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Date and Time of the Query: 2019-06-16 T15:48:03 PDT
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For refcode 1988AJ.....96..867C:
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Copyright by American Astronomical Society. Reproduced by permission
1988AJ.....96..867C SPECTROSCOPIC OBSERVATIONS OF MAGNESIUM ABSORPTION GRADIENTS IN SIX ELLIPTICAL GALAXIES JEAN COUTURE AND EDUARDO HARDY Departement de Physique and Observatoire du Mont Megantic, Universite Laval, Sainte-Foy, Quebec G1K 7P4, Canada Received 23 February 1988;revised 17 May 1988 ABSTRACT We present Mg_2_ absorption strengths for six early-type galaxies obtained with Mont Megantic's long-slit spectrograph and a panoramic photon-counting detector system (LIPS). The gradients have been measured to more than one effective radius for NGC 1052, 3379, 4365, 4406, 4621, and 7332 along the major axis and, in three cases, also along the minor axis. The data are presented in tabular and graphical form. The spectral variations have been mapped in two different adimensional radial coordinate systems, (r/r_e_)^1/4^ (which is proportional to surface brightness for galaxies following de Vaucouleurs' law) and log (r/r_e_). The gradients were found to be very similar for a given representation for all galaxies studied. Our gradients are also similar to those derived from a representation of the available published data in the same coordinate systems. When all available samples are combined, we obtain mean slope values given by d Mg_2_/d (r/r_e_)^1/4^ = -0.14 +/- 0.01 (1{sigma}) and d Mg_2_/d log (r/r_e_) = d Mg_2_/d log r = -0.06 +/- 0.01 (1{sigma}). These slopes can be considered as scaling relations to be explained by theories of galaxy formation. Using the currently available abundance versus Mg_2_ strength calibrations, we confirm that abundance varies by a factor ~2 within one effective radius for giant early-type galaxies.
Retrieve 11 NED objects in this reference.
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