Chandra X-Ray Observatory
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Last modified: 1 October 2018

Master Sources Table


Each distinct X-ray source identified on the sky is represented in the catalog by a single "master source" entry and one or more "per-observation detection" entries, one for each observation in which the source has been detected. The master source entry records the best estimates of the properties of a source, based on the data extracted from the set of observations in which the source has been detected.

Note: Source properties in the catalog which have a value for each science energy band (type "double[6]" and "integer[6]" in the table below) have the corresponding letters appended to their names. For example, "flux_aper_b" and "flux_aper_h" represent the background-subtracted, aperture-corrected broad-band and hard-band energy fluxes, respectively.

Go to: Catalog Columns Index | Context List
Column Name Type Units Description
acis_hetg_num integer total number of ACIS/HETG observations contributing to the Master Sources Table record of the source
acis_hetg_time double total exposure time (seconds of good time) for all ACIS/HETG observations contributing to the Master Sources Table record of the source
acis_letg_num integer total number of ACIS/LETG observations contributing to the Master Sources Table record of the source
acis_letg_time double total exposure time (seconds of good time) for all ACIS/LETG observations contributing to the Master Sources Table record of the source
acis_num integer total number of ACIS imaging observations contributing to the Master Sources Table record of the source
acis_time double total exposure time (seconds of good time) for all ACIS imaging observations contributing to the Master Sources Table record of the source
apec_abund double abundance of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum
apec_abund_hilim double abundance of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum (68% upper confidence limit)
apec_abund_lolim double abundance of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
apec_abund_rhat double abundance convergence criterion of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum
apec_kt double keV temperature (kT) of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum
apec_kt_hilim double keV temperature (kT) of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum (68% upper confidence limit)
apec_kt_lolim double keV temperature (kT) of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
apec_kt_rhat double temperature (kT) convergence criterion of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum
apec_nh double HI atoms 1020 cm-2 NH column density of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum
apec_nh_hilim double HI atoms 1020 cm-2 NH column density of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum (68% upper confidence limit)
apec_nh_lolim double HI atoms 1020 cm-2 NH column density of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
apec_nh_rhat double NH column density convergence criterion of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum
apec_norm double amplitude of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum
apec_norm_hilim double amplitude of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum (68% upperer confidence limit)
apec_norm_lolim double amplitude of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
apec_norm_rhat double amplitude convergence criterion of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum
apec_stat double χ2 statistic per degree of freedom of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum
apec_z double redshift of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum
apec_z_hilim double redshift of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum (68% upper confidence limit)
apec_z_lolim double redshift of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
apec_z_rhat double redshift convergence criterion Redshift of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum
bb_ampl double amplitude of the best fitting absorbed black body model spectrum to the source region aperture PI spectrum
bb_ampl_hilim double amplitude of the best fitting absorbed black body model spectrum to the source region aperture PI spectrum (68% upperer confidence limit)
bb_ampl_lolim double amplitude of the best fitting absorbed black body model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
bb_ampl_rhat double amplitude convergence criterion of the best fitting absorbed black body model spectrum to the source region aperture PI spectrum
bb_kt double keV temperature (kT) of the best fitting absorbed black body model spectrum to the source region aperture PI spectrum
bb_kt_hilim double keV temperature (kT) of the best fitting absorbed black body model spectrum to the source region aperture PI spectrum (68% upper confidence limit)
bb_kt_lolim double keV temperature (kT) of the best fitting absorbed black body model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
bb_kt_rhat double temperature (kT) convergence criterion of the best fitting absorbed black body model spectrum to the source region aperture PI spectrum
bb_nh double HI atoms 1020 cm-2 NH column density of the best fitting absorbed black body model spectrum to the source region aperture PI spectrum
bb_nh_hilim double HI atoms 1020 cm-2 NH column density of the best fitting absorbed black body model spectrum to the source region aperture PI spectrum (68% upper confidence limit)
bb_nh_lolim double HI atoms 1020 cm-2 NH column density of the best fitting absorbed black body model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
bb_nh_rhat double NH column density convergence criterion of the best fitting absorbed black body model spectrum to the source region aperture PI spectrum
bb_stat double χ2 statistic per degree of freedom of the best fitting absorbed black body model spectrum to the source region aperture PI spectrum
brems_kt double keV temperature (kT) of the best fitting absorbed bremsstrahlung model spectrum to the source region aperture PI spectrum
brems_kt_hilim double keV temperature (kT) of the best fitting absorbed bremsstrahlung model spectrum to the source region aperture PI spectrum (68% upper confidence limit)
brems_kt_lolim double keV temperature (kT) of the best fitting absorbed bremsstrahlung model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
brems_kt_rhat double temperature (kT) convergence criterion of the best fitting absorbed bremsstrahlung model spectrum to the source region aperture PI spectrum
brems_nh double HI atoms 1020 cm-2 NH column density of the best fitting absorbed bremsstrahlung model spectrum to the source region aperture PI spectrum
brems_nh_hilim double HI atoms 1020 cm-2 NH column density of the best fitting absorbed bremsstrahlung model spectrum to the source region aperture PI spectrum (68% upper confidence limit)
brems_nh_lolim double HI atoms 1020 cm-2 NH column density of the best fitting absorbed bremsstrahlung model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
brems_nh_rhat double NH column density convergence criterion of the best fitting absorbed bremsstrahlung model spectrum to the source region aperture PI spectrum
brems_norm double amplitude of the best fitting absorbed bremsstrahlung model spectrum to the source region aperture PI spectrum
brems_norm_hilim double amplitude of the best fitting absorbed bremsstrahlung model spectrum to the source region aperture PI spectrum (68% upperer confidence limit)
brems_norm_lolim double amplitude of the best fitting absorbed bremsstrahlung model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
brems_norm_rhat double amplitude convergence criterion of the best fitting absorbed bremsstrahlung model spectrum to the source region aperture PI spectrum
brems_stat double χ2 statistic per degree of freedom of the best fitting absorbed bremsstrahlung model spectrum to the source region aperture PI spectrum
conf_flag Boolean source may be confused (source and/or background regions overlap in one or more contributing stacked observations)
dec double deg source position, ICRS declination
dither_warning_flag boolean highest statistically significant peak in the power spectrum of the source region count rate occurs at the dither frequency or at a beat frequency of the dither frequency in one or more observations
err_ellipse_ang double deg position angle (referenced from local true north) of the major axis of the 95% confidence level error ellipse
err_ellipse_r0 double arcseconds major radius of the 95% confidence level position error ellipse
err_ellipse_r1 double arcseconds minor radius of the 95% confidence level position error ellipse
extent_flag Boolean source is extended, or deconvolved source extent is inconsistent with a point source at the 90% confidence level in one or more observations and science energy bands
flux_apec double ergs s-1 cm-2 net integrated 0.5-7.0 keV energy flux of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum
flux_apec_aper double[6] ergs s-1 cm-2 source region aperture model energy flux inferred from the canonical absorbed APEC model [NH = NH(Gal); kT = 6.5 keV] for each science energy band
flux_apec_aper90 double[6] ergs s-1 cm-2 PSF 90% ECF aperture model energy flux inferred from the canonical absorbed APEC model [NH = NH(Gal); kT = 6.5 keV] for each science energy band
flux_apec_aper90_hilim double[6] ergs s-1 cm-2 PSF 90% ECF aperture model energy flux inferred from the canonical absorbed APEC model [NH = NH(Gal); kT = 6.5 keV] (68% upper confidence limit)
flux_apec_aper90_lolim double[6] ergs s-1 cm-2 PSF 90% ECF aperture model energy flux inferred from the canonical absorbed APEC model [NH = NH(Gal); kT = 6.5 keV] (68% lower confidence limit)
flux_apec_aper_hilim double[6] ergs s-1 cm-2 source region aperture model energy flux inferred from the canonical absorbed APEC model [NH = NH(Gal); kT = 6.5 keV] (68% upper confidence limit) for each science energy band
flux_apec_aper_lolim double[6] ergs s-1 cm-2 source region aperture model energy flux inferred from the canonical absorbed APEC model [NH = NH(Gal); kT = 6.5 keV] (68% lower confidence limit) for each science energy band
flux_apec_hilim double ergs s-1 cm-2 net integrated 0.5-7.0 keV energy flux of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum (68% upper confidence limit)
flux_apec_lolim double ergs s-1 cm-2 net integrated 0.5-7.0 keV energy flux of the best fitting absorbed APEC model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
flux_aper double[6] ergs s-1 cm-2 aperture-corrected net energy flux inferred from the source region aperture, best estimate derived from the longest block of a multi-band, flux-ordered Bayesian Block analysis of the contributing observations, and calculated by counting X-ray events for each science energy band
flux_aper90 double[6] ergs s-1 cm-2 aperture-corrected net energy flux inferred from the PSF 90% ECF aperture, best estimate derived from the longest block of a multi-band, flux-ordered Bayesian Block analysis of the contributing observations, and calculated by counting X-ray events for each science energy band
flux_aper90_avg double[6] ergs s-1 cm-2 aperture-corrected net energy flux inferred from the PSF 90% ECF aperture, best estimate derived from the longest block of a multi-band, flux-ordered Bayesian Block analysis of the contributing observations, and calculated by counting X-ray events for each science energy band
flux_aper90_avg_hilim double[6] ergs s-1 cm-2 aperture-corrected net energy flux inferred from the PSF 90% ECF aperture, best estimate derived from the longest block of a multi-band, flux-ordered Bayesian Block analysis of the contributing observations, and calculated by counting X-ray events (68% upper confidence limit) for each science energy band
flux_aper90_avg_lolim double[6] ergs s-1 cm-2 aperture-corrected net energy flux inferred from the PSF 90% ECF aperture, best estimate derived from the longest block of a multi-band, flux-ordered Bayesian Block analysis of the contributing observations, and calculated by counting X-ray events (68% lower confidence limit) for each science energy band
flux_aper90_hilim double[6] ergs s-1 cm-2 aperture-corrected net energy flux inferred from the PSF 90% ECF aperture, best estimate derived from the longest block of a multi-band, flux-ordered Bayesian Block analysis of the contributing observations, and calculated by counting X-ray events (68% upper confidence limit) for each science energy band
flux_aper90_lolim double[6] ergs s-1 cm-2 aperture-corrected net energy flux inferred from the PSF 90% ECF aperture, best estimate derived from the longest block of a multi-band, flux-ordered Bayesian Block analysis of the contributing observations, and calculated by counting X-ray events (68% lower confidence limit) for each science energy band
flux_aper_avg double[6] ergs s-1 cm-2 aperture-corrected net energy flux inferred from the source region aperture, averaged over all contributing observations, and calculated by counting X-ray events for each science energy band
flux_aper_avg_hilim double[6] ergs s-1 cm-2 aperture-corrected net energy flux inferred from the source region aperture, averaged over all contributing observations, and calculated by counting X-ray events (68% upper confidence limit) for each science energy band
flux_aper_avg_lolim double[6] ergs s-1 cm-2 aperture-corrected net energy flux inferred from the source region aperture, averaged over all contributing observations, and calculated by counting X-ray events (68% lower confidence limit) for each science energy band
flux_aper_hilim double[6] ergs s-1 cm-2 aperture-corrected net energy flux inferred from the source region aperture, best estimate derived from the longest block of a multi-band, flux-ordered Bayesian Block analysis of the contributing observations, and calculated by counting X-ray events (68% upper confidence limit) for each science energy band
flux_aper_lolim double[6] ergs s-1 cm-2 aperture-corrected net energy flux inferred from the source region aperture, best estimate derived from the longest block of a multi-band, flux-ordered Bayesian Block analysis of the contributing observations, and calculated by counting X-ray events (68% lower confidence limit) for each science energy band
flux_bb double ergs s-1 cm-2 net integrated 0.5-7.0 keV energy flux of the best fitting absorbed black body model spectrum to the source region aperture PI spectrum
flux_bb_aper double[6] ergs s-1 cm-2 source region aperture model energy flux inferred from the canonical absorbed black body model [NH = NH(Gal); kT = 0.75 keV] for each science energy band
flux_bb_aper90 double[6] ergs s-1 cm-2 PSF 90% ECF aperture model energy flux inferred from the canonical absorbed black body model [NH = NH(Gal); kT = 0.75 keV] for each science energy band
flux_bb_aper90_hilim double[6] ergs s-1 cm-2 PSF 90% ECF aperture model energy flux inferred from the canonical absorbed black body model [NH = NH(Gal); kT = 0.75 keV] (68% upper confidence limit) for each science energy band
flux_bb_aper90_lolim double[6] ergs s-1 cm-2 PSF 90% ECF aperture model energy flux inferred from the canonical absorbed black body model [NH = NH(Gal); kT = 0.75 keV] (68% lower confidence limit) for each science energy band
flux_bb_aper_hilim double[6] ergs s-1 cm-2 source region aperture model energy flux inferred from the canonical absorbed black body model [NH = NH(Gal); kT = 0.75 keV] (68% upper confidence limit) for each science energy band
flux_bb_aper_lolim double[6] ergs s-1 cm-2 source region aperture model energy flux inferred from the canonical absorbed black body model [NH = NH(Gal); kT = 0.75 keV] (68% lower confidence limit) for each science energy band
flux_bb_hilim double ergs s-1 cm-2 net integrated 0.5-7.0 keV energy flux of the best fitting absorbed black body model spectrum to the source region aperture PI spectrum (68% upper confidence limit)
flux_bb_lolim double ergs s-1 cm-2 net integrated 0.5-7.0 keV energy flux of the best fitting absorbed black body model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
flux_brems double ergs s-1 cm-2 net integrated 0.5-7.0 keV energy flux of the best fitting absorbed bremsstrahlung model spectrum to the source region aperture PI spectrum
flux_brems_aper double[6] ergs s-1 cm-2 source region aperture model energy flux inferred from the canonical absorbed bremsstrahlung model [NH = NH(Gal); kT = 3.5 keV] for each science energy band
flux_brems_aper90 double[6] ergs s-1 cm-2 PSF 90% ECF aperture model energy flux inferred from the canonical absorbed bremsstrahlung model [NH = NH(Gal); kT = 3.5 keV] for each science energy band
flux_brems_aper90_hilim double[6] ergs s-1 cm-2 PSF 90% ECF aperture model energy flux inferred from the canonical absorbed bremsstrahlung model [NH = NH(Gal); kT = 3.5 keV] (68% upper confidence limit) for each science energy band
flux_brems_aper90_lolim double[6] ergs s-1 cm-2 PSF 90% ECF aperture model energy flux inferred from the canonical absorbed bremsstrahlung model [NH = NH(Gal); kT = 3.5 keV] (68% lower confidence limit) for each science energy band
flux_brems_aper_hilim double[6] ergs s-1 cm-2 source region aperture model energy flux inferred from the canonical absorbed bremsstrahlung model [NH = NH(Gal); kT = 3.5 keV] (68% upper confidence limit) for each science energy band
flux_brems_aper_lolim double[6] ergs s-1 cm-2 source region aperture model energy flux inferred from the canonical absorbed bremsstrahlung model [NH = NH(Gal); kT = 3.5 keV] (68% lower confidence limit) for each science energy band
flux_brems_hilim double ergs s-1 cm-2 net integrated 0.5-7.0 keV energy flux of the best fitting absorbed bremsstrahlung model spectrum to the source region aperture PI spectrum (68% upper confidence limit)
flux_brems_lolim double ergs s-1 cm-2 net integrated 0.5-7.0 keV energy flux of the best fitting absorbed bremsstrahlung model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
flux_powlaw double ergs s-1 cm-2 net integrated 0.5-7.0 keV energy flux of the best fitting absorbed power-law model spectrum to the source region aperture PI spectrum
flux_powlaw_aper double[6] ergs s-1 cm-2 source region aperture model energy flux inferred from the canonical absorbed power law model [NH = NH(Gal); γ = 2.0] for each science energy band
flux_powlaw_aper90 double[6] ergs s-1 cm-2 PSF 90% ECF aperture model energy flux inferred from the canonical absorbed power law model [NH = NH(Gal); γ = 2.0] for each science energy band
flux_powlaw_aper90_hilim double[6] ergs s-1 cm-2 PSF 90% ECF aperture model energy flux inferred from the canonical absorbed power law model [NH = NH(Gal); γ = 2.0] (68% upper confidence limit) for each science energy band
flux_powlaw_aper90_lolim double[6] ergs s-1 cm-2 PSF 90% ECF aperture model energy flux inferred from the canonical absorbed power law model [NH = NH(Gal); γ = 2.0] (68% lower confidence limit) for each science energy band
flux_powlaw_aper_hilim double[6] ergs s-1 cm-2 source region aperture model energy flux inferred from the canonical absorbed power law model [NH = NH(Gal); γ = 2.0] (68% upper confidence limit) for each science energy band
flux_powlaw_aper_lolim double[6] ergs s-1 cm-2 source region aperture model energy flux inferred from the canonical absorbed power law model [NH = NH(Gal); γ = 2.0] (68% lower confidence limit) for each science energy band
flux_powlaw_hilim double ergs s-1 cm-2 net integrated 0.5-7.0 keV energy flux of the best fitting absorbed power-law model spectrum to the source region aperture PI spectrum (68% upper confidence limit)
flux_powlaw_lolim double ergs s-1 cm-2 net integrated 0.5-7.0 keV energy flux of the best fitting absorbed power-law model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
gal_b double deg source position, Galactic latitude (equinox J2000.0, epoch J2000.0)
gal_l double deg source position, galactic longitude (equinox J2000.0, epoch J2000.0)
hard_hm double ACIS hard (2.0-7.0 keV) - medium (1.2-2.0 keV) energy band hardness ratio
hard_hm_hilim double ACIS hard (2.0-7.0 keV) - medium (1.2-2.0 keV) energy band hardness ratio (68% upper confidence limit)
hard_hm_lolim double ACIS hard (2.0-7.0 keV) - medium (1.2-2.0 keV) energy band hardness ratio (68% lower confidence limit)
hard_hs double ACIS hard (2.0-7.0 keV) - soft (0.5-1.2 keV) energy band hardness ratio
hard_hs_hilim double ACIS hard (2.0-7.0 keV) - soft (0.5-1.2 keV) energy band hardness ratio (68% upper confidence limit)
hard_hs_lolim double ACIS hard (2.0-7.0 keV) - soft (0.5-1.2 keV) energy band hardness ratio (68% lower confidence limit)
hard_ms double ACIS medium (1.2-2.0 keV) - soft (0.5-1.2 keV) energy band hardness ratio
hard_ms_hilim double ACIS medium (1.2-2.0 keV) - soft (0.5-1.2 keV) energy band hardness ratio (68% upper confidence limit)
hard_ms_lolim double ACIS medium (1.2-2.0 keV) - soft (0.5-1.2 keV) energy band hardness ratio (68% lower confidence limit)
hrc_hetg_num integer total number of HRC/HETG observations contributing to the Master Sources Table record of the source
hrc_hetg_time double total exposure time (seconds of good time) for all HRC/HETG observations contributing to the Master Sources Table record of the source
hrc_letg_num integer total number of HRC/LETG observations contributing to the Master Sources Table record of the source
hrc_letg_time double total exposure time (seconds of good time) for all HRC/LETG observations contributing to the Master Sources Table record of the source
hrc_num integer total number of HRC imaging observations contributing to the Master Sources Table record of the source
hrc_time double total exposure time (seconds of good time) for all HRC imaging observations contributing to the Master Sources Table record of the source
kp_intra_prob double[6] intra-observation Kuiper's test variability probability (highest value across all observations); ACIS for each science energy band
ks_intra_prob double[6] intra-observation Kolmogorov-Smirnov test variability probability (highest value across all observations) for each science energy band
likelihood double highest detection log-likelihood across all stacked observations and science energy bands
likelihood_class string highest detection likelihood classification across all stacked observations and science energy bands
major_axis double[6] arcseconds 1σ radius along the major axis of the ellipse defining the deconvolved source extent for each science energy band
major_axis_hilim double[6] arcseconds 1σ radius along the major axis of the ellipse defining the deconvolved source extent (68% upper confidence limit) for each science energy band
major_axis_lolim double[6] arcseconds 1σ radius along the major axis of the ellipse defining the deconvolved source extent (68% lower confidence limit) for each science energy band
man_add_flag Boolean source was manually added in the catalog via human review
man_inc_flag Boolean source was manually included in the catalog via human review (detection was rejected by automated criteria)
man_match_flag Boolean source detections were manually matched between overlapping stacked observations via human review
man_pos_flag Boolean best fit source position was manually modified via human review
man_reg_flag Boolean source region parameters (dimensions, initial guess position input to the Maximum Likelihood Estimator fit) were manually modified via human review
minor_axis double[6] arcseconds 1σ radius along the minor axis of the ellipse defining the deconvolved source extent for each science energy band
minor_axis_hilim double[6] arcseconds 1σ radius along the minor axis of the ellipse defining the deconvolved source extent (68% upper confidence limit) for each science energy band
minor_axis_lolim double[6] arcseconds 1σ radius along the minor axis of the ellipse defining the deconvolved source extent (68% lower confidence limit) for each science energy band
name string source name in the form "2CXO Jhhmmss.s{+|-}ddmmss" [Chandra source names use the ICRS position to an accuracy of 0.1s in RA and 1.0s in Dec.]
nh_gal double HI atoms 1020 cm-2 Galactic NH column density in direction of source
phot_nsrcs long number of sources simultaneously fit to compute aperture photometry quantitites
photflux_aper double[6] photons s-1 cm-2 aperture-corrected net photon flux inferred from the source region aperture, best estimate derived from the longest block of a multi-band, flux-ordered Bayesian Block analysis of the contributing observations, and calculated by counting X-ray events for each science energy band
photflux_aper90 double[6] photons s-1 cm-2 aperture-corrected net photon flux inferred from the PSF 90% ECF aperture, best estimate derived from the longest block of a multi-band, flux-ordered Bayesian Block analysis of the contributing observations, and calculated by counting X-ray events for each science energy band
photflux_aper90_avg double[6] photons s-1 cm-2 aperture-corrected net photon flux inferred from the PSF 90% ECF aperture, averaged over all contributing observations, and calculated by counting X-ray events for each science energy band
photflux_aper90_avg_hilim double[6] photons s-1 cm-2 aperture-corrected net photon flux inferred from the PSF 90% ECF aperture, averaged over all contributing observations, and calculated by counting X-ray events (68% upper confidence limit) for each science energy band
photflux_aper90_avg_lolim double[6] photons s-1 cm-2 aperture-corrected net photon flux inferred from the PSF 90% ECF aperture, averaged over all contributing observations, and calculated by counting X-ray events (68% lower confidence limit) for each science energy band
photflux_aper90_hilim double[6] photons s-1 cm-2 aperture-corrected net photon flux inferred from the PSF 90% ECF aperture, best estimate derived from the longest block of a multi-band, flux-ordered Bayesian Block analysis of the contributing observations, and calculated by counting X-ray events (68% upper confidence limit) for each science energy band
photflux_aper90_lolim double[6] photons s-1 cm-2 aperture-corrected net photon flux inferred from the PSF 90% ECF aperture, best estimate derived from the longest block of a multi-band, flux-ordered Bayesian Block analysis of the contributing observations, and calculated by counting X-ray events (68% lower confidence limit) for each science energy band
photflux_aper_avg double[6] photons s-1 cm-2 aperture-corrected net photon flux inferred from the source region aperture, averaged over all contributing observations, and calculated by counting X-ray events for each science energy band
photflux_aper_avg_hilim double[6] photons s-1 cm-2 aperture-corrected net photon flux inferred from the source region aperture, averaged over all contributing observations, and calculated by counting X-ray events (68% upper confidence limit) for each science energy band
photflux_aper_avg_lolim double[6] photons s-1 cm-2 aperture-corrected net photon flux inferred from the source region aperture, averaged over all contributing observations, and calculated by counting X-ray events (68% lower confidence limit) for each science energy band
photflux_aper_hilim double[6] photons s-1 cm-2 aperture-corrected net photon flux inferred from the source region aperture, best estimate derived from the longest block of a multi-band, flux-ordered Bayesian Block analysis of the contributing observations, and calculated by counting X-ray events (68% upper confidence limit) for each science energy band
photflux_aper_lolim double[6] photons s-1 cm-2 aperture-corrected net photon flux inferred from the source region aperture, best estimate derived from the longest block of a multi-band, flux-ordered Bayesian Block analysis of the contributing observations, and calculated by counting X-ray events (68% lower confidence limit) for each science energy band
pileup_flag Boolean ACIS pile-up fraction exceeds ~10% in all observations; source properties may be affected
pos_angle double[6] deg position angle (referenced from local true north) of the major axis of the ellipse defining the deconvolved source extent for each science energy band
pos_angle_hilim double[6] deg position angle (referenced from local true north) of the major axis of the ellipse defining the deconvolved source extent (68% upper confidence limit) for each science energy band
pos_angle_lolim double[6] deg position angle (referenced from local true north) of the major axis of the ellipse defining the deconvolved source extent (68% lower confidence limit) for each science energy band
powlaw_ampl double amplitude of the best fitting absorbed power-law model spectrum to the source region aperture PI spectrum
powlaw_ampl_hilim double amplitude of the best fitting absorbed power-law model spectrum to the source region aperture PI spectrum (68% upper confidence limit)
powlaw_ampl_lolim double amplitude of the best fitting absorbed power-law model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
powlaw_ampl_rhat double amplitude convergence criterion of the best fitting absorbed power-law model spectrum to the source region aperture PI spectrum
powlaw_gamma double photon index, defined as FE ∝ E, of the best fitting absorbed power-law model spectrum to the source region aperture PI spectrum
powlaw_gamma_hilim double photon index, defined as FE ∝ E, of the best fitting absorbed power-law model spectrum to the source region aperture PI spectrum (68% upper confidence limit)
powlaw_gamma_lolim double photon index, defined as FE ∝ E, of the best fitting absorbed power-law model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
powlaw_gamma_rhat double photon index convergence criterion of the best fitting absorbed power-law model spectrum to the source region aperture PI spectrum
powlaw_nh double HI atoms 1020 cm-2 NH column density of the best fitting absorbed power-law model spectrum to the source region aperture PI spectrum
powlaw_nh_hilim double HI atoms 1020 cm-2 NH column density of the best fitting absorbed power-law model spectrum to the source region aperture PI spectrum (68% upper confidence limit)
powlaw_nh_lolim double HI atoms 1020 cm-2 NH column density of the best fitting absorbed power-law model spectrum to the source region aperture PI spectrum (68% lower confidence limit)
powlaw_nh_rhat double NH column density convergence criterion of the best fitting absorbed power-law model spectrum to the source region aperture PI spectrum
powlaw_stat double χ2 statistic per degree of freedom of the best fitting absorbed power-law model spectrum to the source region aperture PI spectrum
ra double deg source position, ICRS right ascension
sat_src_flag Boolean source is saturated in all observations; source properties are unreliable
significance double highest flux significance across all stacked observations and science energy bands
src_area double[6] sq. arcseconds area of the deconvolved source extent ellipse, or area of the source polygon for extended sources for each science energy band
streak_src_flag Boolean source is located on an ACIS readout streak in all observations; source properties may be affected
var_flag Boolean source displays flux variability within one or more observations, or between observations, in one or more energy bands
var_inter_hard_flag Boolean source hardness ratios are statistically inconsistent between two or more observations
var_inter_hard_prob_hm double inter-observation ACIS hard (2.0-7.0 keV) - medium (1.2-2.0 keV) energy band hardness ratio variability probability
var_inter_hard_prob_hs double inter-observation ACIS hard (2.0-7.0 keV) - soft (0.5-1.2 keV) energy band hardness ratio variability probability
var_inter_hard_prob_ms double inter-observation ACIS medium (1.2-2.0 keV) - soft (0.5-1.2 keV) energy band hardness ratio variability probability
var_inter_index integer[6] inter-observation variability index in the range [0, 10]: indicates whether the source region photon flux is constant between observations for each science energy band
var_inter_prob double[6] inter-observation variability probability, calculated from the chi^2 distribution of the photon fluxes of the individual observations for each science energy band
var_inter_sigma double[6] photons s-1 cm-2 inter-observation flux variability standard deviation; the spread of the individual observation photon fluxes about the error weighted mean for each science energy band
var_inter_sigma_prob_hm double inter-observation ACIS hard (2.0-7.0 keV) - medium (1.2-2.0 keV) energy band hardness ratio variability standard deviation
var_inter_sigma_prob_hs double inter-observation ACIS hard (2.0-7.0 keV) - soft (0.5-1.2 keV) energy band hardness ratio variability standard deviation
var_inter_sigma_prob_ms double inter-observation ACIS medium (1.2-2.0 keV) - soft (0.5-1.2 keV) energy band hardness ratio variability standard deviation
var_intra_index integer[6] intra-observation Gregory-Loredo variability index in the range [0, 10]: indicates whether the source region photon flux is constant within an observation (highest value across all observations) for each science energy band
var_intra_prob double[6] intra-observation Gregory-Loredo variability probability (highest value across all observations) for each science energy band

Last modified: 1 October 2018
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