2011A&A...530A...2O


Query : 2011A&A...530A...2O

2011A&A...530A...2O - Astronomy and Astrophysics, volume 530A, 2-2 (2011/6-1)

A search for new hot subdwarf stars by means of Virtual Observatory tools.

OREIRO R., RODRIGUEZ-LOPEZ C., SOLANO E., ULLA A., OSTENSEN R. and GARCIA-TORRES M.

Abstract (from CDS):

Recent massive sky surveys in different bandwidths are providing new opportunities to modern astronomy. The Virtual Observatory (VO) provides the adequate framework to handle the huge amount of information available and filter out data according to specific requirements. Hot subdwarf stars are faint, blue objects, and are the main contributors to the far-UV excess observed in elliptical galaxies. They offer an excellent laboratory to study close and wide binary systems, and to scrutinize their interiors through asteroseismology, since some of them undergo stellar oscillations. However, their origins are still uncertain, and increasing the number of detections is crucial to undertake statistical studies. In this work, we aim at defining a strategy to find new, uncatalogued hot subdwarfs. Making use of VO tools we thoroughly search stellar catalogues to retrieve multi-colour photometry and astrometric information of a known sample of blue objects, including hot subdwarfs, white dwarfs, cataclysmic variables and main-sequence OB stars. We define a procedure to distinguish among these spectral classes, which is particularly designed to obtain a hot subdwarf sample with a low contamination factor. To check the validity of the method, this procedure is then applied to two test sky regions: to the Kepler FoV and to a test region of 300deg2 around (α:225, δ:5deg). As a result of the procedure we obtained 38 hot subdwarf candidates, 23 of which had already a spectral classification. We have acquired spectroscopy for three other targets, and four additional ones have an available SDSS spectrum, which we used to determine their spectral type. A temperature estimate is provided for the candidates based on their spectral energy distribution, considering two-atmospheres fit for objects with clear infrared excess as a signature of the presence of a cool companion. Eventually, out of 30 candidates with spectral classification, 26 objects were confirmed to be hot subdwarfs, which means a contamination factor of only 13%. The high rate of success demonstrates the validity of the proposed strategy to find new uncatalogued hot subdwarfs. An application of this method to the entire sky will be presented in a forthcoming work.

Abstract Copyright:

Journal keyword(s): stars: early-type - subdwarfs - astronomical databases: miscellaneous - Virtual Observatory tools

VizieR on-line data: <Available at CDS (J/A+A/530/A2): table3.dat table7.dat>

Simbad objects: 81

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Number of rows : 81
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 NAME SGP reg 00 51 26.275 -27 07 41.70           ~ 555 0
2 FBS 1412+004 HS? 14 14 35.2410169848 +00 12 35.172987732   15.88 15.7     sd 8 0
3 EGGR 439 WD* 14 24 37.3513885776 +02 34 18.807970512   16.9 16.77 16.6   DA2.3 12 0
4 PG 1532+034 WD* 15 35 09.8583983712 +03 11 15.411565248   15.14   15.8   DA.8 21 0
5 EGGR 491 HS* 15 43 38.6865366216 +00 12 02.159635284   17.19 16.75 16.49   sdB 16 0
6 GALEX J181948.3+332209 HS* 18 19 48.3180167352 +33 22 09.734409948           sdB 4 0
7 GALEX J182054.6+331846 HS? 18 20 54.7211742288 +33 18 46.612933488           ~ 4 0
8 GALEX J182057.7+370707 HS? 18 20 57.6855266304 +37 07 07.454147484           ~ 3 0
9 FBS 1819+348 HS* 18 21 09.7238087640 +34 46 44.271555564           sdOB 7 0
10 GALEX J182150.0+415155 HS? 18 21 50.0075702640 +41 51 56.305511064           sd+F/K 4 0
11 GALEX J182242.8+432037 HS* 18 22 42.8321981736 +43 20 38.850876564           sdOBHe 6 0
12 GALEX J182310.0+333353 HS? 18 23 10.1649106872 +33 33 53.725646484       15.31   ~ 3 0
13 FBS 1822+414 HS* 18 23 56.8043639736 +41 29 14.613810324   14.34 14.76     sdBO 12 0
14 GALEX J182359.6+515525 HS? 18 23 59.6058089976 +51 55 26.994109512   15.64 15.85     ~ 3 0
15 FBS 1822+352 WD* 18 24 08.2452394608 +35 16 18.664218624           DA 9 0
16 UCAC2 45189636 HS? 18 24 34.3925566008 +38 00 55.684252548       16.14   ~ 3 0
17 UCAC4 628-059367 HS? 18 24 43.4126083536 +35 30 42.780679488       16.19   ~ 3 0
18 GALEX J182448.7+385138 HS? 18 24 48.7323887952 +38 51 37.753091424       16.35   ~ 3 0
19 GALEX J182518.7+403333 HS? 18 25 18.7619398968 +40 33 33.737408676   15.84 15.94     ~ 3 0
20 UCAC2 43294177 HS? 18 26 22.5187034400 +32 51 07.810546428       15.36   ~ 4 0
21 GALEX J182637.0+343726 HS? 18 26 37.0599465864 +34 37 26.443182648       15.89   ~ 4 0
22 GALEX J182744.7+370931 HS? 18 27 44.7249251952 +37 09 31.070603556           ~ 3 0
23 GALEX J182754.9+362207 HS? 18 27 54.9173080872 +36 22 08.075364672           ~ 3 0
24 GALEX J182849.9+343650 HS? 18 28 49.9402891464 +34 36 49.935632976           ~ 3 0
25 GALEX J183221.4+550259 HS? 18 32 21.3998306064 +55 02 59.502549840           ~ 4 0
26 GALEX J183344.2+430106 HS? 18 33 44.3270547864 +43 01 06.421824516   16.16 16.21     ~ 3 0
27 GALEX J183454.2+444917 HS? 18 34 54.1281804024 +44 49 16.542543108   14.82 14.70 14.82   ~ 2 1
28 FBS 1833+434 HB* 18 35 16.9502335176 +43 27 30.769223976   14.29 14.19     B2 6 0
29 SDSS J183620.82+405938.5 HS? 18 36 20.8290155424 +40 59 38.488569036           ~ 4 0
30 GALEX J183634.3+531657 HS? 18 36 34.2688631952 +53 16 57.333970992   12.27 12.45 12.68   ~ 3 0
31 GALEX J183642.4+413045 HS? 18 36 42.4650698808 +41 30 47.152873476           sdB: 5 0
32 GALEX J183948.5+530004 HS? 18 39 48.4968759264 +53 00 03.700586376   15.97 16.07 16.32   ~ 3 0
33 UCAC4 659-066574 HS? 18 40 20.8765963104 +41 43 14.366456148   14.62 14.90 15.13   ~ 3 0
34 GALEX J184202.9+453159 HS? 18 42 02.8121927880 +45 31 59.077517448   14.10 14.39     ~ 4 0
35 2MASS J18424248+4404055 Er* 18 42 42.4919250048 +44 04 05.580458256           sdB 10 0
36 2MASS J18430679+4259180 HS* 18 43 06.7738433496 +42 59 18.070319076           sdO+dM 15 0
37 UCAC4 679-063773 HS? 18 43 55.5585365904 +45 37 56.932408524   15.84 16.23 16.31   ~ 4 0
38 HS 1844+5048 ** 18 45 55.7855899248 +50 51 18.722852388           ~ 5 0
39 2MASS J18471411+4741468 HS* 18 47 14.1155691144 +47 41 46.790512260           sdOBHe 14 0
40 GALEX J184746.4+504134 HS* 18 47 46.2820262280 +50 41 34.885906188   14.27 14.58 15.00   sdB 4 0
41 GALEX J184915.1+511604 HS* 18 49 14.9870318352 +51 16 04.654141968   14.63 14.82 15.20   sdB 4 0
42 GALEX J185005.3+502422 HS? 18 50 05.2057797048 +50 24 21.931538652   15.38 15.20 15.38   ~ 3 0
43 2MASS J18501686+4358284 Pu* 18 50 16.8586159344 +43 58 28.668956412           B 4 0
44 UCAC4 706-060577 HS? 18 50 45.7882594080 +51 07 38.372341224   13.50 13.62 14.03   ~ 4 0
45 GALEX J185758.0+444057 HS? 18 57 58.0164909072 +44 40 56.882179308   16.60 16.38 16.14   ~ 4 0
46 GALEX J190343.8+472438 HS? 19 03 43.8529746768 +47 24 38.871104472   15.88 16.17 16.20   ~ 3 0
47 2MASS J19043482+4810221 HS* 19 04 34.8389008440 +48 10 22.245937932           sdB 6 0
48 FBS 1903+432 HS* 19 05 06.3763958616 +43 18 31.220048592   15.08 15.48     sdB 28 1
49 GALEX J190520.0+445759 HS? 19 05 20.0203461000 +44 57 59.107096908   17.09 16.98     ~ 3 0
50 2MASS J19082473+4508321 HS* 19 08 24.7487031288 +45 08 32.348656320           sdB 6 0
51 FBS 1907+425 HS* 19 08 45.8235961776 +42 38 31.051694976   15.24 15.36     sdB 13 0
52 GALEX J190920.1+454056 HS? 19 09 20.0194101504 +45 40 56.323421652   14.35 14.37 14.68   ~ 4 0
53 Kepler-429 HS* 19 09 33.4136944848 +46 59 04.108493616           sdB 28 0
54 2MASS J19100018+4640244 HS* 19 10 00.1843964976 +46 40 24.503781720           sdO+F/G 5 0
55 GALEX J191023.7+470944 Pu* 19 10 23.7195186960 +47 09 44.176514976   10.94 10.98     B2V 10 0
56 2MASS J19142762+4539094 HS* 19 14 27.6198709464 +45 39 09.622787616           sdB 9 0
57 2MASS J19150768+4754190 Pu* 19 15 07.6764289728 +47 54 18.924118236           B3V 15 0
58 2MASS J19161211+4749154 Er* 19 16 12.1066804632 +47 49 15.393417780           sdB+F/G 13 0
59 GALEX J192003.2+491533 HS? 19 20 03.2483925336 +49 15 32.233372956           ~ 4 0
60 UCAC4 691-065200 HS? 19 20 18.2537297160 +48 06 20.982040308   16.42 16.48     ~ 5 0
61 2MASS J19203620+4903158 V* 19 20 36.2094538104 +49 03 15.700605660           B5V 8 0
62 2MASS J19265139+4908484 Er* 19 26 51.3848988312 +49 08 48.331033512           sdB+F/G 12 0
63 GALEX J193049.4+542127 HS? 19 30 49.3941036432 +54 21 27.462238704           ~ 3 0
64 GALEX J193632.8+524518 HS? 19 36 32.8277569128 +52 45 18.518430204           ~ 2 0
65 2MASS J19403230+4827235 HS* 19 40 32.3047305672 +48 27 23.541278904           sdB+F/G 7 0
66 RE J1943+500 WD* 19 43 43.6811875272 +50 04 37.921728648     14.8     DA1.4 46 0
67 GALEX J194442.8+544942 HS? 19 44 42.8539557888 +54 49 42.888532548   15.80 15.82 15.70   ~ 4 0
68 GALEX J195023.6+500859 HS? 19 50 23.5646502744 +50 08 59.338704552   13.95 13.89     ~ 3 0
69 GALEX J195304.2+494934 HS? 19 53 04.2712734072 +49 49 34.337614332           ~ 5 0
70 GALEX J195342.0+495944 HS? 19 53 42.1548155688 +49 59 44.120698260   15.85 16.27 16.10   ~ 2 0
71 2MASS J19545230+4822282 Ro* 19 54 52.3109243352 +48 22 28.200625104           ~ 5 0
72 2MASS J19564769+5312177 HS? 19 56 47.6948368008 +53 12 17.524792872           ~ 3 0
73 GALEX J195728.4+533201 HS? 19 57 28.4205605304 +53 32 03.302600352   15.31 15.50 15.12   ~ 5 0
74 V* V476 Cyg No* 19 58 24.5056065864 +53 37 06.921041340           ~ 105 0
75 LS III +54 101 Pu* 19 59 18.5932516464 +54 20 11.930938728   11.91 11.98     OB- 5 0
76 GALEX J200001.2+540902 HS? 20 00 01.2631522584 +54 09 03.107617308   12.98 12.87 13.02   ~ 1 0
77 GALEX J200154.3+490354 HS? 20 01 54.3429326376 +49 03 54.316044864       15.95   ~ 4 0
78 BD+48 3035 * 20 06 32.6630496816 +48 33 28.581140232   9.66 9.58     A0 3 0
79 GALEX J200739.0+544516 HS? 20 07 39.1131732576 +54 45 16.598237148           ~ 3 0
80 GALEX J200934.4+550525 HS? 20 09 34.4136067632 +55 05 25.788763176           ~ 2 0
81 AP J20115228+5450117 HS? 20 11 52.2963732744 +54 50 11.807305440   10.77 10.41     ~ 2 0

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2023.02.04-10:59:14

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