NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-03-18 T21:01:35 PDT
Help | Comment | NED Home

Notes for object IC 4764

2 note(s) found in NED.


1. 1995A&AS..113...35A
Re:DC 1842-630:[D80] 008
DC 8: The H{alpha} emission of this galaxy is very faint and the Signal
to Noise ratio was inadequate on our first exposure of 2^h^15^m^ in 1992
especially since our interference filter was not optimum for its redshift
(see Table 1). It was observed again in 1993 with a longer exposure
(3^h^20^m^), but we could measure velocities and draw the velocity field
displayed in Fig. 1 only after a strong smoothing of the profiles
(gaussian smoothing of 30 km s^-1^ FWHM in wavelength and 2 x 2 pixels on
the image).
Our rotation curve is much lower than RWF but this may be due in part
to our strong smoothing diminishing the gradient in the rising part of
the curve. No OG value can be derived since we do not go far enough. The
OG value given by RWF is not reliable because of the necessary
extrapolation. Furthermore, their outermost point is isolated and found
at 24 arcsec to the Southeast, which is the location of a companion
galaxy clearly seen on the photograph as well as on the continuum
isophotes of Fig. 1. Since this measurement was only made in a [NII]
line, we tried to observe DC8 with a filter centered at 6670 A (see Table
1), thus selecting the redshifted 6584 A [NII] line. The exposure was
stopped after 1^h^20^m^ because of clouds, but in that time we did not
detect any emission at that wavelength.
The high inclination of DC8, together with the necessary smoothing of
our profiles, did not allow us to determine the inclination accurately.
We adopted the same value 75^deg^ as RWF. We found a systemic velocity at
3760 km s^-1^ instead of their 3650 km s^-1^. This large difference is
quite surprising since the agreement is good for all other galaxies of
the cluster as can be seen in Table 2.
The main result about DC 8 is that in contradiction to what RWF found
our curve does not decrease at large radii.

2. 1982ESOU..C...0000L
Re:ESO 184222-6332.3
=ESO 104- G 04
in cluster


Back to NED Home