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

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

@OJ_Astro@fediscience.org

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)

https://doi.org/10.33232/001c.154053

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

@OJ_Astro@fediscience.org

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)

https://doi.org/10.33232/001c.154054

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

@OJ_Astro@fediscience.org

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)

https://doi.org/10.33232/001c.154055

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

@OJ_Astro@fediscience.org

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

https://doi.org/10.33232/001c.154123

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

@OJ_Astro@fediscience.org

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)

https://doi.org/10.33232/001c.154268

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!

#arxiv241117916v3 #arxiv250713906v3 #arxiv250718712v2 #arxiv250813801v2 #arxiv250903101v2 #blazars #coolCoreClusters #cosmicRays #cosmologyAndNongalacticAstrophysics #diamondOpenAccess #diamondOpenAccessPublishing #earthAndPlanetaryAstrophysics #fermiLat #highEnergyAstrophysicalPhenomena #kepler #machineLearning #openAccess #openAccessPublishing #openJournalOfAstrophysics #peculiarMotions #quasiPeriodicOscillations #solarAndStellarAstrophysics #standardSirens #theOpenJournalOfAstrophysics #tidalSpinDown #transientAstronomy #veryLowMassStars

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

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

@OJ_Astro@fediscience.org

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)

https://doi.org/10.33232/001c.150319

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

@OJ_Astro@fediscience.org

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)

https://doi.org/10.33232/001c.150356

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

@OJ_Astro@fediscience.org

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)

https://doi.org/10.33232/001c.151254

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

#arxiv250701095v3 #arxiv250714572v2 #arxiv250716707v2 #arxiv250806232v2 #astrophysicsOfGalaxies #chemicalAbundances #cosmography #cosmology #cosmologyAndNongalacticAstrophysics #diamondOpenAccess #diamondOpenAccessPublishing #fermiLat #galaxyMergers #gammaRay #highEnergyAstrophysicalPhenomena #lymanAlphaEmitters #metallicity #openAccess #openAccessPublishing #openJournalOfAstrophysics #theOpenJournalOfAstrophysics

Dark Matter in the Centre of our Home Galaxy 
Fermi telescope made clean observation of excess γ-ray emission at the centre of our home galaxy which appeared non-spherical and flattened............
#CTAO #Darkenergy #darkmatter #Darkmatterparticle #DM #FermiLAT #Fermitelescope #GalacticCentreExcess #galaxy #GCE #homegalaxy #milkyway #WIMP
Umesh Prasad

https://www.scientificeuropean.co.uk/sciences/space/dark-matter-in-the-centre-of-our-home-galaxy/

Dark Matter in the Centre of our Home Galaxy 
Fermi telescope made clean observation of excess γ-ray emission at the centre of our home galaxy which appeared non-spherical and flattened............
#CTAO #Darkenergy #darkmatter #Darkmatterparticle #DM #FermiLAT #Fermitelescope #GalacticCentreExcess #galaxy #GCE #homegalaxy #milkyway #WIMP
Umesh Prasad

https://www.scientificeuropean.co.uk/sciences/space/dark-matter-in-the-centre-of-our-home-galaxy/

On this day five years ago, an international team led by researchers at @mpi_grav in Hannover, Germany, identified a Galactic “mystery source” of gamma rays.

It contains a heavy neutron star with a very low mass companion orbiting it. Using novel data analysis methods running on about 10,000 graphics cards in the distributed computing project @einsteinathome, the team identified the neutron star by its regularly pulsating gamma rays in a deep search of data from NASA's Fermi satellite.

➡️ https://www.aei.mpg.de/545717/superschwergewicht-und-fliegengewicht-im-kosmischen-tanz

📄 https://iopscience.iop.org/article/10.3847/2041-8213/abbc02 [Open Access]

Image: Artist's impression of the pulsar and its companion star, which is distorted by tidal forces, compared in size to the Earth-Moon system. (B. Knispel, C. Clark (@mpi_grav)/NASA)

#OTD #Astrophysics #Pulsar #FermiLAT #CitizenScience #OpenAccess

Heute vor fünf Jahren löste ein internationales Team unter Leitung von Forschenden des @mpi_grav in Hannover das Rätsel um eine galaktische Gammastrahlenquelle.

In ihr steckt ein schwerer Neutronenstern, den ein sehr leichter Begleiter umrundet. Mittels neuartiger Datenanalysemethoden, die auf rund 10.000 Grafikkarten im verteilten Rechenprojekt @einsteinathome liefen, wies das Team den Neutronenstern anhand seines regelmäßigen Gammastrahlenblinkens durch eine aufwändige Suche in Daten des Fermi-Satelliten der NASA eindeutig nach.

➡️ https://www.aei.mpg.de/544819/superschwergewicht-und-fliegengewicht-im-kosmischen-tanz

📄 https://iopscience.iop.org/article/10.3847/2041-8213/abbc02 [Open Access]

Bild: Künstlerische Darstellung des Pulsars mit seinem durch Gezeitenkräfte verzerrten Begleitstern im Größenvergleich mit dem Erde-Mond-System. (B. Knispel, C. Clark (@mpi_grav)/NASA)

#OTD #Astrophysik #Pulsar #FermiLAT #CitizenScience #OpenAccess

🎉 A new paper with Einstein@Home gamma-ray pulsar discoveries 🔭

The new publication “Einstein@Home Searches for Gamma-ray Pulsars in the Inner Galaxy” was accepted for publication in The Astrophysical Journal and is posted on the arXiv preprint server today.

📄 https://arxiv.org/abs/2509.21307

The international science team reports the discovery of four previously unknown gamma-ray pulsars towards the direction of the Galactic Center. Most likely the four discoveries are foreground sources from the Galactic disk.

🙏 We thank our volunteers, without the support of whom this research could not have happened.

All of our publications and PhD theses related to the project at https://einsteinathome.org/science/publications.

#Pulsars #NeutronStars #FermiLAT #GammaRays #CitizenScience