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Related papers: Mid- and high-J CO observations towards UCHIIs

200 papers

The C$_2$H $N=1-0$ transition was used to investigate the possible line of sight sub-structures from the dense and optically thick in $^{13}$CO $J=1-0$ regions in the Ophiuchus star forming molecular cloud. With a 0.2 K or lower noise,…

Astrophysics of Galaxies · Physics 2025-03-13 Lei qian , Zhichen Pan , Dongyue Jiang , Zichen Huang

We present high-frequency (18-24 GHz) radio continuum observations towards 335 methanol masers, excellent signposts for young, embedded high-mass protostars. These complete the search for hypercompact HII (HCHII) regions towards young…

Astrophysics of Galaxies · Physics 2025-06-04 A. L. Patel , J. S. Urquhart , A. Y. Yang , L. K. Morgan , K. M. Menten , M. A. Thompson , T. Moore , I. Grozdanova , S. Khan , T. Csengeri

CO isotopes are able to probe the different components in protostellar clouds. These components, core, envelope and outflow have distinct physical conditions and sometimes more than one component contributes to the observed line profile. In…

Astrophysics · Physics 2007-11-27 P. B. Carolan , M. P. Redman , E. Keto , J. M. C. Rawlings

Observations of dark cloud cores have been carried out in the mid-infrared using ISOCAM and in the far-infrared using ISOPHOT, both aboard the Infrared Space Observatory. The cores are in most cases detected in emission at 200 and 170…

Astrophysics · Physics 2007-05-23 Aurore Bacmann , Philippe Andre , Derek Ward-Thompson

We present the results of an extensive observational study of the active star-forming complex W51 that was observed in the J=2-1 transition of the 12CO and 13CO molecules over a 1.25 deg x 1.00 deg region with the University of Arizona…

Astrophysics of Galaxies · Physics 2015-05-19 Miju Kang , John H. Bieging , Craig A. Kulesa , Youngung Lee , Minho Choi , William L. Peters

We observed a 10x20 pc region of the molecular cloud M17 in the 12CO and 13CO J=3-2 and J=2-1 transitions to determine their global behavior and to assess the reliability of using ratios of CO line intensities integrated over an entire…

Astrophysics · Physics 2009-10-31 C. D. Wilson , J. E. Howe , M. L. Balogh

Atacama Pathfinder Experiment (APEX) mapping observations in CO (9-8) and (4-3) toward a high-mass star-forming region, NGC 6334 I, are presented. The CO (9-8) map has a 6.4 arcsec resolution, revealing a ~0.5 pc, jet-like, and bipolar…

Astrophysics of Galaxies · Physics 2015-06-03 Keping Qiu , Friedrich Wyrowski , Karl M. Menten , Rolf Guesten , Silvia Leurini , Christian Leinz

During the embedded stage of star formation, bipolar molecular outflows and UV radiation from the protostar are important feedback processes. Our aim is to quantify the feedback, mechanical and radiative, for a large sample of low-mass…

Ultracompact HII regions are signposts of massive star formation and their properties provide diagnostics for the characteristics of very young O stars embedded in molecular clouds. While radio observations have given us a good picture of…

Astrophysics · Physics 2009-11-10 D. T. Jaffe , Q. Zhu , J. H. Lacy , M. J. Richter , T. K. Greathouse

We present results of a multi-line study of the filamentary infrared dark cloud G351.78-0.54 in the 1.3 and 0.8 mm wavelength bands. The lines of the three isotopologues of carbon monoxide CO, N$_2$H$^+$, CH$_3$CCH and HNCO were observed.…

Astrophysics of Galaxies · Physics 2021-05-10 O. L. Ryabukhina , I. I. Zinchenko

We report the detection of far-infrared (FIR) CO rotational emission from nearby active galactic nuclei (AGN) and starburst galaxies, as well as several merging systems and Ultra-Luminous Infrared Galaxies (ULIRGs). Using Herschel-PACS, we…

We present results from a sample of 106 high-luminosity IRAS sources observed with the Very Large Array in the B and C configurations. 96 sources were observed in the X-band and 52 in the K-band, with 42 of them observed at both…

Astrophysics of Galaxies · Physics 2023-06-16 D. Quiroga-Gonzalez , M. A. Trinidad , E. de la Fuente , J. M. Masque , T. Rodriguez-Esnard

We present a fully sampled map covering the Orion Hot Core and dense molecular ridge, in the sub-millimeter J=6-5 rotational transition of 13CO, at 0.45 mm with a resolution of 13 arcsec and 0.5 km s^-1. The map covers 3 arc min by 2arc min…

Solar and Stellar Astrophysics · Physics 2015-05-20 T. L. Wilson , D. Muders , M. Dumke , C. Henkel , Jonathan H. Kawamura

The evolution of deeply embedded young stellar objects (YSOs) has traditionally been traced through dust continuum spectral energy distributions (SEDs), but the use of CO excitation as an evolutionary probe has not yet been explored due to…

We present a pilot survey of 21 lines of sight towards UCHII regions in the H2CO 1-1 (6cm) and 2-2 (2cm) transitions, using the H2CO centimeter lines as a molecular gas densitometer. Using Arecibo and Green Bank beam-matched observations,…

Astrophysics of Galaxies · Physics 2011-07-27 Adam Ginsburg , Jeremy Darling , Cara Battersby , Ben Zeiger , John Bally

(Abridged) Massive stellar embryos are embedded in warm envelopes that provide mass reservoirs for the accretion process onto final stars. Feedback from star formation activities in return impacts the properties of the envelopes, offering…

Astrophysics of Galaxies · Physics 2025-03-12 Thanh Dat Hoang , Min-Young Lee , Friedrich Wyrowski , Agata Karska , Felipe Navarete , Karl M. Menten

We present observations of the nearby spiral galaxy IC342 with the Herschel Spectral and Photometric Imaging Receiver (SPIRE) Fourier Transform Spectrometer. The spectral range afforded by SPIRE, 196-671 microns, allows us to access a…

We present radio and infrared observations of 4 hyper-compact HII regions and 4 ultra-compact HII regions in the southern Galactic plane. These objects were selected from a blind survey for UCHII regions using data from two new radio…

Astrophysics of Galaxies · Physics 2015-05-18 Tara Murphy , Martin Cohen , Ronald D. Ekers , Anne J. Green , Robin Wark , Vanessa Moss

Aims:To obtain insight into the physical structure of the warm gas in the inner envelope of protostars and the interaction with the outflow. Methods: Sub-millimeter observations of 12CO, 13CO and/or C18O in J=3-2, J=4-3 and J=7-6 were…

This paper presents CI, CO J=4-3, and CO J=3-2 maps of the barred spiral galaxy M83 taken at the James Clerk Maxwell Telescope. Observations indicate a double peaked structure which is consistent with gas inflow along the bar collecting at…

Astrophysics · Physics 2009-10-30 Glen R. Petitpas , Christine D. Wilson