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A collection of MAGIC physics results

  • MAGIC detects very high energy gamma-rays from IC 310, a head-tail radio galaxy in the Perseus galaxy cluster This source was observed between November 2008 and February 2010. The Fermi satellite has also detected this galaxy. The source is detected by MAGIC at a high statistical significance in 20.6 hr of stereo data. The observed spectral energy distribution is flat with a differential spectral index of -2.0. The mean flux above 300 GeV, between October 2009 and February 2010, corresponds to 2.5% of Crab Nebula units. Only an upper limit, of 1.9% of Crab Nebula units above 300 GeV, had been obtained with the 2008 data. This, together with strong hints (>3sigma) of flares in the middle of October and November 2009, implies that the emission is variable. The MAGIC results favour a scenario with the very high energy emission originating from the inner jet close to the central engine. Originally issued as Astronomical Telegram #2510 on 25 March 2010. Read more in the article published as the Letter ApJL (723, L207).

  • MAGIC reports new observations of the intermediate-frequency peaked BL Lacertae object 3C 66A with the MAGIC telescopes in stereo mode. The data sample was taken in late 2009 and early 2010. In this period, we find a significant signal from the direction of the blazar 3C 66A. The new MAGIC stereoscopic system is shown to play an essential role for the separation between 3C 66A and the nearby radio galaxy 3C 66B, the sources being at a distance of only 6 arcminutes. Read more in the article submitted in Oct 2010

  • MAGIC reports upper limits for sources in the region around supernova remnant G65.1+0.6 . 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 both have a possible counterpart detected at about 35 TeV by the Milagro observatory. MAGIC found no significant emission around 1 TeV, from 25.5 hours of good quality data. This implies that the Milagro emission is either extended over a much larger area than our point spread function, or it must be peaked at energies beyond 1 TeV. Read more in the article, accepted for publication in ApJ.

  • MAGIC reports upper limits for Cygnus X-3. Cygnus X-3 is a microquasar consisting of an accreting compact object orbiting around a Wolf-Rayet star. It has been detected at radio frequencies and up to high-energy gamma rays (above 100 MeV). However, many models also predict a very high energy (VHE) emission (above hundreds of GeV) when the source displays relativistic persistent jets or transient ejections. Detecting such emission would improve the understanding of the jet physics. In observations of Cygnus X-3 over about 70 hours between early 2006 and mid-2009 in different X-ray/radio spectral states and also during a period of enhanced gamma-ray emission, MAGIC found no evidence for a VHE signal from the direction of the microquasar. Read more in the article, published in (ApJ 721, 843).

  • MAGIC discovers VHE gamma-ray emission from the high-frequency peaked BL Lac object B3 2247+381 MAGIC observations, triggered by an optical high-state of the source, reported by the Tuorla blazar monitoring program, revealed gamma-ray emission from the blazar B3 2247+381. This AGN, located at an intermediate distance of z=0.12 for its kind, was detected in E> 150 GeV gamma rays after a 9.3 hour-long observation performed on 2010 September 30th, October 1st, 2nd, 4th, 5th and 6th with both MAGIC telescopes working in stereoscopic mode. The preliminary analysis of the MAGIC data using standard cuts yields a detection of 64 gamma-rays, corresponding to a pre-trial statistical significance of 5 standard deviations. The observed flux is estimated to be ~2% of the Crab nebula flux above 150 GeV. MAGIC will continue to observe B3 2247+381 and encourages observations at other wavelengths. Issued as Astronomical Telegram #2910 on 7 October 2010.

  • MAGIC detects a huge VHE flare from the flat spectrum radio quasar 4C +21.35 In a recent Astronomer's Telegram, the MAGIC collaboration reports the detection of a gamma-ray outburst from the Flat Spectrum Radio Quasar 4C +21.35, located at a redshift of z=0.432. The observation was performed in stereoscopic mode during low intensity moon light using the two 17m diameter imaging Cherenkov telescopes on La Palma, Canary Islands, Spain. During only 0.5 hours on June 17, 2010, preliminary results indicate a significant gamma-ray signal of 120 excess events corresponding to >8 sigma level above the background. The integral flux for gamma-rays with energies above 100 GeV is estimated to be at >30% of the Crab nebula flux. MAGIC will continue to observe 4C +21.35. Issued as Astronomical Telegram #2684 on 19 June 2010.

  • MAGIC and VERITAS detect dramatic flaring of the giant radio galaxy M87 at an unprecedented flux level M87 has been observed in a coordinated effort in 2010 by the ground-based VHE gamma-ray observatories VERITAS and MAGIC; this effort is a continuation of the joint monitoring program which was initiated by VERITAS, MAGIC, and HESS in 2008. An increasing VHE gamma-ray flux level has been measured over several nights starting on 2010-04-05, reaching a historic high state of about 20% of the flux of the Crab Nebula during the observations on 2010-04-09. This flare follows a state of low average VHE flux from M87 over the past few months after a flare was reported by MAGIC earlier in 2010. Issued as Astronomical Telegram #2542 on 9 April 2010.

  • The Location of the Particle Acceleration in Messier 87 Revealed An alliance of the world-leading gamma-ray instruments MAGIC, VERITAS, and HESS with a team of radio astronomers working with the Very-Long Baseline Array, enabled an unprecendented 120-hour observational campaign on the giant radio galaxy M87 in spring 2008. Two major outbursts of gamma-ray emission could be observed, while simultaneous high resolution radio observations of the activity of this radio galaxy indicate a persistent increase of the radio flux from the innermost “core” of Messier 87, which is associated with the immediate vicinity of the central black hole. The combined observation pins down the location of activity during the gamma-ray outbursts and thus the site of the particle accelerator in M87. These results were published in Science (325, 444).

    More results from MAGIC (all published articles can be found here).

  • Confirmation of the AGN PKS 1424+240 as a gamma-ray emitter On June 24, 2009, the MAGIC collaboration reported the observation of very high energy gamma ray emission above 100GeV from the BL Lac object PKS 1424+240 as an astronomical telegram. The discoveries of high-energy and very high energy gamma ray emissions from this source were reported earlier this year by the Fermi Gamma-ray Telescope and on June 15 by the VERITAS collaboration. MAGIC observed PKS 1424+240 intermittently from May 2006 to June 2009. While observations in 2006 and 2007 show a marginal excess of events, but no clear evidence of gamma ray emission, recent observations in 2009 April to June reveal a possible state of high flux of the source. They result in an excess of 365 events corresponding to a statistical significance above 5 sigma, confirming the VERITAS signal. Issued as Astronomical Telegram #2098 on 24 Jun 2009.

  • MAGIC starts delimiting the parameter space for Dark Matter Dwarf Spheroidal Galaxies are believed to be the smallest and faintest astronomical objects whose dynamics is dominated by dark matter. They are found as satellites orbiting in the gravitational field of a larger host galaxy, e.g., our Milky Way. Usually, their member stars show large circular velocities and velocity dispersions, that combined with their modest spatial extent, can be interpreted by the presence of a large DM halo of the order of a million or more solar masses. Observations in early 2008 with MAGIC of one of these objects, named Willman-1, gave no significant gamma–ray signal above 100 GeV. We derived from the absence of signal upper limits on the integral flux above 100 GeV, and compared these limits with predictions from several established supersymmetric models. Future continued observations are likely to improve these limits by one order of magnitude and constrain, for the first time, the parameter space of these models.

    Published in ApJ 697, 1299, available also on http://www.arxiv.org/abs/0810.3561.

  • MAGIC detects a new gamma-ray source in the region of 3C 66A/B The MAGIC telescope observed the region around the distant blazar 3C 66A in August-December 2007 for more than 50 hours. The observations resulted in the discovery of a gamma-ray source (MAGIC J0223+430), at energies above 150 GeV, centered at celestial coordinates RA=2h23m12s and DEC=43deg0.7m, and coinciding with the nearby radio galaxy 3C 66B. Although the association of the signal with the blazar 3C 66A cannot be excluded (rest chances lying around 15% if including systematic uncertainties), 3C 66B is the more likely source of the emission. The measured energy spectrum has a relatively hard photon index of about 3 and extends up to 2 TeV. This gives additional support to 3C 66B as source: for 3C 66A a much softer energy spectrum would be expected. If the radio galaxy 3C 66B is confirmed as source of the observed very high energy (VHE) gamma rays, it would be the second radio galaxy (after M87) emitting VHE gamma rays, and would establish radio galaxies as a new class of VHE gamma-ray emitting sources. Published in ApJL 692, L29, available also on http://www.arxiv.org/abs/0810.4712.

  • MAGIC detects pulsed gamma-rays above 25 GeV from the Crab pulsar The Crab pulsar is a fast rotating, highly magnetized neutron star, that powers the famous Crab Nebula. At its core is a neutron star of a few solar masses, which is about 20 km in diameter. Its magnetic field is more than 1000 billion times stronger than that of the Earth. All Crab pulsar emission models predict that the energy spectrum of the pulsed emission drops off sharply somewhere between a few GeV and a few tens of GeV. The MAGIC measurements reveal that the drop-off in the emitted radiation occurs at relatively high energies, which indicates that the emission must occur far out in the pulsar's magnetosphere. All models in which the emitting region is located close to the pulsar surface (e.g., the so-called polar cap model) are ruled out.

    Originally issued Astronomical Telegram #1491, published in Science Magazine 322 (2008) 1221.

  • MAGIC discovers the most distant very-high energy gamma-ray emission from an accreting supermassive black hole. How transparent is the Universe? The MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescope has detected emission of very high energy gamma rays from the active nucleus of the 3C279 galaxy. This quasar is distant more than five billion light years (roughly half the radius of the Universe) from the Earth, more than twice the distance of objects previously observed with this kind of radiation. The detection of VHE gamma-ray emission from a source at such a distance as 3C279 constrains current theories about the density of the Extragalactic Background Light. The Universe appears more transparent at cosmological distances than believed, precluding significant contributions from light other than from sources observed by current optical and infrared telescopes.

    Original Publication: MAGIC Collaboration, Science 320 (2008) 1752.

  • MAGIC detects fast flux variability during an extended flare of M87 During a monitoring program of the close-by, giant radio galaxy M87, the MAGIC telescope detected a rapid flare in VHE γ-rays in early 2008. The flux was found to be variable above 350 GeV on a timescale as short as 1 day on a significance level of 5.6 sigma. The highest measured flux reached 15% of the Crab nebula flux. We observed a rather complex flare structure with several substantial changes of the flux level during the total 13-day observing period. The flux at lower energies (150 GeV to 350 GeV), instead, is compatible with being constant. The energy spectrum can be described by a power law with a photon index of 2.30±0.11stat±0.20syst. The observed day-scale flux variability at VHE prefers the M87 core as source of the emission and implies that either the emission region is very compact (just few Schwarzschild radii) or the Doppler factor of the emitting blob is rather large in case of a non-expanding emission region.

    Original publication: Astrophys. J. 685 (2008) L23

  • MAGIC discovers VHE gamma ray emission from the blazar S50716+714 The MAGIC collaboration reports the detection of the blazar S50716+714 (redshift unknown) in very high energy gamma-rays, using the 17m diameter MAGIC Cherenkov telescope on La Palma (27.8 N, 17.8 W, 2200 m asl). The observations were performed from April 22 to 24, 2008 and were triggered by the KVA Telescope due to the high optical state of the object. The source is also in a high X-ray state as reported by Swift (Giommi et al., ATel #1495). A preliminary analysis of MAGIC data (3 nights, 2.6 hours in total) revealed a signal of 6.8 sigma corresponding to a flux of F (above 400GeV) = 10-11 ph/cm2/s. MAGIC will continue the observation of S50716+714. Multi-frequency observations are strongly encouraged. Published as Astronomical Telegram #1500

  • Multi-wavelength (radio, X-ray and gamma-ray) observations of the gamma-ray binary LS I +61 303 A multiwavelength view of the gamma-ray binary LS I +61 303: After discovering the variable VHE emission from the binary system LS I +61 303, we have re-observed this source together with the radio interferometers MERLIN, e-EVN and VLBA, and the X-ray telescope Chandra. The observations were carried out during October and November 2006 and have unveiled different properties of the system that will help elucidate the origin of the non-thermal emission (jet or pulsar wind), currently under a passionate debate. Comparing our radio images at different angular scales with those obtained in the past, we have found a high level of periodicity and stability of the processes behind the radio emission at the milliarcsecond (mas) scale and discarded the presence of a persistent, large scale (~100 mas) jet. Also, our results point to the existence of one population of particles producing the radio emission and a different one producing the X-ray and TeV emissions. Furthermore, we have produced, for the first time, a quasi-simultaneous energy spectrum including radio, X-ray and TeV bands, which will serve as input for the theoretical models aiming at describing the nature of this peculiar object.

    Original publication: J. Albert et al., Astrophys. J. 684 (2008)1351

  • Draco as signal for Dark Matter: The nearby dwarf spheroidal galaxy Draco with its high mass to light ratio is one of the most auspicious targets for indirect dark matter searches. Annihilation of hypothetical dark matter particles can result in high-energy gamma-rays, e.g. from neutralino annihilation in the supersymmetric framework. With the MAGIC telescope, a search for a possible dark matter signal originating from Draco was performed during 2007. The analysis of the data results in a flux upper limit of 1.1x10^-11 photons cm^-2 sec^-1 for photon energies above 140 GeV, assuming a point-like source. A comparison with predictions from supersymmetric models shows that the observations do not constrain the phase parameter space, but a very high flux enhancement can be ruled out.

    Original publication: J. Albert et al., Astrophys. J. 679 (2008)428

  • Unidentified source near Cygnus X-3: By the turn of the millenium, Cherenkov telescopes had only detected a handful of sources; the serendipitious discovery of a source not far from Cygnus X-3 thus came as a major surprise. Cyg X-3 is a well-known X-ray binary and had been claimed to emit at very high energies in the eighties. Newly built detectors like the HEGRA system of telescopes at La Palma, however, had failed to confirm this high-energy emission, even after hundreds of hours of observations. This long exposure, however, eventually paid off when a weak signal was detected half a degree away from Cyg X-3. The source, dubbed TeV2032, did not vary over a period of four years, was slightly extended (some 6 arcminutes), and had no clear counterpart at other wavelengths, i.e. there was no other source at the same position of the sky in infrared, X-ray, optical or radio waves. Such observations could convincingly explain the emission at very high energy gamma rays. Over the years the situation has remained puzzling as more and more sensitive observations of the same region of the sky have yielded no new information. Enter MAGIC. We have spent a total about 100 hours looking at the position reported by HEGRA, in observations which spread over a period a 3 years. MAGIC is more sensitive than HEGRA, but this source is very weak indeed! At the end of this long study, the longest to date with MAGIC for a single source, we have managed to detect TeV2032. It is still there, and it's still as weak as reported by HEGRA, so it looks like it is not very variable. We can also confirm that it is extended, with an elongated shape, although with only some 300 photons colllected (after 100 hours of observations!) the shape remains uncertain: see the two-dimensional 'sky plot'. What exactly is this object? We cannot tell, it remains a mysterious "dark source".

    Original publication: J.Albert et al., Astrophysics J. 675 (2008) L25

  • 3C279, the record in distance: MAGIC recently detected the oldest Very High Energy gamma-ray photons observed up to date. The present record holder is the very distant blazar 3C 279, at a redshift z = 0.536 (corresponding to a light travel time of 5.3 billion years!), at more than twice the distance of previously found sources of VHE gamma-rays. The signal was strong only for a short period, during one night (with a weaker signal the night before), and extended over the energy range from 80 to more than 300 GeV. Its strength (at 100 GeV) was of the same intensity level as the Crab. The detection of VHE radiation from such a distant source permits hope that future exposure in the energy range below 100 GeV will contribute substantially to the study of blazar emission mechanisms. In addition, determination of the spectral features of the distant sources, especially above 100 GeV, will allow understanding more about absorption due to the extragalactic background light.

    Original publication: J.Albert et al., Science 320 (2008) 1752

  • Another very distant source: The second most distant source detected is the blazar 1ES 1011+496, at a redshift z = 0.212 (still nearly three billion lightyears!). The observations of this source were triggered by an optical outburst in March 2007. The same blazar had been observed previously by MAGIC, in a lower optical state, and then yielded only a hint of a signal. Observing in early 2007 for 18.7 hours, a significant excess of gammas over background was found, corresponding to an integrated flux above 200GeV of (1.58±0.32)x10^-11 photons/cm^2/sec. This observation, together with the fact that 1ES1011+496 is already the second blazar discovered during an optical outburst, seems to indicate that the VHE-emission of blazars is enhanced during high states at optical wavelengths.

    Original publication: J.Albert et al., Astrophys. J. 667 (2007) L21

  • Quantum Gravity constraints from a blazar flare?: Data from a well known TeV blazar, Mkn501, were re-analyzed for energy-dependent differences in arrival time. This source showed flux variations by an order of magnitude, and short-term fluctuations (flares) were observed in the original analysis, with flux-doubling times as low as two minutes during two nights. These flares were now subjected to a detailed analysis, using advanced statistical methods and all individual gamma-rays. The results rather confirmed the previous analysis, permitting to speculate about a possible sign of profound consequence: some models of quantum gravity predict an effect of energy-dependent arrival time, exactly the kind that was observed.

    Original publication: J.Albert et al., Phys. Lett. B 668 (2008) 253

  • A scan of high-frequency peaked BL Lac objects: All but two (M87, BL Lac) extragalactic sources detected so far at VHE energies belong to the so-called HBL class, i.e. high-frequency peaked BL Lac objects. With the MAGIC telescope, the collaboration has performed a systematic scan of X-ray blazars in the Northern hemisphere, from December 2004 to March 2006. The search was limited to X-ray bright sources at limited redshift (z<0.3). 14 sources were observed. Of these, 1ES 1218+304 was seen for the first time at very high energies (published in ApJ 642, L119), and observations of 1ES 2344+514 resulted in a strong detection in a low flux state (published in ApJ 662, 892). A signal for the large-redshift (z=0.212) source 1ES 1011+496 was also seen (described separately above). In addition, the known bright TeV blazars Mrk 421 and Mrk 501 were observed (see below). For the remaining sources, MAGIC published upper limits on the integral flux above at 200GeV. We compare the absorption-corrected γ-ray luminosities at 200GeV with simultaneous optical, archival X-ray, and radio luminosities, to constrain the statistical properties of the sample.

    Original publication of the systematic search for HBLs: J.Albert et al., Astrophysics J. 681 (2008) 944

  • A short-lived signal from Cygnus X-1: MAGIC reports a possible detection of VHE gamma-rays over a short period, in the direction of the black hole X-ray binary Cygnus X-1. Observations over a total of 40 hours during 26 nights between June and November 2006 gave no positive result for steady radiation, and upper limits to the integral flux above 150 GeV can be set around 1 - 2% of the Crab flux. We obtained, however, evidence of gamma-ray signals in a search for faster-varying signals. An excess with a significance of 4.9 sigma (4.1 sigma after trial correction) was found for a 79-minute period between MJD 54002.928 and 54002.987. This excess is compatible with a point-like source at the position of Cygnus X-1, and excludes the nearby radio nebula powered by its relativistic jet. The differential energy spectrum is well fitted by an unbroken power law with an index of -3.2+-0.6. This is the first experimental evidence of VHE emission from a stellar-mass black hole, and therefore from a confirmed accreting X-ray binary.

    Original publication: J.Albert et al., Astrophys. J. 665 (2007) L51

  • Very high energy gammas from BL Lacertae: For the first time, a significant TeV gamma-ray signal of BL Lacertae could be detected. BL Lacertae is the eponym of the BL Lac-type active galactic nuclei. This is the first low-peaked blazar to be observed in the TeV energy band. See the BLL sky map with the observed excess events, and the observed steep spectrum, with an index of -3.64.

    Original publication: J.Albert et al., Astrophys. J. 666 (2007) L17

  • A new source detected: MAGIC reported the detection of a new source of very high energy (> 100GeV) gamma-ray emission located close to the Galactic Plane, spatially coincident with SNR IC443. It has been named MAGIC J0616+225. The observations were carried out in December 2005 - January 2006, and in December 2006 - January 2007. They result in a signal with a statistical significance of 5.7 sigma in the 2006/7 data, and a measured differential gamma-ray flux consistent with a power law with an index of -3.1. The publication contains a discussion of the multiwavelength emission and the molecular environment found in the region of IC443.

    Original publication: J.Albert et al., Astrophys. J. 664 (2007) L87

  • The Supernova remnant Cassiopeia A: MAGIC reported a signal of very high energy (VHE) gamma-ray emission from the supernova remnant Cassiopeia A, observed for 47 hours between July 2006 and January 2007. The source was detected above an energy of 250 GeV with a significance of 5.3 sigma and a photon flux above 1 TeV of (7.3±0.7(stat)±2.2(sys))x10^-13 photons/cm^2/sec. The photon spectrum is compatible with a power law with a photon index 2.3±0.2(stat)±0.2(sys). The source is point-like within the angular resolution of the telescope.

    Original publication: J.Albert et al., Astronomy & Astrophys. 474 (2007) 937

    This observation was partially made under moderate Moon illumination, a novel achievement for Imaging Atmospheric Cherenkov Telescopes; the available observation time thus can be substantially extended. Details are under publication separately (available as astro-ph/0702475).

  • Markarian 501: Mkn 501 is a close TeV blazar, first detected by Whipple in 1996. MAGIC observations during 55 h showed the source in a comparatively low state for most of the time, but also caught two episodes of fast and intense flux variability (flares), with doubling times as low as 2 minutes (see the light curves for 30 June and 9 July 2005, in 2-minute bins). Changes in the spectral slope correlated with the flux level were observed for the first time on such short time scales, as can be seen in the spectral energy distributions (SEDs) for those two days, given separately for the short flaring period (red) and the immediately preceding 20 minutes. The SED has a maximum around 300-400 GeV, which may be interpreted as an indication of the synchrotron self-Compton (SSC) electron acceleration model.

    There is also an hint of a possible shift of arrival time with energy (see the energy-dependent light curves for 9 July, in 4-minute time bins), with the more energetic photons arriving later. If confirmed in the future, this effect may be interpreted as a stringent limit on the acceleration models, potentially even as a limit on the mass scale of quantum gravity (if synchronous production is assumed), for which some models predict such shifts in time.

    Original publication: J.Albert et al., Astrophys. J. (669, 862)

  • The Crab nebula: The Crab nebula, much used as a constant 'calibration' source, was extensively measured also by MAGIC, between 60 GeV and 9 TeV. This is the most detailed study of this source at such energies, low for a Cherenkov telescope. A clear curvature was detected, and the Inverse Compton maximum in the Spectral Energy Distribution could be determined to be at 77 +- 47 GeV. No pulsed emission could be observed, indicating a cutoff energy of <27 GeV.

    Original publication: J.Albert et al., Astrophys. J. 674 (2007) 1037

  • Pulsar observation: The pulsar PSR B1951+32 was observed, and upper limits both for steady and pulsed emission could be determined and compared to models, constraining the cutoff energy of the pulsar to <32GeV.

    Original publication: J.Albert et al., Astrophys. J. 669 (2007) 1143

  • 1ES2344: The BL Lac object 1ES2344+514 was the third of its kind to be detected in VHE gamma-rays. On December 20, 1996, the Whipple collaboration registered a gamma-ray flare of 0.63 Crab units coming from this object at a significance level of 5.8 sigma. Since then, only marginal detections of 1ES2344+514 were reported by different IACTs.

    In the first year of operation MAGIC has started a program to study the properties of the low-emission state of BL Lacs. 1ES2344+514 has been observed from August 2005 until January 2006. In a total of 27 days, 23.1 h exposure were accumulated. 1ES2344+514 was found at a flux level of about 11% of Crab with a high significance of 11 sigma. For the first time, a lightcurve on day-to-day basis during a rather low state of activity could be inferred. Also a differential energy spectrum of the object could be inferred, which is softer than the flare spectrum reported by the Whipple collaboration. In the past, most of the VHE gamma-ray emitting BL Lacs were discovered during phases of high activity, biasing our current observational record towards high emission states. It still remains an open question whether these sources are only temporarily active and are completely inactive between times of flaring, or if there also exists a state of low but continuous gamma-ray emission. With MAGIC, the low level emission of blazars can now be accessed within only a few hours of observations, enabling studies of the VHE gamma-ray variability properties of these objects of over a significant dynamical range. Thus, 1ES2344+514 adds to the small group of blazars for which such studies are now possible on diurnal basis.

    Original publication: J.Albert et al., Astrophys. J. 662 (2007) 892

  • Periodicity in VHE gamma-rays: The X-ray binary LSI +61 303 was observed in 2006. For the first time, a periodically variable VHE (very high energy) gamma emitter was seen. Look at two sky maps showing the observed gamma-ray excess events at two different orbital phases of the underlying binary system. Yellow crosses correspond to the position of the optical source, the green contours indicate EGRET sources at lower gamma energy. The interest of the observation lies in the fact that the source is visible only in a short window of phase. Also, the maximum does not coincide with the maximum observed in periodic radio outbursts. You can also watch an animated explanation of the LSI +61 303 observation (ppt file: ask for slide show).

    Original publication: J.Albert et al., Science 312 (2006) 1771

  • Markarian 180: Mkn 180 had an optical outburst in March 2006, which triggered observations with the MAGIC telescope in the GeV/TeV band. The result was the first detection of VHE gamma-ray emission from this source.

    Original publication: J.Albert et al., Astrophys. J. 648 (2006) L105

  • Pulsars: Three millisecond pulsars were observed (PSR J0218+4232, PSR B1951+31 and PSR B1957+20). Upper limits for VHE have been reported (see astro-ph/0702077).

  • Gamma-ray Bursts: MAGIC is constructed light-weight to permit fast slewing, and regularly observes potential GRB sources after being alerted by satellites (mostly by Swift). So far (early 2007), nine sources were followed, with typical slewing times between 30 and 60 seconds. No significant VHE radiation was observed, possibly due to large redshifts of these sources (which results in absorption due to the extragalactic background light). See the detailed table of observed GRBs.

    Original publication: J.Albert et al., Astrophys. J. 667 (2007) 358


  • This page was created by Robert Wagner. Last modification 04.08.2011 by Rudolf Bock.
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