In the ancient world, terracotta sculpture was ubiquitous. Readily available and economical-unlike stone suitable for carving-clay allowed artisans to craft figures of remarkable variety and ...expressiveness. Terracottas from South Italy and Sicily attest to the prolific coroplastic workshops that supplied sacred and decorative images for sanctuaries, settlements, and cemeteries. Sixty terracottas are investigated here by noted scholar Maria Lucia Ferruzza, comprising a selection of significant types from the Getty's larger collection-life-size sculptures, statuettes, heads and busts, altars, and decorative appliqués. In addition to the comprehensive catalogue entries, the publication includes a guide to the full collection of over one thousand other figurines and molds from the region by Getty curator of antiquities Claire L. Lyons. The free online edition of this open-access catalogue, available at www.getty.edu/publications/terracottas/ includes zoomable high-resolution photography and a select number of 360° rotations; the ability to filter the catalogue by location, typology, and date; and an interactive map drawn from the Ancient World Mapping Center and linked to the Getty's Thesaurus of Geographic Names and Pleiades. Also available are free PDF, EPUB, and Kindle/MOBI downloads of the book; CSV and JSON downloads of the object data from the catalogue and the accompanying Guide to the Collection; and JPG and PPT downloads of the main catalogue images.
This first complete published catalogue of one of the most important classical sculpture collections in the United States includes 154 works from Italy, Greece, Cyprus, Asia Minor, North Africa, ...Roman Syria and Palestine, Egypt, and Babylonia, ranging in date from the late seventh century B.C. to the fourth century A.D.
Each piece receives a complete description with measurements and report of condition, a list of the previous published sources, and a commentary reflecting the most recent scholarship, along with extensive photographic documentation. Various audiences will appreciate the accessibility of the scholarship presented here-students may engage in further study on some of topics raised by individual pieces or groups of sculptures, and the scholarly community will welcome a work that provides an up-to-date and comprehensive examination of a significant classical sculpture collection in one of the world's great archaeology museums.
In light of substantial new discoveries of hot subdwarfs by ongoing spectroscopic surveys and the availability of new all-sky data from ground-based photometric surveys and the
Gaia
mission Data ...Release 2, we compiled an updated catalogue of the known hot subdwarf stars. The catalogue contains 5874 unique sources including 528 previously unknown hot subdwarfs and provides multi-band photometry, astrometry from
Gaia
, and classifications based on spectroscopy and colours. This new catalogue provides atmospheric parameters of 2187 stars and radial velocities of 2790 stars from the literature. Using colour, absolute magnitude, and reduced proper motion criteria, we identified 268 previously misclassified objects, most of which are less luminous white dwarfs or more luminous blue horizontal branch and main-sequence stars.
Cambridge University Library's collection of illuminated manuscripts is of international significance. It originates in the medieval university and stands alongside the holdings of the colleges and ...the Fitzwilliam Museum. The University Library contains major European examples of medieval illumination from the ninth to the sixteenth centuries, with acknowledged masterpieces of Romanesque, Gothic and Renaissance book art, as well as illuminated literary texts, including the first complete Chaucer manuscript. This catalogue provides scholars and researchers easy access to the University Library's illuminated manuscripts, evaluating the importance of many of them for the very first time. It contains descriptions of famous manuscripts, for example the Life of Edward the Confessor attributed to Matthew Paris, as well as hundreds of lesser-known items. Beautifully illustrated throughout, the catalogue contains descriptions of individual manuscripts with up-to-date assessments of their style, origins and importance, together with bibliographical references.
Gaia Data Release 2 Evans, D. W.; Riello, M.; De Angeli, F. ...
Astronomy and astrophysics (Berlin),
08/2018, Letnik:
616
Journal Article
Recenzirano
Odprti dostop
Aims.
We describe the photometric content of the second data release of the
Gaia
project (
Gaia
DR2) and its validation along with the quality of the data.
Methods.
The validation was mainly carried ...out using an internal analysis of the photometry. External comparisons were also made, but were limited by the precision and systematics that may be present in the external catalogues used.
Results.
In addition to the photometric quality assessment, we present the best estimates of the three photometric passbands. Various colour-colour transformations are also derived to enable the users to convert between the
Gaia
and commonly used passbands.
Conclusions.
The internal analysis of the data shows that the photometric calibrations can reach a precision as low as 2 mmag on individual CCD measurements. Other tests show that systematic effects are present in the data at the 10 mmag level.
Gaia Data Release 2 Luri, X.; Brown, A. G. A.; Sarro, L. M. ...
Astronomy and astrophysics (Berlin),
08/2018, Letnik:
616
Journal Article
Recenzirano
Odprti dostop
Context.
The second
Gaia
data release (
Gaia
DR2) provides precise five-parameter astrometric data (positions, proper motions, and parallaxes) for an unprecedented number of sources (more than 1.3 ...billion, mostly stars). This new wealth of data will enable the undertaking of statistical analysis of many astrophysical problems that were previously infeasible for lack of reliable astrometry, and in particular because of the lack of parallaxes. However, the use of this wealth of astrometric data comes with a specific challenge: how can the astrophysical parameters of interest be properly inferred from these data?
Aims.
The main focus of this paper, but not the only focus, is the issue of the estimation of distances from parallaxes, possibly combined with other information. We start with a critical review of the methods traditionally used to obtain distances from parallaxes and their shortcomings. Then we provide guidelines on how to use parallaxes more efficiently to estimate distances by using Bayesian methods. In particular we also show that negative parallaxes, or parallaxes with relatively large uncertainties still contain valuable information. Finally, we provide examples that show more generally how to use astrometric data for parameter estimation, including the combination of proper motions and parallaxes and the handling of covariances in the uncertainties.
Methods.
The paper contains examples based on simulated
Gaia
data to illustrate the problems and the solutions proposed. Furthermore, the developments and methods proposed in the paper are linked to a set of tutorials included in the
Gaia
archive documentation that provide practical examples and a good starting point for the application of the recommendations to actual problems. In all cases the source code for the analysis methods is provided.
Results.
Our main recommendation is to always treat the derivation of (astro-)physical parameters from astrometric data, in particular when parallaxes are involved, as an inference problem which should preferably be handled with a full Bayesian approach.
Conclusions.
Gaia
will provide fundamental data for many fields of astronomy. Further data releases will provide more data, and more precise data. Nevertheless, to fully use the potential it will always be necessary to pay careful attention to the statistical treatment of parallaxes and proper motions. The purpose of this paper is to help astronomers find the correct approach.
Context. The majority of stars form in clusters. Therefore a comprehensive view of star formation requires understanding the initial conditions for cluster formation. Aims. The goal of our study is ...to shed light on the physical properties of infrared dark clouds (IRDCs) and the role they play in the formation of stellar clusters. This article, the first of a series dedicated to the study of IRDCs, describes techniques developed to establish a complete catalogue of Spitzer IRDCs in the Galaxy. Methods. We have analysed Spitzer GLIMPSE and MIPSGAL data to identify a complete sample of IRDCs in the region of Galactic longitude and latitude 10° < |l|< 65° and |b| < 1°. From the 8 μm observations we have constructed opacity maps and used a newly developed extraction algorithm to identify structures above a column density of $N_{\rm{H_2}}$ $\ga$ 1 $\times$ 1022 cm-2. The 24 μm data are then used to characterize the star formation activity of each extracted cloud. Results. A total of 11 303 clouds have been extracted. A comparison with the existing MSX based catalogue of IRDCs shows that 80% of these Spitzer dark clouds were previously unknown. The algorithm also extracts ~20 000 to 50 000 fragments within these clouds, depending on detection threshold used. A first look at the MIPSGAL data indicates that between 20% and 68% of these IRDCs show 24 μm point-like association. This new database provides an important resource for future studies aiming to understand the initial conditions of star formation in the Galaxy.
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