Results for "Domini Jocema Leko"

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Chatterjea type fixed point in Partial $b$-metric spacesFeb 08 2019In this paper, we give and prove two Chatterjea type fixed point theorems on partial $b$-metric space. We propose an extension to the Banach contraction principle on partial $b$-metric space which was already presented by Shukla and also study some related ... More
alpha'-exact entropies for BPS and non-BPS extremal dyonic black holes in heterotic string theory from ten-dimensional supersymmetrySep 29 2008Dec 10 2008We calculate near-horizon solutions for four-dimensional 4-charge and five-dimensional 3-charge black holes in heterotic string theory from the part of the ten-dimensional tree-level effective action which is connected to gravitational Chern-Simons term ... More
alpha'^2-corrections to extremal dyonic black holes in heterotic string theoryOct 20 2007May 21 2008We calculate alpha'^2-corrections to the entropy of the 5-dimensional 3-charge and the 4-dimensional 4-charge large extremal black holes using the low energy effective action of the heterotic string theory. In the 4-dimensional case, our results are in ... More
An abundance analysis for Vega: Is it a lambda Boo star?May 18 1998Since Baschek & Slettebak (1988) drew attention to the similarity between the abundance pattern of lambda Boo stars and that of Vega, there has been a long debate whether Vega should be listed among the chemically peculiar stars of lambda Boo type. We ... More
Worldline quantization of field theory, effective actions and $L_\infty$ structureFeb 08 2018We formulate the worldline quantization of a massive fermion model coupled to external higher spin sources. We use the relations obtained in this way to show that its regularized effective action is endowed with an $L_\infty$ symmetry. The same result ... More
One-loop effective actions and higher spinsSep 07 2016Nov 14 2016The idea we advocate in this paper is that the one-loop effective action of a free (massive) field theory coupled to external sources (via conserved currents) contains complete information about the classical dynamics of such sources. We show many explicit ... More
Axial gravity, massless fermions and trace anomaliesMar 30 2017May 24 2017This article deals with two main topics. One is odd parity trace anomalies in Weyl fermion theories in a 4d curved background, the second is the introduction of axial gravity. The motivation for reconsidering the former is to clarify the theoretical background ... More
Parity-odd surface anomalies and correlation functions on conical defectsMar 20 2015Dec 01 2015We analyse the parity-odd ("type P") surface anomalies of the energy-momentum tensor correlators in conformal field theories, with an emphasis on d=4 and d=3 dimensional spacetimes. Using cohomology analysis we construct the expression for the most general ... More
MAGIC observations of the giant radio galaxy M87 in a low emission state between 2005 and 2007Sep 27 2011We present the results of a long M87 monitoring campaign in very high energy $\gamma$-rays with the MAGIC-I Cherenkov telescope. A total of 150 hours of data was gathered between 2005 and 2007. No flaring activity was found during that time. Nevertheless, ... More
One-loop effective actions and higher spinsSep 07 2016Sep 15 2016The idea we advocate in this paper is that the one-loop effective action of a free (massive) field theory coupled to external sources (via conserved currents) contains complete information about the classical dynamics of such sources. We show many explicit ... More
Five-dimensional black holes in heterotic string theoryNov 30 2007We review recent results on near-horizon static black hole solutions and entropy in R^2-corrected N=2 SUGRA in D=5, focusing on actions connected to heterotic string compactified on K3\times S^1. Comparison with \alpha'-perturbative results, results obtained ... More
Detection of very-high-energy gamma rays from the most distant and gravitationally lensed blazar QSO B0218+357 using the MAGIC telescope systemAug 19 2015QSO 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 ... More
Latest MAGIC discoveries pushing redshift boundaries in VHE AstrophysicsJun 14 2016The search for detection of gamma-rays from distant AGNs by Imaging Atmospheric Cherenkov Telescopes (IACTs) is challenging at high redshifts, not only because of lower flux due to the distance of the source, but also due to the consequent absorption ... More
RoboNet-II: Follow-up observations of microlensing events with a robotic network of telescopesAug 06 2008Oct 24 2008RoboNet-II uses a global network of robotic telescopes to perform follow-up observations of microlensing events in the Galactic Bulge. The current network consists of three 2m telescopes located in Hawaii and Australia (owned by Las Cumbres Observatory) ... More
Towards A Census of Earth-mass Exo-planets with Gravitational MicrolensingJul 31 2008Thirteen exo-planets have been discovered using the gravitational microlensing technique (out of which 7 have been published). These planets already demonstrate that super-Earths (with mass up to ~10 Earth masses) beyond the snow line are common and multiple ... More
Difference imaging photometry of blended gravitational microlensing events with a numerical kernelMay 18 2009The numerical kernel approach to difference imaging has been implemented and applied to gravitational microlensing events observed by the PLANET collaboration. The effect of an error in the source-star coordinates is explored and a new algorithm is presented ... More
Full characterization of binary-lens event OGLE-2002-BLG-069 from PLANET observationsFeb 01 2005We analyze the photometric data obtained by PLANET and OGLE on the caustic-crossing binary-lens microlensing event OGLE-2002-BLG-069. Thanks to the excellent photometric and spectroscopic coverage of the event, we are able to constrain the lens model ... More
Evidence for a Supernova Associated with the X-ray Flash 020903Feb 07 2006We present ground-based and Hubble Space Telescope optical observations of the X-ray flash (XRF) 020903, covering 300 days. The afterglow showed a very rapid rise in the first day, followed by a relatively slow decay in the next few days. There was a ... More
OGLE 2004-BLG-254: a K3 III Galactic Bulge Giant spatially resolved by a single microlensSep 11 2006We present an analysis of OGLE 2004-BLG-254, a high-magnification and relatively short duration microlensing event in which the source star, a Bulge K3-giant, has been spatially resolved by a point-like lens. We have obtained dense photometric coverage ... More
One or more bound planets per Milky Way star from microlensing observationsFeb 04 2012Most known extrasolar planets (exoplanets) have been discovered using the radial velocity$^{\bf 1,2}$ or transit$^{\bf 3}$ methods. Both are biased towards planets that are relatively close to their parent stars, and studies find that around 17--30% (refs ... More
A systematic fitting scheme for caustic-crossing microlensing eventsJan 09 2009We outline a method for fitting binary-lens caustic-crossing microlensing events based on the alternative model parameterisation proposed and detailed in Cassan (2008). As an illustration of our methodology, we present an analysis of OGLE-2007-BLG-472, ... More
Discovery of a Cool Planet of 5.5 Earth Masses Through Gravitational MicrolensingJan 25 2006In the favoured core-accretion model of formation of planetary systems, solid planetesimals accumulate to build up planetary cores, which then accrete nebular gas if they are sufficiently massive. Around M-dwarf stars (the most common stars in our Galaxy), ... More
OGLE-2005-BLG-018: Characterization of Full Physical and Orbital Parameters of a Gravitational Binary LensApr 27 2011We present the analysis result of a gravitational binary-lensing event OGLE-2005-BLG-018. The light curve of the event is characterized by 2 adjacent strong features and a single weak feature separated from the strong features. The light curve exhibits ... More
Limb-darkening measurements for a cool red giant in microlensing event OGLE 2004-BLG-482Dec 11 2009Sep 28 2010Aims: We present a detailed analysis of OGLE 2004-BLG-482, a relatively high-magnification single-lens microlensing event which exhibits clear extended-source effects. These events are relatively rare, but they potentially contain unique information on ... More
Gravitational Binary-lens Events with Prominent Effects of Lens Orbital MotionJun 17 2013Gravitational microlensing events produced by lenses composed of binary masses are important because they provide a major channel to determine physical parameters of lenses. In this work, we analyze the light curves of two binary-lens events OGLE-2006-BLG-277 ... More
The First Planetary Microlensing Event with Two Microlensed Source StarsJul 30 2017Mar 22 2018We present the analysis of microlensing event MOA-2010-BLG-117, and show that the light curve can only be explained by the gravitational lensing of a binary source star system by a star with a Jupiter mass ratio planet. It was necessary to modify standard ... More
MOA-2007-BLG-197: Exploring the brown dwarf desertMay 22 2015We present the analysis of MOA-2007-BLG-197Lb, the first brown dwarf companion to a Sun-like star detected through gravitational microlensing. The event was alerted and followed-up photometrically by a network of telescopes from the PLANET, MOA, and uFUN ... More
Mass measurement of a single unseen star and planetary detection efficiency for OGLE 2007-BLG-050Jul 20 2009Jul 22 2009We analyze OGLE-2007-BLG-050, a high magnification microlensing event (A ~ 432) whose peak occurred on 2 May, 2007, with pronounced finite-source and parallax effects. We compute planet detection efficiencies for this event in order to determine its sensitivity ... More
A possible binary system of a stellar remnant in the high magnification gravitational microlensing event OGLE-2007-BLG-514Jul 05 2012We report the extremely high magnification (A > 1000) binary microlensing event OGLE-2007-BLG-514. We obtained good coverage around the double peak structure in the light curve via follow-up observations from different observatories. The binary lens model ... More
OGLE-2005-BLG-153: Microlensing Discovery and Characterization of A Very Low Mass BinarySep 02 2010Apr 25 2012The mass function and statistics of binaries provide important diagnostics of the star formation process. Despite this importance, the mass function at low masses remains poorly known due to observational difficulties caused by the faintness of the objects. ... More
Red noise versus planetary interpretations in the microlensing event OGLE-2013-BLG-446Oct 09 2015Oct 28 2015For all exoplanet candidates, the reliability of a claimed detection needs to be assessed through a careful study of systematic errors in the data to minimize the false positives rate. We present a method to investigate such systematics in microlensing ... More
A Cold Neptune-Mass Planet OGLE-2007-BLG-368Lb: Cold Neptunes Are CommonDec 07 2009Jan 22 2010We present the discovery of a Neptune-mass planet OGLE-2007-BLG-368Lb with a planet-star mass ratio of q=[9.5 +/- 2.1] x 10^{-5} via gravitational microlensing. The planetary deviation was detected in real-time thanks to the high cadence of the MOA survey, ... More
OGLE-2008-BLG-510: first automated real-time detection of a weak microlensing anomaly - brown dwarf or stellar binary?Mar 06 2012The microlensing event OGLE-2008-BLG-510 is characterised by an evident asymmetric shape of the peak, promptly detected by the ARTEMiS system in real time. The skewness of the light curve appears to be compatible both with binary-lens and binary-source ... More
The First Circumbinary Planet Found by Microlensing: OGLE-2007-BLG-349L(AB)cSep 21 2016We present the analysis of the first circumbinary planet microlensing event, OGLE-2007-BLG-349. This event has a strong planetary signal that is best fit with a mass ratio of $q \approx 3.4\times 10^{-4}$, but there is an additional signal due to an additional ... More
A Sub-Earth-Mass Moon Orbiting a Gas Giant Primary or a High Velocity Planetary System in the Galactic BulgeDec 13 2013We present the first microlensing candidate for a free-floating exoplanet-exomoon system, MOA-2011-BLG-262, with a primary lens mass of M_host ~ 4 Jupiter masses hosting a sub-Earth mass moon. The data are well fit by this exomoon model, but an alternate ... More
Binary microlensing event OGLE-2009-BLG-020 gives a verifiable mass, distance and orbit predictionsJan 17 2011We present the first example of binary microlensing for which the parameter measurements can be verified (or contradicted) by future Doppler observations. This test is made possible by a confluence of two relatively unusual circumstances. First, the binary ... More
Interpretation of a Short-Term Anomaly in the Gravitational Microlensing Event MOA-2012-BLG-486Aug 27 2013A planetary microlensing signal is generally characterized by a short-term perturbation to the standard single lensing light curve. A subset of binary-source events can produce perturbations that mimic planetary signals, thereby introducing an ambiguity ... More
Discovery of TeV gamma-ray emission from the pulsar wind nebula 3C 58 by MAGICMay 23 2014Jul 09 2014The pulsar wind nebula (PWN) 3C 58 is one of the historical very-high-energy (VHE; E>100 GeV) gamma-ray source candidates. It is energized by one of the highest spin-down power pulsars known (5% of Crab pulsar) and it has been compared to the Crab Nebula ... More
MAGIC TeV Gamma-Ray Observations of Markarian 421 during Multiwavelength Campaigns in 2006Jan 08 2010Aug 03 2010The Major Atmospheric Gamma Imaging Cerenkov (MAGIC) telescope participated in three multiwavelength (MWL) campaigns, observing the blazar Markarian (Mkn) 421 during the nights of 2006 April 28, 29, and 2006 June 14. We analyzed the corresponding MAGIC ... More
MOA-2010-BLG-311: A planetary candidate below the threshold of reliable detectionOct 22 2012Oct 10 2013We analyze MOA-2010-BLG-311, a high magnification (A_max>600) microlensing event with complete data coverage over the peak, making it very sensitive to planetary signals. We fit this event with both a point lens and a 2-body lens model and find that the ... More
OGLE-2011-BLG-0265Lb: a Jovian Microlensing Planet Orbiting an M DwarfOct 30 2014Feb 24 2015We report the discovery of a Jupiter-mass planet orbiting an M-dwarf star that gave rise to the microlensing event OGLE-2011-BLG-0265. Such a system is very rare among known planetary systems and thus the discovery is important for theoretical studies ... More
MOA-2010-BLG-073L: An M-Dwarf with a Substellar Companion at the Planet/Brown Dwarf BoundaryNov 16 2012Dec 11 2012We present an analysis of the anomalous microlensing event, MOA-2010-BLG-073, announced by the Microlensing Observations in Astrophysics survey on 2010-03-18. This event was remarkable because the source was previously known to be photometrically variable. ... More
Pathway to the Galactic Distribution of Planets: Combined Spitzer and Ground-Based Microlens Parallax Measurements of 21 Single-Lens EventsNov 26 2014Feb 24 2015We present microlens parallax measurements for 21 (apparently) isolated lenses observed toward the Galactic bulge that were imaged simultaneously from Earth and Spitzer, which was ~1 AU West of Earth in projection. We combine these measurements with a ... More
OGLE-2005-BLG-071Lb, the Most Massive M-Dwarf Planetary Companion?Apr 09 2008Jun 03 2009We combine all available information to constrain the nature of OGLE-2005-BLG-071Lb, the second planet discovered by microlensing and the first in a high-magnification event. These include photometric and astrometric measurements from Hubble Space Telescope, ... More
Reanalyses of Anomalous Gravitational Microlensing Events in the OGLE-III Early Warning System Database with Combined DataFeb 24 2015Mar 02 2015We reanalyze microlensing events in the published list of anomalous events that were observed from the OGLE lensing survey conducted during 2004-2008 period. In order to check the existence of possible degenerate solutions and extract extra information, ... More
The First Circumbinary Planet Found by Microlensing: OGLE-2007-BLG-349L(AB)cSep 21 2016Nov 03 2016We present the analysis of the first circumbinary planet microlensing event, OGLE-2007-BLG-349. This event has a strong planetary signal that is best fit with a mass ratio of $q \approx 3.4\times10^{-4}$, but there is an additional signal due to an additional ... More
OGLE 2008--BLG--290: An accurate measurement of the limb darkening of a Galactic Bulge K Giant spatially resolved by microlensingMay 06 2010Gravitational microlensing is not only a successful tool for discovering distant exoplanets, but it also enables characterization of the lens and source stars involved in the lensing event. In high magnification events, the lens caustic may cross over ... More
MAGIC observations of MWC 656, the only known Be/BH systemFeb 05 2015Feb 09 2015Context: MWC 656 has recently been established as the first observationally detected high-mass X-ray binary system containing a Be star and a black hole (BH). The system has been associated with a gamma-ray flaring event detected by the AGILE satellite ... More
MAGIC Upper Limits for two Milagro-detected, Bright Fermi Sources in the Region of SNR G65.1+0.6Jul 20 2010Apr 04 2011We report on the observation of the region around supernova remnant G65.1+0.6 with the stand-alone MAGIC-I telescope. This region hosts the two bright GeV gamma-ray sources 1FGL J1954.3+2836 and 1FGL J1958.6+2845. They are identified as GeV pulsars and ... More
MAGIC observations and multiwavelength properties of the quasar 3C279 in 2007 and 2009Jan 13 2011Mar 02 2011Context. 3C 279, the first quasar discovered to emit VHE gamma-rays by the MAGIC telescope in 2006, was reobserved by MAGIC in January 2007 during a major optical flare and from December 2008 to April 2009 following an alert from the Fermi space telescope ... More
A New Type of Ambiguity in the Planet and Binary Interpretations of Central Perturbations of High-Magnification Gravitational Microlensing EventsApr 21 2012Apr 25 2012High-magnification microlensing events provide an important channel to detect planets. Perturbations near the peak of a high-magnification event can be produced either by a planet or a binary companion. It is known that central perturbations induced by ... More
MOA-2010-BLG-328Lb: a sub-Neptune orbiting very late M dwarf ?Sep 30 2013Oct 10 2013We analyze the planetary microlensing event MOA-2010-BLG-328. The best fit yields host and planetary masses of Mh = 0.11+/-0.01 M_{sun} and Mp = 9.2+/-2.2M_Earth, corresponding to a very late M dwarf and sub-Neptune-mass planet, respectively. The system ... More
MAGIC discovery of VHE Emission from the FSRQ PKS 1222+21Jan 24 2011Mar 04 2011Very High Energy (VHE) gamma-ray emission from the flat spectrum radio quasar (FSRQ) PKS 1222+21 (4C 21.35, z=0.432) was detected with the MAGIC Cherenkov telescopes during a short observation (~0.5 hr) performed on 2010 June 17. The MAGIC detection coincides ... More
A Giant Planet beyond the Snow Line in Microlensing Event OGLE-2011-BLG-0251Mar 05 2013We present the analysis of the gravitational microlensing event OGLE-2011-BLG-0251. This anomalous event was observed by several survey and follow-up collaborations conducting microlensing observations towards the Galactic Bulge. Based on detailed modelling ... More
MOA-2010-BLG-523: "Failed Planet" = RS CVn StarOct 22 2012Oct 26 2012The Galactic bulge source MOA-2010-BLG-523S exhibited short-term deviations from a standard microlensing lightcurve near the peak of an Amax ~ 265 high-magnification microlensing event. The deviations originally seemed consistent with expectations for ... More
Discovery and Mass Measurements of a Cold, 10-Earth Mass Planet and Its Host StarJun 10 2011We present the discovery and mass measurement of the cold, low-mass planet MOA-2009-BLG-266Lb, made with the gravitational microlensing method. This planet has a mass of m_p = 10.4 +- 1.7 Earth masses and orbits a star of mass M_* = 0.56 +- 0.09 Solar ... More
MOA-2010-BLG-477Lb: constraining the mass of a microlensing planet from microlensing parallax, orbital motion and detection of blended lightMay 29 2012Microlensing detections of cool planets are important for the construction of an unbiased sample to estimate the frequency of planets beyond the snow line, which is where giant planets are thought to form according to the core accretion theory of planet ... More
The blazar TXS 0506+056 associated with a high-energy neutrino: insights into extragalactic jets and cosmic ray accelerationJul 11 2018Jul 30 2018A neutrino with energy of $\sim$290 TeV, IceCube-170922A, was detected in coincidence with the BL Lac object TXS~0506+056 during enhanced gamma-ray activity, with chance coincidence being rejected at $\sim 3\sigma$ level. We monitored the object in the ... More
Microlensing Discovery of a Population of Very Tight, Very Low-mass Binary Brown DwarfsFeb 18 2013Mar 20 2013Although many models have been proposed, the physical mechanisms responsible for the formation of low-mass brown dwarfs are poorly understood. The multiplicity properties and minimum mass of the brown-dwarf mass function provide critical empirical diagnostics ... More
Characterizing Low-Mass Binaries From Observation of Long Time-scale Caustic-crossing Gravitational Microlensing EventsApr 13 2012Jun 13 2012Despite astrophysical importance of binary star systems, detections are limited to those located in small ranges of separations, distances, and masses and thus it is necessary to use a variety of observational techniques for a complete view of stellar ... More
A Super-Jupiter orbiting a late-type star: A refined analysis of microlensing event OGLE-2012-BLG-0406Oct 09 2013Dec 05 2013We present a detailed analysis of survey and follow-up observations of microlensing event OGLE-2012-BLG-0406 based on data obtained from 10 different observatories. Intensive coverage of the lightcurve, especially the perturbation part, allowed us to ... More
MAGIC observations of the February 2014 flare of 1ES 1011+496 and ensuing constraint of the EBL densityFeb 16 2016Feb 18 2016In February-March 2014, the MAGIC telescopes observed the high-frequency peaked BL Lac 1ES 1011+496 (z=0.212) in flaring state at very-high energy (VHE, E>100GeV). The flux reached a level more than 10 times higher than any previously recorded flaring ... More
Observation of the Black Widow B1957+20 millisecond pulsar binary system with the MAGIC telescopesJun 05 2017B1957+20 is a millisecond pulsar located in a black widow type compact binary system with a low mass stellar companion. The interaction of the pulsar wind with the companion star wind and/or the interstellar plasma is expected to create plausible conditions ... More
Detection of bridge emission above 50 GeV from the Crab pulsar with the MAGIC telescopesFeb 18 2014May 02 2014The Crab pulsar is the only astronomical pulsed source detected at very high energy (VHE, E>100GeV) gamma-rays. The emission mechanism of VHE pulsation is not yet fully understood, although several theoretical models have been proposed. In order to test ... More
MAGIC reveals a complex morphology within the unidentified gamma-ray source HESS J1857+026Jan 28 2014Aug 20 2014HESS J1857+026 is an extended TeV gamma-ray source that was discovered by H.E.S.S. as part of its Galactic plane survey. Given its broadband spectral energy distribution and its spatial coincidence with the young energetic pulsar PSR J1856+0245, the source ... More
Black hole lightning due to particle acceleration at subhorizon scalesDec 16 2014Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry, but still suffer from insufficient angular resolution. An alternative ... More
A search for Very High Energy gamma-ray emission from Scorpius X-1 with the MAGIC telescopesMar 29 2011Jun 08 2011The acceleration of particles up to GeV or higher energies in microquasars has been the subject of considerable theoretical and observational efforts in the past few years. Sco X-1 is a microquasar from which evidence of highly energetic particles in ... More
Gamma-ray excess from a stacked sample of high- and intermediate-frequency peaked blazars observed with the MAGIC telescopeFeb 15 2010Jan 14 2011Between 2004 and 2009 a sample of 28 X-ray selected high- and intermediate-frequency peaked blazars with a X-ray flux larger than 2 uJy at 1 keV in the redshift range from 0.018 to 0.361 was observed with the MAGIC telescope at energies above 100 GeV. ... More
MAGIC observations of the giant radio galaxy M87 in a low-emission state between 2005 and 2007Jul 09 2012Jul 11 2012We present the results of a long M87 monitoring campaign in very high energy $\gamma$-rays with the MAGIC-I Cherenkov telescope. We aim to model the persistent non-thermal jet emission by monitoring and characterizing the very high energy $\gamma$-ray ... More
Multi-wavelength characterization of the blazar S5~0716+714 during an unprecedented outburst phaseJul 01 2018The BL Lac object S5~0716+714, a highly variable blazar, underwent an impressive outburst in January 2015 (Phase A), followed by minor activity in February (Phase B). The MAGIC observations were triggered by the optical flux observed in Phase A, corresponding ... More
Insights into the emission of the blazar 1ES 1011+496 through unprecedented broadband observations during 2011 and 2012Mar 22 2016Jun 06 20161ES 1011+496 $(z=0.212)$ was discovered in very high energy (VHE, E >100 GeV) $\gamma$-rays with MAGIC in 2007. The absence of simultaneous data at lower energies led to a rather incomplete characterization of the broadband spectral energy distribution ... More
The major upgrade of the MAGIC telescopes, Part I: The hardware improvements and the commissioning of the systemSep 22 2014Apr 30 2015The MAGIC telescopes are two Imaging Atmospheric Cherenkov Telescopes (IACTs) located on the Canary island of La Palma. The telescopes are designed to measure Cherenkov light from air showers initiated by gamma rays in the energy regime from around 50 ... More
High zenith angle observations of PKS 2155-304 with the MAGIC-I telescopeJul 06 2012The high frequency peaked BL Lac PKS 2155-304 with a redshift of z=0.116 was discovered in 1997 in the very high energy (VHE, E >100GeV) gamma-ray range by the University of Durham Mark VI gamma-ray Cherenkov telescope in Australia with a flux corresponding ... More
The major upgrade of the MAGIC telescopes, Part II: A performance study using observations of the Crab NebulaSep 19 2014Feb 20 2015MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes located in the Canary island of La Palma, Spain. During summer 2011 and 2012 it underwent a series of upgrades, involving the exchange of the MAGIC-I camera and its trigger system, as well ... More
Gamma-ray flaring activity of NGC 1275 in 2016-2017 measured by MAGICJun 05 2018We report on the detection of flaring activity from the Fanaroff-Riley I radio galaxy NGC 1275 in very-high-energy (VHE, E $>$ 100 GeV) gamma rays with the MAGIC telescopes. Observations were performed between 2016 September and 2017 February as part ... More
Deep observation of the NGC 1275 region with MAGIC: search of diffuse gamma-ray emission from cosmic rays in the Perseus clusterFeb 09 2016Clusters of galaxies are expected to be reservoirs of cosmic rays (CRs) that should produce diffuse gamma-ray emission due to their hadronic interactions with the intra-cluster medium. The nearby Perseus cool-core cluster, identified as the most promising ... More
Microlensig Binaries with Candidate Brown Dwarf CompanionsAug 11 2012Oct 03 2012Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation history. In this paper, we present the candidate binaries with brown dwarf companions that ... More
First Multi-wavelength Campaign on the Gamma-ray-loud Active Galaxy IC 310Mar 22 2017The extragalactic VHE gamma-ray sky is rich in blazars. These are jetted active galactic nuclei viewed at a small angle to the line-of-sight. Only a handful of objects viewed at a larger angle are known so far to emit above 100 GeV. Multi-wavelength studies ... More
Super-orbital variability of LS I +61°303 at TeV energiesMar 22 2016Apr 21 2016The gamma-ray binary LS I +61$^{\circ}$303 is a well established source from centimeter radio up to very high energy (VHE; E$>$100 GeV). Its broadband emission shows a periodicity of $\sim$26.5 days, coincident with the orbital period. A longer (super-orbital) ... More
Measurement of the Crab Nebula spectrum over three decades in energy with the MAGIC telescopesJun 26 2014Jul 22 2015The MAGIC stereoscopic system collected 69 hours of Crab Nebula data between October 2009 and April 2011. Analysis of this data sample using the latest improvements in the MAGIC stereoscopic software provided an unprecedented precision of spectral and ... More
MAGIC observations and multifrequency properties of the Flat Spectrum Radio Quasar 3C 279 in 2011Nov 12 2013Jul 07 2014We study the multifrequency emission and spectral properties of the quasar 3C 279. We observed 3C 279 in very high energy (VHE, E>100GeV) gamma rays, with the MAGIC telescopes during 2011, for the first time in stereoscopic mode. We combine these measurements ... More
Observations of the magnetars 4U 0142+61 and 1E 2259+586 with the MAGIC telescopesNov 06 2012Nov 08 2012Magnetars are an extreme, highly magnetized class of isolated neutron stars whose large X-ray luminosity is believed to be driven by their high magnetic field. In this work we study for the first time the possible very high energy gamma-ray emission above ... More
Probing the very-high-energy gamma-ray spectral curvature in the blazar PG 1553+113 with the MAGIC telescopesAug 08 2014Apr 13 2015PG 1553+113 is a very-high-energy (VHE, $E>100\,\mathrm{GeV}$) $\gamma$-ray emitter classified as a BL Lac object. Its redshift is constrained by intergalactic absorption lines in the range $0.4<z<0.58$. The MAGIC telescopes have monitored the source's ... More
Contemporaneous observations of the radio galaxy NGC 1275 from radio to very high energy gamma-raysOct 31 2013Mar 05 2014The radio galaxy NGC 1275, recently identified as a very high energy (VHE, >100 GeV) gamma-ray emitter by MAGIC, is one of the few non-blazar AGN detected in the VHE regime. In order to better understand the origin of the gamma-ray emission and locate ... More
MAGIC contributions to the 32nd International Cosmic Ray ConferenceNov 03 2011Nov 08 2011Compilation of the papers contributed by the MAGIC collaboration to the 32nd International Cosmic Ray Conference (ICRC 2011), which took place between August 11 and 18, 2011 in Beijing, China. The papers are sorted in 6 categories: Overview and Highlight ... More
Observations of the Blazar 3C 66A with the MAGIC Telescopes in Stereoscopic ModeOct 04 2010Dec 17 2010We report new observations of the intermediate-frequency peaked BL Lacertae object 3C 66A with the MAGIC telescopes. The data sample we use were taken in 2009 December and 2010 January, and comprises 2.3 hr of good quality data in stereoscopic mode. In ... More
MAGIC observation of the GRB080430 afterglowApr 21 2010Apr 23 2010Context: 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 gamma-ray bursts during the prompt phase, i.e. the initial burst of high-energy ... More
MAGIC Collaboration: Contributions to the 31st International Cosmic Ray Conference (ICRC 2009)Jul 06 2009Jul 09 2009Index entry listing the contributed papers of the MAGIC collaboration to the 31th International Cosmic Ray Conference (ICRC 2009), July 7-15 2009, \L\'od\'z, Poland. The individual papers are sorted by subject: Overview and Highlight Papers; MAGIC-II ... More
Teraelectronvolt pulsed emission from the Crab pulsar detected by MAGICOct 23 2015Aims: To investigate the extension of the very-high-energy spectral tail of the Crab pulsar at energies above 400 GeV. Methods: We analyzed $\sim$320 hours of good quality data of Crab with the MAGIC telescope, obtained from February 2007 until April ... More
Discovery of very high energy gamma-ray emission from the blazar 1ES 0033+595 by the MAGIC telescopesOct 26 2014The number of known very high energy (VHE) blazars is $\sim\,50$, which is very small in comparison to the number of blazars detected in other frequencies. This situation is a handicap for population studies of blazars, which emit about half of their ... More
Detection of very high energy gamma-ray emission from the gravitationally-lensed blazar QSO B0218+357 with the MAGIC telescopesSep 05 2016Context. QSO B0218+357 is a gravitationally lensed blazar located at a redshift of 0.944. The gravitational lensing splits the emitted radiation into two components, spatially indistinguishable by gamma-ray instruments, but separated by a 10-12 day delay. ... More
Long-term multi-wavelength variability and correlation study of Markarian 421 from 2007 to 2009May 29 2016We study the multi-band variability and correlations of the TeV blazar Mrk 421 on year time scales, which can bring additional insight on the processes responsible for its broadband emission. We observed Mrk 421 in the very high energy (VHE) gamma-ray ... More
The broad-band properties of the intermediate synchrotron peaked BL Lac S2 0109+22 from radio to VHE gamma raysJul 05 2018The MAGIC telescopes observed S2 0109+22 in 2015 July during its flaring activity in high energy gamma rays observed by Fermi-LAT. We analyse the MAGIC data to characterise the very high energy (VHE) gamma-ray emission of S2 0109+22, which belongs to ... More
Discovery of TeV $γ$-ray emission from the neighbourhood of the supernova remnant G24.7+0.6 by MAGICDec 12 2018SNR G24.7+0.6 is a 9.5 kyrs radio and $\gamma$-ray supernova remnant evolving in a dense medium. In the GeV regime, SNR G24.7+0.6 (3FHL\,J1834.1--0706e/FGES\,J1834.1--0706) shows a hard spectral index ($\Gamma$$\sim$2) up to $200$\,GeV, which makes it ... More
A Fast Very High Energy $γ$-ray Flare from BL Lacertae during a Period of Multiwavelength activity in June 2015Jan 07 2019The mechanisms producing fast variability of the $\gamma$-ray emission in active galactic nuclei are under debate. The MAGIC telescopes detected a fast very high energy (VHE, E$>100$ GeV) $\gamma$-ray flare from BL Lacertae on 2015 June 15. The flare ... More
Detection of VHE γ-rays from HESS J0632+057 during the 2011 February X-ray outburst with the MAGIC TelescopesMar 13 2012The very high energy (VHE) \gamma-ray source HESS J0632+057 has recently been confirmed to be a \gamma-ray binary. The optical counterpart is the Be star MWC 148, and a compact object of unknown nature orbits it every ~321 d with a high eccentricity of ... More
Detection of very-high energy γ-ray emission from NGC 1275 by the MAGIC telescopesDec 16 2011Mar 05 2012We report on the detection of very-high energy (VHE, E>100 GeV) gamma-ray emission from NGC 1275, the central radio galaxy of the Perseus cluster of galaxies. The source has been detected by the MAGIC telescopes with a statistical significance of 6.6 ... More
Performance of the MAGIC stereo system obtained with Crab Nebula dataAug 06 2011Nov 17 2011MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes located in the Canary island of La Palma. Since autumn 2009 both telescopes have been working together in stereoscopic mode, providing a significant improvement with respect to the previous ... More
Phase-resolved energy spectra of the Crab Pulsar in the range of 50-400 GeV measured with the MAGIC TelescopesSep 28 2011Mar 01 2012We use 73 h of stereoscopic data taken with the MAGIC telescopes to investigate the very high-energy (VHE) gamma-ray emission of the Crab pulsar. Our data show a highly significant pulsed signal in the energy range from 50 to 400 GeV in both the main ... More
Searches for Dark Matter annihilation signatures in the Segue 1 satellite galaxy with the MAGIC-I telescopeMar 02 2011Jul 10 2011We report the results of the observation of the nearby satellite galaxy Segue 1 performed by the MAGIC-I ground-based gamma-ray telescope between November 2008 and March 2009 for a total of 43.2 hours. No significant gamma-ray emission was found above ... More