Monitor proportional counter

An Uhuru class Ar-CO2 gas filled proportional counter sealed with a 1.5 mil beryllium window and sensitive to X-rays in the energy bandwidth from 1.5 to 22 keV is presented. This device is coaligned with the X-ray telescope aboard the Einstein Observatory and takes data as a normal part of the Observatory operations

The Development and Scientific Impact of the Chandra X-Ray Observatory

I review the operational capabilities of the Chandra X-ray Observatory, including some of the spectacular results obtained by the general observer community. A natural theme of this talk is that Chandra is revealing outflows of great quantities of energy that were not previously observable. I highlight the Chandra studies of powerful X-ray jets. This subject is only possible due to the sub-arcsecond resolution of the X-ray telescope.Comment: 8 pages, 4 figures. Talk given at the International Workshop on Astronomy and Relativistic Astrophysics (IWARA2003), Olinda, Brasil, October 2003. To appear in the International Journal of Modern Physics

The AXAF technology program: The optical flats tests

The results of a technology program aimed at determining the limits of surface polishing for reflecting X-ray telescopes is presented. This program is part of the major task of developing the Advanced X-ray Astrophysical Facility (AXAF). By studying the optical properties of state-of-the-art polished flat surfaces, conclusions were drawn as to the potential capability of AXAF. Surface microtopography of the flats as well as their figure are studied by X-ray, visual, and mechanical techniques. These techniques and their results are described. The employed polishing techniques are more than adequate for the specifications of the AXAF mirrors

High time resolution observation of the transient event of 5 March 1979

The detection of an intense gamma ray burst with the monitor proportional counter on the HEAO 2 spacecraft is discussed with particular emphasis on the measurement of the time of onset of the event. Based on the mean observed counting rate in the burst and assuming a sharp rise, the uncertainty in the burst onset is found to be + or - 220 microseconds. The time of occurrence was 57124.826908 + or - 0.000220 s UT on March 5, 1979, and the location of the HEAO 2 satellite at this time was latitude 22.15 deg, longitude -27.60 deg at an altitude of 525.0 km

QED vacuum fluctuations and induced electric dipole moment of the neutron

Quantum fluctuations in the QED vacuum generate non-linear effects, such as peculiar induced electromagnetic fields. In particular, we show here that an electrically neutral particle, possessing a magnetic dipole moment, develops an induced electric dipole-type moment with unusual angular dependence, when immersed in a quasistatic, constant external electric field. The calculation of this effect is done in the framework of the Euler-Heisenberg effective QED Lagrangian, corresponding to the weak field asymptotic expansion of the effective action to one-loop order. It is argued that the neutron might be a good candidate to probe this signal of non-linearity in QED.Comment: A misprint has been corrected, and three new references have been adde