A candidate intermediate-mass black hole in the dwarf starburst galaxy He 2-10

A candidate accreting black hole (BH) with M_BH virgul 10^6 M_sun has recently beenidentified in the local dwarf starburst galaxy Henize 210. This discoveryraises the possibility of an entirely new environment for such black holes andhas important implications for the overall population of massive BHs and theprocesses by which seed BHs formed and grew in the early Universe. The hardXray nucleus of He 210 was detected with Chandra in 2001, but its variabilityproperties are completely unknown and its hard Xray spectrum is not wellcharacterized. We propose a 25 ks XMM exposure to search for variability and foran improved measurement of the Xray spectrum, in order to test the hypothesisthat it is an accreting BH and place some constraints on its mass. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]