skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: On the Redshift of TeV BL Lac Objects

Abstract

We report results of a spectroscopic campaign carried out at the 10 m Gran Telescopio Canarias for a sample of 22 BL Lac objects detected (or candidates) at TeV energies, aiming to determine or constrain their redshift. This is of fundamental importance for the interpretation of their emission models and for population studies and is also mandatory for studying the interaction of high-energy photons with the extragalactic background light using TeV sources. Optical spectra with high signal-to-noise ratios in the range 4250–10000 Å were obtained to search for faint emission or absorption lines from both the host galaxy and the nucleus. We determine a new redshift for PKS 1424+240 ( z = 0.604) and a tentative one for 1ES 0033+595 ( z = 0.467). We are able to set new spectroscopic redshift lower limits for three other sources on the basis of Mg ii and Ca ii intervening absorption features: BZB J1243+3627 ( z > 0.483), BZB J1540+8155 ( z > 0.672), and BZB 0J2323+4210 ( z > 0.267). We confirm previous redshift estimates for four blazars: S3 0218+357 ( z = 0.944), 1ES 1215+303 ( z = 0.129), W Comae ( z = 0.102), and MS 1221.8+2452 ( zmore » = 0.218). For the remaining targets, in seven cases (S2 0109+22, 3C 66A, VER J0521+211, S4 0954+65, BZB J1120+4214, S3 1227+25, BZB J2323+4210), we do not validate the proposed redshift. Finally, for all sources of still-unknown redshift, we set a lower limit based on the minimum equivalent width of absorption features expected from the host galaxy.« less

Authors:
;  [1]; ;  [2];  [3];  [4]
  1. INAF, Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5 I-35122 Padova (PD) (Italy)
  2. INAF, Osservatorio Astronomico di Brera, Via E. Bianchi 46 I-23807 Merate (Italy)
  3. Università degli Studi dell’Insubria, Via Valleggio 11 I-22100 Como (Italy)
  4. Instituto de Astrofisica de Canarias, C/O Via Lactea, s/n E38205—La Laguna (Tenerife) (Spain)
Publication Date:
OSTI Identifier:
22661289
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 837; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; BL LACERTAE OBJECTS; EMISSION; GALAXIES; GAMMA RADIATION; INTERACTIONS; PHOTONS; QUASARS; RED SHIFT; SIGNAL-TO-NOISE RATIO; SPECTRA; TEV RANGE; VISIBLE RADIATION

Citation Formats

Paiano, Simona, Falomo, Renato, Landoni, Marco, Righi, Chiara, Treves, Aldo, and Scarpa, Riccardo. On the Redshift of TeV BL Lac Objects. United States: N. p., 2017. Web. doi:10.3847/1538-4357/837/2/144.
Paiano, Simona, Falomo, Renato, Landoni, Marco, Righi, Chiara, Treves, Aldo, & Scarpa, Riccardo. On the Redshift of TeV BL Lac Objects. United States. doi:10.3847/1538-4357/837/2/144.
Paiano, Simona, Falomo, Renato, Landoni, Marco, Righi, Chiara, Treves, Aldo, and Scarpa, Riccardo. Fri . "On the Redshift of TeV BL Lac Objects". United States. doi:10.3847/1538-4357/837/2/144.
@article{osti_22661289,
title = {On the Redshift of TeV BL Lac Objects},
author = {Paiano, Simona and Falomo, Renato and Landoni, Marco and Righi, Chiara and Treves, Aldo and Scarpa, Riccardo},
abstractNote = {We report results of a spectroscopic campaign carried out at the 10 m Gran Telescopio Canarias for a sample of 22 BL Lac objects detected (or candidates) at TeV energies, aiming to determine or constrain their redshift. This is of fundamental importance for the interpretation of their emission models and for population studies and is also mandatory for studying the interaction of high-energy photons with the extragalactic background light using TeV sources. Optical spectra with high signal-to-noise ratios in the range 4250–10000 Å were obtained to search for faint emission or absorption lines from both the host galaxy and the nucleus. We determine a new redshift for PKS 1424+240 ( z = 0.604) and a tentative one for 1ES 0033+595 ( z = 0.467). We are able to set new spectroscopic redshift lower limits for three other sources on the basis of Mg ii and Ca ii intervening absorption features: BZB J1243+3627 ( z > 0.483), BZB J1540+8155 ( z > 0.672), and BZB 0J2323+4210 ( z > 0.267). We confirm previous redshift estimates for four blazars: S3 0218+357 ( z = 0.944), 1ES 1215+303 ( z = 0.129), W Comae ( z = 0.102), and MS 1221.8+2452 ( z = 0.218). For the remaining targets, in seven cases (S2 0109+22, 3C 66A, VER J0521+211, S4 0954+65, BZB J1120+4214, S3 1227+25, BZB J2323+4210), we do not validate the proposed redshift. Finally, for all sources of still-unknown redshift, we set a lower limit based on the minimum equivalent width of absorption features expected from the host galaxy.},
doi = {10.3847/1538-4357/837/2/144},
journal = {Astrophysical Journal},
number = 2,
volume = 837,
place = {United States},
year = {Fri Mar 10 00:00:00 EST 2017},
month = {Fri Mar 10 00:00:00 EST 2017}
}