Cuticle of 'Gala' and 'Galaxy' Apples Cultivars under Different Environmental Conditions

This study aimed to analyze the cuticle thickness and pattern of epicuticular wax deposition in 'Gala' and 'Galaxy' apple cultivars (Malus domestica Borkh,) from three Brazilian producing areas: Vacaria (RS), Fraiburgo (SC) and Sao Joaquim (SC) with altitudes of 971, 1,048 and 1,353m, respectively. Harvested fruit were kept under two storage conditions: regular atmosphere (RA) (0 degrees C and 90% RH) and controlled atmosphere (CA) (1.5% O-2, 2.5% CO2, 0 degrees C and 90% RH). Cuticle thickness measurements were made using LM and the deposition pattern of epicuticular wax observed with a SEM. Altitude among the apple producing areas was not a factor in deposition pattern of waxes between the cultivars but at higher altitudes, the cuticle was thicker in both the cultivars. In the freshly-harvested fruits, waxes deposition in the form of platelets and the mechanism of "tear and repair" were observed. Severity of microcracks in the cuticle was more evident on the fruits from CA.

FINDING FOSSIL GROUPS: OPTICAL IDENTIFICATION AND X-RAY CONFIRMATION

We report the discovery of 12 new fossil groups (FGs) of galaxies, systems dominated by a single giant elliptical galaxy and cluster-scale gravitational potential, but lacking the population of bright galaxies typically seen in galaxy clusters. These FGs, selected from the maxBCG optical cluster catalog, were detected in snapshot observations with the Chandra X-ray Observatory. We detail the highly successful selection method, with an 80% success rate in identifying 12 FGs from our target sample of 15 candidates. For 11 of the systems, we determine the X-ray luminosity, temperature, and hydrostatic mass, which do not deviate significantly from expectations for normal systems, spanning a range typical of rich groups and poor clusters of galaxies. A small number of detected FGs are morphologically irregular, possibly due to past mergers, interaction of the intra-group medium with a central active galactic nucleus (AGN), or superposition of multiple massive halos. Two-thirds of the X-ray-detected FGs exhibit X-ray emission associated with the central brightest cluster galaxy (BCG), although we are unable to distinguish between AGN and extended thermal galaxy emission using the current data. This sample representing a large increase in the number of known FGs, will be invaluable for future planned observations to determine FG temperature, gas density, metal abundance, and mass distributions, and to compare to normal (non-fossil) systems. Finally, the presence of a population of galaxy-poor systems may bias mass function determinations that measure richness from galaxy counts. When used to constrain power spectrum normalization and Omega(m), these biased mass functions may in turn bias these results.

Galaxy interactions I. Major and minor mergers

Aims. We study galaxy pair samples selected from the Sloan Digital Sky Survey (SDSS-DR7) and we perform an analysis of minor and major mergers with the aim of investigating the dependence of galaxy properties on interactions. Methods. We build a galaxy pair catalog requiring r(p) < 25 kpc h(-1) and Delta V < 350 km s(-1) within redshift z < 0.1. By visual inspection of SDSS images we remove false identifications and we classify the interactions into three categories: pairs undergoing merging, M; pairs with evident tidal features, T; and non disturbed, N. We also divide the pair sample into minor and major interactions according to the luminosity ratio of the galaxy members. We study star formation activity through colors, the 4000 angstrom break, and star formation rates. Results. We find that similar to 10% of the pairs are classified as M. These systems show an excess of young stellar populations as inferred from the D-n(4000) spectral index, colors, and star formation rates of the member galaxies, an effect which we argue is directly related to the ongoing merging process. We find similar to 30% of the pairs exhibiting tidal features (T pairs) with member galaxies showing evidence of old stellar populations. This can be associated either to the disruptive effect of some tidal interactions, or to the longer time-scale of morphological disturbance with respect to the bursts of the tidal induced star formation. Regardless of the color distribution, we find a prominent blue peak in the strongest mergers, while pairs with tidal signs under a minor merger show a strong red peak. Therefore, our results show that galaxy interactions are important in driving the evolution of galaxy bimodality. By adding stellar masses and star formation rates of the two members of the pairs, we explore the global efficiency of star formation of the pairs as a whole. We find that, at a given total stellar mass, major mergers are significantly more efficient (a factor approximate to 2) in forming new stars, with respect to both minor mergers or a control sample of non-interacting galaxies. We conclude that the characteristics of the interactions and the ratio of luminosity galaxy pair members involved in a merger are important parameters in setting galaxy properties.

THE SLOAN DIGITAL SKY SURVEY CO-ADD: A GALAXY PHOTOMETRIC REDSHIFT CATALOG

We present and describe a catalog of galaxy photometric redshifts (photo-z) for the Sloan Digital Sky Survey (SDSS) Co-add Data. We use the artificial neural network (ANN) technique to calculate the photo-z and the nearest neighbor error method to estimate photo-z errors for similar to 13 million objects classified as galaxies in the co-add with r < 24.5. The photo-z and photo-z error estimators are trained and validated on a sample of similar to 83,000 galaxies that have SDSS photometry and spectroscopic redshifts measured by the SDSS Data Release 7 (DR7), the Canadian Network for Observational Cosmology Field Galaxy Survey, the Deep Extragalactic Evolutionary Probe Data Release 3, the VIsible imaging Multi-Object Spectrograph-Very Large Telescope Deep Survey, and the WiggleZ Dark Energy Survey. For the best ANN methods we have tried, we find that 68% of the galaxies in the validation set have a photo-z error smaller than sigma(68) = 0.031. After presenting our results and quality tests, we provide a short guide for users accessing the public data.

Milky Way demographics with the VVV survey I. The 84-million star colour-magnitude diagram of the Galactic bulge

Context. The Milky Way (MW) bulge is a fundamental Galactic component for understanding the formation and evolution of galaxies, in particular our own. The ESO Public Survey VISTA Variables in the Via Lactea is a deep near-IR survey mapping the Galactic bulge and southern plane. Particularly for the bulge area, VVV is covering similar to 315 deg(2). Data taken during 2010 and 2011 covered the entire bulge area in the JHKs bands. Aims. We used VVV data for the whole bulge area as a single and homogeneous data set to build for the first time a single colour-magnitude diagram (CMD) for the entire Galactic bulge. Methods. Photometric data in the JHK(s) bands were combined to produce a single and huge data set containing 173 150 467 sources in the three bands, for the similar to 315 deg(2) covered by VVV in the bulge. Selecting only the data points flagged as stellar, the total number of sources is 84 095 284. Results. We built the largest colour-magnitude diagrams published up to date, containing 173.1+ million sources for all data points, and more than 84.0 million sources accounting for the stellar sources only. The CMD has a complex shape, mostly owing to the complexity of the stellar population and the effects of extinction and reddening towards the Galactic centre. The red clump (RC) giants are seen double in magnitude at b similar to -8 degrees-10 degrees, while in the inner part (b similar to -3 degrees) they appear to be spreading in colour, or even splitting into a secondary peak. Stellar population models show the predominance of main-sequence and giant stars. The analysis of the outermost bulge area reveals a well-defined sequence of late K and M dwarfs, seen at (J - K-s) similar to 0.7-0.9 mag and K-s greater than or similar to 14 mag. Conclusions. The interpretation of the CMD yields important information about the MW bulge, showing the fingerprint of its structure and content. We report a well-defined red dwarf sequence in the outermost bulge, which is important for the planetary transit searches of VVV. The double RC in magnitude seen in the outer bulge is the signature of the X-shaped MW bulge, while the spreading of the RC in colour, and even its splitting into a secondary peak, are caused by reddening effects. The region around the Galactic centre is harder to interpret because it is strongly affected by reddening and extinction.

Star formation in H I tails: HCG 92, HCG 100 and six interacting systems

We present new Gemini spectra of 14 new objects found within the H?i tails of Hickson Compact Groups (HCGs) 92 and 100. Nine of them are Galaxy Evolution Explorer (GALEX) far-ultraviolet (FUV) and near-ultraviolet (NUV) sources. The spectra confirm that these objects are members of the compact groups and have metallicities close to solar, with an average value of 12+log(O/H) similar to 8.5. They have average FUV luminosities 7 x 10(40)?erg?s-1 and very young ages (<100?Myr), and two of them resemble tidal dwarf galaxy (TDG) candidates. We suggest that they were created within gas clouds that were ejected during galaxygalaxy interactions into the intergalactic medium, which would explain the high metallicities of the objects, inherited from the parent galaxies from which the gas originated. We conduct a search for similar objects in six interacting systems with extended H?i tails: NGC 2623, NGC 3079, NGC 3359, NGC 3627, NGC 3718 and NGC 4656. We found 35 ultraviolet (UV) sources with ages < 100?Myr; however, most of them are on average less luminous/massive than the UV sources found around HCG 92 and HCG 100. We speculate that this might be an environmental effect and that compact groups of galaxies are more favourable to TDG formation than other interacting systems.

THE ROLE OF DARK MATTER INTERACTION IN GALAXY CLUSTERS

We consider a toy del to analyze the consequences of dark matter interaction with a dark energy background on the overall rotation of galaxy clusters and the misalignment between their dark matter and baryon distributions when compared to ACDM predictions. The interaction parameters are found via a genetic algorithm search. The results obtained suggest that interaction is a basic phenomenon whose effects are detectable even in simple models of galactic dynamics.

Cuticle of 'Gala' and 'Galaxy' apples cultivars under different environmental conditions

This study aimed to analyze the cuticle thickness and pattern of epicuticular wax deposition in 'Gala' and 'Galaxy' apple cultivars (Malus domestica Borkh,) from three Brazilian producing areas: Vacaria (RS), Fraiburgo (SC) and São Joaquim (SC) with altitudes of 971, 1,048 and 1,353m, respectively. Harvested fruit were kept under two storage conditions: regular atmosphere (RA) (0 ºC and 90% RH) and controlled atmosphere (CA) (1.5% O2, 2.5% CO2, 0ºC and 90% RH). Cuticle thickness measurements were made using LM and the deposition pattern of epicuticular wax observed with a SEM. Altitude among the apple producing areas was not a factor in deposition pattern of waxes between the cultivars but at higher altitudes, the cuticle was thicker in both the cultivars. In the freshly-harvested fruits, waxes deposition in the form of platelets and the mechanism of tear and repair were observed. Severity of microcracks in the cuticle was more evident on the fruits from CA.

The star formation rate in the inner Milky Way Galaxy

The present star formation rate (SFR) in the inner Galaxy is puzzling for the chemical evolution models (CEM). No static CEM is able to reproduce the peak of the SFR in the 4 kpc ring. The main reason is probably a shortage of gas, which could be due to the dynamical effects produced by the galactic bar, not considered by these models. We developed a CEM that includes radial gas flows in order to mimic the effects of the galactic bar in the first 5 kpc of the galactic disk. In this model, the star formation (SF) is a two-step process: first, the diffuse gas forms molecular clouds. Then, stars form from cloud-cloud collisions or by the interaction between massive stars and the molecular gas. The former is called spontaneous and the latter induced SF. The mass in the different phases of each region changes by the processes associated with the stellar formation and death by: the SF due to spontaneous fragmentation of gas in the halo; formation of gas clouds in the disk from the diffuse gas; induced SF in the disk due to the interaction between massive stars and gas clouds; and finally, the restitution of the diffuse gas associated to these process of cloud and star formation. In the halo, the star formation rate for the diffuse gas follows a Schmidt law with a power n = 1.5. In the disk, the stars form in two steps: first, molecular clouds are formed from the diffuse gas also following a Schmidt law with n=1.5 and a proportionality factor. Including a specific pattern of radial gas flows, the CEM is able to reproduce with success the peak in the SFR at 4 kpc (fig. 1).

Testing phenomenological and theoretical models of dark matter density profiles with galaxy clusters

We use the stacked gravitational lensingmass profile of four high-mass (M 1015M ) galaxy clusters around z≈0.3 from Umetsu et al. to fit density profiles of phenomenological [Navarro– Frenk–White (NFW), Einasto, S´ersic, Stadel, Baltz–Marshall–Oguri (BMO) and Hernquist] and theoretical (non-singular Isothermal Sphere, DARKexp and Kang & He) models of the dark matter distribution. We account for large-scale structure effects, including a two-halo term in the analysis.We find that the BMO model provides the best fit to the data as measured by the reduced χ2. It is followed by the Stadel profile, the generalized NFW profile with a free inner slope and by the Einasto profile. The NFW model provides the best fit if we neglect the two-halo term, in agreement with results from Umetsu et al. Among the theoretical profiles, the DARKexp model with a single form parameter has the best performance, very close to that of the BMO profile. This may indicate a connection between this theoretical model and the phenomenology of dark matter haloes, shedding light on the dynamical basis of empirical profiles which emerge from numerical simulations.

A galaxy model from Two Micron All Sky Survey star counts in the whole sky, including the plane

We use the star count model of Ortiz & Lépine to perform an unprecedented exploration of the most important Galactic parameters comparing the predicted counts with the Two Micron All Sky Survey observed star counts in the J, H, and KS bands for a grid of positions covering the whole sky. The comparison is made using a grid of lines of sight given by the HEALPix pixelization scheme. The resulting best-fit values for the parameters are: 2120 ± 200 pc for the radial scale length and 205 ± 40 pc for the scale height of the thin disk, with a central hole of 2070$_{-800}^{+2000}$ pc for the same disk, 3050 ± 500 pc for the radial scale length and 640 ± 70 pc for the scale height of the thick disk, 400 ± 100 pc for the central dimension of the spheroid, 0.0082 ± 0.0030 for the spheroid to disk density ratio, and 0.57 ± 0.05 for the oblate spheroid parameter.

Galaxy triplets in Sloan Digital Sky Survey Data Release 7: II. A connection with compact groups?

We analyse a sample of 71 triplets of luminous galaxies derived from the work of O’Mill et al. We compare the properties of triplets and their members with those of control samples of compact groups, the 10 brightest members of rich clusters and galaxies in pairs. The triplets are restricted to have members with spectroscopic redshifts in the range 0.01 ≤ z ≤ 0.14 and absolute r-band luminosities brighter than Mr = −20.5. For these member galaxies, we analyse the stellar mass content, the star formation rates, the Dn(4000) parameter and (Mg − Mr) colour index. Since galaxies in triplets may finally merge in a single system, we analyse different global properties of these systems. We calculate the probability that the properties of galaxies in triplets are strongly correlated. We also study total star formation activity and global colours, and define the triplet compactness as a measure of the percentage of the system total area that is filled by the light of member galaxies. We concentrate in the comparison of our results with those of compact groups to assess how the triplets are a natural extension of these compact systems. Our analysis suggests that triplet galaxy members behave similarly to compact group members and galaxies in rich clusters. We also find that systems comprising three blue, star-forming, young stellar population galaxies (blue triplets) are most probably real systems and not a chance configuration of interloping galaxies. The same holds for triplets composed of three red, non-star-forming galaxies, showing the correlation of galaxy properties in these systems. From the analysis of the triplet as a whole, we conclude that, at a given total stellar mass content, triplets show a total star formation activity and global colours similar to compact groups. However, blue triplets show a high total star formation activity with a lower stellar mass content. From an analysis of the compactness parameter of the systems we find that light is even more concentrated in triplets than in compact groups. We propose that triplets composed of three luminous galaxies, should not be considered as an analogous of galaxy pairs with a third extra member, but rather they are a natural extension of compact groups.

Parallel Layout Construction Algorithm for Irregular Shape Packing Problems

Cutting and packing problems arise in a variety of industries, including garment, wood and shipbuilding. Irregular shape packing is a special case which admits irregular items and is much more complex due to the geometry of items. In order to ensure that items do not overlap and no item from the layout protrudes from the container, the collision free region concept was adopted. It represents all possible translations for a new item to be inserted into a container with already placed items. To construct a feasible layout, collision free region for each item is determined through a sequence of Boolean operations over polygons. In order to improve the speed of the algorithm, a parallel version of the layout construction was proposed and it was applied to a simulated annealing algorithm used to solve bin packing problems. Tests were performed in order to determine the speed improvement of the parallel version over the serial algorithm

A galaxy model from Two Micron All Sky Survey star counts in the whole sky, including the plane

We use the star count model of Ortiz & L´epine to perform an unprecedented exploration of the most important Galactic parameters comparing the predicted counts with the Two Micron All Sky Survey observed star counts in the J, H, and KS bands for a grid of positions covering the whole sky. The comparison is made using a grid of lines of sight given by the HEALPix pixelization scheme. The resulting best-fit values for the parameters are: 2120 ± 200 pc for the radial scale length and 205 ± 40 pc for the scale height of the thin disk, with a central hole of 2070+2000 −800 pc for the same disk, 3050 ± 500 pc for the radial scale length and 640 ± 70 pc for the scale height of the thick disk, 400 ± 100 pc for the central dimension of the spheroid, 0.0082 ± 0.0030 for the spheroid to disk density ratio, and 0.57 ± 0.05 for the oblate spheroid parameter.