- HEASARC Director: Dr. Alan P. Smale
- HEASARC Associate Director: Dr. Roger Brissenden
- NASA Official: Phil Newman
- Web Curator: Meredith Gibb
- Last Modified: 19-Jun-2007
| Browse this table... |
GC47TUCCXO - 47 Tuc Globular Cluster Chandra X-Ray Point Source Catalog |
HEASARC Archive |
The authors combined the results from wavdetect source detection runs with a threshold probability of 1 x 10^-5, in two energy bands (0.5 - 2.0 keV and 0.5 - 6.0 keV for the 2000 observations, and (0.3 - 2.0 keV and 0.3 - 6.0 keV for the 2002 observations), to make independent source lists for the 2000 and 2002 observations, given in Tables 2 and 3 of the reference paper, which have been combined in the present HEASARC table. A total of 146 sources were detected in this way in the 2000 observations (entries with dataset_year = 2000), while 300 sources were detected in the 2002 observations (dataset_year = 2002). A total of 143 of the sources were clearly detected in both observations, while only three of the sources from the 2000 observations were not detected in the 2002 observations.
A deep Chandra survey of the globular cluster 47 Tucanae:
catalog of point sources.
Heinke C.O., Grindlay J.E., Edmonds P.D., Cohn H.N., Lugger P.M.,
Camilo F., Bogdanov S., Freire P.C.
<Astrophys. J., 625, 796-824 (2005)>
=2005ApJ...625..796H
Dataset_Year
The data in this table are derived from two separate Chandra sequences of
observations, one set in 2000 (the data for which are listed in Table 3 of
the reference paper), the second (longer) set in 2002 (listed in Table 2 of
the reference paper). This HEASARC table combines the entries from both
datasets into a single table, and, in order to distinguish entries, the
HEASARC has created this parameter which, for a given X-ray sources,
identifies the corresponding observation year.
Source_Number
The WAVDETECT (W) detection number of the X-ray source.
Because of the iterative nature of source list construction over several
papers (Grindlay et al. 2001, 2002; Edmonds et al. 2003a, 2003b), the W
numbering scheme does not follow clear patterns and has holes (numbers that
do not correspond to real sources within the chosen field).
Alt_Name_1
An alternative X-ray source designation as recommended by the CDS
Dictionary of Nomenclature of Celestial Objects using the '[GHE2001] W' prefix
as first used in Grindlay et al. (2001, Science, 292, 2290) and the X-ray
(W) source number.
Name
The name for the X-ray source using the 'CXOGlb' prefix (for Chandra
X-Ray Observatory, Globular Cluster) and the J2000.0 equatorial coordinates
(JHHHMMSSs-DDMMSS), as registered with the CDS Dictionary of Nomenclature
of Celestial Objects.
RA
The Right Ascension of the X-ray source in the selected equinox.
This was given in J2000.0 coordinates to a precision of 0.001 seconds of time
in the reference paper. The X-ray positions were aligned to the international
celestial reference frame using the radio and/or HST optical follow-up
positions of cleanly detected millisecond pulsars (MSPs) in the field of view.
RA_Error
The 1-sigma error (corresponding to the 68% confidence limits) in
the Right Ascension of the X-ray source, in seconds of time.
Dec
The Declination of the X-ray source in the selected equinox.
This was given in J2000.0 coordinates to a precision of 0.01 arcseconds
in the reference paper. The X-ray positions were aligned to the international
celestial reference frame using the radio and/or HST optical follow-up
positions of cleanly detected millisecond pulsars (MSPs) in the field of view.
Dec_Error
The 1-sigma error (corresponding to the 68% confidence limits) in
the Declination of the X-ray source, in arcseconds.
LII
The Galactic Longitude of the X-ray source.
BII
The Galactic Latitude of the X-ray source.
Radial_Distance
The radial distance of the X-ray source from the center of
the 47 Tuc cluster (taken to be J2000.0 RA = 00h 24m 05.29s,
Dec = -72d 04' 52.3" as in de Marchi et al. 1996, APJ, 468, L51), in
arcseconds. This field is populated only for the 2002 dataset.
PSF_Fraction
The fraction of the 1.5 keV point-spread function (PSF)
enclosed by the extraction region for the X-ray source.
Exposure
The exposure time for the X-ray source, in seconds (s).
The HEASARC calculated the value of this parameter using the fractional
exposure times given in Tables 3 and 5 of the reference paper (CDS tables
table3.dat and table5.dat) and the nominal on-axis exposure times of
72155 and 281074 seconds for the 2000 and 2002 datasets, respectively.
Counts
The background-subtracted counts in the X-ray source in the
0.5 - 4.5 keV energy band.
Counts_Pos_Err
The upper limit 1-sigma (68% confidence) error in the
background-subtracted 0.5 - 4.5 keV counts.
Counts_Neg_Err
The lower limit 1-sigma (68% confidence) error in the
background-subtracted 0.5 - 4.5 keV counts.
SB1_Counts
The background-subtracted counts in the X-ray source in the
0.5 - 1.5 keV energy band.
SB1_Counts_Pos_Err
The upper limit 1-sigma (68% confidence) error in the
background-subtracted 0.5 - 1.5 keV counts.
SB1_Counts_Neg_Err
The lower limit 1-sigma (68% confidence) error in the
background-subtracted 0.5 - 1.5 keV counts
HB_Counts
The background-subtracted counts in the X-ray source in the
1.5 - 6.0 keV energy band.
HB_Counts_Pos_Err
The upper limit 1-sigma (68% confidence) error in the
background-subtracted 1.5 - 6.0 keV counts.
HB_Counts_Neg_Err
The lower limit 1-sigma (68% confidence) error in the
background-subtracted 1.5 - 6.0 keV counts.
Lx
The 0.5 - 6.0 keV luminosity of the X-ray source, in erg/s. Photon fluxes
were computed from the recorded counts, effective apertures, exposure times,
and effective area functions for each source. Assuming a 2 keV VMEKAL spectrum
(a reasonable approximation for the average spectrum of the fainter X-ray
sources; see Sections 5 and 7 of the reference paper), an absorbing column of
1.3 x 10^20 cm^-2, and a distance of 4.85 kpc, the authors derived conversion
factors of 5.93 x 10^36 and 4.94 x 10^36 erg photon^-1 cm^2 to convert from
photon flux to unabsorbed X-ray luminosity in the 0.5 - 6.0 and 0.5 - 2.5 keV
energy bands, respectively. To recover the directly measured photon fluxes in
photons cm^-2 s^-1, divide the quoted X-ray luminosities by these factors.
Lx_Pos_Err
The upper limit 1-sigma (68% confidence) error in the
0.5 - 6.0 keV luminosity, in erg/s.
Lx_Neg_Err
The lower limit 1-sigma (68% confidence) error in the
0.5 - 6.0 keV luminosity, in erg/s.
SB2_Lx
The 0.5 - 2.5 keV luminosity of the X-ray source, in erg/s. Photon
fluxes were computed from the recorded counts, effective apertures, exposure
times, and effective area functions for each source. Assuming a 2 keV VMEKAL
spectrum (a reasonable approximation for the average spectrum of the fainter
X-ray sources; see Sections 5 and 7 of the reference paper),
an absorbing column of
1.3 x 10^20 cm^-2, and a distance of 4.85 kpc, the authors derived conversion
factors of 5.93 x 10^36 and 4.94 x 10^36 erg photon^-1 cm^2 to convert from
photon flux to unabsorbed X-ray luminosity in the 0.5 - 6.0 and 0.5 - 2.5 keV
energy bands, respectively. To recover the directly measured photon fluxes in
photons cm^-2 s^-1, divide the quoted X-ray luminosities by these factors.
SB2_Lx_Pos_Err
The upper limit 1-sigma (68% confidence) error in the
0.5 - 2.5 keV luminosity, in erg/s.
SB2_Lx_Neg_Err
The lower limit 1-sigma (68% confidence) error in the
0.5 - 2.5 keV luminosity, in erg/s.
Source_Type
The classification of the source, defined as follows:
AB = active binary
CV = cataclysmic variable
qLX = quiescent low-mass X-ray binary containing where accretion onto
a neutron star is stopped or greatly reduced
AB = an X-ray active binary consisting of normal stars in a tidally locked
short-period binary, where the fast rotation rate drives increased
coronal activity
AGB = an AB from Albrow et al. (2001, CDS Cat. <J/ApJ/559/1060>) identified
with an X-ray source in this work.
MSP = millisecond radio pulsar
Source_Type_Flag
A value of '?' for this flag parameter indicates that there
is some uncertainty in the source classification.
Alt_Name_2
A second alternative name for the source, defined as follows:
AKO 9 = Auriere et al. (1989A&A...214..113A);
ROSAT X # = Verbunt & Hasinger (1998A&A...336..895V);
MSP lettering = Camilo et al. (2000ApJ...535..975C),
Freire et al. (2001MNRAS.326..901F), and
Edmonds et al. (2002ApJ...564L..17E, 2002ApJ...579..741E)
Note_Flags
This flag parameter contains notes indicating variability or
confusion, as follows:
Y = 99.9% confidence variability on years timescale;
D = 99.9% confidence variability on days timescale;
H = 99.9% confidence variability on hours timescale;
D? = 99% confidence variability on days timescale;
H? = 99% confidence variability on hours timescale;
t = not detected in the 2002 data; 2 of these may be spurious detections;
c = source may suffer from confusion;
m = source identified manually, rather than by WAVDETECT.
Class
The HEASARC Browse object classification, based on the value of
the source_type parameter.