bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructure and Mechanical Properties of Ti Cold-Spray Splats Determined by Electron Channeling Contrast Imaging and Nanoindentation Mapping
Authors: Goldbaum Dina , Chromik Richard R. , Brodusch Nicolas , Gauvin Raynald
Published: March 2015

Cold spray is a thermo-mechanical process where the velocity of the sprayed particles affects the deformation, bonding, and mechanical properties of the deposited material, in the form of splats or coatings. At high strain rates, the impact stresses are converted into heat, a phenomenon known as adiabatic shear, which leads to grain re-crystallization. Grain re-crystallization and growth are shown to have a direct impact on the mechanical properties of the cold-sprayed material. The present study ties the microstructural features within the cold-sprayed Ti splats and the substrate to the bonding mechanism and mechanical properties. High-resolution electron channeling contrast imaging, electron backscatter diffraction mapping, and nanoindentation were used to correlate the microstructure to the mechanical properties distribution within the titanium cold-spray splats. The formation of nanograins was observed at the titanium splat/substrate interface and contributed to metallurgical bonding. An increase in grain re-crystallization within the splat and substrate materials was observed with pre-heating of the substrate. In the substrate material, the predominant mechanism of deformation was twinning. A good relationship was found between the hardness and distribution of the twins within the substrate and the size distribution of the re-crystallized grains within the splats.
Very Massive Stars in the local Universe
Authors: Vink Jorick S. , Heger Alexander , Krumholz Mark R. , Puls Joachim , Banerjee S. , Castro N. , Chen K.-J. , Chenè A.-N. , Crowther P. A. , Daminelli A. , Gräfener G. , Groh J. H. , Hamann W.-R. , Heap S. , Herrero A. , Kaper L. , Najarro F. , Oskinova L. M. , Roman-Lopes A. , Rosen A. , Sander A. , Shirazi M. , Sugawara Y. , Tramper F. , Vanbeveren D. , Voss R. , Wofford A. , Zhang Y. ,   the participants of JD2
Published: March 2015

Recent studies have claimed the existence of very massive stars (VMS) up to 300M⊙in the local Universe. As this finding may represent a paradigm shift for the canonical stellar upper-mass limit of 150M⊙, it is timely to discuss the status of the data, as well as the far-reaching implications of such objects. We held a Joint Discussion at the General Assembly in Beijing to discuss (i) the determination of the current masses of the most massive stars, (ii) the formation of VMS, (iii) their mass loss, and (iv) their evolution and final fate. The prime aim was to reach broad consensus between observers and theorists on how to identify and quantify the dominant physical processes.
Evolution of Stellar Magnetic Fields
Authors: Güdel Manuel
Published: March 2015

Stellar magnetic fields can reliably be characterized by several magnetic activity indicators, such as X-ray or radio luminosity. Physical processes leading to such emission provide important information on dynamic processes in stellar atmospheres and magnetic structuring.
Microflares to megaflares: Solar observations and modeling
Authors: Fletcher Lyndsay
Published: March 2015

The observationally determined properties of solar flares such as overall energy budget and distribution in space, time and energy of flare radiation, have improved enormously over the last cycle. This has enabled precision diagnostics of flare plasmas and nonthermal particles in large and small events, informing and driving new theoretical models. The theoretical challenges in understanding flare are considerable, involving MHD and kinetic processes operating in an environment far from equilibrium. New observations have also provided some challenges to long-standing models of flare energy release and transport. This talk overviewed recent observational and theoretical developments, and highlighted some important questions for the future
The UV-upturn in brightest cluster galaxies
Authors: Loubser S. I. , Sánchez-Blázquez P.
Published: March 2015

This study is part of a series devoted to the investigation of a large sample of brightest cluster galaxies (BCGs), their properties and the relationships between these and the properties of the host clusters. In this paper, we compare the stellar population properties derived from high signal-to-noise, optical long-slit spectra with the GALEX ultraviolet (UV) colour measurements for 36 nearby BCGs to understand the diversity in the most rapidly evolving feature in old stellar systems, the UV-upturn. We investigate: (1) the possible differences between the UV-upturn of BCGs and those of a control sample of ordinary ellipticals in the same mass range, as well as possible correlations between the UV-upturn and other general properties of the galaxies; (2) possible correlations between the UV-upturn and the properties of the host clusters; (3) recently proposed scenarios where helium-sedimentation in the cluster centre can produce an enhanced UV-upturn. We find systematic differences between the UV-colours of BCGs and ordinary ellipticals, but we do not find correlations between these colours and the properties of the host clusters. Furthermore, the observations do not support the predictions made by the helium-sedimentation model as an enhancer of the UV-upturn.
Correlation of morphological fraction with redshift in galaxy clusters
Authors: Yuan Qi-Rong , Dang Qiang-Qiang , Yan Peng-Fei , Chen Wei , Wen Zhong-Lue , Han Jin-Lin , Zhou Xu
Published: March 2015

Based on 187 galaxy clusters identified from the photometric redshifts of galaxies in the Cosmic Evolution Survey (COSMOS) field(Wen & Han 2011), cluster galaxies brighter than MV = -20.5 are classified into four categories according to their best-fitting templates of the spectral energy distributions (SEDs) provided by Ilbert et al. (2009): early-type (including elliptical and lenticular) galaxies (E+S0), spiral galaxies (S), irregular galaxies (Irr), and starbursts (SB). The fractions of these four SED types are presented as the functions of redshift in Figure 1. Fraction of each category varies remarkably with cluster redshift: fractions of normal galaxies (E+S0+S+Irr) tend to decrease with redshift, whilst the starburst proportion tends to increase with redshift. For the normal galaxies, there exists a sequence for the decreasing slopes of morphological fractions. Majority of the galaxies in high-redshift clusters (z > 1.0) are experiencing strong star-formation activities, which leads to a very high proportion of starburst.
Meteorites – The Significance of Collection and Curation and Future Developments
Authors: Smith Caroline
Published: March 2015

Meteorites are some of the most important and valuable rocks available for scientific study. Approximately 43,000 meteorites are known on Earth and are egeologicalf samples of extraterrestrial bodies - meteorites are known to originate from asteroids, the Moon, Mars and possibly comets. With expanding exploration of our Solar System, meteorites provide the eground truthf to compare data collected by robotic missions with results gained from a variety of more accurate and precise techniques using laboratories on Earth. This talk will give an introduction to the history of meteorite science and the importance of meteorite collections to the field of meteoritics, planetary and solar system science. Curation of extraterrestrial samples is a particularly pertinent issue, especially with regards to particularly rare samples such as those from Mars like the recent Tissint meteorite. Future sample return missions to asteroids and Mars also pose siginificant challenges around the curation of these precious materials. Issues surrounding the curation of samples and how curation and curatorial actions can influence scientific studies will also be discussed.
A list of historical comets observed at plural sites: the beginning of astronomy in Japan and Korea
Authors: Tanikawa Kiyotaka , Sôma Mitsuru
Published: March 2015

Comets generally stay long in the sky and can be seen from many places on the surface of the Earth. We are interested in historical comets which were observed at plural sites. We have shown in a previous work (Tanikawa & Sôma, 2008) that in the seventh century, five comets were observed independently in China and Japan. From this fact and other data, we deduced that Japanese observational astronomy started in the seventh century. We know that, other than China and Japan, Korea and Vietnam had observational astronomy before the 9th century. We look for historical comets observed at plural sites by surveying the existing literature of respective countries. Examining the independence of the records, we provide a list of comets observed independently at plural sites. This strengthens the reliability of the records of comets. The list can be used for other purposes.
Disk-Resolved Spectra of (25143) Itokawa with Hayabusa/AMICA observations
Authors: Ishiguro Masateru
Published: March 2015

We introduce a new data reduction method for Hayabusa/AMICA data to subtract a scattered light inside the optics. As the result, we obtained a map of space weathering on Itokawa for all available channels.
Supplemental ancient Chinese meteor, meteorite fall and comet records with Zhongguo gudai tianxiang jilu zongji (1)
Authors: Nagatoshi Nogami
Published: March 2015

Zhongguo guidai tianxiang jilu zongji pressed in 1988 containes ancient Chinese astronomical records including that of meteor, meteorite fall and comet until 1911 from the Standard Histories and local gazetteers existed in China. On the other hand, many local gazetteers lost in China at present have been collected in university and public libraries in Japan. Especially the library of Chinese section in the Research Institute for Humanistic Studies in Kyoto University and the Oriental Library in Tokyo have big collection. This presentation will give a few dozens supplemential ancient records with that big book from local gazetteers in above mentioned libraries.
Spectrophotometric properties of Moon's and Mars's surfaces exploration by shadow mechanism
Authors: Morozhenko Alexandr , Vidmachenko Anatolij , Kostogryz Nadiia
Published: March 2015

Typically, to analyze the data of the phase dependence of brightness atmosphereless celestial bodies one use some modification of the shadow mechanism involving the coherent mechanism. There are several modification of B.Hapke [2] model divided into two groups by the number of unknown parameters: the first one with 4 parameters [3,4] and the second one with up to 10 unknown parameters [1] providing a good agreement of observations and calculations in several wavelengths. However, they are complicated by analysing of the colorindex C(α) dependence and photometric contrast of details with phase K(α) and on the disk (μ o = cos i). We have got good agreement between observed and calculated values of C(α) = U(α)-I(α), K(α), K(muo) for Moon and Mars with a minimum number of unknown parameters [4]. We used an empirical dependence of single scattering albedo (ω) and particle semi-transparency(æ): æ = (1-ω)n. Assuming that [χ (0°)/χ(5°)] = χ (5°)/χ (0°)], where χ(α) is scattering function, using the phase dependence of brightness and opposition effect in a single wavelength, we have defined ω,χ(α),g (particle packing factor), and the first term expansion of χ(α) in a series of Legendre polynomials x1. Good agreement between calculated and observed data of C(α) = U(α)-I(α) for the light and dark parts of the lunar surface and the integral disk reached at n ≈ 0,25, g = 0,4 (porosity 0,91), x1 = -0,93, ω = 0,137 at λ = 359nm and 0,394 at λ = 1064nm;, for Mars with n ≈ 0,25,g = 0,6 (porosity 0,84), x1 ≈ 0, ω = 0,210 at λ = 359nm and ω = 0,784 at λ = 730nm.

1. Bowell E., Hapke B., Domingue D., Lumme K., et al. Applications of photometric models to asteroids, in Asteroids II. Tucson: Univ. Arizona Press. p.524-556. (1989)

2. Hapke B. A theoretical function for the lunar surface, J.Geophys.Res. 68, No.15., 4571-4586(1963).

3. Irwine W. M., The shadowing effect in diffuse reflection, J.Geophys.Res. 71,No.12, 2931-2937(1966).

4. Morozhenko A. V., Yanovitskij E.G., An optical model of the Martian surface in the visible region of spectrum, Astronomy Reports 48, No.4, 795-809(1971).
SOFA—an IAU service fit for the future
Authors: Hohenkerk C.
Published: March 2015

Standards of Fundamental Astronomy (SOFA) is an International Astronomical Union (IAU) service that provides accessible and authoritative algorithms and procedures that implement standard models used in fundamental astronomy. This paper summaries the current status, noting the changes during 2009-2012, and discusses issues that may arise in the future.
Multiple Sequences of M-dwarfs in NGC 2808 and ω Centauri.
Authors: Milone A. P.
Published: March 2015

The infrared channel of the Wide-Field Camera 3 on the Hubble Space Telescope revealed multiple main sequences of very low-mass stars in the globular clusters NGC 2808 and ω Cen. In this paper I summarize the observational facts and provide a possible interpretation.
Rapid Mass Segregation in Massive Star Clusters
Authors: McMillan Stephen , Vesperini Enrico , Kruczek Nicholas
Published: March 2015

Several dynamical scenarios have been proposed that can lead to prompt mass segregation on the crossing time scale of a young cluster. They generally rely on cool and/or clumpy initial conditions, and are most relevant to small systems. As a counterpoint, we present a novel dynamical mechanism that can operate in relatively large, homogeneous, cool or cold systems. This mechanism may be important in understanding the assembly of large mass-segregated clusters from smaller clumps.
Nuclear Star Clusters Structure and Stellar Populations
Authors: Neumayer Nadine
Published: March 2015

This is an overview of nuclear star cluster observations, covering their structure, stellar populations, kinematics and possible connection to black holes at the centers of galaxies.
Galactic rings and secular evolution in barred galaxies
Authors: Knapen Johan H.
Published: March 2015

Rings are common in galaxies. Several kinds of rings are known: collisional, polar, and resonance rings, of which the latter is by far most common. Resonance rings are prime tracers of the underlying dynamical structure of disk galaxies, in particular of orbital resonances and of manifolds. Rings are also indicators of angular momentum transport, and this is a key factor in secular evolution (see the various reviews in Falcón-Barroso & Knapen 2012).

Resonance rings come in three flavours, primarily defined by their size, namely nuclear, inner, and outer rings. From studies like those of Buta (1995), Knapen (2005) and Comerón et al. (2010, 2013) we know that the radii of nuclear rings range from a few tens of parsec to some 3.5 kpc, while inner rings and outer rings have typical radii of 1.2 and 2.5–3 times the length of the bar. Many host galaxies of rings are barred, but so are most galaxies in general. Some 20% of all rings occur in non-barred galaxies, which implies that rings do not, or hardly, occur preferentially in barred galaxies (Knapen 2005, Comerón et al. 2010, 2013). In most non-barred ringed galaxies an oval, a past interaction, or even a prominent spiral pattern lies at the dynamical origin of the ring, but this needs additional scrutiny.

From an inventory of all known nuclear rings, Comerón et al. (2010) reach the following conclusions. Star-forming nuclear rings occur in 20 ± 2% of disk galaxies with −3 < T < 7; 18/96 occur in disk galaxies without a bar (19%); they are found in S0 to Sd galaxies, peaking in types Sab Sb; when nuclear rings occur in barred galaxies, the ring radius is limited to one quarter of the bar radius; and stronger bars host smaller rings (cf. Knapen 2005).

We are now using the Spitzer Survey of Spiral Structure in Galaxies (S4G; Sheth et al. 2010) to expand our survey to inner and outer rings (Comerón et al. 2013). We aim to study the relations between ring and host properties – as we did before for nuclear rings. We will use the S4G sample size and image depth to reach further insight into the secular evolution of galaxies by measuring structural properties of rings, as well as those of components like bars and disks. We will then be able to tackle outstanding questions such as the origin of rings in non-barred galaxies, and how exactly ring properties are determined by the bar.
Rejuvenation of bulges by bars: evidence from stellar population analysis
Authors: Gadotti Dimitri A. , Coelho Paula
Published: March 2015

We obtained stellar ages and metallicities via spectrum fitting for a sample of 575 bulges with spectra available from the SDSS. Using the whole sample, where galaxy stellar mass distributions for barred and unbarred galaxies are similar, we find that the distribution of bulge ages in barred galaxies shows an excess of populations younger than 4 Gyr, when compared to bulges in unbarred galaxies. KS statistics confirm that the age distributions are different with a significance of 99.94%. If we select sub-samples for which the bulge stellar mass distributions are similar for barred and unbarred galaxies, this excess vanishes for galaxies with low-mass bulges, while for more massive bulges we find a bimodal stellar age distribution for barred galaxies only, corresponding to two normal distributions with mean ages of 10.4 and 4.7 Gyr (see Fig. 1). These results lend strong support to models in which bars trigger star formation activity in the centers of galaxies. We also find twice as much AGN among barred galaxies, as compared to unbarred galaxies, for low-mass bulges. Full results are in Coelho & Gadotti (2011).
The downplayed role of secular processes in the co-evolution of galaxies and black holes
Authors: Cisternas Mauricio , Jahnke Knud
Published: March 2015

According to the current co-evolution picture, most present-day galaxies experienced at least one phase of vigorous black hole (BH) activity in the past, during which a tight link between galaxy and BH gets established. While during the last two decades we have witnessed tremendous progress in the field, additional robust observational constraints are required on how galaxy and BH related at earlier times, and which mechanisms are responsible for triggering these BH growth phases. In our recent studies, we analyzed a large sample of active galactic nuclei (AGN) out to z ~ 1 from the COSMOS survey (Scoville et al. 2007), allowing us to study in detail growing BHs together with their host galaxies. In Cisternas et al. (2011b) we found that, for a sample of 32 active galaxies at z ~ 0.7, BH mass scales with total galaxy stellar mass in the same way as it does locally, at z = 0, with galactic bulge mass. I will argue that for these galaxies to obey the local relation only a disk-to-bulge stellar mass redistribution is needed, likely driven by passive secular evolution. I will also present the results from Cisternas et al. (2011a), aiming to understand the relevance of major mergers as AGN activity triggering mechanisms. By looking for merging signatures on the morphologies of 140 AGN (some examples shown in Figure 1), and comparing them with a sample of over 1200 matched inactive galaxies, we found that the merger fraction between samples is statistically the same, at roughly 15%. Together with the fact that the majority of the AGN host galaxies are disk-dominated, unlikely relics of a recent major merger, these results are the strongest evidence to date that secular evolution rather than major merging has dominated BH fueling at least since z ~ 1.
Chemical fingerprinting of stellar populations in the Milky Way halo
Authors: Chou Mei-Yin
Published: March 2015

The idea of “chemically fingerprinting“ stars to their birth systems has been discussed over the last decade. Here we present an investigation of the chemical abundance patterns of halo substructures using high-resolution spectra. In particular, we study the abundances of the α-like element titanium (Ti) and the s-process elements yttrium (Y) and lanthanum (La) for M giant candidates of the Galactic Anticenter Stellar Structure (GASS, also known as the Monoceros Ring) and the Triangulum-Andromeda (TriAnd) Star Cloud. We apply “chemical fingerprinting“ to the GASS/Monoceros Ring and TriAnd Star Cloud, to explore the origins of the two systems and the hypothesized connections between them. GASS has been debated either to originate from a part (e.g., warp) of the Galactic disk or tidal debris of a disrupted Milky Way (MW) satellite galaxy. Our exploration shows that GASS is indeed made of stars from a dwarf spheroidal (dSph) galaxy, although we still can not rule out the possibility that GASS was dynamically created out of a previously formed outer MW disk. And whereas the TriAnd Star Cloud has been assumed to come from the tidal disruption of the same accreted MW satellite as the GASS/Monoceros Ring, our comparison of the abundance patterns in GASS and TriAnd M giants suggests that the TriAnd Star Cloud is likely an independent halo substructure unrelated to the GASS/Monoceros Ring. Furthermore, our findings also suggest that the MW may have accreted other satellites in addition to the on-going, well-known Sagittarius (Sgr) dwarf galaxy.
The outskirts of spiral galaxies: probing stellar migration theory
Authors: Bakos Judit , Trujillo Ignacio
Published: March 2015

One of the most outstanding predictions of the radial migration theory was a progressive increase in the age of the stellar populations toward the galaxy outskirts. This gradual change in the age is caused by a net flux of old stars formed in the inner disk moving toward the outskirts. Thanks to the fact that the age of stellar populations can be interpreted in terms of colors, this prediction was confirmed observationally a few years ago with deep surface brightness profiles of a large sample of nearby galaxies. Our group has now taken a step forward on this as we have explored the properties of the stellar populations beyond the star formation threshold using ultra deep data from SDSS Stripe82. These data allowed us to study the faint outskirts of disks in detail down to a surface brightness level of 30 mag/arcsec2 in the r'-band. At these surface brightness levels spiral galaxies reveal new and exciting structural components which could not have been seen by regular SDSS imaging: outer disks extend farther out, tidal streams and satellites become visible. We will present deep color profiles of the regions of the galaxies where the disks starts to be confused with the stellar haloes. We confront these colors with model predictions. For some galaxies, the very outer regions are so red that conventional IMFs can not explain their colors. We will discuss whether our new results can be explained within the radial migration scheme.
A test for radial mixing using local star samples
Authors: Yu Jincheng , Sellwood Jerry , Pryor Carlton , Chen Li , Hou Jinliang
Published: March 2015

We use samples of local main-sequence stars to show that the radial gradient of [Fe/H] in the thin disk of the Milky Way decreases with mean effective stellar temperature. We use the angular momentum of each star about the Galactic center to eliminate the effects of epicyclic motion, which would otherwise blur the estimated gradients. We use the effective temperatures as a proxy for mean age, and conclude that the decreasing gradient is consistent with the predictions of radial mixing due to transient spiral patterns. We find some evidence that the trend of decreasing gradient with increasing mean age breaks to a constant gradient for samples of stars whose main-sequence life-times exceed the likely age of the thin disk.
Quantifying secular evolution through structural decomposition
Authors: Kelvin Lee
Published: March 2015

Structure within a galaxy is not random, instead emerging as a direct function of its evolutionary path. It is thought that secular evolutionary processes leave behind distinct structural tracers in the form of bars, pseudo-bulges and rings. We have developed a robust automated structural analysis pipeline (Kelvin et al., 2012) able to accurately map structure across a range of ground and space-based datasets. Using reprocessed SDSS and UKIDSS data from the GAMA survey: an imaging and spectroscopic survey with over 300,000 redshifts across 300 square degrees (Driver et al., 2009); we measure the relative abundance and stellar mass locked up within these structures in the local (z<0.06) Universe. Future robust calculations of the stellar mass budget within bulges, bars, disks and pseudo-bulges should allow us to measure the relative importance of secular evolution against other mechanisms across cosmic time.
Galaxies driven only by secular evolution?
Authors: Verdes-Montenegro Lourdes ,   on behalf of the AMIGA team
Published: March 2015

The AMIGA project (Analysis of the interstellar Medium of Isolated GAlaxies, http://amiga.iaa.es) has identified a significant sample of very isolated (Tcc(nearest-neighbor) ≈2-3Gyr) galaxies in the local Universe and revealed that they have different properties than galaxies in richer environments. Our analysis of a multiwavelength database includes quantification of degree of isolation, morphologies, as well as FIR and radio line/continuum properties.

Properties usually regarded as susceptible to interaction enhancement show lower averages in AMIGA–lower than any galaxy sample yet identified. We find lower MIR/FIR measures (Lisenfeld et al. 2007), low levels of radio continuum emission (Leon et al. 2008), no radioexcess above the radioFIR correlation (0%, Sabater et al.2008), a small number of AGN (22%, Sabater et al. 2012), and lower molecular gas content (Lisenfeld et al. 2011). The late-type spiral majority in our sample show very small bulge/total ratios (largely <0.1) and Sersic indices consistent with an absence of classical bulges (Durbala et al. 2008). They show redder g-r colors and lower color dispersion for AMIGA subtypes (Fernandez-Lorenzo et al. 2012) and show the narrowest (gaussian) distribution of HI profile asymmetries of any sample yet studied.

This work has been supported by Grant AYA2011-30491-C02-01 co-financed by MICINN and FEDER funds, and the Junta de Andalucia (Spain) grants P08-FQM-4205 and TIC-114.
Hoag's object: the quintessential ring galaxy
Authors: Brosch Noah , Finkelman Ido , Moiseev Alexei
Published: March 2015

We present new observations of Hoag's Object, known as “the most perfect ring galaxy,“ that show that a preferred explanation for this object is (a) the formation of a triaxial elliptical galaxy some 10 Gyr ago, (b) the accretion of a large disk of neutral hydrogen at about the same time, (c) low-level star formation in the HI disk for all the time since that event triggered by the triaxial potential of the core.
Shaping Disk Galaxy Stellar Populations via Internal and External Processes
Authors: Roškar Rok
Published: March 2015

In recent years, effects such as the radial migration of stars in disks have been recognized as important drivers of the properties of stellar populations. Radial migration arises due to perturbative effects of disk structures such as bars and spiral arms, and can deposit stars formed in disks to regions far from their birthplaces. Migrant stars can significantly affect the demographics of their new locales, especially in low-density regions such as in the outer disks. However, in the cosmological environment, other effects such as mergers and filamentary gas accretion also influence the disk formation process. Understanding the relative importance of these processes on the detailed evolution of stellar population signatures is crucial for reconstructing the history of the Milky Way and other nearby galaxies. In the Milky Way disk in particular, the formation of the thickened component has recently attracted much attention due to its potential to serve as a diagnostic of the galaxy's early history. Some recent work suggests, however, that the vertical structure of Milky Way stellar populations is consistent with models that build up the thickened component through migration. I discuss these developments in the context of cosmological galaxy formation.
Magnetic fields in spiral galaxies
Authors: Krause Marita
Published: March 2015

The magnetic field structure in edge-on galaxies observed so far shows a plane-parallel magnetic field component in the disk of the galaxy and an X-shaped field in its halo. The plane-parallel field is thought to be the projected axisymmetric (ASS) disk field as observed in face-on galaxies. Some galaxies addionionally exhibit strong vertical magnetic fields in the halo right above and below the central region of the disk. The mean-field dynamo theory in the disk cannot explain these observed fields without the action of a wind, which also probably plays an important role to keep the vertical scale heights constant in galaxies of different Hubble types and star formation activities, as has been observed in the radio continuum: At λ6 cm the vertical scale heights of the thin disk and the thick disk/halo in a sample of five edge-on galaxies are similar with a mean value of 300 ± 50 pc for the thin disk and 1.8 ± 0.2 kpc for the thick disk (a table and references are given in Krause 2011) with our sample including the brightest halo observed so far, NGC 253, with strong star formation, as well as one of the weakest halos, NGC 4565, with weak star formation. If synchrotron emission is the dominant loss process of the relativistic electrons the outer shape of the radio emission should be dumbbell-like as has been observed in several edge-on galaxies like e.g. NGC 253 (Heesen et al. 2009) and NGC 4565. As the synchrotron lifetime tsyn at a single frequency is proportional to the total magnetic field strength Bt−1.5, a cosmic ray bulk speed (velocity of a galactic wind) can be defined as vCR = hCR/tsyn = 2 hz/tsyn, where hCR and hz are the scale heights of the cosmic rays and the observed radio emission at this freqnency. Similar observed radio scale heights imply a self regulation mechanism between the galactic wind velocity, the total magnetic field strength and the star formation rate SFR in the disk: vCR∝ Bt1.5 ∝ SFR≈ 0.5 (Niklas & Beck 1997).
RM due to magnetic fields in the cosmic web and SKA observations
Authors: Akahori Takuya , Ryu Dongsu
Published: March 2015

We estimated that rotation measure (RM) due to the intergalactic magnetic field (IGMF) in the cosmic web is ~ 1–10 rad m−2. The RMs could be tested with the Square Kilometer Array (SKA) and SKA pathfinders.
SpS5 - III. Matter ejection and feedback
Authors: Nazé Yaël , Che Xiao , Cox Nick L. J. , Groh José H. , Guerrero Martin , Kervella Pierre , Lee Chien-De , Matsuura Mikako , Oey M. Sally , Stringfellow Guy S. , Wachter Stephanie
Published: March 2015

The last part of SpS5 dealt with the circumstellar environment. Structures are indeed found around several types of massive stars, such as blue and red supergiants, as well as WRs and LBVs. As shown in the last years, the potential of IR for their study is twofold: first, IR can help discover many previously unknown nebulae, leading to the identification of new massive stars as their progenitors; second, IR can help characterize the nebular features. Current and new IR facilities thus pave the way to a better understanding of the feedback from massive stars.
MarcoPolo-R: Near Earth Asteroid Sample Return Mission candidate as ESA-M3 class mission
Authors: Michel Patrick ,   the MarcoPolo-R Science Study Team
Published: March 2015

MarcoPolo-R is a sample return mission to a primitive Near-Earth Asteroid (NEA) selected in 2011 for the Assessment Study Phase of M3-class missions in the framework of ESAs Cosmic Vision (CV) 2015-2025 programme. The phase A study started at the end of 2012 and will proceed throughout 2013. The final selection by ESA will occur in February 2014. MarcoPolo-R is a European-led mission with a possible contribution from other agencies. MarcoPolo-R will rendez-vous with the primitive NEA 2008 EV5. Before returning a unique sample to Earth, the asteroid will be scientifically characterized at multiple scales. MarcoPolo-R will provide detailed knowledge of the physical and compositional properties of a member of the population of Potentially Hazardous Asteroids (PHA), which is an important contribution to mitigation studies.
Calibration of Star-Formation Rate Measurements Across the Electromagnetic Spectrum
Authors: Buat V. , Braine J. , Dale D. A. , Hornschemeier A. , Lehmer B. , Kroupa P. , Pflamm-Altenburg J. , Popescu C. C. , Wu H. , Zezas A.
Published: March 2015

Star-formation is one of the main processes that shape galaxies, and together with black-hole accretion activity the two agents of energy production in galaxies. It is important on a range of scales from star clusters/OB associations to galaxy-wide and even group/cluster scales. Recently, studies of star-formation in sub-galactic and galaxy-wide scales have met significant advances owing to: (a) developments in the theory of stellar evolution, stellar atmospheres, and radiative transfer in the interstellar medium; (b) the availability of more sensitive and higher resolution data; and (c) observations in previously poorly charted wavebands (e.g. Ultraviolet, Infrared, and X-rays). These data allow us to study more galaxies at ever-increasing distances and nearby galaxies in greater detail, and different modes of star formation activity such as massive star formation and low level continuous star formation in a variety of environments. In this contribution we summarize recent results in the fields of multi-wavelength calibrations of star-formation rate indicators, the Stellar Initial Mass function, and radiative transfer and modeling of the Spectrale Energy Disrtributions of galaxies.
TWINNING between Institutions in developed and less developed countries: an ideal way to set-up an astrophysics program
Authors: Carignan Claude
Published: March 2015

It is very difficult to start from scratch a new Astrophysics program in a country with very little or no researchers in the field. In 2007, we began to set-up an Astrophysics program by TWINNING the Université de Ouagadougou with the Université de Montréal in Canada, the Université de Provence in France and the University of Cape Town in South Africa. Already, courses are given at the undergraduate and Master levels and a teaching Observatory has been built. A 1m research telescope was also moved from the La Silla Observatory in Chile to Burkina Faso and the infrastructure is being built at the moment on mount Djaogari in the north-eastern part of the country. In the meantime, 6 students are doing their PhD in Astrophysics overseas (Canada, France and South Africa) and will become the core of the research group at the Université de Ouagadougou. An engineer is also doing his PhD in Astronomical Instrumentation to help with the maintenance of the equipment on the Research Telescope.
In search of a viable IAU-OAD Regional Node: A case for Africa
Authors: Okere B. I. , Okoh D. C. , Obi I. A. , Okeke P. N. , Opara F. E.
Published: March 2015

The establishment of the IAU Office of Astronomy for Development (OAD) in Cape Town, South Africa, with the aim of using astronomy to stimulate development at all levels including primary, secondary and tertiary education, science research and the public understanding of science is a welcome development to consolidate the gains of IYA2009. To assist the IAU OAD office in achieving its goal of using astronomy as a tool for development, there is need to have OAD regional nodes. In this paper, we present the astronomy activities/programs required of such a Regional Node in Africa and how the Node can play a significant role to realise the vision of Astronomy for a better world!
A statistical view on the galactic cold ISM distribution
Authors: Viktor Tóth L. , Zahorecz Sarolta , Marton Gábor , Verebélyi Erika
Published: March 2015

Inhomogenities were found in the distribution of the cold fraction in the interstellar medium (traced by Planck cold clumps). In large scales there is a significant overdensity on some shells, in small scales there are elongated groups. Critical column density for star formation is N(H2) = 7 × 1021 cm−2.
HII radiative transfer revealed by ionization parameter mapping
Authors: Oey M. S. , Pellegrini E. W. , Winkler P. F. , Points S. D. , Smith R. C. , Jaskot A. E. , Zastrow J.
Published: March 2015

We develop the technique of ionization parameter mapping (IPM) to probe the optical depth of Hii regions, applying our method to the Magellanic Clouds. Our results dramatically clarify the radiative transfer in these galaxies. Based on Sii, Oiii, and Hα imaging from the Magellanic Clouds Emission Line Survey, we find that the frequency of optically thin objects correlates strongly with Hα luminosity and correlates inversely with Hi column density. The aggregate escape fraction for the Lyman continuum is sufficient to ionize the diffuse, warm ionized medium, but the galactic escape fraction is dominated by the few largest Hii regions. The quantitative trends are similar in both the LMC and SMC in spite of their different star formation and Hi properties.
Gas in galactic halos
Authors: Dettmar Ralf-Jürgen
Published: March 2015

The interstellar medium in galactic halos is described as a consequence of feedback mechanisms from processes related to star-formation in the disk. The presence of gas in galactic halos is also expected due to accretion of gas from the circumgalactic environment. The observational evidence for gas in galactic halos - from the hot X-ray emitting coronal phase to cool molecular gas and dust - is reviewed and discussed in the context of current models of the ISM and the “infall vs. outflow“ debate.
HVCs, infall and the Galactic Fountain
Authors: Wakker Bart P.
Published: March 2015

High-velocity clouds (HVCs) consist of gas that does not take part in normal Galactic rotation, having velocities deviating by up to 400 km s−1 from those expected from rotation. Over the past five decades, studies have shown they these clouds trace a number of different processes, including the Galactic Fountain, tidal streams, and infall. Here, I summarize some recent results concerning measurements of cloud metallicities and distances and how these are used to understand individual clouds and derive the conclusion above.
Gas density histograms of galaxies: the observational density probability function of the interstellar gas density
Authors: Toshihiro Handa , Takahiro Yoda , Nario Kuno
Published: March 2015

In the steady state, the probability density function (PDF) of the gaseous interstellar matter (ISM) can be observed as a gas density histogram (GDH) of all cells in the system. We made GDHs of the Milky Way Galaxy (MWG) using Galactic plane surveys in CO lines. We found that the GDH in the MWG is log-normal which suggests that the density structure of the molecular gas is a result of many stochastic processes. Using the Nobeyama CO atlas, we made GDHs of nearby galaxies but in column density. Although some galaxies show log-normal, the others show completely different shapes, suggesting that the density structure of galaxies may be different from galaxy to galaxy.
Very deep spectroscopy of NGC 7009
Authors: Fang Xuan , Liu Xiaowei , Storey Peter J.
Published: March 2015

We report new calculations of the effective recombination coefficients for the nebular N ii and O ii lines and very deep spectroscopy of the bright planetary nebula (PN) NGC 7009.
Modeling deuterium chemistry of interstellar space with large chemical networks
Authors: Albertsson T. , Semenov D. A. , Vasyunin A. I. , Henning Th. , Herbst E.
Published: March 2015

Observations of deuterated species are essential to probing the properties and thermal history of various astrophysical environments, and the ALMA observing facilities will reveal a multitude of new deuterated molecules. To analyze these new vast data we have constructed a new up-to-date network with the largest collection of deuterium chemistry reactions to date. We assess the reliability of the network and probe the role of physical parameters and initial abundances on the chemical evolution of deuterated species. Finally, we perform a sensitivity study to assess the uncertainties in the estimated abundances and D/H ratios.
The IAU Office of Astronomy for Development
Authors: Govender Kevin
Published: March 2015

On 16 April 2011 the IAU's Office of Astronomy for Development (OAD) was launched jointly by the President of the IAU and the South African Minister of Science and Technology, at the South African Astronomical Observatory in Cape Town. This OAD was set up to realise the IAU's strategic plan which aims to use astronomy as a tool for development. Communicating astronomy with the public is one of the OAD's focus areas.
Communicating through Vernacular Media: Scope and Challenges
Authors: Sule A.
Published: March 2015

India is a country with a large number of languages which not only differ in scripts but are essentially part of different language families. “Marathi“ is one such Indian regional language spoken by nearly 70 million people and is the native language of the author. Like all major regional languages, there is a strong and vibrant media in Marathi with 45 odd newspapers and 6 television news channels.
Astronomy Outreach Adventures in Rural Guatemala
Authors: Strubbe L.
Published: March 2015

Astronomy can be an inspirational gateway to learning science and analytical reasoning, and to careers in STEM fields—particularly important in developing countries where educational opportunities can be scarce. Following this idea and my interest in learning about other cultures, I decided to spend 6 weeks in late 2011 (between Ph.D. and postdoc) doing astronomy public outreach in Guatemala. I volunteered through a Spanish language school embedded in a poor rural community (typical earning ~ $3/day), working mostly with children. My teaching goals were primarily attitudinal: to encourage people to observe and ask questions about the world around them, and to show them that phenomena have explanations that we can understand.
More Observations in Schools for Promoting Astronomy and Sky Protection
Authors: Ros Rosa M.
Published: March 2015

In astronomy it is important to promote observation and the quality of the sky is essential for a good observation impact. It is important that children have a nice memory of their observations in a non-polluted sky. Using students as agents of change it is possible to promote good practice for sky protection in society.
A new Starlight Reserve for the central South Island of New Zealand
Authors: Hearnshaw John
Published: March 2015

The Aoraki Mackenzie International Dark Sky Reserve is a new reserve created in 2012 by the International Dark-Sky Association in the central South Island of New Zealand, and covers over 4300 square kilometres around Mt John University Observatory. It is the first such reserve to be recognized at gold tier level and is the largest dark sky reserve in the world. Astro-tourism in the new reserve will be a prominent activity in the coming years.
Assessing the contribution from different parts of Canary islands to the hemispheric spectral sky radiance levels over European Northern Observatories
Authors: Aubé Martin
Published: March 2015

In this paper, we suggest to use a sky radiance model which accounts for heterogeneous distribution of light fixtures, their photometry, the ground reflectance and topography, to infer the point to point contribution of Canary Islands to the artificial sky radiance at Observatorio del Teide (Tenerife) and Observatorio Roque de los Muchachos (La Palma). In-situ hyperspectral sky radiance measurements, acquired on site in 2010, have been used to calibrate the model and to evaluate its inherent error. We aim to identify and characterize zones at which any lighting level increase or decrease may have a larger impact on light pollution at both European Northern Observatory sites, and then help to control and/or reduce their light pollution levels. This innovative methodology, can then be seen as a high level decision tool to help local authorities to restrict or reduce light pollution with the objective of protecting research class astronomical sites.
An Introduction to IAU 2009 Resolution B5
Authors: Smith Malcolm G.
Published: March 2015

For the purposes of the discussion of IAU follow up on Resolution B5, adopted at the GA in Rio de Janiero in 2009, reference is made here to the resolution itself and the background which led to its proposal and adoption by the IAU.
Light Pollution and Protecting Astronomical Sites in China
Authors: Green Richard F.
Published: March 2015

Prof. Baozhou Zhang hosted a meeting of IAU Commission 50 members with Chinese academics and lighting professionals at Beijing Normal University.
Design of angular and polarization stable modified circular ring frequency selective surface for satellite communication system
Authors: Bharti Garima , Jha Kumud Ranjan , Singh Ghanshyam , Jyoti Rajeev
Published: March 2015

In this paper, a simple synthesis technique to obtain the geometrical parameters of the modified circular ring for angular and polarizations (perpendicular and parallel) stable frequency selective surface (FSS) has been discussed. The geometrical parameters of the modified circular ring FSS structure have been achieved using the proposed synthesis technique, which is based on the equivalent circuit (EC) approach. In addition to this, the numerical analysis is also discussed to determine the values of EC parameters, which depends on the basic system level characteristics such as frequency of operation and reflection/transmission coefficients. The analytical results are supported using the full-wave three-dimensional electromagnetic (EM) simulators such as CST Microwave Studio and Ansoft HFSS. The sensitivity of the structure to the perpendicular and parallel polarized EM wave up to 50° angle-of-incidences (AOIs) has been discussed. The stability over different AOI is attributed to the appropriate thickness of the structure with its small unit-cell dimensions. We have also fabricated and experimentally tested the proposed FSS structure.
Decoding the ‘embryonic’ nature of embryonal rhabdomyosarcoma
Authors: Lav R. , Heera R. , Cherian L. M.
Published: March 2015

Embryonal rhabdomyosarcoma is one of the major defined histologic variants of rhabdomyosarcoma that is mainly reported in children. The histologic appearance of this neoplastic entity recapitulates normal myogenesis. The tumor cells variably exhibit the different cellular phases of myogenesis ranging from undifferentiated mesenchymal cells to elongated myoblasts, multinucleated myotubes and differentiated muscle fibers. The carefully orchestrated embryonic signaling pathways that are involved in myogenesis, conceivably also result in the genesis of rhabdomyosarcoma; albeit as a corollary to an imbalance. We have attempted to review the pathogenesis of embryonal rhabdomyosarcoma in an endeavor to understand better, how closely it is linked to normal myogenesis in terms of its molecular dynamics and histologic presentation.