Probing ISM Structure in Trumpler 14 & Carina I Using The Stratospheric Terahertz Observatory 2

We present observations of the Trumpler 14/Carina I region carried out using the Stratospheric Terahertz Observatory 2 (STO2). The Trumpler 14/Carina I region is in the west part of the Carina Nebula Complex, which is one of the most extreme star-forming regions in the Milky Way. We observed Trumpler 14/Carina I in the 158 $\mu$m transition of [C\,{\sc ii}] with a spatial resolution of 48$''$ and a velocity resolution of 0.17 km s$^{-1}$. The observations cover a 0.25$^\circ$ by 0.28$^\circ$ area with central position {\it l} = 297.34$^\circ$, {\it b} = -0.60$^\circ$. The kinematics show that bright [C\,{\sc ii}] structures are spatially and spectrally correlated with the surfaces of CO clouds, tracing the photodissociation region and ionization front of each molecular cloud. Along 7 lines of sight that traverse Tr 14 into the dark ridge to the southwest, we find that the [C\,{\sc ii}] luminosity from the HII region is 3.7 times that from the PDR. In same los we find in the PDRs an average ratio of 1:4.1:5.6 for the mass in atomic gas:dark-CO gas: molecular gas traced by CO. Comparing multiple gas tracers including HI 21cm, [C\,{\sc ii}], CO, and radio recombination lines, we find that the HII regions of the Carina Nebula Complex are well-described as HII regions with one-side freely expanding towards us, consistent with the champagne model of ionized gas evolution. The dispersal of the GMC in this region is dominated by EUV photoevaporation; the dispersal timescale is 20-30 Myr.Comment: ApJ accepte

Extended red(dened) regions in 2MASS

VizieR online Data Catalogue associated with article published in journal Astronomy & Astrophysics with title 'Searching for dark clouds in the outer galactic plane. I. A statistical approach for identifying extended red(dened) regions in 2MASS.' (bibcode: 2010A&A...515A..51F

Early stages of star formation in IRDCs

VizieR online Data Catalogue associated with article published in journal Astronomical Journal (AAS) with title 'The early stages of star formation in infrared dark clouds: characterizing the core dust properties.' (bibcode: 2010ApJ...715..310R

Perpendicular HF map to the Orion Bar

VizieR online Data Catalogue associated with article published in journal Astronomy & Astrophysics with title 'Origin of hydrogen fluoride emission in the Orion Bar. An excellent tracer for CO-dark H_2_ gas clouds.' (bibcode: 2019A&A...631A.117K

19 highmass SFR Herschel spectra and maps

VizieR online Data Catalogue associated with article published in journal Astronomy & Astrophysics with title 'Multi line Herschel HIFI observations of water reveal infall motions and chemical segregation around high mass protostars.' (bibcode: 2019A&A...625A.103V

Molecular lines in 4 IRCS clumps

VizieR online Data Catalogue associated with article published in journal Astronomy & Astrophysics with title 'The physical conditions in IRDC clumps from Herschel/HIFI observations of H_2_O.' (bibcode: 2014A&A...570A..51S

Probing ISM Structure in Trumpler 14 and Carina i Using the Stratospheric Terahertz Observatory 2

We present observations of the Trumpler 14/Carina I region carried out using the Stratospheric Terahertz Observatory 2. The Trumpler 14/Carina I region is in the western part of the Carina Nebula Complex (CNC), which is one of the most extreme star-forming regions in the Milky Way. We observed Trumpler 14/Carina I in the 158 μm transition of [C ii] with a spatial resolution of 48″ and a velocity resolution of 0.17 km s-1. The observations cover a 0.25 by 0.28 area with central position l = 297.34, b = -0.60. The kinematics show that bright [C ii] structures are spatially and spectrally correlated with the surfaces of CO clouds, tracing the photodissociation region (PDR) and ionization front of each molecular cloud. Along seven lines of sight (LOSs) that traverse Tr 14 into the dark ridge to the southwest, we find that the [C ii] luminosity from the H ii region is 3.7 times that from the PDR. In the same LOS, we find in the PDRs an average ratio of 1 : 4.1 : 5.6 for the mass in atomic gas : dark CO gas : molecular gas traced by CO. Comparing multiple gas tracers, including H i 21 cm, [C ii], CO, and radio recombination lines, we find that the H ii regions of the CNC are well described as H ii regions with one side freely expanding toward us, consistent with the Champagne model of ionized gas evolution. The dispersal of the GMC in this region is dominated by EUV photoevaporation; the dispersal timescale is 20-30 Myr.QN/Gao La

Interstellar OH+ , H2O+ and H3O+ along the sight-line to G10.6-0.4

We report the detection of absorption lines by the reactive ions OH+, H2O+ and H3O+ along the line of sight to the submillimeter continuum source G10.6$-$0.4 (W31C). We used the Herschel HIFI instrument in dual beam switch mode to observe the ground state rotational transitions of OH+ at 971~GHz, H2O+ at 1115 and 607~GHz, and H3O+ at 984 GHz. The resultant spectra show deep absorption over a broad velocity range that originates in the interstellar matter along the line of sight to G10.6$-$0.4 as well as in the molecular gas directly associated with that source. The OH+ spectrum reaches saturation over most velocities corresponding to the foreground gas, while the opacity of the H2O+ lines remains lower than 1 in the same velocity range, and the H3O+ line shows only weak absorption. For LSR velocities between 7 and 50 kms$^{-1}$ we estimate total column densities of $N$(OH+) $> 2.5 \times 10^{14}$ cm$^{-2}$, $N$(H2O+) $\sim 6 \times 10^{13}$ cm$^{-2}$ and $N$(H3O+) $\sim 4.0 \times 10^{13}$ cm$^{-2}$. These detections confirm the role of O$^+$ and OH$^+$ in initiating the oxygen chemistry in diffuse molecular gas and strengthen our understanding of the gas phase production of water. The high ratio of the OH+ by the H2O+ column density implies that these species predominantly trace low-density gas with a small fraction of hydrogen in molecular form