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Southern African Large Telescope Spectroscopy of BL Lacs for the CTA project
- Source :
- PoS, 37th International Cosmic Ray Conference, 37th International Cosmic Ray Conference, Jul 2021, Berlin, Germany. pp.881, ⟨10.22323/1.395.0881⟩
- Publication Year :
- 2021
- Publisher :
- HAL CCSD, 2021.
-
Abstract
- In the last two decades, very-high-energy gamma-ray astronomy has reached maturity: over 200 sources have been detected, both Galactic and extragalactic, by ground-based experiments. At present, Active Galactic Nuclei (AGN) make up about 40% of the more than 200 sources detected at very high energies with ground-based telescopes, the majority of which are blazars, i.e. their jets are closely aligned with the line of sight to Earth and three quarters of which are classified as high-frequency peaked BL Lac objects. One challenge to studies of the cosmological evolution of BL Lacs is the difficulty of obtaining redshifts from their nearly featureless, continuum- dominated spectra. It is expected that a significant fraction of the AGN to be detected with the future Cherenkov Telescope Array (CTA) observatory will have no spectroscopic redshifts, compromising the reliability of BL Lac population studies, particularly of their cosmic evolution. We started an effort in 2019 to measure the redshifts of a large fraction of the AGN that are likely to be detected with CTA, using the Southern African Large Telescope (SALT). In this contribution, we present two results from an on-going SALT program focused on the determination of BL Lac object redshifts that will be relevant for the CTA observatory.<br />15 pages, 4 figures, 37th International Cosmic Ray Conference
- Subjects :
- Active galactic nucleus
Cherenkov Telescope Array
Astrophysics::High Energy Astrophysical Phenomena
Population
FOS: Physical sciences
Astrophysics::Cosmology and Extragalactic Astrophysics
High Energy Physics - Experiment
blazar
High Energy Physics - Experiment (hep-ex)
Observatory
[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]
AGN
education
Blazar
Astrophysics::Galaxy Astrophysics
Physics
High Energy Astrophysical Phenomena (astro-ph.HE)
education.field_of_study
Astrophysics::Instrumentation and Methods for Astrophysics
Astronomy
redshift
Redshift
observatory
gamma ray: VHE
13. Climate action
galaxy
Southern African Large Telescope
Astrophysics - High Energy Astrophysical Phenomena
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
BL Lac object
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- PoS, 37th International Cosmic Ray Conference, 37th International Cosmic Ray Conference, Jul 2021, Berlin, Germany. pp.881, ⟨10.22323/1.395.0881⟩
- Accession number :
- edsair.doi.dedup.....630532d109b2ee11ef6624e49a06f60d