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IX/40  The XMM-Newton 2nd Incremental Source Catalogue (2XMMi)  (XMM-SSC, 2008)

The XMM-Newton 2nd Serendipitous Source Catalogue XMM-Newton Survey Science Centre Consortium <XMM-SSC, Leicester, UK (2008)> =2008yCat.9040....0X
ADC_Keywords: X-ray sources ; Surveys ; Mission_Name: XMM Description: The 2XMMi catalogue is the fourth publicly released XMM X-ray source catalogue produced by the XMM Survey Science Centre (SSC) consortium, following the 1XMM (Cat. IX/37, released in April 2003), 2XMMp (July 2006) and 2XMM (Cat. IX/39, August 2007) catalogues: 2XMMp was a preliminary version of 2XMM. 2XMMi is an incremental version of the 2XMM catalogue. The 2XMMi catalogue is about 17% larger than the 2XMM catalogue, which it supersedes, due to the 1-year longer baseline of observations included (it is about 8 times larger than the 1XMM catalogue). As such, it is the largest X-ray source catalogue ever produced, containing more than twice as many discrete sources as either the ROSAT survey or pointed catalogues. 2XMMi complements deeper Chandra and XMM-Newton small area surveys, probing a large sky area at the flux limit where the bulk of the objects that contribute to the X-ray background lie. The 2XMMi catalogue provides a rich resource for generating large, well-defined samples for specific studies, utilizing the fact that X-ray selection is a highly efficient (arguably the most efficient) way of selecting certain types of object, notably active galaxies (AGN), clusters of galaxies, interacting compact binaries and active stellar coronae. The large sky area covered by the serendipitous survey, or equivalently the large size of the catalogue, also means that 2XMMi is a superb resource for exploring the variety of the X-ray source population and identifying rare source types. The production of the 2XMMi catalogue has been undertaken by the XMM-Newton SSC consortium in fulfilment of one of its major responsibilities within the XMM-Newton project. The catalogue production process has been designed to exploit fully the capabilities of the XMM-Newton EPIC cameras and to ensure the integrity and quality of the resultant catalogue through rigorous screening of the data. The predecessor 2XMM catalogue was made from a subset of public observations emerging from a re-processing (in 2006/7) of all XMM observations made prior to that point. The creation of the incremental 2XMMi catalogue has been driven by the desire to make public the additional data from that re-processing that were proprietary at the time of the 2XMM release but which subsequently became public before 01 May 2008. These have been augmented with a further 90 observations that have been processed more recently as part of the routine, day-to-day XMM data processing performed by the SSC, which were also public at 01 May 2008. Together, these amount to 626 additional observations (18%) with respect to 2XMM. With these new data, the sky area covered grows by 19% while the number of detections increases by 17% and the number of unique sources by 15%. A key factor in the decision to make the 2XMMi catalogue is the fact that, effectively, all the new data have been processed with the same science analysis software (SAS), pipeline and calibration as used in the aforementioned re-processing. As such, the products from 2XMM and from the new observations form a set of uniformly processed data. With software and calibration changes now being propagated into the SSC processing pipeline, it was deemed timely to make public the largest available uniform catalogue. The catalogue in its FITS version file ( has 246897 entries made of 297 columns; a 'slim' version gathering the 39 most relevant columns for the 191870 unique sources detected, is available as an ascii table or a FITS binary table. In both versions, the columns are fully described in the XMM-Newton User Guide available from: The original names of these columns are included in the "Byte-by-byte Description" below (uppercase names within parentheses) Details about the construction of the catalogue can be found from the XMM-Newton Survey Science Centre ( File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file xmm2is.dat 434 221012 The 2XMMi catalog, "slim" version 2880 137495 Full XMM-Newton 2nd Serendipitous Source Catalogue (300 columns), FITS format
See also: : 2XMM Home Page B/xmm : XMM-Newton Observation Log (XMM-Newton Science Operation Center, 2002) : XMM-Newton Survey Science Centre, University of Leicester : XSA Centre at ESA's XMM-Newton SOC : XCAT-DB at SSC institute, Strasbourg : LEDAS, at the SSC institute, University of Leicester J/A+A/493/339 : XMM-Newton serendipitous Survey V. (Watson+, 2009) Byte-by-byte Description of file: xmm2is.dat
Bytes Format Units Label Explanations
1- 6 I6 --- Source [1,221170] (SRCID) Unique source index 8- 12 A5 --- --- [2XMMi ] 14- 29 A16 --- 2XMMi (IAUNAME) Unique source name (7) 31- 38 F8.4 deg RAdeg (SC_RA) Mean source right ascension (ICRS) 40- 47 F8.4 deg DEdeg (SC_DEC) Mean source declination (ICRS) 49- 52 F4.1 arcsec ePos (SC_POSERR) Mean error on position 54- 65 E12.6 mW/m2 Flux1 (SCEP1_FLUX) Mean flux in 0.2-0.5keV band 67- 75 E9.3 mW/m2 e_Flux1 (SCEP1FLUXERR) Mean error on Flux1 77- 88 E12.6 mW/m2 Flux2 (SCEP2_FLUX) Mean flux in 0.5-1.0keV band 90- 98 E9.3 mW/m2 e_Flux2 (SCEP2FLUXERR) Mean error on Flux2 100-111 E12.6 mW/m2 Flux3 (SCEP3_FLUX) Mean flux in 1.0-2.0keV band 113-121 E9.3 mW/m2 e_Flux3 (SCEP3FLUXERR) Mean error on Flux3 123-134 E12.6 mW/m2 Flux4 (SCEP4_FLUX) Mean flux in 2.0-4.5keV band 136-144 E9.3 mW/m2 e_Flux4 (SCEP4FLUXERR) Mean error on Flux4 146-157 E12.6 mW/m2 Flux5 (SCEP5_FLUX) Mean flux in 4.5-12keV band 159-167 E9.3 mW/m2 e_Flux5 (SCEP5FLUXERR) Mean error on Flux5 169-180 E12.6 mW/m2 Flux (SCEP8_FLUX) Mean flux in 0.2-12keV band 182-190 E9.3 mW/m2 e_Flux (SCEP8FLUXERR) Mean error on Flux 192-203 E12.6 mW/m2 Flux14 ? (SCEP9_FLUX) Mean flux in 0.5-4.5keV band 205-213 E9.3 mW/m2 e_Flux14 ? (SCEP9FLUXERR) Mean error on Flux14 215-221 F7.4 --- HR1 ? (SC_HR1) Hardness ratio of bands 1 and 2 (1) 223-229 F7.4 --- e_HR1 ? (SCHR1ERR) Mean error on HR1 231-237 F7.4 --- HR2 ? (SC_HR2) Hardness ratio of bands 2 and 3 (1) 239-245 F7.4 --- e_HR2 ? (SCHR2ERR) Mean error on HR2 247-253 F7.4 --- HR3 ? (SC_HR3) Hardness ratio of bands 3 and 4 (1) 255-261 F7.4 --- e_HR3 ? (SCHR3ERR) Mean error on HR3 263-269 F7.4 --- HR4 ? (SC_HR4) Hardness ratio of bands 4 and 5 (1) 271-277 F7.4 --- e_HR4 ? (SCHR4ERR) Mean error on HR4 279-287 E9.3 --- srcML (SC_DET_ML) Source detection likelihood (2) 289-297 E9.3 --- extML (SC_EXT_ML) Detection likelihood of the extended source (3) 299-303 F5.3 --- Cst [0,1]? (SC_CHI2PROB) Constant probability (4) 305 I1 --- V [0,1] (SCVARFLAG) Variability flag (V=1) 307 I1 --- S [0,4] (SC_SUM_FLAG) summary flag (5) 309 I1 --- Chg [1,3] (SC_CHFLAG1) Changes compared to 2XMM (7) 311-312 I2 --- Nd (N_DETECTIONS) Number of detections 314-317 A4 --- --- [1XMM] 319-334 A16 --- 1XMM (MATCH_1XMM) Name of matched 1XMM source (6) 336-339 F4.1 arcsec o1XMM [0,3]? (SEP_1XMM) Distance of 1XMM source 341-434 A94 --- uLEDAS (LEDAS_URL) URL for details at LEDAS
Note (1): The hardness ratio is defined as (F2-F1)/(F2+F1) if F2 is the flux in the harder band (the hardness ratio is therefore -1 for softest sources and +1 for hardest sources). The energy bands are (note they differ from catalog 1XMM): 1 = 0.2 - 0.5 keV (narrow band) 2 = 0.5 - 1.0 keV (narrow band) 3 = 1.0 - 2.0 keV (narrow band) 4 = 2.0 - 4.5 keV (narrow band) 5 = 4.5 - 12.0 keV (narrow band) 6 = 0.2 - 2.0 keV = soft broad band, no images made 7 = 2.0 - 12.0 keV = hard broad band, no images made 8 = 0.2 - 12.0 keV = total band 9 = 0.5 - 4.5 keV = XID band Note (2): defined as the maximum of the likelihoods of all detections of this source. Note (3): defined as the average of the extent likelihoods of all detections of this source. Note (4): χ2 probability that the unique source as detected by any of the observations is constant, that is, the minimum value of the EPIC probabilities in each detection. Note (5): The summary flag of the source is derived from the EPIC flag, and is assigned the following values: 0 = good: none of the EPIC flags was set. 1 = source parameters may be affected: at least one of the EPIC warning flags was set, but no possible-spurious detection flag is set. 2 = possibly spurious source: at least one of the possible-spurious detection flags was set but not the manual flag 3 = source located in a area where spurious detection may occur. 4 = source located in a area where spurious detection may occur and is possibly spurious. Note (6): within a radius of 3arcsec Note (7): the 'Chg' flag indicates whether a source is (1) a 2XMM source with unchanged averaged parameters, (2) a 2XMM source with changed averaged parameters, or (3) a new source. In the case (3), the source is named '2XMMi' followed by the contents of the 2XMM column (2nd column); the name is otherwise 2XMM followed by the contents of the 2XMM column.
Acknowledgements: It is a pleasure to thank Clive Page and Simon R. Rosen, who prepared the 'slim' version. History: * 03-Sep-2008: Original version * 19-Jan-2009: energy bands in Note (1) above corrected (thanks to Simon Richard Rosen)
(End) Francois Ochsenbein [CDS] 03-Sep-2008
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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