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Notes for object NGC 7331

30 note(s) found in NED.


1. 2012ApJ...754...67F
Re:NGC 7331
NGC 7331 .SAS3..-The HST F555W image shows several dust lanes in the bulge
region. However these do not imply any sense of rotation and seem to be overlaid
on a generally smooth light distribution. Fisher & Drory (2008) admit that the
high inclination leaves the classification as classical bulge questionable. Here
we label it as nonclassified. The rotational velocity profile is already
flattened at the bulge radius of r_b_ = 26". The velocity dispersion rises from
about 75 km s^-1^ in the disk to 125 km s^-1^ in the center. The dispersion
profile has two steps or shoulders at ~= +/- 20". The h_3_ moments are generally
anti-correlated with velocity and reach a local maximum of about +/- 0.15 at r =
15". Also the h_4_ moments reach local maxima with values of up to 0.15 in the
same radial range. These large moments are a consequence of the double-peak
structure of the LOSVDs caused by a counter-rotating kinematic component
discovered by Prada et al. (1996; see Section 5.7).

2. 2009A&A...503..409H
Re:NGC 7331
The bright inner disk of this highly inclined spiral disk is highly polarized,
and polarization is also detected in the outer disk on both sides of the minor
axis, extending well out into the low surface brightness outer disk. The
polarized fraction is quite low in the inner parts, at about 1-3%, but it
increases rapidly toward the outer parts up to about 20-40%. This is a galaxy in
which multiple Faraday depth components are encountered along some
lines-of-sight, implying large-scale interspersal of emitting and rotating
media. Magnetic field orientations of the single brightest polarized component
along each line-of-sight show some tendency to be aligned with the star-forming
disk at small radii, but become increasingly radial in the minor axis
extensions. The peak Faraday depth distribution is bi-modal, with two dominant
ranges occurring, one near {phi} = 0 rad m^-2^ in the inner disk and the other
near -150 rad m^-2^ associated with the minor axis structures. The Galactic
foreground RM in this general di rection is known to be quite extreme (cf. Han &
Qiao 1994; Broten et al. 1988), even at tens of degrees from the Galactic plane.
The brighter lobes of two resolved double sources in the field suggest a value
of about -177 +/- 7 rad m^-2^. As was the case for NGC 6946, the relatively low
Galactic latitude (b = -21^deg^) increases the likelihood of fluctuations in the
foreground RM. This is reflected in the larger scatter of RM values of even the
most reliable of probes.

3. 2008AJ....136.2648D
Re:NGC 7331
4.16. NGC 7331 is an early-type Sb spiral with prominent spiral arms. It was
previously observed in H I by Begeman (1987). Figure 19 compares both curves. It
is clear that the two curves broadly agree, but there are many small
differences. Most of them can be attributed to the very different spatial and
velocity resolutions and different choices for the inclination distribution (see
discussion in the Appendix). Note that the inner eight points of the Begeman
(1987) curve are based on position-velocity diagrams and not on a tilted-ring
fit to a velocity field. The differences in the outermost parts are due to the
different inclinations used there.

4. 2008AJ....136.2648D
Re:NGC 7331
6.14. NGC 7331 The surface brightness profiles of NGC 7331 are shown in Figure
51. The 2MASS J, H, and K profiles can be traced out to ~265"; the 3.6 {mu}m
profile can be traced out to 350", or the entire extent of the H i disk. The
profiles show clear evidence for a compact central component. We modeled this
component as an exponential disk with parameters {mu}_0_ = 12.0 mag arcsec^-2^
and h = 0.32 kpc. For the outer disk we simply used the observed profile with
the inner component subtracted, as indicated in Figure 51. NGC 7331 has a
well-defined color gradient, and shows some of the largest {GAMMA}^3.6^_*_
values, as well as one of the steepest {GAMMA}^3.6^_*_ gradients in the entire
sample. Beyond the radii where the 2MASS colors could be reliably determined, we
assume a constant value of {GAMMA}^3.6^_*_ = 0.7. These high {GAMMA}^3.6^_*_
values lead to incompatible mass models: using the predicted {GAMMA}^3.6^_*_
values results in disks that are too massive. This is shown in Figure 52,
clearly suggesting that for this galaxy, the color-based values are not correct
(for that reason we do not list the model parameters in Tables 3-6). Leaving
{GAMMA}^3.6^_*_ free in the fit, the data clearly prefer lower values. A
possible explanation could be the presence of a strong dust ring in the inner
disk of NGC 7331 (Regan et al. 2004). The radius at which this ring is found
corresponds to the radius where the highest {GAMMA}^3.6^_*_ values are found.
This would suggest that the very inner {GAMMA}^3.6^_*_ maximum and steep drop
are associated with the central component, whereas the subsequent steep rise and
gradual drop are associated with the dust ring, and therefore do not reflect
stellar population changes. We therefore also investigate a model where the two
components each have a radially constant {GAMMA}^3.6^_*_. Using Figure 51, we
find that {GAMMA}^3.6^_*_ = 1.0 and {GAMMA}^3.6^_*_ = 0.7 are good estimates for
the inner and outer disks, respectively. These fits are presented in Figure 53.
We then find that both ISO and NFW models result in better fits. NGC 7331 is
therefore the one galaxy in our sample where the (J - K)-{GAMMA}^3.6^_*_
relation clearly fails. Note that for the fixed {GAMMA}^3.6^_*_ case, the Kroupa
models yield much better fits than the diet Salpeter ones.

5. 2006MNRAS.366.1265B
Re:NGC 7331
The receding part of the galaxy is invisible in the RV maps presented in this
paper. It was first thought that this part of the galaxy was out of the
interference filter, but this feature has also been observed by Marcelin et al.
(1994). An a posteriori scan of the interference filter used showed that the
galaxy should have been well centred in the filter. Deep H{alpha} images taken
by Regan et al. (2004) at the KPNO 2.1-m telescope show the same asymmetric
emission pattern. However, Regan et al. (2004) also made Pa{alpha} observations
and did not observe that asymmetry. A theory to explain this is that a ring of
dust located south of the centre of the galaxy is blocking the H{alpha} emission
from reaching us whilst letting the Pa{alpha} through. This galaxy has been
called "Post-starburst" by Tosaki & Shioya (1997) who studied its kinematics in
CO. CO data have also been gathered by Nishiyama et al. (2001).

6. 2006ApJ...647..140F
Re:NGC 7331
This galaxy (T2, Sb) has three point sources, but none are at the center (at the
3 {sigma} confidence level). There is no hard X-ray emission close to the center
of the galaxy. No source had enough counts to justify spectral fits. The stellar
population does not have a young component and is mostly 1-10 Gyr old (Cid
Fernandes et al. 2004, 2005; Gonzalez Delgado et al. 2004). Hence, this LINER
might be powered by stellar processes, most likely associated with the old
stellar population.

7. 2006A&A...460...45G
Re:NGC 7331
NGC 7331 (UGC 12113). Stockdale et al. (1998) and Roberts & Warwicl (2000) used
ROSAT data to point out the AGN nature of this galaxy. Nevertheless, the hard
X-ray data from Chandra do not show any evidence of a nuclear source, being very
diffuse at high energies (Fig. 5). Note that Filho et al. (2004) describe this
galaxy as hosting a hard (2-10 keV) X-ray nucleus, but Satyapal et al. (2004)
class it as an object exhibiting multiple, hard off-nuclear point sources of
comparable brightness to the nuclear source. Our estimated parameters are
consistent with a spectral index of 2-2.6 and temperature of 0.7 keV. Gallo et
al. (2006) present XMM-Newton data on the source and find that the spectrum is
consistent with a thermal component at kT = 0.49 keV plus a power law with
{GAMMA} = 1.79 giving a luminosity that it is a factor of 10 larger than our
estimation. The reasons for this difference are not clear. The estimation of the
luminosity by Satyapal et al. (2004) for an intrinsic power slope of 1.8 is in
perfe ct agreement with ours, hinting that resolution effects are important to
explain the difference with the work by Gallo et al. (2006).

8. 2004A&A...418..429F
Re:NGC 7331
NGC 7331 The Chandra soft X-ray image of this galaxy shows several
blotchy regions of emission, along about 3', in a North-South direction,
similar to the morphology of the optical galaxy and also the radio
(Cowan et al. 1994). Previous observations with ROSAT (Stockdale et
al. 1998) have detected a luminous X-ray nucleus (few 10^40^ erg s^-1^). The
Chandra observation has resolved the ROSAT emission into several X-ray
sources and revealed a hard X-ray nucleus positionally coincident with
the radio core detected in Cowan et al. (1994). The spectrum of the
nuclear source is fit with a one component power law ({GAMMA}=1.46)
model and the luminosity is two magnitudes lower (~10^38^ erg s^-1^) than
the ROSAT value.

9. 2003AJ....126..742H
Re:NGC 7331
The morphological classification as determined by us is indicated in
parentheses next to the galaxy name, with our "chaotic circumnuclear
dust" (C) category now not including those galaxies with obvious dust
lanes (DL). Where the classification has already been made by Martini
et al. (2003), we indicate this with "-mp."
.
3.40. NGC 7331 (DL)
Figure 19 (bottom).
Images: Smooth in both NICMOS and STIS images, with a dust lane along
the western edge of the color map.

10. 2002ApJS..142..223F
Re:NGC 7331
NGC 7331. NVSS data imply strong resolution effects for the ~2 north-south
extended radio emission associated with NGC 7331. The Green Bank survey
measured an 80 mJy source. 1.49 GHz, 54" resolution map of Condon
(1987), shows a north-south, 373 mJy source. 1.5" resolution, 1.4 and 5
GHz maps were obtained by Cowan, Romanishin, & Branch (1994). The maps
show a central unresolved flat spectrum radio source of 0.23 and 0.12
mJy, respectively, and a ring of radio emission around the central
source, containing mainly nonthermal sources which may be supernova
remnants.
Similar to the high-resolution image of NGC 660, we detect a ring of
radio emission, cospatial with the galaxy major axis. Due to the
complexity of the source and the reduced sensitivity relative to the
observations of Cowan et al. (1994), we were not able to detect the
radio core. As judged from tapered maps (~7" resolution), the total 8.4
GHz flux density is approximately 50 mJy.
We also detect a strong source (NGC 7331SW), 4' away from the target
center, to the southwest. Since this source is almost at the primary
beam edge, our estimate of 20 mJy should be taken as a lower limit. NED
shows that the closest source, 6" away, is the 423 mJy radio source
TXS 2234+340 (Douglas et al. 1996). There is no NVSS detection, and
APM data for this field are as yet lacking.

11. 2002AJ....124..675C
Re:UGC 12113
Both NVSS components comprise this very extended source.

12. 2002A&A...389...68G
Re:NGC 7331
NGC 7331: the results of our two methods agree very well
between them, and with the main kinematic estimates. We thus
adopt the average of our two methods.

13. 2002A&A...388...50F
Re:NGC 7331
The presence of a SMBH (M_black hole_ ~ 10^8^M_sun_ ) in the center
of NGC 7331 has been debated by different authors (Afanasiev et al.
1989; Bower et al. 1993; Mediavilla et al. 1997; Sil'Chenko 1999).
The debate centers on observations of the distribution and
kinematics of ionized gas. Our PV diagram is similar to that of
NGC 772. We measure an increase of the integrated flux of the
[O III]{lambda}5007 line at smaller radii, along with constant
velocity gradient and to slight increase of the velocity
dispersion. The PV diagram of NGC 7331 is of Type III.

14. 2001ApJS..137..139S
Re:NGC 7331
NGC 7331. - We adopt the Cepheid distance from Hughes et al. (1998).

15. 2001A&A...374..394V
Re:NGC 7331
NGC 7331: Our V_g_'s matches those by Bottema (1999). A difference in the
heliocentric systemic velocity and the different position angle of the slit
(PA = 170^deg^) may explain the shift the V_g_ curve by Afanas'ev et al.
(1989).

16. 2001A&A...374..394V
Re:NGC 7331
NGC 7331: The V_*_ gradient measured by Heraudeau & Simien (1998) is
shallower than that by us and other authors. We suggest it may be due to a
different position of the slit. Our {sigma}_*_ radial profile shows a
faster decrease and at larger radii it is marginally consistent with that
by Bower et al. (1993).
For some of the sample galaxies velocity fields for the cool gaseous
component have been obtained using CO molecular lines and/or H I 21-cm
line and can be compared to our ionized-gas velocity curves to have some
insights into the inner-to-outer gas distribution and motion.

17. 2001A&A...374..394V
Re:NGC 7331
NGC 7331: Sofue (1997) obtained a rotation curve for the gaseous component
from CO and H I lines. The global rotation appears normal with no peculiar
behaviour. There is no gas component associated to the counter-rotating
bulge claimed by Prada et al. (1996).

18. 2000ApJS..128..431F
Re:NGC 7331
A7. THE NGC 7331 GROUP
NGC 7331 and NGC 7457 are about 7^deg^ from each other, and have
the same heliocentric velocity. T88 assigns the two galaxies to the same
cloud but different groups. We classify their physical association as
probable.

19. 1999A&AS..138..253B
Re:NGC 7331
NGC 7331 - SN 1959D: patch 1 is within a 3{sigma} detection limit; patch
2 is brighter and blue, although appears compact on the image and might
be only a star. Patch 3 is also blue and compact. These patches are also
visible on the archival WFPC-2 image that we analyzed. With WFPC-2 it
is clear that there are groups of stars present (possibly new forming
stars) and/or HII regions belonging to a galaxy spiral arm.

20. 1998PASJ...50..427S
Re:NGC 7331
NGC 7331: The nuclear component is hardly visible in the H{alpha} line,
while it is evident in [N II], showing a rapidly rising rotation at
R < 2". The rotation of the nuclear disk is rather slow, ~ 100 km s^-1^.
The disk part is clearly traced in the H{alpha} line, reaching a maximum
at R ~ 35", beyond which the rotation is flat.

21. 1998A&A...335..807A
Re:NGC 7331
This is a highly inclined (i_~70^deg^; Corradi & Capaccioli 1991) Sb
galaxy with a prominent bulge which rotates retrograde with respect to
the disk (Prada et al. 1996). Within the central few arcminutes there is
a dearth of both atomic and molecular gas (von Linden et al. 1996). The
FIR emission is already known, from KAO observations, to be rather 'flat
topped' in this region (Smith & Harvey 1996). The 200 micron structure
resembles, to a large degree. the morphology evident in the 100 micron
image although the longer wavelength emission appears to be more
extensive. Bianchi et al (1998a) have recently mapped NGC 7331 at 450
microns and 850 microns using the submillimeter array SCUBA (effective
resolution of 10" and 15" respectively). They detect a bright submm ring
surrounding the nucleus at a radius of 2-3 kpc. This 'dust ring' appears
to be co-spatial with a concentration of molecular gas at the same
radius.

22. 1997AJ....114.2428S
Re:NGC 7331
NGC 7331: The PV diagram shows a rigid-body increase, corresponding to a
ring-like distribution of gas at a radius 30" (2 kpc) rotating at V_rot_=250 km
s^-1^. The rotation is then flat to +/-2' (8 kpc). The central 20" (1.4 kpc)
region shows weak CO emission. The averaged velocity profile shows a typical
double-horn property, characteristic to a rotation disk with a constant
velocity.

23. 1995A&A...302..691D
Re:NGC 7331
Although NGC 7331 is not a genuine edge-on galaxy with its inclination of
71^deg^ (Shostak 1978), we have included it in this sample because it
allows to study the geometrical effect of this inclination on the radio
emission. The emission is extended much further to the south than to the
north, a fact which has already been seen by Klein et al. (1984). The
extension to the south could be an indication for a possible interaction
between NGC 7331 and a member of Stephan's Quintet.
The polarized emission is visible as two maxima, located on either
side of the major axis and shifted slightly to the north on the western
side (the nearer one) and to the south on the eastern side. The existence
of two separate maxima may again be due to depolarization in the galactic
plane, but the shifting of these two maxima along the major axis is a
consequence of the moderate inclination of 71^deg^ (see Sect. 6). Hence,
the appearance of the polarized intensity is again consistent with a
large-scale field parallel to the plane.

24. 1994CAG1..B...0000S
Re:NGC 7331
Stephan's quintet
Hubble Atlas, p. 17
Sb(rs)I-II
PH-64-H
Oct 13/14, 1950
103aO
30 min
NGC 7331 has a spiral pattern of the MAS
type, similar to that of M31. However, the
nuclear bulge is smaller than in M31, and the
arms in NGC 7331 can be traced closer to the
center than in M31.
NGC 7331 is superposed on a more-distant
group of early-type galaxies with a mean redshift
of about 6000 km/s, of which Stephan's quintet
is a subgroup. Three galaxies of this more-distant
group can be seen in the print here.
As described in the Hubble Atlas, NGC 7331
played a crucial role in settling an early
problem as to the direction of the opening of the
spiral pattern relative to the direction of rotation
of the galaxy.

25. 1993A&AS...97..887B
Re:NGC 7331
NGC 7331 is a ringed galaxy studied by Young & Scoville (1982). Our (0,0)
coordinates are slightly southwest of the central CO hole and real center
of the galaxy (see Figure 2).

26. 1976RC2...C...0000d
Re:NGC 7331
= Holm 795a
Brightest in a group and in foreground of a group of faint galaxies.
Photograph:
Ap. J., 141, 758, 1965.
Ap. J. (Letters), 178, L101, 1972.
P.A.S.P., 78, 495, 1966.
Astr. Ap., 29, 249, 1973.
Stellar Structure, Vol. VIII of Stars and Stellar Systems, 395, 1965.
IAU Symp. No.44, p.388, 1972.
Photometry (5 Color):
A.J., 73, 313, 1968.
Photometry (UBV):
Ap. J., 157, 55, 1969.
Spectrum:
Ap. J., 141, 759, 1965.
Velocity of background galaxy:
IAU Symp. No. 44, p.376, 1972.
Spectrophotometry:
Astr. Ap., 27, 433, 1973.
Sov. A.J., 16, 628, 1973.
Polarization:
Astrofizika, 4, 409, 1968.
Ap. J. (Letters), 170, L53, 1971.
Dynamics, Rotation Curve and Mass Determination:
Ap. J., 141, 759, 1965.
Ap. J., 184, 735, 1973.
Vest. Leningrad No. 1, 140, 1969.
Astr. Ap., 8, 364, 1970.
HII Regions:
Ap. J., 183, 411, 1973.
SN1959D
Stellar Structure, Vol. VIII of Stars and Stellar Systems, 395, 1965.
M.N.R.A.S., 158, 375, 1972.
Ap. J., 182, 225, 1973.
"Supernovae & SN Remnants", Ap. & Space Sc. Lib., 45, p.91, 1974.
HI 21cm and Distance Modulus:
Astr. Ap., 25, 319, 1973.
Astr. Ap., 35, 441, 1974.
Halo Search:
Astr. Ap., 28, 95, 1973. (not detected).
Radio Observations:
Ap. J., 144, 553, 1966.
Ap. J., 150, 413, 1967.
Ap. J. (Letters), 174, L111, 1972.
Ap. J. (Letters), 182, L17, 1973.
Astr. Ap., 29, 249, 1973.
Astr. Ap., 31, 447, 1974.
Astr. Ap., 33, 343, 1974.
M.N.R.A.S., 166, 11P, 1974.

27. 1973UGC...C...0000N
Re:UGC 12113
SA(s)bc (de Vaucouleurs), Sb+ (Holmberg)
SN? 1899 (probably non-existing; emulsion defect?)
SN 1959d
See UGC 12101
Quadruple group preceding, include UGC 12116 = NGC 7335, UGC 12120 = NGC 7337,
and NGC 7340 (see UGC 12116)

28. 1964RC1...C...0000d
Re:NGC 7331
= Holm 795a
Brightest in a group of faint objects.
NGC 7333 = Holm 795i is a star (misidentified in Lick 13). NGC 7338 = Holm 795d
is a star as are NGC 7325 = Holm 795f, NGC 7327 = Holm 795g, and NGC 7326 =
Holm 795h.
Lund 6 dimensions are for the bright part only.
Photograph:
Ap. J., 97, 114, 1943.
Ap. J., 133, 892, 1961.
Photometry:
Stokholm Ann., 13, No.8, 1941.
Stokholm Ann., 14, No.3, 1942.
Ap. J., 104, 212, 1946.
Spectrum:
Ap. J., 135, 699, 1962.
Orientation and Rotation:
Ap. J., 97, 117, 1943.
Ap. J., 127, 487, 1958.
Polarization:
Stockholm Ann., 19, No.1, 1956.
HII Regions,
Zeit. fur Ap., 50, 168, 1960.
SN 1959
HAC, 1438, 1959.
P.A.S.P., 72, 127, 1960.
P.A.S.P., 72, 208, 1960.
Ap. J., 133, 869, 1961.

29. 1961Hubbl.B...0000S
Re:NGC 7331
Sb
PH-64-H
Oct. 13/14, 1950
103 O
30 min
Enlarged 5.1X
This galaxy, seen almost on edge, is of the NGC 2841, NGC 5055
type, though the spiral arms do not seem to be as thin
and are more easily visible. The increased visibility of
the arms may be an effect of projection, because the dust
lanes and interspersed luminous arms are silhouetted
against the bright background luminosity of the central
regions of the galaxy. Spiral arms can be seen to within
about 12 sec of arc (radius) of the center (about 6 mm on
the scale of the illustration). This illustration does not
show the detail in the central regions. The burned-out
central region is not amorphous like the center of M31
or M81 but has a spiral structure like that in NGC 5055.
NGC 7331 is one of the galaxies often used in discussions
of the direction of rotation of spiral arms. There is
no question about which way the arms open in NGC 7331; the
debatable point is which is the near and which the far side
of the galaxy. The Lindblad School believes that the east
side is the near one, in which event the arms would be
leading because spectroscopic data show that the north
end of the spindle is approaching. The original plate,
PH-64-H, from which this illustration was made, appears
to settle the argument. A part of the light from the nuclear
bulge can be seen beneath the dust line on the west
side. The nuclear light can just be seen on this positive
reproduction. But a negative print from PH-64-H is
given by de Vaucouleurs in Ap. J., 127, 487, 1958 (Fig. 5)
which shows this particularly well. If the identification
of the light with the nuclear bulge is correct, the west is
the near side and the spiral arms are trailing.

30. 1918PLicO..13....9C
Re:NGC 7331
Vol. VIII, Plate 67. A fine bright spiral 9.5' x 2' in p.a. 165^deg^. Very
bright, elongated nuclear portion, within which is a bright, hazy nucleus. The
whorls show a number of condensations, not very sharp. See Abs. Eff. 27 s.n.


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