News came out yesterday of the results of the latest funding prioritization exercise by the UK Science and Technology Facilities Council (STFC). The total savings being made by cuts to astronomy and particle physics are less than the funds allocated to just one AI lab! It seems STFC has to bear the brunt of savings needed so that UKRI, the organization under which STFC sits, can gamble much more on Artificial Intelligence and Quantum Technology. It seems to me that these are two bubbles ready to burst and the decision to sink money into them is not only unwise, it places the UK science base at serious risk of collapse.
Anyway, you can find the list of specific cuts here. Radio astronomy is hit particularly hard. The interferometric network e-Merlin is not prioritized and its funding will run out in 2028. That puts Jodrell Bank Observatory in danger of complete closure unless an alternative source of funding can be found. The last time STFC had a financial crisis was in 2009 and e-Merlin might well have been cut then but survived thanks to political intervention at the highest level. I suppose that could happen again, but I wouldn’t bet on it. More bad news is that the UK Square Kilometre Array Regional Centre, with SKA itself already financially troubled, is also earmarked for cuts.
The 76m Lovell Telescope at Jodrell Bank, now under threat of closure
And that’s just radio astronomy and Jodrell Bank is one of the highest-profile casualties. There are cuts and cancellations in many other areas too; see here for a full list.
The Astronomer Royal for Scotland, Catherine Heymans, has used her platform to campaign against these damaging and short-sighted cuts to UK astronomy, including on social media:
Just off #BBCR4 World at One, arguing the importance of discovery science (like Jodrell) for long-term economic growth. I said I was heartbroken at the news: evidence just look at how exceptionally excited me & @mamaphysikerin.bsky.social were when we got to stand inside Lovell back in 2017 ๐ฅฐ ๐ญ๐งช
The same can’t be said for the Astronomer Royal herself, Prof. Michele Dougherty. The reason for that is Prof. Dougherty is also Executive Chair of STFC and is therefore responsible for implementing the cuts. How it is possible for her to remain in both posts is nothing short of a scandal. Such a glaring conflict of interest cannot be allowed to stand. Indeed, Prof. Dougherty was elected to serve as President of the Institute of Physics from October 2025 but stepped down in January 2026 citing concerns of a conflict of interest with her role at STFC. It’s a slap in the face to the Astronomy community that it is not deemed worthy of such consideration.
It’s time once more for another Saturday update of activity at theย Open Journal of Astrophysics.ย Since theย last updateย we have published a further nine papers, bringing the number inย Volume 9 (2026)ย to 160 and the total so far published by OJAp up to 608.
I will continue to include the posts made on our Mastodon account (on Fediscience); these announcements also show the DOI for each paper.
The first paper to report this week was published on Tuesday 21st July in the folder Cosmology and Nongalactic Astrophysics. The title is “Characterization of the Polarization Beam Response of SPT-3G Using Point Sources” by Tijmen de Haan (Institute of Particle and Nuclear Studies, Ibaraki, Japan) and an international cast of 101 others. This study presents measurements of the South Pole Telescope’s polarized beam response, indicating minimal sidelobe depolarization. The findings suggest potential explanations for frequency-dependent residuals in power spectrum analysis.
The overlay for this paper is here
You can find the officially accepted version on arXiv here and the announcement on Fediverse here:
New Publication at the Open Journal of Astrophysics: "Characterization of the Polarization Beam Response of SPT-3G Using Point Sources" by Tijmen de Haan (Institute of Particle and Nuclear Studies, Ibaraki, Japan) and 101 others from around the world
The second paper for this week, also published on Tuesday 21st July but in the folder Earth and Planetary Astrophysics is: “Exploring TRAPPIST-1 Climate States with an Energy Balance Model” by Jacob Haqq-Misra (Blue Marble Space, USA). The study uses a modified HEXTOR energy balance model to predict climate states of terrestrial planets orbiting low-mass stars, suggesting partial to complete ice cover for TRAPPIST-1 e and f.Abstractfor Exploring TRAPPIST-1 Climate States with an Energy Balance Model.
The overlay looks like this:
The official version of the paper can be found on arXiv here and the Fediverse announcement here:
New Publication at the Open Journal of Astrophysics: "Exploring TRAPPIST-1 Climate States with an Energy Balance Model" by Jacob Haqq-Misra (Blue Marble Space, USA)
New Publication at the Open Journal of Astrophysics: "A first systematic study of [OIII] 88ฮผm at z>8: two luminous oxygen lines and a powerful ionized outflow in the first 600 million years" by Hiddo Algera (Institute of Astronomy and Astrophysics, Taipei, Taiwan) and 37 others from all around the world.
The fourth paper of the week, published on Thursday 23rd July in the folder Astrophysics of Galaxies, is “Mapping CO Ice in a Star-Forming Filament in the 3 kpc Arm with JWST” by Savannah Gramze (U. Florida, USA) and 16 others based all around the world. This paper shows that JWST observations and ALMA Band 3 data reveal that 50-88% of CO gas in a star-forming filament is locked in ice; corrections are needed for mass measurements in such systems.
The overlay for this one is here:
You can read the final version of this one on arXiv here and the Mastodon announcement is here:
New Publication at the Open Journal of Astrophysics: "Mapping CO Ice in a Star-Forming Filament in the 3 kpc Arm with JWST" by Savannah Gramze (U. Florida, USA) and 16 others based all around the world.
New Publication at the Open Journal of Astrophysics: "Viscously Spreading Accretion Disks around Black Holes: Implications for TDEs, LFBOTs and other Transients" by Mila Winter-Granic and Eliot Quataert (Princeton University, USA)
The sixth paper of this week is “Characterising the response of an International LOFAR Station” by Letizia Vincetti (Trinity Collge Dublin, Ireland) and 9 others based in Ireland, USA, The Netherlands and Sweden. This was also published on Thursday July 23rd and is in the folder Instrumentation and Methods for Astrophysics. The article presents an investigation of the performance and calibration challenges of phased-array radio interferometers, using the Irish LOFAR station as a case study, highlighting the importance of accurate beam modelling, etc.
The overlay for this one is here:
You can find the final accepted version on arXiv here and the Mastodon announcement is here:
New Publication at the Open Journal of Astrophysics: "Characterising the response of an International LOFAR Station" by Letizia Vincetti (Trinity Collge Dublin, Ireland) and 9 others based in Ireland, USA, The Netherlands and Sweden
New Publication at the Open Journal of Astrophysics: "Exo Skryer: A JAX-accelerated sub-stellar atmospheric retrieval framework" by Elspeth K.H. Lee (U. Bern, Switzerland)
New Publication at the Open Journal of Astrophysics: "GCR Spectra Reconstructed with Neutron Monitor Yield Function and Artificial Neural Networks: Comparison of Two Methods" by Stepan A. Siruk (Moscow Engineering Physics Institute MEPhI, Russia) and four others based in Russia
And finally for this week we have “The failed failed-supernova scenario of M31-2014-DS1” by Noam Soker (Technion, Israel), a paper which challenges the failed-supernova theory for the fading of the yellow supergiant event M31-2014-DS1, suggesting it requires unlikely parameters and supports an alternative scenario involving violent binary interaction. This was published on Friday 24th July in the folder High-Energy Astrophysical Phenomena.
The overlay for this one is here:
You can find the final accepted version on arXiv here and the Mastodon announcement is here:
And that concludes the update of this week’s business. As it was foretold, the total number of publications at OJAp has now passed the 600 mark, and the likely number for 2026 is around 300. We published a paper in five of the six astro-ph categories this week, but still haven’t had a week when we’ve published a full house with at least one in all six…
It’s time once more for another Saturday update of activity at the Open Journal of Astrophysics. Since the last update we have published a further six papers, bringing the number in Volume 9 (2026) to 151 and the total so far published by OJAp up to 599.
I will continue to include the posts made on our Mastodon account (on Fediscience); these announcements also show the DOI for each paper.
The first paper to report this week, published on Tuesday 14th July, is “On combining estimated and analytic covariance matrices” by Alan Heavens (Imperial College London, UK), Lorne Whiteway (University College, London, UK) and Elena Sellentin (Leiden University, The Netherlands). This article, published in the folder Cosmology and Nongalactic Astrophysics, presents an accurate approximation for the combined likelihood function in cosmological data analysis, improving upon previous methods by better representing the heavy tails of the true distribution.
The overlay for this paper is here
You can find the officially accepted version on arXiv here and the announcement on Fediverse here:
New Publication at the Open Journal of Astrophysics: "On combining estimated and analytic covariance matrices" by Alan Heavens (Imperial College London, UK), Lorne Whiteway (University College, London, UK) and Elena Sellentin (Leiden University, The Netherlands)
The second paper for this week, also published on Tuesday 14th July in the folder Cosmology and Nongalactic Astrophysics is: “Line-of-sight shear in SLACS strong lenses II: validation tests with an extended sample” by Natalie B. Hogg (U. Cambridge, UK), Daniel P. Johnson (Universitรฉ de Montpellier, France), Anowar J. Shajib (U. Chicago, USA) and Julien Larena (Montpellier). The study described in this paper models 27 additional gravitational lenses, finding a significant fraction with unexpectedly large line-of-sight shears. Factors like redshift, filter, and signal-to-noise ratio don’t significantly affect shear magnitudes.
The overlay looks like this:
The official version of the paper can be found on arXiv here and the Fediverse announcement here:
New Publication at the Open Journal of Astrophysics: "Line-of-sight shear in SLACS strong lenses II: validation tests with an extended sample" by Natalie B. Hogg (U. Cambridge, UK), Daniel P. Johnson (Universitรฉ de Montpellier, France), Anowar J. Shajib (U. Chicago, USA) and Julien Larena (Montpellier)
New Publication at the Open Journal of Astrophysics: "Investigating the Dark Energy Constraint from Strongly Lensed AGN at LSST-Scale" by Sydney Erickson (Stanford University, USA) and 13 others on behalf of The LSST Dark Energy Science Collaboration
New Publication at the Open Journal of Astrophysics: "University of Hawaii 88-inch Telescope Observations of the Interstellar Comet 3I/ATLAS: Spectrophotometric Blue-Sensitive Spectral Time Series Spanning Two Months from Discovery" by W. B. Hoogendam (University of Hawaii, USA) and 24 others from around the world.
The fifth paper of the week, published on Friday 17th July in the folder Astrophysics of Galaxies, is “The birth of the intracluster medium: the evolution of multiphase gas and Lyman-ฮฑ haloes in a z~3 simulated protocluster” by Jake S. Bennett (Harvard Smithsonian CfA, USA), Aaron Smith (U. Nottingham, UK), Fabrizio Arrigoni-Battaia (MPA Garching, Germany), Debora Sijacki (U. Cambridge, UK) , Cassandra Lochhaas (CfA) and Lars Hernquist (CfA). This study uses a cosmological simulation to explore the transition from complex galactic haloes to mature galaxy clusters, focusing on gas distribution, ionisation, and emission changes during this evolution.
The overlay for this one is here:
You can read the final version of this one on arXiv here and the Mastodon announcement is here:
New Publication at the Open Journal of Astrophysics: "The birth of the intracluster medium: the evolution of multiphase gas and Lyman-ฮฑ haloes in a z~3 simulated protocluster" by Jake S. Bennett (Harvard Smithsonian CfA, USA), Aaron Smith (U. Nottingham, UK), Fabrizio Arrigoni-Battaia (MPA Garching, Germany), Debora Sijacki (U. Cambridge, UK) , Cassandra Lochhaas (CfA) and Lars Hernquist (CfA).
The sixth and final paper of this week is “Density reconstruction from biased tracers: Testing the equivalence principle through consistency relations” by Lawrence Dam and Omar Darwish (Universitรฉ de Genรจve, Switzerland). This was published on Friday 17th July in the folder Cosmology and Nongalactic Astrophysics. It proposes using quadratic estimators to test the weak equivalence principle on cosmological scales, offering a practical alternative to the conventional bispectrum approach.
The overlay for this one is here:
You can find the final accepted version on arXiv here and the Mastodon announcement is here:
New Publication at the Open Journal of Astrophysics: "Density reconstruction from biased tracers: Testing the equivalence principle through consistency relations" by Lawrence Dam and Omar Darwish (Universitรฉ de Genรจve, Switzerland)
As you can see we have now published over 150 papers this year and are just one shy of 600 in total. I expect we’ll pass that milestone next week. I’ll do another update next Saturday.
Back into the swing of things in Maynooth, getting ready for the repeat examinations that start next month, I realized that I had forgotten to pass on an interesting paper that I found out about a few weeks ago but was reminded of while in London so I’m remedying my omission now. The title is The Coherence Principle: A Falsifiable Prior for Model Selection from the Grammar of Theories by Raul Jimenez, Carlos Peรฑa Garay, Fergus Simpson, and Licia Verde. It addresses the issue of how to assign prior probabilities. We know how to do this in cases where the models concerned belong to a family differentiated by relatively simple parameters (as is the case in the standard cosmological framework), but for more complex differences the appropriate prior is difficult to choose. I see the paper as an attempt to extend the work of Ed Jaynes, though I’m not sure the authors see it quite in those terms!
Here is the abstract:
Bayesian model selection in cosmology and particle physics is often performed where posterior odds inherit a strong, often unacknowledged dependence on the prior assigned to competing models. Standard responses — reference priors, hierarchical priors, or appeals to naturalness — ignore relevant theoretical knowledge or rely on criteria hard to define operationally. We propose the Coherence Principle: a reproducible prescription for assigning model priors according to compatibility with the validated structure of an existing theory. This structure, grammar, includes symmetries, conservation laws, locality, Lorentz invariance, and universality patterns. Unmotivated violations of these rules incur a coherence cost, converted into a prior weight through a maximum-entropy exponential form controlled by one calibratable parameter ฮฑ. The resulting prior is distinct from both the Bayesian Occam factor and naturalness: it penalizes not parameter volume or fine tuning, but departures from validated theoretical grammar. We illustrate the principle with examples from cosmology and fundamental physics: neutrino mass mechanisms, dark energy and modified gravity, inflation, beyond-Standard-Model sectors, and hierarchical astrophysical inference. We test it also on four historical cases — general relativity, Pauli’s neutrino, parity violation, and special relativity — where evidential and theoretical contexts can be reconstructed. These examples show that it favors the historically successful choice when the proper grammar is defined in the correct domain and time. The Coherence Principle makes explicit a common but usually tacit part of physical reasoning: trust in validated structural rules. It turns this judgment into a transparent, testable, and overrulable component of Bayesian inference, leaving empirical likelihoods free to dominate when data are sufficiently constraining.
I was very sad this morning to read the news that Sam Neill has passed away at the age of 78. He was a very fine and exceptionally versatile actor. Among many other roles I remember him well as the sadistic and corrupt Chief Inspector Chester Campbell in Peaky Blinders. I was impressed by his convincing Ulster accent but then found out he was actually born in Omagh, County Tyrone.
About 25 years ago (!) I made a very brief appearance in a BBC documentary series called Space for which Sam Neill (left) was the narrator. Apparently he only agreed to do the job on condition that they would film his segments at his home in New Zealand. I remember talking to the production team about Sam Neill and they all said he was not only very professional in his work but also a very nice man. These things don’t always go together…
After the episode I was in – the last of six – was broadcast, my Mam rang me. She didn’t mention my part at all, but asked “That Sam Neill, is he nice?”. I had to explain that I never met him, as they filmed his segments after all the other location sequences. “Oh well,” she said. “At least he knows your name”.
The following clip shows the item I took part in. Originally we were going to demonstrate wormholes using a snooker table, clever editing and reversed video. The producer, Jeremy Turner, decided that wouldn’t look spectacular enough so instead we went to St Anton in Austria: I was flown over the Alps in a helicopter and then driven through the Arlberg tunnel in an impressively fast car. Well worth the cost to license fee payers, I’m sure, even if the three-day trip to Austria by me and a crew of six as well as the hire of the helicopter ended up as a mere three minutes of screen time.
The item is daft, I know, and I don’t really believe any of that stuff about wormholes. It was great fun doing it, but hard work. I remember after the shoot we had a few drinks to wrap it up then left on a very early flight the next morning to the UK. I got back to Nottingham University just in time for a 10am lecture.
Anyway, the episode I was in was called To Boldly Go. I remember suggesting to the producer that the only way to travel faster than light in the manner required was with a split infinitive drive, but they didn’t use that in the final script.
Notice how, in the helicopter sequence, I give the appearance of being completely terrified. A fine piece of acting by me, I thought. *Cough*
Back home to Maynooth, just in time for another Saturday update of activity at theย Open Journal of Astrophysics.ย Since theย last updateย we have published a further nine papers, bringing the number inย Volume 9 (2026)ย to 145 and the total so far published by OJAp up to 593.
I will continue to include the posts made on our Mastodon account (on Fediscience); these announcements also show the DOI for each paper.
The first paper to report this week, published on Tuesday 7th July, is “The Information Content of Quasar Variability Light Curves: How Well Can we Infer Stochastic Model Parameters?” by Brendon Brewer (U. Auckland, NZ), Geraint F. Lewis (U. Sydney, AU), Xiang Yu & Yuan Li (Auckland). Published in the folder Astrophysics of Galaxies, this study suggests that quasar variability studies should focus on the short term volatility parameter, as it’s more informative than the variability timescale. Volatility decreases with redshift suggesting intrinsic effects.
The overlay for this paper is here
You can find the officially accepted version on arXiv here and the announcement on Fediverse here:
New Publication at the Open Journal of Astrophysics: "The Information Content of Quasar Variability Light Curves: How Well Can we Infer Stochastic Model Parameters?" by Brendon Brewer (U. Auckland, NZ), Geraint F. Lewis (U. Sydney, AU), Xiang Yu & Yuan Li (Auckland)
The second paper for this week, also published on Tuesday 7th July, but in the folder High-Energy Astrophysical Phenomena, is “Cygnus X-3 as a PeVatron and the LHAASO 2025 data” by Michael Kachelriess & E. Lammert (NTNU, Trondheim, Norway). This paper suggests that the high-mass X-ray binary Cygnus X-3 can accelerate cosmic rays beyond PeV energies, contributing to a photon flux peaking around PeV energies.
The overlay looks like this:
The official version of the paper can be found on arXiv here and the Fediverse announcement here:
New Publication at the Open Journal of Astrophysics: "Cygnus X-3 as a PeVatron and the LHAASO 2025 data" by Michael Kachelriess & E. Lammert (NTNU, Trondheim, Norway)
New Publication at the Open Journal of Astrophysics: "The DESI DR1 Peculiar Velocity Survey: growth rate measurements from galaxy and momentum correlation functions" by Ryan J Turner (Swinburne Institute of Technology, Australia) and 63 others from around the world.
New Publication at the Open Journal of Astrophysics: "On the effective spin-mass ratio relation of binary black hole mergers that evolved in isolation" by Sambaran Banerjee (Helmholtz-Instituts fรผr Strahlen und Kernphysik, Germany) and Aleksandra Olejak (MPA Garching, Germany)
The fifth paper of the week, also published on Wednesday 8th July but in the folder Astrophysics of Galaxies, is “On the connection between galaxy orientation and halo absorption properties” by Rohan Venkat, Soo May Wee, and Hsiao-Wen Chen (U. Chicago, USA). This article investigates the azimuthal dependence of metal-line absorption in the circumgalactic medium of 87 isolated galaxies. The results show no significant correlation between absorption strength and azimuthal angle.
The overlay for this one is here:
You can read the final version of this one on arXiv here and the Mastodon announcement is here:
The sixth paper of this week is “Searching for Periodicity in FRB 20240114A” by Jonathan I Katz (Washington U., USA). This was published on Thursday 9th July in the folder High-Energy Astrophysical Phenomena. The study described in this paper observed FRB 20240114A, an active Fast Radio Burst, but found no significant periodicity in its bursts, contradicting magnetar models predictions.
The overlay for this one is here:
You can find the final accepted version on arXiv here and the Mastodon announcement is here:
The seventh article for this week is “Multiphase gas in Circumgalactic cloud complexes: Insights from kiloparsec-scale Magnetohydrodynamic Turbulence Simulations” by Rajsekhar Mohapatra (Princeton U., USA), Alankar Dutta (MPA Garching, Germany) and Prateek Sharma (Indian Institute of Science, Bangalore). This -paper was also published on Thursday 9th July, in the folder Astrophysics of Galaxies. This paper uses high-resolution simulations to investigate the mass distribution of the circumgalactic medium (CGM), a diffuse gas surrounding a galaxy’s halo with small-scale clumps of cold gas forming in quiescent regions.
The overlay for this one is here:
You can find the final accepted version of this one on arXiv here and the Mastodon announcement is here:
New Publication at the Open Journal of Astrophysics: "Multiphase gas in Circumgalactic cloud complexes: Insights from kiloparsec-scale Magnetohydrodynamic Turbulence Simulations" by Rajsekhar Mohapatra (Princeton U., USA), Alankar Dutta (MPA Garching, Germany) and Prateek Sharma (Indian Institute of Science, Bangalore)
The (penultimate) eighth article for this week is “Line-of-sight shear in SLACS strong lenses I: shear and mass model parametrisations” by Natalie B. Hogg (U. Cambridge, UK), Daniel Johnson (U. Montpellier, France), Anowar J. Shajib (U. Chicago, USA) and Julien Larena (Montpellier). This was also published on Thursday 9th July, but in the folder Cosmology and Nongalactic Astrophysics. This article studies models of 23 strong gravitational lenses to measure line-of-sight shear for the first time, providing potential new constraints on cosmological parameters.
The overlay for this one is here:
You can find the final accepted version on arXiv here and the Mastodon announcement is here:
New Publication at the Open Journal of Astrophysics: "Line-of-sight shear in SLACS strong lenses I: shear and mass model parametrisations" by Natalie B. Hogg (U. Cambridge, UK), Daniel Johnson (U. Montpellier, France), Anowar J. Shajib (U. Chicago, USA) and Julien Larena (Montpellier)
The ninth and last article for this week is “Current and future constraints on the expansion history of the GREA model” by Irene Graziotti (INAF-Osservatorio Astronomico di Capodimonte, Italy), Chiara De Leo (Sapienza University of Rome, Italy) and Matteo Martinelli (INAF-Osservatorio Astronomico di Roma, Italy). This study explores the General Relativistic Entropic Acceleration (GREA) framework, comparing it to the standard description of the universe. Current data favors the standard model, but GREA remains competitive.
The overlay for this one is here:
You can find the officially-accepted version on arXiv here and the Mastodon announcement here:
New Publication at the Open Journal of Astrophysics: "Current and future constraints on the expansion history of the GREA model" by Irene Graziotti (INAF-Osservatorio Astronomico di Capodimonte, Italy), Chiara De Leo (Sapienza University of Rome, Italy) and Matteo Martinelli (INAF-Osservatorio Astronomico di Roma, Italy)
As you can see, it has been a bumper week, especially when you consider that there was no arXiv mailing om Monday July 6th owing to the July 4th holiday in the USA. I should have known this would happen while I was travelling!
It’s Saturday again so it’s time for 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 136 and the total so far published by OJAp up to 584.
I will continue to include the posts made on our Mastodon account (on Fediscience); these announcements also show the DOI for each paper.
The first paper to report this week, published on Monday 29th June, is “Analysis and implications of the spatio-spectral morphology of the Fermi Bubbles” by Ami Tank (Indian Institute of Technology) and Roland Crocker & Mark R. Krumholz (Australian National University). Published in the folder High-Energy Astrophysical Phenomena, this paper presents an analysis of the gamma-ray structures of Fermi Bubbles in the Milky Way using a decade of data. The research suggests either hadronic or leptonic processes can explain the data.
The overlay for this paper is here
You can find the officially accepted version on arXiv here and the announcement on Fediverse here:
New Publication at the Open Journal of Astrophysics: "Analysis and implications of the spatio-spectral morphology of the Fermi Bubbles" by Ami Tank (Indian Institute of Technology) and Roland Crocker & Mark R. Krumholz (Australian National University)
The second paper for this week, also published on Monday 29th June, but in the folder Cosmology and Nongalactic Astrophysics, is “A first measurement of baryonic feedback with Fast Radio Bursts” by Robert Reischke (Universitรคt Bonn, Germany) and Steffen Hagstotz (Ludwig-Maximilians Universitรคt Mรผnchen, Germany). This paper argues that Fast Radio Bursts (FRBs) provide a new method to trace baryon distribution and feedback in the cosmos, offering insights into matter distribution and rejecting no-feedback scenarios with high confidence.
The overlay looks like this:
The official version of the paper can be found on arXiv here and the Fediverse announcement here:
New Publication at the Open Journal of Astrophysics: "A first measurement of baryonic feedback with Fast Radio Bursts" by Robert Reischke (Universitรคt Bonn, Germany) and Steffen Hagstotz (Ludwig-Maximilians Universitรคt Mรผnchen, Germany)
The third paper of the week, published on Tuesday 30th June in the folder High-Energy Astrophysical Phenomena, is “Idealized Global Models of Accretion Disks with Strong Toroidal Magnetic Fields” by Minghao Guo & Eliot Quataert (Princeton U., USA), Jonathan Squire (U. Otago, NZ), Philip F. Hopkins (Caltech, USA) and James M. Stone (Princeton). This study uses global magnetohydrodynamic simulations to explore the behavior of idealized accretion disks with strong toroidal magnetic fields, finding that these systems maintain a moderately strong mean azimuthal field.
The overlay for this one is here:
The final, accepted version can be found on arXiv here and the Mastodon announcement is here:
New Publication at the Open Journal of Astrophysics: "Idealized Global Models of Accretion Disks with Strong Toroidal Magnetic Fields" by Minghao Guo & Eliot Quataert (Princeton U., USA), Jonathan Squire (U. Otago, NZ), Philip F. Hopkins (Caltech, USA) and James M. Stone (Princeton)
The fourth paper of the week, published on Tuesday 30th June in the folder High-Energy Astrophysical Phenomena, is “On the effective spin-mass ratio relation of binary black hole mergers that evolved in isolation” by Sambaran Banerjee (Helmholtz-Instituts fรผr Strahlen und Kernphysik, Germany) and Aleksandra Olejak (MPA Garching, Germany). This study explores mechanisms of binary black hole mergers and finds that certain spin and mass ratio trends can be naturally explained by isolated binary evolution. The overlay for this one is here:
You can read the final version of this one on arXiv here and the Mastodon announcement is here:
New Publication at the Open Journal of Astrophysics: "On the effective spin-mass ratio relation of binary black hole mergers that evolved in isolation" by Sambaran Banerjee (Helmholtz-Instituts fรผr Strahlen und Kernphysik, Germany) and Aleksandra Olejak (MPA Garching, Germany)
The fifth paper of the week, also published on Tuesday 30th June but in the folder Solar and Stellar Astrophysics is “A systematic survey for hypervelocity runaways from thermonuclear supernovae” by Kareem El-Badry (Caltech, USA), and 18 others based in the USA, Germany, Austria and the UK. This paper presents a systematic survey of hypervelocity runaways, resulting from white dwarf explosions in binary systems. The findings suggest a diversity of remnant masses, ages, and heating mechanisms, challenging theoretical models.
The overlay for this one is here:
You can read the final version of this one on arXiv here and the Mastodon announcement is here:
New Publication at the Open Journal of Astrophysics: "A systematic survey for hypervelocity runaways from thermonuclear supernovae" by Kareem El-Badry (Caltech, USA), and 18 others based in the USA, Germany, Austria and the UK.
The sixth and penultimate paper of this week is “Boris and Exponential Integrators in the Theory of Particles Interacting with Magnetic Turbulence” by Andreas Shalchi (U. Manitoba, Canada). This was published on Wednesday 1st July, in the folder Solar and Stellar Astrophysics (it is posted in the plasma physics section of aXiv but cross-listed in solar and stellar astrophysics). The study compares the Rodrigues and Boris integrators in test-particle simulations of charged particles interacting with magnetic fields, finding both methods yield similar results.
The overlay for this one is here:
You can find the final accepted version on arXiv here and the Mastodon announcement is here:
New Publication at the Open Journal of Astrophysics: "Boris and Exponential Integrators in the Theory of Particles Interacting with Magnetic Turbulence" by Andreas Shalchi (U. Manitoba, Canada)
The seventh and final paper for this week is “Inflation at the End of 2025: Constraints on $r$ and $n_S$ using the Latest CMB and BAO Data” by Lennart Balkenhol (Institut dโAstrophysique de Paris, France) and 12 others based in France, Italy, Switzerland, UK, USA and Australia. This was also published on Wednesday 1st July, in the folder Cosmology and Nongalactic Astrophysics. This study presents constraints on parameters of inflationary models in cosmology, using the latest cosmic microwave background and baryon acoustic oscillation data. The findings help differentiate between inflation models.
The overlay for this one is here:
You can find the final accepted version of this one on arXiv here and the Mastodon announcement is here:
New Publication at the Open Journal of Astrophysics: "Inflation at the End of 2025: Constraints on $r$ and $n_S$ using the Latest CMB and BAO Data" by Lennart Balkenhol (Institut dโAstrophysique de Paris, France) and 12 others based in France, Italy, Switzerland, UK, USA and Australia.
And that concludes this week’s update. We’re starting to catch up on the backlog generated in June. At just past the halfway point of the year, which is where we are, we’re on 136 papers, which suggests a total around 272 for the year.
The latest in a sequence of claims of very large scale structures in the distribution that violate the cosmological principle emerged a week or so ago with a paper in Nature. The paper is behind a paywall but here is the abstract:
I’ve been nudged a few times by various people to comment on that but I’ve been busy recently and didn’t have time to look at the paper in detail. I had a quick look today and the thing that immediately struck me was that I didn’t understand the mock catalogues they used to compare the ฮCDM model with the observations. I still don’t understand that but I’ve stopped worrying about it because today I received a preprint (not behind a paywall, but on arXiv) from Till Sawala with the title The local galaxy distribution does not violate the cosmological principle and the (rather devastating) abstract:
The cosmological principle, which states that the Universe is statistically homogeneous and isotropic on sufficiently large scales, is a foundational assumption of the standard cosmological model. A recent analysis of DESI DR1 galaxy samples reported coherent anisotropic features in the local galaxy distribution extending to gigaparsec scales. If correct, this result would directly contradict the cosmological principle and motivate inhomogeneous cosmologies. Here I analyse the same data and compare them with galaxy distributions predicted by the FLAMINGO cosmological hydrodynamic simulation, performed in the standard ฮCDM paradigm. I show that the apparent anomaly disappears when the correct comoving distance scale is used. I also show that, rather than violating the cosmological principle, the observed structures are consistent with those expected in a ฮCDM Universe.
Here’s Figure 9 of the Sawala paper.
It seems that the authors of the Nature paper, Francesco Sylos Labiniย and Marco Galoppo, misinterpreted the distances of galaxies in the DESI DR1 sample in a way which boils down to an error of a factor (1+z)/h, where z is the redshift and h represents the Hubble constant. This hugely increases the scale and distorts the pattern of galaxy clustering. Using the correct comoving distance the measured structures are completely consistent with ฮCDM.
Oops!
P.S. I’ve stopped worrying about the mock surveys…
So here I am, in that London. I’m attending a small meeting called A Random Universe which is celebrating the occasion of the 60th Birthday of cosmologist Andrew Jaffe. The meeting is being held at South Kensington Technical Imperial College and covers cosmology, statistics, topology, and a number of other things. The title comes from a book Andrew has published:
I’m ashamed to admit I haven’t read it yet – it was published last year – but I will do. An amusing thing is that I wanted to use that title for a book I wrote some time ago but the publisher rejected it! I also noticed just now that the book uses the definite article whereas the conference has the indefinite article.
I had other things to do yesterday so I missed the first day of the meeting, and my train into London was delayed by an hour because of “a cow on the line”, which necessitated a lengthy diversion via Coventry, so I missed much of this morning too. I did make some use of the time, though, publishing three papers in the Open Journal of Astrophysics using a commendably stable Wi-Fi connection on the train.
One thing I didn’t miss, however, was an interesting panel discussion under the title AI and Inference. There wasn’t much about inference in the discussion, but it did cover some interesting ground. Cosmologists are well used to Machine Learning, which is often claimed to be a form of Artificial Intelligence, though I wouldn’t classify it as such. In fact,the large survey analyses that constitute a major part of contemporary cosmological research would not be feasible without the deployment of machine learning methods. I think it’s likely that newer methods of Generative AI and Agentic systems based on Large Language Modules will lead to increases in scientific productivity in the short term too. Whatever happens in the longer term, several years in the future, is very hard to predict, but is likely to invilve big changes in the way science is done. I’ll just say that I’m not sorry that I will be retiring in two years!
Apparently the “Holy Grail” of the Tech Bros is to find ways of creating artificial “General Intelligence”. There was an audience vote about whether this would be accomplished with the five years or so some claim. I abstained, on the grounds that I really don’t know what “General Intelligence” is supposed to mean in the first place. I would also remind readers that the Holy Grail was an object of dubious significance the Quest for which consumed considerable resources and ultimately failed.
Another topic that came up is whether AI methods will ever be truly creative. This is an interesting question because I don’t think we know very much about how creativity in any form, including the intuitive leaps that have led to advances in science, arises in human brains. I wrote a post about “Light-bulb” moments here.
One immediate effect of LLMs on science is in the publishing world. At OJAp we are experiencing a tidal wave of AI-generated slop and other garbage. This is very wearisome and I think will only get worse. We don’t rule out the use of AI in papers at OJAp, but authors must disclose what they have done and how they have tested it. Things may change in the future, but I think that in the current era of science the big problem is not that AI methods can’t be used by good scientists for good research but that AI methods make it far too easy for fools to generate superficially plausible nonsense. I don’t see any easy solution to this but maybe there is an upside, in that will hasten the end of the system of academic publishing which has in any case long outlined its usefulness.
It’s Saturday again so it’s time for another update of activity at theย Open Journal of Astrophysics.ย Since theย last updateย we have published a further three papers, bringing the number inย Volume 9 (2026)ย to 129 and the total so far published by OJAp up to 577.
I will continue to include the posts made on our Mastodon account (on Fediscience); these announcements also show the DOI for each paper.
The first paper to report this week, published on Tuesday 23rd June, is “Interpretable machine learning of halo gas density profiles: a sensitivity analysis of cosmological hydrodynamical simulations” by Daniele Sorini & Sownak Bose (Durham University, UK), Mathilda Denison (U. Penn., USA) and Romeel Davรฉ (University of Edinburgh, UK). This study uses cosmological hydrodynamical simulations and a random forest algorithm to understand how feedback processes affect the gas distribution in galaxies by predicting gas density profiles in various models. It is published in the folder Astrophysics of Galaxies.
The overlay for this paper is here
You can find the officially accepted version on arXiv here and the announcement on Fediverse here:
New Publication atthe Open Journal of Astrophysics: "Interpretable machine learning of halo gas density profiles: a sensitivity analysis of cosmological hydrodynamical simulations" by Daniele Sorini & Sownak Bose (Durham U., UK), Mathilda Denison (U. Penn., USA) and Romeel Davรฉ (U. Edinburgh, UK)
The second paper for this week, published on Wednesday June 24th in the folder Astrophysics of Galaxies is “Dual-disk galaxies and thermal states of circumgalactic medium” by Masafumi Noguchi (Tohoku University, Japan). This paper explores the suggestion that the transition from thick to dual-disk galaxies is influenced by thermal changes in the circumgalactic medium (CGM), which also affects star formation.
The overlay looks like this:
The official version of the paper can be found on arXiv here and the Fediverse announcement here:
New Publication at the Open Journal of Astrophysics: "Dual-disk galaxies and thermal states of circumgalactic medium" by Masafumi Noguchi (Tohoku University, Japan).
New Publication at the Open Journal of Astrophysics: "Mass Transfer in Tidally Heated Stars Orbiting Massive Black Holes and Implications for Repeating Nuclear Transients" by Philippe Z. Yao and Eliot Quataert (Princeton University, USA)
And that concludes this week’s update. It has been another slow week on the publishing front. We have a steadily growing backlog of papers accepted for publication but with final versions yet to appear on arXiv. I suppose it’s the holidays…
P.S. The other day I checked the stats for the Open Journal of Astrophysics and saw that we’ve passed 8,000 citations. The average number of citations per paper is 14.0, which is not bad when you consider that over half the papers were published under a year ago…
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In the Dark 