Blogs about galaxies, singles ones on in clusters

Arp 107 (Image ESA/Hubble & NASA, J. Dalcanton)

An image captured by the Hubble Space Telescope shows Arp 107, a pair of interacting galaxies heading towards a collision. The two galaxies, the spiral galaxy UGC 5984 (or PGC 32620) and the elliptical galaxy MCG +05-26-025 (or PGC 32628), will finish this process in a merger. UGC 5984 is a Seyfert galaxy, a class characterized by an active galactic nucleus that doesn’t block the view of the rest of the galaxy and spectral lines that show a strong ionization. The pair represents an interesting case of the early phase of a galaxy merger.

A diagram illustrating the combined power of the James Webb and Hubble space telescopes in studying Cepheids present in the galaxy NGC 5584 with the NIRCam (Near-Infrared Camera) and WFC3 (Wide Field Camera 3) instruments, respectively

An article accepted for publication in “The Astrophysical Journal” reports the results of calculating the universe’s expansion rate based on the observation of Cepheids with the James Webb Space Telescope. In particular, a team of researchers led by Adam Riess used the NIRCam instrument to observe over 330 cepheids in the galaxies NGC 4258 and NGC 5584. The results are more precise than those obtained in the past with the Hubble Space Telescope but confirm the accuracy of the previous calculation of the universe’s expansion rate. This leaves open the question of the difference in results obtained with different methods.

International Gemini Observatory/NOIRLab/NSF/AURA/P. Marenfeld QuasarPōniuāena

An article published in “The Astrophysical Journal Letters” reports the discovery of the most distant cold molecular gas in the interstellar medium of the galaxy that hosts the quasar nicknamed Pōniuāʻena, one of the three most distant bright quasars known. A team of researchers led by some associates of the Italian National Institute of Astrophysics (INAF) used observations conducted with the NOEMA (Northern Extended Millimeter Array) radio telescope to obtain the detection of the gas, to be precise carbon monoxide. This study can provide valuable information to understand how a supermassive black hole could have a mass 1.5 billion times the Sun’s when the universe was “only” 700 million years old.

On the left, the galaxy cluster WHL0137-08 and in the inset, the galaxy nicknamed the Sunrise Arc in its distorted form, which hosts the star Earendel

Two articles, one published in “The Astrophysical Journal” and one in “The Astrophysical Journal Letters”, report various aspects of a study of Earendel, the most distant single known star. Two teams of researchers with several members in common used observations conducted with the James Webb Space Telescope to obtain new details of this star, which even such a powerful instrument could only detect thanks to a gravitational lens. Officially cataloged as WHL0137-LS, the new study turns out to be a class B blue giant, much more massive than the Sun. Webb’s observations also reveal a luminous component that could belong to a less massive companion and not even the Hubble Space Telescope was able to detect.

Early commissioning test image – VIS instrument full field of view and zoom in for detail

ESA has published the first test images captured by the Euclid Space Telescope. As soon as Euclid reached its destination, testing of both instruments, VIS and NISP, began and will continue for a couple of months to calibrate them until they reach optimal performance. They are necessary tasks to enable Euclid to conduct the scientific mission which consists of investigating the dark universe to try to solve some cosmological mysteries such as that of the acceleration of the universe expansion.