scholarly journals Large-scale CO observations of a far-infrared loop in Pegasus; detection of a large number of very small molecular clouds possibly formed via shocks

2006 ◽  
Vol 2 (S237) ◽  
pp. 500-500
Author(s):  
Hiroaki Yamamoto ◽  
Akiko Kawamura ◽  
Kengo Tachihara ◽  
Norikazu Mizuno ◽  
Toshikazu Onishi ◽  
...  
Keyword(s):  
Molecular Clouds ◽  
Large Scale ◽  
Far Infrared ◽  
Grid Spacing ◽  
Angular Extent ◽  
Co Observations

Large-scale CO observations with the millimeter/submillimeter telescope NANTEN toward a whole FIR loop-like structure whose angular extent is ~20° × 20° around (l, b) ~(109°, − 45°) in Pegasus have been carried out in the 12CO (J = 1 − 0) at 4′ – 8′ grid spacing and the 12CO emitting region in the 13CO (J=1–0) at 2′ grid spacing. The diameter corresponds to ~25 pc at a distance of 100 pc, adopted from that of the star HD886(B2IV) near the center of the loop.

scholarly journals Large‐Scale CO Observations of a Far‐Infrared Loop in Pegasus: Detection of a Large Number of Very Small Molecular Clouds Possibly Formed via Shocks

2006 ◽  
Vol 642 (1) ◽  
pp. 307-318 ◽  
Author(s):  
H. Yamamoto ◽  
A. Kawamura ◽  
K. Tachihara ◽  
N. Mizuno ◽  
T. Onishi ◽  
...  
Keyword(s):  
Molecular Clouds ◽  
Large Scale ◽  
Far Infrared ◽  
Co Observations

scholarly journals CO Observations of Bright IRAS Galaxies

1987 ◽  
Vol 115 ◽  
pp. 653-653
Author(s):  
D. B. Sanders
Keyword(s):  
Star Formation ◽  
Molecular Clouds ◽  
Formation Rate ◽  
Far Infrared ◽  
Molecular Gas ◽  
Infrared Excess ◽  
Luminous Galaxies ◽  
Be Star ◽  
Co Emission ◽  
Co Observations

CO emission has been detected from 75 bright infrared galaxies with CZ = 2 000 – 16 000 km/s. These include the most distant and the most luminous galaxies (Arp 55, IR 1713+63) yet detected in CO. All of these galaxies are rich in molecular gas with Mtotal (H2) = 2 × 109 −6x1010 M⊙, and they have a strong far-infrared excess, with LFIR/LB = 2-40 and LFIR (40-400μ) = 1010 – 3 × 1012 L⊙. The primary luminosity source appears to be star formation in molecular clouds. A strong correlation is found between the FIR and 21-cm continuum flux, implying that the IMF is independent of the star formation rate. The ratio LFIR/M(H2) provides a measure of the current rate of star-formation, which is found to be a factor 3-20 larger in these galaxies than for the ensemble of molecular clouds in the Milky Way. VLA maps plus a few high resolution (14″-30″) CO (1-0) and CO (2-1) maps suggest that most of the luminosity comes from core regions 1-3 kpc in size. The abnormal concentration of molecular gas in these galactic cores is presumably the result of a collision or strong interaction with a nearby companion.

scholarly journals 4.5. Sub-mm [C I] and CO observations of molecular clouds presumably interacting by the G359.54+0.18 nonthermal filaments

1998 ◽  
Vol 184 ◽  
pp. 175-176
Author(s):  
J. Staguhn ◽  
J. Stutzki ◽  
S. P. Balm ◽  
A. A. Stark ◽  
A. P. Lane
Keyword(s):  
Molecular Clouds ◽  
Line Emission ◽  
Recombination Line ◽  
Molecular Line ◽  
Line Intensities ◽  
Angular Extent ◽  
H Ii Region ◽  
Morphological Differences ◽  
5 Ghz ◽  
Co Observations

We have investigated the physical properties of molecular clouds which are presumably interacting with the G359.54+0.18 Nonthermal Filaments and an associated H ii region east of the filaments (Staguhn et al., 1996). The sub-mm spectra of 12CO(3-2) were observed with the KOSMA 3 m telescope, while the 490 GHz [C i] 3P1 →3P0 observations were made with the AST/RO 1.7 m sub-mm telescope. Fig. 1 shows channel maps of the integrated CO and [C i] line intensities in the velocity range of the recombination line observed towards the nearby H ii region. This H ii region is traced by the VLA 5 GHz continuum observations which are shown as contours in the central parts of the maps. The G359.54+0.18 Nonthermal Filaments, situated further to the west, appear to be morphologically associated with the H ii region. The [C i] emission of the molecular cloud east of the filaments which is kinematically linked to the H ii region is anti-correlated with the molecular line emission over a large angular extent. It is unlikely that the large morphological differences between [C i] and CO in this region can be explained exclusively by a high abundance of neutral carbon in the surface regions of dense molecular clumps, as is usually the case in PDR regions near the Sun.

scholarly journals Protostellar Candidates in W75N

1987 ◽  
Vol 115 ◽  
pp. 187-187
Author(s):  
C. M. Mountain ◽  
I. Gatley ◽  
T. W. Hartquist ◽  
S. K. Leggett ◽  
M. J. Selby
Keyword(s):  
Molecular Hydrogen ◽  
Molecular Clouds ◽  
Large Scale ◽  
Far Infrared ◽  
Point Sources ◽  
Reflection Nebula ◽  
Infrared Sources

W75N is a highly obscured region containing far-infrared sources, masers and molecular clouds. New results are presented showing highly reddened point sources near the maser source W75N(OH). One of these sources appears to be illuminating a newly discovered reflection nebula exhibiting large scale fluorescent molecular hydrogen.

scholarly journals Mapping large-scale-structure evolution over cosmic times

2021 ◽  
Author(s):  
Marta B. Silva ◽  
Ely D. Kovetz ◽  
Garrett K. Keating ◽  
Azadeh Moradinezhad Dizgah ◽  
Matthieu Bethermin ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Large Scale ◽  
High Redshift ◽  
Formation Rate ◽  
Far Infrared ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Structure Evolution ◽  
Intensity Mapping ◽  
Wide Range

AbstractThis paper outlines the science case for line-intensity mapping with a space-borne instrument targeting the sub-millimeter (microwaves) to the far-infrared (FIR) wavelength range. Our goal is to observe and characterize the large-scale structure in the Universe from present times to the high redshift Epoch of Reionization. This is essential to constrain the cosmology of our Universe and form a better understanding of various mechanisms that drive galaxy formation and evolution. The proposed frequency range would make it possible to probe important metal cooling lines such as [CII] up to very high redshift as well as a large number of rotational lines of the CO molecule. These can be used to trace molecular gas and dust evolution and constrain the buildup in both the cosmic star formation rate density and the cosmic infrared background (CIB). Moreover, surveys at the highest frequencies will detect FIR lines which are used as diagnostics of galaxies and AGN. Tomography of these lines over a wide redshift range will enable invaluable measurements of the cosmic expansion history at epochs inaccessible to other methods, competitive constraints on the parameters of the standard model of cosmology, and numerous tests of dark matter, dark energy, modified gravity and inflation. To reach these goals, large-scale structure must be mapped over a wide range in frequency to trace its time evolution and the surveyed area needs to be very large to beat cosmic variance. Only a space-borne mission can properly meet these requirements.

scholarly journals CO observations of the 30-Doradus region using SEST

1991 ◽  
Vol 148 ◽  
pp. 157-159
Author(s):  
R. S. Booth ◽  
L.E.B. Johansson
Keyword(s):  
Molecular Clouds ◽  
Small Areas ◽  
The Relationship ◽  
Co Observations ◽  
30 Doradus

Using the Swedish-ESO Submillimetre Telescope, we have mapped the CO (1-0) emission in two small areas of the LMC near 30 Dor. Some 20 molecular clouds have been identified and analysed. Cloud masses are calculated assuming virial equilibrium and the relationship between mass and CO luminosity is discussed.

scholarly journals Discovery of the Carina Flare with NANTEN; Evidence for a Supershell That Triggered the Formation of Stars and Massive Molecular Clouds

1999 ◽  
Vol 51 (6) ◽  
pp. 751-764 ◽  
Author(s):  
Yasuo Fukui ◽  
Toshikazu Onishi ◽  
Rihei Abe ◽  
Akiko Kawamura ◽  
Kengo Tachihara ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Molecular Clouds ◽  
Galactic Plane ◽  
Far Infrared ◽  
Infrared Emission ◽  
High Mass ◽  
Stellar Winds ◽  
Neutral Gas ◽  
Supernova Explosions ◽  
Current Kinetic

Abstract We present extensive observations of the Carina arm region in the 2.6 mm CO (J = 1−0) emission with the NANTEN telescope in Chile. The observations have revealed 120 molecular clouds which are distributed in an area of 283° < l < 293° and 2° .5 < b < 10°. Because of its vertical elongation to the galactic plane, the clouds are named the Carina flare. H I and far-infrared emission show a cavity-like distribution corresponding to the molecular clouds, and soft X-ray emission appears to fill this cavity. It is shown that the Carina flare represents a supershell at a distance of a few kpc that has been produced by about 20 supernova explosions, or equivalent stellar winds of OB stars, over the last ∼ 2×107 yr. The supershell consisting of molecular and atomic neutral gas involves a total mass and kinetic energy of ≳ 3×105M⊙ and ≳ 3×1050 erg, respectively, and the originally injected energy required is about 100-times this current kinetic energy in the shell. It is unique among supershells known previously because of the following aspects: i) it exhibits evidence for the triggered formation of intermediate-to-high-mass stars and massive molecular clouds of 102 − 104M⊙, and ii) the massive molecular clouds formed are located unusually far above the galactic plane at z ∼ 100–500 pc.

scholarly journals CO and the Multiphase ISM

1997 ◽  
Vol 170 ◽  
pp. 25-32
Author(s):  
Christopher F. Mckee
Keyword(s):  
Mach Number ◽  
Magnetic Fields ◽  
Interstellar Medium ◽  
Molecular Clouds ◽  
Molecular Gas ◽  
Wave Pressure ◽  
Multiphase Structure ◽  
Co Observations

CO observations indicate that molecular clouds have a complex multiphase structure, and this is compared with the multiphase structure of the diffuse interstellar medium. The trace ionization within the molecular gas is governed primarily by UV photoionization. Magnetic fields contribute a significantly larger fraction of the pressure in molecular clouds than in the diffuse interstellar medium. Observations suggest that the total Alfvén Mach number, mAtot, of the turbulence in the diffuse ISM exceeds unity; Zeeman observations are consistent with mAtot ≲ 1 in molecular clouds, but more data are needed to verify this. Most molecular clouds are self-gravitating, and they can be modeled as multi-pressure polytropes with thermal, magnetic, and wave pressure. The pressure and density within self-gravitating clouds is regulated by the pressure in the surrounding diffuse ISM.

scholarly journals The atomic hydrogen/molecular cloud association: an unavoidable relationship

1991 ◽  
Vol 147 ◽  
pp. 37-40
Author(s):  
G. Joncas
Keyword(s):  
Atomic Hydrogen ◽  
Molecular Clouds ◽  
Large Scale ◽  
Young Stars ◽  
Physical Processes ◽  
Star Forming ◽  
Dark Clouds ◽  
Star Forming Regions ◽  
The Impact

The presence of HI in the interstellar medium is ubiquitous. HI is the principal actor in the majority of the physical processes at work in our Galaxy. Restricting ourselves to the topics of this symposium, atomic hydrogen is involved with the formation of molecular clouds and is one of the byproducts of their destruction by young stars. HI has different roles during a molecular cloud's life. I will discuss here a case of coexisting HI and H2 at large scale and the origin of HI in star forming regions. For completeness' sake, it should be mentionned that there are at least three other aspects of HI involvement: HI envelopes around molecular clouds, the impact of SNRs (see work on IC 443), and the role of HI in quiescent dark clouds (see van der Werf's work).

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