J/MNRAS/457/3396 New hot subdwarf stars (Perez-Fernandez+, 2016)
A search for new hot subdwarf stars by means of virtual observatory tools. II.
Perez-Fernandez E., Ulla A., Solano E., Oreiro R., Rodrigo C.
<Mon. Not. R. Astron. Soc., 457, 3396-3408 (2016)>
=2016MNRAS.457.3396P 2016MNRAS.457.3396P (SIMBAD/NED BibCode)
ADC_Keywords: Stars, early-type ; Stars, subdwarf ; Photometry, infrared ;
Photometry, SDSS ; Photometry, ultraviolet
Keywords: astronomical data bases: miscellaneous - virtual observatory tools -
stars: early-type - subdwarfs
Abstract:
Recent massive sky surveys in different bandwidths are providing new
opportunities to modern astronomy. The Virtual Observatory (VO)
represents the adequate framework to handle the huge amount of
information available and filter out data according to specific
requirements. In this work, we applied a selection strategy to find
new, uncatalogued hot subdwarfs making use of VO tools. We used large
area catalogues like GALEX, Sloan Digital Sky Survey (SDSS),
SuperCosmos and Two Micron All Sky Survey (2MASS) to retrieve
photometric and astrometric information of stellar objects. To these
objects, we applied colour and proper motion filters, together with an
effective temperature cutoff, aimed at separating hot subdwarfs from
other blue objects such as white dwarfs, cataclysmic variables or
main-sequence OB stars. As a result, we obtained 437 new, uncatalogued
hot subdwarf candidates. Based on previous results, we expect our
procedure to have an overall efficiency of at least 80 per cent.
Visual inspection of the 68 candidates with SDSS spectrum showed that
65 can be classified as hot subdwarfs: 5 sdOs, 25 sdOBs and 35 sdBs.
This success rate above 95 per cent proves the robustness and
efficiency of our methodology. The spectral energy distribution of 45
per cent of the subdwarf candidates showed infrared excesses, a
signature of their probable binary nature. The stellar companions of
the binary systems so detected are expected to be late-type
main-sequence stars. A detailed determination of temperatures and
spectral classification of the cool companions will be presented in a
forthcoming work.
Description:
In that work, a hot sd selection procedure was defined and tested by
means of a thorough retrieval, with the aid of VO tools, of
multicolour photometry and astrometric information from stellar
catalogues. A filtering procedure to distinguish among different types
of objects was designed to obtain a hot sd sample with a low
contamination factor. The method was tested on two sky regions: the
Kepler FoV2 and a region of 300deg2 around (RA:225°,DE:5°)
obtaining a high rate of success (above 80 per cent) in finding new
uncatalogued hot sds. Temperatures were provided by fitting their
spectral energy distribution (SED), and considering two-atmosphere
fits for those objects with a clear infrared (IR) excess, a signature
of the possible presence of a cool companion.
The complete table can be found at
http://svo2.cab.inta-csic.es/vocats/hsa/
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 465 192 Subdwarf candidates with good SED fit
table2.dat 465 110 Hot sd candidates with IR excess in the SED fit
table3.dat 490 115 Hot sd candidates with bad SED fits
table4.dat 465 20 Hot sd candidates without IR photometric data
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
II/294 : SDSS Photometric Catalog Release 7 (Adelman-McCarthy+, 2009)
J/MNRAS/427/2180 : GALEX survey subdwarf atmospheric parameters (Nemeth+, 2012
Byte-by-byte Description of file: table[1234].dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS SDSS designation (JHHMMSS.ss+DDMMSS.s)
26- 35 F10.6 deg RAdeg Rigth ascension (J2000)
37- 46 F10.6 deg DEdeg Declination (J2000)
48- 65 F18.15 mag NUV GALEX NUV magnitude (1)
67- 84 F18.15 mag FUV GALEX FUV magnitude (1)
86-106 F21.19 mag e_NUV rms uncertainty on NUV
108-129 F22.20 mag e_FUV rms uncertainty on FUV
130-135 F6.3 mag umag ? SDSS DR7 u magnitude
137-142 F6.3 mag gmag ? SDSS DR7 g magnitude
144-149 F6.3 mag rmag ? SDSS DR7 r magnitude
151-156 F6.3 mag imag ? SDSS DR7 i magnitude
158-163 F6.3 mag zmag ? SDSS DR7 z magnitude
165-169 F5.3 mag e_umag ? rms uncertainty on umag
171-175 F5.3 mag e_gmag ? rms uncertainty on gmag
177-181 F5.3 mag e_rmag ? rms uncertainty on rmag
183-187 F5.3 mag e_imag ? rms uncertainty on imag
189-193 F5.3 mag e_zmag ? rms uncertainty on zmag
195-200 F6.3 mag Jmag ? 2MASS J magnitude
202-207 F6.3 mag Hmag ? 2MASS H magnitude
209-214 F6.3 mag Kmag ? 2MASS J magnitude
216-220 F5.3 mag e_Jmag ? rms uncertainty on Jmag
222-226 F5.3 mag e_Hmag ? rms uncertainty on Hmag
228-232 F5.3 mag e_Kmag ? rms uncertainty on Kmag
234-236 A3 --- 2flag 2MASS flag (2)
245-255 F11.9 mag E(B-V) ? Redenning
257-274 F18.15 --- RPM ? Reduced proper motion
276-284 A9 --- objID Internal catalog identifier
286-292 F7.1 K Teff1 ? Effective temperature
(best SED fit performed by VOSA)
302-310 A9 kK TeffInt Effective temperature interval (3)
319-321 I3 --- Fflag Fit flag (4)
328-330 A3 --- SpTypeSec Secondary component spectral type
339-340 A2 --- BandExc Photometric band from which the excess
is detected
353-369 A17 --- Class MK-like spectral classification
371-466 A96 --- url SDSS spectrum url
468-490 A23 --- Pos Position, only in table3 (RA_X, DE_X)
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Note (1): FUV and NUV were taken from the GALEX archive (and corrected as
explained in the text, if necessary).
Note (2): We included the 2MASS quality flags of the source, where 'U' stands
for upper limit in the corresponding photometric value.
Note (3): An interval in the temperature column is given whenever the Bayes
analysis gave the most likely Teff value with a probability below 80 per cent.
Note (4): Set fitting quality flag as follows:
First digit:
5 = GOOD SED fitting
4 = IR excess
3 = IR and UV excess
2 = UV excess
1 = bad fitting
Second digit:
1 = GALAX artifact
0 = No problem condition
Third difit:
1 = GALEX photometric flag
0 = No problem condition
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 24-Nov-2016