Please use this identifier to cite or link to this item:
http://hdl.handle.net/20.500.12386/23761
Title: | Looking for the least luminous BL Lacertae objects | Authors: | CAPETTI, Alessandro RAITERI, Claudia Maria |
Issue Date: | 2015 | Journal: | ASTRONOMY & ASTROPHYSICS | Number: | 580 | First Page: | A73 | Abstract: | Among active galactic nuclei, BL Lac objects show extreme properties that have been interpreted as the effect of relativistic beaming on the emission from a plasma jet oriented close to the line of sight. The Doppler amplification of the jet emission makes them ideal targets for studying jet physics. In particular, low-power BL Lacs (LPBL) are very interesting because they probe the jet formation and emission processes at the lowest levels of accretion. However, they are difficult to identify since their emission is swamped by the radiation from the host galaxy in most observing bands. In this paper we propose a new LPBL selection method based on the mid-infrared emission, in addition to the traditional optical indices. We considered the radio-selected sample of Best & Heckman (2012, MNRAS, 421, 1569) and cross-matched it with the WISE all-sky survey. In a new diagnostic plane including the W2-W3 color and the Dn(4000) index, LPBL are located in a region scarcely populated by other sources. By filtering objects with small emission line equivalent width, we isolated 36 LPBL candidates up to redshift 0.15. Their radio luminosity at 1.4 GHz spans the range log L<SUB>r</SUB> = 39.2-41.5 [erg s<SUP>-1</SUP>]. Considering the completeness of our sample, we analyzed the BL Lac luminosity function (RLF), finding a dramatic paucity of LPBL with respect to the extrapolation of the RLF toward low power. This requires a break in the RLF located at log L<SUB>r</SUB> ~ 40.6 [erg s<SUP>-1</SUP>]. The consequent peak in the BL Lacs number density is possibly the manifestation of a minimum power required to launch a relativistic jet. | Acknowledgments: | We are deeply indebted to the anonymous referee for the careful reading of the manuscript and for the many useful and insightful suggestions. This research made use of the NASA/ IPAC Infrared Science Archive and Extragalactic Database (NED), which are operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the US Department of Energy Office of Science. The SDSS-III web site is http://www.sdss3.org/ . SDSS-III is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III Collaboration, including the University of Arizona, the Brazilian Participation Group, Brookhaven National Laboratory, University of Cambridge, Carnegie Mellon University, University of Florida, the French Participation Group, the German Participation Group, Harvard University, the Instituto de Astrofisica de Canarias, the Michigan State/Notre Dame/JINA Participation Group, Johns Hopkins University, Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, Max Planck Institute for Extraterrestrial Physics, New Mexico State University, New York University, Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, the Spanish Participation Group, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington, and Yale University. 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. Part of this work is based on archival data, software or online services provided by the ASI Science Data Center (ASDC). | URI: | http://hdl.handle.net/20.500.12386/23761 | URL: | https://www.aanda.org/articles/aa/abs/2015/08/aa25890-15/aa25890-15.html | ISSN: | 0004-6361 | DOI: | 10.1051/0004-6361/201525890 | Bibcode ADS: | 2015A&A...580A..73C | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
aa25890-15.pdf | [pdf editoriale] | 8.69 MB | Adobe PDF | View/Open |
Page view(s)
53
checked on Aug 5, 2024
Download(s)
15
checked on Aug 5, 2024
Google ScholarTM
Check
Altmetric
Altmetric
Items in DSpace are published in Open Access, unless otherwise indicated.