Astronomy and Astrophysics – Astrophysics
Scientific paper
2001-11-19
Mon.Not.Roy.Astron.Soc. 330 (2002) 307
Astronomy and Astrophysics
Astrophysics
20 pages, latex, 16 figures, accepted for publication in MNRAS
Scientific paper
10.1046/j.1365-8711.2002.05051.x
We investigate the nature of the faintest radio sources detected in 3 VLA surveys, to faint limits 8 microJy at 8.5 GHz. Using the Keck Low Resolution Imaging Spectrograph in BRI and the Near Infra Red Camera in K, we image 51 radio sources, and identify probable optical counterparts for 50. With LRIS spectroscopy, we successfully acquire new redshifts for 17 sources, and 9 have redshifts from previous data. Of this sample of 26, about 60 per cent are disk galaxies with high radio to optical ratios, indicating ongoing or very recent starbursts, at redshifts z=0-1. Others are normal, non-interacting galaxies at z<0.4, QSOs and radioluminous giant ellipticals (obscured AGN?). All of the 14 non-QSO galaxies with spectra show emission lines, but with luminosities corresponding to star-formation rates about an order of magnitude lower than estimated from the high radio luminosities (dust extinction?). Three have strong H-delta absorption (`e+a galaxies'). The Keck spectra also provide approximate emission line widths and rotation curves. Most (12/14) have kinematics implying large dynamical masses, and moderate excitation ratios consistent with L* spirals. The other two, which have sub-L* optical luminosities, appear to be low-mass galaxies with much higher excitations and may be more similar to HII galaxies.
Koo David
Lowenthal James
Roche Nathan
No associations
LandOfFree
Keck Spectroscopy and Imaging of Faint Galaxies Identified as MicroJansky Radio Sources does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Keck Spectroscopy and Imaging of Faint Galaxies Identified as MicroJansky Radio Sources, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Keck Spectroscopy and Imaging of Faint Galaxies Identified as MicroJansky Radio Sources will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-274641