Four IRAC Sources with an Extremely Red H-[3.6] Color: Passive or Dusty Galaxies at z>4.5?

Дата и время публикации : 2011-10-18T21:26:28Z

Авторы публикации и институты :
J. -S. Huang
X. Z. Zheng
D. Rigopoulou
G. Magdis
G. G. Fazio
T. Wang

Ссылка на журнал-издание: Ссылка на журнал-издание не найдена
Коментарии к cтатье: 15 pages, 3 figures, accepted by ApJ Lett
Первичная категория: astro-ph.CO

Все категории : astro-ph.CO

Краткий обзор статьи: We report detection of four IRAC sources in the GOODS-South field with an extremely red color of H$-$[3.6]$>$4.5. The four sources are not detected in the deep HST WFC3 H-band image with H$_{limit}$=28.3 mag. We find that only 3 types of SED templates can produce such a red H$-$[3.6] color: a very dusty SED with the Calzetti extinction of A$_V$=16 mag at z=0.8; a very dusty SED with the SMC extinction of A$_V$=8 mag at z=2.0$sim$2.2; and an 1Gyr SSP with A$_V sim$0.8 at z=5.7. We argue that these sources are unlikely dusty galaxies at z$leq$2.2 based on absent strong MIPS 24$mu$m emission. The old stellar population model at z$>$4.5 remains a possible solution for the 4 sources. At z$>$4.5, these sources have stellar masses of Log(M$_*$/M$_{odot}$)=10.6$sim$11.2. One source, ERS-1, is also a type-II X-ray QSO with L$_{2-8keV}$=1.6$times 10^{44}$ erg s$^{-1}$. One of the four sources is an X-ray QSO and another one is a HyperLIRG, suggesting a galaxy-merging scenario for the formation of these massive galaxies at high redshifts.

Category: Physics