J/ApJ/566/974 CHANDRA obs. of YSOs in OMC-2 and OMC-3 (Tsujimoto+, 2002)
X-ray properties of young stellar objects in OMC-2 and OMC-3 from the
Chandra X-ray observatory.
Tsujimoto M., Koyama K., Tsuboi Y., Goto M., Kobayashi N.
<Astrophys. J. 566, 974 (2002)>
=2002ApJ...566..974T 2002ApJ...566..974T
ADC_Keywords: X-ray sources ; Stars, pre-main sequence ; Photometry, infrared
Mission_Name: Chandra
Keywords: infrared: stars - SM: individual (OMC-2, OMC-3) -
stars: pre-main-sequence - X-rays: stars
Abstract:
We report X-ray results of the Chandra observation of OMC-2 and OMC-3.
A deep exposure of ∼100ks detects ∼400 X-ray sources in the field of
view of the ACIS array, providing one of the largest X-ray catalogs in
a star-forming region. Coherent studies of the source detection, time
variability, and energy spectra are performed. We classify the X-ray
sources into Class I, Class II, and Class III+MS based on the J-, H-,
and K-band colors of their near-infrared counterparts and discuss the
X-ray properties (temperature, absorption, and time variability) along
these evolutionary phases.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 49 398 Results of Imaging Analysis and NIR Identification
table2.dat 88 123 Results of Timing and Spectroscopic Analysis
table3.dat 109 23 Best-fit Values of Two-Temperature Thin-Thermal
Plasma Model
--------------------------------------------------------------------------------
See also:
J/ApJ/567/423 : CHANDRA obs. of YSOs in Monoceros R2 (Kohno+, 2002)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- [TKT2002] Object source identification (1)
6- 23 A18 --- Name Object name (hhmmss.ss-ddmmss.s) (2)
25- 29 I5 ct XCts X-ray photon counts in 0.5-8.0keV band
31- 35 F5.2 --- HR Hardness ratio (3)
37- 42 F6.3 mag J-H ? The (J-H) color (4)
44- 49 F6.3 mag H-K ? The (H-K) color (4)
--------------------------------------------------------------------------------
Note (1): Results of X-ray imaging analysis and 2MASS correlation
are listed for all the detected X-ray sources.
I1-I354 and S1-S11 are detected in the total band image (0.5-8.0keV)
image of the ACIS-I and the ACIS-S2.
I355-I369 and S12-S13 are detected only in the hard band (2.0-8.0keV)
image of the ACIS-I and the ACIS-S2.
I370-I385 are detected only in the soft band (0.5-2.0keV) image of the
ACIS-I.
No new source was detected in the soft band image of the ACIS-S2.
Note (2): Sources are named after their position in the equinox J2000.
Note (3): Defined as (H-S)/(H+S) where H and S are photon counts in the hard
band (2.0-8.0keV) and in the soft band (0.5-2.0keV) respectively.
Note (4): In CIT color system derived from 2MASS J, H, and Ks band
photometry (see Carpenter, 2001AJ....121.2851C 2001AJ....121.2851C).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- [TKT2002] Object source identification (1)
6 A1 --- f_[TKT2002] [d] Indicates source with time-variability
8- 12 F5.3 --- UProb Upper probability (2)
14- 17 F4.2 10+22/cm2 NH Column density
19- 22 F4.2 10+22/cm2 e_NH Lower 1σ confidence level to NH
24- 27 F4.2 10+22/cm2 E_NH Upper 1σ confidence level to NH
29- 33 F5.2 keV Temp Temperature (3)
35- 38 F4.2 keV e_Temp Lower 1σ confidence level to Temp
40- 44 F5.2 keV E_Temp Upper 1σ confidence level to Temp
46- 49 F4.2 [Sun] Z Metallicity relative to solar photospheric
from Morrison & McCammon,
1983ApJ...270..119M 1983ApJ...270..119M (3)
52- 55 F4.2 [Sun] e_Z Lower 1σ confidence level to Z
57- 60 F4.2 [Sun] E_Z Upper 1σ confidence level to Z
62- 67 F6.2 10+22W XLum X-ray luminosity in units of 10+29erg/s (4)
69- 74 F6.2 10+22W e_XLum Lower 1σ confidence level to XLum
76- 81 F6.2 10+22W E_XLum Upper 1σ confidence level to XLum
83- 88 A6 --- Class Classification based on J, H, Ks
magnitude of 2MASS counterpart (G1)
--------------------------------------------------------------------------------
Note (1): Results of timing and spectroscopic analysis are listed for
all the "bright2" sources. Best-fit parameters of thin-thermal
plasma model fitting are tabulated regardless whether the fit is
accepted or rejected.
Note (2): Defined as the integral from α to infinity of
Χν2(x) dx
where the Χν2(x) value and the degree of freedom of the fit
is α and ν. Fits with the upper probability larger than 0.01
are "accepted" while those less than or equal to 0.01 are "rejected".
Even the "best-fit" parameters of rejected fittings represent values
of some physical meaning or approximated values. We thus use these
values in the same way with the accepted ones.
Note (3): The best fit value of temperature and metallicity are searched
for in the range of less than 20keV and 5 solar respectively.
Note (4): In the 0.5-8.0keV band and corrected for absorption.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- [TKT2002] Object source identification (1)
6- 9 F4.2 10+22/cm2 NH Column density
11- 14 F4.2 10+22/cm2 e_NH Lower 1σ confidence level to NH
16- 19 F4.2 10+22/cm2 E_NH Upper 1σ confidence level to NH
21- 24 F4.2 keV TempL Lower temperature component value (2)
26- 29 F4.2 keV e_TempL Lower 1σ confidence level to TempL
31- 34 F4.2 keV E_TempL Upper 1σ confidence level to TempL
36- 40 F5.2 keV TempH Higher temperature component value (2)
42- 45 F4.2 keV e_TempH Lower 1σ confidence level to TempH
47- 51 F5.2 keV E_TempH Upper 1σ confidence level to TempH
53- 56 F4.2 [Sun] Z Metallicity relative to solar photospheric
of Morrison & McCammon,
1983ApJ...270..119M 1983ApJ...270..119M (2)
58- 61 F4.2 [Sun] e_Z Lower 1σ confidence level to Z
63- 66 F4.2 [Sun] E_Z Upper 1σ confidence level to Z
68- 72 F5.2 10+22W XLumL Lower component X-ray luminosity
in units of 10+29erg/s (3)
74- 78 F5.2 10+22W e_XLumL Lower 1σ confidence level to XLumL
80- 84 F5.2 10+22W E_XLumL Upper 1σ confidence level to XLumL
86- 90 F5.2 10+22W XLumH Higher component X-ray luminosity
in units of 10+29erg/s (3)
92- 96 F5.2 10+22W e_XLumH Lower 1σ confidence level to XLumH
98-102 F5.2 10+22W E_XLumH Upper 1σ confidence level to XLumH
104-109 A6 --- Class Classification based on J, H, Ks
magnitude of 2MASS counterpart (G1)
--------------------------------------------------------------------------------
Note (1): Accepted fits are listed.
Note (2): The absorption and the metallicity of the higher temperature
component is fixed to be the same with those of the lower temperature
component. The best fit value of temperature and metallicity are
searched for in the range of less than 20keV and 5 solar respectively.
Note (3): In the 0.5-8.0keV band and corrected for absorption.
--------------------------------------------------------------------------------
Global notes:
Note (G1): Classification:
I = class I;
II = class II;
III+MS = class III+MS;
others = source which are out of these groups.
no data = source can not be classified due to their lack of a
NIR counterpart.
--------------------------------------------------------------------------------
History:
* 25-Apr-2002: From electronic version of the journal
* 28-Dec-2006: Table1 corrected, from erratum published in 2003 ApJ, 585, 602
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 25-Apr-2002