Fermi/LAT discovery of gamma-ray emission from the flat-spectrum radio quasar PKS 1454-354

TL;DR

This paper reports the first detection of gamma-ray emission from the flat-spectrum radio quasar PKS 1454-354 by Fermi/LAT, including a rapid flare and multiwavelength follow-up confirming its active state.

Contribution

First identification of gamma-ray emission from PKS 1454-354, linking it to an unidentified EGRET source and providing multiwavelength observational confirmation.

Findings

Detected a gamma-ray flare with peak flux on 4 September 2008.

PKS 1454-354 identified as the likely counterpart of 3EG J1500-3509.

Multiwavelength data show increased flux across radio, optical, UV, and X-ray bands.

Abstract

We report the discovery by the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope of high-energy gamma-ray (GeV) emission from the flat-spectrum radio quasar PKS 1454-354 (z=1.424). On 4 September 2008 the source rose to a peak flux of (3.5 +/- 0.7)x 10^-6 ph cm^-2 s^-1 (E > 100 MeV) on a time scale of hours and then slowly dropped over the following two days. No significant spectral changes occurred during the flare. Fermi/LAT observations also showed that PKS 1454-354 is the most probable counterpart of the unidentified EGRET source 3EG J1500-3509. Multiwavelength measurements performed during the following days (7 September with Swift; 6-7 September with the ground-based optical telescope ATOM; 13 September with the Australia Telescope Compact Array) resulted in radio, optical, UV and X-ray fluxes greater than archival data, confirming the activity of PKS 1454-354.