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Notes for object NGC 0925

15 note(s) found in NED.


1. 2009A&A...503..409H
Re:NGC 0925
There is no polarized emission detected in this galaxy. However, several faint
background sources are seen toward the edges of the field. Excluding the
unresolved polarized source most discrepant from the single double source lobe,
we obtain an estimate of the Galactic foreground RM with a value of about
-10+/-2 rad m^-2^.

2. 2008MNRAS.390..466E
Re:UGC 01913
UGC 1913. The kinematical centre chosen in Paper IV is different from the
morphological centre chosen here, leading to a different rotation curve.

3. 2008AJ....136.2648D
Re:NGC 0925
4.1 - NGC 925 is classified as a late-type barred spiral. It was previously
observed in H I by Pisano et al. (1998). Figure 6 compares the rotation curves.
The main difference with our analysis, namely the position of the dynamical
center, is discussed in Trachternach et al. (2008). This difference also
explains the slightly higher value for V_sys_ of 551.5 km s^-1^ found by Pisano
et al. (1998), compared with our 546.3 km s^-1^. Other than this, we derive
broadly similar trends of i and P.A. with radius. The curves themselves agree
within the uncertainties, showing that for solid-body (inner) rotation curves,
such as this one, the shape does not critically depend on the position of the
center. The uncertainties quoted in Pisano et al. (1998) are the formal fit
errors. As discussed before, these are unrealistically small, representing the
error in the mean velocity along a ring, rather than the scatter. In this case
these formal errors are smaller than the sizes of the symbols in Figure 6. The
uncertainties we have adopted are more representative of the true physical
uncertainties.

4. 2008AJ....136.2648D
Re:NGC 0925
6.1. NGC 925 - The surface brightness profiles of NGC 925 are shown in Figure
22. The 2MASS J, H, and K profiles can be traced out to ~250"; the 3.6 {mu}m
profile can be traced over the entire extent of the H I disk. NGC 925 shows no
evidence for a bright central component. There is also no evidence for a strong
color gradient, and we assume a constant {GAMMA}^3.6^_*_ = 0.65 for the disk.
The rotation curves are shown in Figure 23. The predicted {GAMMA}^3.6^_*_ value
make NGC 925 slightly exceed maximum disk. The ISO model can to some degree
accommodate this, but the NFW model can do so to a lesser extent. This does not
change when adopting the Kroupa{GAMMA}^3.6^_*_ values. Fits with {GAMMA}^3.6^_*_
free prefer lower values for {GAMMA}^3.6^_*_. For the NFW case a negative
{GAMMA}^3.6^_*_ is preferred; we have assumed a fixed {GAMMA}^3.6^_*_ = 0 in
this case. For both fixed and free {GAMMA}^3.6^_*_ the NFW model yields
parameters that are inconsistent with the CDM expectations (see Section 5.3.1),
resulting in V_200_ values many times larger than the maximum rotation of the
galaxy and c values approaching zero. This is a general symptom of an NFW halo
trying to fit a linearly rising rotation curve (McGaugh & de Blok 1998). The ISO
models in general fit the data better than the NFW models.

5. 2006MNRAS.366.1265B
Re:NGC 0925
This late-type SBcd galaxy has a bright optical and H{alpha} bar and two bright
patchy spiral arms beginning at the ends of the bar. Many H II regions lie along
the bar. The photometrical and kinematical data agree. The PV diagram shows
non-axisymmetric motions near the centre. It is well studied in H I (Elmegreen,
Wilcots & Pisano 1998; Pisano, Wilcots & Elmegreen 1998), in CO (Helfer et al.
2003) and in H{alpha} (Marcelin, Boulesteix & Courtes 1982). It shows strong
streaming motions.

6. 2005MNRAS.360.1201H
Re:NGC 0925
NGC 0925. This late-type SBcd galaxy has a bright optical and H{alpha} bar and
two bright patchy spiral arms beginning at the ends of the bar. Many H ii
regions lie along the bar. Photometrical and kinematical data agree. The PV
diagram shows non-axisymmetric motions near the centre. It is well studied in H
i (Elmegreen, Wilcots & Pisano 1998; Pisano et al. 1998), in CO (Helfer et al.
2003) and in H{alpha} (Marcelin, Boulesteix & Courtes 1982). It shows strong
streaming motions.

7. 2005A&A...437..837D
Re:NGC 0925
Figures 7 and 8 show both the observational data for H II regions in the barred
spiral galaxy NGC 925 and our result models plotted against the galactocentric
distance R. An angular scale of 1 " = 34.3 pc (Martin & Roy 1994) was assumed.
Figure 9 shows the O/H abundance gradient found by us, the O/H estimates
obtained by Martin & Roy (1994) using the O/H indicator [O III]/H{beta}, the
ones by van Zee et al. (1998) obtained both from direct abundance determinations
for two H II regions only and from a comparison with a grid of photoionization
models by McGaugh (1991) for other objects, and finally the O/H gradient derived
by Pilyugin et al. (2004) via the P-method for R < 5.6 kpc. Our oxygen gradient,
represented by 12+log (O/H) = (-0.016 +/-0.003) R (kpc) + (8.76 +/- 0.02),
yields O/H values higher by 0.2 dex than the ones derived by Martin & Roy (1994)
and van Zee et al. (1998) and higher by 0.2 to 0.5 dex than the ones via
P-method. As can be seen in Fig. 8, the flattening in the R_23_ oxygen indicator
at R ~ 6.0 kpc could be indicating the presence of an oxygen break in NGC 925.
However, the H II regions beyond this limit have abundances lower than 12+log
(O/H)= 8.2 (Pilyugin et al. 2004), which can produce a false bend in the slope
of the oxygen gradient obtained from the O/H calibrations (Pilyugin 2003b).
Also in Fig. 9, the N/O and S/O gradients obtained from our models are
compared with those derived by van Zee et al. (1998) and by Pilyugin et al.
(2004) using the P-method. Our models yielded N/O values consistent with the
ones derived by Pilyugin et al. (2004), but they are somewhat larger than the
ones from van Zee et al. (1998). The N/O gradient derived from our models is
given by log (N/O) = (-0.029 +/- 0.003) R (kpc) - (1.10 +/- 0.04). As can be
seen in Fig. 7, the [N II]/[O II] line ratios are about constant at R > 5 kpc,
from which an artificial abundance break could be inferred if we used general
abundance calibrations as, for example, the [N II]/[O II] vs. O/H calibration by
Kewley & Dopita (2002).
We found a flattened S/O gradient of log (S/O) = (-0.007 +/- 0.003) R (kpc) -
(1.47+/-0.02), which yields S/O values consistent with the ones obtained by van
Zee et al. (1998); however, for the outermost H II region, the S/O value
obtained by van Zee et al. (1998) is lower than the one derived by us by about
0.4 dex. For this object the [S III]{lambda}6312 line was not detected, so van
Zee et al. (1998) used an average value for the ionization correction factor to
derive the sulfur abundance, which can make this value doubtful. A T_eff_
gradient represented by T_eff_(10^4^ K) = (0.027 +/- 0.006) R (kpc) + (3.97 +/-
0.03) and log U ranging from -2.4 to -3.0 were derived from our models.
Castellanos et al. (2002) observed four inner H II regions in NGC 925, in the
distance range of 0.17-1.4 kpc, namely CDT1, CDT2, CDT3, and CDT4. Using an
S_23_ vs. O/H calibration, S_23_ = ([S II] {lambda}{lambda}6716,6731+[S III]
{lambda}\{lambda}9069,9532)/H{beta}, they derived 12+log (O/H) = 8.52, 8.71,
8.50, and 8.41, respectively, for these regions. These values are lower than the
ones we derived by about 0.3 dex. However, Castellanos et al. (2002) noted that
their O/H determinations can be somewhat uncertain, because the measured values
of S_23_ fall near the reversal point of the abundance calibration relationship.
Using detailed photoionization models based on the NLTE atmosphere models of
Mihalas (1972), Castellanos et al. (2002) obtained for CDT1 and CDT4 mean values
of 12+log (O/H) = 8.7, log (N/O) = -0.97, log (S/O) = -1.71, and T_eff_ = 36 500
K. The T_eff_ and N/O values are about the same as in our results, while the S/O
ratio is lower than our predictions by 0.25 dex.

8. 2002ApJS..140..303L
Re:NGC 0925
NGC 925 (Fig. 40).-NGC 925 is a particularly important test case since
{beta} = -2.6 suggests a totally unreddened population. Therefore, any
disagreement between the theoretical and observed flux at the shortest
wavelengths would immediately reveal model deficiencies and could not
be blamed on reddening. Despite being low S/N, the spectrum is adequate
for this test. The line profiles indicate an age of tens of Myr, and
the theoretical continuum agrees with the observations over the entire
wavelength range.

9. 2002AJ....124..675C
Re:UGC 01913
Diffuse radio source; the NVSS flux density may be too low.

10. 1994CAG1..B...0000S
Re:NGC 0925
Hubble Atlas, p. 37
SBc(s)II-III
PH-71-S
Dec 26/27, 1951
103aO + WG2
15 min
NGC 925 is one of the gems in the sky. It is
highly resolved into individual stars starting at
about B = 20. Numerous HII-region complexes
exist, the largest of which have angular diameters
of about 5".
Stellar associations can be identified in the
arms. The bar is full of HII regions and resolved
stars. NGC 925 is one of the premier galaxies not
far beyond the Local Group where studies of the
stellar content will be important for the
distance-scale problem. Cepheids should be easy to
detect if the photometry can be pushed to B = 26.
The redshift of NGC 925 is v_o = 792 km/s.

11. 1993A&AS...97..887B
Re:NGC 0925
NGC 925 is a strongly barred somewhat distorted system. According to the
Hubble Atlas (Sandage 1961), NGC 925 is in the same group as NGC 891 and
IC 239 (among others). Many HII regions are visible and this is one of
the galaxies where spiral structure is best traced by them (Garcia-Gomez
and Athanassoula, 1991). The northern and southern arms appear different,
the southern arm being better defined by the HII regions and containing
more of them. The CO flux is below average for the FIR flux but clearly
detected, especially in CO(2-1). The integrated FIR flux is about 2.5
times the central FIR flux and the cuts along the IRAS scanning direction
show extended emission, despite the non-alignment with the optical
emission (Rice et al. 1988). It is possible that there are CO maxima
elsewhere, perhaps in the south-to-western arm which contains many HII
regions. Given the size of the region we observed and the overall size of
the galaxy any H_2_ mass estimate would be useless. The important thing
is that in a galaxy with obvious star formation, especially in the
nucleus, only a small amount of molecular gas was observed.

12. 1976RC2...C...0000d
Re:NGC 0925
In the NGC 1023 Group.
Note corrected Dec.
Description:
P.A.S.P., 79, 152, 1967.
Photograph:
Ap. J., 140, 85, 1964.
Izv. Crimea Obs., 45, 162, 1972.
Photometry: (7 Color)
Izv. Crimea Obs., 45, 162, 1972.
IAU Symp. No. 44, 162, 1972.
Dynamics, Rotation Curve and Mass Determination:
Ap. J., 140, 85, 1964.
Astr. Ap., 8, 364, 1970.
HII Regions:
"Atlas and Catalogue", Univ. of Washington, Seattle, 1966.
Ap. J., 155, 417, 1969.
Ap. J., 194, 559, 1974.
Distance Modulus:
Ap. J., 194, 559, 1974.
HI 21cm:
Ap. J., 142, 1366, 1965.
Ap. J., 150, 8, 1967.

13. 1973UGC...C...0000N
Re:UGC 01913
SAB(s)d (de Vaucouleurs), Sc+ (Holmberg)
Note position error in RC1

14. 1964RC1...C...0000d
Re:NGC 0925
In the NGC 1023 Group.
No bright nucleus(?).
Well resolved.
Two (2) main, knotty, filamentary arms with branching
Dark material in central part.
Short pseudo bar.
Several dwarf Im galaxies nearby.
Minor diameter in Heid. 9 rejected.
(B-V) constant, interpolated value.
Photograph and Spectrum:
IAU Symp. No. 5, 1958 = Lick Cont. II, 81, 1958.
HII Regions:
Zeit. fur Ap., 50, 168, 1960.

15. 1961Hubbl.B...0000S
Re:NGC 0925
Sc/SBc
PH-71-S
Dec. 26/27, 1951
103aO + WG2
15 min
Enlarged 2.5X
The four galaxies shown on the facing page are very late
Sc. Some authors, including Shapley, have called galaxies
of this type Sd. All four systems have rather low surface
brightness, have spiral arms which are sometimes difficult
to trace, and are highly resolved into stars and HII regions.
NGC 0925 is a member of a group of galaxies with
NGC 1023, NGC 0891, NGC 1058, NGC 1003, and IC 0239 as members.
The mean redshift of this group is about 500 km/sec.
The distance modulus corresponding to this redshift is
(m-M) = 29.0. There are many HII regions in the arms
of NGC 0925, the largest of which has an angular diameter of
about 5 sec of arc, corresponding to 170 parsecs at the
assumed distance.


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