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The redshifted 1420 MHz emission from the HI in unresolved damped Lyman-\alpha clouds at high z will appear as a background radiation in low frequency radio observations. This holds the possibility of a new tool for studying the universe at…

Astrophysics · Physics 2009-10-31 Somnath Bharadwaj , Biman B. Nath , Shiv K. Sethi

We investigate the density structure of the interstellar medium using new high-resolution maps of the 8 micron, 24 micron, and 70 micron surface brightness towards a molecular cloud in the Gum Nebula, made as part of the Spitzer Space…

Studies of dust scattering properties in astrophysical objects with Milky Way interstellar dust are reviewed. Such objects are reflection nebulae, dark clouds, and the Diffuse Galactic Light (DGL). To ensure their basic quality, studies had…

Astrophysics · Physics 2007-05-23 Karl D. Gordon

We present results of a method for an automatic search for HI shells in 3D data cubes and apply it to the Leiden-Dwingeloo HI survey of the northern Milky Way. In the 2nd Galactic quadrant, where identifications of structures are not…

Astrophysics · Physics 2013-01-18 S. Ehlerova , J. Palous

We present a power spectrum analysis of the Herschel-SPIRE observations of the Polaris flare, a high Galactic latitude cirrus cloud midway between the diffuse and molecular phases. The SPIRE images of the Polaris flare reveal for the first…

Neutral hydrogen traces gravitational potentials. In the nearby universe, 21cm emission-line surveys show that the bulk of the HI resides in well-formed, optically-luminous galaxies. At high redshift, 21cm line absorption against background…

Astrophysics · Physics 2007-05-23 F. H. Briggs

The optical surface brightness of dark nebulae is mainly due to scattering of integrated starlight by classical dust grains. It contains information on the impinging interstellar radiation field, cloud structure, and grain scattering…

Astrophysics of Galaxies · Physics 2016-12-21 K. Lehtinen , K. Mattila

This paper presents spectra in the 2 to 20 micron range of quiescent cloud material located in the IC 5146 cloud complex. The spectra were obtained with NASA's Infrared Telescope Facility (IRTF) SpeX instrument and the Spitzer Space…

Using a Fourier-plane technique, we have merged HI ATCA and Parkes data sets providing an accurate set of images of the LMC sensitive to structure on scales of 15 pc (for an LMC distance of 55 kpc) upwards. The spatial dynamic range (2.8…

Astrophysics · Physics 2008-11-26 S. Kim , L. Staveley-Smith , M. A. Dopita , R. J. Sault , K. C. Freeman , Y. Lee , Y. -H. Chu

In this study, we explore the impact of inhomogeneities in the spatial distribution of interstellar dust on spatial scales of $\le1$ au caused by ion shadowing forces on the optical properties of diffuse interstellar medium (ISM) as well as…

Astrophysics of Galaxies · Physics 2020-05-27 Andrei B. Ostrovskii , S. Yu. Parfenov , A. I. Vasyunin , A. V. Ivlev , V. A. Sokolova

We present preliminary results from the Southern Galactic Plane Survey (SGPS) Test Region and Parkes data. As part of the pilot project for the Southern Galactic Plane Survey, observations of a Test Region (325.5 deg < l < 333.5 deg; -0.5…

We present a detailed analytical and numerical analysis of the inelastic coherent backscattering spectrum of laser light incident on cold atoms. We identify frequency domains where the interference contribution can be positive \emph{as well…

Quantum Physics · Physics 2009-11-13 Vyacheslav Shatokhin , Thomas Wellens , Benoît Grémaud , Andreas Buchleitner

The structure of stationary photodissociation fronts is revisited. H_2 self- shielding is discussed, including the effects of line overlap. We find that line overlap is important for N(H_2) > 10^{20} cm^{-2}. We compute multiline UV pumping…

Astrophysics · Physics 2008-11-26 B. T. Draine , Frank Bertoldi

By radiation transfer models with a realistic power spectra of the projected density distributions, we show that the optical properties of grains are poorly constrained by observations of reflection nebulae. The ISM is known to be…

Astrophysics · Physics 2009-11-07 John S. Mathis , Barbara A. Whitney , Kenneth Wood

We investigate the physical structure and dust reprocessing in the shocks along the beam of a number of classical Herbig-Haro jets in the Orion and Lupus molecular cloud. Spectral diagnostic techniques are applied to obtain the jet physical…

Solar and Stellar Astrophysics · Physics 2015-05-13 L. Podio , S. Medves , F. Bacciotti , J. Eislöffel , T. P. Ray

A population of discrete HI clouds in the halo of the inner Galaxy has been discovered in 21cm observations made with the Green Bank Telescope. The halo clouds are seen up to 1.5 kpc from the Galactic plane at many longitudes. Their…

Astrophysics · Physics 2009-11-07 Felix J. Lockman

The distribution of dust in the ecliptic plane between 0.96 and 1.04 AU has been inferred from impacts on the two STEREO spacecraft through observation of secondary particle trails and unexpected off-points in the Heliospheric Imager (HI)…

Two continuum subtracted H-alpha HST frames of M101 are used to determine the positions, angular sizes and absolute fluxes of 237 HII regions using a semi-automated technique. From these we have constructed the luminosity and diameter…

Astrophysics · Physics 2016-08-30 P. O. Pleuss , C. H. Heller , K. J. Fricke

We report the radio detection of a shell-like HI structure in proximity to, and probably associated with, the nova V458 Vul. High spectral resolution observation with the Giant Metrewave Radio Telescope has made it possible to study the…

Astrophysics of Galaxies · Physics 2013-02-20 Nirupam Roy , N. G. Kantharia , S. P. S. Eyres , G. C. Anupama , M. F. Bode , T. P. Prabhu , T. J. O'Brien

We perform a statistical study of the turbulent power spectrum at inertial and kinetic scales observed during the first perihelion encounter of Parker Solar Probe. We find that often there is an extremely steep scaling range of the power…