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To further our understanding of iron particle combustion, especially in the liquid state, in situ optical measurements are performed for the size evolution and temperature of laser-ignited iron particles in a narrow size range around 45-55μm. The particle size evolution is monitored by a high-speed shadowgraphy system, and the particle temperature is probed using a two-color pyrometer synchronized with the shadowgraphy system. Before a particle reaches the peak temperature, its diameter grows linearly with elapsed time. Near the peak temperature, three types of particle size behavior are detected, namely, smooth transition, micro-explosion, and rapid inflation. For particles with smooth transition, the size and temperature reach the maximum values at the same time, and thereafter the size remains constant, while the temperature drops until rapid solidification of the iron oxide droplet. The micro-explosion and rapid inflation clearly indicate towards a quick gas release inside the particle. The ambient oxygen concentration has a strong effect on the growth rate of the particle size before the peak temperature but no influence on the final particle size. The measured relative particle diameter at the peak temperature suggests that iron has been fully oxidized and the degree of oxidation could be higher than FeO. At the onset of solidification, gas release occurs again, resulting in a second inflation or burst of already inflated particles. This suggests that the oxygen dissolved in the liquid iron oxide is at least more than needed to form solid Fe3O4, and the solidification process is accompanied with gaseous oxygen release via the phase transition: L2 → Fe3O4(s) + O2(g) at 1855 K, where L2 represents liquid iron oxide with dissolved excess oxygen.

We study the rest-frame optical mass-size relation of bulges and discs from z similar to 2 to z similar to 0 for a complete sample of massive galaxies in the CANDELS fields using two-component Sersic models. Discs and star-forming galaxies follow similar mass-size relations. The mass-size relation of bulges is less steep than the one of quiescent galaxies (best-fitting slope of 0.7 for quiescent galaxies against 0.4 for bulges). We find little dependence of the structural properties of massive bulges and discs with the global morphology of galaxies (disc versus bulge dominated) and the star formation activity (star-forming versus quiescent). This result suggests similar bulge formation mechanisms for most massive galaxies and also that the formation of the bulge component does not significantly affect the disc structure. Our results pose a challenge to current cosmological models that predict distinct structural properties for stellar bulges arising from mergers and disc instabilities.

[Aims]: In this paper, we aim to study the main properties and luminosity function (LF) of the [O II]3727 emitters detected in the OTELO survey in order to characterise the star formation processes in low-mass galaxies at z ∼ 1.43 and to constrain the faint-end of the LF. [Methods]: Here, we describe the selection method and analysis of the emitters obtained from narrow-band scanning techniques. In addition, we present several relevant properties of the emitters and discuss the selection biases and uncertainties in the determination of the LF and the star formation rate density (SFRD). [Results]: We confirmed a total of 60 sources from a preliminary list of 332 candidates as [O II]3727 emitters. Approximately 93% of the emitters have masses in the range of 108, JAdD thanks the Instituto de Astrofísica de Canarias (IAC) for its support through the Programa de Excelencia Severo Ochoa and the Gobierno de Canarias for the Programa de Talento Tricontinental grant. This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under the grants AYA2013-46724-P, AYA2014-58861-C3-1-P, AYA2014-58861-C3-2-P, AYA2014-58861-C3-3-P, AYA2016-75808-R, AYA2016-75931-C2-1-P, AYA2016-75931-C2-2-P, and MDM-2017-0737 (Unidad de Excelencia María de Maeztu, CAB). This work was supported by the project Evolution of Galaxies, of reference AYA2017-88007-C3-1-P, within the “Programa estatal de fomento de la investigación científica y técnica de excelencia del Plan Estatal de Inves-tigación Científica y Técnica y de Innovación (2013–2016)” of the “Agencia Estatal de Investigación del Ministerio de Ciencia, Innovación y Universidades”, and co-financed by the FEDER “Fondo Europeo de Desarrollo Regional”. This article is based on observations made with the Gran Telescopio Canarias (GTC) at Roque de los Muchachos Observatory of the Instituto de Astrofísica de Canarias on the island of La Palma. This study makes use of data from AEGIS, a multi-wavelength sky survey conducted with the Chandra, GALEX, Hubble, Keck, CFHT, MMT, Subaru, Palomar, Spitzer, VLA, and other telescopes, and is supported in part by the NSF, NASA, and the STFC. Based on observations obtained with MegaPrime/MegaCam, a joint project of the CFHT and CEA/IRFU, at the Canada–France–Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l’Univers of the Centre National de la Recherche Sci-entifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at Terapix available at the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. Based on observations obtained with WIRCam, a joint project of CFHT, Taiwan, Korea, Canada, France, at the Canada–France–Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institute National des Sciences de l’Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX, the WIRDS (WIRcam Deep Survey) consortium, and the Canadian Astronomy Data Centre. This research was supported by a grant from the Agence Nationale de la Recherche ANR-07-BLAN-0228., With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (SEV-2017-0709).

We use the IllustrisTNG cosmological hydrodynamical simulations to investigate how the specific star formation rates (sSFRs) of massive galaxies $(M_* > 10^{10} M_\odot)$ depend on the distance to their closest companions. We estimate sSFR enhancements by comparing with control samples that are matched in redshift, stellar mass, local density and isolation, and we restrict our analysis to pairs with stellar mass ratios of 0.1 to 10. At small separations (~15 kpc), the mean sSFR is enhanced by a factor of 2.0 $\pm$ 0.1 in the flagship (110.7 Mpc)$^3$ simulation (TNG100-1). Statistically significant enhancements extend out to 3D separations of 280 kpc in the (302.6 Mpc)$^3$ simulation (TNG300-1). We find similar trends in the EAGLE and Illustris simulations, although their sSFR enhancements are lower than those in TNG100-1 by about a factor of two. Enhancements in IllustrisTNG galaxies are seen throughout the redshift range explored ($0 \leq z < 1$), with the strength of the enhancements decreasing with increasing redshift for galaxies with close companions. In order to more closely compare with observational results, we separately consider 2D projected distances between galaxies in IllustrisTNG. We detect significant sSFR enhancements out to projected separations of 260 kpc in TNG300-1, with projection effects diluting the size of the enhancements by about 20 per cent below 50 kpc. We find similar sSFR enhancements in TNG100-1 and Sloan Digital Sky Survey galaxies, with enhancements extending out to projected separations of about 150 kpc for star-forming galaxies at $z < 0.2$. Finally, by summing over all separations, we estimate that the presence of closest companions boosts the average sSFR of massive galaxies in TNG100-1 by 14.5 per cent., 19 pages, 13 figures. Accepted for publication in MNRAS

The island rule predicts that small animals evolve to become larger on islands, while large animals evolve to become smaller. It has been studied for over half a century, and its validity is fiercely debated. Here, we provide a perspective on the debate by conducting a test of the island rule in plants. Results from an extensive dataset on islands in the southwest Pacific illustrate that plant stature and leaf area obey the island rule, but seed size does not. Our results indicate that the island rule may be more pervasive than previously thought and that support for its predictions varies among functional traits.

We present a new sample of strong gravitational lens systems where both the foreground lenses and background sources are early-type galaxies. Using imaging from HST/ACS and Keck/NIRC2, we model the surface brightness distributions and show that the sources form a distinct population of massive, compact galaxies at redshifts $0.4 \lesssim z \lesssim 0.7$, lying systematically below the size-mass relation of the global elliptical galaxy population at those redshifts. These may therefore represent relics of high-redshift red nuggets or their partly-evolved descendants. We exploit the magnifying effect of lensing to investigate the structural properties, stellar masses and stellar populations of these objects with a view to understanding their evolution. We model these objects parametrically and find that they generally require two S\'ersic components to properly describe their light profiles, with one more spheroidal component alongside a more envelope-like component, which is slightly more extended though still compact. This is consistent with the hypothesis of the inside-out growth of these objects via minor mergers. We also find that the sources can be characterised by red-to-blue colour gradients as a function of radius which are stronger at low redshift -- indicative of ongoing accretion -- but that their environments generally appear consistent with that of the general elliptical galaxy population, contrary to recent suggestions that these objects are predominantly associated with clusters., Comment: 21 pages; accepted for publication in MNRAS

We study the rest-frame optical mass-size relation of bulges and discs from z similar to 2 to z similar to 0 for a complete sample of massive galaxies in the CANDELS fields using two-component Sersic models. Discs and star-forming galaxies follow similar mass-size relations. The mass-size relation of bulges is less steep than the one of quiescent galaxies (best-fitting slope of 0.7 for quiescent galaxies against 0.4 for bulges). We find little dependence of the structural properties of massive bulges and discs with the global morphology of galaxies (disc versus bulge dominated) and the star formation activity (star-forming versus quiescent). This result suggests similar bulge formation mechanisms for most massive galaxies and also that the formation of the bulge component does not significantly affect the disc structure. Our results pose a challenge to current cosmological models that predict distinct structural properties for stellar bulges arising from mergers and disc instabilities.

Controlling the size and shape of metallic colloids is crucial for a number of nanotechnological applications ranging from medical diagnosis to electronics. Yet, achieving tunability of morphological changes at the nanoscale is technically difficult and the structural modifications made on nanoparticles generally are irreversible. Here, we present a simple nonchemical method for controlling the size of metallic colloids in a reversible manner. Our strategy consists of applying hydrostatic pressure on a Ca cationic sublattice embedded in the irradiated matrix of CaF2 containing a large concentration of defects. Application of our method to CaF2 along with in situ optical absorption of the Ca plasmon shows that the radii of the Ca nanoparticles can be reduced with an almost constant rate of −1.2 nm/GPa up to a threshold pressure of ∼9.4 GPa. We demonstrate recovery of the original nanoparticles upon decompression of the irradiated matrix. The mechanisms for reversible nanocolloid-size variation are analyzed with first-principles simulations. We show that a pressure-driven increase in the binding energy between fluorine centers is responsible for the observed nanoparticle shrinkage. We argue that the same method can be used to generate other metallic colloids (Li, K, Sr, and Cs) with tailored dimensions by simply selecting an appropriate matrix., J.R.-F. and V.M. acknowledge the Spanish Ministry of Science, Innovation and Universities for the Juan de la Cierva program IJCI-2014-20513 and FJCI-2016-27921, respectively. C.C. acknowledges support from the Australian Research Council under the Future Fellowship funding scheme (No. FT140100135). Computational resources and technical assistance were provided by the Australian Government and the Government of Western Australia through the National Computational Infrastructure (NCI) and Magnus under the National Computational Merit Allocation Scheme and The Pawsey Supercomputing Centre. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 829161.

We analyse the Kormendy relations (KRs) of the two Frontier Fields clusters, Abell S1063, at z = 0.348, and MACS J1149.5+2223, at z = 0.542, exploiting very deep Hubble Space Telescope photometry and VLT/MUSE integral field spectroscopy. With this novel dataset, we are able to investigate how the KR parameters depend on the cluster galaxy sample selection and how this affects studies of galaxy evolution based on the KR. We define and compare four different galaxy samples according to: (a) S\'ersic indices: early-type ('ETG'), (b) visual inspection: 'ellipticals', (c) colours: 'red', (d) spectral properties: 'passive'. The classification is performed for a complete sample of galaxies with m$_{\textit{F814W}} \le$ 22.5 ABmag (M$_{*}$ $\gtrsim 10^{10.0}$ M$_{\odot}$). To derive robust galaxy structural parameters, we use two methods: (1) an iterative estimate of structural parameters using images of increasing size, in order to deal with closely separated galaxies and (2) different background estimations, to deal with the Intracluster light contamination. The comparison between the KRs obtained from the different samples suggests that the sample selection could affect the estimate of the best-fitting KR parameters. The KR built with ETGs is fully consistent with the one obtained for ellipticals and passive. On the other hand, the KR slope built on the red sample is only marginally consistent with those obtained with the other samples. We also release the photometric catalogue with structural parameters for the galaxies included in the present analysis., Comment: 23 pages, 18 figures, Accepted for publication in MNRAS

Caviomorph rodents are one of the most diverse mammalian groups in the Neotropics; they display astonishing eco-morphological variation, including unparalleled size range. Here we analyse evolutionary patterns among extant caviomorphs, particularly their rates of diversification and size evolution. The results show large heterogeneity in the evolutionary dynamics of caviomorphs. Three clear episodes of rapid increase of the diversification rate were detected; two of them during the Oligocene were related to the diversification of major clades; a third one, in the late Miocene, was related to the diversification of the genus Ctenomys. Regarding size, relatively low rates characterized much of Octodontoidea, the most speciose among the main caviomorph clades. Other clades, especially Cavioidea and Chinchilloidea, showed much accelerated evolutionary rates and the highest number of size changes, particularly increases; furthermore, they include extinct representatives that reached very large to gigantic size. Thus, although the macroevolutionary dynamics of caviomorphs were complex and heterogeneous in our study, the pathways followed by different clades seem to display their own particular characteristics. This should be analysed in greater depth through new, greater scale analyses incorporating the rich fossil record of caviomorphs, which contributes essential information to understand the evolution of these peculiar rodents., Facultad de Ciencias Naturales y Museo

The merging history of galaxies can be traced with studies of dynamically close pairs. These consist of a massive primary galaxy and a less massive secondary (or satellite) galaxy. The study of the stellar populations of secondary (lower mass) galaxies in close pairs provides a way to understand galaxy growth by mergers. Here we focus on systems involving at least one massive galaxy - with stellar mass above $10^{11}M_\odot$ in the highly complete GAMA survey. Our working sample comprises 2,692 satellite galaxy spectra (0.1, Comment: 14 pages, 11 figures, 2 tables, MNRAS, in press

We propose a simple model for the origin of fast and slow rotator early-type galaxies (ETG) within the hierarchical $\Lambda$CDM scenario, that is based on the assumption that the mass fraction of stellar discs in ETGs is a proxy for the specific angular momentum expressed via $\lambda_R$. Within our model we reproduce the fraction of fast and slow rotators as a function of magnitude in the \atl survey, assuming that fast rotating ETGs have at least 10% of their total stellar mass in a disc component. In agreement with \atl observations we find that slow rotators are predominantly galaxies with $ M_* > 10^{10.5}$ M$_{\odot}$ contributing $\sim 20%$ to the overall ETG population. We show in detail that the growth histories of fast and slow rotators are different, supporting the classification of ETGs into these two categories. Slow rotators accrete between $\sim 50% -90%$ of their stellar mass from satellites and their most massive progenitors have on average up to 3 major mergers during their evolution. Fast rotators in contrast, accrete less than 50% and have on average less than one major merger in their past. We find that the underlying physical reason for the different growth histories is the slowing down and ultimately complete shut-down of gas cooling in massive galaxies. Once cooling and associated star formation in disc stops, galaxies grow via infall from satellites. Frequent minor mergers thereby, destroy existing stellar discs via violent relaxation and also tend to lower the specific angular momentum of the main stellar body, lowering $\lambda_R$ into the slow rotator regime. Abridged..., Comment: Accepted for publication in MNRAS

We propose a simple model for the origin of fast and slow rotator early-type galaxies (ETG) within the hierarchical Lambda cold dark matter (Lambda CDM) scenario, that is based on the assumption that the mass fraction of stellar discs in ETGs is a proxy for the specific angular momentum expressed via lambda(R). Within our model we reproduce the fraction of fast and slow rotators as a function of magnitude in the ATLAS(3D) survey, assuming that fast-rotating ETGs have at least 10 per cent of their total stellar mass in a disc component. In agreement with ATLAS(3D) observations we find that slow rotators are predominantly galaxies with M-* > 10(10.5) M-circle dot contributing similar to 20 per cent to the overall ETG population. We show in detail that the growth histories of fast and slow rotators are different, supporting the classification of ETGs into these two categories. Slow rotators accrete between similar to 50 and 90 per cent of their stellar mass from satellites and their most massive progenitors have on average up to three major mergers during their evolution. Fast rotators in contrast accrete less than 50 per cent and have on average less than one major merger in their past.We find that the underlying physical reason for the different growth histories is the slowing down and ultimately complete shut-down of gas cooling in massive galaxies. Once cooling and associated star formation in disc stop, galaxies grow via infall from satellites. Frequent minor mergers thereby destroy existing stellar discs via violent relaxation and also tend to lower the specific angular momentum of the main stellar body, lowering lambda(R) into the slow rotator regime.On average, the last gas-rich major merger interaction in slow rotators happens at Z > 1.5, followed by a series of minor mergers. These results support the idea that kinematically decoupled cores (KDC) form during gas-rich major mergers at high Z followed by minor mergers, which build-up the outer layers of the remnant, and make remnants that are initially too flat compared to observations become rounder. Fast rotators are less likely to form such KDCs due to the fact that they have on average less than one major merger in their past. Fast rotators in our model have different formation paths. The majority, 78 per cent, has bulge-to-total stellar mass ratios (BIT) > 0.5 and managed to grow stellar discs due to continued gas cooling or bulges due to frequent minor mergers. The remaining 22 per cent live in high-density environments and consist of low BIT galaxies with gas fractions below 15 per cent, that have exhausted their cold gas reservoir and have no hot halo from which gas can cool. These fast rotators most likely resemble the flattened disc-like fast rotators in the ATLAS(3D) survey.Our results predict that ETGs can change their state from fast to slow rotator and vice versa, while the former is taking place predominantly at low z (z 10(10) M-circle dot) fast rotators being more than one order of magnitude more frequent at z similar to 2.

We combine high-resolution images in four optical/infrared bands, obtained with the laser guide star adaptive optics ( LGSAO) system on the Keck telescope and with the Hubble Space Telescope ( HST), to study the gravitational lens system SDSS J0737 + 3216 ( lens redshift 0.3223, source redshift 0.5812). We show that ( under favorable observing conditions) ground-based images are comparable to those obtained with HST in terms of precision in the determination of the parameters of both the lens mass distribution and the background source. We also quantify the systematic errors associated with both the incomplete knowledge of the PSF and the uncertain process of lens galaxy light removal and find that similar accuracy can be achieved with Keck LGSAO as with HST. We then exploit this well-calibrated combination of optical and gravitational telescopes to perform a multiwavelength study of the source galaxy at 0.01 '' effective resolution. We find the Sersic index to be indicative of a disklike object, but the measured half-light radius (r(e) = 0.59 +/- 0.007 stat +/- 0.1 sys kpc) and stellar mass (M* = 2.0 +/- 1.0 stat +/- 0.8 sys x 10(9) M(circle dot)) place it more than 3 sigma away from the local disk size-mass relation. The SDSS J0737 + 3216 source has the characteristics of the most compact faint blue galaxies studied and comparable size and mass to dwarf early-type galaxies in the local universe. With the aid of gravitational telescopes to measure individual objects' brightness profiles to 10% accuracy, the study of the high-redshift size-mass relation may be extended by an order of magnitude or more beyond existing surveys at the low-mass end, thus providing a new observational test of galaxy formation models.

We have analyzed the radial distribution of old stars in a sample of 218 nearby face-on disks, using deep 3.6 mu m images from the Spitzer Survey of Stellar Structure in Galaxies. In particular, we have studied the structural properties of those disks with a broken or down-bending profile. We find that, on average, disks with a genuine single-exponential profile have a scale length and a central surface brightness which are intermediate to those of the inner and outer components of a down-bending disk with the same total stellar mass. In the particular case of barred galaxies, the ratio between the break and the bar radii (R-br/R-bar) depends strongly on the total stellar mass of the galaxy. For galaxies more massive than 10(10) M-circle dot, the distribution is bimodal, peaking at R-br/R-bar similar to 2 and similar to 3.5. The first peak, which is the most populated one, is linked to the outer Lindblad resonance of the bar, whereas the second one is consistent with a dynamical coupling between the bar and the spiral pattern. For galaxies below 10(10) M-circle dot, breaks are found up to similar to 10 R-bar, but we show that they could still be caused by resonances given the rising nature of rotation curves in these low-mass disks. While not ruling out star formation thresholds, our results imply that radial stellar migration induced by non-axisymmetric features can be responsible not only for those breaks at similar to 2 R-bar, but also for many of those found at larger radii.

We use high-resolution K-band VLT/HAWK-I imaging over 0.25 square degrees to study the structural evolution of massive early-type galaxies since z~1. Mass-selected samples, complete down to log(M/M_sun)~10.7 such that `typical' L* galaxies are included at all redshifts, are drawn from pre-existing photometric redshift surveys. We then separated the samples into different redshift slices and classify them as late- or early-type galaxies on the basis of their specific star-formation rate. Axis-ratio measurements for the ~400 early-type galaxies in the redshift range 0.61 are, on average, flatter than at z11.3) are the roundest, with a pronounced lack among them of galaxies that are flat in projection. Merging is a plausible mechanism that can explain both results: at all epochs merging is required for early-type galaxies to grow beyond log(M/M_sun)~11.3, and all early types over time gradually and partially loose their disk-like characteristics., Comment: accepted for publication in ApJ; 11 pages; 10 figures; 4 tables

Evidence accumulated over the last decade has shown that allopolyploid genomes may undergo drastic reorganization. However, timing and mechanisms of structural diploidization over evolutionary timescales are still poorly known. As transposable elements (TEs) represent major and labile components of plant genomes, they likely play a pivotal role in fuelling genome changes leading to long-term diploidization. Here, we exploit the 4.5 MY old allopolyploid Nicotiana section Repandae to investigate the impact of TEs on the evolutionary dynamics of genomes. Sequence-specific amplified polymorphisms (SSAP) on seven TEs with expected contrasted dynamics were used to survey genome-wide TE insertion polymorphisms. Comparisons of TE insertions in the four allopolyploid species and descendents of the diploid species most closely related to their actual progenitors revealed that the polyploids showed considerable departure from predicted additivity of the diploids. Large numbers of new SSAP bands were observed in polyploids for two TEs, but restructuring for most TE families involved substantial loss of fragments relative to the genome of the diploid representing the paternal progenitor, which could be due to changes in allopolyploids, diploid progenitor lineages or both. The majority of non-additive bands were shared by all polyploid species, suggesting that significant restructuring occurred early after the allopolyploid event that gave rise to their common ancestor. Furthermore, several gains and losses of SSAP fragments were restricted to N. repanda, suggesting a unique evolutionary trajectory. This pattern of diploidization in TE genome fractions supports the hypothesis that TEs are central to long-term genome turnover and depends on both TE and the polyploid lineage considered.

We report the discovery of a massive ultra-compact quiescent galaxy that has been strongly-lensed into multiple images by a foreground galaxy at z = 0.960. This system was serendipitously discovered as a set of extremely Ks-bright high-redshift galaxies with red J - Ks colors using new data from the UltraVISTA YJHKs near-infrared survey. The system was also previously identified as an optically-faint lens/source system using the COSMOS ACS imaging by Faure et al. (2008, 2011). Photometric redshifts for the three brightest images of the source galaxy determined from twenty-seven band photometry place the source at z = 2.4 +/- 0.1. We provide an updated lens model for the system which is a good fit to the positions and morphologies of the galaxies in the ACS image. The lens model implies that the magnification of the three brightest images is a factor of 4 - 5. We use the lens model, combined with the Ks-band image to constrain the size and Sersic profile of the galaxy. The best-fit model is an ultra-compact galaxy (Re = 0.64^{+0.08}_{-0.18} kpc, lensing-corrected), with a Sersic profile that is intermediate between a disk and bulge profile (n = 2.2^{+2.3}_{-0.9}). We present aperture photometry for the source galaxy images which have been corrected for flux contamination from the central lens. The best-fit stellar population model is a massive galaxy (Log(M_{star}/M_{sol}) = 10.8^{+0.1}_{-0.1}, lensing-corrected) with an age of 1.0^{+1.0}_{-0.4} Gyr, moderate dust extinction (Av = 0.8^{+0.5}_{-0.6}), and a low specific star formation rate (Log(SSFR) < -11.0 yr^{-1}). This is typical of massive "red-and-dead" galaxies at this redshift and confirms that this source is the first bona fide strongly-lensed massive ultra-compact quiescent galaxy to be discovered. We conclude with a discussion of the prospects of finding a larger sample of these galaxies., 10 pages, 4 figures, 2 tables, accepted for publication in the ApJ

We have used high-resolution, Hubble Space Telescope, near-infrared imaging to conduct a detailed analysis of the morphological properties of the most massive galaxies at high redshift, modelling the WFC3/IR H-160-band images of the similar or equal to 200 galaxies in the CANDELS-UDS field with photometric redshifts 1 < z < 3, and stellar masses M-* > 10(11)M(circle dot). We have explored the results of fitting single-Sersic and bulge+disc models, and have investigated the additional errors and potential biases introduced by uncertainties in the background and the on-image point spread function. This approach has enabled us to obtain formally acceptable model fits to the WFC3/IR images of > 90 per cent of the galaxies. Our results indicate that these massive galaxies at 1 < z < 3 lie both on and below the local size-mass relation, with a median effective radius of similar to 2.6 kpc, a factor of similar or equal to 2.3 smaller than comparably massive local galaxies. Moreover, we find that bulge-dominated objects in particular show evidence for a growing bimodality in the size-mass relation with increasing redshift, and by z > 2 the compact bulges display effective radii a factor of similar or equal to 4 smaller than local ellipticals of comparable mass. These trends also appear to extend to the bulge components of disc-dominated galaxies. In addition, we find that, while such massive galaxies at low redshift are generally bulge-dominated, at redshifts 1 < z < 2 they are predominantly mixed bulge+disc systems, and by z > 2 they are mostly disc-dominated. The majority of the disc-dominated galaxies are actively forming stars, although this is also true for many of the bulge-dominated systems. Interestingly, however, while most of the quiescent galaxies are bulge-dominated, we find that a significant fraction (25-40 per cent) of the most quiescent galaxies, with specific star formation rates sSFR < 10(-10) yr(-1), have disc-dominated morphologies. Thus, while our results show that the massive galaxy population is undergoing dramatic changes at this crucial epoch, they also suggest that the physical mechanisms which quench star formation activity are not simply connected to those responsible for the morphological transformation of massive galaxies into present-day giant ellipticals.

Using data from the Sloan Digital Sky Survey (SDSS; data release 7), we have conducted a search for local analogs to the extremely compact, massive, quiescent galaxies that have been identified at z > 2. We show that incompleteness is a concern for such compact galaxies, particularly for low redshifts (z < ~0.05) as a result of the SDSS spectroscopic target selection algorithm. We have identified 63 massive red sequence galaxies at 0.066 < z < 0.12 that are smaller than the median size-mass relation by a factor of 2 or more. Consistent with expectations from the virial theorem, the median offset from the mass-velocity dispersion relation for these galaxies is 0.12 dex. We do not find any galaxies with sizes and masses comparable to those observed at z ~ 2, implying a decrease in the comoving number density (at fixed size and mass) by a factor of > 5000. This result cannot be explained by incompleteness: at 0.066 < z, Submitted to ApJ: 18 pages in emulateapj format, 11 figures. Table of galaxy properties available on line from http://www.strw.leidenuniv.nl/~ent/

A single crystal plasticity theory for insertion into finite element simulation is formulated using sequential laminates to model subgrain dislocation structures. It is known that local models do not adequately account for latent hardening, as latent hardening is not only a material property, but a nonlocal property (e.g., grain size and shape). The addition of the nonlocal energy from the formation of subgrain structure dislocation walls and the boundary layer misfits provide both latent and self hardening of crystal slip. Latent hardening occurs as the formation of new dislocation walls limit motion of new mobile dislocations, thus hardening future slip systems. Self hardening is accomplished by evolution of the subgrain structure length scale. No multiple slip hardening terms are included. The substructure length scale is computed by minimizing the nonlocal energy. The minimization of the nonlocal energy is a competition between the dislocation wall and boundary layer energy. The nonlocal terms are also directly minimized within the subgrain model as they impact deformation response. The geometrical relationship between the dislocation walls and slip planes affecting dislocation mean free path is accounted for giving a first-order approximation to shape effects. A coplanar slip model is developed due to requirements when modeling the subgrain structure. This subgrain structure plasticity model is noteworthy as all material parameters are experimentally determined rather than fit. The model also has an inherit path dependency due to the formation of the subgrain structures. Validation is accomplished by comparison to single crystal tension test results.

We combine high-resolution images in four optical/infrared bands, obtained with the laser guide star adaptive optics ( LGSAO) system on the Keck telescope and with the Hubble Space Telescope ( HST), to study the gravitational lens system SDSS J0737 + 3216 ( lens redshift 0.3223, source redshift 0.5812). We show that ( under favorable observing conditions) ground-based images are comparable to those obtained with HST in terms of precision in the determination of the parameters of both the lens mass distribution and the background source. We also quantify the systematic errors associated with both the incomplete knowledge of the PSF and the uncertain process of lens galaxy light removal and find that similar accuracy can be achieved with Keck LGSAO as with HST. We then exploit this well-calibrated combination of optical and gravitational telescopes to perform a multiwavelength study of the source galaxy at 0.01 '' effective resolution. We find the Sersic index to be indicative of a disklike object, but the measured half-light radius (r(e) = 0.59 +/- 0.007 stat +/- 0.1 sys kpc) and stellar mass (M* = 2.0 +/- 1.0 stat +/- 0.8 sys x 10(9) M(circle dot)) place it more than 3 sigma away from the local disk size-mass relation. The SDSS J0737 + 3216 source has the characteristics of the most compact faint blue galaxies studied and comparable size and mass to dwarf early-type galaxies in the local universe. With the aid of gravitational telescopes to measure individual objects' brightness profiles to 10% accuracy, the study of the high-redshift size-mass relation may be extended by an order of magnitude or more beyond existing surveys at the low-mass end, thus providing a new observational test of galaxy formation models.