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4 results on '"Department of Physics and Astronomy [Flagstaff]"'

1. The bow shock and kinematics of PSR J1959+2048

Author

Roger W. Romani, Adam Deller, Lucas Guillemot, Hao Ding, Martijn de Vries, Chase Parker, Robert T. Zavala, Aurélien Chalumeau, Ismaël Cognard, Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), Stanford University, Swinburne University of Technology [Melbourne], Unité Scientifique de la Station de Nançay (USN), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Wuhan University of Technology (WHUT), Vrije Universiteit Amsterdam [Amsterdam] (VU), Department of Physics and Astronomy [Flagstaff], Northern Arizona University [Flagstaff], AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Astrophysics::Galaxy Astrophysics, Pulsar wind nebulae
Abstract

Pulsar Hα bow shocks provide rare opportunities to constrain the energetics and kinematics of the relativistic pulsar wind. We have acquired optical imaging and integral field unit spectroscopy of the bow shock of the millisecond pulsar PSR J1959+2048, measuring the shock symmetry axis at a position angle = 213.2 ± 0.°2 and showing that this slow nonradiative shock has a broad-to-narrow line component ratio I b /I n = 4. The data show that the pulsar’s velocity lies 2.°2 out of the plane of the sky. Coupled with a new fit for its timing proper motion, giving μ tot = 30.05 mas yr−1 and a Very Long Baseline Array (VLBA) interferometric parallax measurement giving d = 2.57 − 0.77 + 1.84 kpc (90% range), we have unusually complete information on the pulsar kinematics. The bow shock constraints on the wind momentum flux imply that, at the best-fit parallax distance, the pulsar moment of inertia must be very large and/or the Hα efficiency at its modest shock velocity must be very high.

Published
2022

2. The Geology and Geophysics of Kuiper Belt Object (486958) Arrokoth

Author

Harold A. Weaver, J. Wm. Parker, Paolo Tanga, Stuart J. Robbins, Harold J. Reitsema, Carver J. Bierson, Dennis C. Reuter, Matthew E. Hill, Dale P. Cruikshank, Stephen Gwyn, Mark R. Showalter, Alex Parker, B. H. May, William M. Grundy, Oliver L. White, Douglas P. Hamilton, Orkan M. Umurhan, M. Mountain, Jj Kavelaars, Kelsi N. Singer, Alan D. Howard, David E. Trilling, E. Bernardoni, Ross A. Beyer, Ralph L. McNutt, D. Borncamp, John Stansberry, Simon B. Porter, Chloe B. Beddingfield, L. H. Wasserman, Bonnie J. Buratti, J. T. Keane, C. Fuentes, Ivan Linscott, Anne J. Verbiscer, Jean-Marc Petit, D. E. Jennings, A. L. Chaikin, Paul M. Schenk, Leslie A. Young, M. R. Piquette, Marc W. Buie, Catherine B. Olkin, Carly Howett, Mihaly Horanyi, Tod R. Lauer, Veronica J. Bray, Richard P. Binzel, Carey M. Lisse, Jeffrey M. Moore, Scott S. Sheppard, Silvia Protopapa, J. R. Spencer, William B. McKinnon, A. Y. Abedin, Kirby Runyon, G. R. Gladstone, S. A. Stern, Tetsuharu Fuse, Susan D. Benecchi, Rajani D. Dhingra, I. N. Reid, Mohamed Ramy El-Maarry, Martin Pätzold, H. A. Elliott, Amanda M. Zangari, Jason D. Hofgartner, H. Karoji, T. Stryk, Henry B. Throop, M. J. Kinczyk, Matthew J. Holman, David E. Kaufmann, A. F. Cheng, Daniel T. Britt, David J. McComas, David J. Tholen, Southwest Research Institute [Boulder] (SwRI), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Massachusetts Institute of Technology (MIT), Southwest Research Institute [San Antonio] (SwRI), Lowell Observatory [Flagstaff], Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], NASA Goddard Space Flight Center (GSFC), NRC Herzberg Institute of Astrophysics, National Research Council of Canada (NRC), Princeton University, Rhenish Institute for Environmental Research (RIU), University of Cologne, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy [Flagstaff], and Northern Arizona University [Flagstaff]

Subjects
Solar System, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Contact binary, 01 natural sciences, Impact crater, Neptune, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Multidisciplinary, Spacecraft, business.industry, Geophysics, Radius, Accretion (astrophysics), es, 13. Climate action, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Formation and evolution of the Solar System, business, Geology, Astrophysics - Earth and Planetary Astrophysics
Abstract

Examining Arrokoth The New Horizons spacecraft flew past the Kuiper Belt object (486958) Arrokoth (also known as 2014 MU 69 ) in January 2019. Because of the great distance to the outer Solar System and limited bandwidth, it will take until late 2020 to downlink all the spacecraft's observations back to Earth. Three papers in this issue analyze recently downlinked data, including the highest-resolution images taken during the encounter (see the Perspective by Jewitt). Spencer et al. examined Arrokoth's geology and geophysics using stereo imaging, dated the surface using impact craters, and produced a geomorphological map. Grundy et al. investigated the composition of the surface using color imaging and spectroscopic data and assessed Arrokoth's thermal emission using microwave radiometry. McKinnon et al. used simulations to determine how Arrokoth formed: Two gravitationally bound objects gently spiraled together during the formation of the Solar System. Together, these papers determine the age, composition, and formation process of the most pristine object yet visited by a spacecraft. Science , this issue p. eaay3999 , p. eaay3705 , p. eaay6620 ; see also p. 980

Published
2020

3. Aerosol nucleation over oceans and the role of galactic cosmic rays

Author

J. Kazil, E. R. Lovejoy, M. C. Barth, K. O’Brien, EGU, Publication, Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado [Boulder]-National Oceanic and Atmospheric Administration (NOAA), ESRL Chemical Sciences Division [Boulder] (CSD), NOAA Earth System Research Laboratory (ESRL), National Oceanic and Atmospheric Administration (NOAA)-National Oceanic and Atmospheric Administration (NOAA), MMM/ACD, National Center for Atmospheric Research [Boulder] (NCAR), Department of Physics and Astronomy [Flagstaff], and Northern Arizona University [Flagstaff]

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, respiratory system, complex mixtures, Physics::Atmospheric and Oceanic Physics
Abstract

We investigate formation of sulfate aerosol in the marine troposphere from neutral and charged nucleation of H2SO4 and H2O. A box model of neutral and charged aerosol processes is run on a grid covering the oceans. Input data are taken from a model of galactic cosmic rays in the atmosphere, and from global chemistry and transport models. We find a weak aerosol production over the tropical oceans in the lower and middle troposphere, and a stronger production at higher latitudes, most notably downwind of industrial regions. The highest aerosol production, however, occurs in the upper troposphere, in particular in the tropics. This finding supports the proposition by which non-sea salt marine boundary layer aerosol in tropical regions does not form in situ, but nucleates in the upper troposphere from convectively lifted and cloud processed boundary layer air rich in aerosol precursor gases, from where it descends in subsiding air masses compensating convection. Convection of boundary layer air also appears to drive the formation of condensation nuclei in the tropical upper troposphere which maintains the stratospheric aerosol layer in the absence of volcanic activity. Neutral nucleation contributes only marginally to aerosol production in our simulations. This highlights the importance of charged binary and of ternary nucleation involving ammonia for aerosol formation. In clean marine regions however, ammonia concentrations seem too low to support ternary nucleation, making binary nucleation from ions a likely pathway for sulfate aerosol formation. On the other hand, our analysis indicates that the variation of ionization by galactic cosmic rays over the decadal solar cycle does not entail a response in aerosol production and cloud cover via the second indirect aerosol effect that would explain observed variations in global cloud cover. We estimate that the variation in radiative forcing resulting from a response of clouds to the change in galactic cosmic ray ionization and subsequent aerosol production over the decadal solar cycle is smaller than the concurrent variation of total solar irradiance.

Published
2006

4. Analysis of peptides synthesized in the presence of SAz-1 montmorillonite and Cu(2+) exchanged hectorite.

Author

Porter TL, Eastman MP, Bain E, and Begay S

Subjects
Chromatography, High Pressure Liquid, Glycine chemistry, Peptides chemical synthesis, Spectrometry, Mass, Electrospray Ionization, Tyrosine chemistry, Bentonite chemistry, Copper chemistry, Peptides analysis, Silicates chemistry
Abstract

We have investigated the synthesis of oligopeptides containing glycine and tyrosine in the presence of the clay minerals montmorillonite (non-exchanged, SAz-1) and Cu(2+) exchanged hectorite. In both cases, homopolymers of the two amino acids are formed, as are mixed peptides. In the case of Cu(2+) hectorite, mixed oligopeptides up to trimers are detected in small amounts. For montmorillonite, heterogeneous oligopeptides up to hexamers are detected. Our experiments indicate montmorillonite is more effective in promoting oligopeptide formation than Cu(2+) hectorite. Analysis of the oligopeptide sequences formed on the montmorillonite surfaces indicates preferential synthesis of certain Gly-Tyr sequences over others.

Published
2001
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