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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 (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 File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 490 192 Subdwarf candidates with good SED fit table2.dat 490 110 Hot sd candidates with IR excess in the SED fit table3.dat 490 115 Hot sd candidates with bad SED fits table4.dat 490 20 Hot sd candidates without IR photometric data
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
Bytes Format Units Label Explanations
1- 4 A4 --- --- [SDSS] 6- 24 A19 --- SDSS SDSS designation ( 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)
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
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 24-Nov-2016
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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