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For refcode 1991ApJ...379..177L:
Retrieve 24 NED objects in this reference.
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1991ApJ...379..177L MOLECULAR GAS IN ELLIPTICAL GALAXIES JOANNA F. LEES AND G. R. KNAPP Peyton Hall, Princeton University Observatory, Princeton, NJ 08544 MICHAEL P. RUPEN Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 AND T. G. PHILLIPS Downs Laboratory of Physics, 320-47, California Institute of Technology, Pasadena, CA 91125 Received 1990 October 19; accepted 1991 April 3 ABSTRACT Observations of 24 early-type galaxies, mostly far-infrared (FIR)-bright ellipticals, in the ^12^CO(2-1) emission line resulted in 10 detections including eight out of the 20 ellipticals. Eight of these galaxies have not previously been detected. A search of the literature reveals a total of 17 elliptical galaxies, including our eight detections, with observed molecular gas, as well as 27 upper limits. Thus, our study almost doubles the number of elliptical galaxies detected in CO emission. The detected ellipticals have typical molecular gas masses of about 10^7^-10^8^ M_sun_, similar to their H I masses, and an approximately power-law distribution of M_H2_/LB (in contrast to the Gaussian distribution for later type galaxies), extending to much lower values than for the spirals. The lenticular galaxies have CO properties intermediate between the elliptical and spiral systems. The 27 early-type galaxies which are detected in both molecular and atomic gas have the same mean ratio of molecular to atomic gas mass as later type spirals (albeit with a larger dispersion), similar ratios of H{alpha} luminosity and FIR luminosity to molecular gas mass, and identical FIR colors. Thus, these (mostly FIR-bright) ellipticals seem to have global interstellar medium properties similar to those in late-type galaxies, but on a much smaller scale. A comparison of the properties of those ellipticals which have been detected in Co with the undetected galaxies indicates that the molecular gas may occur preferentially in the bluer, lower luminosity dwarf ellipticals, which have more than twice the detection rate of the brighter galaxies. Both the detected and undetected ellipticals are at the same mean distance; however, it may be more difficult to detect gas in bright galaxies because of their larger line widths. Further study of the bright ellipticals is needed to verify this conclusion. The detected ellipticals also tend to be much brighter in the far-infrared, implying the presence of cold dust and/or star formation associated with the molecular gas. Our high detection rate, and the power-law distribution of M_H2_/LB, implies that most FIR-bright ellipticals probably contain a molecular interstellar medium. For those ellipticals in which molecular gas is detected, the lack of correlation between the molecular gas mass and the blue luminosity argues for an external origin for this gas. Subject headings: galaxies: interstellar matter - interstellar: abundances - interstellar: molecules ========================================================================= 1992ApJ...396..741L ERRATUM In the paper "Molecular Gas in Elliptical Galaxies" by Joanna F. Lees, G. R. Knapp, Michael P. Rupen, and T. G. Phillips (ApJ, 379,177 [1991]), an error appeared on page 208. Two numbers which were quoted from Young and Knezek (1989) were inadvertently not converted from their CO-H_2_ conversion factor to ours (a difference of 40%). Page 208, column (1), lines 6-7 should read: "... and that of Young & Knezek (1989) of 2.0{alpha} for a larger galaxy sample." Page 208, column (1), lines 33-34 should read: "... they find a mean value of M_H2_/L_B_ of 0.46{alpha} ... " We would like to thank Dr. Judy Young for pointing out this error.
Retrieve 24 NED objects in this reference.
Please click here for ADS abstract

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