NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2018-12-13 T10:23:53 PST
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For refcode 2005MNRAS.360..587B:
Retrieve 222 NED objects in this reference.
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NED Abstract

Copyright by Royal Astronomical Society. 2005MNRAS.360..587B Near-infrared imaging of 222 nearby Hdelta-strong galaxies from the Sloan Digital Sky Survey Balogh, Michael L.; Miller, Chris; Nichol, Robert; Zabludoff, Ann; Goto, Tomo Abstract. We present UFTI K-band imaging observations of 222 galaxies that are selected from the Sloan Digital Sky Survey to have unusually strong Hdelta absorption equivalent widths, W_o_(Hdelta) > 4 A. Using GIM2D, the images are fitted with two-dimensional surface-brightness models consisting of a simple disc and bulge component to derive the fraction of luminosity in the bulge B/T. We find that the galaxies with weak or absent H{alpha} or [OII]{lambda}3727 emission (known as k+a galaxies) are predominantly bulge-dominated (with a mode of B/T~ 0.6), while galaxies with nebular emission [known as e(a) galaxies] are mostly disc-dominated (B/T~ 0.1). The morphologies and (r-k) colours of most k+a galaxies are inconsistent with the hypothesis that they result from the truncation of star formation in normal, spiral galaxies. However, their (u-g) and (r-k) colours, as well as their H{delta} line strengths, form a sequence that is well matched by a model in which >5 per cent of the stellar mass has been produced in a recent starburst. The lack of scatter in the dust-sensitive (r-k) colours suggests that the unusual spectra of k+a galaxies are not due to the effects of dust. The e(a) galaxies, on the other hand, have a colour distribution that is distinct from the k+a population, and typical of normal or dusty ({tau}_V_~ 2) spiral galaxies. We conclude that many e(a) galaxies are not progenitors of k+a galaxies, but are a separate phenomenon. Both k+a and e(a) galaxies reside in environments (characterized by the local density of galaxies brighter than M_r_=-20) that are typical of normal galaxies and that are inconsistent with overdense regions like rich galaxy clusters.
Retrieve 222 NED objects in this reference.
Please click here for ADS abstract

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