527 research outputs found

    Accurate Modeling of Weak Lensing with the sGL Method

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    We revise and extend the stochastic approach to cumulative weak lensing (hereafter the sGL method) first introduced in Ref. [1]. Here we include a realistic halo mass function and density profiles to model the distribution of mass between and within galaxies, galaxy groups and galaxy clusters. We also introduce a modeling of the filamentary large-scale structures and a method to embed halos into these structures. We show that the sGL method naturally reproduces the weak lensing results for the Millennium Simulation. The strength of the sGL method is that a numerical code based on it can compute the lensing probability distribution function for a given inhomogeneous model universe in a few seconds. This makes it a useful tool to study how lensing depends on cosmological parameters and its impact on observations. The method can also be used to simulate the effect of a wide array of systematic biases on the observable PDF. As an example we show how simple selection effects may reduce the variance of observed PDF, which could possibly mask opposite effects from very large scale structures. We also show how a JDEM-like survey could constrain the lensing PDF relative to a given cosmological model. The updated turboGL code is available at turboGL.org.Comment: PRD style: 20 pages, 10 figures; replaced to match the improved version accepted for publication in PRD. The updated turboGL code can be downloaded at http://www.turbogl.org

    The stellar content of the infalling molecular clump G286.21+0.17

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    The early evolution during massive star cluster formation is still uncertain. Observing embedded clusters at their earliest stages of formation can provide insight into the spatial and temporal distribution of the stars and thus probe different star cluster formation models. We present near-infrared imaging of an 8'*13'(5.4pc*8.7pc) region around the massive infalling clump G286.21+0.17(also known as BYF73). The stellar content across the field is determined and photometry is derived in order to { obtain} stellar parameters for the cluster members. We find evidence for some sub-structure (on scales less than a pc diameter) within the region with apparently at least three different sub-clusters associated with the molecular clump based on differences in extinction and disk fractions. At the center of the clump we identify a deeply embedded sub-cluster. Near-infrared excess is detected for 39-44% in the two sub-clusters associated with molecular material and 27% for the exposed cluster. Using the disk excess as a proxy for age this suggests the clusters are very young. The current total stellar mass is estimated to be at least 200 Msun. The molecular core hosts a rich population of pre-main sequence stars. There is evidence for multiple events of star formation both in terms of the spatial distribution within the star forming region and possibly from the disk frequency.Comment: Submitted to A

    Chaos, Determinacy and Fractals in Active-Sterile Neutrino Oscillations in the Early Universe

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    The possibility of light sterile neutrinos allows for the resonant production of lepton number in the early universe through matter-affected neutrino mixing. For a given a mixing of the active and sterile neutrino states it has been found that the lepton number generation process is chaotic and strongly oscillatory. We undertake a new study of this process' sensitivity to initial conditions through the quantum rate equations. We confirm the chaoticity of the process in this solution, and moreover find that the resultant lepton number and the sign of the asymmetry produces a fractal in the parameter space of mass, mixing angle and initial baryon number. This has implications for future searches for sterile neutrinos, where arbitrary high sensitivity could not be determinate in forecasting the lepton number of the universe.Comment: 6 pages, 3 figure

    Superweakly interacting dark matter from the Minimal Walking Technicolor

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    We study a superweakly interacting dark matter particle motivated by minimal walking technicolor theories. Our WIMP is a mixture of a sterile state and a state with the charges of a standard model fourth family neutrino. We show that the model can give the right amount of dark matter over a range of the WIMP mass and mixing angle. We compute bounds on the model parameters from the current accelerator data including the oblique corrections to the precision electroweak parameters, as well as from cryogenic experiments, Super-Kamiokande and from the IceCube experiment. We show that consistent dark matter solutions exist which satisfy all current constraints. However, almost the entire parameter range of the model lies within the the combined reach of the next generation experiments.Comment: 29 pages, 6 figure

    Gas Kinematics and Excitation in the Filamentary IRDC G035.39-00.33

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    Some theories of dense molecular cloud formation involve dynamical environments driven by converging atomic flows or collisions between preexisting molecular clouds. The determination of the dynamics and physical conditions of the gas in clouds at the early stages of their evolution is essential to establish the dynamical imprints of such collisions, and to infer the processes involved in their formation. We present multi-transition 13CO and C18O maps toward the IRDC G035.39-00.33, believed to be at the earliest stages of evolution. The 13CO and C18O gas is distributed in three filaments (Filaments 1, 2 and 3), where the most massive cores are preferentially found at the intersecting regions between them. The filaments have a similar kinematic structure with smooth velocity gradients of ~0.4-0.8 km s-1 pc-1. Several scenarios are proposed to explain these gradients, including cloud rotation, gas accretion along the filaments, global gravitational collapse, and unresolved sub-filament structures. These results are complemented by HCO+, HNC, H13CO+ and HN13C single-pointing data to search for gas infall signatures. The 13CO and C18O gas motions are supersonic across G035.39-00.33, with the emission showing broader linewidths toward the edges of the IRDC. This could be due to energy dissipation at the densest regions in the cloud. The average H2 densities are ~5000-7000 cm-3, with Filaments 2 and 3 being denser and more massive than Filament 1. The C18O data unveils three regions with high CO depletion factors (f_D~5-12), similar to those found in massive starless cores.Comment: 20 pages, 14 figures, 6 tables, accepted for publication in MNRA

    Higgs Phenomenology with CPsuperH

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    The MSSM contains CP-violating phases that may have important observable effects in Higgs physics. We review recent highlights in Higgs phenomenology obtained with the code CPsuperH, a useful tool for studies of the production, mixing and decay of a coupled system of the neutral Higgs bosons at future high energy colliders such as the LHC, ILC (Îł\gammaLC), and a muon collider (MC). CPsuperH implements the constraints from upper limits on electric dipole moments, and may be extended to include other related low-energy observables, such as b -> s \gamma and B -> K l l, and to compute the relic abundance of the lightest neutralino.Comment: 20 pages, LaTeX, 7 figures, invited article by Modern Physics Letters A (review section

    Modeling of weak lensing statistics. II. Configuration-space statistics

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    We investigate the performance of an analytic model of the 3D matter distribution, which combines perturbation theory with halo models, for weak-lensing configuration-space statistics. We compared our predictions for the weak-lensing convergence two-point and three-point correlation functions with numerical simulations and fitting formulas proposed in previous works. We also considered the second- and third-order moments of the smoothed convergence and of the aperture-mass. As in our previous study of Fourier-space weak-lensing statistics, we find that our model agrees better with simulations than previously published fitting formulas. Moreover, we recover the dependence on cosmology of these weak-lensing statistics and we can describe multi-scale moments. This approach allows us to obtain the quantitative relationship between these integrated weak-lensing statistics and the various contributions to the underlying 3D density fluctuations, decomposed over perturbative, two-halo, or one-halo terms.Comment: 11 page

    Long-term quality of life after surgery of head and neck cancer with microvascular reconstruction : a prospective study with 4.9-years follow-up

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    Purpose The aim of this study was to evaluate the long-term health-related quality of life (HRQoL) of head and neck cancer patients with microvascular surgery. Surgical treatment causes great changes in patient HRQoL. Studies focusing on long-term HRQoL after microvascular reconstruction for head and neck cancer patients are scarce. Methods We conducted a prospective study of 93 patients with head and neck cancer and microvascular reconstruction in Helsinki University Hospital Finland. HRQoL was measured using the 15D instrument at baseline and after a mean 4.9-years follow up. Results were compared with those of an age-standardized general population. Results Of the 93 patients, 61 (66%) were alive after follow-up; of these, 42 (69%) answered the follow-up questionnaire. The median time between surgery and HRQoL assessment was 4.9 years (range 3.7-7.8 years). The mean 15D score of all patients (n = 42) at the 4.9-years follow up was statistically significantly (p = 0.010) and clinically importantly lower than at baseline. The dimensions of "speech" and "usual activities" were significantly impaired at the end of follow up. There was a significant difference at the 4.9-years follow-up in the mean 15D score between patients and the general population (p = 0.014). After follow up, patients were significantly (p <0.05) worse off on the dimensions of "speech," "eating," and "usual activities." Conclusions Long-term HRQoL was significantly reduced in the whole patient cohort. Speech and usual activities were the most affected dimensions in head and neck cancer patients with microvascular reconstruction at the end of the 4.9-years follow up.Peer reviewe
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