J/AJ/155/46 Extragalactic candidates in the VVV survey (Baravalle+, 2018)
Searching for extragalactic sources in the VISTA Variables in the Via Lactea
survey.
Baravalle L.D., Alonso M.V., Castellon J.L.N., Beamin J.C., Minniti D.
<Astron. J., 155, 46 (2018)>
=2018AJ....155...46B 2018AJ....155...46B (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Photometry, infrared ; Morphology
Keywords: catalogs - galaxies: fundamental parameters - galaxies: photometry -
surveys
Abstract:
We search for extragalactic sources in the VISTA Variables in the Via
Lactea survey that are hidden by the Galaxy. Herein, we describe our
photometric procedure to find and characterize extragalactic objects
using a combination of SExtractor and PSFEx. It was applied in two tiles
of the survey: d010 and d115, without previous extragalactic IR detections,
in order to obtain photometric parameters of the detected sources. The
adopted criteria to define extragalactic candidates include CLASS_STAR<0.3;
1.0<R1/2<5.0 arcsec; 2.1<C<5; and Φ>0.002 and the colors:
0.5<(J-Ks)<2.0 mag; 0.0<(J-H)<1.0 mag; 0.0<(H-Ks)<2.0 mag and
(J-H)+0.9(H-Ks)>0.44 mag. We detected 345 and 185 extragalactic
candidates in the d010 and d115 tiles, respectively. All of them were
visually inspected and confirmed to be galaxies. In general, they are
small and more circular objects, due to the near-IR sensitivity to select
more compact objects with higher surface brightness. The procedure will be
used to identify extragalactic objects in other tiles of the VVV disk,
which will allow us to study the distribution of galaxies and filaments
hidden by the Milky Way.
Description:
The VISTA Variables in the Via Lactea (VVV; Minniti et al.
2010NewA...15..433M 2010NewA...15..433M) is a public European Southern Observatory (ESO)
near-IR variability survey covering the Milky Way (MW) Bulge
(-10°<l<+10° and -10°<b<+5°) and an adjacent section
of the mid-plane (-65°<l< -10° and -2°<b<+2°). This large
survey offers an excellent opportunity to study extragalactic sources
behind the MW, such as background galaxies and quasars. The 4 m VISTA
telescope at ESO is equipped with a VIRCAM camera (Dalton et al.
2006SPIE.6269E..0XD; Emerson et al. 2006Msngr.126...41E 2006Msngr.126...41E), which is an
array of 16x2048x2048 Raytheon VIRGO IR detectors with a scale of
0.339 arcsec/pix with five broad passbands: Z, Y, J, H, and Ks and
three narrow passbands at 0.98, 0.99, and 1.18 µm. The VVV is one
of the six largest ESO public surveys conducted using this telescope
without any overlapping regions. The VVV images (Tiles) are produced
by six single pointing observations with a total field of view of
1.64 square degrees.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 131 530 Photometric catalog of extragalactic candidates
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See also:
II/337 : VISTA Variables in the Via Lactea Survey DR1 (Saito+, 2012)
II/352 : The VISTA Hemisphere Survey (VHS) catalog (McMahon+, 2013)
II/348 : VISTA Variable in the Via Lactea Survey DR2 (Minniti+, 2017)
J/A+AS/141/123 : Galaxies behind Southern Milky Way (Kraan-Korteweg 2000)
J/A+A/380/441 : Galaxies behind Southern Milky Way. II. (Woudt+, 2001)
J/AJ/144/127 : 204 galaxy candidates from VVV infrared photometry
(Amores+, 2012)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [VVV]
4- 23 A20 --- VVV VVV designation (JHHMMSS.ss+DDMMSS.s)
25- 26 I2 h RAh Hour of Right Ascension (J2000.0)
28- 29 I2 min RAm Minute of Right Ascension (J2000.0)
31- 35 F5.2 s RAs Second of Right Ascension (J2000.0)
37 A1 --- DE- Sign of the Declination (J2000.0)
38- 39 I2 deg DEd Degree of Declination (J2000.0)
41- 42 I2 arcmin DEm Arcminute of Declination (J2000.0)
44- 47 F4.1 arcsec DEs Arcsecond of Declination (J2000.0)
49- 53 F5.2 mag Zmag [13.76/19.54]? PSF Z band magnitude
55- 59 F5.2 mag Ymag [13.98/19.04]? PSF Y band magnitude
61- 65 F5.2 mag Jmag [13.63/19.13]? PSF J band magnitude
67- 71 F5.2 mag Hmag [13.22/17.64] PSF H band magnitude
73- 77 F5.2 mag Ksmag [13.18/16.65] PSF Ks band magnitude
79- 83 F5.2 mag Zmag2 [14.09/19.39]? Z band aperture magnitude within
a diameter of 2 arcsec
85- 89 F5.2 mag Ymag2 [14.22/18.88]? Y band aperture magnitude within
a diameter of 2 arcsec
91- 95 F5.2 mag Jmag2 [13.83/18.72] J band aperture magnitude within
a diameter of 2 arcsec
97-101 F5.2 mag Hmag2 [13.29/17.32] H band aperture magnitude within
a diameter of 2 arcsec
103-107 F5.2 mag Ksmag2 [13.11/16.71] Ks band aperture magnitude
within a diameter of 2 arcsec
109-112 F4.2 arcsec R1/2 [1.01/4.87] Half-light radius R1/2
114-117 F4.2 --- C [2.1/4.44] Concentration index
119-122 F4.2 --- e [0.01/0.78] Ellipticity ε
124-127 F4.2 --- n [0.3/9.79] Spheroid Sersic index
129-131 A3 --- Com Comment(s) about the object morphology and
the contamination by nearby stars (1)
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Note (1): Comment as follows:
1 = Galaxy pair;
2 = Late-type galaxy: elongated shape;
3 = Late-type galaxy: with spiral arms;
4 = Early-type galaxy: bright elliptical galaxy;
5 = Star near the galaxy nucleus.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 25-Sep-2018