RAS_WEB (Page 4,070)

Can astrophysical neutrinos trace the origin of the detected ultra-high energy cosmic rays?. (arXiv:1911.05756v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Palladino_A/0/1/0/all/0/1">Andrea Palladino</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vliet_A/0/1/0/all/0/1">Arjen van Vliet</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Winter_W/0/1/0/all/0/1">Walter Winter</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Franckowiak_A/0/1/0/all/0/1">Anna Franckowiak</a> Since astrophysical neutrinos are produced in the interactions of cosmic rays, identifying the origin of cosmic rays using directional correlations with neutrinos is one of the most interesting possibilities of the field. For that purpose, especially the Ultra-High Energy Cosmic Rays (UHECRs) are promising, as they are deflected less by extragalactic and Galactic magnetic fields than cosmic rays at lower energies. However, photo-hadronic interactions of the UHECRs limit their horizon, while neutrinos do not interact over cosmologicalRead More →

Flyby-induced misalignments in planet-hosting discs. (arXiv:1911.05760v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Nealon_R/0/1/0/all/0/1">Rebecca Nealon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cuello_N/0/1/0/all/0/1">Nicol&#xe1;s Cuello</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Alexander_R/0/1/0/all/0/1">Richard Alexander</a> We now have several observational examples of misaligned broken protoplanetary discs, where the disc inner regions are strongly misaligned with respect to the outer disc. Current models suggest that this disc structure can be generated with an internal misaligned companion (stellar or planetary), but the occurrence rate of these currently unobserved companions remains unknown. Here we explore whether a strong misalignment between the inner and outer disc can be formed without such a companion. We consider a disc that has an existing gap — essentially separating the disc intoRead More →

Capturing Non-Gaussianity of the Large-Scale Structure with Weighted Skew-Spectra. (arXiv:1911.05763v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Dizgah_A/0/1/0/all/0/1">Azadeh Moradinezhad Dizgah</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lee_H/0/1/0/all/0/1">Hayden Lee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schmittfull_M/0/1/0/all/0/1">Marcel Schmittfull</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dvorkin_C/0/1/0/all/0/1">Cora Dvorkin</a> The forthcoming generation of wide-field galaxy surveys will probe larger volumes and galaxy densities, thus allowing for a much larger signal-to-noise ratio for higher-order clustering statistics, in particular the galaxy bispectrum. Extracting this information, however, is more challenging than using the power spectrum due to more complex theoretical modeling, as well as significant computational cost of evaluating the bispectrum signal and the error budget. To overcome these challenges, several proxy statistics have been proposed in the literature, which partially or fullyRead More →

Constraints on the Engines of Fast Radio Bursts. (arXiv:1911.05765v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Margalit_B/0/1/0/all/0/1">Ben Margalit</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Metzger_B/0/1/0/all/0/1">Brian D. Metzger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sironi_L/0/1/0/all/0/1">Lorenzo Sironi</a> We model the sample of fast radio bursts (FRB), including the newly discovered CHIME repeaters, using the synchrotron blast wave model of Metzger, Margalit & Sironi (2019). This model postulates that FRBs are precursor radiation from ultra-relativistic magnetized shocks generated as flare ejecta from a central engine collide with an effectively stationary external medium. Downward drifting of the burst frequency structure naturally arises from deceleration of the blast-wave. The data are consistent with FRBs being produced by flares of energy $E_{rm flare} sim 10^{43}-10^{46}(f_{xi}/10^{-3})^{-4/5}$ erg,Read More →

ADMX SLIC: Results from a Superconducting LC Circuit Investigating Cold Axions. (arXiv:1911.05772v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Crisosto_N/0/1/0/all/0/1">N. Crisosto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rybka_G/0/1/0/all/0/1">G. Rybka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sikivie_P/0/1/0/all/0/1">P. Sikivie</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sullivan_N/0/1/0/all/0/1">N. S. Sullivan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tanner_D/0/1/0/all/0/1">D. B. Tanner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_J/0/1/0/all/0/1">J. Yang</a> Axions are a promising cold dark matter candidate. Haloscopes, which use the conversion of axions to photons in the presence of a magnetic field to detect axions, are the basis of microwave cavity searches such as the Axion Dark Matter eXperiment (ADMX). To search for lighter, low frequency axions in the sub $2times10^{-7}$ eV (50 MHz) range, a tunable lumped-element LC circuit has been proposed. For the first time, through ADMX SLICRead More →

Comments on the CKN Bound. (arXiv:1911.05778v1 [hep-th]) <a href="http://arxiv.org/find/hep-th/1/au:+Banks_T/0/1/0/all/0/1">Tom Banks</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Draper_P/0/1/0/all/0/1">Patrick Draper</a> Cohen, Kaplan, and Nelson (CKN) conjectured that the UV and IR cutoffs of effective quantum field theories coupled to gravity are not independent, but are connected by the physics of black holes. We interpret the CKN bound as a scale-dependent depletion of the QFT density of states and discuss various aspects of the bound on small and large scales. For laboratory experiments, we argue that the bound provides small corrections to ordinary quantum field theory, which we estimate to be of order $m_e/M_p$ for $g-2$ of the electron. On large scales, weRead More →

Evolving LMXBs: CARB Magnetic Braking. (arXiv:1911.05790v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Van_K/0/1/0/all/0/1">K. X. Van</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ivanova_N/0/1/0/all/0/1">N. Ivanova</a> The formation of low-mass X-ray binaries (LMXBs) is an ongoing challenge in stellar evolution. The important subset of LMXBs are the binary systems with a neutron star (NS) accretor. In NS LMXBs with non-degenerate donors, the mass transfer is mainly driven by magnetic braking. The discrepancies between the observed mass transfer (MT) rates and the theoretical models were known for a while. Theory predictions of the MT rates are too weak and differ by an order of magnitude or more. Recently, we showed that with the standard magnetic braking, it isRead More →

The Assembly of the First Massive Black Holes. (arXiv:1911.05791v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Inayoshi_K/0/1/0/all/0/1">Kohei Inayoshi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Visbal_E/0/1/0/all/0/1">Eli Visbal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Haiman_Z/0/1/0/all/0/1">Zolt&#xe1;n Haiman</a> The existence of $approx$10^9 Msun supermassive black holes (SMBHs) within the first billion year of the universe has stimulated numerous ideas for the prompt formation and rapid growth of BHs in the early universe. Here we review ways in which the seeds of massive BHs may have first assembled, how they may have subsequently grown as massive as $approx$10^9 Msun, and how multi-messenger observations could distinguish between different SMBH assembly scenarios. We conclude the following: (1) The ultra-rare $approx$10^9 Msun SMBHs represent only the tip ofRead More →

On the Expansion, Age, and Origin of the Puzzling Shell/Pulsar Wind Nebula G310.6-1.6. (arXiv:1911.05792v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Reynolds_S/0/1/0/all/0/1">Stephen P. Reynolds</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Borkowski_K/0/1/0/all/0/1">Kazimierz J. Borkowski</a> We present a 142-ks Chandra observation of the enigmatic combination supernova remnant G310.6-1.6 consisting of a bright pulsar-wind nebula driven by an energetic pulsar, surrounded by a highly circular, very faint shell with a featureless, probably synchrotron, spectrum. Comparison with an observation 6 years earlier shows no measurable expansion of the shell, though some features in the pulsar-wind nebula have moved. We find an expansion age of at least 2500 yr, implying a current shock velocity less than about 1000 km/s. WeRead More →

Extended FLRW Models: dynamical cancellation of cosmological anisotropies. (arXiv:1911.05793v1 [gr-qc]) <a href="http://arxiv.org/find/gr-qc/1/au:+Thorsrud_M/0/1/0/all/0/1">Mikjel Thorsrud</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Normann_B/0/1/0/all/0/1">Ben D. Normann</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Pereira_T/0/1/0/all/0/1">Thiago S. Pereira</a> We investigate a corner of the Bianchi models that has not received much attention: “extended FLRW models” (eFLRW) defined as a cosmological model with underlying anisotropic Bianchi geometry that nevertheless expands isotropically and can be mapped onto a reference FLRW model with the same expansion history. In order to investigate the stability and naturalness of such models in a dynamical systems context, we consider spatially homogeneous models that contain a massless scalar field $varphi$ and a non-tilted perfect fluid obeying an equation of stateRead More →

Response to NITRD, NCO, NSF Request for Information on “Update to the 2016 National Artificial Intelligence Research and Development Strategic Plan”. (arXiv:1911.05796v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Amundson_J/0/1/0/all/0/1">J. Amundson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Annis_J/0/1/0/all/0/1">J. Annis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Avestruz_C/0/1/0/all/0/1">C. Avestruz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bowring_D/0/1/0/all/0/1">D. Bowring</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Caldeira_J/0/1/0/all/0/1">J. Caldeira</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cerati_G/0/1/0/all/0/1">G. Cerati</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chang_C/0/1/0/all/0/1">C. Chang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dodelson_S/0/1/0/all/0/1">S. Dodelson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Elvira_D/0/1/0/all/0/1">D. Elvira</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Farahi_A/0/1/0/all/0/1">A. Farahi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Genser_K/0/1/0/all/0/1">K. Genser</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gray_L/0/1/0/all/0/1">L. Gray</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gutsche_O/0/1/0/all/0/1">O. Gutsche</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Harris_P/0/1/0/all/0/1">P. Harris</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kinney_J/0/1/0/all/0/1">J. Kinney</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kowalkowski_J/0/1/0/all/0/1">J. B. Kowalkowski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kutschke_R/0/1/0/all/0/1">R. Kutschke</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mrenna_S/0/1/0/all/0/1">S. Mrenna</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nord_B/0/1/0/all/0/1">B. Nord</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Para_A/0/1/0/all/0/1">A. Para</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pedro_K/0/1/0/all/0/1">K. Pedro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Perdue_G/0/1/0/all/0/1">G. N. Perdue</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Scheinker_A/0/1/0/all/0/1">A. Scheinker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Spentzouris_P/0/1/0/all/0/1">P. Spentzouris</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+John_J/0/1/0/all/0/1">J. St. John</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tran_N/0/1/0/all/0/1">N. Tran</a>, <aRead More →

A Dissection of Spatially Resolved AGN Feedback across the Electromagnetic Spectrum. (arXiv:1911.05805v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Fischer_T/0/1/0/all/0/1">Travis Fischer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Smith_K/0/1/0/all/0/1">Krista Lynne Smith</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kraemer_S/0/1/0/all/0/1">Steve Kraemer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schmitt_H/0/1/0/all/0/1">Henrique Schmitt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Crenshaw_D/0/1/0/all/0/1">D. Michael Crenshaw</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Koss_M/0/1/0/all/0/1">Michael Koss</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mushotzky_R/0/1/0/all/0/1">Richard Mushotzky</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Larson_K/0/1/0/all/0/1">Kirsten Larson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+U_V/0/1/0/all/0/1">Vivian U</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rigby_J/0/1/0/all/0/1">Jane Rigby</a> We present optical SuperNova Integral Field Spectrograph (SNIFS) integral field spectroscopy, Hubble Space Telescope optical imaging, Chandra X-ray imaging, and Very Large Array radio interferometry of the merging galaxy 2MASX J04234080+0408017, which hosts a Seyfert 2 active galactic nucleus (AGN) at z = 0.046. Our observations reveal that radiatively driven, ionized gas outflows are successful to distances > 10 kpcRead More →

NuSTAR Uncovers an Extremely Local Compton-thick AGN in NGC 4968. (arXiv:1911.05813v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+LaMassa_S/0/1/0/all/0/1">Stephanie M. LaMassa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yaqoob_T/0/1/0/all/0/1">Tahir Yaqoob</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Boorman_P/0/1/0/all/0/1">Peter G. Boorman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tzanavaris_P/0/1/0/all/0/1">Panayiotis Tzanavaris</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Levenson_N/0/1/0/all/0/1">N. A. Levenson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gandhi_P/0/1/0/all/0/1">Poshak Gandhi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ptak_A/0/1/0/all/0/1">Andrew F. Ptak</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Heckman_T/0/1/0/all/0/1">Timothy M. Heckman</a> We present the analysis of Chandra and NuSTAR spectra of NGC 4968, a local (D$sim$44 Mpc) 12$mu$m-selected Seyfert 2 galaxy, enshrouded within Compton-thick layers of obscuring gas. We find no evidence of variability between the Chandra and NuSTAR observations (separated by 2 years), and between the two NuSTAR observations (separated by 10 months). Using self-consistent X-ray models, we rule out the scenario where theRead More →