GPU Acceleration of Image Convolution using Spatially-varying Kernel

Image subtraction in astronomy is a tool for transient object discovery such as asteroids, extra-solar planets and supernovae. To match point spread functions (PSFs) between images of the same field taken at different times a convolution technique is used. Particularly suitable for large-scale images is a computationally intensive spatially-varying kernel. The underlying algorithm is inherently massively parallel due to unique kernel generation at every pixel location. The spatially-varying kernel cannot be efficiently computed through the Convolution Theorem, and thus does not lend itself to acceleration by Fast Fourier Transform (FFT). This work presents results of accelerated implementation of the spatially-varying kernel image convolution in multi-cores with OpenMP and graphic processing units (GPUs). Typical speedups over ANSI-C were a factor of 50 and a factor of 1000 over the initial IDL implementation, demonstrating that the techniques are a practical and high impact path to terabyte-per-night image pipelines and petascale processing.Comment: 4 pages. Accepted to IEEE-ICIP 201

A Measurement of the Cosmic-Ray Antiproton Flux and a Search for Antihelium

A balloon-borne instrument has measured the cosmic-ray antiproton flux between 130 and 320 MeV and searched for antihelium between 130 and 370 MeV per nuclear. These particles were selected from the background of normal-matter cosmic rays by combining a selective trigger with a detailed spark chamber visualization of each recorded event. Antiprotons are identified by their characteristic annihilation radiation. Residue from background processes meeting the selection criteria is small. The observed 14 antiprotons yield a measured differential flux of 1.7±0.5X 10^(-4) antiprotons m^(-2) sr(-1) s^(-1)i Mev^(-1) at the top of the atmosphere. The corresponding antiproton/pro-ton ratio is 2.2±0.6X10^(-4), only slightly smaller than the ratio observed by other experiments at higher energies. Thus the antiprotons have a spectral shape similar to the protons, at least down to about 100 MeV. The expected flux of these particles can be calculated under the assumption that they were created by collisions of high-energy cosmic rays with the interstellar gas. Calculations using the standard leaky box model for propagation in the Galaxy predict a flux two orders of magnitude smaller than that observed. A small low-energy flux is predicted due to a kinematic suppression of the production of low-energy antiprotons. The discrepancy between calculations and experiment may be evidence that cosmic-ray protons have passed through substantially more than 5 g cm^(-2) of material during their lifetime. In addition, the combined results from this experiment and previous ones may be evidence for stochastic, energy-changing processes in interstellar space which act upon the secondary antiprotons after their creation. The search for cosmic-ray antihelium sets a 95% confidence level upper limit on the He /He ratio of 2.2 X 10^(-5)

The Measurement of Astronomical Parallaxes With CCD Imaging Cameras on Small Telescopes

Small telescopes equipped with charge-coupled device (CCD) imaging cameras are well suited to introductory laboratory exercises in positional astronomy (astrometry). An elegant example is the determination of the parallax of extraterrestrial objects, such as asteroids. For laboratory exercises suitable for introductory students, the astronomical hardware needs are relatively modest, and under the best circumstances, the analysis requires little more than arithmetic and a microcomputer with image display capabilities. Results from the first such coordinated parallax observations of asteroids ever made are presented. In addition, procedures for several related experiments, involving single-site observations and/or parallaxes of earth-orbiting artificial satellites, are outlined

Photometric and Spectroscopic Observations of SN 1990E in NGC 1035: Observational Constraints for Models of Type II Supernovae

We present 126 photometric and 30 spectral observation of SN 1990E spanning from 12 days before B maximum to 600 days past discovery. These observations show that SN 1990E was of type II-P, displaying hydrogen in its spectrum, and the characteristic plateau in its light curve. SN 1990E is one of the few SNe II which has been well observed before maximum light, and we present evidence that this SN was discovered very soon after its explosion. In the earliest spectra we identify, for the first time, several N II lines. We present a new technique for measuring extinction to SNe II based on the evolution of absorption lines, and use this method to estimate the extinction to SN 1990E, Av=1.5+/-0.3 mag. From our photometric data we have constructed a bolometric light curve for SN 1990E and show that, even at the earliest times, the bolometric luminosity was falling rapidly. We use the late-time bolometric light curve to show that SN 1990E trapped a majority of the gamma rays produced by the radioactive decay of 56Co, and estimate that SN 1990E ejected 0.073 Mo of 56Ni, an amount virtually identical to that of SN 1987A. [excerpt

FUEGO — Fire Urgency Estimator in Geosynchronous Orbit — A Proposed Early-Warning Fire Detection System

Current and planned wildfire detection systems are impressive but lack both sensitivity and rapid response times. A small telescope with modern detectors and significant computing capacity in geosynchronous orbit can detect small (12 m2) fires on the surface of the earth, cover most of the western United States (under conditions of moderately clear skies) every few minutes or so, and attain very good signal-to-noise ratio against Poisson fluctuations in a second. Hence, these favorable statistical significances have initiated a study of how such a satellite could operate and reject the large number of expected systematic false alarms from a number of sources. Here we present both studies of the backgrounds in Geostationary Operational Environmental Satellites (GOES) 15 data and studies that probe the sensitivity of a fire detection satellite in geosynchronous orbit. We suggest a number of algorithms that can help reduce false alarms, and show efficacy on a few. Early detection and response would be of true value in the United States and other nations, as wildland fires continue to severely stress resource managers, policy makers, and the public, particularly in the western US. Here, we propose the framework for a geosynchronous satellite with modern imaging detectors, software, and algorithms able to detect heat from early and small fires, and yield minute-scale detection times

INFRARED STUDIES OF PULSARS

The light curve of the Crab Nebula Pulsar has been studied in the near infrared (.9 {micro}m - 2.4 {micro}m) and found to be similar to the optical light curve except for a shoulder after each main peak. A search for infrared pulsations from other promising candidates was negative, with typical upper limits 3 - 5 magnitudes fainter than the Crab

Global Systems Science Series - A Changing Cosmos Teacher’s Guide

Global Systems Science (GSS) is an interdisciplinary course for high school students that emphasizes how scientists from a wide variety of fields work together to understand significant problems of global impact. The Teacher’s Guide to Global Systems Science provides an overview of the entire series and makes recommendations for how a course in this subject can be structured and presented. It is strongly recommended that teachers consult that guide before beginning a GSS course for their students. The Teachers’ Guide to GSS suggests that every course using this series begin with the unit A New World View, which introduces the entire field of global systems science, and presents four key ideas that thread through the entire series: First, the Earth has tremendously diverse environments, yet it is a single planet that we all call “home.” Second, we can better understand the Earth if we think of it in terms of systems. Third, everything is connected to everything else. And fourth, the goal of global studies is to find out what we can do to sustain life on Planet Earth—now and in the generations to come. A New World View can be followed by any other units in the series, depending on the purpose and context for the entire program

Hands-On Universe and Plans for Large-Scale Internet-Mediated Teacher Training

Hands-On Uni verse (HOU) is. a leading project in science education reform, recognized by teachers, students, and research and educational institutions. Approximately 1000 teachers are using HOU around the world. Key to HOU's philosophy is a network of support by Teacher Resource Agents ("TRA's") who give ongoing support to particpants using the Internet, face-to-face workshops, and other resources. These TRA's collaborate with universities, observatories and informal science education centers in their regions to to engage high school teachers in the innovative educational methods that are highly effective We antiicpate spreading HOU to thousands of schools using the Internet and a "cafeteria plan" of engagement, allowing varying degrees of participation, depending on the needs of the teacher

The Hands-On Universe Project

International audienceHands-On Universe (HOU) is a slowly but steadily growing international endeavor that teaches students and teachers modern astronomy through the acquisition, measurement, and analysis of real images from either the International Virtual Observatory or a developing network of small robotic telescopes. This intrinsically global effort shares data, teachers, scientists, students, telescope sites, lesson plans, teacher training strategies, software, collaborative tools, and other resources. Such resources can be spread both ubiquitously and effectively through modern web-based technologies and traditional means. Astronomy has proven to be a superb mechanism to engender and support worldwide collaboration and cooperation; global HOU currently has embraced collaborators from six continents, and is endeavoring to build telescope resources in Antarctica. HOUer's want to work together and find more and more reasons — as the technology becomes congruent — to be optimistic about the future. An underlying raison d'être of HOU is that students can effectively learn science by actually doing science in "real-world" situations — skills of data analysis, experiment planning, collaboration and cooperation. Such skills are necessary for the future well being of students all over the world