Table · dataset · 2026
M 81 Chandra X-Ray Point Source Catalog
Listed in IVOA Registry (Virtual Observatory)
This table contains the source table from an analysis of 15 Chandra ACIS observations of the nearby spiral galaxy M81 taken over the course of six weeks in 2005 May-July.
Description
Each observation reaches a sensitivity of ~10<sup>37</sup> erg s<sup>-1</sup>. With these observations and one previous deeper Chandra observation (the properties of which are described in Table 1 and Section 2 of the reference paper), the authors have compiled a master source list of 265 point sources, extracted and fitted their spectra, and differentiated basic populations of sources through their colors.
They also carried out variability analyses of individual point sources and of X-ray luminosity functions (XLFs) in multiple regions of M 81 on timescales of days, months, and years. They find that, despite measuring significant variability in a considerable fraction of sources, snapshot observations provide a consistent determination of the XLF of M81. They also fit the XLFs for multiple regions of M81 and, using common parametrization, compare these luminosity functions to those of two other spiral galaxies, M31 and the Milky Way.
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This table contains the 265 point sources at or above the 99.9% probability level of being real according to AE's PROB_NO_SOURCE statistic (the "master" source list), and 11 additional "borderline" sources which have 99.0-99.9% probability of being real according to AE's PROB_NO_SOURCE statistic, for a total of 276 sources whose properties were described in Tables 3 and 4 of the reference paper.
The 265 "master" sources have source numbers from 1 to 265 while the 11 "borderline" sources have source numbers beginning with 'B', e.g., they have source numbers 'B1' to 'B11'. Note that only coordinates are listed for 3 sources in the master source list (source numbers 234, 241 and 262) and 2 sources in the borderline source list (B8 and B9) because they were only in the field of view (on chip) of one observation (ObsID 735).
Six additional sources near the center of M81 which were found using maximum likelihood image reconstruction are not included in either the master or borderline source lists contained herein but their positions are listed in table 2 of the reference paper. This table was created by the HEASARC in August 2011 based on electronic versions of Tables 3 and 4 from the reference paper which were obtained from the ApJ web site.
Some of the values for the name parameter in the HEASARC's implementation of this table were corrected in April 2018. This is a service provided by NASA HEASARC .
Links
Where it is published
- Reference page heasarc.gsfc.nasa.gov/W3Browse/all/m81cxo2.html ↗
landing page · from IVOA Registry
Catalogue records · 2
- VOResource record dc.g-vo.org/oai.xml?verb=GetRecord&metadataPrefix=ivo_vor&identifier=ivo%3… ↗
metadata API · from IVOA Registry
- Registry record (GAVO) dc.g-vo.org/I/nasa.heasarc/m81cxo2 ↗
catalogue entry · from IVOA Registry
Topics
- Stated by source
- X-Ray
- From keywords
- Astronomy & Astrophysics
Provenance · 1 source records, 9 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| IVOA Registry (Virtual Observatory) | ivo://nasa.heasarc/m81cxo2 | 14 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| access_level | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[field].local:field:astronomy | mapping · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[modality].ivoa_waveband:x-ray | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[modality].local:modality:image | enrichment · IVOA Registry | keyword-concept-rules@1.0.0 | title+description (75%) |
| concepts[modality].local:modality:tabular | enrichment · IVOA Registry | keyword-concept-rules@1.0.0 | title+description (65%) |
| description | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_description |
| publication_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| title | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_title |
| updated_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 |