A complete database for the Einstein imaging proportional counter

A complete database for the Einstein Imaging Proportional Counter (IPC) was completed. The original data that makes up the archive is described as well as the structure of the database, the Op-Ed analysis system, the technical advances achieved relative to the analysis of (IPC) data, the data products produced, and some uses to which the database has been put by scientists outside Columbia University over the past year

Analysis and interpretation of diffuse x-ray emission using data from the Einstein satellite

An ambitious program to create a powerful and accessible archive of the HEAO-2 Imaging Proportional Counter (IPC) database was outlined. The scientific utility of that database for studies of diffuse x ray emissions was explored. Technical and scientific accomplishments are reviewed. Three papers were presented which have major new scientific findings relevant to the global structure of the interstellar medium and the origin of the cosmic x ray background. An all-sky map of diffuse x ray emission was constructed

Far infrared observations of crab-like supernova remnants

Using the Infrared Astronomy Satellite (IRAS) data, an investigation was begun of the far infrared properties of Crab-like supernova remnants and other synchrotron nebulae. Both the co-added scanning data and, where available, pointed observations were examined. To date infrared emission was found from two Crab-like remnants: G24.7+0.6 in which the infrared source near the center of the object was shown to be a compact HII region with EM greater than or approximately 10 to the 7th pc/cm(6); and G0.9+0.1 where a marginal detection of a 25 micron source coincident with the remnant core was used to set limits on the energetics of this synchrotron nebula. Further work, in progress under a second year of this program, should yield additional information concerning the distribution of initial pulsar spin periods and the evolution of synchrotron nebulae

The x ray population in globular clusters and three crab-like SNR in the large Magellanic cloud

This document is to serve as the requisite Final Technical Report on grant NAG5-1557 which was awarded under the NASA ROSAT Guest Investigator Program to Columbia University. In response to the NASA Research Anouncement describing the first round of Guest Investigations to be carried out under the U.S.-German ROSAT Program (AO-1), the PI submitted several proposals, three of which were accepted in part: (1) the x-ray population of globular clusters; (2) three crab-like SNR in the Large Magellanic Cloud; and (3) x rays from nearby radio pulsars. The status of these three programs as of 31 May 1993, the termination date of the grant, is reported

Constraining Omega_0 With The Angular-Size Redshift Relation Of Double-Lobed Quasars In The FIRST Survey

In previous attempts to measure Omega_0 from the angular size-redshift (theta-z) relation of double-lobed radio sources, the observed data have been consistent with a static Euclidean universe, rather than with Friedmann models, and past authors have disagreed as to what effects are responsible. These results may be due to a variety of selection effects, different sample definitions, and inconsistencies in the analysis undermining the results. Using the VLA FIRST survey, we investigate the theta-z relation for a new sample of 103 double-lobed quasars, carefully addressing the various potential problems which, we believe, have compromised past work. Before focusing on cosmological constraints, we investigate the possible impact of correlations among the intrinsic properties of these sources over the entire assumed range of allowed cosmological parameter values. For all cases, we find only mild apparent size evolution which is found to arise mainly from a power-size correlation coupled with a power-redshift correlation; intrinsic size evolution is consistent with zero. We also find that in all cases, an evolution-free subsample can be defined, whose theta-z relation should arise mainly from cosmological effects. Contrary to past work, we find that the observed theta-z relation for our sample is more consistent with standard Friedmann models than with a static Euclidean universe. In particular, we find that a flat, matter-dominated universe, a flat universe with a cosmological constant, and an open universe all provide comparably good fits to the data, with the latter two models both yielding Omega_0 \approx 0.35 with 1-sigma ranges including values between \sim 0.25 and 1.0; the evolution-free subsamples yield values of Omega_0 near unity, though with even greater error ranges.Comment: 48 pages (AASTex) including tables and 6 Postscript figures, to appear in ApJ, acknowledgements correcte