Article

# Discovery of TeV Gamma Ray Emission from Tycho's Supernova Remnant

The Astrophysical Journal Letters (Impact Factor: 5.6). 02/2011; 730(2). DOI: 10.1088/2041-8205/730/2/L20
Source: arXiv

ABSTRACT We report the discovery of TeV gamma-ray emission from the Type Ia supernova
remnant (SNR) G120.1+1.4, known as Tycho's supernova remnant. Observations
performed in the period 2008-2010 with the VERITAS ground-based gamma-ray
observatory reveal weak emission coming from the direction of the remnant,
compatible with a point source located at $00^{\rm h} \ 25^{\rm m} \ 27.0^{\rm s},\ +64^{\circ} \ 10^{\prime} \ 50^{\prime\prime}$ (J2000). The TeV photon
spectrum measured by VERITAS can be described with a power-law $dN/dE = C(E/3.42\;\textrm{TeV})^{-\Gamma}$ with $\Gamma = 1.95 \pm 0.51_{stat} \pm 0.30_{sys}$ and $C = (1.55 \pm 0.43_{stat} \pm 0.47_{sys}) \times 10^{-14}$
cm$^{-2}$s$^{-1}$TeV$^{-1}$. The integral flux above 1 TeV corresponds to $\sim 0.9%$ percent of the steady Crab Nebula emission above the same energy, making
it one of the weakest sources yet detected in TeV gamma rays. We present both
leptonic and hadronic models which can describe the data. The lowest magnetic
field allowed in these models is $\sim 80 \mu$G, which may be interpreted as
evidence for magnetic field amplification.

0 Bookmarks
·
179 Views
• ##### Article: The Pierre Auger Observatory: Challenges at the highest-energy frontier
Physics Procedia 01/2012; 37:1355-1364.
• ##### Article: THREE-DIMENSIONAL SIMULATIONS OF THE NON-THERMAL BROADBAND EMISSION FROM YOUNG SUPERNOVA REMNANTS INCLUDING EFFICIENT PARTICLE ACCELERATION
[Hide abstract]
ABSTRACT: Supernova remnants are believed to be major contributors to Galactic cosmic rays. In this paper, we explore how the non-thermal emission from young remnants can be used to probe the production of energetic particles at the shock (both protons and electrons). Our model couples hydrodynamic simulations of a supernova remnant with a kinetic treatment of particle acceleration. We include two important back-reaction loops upstream of the shock: energetic particles can (1) modify the flow structure and (2) amplify the magnetic field. As the latter process is not fully understood, we use different limit cases that encompass a wide range of possibilities. We follow the history of the shock dynamics and of the particle transport downstream of the shock, which allows us to compute the non-thermal emission from the remnant at any given age. We do this in three dimensions, in order to generate projected maps that can be compared with observations. We observe that completely different recipes for the magnetic field can lead to similar modifications of the shock structure, although to very different configurations of the field and particles. We show how this affects the emission patterns in different energy bands, from radio to X-rays and γ-rays. High magnetic fields (>100 μG) directly impact the synchrotron emission from electrons, by restricting their emission to thin rims, and indirectly impact the inverse Compton emission from electrons and also the pion decay emission from protons, mostly by shifting their cut-off energies to respectively lower and higher energies.
The Astrophysical Journal 06/2014; 789(1):49. · 6.28 Impact Factor
• ##### Article: Neutrino astrophysics with IceCube
[Hide abstract]
ABSTRACT: IceCube is a neutrino observatory in operation at the geographical South Pole. The main objective of IceCube is to conduct very-high-energy neutrino astronomy, including the search for the sources of cosmic rays. IceCube operates by measuring Cherenkov light from particles produced in neutrino-matter interactions. IceCube has made multiple observations including atmospheric neutrinos and cosmic ray anisotropy. For the first time, IceCube is reporting the observation of 28 events consistent with an astrophysical origin. The events have energies that range from ≈30 TeV to ≈1.2 PeV. The atmospheric origin of the events is excluded at the 4.1σlevel. In these proceedings we summarize the study of these 28 events. We also present the results of the search for neutrinos in coincidence with GRB 130427A.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 03/2014; 742. · 1.32 Impact Factor