X-Rays from Blue Compact Dwarf Galaxies

摘要: We measured the X-ray fluxes from an optically selected sample of blue compact dwarf galaxies (BCDs) with metallicities <0.07 and solar distances less than 15 Mpc. Four point sources were observed in three galaxies, five having no detectable emission. Comparing luminosity star formation rate (SFR), we find that total is more 10 times greater expected if scales SFR according to relation found for normal-metallicity star-forming galaxies. However, due low number detected, one can exclude hypothesis binaries low-metallicity BCDs identical normal only at 96.6% confidence level. It has recently been proposed important source heating reionization intergalactic medium epoch reionization. If are analogs unevolved early universe, then enhanced binary production would suggest impact on thermal history universe.