Connecting the Scales: Large Area High-resolution Ammonia Mapping of NGC 1333. (arXiv:1904.03359v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Dhabal_A/0/1/0/all/0/1">Arnab Dhabal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mundy_L/0/1/0/all/0/1">Lee G. Mundy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_C/0/1/0/all/0/1">Che-yu Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Teuben_P/0/1/0/all/0/1">Peter Teuben</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Storm_S/0/1/0/all/0/1">Shaye Storm</a>
We use NH3 inversion transitions to trace the dense gas in the NGC 1333
region of the Perseus molecular cloud. NH3(1,1) and NH3(2,2) maps covering an
area of 102 square arcminutes at an angular resolution of ~3.7″ are produced by
combining VLA interferometric observations with GBT single dish maps. The
combined maps have a spectral resolution of 0.14 km/s and a sensitivity of 4
mJy/beam. We produce integrated intensity maps, peak intensity maps and
dispersion maps of NH3(1,1) and NH3(2,2) and a line-of-sight velocity map of
NH3(1,1). These are used to derive the optical depth for the NH3(1,1) main
component, the excitation temperature of NH3(1,1), and the rotational
temperature, kinetic temperature and column density of NH3 over the mapped
area.
We compare these observations with the CARMA J=1-0 observations of N2H+ and
H13CO+ and conclude that they all trace the same material in these dense star
forming regions. From the NH3(1,1) velocity map, we find that a velocity
gradient ridge extends in an arc across the entire southern part of NGC 1333.
We propose that a large scale turbulent cell is colliding with the cloud, which
could result in the formation of a layer of compressed gas. This region along
the velocity gradient ridge is dotted with Class 0/I YSOs, that could have
formed from local overdensities in the compressed gas leading to gravitational
instabilities. The NH3(1,1) velocity dispersion map also has relatively high
values along this region, thereby substantiating the shock layer argument.
We use NH3 inversion transitions to trace the dense gas in the NGC 1333
region of the Perseus molecular cloud. NH3(1,1) and NH3(2,2) maps covering an
area of 102 square arcminutes at an angular resolution of ~3.7″ are produced by
combining VLA interferometric observations with GBT single dish maps. The
combined maps have a spectral resolution of 0.14 km/s and a sensitivity of 4
mJy/beam. We produce integrated intensity maps, peak intensity maps and
dispersion maps of NH3(1,1) and NH3(2,2) and a line-of-sight velocity map of
NH3(1,1). These are used to derive the optical depth for the NH3(1,1) main
component, the excitation temperature of NH3(1,1), and the rotational
temperature, kinetic temperature and column density of NH3 over the mapped
area.
We compare these observations with the CARMA J=1-0 observations of N2H+ and
H13CO+ and conclude that they all trace the same material in these dense star
forming regions. From the NH3(1,1) velocity map, we find that a velocity
gradient ridge extends in an arc across the entire southern part of NGC 1333.
We propose that a large scale turbulent cell is colliding with the cloud, which
could result in the formation of a layer of compressed gas. This region along
the velocity gradient ridge is dotted with Class 0/I YSOs, that could have
formed from local overdensities in the compressed gas leading to gravitational
instabilities. The NH3(1,1) velocity dispersion map also has relatively high
values along this region, thereby substantiating the shock layer argument.
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