Cosmology

A HSC-SSP image of a galaxy cluster (Image NAOJ/HSC Project)

At the end of February the first data from the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) were released to the public. It’s a kind of cosmic census created using a large digital camera installed on the Subaru Telescope. The National Astronomical Observatory of Japan (NAOJ) developed a dedicated database and interface to use the wealth of data collected. One hope is to be closer to understand the fate of the universe.

Artistic concept of the galaxy A2744_YD4 (Image ESO/M. Kornmesser)

An article to be published in the journal “The Astrophysical Journal Letters” describes a research about the galaxy A2744_YD4, the most distant observed with the ALMA radio telescope. A team of astronomers led by Nicolas Laporte of University College London also used the X-shooter instrument on ESO’s VLT to confirm that we’re seeing A2744_YD4 as it was about six hundred million years after the Big Bang. The most interesting thing is the dust detection indicating that there were already several supernovae.

Protoplanetary disk with a dust trap seen as a bright ring (Image courtesy Jean-Francois Gonzalez)

An article published in the journal “Monthly Notices of the Royal Astronomical Society” describes a research that provides an explanation for one of the last remaining mysteries about planet formation. An international team of researchers conducted a series of simulations that show that in the protoplanetary disk around a young star dust traps form that accelerate the aggregation of pebble-sized fragments from which planets are born.

RX J1347.5-1145 galaxy cluster (Image ALMA (ESO/NAOJ/NRAO)/T. Kitayama (Toho University, Japan)/ESA/Hubble & NASA)

The ALMA radio telescope was used for the first time to measure the thermal Sunyaev-Zel’dovich Effect aiming it at the RX J1347.5-1145 galaxy cluster, located about 5 billion light years from Earth. This effect is due to the photons from the cosmic microwave background radiation that interact with high-energy electrons because of their temperature. Those measurements are useful to obtain information on the location and distribution of dense galactic clusters such as the one studied in this case.

The quasar HE0435-1223 seen through a gravitational lens that creates four images of it (Image ESA/Hubble, NASA, Suyu et al.)

A series of articles about to be published in the journal “Monthly Notices of the Royal Astronomical Society” describes various aspects of a new calculation of the Hubble constant, the value indicating the rate of expansion of the universe. A team of the H0LiCOW collaborative used the Hubble Space Telescope and other telescopes to measure the Hubble constant using the effect of gravitational lensing of 5 galaxies.