We present high spatial resolution X-ray imaging data for the interacting galaxy pair NGC 7714/5 ( Arp 284 ) from the Chandra X-ray telescope .
In addition to the unresolved starburst nucleus , a variable point source with L _ { X } \approx 10 ^ { 40 } erg s ^ { -1 } was detected 1 . ^ { \prime \prime } 5 ( 270 pc ) to the northwest of the nucleus , coincident with a blue , extremely optically-luminous ( M _ { V } \approx - 14.1 ) point source on HST images .
Eleven other candidate point-like ultraluminous X-ray sources ( ULXs ) were also detected in the vicinity of NGC 7714/5 , two of which exceed 10 ^ { 40 } erg s ^ { -1 } .
Ten of these appear to be associated with interaction-induced features but only two with star formation regions .
We also found diffuse emission with L _ { X } \approx 3 \times 10 ^ { 40 } erg s ^ { -1 } extending 11 ^ { \prime \prime } ( 1.9 kpc ) to the north of the nucleus .
Its spectrum can be fit with either a 2-temperature Mekal function ( kT = 0.59 \pm ^ { 0.05 } _ { 0.06 } keV and 8 \pm ^ { 10 } _ { 3 } keV ) , or a 0.6 keV Mekal function plus a power law ( \Gamma = 1.8 \pm 0.2 ) .
The hard component may be due to high mass X-ray binaries ( HMXBs ) with possible contributions from inverse Compton radiation , while the soft component is likely from a superwind .
Superbubble models imply an expansion age of \approx 15 Myr , supporting previous assertions of an intermediate-age nuclear stellar population in addition to a 5 Myr starburst .
We also detected extended X-ray emission associated with four extra-nuclear HII region complexes .
The emission from these HII regions and the nuclear starburst could be due to either an enhanced population of HMXBs relative to Local Group galaxian averages , or to diffuse gas heated by winds from supernovae , if the X-ray production efficiency L _ { X } /L _ { mech } is high ( \approx 5 \% ) .
To estimate L _ { X } /L _ { mech } , we collected published data for well-studied HII regions and superbubbles in nearby galaxies .
For HII regions with ages < 3.5 Myrs , the median L _ { X } /L _ { mech } \approx 0.02 \% , while for older star formation regions , L _ { X } /L _ { mech } \approx 0.2 - 7 \% .
Thus it is possible that gas heating by supernovae may be sufficient to account for the observed X-rays from these HII regions .
In galaxies much more distant than NGC 7714 , for example , the Cartwheel galaxy , HII region complexes similar to those in NGC 7714 will be unresolved by Chandra , and will mimick ULXs .
No X-ray emission was detected from the Type Ib supernova SN 1999dn , with an upper limit of \approx 2 \times 10 ^ { 38 } erg s ^ { -1 } .