A Geometric Representation for the Proca Model

The Proca model is quantized in an open-path dependent representation that generalizes the Loop Representation of gauge theories. The starting point is a gauge invariant Lagrangian that reduces to the Proca Lagrangian when certain gauge is selected.Comment: 10 pages, Late

Molecular gas at supernova local environments unveiled by EDGE

CO observations allow estimations of the gas content of molecular clouds, which trace the reservoir of cold gas fuelling star formation, as well as to determine extinction via H$_2$ column density, N(H$_2$). Here, we studied millimetric and optical properties at 26 supernovae (SNe) locations of different types in a sample of 23 nearby galaxies by combining molecular $^{12}$C$^{16}$O (J = 1 $\rightarrow$ 0) resolved maps from the EDGE survey and optical Integral Field Spectroscopy from the CALIFA survey. We found an even clearer separation between type II and type Ibc SNe in terms of molecular gas than what we found in the optical using H$\alpha$ emission as a proxy for current SF rate, which reinforces the fact that SNe Ibc are more associated with SF-environments. While A$_V$ at SN locations is similar for SNe II and SNe Ibc, and higher compared to SNe Ia, N(H$_2$) is significantly higher for SNe Ibc than for SNe II and SNe Ia. When compared to alternative extinction estimations directly from SN photometry and spectroscopy, we find that our SNe Ibc have also redder color excess but showed standard Na I D absorption pseudo-equivalent widths ($\sim$1 \AA). In some cases we find no extinction when estimated from the environment, but high amounts of extinction when measured from SN observations, which suggests that circumstellar material or dust sublimation may be playing a role. This work serves as a benchmark for future studies combining last generation millimeter and optical IFS instruments to reveal the local environmental properties of extragalactic SNe.Comment: MNRAS accepted, 17 pages, 8 Figures, 4 Table

Robust formation of morphogen gradients

We discuss the formation of graded morphogen profiles in a cell layer by nonlinear transport phenomena, important for patterning developing organisms. We focus on a process termed transcytosis, where morphogen transport results from binding of ligands to receptors on the cell surface, incorporation into the cell and subsequent externalization. Starting from a microscopic model, we derive effective transport equations. We show that, in contrast to morphogen transport by extracellular diffusion, transcytosis leads to robust ligand profiles which are insensitive to the rate of ligand production

Serendipitous discovery of RR Lyrae stars in the Leo V ultra-faint galaxy

During the analysis of RR Lyrae stars discovered in the High cadence Transient Survey (HiTS) taken with the Dark Energy Camera at the 4-m telescope at Cerro Tololo Inter-American Observatory, we found a group of three very distant, fundamental mode pulsator RR Lyrae (type ab). The location of these stars agrees with them belonging to the Leo V ultra-faint satellite galaxy, for which no variable stars have been reported to date. The heliocentric distance derived for Leo V based on these stars is 173 +/- 5 kpc. The pulsational properties (amplitudes and periods) of these stars locate them within the locus of the Oosterhoff II group, similar to most other ultra-faint galaxies with known RR Lyrae stars. This serendipitous discovery shows that distant RR Lyrae stars may be used to search for unknown faint stellar systems in the outskirts of the Milky Way.Comment: Accepted in ApJ Letter

The Type IIn Supernova SN 2010bt: The Explosion of a Star in Outburst

Indexación: Scopus.It is well known that massive stars (M > 8 M ) evolve up to the collapse of the stellar core, resulting in most cases in a supernova (SN) explosion. Their heterogeneity is related mainly to different configurations of the progenitor star at the moment of the explosion and to their immediate environments. We present photometry and spectroscopy of SN 2010bt, which was classified as a Type IIn SN from a spectrum obtained soon after discovery and was observed extensively for about 2 months. After the seasonal interruption owing to its proximity to the Sun, the SN was below the detection threshold, indicative of a rapid luminosity decline. We can identify the likely progenitor with a very luminous star (log L/L ≈ 7) through comparison of Hubble Space Telescope images of the host galaxy prior to explosion with those of the SN obtained after maximum light. Such a luminosity is not expected for a quiescent star, but rather for a massive star in an active phase. This progenitor candidate was later confirmed via images taken in 2015 (∼5 yr post-discovery), in which no bright point source was detected at the SN position. Given these results and the SN behavior, we conclude that SN 2010bt was likely a Type IIn SN and that its progenitor was a massive star that experienced an outburst shortly before the final explosion, leading to a dense H-rich circumstellar environment around the SN progenitor. © 2018. The American Astronomical Society. All rights reserved.https://iopscience.iop.org/article/10.3847/1538-4357/aac51

The High Cadence Transit Survey (HiTS): Compilation and Characterization of Light-curve Catalogs

Indexación: Scopus.J.M. acknowledges support from CONICYT-Chile through CONICYT-PCHA/Doctorado-Nacional/2014-21140892. J.M., F.F., G.C.V., and G.M. acknowledge support from the Ministry of Economy, Development, and Tourism’s Millennium Science Initiative through grant IC120009, awarded to the Millennium Institute of Astrophysics (MAS). F.F. acknowledges support from Conicyt through the Fondecyt Initiation into Research project No. 11130228. J.M., F.F., J.S.M., G.C.V., and S.G. acknowledge support from Basal Project PFB-03, Centro de Modelamiento Matemáico (CMM), Universidad de Chile. P.L. acknowledges support by Fondecyt through project #1161184. G.C.V. gratefully acknowledges financial support from CON-ICYT-Chile through FONDECYT postdoctoral grant number 3160747 and CONICYT-Chile and NSF through the Programme of International Cooperation project DPI201400090. P.H. acknowledges support from FONDECYT through grant 1170305. L.G. was supported in part by the US National Science Foundation under grant AST-1311862. G.M. acknowledges support from Conicyt through CONICYT-PCHA/Magís-terNacional/2016-22162353. Support for T.d.J. has been provided by US NSF grant AST-1211916, the TABASGO Foundation, and Gary and Cynthia Bengier. R.R.M. acknowledges partial support from BASAL Project PFB-06, as well as FONDECYT project N◦1170364. Powered@NLHPC: this research was supported by the High Performance Computing infrastructure of the National Laboratory for High Performance Computing (NLHPC), PIA ECM-02, CONICYT. This project used data obtained with the Dark Energy Camera (DECam), which was constructed by the Dark Energy Survey (DES) collaborating institutions: Argonne National Lab, the University of California Santa Cruz, the University of Cambridge, Centro de Investigaciones Energeticas, Medioambientales y Tecnologi-cas-Madrid, the University of Chicago, University College London, the DES-Brazil consortium, the University of Edinburgh, ETH-Zurich, the University of Illinois at Urbana-Champaign, Institut de Ciencies de l’Espai, Institut de Fisica d’Altes Energies, Lawrence Berkeley National Lab, Ludwig-Maximilians Universitat, the University of Michigan, the National Optical Astronomy Observatory, the University of Nottingham, Ohio State University, the University of Pennsylvania, the University of Portsmouth, SLAC National Lab, Stanford University, the University of Sussex, and Texas A&M University. Funding for DES, including DECam, has been provided by the U.S. Department of Energy, National Science Foundation, Ministry of Education and Science (Spain), Science and Technology Facilities Council (UK), Higher Education Funding Council (England), National Center for Supercomputing Applications, Kavli Institute for Cosmological Physics, Financia-dora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparo a Pesquisa, Conselho Nacional de Desenvolvimento Científico e Tecnológico and the Ministério da Ciência e Tecnologia (Brazil), the German Research Foundation-sponsored cluster of excellence “Origin and Structure of the universe,” and the DES collaborating institutions. Facility: CTIO:1.5 m (DECam).The High Cadence Transient Survey (HiTS) aims to discover and study transient objects with characteristic timescales between hours and days, such as pulsating, eclipsing, and exploding stars. This survey represents a unique laboratory to explore large etendue observations from cadences of about 0.1 days and test new computational tools for the analysis of large data. This work follows a fully data science approach, from the raw data to the analysis and classification of variable sources. We compile a catalog of ∼15 million object detections and a catalog of ∼2.5 million light curves classified by variability. The typical depth of the survey is 24.2, 24.3, 24.1, and 23.8 in the u, g, r, and i bands, respectively. We classified all point-like nonmoving sources by first extracting features from their light curves and then applying a random forest classifier. For the classification, we used a training set constructed using a combination of cross-matched catalogs, visual inspection, transfer/active learning, and data augmentation. The classification model consists of several random forest classifiers organized in a hierarchical scheme. The classifier accuracy estimated on a test set is approximately 97%. In the unlabeled data, 3485 sources were classified as variables, of which 1321 were classified as periodic. Among the periodic classes, we discovered with high confidence one δ Scuti, 39 eclipsing binaries, 48 rotational variables, and 90 RR Lyrae, and for the nonperiodic classes, we discovered one cataclysmic variable, 630 QSOs, and one supernova candidate. The first data release can be accessed in the project archive of HiTS (http://astro.cmm.uchile.cl/HiTS/). © 2018. The American Astronomical Society. All rights reserved.https://iopscience.iop.org/article/10.3847/1538-3881/aadfd

Marine sponges of the genus neopetrosia with anti-inflammatory activity

The present study aimed to investigate the anti-inflammatory effect of marine sponges of the genus Neopetrosia which are abundant in the Colombian Caribbean. We obtained three fractions from a total methanolic extract of Neopetrosia rosariensis and proxima. In vivo activity was measured using λ-carrageenan-induced paw edema assay. The in vitro inhibitory effects were evaluated on myeloperoxidase activity (MPO) and nitric oxide (NO), prostaglandin E2 (PGE2), and tumor necrosis factor alpha (TNF- α) production. Total extracts of N. rosariensis and N. proxima (100 mg/Kg) significantly inhibited the paw edema of rats (71.74% and 60.06%, respectively). Dichloromethane and methanol fractions of Neopetrosia sponges reduced MPO activity. Only, dichloromethane fraction of N. rosariensis significantly inhibited NO (66%), PGE2 (30.5%) and TNF-α production (72%). Our results show anti-inflammatory activity in extracts and fractions from species of marine sponges belonging to Neopetrosia genus and open the way for complementary studies to purify and identify active molecules.Colegio de Farmacéuticos de la Provincia de Buenos Aire