A. Furniss
A5058719199- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Radio Astronomy Observations and Technology
- Dark Matter and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Particle Detector Development and Performance
- Neutrino Physics Research
- Particle Accelerators and Free-Electron Lasers
- Pulsars and Gravitational Waves Research
- Solar and Space Plasma Dynamics
- Galaxies: Formation, Evolution, Phenomena
- Astronomical Observations and Instrumentation
- Particle physics theoretical and experimental studies
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Photocathodes and Microchannel Plates
- Particle accelerators and beam dynamics
- Astro and Planetary Science
- Cosmology and Gravitation Theories
- Genetics, Bioinformatics, and Biomedical Research
- Computational Physics and Python Applications
- Planetary Science and Exploration
- Biomedical and Engineering Education
- Atmospheric Ozone and Climate
- Astrophysics and Star Formation Studies
California State University, East Bay
2015-2024
California State University System
2024
University of California, Santa Cruz
2008-2023
Universidad Veritas
2015-2023
University of California, Los Angeles
2011-2022
Istituto Nazionale di Fisica Nucleare
2022
Southern University and Agricultural and Mechanical College
2021
Columbia University
2011-2021
Istituto Nazionale di Fisica Nucleare, Sezione di Bari
2021
Center for Astrophysics Harvard & Smithsonian
2011-2020
The third catalog of active galactic nuclei (AGNs) detected by the Fermi-LAT (3LAC) is presented. It based on (3FGL) sources between 100 MeV and 300 GeV with a Test Statistic (TS) greater than 25, 2008 August 4 2012 July 31. 3LAC includes 1591 AGNs located at high Galactic latitudes (|b|>10{\deg}), 71% increase over second 2 years data. There are 28 duplicate associations, thus 1563 2192 high-latitude gamma-ray 3FGL AGNs. Most them (98%) blazars. About half newly blazars unknown type, i.e.,...
We present a catalog of sources detected above 50 GeV by the {\it Fermi}-Large Area Telescope (LAT) in 80 months data. The newly delivered Pass 8 event-level analysis allows detection and characterization GeV--2 TeV energy range. In this band, Fermi}-LAT has 360 sources, which constitute second hard (2FHL). improved angular resolution enables precise localization point ($\sim$1.7$'$ radius at 68 % C.~L.) spatially extended sources. find that 86 can be associated with counterparts other...
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 results of a multi-band observing campaign on famous blazar 3C 279 conducted during phase increased activity from 2013 December to 2014 April, including first observations it with NuSTAR. The $\gamma$-ray emission source measured by Fermi-LAT showed multiple distinct flares reaching highest flux level in this object since beginning Fermi mission, $F(E > 100\,{\rm MeV})$ $10^{-5}$ photons cm$^{-2}$ s$^{-1}$, and doubling time scale as short 2 hours. spectrum one was very hard,...
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 present the first installment of H I sources extracted from Arecibo Legacy Fast ALFA (ALFALFA) extragalactic survey, initiated in 2005. Sources have been three-dimensional spectral data cubes exploiting a matched filtering technique and then examined interactively to yield global parameters. A total 730 detections are cataloged within solid angle 11h44m < R.A. (J2000.0) 14h00m +12° decl. +16° redshift range -1600 km s-1 cz 18,000 s-1. In comparison, Parkes All-Sky Survey detected 40...
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....
We present coordinated multiwavelength observations of the bright, nearby BL Lac object Mrk 421 taken in 2013 January-March, involving GASP-WEBT, Swift, NuSTAR, Fermi-LAT, MAGIC, VERITAS, and other collaborations instruments, providing data from radio to very-high-energy (VHE) gamma-ray bands. NuSTAR yielded previously unattainable sensitivity 3-79 keV range, revealing that spectrum softens when source is dimmer until X-ray spectral shape saturates into a steep power law with photon index...
We present constraints on the annihilation cross section of weakly interacting massive particles dark matter based joint statistical analysis four dwarf galaxies with VERITAS. These results are derived from an optimized photon weighting technique that improves standard imaging atmospheric Cherenkov telescope (IACT) analyses by utilizing spectral and spatial properties individual events. report $\ensuremath{\sim}230$ hours observations five galaxies. find no evidence gamma-ray emission any...
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,...
Outbursts from gamma-ray quasars provide insights on the relativistic jets of active galactic nuclei and constraints diffuse radiation fields that fill universe. The detection significant emission above 100 GeV a distant quasar would show some radiated gamma-rays escape pair-production interactions with low-energy photons, be it extragalactic background light (EBL), or near supermassive black hole lying at jet's base. VERITAS detected up to ∼200 PKS 1441+25 (z = 0.939) during 2015 April,...
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,...
High-energy gamma-ray emission from supernova remnants (SNRs) has provided a unique perspective for studies of Galactic cosmic-ray acceleration. Tycho's SNR is particularly good target because it young, type Ia that well-studied over wide range energies and located in relatively clean environment. Since the detection by VERITAS Fermi-LAT, there have been several theoretical models proposed to explain its broadband high-energy morphology. We report on an update measurements with 147 hours 84...
The Galactic Center (GC) region hosts a variety of powerful astronomical sources and rare astrophysical processes that emit large flux non-thermal radiation. inner 375 pc x 600 region, called the Central Molecular Zone, is home to supermassive black hole Sagittarius A*, massive cloud complexes, particle accelerators such as supernova remnants. We present results our improved analysis very-high-energy (VHE) gamma-ray emission above 2 TeV from GC using 125 hours data taken with VERITAS...
The large-scale Universal structure comprises strands of dark matter and galaxies with large under-dense volumes known as voids. We measure the fraction line sight that intersects voids for active galactic nuclei (AGN) detected by Fermi Large Area Telescope (LAT) quasars from Sloan Digital Sky Survey (SDSS). This ``voidiness'' is a rudimentary proxy density along to galaxies. voidiness SDSS-observed (QSOs) distinctly different randomly distributed source populations, median p-value...
Abstract The large-scale universal structure comprises strands of dark matter and galaxies with large underdense volumes known as voids. We measure the fraction line sight that intersects voids for active galactic nuclei (AGN) detected by Fermi Large Area Telescope (LAT) quasars from Sloan Digital Sky Survey (SDSS). This “voidiness” is a rudimentary proxy density along to galaxies. voidiness SDSS-observed (QSOs) distinctly different randomly distributed source populations, median p -value...
We report results from an intensive multiwavelength campaign on the intermediate-frequency-peaked BL Lacertae object W Com (z=0.102) during a strong outburst of very high energy gamma-ray emission in June 2008. The signal was detected by VERITAS 2008 7-8 with flux F(>200 GeV) = (5.7+-0.6)x10^-11 cm-2s-1, about three times brighter than discovery March. initial detection this flare at energies above 200 GeV followed observations gamma-rays (AGILE, E>100 MeV), and X-rays (Swift XMM-Newton),...
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...
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.