J/ApJ/865/33 HST and Chandra obs. of the GLIMPSE-C01 star cluster (Hare+, 2018)
Chandra X-ray observatory and Hubble Space Telescope observations of the
intermediate-age cluster GLIMPSE-C01.
Hare J., Kargaltsev O., Rangelov B.
<Astrophys. J., 865, 33-33 (2018)>
=2018ApJ...865...33H 2018ApJ...865...33H (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular; X-ray sources; Photometry, HST;
Photometry, infrared
Keywords: globular clusters: individual: Glimpse-C01;
open clusters and associations: individual: Glimpse-C01;
X-rays: binaries
Abstract:
We report the results of Hubble Space Telescope and Chandra X-Ray
Observatory observations of the GLIMPSE-C01 (hereafter GC01) star
cluster. Color-magnitude and color-color diagrams suggest a cluster
age of ≳2Gyr up to ∼10Gyr (dependent on GC01's metallicity), a
distance of 3.3-3.5kpc, and strong differential reddening with
AV=14-22. After performing astrometric corrections, we find that
nine of the 15 X-ray sources have at least one near-infrared (NIR)
counterpart within the 2σ Chandra positional error circles.
However, given the very high density of NIR sources in the cluster,
most of these counterparts are likely due to chance coincidence. We
jointly analyze the X-ray and NIR properties to assess the likelihood
of true associations. Based primarily on their X-ray properties, we
identify a low-mass X-ray binary candidate (source X2), a cataclysmic
variable (CV) candidate (source X1), and an active binary (AB)
candidate (source X9). Source X11 is detected during an X-ray flaring
episode with a flare luminosity (LX=2.1x1033erg/s) and has a
quiescent luminosity LX<8.0x1030erg/s, in 0.5-8keV at the distance
of GC01, suggesting that the source is either an AB or CV. We also
discuss the limits on an intermediate-mass black hole at the center of
GC01 and the challenges of X-ray source classification imposed by the
limitations of the existing data and instrumentation along with future
prospects in the James Webb Space Telescope era.
Description:
The GLIMPSE C01 star cluster was observed by the HST during a
single-orbit visit on 2015 October 5 (GO 14183). The program consisted
of imaging observations with the Wide Field Camera 3 (WFC3), using
both the Ultraviolet-Visible (UVIS) and the infrared (IR) channels.
The UVIS F814W (wide I) filter and a set of medium NIR filters (F127M,
F139M, and F153M) were used. The data were downloaded from the
Mikulski Archive for Space Telescopes (MAST).
We have downloaded and reanalyzed the archival Chandra observation of
GC01. The data were taken on 2006 August 15 (ObsID 6587) with the
Advanced CCD Imaging Spectrometer (ACIS).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 99 15 X-ray sources detected with six or more net
counts in the ACIS-S3 image within the 42"
region of interest
table3.dat 82 12 Potential NIR counterparts to X-ray sources and
their magnitudes in the WFC3 IR and UVIS filters
127box.dat 159 1354 WFC3/UVIS+IR catalog for the "alternative cluster"
(box region) shown in Figure 5, derived using the
drizzled F127M image for source extraction, and
plotted in the right panel of Figure 9
127roi.dat 159 1964 WFC3/UVIS+IR catalog for the circular ROI region
shown in Figure 8, derived using the drizzled
F127M image for source extraction, and plotted
in the left panel of Figure 9
814roi.dat 159 777 WFC3/UVIS+IR catalog for the circular ROI region
shown in Figure 8, derived using the drizzled
F814W image for source extraction, and plotted
in Figure 10
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
B/chandra : The Chandra Archive Log (CXC, 1999-2014)
V/123 : Catalog of Cataclysmic Variables (Downes+ 2001-2006)
J/AJ/118/2894 : UBVRI CCD photometry in NGC 188 (Sarajedini+, 1999)
J/A+A/386/187 : Radial velocities in IC 4651 (Meibom+, 2002)
J/A+A/418/509 : Chandra observation of M67 (Van Den Berg+, 2004)
J/ApJ/625/796 : X-ray sources in the globular cluster 47 Tuc (Heinke+, 2005)
J/A+A/438/1163 : Catalogue of Open Cluster Data (COCD) (Kharchenko+, 2005)
J/AJ/132/1221 : VJHK and SDSS photometry of DA white dwarfs (Holberg+, 2006)
J/ApJ/651/1098 : Faint X-ray sources in Terzan 5 (Heinke+, 2006)
J/A+A/469/807 : Catalogue of Galactic low-mass X-ray binaries (Liu+, 2007)
J/A+A/489/583 : JHKs photometry of GLIMPSE-C02 (Kurtev+, 2008)
J/A+A/490/113 : X-ray sources in NGC 752 (Giardino+, 2008)
J/ApJ/697/224 : Chandra X-ray sources in ω Cen (Haggard+, 2009)
J/ApJ/729/L10 : KIC stars properties in NGC 6791 and NGC 6819 (Basu+, 2011)
J/MNRAS/419/1637 : Nearby red clump stars JHK observations (Laney+, 2012)
J/ApJ/770/98 : Chandra study of NGC 6791 (van den Berg+, 2013)
J/A+A/581/A39 : MWSC IV. 63 new open clusters (Scholz+, 2015)
J/A+A/589/A116 : Multiwavelength study of Sgr A* (Mossoux+, 2016)
J/ApJ/837/130 : Collinder 261 Chandra sources+opt. counterparts (Vats+, 2017)
J/ApJ/853/150 : Spectral analysis of low-mass X-ray binaries (Sonbas+, 2018)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- ID X-ray source identifier
5- 14 F10.6 deg RAdeg Source RA, decimal degrees (J2000)
16- 24 F9.6 deg DEdeg Source DEC, decimal degrees (J2000)
26- 29 F4.2 arcsec ePos X-ray 2σ position error circle radius
31- 32 I2 ct Net Net counts
34- 34 I1 ct E_Net ? Upper uncertainty in Net
36- 36 I1 ct e_Net Lower (or symmetric) uncertainty in Net (1)
38- 40 F3.1 10-14mW/m2 Fx Observed 0.5-8keV flux, 10-14erg/cm2/s
42- 44 F3.1 10-14mW/m2 E_Fx ? Upper uncertainty in Fx
46- 48 F3.1 10-14mW/m2 e_Fx Lower (or symmetric) uncertainty in Fx (1)
50- 50 A1 --- f_Fx Flag on Fx (2)
52- 56 F5.1 10+24J Lx Unabsorbed 0.5-8keV luminosity,
10+31erg/s at d=3.3kpc
58- 58 A1 --- f_Lx Flag on Lx (2)
60- 63 F4.1 --- Xcol ? X-ray color (3)
65- 65 A1 --- f_Xcol Flag on Xcol (2)
67- 69 F3.1 --- Emed Median photon energy in the 0.5-8keV band
71- 74 F4.1 --- Gamma Best fit photon index for the absorbed
power-law model
76- 78 F3.1 --- e_Gamma ? Symmetric uncertainty on Gamma
80- 80 A1 --- f_Gamma Flag on Gamma (2)
82- 86 F5.2 --- C-stat ? C-stat
88- 89 I2 --- dof ? Degrees of Freedom in fit
91- 92 I2 % PNIR Probability X-ray/NIR counterparts (4)
94- 94 A1 --- f_PNIR Flag on PNIR (2)
96- 97 I2 % Popt Probability X-ray/optical+NIR
counterparts (5)
99 A1 --- f_Popt Flag on Popt (2)
--------------------------------------------------------------------------------
Note (1): When a lower error limit but no upper error limit is given the error
bar is symmetric, e.g., Net±e_Net.
Note (2): Flags as follows:
i = Average observed flux and unabsorbed luminosity. During the 200s
flare the source reached a peak flux F_X=10-12erg/cm2/s and
unabsorbed luminosity L_X=2.1*1033erg/s in the 0.5-8keV band,
assuming d=3.3kpc. See Section 4.5, Discussion of Distance and Age.
g = Sources have no counts detected in the soft (0.5-2.0keV) band.
h = Photon index set to Γ=1.0 for sources with < 30 counts.
l = The NIR sources is just outside of the 2σ positional error
circle of this source, so we adopt the distance to the NIR source
(delta_r=0.35 arcsec) when calculating the chance coincidence
probability.
Note (3): X-ray color defined as
Xcolor=log(Funabs0.5-2keV/Funabs2-6keV).
Note (4): Probability that the X-ray source has 1 or more NIR counterparts
within its 2σ positional error circle due to chance
(see Section 3.3, Optical and NIR Counterparts to X-ray Sources).
Note (5): Probability that the X-ray source has 1 or more optical+NIR
counterparts within its 2σ positional error circle due to chance
(see Section 3.3, Optical and NIR Counterparts to X-ray Sources).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- ID Counterpart name (X-ray source identifier)
4- 5 A2 --- m_ID Multiple counterpart component identifier
7- 9 A3 --- f_ID Counterpart flag(s) (1)
11- 20 F10.6 deg RAdeg Counterpart RA, decimal degrees (J2000)
22- 30 F9.6 deg DEdeg Counterpart DEC, decimal degrees (J2000)
32- 37 F6.3 mag F814Wmag ? WFC3/UVIS F814W VEGAMAG magnitude (2)
39- 43 F5.3 mag e_F814Wmag ? uncertainty of F814W magnitude (3)
45- 50 F6.3 mag F127Wmag WFC3/UVIS F127W VEGAMAG magnitude
52- 56 F5.3 mag e_F127Wmag uncertainty of F127W magnitude (3)
58- 63 F6.3 mag F139Wmag WFC3/UVIS F139W VEGAMAG magnitude
65- 69 F5.3 mag e_F139Wmag uncertainty of F139W magnitude (3)
71- 76 F6.3 mag F153Wmag WFC3/UVIS F153W VEGAMAG magnitude
78- 82 F5.3 mag e_F153Wmag uncertainty of F153W magnitude (3)
--------------------------------------------------------------------------------
Note (1): Counterpart flag(s) as follows:
c = The source is resolved into two individual sources in the higher
resolution UVIS image;
d = This NIR/optical source lies just outside of the X-ray positional
error circle. However, due to the highly variable nature of this
X-ray source, we consider it as a potential NIR/Optical counterpart;
e = Unlike other sources, this source meets the criteria to be included
in the photometric catalog (i.e., SNR > 4, crowd < 0.2, and
sharp < 0.03.
Note (2): UVIS magnitude for sources detected with SNR > 10.
Note (3): The magnitude uncertainties are statistical only and do not
include systematic errors due to crowding.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: 127*.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.9 deg RAdeg [282.19/282.23] Source Right Ascension
(J2000) (1)
15- 28 F14.11 deg DEdeg [-1.53/-1.48] Source Declination (J2000) (1)
30- 35 F6.3 mag F814Wmag [15.7/35.4]? WFC3/UVIS F814W magnitude (2)
37- 41 F5.3 mag e_F814Wmag [0.001/10]? Uncertainty of F814W magnitude (2)
43- 47 F5.1 --- SNRF814W [0/736]? Signal-to-noise ratio of the source
in the F814W image (2)
49- 54 F6.3 --- shpF814W [-3.4/5.8]? Sharpness value of the source
in the F814W image (2)
56- 60 F5.3 --- crdF814W [0/7.7]? Crowding value of the source
in the F814W image (2)
62- 67 F6.3 mag F127Mmag [12/23]? WFC3/IR F127M magnitude
69- 73 F5.3 mag e_F127Mmag [0/0.2]? Uncertainty of F127M magnitude
75- 80 F6.1 --- SNRF127M [9/4177]? Signal-to-noise ratio of the source
in the F127M image
82- 87 F6.3 --- shpF127M [-0.03/0.03] Sharpness value of the source
in the F127M image
89- 93 F5.3 --- crdF127M [0.003/0.2]? Crowding value of the source
in the F127M image
95-100 F6.3 mag F139Mmag [11.4/22]? WFC3/IR F139M magnitude
102-106 F5.3 mag e_F139Mmag [0/0.06]? Uncertainty of F139M magnitude
108-113 F6.1 --- SNRF139M [18/5226]? Signal-to-noise ratio of the source
in the F139M image
115-120 F6.3 --- shpF139M [-0.03/0.03]? Sharpness value of the source
in the F139M image
122-126 F5.3 --- crdF139M [0.005/0.2]? Crowding value of the source
in the F139M image
128-133 F6.3 mag F153Mmag [10.5/21.2]? WFC3/IR F153M magnitude
135-139 F5.3 mag e_F153Mmag [0/0.04]? Uncertainty of F153M magnitude
141-146 F6.1 --- SNRF153M [27/7033]? Signal-to-noise ratio of the source
in the F153M image
148-153 F6.3 --- shpF153M [-0.03/0.03]? Sharpness value of the source
in the F153M image
155-159 F5.3 --- crdF153M [0.006/0.2]? Crowding value of the source
in the F153M image
--------------------------------------------------------------------------------
Note (1): The drizzled F127M image was used for source detection and
source coordinates.
Note (2): If a column is blank it means that no F814W source was detected with
a SNR>4 at the position of the F127M source.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: 814roi.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.9 deg RAdeg [282.19/282.22] Source Right Ascension
(J2000) (1)
15- 28 F14.11 deg DEdeg [-1.51/-1.48] Source Declination (J2000) (1)
30- 35 F6.3 mag F814Wmag [17/26.1]? WFC3/UVIS F814W magnitude
37- 41 F5.3 mag e_F814Wmag [0.002/0.3]? Uncertainty of F814W magnitude
43- 47 F5.1 --- SNRF814W [4/661]? Signal-to-noise ratio of the source
in the F814W image
49- 54 F6.3 --- shpF814W [-0.1/0.1]? Sharpness value of the source
in the F814W image
56- 60 F5.3 --- crdF814W [0/0.2]? Crowding value of the source
in the F814W image
62- 67 F6.3 mag F127Mmag [12.4/21.1]? WFC3/IR F127M magnitude
69- 73 F5.3 mag e_F127Mmag [0/0.03]? Uncertainty of F127M magnitude
75- 80 F6.1 --- SNRF127M [41/3548]? Signal-to-noise ratio of the source
in the F127M image
82- 87 F6.3 --- shpF127M [-0.03/0.02]? Sharpness value of the source
in the F127M image
89- 93 F5.3 --- crdF127M [0.004/0.2]? Crowding value of the source
in the F127M image
95-100 F6.3 mag F139Mmag [11.5/20.6]? WFC3/IR F139M magnitude
102-106 F5.3 mag e_F139Mmag [0/0.03]? Uncertainty of F139M magnitude
108-113 F6.1 --- SNRF139M [48/5113]? Signal-to-noise ratio of the source
in the F139M image
115-120 F6.3 --- shpF139M [-0.04/0.03]? Sharpness value of the source
in the F139M image
122-126 F5.3 --- crdF139M [0.005/0.4]? Crowding value of the source
in the F139M image
128-133 F6.3 mag F153Mmag [10.6/20.2]? WFC3/IR F153M magnitude
135-139 F5.3 mag e_F153Mmag [0/0.02]? Uncertainty of F153M magnitude
141-146 F6.1 --- SNRF153M [54/6661]? Signal-to-noise ratio of the source
in the F153M image
148-153 F6.3 --- shpF153M [-0.05/0.03]? Sharpness value of the source
in the F153M image
155-159 F5.3 --- crdF153M [0.007/0.5]? Crowding value of the source
in the F153M image
--------------------------------------------------------------------------------
Note (1): The drizzled F814M image was used for source detection and
source coordinates.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 20-Aug-2019