The ACS fornax cluster survey. II. The Central brightness profiles of early-type galaxies: A Characteristic radius on nuclear scales and the transition from central luminosity deficit to excess

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dc.contributor.author Cote, Patrick
dc.contributor.author Ferrarese, Laura
dc.contributor.author Jordan, Andres
dc.contributor.author Blakeslee, John
dc.contributor.author Chen, Chin
dc.contributor.author Infante, Leopoldo
dc.contributor.author Merritt, David
dc.contributor.author Mei, Simona
dc.contributor.author Peng, Eric
dc.contributor.author Tonry, John
dc.contributor.author West, Andrew
dc.contributor.author West, Michael
dc.date.accessioned 2008-11-10T18:12:18Z
dc.date.available 2008-11-10T18:12:18Z
dc.date.issued 2007-12-20
dc.identifier.citation Astrophysical Journal 671 (2008) 1456-1465 en_US
dc.identifier.uri http://hdl.handle.net/1850/7396
dc.description Also archived in: arXiv:0711.1358 v1 Nov 8 2007 en_US
dc.description.abstract We analyse brightness profiles for 143 early-type galaxies in the Virgo and Fornax Clusters, observed with the Advanced Camera for Surveys on the Hubble Space Telescope. S´ersic models are found to provide accurate representations of the global profiles with a notable exception: the observed profiles deviate systematically inside a characteristic “break” radius of Rb ≈ 0.02+0.025 −0.01 Re, where Re is the effective radius of the galaxy. The sense of the deviation is such that bright galaxies (MB . −20) typically show central light deficits with respect to the inward extrapolation of the S´ersic model, while the great majority of low- and intermediate-luminosity galaxies (−19.5 . MB . −15) show central light excesses; galaxies of intermediate luminosities (−20 . MB . −19.5) are generally well fitted by S´ersic models over all radii. We show that the slope, ′, of the central surface brightness profiles, when measured at fixed fractions of Re, varies smoothly as a function of galaxy luminosity in a manner that depends sensitively on the choice of measurement radius. We find no evidence for a core/power-law dichotomy, and show that a recent claim of strong bimodality in ′ is likely an artifact of the biased galaxy selection function used in that study. To provide a more robust characterization of the inner regions of galaxies, we introduce a parameter, 0.02 = log (Lg/Ls) — where Lg and Ls are the integrated luminosities inside 0.02Re of the observed profile and of the inward extrapolation of the outer S´ersic model — to describe the central luminosity deficit ( 0.02 < 0) or excess ( 0.02 > 0). We find that 0.02 varies smoothly over the range of ≈ 720 in luminosity spanned by the sample galaxies, with again no evidence for a dichotomy. We argue that the central light excesses in MB & −19 galaxies may be the analogs of the dense central cores predicted by some numerical simulations to form via gas inflows. en_US
dc.language.iso en_US en_US
dc.publisher Universtiy of Chicago Press: Astrophysical Journal en_US
dc.relation.ispartofseries vol. 671 en_US
dc.relation.ispartofseries no. 2 en_US
dc.relation.ispartofseries pps. 1456-1465 en_US
dc.subject Galaxies en_US
dc.subject Clusters - invidual (Virgo, Fornax) en_US
dc.subject Galaxies - elliptical and lenticular, cD en_US
dc.subject Galaxies - nuclei en_US
dc.subject Galaxies - structure en_US
dc.title The ACS fornax cluster survey. II. The Central brightness profiles of early-type galaxies: A Characteristic radius on nuclear scales and the transition from central luminosity deficit to excess en_US
dc.type Article en_US

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