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J/ApJ/673/331        X-ray observations of CG 12               (Getman+, 2008)

The stellar population and origin of the mysterious high-latitude star-forming cloud CG 12. Getman K.V., Feigelson E.D., Lawson W.A., Broos P.S., Garmire G.P. <Astrophys. J., 673, 331-353 (2008)> =2008ApJ...673..331G
ADC_Keywords: Clusters, open ; Globules ; X-ray sources ; Proper motions Keywords: H II regions - ISM: globules - open clusters and associations: individual (CG 12) - stars: formation - stars: pre-main sequence - X-rays: stars Abstract: The mysterious high Galactic latitude cometary globule CG 12 has been observed with the ACIS detector on board the Chandra X-Ray Observatory. We detect 128 X-ray sources, of which half are likely young stars formed within the globule's head. This new population of ≳50 T Tauri stars and one new embedded protostar is far larger than the previously reported few intermediate-mass and two protostellar members of the cloud. Description: The observations were obtained with the ACIS camera on board Chandra. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 111 128 Basic source properties table3.dat 107 45 X-ray spectroscopy for photometrically selected sources: thermal plasma fits table4.dat 153 128 Optical and NIR counterparts
See also: B/chandra : The Chandra Archive Log (CXC, 1999-) J/MNRAS/355/1272 : BVIJHKs photometry around CG 12 (Maheswar+, 2004) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 3 A3 --- Fld Chandra ACIS-I fields surveyed in the CG 12 region (G1) 5- 6 I2 --- Src X-ray source number within the field, [GFL2008] "Field" "Source" in Simbad 8- 25 A18 --- CXOU CXOUJ designation (HHMMSS.dd+DDMMSS.s) 27- 36 F10.6 deg RAdeg Right ascension in decimal degrees (J2000) 38- 47 F10.6 deg DEdeg Declination in decimal degrees (J2000) 49- 52 F4.2 arcsec e_Pos Positional uncertainty 54- 58 F5.2 arcmin Theta Off-axis angle 60- 64 F5.1 ct Fnet Estimated net counts from extracted area in total energy band 0.5-8.0keV 66- 69 F4.1 ct e_Fnet rms uncertainty on ctNetF 71- 74 F4.1 ct Fbg Estimated background counts from extracted area in total energy band 76- 80 F5.1 ct Hnet Estimated net counts from extracted area in hard energy band 2-8keV 82- 85 F4.2 --- Frac Fraction of the PSF at the fiducial energy of 1.497keV enclosed within the extracted area (2) 87- 90 F4.1 --- Signi Source significance in σ 92- 93 A2 --- Anom [ge ] Source anomalies (3) 95 A1 --- Var [abc] Variability characterization based on K-S statistics (4) 97-100 F4.1 ks Texp Source effective exposure 102-105 F4.2 keV Emed Background-corrected median photon energy in the total 0.5-8keV energy band 107-111 F5.2 [-] logPB Logarithm of K-S probability that background and source spectra are drawn from the same distribution (5)
Note (2): Note that a reduced PSF fraction (significantly below 90%) may indicate that the source is in a crowded region or on the edge of the field. Note (3): Source anomalies flags as follows: g = fractional time that source was on a detector (FRACEXPO from mkarf) is <0.9 e = source on field edge p = source piled up s = source on readout streak Note (4): Source variability flags as follows: a = no evidence for variability b = possibly variable c = definitely variable. blank = No test is performed for sources with fewer than 4 total full-band counts. No value is reported for sources in chip gaps or on field edges. Note (5): The value of logPB has been truncated at -4.0 for sources with significantly different background and source spectra.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 3 A3 --- Fld Chandra ACIS-I fields surveyed in the CG 12 region (G1) 5- 6 I2 --- Src X-ray source number within the field 8- 25 A18 --- CXOU CXOUJ designation (HHMMSS.dd+DDMMSS.s) 27- 31 F5.1 ct Fnet Estimated net counts from extracted area in total energy band 0.5-8.0keV 33- 36 F4.2 keV Emed Background-corrected median photon energy in the total 0.5-8keV energy band 38- 41 F4.1 [cm-2] logNH Best-fit value or the column density (1) 43- 45 F3.1 [cm-2] E_logNH ? Error on logNH (upper limit) 47- 49 F3.1 [cm-2] e_logNH ? Error on logNH (lower limit) 51- 55 F5.2 keV kT Best-fit value for plasma temperature (1) 56- 58 F3.1 keV E_kT ? Error on kT (upper limit) 60- 63 F4.1 keV e_kT ? Error on kT (lower limit) 65- 69 F5.2 [10-7W] logLh Hard band (2-8keV) X-ray luminosity (2) 71- 74 F4.2 [10-7W] e_logLh rms uncertainty on logLh 76- 80 F5.2 [10-7W] logLhc Hard band (2-8keV) absorption-corrected X-ray luminosity (2) 82- 85 F4.2 [10-7W] e_logLhc rms uncertainty on logLhc 87- 91 F5.2 [10-7W] logLt Total band (-0.5-8keV) X-ray luminosity (2) 93- 96 F4.2 [10-7W] e_logLt rms uncertainty on logLt 98-102 F5.2 [10-7W] logLtc Total band (-0.5-8keV) absorption-corrected X-ray luminosity (2) 104-107 F4.2 [10-7W] e_logLtc rms uncertainty on logLtc
Note (1): All fits used the "wabs(apec)" model in XSPEC and assumed 0.3Z abundances. 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 missing when XSPEC was unable to compute them or when their values were so large that the parameter is effectively unconstrained. Fitted values with logNH<20.0cm-2 are truncated at 20.0 because ACIS-I spectra are insensitive to differences in very low column densities. Fitted values with kT>15keV are truncated at 15keV because the data often cannot discriminate between very high temperature values. Note (2): X-ray luminosities are calculated assuming a distance of 550pc
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 3 A3 --- Fld Chandra ACIS-I fields surveyed in the CG 12 region (G1) 5- 6 I2 --- Src X-ray source number within the field 8- 25 A18 --- CXOU CXOUJ designation (HHMMSS.dd+DDMMSS.s) 27- 38 A12 --- NOMAD NOMAD identifier (NNNN-NNNNNNN) 40- 42 F3.1 arcsec Sep1 ? Chandra-NOMAD positional offset 44- 48 A5 --- [MMB2004b] Source identifier from Maheswar et al. (2004, Cat. J/MNRAS/355/1272) 50- 54 F5.2 mag Vmag ? V magnitude (1) 56- 59 F4.2 mag e_Vmag ? rms uncertainty on Vmag 61- 65 F5.2 mag Rmag ? R magnitude (1) 67- 70 F4.2 mag e_Rmag ? rms uncertainty on Rmag 72- 76 F5.1 mas/yr pmRA ? Best proper motion along RA (pmRA*cosDE) (2) 78- 81 F4.1 mas/yr e_pmRA ? rms uncertainty on pmRA 83- 87 F5.1 mas/yr pmDE ? Best proper motion along DE (2) 89- 92 F4.1 mas/yr e_pmDE ? rms uncertainty on pmDE 94-109 A16 --- 2MASS 2MASS designation (HHMMSSss+DDMMSSs) 111-113 F3.1 arcsec Sep2 ? Chandra-2MASS positional offset 115-119 F5.2 mag Jmag ? 2MASS J magnitude 121-124 F4.2 mag e_Jmag ? rms uncertainty on Jmag 126-130 F5.2 mag Hmag ? 2MASS H magnitude 132-135 F4.2 mag e_Hmag ? rms uncertainty on Hmag 137-141 F5.2 mag Ksmag ? 2MASS Ks magnitude 143-146 F4.2 mag e_Ksmag ? rms uncertainty on Ksmag 148-153 A6 --- Flags 2MASS photometry quality and confusion-contamination flag
Note (1): When formal statistical errors are given, V and R magnitudes are from Maheswar et al. (2004, Cat. J/MNRAS/355/1272). V magnitudes for three B-type stars, I 57, I 58, and I 74, are from Williams et al. (1977MNRAS.180..709W). Otherwise, V and R magnitudes are from the NOMAD catalog, in which case all V magnitudes except for the Chandra source I 81 are from the YB6 (=USNO unpublished) catalog, and all R magnitudes except for the Chandra source I 57 are from the USNO-B1.0 catalog (R magnitudes from USNO-B1.0 are second red magnitudes R2, except for the Chandra sources I 70 and II 9, for which it is a first red magnitude R1). For the Chandra source I 81 V magnitude is from the Tycho-2 catalog, and for the Chandra source I 57 R magnitude is from the UCAC2 catalog. Note (2): "Best" proper motions and their mean errors from catalogs compiled in NOMAD (Cat. I/297)
Global notes: Note (G1): I-primary pointing; II, III, and IV-secondary pointings. Table1 : CG 12 Observations ------------------------------------------------------------------------------- Field ObsID Start Time Exp RA (J2000.0) DE Roll Angle (UT) (ks) (deg) ------------------------------------------------------------------------------- I 6423 2006/04/15 16:19:17 30.8 13 57 44.52 -39 58 48.31 11.5 II 6424 2006/06/02 07:25:09 3.1 13 57 42.87 -39 43 01.76 285.0 III 6425 2006/04/13 08:44:08 3.1 13 56 19.40 -39 42 47.94 14.7 IV 6426 2006/04/15 12:54:20 3.1 13 56 19.40 -39 58 48.09 11.1
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 08-Apr-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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