The Green Bank Ammonia Survey: First Results of NH3 Mapping of the Gould Belt

Rachel K. Friesen, Jaime E. Pineda, Erik Rosolowsky, Felipe Alves, Ana Chacón-Tanarro, Hope How Huan Chen, Michael Chun Yuan Chen, James Di Francesco, Jared Keown, Helen Kirk, Anna Punanova, Youngmin Seo, Yancy Shirley, Adam Ginsburg, Christine Hall, Stella S.R. Offner, Ayushi Singh, Héctor G. Arce, Paola Caselli, Alyssa A. GoodmanPeter G. Martin, Christopher Matzner, Philip C. Myers, Elena Redaelli

Research output: Contribution to journalReview articlepeer-review

83 Scopus citations


We present an overview of the first data release (DR1) and first-look science 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 ≳ 7 mag visible from the northern hemisphere in emission from NH3 and other key molecular tracers. his first release includes the data for four regions in the ould Belt clouds: B18 in Taurus, NGC 1333 in Perseus, 1688 in Ophiuchus, and Orion A North in Orion. We compare the NH3 emission to dust continuum emission rom Herschel and find that the two tracers correspond closely. We find that NH3 is present in over 60% of the lines of sight with AV ≳ 7 mag in three of the four DR1 regions, in agreement with expectations from previous observations. The sole exception is B18, where NH3 is detected toward ∼40% of the lines of sight with AV ≳ 7 mag. Moreover, we find that the NH3 emission is generally extended beyond the typical 0.1 pc length scales of dense cores. 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, sv, and gas kinetic temperature, TK, vary systematically between the regions included in this release, with an increase in both the mean value and the spread of sv and TK with increasing star formation activity. The data presented in this paper are publicly available (

Original languageEnglish (US)
Article number63
JournalAstrophysical Journal
Issue number1
StatePublished - Jul 1 2017


  • ISM: individual objects (L1668, B18, OrionA molecular complex, NGC1333)
  • ISM: molecules
  • Stars: formation

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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