I thought I’d pass on a little amusement arising from last week’s Eclipse Event in Maynooth. I gave a very short and non-technical talk about the famous 1919 Eclipse Expeditions which I have mentioned many times on this blog. As you probably know there were two expeditions, one to Sobral in Brazil and the other to the island of Principe, off the coast of Equatorial Guinea. Here’s a nice and very informative old graphic (from the London Illustrated News) about the expeditions, showing the two locations:
I finished my talk and had one or two questions but we had to move on to the next speaker, who happened to be giving the last talk of the day.
After the session finished I was packing up some things to take back to the office before heading to the pub when a little boy came up to me and asked: “So which expedition were you on, the one to Brazil or the one to Africa?”
Although it’s still holiday season for some, 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 four papers, bringing the number in Volume 9 (2026) to 171 and the total so far published by OJAp up to 619.
I continue to include the posts made on our Mastodon account (on Fediscience); these announcements also show the DOI for each paper.
New Publication at the Open Journal of Astrophysics: "Search for neutrino emission from blazar γ-ray flares accounting for possible neutrino time delays" by Egor Podlesny & Foteini Oikonomou (Norwegian University of Science & Technology, Trondheim, Norway)
The second paper for this week, published on Tuesday 11th August in the folder Cosmology and Nongalactic Astrophysics is “The velocity coherence scale: a novel probe of cosmic homogeneity and a potential standard ruler” by Leonardo Giani (Swinburne University of Technology), Cullan Howlet (U. Queensland), Chris Blake (Swinburne), Ryan J. Turner (Australia National University) and Tamara M. Davis (U. Queensland) – all in Australia. This paper argues that velocity coherence scale, a measure that identifies the transition point of galaxy motion from correlated to anti-correlated, could potentially characterize the onset of cosmic homogeneity.
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: "The velocity coherence scale: a novel probe of cosmic homogeneity and a potential standard ruler" by Leonardo Giani (Swinburne U. Tech.), Cullan Howlet (U. Queensland), Chris Blake (Swinburne), Ryan J. Turner (ANU) and Tamara M. Davis (U. Queensland) – all in Australia.
New Publication at the Open Journal of Astrophysics: "A GLIMPSE of the 99%: a census of the faintest galaxies during the epoch of reionization and its implications for galaxy formation models" by Hakim Atek (Sorbonne Université, Paris, France) and 21 others based around the world.
The fourth and final paper of the week was published on Wednesday 12th August in the folder Astrophysics of Galaxies: “Dust and Grain Size Evolution in Galaxy Simulations: What Matters and What Does Not” by Massimiliano Parente & Desika Narayanan (U. Florida, USA) and Paul Torrey (U. Virginia, USA) presents the first implementation of an evolving dust grain size distribution within a model of galaxy evolution, successfully reproducing key observational constraints and exploring the mechanisms shaping galaxies.
The overlay is here:
The officially-accepted version of the paper can be found on arXiv here and the Fediverse announcement here:
New Publication at the Open Journal of Astrophysics: "Dust and Grain Size Evolution in Galaxy Simulations: What Matters and What Does Not" by Massimiliano Parente & Desika Narayanan (U. Florida, USA) and Paul Torrey (U. Virginia, USA)
That’s all for this week. We’re just ticking over at the moment, and steadily building up a backlog of papers to publish while we wait for authors to put their final versions on arXiv. I have a feeling there’s going to be a big splurge sometime. Will it be next week? We’ll find out next Saturday!
Although it’s holiday season for some, 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 four papers, bringing the number in Volume 9 (2026) to 167 and the total so far published by OJAp up to 615.
I continue to include the posts made on our Mastodon account (on Fediscience); these announcements also show the DOI for each paper.
New Publication at the Open Journal of Astrophysics: "Small-scale turbulence alongside large-scale turbulence in a z=1.87 star-forming galaxy with an outflowing wind, revealed by multi-point structure functions" by Itzhak Goldman (Afeka College, Israel)
The second paper for this week, published on Thursday 6th August in the folder Astrophysics of Galaxies, is “From Clumps to Sheets: Geometry Controls the Temperature PDF of Multi-Phase Gas” by Zirui Chen and S. Peng Oh (UC Santa Barbara, USA). This study uses 3D hydrodynamic simulations to show that the temperature probability distribution functions (PDFs) of multi-phase turbulent gas differ significantly under interstellar medium (ISM) and circumgalactic medium (CGM) conditions.
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: "From Clumps to Sheets: Geometry Controls the Temperature PDF of Multi-Phase Gas" by Zirui Chen and S. Peng Oh (UC Santa Barbara, USA)
New Publication at the Open Journal of Astrophysics: "First Detection of Extensive Air Showers Using a Small-Aperture Fluorescence Telescope" by M. Zotov (M.V. Lomonosov Moscow State University, Russia) and 7 others based in Russia and Armenia
The fourth and final paper of the week was published on Friday 7th August in the folder Cosmology and Nongalactic Astrophysics: “TDCOSMO XXVI: Uniform Lens Modeling of Eight Doubly Imaged Quasars“, by Ryan Brady (Stony Brook University, USA) and 9 others based all around the world, presents a new method for analyzing doubly imaged quasars using the Hubble Space Telescope, revealing that arc surface brightness is key to precision in mass model measurements.
The overlay is here:
The officially-accepted version of the paper can be found on arXiv here and the Fediverse announcement here:
New Publication at the Copen Journal of Astrophysics: "TDCOSMO XXVI: Uniform Lens Modeling of Eight Doubly Imaged Quasars" by Ryan Brady (Stony Brook University, USA) and 9 others based around the world.
That’s all for this week. We have about a dozen more papers accepted and waiting for the authors to put the final version on arXiv, which they will presumably do when they’re back from holiday. I’ll do an update next weekend and we’ll see!
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 three papers, bringing the number in Volume 9 (2026) to 163 and the total so far published by OJAp up to 611.
I 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 28th July in the folder Cosmology and Nongalactic Astrophysics. “The Origins of the Bulk Flow” by Richard Watkins & Trajan Clark (Willamett U., USA) and Hume A Feldman (U. Kansas, USA) analyzes the origin of large-scale bulk flow using the CosmicFlows-4 catalog, finding that it is largely influenced by structures beyond 200 h-1 Mpc, challenging previous assumptions.
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 Origins of the Bulk Flow" by Richard Watkins & Trajan Clark (Willamett U., USA) and Hume A Feldman (U. Kansas, USA).
The second paper for this week, also published on Tuesday 28th July in the folder Cosmology and Nongalactic Astrophysics is: “Enhancing weak lensing redshift distribution characterization by optimizing the Dark Energy Survey Self-Organizing Map Photo-z method” by A. Campos (Carnegie Mellon U., USA) and the DES collaboration (113 authors). This study improves the Self-Organizing Map methodology for estimating redshift distribution in galaxies, notably reducing overlap between redshift bins, in preparation for the Dark Energy Survey Year 6 data.Abstractfor Enhancing weak lensing redshift distribution characterization by optimizing the Dark Energy Survey Self-Organizing Map Photo-z method.
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: "Enhancing weak lensing redshift distribution characterization by optimizing the Dark Energy Survey Self-Organizing Map Photo-z method" by A. Campos (Carnegie Mellon U., USA) and the DES collaboration (113 authors)
New Publication at the Open Journal of Astrophysics: "The Ray Tracing Sampler: Bayesian Sampling of Neural Networks for Everyone" by Peter Behroozi (U. Arizona, USA)
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 🥰 🔭🧪
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 the Open Journal of Astrophysics. Since the last update we have published a further nine papers, bringing the number in Volume 9 (2026) 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] 88μm 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 (Université 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 (Université 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-α 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-α 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 (Université de Genève, 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 (Université de Genève, 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 Peña 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 α. 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 the Open Journal of Astrophysics. Since the last update we have published a further nine papers, bringing the number in Volume 9 (2026) 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 für 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!
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In the Dark 