bluuebunny/crossref_metadata_2025 huggingface dataset:
Revealing galactic scale bars with the help of Galaxy Zoo
Authors: Masters Karen L. ,   the Galaxy Zoo Team
Published: March 2015

We use visual classifications of the brightest 250,000 galaxies in the Sloan Digital Sky Survey Main Galaxy Sample provided by citizen scientists via the Galaxy Zoo project (www.galaxyzoo.org, Lintott et al. 2008) to identify a sample of local disc galaxies with reliable bar identifications.

These data, combined with information on the atomic gas content from the ALFALFA survey (Haynes et al. 2011) show that disc galaxies with higher gas content have lower bar fractions.

We use a gas deficiency parameter to show that disc galaxies with more/less gas than expected for their stellar mass are less/more likely to host bars. Furthermore, we see that at a fixed gas content there is no residual correlation between bar fraction and stellar mass. We argue that this suggests previously observed correlations between galaxy colour/stellar mass and (strong) bar fraction (e.g. from the sample in Masters et al. 2011, and also see Nair & Abraham 2010) could be driven by the interaction between bars and the gas content of the disc, since more massive, optically redder disc galaxies are observed to have lower gas contents.

Furthermore we see evidence that at a fixed gas content the global colours of barred galaxies are redder than those of unbarred galaxies. We suggest that this could be due to the exchange of angular momentum beyond co-rotation which might stop a replenishment of gas from external sources, and act as a source of feedback to temporarily halt or reduce the star formation in the outer parts of barred discs.

These results (published as Masters et al. 2012) combined with those of Skibba et al. (2012), who use the same sample to show a clear (but subtle and complicated) environmental dependence of the bar fraction in disc galaxies, suggest that bars are intimately linked to the evolution of disc galaxies.
Kinematical evidence for secular evolution in Spitzer Survey of Stellar Structure in Galaxies (S4G) spirals
Authors: Erroz-Ferrer Santiago , Knapen Johan H. , Font Joan , Beckman John E. ,   the S4G team
Published: March 2015

We present a study of the kinematics of a sample of isolated spiral galaxies in the Spitzer Survey of Stellar Structure in Galaxies (S4G). We use Hα Fabry-Perot data from the GHαFaS instrument at the William Herschel Telescope (WHT) in La Palma, complemented with images at 3.6 microns, in the R band and in the Hα filter. The resulting data cubes and velocity field maps allow a complete study of the kinematics of a galaxy, including in-depth investigations of the rotation curve, velocity moment maps, velocity residual maps, gradient maps and position-velocity (PV) diagrams. We find clear evidence of the secular evolution processes going on in these galaxies, such as asymmetries in the velocity field in the bar zone, and non-circular motions, probably in response to the potential of the structural components of the galaxies, or to past or present interactions.
Characterization of peculiar early-type galaxies in the local universe
Authors: Ramos Beatriz H. F. , Menéndez-Delmestre Karín , Kim Taehyun , Sheth Kartik ,   S4G team
Published: March 2015

Early-type galaxies (ETGs) have been characterized as objects dominated by old stellar populations, containing little or no cold gas and dust, and thus, non-existent star formation. However, there are indications in the literature that some ETGs deviate from this: some have significant amounts of gas and dust, are forming stars, and/or display stellar substructures (tidal features, disks or shells, e.g., Kormendy et al. 1997, Rix, Carollo & Freeman 1999). A better understanding of the evolution of ETGs and the details of their “peculiarities” is critical to properly constrain models of galaxy formation. We present preliminary results on a photometric analysis of substructures in local ETGs, based on 3.6μm IRAC images from the Spitzer Survey of Stellar Structure in Galaxies (S4G; Sheth et al. 2010), which comprises one of the largest mid-IR photometric surveys of the local Universe. Relatively unhindered by extinction and dominated by the low-mass stellar populations that dominate a galaxy's stellar mass budget, the IR is the ideal waveband to trace the details of stellar structures in galaxies. Based on 2D GALFIT (Peng et al. 2002) decomposition, we find tidal features in 17% of 146 ETGs from S4G. For both the GALFIT model and the galaxy residual images, we calculate the total counts inside an annular region centered on the galaxy, where the inner radius is the effective radius of the galaxy. Assuming that a tidal feature and its host galaxy have the same mass-to-luminosity ratio (M/L), the ratio of the residual counts over model counts translates into the ratio of their stellar masses. We find that the tidal features in the majority of peculiar ETGs in our sample account for no more than 11% of the galaxy's total stellar mass. Considering that simulations (Canalizo et al. 2007) suggest an upper limit in relative stellar mass of 25% for shells resulting from a past major merger, the values we find support a merger origin. We are in the process of applying the decomposition method to GALEX UV images and optical SDSS images of these peculiar ETGs in order to characterize the underlying substructure and provide constraints on astrophysical properties such as star formation rates and stellar masses associated to these tidal features, based on broad-band SED template fitting techniques.
The origin of thick discs
Authors: Comerón Sébastien
Published: March 2015

Thick discs are defined to be disc-like components with a scale height larger than that of the classical discs. They are ubiquitous (Yoachim & Dalcanton 2006; Comerón et al. 2011a), they are made of mostly old and metal-poor stars and are most easily detected in close to edge-on galaxies. Their origin has been considered mysterious and several formation theories have been proposed:

• The thick disc being formed secularly by thin disc stars heated by disc overdensities such as giant molecular clouds or spiral arms (Villumsen 1985, ApJ, 290, 75) and by stars moved outwards from their original orbits by radial migration mechanisms (Schönrich & Binney 2009).

• The thick disc being formed by the heating of the thin disc by satellites (Quinn et al. 1993) and the tidal stripping of them (Abadi et al. 2003).

• The thick disc being formed fast and already thick at high redshift in an highly unstable disc. Inside that thick disc, a thin disc would form afterwards as suggested by Elemgreen & Elmegreen (2006).

• The thick disc being formed originally thick at high redshift by the merger of gas-rich protogalactic fragments and a thin disc forming afterwards within it (Brook et al. 2007).

The first mechanism is a secular evolution mechanism. The time-scale of the second one is dependent on the merger history of the main galaxy. In the two last mechanisms, the thick disc forms already thick in a short time-scale at high redshift.

Recent Milky Way studies, (see, e.g., Bovy et al. 2012), have shown indications that there is no discontinuity between the thin and the thick disc chemical and kinematic properties. Instead, those studies indicate the presence of a monotonic distribution of disc thicknesses. This would suggest a secular origin for the Milky Way thick disc.

Studies in external galaxies (Yoachim & Dalcanton 2006; Comerón et al. 2011b), have shown that low-mass disc galaxies have thick disc relative masses much larger than those found in large-mass galaxies. Because low-mass galaxies are dynamically younger than their larger counterparts, it seems difficult for their thick discs to have a secular evolution origin, but simulations show that their thick disc masses are compatible with those of a thick disc formed at high redshift.

Thus, recent studies seem to indicate that large-mass galaxies have their thick discs formed mainly due to secular evolution and that low-mass galaxies have them formed at high redshift.
Secular Evolution in the Milky Way
Authors: Debattista Victor
Published: March 2015

I will review the secular evolution of the Milky Way disk and bulge with particular attention to the bulge and disk. Evidence for the importance of stellar migration in the Solar neighbourhood will be presented. The upcoming Gaia satellite will lead to a wealth of new data with which to explore these effects.
Radial migration in barred galaxies
Authors: Di Matteo P. , Haywood M. , Combes F. , Semelin B. , Babusiaux C. , Gomez A.
Published: March 2015

In this talk, I will present the result of high resolution numerical simulations of disk galaxies with various bulge/disk ratios evolving isolated, showing that:

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Most of migration takes place when the bar strength is high and decreases in the phases of low activity (in agreement with the results by Brunetti et el. 2011, Minchev et al. 2011).

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Most of the stars inside the corotation radius (CR) do not migrate in the outer regions, but stay confined in the inner disk, while stars outside CR can migrate either inwards or outwards, diffusing over the whole disk.

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Migration is accompanied by significative azimuthal variations in the metallicity distribution, of the order of 0.1 dex for an initial gradient of ~-0.07 dex/kpc.

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Boxy bulges are an example of stellar structures whose properties (stellar content, vertical metallicity, [α/Fe] and age gradients, ..) are affected by radial migration (see also Fig. 1).
Disk structures in the CGS Survey
Authors: Li Zhao-Yu , Ho Luis , Barth Aaron , Peng Chien
Published: March 2015

The Carnegie-Irvine Galaxy Survey (CGS) is a long term program to investigate the photometric and spectroscopic properties of a statistically complete sample of 605 bright (BT < 12.9 mag), southern (delta < 0 deg) galaxies using the facilities at Las Campanas Observatory. For each galaxy, we have broadband images (BVRI) with good seeing (≈1″) and deep surface brightness (≈27.5 B-band). Using the IRAF task ELLIPSE and the fourier decomposition method, we measured the bar and the lopsidedness properties of disk galaxies in the CGS sample. Our results show that the bar fraction is lower in the early-type galaxies than that in the late-type ones. The (relative) bar length is longer in early-type ones, and strong bars are rare (the one with large ellipticity). We find that the lopsidedness is independent on the galaxy environment, and correlation studies suggest that the lopsided disk may have helped drive gas inward to form stars.
Dynamical evolution of star clusters in transient spiral arms
Authors: Fujii Michiko , Baba Junichi
Published: March 2015

Star clusters are one of fundamental building blocks of galactic disks. They form in a potential well of spiral arms and travel in the disk. We performed N-body simulation of star clusters in stellar disk with “live” spiral arms. In this simulation, both star clusters and stellar disks are modeled as N-body systems. We found that star clusters migrated in the galactic disk in a timescale of their galactic rotation. The tidal tails spread over a few kpc, but they might be detectable if we are able to measure their velocity.
The influence of halo evolution on galaxy structure
Authors: White Simon
Published: March 2015

If Einstein-Newton gravity holds on galactic and larger scales, then current observations demonstrate that the stars and interstellar gas of a typical bright galaxy account for only a few percent of its total nonlinear mass. Dark matter makes up the rest and cannot be faint stars or any other baryonic form because it was already present and decoupled from the radiation plasma at z = 1000, long before any nonlinear object formed. The weak gravito-sonic waves so precisely measured by CMB observations are detected again at z = 4 as order unity fluctuations in intergalactic matter. These subsequently collapse to form today's galaxy/halo systems, whose mean mass profiles can be accurately determined through gravitational lensing. High-resolution simulations link the observed dark matter structures seen at all these epochs, demonstrating that they are consistent and providing detailed predictions for all aspects of halo structure and growth. Requiring consistency with the abundance and clustering of real galaxies strongly constrains the galaxy-halo relation, both today and at high redshift. This results in detailed predictions for galaxy assembly histories and for the gravitational arena in which galaxies live. Dark halos are not expected to be passive or symmetric but to have a rich and continually evolving structure which will drive evolution in the central galaxy over its full life, exciting warps, spiral patterns and tidal arms, thickening disks, producing rings, bars and bulges. Their growth is closely related to the provision of new gas for galaxy building.
Galaxies in most dense environments at z ~ 1.4
Authors: Strazzullo V.
Published: March 2015

The X-ray luminous system XMMU J2235-2557 at z~1.4 is among the most massive of the very distant galaxy clusters, and remains a unique laboratory to observe environment-biased galaxy evolution already 9 Gyr ago (Lidman et al.2008, Rosati et al.2009, Strazzullo et al.2010). At a cosmic time when cluster cores start showing evidence of a still active galaxy population, star-forming (M>1010M⊙) galaxies in XMMU J2235-2557 are typically located beyond ~250kpc from the cluster center, with the cluster core already effectively quenched and dominated by massive galaxies on a tight red sequence, showing early-type spectral features and bulge-dominated morphologies. While masses and stellar populations of these red-sequence galaxies suggest that they have largely completed their formation, their size is found to be typically smaller that similarly massive early-type galaxies in the local Universe, in agreement with many high-redshift studies. This would leave room for later evolution, likely through non-secular processes, changing their structure to match their local counterparts. On the other hand, uncertainties and biases in the determination of masses and sizes, as well as in the local mass-size relation, and the possible effect of progenitor bias, still hamper a final conclusion on the actual relevance of size evolution for early-type galaxies in this dense high-redshift environment.
Testing galaxy formation models with the GHOSTS survey: The stellar halo of M81
Authors: Monachesi A. , Bell E. , Radburn-Smith D. , Vlajić M. , de Jong R. , Bailin J. , Dalcanton J. , Holwerda B. , Streich D.
Published: March 2015

The GHOSTS survey is the largest study to date of the resolved stellar populations in the outskirts of disk galaxies (Radburn-Smith et al.2011). The sample currently consists of 16 nearby disk galaxies, whose outer disks and halos are imaged with the Hubble Space Telescope (HST). I will present new results obtained from the study of 19 GHOSTS fields in M81's outermost part. The observed fields probe the stellar halo of M81 out to projected distances of ~50 kpc, an unprecedented distance for halo studies outside the Local Group. The 50% completeness levels of the color magnitude diagrams are typically at 2.5 mag below the tip of the red giant branch. When considering only fields located at galactocentric radius R > 15 kpc, we detect no color gradient in the stellar halo of M81. We compare these results with model predictions for the colors of stellar halos formed purely via accretion of satellite galaxies (Bullock & Johnston 2005). When we analyze the cosmologically motivated models in the same way as the HST data, we find that they predict no color gradient for the stellar halos, in good agreement with the observations (see Fig. 1).
The history of polarisation measurements: their role in studies of magnetic fields
Authors: Wielebinski R.
Published: March 2015

Radio astronomy gave us new methods to study magnetic fields. Synchrotron radiation, the main cause of comic radio waves, is highly linearly polarised with the ‘E’ vector normal to the magnetic field. The Faraday Effect rotates the ‘E’ vector in thermal regions by the magnetic field in the line of sight. Also the radio Zeeman Effect has been observed.
Near-infrared Polarimetry and Interstellar Magnetic Fields in the Galactic Center
Authors: Nishiyama S. , Hatano H. , Nagata T. , Tamura M.
Published: March 2015

We present a large-scale view of the magnetic field (MF) in the central 3° × 2° region of our Galaxy. There is a smooth transition of the large-scale MF configuration in this region.
MAGMO: Mapping the Galactic Magnetic field through OH masers
Authors: Green James A. , McClure-Griffiths Naomi M. , Caswell James L. , Robishaw Tim , Harvey-Smith Lisa , Mao Sui Ann
Published: March 2015

We are undertaking a project (MAGMO) to examine large-scale magnetic fields pervading regions of high-mass star formation. The project will test if the orientations of weak large-scale magnetic fields can be maintained in the contraction (and field amplification) to the high densities encountered in high-mass star forming regions. This will be achieved through correlating targeted observations of ground-state hydroxyl (OH) maser emission towards hundreds of sites of high-mass star formation spread throughout the spiral arms of the Milky Way. Through the Zeeman splitting of the OH maser emission these observations will determine the strength and orientation of the in-situ magnetic field. The completion of the southern hemisphere Methanol Multibeam survey has provided an abundance of targets for ground-state OH maser observations, approximately 1000 sites of high-mass star formation. With this sample, much larger and more homogeneous than previously available, we will have the statistics necessary to outweigh random fluctuations and observe an underlying Galactic magnetic field if it exists. We presented details of the overall progress of the project illustrated by the results of a pilot sample of sources towards the Carina-Sagittarius spiral arm tangent, where a coherent field is implied.
MHD turbulence in the intracluster medium
Authors: Falceta-Gonçalves Diego , Kowal G. , de Gouveia Dal Pino E. , Santos-Lima R. , Nakwacki S. , Lazarian A.
Published: March 2015

In this work we discuss the turbulent evolution of structures in the intracluster medium based on the two fluid approximations: MHD and collisionless plasma under Chew Goldberger Low (CGL) closure. Turbulence excited by galactic motions and gas inflow in intracluster medium will develop in very different ways considering the two fluid approaches. Statistics of density distributions, and velocity and magnetic fields are provided. Compared to the standard MHD case, the instabilities that arise from CGL-MHD models strongly modify the probability distribution functions of the plasma velocity and density, basically increasing their dispersion. Moreover, the spectra of both density and velocity show increased power at small scales, due to the instabilities growth rate that are larger as smaller scales. Finally, in high beta plasmas, i.e. B2 << P, a fast increase of the magnetic energy density is observed in the CGL-MHD models, faster than the standard MHD turbulent dynamo that operates at timescales τ ~ L/vL. The signatures of the increased power at small scales and the increase of magnetic field intensity from CGL-MHD models could be observed at radio wavelengths. A comparison of the structure function of the synchrotron emission, as well as the statistics of Faraday rotation effects on the synchrotron polarization, for both the MHD and CGL-MHD models is provided.
SpS5 - I. Obscured and distant clusters
Authors: Hanson M. M. , Froebrich D. , Martins F. , Chené A.-N. , Rosslowe C. , Herrero A. , Kim H.-J.
Published: March 2015

This first part of Special Session 5 explored the current status of infrared-based observations of obscured and distant stellar clusters in the Milky Way galaxy. Recent infrared surveys, either serendipitously or using targeted searches, have uncovered a rich population of young and massive clusters. However, cluster characterization is more challenging as it must be obtained often entirely in the infrared due to high line-of-sight extinction. Despite this, much is to be gained through the identification and careful analysis of these clusters, as they allow for the early evolution of massive stars to be better constrained. Further, they act as beacons delineating the Milky Way's structure and as nearby, resolved analogues to the distant unresolved massive clusters studied in distant galaxies.
Astronomy for a Better World: IAU OAD Task Force-1 Programs for Advancing Astronomy Education and Research in Universities in Developing Countries
Authors: Guinan Edward , Kolenberg Katrien
Published: March 2015

We discuss the IAU Commission 46 and Office for Astronomy Development (OAD) programs that support advancing Astronomy education and research primarily in universities in developing countries. The bulk of these operational activities will be coordinated through the OAD's newly installed Task Force 1. We outline current (and future) IAU/OAD Task Force-1 programs that promote the development of University-level Astronomy at both undergraduate and graduate levels. Among current programs discussed are the past and future expanded activities of the International School for Young Astronomers (ISYA) and the Teaching Astronomy for Development (TAD) programs. The primary role of the ISYA program is the organization of a three week School for students for typically M.Sc. and Ph.D students. The ISYA is a very successful program that will now be offered more frequently through the generous support of the Kavli Foundation. The IAU/TAD program provides aid and resources for the development of teaching, education and research in Astronomy. The TAD program is dedicated to assist countries that have little or no astronomical activity, but that wish to develop or enhance Astronomy education. Over the last ten years, the ISYA and TAD programs have supported programs in Africa, Asia, Central America and the Caribbean, the Middle East, South East and West Asia, and South America. Several examples are given.

Several new programs being considered by OAD Task Force-1 are also discussed. Other possible programs being considered are the introduction of modular Astronomy courses into the university curricula (or improve present courses) as well as providing access to “remote learning“ courses and Virtual Astronomy labs in developing countries. Another possible new program would support visits of astronomers from technically advanced countries to spend their sabbatical leaves teaching and advising University Astronomy programs in developing countries. Suggestions for new Task Force -1 programs are also welcomed. Useful information about the participation of IAU members and volunteers in these programs will be discussed and practical information will be provided.
NAOJ's activities on Astronomy for Development: Aiding Astronomy Education in Developing Nations
Authors: Sekiguchi K. , Yoshida F.
Published: March 2015

We summarize NAOJ's efforts to promote astronomy in developing nations. The Office of International Relations, collaborations with the Office of Public Outreach at NAOJ and with the East Asia Core Observatories Association (EACOA), has engaged children, students and educators about astronomy development in the Asia-Pacific region. In particular, we introduce “You are Galileo!“ project, which is a very well received astronomy education program for children. We also report on a continuing effort by the Japanese Government in support of astronomy programs in the developing nations.
Modern view of the warm ionized medium
Authors: Hill A. , Reynolds R. , Haffner L. , Wood K. , Madsen G.
Published: March 2015

We review the observational evidence that the warm ionized medium (WIM) is a major and physically distinct component of the Galactic interstellar medium. Although up to ~ 20% of the faint, high-latitude Hα emission in the Milky Way may be scattered light emitted in midplane Hii regions, recent scattered light models do not effectively challenge the well-established properties of the WIM.
Formation of structures around HII regions: ionization feedback from massive stars
Authors: Tremblin P. , Audit E. , Minier V. , Schmidt W. , Schneider N.
Published: March 2015

We present a new model for the formation of dense clumps and pillars around HII regions based on shocks curvature at the interface between a HII region and a molecular cloud. UV radiation leads to the formation of an ionization front and of a shock ahead. The gas is compressed between them forming a dense shell at the interface. This shell may be curved due to initial interface or density modulation caused by the turbulence of the molecular cloud. Low curvature leads to instabilities in the shell that form dense clumps while sufficiently curved shells collapse on itself to form pillars. When turbulence is high compared to the ionized-gas pressure, bubbles of cold gas have sufficient kinetic energy to penetrate into the HII region and detach themselves from the parent cloud, forming cometary globules.

Using computational simulations, we show that these new models are extremely efficient to form dense clumps and stable and growing elongated structures, pillars, in which star formation might occur (see Tremblin et al.2012a). The inclusion of turbulence in the model shows its importance in the formation of cometary globules (see Tremblin et al.2012b). Globally, the density enhancement in the simulations is of one or two orders of magnitude higher than the density enhancement of the classical “collect and collapse“ scenario. The code used for the simulation is the HERACLES code, that comprises hydrodynamics with various equation of state, radiative transfer, gravity, cooling and heating.

Our recent observations with Herschel (see Schneider et al.2012a) and SOFIA (see Schneider et al.2012b) and additional Spitzer data archives revealed many more of these structures in regions where OB stars have already formed such as the Rosette Nebula, Cygnus X, M16 and Vela, suggesting that the UV radiation from massive stars plays an important role in their formation. We present a first comparison between the simulations described above and recent observations of these regions.
ISM simulations: an overview of models
Authors: de Avillez M. A. , Breitschwerdt D. , Asgekar A. , Spitoni E.
Published: March 2015

Until recently the dynamical evolution of the interstellar medium (ISM) was simulated using collisional ionization equilibrium (CIE) conditions. However, the ISM is a dynamical system, in which the plasma is naturally driven out of equilibrium due to atomic and dynamic processes operating on different timescales. A step forward in the field comprises a multi-fluid approach taking into account the joint thermal and dynamical evolutions of the ISM gas.
Numerical modeling of multiphase, turbulent galactic disks with star formation feedback
Authors: Kim Chang-Goo , Ostriker Eve C. , Kim Woong-Tae
Published: March 2015

Star formation is self-regulated by its feedback that drives turbulence and heats the gas. In equilibrium, the star formation rate (SFR) should be directly related to the total (thermal plus turbulent) midplane pressure and hence the total weight of the diffuse gas if energy balance and vertical dynamical equilibrium hold simultaneously. To investigate this quantitatively, we utilize numerical hydrodynamic simulations focused on outer-disk regions where diffuse atomic gas dominates. By analyzing gas properties at saturation, we obtain relationships between the turbulence driving and dissipation rates, heating and cooling rates, the total midplane pressure and the total weight of gas, and the SFR and the total midplane pressure. We find a nearly linear relationship between the SFR and the midplane pressure consistent with the theoretical prediction.
Planck's view of the intestellar medium
Authors: Tauber J. A.
Published: March 2015

Planck is a cosmology experiment, but significant interstellar dust and gas emission exists in the band where the CMB peaks. Therefore, Planck's all-sky surveys provide new views of the ISM and magnetic fields in the Galaxy, as well as the dust and gas in galaxies.
The resolved magnetic fields of the quiescent cloud GRSMC 45.60+0.30
Authors: Pavel Michael D. , Marchwinski Robert C. , Clemens Dan P.
Published: March 2015

Marchwinski et al. (2012) mapped the magnetic field strength across the quiescent cloud GRSMC 45.60+0.30 (shown in Figure 1 subtending 40x10 pc at a distance of 1.88 kpc) with the Chandrasekhar-Fermi method CF; Chandrasekhar & Fermi 1953) using near-infrared starlight polarimetry from the Galactic Plane Infrared Polarization Survey (Clemens et al.2012a, b) and gas properties from the Galactic Ring Survey (Jackson et al.2006). The large-scale magnetic field is oriented parallel to the gas-traced ‘spine’ of the cloud. Seven ‘magnetic cores’ with high magnetic field strength were identified and are coincident with peaks in the gas column density. Calculation of the mass-to-flux ratio (Crutcher 1999) shows that these cores are exclusively magnetically subcritical and that magnetostatic pressure can support them against gravitational collapse.
Size distribution of SNRs and the ISM
Authors: Asvarov Abdul I.
Published: March 2015

Based on the very general assumptions on evolution, we have modeled the statistics of SNRs evolving at various initial and environmental conditions. The method is applied to M33, for which the value of the filling factor of the hot phase of the ISM is estimated to be ~ 10%.
The Inflativerse – The University of Nottingham's inflatable planetarium
Authors: Ownsworth J. R. , Haeussler B. , Johnston E. , Hatch N.
Published: March 2015

The Inflativerse is a mobile planetarium run by volunteers lead by the Physics and Astronomy departments at the University of Nottingham. This is a new project set up in 2011 to offer free of charge planetarium shows and activities for schools and public events.
Communicating astronomy with the public for scientists
Authors: Girola R.
Published: March 2015

This article intends to convey the improvement regarding the knowledge exchange in the astronomical field through an improvement in the quality of professional communication between researchers, teachers and the like whose job is to broadcast astronomical concepts. It has been a couple of years since the difficulty of communicating astronomical concepts decreased due to institutional projects, schools and education systems. Inside the education system, the need to include astronomy as an innovative element in curricula has become obvious. Outside, an informal public interested in astronomy became greater in number and began to be fostered by different organizations which spread their astronomical knowledge via workshops and demonstrations.
The challengers of an astronomer being a journalist
Authors: Podorvanyuk N.
Published: March 2015

As the weakness of russian astronomers in observational astronomy became chronic Russia should enter European Southern Observatory. But the Russian government is still not providing any financing of the entrance of Russia to ESO. The author states this situation as an example of his experience of work as an astronomer and as a journalist at the same time.
Australian sites of astronomical heritage
Authors: Stevenson T. , Lomb N.
Published: March 2015

The heritage of astronomy in Australia has proven an effective communication medium. By interpreting science as a social and cultural phenomenon new light is thrown on challenges, such as the dispersal of instruments and problems identifying contemporary astronomy heritage. Astronomers are asked to take note and to consider the communication of astronomy now and in the future through a tangible heritage legacy.
Optical Surveys of Galaxies: Past, Present, and Future
Authors: Okamura Sadanori
Published: March 2015

A brief history is given of wide area optical surveys of galaxies and resulting catalogs, starting from the Shapley-Ames Catalog through POSS and CfA surveys to modern surveys. Scientific impacts of large surveys are described in terms of the complete sample, large homogeneous samples, and new discoveries. Upcoming and future ambitious surveys are also mentioned. A recent review of surveys in various wavelength regions is given by Djorgovski et al. (2012).
LSST Data Management: Entering the Era of Petascale Optical Astronomy
Authors: Juric Mario , Tyson Tony
Published: March 2015

The Large Synoptic Survey Telescope (LSST; Ivezic et al.2008, http://lsst.org) is a planned, large-aperture, wide-field, ground-based telescope that will survey half the sky every few nights in six optical bands from 320 to 1050 nm. It will explore a wide range of astrophysical questions, ranging from discovering killer asteroids, to examining the nature of dark energy. LSST will produce on average 15 terabytes of data per night, yielding an (uncompressed) data set of 200 petabytes at the end of its 10-year mission. Dedicated HPC facilities (with a total of 320 TFLOPS at start, scaling up to 1.7 PFLOPS by the end) will process the image data in near real time, with full-dataset reprocessing on annual scale. The nature, quality, and volume of LSST data will be unprecedented, so the data system design requires petascale storage, terascale computing, and gigascale communications.
Kernel PCA for Supernovae Photometric Classification
Authors: Ishida Emille E. O.
Published: March 2015

In this work, we propose the use of Kernel Principal Component Analysis (KPCA) combined with k = 1 nearest neighbor algorithm (1NN) as a framework for supernovae (SNe) photometric classification. It is specially recommended for analysis where the user is interested in high purity in the final SNe Ia sample. Our method provide good purity results in all data sample analyzed, when SNR⩾5. As a consequence, we can state that if a sample as the Supernova Photometric Classification Challenge were available today, we would be able to classify ≈ 15% of the initial data set with purity higher than 90%. This makes our algorithm ideal for a first approach to an unlabeled data set or to be used as a complement in increasing the training sample for other algorithms. Results are sensitive to the information contained in each light curve, as a consequence, higher quality data (low noise) leads to higher successful classification rates.
Unidentified Infrared Emission Features
Authors: Joblin Christine
Published: March 2015

When referring to unidentified infrared emission features, one has in mind the series of aromatic IR bands (AIBs) between 3.3 and 15 μm that are observed in emission in many environments where UV photons irradiate interstellar matter. These bands are now used by astronomers to classify objects and characterize local physical conditions. However, a deep analysis cannot proceed without understanding the properties of the band carriers. Large polycyclic aromatic hydrocarbon molecules are attractive candidates but interstellar species are still poorly characterized. Various studies emphasize the need for tackling the link between molecular aromatic species, aliphatic material and very small carbonaceous grains. Other unidentified emission features such as the 6.9, 21 and 30 μm bands could be involved in the evolutionary scenario.
Prebiotic Matter in Space
Authors: Ehrenfreund Pascale , Elsaesser Andreas , Groen J.
Published: March 2015

A significant number of molecules that are used in contemporary biochemistry on Earth are found in interstellar and circumstellar regions as well as solar system environments. In particular small solar system bodies hold clues to processes that formed our solar system. Comets, asteroids, and meteorite delivered extraterrestrial material during the heavy bombardment phase ~3.9 billion years ago to the young planets, a process that made carbonaceous material available to the early Earth. In-depth understanding of the organic reservoir in different space environments as well as data on the stability of organic and prebiotic material in solar system environments are vital to assess and quantify the extraterrestrial contribution of prebiotic sources available to the young Earth.
Laboratory Simulations of Physico-chemical Processes under Interstellar Conditions
Authors: Caro Guillermo M. Muñoz
Published: March 2015

The accretion and desorption of gas molecules on cold dust grains play an important role in the evolution of dense clouds and circumstellar regions around YSOs. Some of the gas molecules detected in interstellar clouds were likely synthesized in icy dust grains and ejected to the gas. But in dark cloud interiors, with temperatures as low as 10–20 K, thermal desorption is negligible and a non-thermal mechanism like ice photodesorption is required. Reactions in the ice matrix are driven by energetic processing such as photon and ion irradiation. In circumstellar regions the photon flux (UV and X-rays) is expected to be significantly higher than in dense cloud interiors, icy grain mantles present in the outer parts will experience significant irradiation. The produced radicals lead to the formation of new species in the ice, some of them of prebiotic interest. Laboratory simulations of these processes are required for their understanding. The new ultra-high vacuum set-ups introduce some important improvements.
Laboratory Analogues of the Carbonaceous Dust: Synthesis of Soot-like Materials and their Properties
Authors: Pino T. , Carpentier Y. , Féraud G. , Bréchignac Ph. , Brunetto R. , d'Hendecourt L. , Dartois E. , Rouzaud J.-N.
Published: March 2015

Carbonaceous cosmic dust is observed through infrared spectroscopy either in absorption or in emission and the details of the spectral features are believed to shed some light on its structure and finally enable the study of its life cycle. Other spectral domains also contain some information, as does the UV bump at 217 nm. In order to progress on the understanding of these spectral features, many laboratory works are devoted to the production and characterization of laboratory analogues. Generally several analytical tools are used in combination to better analyse the intimate structure of the analogues and the influence of the nanostructuration on the spectral properties. In this proceeding We will focus on the elaboration of new spectral parameters that enables the nanostructuration of the carriers of the AIBs to be traced.
CTA site characterization: a contribution on Sky Background Brightness
Authors: de la Vega Gonzalo , García Beatriz , Maya Javier , Mancilla Alexis , Rosemblat Ezequiel
Published: March 2015

The Cherenkov Telescope Array (CTA) is an international project for which more than 1000 scientists from 27 countries work together to install two observatories, one in the southern hemisphere and the other in the north, to study gamma-ray radiation. Argentina is a candidate site for one of the observatories, and to characterize proposed sites, one must study the sky background brightness. This critical point must be studied with care. Nearest cities can be a decisive factor in determining where to locate an observatory in our times.
IAU Resolution 2009 B5 - Commission 50 Draft Action Plan - Presentation and Discussion
Authors: Green R. F.
Published: March 2015

IAU Resolution 2009 B5 calls on IAU members to protect the public's right to an unpolluted night sky as well as the astronomical quality of the sky around major research observatories. The multi-pronged approach of Commission 50 includes working with the lighting industry for appropriate products from the solid state revolution, arming astronomers with training and materials for presentation, selective endorsement of key protection issues, cooperation with several other IAU commissions for education and outreach, and provision of clear quantitative priorities for outdoor lighting standards.
Exome Sequencing to Detect Rare Variants Associated With General Cognitive Ability: A Pilot Study
Authors: Luciano Michelle , Svinti Victoria , Campbell Archie , Marioni Riccardo E. , Hayward Caroline , Wright Alan F. , Taylor Martin S. , Porteous David J. , Thomson Pippa , Prendergast James G.D. , Hastie Nicholas D. , Farrington Susan M. , Scotland Generation , Dunlop Malcolm G. , Deary Ian J.
Published: March 2015

Variation in human cognitive ability is of consequence to a large number of health and social outcomes and is substantially heritable. Genetic linkage, genome-wide association, and copy number variant studies have investigated the contribution of genetic variation to individual differences in normal cognitive ability, but little research has considered the role of rare genetic variants. Exome sequencing studies have already met with success in discovering novel trait-gene associations for other complex traits. Here, we use exome sequencing to investigate the effects of rare variants on general cognitive ability. Unrelated Scottish individuals were selected for high scores on a general component of intelligence (g). The frequency of rare genetic variants (in n = 146) was compared with those from Scottish controls (total n = 486) who scored in the lower to middle range of the g distribution or on a proxy measure of g. Biological pathway analysis highlighted enrichment of the mitochondrial inner membrane component and apical part of cell gene ontology terms. Global burden analysis showed a greater total number of rare variants carried by high g cases versus controls, which is inconsistent with a mutation load hypothesis whereby mutations negatively affect g. The general finding of greater non-synonymous (vs. synonymous) variant effects is in line with evolutionary hypotheses for g. Given that this first sequencing study of high g was small, promising results were found, suggesting that the study of rare variants in larger samples would be worthwhile.
Entwicklung und Evaluation einer internetbasierten begleiteten Selbsthilfe-Intervention zur Bewältigung von Albträumen
Authors: Böckermann Max , Gieselmann Annika , Sorbi Marjolijn , Pietrowsky Reinhard
Published: March 2015

Hintergrund: Dieser Artikel beschreibt die Entwicklung eines internetbasierten begleiteten Selbsthilfetrainings (Albtraumcoach) zur Bewältigung von Albträumen, das innerhalb zweier Pilotstudien auf seine Durchführbarkeit und Anwendbarkeit getestet wurde. Methoden: Innerhalb eines neunstufigen Modells wird die Entwicklung der Intervention beschrieben. Dabei wird neben der wissenschaftlichen Evidenz, die die Basis für die Intervention bildet, auf technische, ethische, datenschutzrechtliche und weitere spezifische Maßnahmen innerhalb der Interventionsentwicklung eingegangen. In zwei Pilotstudien evaluierten zudem 10 Personen mit schlechten Träumen in der Vergangenheit die Durchführbarkeit (Studie 1) und 12 Personen mit wiederkehrenden Albträumen die Anwendbarkeit sowie den Nutzen der Intervention (Studie 2). Abhängige Variablen waren die Qualität der einzelnen Sitzungen, die Zufriedenheit mit der Intervention sowie Albtraumfrequenz, Albtraumbelastung, Schlafqualität und Depressivität. Ergebnisse und Diskussion: Die Durchführbarkeit und Anwendbarkeit des Trainings wurden positiv beurteilt. Während die Drop-out-Rate verhältnismäßig hoch war, ergaben sich erste, zurückhaltend zu beurteilende, Hinweise für einen Nutzen der Intervention.
Stereochemical bias introduced during RNA synthesis modulates the activity of phosphorothioate siRNAs
Authors: Jahns Hartmut , Roos Martina , Imig Jochen , Baumann Fabienne , Wang Yuluan , Gilmour Ryan , Hall Jonathan
Published: March 2015

An established means of improving the pharmacokinetics properties of oligoribonucleotides (ORNs) is to exchange their phosphodiester linkages for phosphorothioates (PSs). However, this strategy has not been pursued for small interfering RNAs (siRNAs), possibly because of sporadic reports that PS siRNAs show reduced inhibitory activity. The PS group is chiral at phosphorous (Rp/Sp centres), and conventional solid-phase synthesis of PS ORNs produces a population of diastereoisomers. Here we show that the choice of the activating agent for the synthesis of a PS ORN influences theRp/Sp ratio of PS linkages throughout the strand. Furthermore, PS siRNAs composed of ORNs with a higher fraction ofRp centres show greater resistance to nucleases in serum and are more effective inhibitors in cells than theirSp counterparts. The finding that a stereochemically biased population of ORN diastereoisomers can be synthesized and exploited pharmacologically is important because uniform PS modification of siRNAs may provide a useful compromise of their pharmacokinetics and pharmacodynamics properties in RNAi therapeutics.
Switching from Visibility to Invisibility via Fano Resonances: Theory and Experiment
Authors: Rybin Mikhail V. , Filonov Dmitry S. , Belov Pavel A. , Kivshar Yuri S. , Limonov Mikhail F.
Published: March 2015

Subwavelength structures demonstrate many unusual optical properties which can be employed for engineering of a new generation of functional metadevices, as well as controlled scattering of light and invisibility cloaking. Here we demonstrate that the suppression of light scattering for any direction of observation can be achieved for a uniform dielectric object with high refractive index, in a sharp contrast to the cloaking with multilayered plasmonic structures suggested previously. Our finding is based on the novel physics of cascades of Fano resonances observed in the Mie scattering from a homogeneous dielectric rod. We observe this effect experimentally at microwaves by employing high temperature-dependent dielectric permittivity of a glass cylinder with heated water. Our results open a new avenue in analyzing the optical response of high-index dielectric nanoparticles and the physics of cloaking.
Natural high pCO2 increases autotrophy in Anemonia viridis (Anthozoa) as revealed from stable isotope (C, N) analysis
Authors: Horwitz Rael , Borell Esther M. , Yam Ruth , Shemesh Aldo , Fine Maoz
Published: March 2015

Contemporary cnidarian-algae symbioses are challenged by increasing CO2concentrations (ocean warming and acidification) affecting organisms' biological performance. We examined the natural variability of carbon and nitrogen isotopes in the symbiotic sea anemoneAnemonia viridisto investigate dietary shifts (autotrophy/heterotrophy) along a naturalpCO2gradient at the island of Vulcano, Italy. δ13C values for both algal symbionts (Symbiodinium) and host tissue ofA. viridisbecame significantly lighter with increasing seawaterpCO2. Together with a decrease in the difference between δ13C values of both fractions at the higherpCO2sites, these results indicate there is a greater net autotrophic input to theA. viridiscarbon budget under highpCO2conditions. δ15N values and C/N ratios did not change inSymbiodiniumand host tissue along thepCO2gradient. Additional physiological parameters revealed anemone protein andSymbiodiniumchlorophyllaremained unaltered among sites.Symbiodiniumdensity was similar among sites yet their mitotic index increased in anemones under elevatedpCO2. Overall, our findings show thatA. viridisis characterized by a higher autotrophic/heterotrophic ratio aspCO2increases. The unique trophic flexibility of this species may give it a competitive advantage and enable its potential acclimation and ecological success in the future under increased ocean acidification.