The Kinematics of Arp 295 in H-alpha Emission: an Interacting Galaxy with Highly Asymmetric Rotation
Abstract
Description
We investigate Arp 295, a pair of interacting spirals at z=0.023. We measure scalelengths 5.24 kpc for Arp 295a and 2.52 kpc for 295b. There is a much smaller Im galaxy associated with the larger spiral. Arp 295b is asymmetric with the disk more extended eastwards but with the brightest star-formation regions on the west side of the nucleus. The spectrum of Arp 295b shows strong emission lines with [OII]3727 prominent. We measure the total H-alpha line luminosities of Arp 295b and Arp 295c as 4.69x 10^{41} and 6.76x 10^{40} ergs/s, corresponding to star-formation rates 3.7 and 0.53 solar masses/year.
We map the kinematics of Arp 295b in H-alpha with the Manchester Echelle Spectrograph. The maximum disk rotation velocity is 252.6 km/s. The rotation curve of Arp 295b is very asymmetric. The east (approaching) side has a higher radial velocity than the west with the maximum difference 5 arcsec from the nucleus, where it is 88 km/s or a factor 1.675. The slowed rotation on the western side of the nucleus may have locally enhanced star-formation.
11 pages, 10 figures, revised version. Rev Mex Ast, in press. To appear vol 43, no. 1, April 2007
11 pages, 10 figures, revised version. Rev Mex Ast, in press. To appear vol 43, no. 1, April 2007