J/MNRAS/404/1745 Dwarf galaxies in Coma supercluster (Mahajan+, 2010) ================================================================================ Star formation, starbursts and quenching across the Coma supercluster. Mahajan S., Haines C.P., Raychaudhury S. =2010MNRAS.404.1745M ================================================================================ ADC_Keywords: Clusters, galaxy ; Galaxies, photometry ; Photometry, SDSS ; Equivalent widths Keywords: galaxies: clusters: general - galaxies: evolution - galaxies: fundamental parameters - infrared: galaxies Abstract: We analyse Spitzer Multiband Imaging Photometer (MIPS) 24um observations, and Sloan Digital Sky Survey Data Release 7 optical broad-band photometry and spectra, to investigate the star formation (SF) properties of galaxies residing in the Coma supercluster region. We find that SF in dwarf galaxies is quenched only in the high-density environment at the centre of clusters and groups, but that passively evolving massive galaxies are found in all environments, indicating that massive galaxies can become passive via internal processes. The SF-density relation observed for the massive galaxies is weaker relative to the dwarfs, but both show a trend for the fraction of star-forming galaxies (f_SF_) declining to ~0 in the cluster cores. We find that active galactic nucleus activity is also suppressed among massive galaxies residing in the cluster cores. Description: We base our work on the photometric and spectroscopic data acquired by the SDSS Data Release 7 (DR7; Adelman-McCarthy et al., 2006ApJS..162...38A, Cat. II/267), which for the first time covers the entire region of the Coma supercluster presented in this paper. Over a smaller area, we also use archival 24um MIR images, from the MIPS instrument aboard Spitzer (Rieke et al., 2004ApJS..154...25R), available over a significant fraction of the two main clusters. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 61 197 Catalogue of Coma galaxies detected at 24um table3.dat 49 110 Catalogue of dwarf (z>15), k+A [EW(Ha)<2{AA} and EW(Hd)<-3{AA}] galaxies in the Coma supercluster -------------------------------------------------------------------------------- See also: II/267 : The SDSS Photometric Catalog, Release 4 (Adelman-McCarthy+, 2006) http://www.sdss.org : SDSS Home Page Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 8 F8.4 deg RAdeg Rigth ascension in decimal degrees (J2000) 10- 16 F7.4 deg DEdeg Declination in decimal degrees (J2000) 18- 23 F6.4 --- z Spectroscopic redshift 25- 32 F8.5 mag gmag SDSS g magnitude 34- 41 F8.5 mag rmag SDSS r magnitude 43- 50 F8.5 mag zmag SDSS z magnitude 52- 59 F8.4 mJy S24 Spitzer/MIPS 24um flux 61 I1 --- cl [0/3] Classification of galaxy (1) -------------------------------------------------------------------------------- Note (1): Classification on the basis of BPT diagram (Baldwin, Phillips & Terlevich, to distinguish AGN/starburst/HII) as follows: 0 = unclassified 1 = star forming galaxy 2 = AGN 3 = AGN according to Miller et al. (2003ApJ...597..142M) criteria (see text) -------------------------------------------------------------------------------- Byte-by-byte Description of file: table3.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 8 F8.4 deg RAdeg Right ascension in decimal degrees (J2000) 10- 16 F7.4 deg DEdeg Declination in decimal degrees (J2000) 18- 23 F6.4 --- z Spectroscopic redshift 25- 32 F8.5 mag zmag SDSS z magnitude 33- 40 F8.4 0.1nm EW(Ha) H{alpha} equivalent width ({AA}) 42- 49 F8.4 0.1nm EW(Hd) H{delta} equivalent width ({AA}) -------------------------------------------------------------------------------- Nomenclature note: Galaxies identified as [MHR2010] DD.dddd+DD.dddd in Simbad. History: From electronic version of the journal ================================================================================ (End) Patricia Vannier [CDS] 04-Dec-2010