Highly ionized gas has been detected at large distances from the nucleus in several classes of active galaxies. There is evidence that photoionization by the active nucleus may be the most relevant mechanism for the observed ionization. The spatial distribution of such gas has a conical shape, whose vertex points towards the nucleus and the axis is

Evolutionary synthesis models are a fundamental tool to interpret the properties of observed stellar systems. In order to achieve a meaningful comparison between models and real data, it is necessary to calibrate the models themselves, i.e. to evaluate the dispersion due to the discreteness of star formation as well as the possible model errors. In

We have confirmed the detection of a surprising, and so far unique, absorption feature on a main-belt asteroid, 24 Themis. Our 2 to 4 micron reflectance spectra were obtained over 7 hours (84% of Themis’ rotational period) on January 23, 2008 UT, from NASA's Infrared Telescope Facility. All our spectra confirm the shape and depth of the 3.1 micron

Constellation-X will obtain for the first time high quality X-ray spectra for all classes of X-ray sources, over a wide range of luminosity and distance. It is the second priority in the National Academy of Sciences Decadal survey in the major space based missions category (after JWST). Over the past few years, NASA budgets for SMD have been

Spontaneous breaking of Lorentz symmetry at energies on the order of the Planck energy or lower is predicted by many quantum gravity theories, implying non-trivial dispersion relations for the photon in vacuum. Consequently, gamma-rays of different energies, emitted simultaneously from astrophysical sources, could accumulate measurable differences

The CMB temperature-redshift relation, TCMB(z)=T0(1+z), is a key prediction of the standard cosmology but is violated in many non-standard models. Constraining possible deviations from this law is an effective way to test the ΛCDM paradigm and to search for hints of new physics. We have determined TCMB(z), with a precision up to 3%, for a subsample