Astronomy and Astrophysics – Astrophysics
Scientific paper
2004-03-04
Astron.Astrophys. 419 (2004) 459-467
Astronomy and Astrophysics
Astrophysics
9 pages, 5 figures, to be published in Astronomy and Astrophysics
Scientific paper
10.1051/0004-6361:20034320
We present simultaneous multifrequency radio observations for a complete subsample of 26 XBLs from the Einstein Extended Medium-Sensitivity Survey, obtained with the Very Large Array (VLA). Spectra are computed using fluxes at 20, 6 and 3.6 cm. Unlike many radio selected samples, the EMSS did not impose any criterion on the radio spectrum to identify BL Lac objects. It is therefore possible to investigate the intrinsic radio spectral slope distribution and to determine the effect produced by this selection criterion. We find that 15% of the observed objects do not meet the flat-spectrum criterion imposed on some other BL Lac samples. A dataset that includes non-simultaneous data (that are also taken with different VLA configurations) shows an even higher percentage of steep spectrum sources. This effect can be ascribed to a larger fraction of extended flux detected with the more compact VLA configuration.Possible biases introduced by the flat--radio-spectrum criterion in the radio-selected BL Lac samples cannot explain the discrepancies observed in the evolutionary properties of Radio and X-ray selected samples of BL Lacs.
Cavallotti Francesca
Rector Travis
Stocke John T.
Wolter Anna
No associations
LandOfFree
Radio spectra of a sample of X-ray selected BL Lacs 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 Radio spectra of a sample of X-ray selected BL Lacs, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Radio spectra of a sample of X-ray selected BL Lacs will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-590470