Optical spectral characterization of the the TeV extreme blazar 2WHSP J073326.7+515354

Abstract

The emission from the relativistic jets in blazars usually outshines their host galaxies, challenging the determination of their distances and the characterization of the stellar population. The situation becomes more favorable in the case of the extreme blazars (EHBLs), for which the bulk of the emission of the relativistic jets is emitted at higher energies, unveiling the optical emission from the host galaxy. The distance determination is fundamental for the study of the intrinsic characteristics of the blazars, especially to estimate the intrinsic gamma-ray spectra distorted due to the interaction with the Extragalactic Background Light. In this work we report on the properties of 2WHSP~J073326.7+515354 host galaxy in the optical band, which is one of the few EHBLs detected at TeV energies. We present the first measurement of the distance of the source, $\mathrm{z}=0.06504\pm 0.00002$ (velocity dispersion $\sigma =237\pm 9\mathrm{km}{\mathrm{s}}^{-1}$). We also perform a detailed study of the stellar population of its host galaxy. We find that the mass-weighted mean stellar age is $11.72\pm 0.06\mathrm{Gyr}$ and the mean metallicity $[M/H]=0.159\pm 0.016$. In addition, a morphological study of the host galaxy is also carried out. The surface brightness distribution is modelled by a composition of a dominant classical bulge ($R_e=3.77\pm1\arcsec $ or equivalently 4.74~kpc) plus an unresolved source which corresponds to the active nucleus. The black hole mass is estimated using both the mass relation with the velocity dispersion and the absolute magnitude from the bulge yielding comparable results: $(4.8\pm 0.9)\times 10^8{M}_{\odot }$ and $(3.7\pm 1.0)\times 10^8{M}_{\odot }$, respectively.

Accepted for publication in MNRAS

References in corpus (9)

• The Host Galaxies and Classification of Active Galactic Nuclei
• Improving the full spectrum fitting method: accurate convolution with Gauss-Hermite functions
• Evolutionary Stellar Population Synthesis with MILES. Part I: The Base Models and a New Line Index System
• An Analysis of the Shapes of Interstellar Extinction Curves. V. The IR-Through-UV Curve Morphology
• Empirical Color Transformations Between SDSS Photometry and Other Photometric Systems
• Correcting for Telluric Absorption: Methods, Case Studies, and Release of the TelFit Code
• 2WHSP: A catalog of HE and VHE gamma-ray blazars and blazar candidates
• Probing the Physics of Narrow Line Regions in Active Galaxies III: Accretion and Cocoon Shocks in the LINER NGC1052
• A photometric study of the peculiar and potentially double ringed, non-barred galaxy: PGC 1000714

Cited by in corpus (4)

• The Central Engines of Fermi Blazars
• Optical spectral characterization of the gamma-ray blazars S4 0954+65, TXS 1515-273 and RX J0812.0+0237
• Absorption features in sub-TeV gamma-ray spectra of BL Lac objects
• Very high energy emission mechanism in the extreme blazar PGC 2402248