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.
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).
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…
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…
We study the long-term, S Dor-type variability and the present hot phase of the luminous blue variable (LBV) star GR 290 (Romano’s Star) in M 33 in order to investigate possible links between the LBV and the late, nitrogen sequence Wolf–Rayet Stars (WNL) stages of very massive stars. We use intermediate-resolution spectra, obtained with the William Herschel Telescope (WHT) in 2008 December, when GR 290 was at minimum (V = ∼18.6), as well as new low-resolution spectra and BVRI photometry obtained with the Loiano and Cima Ekar telescopes during 2007–2010.
