Young Accreting Compact Objects in M31: The Combined Power of NuSTAR, Chandra, and Hubble

Understand

We present 15 high mass X-ray binary (HMXB) candidates in the disk of M31 for which we are able to infer compact object type, spectral type of the donor star, and age using multiwavelength observations from NuSTAR, Chandra, and the Hubble Space Telescope (HST).

• The hard X-ray colors and luminosities from NuSTAR permit the tentative classification of accreting X-ray binary systems by compact object type, distinguishing black hole from neutron star systems.
• We find hard state black holes, pulsars, and non-magnetized neutron stars associated with optical point source counterparts with similar frequency.
• We also find nine non-magnetized neutron stars coincident with globular clusters and an equal number of pulsars with and without point source optical counterparts.