2003AJ....125.2239O

Query : 2003AJ....125.2239O

2003AJ....125.2239O - Astron. J., 125, 2239-2254 (2003/April-0)

Hard X-ray emission associated with white dwarfs.

O'DWYER I.J., CHU Y.-H., GRUENDL R.A., GUERRERO M.A. and WEBBINK R.F.

Abstract (from CDS):

Inspired by the hard X-ray emission from WD 2226-210, the central star of the Helix Nebula, we have made a systematic search for similar sources by correlating the white dwarf catalog of McCook & Sion and the ROSAT Position Senstive Proportional Counter (PSPC) point-source catalog of White, Giommi, & Angelini. We find 76 white dwarfs coincident with X-ray sources at a high level of confidence. Among these sources, 17 show significant hard X-ray emission at energies greater than 0.5 keV. Twelve of these white dwarfs with hard X-ray emission are in known binary systems, in two of which the accretion of the close companion's material onto the white dwarf produces hard X-ray emission, and in the other 10 the late-type companions' coronal activity emits hard X-rays. One apparently single white dwarf is projected near an active galactic nucleus that is responsible for the hard X-ray emission. The remaining four white dwarfs and two additional white dwarfs with hard X-ray emission appear single. The lack of near-IR excess from the apparently single white dwarfs suggests that either X-ray observations are more effective than near-IR photometry in diagnosing faint companions, or a different emission mechanism is needed. It is intriguing that 50% of the six apparently single white dwarfs with hard X-ray emission are among the hottest white dwarfs. We have compared X-ray properties of 11 hot white dwarfs with different spectral types and conclude that stellar pulsation and fast stellar winds are not likely the origin of the hard X-ray emission, but a leakage of the high-energy Wien tail of emission from deep in the stellar atmosphere remains a tantalizing source of hard X-ray emission from hot DO and DQZO white dwarfs. A complete survey using the entire ROSAT PSPC archive is needed to enlarge the sample of white dwarfs with hard X-ray emission. Follow-up near-IR photometric observations are needed to verify the existence of late-type companions, and high-resolution deep X-ray observations are needed to verify the positional coincidence and to study the X-ray spectral properties in order to determine the origin and nature of the hard X-ray emission.

Abstract Copyright: ∼

Journal keyword(s): Stars: Binaries: General - Stars: Coronae - Stars: Late-Type - Stars: White Dwarfs - X-Rays

VizieR on-line data: <Available at CDS (J/AJ/125/2239): table1.dat>

Simbad objects: 98

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Number of rows : 98
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 PG 2357+297 WD* 00 00 07.2553163280 +29 57 00.478163124   14.77 12.24 15.63   DA.9 28 0
2 MCT 0027-6341 WD* 00 29 56.7251246112 -63 24 58.003740036   15.010 15.307 15.536   DA.8 51 0
3 GD 8 WD* 00 39 52.1658354768 +31 32 29.133060396 13.255 14.424 14.699 14.844 15.047 DA1.0 36 0
4 FOCAP SGP2:31 WD* 00 51 11.2877279040 -29 09 39.731693868   18.99 18.9     DA3.5 12 0
5 GD 659 WD* 00 53 17.4282107064 -32 59 56.523062760   13.14 13.36     DA1.4 140 0
6 Ton S 205 ** 01 18 37.185 -22 54 57.83   16.4 15.63 15.8 15.59 DA+M 22 0
7 RX J0122.9-7521 WD* 01 22 53.4122561952 -75 21 14.724358308     15.4     PG1159 47 0
8 GD 984 ** 01 34 24.0732015168 -16 07 08.095946556   13.6 13.98 14.3   DA1+dM 72 0
9 PG 0136+251 WD* 01 38 52.9776840264 +25 23 22.640581464   15.83       DA1.2 91 0
10 * omi Cet B WD* 02 19 20.80 -02 58 40.0           DA 52 1
11 LP 471-52 WD* 03 07 04.2419479608 +15 40 50.199741012   20.2   18.2   DC: 16 0
12 LB 1663 WD* 03 22 14.8200931320 -53 45 16.473401928   14.88 14.9 15.51 15.21 DA1.5 78 0
13 MCT 0333-3500 WD* 03 35 33.6931561080 -34 50 01.738125240   15.541 15.686 16.1   DA1.5 16 0
14 FOCAP QSF1:02 WD* 03 41 26.7257844120 -45 00 49.336832628   19.6   21.1   DA 8 0
15 V* V471 Tau SB* 03 50 24.9666549840 +17 14 47.430910716   10.258 9.373   8.393 K2V+DA 697 0
16 EC 04160-5505 WD* 04 17 11.3584671528 -54 57 47.217642408 14.01 15.13 15.35 15.80   DA 27 0
17 LAWD 19 WD* 04 28 39.4103640216 +16 58 12.094977036   13.96 14.03 14.51   DA2.0 135 0
18 EGGR 180 WD* 04 31 12.5714396826 +58 58 41.292707803 12.29 12.77   12.8   DC5 140 0
19 HZ 9 ** 04 32 23.7569977200 +17 45 02.672275356   14.28 13.93 14.21   DA3+dM 160 0
20 RX J0443.1-0346 WD* 04 43 07.1639093832 -03 46 49.791898632   16.7 16.0 16.8   DA.8 41 0
21 WG 47 WD* 04 43 46.4273702112 -78 51 50.182236864 12.36 13.304 13.418 13.764   DA2.1 53 1
22 RX J0521.3-1029 WD* 05 21 18.9703270488 -10 29 17.546990352   15.6 15.6 15.9   DA1.5 47 0
23 RX J0534.3-0214 WD* 05 34 20.3152933752 -02 14 31.219761264   15.85 15.84     DA1.7 30 0
24 GD 257 WD* 05 50 37.5195849864 +00 05 52.623285612   14.80 15.10 15.1   DA1.1 72 0
25 PN K 1-27 PN 05 57 02.1748457640 -75 40 22.478040120     16.04 16.27 16.41 sdOHe 91 0
26 GD 80 WD* 06 54 13.8072319632 -02 09 20.598940836   14.61 14.79 15.05   DA1.5 60 0
27 RX J0715.3-7025 WD* 07 15 16.5785943888 -70 25 05.616247620   13.97 14.178 14.12   DA1 58 0
28 V* IN CMa CV* 07 20 47.9109655416 -31 47 02.732961552           DAO+dM 93 0
29 Cl* NGC 2422 RA 1 WD? 07 36 33.5993687424 -14 32 05.760901608   19.2 19.5 20.4   DA/sdO 10 0
30 * alf CMi B WD* 07 39 17.8800 +05 13 26.800   10.7 10.92     DQZ 174 0
31 1RXS J080024.2-474601 WD* 08 00 24.0177702720 -47 46 01.613482608   17.7       DA 11 0
32 PG 0805+655 ** 08 09 45.435048 +65 18 17.70912   16.22 16.25     DA1.1 13 0
33 PG 0824+289 ** 08 27 05.0512752687 +28 44 02.778910836   14.391 14.204 14.454   DA+dC 71 0
34 RX J0841.0+0320 WD* 08 41 03.4311724896 +03 20 57.719634324     14.48     DA1.3 32 0
35 Cl* IC 2391 KR 1 WD* 08 41 08.6340402168 -52 59 39.975407808   18.1 19.7 18.9   DA 9 0
36 LB 1876 WD* 08 42 52.3105257384 +19 51 11.194802136   17.84 17.69     DA5 48 1
37 HD 74389B WD* 08 45 48.9561653856 +48 52 45.678931932   15.5       DA1.3 30 1
38 LP 426-57 WD* 09 05 55.7771118888 +16 25 10.310590236   20.2 19.16 18.8   DA: 14 0
39 PG 0904+512 WD* 09 07 47.7332869344 +50 57 49.604290884   16.13       DA1.5 36 0
40 1RXS J091657.6-194613 WD* 09 16 57.7063571088 -19 46 25.052161512       16.9   DA.8 31 0
41 PG 0937+506 WD* 09 40 22.6601336280 +50 21 05.882761872   16.06       DA1.4 53 0
42 PG 0954+697 WD* 09 58 30.8110886328 +69 28 59.009315304   15.87 15.96 16.0   DA2.2 34 0
43 PG 1010+065 WD* 10 13 28.1651586672 +06 12 07.314084252   16.30       DA1.1 35 0
44 SBSS 1029+537 WD* 10 32 09.9865348944 +53 29 35.373072660   14.095 14.453 14.831   DA1.1 90 0
45 PG 1040+452 WD* 10 43 32.6246801112 +44 53 28.982547348   16.94       DA1.1 45 0
46 LB 1919 WD* 10 59 16.4293648440 +51 24 43.125083064   15.5 16.8     DA.7 62 0
47 Ton 61 WD* 11 12 38.9116213800 +24 09 01.205285076   15.50 15.79 16.01   DA1.3 48 0
48 GD 140 WD* 11 37 05.1041466528 +29 47 58.288741080 11.47 12.42 12.45 12.73 12.714 DA2.2 257 0
49 PG 1144+005 WD* 11 46 35.2284791112 +00 12 33.539992056   14.922 15.233     PG1159 92 0
50 V* GW Vir WD* 12 01 45.9731868264 -03 45 40.628670300   14.87 15.04     DOQZ1 505 0
51 V* EG UMa CV* 12 15 44.0979312096 +52 31 01.289011692   13.0 13.230 13.149   DA+dM 119 1
52 7C 122915.40+290414.00 BLL 12 31 43.5724342752 +28 47 49.770870684   17.90 17.38     ~ 99 2
53 PG 1234+482 WD* 12 36 45.1436139768 +47 55 22.218366900     14.38     DA.9 98 2
54 PN LoTr 5 PN 12 55 33.7471108416 +25 53 30.559286040   9.72 8.88     G5III-IV 223 0
55 GD 153 WD* 12 57 02.3224909560 +22 01 52.634778240 11.883 13.060 13.349 13.488 13.669 DA1.2 380 0
56 HZ 43A WD* 13 16 21.8532409720 +29 05 55.411186877   12.52 12.66     DAwk 477 0
57 EGGR 188 WD* 13 19 13.7224549014 +45 05 09.802760414   14.16   14.3   DA3.6 65 0
58 EGGR 358 WD* 13 27 42.1659783000 +57 55 05.939444019   17.12   16.4   DA7.4 49 0
59 PG 1333+511 WD* 13 35 14.5342852344 +50 50 12.255625896   16.39       DA1.4 29 0
60 PG 1403-077 WD* 14 06 04.8463136448 -07 58 31.006552260   15.19   15.9   DA1.0 30 0
61 RE J144603+632856 WD* 14 46 02.1273744888 +63 29 23.937298872     15.7     DA1.2 33 0
62 PG 1501+664 WD* 15 02 09.6299323152 +66 12 19.148868324   16.07 16.37     DZQ1 163 0
63 HS 1522+6615 WD* 15 22 56.6956117920 +66 04 42.031760016   16.4       DO 25 0
64 CD-38 10980 WD* 16 23 33.8380498896 -39 13 46.161043572 9.916 10.885 11.029 10.936 10.841 DA2 526 0
65 RX J1629.0+7804 WD* 16 29 10.278576 +78 04 39.91620   12.74 12.95 13.03   DA1.2 86 0
66 EGGR 258 WD* 16 34 21.5518633862 +57 10 08.868180953       14.770   DQ8 132 0
67 PG 1636+351 WD* 16 38 26.3184985560 +35 00 11.890614960 13.585 14.65 14.902 15.013 15.157 DA1.4 89 0
68 HD 149499B WD* 16 38 31.199462 -57 28 10.70103   11.15 11.28     DOZ1 108 0
69 GD 357 WD* 16 43 02.2595999160 +38 41 17.210504868   14.69   15.0   DA3.1 51 0
70 FBS 1648+407 WD* 16 50 20.0665732968 +40 37 22.592997624     14.5     DA1.3 54 0
71 PG 1657+344 WD* 16 58 51.1124739360 +34 18 53.321336856   16.12       DA.9 70 0
72 PG 1658+441 WD* 16 59 48.4241073768 +44 01 04.038522204   14.3 14.6     DAP1.6 156 0
73 PG 1659+442 HS* 17 00 35.6649183192 +44 10 01.401508812   16.2   16.9   sdB 9 0
74 GD 372 WD* 18 04 23.4822025104 +21 21 02.785128048   15.5   16.3   DA3.0 26 0
75 PN K 1-16 PN 18 21 52.1086837968 +64 21 53.406292104   14.44 14.96 15.26   PG1159 258 0
76 BPS CS 22959-0081 WD* 18 49 02.0437975992 -65 25 14.476021788   15.7 15.2 14.7   DA 7 0
77 WD 1906-600.2 WD* 19 10.8 -59 59   20.70 20.78     DA3 5 0
78 WD 1906-600.3 WD* 19 10.8 -59 59   21.49 21.49     DA? 5 0
79 WD 1906-600.4 WD* 19 10.8 -59 59   21.76 21.77     DA? 4 0
80 WD 1906-600.1 WD* 19 10.8 -59 59   20.36 20.58     DC? 5 0
81 WD 1910+047 WD* 19 12 31.1674751112 +04 52 12.828060336   16.5 14 16.8   DA 19 0
82 CD-42 14462 CV* 19 47 40.5290567472 -42 00 26.395115580 9.65 10.362 10.308 10.520   sdB 243 0
83 M 27 PN 19 59 36.3631850088 +22 43 16.312059552   13.749 14.089 14.247 14.405 DAO.6 605 0
84 RX J2013.1+4002 ** 20 13 09.3685663800 +40 02 24.241439184     14.6     DAO+M2/3e 94 1
85 L 210-114 WD* 20 18 54.6880579032 -57 21 32.761860984 12.56 13.58 13.73 13.9   DA1.8 71 0
86 MCT 2020-4234 WD* 20 23 59.5069330104 -42 24 25.846993944 13.73 14.70 14.89     DA1.6 59 0
87 GD 391 WD* 20 29 56.1796812432 +39 13 32.199117348 12.243 13.218 13.373 13.481 13.623 DA2.0 85 1
88 HD 340611 WD* 20 34 21.8847019255 +25 03 49.750446346 10.687 11.471 11.546 11.648 11.728 DA2.4 329 0
89 MCT 2031-2745 WD* 20 34 54.5831600616 -27 34 49.200257388 13.61 14.81 15.28 15.53   DA.9 14 0
90 RX J2052.7+4639 WD* 20 52 43.8287290176 +46 39 34.876597068   17.7 17.50 17.1   DO 7 0
91 PG 2056+033 WD* 20 58 46.7372051784 +03 31 50.738069712   15.70   16.4   DA1.0 17 0
92 GD 394 WD* 21 12 44.0371201584 +50 06 17.887239540 11.70 12.85 13.09     DA1.3 188 1
93 MWP 1 PN 21 17 08.2817782392 +34 12 27.415995372   12.731 13.082 13.379   PG1159 199 0
94 MCT 2153-4156 WD* 21 56 35.3375767824 -41 42 17.711510868   15.593 15.815 15.3   DA 36 0
95 WG 39 WD* 21 57 38.3567715267 -51 00 31.521044535   14.94 14.73 14.53   DQ7 87 0
96 NGC 7293 PN 22 29 38.5454047152 -20 50 13.747242408 11.894 13.158 13.524 13.689 13.898 DAO.5 983 1
97 GD 246 WD* 23 12 21.6158334024 +10 47 04.257295476 11.578 12.772 13.090 13.238 13.418 DA.9 224 0
98 EC 23216-5458 WD* 23 24 30.8622650808 -54 41 35.509543332   14.91 15.13 15.72   DA1.1 58 0

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