Infrared and radio emission from S0 galaxies

Abstract

view Abstract Citations (48) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Infrared and Radio Emission from S0 Galaxies Bally, John ; Thronson, Harley A., Jr. Abstract We have analyzed the 12-100 micron infrared emission from early-type S0 (lenticular) galaxies using the Infrared Astronomical Satellite (IRAS) database. Out of a sample of 74 galaxies, about 30% have been detected in all four IRAS bands and about 80% in at least one band with a signal-to-noise ratio in excess of 3. The distribution of S0 galaxies in the 12 micron/25 micron vs 60 micron/100 micron color-color diagram is similar to the distribution of late-type spiral galaxies, indicating that S0 galaxies have interstellar media that might support ongoing star formation. We identify three different locations for S0 galaxies in a plot of nonthermal continuum versus far-infrared emission: (1) galaxies that follow the infrared/radio relation found for spirals and that may support star formation with a normal initial mass function (IMF); (2) galaxies with excess radio-continuum emission that may contain an active nucleus and extensive nonthermal emission from jets or radio lobes; and (3) a small number of lenticulars with a slight excess of infrared emission, relative to their radio emission. We do not find significant evidence for star formation with a distorted IMF in which only low-mass stars are forming, which is a possible explanation for sources in location (3). Many of the most radio-luminous galaxies are either not detected or are very faint at infrared wavelengths. Although at the high end of the infrared brightness scale some radio emission may be produced as a result of the birth of massive stars and their eventual demise in supernova explosions, most of the strong radio emitters probably resemble the radio-loud elliptical galaxies in which the radio power is ultimately produced by an active nucleus. The absence of strong radio sources among late-type galaxies suggests that the nuclear source of nonthermal emission is smothered by the interstellar medium in these systems. The S0 galaxies are the dividing line between galaxies that produce their radio emission by an active nucleus and those that produce their emission primarily as a by-product of the formation of massive stars and/or a cool interstellar medium. Publication: The Astronomical Journal Pub Date: January 1989 DOI: 10.1086/114957 Bibcode: 1989AJ.....97...69B Keywords: Disk Galaxies; Extragalactic Radio Sources; Galactic Evolution; Infrared Sources (Astronomy); Interstellar Matter; Color-Color Diagram; Infrared Astronomy Satellite; Signal To Noise Ratios; Star Formation; Astrophysics; RADIO SOURCES: GALAXIES; INFRARED: SOURCES; GALAXIES: GENERAL full text sources ADS | data products NED (72) SIMBAD (69)