OBSERVATIONS OF THE CRAB PULSAR BETWEEN 25 AND 100 GeV WITH THE MAGIC I TELESCOPE

Aleksić, J.; Álvarez, Ezequiel; Antonelli, L. A.; Antoranz, P.; Asensio, M.; Backes, Michael; Barrio, J. A.; Bastieri, D.; González, J. Becerra; Bednarek, W.; Berdyugin, A.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Böck, R.; Boller, A.; Bonnoli, G.; Tridon, D. Borla; Braun, I.; Bretz, T.; Cañellas, A.; Carmona, E.; Carosi, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Cossio, L.; Covino, S.; Dazzi, F.; Angelis, A. De; Caneva, G. De; Pozo, E. De Cea del; Lotto, B. De; Mendez, C. Delgado; Ortega, A. Diago; Doert, M.; Domínguez, A.; Prester, D. Dominis; Dorner, D.; Doro, M.; Eisenacher, D.; Elsäesser, D.; Ferenc, D.; Fonseca, M. V.; Font, L.; Fruck, C.; López, R. J. García; Garczarczyk, M.; Garrido, Daniel; Giavitto, G.; Godinović, N.; Hadasch, D.; Häfner, D.; Herrero, A.; Hildebrand, D.; Höhne-Mönch, D.; Hose, J.; Hrupec, Dario; Jogler, T.; Kellermann, H.; Klepser, S.; Krähenbühl, T.; Krause, J.; Kushida, J.; Barbera, A. La; Lelas, D.; Leonardo, E.; Lindfors, E.; Lombardi, S.; López, M.; López-Oramas, A.; Lorenz, E.; Makariev, M.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martı́nez, M.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Moldón, J.; Moralejo, A.; Munar-Adrover, P.; Nieto, D.; Nilsson, K.; Orito, R.; Otte, A. N.; Oya, I.; Paneque, D.; Paoletti, R.; Pardo, Sharon; Paredes, J. M.; Partini, S.; Pérez-Torres, M. A.; Peršić, M.; Peruzzo, L.; Pilia, M.; Pochon, J.; Prada, Francisco; Moroni, P. G. Prada; Prandini, E.; Gimenez, I. Puerto; Puljak, I.; Reichardt, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rissi, M.; Rügamer, S.; Saggion, A.; Saito, Koji; Saito, Takayuki; Salvati, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shayduk, M.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Šnidarić, Iva; Sobczyńska, D.; Spanier, F.; Spiro, S.; Stamatescu, V.; Stamerra, A.; Steinke, B.; Storz, J.; Strah, N.; Surić, T.; Takalo, L. O.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Tibolla, O.; Torres, D. F.; Treves, A.; Uellenbeck, M.; Vankov, H.; Vogler, P.; Wagner, R. M.; Weitzel, Q.; Zabalza, V.; Zandanel, F.; Zanin, R.; Hirotani, Kouichi

doi:10.1088/0004-637x/742/1/43

Cited by 84 publications

(84 citation statements)

References 56 publications

(76 reference statements)

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“…The spectra we obtain for the EGRET intervals are compatible with the monoscopic measurements from Aleksić et al (2011), considering that the statistical deviations are at most ∼2σ and many of the systematic errors of the two measurements are independent. Our stereoscopic measurements, however, support the possibility that the gamma-ray energy of MAGIC-mono data may have been over-estimated, as already discussed in Saito (2010).…”

Section: Energy Spectrasupporting

confidence: 79%

“…4 are unfolded; thus, the statistical errors are correlated by 20−60%, reflecting our energy resolution and bias, which vary from 15−40%, depending on the energy (see Aleksić et al 2012). Figure 4 also shows the Fermi-LAT spectra in the EGRET intervals as determined in Aleksić et al (2011). They extrapolate consistently to the monoscopic and stereoscopic spectra within systematic and statistical uncertainties.…”

Section: Energy Spectrasupporting

confidence: 53%

“…It is one of the few pulsars that have been detected in almost all energies, ranging from radio (e.g., Lyne et al 1993) to VHE gamma rays. In the highest-energy regime, it was detected up to a few tens of GeV by Fermi-LAT (Abdo et al 2010a), between approximately 25−100 GeV by MAGIC Saito 2010;Aleksić et al 2011) and above 100 GeV by VERITAS (Aliu et al 2011). The light curves and the spectra obtained by these observations suggest that gamma-ray pulsars have high-altitude emission zones that avoid a super-exponential spectral cutoff, which would be caused by magnetic pair production.…”

Section: Introductionmentioning

confidence: 77%

“…In this scenario, the cutoff energy corresponds to the highest characteristic curvature-radiation energy of the particles accelerated in the magnetosphere (e.g., Romani 1996). However, the spectrum of the Crab pulsar strongly disfavors an exponential cutoff (Aleksić et al 2011;Aliu et al 2011), making this pulsar a counterexample of the general property. Thus, to develop pulsar emission theories beyond the widely accepted curvature-radiation models, it is essential to examine the detailed phase-resolved spectrum of this youngest pulsar in the HE to VHE regimes.…”

Section: Introductionmentioning

confidence: 99%

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Phase-resolved energy spectra of the Crab pulsar in the range of 50–400 GeV measured with the MAGIC telescopes

Aleksić

Álvarez

Antonelli

et al. 2012

A&A

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We 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 pulse (P1) and the interpulse (P2) phase regions. We provide the widest spectra to date of the VHE components of both peaks, and these spectra extend to the energy range of satellite-borne observatories. The good resolution and background rejection of the stereoscopic MAGIC system allows us to cross-check the correctness of each spectral point of the pulsar by comparison with the corresponding (strong and well-known) Crab nebula flux. The spectra of both P1 and P2 are compatible with power laws with photon indices of 4.0 ± 0.8 (P1) and 3.42 ± 0.26 (P2), respectively, and the ratio P1/P2 between the photon counts of the two pulses is 0.54 ± 0.12. The VHE emission can be understood as an additional component produced by the inverse Compton scattering of secondary and tertiary e ± pairs on IR-UV photons.

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Section: Energy Spectrasupporting

confidence: 79%

Section: Energy Spectrasupporting

confidence: 53%

Section: Introductionmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Phase-resolved energy spectra of the Crab pulsar in the range of 50–400 GeV measured with the MAGIC telescopes

Aleksić

Álvarez

Antonelli

et al. 2012

A&A

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“…However, even this model has too many free parameters and, therefore, is subject to continuous modifications driven by new discoveries (Sect. 8.2 in Aleksic et al 2011). Any high-quality photometric and/or spectral data in the lowenergy range may shed light on the location and spatial extent of the regions of origin of emission which in outer-gap models comes from high-order generation cascades inside and outside the gaps.…”

Section: The Pulsar Multi-wavelength Spectrummentioning

confidence: 99%

The near-infrared detection of PSR B0540–69 and its nebula

Mignani

Luca

Hummel

et al. 2012

A&A

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Context. The ∼1700 year old PSR B0540−69 in the Large Magellanic Clouds (LMC) is considered the twin of the Crab pulsar because of its similar spin parameters, magnetic field, and energetics. PSR B0540−69 (V ∼ 22.5) is also one of the very few pulsars for which both optical pulsations and polarised emission have been measured. Its optical spectrum is fit by a power-law, ascribed to synchrotron radiation, like for the young Crab and Vela pulsars. At variance with them, however, a double break is required to join the X-ray and optical power-law spectra, with the first one possibly occurring in the near ultraviolet (nUV). Aims. Near-infrared (nIR) observations, never performed for PSR B0540−69, are crucial to determine whether the optical power-law spectrum extends to longer wavelengths or a new break occurs, like it happens for both the Crab and Vela pulsars in the mid-infrared (mIR), hinting at an even more complex particle energy and density distribution in the pulsar magnetosphere. Methods. We observed PSR B0540−69 in the J, H, and K S bands with the Very Large Telescope (VLT) to detect it, for the first time, in the nIR and characterise its optical-to-nIR spectrum. To disentangle the pulsar emission from that of its pulsar wind nebula (PWN), we obtained high-spatial resolution adaptive optics images with the NAOS-CONICA instrument (NACO). Results. We could clearly identify PSR B0540−69 in our J, H, and K S -band images and measure its flux (J = 20.14, H = 19.33, K S = 18.55, with an overall error of ±0.1 mag in each band). The joint fit to the available optical and nIR photometry with a powerlaw spectrum F ν ∝ ν −α gives a spectral index α = 0.70 ± 0.04, slightly more precise than measured in the optical only. This clearly implies that there is no spectral break between the optical and the nIR. We also detected, for the first time, the PSR B0540−69 PWN in the nIR. The comparison between our NACO images and Hubble Space Telescope (HST) optical ones does not reveal any apparent difference in the PWN morphology as a function of wavelength. The PWN optical-to-nIR spectrum is also fit by a single power-law, with spectral index α = 0.56 ± 0.03, slightly flatter than the pulsar's. Conclusions. Using NACO at the VLT, we obtained the first detection of PSR B0540−69 and its PWN in the nIR. Due to the small angular scale of the PWN (∼4 ) only the spatial resolution of the James Webb Space Telescope (JWST) will make it possible to extend the study of the pulsar and PWN spectrum towards the mid-IR.

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High‐energy pulsar models: Developments and new questions

Venter

Harding

2014

Astron Nachr

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The past few years have seen a major advance in observational knowledge of high-energy (HE) pulsars. The Fermi Large Area Telescope (LAT) and AGILE have increased the number of known γ-ray pulsars by an order of magnitude, its members being divided roughly equally among millisecond pulsars (MSPs), young radio-loud pulsars, and young radio-quiet pulsars. Many new and diverse emission characteristics are being measured, while radio and X-ray follow-up observations increase the pulsar detection rate and enrich our multiwavelength picture of these extreme sources. The wealth of new data has provided impetus for further development and improvement of existing theoretical pulsar models. Geometric light curve (LC) modelling has uncovered three broad classes into which HE pulsars fall: those where the radio profile leads, is aligned with, or lags the γ-ray profile. For example, the original MSP and original black widow system are members of the second class, requiring co-located emission regions and thereby breaking with traditional notions of radio emission origin. These models imply narrow accelerator gaps in the outer magnetosphere, indicating copious pair production even in MSP magnetospheres that were previously thought to be pair-starved. The increased quality and variety of the LCs necessitate construction of ever more sophisticated models. We will review progress in global magnetosphere solutions which specify a finite conductivity on field lines above the stellar surface, filling the gap between the standard vacuum and force-free (FF; plasma-filled) models. The possibility of deriving phase-resolved spectra for the brightest pulsars, coupled with the fact that the HE pulsar population is sizable enough to allow sampling of various pulsar geometries, will enable much more stringent testing of future radiation models. Reproduction of the observed phase-resolved behavior of this disparate group will be one of the next frontiers in pulsar science, impacting on our understanding of particle acceleration, emission, and magnetosphere geometry. One may now also study evolutionary trends of the measured or inferred quantities, and probe pulsar visibility and population properties such as radiation beam sizes of different pulsar classes, as well as the distribution of spin-down power, γ-ray luminosity, conversion efficiency, spectral index, and cutoff energy across the population. Lastly, the recent detection of very-high-energy (VHE) pulsations from the Crab pulsar generated quite a few ideas to explain this emission, leading to an extension of standard models and possibly even a bridge between the physics of pulsars and pulsar wind nebulae (PWNe).

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OBSERVATIONS OF THE CRAB PULSAR BETWEEN 25 AND 100 GeV WITH THE MAGIC I TELESCOPE

Cited by 84 publications

References 56 publications

Phase-resolved energy spectra of the Crab pulsar in the range of 50–400 GeV measured with the MAGIC telescopes

Phase-resolved energy spectra of the Crab pulsar in the range of 50–400 GeV measured with the MAGIC telescopes

The near-infrared detection of PSR B0540–69 and its nebula

High‐energy pulsar models: Developments and new questions

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