80 research outputs found

    Two-Step 3D-Guided Supramalleolar Osteotomy to Treat Varus Ankle osteoarthritis

    Get PDF
    Background: Success of valgus-type supramalleolar osteotomy (SMOT) depends on adequate correction of malalignment, which can be hard to achieve with current 2-dimensional (2D) planning and operative techniques. A personalized digital 3-dimensional (3D) workflow to virtually plan and perform a 2-step 3D-guided medial opening (MO) SMOT has the potential to improve precision of correction. Methods: Computed tomography (CT)-based Proplan medical 3D models were made to virtually plan the desired MO SMOT, and exported to 3-Matic medical to develop patient-specific 2-step cutting and wedge guides. Workflow accuracy was tested in this limited clinical pilot study (3 patients) by comparing the virtual planned position of the osteotomized distal tibial fragment with the I -year post-MO SMOT configuration. Two millimeters or less translation deviation in every plane was defined as accurate. Results: Primary outcome analysis of the osteotomized distal tibial fragment deviation showed a median translation in all planes of 0.7 (range 0-8.2) mm (interquartile range 1.55) with an excellent interrater reliability of the measurements (intraclass correlation coefficient 0.998). There was a strong reduction in ankle pain as reflected by an increase of the AOFAS-AH score and decrease of NRS pain score with an unrestricted hindfoot motion 1 year after surgery. Conclusion: 3D virtually planned bone cutting and wedge guides is a promising approach associated with minimal postoperative deviation from the desired correction in medial opening supramalleolar osteotomy

    Rest-Frame UV-Optical Selected Galaxies at 2.3 ≾ z ≾ 3.5: Searching for Dusty Star-forming and Passively Evolving Galaxies

    Get PDF
    A new set of color selection criteria (VJL) analogous with the BzK method is designed to select both star-forming galaxies (SFGs) and passively evolving galaxies (PEGs) at 2.3 ≾ z ≾ 3.5 by using rest-frame UV-optical (V – J versus J – L) colors. The criteria are thoroughly tested with theoretical stellar population synthesis models and real galaxies with spectroscopic redshifts to evaluate their efficiency and contamination. We apply the well-tested VJL criteria to the HST/WFC3 Early Release Science field and study the physical properties of selected galaxies. The redshift distribution of selected SFGs peaks at z ~ 2.7, slightly lower than that of Lyman break galaxies at z ~ 3. Comparing the observed mid-infrared fluxes of selected galaxies with the prediction of pure stellar emission, we find that our VJL method is effective at selecting massive dusty SFGs that are missed by the Lyman break technique. About half of the star formation in massive (M_(star) > 10^(10) M_☉) galaxies at 2.3 ≾ z ≾ 3.5 is contributed by dusty (extinction E(B – V) > 0.4) SFGs, which, however, only account for ~20% of the number density of massive SFGs. We also use the mid-infrared fluxes to clean our PEG sample and find that galaxy size can be used as a secondary criterion to effectively eliminate the contamination of dusty SFGs. The redshift distribution of the cleaned PEG sample peaks at z ~ 2.5. We find six PEG candidates at z > 3 and discuss possible methods to distinguish them from dusty contamination. We conclude that at least part of our candidates are real PEGs at z ~ 3, implying that these types of galaxies began to form their stars at z ≳ 5. We measure the integrated stellar mass density (ISMD) of PEGs at z ~ 2.5 and set constraints on it at z > 3. We find that the ISMD grows by at least about a factor of 10 in 1 Gyr at 3 < z <5 and by another factor of 10 in the next 3.5 Gyr (1 < z < 3)

    Structural Evolution of Early-type Galaxies to z=2.5 in CANDELS

    Get PDF
    Projected axis ratio measurements of 880 early-type galaxies at redshifts 1<z<2.5 selected from CANDELS are used to reconstruct and model their intrinsic shapes. The sample is selected on the basis of multiple rest-frame colors to reflect low star-formation activity. We demonstrate that these galaxies as an ensemble are dust-poor and transparent and therefore likely have smooth light profiles, similar to visually classified early-type galaxies. Similar to their present-day counterparts, the z>1 early-type galaxies show a variety of intrinsic shapes; even at a fixed mass, the projected axis ratio distributions cannot be explained by the random projection of a set of galaxies with very similar intrinsic shapes. However, a two-population model for the intrinsic shapes, consisting of a triaxial, fairly round population, combined with a flat (c/a~0.3) oblate population, adequately describes the projected axis ratio distributions of both present-day and z>1 early-type galaxies. We find that the proportion of oblate versus triaxial galaxies depends both on the galaxies' stellar mass, and - at a given mass - on redshift. For present-day and z<1 early-type galaxies the oblate fraction strongly depends on galaxy mass. At z>1 this trend is much weaker over the mass range explored here (10^10<M*/M_sun<10^11), because the oblate fraction among massive (M*~10^11 M_sun) was much higher in the past: 0.59+-0.10 at z>1, compared to 0.20+-0.02 at z~0.1. In contrast, the oblate fraction among low-mass early-type galaxies (log(M*/M_sun)1 to 0.72+-0.06 at z=0. [Abridged]Comment: accepted for publication in ApJ; 14 pages; 10 figures; 4 table

    CANDELS: The progenitors of compact quiescent galaxies at z~2

    Get PDF
    We combine high-resolution HST/WFC3 images with multi-wavelength photometry to track the evolution of structure and activity of massive (log(M*) > 10) galaxies at redshifts z = 1.4 - 3 in two fields of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). We detect compact, star-forming galaxies (cSFGs) whose number densities, masses, sizes, and star formation rates qualify them as likely progenitors of compact, quiescent, massive galaxies (cQGs) at z = 1.5 - 3. At z > 2 most cSFGs have specific star-formation rates (sSFR = 10^-9 yr^-1) half that of typical, massive SFGs at the same epoch, and host X-ray luminous AGN 30 times (~30%) more frequently. These properties suggest that cSFGs are formed by gas-rich processes (mergers or disk-instabilities) that induce a compact starburst and feed an AGN, which, in turn, quench the star formation on dynamical timescales (few 10^8 yr). The cSFGs are continuously being formed at z = 2 - 3 and fade to cQGs by z = 1.5. After this epoch, cSFGs are rare, thereby truncating the formation of new cQGs. Meanwhile, down to z = 1, existing cQGs continue to enlarge to match local QGs in size, while less-gas-rich mergers and other secular mechanisms shepherd (larger) SFGs as later arrivals to the red sequence. In summary, we propose two evolutionary scenarios of QG formation: an early (z > 2), fast-formation path of rapidly-quenched cSFGs that evolve into cQGs that later enlarge within the quiescent phase, and a slow, late-arrival (z < 2) path for SFGs to form QGs without passing through a compact state.Comment: Submitted to the Astrophysical Journal Letters, 6 pages, 4 figure

    The emission by dust and stars of nearby galaxies in the Herschel KINGFISH survey

    Get PDF
    Using new far-infrared imaging from the Herschel Space Observatory with ancillary data from ultraviolet (UV) to submillimeter wavelengths, we estimate the total emission from dust and stars of 62 nearby galaxies in the KINGFISH survey in a way that is as empirical and model independent as possible. We collect and exploit these data in order to measure from the spectral energy distributions (SEDs) precisely how much stellar radiation is intercepted and re-radiated by dust, and how this quantity varies with galaxy properties. By including SPIRE data, we are more sensitive to emission from cold dust grains than previous analyses at shorter wavelengths, allowing for more accurate estimates of dust temperatures and masses. The dust/stellar flux ratio, which we measure by integrating the SEDs, has a range of nearly three decades (from 10(-2.2) to 10(0.5)). The inclusion of SPIRE data shows that estimates based on data not reaching these far-IR wavelengths are biased low by 17% on average. We find that the dust/stellar flux ratio varies with morphology and total infrared (IR) luminosity, with dwarf galaxies having faint luminosities, spirals having relatively high dust/stellar ratios and IR luminosities, and some early types having low dust/stellar ratios. We also find that dust/stellar flux ratios are related to gas-phase metallicity ((log(f(dust)/f(*)) over bar) = -0.66 +/- 0.08 and -0.22 +/- 0.12 for metal-poor and intermediate-metallicity galaxies, respectively), while the dust/stellar mass ratios are less so (differing by approximate to 0.2 dex); the more metal-rich galaxies span a much wider range of the flux ratios. In addition, the substantial scatter between dust/stellar flux and dust/stellar mass indicates that the former is a poor proxy of the latter. Comparing the dust/stellar flux ratios and dust temperatures, we also show that early types tend to have slightly warmer temperatures (by up to 5 K) than spiral galaxies, which may be due to more intense interstellar radiation fields, or possibly to different dust grain compositions. Finally, we show that early types and early-type spirals have a strong correlation between the dust/stellar flux ratio and specific star formation rate, which suggests that the relatively bright far-IR emission of some of these galaxies is due to ongoing (if limited) star formation as well as to the radiation field from older stars, which is heating the dust grains

    CLASH-X: A Comparison of Lensing and X-ray Techniques for Measuring the Mass Profiles of Galaxy Clusters

    Get PDF
    We present profiles of temperature (Tx), gas mass, and hydrostatic mass estimated from new and archival X-ray observations of CLASH clusters. We compare measurements derived from XMM and Chandra observations with one another and compare both to gravitational lensing mass profiles derived with CLASH HST and ground-based lensing data. Radial profiles of Chandra and XMM electron density and enclosed gas mass are nearly identical, indicating that differences in hydrostatic masses inferred from X-ray observations arise from differences in Tx measurements. Encouragingly, cluster Txs are consistent with one another at ~100-200 kpc radii but XMM Tx systematically decline relative to Chandra Tx at larger radii. The angular dependence of the discrepancy suggests additional investigation on systematics such as the XMM point spread function correction, vignetting and off-axis responses. We present the CLASH-X mass-profile comparisons in the form of cosmology-independent and redshift-independent circular-velocity profiles. Ratios of Chandra HSE mass profiles to CLASH lensing profiles show no obvious radial dependence in the 0.3-0.8 Mpc range. However, the mean mass biases inferred from the WL and SaWLens data are different. e.g., the weighted-mean value at 0.5 Mpc is = 0.12 for the WL comparison and = -0.11 for the SaWLens comparison. The ratios of XMM HSE mass profiles to CLASH lensing profiles show a pronounced radial dependence in the 0.3-1.0 Mpc range, with a weighted mean mass bias of value rising to ~0.3 at ~1 Mpc for the WL comparison and of 0.25 for SaWLens comparison. The enclosed gas mass profiles from both Chandra and XMM rise to a value 1/8 times the total-mass profiles inferred from lensing at 0.5 Mpc and remain constant outside of that radius, suggesting that [8xMgas] profiles may be an excellent proxy for total-mass profiles at >0.5 Mpc in massive galaxy clusters.Comment: Accepted to ApJ; 24 pages; scheduled to appear in the Oct 10, 2014 issue. This version corrects the typographical error in the superscripts for Equation (2) to include the square of (r/r_core). The correct version of this equation was used in the analysi

    A CANDELS WFC3 Grism Study of Emission-Line Galaxies at z~2: A Mix of Nuclear Activity and Low-Metallicity Star Formation

    Full text link
    We present Hubble Space Telescope Wide Field Camera 3 slitless grism spectroscopy of 28 emission-line galaxies at z~2, in the GOODS-S region of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). The high sensitivity of these grism observations, with 1-sigma detections of emission lines to f > 2.5x10^{-18} erg/s/cm^2, means that the galaxies in the sample are typically ~7 times less massive (median M_* = 10^{9.5} M_sun) than previously studied z~2 emission-line galaxies. Despite their lower mass, the galaxies have OIII/Hb ratios which are very similar to previously studied z~2 galaxies and much higher than the typical emission-line ratios of local galaxies. The WFC3 grism allows for unique studies of spatial gradients in emission lines, and we stack the two-dimensional spectra of the galaxies for this purpose. In the stacked data the OIII emission line is more spatially concentrated than the Hb emission line with 98.1 confidence. We additionally stack the X-ray data (all sources are individually undetected), and find that the average L(OIII)/L(0.5-10 keV) ratio is intermediate between typical z~0 obscured active galaxies and star-forming galaxies. Together the compactness of the stacked OIII spatial profile and the stacked X-ray data suggest that at least some of these low-mass, low-metallicity galaxies harbor weak active galactic nuclei.Comment: ApJ accepted. 8 pages, 6 figure

    CANDELS Multi-wavelength Catalogs: Source Detection and Photometry in the GOODS-South Field

    Get PDF
    We present a UV-to-mid infrared multi-wavelength catalog in the CANDELS/GOODS-S field, combining the newly obtained CANDELS HST/WFC3 F105W, F125W, and F160W data with existing public data. The catalog is based on source detection in the WFC3 F160W band. The F160W mosaic includes the data from CANDELS deep and wide observations as well as previous ERS and HUDF09 programs. The mosaic reaches a 5σ\sigma limiting depth (within an aperture of radius 0.17 arcsec) of 27.4, 28.2, and 29.7 AB for CANDELS wide, deep, and HUDF regions, respectively. The catalog contains 34930 sources with the representative 50% completeness reaching 25.9, 26.6, and 28.1 AB in the F160W band for the three regions. In addition to WFC3 bands, the catalog also includes data from UV (U-band from both CTIO/MOSAIC and VLT/VIMOS), optical (HST/ACS F435W, F606W, F775W, F814W, and F850LP), and infrared (HST/WFC3 F098M, VLT/ISAAC Ks, VLT/HAWK-I Ks, and Spitzer/IRAC 3.6, 4.5, 5.8, 8.0 μ\mum) observations. The catalog is validated via stellar colors, comparison with other published catalogs, zeropoint offsets determined from the best-fit templates of the spectral energy distribution of spectroscopically observed objects, and the accuracy of photometric redshifts. The catalog is able to detect unreddened star-forming (passive) galaxies with stellar mass of 10^{10}M_\odot at a 50% completeness level to z\sim3.4 (2.8), 4.6 (3.2), and 7.0 (4.2) in the three regions. As an example of application, the catalog is used to select both star-forming and passive galaxies at z\sim2--4 via the Balmer break. It is also used to study the color--magnitude diagram of galaxies at 0<z<4.Comment: The full resolution article is now published in ApJS (2013, 207, 24). 22 pages, 21 figures, and 5 tables. The catalogue is available on the CANDELS website: http://candels.ucolick.org/data_access/GOODS-S.html MAST: http://archive.stsci.edu/prepds/candels and Rainbow Database: https://arcoiris.ucolick.org/Rainbow_navigator_public and https://rainbowx.fis.ucm.es/Rainbow_navigator_publi

    The Type Ia Supernova Rate in Redshift 0.5--0.9 Galaxy Clusters

    Get PDF
    Supernova (SN) rates are potentially powerful diagnostics of metal enrichment and SN physics, particularly in galaxy clusters with their deep, metal-retaining potentials and relatively simple star-formation histories. We have carried out a survey for supernovae (SNe) in galaxy clusters, at a redshift range 0.5<z<0.9, using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. We reimaged a sample of 15 clusters that were previously imaged by ACS, thus obtaining two to three epochs per cluster, in which we discovered five likely cluster SNe, six possible cluster SNe Ia, two hostless SN candidates, and several background and foreground events. Keck spectra of the host galaxies were obtained to establish cluster membership. We conducted detailed efficiency simulations, and measured the stellar luminosities of the clusters using Subaru images. We derive a cluster SN rate of 0.35 SNuB +0.17/-0.12 (statistical) \pm0.13 (classification) \pm0.01 (systematic) [where SNuB = SNe (100 yr 10^10 L_B_sun)^-1] and 0.112 SNuM +0.055/-0.039 (statistical) \pm0.042 (classification) \pm0.005 (systematic) [where SNuM = SNe (100 yr 10^10 M_sun)^-1]. As in previous measurements of cluster SN rates, the uncertainties are dominated by small-number statistics. The SN rate in this redshift bin is consistent with the SN rate in clusters at lower redshifts (to within the uncertainties), and shows that there is, at most, only a slight increase of cluster SN rate with increasing redshift. The low and fairly constant SN Ia rate out to z~1 implies that the bulk of the iron mass in clusters was already in place by z~1. The recently observed doubling of iron abundances in the intracluster medium between z=1 and 0, if real, is likely the result of redistribution of existing iron, rather than new production of iron.Comment: Accepted to ApJ. Full resolution version available at http://kicp.uchicago.edu/~kerens/HSTclusterSNe

    Maturing Human CD127+ CCR7+ PDL1+ Dendritic Cells Express AIRE in the Absence of Tissue Restricted Antigens.

    Get PDF
    Expression of the Autoimmune regulator (AIRE) outside of the thymus has long been suggested in both humans and mice, but the cellular source in humans has remained undefined. Here we identify AIRE expression in human tonsils and extensively analyzed these "extra-thymic AIRE expressing cells" (eTACs) using combinations of flow cytometry, CyTOF and single cell RNA-sequencing. We identified AIRE+ cells as dendritic cells (DCs) with a mature and migratory phenotype including high levels of antigen presenting molecules and costimulatory molecules, and specific expression of CD127, CCR7, and PDL1. These cells also possessed the ability to stimulate and re-stimulate T cells and displayed reduced responses to toll-like receptor (TLR) agonists compared to conventional DCs. While expression of AIRE was enriched within CCR7+CD127+ DCs, single-cell RNA sequencing revealed expression of AIRE to be transient, rather than stable, and associated with the differentiation to a mature phenotype. The role of AIRE in central tolerance induction within the thymus is well-established, however our study shows that AIRE expression within the periphery is not associated with an enriched expression of tissue-restricted antigens (TRAs). This unexpected finding, suggestive of wider functions of AIRE, may provide an explanation for the non-autoimmune symptoms of APECED patients who lack functional AIRE.JF and HS were funded by project ERC-2013-ADG number 341038. MB was funded by EMBO ALTF 786-2013. BH was supported by the Netherlands Organization for Scientific Research (NWO) Veni program (91618032). LH, JpvH, and ST were supported by a grant from the Dutch Arthritis Foundation (2013_2_37). MM was supported by Wellcome Trust (grant105045/Z/14/Z). JM was supported by core funding from the European Molecular Biology Laboratory and from Cancer Research UK (award number 17197)
    corecore