Day: August 9, 2013

Hao Zhou Research

HAWC Experiment
Figure 1: The HAWC experiment as of July 26, 2013. The full array will cover the whole plane in the center of the picture.

I am working with Dr. Petra Huentemeyer on the HAWC (short for High Altitude Water Cherenkov) experiment, a very high energy (VHE) gamma-ray observatory currently being built in Mexico. In contrast to optical or radio waves, gamma-ray photons cannot penetrate the Earth’s atmosphere. Instead they collide with particles in the atmosphere and create showers of secondary particles through electromagnetic and hadronic interactions. Once completed the HAWC experiment will consist of 300 water Cherenkov detectors (WCDs), that will measure these secondary particles as they sweep through the array. The directions of the primary gamma-ray photons are reconstructed using the time between the signals in each WCD. Thus timing calibration, which is what I am currently working on, is crucial for good angular resolution. As of now, more than one third of the array is finished and operational. At the moment, I am doing a preliminary analysis of data collected with this sub-array. Figure 1 shows a picture of HAWC on July 26, 2013. My research is focusing on pulsar wind nebulae (PWNe), the largest class of galactic VHE gamma-ray sources. PWNe produce electromagnetic radiation in a very broad energy range from radio to VHE gamma rays, and thereby provide an excellent laboratory to study the physical processes at very high energy. Figure 2 shows the crab nebula at different wavelengths. Using data collected with the complete HAWC array, I will reconstruct the energy spectrum of gamma rays emitted by PWNe. I will combine my analysis results with data from other experiments that take measurements at lower energies, to reveal the physics processes occurring in PWNe.

by Hao Zhou

Crab Nebula
Figure 2: Crab nebula in radio (red), optical (green) and X-ray (blue) from APOD (Astronomy Picture of the Day) on September 20, 2002. Credit: J. Hester (ASU), CXC, HST, NRAO, NSF, NASA

SURF Presentations August 12 and 13, 2013

Recipients of Summer Undergraduate Research Fellowships (SURFs) will present end-of-summer project updates Monday and Tuesday (Aug. 12 and 13), from 9 to 11 a.m., in Fisher 139.

From Tech Today.

SURF award recipients in physics include:

Joseph Charnawskas
Advisor: Raymond Shaw
The Effects of the Gravitational Force on Water Particles in a Turbulent Flow

Mick Small
Advisor: Yoke Khin Yap
Photovoltaic Responses of Quantum Dot Sensitized ZnO Nanowires

Angela Small (Honor’s Institute)
Advisor: Jacek Borysow
Analysis of Artificial Breath Samples Using Raman Spectroscopy for Medical Diagnosis

Kevin Rocheleau (Honor’s Institute)
Advisor: Petra Huentemeyer
Analysis and Modeling of Diffuse Gamma-Ray Emission from the Cygnus Region using FERMI and HAWC Data