The merged group of galaxies RX J0419+0225
Abstract
RX J0419+0225 (z=0.0123) is a bright X-ray group of galaxies with its X-ray emission extending to 200 kpc in radius together with an X-ray luminosity of 1.3 × 1041 erg/s. Optically, however, this system has only a few member galaxies, mostly dominated by a central galaxy, NGC 1550. From our observation of RX J0419+0225 with ASCA, we determined the temperature and total mass to be 1.3 keV and 1.5 × 1013 M⊙, respectively. Therefore, the mass-to-light ratio (B band) of RX J0419+0225 comes to 400, comparable to those of galaxy clusters (Kawaharada et al. PASJ 55, 573, 2003). So far, several such 'dark group' candidates have been found and suspected to be galaxy merger remnants. To test the merger scenario, we observed RX J0419+0225 with XMM-Newton last year. Comparing the radial metal profile of RX J0419+0225 and that of NGC 5044 as a reference, we conclude that RX J0419+0225 has indeed formed through galaxy mergers.
- Publication:
-
35th COSPAR Scientific Assembly
- Pub Date:
- 2004
- Bibcode:
- 2004cosp...35.3767K