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

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.

Authors:
; ; ;  [1];  [2];
  1. Università degli Studi dell'Insubria, Via Valleggio 11, I-22100 Como (Italy)
  2. INAF-Osservatorio Astronomico di Padova, Vicolo dell Osservatorio 5, I-35122 Padova (Italy)
Publication Date:
OSTI Identifier:
22340061
Resource Type:
Journal Article
Journal Name:
Astronomical Journal (New York, N.Y. Online)
Additional Journal Information:
Journal Volume: 146; Journal Issue: 6; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1538-3881
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; BL LACERTAE OBJECTS; DETECTION; DISTANCE; EMISSION; GALAXIES; GAMMA RADIATION; RADIO TELESCOPES; RED SHIFT; SPECTROSCOPY

Citation Formats

Sandrinelli, A., Treves, A., Farina, E. P., Landoni, M., Falomo, R., Foschini, L., and Sbarufatti, B., E-mail: angela.sandrinelli@brera.inaf.it. Spectroscopy of optically selected BL Lac objects and their γ-ray emission. United States: N. p., 2013. Web. doi:10.1088/0004-6256/146/6/163.
Sandrinelli, A., Treves, A., Farina, E. P., Landoni, M., Falomo, R., Foschini, L., & Sbarufatti, B., E-mail: angela.sandrinelli@brera.inaf.it. Spectroscopy of optically selected BL Lac objects and their γ-ray emission. United States. https://doi.org/10.1088/0004-6256/146/6/163
Sandrinelli, A., Treves, A., Farina, E. P., Landoni, M., Falomo, R., Foschini, L., and Sbarufatti, B., E-mail: angela.sandrinelli@brera.inaf.it. 2013. "Spectroscopy of optically selected BL Lac objects and their γ-ray emission". United States. https://doi.org/10.1088/0004-6256/146/6/163.
@article{osti_22340061,
title = {Spectroscopy of optically selected BL Lac objects and their γ-ray emission},
author = {Sandrinelli, A. and Treves, A. and Farina, E. P. and Landoni, M. and Falomo, R. and Foschini, L. and Sbarufatti, B., E-mail: angela.sandrinelli@brera.inaf.it},
abstractNote = {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.},
doi = {10.1088/0004-6256/146/6/163},
url = {https://www.osti.gov/biblio/22340061}, journal = {Astronomical Journal (New York, N.Y. Online)},
issn = {1538-3881},
number = 6,
volume = 146,
place = {United States},
year = {Sun Dec 01 00:00:00 EST 2013},
month = {Sun Dec 01 00:00:00 EST 2013}
}