An x-ray investigation of the NGC346 field in the SMC (2): the field population

Y Naze, Joanna Hartwell, Ian Stevens, J Manfroid, S Marchenko, MF Corcoran, AFJ Moffat, G Skalkowski

Research output: Contribution to journalArticle

20 Citations (Scopus)


We present results from a Chandra observation of the NGC 346 cluster, which is the ionizing source of N66, the most luminous H II region and the largest star formation region in the SMC. In the first part of this investigation, we have analyzed the X-ray properties of the cluster itself and the remarkable star HD 5980, but the field contains additional objects of interest. In total, 75 X-ray point sources were detected in the Chandra observation: this is 5 times the number of sources detected by previous X-ray surveys. We investigate here their characteristics in detail. Because of high foreground absorption, the sources possess rather high hardness ratios. Their cumulative luminosity function appears generally steeper than that for the rest of the SMC at higher luminosities. Their absorption columns suggest that most of the sources belong to NGC 346. Using Digitized Sky Survey data and new UBVRI imaging with the ESO 2.2 m telescope, we also discovered possible counterparts for 32 of these X-ray sources and estimated a B spectral type for a large number of these counterparts. This tends to suggest that most of the X-ray sources in the field are in fact X-ray binaries. Finally, some objects show X-ray and/or optical variability, with a need for further monitoring.
Original languageEnglish
Pages (from-to)983-995
Number of pages13
JournalThe Astrophysical Journal
Issue number2
Publication statusPublished - 1 Apr 2003


  • Magellanic Clouds
  • HII regions
  • X-rays : individual (NGC 346)
  • galaxies : star clusters


Dive into the research topics of 'An x-ray investigation of the NGC346 field in the SMC (2): the field population'. Together they form a unique fingerprint.

Cite this