Eric Deutsch
Department of Astronomy, University of Washington

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Current Research

I'm working on a host of different projects at the moment. Here, I've just compiled a short list of some of the things I've been working on. Some of the projects which I've finished aren't listed here, but you can find details on those at my page of publications.

In December, 1998 I completed my Ph.D. thesis, entitled ``The Optical Counterparts of the Luminous X-ray Binary Stars in Globular Clusters''. In this work, I presented candidates for three additional optical counterparts to low-mass X-ray binaries (LMXBs) in globular clusters, thereby doubling the number of optical counterpart candidates. A homogeneous set of HST photometric measurements for all of the counterparts identified thus far is presented, and their optical properties are compared with those of field low-mass X-ray binaries. In addition, new and archival spectra and imaging data are analyzed to intercompare the UV/optical spectral energy distributions (SEDs) of GC LMXBs. A set of simple model SEDs is introduced and compared with the observations to infer accretion rates, disk diameters, and other properties of these systems. This work strengthens previous inferences that many if not most of the globular cluster LMXBs are ultra-compact systems with orbital periods less than 1 hr. Much of this work has been published in papers I've already published, and now I'm putting together the remaining points into another paper.

Although not part of my thesis, I am working on detecting the infrared counterpart to the Rapid Burster, a totally unique object in the globular cluster Liller 1. I used the APO 3.5m telescope and the GRIM II infrared imager to take time-resolved imaging observations of the cluster during the Rapid Bursters most recent X-ray outburst. Prelimary results were presented at the most recent AAS meeting. I'm now refining the data analysis and preparing a journal article on this work.

One of the brightest exotic Galactic X-ray sources (GX 17+2) is still without an optical counterpart. The star NP Ser has been considered: although it's nearly in the correct position, it appears to be a completely normal star. As pointed out in Deutsch et al. (1995) there is a small positional discrepancy which indeed precludes NP Ser, but no better candiate was suggested in the WFPC2 images we examined. Now, I'm examining some recent NICMOS images of the field armed with better astrometry based on the USNO-A2.0 catalog. We've now submitted this work to the ApJ.

Gamma-ray bursts are all the rage these days. I've been working on optical follow-on observations of these events as member of the APO GRB team. We've written a couple papers and short observation reports. With its remote observing capability, the APO 3.5m is well suited to afterglow observations and we intend to make full use of this capability.

I've been working on a project which involves searching several globular clusters for eclipsing binaries. Basically, I spend many nights obtaining images of these globular clusters, looking for apparently-single stars which periodically get fainter when the two stars eclipse each other. I've selected four globular clusters which have a range in central density and metallicity in order to explore the variation in the fraction of binary stars with these parameters. I'm taking these observations at the Cerro Tololo Interamerican Observatory in Chile with the 2048x2048 pixel Cassegrain focus CCD camera on the 36 inch telescope. My first run was 12 nights in June 1996, and the second run was 13 nights in November 1996. I think I have all the data I need; now I just need to reduce this 20 GB volume of data!

In 1994 I wrote a journal article presenting proper motions, coordinates, and finding charts for a dozen or so stars belonging to a relatively new class, the dwarf carbon star. I've been collecting UBVRI photometry of some of these objects and hope to finish doing so this spring on the 30 inch telescope at the Manastash Ridge Observatory, and soon we will be writing a paper examining magnitudes and colors for all of these stars as well as presenting another dwarf carbon star.

The University of Washington is a one-third partner in a 3.5 meter telescope at the Apache Point Observatory (APO). This telescope only began operating a few years ago, and so in addition to some of the science projects described above, I been involved in some engineering work. The general information page provides links to all the APO stuff I'm doing. Some of the highlights:

• I've written the controlling software which runs a neat little infrared (10 micron) all-sky camera up at APO. My computer here at UW tells the camera to scan and then fetches the images from APO to UW over the internet, processes them into nice GIF images, and puts them on the WWW so that remote observers can monitor sky conditions from anywhere.
• Along similar lines, I've written software which fetches weather data which is logged at APO and generates snazzy graphs of the current weather conditions for remote observers to monitor.
• Due to the current state of the guider on the 3.5m, it is extremely useful to select good guide stars before observations begin. To aid in this, I've constructed a system by which 3.5m observers can request my computer to generate a Guider Acquisition Chart for any part of the sky.
• In addition to creating software to generate the charts, I did a good bit of work characterizing the guider system to make it available to the general observer. In doing so, I put together a Web page of details about the guider.

There are a few other scattered projects, but those are the main ones. I hope I'll make good progress on these and other projects in the coming months.