EVIDENCE FOR A MASSIVE, EXTENDED CIRCUMGALACTIC MEDIUM AROUND THE ANDROMEDA GALAXY*

@inproceedings{Lehner2015EVIDENCEFA,
  title={EVIDENCE FOR A MASSIVE, EXTENDED CIRCUMGALACTIC MEDIUM AROUND THE ANDROMEDA GALAXY*},
  author={Nicolas Lehner and Chris Howk and Bart P. Wakker},
  year={2015}
}
We demonstrate the presence of an extended and massive circumgalactic medium (CGM) around Messier 31 using archival HST Cosmic Origins Spectrograph ultraviolet spectroscopy of 18 QSOs projected within two virial radii of M31 ( kpc). We detect absorption from Si iii at km s−1 toward all three sightlines at , 3 of 4 sightlines at , and possibly 1 of 11 at . We present several arguments that the gas at these velocities observed in these directions originates from the M31 CGM rather than the Local… CONTINUE READING