J/A+A/682/A49 EWOCS-I. X-ray sources in Westerlund 1 (Guarcello+, 2024)
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the
Extended Westerlund 1 and 2 Open Clusters Survey.
Guarcello M.G., Flaccomio E., Albacete-Colombo J.F., Almendros-Abad V.,
Anastasopoulou K., Andersen M., Argiroffi C., Bayo A., Bartlett E.S.,
Bastian N., De Becker M., Best W., Bonito R., Borghese A., Calzetti D.,
Castellanos R., Cecchi-Pestellini C., Clark S., Clarke C.J., Coti Zelati F.,
Damiani F., Drake J.J., Gennaro M., Ginsburg A., Grebel E.K., Hora J.L.,
Israel G.L., Lawrence G., Locci D., Mapelli M., Martinez-Galarza J.R.,
Micela G., Miceli M., Moraux E., Muzic K., Najarro F., Negueruela I.,
Nota A., Pallanca C., Prisinzano L., Ritchie B., Robberto M., Rom T.,
Sabbi E., Scholz A., Sciortino S., Trigilio C., Umana G., Winter A.,
Wright N.J., Zeidler P.
<Astron. Astrophys. 682, A49 (2024)>
=2024A&A...682A..49G 2024A&A...682A..49G (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Radio sources
Keywords: stars: formation - stars: low-mass - stars: massive -
stars: Wolf-Rayet - X-rays: stars -
galaxies: star clusters: individual: Westerlund 1
Abstract:
With a mass exceeding several 104M☉ and a rich and dense
population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated
by the feedback from massive stars and gravitational interactions
among stars.
In this paper we present the Extended Westerlund 1 and 2 Open Clusters
Survey (EWOCS) project, which aims to investigate the influence of the
starburst environment on the formation of stars and planets, and on
the evolution of both low and high mass stars. The primary targets of
this project are Westerlund 1 and 2, the closest supermassive star
clusters to the Sun.
The project is based primarily on recent observations conducted with
the Chandra and JWST observatories. Specifically, the Chandra survey
of Westerlund 1 consists of 36 new ACIS-I observations, nearly
co-pointed, for a total exposure time of 1Msec. Additionally, we
included 8 archival Chandra/ACIS-S observations. This paper presents
the resulting catalog of X-ray sources within and around Westerlund 1.
Sources were detected by combining various existing methods, and
photon extraction and source validation were carried out using the
ACIS-Extract software.
The EWOCS X-ray catalog comprises 5963 validated sources out of the
9420 initially provided to ACIS-Extract, reaching a photon flux
threshold of approximately 2x10-8 photons/cm2/s. The X-ray sources
exhibit a highly concentrated spatial distribution, with 1075 sources
located within the central 1-arcmin. We have successfully detected
X-ray emissions from 126 out of the 166 known massive stars of the
cluster, and we have collected over 71000 photons from the magnetar
CXO J164710.20-455217.
Description:
We present the list of the X-ray sources in and around the young
supermassive star cluster Westerlund 1, detected as part of the EWOCS
(Extendend Westerlund 1 and 2 Open Clusters Survey) from observations
performed with Chandra ACIS-I and ACIS-S.
The X-ray sources in Westerlund 1 are extracted and validated using
the ACIS Extract software. The catalog contains source positions and
X-ray photometry (counts, net-counts and photon flux) extracted in
four different energy bands, together with the photon median energy in
the 0.5-7.9keV band.
Objects:
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RA (2000) DE Designation(s)
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16 47 02.40 -45 51 07.2 Westerlund 1 = Cl Westerlund 1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 294 5963 Catalog of the X-ray sources in Westerlund 1
tableb1.dat 72 139 EWOCS X-ray counterparts of the massive stars
in Westerlund 1 listed in Clark et al.
(2020A&A...635A.187C 2020A&A...635A.187C, Cat. J/A+A/635/A187)
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See also:
J/A+A/477/147 : X-ray sources in Westerlund 1 (Clark+, 2008)
J/AJ/133/2696 : BVRI light curves of Westerlund 1 stars (Bonanos, 2007)
J/AJ/145/46 : UBVIc photometry in Westerlund 1 (Lim+, 2013)
J/MNRAS/472/1760 : Hierarchical formation of Westerlund 1 (Gennaro+, 2017)
J/A+A/632/A38 : Westerlund 1 reduced images of radio emission
(Andrews+, 2019)
J/A+A/635/A187 : Massive binaries in Westerlund 1. VII. (Clark+, 2020)
J/A+A/660/A89 : massive binaries in Westerlund 1. VIII. (Ritchie+, 2022)
J/A+A/664/A146 : Westerlund 1 under light of Gaia EDR3 (Negueruela+, 2022)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- EWOCS [1/5963] Source identifier (EWOCSXID)
6- 23 A18 --- Name Source IAU designation, HHMMSS.ss+DDMMSS.s
(CATALOG_NAME)
25- 34 F10.6 deg RAdeg Right Ascension (J2000) (RA)
36- 45 F10.6 deg DEdeg Declination (J2000) (DEC)
47- 51 F5.3 arcsec e_RAdeg Right declination error (ERR_RA)
53- 57 F5.3 arcsec e_DEdeg Declination error (ERR_DEC)
59- 67 F9.6 arcmin Theta Off-axis angle (THETA)
69- 73 I5 ct CtotT Total counts in 0.5-7.9keV band (C_T)
75- 77 I3 ct CtotS Total counts in 0.5-1.0keV band (C_S)
79- 83 I5 ct CtotM Total counts in 1.0-2.0keV band (C_M)
85- 89 I5 ct CtotH Total counts in 2.0-7.9keV band (C_H)
91-102 E12.6 ct CnetT Net counts in 0.5-7.9keV band (CNET_T)
104-115 E12.6 ct CnetS Net counts in 0.5-1.0keV band (CNET_S)
117-128 E12.6 ct CnetM Net counts in 1.0-2.0keV band (CNET_M)
130-141 E12.6 ct CnetH Net counts in 2.0-7.9keV band (CNET_H)
143-151 F9.5 ct E_CnetT Upper error of net counts in 0.5-7.9keV band
(CNETTHI)
153-160 F8.5 ct E_CnetS Upper error of net counts in 0.5-1.0keV band
(CNETSHI)
162-170 F9.5 ct E_CnetM Upper error of net counts in 1.0-2.0keV band
(CNETMHI)
172-180 F9.5 ct E_CnetH Upper error of net counts in 2.0-7.9keV band
(CNETHHI)
182-190 F9.5 ct e_CnetT Lower error of net counts in 0.5-7.9keV band
(CNETTLO)
192-200 F9.6 ct e_CnetS ?=- Lower error of net counts in 0.5-1.0keV
band (CNETSLO)
202-211 F10.6 ct e_CnetM ?=- Lower error of net counts in 1.0-2.0keV
band (CNETMLO)
213-222 F10.6 ct e_CnetH ?=- Lower error of net counts in 2.0-7.9keV
band (CNETHLO)
224-232 F9.6 keV Emedian Median photon energy in the 0.5-7.9keV band
(E_MEDIAN)
234-245 E12.6 ph/cm2/s FphT Photon flux in 0.5-7.9keV band (FPHOTONST)
247-258 E12.6 ph/cm2/s FphS Photon flux in 0.5-1.0keV band (FPHOTONSS)
260-271 E12.6 ph/cm2/s FphM Photon flux in 1.0-2.0keV band (FPHOTONSM)
273-284 E12.6 ph/cm2/s FphSH Photon flux in 2.0-7.9keV band (FPHOTONSH)
286-294 F9.5 [-] logPBest ?=- Best of ProbNoSource (LOGP_BEST)
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- ID Name in Clark et al. (2020A&A...635A.187C 2020A&A...635A.187C,
Cat. J/A+A/635/A187)
7- 21 A15 --- SpType Spectral type
23- 40 A18 --- Name Catalog name (HHMMSS.ss+DDMMSS.s)
42- 47 F6.1 ct CnetT Net counts in 0.5-7.9keV band
49- 54 F6.1 ct B_CnetT Upper value of net counts
in 0.5-7.9keV band interval
56- 61 F6.1 ct b_CnetT Lower value of net counts
in 0.5-7.9keV band interval
63- 68 E6.2 ph/cm2/s FphT Photon flux in 0.5-7.9keV band
70- 72 F3.1 arcsec Sep Separation between EWOCS and Clark et al.
(2020A&A...635A.187C 2020A&A...635A.187C) sources
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Acknowledgements:
Mario Guarcello, mario.guarcello(at)inaf.it
History:
02-Feb-2024: on-line version
28-Jun-2024: table b1 added (from elecronic version)
(End) Patricia Vannier [CDS] 27-Nov-2023