There is now ample evidence that the interstellar thick disks of spiral galaxies are dusty. Although the majority of extraplanar gas in the first few kiloparsecs above the plane of a spiral galaxy is matter that has been expelled from the thin disk, the feedback-driven expulsion does not destroy dust grains altogether (and there is not yet any good measure suggesting it changes the dust-to-gas ...

Introduction: Infrared observations indicate that a dominant fraction of the condensed matter found in the interstellar medium (ISM) is amorphous (silicates, organic matter, ices). On the other hand, similar spectroscopic studies show that silicates are mainly crystalline in protoplanetary disks [1]. Furthermore, cometary material appears also essentially crystalline [2, 3]. Because the ISM dus...

We report on a search for the parental molecular clouds of the TW Hya association (TWA), using CO emission and Na I absorption lines. TWA is the nearest young (∼ 50 pc; ∼ 10 Myr) stellar association, yet in spite of its youth, there are no detection of any associated natal molecular gas, as is the case for other typical young clusters. Using infrared maps as a guide, we conducted a CO cloud sur...

The morphology of the infrared (IR) emission and the properties of discrete farinfrared (FIR) sources in M31 disk are studied using the high resolution (HiRes) maps from IRAS. Very thin and bright FIR arm segments are shown in these maps, which have similar structure as the HI gas but with much enhanced arm/inter-arm contrast, typically a factor of 5 on the 60 m image. We identify 39 unconfused...

Molecular clouds constitute the densest parts of the interstellar medium in galaxies, and ever since their discovery 25 years ago they have been of prime interest as the sites of star formation. Molecular clouds also play an important galactic role in that massive stars recently formed in them provide the main energy sources for the interstellar medium, partly by destroying their birth clouds a...

High energy electrons and positrons from decaying dark matter can produce a significant flux of gamma rays by inverse Compton off low energy photons in the interstellar radiation field. This possibility is inevitably related with the dark matter interpretation of the observed PAMELA and FERMI excesses. The aim of this paper is providing a simple and universal method to constraint dark matter mo...

Accounting for the different contributions of aromatic rings, separated with sp 3 bonds, ab initio method we constructed hybrid cluster C 73 H 74 which UV spectrum matches most noticeable absorption band 217.5 nm, known from astrophysical observations Keywords: interaction light matter, new forms carbon, interstellar medium.

Aims. We describe the assignment of a previously unidentified interstellar absorption line to ArH and discuss its relevance in the context of hydride absorption in diffuse gas with a low H2 fraction. The confidence of the assignment to ArH is discussed, and the column densities are determined toward several lines of sight. The results are then discussed in the framework of chemical models, with...

We analyse IRAS and COBE DIRBE data at wavelengths between 2.2 and 240 µm of the central 500 pc of the Galaxy and derive the large-scale distribution of stars and interstellar matter in the Nuclear Bulge. Models of the Galactic Disk and Bulge are developed in order to correctly decompose the total surface brightness maps of the inner Galaxy and to apply proper extinction corrections. The Nuclea...