Final Targeting Strategy for the Sloan Digital Sky Survey IV Apache Point Observatory Galactic Evolution Experiment 2 North Survey

Rachael L. Beaton, Ryan J. Oelkers, Christian R. Hayes, Kevin R. Covey, S. D. Chojnowski, Nathan De Lee, Jennifer S. Sobeck, Steven R. Majewski, Roger E. Cohen, José Fernández-Trincado, Penélope Longa-Pea, Julia E. O'Connell, Felipe A. Santana, Guy S. Stringfellow, Gail Zasowski, Conny Aerts, Borja Anguiano, Chad Bender, Caleb I. Caas, Katia CunhaJohn Donor, Scott W. Fleming, Peter M. Frinchaboy, Diane Feuillet, Paul Harding, Sten Hasselquist, Jon A. Holtzman, Jennifer A. Johnson, Juna A. Kollmeier, Marina Kounkel, Suvrath Mahadevan, Adrian M. Price-Whelan, Alvaro Rojas-Arriagada, Carlos Román-Zúiga, Edward F. Schlafly, Mathias Schultheis, Matthew Shetrone, Joshua D. Simon, Keivan G. Stassun, Amelia M. Stutz, Jamie Tayar, Johanna Teske, Andrew Tkachenko, Nicholas Troup, Franco D. Albareti, Dmitry Bizyaev, Jo Bovy, Adam J. Burgasser, Johan Comparat, Juan José Downes, Doug Geisler, Laura Inno, Arturo Manchado, Melissa K. Ness, Marc H. Pinsonneault, Francisco Prada, Alexandre Roman-Lopes, Gregory V.A. Simonian, Verne V. Smith, Renbin Yan, Olga Zamora

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45 Scopus citations


The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is a dual-hemisphere, near-infrared (NIR), spectroscopic survey with the goal of producing a chemodynamical mapping of the Milky Way. The targeting for APOGEE-2 is complex and has evolved with time. In this paper, we present the updates and additions to the initial targeting strategy for APOGEE-2N presented in Zasowski et al. (2017). These modifications come in two implementation modes: (i) "Ancillary Science Programs"competitively awarded to Sloan Digital Sky Survey IV PIs through proposal calls in 2015 and 2017 for the pursuit of new scientific avenues outside the main survey, and (ii) an effective 1.5 yr expansion of the survey, known as the Bright Time Extension (BTX), made possible through accrued efficiency gains over the first years of the APOGEE-2N project. For the 23 distinct ancillary programs, we provide descriptions of the scientific aims, target selection, and how to identify these targets within the APOGEE-2 sample. The BTX permitted changes to the main survey strategy, the inclusion of new programs in response to scientific discoveries or to exploit major new data sets not available at the outset of the survey design, and expansions of existing programs to enhance their scientific success and reach. After describing the motivations, implementation, and assessment of these programs, we also leave a summary of lessons learned from nearly a decade of APOGEE-1 and APOGEE-2 survey operations. A companion paper, F. Santana et al. (submitted; AAS29036), provides a complementary presentation of targeting modifications relevant to APOGEE-2 operations in the Southern Hemisphere.

Original languageEnglish (US)
Article number302
JournalAstronomical Journal
Issue number6
StatePublished - Dec 1 2021

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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