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M33CHASE - M 33 Chandra ACIS Survey (ChASeM33) Final Source Catalog

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Overview

This table contains the final source catalog of the Chandra ACIS Survey of M33 (ChASeM33). With a total exposure time of 1.4 Ms, ChASeM33 covers ~70% of the D25 isophote (radial extent ~ 4.0 kpc) of M33 and provides the deepest, most complete, and detailed look at a spiral galaxy in X-rays. The source catalog includes 662 sources, reaches a limiting unabsorbed luminosity of ~2.4 x 1034 erg s-1 in the 0.35-8.0 keV energy band, and contains source positions, source net counts, fluxes and significances in several energy bands, and information on source variability. The analysis challenges posed by ChASeM33 and the techniques adopted to address these challenges are discussed. To constrain the nature of the detected X-ray source, hardness ratios were constructed and spectra were fit for 254 sources, follow-up Multiple Mirror Telescope (MMT) spectra of 116 sources were acquired, and cross-correlations with previous X-ray catalogs and other multi-wavelength data were generated. Based on this effort, 183 of the 662 ChASeM33 sources could be identified. Finally, in the reference paper, the luminosity function (LF) for the detected point sources as well as the one for the X-ray binaries (XRBs) in M33 were presented. The LFs in the soft band (0.5-2.0 keV) and the hard band (2.0-8.0 keV) have a limiting luminosity at the 90% completeness limit of 4.0 x 1034 erg s-1 and 1.6 x 1035 erg s-1 (for an assumed distance D to M33 of 817 kpc), respectively, which is significantly lower than what was reported by previous XRB population studies in galaxies more distant than M33. The resulting distribution is consistent with a dominant population of high-mass XRBs as would be expected for M33.

The list of all the Chandra ACIS observations that were used in the construction of this source catalog is given in table 2 of the 2011 reference paper.

X-ray source properties, such as counts, dns values, and photon fluxes were computed in the following energy bands:

Band   Energy Range (keV)

1      0.5 - 8.0
2      0.5 - 2.0
3      2.0 - 8.0
4      0.35- 8.0
5      0.35- 1.1
6      1.1 - 2.6
7      2.6 - 8.0
8      0.35- 2.0

Catalog Bibcode

2011ApJS..193...31T

References

The Chandra ACIS Survey of M33 (ChASeM33): The Final Source Catalog
   Tullmann, R., Gaetz, T.J., Plucinsky, P.P., Kuntz, K.D., Williams, B.F.,
   Pietsch, W., Haberl, F., Long, K.S., Blair, W.P., Sasaki, M.,
   Winkler, P.F., Challis, P., Pannuti, T.G., Edgar, R.J., Helfand, D.J.,
   Hughes, J. P., Kirshner, R.P., Mazeh, T., Shporer, A.
  <Astrophys. J., Suppl. Ser., 193, 31 (2011)>
  =2011ApJS..193...31T

Chandra ACIS Survey of M33 (ChASeM33): A First Look
   Plucinsky, P.P., Williams, B., Long, K.S., Gaetz, T.J., Sasaki, M.,
   Pietsch, W., Tullmann, R., Smith, R.K., Blair, W.P., Helfand, D.,
   Hughes, J.P., Winkler, P.F., de Avillez, M., Bianchi, L., Breitschwerdt, D.,
   Edgar, R.J., Ghavamian, P., Grindlay, J., Haberl, F., Kirshner, R.,
   Kuntz, K., Mazeh, T., Pannuti, T.G., Shporer, A., Thilker, D.A.
  <Astrophys. J., Suppl. Ser., 174, 366-378 (2008)>
  =2008ApJS..174..366P

Provenance

This table was created by the HEASARC in April 2011 based on electronic versions of Tables 3, 4, 5, 6, 7 and 9 from the 2011 reference paper which were obrained from the ApJS web site.

Parameters

Source_Number
This parameter is a unique source number identifying ChASeM33 sources. Sources are listed in order of increasing J2000 right ascension. Notice that, in general, these numbers do not correspond to the source numbers used in the 2008 paper.

Name
The designation for the X-ray source, using the 'ChASeM33FC' prefix (Chandra ACIS Survey of M 33, Final Catalog), followed by the source number value. This was created by the HEASARC based on the 'ChASeM33' prefix used in the 2008 paper for sources in the 'First Look' catalog.

Alt_Name
An alternative X-ray source designation for the X-ray source using the '[TGP2011]' prefix (for Tullmann, Gaetz, Plucinsky 2011), and the J2000.0 equatorial positional coordinates, e.g., '[TGP2011] J013224.55+303322.3'. This designation, based on CDS Dictionary of Nomenclature of Celestial Objects standard practises, was created by the HEASARC.

RA
The Right Ascension of the X-ray source in the selected equinox. This was given in J2000.0 equatorial coordinates in the original table.

Dec
The Declination of the X-ray source in the selected equinox. This was given in J2000.0 equatorial coordinates in the original table.

LII
The Galactic Longitude of the X-ray source.

BII
The Galactic Latitude of the X-ray source.

Error_Radius
The positional uncertainty in the X-ray source position, expressed as the radius in arcseconds of a simple circle centered on the position. The rationale behind the calculation of this parameter is discussed in the last paragraph of Section 2.3.1 of the 2011 reference paper.

Num_Obs
The number of individual observations of the given source.

Exposure
The total exposure of the source in all observations, in seconds (s).

Tot_Exposure_Map
The sum of the mean exposure map values in the source region for all observations, in units of s cm2.

Source_Radius
The average radius of the source extraction region, in sky pixels, where 1 sky pixel = 0.492 arcseconds.

Bck_Radius
The average radius of the background extraction region, in sky pixels, where 1 sky pixel = 0.492 arcseconds.

Off_Axis
The average off-axis angle of the X-ray source, in arcminutes.

B1_PNS_Limit
This limit parameter is set to '<' if the corresponding parameter value is an upper limit rather than an actual value.

B1_PNS
The Poisson probability of the X-ray source 'not being a source', pns, i.e., the Poisson probability that all of the counts in the source extraction region are actually from the background, in the 0.5-8.0 keV energy band. pns values less than 1.0E-10 have been replaced by the upper limit of 1.0E-10. All such cases are highly significant detections.

B2_PNS_Limit
This limit parameter is set to '<' if the corresponding parameter value is an upper limit rather than an actual value.

B2_PNS
The Poisson probability of the X-ray source 'not being a source', pns, i.e., the Poisson probability that all of the counts in the source extraction region are actually from the background, in the 0.5-2.0 keV energy band. pns values less than 1.0E-10 have been replaced by the upper limit of 1.0E-10. All such cases are highly significant detections.

B3_PNS_Limit
This limit parameter is set to '<' if the corresponding parameter value is an upper limit rather than an actual value.

B3_PNS
The Poisson probability of the X-ray source 'not being a source', pns, i.e., the Poisson probability that all of the counts in the source extraction region are actually from the background, in the 2.0-8.0 keV energy band.pns values less than 1.0E-10 have been replaced by the upper limit of 1.0E-10. All such cases are highly significant detections.

B4_PNS_Limit
This limit parameter is set to '<' if the corresponding parameter value is an upper limit rather than an actual value.

B4_PNS
The Poisson probability of the X-ray source 'not being a source', pns, i.e., the Poisson probability that all of the counts in the source extraction region are actually from the background, in the 0.35-8.0 keV energy band.pns values less than 1.0E-10 have been replaced by the upper limit of 1.0E-10. All such cases are highly significant detections.

B5_PNS_Limit
This limit parameter is set to '<' if the corresponding parameter value is an upper limit rather than an actual value.

B5_PNS
The Poisson probability of the X-ray source 'not being a source', pns, i.e., the Poisson probability that all of the counts in the source extraction region are actually from the background, in the 0.35-1.1 keV energy band.pns values less than 1.0E-10 have been replaced by the upper limit of 1.0E-10. All such cases are highly significant detections.

B6_PNS_Limit
This limit parameter is set to '<' if the corresponding parameter value is an upper limit rather than an actual value.

B6_PNS
The Poisson probability of the X-ray source 'not being a source', pns, i.e., the Poisson probability that all of the counts in the source extraction region are actually from the background, in the 1.1-2.6 keV energy band.pns values less than 1.0E-10 have been replaced by the upper limit of 1.0E-10. All such cases are highly significant d etections.

B7_PNS_Limit
This limit parameter is set to '<' if the corresponding parameter value is an upper limit rather than an actual value.

B7_PNS
The Poisson probability of the X-ray source 'not being a source', pns, i.e., the Poisson probability that all of the counts in the source extraction region are actually from the background, in the 2.6-8.0 keV energy band.pns values less than 1.0E-10 have been replaced by the upper limit of 1.0E-10. All such cases are highly significant detections.

B8_PNS_Limit
This limit parameter is set to '<' if the corresponding parameter value is an upper limit rather than an actual value.

B8_PNS
The Poisson probability of the X-ray source 'not being a source', pns, i.e., the Poisson probability that all of the counts in the source extraction region are actually from the background, in the 0.35-2.0 keV energy band.pns values less than 1.0E-10 have been replaced by the upper limit of 1.0E-10. All such cases are highly significant detections.

B1_Counts
The total net source counts in the 0.5-8.0 keV energy band.

B1_Counts_Pos_Err
The upper 90% confidence level error in the associated parameter.

B1_Counts_Neg_Err
The lower 90% confidence level error in the associated parameter.

B2_Counts
The total net source counts in the 0.5-2.0 keV energy band.

B2_Counts_Pos_Err
The upper 90% confidence level error in the associated parameter.

B2_Counts_Neg_Err
The lower 90% confidence level error in the associated parameter.

B3_Counts
The total net source counts in the 2.0-8.0 keV energy band.

B3_Counts_Pos_Err
The upper 90% confidence level error in the associated parameter.

B3_Counts_Neg_Err
The lower 90% confidence level error in the associated parameter.

B4_Counts
The total net source counts in the 0.35-8.0 keV energy band.

B4_Counts_Pos_Err
The upper 90% confidence level error in the associated parameter.

B4_Counts_Neg_Err
The lower 90% confidence level error in the associated parameter.

B5_Counts
The total net source counts in the 0.35-1.1 keV energy band.

B5_Counts_Pos_Err
The upper 90% confidence level error in the associated parameter.

B5_Counts_Neg_Err
The lower 90% confidence level error in the associated parameter.

B6_Counts
The total net source counts in the 1.1-2.6 keV energy band.

B6_Counts_Pos_Err
The upper 90% confidence level error in the associated parameter.

B6_Counts_Neg_Err
The lower 90% confidence level error in the associated parameter.

B7_Counts
The total net source counts in the 2.6-8.0 keV energy band.

B7_Counts_Pos_Err
The upper 90% confidence level error in the associated parameter.

B7_Counts_Neg_Err
The lower 90% confidence level error in the associated parameter.

B8_Counts
The total net source counts in the 0.35-2.0 keV energy band.

B8_Counts_Pos_Err
The upper 90% confidence level error in the associated parameter.

B8_Counts_Neg_Err
The lower 90% confidence level error in the associated parameter.

B1_Photon_Flux
The merged photon flux of the X-ray source, in units of photons cm-2 s-1, in the 0.5-8.0 keV energy band.

B2_Photon_Flux
The merged photon flux of the X-ray source, in units of photons cm-2 s-1, in the 0.5-2.0 keV energy band.

B3_Photon_Flux
The merged photon flux of the X-ray source, in units of photons cm-2 s-1, in the 2.0-8.0 keV energy band.

B4_Photon_Flux
The merged photon flux of the X-ray source, in units of photons cm-2 s-1, in the 0.35-8.0 keV energy band.

B5_Photon_Flux
The merged photon flux of the X-ray source, in units of photons cm-2 s-1, in the 0.35-1.1 keV energy band.

B6_Photon_Flux
The merged photon flux of the X-ray source, in units of photons cm-2 s-1, in the 1.1-2.6 keV energy band.

B7_Photon_Flux
The merged photon flux of the X-ray source, in units of photons cm-2 s-1, in the 2.6-8.0 keV energy band.

B8_Photon_Flux
The merged photon flux of the X-ray source, in units of photons cm-2 s-1, in the 0.35-2.0 keV energy band.

FLC_Source_Number
The ChASeM33 First Look Catalog (Plucinsky et al. 2008) source number corresponding to this Chandra source, if any.

PMH04_Source_Number
THe PMH04 (Pietsch et al.2004, A&A, 426, 11) source number of the (XMM-Newton) source corresponding to this Chandra source, if any.

MPH06_Source_Number
The MPH06 (Misanovic et al. 2006, A&A, 448, 1247) source number of the (XMM-Newton) source corresponding to this Chandra source, if any.

G05_Source_Number
The G05 (Grimm et al. 2005, ApJS, 161, 271) source number of the (Chandra) source corresponding to this catalog source, if any.

Extent_Flag
This flag parameter contains coded information on the X-ray source extent, as follows:

      0 = not extended
      1 = extended
      2 = possibly extended
  

LT_Var_Index
The 5-sigma variability index, eta, a parameter which is sensitive to long-term variability. Sources with variability indices eta >= 5.0 are highly likely to have shown long-term variability and have been indicated as such by having the parameter lt_var_flag set to 'b'.

LT_Var_Flag
This flag parameter is set to 'b' to indicate sources which are highly likely to have exhibited long-term variability.

Ks_Prob_Constant_Limit
This limit parameter is set to '<' if the corresponding parameter value is an upper limit rather than an actual value.

Ks_Prob_Constant
The Kolmogorov-Smirnov (K-S) probability of the source being constant within a single observation, i.e., of short-term variability. Sources with K-S probabilities of <= 5.7E-07 are highly likely to have shown short-term variability and have been indicated as such by having the parameter ks_prob_constant_flag set to 'b'.

Ks_Prob_Constant_Flag
This flag parameter is set to 'b' to indicate sources which are highly likely to have exhibited short-term variability.

Max_To_Min_Flux
The variability factor of the X-ray source expressed as the ratio of the maximum to minimum X-ray fluxes.

Max_To_Min_Flux_Error
The 1-sigma uncertainty in the ratio of the maximum to minimum X-ray fluxes.

H_Alpha_SB
The H-alpha surface brightness at the X-ray source position, in erg s-1 cm-2 arcsec-2, measured from the Local Group Galaxies Survey (LGGS, Massey et al. 2006, AJ, 131, 2478) data and extracted from a circular region with a radius of 2 arcseconds. Blank entries indicate the source either did not lie inside the central LGGS field or it is coincident with a foreground star.Any values of < 5.0E-17 erg s-1 cm-2 arcsec-2 are probably consistent with zero.

Type_And_Id_Comments
Source classification and aliases using the USNO-B1.0 Catalog (Monet et al. 2003, AJ, 125, 984) and the 2MASS catalog (Cutri et al. 2003, http://irsa.ipac.caltech.edu/applications/Gator/ ). The authors discern the following types of sources: (a) foreground stars (FS), (b) stellar sources in M33, (c) galaxies, (d) QSOs/AGN, (e) non-stellar sources, (f) SNRs (labeled "L10-XXX"), (g) XRBs, and (h) transient sources (labeled "XRT"). For the transients and the SNRs they use data from the ChASeM33 transient search (Williams et al. 2008, ApJ, 680, 1120) as well as from the ChASeM33 SNR Catalog (Long et al. 2010, ApJS, 187, 495). The classification of classes (a)-(e) is based on MMT follow-up spectroscopy and multi-wavelength data (see Section 3.2 of the 2011 reference paper).

Other_Comments
Additional special comment(s) about the source.

Best_Fit_Model
The best-fit spectral model type for the X-ray source, either a power-law (pow) or a vapec model, depending on which one has the lower reduced chi-squared value.

NH
The column density, nH, in H atoms cm-2, internal to M33. The Galactic column density towards M33 was fixed at a value of 0.06 x 1022 H atoms cm-2 (Dickey and Lockman 1990, ARAA, 28, 215).

NH_Pos_Err
The upper 90%-confidence level error in nH.

NH_Neg_Err
The lower 90%-confidence level error in nH.

Spectral_Index
The spectral index, Gamma,of the best-fit power-law model of the X-ray source spectrum.

Spectral_Index_Pos_Err
The upper 90%-confidence level error in Gamma.

Spectral_Index_Neg_Err
The lower 90%-confidence level error in Gamma.

APEC_kT
The plasma temperature, kT, in keV, of the best-fit vapec model of the X-ray source spectrum.

APEC_kT_Pos_Err
The upper 90%-confidence level error in kT, in keV.

APEC_kT_Neg_Err
The lower 90%-confidence level error in kT, in keV.

Fit_Norm
The normalization constant of the best-fit model of the X-ray source spectrum, in units of photons keV-1 cm-2 s-1 at 1 keV for the power-law model and of cm-5 for the vapec model.

Fit_Norm_Pos_Err
The upper 90%-confidence level error in the normalization constant of the best-fit model, in units of photons keV-1 cm-2 s-1 at 1 keV for the power-law model and of cm-5 for the vapec model.

Fit_Norm_Neg_Err
The lower 90%-confidence level error in the normalization constant of the best-fit model, in units of photons keV-1 cm-2 s-1 at 1 keV for the power-law model and of cm-5 for the vapec model.

Fit_DoF
The number of degrees of freedom (dof) of the best-fit spectral model of the X-ray source.

Reduced_Chi_Squared
The reduced Chi2 of the best-fit spectral model of the X-ray source.

SB_Lx
The absorption-corrected 0.35-2 keV energy band luminosity of the X-ray source, in erg s-1, assuming a distance to M33 of 817 kpc (Freedman et al. 2001, ApJ, 553, 47).

SB_Lx_Pos_Err
The upper 90%-confidence level error in the absorption-corrected 0.35-2 keV energy band luminosity of the X-ray source, in erg s-1.

SB_Lx_Neg_Err
The lower 90%-confidence level error in the absorption-corrected 0.35-2 keV energy band luminosity of the X-ray source, in erg s-1

Lx
The absorption-corrected 0.35-8 keV energy band luminosity of the X-ray source, in erg s-1, assuming a distance to M33 of 817 kpc (Freedman et al. 2001, ApJ, 553, 47).

Lx_Pos_Err
The upper 90%-confidence level error in the absorption-corrected 0.35-8 keV energy band luminosity of the X-ray source, in erg s-1.

Lx_Neg_Err
The lower 90%-confidence level error in the absorption-corrected 0.35-8 keV energy band luminosity of the X-ray source, in erg s-1


Contact Person

Questions regarding the M33CHASE database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 5-Mar-2012