Archive for The Open Journal of Astrophysics

Weekly Update from the Open Journal of Astrophysics – 27/12/2025

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , , , , , , , on December 27, 2025 by telescoper

I wasn’t planning to do another update this week but I thought it would be best to complete the publications for 2025  at the Open Journal of Astrophysics, so that I don’t have to do a bigger update in the new year, and I have a bit of time this morning, so here we go.

Since the last update we have published four papers which brings the number in Volume 8 (2025) up to 201. Adding the 12 papers in the Supplement, this brings the final total for the year up to 213, and the total so far published by OJAp up to 448. In 2023 we published just 50 papers, so we have more than quadrupled in two years.

The first paper this week is “Transverse Velocities in Real-Time Cosmology: Position Drift in Relativistic N-Body Simulations” by Alexander Oestreicher (University of Southern Denmark), Chris Clarkson (QMUL, UK), Julian Adamek (Universität Zürich, CH) and Sofie Marie Koksbang (U. Southern Denmark). This study uses a general relativistic N-body simulation code to explore how cosmological structures affect position drift measurements, a new method for studying cosmic structure formation and velocity fields. This was published on Tuesday 23rd December 2025 in the folder Cosmology and Nongalactic Astrophysics.

The overlay is here:

 

You can find the officially accepted version on arXiv here and this is the announcement on Mastodon (Fediscience):

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Transverse Velocities in Real-Time Cosmology: Position Drift in Relativistic N-Body Simulations" by Alexander Oestreicher (University of Southern Denmark), Chris Clarkson (QMUL, UK), Julian Adamek (Universität Zürich, CH) and Sofie Marie Koksbang (U. Southern Denmark)

doi.org/10.33232/001c.154744

December 23, 2025, 9:33 am 1 boosts 0 favorites

 

The second paper of the week is “On the statistical convergence of N-body simulations of the Solar System” by Hanno Rein, Garett Brown and Mei Kanda (U. Toronto, Canada). This study presents numerical experiments to determine the minimum timestep for long-term simulations of the Solar System, finding that timesteps up to 32 days yield physical results.  It was published on Tuesday December 23rd in the folder Earth and Planetary Astrophysics.

The overlay is here:

 

You can find the official version of this one on arXiv here. The federated announcement on Mastodon is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "On the statistical convergence of N-body simulations of the Solar System" by Hanno Rein, Garett Brown and Mei Kanda (U. Toronto, Canada)

doi.org/10.33232/001c.154745

December 23, 2025, 9:50 am 6 boosts 9 favorites

Next, published on 24th December 2025 in the folder High-Energy Astrophysical Phenomena, we have “The explosion jets of the core-collapse supernova remnant Circinus X-1” by Noam Soker and Muhammad Akashi (Technion, Haifa, Israel). This paper suggests that the rings in the Circinus X-1 supernova remnant resulted from jet-driven explosions, supporting the jittering-jets explosion mechanism theory for core collapse supernovae.

The overlay is here:

The officially accepted paper can be found on arXiv here and the announcement on Mastodon is here

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "The explosion jets of the core-collapse supernova remnant Circinus X-1" by Noam Soker and Muhammad Akashi (Technion, Haifa, Israel)

doi.org/10.33232/001c.154770

December 24, 2025, 9:15 am 2 boosts 1 favorites

Finally for 2025 we have “Quantifying the Fermi paradox via passive SETI: a general framework” by Matthew Civiletti (City University of New York, USA). This was published on Wednesday 24th December in the folder Instrumentation and Methods for Astrophysics. The author uses SETI observations and the Drake Equation to calculate the probability of detecting at least one extraterrestrial signal, highlighting the model’s limitations and potential improvements. The overlay is here:

The officially accepted version can be found on arXiv here and the Mastodon announcement here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Quantifying the Fermi paradox via passive SETI: a general framework" by Matthew Civiletti (City University of New York, USA)

doi.org/10.33232/001c.154771

December 24, 2025, 9:27 am 1 boosts 1 favorites

And that concludes the updates for 2025. I’ll be back in a week with the first update of 2026, which will include the first paper(s) of Volume 9.

I’d like to thank everyone who has supported the Open Journal of Astrophysics this year – Editors, Reviewers, Authors and the excellent Library staff at Maynooth – and who have made it such a bumper year. In 2023 we published just 50 papers, so we have more than quadrupled in two years. How many will we publish in 2026?

Weekly Update from the Open Journal of Astrophysics – 20/12/2025

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , , , on December 20, 2025 by telescoper

Christmas is coming, but it’s still time for the usual update of the week’s new papers at the Open Journal of Astrophysics. Since the last update we have published two more regular papers, described below, which brings the number in Volume 8 (2025) up to 197, as well as the 12 papers in yesterday’s Supplement, and the total published for the year up to 209, and the total so far published by OJAp up to 444.

Please note that we will be pausing publishing activity from 24th December 2025 until Monday 5th January 2026. Submissions will remain open, but no more papers will be published in Volume 8 (2025) after Christmas Eve. We will resume in the New Year with Volume 9.

Now for this week’s update. Since I blogged about the contents of the Supplement yesterday I won’t repeat them here and will instead just include the two regular papers.

The first regular paper this week is “Optimal intrinsic alignment estimators in the presence of redshift-space distortions” by Claire Lamman (Harvard-Smithsonian CfA, USA), Jonathan Blazek (Ohio State U., USA) and Daniel J. Eisenstein (Northeastern U., USA). This was published on Monday December 15th 2025 in the folder  Cosmology and Nongalactic Astrophysics. The authors present estimators for quantifying intrinsic alignments in large spectroscopic surveys intended to inprove the constraints they provide for weak gravitational lensing and other cosmological applications.

The overlay is here:

You can find the officially accepted version on arXiv here and this is the announcement on Mastodon (Fediscience):

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Optimal intrinsic alignment estimators in the presence of redshift-space distortions" by Claire Lamman (Harvard-Smithsonian CfA), Jonathan Blazek (Ohio State U.) and Daniel J. Eisenstein (Northeastern U.); all based in the USA

doi.org/10.33232/001c.154373

December 15, 2025, 8:57 am 1 boosts 0 favorites

The second regular paper of the week is “What is the contribution of gravitational infall on the mass assembly of star-forming clouds? A case study in a numerical simulation of the interstellar medium” by Noé Brucy (Universite Claude Bernard Lyon 1, France), Enrique Vázquez-Semadeni (Universidad Nacional Autónoma de México, Mexico), Tine Colman (Universite Claude Bernard Lyon 1, France), Jérémy Fensch (Universite Claude Bernard Lyon 1, France) and Ralf S. Klessen (Universität Heidelberg, Germany). This was published in the folder Astrophysics of Galaxies on Friday 19th December 2025. This paper describes research using numerical simulations to quantify how much of the mass inflow into a star-forming cloud is driven by the self-gravity of the gas and the gravity from the stellar disk.

The overlay is here:

You can find the official version of this one on arXiv here. The federated announcement on Mastodon is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "What is the contribution of gravitational infall on the mass assembly of star-forming clouds? A case study in a numerical simulation of the interstellar medium" by Noé Brucy (Universite Claude Bernard Lyon 1, France), Enrique Vázquez-Semadeni (Universidad Nacional Autónoma de México, Mexico), Tine Colman (Lyon), Jérémy Fensch (Lyon) and Ralf S. Klessen (Universität Heidelberg, Germany)

doi.org/10.33232/001c.154637

December 19, 2025, 8:30 am 0 boosts 0 favorites

And that concludes the update for this week, which will be the last Saturday update for 2025.

Supplement to the Open Journal of Astrophysics – “Pulsar Science with the SKAO”

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , on December 19, 2025 by telescoper

It’s been a busy day at the Open Journal of Astrophysics as we’ve published 12 related papers in the form of our first ever Supplement; officially it is Vol. 8 Supplement Issue 1. The idea of a Supplement is to publish a set of related papers together. I imagine it might be of interest for publishing conference proceedings, etc.

The topic of this Supplement is Pulsar Science with the Square Kilometre Array Observatory and it includes updates to the Science Case for the SKAO, the previous version of which is 10 years old. All the papers are indendependently peer-reviewed, which took some organizing and a lot of time because many potential referees are themselves members of the SKA Pulsar Science Working Group! Anyway, the final versions of all the papers hit the arXiv this morning so I published them all today.

Rather than include all 12 papers in tomorrow’s Saturday update I decided just to show the overlay for the overview of the special issue, which is here:

The following paragraph describes the content of the supplement and includes links to the other 11 papers in the issue.

The large instantaneous sensitivity, a wide frequency coverage and flexible observation modes with large number of beams in the sky are the main features of the upcoming SKA observatory’s two telescopes, the SKA-Low and the SKA-Mid, which are located on two different continents. Owing to these capabilities, the SKAO telescopes are going to be a game-changer for radio astronomy in general and pulsar astronomy in particular. The eleven articles in this special issue on pulsar science with the SKA Observatory describe its impact on different areas of pulsar science. Phase 1 of the rollout of the SKAO telescope is likely to double the known pulsar population in new surveys described in the first three papers (Keane et al. 2025Abbate et al. 2025Bagchi et al. 2025). These new discoveries will improve our understanding of the dynamics, evolution and gas content of globular clusters and the black hole at the centre of the Milky Way galaxy apart from increasing the samples for each of different kinds of radio emitting neutron stars (Levin et al. 2025). The larger population sample will enhance our understanding of the magneto-ionic interstellar medium (Tiburzi et al. 2025Xu et al. 2025), the pulsar magnetosphere (Oswald et al. 2025) and pulsar wind nebulae (Gelfand et al. 2025). Moreover, the discovery of exotic neutron star systems will test gravity theory ever more stringently (Krishnan et al. 2025) and will probe fundamental physics at sub-atomic level (Basu et al. 2025). Finally, this enhanced sample is likely to make the sky portrait sharper in nano-Hertz gravitational waves impacting on our understanding of the Universe in a fundamental way (Shannon et al. 2025). In summary, the papers in this special issue describe the way the upcoming SKA Observatory’s telescopes address fundamental physics through the study of pulsars and gravitational waves.

Weekly Update from the Open Journal of Astrophysics – 13/12/2025

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , , , , , , , , , , , , , , on December 13, 2025 by telescoper

It’s time once again for the usual Saturday morning update of the week’s new papers at the Open Journal of Astrophysics. Since the last update we have published a further five papers, which brings the number in Volume 8 (2025) up to 195, and the total so far published by OJAp up to 430.

The first paper this week is “Cosmic Rays Masquerading as Cool Cores: An Inverse-Compton Origin for Cool Core Cluster Emission” by Philip F. Hopkins (Caltech), Eliot Quataert (Princeton), Emily M. Silich, Jack Sayers, Sam B. Ponnada and Isabel S. Sands (Caltech).  This was published on Tuesday 9th December 2025 in the folder marked High-Energy Astrophysical Phenomena. It presents an argument  that cosmic-ray inverse-compton emission could contribute significantly to the X-ray surface brightness (SB) in cool-corre clusters, implying that gas densities may have been overestimated therein.

The overlay is here:

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

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Cosmic Rays Masquerading as Cool Cores: An Inverse-Compton Origin for Cool Core Cluster Emission" by

Philip F. Hopkins (Caltech), Eliot Quataert (Princeton), Emily M. Silich, Jack Sayers, Sam B. Ponnada and Isabel S. Sands (Caltech)

doi.org/10.33232/001c.154053

December 9, 2025, 7:22 am 1 boosts 0 favorites

The second paper of the week is “Detecting False Positives With Derived Planetary Parameters: Experimenting with the KEPLER Dataset” by Ayan Bin Rafaih (Aitchison College, Lahore, Pakistan) and Zachary Murray (Université Côte d’Azur, France). This one was published on 9th December 2025 in the folder Earth and Planetary Astrophysics. It is an investigation into the performance of a range of machine-learning algorithms on the KEPLER dataset, using precision-recall trade-off and accuracy metrics.

The overlay is here:

You can find the official version of this one on arXiv here. The federated announcement on Mastodon is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Detecting False Positives With Derived Planetary Parameters: Experimenting with the KEPLER Dataset" by Ayan Bin Rafaih (Aitchison College, Lahore, Pakistan) and Zachary Murray (Université Côte d’Azur, France)

doi.org/10.33232/001c.154054

December 9, 2025, 7:34 am 1 boosts 0 favorites

Next one up is “The role of peculiar velocity uncertainties in standard siren cosmology” by Chris Blake and Ryan J. Turner (Swinburne, Australia). This paper discusses the impact of peculiar velocities on the error in H0 determinations from local distance indicators with observed redshifts, incorporating the effect of bulk flows. It was published on Tuesday 9th December in the folder Cosmology and Nongalactic Astrophysics.

The overlay is here:

You can find the official accepted version on arXiv here. The fediverse announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "The role of peculiar velocity uncertainties in standard siren cosmology" by Chris Blake and Ryan J. Turner (Swinburne, Australia)

doi.org/10.33232/001c.154055

December 9, 2025, 7:47 am 1 boosts 0 favorites

The fourth article of the week is “Transient QPOs of Fermi-LAT blazars with Linearly Multiplicative Oscillations” by P. Penil (Clemson University, USA) and 7 others based in the USA, Italy and Germany. This was published on Thursday 10th December in the folder High-Energy Astrophysical Phenomena. This paper presents an investigation of patterns of quasi-periodic oscillations in observed blazar systems characterized by periodic multiplicative amplitudes including both the periodicities and long-term variations.  The overlay is here:

You can find the official published version on arXiv here. The Fediverse announcement follows:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Transient QPOs of Fermi-LAT blazars with Linearly Multiplicative Oscillations" by P. Penil (Clemson University, USA) and 7 others based in the USA, Italy and Germany

doi.org/10.33232/001c.154123

December 10, 2025, 12:22 pm 0 boosts 1 favorites

The last paper for this week is “Tidally Delayed Spin-Down of Very Low Mass Stars” by Ketevan Kotorashvili and Eric G. Blackman (U. Rochester, USA). This was published on Friday 12th December (yesterday) in the folder Solar and Stellar Astrophysics. It discusses the effect of tides from sub-stellar companions on rotational evolution of very low-mass stars, suggesting that these may explain the dearth of field, late-type M dwarfs with intermediate rotation periods.

The overlay is here:

 

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

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Tidally Delayed Spin-Down of Very Low Mass Stars" by Ketevan Kotorashvili and Eric G. Blackman (U. Rochester, USA)

doi.org/10.33232/001c.154268

December 12, 2025, 10:31 am 1 boosts 0 favorites

 

And that concludes the update for this week. I will do another of these regular announcements next Saturday, which will be the last such update for 2025. Will we make it past 200 for the year? Tune in next week to find out!

Weekly Update from the Open Journal of Astrophysics – 06/12/2025

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , , , , , , , , , , , , , , , on December 6, 2025 by telescoper

Once again it’s time for the usual Saturday morning update of the week’s new papers at the Open Journal of Astrophysics. Since the last update we have published a further six papers, which brings the number in Volume 8 (2025) up to 190, and the total so far published by OJAp up to 425. I blogged about the significance of the latter figure here.

The first paper this week is “The galaxy-IGM connection in THESAN: observability and information content of the galaxy-Lyman-alpha cross-correlation at z>6” by Enrico Garaldi (U. Tokyo, Japan), Verena Bellscheidt (Tech. U. Munich, Germany), Aaron Smith (U. Texas Austin, USA) and Rahul Kannan (York U. Canada). This paper was published on Monday 1st December 2025 in the folder Cosmology and Nongalactic Astrophysics. It describes an investigation of the impact of observational limitations on the ability to retrieve the intrinsic galaxy-Lyman-alpha cross correlation from line-of-sight observations.

The overlay is here:

 

 

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

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "The galaxy-IGM connection in THESAN: observability and information content of the galaxy-Lyman-alpha cross-correlation at z>6" by Enrico Garaldi (U. Tokyo, Japan), Verena Bellscheidt (Tech. U. Munich, Germany), Aaron Smith (U. Texas Austin, USA) and Rahul Kannan (York U. Canada)

doi.org/10.33232/001c.151666

December 1, 2025, 8:37 am 1 boosts 0 favorites

The second paper of the week is “A Less Terrifying Universe? Mundanity as an Explanation for the Fermi Paradox” by Robin H.D. Corbet (U. Maryland, USA). This paper was published on 1st December 2025 in the folder Instrumentation and Methods for Astrophysics. It presents a discussion of possible explanations for the lack of s evidence for the presence of technology-using extraterrestrial civilizations in the Galaxy (usually called the Fermi paradox). The overlay is here:

 

 

You can find the official version of this one on arXiv here. The federated announcement on Mastodon is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "A Less Terrifying Universe? Mundanity as an Explanation for the Fermi Paradox" by Robin H.D. Corbet (U. Maryland, USA)

doi.org/10.33232/001c.151454

December 1, 2025, 8:50 am 2 boosts 2 favorites

 

Next one up is “Sulphur abundances in star-forming regions from optical emission lines: A new approach based on photoionization models consistent with the direct method” by Enrique Pérez-Montero, Borja Pérez-Díaz, & José M. Vílchez ( (Instituto de Astrofísica de Andalucía, Spain), Igor A. Zinchenko (LMU, Germany), Asier Castrillo, Marta Gavilán, Sandra Zamora & Ángeles I. Díaz (Universidad Autonoma de Madrid, Spain). This was published on 1st December 2025 in the folder Astrophysics of Galaxies. This study uses the emission lines produced in the optical part of the spectrum and with photoionization models to derive sulphur chemical abundances in the gas-phase of star-forming galaxies.

The overlay is here:

 

 

You can find the official accepted version on arXiv here. The fediverse announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Sulphur abundances in star-forming regions from optical emission lines: A new approach based on photoionization models consistent with the direct method" by Enrique Pérez-Montero, Borja Pérez-Díaz, & José M. Vílchez ( (Instituto de Astrofísica de Andalucía, Spain), Igor A. Zinchenko (LMU, Germany), Asier Castrillo, Marta Gavilán, Sandra Zamora & Ángeles I. Díaz (Universidad Autonoma de Madrid , Spain)

doi.org/10.33232/001c.151253

December 1, 2025, 9:12 am 0 boosts 0 favorites

The fourth article of the week is “Bayesian Posteriors with Stellar Population Synthesis on GPUs” by Georgios Zacharegkas & Andrew Hearin (Argonne National Laboratory, USA) and Andrew Benson (Carnegie Observatories, USA). This is an exploration of a range of computational techniques aimed at accelerating Stellar Population Synthesis predictions of galaxy photometry using the JAX library to target GPUs (Graphics Processing Units, in case you didn’t know). This paper was published on Tuesday December 2nd 2025 in the folder Astrophysics of Galaxies.

The overlay is here:

 

You can find the official published version on arXiv here. The Fediverse announcement follows:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Bayesian Posteriors with Stellar Population Synthesis on GPUs" by Georgios Zacharegkas & Andrew Hearin (Argonne National Laboratory, USA) and Andrew Benson (Carnegie Observatories, USA)

doi.org/10.33232/001c.151255

December 2, 2025, 7:38 am 3 boosts 1 favorites

Next one up is “IAEmu: Learning Galaxy Intrinsic Alignment Correlations” by Sneh Pandya Yuanyuan Yang, Nicholas Van Alfen, Jonathan Blazek and Robin Walters (Northeastern University, Boston, USA). This presents a neural-network-based emulator that predicts the galaxy position-position, position-orientation, and orientation-orientation, correlation functions and their uncertainties using mock catalogs based on the halo occupation distribution (HOD) framework. It was published on December 2nd 2025 in the folder Cosmology and Nongalactic Astrophysics. The overlay is here:

The official accepted version can be found on arXiv here. The Mastodon announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "IAEmu: Learning Galaxy Intrinsic Alignment Correlations" by Sneh Pandya Yuanyuan Yang, Nicholas Van Alfen, Jonathan Blazek and Robin Walters (Northeastern University, Boston, USA)

doi.org/10.33232/001c.151749

December 2, 2025, 7:52 am 1 boosts 0 favorites

The last paper for this weel is “Unraveling the Nature of the Nuclear Transient AT2020adpi” by Paarmita Pandey (Ohio State University, USA) and a team of 15 others based in the USA, UK and Australia. This was published on Thursday December 4th 2025 in the folder High-Energy Astrophysical Phenomena. It is an investigation into a particular transient event AT2020adpi and a discussion of whether it is an extreme example of AGN variability or a Tidal Disruption Event (TDE). The overlay is here:

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

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Unraveling the Nature of the Nuclear Transient AT2020adpi" by Paarmita Pandey (Ohio State University, USA) and 15 others based in the USA, UK and Australia

doi.org/10.33232/001c.151453

December 4, 2025, 8:48 am 1 boosts 0 favorites

And that concludes the update for this week. I will do another next Saturday.

Like a Million Pounds…

Posted in Biographical, Open Access with tags , , , , , , , on December 4, 2025 by telescoper

I’ve come down with some sort of lurgy and had to cancel a tutorial that was due to take place today, which I am sorry about. I did, however, manage to rise from my sick bed earlier this morning to publish a paper at the Open Journal of Astrophysics. When I checked the publishing dashboard I saw that this one is paper No. 425. This is a significant figure if you reckon by the cost of an Article Processing Charge (APC) at Monthly Notices of the Royal Astronomical Society. The current APC is £2356 per paper. If you multiply this by 425 the result is just over a million pounds (£1,001,300 to be exact). The Open Journal of Astrophysics, being a Diamond Open Access journal, is totally free for authors.

I mentioned a couple of weeks ago, that this is a small fraction of the money being wasted by the astronomical community worldwide on publication charges but if even a small operation like ours can save a million pounds, just think of what could happen if we all published this way! For one thing, there would certainly be more money available for actual research. That doesn’t only go for astronomy, of course: almost every scientific discipline is being ripped off by publishers who have hijacked the Open Access movement to generate income from APCs.

I’ll repeat the quotation I posted yesterday about a scandal relating to corporate publishing giant Elsevier

The scandal exposes the windfall profits of scientific publishers, who in recent years have amassed billions of dollars in earnings from public funds earmarked for science.

It’s a shocking idea, I know, but what if we spent public funds on what they are supposed to be spent on rather than handing millions to greedy publishers?

Eight Years in Maynooth…

Posted in Artificial Intelligence, Biographical, Education, Maynooth with tags , , on December 1, 2025 by telescoper
Maynooth University Library, home of the famous cat

Today is 1st December 2025, which means that it’s eight years to the day since I started work at Maynooth University. Despite the frustrations, I’m still very happy I made the move all that time ago.

We’ve now had more than a year since the merger of the former Departments of Theoretical and Experimental Physics. This has gone pretty well, actually, with significant improvements in terms of some steps forward in rationalising teaching. It does, however, feel less like a merger and more like an acquisition, with the theoretical activity effectively subsumed into the old Experimental Physics department. I suppose that was inevitable given the relative sizes of the two former Departments, but it has led to a loss of identity and the loss of the group spirit we use to have in Theoretical Physics. To add to this a number of familiar faces have left – two of my own PhD students, Aonghus Hunter-McCabe and Aoibhinn Gallagher have graduated and left, as have others with different supervisors. I am delighted for their success, of course, but will miss having them around.

I continue to enjoy teaching, and was pleasantly surprised to continue doing the same modules this academic year as last. The big change in that regard has been the adoption of different assessment methods to deal with the possibility of students using AI to do their coursework. That seems to be going reasonably well, though I’ll have to wait until the January examinations to see the outcomes.

The thing I’m probably most proud of over the past eight years is, with the huge help of staff at Maynooth University Library, getting the Open Journal of Astrophysics off the ground and attracting some excellent papers. This year has seen yet more significant growth, publications this year set to reach 200, after 120 in 2024 and just 50 the year before that (2024). We’re still smaller than many of the mainstream astrophysics journals, but we’re still growing…

Anyway, eight years of service mean that only two remain until I can claim the full state pension. I’ll be retiring as soon as I can afford to. There were Open Days at Maynooth on Friday and Saturday (28th and 29th November, respectively). These were for prospective students to enter in September 2026. Since I don’t teach any first or second year Physics modules now, and that is likely to continue, it looks like I’ll never see any of that intake in class.

Weekly Update from the Open Journal of Astrophysics – 29/11/2025

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , , , , , , , , on November 29, 2025 by telescoper

It’s Saturday again, so it’s time for the usual update of the week’s new papers at the Open Journal of Astrophysics. Publishing this week was interrupted by the Thanksgiving holiday in the United States, which meant there were no arXiv announcements yesterday. Nevertheless, since the last update we have published another four papers, which brings the number in Volume 8 (2025) up to 184, and the total so far published by OJAp up to 419.

The first paper this week is “A theoretical prediction for the dipole in nearby distances using cosmography” by Hayley J. Macpherson (U. Chicago, USA) and Asta Heinesen (Niels Bohr Institute, Denmark). This was published on Monday 24th November 2025 in the folder Cosmology and Nongalactic Astrophysics. It presents a method to predict the dipole in luminosity distances that arises due to nearby inhomogeneities to leading-order correction to the standard isotropic distance-redshift law. Incidentally, I wrote about a talk by one of the authors here.

The overlay is here:

 

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

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "A theoretical prediction for the dipole in nearby distances using cosmography" by Hayley J Macpherson (U. Chicago, USA) and Asta Heinesen (Niels Bohr Institute, Denmark)

doi.org/10.33232/001c.150319

November 24, 2025, 8:25 am 2 boosts 1 favorites

 

The second paper of the week is “A Targeted Gamma-Ray Search of Five Prominent Galaxy Merger Systems with 17 years of Fermi-LAT Data” by Siddhant Manna and Shantanu Desai (IIT Hyderabad Kandi, India). This one was published on Tuesday November 25th 2025 in the folder marked High-Energy Astrophysical Phenomena. It describes a search for gamma-ray emission in Fermi-LAT data from five merging galaxy systems with marginal detections for two of them

The overlay is here:

 

You can find the official version of this one on arXiv here. The federated announcement on Mastodon is here:

 

Next one up is “Metallicity fluctuation statistics in the interstellar medium and young stars – II. Elemental cross-correlations and the structure of chemical abundance space” by Mark R. Krumholz (ANU, Australia), Yuan-Sen Ting (Ohio State U., USA), Zefeng Li (Durham U., UK), Chuhan Zhang (ANU), Jennifer Mead (Columbia U., USA) and Melissa K. Ness (ANU). This was published in the folder Astrophysics of Galaxies on Wednesday November 26th. It presents an extended stochastically-forced diffusion model for the chemical evolution of galaxies, making quantitative predictions for the degree of correlation in abundance patterns in both gas and young stars.

The overlay is here:

 

You can find the official accepted version on arXiv here. The fediverse announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Metallicity fluctuation statistics in the interstellar medium and young stars – II. Elemental cross-correlations and the structure of chemical abundance space" by Mark R. Krumholz (ANU, Australia), Yuan-Sen Ting (Ohio State U., USA), Zefeng Li (Durham U., UK), Chuhan Zhang (ANU), Jennifer Mead (Columbia U., USA) and Melissa K. Ness (ANU)

doi.org/10.33232/001c.150356

November 26, 2025, 8:34 am 1 boosts 1 favorites

The fourth and final paper of the week is “Simulating realistic Lyman-alpha emitting galaxies including the effect of radiative transfer” by Hasti Khoraminezhad & Shun Saito (Missouri Institute of Science & Technology, USA), Max Gronke (U. Heidelberg, Germany) and Chris Byrohl (MPA Garching, Germany). An empirical model for Lyman-alpha emitters (LAEs) which provides predictions for the halo occupation distributions and relationship between luminosity and halo mass, including the distribution of satellite LAEs. It was published on Thursday November 27th 2025 in the folder Astrophysics of Galaxies.

The overlay is here:

You can find the official published version on arXiv here. The Fediverse announcement follows:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Simulating realistic Lyman-alpha emitting galaxies including the effect of radiative transfer" by Hasti Khoraminezhad & Shun Saito (Missouri Institute of Science & Technology, USA), Max Gronke (U. Heidelberg, Germany) and Chris Byrohl (MPA Garching, Germany)

doi.org/10.33232/001c.151254

November 27, 2025, 9:20 am 1 boosts 1 favorites

And that concludes the update for this week. I will do another next Saturday.

Weekly Update from the Open Journal of Astrophysics – 22/11/2025

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , , , , , , , , , on November 22, 2025 by telescoper

It’s Saturday again, so it’s time for the usual update of the week’s new papers at the Open Journal of Astrophysics. Since the last update we have published another five papers, which brings the number in Volume 8 (2025) up to 180, and the total so far published by OJAp up to 415.

The first paper to report this week is “Probing Anisotropic Cosmic Birefringence with Foreground-Marginalised SPT B-mode Likelihoods” by Lennart Balkenhol (Sorbonne Université, France), A. Coerver (UC Berkeley, USA), C. L. Reichardt (U. Melbourne, Australia) and J. A. Zebrowski (U. Chicago, USA). This paper was published on Monday November 17th in the folder Cosmology and Nongalactic Astrophysics. It presents a way of using data from the Souh Pole Telescope (SPT) in the CMB-lite framework to constrain the level of cosmic birefringence.  The overlay is here:

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

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Probing Anisotropic Cosmic Birefringence with Foreground-Marginalised SPT B-mode Likelihoods" by Lennart Balkenhol (Sorbonne Université, France), A. Coerver (UC Berkeley, USA), C. L. Reichardt (U. Melbourne, Australia) and J. A. Zebrowski (U. Chicago, USA)

doi.org/10.33232/001c.147459

November 17, 2025, 8:43 am 1 boosts 0 favorites

The second paper of the week is “Radio Observations of a Candidate Redback Millisecond Pulsar: 1FGL J0523.5-2529” by Owen. A. Johnson & E. F. Keane (Trinity College Dublin, Ireland), D. J. McKenna (ASTRON, NL), H. Qiu (SKAO, UK), S. J. Swihart (Insitute for Defense Analyses, USA), J. Strader (Michigan State U., USA) and M. McLaughlin (West Virginia U., USA). This one was published on Tuesday November 18th 2025 in the folder marked High-Energy Astrophysical Phenomena and it describes a search for radio emission from a candidate “redback pulsar” J0523.5-2529 resulting in upper limits but no detection.

The overlay is here:

You can find the official version of this one on arXiv here. The federated announcement on Mastodon is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Radio Observations of a Candidate Redback Millisecond Pulsar: 1FGL J0523.5-2529" by Owen. A. Johnson & E. F. Keane (Trinity College Dublin, Ireland), D. J. McKenna (ASTRON, NL), H. Qiu (SKAO, UK), S. J. Swihart (Insitute for Defense Analyses, USA), J. Strader (Michigan State U., USA) and M. McLaughlin (West Virginia U., USA)

doi.org/10.33232/001c.147516

November 18, 2025, 8:42 am 1 boosts 0 favorites

Next one up is “The role of turbulence in setting the phase of the ISM and implications for the star formation rate” by Tine Colman (Université Paris-Saclay, France) and 13 others based in France, Germany, Italy and the UK. This was published in the folder Astrophysics of Galaxies on Tuesday November 18th. It descrtibes using a suite of stratified box simulations to explore the link between star formation, turbulence and the thermal state of the multi-phase interstellar medium (ISM).

The overlay is here:

You can find the official accepted version on arXiv here. The fediverse announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "The role of turbulence in setting the phase of the ISM and implications for the star formation rate" by Tine Colman (Université Paris-Saclay, France) and 13 others based in France, Germany, Italy and the UK.

doi.org/10.33232/001c.147517

November 19, 2025, 8:19 am 0 boosts 0 favorites

The fourth paper of the week is “A Bimodal Metallicity Distribution Function in the Ultra-Faint Dwarf Galaxy Reticulum II” by Alice M. Luna (U. Chicago, USA) and 8 others based in the USA, Korea and Canada. This was published on Wednesday November 19th in the folder Astrophysics of Galaxies. It decribes low-resolution Magellan/IMACS spectroscopy of 167 stars in the ultra-faint galaxy Reticulum II, revealing a clearly bimodal distribution.

The overlay is here:

You can find the official published version on arXiv here. The Fediverse announcement follows:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "A Bimodal Metallicity Distribution Function in the Ultra-Faint Dwarf Galaxy Reticulum II" by Alice M. Luna (U. Chicago, USA) and 8 others based in the USA, Korea and Canada.

doi.org/10.33232/001c.147696

November 19, 2025, 8:37 am 0 boosts 0 favorites

The fifth and final paper for this week is “Cool Gas in the Circumgalactic Medium of Massive Post Starburst Galaxies” by Zoe Harvey, Sahyadri Krishna, Vivienne Wild & Rita Tojeiro (U. St Andrews, UK) and Paul Hewett (U. Cambridge, UK). This was published on Thursday November 20th in the folder Astrophysics of Galaxies.

The overlay is here:

The officially accepted version can be found on arXiv here. The Fediverse announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Cool Gas in the Circumgalactic Medium of Massive Post Starburst Galaxies" by Zoe Harvey, Sahyadri Krishna, Vivienne Wild & Rita Tojeiro (U. St Andrews, UK) and Paul Hewett (U. Cambridge, UK)

doi.org/10.33232/001c.147836

November 20, 2025, 9:02 am 1 boosts 0 favorites

And that concludes the update for this week. I will do another next Saturday.

Visiting Speaker

Posted in Maynooth, OJAp Papers, Open Access, The Universe and Stuff with tags , , on November 21, 2025 by telescoper

I’ve been playing host today to my former PhD student, now at the University of Vienna, Mateja Gosenca, who gave a talk on “Ultralight Dark Matter: Phenomenology and Observational Constraints”. Mateja did an MSc at the University of Sussex before doing a PhD under my supervision, so it is very nice to have her visit us in Maynooth.

It was only when I started to think about how to introduce her Colloquium that I remembered that Mateja was co-author of the very first paper published by the Open Journal of Astrophysics, way back in 2016. At that time we were running an experimental prototype site before switching to the Scholastica platform we now use, but it was still a landmark. We’ve now published 415 papers.

Update: Obligatory pub photograph