ROSAT X-ray observations of the interacting pair of galaxies NGC 4410: evidence for a central starburst

We present X-ray observations of the interacting pair of galaxies NGC 4410a /b with the ROSAT HRI and PSPC. The ROSAT HRI images reveal a point-like so urce corresponding to NGC 4410a and an X-ray halo, extending 10 " from the nucleus toward the southeast. The halo emission accounts for similar to 1/3 (L-X = 1.3 x 10(41) erg s(-1) in the 0.1-2.4 keV ROSAT band) of the total X-ray emission detected from NGC 4410a. The spectrum of the total X-ray emi ssion from NGC 4410a can be fitted at best with a two-component emission mo del, combining a Raymond-Smith spectrum with T = 10(7) K and a power-law sp ectrum (Gamma = 2.2). The fraction of the thermal component to the total fl ux within this model is 35 %, supporting the results of the HRI observation . The total unresolved X-ray luminosity detected with the PSPC amounts to 4 x10(41) erg s(-1) in the ROSAT PSPC band (for D = 97 Mpc). A preferable explanation might be the interaction between the two galaxies causing a circumnuclear starburst around the active nucleus in the peculiar late type Sab galaxy NGC 4410a. As a cumulative effect of exploding stars a superbubble forms a bipolar outflow from the galactic disk with an expans ion time of similar to 8 Myr. The central source injects mechanical energy at a constant rate of a few times 10(42) erg s(-1) into the superbubble. A HST WFPC2 image decovers that NGC 4410a is seen almost face-on so that on ly the approaching outflow is visible. The HRI contours reveal an elongatio n of this outflow indicative for a faint X-ray ridge below the detection li mit (L-X less than or equal to 1.4x10(39) erg s(-1)) toward the neighbourin g galaxy NGC 4410b caused by its tidal interaction. NGC 4410b houses only a faint X-ray source (L-X less than or equal to 3.8 x 10(39) erg s(-1)).