Pubblicazioni

Sono presenti le pubblicazioni avvenute grazie al lavoro professionale o amatoriale dei soci ARA.

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FIR Measurements of Lyα Emitters at z <~ 1.0: Dust Attenuation from PACS-Herschel

Scritto il 14 Giu 2011 alle 01:35 in Pubblicazioni

One remaining open question regarding the physical properties of Lyα emitters (LAEs) is their dust content and evolution with redshift. The variety of results is large and with those reported by now it is difficult to establish clear relations between dust, other fundamental parameters of galaxies (star formation rate, metallicity, or age), and redshift. In this Letter, we report Herschel PACS-100 μm, PACS-160 μm, and Spitzer MIPS-24 μm detections of a sample of spectroscopically GALEX selected LAEs at z ~ 0.3 and ~ 1.0. Five out of ten and one out of two LAEs are detected in, at...

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Development of discrete velocity components in the optical spectrum of T Pyx

Scritto il 07 Giu 2011 alle 01:35 in Pubblicazioni

We have continued out high resolution optical spectroscopy of the latest
outburst of T Pyx with the FIES fiber-fed echelle (R ~ 67000) as first
reported in ATel 3306. Here we describe the changes in the optical
resonance and Fe II lines. The first observation, obtained on 2011 Apr.
15.92 UT, shows a pre-maximum spectrum (e.g. McLaughlin, D. B. 1964,
Ann.Ap., 27, 450, now identified as the so-called fireball stage)
showing only Balmer series and He I/II with P Cyg components extending
to -3000 km/s, and a complex blend at C III/ N II 4640 A.

Estimate of reddening for T Pyx based on optical diffuse interstellar bands (DIBs)

Scritto il 07 Giu 2011 alle 01:35 in Pubblicazioni

We report the first results for the latest outburst of the recurrent
nova T Pyx from the FIES echelle spectrograph on the 2.6 m Nordic
Optical Telescope (NOT) at La Palma from 3700-7200 A with a resolution
of 67000. The first spectrum, obtained on 2011 Apr. 15.92 UT during the
rise to maximum (V approx 9.5) with integration time of 600 sec with a
S/N of 30 at 6000 A (continuum), was sufficiently well exposed to
display some of the strongest optical diffuse interstellar bands (DIBs).

Ves 205: possibile controparte ottica di 1AGL J2022+4032?

Scritto il 28 Mag 2011 alle 10:38 in Pubblicazioni

La sorgente 1AGL J2022+4032 è la sorgente gamma persistente più intensa della regione del Cigno. Essa è associata alla più intensa sorgente non identificata del terzo catalogo di EGRET, e solo recentemente Fermi l’ha identificata come una pulsar gamma. La sorgente si trova all’interno dell’estensione angolare della SNR Gamma Cygni (G78.2+2.1). Basandosi sulle osservazioni prolungate del satellite AGILE in direzione del Cigno tra Novembre 2007 e Luglio 2009 (~11 Ms di tempo di esposizione netta), si è svolta un’analisi sulla variabilità in flusso della sorgente. Lo studio ha mostrato...

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The Day the Earth Trembled

Scritto il 28 Mag 2011 alle 10:36 in Pubblicazioni

When the sun began to rise on the morning of 13 August 1930 like any other morning, little did the inhabitants along the banks of the River Curuçá in the Brazilian Amazonas region, near the Peruvian frontier, realise what was about to happen. The women of the community had started washing clothing and the fishermen and rubber-tappers had begun their days work. Suddenly, at about eight o’clock, the sun became blood-red and a darkness fell over the region. A large cloud of red dust filled the air, and then a fine white ash descended to cover the trees and plants. There then followed...

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