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Notes for object NGC 3991

10 note(s) found in NED.


1. 2003ApJS..146....1W
Re:NGC 3991
NGC 3991.-The spectra in the LiF1A and LiF2B segments look somewhat
different, but especially the LiF2B segment is rather noisy. The
combined spectrum was still used.
The short-wavelength wing of the Ly{beta} absorption associated with
NGC 3991 extends to near the O VI {lambda}1031.926 line, but only
marginally distorts the continuum there. A major problem with this
sight line is that the Si II {lambda}1020.699 line associated with
NGC 3991 lies adjacent to the negative-velocity edge of the
O VI {lambda}1031.926 absorption. Fitting other intrinsic lines
(C II {lambda}1036.337, O I {lambda}1039.230, Ar I {lambda}1048.220,
Si II {lambda}989.873) shows that the feature centered at -108 km s^-1^
is Si II {lambda}1020.699 in NGC 3991. This feature was fitted and
removed before measuring the Galactic N(O VI).

2. 2000AJ....119...79C
Re:NGC 3991
Cataloged as a peculiar galaxy by Arp (1966), NGC 3991 has also
been classified as a Magellanic irregular (see Fig. 5). NGC 3991 has an
optical spectrum similar to that of an H II galaxy (Keel et al. 1985;
Kennicutt 1992). NGC 3991 also has low-metallicity H II regions (Arnault
et al. 1988), and from our images it does not appear to contain an
extended shell or an outer portion distinct from its inner starburst
area. However, it is generally believed that the starburst in this
galaxy was triggered by an interaction with the neighboring galaxies
NGC 3994 and NGC 3995 (Keel et al. 1985). A detailed optical and
spectroscopic study of NGC 3991 (Hecquet et al. 1995) found several
separate knots in NGC 3991, each with extreme star formation and a size
of around 300 pc. A comparison of the colors of these knots indicates
that star formation is concentrated within and occurring rapidly in
these clumps (Hecquet et al. 1995).
NGC 3991 also has a high radio and X-ray flux (Seaquist & Bell
1968; Fabbiano, Feigelson, & Zamorani 1982). The UV spectrum of this
galaxy contains features associated with recently formed stars such as
Ly{alpha} and He II emission (Kinney et al. 1993). Although detected by
IRAS, NGC 3991 is not classified as an IRAS bright galaxy (Soifer et al.
1989). Therefore, the morphology of NGC 3991 is probably not dominated
by dust. We verify this by finding that the UV morphology is similar to
that in the optical R band. However, the southern H II regions
associated with a relatively bright UV cluster are faint in H{alpha} as
compared with the northern star-forming clumps.

3. 1994CAG1..B...0000S
Re:NGC 3991
Karachentsev 311 [= NGC 3994 and NGC 3995, nearby]
PH-8054-S
Pec(tides)
Feb 4/5, 1981
Arp 313
103aO
12 min
Racine wedge
NGC 3995 is the brightest galaxy of a
multiple interacting group whose next-brightest
members are NGC 3994 (Sbc; it is the closest
galaxy to NGC 3995) and NGC 3991. The
morphology of NGC 3991 is dominated by a thin
tidal plume in which very bright HII-region
candidates are present. Karachentsev lists redshifts
of v_o(3394) = 3086 km/s and v_o(3395) = 3232 km/s.
The redshift listed for NGC 3991 by
Palumbo et al. (1983) is 3256 km/s. From
these three redshift values, the mean redshift
distance of the group is 64 Mpc (H = 50).
The angular separations of NGC 3994 and
NGC 3991 from NGC 3995 are 1.9' and 3.7',
respectively. The corresponding projected linear
separations are 35 kpc and 68 kpc.
The morphology of NGC 3994 (the fainter
of the close pair) is normal for a late-type Sbc or
Sc. There is no evidence of tidal distortion
despite its apparent closeness to NGC 3395.
However, tidal disruption is clearly evident in
NGC 3991, the more distant in projection of the
triplet.
The two main prints of NGC 3395 (the
brightest galaxy of the group) also show evidence
of morphological distortion. It would seem that
the interaction has been between NGC 3995 and
NGC 3991, not involving NGC 3994.

4. 1993ApJS...86....5K
Re:NGC 3991
NGC 3991 (Haro 5); Im, BCG.
This Magellanic irregular belongs to a multiple interacting system, which
also includes NGC 3994 and NGC 3995. The gravitational interaction with
the companions may trigger the activity of the galaxy (Keel et al. 1985).
The optical spectrum shows that NGC 3991 resembles an H II galaxy, with a
very blue nucleus (Keel et al. 1985). The BCG nature is supported by its
low metallicity (see, e.g., Arnault et al. 1988, where the problem of
nondetection of CO in BCGs is also treated) and by the characteristics of
our UV spectrum, which according to Rosa et al. (1984) resembles an H II
region. A higher level of activity is revealed in the radio, where the
emission is comparable to that of a Seyfert galaxy (Seaquist & Bell
1968), and in the X-ray (L_X_ = 2.5 X 10^41^ ergs s^-1^; Fabbiano et al.
1982). The authors attribute the X-ray emission to the intense
star-forming activity. This spectrum with high signal-to-noise ratio
shows absorption lines as well as emission in Ly{alpha} and He II.

5. 1985ApJS...57..643D
Re:VV 523
Elongated spiral (banana shape).
See Vorontsov-Vel'yaminov, B. 1977, Astr. Ap. Suppl., 28, 1
and Korovyakovskaya, A.A. 1983, Astrophysics, 19, 419.
See Barbieri, C., Casini, C., Heidmann, J., Di Serego, S.,
and Zambon, M. 1979, Astr. Ap. Suppl., 37, 559.

6. 1977A&AS...28....1V
Re:VV 523
Plate 24 Prechains and Chains of Different Age
MCG +06-26-060 = Haro 05 = NGC 3991; V=13.19m.
For the bright component V_0_=+3298, for the faint +3033, emissions
lines of Balmer series, [O III], [Ne III], [N II], [O II] (Page
1970). B-V=0.31, U-B=-1.14, also B-V=0.43, U-B=-0.50.
{DELTA}V_0_=265 km s^-1^. The image in the "Palomar Atlas" is very
overexposed.
The photography of VV 523 on plate 69, added at the last moment on
the large 6m telescope of USSR and shows an excellent multinominal
chain. Four of the members are in contact and were considered by Page
to be the "faint component", but between them and the principal compact
companion there is a "bridge", or rather two fainter members in contact.
On the whole the chain contains from 5 to 7 members (the last one is
double). That the leading member is compact and the brightest is
typical for tight chains. VV 523 is the remote member of a triple
system, which contains also the pair VV 249: the very compact peculiar
spiral NGC 3994 (the brightest of the three) and a very distorted large
spiral NGC 3995. All objects are very blue, young, with nearly equal
velocities. The centre of NGC 3995 is akin to NGC 4038/4039 and their
photographs are reproduced in plate 70. All 6m photographs were kindly
obtained by Shabanov and Korovjakovsky. Both objects were discussed by
Vorontsov (1976).

7. 1976RC2...C...0000d
Re:NGC 3991
= Arp 313
= Holm 309c
= Kara[72] 311
= Haro 5 (Bol. Tonantzintla, No. 14, June 1956).
In multiple interacting system with NGC 3994 and NGC 3995.
Photometry:
A.J., 73, 882, 1968.
A.J., 75, 1143, 1970.
Radio Observations:
Nature, 219, 1032, 1968.

8. 1973UGC...C...0000N
Re:UGC 06933
Im pec (de Vaucouleurs)
Haro 5, "muy violeta", (Haro)
See Arp's picture 313
"Double system, bridge" (CGCG)
Very high surface brightness
In triple group with UGC 06936 at 3.8, 160; and UGC 06944 at 3.9, 135, this
pair is VV 249, Arp 313

9. 1964RC1...C...0000d
Re:NGC 3991
= Holm 309c
= Haro 05
Knotty bar-like core with 2 asymmetric bright knots at one end. Peculiar.
Heidelberg Veroff. Vol. 9, 1926 major-axis dimension (0.3 arcmin) is an
error and was rejected
Multiple interacting system with NGC 3994-3995.
Photograph:
Sky & Telescope., 17, 231, 1958.
Spectrum:
P.A.S.P., 69, 564, 1957.
Lick 1962 velocity is for the fainter component: V = +3040 km/sec.

10. 1956BITon..142...8H
Re:Haro 05
Made up of NGC 3991A and NGC 3991B
NGC 3991A:
Very violet.
N1, N2, H{beta}, H{gamma}, H{delta}, H{epsilon},
{lambda}3869, and {lambda}3727.
NGC 3991B:
Decidedly violet.
N1, H{beta}, H{gamma}, {lambda}3869, and {lambda}3727.


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