ABSTRACT We search for excess γ-ray emission coincident with the positions of confirmed and candidate Milky Way satellite galaxies using six years of data from the Fermi Large Area Telescope (LAT). ...Our sample of 45 stellar systems includes 28 kinematically confirmed dark-matter-dominated dwarf spheroidal galaxies (dSphs) and 17 recently discovered systems that have photometric characteristics consistent with the population of known dSphs. For each of these targets, the relative predicted γ-ray flux due to dark matter annihilation is taken from kinematic analysis if available, and estimated from a distance-based scaling relation otherwise, assuming that the stellar systems are DM-dominated dSphs. LAT data coincident with four of the newly discovered targets show a slight preference (each 2 local) for γ-ray emission in excess of the background. However, the ensemble of derived γ-ray flux upper limits for individual targets is consistent with the expectation from analyzing random blank-sky regions, and a combined analysis of the population of stellar systems yields no globally significant excess (global significance ). Our analysis has increased sensitivity compared to the analysis of 15 confirmed dSphs by Ackermann et al. The observed constraints on the DM annihilation cross section are statistically consistent with the background expectation, improving by a factor of ∼2 for large DM masses ( and ) and weakening by a factor of ∼1.5 at lower masses relative to previously observed limits.
— Aims and Methods: Alcohol withdrawal treatment efficacy of tiapride/carbamazepine (A) vs clomethiazole (B) vs diazepam (C) in non-intoxicated patients and vs tiapride/carbamazepine in intoxicated ...patients (D; breath alcohol concentration ≥ 1 g/l) was tested (n = 127) in a controlled randomized open-label study. Results: Efficacy and safety were not different between groups (total group: delirium, 3.9%; seizure, 0.8%), except for a lack of efficacy in 18% of intoxicated tiapride/carbamazepine patients. A change of medication in this group was necessary only when primarily intoxicated patients had reached the non-intoxicated range. Conclusions: Treatment with tiapride/carbamazepine in alcohol-intoxicated patients proved to be safe.
ABSTRACT
We present an improved measurement of the Hubble constant (H0) using the ‘inverse distance ladder’ method, which adds the information from 207 Type Ia supernovae (SNe Ia) from the Dark ...Energy Survey (DES) at redshift 0.018 < z < 0.85 to existing distance measurements of 122 low-redshift (z < 0.07) SNe Ia (Low-z) and measurements of Baryon Acoustic Oscillations (BAOs). Whereas traditional measurements of H0 with SNe Ia use a distance ladder of parallax and Cepheid variable stars, the inverse distance ladder relies on absolute distance measurements from the BAOs to calibrate the intrinsic magnitude of the SNe Ia. We find H0 = 67.8 ± 1.3 km s−1 Mpc−1 (statistical and systematic uncertainties, 68 per cent confidence). Our measurement makes minimal assumptions about the underlying cosmological model, and our analysis was blinded to reduce confirmation bias. We examine possible systematic uncertainties and all are below the statistical uncertainties. Our H0 value is consistent with estimates derived from the Cosmic Microwave Background assuming a ΛCDM universe.
We perform a search for stellar streams around the Milky Way using the first 3 yr of multiband optical imaging data from the Dark Energy Survey (DES). We use DES data covering ∼5000 deg2 to a depth ...of g > 23.5 with a relative photometric calibration uncertainty of <1%. This data set yields unprecedented sensitivity to the stellar density field in the southern celestial hemisphere, enabling the detection of faint stellar streams to a heliocentric distance of ∼50 kpc. We search for stellar streams using a matched filter in color-magnitude space derived from a synthetic isochrone of an old, metal-poor stellar population. Our detection technique recovers four previously known thin stellar streams: Phoenix, ATLAS, Tucana III, and a possible extension of Molonglo. In addition, we report the discovery of 11 new stellar streams. In general, the new streams detected by DES are fainter, more distant, and lower surface brightness than streams detected by similar techniques in previous photometric surveys. As a by-product of our stellar stream search, we find evidence for extratidal stellar structure associated with four globular clusters: NGC 288, NGC 1261, NGC 1851, and NGC 1904. The ever-growing sample of stellar streams will provide insight into the formation of the Galactic stellar halo, the Milky Way gravitational potential, and the large- and small-scale distribution of dark matter around the Milky Way.
The population of Milky Way (MW) satellites contains the faintest known galaxies and thus provides essential insight into galaxy formation and dark matter microphysics. Here we combine a model of the ...galaxy-halo connection with newly derived observational selection functions based on searches for satellites in photometric surveys over nearly the entire high Galactic latitude sky. In particular, we use cosmological zoom-in simulations of MW-like halos that include realistic Large Magellanic Cloud (LMC) analogs to fit the position-dependent MW satellite luminosity function. We report decisive evidence for the statistical impact of the LMC on the MW satellite population due to an estimated 6 2 observed LMC-associated satellites, consistent with the number of LMC satellites inferred from Gaia proper-motion measurements, confirming the predictions of cold dark matter models for the existence of satellites within satellite halos. Moreover, we infer that the LMC fell into the MW within the last 2 Gyr at high confidence. Based on our detailed full-sky modeling, we find that the faintest observed satellites inhabit halos with peak virial masses below at 95% confidence, and we place the first robust constraints on the fraction of halos that host galaxies in this regime. We predict that the faintest detectable satellites occupy halos with peak virial masses above , highlighting the potential for powerful galaxy formation and dark matter constraints from future dwarf galaxy searches.
ABSTRACT
We present angular diameter distance measurements obtained by locating the baryon acoustic oscillations (BAO) scale in the distribution of galaxies selected from the first year of Dark ...Energy Survey data. We consider a sample of over 1.3 million galaxies distributed over a footprint of 1336 deg2 with 0.6 < $z$photo < 1 and a typical redshift uncertainty of 0.03(1 + $z$). This sample was selected, as fully described in a companion paper, using a colour/magnitude selection that optimizes trade-offs between number density and redshift uncertainty. We investigate the BAO signal in the projected clustering using three conventions, the angular separation, the comoving transverse separation, and spherical harmonics. Further, we compare results obtained from template-based and machine-learning photometric redshift determinations. We use 1800 simulations that approximate our sample in order to produce covariance matrices and allow us to validate our distance scale measurement methodology. We measure the angular diameter distance, DA, at the effective redshift of our sample divided by the true physical scale of the BAO feature, rd. We obtain close to a 4 per cent distance measurement of DA($z$eff = 0.81)/rd = 10.75 ± 0.43. These results are consistent with the flat Λ cold dark matter concordance cosmological model supported by numerous other recent experimental results.
ABSTRACT We describe updates to the redMaPPer algorithm, a photometric red-sequence cluster finder specifically designed for large photometric surveys. The updated algorithm is applied to of Science ...Verification (SV) data from the Dark Energy Survey (DES), and to the Sloan Digital Sky Survey (SDSS) DR8 photometric data set. The DES SV catalog is locally volume limited and contains 786 clusters with richness (roughly equivalent to ) and . The DR8 catalog consists of 26,311 clusters with , with a sharply increasing richness threshold as a function of redshift for . The photometric redshift performance of both catalogs is shown to be excellent, with photometric redshift uncertainties controlled at the level for , rising to ∼0.02 at in DES SV. We make use of Chandra and XMM X-ray and South Pole Telescope Sunyaev-Zeldovich data to show that the centering performance and mass-richness scatter are consistent with expectations based on prior runs of redMaPPer on SDSS data. We also show how the redMaPPer photo-z and richness estimates are relatively insensitive to imperfect star/galaxy separation and small-scale star masks.
Widespread degradation and destruction of coastal wetlands over the last century have spurred on the practice of creating salt marshes to mitigate losses of wetland area and ecosystem function. ...Constructed marshes can quickly recover plant biomass, but biogeochemical functions, such as nitrogen removal capacity through denitrification, can take decades to centuries to recover. One potential mechanism for this uncoupling of structural and functional recovery is that an impaired microbial community subsequently impedes the nitrogen removal capacity of constructed marshes. While both bacteria and fungi can contribute to nitrogen removal via denitrification, little is known about fungal denitrification in wetlands, even though it has the potential to contribute to climate change via the production of the greenhouse gas nitrous oxide. Here, we measured fungal and bacterial denitrification potential rates and fungal biomass in sediments collected from a 33-year-old constructed marsh and a reference natural marsh to assess both a) the relative contribution of each group to total nitrogen removal and b) whether fungal biomass accrual is a driver of functional recovery in salt marshes. To assess the relative contributions of fungi and bacteria to denitrification, we added selective inhibitors (antifungal, antibacterial, or both) to sediments from each marsh and measured potential fungal and bacterial denitrification rates. We also measured sediment ergosterol concentrations seasonally as a proxy for fungal biomass. In the absence of inhibitors, denitrification potential rates in the constructed marsh were three times lower than in natural marsh sediment. Further, denitrification rates in the constructed marsh remained similarly low regardless of increasing inhibitor concentration, whereas denitrification rates in the natural marsh declined with increasing inhibitor concentration. When either inhibitor was added alone, denitrification was stimulated in the natural marsh, but was suppressed in the constructed marsh, suggesting an apparent competitive release, where the reduction of either bacterial or fungal competition for substrate thereby allowed the remaining competitor greater access to the substrate, in the natural marsh. We observed that compared to the constructed marsh, fungi in the natural marsh contributed ∼30% more (50% vs. 21%) to denitrification, and that fungal biomass was generally higher. Collectively, these data suggest that 3 decades post construction, denitrification rates and the contribution of fungal denitrification to total denitrification are lower in the constructed marsh than the natural marsh. These data also suggest that fungal biomass may limit the recovery of nitrogen removal in constructed marshes and that fungal denitrification can be an important pathway of N removal in salt marsh ecosystems.
•Fungi contribute as much as 50% of denitrification in natural salt marshes.•Constructed marshes have lower fungal biomass and denitrification rates.•Bacteria and fungi compete for nitrogen in salt marsh sediments.•Constructed marsh microbial biomass recovery may limit biogeochemical recovery.
We report the results of a systematic search for ultra-faint Milky Way satellite galaxies using data from the Dark Energy Survey (DES) and Pan-STARRS1 (PS1). Together, DES and PS1 provide multi-band ...photometry in optical/near-infrared wavelengths over ∼80% of the sky. Our search for satellite galaxies targets ∼25,000 deg2 of the high-Galactic-latitude sky reaching a 10 point-source depth of 22.5 mag in the g and r bands. While satellite galaxy searches have been performed independently on DES and PS1 before, this is the first time that a self-consistent search is performed across both data sets. We do not detect any new high-significance satellite galaxy candidates, recovering the majority of satellites previously detected in surveys of comparable depth. We characterize the sensitivity of our search using a large set of simulated satellites injected into the survey data. We use these simulations to derive both analytic and machine-learning models that accurately predict the detectability of Milky Way satellites as a function of their distance, size, luminosity, and location on the sky. To demonstrate the utility of this observational selection function, we calculate the luminosity function of Milky Way satellite galaxies, assuming that the known population of satellite galaxies is representative of the underlying distribution. We provide access to our observational selection function to facilitate comparisons with cosmological models of galaxy formation and evolution.
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