Resolving the Host Galaxy of a Distant Blazar with LBT/LUCI1 + ARGOS
Abstract
BL Lac objects emitting in the Very High Energy (VHE) regime are unique tools to peer into the properties of the Extragalactic Background Light (EBL). However, due to the typical absence of features in their spectra, the determination of their redshifts has proven challenging. In this work we exploit the superb spatial resolution delivered by the new Advanced Rayleigh guided Ground layer adaptive Optics System (ARGOS) at the Large Binocular Telescope to detect the host galaxy of HESS J1943+213, a VHE emitting BL Lac shining through the Galaxy. Deep H-band imaging collected during the ARGOS commissioning allowed us to separate the contribution of the nuclear emission and to unveil the properties of the host galaxy with unprecedented detail. The host galaxy is well fitted by a S\'ersic profile with index of n~2 and total magnitude of H~16.15 mag. Under the assumption that BL Lac host galaxies are standard candles, we infer a redshift of z~0.21. In the framework of the current model for the EBL, this value is in agreement with the observed dimming of the VHE spectrum due to the scatter of energetic photons on the EBL.
Keywords
Cite
@article{arxiv.1801.08157,
title = {Resolving the Host Galaxy of a Distant Blazar with LBT/LUCI1 + ARGOS},
author = {Emanuele Paolo Farina and Iskren Y. Georgiev and Roberto Decarli and Tomislav Terzić and Lorenzo Busoni and Wolfgang Gässler and Tommaso Mazzoni and José L. Borelli and Matthias Rosensteiner and Julian Ziegleder and Marco Bonaglia and Sebastian Rabien and Peter Buschkamp and Gilles Orban de Xivry and Gustavo Rahmer and Martin Kulas and Diethard Peter},
journal= {arXiv preprint arXiv:1801.08157},
year = {2018}
}
Comments
6 pages, 4 figures, 1 table. If you would like to have access to the fully reduced H-band image of HESS J1943+213 please inquire the first Author or check https://github.com/EmAstro/LBT_ARGOS/. Accepted for publication in MNRAS