The authors of this catalog carried out a study of the X-ray properties of the supernova remnant (SNR) population in M 33 with XMM-Newton, comprising deep observations of eight fields in M 33 covering all of the area within the D₂₅ contours, and with a typical luminosity of 7.1 x 10³⁴ erg/s (0.2-2.0keV). With their deep observations and large field of view they have detected 105 SNRs at the 3-sigma level, of which 54 SNRs are newly detected in X-rays, and three are newly discovered SNRs. Combining XMM-Newton data with deep Chandra survey data allowed detailed spectral fitting of 15 SNRs, for which they have measured temperatures, ionization time-scales and individual abundances. This large sample of SNRs allowed the authors to construct an X-ray luminosity function, and compare its shape to luminosity functions from host galaxies of differing metallicities and star formation rates to look for environmental effects on SNR properties. They concluded that while metallicity may play a role in SNR population characteristics, differing star formation histories on short time-scales, and small-scale environmental effects appear to cause more significant differences between X-ray luminosity distributions. In addition, they analyze the X-ray detectability of SNRs, and find that in M 33 SNRs with higher [SII]/H-alpha ratios, as well as those with smaller galactocentric distances, are more detectable in X-rays. This catalog utilized data from a deep survey of M 33 using an 8 field XMM-Newton mosaic that extends out to the D25 isophote. The point source catalog from this survey was published by W15 (Williams+2015, J/ApJS/218/9). In addition to the catalog of W15, the authors utilized high-resolution observations from the Chandra ACIS Survey of M 33 (ChASeM33, Tullmann+2011, J/ApJS/193/31) for the purposes of obtaining X-ray spectral fits. This table was ingested by the HEASARC in October 2019 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/472/308">CDS Catalog J/MNRAS/472/308</a> files table2.dat and table3.dat. This is a service provided by NASA HEASARC .