We present results from Chandra observations of the X-ray starburst galaxies NGC3310 and NGC2276. We detect 27 discrete sources in NGC3310, and 19 discrete sources in NGC2276 with luminosities above 1.0x10^38^erg/s. The majority of the sources have photon indices of 1.7-2.0, typical for X-ray binaries. Both galaxies have large numbers of ultra-luminous X-ray sources (ULXs; sources with L(0.3-10.0keV)>10^39^erg/s), 14 for NGC3310 concentrated on the circumnuclear star-forming ring and north spiral arm and 11 for NGC2276 with the brighter ones on the west side of the galaxy which is compressed due to harassment by the intra-group medium it is moving into. We find for both galaxies that the ULX-hosting areas are located above the general LX-SFR scaling relations while other areas either follow or fall below the scaling relations. This indicates that sub-galactic regions follow the galaxy-wide scaling relations but with much larger scatter resulting from the age (and possibly metallicity) of their local stellar populations in agreement with recent theoretical and observational results. Such differences in age could be the origin of the scatter we observe in the low-SFR regime in the Lx-SFR scaling relations.

Cone search capability for table J/MNRAS/483/711/table1 (Broad-band (0.5-7.0keV) photometry of the discrete sources in NGC 3310)

Cone search capability for table J/MNRAS/483/711/table2 (Broad-band (0.5-7.0keV) photometry of the discrete sources in NGC 2276)