Nick Weir

I2M Solutions, LLC

We used scans of sky survey plates available at STScl to look for the presence of multiple-image QSOs which could be due to gravitational lensing. We extracted about 1500 fields, each having 5 arcmin in size, around QSOs brighter than m v = 18. No lenses have been found so far. We found several cases of galaxies close in projection (within a few ar...

The Bayesian framework for model comparison and regularisation is demonstrated by studying interpolation and classification problems modelled with both linear and non--linear models. This framework quantitatively embodies `Occam's razor'. Over--complex and under-- regularised models are automatically inferred to be less probable, even though their...

The value of scientific digital-image libraries seldom lies in the pixels of images. For large collections of images, such as those resulting from astronomy sky surveys, the typical useful product is an online database cataloging entries of interest. The authors focus on the automation of the cataloging effort of a major sky survey and the availabi...

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We describe the design and implementation of a software system for producing, managing, and analyzing catalogs from the digital scans of the Second Palomar Observatory Sky Surveys. The system (SKICAT) integrates new and existing packages for performing the full sequence of tasks from raw pixel processing, to object classification, to the matching o...

. We report on the preliminary results of experiments using a Bayesian cluster method to cluster objects present in photographic images of the POSS-II. Our goal is to explore the power of unsupervised learning techniques to classify objects meaningfully, and perhaps to discover previously unrecognized object categories in digital sky surveys. Our p...

In our first analysis of the Digitized Second Palomar Observatory Sky Survey (DPOSS), we examine galaxy counts on an overlapping set of four survey fields near the North Galactic Pole, in both the J and F passbands. Through detailed simulations of a subset of these data, we were able to analyze systematic aspects of our detection and photometric pr...

We are conducting a survey to identity z > 4 quasars using a digital version of the Second Palomar Sky Survey. The plates are taken in the photographic JFN bands and calibrated to the Gunn-Thuan gri system, making these data suitable for a multicolor search for quasars in the redshift range of 4.0 <~ z <~ 4.8. A new software package, SKICAT, was de...

We describe the automated object classification method implemented in the Sky Image Cataloging and Analysis Tool (SKICAT) and applied to the Digitized Second Palomar Observatory Sky Survey (DPOSS). This classification technique was designed with two purposes in mind: first, to classify objects in DPOSS to the faintest limits of the data; second, to...

In areas as diverse as earth remote sensing, astronomy, and medical imaging, image acquisition technology has undergone tremendous improvements in recent years. The vast amounts of scientific data are potential treasure-troves for scientific investigation and analysis. Unfortunately, advances in our ability to deal with this volume of data in an ef...

We present preliminary results of the application of clustering analysis and unsupervised classification techniques to the catalogs of objects from the digital scans of the POSS-II. The data set consists of matched catalogs of approximately 8 million objects, for each of which a number of attributes have been measured. They are from 15 sky survey f...

Digitization of the Second Palomar Observatory Sky Survey (POSS-II) is now in progress at STScI. The resulting data set, the Palomar-STScI Digital Sky Survey (DPOSS), will consist of about 3 TB of pixel data. In order to extract useful information from this data set quickly, uniformly, and efficiently, we have developed a software system to catalog...

We describe the application of decision tree based classification techniques to the development of an automated tool for the reduction of a large scientific data set. The 2nd Palomar Observatory Sky Survey (POSS-II) will provide a comprehensive coverage of the northern celestial hemisphere in the form of digitized photographic plates containing on...

Analysis of the Palomar-STScI Digital Sky Survey (DPOSS) has only begun. The system we developed for this task, called SKICAT, is used to generate star and galaxy catalogs from the raw plate scans and CCD calibration frames. As a part of the initial scientific verification tests of the system, here we present results for the galaxy angular two-poin...

Digitization of the Second Palomar Observatory Sky Survey (POSS-II) is now in progress at STScI. The resulting data set, the Palomar-STScI Digital Sky Survey (DPOSS), will consist of ~ 3 TB of pixel data, or ~ 1 GB/plate (1 arcsec pixels, 2 bytes/pixel, 23040(2) pixels/plate, ~ 900 survey fields in 3 colors). We have developed a software system to...

We have developed a software system call SKICAT for the reduction and analysis of the Palomar-STScI Digital Sky Survey (DPOSS). As a part of the initial scientific verification tests of the system, we measured star and galaxy counts over a limited area near the North Galactic Pole, covering 4 adjacent Survey fields, or ~ 100 square degrees. The cou...

ABSTRACT We describe,the application,of machine,learning,and state-of-the-art database,management,technology,to the development,of an automated tool for the reduction,and analysis of a large astronomical,data set. The 3 terabytes,worth,of images,are,expected,to contain,on the order of 5 x 107 galaxies,and,5 x 108 stars. For the primary,scientific,a...

We describe the application of an Artificial Intelligence machine learning techniques to the development of an automated tool for the reduction of a large scientific data set. The 2nd Mt. Palomar Northern Sky Survey is nearly completed. This survey provides comprehensive coverage of the northern celestial hemisphere in the form of photographic plat...

We have developed a software system for the reduction and analysis of the Palomar-STScI Digital Sky Survey (cf. B.A.A.S. 23, p. 1434, and B.A.A.S. 24, pp. 741, 750, and 1139). This system, named SKICAT, uses a number of image processing and machine-learning based modules, and conducts pipeline processing of the plate scans, from raw pixel measureme...

We describe the design and applications of a software system for analyzing the digital scans of the Second Palomar Observatory Sky Survey (POSS-II). The system (SKICAT) integrates new and existing packages for performing the full spectrum of tasks from raw pixel processing, to object classification, to the photometric matching of multiple Schmidt p...

Images of the multiple-component radio source B1422+231 at 2.2 microns show the structure of this source to be essentially the same at radio and infrared frequencies. The most natural explanation for this achromatic structure is gravitational lensing.

We describe the application of machine classification techniques to the development of an automated tool for the reduction of a large scientific data set. The 2nd Palomer Observatory Sky Survey is nearly completed. This survey provides comprehensive coverage of the northern celestial hemisphere in the form of photographic plates. The plates are bei...

We report the results of deep optical and IR imaging, astrometry, and spectroscopy of the recently identified, probable Einstein ring source 1830–211. While no definitive counterpart has been identified, several faint objects have been found in the proximity of the radio positions. The brightest object (∼ 20 mag in the red) is nearly coincident wit...

The program to digitize the second Palomar sky survey (POSS-II) is based on scans done with the same modified PDS microdensitometers that were used for the Guide Star Catalog. An approximately Gaussian aperture with a nominal size of 30 microns\ (FW at e(-2) ) is used with a sampling interval of 15 microns. The full rasters, 23,040 pixels square, o...

We describe and present initial results of a system for constructing and analyzing catalogs derived from the Palomar Observatory-ST ScI Digital Sky Survey. Using a combination of existing packages (FOCAS and SAS) and special purpose software, we are developing a system for converting the raw digitized plate images (23,040(2) pixels) into classified...

The second Palomar sky survey (POSS-II) is now under way, using the 48-inch Oschin Schmidt telescope at Palomar Observatory. When completed, the photographic survey will consist of 896 fields spaced at 5(deg) intervals, covering the entire northern sky in three bands: green (IIIa-J), red (IIIa-F), and near-IR (IV-N). At the moment, approximately 50...

We describe an extension to the maximum entropy (MaxEnt) method of image restoration which may improve results for images with multiple scales of pixel-to-pixel correlation. The technique is a straightforward generalization of modern MaxEnt methods, whereby one solves not just for a single restored image, but for multiple images with varying degree...

We have compared the use of so-called ‘parametric’ and ‘resolution’-based object classifiers on digitized images from the Second Palomar Observatory Sky Survey. We find that the latter approach, involving the fitting of two-dimensional templates to each detected object, can provide reasonable discrimination at levels approximately a magnitude faint...

We used scans of sky survey plates available at STScl to look for the presence of multiple-image QSOs which could be due to gravitational lensing. We extracted about 1500 fields, each having 5 arcmin in size, around QSOs brighter than m_v = 18. No lenses have been found so far. We found several cases of galaxies close in projection (within a few ar...

The capabilities of the Faint Object Camera (FOC) and the Wide Field Camera (WFC) are assessed on the basis of a brief program of single-orbit images of medium-faint galaxies. The FOC yielded a good resolved image of a compact galaxy at a blue magnitude J of 20.5 in a single-orbit exposure. WFC images have a survey capability that can include many...

Raw and maximum entropy restored images of the quasar pair (gravitational lens candidate) 2345 + 007 A and B are presented. Restorations are performed using an implementation of the Gull-Skilling MEMSYS-3 package of maximum entropy method subroutines designed to achieve subpixel resolution in certain data regimes. Extensive simulations of the data...

A program of high resolution infrared imaging at Palomar Observatory, is presented. The use of nonredundant masks both as an imaging technique and as a method of analyzing various aspects of the imaging system are investigated. In particular, the technique is applied to a bright star and binary system using a three-hole mask. The method is useful f...

A program of high resolution infrared imaging at Palomar Observatory, is presented. The use of nonredundant masks both as an imaging technique and as a method of analyzing various aspects of the imaging system are investigated. In particular, the technique is applied to a bright star and binary system using a three-hole mask. The method is useful f...

Diffraction-limited infrared images of three binary stars reconstructed using speckle imaging techniques are presented. Three methods of recovering the objects' Fourier amplitudes are compared, Fourier deconvolution, projection onto convex sets, and CLEAN. The objects' Fourier phases are retrieved via bispectral analysis. It is shown that the quali...

We propose a heuristic model for the origin of the cosmic submillimeter background (SMB), reported by the Nagoya-Berkeley collaboration. The SMB is interpreted as a direct signature of an epoch of (initial) galaxy formation at z ~ 10-15. The sources of the SMB are proposed to be dust-shrouded starburst protogalaxies, similar to the luminous IRAS ga...

A heuristic model for the origin of the cosmic submillimeter background (SMB), reported by the Nagoya-Berkeley collaboration, is proposed. The SMB is interpreted as a direct signature of an epoch of (initial) galaxy formation at zgf of about 10 - 15. The sources of the SMB are proposed to be dust-shrouded starburst protogalaxies, similar to the lum...

The effects of variations in evolutionary model parameters on the K-band Hubble diagram are explored and the predictions of the older and the newer population synthesis models are compared. The predictions of the old and the new Bruzual models differ significantly; this is traceable to a problem in combining the input stellar libraries. The new mod...

We propose a heuristic model for the origin of the cosmic submillimeter background (SMB), reported by the Nagoya-Berkeley collaboration. The SMB is interpreted as a direct signature of an epoch of (initial) galaxy formation at z_(gf) ~ 10 - 15. The sources of the SMB are proposed to be dust-shrouded starburst protogalaxies, similar to the luminous...

We explore the effects of variations in evolutionary model parameters on the K-band Hubble diagram, and compare the prediction of the older and the newer population synthesis models. The predictions of the old and the new Bruzual models differ significantly; this is tractable to a problem in combining the input stellar libraries. The new models are...

Long-slit CCD spectra of 19 stellar objects selected from the Case Low-Dispersion Northern Sky Survey are presented. Thirteen of them are quasars, ranging in redshift from 0.0786 to 2.67, with a median redshift of 2. CSO 203 is a broad absorption-line quasar, and CSO 38 may have substantial associated absorption in the cores of emission lines. Seve...

We describe the application of machine learning and state-of-the-art database management technology to the development of an automated tool for the reduction and analysis of a large astronomical data set. The 3 terabytes worth of images are expected to contain on the order of 5x107 galaxies and 5x108 stars. For the primary scientific analysis of th...