2 research outputs found
GASPS observations of Herbig Ae/Be stars with PACS/Herschel. The atomic and molecular content of their protoplanetary discs
We observed a sample of 20 representative Herbig Ae/Be stars and five A-type
debris discs with PACS onboard of Herschel. The observations were done in
spectroscopic mode, and cover far-IR lines of [OI], [CII], CO, CH+, H2O and OH.
We have a [OI]63 micron detection rate of 100% for the Herbig Ae/Be and 0% for
the debris discs. [OI]145 micron is only detected in 25%, CO J=18-17 in 45%
(and less for higher J transitions) of the Herbig Ae/Be stars and for [CII] 157
micron, we often found spatially variable background contamination. We show the
first detection of water in a Herbig Ae disc, HD 163296, which has a settled
disc. Hydroxyl is detected as well in this disc. CH+, first seen in HD 100546,
is now detected for the second time in a Herbig Ae star, HD 97048. We report
fluxes for each line and use the observations as line diagnostics of the gas
properties. Furthermore, we look for correlations between the strength of the
emission lines and stellar or disc parameters, such as stellar luminosity, UV
and X-ray flux, accretion rate, PAH band strength, and flaring. We find that
the stellar UV flux is the dominant excitation mechanism of [OI]63 micron, with
the highest line fluxes found in those objects with a large amount of flaring
and greatest PAH strength. Neither the amount of accretion nor the X-ray
luminosity has an influence on the line strength. We find correlations between
the line flux of [OI]63 micron and [OI]145 micron, CO J = 18-17 and [OI]6300
\AA, and between the continuum flux at 63 micron and at 1.3 mm, while we find
weak correlations between the line flux of [OI]63 micron and the PAH
luminosity, the line flux of CO J = 3-2, the continuum flux at 63 micron, the
stellar effective temperature and the Brgamma luminosity. (Abbreviated version)Comment: 20 pages, 29 figures, accepted by Astronomy and Astrophysic
Tra politica e propaganda. Le relazioni dell'Italia fascista con l'Egitto (1922-1943)
Dall'ascesa al potere del fascismo, Mussolini dedicò una speciale attenzione al mondo arabo e all'Egitto in particolare.
Se nel corso degli anni Venti il Duce fu assorbito dalla stabilizzazione del regime e dalla ricerca del consenso nella politica europea, gli anni Trenta si inaugurarono con una volontà forte e determinata: affermare l'influenza economica, politica e culturale nel paese arabo. Questo avvenne sia attraverso i mezzi di propaganda, sia attraverso i contatti con i leader dei movimenti nazionalisti locali che si riferivano al fascismo. Lo scoppio della II guerra mondiale segnò il momento di massimo sforzo dell'azione fascista e per alcuni istanti si nutrì la speranza di creare un "Nuovo Ordine mediterraneo"