T Pyx is a recurrent nova which has undergone eruptions on an almost
regular basis every 20 years until reaching a long lasting quiescence
between 1967 and 2011. We observed the long awaited 2011 explosion in
the optical and near infrared with intermediate spectral resolution. In
this paper we report on the change in the spectral type of the nova
(both during its rise and during its fading), as well as the observed
changes in the expansion velocities. We also present an interpretation
of these changes and set them in the general framework of a new
understanding of nova classification.
Luminosity functions are one of the most important observational clues
when studying galaxy evolution over cosmic time. In this paper we
present the X-ray luminosity functions for X-ray detected AGN in the SXDS and GWS fields. The limiting fluxes of our samples are 9.0
×10<SUP>-15</SUP> and 4.8 ×10<SUP>-16</SUP> erg
cm<SUP>-2</SUP> s<SUP>-1</SUP> in the 0.5-7.0 keV band in the two
fields, respectively. We carried out analysis in three X-ray bands and
in two redshift intervals up to z&leq;1.4. Moreover, we derive the
luminosity functions…
A 13 anni quasi perfettamente compiuti dalla Legge Regionale Lazio n. 23 del 13 aprile 2000 contro l'inquinamento luminoso e per l'uso razionale dell'energia, l'inquinamento luminoso provocato dalle luci artificiali della Capitale é ben lungi dall'essere limitato o controllato.
Questo primo decennio del Terzo Millennio é trascorso – sotto questo punto di vista – pressocché inutilmente.
13 anni di impegni e denunce non son bastati a dare effettiva attuazione della norma per cui tanto ci si era battuti sulla fine del millennio.
Soltanto nel 2005 si é riusciti a "strappare", non senza…
