#galaxymergers — Public Fediverse posts

Weekly Update from the Open Journal of Astrophysics – 02/05/2026

Here we are, on schedule, with another update of activity at the Open Journal of Astrophysics. Since the last update we have published a further seven papers, bringing the number in Volume 9 (2026) to 94 and the total so far published by OJAp up to 542. I checked the corresponding update for last year (on 3rd May 2025), and we’ve had an increase from 54 to 94 in papers published (about 74%) between the first four months of 2025 and the first four months of 2026.

I will continue to include the posts made on our Mastodon account (on Fediscience) to encourage you to visit it. Mastodon is a really excellent service, and a more than adequate replacement for X/Twitter (which nobody should be using); these announcements also show the DOI for each paper.

The first paper to report this week is “DESI-DR1 3 × 2-pt analysis: consistent cosmology across weak lensing surveys” by Anna Porredon (CIEMAT, Madrid, Spain) and 72 others (DESI Colllaboration). This paper was published on Tuesday 28th April in the folder Cosmology and Nongalactic Astrophysics. This paper presents a joint cosmological analysis of galaxy clustering and gravitational lensing observations, providing consistent constraints on cosmological parameters. The analysis also introduces a new blinding procedure to prevent confirmation bias. See this post for news of an important DESI milestone.

The overlay for this paper is here

You can find the officially accepted version on arXiv here and the announcement on Fediverse here:

https://fediscience.org/@OJ_Astro/116480407578621011

The second paper for this week, also published on Tuesday 28th April but in the folder High-Energy Astrophysical Phenomena is “Masers and Broad-Line Mapping Favor Magnetically-Dominated AGN Accretion Disks” by Philip F. Hopkins (Caltech, USA), Dalya Baron (Stanford U., USA) and Joanna M. Piotrowska (Caltech). This one presents a new constraint on supermassive black hole accretion disks physics, suggesting that outer regions are likely in a ‘hyper-magnetized’ state, as thermal or radiation pressure models appear inconsistent.

The overlay for this one is here:

The official version of the paper can be found on arXiv here and the Fediverse announcement here:

https://fediscience.org/@OJ_Astro/116480505354195181

Next one up, the third paper of the week, is “Galaxy mergers and disk angular momentum evolution: stellar halos as a critical test” by Eric F. Bell (U. Michigan, Ann Arbor, USA), Richard D’Souza (Vatican Observatory), Monica Valluri & Katya Gozman (U. Michigan). This was published on Wednesday 29th April in the folder Astrophysics of Galaxies. The paper argues that satellite accretion impacts the angular momentum evolution of galaxies, often causing significant reorientation. This process is detectable in Milky Way-mass galaxies so the idea is testable observationally.

The overlay for this one is here:

The final, accepted version can be found on arXiv here and the Mastodon announcement is here:

https://fediscience.org/@OJ_Astro/116486649450860283

The fourth paper this week, published on Thursday April 30th, is “Time-Dilation Methods for Extreme Multiscale Timestepping Problems” by Philip F. Hopkins and Elias R. Most (Caltech, USA). This paper is in the folder Instrumentation and Methods for Astrophysics: it presents a new method for astrophysical simulations that modulates time evolution with a variable dilation/stretch factor, improving efficiency and accuracy in modeling processes across different scales.

The overlay is here:

The finally accepted version of this paper can be found here and the Mastodon announcement follows:

https://fediscience.org/@OJ_Astro/116492226856595031

The fifth article of this week was also published on Thursday 30th April, but in the folder Astrophysics of Galaxies. The title is “Cosmic Rays on Galaxy Scales: Progress and Pitfalls for CR-MHD Dynamical Models” and the author is Philip F. Hopkins (Caltech, USA) who has three papers featured this week. The paper presents an overview of cosmic ray (CR) modeling, highlighting its influence on galactic physics and star formation. It addresses previous modeling errors and presents new methods for full-spectrum dynamics.

The overlay is here:

You can find the authorized version of this paper on arXiv here and the Fediverse announcement is here:

https://fediscience.org/@OJ_Astro/116492282488422075

The sixth paper of the week is “Baryonification III: An accurate analytical model for the dispersion measure probability density function of fast radio bursts” by MohammadReza Torkamani (Universität Bonn, Germany) and 8 others based in Germany, Switzerland, UK and Sweden. This article was also published on Thursday April 30th in the folder Cosmology and Nongalactic Astrophysics. It presents a framework for predicting dispersion measures of fast radio bursts using the baryonification model, providing a cost-effective alternative to hydrodynamical simulations. The model’s accuracy is validated through full numerical simulations. The overlay is here:

You can find the officially-accepted version on arXiv here and the Mastodon announcement here:

https://fediscience.org/@OJ_Astro/116492403170125062

Seventh and finally for this week we have “The stellar and dark matter distributions in early-type galaxies measured by stacked weak gravitational lensing” by Momoka Fujikawa and Masamune Oguri (Chiba University, Japan). This study uses weak gravitational lensing to investigate stellar mass and dark matter density in red galaxies, suggesting a stronger feedback effect than current simulations predict. This was published on Friday 1st May 2026 in the folder Astrophysics of Galaxies. The overlay is here:

You can find the officially-accepted version on arXiv here and the Fediverse announcement is here:

https://fediscience.org/@OJ_Astro/116497987401632687

And that concludes this week’s update. I’ll do another one at the end of next week. Will Vol. 9 have reached a hundred by then?

P.S. Just a reminder that, thanks to the efforts of a member of our Editorial Board, the Open Journal of Astrophysics now has a Wikipedia page.

Weekly Update from the Open Journal of Astrophysics – 02/05/2026

Here we are, on schedule, with another update of activity at the Open Journal of Astrophysics. Since the last update we have published a further seven papers, bringing the number in Volume 9 (2026) to 94 and the total so far published by OJAp up to 542. I checked the corresponding update for last year (on 3rd May 2025), and we’ve had an increase from 54 to 94 in papers published (about 74%) between the first four months of 2025 and the first four months of 2026.

I will continue to include the posts made on our Mastodon account (on Fediscience) to encourage you to visit it. Mastodon is a really excellent service, and a more than adequate replacement for X/Twitter (which nobody should be using); these announcements also show the DOI for each paper.

The first paper to report this week is “DESI-DR1 3 × 2-pt analysis: consistent cosmology across weak lensing surveys” by Anna Porredon (CIEMAT, Madrid, Spain) and 72 others (DESI Colllaboration). This paper was published on Tuesday 28th April in the folder Cosmology and Nongalactic Astrophysics. This paper presents a joint cosmological analysis of galaxy clustering and gravitational lensing observations, providing consistent constraints on cosmological parameters. The analysis also introduces a new blinding procedure to prevent confirmation bias. See this post for news of an important DESI milestone.

The overlay for this paper is here

You can find the officially accepted version on arXiv here and the announcement on Fediverse here:

https://fediscience.org/@OJ_Astro/116480407578621011

The second paper for this week, also published on Tuesday 28th April but in the folder High-Energy Astrophysical Phenomena is “Masers and Broad-Line Mapping Favor Magnetically-Dominated AGN Accretion Disks” by Philip F. Hopkins (Caltech, USA), Dalya Baron (Stanford U., USA) and Joanna M. Piotrowska (Caltech). This one presents a new constraint on supermassive black hole accretion disks physics, suggesting that outer regions are likely in a ‘hyper-magnetized’ state, as thermal or radiation pressure models appear inconsistent.

The overlay for this one is here:

The official version of the paper can be found on arXiv here and the Fediverse announcement here:

https://fediscience.org/@OJ_Astro/116480505354195181

Next one up, the third paper of the week, is “Galaxy mergers and disk angular momentum evolution: stellar halos as a critical test” by Eric F. Bell (U. Michigan, Ann Arbor, USA), Richard D’Souza (Vatican Observatory), Monica Valluri & Katya Gozman (U. Michigan). This was published on Wednesday 29th April in the folder Astrophysics of Galaxies. The paper argues that satellite accretion impacts the angular momentum evolution of galaxies, often causing significant reorientation. This process is detectable in Milky Way-mass galaxies so the idea is testable observationally.

The overlay for this one is here:

The final, accepted version can be found on arXiv here and the Mastodon announcement is here:

https://fediscience.org/@OJ_Astro/116486649450860283

The fourth paper this week, published on Thursday April 30th, is “Time-Dilation Methods for Extreme Multiscale Timestepping Problems” by Philip F. Hopkins and Elias R. Most (Caltech, USA). This paper is in the folder Instrumentation and Methods for Astrophysics: it presents a new method for astrophysical simulations that modulates time evolution with a variable dilation/stretch factor, improving efficiency and accuracy in modeling processes across different scales.

The overlay is here:

The finally accepted version of this paper can be found here and the Mastodon announcement follows:

https://fediscience.org/@OJ_Astro/116492226856595031

The fifth article of this week was also published on Thursday 30th April, but in the folder Astrophysics of Galaxies. The title is “Cosmic Rays on Galaxy Scales: Progress and Pitfalls for CR-MHD Dynamical Models” and the author is Philip F. Hopkins (Caltech, USA) who has three papers featured this week. The paper presents an overview of cosmic ray (CR) modeling, highlighting its influence on galactic physics and star formation. It addresses previous modeling errors and presents new methods for full-spectrum dynamics.

The overlay is here:

You can find the authorized version of this paper on arXiv here and the Fediverse announcement is here:

https://fediscience.org/@OJ_Astro/116492282488422075

The sixth paper of the week is “Baryonification III: An accurate analytical model for the dispersion measure probability density function of fast radio bursts” by MohammadReza Torkamani (Universität Bonn, Germany) and 8 others based in Germany, Switzerland, UK and Sweden. This article was also published on Thursday April 30th in the folder Cosmology and Nongalactic Astrophysics. It presents a framework for predicting dispersion measures of fast radio bursts using the baryonification model, providing a cost-effective alternative to hydrodynamical simulations. The model’s accuracy is validated through full numerical simulations. The overlay is here:

You can find the officially-accepted version on arXiv here and the Mastodon announcement here:

https://fediscience.org/@OJ_Astro/116492403170125062

Seventh and finally for this week we have “The stellar and dark matter distributions in early-type galaxies measured by stacked weak gravitational lensing” by Momoka Fujikawa and Masamune Oguri (Chiba University, Japan). This study uses weak gravitational lensing to investigate stellar mass and dark matter density in red galaxies, suggesting a stronger feedback effect than current simulations predict. This was published on Friday 1st May 2026 in the folder Astrophysics of Galaxies. The overlay is here:

You can find the officially-accepted version on arXiv here and the Fediverse announcement is here:

https://fediscience.org/@OJ_Astro/116497987401632687

And that concludes this week’s update. I’ll do another one at the end of next week. Will Vol. 9 have reached a hundred by then?

P.S. Just a reminder that, thanks to the efforts of a member of our Editorial Board, the Open Journal of Astrophysics now has a Wikipedia page.

Weekly Update from the Open Journal of Astrophysics – 25/04/2026

So here we are again, on a Saturday morning, with another update of activity at the Open Journal of Astrophysics. Since the last update we have published a further five papers, bringing the number in Volume 9 (2026) to 87 and the total so far published by OJAp up to 535.

I will continue to include the posts made on our Mastodon account (on Fediscience) to encourage you to visit it. Mastodon is a really excellent service, and a more than adequate replacement for X/Twitter (which nobody should be using); these announcements also show the DOI for each paper.

The first paper to report this week is “Bayesian Cosmic Void Finding with Graph Flows” by Leander Thiele (U. Tokyo, Japan). This was published on Monday 20th April in the folder Cosmology and Nongalactic Astrophysics. The paper presents a method using a deep graph neural network to identify cosmic voids in sparse galaxy surveys, improving upon traditional deterministic algorithms by considering the problem’s probabilistic nature. The overlay is here:

You can find the officially accepted version on arXiv here and the announcement on Fediverse here:

https://fediscience.org/@OJ_Astro/116435864086025246

The second paper for this week, published on Wednesday 22nd April in the folder Astrophysics of Galaxies, is “Sifting for a Stream: The Morphology of the 300S Stellar Stream” by Benjamin Cohen (U. Chicago, USA) and 20 others distributed around the world. This study analyzes the morphology of the $300S$ stellar stream, revealing three density peaks, a possible gap, and a kink, suggesting significant influence from the Large Magellanic Cloud on its structure.

The overlay for this one is here:

The official version of the paper can be found on arXiv here and the Fediverse announcement here:

https://fediscience.org/@OJ_Astro/116447005556180402

Next one up, the third paper of the week, is “IRMaGiC: Extending Luminous Red Galaxy Selection into the Infrared with Joint Rubin Observatory’s Large Survey of Space Time and Roman’s High Latitude Imaging Survey” by Zhiyuan Guo & Chris. W. Walter (Duke U., USA) and Eli S. Rykoff (Stanford U., USA) on behalf of the LSST Dark Energy Science Collaboration. This was published on Wednesday April 22nd in the folder Cosmology and Nongalactic Astrophysics. The paper introduces IRMaGiC, an algorithm that improves the selection and redshift estimation of Luminous Red Galaxies (LRGs) by incorporating infrared data, enhancing future cosmological surveys.

The overlay for this one is here:

The final, accepted version can be found on arXiv here and the Mastodon announcement is here:

https://fediscience.org/@OJ_Astro/116447067337351283

The fourth paper this week, published on Thursday April 23rd, is “The Diagnostic Temperature Discrepancy as Evidence for Non-Maxwellian Coronal Electrons” by Victor Edmonds (Final Stop Consulting, USA). This paper, in the folder Solar and Stellar Astrophysics, presents two methods of measuring electron temperature in the quiet solar corona yielding different results, suggesting non-Maxwellian electron velocity distributions may be responsible for the discrepancy.

The overlay is here:

The finally accepted version of this paper can be found here and the Mastodon announcement follows:

https://fediscience.org/@OJ_Astro/116452775389963618

The fifth and final paper for this week was published on Friday 24th April in the folder Astrophysics of Galaxies. The title is “Galaxy evolution in the post-merger regime. IV – The long-term effect of mergers on galactic stellar mass growth and distribution” by Sara L. Ellison (U. Victoria, Canada) and Leonardo Ferreira (Universidade Federal do Rio Grande, Brazil). This study uses a large sample of post-merger galaxies to demonstrate that galaxy mergers trigger significant and extended stellar mass growth in their central regions, independent of stellar population modelling.

The overlay is here:

You can find the authorized version of this paper on arXiv here and the Fediverse announcement is here:

https://fediscience.org/@OJ_Astro/116458316824739014

The overlay for this one is here:

You can find the officially-accepted version on arXiv here and the Mastodon announcement here:

https://fediscience.org/@OJ_Astro/116458316824739014

And that concludes this week’s update. I’ll do another one at the end of next week.

P.S. Thanks to the efforts of a member of our Editorial Board, the Open Journal of Astrophysics now has a Wikipedia page.

Weekly Update from the Open Journal of Astrophysics – 25/04/2026

So here we are again, on a Saturday morning, with another update of activity at the Open Journal of Astrophysics. Since the last update we have published a further five papers, bringing the number in Volume 9 (2026) to 87 and the total so far published by OJAp up to 535.

I will continue to include the posts made on our Mastodon account (on Fediscience) to encourage you to visit it. Mastodon is a really excellent service, and a more than adequate replacement for X/Twitter (which nobody should be using); these announcements also show the DOI for each paper.

The first paper to report this week is “Bayesian Cosmic Void Finding with Graph Flows” by Leander Thiele (U. Tokyo, Japan). This was published on Monday 20th April in the folder Cosmology and Nongalactic Astrophysics. The paper presents a method using a deep graph neural network to identify cosmic voids in sparse galaxy surveys, improving upon traditional deterministic algorithms by considering the problem’s probabilistic nature. The overlay is here:

You can find the officially accepted version on arXiv here and the announcement on Fediverse here:

https://fediscience.org/@OJ_Astro/116435864086025246

The second paper for this week, published on Wednesday 22nd April in the folder Astrophysics of Galaxies, is “Sifting for a Stream: The Morphology of the 300S Stellar Stream” by Benjamin Cohen (U. Chicago, USA) and 20 others distributed around the world. This study analyzes the morphology of the $300S$ stellar stream, revealing three density peaks, a possible gap, and a kink, suggesting significant influence from the Large Magellanic Cloud on its structure.

The overlay for this one is here:

The official version of the paper can be found on arXiv here and the Fediverse announcement here:

https://fediscience.org/@OJ_Astro/116447005556180402

Next one up, the third paper of the week, is “IRMaGiC: Extending Luminous Red Galaxy Selection into the Infrared with Joint Rubin Observatory’s Large Survey of Space Time and Roman’s High Latitude Imaging Survey” by Zhiyuan Guo & Chris. W. Walter (Duke U., USA) and Eli S. Rykoff (Stanford U., USA) on behalf of the LSST Dark Energy Science Collaboration. This was published on Wednesday April 22nd in the folder Cosmology and Nongalactic Astrophysics. The paper introduces IRMaGiC, an algorithm that improves the selection and redshift estimation of Luminous Red Galaxies (LRGs) by incorporating infrared data, enhancing future cosmological surveys.

The overlay for this one is here:

The final, accepted version can be found on arXiv here and the Mastodon announcement is here:

https://fediscience.org/@OJ_Astro/116447067337351283

The fourth paper this week, published on Thursday April 23rd, is “The Diagnostic Temperature Discrepancy as Evidence for Non-Maxwellian Coronal Electrons” by Victor Edmonds (Final Stop Consulting, USA). This paper, in the folder Solar and Stellar Astrophysics, presents two methods of measuring electron temperature in the quiet solar corona yielding different results, suggesting non-Maxwellian electron velocity distributions may be responsible for the discrepancy.

The overlay is here:

The finally accepted version of this paper can be found here and the Mastodon announcement follows:

https://fediscience.org/@OJ_Astro/116452775389963618

The fifth and final paper for this week was published on Friday 24th April in the folder Astrophysics of Galaxies. The title is “Galaxy evolution in the post-merger regime. IV – The long-term effect of mergers on galactic stellar mass growth and distribution” by Sara L. Ellison (U. Victoria, Canada) and Leonardo Ferreira (Universidade Federal do Rio Grande, Brazil). This study uses a large sample of post-merger galaxies to demonstrate that galaxy mergers trigger significant and extended stellar mass growth in their central regions, independent of stellar population modelling.

The overlay is here:

You can find the authorized version of this paper on arXiv here and the Fediverse announcement is here:

https://fediscience.org/@OJ_Astro/116458316824739014

The overlay for this one is here:

You can find the officially-accepted version on arXiv here and the Mastodon announcement here:

https://fediscience.org/@OJ_Astro/116458316824739014

And that concludes this week’s update. I’ll do another one at the end of next week.

P.S. Thanks to the efforts of a member of our Editorial Board, the Open Journal of Astrophysics now has a Wikipedia page.

NASA, Partners Advance LISA Prototype Hardware https://science.nasa.gov/missions/lisa/nasa-partners-advance-lisa-prototype-hardware/ #NASA #Astrophysics #BlackHoles #Galaxies #GalaxyMergers #GoddardSpaceFlightCenter #GravitationalWaves #LISALaserInterferometerSpaceAntenna #SupermassiveBlackHoles #TheUniverse

NASA, Partners Advance LISA Prototype Hardware

https://web.brid.gy/r/https://science.nasa.gov/missions/lisa/nasa-partners-advance-lisa-prototype-hardware/

Once again, it’s time for a quick update of activity at the Open Journal of Astrophysics. This week we have published another batch of four papers which takes the count in Volume 7 (2024) up to 77 and the total published altogether by OJAp up to 192. Things are picking up again after the summer lull, and we’re moving towards a double century. If we keep up a steady average of four per week we’ll be at 200 per year.

In chronological order, 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.

First one up is “Quasi-two-dimensionality of three-dimensional, magnetically dominated, decaying turbulence” by Shreya Dwivedi, Chandranathan Anandavijayan, and Pallavi Bhat of TIFR, Bangalore, India. The paper presents an analysis of numerical simulations of MHD turbulence using Minkowski Functionals, with implications for local anisotropies revealed therein. It was published on 9th September 2024 and is in the folder marked High-Energy Astrophysical Phenomena.

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, also published on 9th September 2024, is “mochi_class: Modelling Optimisation to Compute Horndeski In class” by  Matteo Cataneo (Universität Bonn, Germany) and Emilio Bellini (SISSA, Trieste, Italy). This article presents a cosmological Einstein-Boltzmann solver adapted to work with Horndeski gravity, together with validation tests. It is in the folder Cosmology and NonGalactic Astrophysics.

You can see the overlay here:

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

The third paper, published on 11th September 2024 in the folder marked High-Energy Astrophysical Phenomena, is by Jonathan Katz of Washington University, St Louis, USA. The title is “The Sources of Fast Radio Bursts” and it presents a discussion of the possible physical origin of Fast Radio Bursts, arguing that they fall into two distinct groups.

The final version accepted on arXiv is here.

Last in this batch, but by no means least, is “RMS asymmetry: a robust metric of galaxy shapes in images with varied depth and resolution” by Elizaveta Sazonova (U. Waterloo, Canada) with 15 other authors spread around the world (in Canada, USA, Australia, Italy, Chile, UK, Poland, Mexico, Germany, and Spain). This paper presents a method of quantifying distortion of galaxy images connected with mergers or other instabilities. It is in the folder marked Astrophysics of Galaxies and was published on September 12th 2024 with this overlay:

You can find the official accepted version on the arXiv here.

That’s all for now. I will post another update in a week.

https://telescoper.blog/2024/09/14/four-new-publications-at-the-open-journal-of-astrophysics-7/

#arXiv220713241v4 #arXiv240101965v2 #arXiv240405792v2 #arXiv240711968v2 #AstrophysicsOfGalaxies #CosmologyAndNonGalacticAstrophysics #EinsteinBoltzmannEquations #fastRadioBursts #galaxies #galaxyMergers #GalaxyShapes #HighEnergyAstrophysicalPhenomena #HorndeskiGravity #magnetohydrodynamics #MHD #MinkowskiFunctionals #OpenJournalOfAstrophysics #PlasmaPhysics #plasmaTurbulence #TheOpenJournalOfAstrophysics