Cosmology, particle and astroparticle physics research in Norway

13/07/2022

The dawn of a new era in astronomy has begun as the world gets its first look at the full capabilities of NASA’s James Webb Space Telescope, a partnership with ESA (European Space Agency) and CSA (Canadian Space Agency).

13/06/2022

The most prominent mathematical cosmologist in Norway, Sigbjørn Hervik [1], was one of the winners of this year's Olav Thon Foundation prices [2], which he won for his teaching efforts in higher education.

According to one of his former phd students, the price is well earned:
- He was a great role model of science, always ready to explain the most difficult concepts in a simple, most penetrable manner, says Ben Normann, pausing before he continues.
- Despite of being a full professor with an outstanding international reputation he still takes the time to teach in highschool beside his professorship. That speaks volumes.

Sources
[1] Also; did you know that Hervik has his own fan page? You can find it here: https://www.facebook.com/awsomematteprofessor/. It is high time someone creates a wiki page for this eminent professor.
[2]: You may read more about the price here: https://olavthonstiftelsen.no/english/this-years-winners-of-the-olav-thon-foundation-2022/

Dette er en fan-side for Sigbjørn Hervik, professor ved UiS. Her kan fans kollektivt lovprise den f

12/01/2022

https://www.youtube.com/watch?v=1RXpHiCNsKU

https://scitechdaily.com/largest-3d-map-of-the-universe-ever-created-astrophysicists-fill-in-11-billion-years-of-our-universes-expansion-history/This video p...

30/12/2019

SOME HOLIDAY ENTERTAINMENT
What could possibly taste better than a crispy bit of cosmo-entertainment from Forskerstandup in these merry days of holiday? Lean back. And while we are at it: Happy new year!

www.uis.no

08/10/2019

NOBEL PRIZE IN PHYSICS 2019
This is a day of celebration for the field of cosmology and astrophysics, as this year's Nobel prize in physics was awarded to James Peebles (Princeton university) and Michel Mayor (University of Geneva) and Didier Queloz (University of Geneva and University of Cambridge).

Peebles, who is recognised with one half of the prize, is awarded "for theoretical discoveries in physical cosmology." Mayor and Queloz are awarded "for the discovery of an exoplanet orbiting a solar-type star."

You may read more here:

04/09/2019

PLANETARIUM CONFERENCE AT SANDNES
This weekend the Nordic Planetarium Association meets for a small conference at Vitenfabrikken in Sandnes. UiS Cosmology will also be present. Per A. Amundsen will present the "Planet Path," an outdoor excursion, and Ben David Normann will give a talk entitled "What the Cosmos?!"

Perhaps we will see you there?

14/08/2019

HAVE ASTRONOMERS DISPROVED THE BIG BANG?
Under this harassing title, Dr. Don. Lincoln from Fermilab helps us understand better the tension in recent measurements of the present expansion of the Universe. The video is therefore an excellent introduction to the matter we wrote about last month, the so-called "H0 tension". In the video Lincoln also lays out in a simple fashion what implications may be drawn thereof, should the tension call for new physics. Enjoy!

Link:

The theory of the Big Bang describes the biggest event of all time– the origin of the universe itself. Scientists are confident that this theory accurately d...

16/07/2019

MEASUREMENTS OF THE EXPANSION OF THE UNIVERSE DO NOT ALL AGREE

The current expansion rate (H0) of the Universe can be both measured locally and derived from the angle subtended by the sound horizon as observed in CMB temperature fluctuations. That is to say: Both the very early observational end (CMB) of the visible expansion history, and the very late, provide us with absolute distance ladders. These two ladders should of course agree.

The problem is that they don't.

This is an acknowledged problem in today's cosmology, and the discrepancy between the values derived through the different methods is dubbed "the H0 tension." It is an unsolved puzzle of today's cosmology, and who knows: It might be a hint of new physics!

In the link below you can read more about both the problem and the solutions investigated so far.

Link:

03/05/2019

WHY IS THE PICTURE OF A BLACK HOLE IMPORTANT?
If you are interested in astronomy or the like -- or even if you are not! -- you are likely to have heard about the recent picture capturing of a supermassive black hole. The short documentary linked to below [2] about the discovery might be of interest to anybody. The hole was predicted to be inside the galaxy Messier 87 in the Virgo cluster, and the picture of it was eventually captured by the Event Horizon Telescope (EHT), which is an international collaboration linking telescopes around the globe to read the night sky to unprecedented detail. We have been talking about black holes for so long now, that one may wonder why this image is so important.

The importance of the picture lies in the fact that we have never been so close to a direct obseration of a black hole. The Schwarzschild metric (which describes a certain type of black holes) was discovered already in 1915, and since then theoretical physicists have developed the idea and theory further and further -- never truly knowing whether such objects exist outside of theory. We have had ample reason to believe in their existence, however. First, general relativity as a theory has been put on trial numerous times, so far withstanding all attempts at falsification. According to the theory, black holes should exist. Second, we have observed black holes indirectly multiple times. One of the most famous such observations, however, is the rather recent 2016 LIGO detection of gravitational waves. The waves originated from the merger of two black holes. And this year, 100 years after general relativity was established as the correct theory of gravity, another piece of evidence was found: A picture of a black hole! Well... to be more precise it is a picture of the shadow of a black hole.

Sources:
[1] https://iopscience.iop.org/article/10.3847/2041-8213/ab0ec7/meta
[2] https://www.youtube.com/watch?v=omz77qrDjsU
https://www.youtube.com/watch?v=omz77qrDjsU

The Event Horizon Telescope (EHT) — a planet-scale array of eight ground-based radio telescopes forged through international collaboration — was designed to ...

10/04/2019

UIS COSMOLOGY IN FORSKNING.NO
This week we find one of UiS Cosmology's ph.D. researchers, Ben David Normann, and his supervisor Sigbjørn Hervik in a Forskning.no news article. The article is based on Normann's presentation at RCN's dissemination contest "Researchers Grand Prix." The news story from Forskning.no is based on a paper published a year ago [1]. If you are Norwegian, however, and not an expert, it might be more fun to have a look at Forskning.no's article. Also, you might want to have a look at Ben Normann' presentation in the Regional finals here in Stavanger:

https://www.youtube.com/watch?time_continue=3&v=NzcuVMCxBL4



Sources:
[1] https://iopscience.iop.org/article/10.1088/1361-6382/aab3a7

Observasjoner tyder på at universet utvider seg symmetrisk i alle retningene. Men hvorfor det er slik, er det foreløpig ingen forskere som har forklart fullt ut. Nå er splitter nye forklaringer lagt på bordet.

10/03/2019

GRAVITATIONAL LENSING AND NEURAL NETWORKS
Today the amount of data retrieved from the night sky is piling up. And if the analysis of the data is continuing with today's rate, we will just have to dung it up in piles of "unanalysed" for decades and centuries to come. Now; this would be so if it were not for fast automated analysis of the incomprehensible amount of data. The Dark Energy Survey alone has covered 300 million galaxies (!!) in the periode 2013-2018.

One very important probe on the universe, is Gravitational lensing (GL). Though not too many strong gravitational lensing events has been observed yet, the number is expected to increase by a factor of hundred thousand in this age of precision cosmology. In order to cope with this enormous amount of data, machine learning is currently being integrated into the standard analysis. This Nature paper, for instance [1], uses convolutional neural networks to facilitate the task of quantifying the amount of distortion caused by a lense. It reportedly speeds up the process by a factor of ten millions, and that with comparable accuracy!

Understanding the distortion, means understanding the mass distribution of the lens. Understanding the mass distribution of the lens , means pinning down the dark matter distribution in the lense!

Sources:
[1]

Estimates of parameters of strong gravitational lenses are obtained in an automated way using convolutional neural networks, with similar accuracy and greatly improved speed compared to previous methods.