ALBERT

Description: Searches for transient astrophysical sources often reveal unexpected classes of objects that are useful physical laboratories. In a recent survey for pulsars and fast transients, we have uncovered four millisecond-duration radio transients all more than 40 degrees from the Galactic plane. The bursts' properties indicate that they are of celestial rather than terrestrial origin. Host galaxy and intergalactic medium models suggest that they have cosmological redshifts of 0.5 to 1 and distances of up to 3 gigaparsecs. No temporally coincident x- or gamma-ray signature was identified in association with the bursts. Characterization of the source population and identification of host galaxies offers an opportunity to determine the baryonic content of the universe.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Thornton, D -- Stappers, B -- Bailes, M -- Barsdell, B -- Bates, S -- Bhat, N D R -- Burgay, M -- Burke-Spolaor, S -- Champion, D J -- Coster, P -- D'Amico, N -- Jameson, A -- Johnston, S -- Keith, M -- Kramer, M -- Levin, L -- Milia, S -- Ng, C -- Possenti, A -- van Straten, W -- New York, N.Y. -- Science. 2013 Jul 5;341(6141):53-6. doi: 10.1126/science.1236789.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester, UK. thornton@jb.man.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23828936" target="_blank"〉PubMed〈/a〉

Description: Millisecond pulsars are thought to be neutron stars that have been spun-up by accretion of matter from a binary companion. Although most are in binary systems, some 30% are solitary, and their origin is therefore mysterious. PSR J1719-1438, a 5.7-millisecond pulsar, was detected in a recent survey with the Parkes 64-meter radio telescope. We show that this pulsar is in a binary system with an orbital period of 2.2 hours. The mass of its companion is near that of Jupiter, but its minimum density of 23 grams per cubic centimeter suggests that it may be an ultralow-mass carbon white dwarf. This system may thus have once been an ultracompact low-mass x-ray binary, where the companion narrowly avoided complete destruction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bailes, M -- Bates, S D -- Bhalerao, V -- Bhat, N D R -- Burgay, M -- Burke-Spolaor, S -- D'Amico, N -- Johnston, S -- Keith, M J -- Kramer, M -- Kulkarni, S R -- Levin, L -- Lyne, A G -- Milia, S -- Possenti, A -- Spitler, L -- Stappers, B -- van Straten, W -- New York, N.Y. -- Science. 2011 Sep 23;333(6050):1717-20. doi: 10.1126/science.1208890. Epub 2011 Aug 25.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Centre for Astrophysics and Supercomputing and ARC Centre for All-Sky Astrophysics (CAASTRO), Swinburne University of Technology, Post Office Box 218 Hawthorn, VIC 3122, Australia. mbailes@swin.edu.au〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21868629" target="_blank"〉PubMed〈/a〉

Description: The formation and growth processes of supermassive black holes (SMBHs) are not well constrained. SMBH population models, however, provide specific predictions for the properties of the gravitational-wave background (GWB) from binary SMBHs in merging galaxies throughout the universe. Using observations from the Parkes Pulsar Timing Array, we constrain the fractional GWB energy density (Omega(GW)) with 95% confidence to be Omega(GW)(H0/73 kilometers per second per megaparsec)(2) 〈 1.3 x 10(-9) (where H0 is the Hubble constant) at a frequency of 2.8 nanohertz, which is approximately a factor of 6 more stringent than previous limits. We compare our limit to models of the SMBH population and find inconsistencies at confidence levels between 46 and 91%. For example, the standard galaxy formation model implemented in the Millennium Simulation Project is inconsistent with our limit with 50% probability.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shannon, R M -- Ravi, V -- Coles, W A -- Hobbs, G -- Keith, M J -- Manchester, R N -- Wyithe, J S B -- Bailes, M -- Bhat, N D R -- Burke-Spolaor, S -- Khoo, J -- Levin, Y -- Oslowski, S -- Sarkissian, J M -- van Straten, W -- Verbiest, J P W -- Wang, J-B -- New York, N.Y. -- Science. 2013 Oct 18;342(6156):334-7. doi: 10.1126/science.1238012.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Commonwealth Scientific and Industrial Research Organisation (CSIRO) Astronomy and Space Science, Australia Telescope National Facility, Post Office Box 76, Epping, New South Wales 1710, Australia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24136962" target="_blank"〉PubMed〈/a〉

Description: Gravitational waves are expected to be radiated by supermassive black hole binaries formed during galaxy mergers. A stochastic superposition of gravitational waves from all such binary systems would modulate the arrival times of pulses from radio pulsars. Using observations of millisecond pulsars obtained with the Parkes radio telescope, we constrained the characteristic amplitude of this background, A(c,yr), to be 〈1.0 x 10(-15) with 95% confidence. This limit excludes predicted ranges for A(c,yr) from current models with 91 to 99.7% probability. We conclude that binary evolution is either stalled or dramatically accelerated by galactic-center environments and that higher-cadence and shorter-wavelength observations would be more sensitive to gravitational waves.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shannon, R M -- Ravi, V -- Lentati, L T -- Lasky, P D -- Hobbs, G -- Kerr, M -- Manchester, R N -- Coles, W A -- Levin, Y -- Bailes, M -- Bhat, N D R -- Burke-Spolaor, S -- Dai, S -- Keith, M J -- Oslowski, S -- Reardon, D J -- van Straten, W -- Toomey, L -- Wang, J-B -- Wen, L -- Wyithe, J S B -- Zhu, X-J -- New York, N.Y. -- Science. 2015 Sep 25;349(6255):1522-5. doi: 10.1126/science.aab1910.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Commonwealth Science and Industrial Research Organization (CSIRO) Astronomy and Space Science, Australia Telescope National Facility, Post Office Box 76, Epping, New South Wales 1710, Australia. International Centre for Radio Astronomy Research, Curtin University, Bentley, Western Australia 6102, Australia. ; Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Post Office Box 218, Hawthorn, Victoria 3122, Australia. ; Astrophysics Group, Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, UK. ; Monash Centre for Astrophysics, School of Physics and Astronomy, Monash University, Post Office Box 27, Victoria 3800, Australia. ; Commonwealth Science and Industrial Research Organization (CSIRO) Astronomy and Space Science, Australia Telescope National Facility, Post Office Box 76, Epping, New South Wales 1710, Australia. ; Department of Electrical and Computer Engineering, University of California-San Diego, La Jolla, CA 92093, USA. ; International Centre for Radio Astronomy Research, Curtin University, Bentley, Western Australia 6102, Australia. ; National Radio Astronomical Observatory, Array Operations Center, Post Office Box O, Socorro, NM 87801-0387, USA. ; Commonwealth Science and Industrial Research Organization (CSIRO) Astronomy and Space Science, Australia Telescope National Facility, Post Office Box 76, Epping, New South Wales 1710, Australia. Department of Astronomy, School of Physics, Peking University, Beijing 100871, China. ; Jodrell Bank Centre for Astrophysics, University of Manchester, Manchester M13 9PL, UK. ; Department of Physics, Universitat Bielefeld, Universitatsstrasse 25, D-33615 Bielefeld, Germany. Max-Planck-Institut fur Radioastronomie, Auf dem Hugel 69, 53121 Bonn, Germany. ; Xinjiang Astronomical Observatory, Chinese Academy of Sciences, 150 Science 1-Street, Urumqi, Xinjiang 830011, China. ; School of Physics, University of Western Australia, Crawley, Western Australia 6009, Australia. ; School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26404832" target="_blank"〉PubMed〈/a〉

Description: Li et al. (Reports, 18 April 2014, p. 292) proposed a unity nitrous acid (HONO) yield for reaction between nitrogen dioxide and the hydroperoxyl-water complex and suggested a substantial overestimation in HONO photolysis contribution to hydroxyl radical budget. Based on airborne observations of all parameters in this chemical system, we have determined an upper-limit HONO yield of 0.03 for the reaction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ye, Chunxiang -- Zhou, Xianliang -- Pu, Dennis -- Stutz, Jochen -- Festa, James -- Spolaor, Max -- Cantrell, Christopher -- Mauldin, Roy L -- Weinheimer, Andrew -- Haggerty, Julie -- New York, N.Y. -- Science. 2015 Jun 19;348(6241):1326. doi: 10.1126/science.aaa1992.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Wadsworth Center, New York State Department of Health, Albany, NY, USA. ; Wadsworth Center, New York State Department of Health, Albany, NY, USA. Department of Environmental Health Sciences, State University of New York, Albany, NY, USA. xianliang.zhou@health.ny.gov. ; Department of Environmental Health Sciences, State University of New York, Albany, NY, USA. ; University of California, Los Angeles, CA, USA. ; University of Colorado, Boulder, CO, USA. ; University of Colorado, Boulder, CO, USA. Department of Physics, University of Helsinki, Helsinki, Finland. ; National Center for Atmosphere Research, Earth System Laboratory, Boulder, CO, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26089507" target="_blank"〉PubMed〈/a〉