ar X iv : a st ro - p h / 04 12 10 0 v 1 3 D ec 2 00 4 Variations of the Mid - IR Emission Spectrum in Reflection Nebulae

ar X iv : a st ro - p h / 04 12 37 4 v 1 1 5 D ec 2 00 4 Infrared emission in radio galaxy NGC 4261

We have analyzed the total and nuclear SED for NGC 4261 and find that the dominant process for the mid-and far-infrared emission in this object is non-thermal emission from the active nucleus. Modeling the emission from the optically detected 300 pc dust disk yields no significant disk contribution at any wavelength. To explain the observations, either the disk has an inflated inner region whic...

ar X iv : a st ro - p h / 06 12 37 8 v 1 1 4 D ec 2 00 6 Magnetic fields , strings and cosmology

ar X iv : a st ro - p h / 04 10 49 0 v 1 2 0 O ct 2 00 4 Radiation Processes in GRBs . Prompt Emission Mikhail

A substantial fraction of prompt GRB spectra have soft spectral indexes exceeding the maximum allowed by the synchrotron model αmax = −2/3. Some spectra also exhibit very sharp break at Ep, inconsistent with the smooth synchrotron spectra. These facts pose a serious problem for the “optically thin synchrotron” interpretation of the prompt emission. We review various models suggested in order to...

ar X iv : a st ro - p h / 06 12 53 0 v 1 1 9 D ec 2 00 6 High sensitivity low frequency radio observations of cD galaxies

We present the GMRT 235 MHz images of three radio galaxies and 610 MHz images of two sources belonging to a complete sample of cD galaxies in rich and poor galaxy clusters. The analysis of the spectral properties confirms the presence of aged radio emission in two of the presented sources.

ar X iv : a st ro - p h / 02 12 56 6 v 1 3 0 D ec 2 00 2 Dark Energy : Is it Q or Λ ?

New observations of Cosmic Microwave Background Anisotropies, Su-pernovae luminosity distances and Galaxy Clustering are sharpening our knowledge about dark energy. Here we present the latest constraints.