paper

A Measurement of the Rate of Type Ia Supernovae in Galaxy Clusters from the SDSS-II Supernova Survey

arXiv:1003.1521 · doi:10.1088/0004-637X/715/2/1021

Abstract

ABRIDGED We present measurements of the Type Ia supernova (SN) rate in galaxy clusters based on data from the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. The cluster SN Ia rate is determined from 9 SN events in a set of 71 C4 clusters at z <0.17 and 27 SN events in 492 maxBCG clusters at 0.1 < z < 0.3 $. W e f in d v a l u es f or t h ec l u s t er S N I a r a t eo f$ ({0.37}^{+0.17+0.01}_{-0.12-0.01}) \mathrm{SNu}r h^{2} $an d$ ({0.55}^{+0.13+0.02}_{-0.11-0.01}) \mathrm{SNu}r h^{2} $($ \mathrm{SNu}x = 10^{-12} L_{x\sun}^{-1} \mathrm{yr}^{-1} $) in C 4 an d ma x B C G c l u s t er s, r es p ec t i v e l y, w h er e t h e q u o t e d er r or s a r es t a t i s t i c a l an d sy s t e ma t i c, r es p ec t i v e l y . T h e S N r a t e f or e a r l y - t y p e g a l a x i es i s f o u n d t o b e$ ({0.31}^{+0.18+0.01}_{-0.12-0.01}) \mathrm{SNu}r h^{2} $an d$ ({0.49}^{+0.15+0.02}_{-0.11-0.01})\mathrm{SNu}r h^{2} $in C 4 an d ma x B C G c l u s t er s, r es p ec t i v e l y . T h e S N r a t e f or t h e b r i g h t es t c l u s t er g a l a x i es (B C G) i s f o u n d t o b e$ ({2.04}^{+1.99+0.07}_{-1.11-0.04}) \mathrm{SNu}r h^{2} $an d$ ({0.36}^{+0.84+0.01}_{-0.30-0.01}) \mathrm{SNu}r h^{2} $in C 4 an d ma x B C G c l u s t er s . T h er a t i oo f t h e S N I a r a t e in c l u s t er e a r l y - t y p e g a l a x i es t o t ha t o f t h e S N I a r a t e in f i e l d e a r l y - t y p e g a l a x i es i s$ {1.94}^{+1.31+0.043}_{-0.91-0.015} $an d$ {3.02}^{+1.31+0.062}_{-1.03-0.048} $, f or C 4 an d ma x B C G c l u s t er s . T h e S N r a t e in g a l a x y c l u s t er s a s a f u n c t i o n o f r e d s hi f t ... s h o w so n l y w e ak d e p e n d e n ceo n r e d s hi f t . C o mbinin g o u r c u r r e n t m e a s u r e m e n t s w i t h p r e v i o u s m e a s u r e m e n t s, w e f i tt h ec l u s t er S N I a r a t e d a t a t o a l in e a r f u n c t i o n o f r e d s hi f t, an df in d$ r_{L} = [(0.49^{+0.15}_{-0.14}) +(0.91^{+0.85}_{-0.81}) \times z]\mathrm{SNu}Bh^{2} $. A co m p a r i so n o f t h er a d ia l d i s t r ib u t i o n o f S N e in c l u s t er t o f i e l d e a r l y - t y p e g a l a x i ess h o w s p oss ib l ee v i d e n ce f or an e nhan ce m e n t o f t h e S N r a t e in t h ecor eso f c l u s t er e a r l y - t y p e g a l a x i es ... w ees t ima t e t h e f r a c t i o n o f c l u s t er S N e t ha t a r e h os tl ess t o b e$ (9.4^+8._3-5.1)%$.

46 pages. ApJ in press. v2 fixes some references.