Dust energetics in the gas phases of the interstellar medium - The origin of the Galactic large-scale far-infrared emission observed by IRAS

1989 ◽  
Vol 336 ◽  
pp. 762 ◽  
Author(s):  
T. J. Sodroski ◽  
E. Dwek ◽  
M. G. Hauser ◽  
F. J. Kerr
Keyword(s):  
Interstellar Medium ◽  
Large Scale ◽  
Far Infrared ◽  
Infrared Emission ◽  
Gas Phases

scholarly journals Star Formation in the NGC 2071 Molecular Cloud

1989 ◽  
Vol 120 ◽  
pp. 128-128
Author(s):  
N.J. Evans
Keyword(s):  
Star Formation ◽  
High Resolution ◽  
Density Distribution ◽  
Molecular Cloud ◽  
Large Scale ◽  
Far Infrared ◽  
Infrared Emission ◽  
Molecular Outflow ◽  
Broad Array ◽  
Coherent Picture

The NGC 2071 molecular cloud has been studied with a broad array of techniques, including a large scale study of CS emission, high resolution scans in the far-infrared, N H3 studies with the VLA, and near-infrarred imaging. The far-infrared emission constrains the density distribution to fall off approximately as r−1. The NH3 data strongly supports the presence of a disk oriented perpendicular to the molecular outflow, while the CS emission indicates the presence of dense gas in the region. The results will be combined into a coherent picture of this region of current star formation and molecular outflow.

scholarly journals Fractal Dust Grains

1989 ◽  
Vol 135 ◽  
pp. 337-342
Author(s):  
Edward L. Wright
Keyword(s):  
Interstellar Medium ◽  
Analytical Calculation ◽  
Far Infrared ◽  
Interplanetary Dust ◽  
Infrared Emission ◽  
Dipole Approximation ◽  
Extinction Curve ◽  
Dust Particles ◽  
Interplanetary Dust Particles ◽  
Emission Efficiency

Dust particles in the interstellar medium are almost certainly not spherical or any other shape which allows an analytical calculation of the extinction curve, even in the Rayleign limit. Particles in soot and interplanetary dust particles are aggregates formed by subclusters which stick together. This paper uses the discrete dipole approximation (DDA) to compute the absorption and extinction curves for fractal shapes generated by this clustering process. For fractals made from graphite the UV extinction curve shows a bump near the observed 220 nm feature, and a far infrared emission efficiency many times greater than that for spheres.

scholarly journals Spatial power spectra of dust across the Local Group: No constraint on disc scale height

2019 ◽  
Vol 492 (2) ◽  
pp. 2663-2682 ◽  
Author(s):  
Eric W Koch ◽  
I-Da Chiang (江宜達) ◽  
Dyas Utomo ◽  
Jérémy Chastenet ◽  
Adam K Leroy ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Power Law ◽  
Large Scale ◽  
Power Spectra ◽  
Far Infrared ◽  
Infrared Emission ◽  
Scale Height ◽  
Turbulent Motion ◽  
Spatial Power Spectrum ◽  
30 Doradus

ABSTRACT We analyse the 1D spatial power spectra of dust surface density and mid to far-infrared emission at $24\!-\!500\, \mu$m in the LMC, SMC, M31, and M33. By forward-modelling the point spread function (PSF) on the power spectrum, we find that nearly all power spectra have a single power-law and point source component. A broken power-law model is only favoured for the LMC 24 μm MIPS power spectrum and is due to intense dust heating in 30 Doradus. We also test for local power spectrum variations by splitting the LMC and SMC maps into 820 pc boxes. We find significant variations in the power-law index with no strong evidence for breaks. The lack of a ubiquitous break suggests that the spatial power spectrum does not constrain the disc scale height. This contradicts claims of a break where the turbulent motion changes from 3D to 2D. The power spectrum indices in the LMC, SMC, and M31 are similar (2.0–2.5). M33 has a flatter power spectrum (1.3), similar to more distant spiral galaxies with a centrally-concentrated H2 distribution. We compare the power spectra of H i, CO, and dust in M31 and M33, and find that H i power spectra are consistently flatter than CO power spectra. These results cast doubt on the idea that the spatial power spectrum traces large scale turbulent motion in nearby galaxies. Instead, we find that the spatial power spectrum is influenced by (1) the PSF on scales below ∼3 times the FWHM, (2) bright compact regions (30 Doradus), and (3) the global morphology of the tracer (an exponential CO disc).

scholarly journals Diagnosing the interstellar medium of galaxies with far-infrared emission lines. I. The [CII] 158 mum line at z~0

2020 ◽  
Author(s):  
A.F. Ramos Padilla ◽  
L. Wang ◽  
S. Ploeckinger ◽  
F. F. S. van der Tak ◽  
S. C. Trager
Keyword(s):  
Interstellar Medium ◽  
Far Infrared ◽  
Infrared Emission ◽  
Emission Lines

scholarly journals Polarized Infrared Emission from Dust

1989 ◽  
Vol 135 ◽  
pp. 275-281 ◽  
Author(s):  
Roger H. Hildebrand
Keyword(s):  
Magnetic Fields ◽  
Large Scale ◽  
Far Infrared ◽  
Infrared Emission ◽  
Degree Of Polarization ◽  
Dust Grains ◽  
Infrared Observations ◽  
Intercloud Medium

At the beginning of this decade what we knew about polarization of far-infrared emission from dense clouds was that some very good observers had looked for it and had not found it. Gull et al. (1978) had shown that the degree of polarization in Orion was not more than 2%. That information provided an important guide but very little encouragement for later efforts. There was reason to doubt whether the mechanisms invoked to explain the alignment of dust grains in the diffuse intercloud medium would operate in dense clouds; whether the strengths of the magnetic fields in dense clouds would be sufficiently greater than those in the intercloud medium to overcome the higher rate at which gas collisions would destroy alignment; and whether the field, if sufficient locally, would have enough large-scale order to give measurable polarization in far-infrared observations with large beams and large column depths.

scholarly journals Large-scale distributions of mid- and far-infrared emission from the center to the halo of M 82 revealed with AKARI

2010 ◽  
Vol 514 ◽  
pp. A14 ◽  
Author(s):  
H. Kaneda ◽  
D. Ishihara ◽  
T. Suzuki ◽  
N. Ikeda ◽  
T. Onaka ◽  
...  
Keyword(s):  
Large Scale ◽  
Far Infrared ◽  
Infrared Emission

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.

Far-Infrared Polarimetry of the Interstellar Medium

2011 ◽  
Vol 52 ◽  
pp. 259-262
Author(s):  
J.E. Vaillancourt ◽  
C.D. Dowell ◽  
T.J. Jones ◽  
G. Novak ◽  
D.T. Chuss ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Far Infrared

Far infrared emission from magnetically quantised 2DEGs in GaAs/(AlGa)As heterojunctions

1994 ◽  
Vol 305 (1-3) ◽  
pp. 280-284 ◽  
Author(s):  
N.N. Zinov'ev ◽  
R. Fletcher ◽  
L.J. Challis ◽  
B. Sujak-Cyrul ◽  
A.V. Akimov ◽  
...  
Keyword(s):  
Far Infrared ◽  
Infrared Emission
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