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CHANULXCAT - Chandra Archive Of Galaxies Ultraluminous X-Ray Source Catalog |
HEASARC Archive |
The ultraluminous X-ray source population from the Chandra archive of galaxies. Swartz D.A., Ghosh K.K., Tennant A.F., Wu K. <Astrophys. J. Suppl. Ser., 154, 519-539 (2004)> =2004ApJS..154..519S
Galaxy_Name
The name of the galaxy in which the ULX lies or is projected
against.
Name
The name for the X-ray source using the '[SGT2004]' prefix and the
truncated J2000.0 coordinates (JHHMMSS.ss+DDMMSS.s), as recommended by 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 0.01 seconds of time in the
original table.
Dec
The Declination of the X-ray source in the selected equinox. This was
given in J2000.0 coordinates to a precision of 0.1 arcseconds in the
original table.
LII
The Galactic Longitude of the X-ray source.
BII
The Galactic Latitude of the X-ray source.
Spect_Shape
A parameter describing the X-ray spectrum, generally the
power-law index, found from the best-fit absorbed (ACISABS and PHABS
components) XSPEC-specific power-law model called PEGPWRLW, unless the
parameter spect_shape_flag is non-blank, in which case it is the black body
or thermal emission-line temperature.
Spect_Shape_Pos_Err
The upper (positive) error in the value of the spectral
parameter.
Spect_Shape_Neg_Err
The lower (negative) error in the value of the spectral
parameter.
Spect_Shape_Flag
This parameter flags cases where the spectral parameter is
not the power-law index, as follows:
b: it is the disk-blackbody model inner disk temperature, kT_inner, in keV. c: it is the thermal emission-line model temperature, kT, in keV.
NH
The equivalent hydrogen absorption column density, in H-atoms/cm^2, from
the best-fit model.
NH_Pos_Err
The upper (positive) error in the value of the equivelent
hydrogen column Density, in H-atoms/cm^2.
NH_Neg_Err
The lower (negative) error in the value of the equivelant
hydrogen column density, in H-atoms/cm^2.
Chi_Squared
The chi-squared value of the best-fit model.
DoF
The number of degrees of freedom of the best-fit model.
Lx_Obs
The observed X-ray luminosity of the source in the 0.5 to 8.0 keV
energy band, in erg/s, derived from the observed best-fit model flux and
the adopted distance to the galaxy in whose direction it lies (given in
Table 1 of the reference paper), i.e., the implicit assumption has been made
that the source lies at the same distance as the galaxy.
Lx_Obs_Error
The uncertainty in the observed X-ray luminosity, in erg/s.
Lx
The intrinsic (absorption-corrected) X-ray luminosity of the source in
the 0.5 to 8.0 keV energy band, in erg/s, derived from the corresponding
best-fit model flux and the adopted distance to the galaxy in whose direction
it lies (given in Table 1 of the reference paper), i.e., the implicit
assumption has been made that the source lies at the same distance as
the galaxy.
Lx_Error
The uncertainty in the intrinsic X-ray luminosity, in erg/s.
Lx_Flag
This flag parameter is set to 'd' if the intrinsic luminosity is
less than 10^39 erg/s when the X-ray spectrum is fit using a thermal
emission-line model.
Hardness_Ratio_1
The hard to medium energy color (hardness ratio) C_HM of
the X-ray source. Colors are defined using the background-substracted X-ray
counts in the following energy bands: S = the counts in the (0.5 - 1.0 keV)
band, M in the (1.0 - 2.0 keV) band, and H in the (2.0 - 8.0 keV) band.
Thus, the total (0.5 - 8.0 keV) band counts T = S + M + H, and
C_HM = (H - M)/T.
Hardness_Ratio_2
Ths medium to soft energy color (hardness ratio) C_MS of
the X-ray source. Colors are defined using the background-substracted X-ray
counts in the following energy bands: S = the counts in the (0.5 - 1.0 keV)
band, M in the (1.0 - 2.0 keV) band, and H in the (2.0 - 8.0 keV) band.
Thus, the total (0.5 - 8.0 keV) band counts T = S + M + H, and
C_MS = (M - S)/T.
Prob_Constant
The Kolmogorov-Smirnov probability P_KS that the X-ray source
was constant. The authors consider that sources with P_KS <= 0.001 are
significantly variable, and that those with 0.001 <= P_KS <= 0.04 are likely
to be variable. For the ULX candidates, there are 7 (4.5%) and 22 (14.3%) of
the sources, respectively, below these two thresholds.