Master and servant

Weinstein, Jenny

doi:10.4324/9780203420690_chapter_18

Cited by 3 publications

(3 citation statements)

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“…After several publications on a small (∼ 10%) fraction of the current data set [14,15], it is the deepest and most comprehensive, high resolution (∼ 0.1 degrees) and sensitive ( 2% Crab Nebula point-source sensitivity) survey of the Milky Way in very-high-energy γ rays (0.2 E 100 TeV). Roughly ∼ 2700 hours of high-quality [10] and the VERITAS Cygnus survey [11,12] regions are illustrated in blue and green, respectively. From [13].…”

Section: Introductionmentioning

confidence: 99%

The Very High Energy Sky from ~ 20 GeV to Hundreds of TeV - Selected Highlights

Naurois

2016

Proceedings of the 34th International Cosmic Ray Conference — PoS(ICRC2015)

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After nearly a decade of operation, the three major arrays of atmospheric Cherenkov telescopes have revolutionized our view of the Very High Energy Universe, unveiling more than 100 sources of various types. MAGIC, consisting of two 17 m diameter telescopes on the Canary island of La Palma, and VERITAS, with four 12 m telescopes installed in southern Arizona, USA, have primarily explored the extragalactic sky, where the majority of the sources are active galactic nuclei (AGN), with γ-ray emission originating in their relativistic jets. In July 2014 MAGIC discovered the most distant source of very high energy γ rays, the gravitationally lensed blazar S3 0218 residing at the redshift of z = 0.944. The flat spectrum radio quasar PKS 1441+25 (z = 0.939), observed by MAGIC & VERITAS in 2015, showed a strong flaring activity over a time span of several weeks. Rapid variability from various BL Lacertae objects, down to minute timescales, has been observed by the three experiments, and measurement of their high-energy spectra allows the level of extragalactic background light to be constrained. Since the commissioning of the fifth, large (28 m diameter) telescope in December 2012, H.E.S.S.-II is the only array operating telescopes of different sizes together ("hybrid array "). The largest Cerenkov telescope ever built, CT5, provides an energy threshold of ∼ 20 GeV. With its broad energy range, H.E.S.S. explored the Galactic Plane with unprecedented sensitivity. The legacy release of the H.E.S.S. Galactic Plane Survey, consisting of 2800 hours of observations of the Galactic disk, reveals major new results. This is the first high-resolution (∼ 0.1 deg) sensitive (∼ 2% Crab Nebula point-source sensitivity) survey of the Milky Way in VHE γ rays. The Milky Way harbors a large variety of high energy sources of various types. In recent years, deep observations of several key Galactic regions of utmost importance for this field have been conducted by the three experiments. Among them are the Galactic Center region and its halo (particularly relevant for dark matter searches), the Cygnus region and its mysterious Milagro sources, the Crab Nebula and pulsar (surprisingly showing pulsed emission up to above 1 TeV), the iconic γ-ray supernova remnant RX J1713.7-3946 and other SNRs such as Tycho, the Vela pulsar and several binary systems such as LS 5039, PSR B1259-63, HESS J0632+057 and LS I +61 • 303. Joint observations on several of these objects proved to be the most efficient way to understand their nature. A deep observation of the Large Magellanic Cloud revealed, for the first time, spectacular and powerful accelerators of stellar origin outside our own galaxy. Highlights of these observations with H.E.S.S., MAGIC and VERITAS have been presented and discussed at the conference.

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Section: Introductionmentioning

confidence: 99%

The Very High Energy Sky from ~ 20 GeV to Hundreds of TeV - Selected Highlights

Naurois

2016

Proceedings of the 34th International Cosmic Ray Conference — PoS(ICRC2015)

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“…Details of the preliminary survey analysis, based on all VERITAS data in the region through Fall 2009, are given in [9,10]. Figure 1 shows the resulting VERITAS background-subtracted sky map of the portion of the survey region with 74…”

Section: Survey Strategy and Initial Resultsmentioning

confidence: 99%

The Cygnus region of the galaxy: A VERITAS perspective

Weinstein

2015

EPJ Web of Conferences

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Abstract. The Cygnus-X star-forming region ("Cygnus") is the richest star-forming region within 2 kpc of Earth and is home to a wealth of potential cosmic ray accelerators, including supernova remnants, massive star clusters, and pulsar wind nebulae. Over the past five years, discoveries by several gamma-ray observatories sensitive in different energy bands, including the identification by Fermi-LAT of a potential cocoon of freshly accelerated cosmic rays, have pinpointed this region as a unique laboratory for studying the early phases of the cosmic ray life cycle. From 2007 to 2009 VERITAS, a very high energy (VHE; E > 100 GeV) observatory in southern Arizona, undertook an extensive survey of the Cygnus region from 67 to 82 degrees Galactic longitude and from −1 to 4 degrees in Galactic latitude. In the years since, VERITAS has continued to accumulate data at specific locations within the survey region. We will review the discoveries and insights that this rich dataset has already provided. We will also consider the key role that we expect these data to play in interpreting the complex multiwavelength picture we have of the Cygnus region, particularly in the vicinity of the Cygnus cocoon. As part of this discussion we will summarize ongoing studies of VERITAS data in the Cygnus region, including the development of new data analysis techniques that dramatically increase VERITAS' sensitivity to sources on scales larger than a square degree. IntroductionSupernova remnants (SNRs) are believed to produce the bulk of Galactic cosmic rays up to the "knee" at 10 15 eV, a theory supported by recent GeV and TeV γ -ray and X-ray observations [1][2][3][4][5]. However, so far conclusive evidence for protons being accelerated all the way to the knee by SNR shocks has been elusive. Recent theoretical models indicate that SNRs are PeVatrons for only a brief portion of their life cycle (as little as 30 years) and that the highest energy protons escape early [6]. The number of nearby historical supernova remnants is small and the number of potential PeVatrons even smaller. It is therefore interesting to hunt for other sources of gamma-ray emission that can be identified with populations recently-accelerated cosmic rays, whether these are cosmic rays recently escaped from their accelerator or the result of the collective action of multiple hadronic cosmic ray accelerators (e.g. superbubbles).From this point of view, the Cygnus region-rich both in potential VHE gamma-ray sources and likely cosmic ray accelerators, including a superbubble-was a natural choice for a VHE gamma-ray survey by the VERITAS observatory. Cygnus is known to be the richest starforming region within 2 kpc of Earth and to contain high mass of molecular gas (more than ten times that of its neighboring star-forming regions combined) [7]. It contains a treasure trove of massive stars in stellar nurseries, young open clusters, and OB associations, two of which-Cyg OB1 and OB2 [8]-are of particular interest. The EGRET catalog as well as known supernova a e-mail: am...

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“…Section 6 is devoted to technical tests of our code. Section 7 shows the comparison of numerical results from running the new version of TAUOLA with the relatively old one based on the CLEO parameterization [16][17][18][19] which is still widely in use despite the recent significant progress achieved by CLEO [3,4]. Chapter 8 briefly summarizes the main results of the paper.…”

Section: Introductionmentioning

confidence: 99%