J/ApJ/867/131 Blazar candidates behind the Magellanic Clouds (Zywucka+, 2018)
Identification of blazar candidates behind Small and Large Magellanic Clouds.
Zywucka N., Goyal A., Jamrozy M., Stawarz L., Ostrowski M., Kozlowski S.,
Udalski A.
<Astrophys. J., 867, 131 (2018)>
=2018ApJ...867..131Z 2018ApJ...867..131Z
ADC_Keywords: BL Lac objects; Active gal. nuclei; QSOs; Magellanic Clouds;
Photometry, VRI; Radio lines; Redshifts; Surveys
Keywords: BL Lacertae objects: general ; galaxies: active ; Magellanic Clouds
Abstract:
We report the identification of blazar candidates behind the
Magellanic Clouds. The objects were selected from the Magellanic
Quasars Survey (MQS), which targeted the entire Large Magellanic Cloud
(LMC) and 70% of the Small Magellanic Cloud (SMC). Among the 758 MQS
quasars and 898 of the unidentified (featureless spectra) objects, we
identified a sample of 44 blazar candidates, including 27
flat-spectrum radio quasars and 17 BL Lacertae objects, respectively.
All the blazar candidates from our sample were identified with respect
to their radio, optical, and midinfrared properties. The newly
selected blazar candidates possess the long-term, multicolor
photometric data from the Optical Gravitational Lensing Experiment,
multicolor midinfrared observations, and archival radio data for one
frequency at least. In addition, for nine of them, the radio
polarization data are available. With such data, these objects can be
used to study the physics behind the blazar variability detected in
the optical and midinfrared bands, as a tool to investigate magnetic
field geometry of the LMC and SMC, and as an exemplary sample of
point-like sources most likely detectable in the γ-ray range
with the newly emerging Cherenkov Telescope Array.
Description:
In the present study, we report the identification of blazar
candidates behind the Large Magellanic Cloud (LMC) and Small
Magellanic Cloud (SMC), which are selected from the catalog of the
Magellanic Quasar Survey (MQS; Kozlowski+ 2013, J/ApJ/775/92) and a
"featureless spectra" (FS) objects list (See Section 2).
Both the LMC and SMC regions were observed with the Wise Infrared
Survey Explorer (WISE) satellite (angular resolutions of 6.1" 6.4",
6.5", and 12.0", in 3.4um, 4.6um, 12um and 22um, respectively); and
with the Spitzer IRAC and MIPS instruments as part of the program
Surveying the Agents of a Galaxys Evolution (SAGE; Meixner+, 2006,
J/AJ/132/2268 and Gordon+ 2011AJ....142..102G 2011AJ....142..102G). The angular resolution
is 1.7", 1.7", 1.9", and 2.0" in the IRAC bands, centered at 3.6, 4.5,
5.8, and 8.0um, respectively, while it is 6.0", 18.0", and 40.0" in
the MIPS bands centered at 24, 70, and 160um, respectively. In our
study, we have used the simultaneous IRAC data only, in order to
minimize uncertainties of the selection procedure.
In order to ascertain the blazar nature of sources from the MQS and
the FS lists, we searched for radio counterparts of the optically
detected sources in various radio sky surveys and catalogs given in
Table 1:
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Survey Telescope Frequency Beam size
(GHz) (")
----------------------------------------------------------------
SUMSS (1) MOST 0.843 43 x 43csc|δ|
AT20G (1) ATCA 5, 8, 20 9.9, 5.5, 2.4
PMN (3) Parkes 64m 4.85 252
ATPMN (4) ATCA 4.8, 6.8 1.8, 1.2
SMC multi (5) ATCA and Parkes 1.42/8.64 98/15
LMC dual (6) ATCA 4.8, 8.6 33, 20
SMC dual (7) ATCA 4.8, 8.6 35, 22
----------------------------------------------------------------
Note. Sky survey references as follows:
(1) = Bock+ (1999AJ....117.1578B 1999AJ....117.1578B);
(1) = Murphy+ (2010, J/MNRAS/402/2403);
(3) = Griffith & Wright (1993, VIII/38);
(4) = McConnell+ (2012, J/MNRAS/422/1527);
(5) = Filipovic+ (2002, J/MNRAS/335/1085);
(6) = Dickel+ (2005AJ....129..790D 2005AJ....129..790D);
(7) = Dickel+ (2010AJ....140.1511D 2010AJ....140.1511D).
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 106 48 The radio fluxes of flat-spectrum radio quasar
(FSRQ) type blazar candidates
table3.dat 78 44 Newly identified FSRQ and BL Lac type blazar
candidates
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See also:
VIII/38 : The Parkes-MIT-NRAO 4.85GHz (PMN) Surveys (Griffith+ 1993-1996)
IX/10 : ROSAT All-Sky Bright Source Catalogue (Voges+ 1999)
VIII/81 : Sydney University Molonglo Sky Survey (SUMSS V2.1) (Mauch+ 2008)
VII/274 : The Roma BZCAT - 5th edition (Massaro+, 2015)
J/AJ/115/1253 : Deep X-Ray Radio Blazar Survey (DXRBS). I. (Perlman+ 1998)
J/A+AS/139/277 : LMC X-ray sources ROSAT PSPC catalogue (Haberl+, 1999)
J/A+AS/142/41 : SMC X-ray sources ROSAT PSPC catalogue (Haberl+, 2000)
J/MNRAS/323/757 : Deep X-Ray Radio Blazar Survey (DXRBS). II. (Landt+, 2001)
J/MNRAS/329/877 : The CLASS blazar survey. II. (Caccianiga+, 2002)
J/MNRAS/335/1085 : ATCA SMC Radio Continuum Source. I. (Filipovic+, 2002)
J/AJ/123/855 : Magellanic Clouds Photometric Survey: SMC (Zaritsky+, 2002)
J/AJ/128/1606 : Magellanic Clouds Photometric Survey: LMC (Zaritsky+, 2004)
J/AJ/132/2268 : SAGE calibration stars (Meixner+, 2006)
J/ApJ/655/212 : S3MC IRAC and MIPS photometry (Bolatto+, 2007)
J/AJ/134/799 : Multiwaveband polarimetry of 15 AGN (Jorstad+, 2007)
J/ApJ/698/895 : Variations in QSOs optical flux (Kelly+, 2009)
J/ApJ/701/508 : 5000 AGNs behind the Magellanic clouds (Kozlowski+, 2009)
J/ApJ/715/429 : First Fermi-LAT AGN catalog (1LAC) (Abdo+, 2010)
J/ApJ/718/587 : The Fermi-AT20G catalog (Mahony+, 2010)
J/MNRAS/402/2403 : Australia Telescope 20GHz Survey Catalog, (Murphy+, 2010)
J/AJ/139/390 : Opt selected BL Lac objects from SDSS-DR7 (Plotkin+, 2010)
J/ApJS/194/22 : Magellanic QSOs Survey: QSOs behind SMC (Kozlowski+, 2011)
J/ApJ/748/68 : WISE IR colors of gamma-ray blazars (D'Abrusco+, 2012)
J/ApJ/746/27 : Magellanic QSOs Survey.II.AGNs behind LMC (Kozlowski+, 2012)
J/ApJ/759/25 : Rotation measures at 1.4GHz toward the LMC (Mao+, 2012)
J/MNRAS/422/1527 : Australia Telescope PMN follow-up survey (McConnell+, 2012)
J/ApJS/199/31 : Fermi LAT second source catalog (2FGL) (Nolan+, 2012)
J/ApJ/775/92 : MQS III: AGNs behind LMC and SMC (Kozlowski+, 2013)
J/ApJ/767/14 : MASIV survey III. Optical identifications (Pursimo+, 2013)
J/A+A/549/A29 : Quasars behind the Magellanic system (Cioni+, 2013)
J/ApJS/215/14 : WISE candidate γ-ray blazar radio (D'Abrusco+, 2014)
J/other/Nat/515.376 : Relativistic jet powers in blazars (Ghisellini+, 2014)
J/other/AstBu/69.266 : RATAN-600 flux densities 37 blazars (Mufakharov+,2014)
J/MNRAS/450/2658 : RATAN-600 flux densities of 123 blazars (Mufakharov+, 2015)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 1 I1 --- Set [1/2] Subset (G1)
3- 12 A10 --- Name Shortened object name (JHHMM+DDMM)
as in Table 3 (G2)
14- 14 A1 --- f_Name [a] Flag on Name: a=Dubious Source
16- 20 F5.1 mJy F0.84 [6/177]? SUMSS/MOST 0.843GHz flux density
22- 24 F3.1 mJy e_F0.84 [0.8/8]? Uncertainty in F0.84
26- 30 F5.1 mJy F1.42 [45/112]? ATCA/Parkes SMC 1.42GHz
flux density
32- 34 F3.1 mJy e_F1.42 [2/6]? Uncertainty in F1.42
36- 39 F4.1 mJy F2.37 [4/77.4]? ATCA/Parkes SMC 2.37GHz
flux density
41- 43 F3.1 mJy e_F2.37 [0.2/4]? Uncertainty in F2.37
45- 50 F6.2 mJy F4.8 [2.8/288]? ATCA/Parkes 4.8GHz flux density
52- 55 F4.1 mJy e_F4.8 [0.7/15]? Uncertainty in F4.8
57- 57 A1 --- f_F4.8 [e] Flag on F4.8 (1)
59- 62 F4.1 mJy F4.85 [26/95]? PMN Parkes 64m 4.85GHz
flux density
64- 66 F3.1 mJy e_F4.85 [6/8]? Uncertainty in F4.85
68- 71 F4.1 mJy F5.0 [17/72]? AT20G/ATCA 5.0GHz flux density
73- 75 F3.1 mJy e_F5.0 [2/7]? Uncertainty in F5.0
77- 80 F4.1 mJy F8.0 [56/72]? AT20G/ATCA 8.0GHz flux density
82- 84 F3.1 mJy e_F8.0 [3/4]? Uncertainty in F8.0
86- 90 F5.2 mJy F8.6 [6/61]? ATCA/Parkes 8.6GHz flux density
92- 95 F4.1 mJy e_F8.6 [1/10]? Uncertainty in F8.6
97- 97 A1 --- f_F8.6 [e] Flag on F8.6 (1)
99-102 F4.1 mJy F20.0 [46/74]? AT20G/ATCA 20.0GHz flux density
104-106 F3.1 mJy e_F20.0 [3/4]? Uncertainty in F20.0
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Note (1): The 4.8 and 8.6GHz flux-densities flagged with "e" are measured
by authors based on the 4.8 and 8.6GHz ATCA radio surveys of the MCs
i.e., Dickel et al. (2005AJ....129..790D 2005AJ....129..790D) for LMC and Dickel et al.
(2010AJ....140.1511D 2010AJ....140.1511D) for SMC. Unflagged 4.8 and 8.6GHz measurements
are drawn from multiple surveys. See the "Description" section above.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 1 I1 --- Set [1/2] Subset (G1)
3- 12 A10 --- Name Shortened object name (JHHMM+DDMM) (G2)
14- 14 A1 --- f_Name [a] Flag on name, a=Dubious Source
16- 17 I2 h RAh [0/6] Hour of right ascension (J2000) (1)
18- 20 I3 min RAm Minute of right ascension (J2000) (1)
21- 26 F6.2 s RAs Second of right ascension (J2000) (1)
28 -28 A1 --- DE- [-] Sign of the declination (J2000) (1)
29- 30 I2 deg DEd [66/73] Degree of declination (J2000) (1)
31- 33 I3 arcmin DEm Arcminute of declination (J2000) (1)
34- 39 F6.2 arcsec DEs Arcsecond of declination (J2000) (1)
41- 44 I4 --- R [12/7020]? Radio-loudness R parameter (2)
46- 50 F5.3 --- z [0.2/3.4]? Redshift (1)
52- 56 F5.2 --- ar [-0.6/1.4]? Radio spectral index αr
58- 61 F4.2 --- e_ar [0/0.4]? Uncertainty in ar
63- 67 F5.2 --- aIR [-0.5/3.1]? Mid-IR spectral index αIR
69- 72 F4.2 --- e_aIR [0/0.5]? Uncertainty in aIR
74- 78 F5.2 mag Imag [16.5/21.3] I band magnitude (1)
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Note (1): The coordinates, z, and I band magnitude for the FSRQ type blazars
were taken from the MQS catalogue (Kozlowski+ J/ApJ/775/92).
The coordinates and I band magnitudes for the BL Lac type blazars were
taken from the featureless spectra list ("FS" list -- priv. comm.)
Note (2): R=F5GHz/FB≥10; see Kellermann+ (1989AJ.....98.1195K 1989AJ.....98.1195K);
Stocke+ (1992ApJ...396..487S 1992ApJ...396..487S); Ho (2002ApJ...564..120H 2002ApJ...564..120H).
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Global notes:
Note (G1): Subset flag as follows:
1 = FSRQ blazar type candidates (27 occurrences);
2 = BL Lac type blazar candidates (17 occurrences).
Note (G2): Sources from the Magellanic Quasars Survey (MQS;
Kozlowski+, 2012, J/ApJ/746/27) are named in Simbad.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie FIX [CDS] 16-Oct-2019