Marc Postman - Academia.edu (original) (raw)

Papers by Marc Postman

We report on the development of TA-DA, a general Tool for Astrophysical Data Analysis. TA-DA is i... more We report on the development of TA-DA, a general Tool for Astrophysical Data Analysis. TA-DA is intended as a powerful, integrated web service to significantly simplify the process of comparing calibrated astrophyiscal data with theoretical stellar evolutionary models. It is built upon the Synphot (for synthetic photometry) and Chorizos (a Bayesian multi-parametric chi-squared fitting algorithm) packages. TA-DA will allow to easily and reliably compute a variety of fundamental observables including synthetic photometry from theoretical spectral energy distributions, color corrections, and bandpass transformations. It will also support the cross-calibration of photometry from different archives, analysis of individual SEDs, statistical analysis of HR diagrams and self-consistent prediction of astronomical performance.

Observatory Operations to Optimize Scientific Return, 1998

ABSTRACT The Hubble Data Archive at the Space Telescope Science Institute contains over 4.3 TB of... more ABSTRACT The Hubble Data Archive at the Space Telescope Science Institute contains over 4.3 TB of data, primarily for the Hubble Space Telescope, but also from complementary space- based and ground-based facilities. We are in the process of upgrading and generalizing many of the HDA's component system, developing tools to provide more integrated access to the HDA holdings, and working with other major data providing organizations to implement global data location services for astronomy and other space science disciplines. This paper describes the key elements of our archiving and data distribution systems, including a planned transition to DVD media, data compression, data segregation, on-the-fly calibration, an engineering data warehouse, and distributed search and retrieval facilities.

Science (New York, N.Y.), Jan 6, 2015

In 1964, Refsdal hypothesized that a supernova whose light traversed multiple paths around a stro... more In 1964, Refsdal hypothesized that a supernova whose light traversed multiple paths around a strong gravitational lens could be used to measure the rate of cosmic expansion. We report the discovery of such a system. In Hubble Space Telescope imaging, we have found four images of a single supernova forming an Einstein cross configuration around a redshift z = 0.54 elliptical galaxy in the MACS J1149.6+2223 cluster. The cluster's gravitational potential also creates multiple images of the z = 1.49 spiral supernova host galaxy, and a future appearance of the supernova elsewhere in the cluster field is expected. The magnifications and staggered arrivals of the supernova images probe the cosmic expansion rate, as well as the distribution of matter in the galaxy and cluster lenses.

ABSTRACT Galaxy clusters play a key role in testing cosmological models and in constraining the p... more ABSTRACT Galaxy clusters play a key role in testing cosmological models and in constraining the properties of dark matter. One of these key tests is the mass density profile of clusters - the concentration-mass relation. There is a reported tension between the observed concentration-mass relation and the one theoretically expected using simulated galaxy clusters, where the observed clusters appear to have higher concentration than simulated clusters of similar total mass. In The Cluster Lensing And Supernova survey with Hubble (CLASH), we use different and independent techniques to estimate the mass distribution in clusters. The comparison between different techniques offers an observational test of the techniques and understanding of the systematics. In this work, we estimate the concentration-mass relation for about 8 (at the 0.2< z &;lt; 0.6 redshift range) of the 20 X-ray selected CLASH clusters using galaxy dynamics. We use a unique spectroscopic data set with more than about 300 cluster members per cluster. Finally, we compare our results to the theoretical expected ones and to the estimations derived using the lensing technique.

The Astrophysical Journal, 2015

Space Telescopes and Instrumentation 2014: Optical, Infrared, and Millimeter Wave, 2014

Astronomy & Astrophysics, 2014

Space Telescopes and Instrumentation 2010: Optical, Infrared, and Millimeter Wave, 2010

The Astrophysical Journal, 2014

The Astrophysical Journal, 2012

The Astronomical Journal, 2000

The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept for an 8-meter to 16... more The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept for an 8-meter to 16-meter UVOIR space observatory for launch in the 2025-2030 era. ATLAST will allow astronomers to answer fundamental questions at the forefront of modern astronphysics, including "Is there life elsewhere in the Galaxy?" We present a range of science drivers that define the main performance requirements for

astro.princeton.edu

2Department of Astronomy, University of Washington, Seattle, WA 98195; ivezic@astro.washington.ed... more 2Department of Astronomy, University of Washington, Seattle, WA 98195; ivezic@astro.washington.edu ... 3University League Nursery School, Princeton, NJ 08544, USA ... 42555 NE 85th Street, Seattle, WA 98115, USA ... A description of the SDSS image ...

The Cluster Lensing And Supernova survey with Hubble (CLASH) is a 524-orbit multi-cycle treasury ... more The Cluster Lensing And Supernova survey with Hubble (CLASH) is a 524-orbit multi-cycle treasury program to use the gravitational lensing properties of 25 galaxy clusters to accurately constrain their mass distributions. The survey, described in detail in this paper, will definitively establish the degree of concentration of dark matter in the cluster cores, a key prediction of CDM. The CLASH