UNDER CONSTRUCTION:
The ``Black Holes In Binaries'' Research Program at UT

This site will be devoted to describing the research effort on black holes at UT, led by "Rob" Robinson and Bill Welsh. Patrick Young (now at U. Arizona), Cyndi Froning (now at STScI), and Divas Sanwal (now at Penn State) were also key members of our team.
This site is under construction.

Right now we are currently obtaining and analysing photometry of Aql X-1, J0422+32, and GS2000+25 to measure the "ellipsoidal variations" in the light curves. From the ellipsoidal variations, we can estimate the inclination of the binary. Coupled with the mass function (derived from spectroscopy), we can get accutate masses for the central objects. This work is difficult because the targets are faint and in very crowded fields.
In addition, we have been awarded top-priority time on the HET to study J0422, and we have HET TOO observatinos of the new X-ray transient J1859+226 during outburst.

We are also studying the very peculiar X-ray transient CI Cam. We have obtained high resolution spectra of CI Cam over the course of many months, and are in the process of completing our analysis of the outburst spectra. We also have been awarded HST time, with the observations expected in the Spring of 2000.

We have also been investigating in detail the technique of using the rotational velocity of the companion star ("Vrot sin i") to get the mass ratio and inclination of the binary.

And if stellar black holes are not big enough for you, we are also studying supermassive black holes in AGN.

For HET use:
FINDING CHARTS FOR THE HET:
J0422 big finder chart. J0422 small finder chart.
Gl 412A finder chart.

Markarian 335 finder chart.

Back to Welsh's research page

This page was last updated on 1999 Oct 28