Spectroscopy of optically selected BL Lac objects and their γ-ray emission

A. Sandrinelli, A. Treves, R. Falomo, E. P. Farina, L. Foschini, M. Landoni, B. Sbarufatti

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

We present Very Large Telescope optical spectroscopy of nine BL Lac objects of unknown redshift belonging to the list of optically selected radio-loud BL Lac candidates. We explore their spectroscopic properties and possible link with gamma-ray emission. From the new observations we determine the redshifts of four objects from faint emission lines or from absorption features of their host galaxies. In three cases we find narrow intervening absorptions from which a lower limit to the redshift is inferred. For the remaining two featureless sources, lower limits to the redshift are deduced from the absence of spectral lines. A search for γ counterpart emission shows that six out of the nine candidates are Fermi γ-ray emitters and we find two new detections. Our analysis suggests that most of the BL Lac objects still lacking redshift information are most likely located at high redshifts.

Original languageEnglish (US)
Article number163
JournalAstronomical Journal
Volume146
Issue number6
DOIs
StatePublished - Dec 1 2013

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rays
spectroscopy
lists
line spectra
emitters
gamma rays
telescopes
radio
galaxies
detection
analysis

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Sandrinelli, A., Treves, A., Falomo, R., Farina, E. P., Foschini, L., Landoni, M., & Sbarufatti, B. (2013). Spectroscopy of optically selected BL Lac objects and their γ-ray emission. Astronomical Journal, 146(6), [163]. https://doi.org/10.1088/0004-6256/146/6/163
Sandrinelli, A. ; Treves, A. ; Falomo, R. ; Farina, E. P. ; Foschini, L. ; Landoni, M. ; Sbarufatti, B. / Spectroscopy of optically selected BL Lac objects and their γ-ray emission. In: Astronomical Journal. 2013 ; Vol. 146, No. 6.
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Sandrinelli, A, Treves, A, Falomo, R, Farina, EP, Foschini, L, Landoni, M & Sbarufatti, B 2013, 'Spectroscopy of optically selected BL Lac objects and their γ-ray emission', Astronomical Journal, vol. 146, no. 6, 163. https://doi.org/10.1088/0004-6256/146/6/163

Spectroscopy of optically selected BL Lac objects and their γ-ray emission. / Sandrinelli, A.; Treves, A.; Falomo, R.; Farina, E. P.; Foschini, L.; Landoni, M.; Sbarufatti, B.

In: Astronomical Journal, Vol. 146, No. 6, 163, 01.12.2013.

Research output: Contribution to journalArticle

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Sandrinelli A, Treves A, Falomo R, Farina EP, Foschini L, Landoni M et al. Spectroscopy of optically selected BL Lac objects and their γ-ray emission. Astronomical Journal. 2013 Dec 1;146(6). 163. https://doi.org/10.1088/0004-6256/146/6/163