TY - JOUR
T1 - On the distribution of stellar masses in gamma-ray burst host galaxies
AU - Castro Cerón, José María
AU - Michalowski, Michal
AU - Hjorth, Jens
AU - Malesani, Daniele
AU - Gorosabel, J.
AU - Watson, Darach Jafar
AU - Fynbo, Johan Peter Uldall
AU - Calderon, C. M.
N1 - Paper id:: arXiv:0803.2235v2
PY - 2010/10/1
Y1 - 2010/10/1
N2 - We analyze Spitzer images of 30 long-duration gamma-ray burst (GRB) host galaxies.We estimate their total stellar masses (M*) based on the rest-frame K-band luminosities (LKrest ) and constrain their star formation rates (SFRs; not corrected for dust extinction) based on the rest-frame UV continua. Further, we compute a mean M*/ LKrest = 0.45M⊙/L⊙. We find that the hosts are low M*, star-forming systems. The median M* in our sample (<M*> = 109.7M⊙) is lower than that of "field" galaxies (e.g., Gemini Deep Deep Survey). The range spanned by M* is 107M⊙ < M* < 1011M⊙, while the range spanned by the dust-uncorrected UV SFR is 10-2M⊙ yr-1 < SFR < 10M⊙ yr-1. There is no evidence for intrinsic evolution in the distribution of M* with redshift. We show that extinction by dust must be present in at least 25% of the GRB hosts in our sample and suggest that this is a way to reconcile our finding of a relatively lower UV-based, specific SFR (ø = SFR/M *) with previous claims that GRBs have some of the highest ø values. We also examine the effect that the inability to resolve the star-forming regions in the hosts has on ø
AB - We analyze Spitzer images of 30 long-duration gamma-ray burst (GRB) host galaxies.We estimate their total stellar masses (M*) based on the rest-frame K-band luminosities (LKrest ) and constrain their star formation rates (SFRs; not corrected for dust extinction) based on the rest-frame UV continua. Further, we compute a mean M*/ LKrest = 0.45M⊙/L⊙. We find that the hosts are low M*, star-forming systems. The median M* in our sample (<M*> = 109.7M⊙) is lower than that of "field" galaxies (e.g., Gemini Deep Deep Survey). The range spanned by M* is 107M⊙ < M* < 1011M⊙, while the range spanned by the dust-uncorrected UV SFR is 10-2M⊙ yr-1 < SFR < 10M⊙ yr-1. There is no evidence for intrinsic evolution in the distribution of M* with redshift. We show that extinction by dust must be present in at least 25% of the GRB hosts in our sample and suggest that this is a way to reconcile our finding of a relatively lower UV-based, specific SFR (ø = SFR/M *) with previous claims that GRBs have some of the highest ø values. We also examine the effect that the inability to resolve the star-forming regions in the hosts has on ø
U2 - 10.1088/0004-637X/721/2/1919
DO - 10.1088/0004-637X/721/2/1919
M3 - Journal article
SN - 0004-637X
VL - 721
SP - 1919
EP - 1927
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
ER -