NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-06-26 T09:21:56 PDT
Help | Comment | NED Home

For refcode 1991AJ....102.1314S:
Retrieve 46 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by American Astronomical Society. Reproduced by permission
1991AJ....102.1314S OPTICAL NEBULOSITY IN X-RAY-SELECTED, EARLY TYPE GALAXIES JOSEPH C. SHIELDS Astronomy Department, University of California, Berkeley, California 94720 Received 6 June 1991; revised 27 June 1991 ABSTRACT Results of an H{alpha} + [N II] narrowband imaging survey of x-ray- selected E and S0 galaxies are presented. A new technique is described for objectively optimizing removal of stellar continuum light while providing well-defined estimates of systematic errors. The procedure has the additional benefit of eliminating sky contamination specifically in image regions occupied by galaxy light. Detailed consideration of the measured spectral energy distributions is included in the flux calibration procedure, and emission-line luminosities (or upper limits), corrected for Galactic foreground extinction, are tabulated for metric apertures. The resulting luminosities for the sample members show no tendency to correlate with x-ray luminosities. Observed H{alpha} + [N II] luminosity (L_H{alpha} + [N II]) does correlate with far-infrared luminosity (L_FIR_), with typical ratios of L_H{alpha} + [N II]_/L_FIR_ that are an order of magnitude below those for late type galaxies. Some tendency is found for L_H{alpha} + [N II]_ to correlate with nonthermal radio power, though this may be due to eccentricities of the sample selection. No connection is apparent between the "boxiness" or "diskiness" of stellar isophotes and emission-line or far-infrared luminosity. Optical nebulosity in early type galaxies probably contains a significant multiparameter dependence on active galactic nuclei behavior, accretion from the hot interstellar medium, and mass injection from external sources. Emission associated with cooling flow phenomena on a galaxy scale may be overwhelmed in many instances by other sources of mass and ionization, suggesting that analogies between nebulosity in these sources and emission in cluster cooling-flow galaxies should be treated with caution.
Retrieve 46 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home