J/A+A/507/227 NGC 7129 pre-main sequence stars (Stelzer+, 2009)
A Chandra and Spitzer census of the young star cluster in the reflection
nebula NGC 7129.
Stelzer B., Scholz A.
<Astron. Astrophys., 507, 227-240 (2009)>
=2009A&A...507..227S 2009A&A...507..227S
ADC_Keywords: X-ray sources ; Infrared sources ; YSOs ;
Stars, pre-main sequence ; Photometry, infrared
Keywords: X-rays: stars - infrared: stars - stars: pre-main sequence -
stars: formation
Abstract:
The reflection nebula NGC 7129 has long been known to be a site of
recent star formation as shown, e.g., by the presence of deeply
embedded protostars and HH objects. However, studies of the stellar
population produced in the star formation process have remained
rudimentary. A major step forward has been made with recent Spitzer
imaging of the region.
This study represents the next step towards a systematic assessment of
the pre-main sequence population in NGC 7129. Completeness of the
pre-main sequence sample is necessary for studying key features that
allow the star-forming process to be understood, such as disk
evolution, dynamical evolution, and mass function. At a presumed age
of ∼3Myr, NGC 7129 is in the critical range where disks around
young stars disappear.
Description:
We make use of X-ray and IR imaging observations to identify the
pre-main sequence stars in NGC 7129. We define a sample of young
stellar objects based on color-color diagrams composed from IR
photometry between 1.6 and 8um, from 2MASS and Spitzer, and
based on X-ray detected sources from a Chandra observation.
A 22ks long Chandra observation targeting the Herbig star SVS 12 was
carried out on Mar 11, 2006 (start of observation UT 14h29m18s).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 75 59 X-ray parameters for all detected sources
table3.dat 38 59 Identification and offset between X-ray and
optical/IR position for counterparts of X-ray sources
table4.dat 130 59 Photometry and YSO classification for optical
and IR counterparts of X-ray sources
table5.dat 63 46 X-ray upper limits and 2MASS counterparts for
Class I sources not detected in X-rays
table6.dat 142 46 Candidate YSOs without X-ray emission selected
on basis of their IR photometry
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- --- [NGC 7129-]
10- 15 A6 --- ID Source name (SN-XN) (G1)
17- 18 I2 h RAh Right ascension (J2000)
20- 21 I2 min RAm Right ascension (J2000)
23- 27 F5.2 s RAs Right ascension (J2000)
29 A1 --- DE- Declination sign (J2000)
30- 31 I2 deg DEd Declination (J2000)
33- 34 I2 arcmin DEm Declination (J2000)
36- 39 F4.1 arcsec DEs Declination (J2000)
41- 43 F3.1 arcmin Offax Off-axis angle
45- 49 I5 s Exp Exposition time
51- 54 F4.1 10-3ct/s CRate Count rate in X-ray band (0.3-10keV)
56- 58 F3.1 10-3ct/s e_CRate rms uncertainty on CRate
60- 64 F5.1 --- Signi Significance
66- 70 F5.1 --- S/N Signal-to-noise ratio
72- 75 F4.1 [10-7W] logLX ?=- X-ray luminosity (1)
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Note (1): The X-ray luminosities were computed using the kT and NH
obtained from the hardness ratios as described in Sect. 2. LX is
given only for objects selected as pre-MS candidates with the
criteria described in Sect. 5.
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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- 9 A9 --- --- [NGC 7129-]
10- 15 A6 --- ID Source name (SN-XN) (G1)
17- 26 A10 --- OName Other name
29- 32 F4.2 arcsec X-opt ?=- Offset between X-ray and optical position
35- 38 F4.2 arcsec X-2M ?=- Offset between X-ray and infrared position
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- --- [NGC 7129-]
10- 15 A6 --- ID Source name (SN-XNN) (G1)
17- 21 F5.2 mag Vmag ?=- V magnitude
23- 27 F5.2 mag Rmag ?=- R magnitude
29- 33 F5.2 mag Imag ?=- I magnitude
36 A1 --- l_Jmag Limit flag on Jmag
37- 41 F5.2 mag Jmag ?=- 2MASS J magnitude
43- 46 F4.2 mag e_Jmag ? rms uncertainty on Jmag
48 A1 --- l_Hmag Limit flag on Hmag
49- 53 F5.2 mag Hmag ?=- 2MASS H magnitude
55- 58 F4.2 mag e_Hmag ? rms uncertainty on Hmag
60 A1 --- l_Kmag Limit flag on Kmag
61- 65 F5.2 mag Kmag ?=- 2MASS Ks magnitude
67- 70 F4.2 mag e_Kmag ? rms uncertainty on Kmag
72- 76 F5.2 mag [3.6] ?=- Spitzer/IRAC 3.6um magnitude
78- 81 F4.2 mag e_[3.6] ? rms uncertainty on [3.6]
83- 87 F5.2 mag [4.5] ?=- Spitzer/IRAC 4.5um magnitude
89- 92 F4.2 mag e_[4.5] ? rms uncertainty on [4.5]
94- 98 F5.2 mag [5.8] ?=- Spitzer/IRAC 5.8um magnitude
100-103 F4.2 mag e_[5.8] ? rms uncertainty on [5.8]
105-109 F5.2 mag [8.0] ?=- Spitzer/IRAC 8.0um magnitude
111-114 F4.2 mag e_[8.0] ? rms uncertainty on [8.0]
116-120 F5.2 mag [24] ?=- Spitzer/MIPS 24um magnitude
122-125 F4.2 mag e_[24] ? rms uncertainty on [24]
127-129 A3 --- YSO ?=- YSO class
130 A1 --- n_YSO [*] * identify objects selected on basis
of near-IR data
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- --- [NGC 7129-]
10- 17 A8 --- ID Source name (SN-UNNNN) (G1)
20- 21 I2 h RAh 2MASS right ascension (J2000)
23- 24 I2 min RAm 2MASS right ascension (J2000)
26- 30 F5.2 s RAs 2MASS right ascension (J2000)
32 A1 --- DE- 2MASS declination sign (J2000)
33- 34 I2 deg DEd 2MASS declination (J2000)
36- 37 I2 arcmin DEm 2MASS declination (J2000)
39- 42 F4.1 arcsec DEs Declination (J2000)
44- 46 F3.1 arcmin Offax Off-axis angle
48- 52 I5 s Exp Exposition time
54 A1 --- l_CRate Limit flag on CRate
55- 57 F3.1 10-3ct/s CRate Count rate in X-ray band (0.3-10keV)
59 A1 --- l_logLX Limit flag on logLX
60- 63 F4.1 [10-7W] logLX X-ray luminosity (1)
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Note (1): The upper limits to the X-ray luminosity were computed using
the median of kT and NH from the sample of X-ray detected ClassII
sources. These numbers may be underestimated if the extinction is much
higher, as is expected for the ClassI sources (see Sect. 6.4).
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- --- [NGC 7129-]
10- 17 A8 --- ID Source name (SN-UNNNN) (G1)
19- 26 A8 --- OName Other Name
29- 32 F4.2 arcsec O-S ?=- Difference in position between
ID and OName sources
34- 38 F5.2 mag Vmag ?=- V magnitude
40- 44 F5.2 mag Rmag ?=- R magnitude
46- 50 F5.2 mag Imag ?=- I magnitude
52- 56 F5.2 mag Jmag ?=- 2MASS J magnitude
58- 61 F4.2 mag e_Jmag ? rms uncertainty on Jmag
63- 67 F5.2 mag Hmag ?=- 2MASS H magnitude
69- 72 F4.2 mag e_Hmag ? rms uncertainty on Hmag
74- 78 F5.2 mag Kmag ?=- 2MASS Ks magnitude
80- 83 F4.2 mag e_Kmag ? rms uncertainty on Kmag
85- 89 F5.2 mag [3.6] ?=- Spitzer/IRAC 3.6um magnitude
91- 94 F4.2 mag e_[3.6] ? rms uncertainty on [3.6]
96-100 F5.2 mag [4.5] ?=- Spitzer/IRAC 4.5um magnitude
102-105 F4.2 mag e_[4.5] ? rms uncertainty on [4.5]
107-111 F5.2 mag [5.8] ?=- Spitzer/IRAC 5.8um magnitude
113-116 F4.2 mag e_[5.8] ? rms uncertainty on [5.8]
118-122 F5.2 mag [8.0] ?=- Spitzer/IRAC 8.0um magnitude
124-127 F4.2 mag e_[8.0] ? rms uncertainty on [8.0]
129-132 F4.2 mag [24] ?=- Spitzer/MIPS 24um magnitude
134-137 F4.2 mag e_[24] ? rms uncertainty on [24]
139-140 A2 --- YSO YSO class
141 A1 --- f_YSO [*] * identify objects selected on basis
of near-IR data
142 A1 --- AGN? [A] possible background AGN
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Global Notes:
Note (G1): Nomenclature used in Simbad:
<[SS2009] NGC 7129-SN-XNN> (tables 2, 3, 4)
<[SS2009] NGC 7129-SN-UNNN> (tables 5 and 6)
History:
From electronic version
(End) Patricia Vannier [CDS] 14-Sep-2010