An HI line search for optically identified dwarf galaxy candidates in the M81 group
| dc.creator | van Driel, W. | |
| dc.creator | Kraan-Korteweg, R. C. | |
| dc.creator | Binggeli, B. | |
| dc.creator | Huchtmeier, W. K. | |
| dc.date | 1997-06-09 | |
| dc.date.accessioned | 2026-07-07T02:23:33Z | |
| dc.date.available | 2026-07-07T02:23:33Z | |
| dc.description | Sensitive 21cm HI line observations were performed for 23 dwarf members and possible members of the nearby M81 group of galaxies, including five objects of a clustering of extremely low-surface brightness objects of unknown nature. With the Nancay decimetric radio telescope the radial velocity range of -529 to 1826 km/s was searched to an rms noise of ~3-5 mJy. Only three objects were detected. However, their high radial velocities (between 600 and 1150 km/s) show them to lie behind the M81 group. These three objects, classified as dS0: (UGC 4998) and Im (Kar 1N and UGC 5658), have HI masses of 0.5, 2.0 and 2.5 10^8 Msun, for the assumed distance of 4 Mpc, and HI mass-to-blue light ratios of 0.05, 0.91 and 0.22 Msun/LBsun, respectively. Considering that half of the observed objects are classified as irregular dwarfs, hence expected to be relatively gas-rich, the resulting detection rate of about 1/3 is quite low. However, the mean redshift and velocity dispersion of the M81 group (<v> = 101 km/s, sigma=114 km/s) suggest that the HI emission of low velocity HI-rich members of the M81 group may still remain hidden within the strong Galactic HI emission (typically -150 < v < 115 km/s) or, for the 6 dwarf candidates in the immediate vicinity of M81, overshadowed by the very extended HI envelope encompassing M81, M82, NGC 3077, and NGC 2976 (-280 < v < 355 km/s). | |
| dc.description | Accepted for publication in A&ASS. 12 pages, LaTex, 2 encapsulated postscript figures, requires l-aa.sty and epsf.sty. Fig. 1 not avalaible in el. form | |
| dc.identifier | https://arxiv.org/abs/astro-ph/9706081 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/9706081 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/11289 | |
| dc.subject | Astrophysics | |
| dc.title | An HI line search for optically identified dwarf galaxy candidates in the M81 group | |
| dc.type | text |