Markus Garczarczyk, Markus Gaug, Angelo Antonelli, Denis Bastieri, Josefa Becerra-Gonzalez, Stefano Covino, Antonio La Barbera, Alessandro Carosi, Nicola Galant… 展开作者
Markus Garczarczyk, Markus Gaug, Angelo Antonelli, Denis Bastieri, Josefa Becerra-Gonzalez, Stefano Covino, Antonio La Barbera, Alessandro Carosi, Nicola Galante, Francesco Longo, Valeria Scapin, Susanna Spiro
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Contribution to the 31st ICRC, Lodz, Poland, July 2009
MAGIC is currently the most suitable instrument to perform observations of the prompt an early afterglow emission from Gamma Ray Bursts (GRBs) at energies above 25 GeV. The instrument is designed to have the lowest possible energy threshold and fastest reaction time to GRB Coordinates Network (GCN) alerts. The MAGIC-I telescope started to follow-up GCN alerts in the beginning of 2005. Since then, more than 50 GRB candidates were observed. Just now MAGIC-II, the second telescope has started to operate. Both telescopes together will have a factor of three better sensitivity.
On January 2, the MAGIC-I Telescope observed GRB090102 (z=1.55) under particularly good observation conditions. Using the recently upgraded MAGIC-1 sum trigger system, upper limits down to below 50 GeV have been obtained. This is the first time that the new trigger system was fully exploited for a Gamma-ray Burst (GRB) observation and shows the capabilities of the MAGIC observatory for future follow-up observations.
Gamma-ray bursts are cosmological sources emitting radiation from the gamma-rays to the radio band. Substantial observational efforts have been devoted to the study of GRBs during the prompt phase, i.e. the initial burst of high-energy radiation, and during the longer-lasting afterglows. In spite of many successes in interpreting these phenomena there are still several open key questions about the fundamental emission processes, their energetics and the environment. Moreover, independently of their modeling, GRB spectra are remarkably simple, being satisfactorily fitted with power-laws, and th…
Gamma rays from extragalactic sources are attenuated by pair-production interactions with diffuse photons of the extragalactic background light (EBL). Gamma-ray bursts (GRBs) are a source of high-redshift photons above 10 GeV, and could be therefore useful as a probe of the evolving UV background radiation. In this paper, we develop a simple phenomenological model for the number and redshift distribution of gamma-ray bursts that can be seen at GeV energies with the Fermi satellite and MAGIC atmospheric Cherenkov telescope. We estimate the observed number of gamma rays per year, and show how th…
Gamma-Ray Bursts (GRBs) are one of the main targets for current and next generation Imaging Atmospheric Cherenkov Telescopes (IACTs). Given their transient behavior, especially in the case of their prompt emission phase, performing fast follow-up observations is challenging for IACTs, which have a narrow field of view and limited duty cycle. Despite this, MAGIC plays a major role in the search for Very High Energy (VHE, E>100 GeV) gamma-ray emission from GRBs: this is possible thanks to its fast repositioning speed, low energy threshold and high sensitivity at the lowest energies. In 2013 the …
In the last couple of years the Magic air Cherenkov telescope has made significant contributions to very high energy $γ$-ray astronomy. These include the detection of the galactic binary system LSI +61 303 and the observation of pulsed emission from the Crab pulsar. Extragalactic objects like the famous FSRQ 3C 279 and the LBL S5 0716+714 have both been detected during optical high states, and the radio galaxy M87 could be observed during an unexpected strong $γ$-ray outburst. Given its low energy trigger threshold (~50 GeV) and fast repositioning time of less than 30s the Magic air Cherenkov …
Hints for a GeV component in the emission from GRBs are known since the EGRET observations during the '90s and they have been recently confirmed by the data of the Fermi satellite. These results have, however, shown that a fully satisfactory interpretative framework of the GRB phenomena is still lacking. The MAGIC telescope opens the possibility to extend the measurement of GRBs in the several tens up to hundreds of GeV energy range. From the theoretical point of view, both leptonic and hadronic processes have been suggested to explain the possible GeV/TeV counterpart of GRBs. Observations wit…
Major Atmospheric Gamma Imaging Cherenkov Telescopes (MAGIC) detected the gamma-ray afterglow of GRB 190114C, which can constrain microscopic parameters of the shock-heated plasma emitting non-thermal emission. Focusing on the early afterglow of this event, we numerically simulate the spectrum and multi-wavelength light curves with constant and wind-like circumstellar medium using a time-dependent code. Our results show that the electron acceleration timescale at the highest energies is likely shorter than 20 times the gyroperiod to reproduce the GeV gamma-ray flux and its spectral index repor…
Very high energy gamma ray emission from the active galactic nucleus PG 1553+113 was observed during 2005 and 2006 by the MAGIC collaboration, for a total observation time of 18.8 hours. Here we present the results of follow up observations: more than 20 hours of good quality data collected by the MAGIC Telescope during the 2007 and 2008 campaigns. The obtained spectra are compared and combined with previous measurements, and corrected for absorption adopting different EBL models. Upper limits on the unknown source redshift are derived by assuming the absence of a break in the intrinsic spectr…
We present the first search for signatures of brane-world extra-dimensional dark matter (DM) in the very-high-energy gamma-ray band by scrutinizing observations of the dwarf spheroidal galaxy Segue 1 with the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescope system. Branons are new degrees of freedom that appear within flexible brane-world models: they are weakly interacting massive particles and natural DM candidates. The ground-based gamma-ray telescopes MAGIC could indirectly detect branon DM in the multi-TeV mass range by observing secondary products of DM annihilation into Stand…
The MAGIC observations of late sub-TeV photons from GRB190114C enable us, for the first time, to determine the details of the emission process in a GRB afterglow and to pin down the physical parameters, such as the bulk Lorentz factor and the Lorentz factor of the emitting electrons as well as some of the microphysical parameters. We find that the sub-TeV emission is an Inverse Compton radiation produced at the early afterglow stage. Combining the sub-TeV and X-ray observations we narrow uncertainties in the conditions inside the emitting zone, almost eliminating them for some parameters. Seve…
The TAROT telescopes (Telescopes a Action Rapide pour les Objets Transitoires) are two robotic observatories designed to observe the prompt optical emission counterpart and the early afterglow of gamma ray bursts (GRBs). We present data acquired between 2001 and 2008 and discuss the properties of the optical emission of GRBs, noting various interesting results. The optical emission observed during the prompt GRB phase is rarely very bright: we estimate that 5% to 20% of GRBs exhibit a bright optical flash (R<14) during the prompt gamma-ray emission, and that more than 50% of the GRBs have an o…
Blazars, a class of Active Galactic Nuclei (AGN) characterized by a close orientation of their relativistic outflows (jets) towards the line of sight, are a well established extragalactic TeV $γ$-ray emitters. Since 2006, three nearby and TeV bright blazars, Markarian (Mrk) 421, Mrk 501 and 1ES 1959+650, are regularly observed by the MAGIC telescope with single exposures of 30 to 60 minutes. The sensitivity of MAGIC allows to establish a flux level of 30% of the Crab flux for each such observation. In a case of Mrk 421 strong flux variability in different time scales and a high correlation bet…
The two BL Lac objects 1ES 1215+303 and 1ES 1218+304, separated by 0.8 deg, were observed with the MAGIC telescopes in 2010 and 2011. The 20 hours of data registered in January 2011 resulted in the first detection at Very High Energy (>100 GeV) of 1ES 1215+303 (also known as ON-325). This observation was triggered by a high optical state of the source reported by the Tuorla blazar monitoring program. Comparison with the 25 hours of data carried out from January to May 2010 suggests that 1ES 1215+303 was flaring also in VHE gamma-rays in 2011. In addition, the Swift ToO observations in X-rays s…
We present preliminary results on Dark Matter searches from observations of the Perseus galaxy cluster with the MAGIC Telescopes. MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes located in the Canary island of La Palma, Spain. Galaxy clusters are the largest known gravitationally bound structures in the Universe, with masses of ~10^15 Solar masses. There is strong evidence that galaxy clusters are Dark Matter dominated objects, and therefore promising targets for Dark Matter searches, particularly for decay signals. MAGIC has taken almost 300 hours of data on the Perseus Clus…
GRB 080319B is one of the brightest and most extensively sampled bursts. It has good coverage at many wavelengths. Here we present the optical observations of the Palomar 60 inch telescope, which spans a long time interval after the burst. We augment the optical dataset with freely available Swift BAT and XRT observations reduced by us. We also compare our conclusions with the published parameters from the rich literature about this burst.
Observations and detections of Active Galactic Nuclei (AGN) by Cherenkov telescopes are often triggered by information about high flux states in other wavelength bands. To overcome this bias, the VHE gamma-ray telescope MAGIC has conducted dedicated monitoring observations of nearby AGN since 2006. Three well established, TeV-bright blazars were selected to be observed regularly: Mrk 421, Mrk 501, and 1ES1959+650. The goals of these observations are to obtain an unbiased distribution of flux states shedding light on the duty cycle of AGN, to investigate potential spectral changes during period…
The MAGIC telescope is the largest single-dish Imaging Atmospheric Cherenkov Telescope (IACT) with the lowest energy threshold among the current generation of IACTs as low as 25 GeV. Therefore, the MAGIC telescope is a perfect instrument to study the galactic sources especially in the context of observations with the satellite observatories Fermi and AGILE. This paper will give an overview of the MAGIC results on the galactic sources including detailed observations of binary systems, supernova remnants and the first detection of the Crab pulsar above 25 GeV .
MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov Telescope) is a system of two 17 meters Cherenkov telescopes, sensitive to very high energy (VHE; $> 10^{11}$ eV) gamma radiation above an energy threshold of 50 GeV. The first telescope was built in 2004 and operated for five years in stand-alone mode. A second MAGIC telescope (MAGIC-II), at a distance of 85 meters from the first one, started taking data in July 2009. Together they integrate the MAGIC stereoscopic system. Stereoscopic observations have improved the MAGIC sensitivity and its performance in terms of spectral and angular resol…
We present the first branon dark matter (DM) search in the very high-energy gamma-ray band with observations of the dwarf spheroidal galaxy Segue~1 carried out by the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescope system. Branons are new degrees of freedom that appear in flexible brane-world models corresponding to brane fluctuations. They behave as weakly interacting massive particles, which are natural DM candidates. In the absence of a gamma-ray signal in the Segue~1 data, we place constraints on the branon DM parameter space by using a binned likelihood analysis. Our most cons…
We observed GRB190114C (redshift z = 0.4245), the first GRB ever detected at TeV energies, at optical and near-infrared wavelengths with several ground-based telescopes and the Hubble Space Telescope, with the primary goal of studying its underlying supernova, SN2019jrj. The monitoring spanned the time interval between 1.3 and 370 days after the burst, in the observer frame. We find that the afterglow emission can be modelled with a forward shock propagating in a uniform medium modified by time-variable extinction along the line of sight. A jet break could be present after 7 rest-frame days, a…
MAGIC is a system of two Cherenkov telescopes designed to perform observations of gamma rays with energies from about 50 GeV to tens of TeV. A low energy threshold and an excellent low energy performance make it a powerful instrument for studies of high energy processes in Active Galactic Nuclei (AGN). The MAGIC Collaboration dedicates about 40% of the telescopes' time to such observations, both monitoring of known emitters, and Target of Opportunity observations of flaring events. In this presentation we will discuss the recent highlights of the MAGIC AGN program. In particular, multi year mo…
The MAGIC telescopes are two Imaging Atmospheric Cherenkov Telescopes located on the canary island of La Palma. They provide the lowest energy threshold among existing instruments of the kind, reaching down to 50 GeV in standard trigger mode. This allows us to close the energy gap between satellite-bourne and ground-based gamma-ray observations for strong enough sources. During the first five years of monoscopic observations, many interesting results could thus be achieved. With the second MAGIC telescope, which started operation in 2009, the sensitivity could be improved by stereoscopic imagi…
[Abridged] We present the first comprehensive analysis of HST observations of short-duration gamma-ray burst (GRB) host galaxies. These observations allow us to characterize the galactic and local environments of short GRBs as a powerful constraint on the nature of their progenitors. Using the HST data for 10 short GRB hosts we determine the host morphological properties, measure precise physical and host-normalized offsets relative to the galaxy centers, and study the locations of short GRBs relative to their host light distributions. We find that most short GRB hosts have exponential disk pr…
Indications of a GeV component in the emission from GRBs are known since the EGRET observations during the 1990's and they have been confirmed by the data of the Fermi satellite. These results have, however, shown that our understanding of GRB physics is still unsatisfactory. The new generation of Cherenkov observatories and in particular the MAGIC telescope, allow for the first time the possibility to extend the measurement of GRBs from several tens up to hundreds of GeV energy range. Both leptonic and hadronic processes have been suggested to explain the possible GeV/TeV counterpart of GRBs.…
Very high energy gamma rays coming from extra-galactic sources can interact with intergalactic radiation fields. This process may result in electromagnetic cascades with the following cycle: the production of electron-positron pairs and then secondary gamma-rays due to inverse Compton scattering. Since electrons and positrons will be scattered in the intergalactic magnetic field, under certain conditions their radiation may be redirected towards the observer. Thus one can anticipate that the secondary gamma-ray emission may produce an apparent extended halo around the source. MAGIC is an Imagi…
The non-thermal jet emission in active galactic nuclei covers several orders of magnitude in the frequency range. Hence the observational approach needs multi-wavelength (MWL) campaigns collecting data in the radio, optical, UV, X-rays, high energy until the Very High Energy (VHE) gamma-ray band. MAGIC, a system of two 17 m diameter telescopes at the Roque de los Muchachos observatory on the canary island La Palma, actively participates and organizes MWL observations on known and newly discovered VHE sources. In these proceedings we report the latest results of extra-galactic observations with…
MAGIC comprises two 17m diameter IACTs to be operated in stereo mode. Currently we are commissioning the second telescope, MAGIC II. The camera of the second telescope has been equipped with 1039 pixels of 0.1-degree diameter. Always seven pixels are grouped in a hexagonal configuration to form a cluster. This modular design allows easier control and maintenance of the camera. The pixel sensors are high quantum efficiency photomultiplier tubes (PMTs) from Hamamatsu (superbialkali type, QE ~ 32% at the peak wavelength) that we operate at rather low gain of 30 k. This allows us to also perform e…
The MAGIC gamma-ray observatory has recently been upgraded by a second Cherenkov telescope at a distance of 85 m from the first one. Simultaneous observation of air showers with the two MAGIC telescopes (stereoscopic mode) will improve the reconstruction of the shower axis and solve the ambiguity in the impact point occurring in single-telescope mode. Also, the stereo observation will result in a better angular resolution, energy estimation and cosmic-ray background rejection. It is expected that the sensitivity of MAGIC improves significantly over the full energy range (60 GeV - 20 TeV). Here…
The MAGIC telescopes performed a deep observation of the central region of the Perseus galaxy cluster in stereoscopic mode between October 2009 and February 2011. The nearly 85 hr of collected data (after quality selection) represent the deepest observation of a cluster of galaxies at very high energies (VHE, E > 100 GeV) ever. The survey resulted in the detection of VHE gamma-ray emissions from its central galaxy NGC 1275 and from the radio galaxy IC 310. In addition, the deep survey also permits for the first time to constrain emission models predicting VHE gamma-rays from cosmic-ray acceler…
MAGIC is an instrument composed of a pair of telescopes for gamma- ray and cosmic-ray astrophysics in the TeV range. It is operating for more than a decade now, and is one of the current best performing instruments in this field, specifically at low energies, where it achieves the largest sensitivity. MAGIC pursues a strong program in galactic and extragalactic gamma-ray science. Its catalog of blazars, radiogalaxies and galaxy clusters observations as well as supernovae, novae, pulsar wind nebulae, pulsars and binary systems has now increased to several tens of detected targets. In addition, …
The MAGIC ground-based Imaging Cherenkov experiment observed the Perseus galaxy cluster for a total of about 25 hr between November and December 2008 in single telescope mode and for nearly 90 hr between October 2009 and February 2011 in stereoscopic mode. This survey represents the deepest observation of a cluster of galaxies at very high energies ever. It resulted in the detection of the central radio galaxy NGC 1275 and the head-tail radio galaxy IC 310. It also permits for the first time to put constraints on emission models predicting gamma-rays from cosmic ray acceleration in the cluster…
MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes located at the Canary Island of La Palma, designed to observe gamma rays with energies above 50 GeV. Recently it has undergone an upgrade of the camera, digital trigger and readout systems. The upgrade has led to an improvement in the performance of the telescopes, especially in the lower energy range. We evaluate the performance of the upgraded MAGIC telescopes using Monte Carlo simulations and a large sample of Crab Nebula data. We study differential and integral sensitivity of the system, its angular resolution as well as its…
We report on observations of the Crab pulsar with the MAGIC telescopes. Our data were taken in both monoscopic (> 25GeV) and stereoscopic (> 50GeV) observation modes. Two peaks were detected with both modes and phase-resolved energy spectra were calculated. By comparing with Fermi- LAT measurements, we find that the energy spectrum of the Crab pulsar does not follow a power law with an exponential cutoff, but has an additional hard component, extending up to at least 400 GeV. This suggests that the emission above 25 GeV is not dominated by curvature radiation, as suggested in the standard scen…
Supernova Remnants (SNRs) are believed to be the acceleration sites of galactic cosmic rays. As such they are expected to produce Very High Energy (VHE) gamma-rays through hadronic and/or electromagnetic scenarios, hence they are natural targets for observations with ground-based Imaging Atmospheric Cherenkov Telescopes (IACTs). Currently, VHE emission has been detected from several SNRs, making them one of the most abundant types of established galactic VHE sources. The MAGIC telescope, located in the Canary island of La Palma, has been performing observations of several SNRs over the last tw…
MAGIC has been exploring the sky at Very High Energy gamma-rays (50 GeV - 50 TeV) since 2004, operating first with a single telescope and from 2009 with two telescopes in stereoscopic mode. MAGIC has carried out a observational program involving fundamental physics and astrophysics topics. In this paper we present some of the most important results obtained by MAGIC, with a special emphasis in the most recent ones.
MAGIC is a stereoscopic system of two Imaging Atmospheric Cherenkov Telescopes operating in the very high energy (VHE) range from about 50 GeV to over 50 TeV. The VHE gamma-ray spectra measured at Earth carry an imprint of the extragalactic background light (EBL) and can be used to study the EBL density and its evolution in time. In the last few years, precision measurements of several blazars in the redshift range from z=0.03 up to z=0.9 were performed with MAGIC obtaining strong limits on the EBL density from single sources. In this paper, we present the results from a combined likelihood an…
Gamma-ray bursts (GRBs) that emit photons at GeV energies form a small but significant population of GRBs. However, the number of GRBs whose GeV-emitting period is simultaneously observed in X-rays remains small. We report gamma-ray observations of GRB 110625A using Fermi's Large Area Telescope (LAT) in the energy range 100 MeV to 20 GeV. Gamma-ray emission at these energies was clearly detected using data taken between 180s and 580s after the burst, an epoch after the prompt emission phase. The GeV light curve differs from a simple power-law decay, and probably consists of two emission period…
Cosmic electrons with energies in the TeV range lose their energy rapidly through synchrotron radiation and inverse Compton processes, resulting in a relatively short lifetime (~ 10^5 years). They are only visible from comparatively nearby sources (<1 kpc). Unexpected features in their spectrum at a few hundreds GeV, as measured by several experiments (ATIC, Fermi and H.E.S.S. among others), might be caused by local sources such as pulsars or by dark matter annihilation/decay. In order to investigate these possibilities, new measurements in the TeV energy region are needed. Since the completio…
A planned rapid submillimeter (submm) Gamma Ray Burst (GRBs) follow-up observations conducted using the Greenland Telescope (GLT) is presented. The GLT is a 12-m submm telescope to be located at the top of the Greenland ice sheet, where the high-altitude and dry weather porvides excellent conditions for observations at submm wavelengths. With its combination of wavelength window and rapid responding system, the GLT will explore new insights on GRBs. Summarizing the current achievements of submm GRB follow-ups, we identify the following three scientific goals regarding GRBs: (1) systematic dete…
The two BL Lac objects, 1ES 1215+303 and 1ES 1218+304, separated by 0.8 degree, were observed with the MAGIC Cherenkov telescopes in 2010-2011. The January 2011 observations resulted in the first detection above 100 GeV of 1ES 1215+303 (known also as ON-325) which has been flagged as a promising Very High Energy (VHE, E > 100 GeV) gamma-ray source candidate by the Fermi-LAT Collaboration in October 2010. The January 2011 observations were triggered by the high optical state of the source, as reported by the Tuorla blazar monitoring program. A comparison with the 2010 data suggests that 1ES 121…
In the last few years the Fermi -LAT instrument has detected GeV gamma-ray emission from a few novae. Such GeV emission can be interpreted in terms of an inverse Compton process of electrons accelerated in a shock. It is expected that hadrons can be accelerated in the same conditions, but reaching much higher energies. They can produce a second component in the gamma-ray spectrum at TeV energies. We performed follow-up observations of selected novae and dwarf novae in a search of the second component in the gamma-ray spectrum. This can shed light on the acceleration process of leptons and hadr…
We report on the observations of the Crab pulsar with the MAGIC telesopes. Data were taken both in the mono-mode ($>25$ GeV) and in the stereo-mode ($>50$ GeV). Clear signals from the two peaks were detected with both modes and the phase resolved energy spectra were calculated. By comparing with the measurements done by Fermi-LAT, we found that the energy spectra of the Crab pulsar does not follow a power law with an exponential cutoff, but that it extends as a power law after the break at around 5 GeV. This suggests that the emission above 25 GeV is not dominated by the curvatura radiation, w…
Testing the ubiquitous presence of very high energy emission in gamma-ray bursts with the MAGIC telescopes
Institute for Cosmic Ray Research (ICRR), The University of Tokyo（东京大学宇宙射线研究所）；ETH Zürich（苏黎世联邦理工学院）；Università di Siena and INFN Pisa（锡耶纳大学和比萨INFN）；Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology (BIST)（巴塞罗那科学与技术高等物理研究所）；Universitat de Barcelona, ICCUB, IEEC-UB（巴塞罗那大学）；Instituto de Astrofísica de Andalucía-CSIC（安达卢西亚天体物理学研究所-CSIC）；National Institute for Astrophysics (INAF)（国家天体物理研究所）；Università di Udine and INFN Trieste（乌迪内大学和的里雅斯特INFN）；International Center for Relativistic Astrophysics (ICRA)（国际相对论天体物理中心）；Max-Planck-Institut für Physik（马克斯·普朗克物理研究所）；Università di Padova and INFN（帕多瓦大学和INFN）；Instituto de Astrofísica de Canarias and Dpto. de Astrofísica, Universidad de La Laguna（加那利天体物理学研究所和拉古纳大学天体物理学系）；University of Zagreb, Faculty of Elec（萨格勒布大学）
Despite the interest in Dark Matter (DM) searches is currently more focused on underground experiments, a signature of DM annihilation/decay in gamma-rays from the space would constitute a smoking gun for its identification. Here, we present the results of the survey of Segue1 by the MAGIC-I telescope performed in 2008 and 2009. This source is considered by many as the most DM dominated Milky Way satellite galaxy known so far. The nearly 43 hours of data taken constitute the deepest observation ever made on a single dwarf galaxy by Cherenkov telescopes. No significant gamma-ray emission was fo…
The improvement on the Imaging Air Cherenkov Technique (IACT) led to the discovery of a new type of sources that can emit at very high energies: the gamma-ray binaries. Only six systems are part of this exclusive class. We summarize the latest results from the observations performed with the MAGIC telescopes on different systems as the gamma-ray binary LS I +61$^{\circ}$ 303 and the microquasars SS433, V404 Cygni and Cygnus X-1, which are considered potential VHE gamma-ray emitters. The binary system LS I +61$^{\circ}$ 303 has been observed by MAGIC in a long-term monitoring campaign. We show …
MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes sensitive above ~60 GeV, and located on the Canary Island of La Palma at the height of 2200 m.a.s.l. Since Autumn 2009 both telescopes are working together in stereoscopic mode. We use both Crab Nebula observations and Monte Carlo simulations to evaluate the performance of the system. Advanced stereo analysis allows MAGIC to achieve a sensitivity better than 0.8% of the Crab Nebula flux in 50 h of observations in the medium energy range (around a few hundred GeV). At those energies the angular resolution is better than 0.07{\cir…
Based on MAGIC observations from June and July 2007, we have obtained an integral upper limit to the VHE energy emission of the globular cluster M13 of $F(E>200 \textrm{GeV})<5.1\times10^{-12} \textrm{cm}^{-2} \textrm{s}^{-1}$, and differential upper limits for $E>140 \textrm{GeV}$. Those limits allow us to constrain the population of millisecond pulsars within M13 and to test models for acceleration of leptons inside their magnetospheres and surrounding. We conclude that in M13 either millisecond pulsars are fewer than expected or they accelerate leptons less efficiently than predicted.
Several binary systems, composed of a star and a compact object, have been detected in the GeV-TeV range. Several systems have been observed but only a handful of sources have shown emission at those energies. Here, we present the observations conducted by MAGIC of different γ-ray binary systems. On one hand, we show the latest studies on the binary system LS I +61 303, which displays variability on different timescales. With the latest MAGIC observations, we will try to shed light on our understanding of this source, by presenting super-orbital and multi-wavelength studies. On the other hand,…
The MAGIC telescopes discovered very high energy (VHE, E>100 GeV) gamma-ray emission coming from the distant Flat Spectrum Radio Quasar (FSRQ) PKS 1222+21 (4C +21.35, z=0.432). It is the second most distant VHE gamma-ray source, with well measured redshift, detected until now. The observation was performed on 2010 June 17 (MJD 55364.9) using the two 17 m diameter imaging Cherenkov telescopes on La Palma (Canary Islands, Spain). The MAGIC detection coincides with high energy MeV/GeV gamma-ray activity measured by the Large Area Telescope (LAT) on board the Fermi satellite. The averaged integral…
Gamma rays at rest frame energies as high as 90 GeV have been reported from gamma-ray bursts (GRBs) by the Fermi Large Area Telescope (LAT). There is considerable hope that a confirmed GRB detection will be possible with the upcoming Cherenkov Telescope Array (CTA), which will have a larger effective area and better low-energy sensitivity than current-generation imaging atmospheric Cherenkov telescopes (IACTs). To estimate the likelihood of such a detection, we have developed a phenomenological model for GRB emission between 1 GeV and 1 TeV that is motivated by the high-energy GRB detections o…
The gamma-ray binary system LS I +61 303 was studied in great detail in VHE gamma-rays in the last years by the MAGIC telescope. The VHE emission of the system exhibited a prominent periodic outburst in the orbital phases 0.6-0.7 between September 2005 to January 2008. In Fall 2008 the Fermi collaboration reported as well periodic emission in the MeV to GeV energy range, but with a shifted outburst in the phases 0.35-0.45. MAGIC observed again LS I+61 303 in 2009 with the twice more sensitive stereo mode to allow for detailed correlation studies between the VHE gamma-ray and Fermi/LAT energy b…
About one month after the revolutionary discovery of the Gamma Ray Burst (GRB) GRB 221009A and intense theoretical efforts to explain its detection, time seems to us ripe to make an assessment of the axion-like particle (ALP) based scenarios, since it is a common belief that conventional physics would have prevented such a detection. We overcome the almost complete lack of information -- so far only astronomical telegrams have been released -- by relying as much as possible upon the analogy with the emission from the GRB 190114C detected by the MAGIC collaboration in 2019, since it was the hig…
HESS J1857+026 is an extended TeV gamma-ray source discovered by H.E.S.S. very close to the Galactic plane. Located in the vicinity of the pulsar PSR J1856+0245, the source represents a pulsar wind nebula (PWN) candidate. In Fermi-LAT data, 7 photons above 100GeV were associated to it as VHE J1857+0252 by Neronov and Semikoz (2010), while in the previous MeV-GeV catalogs no associated source was reported yet. MAGIC was upgraded to a stereoscopic Cherenkov telescope system in 2009, which substantially improved its performance with respect to extended objects. We observed HESS J1857+026 in 2010 …
3C 66A is an intermediate-frequency peaked BL Lacertae object of uncertain redshift. We report recent observations of the region around the blazar with the MAGIC telescopes. The source was observed and detected in 2009 December and 2010 January, in 2.3 h of good quality data. The signal could clearly be assigned to the blazar 3C 66A, statistically and systematically rejecting the nearby radio galaxy 3C 66B as a possible origin of the gamma-ray signal by 3.6 standard deviations. The derived integral flux above 100GeV is 8.3% of the Crab Nebula flux, and the energy spectrum is reproduced by a po…
We report on optical observations of Gamma-Ray Bursts (GRBs) followed up by our collaboration with the 1.23m telescope located at the Calar Alto observatory. The 1.23m telescope is an old facility, currently undergoing upgrades to enable fully autonomous response to GRB alerts. We discuss the current status of the control system upgrade of the 1.23m telescope. The upgrade is being done by the ARAE our group, based on members of IAA (Instituto de Astrofiisica de Andalucia). Currently the ARAE group is responsible to develop the BOOTES network of robotic telescopes based on the Remote Telescope …
QSO B0218+357 is a blazar located at a cosmological redshift of z=0.944. It is gravitationally lensed by a spiral galaxy at a redshift of z=0.68. The blazar and its lens are well studied in the radio through X-ray bands, and several blazar outbursts were detected by Fermi-LAT at energies above 100 MeV. Strong gravitational lensing was invoked to explain the two components appar- ent in the radio and GeV light curves, separated by 10-12 days. In July 2014 another outburst was observed by Fermi-LAT, triggering follow-up observations with the MAGIC telescopes at energies above 100 GeV. The observ…
Since it is not possible to predict when a Gamma-Ray Burst (GRB) will occur or when Active Galactic Nucleus (AGN) flaring activity starts, follow-up/monitoring ground telescopes must be located as uniformly as possible all over the world in order to collect data simultaneously with Fermi and Swift detections. However, there is a distinct gap in follow-up coverage of telescopes in the eastern U.S. region based on the operations of Swift. Motivated by this fact, we have constructed a 14" fully automated optical robotic telescope, Goddard Robotic Telescope (GRT), at the Goddard Geophysical and As…
