The unidentified TeV source (TeVJ2032+4130) and surrounding field: Final HEGRA IACT-System results

TL;DR

This paper confirms the steady, extended TeV gamma-ray source TeVJ2032+4130 in Cygnus, with detailed measurements of its spectrum, size, and flux, but no identified counterpart at other wavelengths.

Contribution

First definitive confirmation and detailed characterization of the TeVJ2032+4130 source using HEGRA data from 1999 to 2002.

Findings

Source is steady over four years

Extended with radius 6.2 arcmin

Hard spectrum with photon index -1.9

Abstract

The unidentified TeV source in Cygnus is now confirmed by follow-up observations from 2002 with the HEGRA stereoscopic system of Cherenkov Telescopes. Using all data (1999 to 2002) we confirm this new source as steady in flux over the four years of data taking, extended with radius 6.2 arcmin (+-1.2 arcmin (stat) +-0.9 arcmin (sys)) and exhibiting a hard spectrum with photon index -1.9. It is located in the direction of the dense OB stellar association, Cygnus OB2. Its integral flux above energies E>1 TeV amounts to \~5% of the Crab assuming a Gaussian profile for the intrinsic source morphology. There is no obvious counterpart at radio, optical nor X-ray energies, leaving TeVJ2032+4130 presently unidentified. Observational parameters of this source are updated here and some astrophysical discussion is provided. Also included are upper limits for a number of other interesting sources in the FoV, including the famous microquasar Cygnus X-3.