Blog about cosmology

Some ASKAP antennas with the Milky Way overhead (Image courtesy Alex Cherney/CSIRO. All rights reserved)

An article published in the journal “Nature” reports the results of a survey on Fast Radio Bursts (FRBs), intense radio emissions from other galaxies. A team of researchers used the Australia Square Kilometer Array Pathfinder (ASKAP) radio telescope to search for Fast Radio Bursts discovering 20 in a year, almost doubling the number previously detected. Their analysis suggests that their characteristics evolve over time.

A possible pulsar formed after a long-duration supernova

An article published in the “Astrophysical Journal Letters” describes a study on the supernova Sn 2012au. Sometimes supernovae remain bright for a long time if the remnants of the explosion collide with hydrogen layers, but Dan Milisavljevic of Purdue University wondered if this could happen without any interaction of that kind. His team studied Sn 2012au concluding that after the supernova a neutron star of the pulsar type was formed with a rotation and a magnetic field sufficient to create a cloud of gas around it, called in jargon a pulsar wind nebula.

A relativistic jet after the kilonova

An article published in the journal “Nature” describes the observations of a relativistic jet that followed the merger between two neutron stars discovered in August 2017, the first case of an event detected and studied in both electromagnetic and gravitational waves. A team of researchers used the precise measurements made with some radio telescopes to establish that a narrow jet of particles was emitted at a speed close to that of light after the event.

HDUV GOODS-North Field Compass (Image NASA, ESA, P. Oesch (University of Geneva), and M. Montes (University of New South Wales))

An article published in the journal “Astrophysical Journal Supplement Series” presents the Hubble Deep UV (HDUV) Legacy Survey program, a great panorama of the universe’s evolutionary history based on observations carried out with the Hubble Space Telescope. A team of researchers exploited Hubble’s ultraviolet detection capabilities, combining it with infrared and visible light observations, also from other telescopes, to extend previous surveys with a field of view that includes about 15,000 galaxies, including 12,000 in which there’s star formation.

GRB 161219B and its echo

An article published in the journal “Astrophysical Journal” describes the study of a sort of echo generated by a gamma-ray burst cataloged as GRB 161219B emitted by a newborn black hole. The gamma-ray emissions lasted only seven seconds but emissions at other electromagnetic frequencies lasted even for weeks, which enabled a team of astronomers to use the ALMA radio telescope to study the ones at millimeter wavelengths. They offered other information on the gamma-ray burst and on the characteristics of its powerful jets.