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An important contribution to the gamma-ray emission of our Galaxy is the Galactic Diffuse emission. We present specific developments within the PICARD code for modeling of Galactic cosmic ray propagation that are relevant for the computation of the gamma-ray emission to accommodate a new Interstellar Radiation Field (ISRF) model. We study the differences of the individual ISRF models on Galactic Diffuse gamma-ray emission predictions in the GeV to the TeV energy regime. Emphasis was laid on obtaining robust predictions for observable signatures in the very high energy gamma-ray regime with a special attention to the energy regime for H.E.S.S. Preliminary longitude-latitude profile and residuum maps of inverse Compton emissions are shown for axisymmetric and four-arm spiral Galaxy models. [ABSTRACT FROM AUTHOR]

Understanding the infrared emission of galaxies is critical to observational and theoretical investigations of the condensation of galaxies out of the intergalactic medium and the conversion of gas into stars over cosmic time. From an observational perspective, about half of all photons emitted within galaxies are locally absorbed by dust grains, necessitating a self-consistent analysis of the panchromatic emission of galaxies to quantify star-formation and AGN activity as a function of epoch and environment. From a theoretical perspective, physical processes involving dust are expected to play a major role in regulating the accumulation of baryons in galaxies and their condensation into stars on scales ranging from Mpc down to sub-pc. All this requires a quantitative analysis of the interaction between dust, gas and radiation. Here we review progress in the modelling of some of these processes. [ABSTRACT FROM AUTHOR]

It is now beyond doubt that dust in star-forming galaxies plays a crucial role both in shaping our perception of the universe as well as mediating the physical processes governing the heating and cooling of gas in these systems. Here we review our knowledge of dust in galaxies and show how we can quantitatively unveil the effects of dust in galaxies. [ABSTRACT FROM AUTHOR]

Dust physics is important both for observational and computational investigations of the processes governing the condensation of galaxies out of the intergalactic medium and the subsequent conversion of gas into stars within galaxies. Here we review these processes and outline future prospects for placing direct observational constraints on them using the upcoming generation of far-infrared and submillimeter observatories. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

We give an overview of the factors shaping the ultraviolet (UV)/optical — far-infrared (FIR)/submillimeter (submm) spectral energy distributions (SEDs) of normal (non-starburst) galaxies. Particular emphasis is placed on the influence of the geometry of dust and stars on the propagation of light through the interstellar medium. Although strong constraints can be placed on the amount and large scale distribution of dust in disks from the appearance of the galaxies in the optical/UV range, this dust does not account for the observed amplitude and colour of the FIR/submm radiation. Additional, optically thick components of dust associated with the young stellar population on large and small scales are required to account for the complete UV/optical — FIR/submm SEDs. Self-consistent models for the calculation of SEDs of spiral galaxies are reviewed, and their predictions for the dust emission and the attenuation of starlight are compared and contrasted. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Following on from IRAS, the ISOPHOT instrument on board the Infrared Space Observatory (ISO) has provided a huge advancement in our knowledge of the phenomenology of the far-infrared (FIR) emission of normal galaxies and the underlying physical processes. Highlights include: the discovery of an extended cold dust emission component, present in all types of gas-rich galaxies and carrying the bulk of the dust luminosity; the definitive characterisation of the spectral energy distribution in the FIR, revealing the channels through which stars power the FIR light; the derivation of realistic geometries for stars and dust from ISOPHOT imaging and the discovery of cold dust associated with HI extending beyond the optical body of galaxies. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

2MASS and Spitzer images of the edge-on galaxy NGC 7814 were used to extract the morphologies and spectral energy distributions (SEDs) of the disk, bulge and halo components of this galaxy from 1.25 to 24 μm. This represents the first direct determination of the mid-infrared emission of the bulge and halo components of a galaxy other than the Milky Way. The SEDs of all three structures imply the presence of emission components from direct stellar light and from at least one further component. For the disk, this is interpreted as dust emission having properties typical of star forming disks. The very significant excess emission from the bulge and the halo has an unknown origin. We discuss potential explanations such as dust emission in an interstellar medium, galactic winds, star forming regions and circumstellar dust, as well as emission from brown dwarfs. [ABSTRACT FROM AUTHOR]