Search results for "EIA"

The Contribution of Microchemical Analyses and Diagnostic Imaging to the Conservation and Identification of the Degraded Surfaces of Hellenistic-Roma…

2020

The Archaeological Museum of Palermo (Sicily) has recently presented the results of the restoration of three wall paintings from the House of the Masks of Solunto archaeological site. These significant paintings, dating back to the first century BCE, are the most significant examples of Pompeian style discovered in Sicily to date. The cycle of frescoes unearthed is the best preserved and most complete example of wall painting dating to the Republican Roman period in Sicily. This house was a luxurious private residence built on two floors and centred around a peristyle. This fresco cycle embellished the walls of a banquet room (oecus) discovered during an archaeological excavation carried ou…

Discurso del Dotor Thomas Cerdan de Tallada ... dirigido a la Magestad Catholica, en beneficio y notable aumento del patrimonio y Regalias que tanto …

1612

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Representación que en 10 de enero de 1861 han hecho al Congreso los centenares de vecinos y propietarios de Murviedro y de los pueblos que existen de…

Luminosity and Mass Function of the Galactic open cluster NGC 2422

2003

We present UBVRI photometry of the open cluster NGC 2422 (age $\sim 10^8$ yr) down to a limiting magnitude $V\simeq19$. These data are used to derive the Luminosity and Mass Functions and to study the cluster spatial distribution. By considering the color-magnitude diagram data and adopting a representative cluster main sequence, we obtained a list of candidate cluster members based on a photometric criterion. Using a reference field region and an iterative procedure, a correction for contaminating field stars has been derived in order to obtain the Luminosity and the Mass Functions in the $M=0.4-3.5 M_\odot$ range. By fitting the spatial distribution, we infer that a non-negligible number …

Optical and near-infrared recombination lines of oxygen ions from Cassiopeia A knots

2008

Context. Fast-moving knots (FMK) in the Galactic supernova remnant Cassiopeia A consist mainly of metals and allow to study element production in supernovae and shock physics in great detail. Aims. We work out theoretically and suggest to observe previously unexplored class of spectral lines -- metal recombination lines in optical and near-infrared bands -- emitted by the cold ionized and cooling plasma in the fast-moving knots. Methods. By tracing ion radiative and dielectronic recombination, collisional $l$-redistribution and radiative cascade processes, we compute resulting oxygen, silicon and sulphur recombination line emissivities. It allows us to determine the oxygen recombination lin…

Deep X-ray survey of the young open cluster NGC 2516 with XMM-Newton

2006

We report on a deep X-ray survey of the young (~ 140 Myr), rich open cluster NGC 2516 obtained with the EPIC camera on board the XMM-Newton satellite. By combining data from six observations, a high sensitivity, greater than a factor 5 with respect to recent Chandra observations, has been achieved. We detected 431 X-ray sources and 234 of them have as optical counterparts cluster stars spanning the entire NGC 2516 Main Sequence. The X-ray luminosities of cluster stars span the range log Lx (erg/s) = 28.4 - 30.8. The representative temperatures span the 0.3 - 0.6 keV (3.5 - 8 MK) range for the cool component and 1.0 - 2.0 keV (12 -- 23 MK) for the hot one; similar values are found in other y…

Fine-structure infrared lines from the Cassiopeia A knots

2008

Aims: Archival observations of infrared fine-structure lines of the young Galactic supernova remnant Cassiopeia A allow us to test existing models and determine the physical parameters of various regions of the fast-moving knots (FMKs), which are metal-dominated clouds of material ejected by the supernova explosion. Methods: The fluxes of the far-infrared [O i] and [O iii] lines are extracted from the previously unpublished archival ISO data. The archival Spitzer data are used to determine the fluxes of the O, Ne, Si, S, Ar and Fe ion fine-structure lines originating in the FMKs. The ratios of these line fluxes are used for the plasma diagnostics. We also determine the infrared line flux ra…

ROSAT PSPC/HRI observations of the open cluster NGC 2422

2002

We present the results of a ROSAT study of NGC 2422, a southern open cluster at a distance of about 470 pc, with an age close to the Pleiades. Source detection was performed on two observations, a 10-ks PSPC and a 40-ks HRI pointing, with a detection algorithm based on wavelet transforms, particularly suited to detecting faint sources in crowded fields. We have detected 78 sources, 13 of which were detected only with the HRI, and 37 detected only with the PSPC. For each source, we have computed the 0.2-2.0 keV X-ray flux. Using optical data from the literature and our own low-dispersion spectroscopic observations, we find candidate optical counterparts for 62 X-ray sources, with more than 8…

Dependence of coronal X-ray emission on spot-induced brightness variations in cool main sequence stars

2003

The maximum amplitude (A m a x ) of spot-induced brightness variations from long-term V-band photometry and the ratio L x /L ? o l between X-ray and bolometric luminosities are suitable indicators of the level of magnetic activity in the photosphere and in the corona of late-type stars, respectively. By using these activity indicators we investigate the dependence of coronal X-ray emission on the level of photospheric starspot activity in a homogeneous sample of low mass main sequence field and cluster stars of different ages (IC 2602, IC 4665, IC 2391, a Persei, Pleiades and Hyades). First, the activity-rotation connection at the photospheric level is re-analysed, as well as its dependence…

The X-ray luminosity of solar-mass stars in the intermediate age open cluster NGC 752

2008

AIMS. While observational evidence shows that most of the decline in a star's X-ray activity occurs between the age of the Hyades (~8 x 10^8 yrs) and that of the Sun, very little is known about the evolution of stellar activity between these ages. To gain information on the typical level of coronal activity at a star's intermediate age, we studied the X-ray emission from stars in the 1.9 Gyr old open cluster NGC 752. METHODS. We analysed a ~140 ks Chandra observation of NGC 752 and a ~50 ks XMM-Newton observation of the same cluster. We detected 262 X-ray sources in the Chandra data and 145 sources in the XMM-Newton observation. Around 90% of the catalogued cluster members within Chandra's …