Preprint / Version 0

The Green Bank Ammonia Survey: Data Release 2

Authors

  • Jaime E. Pineda
  • Rachel K. Friesen
  • Erik Rosolowsky
  • Ana Chacón-Tanarro
  • Michael Chun-Yuan Chen
  • James Di Francesco
  • Helen Kirk
  • Anna Punanova
  • Youngmin Seo
  • Yancy Shirley
  • Adam Ginsburg
  • Stella S. R. Offner
  • Ayush Pandhi
  • Ayushi Singh
  • Feiyu Quan
  • Héctor G. Arce
  • Paola Caselli
  • Spandan Choudhury
  • Alyssa A. Goodman
  • Fabian Heitsch
  • Peter G. Martin
  • Christopher D. Matzner
  • Philip C. Myers
  • Elena Redaelli
  • Samantha Scibelli

Abstract

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 $A_\mathrm{V} \gtrsim 7$~mag visible from the northern hemisphere in emission from NH$_3$ 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, IC348, 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 (CrA) East and West; IC5146; and Serpens Aquila and MWC297 in Serpens. Similar to what was presented in GAS DR1, we find that the NH$_3$ emission and dust continuum emission from Herschel correspond closely. We find that the NH$_3$ 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 non-thermal velocity dispersions. We produce maps of the gas kinematics, temperature, and NH$_3$ column densities through forward modeling of the hyperfine structure of the NH$_3$ (1,1) and (2,2) lines. We show that the NH$_3$ velocity dispersion, $σ_v$, and gas kinetic temperature, $T_{\rm kin}$, vary systematically between the regions included in this release, with an increase in both the mean value and spread of $σ_v$ and $T_{\rm kin}$ with increasing star formation activity. The data presented in this paper are publicly available via \dataset[DOI: 10.11570/24.0091]{https://doi.org/10.11570/24.0091}.

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Posted

2025-10-12