J/A+A/622/A29 SMC AGN in XMM-Newton (Maitra+, 2019)
Identification of AGN in the XMM-Newton X-ray survey of the SMC.
Maitra C., Haberl F., Ivanov V.D., Cioni M.-R.L., van Loon J.T.
<Astron. Astrophys., 622, A29 (2019)>
=2019A&A...622A..29M 2019A&A...622A..29M (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; QSOs ; X-ray sources ; Infrared sources
Keywords: Magellanic Clouds - quasars: general - X-rays: galaxies -
infrared: galaxies - catalogs
Abstract:
Finding active galactic nuclei (AGN) behind the Magellanic Clouds
(MCs) is difficult because of the high stellar density in these
fields. Although the first AGN behind the Small Magellanic Cloud (SMC)
were reported in the 1980s, it is only recently that the number of AGN
known behind the SMC has increased by several orders of magnitude.
The mid-infrared colour selection technique has proven to be an
efficient means of identifying AGN, especially obscured sources. The
X-ray regime is complementary in this regard and we use XMM-Newton
observations to support the identification of AGN behind the SMC.
We present a catalogue of AGN behind the SMC by correlating an updated
X-ray point-source catalogue from our XMM-Newton survey of the SMC
with previously identified AGN from the literature as well as a list
of candidates obtained from the ALLWISE mid-infrared colour-selection
criterion. We studied the properties of the sample with respect to
their redshifts, luminosities, and X-ray spectral characteristics. We
also identified the near-infrared counterpart of the sources from the
VISTA observations.
The redshift and luminosity distributions of the sample (where known)
indicate that we detect sources ranging from nearby Seyfert galaxies
to distant and obscured quasars. The X-ray hardness ratios are
compatible with those typically expected for AGN, and the VISTA
colours and variability are also consistent with AGN. A positive
correlation was observed between the integrated X-ray flux (0.2-12keV)
and the ALLWISE and VISTA magnitudes. We further present a sample of
new candidate AGN and candidates for obscured AGN. Together these make
an interesting subset for further follow-up studies. An initial
spectroscopic follow-up of 6 out of the 81 new candidates showed that
all six sources are active galaxies, although two have narrow emission
lines.
Description:
The sample contains 81 newly identified candidates (with 59 being
introduced for the first time as AGN candidates) which were selected
using the ALLWISE mid-IR colours but with a lower S/N criterion than
used by Secrest et al. (2015. Cat. J/ApJS/221/12). An initial optical
spectroscopic follow-up of 6 out of the 81 candidates confirmed that
all six are AGN.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 103 81 Newly identified AGN candidates from the
XMM-Newton SMC survey selected using ALLWISE
mid-IR colour selection
tablea4.dat 93 20 Identified candidates for obscured AGN
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See also:
J/A+A/558/A3 : XMM-Newton point-source catalogue of the SMC (Sturm+, 2013)
J/ApJS/221/12 : AGNs in the MIR using AllWISE data (Secrest+, 2015)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq [1/81] Candidate sequential number
4- 22 A19 --- Name Designation (JHHMMSS.ss+DDMMSS.s)
24- 30 F7.4 deg RAdeg Right ascension (J2000)
32- 39 F8.4 deg DEdeg Declination (J2000)
41- 46 F6.4 arcsec ePos Positional error
48- 52 F5.3 --- X ALLWISE source X colour (f12um/f4.6um)
54- 59 F6.3 --- Y ALLWISE source Y colour (f4.6um/f3.4um)
61- 66 F6.4 10-14W/m2 FX X-ray flux in 0.2-12keV band
68- 73 F6.4 10-14W/m2 e_FX rms uncertainty on FX
75- 80 F6.3 mag Y-J ?=0 VISTA counterpart Y-J colour index
82- 86 F5.3 mag J-Ks ?=0 VISTA counterpart J-Ks colour index
88-103 A16 --- XMMid XMM designation (JHHMMSS.s+DDMMSS) (G1)
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Byte-by-byte Description of file: tablea4.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- Name Designation (JHHMMSS.ss+DDMMSS.s or
NNN.NNNNN.NNN for MACHO sources)
21- 27 F7.4 deg RAdeg Right ascension (J2000)
29- 36 F8.4 deg DEdeg Declination (J2000)
38- 43 F6.4 arcsec ePos Positional error
45- 50 F6.4 10-14W/m2 FX X-ray flux in 0.2-12keV band
52- 57 F6.4 10-14W/m2 e_FX rms uncertainty on FX
59- 64 F6.3 --- HR2 Hardness ratio 2 (0.5-1.0 keV)
66- 70 F5.2 --- HR3 Hardness ratio 3 (1.0-2.0 keV)
72- 76 F5.2 --- HR4 Hardness ratio 4 (2.0-4.5 keV)
78- 93 A16 --- XMMid XMM designation (JHHMMSS.s+DDMMSS) (G1)
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Global notes:
Note (G1): for sources already included in Sturm et al.
(2013, Cat. J/A+A/558/A3).
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 01-Apr-2019