J/ApJS/178/339 ChaMP extended stellar survey (ChESS) (Covey+, 2008)
The ChaMP extended Stellar Survey (ChESS): photometric and spectroscopic
properties of serendipitously detected stellar X-ray sources.
Covey K.R., Agueros M.A., Green P.J., Haggard D., Barkhouse W.A., Drake J.,
Evans N., Kashyap V., Kim D.-W., Mossman A., Pease D.O., Silverman J.D.
<Astrophys. J. Suppl. Ser., 178, 339-358 (2008)>
=2008ApJS..178..339C 2008ApJS..178..339C
ADC_Keywords: X-ray sources ; Spectroscopy ; Surveys ; Photometry, SDSS
Photometry, infrared
Keywords: stars: activity - stars: chromospheres - stars: coronae
stars: flare - surveys - X-rays: stars
Abstract:
We present 348 X-ray-emitting stars identified from correlating the
Extended Chandra Multiwavelength Project (ChaMP), a wide-area
serendipitous survey based on archival X-ray images, with the Sloan
Digital Sky Survey (SDSS-DR6). We use morphological star/galaxy
separation, matching to an SDSS quasar catalog, an optical
color-magnitude cut, and X-ray data-quality tests to create our
catalog, the ChaMP Extended Stellar Survey (ChESS), from a sample of
2121 matched ChaMP/SDSS sources. Our cuts retain 92% of the
spectroscopically confirmed stars in the original sample while
excluding 99.6% of the 684 spectroscopically confirmed extragalactic
sources. Fewer than 3% of the sources in our final catalog are
previously identified stellar X-ray emitters. For 42 catalog members,
spectroscopic classifications are available in the literature. We
present new spectral classifications and Hα measurements for an
additional 79 stars. The catalog is dominated by main-sequence stars;
we estimate the fraction of giants in ChESS is ∼10%. We identify seven
giant stars (including a possible Cepheid and an RR Lyrae star) as
ChaMP sources, as well as three cataclysmic variables. Future papers
will present analyses of source variability and comparisons of this
catalog to models of stellar activity in the Galactic disk.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 120 348 ChaMP Stellar Catalog (X-rays)
table3.dat 134 360 ChaMP Stellar Catalog (Optical/IR)
table4.dat 33 82 ChaMP stars with spectra
table5.dat 70 66 ChaMP sources with SIMBAD counterparts
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-)
IX/29 : ROSAT All-Sky Survey Faint Source Catalog (Voges+ 2000)
II/282 : The SDSS Photometric Catalog, Release 6 (Adelman-McCarthy+, 2008)
J/ApJS/169/401 : ChaMP X-ray point source catalog (Kim+, 2007)
J/ApJS/150/19 : ChaMP. I. First X-ray source catalog (Kim+, 2004)
J/ApJ/596/944 : SEXSI catalog (Harrison+, 2003)
J/AJ/123/2223 : SPICES II: CHANDRA observations of Lynx (Stern+, 2002)
J/AJ/119/1901 : ROTSE all-sky surveys for variable stars (Akerlof+, 2000)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- CXOMP CXOMP identification (JHHMMSS.s+DDMMSS)
18- 19 A2 --- f_CXOMP [b-e, ] Flag(s) on CXOMP (1)
21- 24 I4 --- ObsID Chandra Obs. ID number (NNNN)
26- 30 F5.2 10-16W/m2 FBc Broadband 0.3-8.0keV X-ray flux (3)
32- 35 F4.2 10-16W/m2 e_FBc Uncertainty in FBc
37- 42 F6.1 ct NetBc Net broadband 0.3-8.0keV X-ray counts
44- 47 F4.1 ct e_NetBc Uncertainty in NetBc
49- 53 F5.2 10-16W/m2 FSc Soft 0.5-2.0keV X-ray flux (3)
55- 58 F4.2 10-16W/m2 e_FSc Uncertainty in FSc
60- 65 F6.1 ct NetSc Net soft 0.5-2.0keV X-ray counts
67- 70 F4.1 ct e_NetSc Uncertainty in NetSc
72- 76 F5.2 --- HR Hardness ratio (2)
78- 82 F5.2 [10-7W] logLXs Log of soft 0.5-2.0keV X-ray luminosity
84- 87 F4.2 [10-7W] e_logLXs Uncertainty in logLXs
89- 93 F5.2 [-] logXs/B Log of 0.5-2.0keV to Bolometric luminosities
95- 98 F4.2 [-] e_logXs/B Uncertainty in logXs/B
100-104 F5.2 [10-7W] logLXb Log of broadband 0.3-8.0keV X-ray luminosity
106-109 F4.2 [10-7W] e_logLXb Uncertainty in logLXb
111-115 F5.2 [-] logXb/B Log of 0.3-8.0keV to Bolometric luminosities
117-120 F4.2 [-] e_logXb/B Uncertainty in logXb/B
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Note (1): Flags as follows:
b = Sources more than 12arcmin from the Chandra optical axis. We have
conservatively increased their X-ray flux errors by 50%.
c = Sources on ACIS S4, which suffers from increased noise and streaking
relative to the other Chandra CCDs. We have conservatively increased
their X-ray flux errors by ∼20% to account for potential systematic
effects.
d = Sources which overlap other X-ray sources such that their positional
separation is less than the radius of the PSF width encircling 95% of
their flux. We have conservatively doubled their X-ray flux errors.
e = A strong extended X-ray source ∼30" distant may increase the flux
errors quoted here by up to ∼30%.
Note (2): where HR=(Hc-Sc)/(Hc+Sc) and Hc and Sc are the number of hard and
soft counts. Since we do not include any scientific results based on
HR, we simply characterize the typical errors here by noting that the
mean error on HR is well-fit for sources with HR>-0.98 by
HRerr=0.36(±0.027)*HR+0.40(±0.022), with RMS residuals of
σ=0.074. Sources with HR←0.98 have median HR errors of 0.106,
with RMS residuals of σ=0.073.
Note (3): in units of 10-13erg/cm2/s
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- CXOMP CXOMP identification (JHHMMSS.s+DDMMSS)
18- 21 F4.2 arcsec Sep SDSS/Chandra position separation
23- 27 F5.2 mag imag ? SDSS i band magnitude
29- 34 F6.2 mag e_imag ? Uncertainty in imag
36- 41 F6.2 mag u-g ? SDSS (u-g) color index
43- 48 F6.2 mag e_u-g ? Uncertainty in u-g
50- 54 F5.2 mag g-r ? SDSS (g-r) color index
56- 62 F7.2 mag e_g-r ? Uncertainty in g-r
64- 68 F5.2 mag r-i ? SDSS (r-i) color index
70- 75 F6.2 mag e_r-i ? Uncertainty in r-i
77- 81 F5.2 mag i-z ? SDSS (i-z) color index
83- 88 F6.2 mag e_i-z ? Uncertainty in i-z
90- 94 F5.2 mag sgmag ? Synthetic SDSS g band magnitude
96- 99 F4.2 mag e_sgmag ? Uncertainty in Syngmag
101 I1 --- SFlag SDSS saturation flag (1)
103-107 F5.2 mag Jmag ? 2MASS J band magnitude
109-112 F4.2 mag e_Jmag ? Uncertainty in Jmag
114-118 F5.2 mag J-H ? 2MASS (J-H) color index
120-123 F4.2 mag e_J-H ? Uncertainty in J-H
125-129 F5.2 mag H-Ks ? 2MASS (H-Ks) color index
131-134 F4.2 mag e_H-Ks ? Uncertainty in H-Ks
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Note (1): 0 = no, 1 or 2 = yes (see Section 5.3).
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- CXOMP CXOMP identification (JHHMMSS.s+DDMMSS)
18 A1 --- f_CXOMP [ab] CXOMP flag (1)
20- 21 A2 --- SpType MK Spectral Type
23- 27 F5.2 0.1nm EWHa Hα Equivalent Width
29- 33 F5.2 [-] log[LHa/Lbol] ?=- Log of Hα luminosity to
bolometric luminosity
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Note (1): Flags as follows:
a = counterpart is cataloged in Simbad but lacks a stellar type
b = counterpart is cataloged in Simbad and has a stellar type
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- CXOMP CXOMP identification (JHHMMSS.s+DDMMSS)
18- 20 A3 --- f_CXOMP [a-c, ] Flag(s) on CXOMP (1)
22- 45 A24 --- SName Simbad counterpart
47- 49 F3.1 arcsec Sep CXOMP/Simbad position separation
51- 55 F5.2 mag Bmag ?=- B band magnitude
57- 61 F5.2 mag Vmag ?=- V band magnitude
63- 68 A6 --- Com Spectral type or object type (2)
70 A1 --- f_Com [d] Comment for the TYC 3062-1317-1 object
type (3)
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Note (1): Flags as follows:
a = source cataloged in Stern et al., 2002, (Cat. J/AJ/123/2223)
b = source cataloged in Harrison et al., 2003, (Cat. J/ApJ/596/944)
c = source cataloged in VizieR, Cat. IX/29, (Voges et al., 2000)
Note (2): The double asterisks (**) indicate a double or multiple star,
"PM*" indicates a high proper motion stars, "RR*" a RR Lyrae-type
variable, and "Ce*" a Cepheid-type variable.
Note (3): While this star is classified as a Cepheid by Akerlof et al.
(2000, Cat. J/AJ/119/1901), inspection of the Northern Sky
Variability Survey (Wozniak et al., 2004AJ....127.2436W 2004AJ....127.2436W) light curve
for this object suggests that this is not a classical Cepheid.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 28-Jul-2009