The Astrophysical Journal (Jan 2023)
Target Selection and Sample Characterization for the DESI LOW-Z Secondary Target Program
- Elise Darragh-Ford,
- John F. Wu,
- Yao-Yuan Mao,
- Risa H. Wechsler,
- Marla Geha,
- Jaime E. Forero-Romero,
- ChangHoon Hahn,
- Nitya Kallivayalil,
- John Moustakas,
- Ethan O. Nadler,
- Marta Nowotka,
- J. E. G. Peek,
- Erik J. Tollerud,
- Benjamin Weiner,
- J. Aguilar,
- S. Ahlen,
- D. Brooks,
- A. P. Cooper,
- A. de la Macorra,
- A. Dey,
- K. Fanning,
- A. Font-Ribera,
- S. Gontcho A Gontcho,
- K. Honscheid,
- T. Kisner,
- Anthony Kremin,
- M. Landriau,
- Michael E. Levi,
- P. Martini,
- Aaron M. Meisner,
- R. Miquel,
- Adam D. Myers,
- Jundan Nie,
- N. Palanque-Delabrouille,
- W. J. Percival,
- F. Prada,
- D. Schlegel,
- M. Schubnell,
- Gregory Tarlé,
- M. Vargas-Magaña,
- Zhimin Zhou,
- H. Zou
Affiliations
- Elise Darragh-Ford
- ORCiD
- Kavli Institute for Particle Astrophysics and Cosmology and Department of Physics, Stanford University , Stanford, CA 94305, USA ; [email protected]; SLAC National Accelerator Laboratory , Menlo Park, CA 94025, USA
- John F. Wu
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA; Department of Physics & Astronomy, Johns Hopkins University , 3400 North Charles Street, Baltimore, MD 21218, USA
- Yao-Yuan Mao
- ORCiD
- Department of Physics and Astronomy, University of Utah , Salt Lake City, UT 84112, USA
- Risa H. Wechsler
- ORCiD
- Kavli Institute for Particle Astrophysics and Cosmology and Department of Physics, Stanford University , Stanford, CA 94305, USA ; [email protected]; SLAC National Accelerator Laboratory , Menlo Park, CA 94025, USA
- Marla Geha
- ORCiD
- Department of Astronomy, Yale University , New Haven, CT 06520, USA
- Jaime E. Forero-Romero
- ORCiD
- Departamento de Física, Universidad de los Andes , Cra. 1 No. 18A-10, Bogotá, Colombia; Observatorio Astronómico, Universidad de los Andes , Cra. 1 No. 18A-10, Bogotá, Colombia
- ChangHoon Hahn
- ORCiD
- Department of Astrophysical Sciences, Princeton University , Peyton Hall, Princeton, NJ 08544, USA; Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- Nitya Kallivayalil
- ORCiD
- University of Virginia , Department of Astronomy, 530 McCormick Road, Charlottesville, VA 22904, USA
- John Moustakas
- ORCiD
- Department of Physics and Astronomy, Siena College , 515 Loudon Road, Loudonville, NY 12211, USA
- Ethan O. Nadler
- ORCiD
- Carnegie Observatories , 813 Santa Barbara Street, Pasadena, CA 91101, USA; Department of Physics & Astronomy, University of Southern California , Los Angeles, CA, 90007, USA
- Marta Nowotka
- Kavli Institute for Particle Astrophysics and Cosmology and Department of Physics, Stanford University , Stanford, CA 94305, USA ; [email protected]; SLAC National Accelerator Laboratory , Menlo Park, CA 94025, USA
- J. E. G. Peek
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA; Department of Physics & Astronomy, Johns Hopkins University , 3400 North Charles Street, Baltimore, MD 21218, USA
- Erik J. Tollerud
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Benjamin Weiner
- ORCiD
- Department of Astronomy and Steward Observatory, University of Arizona , Tucson, AZ 85721, USA
- J. Aguilar
- ORCiD
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- S. Ahlen
- ORCiD
- Physics Dept., Boston University , 590 Commonwealth Avenue, Boston, MA 02215, USA
- D. Brooks
- ORCiD
- Department of Physics & Astronomy, University College London , Gower Street, London, WC1E 6BT, UK
- A. P. Cooper
- ORCiD
- Institute of Astronomy and Department of Physics, National Tsing Hua University , 101 Kuang-Fu Road Sec. 2, Hsinchu 30013, Taiwan
- A. de la Macorra
- Instituto de Física, Universidad Nacional Autónoma de México , Cd. de México C.P. 04510, México
- A. Dey
- ORCiD
- NSF’s NOIRLab , 950 N. Cherry Avenue, Tucson, AZ 85719, USA
- K. Fanning
- Department of Physics, University of Michigan , Ann Arbor, MI48109, USA
- A. Font-Ribera
- ORCiD
- Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology , Campus UAB, E-08193 Bellaterra Barcelona, Spain
- S. Gontcho A Gontcho
- ORCiD
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- K. Honscheid
- Center for Cosmology and AstroParticle Physics, The Ohio State University , 191 West Woodruff Avenue, Columbus, OH 43210, USA; Department of Physics, The Ohio State University , 191 West Woodruff Avenue, Columbus, OH 43210, USA
- T. Kisner
- ORCiD
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- Anthony Kremin
- ORCiD
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- M. Landriau
- ORCiD
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- Michael E. Levi
- ORCiD
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- P. Martini
- ORCiD
- Center for Cosmology and AstroParticle Physics, The Ohio State University , 191 West Woodruff Avenue, Columbus, OH 43210, USA; Department of Astronomy, The Ohio State University , 4055 McPherson Laboratory, 140 W 18th Avenue, Columbus, OH 43210, USA
- Aaron M. Meisner
- ORCiD
- NSF’s NOIRLab , 950 N. Cherry Avenue, Tucson, AZ 85719, USA
- R. Miquel
- ORCiD
- Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology , Campus UAB, E-08193 Bellaterra Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats , Passeig de Lluís Companys, 23, E-08010 Barcelona, Spain
- Adam D. Myers
- Department of Physics & Astronomy, University of Wyoming , 1000 E. University, Dept. 3905, Laramie, WY 82071, USA
- Jundan Nie
- ORCiD
- National Astronomical Observatories, Chinese Academy of Sciences , A20 Datun Road, Chaoyang District, Beijing, 100012, People's Republic of China
- N. Palanque-Delabrouille
- ORCiD
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA; IRFU, CEA, Université Paris-Saclay , F-91191 Gif-sur-Yvette, France
- W. J. Percival
- ORCiD
- Department of Physics and Astronomy, University of Waterloo , 200 University Avenue W, Waterloo, ON N2L 3G1, Canada; Perimeter Institute for Theoretical Physics , 31 Caroline Street North, Waterloo, ON N2L 2Y5, Canada; Waterloo Centre for Astrophysics, University of Waterloo , 200 University Avenue W, Waterloo, ON N2L 3G1, Canada
- F. Prada
- ORCiD
- Instituto de Astrofísica de Andalucía (CSIC) , Glorieta de la Astronomía, s/n, E-18008 Granada, Spain
- D. Schlegel
- ORCiD
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- M. Schubnell
- Department of Physics, University of Michigan , Ann Arbor, MI48109, USA; University of Michigan , Ann Arbor, MI 48109, USA
- Gregory Tarlé
- ORCiD
- University of Michigan , Ann Arbor, MI 48109, USA
- M. Vargas-Magaña
- Instituto de Física, Universidad Nacional Autónoma de México , Cd. de México C.P. 04510, México
- Zhimin Zhou
- ORCiD
- National Astronomical Observatories, Chinese Academy of Sciences , A20 Datun Road, Chaoyang District, Beijing, 100012, People's Republic of China
- H. Zou
- ORCiD
- National Astronomical Observatories, Chinese Academy of Sciences , A20 Datun Road, Chaoyang District, Beijing, 100012, People's Republic of China
- DOI
- https://doi.org/10.3847/1538-4357/ace902
- Journal volume & issue
-
Vol. 954,
no. 2
p. 149
Abstract
We introduce the DESI LOW- Z Secondary Target Survey, which combines the wide-area capabilities of the Dark Energy Spectroscopic Instrument (DESI) with an efficient, low-redshift target selection method. Our selection consists of a set of color and surface brightness cuts, combined with modern machine-learning methods, to target low-redshift dwarf galaxies ( z < 0.03) between 19 < r < 21 with high completeness. We employ a convolutional neural network (CNN) to select high-priority targets. The LOW- Z survey has already obtained over 22,000 redshifts of dwarf galaxies ( M _* < 10 ^9 M _⊙ ), comparable to the number of dwarf galaxies discovered in the Sloan Digital Sky Survey DR8 and GAMA. As a spare fiber survey, LOW- Z currently receives fiber allocation for just ∼50% of its targets. However, we estimate that our selection is highly complete: for galaxies at z < 0.03 within our magnitude limits, we achieve better than 95% completeness with ∼1% efficiency using catalog-level photometric cuts. We also demonstrate that our CNN selections z < 0.03 galaxies from the photometric cuts subsample at least 10 times more efficiently while maintaining high completeness. The full 5 yr DESI program will expand the LOW- Z sample, densely mapping the low-redshift Universe, providing an unprecedented sample of dwarf galaxies, and providing critical information about how to pursue effective and efficient low-redshift surveys.
Keywords
