Search for TeV emission from geminga by the VERITAS observatory

Journal ArticleDuring November/December 2007, we observed the region centered on the Geminga Pulsar for 10.4 hours using the VERITAS IACT Observatory. We find no evidence for either steady emission point source emission, or pulsed emission of a point source at the period of the Geminga pulsar (237 msec). The measured VHE y-ray flux limits for the impulsed search is Fy(> 300 GeV , 99% c.l) lOOGeV , 99%c.l.) < 0.8 - 1.0 x 10-8 m-2 s"1

Gamma-ray emission by the BL Lac Markarian 501

posterOptical astronomy is the study of the heavens as they emit light, or the visible portion of the electromagnetic spectrum. Gamma-ray astronomy is the study of astrophysical sources that emit the most energetic form of electromagnetic radiation (ie: gamma-rays). High Energy gamma-rays are much too faint to be directly seen with the human eye. Thus they are detected using arrays of large diameter (39 ft) mirrors and fast digitizing cameras which image the light emitted from the gamma-ray as it is absorbed in the Earth's atmosphere

Simulation of Near Horizontal Muons and Muon Bundles for the HAWC Observatory with CORSIKA

The HAWC (High Altitude Water Cerenkov) gamma ray observatory observes muons with nearly-horizontal trajectories corresponding to zenith angles greater than $80^{0}$. HAWC is located at an altitude of 4100 meters a.s.l. (70 deg. atmospheric depth of 2400 g/cm$^{2}$) on the extinct volcano, Sierra Negra in Mexico. In this poster, we summarize the CORSIKA and GEANT4 as well as toy-model based simulations performed to determine the effective area of HAWC to muons from high zenith angle cosmic ray primaries. We are developing an updated GEANT4 based detector response simulation that includes a model of the volcanoes that are located near HAWC. These simulations are investigating the capability to use muon multiplicity and rates to differentiate between the primary particle composition (proton or iron) and measure the primary energy.Comment: Presented at the 35th International Cosmic Ray Conference (ICRC2017), Bexco, Busan, Korea. See arXiv:1708.02572 for all HAWC contribution

Deployment of a pair of 3M telescopes in Utah

Journal ArticleTwo 3m telescopes are being installed in Grantsville Utah. They are intended for the testing of various approaches to the implementation of intensity interferometry using Cherenkov Telescopes in large arrays as receivers as well as for the testing of novel technology cameras and electronics for ground based gamma-ray astronomy

Detection of Near Horizontal Muons with the HAWC Observatory

The HAWC (High Altitude Water Cherenkov) gamma ray observatory is able to observe muons with nearly horizontal trajectories. HAWC is located at an altitude of 4100 meters a.s.l. on the Sierra Negra volcano in Mexico. The HAWC detector is composed of 300 water tanks, each 7.3 m in diameter and 4.5 m tall, densely packed over a physical area of 22,000 m$^{2}$. Previous and current experiments have observed high zenith angle (near horizontal) muons at or near sea level. HAWC operates as a hodoscope able to observe multi-TeV muons at zenith angles greater than 75 degrees. This is the first experiment to measure near horizontal muons at high altitude and with large ($\geq$ 10 m) separations for multiple muons. These muons are distinguishable from extensive air showers by observing near horizontal particles propagating with the speed of light. The proximity of Sierra Negra and Pico de Orizaba volcanoes provides an additional measurement of muons with rock overburdens of several km water equivalent. We will present the angular distribution and rate at which HAWC observes these muon eventsComment: Presented at the 35th International Cosmic Ray Conference (ICRC2017), Bexco, Busan, Korea. See arXiv:1708.02572 for all HAWC contribution

Search for γ rays above 1014 eV from Cygnus X-3 during the June and July 1989 radio outbursts

Journal ArticleWe have looked for γ-ray emission above 100 TeV from the binary x-ray source Cygnus X-3 during a period of intense radio emission in the summer of 1989. We find no evidence for excess air showers from the direction of the source and the muon content of air showers from this direction is the same as that of ordinary cosmic rays. The flux of γ rays from Cygnus X-3 with energies exceeding 2.1x10^14 eV is < 5.5x10^-13 cm-1 sec-1 (90% C.L.)

Observation of the shadows of the moon and sun using 100 TeV cosmic rays

Journal ArticleThe Chicago Air Shower Array (CASA) is a large ground-based scintillation detector [1-4]. It is located at the Dugway Proving Ground is west central Utah, latitude 40°N and mean atmospheric depth 870 g / c m 2. A schematic aerial view of CASA is shown in Fig. 1. Each dot represents one scintillation station of the array

Toward a revival of stellar intensity interferometry

Journal ArticleBuilding on technological developments over the last 35 years, intensity interferometry now appears a feasible option by which to achieve diffraction-limited imaging over a square-kilometer synthetic aperture. Upcoming Atmospheric Cherenkov Telescope projects will consist of up to 100 telescopes, each with ~100m2 of light gathering area, and distributed over ~lkm2 . These large facilities will offer thousands of baselines from 50m to more than 1km and an unprecedented (u,v) plane coverage. The revival of interest in Intensity Interferometry has recently led to the formation of a IAU working group. Here we report on various ongoing efforts towards implementing modern Stellar Intensity Interferometry

Overview of the ANITA project

Journal ArticleThe ANITA project is designed to investigate ultra-high energy (>1017 eV) cosmic ray interactions throughout the universe by detecting the neutrinos created in those interactions. These high energy neutrinos are detectable through their interactions within the Antarctic ice sheet, which ANITA will use as a detector target that effectively converts the neutrino interactions to radio pulses. This paper will give an overview of the project including scientific objectives, detection description and mission design

Antarctic impulsive transient antenna (ANITA) instrumentation

Journal ArticleWe will report on the details of the ANITA instrument. This instrument is fundamentally a broadband antenna, which is arrayed and constructed in such a way as to be optimized for the detection and characterization of high-energy neutrino cascades [1]. The requirement to maximize the detector view of the Antarctic ice fields implies low gain antennas yet the need for maximum sensitivity dictates using the highest gain possible. Since the Cherenkov signal increases quadratically at higher frequencies suggesting that the optimal selection is an antenna with constant gain as a function of frequency. The baseline design will be a linearly polarized log-periodic zigzag (LPZZ) antenna