Results for "J. McEnery"

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HAWC: A Next Generation All-Sky VHE Gamma-Ray TelescopeMar 03 2004The study of the universe at energies above 100 GeV is a relatively new and exciting field. The current generation of pointed instruments have detected TeV gamma rays from at least 10 sources and the next generation of detectors promises a large increase ... More
GLAST: Understanding the High Energy Gamma-Ray SkyJun 09 2004We discuss the ability of the GLAST Large Area Telescope (LAT) to identify, resolve, and study the high energy gamma-ray sky. Compared to previous instruments the telescope will have greatly improved sensitivity and ability to localize gamma-ray point ... More
New Limits to the IR Background: Bounds on Radiative Neutrino Decay and on VMO Contributions to the Dark Matter ProblemFeb 18 1998From considering the effect of gamma-gamma interactions on recently observed TeV gamma-ray spectra, improved limits are set to the density of extragalactic infrared (IR) photons which are robust and essentially model-independent. The resulting limits ... More
Limits to Quantum Gravity Effects from Observations of TeV Flares in Active GalaxiesOct 13 1998We have used data from the TeV gamma-ray flare associated with the active galaxy Markarian 421 observed on 15 May 1996 to place bounds on the possible energy-dependence of the speed of light in the context of an effective quantum gravitational energy ... More
Neutrinos, Cosmic Rays and the MeV BandMar 13 2019The possible association of the blazar TXS 0506+056 with a high-energy neutrino detected by IceCube holds the tantalizing potential to answer three astrophysical questions: 1. Where do high-energy neutrinos originate? 2. Where are cosmic rays produced ... More
GRB 131014A: a Laboratory to Study the Thermal-Like and Non-Thermal Emissions in Gamma-Ray Bursts, and the new L$_\mathrm{i}^\mathrm{nTh}$-E$_\mathrm{peak,i}^\mathrm{nTh,rest}$ relationJul 24 2015Evidence has been accumulated on the existence of a thermal-like component during the prompt phase of GRBs. This component, often associated with the GRB jet's photosphere, is usually subdominant compared to a much stronger non-thermal one. The prompt ... More
Tev Observations of the Variability and Spectrum of Markarian 421Jun 13 1997Markarian 421 was the first extragalactic source to be detected with high statistical certainty at TeV energies. The Whipple Observatory gamma-ray telescope has been used to observe the Active Galactic Nucleus, Markarian 421 in 1996 and 1997. The rapid ... More
CGRO/BATSE Data Support the New Paradigm for GRB Prompt Emission and the New L$_{i}^{nTh}$-E$_{peak,i}^{nTh,rest}$ relationJul 15 2015The paradigm for GRB prompt emission is changing. Since early in the CGRO era, the empirical Band function has been considered a good description of the keV-MeV spectra although its shape is very often inconsistent with the predictions of the pure synchrotron ... More
The Flux Variability of Markarian 501 in Very High Energy Gamma RaysMar 05 1999The BL Lacertae object Markarian 501 was identified as a source of gamma-ray emission at the Whipple Observatory in March 1995. Here we present a flux variability analysis on several times-scales of the 233 hour data set accumulated over 213 nights (from ... More
Energetic Particles of Cosmic Accelerators I: Galactic AcceleratorsMar 11 2019The high-energy universe has revealed that energetic particles are ubiquitous in the cosmos and play a vital role in the cultivation of cosmic environments on all scales. Energetic particles in our own galaxy, galactic cosmic rays (GCRs), engage in a ... More
Energetic Particles of Cosmic Accelerators II: Active Galactic Nuclei and Gamma-ray BurstsMar 11 2019The high-energy universe has revealed that energetic particles are ubiquitous in the cosmos and play a vital role in the cultivation of cosmic environments on all scales. Though they play a key role in cultivating the cosmological environment and/or enabling ... More
High-Energy Polarimetry - a new window to probe extreme physics in AGN jetsMar 11 2019The constantly improving sensitivity of ground-based and space-borne observatories has made possible the detection of high-energy emission (X-rays and gamma-rays) from several thousands of extragalactic sources. Enormous progress has been made in measuring ... More
A Unified Model for GRB Prompt Emission from Optical to Gamma-Rays; a New Type of Standard CandleJun 23 2016The origin of prompt emission from gamma ray bursts remains to be an open question. Correlated prompt optical and gamma-ray emission observed in a handful of GRBs strongly suggests a common emission region, but failure to adequately fit the broadband ... More
Swift and Fermi observations of X-ray flares: the case of Late Internal ShockNov 05 2014Simultaneous Swift and Fermi observations of gamma-ray bursts (GRBs) offer a unique broadband view of their afterglow emission, spanning more than ten decades in energy. We present the sample of X-ray flares observed by both Swift and Fermi during the ... More
Supermassive black holes at high redshiftsMar 14 2019MeV blazars are the most luminous persistent sources in the Universe and emit most of their energy in the MeV band. These objects display very large jet powers and accretion luminosities and are known to host black holes with a mass often exceeding $10^9 ... More
Detection of a Thermal Spectral Component in the Prompt Emission of GRB 100724BOct 22 2010Nov 30 2010Observations of GRB 100724B with the Fermi Gamma-Ray Burst Monitor (GBM) find that the spectrum is dominated by the typical Band functional form, which is usually taken to represent a non-thermal emission component, but also includes a statistically highly ... More
Quantum PlasmonicsDec 24 2013Quantum plasmonics is a rapidly growing field of research that involves the study of the quantum properties of light and its interaction with matter at the nanoscale. Here, surface plasmons - electromagnetic excitations coupled to electron charge density ... More
The e-ASTROGAM gamma-ray space missionAug 12 2016Jan 31 2017The e-ASTROGAM is a gamma-ray space mission to be proposed as the M5 Medium-size mission of the European Space Agency. It is dedicated to the observation of the Universe with unprecedented sensitivity in the energy range 0.2 - 100 MeV, extending up to ... More
Gamma-Ray Summary ReportJan 10 2002This paper reviews the field of gamma-ray astronomy and describes future experiments and prospects for advances in fundamental physics and high-energy astrophysics through gamma-ray measurements. We concentrate on recent progress in the understanding ... More
Compton-Pair Production Space Telescope (ComPair) for MeV Gamma-ray AstronomyAug 28 2015Sep 18 2015The gamma-ray energy range from a few hundred keV to a few hundred MeV has remained largely unexplored, mainly due to the challenging nature of the measurements, since the pi- oneering, but limited, observations by COMPTEL on the Compton Gamma-Ray Observatory ... More
Cosmic Rays and Interstellar Medium with Gamma-Ray Observations at MeV EnergiesMar 13 2019Latest precise cosmic-ray (CR) measurements and present gamma-ray observations have started challenging our understanding of CR transport and interaction in the Galaxy. Moreover, because the density of CRs is similar to the density of the magnetic field, ... More
Pulsar Simulations for the Fermi Large Area TelescopeJul 01 2009Pulsars are among the prime targets for the Large Area Telescope (LAT) aboard the recently launched Fermi observatory. The LAT will study the gamma-ray Universe between 20 MeV and 300 GeV with unprecedented detail. Increasing numbers of gamma-ray pulsars ... More
Towards a Better Understanding of the GRB Phenomenon: a New Model for GRB Prompt Emission and its effects on the New Non-Thermal L$_\mathrm{i}^\mathrm{NT}$-E$_\mathrm{peak,i}^\mathrm{rest,NT}$ relationJan 28 2015We reanalyze the prompt emission of two of the brightest Fermi GRBs (080916C and 090926A) with a new model composed of 3 components: (i) a thermal-like component--approximated with a black body (BB)--interpreted as the jet photosphere emission of a magnetized ... More
Evidence for a Photospheric Component in the Prompt Emission of the Short GRB120323A and its Effects on the GRB Hardness-Luminosity RelationOct 26 2012Apr 07 2013The short GRB 120323A had the highest flux ever detected with the Fermi/GBM. Here we study its remarkable spectral properties and their evolution using two spectral models: (i) a single emission component scenario, where the spectrum is modeled by the ... More
Fermi Large Area Telescope Observations of the Active Galaxy 4C +55.17: Steady, Hard Gamma-Ray Emission and its ImplicationsJul 07 2011We report Fermi/LAT observations and broad-band spectral modeling of the radio-loud active galaxy 4C +55.17 (z=0.896), formally classified as a flat-spectrum radio quasar. Using 19 months of all-sky survey Fermi/LAT data, we detect a gamma-ray continuum ... More
Fermi and Swift Gamma-Ray Burst Afterglow Population StudiesJun 13 2011The new and extreme population of GRBs detected by Fermi-LAT shows several new features in high energy gamma-rays that are providing interesting and unexpected clues into GRB prompt and afterglow emission mechanisms. Over the last 6 years, it has been ... More
HAWC Contributions to the 35th International Cosmic Ray Conference (ICRC2017)Aug 08 2017Aug 18 2017List of proceedings from the HAWC Collaboration presented at the 35th International Cosmic Ray Conference, 12 July - 20 July 2017, Bexco, Busan, Korea.
The e-ASTROGAM gamma-ray space observatory for the multimessenger astronomy of the 2030sMay 16 2018Jul 13 2018e-ASTROGAM is a concept for a breakthrough observatory space mission carrying a gamma-ray telescope dedicated to the study of the non-thermal Universe in the photon energy range from 0.15 MeV to 3 GeV. The lower energy limit can be pushed down to energies ... More
Quasar X-ray jets: Gamma-ray diagnostics of the synchrotron and inverse Compton hypotheses, the case of 3C 273Oct 27 2006The process responsible for the Chandra-detected X-ray emission from the large scale jets of powerful quasars is a matter of ongoing debate. The two main contenders are external Compton (EC) scattering off the cosmic microwave background (CMB) photons ... More
Milagro Limits and HAWC Sensitivity for the Rate-Density of Evaporating Primordial Black HolesJul 07 2014Oct 06 2014Primordial Black Holes (PBHs) are gravitationally collapsed objects that may have been created by density fluctuations in the early universe and could have arbitrarily small masses down to the Planck scale. Hawking showed that due to quantum effects, ... More
Search for cosmic-ray induced gamma-ray emission in Galaxy ClustersAug 26 2013Mar 24 2014Current theories predict relativistic hadronic particle populations in clusters of galaxies in addition to the already observed relativistic leptons. In these scenarios hadronic interactions give rise to neutral pions which decay into $\gamma$ rays, that ... More
Time resolved spectroscopy of SGR J1550-5418 bursts detected with Fermi/GBMFeb 24 2014We report on time-resolved spectroscopy of the 63 brightest bursts of SGR J1550-5418, detected with Fermi/Gamma-ray Burst Monitor during its 2008-2009 intense bursting episode. We performed spectral analysis down to 4 ms time-scales, to characterize the ... More
NuSTAR Observations of GRB130427A establish a single component synchrotron afterglow origin for the late optical to multi-GeV emissionNov 20 2013GRB 130427A occurred in a relatively nearby galaxy; its prompt emission had the largest GRB fluence ever recorded. The afterglow of GRB 130427A was bright enough for the Nuclear Spectroscopic Telescope ARray (NuSTAR) to observe it in the 3-79 keV energy ... More
The Five Year Fermi/GBM Magnetar Burst CatalogMar 13 2015Apr 13 2015Since launch in 2008, the Fermi Gamma-ray Burst Monitor (GBM) has detected many hundreds of bursts from magnetar sources. While the vast majority of these bursts have been attributed to several known magnetars, there is also a small sample of magnetar-like ... More
The Third Catalog of Active Galactic Nuclei Detected by the Fermi Large Area TelescopeJan 24 2015Aug 26 2015The third catalog of active galactic nuclei (AGNs) detected by the Fermi-LAT (3LAC) is presented. It is based on the third Fermi-LAT catalog (3FGL) of sources detected between 100 MeV and 300 GeV with a Test Statistic (TS) greater than 25, between 2008 ... More
Very High Energy Observations of PSR B1951+32Jun 15 1997PSR B1951+32 is a gamma-ray pulsar detected by the Energetic Gamma Ray Experiment Telescope (EGRET) and identified with the 39.5 ms radio pulsar in the supernova remnant CTB 80. The EGRET data shows no evidence for a spectral turnover. Here we report ... More
A significant hardening and rising shape detected in the MeV/GeV nuFnu spectrum from the recently-discovered very-high-energy blazar S4 0954+65 during the bright optical flare in 2015 FebruaryApr 19 2016We report on Fermi Large Area Telescope (LAT) and multi-wavelength results on the recently-discovered very-high-energy (VHE, $E>$ 100 GeV) blazar S4 0954+65 ($z=0.368$) during an exceptionally bright optical flare in 2015 February. During the time period ... More
Fermi GBM Observations of GRB 150101B: A Second Nearby Event with a Short Hard Spike and a Soft TailJul 08 2018Aug 06 2018In light of the joint multimessenger detection of a binary neutron star merger as the gamma-ray burst GRB 170817A and in gravitational waves as GW170817, we reanalyze the Fermi Gamma-ray Burst Monitor data of one of the closest short gamma-ray bursts: ... More
Multiwavelength Observations of a Flare from Markarian 501Jul 16 1997We present multiwavelength observations of the BL Lacertae object Markarian 501 (Mrk 501) in 1997 between April 8 and April 19. Evidence of correlated variability is seen in very high energy (VHE, E > 350 GeV) gamma-ray observations taken with the Whipple ... More
Burst and Persistent Emission Properties during the Recent Active Episode of the Anomalous X-ray Pulsar 1E 1841-045Sep 05 2011Swift/BAT detected the first burst from 1E 1841-045 in May 2010 with intermittent burst activity recorded through at least July 2011. Here we present Swift and Fermi/GBM observations of this burst activity and search for correlated changes to the persistent ... More
First Results from a Search for TeV Emission from BL LacsJun 13 1997Two active galactic nuclei have been detected at TeV energies using the atmospheric Cherenkov imaging technique. The Whipple Observatory gamma-ray telescope has been used to observe all the BL Lacertae objects in the northern hemisphere out to a redshift ... More
Search for TeV Counterparts in Gamma-Ray BurstsJun 13 1997Based on BACODINE network notification the Whipple Observatory gamma-ray telescope has been used to search for the delayed TeV counterpart to BATSE-detected gamma-ray bursts. In the fast slew mode, any point in the sky can be reached within two minutes ... More
A Search for TeV Emission from Unidentified Sources in the Galactic PlaneJun 17 1997The ~70 unidentified sources of the EGRET sky survey may be one of its most important legacies. The identification of these sources at other wavelengths is critical to understanding their nature. Many have flat spectra out to 10 GeV which, if extrapolated ... More
TeV Observations of the Variability and Spectrum of Markarian 501Jun 15 1997Markarian 501 is only the second extragalactic source to be detected with high statistical certainty at TeV energies; it is similar in many ways to Markarian 421. The Whipple Observatory gamma-ray telescope has been used to observe the AGN Markarian 501 ... More
Constraints on Cosmic-Ray Origin Theories from TeV Gamma-Ray ObservationsJun 13 1997If supernova remnants (SNRs) are the sites of cosmic-ray acceleration, the associated nuclear interactions should result in observable fluxes of TeV gamma-rays from the nearest SNRs. Measurements of the gamma-ray flux from six nearby, radio-bright, SNRs ... More
Spectrum of TeV Gamma-Rays from the Crab NebulaJun 15 1997The Crab Nebula has become established as the standard candle for TeV gamma-ray astronomy using the atmospheric Cherenkov technique. No evidence for variability has been seen. The spectrum of gamma rays from the Crab Nebula has been measured in the energy ... More
Spectrum and Morphology of the Two Brightest Milagro Sources in the Cygnus Region: MGRO J2019+37 and MGRO J2031+41Feb 04 2012The Cygnus region is a very bright and complex portion of the TeV sky, host to unidentified sources and a diffuse excess with respect to conventional cosmic-ray propagation models. Two of the brightest TeV sources, MGRO J2019+37 and MGRO J2031+41, are ... More
A search for correlations of TeV gamma-rays with ultra-high energy cosmic raysJun 12 1997A search was conducted for TeV gamma-rays emitted from the direction of the ultra-high energy cosmic ray detected by the Fly's Eye Experiment with E ~ 3 x 10**20 eV. No enhancement was found at a level of 10**-10 gamma/cm**2-sec for E>350 GeV. This upper ... More
Section on Extragalactic Science Topics of the White Paper on the Status and Future of Ground-Based TeV Gamma-Ray AstronomyDec 03 2008This is a report on the findings of the extragalactic science working group for the white paper on the status and future of TeV gamma-ray astronomy. The white paper was commissioned by the American Physical Society, and the full white paper can be found ... More
Discovery and redshift of an optical afterglow in 71 square degrees: iPTF13bxl and GRB 130702AJul 22 2013Oct 08 2013We report the discovery of the optical afterglow of the gamma-ray burst (GRB) 130702A, identified upon searching 71 square degrees surrounding the Fermi Gamma-ray Burst Monitor (GBM) localization. Discovered and characterized by the intermediate Palomar ... More
Gamma Rays and Gravitational WavesMar 11 2019The first multimessenger observation of a neutron star merger was independently detected in gamma-rays by Fermi-GBM and INTEGRAL SPI-ACS and gravitational waves by Advanced LIGO and Advanced Virgo. Gravitational waves are emitted from systems with accelerating ... More
Milagro Observations of Multi-TeV Emission from Galactic Sources in the Fermi Bright Source ListApr 06 2009Aug 27 2009We present the result of a search of the Milagro sky map for spatial correlations with sources from a subset of the recent Fermi Bright Source List (BSL). The BSL consists of the 205 most significant sources detected above 100 MeV by the Fermi Large Area ... More
VAMOS: a Pathfinder for the HAWC Gamma-Ray ObservatoryAug 15 2014VAMOS was a prototype detector built in 2011 at an altitude of 4100m a.s.l. in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower ... More
Milagro Constraints on Very High Energy Emission from Short Duration Gamma-Ray BurstsMay 10 2007Recent rapid localizations of short, hard gamma-ray bursts (GRBs) by the Swift and HETE satellites have led to the observation of the first afterglows and the measurement of the first redshifts from this type of burst. Detection of >100 GeV counterparts ... More
Binary Millisecond Pulsar Discovery via Gamma-Ray PulsationsNov 06 2012Nov 26 2012Millisecond pulsars, old neutron stars spun-up by accreting matter from a companion star, can reach high rotation rates of hundreds of revolutions per second. Until now, all such "recycled" rotation-powered pulsars have been detected by their spin-modulated ... More
An Ordinary Short Gamma-Ray Burst with Extraordinary Implications: Fermi-GBM Detection of GRB 170817AOct 16 2017On August 17, 2017 at 12:41:06 UTC the Fermi Gamma-ray Burst Monitor (GBM) detected and triggered on the short gamma-ray burst GRB 170817A. Approximately 1.7 s prior to this GRB, the Laser Interferometer Gravitational-Wave Observatory (LIGO) triggered ... More
Tunable negative permeability in a quantum plasmonic metamaterialJan 21 2014We consider the integration of quantum emitters into a negative permeability metamaterial design in order to introduce tunability as well as nonlinear behavior. The unit cell of our metamaterial is a ring of metamolecules, each consisting of a metal nanoparticle ... More
On the interpretation of the Fermi GBM transient observed in coincidence with LIGO Gravitational Wave Event GW150914Jan 08 2018The weak transient detected by the Fermi Gamma-ray Burst Monitor (GBM) 0.4 s after GW150914 has generated much speculation regarding its possible association with the black-hole binary merger. Investigation of the GBM data by Connaughton et al. (2016) ... More
Fermi/GBM Observations of SGR J0501+4516 BurstsJul 11 2011We present our temporal and spectral analyses of 29 bursts from SGR J0501+4516, detected with the Gamma-ray Burst Monitor onboard the Fermi Gamma-ray Space Telescope during the 13 days of the source activation in 2008 (August 22 to September 3). We find ... More
Discovery of >350 GeV Gamma Rays from the BL Lacertae Object 1ES 2344+514Dec 24 1997We present the discovery of >350 GeV gamma-ray emission from the BL Lacertae object 1ES 2344+514 with the Whipple Observatory 10m gamma-ray telescope. This is the third BL Lac object detected at gamma-ray energies above 300 Gev, the other two being Markarian ... More
Signatures of the $A^2$ term in ultrastrongly-coupled oscillatorsJul 28 2014Jul 01 2015We study a bosonic matter excitation coupled to a single-mode cavity field via electric dipole. Counter-rotating and $A^2$ terms are included in the interaction model, ${\mathbf A}$ being the vector potential of the cavity field. In the ultrastrong coupling ... More
Coincidence of a high-fluence blazar outburst with a PeV-energy neutrino eventFeb 05 2016Mar 03 2016The discovery of extraterrestrial very-high-energy neutrinos by the IceCube collaboration has launched a quest for the identification of their astrophysical sources. Gamma-ray blazars have been predicted to yield a cumulative neutrino signal exceeding ... More
Tev Blazars: Status of ObservationsDec 01 1998The close relation between ground-based TeV observations and satellite borne $\gamma$-ray measurements has been important for the understanding of blazars. The observations which involve the TeV component in blazar studies are reviewed.
Milagro Observations of Potential TeV EmittersMar 02 2014This paper reports the results from three targeted searches of Milagro TeV sky maps: two extragalactic point source lists and one pulsar source list. The first extragalactic candidate list consists of 709 candidates selected from the Fermi-LAT 2FGL catalog. ... More
Instrumented Water Tanks can Improve Air Shower Detector SensitivityJul 15 1999Previous works have shown that water Cherenkov detectors have superior sensitivity to those of scintillation counters as applied to detecting extensive air showers (EAS). This is in large part due to their much higher sensitivity to EAS photons which ... More
Observation and Spectral Measurements of the Crab Nebula with MilagroOct 03 2011The Crab Nebula was detected with the Milagro experiment at a statistical significance of 17 standard deviations over the lifetime of the experiment. The experiment was sensitive to approximately 100 GeV - 100 TeV gamma ray air showers by observing the ... More
Search for a TeV Component of GRBs using the Milagrito DetectorJun 24 1999Observing gamma ray bursts (GRBs) in the TeV energy range can be extremely valuable in providing insight to GRB radiation mechanisms and in constraining source distances. The Milagrito detector was an air shower array which used the water Cherenkov technique ... More
The Large Scale Cosmic-Ray Anisotropy as Observed with MilagroJun 13 2008Apr 20 2009Results are presented of a harmonic analysis of the large scale cosmic-ray anisotropy as observed by the Milagro observatory. We show a two-dimensional display of the sidereal anisotropy pro jections in right ascension generated by the fitting of three ... More
Evidence for TeV Emission from GRB 970417aJan 07 2000Milagrito, a detector sensitive to very high energy gamma rays, monitored the northern sky from February 1997 through May 1998. With a large field of view and a high duty cycle, this instrument was well suited to perform a search for TeV gamma-ray bursts ... More
Calibration of the Milagro Cosmic Ray TelescopeJun 25 1999The Milagro detector is an air shower array which uses the water Cherenkov technique and is capable of continuously monitoring the sky at energies near 1 TeV. The detector consists of 20000 metric tons of pure water instrumented with 723 photo-multiplier ... More
Milagrito Detection of TeV Emission from Mrk 501Jun 24 1999The Milagro water Cherenkov detector near Los Alamos, New Mexico, has been operated as a sky monitor at energies of a few TeV between February 1997 and April 1998. Serving as a test run for the full Milagro detector, Milagrito has taken data during the ... More
An All-Sky Search for Steady VHE Gamma-Ray SourcesJun 23 1999The Milagrito water Cherenkov detector in the Jemez Mountains near Los Alamos, New Mexico took data from February 1997 to April 1998. Milagrito served as a prototype for the larger Milagro detector, which has just begun operations. Milagrito was the first ... More
The e-ASTROGAM gamma-ray space missionAug 12 2016The e-ASTROGAM is a gamma-ray space mission to be proposed as the M5 Medium-size mission of the European Space Agency. It is dedicated to the observation of the Universe with unprecedented sensitivity in the energy range 0.2 - 100 MeV, extending up to ... More
The Study of TeV Variability and Duty Cycle of Mrk 421 from 3 Years of Observations with the Milagro ObservatoryJan 09 2014TeV flaring activity with time scales as short as tens of minutes and an orphan TeV flare have been observed from the blazar Markarian 421 (Mrk 421). The TeV emission from Mrk 421 is believed to be produced by leptonic synchrotron self-Compton (SSC) emission. ... More
Search for Short Duration Bursts of TeV Gamma Rays with the Milagrito TelescopeJun 24 1999The Milagrito water Cherenkov telescope operated for over a year. The most probable gamma-ray energy was ~1 TeV and the trigger rate was as high as 400 Hz. We have developed an efficient technique for searching the entire sky for short duration bursts ... More
Status of the Milagro Gamma Ray ObservatoryJun 24 1999The Milagro Gamma Ray Observatory is the world's first large-area water Cherenkov detector capable of continuously monitoring the sky at TeV energies. Located in northern New Mexico, Milagro will perform an all sky survey of the Northern Hemisphere at ... More
TeV Gamma-Ray Sources from a Survey of the Galactic Plane with MilagroMay 04 2007A survey of Galactic gamma-ray sources at a median energy of ~20 TeV has been performed using the Milagro Gamma Ray Observatory. Eight candidate sources of TeV emission are detected with pre-trials significance $>4.5\sigma$ in the region of Galactic longitude ... More
Detection of 6 November 1997 Ground Level Event by MilagritoJun 24 1999Solar Energetic Particles from the 6 November 1997 solar flare/CME(coronal mass ejection) with energies exceeding 10 GeV have been detected by Milagrito, a prototype of the Milagro Gamma Ray Observatory. While particle acceleration beyond 1 GeV at the ... More
Study of the Shadows of the Moon and the Sun with VHE Cosmic RaysJun 24 1999Milagrito, a prototype for the Milagro detector, operated for 15 months in 1997-8 and collected 8.9 billion events. It was the first extensive air shower (EAS) array sensitive to showers intiated by primaries with energy below 1 TeV. The shadows of the ... More
A Measurement of the Spatial Distribution of Diffuse TeV Gamma Ray Emission from the Galactic Plane with MilagroMay 05 2008Aug 19 2008Diffuse $\gamma$-ray emission produced by the interaction of cosmic-ray particles with matter and radiation in the Galaxy can be used to probe the distribution of cosmic rays and their sources in different regions of the Galaxy. With its large field of ... More
First Results of a Study of TeV Emission from GRBs in MilagritoOct 29 1999Milagrito, a detector sensitive to gamma-rays at TeV energies, monitored the northern sky during the period February 1997 through May 1998. With a large field of view and high duty cycle, this instrument was used to perform a search for TeV counterparts ... More
Discovery of TeV Gamma-Ray Emission from the Cygnus Region of the GalaxyNov 21 2006The diffuse gamma radiation arising from the interaction of cosmic ray particles with matter and radiation in the Galaxy is one of the few probes available to study the origin of the cosmic rays. Milagro is a water Cherenkov detector that continuously ... More
The high-energy gamma-ray fluence and energy spectrum of GRB 970417a from observations with MilagritoJul 06 2002Evidence of TeV emission from GRB970417a has been previously reported using data from the Milagrito detector. Constraints on the TeV fluence and the energy spectrum are now derived using additional data from a scaler system that recorded the rate of signals ... More
Discovery of Localized Regions of Excess 10-TeV Cosmic RaysJan 24 2008Oct 14 2008An analysis of 7 years of Milagro data performed on a 10-degree angular scale has found two localized regions of excess of unknown origin with greater than 12 sigma significance. Both regions are inconsistent with gamma-ray emission with high confidence. ... More
Limits on Very High Energy Emission from Gamma-Ray Bursts with the Milagro ObservatoryNov 17 2003Feb 06 2004The Milagro telescope monitors the northern sky for 100 GeV to 100 TeV transient emission through continuous very high energy wide-field observations. The large effective area and ~100 GeV energy threshold of Milagro allow it to detect very high energy ... More
Constraints on Very High Energy gamma-ray emission from Gamma-Ray BurstsMar 11 2005The Milagro gamma-ray observatory employs a water Cherenkov detector to observe extensive air showers produced by high energy particles interacting in the Earth's atmosphere. Milagro has a wide field of view and high duty cycle, monitoring the northern ... More
Discovery of a new Soft Gamma Repeater: SGR J0418+5729Nov 30 2009Jan 19 2010On 2009 June 5, the Gamma-ray Burst Monitor (GBM) onboard the Fermi Gamma-ray Space Telescope triggered on two short, and relatively dim bursts with spectral properties similar to Soft Gamma Repeater (SGR) bursts. Independent localizations of the bursts ... More
Fermi GBM Observations of LIGO Gravitational Wave event GW150914Feb 11 2016Jun 01 2016With an instantaneous view of 70% of the sky, the Fermi Gamma-ray Burst Monitor (GBM) is an excellent partner in the search for electromagnetic counterparts to gravitational wave (GW) events. GBM observations at the time of the Laser Interferometer Gravitational-wave ... More
SGR J1550-5418 bursts detected with the Fermi Gamma-ray Burst Monitor during its most prolific activityFeb 14 2012Feb 28 2012We have performed detailed temporal and time-integrated spectral analysis of 286 bursts from SGR J1550-5418 detected with the Fermi Gamma-ray Burst Monitor (GBM) in January 2009, resulting in the largest uniform sample of temporal and spectral properties ... More
Prospects for GRB Science with the Fermi Large Area TelescopeJun 04 2009The LAT instrument on the Fermi mission will reveal the rich spectral and temporal gamma-ray burst phenomena in the > 100 MeV band. The synergy with Fermi's GBM detectors will link these observations to those in the well explored 10-1000 keV range; the ... More
Observation of Small-scale Anisotropy in the Arrival Direction Distribution of TeV Cosmic Rays with HAWCAug 20 2014Oct 10 2014The High-Altitude Water Cherenkov (HAWC) Observatory is sensitive to gamma rays and charged cosmic rays at TeV energies. The detector is still under construction, but data acquisition with the partially deployed detector started in 2013. An analysis of ... More
The e-ASTROGAM mission (exploring the extreme Universe with gamma rays in the MeV-GeV range)Nov 07 2016Nov 30 2016e-ASTROGAM (`enhanced ASTROGAM') is a breakthrough Observatory mission dedicated to the study of the non-thermal Universe in the photon energy range from 0.3 MeV to 3 GeV. The mission is based on an advanced space-proven detector technology, with unprecedented ... More
The e-ASTROGAM mission (exploring the extreme Universe with gamma rays in the MeV-GeV range)Nov 07 2016Jun 04 2017e-ASTROGAM (`enhanced ASTROGAM') is a breakthrough Observatory mission dedicated to the study of the non-thermal Universe in the photon energy range from 0.3 MeV to 3 GeV. The mission is based on an advanced space-proven detector technology, with unprecedented ... More
Constraints on Very High Energy Emission from GRB 130427AOct 20 2014Prompt emission from the very fluent and nearby (z=0.34) gamma-ray burst GRB 130427A was detected by several orbiting telescopes and by ground-based, wide-field-of-view optical transient monitors. Apart from the intensity and proximity of this GRB, it ... More
Search for Early Gamma-ray Production in Supernovae Located in a Dense Circumstellar Medium with the Fermi LATJun 04 2015Jun 26 2015Supernovae (SNe) exploding in a dense circumstellar medium (CSM) are hypothesized to accelerate cosmic rays in collisionless shocks and emit GeV gamma rays and TeV neutrinos on a time scale of several months. We perform the first systematic search for ... More
Observation of Markarian 421 in TeV gamma rays over a 14-year time spanOct 30 2013The variability of the blazar Markarian 421 in TeV gamma rays over a 14-year time period has been explored with the Whipple 10 m telescope. It is shown that the dynamic range of its flux variations is large and similar to that in X-rays. A correlation ... More
The Spectral Energy Distribution of Fermi bright blazarsDec 10 2009(Abridged) We have conducted a detailed investigation of the broad-band spectral properties of the \gamma-ray selected blazars of the Fermi LAT Bright AGN Sample (LBAS). By combining our accurately estimated Fermi gamma-ray spectra with Swift, radio, ... More
The e-ASTROGAM mission (exploring the extreme Universe in the MeV-GeV range)Nov 07 2016e-ASTROGAM (`enhanced ASTROGAM') is a breakthrough Observatory mission dedicated to the study of the non-thermal Universe in the photon energy range from 0.3 MeV to 3 GeV. The mission is based on an advanced space-proven detector technology, with unprecedented ... More
The e-ASTROGAM mission (exploring the extreme Universe in the MeV-GeV range)Nov 07 2016Nov 08 2016e-ASTROGAM (`enhanced ASTROGAM') is a breakthrough Observatory mission dedicated to the study of the non-thermal Universe in the photon energy range from 0.3 MeV to 3 GeV. The mission is based on an advanced space-proven detector technology, with unprecedented ... More
BurstCube: A CubeSat for Gravitational Wave CounterpartsAug 28 2017BurstCube will detect long GRBs, attributed to the collapse of massive stars, short GRBs (sGRBs), resulting from binary neutron star mergers, as well as other gamma-ray transients in the energy range 10-1000 keV. sGRBs are of particular interest because ... More