Date and Time of the Query: 2019-08-26 T00:14:20 PDT
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Notes for object NGC 4639

18 note(s) found in NED.

1. 2006MNRAS.366..812C
Re:NGC 4639
This barred galaxy exhibits a remarkable inner ring (Evans et al. 1996; Gonzalez
et al. 1997). The outer gaseous distribution is furthermore reminiscent of an
outer pseudo-ring. This outer structure is visible in the B-band image but
hardly in the NIR image, which principally shows the bar and the bulge. The
velocity field is rather regular, consistent with a flat circular velocity
pattern of the disc. It also shows streaming motions in the ring. A steep
velocity rise is seen in the galaxy core, as was also observed in Rubin et al.

2. 2002ApJS..139....1T
Re:NGC 4639
NGC 4639 (S1.0).-A detailed analysis of the ASCA data is presented in
Ho et al. (1999). The reanalysis of the same data set in this paper
shows a hint of an Fe K line. The ROSAT HRI image shows a pointlike
nucleus (Koratkar et al. 1995). A Chandra image in the hard band is
dominated by the nucleus.

3. 2002A&A...392..817F
Re:NGC 4639
3.9 NGC 4639
We find two ULX, but one of them (ULX2) was detected with the MOS, but not
with the PN, because its position fell into a gap between the PN chips. In
both cases, the statistics were not sufficient to perform spectral fitting.

4. 2002A&A...389...68G
Re:NGC 4639
NGC 4639: there is good agreement between the values obtained by
our methods. Thus, we take the average values. This is also in
agreement with the literature values.

5. 2001ApJS..136...61S
Re:NGC 4639
5.22. NGC 4639
This galaxy contains many H II regions which lie both at the ends of a
stellar bar and in a ring 30" from the nucleus (Gonzalez-Delgado et al.
1997). The AGN itself appears to contribute very little (3%) to the total
ionizing luminosity (Gonzalez-Delgado et al. 1997). Owing to their
detection of broad hydrogen emission lines (FWHM = 3600 km s^-1^ for
H{alpha}), Ho et al. (1997a) classified this galaxy as Seyfert 1 (although
low-luminosity). Further, they report an H{alpha} flux variation of 10%
between two observations a year apart, though caution should be used in
interpreting this due to the sensitivity of the result on detailed stellar
light removal. The Seyfert nucleus, which is pointlike in the ROSAT soft
X-ray band, has a low X-ray luminosity, but its X-ray spectral properties
are very similar to more powerful Seyfert nuclei (Koratkar et al. 1995).
Ho et al. (1999), compared ASCA data with archival Einstein and ROSAT data
and find variations on scales of months to years, with some suggestion of
variability on timescales of ~10^4^ s from the ASCA data alone.

6. 2001ApJS..133...77H
Re:NGC 4639
NGC 4639 (S1.0). - This galaxy was marginally detected at 6 cm but not
at 20 cm. Hummel et al. (1985) obtained a less stringent upper limit of
S_20_ < 1 mJy ({DELTA}{theta} = 1.5").

7. 2001AJ....122..637H
Re:NGC 4639
NGC 4639. - Koratkar et al. (1995) fitted the spectrum with an absorbed
power law of photon index 2.27. The resulting unabsorbed 0.2-2.2 keV flux
is somewhat higher than ours, but it has been corrected for a best-fit
column density that exceeds the Galactic N_H_. If we use the same column
density in our model, we obtain a similar flux.

8. 1999AJ....118.2331V
Re:NGC 4639
Images in F218W, F300W, F439W, and F547M of NGC 4639 are available.
Unfortunately, the deeper and more numerous Sandage et al. Cepheid
project images of this galaxy (Saha et al. 1997) do not contain the SN
site, because of the site's proximity to a very bright foreground star.
However, from the images we obtained, using the absolute SN position
from the Sternberg SN catalog, we find that the SN occurred near the
edge of the galaxy along an outer spiral arm. The images in each band
are not deep enough to resolve any individual bright stars or clusters
within the 1.5" radius error circle nor for us to measure the colors of
the environment.

9. 1997ApJS..112..391H
Re:NGC 4639
NGC 4639.--This rather prominent Seyfert 1 galaxy had gone unnoticed prior to
our survey (Filippenko & Sargent 1986). To better characterize the broad
H{alpha} component, we removed the narrow-line contribution using a [S II]
model (Fig. 6f). The final broad profile (observed on 1985 February 24 UT) has
FWHM~3600 km s^-1^ and FWZI~9600 km s^-1^; a separate spectrum obtained about a
year later showed flux variability at the level of ~10%. A broad component is
seen in H{beta} and possibly also in H{gamma}.

10. 1997ApJS..108..155G
Re:NGC 4639
This is a S1 nucleus in an SBb galaxy. The nuclear emission is compact,
and the disk shows H II regions that contribute to 97% of the total
emission. Thirty-four regions have been detected, and many of them are
located in a ring at 30" (~2 kpc) from the nucleus, clumped at the
ends of the stellar bar.

11. 1997A&A...319...33A
Re:NGC 4639
NGC 4639 This is the shortest exposure Seyfert field considered here (6.6ks).
The Seyfert is weak (C=21.6) and there is only one other source registered in
the field with C>5. There are a group of 8-9 sources, 1 4639 for which identifications have not been attempted here.

12. 1996ApJS..105...93E
Re:NGC 4639
4.9. NGC 4639
Pogge (1989) has obtained both narrow-band H{alpha} + [N II]
{lambda}{lambda}6548,6583 and [O III] {lambda}5007 CCD images of this object.
Measurements of the total UV continuum flux from the galaxy at 1650 A and
2000 A are published by Deharveng et al. (1994) and Donas et al. (1987),
respectively. Inspection of Figure 1 reveals numerous giant extragalactic H II
regions visibly distributed along the spiral arms. The concentration and
surface brightness of the H II regions appears to be largest in the spiral arms
near the ends of the bar, although none are visible along the bar itself. Star
formation may be enhanced in the regions of the arms near the ends of the bar
through mechanical interactions in the local ISM.

13. 1995ApJS...98..477H
Re:NGC 4639
Filippenko & Sargent (1986) reported the discovery of this low-luminosity
Seyfert 1 galaxy. With a broad H{alpha} luminosity of 6 x 10^39^ ergs
s^-1^, NGC 4639 is four times fainter than NGC 4051. Koratkar et al.
(1995) discuss the X-ray properties based on ROSAT observations. The
soft X-ray spectral slope, luminosity, and morphology of NGC 4639 are
similar to those of more luminous Seyferts.

14. 1994CAG1..B...0000S
Re:NGC 4639
VCC 1943
Feb 26/27, 1979
103aO + Wr2c
45 min
NGC 4639, a member of the Virgo Cluster,
has a redshift of v_o = 860 km/s. Many of its HII
regions are concentrated in the spiral arms,
where they begin at the ends of the bar. The
largest of these regions resolves into disks at the
3" diameter level.

15. 1976RC2...C...0000d
Re:NGC 4639
Photometry and Isodensitometry:
Ap. J. Suppl., 26, No. 230, 1973.
Observatory, 88, 239, 1968.

16. 1973UGC...C...0000N
Re:UGC 07884
Sb+ (Holmberg)
Companion 2.9, 280, 0.7 x 0.3
Paired with UGC 07902 at 17.5

17. 1964RC1...C...0000d
Re:NGC 4639
Lick 13 and Uppsala 21 dimensions are for the bright part only.

18. 1918PLicO..13....9C
Re:NGC 4639
Nearly round, 1' in diameter; moderately bright, almost stellar nucleus; the
whorls form a faint ring.

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