Revista mexicana de astronomía y astrofísica
versão impressa ISSN 0185-1101
ROCHE, Nathan. The Kinematics of ARP 295 in Hα Emission: An Interacting Galaxy with Highly Asymmetric Rotation. Rev. mex. astron. astrofis [online]. 2007, vol.43, n.1, pp. 179-189. ISSN 0185-1101.
We investigate Arp 295, a pair of interacting spirals at z = 0.023, using optical spectroscopy, Ha imaging, and Ha velocity mapping with the Manchester Echelle Spectrograph. Scalelengths are rexp = 5.24 for Arp 295a and 2.52 kpc for 295b. A much smaller Im galaxy, Arp 295c, is associated with the larger spiral. Arp 295b is asymmetric with the disk more extended eastwards but with the brightest star-formation regions on its western side. The spectrum of Arp 295b shows strong emission lines with [OII] 3727 equivalent width 36Å. The total Hα luminosities of Arp 295b and Arp 295c are 4.69 x 1041 and 6.76 x 1040 ergs s -1, corresponding to star-formation rates 3.7 and 0.53 yr -1. For Arp 295b, we measure the maximum disk rotation velocity as 252.6 ± 9.9 km s -1 and find the rotation curve is very asymmetric. The east (approaching) side has a higher radial velocity than the west with the maximum difference (at r = 5 arcsec) of 88 km s -1, or a factor 1.675.
Palavras-chave : GALAXIES: INTERACTIONS.