Cluster and field elliptical galaxies at z~1.3. The marginal role of the environment and the relevance of the galaxy central regions

We compared the properties of 56 elliptical galaxies selected from three clusters at $1.2<z<1.4$ with those of field galaxies in the GOODS-S (~30), COSMOS (~180) and CANDELS (~220) fields. We studied the relationships among effective radius, surface brightness, stellar mass, stellar mass density $\Sigma_{Re}$ and central mass density $\Sigma_{1kpc}$ within 1 kpc radius. We find that cluster ellipticals do not differ from field ellipticals: they share the same structural parameters at fixed mass and the same scaling relations. On the other hand, the population of field ellipticals at $z\sim1.3$ shows a significant lack of massive ($M_*> 2\times 10^{11}$ M$_\odot$) and large (R$_e > 4-5$ kpc) ellipticals with respect to the cluster. Nonetheless, at $M*<2\times 10^{11}$ M$_\odot$, the two populations are similar. The size-mass relation of ellipticals at z~1.3 defines two different regimes, above and below a transition mass $m_t\sim 2-3\times10^{10}$ M$_\odot$: at lower masses the relation is nearly flat (R$_e\propto M_*^{-0.1\pm 0.2}$), the mean radius is constant at ~1 kpc and $\Sigma_{Re}\sim \Sigma_{1kpc}$ while, at larger masses, the relation is R$_e\propto M*^{0.64\pm0.09}$. The transition mass marks the mass at which galaxies reach the maximum $\Sigma_{Re}$. Also the $\Sigma_{1kpc}$-mass relation follows two different regimes, $\Sigma_{1kpc}\propto M*^{0.64\ >m_t}_{1.07\ <m_t}$, defining a transition mass density $\Sigma_{1kpc}\sim 2-3\times10^3$ M$_\odot$ pc$^{-2}$. The mass density $\Sigma_{Re}$ does not correlate with mass, dense/compact galaxies can be assembled over a wide mass regime, independently of the environment. The central mass density, $\Sigma_{1kpc}$, besides to be correlated with the mass, is correlated to the age of the stellar population: the higher the central stellar mass density, the higher the mass, the older the age of the stellar population. [Abridged]Comment: Accepted for publication in A&A; 20 pages, 13 figures (replaced to match the A&A version

Age, metallicity and star formation history of spheroidal galaxies in cluster at z~1.2

We present the analysis, based on spectra collected at the Large Binocular Telescope, of the stellar populations in seven spheroidal galaxies in the cluster XLSSJ0223 at $z$$\sim$1.22. The aim is to constrain the epoch of their formation and their star formation history. Using absorption line strenghts and full spectral fitting, we derive for the stellar populations of the seven spheroids a median age =2.4$\pm$0.6 Gyr, corresponding to a median formation redshift $\sim2.6_{-0.5}^{+0.7}$ (lookback time = 11$_{-1.0}^{+0.6}$ Gyr). We find a significant scatter in age, showing that massive spheroids, at least in our targeted cluster, are not coeval. The median metallicity is [Z/H]=0.09$\pm$0.16, as for early-types in clusters at 0$<z$<0.9. This lack of evolution of [Z/H] over the range 0$<$$z$$<$1.3, corresponding to the last 9 billions years, suggests that no significant additional star formation and chemical enrichment are required for cluster spheroids to reach the present-day population. We do not detect significant correlation between age and velocity dispersion$\sigma_e$, or dynamical mass M$_{dyn}$, or effective stellar mass density$\Sigma_e$. On the contrary, the metallicity [Z/H] of the seven spheroids is correlated to their dynamical mass M$_{dyn}$, according to a relation similar to the one for local spheroids. [Z/H] is also anticorrelated to stellar mass density$\Sigma_e$because of the anticorrelation between M$_{dyn}$and$\Sigma_e$. Therefore, the basic trends observed in the local universe were already established at$z\sim1.3$, i.e. more massive spheroids are more metal rich, have lower stellar mass density and tend to be older than lower-mass galaxies.Comment: 16 pages, 6 figures, 6 tables, published on MNRA

Compressive Phase Contrast Tomography

When x-rays penetrate soft matter, their phase changes more rapidly than their amplitude. In- terference effects visible with high brightness sources creates higher contrast, edge enhanced images. When the object is piecewise smooth (made of big blocks of a few components), such higher con- trast datasets have a sparse solution. We apply basis pursuit solvers to improve SNR, remove ring artifacts, reduce the number of views and radiation dose from phase contrast datasets collected at the Hard X-Ray Micro Tomography Beamline at the Advanced Light Source. We report a GPU code for the most computationally intensive task, the gridding and inverse gridding algorithm (non uniform sampled Fourier transform).Comment: 5 pages, "Image Reconstruction from Incomplete Data VI" conference 7800, SPIE Optical Engineering + Applications 1-5 August 2010 San Diego, CA United State

Charge asymmetry in hadroproduction of heavy quarks

A sizeable difference in the differential production cross section of top and antitop quarks, respectively, is predicted for hadronically produced heavy quarks. It is of order $\alpha_s$ and arises from the interference between charge odd and even amplitudes respectively. For the TEVATRON it amounts to approximately 5-10% in the region where the cross section is large and could therefore be measured in the next round of experiments. At the LHC the asymmetry can be studied by selecting appropriately chosen kinematical regions.Comment: LaTeX, 5pp, 5 figures, uses revtex. The complete paper, including figures, is also available via anonymous ftp at ftp://ttpux2.physik.uni-karlsruhe.de/ , or via www at http://www-ttp.physik.uni-karlsruhe.de/cgi-bin/preprints/ Final version as published in Phys.Rev.Let

Iterative Algorithms for Ptychographic Phase Retrieval

Ptychography promises diffraction limited resolution without the need for high resolution lenses. To achieve high resolution one has to solve the phase problem for many partially overlapping frames. Here we review some of the existing methods for solving ptychographic phase retrieval problem from a numerical analysis point of view, and propose alternative methods based on numerical optimization.Comment: 32 pages, 15 figure

Zooming-in on Instantons at HERA

In view of the intriguing, preliminary search results for instanton-induced events at HERA from the H1 collaboration, some important remaining theoretical issues are discussed. Notably, the question is addressed, to which extent the H1 analysis may be directly compared to our original predictions from instanton-perturbation theory, since certain fiducial cuts are lacking in the H1 data. Various theoretical uncertainties are evaluated and their impact on the observed excess is discussed. An improved understanding of the experimental findings along with an encouraging over-all agreement with our original predictions seems to emerge.Comment: 13 pages, 12 figure

Dijet Event Shapes as Diagnostic Tools

Event shapes have long been used to extract information about hadronic final states and the properties of QCD, such as particle spin and the running coupling. Recently, a family of event shapes, the angularities, has been introduced that depends on a continuous parameter. This additional parameter-dependence further extends the versatility of event shapes. It provides a handle on nonperturbative power corrections, on non-global logarithms, and on the flow of color in the final state.Comment: 18 pages, 3 figure

Uncommon differential diagnosis of a breast ulcer: A case study

Introduction: Spider bites are common worldwide. Frequently symptoms resolve without any adverse outcome, but in rare cases the bite can cause severe morbidity. The most typical presentation of Mediterranean recluse spider (Loxosceles Rufescens) bite is a dermatonecrotic lesion of the skin (skin loxoscelism). When the only manifestation of a spider bite is an ulcerated skin lesion, clinical suspicion and differential diagnosis strongly depend on its site. We present the case of an ulcerated wound of the breast, diagnosed as a Mediterranean recluse spider bite. Case presentation: A 79-year-old woman presented a 10cm-wide soft tissue ulceration of her left breast. At first, the diagnostic hypothesis of an ulcerated cancer was ruled out. Two family members revealed a recent history of Mediterranean recluse spider bite and the same clinical diagnosis was made for our patient. A wide excision was performed, with complete resolution of symptoms. Discussion: No specific diagnostic criteria for spider bites are available. Diagnosis is usually clinical. Skin loxoscelism could be easily mistaken for cellulitis, various types of skin infections, cutaneous anthrax, vasculitis, scorpion sting, pyoderma gangrenosum, erythema migrans of Lyme disease or prurigo nodularis. A thorough anamnestic interview is fundamental to raise the diagnostic hypothesis. When possible, a biopsy is recommended and it is extremely important when the ulcer can mimic a cancer, as is the case in breast tissue. Conclusion: We recommend a wide excision of the wound after failure of conservative treatment, in order to obtain local control and to perform histological examination on a more representative specimen. Declaration of interest: The authors have no conflicts of interest to declare