Overview of the DESI Legacy Imaging Surveys
Authors: Dey Arjun , Schlegel David J. , Lang Dustin , Blum Robert , Burleigh Kaylan , Fan Xiaohui , Findlay Joseph R. , Finkbeiner Doug , Herrera David , Juneau Stéphanie , Landriau Martin , Levi Michael , McGreer Ian , Meisner Aaron , Myers Adam D. , Moustakas John , Nugent Peter , Patej Anna , Schlafly Edward F. , Walker Alistair R. , Valdes Francisco , Weaver Benjamin A. , Yèche Christophe , Zou Hu , Zhou Xu , Abareshi Behzad , Abbott T. M. C. , Abolfathi Bela , Aguilera C. , Alam Shadab , Allen Lori , Alvarez A. , Annis James , Ansarinejad Behzad , Aubert Marie , Beechert Jacqueline , Bell Eric F. , BenZvi Segev Y. , Beutler Florian , Bielby Richard M. , Bolton Adam S. , Briceño César , Buckley-Geer Elizabeth J. , Butler Karen , Calamida Annalisa , Carlberg Raymond G. , Carter Paul , Casas Ricard , Castander Francisco J. , Choi Yumi , Comparat Johan , Cukanovaite Elena , Delubac Timothée , DeVries Kaitlin , Dey Sharmila , Dhungana Govinda , Dickinson Mark , Ding Zhejie , Donaldson John B. , Duan Yutong , Duckworth Christopher J. , Eftekharzadeh Sarah , Eisenstein Daniel J. , Etourneau Thomas , Fagrelius Parker A. , Farihi Jay , Fitzpatrick Mike , Font-Ribera Andreu , Fulmer Leah , Gänsicke Boris T. , Gaztanaga Enrique , George Koshy , Gerdes David W. , A Gontcho Satya Gontcho , Gorgoni Claudio , Green Gregory , Guy Julien , Harmer Diane , Hernandez M. , Honscheid Klaus , Huang Lijuan (Wendy) , James David J. , Jannuzi Buell T. , Jiang Linhua , Joyce Richard , Karcher Armin , Karkar Sonia , Kehoe Robert , Kneib Jean-Paul, , Kueter-Young Andrea , Lan Ting-Wen , Lauer Tod R. , Guillou Laurent Le , Van Suu Auguste Le , Lee Jae Hyeon , Lesser Michael , Levasseur Laurence Perreault , Li Ting S. , Mann Justin L. , Marshall Robert , Martínez-Vázquez C. E. , Martini Paul , du Mas des Bourboux Hélion , McManus Sean , Meier Tobias Gabriel , Ménard Brice , Metcalfe Nigel , Muñoz-Gutiérrez Andrea , Najita Joan , Napier Kevin , Narayan Gautham , Newman Jeffrey A. , Nie Jundan , Nord Brian , Norman Dara J. , Olsen Knut A. G. , Paat Anthony , Palanque-Delabrouille Nathalie , Peng Xiyan , Poppett Claire L. , Poremba Megan R. , Prakash Abhishek , Rabinowitz David , Raichoor Anand , Rezaie Mehdi , Robertson A. N. , Roe Natalie A. , Ross Ashley J. , Ross Nicholas P. , Rudnick Gregory , Gaines Sasha , Saha Abhijit , Sánchez F. Javier , Savary Elodie , Schweiker Heidi , Scott Adam , Seo Hee-Jong , Shan Huanyuan , Silva David R. , Slepian Zachary , Soto Christian , Sprayberry David , Staten Ryan , Stillman Coley M. , Stupak Robert J. , Summers David L. , Tie Suk Sien , Tirado H. , Vargas-Magaña Mariana , Vivas A. Katherina , Wechsler Risa H. , Williams Doug , Yang Jinyi , Yang Qian , Yapici Tolga , Zaritsky Dennis , Zenteno A. , Zhang Kai , Zhang Tianmeng , Zhou Rongpu , Zhou Zhimin 
Published: April 2019

Abstract
The DESI Legacy Imaging Surveys (http://legacysurvey.org/) are a combination of three public projects (the Dark Energy Camera Legacy Survey, the Beijing–Arizona Sky Survey, and the Mayall z-band Legacy Survey) that will jointly image ≈14,000 deg2 of the extragalactic sky visible from the northern hemisphere in three optical bands (g, r, and z) using telescopes at the Kitt Peak National Observatory and the Cerro Tololo Inter-American Observatory. The combined survey footprint is split into two contiguous areas by the Galactic plane. The optical imaging is conducted using a unique strategy of dynamically adjusting the exposure times and pointing selection during observing that results in a survey of nearly uniform depth. In addition to calibrated images, the project is delivering a catalog, constructed by using a probabilistic inference-based approach to estimate source shapes and brightnesses. The catalog includes photometry from the grz optical bands and from four mid-infrared bands (at 3.4, 4.6, 12, and 22 μm) observed by the Wide-field Infrared Survey Explorer satellite during its full operational lifetime. The project plans two public data releases each year. All the software used to generate the catalogs is also released with the data. This paper provides an overview of the Legacy Surveys project.