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FORNAXXMM - Fornax Dwarf Galaxy XMM-Newton X-Ray Point Source Catalog

HEASARC
Archive

Overview

This table contains some of the results of a deep archive XMM-Newton observation of the Fornax spheroidal galaxy that the authors analyzed with the aim of fully characterizing the X-ray source population (in most of the cases likely to be background active galactic nuclei) detected towards the target. A cross-correlation with the available databases allowed them to find a source that may be associated with a variable star belonging to the galaxy. The authors also searched for X-ray sources in the vicinity of the Fornax globular clusters GC 3 and GC 4 and found two sources probably associated with the respective clusters. The deep X-ray observation was also suitable for the search for the intermediate-mass black hole (of mass ~ 104 solar masses) expected to be hosted in the center of the galaxy. In the case of Fornax, this search is extremely difficult since the galaxy centroid of gravity is poorly constrained because of the large asymmetry observed in the optical surface brightness. Since the authors cannot firmly establish the existence of an X-ray counterpart of the putative black hole, they put constraints only on the accretion parameters. In particular, they found that the corresponding upper limit on the accretion efficiency, with respect to the Eddington luminosity, is as low as a few 10-5.

Catalog Bibcode

2013A&A...550A..18N

References

An XMM-Newton search for X-ray sources in the Fornax dwarf galaxy.
    Nucita A.A., Manni L., De Paolis F., Vetrugno D., Ingrosso G.
   <Astron. Astrophys. Vol. 550, A18. (2013)>
   =2013A&A...550A..18N

Provenance

This table was created by the HEASARC in February 2013 based on an electronic version of Table 1 from the reference paper which was obtained from the A&A web site.

Parameters

Source_Number
A unique internal sequence number for each X-ray source in order of increasing X-ray flux.

Name
The X-ray source designation ('[NMD2013] nnn') using the NMD0213 prefix (for Nucita, Manni, De Paolis 2013) and the source number. This was created by the HEASARC in the position-based IAU style recommended by the Dictionary of Nomenclature of Celestial Objects

Source_Flags
This parameter can contain flags indicating source characteristics, as follows: 'P' (sources with an asterisk in the printed table) means that the X-ray source is possibly associated (within 1 sigma) with a counterpart found in the Position and Proper Motions eXtended Catalog (PPMX, see Roeser et al. 2008, A&A, 488, 401), thus implying it may be a possible foreground source; 'V' flags source number 61: when correlating the X-ray sources with the available catalogs, the authors found that this source is possibly associated, within 2.0", with an object (J023941.4-343340) belonging to a catalog of variable stars (Bersier & Wood 2002, AJ, 123, 840) [See the text of the reference paper for details]; 'M' flags source number 107: this X-ray source also correlates (within 1.0") with a source in the 2MASX Catalog (Skrutskie et al. 2006, AJ, 131, 1163) and is possibly associated with a background AGN (QJ0240-3437, see also Mendez et al. (2011, AJ, 143, 93) where this quasar has been considered as a reference object for measuring the proper motion of sources belonging to the Fornax dSph); as a consequence, source 107 may have been erroneously reported in the PPMX catalog (source labeled as 024019.0-343719).

Detect_Flag
This parameter contains a a label indicating which EPIC camera (or set of cameras) detected the X-ray source, i.e.,

  Value    Detector(s)

  A         pn only,
  B         pn and MOS 1,
  C         pn and MOS 2,
  D         pn, MOS 1, and MOS 2,
  E         MOS 1 and MOS 2,
  F         MOS 1,
  G         MOS 2.
  

RA
The Right Ascension of the X-ray source in the selected equinox. This was given in J2000.0 equatorial coordinates to a precision of 0.1 seconds of time in the original table.

Dec
The Declination of the X-ray source in the selected equinox. This was given in J2000.0 equatorial coordinates to a precision of 0.1 arcseconds 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 of the X-ray source, in arcseconds.

Hardness_Ratio_1
The hardness ratio HR1 of the X-ray source, defined as HR1 = (H-M)/(S+M+H), of the X-ray source, where S, M, and H correspond to the count rates in the 0.3-1 keV, 1-4 keV and 4-10 keV energy bands.

Hardness_Ratio_1_Error
The uncertainty in the hardness ratio HR1.

Hardness_Ratio_2
The hardness ratio HR2 of the X-ray source, defined as HR2 = (M-S)/(S+M+H), of the X-ray source, where S, M, and H correspond to the count rates in the 0.3-1 keV, 1-4 keV and 4-10 keV energy bands.

Hardness_Ratio_2_Error
The uncertainty in the hardness ratio HR2.

Flux
The absorbed 0.2-12 keV flux of the X-ray source, in erg s-1 cm-2. The X-ray flux in a given band was defined as Fi = Bi / ECFi, where Bi is the count rate in the i band and ECFi is an energy conversion factor which has been calculated using the most recent calibration matrices for the MOS 1, MOS 2, and pn. The authors used the ECFs obtained assuming a power-law model with photon index Gamma = 1.7 and a Galactic foreground absorption of NH = 3.0 x 1020 cm-2 (Watson et al. 2009, A&A, 493, 339).

Flux_Error
The uncertainty in the absorbed 0.2-12 keV flux of the X-ray source, in erg s-1 cm-2

XMM_2MASS_Offset
The offset of a nearby 2MASS/2MASX source from the X-ray source position, in arcseconds. The authors associated with the coordinates of each of the identified X-ray sources an error resulting from the quadrature sum of the XMM-Newton positional accuracy (~ 2" at a 2-sigma confidence level) and the statistical error as determined by the edetect_chain tool. Similarly, the error associated with the infrared counterpart position was derived from the 2MASS catalog. When an X-ray source is found to be within 1 sigma of a 2MASS counterpart, a value for the offset is given.

XMM_USNOB1_Offset
The offset of a nearby USNO-B1 source from the X-ray source position, in arcseconds. The authors associated with the coordinates of each of the identified X-ray sources an error resulting from the quadrature sum of the XMM-Newton positional accuracy (~ 2" at a 2-sigma confidence level) and the statistical error as determined by the edetect_chain tool. Similarly, the error associated with the optical counterpart position was derived from the USNO-B1 catalog. When an X-ray source is found to be within 1 sigma of a USNO-B1 counterpart, a value for the offset is given.


Contact Person

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

Page Author: Browse Software Development Team
Last Modified: 25-Feb-2013