On a functional satisfying a weak Palais-Smale condition

In this paper we study a quasilinear elliptic problem whose functional satisfies a weak version of the well known Palais-Smale condition. An existence result is proved under general assumptions on the nonlinearities.Comment: 18 page

Disk galaxies with broken luminosity profiles from cosmological simulations

We present SPH cosmological simulations of the formation of three disk galaxies with a detailed treatment of chemical evolution and cooling. The resulting galaxies have properties compatible with observations: relatively high disk-to-total ratios, thin stellar disks and good agreement with the Tully-Fisher and the luminosity-size relations. They present a break in the luminosity profile at 3.0 +- 0.5 disk scale lengths, while showing an exponential mass profile without any apparent breaks, in line with recent observational results. Since the stellar mass profile is exponential, only differences in the stellar populations can be the cause of the luminosity break. Although we find a cutoff for the star formation rate imposed by a density threshold in our star formation model, it does not coincide with the luminosity break and is located at 4.3 +- 0.4 disk scale lengths, with star formation going on between both radii. The color profiles and the age profiles are "U-shaped", with the minimum for both profiles located approximately at the break radius. The SFR to stellar mass ratio increases until the break, explaining the coincidence of the break with the minimum of the age profile. Beyond the break we find a steep decline in the gas density and, consequently, a decline in the SFR and redder colors. We show that most stars (64-78%) in the outer disk originate in the inner disk and afterwards migrate there. Such stellar migrations are likely the main origin of the U-shaped age profile and, therefore, of the luminosity break.Comment: 8 pages, 4 figures. Accepted by ApJ

Wavelength calibration of the JWST-MIRI medium resolution spectrometer

We present the wavelength and spectral resolution characterisation of the Integral Field Unit (IFU) Medium Resolution Spectrometer for the Mid-InfraRed Instrument (MIRI), to fly onboard the James Webb Space Telescope in 2014. We use data collected using the Verification Model of the instrument and develop an empirical method to calibrate properties such as wavelength range and resolving power in a portion of the spectrometer's full spectral range (5-28 microns). We test our results against optical models to verify the system requirements and combine them with a study of the fringing pattern in the instrument's detector to provide a more accurate calibration. We show that MIRI's IFU spectrometer will be able to produce spectra with a resolving power above R=2800 in the wavelength range 6.46-7.70 microns, and that the unresolved spectral lines are well fitted by a Gaussian profile.Comment: 12 pages, submitted to SPIE Proceedings vol. 7731, Space Telescopes and Instrumentation 2010: Optical, Infrared, and Millimeter Wav

Cosmic Evolution of Stellar Disk Truncations: From z~1 to the Local Universe

We have conducted the largest systematic search so far for stellar disk truncations in disk-like galaxies at intermediate redshift (z<1.1), using the Great Observatories Origins Deep Survey South (GOODS-S) data from the Hubble Space Telescope - ACS. Focusing on Type II galaxies (i.e. downbending profiles) we explore whether the position of the break in the rest-frame B-band radial surface brightness profile (a direct estimator of the extent of the disk where most of the massive star formation is taking place), evolves with time. The number of galaxies under analysis (238 of a total of 505) is an order of magnitude larger than in previous studies. For the first time, we probe the evolution of the break radius for a given stellar mass (a parameter well suited to address evolutionary studies). Our results suggest that, for a given stellar mass, the radial position of the break has increased with cosmic time by a factor 1.3+/-0.1 between z~1 and z~0. This is in agreement with a moderate inside-out growth of the disk galaxies in the last ~8 Gyr. In the same period of time, the surface brightness level in the rest-frame B-band at which the break takes place has increased by 3.3+/-0.2 mag/arcsec^2 (a decrease in brightness by a factor of 20.9+/-4.2). We have explored the distribution of the scale lengths of the disks in the region inside the break, and how this parameter relates to the break radius. We also present results of the statistical analysis of profiles of artificial galaxies, to assess the reliability of our results.Comment: 22 pages, 14 figures, accepted for publication in ApJ. Figures 1, 3 and 6 have somehow downgraded resolution to match uploading requirement

Analysis of BRCA1 and RAD51C promoter methylation in italian families at high-risk of breast and ovarian cancer

Previous studies on breast and ovarian carcinoma (BC and OC) revealed constitutional BRCA1 and RAD51C promoter hypermethylation as epigenetic alterations leading to tumor predisposition. Nevertheless, the impact of epimutations at these genes is still debated. One hundred and eight women affected by BC, OC, or both and considered at very high risk of carrying BRCA1 germline mutations were studied. All samples were negative for pathogenic variants or variants of uncertain significance at BRCA testing. Quantitative BRCA1 and RAD51C promoter methylation analyses were performed by Epityper mass spectrometry on peripheral blood samples and results were compared with those in controls. All the 108 analyzed cases showed methylation levels at the BRCA1/RAD51C promoter comparable with controls. Mean methylation levels (\ub1 stdev) at the BRCA1 promoter were 4.3% (\ub1 1.4%) and 4.4% (\ub1 1.4%) in controls and patients, respectively (p &gt; 0.05; t-test); mean methylation levels (\ub1 stdev) at the RAD51C promoter were 4.3% (\ub1 0.9%) and 3.7% (\ub1 0.9%) in controls and patients, respectively (p &gt; 0.05; t-test). Based on these observations; the analysis of constitutional methylation at promoters of these genes does not seem to substantially improve the definition of cancer risks in patients. These data support the idea that epimutations represent a very rare event in high-risk BC/OC populations

Nonlinear Klein-Gordon-Maxwell systems with Neumann boundary conditions on a Riemannian manifold with boundary

Let (M,g) be a smooth compact, n dimensional Riemannian manifold, n=3,4 with smooth n-1 dimensional boundary. We search the positive solutions of the singularly perturbed Klein Gordon Maxwell Proca system with homogeneous Neumann boundary conditions or for the singularly perturbed Klein Gordon Maxwell system with mixed Dirichlet Neumann homogeneous boundary conditions. We prove that stable critical points of the mean curvature of the boundary generates solutions when the perturbation parameter is sufficiently small.Comment: arXiv admin note: text overlap with arXiv:1410.884

Radial Distribution of Near-UV Flux in Disc Galaxies in the range 0<z<1

(Abridged) The goal of this paper is to quantify the changes on the SF distribution within the disc galaxies in the last ~8 Gyr. We use as a proxy for the SF radial profile the Near-UV surface brightness distributions, allowing suitably for extinction. We compare the effective radii (R_eff) and concentration of the flux distribution in the rest-frame Near-UV for a sample of 270 galaxies in the range 0<z<1. This radial distribution is compared to that measured in the rest-frame B-band, which traces older stellar populations. The analysis is performed using deep, high resolution, multi-band images from GALEX, SDSS, and HST/ACS - GOODS-South. The relation R_eff(NUV)- M* suffers a moderate change between z~1 and z~0: at a fixed stellar mass of 1E10 M_sun, galaxies increase their effective radii by a factor 1.18+/-0.06. Median profiles in NUV show signs of truncation at R~R_eff, and median colour profiles (NUV-B) show a minimum (a "bluest" point) also around R~1-1.5 R_eff. The distributions of NUV flux are more compact at z~1 than nowadays, in terms of the fraction of flux enclosed in a specific radius (in kpc). Our results indicate that the SF surface density has decreased dramatically in discs since z~1, and this decline has been more intense in the central parts (<~R_eff) of the galaxies. In addition, our data suggest that the bulges/pseudo-bulges have grown in surface brightness with regard to the discs since z~1.Comment: 26 pages, 21 figures, accepted for publication in Astronomy & Astrophysics on March 21s

The kinematics of water masers in the stellar molecular outflow source IRAS 19134+2131

Using the Very Large Array (VLA) and the Very Long Baseline Array (VLBA), we have observed water maser emission in the proto-planetary nebula candidate IRAS 19134+2131, in which the water maser spectrum has two groups of emission features separated in radial velocity by ∼100 km s^−1. The blue-shifted and red-shifted clusters of maser features are clearly separated spatially by ∼150 mas, indicative of a fast collimated flow. However, not all of the maser features are aligned along the axis of the flow, as is seen in the similar high-velocity water maser source, W43A. Comparing the VLA and VLBA maps of the water maser source, we find 4 maser features that were active for 2 years. Using only VLBA data, we identified proper motions for 8 maser features. The full 3D outflow velocity is estimated to be ∼130 km s^−1, indicating that the dynamical age of the flow is only ∼50 yr. On the basis of the relative positions with respect to the nearby extragalactic reference source, J1925+2106, we also obtain a secular motion of IRAS 19134+2131 of μl = −4.6 ± 0.7 mas yr^−1 along the Galactic plane toward the Galactic centre. This indicates a “far distance” (≥16 kpc) for IRAS 19134+2131 if the Galactic rotation curve remains flat at 220 km s^−1.Hachisuka, Kazuya, [email protected]