MAGIC Observations of PG 1553+113 during a Multiwavelength Campaign in July 2006

TL;DR

This paper reports MAGIC telescope observations of PG 1553+113 during a multiwavelength campaign, detecting very high energy gamma-ray emission with a significant flux and spectral analysis despite atmospheric challenges.

Contribution

First detection of PG 1553+113 at very high energies during a multiwavelength campaign with detailed spectral characterization.

Findings

Detected VHE gamma-ray emission with 5.0 sigma significance

Measured integral flux above 150 GeV as (2.6 +/- 0.9) x 10^{-7} ph/s/m^2

Derived a spectral index of -4.1 +/- 0.3 from the energy spectrum

Abstract

The active galactic nucleus PG 1553+113 was observed by the MAGIC telescope in July 2006 during a multiwavelength campaign, in which telescopes in the optical, X-ray, and very high energies participated. Although the MAGIC data were affected by strong atmospheric absorption (calima), they were analyzed after applying a correction. In 8.5 hours, a signal was detected with a significance of 5.0 sigma. The integral flux above 150 GeV was (2.6 +/- 0.9)*10^{-7} ph/s/m^2. By fitting the differential energy spectrum with a power law, a spectral index of -4.1 +/- 0.3 was obtained.