J/A+A/579/A34 1WHSP: VHE γ-ray blazar candidates (Arsioli+, 2015)
1WHSP: an IR-based sample of ∼1,000 VHE gamma-ray blazar candidates.
Arsioli B., Fraga B., Giommi P., Padovani P., Marrese P.M.
<Astron. Astrophys. 579, A34 (2015)>
=2015A&A...579A..34A 2015A&A...579A..34A
ADC_Keywords: Gamma rays - QSOs
Keywords: galaxies: active - BL Lacertae objects: general -
radiation mechanisms: non-thermal - gamma rays: galaxies -
infrared: galaxies - virtual observatory tools
Abstract:
Blazars are the dominant type of extragalactic sources at microwave
and at γ-ray energies. In the most energetic part of the
electromagnetic spectrum (E≳100GeV) a high fraction of high
Galactic latitude sources are blazars of the high synchrotron peaked
(HSP) type, that is BL Lac objects with synchrotron power peaking in
the UV or in the X-ray band. Building new large samples of HSP blazars
is key to understand the properties of jets under extreme conditions,
and to study the demographics and the peculiar cosmological evolution
of these sources.
High synchrotron peaked blazars are remarkably rare, with only a few
hundreds of them expected to be above the sensitivity limits of
currently available surveys, some of which include hundreds of
millions of sources. To find these very uncommon objects, we have
devised a method that combines ALLWISE survey data with
multi-frequency selection criteria.
The sample was defined starting from a primary list of infrared
colour-colour selected sources from the ALLWISE all sky survey
database, and applying further restrictions on IR-radio and IR-X-ray
flux ratios. Using a polynomial fit to the multi-frequency data (radio
to X-ray), we estimated synchrotron peak frequencies and fluxes of
each object.
Description:
We assembled a sample including 992 sources, which is currently the
largest existing list of confirmed and candidates HSP blazars. All
objects are expected to radiate up to the highest γ-ray photon
energies. In fact, 299 of these are confirmed emitters of GeV
γ-ray photons (based on Fermi-LAT catalogues), and 36 have
already been detected in the TeV band. The majority of sources in the
sample are within reach of the upcoming Cherenkov Telescope Array
(CTA), and many may be detectable even by the current generation of
Cherenkov telescopes during flaring episodes. The sample includes 425
previously known blazars, 151 new identifications, and 416 HSP
candidates (mostly faint sources) for which no optical spectra is
available yet. The full 1WHSP catalogue is online at
http://www.asdc.asi.it/1whsp/, providing a direct link to the SED
building tool where multi-frequency data for each source can be easily
visualised.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 90 992 *1WHSP sample of High Synchrotron Peaked blazars
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Note on table2.dat: The full catalog is available at
http://www.asdc.asi.it/1whsp containing complementary information and a
direct link to the SED building tool where the multifrequency spectra for
each source can be quickly visualised.
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See also:
J/ApJS/188/405 : Fermi-LAT first source catalog (1FGL) (Abdo+, 2010)
J/ApJS/199/31 : Fermi LAT second source catalog (2FGL) (Nolan+, 2012)
J/A+A/495/691 : Blazar multifrequency catalogue Roma-BZCAT (Massaro+, 2009)
J/ApJ/764/135 : Spectroscopic redshifts of BL Lac objects (Shaw+, 2013)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- 1WHSP 1WHSPJ designation (HHMMSS.s+DDMMSS)
17 A1 --- Bz [y-] in BZcat (J/A+A/495/691)? (1)
19 A1 --- l_log(nup) [>] Limit flag on log(nup) (2)
20- 24 F5.2 [Hz] log(nup) [15/18.4] Peak frequency, νpeak
25 A1 --- u_log(nup) [*] Uncertainty flag on log(nup)
27 A1 --- l_log(fp) [>] Limit flag on log(fp)
28- 33 F6.2 [mW/m2] log(fp) [-13.1/-9.5] Peak flux in erg/cm2/s
[ν*fν(νpeak)]
34 A1 --- u_log(fp) [*] Uncertainty flag on log(fp)
36 A1 --- l_z [>] Limit flag on z
37- 42 F6.4 --- z [0.01/1.1]?=0 Redshift (3)
44- 48 F5.2 --- rmag [14/20.3]? r magnitude used for redshift (3)
49 A1 --- r_z [bcdefg] References of z (3)
50 A1 --- u_z [*] Uncertainty flag on z
51- 67 A17 --- Fermi-LAT γ-ray counterpart in the FERMI catalogs
69- 71 F3.1 --- Gamma [1.1/2.7]?=- Photon index Γ measured
for the energy band 0.1GeV<E<100GeV from
FERMI catalogs (1FGL, 2FGL, or 3FGL)
73- 76 F4.2 --- e_Gamma [0.01/0.5]? rms uncertainty on Gamma
78 I1 --- Type [0/5] Source type (4)
83 A1 --- TeV [y-] in TeVCat ? (5)
86- 90 F5.2 --- FOM [0.02/57.5] Figure Of Merit: likelihood of
detection in the TeV band (see section 4.5)
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Note (1): BZcat, Massaro et al., 2011, http://www.asdc.asi.it/bzcat.
Note (2): The lower limit on log(νpeak) is due to lack of data in higher
energies.
Note (3): Upper/Lower limits on the redshift are taken from
a = Shaw et al., 2013ApJ...764..135S 2013ApJ...764..135S, Cat. J/ApJ/764/135
b = Pita et al., 2014A&A...565A..12P 2014A&A...565A..12P
c = Furniss et al., 2013ApJ...768L..31F 2013ApJ...768L..31F
d = Danforth et al., 2010ApJ...720..976D 2010ApJ...720..976D
e = Shaw et al., 2013AJ....146..127S 2013AJ....146..127S
f = Masetti et al., 2013A&A...559A..58M 2013A&A...559A..58M
g = Sbarufatti et al., 2005AJ....129..559S 2005AJ....129..559S
(blank) = calculated by us (see Section 3.2) using the observed red magnitude
mr that is given in rmag column.
Note (4): indicates if the source is a spectroscopically confirmed HSP
as follows:
0 = previously known blazar
5 = newly identified blazar
1 = a candidate HSP (High Synchrotron Peaked )
2 = a complementary source from the Sedentary survey
3 = if it is classified as extended by WISE (Cutri et al., 2012, Cat. II/311)
4 = complementary source from TeVCat
Note (5): TeVCat, http://tevcat.uchicago.edu/
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Acknowledgements:
Bruno Arsioli, bruno.arsioli(at)asdc.asi.it
(End) Patricia Vannier [CDS] 08-Apr-2015