OPTICAL SPECTROSCOPIC OBSERVATIONS OF gamma-RAY BLAZAR CANDIDATES. I. PRELIMINARY RESULTS
Paggi A, Milisavljevic D, Masetti N, Jimenez-Bailon E, Chavushyan V, D'Abrusco R, Massaro F, Giroletti M, Smith HA, Margutti R, Tosti G, Martinez-Galarza JR, Oti-Floranes H, Landoni M, Grindlay JE, Funk S (2014)
Publication Status: Published
Publication Type: Journal article
Publication year: 2014
Journal
Publisher: American Astronomical Society
Book Volume: 147
DOI: 10.1088/0004-6256/147/5/112
Abstract
A significant fraction (similar to 30%) of the gamma-ray sources listed in the second Fermi/LAT (2FGL) catalog is still of unknown origin, being not yet associated with counterparts at lower energies. Using the available information at lower energies and optical spectroscopy on the selected counterparts of these gamma-ray objects, we can pinpoint their exact nature. Here, we present a pilot project pointing to assess the effectiveness of the several classification methods developed to select gamma-ray blazar candidates. To this end, we report optical spectroscopic observations of a sample of five gamma-ray blazar candidates selected on the basis of their infrared Wide-field Infrared Survey Explorer (WISE) colors or of their low-frequency radio properties. Blazars come in two main classes, BL Lac objects and FSRQs, showing similar optical spectra except for the stronger emission lines of the latter. For three of our sources, the almost featureless optical spectra obtained confirm their BL Lac nature, while for the source WISEJ022051.24+250927.6 we observe emission lines with equivalent width EW similar to 31 angstrom, identifying it as a FSRQ with z = 0.48. The source WISEJ064459.38+603131.7, although not featuring a clear radio counterpart, shows a blazar-like spectrum with weak emission lines with EW similar to 7 angstrom, yielding a redshift estimate of z = 0.36. In addition, we report optical spectroscopic observations of four WISE sources associated with known gamma-ray blazars without a firm classification or redshift estimate. For the latter sources, we confirm a BL Lac classification, with a tentative redshift estimate for the source WISEJ100800.81+062121.2 of z = 0.65.
Authors with CRIS profile
Involved external institutions
Harvard University
United States (USA) (US)
National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF)
Italy (IT)
National Autonomous University of Mexico / Universidad Nacional Autónoma de México (UNAM)
Mexico (MX)
Stanford National Accelerator Laboratory (SLAC)
United States (USA) (US)
Università degli Studi di Perugia
Italy (IT)
United States (USA) (US)
National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF)
Italy (IT)
National Autonomous University of Mexico / Universidad Nacional Autónoma de México (UNAM)
Mexico (MX)
Stanford National Accelerator Laboratory (SLAC)
United States (USA) (US)
Università degli Studi di Perugia
Italy (IT)
How to cite
APA:
Paggi, A., Milisavljevic, D., Masetti, N., Jimenez-Bailon, E., Chavushyan, V., D'Abrusco, R.,... Funk, S. (2014). OPTICAL SPECTROSCOPIC OBSERVATIONS OF gamma-RAY BLAZAR CANDIDATES. I. PRELIMINARY RESULTS. Astronomical Journal, 147. https://dx.doi.org/10.1088/0004-6256/147/5/112
MLA:
Paggi, A., et al. "OPTICAL SPECTROSCOPIC OBSERVATIONS OF gamma-RAY BLAZAR CANDIDATES. I. PRELIMINARY RESULTS." Astronomical Journal 147 (2014).
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