36 research outputs found

    Checks And Balances: 2015 Update

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    Checking accounts are a vital financial tool, utilized by 9 in 10 American households. This report provides the third annual evaluation of disclosure, overdraft, and dispute resolution policies and practices of 45 of the nation's 50 largest retail banks, totaling 66 percent of all domestic deposit volume. Pew's Model Summary Disclosure Box for Checking Accounts served as the template for rating each bank's disclosure documents to determine best or good practices for overdraft and dispute resolution. Additionally, this report identified trends among the 32 institutions examined in all three Checks and Balances reports to date. To ensure that all checking accounts are safe and transparent, Pew has also developed a set of policy recommendations and urges the Consumer Financial Protection Bureau to incorporate these policies in new rules on overdraft practices and arbitration clauses

    The Complex Story of American Debt

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    This report explores a key element of wealth: household debt. Debt is sometimes acquired for mobility-enhancing purposes, such as to pay for college or purchase a home. But debt can also serve as a stopgap for families to cover regular expenses or deal with financial emergencies, especially if their savings are not sufficient. The type and amount of debt that households carry contribute to their wealth and their overall financial health

    Early Planet Formation in Embedded Disks (eDisk). VIII. A Small Protostellar Disk around the Extremely Low-Mass and Young Class 0 Protostar, IRAS 15398-3359

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    Protostellar disks are a ubiquitous part of the star formation process and the future sites of planet formation. As part of the Early Planet Formation in Embedded Disks (eDisk) large program, we present high-angular resolution dust continuum (40\sim40\,mas) and molecular line (150\sim150\,mas) observations of the Class 0 protostar, IRAS 15398-3359. The dust continuum is small, compact, and centrally peaked, while more extended dust structures are found in the outflow directions. We perform a 2D Gaussian fitting to find the deconvolved size and 2σ2\sigma radius of the dust disk to be 4.5×2.8au4.5\times2.8\,\mathrm{au} and 3.8au3.8\,\mathrm{au}, respectively. We estimate the gas+dust disk mass assuming optically thin continuum emission to be 0.61.8Mjup0.6-1.8\,M_\mathrm{jup}, indicating a very low-mass disk. The CO isotopologues trace components of the outflows and inner envelope, while SO traces a compact, rotating disk-like component. Using several rotation curve fittings on the PV diagram of the SO emission, the lower limits of the protostellar mass and gas disk radius are 0.022M0.022\,M_\odot and 31.2au31.2\,\mathrm{au} from our Modified 2 single power-law fitting. A conservative upper limit of the protostellar mass is inferred to be 0.1M0.1\,M_\odot. The protostellar mass-accretion rate and the specific angular momentum at the protostellar disk edge are found to be between 1.36.1×106Myr11.3-6.1\times10^{-6}\,M_\odot\,\mathrm{yr^{-1}} and 1.23.8×104kms1pc1.2-3.8\times10^{-4}\,\mathrm{km\,s^{-1}\,pc}, respectively, with an age estimated between 0.47.5×1040.4-7.5\times10^{4}\,yr. At this young age with no clear substructures in the disk, planet formation would likely not yet have started. This study highlights the importance of high-resolution observations and systematic fitting procedures when deriving dynamical properties of deeply embedded Class 0 protostars.Comment: 28 pages, 16 figures. Accepted for publication in ApJ as one of the first-look papers of the eDisk ALMA Large Progra

    Early Planet Formation in Embedded Disks (eDisk) XII: Accretion streamers, protoplanetary disk, and outflow in the Class I source Oph IRS63

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    We present ALMA observations of the Class I source Oph IRS63 in the context of the Early Planet Formation in Embedded Disks (eDisk) large program. Our ALMA observations of Oph IRS63 show a myriad of protostellar features, such as a shell-like bipolar outflow (in 12^{12}CO), an extended rotating envelope structure (in 13^{13}CO), a streamer connecting the envelope to the disk (in C18^{18}O), and several small-scale spiral structures seen towards the edge of the dust continuum (in SO). By analyzing the velocity pattern of 13^{13}CO and C18^{18}O, we measure a protostellar mass of M=0.5±0.2\rm M_\star = 0.5 \pm 0.2 ~M\rm M_\odot and confirm the presence of a disk rotating at almost Keplerian velocity that extends up to 260\sim260 au. These calculations also show that the gaseous disk is about four times larger than the dust disk, which could indicate dust evolution and radial drift. Furthermore, we model the C18^{18}O streamer and SO spiral structures as features originating from an infalling rotating structure that continuously feeds the young protostellar disk. We compute an envelope-to-disk mass infall rate of 106\sim 10^{-6}~Myr1\rm M_\odot \, yr^{-1} and compare it to the disk-to-star mass accretion rate of 108\sim 10^{-8}~Myr1\rm M_\odot \, yr^{-1}, from which we infer that the protostellar disk is in a mass build-up phase. At the current mass infall rate, we speculate that soon the disk will become too massive to be gravitationally stable.Comment: 26 pages and 17 figure

    Early Planet Formation in Embedded Disks (eDisk) III: A first high-resolution view of sub-mm continuum and molecular line emission toward the Class 0 protostar L1527 IRS

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    Studying the physical and chemical conditions of young embedded disks is crucial to constrain the initial conditions for planet formation. Here, we present Atacama Large Millimeter/submillimeter Array (ALMA) observations of dust continuum at \sim0.06" (8 au) resolution and molecular line emission at \sim0.17" (24 au) resolution toward the Class 0 protostar L1527 IRS from the Large Program eDisk (Early Planet Formation in Embedded Disks). The continuum emission is smooth without substructures, but asymmetric along both the major and minor axes of the disk as previously observed. The detected lines of 12^{12}CO, 13^{13}CO, C18^{18}O, H2_2CO, c-C3_3H2_2, SO, SiO, and DCN trace different components of the protostellar system, with a disk wind potentially visible in 12^{12}CO. The 13^{13}CO brightness temperature and the H2_2CO line ratio confirm that the disk is too warm for CO freeze out, with the snowline located at \sim350 au in the envelope. Both molecules show potential evidence of a temperature increase around the disk-envelope interface. SO seems to originate predominantly in UV-irradiated regions such as the disk surface and the outflow cavity walls rather than at the disk-envelope interface as previously suggested. Finally, the continuum asymmetry along the minor axis is consistent with the inclination derived from the large-scale (100" or 14,000 au) outflow, but opposite to that based on the molecular jet and envelope emission, suggesting a misalignment in the system. Overall, these results highlight the importance of observing multiple molecular species in multiple transitions to characterize the physical and chemical environment of young disks.Comment: 27 pages, 16 figures, 2 tables, 10 pages appendix with 12 figures. Accepted for publication in ApJ as one of the first-look papers of the eDisk ALMA Large Progra

    Early Planet Formation in Embedded Disks (eDisk). VII. Keplerian Disk, Disk Substructure, and Accretion Streamers in the Class 0 Protostar IRAS 16544-1604 in CB 68

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    We present observations of the Class 0 protostar IRAS 16544-1604 in CB 68 from the ''Early Planet Formation in Embedded Disks (eDisk)'' ALMA Large program. The ALMA observations target continuum and lines at 1.3-mm with an angular resolution of \sim5 au. The continuum image reveals a dusty protostellar disk with a radius of \sim30 au seen close to edge-on, and asymmetric structures both along the major and minor axes. While the asymmetry along the minor axis can be interpreted as the effect of the dust flaring, the asymmetry along the major axis comes from a real non-axisymmetric structure. The C18^{18}O image cubes clearly show the gas in the disk that follows a Keplerian rotation pattern around a \sim0.14 MM_{\odot} central protostar. Furthermore, there are \sim1500 au-scale streamer-like features of gas connecting from North-East, North-North-West, and North-West to the disk, as well as the bending outflow as seen in the 12^{12}CO (2-1) emission. At the apparent landing point of NE streamer, there are SO (65_5-54_4) and SiO (5-4) emission detected. The spatial and velocity structure of NE streamer can be interpreted as a free-falling gas with a conserved specific angular momentum, and the detection of the SO and SiO emission at the tip of the streamer implies presence of accretion shocks. Our eDisk observations have unveiled that the Class 0 protostar in CB 68 has a Keplerian rotating disk with flaring and non-axisymmetric structure associated with accretion streamers and outflows.Comment: 30 pages, 24 figures, accepted for publication in The Astrophysical Journal as one of the first-look papers of the eDisk ALMA Large Progra

    Early Planet Formation in Embedded Disks (eDisk). I. Overview of the Program and First Results

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    We present an overview of the Large Program, ``Early Planet Formation in Embedded Disks (eDisk)'', conducted with the Atacama Large Millimeter/submillimeter Array (ALMA). The ubiquitous detections of substructures, particularly rings and gaps, in protoplanetary disks around T Tauri stars raise the possibility that at least some planet formation may have already started during the embedded stages of star formation. In order to address exactly how and when planet formation is initiated, the program focuses on searching for substructures in disks around 12 Class 0 and 7 Class I protostars in nearby (<< 200 pc) star-forming regions through 1.3 mm continuum observations at a resolution of 7\sim7 au (0.04"). The initial results show that the continuum emission, mostly arising from dust disks around the sample protostars, has relatively few distinctive substructures, such as rings and spirals, in marked contrast to Class II disks. The dramatic difference may suggest that substructures quickly develop in disks when the systems evolve from protostars to Class II sources or alternatively that high optical depth of the continuum emission could obscure internal structures. Kinematic information obtained through CO isotopologue lines and other lines reveals the presence of Keplerian disks around protostars, providing us with crucial physical parameters, in particular, the dynamical mass of the central protostars. We describe the background of the eDisk program, the sample selection and their ALMA observations, the data reduction, and also highlight representative first-look results.Comment: This is a publication of a series of eDisk ALMA large program first-look paper

    The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

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    The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure
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