NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-05-19 T09:08:12 PDT
Help | Comment | NED Home

Notes for object NGC 4945

24 note(s) found in NED.


1. 2009ApJ...696.1218Z
Re:NGC 4945
NGC 4945. Optical emission from NGC 4945 is highly obscured. Even X-rays below
10 keV are absorbed by a column of N_H_ = 4.5 * 10^24^ cm^-2^, but NGC 4945 is
one of the brightest Seyfert galaxies at 100 keV, indicating an active nucleus
(Madejski et al. 2000). From its 1-500 keV X-ray luminosity, Madejski et al.
(2000) estimate the bolometric luminosity to be ~2 * 10^43^ erg s^-1^. The mass
of the SMBH has been determined from circumnuclear H_2_O masers to be ~1.4 *
10^6^ M_sun_, which implies that the Eddington ratio of NGC 4945 is ~0.1
(Greenhill et al. 1997).

2. 2009A&A...508..107G
Re:WMAP J1305-4928
WMAP3 J1305-4928. The WMAP source is associated with the galaxy NGC 4945, one of
the four brightest FIR sources in the sky outside the Local Group. NGC 4945
hosts both vigorous nuclear star formation (Moorwood & Oliva 1994; Spoon et al.
2000) and a peculiar broad-lined AGN with an estimated bolometric luminosity of
~60% of the nuclear FIR luminosity. We classified this object as FIR-starburst
galaxy in our sample.

3. 2006AJ....131..114B
Re:MRC 1302-491
MRC B1302-491: Edge-on spiral NGC 4945. The optical
properties have been studied in detail by de Vaucouleurs (1964),
Peterson (1980), and others.

4. 2004ApJS..151..193S
Re:NGC 4945
4.2.6. NGC 4945 NGC 4945 is one of the four brightest FIR sources in the
sky outside the local group, along with the starburst galaxies NGC 253,
M82, and M83 (Rice et al. 1988; Soifer et al. 1989), and hosts both
vigorous nuclear star formation (Moorwood & Oliva 1994; Spoon et
al. 2000) and a peculiar AGN14 with an estimated bolometric luminosity
of ~60% of the nuclear FIR luminosity (Madejski et al. 2000; Brock et
al. 1988).
The star formation is highly concentrated-HST NICMOS Pa{alpha}
observations (Marconi et al. 2000) reveal a 11" diameter (~200 pc)
star-forming disk or ring, which corresponds closely in size to the FWHM
= 12'' FIR source that emits ~50% of the 100 micron flux of the entire
galaxy (Brock et al. 1988). Moorwood & Oliva (1994) find Br{gamma}
emission confined to the central 20". This implies that the current star
formation lies within the molecular gas torus found by Bergman et
al. (1992, who argue that the CO emission comes from a ring of inner
radius ~7" and outer radius ~16"). Based on ISO spectroscopy, Spoon et
al. (2000) argue that a starburst of age >=5 x 10^6^ yr is responsible
for between 50%-100% of the nuclear region's bolometric luminosity.
Heckman et al. (1990) discovered a ~500 km s^-1^ conical outflow from
the nucleus, extending at least ~600 pc to the NW along the minor
axis. This is very similar to the starburst-driven outflow cone in NGC
253 and cannot be a conventional AGN-lit ionization cone given the lack
of [O III] emission (Moorwood et al. 1996). This H{alpha}outflow cone
(Fig. 9c) is matched by a cospatial limb-brightened X-ray outflow cone
(Fig. 9b; see also Strickland 2002; Schurch, Roberts, & Warwick
2002). Note that the local signal-to-noise maximization used in the
adaptive smoothing of the X-ray images tends to artificially reduce the
apparent limb-brightening.
On larger scales, diffuse X-ray emission associated with the
star-forming disk of NGC 4945 is apparent in Figure 9h. Indeed, the
spatial extent of diffuse X-ray emission is larger along the major axis
of the galaxy than the minor axis. There is little or no evidence for
significant extraplanar emission in other wavebands. Optical filaments
have only been traced out to ~2 kpc from the plane (Nakai 1989), and no
radio emission has been discovered (Elmouttie et al. 1997).
NGC 4945 lies at low Galactic latitude, and consequently, the foreground
H I column is high. The current lack of evidence for any larger, 10 kpc
scale, extraplanar emission, i.e., emission that might be expected from
a starburst-driven superwind, is possibly due to the resulting high
foreground optical depth of {tau} ~ 1 for H{alpha} and soft X-ray
radiation (see Table 3). The X-ray data from Chandra are further biased
against a detection of diffuse emission due to the significantly higher
than normal background experienced during this observation.

5. 2004AJ....128...16K
Re:NGC 4945
NGC 4945 (HIPASS J1305-49) is an edge-on starburst galaxy with an H I
extent of ~20' (~25 kpc). We measure an integrated H I flux density of
F_HI_ = 319+-21 Jy km s^-1^. The ATCA measurement of
F_HI_ = 70 Jy km s^-1^ by Ott et al. (2001) is severely affected by H I
absorption. Mathewson & Ford (1996) measure F_HI_ = 269 Jy km s^-1^.

6. 2004A&A...418..465L
Re:NGC 4945
NGC 4945 The 6 micron continuum is high compared to the average
starburst, but not at the level of a significant detection of the AGN
continuum given the scatter in starburst properties. The mid-IR weakness
and corresponding location in our diagrams is certainly in part due to
the foreground extinction which is high even in the mid-infrared in this
system (Spoon et al. 2000). A high resolution mid-IR image, if possible
outside the silicate band, is needed to break the ambiguity of both this
result and the low resolution mid-IR imaging of Krabbe et al. (2001),
and reach a mid-IR detection of the AGN.

7. 2003ApJS..146..249B
Re:NGC 4945
5.12. NGC 4945
In NGC 4945 we detected maser emission near the systemic velocity of
556 km s^-1^ and redshifted from systemic, between about 630 and 740
km s^-1^. Greenhill et al. (1997c) mapped the features in this source
using the subset of VLBA antennas to which NGC 4945 is accessible.
They detect blueshifted emission not seen in our spectra (and not
shown in the velocity range displayed in Fig. 1). Greenhill et al.
(1997c) find an elongated maser distribution possibly revealing a
disk. The systemic and redshifted features are separated by ~0.15 mas
(0.3 pc). One might then expect that the maser features near 556
km s^-1^ are analogous to the systemic features of NGC 4258.
Similarly, the cluster of features to the red might be associated with
the "edge" of the disk (i.e., be "high-velocity features"). Although
Gaussian fits to individual components are difficult in the redshifted
features, it is possible to trace local maser peaks throughout the
monitoring period. Drifts are negligible, as expected for
high-velocity lines. We measure drifts of 0.20 +/- 0.31, 0.16 +/-
0.31, and 0.25 +/- 0.31 km s^-1^ yr^-1^ for peaks at 705, 716, and
732 km s^-1^. The equality of the error estimates results from using
channel widths as error estimates for each individual epoch. The
strongest systemic line also shows no discernible drift. By resolving
the strong systemic peak into two Gaussian components at each epoch,
we find that those lines (centered at 553 and 555 km s^-1^) drift by
0.07 +/- 0.35 and -0.07 +/- 0.46 km s^-1^ yr^-1^. Assuming the disk
model fits, a constraint on the black hole mass can be made. Taking a
nominal upper limit for the acceleration of <0.1 km s^-1^ yr^-1^ and
rotation of 130 km s^-1^, the central black hole mass must be
>7 x 10^5^ M_solar_.

8. 2003A&A...406..505R
Re:NGC 4945
NGC 4945 is a well studied southern edge-on spiral galaxy, which
belongs to the Centaurus group. It has been studied at various
wavelengths, including the visual, IR, and radio regime. Heckman et al.
(1990) found evidence for a starburst driven superwind in NGC 4945, and
Moorwood & Olivia (1994) derive a ~400 pc size starburst in addition to
the presence of a visually absorbed Seyfert nucleus. They conclude that
NGC 4945 is in an advanced stage of evolution from a starburst to a
Seyfert galaxy. Extended emission from the disk was detected by radio
continuum observations (Harnett et al. 1989; Colbert et al. 1996a),
reaching a diameter of ~23 kpc. X-ray emission was detected from the
nuclear region, however, no extended emission was found in ROSAT PSPC
observations (Colbert et al. 1998), probably due to quite large
absorbing columns (N_H_ = 1.5x10^21^ cm^-2^), as NGC 4945 is situated
near the galactic plane (b~13deg). This decreases the sensitivity for
the soft X-ray regime.
NGC 4945 is one of the few starburst galaxies that we have included in
our H{alpha} survey, and it is no surprise that it has the second
highest L_FIR_/D^2^_25_ ratio of ~14.8 of our studied galaxies. Already
investigated by Lehnert & Heckman (1995), NGC 4945 shows strong
extraplanar DIG with many filaments protruding from the disk into the
halo. There are at least two bright filaments on either side of the
disk visible on our narrowband images. Several prominent dust patches,
which obscure some parts of the emission south of the galactic plane is
a further characteristic pattern for this galaxy. In Fig. 10 we show an
enlargement of the middle part, which nicely shows the outflow cone
from the nuclear starburst.
NGC 5290 NGC 5290 This northern edge-on galaxy is part of the LGG 361
group (Garcia 1993), which teams up with NGC 5289, which is located
~13' to the south, and has a velocity difference to NGC 5290 of ~67km
s^-1^ (Huchra et al. 1983). In the optical NGC 5290's most striking
character is a box-shaped bulge (de Souza & Dos Anjos 1987). The
L_FIR_/D^2^_25_ ratio is moderate (~2.6), and NGC 5290 shows some
extended emission, where a faint layer is detected, and some filaments,
basically coming from the nuclear region and reaching into the halo,
can be discerned (see Fig. 11). The morphology that is visible on the
H{alpha} image resembles those of a starburst galaxy, although NGC 5290
has no starburst-like FIR parameters, as the S_60_/S_100_ ratio is
considerably lower (0.31).

9. 2002ApJ...574..740T
Re:NGC 4945
NGC 4945 has a mass estimate from maser emission (Greenhill,
Moran, & Herrnstein 1997) but no reliable dispersion.

10. 2001ApJS..136...61S
Re:NGC 4945
5.24. NGC 4945
There is a debate in the literature whether NGC 4945, one of the
brightest infrared galaxies in the sky
(L_8-1000 microns_ = 2.95 x 10^10^ L_sun_; Spoon et al. 2000 and
references therein), harbors an AGN. The side taken is a strong function
of wavelength observed. Firm evidence for the presence of an AGN comes
primarily from (hard) X-ray observations. Iwasawa et al. (1993) report
the results of Ginga observations in which the 2-10 keV band has a
power-law emission spectrum with photon index ~1.7, an absorption-corrected
luminosity of 3 x 10^42^ ergs s^-1^, and strong variability on a timescale
of several hours. Similar results based on BeppoSAX observations are
presented by Guainazzi et al. (2000). Done, Madejski, & Smith (1996) use
OSSE data to determine that NGC 4945 is the second brightest Seyfert at
hard X-ray energies (the brightest being NGC 4151). Those authors aptly
note that the AGN in NGC 4945 sits behind an obscuring column of
~5 x 10^24^ cm^-2^ (Iwasawa et al. 1993), rendering it invisible at all
energies below 10 keV (see also Spoon et al. 2000). Spectroscopy at
mid-IR wavelengths with ISO (Spoon et al. 2000) suggest that at least 50%
of the bolometric luminosity of NGC 4945 derives from massive star
formation, which is heavily obscured by 36_-11_^+18^ mag of visual
extinction. Spoon et al. (2000) see no evidence from the mid-IR lines for
excitation attributable to an AGN. The starburst in this galaxy has
produced a superwind which has evacuated a cone-shaped structure,
perpendicular to the plane of the galaxy (Heckman, Armus, & Miley 1990;
Lehnert & Heckman 1996; Moorwood et al. 1996b). Quillen et al. (1999) and
Marconi et al. (2000) both present HST NICMOS imaging spectroscopy of the
1-0 S(1) line of H_2_ at 2.12 microns. The H_2_ emission is extended and
traces the inside edges of the superwind bubble (Marconi et al. 2000).
Our H_2_ line map also shows extended emission which agrees well with the
bright central emission seen by Marconi et al. (2000), though our field
of view is insufficient to trace out the full extent of the superwind
cavity. Our H_2_ flux within a 4" aperture is consistent with
1.1 x 10^-13^ ergs cm^-2^ s^-1^ observed within a 6 x 6 nuclear aperture
by Marconi et al. (2000). Our [Fe II] map shows extended bubble-like
emission similar to, but smaller in scale than, that found by
Marconi et al. (2000).

11. 2000MNRAS.318..173M
Re:NGC 4945
2.6 NGC 4945
This is the archetypal 'moderately thick' source, where the nucleus becomes
visible above about 10 keV (Iwasawa et al. 1993; Done, Madejski & Smith
1996). Modelling the BeppoSAX data (Guainazzi et al. 2000a) with the
transmission model mentioned before, a column density for the absorber of
2.2(-0.4/+0.3) x 10^24^ cm^-2^ and a power-law photon index of 1.4 +/- 0.3
are obtained. The intrinsic 2-10 keV luminosity is 3 x 10^42^ erg s^-1^.
This value differs significantly from that quoted in Iwasawa et al. (1993)
because they did not include Compton scattering in the fitting model.
Contrary to the other sources, no clear evidence is found for either
the cold or the ionized reflector, the spectrum below 8 keV being dominated
by extended, rather than nuclear, emission.

12. 1999ApJ...527..696Q
Re:NGC 4945
The lack of [O III] emission and low 3 micron (L band) flux density
suggest that a starbursting disk (rather than a low-luminosity AGN) is
responsible for the conical shaped cavity observed in the
visible/near-IR images of NGC 4945 (Moorwood et al. 1996). The cavity is
interpreted to be a region where a bipolar superwind or bubble has
evacuated denser material. Our H_2_ image resembles that of
Moorwood et al. (1996), though more structure is seen. The morphology
suggests that it forms a boundary between denser gas and a 100 pc scale
"bubble" rather than a cone. Extinction on the southern side of the
galaxy is so high at 2 micron that we would not expect to see molecular
hydrogen emission from a southern bubble or cone if it exists (see
Fig. 6).

13. 1999A&A...350....9O
Re:NGC 4945
3.4.1. NGC4945
This nearby spiral is a spectacular example of the AGN-starburst
dichotomy. At wavelengths shorter than 1 keV the object appears as a
genuine starburster and all the observational properties, including its
FIR luminosity, can be accounted for by starburst activity alone. Prior
to the X-ray observations discussed below, this galaxy was usually
classified as a starburster, a scheme which was also adopted in Paper 1.
When looked at in the X-rays, however, the galaxy becomes the perfect
example of an absorbed Seyfert 2 nucleus, i.e. powerful emission at
F proportional to {THETA}100 keV (NGC4945 is the brightest Sy2 in the
hard-X sky, Done et al. 1996) which rapidly fades at lower energies
where the AGN is also revealed by a prominent Fe-K line with an
equivalent width of ~ 1 keV. The hard X-ray luminosity and
L(100 keV)/{alpha} ratio are similar to those found in the Circinus
galaxy, a nearby Sy2 whose IRAS luminosity is fully accounted for by the
AGN alone (Oliva et al. 1999). It is therefore likely that the FIR
luminosity of NGC4945 is also dominated by the active nucleus.

14. 1997ApJS..113...23T
Re:NGC 4945
A12. NGC 4945
NGC 4945 is a nearby (z=0.002; Mauersberger et al. 1996) edge-on galaxy with a
prominent dust lane obscuring the central regions, similar to NGC 2992. It is
the third brightest galaxy in the IRAS point sourc catalog (Version 2, 1988),
and most of the IR emission originates from a compact nuclear region (Brock et
al. 1988). The source exhibits molecular emission lines (e.g., Henkel,
Whiteoak, & Mauersberger 1994), most notably an H2O megamaser (Dos Santos &
Lepine 1979). A region of extended optical lineemitting gas can be seen flowing
out from the nucleus along the galaxy minor axis (Nakai 1989; Heckman, Armus,
& Miley 1990). The X-ray spectrum reveals a highly obscured, variable hard
X-ray source pointing to the existence of a Seyfert nucleus (Iwasawa et al.
1993) in addition to the obvious contribution to X-ray spectrum from the
starburst activity which is evident in this source.
Iwasawa et al. (1993) use Ginga data to show that the active nucleus is deeply
buried behind an absorbing column of 5x10^24^ cm^-2^, which blocks the nuclear
emission below 10 keV; thus, observation in the ASCA bandpass alone does not
allow us to detect this huge absorbing column, since we see only the spectrum
of the scattered nuclear continuum plus contributions from the host galaxy, and
without the higher energy data we would have a misleading picture of this
source. Done, Madejski, & Smith (1996) use the combined Ginga, ASCA, and OSSE
data to confirm the prediction from the Ginga spectrum that NGC 4945 is one of
the brightest Seyfert galaxies in the sky at hard X-ray energies, second only
to NGC 4151.
The ROSAT PSPC data reveal several point sources close to the nucleus and
probably associated with the host galaxy, as well as diffuse emission of ~10'
extent, coincident with the optical image of the galaxy (Brandt, Iwasaw, &
Reynolds 1996). In Table 4, we do not list serendipitous point sources as it is
difficult to deconvolve those from the extended emission evident in the ASCA
image. Useful positions and time variability information were obtained by
Brandt et al. (1996) for sources close to the active nucleus.

15. 1997A&A...319...33A
Re:NGC 4945
NGC 4945 The Seyfert is one of the bright galaxies along the line of the radio
jets emerging from Cen A (Arp 1968b; 1994a). Since it is at the same distance
as Cen A its X-ray sources give the same kind of log N-log S relation as shown
in Fig. 1b of Radecke. There are no strong pairs within the PSPC field and the
inner sources are strong and distributed along the projected major axis roughly
NE-SW. Because these sources are in or near the optical extent of the galaxy,
identifications have not been attempted here.

16. 1996ApJS..105...75C
Re:NGC 4945
4.1.11. NGC4945
This Seyfert galaxy also houses a strong nuclear starburst. The presence of a
superwind in this galaxy has been discussed in detail by Heckman et al. (1990),
who argue that the wind is driven by the starburst. Harnett et al. (1989)
present images of a radio halo in this galaxy, presumably produced by the wind.

17. 1996ApJ...467..551C
Re:NGC 4945
3.1.14. NGC 4945
The large-scale 4.75 GHz map from Harnett et al. (1989) is reproduced in Figure
1j. The extraplanar structure in NGC 4945 extends ~10' (20 kpc) along the minor
axis on both sides of the disk.

18. 1994CAG1..B...0000S
Re:NGC 4945
Sc
CD-144-S
Feb 1/2, 1978
103aO + GG385
30 min
NGC 4945 is seen nearly edge on, hiding the
spiral pattern. The heavy dust on the near side,
silhouetted against the background disk,
obscures whatever nucleus may be present, but it
is certain that there is no central bulge and that
the nuclear region is small.
No useful resolution into individual stars is
achieved on the available plate material.
Although individual stars can be identified in parts
of the arms, peeking out of the dust, they are
much fainter than in NGC 247, which has nearly
the same redshift. Contamination by Galactic
stars is also a problem at the low galactic latitude
of b = 13^deg^.
The redshift of NGC 4945 is small, v_o = 275 km/s.
Closeness is also indicated by the large
angular size (D_25_ = 20'), consistent with the small
redshift. Although the distance is evidently small,
the high inclination and the dust obscuration
prevent NGC 4945 from being useful for the
calibration of distance indicators normally used
for measurements of extragalactic distances.

19. 1992ApJS...80..137J
Re:MRC 1302-492
Core-halo source with the halo elongated
(the nucleus and disk of an edge-on spiral, see below). The MOST image
is the average of two observations, to increase the dynamic range. Model
fitted by Ekers (1969) and mapped by Cameron (1971), Harnett & Reynolds
(1985) and Whiteoak & Bunton (1985).
.
Edge-on spiral galaxy, NGC 4945, 9.3 m at 13 02 31 -49 12 12
(Lauberts 1982),
see Mills et al. (1960). z = 0.0018, Burbidge & Burbidge (1972).

20. 1985SGC...C...0000C
Re:NGC 4945
Plate 2247
Very patchy, many stars superposed. Small SB(s)m 6.5 north-preceding.

21. 1982ESOU..C...0000L
Re:ESO 130231-4912.2
=ESO 219- G 24
prominent in group

22. 1979AJ.....84..472S
Re:NGC 4945
Generally amorphous with much dust throughout the central disk.
No useful resolution into stars.
There are several candidates for resolved HII regions
at the 3 arcsec level.
Search for Cepheids not likely to be useful.

23. 1976RC2...C...0000d
Re:NGC 4945
= PKS 1302-49
Description and Precise Coordinates:
Observatory, 87, 169, 1967.
Vistas in Ast., Vol. 14, 210, 1972.
Photograph:
Ap. J., 139, 899, 1964.
Observatory, 87, 169, 1967.
Photometry:
Ap. J., 139, 899, 1964.
Atlas Gal.Austr., 1968.
Spectrum:
Ap. J., 172, 37, 1972.
Discordant velocity Source N1 (A.J., 72, 821, 1967) rejected.
Spectrophotometry: Molecular Absorption: OH, H_2CO
IAU Circ. No. 2552, 1973.
Astrophys. Lett., 15, 211, 1973.
Nature, 247, 526, 1974.
Dynamics and Mass Determination:
Ap. J., 139, 899, 1964.
Interferometry H{alpha}:
Bol. A. A. Argentina, No. 14, 90, 1968.
Astr. Ap., 12, 379, 1971.
HI 21cm (absorption):
Astrophys. Lett., 15, 211, 1973.
Radio Observations:
Australian J. Phys., 16, 360, 1963.
M.N.R.A.S., 152, 439, 1971.

24. 1964RC1...C...0000d
Re:NGC 4945
A large late-type spiral partly obscured at a low galactic latitude.
Note correction of -12 arcmin to NGC declination (R. Shobbrok, Mt. Stromlo,
unpublished)
See also M.N.R.A.S., 81, 601, 1921.
HA 88, 2 dimensions (11.5 arcmin x 2.0 arcmin, series a') are for the bright
part only.
Photograph:
Occ. Notes R.A.S., 3, No. 18, 1956.
Orientation:
Ap. J., 127, 487, 1958.
Radio Emission:
Handbuch der Phys., 53, 253, 1959.
Observatory, 83, 20, 1963.


Back to NED Home