Volume 2 Issue 3, March 2018

Volume 2 Issue 3

A window to the Martian past

Phyllosilicates (clays) on Mars, such as the light—toned outcrops at Mawrth Vallis shown on the cover, could form during warm and wet intermittent periods in a generally cold early Mars. This model solves the contradiction on the state of ancient Mars between mineralogical and geomorphological observations and the most accepted climate theories.

See Bishop et al. and News & Views by Bridges

Image: Christoph Gross, Freie Universität Berlin. Cover Design: Bethany Vukomanovic.

Editorial

  • Editorial |

    Galaxies hosting actively accreting supermassive black holes make up roughly 10% of all galaxies in the Universe. Nevertheless, due to their immense energy output, active galactic nuclei are widely regarded as regulators of their host galaxy growth. But does observational evidence stack up?

Comment & Opinion

  • Comment |

    Observations and simulations show that outflows in active galactic nuclei contain gas in different phases. To understand their true impact on galaxy evolution, we advocate consistent and unbiased investigation of these multiphase winds in large active galactic nuclei samples.

    • Claudia Cicone
    • , Marcella Brusa
    • , Cristina Ramos Almeida
    • , Giovanni Cresci
    • , Bernd Husemann
    •  & Vincenzo Mainieri
  • Comment |

    Galaxy-scale outflows powered by actively accreting supermassive black holes are routinely detected, and they have been associated with both the suppression and triggering of star formation. Recent observational evidence and simulations are favouring a delayed mechanism that connects outflows and star formation.

    • Giovanni Cresci
    •  & Roberto Maiolino

Books & Arts

Research Highlights

News & Views

  • News & Views |

    A peak in the infrared phase curve occurring after eclipse suggests a westward shift in the dayside hotspot of hot giant exoplanet CoRoT-2b, calling into question our understanding of atmospheric dynamics on hot gas giants.

    • Joanna K. Barstow
  • News & Views |

    A new geochemical study shows that short-lived warm and wet episodes during a globally cold early Mars could have formed the clay deposits detected on the Martian surface. This model can reconcile climate models with mineralogical and geomorphological evidence.

    • John C. Bridges
  • News & Views |

    One of the astrophysical sources that gives rise to the mysterious transients known as fast radio bursts is embedded in a highly magnetized environment, such as the vicinity of an accreting massive black hole or the birth nebula of a highly magnetized neutron star.

    • Brian D. Metzger
  • Meeting Report |

    Feedback from active galactic nuclei (AGNs) remains controversial despite its wide acceptance as necessary to regulate massive galaxy growth. Consequently, we held a workshop in October 2017, at Leiden’s Lorentz Center, to distinguish between the reality and myths of feedback.

    • Bernd Husemann
    •  & Chris M. Harrison

Reviews

Research

  • Letter |

    A geochemical model for the state of early Mars suggests that short-term warm events grafted onto a generally cold climate could form Al-rich phyllosilicates in short-lived surface water bodies and Mg-rich ones in hydrothermal subsurface environments.

    • Janice L. Bishop
    • , Alberto G. Fairén
    • , Joseph R. Michalski
    • , Luis Gago-Duport
    • , Leslie L. Baker
    • , Michael A. Velbel
    • , Christoph Gross
    •  & Elizabeth B. Rampe
  • Letter |

    Hubble observations of the TRAPPIST-1 system exclude the presence of H2-dominated cloud-free atmospheres for the three planets within or around the system’s habitable zone. This result supports the hypothesis that these planets are terrestrial in nature.

    • Julien de Wit
    • , Hannah R. Wakeford
    • , Nikole K. Lewis
    • , Laetitia Delrez
    • , Michaël Gillon
    • , Frank Selsis
    • , Jérémy Leconte
    • , Brice-Olivier Demory
    • , Emeline Bolmont
    • , Vincent Bourrier
    • , Adam J. Burgasser
    • , Simon Grimm
    • , Emmanuël Jehin
    • , Susan M. Lederer
    • , James E. Owen
    • , Vlada Stamenković
    •  & Amaury H. M. J. Triaud
  • Letter |

    Global circulation theory predicts strong equatorial jets at the equators of hot gas giant exoplanets that blow hot gas to the east, resulting in an eastward hotspot. Here, Dang et al. present a detection of a hotspot significantly offset to the west.

    • Lisa Dang
    • , Nicolas B. Cowan
    • , Joel C. Schwartz
    • , Emily Rauscher
    • , Michael Zhang
    • , Heather A. Knutson
    • , Michael Line
    • , Ian Dobbs-Dixon
    • , Drake Deming
    • , Sudarsan Sundararajan
    • , Jonathan J. Fortney
    •  & Ming Zhao
  • Letter |

    The distribution of circularity of stellar orbits within 300 galaxies of the present-day Universe, with masses between 108.7 and 1011.9 M , is directly observed by the CALIFA survey and provides a benchmark for galaxy simulations.

    • Ling Zhu
    • , Glenn van de Ven
    • , Remco van den Bosch
    • , Hans-Walter Rix
    • , Mariya Lyubenova
    • , Jesús Falcón-Barroso
    • , Marie Martig
    • , Shude Mao
    • , Dandan Xu
    • , Yunpeng Jin
    • , Aura Obreja
    • , Robert J. J. Grand
    • , Aaron A. Dutton
    • , Andrea V. Macciò
    • , Facundo A. Gómez
    • , Jakob C. Walcher
    • , Rubén García-Benito
    • , Stefano Zibetti
    •  & Sebastian F. Sánchez
  • Letter |

    A sample of quiescent early-type galaxies (ETGs) — home to most of the stars in the local Universe — at z ~ 1.8 contain two orders of magnitude more dust at a fixed stellar mass than local ETGs. This implies a higher gas content, at odds with the idea that star formation at this redshift is quenched by gas removal.

    • R. Gobat
    • , E. Daddi
    • , G. Magdis
    • , F. Bournaud
    • , M. Sargent
    • , M. Martig
    • , S. Jin
    • , A. Finoguenov
    • , M. Béthermin
    • , H. S. Hwang
    • , A. Renzini
    • , G. W. Wilson
    • , I. Aretxaga
    • , M. Yun
    • , V. Strazzullo
    •  & F. Valentino
  • Article |

    A model for the non-thermal emission of pulsars can fit their γ- and X-ray spectra using just four physical parameters. The model explains several spectral features, and can be used to predict the detectability of pulsars in X-rays given the γ-ray emission, and vice versa.

    • Diego F. Torres

Amendments & Corrections