J/ApJ/841/113 Roma-BZCAT synchroton peak & Compton dominance (Mao+, 2017)
An investigation of blazars without redshifts: not a missing population at high redshift. Mao P., Urry C.M. <Astrophys. J., 841, 113 (2017)> =2017ApJ...841..113M
ADC_Keywords: BL Lac objects ; QSOs Keywords: accretion, accretion disks; astronomical databases: miscellaneous; BL Lacertae objects: general; quasars: general Abstract: We investigate a sample of 622 blazars with measured fluxes at 12 wavebands across the radio-to-gamma-ray spectrum but without spectroscopic or photometric redshifts. This sample includes hundreds of sources with newly analyzed X-ray spectra reported here. From the synchrotron peak frequencies, estimated by fitting the broadband spectral energy distributions (SEDs), we find that the fraction of high-synchrotron-peaked blazars in these 622 sources is roughly the same as in larger samples of blazars that do have redshifts. We characterize the no-redshift blazars using their infrared colors, which lie in the distinct locus called the WISE blazar strip, then estimate their redshifts using a KNN regression based on the redshifts of the closest blazars in the WISE color-color plot. Finally, using randomly drawn values from plausible redshift distributions, we simulate the SEDs of these blazars and compare them to known blazar SEDs. Based on all these considerations, we conclude that blazars without redshift estimates are unlikely to be high-luminosity, high- synchrotron-peaked objects, which had been suggested in order to explain the "blazar sequence"-an observed trend of SED shape with luminosity-as a selection effect. Instead, the observed properties of no-redshift blazars are compatible with a causal connection between jet power and electron cooling, i.e., a true blazar sequence. Description: We base our blazar sample on data from the Multi-wavelength Catalog of blazars, Roma-BZCAT1 v5.0 (see Massaro+ 2009, J/A+A/495/691). The details of the sample selection from Roma-BZCAT, as well as the association of sources across multiple wavelengths, can be found in Paper I (Mao+, 2016, J/ApJS/224/26). We define as Sample I the 2220 blazars in that paper, all of which have redshifts and radio fluxes. In this paper, we focus on the 622 spectroscopically confirmed BL Lacs that do not have redshift estimates, which we call Sample II. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table3.dat 138 2943 *Synchrotron peak and Compton dominance for samples I and II
Note on table3.dat: See the "Description" section above for the sample definitions.
See also: VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998) VIII/59 : the FIRST Survey, version 1999Jul (White+ 1999) V/139 : The SDSS Photometric Catalog, DR9 (Adelman-McCarthy+, 2012) V/147 : The SDSS Photometric Catalog, DR12 (Alam+, 2015) J/MNRAS/323/757 : Deep X-Ray Radio Blazar Survey (DXRBS). II. (Landt+, 2001) J/A+A/445/441 : SED of BL Lacertae objects (Nieppola+, 2006) J/A+A/488/867 : Synchrotron peak frequency of 135 AGN (Nieppola+, 2008) J/A+A/495/691 : Multifrequency catalog of blazars Roma-BZCAT (Massaro+, 2009) J/ApJ/748/68 : WISE IR colors of gamma-ray blazars (D'Abrusco+, 2012) J/ApJ/772/26 : AGN with WISE. II. The NDWFS Bootes field (Assef+, 2013) J/ApJS/206/12 : Blazars with γ-ray counterparts. I. (D'Abrusco+, 2013) J/ApJS/215/14 : WISE γ-ray blazar radio candidates (D'Abrusco+, 2014) J/ApJS/218/23 : Fermi LAT third source catalog (3FGL) (Acero+, 2015) J/ApJ/810/14 : Third catalog of LAT-detected AGNs (3LAC) (Ackermann+, 2015) J/ApJS/224/26 : SEDs of Roma BZCAT blazars (Mao+, 2016) http://www.sdss3.org/ : SDSS-III home page http://www.asdc.asi.it/bzcat/ : Roma BZCAT - 5th edition home page http://fermi.gsfc.nasa.gov/ssc/data/access/lat/4yr_catalog/ : 3FGL home page Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 13 A13 --- BZCAT BZCAT identifier (1) 15- 19 F5.2 [Hz] logPk [12/18]? Log observed frame synchrotron peak frequency (2) 21- 40 A20 --- n_logPk Note on logPk (3) 42- 46 F5.2 [Hz] logPkr [12/18]? Log rest frame synchrotron peak frequency (2) 48- 78 A31 --- n_logPkr Note on logPkr (3) 80- 84 F5.2 [Hz] logPkC [19/25]? Log observed frame Compton peak frequency (2) 86-102 A17 --- n_logPkC Note on logPkC (4) 104-108 F5.2 [Hz] logPkCr [18/25]? Log rest frame Compton peak frequency (2) 110-126 A17 --- n_logPkCr Note on logPkCr (4) 128-132 F5.2 --- AC [-1.5/2.1]? Compton Dominance in observed frame (fpeak,C/fpeak,s) 134-138 F5.2 --- ACr [-1.1/2.6]? Compton Dominance corrected to rest frame (Lpeak,C/Lpeak,s; only for Sample I)
Note (1): A total of 652 objects (362 Sample I FSRQ, 62 Sample I BL Lac, 228 Sample II BL Lac) had enough data fitted with a physical peak in fluxes, and 339 objects from Sample I (294 FSRQ, 45 BL Lac) had good fits in luminosities. Please note that BZBJ1701+3954 identifier is ambiguous and can be two different sources; note added by CDS. Note (2): νLν, only for Sample I. Note (3): Peaks are considered unphysical if the fitted peak frequency falls outside the 12 - 18 range. Note (4): Peaks are considered unphysical if the fitted peak frequency falls outside the 19 - 26 range.
Nomenclature note: Objects are <[MGL2015] 5BZB JHHMM+DDMMa> in Simbad. History: From electronic version of the journal References: Mao et al. Paper I. 2016ApJS..224...26M Cat. J/ApJS/224/26
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 23-Jan-2018
|The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line|