7,086 research outputs found

    Resolve survey Photometry and volume-limited calibration of the Photometric gas fractions technique

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    We present custom-processed ultraviolet, optical, and near-infrared photometry for the REsolved Spectroscopy of a Local VolumE (RESOLVE) survey, a volume-limited census of stellar, gas, and dynamical mass within two subvolumes of the nearby universe (RESOLVE-A and RESOLVE-B). RESOLVE is complete down to baryonic mass 10 ~ 9.1 9.3 - M, probing the upper end of the dwarf galaxy regime. In contrast to standard pipeline photometry (e.g., SDSS), our photometry uses optimal background subtraction, avoids suppressing color gradients, and employs multiple flux extrapolation routines to estimate systematic errors. With these improvements, we measure brighter magnitudes, larger radii, bluer colors, and a real increase in scatter around the red sequence. Combining stellar mass estimates based on our optimized photometry with the nearly complete H I mass census for RESOLVE-A, we create new z = 0 volume-limited calibrations of the photometric gas fractions (PGF) technique, which predicts gas-to-stellar mass ratios (G/S) from galaxy colors and optional additional parameters. We analyze G/S-color residuals versus potential third parameters, finding that axial ratio is the best independent and physically meaningful third parameter. We define a “modified color” from planar fits to G/S as a function of both color and axial ratio. In the complete galaxy population, upper limits on G/S bias linear and planar fits. We therefore model the entire PGF probability density field, enabling iterative statistical modeling of upper limits and prediction of full G/S probability distributions for individual galaxies. These distributions have two-component structure in the red color regime. Finally, we use the RESOLVE-B 21 cm census to test several PGF calibrations, finding that most systematically under- or overestimate gas masses, but the full probability density method performs well

    ECO AND RESOLVE: GALAXY DISK GROWTH IN ENVIRONMENTAL CONTEXT

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    We study the relationships between galaxy environments and galaxy properties related to disk (re)growth, considering two highly complete samples that are approximately baryonic mass limited into the high-mass dwarf galaxy regime, the Environmental COntext catalog (data release herein) and the B-semester region of the REsolved Spectroscopy Of a Local VolumE survey. We quantify galaxy environments using both group identification and smoothed galaxy density field methods. We use by-eye and quantitative morphological classifications plus atomic gas content measurements and estimates. We find that blue early-type (E/S0) galaxies, gas-dominated galaxies, and UV-bright disk host galaxies all become distinctly more common below group halo mass ∌1011.5  M⊙\sim {10}^{11.5}\;{M}_{\odot }, implying that this low group halo mass regime may be a preferred regime for significant disk growth activity. We also find that blue early-type and blue late-type galaxies inhabit environments of similar group halo mass at fixed baryonic mass, consistent with a scenario in which blue early-types can regrow late-type disks. In fact, we find that the only significant difference in the typical group halo mass inhabited by different galaxy classes is for satellite galaxies with different colors, where at fixed baryonic mass red early- and late-types have higher typical group halo masses than blue early- and late-types. More generally, we argue that the traditional morphology–environment relation (i.e., that denser environments tend to have more early-types) can be largely attributed to the morphology-galaxy mass relation for centrals and the color–environment relation for satellites

    Logical Relations for Monadic Types

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    Logical relations and their generalizations are a fundamental tool in proving properties of lambda-calculi, e.g., yielding sound principles for observational equivalence. We propose a natural notion of logical relations able to deal with the monadic types of Moggi's computational lambda-calculus. The treatment is categorical, and is based on notions of subsconing, mono factorization systems, and monad morphisms. Our approach has a number of interesting applications, including cases for lambda-calculi with non-determinism (where being in logical relation means being bisimilar), dynamic name creation, and probabilistic systems.Comment: 83 page

    SPT0346-52: Negligible AGN Activity in a Compact, Hyper-starburst Galaxy at z = 5.7

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    We present Chandra ACIS-S and ATCA radio continuum observations of the strongly lensed dusty, star-forming galaxy SPT-S J034640-5204.9 (hereafter SPT0346-52) at zz = 5.656. This galaxy has also been observed with ALMA, HST, Spitzer, Herschel, APEX, and the VLT. Previous observations indicate that if the infrared (IR) emission is driven by star formation, then the inferred lensing-corrected star formation rate (∌\sim 4500 M_{\sun} yr−1^{-1}) and star formation rate surface density ÎŁSFR\Sigma_{\rm SFR} (∌\sim 2000 M_{\sun} {yr^{-1}} {kpc^{-2}}) are both exceptionally high. It remained unclear from the previous data, however, whether a central active galactic nucleus (AGN) contributes appreciably to the IR luminosity. The {\it Chandra} upper limit shows that SPT0346-52 is consistent with being star-formation dominated in the X-ray, and any AGN contribution to the IR emission is negligible. The ATCA radio continuum upper limits are also consistent with the FIR-to-radio correlation for star-forming galaxies with no indication of an additional AGN contribution. The observed prodigious intrinsic IR luminosity of (3.6 ±\pm 0.3) ×\times 1013^{13} L_{\sun} originates almost solely from vigorous star formation activity. With an intrinsic source size of 0.61 ±\pm 0.03 kpc, SPT0346-52 is confirmed to have one of the highest ÎŁSFR\Sigma_{SFR} of any known galaxy. This high ÎŁSFR\Sigma_{SFR}, which approaches the Eddington limit for a radiation pressure supported starburst, may be explained by a combination of very high star formation efficiency and gas fraction.Comment: 8 pages, 6 figures, accepted for publication in Ap

    The impact of ageing reveals distinct roles for human dentate gyrus and CA3 in pattern separation and object recognition memory

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    © 2017 The Author(s). Both recognition of familiar objects and pattern separation, a process that orthogonalises overlapping events, are critical for effective memory. Evidence is emerging that human pattern separation requires dentate gyrus. Dentate gyrus is intimately connected to CA3 where, in animals, an autoassociative network enables recall of complete memories to underpin object/event recognition. Despite huge motivation to treat age-related human memory disorders, interaction between human CA3 and dentate subfields is difficult to investigate due to small size and proximity. We tested the hypothesis that human dentate gyrus is critical for pattern separation, whereas, CA3 underpins identical object recognition. Using 3 T MR hippocampal subfield volumetry combined with a behavioural pattern separation task, we demonstrate that dentate gyrus volume predicts accuracy and response time during behavioural pattern separation whereas CA3 predicts performance in object recognition memory. Critically, human dentate gyrus volume decreases with age whereas CA3 volume is age-independent. Further, decreased dentate gyrus volume, and no other subfield volume, mediates adverse effects of aging on memory. Thus, we demonstrate distinct roles for CA3 and dentate gyrus in human memory and uncover the variegated effects of human ageing across hippocampal regions. Accurate pinpointing of focal memory-related deficits will allow future targeted treatment for memory loss

    The REDUCE FMR Trial: A Randomized Sham-Controlled Study of Percutaneous Mitral Annuloplasty in Functional Mitral Regurgitation

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    Objectives This study sought to evaluate the effects of the Carillon device on mitral regurgitation severity and left ventricular remodeling. Background Functional mitral regurgitation (FMR) complicates heart failure with reduced ejection fraction and is associated with a poor prognosis. Methods In this blinded, randomized, proof-of-concept, sham-controlled trial, 120 patients receiving optimal heart failure medical therapy were assigned to a coronary sinus-based mitral annular reduction approach for FMR or sham. The pre-specified primary endpoint was change in mitral regurgitant volume at 12 months, measured by quantitative echocardiography according to an intention-to-treat analysis. Results Patients (69.8 ± 9.5 years of age) were randomized to either the treatment (n = 87) or the sham-controlled (n = 33) arm. There were no significant differences in baseline characteristics between the groups. In the treatment group, 73 of 87 (84%) had the device implanted. The primary endpoint was met, with a statistically significant reduction in mitral regurgitant volume in the treatment group compared to the control group (decrease of 7.1 ml/beat [95% confidence interval [CI]: −11.7 to −2.5] vs. an increase of 3.3 ml/beat [95% CI: −6.0 to 12.6], respectively; p = 0.049). Additionally, there was a significant reduction in left ventricular volumes in patients receiving the device versus those in the control group (left ventricular end-diastolic volume decrease of 10.4 ml [95% CI: −18.5 to −2.4] vs. an increase of 6.5 ml [95% CI: −5.1 to 18.2]; p = 0.03 and left ventricular end-systolic volume decrease of 6.2 ml [95% CI: −12.8 to 0.4] vs. an increase of 6.1 ml [95% CI: −1.42 to 13.6]; p = 0.04). Conclusions The Carillon device significantly reduced mitral regurgitant volume and left ventricular volumes in symptomatic patients with functional mitral regurgitation receiving optimal medical therapy. (Carillon Mitral Contour System for Reducing Functional Mitral Regurgitation [REDUCE FMR]; NCT02325830

    Axisymmetric general relativistic hydrodynamics: Long-term evolution of neutron stars and stellar collapse to neutron stars and black holes

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    We report a new implementation for axisymmetric simulation in full general relativity. In this implementation, the Einstein equations are solved using the Nakamura-Shibata formulation with the so-called cartoon method to impose an axisymmetric boundary condition, and the general relativistic hydrodynamic equations are solved using a high-resolution shock-capturing scheme based on an approximate Riemann solver. As tests, we performed the following simulations: (i) long-term evolution of non-rotating and rapidly rotating neutron stars, (ii) long-term evolution of neutron stars of a high-amplitude damping oscillation accompanied with shock formation, (iii) collapse of unstable neutron stars to black holes, and (iv) stellar collapses to neutron stars. The tests (i)--(iii) were carried out with the Γ\Gamma-law equation of state, and the test (iv) with a more realistic parametric equation of state for high-density matter. We found that this new implementation works very well: It is possible to perform the simulations for stable neutron stars for more than 10 dynamical time scales, to capture strong shocks formed at stellar core collapses, and to accurately compute the mass of black holes formed after the collapse and subsequent accretion. In conclusion, this implementation is robust enough to apply to astrophysical problems such as stellar core collapse of massive stars to a neutron star and black hole, phase transition of a neutron star to a high-density star, and accretion-induced collapse of a neutron star to a black hole. The result for the first simulation of stellar core collapse to a neutron star started from a realistic initial condition is also presented.Comment: 28 pages, to appear in PRD 67, 0440XX (2003

    Cesarean Scar Defect Manifestations during Pregnancy and Delivery

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    The cesarean scar is a significant risk factor for the following pregnancies and especially deliveries. In this chapter, we discussed the diagnosis, incidence, detection, manifestations, and prognosis of pregnancy and delivery with cesarean scars. A systematic review of current literature showed that a manifestation of cesarean scars during the following pregnancies is not predictable, in general, although modern visualization technologies could reveal some specific features of scar defects that are associated with complications during pregnancy and delivery. However, there is no factor, which could serve as the main prognostic guide for obstetricians to make a decision for VBAC, thus Edwin Cragin’s phrase “once a cesarean, always a cesarean” has represented the essential healthcare issue over the century. At the moment, the most reasonable measurements to prevent uterine scar complications are reducing the rate of Cesarean Sections, opening the uterus transversely in the lower segment, and stitching the uterus with one layer only continuously using a big needle preferable by Stark technique of Cesarean section

    The Rest-Frame Submillimeter Spectrum of High-Redshift, Dusty, Star-Forming Galaxies

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    We present the average rest-frame spectrum of high-redshift dusty, star-forming galaxies from 250-770GHz. This spectrum was constructed by stacking ALMA 3mm spectra of 22 such sources discovered by the South Pole Telescope and spanning z=2.0-5.7. In addition to multiple bright spectral features of 12CO, [CI], and H2O, we also detect several faint transitions of 13CO, HCN, HNC, HCO+, and CN, and use the observed line strengths to characterize the typical properties of the interstellar medium of these high-redshift starburst galaxies. We find that the 13CO brightness in these objects is comparable to that of the only other z>2 star-forming galaxy in which 13CO has been observed. We show that the emission from the high-critical density molecules HCN, HNC, HCO+, and CN is consistent with a warm, dense medium with T_kin ~ 55K and n_H2 >~ 10^5.5 cm^-3. High molecular hydrogen densities are required to reproduce the observed line ratios, and we demonstrate that alternatives to purely collisional excitation are unlikely to be significant for the bulk of these systems. We quantify the average emission from several species with no individually detected transitions, and find emission from the hydride CH and the linear molecule CCH for the first time at high redshift, indicating that these molecules may be powerful probes of interstellar chemistry in high-redshift systems. These observations represent the first constraints on many molecular species with rest-frame transitions from 0.4-1.2mm in star-forming systems at high redshift, and will be invaluable in making effective use of ALMA in full science operations.Comment: 19 pages, 10 figures (2 in appendices); accepted for publication in Ap

    The redshift distribution of dusty star forming galaxies from the SPT survey

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    We use the Atacama Large Millimeter/submillimeter Array (ALMA) in Cycle 1 to determine spectroscopic redshifts of high-redshift dusty star-forming galaxies (DSFGs) selected by their 1.4mm continuum emission in the South Pole Telescope (SPT) survey. We present ALMA 3mm spectral scans between 84-114GHz for 15 galaxies and targeted ALMA 1mm observations for an additional eight sources. Our observations yield 30 new line detections from CO, [CI] , [NII] , H_2O and NH_3. We further present APEX [CII] and CO mid-J observations for seven sources for which only a single line was detected in spectral-scan data from ALMA Cycle 0 or Cycle 1. We combine the new observations with previously published and new mm/submm line and photometric data of the SPT-selected DSFGs to study their redshift distribution. The combined data yield 39 spectroscopic redshifts from molecular lines, a success rate of >85%. Our sample represents the largest data set of its kind today and has the highest spectroscopic completeness among all redshift surveys of high-z DSFGs. The median of the redshift distribution is z=3.9+/-0.4, and the highest-redshift source in our sample is at z=5.8. We discuss how the selection of our sources affects the redshift distribution, focusing on source brightness, selection wavelength, and strong gravitational lensing. We correct for the effect of gravitational lensing and find the redshift distribution for 1.4mm-selected sources with a median redshift of z=3.1+/-0.3. Comparing to redshift distributions selected at shorter wavelengths from the literature, we show that selection wavelength affects the shape of the redshift distribution
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