Year: 2020
Type: article
Abstract: BL Lacertae objects represent a large fraction (22%) of γ-ray sources in the Third Fermi Large Area Telescope catalog (3FGL). Nearly half of the BL Lac object population remains without a redshift because of their featureless optical spectra. We aim to increase the number of BL Lac objects with a redshift measurement by using the photometric technique. For this work, we have used six Swift-UVOT filters and SDSS g′, r′, i′, and z′ optical filters mounted on the 0.65 m SARA–CTIO located in Chile and the 1.0 m SARA–ORM in the Canary Islands. A sample of 45 sources was selected from the 3FGL catalog for which photometry was performed in 10 optical and UV filters to obtain redshift measurements. We found three sources with z > 1.3, while reliable upper limits have been provided for 17 sources. The results presented here bring the total number of high-z (z > 1.3) BL Lac objects to 29.
Source: The Astrophysical Journal
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Awards: G1761556946, THE CLASS OF AGNS CALLED BLAZARS ARE PROMINENT MEMBERS OF FERMI DETECTED SOURCES. THE STUDY OF BLAZAR EVOLUTION WITH REDSHIFT IS IMPORTANT IN ITS OWN RIGHT BUT PERHAPS MORE IMPORTANTLY THEY PROVIDE A POWERFUL DIAGNOSTIC TOOL TO STUDY THE EVOLUTION OF THE EXTRAGALACTIC BACKGROUND LIGHT (EBL). USING BLAZARS AS COSMOLOGICAL PROBES REQUIRES KNOWLEDGE OF THEIR REDSHIFT. WE PROPOSE TO JOINTLY USE SWIFT-UVOT AND SARA-CT A 0.65 M TELESCOPE AT CERRO TOLOLO CHILE TO DERIVE PHOTOMETRIC REDSHIFTS FOR SOURCES ABOVE Z ~ 1.3. THIS METHOD MAKES USE OF 10 UV-OPTICAL FILTERS WHICH ALLOWS FOR RELIABLE REDSHIFT MEASUREMENTS. THIS PROJECT WILL DELIVER MEASUREMENTS OF THE SPECTRAL ENERGY DISTRIBUTIONS FOR 14 NEW 3FGL BLAZARS AND ESTABLISH PHOTOMETRIC REDSHIFTS FOR THOSE WITH Z>1.3.
OpenAlex ID: W3006445586