Date and Time of the Query: 2019-06-19 T08:19:41 PDT
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Notes for object NGC 2820

8 note(s) found in NED.

1. 2003ApJS..148..383M
Re:NGC 2820
A10. NGC 2820 NGC 2820 is part of an interacting group of galaxies that
consists of NGC 2805-NGC 2814-NGC 2820 and Mrk 108. This is one of only
two galaxies in our sample with obvious interacting companions (the
other is NGC 3432). NGC 2820 was included in our study because radio
continuum data by van der Hulst & Hummel (1985) show a thick disk of
radio emission associated with this object, a possible indication that
EDIG emission may also be present. While no emission has been detected
connecting NGC 2805 to the other galaxies, van der Hulst & Hummel
detected a radio continuum bridge between NGC 2820/ Mrk 108 and
NGC 2814. NGC 2820 is an SB(s)c galaxy with an inclination of 90deg. The
H{alpha}+[N II] image is presented in Figure 10. Two regions of
extraplanar emission (about 2 kpc in height) are observed in the
southeast halo. Fainter emissions extending ~1 kpc up above the disk are
also detected, one in the northwest halo at a distance of ~4.5 kpc
southwest of the galactic center and the other in the southeast halo at
a distance of ~5 kpc northeast of the center (both of which have average
EM 8 pc cm^-6^).
An H{alpha} luminosity /D^2^_25_ of 2.0 x 10^37^ ergs s^-1^ kpc^-2^ is
derived, 16% of which is attributed to extraplanar gas. A
two-exponential fit does not adequately reproduce the extraplanar gas
profile for the southeast halo, but the northwest halo gas has a scale
height of 1.08 kpc and a total extraplanar ionized mass of ~3.3 x 10^7^
M_{sun}_ associated with it. The very strong correlation found between
the southeast halo and disk gas (also evident in Fig. 20) indicates that
the extraplanar emission is strongly tied to the H II regions in the disk
of the galaxy. The large 1 {sigma} deviations of the southeast
extraplanar gas indicates that the emission is not uniform across the
galaxy and confirms that the fiIamentary structure correlates strongly
with the distribution of the H II regions in the disk.

2. 2003ApJ...592...79M
Re:NGC 2820
A4. NGC 2820
NGC 2820 lies at a distance of 20 Mpc, yielding a spatial scale of
00 pc pixel^-1^. The position of the slit was selected on the basis
of the narrowband images reported in Paper I. As discussed in section
3.1.2, NGC 2820 is the only galaxy in our sample where extraplanar
He I/H{alpha} emission has been detected out to |z| ~ 1 kpc. It is
also the only galaxy in which all four main line ratios are detected
out to large vertical heights, therefore providing strong constraints
on the nature of secondary ionization source. The main concern with
NGC 2820 is that the majority of the [O III]/H{alpha} versus
[N II]/H{alpha} data points lie below the photoionization curve. The
TML models with low mixing gas temperatures (log T = 5.0) also have
low [O III]/H{alpha} values. Using this model in conjunction with the
photoionization model, the [O III]/H{alpha} and [O I]/H{alpha} data
suggest that TMLs contribute roughly 35%-55% to the observed line
ratios. Unfortunately, the [S II]/H{alpha} data do not support this
conclusion. The [S II]/H{alpha} data suggest a higher mixing gas
temperature (log T = 5.3), with the contribution to the line ratios
arising from this region apparently increasing with heights from 20%
to 80%. The comparison with the photoionization/shock hybrid model
suggests that the data are best fitted by the model with shock
velocity vs = 100 km s^-1^ and depleted abundance. With the exception
of those [O III]/H{alpha} data points that fall below the
photoionization curve, the remaining data suggest that the ionization
parameter decreases from ~-3.0 to -4.0, while the contribution of
shocks to the line ratios rises from ~10% to 40%. The Dopita &
Sutherland models are perhaps more successful at explaining the
observed trends in the line ratios. The [N II]/H{alpha},
[S II]/H{alpha}, and [O III]/H{alpha} line ratios lie in the region of
the (shock+precursor) model with a magnetic parameter
of ~0 {micro}G cm^3/2^.

3. 2002AJ....124..675C
Re:UGC 04961
The extended NVSS source covers the galaxy triple KTG 23
(Karachentseva et al. 1988) containing UGC 04952, NGC 2820A, and
UGC 04961.

4. 1993A&AS...97..887B
Re:NGC 2820
NGC 2814/2820 are two very different galaxies separated by 4' (27 kpc)
and at the same velocity. They are part of a triplet with IC 2458.
NGC 2805 is only 13' (90 kpc) away and also at a similar velocity. IRAS
data cannot reliably be ascertained for IC 2458 as the centers of IC 2458
and NGC 2820 are only 2' apart, Both galaxies are fairly blue but are
highly extincted. NGC 2814 and IC 2458 are considered as having HII
region-like nuclei and both are detected in H{alpha} with IC 2458 having
a very large equivalent width. our CO observations only yield an upper
limit of about 1 K km/s (for a 100 km/s window) for IC 2458 and several
times this for NGC 2814. NGC 2820 was detected, albeit weakly, in both
lines. The spectra shown only have zero-order baselines subtracted. The
mass of H_2_ implied is slightly over 10^6^ M_sun_ for a distance of 20
Mpc. This is a few percent of the HI mass but only a small portion of the
galaxy has been observed in CO. In IC 750 the CO was strongest off-
center, away from the companion. We cannot rule out something of this
type here but the displacement would have to be greater, in angular
units, meaning a much greater physical displacement in kpc.

5. 1976RC2...C...0000d
Re:NGC 2820
Multiply interacting system with NGC 2805, at 13 arcmin,
and also with NGC 2814 and IC 2458.

6. 1976RC2...C...0000d
Re:NGC 2820
= Holm 124a
Interacting pair with IC 2458 at 2.1 arcmin.
NGC 2814 at 3.7 arcmin.
In a group with NGC 2805.

7. 1973UGC...C...0000N
Re:UGC 04961
SB(s)c pec (de Vaucouleurs), Sc+ (Holmberg)
In contact with 09 17.5 +64 27 = IC 2458 = Mark 108 at 2.0 p, 0.5 x 0.2,
complex, m=15.1, v = 1200, interaction?
See UGC 04936, UGC 04952

8. 1964RC1...C...0000d
Re:NGC 2820
= Holm 124a
Very flat central bulge with dark lanes. Knotty outer arms.
Pair with NGC 2814 at 3.7 arcmin. Pair with NGC 2820A at 2.1 arcmin.
In a group with NGC 2805. Probably interacting with NGC 2820A.
Ap. J., 85, 325, 1937.

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