The Chandra Fornax Survey - I: The Cluster Environment

We present the first results of a deep Chandra survey of the inner 1 degree of the Fornax cluster of galaxies. Ten 50 ksec pointings were obtained in a mosaic centered on the giant elliptical galaxy NGC 1399 at the nominal cluster center. Emission and temperature maps of Fornax are presented, and an initial study of 771 detected X-ray point sources is made. Regions as small as 100pc are resolved. The intra-cluster gas in Fornax exhibits a highly asymmetric morphology and temperature structure, dominated by a 180 kpc extended ``plume'' of low surface brightness, cool, ~1 keV) gas to the North-East of NGC 1399 with a sharper edge to the South West. The elliptical galaxy NGC 1404 also exhibits a cool halo of X-ray gas within the cluster, with a highly sharpened leading edge as it presumably falls into the cluster, and a cometary-like tail. We estimate that some ~200-400 point sources are physically associated with Fornax. Confirming earlier works, we find that the globular cluster population in NGC 1399 is highly X-ray active, extending to globulars which may in fact be intra-cluster systems. We have also found a remarkable correlation between the location of giant and dwarf cluster galaxies and the presence of X-ray counterparts, such that systems inhabiting regions of low gas density are more likely to show X-ray activity. Not only does this correlate with the asymmetry of the intra-cluster gas but also with the axis joining the center of Fornax to an infalling group 1 Mpc to the South-West. We suggest that Fornax may be experiencing an intergalactic ``headwind'' due to motion relative to the surrounding large-scale structure.Comment: 35 pages, 15 figures, submitted to ApJ. Most figures not included owing to severe compression degradation - we strongly recommend downloading the full resolution paper from http://www.astro.columbia.edu/~caleb/ms_highres.pdf (1.9Mb

Clustering files of chemical structures using the Szekely-Rizzo generalization of Ward's method

Ward's method is extensively used for clustering chemical structures represented by 2D fingerprints. This paper compares Ward clusterings of 14 datasets (containing between 278 and 4332 molecules) with those obtained using the Szekely–Rizzo clustering method, a generalization of Ward's method. The clusters resulting from these two methods were evaluated by the extent to which the various classifications were able to group active molecules together, using a novel criterion of clustering effectiveness. Analysis of a total of 1400 classifications (Ward and Székely–Rizzo clustering methods, 14 different datasets, 5 different fingerprints and 10 different distance coefficients) demonstrated the general superiority of the Székely–Rizzo method. The distance coefficient first described by Soergel performed extremely well in these experiments, and this was also the case when it was used in simulated virtual screening experiments

A SAURON look at galaxy bulges

Kinematic and population studies show that bulges are generally rotationally flattened systems similar to low-luminosity ellipticals. However, observations with state-of-the-art integral field spectrographs, such as SAURON, indicate that the situation is much more complex, and allow us to investigate phenomena such as triaxiality, kinematic decoupling and population substructure, and to study their connection to current formation and evolution scenarios for bulges of early-type galaxies. We present the examples of two S0 bulges from galaxies in our sample of nearby galaxies: one that shows all the properties expected from classical bulges (NGC5866), and another case that presents kinematic features appropriate for barred disk galaxies (NGC7332).Comment: 4 pages, 3 figures, accepted for publishing in AN (refereed conf. proc. of the Euro3D Science workshop, IoA Cambridge, May 2003

Size matters: the value of small populations for wintering waterbirds

Protecting systematically selected areas of land is a major step towards biodiversity conservation worldwide. Indeed, the identification and designation of protected areas more often than not forms a core component of both national and international conservation policies. In this paper we provide an overview of those Special Protection Areas and Ramsar Sites that have been classified in Great Britain as of 1998/99 for a selection of wintering waterbird species, using bird count data from the Wetland Bird Survey. The performance of this network of sites is remarkable, particularly in comparison with published analyses of networks elsewhere in the world. Nevertheless, the current site-based approach, whilst having the great benefit of simplicity, is deliberately biased towards aggregating species at the expense of the more dispersed distribution species. To ensure that the network continues successfully to protect nationally and internationally important waterbird populations, efforts now need to concentrate on the derivation of species-specific representation targets and, in particular, the ways in which these can be incorporated into the site selection process. Although these analyses concern the performance of protected areas for waterbirds in Great Britain, the results have wide-ranging importance for conservation planning in general and the design of protected area networks

SAURON Observations of Disks in Spheroids

The panoramic integral-field spectrograph SAURON is currently being used to map the stellar kinematics, gaseous kinematics, and stellar populations of a large number of early-type galaxies and bulges. Here, we describe SAURON observations of cold stellar disks embedded in spheroids (NGC3384, NGC4459, NGC4526), we illustrate the kinematics and ionization state of large-scale gaseous disks (NGC4278, NGC7742), and we show preliminary comparisons of SAURON data with barred galaxy N-body simulations (NGC3623).Comment: 8 pages including 5 figures. To appear in Galaxies: The Third Dimension, eds. M. Rosado, L. Binnette, & L. Arias (ASP: San Francisco

SAURON: An Innovative Look at Early-Type Galaxies

A summary of the SAURON project and its current status is presented. SAURON is a panoramic integral-field spectrograph designed to study the stellar kinematics, gaseous kinematics, and stellar populations of spheroids. Here, the sample of galaxies and its properties are described. The instrument is detailed and its capabilities illustrated through observational examples. These includes results on the structure of central stellar disks, the kinematics and ionization state of gaseous disks, and the stellar populations of galaxies with decoupled cores.Comment: 10 pages, 6 figures. To appear in "The Dynamics, Structure & History of Galaxies", eds. G. S. Da Costa & E. M. Sadler (San Francisco: ASP). Version with full resolution images available at http://www.strw.leidenuniv.nl/~dynamics/Instruments/Sauron/pub_list.htm

LaVerkin Springs, Utah On-Site Pretreatment and Desalting Processes Evaluations

During December 1979 through August 1980, pilot plants and laboratory facilities were operated at the LaVerkin Springs, Utah site to characterize the water and to evaluate various pretreatment processes and desalting processes. The pretreatment processes studied included aeration-precipitation, lime treatment, lime-soda ash treatment, and lime-ion exchange treatment. Desalting at 80 and 90 percent water recovery levels was studied with both electrodialysis and high pressure reverse osmosis process equipment. Also, a spiractor was evaluated at the site as a lime-soda ash reactor and as a calcium sulfate desupersaturator. Data and results obtained from the test program will be used for feasibility study, cost estimates, and development and design of any future water collection system and pretreatment and desalting plant installations at the LaVerkin Springs site

Getting to where you want to go: 2022 Commencement address

Last academic year, Ouachita was one of the few universities to provide a fully in-person education. As we prepared for this year, we challenged ourselves to provide all the benefits of a traditional campus experience.In this effort to provide the typical in the least typical of times, we called on our seniors—the only class who remembered a year without COVID—to restore and revive the traditions that make Ouachita, Ouachita. You, our seniors, rose to the occasion, and I will forever be grateful for you, for the leadership you demonstrated and the example you set