PoS(ICRC2015)732 , A. http://pos.sissa.it/ e , D. Hadasch d for the MAGIC Collaboration g 303, MWC 656, Cygnus X-1 and SN 2014J. , C. Fruck ◦ c and R. Zanin g , D. F. Torres b ∗ , P. Munar-Adrover f , a 303 (7 and 8 years, respectively). The former is one of the brightest X-ray sources ◦ , E. de Oña Wilhelmi a [email protected] We present the results of those observations,LS including I long-term +61 monitoring of Cygnusand X-1 and best studied microquasars acrosssignal a was broad studied by range MAGIC of within wavelengths, aobject, multiwavelength whose MWC scenario. steady 656, The and are latest variable results also ofbinary shown an system in unique detected this that presentation. is This composedobservations source of of a is SN black the 2014J, hole first the and high-massobservation nearest a X-ray gave Type Be a Ia remarkable star. opportunity SN Finally, to we of study report the important on last features the of 40 these years. powerful events. Its proximity and early Galactic transients, X-ray and gamma-ray binariesceleration. provide a proper This environment leads for to particleregime. ac- the MAGIC has production carried of outjects gamma deep of observations rays which of we with highlight different 4 energies transient of and them reaching here: variable the LS stellar I GeV-TeV ob- +61 Speaker. ∗ Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. now at Laboratoire AIM, Service d’Astrophysique, DSM\IRFU, CEA\Saclay FR-91191 Max-Planck-Institut für Physik, D-80805 (München, Germany) Universitat de Barcelona, ICC, IEEC-UB, E-08028 (Barcelona, Spain) IFAE, Campus UAB, E-08193 (Bellaterra, Spain) Institute of Space Sciences, E-08193 (Barcelona, Spain) Institute for Cosmic Ray Research, University of Tokyo, 277-8582 (Chiba, Japan) ICREA and Institute of Space Sciences, E-08193 (Barcelona, Spain) c f The 34th International Cosmic Ray Conference, 30 July- 6 August, 2015 The Hague, The Netherlands d e Gif-sur-Yvette (Cedex, France) g a b c

López-Oramas IFAE, Campus UAB, E-08193 Bellaterra, Spain E-mail: O. Blanch A. Fernández-Barral VHE gamma-ray observations of transient and variable stellar objects with the MAGIC Telescopes PoS(ICRC2015)732 51 0.03% ± W, 2225 m ◦ A. Fernández-Barral N, 17.8 ◦ 0.6c) one-sided radio-emitting jet (8). ≥ 2 O9.7 Iab supergiant companion star (6), follows a

0.2 kpc (4). The binary system, composed of a black ± . When this happens, the electron-degenerate core can not

(5) and a 17-31 M

15 M ∼ 303. ◦ Nevertheless, X-ray binaries are not the only variable galactic events expected to emit in the The MAGIC collaboration has developed a large-scale observational program to study gamma- All the observations presented in this proceeding were performed with the MAGIC telescopes, Cygnus X-1 is one of the most studied and brightest HMXBs (3) of our galaxy, located in VHE range. Other transientgamma-ray events, emission. like supernovae In (SNe), this showIa a proceeding, SN proper we in environment present for the theorigin VHE last results is for four also SN decades. a 2014J, binarythe the system Chandrasekhar Type where nearest mass Ia limit one Type SNe of of 1.4M are the extremely members, a luminous carbon-oxygen stellar white explosions dwarf, whose reaches ray binaries and to search forsince very the high first energy telescope (VHE, E started > takingpact 100 data object, GeV) in which emission 2004. can from be X-ray X-ray a binary binaries These neutron systems systems star can are (NS) be composed or split of into a a High black(LMXBs) com- Mass according hole X-ray to (BH), Binaries the that (HMXBs) type orbits and of a Low thesystems Mass stellar stellar X-ray contain companion. companion. Binaries a In this young work, star wefrom focus of the on spectral HMXBs. companion type star These through O anmore or accretion B energy disk in and or a the strong compact gamma-ray stellarproceeding wind. object range we that than X-ray will accretes binaries at show that material X-ray emit theLS are I results classified +61 of as 3 gamma-ray binaries. variable binary In systems: this Cygnus X-1, MWC 656 and a stereoscopic system of two 17located m in diameter El Imaging Roque Atmospheric de Cherenkov los Telescopes Muchachos (IACTs) on the Canary island of La Palma (28.8 VHE gamma-ray observations of transient and variable stellar objects with MAGIC 1. Introduction support the increase in gravitational pressure,erg so takes a place. thermonuclear After explosion these of powerful approximately events 10 no compact remnant is expected. the Cygnus region at a distance of 2.15 a.s.l.). MAGIC was composed of juststructed. one Between summer stand-alone 2011 IACT and until 2012 both 2009trigger telescopes when and underwent MAGIC a readout II major system upgrade was as involving con- the wellan as integral the sensitivity MAGIC (E>220 I GeV) camera, forof enhancing sources the the with performance a Crab to Crab Nebula achieve Nebula-like fluxstand-alone spectrum mode of in (only 0.66 50 one telescope hours operating) ofhours the (2). observation sensitivity above in 280 stereoscopic GeV is observational 1.6% mode Crab in (1). 50 For 2. Cygnus X-1 The X-ray studies (E< 20keV)system revealed with that the the two system distinguishableX-1 behaves soft for as and 40 a typical hard hours black-hole state betweenI). transient No June (9). significant and excess In November for 2006, with steady MAGIC the or observed stand-alone variable Cygnus emission MAGIC was telescope detected, (MAGIC except for one day. During hole with mass circular orbit of 5.6 days (7).a It highly has collimated been (opening firmly angle established <2 as deg) a microquasar relativistic after (v the detection of PoS(ICRC2015)732 · 0 . ) = 0.10 =0.2 φ ± =2.5. The dAdtdE Γ =0.01 ( / per . The system is φ

dN 1 hour on June 4th A. Fernández-Barral ∼ ) was computed using . Any potential steady 1 σ 3.3 hours in stereoscopic mode in the ∼ . After this hint of activity in the gamma-ray 1 − 3 0.04 days (13) with the periastron at TeV 1 ± − s 2 − cm 6 . 0 ± 80 hours (after data quality cuts) at a zenith range between 6 and 2 . 3 ∼ − ) 0.6 kpc (12) and from observed optical photometric modulation, the pe- ± after trials was observed, where the significance ( TeV 1 =0.0-0.1, just after the periastron. During this last observation epoch, XMM- σ / φ E ( 12 at 95% confidence level (CL) above 300 GeV with a photon index of − 1 10 − · s 2 ) 6 − observed the source immediately following MAGIC observations for . . 0 =1.0. On June 2013, the system was observed for cm MWC 656 is currently the only detected binary composed of a Be star and a BH (12), where ± φ 12 3 − =0.8). No specific information in the X-ray energy range was available for the period of 2012. . 2 φ located at a distance of 2.6 (12). On July 2010, AGILEtriggered detected MAGIC a observations gamma-ray (14). flare locally coincidentIn with order the to evaluate system, if which thetwo source campaigns emits in in the a VHE zenith gamma-raygood range regime, quality between MAGIC data observed 22 it in and during stand-alone 51 mode deg. were From taken May with to MAGIC June II 2012, between 21.3 orbital hours phases of VHE emission is fardetection away can from no a be detectable ruledAGILE level out with in any the IACT, case although of the a possibility flare of occurring a at the level of the flux detected by riod of the orbit was determined to be 60.37 the authors conclude that this source is a HMXB with a measured BH of 3.8-6.9 M 3. MWC 656 regime, MAGIC has carried out observationsThe from source 2007 to was 2014 observed focusing for on50 the deg hard during state. 5 observationalone campaigns in mode 5 (with years. MAGICwobble-mode The I) first (11). between campaign June The was performed and secondmode in November one on a was 2007 July stand- 2008. carried with out The theand campaign using tracking also from only mode stereo June MAGIC to mode called I October underboth in 2009, wobble-mode. telescopes. the presents Finally, data on-off On on taken September tracking September in 2014, 2011,previous stand-alone the campaign Cygnus source but X-1 was during observed was its with soft observedWe same state. performed with conditions searches as for the VHE emissionfunction on of daily basis the (due different to X-ray theto states variability significant and of excess for the of the source), photons full as from data a the sample. source position. None of the conditions yielded and orbital phase range ( The system did not showbasis significant VHE emission. gamma-ray excess The in10 any integral epoch, flux either upper steady ordata limit distributed daily along (UL) a for phase binning theThe width of computed entire 0.1 differential data was flux also sample analyzed ULsTeV with between was at no 245 95% significant set CL, GeV emission. at with (energy five threshold 2 bins of per the decade analysis) of and energy, are 6.3 shown in Figure Newton VHE gamma-ray observations of transient and variable stellar objects with MAGIC the night of Septemberof 24, approximately 4.1 which was concurrent with the hard( state of the source, an excess equation 17 of (10). The spectrum for that day followed a power-law defined as PoS(ICRC2015)732 AGILE ) bursts 1 0.03 and − ± ergs 0.6-0.7 (next to =0.081) once by 37 ∼ φ A. Fernández-Barral φ 12 10 -LAT with periodic out- 10 10 0.8-1.0 has also been reported Fermi ∼ 8 φ 10 6 10 4 10 E [eV] 4 2 10 0 10 , 2010 July , 3.5 years 2 , 2010 July − 10 4 Radio EVN, 2011 January-February X-ray, 2013 June AGILE Fermi/LAT Fermi/LAT MAGIC, 2013 June − 10 8 days, detected in the radio band). This superorbital variability was 6 ± -LAT data taken simultaneously with the AGILE observations (17). − 10 39 37 35 33 31 29 27 25

10 10 10 10 10 10 10 10

Fermi

− 0.3-0.45. In the VHE regime, the first detection was performed by MAGIC (20), Fd r s erg [ dF/dE E

] 303 was proposed to be the first binary system that holds a magnetar (27), after

2 1 =2.5. The spectral energy distribution (SED) includes EVN radio ULs (15), the ◦ ∼ Γ 4% Crab flux) (22) and only detected close to the periastron ( 303 is a member of the small group of gamma-ray binaries that has been detected 303 0.03. The source was detected in HE gamma-ray by φ ◦ ◦ ∼ ± Differential ULs from MWC 656 obtained by MAGIC during the 2013 campaign, assuming a detection of two very short-timescale (< 0.1 s) highly-luminous (> 10 =0.23 LS I +61 per Swift φ 4. LS I +61 energy flux (16) and in a very broad wavelength range,a from Be radio up star to (spectral VHE type gamma-rays.(NS B0Ve, or The (18)) BH). system with The is a orbit composed circumstellar that of a the disk period compact and of object an performs 26.4960(28) unidentified presents daysto compact an obtained eccentricity object by of radio 0.54 analysisbursts (19). around The periastron phaseand has confirmed been later set on bythe VERITAS (21), apastron). whose Sporadic periodic emission peak with isby significant flux detected MAGIC at at ( phases VERITAS (23). The non-thermalorbit-to-orbit component base of the (1667 emission presents periodical outbursts in an Figure 1: also found in HE (24).is Despite not the clearly multiwavelength defined information, yet.the the nature observed There of extended are its jet-like three VHEthe radio-emitting emission proposed rotating structure scenarios: tail-like (25), elongated the the morphology microquasarfinally, pulsar of LS scenario, wind overall I due size scenario, +61 to 5-10 thanks masthe to obtained by VLBA (26) and photon index of VHE gamma-ray observations of transient and variable stellar objects with MAGIC from the source direction. Inclose this to flip-flop the magnetar periastron model due theVHE to gamma-ray pulsar the emission, magnetosphere while circumstellar is in disk disrupted phases ofto next the TeV to due the Be apastron to star the the (propeller particlesimplies rotational-powered regime) can a pulsar suppressing be higher accelerated (ejector circumstellar up regime). disk of A the higher star mass-loss and vice rate versa, of so the that star the propeller regime can take PoS(ICRC2015)732 · ± 90 303 line . ◦ stat α 8 . H line and 0 α ± H . This shows 70 2 . − 3 ( 10 A. Fernández-Barral · 7 . shows the data folded 2 =0.8-1.0 where sporadic TeV φ 4.5 year radio modulation seen in other wave- 0.04 in general. Figure ∼ ± 5 =0.55-0.75, from August 2010 to September 2014 φ with 95% CL. Taking into account the detection of 1 − s 2 − cm 12 − 10 · 50 . , we have also established an integral UL for this energy range at 3 1 − s . Assuming a sinusoidal signal, the fit probability reaches 8%. The data have 2 12 − − 303 presents yearly variability in the peak of the periodical outburst, spectral stud- ◦ cm 10 13 · − 5 303 and that it is compatible with the . ◦ 10 · ) On January 21st, 2014, the UCL Observatory detected SN 2014J at a distance of 3.6 Mpc in syst 7 . the starburst galaxy M82,3.5m which telescope was as classified a Type by IaSN SN. the Type The Dual Ia proximity Imaging of in this Spectrograph thecampaign event on last gave was SN carried the 42 2014J out. ARC years. the titleSN Due of 2014J the to was nearest its observed proximity, withditions a MAGIC and from multiwavelength on January follow-up February 27th observation 1st to anddata 29th 2nd were under under taken dark-night at moderate conditions. medium moonlight zenith In con- No angles, total, between signal 6 40 hours from and of 52 the good-quality 300 deg. direction GeV of was the set source to was 1 detected. The integral UL for energies above in the superorbital period.value The of probability 4 that the data describes a constantthat flux the is intensity a distribution cannot negligible dient be described is only needed. with It aLS can high I be and a concluded +61 low that state, therelenghts. but is that No a a (anti-)correlation superorbital gra- has signatureemission. been in found the Nevertheless, between TeV the emission the relation of between mass-lossdenied these rate since two of the parameters the can timescale star not ofrespectively. and be the the either observations TeV confirmed in or optical and TeV differs from minutes5. to hours, SN 2014J furthermore been fitted by a step function, resulting in a fit probability of 4 the host galaxy, M82, reported by VERITAS (28) for energies above 700 GeV, VHE gamma-ray observations of transient and variable stellar objects with MAGIC place even close to the apastron. In order to confirm the superorbitalwhen variability in the the periodical VHE regime, VHE MAGIC outburst observedin LS happens, stereoscopic I +61 mode (except Januaryformed). 2012, Archival when MAGIC mono data observations (frompublished with VERITAS 2006 data MAGIC have to also II 2010, been were giving usedthe per- to rise pulsar study to wind this scenario, a variability. and The total more studying 8-year specifically of for the campaign) the flip-flop viability (anti-)correlation and magnetar of of model, isthat the carried goal TeV out emission MAGIC search- performed and simultaneous the(also observations located mass-loss in with rate El the of Roque optical de the telescope los Be Muchachos) LIVERPOOL star. during orbital To phases achieve 0 emission has previously been detected. Theemission, mass-loss thus rate of the the Pearson star correlation isthe coefficient correlated equivalent and with width the the (EW), full probabilities width of half the maximum correlation (FWHM) between and the velocity of the the TeV flux were calculated. Since LS I +61 ies to find evidence forusing the various mechanism entire data of set gamma-raylevel yield and production a studies were spectral using carried index compatible samples out. with based 2.43 Studies on superorbital, orbital phase and flux PoS(ICRC2015)732 A. Fernández-Barral 6 25 hours of good-quality data available for this source. ∼ . 3 at the same CL. Daily flux ULs for energies above 300 and 700 GeV were also 1 − s 303 observations revealed that the source displays a superorbital variability consistent 2 Peak flux emitted for each orbital period, for orbital phases 0.5-0.75, in terms of the superorbital ◦ − cm MAGIC has performed several observation campaigns on transient and variable stellar ob- We would like to thank the Instituto de Astrofísica de Canarias for the excellent working con- 12 − jects. Cygnus X-1 was observed froma 2007 detection to was 2014 expected focusing according on to thegamma the hard hint rays X-ray obtained spectral has previously state been by when MAGIC.sage, found No close in excess of to any VHE the period. reportedabove AGILE MWC 300 emission, 656 GeV with was have no observed been significant during excess. set the for Integral periastron the ULs pas- atwith the energies radio and HE results.between In the order to mass-loss probe rate the of flip-flopthough the magnetar no model, Be clear the correlation companion (anti-)correlation has star beenthis and found. work. the Observations No of TeV detection SN emission in 2014J has the have been VHE also regime been studied, by presented al- MAGIC in can be reported. 7. Acknowledgments ditions at the Observatorio del RoqueBMBF de and los MPG, Muchachos in the Lathe Italian Palma. Spanish INFN, The MINECO the support is of Swiss gratefully the National German acknowledged. Fund This SNF, and work was the also ERDF supported funds by under the CPAN 6. Conclusions LS I +61 Figure 2: phase as defined by radio (19).in this MAGIC analysis. (magenta dots) The and fit to VERITAS (blue(solid a sinusoidal squares) blue (solid points line) red have line), been are to used also agray step solid represented. function line (solid marks The green the line) gray zero and dashed with level, a just line10 constant as represents a 10% reference. of the Crabcomputed Nebula and are flux. shown in The Figure VHE gamma-ray observations of transient and variable stellar objects with MAGIC PoS(ICRC2015)732 (2009) (2011) 84, , (Sept., 2014) 30 742 A. Fernández-Barral ]. ArXiv e-prints , Astrophys.J. Astropart.Phys. (2005) 851–859, , , (2009) 1895–1905, 358 701 (1965) 394–398. 147 astro-ph/9906365 7 The major upgrade of the MAGIC telescopes, Part Astrophys.J. Science , , Improving the performance of the single-dish ]. 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