Connect with us

Science

A bright millisecond-duration radio burst from a Galactic magnetar – Nature.com

Published

 on


  • 1.

    Kaspi, V. M. & Beloborodov, A. M. Magnetars. Annu. Rev. Astron. Astrophys. 55, 261–301 (2017).

    ADS 
    CAS 

    Google Scholar
     

  • 2.

    Olausen, S. A. & Kaspi, V. M. The McGill Magnetar Catalog. Astrophys. J. Suppl. Ser. 212, 6 (2014).

    ADS 

    Google Scholar
     

  • 3.

    Esposito, P. et al. A very young radio-loud magnetar. Astrophys. J. Lett. 896, 30 (2020).

    ADS 

    Google Scholar
     

  • 4.

    Petroff, E., Hessels, J. W. T. & Lorimer, D. R. Fast radio bursts. Astron. Astrophys. Rev. 27, 4 (2019).

    ADS 

    Google Scholar
     

  • 5.

    Spitler, L. G. et al. A repeating fast radio burst. Nature 531, 202–205 (2016).

    ADS 
    CAS 

    Google Scholar
     

  • 6.

    The CHIME/FRB Collaboration. CHIME/FRB detection of eight new repeating fast radio burst sources. Astrophys. J. Lett. 885, 24 (2019).

    ADS 

    Google Scholar
     

  • 7.

    Kumar, P. et al. Faint repetitions from a bright fast radio burst source. Astrophys. J. Lett. 887, 30 (2019).

    ADS 

    Google Scholar
     

  • 8.

    Fonseca, E. et al. Nine new repeating fast radio burst sources from CHIME/FRB. Astrophys. J. Lett. 891, 6 (2020).

    ADS 

    Google Scholar
     

  • 9.

    Lyubarsky, Y. A model for fast extragalactic radio bursts. Mon. Not. R. Astron. Soc. 442, L9–L13 (2014).

    ADS 

    Google Scholar
     

  • 10.

    Beloborodov, A. M. A flaring magnetar in FRB 121102? Astrophys. J. Lett. 843, 26 (2017).

    ADS 

    Google Scholar
     

  • 11.

    Metzger, B. D., Margalit, B. & Sironi, L. Fast radio bursts as synchrotron maser emission from decelerating relativistic blast waves. Mon. Not. R. Astron. Soc. 485, 4091–4106 (2019).

    ADS 
    CAS 

    Google Scholar
     

  • 12.

    CHIME/FRB Collaboration et al. The CHIME Fast Radio Burst Project: system overview. Astrophys. J. 863, 48 (2018).

    ADS 

    Google Scholar
     

  • 13.

    Palmer, D. M. A forest of bursts from SGR 1935+2154. Astron. Telegr. 13675 (2020).

  • 14.

    Israel, G. L. et al. The discovery, monitoring and environment of SGR J1935+2154. Mon. Not. R. Astron. Soc. 457, 3448–3456 (2016).

    ADS 
    CAS 

    Google Scholar
     

  • 15.

    Cordes, J. M. & Lazio, T. J. W. NE2001. I. A new model for the galactic distribution of free electrons and its fluctuations. Preprint at https://arxiv.org/abs/astro-ph/0207156 (2002).

  • 16.

    Yao, J. M., Manchester, R. N. & Wang, N. A new electron-density model for estimation of pulsar and FRB distances. Astrophys. J. 835, 29 (2017).

    ADS 

    Google Scholar
     

  • 17.

    He, C., Ng, C.-Y. & Kaspi, V. The correlation between dispersion measure and X-ray column density from radio pulsars. Astrophys. J. 768, 64 (2013).

    ADS 

    Google Scholar
     

  • 18.

    Kothes, R., Sun, X., Gaensler, B. & Reich, W. A radio continuum and polarization study of SNR G57.2+0.8 associated with magnetar SGR 1935+2154. Astrophys. J. 852, 54 (2018).

    ADS 

    Google Scholar
     

  • 19.

    Zhang, C. F. et al. A highly polarised radio burst detected from SGR 1935+2154 by FAST. Astron. Telegr. 13699 (2020).

  • 20.

    CHIME/FRB. A fast radio burst associated with a Galactic magnetar. Nature https://doi.org/10.1038/s41586-020-2872-x (2020).

  • 21.

    Zhou, P. et al. Revisiting the distance, environment and supernova properties of SNR G57.2+0.8 that hosts SGR 1935+2154. Preprint at https://arxiv.org/abs/2005.03517 (2020).

  • 22.

    Mereghetti, S. et al. INTEGRAL IBIS and SPI-ACS detection of a hard X-ray counterpart of the radio burst from SGR 1935+2154. Astron. Telegr. 13685 (2020).

  • 23.

    Ridnaia, A. et al. Konus-Wind observation of hard X-ray counterpart of the radio burst from SGR 1935+2154. Astron. Telegr. 13688 (2020).

  • 24.

    Zhang, S. N. et al. Insight-HXMT X-ray and hard X-ray detection of the double peaks of the fast radio burst from SGR 1935+2154. Astron. Telegr. 13696 (2020).

  • 25.

    Zhang, S. N. et al. Geocentric time correction for Insight-HXMT detection of the X-ray counterpart of the FRB by CHIME and STARE2 from SGR 1935+2154. Astron. Telegr. 13704 (2020).

  • 26.

    Tendulkar, S. P., Kaspi, V. M. & Patel, C. Radio nondetection of the SGR 1806–20 giant flare and implications for fast radio bursts. Astrophys. J. 827, 59 (2016).

    ADS 

    Google Scholar
     

  • 27.

    Scholz, P. et al. Simultaneous X-ray, gamma-ray, and radio observations of the repeating fast radio burst FRB 121102. Astrophys. J. 846, 80 (2017).

    ADS 

    Google Scholar
     

  • 28.

    von Kienlin, A. Fermi GBM GRBs 191104 A, B, C and triggers 594534420/191104185 and 594563923/191104527 are not GRBs. GCN Circ. 26163 (2019).

  • 29.

    Ambrosi, E., D’Elia, V., Kennea, J. A. & Palmer, D. Trigger 933276: Swift detection of further activity from SGR 1935+2154. GCN Circ. 26169 (2019).

  • 30.

    Palmer, D. Trigger 933285: Swift detection of the brightest burst so far from SGR 1935+2154. GCN Circ. 26171 (2019).

  • 31.

    Pearlman, A. B., Majid, W. A., Prince, T. A., Kocz, J. & Horiuchi, S. Pulse morphology of the Galactic Center magnetar PSR J1745–2900. Astrophys. J. 866, 160 (2018).

    ADS 

    Google Scholar
     

  • 32.

    Hessels, J. W. T. et al. FRB 121102 bursts show complex time–frequency structure. Astrophys. J. Lett. 876, 23 (2019).

    ADS 

    Google Scholar
     

  • 33.

    Burgay, M. et al. Search for FRB and FRB-like single pulses in Parkes magnetar data. In Pulsar Astrophysics: the Next Fifty Years (eds Weltevrede, P. et al.) 319–321 (2018).

  • 34.

    Bera, A. & Chengalur, J. N. Super-giant pulses from the Crab pulsar: energy distribution and occurrence rate. Mon. Not. R. Astron. Soc. 490, L12–L16 (2019).

    ADS 

    Google Scholar
     

  • 35.

    Marcote, B. et al. A repeating fast radio burst source localized to a nearby spiral galaxy. Nature 577, 190–194 (2020).

    ADS 
    CAS 

    Google Scholar
     

  • 36.

    The CHIME/FRB Collaboration. Periodic activity from a fast radio burst source. Nature 582, 351–355 (2020).

    ADS 

    Google Scholar
     

  • 37.

    Patel, C. et al. PALFA single-pulse pipeline: new pulsars, rotating radio transients, and a candidate fast radio burst. Astrophys. J. 869, 181 (2018).

    ADS 
    CAS 

    Google Scholar
     

  • 38.

    Pol, N., Lam, M. T., McLaughlin, M. A., Lazio, T. J. W. & Cordes, J. M. Estimates of fast radio burst dispersion measures from cosmological simulations. Astrophys. J. 886, 135 (2019).

    ADS 
    CAS 

    Google Scholar
     

  • 39.

    Shannon, R. M. et al. The dispersion–brightness relation for fast radio bursts from a wide-field survey. Nature 562, 386–390 (2018).

    ADS 
    CAS 

    Google Scholar
     

  • 40.

    Hurley, K. et al. An exceptionally bright flare from SGR 1806–20 and the origins of short-duration γ-ray bursts. Nature 434, 1098–1103 (2005).

    ADS 
    CAS 

    Google Scholar
     

  • 41.

    Lyutikov, M. Radio emission from magnetars. Astrophys. J. Lett. 580, 65–68 (2002).

    ADS 

    Google Scholar
     

  • 42.

    Kumar, P., Lu, W. & Bhattacharya, M. Fast radio burst source properties and curvature radiation model. Mon. Not. R. Astron. Soc. 468, 2726–2739 (2017).

    ADS 
    CAS 

    Google Scholar
     

  • 43.

    Zhang, Y. G. et al. Fast radio burst 121102 pulse detection and periodicity: a machine learning approach. Astrophys. J. 866, 149 (2018).

    ADS 

    Google Scholar
     

  • 44.

    Bhandari, S. et al. The Survey for Pulsars and Extragalactic Radio Bursts—II. New FRB discoveries and their follow-up. Mon. Not. R. Astron. Soc. 475, 1427–1446 (2018).

    ADS 
    CAS 

    Google Scholar
     

  • 45.

    Ravi, V. The prevalence of repeating fast radio bursts. Nat. Astron. 3, 928–391 (2019).

    ADS 

    Google Scholar
     

  • 46.

    Agarwal, D. et al. A fast radio burst in the direction of the Virgo cluster. Mon. Not. R. Astron. Soc. 490, 1–8 (2019).

    ADS 

    Google Scholar
     

  • 47.

    Taylor, M. et al. The core collapse supernova rate from the SDSS-II Supernova Survey. Astrophys. J. 792, 135 (2014).

    ADS 

    Google Scholar
     

  • 48.

    Gourdji, K. et al. A sample of low-energy bursts from FRB 121102. Astrophys. J. Lett. 877, 19 (2019).

    ADS 

    Google Scholar
     

  • 49.

    Gajjar, V. et al. Highest frequency detection of FRB 121102 at 4–8 GHz using the Breakthrough Listen digital backend at the Green Bank Telescope. Astrophys. J. 863, 2 (2018).

    ADS 

    Google Scholar
     

  • 50.

    Bannister, K. W. et al. A single fast radio burst localized to a massive galaxy at cosmological distance. Science 365, 565–570 (2019).

    ADS 
    CAS 

    Google Scholar
     

  • 51.

    Ng, C. et al. CHIME FRB: an application of FFT beamforming for a radio telescope. In Proc. XXXII General Assembly and Scientific Symp. Intl Union of Radio Science (URSI GASS) J33-2 (2017).

  • 52.

    Masui, K. W. et al. Algorithms for FFT beamforming radio interferometers. Astrophys. J. 879, 16 (2019).

    ADS 
    CAS 

    Google Scholar
     

  • 53.

    Foreman-Mackey, D., Hogg, D. W., Lang, D. & Goodman, J. emcee: the MCMC hammer. Publ. Astron. Soc. Pacif. 125, 306 (2013).

    ADS 

    Google Scholar
     

  • 54.

    Newburgh, L. B. et al. Calibrating CHIME: a new radio interferometer to probe dark energy. Proc. SPIE 9145, 91454V (2014).


    Google Scholar
     

  • 55.

    Berger, P. et al. Holographic beam mapping of the CHIME pathfinder array. In Ground-based and Airborne Telescopes VI (eds Hall, H. J., Gilmozzi, R. & Marshall, H. K.) 99060D (SPIE, 2016).

  • 56.

    Bandura, K. et al. Canadian Hydrogen Intensity Mapping Experiment (CHIME) pathfinder. In Ground-based and Airborne Telescopes V (eds Stepp, L. M., Gilmozzi, R. & Hall, H. J.) 914522 (SPIE, 2014).

  • 57.

    Bandura, K. et al. ICE: a scalable, low-cost FPGA-based telescope signal processing and networking system. J. Astron. Instrum. 5, 1641005 (2016).


    Google Scholar
     

  • 58.

    Burn, B. J. On the depolarization of discrete radio sources by Faraday dispersion. Mon. Not. R. Astron. Soc. 133, 67–83 (1966).

    ADS 

    Google Scholar
     

  • 59.

    Brentjens, M. A. & de Bruyn, A. G. Faraday rotation measure synthesis. Astron. Astrophys. 441, 1217–1228 (2005).

    ADS 

    Google Scholar
     

  • 60.

    Sobey, C. et al. Low-frequency Faraday rotation measures towards pulsars using LOFAR: probing the 3D Galactic halo magnetic field. Mon. Not. R. Astron. Soc. 484, 3646–3664 (2019).

    ADS 
    CAS 

    Google Scholar
     

  • 61.

    Ester, M., Kriegel, H.-P., Sander, J. & Xu, X. A density-based algorithm for discovering clusters in large spatial databases with noise. In Proc. Second Intl Conf. Knowledge Discovery and Data Mining, KDD’96 (eds Simoudis, E., Han, J. & Fayyad, U.) 226–231 (AAAI, 1996).

  • 62.

    Arnaud, K. A. Xspec: the first ten years. In Astronomical Data Analysis Software and Systems V (eds Jacoby, G. & Barnes, J.) 17 (ASP, 1996).

  • 63.

    Karachentsev, I. D. & Kaisina, E. I. Star formation properties in the local volume galaxies via Hα and far-ultraviolet fluxes. Astron. J. 146, 46 (2013).

    ADS 

    Google Scholar
     

  • 64.

    Jarrett, T. H. et al. The WISE Extended Source Catalog (WXSC). I. The 100 largest galaxies. Astrophys. J. Suppl. Ser. 245, 25 (2019).

    ADS 
    CAS 

    Google Scholar
     

  • 65.

    Gehrels, N. Confidence limits for small numbers of events in astrophysical data. Astrophys. J. 303, 336–346 (1986).

    ADS 
    CAS 

    Google Scholar
     

  • Let’s block ads! (Why?)



    Source link

    Continue Reading

    Science

    Calgary man captures photo of SpaceX Dragon docked at the International Space Station – Calgary Herald

    Published

     on


    Article content

    When Shafqat Zaman takes photos of the International Space Station (ISS) from Calgary, it may help that he’s about 1 kilometre closer than photographers shooting from sea level.

    However, the ISS is still about 399 kilometres away, and moving at a speed of about 7.66 kilometres per second relative to the ground. However you measure it, snapping a shot of the orbiting laboratory is an incredible feat.

    Zaman captured this shot on Wednesday evening. It features a clear view of the SpaceX Dragon capsule, which lifted off on Nov. 15 and docked with the station about 27 hours later. It’s the white cone-shaped object on the left side, near the middle.

    The SpaceX Dragon capsule is the bright white cone on the left of the ISS. Photo by Shafqat Zaman /Submitted

    This wasn’t his first snapshot of the most expensive object ever constructed. Zaman captured several images of the ISS showing different angles as it passed overhead in late September.

    A series of 3 images of the ISS taken as it passed over Calgary in September 2020. Photo by Shafqat Zaman /Submitted

    He also captured this stunning transit of the ISS in front of the sun.

    A series of shots of the ISS passing in front of the sun. Photo by Shafqat Zaman /Submitted

    Zaman said he uses an 8″ Meade SCT telescope with a Canon M5 camera.

    Zaman’s telescope. Photo by Shafqat Zaman

    Let’s block ads! (Why?)



    Source link

    Continue Reading

    Science

    Landmark wheat genome discovery could shore up global food security – New Food

    Published

     on


    Project leader, Curtis Pozniak, compares the findings to locating a missing piece of your favourite puzzle, and hopes this will transform the way wheat is grown globally.

    Scientists believe the genome sequencing will lead to higher wheat yields around the world.

    An international team led by the University of Saskatchewan (USask) has sequenced the genomes for 15 wheat varieties representing breeding programmes around the world.

    This landmark discovery will enable scientists and breeders to identify influential genes for improved yield, pest resistance and other important crop traits much more quickly.

    The research results, published in Nature, provide what the research team has called the most comprehensive atlas of wheat genome sequences ever reported. The 10+ Genome Project collaboration involved more than 95 scientists from universities and institutes across Canada, Switzerland, Germany, Japan, the UK, Saudi Arabia, Mexico, Israel, Australia and the US.

    “It’s like finding the missing pieces for your favourite puzzle that you have been working on for decades,” said project leader Curtis Pozniak, wheat breeder and director of the USask Crop Development Centre (CDC). “By having many complete gene assemblies available, we can now help solve the huge puzzle that is the massive wheat pan-genome and usher in a new era for wheat discovery and breeding.”

    Scientific groups across the global wheat community are expected to use the new resource to identify genes linked to in-demand traits, such as pest and diseases resistance, which will accelerate breeding efficiency.

    “This resource enables us to more precisely control breeding to increase the rate of wheat improvement for the benefit of farmers and consumers, and meet future food demands,” Pozniak added.

    As one of the world’s most cultivated cereal crops, wheat plays an important role in global food security, providing about 20 percent of human caloric intake globally. The university says it’s estimated that wheat production must increase by more than 50 percent by 2050 to meet an increasing global demand – knowing which wheat genomes ‘best perform’ could be crucial in delivering this target.

    The researchers explain that they were able to track the unique DNA signatures of genetic material incorporated into modern cultivars from several of wheat’s undomesticated relatives by breeders over the last century.1

    “These wheat relatives have been used by breeders to improve disease resistance and stress resistance of wheat,” said Pozniak. “One of these relatives contributed a DNA segment to modern wheat that contains disease-resistant genes and provides protection against a number of fungal diseases. Our collaborators from Kansas State University and the International Maize and Wheat Improvement Center (CIMMYT) in Mexico, showed that this segment can improve yields by as much as 10 percent. Since breeding is a continual improvement process, we can continue to cross plants to select for this valuable trait.”

    Pozniak’s team, in collaboration with scientists from Agriculture and Agri-Food Canada, and National Research Council of Canada, also used the genome sequences to isolate an insect-resistant gene (Sm1). This gene enables wheat plants to withstand the orange wheat blossom midge, a pest which can cause more than $60 million in annual losses to Western Canadian producers.1

    “Understanding a causal gene like this is a game-changer for breeding because you can select for pest resistance more efficiently by using a simple DNA test than by manual field testing,” Pozniak concluded.

    References 

    1. www.nature.com/articles/s41586-020-2961-x 

    Let’s block ads! (Why?)



    Source link

    Continue Reading

    Science

    T. rex got huge via major teenage growth spurt – CBC.ca

    Published

     on


    Large meat-eating dinosaurs attained their great size through very different growth strategies, with some taking a slow and steady path and others experiencing an adolescent growth spurt, according to scientists who analyzed slices of fossilized bones.

    The researchers examined the annual growth rings — akin to those in tree trunks — in bones from 11 species of theropods, a broad group spanning all the big carnivorous dinosaurs including Tyrannosaurus rex and even birds. The study provides insight into the lives of some of the most fearsome predators ever to walk the Earth.

    The team looked at samples from museums in the United States, Canada, China and Argentina and even received clearance to cut into bones from one of the world’s most famous T. rex fossils, known as Sue and housed at the Field Museum in Chicago, using a diamond-tipped saw and drill.

    Sue’s leg bones — a huge femur and fibula — helped illustrate that T. rex and its relatives — known as tyrannosaurs — experienced a period of extreme growth during adolescence and reached full adult size by around age 20. Sue, measuring about 13 metres, lived around 33 years.

    Sue inhabited South Dakota about a million years before dinosaurs and many other species were wiped out by an asteroid impact 66 million years ago.

    Other groups of large theropods tended to have more steady rates of growth over a longer period of time. That growth strategy was detected in lineages that arose worldwide earlier in the dinosaur era and later were concentrated in the southern continents.

    Examples included Allosaurus and Acrocanthosaurus from North America, Cryolophosaurus from Antarctica and a recently discovered as-yet-unnamed species from Argentina that rivaled T. rex in size. The Argentine dinosaur, from a group called carcharodontosaurs, did not reach its full adult size until its 40s and lived to about age 50.

    Big theropods share the same general body design, walking on two legs and boasting large skulls, strong jaws and menacing teeth.

    “Prior to our study, it was known that T. rex grew very quickly, but it was not clear if all theropod dinosaurs reached gigantic size in the same way, or if there were multiple ways it was done,” said paleontologist and study lead author Tom Cullen of the North Carolina Museum of Natural Sciences and North Carolina State University, also affiliated with the Field Museum.

    The research was published this week in the journal Proceedings of the Royal Society B.

    “Theropod dinosaurs represent the largest bipedal animals to have ever lived and were also the dominant predators in terrestrial ecosystems for over 150 million years — more than twice as long as mammals have been dominant,” added University of Minnesota paleontologist and study co-author Peter Makovicky

    Let’s block ads! (Why?)



    Source link

    Continue Reading

    Trending