The High Altitude Water Cherenkov Gamma-Ray Observatory has been accumulating a progressively deeper exposure of the TeV sky since its inauguration in March 2015. Located at geographical latitude $+19^\circ$N, HAWC has been able to perform a deep and unbiased survey of two thirds of the sky. We analyzed three years of HAWC data searching for long term persistent emission from a redshift limited ($z\leq 0.3$) sample of active galactic nuclei drawn from the {\it Fermi}-LAT 3FHL catalog. The HAWC dataset confirms the high significance detection of the two nearest BL Lac objects, \mbox{Mrk 421} and \mbox{Mrk 501}, and sets limits for the rest of the sample, down to integrated photon fluxes of order $N(>0.5~{\rm TeV})\lesssim 10^{-12}\,\rm cm^{-2}s^{-1}$. We present and discuss some of the results of this survey, focusing on individual objects of particular interest.
The High Altitude Water Cherenkov Observatory (HAWC) is an air shower array currently under construction in Mexico at an altitude of 4100 m. HAWC will consist of 300 large water tanks covering an area of about 22000 square meters and instrumented with 4 photomultipliers each. The experimental design allows for highly efficient detection of photon-induced air showers in the TeV and sub-TeV range and gamma-hadron separation. We show that HAWC has a reasonable chance to observe the high-energy power law components of GRBs that extend to 50 GeV. In particular, HAWC will be capable of observing eve…
Galactic diffuse TeV gamma-ray emission is produced by the interaction of high-energy cosmic-ray particles with matter and radiation in our Galaxy. The measurement of Galactic diffuse TeV gamma-ray emission would provide strong constraints on the acceleration and propagation of Galactic cosmic rays. The High Altitude Water Cherenkov (HAWC) Observatory, located in central Mexico at 4100 m above sea level, is sensitive to gamma rays between a few hundreds GeV and about 100 TeV. Thanks to its large field of view of 2 steradians and excellent background estimation, HAWC has a unique capability to …
The HAWC gamma-ray observatory is a wide field of view and high duty cycle $γ$-ray detector investigating the 0.1 - 100 TeV energy range. It has detected supermassive black holes in the near Universe, and is seeking to detect black hole related objects like gamma-ray bursts, Galactic binary systems, primordial black holes and gravitational wave mergers. Daily light curves of the BL Lac objects Mrk 421 and Mrk 501 are presented here, together with a compilation of studies of black hole related objects.
The cosmic-ray flux in the Galaxy can be characterized by combining the knowledge of the distribution of gas in the Galaxy and the observation of gamma rays. We analyze the data from the HAWC Observatory to look for gamma rays in three galactic giant molecular clouds, that are outside the galactic plane ($|b|>5^{\circ}$). We can then test the paradigm that the measured local cosmic-ray flux is the same as the "sea" of Galactic cosmic rays. Due to its large field of view, and high duty cycle, HAWC is suitable to search for gamma rays from large structures in the TeV gamma-ray regime. We present…
The dynamics of dwarf irregular (dIrr) galaxies are observed to be dominated by dark matter (DM). Recently, the DM density distribution has been studied for 31 dIrrs. Their extended DM halo (Burket type profile) makes these objects good candidates for DM searches. Located in Puebla (Mexico), the High Altitude Water Cherenkov (HAWC) Observatory is an optimal in- strument to perform such DM searches, because of its large sky coverage (8.4 sr per day). We analyzed a set of two years of HAWC data and we found no significant DM signal from dIrr galaxies. We present the upper limits for DM annihilat…
M87 is a giant radio galaxy located in the Virgo Cluster, known to be a very high energy (VHE) gamma-ray source. As radio galaxies are considered the misaligned low-redshift counterparts of blazars, they are excellent laboratories for testing AGN emission models. M87 has been detected and monitored by Fermi-LAT and several atmospheric Cherenkov telescopes. Recently, the HAWC Collaboration presented marginal evidence of 4.5 year TeV gamma-ray emission from this object. The HAWC data has the potential to constrain the average VHE emission of sources of complex behavior, like M87, for which the p…
The particle lateral distribution function (LDF) of air showers at a given altitude is sensitive to the mass composition and primary energy of cosmic rays. Studies of the LDF are difficult to perform due to experimental effects such as sampling bias, as well as shower-to-shower fluctuations in particle density. The High Altitude Water Cherenkov (HAWC) observatory, a dense air shower array located in central Mexico at 4100 m a.s.l., is well-suited to perform detailed event-by-event studies of the LDF of multi-TeV cosmic-ray showers. The detector is instrumented with 1,200 photomultipliers (PMTs…
Cosmic rays in the inner solar system are subject to deflection by both the geomagnetic and interplanetary magnetic fields, and simultaneously interact with the Sun's photosphere resulting in the production of gamma rays. This phenomenon can be studied by observing the deficit ("shadow") in the cosmic ray flux from the direction of the Sun and searching for an excess photon signal above the isotropic background. The High Altitude Water Cherenkov (HAWC) Observatory in Mexico has been taking data on the solar disk at TeV energies since the end of 2014. We present our first efforts to estimate th…
Geminga is a radio-quiet pulsar ~250 parsecs from Earth that was first discovered as a GeV gamma-ray source and then identified as a pulsar. Milagro observed an extended TeV source spatially consistent with Geminga. HAWC observes a similarly extended source. Observations of Geminga's flux and extension will be presented.
The High Altitude Water Cherenkov Observatory (HAWC) has a wide field-of-view (FOV, $\sim$2sr) and a high duty cycle ($\sim$95\%), which make it a powerful survey and monitoring experiment for sources of TeV gamma rays. We present a systematic survey of gamma-ray sources based on the Fermi 3FHL catalog. Sources are restricted to HAWC's FOV (Declination 19$^\circ$ $\pm$ 40$^\circ$) and to extragalactic sources with redshift: 0.001 $<$ z $<$ 0.3. Extragalactic gamma-ray sources are dominated by active galactic nuclei (AGN) and TeV gamma-ray sources are mostly BL Lac-type blazars. The study of AG…
The Diffuse Gamma-Ray Background (DGB) above 100 GeV at high-latitudes is expected to be produced by unresolved extragalactic objects such as active galactic nuclei, isotropic Galactic gamma-rays, and possible emission from dark matter annihilations or decays in the Galactic dark matter halo. The DGB has been observed up to nearly 1 TeV, but has yet to be detected at higher energies. Detections or stringent limits on the DGB above this energy would have strong multimessenger consequences, such as constraining the origin of astrophysical neutrinos observed in IceCube. The High Altitude Water Ch…
The High Altitude Water Cherenkov (HAWC) observatory is a large field of view, continuously operated, TeV gamma-ray experiment under construction at 4,100 m a.s.l. in Mexico. The HAWC observatory will have an order of magnitude better sensitivity, angular resolution, and background rejection than its predecessor, the Milagro experiment. The improved performance will allow us to detect both transient and steady emissions, to study the Galactic diffuse emission at TeV energies, and to measure or constrain the TeV spectra of GeV gamma-ray sources. In addition, HAWC will be the only ground-based i…
The HAWC gamma ray observatory is located at the Sierra Negra Volcano in Puebla, Mexico, at an altitude of 4,100 meters. HAWC is a wide field of view array of 300 water Cherenkov detectors that are continuously surveying ~ 2sr of the sky, operating since March 2015. The large collected data sample allows HAWC to perform an unbiased monitoring of the BL Lac Mrk 421. This is the closest and brightest known extragalactic high-synchrotron-peaked BL Lac in the gamma-ray/X- ray bands and is extensively monitored by the Large Area Telescope (LAT) on-board the Fermi satellite, and the BAT and XRT inst…
The High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory surveys the very high energy sky in the $\sim300$ to 100 TeV energy range and has detected two high-synchrotron-peaked BL Lacertae objects, Markarian 421 and Markarian 501 in a period of time of 837 days between June 2015 and December 2017. In this work, we present the detailed time-average spectral analysis. Using an extragalactic background light model, we address the difference in the intrinsic spectral properties between the two blazars above 1 TeV, preliminary results show that the intrinsic spectrum of Mrk 421 is better descr…
The HAWC Gamma-Ray Observatory has reported the discovery of TeV gamma-ray emission extending several degrees around the positions of Geminga and B0656+14 pulsars. Assuming these gamma rays are produced by inverse Compton scattering off low-energy photons in electron halos around the pulsars, we determine the diffusion of electrons and positrons in the local interstellar medium. We will present the morphological and spectral studies of these two VHE gamma-ray sources and the derived positron spectrum at Earth.
The Milky Way contains hundreds of binary systems which are known to emit in radio and X-rays, but only a handful of binaries have been observed to produce very high-energy gamma rays. In addition, the emission mechanisms which produce the gamma rays in the few known sources are not well understood. To improve the statistics of binary sources in the TeV band, the High-Altitude Water Cherenkov Gamma-ray Observatory, or HAWC, has begun to carry out a simultaneous survey of TeV binary candidates in the Northern Hemisphere between 100 GeV and 100 TeV. HAWC is a surface array that records air showe…
We present a search in IceCube data for neutrino emission from Galactic TeV gamma-ray sources detected by the HAWC gamma-ray observatory. HAWC serves as the excellent instrument to complement IceCube with its energy range extending to very high energies. Assuming that the highest energy photons originate from the decay of pions, rather than from accelerated leptons, the very high energy gamma-rays observed by HAWC are expected to be correlated with neutrinos. Using eight years of IceCube data, we report on two analyses that investigate a possible neutrino--gamma ray correlation. The first is a…
Detections of very-high-energy (VHE; > 100 GeV) photons from Gamma-ray bursts (GRBs) can provide fundamental information on the involved radiative processes, physical composition of the ejecta and acceleration processes. The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is the best gamma-ray instrument to study transient phenomena over a long period of time from 100 GeV to 100 TeV. Its large field of view and duty cycle (> 95%) allow it to search blindly for sources of GRBs and to follow up on external alerts from satellite instruments, such as Fermi and Swift, searching for their…
The High Altitude Water Cherenkov (HAWC) Observatory is a TeV gamma-ray detector, completed in early 2015. HAWC started science operations in August 2013 with a third of the detector taking data. Several known gamma-ray sources have already been detected with the first HAWC data. Among these sources, the Crab Nebula, the brightest steady gamma-ray source at very high energies in our Galaxy, has been detected with high significance. In this contribution I will present the results of the observations of the Crab Nebula with HAWC, including time variability, and the detector performance based on …
We present the first catalogs of the highest-energy (above 56 TeV and 100 TeV) gamma-ray sources seen by the High Altitude Water Cherenkov (HAWC) Observatory. The wide field-of-view of HAWC naturally lends itself to unbiased all-sky surveys and newly developed event-by-event gamma-ray energy reconstruction algorithms have allowed unprecedented energy resolution. The sources presented here are the highest-energy sources ever detected. All are coincident with known lower-energy gamma-ray sources within our Galaxy. These objects may have implications for the sources of Galactic cosmic rays; since…
The High-Altitude Water Cherenkov Observatory (HAWC) is a large field of view (~2 sr) continuously operating experiment sensitive to very-high energy (VHE) gamma rays (~0.3-100 TeV). These characteristics make it well suited for observing or constraining the VHE emission of rapid transients such as some gravitational waves progenitors. Of special interest are the events at low redshift where the attenuation due to the extragalactic background light is minimal. This is the case for binary neutron star mergers in the horizon of the LIGO and Virgo experiments, for which HAWC can either detect or …
Astrophysical scenarios provide a unique opportunity to test the possible signatures of Lorentz Invariance Violation (LIV) due to the high energies and the very long distances they involve. An isotropic correction to the photon dispersion relation, by hypothetical Lorentz invariance violation, has a consequence that photons of sufficient energy are unstable and decay very fast. The High Altitude Water Cherenkov (HAWC) observatory is sensitive to gamma-rays in the 100 GeV to 100 TeV energy range, making it a very useful tool to study LIV. In this work we present potential stringent limits for t…
Nearby electron/positron accelerators, mostly Pulsar Wind Nebulae (PWNe), have been proposed as potential origins of the positron excess above 10 GeV. The HAWC Observatory reveals two very extended sources spatially coincident with two nearby middle-aged pulsars: Geminga and PSR B0656+14, suggesting ultrarelativistic electrons/positrons accelerated in our backyard. Morphological studies on these two PWNe provide a constraint on the diffusion coefficient at HAWC energies. In this poster, we will present the model development and morphological studies on these PWNe, and the derived diffusion coe…
The framework of relativistic quantum-field theories requires Lorentz Invariance. Many theories of quantum gravity, on the other hand, include violations of Lorentz Invariance at small scales and high energies. This generates a lot of interest in establishing limits on such effects, and, if possible, observing them directly. Gamma-ray observatories provide a tool to probe parts of the parameter space of models of Lorentz Invariance Violation that is not accessible in terrestrial laboratories and man-made accelerators. Transients, especially gamma-ray bursts, are a particularly promising class …
The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is carrying out a detailed survey of the northern sky at TeV energies. 2HWC J2006+341 is a newly discovered source reported by the point source search in the 2HWC HAWC Observatory Gamma Ray Catalog. Using $\sim$1038 days of HAWC data we carried out a detailed analysis of the region revealing extended emission. No emission has been detected by other TeV instruments at the location of 2HWC J2006+341. We also analyzed publicly available data from the \textit{Fermi}-LAT that show for the first time the existence of an extended GeV sour…
The High Altitude Water Cherenkov (HAWC) Observatory is a ground-based TeV gamma-ray observatory in the state of Puebla, Mexico at an altitude of 4100 m. Its 22,000 m$^2$ instrumented area, wide field of view ($\sim$2 sr), and >95% uptime make it an ideal instrument for discovering gamma-ray burst (GRB) emission at $\sim$100 GeV. Such a discovery would provide key information about the origins of prompt GRB emission as well as constraints on extra-galactic background light (EBL) models and the violation of Lorentz invariance. We will present prospects for discovering GRB emission at $\sim$100 …
The High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory was completed this year at a 4100-meter site on the flank of the Sierra Negra volcano in Mexico. HAWC is a water Cherenkov ground array with the capability to distinguish 100 GeV - 100 TeV gamma rays from the hadronic cosmic-ray background. HAWC is uniquely suited to study extremely high energy cosmic-ray sources, search for regions of extended gamma-ray emission, and to identify transient gamma-ray phenomena. HAWC will play a key role in triggering multi-wavelength and multi-messenger studies of active galaxies, gamma-ray bursts, …
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 mod…
Due to the high energies and long distances involved, astrophysical observations provide a unique opportunity to test possible signatures of Lorentz Invariance Violation (LIV). Superluminal LIV enables the decay of photons at high energy over relatively short distances, giving astrophysical spectra which have a hard cutoff above this energy. The High Altitude Water Cherenkov (HAWC) observatory is the most sensitive currently-operating gamma-ray observatory in the world above 10 TeV. Together with the recent development of an energy-reconstruction algorithm for HAWC using an artificial neural n…
The High-Altitude Water Cherenkov Observatory, or HAWC, is carrying out an unbiased survey of cosmic rays and gamma rays from the Northern Hemisphere between 100 GeV and 100 TeV. HAWC is currently the only high-uptime wide-field TeV observatory in operation, and has a robust program to search for flares and other transient sources of gamma rays. The detector is also well suited to observe spatially extended regions of gamma-ray emission and cosmic-ray anisotropy. HAWC recently concluded its first year of data taking with the complete detector. The results include not only observations of many …
The HAWC gamma ray observatory is located at the Sierra Negra Volcano in Puebla, Mexico, at an altitude of 4,100 meters. HAWC is a wide field of view array of 300 water Cherenkov detectors that are continuously surveying 2sr of the sky since March 2015. The large collected data sample consisting in more than 3 years makes HAWC an ideal instrument to perform an unbiased monitoring of blazars in the very-high-energy (VHE) emission. This is particular relevant for Mrk 421, one of the closest and brightest blazars in the gamma-ray/X-ray classified as highsynchrotron-peaked BL Lac class. In this wo…
The HAWC collaboration has recently completed the construction of a gamma-ray observatory at an altitude of 4100 meters on the slope of the Sierra Negra volcano in the state of Puebla, Mexico. In order to achieve an optimal angular resolution, energy reconstruction, and cosmic-ray background suppression for the air showers observed by HAWC, it is crucial to obtain good timing and charge calibrations of the photosensors in the detector. The HAWC calibration is based on a laser system which is able to deliver short light pulses to all the tanks in the array. The light intensity can range over 7 …
Data from 105 days from the High Altitude Water Cherenkov Observatory (HAWC) have been used to place a new limit on an isotropic diffuse gamma-ray population above 10 TeV. High- energy isotropic diffuse gamma-ray emission is produced by unresolved extragalactic objects such as active galactic nuclei, with potential contributions from interactions of high-energy cosmic rays with the inter-Galactic medium, or dark matter annihilation. Isotropic diffuse gamma-ray emission has been observed up to nearly 1 TeV. Above this energy, only upper limits have been reported. Observations or limits of the i…
The era of multimessenger astrophysics has arrived with the simultaneous operation of large cosmic-ray, gamma-ray, neutrino, and gravitational-wave observatories. In just the past two years, an electromagnetic (EM) counterpart was detected for a gravitational wave event, and evidence for an EM counterpart of high energy neutrinos has been identified. These measurements have had a major impact on our view of the non-thermal universe, but understanding cosmic accelerators require a substantial increase in the number of multimessenger observations. The Astrophysical Multimessenger Observatory Net…
Resolving the Galactic Center Region's Gamma-Ray Emission and Searching for its Neutrino Counterpart with HAWC and IceCube
Instituto de Física, Universidad Nacional Autónoma de México（墨西哥国立自治大学物理研究所）；Universidad de Costa Rica（哥斯达黎加大学）；Universidad Michoacana de San Nicolás de Hidalgo（米却肯圣尼古拉斯德伊达尔戈大学）；Department of Physics and Astronomy, Michigan State University（密歇根州立大学物理与天文学系）；Temple University（天普大学）；Instituto de Astronomía, Universidad Nacional Autónoma de México（墨西哥国立自治大学天文研究所）；Universidad Autónoma de Chiapas（恰帕斯自治大学）；Instituto Nacional de Astrofísica, Óptica y Electrónica（国家天体物理学、光学和电子研究所）；Institute of Nuclear Physics Polish Academy of Sciences（波兰科学院核物理研究所）
The High Altitude Water Cherenkov (HAWC) observatory monitors the gamma-ray sky at energies between 100 GeV and 100 TeV with a wide field of view of $\sim 2$ steradians. A duty cycle of $\sim 90$% allows HAWC to scan two thirds of the sky every day and has resulted in an unprecedented data set of unbiased and evenly sampled daily TeV light curves, collected over more than one year of operation since the completion of the array. These measurements highlight the flaring activity of the blazars Markarian 421 and Markarian 501 and allow us to discuss the frequency of high flux states and correlati…
High-mass microquasars (HMMQs) are powerful particle accelerators, but their mechanism of the high-energy emission is poorly understood. To date, only a handful of these particle engines have ever been observed to emit gamma-ray photons and are thus potential TeV gamma-ray emitters. In this work, we study four HMMQs, namely, LS 5039, Cyg X-1, Cyg X-3, and SS 433 using the data from the High Altitude Water Cherenkov (HAWC) observatory. We perform time dependent analyses on each HMMQ to look for any periodic variations in their flux. We produce light curves using the HAWC daily maps from which w…
A new ground-based wide-field extensive air shower array known as the High-Altitude Water Cherenkov (HAWC) Observatory promises a new window to monitoring the $\sim$100 GeV gamma-ray sky with the potential for detecting a high energy spectral cutoff in gamma-ray bursts (GRBs). It represents a roughly 15 times sensitivity gain over the previous generation of wide-field gamma-ray air shower instruments and is able to detect the Crab Nebula at high significance ($>$5 $σ$) with each daily transit. Its wide field-of-view ($\sim$2 sr) and $>$95% uptime make it an ideal instrument for detecting GRB e…
A number of Galactic sources emit GeV-TeV gamma rays that are produced through leptonic and/or hadronic mechanisms. Spectral analysis in this energy range is crucial in order to understand the emission mechanisms. The HAWC Gamma-Ray Observatory, with a large field of view and location at $19^\circ$ N latitude, is surveying the Galactic Plane from high Galactic longitudes down to near the Galactic Center. Data taken with partially-constructed HAWC array in 2013-2014 exhibit TeV gamma-ray emission along the Galactic Plane. A high-level analysis likelihood framework for HAWC, also presented at th…
We describe measurements of GeV and TeV cosmic rays with the High-Altitude Water Cherenkov Gamma-Ray Observatory, or HAWC. The measurements include the observation of the shadow of the moon; the observation of small-scale and large-scale angular clustering of the TeV cosmic rays; the prospects for measurement of transient solar events with HAWC; and the observation of Forbush decreases with the HAWC engineering array and HAWC-30.
The High-Altitude Water Cherenkov (HAWC) Observatory is a ground-based TeV gamma-ray observatory in the state of Puebla, Mexico at an altitude of 4100 m above sea level. Its $\sim$22,000 m$^2$ instrumented area, wide field of view (2 sr), and $>$95% uptime make it an ideal instrument for discovering gamma-ray burst (GRB) emission at $>$100 GeV. Such a discovery would provide key information about the origins of prompt GRB emission as well as constraints on EBL models and the violation of Lorentz invariance. We present here the results of our current GRB search methods, which include an all-sky…
The HAWC observatory recently published their second source catalog with 39 very high energy gamma-ray sources based on 507 days of exposure time. Among these, there were 16 sources that are more than one degree away from any known TeV source. We studied 13 of these 16 sources with VERITAS and \textit{Fermi}-LAT data. VERITAS, an array of four imaging atmospheric Cherenkov telescopes observing gamma rays with energies higher than 85 GeV, can provide a more detailed image of the source with much shorter exposure time and with better angular resolution. With \textit{Fermi}-LAT data, we searched …
The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field of view (1.8 Sr) and high duty cycle (>95% up-time) detector of unique capabilities for the study of TeV gamma-ray sources. Installed at an altitude of 4100m in the Northern slope of Volcán Sierra Negra, Puebla, by a collaboration of about thirty institutions of Mexico and the United States, HAWC has been in full operations since March 2015, surveying 2/3 of the sky every sidereal day, monitoring active galaxies and mapping sources in the Galactic Plane to a detection level of 1 Crab per day. This contribution summa…
The High Altitude Water Cherenkov (HAWC) Observatory is a wide-field-of-view gamma-ray observatory that is optimized to detect gamma rays between ~300 GeV and several hundred TeV. The HAWC Collaboration recently released their third source catalog (3HWC), which contains 65 sources. One of these sources, the ultra-high-energy gamma-ray source 3HWC J1908+063, may exhibit a hardening of the spectral index at the highest energies (above 56 TeV). At least two populations of particles are needed to satisfactorily explain the highest energy emission. This second component could be leptonic or hadroni…
The H.E.S.S. collaboration recently published its Galactic Plane Survey, which is a deep survey of half of the Milky Way in TeV gamma-rays, using almost 10 years of observations. It contains 78 sources, including 16 new sources. On the other hand, the HAWC collaboration also published its 2HWC catalogue based on 507 days of data. It is the result of the first source search performed with the complete HAWC detector, covering two thirds of the sky. In this search, 39 sources have been reported, amongst them 16 detected for the first time at TeV energies. The HAWC data set doubled since then, rev…
The HAWC gamma ray observatory, to be constructed at Sierra Negra, Puebla in Mexico, is a large array of water Cherenkov detectors sited at an elevation of 4100 m, which has been optimized for gamma/hadron discrimination of the primary cosmic rays in the TeV energy range. It is based on the Milagro experience, but the design has been changed from a water pond to individual water tanks. In order to validate the design with large water tanks a prototype array has been constructed near the HAWC site with 3 of the largest commercial rotomolded plastic tanks available in Mexico. They have been inst…
The High Altitude Water Cherenkov (HAWC) observatory is an air-shower array located in Mexico. It is sensitive to the highest energy photons we detect at the Earth, reaching energies of several tens of TeV. The observatory was completed more than one year ago and we are presenting in this contribution the first results about its performance. We also show the results of the first-year survey, the first flaring events detected by the observatory, its sensitivity to extended sources and the plans for the upgrade that is currently taking place.
The observation of Gamma Ray Bursts (GRBs) with very-high-energy (VHE) gamma rays can provide understanding of the particle acceleration mechanisms in GRBs, and can also be used to probe the extra-galactic background light and place constraints on Lorentz invariance violation. We present prospects for GRB detection by the ground-based HAWC (High Altitude Water Cherenkov) gamma-ray observatory. We model the VHE spectrum of GRBs by extrapolating observations by Fermi LAT and other observatories to higher energies. Under the assumption that only e-pair production associated with extra-galactic ba…
The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field-of-view observatory sensitive to 100 GeV - 100 TeV gamma rays and cosmic rays. The HAWC observatory is also sensitive to diverse indirect searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from non-luminous dark matter subhalos. Among the most promising classes of objects for the indirect detection of dark matter are dwarf spheroidal galaxies. These objects are expected to have few astro…
The High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory is designed to record air showers produced by cosmic rays and gamma rays between 100 GeV and 100 TeV. Because of its large field of view and high livetime, HAWC is well-suited to measure gamma rays from extended sources, diffuse emission, and transient sources. We describe the sensitivity of HAWC to emission from the extended Cygnus region as well as other types of galactic diffuse emission; searches for flares from gamma-ray bursts and active galactic nuclei; and the first measurement of the Crab Nebula with HAWC-30.
Supernova remnants (SNRs) have long been hypothesized as the main source of Galactic Cosmic Rays up to PeV energies. Some of them have indeed been shown to accelerate protons to TeV energies and above. But which of them are indeed efficient accelerators of protons and nuclei? And up to which energies can they accelerate these particles? Measurements of non-thermal emission, especially in the X-ray and gamma-ray regimes, are essential to answer these questions. The High-Altitude Water Cherenkov (HAWC) observatory, surveying the northern TeV gamma-ray sky, is currently the most sensitive wide fi…
The High-Altitude Water Cherenkov (HAWC) Observatory records the air showers produced by cosmic rays and gamma rays at a rate of about 20 kHz. While the events observed by HAWC are 99.9% hadronic cosmic rays, this background can be strongly suppressed using topological cuts that preferentially select electromagnetic air showers. Using this capability of HAWC, we can create a sample of air showers dominated by gamma rays and cosmic electrons and positrons. HAWC is one of the few operating observatories capable of measuring showers produced by electron and positron primaries above 1 TeV, and can…
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 experim…
