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|Title:||Optical spectroscopic observations of γ-ray blazar candidates. II. The 2013 KPNO campaign in the northern hemisphere||Authors:||Massaro, F.
Smith, H. A.
|Issue Date:||2015||Journal:||ASTRONOMY & ASTROPHYSICS||Number:||575||First Page:||1||Abstract:||Context. We recently started a systematic search of low-energy counterparts of the unidentified γ-ray sources (UGSs) listed in the Fermi-Large Area Telescope (LAT) First Source Catalog (1FGL) and the Fermi-LAT 2-Year Source Catalog (2FGL). <BR /> Aims: The main goal of our investigation is to find active galaxies belonging to the blazar class that lie within the positional uncertainty region of the UGSs and thus could be their potential low-energy counterparts. <BR /> Methods: To achieve our aims, we first adopted several procedures based on the peculiar observational properties of blazars in the radio and in the IR. Then we carried out a follow-up spectroscopic campaign in the optical band to verify the nature of the candidates selected as potential counterparts of the UGSs. Here we present the results of the observations carried out in 2013 in the northern hemisphere at Kitt Peak National Observatory (KPNO). Optical spectroscopy is crucial to confirm the nature of the sources and can be used to estimate their redshifts; it will also allow us to test the robustness of our methods when the whole campaign is completed. <BR /> Results: Here we present the optical spectroscopic observations of 39 sources. Within our sample we found that 6 sources are blazars, candidates to be low-energy counterparts of the UGSs listed in the 2FGL. We confirm that an additional 8 sources, previously classified as active galaxies of uncertain type and associated in the 2FGL, are also all BL Lac objects. Moreover, we also present 20 new spectra for known blazars listed in the Multi-frequency Catalogue of Blazars as having an uncertain redshift and/or being classified as BL Lac candidates. <BR /> Conclusions: We conclude that our methods for selecting γ-ray blazar candidates allows us to discover new blazars and increase the list of potential low-energy counterparts for the Fermi UGSs. <P />||Acknowledgments:||We thank the referee Y. Tanaka for useful comments that led to improvements in the paper. We are grateful to D. Hammer for her help to schedule, prepare, and perform the KPNO observations. This investigation is supported by the NASA grants NNX12AO97G and NNX13AP20G. H. A. Smith acknowledges partial support from NASA/JPL grant RSA 1369566. The work by G. Tosti is supported by the ASI/INAF contract I/005/12/0. part of this work is based on archival data, software or on-line services provided by the ASI Science Data Center. This research has made use of data obtained from the high-energy Astrophysics Science Archive Research Center (HEASARC) provided by NASA’s Goddard Space Flight Center; the SIMBAD database operated at CDS, Strasbourg, France; the NASA/IPAC Extragalactic Database (NED) operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Part of this work is based on the NVSS (NRAO VLA Sky Survey): The National Radio Astronomy Observatory is operated by Associated Universities, Inc., under contract with the National Science Foundation and on the VLA low-frequency Sky Survey (VLSS). The Molonglo Observatory site manager, Duncan Campbell-Wilson, and the staff, Jeff Webb, Michael White and John Barry, are responsible for the smooth operation of Molonglo Observatory Synthesis Telescope (MOST) and the day-to-day observing programme of SUMSS. The SUMSS survey is dedicated to Michael Large whose expertise and vision made the project possible. The MOST is operated by the School of Physics with the support of the Australian Research Council and the Science Foundation for Physics within the University of Sydney. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This research has made use of the USNOFS Image and Catalogue Archive operated by the United States Naval Observatory, Flagstaff Station ( http://www.nofs.navy.mil/data/fchpix/ ). Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the US Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Web Site is http://www.sdss.org/ . The SDSS is managed by the Astrophysical Research Consortium for the Participating Institutions. The WENSS project was a collaboration between the Netherlands Foundation for Research in Astronomy and the Leiden Observatory. We acknowledge the WENSS team consisted of Ger de Bruyn, Yuan Tang, Roeland Rengelink, GeorgeMiley, Huub Rottgering, Malcolm Bremer, Martin Bremer, Wim Brouw, Ernst Raimond and David Fullagar for the extensive work aimed at producing the WENSS catalog. TOPCAT 8 ( Taylor, 2005 ) for the preparation and manipulation of the tabular data and the images. The Aladin Java applet 9 was used to create the finding charts reported in this paper ( Bonnarell et al., 2000 ). It can be started from the CDS (Strasbourg – France), from the CFA (Harvard – USA), from the ADAC (Tokyo – Japan), from the IUCAA (Pune – India), from the UKADC (Cambridge – UK), or from the CADC (Victoria – Canada).||URI:||http://hdl.handle.net/20.500.12386/23168||URL:||https://www.aanda.org/articles/aa/full_html/2015/03/aa25119-14/aa25119-14.html||ISSN:||0004-6361||DOI:||10.1051/0004-6361/201425119||Bibcode ADS:||2015A&A...575A.124M||Fulltext:||open|
|Appears in Collections:||1.01 Articoli in rivista|
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