7 research outputs found
Current Status of VHE Astronomy
Very-high-energy astronomy studies the Universe at energies between 30 GeV
and 100 TeV. The past decade has seen enormous progress in this field. There
are now at least seven known sources of VHE photons. By studying these objects
in the VHE regime one can begin to understand the environments surrounding
these objects, and how particle acceleration is realized in nature. In addition
the photon beams from the extragalactic gamma-ray sources can be used to study
the electromagnetic fields in the intervening space. This recent progress can
be traced to the development of a new class of detector with the ability to
differentiate between air showers produced by gamma rays and those produced by
the much more numerous hadronic cosmic-ray background. Much more sensitive
instruments are currently in the design phase and two new types of instruments
are beginning to take data. In this paper we will discuss the physics of these
sources and describe the existing and planned detectors.Comment: 7 pages, 3 figure
Search for Short Duration Bursts of TeV Gamma Rays with the Milagrito Telescope
Abstract The Milagrito water Cherenkov telescope operated for over a year (2/97-5/98). The most probable gamma-ray energy was ~1 TeV and the trigger rate was as high as 400 Hz. Milagrito has opened a new window on the TeV Universe. We have developed an efficient technique for searching the entire sky for short duration bursts of TeV photons. Such bursts may result from "traditional" gamma-ray bursts that were not in the field-of-view of any other instruments, the evaporation of primordial black holes, or some as yet undiscovered phenomenon. We have begun to search the Milagrito data set for bursts of duration 10 seconds. Here we will present the technique and the expected results. Final results will be presented at the conference
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
Monitoring the Northern Sky for Sources of TeV Gamma Rays
Abstract At the present time there are fewer then 10 confirmed sources of TeV gamma rays. While this lack of sources is partially due to the sensitivity of current instruments, it may also be due to the small field-of-view of current instruments coupled with the transient nature of astrophysical sources of TeV gamma rays. Milagro is a new type of extensive air shower array that uses water as the detecting medium and has the ability to continuously monitor the entire overhead sky for transient and steady sources of TeV gamma rays. Here the analysis of 2.4 years of data searching for steady TeV gamma-ray emission in the northern hemisphere is presented. Two sources have been detected: the Crab nebula and Mrk 421. A third region at a location of 79.44 ± 1.0 ra and 26.26 ± 0.7 declination is the third brightest region in the northern sky. After accounting for the trials associated with searching the entire northern hemisphere this region is not statistically significant. At the conference results from searches for transient emission on timescales of 1 week and greater will be presented
The High-Altitude water cherenkov (HAWC) observatory in México: The primary detector
The High-Altitude Water Cherenkov (HAWC) observatory is a second-generation continuously operated, wide field-of-view, TeV gamma-ray observatory. The HAWC observatory and its analysis techniques build on experience of the Milagro experiment in using ground-based water Cherenkov detectors for gamma-ray astronomy. HAWC is located on the Sierra Negra volcano in México at an elevation of 4100 meters above sea level. The completed HAWC observatory principal detector (HAWC) consists of 300 closely spaced water Cherenkov detectors, each equipped with four photomultiplier tubes to provide timing and charge information to reconstruct the extensive air shower energy and arrival direction. The HAWC observatory has been optimized to observe transient and steady emission from sources of gamma rays within an energy range from several hundred GeV to several hundred TeV. However, most of the air showers detected are initiated by cosmic rays, allowing studies of cosmic rays also to be performed. This paper describes the characteristics of the HAWC main array and its hardware.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Físic
Combined dark matter searches towards dwarf spheroidal galaxies with Fermi-LAT, HAWC, H.E.S.S., MAGIC, and VERITAS
Cosmological and astrophysical observations suggest that 85\% of the total matter of the Universe is made of Dark Matter (DM). However, its nature remains one of the most challenging and fundamental open questions of particle physics. Assuming particle DM, this exotic form of matter cannot consist of Standard Model (SM) particles. Many models have been developed to attempt unraveling the nature of DM such as Weakly Interacting Massive Particles (WIMPs), the most favored particle candidates. WIMP annihilations and decay could produce SM particles which in turn hadronize and decay to give SM secondaries such as high energy rays. In the framework of indirect DM search, observations of promising targets are used to search for signatures of DM annihilation. Among these, the dwarf spheroidal galaxies (dSphs) are commonly favored owing to their expected high DM content and negligible astrophysical background. In this work, we present the very first combination of 20 dSph observations, performed by the Fermi-LAT, HAWC, H.E.S.S., MAGIC, and VERITAS collaborations in order to maximize the sensitivity of DM searches and improve the current results. We use a joint maximum likelihood approach combining each experiment's individual analysis to derive more constraining upper limits on the WIMP DM self-annihilation cross-section as a function of DM particle mass. We present new DM constraints over the widest mass range ever reported, extending from 5 GeV to 100 TeV thanks to the combination of these five different -ray instruments