The Green Bank Ammonia Survey: Data Release 2
Journal article, 2026
We present an overview of the final data release (DR2) from the Green Bank Ammonia Survey (GAS). GAS is a large program at the Green Bank Telescope to map all Gould Belt star-forming regions with AV greater than or similar to 7 mag visible from the Northern Hemisphere in emission from NH3 and other key molecular tracers. This final release includes the data for all the regions observed: Heiles Cloud 2 and B18 in Taurus; Barnard 1, Barnard 1-E, IC 348, NGC 1333, L1448, L1451, and Per7/34 in Perseus; L1688 and L1689 in Ophiuchus; Orion A (North and South) and Orion B in Orion; Cepheus; B59 in Pipe; Corona Australis East and West; IC 5146; and Serpens Aquila and MWC297 in Serpens. Similar to what was presented in GAS DR1, we find that the NH3 emission and dust continuum emission from Herschel correspond closely. We find that the NH3 emission is generally extended beyond the typical 0.1 pc length scales of dense cores, and we find that the transition between coherent core and turbulent cloud is a common result. This shows that the regions of coherence are common throughout different star-forming regions, with a substantial fraction of the high column density regions displaying subsonic nonthermal velocity dispersions. We produce maps of the gas kinematics, temperature, and NH3 column densities through forward modeling of the hyperfine structure of the NH3 (1,1) and (2,2) lines. We show that the NH3 velocity dispersion, sigma v, and gas kinetic temperature, TK, vary systematically between the regions included in this release, with an increase in both the mean value and spread of sigma v and TK with increasing star formation activity. The data presented in this paper are publicly available via doi:10.11570/24.0091.
Author
Jaime E. Pineda
Max Planck Society
Rachel K. Friesen
University of Toronto
Erik Rosolowsky
University of Alberta
Ana Chacon-Tanarro
Spanish National Geographic Institute
Michael Chun-Yuan Chen
Queen's University
James Di Francesco
University of Victoria
National Research Council Canada
Helen Kirk
National Research Council Canada
University of Victoria
Anna Punanova
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Youngmin Seo
University of Arizona
Yancy Shirley
University of Arizona
Adam Ginsburg
University of Florida
Stella S. R. Offner
University of Texas
Ayush Pandhi
University of Toronto
Ayushi Singh
Sidrat Research
Feiyu Quan
University of Cambridge
Hector G. Arce
Yale University
Paola Caselli
Max Planck Society
Spandan Choudhury
Korea Astronomy and Space Science Institute
Max Planck Society
Alyssa A. Goodman
Harvard-Smithsonian Center for Astrophysics
Fabian Heitsch
The University of North Carolina System
Peter G. Martin
University of Toronto
Christopher D. Matzner
University of Toronto
Philip C. Myers
Harvard-Smithsonian Center for Astrophysics
Elena Redaelli
European Southern Observatory Santiago
Max Planck Society
Samantha Scibelli
National Radio Astronomy Observatory
Astrophysical Journal, Supplement Series
0067-0049 (ISSN) 1538-4365 (eISSN)
Vol. 282 1 18Subject Categories (SSIF 2025)
Astronomy, Astrophysics, and Cosmology
DOI
10.3847/1538-4365/ae11b1