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Date and Time of the Query: 2019-06-19 T10:39:47 PDT
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Notes for object IC 3576

5 note(s) found in NED.


1. 1988A&AS...75..273D
Re:IC 3576
(= MCG 1-32-112 = UGC 7781 = DDO 138) is a peculiar dwarf galaxy
classified as Sm by de Vaucouleurs et al. (1976) and Altschuler et al.
(1984). It belongs to the Virgo cluster, is rich in neutral hydrogen
(Margon et al., 1972; Fisher and Tully, 1975; Richter and Huchtmeier,
1984) and is not a continuum radio source (Erickson et al., 1978 ;
Altschuler et al., 1984). It has been identified to the X-ray source
4U 1232+07 (Margon et al., 1972; Bhavsar and Ulmer, 1979). However,
IC 3576 has not been detected by the IPC on the Einstein satellite
(Bergeron, unpublished). The two only X-ray sources found in the IPC
field during a 1800 s exposure are at the following positions:
1) {alpha} = 12h33mn11.3s, {delta} = +6d56'16", extent estimate:
insufficient counts; 2) {alpha} = 12h34mn19.2s, {delta} = +6d53'44",
extent estimate: point source.
They are respectively located 13.7' and 3.4' away from IC 3576
({alpha} = 12h34mn05.4s, {delta} = +6d53'47"), and we note that there
is a double star on the Palomar Sky Survey plate within a few
arcseconds of position 2. The identification of IC 3576 is therefore
not clear. No source was detected in an HRI exposure of 12400 s close
to the position of IC 3576 (Ulmer, private communication).
We find a redshift of z= 0.00380 +/- 0.00006 (averaged on the main
emission lines), corresponding to a galactocentric velocity of 1029
km s^-1^, and to a distance of 20.6 Mpc (with H_0_ = 50 km s^-1^
Mpc^-1^ used throughout). The optical spectrum of IC 3576 is shown in
figure 1 and emission line intensities are given in table III.
Contrary to all the other galaxies in our sample, IC 3576 does not
clearly show a nucleus on our long slit spectrum, but rather appears
very diffuse. Ionized gas is detected over 22.2" (2.2 kpc) along
PA = 200^deg^, coinciding with the brightest bar-like region clearly
appearing on the Palomar Sky Survey plate. These properties are
remindful of the galaxy MCG-05-3-052, observed by Meaburn (1983),
which has a diffuse HII region of 3.2 x 2.2 kpc^2^. Since no strong
gradients are observed in the line intensity ratios throughout
IC 3576, we only give results integrated over the whole emission line
region.

2. 1988A&AS...75..273D
Re:IC 3576
The H{alpha}/H{beta} line ratio is observed to be roughly equal to
its radiative value in the Case B recombination case (Brocklehurst,
1971). Therefore, we have applied no reddening correction before
deriving the physical parameters in this galaxy.
As seen from figure 1 and table III, the spectrum of IC 3576
resembles that of an HII region and does not suggest the presence of
an active nucleus (no detection of lines of very high excitation, such
as [NeV] 3426 and HeII 4686, or of very low excitation, as [OI] 6300).
Its continuum is rather blue, though notably less than that of giant
extragalactic HII regions, such as Tol 89 (Durret et al., 1985) the
continuum flux ratio F(3600)/F(6500) in IC 3576 is only about one
fourth that observed in Tol 89, implying that the number of hot stars
in IC 3576 is notably smaller than in Tol 89.
Since the [OIII] 4363 line is not measurable, we have estimated the
electronic temperature T_e_ from the ([OII] + [OIII])/H{beta} line
ratio (Pagel et al., 1979), as in all following non-Seyfert objects.
We have chosen this method to derive T_e_ rather than using the
[OIII]/[NII] line ratio (Alloin et al., 1979) because [NII] 6584 being
blended with H{alpha} its intensity is fairly uncertain. However, we
have checked that the results obtained with both methods are
comparable. The electronic density n_e_ has been derived from the
[SII] 6717/673l line ratio (see Tab. III).
The average density of the ionized gas, derived from the total
[OII] 3727 emission along the slit, is also given in table III, under
the form (l/1 kpc)^1/2^, where l is the depth of the ionized
region along the line of sight. The same value is found using the
[OIII] 5007 line instead of [OII] 3727. Therefore, as already noted
for other ionized nebulosities (e.g. Durret and Bergeron, 1986), the
average density is small, and the filling factor is notably less than
unity, implying that the ionized gas is clumpy. This is true for all
the other objects in our sample as well.
IC 3576 shows no velocity gradient throughout the nebulosity along
PA = 200^deg^: {delta}v < 50 km s^-1^.

3. 1976RC2...C...0000d
Re:IC 3576
= DDO 138
Description:
Photograph:
Ap. J. (Letters), 178, L77, 1972.
HI 21cm:
Ap. J. (Letters), 178, L77, 1972.
Astr. Ap., 34, 43, 1974.
Radio and X-rays:
Ap. J. (Letters), 178, L77, 1972.
Bull. A.A.S., 4, 413, 1972.

4. 1973UGC...C...0000N
Re:UGC 07781
DDO 138
S IV-V or S V (DDO)

5. 1966AJ.....71..922v
Re:DDO 138
= IC 3576


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