Comparing GC and Field LMXBs in Elliptical Galaxies with deep Chandra and Hubble data

Understand

(abridged) We present a statistical study of the low-mass X-ray binary (LMXB) populations of three nearby, old elliptical galaxies: NGC 3379, NGC 4278, and NGC 4697.

• With a cumulative ~1 Ms Chandra ACIS observing time, we detect 90-170 LMXBs within the D25 ellipse of each galaxy.
• Cross-correlating Chandra X-ray sources and HST optical sources, we identify 75 globular cluster (GC) LMXBs and 112 field LMXBs.
• In the low luminosity range allowed by our deeper data (LX < 5 x 1037 erg s-1), we find a significant relative lack of GC-LMXBs, when compared with field sources.