Weekly Update from the Open Journal of Astrophysics – 09/08/2025

It’s Saturday morning so, once again, it’s time for an update of papers published at the Open Journal of Astrophysics. Since the last update we have published four new papers, which brings the number in Volume 8 (2025) up to 114, and the total so far published by OJAp up to 349.

The papers published this week, with their overlays, are as follows. You can click on the images of the overlays to make them larger should you wish to do so.

The first paper to report is “Caught in the Act of Quenching? – A Population of Post-Starburst Ultra-Diffuse Galaxies” by Loraine Sandoval Ascencio & M. C. Cooper (UC Irvine), Dennis Zaritsky, Richard Donnerstein & Donghyeon J. Khim (U. Arizona) and Devontae C. Baxter (UC San Diego). This paper was puvblished on Monday 4th August and is in the folder marked Astrophysics of Galaxies. It discusses a sample of Ultra-Diffuse Galaxies (UDGs) found to be post-starburst galaxies through spectroscopic analysis analysis of candidates selected from the Systematically Measuring Ultra-Diffuse Galaxies (SMUDGes) program.

The overlay is here:

The officially-accepted version can be found on arXiv here.

Next one up, published on Tuesday 5th August, in the folder Cosmology and Nongalactic Astrophysics, is “Damping Wing-Like Features in the Spectra of High Redshift Quasars: a Challenge for Fully-Coupled Simulations” by Nick Gnedin & Hanjue Zhu (University of Chicago, USA).  This paper presents a discussion of the difficulties that cosmological radiation transfer codes have in accounting for the existence of “neutral islands” in the universe at relatively low redshifts.

The overlay is here:

You can find the officially accepted version of the paper on arXiv here.

The third paper of the week is “Spectroscopic Analysis of Pictor II: a very low metallicity ultra-faint dwarf galaxy bound to the Large Magellanic Cloud” by Andrew Pace (U. Virginia, USA) and 32 others based in the USA, UK, Canada, Chile and Spain. This one was also published on Tuesday 5th August but in the folder Astrophysics of Galaxies. It describes Magellan/IMACS and Magellan/MIKE spectroscopy of the ultra-faint dwarf (UFD) galaxy Pictor II, which is located only 12 kpc from the Large Magellanic Cloud (LMC).

The overlay is here:

The final version is on arXiv here.

The fourth, and final, paper of the week, also published on Thursday 7th August, is “ASASSN-24fw: An 8-month long, 4.1 mag, optically achromatic and polarized dimming event” by Raquel Forés-Toribio (Ohio State University) and 22 others based in the USA, Austria, Chile and Australia. It is published in the folder Solar and Stellar Astrophysics, and it presents an observational study of an unusual dimming event likely to have been caused by eclipsing of a binary system by a dusty disk.

Here is the overlay:

You can find the officially-accepted version on arXiv here.

And that’s all the papers for this week. I’ll do another update next Saturday.

P.S. For those of you who missed the post I did earlier in the week, I have been looking at the accounts for the Open Journal of Astrophysics and can confirm that the cost to us per paper is less than $30 and will reduce with scale. We expect to publish around 180 papers in 2025 for which the total cost incurred by OJAp will be around $5000. Obviously if we increase by a factor, say, ten then that amount would become significant so we are taking steps to secure additional funding in the event that happens.

#arXiv250200117v2 #arXiv250411539v2 #arXiv250621841v2 #arXiv250703080v2 #ASASSN #Astrophysics #AstrophysicsOfGalaxies #circumbinaryDisk #CosmicReionization #CosmologyAndNonGalacticAstrophysics #DiamondOpenAccess #DiamondOpenAccessPublishing #OpenAccess #OpenJournalOfAstrophysics #PictorII #PostStarburstGalaxies #quasars #SolarAndStellarAstrophysics #starFormation #TheOpenJournalOfAstrophysics #ultraDiffuseGalaxies #ultraFaintDwarfGalaxy

Weekly Update from the Open Journal of Astrophysics – 26/07/2025

It’s Saturday morning again, so it’s time again for an update of papers published at the Open Journal of Astrophysics. Since the last update we have published seven new papers, which brings the number in Volume 8 (2025) up to 105, and the total so far published by OJAp up to 340. I expect we’ll pass the century for this year sometime next week. I had expected a bit of a slowdown in July, but that doesn’t seem to have happened. Anyway, with the century for the year having been achieved, the next target is 120 (the total number we published last year). At the current rate I expect us to reach that sometime in August.

The papers published this week, with their overlays, are as follows. You can click on the images of the overlays to make them larger should you wish to do so.

The first paper to report is “Non-equilibrium ionization in the multiphase circumgalactic medium – impact on quasar absorption-line analyses” by Suyash Kumar and Hsiao-Wen Chen (University of Chicago, USA). This was published on Tuesday 22nd July 2025 in the folder Astrophysics of Galaxies. It discusses time-dependent photoionization (TDP) models that self-consistently solve for the ionization state of rapidly cooling gas irradiated by the extragalactic ultraviolet background (UVB) and the application thereof to observed systems.

The overlay is here:

The officially-accepted version can be found on arXiv here.

The second paper of the week, also published on Tuesday 22nd July but in the folder Cosmology and Nongalactic Astrophysics, is “Do We Know How to Model Reionization?” by Nick Gnedin (University of Chicago, USA). This paper discusses the similarities and differences between the radiation fields produced by different numerical simulations of cosmic reionization. The overlay is here:

You can find the officially accepted version of the paper on arXiv here.

The third paper of the week is “The effects of projection on measuring the splashback feature” by Xiaoqing Sun (MIT), Stephanie O’Neil (U. Penn.), Xuejian Shen (MIT) and Mark Vogelsberger (MIT), all based in the USA. This paper describes an investigation whether projection effects could lead to any systematic bias in determining the position of the boundary between infalling and accreting matter around haloes. It was published on Wednesday 23rd July in the folder Astrophysics of Galaxies. The overlay is here:

The officially-accepted version can be found on arXiv here.

The fourth paper of the week, also published on Wednesday 22nd July in the folder Astrophysics of Galaxies, is “Host galaxy identification of LOFAR sources in the Euclid Deep Field North” by Laura Bisigello, Marika Giulietti, Isabella Prandoni, Marco Bondi, & Matteo Bonato (INAF, Bologna, Italy), Manuela Magliocchetti (INAF-IAPS Roma, Italy), Huub Rottgering (Leiden Observatory, Netherlands), Leah, K. Morabito (Durham University, UK) and Glenn, J. White (Open Universirty, UK). This presents a catalogue of optical and near-infrared counterparts to radio sources detected in the Euclid Deep Field North using observations from the LOw-Frequency ARray (LOFAR). The overlay is here:

The final, accepted version of the paper is on arXiv here.

Fifth one up is “Constraining the dispersion measure redshift relation with simulation-based inference” by Koustav Konar (Ruhr University Bochum), Robert Reischke (Universität Bonn), Steffen Hagstotz (Ludwig-Maximilians Universität München), Andrina Nicola (Bonn) and Hendrik Hildebrandt (Bochum); all authors based in Germany. This was published on Thursday 24th July in the folder Cosmology and NonGalactic Astrophysics. It discusses using simulations to develop the use of Dispersion Measures of Fast Radio Bursts as cosmological probes. The overlay is here:

You can find the officially accepted version on arXiv here.

The penultimate (sixth) article published this week is “Generating Dark Matter Subhalo Populations Using Normalizing Flows” by Jack Lonergan (University of Southern California), Andrew Benson (Carnegie Observatories) and Daniel Gilman (University of Chicago), all based in the USA. This paper describes a generative AI approach to subhalo populations, trained using the semi-analytical model Galacticus. This paper was published yesterday (i.e. on Friday 25th July) in the folder Astrophysics of Galaxies.

You can find the final version on arXiv here.

The last article published this week is “21 Balmer Jump Street: The Nebular Continuum at High Redshift and Implications for the Bright Galaxy Problem, UV Continuum Slopes, and Early Stellar Populations” by Harley Katz of the University of Chicago, and 13 others based in the USA, UK, Germany, Denmark and Austria. This discusses the implications of extreme nebular emission for the spectroscopic properties of galaxies, especially at high redshift. It was published on Friday 25th July in the folder Astrophysics of Galaxies.

The overlay is here:

You can find the officially-accepted version on arXiv here.

And that’s all the papers for this week. I’ll do another update next Saturday, when we’ll be into August.

#arXiv241007084v2 #arXiv250113170v2 #arXiv250410571v2 #arXiv250415468v2 #arXiv250715963v1 #AstrophysicsOfGalaxies #CircumgalacticMedium #CosmicReionization #Cosmology #CosmologyAndNonGalacticAstrophysics #DiamondOpenAccess #Euclid #EuclidDeepFieldNorth #fastRadioBursts #galaxyHaloes #generativeAI #LOFAR #NebularEmission #OpenJournalOfAstrophysics #subhaloes #TheOpenJournalOfAstrophysics #UltravioletSpectroscopy

Weekly Update from the Open Journal of Astrophysics – 28/06/2025

It’s Saturday morning again so time for an update of papers published at the Open Journal of Astrophysics. Since the last update we have published eight new papers, which brings the number in Volume 8 (2025) up to 82, and the total so far published by OJAp  up to 317. With about half the year gone, we’re on target to published around 160 papers this year.

The papers published this week, with their overlays, are as follows.  You can click on the images of the overlays to make them larger should you wish to do so.

The first paper to report is “Spectroscopic and X-ray Modeling of the Strong Lensing Galaxy Cluster MACS J0138.0-2155” by Abigail Flowers (University of California at Santa Cruz; UCSZ), Jackson H. O’Donnell (UCSZ), Tesla E. Jeltema (UCSZ), Vernon Wetzell (U. Pennsylvania) & M. Grant Roberts (UCSZ). This artticle, which is in the folder marked Cosmology and NonGalactic Astrophysics, presents a study of the mass distribution and substructure of a galaxy cluster that acts as a gravitational lens for a source galaxy at z=1.95 that contains two supernovae. It was published on 23rd June 2025. The overlay is here:

The officially-accepted version can be found on arXiv here.

“Illuminating the Physics of Dark Energy with the Discovery Simulations” by Gillian D. Beltz-Mohrmann (Argonne National Laboratory, USA) and 12 others based in the USA and Spain. This describes new high-resolution cosmological simulations providing a testbed for alternative cosmological probes that may offer additional constraining power beyond Baryon Accoustic Oscillations. It is filed in the folder marked Cosmology and NonGalactic Astrophysics.

The overlay is here:

You can read the final accepted version on arXiv here.

Next one up is in the folder marked Astrophysics of Galaxies. The title is “On the minimum number of radiation field parameters to specify gas cooling and heating functions” and it is by David Robinson & Camille Avestruz (U. Michigan) and Nickolay Y. Gnedin (U.Chicago) and was published on 23rd June 2025. It presents an analysis using machine learning of atomic gas cooling and heating functions computed by the spectral synthesis code Cloudy.

The overlay is here:

You can find the officially-accepted version of the paper on arXiv here.

The thirtd paper is “On the Use of WGANs for Super Resolution in Dark-Matter Simulations” by John Brennan (Maynooth), Sreedhar Balu (U. Melbourne), Yuxiang Qin (ANU), John Regan (Maynooth) and Chris Power (U. Western Australia). This one is also in the folder marked Astrophysics of Galaxies and was also published on Monday 23rd June. It is about using the Wasserstein Generative Adversarial Network (WGAN) model to increase the particle resolution of dark-matter-only simulations of galaxy formation. The overlay is here:

You can find the officially-accepted version of the paper on arXiv here.

Next we have “Cosmic Rays Masquerading as Hot CGM Gas: An Inverse-Compton Origin for Diffuse X-ray Emission in the Circumgalactic Medium” by Philip F. Hopkins (Caltech), Eliot Quataert (Princeton), Sam B. Ponnada (Caltech) and Emily Silich (Caltech), all based in the USA.  This one was published on 24th June 2025 in the folder High-Energy Astrophysical Phenomena

You can find the officially-accepted version on arXiv here.

The fifth paper this week is “Compact Binary Formation in Open Star Clusters III: Probability of Binary Black Holes Hidden Inside of Gaia Black Hole Binary” by Ataru Tanikawa (Fukui Prefectural University, Japan), Long Wang (Sun Yat-sen University, China), Michiko S. Fujii (University of Tokyo, Japan), Alessandro A. Trani (Niels Bohr Institute, Denmark), Toshinori Hayashi (Kyoto University, Japan) and Yasushi Suto (Kochi University of Technology, Japan).  This one is in the folder marked Astrophysics of Galaxies and was published on Tuesday 24th June. It presents an investigation into whether some Gaia black hole binary systems may in fact involve three black holes, including a pair too compact to be resolved astrometrically. Here is the overlay:

You can find the officially-accepted paper on arXiv here.

Next we have “Rapid identification of lensed type Ia supernovae with color-magnitude selection” by Prajakta Mane (IISER) and Anupreeta More & Surhud More (IUCAA), all based in India. This paper presents an  extension of the use of color-magnitude diagrams, used previously as a means to identify lensed supernovae, with applications to LSST-like photometric data. It is in the folder marked Astrophysics of Galaxies and was published on Thursday 26th June.

The officially-accepted version of the article can be found on arXiv here.

The penultimate article this week is: “Cosmic Reionization On Computers: Biases and Uncertainties in the Measured Mean Free Path at the End Stage of Reionization” by Huanqing Chen (U. Alberta, Canada), and Jiawen Fan & Camille Avestruz (U. Michigan, USA). This one is in the folder Cosmology and Nongalactic Astrophysics and was published on 26th June 2025.  This paper studies possible systematic effects in computer simulations of cosmic reionization especially when it results from quasar radiation.

The overlay is here:

You can find the officially-accepted version on arXiv here.

Eighth and last paper this week is “Exploring the Core-galaxy Connection” by Isabele Lais de Souza Vitório (U. Michigan) and Michael Buehlmann, Eve Kovacs, Patricia Larsen, Nicholas Frontiere & Katrin Heitmann (Argonne National Laboratory, USA).  This one is in the folder Cosmology and Nongalactic Astrophysics and was published on Friday 27th June 2025 (i.e. yesterday).

The overlay is here:

You can find the officially-accepted version on arXiv here.

And that’s all the papers for this week. I do, however, have some more news to pass on. We are delighted to welcome two new recruits to our Editorial Board,  Dr Foteini Oikonomou of the Norwegian University of Science and Technology, who specializes in the application of particle physics theories to  high-energy astrophysical phenomena, and Dr Heloise Stevance of Oxford University (UK), who specializes in the interface between Machine Learning and Astrophysics.

#arXiv240619446v2 #arXiv240700268v4 #arXiv240703662v4 #arXiv241005372v3 #arXiv241109412v2 #arXiv241219955v2 #arXiv250113056v2 #arXiv250118696v2 #AstrophysicsOfGalaxies #BinaryBlackHoles #CircumgalacticMedium #cosmicRays #CosmicReionization #CosmologyAndNonGalacticAstrophysics #DiamondOpenAccessPublishing #DrHeloiseStevcance #GalacyHalos #galaxyClusters #galaxyFormation #HighEnergyAstrophysicalPhenomena #OJAp #OpenJournalOfAstrophysics #supernovae #TheOpenJournalOfAstrophysics #WAGN