I am currently working on the Gamma-Ray Observatory known as HAWC (http://hawc.umd.edu). The HAWC detector is a wide-field of view continuously operating gamma ray telescope consisting of 300 large Water Cerenkov Detectors located on the Sierra Negra mountain in Mexico at an altitude of 4100 m. HAWC will be sensitive to gamma rays with energies between 100 Gev and above approximately 100 TEV and will perform an “all-sky” survey of the gamma-ray sky. HAWC will be capable of observing both point sources of gamma-rays, including Gamma Ray Bursts (GRBs), as well as the diffuse gamma-ray background. This diffuse background may be related to the sources of cosmic-ray acceleration. I am studying the cosmic-ray events as observed in HAWC as a means of understanding this background to the gamma-ray events, as well as measure the energy spectra and any possible anisotropy in the arrival directions of the cosmic ray events.
In the past few years I have also been heavily involved in developing an optical astronomy program at the University of Utah. I headed the effort to construct an astronomical observatory for the University of Utah located at a dark-sky site in Southern Utah. I secured a $700,000+ grant to procure a 32” diameter optical telescope. I performed site surveys and characterization studies throughout the mountains of Southern Utah and have found a suitable site. Construction of the Observatory started in July 2009 and was completed in only 3 months. Commissioning and “first-light” occurred in October, 2009. During Summer 2010, work on the development of remote operation capabilities and further characterization of the site has taken place. Colleagues and I used the observatory facility for coursework in the Fall 2010 semester. We are working toe further develop this facility so that it can be utilized to support research activities for the Sloan Digital Sky Survey program that the University of Utah has recently joined. It will also be used carry out a program of research in fields such as GRB follow-up observations, extra-solar planetary studies and supernovae searches. This facility will also be used for public outreach and educational purposes.
Since my arrival at the University of Utah in 1997, my research interests have been in the field of Ultra High Energy Cosmic Ray (UHECR) Physics. I played a major role in commissioning and operating the HiRes detector as well as helping to provide computing and software support to the entire HiRes collaboration. I was involved in the development of reconstruction and simulation software that was used in nearly all of the published research results of the HiRes collaboration. While on HiRes, I supervised the Ph.D thesis research of two students who have continued on to successful research positions. One of the major achievements of the HiRes experiment has been the observation of the so-called “GZK cutoff” in the energy spectrum of UHECR particles.
I have continued working in the field of UHECR physics and have been involved with the Telescope Array (TA) project that has been taking UHECR data since shortly after the HiRes detector was decommissioned. One of the major goals for TA is the resolution of the discrepancy in the measurements by AGASA and HiRes of the UHECR spectrum. The measurements of AGASA indicated that the UHECR spectrum continue unabated beyond the purported GZK cutoff. The measurements of the UHECR spectrum from HiRes support the existence of the GZK cutoff. AGASA utilized an array of ground based scintillator detectors to measure the properties of UHECRs by sampling the particles from an extensive air shower on the ground. The HiRes detector utilized what is known as the air fluorescence technique to measure the properties of the UHECRs. The telescope array project combines the complementary measurement techniques used by AGASA and HiRes into a single experiment. In this manner the two measurement techniques can be directly compared and the discrepancy thereby resolved.
I was trained as an experimental high-energy physicist and worked at the European Laboratory for Particle Physics (CERN) on the OPAL experiment at the Large Electron- Positron Accelerator (LEP). There I was involved in the design, construction and implementation of several of the detector components of the OPAL experiment. The topic of my Ph.D research was the measurement of the coupling of the b quark to the Z boson. As a postdoctoral scientist, I worked on precision measurements of the electroweak parameters, such as the mass and width of the Z boson and its coupling to quarks and leptons. Much of my effort was devoted to the measurement of the luminosity delivered to the OPAL experiment. The luminosity measurements were of critical importance to the measurements of the parameters of the electroweak sector of the Standard Model of Particle Physics. I was also involved in the Higgs Boson search analysis at LEP as well as the development of analysis plans for Higgs Searches at Atlas.
- University of Utah Dept. of Physics and Astronomy Colloquium entitled "The HAWC (High Altitude Water Cerenkov) Gamma Ray Observatory".
- Michael Newbold, Graduate Student. Physics. 01/01/2012 - present.
- Ahron Barber, Graduate Student. Physics. 01/01/2011 - present.
Lived/worked in Pays de Gex from 1988-1997.
Currently working on the HAWC gamma ray observatory located on Pico di Orizaba.
Worked at particle physics laboratory, CERN, from 1988-1997.
- Milagro Limits and HAWC Sensitivity for the Rate-Density of Evaporating Primordial Black Holes HAWC Collaboration (A.A. Abdo et al.). Published in Astropart.Phys. 64 (2015).
- Study of Ultra-High Energy Cosmic Ray composition using Telescope Array’s Middle Drum detector and surface array in hybrid mode. The Telescope Array Collaboration (R.U.Abbasi et al.).. Aug 7, 2014. 13 pp. Published in Astropart.Phys. 64 (2014) 49-62.
- VAMOS: a Pathfinder for the HAWC Gamma-Ray Observatory. The HAWC Collaboration (A.U. Abeysekara et al.). Aug 15, 2014. 8 pp. Published in Astropart.Phys. 62 (2015) 125-133.
- Search for gamma-rays from the unusually bright GRB 130427A with the HAWC Gamma-ray Observatory The HAWC Collaboration (A.U. Abeysekara et al.). Astrophys. J. 800 (2015), 78.
- Observation of Small-scale Anisotropy in the Arrival Direction Distribution of TeV Cosmic Rays with HAWC. The HAWC Collaboration (A.U. Abeysekara et al.). Aug 20, 2014. 12 pp. Astrophys. J. 796 (2014), 108.
- The Energy Spectrum of Telescope Array's Middle Drum Detector and the Direct Comparison to the High Resolution Fly's Eye Experiment Astropart.Phys. 39-40 (2012) 109-119.
- The surface detector array of the Telescope Array experiment Nucl.Instrum.Meth. A689 (2012) 87-97.
- Search for Anisotropy of Ultra-High Energy Cosmic Rays with the Telescope Array Experiment Astrophys.J. 757 (2012) 26.
- New air fluorescence detectors employed in the Telescope Array experiment Nucl.Instrum.Meth. A676 (2012) 54-65.
- On the sensitivity of the HAWC observatory to gamma-ray bursts Astropart.Phys. 35 (2012) 641-650.