Spectral energy distributions of a large sample of BL Lacertae objects

By E. Nieppola, M. Tornikoski, E. Valtaoja. 2005

212 citations recorded by the source corpus.

We have collected a large amount of multifrequency data for the objects in the Metsahovi Radio Observatory BL Lacertae sample and computed their spectral energy distributions (SED) in the logν - log νF - representation. This is the first time the SEDs of BL Lacs have been studied with a sample of over 300 objects. The synchrotron components of the SEDs were fitted with a parabolic function to determine the synchr otron peak frequency,νpeak. We checked the dependence between luminosities at several frequency bands and synchrotron peak frequency to test the blazar sequence scenario, which states that the source luminosity depends on the location of the synchrotron peak. We also calculated broad band spectral indices and plotted them against each other andνpeak. The range ofνpeak in our study was considerably extended compared to previous studies. There were 22 objects for which logνpeak >19. The data shows that at 5 GHz, 37 GHz and 5500 A there is negative correlation between luminosity andνpeak, whereas in X-rays the correlation turns slightly positive. There is no significant correlation between source luminosi ty at syn- chrotron peak andνpeak. Several low radio luminosity-low energy peaked BL Lacs were found. The negative correlation between broad band spectral indices andνpeak is also significant, although there is substantial scatter. Therefore we find that neither αrx norαro can be used to determine the synchrotron peak of BL Lacs. On the grounds of our results we conclude that the blazar sequence scenario is not valid. In all our results the BL Lac population is continuous with no hint of the bimodality of the first BL Lac samples.

Subfields: Artificial Intelligence, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/df9e2b87ddd55f375b27f54570fedab1c75958b3

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In Artificial Intelligence

1. Anthony N. Lasenby

In Nuclear and High Energy Physics

1. P. Padovani
2. P. Giommi
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4. J. Rachen
5. J. Zensus
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Citations in the corpus

• Radio and millimeter continuum surveys and their astrophysical implications (2009, background): “The validity of the scenario has been questioned, however (e.g., Giommi et al. 1999; Padovani et al. 2003; Caccianiga & Marchã 2004; Antón & Browne 2005; Nieppola et al. 2006; Landt et al. 2006; Padovani 2007; Nieppola et al. 2008).”
• Simultaneous Planck, Swift, and Fermi observations of X-ray and γ-ray selected blazars (2011, background): “…between bolometric luminosity and νSpeakclaimed by Fossati et al. (1998) and Ghisellini et al. (1998) that remains a subject of lively debate (e.g., Giommi et al. 1999; Padovani et al. 2003; Caccianiga & Marchã 2004; Nieppola et al. 2006; Padovani 2007; Ghisellini & Tavecchio 2008).”
• Photopolarimetric Monitoring of Blazars in the Optical and Near-Infrared Bands with the Kanata Telescope. I. Correlations between Flux, Color, and Polarization (2011, methodology): “…from radio to γrays, Abdo et al. (2010a) propose a new classification for blazars (FSRQs and BL Lac objects): Low, intermedi1 http://glastweb.pg.infn.it/blazar/ remaining 11 objects by adopting the criteria defined in Abdo et al. (2010a) using νpeak estimated in Nieppola et al. (2006).”
• THE SPECTRAL ENERGY DISTRIBUTIONS OF FERMI BLAZARS (2016, methodology): “The spectral energy distributions (SEDs) are available for some blazars and studied in the literatures (see Sambruana et al. 1996; Zhang, et al. 2002; Nieppola et al. 2006, 2008; Abdo et al. 2010a).”
• A simplified view of blazars: clearing the fog around long‐standing selection effects (2011, background): “…of intense discussions since its first proposal by Fossati et al. (1998) and Ghisellini et al. (1998) (e.g., Giommi, Menna & Padovani 1999; Padovani et al. 2003; Caccianiga & Marchã 2004; Nieppola et al. 2006; Padovani 2007; Ghisellini & Tavecchio 2008; Nieppola et al. 2008; Giommi et al. 2011).”
• Astrophysical and cosmological information from large-scale submillimetre surveys of extragalactic sources (2007, methodology): “Also, Nieppola et al. (2006) did not find any correlation between luminosity and frequency of the synchrotron peak for their sample of 300 blazars.”
• The extragalactic background light and the gamma-ray opacity of the universe (2012, background): “They are referred to as low-frequency peaked BL Lacs (LBLs) if their synchrotron peak is at 1013 ≤ νpeak ≤ 10 14 Hz; as intermediate-frequency peaked BL Lacs (IBLs) if 1015 ≤ νpeak ≤ 10 16Hz; and as high-frequency peaked BL Lacs (HBLs) if νpeak ≥ 10 17Hz (Nieppola et al., 2006).”