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Description
This database table contains a catalog of classifications for blazar candidates of uncertain type (BCU) detected by the Fermi Large Area Telescope gamma-ray instrument. These classifications have been determined by an Artificial Neural Network machine learning method. The aim of the authors' study was to develop an optimized version of this Artificial Neural Network machine learning method for classifying these blazar candidates. The final result of this study increased the classification performance by about 80% with respect to the method previously used for the classification of uncertain blazars in Chiaro et al. (<a href="https://ui.adsabs.harvard.edu/abs/2016MNRAS.462.3180C">2016MNRAS.462.3180C</a>, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/462/3180/">CDS Cat. J/MNRAS/462/3180</a>), leaving only 15 unclassified blazars out of 573 blazar candidates of uncertain type listed in the Fermi LAT 4-Year Source Catalog. Looking beyond the gamma-ray features of blazars, interesting information can be obtained from a multiwavelength study of the sources and particularly from X-ray and radio flux. In this study the authors tested the possibility to use those two parameters to improve the performance of the network. They did not consider any optical spectroscopy data because, when considering uncertain sources, optical spectra are very often not available or not sufficiently descriptive of the nature of the source. The gamma-ray flux was obtained by adding five time-integrated fluxes in five bands (0.1-0.3, 0.3-1, 1-3, 3-10, 10-100 GeV) from the <a href="/W3Browse/fermi/fermi3fgl.html">3FGL Catalog</a> (Acero et al. <a href="https://ui.adsabs.harvard.edu/abs/2015ApJS..218...23A">2015ApJS..218...23A</a>, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/218/23/">CDS Cat. J/ApJS/218/23</a>). Radio and X-ray data were obtained from the Fermi LAT 4-Year AGN Catalog 3LAC (Ackermann et al. <a href="https://ui.adsabs.harvard.edu/abs/2015ApJ...810...14A">2015ApJ...810...14A</a>, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/810/14/">CDS Cat. J/ApJ/810/14</a>). Radio fluxes used were measured at frequencies of 1.4 and 0.8 GHz; the X-ray fluxes were measured in the 0.1-2.4keV range. The complete list of 567 classified BCUs is presented in this table in which sources are ordered by increasing likelihood of a source being a BL Lac. This database table was ingested by the HEASARC in May 2023 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/490/4770">CDS Catalog J/MNRAS/490/4770</a> file table1.dat. This is a service provided by NASA HEASARC .
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