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

Autor(en)

D Tschöke, Gerhard Hensler, N Junkes

Abstrakt

We present X-ray observations of the interacting pair of galaxies NGC 4410a/b with the ROSAT HRI and PSPC. The ROS AT HRI images reveal a point-like source corresponding to NGC 4410a and an X-ray halo, extending 10? from the nucleus toward the southeast. The halo emission accounts for ~1/3 (LX = 1.3×1041 erg s-1 in the 0.1-2.4 keV ROS AT band) of the total X-ray emission detected from NGC 4410a. The spectrum of the total X-ray emission from NGC 4410a can be fitted at best with a two-component emission model, combining a Raymond-Smith spectrum with T = 107 K and a power-law spectrum (? = 2.2). The fraction of the thermal component to the total flux within this model is 35%, supporting the results of the HRI observation. The total unresolved X-ray luminosity detected with the PSPC amounts to 4×1041 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 expansion time of ~8 Myr. The central source injects mechanical energy at a constant rate of a few times 1042 erg s-1 into the superbubble. A HST WFPC2 image decovers that NGC 4410a is seen almost face-on so that only the approaching outflow is visible. The HRI contours reveal an elongation of this outflow indicative for a faint X-ray ridge below the detection limit (LX = 1.4×1039 erg s-1) toward the neighbouring galaxy NGC 441 Ob caused by its tidal interaction. NGC 4410b houses only a faint X-ray source (LX = 3.8×1039 erg s-1).

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

Christian-Albrechts-Universität zu Kiel, Max-Planck-Institut für Radioastronomie

Journal

Astronomy & Astrophysics

Band

343

Seiten

373-384

Anzahl der Seiten

12

ISSN

0004-6361

Publikationsdatum

1999

Peer-reviewed

Ja

ÖFOS 2012

103003 Astronomie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/rosat-xray-observations-of-the-interacting-pair-of-galaxies-ngc-4410-evidence-for-a-central-starburst(ddb0b531-0b3a-4bf7-bd88-10089f0b85f5).html