No evidence of obscured, accreting black holes in most z=6 star-forming galaxies

Дата и время публикации : 2011-10-18T20:31:25Z

Авторы публикации и институты :
Chris J. Willott

Ссылка на журнал-издание: Ссылка на журнал-издание не найдена
Коментарии к cтатье: 4 pages, 2 figures, ApJ Letters, in press
Первичная категория: astro-ph.CO

Все категории : astro-ph.CO

Краткий обзор статьи: It has been claimed that there is a large population of obscured, accreting black holes at high-redshift and that the integrated black hole density at z=6 as inferred from X-ray observations is ~100 times greater than inferred from optical quasars. I have performed a stacking analysis of very deep Chandra X-ray data at the positions of photometrically-selected z=6 galaxy candidates. It is found that there is no evidence for a stacked X-ray signal in either the soft (0.5-2 keV) or hard (2-8 keV) X-ray bands. Previous work which reported a significant signal is affected by an incorrect method of background subtraction which underestimates the true background within the target aperture. The puzzle remains of why the z=6 black hole mass function has such a flat slope and a low normalization compared to the stellar mass function.

Category: Physics