J/A+A/539/A74 NGC1893 Chandra X-ray catalog (Caramazza+, 2012)
Star formation in the outer Galaxy: coronal properties of NGC 1893.
Caramazza M., Micela G., Prisinzano L., Sciortino S., Damiani F., Favata F.,
Stauffer J.R., Vallenari A., Wolk S.J.
<Astron. Astrophys. 539, A74 (2012)>
=2012A&A...539A..74C 2012A&A...539A..74C
ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; X-ray sources
Keywords: stars: pre-main sequence - stars: luminosity function, mass function -
X-rays: stars - stars: coronae - stars: flare -
open clusters and associations: individual : NGC 1893
Abstract:
The outer Galaxy, where the environmental conditions are different
from the solar neighbourhood is a laboratory in which it is possible
to investigate the dependence of star formation process on the
environmental parameters.
We investigate the X-ray properties of NGC 1893, a young cluster
(∼1-2Myr) in the outer part of the Galaxy (galactic radius ≥11kpc)
where we expect differences in the disk evolution and in the mass
distribution of the stars, to explore the X-ray emission of its
members and compare it with that of young stars in star forming
regions near to the Sun.
Description:
We analyze 5 deep Chandra ACIS-I observations with a total exposure
time of 450ks. Source events of the 1021 X-ray sources have been
extracted with the IDL-based routine ACIS-Extract. Using spectral
fitting and quantile analysis of X-ray spectra, we derive X-ray
luminosities and compare the respective properties of Class II and
Class III members. We also evaluate the variability of sources using
the Kolmogorov-Smirnov test and we identify flares in the lightcurves.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 122 1021 NGC1893 Chandra X-ray catalog:
basic source properties
uplimit.dat 34 158 Upper limit to the X-ray luminosities for
NGC1893 X-ray undetected members
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See also:
J/A+A/527/A77 : NGC 1893 optical and NIR photometry (Prisinzano+, 2011)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq Identification number
6- 23 A18 --- Name IAU Designation (HHMMSS.ss+DDMMSS.s)
25- 33 F9.6 deg RAdeg X-ray Right ascension (J2000)
36- 45 F10.6 deg DEdeg X-ray Declination (J2000)
49- 51 F3.1 arcsec e_pos Standard deviation of position
54- 57 F4.1 arcmin OffAxis Off-axis angle
60- 65 F6.1 ct CTn Net counts extracted in the total energy band
68- 71 F4.1 ct e_CTn Average of the upper and lower 1 sigma errors
75- 79 F5.1 ct CTbg Background counts expected in the source
extraction region (total band)
82- 85 F4.2 --- PSFf [0/1] Fraction of the PSF (at 1.497keV)
enclosed within the extraction region
89- 92 F4.1 --- Signi Photometric significance computed as net
counts divided by the upper error on net
counts
95-100 F6.4 --- PKS [0/1]? Kolmogorov-Smirnov probability that
the lightcurves of the sources are constant
103-107 F5.1 ks t.exp Effective exposure time
110-112 F3.1 keV Emed ? Background-corrected median photon energy
(total band)
115-119 F5.2 [10-7W] logLX ? Absorption-corrected X-ray luminosities
122 A1 --- r_logLX ? X-ray Luminosity origin (1)
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Note (1): Origin of the X-ray luminosity as follows:
a = from fit to a one temperature model spectrum
b = from analysis of quantiles
c = from a conversion factor derived from the analysis of the quantiles
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Byte-by-byte Description of file: uplimit.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID Prisinzano et al. (2011, Cat. J/A+A/527/A77)
identification number
8- 16 F9.6 deg RAdeg Right ascension (J2000)
19- 28 F10.6 deg DEdeg Declination (J2000)
30- 34 F5.2 [10-7W] logTX Estimated upper limit to the
absorption-corrected X-ray luminosities
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Acknowledgements:
Marilena Caramazza, mcarama(at)astropa.unipa.it
(End) Marilena Caramazza [INAF-OAPA, Italy], Patricia Vannier [CDS] 15-Dec-2011