Hunting distant BL Lacs with the photometric technique using Swift and SARA

Abstract

BL Lacertae objects (BL Lacs) represent a large fraction (22\%) of gamma-ray sources in the Third Fermi Large Area Telescope catalog (3FGL). Nearly half of the BL Lac population remains without a redshift because of their featureless optical spectra. We aim to increase the number of BL Lacs with a redshift measurement by using the photometric technique. For this work, we have used 6 Swift-UVOT filters and SDSS g,r,i,z optical filters mounted on the 0.65 m SARA-CTIO located in Chile and the 1.0 m SARA-ORM in 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 3 sources with z>1.3 while reliable upper limits have been derived for 17 sources. The results presented here bring the total number of high-z (z>1.3) BL Lacs to 29.

References in corpus (49)

• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• Unified Schemes for Radio-Loud Active Galactic Nuclei
• The Swift Ultra-Violet/Optical Telescope
• Accurate photometric redshifts for the CFHT Legacy Survey calibrated using the VIMOS VLT Deep Survey
• Fermi Large Area Telescope Fourth Source Catalog
• Evolutionary models for very-low-mass stars and brown dwarfs with dusty atmospheres
• Fermi Large Area Telescope First Source Catalog
• A Unifying View of the Spectral Energy Distributions of Blazars
• Neutrino emission from the direction of the blazar TXS 0506+056 prior to the IceCube-170922A alert
• Measuring and Modelling the Redshift Evolution of Clustering: the Hubble Deep Field North
• Photometric Calibration of the Swift Ultraviolet/Optical Telescope
• The Cosmic Infrared Background: Measurements and Implications
• Extragalactic Background Light Inferred from AEGIS Galaxy SED-type Fractions
• The Second Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope
• The Connection between X-ray- and Radio-Selected BL Lacertae Objects
• Modeling the Extragalactic Background Light from Stars and Dust
• A low level of extragalactic background light as revealed by gamma-rays from blazars
• Semi-analytic modeling of the EBL and consequences for extragalactic gamma-ray spectra
• The Third Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope
• The Thirteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey MApping Nearby Galaxies at Apache Point Observatory
• Photometric redshift and classification for the XMM-COSMOS sources
• 3FHL: The Third Catalog of Hard Fermi-LAT Sources
• UBVRI Photometric Standard Stars Around the Celestial Equator: Updates and Additions
• The Fermi blazar sequence
• The Imprint of The Extragalactic Background Light in the Gamma-Ray Spectra of Blazars
• CGRaBS: An All-Sky Survey of Gamma-Ray Blazar Candidates
• Dissecting Photometric redshift for Active Galactic Nuclei using XMM- and Chandra-COSMOS samples
• The Fermi blazars divide
• Spectroscopy of The Largest Ever Gamma-ray Selected BL Lac Sample
• TXS 0506+056, the first cosmic neutrino source, is not a BL Lac
• A $\gamma$-ray determination of the Universe's star-formation history
• The relation between broad lines and gamma--ray luminosities in Fermi blazars
• Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe
• Multiwavelength Observations of the Powerful Gamma-ray Quasar PKS 1510-089: Clues on the Jet Composition
• Detection of the cosmic γ-ray horizon from multiwavelength observations of blazars
• BL Lacertae objects beyond redshift 1.3 - UV-to-NIR photometry and photometric redshift for Fermi/LAT blazars
• A new measurement of the Hubble constant and matter content of the Universe using extragalactic background light $\gamma$-ray attenuation
• General Physical Properties of CGRaBS Blazars
• Spectral analysis of Fermi-LAT blazars above 50 GeV
• The discovery of high power - high synchrotron peak blazars
• Blue Fermi Flat Spectrum Radio Quasars
• Reconstructing the γ-ray Photon Optical Depth of the Universe to z~4 from Multiwavelength Galaxy Survey Data
• The Remote Observatories of the Southeastern Association for Research in Astronomy (SARA)
• Measurement of the expansion rate of the Universe from γ-ray attenuation
• BeppoSAX Observations of Synchrotron X-ray Emission from Radio Quasars
• New High-z Fermi BL Lacs with the Photometric Dropout Technique
• New high-z BL Lacs using the photometric method with Swift and SARA
• NuSTAR Observations and multi-wavelength modeling of the high-redshift BL Lac Object 4FGL J2146.5-1344
• Parameter Correlations and Cosmological Properties of BL Lac Objects

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• Identifying the 3FHL catalog: V. Results of the CTIO-COSMOS optical spectroscopy campaign 2019
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