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2005 Annual Report

II. Research

A few of the research activities were sufficiently newsworthy to be Press Releases:

• "NASA Scientists Conduct Census of Nearby Hidden Black Holes",
  NASA/GSFC, ESA & UMBC releases by JCA member Volker Beckmann
• "INTEGRAL Catches a New Erupting Black Hole",
  NASA/GSFC, ESA & UMBC releases also by JCA member Volker Beckmann
• "XMM-Newton Spots the Greatest of Great Balls of Fire",
  ESA & UMBC releases by JCA-affiliates Alexis Finoguenov & Mark Henriksen,

The contributions of individual members are (briefly) summarized below .

David Band has been applying the methodology he developed to analyze the detectability of gamma-ray bursts to different missions such as the Gamma-ray Large Area Space Telescope (GLAST, launch: 2007 Fall) and EXIST (a proposed 'Black Hole Finder' mission for the 'Beyond Einstein' program). He is a member of the team designing the EXIST mission. He assisted Y. Kaneko in analyzing the spectral catalog she created for her doctoral thesis (U. Alabama, Huntsville). He continues to work with M. Stamatikos (currently at GSFC) on analyzing the neutrino upper limits from AMANDA (a neutrino detector at the South Pole).

Volker Beckmann contributed mainly to the AGN research at hard X-rays using the INTEGRAL and Swift observatories. In this respect he published the first INTEGRAL AGN catalog and the first hard X-ray luminosity function of AGN. He presented results from his research activities in an invited talk at the 207th AAS meeting in Washington D.C. in January, in another invited presentation at the Yale Center for Astronomy and Astrophysics in February. He gave further scientific presentations in March at the MPE in Munich, in June at the University College Dublin, in July at the 6th INTEGRAL workshop in Moscow. His work was also in the focus of two press releases (see above).

John Cannizzo began a major new project - the development of a code to utilize Glimm's Method for calculating relativistic hydrodynamics. This method consists of solving exact equations locally, and then propagating the solutions globally using a special-purpose random number generator. The initial results using a 1D code produced solutions to standard test problems that are generally much more precise than standard techniques - i.e., using the relativistic solver in the FLASH module. For certain problems, such as the deceleration of an ultrarelativistic flow against a barrier, the agreement with the exact solution is limited by machine precision only. Dr Cannizzo also continued on the development of the Hilbert-Huang transform (HHT) as a research tool in gravitational wave searches for LIGO and LISA. Advanced methods were incorporated into previously written code to handle downsampling, EEMD (Ensemble Empirical Mode Decomposition), and LPEF (linear predictor error filter). The HHT was applied to the SuperMassive Black Hole (SMBH) inspiral problems in the first LISA Mock Data Challenge. For Swift, Dr Cannizzo continued to work on a variety of fronts involving theoretical considerations, and data analysis. One new project was a collaborative effort with Joe Dolan and Padi Boyd to look at Swift data on SS433.

James Chiang is working with J. Carson (SLAC) on models of gamma-ray emission from blazars to constrain with forthcoming GLAST/LAT observations extragalactic background light and to probe the broad line regions of flat spectrum radio quasars. Chiang is working with Carson, S. Digel (SLAC) and P. Nolan (Stanford) on understanding the reference distributions in Poisson-limited cases for point source detection. These studies will be crucial for determining significance of weak point sources and upper limits for LAT data. With M. A. Nowak, A. Young (MIT), C. S. Reynolds (UMCP) and others, Chiang was awarded Chandra observations to study the Seyfert galaxy NGC 4258 to probe the inner disk, anomalous arms, and X-ray binary populations; and Chiang applied, with these same researchers, for Suzaku observations (results pending) of the Seyfert galaxy NGC 5548 to do broad band spectral energy distribution studies in order to understand the accretion flow in this object. Chiang is working with B. Dingus and S. Casanova (LANL) on reanalyzing CGRO/EGRET data using the LAT analysis software in order to study the Galactic center region and gamma-ray bursts. He is working with D. van Dyk (U.C. Irvine) and A. Connors (Eureka) on image reconstruction of gamma-ray data from EGRET and the LAT using their EMC2 algorithm and Markoff Random Fields to do scale-dependent smoothing and to assess the signficance of extended structures.

Jay Cummings research mainly involves the analysis of Swift/BAT observations of the prompt radiation of Gamma-ray Bursts (GRBs). He is regularly on call for immediate (real-time) analysis of burst activity. Notices of BAT triggers are automatically disseminated to the GRB investigator community via the Tracking and Data Relay Satellite System (TDRSS), and are followed up with a human-generatede GRB Coordinate Network (GCN) Circular within minutes to confirm a GRB, rather than a hard X-ray transient. Within a few hours, once the trigger data has reached the ground through the normal downlink, a second GCN is issued, elaborating on the nature of the source. Some sources are if sufficient interest to warrant a paper in a refereed journal in their own right. Others are included in comparative analysis of several bursts. Dr. Cummings provided analysis and figures of BAT spectra and lightcurves for several papers. As he is often the only native speaker among the coauthors, on many occasions he also took on the primary role of text editing.

Dave Davis has finished the analysis for Abell 222 and writing the ApJ paper for submission (with JCA-Affiliate Alexis Finoguenov) and preparing to present the results at the upcoming AAS meeting. Dr Davis was also awarded XMM observing time for observations of an elliptical galaxy (BGC4649) and have a successful ADP proposal (both of these with Mike Loewenstein as PI). He has also refereed at least one paper during the reporting period.

Along with with the work with Dr Dave Davis, and the work (and press release) with Dr Mark Henriksen reported above, JCA Affiliate Alexis Finoguenov led the work on a survey of HD properties of a large sample of groups of galaxies resulting in two publications.

JCA-affiliate Markos Georganopoulos focused his research on the X-ray emission mechanism of the large scale quasar jets that has been detected by Chandra. Currently, there are two different interpretations for this emission and no clear diagnostics to separate between the two. Since these two interpretations require jet of very different physical conditions the nature the X-ray emission mechanism has wide implications. Together with JCA-Affiliate Eric Perlman, and Drs. Kazanas & McEnery (NASA/GSFC), Dr. Georganopoulos devised a diagnostic test based on the anticipated GeV and TeV emission of the jet, and applied it to the archetypical quasar 3C 273. Together with Perlman and collaborators, Dr. Georganopoulos also continued observational studies of quasar jets in the X-rays. Dr. Georganopoulos supervised the UMBC undergraduate student Philip Graff during the summer. Mr. Graff presented the first results of his work, on variable GeV-TeV emission from compact sources, at the meeting of the High Energy Astrophysics Division of the American Astronomical Society in October, and is currently working on his Senior Thesis under the supervision of Dr. Georganopoulos. Finally, a further research highlight during this period was that the prediction that Georganopoulos, Perlman, & Kazanas made last year (2005 ApJ, 634, L33) that the base of the jet close to the super massive black hole at the center of M87 is the source of TeV emission was confirmed by HESS, a European TeV telescope in Namibia (Aharonian et al. 2006, Science, 314, 1424).

Masaharu Hirayama continued working on evaluating effectiveness of GLAST observing strategies for pulsar studies, including estimation of pulse detection sensitivity in a particular observation mode. It has been difficult to identify or numerically define scientific merits of a pointed observation of a particular pulsar over an all-sky scanning observation. The work continues.

James van Meter was on travel at the time the technical reports were due.

\ JCA-Affiliate Jane Turner was an author on five papers in refereed journals during the reporting period. A paper published in 2006 Jan included the JCA Director Ian George, and Dr. Lance Miller (Univ. Oxford) presented new evidence for orbital motion of material remarkably close to the central black hole in the active galaxy Mrk 766. The data yielded a mass constraint for the black hole that is one of the tightest to date due to the small radius within which the mass is constrained to lie. This result comprised a press release at the 2006 Jan AAS meeting in San Diego, and was covered by a number of newspapers inclusing USA Today. A later paper following up on this result in Mrk 766 found a tight correlation between line strength and continuum flux, confirming the production of strong Fe fluoresence from the inner accretion disk in active galaxies. In this period Dr. Turner was awarded Suzaku time on two bright active galaxies, NGC 5506 and Mrk 766, to search for additional X-ray signatures of material in the inner accretion disk. Dr. Turner also presented invited talks at three international meetings during this period.