APOGEE Ancillary Targets

Spectra for ancillary targets are available in the same manner as any other SDSS spectra: individually through the DR10 SkyServer Navigate and Explore tools, and collectively through SkyServer search tools, the CasJobs batch interface, or the Science Archive Server Advanced Search.

Ancillary Target Flags

For all SDSS-III spectroscopic data, information about how that object was targeted for spectroscopy is included in the object's Target Flags. Information about whether a target was selected for one or more ancillary target programs is included in the flags APOGEE_TARGET1 and APOGEE_TARGET2. (These parameters, like all SDSS flag data, are stored as bitmasks. For more information on how to work with such data, see the description of SDSS-III bitmasks).

Ancillary Target Selection

This page describes APOGEE's ancillary targets in general; the pages linked from the list below describe how targets were selected for specific ancillary targeting programs.

Ancillary targets were requested in two calls for proposals made to the SDSS-III collaboration: one in 2011 and one in 2012. DR10 includes targets from proposals accepted in the first call; additional targets from these and from the second-call proposals will be included in future data releases (see Zasowski et al. (2013) for a description of the second-call programs).

Ancillary programs range from those that just use a few fibers on already-planned APOGEE fields to some that involve entirely new plates. The fraction of ancillary targets per field thus ranges from 0-100% (but is generally very small, except for the dedicated "new" fields). Fibers were alloted such that ancillary targets use approximately 5% of APOGEE's total fiber-visits. Ancillary targets were given high priority on plates, above the main survey sample, because of their small numbers and high science impact.

DR10 Ancillary Science Programs

The DR10 documentation includes an index of the values of APOGEE_TARGET1 and APOGEE_TARGET2 that correspond to each ancillary target program.