New methods of atmospheric Cherenkov imaging for gamma-ray astronomy. I. The false source method

Fomin, V. P.; Степанян, А. А.; Lamb, R. C.; Lewis, D. A.; Punch, M.; Weekes, T. C.

doi:10.1016/0927-6505(94)90036-1

Cited by 309 publications

(254 citation statements)

References 11 publications

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“…108 VERITAS observations of Mrk 421 were carried out under good weather conditions during the period of the NuSTAR campaign, resulting in a total, quality-selected exposure time of 15.5 hr during the period 2013January10 to 2013March17, almost all of which is strictly simultaneous with NuSTAR exposures. These observations were taken at 0°.5 offset in each of four cardinal directions from the position of Mrk 421 to enable simultaneous background estimation using the "false-source tracking" method (Fomin et al 1994). Detected events are parameterized by the principal moments of the elliptical images of the Cherenkov shower in each camera (Hillas 1985).…”

Section: Veritasmentioning

confidence: 99%

“…Most of these observations (8 hr in total) were strictly simultaneous with the NuSTAR observations. They were performed in the "false-source tracking" mode (Fomin et al 1994), where the target source position has an offset of 0°.4 from the camera center, so that both signal and background data are taken simultaneously. Those data were analyzed following the standard procedure described in Aleksić et al (2016b), using the MAGIC Analysis and Reconstruction Software (MARS; Moralejo et al 2009).…”

Section: Magicmentioning

confidence: 99%

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MULTIWAVELENGTH STUDY OF QUIESCENT STATES OF Mrk 421 WITH UNPRECEDENTED HARD X-RAY COVERAGE PROVIDED BY NuSTAR IN 2013

Baloković¹,

Paneque²,

Madejski³

et al. 2016

ApJ

116

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We present coordinated multiwavelength observations of the bright, nearby BL Lacertae object Mrk 421 taken in 2013 January-March, involving GASP-WEBT, Swift, NuSTAR, Fermi-LAT, MAGIC, VERITAS, and other collaborations and instruments, providing data from radio to very high energy(VHE) γ-ray bands. NuSTAR yielded previously unattainable sensitivity in the 3-79keV range, revealing that the spectrum softens when the source is dimmer until the X-ray spectral shape saturates into a steep 3 G » power law, with no evidence for an exponential cutoff or additional hard components up to ∼80keV. For the first time, we observed both the synchrotron and the inverse-Compton peaks of the spectral energy distribution (SED) simultaneously shifted to frequencies below the typical quiescent state by an order of magnitude. The fractional variability as a function of photon energy shows a double-bump structure that relates to the two bumps of the broadband SED. In each bump, the variability increases with energy, which, in the framework of the synchrotron self-Compton model, implies that the electrons with higher energies are more variable. The measured multi band variability, the significant X-ray-to-VHE correlation down to some of the lowest fluxes ever observed in both bands, the lack of correlation between optical/UV and X-ray flux, the low degree of polarization and its significant (random) variations, the short estimated electron cooling time, and the significantly longer variability timescale observed in the NuSTAR light curves point toward in situ electron acceleration and suggest that there are multiple compact regions contributing to the broadband emission of Mrk 421 during low-activity states.

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Section: Veritasmentioning

confidence: 99%

Section: Magicmentioning

confidence: 99%

MULTIWAVELENGTH STUDY OF QUIESCENT STATES OF Mrk 421 WITH UNPRECEDENTED HARD X-RAY COVERAGE PROVIDED BY NuSTAR IN 2013

Baloković¹,

Paneque²,

Madejski³

et al. 2016

ApJ

116

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“…All the data were taken in the false-source tracking mode (wobble, Fomin et al 1994), in which the telescopes alternate between two sky positions every 20 min at 0.4 • offset from the source.…”

Section: Observations and Data Analysismentioning

confidence: 99%

Discovery of very high energy gamma-ray emission from the blazar 1ES 1727+502 with the MAGIC Telescopes

Aleksić¹,

Antonelli²,

Antoranz³

et al. 2014

A&A

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Motivated by the prediction of a high TeV luminosity we investigated whether the blazar 1ES 1727+502 (z = 0.055) is emitting very high energy (VHE, E > 100 GeV) γ rays. We observed the BL Lac object 1ES 1727+502 in stereoscopic mode with the two MAGIC telescopes for 14 nights between May 6th and June 10th 2011, for a total effective observing time of 12.6 h. To study the multiwavelength spectral energy distribution (SED), we used simultaneous optical R-band data from the KVA telescope, archival UV/optical and X-ray observations from instruments UVOT and XRT on board of the Swift satellite, and high energy (HE, 0.1 GeV-100 GeV) γ-ray data from the Fermi-LAT instrument. We detected, for the first time, VHE γ-ray emission from 1ES 1727+502 at a statistical significance of 5.5σ. The integral flux above 150 GeV is estimated to be (2.1 ± 0.4)% of the Crab nebula flux and the de-absorbed VHE spectrum has a photon index of (2.7 ± 0.5). No significant short-term variability was found in any of the wavebands presented here. We model the SED using a one-zone synchrotron self-Compton model obtaining parameters typical for this class of sources.

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“…The active trigger area, which in all MAGIC cameras is limited to a central area in the FoV, was enlarged from ∼ 0.9 deg radius (trigger area of the old MAGIC-I camera) to ∼ 1.2 deg radius (in the MAGIC-II camera), still using the same trigger electronics as for the MAGIC-I camera but reducing the size of overlapping sectors (see Section 3). The main motivation for enlarging the sensitive trigger area was to adapt to the stereo approach and increase sensitivity to extended γ-ray sources as well as a more suitable usage of the so-called wobble mode (pointing to a source of interest at some 0.4 deg off-center, Fomin et al 1994) for a better background estimation.…”

Section: Introductionmentioning

confidence: 99%

The major upgrade of the MAGIC telescopes, Part I: The hardware improvements and the commissioning of the system

Aleksić

Ansoldi

Antonelli

et al. 2016

Astroparticle Physics

221

123

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Figure 1: The two 17 m diameter MAGIC telescope system operating at the Roque de los Muchachos observatory in La Palma. The telescope in front is MAGIC-II. AbstractThe 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 GeV to more than 50 TeV. The two telescopes were built in 2004 and 2009, respectively, with different cameras, triggers and readout systems. In the years 2011-2012 the MAGIC collaboration undertook a major upgrade to make the stereoscopic system uniform, improving its overall performance and easing its maintenance. In particular, the camera, the receivers and the trigger of the first telescope were replaced and the readout of the two telescopes was upgraded. This paper (Part I) describes the details of the upgrade as well as the basic performance parameters of MAGIC such as raw data treatment, linearity in the electronic chain and sources of noise. In Part II, we describe the physics performance of the upgraded system.

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New methods of atmospheric Cherenkov imaging for gamma-ray astronomy. I. The false source method

Cited by 309 publications

References 11 publications

MULTIWAVELENGTH STUDY OF QUIESCENT STATES OF Mrk 421 WITH UNPRECEDENTED HARD X-RAY COVERAGE PROVIDED BY NuSTAR IN 2013

MULTIWAVELENGTH STUDY OF QUIESCENT STATES OF Mrk 421 WITH UNPRECEDENTED HARD X-RAY COVERAGE PROVIDED BY NuSTAR IN 2013

Discovery of very high energy gamma-ray emission from the blazar 1ES 1727+502 with the MAGIC Telescopes

The major upgrade of the MAGIC telescopes, Part I: The hardware improvements and the commissioning of the system

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