1,646 research outputs found

    PHAT Stellar Cluster Survey I. Year 1 Catalog and Integrated Photometry

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    The Panchromatic Hubble Andromeda Treasury (PHAT) survey is an on-going Hubble Space Telescope (HST) multi-cycle program to obtain high spatial resolution imaging of one-third of the M31 disk at ultraviolet through near-infrared wavelengths. In this paper, we present the first installment of the PHAT stellar cluster catalog. When completed, the PHAT cluster catalog will be among the largest and most comprehensive surveys of resolved star clusters in any galaxy. The exquisite spatial resolution achieved with HST has allowed us to identify hundreds of new clusters that were previously inaccessible with existing ground-based surveys. We identify 601 clusters in the Year 1 sample, representing more than a factor of four increase over previous catalogs within the current survey area (390 arcmin^2). This work presents results derived from the first \sim25% of the survey data; we estimate that the final sample will include \sim2500 clusters. For the Year 1 objects, we present a catalog with positions, radii, and six-band integrated photometry. Along with a general characterization of the cluster luminosities and colors, we discuss the cluster luminosity function, the cluster size distributions, and highlight a number of individually interesting clusters found in the Year 1 search.Comment: 26 pages, 22 figures, Accepted by Ap

    Brady Statute Data: Establishing Noncriminal Classifications for the Alaska Department of Public Safety

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    The Brady Handgun Violence Prevention Act of 1993 prohibits the purchase of firearms by persons in certain noncriminal categories. These reports describe potential data sources for the identification of mental committments, addicted substance abusers, illegal aliens, and persons who have been the subject of a domestic violence restraining order and discusses possible procedures, problems, and solutions associated with data collection for the purpose of Brady background checks. Lack of infrastructure for collecting certain types of data, incompleteness of information, and state constitutional protections, including the guarantee of privacy, are the chief obstacles to completely meeting the provisions of the Brady Act in Alaska.Bureau of Justice Statistics, United States Department of Justice Grant No. 96-RU-RX-K026Background / Needs and Benefits / Goals and Objectives / Project Design / Findings by Classification / Conclusio

    The Planck mission

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    These lecture from the 100th Les Houches summer school on "Post-planck cosmology" of July 2013 discuss some aspects of the Planck mission, whose prime objective was a very accurate measurement of the temperature anisotropies of the Cosmic Microwave Background (CMB). We announced our findings a few months ago, on March 21st^{st}, 2013. I describe some of the relevant steps we took to obtain these results, sketching the measurement process, how we processed the data to obtain full sky maps at 9 different frequencies, and how we extracted the CMB temperature anisotropies map and angular power spectrum. I conclude by describing some of the main cosmological implications of the statistical characteristics of the CMB we found. Of course, this is a very much shortened and somewhat biased view of the \Planck\ 2013 results, written with the hope that it may lead some of the students to consult the original papers.Comment: 53 p.-34 fig; for spacetime consideration, the file here is not paying justice to the actual thing; a closer approximation of it can be found at https://www.researchgate.net/profile/Francois_Bouchet/publication/262004262_The_Planck_Mission/file/e0b495363b042e81dd.pd

    The Panchromatic Hubble Andromeda Treasury

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    The Panchromatic Hubble Andromeda Treasury (PHAT) is an on-going HST Multicycle Treasury program to image ~1/3 of M31's star forming disk in 6 filters, from the UV to the NIR. The full survey will resolve the galaxy into more than 100 million stars with projected radii from 0-20 kpc over a contiguous 0.5 square degree area in 828 orbits, producing imaging in the F275W and F336W filters with WFC3/UVIS, F475W and F814W with ACS/WFC, and F110W and F160W with WFC3/IR. The resulting wavelength coverage gives excellent constraints on stellar temperature, bolometric luminosity, and extinction for most spectral types. The photometry reaches SNR=4 at F275W=25.1, F336W=24.9, F475W=27.9, F814W=27.1, F110W=25.5, and F160W=24.6 for single pointings in the uncrowded outer disk; however, the optical and NIR data are crowding limited, and the deepest reliable magnitudes are up to 5 magnitudes brighter in the inner bulge. All pointings are dithered and produce Nyquist-sampled images in F475W, F814W, and F160W. We describe the observing strategy, photometry, astrometry, and data products, along with extensive tests of photometric stability, crowding errors, spatially-dependent photometric biases, and telescope pointing control. We report on initial fits to the structure of M31's disk, derived from the density of RGB stars, in a way that is independent of the assumed M/L and is robust to variations in dust extinction. These fits also show that the 10 kpc ring is not just a region of enhanced recent star formation, but is instead a dynamical structure containing a significant overdensity of stars with ages >1 Gyr. (Abridged)Comment: 48 pages including 22 pages of figures. Accepted to the Astrophysical Journal Supplements. Some figures slightly degraded to reduce submission siz

    Legislative Underwrites

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    This article introduces a widespread but virtually unacknowledged practice in Congress and state legislatures. Not only do legislatures override judicial decisions as part of an interbranch dialogue when they disagree with judicial rulings and doctrine, they also underwrite judicial decisions when they agree with those rulings. For all the literature on the adversarial communication evidenced through legislative overriding, there is not a single paper devoted to legislative underwrites that reflect more collaborative dimensions of the interbranch dialogue. This article begins to fill that void, and in so doing it frames practical and theoretical lessons for legislative, judicial, and scholarly audiences. More specifically, the article defines the contours of an underwrite and identifies the diversity of underwrite initiatives in Congress and state legislatures. It then normatively evaluates costs and benefits that might flow from a more self-conscious approach to underwrites, analyzing these pros and cons as they operate at pragmatic, doctrinal, and conceptual levels. It also examines certain vulnerabilities to the practice that may limit the scope and meaning of underwrites as applied by “downstream” statutory interpreters. Finally, the article explores the interplay between underwrites and key interpretive doctrines that invoke legislative silence—notably, statutory stare decisis and the re-enactment rule. In that connection, it suggests certain doctrinal and institutional settings in which underwrites may be especially valuable

    Request for proposals for industry review

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    The purpose of this Request for Proposals (RFP) is to select a Proposer to perform the Project services described in this RFP. SCDOT desires that this Project be constructed in a very efficient and timely manner. This proposal is for a design-build project for an emergency bridge project for Anderson and York Counties

    Planck 2013 results. VI. High Frequency Instrument data processing

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    We describe the processing of the 531 billion raw data samples from the High Frequency Instrument (hereafter HFI), which we performed to produce six temperature maps from the first 473 days of Planck-HFI survey data. These maps provide an accurate rendition of the sky emission at 100, 143, 217, 353, 545, and 857 GHz with an angular resolution ranging from 9.7 to 4.6 arcmin. The detector noise per (effective) beam solid angle is respectively, 10, 6, 12 and 39 microKelvin in HFI four lowest frequency channel (100--353 GHz) and 13 and 14 kJy/sr for the 545 and 857 GHz channels. Using the 143 GHz channel as a reference, these two high frequency channels are intercalibrated within 5% and the 353 GHz relative calibration is at the percent level. The 100 and 217 GHz channels, which together with the 143 GHz channel determine the high-multipole part of the CMB power spectrum (50 < l <2500), are intercalibrated at better than 0.2 %

    Request for proposals final with addendum 1

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    The purpose of this Request for Proposals (RFP) is to select a Proposer to perform the Project services described in this RFP. SCDOT desires that this Project be constructed in a very efficient and timely manner. This proposal is for a design-build project for a Closed and Load Restricted Bridge Package for Abbeville, Greenwood, Laurens, McCormick, Newberry, and Saluda Counties
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