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Chemical evolution of the M82 B fossil starburst
de Grijs, Richard; Gilmore, Gerry; Parmentier, Geneviève
M82 B is an old starburst site located in the eastern part of the M82 disc. We derive the distributions of age and metallicity of the star clusters located in this region of M82 by using theoretical evolutionary population synthesis models. Our analysis is based on the comparison of the BVIJ photometry obtained by de Grijs, O'Connel & Gallaghe…
Scientific objectives of the Beagle 2 lander
Pillinger, C. T.; Sims, M. R.; Wright, I. P.
Beagle 2 is the name given to the lander part of the ESA Mars Express mission (launch 2003). The main focus of Beagle 2 is to establish whether there is convincing evidence for past life on Mars, or to assess if the conditions were ever suitable. Beagle 2 also plans a globally responsive test to see if there is any present-day biological activity …
Is Praesepe really different from the coeval Hyades cluster? The XMM-Newton view
Pallavicini, R.; Franciosini, E.; Randich, S.
The Praesepe open cluster represents a puzzle since it has about the same age as the Hyades, and only slightly different metallicity, yet previous ROSAT observations resulted in a detection rate of cluster sources significantly lower than for the Hyades. We present a new 50 ksec observation of Praesepe performed with the EPIC instrument on board X…
Massive Star Clusters in Ongoing Galaxy Interactions: Clues to Cluster Formation
Keel, William C.; Borne, Kirk D.
We present HST WFPC2 observations, supplemented by ground-based Hα data, of the star-cluster populations in two pairs of interacting galaxies selected for being in very different kinds of encounters seen at different stages. Dynamical information and n-body simulations provide the details of encounter geometry, mass ratio, and timing. In NGC 5752/…
Abundance Anomalies in CP Crucis (Nova Crux 1996)
Lumsden, S. L.; Krautter, Joachim; Gehrz, R. D. +15 more
We present spectroscopic observations of the classical nova CP Crucis (Nova Crux 1996) obtained with the Infrared Space Observatory Short Wavelength Spectrometer (ISO SWS) and the Anglo-Australian Telescope using both the Infrared Imaging Spectrograph and the Royal Greenwich Observatory Spectrograph. From the expansion parallax, we find that CP Cr…
The Origin of High-Energy 3He-rich Solar Particle Events
Torsti, J.; Kocharov, L.
Observed isotope abundances in the energy range >15 MeV nucleon-1 by the ERNE instrument on board Solar and Heliospheric Observatory show a group of high-energy 3He-rich solar particle events that apparently has not been identified in earlier observations. Those events are observed to start well after the flare, when the a…
The Dusty Environment of Quasars: Far-Infrared Properties of Optical Quasars
Grazian, Andrea; La Franca, Fabio; Cristiani, Stefano +2 more
We present Infrared Space Observatory (ISO) far-IR photometry of a complete subsample of optically selected bright quasars belonging to two complete surveys selected through multicolor (U, B, V, R, I) techniques. The ISOPHOT camera on board the ISO satellite was used to target these quasars at wavelengths of 7.3, 11.5, 60, 100, and 160 µm. A…
On the Extreme-Ultraviolet/Ultraviolet Plasma Diagnostics for Nitrogen-like Ions from Spectra Obtained By SOHO/SUMER
Dwivedi, B. N.; Mohan, A.; Landi, E.
In this work we discuss the potential for plasma diagnostics of forbidden transitions from the ground levels in the nitrogen-like ions: Al VII, Si VIII, P IX, S X, Ar XII, K XIII, and Ca XIV. We also study the lines emitted by n=3 levels of Si VIII. These transitions fall in the UV spectral range and have been recently observed by the SOHO/SUMER i…
Particle drift effects on cosmic ray modulation during solar maximum
Ferreira, S. E. S.; Potgieter, M. S.; Heber, B.
A fully time-dependent cosmic ray modulation model based on the numerical solution of Parker's transport equation is used to study the amount of particle drifts needed to explain the observed 1.2 GV electron to Helium ratio at Earth and the 2.5 GV electron to proton ratio (e/p) observed by the KET instrument on the Ulysses spacecraft. The model su…
Multiwavelength Spectroscopy of the Bipolar Outflow from Cepheus E
Smith, Michael D.; Eislöffel, Jochen; Froebrich, Dirk
Cepheus E is the site of an exceptional example of a protostellar outflow with a very young dynamical age and extremely high near-infrared luminosity. We combine molecular spectroscopic data from the submillimeter to the near-infrared in order to interpret the rotational excitation of CO and the rovibrational excitation of H2. We conclu…