Spectral synthesis of metallicity gradients in bright early-type galaxies

Abstract

view Abstract Citations (12) References (24) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Spectral Synthesis of Metallicity Gradients in Bright Early-Type Galaxies Couture, Jean ; Hardy, Eduardo Abstract The main question posed in this investigation is whether spectral synthesis methods confirm the metallicity gradient suggested by the observed Mg_2_ gradients. To this end we apply the method of optimized spectral population synthesis to spatially resolved spectroscopic data for a sample of six bright early-type galaxies. The data were obtained at Mont Megantic with a panoramic photon-counting system (LIPS) and cover the 4800-5500 A spectral interval and a spatial interval of more than one effective radius. We find an overall trend of decreasing metallicity with radial distance which can be expressed as {DELTA} [Fe/H]/{DELTA}(r/r_e_)^1/4^ = -0.76 +/- 0.29 (s.e.) for the mean of our sample. The statistical significance of this mean metallicity gradient is lower than that of the mean Mg_2_, gradient obtained by Couture and Hardy (1988), but consistent with the adopted [Fe/H] vs Mg_2_ calibration employed there. Our results lend confidence to the conclusion that Mg_2_ gradients are controlled mainly by metallicity. The requirements, limitations, and possible improvements of the method employed here are discussed. Publication: The Astronomical Journal Pub Date: February 1990 DOI: 10.1086/115348 Bibcode: 1990AJ.....99..540C Keywords: Early Stars; Elliptical Galaxies; Galactic Structure; Metallicity; Spectral Methods; Brightness; Galactic Evolution; Surface Properties; Astrophysics; GALAXIES: GENERAL full text sources ADS | data products SIMBAD (6) NED (6)