J/ApJ/753/117 X-ray catalog of Eagle Nebula (Guarcello+, 2012)
Chandra/ACIS-I study of the X-ray properties of the NGC 6611 and M16 stellar
populations.
Guarcello M.G., Caramazza M., Micela G., Sciortino S., Drake J.J.,
Prisinzano L.
<Astrophys. J., 753, 117 (2012)>
=2012ApJ...753..117G 2012ApJ...753..117G
ADC_Keywords: Clusters, open ; X-ray sources
Keywords: open clusters and associations: individual (NGC 6611 and M16) -
stars: coronae - stars: massive - stars: pre-main sequence -
X-rays: stars
Abstract:
Mechanisms regulating the origin of X-rays in young stellar objects
and the correlation with their evolutionary stage are under debate.
Studies of the X-ray properties in young clusters allow us to
understand these mechanisms. One ideal target for this analysis is the
Eagle Nebula (M16), with its central cluster NGC 6611. At 1750pc from
the Sun, it harbors 93 OB stars, together with a population of
low-mass stars from embedded protostars to disk-less Class III
objects, with age ≤3Myr. We study an archival 78ks Chandra/ACIS-I
observation of NGC 6611 and two new 80ks observations of the outer
region of M16, one centered on the Column V and the other on a region
of the molecular cloud with ongoing star formation. We detect 1755
point sources with 1183 candidate cluster members (219 disk-bearing
and 964 disk-less). We study the global X-ray properties of M16 and
compare them with those of the Orion Nebula Cluster. We also compare
the level of X-ray emission of Class II and Class III stars and
analyze the X-ray spectral properties of OB stars. Our study supports
the lower level of X-ray activity for the disk-bearing stars with
respect to the disk-less members. The X-ray luminosity function (XLF)
of M16 is similar to that of Orion, supporting the universality of the
XLF in young clusters. Eighty-five percent of the O stars of NGC 6611
have been detected in X-rays. With only one possible exception, they
show soft spectra with no hard components, indicating that mechanisms
for the production of hard X-ray emission in O stars are not operating
in NGC 6611.
Description:
Description of the X-ray properties of 1753 sources derived from three
Chandra/ACIS-I observations, together with a source classification
based on the optical and infrared properties of each source. Data come
from three observations (central, east and north-east) and many values
are not averaged but presented for each observation (usually in the
order central, east, north-east)
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
xraycat.dat 650 1754 X-ray catalog of sources in the Eagle Nebula
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See also:
J/ApJ/654/347 : Chandra X-ray observations in Eagle Nebula. I. (Linsky+, 2007)
J/A+A/462/245 : BVI photometry in NGC 6611 (Guarcello+, 2007)
J/A+A/496/453 : Photometry of candidate members of NGC6611 (Guarcello+, 2009)
J/A+A/521/A18 : Blue stars with disk photometry in NGC6611 (Guarcello+, 2010)
J/A+A/521/A61 : Stars associated to Eagle Nebula (NGC6611) (Guarcello+ 2010)
Byte-by-byte Description of file: xraycat.dat
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Bytes Format Units Label Explanations
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4- 7 I4 --- ID [2/1924] Sequential source ID
11- 20 F10.6 deg RAdeg Right ascension (J2000.0)
24- 33 F10.6 deg DEdeg Declination (J2000.0)
35- 40 F6.3 arcmin thetaC ?=- Offset in the central observation
42- 47 F6.3 arcmin thetaE ?=- Offset in the east observation
49- 54 F6.3 arcmin thetaNE ?=- Offset in the north-east observation
61- 69 E9.4 --- PnsC ?=- Probabylity of no source associate with
this position in the central observation
76- 84 E9.4 --- PnsE ?=- Probabylity of no source associate with
this position in the east observation
91- 99 E9.4 --- PnsNE ?=- Probabylity of no source associate with
this position in the north-east observation
100-104 F5.2 --- SigniC ?=- Central observation source significance
105-109 F5.2 --- SigniE ?=- East observation source significance
110-114 F5.2 --- SigniNE ?=- North-east observation source
significance
120-131 A12 --- Class Source classification based on
optical-infrared colors (1)
132-138 F7.2 ct TctC Central observation total count in 0.5-8keV
140-145 F6.2 ct TctE East observation total count in 0.5-8keV
147-152 F6.2 ct TctNE North-east observation total count
in 0.5-8keV
153-159 F7.2 ct NctC ?=- Central observation net count
in 0.5-8keV
161-166 F6.2 ct NctE ?=- East observation net count in 0.5-8keV
168-173 F6.2 ct NctNE ?=- North-east observation net count
in 0.5-8keV
176-180 F5.3 --- psfC ?=- Fraction of the PSF at 1.497keV
corresponding to the extraction region in
the central observation
183-187 F5.3 --- psfE ?=- Fraction of the PSF at 1.497keV
corresponding to the extraction region in
the east observation
190-194 F5.3 --- psfNE ?=- Fraction of the PSF at 1.497keV
corresponding to the extraction region in
the north-east observation
196-205 E10.4 ct/s CRC ?=- Count-rate in 0.5-8keV band in the
central observation
208-216 E9.4 ct/s CRE ?=- Count-rate in 0.5-8keV band in the
east observation
218-227 E10.4 ct/s CRNE ?=- Count-rate in 0.5-8keV band in the
north-east observation
229-233 F5.3 keV EmedC ?=- Median photons energy in 0.5-8keV band
in the central observation
235-239 F5.3 keV EmedE ?=- Median photons energy in 0.5-8keV band
in the east observation
241-245 F5.3 keV EmedNE ?=- Median photons energy in 0.5-8keV band
in the north-east observation
247-252 F6.3 10+22cm-2 NHC ?=- Hydrogen column density in the
central observation
254-259 F6.3 10+22cm-2 E_NHC ?=- Upper value of NHC error
262-266 F5.3 10+22cm-2 e_NHC ?=- Lower value of NHC error
268-273 F6.3 10+22cm-2 NHE ?=- Hydrogen column density in the
east observation
275-280 F6.3 10+22cm-2 E_NHE ?=- Upper value of NHE error
282-287 F6.3 10+22cm-2 e_NHE ?=- lower value of NHE error
289-294 F6.3 10+22cm-2 NHNE ?=- Hydrogen column density in the
north-east observation
296-301 F6.3 10+22cm-2 E_NHNE ?=- Upper value of NHNE error
303-308 F6.3 10+22cm-2 e_NHNE ?=- Lower value of NHNE error
310-315 F6.3 keV kTC ?=- Plasma temperature in the
central observation
317-322 F6.3 keV E_kTC ?=- Upper value of kTC error
324-329 F6.3 keV e_kTC ?=- Lower value of kTC error
331-336 F6.3 keV kTE ?=- Plasma temperature in the
east observation
338-343 F6.3 keV E_kTE ?=- Upper value of kTE error
345-350 F6.3 keV e_kTE ?=- Lower value of kTE error
352-357 F6.3 keV kTNE ?=- Plasma temperature in the
north-east observation
359-364 F6.3 keV E_kTNE ?=- Upper value of kTNE error
366-371 F6.3 keV e_kTNE ?=- Lower value of kTNE error
376-380 F5.2 [mW/m2] logLXC ?=- Logarithm of the X-ray luminosity in
0.5-8keV in the central observation
386-389 F4.2 [mW/m2] E_logLXC ?=- Upper value of logLXC error
394-398 F5.2 [mW/m2] e_logLXC ?=- Lower value of logLXC error
399 A1 --- f_logLXC [i] i for infinity
403-407 F5.2 [mW/m2] logLXE ?=- Logarithm of the X-ray luminosity in
0.5-8keV in the east observation
413-416 F4.2 [mW/m2] E_logLXE ?=- Upper value of logLXE error
421-425 F5.2 [mW/m2] e_logLXE ?=- Lower value of logLXE error
426 A1 --- f_logLXE [i] i for infinity
430-434 F5.2 [mW/m2] logLXNE ?=- Logarithm of the X-ray luminosity in
0.5-8keV in the north-east observation
440-443 F4.2 [mW/m2] E_logLXNE ?=- Upper value of logLXNE error
449-452 F4.2 [mW/m2] e_logLXNE ?=- Lower value of logLXNE error
453 A1 --- f_logLXNE [i] i for infinity
456 I1 --- tagLXC Tag indicating whether the spectral
information in the central observation
have been obtained (2)
460 I1 --- tagLXE Tag indicating whether the spectral
information in the east observation
have been obtained (2)
464 I1 --- tagLXNE Tag indicating whether the spectral
information in the north-east observation
have been obtained (2)
468-477 A10 --- modelC Spectral model used to fit the source
spectrum in the central observation (3)
481-490 A10 --- modelE Spectral model used to fit the source
spectrum in the east observation (3)
494-503 A10 --- modelNE Spectral model used to fit the source
spectrum in the north-east observation (3)
506-510 F5.3 --- probKSC ?=- K-S statistic with the null hypothesis
that the source is not variable in the
0.5-8keV band in central observation
513-517 F5.3 --- probKSE ?=- K-S statistic with the null hypothesis
that the source is not variable in the
0.5-8keV band in east observation
520-524 F5.3 --- probKSNE ?=- K-S statistic with the null hypothesis
that the source is not variable in the
0.5-8keV band in north-east observation
526-531 F6.3 keV kT2C ?=- Second plasma temperature in the
central observation (4)
534-538 F5.3 keV E_kT2C ?=- Upper value of kT2C error
541-545 F5.3 keV e_kT2C ?=- Lower value of kT2C error
547-552 F6.3 keV kT2E ?=- Second plasma temperature in the
east observation(4)
555-559 F5.3 keV E_kT2E ?=- Upper value of kT2E error
562-566 F5.3 keV e_kT2E ?=- Lower value of kT2E error
568-573 F6.3 keV kT2NE ?=- Second plasma temperature in the
north-east observation (4)
576-580 F5.3 keV E_kT2NE ?=- Upper value of kT2NE error
583-587 F5.3 keV e_kT2NE ?=- Lower value of kT2NE error
589-594 F6.3 --- phC ?=- Photon index in the central
observation (5)
597-601 F5.3 --- E_phC ?=- Upper value of phC error
604-608 F5.3 --- e_phC ?=- Lower value of phC error
610-615 F6.3 --- phE ?=- Photon index in the
east observation (5)
618-622 F5.3 --- E_phE ?=- Upper value of phE error
625-629 F5.3 --- e_phE ?=- Lower value of phE error
631-636 F6.3 --- phNE ?=- Photon index in the
north-east observation (5)
639-643 F5.3 --- E_phNE ?=- Upper value of phNE error
646-650 F5.3 --- e_phNE ?=- Lower value of phNE error
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Note (1): see Guarcello et al., 2011, Cat. J/A+A/521/A61; the four
classes are Background, Foreground, Disk-less and Disk-bearing.
Note (2): Tag as follows:
1 = spectral fitting
2 = energy quantile analysis
3 = conversion from the count-rate
Note (3): values are: thermal_1T, thermal_2T, power_law
Note (4): for sources fitting a 2-temperature plasma model
Note (5): for sources fitting a power-low spectrum
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Acknowledgements:
Guarcello Mario Giuseppe, mguarcel(at)head.cfa.harvard.edu
(End) Guarcello Mario Giuseppe [CfA, USA], Patricia Vannier [CDS] 15-Nov-2012