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Notes for object NGC 0891

26 note(s) found in NED.


1. 2007A&A...468..129T
Re:NGC 0891
4.2.1 NGC 891
Optical imaging shows that this source has an edge-on orientation. This may be
one reason why, as can be seen in Fig. 1, there is no candidate X-ray
counterpart in the ACIS field corresponding to this source. Accordingly, the
flux and luminosity values in Table 2 are upper limits, and we do not discuss
this source any further.

2. 2005MNRAS.358..481K
Re:NGC 0891
NGC 891. Parallel to the major axis. The transparent model provides a good
match, except for the outermost bins. Taking a rotation curve which does not
have the inner maximum but instead is 'solid body' up to 60 arcsec does not
significantly affect the results.
Perpendicular to the major axis.Fig. 7 shows the best-fitting dusty model,
obtained using only the data at z>=h_z_. This model is consistent with that
determined from the parallel slit position. At and above z=h_z_ dust extinction
is clearly unimportant. Remarkably, the model also provides a good match to the
velocity dispersions below h_z_. This shows that the drop in the observed
stellar velocity and dispersion below one stellar scaleheight is very likely to
be due to dust extinction. At low z the predicted stellar velocities of the
dusty model are too low. This may indicate that a smooth dust model
overestimates the effect of extinction on the velocity. Interestingly, the
position of the minimum in the line-of-sight projected velocity and dispersion
is very sensitive to the inclination. The adopted inclination, i= 89.8 +/-
0.5{degree}, is based on model comparisons at various inclinations (dotted
lines, for i< 90 the far side is to the northwest).

3. 2005ApJS..157...59L
Re:NGC 0891
NGC 891 is an edge-on Sb galaxy at a distance of 8.36 Mpc. ULX1 is close to but
not the nucleus and on the edge of the dust lane. ULX2 is on the dust lane and
is identified as SN 1986J. ULX3 (IXO 3) is on the tip of the dust lane and
showed a steady luminosity increase from 1.4 x 10^39^ to^ ^2.4 x 10^39^ ergs
s^-1^ in 3 years.

4. 2004MNRAS.352..787K
Re:NGC 0891
NGC 891. For NGC 891 a different approach was taken in order to minimize
the influence of the probable absorption. Here, each velocity profile
was fitted separately, such that once the circular velocity is
determined at a certain radius it is kept fixed in each of the remaining
fits. This ensures that the fit is less susceptible to absorption
because the inner part of the XV diagram, where the absorption is
probably highest, no longer influences the determination of rotational
velocities at larger radii. The resulting fit matches the
extreme-velocity envelope very well. The amplitude of the rotation curve
is approximately 225 km s^1^, in agreement with previous H i studies
(Sancisi & Allen 1979; Rupen 1991). The inner maximum is in agreement
with the CO measurements (Sofue 1996). The decline of the rotational
velocity at the onset of the southern extension (R~+300 arcsec) is much
more gradual than it appears from the lowest contour. This is caused by
the sharp drop in H i surface density at that radius.

5. 2004MNRAS.352..787K
Re:NGC 0891
NGC 891. For NGC 891 a different approach was taken in order to minimize
the influence of the probable absorption. Here, each velocity profile
was fitted separately, such that once the circular velocity is
determined at a certain radius it is kept fixed in each of the remaining
fits. This ensures that the fit is less susceptible to absorption
because the inner part of the XV diagram, where the absorption is
probably highest, no longer influences the determination of rotational
velocities at larger radii. The resulting fit matches the
extreme-velocity envelope very well. The amplitude of the rotation curve
is approximately 225 km s^1^, in agreement with previous H i studies
(Sancisi & Allen 1979; Rupen 1991). The inner maximum is in agreement
with the CO measurements (Sofue 1996). The decline of the rotational
velocity at the onset of the southern extension (R~+300 arcsec) is much
more gradual than it appears from the lowest contour. This is caused by
the sharp drop in H i surface density at that radius.

6. 2004MNRAS.351.1247K
Re:NGC 0891
NGC 891. The slit positioned perpendicular to the major axis indicates
that the kinematics are rather symmetric with respect to the galactic
plane (z= 0). Both the velocities and velocity dispersions show a clear
drop below z = hz with minima at z= 0. This behaviour is probably caused
by dust attenuation. A high optical depth near the plane would largely
hide the region at the line of nodes (the intersection of the galaxy
plane and the plane of the sky). Only the outskirts of the stellar disc
nearer to the observer, which are expected to have small projected
velocities and velocity dispersions, still contribute to the
LOSVD. Above the strong dust lane (z >= hz ), the stellar velocities and
dispersions remain constant with z up to =2.5 hz . The slit positioned
parallel to the major axis reveals a steady radial decrease of the
velocity dispersion. In addition, several small-scale irregularities in
the stellar velocity and dispersion are apparent, for instance at R=-110
arcsec. These irregularities can be traced to distinct dust patches in
the optical image. The h_3_ parameter reveals a high-velocity tail in
the LOSVD for radii up to 50 arcsec. The h_4_ parameter seems to
indicate that the LOSVD is more peaked than Gaussian in this region.

7. 2004ApJS..151..193S
Re:NGC 0891
4.2.9. NGC 891 NGC 891 is a spiral galaxy very similar in size, total
luminosity, spiral type, and molecular gas spatial distribution to the
Milky Way, seen almost exactly edge-on (van der Kruit 1984; Scoville et
al. 1993). Despite these similarities, NGC 891 is forming stars more
intensely than the Milky Way, as it is twice as rich in molecular gas
(Scoville et al. 1993), twice as IR-luminous as the Milky Way
(Wainscoat, de Jong, & Wesselius 1987), and several times more
radio-luminous at 1.4 GHz (Allen, Baldwin, & Sancisi 1978). The IRAS
f60/f100 ratio for NGC 891 is higher than that of the Milky Way (0.31
for NGC 891 vs. ~0.2 for the Milky Way; see Rice et al. 1988 and
Boulanger & Perault 1988).
There is no direct evidence for a weak AGN in NGC 891, although the
Chandra observations do show a weak hard X-ray source (see Figs. 12a and
12d) ~3" to SW of the position of the radio continuum point source we
have adopted as the nucleus (Rupen 1991). Given the ~2" positional
uncertainty associated with the radio source, the X-ray source may be
associated with it.
Little is known about the star formation rate in the nucleus of NGC
891-optically the region is highly obscured by the prominent dust lane
bisecting much of the disk. Diffuse X-ray emission within the central
few kiloparsecs is faint, with a surface brightness 1 to 1.5 orders of
magnitude fainter than in the starburst galaxies such as M82, NGC 1482,
and NGC 3079. In the 0.3-1.0 keV energy band the presence of the dust
lane is obvious (although not immediately apparent in Fig. 12b) and
forms the basis of the X-ray shadowing experiment performed by Bregman &
Irwin (2002).
NGC 891 has a radio (Allen et al. 1978), H{alpha}(Rand, Kulkarni, &
Hester 1990; Dettmar 1990; Hoopes et al. 1999), H I (Swaters, Sancisi, &
van der Hulst 1997), and X-ray halo, all of which extend to heights ~5
kpc above the plane of the galaxy. Dense dust clouds and filaments have
been traced to heights of |z| ~ 2 kpc (Howk & Savage 1999,
2000). Diffuse X-ray emission in the halo of NGC 891 was discovered in
ROSAT PSPC observations (Bregman & Pildis 1994; Bregman & Houck 1997),
and it is currently the only normal spiral galaxy around which
extraplanar diffuse X-ray emission has been detected.

8. 2004ApJS..151..193S
Re:NGC 0891
Star formation, as traced by 50 micron IR emission (Wainscoat et
al. 1987),nonthermal radio emission (Rupen et al. 1987), and H{alpha}
emission (e.g., Hoopes et al. 1999), is not uniformly distributed
throughout the disk of NGC 891. Star formation activity appears stronger
along the major axis to the northeast of the nucleus than along the
major axis to the southwest of nucleus. The distribution of extraplanar
H{alpha} and soft X-ray emission is similarly asymmetric with respect to
the nucleus, emission being strongest above the region of the disk to
the northeast of nucleus (Figs. 12h and 12i). This strongly suggests
that the extraplanar H{alpha} and soft X-ray is created by star
formation processes within the disk, as opposed to some form of
accretion scenario (Toft et al. 2002; Sommer-Larsen et
al. 2003). Diffuse halo X-ray emission extends along the plane of the
galaxy ~150" to the NE, and ~90" to the SW, of the nucleus (r ~ 7 kpc
and r ~ 4.2 kpc, respectively), and it appears to reach a height of ~90"
above and below the plane of the galaxy over most of this region.
As in the case of NGC 4631, both the X-ray and H{alpha} emission appear
relatively smooth and spatially uniform, although H{alpha} observations
do show a variety of vertical filaments reaching heights of ~1.5 kpc
above the plane (e.g., Howk & Savage 2000).
Note also that the diffuse X-ray emission is particularly intense and
has its greatest vertical extent, above (to the NW of) the nucleus
(Fig. 12h), extending ~140" (z ~ 6.5 kpc) from the nucleus. This
suggests significant nuclear star formation is occurring in this region
(perhaps associated with the ~15"-radius [~700 pc] bar seen in CO
emission; see Garcia-Burillo & Guelin 1995).

9. 2003ApJS..148..383M
Re:NGC 0891
A3. NGC 891 The H{alpha} and [N II] images of NGC 891 obtained with the
TTF on the WHT are presented in Figure 3. As mentioned in Table 4, our
image of NGC 891 is contaminated by a few poorly subtracted foreground
stars and reflective ghost images. Nevertheless, the data clearly show
a dust lane that intersects the galaxy and diffuse emission extending
over a broad range of radii and up to heights on the order of 2 kpc.
The H{alpha} luminosity /D^2^_25_ ratio for this galaxy is ~1.1 x 10^17^
ergs s^-1^ kpc-^2^. A scale height of 1.0 kpc was measured for both
halos, slightly smaller than the value derived by Rand et al. (1990; 1.2
kpc) using a disk+bulge+halo decomposition, but larger than the value
obtained by Dettmar (1990; 0.5 kpc) using a one-exponential fit. The
total ionized mass of extraplanar material is estimated at 1.4 x 10^8^
M_{sun}_. On the basis of the portion of NGC 891 that we were able to
analyze, we find little filamentary emission, but rather widespread,
diffuse emission above the disk.
The line ratio map shown in Figure 3 is affected by reflective ghosts
but clearly shows the presence of a positive vertical [N II]/H{alpha}
gradient in this object, in agreement with results of long-slit studies
(e.g., Keppel et al. 1991; Dettmar & Schultz 1992; Rand 1998, 2000).

10. 2002AJ....124..675C
Re:UGC 01831
Very large galaxy. Flux density from Condon (1987)

11. 2001ApJS..132..129M
Re:NGC 0891
NGC 891. - As one of the nearest edge-on systems, NGC 891 has been used
to explore the vertical structure of galaxy disks (e.g., Morrison et al.
1997). It is unusual in showing bright diffuse H{alpha} emission out to
more than 4 kpc from the plane of the galaxy (Rand, Kulkarni, & Hester
1990), and deep continuum images show dust filaments extending out half
that distance (Howk & Savage 1997).
The MUV image is underexposed (Fig. 23a). It shows a faint, spatially
resolved linear structure coincident with the midplane of the galaxy. The
UV light is most likely produced by stellar associations in the outer disk
of the galaxy and by scattering of light from the inner disk by the
extended dust. In the FUV (not shown), only very faint extended emission
is observed.

12. 1999ApJ...522..669H
Re:NGC 0891
In Figure 1 we show both the Schmidt and the 0.9 m continuum-subtracted
H{alpha} images of NGC 891. Vertically extended emission is clearly
present. The DIG layer can be traced to more than 3 kpc away from the
plane in these figures. The emission seems fairly uniform but does
appear brighter and more extended near two large H II regions on the
east side of the disk. In the higher resolution 0.9 m image, the
extraplanar emission begins to show filamentary structure, although it
is not as pronounced as in NGC 4631 (see below). There is a correlation
with the brightest star-forming regions, with the brightest DIG near
bright H II regions in the inner disk. Rand (1997a) noted that the
bright filaments almost always connect to an H II region in the disk.

13. 1999AJ....118.2331V
Re:NGC 0891
This SN II belongs to a peculiar class, known as SNe IIn (Schlegel
1990), which show narrow emission profiles atop broader bases in their
spectra, particularly at H{alpha}, possibly arising from the SN shock
interacting with very dense circumstellar matter. SN 1986J was first
discovered in the radio and subsequently followed optically (Rupen, van
Gorkom, & Gunn 1987; Leibundgut et al. 1991); it was missed in optical
SN searches near the time of explosion. The SN is a very luminous radio
source (Weiler, Panagia, & Sramek 1990) and should also still be a
luminous optical emission-line source. Weiler et al. (1990) provide an
accurate radio position for the SN, but, unfortunately, the coordinates
for the pair of short-exposure F606W archival images of NGC 891 are
greatly in error. We located the SN site on the coadded image pair using
a finding chart for SN 1986J (Rupen et al. 1987). A star is seen in
Figure 4 with m_F606W_ = 21.28 +/- 0.06 mag on 1994 December 1, which
corresponds to the same object seen in the Rupen et al. image and is
therefore almost certainly the SN. Only faint, diffuse emission is
visible around the SN, so it is not possible to study any associated
stellar population.

14. 1996ApJS..103...81C
Re:NGC 0891
NGC 0891.--The 1418 MHz VLA B-configuration map of Rupen et al. (1987) first
showed SN 1986J. VLA polarization maps in Hummel, Beck, & Dahlem (1991) and
in Sukumar & Allen (1991).

15. 1996ApJ...458..120S
Re:NGC 0891
NGC 891
This edge-on Sb galaxy at a distance of 8.9 Mpc has been extensively observed
in the CO line using the IRAM 30 m telescope (Garcia-Burillo et al. 1992), the
NRO 45 m telescope(Sofue & Nakai 1993), and the Owens Valley Radio Observatory
(OVRO) interterometer (Scoville et al. 1993). It has been mapped in the H I
line (Sancisi 1976a; Rupen 1991) at a comparable resolution to the CO
observations. In Figure 1 we show a composite PV diagram of the CO and H I
lines reproduced from Sofue et al. (1994). The CO diagram is characterized by
the 4 kpc molecular ring and the high-velocity nuclear disk at R < 1 kpc. The
H I gas is distributed in a broad ring and outskirts at R > 10 kpc. For
deriving the rotation curve near the nucleus, we also made use of the IRAM CO
(J = 2-1) observation at a 13" resolution (Garcia-Burillo et al. 1992) and the
higher resolution PV diagram obtained by interterometer observations by
Scoville et al. (1993).
The obtained rotation curve is given in Figure 4. After a steep rise near the
nucleus, the rotation velocity attains a steep maximum over 250 km s^-1^,
followed by a dip at R = 2 kpc. Then it becomes almost flat at R ~ 3 kpc and
remains so until R ~ 15 kpc. Beyond this radius, the rotation velocity
gradually declines toward the outermost region. The rotation curve is very
similar to that of our Galaxy (Fig. 11).

16. 1995ApJS...98..477H
Re:NGC 0891
H{beta} emission is marginally visible in the blue spectrum, despite the
presence of fairly prominent H{alpha} emission in the red spectrum. The
steep Balmer decrement, and the implied large reddening, undoubtedly
reflects the conspicuous dust lane seen in this edge-on galaxy. No
obvious nucleus was visible, and the spectra were extracted from the
geometrical center of the dust lane. Pildis, Bregman, & Schombert (1994)
discuss the extensive system of gas above and below the plane of NGC 891.

17. 1995A&A...302..691D
Re:NGC 0891
This galaxy was investigated by Hummel et al. (1991a,b) in great detail
at {lambda}{lambda}21, 49, and 90cm and by Sukumar & Allen (1991) at
{lambda} 6cm. While the latter authors dealt mainly with the
polarized emission, Hummel et al. (1991a) constructed a two-component
model for the total emission (as already done by Allen et al. 1978). For
the extended "thick disk" they found a "Peanut"-shaped morphology on the
eastern side and an extension of the radio emission towards the
southwest.
In our {lambda}2.8 cm map the intensity peak is located about 1'
southwest of the nucleus of the galaxy and is partly due to the emission
of SN 1986J. After subtraction of this source we find a morphology
similar to that at longer wavelengths. Only the southwestern extension
detected by Hummel et al. (1991a) cannot be seen in our map, which might
be an indication of a spectral steepening in this region.
Linearly polarized emission could also be detected in NGC 891, mainly
northwest of the major axis. The observed magnetic field orientation is
predominantly parallel to the plane, with small deviations in the
southern half: here the magnetic field lines seem to tilt away from the
galactic plane.

18. 1994CAG1..B...0000S
Re:NGC 0891
Sb(on edge)
Hubble Atlas, p. 25
PH-208-S
Nov 10/11, 1952
103aO + WG2
30 min
NGC 891 is seen almost exactly edge on.
The dust lane cuts centrally across the small
central bulge. The intricate distribution of the
dust out of the plane can be particularly well
traced because of the very nearly edge-on
orientation.
A definitive discussion and analysis of the
luminosity distribution perpendicular to the
plane is given by van der Kruit and Searle
(1981).

19. 1993A&AS...97..887B
Re:NGC 0891
NGC 891 will be discussed by Garcia-Burillo et al. (1992).

20. 1989AJ.....98..419V
Re:B3 0219+421
Nucleus of NGC 891; the fluxes are unreliable at both frequencies.

21. 1976RC2...C...0000d
Re:NGC 0891
In the NGC 1023 Group.
Dimensions and Isodensitometry:
A.J., 79, 671, 1974.
Spectrum:
Old HMS velocity (+246 km/sec, Source B) rejected. See 21cm references.
HI 21cm:
Astr. Ap. 28, 96, 1973.
Astr. Ap. 33, 451, 1974.
Radio Observations:
M.N.R.A.S., 161, 127, 1973.
Astr. Ap. 31, 447, 1974.

22. 1973UGC...C...0000N
Re:UGC 01831
SA(s)? (de Vaucouleurs), Sb+ (Holmberg)

23. 1964RC1...C...0000d
Re:NGC 0891
In the NGC 1023 Group.
Photograph:
Handbuch der Ap., 5, 2, 843, 1933.
Photometry:
Ap. J., 91, 539, 1940.
Medd. Lund II, 114, 1945.
Medd. Lund II, 128, 1950.
A.J., 56, 89, 1951.
HII Regions:
Zeit. fur Ap., 50, 168, 1960.
Radio Emission:
Handbuch der Phys., 53, 253, 1959.
P.A.S.P., 72, 368, 1960.

24. 1961Hubbl.B...0000S
Re:NGC 0891
Sb
PH-208-S
Nov. 10/11, 1952
103aO + WG2
30 min
Enlarged 1.2X
The nuclear bulge in NGC 0891 is smaller than that in NGC 4565.
The galaxy is classed as late Sb. The dust lane has a very
intricate pattern perpendicular to the plane. Thin fingers
of obscuration extend at least 30 sec of arc in the Z direction.
The distance modulus of NGC 0891 is about (m-M) = 29.0,
assuming membership in the NGC 1023 kinematical
group (Humason et al., A. J., 61, 97, 1956, Table XI) and
a Hubble constant of 75 km/sec/Mpc. At this distance,
30 sec of arc corresponds to 105 parsecs. Energy
must be pumped into the dust to keep it distended this far
above the plane against the potential energy of the
gravitational field. It is believed that NGC 0891 is similar to
our own galaxy. See the photograph of the dust band in the
plane of our galaxy compared with NGC 0891 by Osterbrock
and Sharpless (Ap. J., 115, 140, 1952). See also the infrared
photographs of Code and Houck, Ap. J., 121, 533, 1955.

25. 1957HPh....53..275d
Re:NGC 0891
SA(s:)b(sp)
(Plate 46)
This edge-on view of a typical ordinary spiral is for
comparison with NGC 4215 (Plate 43) and NGC 4710 (Plate 44).
Note how the dark material, limited to a ring close to the
nucleus in the lenticulars, spreads to the whole of the
intermediate and outer parts of the spiral patter.
Compare also with NGC 4594 (Plate 39), and NGC 4244 (Plate 42).

26. 1918PLicO..13....9C
Re:NGC 0891
Vol. VIII, Plate 6. This beautiful example of an edgewise spiral with an
absorbing lane down its center is 12' x 1' in p.a. 24^deg^. Rather bright. See
Abs. Eff. 54 s.n.


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