Letters

  • Letter |

    The primordial abundance of helium, set minutes after the Big Bang, is typically measured in star-forming regions in local metal-poor galaxies. Here the helium abundance of an intergalactic gas cloud is calculated using the light of a background quasar instead.

    • Ryan J. Cooke
    •  & Michele Fumagalli
  • Letter |

    A giant protocluster of galaxies at redshift z ≈ 5.7 is found within a large overdense region containing at least 41 spectroscopically confirmed Lyα-emitting galaxies. It will collapse into one of the most massive clusters known to date.

    • Linhua Jiang
    • , Jin Wu
    • , Fuyan Bian
    • , Yi-Kuan Chiang
    • , Luis C. Ho
    • , Yue Shen
    • , Zhen-Ya Zheng
    • , John I. Bailey III
    • , Guillermo A. Blanc
    • , Jeffrey D. Crane
    • , Xiaohui Fan
    • , Mario Mateo
    • , Edward W. Olszewski
    • , Grecco A. Oyarzún
    • , Ran Wang
    •  & Xue-Bing Wu
  • Letter |

    The IRIS spectrograph observed upward ‘pseudo-shocks’ (shocks exhibiting a discontinuity only in plasma density) over an active region of the Sun. Modelling shows that such pseudo-shocks contribute significantly to coronal heating and mass transport.

    • Abhishek Kumar Srivastava
    • , Krzysztof Murawski
    • , Blażej Kuźma
    • , Dariusz Patryk Wójcik
    • , Teimuraz V. Zaqarashvili
    • , Marco Stangalini
    • , Zdzislaw E. Musielak
    • , John Gerard Doyle
    • , Pradeep Kayshap
    •  & Bhola N. Dwivedi
  • Letter |

    Predictions for the clustering of galaxies based on general relativity (GR) and on one of its more compelling variants are contrasted with observations. The former agree impressively well with the data, providing strong confirmation of GR on cosmological scales.

    • Jian-hua He
    • , Luigi Guzzo
    • , Baojiu Li
    •  & Carlton M. Baugh
  • Letter |

    The identification and dating of ~30 cryovolcanic domes on Ceres from Dawn data shows that cryovolcanism has been continuous on the dwarf planet at least for the last 2.5 Gyr, but not at rates comparable with standard volcanism on terrestrial planets.

    • Michael M. Sori
    • , Hanna G. Sizemore
    • , Shane Byrne
    • , Ali M. Bramson
    • , Michael T. Bland
    • , Nathaniel T. Stein
    •  & Christopher T. Russell
  • Letter |

    Probing the pre-explosion environments of hydrogen-poor superluminous supernovae is important for understanding how they exploded. Here, Lunnan et al. infer the presence of a fast-moving circumstellar shell around iPTF16eh through the detection of a resonance-line light echo, which indicates the massive progenitor experienced pulsational pair instability shell ejections.

    • R. Lunnan
    • , C. Fransson
    • , P. M. Vreeswijk
    • , S. E. Woosley
    • , G. Leloudas
    • , D. A. Perley
    • , R. M. Quimby
    • , Lin Yan
    • , N. Blagorodnova
    • , B. D. Bue
    • , S. B. Cenko
    • , A. De Cia
    • , D. O. Cook
    • , C. U. Fremling
    • , P. Gatkine
    • , A. Gal-Yam
    • , M. M. Kasliwal
    • , S. R. Kulkarni
    • , F. J. Masci
    • , P. E. Nugent
    • , A. Nyholm
    • , A. Rubin
    • , N. Suzuki
    •  & P. Wozniak
  • Letter |

    The mechanisms that sustain turbulence in a molecular cloud are not well understood. Using magnetohydrodynamic simulations, the effects of stellar winds on a cloud are studied, finding that energy can be efficiently transferred in magnetic waves generated by this stellar ‘feedback’.

    • Stella S. R. Offner
    •  & Yue Liu
  • Letter |

    The Patroclus–Menoetius Jupiter Trojan binary could survive its travel from the Kuiper belt to Jupiter’s orbit only if the giant planets’ migrations happened within ~100 Myr after the birth of the Solar System and not after ~700 Myr, as suggested instead by the Late Heavy Bombardment.

    • David Nesvorný
    • , David Vokrouhlický
    • , William F. Bottke
    •  & Harold F. Levison
  • Letter |

    Cosmochemical evidence is used to constrain models of Jupiter formation, which unfolds in three distinct phases: a rapid pebble accretion during the first Myr, followed by a slower growth controlled by larger planetesimals, ending in a runaway gas accretion stage.

    • Yann Alibert
    • , Julia Venturini
    • , Ravit Helled
    • , Sareh Ataiee
    • , Remo Burn
    • , Luc Senecal
    • , Willy Benz
    • , Lucio Mayer
    • , Christoph Mordasini
    • , Sascha P. Quanz
    •  & Maria Schönbächler
  • Letter |

    A data-driven study of the too-big-to-fail problem of Milky Way dwarf spheroidals within the self-interacting dark matter paradigm finds a good description of their stellar kinematics and compatibility with the concentration–mass relation of pure cold dark matter simulations.

    • Mauro Valli
    •  & Hai-Bo Yu
  • Letter |

    Star TYC 429-2097-1 contains the most lithium of any giant star, but lithium is too fragile to survive in the deep layers of a stellar atmosphere. How does the enrichment arise? Yan et al. rule out external sources (engulfment, accretion), favouring an internal process called ‘extra mixing’.

    • Hong-Liang Yan
    • , Jian-Rong Shi
    • , Yu-Tao Zhou
    • , Yong-Shou Chen
    • , Er-Tao Li
    • , Suyalatu Zhang
    • , Shao-Lan Bi
    • , Ya-Qian Wu
    • , Zhi-Hong Li
    • , Bing Guo
    • , Wei-Ping Liu
    • , Qi Gao
    • , Jun-Bo Zhang
    • , Ze-Ming Zhou
    • , Hai-Ning Li
    •  & Gang Zhao
  • Letter |

    Double-shell planetary nebula HuBi 1 has an inner shell that emits in low ionization potential species, and an outer shell that emits in high-ionization species. This is the inverse of the usual case. The cause is the nebula’s rapidly fading central star that went through a ‘born-again’ event.

    • Martín A. Guerrero
    • , Xuan Fang
    • , Marcelo M. Miller Bertolami
    • , Gerardo Ramos-Larios
    • , Helge Todt
    • , Alexandre Alarie
    • , Laurence Sabin
    • , Luis F. Miranda
    • , Christophe Morisset
    • , Carolina Kehrig
    •  & Saúl A. Zavala
  • Letter |

    Thirty years after an initial, tentative detection, the molecule 26AlF has now been firmly detected in space, by the observation of four different rotational transitions towards stellar merger remnant CK Vul. Curiously, CK Vul and similar objects are unlikely to be major sources of Galactic 26Al.

    • Tomasz Kamiński
    • , Romuald Tylenda
    • , Karl M. Menten
    • , Amanda Karakas
    • , Jan Martin Winters
    • , Alexander A. Breier
    • , Ka Tat Wong
    • , Thomas F. Giesen
    •  & Nimesh A. Patel
  • Letter |

    A dark, ribbon-like structure at Jupiter’s magnetic equator marks a depletion of ionospheric H3+ caused by a lack of photoelectrons. These photoelectrons, which collide with molecular hydrogen to form H3+, are deviated away by magnetic field lines.

    • Tom S. Stallard
    • , Angeline G. Burrell
    • , Henrik Melin
    • , Leigh N. Fletcher
    • , Steve Miller
    • , Luke Moore
    • , James O’Donoghue
    • , John E. P. Connerney
    • , Takehiko Satoh
    •  & Rosie E. Johnson
  • Letter |

    The X-ray-induced photodesorption of water from astrophysical ices, intact, has been little studied. However, it could be a key process in producing the cold water vapour that is seen in these regions. Here, the yield of such a mechanism is experimentally quantified.

    • R. Dupuy
    • , M. Bertin
    • , G. Féraud
    • , M. Hassenfratz
    • , X. Michaut
    • , T. Putaud
    • , L. Philippe
    • , P. Jeseck
    • , M. Angelucci
    • , R. Cimino
    • , V. Baglin
    • , C. Romanzin
    •  & J.-H. Fillion
  • Letter |

    The strong gravitational lensing signal around the massive cluster PSZ2 G099.86+58.45 indicates environment matter density in notable excess of the cosmological mean and implies that enhancing mechanisms around high-mass halos can be very effective.

    • Mauro Sereno
    • , Carlo Giocoli
    • , Luca Izzo
    • , Federico Marulli
    • , Alfonso Veropalumbo
    • , Stefano Ettori
    • , Lauro Moscardini
    • , Giovanni Covone
    • , Antonio Ferragamo
    • , Rafael Barrena
    •  & Alina Streblyanska
  • Letter |

    Late-time optical and near-infrared observations of the binary neutron star merger GW170817 are at odds with kilonova models but match a Gaussian-structured relativistic jet, which would have launched a high-luminosity short gamma-ray burst to an aligned observer.

    • J. D. Lyman
    • , G. P. Lamb
    • , A. J. Levan
    • , I. Mandel
    • , N. R. Tanvir
    • , S. Kobayashi
    • , B. Gompertz
    • , J. Hjorth
    • , A. S. Fruchter
    • , T. Kangas
    • , D. Steeghs
    • , I. A. Steele
    • , Z. Cano
    • , C. Copperwheat
    • , P. A. Evans
    • , J. P. U. Fynbo
    • , C. Gall
    • , M. Im
    • , L. Izzo
    • , P. Jakobsson
    • , B. Milvang-Jensen
    • , P. O’Brien
    • , J. P. Osborne
    • , E. Palazzi
    • , D. A. Perley
    • , E. Pian
    • , S. Rosswog
    • , A. Rowlinson
    • , S. Schulze
    • , E. R. Stanway
    • , P. Sutton
    • , C. C. Thöne
    • , A. de Ugarte Postigo
    • , D. J. Watson
    • , K. Wiersema
    •  & R. A. M. J. Wijers
  • Letter |

    All inner main-belt asteroids, and not just those belonging to a specific family as previously thought, originate from the splintering of a few large asteroids. The history of such precursors determines the compositional variety we observe in asteroids and meteorites.

    • Stanley F. Dermott
    • , Apostolos A. Christou
    • , Dan Li
    • , Thomas. J. J. Kehoe
    •  & J. Malcolm Robinson
  • Letter |

    Massive binary star Eta Carinae drives the strongest colliding wind shock in the solar neighbourhood. Using NuSTAR and XMM-Newton data, Eta Car has now been convincingly shown to accelerate non-thermal particles, contributing to the Galactic cosmic ray flux.

    • Kenji Hamaguchi
    • , Michael F. Corcoran
    • , Julian M. Pittard
    • , Neetika Sharma
    • , Hiromitsu Takahashi
    • , Christopher M. P. Russell
    • , Brian W. Grefenstette
    • , Daniel R. Wik
    • , Theodore R. Gull
    • , Noel D. Richardson
    • , Thomas I. Madura
    •  & Anthony F. J. Moffat
  • Letter |

    A method of atmospheric retrieval for exoplanets that uses supervised ‘random forest’ machine learning, less time-consuming than standard techniques, is presented. Tests on Hubble spectra of WASP-12b give results consistent with standard atmospheric retrievals.

    • Pablo Márquez-Neila
    • , Chloe Fisher
    • , Raphael Sznitman
    •  & Kevin Heng
  • Letter |

    The X-ray polarization properties of the black hole binary Cygnus X-1 in its hard state, combined with spectral and timing data, reveals that the accretion disk corona is either an extended structure or located far from the black hole.

    • M. Chauvin
    • , H.-G. Florén
    • , M. Friis
    • , M. Jackson
    • , T. Kamae
    • , J. Kataoka
    • , T. Kawano
    • , M. Kiss
    • , V. Mikhalev
    • , T. Mizuno
    • , N. Ohashi
    • , T. Stana
    • , H. Tajima
    • , H. Takahashi
    • , N. Uchida
    •  & M. Pearce
  • Letter |

    Evidence for the earliest phase of planet formation, dust grain growth, has been seen in the very young and massive circumstellar disk around low-mass protostar TMC1A. Such systems, still rich in gas, are responsible for the high-mass end of the exoplanet mass distribution.

    • Daniel Harsono
    • , Per Bjerkeli
    • , Matthijs H. D. van der Wiel
    • , Jon P. Ramsey
    • , Luke T. Maud
    • , Lars E. Kristensen
    •  & Jes K. Jørgensen
  • Letter |

    A bright X-ray outburst from a massive star cluster 12.5 kpc from a galactic centre fits the profile of a tidal disruption event (TDE), indicating the likely presence of an intermediate-mass black hole (IMBH). TDEs could be the most effective way of identifying IMBHs.

    • Dacheng Lin
    • , Jay Strader
    • , Eleazar R. Carrasco
    • , Dany Page
    • , Aaron J. Romanowsky
    • , Jeroen Homan
    • , Jimmy A. Irwin
    • , Ronald A. Remillard
    • , Olivier Godet
    • , Natalie A. Webb
    • , Holger Baumgardt
    • , Rudy Wijnands
    • , Didier Barret
    • , Pierre-Alain Duc
    • , Jean P. Brodie
    •  & Stephen D. J. Gwyn
  • Letter |

    By studying the properties of almost 200 disk galaxies, it is shown that modified Newtonian dynamics (MOND), or MOND-like alternative theories of gravity based on the existence of a fundamental acceleration scale, are ruled out as fundamental theories for galaxies at more than 10σ.

    • Davi C. Rodrigues
    • , Valerio Marra
    • , Antonino del Popolo
    •  & Zahra Davari
  • Letter |

    The presence of nanodiamonds in protoplanetary disks correlates strongly with the detection of anomalous microwave emission from the same disks, implying that spinning nanodiamonds rather than polycyclic aromatic hydrocarbons are the source of this puzzling ~30 GHz emission feature.

    • J. S. Greaves
    • , A. M. M. Scaife
    • , D. T. Frayer
    • , D. A. Green
    • , B. S. Mason
    •  & A. M. S. Smith
  • Letter |

    The Waves instrument on board the Juno spacecraft has detected ~1,600 lightning strokes in roughly 1 year of close approaches to Jupiter, indicated by low-dispersion rapid whistlers much shorter than those detected by Voyager 1 in Io’s plasma torus.

    • Ivana Kolmašová
    • , Masafumi Imai
    • , Ondřej Santolík
    • , William S. Kurth
    • , George B. Hospodarsky
    • , Donald A. Gurnett
    • , John E. P. Connerney
    •  & Scott J. Bolton
  • Letter |

    Cassini magnetic field and plasma observations find evidence of magnetic reconnection on the dayside of Saturn’s magnetosphere, which can explain local auroral pulsations and play a role in the transport of energetic particles within rapidly rotating magnetospheres.

    • R. L. Guo
    • , Z. H. Yao
    • , Y. Wei
    • , L. C. Ray
    • , I. J. Rae
    • , C. S. Arridge
    • , A. J. Coates
    • , P. A. Delamere
    • , N. Sergis
    • , P. Kollmann
    • , D. Grodent
    • , W. R. Dunn
    • , J. H. Waite
    • , J. L. Burch
    • , Z. Y. Pu
    • , B. Palmaerts
    •  & M. K. Dougherty
  • Letter |

    Images of 67P's nucleus from the Rosetta spacecraft, together with numerical simulations, show that the jet-like features of cometary comae can be produced by diffuse activity focused by the nucleus topography as well as non-uniform insolation over the surface.

    • X. Shi
    • , X. Hu
    • , S. Mottola
    • , H. Sierks
    • , H. U. Keller
    • , M. Rose
    • , C. Güttler
    • , M. Fulle
    • , S. Fornasier
    • , J. Agarwal
    • , M. Pajola
    • , C. Tubiana
    • , D. Bodewits
    • , C. Barbieri
    • , P. L. Lamy
    • , R. Rodrigo
    • , D. Koschny
    • , M. A. Barucci
    • , J.-L. Bertaux
    • , I. Bertini
    • , S. Boudreault
    • , G. Cremonese
    • , V. Da Deppo
    • , B. Davidsson
    • , S. Debei
    • , M. De Cecco
    • , J. Deller
    • , O. Groussin
    • , P. J. Gutiérrez
    • , S. F. Hviid
    • , W.-H. Ip
    • , L. Jorda
    • , J. Knollenberg
    • , G. Kovacs
    • , J.-R. Kramm
    • , E. Kührt
    • , M. Küppers
    • , L. M. Lara
    • , M. Lazzarin
    • , J. J. Lopez-Moreno
    • , F. Marzari
    • , G. Naletto
    • , N. Oklay
    • , I. Toth
    •  & J.-B. Vincent
  • Letter |

    The hypothesis of an ocean under the icy surface of Jupiter’s moon Europa is strengthened by in-situ evidence of a plume, inferred by Galileo’s magnetic field and plasma density measurements obtained during the spacecraft’s closest flyby to the moon.

    • Xianzhe Jia
    • , Margaret G. Kivelson
    • , Krishan K. Khurana
    •  & William S. Kurth
  • Letter |

    Supernova SN 2015bs is a hydrogen-rich type II supernova that appears to have been generated by a high-mass (>18 M) and low-metallicity (<0.1 Z) red supergiant progenitor.

    • J. P. Anderson
    • , L. Dessart
    • , C. P. Gutiérrez
    • , T. Krühler
    • , L. Galbany
    • , A. Jerkstrand
    • , S. J. Smartt
    • , C. Contreras
    • , N. Morrell
    • , M. M. Phillips
    • , M. D. Stritzinger
    • , E. Y. Hsiao
    • , S. González-Gaitán
    • , C. Agliozzo
    • , S. Castellón
    • , K. C. Chambers
    • , T. -W. Chen
    • , H. Flewelling
    • , C. Gonzalez
    • , G. Hosseinzadeh
    • , M. Huber
    • , M. Fraser
    • , C. Inserra
    • , E. Kankare
    • , S. Mattila
    • , E. Magnier
    • , K. Maguire
    • , T. B. Lowe
    • , J. Sollerman
    • , M. Sullivan
    • , D. R. Young
    •  & S. Valenti
  • Letter |

    Until recently, stellar evolution models had not been able to explain the presence of bright planetary nebulae in old stellar populations. Using the revised evolutionary tracks of Miller Bertolami (2016), it is now evident that lower-mass and longer-lived planetary nebulae can be bright.

    • K. Gesicki
    • , A. A. Zijlstra
    •  & M. M. Miller Bertolami
  • Letter |

    Analysis of a six-year time series of SDO/HMI images of the solar photosphere reveals the existence of global-scale equatorial Rossby waves in the Sun, which contain a large fraction of the radial vorticity at these scales.

    • Björn Löptien
    • , Laurent Gizon
    • , Aaron C. Birch
    • , Jesper Schou
    • , Bastian Proxauf
    • , Thomas L. Duvall Jr
    • , Richard S. Bogart
    •  & Ulrich R. Christensen
  • Letter |

    1I/‘Oumuamua observations from the Gemini North telescope, spanning approximately 8 hours on 27–28 October 2017, characterize the magnitude variations of the object and detect its tumbling nature, triggered by an old collision when it was still in its home system.

    • Michał Drahus
    • , Piotr Guzik
    • , Wacław Waniak
    • , Barbara Handzlik
    • , Sebastian Kurowski
    •  & Siyi Xu
  • Letter |

    In Galactic star-forming region W43-MM1 the core mass function (CMF), describing the mass distribution of the birthplaces of stars, is very different from the initial mass function (IMF), the mass distribution of newborn stars. Previously, the IMF was thought to reflect the CMF.

    • F. Motte
    • , T. Nony
    • , F. Louvet
    • , K. A. Marsh
    • , S. Bontemps
    • , A. P. Whitworth
    • , A. Men’shchikov
    • , Q. Nguyễn Lương
    • , T. Csengeri
    • , A. J. Maury
    • , A. Gusdorf
    • , E. Chapillon
    • , V. Könyves
    • , P. Schilke
    • , A. Duarte-Cabral
    • , P. Didelon
    •  & M. Gaudel
  • Letter |

    Α combined study of spatially resolved stellar kinematics and global stellar populations with the SAMI Galaxy Survey finds a strong correlation between the characteristic stellar population age of a galaxy and its intrinsic ellipticity.

    • Jesse van de Sande
    • , Nicholas Scott
    • , Joss Bland-Hawthorn
    • , Sarah Brough
    • , Julia J. Bryant
    • , Matthew Colless
    • , Luca Cortese
    • , Scott M. Croom
    • , Francesco d′Eugenio
    • , Caroline Foster
    • , Michael Goodwin
    • , Iraklis S. Konstantopoulos
    • , Jon S. Lawrence
    • , Richard M. McDermid
    • , Anne M. Medling
    • , Matt S. Owers
    • , Samuel N. Richards
    •  & Rob Sharp
  • Letter |

    The authors predict the ability of the Event Horizon Telescope (in its 2017 campaign) to distinguish between different theories of gravity based on images of Sagittarius A*; they suggest that it will not be possible.

    • Yosuke Mizuno
    • , Ziri Younsi
    • , Christian M. Fromm
    • , Oliver Porth
    • , Mariafelicia De Laurentis
    • , Hector Olivares
    • , Heino Falcke
    • , Michael Kramer
    •  & Luciano Rezzolla
  • Letter |

    Iron has been ramp compressed to the pressures it would experience in the core of a 3–4 Earth-mass terrestrial exoplanet, providing experimental constraints on the mass–radius relationship for a hypothetical pure iron planet.

    • Raymond F. Smith
    • , Dayne E. Fratanduono
    • , David G. Braun
    • , Thomas S. Duffy
    • , June K. Wicks
    • , Peter M. Celliers
    • , Suzanne J. Ali
    • , Amalia Fernandez-Pañella
    • , Richard G. Kraus
    • , Damian C. Swift
    • , Gilbert W. Collins
    •  & Jon H. Eggert
  • Letter |

    Cosmic filaments evolve nonlinearly from density fluctuations produced in the primordial Universe. Detection of cosmic microwave background lensing by filaments allows the measurement of how filaments trace the matter distribution on large scales.

    • Siyu He
    • , Shadab Alam
    • , Simone Ferraro
    • , Yen-Chi Chen
    •  & Shirley Ho
  • Letter |

    Aided by an optical ring-shaped structure visible in the recombination lines of neon and oxygen, a neutron star (the central compact object) has been identified in X-ray data of the supernova remnant 1E 0102.2–7219.

    • Frédéric P. A. Vogt
    • , Elizabeth S. Bartlett
    • , Ivo R. Seitenzahl
    • , Michael A. Dopita
    • , Parviz Ghavamian
    • , Ashley J. Ruiter
    •  & Jason P. Terry
  • Letter |

    Interferometric observations of 3C84 reveal a broad cylindrical jet a few hundred gravitational radii from the black hole, implying that the jet either undergoes a rapid lateral expansion on even smaller scales or is launched from the accretion disk.

    • G. Giovannini
    • , T. Savolainen
    • , M. Orienti
    • , M. Nakamura
    • , H. Nagai
    • , M. Kino
    • , M. Giroletti
    • , K. Hada
    • , G. Bruni
    • , Y. Y. Kovalev
    • , J. M. Anderson
    • , F. D’Ammando
    • , J. Hodgson
    • , M. Honma
    • , T. P. Krichbaum
    • , S.-S. Lee
    • , R. Lico
    • , M. M. Lisakov
    • , A. P. Lobanov
    • , L. Petrov
    • , B. W. Sohn
    • , K. V. Sokolovsky
    • , P. A. Voitsik
    • , J. A. Zensus
    •  & S. Tingay
  • Letter |

    The abundance of metals in Mercury’s interior is unique among the rocky planets of the Solar System. The characterization of the ‘super-Mercury’ exoplanet presented in this paper will improve our understanding of how Mercury-like planets can form and evolve.

    • A. Santerne
    • , B. Brugger
    • , D. J. Armstrong
    • , V. Adibekyan
    • , J. Lillo-Box
    • , H. Gosselin
    • , A. Aguichine
    • , J.-M. Almenara
    • , D. Barrado
    • , S. C. C. Barros
    • , D. Bayliss
    • , I. Boisse
    • , A. S. Bonomo
    • , F. Bouchy
    • , D. J. A. Brown
    • , M. Deleuil
    • , E. Delgado Mena
    • , O. Demangeon
    • , R. F. Díaz
    • , A. Doyle
    • , X. Dumusque
    • , F. Faedi
    • , J. P. Faria
    • , P. Figueira
    • , E. Foxell
    • , H. Giles
    • , G. Hébrard
    • , S. Hojjatpanah
    • , M. Hobson
    • , J. Jackman
    • , G. King
    • , J. Kirk
    • , K. W. F. Lam
    • , R. Ligi
    • , C. Lovis
    • , T. Louden
    • , J. McCormac
    • , O. Mousis
    • , J. J. Neal
    • , H. P. Osborn
    • , F. Pepe
    • , D. Pollacco
    • , N. C. Santos
    • , S. G. Sousa
    • , S. Udry
    •  & A. Vigan
  • Letter |

    A fast-evolving luminous transient (FELT) has been detected with a rise time to peak luminosity of only 2.2 days. This implies that the light-curve of this FELT cannot be powered by the decay of radioactive elements, as with type Ia supernovae.

    • A. Rest
    • , P. M. Garnavich
    • , D. Khatami
    • , D. Kasen
    • , B. E. Tucker
    • , E. J. Shaya
    • , R. P. Olling
    • , R. Mushotzky
    • , A. Zenteno
    • , S. Margheim
    • , G. Strampelli
    • , D. James
    • , R. C. Smith
    • , F. Förster
    •  & V. A. Villar
  • Letter |

    New hydrodynamical models are used to fit the Fermi-LAT data of the Galactic centre and show that the excess γ-ray emission of the region is better fitted by a non-spherical shape, indicating that it is not caused by dark-matter-related phenomena.

    • Oscar Macias
    • , Chris Gordon
    • , Roland M. Crocker
    • , Brendan Coleman
    • , Dylan Paterson
    • , Shunsaku Horiuchi
    •  & Martin Pohl