Astrophysical point source search with the ANTARES neutrino telescope

The ANTARES neutrino telescope is installed at a depth of 2.5 km of the Mediterranean Sea and consists of a three-dimensional array of 885 photomultipliers arranged on twelve detector lines. The prime objective is to detect high-energy neutrinos from extraterrestrial origin. Relativistic muons emerging from charged-current muon neutrino interactions in the detector surroundings produce a cone of Cerenkov light which allows the reconstruction of the original neutrino direction. The collaboration has implemented different methods to search for neutrino point sources in the data collected since 2007. Results obtained with these methods as well as the sensitivity of the telescope are presented.Comment: 1 page, 1 figur

Freeform Surface Characterization and Instrument Alignment for Freeform Space Applications

CMM (Coordinate Measuring Machine) metrology provides simple, 3D (three dimensional) surface data used for prescription retrieval, figure error, and alignment with high accuracy without null-correctors. Two freeform mirrors for a compact telescope were successfully characterized and aligned using the CMM

Night sky brightness at sites from DMSP-OLS satellite measurements

We apply the sky brightness modelling technique introduced and developed by Roy Garstang to high-resolution DMSP-OLS satellite measurements of upward artificial light flux and to GTOPO30 digital elevation data in order to predict the brightness distribution of the night sky at a given site in the primary astronomical photometric bands for a range of atmospheric aerosol contents. This method, based on global data and accounting for elevation, Earth curvature and mountain screening, allows the evaluation of sky glow conditions over the entire sky for any site in the World, to evaluate its evolution, to disentangle the contribution of individual sources in the surrounding territory, and to identify main contributing sources. Sky brightness, naked eye stellar visibility and telescope limiting magnitude are produced as 3-dimensional arrays whose axes are the position on the sky and the atmospheric clarity. We compared our results to available measurements.Comment: 14 pages, 12 figures, accepted for publication in MNRAS, 17 june 200

A Magellan-IMACS-IFU Search for Dynamical Drivers of Nuclear Activity. I. Reduction Pipeline and Galaxy Catalog

Using the Inamori Magellan Areal Camera and Spectrograph (IMACS) integral-field unit (IFU) on the 6.5m Magellan telescope, we have designed the first statistically significant investigation of the two-dimensional distribution and kinematics of ionized gas and stars in the central kiloparsec regions of a well-matched sample of Seyfert and inactive control galaxies selected from the Sloan Digital Sky Survey. The goals of the project are to use the fine spatial sampling (0.2 arcsec/pixel) and large wavelength coverage (4000-7000A) of the IMACS-IFU to search for dynamical triggers of nuclear activity in the central region where active galactic nucleus (AGN) activity and dynamical timescales become comparable, to identify and assess the impact of AGN-driven outflows on the host galaxy and to provide a definitive sample of local galaxy kinematics for comparison with future three-dimensional kinematic studies of high-redshift systems. In this paper, we provide the first detailed description of the procedure to reduce and calibrate data from the IMACS-IFU in `long mode' to obtain two-dimensional maps of the distribution and kinematics of ionized gas and stars. The sample selection criteria are presented, observing strategy described and resulting maps of the sample galaxies presented along with a description of the observed properties of each galaxy and the overall observed properties of the sample.Comment: 62 pages. 41 figures. 5 tables. Accepted for publication in ApJS. High-resolution version available at: http://www.astro.ljmu.ac.uk/~pbw/IMACS-IFU/IMACS-1-highRes.pd

CWITools: A Python3 Data Analysis Pipeline for the Cosmic Web Imager Instruments

The Palomar Cosmic Web Imager (PCWI) and Keck Cosmic Web Imager (KCWI) are integral-field spectrographs on the Hale 5m telescope at Palomar Observatory and the Keck-2 10m telescope at W. M. Keck Observatory, respectively. In recent years, these instruments have been increasingly used to conduct survey work; in particular focused on the circumgalactic and intergalactic media at high redshift. Extracting faint signals from three-dimensional IFU data is a complex task which can become prohibitively difficult for large samples without the proper tools. We present CWITools, a package written in Python3 for the analysis of PCWI and KCWI data. CWITools is designed to provide a pipeline between the output of the standard instrument data reduction pipelines and scientific products such as surface brightness maps, spectra, velocity maps, as well as a wide array of associated models and measurements. While the package is designed specifically for PCWI and KCWI data, the package is open source and can be adapted to accommodate any three-dimensional integral field spectroscopy data. Here, we describe this pipeline, the methodology behind individual steps and provide example applications

Dimensional stability

The temporal stability of glass and glass-ceramic materials is important to the success of a large diffraction-limited telescope. The results are presented of an experimental study of the dimensional stability of glasses and glass ceramics being considered for substrates of massive diffraction-limited mirrors designed for several years of service in earth orbit. The purpose of the study was to measure the relative change in length of the candidate substrate materials, to the order of 5 parts in 10 to the 8th power, as a function of several years time. The development of monolithic test etalons, the development and improvement of two types of ultra-high precision interferometers, and certain aspects of tests data presently achieved are discussed

High-Dimensional Data Reduction, Image Inpainting and their Astronomical Applications

Technological advances are revolutionizing multispectral astrophysics as well as the detection and study of transient sources. This new era of multitemporal and multispectral data sets demands new ways of data representation, processing and management thus making data dimension reduction instrumental in efficient data organization, retrieval, analysis and information visualization. Other astrophysical applications of data dimension reduction which require new paradigms of data analysis include knowledge discovery, cluster analysis, feature extraction and object classification, de-correlating data elements, discovering meaningful patterns and finding essential representation of correlated variables that form a manifold (e.g. the manifold of galaxies), tagging astronomical images, multiscale analysis synchronized across all available wavelengths, denoising, etc. The second part of this paper is dedicated to a new, active area of image processing: image inpainting that consists of automated methods for filling in missing or damaged regions in images. Inpainting has multiple astronomical applications including restoring images corrupted by instrument artifacts, removing undesirable objects like bright stars and their halos, sky estimating, and pre-processing for the Fourier or wavelet transforms. Applications of high-dimensional data reduction and mitigation of instrument artifacts are demonstrated on images taken by the Spitzer Space Telescope