J/MNRAS/462/3180 3FGL Blazar of Unknown Type classification (Chiaro+, 2016)
Blazar flaring patterns (B-FlaP) classifying blazar candidate of uncertain type
in the third Fermi-LAT catalogue by artificial neural networks.
Chiaro G., Salvetti D., La Mura G., Giroletti M., Thompson D.J.,
Bastieri D.
<Mon. Not. R. Astron. Soc., 462, 3180-3195 (2016)>
=2016MNRAS.462.3180C 2016MNRAS.462.3180C (SIMBAD/NED BibCode)
ADC_Keywords: Gamma rays ; QSOs ; BL Lac objects
Keywords: methods: statistical - galaxies: active -
BL Lacertae objects: general - gamma-rays: galaxies -
radio continuum: galaxies
Abstract:
The Fermi-Large Area Telescope (LAT) is currently the most important
facility for investigating the GeV γ-ray sky. With Fermi-LAT,
more than three thousand γ-ray sources have been discovered so
far. 1144 (∼40 per cent) of the sources are active galaxies of the
blazar class, and 573 (∼20 per cent) are listed as blazar candidate of
uncertain type (BCU), or sources without a conclusive classification.
We use the empirical cumulative distribution functions and the
artificial neural networks for a fast method of screening and
classification for BCUs based on data collected at γ-ray
energies only, when rigorous multiwavelength analysis is not
available. Based on our method, we classify 342 BCUs as BL Lacs and
154 as flat-spectrum radio quasars, while 77 objects remain uncertain.
Moreover, radio analysis and direct observations in ground-based
optical observatories are used as counterparts to the statistical
classifications to validate the method. This approach is of interest
because of the increasing number of unclassified sources in Fermi
catalogues and because blazars and in particular their subclass high
synchrotron peak objects are the main targets of atmospheric Cherenkov
telescopes.
Description:
We provide for each 3FGL BCU (Blazar of Unknown Type) the ANN
likelihood (L) to be a BL Lac or an FSRQ (flat-spectrum radio
quasars), and the predicted classification according to the defined
classification thresholds. We label the most promising HSP candidates,
splitting these objects into HC HSPs and VHC HSPs in agreement with
their likelihood to be an HSP-like source.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 66 573 Classification list of 3FGL BCUs
(Blazar of Unknown Type)
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See also:
J/ApJS/218/23 : Fermi LAT third source catalog (3FGL) (Acero+, 2015)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- 3FGL 3FGL name (JHHMM.m+DDMM)
14- 20 F7.3 deg GLAT Galactic latitude
22- 28 F7.3 deg GLON Galactic longitude
30- 37 E8.3 --- LBBL ANN likelihood to be classified as a BL Lac
39- 43 F5.3 --- LFSRQ ANN likelihood to be classified as a FSRQ
(flat-spectrum radio quasars)
45- 53 A9 --- Class Predicted classification (1)
55- 66 A12 --- HSPcand most promising HSP candidates (2)
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Note (1): BCU are classified as a BL Lac candidates if is greater than 0.566,
or FSRQ candidates if is greater than 0.770.
Note (2): most promising HSP candidates labelled as
very high C. or high C., where C. is for Confidence.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 15-Mar-2018