NOAO >   Observing Info >   Approved Programs >   2017A-0286

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Program Information for 2017A-0286


PI: Amanpreet Kaur, Clemson U., akaur@g.clemson.edu
Address: Physics Department, 118 Kinard laboratory, Clemson, SC 29634-0978 United States

CoI: Marco Ajello, Clemson U.
CoI: Dieter H Hartmann, Clemson U.
CoI: Alberto Dominguez, Complutense University of Madrid
CoI: Arne Rau, Max Planck Institute for Extraterrestrial Physics, Germany
CoI: Jochen Greiner, Max Planck Institute for Extraterrestrial Physics, Germany
CoI: Patricia Schady, Max Planck Institute for Extraterrestrial Physics, Germany
CoI: Nuria Alvarez-Crespo, Osservatorio Astrofisico di Torino
CoI: Francesco Massaro, Osservatorio Astrofisico di Torino

Title: Spectroscopic confirmation of Fermi-LAT detected BL Lacs with known photometric redshifts

Abstract: Distant BL Lacertae (BL Lac) objects are excellent cosmological probes of the UV/optical/IR background (also known as extragalactic background light, EBL). Unfortunately obtaining redshift information is challenging to determine due to their featureless spectrum. We request textbf{21 hours (2 nights+ 3 hours}) with the Goodmann spectrograph on the 4~m SOAR telescope, Chile to obtain spectra for 17 BL Lacs detected with the {it Fermi}-LAT for which photometric upper limits are known ($z<1.3$). These proposed observations will provide lower limits through intervening absorption systems, thus establishing redshift ranges for all these sources. Because we expect most sources to have $z>0.7$, this program will deliver new constraints on the unknown EBL at $zsim 1$. The technique proposed here, which combines the photometric and spectroscopic method to yield upper and lower limits, respectively, is the only way to provide a redshift estimate for {it half} of the BL Lac population. {bf Time requested : 21 hours}

Program Type: Standard/Extragalactic

Scheduled Nights:
Run 1 (2017A):  SOAR/Goodman -- 1n on Feb 14 2017
Run 2 (2017A):  SOAR/Goodman -- 1n on May 14 2017
Run 3 (2017A):  SOAR/Goodman -- 0.5n on Jul 16 2017


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NOAO >   Observing Info >   Approved Programs >   2017A-0286

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