Cosmology

A NASA diagram of the PWS instrument's location and the antenna in common with the PRA instrument

An article published in the journal “Nature Astronomy” reports a study on the faint interstellar plasma waves detected by NASA’s Voyager 1 space probe. A team of researchers led by Stella Koch Ocker of Cornell University used a series of detections conducted by Voyager 1 while traveling a total distance that is about ten times the average distance of the Earth from the Sun which gives an idea of ​​the characteristics of the interstellar plasma when it’s not altered by events related to solar activity.

Artistic concept of the LOFAR radio telescope and fast radio burst FRB 20180916B (Image courtesy D. Futselaar / S.P. Tendulkar / ASTRON)

Two articles, one published in “The Astrophysical Journal Letters” and one published in “Nature Astronomy”, report various aspects of a research on the fast radio burst FRB 20180916B, whose emissions include the lowest frequencies at which such an event has been detected so far. Two teams of researchers with various members in common used detections obtained with the LOFAR radio telescope and the European VLBI network to study this fast radio burst that is repeating with a periodicity of just over 16 days. Its origin has been pinpointed in a small region around a neutron star.

The area around the supermassive black hole of the galaxy M87 in polarized light

Two articles published in “The Astrophysical Journal Letters” report different aspects of a study that led to the representation of the area around the supermassive black hole at the center of the galaxy M87 in polarized light. Scientists from the Event Horizon Telescope Collaboration used data collected in 2017 to obtain a new image that offers new information on the structure of the magnetic fields around the supermassive black hole. A third article published in the same journal reports the details of the observations conducted with the ALMA radio telescope during the 2017 observation campaign.

Different values of the Hubble constant

An article published in the journal “Astronomy & Astrophysics” reports a method to measure the expansion velocity of the universe that takes into account the differences between the type Ia supernovae used. A team of researchers led by Nandita Khetan, Ph.D. student at the Italian Gran Sasso Science Institute and associated with the Italian National Institute of Nuclear Physics, proposed a method to calibrate the distances of those supernovae using the surface brightness fluctuations (SBF) of their host galaxies. The result is closer to the ones already calculated with other methods than the one obtained without that calibration. It doesn’t solve the problem of very different values ​​of the so-called Hubble constant but suggests the possibility that the problem is due to instrumental inaccuracies and doesn’t require new physics.

Artist's concept of a gas filament disrupted by a star

An article published in the journal “Monthly Notices of the Royal Astronomical Society” reports the detection of a hydrogen filament about three trillion kilometers long in the cosmic neighborhood. A team of researchers led by Yuanming Wang, a doctoral candidate at the Australian University of Sydney, and Dr. Artem Tuntsov of Manly Astrophysics, used the ASKAP radio telescope to discover this ultra-low-temperature gas just 13 light-years from the Earth. In recent years, a lot of gas that forms the baryonic matter considered to be missing has been discovered in filaments that unite different galaxies, in this case it’s inside the Milky Way and in astronomical terms very close.