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J/ApJS/194/15       CCCP: Carina's diffuse X-ray emission      (Townsley+, 2011)

The Chandra Carina Complex Project: deciphering the enigma of Carina's diffuse X-ray emission. Townsley L.K., Broos P.S., Chu Y.-H., Gagne M., Garmire G.P., Gruendl R.A., Hamaguchi K., Mac Low M.-M., Montmerle T., Naze Y., Oey M.S., Park S., Petre R., Pittard J.M. <Astrophys. J. Suppl. Ser., 194, 15 (2011)> =2011ApJS..194...15T
ADC_Keywords: Abundances ; X-ray sources ; Interstellar medium ; Models Keywords: H II regions - stars: massive - stars: winds - outflows - X-rays: individual (Carina) - X-rays: ISM - X-rays: stars Abstract: We present a 1.42deg2 mosaic of diffuse X-ray emission in the Great Nebula in Carina from the Chandra X-ray Observatory Advanced CCD Imaging Spectrometer camera. After removing >14000 X-ray point sources from the field, we smooth the remaining unresolved emission, tessellate it into segments of similar apparent surface brightness, and perform X-ray spectral fitting on those tessellates to infer the intrinsic properties of the X-ray-emitting plasma. By modeling faint resolved point sources, we estimate the contribution to the extended X-ray emission from unresolved point sources and show that the vast majority of Carina's unresolved X-ray emission is truly diffuse. Line-like correlated residuals in the X-ray spectral fits suggest that substantial X-ray emission is generated by charge exchange at the interfaces between Carina's hot, rarefied plasma and its many cold neutral pillars, ridges, and clumps. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 77 161 Tessellate properties table3.dat 221 161 Spectral fits for diffuse tesselates
See also: J/ApJS/194/2 : Chandra Carina Complex Project (CCCP) catalog (Broos+, 2011) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 10 A10 --- Name Diffuse region label (in/outsideNNN) 12- 21 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000) 23- 32 F10.6 deg DEdeg Declination in decimal degrees (J2000) 34- 38 F5.1 arcmin2 Area Geometric area of tessellate (1) 40- 44 I5 ct Ct Net 0.5-7keV extracted counts (2) 46- 49 F4.1 ph/Ms/cm2/arcmin2 Flux Photon surface flux (3) 51- 77 A27 --- Note Additional notes
Note (1): Irrespective of point source masking. Note (2): Less counts expected from instrumental background. Note (3): In 10-6ph/s/cm2/arcmin2. A quantity that accounts for calibration details such that it can be used to compare the apparent diffuse emission between tesselates; larger values imply brighter tesselates.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 10 A10 --- Name Diffuse region label (in/outsideNNN) 12- 15 F4.1 pc2 Apc Geometric area of tessellate (4) 17- 20 F4.1 [cm-2] logNH1 log(H column density) of component#1 (5) 22- 25 F4.2 [cm-2] e_logNH1 ? Lower limit uncertainty in logNH1 (5) 27- 30 F4.2 [cm-2] E_logNH1 ? Upper limit uncertainty in logNH1 (5) 32- 35 F4.1 [cm-2] logNH2 log(H column density) of component#2 (5) 37- 40 F4.2 [cm-2] e_logNH2 ? Lower limit uncertainty in logNH2 (5) 42- 45 F4.2 [cm-2] E_logNH2 ? Upper limit uncertainty in logNH2 (5) 47- 50 F4.1 [cm-2] logNH3 log(H column density) of component#3 (5) 52- 55 F4.2 [cm-2] e_logNH3 ? Lower limit uncertainty in logNH3 (5) 57- 60 F4.2 [cm-2] E_logNH3 ? Upper limit uncertainty in logNH3 (5) 62- 65 F4.2 keV kT1 Plasma temperature of component#1 (5) 67- 70 F4.2 keV e_kT1 ? Lower limit uncertainty in kT1 (5) 72- 75 F4.2 keV E_kT1 ? Upper limit uncertainty in kT1 (5) 77- 80 F4.2 keV kT2 Plasma temperature of component#2 (5) 82- 85 F4.2 keV e_kT2 ? Lower limit uncertainty in kT2 (5) 87- 90 F4.2 keV E_kT2 ? Upper limit uncertainty in kT2 (5) 92- 95 F4.2 keV kT3 Plasma temperature of component#3 (5) 97-100 F4.2 keV e_kT3 ? Lower limit uncertainty in kT3 (5) 102-105 F4.2 keV E_kT3 ? Upper limit uncertainty in kT3 (5) 107-111 F5.2 [cm-3.s] logt1 log(plasma ionization timescale), comp.#1 (5) 113-116 F4.2 [cm-3.s] logt2 log(plasma ionization timescale), comp.#2 (5) 118-122 F5.2 [cm-3.s] logt3 log(plasma ionization timescale), comp.#3 (5) 124-127 F4.1 [cm-3/pc2] logS1 log(surface emission measure), comp.#1 (5) 129-132 F4.2 [cm-3/pc2] e_logS1 ? Lower limit uncertainty in logS1 (5) 134-137 F4.2 [cm-3/pc2] E_logS1 ? Upper limit uncertainty in logS1 (5) 139-142 F4.1 [cm-3/pc2] logS2 log(surface emission measure), comp.#2 (5) 144-147 F4.2 [cm-3/pc2] e_logS2 ? Lower limit uncertainty in logS2 (5) 149-152 F4.2 [cm-3/pc2] E_logS2 ? Upper limit uncertainty in logS2 (5) 154-157 F4.1 [cm-3/pc2] logS3 log(surface emission measure), comp.#3 (5) 159-162 F4.2 [cm-3/pc2] e_logS3 ? Lower limit uncertainty in logS3 (5) 164-167 F4.2 [cm-3/pc2] E_logS3 ? Upper limit uncertainty in logS3 (5) 169-171 F3.1 Sun Si ? The Si abundance; solar units (5) 173-176 F4.2 Sun e_Si ? Lower limit uncertainty in Si (5) 178-181 F4.2 Sun E_Si ? Upper limit uncertainty in Si (5) 183-185 F3.1 Sun Fe ? The Fe abundance; solar units (5) 187-190 F4.2 Sun e_Fe ? Lower limit uncertainty in Fe (5) 192-195 F4.2 Sun E_Fe ? Upper limit uncertainty in Fe (5) 197-199 I3 --- chi2 Model χ2 201-203 I3 --- dof Model degrees of freedom 205-209 F5.2 [10-7W/pc2] logSB1 log(surface brightness), comp.#1 (6) 211-215 F5.2 [10-7W/pc2] logSB2 log(surface brightness), comp.#2 (6) 217-221 F5.2 [10-7W/pc2] logSB3 log(surface brightness), comp.#3 (6)
Note (4): Irrespective of point source masking. Note (5): All fits used the source model "TBabs*vpshock + TBabs*vpshock + TBabs*vpshock + TBabs*apec + TBabs*apec + TBabs*apec" in XSPEC. * NH. are the best-fit value for the extinction column densities (TBabs components). * kT. are the best-fit value for the plasma temperatures (vpshock components). * t. are the electron-density-weighted ionization timescales for the plasma (vpshock components). * S. are the "surface emission measure" (X-ray emission measure per unit area) for the plasmas (vpshock components), assuming a distance of 2.3kpc. * Abundances in the plasma models were tied together. * Abundances of He, C, N, Al, Ar, and Ca were frozen at 1.0Z. * Abundances of Si and Fe are reported in the table and when omitted the abundance was frozen at 1.0Z. * The Ni abundance was tied to Fe. * Abundances of O, Ne, Mg, and S have values greater than solar in some fits but those values are not well-constrained so they are not reported here. Uncertainties represent 90% confidence intervals. More significant digits are used for uncertainties <0.1 in order to avoid large rounding errors; for consistency, the same number of significant digits is used for both lower and upper uncertainties. Uncertainties are blank when XSPEC was unable to compute them or when their values were so large that the parameter is effectively unconstrained. Note (6): Absorption-corrected surface brightness of the diffuse emission in Carina (vpshock components) in the total band (0.5-7keV), assuming a distance of 2.3kpc. In units of erg/s/pc2.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 27-May-2011
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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