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High Energy Blazars and Optical Counterparts of Gamma-ray Sources


A search for the optical counterparts of Fermi gamma-ray source in a 7,650 square degree area of sky

Finding Targets

An object whose ANCILLARY_TARGET1 value include one or more of the bitmasks in the following table was targeted for spectroscopy as part of this ancillary target program. See SDSS-III bitmasks to learn how to use these values to identify objects in this ancillary target program.

(bit name)
Bit number Target density
BLAZGX 52 0.01
BLAZGXR 54 0.03
BLAZXR 55 0.11


We targeted candidate optical counterparts of sources detected (or likely to be detected) by NASA's Fermi Gamma-ray Space Telescope (Atwood et al. 2009), with the goal to spectroscopically confirm and provide redshifts for candidate gamma-ray blazars.

Primary contact

Scott Anderson
University of Washington
anderson -at-

Other contacts

Toby Burnett

Target selection details

We require:

Ranked in approximate order of priority, fibers are assigned to targets from the following subprograms:

In addition, there were ten miscellaneous candidate blazar spectra taken in an early trial of this program. These targets were assigned subcategory names using the following flags: BLAZGVAR, BLAZR, and BLAZXRSAM.


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Voges, W., et al., 2000, IAU Circ., 7432, 1
Healey, S. E., et al, 2007, ApJS, 171, 61 doi:10.1086/513742
Richards, G. T., et al., 2009, ApJS, 180, 67 doi:10.1088/0067-0049/180/1/67
Schneider, D. P., et al., 2010, AJ, 139, 2360 doi:10.1088/0004-6256/139/6/2360
Anderson, S. F., et al., 2003, AJ, 126, 2209 doi:10.1086/378999
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