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

TL;DR

This paper reports the first detection of TeV gamma-ray emission from Tycho's supernova remnant, revealing a weak source that supports models of magnetic field amplification and particle acceleration.

Contribution

The discovery of TeV gamma-ray emission from Tycho's SNR is new, providing insights into particle acceleration and magnetic field amplification in Type Ia supernova remnants.

Findings

Detected TeV gamma-ray emission from Tycho's SNR with VERITAS.

Measured a power-law spectrum with index ~1.95.

Found the emission is about 0.9% of Crab Nebula flux.

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.