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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Optical characterization of WISE selected blazar candidates

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de Menezes, Raniere [1, 2] ; Pena-Herazo, Harold A. [3, 1, 4, 5] ; Marchesini, Ezequiel J. [1, 4, 6, 7, 8] ; D'Abrusco, Raffaele [9] ; Masetti, Nicola [10, 8] ; Nemmen, Rodrigo [2] ; Massaro, Francesco [3, 1, 4, 11] ; Ricci, Federica [12, 13] ; Landoni, Marco [14] ; Paggi, Alessandro [3, 4] ; Smith, Howard A. [9]
Total Authors: 11
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[1] Univ Torino, Dipartimento Fis, Via Pietro Giuria 1, I-10125 Turin - Italy
[2] Univ Sao Paulo, Dept Astron, BR-05508090 Sao Paulo, SP - Brazil
[3] INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese - Italy
[4] INFN, Via Osservatorio 20, I-10125 Turin - Italy
[5] INAOE, Apartado Postal 51-216, Puebla 72000 - Mexico
[6] Univ Nacl La Plata, Fac Ciencias Astron & Geofis, B1900FWA, La Plata, Buenos Aires - Argentina
[7] UNLP, CONICET, CCT La Plata, Inst Astrofis Plata, B1900FWA, La Plata, Buenos Aires - Argentina
[8] INAF Osservatorio Astrofis & Sci Spazio, Via Gobetti 93-3, I-40129 Bologna - Italy
[9] Harvard & Smithsonian, Ctr Astrophys, 60 Garden St, Cambridge, MA 20138 - USA
[10] Univ Andres Bello, Dept Ciencias Fis, Fernandez Concha 700, Santiago - Chile
[11] CIFS, Via Pietro Giuria 1, I-10125 Turin - Italy
[12] Pontificia Univ Catolica Chile, Fac Fis, Inst Astrofis, Casilla 306, Santiago 22 - Chile
[13] Pontificia Univ Catolica Chile, Fac Fis, Ctr Astroingn, Casilla 306, Santiago 22 - Chile
[14] INAF Osservatorio Astron Brera, Via E Bianchi 46, Merate, LC - Italy
Total Affiliations: 14
Document type: Journal article
Source: Astronomy & Astrophysics; v. 630, SEP 23 2019.
Web of Science Citations: 0

Context. Over the last decade more than five thousand gamma-ray sources have been detected by the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope. Given the positional uncertainty of the telescope, nearly 30% of these sources remain without an obvious counterpart at lower energies. This has motivated the release of new catalogs of gamma-ray counterpart candidates and several follow up campaigns in the last decade. Aims. Recently, two new catalogs of blazar candidates were released. These are the improved and expanded version of the WISE Blazar-Like Radio-Loud Sources (WIBRaLS2) catalog and the Kernel Density Estimation selected candidate BL Lacs (KDE-BLLACS) catalog, both selecting blazar-like sources based on their infrared colors from the Wide-field Infrared Survey Explorer (WISE). In this work we characterize these two catalogs, clarifying the true nature of their sources based on their optical spectra from SDSS data release 15, thus testing their efficiency in selecting true blazars. Methods. We first selected all WIBRaLS2 and KDEBLLACS sources with available optical spectra in the footprint of Sloan Digital Sky Survey data release 15. We then analyzed these spectra to verify the nature of each selected candidate and to measure the fraction of the catalogs composed by spectroscopically confirmed blazars. Finally, we evaluated the impact of selection effects, especially those related to optical colors of WIBRaLS2/KDEBLLACS sources and their optical magnitude distributions. Results. We found that at least similar to 30% of each catalog is made up of confirmed blazars, with quasars being the major contaminants in the case of WIBRaLS2 (approximate to 58%) and normal galaxies in the case of KDEBLLACS (approximate to 38.2%). The spectral analysis also allowed us to identify the nature of 11 blazar candidates of uncertain type (BCUs) from the Fermi-LAT fourth Point Source Catalog (4FGL) and to find 25 new BL Lac objects. (AU)

FAPESP's process: 16/25484-9 - Optical observations of blazar candidates and unknown gamma-ray sources
Grantee:Raniere Maciel de Menezes
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 18/24801-6 - Multislit spectroscopy of unidentified gamma-ray sources
Grantee:Raniere Maciel de Menezes
Support type: Scholarships abroad - Research Internship - Doctorate
FAPESP's process: 17/01461-2 - The extreme universe: black holes and the Fermi telescope
Grantee:Rodrigo Nemmen da Silva
Support type: Research Grants - Young Investigators Grants