Archive for Weak Lensing

Weekly Update at the Open Journal of Astrophysics – 08/03/2025

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , , , , , , , , on March 8, 2025 by telescoper

Time for the weekly Saturday morning update of papers published at the Open Journal of Astrophysics. Since the last update we have published four new papers, which brings the number in Volume 8 (2025) up to 25 and the total so far published by OJAp up to 260.

In chronological order of publication, the four papers published this week, with their overlays, are as follows. You can click on the images of the overlays to make them larger should you wish to do so.

The first paper to report is “Partition function approach to non-Gaussian likelihoods: information theory and state variables for Bayesian inference” by Rebecca Maria Kuntz, Heinrich von Campe, Tobias Röspel, Maximilian Philipp Herzog, and Björn Malte Schäfer, all from the University of Heidelberg (Germany). It was published on Wednesday March 5th 2025 in the folder Cosmology and NonGalactic Astrophysics and it discusses the relationship between information theory and thermodynamics with applications to Bayesian inference in the context of cosmological data sets.

 

You can read the officially accepted version of this paper on arXiv here.

The second paper of the week  is “The Cosmological Population of Gamma-Ray Bursts from the Disks of Active Galactic Nuclei” by Hoyoung D. Kang & Rosalba Perna (Stony Brook), Davide Lazzati (Oregon State), and Yi-Han Wang (U. Nevada), all based in the USA. It was published on Thursday 6th March 2025 in the folder High-Energy Astrophysical Phenomena. The authors use models for GRB electromagnetic emission to simulate the cosmological occurrence and observational detectability of both long and short GRBs within AGN disks

You can find the officially accepted version of this paper on arXiv here.

The next two papers were published on Friday 7th March 2025.

“The distribution of misalignment angles in multipolar planetary nebulae” by Ido Avitan and Noam Soker (Technion, Haifa, Israel) analyzes the statistics of measured misalignment angles in multipolar planetary nebulae implies a random three-dimensional angle distribution limited to <60 degrees. It is in the folder Solar and Stellar Astrophysics.

Here is the overlay:

 

The official published version can be found on the arXiv here.

The last paper to report this week is “The DESI-Lensing Mock Challenge: large-scale cosmological analysis of 3×2-pt statistics” by Chris Blake (Swinburne, Australia) and 43 others; this is a large international collaboration and I apologize for not being able to list all the authors here!

This one is in the folder marked Cosmology and NonGalactic Astrophysics; it presents an end-to-end simulation study designed to test the analysis pipeline for the Dark Energy Spectroscopic Instrument (DESI) Year 1 galaxy redshift dataset combined with weak gravitational lensing from other surveys.

The overlay is here:

 

You can find the “final” version on arXiv here.

That’s all for this week. It’s good to see such an interesting variety of topics. I’ll do another update next Saturday

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Three New Publications at the Open Journal of Astrophysics

Posted in OJAp Papers, The Universe and Stuff with tags , , , , , , , , , on November 12, 2023 by telescoper

It’s been a busy week generally, and specifically at the  Open Journal of Astrophysics. In fact, this week we have published three papers, which I didn’t have time to post here at the time we published them but now present to you. These take the count in Volume 6 (2023) up to 44 and the total published by OJAp up to 109. With many more in the pipeline we’re still on for 50 by the end of the year.

In chronological order, the three papers published this week, with their overlays, are as follows. You can click on the images of the overlays to make them larger should you wish to do so. All three of these papers are in the folder Cosmology and Nongalactic Astrophysics.

First one up is “On the degeneracies between baryons, massive neutrinos and f(R) gravity in Stage IV cosmic shear analyses” by Alessio Spurio Mancini (Mullard Space Sciences Laboratory, University College London, UK) and Benjamin Bose (Royal Observatory Edinburgh, UK). This presents a fast nonlinear matter power spectrum emulator for f(R) gravity with massive neutrinos, coupled with a baryon feedback emulator forecasts for a cosmic shear experiment with typical Stage IV specifications. This paper was published on 6th November 2023.

Here is a screen grab of the overlay, which includes the abstract:

You can find the officially accepted version of the paper on the arXiv here.

The second paper to announce is “” by Marika Asgari (Hull, UK), Alexander Mead (Bochum, Germany) and Catherine Heymans (Edinburgh, UK).  This presents a thorough discussion of the popular halo model for cosmological structure with applications, accompanied by the release of a software suite called pyhalomodel (which you can download here). The paper was also published on 7th November 2023 and you can see the overlay here:

 

 

The accepted version of this paper can be found on the arXiv here.

The last paper of this batch is  entitled “Dissecting the Thermal SZ Power Spectrum by Halo Mass and Redshift in SPT-SZ Data and Simulations” and the authors are: by Josemanuel Hernandez (Chicago), Lindsey Bleem (Chicago) , Thomas Crawford (Chicago), Nicholas Huang (Berkeley), Yuuki Omori (Chicago), Srinivasan Raghunathan (NCSA, Urbana) & Christian Reichardt (Melbourne). This paper, a study of the mass and redshift dependence of the thermal Sunyaev-Zeldovich effect in South Pole Telescope data and a comparison thereof with theoretical calculations, was published on 9th November 2023.

Here is the overlay:

 

 

You can find the full text for this one on the arXiv here.

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The Euclid Launch Kit!

Posted in Euclid, The Universe and Stuff with tags , , , , , on May 17, 2023 by telescoper

As the launch of the European Space Agency’s Euclid mission approaches, though we don’t know official launch date yet, the associated publicity machines are ramping up for the big occasion. The latest bit of merch is the Euclid Launch Kit.

Sadly, this does not allow you to build your own Falcon 9 launcher which is what I inferred from the name. What it is is an interactive PDF file that allows you to navigate around and learn things about the satellite, its orbit, its instruments and the science case. I think it’s pretty good. You can download it here. It’s over 100 MB though, so beware if you have a very slow connection.

To whet your appetite, here some graphics extracted from the launch kit. You can click on the tiles to make them bigger.

The two science images relate to weak gravitational lensing and baryon acoustic oscillations; for more details you can click on the relevant links.

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More from the Dark Energy Survey

Posted in Astrohype, The Universe and Stuff with tags , , , , , , on May 28, 2021 by telescoper

To much media interest the Dark Energy Survey team yesterday released 11 new papers based on the analysis of their 3-year data. You can find the papers together with short descriptions here. There’s even a little video about the Dark Energy Survey here:

The official press release summarizes the results as follows:

Scientists measured that the way matter is distributed throughout the universe is consistent with predictions in the standard cosmological model, the best current model of the universe.

This contrasts a bit with the BBC’s version:

The results are a surprise because they show that it is slightly smoother and more spread out than the current best theories predict.

The observation appears to stray from Einstein’s theory of general relativity – posing a conundrum for researchers.

The reason for this appears to be that the BBC story focusses on the weak lensing paper (found here; I’ll add a link to the arXiv version if and when it appears there). The abstract is here:

The parameter S8 is a (slightly) rescaled version of the more familiar parameter σ8  – which quantifies the matter-density fluctuations on a scale of 8 h-1 Mpc – as defined in the abstract; cosmic shear is particularly sensitive to this parameter.

The key figure showing the alleged “tension” with Planck is here:

The companion paper referred to in the above abstract (found here has an abstract that concludes with the words (my emphasis).

We find a 2.3σ difference between our S8 result and that of Planck (2018), indicating no statistically significant tension, and additionally find our results to be in qualitative agreement with current weak lensing surveys (KiDS-1000 and HSC).

So, although certain people have decided to hype up a statistically insignificant l discrepancy, everything basically fits the standard model…

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New Publication at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , on December 15, 2020 by telescoper

The Christmas rush is definitely upon us and papers are queuing up to be published in the Open Journal of Astrophysics. The latest publication is by Tom Kitching and Anurag Deshpande of MSSL (University College London) and Peter Taylor of JPL (Caltech). It is entitled Propagating residual biases in masked cosmic shear power spectra. This is another one for the folder marked Cosmology and Nongalactic Astrophysics.

Here is a screen grab of the overlay:

You can click on the image to make it larger should you wish to do so. You can find the arXiv version of the paper here.

When I last posted about a new OJA paper I mentioned that it seemed to be taking authors longer than usual to make revisions. There are signs now that some authors are trying to get papers off their desk before the Christmas break so we may have two or three more to publish before the year is out.

P.S. Last week I received an offer from a commercial organization to buy the Open Journal of Astrophysics. I replied politely that it is not for sale.

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New Publication at the Open Journal of Astrophysics!

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , on October 2, 2020 by telescoper

Time to announce another new paper in the Open Journal of Astrophysics. The latest publication is by Amy Louca and Elena Sellentin, both of the Sterrewacht Leiden in the The Netherlands, and is entitled The impact of signal-to-noise, redshift, and angular range on the bias of weak lensing 2-point functions. This is another one for the Cosmology and Nongalactic Astrophysics folder.

Here is a screen grab of the overlay:

You can click on the image to make it larger should you wish to do so. You can find the arXiv version of the paper here.

We actually published this one a few days ago but there was a slight delay registering the metadata and also I was very busy, so this post is a little late. With this paper, we have published as many papers so far in 2020 as we did in 2019 so with several more in the pipeline this looks like being our busiest year

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