J/ApJS/194/4 Classification of CCCP X-ray sources (Broos+, 2011)
A Naive Bayes source classifier for X-ray sources.
Broos P.S., Getman K.V., Povich M.S., Townsley L.K., Feigelson E.D.,
Garmire G.P.
<Astrophys. J. Suppl. Ser., 194, 4 (2011)>
=2011ApJS..194....4B 2011ApJS..194....4B
ADC_Keywords: X-ray sources ; Surveys ; Nebulae ; Associations, stellar
Keywords: methods: data analysis - methods: statistical -
stars: pre-main sequence - X-rays: general - X-rays: stars
Abstract:
The Chandra Carina Complex Project (CCCP) provides a sensitive X-ray
survey of a nearby starburst region over >1deg2 in extent. Thousands
of faint X-ray sources are found, many concentrated into rich young
stellar clusters. However, significant contamination from unrelated
Galactic and extragalactic sources is present in the X-ray catalog. We
describe the use of a Naive Bayes classifier to assign membership
probabilities to individual sources, based on source location, X-ray
properties, and visual/infrared properties. For the particular
membership decision rule adopted, 75% of CCCP sources are classified
as members, 11% are classified as contaminants, and 14% remain
unclassified. The resulting sample of stars likely to be Carina
members is used in several other studies, which appear in this special
issue devoted to the CCCP.
Description:
Broos et al. (2011, Cat. J/ApJS/194/2) and citations therein describe
the X-ray, visual, NIR, and MIR measurements available for CCCP
sources.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 94 14368 Classification quantities for CCCP sources
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See also:
J/ApJS/194/2 : Chandra Carina Complex Project (CCCP) catalog (Broos+, 2011)
http://en.wikipedia.org/wiki/Naive_Bayes_classifier : Naive Bayes classifier
definition
http://cxc.harvard.edu/ciao/caveats/psf_artifact.html : about Chandra PSF
Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- CXOGNC CCCP name (HHMMSS.ss+DDMMSS.s format) (1)
20- 23 F4.2 --- H1-Pr H1 (foreground*) prior class probability
25- 28 F4.2 --- H2-Pr H2 (Car YSO) prior class probability
30- 33 F4.2 --- H3-Pr H3 (background*) prior class probability
35- 38 F4.2 --- H4-Pr H4 (extragalactic) prior class probability
40- 44 F5.2 --- H1-Pst ?=-9.9 H1 (foreground*) posterior probability
46- 50 F5.2 --- H2-Pst ?=-9.9 H2 (Car YSO) posterior probability
52- 56 F5.2 --- H3-Pst ?=-9.9 H3 (background*) posterior probability
58- 62 F5.2 --- H4-Pst ?=-9.9 H4 (extragalactic) posterior probability
64 I1 --- Class [0,4] Assigned classification (2)
66- 69 F4.1 keV Emed ?=-9.9 Median energy
71- 74 F4.1 [cm-2/s] logF Log of total X-ray photon flux
76- 79 F4.1 [cm-2] logNH ?=-9.9 log(H column density) for YSOs (H2 class)
81- 84 F4.1 [10-7W] logL ?=-9.9 log(total X-ray luminosity) for YSOs (H2)
86- 89 F4.1 [cm-2] logNHo ?=-9.9 log(H column density) for non-YSO sources
91- 94 F4.1 [10-7W] logLo ?=-9.9 log(total X-ray luminosity) for non-YSOs.
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Note (1): The first 14368 sources of the CCCP catalog (Broos et al., 2011,
Cat. J/ApJS/194/2), sorted by RA; the 14369th source in the CCCP
catalog was identified too late in the data analysis process to be
included. Names are in Simbad.
Note (2): Classification as follows:
1 = class H1 (foreground Galactic field star):
Prob(H1|F)>2*max{Prob(H2|F),Prob(H3|F),Prob(H4|F)}; 716 sources
2 = class H2 (Carina young star):
Prob(H2|F)>2*max{Prob(H1|F),Prob(H3|F),Prob(H4|F)}; 10714 sources
3 = class H3 (background Galactic field star):
Prob(H3|F)>2*max{Prob(H1|F),Prob(H2|F),Prob(H4|F)}; 16 sources
4 = Class H4 (extragalactic):
Prob(H4|F)>2*max{Prob(H1|F),Prob(H2|F),Prob(H3|F)}; 877 sources
0 = Unclassified; 2045 sources
See section 4.4 for further details.
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History:
* 24-May-2011: From electronic version of the journal
* 17-Jun-2011: corrected CXOGNC names supplied by the author on request
(original CXOGNC names missed their 3 last characters corresponding
to seconds and tenths of seconds)
References:
Townsley et al. CCCP introduction 2011ApJS..194....1T 2011ApJS..194....1T
Broos et al. CCCP catalog Cat. J/ApJS/194/2
Getman et al. Contamination in X-ray studies 2011ApJS..194....3G 2011ApJS..194....3G
Broos et al. Source classifier Cat. J/ApJS/194/4
Gagne et al. O and B stars Cat. J/ApJS/194/5
Povich et al. Cand. X-ray emitting OB stars Cat. J/ApJS/194/6
Naze et al. O and B stars X-ray properties Cat. J/ApJS/194/7
Parkin et al. QZ Car (HD 93206) 2011ApJS..194....8P 2011ApJS..194....8P
Feigelson et al. X-ray star clusters Cat. J/ApJS/194/9
Preibisch et al. NIR properties of YSO Cat. J/ApJS/194/10
Wang et al. Trumpler 15 Cat. J/ApJS/194/11
Wolk et al. Trumpler 16 Cat. J/ApJS/194/12
Povich et al. Pan-Carina YSO catalog Cat. J/ApJS/194/14
Evans et al. Companions of B stars in Tr 16 2011ApJS..194...13E 2011ApJS..194...13E
Townsley et al. Diffuse X-ray emission Cat. J/ApJS/194/15
Townsley et al. Comparison of diffuse emission 2011ApJS..194...16T 2011ApJS..194...16T
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 24-May-2011