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Notes for object MESSIER 077

61 note(s) found in NED.


1. 2009A&A...502..457G
Re:NGC 1068
A.2.1 NGC 1068 is one of the best-studied of obscured AGN; hence our decision to
include it on our correlation. In X-rays, it is known to be substantially
Compton-thick and reflection-dominated, with log N_H_ > 25 (Matt et al. 2000;
Koyama et al. 1989; Iwasawa et al. 1997). By correcting from the observed flux
of X-rays scattered from above the obscuring medium into the line-of-sight or
from the flux of the forbidden [O III] [IMAGE] 5007 A emission line, intrinsic
[IMAGE]log L_2-10_ estimates of ~42.8-44 are derived (Iwasawa et al. 2003;
Panessa et al. 2006; Levenson et al. 2006).
In the mid-IR, several high-resolution studies have been carried out from the
ground revealing bright, extended structures on sub-arcsec scales and beyond
(Bock et al. 2000; Alloin et al. 2000; Galliano et al. 2005b). At the highest
spatial sampling, continuum core fluxes of 9-10 Jy have been reported around
12-microns (Tomono et al. 2001; Mason et al. 2006), and they correspond to
log {lambda}L_{lambda} ~ 43.8.

2. 2008MNRAS.386.2242H
Re:NGC 1068
NGC 1068. It has nuclear spirals, it is identified as pseudo-bulges using
Hubble Space Telescope (HST) optical images by Drory & Fisher (2007).

3. 2008MNRAS.386.2242H
Re:NGC 1068
NGC 1068 - A prominent bar is present in the 2MASS infrared image
(Menendez-Delmestre et al. 2007), while the NED (RC3) type is Sb. The
stellar velocity dispersion is taken from Nelson & Whittle (1995)
measured with an aperture of 1.5 x 2.3 arcsec2 .

4. 2008MNRAS.386.2242H
Re:NGC 1068
NGC 1068. It has nuclear spirals, it is identified as pseudo-bulges using Hubble
Space Telescope (HST) optical images by Drory & Fisher (2007).

5. 2008MNRAS.386.2242H
Re:NGC 1068
NGC 1068 - A prominent bar is present in the 2MASS infrared image
(Menendez-Delmestre et al. 2007), while the NED (RC3) type is Sb. The stellar
velocity dispersion is taken from Nelson & Whittle (1995) measured with an
aperture of 1.5*2.3 arcsec^2^.

6. 2008ApJS..177..148F
Re:3C 071
4.2.1. 3C 71 (NGC 1068, M77); z = 0.003793; A well-known spiral galaxy, and the
archetypal Seyfert 2, NGC 1068 is not truly "radio-loud" in terms of its radio
luminosity. It has an obscured Sy 1 spectrum (Antonucci & Miller 1985) and a
compact (few arcsec) radio jet aligned north-northeast-south-southwest. The
NICMOS data were obtained as part of the NICMOS GTO time by Thompson & Corbin
(1999). The galaxy dwarfs the small NIC2 chip and even the WFPC2 mosaic
(PROPOSIDs 5479, 5754). We were unable to produce an accurate photometric fit to
this object, since we could not estimate the background flux. The spiral
structure and active nucleus are readily apparent on the NICMOS image, as are
numerous globular clusters. There is a vast literature on this source.

7. 2007MNRAS.379.1249D
Re:NGC 1068
NGC 1068 is one of the nearest Seyfert 2 galaxies (D = 14.4 Mpc), and it has
been well studied at different wavelengths. Ho et al. (1997) classified this
active galaxy as a Seyfert of type 1.8, but a dusty torus hides a Seyfert 1
nucleus (Antonucci & Miller 1985; Jourdain et al. 1994). The nucleus of NGC 1068
hosts a radio jet and an ionized cone at PA ~10{degrees} (Muxlow et al. 1996).
Schinnerer et al. (2000b) summarized the different observed morphological
structures: the outer disc and the outer oval, the latter being interpreted as a
primary bar, an H I ring at its outer Lindblad resonance (OLR) and the two-arm
inner spiral at its inner Lindblad resonance (ILR). A secondary NIR bar extends
up to about 16 arcsec. The SAURON data we have presented here have already been
published by Emsellem et al. (2006), and we refer the reader to this paper for a
detailed analysis. Here we only provide a brief description of the revealed
structures.
The stellar continuum map (Fig. 4a) shows elliptical isophotes, elongated
along the PA of the NIR bar. The stellar velocity field (Fig. 4a) shows strong
departures from axisymmetry, with an S-shaped zero velocity line, and a slightly
varying orientation of the kinematic major-axis. The velocity dispersion rises
towards the centre, reaching 200 km s^-1^ at R ~ 10 arcsec, and then presents a
drop in the inner 5 arcsec with values down to about 100 km s^-1^. Gerssen et
al. (2006) observed this galaxy with the Gemini Multi-Object Spectrograph (GMOS)
IFU, covering the central 10 * 8 arcsec^2^. Our stellar kinematic properties are
in good agreement with theirs, although they found a kinematic PA offset by
about 13{degree} from ours, their FOV being too small to detect the change of
orientation of the kinematic major-axis.
H{beta} and [O III] distributions are quite different (Fig. 4a). H{beta}
emission is very high in the inner 5 arcsec, and traces the spiral arms outside
this region. As for H{beta}, [O III] emission peaks in the central parts, with
the distribution of [O III] becoming very asymmetric outwards. It is found
predominantly on the north-east side, tracing the northern ionization cone.
Despite the significant differences between the distribution of the H{beta} and
[O III] line emission, their velocity fields and velocity dispersion maps are
very similar (Figs 4a and B1). The velocity fields of H{beta} and [O III] both
display a prominent S-shaped zero velocity curve, evidence for strong deviations
from circular motions. The velocity dispersion maps of H{beta} and [O III] show
a peak in the central 5-arcsec parts and then reach lower values outside. As
expected, [O III]/H{beta} is high in the region of ionization cone (~10), and
lower in the spiral arms ([O III]/H{beta} < 1), the latter being dominated by
star formation regions (Fig. 4a).

8. 2007ApJ...671.1388D
Re:NGC 1068
A2.5. NGC 1068 Evidence for a stellar core in NGC 1068 with an intrinsic size
scale of ~45 pc was first presented by Thatte et al. (1997). Based on kinematics
measured in large (2"-4") apertures, they assumed that the core was virialized
and estimated a mass-to-light ratio based on this assumption leading to an upper
limit on the stellar age of 1600 Myr.
Making a reasonable correction for an assumed old component led to a younger
age of 500 Myr. Stellar kinematics from optical integral field spectra (Emsellem
et al. 2006; Gerssen et al. 2006) shows evidence for a drop in the stellar
velocity dispersion in the central few arcseconds to sigma}_*_ km s^-1^, inside
a region of higher 150-200 km s^-1^ dispersion (presumably the bulge). Our
near-infrared AO data are able to fully resolve the inner region where
{sigma}_*_ drops, as shown in Figure 21. As for NGC 1097, the velocity
distribution of the stars was derived through kinemetry, again making use of the
uniformity of the stellar velocity field to justify the simplifying assumption
that the position angle and inclination do not change significantly in the
central 4". The derived inclination of 40{degree} and position angle of
85{degree} are quantitatively similar to those found by other authors in the
central few to tens of arcseconds (Emsellem et al. 2006; Gerssen et al. 2006;
Garcia-Lorenzo et al. 1999). The uniformity of the stellar kinematics is in
contrast to molecular gas kinematics, as traced vi a the 1-0 S(1) line, which is
strongly perturbed and shows several distinct structures superimposed. These are
too complex to permit a comparably simple analysis and will be discussed,
together with the residuals in the stellar kinematics, in a future work (F.
Mueller Sanchez et al. 2008, in preparation).
The crucial result relevant here is that at our H-band resolution of 0.10" we
find that {sigma}_*_ reduces from 130 km s^-1^ at 1"-2" to only 70 km s^-1^ in
the very center. That there is in the same region an excess in the stellar
continuum is demonstrated in Figure 22. Here we show the radial profile of the
stellar continuum from both SINFONI integral field spectra out to a radius of 2"
and NACO long-slit spectra out to 5" (350 pc). At radii 1"-5", corresponding
roughly to the region of high stellar dispersion measured by Emsellem et al.
(2006), the profile is well matched by an r^1/4^ law, as one might expect for a
bulge. At radii r < 1" , the same radius at which we begin to see a discernible
reduction in the stellar dispersion, the stellar continuum increases by as much
as a factor of 2 above the inward extrapolation of the profile, indicating that
there is extra emission. As for NGC 1097, the combined signature of dynamically
cool kinematics and excess emission is strong evidence for a nuclear disk t hat
has experienced recent star formation.

9. 2007ApJ...671.1388D
Re:NGC 1068
We can make an estimate of the characteristic age of the star formation in
the central arcsecond based on the mass-to-light ratio in a similar way to
Thatte et al. (1997). Because the stars appear to lie in a disk, we estimate the
dynamical mass as described in {section} 3 from the stellar kinematics, using
the rotation velocity and applying a correction for the dispersion. The stellar
rotation curve is essentially flat at 0.1"-0.5", with V_*_ = 45 km s^-1^
(corrected for inclination). We also take {sigma}_*_ = 70 km s^-1^, which is the
central value and hence least biased by the high-dispersion bulge stars. These
lead to a mass of 1.3*10^8^M_sun_ within r = 0.5" (35 pc) and a mean surface
density of 3 * 10^4^ M_sun_ pc^-2^. Correcting for the nonstellar continuum, the
H-band magnitude (which the behavior of {sigma}_*_indicates is dominated by the
disk emission) in the same region is 11.53 mag. For H-K = 0.15 mag (Fig. 4), we
find L_K_ 4.3 * 10^7^L_{sun}_ and hence M/L_K_ = 3 M_sun_L_sun_^-1^. If no star
formation is ongoing, this implies a characteristic age of 200-300 Myr fairly
independent of the timescale (for t_SF_ Myr, see Fig. 4) on which stars were
formed. We note that this is significantly younger than the age estimated by
Thatte et al. (1997) primarily because their mass was derived using a higher
{sigma}_*_ corresponding to the bulge stars. The assumption of no current star
formation is clearly demonstrated by the Br{gamma} map in Figure 23. Away from
the knots of Br{gamma}, which are associated with the coronal lines and the jet
rather than possible star formation, the equivalent width is W_Br{gamma}_ ~ 4 A.
This is significantly less than that for continuous star formation of any age.
Thus, while it seems likely that star formation has occurred in the last few
hundred million years, it also seems an unavoidable conclusion that there is no
current star formation.
To complete our set of diagnostics for NGC 1068, we consider also the radio
continuum. This is clearly dominated by phenomena associated with the AGNs
and jets, and our best estimate of the flux density away from these features
is given by the lowest contour in maps such as Figure 1 of Gallimore et al.
(2004). From this we estimate an upper limit to the 5 GHz continuum associated
with star formation of 128 mJy within r < 0.5". However, converting to a
supernova rate and comparing to the K-band stellar luminosity yields a limit
that is not useful, being an order of magnitude above the largest expected
values.

10. 2005ApJS..157...59L
Re:NGC 1068
NGC 1068 at a distance of 14.4 Mpc is a Sb spiral galaxy with an outer ring. The
luminosities of ULX1 changed from below 1.5 x 10^39^ ergs s^-1^ to ~4 x 10^39^
ergs s^-1^ between four observations over 5 years. ULX2 is positioned on the
outer ring and showed variability during an 18 day observation.

11. 2004MNRAS.350.1087S
Re:NGC 1068
NGC 1068: an abrupt fall in the surface brightness profile (see Paper I)
is observed at r{approx} 2.2 kpc, leading to an 'inner' and an 'outer'
disc. Alternatively, this feature in the surface brightness profile can
be attributed to the existence of a circumnuclear star-forming ring
whose intensity peaks around 1.5 kpc (Diaz et al. 2000). This fact,
along with the poor seeing conditions during the observations (~2.2
arcsec FWHM), prevented us from performing an acceptable parameter
decomposition.

12. 2004MNRAS.350.1049G
Re:NGC 1068
9.6 NGC 1068 The archetype S2 galaxy, NGC 1068 has been discussed in
detail by Glass (1995). The J - H colour of its variable component is
not well-determined, but the H - K and K - L colours are by far the
reddest of the sample.

13. 2004A&A...415..941E
Re:NGC 1068
NGC 1068 (M 77): Schinnerer et al. (2000). Depending on how one counts,
as many as five separate bars have been suggested for this galaxy. The
bar universally agreed upon is that first found in the near-IR by
Scoville et al. (1988), with a ~ 17". Schinnerer et al. (2000)
presented both imaging and kinematic evidence for a much larger, rounder
bar outside; this is the same as the "oval disk" discussed by Kormendy
& Norman (1979). This galaxy is thus similar to NGC 4736 (below): a
fairly strong and large inner bar resides inside a very large, weak
outer bar/oval disk. The measurements presented here are based on the
images and ellipse fits of Alonso-Herrero et al. (1998) for the inner
bar (with L_bar_ based on the size of the nuclear pseudo-ring
surrounding it) and on the 2MASS J-band image for the outer bar.
Distance, inclination, and outer-disk PA are from Schinnerer et al. and
references therein.
Other studies have proposed additional, smaller bars for this galaxy,
but the evidence for these is ambiguous or dubious. Rouan et al. (1998),
using adaptive-optics, near-IR images and archival F547M WFPC2 images,
suggested no fewer than three nested bars, all smaller than the
well-known 17" bar (i.e., the inner bar in this catalog). At least some
of these features are probably due to dust and scattered nuclear
radiation, and possibly the radio jet as well (Weinberger et al. 1999;
Bock et al. 2000). Finally, Laine et al. (2002) reported two bars: the
well-known IR bar, and a smaller bar with deprojected a = 1.7",,
possibly matching the middle of Rouan et al.'s three bars. But
Schinnerer et al. found no evidence for a nuclear bar on those size
scales, and argued instead for a warped molecular disk, which might
explain some of the features seen by Rouan et al. and Laine et al.

14. 2003MNRAS.343..192R
Re:NGC 1068
3.1 NGC 1068 NGC 1068 is a nearby (z = 0.00379; distance = 15.1 Mpc)
(R)SA(rs)b galaxy. It has an extensively studied Sy2 nucleus with high
extinction derived towards the BLR A_v_ > 50 mag), as evidenced by the
non-detection of broad Br{alpha} 4.05 micron (Lutz et al. 2000).
NGC 1068 also harbours a star-forming ring with diameter ~15 arcsec
(~1.1 kpc; e.g. Davies, Sugai & Ward 1998). Rouan et al. (1998) found
K-band extended emission along PA = 102deg, up to 15 pc in radius,
interpreted as the equatorial plane of an inclined torus. This extension
can also be seen in the LM-bands (Marco & Alloin 2000). NGC 1068 has an
[O III] cone, which extends to ~7.5 arcsec at PA = 35deg (Evans et al.
1991).
The H- and K-band nuclear spectrum of NGC 1068 (Fig. 2)
resembles that of NGC 5128 (Paper 1), having an almost power-law like
continuum shape. The most prominent features in the nuclear spectra are
the coronal lines [SiVI] 1.964 {microns}, [Ca VIII] 2.321 {microns} and
[Si VII] 2.483 {microns}. The other emission lines detected in the nucleus
are [Fe II] 1.644 {microns}, H_2_ 1-0 S(1) 2.122 {microns} and Br{gamma}
2.166 {microns}. Pa{alpha} 1.876 {microns} is also prominent, but its
usefulness is limited by telluric residuals. Nuclear H2 emission is faint.
1-0 S(1) is the most extended line and is detected up to 5-7 arcsec
(300 pc) from the nucleus parallel to the cone and up to ~4 arcsec
perpendicular to it. [Fe II] and Br{gamma} are extended ~4 arcsec from the
nucleus. Br{gamma}, [Fe II], H2 and He I 2.058 {microns} are furthermore
detected in the star-forming ring ~15 arcsec (~1.1 kpc) from the
nucleus. [SiVI] 1.964 {microns} is the strongest emission line in the
nucleus, [Fe H] is the strongest emission line in between the nucleus
and the ring, and Br{gamma} is the strongest emission line in the ring.
However, generally the equivalent widths of the emission lines in the
ring are smaller than e.g. in the rings of NGC 1097 (Paper I; Kotilainen
et al. 2000) or NGC 1365 (see below).
The kinematics of NGC 1068 has been discussed in detail by Schinnerer
et al. (2001) based on CO millimetre lines and by Alloin et al. (2001),
based on H_2_ emission. The velocity curve of [Fe II] parallel to the
cone is much steeper within the inner 3 arcsec (230 pc) than that of
H_2_. At larger radii, [Fe II] seems to follow H_2_ more
closely. Furthermore, within the steep part of the velocity curve, the
kinematics of the [Fe II] depends only on the position along the slit.
Thus it seems very likely that [Fe II] is excited by the outflowing
material in the jet. In addition, parallel to the cone [Fe II] has two
velocity components and thus the line profile changes within the inner
few arcsec (Fig. 9). Similar structure is also visible in the Br{gamma}
and coronal lines.

15. 2003MNRAS.343..192R
Re:NGC 1068
The nuclear [Fe II]/Br{gamma} ratio = 4 (Table 3) is higher than star
formation models predict (e.g. Colina 1993). The 1-0 S S(1)/Br{gamma}
ratio = 0.4 is in agreement with the star formation origin for H_2_ as
a result of UV heating from OB stars (Puxley, Hawarden & Mountain
1990). Whether the heating mechanism is thermal or fluorescence is not
clear, because no 2-1 S(I) or 1-0 S(0) emission was detected in the
nucleus.
The derived parameters, including the density and mass of the molecular
hydrogen both in the nuclear 1.4-arcsec aperture and integrated within
the star-forming ring as traced by Br{gamma}, and the spatial extent of
different lines, are given in Table 3. In the nuclear 1.4-arcsec
aperture, the column density of the excited molecular hydrogen is 1.3 x
10^19^ cm^-2^ (corresponding to M_H_2_,_ = 1800 M_{sun}_), assuming T =
2000K. The FWHM size of the nuclear H_2_emission cannot be measured
reliably as the emission is weak with respect to the continuum.
Several IR coronal lines have previously been detected in NGC 1068
(e.g. Oliva & Moorwood 1990). All the detected coronal lines ([Si VI]
1.964 {microns}, [Ca VIII] 2.321 {microns} and [Si VII] 2.483 {microns})
are resolved parallel to the cone (Fig. 9), and are more extended
towards north (~2 arcsec) than south, in agreement with the NICMOS image
of [SiV I] emission by Thompson et al. (2001). The velocity curves of
the coronal lines resemble the weaker of the two [Fe II] velocity
components. Extended coronal line emission can in principle only be
excited by shocks in the interstellar medium that are produced either by
a jet or AGN-generated winds.

16. 2003ApJS..148..327S
Re:NGC 1068
5.8. NGC 1068
The [O III] image of this Seyfert 2 galaxy is shown in the top right
panel of Figure 6. This image shows that most of the [O III] emission
originates in a V-shaped region with opening angle of 50^deg^,
extending for approximately 10" (750 pc) along P.A. = 35^deg^, and
5.8" (430 pc) in the direction perpendicular to the cone. The
direction of this emission is coincident with the radio jet observed
by Wilson & Ulvestad (1982b). Emission extending to regions farther
away from the nucleus can be seen toward the NE and SE. NGC 1068 is
the most extensively studied Seyfert 2 galaxy in the literature. It
was the first one where polarized broad emission lines were detected
(Antonucci & Miller 1985), as well as the first one to be shown to
have a conically shaped NLR (Pogge 1988a). The HST images of this
galaxy were discussed in detail by Evans et al. (1991), Macchetto et
al. (1994), Capetti, Axon, & Macchetto (1997), Bruhweiler et al.
(2001). Studies of the kinematics of the NLR gas show outflows and a
strong interaction between the gas and the radio source (Axon et al.
1998; Cecil et al. 2002). The radio emission is extended along P.A. =
33^deg^ on the larger scales (Wilson & Ulvestad 1982b) but is aligned
along the N-S direction in the nuclear region (Muxlow et al. 1996;
Gallimore et al. 1996). The high-resolution X-ray images obtained
with Chandra (Young, Wilson, & Shopbell 2001) also show extended
emission aligned with the radio and [O III].

17. 2003ApJS..146..353M
Re:NGC 1068
NGC 1068 (CS)
This extremely well studied galaxy has numerous short dust lanes in a
spiral pattern, but these arms do not have the coherence of the
loosely wound nuclear spirals. We therefore classify this as a chaotic
spiral.

18. 2003ApJS..146..249B
Re:NGC 1068
5.3. NGC 1068
The maser source in NGC 1068 has been studied extensively by Baan &
Haschick (1996) and Gallimore et al. (2001) and has not been part of
our long-term monitoring program. We do present a GBT spectrum in
Figure 2.

19. 2003ApJS..146....1W
Re:NGC 1068
NGC 1068.-This object is bright, and in the O VI {lambda}1031.926 region
the flux is even higher because of the wing of strong O VI emission
(peak flux 8.5 x 10^-13^ erg cm^-2^ s^-1^ {angstrom}^-1^) intrinsic to
NGC 1068. The continuum still seems fairly easy to determine in the
region near 1032 {angstrom}.
There is a feature centered at 1033.463 {angstrom} (445 km s^-1^ on the
O VI velocity scale). This is probably O VI associated with NGC 1068,
although its counterpart is confused with the low-velocity Galactic O I
{lambda}1039.230 absorption. NGC 1068 is part of the Cetus-Aries Galaxy
Grouping (v = 1810 +- 510 km s^-1^), but none of the galaxies near
NGC 1068 that are part of this group has a velocity as low as
500 km s^-1^, so no intergalactic Ly{beta} is expected.

20. 2003ApJ...598..827P
Re:NGC 1068
NGC 1068 (M77).-NGC 1068 is the nearest example of a type 2 Seyfert
galaxy. Differences in the UV optical colors of the active nucleus,
bright star-forming knots, and diffuse, extended disk dominate the
internal color dispersion (as shown in the residual color image in
Fig. 2). To ascertain the contribution of the active galactic nucleus
(AGN) to the total internal color dispersion, we recomputed after
masking out the galaxy center and observed little change in the
resulting internal color dispersion. Therefore, the high internal color
dispersion value is probably a result of patchy dust opacity within the
nuclear starburst (see also Neff et al. 1994).

21. 2002ApJ...574..740T
Re:NGC 1068
NGC 1068.
The black hole mass is taken from Greenhill & Gwinn (1997); the
error estimates are our own and are very approximate. The
dispersion (Kobulnicky & Gebhardt 2000) is somewhat uncertain
because of contamination from the bright nucleus.

22. 2002AJ....124..675C
Re:UGC 02188
Unusually warm FIR source: alpha(25,60) = 0.83. CfA Seyfert 2 (Huchra
& Burg 1992).

23. 2002A&A...389...68G
Re:NGC 1068
NGC 1068: the HII regions are placed only in the inner bright
oval, and the values obtained using both methods, while in
agreement, are inadequate. The values given by
Sanchez-Portal et al. (2000) also pertain to the inner bright
oval. Thus, we take the mean of the values from the velocity
fields.

24. 2001MNRAS.327..459L
Re:NGC 1068
NGC 1068: This is the best studied of all the HBLRs currently known. We
now know that the likely orientation of the parsec-scale torus in this
galaxy is nearly edge-on from direct radio imaging (Gallimore, Baum & O'Dea
1997). Unfortunately, the structure of the inner regions of NGC 1068 is
actually rather complex, since there is a small parsec-scale radio
structure aligned with the axis of this torus that is also visible in
[O III] images and imaging polarimetry from HST (Capetti et al. 1995;
Muxlow et al. 1996; Capetti, Axon & Macchetto 1997), but the larger scale
radio structure and visible ionization cones are rotated through ~30^deg^
relative to these (Capetti et al. 1997).
This complexity may, however, help to explain the variant requirements
of the X-ray and the optical/infrared data. The BeppoSAX data reported by
Guainazzi et al. (2000) show evidence for considerable variability in the
hard X-ray emission from NGC 1068. They use this to constrain the location
of the scattering medium at ~1 pc from the nucleus. Since the Fe K{alpha}
line is fed by resonance scattering from a largely neutral medium, it
further implies the obscuring torus is also ~1 pc from the nucleus. Indeed,
as has previously been noted (Risaliti et al. 1999), unless the bulk of the
obscuration lies at small radii, the implied mass of molecular gas would
exceed the observed virial mass in NGC 1068 and other nearby AGN. However,
there is also clearly scattering on larger scales as detected both in the
near-infrared by Packham et al. (1997) and Lumsden et al. (1999), and in
the ultraviolet by Capetti et al. (1995). Young et al. (1996b) found that
a large-scale torus (~200 pc) is required to explain the infrared data,
whilst still requiring the inner scattering radius to be ~1 pc to explain
the optical spectropolarimetry (Young et al. 1995). The solution to this
apparent dichotomy lies in the fact that there are clearly two levels of
obscuring source in NGC 1068. The mid-infrared polarimetry of
Lumsden et al. (1999) requires a compact, optically thick (A_V_ ~ 100)
region around the BLR, with a more diffuse, larger scale molecular cloud
with A_V_ = 30 hiding that region and the inner scattering cones. This
latter region is also revealed in maps of the molecular gas near the
nucleus (Schinnerer, Eckart & Tacconi 1999). Clearly, this also implies,
however, that the reflected X-ray component should itself be partially
absorbed. In the case of NGC 1068, if our estimate of the visual extinction
is correct, and the conversion to a column density is ~1/10 that of the
Galactic ISM (which is typical of AGN), then the implied
N_H_ ~ 5 x 10^21^ cm^-2^. This is sufficiently small to remain unnoticed
in the existing data. NGC 1068 should be taken as a cautionary example
that local conditions can play a large role in the final global spectral
properties of a galaxy.
Finally, we note that the circumnuclear starburst that lies at a radius
of ~1 kpc from the nucleus may actually dominate the far-infrared flux from
NGC 1068 (Telesco et al. 1984). This suggests that the warmth of the
infrared colours is in fact due to the dominance of the AGN component at
shorter wavelengths.

25. 2001ApJS..136...61S
Re:NGC 1068
5.5. NGC 1068
NGC 1068 is the nearest Seyfert 2 galaxy and has been very extensively
studied. NGC 1068 has a polarized optical spectrum similar to that directly
observed in Seyfert 1 nuclei, with FWZI ~ 7500 km s^-1^ for the Balmer
lines (Antonucci & Miller 1985). A compact stellar cluster has been found
by Thatte et al. (1997), and they show that its contribution to the total
bolometric nuclear (within a radius 2.5") luminosity is at least 7%. They
also observe that 94% of the light in the K band in the central 1"
originates from a compact source which they interpreted as hot dust
emission. The [O III] line emission morphology has a conical shape which
extends 7.5" at P.A. 35^deg^ with opening angle 45^deg^ (Evans et al.
1991). A ring of star formation (of outer diameter 36") apparently powers
half of the mid-/far-IR luminosity, while the other half comes from the
Seyfert nucleus (Pogge & de Robertis 1993). Significant amounts of hot
dense molecular gas is shown by the H_2_ 1-0 S(1) line emission extending
over a region of 350 pc around the nucleus (Rotaciuc et al. 1991;
Blietz et al. 1994) and thought to be excited in the gas heated by UV
radiation or by X-ray photons from a central source (Rotaciuc et al. 1991).
Weak H_2_ 1-0 S(1) line emission, possibly due to shock excitation, also
extends for 10" along the stellar bar (Davies, Sugai, & Ward 1998;
Scoville et al. 1988). Our H_2_ 1-0 S(1) line map agrees very well with
the bright inner regions of the map from Davies et al. (1998) (see their
Fig. 4). The [Fe II] {lambda}1.644 micron forbidden line has been mapped
(Blietz et al. 1994) and compared to the structure of the radio elongated
emission (Wilson & Ulvestad 1983). The [Fe II] {lambda}1.644 micron and
radio emission line are colinear, with the lobes of the radio emission
"flaring out" at the end of the significant [Fe II] {lambda}1.644 micron
emission. A forbidden [Si VI] {lambda}1.962 micron line has been detected
(Oliva & Moorwood 1990) in this object, however, in our spectrum this
spectral region is not covered. Elvis & Lawrence (1988) present EXOSAT
observations in the 2-10 keV range. They detect a source with a flat
power-law spectrum which resembles that of typical Seyfert 1 galaxies.
Within their observations they do not find evidence of variations on
timescales of 30 minutes to 4 years. They use this as evidence that the
direct view of the nucleus is totally obscured and the X-ray flux observed
is seen only in scattered light.

26. 2001ApJS..133..269L
Re:NGC 1068
5.1. NGC 1068
NGC 1068 is a member of a group (Garcia 1993) and contains a stellar bar
(Thronson et al. 1989). Broad optical emission lines are observed in
polarized light (Antonucci & Miller 1985). The X-ray emission from NGC 1068
has been studied in detail (Wilson et al. 1992; Ueno et al. 1994;
Iwasawa et al. 1997; Netzer & Turner 1997), and its spectrum is extremely
complex.
For consistency, we present the simple model fits to the spectrum,
although none of these are satisfactory. The best-fit model includes a
power law, two thermal components, and three Gaussian components. The
intrinsic power law of the AGN is completely absorbed. In these joint fits
of ASCA and PSPC data, we have rejected SIS data at energies E < 0.8 keV,
because the SIS calibration of such bright, soft sources at low energies
is highly uncertain (Weaver, Gelbord, & Yaqoob 2001). We find that 80% of
the soft X-ray emission is thermal.
NGC 1068 is clearly extended in X-ray emission, and the soft and hard
PSPC bands are distinct. Although a radio jet has been observed
(Wilson & Ulvestad 1982), the extended X-ray emission is associated with
the starburst, not the jet (Wilson et al. 1992). Measured with both the
HRI and the PSPC, the soft X-ray emission extends on scales greater than
7.4 kpc.

27. 2001ApJS..133...77H
Re:NGC 1068
NGC 1068, M77 (S1.9). - This well known source has been extensively
studied by many authors (e.g., Wilson & Ulvestad 1982b, 1983; Ulvestad,
Neff, & Wilson 1987; Kukula et al. 1995; Gallimore, Baum, & O'Dea 1996).
In addition to the prominent lobes associated with the AGN, our maps show
traces of the 30" diameter (~2 kpc) circumnuclear ring. Our measurement
of the 6 cm core is in good agreement with the results of van der Hulst
et al. (1981), whose data had a similar resolution as ours. Wilson &
Ulvestad (1983) reported linearly polarized 6 cm emission associated with
the core and the northern lobe of NGC 1068. We detected these components
(S_pol,6_^I^ = 0.91 mJy and 5.1 mJy, respectively), and, in addition, we
find significant polarization (S_pol,6_^I^ = 5.3 mJy) associated with the
low-surface brightness feature to the northeast of the core (Fig. 16a).
At 20 cm, the polarized signal near the core and in northern lobe can
still be seen (S_pol,20_^I^ = 1.2 mJy and 1.1 mJy, respectively), although
the northeastern feature appears much weaker.

28. 2001ApJS..132..129M
Re:NGC 1068
NGC 1068 (M77). - An SA(r)b disk system, NGC 1068 is the prototype
Type 2 Seyfert galaxy and one of the nearest galaxies harboring an
AGN (D ~ 15.1 Mpc). In addition to the active nucleus, the optical disk
exhibits a number of unusual features, most prominently a high surface
brightness inner disk and a population of luminous knots.
Neff et al. (1994) provide a detailed description of the UV morphology
of NGC 1068; the UV photometry is discussed by Fanelli et al. (1997a). The
UV images, presented in Figure 8a, show the bright AGN, a population of
very luminous starburst knots, a bright oval inner disk, and a fainter,
more circular halo. The UV knots were first studied with IUE spectra and
were found to be sites of intense recent massive star formation (Snijders,
Briggs, & Boksenberg 1982; Weedman & Huenemoerder 1985; Bruhweiler, Truong,
& Altner 1991; Hutchings et al. 1991). The brightest knot complex, located
~750 pc from the nucleus in PA ~ 315^deg^, has ~80 times the luminosity of
30 Dor and gives NGC 1068 a "double nucleus" appearance at UV wavelengths,
in marked contrast to its optical morphology. The radial decline of the
azimuthally averaged UV surface brightness (Fig. 8b) can be followed for
over 8 mag. The plateau in the light profiles associated with the inner
disk (r <~ 60") is more pronounced in the UV than the R band. Both the MUV
and R profiles flatten at r ~ 100". Neff et al. (1994) suggest that the
UV halo is either indirect light from the UV-bright inner disk that is
scattered by dust grains, or direct UV radiation from the stellar
population in the outer disk. The absence of a significant change in the
MUV-R color suggests the latter model, since one expects the dust to
preferentially scatter the UV light. Despite the bright AGN, the stellar
disk produces 81% of the integrated FUV and 83% of the MUV flux. The bright
disk emission in NGC 1068 implies that even at UV wavelengths, the
contribution of an active nucleus to the total light can be small and that
composite AGN + starburst objects will be difficult to interpret at large
redshift.

29. 2001ApJ...562..139M
Re:NGC 1068
NGC 1068. - The elliptical isophote fits to this galaxy were compromised
by significant circumnuclear dust and the bright nuclear point source. The
nuclear point source is particularly prominent at H, which supports the
interpretation that this galaxy harbors a dust-obscured broad-line region,
first suggested by the polarization study by Miller & Antonucci (1983).
While this nearly face-on galaxy shows significant radial ellipticity
variations in J and H, these variations are clearly uncorrelated as they
reach a peak at ~1.5" in J but ~0.7" in H. The much larger variation in J
is likely due to dust. The ellipticity variation at 0.7" in H is coincident
with a variation in the surface brightness profile and is due to the PSF
diffraction pattern.

30. 2000MNRAS.318..173M
Re:NGC 1068
2.1 NGC 1068
The archetypal Seyfert 2 and Compton-thick source NGC 1068 has been
observed by BeppoSAX twice, one year apart. The nucleus is completely
obscured at all energies (Matt et al. 1997), and therefore the column
density of the absorbing matter should exceed ~10^25^ cm^-2^. The soft
X-ray band is dominated by thermal-like emission, probably related to the
starburst region. In the 2-10 keV band, the emission is a mixture of cold
and ionized reflection (see also Iwasawa, Fabian & Matt 1997), the latter
being complex as implied by the line spectrum (Netzer & Turner 1997;
Guainazzi et al. 1999). At higher energies, it is the cold-reflection
component which dominates.
There is also evidence for energy-dependent flux variability
(Guainazzi et al. 2000b), best explained by a variation of the spectral
shape of the ionized reflector component, obviously echoing a variation in
the primary, nuclear continuum. This would limit the dimension of the
reflecting region to less than 1 pc.

31. 2000ApJ...534..670T
Re:NGC 1068
NGC 1068.-The M/L in the disk region increases slowly by 4.6 times from
r = 2 to 6 kpc. In the bulge region it decreases more rapidly (0.28
times from r = 2 kpc to 800 pc) than in the disk but within r = 800 pc
turns to be nearly flat or somewhat increasing. This is a type 2 Seyfert
galaxy, so the luminosity profile in the V band may be not exact in the
central region.

32. 1999ApJ...524..684G
Re:NGC 1068
NGC 1068 is the prototype of Seyfert 2 nuclei but is also the first
Seyfert found to have a Seyfert 1 spectrum in polarized light (Antonucci
& Miller 1985). Baan & Haschick (1983) originally reported H I
absorption seen as a sharply defined trough in the H I emission profile.
Our observations resolve out H I emission, and the H I absorption is
spatially resolved. The main results were originally presented in
Gallimore et al. (1994). The bulk of the absorption traces the inner
disk of the host galaxy, seen against the southwestern radio structure.
There is kinematic evidence that the gas is responding to the kiloparsec
scale stellar bar. Closer to the nucleus the absorption lines broaden,
and there appear multiple velocity components. The opacity of the
absorption-line gas also appears to increase, but toward the nucleus the
opacity seems to drop sharply. VLBI studies have failed to detect the
nucleus (radio component S1) in 21 cm radio continuum (Roy et al. 1998).
The apparent drop in opacity is probably a resolution effect owing to
the lack of a background radio source. There may be a broad absorption
profile very near the nucleus, whose kinematics are consistent with the
rotating H_2_O maser disk (Gallimore et al. 1996a), but bandpass
calibration uncertainties preclude a confident detection in the present
observations.

33. 1999ApJ...516...97N
Re:NGC 1068
NGC 1068: Radio source S1 is generally believed to represent the
location of the active nucleus, based on its spectrum (Gallimore, Baum,
& O'Dea 1996), morphology (Gallimore, Baum, & O'Dea 1997), and the
presence of water vapor masers (Greenhill et al. 1996). The P.A. between
sources S1 and S2 (Gallimore et al. 1996; their Figure 1) is -6^deg^,
while the P.A. between sources S1 and C is 13^deg^. We adopt a radio
P.A. of 0^deg^. RC3 lists a photometric major axis P.A._RC3_ = 70^deg^
and log R_25_ = 0.07. H I kinematic data (Brinks & Mundell 1996) show
that the galaxy disk is warped, with a major axis P.A. (P.A._H I_) that
increases from 95^deg^ in the high surface brightness inner ring to
115^deg^ in the faint outer extensions at radius ~200". Thus,
P.A._RC3_ -P.A._H I_ = 45^deg^.

34. 1998ApJ...495..196A
Re:NGC 1068
3.5.3. NGC 1068
In Figure 5 (Plate 3) we present the J-band image divided by the model of
NGC 1068 superimposed on the J-band continuum image (note that due to the
brightness of this galaxy, the K-band image shows a ghost image of the nucleus,
and therefore the fitting is not reliable at that position). The solid contours
(emission in excess over the galaxy model) clearly show an impressive stellar
bar and the inner spiral arms. The bar runs from northeast to southwest at
position angle P.A.=45^deg^-50^deg^, approximately 36" (4 kpc) in extent, and
between 3" and 6" (300-600 pc) in width, in good agreement with the results
found by Thronson et al. (1989) at 1.6 and 2.2 microns. Furthermore, the
resemblance of the deviations from the symmetric model to the "lumpy"
morphology seen in the CO map presented by Helfer & Blitz (1995) is remarkable,
although the P.A. of the molecular bar is slightly different (63^deg^). The
orientation of the bar differs from the kinematic and photometric major axis of
the galaxy disk (P.A.=80^deg^+/-9^deg^; Baldwin, Wilson, & Whittle 1987). The
[O III] {lambda}5007 emission-line region of this galaxy has a conical shape
extended by 7.5" at P.A.=35^deg^, with opening angle 45^deg^ (Evans et al.
1991). The L'-band image shows emission within 5" of the nucleus, with 85% of
the total emission unresolved and associated with the nucleus, whereas the
extended emission at this wavelength follows the orientation of the J, H, and K
inner isophotes (Fig. 1c).
In addition to the bar, there is a ringlike structure or perhaps inner spiral
arms in the J-band image, with outer diameter ~36", similar to the 10 microns
structure found by Telesco et al. (1984) and the morphology in the UV/red
continuum color map presented in Pogge & DeRobertis (1993). These authors show
that roughly half of the mid-/far-IR emission from NGC 1068 originates from the
Seyfert nucleus and half from the disk surrounding it, with the disk being
powered by star formation. The near-IR colors within an annulus with inner
diameter 30" and outer diameter 36" (i.e., bracketing the ring) are J-H=0.78
and H-K=0.27, consistent with the colors of normal spiral galaxies, whereas the
colors of the nucleus itself (for a 3" diameter aperture) are extremely red:
J-H=1.15, H-K=1.10, and K-L'=3.70, and can best be represented in terms of a
combination of unreddened starlight plus obscured hot dust emission (with a
blackbody temperature T~800 K), as explained above. The ratios of the total
fluxes in the ring to the nuclear emission (defined as the region interior to
the stellar bar, within a 6" diameter aperture) in the observed images are
0.80, 0.65, and 0.37 at J, H, and K band, respectively, which demonstrates the
increasing dominance of the nuclear emission toward longer wavelengths.

35. 1998AJ....116.2682C
Re:IRAS 02401-0013
NGC 1068. Seyfert 2; hidden Seyfert 1.

36. 1997ApJS..113...23T
Re:NGC 1068
A3. NGC 1068
NGC 1068 is one of the nearest and brightest Seyfert 2 galaxies; consequently,
it has been studied in great detail at all wavelengths. NGC 1068 was the first
Seyfert 2 galaxy for which broad optical emission lines were discovered in the
polarized component of the optical spectrum (Antonucci & Miller 1985), a
discovery which led to the unified model picture of Seyfert 2 galaxies as
hidden Seyfert 1 nuclei. Comparing the width of the polarized H{beta} line on-
and off-nucleus, Miller, Goodrich, & Mathews (1991) derived an average
temperature of ~2x10^5^ K. Imaging spectroscopy of the 2 microns H_2_ 1-0 S(1)
line has shown significant amounts of hot, dense, molecular gas extend over a
350 pc region surrounding the nucleus (Rotaciuc et al. 1991; Blietz et al.
1994). An EXOSAT observation of NGC 1068 found an unabsorbed spectrum. Lawrence
& Elvis (1982) suggested this indicated that the observed 2-10 keV spectrum of
NGC 1068 was a scattered component, and a large column must exist, completely
hiding the central engine and undetectable below 10 keV. A BBXRT observation of
NGC 1068 also found the X-ray continuum to be well described by a double power
law with no evidence for absorption (Marshall et al. 1993). Those authors also
resolved three components to the iron K-shell line emission, totaling an
equivalent width of 2700 eV, as well as unresolved soft X-ray lines, which were
attributed to emission from the iron L-shell. The line energies observe
indicated a broad range of ionization states exist within the gas. The ROSAT
HRI data show that half the soft X-ray emission comes from an unresolved
pointlike source and half from an extended region (Wilson et al. 1992). The
flux of the extended emission region is consistent with its origin from the
starburst activity in the host galaxy. Hubble Space Telescope (HST)
observations have resolved a 1"-2" region in which the UV scattering occurs in
NGC 1068 (at the distance of NGC 1068, 1" is ~70 pc assuming H_0_=75 km s^-1^
Mpc-1 and q_0_=0.5).
The presence of a multitude of soft X-ray emission lines was confirmed in the
ASCA PV observation of this source (Ueno et al. 1994), and we present our
analysis of those data here.

37. 1997ApJS..112..391H
Re:NGC 1068
NGC 1068.--Malkan & Filippenko (1983) first remarked that the Seyfert nucleus
of NGC 1068 may have weak broad H{beta} emission, although they did not
explicitly model the line profile to measure the broad line. The existence of a
broad-line region (BLR) in this object was subsequently demonstrated
conclusively by Antonucci & Miller (1985), whose spectropolarimetric
observations showed that the polarized spectrum closely resembled that of a
typical Seyfert 1 nucleus. Here we wish to reexamine whether the broad
component of H{beta} and H{alpha} can be detected in the total-light spectrum.
The kinematics and spatial distribution of the narrow-line region in NGC 1068
are notoriously complicated. It has long been known that the line-emitting
material within the central several hundred parsecs consists of a number of
distinct, high-velocity clumps (Walker 1968) that combine to produce very
complex, exceptionally broad line profiles (see, e.g., Pelat & Alloin 1980),
that the integrated line profile changes dramatically over small angular scales
(see, e.g., Alloin et al. 1983; Baldwin, Wilson, & Whittle 1987), and that the
line-intensity ratios of the different velocity components do not remain
constant throughout the nuclear region (Baldwin et al. 1987; Cecil, Bland, &
Tully 1990). Thus, we anticipate at the outset that many of the assumptions
employed thus far in this study are unlikely to be applicable in NGC 1068.

38. 1997ApJS..112..391H
Re:NGC 1068
We begin with the H{beta} line, since it is much less blended with surrounding
lines than H{alpha} is. Although the profiles of H{beta} and [O III] differ in
detail, previous studies indicate that these two lines roughly trace each other
in overall shape (see, e.g., Cecil et al. 1990; Veilleux 1991), especially as
seen in data with moderate spectral resolution. We therefore constrain the
narrow component of H{beta} to have the same profile as that of [O III]. An
additional Gaussian was then introduced to test for the presence of possible
broad H{beta} emission. We leave the height of the Gaussian unconstrained but
fix the FWHM to be 3210 km s^-1^ and the line center redshifted by 600 km s^-1^
with respect to the narrow component; these parameters, taken from the
spectropolarimetric study of Miller, Goodrich, & Mathews (1991), pertain to the
polarized broad H{beta} profile from nucleus and should be identical to that of
the hypothetical component viewed in total light. We cannot allow too much
freedom in the fit for the broad component because the extended bases of the
narrow lines, especially the blue wing anticipated from [O III] {lambda}4959,
can easily lead to an erroneous, even if formally acceptable, solution. Our
best-fit model for each of the [O III] lines (Fig. 5a) consists of a sum of
five Gaussians: four have FWHM~400-600 km s^-1^ and contain about half of the
flux and another is considerably broader (FWHM~1900 km s^-1^) and slightly
blueshifted (~190 km s^-1^) relative to the main narrow component. The broad,
blueshifted feature identified here most likely corresponds to a similar
component seen in many previous studies (see, e.g., Pelat & Alloin 1980; Alloin
et al. 1983; Caganoff et al. 1991) and lends confidence that our model for the
narrow lines is qualitatively correct. Under this assumption, the fit for the
H{beta} line does require a BLR component (bottom, Fig. 5a). Interestingly, the
broad H{beta} line has roughly the strength expected from the detailed model by
Miller et al. for the scattered line flux of the nucleus. The broad line we
detect constitutes ~19% of the integrated flux of H{beta}, and it has 1.8% of
the total intensity of [O III] {lambda}5007. Although our observations of this
source were not taken under photometric conditions, we can estimate the flux of
the broad H{beta} line as follows. Assuming, as did Miller et al., that the
flux of [O III] {lambda}5007 is 1.7x10^-11^ ergs s^-1^ cm^-2^ (Shields & Oke
1975), the flux of broad H{beta} should be 3.1x10^-13^ ergs s^-1^ cm^-2^, in
very close agreement with the value of 3.7x10^-13^ ergs s^-1^ cm^-2^ estimated
by Miller et al.

39. 1997ApJS..112..391H
Re:NGC 1068
The H{alpha}+[N II] region is considerably more complicated. In addition to the
severe blending of the broad, complex lines, it appears that the intrinsic
narrow-line profile of H{alpha} does not match that of [N II]. If we construct
an analytic model from [S II] as usual (Fig. 5b), it is evident that the [S II]
lines have a much more extended blue tail than [O III]; a broad component is
again evident (FWHM~2050 km s^-1^), but it is significantly more blueshifted
(~1000 km s^-1^). Thus, a priori, we expect that making the assumption that the
profiles of [S II], [N II], and H{alpha} are equal is invalid, since H{beta},
which presumably should be nearly identical to H{alpha}, is well fitted by
[O III]. On the other hand, we find that [O III] clearly does not match [N II],
whereas [S II] approximately does. Accordingly, we constructed a model such
that H{alpha} and [O III] had identical profiles and [N II] and [S II] had
identical profiles, and we once again added an extra Gaussian to test for the
presence of broad H{alpha} emission. As in the case of H{beta}, we fixed the
position and the width of the Gaussian. Under these assumptions, we also find
evidence for a BLR component of H{alpha} (Fig. 4f). Although the fairly large
residuals indicate that our fit is far from perfect, omitting the BLR component
results in much larger residuals. As with the BLR component of H{beta}, the
broad H{alpha} line contains ~20% of the total flux of H{alpha}, and it has a
sensible strength--the ratio of broad H{alpha} to broad H{beta} is 7, close to
values typically seen in Seyfert 1 nuclei (see, e.g., Netzer 1990).
To summarize, our profile analysis suggests that both the H{alpha} and the
H{beta} emission lines display a broad component in the total-light spectrum.
We believe that this broad component arises from the BLR and is distinct from
the high-velocity emission associated with the narrow-line region. Our
measurement of this component, however, is by no means straightforward, and
because of the simplifying assumptions that had to be adopted, we cannot be
sure that our profile fits are unique. Nevertheless, it is encouraging that the
derived strength of the broad H{beta} line agrees so well with the predictions
of the Miller et al. (1991) model and that the results of the H{alpha} fit are
consistent with those of the H{beta} fit. It is of historical interest to note
that, based on these results, NGC 1068 technically should not be classified as
a Seyfert galaxy of type 2 but, rather, as one of type 1.8 (weak broad H{alpha}
and H{beta}: Osterbrock 1981).

40. 1997ApJS..108..155G
Re:NGC 1068
This is the most famous S2 galaxy. In the disk we detect 109 H II regions
tracing the two spiral arms. Closer to the center, the appearance of the
H{alpha} emission is that of an elliptical ring of radii 14" J 12" (~1
kpc); see expanded plot in Fig. 11a. The isophotes are oriented at P.A. =
50^deg^, and a tongue (as denoted by Balick & Heckman 1985) emerges at
P.A. = 140^deg^ and falls toward the north. This object is one of the
best examples in which a circumnuclear starburst coexists with high-
excitation gas ionized by the active nucleus. The [O III] images reported
by Pogge (1988) show a high-excitation plume to the north. The ionization
map reveals a cone-shaped region of high-excitation gas aligned with the
radio jet in the north (Wilson & Ulvestad 1983). Spectroscopic studies of
the ionization mechanisms and the kinematics of the circumnuclear region
have been published by Bergeron et al. (1989) and Cecil, Bland, & Tully
(1990), among others.

41. 1997ApJ...477..631V
Re:NGC 1068
NGC 1068 is the archetypical example of Seyfert 2 galaxies with hidden
BLR visible in scattered, polarized light (see, e.g., Antonucci & Miller
1985; Bailey et al. 1988; Miller, Goodrich, & Mathews 1991). The
polarized H{beta} and H{alpha} emission lines exhibit a profile with
FWHM ~ 4500 km s^-1^. A number of attempts have already been made to
detect a broad line in Br{gamma} (Thompson, Lebofsky, & Rieke 1978; Hall
et al. 1981; DePoy 1987), Br{alpha}, and Pf{beta}{lambda}4.6525 (DePoy
1987). None of these studies have been successful in detecting infrared
emission lines that are broader than the unpolarized optical lines (FWHM
~ 1000 km s^-1^; Cecil et al. 1990; Veilleux 1991b). Our own data are
displayed in Figure 2u. No obvious broad-line emission is detected at
Br{gamma}. The Br{gamma} flux is similar to that determined by Kawara et
al. (1989) and Goldader et al. (1997). The H_2_{lambda}2.121 feature is
visible in our spectrum but at a considerably lower level than the value
measured by Moorwood & Oliva (1990) and Goldader et al. (1997). Since the
H_2_ emission is extended in this galaxy (Blietz et al. 1994),
differences in the aperture sizes and centering may explain some of this
discrepancy.
Our K-band spectrum illustrates the difficulty in trying to detect a
broad component to the infrared recombination lines of NGC 1068. The
profile of Br{gamma} is strongly affected by the underlying stellar and
dust continuum that dominates the line emission by nearly 2 orders of
magnitude. An attempt was made to subtract the stellar continuum from
these data using a spectrum of the elliptical galaxy NGC 1700 obtained
under identical conditions. The stellar continuum of NGC 1700 was found
to be a rather poor match to that of NGC 1068.
Failure to detect the BLR at infrared wavelengths implies large
extinctions, perhaps A_v_(BLR) ~> 100 (DePoy 1987). This is consistent
with the small hard X-ray luminosity of NGC 1068 (see, e.g., Awaki et al.
1991; Jourdain et al. 1994). The continuum source in NGC 1068 appears to
lie behind a thick screen of material with N_H_ > 10^24^-10^25^ cm^-2^,
and only a few percent of the total hard X-ray luminosity is scattered
into our line of sight (Miller et al. 1991; Mulchaey et al. 1992).

42. 1997A&A...319...33A
Re:NGC 1068
NGC 1068 Fig. 7 shows the wide pair across this relatively nearby Seyfert. The
X-ray sources are strong and identified with a bright BSO (C=84.5) and a very
blue BSO (C=24.2). The latter has two other BSO's at about equal distance NW
and NE of the X-ray position and it is conceivable that there are a triplet of
quasars contributing to this mean X-ray position (see appendix, Table 3).
Fig. 15 shows a more interior view of the NGC 1068 field. Table 2 shows that
the wider pair, N-S at C=9.0 and 15.7, are identified with faint BSO's. The
C=15.7 source actually has two very faint candidates about 14"S of a bright
(E=12.6 mag.) star. That star, which falls closest to the X-ray position, seems
slightly misshapen. It should be checked with spectroscopy and higher
resolution imaging. The source C=9.1 on the E side of NGC 1068 falls on at the
center of a chain of four, very faint red, non stellar objects. Opposite, on
the W side, are at least two X-ray BSO's (C=4.2 and 6.5) in a configuration
that appears to be of importance to investigate further:
The automatic plate measuring (APM) finding chart in the Appendix shows the
optical configuration in the field of the C=4.2 and 6.5 sources. The sources
with blue colors O-E=.60 and 1.20 mag. are almost certainly quasars. Of the
other blue sources the O-E=.91 is probable and the .93 and .86 sources
possible. The most outstanding feature, however is the blue (O-E=.67) galaxy
about 32"N of the C=6.5 BSO. There are indications on both the E and O Schmidt
prints of luminous filaments from this galaxy toward the two X-ray quasars.

43. 1996ApJS..105...93E
Re:NGC 1068
4.2. NGC 1068
The prototypical Seyfert 2 galaxy, NGC 1068, has been investigated extensively.
Spectropolarimetric observations (Antonucci & Miller 1985) reveal broad
Balmer-line emission associated with the nucleus, while optical
spectrophotometry (Evans & Dopita 1986) and narrow-band emission-line imaging
(Pogge 1988) reveal the presence of high-excitation gas distributed in a
conelike morphology to the northeast of the nucleus. A large system of bright
H II regions is associated with the spiral arms, and a starburst ring surrounds
the nucleus. From optical spectrophotometry of 13 giant extragalactic H II
regions located within the inner one-third of the disk, Evans & Dopita (1987)
derive a mean oxygen abundance that is slightly overabundant compared to the
solar value and find no evidence for a radial abundance gradient. H II region
abundance measurements in the inner disk by Zaritsky et al. (1994) are
consistent with zero radial gradient. The lack of a steep radial abundance
gradient may be related to the gravitational potential produced by a stellar
bar that is detected in the near-infrared (Scoville et al. 1988). Numerical
simulations by Schwarz (1981) demonstrated that such a potential tends to
produce strong radial flows into the nucleus on a timescale short compared to
the age of the galaxy.
Figure 1 reveals a ring of bright, compact H II regions ~10"-15" in radius
from the nucleus. The ring is surrounded by an agglomeration of fainter,
compact H II regions and diffuse H{alpha} emission associated with the inner
spiral arms within a radius of approximately 1'. Giant H II regions trace
spiral arm structure out to a distance of order 3' from the nucleus.

44. 1996ApJ...463..498S
Re:NGC 1068
A1. NGC 1068
Pogge (1988a) observed that the high-excitation emission is cone shaped and
lies along the radio jet observed by Wilson & Ulvestad (1982). Higher
resolution images were obtained by Macchetto et al. (1994), using FOC (not the
images presented here), which confirm the presence of the high-ionization
cone. The [O III] emission of this galaxy is extended by 7.5"(600 pc) in
PA 35^deg^. The nuclear emission has a conical shape with opening angle
45^deg^. Several condensations can be seen inside the cone. The extended
emission is coincident with the radio emission shown by Wilson & Ulvestad
(1982). The cone's base extension is 3" (240 pc). See Evans et al. (1991) for
more details about these images. See Macchetto et al. (1994) for details on
the images obtained after COSTAR.

45. 1995MNRAS.276.1262K
Re:NGC 1068
NGC 1068: Type 2. Host galaxy: Sb (UGC). Radio: although the C-array
image is resolved it does not show the famous Jet and bowshock structure
visible with A-array. The C-array flux may be in error by up to 20 per
cent as a result of a unreliable calibration source.

46. 1994CAG1..B...0000S
Re:NGC 1068
Hubble Atlas, p. 16
Sb(rs)II
H-2336-S
Nov 27/28, 1946
IIaO
10 min
NGC 1068 is the prototype for galaxies that
have a large and abrupt change of disk surface
brightness between the inner and outer regions.
Other examples include NGC 4699 (Sa or Sab;
panels 78, 87, 118, S12), NGC 4736 (RSab;
panel 1 19), and NGC 4800 (Sb; panel 188), all
shown on page 16 of the Hubble Atlas.
The inner and outer spiral pattern in
NGC 1068 is shown in the heavy print on the left,
made from the same plate used in the Hubble
Atlas. A set of very faint, external smooth spiral
structures exist far beyond the edge of the disk
shown here, but seen well in the insert print in
the Hubble Atlas (p. 16).
NGC 1068 is one of the original Seyfert
galaxies. Galaxies in the class show intense
unresolved bright nuclei (mini-quasars) and broad,
high-excitation emission lines in their nuclear
spectra (Seyfert 1943).

47. 1994CAG1..B...0000S
Re:NGC 1068
Hubble Atlas, p. 16
Sb(rs)II
PH-75-S
Dec 26/27, 1951
103aO + WG2
1 min
The very-high-surface-brightness inner
arms in this Seyfert galaxy are well seen in the
print here, made from a very-short-exposure
plate (1-minute exposure) with the Palomar
200-inch telescope. Most of the knots in the inner
arms and the two prominent knots in the much
fainter intermediate set of arms are HII regions,
as shown from an existing H{alpha} interference filter
plate, not shown.

48. 1994A&AS..108...61F
Re:IRAS 02401-0013
IRAS 0240-002 (NGC 1068). The nuclear emission lines have a FWHM of about
1200km/s, whereas the extranuclear emission is unresolved spectrally,
FWHM<200km/s.

49. 1993MNRAS.263.1023M
Re:NGC 1068
0240-00 (NGC 1068). A well-known Seyfert galaxy. Our VLA image shows a
diffuse halo surrounding a bright component with a southern extension.

50. 1993MNRAS.263..999T
Re:PKS 0240-00
0240-00 (NGC 1068). Rich, high-ionization emission-line spectrum.
Extensively discussed elsewhere.

51. 1993ApJS...86....5K
Re:NGC 1068
NGC 1068 (M 77) ; Sb, Seyfert 2.
This spectrum has a flat F_{lambda}_ is proportional to {lambda}^-0.4^)
continuum with emission lines of both low and high ionization. NGC 1068
is the nearest and brightest example of a Seyfert 2 galaxy. This highly
studied Sb galaxy was observed by Antonucci & Miller (1985) in polarized
light and found to harbor a Seyfert 1 nucleus (see Kinney et al. 1991a
for a review).
Multiple IUE spectra were combined by Snijders, Netzer, & Boksenberg
(1986), who found broad wings on the permitted emission lines and broad
emission features of Fe II. Ferland & Osterbrock (1986) and Kinney et al.
(1991a) found that the number of recombination photons measured was
larger than would be predicted based on the number of photons available
to ionize the gas. Thus the source of the UV continuum of NGC 1068
appears to be obscured from direct view.

52. 1993A&AS...97..887B
Re:NGC 1068
NGC 1068 is a well known and well studied Seyfert. CO data are taken from
Planesas et al. (1989) and converted to main beam brightness temperature
for comparison.

53. 1976RC2...C...0000d
Re:NGC 1068
= Messier 077
= 3C 071
= Arp 037
Brightest in group.
Typical class 2 Seyfert, B(nucleus) = 12.78, B_T(excluding N) = 9.70
Diameter: (Nucleus)
A.J., 73, 175, 858, 1968.
Photograph:
A.J., 73, 842, 861, 1968.
Ap. J., 151, 71, 1968.
IAU Symp. No.29, 21, 1968.
"Nuclei of Galaxies", 27, 1971.
Astrophys. Lett., 11, 21, 1972.
J.R.A.S. Canada, 68, 117, 1974.
Publ. Dept. Astr. Univ. Texas, II, 2, No. 7, 1968.
Photometry and V Isophotometry:
A.J., 73, 846, 1968.
Nuclear and Total Magnitude:
A.J., 73, 858, 1968.
Publ.Dept.A. Univ. Texas, II, 2, No. 7, 1968.
"Att...Conv. Sci. Osserv. Cima Ekar, Padova-Asiago", 101, 1973
= Cont. Asiago, No. 300b (is B(pg)):
M.N.R.A.S., 152, 79, 1971.
Photometry: (UBV)
Ap. J., 147, 394, 1967
Ap. J., 151, 71, 1968.
Ap. J. (Letters), 150, L177, 1967.
Astrophys. Lett., 1, 171, 1968
Astrophys. Lett., 11, 21, 1972.
A.J., 73, 866, 1968.
A.J., 74, 335, 1969.
Sov. A.J., 16, 763, 1973
Sov. A.J., 17, 1169, 1973.
M.N.R.A.S., 169, 357, 1974.
Soob. Spets. Ast. Obs. No. 9, 3, 1973.
Near and Far I.R. (1-300 microns):
A.J., 72, 314, 1967.
A.J., 73, 868, 1968.
A.J., 73, 870, 1968.
Sov. A.J., 12, 184, 1968.
Ap. J., 147, 394, 1968.
Ap. J., 187, 213, 1974.
Ap. J., 190, 353, 1974.
Ap. J. (Letters), 159, L165, 1970.
Ap. J. (Letters), 159, L173, 1970.
Ap. J. (Letters), 161, L207, 1970.
Ap. J. (Letters), 162, L79, 1970.
Ap. J. (Letters), 166, L45, 1971.
Ap. J. (Letters), 176, L95, 1972.
Ap. J. (Letters), 177, L21, 1972.
Ap. J. (Letters), 177, L115, 1972.
Ap. J. (Letters), 182, L89, 1973.
Ap. J. (Letters), 186, L69, 1973.
Ap. J. (Letters), 187, L109, 1974.
M.N.R.A.S., 169, 357, 1974.
Bull. A.A.S., 1, 248, 1969.
Bull. A.A.S., 5, 40, 1973.
Bull. A.A.S., 6, 448, 1974.
Ast. Tsirk. No. 557, 1970.
Nature, 233, 256, 1971.
IAU Symp. No.44, 164, 1972.
Soob. Septs. Ast. Obs. No.9, 3, 1973.
Reddening in the Nucleus:
Ap. J. (Letters), 154, L53, 1968.
Core Size at 10 microns:
Ap. J. (Letters), 186, L69, 1973.
Spectrum:
Mem. S.A. Ital., 37, 713, 1966 = Publ. Padova No. 134.
Photograph:
Astrophys. Lett., 11, 21, 1972.
Ap. J., 192, 581, 1974.
H{alpha} Line Variability:
Bull. A.A.S., 4, 231, 1972.
Ap. J., 182, 363, 1973.
J.R.A.S. Canada, 66, 71, 1972.
Astr. Tsirk. No. 688, 1972
Astr. Tsirk. No. 831, 1974.

54. 1976RC2...C...0000d
Re:NGC 1068
Internal Motions:
Ap. J., 151, 71, 1968.
IAU Symp. No.29, 21, 1968.
Spectrophotometry:
Ap. J., 141, 892, 1965.
Ap. J., 162, 743, 1970.
Ap. J., 164, 1, 1971.
Ap. J., 178, 617, 1972.
Ap. J. (Letters), 152, L165, 1968.
Ap. J. (Letters), 154, L53, 1968.
A.J., 73, 853, 1968.
Ann.Ap., 31, 569, 1968.
Astr. Ap., 1, 305, 1969.
Astr. Ap., 33, 331, 1974.
Astr. Ap., 33, 337, 1974.
Astrofizika, 1, 78, 1965.
Ast. Tsirk. No. 467, 1968.
Sov. A.J., 11, 767, 1968.
IAU Symp. No.29, 82, 1968.
"Nuclei of Galaxies", 151, 1971.
P.A.S. Japan, 24, 145, 1972.
Astrophys. Lett., 13, 165, 1973.
M.N.R.A.S., 168, 109, 1974.
Bull. A.A.S., 6, 342, 1974.
Polarization:
A.J., 70, 138, 1965
A.J., 73, 852, 1968.
Ast. Tsirk. No. 454, 1967.
Ap. J., 151, 71, 1968.
Ap. J. (Letters), 152, L165, 1968
Ap. J. (Letters), 170, L53, 1971
Ap. J. (Letters), 172, L23, 1972
Ap. J. (Letters), 173, L113, 1972
Ap. J. (Letters), 174, L127, 1972
Ap. J. (Letters), 192, L19, 1974.
Astrofizika, 4, 409, 1968.
Astrofizika, 7, 417, 1971.
Astrofizika, 8, 529, 1972.
Nature, 225, 621, 1970.
Acta Ast., 21, 311, 1971.
Bull. A.A.S., 4, 223, 1972.
Bull. A.A.S., 6, 312, 1974.
Astrophys. Lett., 12, 69, 1972.
Rotation Curve and Mass Determination:
C.R. Acad. Sc. Paris, 256, 601, 1963 = Publ.O.H.P., 6, No. 23.
J. Observateurs, 48, 247, 1965 = Publ.O.H.P., 8, No. 1
Ann. Ap., 28, 574, 1965.
HII Regions:
"Atlas and Catalogue", Univ. Washington, Seattle, 1966.
Ap. J., 194, 559, 1974.
HI 21cm:
Astr. Ap., 10, 198, 1971.
IAU Symp. No.44, 267, 1972.
Radio Observations:
Ann. Ap.26, 343, 1963.
Ap. J., 142, 106, 1965
Ap. J., 144, 216, 1966
Ap. J., 148, 367, 1967
Ap. J., 189, 399, 1974
Ap. J., 191, 305, 1974.
Ap. J. (Letters), 151, L27, 1968.
Astrophys. Lett. 8, 153, 1971.
A.J., 76, 537, 1971
A.J., 79, 903, 1974.
Astr. Ap., 25, 303, 1973
Astr. Ap., 33, 351, 1974.
Ast. Tsirk. No. 536, 1969.
Sov. A.J., 13, 881, 1970.
X-Rays: (no detection)
Ap. J. (Letters), 165, L43, 1971.

55. 1973UGC...C...0000N
Re:UGC 02188
Arp 37
(R)SA(rs)b (de Vaucouleurs), Sb- (Holmberg)
Brightest Seyfert galaxy
In Arp's class `low surface brightness companion', `small knot in arm' (Arp)
See UGC 02173

56. 1964RC1...C...0000d
Re:NGC 1068
= Messier 077
Brightest galaxy in the NGC 1068 Group.
Very bright nucleus.
Bright pseudo (r): 0.5 arcmin x 0.35 arcmin.
Peculiar (B-V) relation for type.
Photograph:
Ap. J., 97, 114, 1943.
Ap. J., 130, 26, 1959.
B.A.N., 16, 1, 1961.
Photometry:
Ap. J., 50, 384, 1919.
Ap. J., 108, 415, 1948.
B.A.N., 16, 1, 1961.
Spectrum:
Ap. J., 97, 28, 1943.
Ap. J., 130, 26, 1959.
Ap. J., 135, 732, 1962.
P.A.S.P., 53, 231, 1941.
A.J., 61, 97, 1956.
Orientation and Rotation:
Ap. J., 97, 117, 1943 = MWC 674
Ap. J., 127, 487, 1958.
Radio Emission:
Handbuch der Phys., 53, 253, 1959.
Caltech. Radio Obs., 5, 1960.
P.A.S.P., 72, 368, 1960.
Ap. J., 133, 322, 1961.
Proc. 4th Berkeley Symp., Vol.III, 285, 1960.

57. 1964ApJ...140...35M
Re:3C 071
No. 8.-Redshift from Humason, Mayall, and Sandage (1956).

58. 1961Hubbl.B...0000S
Re:NGC 1068
Messier 077
Sb
H-2336-H
Nov. 27/28, 1946
IIaO
10 min.
Enlarged 8.0X
This is the type example for galaxies with a discontinuity
of surface brightness between the inner and outer regions.
The spiral arms are not as thin as in NGC 2841, NGC 0488, NGC 7217,
NGC 5055, NGC 3521, or NGC 4699. Two principal dust arms can be
traced on this illustration. The luminous spiral arms can
be seen to within 6 sec (radius) from the center. The inner
arms are resolved into knots. This galaxy has broad
emission lines in the spectrum of the nuclear region (Seyfert,
Ap. J., 97, 28, 1943). Faint external spiral arms of
low surface brightness and amorphous texture are shown
in the insert.

59. 1961AJ.....66..562V
Re:NGC 1068
1068 Seyfert galaxy; in a small cluster.

60. 1956AJ.....61...97H
Re:NGC 1068
HMS Note No. 016
Emission spectrum (HMS Plate IVd).
Broad, bright bands studied spectrophotometrically
by Seyfert, C.K. (1943, Ap. J., 97, 28)
Apparent absence of absorption H line of Ca II, although K line is
present, is due to superposition of emission from the longward
component of the wide pair {lambda} 3868 and {lambda} 3967 of [Ne III].

61. 1918PLicO..13....9C
Re:NGC 1068
Messier 77 Ceti; Vol. VIII, Plate 7. A very bright and beautiful spiral 2.5' x
1.7' in p.a. 20^deg^. Several almost stellar condensations on the periphery of
the brighter central portions, near the bright nucleus, which is apparently not
stellar. The whorls are very compactly arranged. 11 s.n.


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