bluuebunny/crossref_metadata_2025_split huggingface dataset:
New PARSEC database of alpha enhanced stellar evolutionary tracks and isochrones for Gaia
Authors: Fu Xiaoting , Bressan Alessandro , Marigo Paola , Girardi Léo , Montalban Josefina , Chen Yang , Nanni Ambra , Lanza Antonio 
Published: October 2016

AbstractWe present a new database of alpha enhanced evolutionary tracks and isochrones, computed with PARSEC (the PAdova & TRieste Stellar Evolution Code). The new isochrones are tested against Color-Magnitude Diagrams of well studied Globular Clusters, tacking into account multiple population effects. They are also compared with observations of dwarf stars in the Solar vicinity. After these preliminary computations, we will provide the full sets of isochrones with chemical compositions suitable for Globular Clusters and Bulge stars, that will be fully implemented into galaxy simulators. We will also provide new models suitable for the analysis of unresolved stellar populations in early type galaxies.
Spectroscopy with Three-Dimensional Model Atmospheres of Late-Type Stars
Authors: Collet Remo 
Published: October 2016

AbstractIn this contribution, I present the results of a differential analysis of CH spectral lines for the determination of carbon abundances with three- and one-dimensional model atmospheres of late-type stars at various metallicities. 3D-1D abundance corrections are found to be significant particularly at low metallicities and for turn-off stars. The dependence of 3D-1D carbon abundance corrections on the stellar C/O ratio is also discussed.
Monash Chemical Yields Project (Monχey) Element production in low- and intermediate-mass stars
Authors: Doherty Carolyn , Lattanzio John , Angelou George , Campbell Simon W. , Church Ross , Constantino Thomas , Cristallo Sergio , Gil-Pons Pilar , Karakas Amanda , Lugaro Maria , Stancliffe Richard 
Published: October 2016

AbstractThe Monχey project will provide a large and homogeneous set of stellar yields for the low- and intermediate- mass stars and has applications particularly to galactic chemical evolution modelling. We describe our detailed grid of stellar evolutionary models and corresponding nucleosynthetic yields for stars of initial mass 0.8 M⊙ up to the limit for core collapse supernova (CC-SN) ≈ 10 M⊙. Our study covers a broad range of metallicities, ranging from the first, primordial stars (Z = 0) to those of super-solar metallicity (Z = 0.04). The models are evolved from the zero-age main-sequence until the end of the asymptotic giant branch (AGB) and the nucleosynthesis calculations include all elements from H to Bi. A major innovation of our work is the first complete grid of heavy element nucleosynthetic predictions for primordial AGB stars as well as the inclusion of extra-mixing processes (in this case thermohaline) during the red giant branch. We provide a broad overview of our results with implications for galactic chemical evolution as well as highlight interesting results such as heavy element production in dredge-out events of super-AGB stars. We briefly introduce our forthcoming web-based database which provides the evolutionary tracks, structural properties, internal/surface nucleosynthetic compositions and stellar yields. Our web interface includes user- driven plotting capabilities with output available in a range of formats. Our nucleosynthetic results will be available for further use in post processing calculations for dust production yields.
Dust and Metallicity across local Galaxies
Authors: Groves Brent 
Published: October 2016

AbstractThe gas-phase metallicity is one of the key insights we have into measuring the chemical feedback of stars in galaxies, yet remains difficult to correctly determine. However, there is a close relation between gas-phase metals and dust in the ISM, which can give us insight into the correct metallicity in galaxies. Here I will present recent work on metallicity gradients in galaxies, and how we can measure the global metallicity and the radial gradients in nearby galaxies using dust, through the dust-to-gas ratio.
The global oxygen yield budget followed in hydrodynamic simulations
Authors: Oppenheimer Benjamin D. , Crain Robert A. , Schaye Joop , Tumlinson Jason 
Published: October 2016

AbstractWe present new EAGLE (“Evolution and Assembly of GaLaxies and their Environments”, Schaye et al. 2015) zoom simulations of a range of Milky Way-like galaxies that can uniquely reproduce the metallicities of galactic stars, the ISM, and now the circumgalactic medium (CGM) as probed by quasar absorption line surveys. The surprising result is that the average L* galaxy loses more oxygen to the CGM out to hundreds of kpcs from a galaxy than it retains in its stars. These zooms not only follow the nucleosynthetic yields of 11 elements, they follow the non-equilibrium ionization and cooling of 133 ions, which allow direct comparison to observations of the COS-Halos survey of O VI in galactic halos out to 150 kpc (Tumlinson et al. 2011). The result is a new understanding of the galactic nucleosynthetic yield budget in simulations where galaxies are dramatically shaped by supernovae and black hole feedback. We are now closer to reconciling observed stellar, ISM, and now CGM metallicities with the nucleosynthetic production of the stellar component.
The evolution of dust in the local and high-redshift universe
Authors: Dwek Eli , Arendt Richard G. , Staguhn Johannes , Temim Tea 
Published: October 2016

AbstractDust is a ubiquities component of the interstellar medium (ISM) of galaxies, and manifests itself in many different ways. Yet, its origin, composition, and size distribution are still a matter of great debate. Most of the thermally condensed dust is produced in the explosively expelled ejecta of core collapse supernovae (CCSNe) and in the quiescent winds of AGB stars. Following its injection into the ISM it is destroyed by supernova (SN) shock waves. Knowing the relative rates of these processes is crucial for understanding the nature and evolution of dust in galaxies. In the following we will review three aspects of the evolution of dust in galaxies: the evolution of dust in the ejecta of SN1987A; the rates of dust production and destruction rates in the Magellanic Clouds (MCs), and the evolution of dust in CLASH 2882, a gravitationally-lensed galaxy at z=1.
Studying Supernovae under the Current Paradigm
Authors: Fryer Chris L. 
Published: October 2016

AbstractThe convection-enhanced paradigm behind core-collapse supernovae (SNe) invokes a multi-physics model where convection above the proto-neutron star is able to convert the energy released in the collapse to produce the violent explosions observed as SNe. Over the past decade, the evidence in support of this engine has grown, including constraints placed by SN neutrinos, energies, progenitors and remnants. Although considerable theoretical work remains to utilize this data, our understanding of normal SNe is advancing. To achieve a deeper level of understanding, we must find ways to compare detailed simulations with the increasing set of observational data. Here we review the current constraints and how we can apply our current understanding to broaden our understanding of these powerful engines.
Metallicity dependence of Type Ib/c and IIb supernova progenitors in binary systems
Authors: Yoon Sung-Chul 
Published: October 2016

AbstractType Ib/c supernovae (SNe Ib/c) are characterized by the lack of prominent hydrogen lines in thespectra, implying that their progenitors have lost most of their hydrogen envelopes by the time of the iron corecollapse. Binary interactions provide an important evolutionary chanel for SNe Ib/c, and recent observations indicatethat the inferred ejecta masses of SNe Ibc are more consistent with the prediction of the binary scenario than that ofthe single star scenario that invokes mass loss as the key evolutionary factor for SNe Ib/c progenitors. So far,theoretical predictions on the detailed properties of SNe Ib/c progenitors in binary systems have been made mostlywith models using solar metallicity. However, unlike the single star scenario, where SNe Ib/c are expected only forsufficiently high metallicity, hydrogen-deficent SN progenitors can be produced via binary interactions at anymetallicity. In this talk, I will discuss theoretical predictions on the metallicity dependence of the SNe Ib/c progenitorstructure, based on evolutionary models of massive binary stars. Sepefically, I will address how the ejecta masses ofSNe Ib and Ic and the ratio of SN Ib/c to SN IIb as well as SN Ib to SN Ic would systematically change as a function ofmetallicity, and which new types of SNe are expected in binary systems at low metallicity.
Determining the progenitors of supernovae with early robotic observations
Authors: Howell Andrew 
Published: October 2016

AbstractWe present results from the LCOGT Supernova Key Project, a three year program to obtain lightcurves and spectra of 600 supernovae. The Las Cumbres Observatory Global Telescope Network is a network of eleven robotic 1m and 2m telescopes located at 5 sites around the world. With this facility long term monitoring of transient phenomena is possible, as are nearly instantaneous observations. We report on both core-collapse and thermonuclear supernovae observed within days of explosion, allowing insight into their progenitor stars.
A Spitzer Search for the Missing Supernovae in the Galactic Nuclei of ULIRGS
Authors: Fox Ori D. , Casper Chad 
Published: October 2016

AbstractSupernova (SN) rates serve as an important probe of star formation models and initial mass functions, particularly at high redshifts due to the SN intrinsic luminosity. Ground-based optical surveys, however, typically discover nearly ten times fewer SNe than predicted, challenging our understanding of massive star formation and evolution. These results are generally attributed to the high dust extinction associated with the nuclei of star forming galaxies, such as Ultra Luminous InfraRed Galaxies (ULIRGs). Near-infrared surveys have been unsuccessful due to extinction values exceeding AV > 25 mag, and even on an 8-m AO system, subtraction algorithms used to find the SNe inevitably leave large residuals associated with the inner 2” of the galactic nucleus, which is where a majority of the SNe occur. A successful survey must be conducted at longer wavelengths and with a space-based telescope, which has stable seeing that reduces the necessity for any subtraction algorithms and, therefore, residuals. Here we present ongoing work from our 300 hour Spitzer 3.6 micron survey for dust-extinguished SNe in the nuclear regions of ULIRGs within 200 Mpc. The direct product of this study will be an improved understanding of the connection between the far-IR luminosity of ULIRGs and massive star formation.
Magnetar-driven explosions as power source of Gamma-ray Bursts and Supernovae
Authors: Olivares E. Felipe , Greiner Jochen 
Published: October 2016

AbstractWe present photometry and spectroscopy of SN 2011kl associated to GRB 111209A. Peculiarities arise from both the ultra-long GRB and the very luminous SN, brighter than any other GRB-associated SN observed to date. We present unequivocal evidence in favor of a scenario where a newly-formed magnetar powers both the GRB and the SN.
Resolved Host Studies of Stellar Explosions
Authors: Levesque Emily M. 
Published: October 2016

AbstractThe host galaxies of nearby (z<0.3) core-collapse supernovae and long-duration gamma-ray bursts offer an excellent means of probing the environments and populations that produce these events' varied massive progenitors. These same young stellar progenitors make LGRBs and SNe valuable and potentially powerful tracers of star formation, metallicity, the IMF, and the end phases of stellar evolution. However, properly utilizing these progenitors as tools requires a thorough understanding of their formation and, consequently, the physical properties of their parent host environments. In this talk I will review some of the recent work on LGRB and SN hosts with resolved environments that allows us to probe the precise explosion sites and surrounding environments of these events in incredible detail.
Dual Active Galactic Nuclei
Authors: Greene Jenny E. , Mueller-Sanchez Fransisco , Comerford Julia M. 
Published: October 2016

AbstractWe still do not know the timescale for the merging of binary black holes (BHs). This timescale has important implications for gravitational wave predictions and our understanding of BH demographics. Here we discuss efforts to constrain the fraction of BH pairs on kpc scales using observations of dual active galactic nuclei.
Environment and Galaxy Host Properties of PTA and eLISA Sources
Authors: Palafox Eva Martínez , Valenzuela Octavio , Colín Pedro , Gottlöber Stefan 
Published: October 2016

AbstractWe use a dynamical model for the decay of supermassive black hole binaries (BHBs) coupled with a cosmological simulation and semi-empirical approaches to the occupation of halos by galaxies and BHs, in order to investigate the properties of galaxies hosting BHBs. We found bimodal distributions of hosts properties, with one peak corresponding to BHBs suitable to be detected by PTAs and the other to BHBs in the eLISA frequency window. We note that for some of the scenarios explored there must be a considerable population of such sources in the nearby Universe that might show detectable EM signatures, representing an important laboratory for multimessenger astrophysics.
Pulsar Timing Arrays
Authors: McLaughlin Maura 
Published: October 2016

AbstractI describe the concept of a pulsar timing array and give broad overview of the construction of a pulsar timing array, methods for high-precision timing and noise characterization, and algorithms for gravitational wave detection and source characterization. I then provide an overview of worldwide pulsar timing programs and the scale and sensitivity of the pulsar timing array efforts, with particular attention to the International Pulsar Timing Array (IPTA). I discuss the most recent results from pulsar timing arrays, emphasizing the gravitational wave detection efforts in particular. Finally, I describe the anticipated future growth in participants, telescopes, pulsars, and sensitivity of the IPTA, highlighting the transformational advances that it will enable over the next decade.
Asteroseismology of Red-Giant Stars as a Novel Approach in the Search for Gravitational Waves
Authors: Campante Tiago L. , Lopes Ilídio , Bossini D. , Miglio A. , Chaplin W. J. 
Published: October 2016

AbstractStars are massive resonators that may be used as gravitational-wave (GW) detectors with isotropic sensitivity. New insights on stellar physics are being made possible by asteroseismology, the study of stars by the observation of their natural oscillations. The continuous monitoring of oscillation modes in stars of different masses and sizes (e.g., as carried out by NASA's Kepler mission) opens the possibility of surveying the local Universe for GW radiation. Red-giant stars are of particular interest in this regard. Since the mean separation between red giants in open clusters is small (a few light years), this can in principle be used to look for the same GW imprint on the oscillation modes of different stars as a GW propagates across the cluster. Furthermore, the frequency range probed by oscillations in red giants complements the capabilities of the planned eLISA space interferometer. We propose asteroseismology of red giants as a novel approach in the search for gravitational waves.
Water and organics in interplanetary dust particles
Authors: Bradley John 
Published: October 2016

AbstractInterplanetary dust particles (IDPs) and larger micrometeorites (MMs) impinge on the upper atmosphere where they decelerate at 90 km altitude and settle to the Earths surface. Comets and asteroids are the major sources and the flux, 30,000-40,000 tons/yr, is comparable to the mass of larger meteorites impacting the Earths surface. The sedimentary record suggests that the flux was much higher on the early Earth. The chondritic porous (CP) subset of IDPs together with their larger counterparts, ultracarbonaceous micrometeorites (UCMMs), appear to be unique among known meteoritic materials in that they are composed almost exclusively of anhydrous minerals, some of them contain >> 50% organic carbon by volume as well as the highest abundances of presolar silicate grains including GEMS. D/H and 15N abundances implicate the Oort Cloud or presolar molecular cloud as likely sources of the organic carbon. Prior to atmospheric entry, IDPs and MMs spend 104-105 year lifetimes in solar orbit where their surfaces develop amorphous space weathered rims from exposure to the solar wind (SW). Similar rims are observed on lunar soil grains and on asteroid Itokawa regolith grains. Using valence electron energy-loss spectroscopy (VEELS) we have detected radiolytic water in the rims on IDPs formed by the interaction of solar wind protons with oxygen in silicate minerals. Therefore, IDPs and MMs continuously deliver both water and organics to the earth and other terrestrial planets. The interaction of protons with oxygen-rich minerals to form water is a universal process.
Forming terrestrial planets and delivering water
Authors: Walsh Kevin J. 
Published: October 2016

AbstractBuilding models capable of successfully matching the Terrestrial Planet's basic orbital and physical properties has proven difficult. Meanwhile, improved estimates of the nature of water-rich material accreted by the Earth, along with the timing of its delivery, have added even more constraints for models to match. While the outer Asteroid Belt seemingly provides a source for water-rich planetesimals, models that delivered enough of them to the still-forming Terrestrial Planets typically failed on other basic constraints - such as the mass of Mars.Recent models of Terrestrial Planet Formation have explored how the gas-driven migration of the Giant Planets can solve long-standing issues with the Earth/Mars size ratio. This model is forced to reproduce the orbital and taxonomic distribution of bodies in the Asteroid Belt from a much wider range of semimajor axis than previously considered. In doing so, it also provides a mechanism to feed planetesimals from between and beyond the Giant Planet formation region to the still-forming Terrestrial Planets.
Type II supernova diversity
Authors: Anderson Joseph P. 
Published: October 2016

AbstractIt is now firmly established that at a significant fraction of hydrogen-rich type II supernovae (SNe II) arise from red supergiant progenitors. However, a large diversity of SN properties exist, and it is presently unclear how this can be understood in terms of progenitor differences and pre-SN stellar evolution. In this contribution, I present the diversity of SN II V-band light-curves for a large sample of SNe II, and compare these to photometry of SNe II which have progenitor mass constraints from pre-explosion imaging.
Chromospheres of Luminous Cool Stars
Authors: Dupree A. K. 
Published: October 2016

AbstractDirect ultraviolet imaging and spectroscopy of Alpha Orionis (Betelgeuse) reveals variable chromospheric structures and mass motions. Spectroscopy also demonstrates the changes of wind opacity, speeds, and mass loss in luminous stars. Cool stars have complex chromospheres that need to be considered in construction of stellar atmospheric models and subsequent spectral analyses.
On the Explosion Geometry of Red Supergiant Stars
Authors: Leonard Douglas C. , Dessart Luc , Pignata Giuliano , Hillier D. John , Williams George G. , Smith Paul S. , Khandrika Harish , Bilinski Christopher , Duong Nhieu , Flatland Kelsi , Gonzalez Luis , Hoffman Jennifer L. , Horst Chuck , Huk Leah , Milne Peter , Rachubo Alisa A. , Smith Nathan 
Published: October 2016

AbstractWe present the observed “continuum” levels of polarization as a function of time for four well-observed Type II-Plateau supernovae (SNe II-P; Fig. 1), the class of SNe decisively determined to arise from red supergiant stars (Smartt 2009). All four objects show temporally increasing degrees of polarization through the end of the photospheric phase, with some exhibiting early-time polarization that challenge existing models (e.g., Dessart and Hillier 2011) to reproduce. A fundamental ejecta asymmetry is present in this photometrically diverse sample of type II SNe, and it probably takes different forms (e.g., 56Ni blobs/fingers, large scale deformation). We acknowledge support from NSF grants AST-1009571 and AST-1210311.
The chemical composition of β Cephei and hybrid pulsators in the solar neighbourhood
Authors: Przybilla Norbert , Nieva Maria-Fernanda 
Published: October 2016

Abstractβ Cephei variables are the most prominent pulsators among the massive stars on the upper main sequence, extending into the class of the rare hybrid β Cephei-SPB pulsators in the overlap region with the instability strip of the Slowly Pulsating B-stars. While the κ-mechanism has been identified as the driver of the pulsations, a comprehensive explanation of the excitation of the observed p- and g-modes is still lacking. In particular, the instability regions for these main-sequence B-type pulsators are still not fully consistent with any current opacity calculations. We have determined tight observational constraints on the chemical composition of a sample of β Cephei and hybrid pulsators in the solar neighbourhood, covering all elements with abundances log (X/H) + 12 > 7.3. The star sample turns out to be chemically homogeneous, with a metallicity Z ≈ 0.014 and a non-solar abundance mix. The availability of accurate and precise abundances eliminates one of the two variables in the opacity calculations for asteroseismic applications, allowing to focus on (missing) atomic data.
Constraining the physics of carbon crystallization through pulsations of a massive DAV BPM37093
Authors: Nitta Atsuko , Kepler S. O. , Chené André-Nicolas , Koester D. , Provencal J. L. , Kleinmani S. J. , Sullivan D. J. , Chote Paul , Sefako Ramotholo , Kanaan Antonio , Romero Alejandra , Corti Mariela , Kilic Mukremin , Montgomery M. H. , Winget D. E. 
Published: October 2016

AbstractWe are trying to reduce the largest uncertainties in using white dwarf stars as Galactic chronometers by understanding the details of carbon crystalliazation that currently result in a 1–2 Gyr uncertainty in the ages of the oldest white dwarf stars. We expect the coolest white dwarf stars to have crystallized interiors, but theory also predicts hotter white dwarf stars, if they are massive enough, will also have some core crystallization. BPM 37093 is the first discovered of only a handful of known massive white dwarf stars that are also pulsating DAV, or ZZ Ceti, variables. Our approach is to use the pulsations to constrain the core composition and amount of crystallization. Here we report our analysis of 4 hours of continuous time series spectroscopy of BPM 37093 with Gemini South combined with simultaneous time-series photometry from Mt. John (New Zealand), SAAO, PROMPT, and Complejo Astronomico El Leoncito (CASLEO, Argentina).
Time-domain survey of the Galactic anti-center using Nanshan 1m telescope
Authors: Yang T.-Z. , Esamdin A. , Fu J.-N. , Ma L. , Liu J.-Z. , Song F.-F. 
Published: October 2016

AbstractFollowing the LAMOST Spectroscopic Survey and Xuyi's Photometric Survey of the Galactic anti-center (GAC), we plan to conduct a time-domain survey of GAC to study the variable sky using Nanshan 1m telescope. The survey will be conducted during winter (in Nov., Dec., and Jan.). The first goal of the survey is to cover 270 sq.deg. of sky area in three years. The survey intends to detect some strong transient events of stars and find some short time-scale variable stars of different types. In this paper, we introduce the survey and present the preliminary results already carried out.