J/ApJ/761/162 Tycho-2 stars in Galactic Bulge Survey (Hynes+, 2012)
Identification of Galactic Bulge Survey X-ray sources with Tycho-2 stars.
Hynes R.I., Wright N.J., Maccarone T.J., Jonker P.G., Greiss S.,
Steeghs D., Torres M.A.P., Britt C.T., Nelemans G.
<Astrophys. J., 761, 162 (2012)>
=2012ApJ...761..162H 2012ApJ...761..162H
ADC_Keywords: Spectral types ; Stars, variable ; Stars, distances ; Surveys ;
X-ray sources ; Cross identifications
Keywords: binaries: close; stars: activity; stars: emission-line, Be;
stars: massive; surveys
Abstract:
We identify 69 X-ray sources discovered by the Galactic Bulge Survey
(GBS) that are coincident with or very close to bright stars in the
Tycho-2 catalog. Additionally, two other GBS sources are resolved
binary companions to Tycho-2 stars where both components are
separately detected in X-rays. Most of these are likely to be real
matches, but we identify nine objects with large and significant
X-ray-to-optical offsets as either detections of resolved binary
companions or chance alignments. We collate known spectral types for
these objects, and also examine Two Micron All Sky Survey colors,
variability information from the All-Sky Automated Survey, and X-ray
hardness ratios for the brightest objects. Nearly a third of the stars
are found to be optically variable, divided roughly evenly between
irregular variations and periodic modulations. All fall among the
softest objects identified by the GBS. The sample forms a very mixed
selection, ranging in spectral class from O9 to M3. In some cases, the
X-ray emission appears consistent with normal coronal emission from
late-type stars, or wind emission from early-types, but the sample
also includes one known Algol, one W UMa system, two Be stars, and
several X-ray bright objects likely to be coronally active stars or
binaries. Surprisingly, a substantial fraction of the
spectroscopically classified, non-coincidental sample (12 out of 38
objects) have late B or A type counterparts. Many of these exhibit
redder near-IR colors than expected for their spectral type and/or
variability, and it is likely that the X-rays originate from a
late-type companion star in most or all of these objects.
Description:
Our starting point is the X-ray source lists from the Galactic Bulge
Survey (GBS). We merge the published list, which we will refer to as
the northern sample (Jonker et al. 2011, Cat. J/ApJS/194/18) with
additional sources detected in the final southern strip of the survey,
the southern sample (Jonker et al. 2014, Cat. J/ApJS/210/18). We
identify 70 Chandra sources that lie within 10 arcsec of 69 Tycho-2
(Hog et al. 2000, Cat. I/259) stars. Information about these matches
is summarized in Table 1 for the northern objects from Jonker et al.
and Table 2 for the southern objects from P. G. Jonker et al. Finally
we checked each matched Tycho-2 star against the All-Sky Automated
Survey (ASAS) Catalog of variable stars (Pojmanski 2002, Cat. II/264).
Our findings are summarized in Table 3.
In a few cases Hipparcos parallaxes exist for our optical counterparts
(van Leeuwen 2007, Cat. I/311). These provide good estimates of
distance, and hence X-ray luminosity (Table 4). In the absence of a
parallax distance, if we have a spectral and luminosity classification
then we can estimate a spectroscopic parallax distance (Table 5). See
section 6.1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 80 53 Bright optical counterparts to GBS Northern sources
table2.dat 76 16 Bright optical counterparts to GBS Southern Strip
sources
table3.dat 83 69 ASAS counterparts to optically bright GBS sources
table4.dat 116 8 Distances and luminosities based on Hipparcos
parallaxes
table5.dat 80 34 Distances and luminosities based on spectroscopic
parallaxes
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See also:
I/322 : UCAC4 Catalogue (Zacharias+, 2012)
III/265 : RAVE 3rd data release (Siebert+, 2011)
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
II/264 : ASAS Variable Stars in Southern hemisphere (Pojmanski+, 2002-2005)
IV/25 : HD identifications for Tycho-2 stars (Fabricius+, 2002)
I/276 : Tycho Double Star Catalogue (TDSC) (Fabricius+ 2002)
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
III/182 : HDE Charts: positions, proper motions (Nesterov+ 1995)
J/ApJS/210/18 : X-ray survey of the Galactic Bulge (CXOGBS) (Jonker+, 2014)
J/ApJS/194/18 : The Galactic Bulge Survey: X-ray observations (Jonker+, 2011)
J/ApJ/743/48 : Stellar rotation periods & X-ray luminosities (Wright+, 2011)
J/ApJ/725/480 : Stellar X-ray sources in the COSMOS survey (Wright+, 2010)
J/MNRAS/371/252 : Southern B and Be stars (Levenhagen+, 2006)
J/A+A/460/695 : Associations Containing Young stars (Torres+, 2006)
J/MNRAS/363/1111 : Tycho-2 stars with IR excess (Clarke+, 2005)
J/ApJ/595/1206 : ROSAT view of Hipparcos F stars (Suchkov+, 2003)
J/A+A/373/576 : Detection of Tycho variables stars (Piquard+, 2001)
J/A+A/368/835 : Galactic Center region soft X-ray sources (Sidoli+, 2001)
J/ApJ/315/687 : X-Ray emission from solar-type stars: F and G (Maggio+, 1987)
J/AJ/80/972 : Dwarf K and M stars at low latitudes (Stephenson+, 1975)
Byte-by-byte Description of file: table[12].dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- CX Source index number as in Jonker+, 2014,
Cat. J/ApJS/210/18 (04-1219 and B5-B422);
in Simbad
6- 17 A12 --- TYC Tycho-2 number (Cat. I/259)
19- 24 I6 --- HD ? HD identification
25 A1 --- m_HD HD multiplicity in case of binary
27- 30 F4.2 arcsec Sep [0/6.4] Offset between X-ray source and Tycho-2
32- 36 F5.2 mag Vmag [6.6/12.4] V-band magnitude
38- 41 F4.2 mag e_Vmag [0.01/0.4] Vmag uncertainty
43- 47 F5.2 mag (B-V) [-0.3/2] B-V color index
49- 52 F4.2 mag e_(B-V) [0.02/0.5] (B-V) uncertainty
54 A1 --- u_(B-V) [a] doubtful (B-V) (1)
56- 60 F5.2 --- logF [-5.4/-2.2] log(FX/Fopt)
62- 73 A12 --- SpT MK spectral type
75- 80 A6 --- Ref Reference(s) (2)
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Note (1): This color is almost certainly spurious due to strong variability in
this object.
Note (2): Reference as follows:
1 = Torres et al. 2006, Cat. J/A+A/460/695
2 = Steele et al. 1999A&AS..137..147S 1999A&AS..137..147S
3 = Lopes de Oliveira et al. 2006A&A...454..265L 2006A&A...454..265L
4 = Nesterov et al. 1995, Cat. III/182
5 = Siebert et al. 2011, Cat. III/265
6 = Houk 1982mcts.book.....H 1982mcts.book.....H
7 = Vijapurkar & Drilling 1993ApJS...89..293V 1993ApJS...89..293V
8 = Levenhagen & Leister 2006, Cat. J/MNRAS/371/252
9 = MacConnell & Bidelman 1976AJ.....81..225M 1976AJ.....81..225M
10 = Garrison et al. 1977ApJS...35..111G 1977ApJS...35..111G
12 = Parthasarathy et al. 2000A&AS..145..269P 2000A&AS..145..269P
13 = Raharto et al. 1984AnTok..19..469R 1984AnTok..19..469R
14 = Cannon & Mayall 1949, Cat. III/135, see also Cat. III/182
16 = Hoffleit 1956ApJ...124...61H 1956ApJ...124...61H
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- CX GBS source number
6- 18 A13 --- ASAS ASAS identifier (HHMMSS+DDMM.m; J2000; Cat. II/264)
20- 24 F5.3 mag Var [0.01/0.3] 68.2% variance of ASAS photometry
26- 36 F11.8 d Per [0.4/31.2]? Period
38- 47 F10.8 d e_Per ? Per uncertainty
49- 83 A35 --- Comm Comment
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- CX GBS source number
6- 11 A6 --- SpT MK spectral type
13- 17 F5.2 mag E(B-V) [-0.06/0.08] B-V color excess
19- 22 F4.2 mag e_E(B-V) [0.03/0.05] E(B-V) uncertainty
24- 28 F5.2 mas Plx [3.8/68] Hipparcos parallax
30- 34 F5.2 mas e_Plx [0.5/45] Plx uncertainty
36- 40 F5.1 pc Dist [15/260] Distance
42- 46 F5.1 pc E_Dist [1.5/170] Positive error on Dist
48- 51 F4.1 pc e_Dist [1.5/70] Negative error on Dist
53- 58 E6.2 10-7W LX X-ray luminosity
60- 66 E7.3 10-7W E_LX Positive error on LX
68- 73 E6.2 10-7W e_LX Negative error on LX
75-116 A42 --- Comm Comments
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Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- CX GBS source number
6- 18 A13 --- SpT MK spectral type
20- 24 F5.2 mag E(B-V) [-0.3/0.9] B-V inferred color excess
26- 29 F4.2 mag e_E(B-V) [0.02/0.3] E(B-V) uncertainty
30 A1 --- f_E(B-V) [b] Flag on E(B-V)
32- 35 F4.2 mag E(B-V)l [0.9/3.7] B-V line of sight color excess
37- 40 F4.2 mag e_E(B-V)l [0.2/0.5] E(B-V)l uncertainty
42- 45 I4 pc Dist [41/2800] Distance
47- 52 E6.2 10-7W LX X-ray luminosity
54- 80 A27 --- Comm Comments
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 25-Aug-2014