NEAR-INFRARED OBSERVATIONS OF IRAS-09104+4109

Near infrared imaging and grism spectroscopy of the high luminosity in frared bright galaxy IRAS 09104+4109 have been obtained with the W. M. Keck Telescope. The imaging shows 6 ''knots'' of emission projected a gainst the extended stellar envelope of the cD galaxy thought to be th e source of the large far infrared luminosity. The luminosities of the knots are consistent with the bulges of galaxies accreting onto the c entral galaxy. In addition, there are 11 companion galaxies seen at ra dii of 40-150 kpc from the cD nucleus. These objects have colors in th e range R-K similar to 3.5+/-0.5 mag, J-H similar to 0.9+/-0.2 mag and H-K similar to 0.7+/-0.2 mag, which are consistent with galaxies at a redshift of 0.4. The companion galaxies have luminosities comparable to or less than the characteristic luminosity (L) of field galaxies. While the central cD galaxy is identified with the luminous infrared s ource, it appears to be a quiescent, radio-quiet galaxy, showing no ev idence from its near infrared colors for a highly reddened nucleus as seen in other infrared luminous galaxies. The grism spectroscopy shows forbidden lines of low ionization stages of sulfer, iron, and oxygen, as well as hydrogen recombination lines and a strong line of neutral helium. A visual extinction of A(upsilon)similar to 2 mag is derived t o the narrow line region surrounding the galaxy nucleus, based on the line ratios [S II]1.03 mu m/0.407 mu m and P delta/H beta. The near in frared spectrum is consistent with the optical classification of this system being a Seyfert 2 nucleus. (C) 1996 American Astronomical Socie ty.