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NGC2903CXO - NGC 2903 Central Region Chandra X-Ray Point Source Catalog

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Overview

This table contains some of the results from a deep Chandra observation of the central regions of the late-type barred spiral galaxy NGC 2903. The Chandra data reveal soft (kTe ~ 0.2 - 0.5 keV) diffuse emission in the nuclear starburst region and extending ~ 2' (~ 5 kpc) to the north and west of the nucleus. Much of this soft hot gas is likely to be from local active star-forming regions; however, besides the nuclear region, the morphology of hot gas does not strongly correlate with the bar or other known sites of active star formation. The central ~ 650 pc radius starburst zone exhibits much higher surface brightness diffuse emission than the surrounding regions and a harder spectral component in addition to a soft component similar to the surrounding zones. The authors interpret the hard component as also being of thermal origin with kTe ~ 3.6 keV and to be directly associated with a wind fluid produced by supernovae and massive star winds similar to the hard diffuse emission seen in the starburst galaxy M82. The inferred terminal velocity for this hard component, ~ 1100 km/s, exceeds the local galaxy escape velocity suggesting a potential outflow into the halo and possibly escape from the galaxy gravitational potential. Morphologically, the softer extended emission from nearby regions does not display an obvious outflow geometry. However, the column density through which the X-rays are transmitted is lower in the zone to the west of the nucleus compared to that from the east and the surface brightness is relatively higher suggesting some of the soft hot gas originates from above the disk: viewed directly from the western zone but through the intervening disk of the host galaxy along sight lines from the eastern zone. There are several point-like sources embedded in the strong diffuse nuclear emission zone. Their X-ray spectra show them to likely be compact binaries. None of these detected point sources are coincident with the mass center of the galaxy and the authors place an upper limit on the luminosity from any point-like nuclear source o < 2 x 1038 erg/s in the 0.5 - 8.0keV band, which indicates that NGC 2903 lacks an active galactic nucleus. Heating from the nuclear starburst and a galactic wind may be responsible for preventing cold gas from accreting onto the galactic center.

NGC 2903, a nearby (8.9 Mpc, 1" = 43 pc) late-type barred SAB(rs)bc galaxy with strong circumnuclear star formation, was observed with Chandra using the ACIS-S instrument in imaging mode on 2010 March 7 (ObsID 11260). The source finding tool in lextrct (Tennant 2006, AJ, 132, 1372) was applied in the energy range of 0.5 - 8.0 keV in order to detect point sources inside the D25 isophote. A total of 92 point-like sources were detected with a signal-to-noise ratio (S/N) above 2.4 (see Tennant 2006) and with a minimum of 5 counts above the background uncertainty. This table contains this list of point-like sources.


Catalog Bibcode

2012ApJ...758..105Y

References

Hot diffuse emission in the nuclear starburst region of NGC 2903.
    Yukita M., Swartz D.A., Tennant A.F., Soria R., Irwin J.A.
   <Astrophys. J., 758, 105 (2012)>
   =2012ApJ...758..105Y

Provenance

This table was created by the HEASARC in September 2014 based on CDS Catalog J/ApJ/758/105 file table3.dat.

Parameters

Source_Number
A unique Chandra X-ray source number, in order of increasing J2000.0 Right Ascension.

Name
The Chandra X-ray source designation. This was created by the HEASARC in the style recommended by the CDS Dictionary of Nomenclature of Celestial Objects for 'unregistered' Chandra sources, using the prefix of 'CXOU' and the J2000.0 equatorial coordinates truncated to 0.1 seconds in RA and 1" in Dec.

RA
The Right Ascension of the Chandra 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. The listed source positions are refinements from the initial source detection estimates; refined positions were made by fitting circular Gaussian models to the spatial distribution of X-ray events in the vicinity of each source.

Dec
The Declination of the Chandra source in the selected equinox. This was given in J2000.0 equatorial coordinates to a precision of 0.1 arcseconds in the original table. The listed source positions are refinements from the initial source detection estimates; refined positions were made by fitting circular Gaussian models to the spatial distribution of X-ray events in the vicinity of each source.

LII
The Galactic Longitude of the Chandra source.

BII
The Galactic Latitude of the Chandra source.

Counts
The number of source counts (0.5 - 8.0 keV), corrected for the finite-aperture model point-spread function (PSF.

SNR
The signal-to-noise ratio of the Chandra source.

Lx
The estimated intrinsic source luminosity in the 0.5 - 8.0 keV energy band, in erg/s. The source luminosities were estimated from the average count rate during the observation using the Portable Interactive Multi-Mission Simulator (PIMMS) assuming an absorbed power-law spectral shape with spectral index Gamma = 1.95 and with a hydrogen column density equal to the Galactic column density along the line of sight of NGC 2903, nH = 2.9 x 1020 cm-2, and solar abundances.


Contact Person

Questions regarding the NGC2903CXO database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 8-Sep-2014