RAS_WEB (Page 2,842)

The landscape of disk outflows from black hole – neutron star mergers. (arXiv:2005.14208v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Fernandez_R/0/1/0/all/0/1">Rodrigo Fern&#xe1;ndez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Foucart_F/0/1/0/all/0/1">Francois Foucart</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lippuner_J/0/1/0/all/0/1">Jonas Lippuner</a> We investigate mass ejection from accretion disks formed in mergers of black holes (BHs) and neutron stars (NSs). The third observing run of the LIGO/Virgo interferometers provided BH-NS candidate events that yielded no electromagnetic (EM) counterparts. The broad range of disk configurations expected from BH-NS mergers motivates a thorough exploration of parameter space to improve EM signal predictions. Here we conduct 27 high-resolution, axisymmetric, long-term hydrodynamic simulations of the viscous evolution of black hole accretion disks that include neutrino emission/absorption effects andRead More →

On Lithium-6 as diagnostic of the lithium-enrichment mechanism in red giants. (arXiv:2005.14209v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Aguilera_Gomez_C/0/1/0/all/0/1">Claudia Aguilera-G&#xf3;mez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chaname_J/0/1/0/all/0/1">Julio Chanam&#xe9;</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pinsonneault_M/0/1/0/all/0/1">Marc H. Pinsonneault</a> High lithium-7 ($mathrm{^7Li}$) abundances in giants are indicative of non-standard physical processes affecting the star. Mechanisms that could produce this signature include contamination from an external source, such as planets, or internal production and subsequent mixing to the stellar surface. However, distinguishing between different families of solutions has proven challenging, and there is no current consensus model that explains all the data. The lithium-6 ($mathrm{^6Li}$) abundance may be a potentially important discriminant, as the relative $mathrm{^6Li}$ and $mathrm{^7Li}$ abundances are expected toRead More →

Maximal extension of the Schwarzschild metric: From Painlev’e-Gullstrand to Kruskal-Szekeres. (arXiv:2005.14211v1 [gr-qc]) <a href="http://arxiv.org/find/gr-qc/1/au:+Lemos_J/0/1/0/all/0/1">Jos&#xe9; P. S. Lemos</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Silva_D/0/1/0/all/0/1">Diogo L. F. G. Silva</a> We find a specific coordinate system that goes from the Painlev’e-Gullstrand partial extension to the Kruskal-Szekeres maximal extension and thus exhibit the maximal extension of the Schwarzschild metric in a unified picture. We do this by adopting two time coordinates, one being the proper time of a congruence of outgoing timelike geodesics, the other being the proper time of a congruence of ingoing timelike geodesics, both parameterized by the same energy per unit mass $E$. $E$ is in the range $1leq E<infty$Read More →

Super-Penrose process for extremal rotating neutral white holes. (arXiv:2005.14241v1 [gr-qc]) <a href="http://arxiv.org/find/gr-qc/1/au:+Zaslavskii_O/0/1/0/all/0/1">O. B. Zaslavskii</a> We consider collision of two particles 1 and 2 near the horizon of the extremal rotating axially symmetric neutral generic black hole producing particles 3 and 4. We discuss the scenario in which both particles 3 and 4 fall into a black hole and move in a white hole region. If particle 1 is fine-tuned, the energy $E_{c.m.}$ in the centre of mass grows unbounded (the Ba~{n}ados-Silk-West effect). Then, particle 3 can, in principle, reach a flat infinity in another universe. If not only $E_{c.m.}$ but also the corresponding Killing energyRead More →

A Plasmoid Model for the Sgr A* Flares Observed with GRAVITY and Chandra. (arXiv:2005.14251v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Ball_D/0/1/0/all/0/1">David Ball</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ozel_F/0/1/0/all/0/1">Feryal &#xd6;zel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Christian_P/0/1/0/all/0/1">Pierre Christian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chan_C/0/1/0/all/0/1">Chi-Kwan Chan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Psaltis_D/0/1/0/all/0/1">Dimitrios Psaltis</a> The Galactic Center black hole Sgr A* shows significant variability and flares in the submillimeter, infrared, and X-ray wavelengths. Owing to its exquisite resolution in the IR bands, the GRAVITY experiment for the first time spatially resolved the locations of three flares and showed that a bright region moves in ellipse-like trajectories close to but offset from the black hole over the course of each event. We present a model for plasmoids that form duringRead More →

Revisiting the distance to the nearest UHECR source: Effects of extra-galactic magnetic fields. (arXiv:2005.14275v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Lang_R/0/1/0/all/0/1">Rodrigo Guedes Lang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Taylor_A/0/1/0/all/0/1">Andrew M. Taylor</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ahlers_M/0/1/0/all/0/1">Markus Ahlers</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Souza_V/0/1/0/all/0/1">Vitor de Souza</a> We update the constraints on the location of the nearest UHECR source. By analyzing recent data from the Pierre Auger Observatory using start-of-the-art CR propagation models, we reaffirm the need of local sources with a distance less than 25-100~Mpc, depending on mass composition. A new fast semi-analytical method for the propagation of UHECR in environments with turbulent magnetic fields is developed. The onset of an enhancement and a low-energy magnetic horizon of cosmic rays fromRead More →

Planetary nebulae with Wolf-Rayet-type central stars — I. The case of the high-excitation NGC 2371. (arXiv:2005.14294v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Gomez_Gonzalez_V/0/1/0/all/0/1">V. M. A. G&#xf3;mez-Gonz&#xe1;lez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Toala_J/0/1/0/all/0/1">J. A. Toal&#xe1;</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guerrero_M/0/1/0/all/0/1">M. A. Guerrero</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Todt_H/0/1/0/all/0/1">H. Todt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sabin_L/0/1/0/all/0/1">L. Sabin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ramos_Larios_G/0/1/0/all/0/1">G. Ramos-Larios</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mayya_Y/0/1/0/all/0/1">Y. D. Mayya</a> We present the analysis of the planetary nebula (PN) NGC 2371 around the [Wolf-Rayet] ([WR]) star WD 0722$+$295. Our Isaac Newton Telescope (INT) Intermediate Dispersion Spectrograph (IDS) spectra, in conjunction with archival optical and UV images, unveil in unprecedented detail the high-ionisation of NGC 2371. The nebula has an apparent multipolar morphology, with two pairs of lobes protruding from a barrel-like centralRead More →

Possible Electromagnetic Phenomena during the Coalescence of Neutron Star-Black Hole Binary Systems. (arXiv:2005.14309v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Postnov_K/0/1/0/all/0/1">K. A. Postnov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kuranov_A/0/1/0/all/0/1">A. G. Kuranov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Simkin_I/0/1/0/all/0/1">I. V. Simkin</a> (Sternberg Astronomical Institute, Moscow) Possible models for the generation of electromagnetic (EM) radiation during the coalescence of neutron star-black hole binaries are considered. The mass of the remnant disk around the black hole during the coalescence of neutron stars and black holes is calculated by taking into account the equation of state for neutron stars and the rotation of the binary components before the coalescence. The parameters of binary systems before the coalescence (the mass ratio, the component rotation,Read More →

The interpretation of protoplanetary disc wind diagnostic lines from X-ray photoevaporation and analytical MHD models. (arXiv:2005.14312v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Weber_M/0/1/0/all/0/1">Michael L. Weber</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ercolano_B/0/1/0/all/0/1">Barbara Ercolano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Picogna_G/0/1/0/all/0/1">Giovanni Picogna</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hartmann_L/0/1/0/all/0/1">Lee Hartmann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rodenkirch_P/0/1/0/all/0/1">Peter J. Rodenkirch</a> High resolution spectra of typical wind diagnostics ([OI] 6300 r{A} and other forbidden emission lines) can often be decomposed into multiple components: high-velocity components with blueshifts up to several 100 km/s are usually attributed to fast jets, while narrow (NLVC) and broad (BLVC) low-velocity components are believed to trace slower disc winds. Under the assumption that the line-broadening is dominated by Keplerian rotation, several studies have found that the BLVCs shouldRead More →

Magnetohydrostatic modeling of AR11768 based on a SUNRISE/IMaX vector magnetogram. (arXiv:2005.14332v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Zhu_X/0/1/0/all/0/1">Xiaoshuai Zhu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wiegelmann_T/0/1/0/all/0/1">Thomas Wiegelmann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Solanki_S/0/1/0/all/0/1">Sami Solanki</a> Context. High resolution magnetic field measurements are routinely done only in the solar photosphere. Higher layers like the chromosphere and corona can be modeled by extrapolating the photospheric magnetic field upward. In the solar corona, plasma forces can be neglected and the Lorentz force vanishes. This is not the case in the upper photosphere and chromosphere where magnetic and non-magnetic forces are equally important. One way to deal with this problem is to compute the plasma and magnetic field self-consistently with a magnetohydrostatic (MHS)Read More →

Testing gravity using galaxy-galaxy lensing and clustering amplitudes in KiDS-1000, BOSS and 2dFLenS. (arXiv:2005.14351v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Blake_C/0/1/0/all/0/1">Chris Blake</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Amon_A/0/1/0/all/0/1">Alexandra Amon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Asgari_M/0/1/0/all/0/1">Marika Asgari</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bilicki_M/0/1/0/all/0/1">Maciej Bilicki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dvornik_A/0/1/0/all/0/1">Andrej Dvornik</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Erben_T/0/1/0/all/0/1">Thomas Erben</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Giblin_B/0/1/0/all/0/1">Benjamin Giblin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Glazebrook_K/0/1/0/all/0/1">Karl Glazebrook</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Heymans_C/0/1/0/all/0/1">Catherine Heymans</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hildebrandt_H/0/1/0/all/0/1">Hendrik Hildebrandt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Joachimi_B/0/1/0/all/0/1">Benjamin Joachimi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Joudaki_S/0/1/0/all/0/1">Shahab Joudaki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kannawadi_A/0/1/0/all/0/1">Arun Kannawadi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kuijken_K/0/1/0/all/0/1">Konrad Kuijken</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lidman_C/0/1/0/all/0/1">Chris Lidman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Parkinson_D/0/1/0/all/0/1">David Parkinson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shan_H/0/1/0/all/0/1">HuanYuan Shan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Troster_T/0/1/0/all/0/1">Tilman Tr&#xf6;ster</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Busch_J/0/1/0/all/0/1">Jan Luca van den Busch</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wolf_C/0/1/0/all/0/1">Christian Wolf</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wright_A/0/1/0/all/0/1">Angus H. Wright</a> The physics of gravity on cosmological scales affects both the rate of assembly of large-scale structure, and the gravitational lensing of background lightRead More →

On the evolution of Diagonal Ridge pattern found in Gaia DR2 with LAMOST Main-Sequence-Turn-Off and OB type Stars. (arXiv:2005.14362v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_H/0/1/0/all/0/1">H.-F. Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Huang_Y/0/1/0/all/0/1">Y. Huang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_H/0/1/0/all/0/1">H.-W. Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lopez_Corredoira_M/0/1/0/all/0/1">M.L&#xf3;pez-Corredoira</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_B/0/1/0/all/0/1">B.-Q. Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guo_R/0/1/0/all/0/1">R. Guo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chang_J/0/1/0/all/0/1">J. Chang</a> We revisit the diagonal ridge feature (diagonal distributions in the $R, v_{phi}$ plane) found in $Gaia$ and present timing analysis for it between Galactocentric distances of $R=7.5$ and 12 ,kpc, using Main-Sequence-Turn-Off and OB stars selected from the LAMOST Galactic spectroscopic surveys. We recover the ridge pattern in the $R$-$v_{phi}$ plane color coded by stellar number density and mean radial velocity and find this featureRead More →

The MeerKAT Telescope as a Pulsar Facility: System verification and early science results from MeerTime. (arXiv:2005.14366v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Bailes_M/0/1/0/all/0/1">M. Bailes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jameson_A/0/1/0/all/0/1">A. Jameson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Abbate_F/0/1/0/all/0/1">F. Abbate</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barr_E/0/1/0/all/0/1">E. D. Barr</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bhat_N/0/1/0/all/0/1">N. D. R. Bhat</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bondonneau_L/0/1/0/all/0/1">L. Bondonneau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Burgay_M/0/1/0/all/0/1">M. Burgay</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Buchner_S/0/1/0/all/0/1">S. J. Buchner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Camilo_F/0/1/0/all/0/1">F. Camilo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Champion_D/0/1/0/all/0/1">D. J. Champion</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cognard_I/0/1/0/all/0/1">I. Cognard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Demorest_P/0/1/0/all/0/1">P. B. Demorest</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Freire_P/0/1/0/all/0/1">P. C. C. Freire</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gautam_T/0/1/0/all/0/1">T. Gautam</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Geyer_M/0/1/0/all/0/1">M. Geyer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Griessmeier_J/0/1/0/all/0/1">J. M. Griessmeier</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guillemot_L/0/1/0/all/0/1">L. Guillemot</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hu_H/0/1/0/all/0/1">H. Hu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jankowski_F/0/1/0/all/0/1">F. Jankowski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Johnston_S/0/1/0/all/0/1">S. Johnston</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Karastergiou_A/0/1/0/all/0/1">A. Karastergiou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Karuppusamy_R/0/1/0/all/0/1">R. Karuppusamy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kaur_D/0/1/0/all/0/1">D. Kaur</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Keith_M/0/1/0/all/0/1">M. J. Keith</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kramer_M/0/1/0/all/0/1">M. Kramer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leeuwen_J/0/1/0/all/0/1">J. vanRead More →

Comparison of Image Scale Calibration Techniques: Known Pairs, Drift Scans and Aperture Grating. (arXiv:2005.14380v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+James_M/0/1/0/all/0/1">Matthew B. James</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+White_G/0/1/0/all/0/1">Graeme L. White</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bosi_S/0/1/0/all/0/1">Stephen G. Bosi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Letchford_R/0/1/0/all/0/1">Rod R. Letchford</a> We compared several techniques for calibrating angular separation between wide (>1 arcsec) pairs. These techniques are (i) reference pair calibration using {alpha} Cen AB orbital parameters, (ii) the video drift method, and (iii) the utilisation of an aperture diffraction grating with red filters of different passbands. Separations of 62 pairs were determined using these 3 calibration techniques and compared. It was found that {alpha} Cen AB and video drift methods are in good agreement.Read More →

Aquatic Biospheres On Temperate Planets Around Sun-like Stars And M-dwarfs. (arXiv:2005.14387v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Lingam_M/0/1/0/all/0/1">Manasvi Lingam</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Loeb_A/0/1/0/all/0/1">Abraham Loeb</a> Aquatic biospheres reliant on oxygenic photosynthesis are expected to play an important role on Earth-like planets with large-scale oceans insofar as carbon fixation (i.e., biosynthesis of organic compounds) is concerned. We investigate the properties of aquatic biospheres comprising Earth-like biota for habitable rocky planets orbiting Sun-like stars and late-type M-dwarfs such as TRAPPIST-1. In particular, we estimate how these characteristics evolve with the ambient ocean temperature ($T_W$), which is a key environmental variable. We show that many salient properties, such as the depth of the photosynthesis zoneRead More →

A plethora of new, magnetic chemically peculiar stars from LAMOST DR4. (arXiv:2005.14444v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Huemmerich_S/0/1/0/all/0/1">Stefan Huemmerich</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Paunzen_E/0/1/0/all/0/1">Ernst Paunzen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bernhard_K/0/1/0/all/0/1">Klaus Bernhard</a> Magnetic chemically peculiar (mCP) stars are important to astrophysics because their complex atmospheres lend themselves perfectly to the investigation of the interplay between such diverse phenomena as atomic diffusion, magnetic fields, and stellar rotation. The present work is aimed at identifying new mCP stars using spectra collected by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). Suitable candidates were selected by searching LAMOST DR4 spectra for the presence of the characteristic 5200A flux depression. Spectral classification was carried out with a modifiedRead More →

Cold, dry, windy, and UV irradiated — surveying Mars relevant conditions in Ojos del Salado Volcano (Andes Mountains, Chile). (arXiv:2005.14450v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Kereszturi_A/0/1/0/all/0/1">&#xc1;. Kereszturi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Aszalos_J/0/1/0/all/0/1">J. Aszal&#xf3;s</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Heiling_Z/0/1/0/all/0/1">Zs. Heiling</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kapui_Z/0/1/0/all/0/1">Zs. Kapui</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kiraly_C/0/1/0/all/0/1">Cs. Kir&#xe1;ly</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leel_Ossy_S/0/1/0/all/0/1">Sz. Le&#xe9;l-&#xd6;ssy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nagy_B/0/1/0/all/0/1">B. Nagy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nemerkenyi_Z/0/1/0/all/0/1">Zs. Nemerk&#xe9;nyi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pal_B/0/1/0/all/0/1">B. P&#xe1;l</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Skulteti_A/0/1/0/all/0/1">&#xc1;. Skult&#xe9;ti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Szalai_Z/0/1/0/all/0/1">Z. Szalai</a> The Special Collection of papers in this issue of Astrobiology provide an overview of the characteristics and potential for future exploration of the Ojos del Salado volcano, located in the Andes Mountains in front of the Atacama Desert in northern Chile. The main benefits of this site compared with others areRead More →

Abelian-Higgs cosmic string evolution with multiple GPUs. (arXiv:2005.14454v1 [physics.comp-ph]) <a href="http://arxiv.org/find/physics/1/au:+Correia_J/0/1/0/all/0/1">J. R. C. C. C. Correia</a>, <a href="http://arxiv.org/find/physics/1/au:+Martins_C/0/1/0/all/0/1">C. J. A. P. Martins</a> Topological defects form at cosmological phase transitions by the Kibble mechanism. Cosmic strings and superstrings can lead to particularly interesting astrophysical and cosmological consequences, but this study is is currently limited by the availability of accurate numerical simulations, which in turn is bottlenecked by hardware resources and computation time. Aiming to eliminate this bottleneck, in recent work we introduced and validated a GPU-accelerated evolution code for local Abelian-Higgs strings networks. While this leads to significant gains in speed, it is still limited byRead More →

Re-evaluation of the $^{22}$Ne($alpha,gamma$)$^{26}$Mg and $^{22}$Ne($alpha,n$)$^{25}$Mg reaction rates. (arXiv:2005.14482v1 [nucl-ex]) <a href="http://arxiv.org/find/nucl-ex/1/au:+Adsley_P/0/1/0/all/0/1">Philip Adsley</a>, <a href="http://arxiv.org/find/nucl-ex/1/au:+Battino_U/0/1/0/all/0/1">Umberto Battino</a>, <a href="http://arxiv.org/find/nucl-ex/1/au:+Best_A/0/1/0/all/0/1">Andreas Best</a>, <a href="http://arxiv.org/find/nucl-ex/1/au:+Caciolli_A/0/1/0/all/0/1">Antonio Caciolli</a>, <a href="http://arxiv.org/find/nucl-ex/1/au:+Guglielmetti_A/0/1/0/all/0/1">Alessandra Guglielmetti</a>, <a href="http://arxiv.org/find/nucl-ex/1/au:+Imbriani_G/0/1/0/all/0/1">Gianluca Imbriani</a>, <a href="http://arxiv.org/find/nucl-ex/1/au:+Jayatissa_H/0/1/0/all/0/1">Heshani Jayatissa</a>, <a href="http://arxiv.org/find/nucl-ex/1/au:+Cognata_M/0/1/0/all/0/1">Marco La Cognata</a>, <a href="http://arxiv.org/find/nucl-ex/1/au:+Lamia_L/0/1/0/all/0/1">Livio Lamia</a>, <a href="http://arxiv.org/find/nucl-ex/1/au:+Masha_E/0/1/0/all/0/1">Eliana Masha</a>, <a href="http://arxiv.org/find/nucl-ex/1/au:+Massimi_C/0/1/0/all/0/1">Cristian Massimi</a>, <a href="http://arxiv.org/find/nucl-ex/1/au:+Palmerini_S/0/1/0/all/0/1">Sara Palmerini</a>, <a href="http://arxiv.org/find/nucl-ex/1/au:+Tattersall_A/0/1/0/all/0/1">Ashley Tattersall</a>, <a href="http://arxiv.org/find/nucl-ex/1/au:+Hirschi_R/0/1/0/all/0/1">Raphael Hirschi</a> The competing $^{22}$Ne($alpha,gamma$)$^{26}$Mg and $^{22}$Ne($alpha,n$)$^{25}$Mg reactions control the production of neutrons for the weak $s$-process in massive and AGB stars. In both systems, the ratio between the corresponding reaction rates strongly impacts the total neutron budget and strongly influences the final nucleosynthesis. The $^{22}$Ne($alpha,gamma$)$^{26}$Mg and $^{22}$Ne($alpha,n$)$^{25}$Mg reaction rates was re-evaluated by usingRead More →

Accelerated particle beams in a 3D simulation of the quiet Sun. (arXiv:2005.14483v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Frogner_L/0/1/0/all/0/1">L. Frogner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gudiksen_B/0/1/0/all/0/1">B. V. Gudiksen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bakke_H/0/1/0/all/0/1">H. Bakke</a> Observational and theoretical evidence suggests that beams of accelerated particles are produced in flaring events of all sizes in the solar atmosphere, from X-class flares to nanoflares. Current models of such particles in flaring loops assume an isolated 1D atmosphere. A more realistic environment for modelling accelerated particles can be provided by 3D radiative magnetohydrodynamics codes. Here we present a simple model for particle acceleration and propagation in the context of a 3D simulation of the quiet solar atmosphere spanning from convectionRead More →