The Green Bank Ammonia Survey (GAS): First Results of NH3 mapping the Gould Belt
| Autor: | Friesen, Rachel K., Pineda, Jaime E., Rosolowsky, Erik, Alves, Felipe, Chacón-Tanarro, Ana, Chen, Hope How-Huan, Chen, Michael Chun-Yuan, Di Francesco, James, Keown, Jared, Kirk, Helen, Punanova, Anna, Seo, Youngmin, Shirley, Yancy, Ginsburg, Adam, Hall, Christine, Offner, Stella S. R., Singh, Ayushi, Arce, Héctor G., Caselli, Paola, Goodman, Alyssa A., Martin, Peter G., Matzner, Christopher, Myers, Philip C., Redaelli, Elena |
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| Rok vydání: | 2017 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.3847/1538-4357/aa6d58 |
| Popis: | 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 $A_V \gtrsim 7$ mag visible from the northern hemisphere in emission from NH$_3$ and other key molecular tracers. This first release includes the data for four regions in Gould Belt clouds: B18 in Taurus, NGC 1333 in Perseus, L1688 in Ophiuchus, and Orion A North in Orion. We compare the NH$_3$ emission to dust continuum emission from Herschel, and find that the two tracers correspond closely. NH$_3$ is present in over 60\% of lines-of-sight with $A_V \gtrsim 7$ mag in three of the four DR1 regions, in agreement with expectations from previous observations. The sole exception is B18, where NH$_3$ is detected toward ~ 40\% of lines-of-sight with $A_V \gtrsim 7$ mag. Moreover, we find that the NH$_3$ emission is generally extended beyond the typical 0.1 pc length scales of dense cores. 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, ${\sigma}_v$, and gas kinetic temperature, $T_K$, vary systematically between the regions included in this release, with an increase in both the mean value and spread of ${\sigma}_v$ and $T_K$ with increasing star formation activity. The data presented in this paper are publicly available. Comment: 33 pages, 27 figures, accepted to ApJS. Datasets are publicly available: https://dataverse.harvard.edu/dataverse/GAS_DR1 |
| Databáze: | arXiv |
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