DEEP Chandra MONITORING OBSERVATIONS OF NGC 4278: CATALOG OF SOURCE PROPERTIES

We present the properties of the discrete X-ray sources detected in our monitoring program of the globularcluster (GC) rich elliptical galaxy, NGC 4278, observed with Chandra ACIS-S in six separate pointings, result-ing in a co-added exposure of 458-ks. From this deep observation, 236 sources have been detected within theregion overlapped by all observations, 180 of which lie within the D25 ellipse of the galaxy. These 236 sourcesrange in LX from 3.5×1036 erg s−1 (with 3σ upper limit ≤1×1037 erg s−1) to ∼ 2 ×1040erg s−1, including thecentral nuclear source which has been classified as a LINER. From optical data, 39 X-ray sources have beendetermined to be coincident with a globular cluster, these sources tend to have high X-ray luminosity, withten of these sources exhibiting LX> 1× 1038erg s−1. From X-ray source photometry, it has been determinedthat the majority of the 236 point sources that have well constrained colors, have values that are consistentwith typical LMXB spectra, with 29 of these sources expected to be background objects from the logN − logSrelation. There are 103 sources in this population that exhibit long-term variability, indicating that they areaccreting compact objects. 3 of these sources have been identified as transient candidates, with a further 3 pos-sible transients. Spectral variations have also been identified in the majority of the source population, where adiverse range of variability has been identified, indicating that there are many different source classes locatedwithin this galaxy. Subject headings: galaxies: individual (NGC 4278) — X-rays: galaxies — X-ray: binaries