A5013605475- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Radio Astronomy Observations and Technology
- Dark Matter and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Neutrino Physics Research
- Particle Accelerators and Free-Electron Lasers
- Particle Detector Development and Performance
- Pulsars and Gravitational Waves Research
- Particle physics theoretical and experimental studies
- Advanced Chemical Physics Studies
- Astronomical Observations and Instrumentation
- Phase Equilibria and Thermodynamics
- Gyrotron and Vacuum Electronics Research
- Magnetic confinement fusion research
- Global Energy and Sustainability Research
- Molecular Junctions and Nanostructures
- Computational Physics and Python Applications
- High-pressure geophysics and materials
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Galaxies: Formation, Evolution, Phenomena
- Satellite Image Processing and Photogrammetry
- Astronomy and Astrophysical Research
- Particle accelerators and beam dynamics
University of California, Los Angeles
2008-2022
Kavli Institute for Particle Astrophysics and Cosmology
2012
Stanford University
2012
SLAC National Accelerator Laboratory
2012
University of California, Santa Cruz
2009
University of Delaware
2008
General Atomics (United States)
2007
California Polytechnic State University
2007
Princeton University
2007
Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build next generation instrument, factor 5-10 improvement sensitivity 100 GeV 10 TeV range extension energies well below above TeV. will consist two arrays (one north, one south) for full sky coverage be operated as open observatory....
The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Although some AGN accelerate particles energies exceeding 10^12 electron Volts (eV) and are bright sources very-high-energy (VHE) gamma-ray emission, it not yet known where VHE emission originates. Here we report on radio observations galaxy M87, revealing period extremely strong flares accompanied by increase flux from its nucleus. These results...
This detection constrains the mechanism and emission region of gamma-ray radiation in pulsar’s magnetosphere.
We report the discovery of TeV gamma-ray emission from Type Ia supernova remnant (SNR) G120.1+1.4, known as Tycho's remnant. Observations performed in period 2008-2010 with VERITAS ground-based observatory reveal weak coming direction remnant, compatible a point source located at $00^{\rm h} \ 25^{\rm m} 27.0^{\rm s},\ +64^{\circ} 10^{\prime} 50^{\prime\prime}$ (J2000). The photon spectrum measured by can be described power-law $dN/dE = C(E/3.42\;\textrm{TeV})^{-\Gamma}$ $\Gamma 1.95 \pm...
We report on TeV γ-ray observations of the blazar Mrk 421 (redshift 0.031) with VERITAS observatory and Whipple 10 m Cherenkov telescope. The excellent sensitivity allowed us to sample fluxes energy spectra unprecedented accuracy where was detected in each pointings. A total 47.3 hr 96 data were acquired between 2006 January 2008 June. present results a study as function time for different flux levels. On May 2 3, bright flares reaching level Crab. complemented radio, optical, X-ray...
We present evidence that the very high energy (VHE, E > 100 GeV) gamma-ray emission coincident with supernova remnant IC 443 is extended. contains one of best studied sites remnant/molecular cloud interaction and pulsar wind nebula CXOU J061705.3+222127, both which are important targets for VHE observations. VERITAS observed 37.9 hr during 2007 detected above 300 GeV an excess 247 events, resulting in a significance 8.3 standard deviations (σ) before trials 7.5σ after point-source search....
Observations of radio halos and relics in galaxy clusters indicate efficient electron acceleration. Protons should likewise be accelerated and, on account weak energy losses, can accumulate, suggesting that may also sources very high (VHE; E > 100 GeV) gamma-ray emission. We report here VHE observations the Coma cluster with VERITAS array imaging Cerenkov telescopes, complementing Fermi Large Area Telescope at GeV energies. No significant emission from Cluster was detected. Integral flux...
The VERITAS array of Cherenkov telescopes has carried out a deep observational program on the nearby dwarf spheroidal galaxy Segue 1. We report results nearly 48 hours good quality selected data, taken between January 2010 and May 2011. No significant $\ensuremath{\gamma}$-ray emission is detected at nominal position 1, upper limits integrated flux are derived. According to recent studies, 1 most dark matter-dominated currently known. derive stringent bounds various annihilating decaying...
We report on the detection of a very rapid TeV gamma-ray flare from BL Lacertae 2011 June 28 with Very Energetic Radiation Imaging Telescope Array System (VERITAS). The flaring activity was observed during 34.6-minute exposure, when integral flux above 200 GeV reached $(3.4\pm0.6) \times 10^{-6} \;\text{photons}\;\text{m}^{-2}\text{s}^{-1}$, roughly 125% Crab Nebula measured by VERITAS. light curve indicates that observations missed rising phase but covered significant portion decaying...
The very high energy (VHE; E > 100 GeV) blazar Markarian 501 has a well-studied history of extreme spectral variability and is an excellent laboratory for studying the physical processes within jets active galactic nuclei. However, there are few detailed multiwavelength studies during its quiescent state, due to low luminosity. A short-term study was coordinated in March 2009, focusing around multi-day observation with Suzaku X-ray satellite including {\gamma}-ray data from VERITAS, MAGIC,...
The high-frequency-peaked BL Lacertae object 1ES 0229+200 is a relatively distant (z = 0.1396), hard-spectrum (Gamma ~ 2.5), very-high-energy-emitting (E > 100 GeV) gamma-ray blazar. Very-high-energy measurements of this active galactic nucleus have been used to place constraints on the intensity extragalactic background light and intergalactic magnetic field. A multi-wavelength study centered around very-high-energy observations by VERITAS presented. This obtained, over period three years,...
The intergalactic magnetic field (IGMF) in cosmic voids can be indirectly probed through its effect on electromagnetic cascades initiated by a source of TeV gamma-rays, such as active galactic nuclei (AGN). AGN that are sufficiently luminous at energies, "extreme blazars" produce detectable levels secondary radiation from inverse Compton (IC) scattering the electrons cascade, provided IGMF is not too large. We review recent work literature which utilizes this idea to derive constraints for...
The intermediate-frequency peaked BL Lacertae (IBL) object 3C 66A is detected during 2007 - 2008 in VHE (very high energy: E > 100 GeV) gamma-rays with the VERITAS stereoscopic array of imaging atmospheric Cherenkov telescopes. An excess 1791 events detected, corresponding to a significance 21.2 standard deviations (sigma), these observations (32.8 hours live time). observed integral flux above 200 GeV 6% Crab Nebula's and shows evidence for variability on time-scale days. measured energy...
We report on observations of very high energy γ rays from the shell-type supernova remnant (SNR) Cassiopeia A with Very Energetic Radiation Imaging Telescope Array System stereoscopic array four imaging atmospheric Cherenkov telescopes in Arizona. The total exposure time for these is 22 hr, accumulated between September and November 2007. γ-ray source associated SNR was detected above 200 GeV a statistical significance 8.3σ. estimated integral flux this about 3% Crab-Nebula flux. photon...
VERITAS, an Imaging Atmospheric Cherenkov Telescope (IACT) system for gammma‐ray astronomy in the GeV‐TeV range, has recently completed its first season of observations with a full array four telescopes. A number astrophysical gamma‐ray sources have been detected, both galactic and extragalactic, including previously unknown at TeV energies. We describe status some highlight results, assess technical performance, sensitivity shower reconstruction capabilities.
The high-frequency-peaked BL Lacertae object RGB J0710+591 was observed in the very high-energy (VHE; E > 100 GeV) wave band by VERITAS array of atmospheric Cherenkov telescopes. observations, taken between 2008 December and 2009 March totaling 22.1 hr, yield discovery VHE gamma rays from source. is detected at a statistical significance 5.5 standard deviations (5.5σ) above background, corresponding to an integral flux (3.9 +/- 0.8) x 10-12 cm-2 s-1 (3% Crab Nebula's flux) 300 GeV....
We report the detection of very-high-energy (VHE) gamma-ray emission from supernova remnant (SNR) G106.3+2.7. Observations performed in 2008 with VERITAS atmospheric Cherenkov telescope resolve extended overlapping elongated radio SNR. The 7.3 sigma (pre-trials) has a full angular extent roughly 0.6deg by 0.4deg. Most notably, centroid VHE is centered near peak coincident 12CO (J = 1-0) emission, 0.4deg away pulsar PSR J2229+6114, situated at northern end Evidently current-epoch particles...
We report the first detection of very-high-energy (VHE) gamma-ray emission above 140 GeV from PKS 1424+240, a BL Lac object with an unknown redshift. The photon spectrum measured by VERITAS is well described power law index 3.8 +- 0.5_stat 0.3_syst and flux normalization at 200 (5.1 0.9_stat 0.5_syst) x 10^{-11} TeV^-1 cm^-2 s^-1, where stat syst denote statistical systematical uncertainty, respectively. VHE steady over observation period between MJD 54881 55003 (2009 February 19 to June...
Indirect dark matter searches with ground-based gamma-ray observatories provide an alternative for identifying the particle nature of that is complementary to direct search or accelerator production experiments. We present results observations dwarf spheroidal galaxies Draco, Ursa Minor, Boötes 1, and Willman 1 conducted by Very Energetic Radiation Imaging Telescope Array System (VERITAS). These are nearby dominated objects located at a typical distance several tens kiloparsecs which there...
The VERITAS collaboration reports the detection of very-high-energy gamma-ray emission from high-frequency-peaked BL Lac object 1ES 1218+304 located at a redshift z = 0.182. A signal was detected with statistical significance 10.4 standard deviations (10.4σ) for observations taken during first three months 2007, confirming discovery this made by MAGIC collaboration. photon spectrum between ∼160 GeV and ∼1.8 TeV is well described power law an index Γ 3.08 ± 0.34stat 0.2sys. integral flux...
VERITAS has been monitoring the very-high-energy (VHE; >100GeV) gamma-ray activity of radio galaxy M87 since 2007. During 2008, flaring on a timescale few days was observed with peak flux (0.70 +- 0.16) X 10^{-11} cm^{-2} s^{-1} at energies above 350GeV. In 2010 April, detected flare from (2.71 0.68) for E>350GeV. The source six consecutive nights during flare, resulting in total 21 hr good quality data. most rapid variation occurred trailing edge an exponential decay time...