J/ApJS/163/306 Chandra study of the Cep B star-forming region (Getman+, 2006)
Chandra study of the Cepheus B star-forming region: stellar populations and the
initial mass function.
Getman K.V., Feigelson E.D., Townsley L., Broos P., Garmire G.,
Tsujimoto M.
<Astrophys. J. Suppl. Ser., 163, 306-334 (2006)>
=2006ApJS..163..306G 2006ApJS..163..306G
ADC_Keywords: X-ray sources ; Interstellar medium ; Molecular clouds ;
Stars, pre-main sequence
Keywords: ISM: individual (Cepheus molecular cloud) -
open clusters and associations: individual (Cepheus OB3) -
stars: formation - stars: luminosity function, mass function -
stars: pre-main-sequence - X-rays: stars
Abstract:
The Cepheus B (Cep B) molecular cloud and a portion of the nearby
Cep OB3b OB association, one of the most active regions of star
formation within 1kpc, have been observed with the ACIS detector on
board the Chandra X-Ray Observatory. We detect 431 X-ray sources,
of which 89% are confidently identified as clustered premain-sequence
(PMS) stars.
Description:
The observation of Cep B and Cep OB3b was obtained on 2003 March
11.51-11.88 with the ACIS camera on board Chandra.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 101 431 Basic source properties
table2.dat 88 431 2MASS counterparts
table3.dat 82 431 X-ray spectroscopy and luminosities
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/MNRAS/341/805 : UBVI CCD photometry of Cep OB3b (Pozzo+, 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [GFT2006] CepB source number
5- 22 A18 --- CXOCepB The IAU designation (HHMMSS.ss+DDMMSS.s)
24- 33 F10.6 deg RAdeg Right ascension in decimal degrees (J2000)
35- 43 F9.6 deg DEdeg Declination in decimal degrees (J2000)
45- 50 F6.2 arcmin OAxis The off-axis angle
52- 57 F6.1 ct NetF Net total band (0.5-8.0keV) counts (1)
59- 62 F4.1 ct e_NetF Error in NetF
64- 67 F4.1 ct BkgF Background total band (0.5-8.0keV)
counts extracted
69- 74 F6.1 ct NetH Net hard band (2.0-8.0keV) counts (1)
76- 79 F4.2 --- PSF Point spread fraction in extracted area at
fiducial energy 1.5keV
81- 84 F4.1 --- Sig Source significance (in sigma)
86- 89 A4 --- Anom Source anomalies (2)
91 A1 --- Var Source variability from K-S test (3)
93- 96 F4.1 ks Exp Effective exposure time
98-101 F4.2 keV MedE Median energy in total band corrected
for background
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Note (1): In extracted area.
Note (2): Source anomalies, defined as follows:
g... = fractional time when source is on a detector (FRACEXPO) is <0.9
.e.. = source on field edge
..p. = source piled up
...s = source on readout streak
Note (3): Source variability, defined as follows:
a = no evidence for variability
b = possibly variable
c = definitely variable
. = no test is performed for sources with <4 counts, or sources in
chip gaps or on field edges
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [GFT2006] CepB source number
5- 22 A18 --- CXOCepB The IAU designation (HHMMSS.ss+DDMMSS.s)
24- 39 A16 --- 2MASS The 2MASS source identification
41- 44 F4.2 arcsec Offset ? Chandra-2MASS source positional offset
46- 50 F5.2 mag Jmag ? 2MASS J band brightness
52- 56 F5.2 mag Hmag ? 2MASS H band brightness
58- 62 F5.2 mag Ksmag ? 2MASS Ks band brightness
64- 66 A3 --- q_2MASS 2MASS photometric quality flag (1)
68- 70 A3 --- f_2MASS 2MASS contamination and confusion flag (2)
72- 76 F5.2 mag Av ? Visual absorption (3)
78- 82 F5.2 solMass Mass ? Stellar mass (3)
84- 88 F5.2 [solLum] Lbol ? Stellar bolometric luminosity (3)
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Note (1): This is the phqual flag provided in the 2MASS All-Sky Data Release
where the three characters refer to the JHK bands, defined as follows:
A = very high significance detection (>10 SNR);
B = high significance detection (>7 SNR);
C = moderate significance detection (>5 SNR);
D = low significance detection;
E = point spread fitting poor;
F = reliable photometric errors not available;
U = upper limit on magnitude (source not detected);
X = source is detected but no valid brightness estimate is available.
Note (2): This is the ccflg provided in the 2MASS All-Sky Data Release where
the three characters refer to the JHK bands, defined as:
0 = source unaffected by artifacts;
b = bandmerge confusion (possible multiple source);
c = photometric confusion from nearby star;
d = diffraction spike confusion from nearby star;
p = persistence contamination from nearby star;
s = electronic stripe from nearby star.
Note (3): From the 2MASS color-magnitude diagram.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [GFT2006] CepB source number
5- 22 A18 --- CXOCepB The IAU designation (HHMMSS.ss+DDMMSS.s)
24- 28 F5.2 [cm-2] log(NH) Log of the Hydrogen column density
30- 34 F5.2 keV kT Plasma energy
36- 40 F5.2 [10-7W] Lh Log of observed hard band (2.0-8.0keV)
luminosity (1)
42- 45 F4.2 [10-7W] e_Lh Error in Lh from simulations (1)
47- 51 F5.2 [10-7W] Lhc Log of estimated hard band luminosity
corrected for absorption (1)
53- 56 F4.2 [10-7W] e_Lhc Error in Lhc from simulations (1)
58- 62 F5.2 [10-7W] Lt Log of observed total band (0.5-8.0keV)
luminosity (1)
64- 67 F4.2 [10-7W] e_Lt Error in Lt from simulations (1)
69- 73 F5.2 [10-7W] Ltc Log of estimated total band luminosity
corrected for absorption (1)
75- 78 F4.2 [10-7W] e_Ltc Error in Ltc from simulations (1)
80- 82 A3 --- MMDFl Source flag (2)
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Note (1): In units of erg/s.
Note (2): Three-part flag giving details on spectroscopy method, source
membership, and stars with K-disks, defined as follows:
b-- = spectral results from spectral fits of 174 relatively "bright"
sources with >20 net counts.
w-- = spectral results from NH_IR-MedE interpolation for 212 "weak"
sources with known NH_IR.
v-- = spectral results from fits of ungrouped spectra for 45 "weak"
sources with unknown NH_IR.
-e- = possible members of the embedded cluster.
-l- = possible members of the lightly absorbed cluster.
-o- = other possible members, found in the molecular cloud,
not related to the embedded cluster.
-a- = AGN candidates.
-f- = field star candidates.
--d = possible K-disk stars.
--0 = stars with no K-disk.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 31-Jul-2007