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J/ApJ/685/463    ChaMPlane X-ray sources in the Galactic bulge   (Koenig+, 2008)

Investigating ChaMPlane X-ray sources in the Galactic bulge with Magellan LDSS2 spectra. Koenig X., Grindlay J.E., van den Berg M., Laycock S., Zhao P., Hong J., Schlegel E.M. <Astrophys. J., 685, 463-477 (2008)> =2008ApJ...685..463K
ADC_Keywords: Photometry, VRI ; Spectral types ; Surveys ; X-ray sources ; Stars, dwarfs Keywords: Galaxy: stellar content - novae, cataclysmic variables - stars: activity - stars: late-type - surveys - X-rays: stars Abstract: We have carried out optical and X-ray spectral analyses on a sample of 136 candidate optical counterparts of X-ray sources found in five Galactic bulge fields included in our Chandra Multiwavelength Plane Survey. We use a combination of optical spectral fitting and quantile X-ray analysis to obtain the hydrogen column density toward each object, and a three-dimensional dust model of the Galaxy to estimate the most probable distance in each case. We present the discovery of a population of stellar coronal emission sources, likely consisting of pre-main-sequence, young main-sequence, and main-sequence stars, as well as a component of active binaries of RS CVn or BY Dra type. We identify one candidate quiescent low-mass X-ray binary with a subgiant companion; we note that this object may also be an RS CVn system. We report the discovery of three new X-ray-detected cataclysmic variables (CVs) in the direction of the Galactic center (at distances ≲2kpc). This number is in excess of predictions made with a simple CV model based on a local CV space density of ≲10-5pc-3, and a scale height ∼200pc. We discuss several possible reasons for this observed excess. Description: X-ray data for this paper come from three ACIS-I and one ACIS-S Chandra pointings use in the ChaMPlane survey (Hong et al., 2005ApJ...635..907H). Targets for optical spectral follow-up were selected following observations made in 2000 March with the Mosaic camera on the CTIO 4m telescope in V,R,I, and Hα filters to identify candidate counterparts. The target list was used for the observing runs in 2001-2002 with the Low Dispersion Survey Spectrograph 2 (LDSS2) on the 6.5m Baade Magellan telescope. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table5.dat 134 136 Combined results for 2σ optical matches
See also: B/cb : Cataclysmic Binaries, LMXBs, and related objects (Ritter+, 2010) : ChaMPlane survey home page Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 5 A5 --- Field Field identification 7- 25 A19 --- ChOPS ChOPS identification: (1) 27- 40 A14 --- SpType Spectral type classification (2) 42- 43 A2 --- Class Special source classification type (3) 45- 48 I4 ct Cts Background subtracted 0.3-0.8keV net counts 50 A1 --- f_Cts [*] * for source with SNR<3 52- 53 I2 ct e_Cts Uncertainty in Cts 55 A1 --- l_NH Limit flag on NH 56- 61 F6.3 10+22/cm2 NH Hydrogen column density from spectral fit (4) 63 A1 --- f_NH [d] NH estimated from QCCD analysis (5) 65- 66 I2 10+21/cm2 e_NH ? Uncertainty in NH 68 A1 --- l_X/R Limit flag on Fx/FR 69- 72 F4.1 [-] X/R ? log(Fx/Fr) of unabsorbed 0.5-2keV X-ray to unreddened R band flux (in ergs/cm2/s/100nm) 74- 76 F3.1 [-] e_X/R ? Uncertainty in Fx/FR 78 A1 --- l_Dist Limit flag on Dist 79- 82 F4.1 kpc Dist ? Heliocentric distance; error about 60% 84 A1 --- l_VMAG Limit flag on VMAG 85- 90 F6.2 mag VMAG ? Absolute V band magnitude 92- 93 I2 dmag e_VMAG ? Uncertainty in VMag (in 0.1mag) 95 A1 --- l_logLx Limit on logLx 97-101 F5.2 [10-7W] logLx ? Log of 0.5-2keV X-ray luminosity 103-105 F3.1 [10-7W] e_logLx ? Uncertainty in logLx 107-112 F6.3 mag Rmag R band magnitude 114 I1 cmag e_Rmag Uncertainty in Rmag (in 0.01mag) 116 I1 --- Nm Number of optical matches (6) 118-122 F5.3 arcsec Srch Combined 95% X-ray and optical position error circle (7) 124-128 F5.3 arcsec off Positional offset between X-ray and optical position 130-134 F5.3 --- PRn Random match probability (8)
Note (1): ChaMPlane IDs have prefix ChOPS (<ChOPS> in Simbad). Note (2): Spectral type classifications: MidM = M4-M6 spectral range, with Teff=3000±500K, MV=13.2±2.0 LateG = G6-G8 spectral range, with Teff=5200±500K, MV=5.3±0.5 MidG = G4-G6 spectral range, with Teff=5400±500K, MV=4.9±0.5 EarlyG = G2-G4 spectral range, with Teff=5600±500K, MV=4.6±0.4 F/G = F8-G2 spectral range, with Teff=5950±500K, MV=4.3±0.7 LateF = F6-F8 spectral range, with Teff=6200±500K, MV=3.8±0.4 EarlyA = A2-A4 spectral range, with Teff=9100±500K, MV=1.8±0.4 See Table 4 of paper for further details of spectral type classification. Note (3): Object classification for 19 special sources as follows: q = qLMXB (quiescent low-mass X-ray binary system) candidate; by = BY Dra candidate; rs = RS CVn candidate; tt = T Tauri; cv = Cataclysmic Variable. Note (4): True value may be higher by ∼0.2, see text. Note (5): Objects with "?" spectral type and CVs, which have NH estimated from X-ray quantile color-color diagram (QCCD) analysis. Note (6): Found within 95% confidence (2σ) error circle of this X-ray source. Note (7): Used to search for optical matches. Note (8): Given error circle size and measured local optical projected surface density.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 13-Dec-2010
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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