DETERMINING THE ABSOLUTE ASTROMETRIC ERROR IN CHANDRA SOURCE CATALOG POSITIONS

Astrometric Control of the Inertiality of the Hipparcos Catalog

Treatment of star catalog biases in asteroid astrometric observations

In this paper, we discuss the detection of systematic biases in star positions of the USNO A1.0, A2.0, and B1.0 catalogs, as deduced from the residuals of numbered asteroid observations. We present a technique for the removal of these biases, and validate this technique by illustrating the resulting improvements in numbered asteroid residuals, and by establishing that debiased orbits predict om...

The Extended Chandra Deep Field-South Survey: X-ray Point-Source Catalog

The Extended Chandra Deep Field-South (ECDFS) survey consists of 4 Chandra ACIS-I pointings and covers ≈ 1100 square arcminutes (≈ 0.3 deg) centered on the original CDF-S field to a depth of approximately 228 ks. This is the largest Chandra survey ever conducted at such depth, and only one XMMNewton survey reaches a lower flux limit in the hard 2.0–8.0 keV band. We detect 651 unique sources — 5...

Extended Source Effects in Astrometric Gravitational Microlensing

Extended source size effects have been detected in photometric monitoring of gravitational microlensing events. We study similar effects in the centroid motion of an extended source lensed by a point mass. We show that the centroid motion of a source with uniform surface brightness can be obtained analytically. For a source with circularly symmetric limb-darkening profile, the centroid motion c...

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...