Integral field observations of the blue compact galaxy Haro14. Star formation and feedback in dwarf galaxies

(Abridged) Low-luminosity, gas-rich blue compact galaxies (BCG) are ideal laboratories to investigate many aspects of the star formation in galaxies. We study the morphology, stellar content, kinematics, and the nebular excitation and ionization mechanism in the BCG Haro 14 by means of integral field observations with VIMOS in the VLT. From these data we build maps in continuum and in the brighter emission lines, produce line-ratio maps, and obtain the velocity and velocity dispersion fields. We also generate the integrated spectrum of the major HII regions and young stellar clusters identified in the maps to determine reliable physical parameters and oxygen abundances. We find as follows: i) the current star formation in Haro 14 is spatially extended with the major HII regions placed along a linear structure, elongated in the north-south direction, and in a horseshoe-like curvilinear feature that extends about 760 pc eastward; the continuum emission is more concentrated and peaks close to the galaxy center; ii) two different episodes of star formation are present: the recent starburst, with ages $\leq$ 6 Myrs and the intermediate-age clusters, with ages between 10 and 30 Myrs; these stellar components rest on a several Gyr old underlying host galaxy; iii) the H$\alpha$/H$\beta$ pattern is inhomogeneous, with excess color values varying from E(B-V)=0.04 up to E(B-V)=1.09; iv) shocks play a significant role in the galaxy; and v) the velocity field displays a complicated pattern with regions of material moving toward us in the east and north galaxy areas. The morphology of Haro 14, its irregular velocity field, and the presence of shocks speak in favor of a scenario of triggered star formation. Ages of the knots are consistent with the ongoing burst being triggered by the collective action of stellar winds and supernovae originated in the central clusters.Comment: 18 pages, 17 figures. Accepted for publication in A&

Probing star formation and feedback in dwarf galaxies. Integral field view of the blue compact galaxy Tololo 1937-423

(Abridged) Blue compact galaxies (BCG) are gas-rich, low-mass, small systems that form stars at unusually high rates. This makes them excellent laboratories for investigating the process of star-formation (SF) at galactic scales and the effects of massive stellar feedback on the interstellar (and intergalactic) medium. We analyzed the BCG Tololo 1937-423 using optical integral field spectroscopy with VIMOS at the Very Large Telescope to probe its morphology, stellar content, nebular excitation and ionization properties, and the kinematics of its warm ionized gas. We found that Tololo 1937-423 is currently undergoing an extended starburst, with nine major $H\alpha$ clumps. The galaxy presents a single continuum peak that is not cospatial with any knot in emission lines, indicating at least two relatively recent episodes of SF. The inhomogeneous dust distribution reaches its maximum roughly at the position of the continuum peak. We found shocked regions in the galaxy outer regions and at the edges of the SF knots. The oxygen abundance is similar in all the SF regions, suggesting a chemically homogeneous ionized interstellar medium over spatial scales of several kpc. The ionized gas kinematics displays an overall regular rotation around a northwest-southeast axis. The morphology of the galaxy and the two different episodes of SF suggest a scenario of triggered (induced by supernova shock waves) SF acting in Tololo 1937-423. The inferred ages for the different SF episodes (~13-80 Myr for the central post-starburst and 5-7 Myr for the ongoing SF) are consistent with triggered SF, with the most recent SF episode caused by the collective effect of stellar winds and supernova explosions from the central post-starburst. The velocity dispersion pattern, with higher velocity dispersions found at the edges of the SF regions, and shocked regions in the galaxy, also favor this scenario.Comment: 16 pages, 18 figures. Accepted for publication in A&

Understanding star formation and feedback in small galaxies. The case of the blue compact dwarf Mrk 900

(Abridged) Low-luminosity, active star-forming blue compact galaxies (BCGs) are excellent laboratories for investigating the process of star formation on galactic scales and probing the interplay between massive stars and the surrounding interstellar (or intergalactic) medium. We investigated the morphology, structure, and stellar content of the Blue Compact Galaxy Mrk 900, combining optical integral field observations obtained with VIMOS at the VLT and deep broad-band photometry taken at the 2.5 m NOT telescope. From the integral field data, we built continuum, emission, and diagnostic line ratio maps and produced velocity and velocity dispersion maps. We also generated the integrated spectrum of the major HII regions and the nuclear area to determine reliable physical parameters and oxygen abundances. The broad-band data, tracing the galaxy up to radius 4 kpc, allowed us to investigate the properties of the low surface brightness underlying stellar host. We disentangle two different stellar components in Mrk 900: a young population, which resolves into individual stellar clusters with ages ~5.5-6.6 Myr and extends about 1 kpc along the galaxy minor axis, is placed on top of a rather red and regular shaped underlying stellar host, several Gyr old. We find evidence of a substantial amount of dust and an inhomogeneous extinction pattern, with a dust lane crossing the central starburst. Mrk 900 displays overall rotation, although distorted in the central, starburst regions; the dispersion velocity map is highly inhomogeneous, with values increasing up to 60 kms$^{-1}$ at the periphery of the SF regions, where we also find hints of the presence of shocks. Our observational results point to an interaction or merger with a low-mass object or infalling gas as plausible trigger mechanisms for the present starburst event.Comment: 17 pages, 19 figures. Accepted for publication in A&

The Ca II infrared triplet's performance as an activity indicator compared to Ca II H and K

Aims. A large number of Calcium Infrared Triplet (IRT) spectra are expected from the GAIA- and CARMENES missions. Conversion of these spectra into known activity indicators will allow analysis of their temporal evolution to a better degree. We set out to find such a conversion formula and to determine its robustness. Methods. We have compared 2274 Ca II IRT spectra of active main-sequence F to K stars taken by the TIGRE telescope with those of inactive stars of the same spectral type. After normalizing and applying rotational broadening, we subtracted the comparison spectra to find the chromospheric excess flux caused by activity. We obtained the total excess flux, and compared it to established activity indices derived from the Ca II H & K lines, the spectra of which were obtained simultaneously to the infrared spectra. Results. The excess flux in the Ca II IRT is found to correlate well with $R_\mathrm{HK}'$ and $R_\mathrm{HK}^{+}$, as well as $S_\mathrm{MWO}$, if the $B-V$-dependency is taken into account. We find an empirical conversion formula to calculate the corresponding value of one activity indicator from the measurement of another, by comparing groups of datapoints of stars with similar B-V.Comment: 16 pages, 15 figures. Accepted for publication in Astronomy & Astrophysic

Uv-to-fir analysis of spitzer/irac sources in the extended groth strip i: Multi-wavelength photometry and spectral energy distributions

We present an IRAC 3.6+4.5 microns selected catalog in the Extended Groth Strip (EGS) containing photometry from the ultraviolet to the far-infrared and stellar parameters derived from the analysis of the multi-wavelength data. In this paper, we describe the method used to build coherent spectral energy distributions (SEDs) for all the sources. In a companion paper, we analyze those SEDs to obtain robust estimations of stellar parameters such as photometric redshifts, stellar masses, and star formation rates. The catalog comprises 76,936 sources with [3.6]<23.75 mag (85% completeness level of the IRAC survey in the EGS) over 0.48 square degrees. For approximately 16% of this sample, we are able to deconvolve the IRAC data to obtain robust fluxes for the multiple counterparts found in ground-based optical images. Typically, the SEDs of the IRAC sources in our catalog count with more than 15 photometric data points, spanning from the UV to the FIR. Approximately 95% and 90% of all IRAC sources are detected in the deepest optical and near-infrared bands. Only 10% of the sources have optical spectroscopy and redshift estimations. Almost 20% and 2% of the sources are detected by MIPS at 24 and 70 microns, respectively. We also cross-correlate our catalog with public X-ray and radio catalogs. Finally, we present the Rainbow Navigator public web-interface utility designed to browse all the data products resulting from this work, including images, spectra, photometry, and stellar parameters.Comment: 28 pages, 12 figures, Accepted for publication in ApJ. Access the Rainbow Database at: http://rainbowx.fis.ucm.e

Ovine HSP90AA1 Expression Rate Is Affected by Several SNPs at the Promoter under Both Basal and Heat Stress Conditions

The aim of this work was to investigate the association between polymorphisms located at the HSP90AA1 ovine gene promoter and gene expression rate under different environmental conditions, using a mixed model approach. Blood samples from 120 unrelated rams of the Manchega sheep breed were collected at three time points differing in environmental conditions. Rams were selected on the basis of their genotype for the transversion G/C located 660 base pairs upstream the gene transcription initiation site. Animals were also genotyped for another set of 6 SNPs located at the gene promoter. Two SNPs, G/C-660 and A/G-444, were associated with gene overexpression resulting from heat stress. The composed genotype CC-660-AG-444 was the genotype having the highest expression rates with fold changes ranging from 2.2 to 3.0. The genotype AG-522 showed the highest expression levels under control conditions with a fold change of 1.4. Under these conditions, the composed genotype CC-601-TT-524-AG-522-TT-468 is expected to be correlated with higher basal expression of the gene according to genotype frequencies and linkage disequilibrium values. Some putative transcription factors were predicted for binding sites where the SNPs considered are located. Since the expression rate of the gene under alternative environmental conditions seems to depend on the composed genotype of several SNPs located at its promoter, a cooperative regulation of the transcription of the HSP90AA1 gene could be hypothesized. Nevertheless epigenetic regulation mechanisms cannot be discarded. © 2013 Salces-Ortiz et al

USCID fourth international conference

Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.Includes bibliographical references.This study, carried out between October 2004 and November 2005 on the island of Tenerife, covers: (1) characterization of the irrigated crops and quantification of the gross irrigation requirements (GIRs) of each crop using surveys; (2) field evaluation of drip/micro, spray and sprinkle irrigation systems to obtain global distribution uniformity (DU) as indicated by the Cal Poly ITRC (Irrigation Training and Research Centre, California Polytechnic State University, San Luis Obispo, California, USA); (3) analysis of on farm irrigation efficiency using local climatic data; and (4) inclusion of this data into a Geographic Information System (GIS). Crop GIRs show high deviations mainly because of the multiple microclimate conditions on the island, the irrigation methods used, the crop systems (greenhouses, etc) and the irrigation management. Field evaluation provided an average DU of 0.83 in drip/micro and spray irrigated banana crops, 0.69 in sprinkle irrigated ones, 0.58 in sprinkle irrigated horticulture and 0.81 for tomato crops (100% drip). Data showed that approximately 30% of the non-uniformity was due to pressure differences in the irrigation system, 3% due to unequal drainage, 7% due to unequal application rates, and 60% was due to other causes (which include manufacturing variation, plugging, and wear). Irrigation efficiency is around 80% in drip irrigated tomato and banana crops and 75% in sprinkle systems. Data showed that efficiency is slightly lower in greenhouses and mesh greenhouse crops than in non-protected crops basically due to the fact that although protected crops require less water, they receive an equal quantity of water. Inclusion of the data into a GIS makes possible a high level of agronomic water consumption control on the island

Investigating evidence for different black hole accretion modes since redshift z~1

Chandra data in the COSMOS, AEGIS-XD and 4Ms CDFS are combined with optical/near-IR photometry to determine the rest-frame U-V vs V-J colours of X-ray AGN hosts at mean redshifts 0.40 and 0.85. This combination of colours (UVJ) provides an efficient means of separating quiescent from star-forming, including dust reddened, galaxies. Morphological information emphasises differences between AGN split by their UVJ colours. AGN in quiescent galaxies are dominated by spheroids, while star-forming hosts are split between bulges and disks. The UVJ diagram of AGN hosts is then used to set limits on the accretion density associated with evolved and star-forming systems. Most of the black hole growth since z~1 is associated with star-forming hosts. Nevertheless, ~15-20% of the X-ray luminosity density since z~1, is taking place in the quiescent region of the UVJ diagram. For the z~0.40 subsample, there is tentative evidence (2sigma significance), that AGN split by their UVJ colours differ in Eddington ratio. AGN in star-forming hosts dominate at high Eddington ratios, while AGN in quiescent hosts become increasingly important as a fraction of the total population toward low Eddington ratios. At higher redshift, z~0.8, such differences are significant at the 2sigma level only at Eddington ratios >1e-3. These findings are consistent with scenarios in which diverse accretion modes are responsible for the build-up of SMBHs at the centres of galaxies. We compare our results with the GALFORM semi-analytic model, which postulates two black hole fuelling modes, the first linked to star-formation and the second occuring in passive galaxies. GALFORM predicts a larger fraction of black hole growth in quiescent galaxies at z<1, compared to the data. Relaxing the strong assumption of the model that passive AGN hosts have zero star-formation rate could reconcile this disagreement.Comment: MNRAS accepte

Role of lysosomal enzymes released by alveolar macrophages in the pathogenesis of the acute phase of hypersensitivity pneumonitis

Hydrolytic enzymes are the major constituents of alveolar macrophages (AM) and have been shown to be involved in many aspects of the inflammatory pulmonary response. The aim of this study was to evaluate the role of lysosomal enzymes in the acute phase of hypersensitivity pneumonitis (HPs). An experimental study on AM lysosomal enzymes of an HP-guinea-pig model was performed. The results obtained both in vivo and in vitro suggest that intracellular enzymatic activity decrease is, at least partly, due to release of lysosomal enzymes into the medium. A positive but slight correlation was found between extracellular lysosomal activity and four parameters of lung lesion (lung index, bronchoalveolar fluid total (BALF) protein concentration, BALF LDH and BALF alkaline phosphatase activities). All the above findings suggest that the AM release of lysosomal enzymes during HP is a factor involved, although possibly not the only one, in the pulmonary lesions appearing in this disease