Abstract
CO (J=2->1) observations of six ultraluminous IRAS galaxies are
presented. Four of these galaxies have no previous CO J=2->1 data and
two have no previous CO detections at all. Based on these observations,
molecular hydrogen masses are estimated and range from 5x10^9^ to
1.8x10^10^Msun_. The present data follow the well established
correlation that exists between the infrared luminosity L_IR_ and the
molecular mass content. The high values of the L_IR_/M_H_2__ suggest
either an increased star formation efficiency and / or an additional
source of luminosity such as an active nucleus. The ratio
R=(J=2->1)/(J=1->0) between the J=2->1 and 1->0 line
temperatures, is examined next using our J=2->1 intensities and other
published CO J=1->0 data. For Arp 220, Mrk 231, Mrk 273 R lies in the
range 0.7 to 1.1; for IRAS 05189 the CO intensity and the ratio R were
both found to have extremely low values. The low values of R
Original language | English |
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Pages (from-to) | 747 |
Journal | Astronomy and Astrophysics |
Volume | 305 |
Publication status | Published - 1 Jan 1996 |
Keywords / Materials (for Non-textual outputs)
- GALAXIES: ISM
- GALAXIES: ACTIVE
- RADIO LINES: GALAXIES