Date and Time of the Query: 2019-06-20 T07:32:38 PDT
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Notes for object NGC 0520

16 note(s) found in NED.

1. 2004AJ....127.3235S
Re:NGC 0520
NGC 520. The flux in this advanced merger appears to be centered between
the two galaxies, in what appears to be a dust lane.

2. 2004A&A...419..501F
Re:NGC 0520
NGC 520 -Br{gamma}line emission in this interacting system is detected
at the primary nucleus within a region of 5" x 3" (Stanford 1991;
Kotilainen et al. 2001). We combined the Br{gamma} flux of Stanford
(1991) in the central 6" x 8" with the H{alpha} flux measured within the
same aperture from an H{alpha} + [N II] map, to derive the extinction.
We made use of the H{alpha}/(H{alpha} + [N II]) ratio of 0.58 found by
Veilleux et al. (1995) at the nucleus. Since the primary nucleus suffers
from very large extinction, the use of H{alpha} photometry in a larger
aperture is especially uncertain.

3. 2000ApJ...541..644X
Re:Arp 157
Arp 157=NGC 520a/b (Figs. 2a-2c): This is a very complex system
apparently involving two (colliding) disk galaxies, one oriented
southeast-northwest (NGC 520a) and another oriented east-west (NGC 520b)
(Stanford 1991; Stanford & Balcells 1990, 1991; Bernlohr 1993a, 1993b).
The collision center appears to lie near the nucleus of NGC 520b, where
the MIR emission peaks. The CO emission also concentrates at this
position (Sanders et al 1988a). The H I gas shows the the kinematic
signature of a rotating disk with the same orientation as NGC 520a,
while the rotation center is clearly at the nucleus of NGC 520b (Hibbard
& van Gorkom 1996). An interesting possibility is that the H I
originally belonged to the former but has been captured by the latter
(which might have an order of magnitude more mass than the former;
Bernlohr 1993b). Note also that both disks show rotation axes nearly
parallel to the axis of the orbital motion (Bernlohr 1993b), making the
hypothesis for migration of the H I gas more reasonable. There is a
second, much weaker peak in the MIR emission associated with the nucleus
of NGC 520a, where new millimeter synthesis observations failed to
detect any CO emission (Hibbard et al. 2000, private communication). The
H{alpha} map (see also Hibbard & van Gorkom 1996; and Young,
Kleinmann, & Allen 1988) shows very different morphology from the MIR
maps which is most likely due to dust extinction of the former. Near the
nucleus of NGC 520b, heavy dust lanes are visible in optical images. The
(f_15 micron_/f_9.7 micron_) ratio, as a rough indicator of silicate
absorption, also peaks there. A NIR K-band image of Arp 157 (Bushouse &
Werner 1990) shows similar morphology to the MIR images, indicating that
the difference between the MIR and optical/H{alpha} morphologies is not
due to different angular resolutions. This is consistent with results of
Bernlohr (1993b), whose model predicts that both NGC 520a and NGC 520b
have been undergoing starbursts, with the starburst associated with
NGC 520a about 2-3 x 10^8^ yr older and a factor of ~8 fainter than the
starburst associated with NGC 520b.

4. 1998MNRAS.297..143R
Re:ARP 157
NGC 520 (Arp 157), seventh in the Toomre sequence, and classified as an
intermediate-stage merger by Hibbard & van Gorkom (1996), is as radio- and
infrared-bright as the Antennae, and has two smaller tails as well as two nuclei
and two veloeity systems in its spectra. indicative of a young merger.

5. 1998A&A...333...38B
Re:NGC 0520
2.2. NGC 520
NGC 520 is a much closer galaxy with some extended CO emission. The IRAS
observations encompass the entire system and thus may mix warm gas in the
central area with somewhat cooler material further out (which probably would not
contribute much to the IRAS fluxes). Nonetheless, the IRAS fluxes are "warm" -
S_60{mu}_/S_100{mu}_~2/3, which is roughly twice the ratio in "normal"
galaxies. Radio data are from Condon et al. (1990) and Urbanik et al. (1985)
who find a synchrotron spectrum of -0.62+/-.06; we have assumed a thermal
fraction of 10% at 10 GHz. In NGC 520, the contributions from CO, synchrotron,
and probably free-free emission are within the normal range.

6. 1996ApJ...466..122R
Re:ARP 157
Arp 157.--Galaxy A appears unobscured, and galaxy C is hidden behind a dust
lane, consistent with their colors. Both are involved in an intense starburst
event. Galaxy A has a partly disturbed r^1/4^ profile. The whole system is a
luminous IRAS source (Young et al. 1989).

7. 1995ApJS...98..477H
Re:NGC 0520
This galaxy shows very obvious tidal features, a highly disturbed
morphology, and prominent dust lanes. Numerical simulations suggest that
NGC 520 is a merger remnant resulting from two disk galaxies colliding
~ 3 x 10^8^ yr ago (Stanford & Barcells 1991), thereby giving rise to the
enhanced star formation observed (Stanford 1991). Our spectra, extracted
over the brightest central knot, most likely coincides with the primary
nucleus, which, according to Stanford (1991), has the most elevated star
formation activity. The emission and absorption features seen in our
spectra are consistent with a very young stellar population.

8. 1994CAG1..B...0000S
Re:NGC 0520
Hubble Atlas, p. 41
Sep 3/4, 1953
103aD + GG11
40 min
The morphology of NGC 520 has always
been described as unusual, not fitting into any
of the morphological boxes of the standard
classification sequence. Hubble (as reported by
Pettit 1954) classified NGC 520 as Irr. Holmberg
(1958) placed NGC 520 into his new Irr II class,
based on the amorphous appearance of its
luminous image, the absence of resolved stars,
and its red color. These are the same features,
along with the dust pattern similar to that in M82
(panels 333, 334) and NGC 3077 (panel 335),
used in classifying the galaxy Amorphous here.
However, the faint plumes on opposite sides
of the center suggest either tidal interaction or,
following Toomre and Toomre (1972), the result
of a merger, as in NGC 4038/4039 (panel 280).
Images of what may be individual stars
appear in the main plume beginning at about
B = 22.5. The redshift is v_o = 2350 km/s. At the
redshift distance of 47 Mpc (H = 50, m - M = 33.4),
the absolute magnitude of such objects is bright,
at M_B_ = -11.

9. 1994CAG1..B...0000S
Re:NGC 0520
Hubble Atlas, p. 41
Nov 28/29, 1935
Imp. Ecl.
60 min
The light print of NGC 520 made from a
plate taken with the Mount Wilson Hooker 100-inch
telescope shows no evidence for the double
nucleus that might be expected from a recent
merger, although some theories suggest that none
need be expected. Based simply on the morphology
of the image, the idea that a merger has
occurred remains an unproved hypothesis.

10. 1993ApJ...412..535W
Re:NGC 0520
NGC 520.-The position of the center of NGC 520 at 10 microns is within 1"
of the peak of the radio source as measured by Condon et al. (1990). NGC
520 is extended by several arcseconds in an east-west direction both at
2.2 microns (Eales et al. 1990) and at radio wavelengths (Condon et al.
1990; Carral, Turner, & Ho 1990). Multiaperture flux density measurements
at 10 microns (Fig. 1) indicate that the object is extended with a scale
length of about 200 pc, consistent with the size implied by the
compactness (Fig. 3). Stanford (1991) has presented independent evidence
that NGC 520 is extended at 10 microns.

11. 1985ApJS...57..643D
Re:VV 231
Strongly distorted spiral, edge-on (aftermath?).

12. 1976RC2...C...0000d
Re:NGC 0520
= Arp 157
= VV 231
= Kara[72] 031
I0 pec or a colliding pair of early spirals.
Description and Classification:
Astrofizika, 3, 427, 1967. A.J., 79, 1242, 1974.
Ap. J., 148, 321, 1967.
Astrofizika, 9, 157, 1973.
Contr. Asiago Obs. No. 300bis, 79, 1973.
Bull. A.A.S., 5, 447, 1973.
Photometry: (2.2 microns, upper limit):
M.N.R.A.S., 164, 155, 1973.
Spectrum and Photograph:
Velocity of nearby blue object (z = 0.116).
Astrofizika, 9, 157, 1973.
Astrofizika, 10, 298, 1974.
Internal Motions:
Astrofizika, 9, 157, 1973.
HI 21cm:
A.J., 79, 767, 1974.
HII Regions:
Ap. J. Suppl. 27, No. 239, 1974.
Radio Observations:
Austral. J. Phys., 21, 193, 1968,
M.N.R.A.S., 167, 251, 1974.

13. 1973UGC...C...0000N
Re:UGC 00966
VV 231, Arp 157
Pec (de Vaucouleurs), Ir II (Holmberg)
Chaotic, diffuse steamer north-preceding
`Inspection of the original plate suggests that NGC 520 is not a collision
of two galaxies but rather a system of the M 82 type' (Sandage)
See UGC 00957

14. 1964RC1...C...0000d
Re:NGC 0520
Nearly edge-on.
Colliding or strongly interacting pair of early-type spirals?
Lick 1962 velocity of [south-preceding]
fainter component is V = +2,857 km/sec (obs.).
(B-V)(0) interpolated.
B(0) from source A only.

15. 1961Hubbl.B...0000S
Re:NGC 0520
Irr II
Sept. 3/4, 1953
103aD + GG11
40 min
Enlarged 4.0X
NGC 0520 has the smooth texture of M82 and has a prominent
absorption patch crossing the face. Thin extensions, of
low surface brightness, are visible in this illustration.
Inspection of the original plate suggest that NGC 0520
is not a collision of two galaxies but rather a system of
the M82 type.

16. 1959VV....C...0000V
Re:VV 231
= NGC 0520
Right photograph from Chandrasekhar,
"Principles of Stellar Dynamics", Chicago, 1942.
Much dust. On (red) POSS print dust and tails look worse.
Similar to VV 188, VV 230, and VV 234.
V = +2,177 km/sec
Yerkes Type: f?Ip

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