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1SXPS Catalogue: On-line Documentation

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  1. Summary / Quick-start information.
  2. Access & Usage.
  3. Catalogue contents.

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Summary / Quick-start information

Data included2004 Dec 12 — 2012 October 12
Sky coverage1905 square degrees
Typical Sensitivity
(0.3—10 keV)
3×10-13 erg cm-2 s-1 (single observation)
9×10-14 erg cm-2 s-1 (stacked images)
Typical position error5.5′′ (90% confidence radius, including systematics)
Detections585,443
Unique sources151,524
Variable sources28,906
Uncatalogued sources82,282
False positive rateFlag=Good0.3%
Flag=Good/Reasonable1%
Flag=Good/Reasonable/Poor10%

Table 1. Summary details of the 1SXPS catalogue.

The 1SXPS catalogue covers 1905 square degrees on the sky and contains position, fluxes, spectral details and variability information for 151,524 X-ray point sources detected by the Swift X-ray Telescope between 2004 Dec 12 and 2012 October 12. Each source has a detection flag which indicates how likely it is to be a real astrophysical object. Table 1 shows the false positive rate as a function of flag and other summary information.

The catalogue, which is described in full in Evans et al (2014) employs an iterative sliding-cell detection procedure, which is significantly more sensitive than previous XRT catalogues. This process is described in detail in the paper and summarised here. Extensive verification has also been carried out to ascertain the reliability and completeness of the catalogue and the various products. We also cross correlated this catalogue with a number of existing catalogues and databases.

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Data Access and Usage

The catalogue can be downloaded as a FITS file, CSV file or SQL dump or queried through this page. Not all columns contain values for each entry in the tables, for example, in the Sources table, only sources for which a spectral fit exists have entries in the Fitted* fields. In the CSV files, such empty entries are literally empty; in the FITS and SQL files these entries are NULL.

If you use data from this catalogue in your work, please cite Evans et al. (2014) and in the acknowledgements section of your publication, please state:

This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester.

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Catalogue Contents

There are four tables available for download:

Sources
This is the main catalogue table, the only one which is available in Vizier. This contains the details of the 151,524 unique sources in the catalogue.
Detections
This contains details of the individual detections in each dataset and energy band, of the sources.
Datasets
This contains details of the individual datasets (observations and stacked images) of which the catalogue is composed.
Cross correlations
This contains details of sources from external catalogues which are positionally coincident with 1SXPS sources.

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Sources Table

The Sources table is the main catalogue table, and gives details of each unique source identified in the catalogue. There are 1/2 columns in this table in total, so for ease of consideration we have grouped them into the following categories:

Identifiers

Name
The unique IAU format unique source name, of the form: 1SXPS JHHMMSS.S+ddmmss

[Hide identifier columns | Back to Sources table | Back to top | 1SXPS index]


Position information

RA
The Right Ascension (J2000) of the source, taken from the individual detection with the smallest error.
Decl
The declination (J2000) of the source, taken from the individual detection with the smallest error.
Err90
The 90% confidence radial position error on the source position, taken from the individual detection with the smallest error. This includes the astrometric systematic error.
AstromType
This relates the provenance of the astrometry used to derive the source position.
  • 0: Astrometry from the Swift star trackers.
  • 1: Astrometry from rectification with 2MASS.
l
The Galactic longitude in degrees of the best position of the source.
b
The Galactic latitude in degrees of the best position of the source.
OffAxis
The mean distance angle (in arc minutes) of the source from the centre of the XRT detector averaged over all observations in which the source was detected and inside the XRT field of view. There is a handful of sources for which this value is -1. This indicates that the source centre was never in the field of view, that is, the detection and centroid was based on the wings of the PSF that extended into the field of view.

[Hide position columns | Back to Sources table | Back to top | 1SXPS index]


Exposure information

Exposure
The total exposure at the location of the source in seconds, including datasets in which the source was not detected.
StartDate
The UT date and time of the start of the first observation of the source location (regardless of whether the source was detected).
StopDate
The UT date and time of the end of the last observation of the source location (regardless of whether the source was detected).
NumObs
The total number of datasets (observations+stacked images) which cover the location of the source, including those in which the source was not detected.
NumDetObs
The number of datasets (observations+stacked images) in which the source was detected.

[Hide exposure columns | Back to Sources table | Back to top | 1SXPS index]


Flag information

DetFlag
The best detection flag from all detections of the source. This is a numerical value, normally 0 (=Good), 1 (=Reasonable) or 2 (=Poor) For sources which lie inside a region which was identified in the manual screening stage as containing artefacts the flag values are 8, 9 and 10 for the three categories. Those in a region manually marked as containing diffuse emission have flag values of 16,17 and 18. In the case where the flag has a value >2 the Good, Reasonable or Poor definitions indicate the strength of the detection, however the source is highly likely nonetheless to be spurious.
Fieldflag
The best field flag from all detections of the source. This can be either Good (=0) or Flagged (=1 or 2). The latter indicates that there are artefacts (flag=1) and/or extended emission (flag=2) in the field which may affect the flux levels of the point sources detected.
DetFlag_band0
The best total-band (0.3—10 keV) detection flag from all detections of the source.
DetFlag_band1
The best soft-band (0.3—1 keV) detection flag from all detections of the source.
DetFlag_band2
The best medium-band (1—2 keV) detection flag from all detections of the source.
DetFlag_band3
The best hard-band (2—10 keV) detection flag from all detections of the source.

[Hide flag columns | Back to Sources table | Back to top | 1SXPS index]


Count-rate information

Rate_band0
The time-averaged total-band (0.3—10 keV) count-rate of the source, in counts per second.
Rate_band0_pos
The 1-σ positive error on the time-averaged total-band (0.3—10 keV) count-rate of the source. If more than 30 events were detected in this band (after background subtraction) this is the Poisson error, otherwise it is calculated from the Bayesian method of Kraft, Burrows & Nousek (1991).
Rate_band0_neg
The 1-σ negative error on the time-averaged total-band (0.3—10 keV) count-rate of the source. If more than 30 events were detected in this band (after background subtraction) this is the Poisson error, otherwise it is calculated from the Bayesian method of Kraft, Burrows & Nousek (1991).
Rate_band1
The time-averaged soft-band (0.3—1 keV) count-rate of the source, in counts per second.
Rate_band1_pos
The 1-σ positive error on the time-averaged soft-band (0.3—1 keV) count-rate of the source.
Rate_band1_neg
The 1-σ negative error on the time-averaged soft-band (0.3—1 keV) count-rate of the source.
Rate_band2
The time-averaged medium-band (1—2 keV) count-rate of the source, in counts per second.
Rate_band2_pos
The 1-σ positive error on the time-averaged medium-band (1—2 keV) count-rate of the source.
Rate_band2_neg
The 1-σ negative error on the time-averaged medium-band (1—2 keV) count-rate of the source.
Rate_band3
The time-averaged hard-band (2—10 keV) count-rate of the source, in counts per second.
Rate_band3_pos
The 1-σ positive error on the time-averaged hard-band (2—10 keV) count-rate of the source.
Rate_band3_neg
The 1-σ negative error on the time-averaged hard-band (2—10 keV) count-rate of the source.
Counts_band0
The total number of events (not background subtracted or exposure corrected) in the total-band (0.3—10 keV) image, in the source extraction region for this source. This is found by summing the counts in the individual observations of the location, not from the stacked image.
Counts_band1
The total number of events (not background subtracted or exposure corrected) in the soft-band (0.3—1 keV) image, in the source extraction region for this source.
Counts_band2
The total number of events (not background subtracted or exposure corrected) in the medium-band (1—2 keV) image, in the source extraction region for this source.
Counts_band3
The total number of events (not background subtracted or exposure corrected) in the hard-band (2—10 keV) image, in the source extraction region for this source.
BGCounts_band0
The sum of the background map in the in the total-band (0.3—10 keV) source extraction region for this source. This is found by summing the maps in the individual observations of the location, not from the stacked image.
BGCounts_band1
The sum of the background map in the in the soft-band (0.3—1 keV) image, in the source extraction region for this source.
BGCounts_band2
The sum of the background map in the in the medium-band (1—2 keV) image, in the source extraction region for this source.
BGCounts_band3
The sum of the background map in the in the hard-band (2—10 keV) image, in the source extraction region for this source.
CF_band0
The count-rate correction factor in the total band (0.3—10 keV). The count-rate correction factor. This corrects for vignetting, bad columns pile-up and the finite radius over which counts were extracted.
CF_band1
The count-rate correction factor in the soft band (0.3—1 keV). The count-rate correction factor.
CF_band2
The count-rate correction factor in the medium band (1—2 keV). The count-rate correction factor.
CF_band3
The count-rate correction factor in the hard band (2—10 keV). The count-rate correction factor.
HR1
The HR1 hardness ratio = (M-S)/(M+S) where M and S are the medium (1—2 keV) and soft (0.3—1 keV) band count-rates. If both bands had more than 100 photons and an SNR of at least 2 this was calculted simply from this equation, otherwise the Bayesian approach of Park et al. (2006) was employed.
HR1_pos
The 1-σ positive error on HR1. In a small number of cases where the Bayesian approach of Park et al. (2006) was used to derive HR1, the mean HR value lay outside the 1-σ confidence interval. In these cases the HR1_pos error may be negative.
HR1_neg
The 1-σ negative error on HR1. In a small number of cases where the Bayesian approach of Park et al. (2006) was used to derive HR1, the mean HR value lay outside the 1-σ confidence interval. In these cases the HR1_neg error may be positive.
HR2
The HR2 hardness ratio = (H-M)/(H+M) where H and M are the hard (2—10 keV) and medium (1—2 keV) band count-rates. If both bands had more than 100 photons and an SNR of at least 2 this was calculted simply from this equation, otherwise the Bayesian approach of Park et al. (2006) was employed.
HR2_pos
The 1-σ positive error on HR2. In a small number of cases where the Bayesian approach of Park et al. (2006) was used to derive HR2, the mean HR value lay outside the 1-σ confidence interval. In these cases the HR2_pos error may be negative.
HR2_neg
The 1-σ negative error on HR2. In a small number of cases where the Bayesian approach of Park et al. (2006) was used to derive HR2, the mean HR value lay outside the 1-σ confidence interval. In these cases the HR2_neg error may be positive.

[Hide count-rate columns | Back to Sources table | Back to top | 1SXPS index]


Variability information

PvarPchiSnapshot_band0
The probability that the source is constant within a single snapshot in the total band (0.3—10 keV), as derived from the Pearson's χ2 test. The minimum recordable value for this is 1.1×10-16 so values of 0 mean <1.1×10-16.
PvarPchiSnapshot_band1
The probability that the source is constant within a single snapshot in the soft band (0.3—1 keV), as derived from the Pearson's χ2 test.
PvarPchiSnapshot_band2
The probability that the source is constant within a single snapshot in the medium band (1—2 keV), as derived from the Pearson's χ2 test.
PvarPchiSnapshot_band3
The probability that the source is constant within a single snapshot in the hard band (2—10 keV), as derived from the Pearson's χ2 test.
PvarPchiObsID_band0
The probability that the source is constant between observations in the total band (0.3—10 keV), as derived from the Pearson's χ2 test.
PvarPchiObsID_band1
The probability that the source is constant between observations in the soft band (0.3—1 keV), as derived from the Pearson's χ2 test.
PvarPchiObsID_band2
The probability that the source is constant between observations in the medium band (1—2 keV), as derived from the Pearson's χ2 test.
PvarPchiObsID_band3
The probability that the source is constant between observations in the hard band (2—10 keV), as derived from the Pearson's χ2 test.

[Hide variability columns | Back to Sources table | Back to top | 1SXPS index]


Spectral/Flux information

GalNH
The Galactic absorption column density (in cm-2) in the direction of the source, determined from Willingale et al. (2013).
whichPow
Which of the available estimates of the power-law spectral ECF and fluxes is given in the summary fields:
  • 0: Fixed spectrum
  • 1: HR-interpolated
  • 2: Fitted spectrum
whichAPEC
Which of the available estimates of the APEC spectral ECF and fluxes is given in the summary fields:
  • 0: Fixed spectrum
  • 1: HR-interpolated
  • 2: Fitted spectrum
PowECFO
The counts-to-observed-flux (0.3—10 keV) conversion factor (in erg cm-2 ct-1), assuming the power-law spectrum indicated by the whichPow field.
PowECFU
The counts-to-unabsorbed-flux (0.3—10 keV) conversion factor (in erg cm-2 ct-1), assuming the power-law spectrum indicated by the whichPow field.
PowFlux
The observed 0.3—10 keV flux (in erg cm-2 s-1), assuming the power-law spectrum indicated by the whichPow field.
PowFlux_pos
The 1-σ positive error on the observed 0.3—10 keV flux for the power-law spectrum indicated by the whichPow field. This is taken from the band0Rate_pos field multiplied by the PowECFO field, so does not include uncertainties in the spectral modelling.
PowFlux_neg
The 1-σ negative error on the observed 0.3—10 keV flux for the power-law spectrum indicated by the whichPow field. This is taken from the band0Rate_neg field multiplied by the PowECFO field, so does not include uncertainties in the spectral modelling.
PowPeakFlux
The maximum observed 0.3—10 keV flux (in erg cm-2 s-1) for the power-law spectrum indicated by the whichPow field. This is taken from the bin in the total-band per-snapshot light curve with the highest value, multiplied by the PowECFO field.
PowPeakFlux_pos
The 1-σ positive error on the maximum observed 0.3—10 keV flux for the power-law spectrum indicated by the whichPow field. This is taken from the bin in the total-band per-snapshot light curve with the highest value, multiplied by the PowECFO field, so does not include uncertainties in the spectral modelling.
PowPeakFlux_neg
The 1-σ negative error on the maximum observed 0.3—10 keV flux for the power-law spectrum indicated by the whichPow field. This is taken from the bin in the total-band per-snapshot light curve with the highest value, multiplied by the PowECFO field, so does not include uncertainties in the spectral modelling.
PowUnabsFlux
The unabsorbed 0.3—10 keV flux (in erg cm-2 s-1), assuming the power-law spectrum indicated by the whichPow field.
PowUnabsFlux_pos
The 1-σ positive error on the unabsorbed 0.3—10 keV flux for the power-law spectrum indicated by the whichPow field. This is taken from the band0Rate_pos field multiplied by the PowECFU field, so does not include uncertainties in the spectral modelling.
PowUnabsFlux_neg
The 1-σ negative error on the unabsorbed 0.3—10 keV flux for the power-law spectrum indicated by the whichPow field. This is taken from the band0Rate_neg field multiplied by the PowECFU field, so does not include uncertainties in the spectral modelling.
PowPeakUnabsFlux
The maximum unabsorbed 0.3—10 keV flux (in erg cm-2 s-1) for the power-law spectrum indicated by the whichPow field. This is taken from the bin in the total-band per-snapshot light curve with the highest value, multiplied by the PowECFU field.
PowPeakUnabsFlux_pos
The 1-σ positive error on the maximum unabsorbed 0.3—10 keV flux for the power-law spectrum indicated by the whichPow field. This is taken from the bin in the total-band per-snapshot light curve with the highest value, multiplied by the PowECFU field, so does not include uncertainties in the spectral modelling.
PowPeakUnabsFlux_neg
The 1-σ negative error on the maximum unabsorbed 0.3—10 keV flux for the power-law spectrum indicated by the whichPow field. This is taken from the bin in the total-band per-snapshot light curve with the highest value, multiplied by the PowECFU field, so does not include uncertainties in the spectral modelling.
APECECFO
The counts-to-observed-flux (0.3—10 keV) conversion factor (in erg cm-2 ct-1), assuming the APEC spectrum indicated by the whichPow field.
APECECFU
The counts-to-unabsorbed-flux (0.3—10 keV) conversion factor (in erg cm-2 ct-1), assuming the APEC spectrum indicated by the whichPow field.
APECFlux
The observed 0.3—10 keV flux (in erg cm-2 s-1), assuming the APEC spectrum indicated by the whichPow field.
APECFlux_pos
The 1-σ positive error on the observed 0.3—10 keV flux for the APEC spectrum indicated by the whichPow field. This is taken from the band0Rate_pos field multiplied by the APECECFO field, so does not include uncertainties in the spectral modelling.
APECFlux_neg
The 1-σ negative error on the observed 0.3—10 keV flux for the APEC spectrum indicated by the whichPow field. This is taken from the band0Rate_neg field multiplied by the APECECFO field, so does not include uncertainties in the spectral modelling.
APECPeakFlux
The maximum observed 0.3—10 keV flux (in erg cm-2 s-1) for the APEC spectrum indicated by the whichPow field. This is taken from the bin in the total-band per-snapshot light curve with the highest value, multiplied by the APECECFO field.
APECPeakFlux_pos
The 1-σ positive error on the maximum observed 0.3—10 keV flux for the APEC spectrum indicated by the whichPow field. This is taken from the bin in the total-band per-snapshot light curve with the highest value, multiplied by the APECECFO field, so does not include uncertainties in the spectral modelling.
APECPeakFlux_neg
The 1-σ negative error on the maximum observed 0.3—10 keV flux for the APEC spectrum indicated by the whichPow field. This is taken from the bin in the total-band per-snapshot light curve with the highest value, multiplied by the APECECFO field, so does not include uncertainties in the spectral modelling.
APECUnabsFlux
The unabsorbed 0.3—10 keV flux (in erg cm-2 s-1), assuming the APEC spectrum indicated by the whichPow field.
APECUnabsFlux_pos
The 1-σ positive error on the unabsorbed 0.3—10 keV flux for the APEC spectrum indicated by the whichPow field. This is taken from the band0Rate_pos field multiplied by the APECECFU field, so does not include uncertainties in the spectral modelling.
APECUnabsFlux_neg
The 1-σ negative error on the unabsorbed 0.3—10 keV flux for the APEC spectrum indicated by the whichPow field. This is taken from the band0Rate_neg field multiplied by the APECECFU field, so does not include uncertainties in the spectral modelling.
APECPeakUnabsFlux
The maximum unabsorbed 0.3—10 keV flux (in erg cm-2 s-1) for the APEC spectrum indicated by the whichPow field. This is taken from the bin in the total-band per-snapshot light curve with the highest value, multiplied by the APECECFU field.
APECPeakUnabsFlux_pos
The 1-σ positive error on the maximum unabsorbed 0.3—10 keV flux for the APEC spectrum indicated by the whichPow field. This is taken from the bin in the total-band per-snapshot light curve with the highest value, multiplied by the APECECFU field, so does not include uncertainties in the spectral modelling.
APECPeakUnabsFlux_neg
The 1-σ negative error on the maximum unabsorbed 0.3—10 keV flux for the APEC spectrum indicated by the whichPow field. This is taken from the bin in the total-band per-snapshot light curve with the highest value, multiplied by the APECECFU field, so does not include uncertainties in the spectral modelling.
FixedPowECFO
The counts-to-observed-flux (0.3—10 keV) conversion factor (in erg cm-2 ct-1), assuming a power-law spectrum with a photon index of 1.7 absorbed by the Galactic column (from the GalNH field).
FixedPowECFU
The counts-to-unabsorbed-flux (0.3—10 keV) conversion factor (in erg cm-2 ct-1), assuming a power-law spectrum with a photon index of 1.7 absorbed by the Galactic column (from the GalNH field).
FixedPowFlux
The observed 0.3—10 keV flux (in erg cm-2 s-1), assuming a power-law spectrum with a photon index of 1.7 absorbed by the Galactic column (from the GalNH field).
FixedPowFlux_pos
The 1-σ positive error on the observed 0.3—10 keV flux for a power-law spectrum with a photon index of 1.7 absorbed by the Galactic column (from the GalNH field). This is taken from the band0Rate_pos field multiplied by the FixedPowECFO field, so does not include uncertainties in the spectral modelling.
FixedPowFlux_neg
The 1-σ negative error on the observed 0.3—10 keV flux for a power-law spectrum with a photon index of 1.7 absorbed by the Galactic column (from the GalNH field). This is taken from the band0Rate_neg field multiplied by the FixedPowECFO field, so does not include uncertainties in the spectral modelling.
FixedPowUnabsFlux
The unabsorbed 0.3—10 keV flux (in erg cm-2 s-1), assuming a power-law spectrum with a photon index of 1.7 absorbed by the Galactic column (from the GalNH field).
FixedPowUnabsFlux_pos
The 1-σ positive error on the unabsorbed 0.3—10 keV flux for a power-law spectrum with a photon index of 1.7 absorbed by the Galactic column (from the GalNH field). This is taken from the band0Rate_pos field multiplied by the FixedPowECFU field, so does not include uncertainties in the spectral modelling.
FixedPowUnabsFlux_neg
The 1-σ negative error on the unabsorbed 0.3—10 keV flux for a power-law spectrum with a photon index of 1.7 absorbed by the Galactic column (from the GalNH field). This is taken from the band0Rate_neg field multiplied by the FixedPowECFU field, so does not include uncertainties in the spectral modelling.
FixedAPECECFO
The counts-to-observed-flux (0.3—10 keV) conversion factor (in erg cm-2 ct-1), assuming an APEC spectrum with a temperature of 1 keV absorbed by the Galactic column (from the GalNH field).
FixedAPECECFU
The counts-to-unabsorbed-flux (0.3—10 keV) conversion factor (in erg cm-2 ct-1), assuming an APEC spectrum with a temperature of 1 keV absorbed by the Galactic column (from the GalNH field).
FixedAPECFlux
The observed 0.3—10 keV flux (in erg cm-2 s-1), assuming an APEC spectrum with a temperature of 1 keV absorbed by the Galactic column (from the GalNH field).
FixedAPECFlux_pos
The 1-σ positive error on the observed 0.3—10 keV flux for an APEC spectrum with a temperature of 1 keV absorbed by the Galactic column (from the GalNH field). This is taken from the band0Rate_pos field multiplied by the FixedAPECECFO field, so does not include uncertainties in the spectral modelling.
FixedAPECFlux_neg
The 1-σ negative error on the observed 0.3—10 keV flux for an APEC spectrum with a temperature of 1 keV absorbed by the Galactic column (from the GalNH field). This is taken from the band0Rate_neg field multiplied by the FixedAPECECFO field, so does not include uncertainties in the spectral modelling.
FixedAPECUnabsFlux
The unabsorbed 0.3—10 keV flux (in erg cm-2 s-1), assuming an APEC spectrum with a temperature of 1 keV absorbed by the Galactic column (from the GalNH field).
FixedAPECUnabsFlux_pos
The 1-σ positive error on the unabsorbed 0.3—10 keV flux for an APEC spectrum with a temperature of 1 keV absorbed by the Galactic column (from the GalNH field). This is taken from the band0Rate_pos field multiplied by the FixedAPECECFU field, so does not include uncertainties in the spectral modelling.
FixedAPECUnabsFlux_neg
The 1-σ negative error on the unabsorbed 0.3—10 keV flux for an APEC spectrum with a temperature of 1 keV absorbed by the Galactic column (from the GalNH field). This is taken from the band0Rate_neg field multiplied by the FixedAPECECFU field, so does not include uncertainties in the spectral modelling.
InterpPowECFO
The counts-to-observed-flux (0.3—10 keV) conversion factor (in erg cm-2 ct-1), derived from the hardness ratios of the source, interpolated on a look-up table of power-law spectra.
InterpPowECFU
The counts-to-unabsorbed-flux (0.3—10 keV) conversion factor (in erg cm-2 ct-1), derived from the hardness ratios of the source, interpolated on a look-up table of power-law spectra.
InterpPowFlux
The observed 0.3—10 keV flux (in erg cm-2 s-1), derived from the hardness ratios of the source, interpolated on a look-up table of power-law spectra.
InterpPowFlux_pos
The 1-σ positive error on the observed 0.3—10 keV flux derived from the hardness ratios of the source, interpolated on a look-up table of power-law spectra. This is taken from the band0Rate_pos field multiplied by the InterpPowECFO field, so does not include uncertainties in the spectral modelling.
InterpPowFlux_neg
The 1-σ negative error on the observed 0.3—10 keV flux derived from the hardness ratios of the source, interpolated on a look-up table of power-law spectra. This is taken from the band0Rate_neg field multiplied by the InterpPowECFO field, so does not include uncertainties in the spectral modelling.
InterpPowUnabsFlux
The unabsorbed 0.3—10 keV flux (in erg cm-2 s-1), derived from the hardness ratios of the source, interpolated on a look-up table of power-law spectra.
InterpPowUnabsFlux_pos
The 1-σ positive error on the unabsorbed 0.3—10 keV flux derived from the hardness ratios of the source, interpolated on a look-up table of power-law spectra. This is taken from the band0Rate_pos field multiplied by the InterpPowECFU field, so does not include uncertainties in the spectral modelling.
InterpPowUnabsFlux_neg
The 1-σ negative error on the unabsorbed 0.3—10 keV flux derived from the hardness ratios of the source, interpolated on a look-up table of power-law spectra. This is taken from the band0Rate_neg field multiplied by the InterpPowECFU field, so does not include uncertainties in the spectral modelling.
InterpPowNH
The absorption column (in cm-2) of the spectrum of the source derived from the hardness ratios of the source, interpolated on a look-up table of power-law spectra.
InterpPowNH_pos
The 1-σ positive error absorption column of the spectrum of the source derived from the hardness ratios of the source, interpolated on a look-up table of power-law spectra. A value of -1 indicates that this error could not be constrained.
InterpPowNH_neg
The 1-σ negative error absorption column of the spectrum of the source derived from the hardness ratios of the source, interpolated on a look-up table of power-law spectra. A value of +1 indicates that this error could not be constrained.
InterpPowGamma
The power-law photon index of the spectrum of the source derived from the hardness ratios of the source, interpolated on a look-up table of power-law spectra.
InterpPowGamma_pos
The 1-σ positive error on the power-law photon index of the spectrum of the source derived from the hardness ratios of the source, interpolated on a look-up table of power-law spectra. A value of -1 indicates that this error could not be constrained.
InterpPowGamma_neg
The 1-σ negative error on the power-law photon index of the spectrum of the source derived from the hardness ratios of the source, interpolated on a look-up table of power-law spectra. A value of +1 indicates that this error could not be constrained.
InterpAPECECFO
The counts-to-observed-flux (0.3—10 keV) conversion factor (in erg cm-2 ct-1), derived from the hardness ratios of the source, interpolated on a look-up table of APEC spectra.
InterpAPECECFU
The counts-to-unabsorbed-flux (0.3—10 keV) conversion factor (in erg cm-2 ct-1), derived from the hardness ratios of the source, interpolated on a look-up table of APEC spectra.
InterpAPECFlux
The observed 0.3—10 keV flux (in erg cm-2 s-1), derived from the hardness ratios of the source, interpolated on a look-up table of APEC spectra.
InterpAPECFlux_pos
The 1-σ positive error on the observed 0.3—10 keV flux derived from the hardness ratios of the source, interpolated on a look-up table of APEC spectra. This is taken from the band0Rate_pos field multiplied by the InterpAPECECFO field, so does not include uncertainties in the spectral modelling.
InterpAPECFlux_neg
The 1-σ negative error on the observed 0.3—10 keV flux derived from the hardness ratios of the source, interpolated on a look-up table of APEC spectra. This is taken from the band0Rate_neg field multiplied by the InterpAPECECFO field, so does not include uncertainties in the spectral modelling.
InterpAPECUnabsFlux
The unabsorbed 0.3—10 keV flux (in erg cm-2 s-1), derived from the hardness ratios of the source, interpolated on a look-up table of APEC spectra.
InterpAPECUnabsFlux_pos
The 1-σ positive error on the unabsorbed 0.3—10 keV flux derived from the hardness ratios of the source, interpolated on a look-up table of APEC spectra. This is taken from the band0Rate_pos field multiplied by the InterpAPECECFU field, so does not include uncertainties in the spectral modelling.
InterpAPECUnabsFlux_neg
The 1-σ negative error on the unabsorbed 0.3—10 keV flux derived from the hardness ratios of the source, interpolated on a look-up table of APEC spectra. This is taken from the band0Rate_neg field multiplied by the InterpAPECECFU field, so does not include uncertainties in the spectral modelling.
InterpAPECNH
The absorption column (in cm-2) of the spectrum of the source derived from the hardness ratios of the source, interpolated on a look-up table of APEC spectra.
InterpAPECNH_pos
The 1-σ positive error absorption column of the spectrum of the source derived from the hardness ratios of the source, interpolated on a look-up table of APEC spectra. A value of -1 indicates that this error could not be constrained.
InterpAPECNH_neg
The 1-σ negative error absorption column of the spectrum of the source derived from the hardness ratios of the source, interpolated on a look-up table of APEC spectra. A value of +1 indicates that this error could not be constrained.
InterpAPECkT
The APEC plasma temperature (in keV) of the spectrum of the source derived from the hardness ratios of the source, interpolated on a look-up table of APEC spectra.
InterpAPECkT_pos
The 1-σ positive error on the APEC plasma temperature of the spectrum of the source derived from the hardness ratios of the source, interpolated on a look-up table of APEC spectra. A value of -1 indicates that this error could not be constrained.
InterpAPECkT_neg
The 1-σ negative error on the APEC plasma temperature of the spectrum of the source derived from the hardness ratios of the source, interpolated on a look-up table of APEC spectra. A value of +1 indicates that this error could not be constrained.
P_pow
If the (HR1,HR2) values of the source lie inside the range allowed by the simple power-law spectrum, this field is 1. Otherwise it is the probability of obtaining the measured hardness ratios and errors if the true spectrum is that which gives (HR1,HR2) closest to the source's values.
P_APEC
If the (HR1,HR2) values of the source lie inside the range allowed by the simple APEC spectrum, this field is 1. Otherwise it is the probability of obtaining the measured hardness ratios and errors if the true spectrum is that which gives (HR1,HR2) closest to the source's values.
FittedPowECFO
The counts-to-observed-flux (0.3—10 keV) conversion factor (in erg cm-2 ct-1), from an automated power-law spectral fit to an automatically-extracted spectrum of the source.
FittedPowECFU
The counts-to-unabsorbed-flux (0.3—10 keV) conversion factor (in erg cm-2 ct-1), from an automated power-law spectral fit to an automatically-extracted spectrum of the source.
FittedPowFlux
The observed 0.3—10 keV flux (in erg cm-2 s-1), from an automated power-law spectral fit to an automatically-extracted spectrum of the source.
FittedPowFlux_pos
The 1-σ positive error on the observed 0.3—10 keV flux from an automated power-law spectral fit to an automatically-extracted spectrum of the source. This is taken from the band0Rate_pos field multiplied by the FittedPowECFO field, so does not include uncertainties in the spectral modelling.
FittedPowFlux_neg
The 1-σ negative error on the observed 0.3—10 keV flux from an automated power-law spectral fit to an automatically-extracted spectrum of the source. This is taken from the band0Rate_neg field multiplied by the FittedPowECFO field, so does not include uncertainties in the spectral modelling.
FittedPowUnabsFlux
The unabsorbed 0.3—10 keV flux (in erg cm-2 s-1), from an automated power-law spectral fit to an automatically-extracted spectrum of the source.
FittedPowUnabsFlux_pos
The 1-σ positive error on the unabsorbed 0.3—10 keV flux from an automated power-law spectral fit to an automatically-extracted spectrum of the source. This is taken from the band0Rate_pos field multiplied by the FittedPowECFU field, so does not include uncertainties in the spectral modelling.
FittedPowUnabsFlux_neg
The 1-σ negative error on the unabsorbed 0.3—10 keV flux from an automated power-law spectral fit to an automatically-extracted spectrum of the source. This is taken from the band0Rate_neg field multiplied by the FittedPowECFU field, so does not include uncertainties in the spectral modelling.
FittedPowNH
The absorption column (in cm-2) of the spectrum of the source from an automated power-law spectral fit to an automatically-extracted spectrum of the source.
FittedPowNH_pos
The 1-σ positive error absorption column of the spectrum of the source from an automated power-law spectral fit to an automatically-extracted spectrum of the source.
FittedPowNH_neg
The 1-σ negative error absorption column of the spectrum of the source from an automated power-law spectral fit to an automatically-extracted spectrum of the source.
FittedPowGamma
The power-law photon index of the spectrum of the source from an automated power-law spectral fit to an automatically-extracted spectrum of the source.
FittedPowGamma_pos
The 1-σ positive error on the power-law photon index of the spectrum of the source from an automated power-law spectral fit to an automatically-extracted spectrum of the source.
FittedPowGamma_neg
The 1-σ negative error on the power-law photon index of the spectrum of the source from an automated power-law spectral fit to an automatically-extracted spectrum of the source.
FittedPowChi
The Churazov-weighted χ2 value of the best fitting power-law spectral model.
FittedPowDOF
The number of degrees of freedom in the power-law spectral fit.
FittedPowRedChi
The Churazov-weighted χν2 value of the best fitting power-law spectral model.
FittedAPECECFO
The counts-to-observed-flux (0.3—10 keV) conversion factor (in erg cm-2 ct-1), derived from the hardness ratios of the source, from an automated APEC spectral fit to an automatically-extracted spectrum of the source.
FittedAPECECFU
The counts-to-unabsorbed-flux (0.3—10 keV) conversion factor (in erg cm-2 ct-1), derived from the hardness ratios of the source, from an automated APEC spectral fit to an automatically-extracted spectrum of the source.
FittedAPECFlux
The observed 0.3—10 keV flux (in erg cm-2 s-1), derived from the hardness ratios of the source, from an automated APEC spectral fit to an automatically-extracted spectrum of the source.
FittedAPECFlux_pos
The 1-σ positive error on the observed 0.3—10 keV flux derived from the hardness ratios of the source, from an automated APEC spectral fit to an automatically-extracted spectrum of the source. This is taken from the band0Rate_pos field multiplied by the FittedAPECECFO field, so does not include uncertainties in the spectral modelling.
FittedAPECFlux_neg
The 1-σ negative error on the observed 0.3—10 keV flux derived from the hardness ratios of the source, from an automated APEC spectral fit to an automatically-extracted spectrum of the source. This is taken from the band0Rate_neg field multiplied by the FittedAPECECFO field, so does not include uncertainties in the spectral modelling.
FittedAPECUnabsFlux
The unabsorbed 0.3—10 keV flux (in erg cm-2 s-1), derived from the hardness ratios of the source, from an automated APEC spectral fit to an automatically-extracted spectrum of the source.
FittedAPECUnabsFlux_pos
The 1-σ positive error on the unabsorbed 0.3—10 keV flux derived from the hardness ratios of the source, from an automated APEC spectral fit to an automatically-extracted spectrum of the source. This is taken from the band0Rate_pos field multiplied by the FittedAPECECFU field, so does not include uncertainties in the spectral modelling.
FittedAPECUnabsFlux_neg
The 1-σ negative error on the unabsorbed 0.3—10 keV flux derived from the hardness ratios of the source, from an automated APEC spectral fit to an automatically-extracted spectrum of the source. This is taken from the band0Rate_neg field multiplied by the FittedAPECECFU field, so does not include uncertainties in the spectral modelling.
FittedAPECNH
The absorption column (in cm-2) of the spectrum of the source derived from the hardness ratios of the source, from an automated APEC spectral fit to an automatically-extracted spectrum of the source.
FittedAPECNH_pos
The 1-σ positive error absorption column of the spectrum of the source derived from the hardness ratios of the source, from an automated APEC spectral fit to an automatically-extracted spectrum of the source.
FittedAPECNH_neg
The 1-σ negative error absorption column of the spectrum of the source derived from the hardness ratios of the source, from an automated APEC spectral fit to an automatically-extracted spectrum of the source.
FittedAPECkT
The APEC plasma temperature (in keV) of the spectrum of the source derived from the hardness ratios of the source, from an automated APEC spectral fit to an automatically-extracted spectrum of the source.
FittedAPECkT_pos
The 1-σ positive error on the APEC plasma temperature of the spectrum of the source derived from the hardness ratios of the source, from an automated APEC spectral fit to an automatically-extracted spectrum of the source.
FittedAPECkT_neg
The 1-σ negative error on the APEC plasma temperature of the spectrum of the source derived from the hardness ratios of the source, from an automated APEC spectral fit to an automatically-extracted spectrum of the source.
FittedAPECChi
The Churazov-weighted χ2 value of the best fitting APEC spectral model.
FittedAPECDOF
The number of degrees of freedom in the APEC spectral fit.
FittedAPECRedChi
The Churazov-weighted χν2 value of the best fitting APEC spectral model.

[Hide spectral/flux columns | Back to Sources table | Back to top | 1SXPS index]


Cross-correlation information

Numxcorr
The number of sources in the external catalogues against which we performed cross-correlation, which are within 3-σ of the location of this source. Where available, the uncertainty in the external catalogue source position was added in quadrature with the 1SXPS uncertainty to perform this match.
Numxcorr_slim
The number of sources in the external catalogues against which we performed cross-correlation excluding 2MASS and USNO-B1, which are within 3-σ of the location of this source. Where available, the uncertainty in the external catalogue source position was added in quadrature with the 1SXPS uncertainty to perform this match.
isROSHRI
Whether the object does (1) or does not (0) match an object in the Rosat HRI catalogue.
isROSPSPC
Whether the object does (1) or does not (0) match an object in the Rosat PSPC catalogue.
is3XMM
Whether the object does (1) or does not (0) match an object in the 3XMM DR4 catalogue.
isXMMSL1
Whether the object does (1) or does not (0) match an object in the XMMSL1 XMM-Newton slew survey catalogue.
isSwiftFT
Whether the object does (1) or does not (0) match an object in the Swift-FT catalogue.
is1SWXRT
Whether the object does (1) or does not (0) match an object in the 1SWXRT catalogue.
isXRTGRB
Whether the object does (1) or does not (0) match a catalogued XRT position of a Gamma Ray Burst.
isSDSSQSO
Whether the object does (1) or does not (0) match an object in the SDSS QSO DR5 catalogue.
is2MASS
Whether the object does (1) or does not (0) match a 2MASS source.
isUSNOB1
Whether the object does (1) or does not (0) match a USNO-B1 source.
isSIMBAD
Whether the object does (1) or does not (0) match a SIMBAD object.
xcorrIDs
The identifiers of the external catalogue sources which are within 3-σ of the 1SXPS source, as a semi-colon delimited list of object (catalogue) strings.

[Hide cross-correlation columns | Back to Sources table | Back to top | 1SXPS index]


Detections Table

The Detections table contains details of the specific detections that comprise the catalogue. Each source in the Sources table has at least one entry in this detections table; most sources have multiple entries as they were detected in more than one band or dataset. The information in the detections table relates to the specific detection, not to the unique source as a whole. The fields in this table, and their definitions are given below.

DetID
The unique identifier of this detection.
obsID
The unique identifier of the dataset in which the detection occurred. If this number is less than 8000 it is the number of the stacked image, otherwise it is a Swift obsid.
Band
The band in which this detection occurred, as an integer:
  • 0: Total band = 0.3—10 keV
  • 1: Soft band = 0.3—1 keV
  • 2: Medium band = 1—2 keV
  • 3: Hard band = 2—10 keV
DetFlag
The detection flag assigned for this specific detection. This is a numerical value, normally 0 (=Good), 1 (=Reasonable) or 2 (=Poor) For sources which lie inside a region which was identified in the manual screening stage as containing artefacts the flag values are 8, 9 and 10 for the three categories. Those in a region manually marked as containing diffuse emission have flag values of 16,17 and 18. In the case where the flag has a value >2 the Good, Reasonable or Poor definitions indicate the strength of the detection, however the source is highly likely nonetheless to be spurious.
img_x
The sky x position of the source in the specific dataset and energy band shown. For single observations, the nominal pointing direction corresponds to sky coordinates (500.5,500.5). For stacked images, (500.5,500.5) corresponds to the position of the field given in the Datasets table, but due to the nature of stacked image, this gives no information about where on the detector the source location was.
img_y
The sky y position of the source in the specific dataset and energy band shown. For single observations, the nominal pointing direction corresponds to sky coordinates (500.5,500.5). For stacked images, (500.5,500.5) corresponds to the position of the field given in the Datasets table, but due to the nature of stacked image, this gives no information about where on the detector the source location was.
OffAxis
The mean off-axis angle (in arc minutes) of the source in this specific dataset and energy band. This is calculated only from the snapshot during which source is inside the field of view. A value of -1 indicates that the source centre is never in the field of view (i.e. it was detected and localised via the PSF wings).
RA
The Right Ascension (J2000) of the source as determined from this specific dataset and energy band, using the astrometry from the on-board star trackers.
RA_pos/RA_neg
These 2 columns give the 1-σ statistical error on the source RA, determined from the PSF fit. For a small number of sources, the fit code was unable to determine an error in which case this field is empty.
Decl
The declination (J2000) of the source as determined from this specific dataset and energy band, using the astrometry from the on-board star trackers.
Dec_pos/Dec_neg
These 2 columns give the 1-σ statistical error on the source declination, determined from the PSF fit. For a small number of sources, the fit code was unable to determine an error in which case this field is empty.
Err90
The 90% confidence radial position error, including systematic error, using the astrometry from the on-board star trackers. This is derived from the RA and Decl errors above and has been converted to 90% confidence using Rayleigh statistics, with the the 3.5′′ astrometric systematic error from the star trackers added in quadrature. For the sources where one of the individual RA/Dec pos/neg errors was unavailable, the statistical radial 90% confidence error was set to be 14.6′′/√C (where C is the number of events used in the PSF fit) and the systematic error was combined with this.
RA_corr
The Right Ascension (J2000) of the source, as determined from this specific dataset and energy band, with the astrometry derived by correlating the X-ray sources detected in this image with the 2MASS catalogue.
Decl_corr
The declination (J2000) of the source, as determined from this specific dataset and energy band, with the astrometry derived by correlating the X-ray sources detected in this image with the 2MASS catalogue.
Err90_corr
The 90% confidence radial position error, derived as for The Err90 field above, but where the systematic error is taken from the X-ray/2MASS rectification process and not the on-board star trackers.
l,b
The Galactic co-ordinates of the source, in decimal degrees.
Counts
The total number of events (not background subtracted or exposure corrected) at the location of the source. The size and shape of the extraction region is a function of the source brightness and may vary between datasets and energy bands.
BGCts
The total number of counts in the background map at the location of the source. The size and shape of the extraction region is the same as for the Counts detected field.
FieldExposure
The on-axis exposure time, in seconds, of the dataset in which this detection occurred.
CF
The count-rate correction factor (κ in equation 9 of Evans et al. 2013) which corrects the count rate for vignetting, bad columns, pile up and the finite radius over which counts were extracted.
Rate
The on-axis equivalent mean count-rate for the source in this specific observation and energy band.
Rate_pos/neg
The 1-σ uncertainty in the count-rate. For sources with fewer than 30 detected events after background subtraction, this is calculated using the Bayesian approach of Kraft, Burrows & Nousek (1991), other Poisson statistics are employed.
ExposureFraction
The mean exposure time in the source extraction region as a fraction of the on-axis exposure time in the image.
Cstat
The C statistic value from the PSF fit to the source.
Cstat_nosrc
The C-statistic value calculated for a model with no source present.
LogLikelihood
The log likelihood of the difference between Cstat and Cstat_nosrc for 2 degrees of freedom being coincidence.
SNR
The signal-to-noise ratio of the source during the sliding cell detection phase, when this source was detected.
Celldet_width
The full width (in pixels, 1 pixel=2.357′′) of the cell in which the source was detected.
PSF_radius
The radius (in pixels) of the region used to perform the source PSF fit and likelihood test.
PSF
The PSF profile used to determine the source position, likelihood and count rate.
ol_warn
If a catalogued optical source bright enough to cause optical loading at the level of ≥10-3 ct s-1 pix-1 lies within 30′′ of the position of this detection, this field records how many magnitudes brighter than the level at which this optical loading occurs that source is catalogued as being.
FieldFlag
The flag assigned to the dataset of this detection. This can be either Good (=0) or Flagged (=1 or 2). The latter indicates that there are artefacts (flag=1) and/or extended emission (flag=2) in the field which may affect the flux levels of the point sources detected.
NNDist
The distance in arc seconds to the nearest source also detected in this dataset and energy band. If no other sources are detected this is empty.
OKNNDist
The distance in arc seconds to the nearest source flagged as Good or Reasonable also detected in this dataset and energy band. If no such sources are detected this is empty.
Num_snapshots
The number of snapshots in this dataset in which the source lies within the field of view.
ImageBG
The mean background (in ct s-1 pix-1) of the image in which this detection occurred.
MergeRadius
The radius (in pixels, 1 pix=2.357′′) around this detection of the source within which detections are assumed to be aliases of the source, and are thus discarded.
SourceID
The 1SXPS source of which this is a detection.

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Datasets Table

The Datasets table contains information about individual datasets — observations and stacked images — which make up the 1SXPS catalogue.

ID
The unique identifier of the dataset. If this number is less than 8000 it is the number of the stacked image, otherwise it is a Swift obsid.
RA
The Right Ascension (J2000.0) of the image centre in degrees.
Decl
The Right Ascension (J2000.0) of the image centre in degrees.
l,b
The Galactic coordinates of the image centre in degrees.
IsStacked
Whether this dataset is (1) or is not (0) a stacked image.
Exposure
The on-axis exposure time of the dataset, in seconds.
FieldBG_band0
The mean background value in the total (0.3—10 keV) band in ct s-1 pix-1. This is measured from the background map before the detected sources have been added to it.
Field BG_band1
The mean background value in the soft (0.3—1 keV) band in ct s-1 pix-1. This is measured from the background map before the detected sources have been added to it.
Field BG_band2
The mean background value in the medium (1—2 keV) band in ct s-1 pix-1. This is measured from the background map before the detected sources have been added to it.
Field BG_band3
The mean background value in the hard (2—10 keV) band in ct s-1 pix-1. This is measured from the background map before the detected sources have been added to it.
Numsrc_band0
The number of sources detected in the total (0.3—10 keV) band image of this dataset.
Numsrc_band1
The number of sources detected in the soft (0.3—1 keV) band image of this dataset.
Numsrc_band2
The number of sources detected in the medium (1—2 keV) band image of this dataset.
Numsrc_band3
The number of sources detected in the hard (1—10 keV) band image of this dataset.
NumOK_band0
The number of Good and Reasonable sources detected in the total (0.3—10 keV) band image of this dataset.
NumOK_band1
The number of Good and Reasonable sources detected in the soft (0.3—1 keV) band image of this dataset.
NumOK_band2
The number of Good and Reasonable sources detected in the medium (1—2 keV) band image of this dataset.
NumOK_band3
The number of Good and Reasonable sources detected in the hard (1—10 keV) band image of this dataset.
MedianNNDist_band0
The median distance between sources detected in the total (0.3—10 keV) band image of this dataset, in arc seconds.
MedianNNDist_band1
The median distance between sources detected in the soft (0.3—1 keV) band image of this dataset, in arc seconds.
MedianNNDist_band2
The median distance between sources detected in the medium (1—2 keV) band image of this dataset, in arc seconds.
MedianNNDist_band3
The median distance between sources detected in the hard (2—10 keV) band image of this dataset, in arc seconds.
Date_start
The UT date at time at which the observation began. For stacked images this is the time of the first observation within the stacked image.
Date_stop
The UT date at time at which the observation began. For stacked images this is the time of the first observation within the stacked image.
FieldFlag
The flag assigned to the field by manual inspection. This can be either Good (=0) or Flagged (=1 or 2). The latter indicates that there are artefacts (flag=1) and/or extended emission (flag=2) in the field which may affect the flux levels of the point sources detected.
NumSnapshots
The number of snapshots in the dataset.
AstromErr
If the astrometry of this image could be determined by matching the XRT sources with the 2MASS catalogue, this gives the 90% confidence radial error associated with that astrometry.
Stacked image
For observations this gives the ID of the stacked image to which the observation contributes (if any). For stacked images, this gives the ID of any other stacked images which overlap this dataset.

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Cross Correlations Table

The Cross correlations table contains details of the cross correlation between the 1SXPS sources and other catalogues.

1SXPS_ID
The name of the source in the 1SXPS catalogue.
ExtCat_ID
The name of the matched source in the external catalogue.
Catalogue
The name of the catalogue in which the match occurs.
Distance
The distance, in arc seconds, between the 1SXPS source and the external catalogue source.
RA
The Right Ascension (J2000), in decimal degrees, of the source in the external catalogue.
Decl
The declination (J2000), in decimal degrees, of the source in the external catalogue.
Err90
The 90% confidence radial error in the external catalogue position (if available). Where necessary, this has been converted from a 1-σ error using Rayleigh statistics, and has had any relevant systematic error added.

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