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J/ApJ/613/1179         X-ray sources in Galactic Center            (Muno+, 2004)

The spectra and variability of X-ray sources in a deep Chandra observation of the Galactic Center. Muno M.P., Arabadjis J.S., Baganoff F.K., Bautz M.W., Brandt W.N., Broos P.S., Feigelson E.D., Garmire G.P., Morris M.R., Ricker G.R. <Astrophys. J., 613, 1179-1201 (2004)> =2004ApJ...613.1179M
ADC_Keywords: X-ray sources ; Spectroscopy Mission_Name: Chandra Keywords: binaries: general - Galaxy: center - novae, cataclysmic variables - X-rays: binaries - X-rays: stars Abstract: We examine the X-ray spectra and variability of the sample of X-ray sources with LX∼1031-1033ergs/s identified within the inner 9' of the Galaxy by Muno et al. Very few of the sources exhibit intraday or intermonth variations. Description: Twelve separate pointings toward the Galactic center have been carried out using the Advanced CCD Imaging Spectrometer imaging array (ACIS-I) on board the Chandra X-Ray Observatory in order to monitor Sgr A*. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 152 566 Spectra of Individual Point Sources table3.dat 137 64 Iron emission from sources with more than 160 net counts table6.dat 71 44 Sources with short-term variability table7.dat 60 75 Sources with long-term variability
See also: B/chandra : The Chandra Archive Log (CXC, 2002-) J/ApJ/589/225 : Chandra X-ray sources toward Galactic Center (Feigelson+ 2003) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 16 A16 --- CXOGC IAU Designation 18- 21 I4 ct cts Net counts, 0.5-8.0keV 23 A1 --- l_PNH [<>e] Limit flag on PNH (1) 25- 29 F5.1 10+22/cm2 PNH Absorption, power component 31- 35 F5.1 10+22/cm2 PNHl Lower value of PNH interval 37- 41 F5.1 10+22/cm2 PNHh Upper value of PNH interval 43 A1 --- l_Gamma [<>e] Limit flag on Gamma (1) 45- 48 F4.1 --- Gamma Power-law photon index Γ 50- 53 F4.1 --- Gammal Lower value of Γ interval 55- 58 F4.1 --- Gammah Upper value of Γ interval 60- 64 F5.2 10-17W/m2 Pflux Power law flux (2) 66- 72 F7.2 10-17W/m2 uPflux De-absorbed power-law flux (2) 74- 77 I4 --- Pchi2 Chi-squared for power-law fit 79- 82 I4 --- d_Pchi2 Degrees of freedom for Pchi2 84 A1 --- l_TNH [<>e] Limit flag for TNH (1) 86- 90 F5.1 10+22/cm2 TNH Absorption for plasma model 92- 96 F5.1 10+22/cm2 TNHl Lower value of TNH interval 98-102 F5.1 10+22/cm2 TNHh Upper value of TNH interval 104 A1 --- l_kT [<>e] Limit flag for kT (1) 106-109 F4.1 keV kT Plasma temperature 111-114 F4.1 keV kTl Lower value of kT interval 116-119 F4.1 keV kTh Upper value of kT interval 121-125 F5.2 10-17W/m2 Tflux Plasma model flux (2) 127-133 F7.2 10-17W/m2 uTflux De-absorbed plasma model flux (2) 135-138 I4 --- Tchi2 Plasma model chi-squared 140-143 I4 --- d_Tchi2 Degrees of freedom for Tchi2 145 A1 --- f6.4 [yn-] Whether 6.4 keV Fe is detected 148 A1 --- f6.7 [yn-] Whether 6.7 keV Fe is detected 150-152 A3 --- Flags Flag for quality of spectrum (3)
Note (1): The limit flag has the following meaning: > = a lower limit, < = an upper limit, e = the uncertainty calculation failed to converge. If the flag is set, the lower and upper uncertainties will be 0. Note (2): In units of 10-14erg/cm2/s. Note (3): Flags for the quality of the spectrum are defined as follows: l = long-term variability; s = short-term variability; e = lies near the edge of the CCD; c = may be blended with a nearby source.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 16 A16 --- CXOGC IAU Designation 19- 22 F4.1 --- G6.4 Power-law photon index for low-ionization Fe (6.4keV) 24- 26 F3.1 --- E_G6.4 Upper error limit on G6.4keV 28- 30 F3.1 --- e_G6.4 Lower error limit on G6.4keV 33 A1 --- l_F(6.4) Limit flag on F(6.4) 34- 37 F4.1 ct/m2/ks F(6.4) ? Flux at 6.4keV (G1) 39- 41 F3.1 ct/m2/ks E_F(6.4) ? Upper error limit on F(6.4) 43- 45 F3.1 ct/m2/ks e_F(6.4) ? Lower error limit on F(6.4) 47 A1 --- l_EW(6.4) Limit flag on EW(6.4) 48- 52 I5 eV EW(6.4) ? Equivalent width for low-ionization Fe 56- 59 F4.1 --- Dchi2(6.4) ? Delta(chi2) for low-ionization Fe (1) 62- 66 F5.3 --- P(6.4) ? Probability for low-ionization Fe (2) 69- 77 A9 --- chi2(6.4) Reduced chi-squared (χ2/dof) 79- 82 F4.1 --- G6.7 Power-law photon index for He-like Fe (6.7keV) 84- 86 F3.1 --- E_G6.7 Upper error limit on G6.7 88- 90 F3.1 --- e_G6.7 Lower limit error on G6.7keV 93 A1 --- l_F(6.7) Limit flag on F(6.7) 94- 97 F4.1 ct/m2/ks F(6.7) ? Flux at 6.7keV (G1) 99-101 F3.1 ct/m2/ks E_F(6.7) ? Upper error limit on F(6.7) 103-105 F3.1 ct/m2/ks e_F(6.7) ? Lower error limit on F(6.7) 108 A1 --- l_EW(6.7) Limit flag on EW(6.7) 109-113 I5 eV EW(6.7) ? Equivalent width for He-like Fe 116-119 F4.1 --- Dchi2(6.7) ? Delta(chi2) for He-like Fe (1) 122-126 F5.3 --- P(6.7) ? Probability for He-like Fe (2) 129-137 A9 --- chi2(6.7) Reduced chi-squared (χ2/dof)
Note (1): Difference of chi-squared with and without the line Note (2): PFe refers to the chance probability that the line emission could be produced by random variations in a featureless continuum. Only sources with PFe<0.01 for a line at either 6.4 or 6.7keV are listed in the table. Note that the line emission for those sources with a best-fit power laws with Γ>4 should be viewed extremely skeptically, because these steep spectra are background-dominated above 6keV.
Byte-by-byte Description of file: table6.dat
Bytes Format Units Label Explanations
1- 16 A16 --- CXOGC IAU designation 17 A1 --- f_CXOGC [b] Flag on CXOGC (1) 19- 20 A2 --- fg [GC F] Location in the foreground of or near the Galactic Center 23- 26 I4 --- ObsID Observation identification 27 A1 --- f_ObsID Flag on ObsID 30- 34 A5 --- Var Variability type (2) 37- 40 F4.1 ks Deltat ? Time interval 43 A1 --- l_Fmin ? Limit flag on Fmin 44- 46 I3 ct/m2/ks Fmin ? Minimum flux (G1) 48- 49 I2 ct/m2/ks E_Fmin ? Upper error limit on Fmin 51- 52 I2 ct/m2/ks e_Fmin ? Lower error limit on Fmin 55- 58 I4 ct/m2/ks Fmax ? Maximum flux (G1) 59 A1 --- f_Fmax Flag on Fmax (3) 60- 62 I3 ct/m2/ks E_Fmax ? Upper error limit on Fmax 64- 66 I3 ct/m2/ks e_Fmax ? Lower error limit on Fmax 69 A1 --- l_FR Limit flag on Fmax/Fmin ratio 70- 71 I2 --- FR ? Ratio Fmax/Fmin
Note (1): The variability from these sources was identified via the K-S test (Kolmogorov-Smirnov test), but not by the Bayesian blocks algorithm. Note (2): If the Bayesian blocks code identified only two intervals with differing count rates, then the variability was classified as a "step" function. If it identified more than two intervals with differing count rates, we defined the variability as a flare Note (3): A "c" indicates that this flare consisted of five photons received within 100s.
Byte-by-byte Description of file: table7.dat
Bytes Format Units Label Explanations
1- 16 A16 --- CXOGC IAU Designation 19- 20 A2 --- fg [GC F] Location in the foreground of or near the Galactic Center 23- 26 I4 --- ObsIDmin ObsID of Minimum 27 A1 --- f_ObsIDmin Flag on ObsIDmin 30 A1 --- l_Fmin Limit flag on Fmin 31- 32 I2 ct/m2/ks Fmin Minimum flux (G1) 34- 35 I2 ct/m2/ks E_Fmin ? Upper error limit on Fmin 37- 38 I2 ct/m2/ks e_Fmin ? Lower error limit on Fmin 41- 44 I4 --- ObsIDmax ObsID of Maximum 45 A1 --- f_ObsIDmax Flag on ObsIDmax 47- 49 I3 ct/m2/ks Fmax Maximum flux (G1) 51- 52 I2 ct/m2/ks E_Fmax Upper error limit on Fmax 54- 55 I2 ct/m2/ks e_Fmax Lower limit error on Fmax 58 A1 --- l_FR Limit flag on Fmax/Fmin ratio 59- 60 I2 --- FR Ratio Fmax/Fmin
Global notes: Note (G1): count rate expressed in units of 10-7photons/cm2/s
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 09-Jun-2005
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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