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ARRAKIS: atlas of resonance rings as known in the S<sup>4</sup>G
Comeró,n, S.,Salo, H.,Laurikainen, E.,Knapen, J. H.,Buta, R. J.,Herrera-Endoqui, M.,Laine, J.,Holwerda, B. W.,Sheth, K.,Regan, M. W.,Hinz, J. L.,Muñ,oz-Mateos, J. C.,Gil de Paz, A.,Men&eac Springer-Verlag 2014 Astronomy and astrophysics Vol.562 No.-
<P>Context. Resonance rings and pseudorings (here collectively called rings) are thought to be related to the gathering of material near dynamical resonances caused by non-axisymmetries in galaxy discs. This means that they are the result of secular evolution processes that redistribute material and angular momentum in discs. Studying them may give clues on the formation and growth of bars and other disc non-axisymmetries. Aims. Our aims are to produce a catalogue and an atlas of the rings detected in the Spitzer Survey of Stellar Structure in Galaxies (S<SUP>4</SUP>G) and to conduct a statistical study of the data in the catalogue. Methods. We traced the contours of rings previously identified and fitted them with ellipses. We found the orientation of bars by studying the galaxy ellipse fits from the S<SUP>4</SUP>G pipeline 4. We used the galaxy orientation data obtained by the S<SUP>4</SUP>G pipeline 4 to obtain intrinsic ellipticities and orientations of rings and the bars. Results. ARRAKIS contains data on 724 ringed galaxies in the S<SUP>4</SUP>G. The frequency of resonance rings in the S<SUP>4</SUP>G is of 16 ±1% and 35 ±1% for outer and inner features, respectively. Outer rings are mostly found in Hubble stages −1 ≤T≤ 4. Inner rings are found in a broad distribution that covers the range −1 ≤T≤7. We confirm that outer rings have two preferred orientations, namely parallel and perpendicular to the bar. We confirm a tendency for inner rings to be oriented parallel to the bar, but we report the existence of a significant fraction (maybe as large as 50%) of inner features that have random orientations with respect to the bar. These misaligned inner rings are mostly found in late-type galaxies (T ≥4). We find that the fraction of barred galaxies hosting outer (inner) rings is ~1.7 times (~1.3 times) that in unbarred galaxies. Conclusions. We confirm several results from previous surveys as well as predictions from simulations of resonant rings and/or from manifold flux tube theory. We report that a significant fraction of inner rings in late-type galaxies have a random orientation with respect to the bar. This may be caused by spiral modes that are decoupled from the bar and dominate the Fourier amplitude spectrum at the radius of the inner ring. The fact that rings are only mildly favoured by bars suggests that those in unbarred galaxies either formed because of weak departures from the axisymmetry of the galactic potential or that they are born because of bars that were destroyed after the ring formation.</P>
A Neptune-mass Free-floating Planet Candidate Discovered by Microlensing Surveys
Mró,z, Przemek,Ryu, Y.-H.,Skowron, J.,Udalski, A.,Gould, A.,Szymań,ski, M. K.,Soszyń,ski, I.,Poleski, R.,Pietrukowicz, P.,Kozłowski, S.,Pawlak, M.,Ulaczyk, K.,Albrow, M. D.,Chung, S.-J American Astronomical Society 2018 The Astronomical journal Vol.155 No.3
THE THICK DISK IN THE GALAXY NGC 4244 FROM S<sup>4</sup>G IMAGING
Comeró,n, Sé,bastien,Knapen, Johan H.,Sheth, Kartik,Regan, Michael W.,Hinz, Joannah L.,Gil de Paz, Armando,Mené,ndez-Delmestre, Karí,n,Muñ,oz-Mateos, Juan-Carlos,Seibert, IOP Publishing 2011 The Astrophysical journal Vol.729 No.1
<P>If thick disks are ubiquitous and a natural product of disk galaxy formation and/or evolution processes, all undisturbed galaxies that have evolved during a significant fraction of a Hubble time should have a thick disk. The late-type spiral galaxy NGC 4244 has been reported as the only nearby edge-on galaxy without a confirmed thick disk. Using data from the Spitzer Survey of Stellar Structure in Galaxies (S(4)G) we have identified signs of two disk components in this galaxy. The asymmetries between the light profiles on both sides of the mid-plane of NGC 4244 can be explained by a combination of the galaxy not being perfectly edge-on and a certain degree of opacity of the thin disk. We argue that the subtlety of the thick disk is a consequence of either a limited secular evolution in NGC 4244, a small fraction of stellar material in the fragments which built the galaxy, or a high amount of gaseous accretion after the formation of the galaxy.</P>
Comeró,n, Sé,bastien,Elmegreen, Bruce G.,Knapen, Johan H.,Salo, Heikki,Laurikainen, Eija,Laine, Jarkko,Athanassoula, E.,Bosma, Albert,Sheth, Kartik,Regan, Michael W.,Hinz, Joannah L.,de Pa IOP Publishing 2011 The Astrophysical journal Vol.741 No.1
<P>Most, if not all, disk galaxies have a thin (classical) disk and a thick disk. In most models thick disks are thought to be a necessary consequence of the disk formation and/or evolution of the galaxy. We present the results of a study of the thick disk properties in a sample of carefully selected edge-on galaxies with types ranging from T = 3 to T = 8. We fitted one-dimensional luminosity profiles with physically motivated functions-the solutions of two stellar and one gaseous isothermal coupled disks in equilibrium-which are likely to yield more accurate results than other functions used in previous studies. The images used for the fits come from the Spitzer Survey of Stellar Structure in Galaxies (S(4)G). We found that thick disks are on average more massive than previously reported, mostly due to the selected fitting function. Typically, the thin and thick disks have similar masses. We also found that thick disks do not flare significantly within the observed range in galactocentric radii and that the ratio of thick-to-thin disk scale heights is higher for galaxies of earlier types. Our results tend to favor an in situ origin for most of the stars in the thick disk. In addition, the thick disk may contain a significant amount of stars coming from satellites accreted after the initial buildup of the galaxy and an extra fraction of stars coming from the secular heating of the thin disk by its own overdensities. Assigning thick disk light to the thin disk component may lead to an underestimate of the overall stellar mass in galaxies because of different mass-to-light ratios in the two disk components. On the basis of our new results, we estimate that disk stellar masses are between 10% and 50% higher than previously thought and we suggest that thick disks are a reservoir of 'local missing baryons.'</P>
Signatures of minor mergers in the Milky Way disc – I. The SEGUE stellar sample
Gó,mez, Facundo A.,Minchev, Ivan,O’Shea, Brian W.,Lee, Young Sun,Beers, Timothy C.,An, Deokkeun,Bullock, James S.,Purcell, Chris W.,Villalobos, Á,lvaro Blackwell Publishing Ltd 2012 Monthly notices of the Royal Astronomical Society Vol.423 No.4
<P><B>ABSTRACT</B></P><P>It is now known that minor mergers are capable of creating structure in the phase‐space distribution of their host galaxy’s disc. In order to search for such imprints in the Milky Way, we analyse the Sloan Extension for Galactic Understanding and Exploration (SEGUE) F/G dwarf and the Schuster et al. stellar samples. We find similar features in these two completely independent stellar samples, consistent with the predictions of a Milky Way minor‐merger event. We next apply the same analyses to high‐resolution, idealized <I>N</I>‐body simulations of the interaction between the Sagittarius dwarf galaxy and the Milky Way. The energy distributions of stellar particle samples in small spatial regions in the host disc reveal strong variations of structure with position. We find good matches to the observations for models with a mass of Sagittarius’ dark matter halo progenitor <IMG src='/wiley-blackwell_img/lap.gif' alt ='less-than or approximately equal-to'/>10<SUP>11</SUP> M<SUB>⊙</SUB>. Thus, we show that this kind of analysis could be used to provide unprecedentedly tight constraints on Sagittarius’ orbital parameters, as well as place a lower limit on its mass.</P>
Comeró,n, Sé,bastien,Elmegreen, Bruce G.,Salo, Heikki,Laurikainen, Eija,Athanassoula, E.,Bosma, Albert,Knapen, Johan H.,Gadotti, Dimitri A.,Sheth, Kartik,Hinz, Joannah L.,Regan, Michael W. IOP Publishing 2012 The Astrophysical journal Vol.759 No.2
<P>Breaks in the radial luminosity profiles of galaxies have until now been mostly studied averaged over disks. Here, we study separately breaks in thin and thick disks in 70 edge-on galaxies using imaging from the Spitzer Survey of Stellar Structure in Galaxies. We built luminosity profiles of the thin and thick disks parallel to midplanes and we found that thin disks often truncate (77%). Thick disks truncate less often (31%), but when they do, their break radius is comparable with that in the thin disk. This suggests either two different truncation mechanisms-one of dynamical origin affecting both disks simultaneously and another one only affecting the thin disk-or a single mechanism that creates a truncation in one disk or in both depending on some galaxy property. Thin disks apparently antitruncate in around 40% of galaxies. However, in many cases, these antitruncations are an artifact caused by the superposition of a thin disk and a thick disk, with the latter having a longer scale length. We estimate the real thin disk antitruncation fraction to be less than 15%. We found that the ratio of the thick and thin stellar disk mass is roughly constant (0.2 < M-T/M-t < 0.7) for circular velocities v(c) > 120 km s(-1), but becomes much larger at smaller velocities. We hypothesize that this is due to a combination of a high efficiency of supernova feedback and a slower dynamical evolution in lower-mass galaxies causing stellar thin disks to be younger and less massive than in higher-mass galaxies.</P>
Molecular Engineering of Zinc Phthalocyanines with Phosphinic Acid Anchoring Groups
Ló,pez‐,Duarte, Ismael,Wang, Mingkui,Humphry‐,Baker, Robin,Ince, Mine,Martí,nez‐,Dí,az, M. Victoria,Nazeeruddin, Mohammad K.,Torres, Tomá,s,Grä,tzel, Mich WILEY‐VCH Verlag 2012 Angewandte Chemie Vol.124 No.8
<P><B>Zwei Zinkphthalocyanin‐Photosensibilisatoren</B> mit verschiedenen Phosphinsäure‐Ankergruppen (siehe Schema) wurden synthetisiert. Solarzellen mit diesen Verbindungen verfügen über eine Photostromdichte von (7.6±0.2) mA cm<SUP>−2</SUP> bei geschlossenem Stromkreis, eine Spannung von (559±30) mV bei offenem Stromkreis und einen Füllfaktor von 0.76±0.03; dies entspricht einem Gesamtwirkungsgrad von 3.24 % unter 1 sun.</P>
Evolution of asexual and sexual reproduction in the aspergilli
Ojeda-Ló,pez, M.,Chen, W.,Eagle, C.E.,Gutié,rrez, G.,Jia, W.L.,Swilaiman, S.S.,Huang, Z.,Park, H.-S.,Yu, J.-H.,Cá,novas, D.,Dyer, P.S. CBS Fungal Biodiversity Centre 2018 Studies in mycology Vol.91 No.-
<P><I>Aspergillus nidulans</I> has long-been used as a model organism to gain insights into the genetic basis of asexual and sexual developmental processes both in other members of the genus <I>Aspergillus</I>, and filamentous fungi in general. Paradigms have been established concerning the regulatory mechanisms of conidial development. However, recent studies have shown considerable genome divergence in the fungal kingdom, questioning the general applicability of findings from <I>Aspergillus</I>, and certain longstanding evolutionary theories have been questioned. The phylogenetic distribution of key regulatory elements of asexual reproduction in <I>A. nidulans</I> was investigated in a broad taxonomic range of fungi. This revealed that some proteins were well conserved in the <I>Pezizomycotina</I> (<I>e.g.</I> AbaA, FlbA, FluG, NsdD, MedA, and some velvet proteins), suggesting similar developmental roles. However, other elements (<I>e.g.</I> BrlA) had a more restricted distribution solely in the <I>Eurotiomycetes</I>, and it appears that the genetic control of sporulation seems to be more complex in the aspergilli than in some other taxonomic groups of the <I>Pezizomycotina</I>. The evolution of the velvet protein family is discussed based on the history of expansion and contraction events in the early divergent fungi. Heterologous expression of the <I>A. nidulans abaA</I> gene in <I>Monascus ruber</I> failed to induce development of complete conidiophores as seen in the aspergilli, but did result in increased conidial production. The absence of many components of the asexual developmental pathway from members of the <I>Saccharomycotina</I> supports the hypothesis that differences in the complexity of their spore formation is due in part to the increased diversity of the sporulation machinery evident in the <I>Pezizomycotina</I>. Investigations were also made into the evolution of sex and sexuality in the aspergilli. <I>MAT</I> loci were identified from the heterothallic <I>Aspergillus</I> (<I>Emericella</I>) <I>heterothallicus</I> and <I>Aspergillus</I> (<I>Neosartorya</I>) <I>fennelliae</I> and the homothallic <I>Aspergillus pseudoglaucus</I> (=<I>Eurotium repens</I>). A consistent architecture of the <I>MAT</I> locus was seen in these and other heterothallic aspergilli whereas much variation was seen in the arrangement of <I>MAT</I> loci in homothallic aspergilli. This suggested that it is most likely that the common ancestor of the aspergilli exhibited a heterothallic breeding system. Finally, the supposed prevalence of asexuality in the aspergilli was examined. Investigations were made using <I>A. clavatus</I> as a representative ‘asexual’ species. It was possible to induce a sexual cycle in <I>A. clavatus</I> given the correct <I>MAT1-1</I> and <I>MAT1-2</I> partners and environmental conditions, with recombination confirmed utilising molecular markers. This indicated that sexual reproduction might be possible in many supposedly asexual aspergilli and beyond, providing general insights into the nature of asexuality in fungi.</P>