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Notes for object NGC 3125

10 note(s) found in NED.


1. 2000A&AS..145...71K
Re:NGC 3125
NGC 3125 = AM 1004-294: High intensity emission lines, low continuum.
This is a bright, compact low-redshift galaxy in a cluster with regular
outer isophotes and double knots, it is classified as an amorphous H II
galaxy (Telles et al. 1997) or a blue compact dwarf (Marlowe et al.
1997).

2. 1999A&AS..138..213D
Re:NGC 3125
Tololo 1004-296 (Tololo 3, NGC 3125; North up, East left): for this
BCDG, we obtain a total B magnitude of 14.2 which is 0.7 magnitude
fainter than Bergvall & Olofsson (1986) value, quoted in RC3, and 0.1
brighter than Kunth et al. (1988)'s value. The presence of 3
superimposed Galactic stars falling within the aperture used by Bergvall
& Olofsson could explain the measurement discrepancies.
The overall shape is roughly elliptical with an elongated bright
central region of asymmetric brightness distribution. An elongated
bright knot pointing North-East of the central "nucleus" leads to a
morphology similar to that of Fairall 301. The bluest knot in the star
forming region has a B-R color of 1.1, suggesting the presence of an
evolved stellar population. The surface brightness distribution is
consistent with a dominant r^1/4^ law, in agreement with another
photometric observation of this galaxy (Kunth et al.1988).

3. 1999A&AS..136...35S
Re:NGC 3125
NGC 3125 -- Broad He II {lambda}4686 emission was found by Kunth &
Sargent (1981; cf. also Kunth & Joubert 1985) in this dwarf galaxy.
They also note narrow [Fe III] {lambda}4658 emission. Broad
He II {lambda}4686 was detected in two regions by Masegosa et al.
(1991) and Vacca & Conti (1992). Pindao (1998) reconfirms the detections
of Masegosa et al.. The high S/N observations of Schaerer et al. (1999)
reveal broad features of N III {lambda}4640, He II {lambda}4686, and
CIV {lambda}5808 in both regions, testifying of the presence of late WN
and early WC stars.

4. 1999A&A...341..399S
Re:NGC 3125
In NGC 3049 and NGC 3125, the W-R regions coincide with the peaks of
the continuum emission and nebular lines distributions. NGC 3049 is a
barred spiral galaxy belonging to the Virgo cluster. This low-mass
galaxy has a small bulge and a thin bar of constant surface brightness
surrounded by an inner ring (Contini et al., 1997). The optical
appearance of NGC 3125 is an amorphous elliptical shape with a bright
central starburst region dominated by two bright knots (regions A and B)
apparently connected by a bridge of fainter intensity.

5. 1999A&A...341..399S
Re:NGC 3125
Penston et al. (1977) detected the He II {lambda}4686 emission line in
the North-West knot (= our region A) of NGC 3125, but do not mention W-R
stars. The W-R nature of NGC 3125 was first noted by Kunth & Sargent
(1981) who first envisioned their importance to elucidate the bursting
nature of star-formation processes in HII galaxies. They computed that
this starburst region contains several hundred W-R stars. Long-slit
observations of VC92 have first revealed W-R stars in the second
condensation 10" South-East of the nucleus (= our region B). In
region A of NGC 3125, the W-R bump around 4700 A is dominated by the
He II {lambda}4686 line whereas the N III {lambda}4640 +
C III {lambda}4650 blend and the He II {lambda}4686 line are of
similar strength in region B (see Fig. 7). We signal a marginal
(~1{sigma}) detection of broad He II {lambda}5412 emission, the
second strongest He II line in WN stars, in knot A. If confirmed
this represents, to our knowledge, the first detection of this line in
the integrated spectrum of an extra-galactic object. The spectrum of
region A also exhibits the typical high-excitation nebular emission
lines of [Ar IV ] {lambda}4711 and [Ar IV ] {lambda}4740 (see Fig. 7).
Their presence might imply a nebular contribution to the
He II {lambda}4686 line.

6. 1999A&A...341..399S
Re:NGC 3125
Only some of the observed W-R line intensities and equivalent widths
lie well on the predicted model curves plotted in Figs. 10 and 11.
NGC 5253 represents the best case (Schaerer et al., 1997). For the
considered objects we dispose in total of 15 measurements of broad
emission lines (all lines and all regions). The relative line intensity
of 7 data points is above the maximum value predicted by the standard
model. On the other hand the majority (12 of 15) of the equivalent
widths are well in the range of the model predictions. The three
remaining cases are W(He II {lambda}4686) of NGC 3125-A and Tol 89,
which could well be overestimated due to nebular contamination and
contributions from other lines in the blended region, and an
exceptionally large C IV {lambda}5808 in Tol 89 (cf. below).
The uncertainties affecting the observed quantities have been discussed
above (Sect. 5.1). Only for Tol 89 we have direct evidence that effect
(i) (displacement gas-stars) is likely of importance (Sect. 3); this
does, however, not exclude that the line intensities in some other
objects are also affected. Even after reducing I(WR)/H{beta} by a
factor ~1.4 due to effect (ii), discrepancies in the line intensities
remain. The observed W-R equivalent widths are mostly within the
predicted range, although the observed values could be underestimated
due to effect (iii). We feel, however, that our measurements are only
weakly affected by the old stellar populations (see Sect. 5.1). Other
possibilities to explain the observations of some regions with large
W-R/H{beta} intensities and large W(WR) may e.g. be a flatter IMF. These
are discussed in Sect. 5.3.
Regarding the signatures essentially attributed to WC stars (i.e.
N III {lambda}4640 + C III {lambda}4650, C IV {lambda}5808) we note a
shift in (H{beta}) between the observed and predicted equivalent widths
(bottom panels of Fig. 11, and Fig. 12). The shift looks as if WC stars
appeared to early and/or did not remain alive long enough. Possible
explanations for this "chronometer-shift" are: effects (i), (b), (d), or
variations in the burst duration, IMF, etc. (see Sect. 5.3). The
uncertainties in the interpolation techniques determining the number of
WC stars ((b)) seem large enough to explain this effect.

7. 1994CAG1..B...0000S
Re:NGC 3125
Amorphous
CD-721-S
Feb 1/2, 1979
103aO + GG385
45 min
NGC 3125 has an outer envelope morphology
similar to those in NGC 625, NGC 1705, and
NGC 5253. The disk is of high surface brightness.
There is a hint of resolution into individual
objects (stars?) in the outer envelope. The most
telling feature suggesting the Amorphous
classification is the two very bright objects near
the center (seen in the insert), of magnitude B = 17.
The redshift is v_o = 827 km/s. At the
redshift distance of 16 Mpc (m - M = 31) the
absolute magnitudes of the knots are M_B_ = -14,
similar to the luminosities of the four super star
clusters in NGC 625, NGC 1705, and NGC 1569,
described on the preceding panels.
The spectrum of the disk of NGC 3125
shows extremely hard, high-excitation emission
lines including HeII at 4686 (Penston, Fosbury,
Ward, and Wilson 1977). The three amorphous
galaxies just mentioned also have high excitation
emission spectra.
The presence of the super star clusters, the
hard emission radiation, and the amorphous light
of the envelope are the reasons for assigning the
Amorphous classification.

8. 1993ApJS...86....5K
Re:NGC 3125
NGC 3125 (Tol 3), Irr Am, BCDG.
This metal-poor, irregular amorphous galaxy is a dwarf undergoing strong
star formation activity (Kunth & Sargent 1983; Gallagher & Hunter 1987;
Kunth, Maurogordato, & Vigroux 1988). Recognized as a W-R galaxy in the
optical, its population seems to be the result of periodic bursts of star
formation followed by periods of quiescence (Kunth & Sargent 1981). The
UV spectrum has a P Cygni profile of C IV {lambda}1550, consistent with
the picture of NGC 3125 as a W-R galaxy.

9. 1985SGC...C...0000C
Re:NGC 3125
Plate 1321
High surface brightness, spike to north-preceding, between 2 bright
star. SB(rs)c 5.5 south-following, hexagonal, knots.

10. 1982ESOU..C...0000L
Re:ESO 100419-2941.5
=ESO 435- G 41
bright
in cluster


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