Bibcode
Stanga, R. M.; Mannucci, F.; Rodríguez Espinosa, J. M.
Bibliographical reference
In NASA. Ames Research Center, The Evolution of Galaxies and Their Environment p 317-318 (SEE N93-26706 10-90)
Advertised on:
1
1993
Citations
0
Refereed citations
0
Description
UGC 5101 (z = 0.04; D is approximately equal to 240 Mpc) is one of the
so called Ultraluminous IRAS sources. Two important properties of the
members of this group are their L(sub IR) is greater than or equal to
10(exp 12) solar luminosity, and their space density in the universe up
to z is less than 0.1 is equal or even larger than the space density of
the quasars. Further noteworthy features of the Ultraluminous IRAS
sources are their being morphologically peculiar and the fact that they
all seem to host active nuclei in their center. We have observed UGC
5101 in an effort to study the interplay between the gas ionized by the
central active nucleus and that gas ionized by other processes which may
hold important clues to the understanding of the entire picture of this
object. In particular these other ionizing processes could well be
massive stars formed recently after the galactic encounter and shocks
possibly also related to the galaxy collision. The data that we discuss
were obtained between Dec. 1989 and Jan. 1992 with the WHT 4.2 m
telescope using the two-arm spectrograph ISIS. Several spectral frames
were obtained at three different position angles: PA 84--along the tail
of the galaxy; PA 32--along the dust lane; and PA 110. The blue spectra
are centered on the H beta line, while the red spectra are centered on
the H alpha line. In the configuration we used for the long slit
spectra, the spectral scale was 0.74 A per pixel, and the spatial scale
was .37 arcsec per pixel; we also observed the H alpha region with a
spectral scale of .37 A per pixel, at position angle 84. The narrow band
images were obtained at the auxiliary port of ISIS, with a scale of .2
arcsec per pixel, and were centered at the H alpha wavelength, and on
the adjacent continuum. The H alpha images and the spectra support the
following model. UGC 5101 hosts an active nucleus; the NLR extends up to
about 1.5 kpc and shows a complex velocity field, superimposed on the
rotation curve of the galaxy. Besides the NLR, in the H alpha image are
visible tow bright cones that extend up to 3 kpc along PA 32. The long
slit spectra at PA 32 show that the velocity field of the gas in these
regions is peculiar, while the ionization structure of the gas is
similar to that of the NLR.