Radio Weak Gravitational Lensing with VLA and MERLIN

We carry out an exploratory weak gravitational lensing analysis on a combined VLA and MERLIN radio data set: a deep (3.3 micro-Jy beam^-1 rms noise) 1.4 GHz image of the Hubble Deep Field North. We measure the shear estimator distribution at this radio sensitivity for the first time, finding a similar distribution to that of optical shear estimators for HST ACS data in this field. We examine the residual systematics in shear estimation for the radio data, and give cosmological constraints from radio-optical shear cross-correlation functions. We emphasize the utility of cross-correlating shear estimators from radio and optical data in order to reduce the impact of systematics. Unexpectedly we find no evidence of correlation between optical and radio intrinsic ellipticities of matched objects; this result improves the properties of optical-radio lensing cross-correlations. We explore the ellipticity distribution of the radio counterparts to optical sources statistically, confirming the lack of correlation; as a result we suggest a connected statistical approach to radio shear measurements.Comment: 16 pages with 19 figures, accepted for publication in MNRAS; Minor corrections to section 6.3; 2 references adde

Complete characterization of sink-strengths for 1D to 3D mobilities of defect clusters.II. Bridging between limiting cases with effective sink-strengths calculations

In a companion paper, we proposed new analytical expressions of cluster sink-strengths (CSS) indispensable to any complete parameterization of rate equations cluster dynamics accounting for reaction between defect clusters populations having a 1D-mobility. In this second paper, we first establish simulation setup rules for truly converged estimates of effective CSS by Kinetic Monte-Carlo, and then we grid on a wide set of radii, rotation energies, diffusion coefficients and concentrations of both reaction partners. Symmetric roles of some parameters are used to infer a generic form for a semi-analytical expression of CSS depending on all these interaction parameters: it is composed of the various analytical limiting cases established and fitted transition functions that allow a gradual switching between them. The analysis of the residuals shows that the overall agreement is reasonably good: it is only in the transition zones that discrepancies are located and this is due to the asymmetry of the actual transition functions. The expression can be easily extended to temperatures at least a few hundred degrees around the reference. But further extending the CSS evaluations to much smaller diffusion coefficients ratios, we see that the domain for 1D-1D mobility is very extended: for a $10^{-3}$ ratio the computed CSS is still not correctly described by the 1D-CSS with respect to a fixed sink (1D-0), but rather by the established 1D-1D expression. For our typical sets of conditions, it is only when approaching a ratio of $10^{-6}$ that the 1D-0 CSS starts to become more relevant. This highlights the counter-intuitive fact that the growth kinetics of moderately trapped 1D mobile loops, whose effective mobility is greatly reduced, may not be described by 1D-0 kinetics but rather by appropriately corrected 1D-1D CSS which have completely different order of magnitude and kinetic orders.Comment: 21 pages, 12 figure

Sparse Bayesian mass-mapping with uncertainties: hypothesis testing of structure

A crucial aspect of mass-mapping, via weak lensing, is quantification of the uncertainty introduced during the reconstruction process. Properly accounting for these errors has been largely ignored to date. We present results from a new method that reconstructs maximum a posteriori (MAP) convergence maps by formulating an unconstrained Bayesian inference problem with Laplace-type $\ell_1$-norm sparsity-promoting priors, which we solve via convex optimization. Approaching mass-mapping in this manner allows us to exploit recent developments in probability concentration theory to infer theoretically conservative uncertainties for our MAP reconstructions, without relying on assumptions of Gaussianity. For the first time these methods allow us to perform hypothesis testing of structure, from which it is possible to distinguish between physical objects and artifacts of the reconstruction. Here we present this new formalism, demonstrate the method on illustrative examples, before applying the developed formalism to two observational datasets of the Abel-520 cluster. In our Bayesian framework it is found that neither Abel-520 dataset can conclusively determine the physicality of individual local massive substructure at significant confidence. However, in both cases the recovered MAP estimators are consistent with both sets of data

Type Ia Supernova Light Curves

The diversity of Type Ia supernova (SN Ia) photometry is explored using a grid of 130 one-dimensional models. It is shown that the observable properties of SNe Ia resulting from Chandrasekhar-mass explosions are chiefly determined by their final composition and some measure of ``mixing'' in the explosion. A grid of final compositions is explored including essentially all combinations of 56Ni, stable ``iron'', and intermediate mass elements that result in an unbound white dwarf. Light curves (and in some cases spectra) are calculated for each model using two different approaches to the radiation transport problem. Within the resulting templates are models that provide good photometric matches to essentially the entire range of observed SNe Ia. On the whole, the grid of models spans a wide range in B-band peak magnitudes and decline rates, and does not obey a Phillips relation. In particular, models with the same mass of 56Ni show large variations in their light curve decline rates. We identify the physical parameters responsible for this dispersion, and consider physically motivated ``cuts'' of the models that agree better with the Phillips relation. For example, models that produce a constant total mass of burned material of 1.1 +/- Msun do give a crude Phillips relation, albeit with much scatter. The scatter is further reduced if one restricts that set to models that make 0.1 to 0.3 Msun of stable iron and nickel isotopes, and then mix the ejecta strongly between the center and 0.8 Msun. We conclude that the supernovae that occur most frequently in nature are highly constrained by the Phillips relation and that a large part of the currently observed scatter in the relation is likely a consequence of the intrinsic diversity of these objects

The local FIR Galaxy Colour-Luminosity distribution: A reference for BLAST, and Herschel/SPIRE sub-mm surveys

We measure the local galaxy far-infrared (FIR) 60-to-100 um colour-luminosity distribution using an all-sky IRAS survey. This distribution is an important reference for the next generation of FIR--submillimetre surveys that have and will conduct deep extra-galactic surveys at 250--500 um. With the peak in dust-obscured star-forming activity leading to present-day giant ellipticals now believed to occur in sub-mm galaxies near z~2.5, these new FIR--submillimetre surveys will directly sample the SEDs of these distant objects at rest-frame FIR wavelengths similar to those at which local galaxies were observed by IRAS. We have taken care to correct for temperature bias and evolution effects in our IRAS 60 um-selected sample. We verify that our colour-luminosity distribution is consistent with measurements of the local FIR luminosity function, before applying it to the higher-redshift Universe. We compare our colour-luminosity correlation with recent dust-temperature measurements of sub-mm galaxies and find evidence for pure luminosity evolution of the form (1+z)^3. This distribution will be useful for the development of evolutionary models for BLAST and SPIRE surveys as it provides a statistical distribution of rest-frame dust temperatures for galaxies as a function of luminosity.Comment: 12 pages, 7 figures. MNRAS in press. This revision matches final published version. Fixes typos in footnote 1 and equation 8. Minor modifications to text and references. Final results unchange

CLEAR I: Ages and Metallicities of Quiescent Galaxies at 1.0<z<1.8\mathbf{1.0 < z < 1.8} Derived from Deep Hubble Space Telescope Grism Data

We use deep \textit{Hubble Space Telescope} spectroscopy to constrain the metallicities and (\editone{light-weighted}) ages of massive ($\log M_\ast/M_\odot\gtrsim10$) galaxies selected to have quiescent stellar populations at $1.0<z<1.8$. The data include 12--orbit depth coverage with the WFC3/G102 grism covering $\sim$ $8,000<\lambda<11,500$~\AA\, at a spectral resolution of $R\sim 210$ taken as part of the CANDELS Lyman-$\alpha$ Emission at Reionization (CLEAR) survey. At $1.0<z<1.8$, the spectra cover important stellar population features in the rest-frame optical. We simulate a suite of stellar population models at the grism resolution, fit these to the data for each galaxy, and derive posterior likelihood distributions for metallicity and age. We stack the posteriors for subgroups of galaxies in different redshift ranges that include different combinations of stellar absorption features. Our results give \editone{light-weighted ages of $t_{z \sim 1.1}= 3.2\pm 0.7$~Gyr, $t_{z \sim 1.2}= 2.2\pm 0.6$~Gyr, $t_{z\sim1.3}= 3.1\pm 0.6$~Gyr, and $t_{z\sim1.6}= 2.0 \pm 0.6$~Gyr, \editone{for galaxies at $z\sim 1.1$, 1.2, 1.3, and 1.6. This} implies that most of the massive quiescent galaxies at $168$\% of their stellar mass by a redshift of $z>2$}. The posteriors give metallicities of \editone{$Z_{z\sim1.1}=1.16 \pm 0.29$~$Z_\odot$, $Z_{z\sim1.2}=1.05 \pm 0.34$~$Z_\odot$, $Z_{z\sim1.3}=1.00 \pm 0.31$~$Z_\odot$, and $Z_{z\sim1.6}=0.95 \pm 0.39$~$Z_\odot$}. This is evidence that massive galaxies had enriched rapidly to approximately Solar metallicities as early as $z\sim3$.Comment: 32 pages, 23 figures, Resubmited to ApJ after revisions in response to referee repor

Seismic Radiation From Simple Models of Earthquakes

We review some basic features of shear wave generation and energy balance for a 2D anti plane rupture. We first study the energy balance for a flat fault, and for a fault that contains a single localized kink. We determine an exact expression for the partition between strain energy flow released from the elastic medium surrounding the fault, radiated energy flow and energy release rate. This balance depends only on the rupture speed and the residual stress intensity factor. When the fault contains a kink, the energy available for fracture is reduced so that the rupture speed is reduced. When rupture speed changes abruptly, the radiated energy flow also changes abruptly. As rupture propagates across the kink, a shear wave is emitted that has a displacement spectral content that decreases like ω^(-2) at high frequencies. We then use spectral elements to model the propagation of an antiplane crack with a slip-weakening friction law. Since the rupture front in this case has a finite length scale, the wave emitted by the kink is smoothed at very high frequencies but its general behavior is similar to that predicted by the simple sharp crack model. A model of a crack that has several kinks and wanders around a mean rupture directions, shows that kinks reduce the rupture speed along the average rupture direction of the fault. Contrary to flat fault models, a fault with kinks produces high frequency waves that are emitted every time the rupture front turns at a kink. Finally, we discuss the applicability of the present results to a 3D rupture model

Project of electrical low voltage installations in the industrial building

The purpose of the project is to perform calculations and studies required for the design of electrical supply to different receiver power and lighting of a warehouse energy, whose activity consists in treating metals, so that the planned facilities allow carry out the production process. The electrical needs of the company in terms of which the electrical installation will be projected, defining the technical and security features, and gathering the minimum conditions and guarantees required by current regulations, in order to obtain administrative authorization will be studied competent bodies for commissioning. It is undertake the design and calculation of the electrical installation for industrial building for a business of metallurgy