Deep Chandra Monitoring Observations of NGC 3379: Catalog of Source Properties

Nicola Brassington, G. Fabbiano, D.-W. Kim, A. Zezas, S. Zepf, A. Kundu, L. Angelini, R. L. Davies, J. Gallagher, V. Kalogera, T. Fragos, A.R. King, S. Pellegrini, G. Trinchieri

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    We present the properties of the discrete X-ray sources detected in our monitoring program of the `typical' elliptical galaxy, NGC 3379, observed with Chandra ACIS-S in five separate pointings, resulting in a co-added exposure of 324 ks. From this deep observation, 132 sources have been detected within the region overlapped by all observations, 98 of which lie within the D25 ellipse of the galaxy. These 132 sources range in LX from 6×1035 erg s-1 (with 3 σ upper limit <=4×1036 erg s-1) to ~2×1039 erg s-1, including one source with LX>1×1039 erg s-1, which has been classified as a ULX. From optical data, 10 X-ray sources have been determined to be coincident with a globular cluster, these sources tend to have high X-ray luminosity, with three of these sources exhibiting LX>1×1038 erg s-1. From X-ray source photometry, it has been determined that the majority of the 132 sources that have well constrained colors, have values that are consistent with typical LMXB spectra. In addition to this, a subpopulation of 10 sources has been found to exhibit very hard spectra and it is expected that most of these sources are absorbed background AGN. There are 64 sources in this population that exhibit long-term variability, indicating that they are accreting compact objects. Five of these sources have been identified as transient candidates, with a further 3 possible transients. Spectral variations have also been identified in the majority of the source population, where a diverse range of variability has been identified, indicating that there are many different source classes located within this galaxy.
    Original languageEnglish
    Pages (from-to)142-165
    Number of pages24
    JournalAstrophysical Journal, Supplement Series
    Issue number1
    Publication statusPublished - 1 Nov 2008


    • Galaxies: Individual: NGC Number: NGC 3379, X-Rays: Binaries, X-Rays: Galaxies


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