A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
37 GHz observations of a large sample of BL lacertae objects
Tekijät: Nieppola E, Tornikoski M, Lahteenmaki A, Valtaoja E, Hakala T, Hovatta T, Kotiranta M, Nummila S, Ojala T, Parviainen M, Ranta M, Saloranta PM, Torniainen I, Troller M
Kustantaja: UNIV CHICAGO PRESS
Julkaisuvuosi: 2007
Lehti:: Bulletin of the American Astronomical Society
Tietokannassa oleva lehden nimi: ASTRONOMICAL JOURNAL
Lehden akronyymi: ASTRON J
Vuosikerta: 133
Numero: 5
Aloitussivu: 1947
Lopetussivu: 1953
Sivujen määrä: 7
ISSN: 0004-6256
DOI: https://doi.org/10.1086/512609
Tiivistelmä
We present 37 GHz data obtained at Metsahovi Radio Observatory from 2001 December to 2005 April for a large sample of BL Lacertae objects. We also report the mean variability indices and radio spectral indices in frequency intervals 5-37 and 37-90 GHz. Approximately 34% of the sample was detected at 37 GHz, 136 BL Lacertae objects in all. A large majority of the detected sources were low-energy BL Lac objects. The variability index values of the sample were diverse, the mean fractional variability of the sample being Delta S-2 = 0.31. The spectral indices also varied widely, but the average radio spectrum of the sample sources is flat. Our observations show that many of the high-energy BL Lac objects, which are usually considered radio-quiet, can at times be detected at 37 GHz.
We present 37 GHz data obtained at Metsahovi Radio Observatory from 2001 December to 2005 April for a large sample of BL Lacertae objects. We also report the mean variability indices and radio spectral indices in frequency intervals 5-37 and 37-90 GHz. Approximately 34% of the sample was detected at 37 GHz, 136 BL Lacertae objects in all. A large majority of the detected sources were low-energy BL Lac objects. The variability index values of the sample were diverse, the mean fractional variability of the sample being Delta S-2 = 0.31. The spectral indices also varied widely, but the average radio spectrum of the sample sources is flat. Our observations show that many of the high-energy BL Lac objects, which are usually considered radio-quiet, can at times be detected at 37 GHz.
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