Archive for metallicity

Weekly Update from the Open Journal of Astrophysics – 28/03/2026

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , on March 28, 2026 by telescoper

Once again it’s time for the usual Saturday morning update of activity at the Open Journal of Astrophysics. Since the last update we have published a further eight papers, bringing the number in Volume 9 (2026) to 67 and the total so far published by OJAp up to 515.

I will continue to include the posts made on our Mastodon account (on Fediscience) to encourage you to visit it. Mastodon is a really excellent service, and a more than adequate replacement for X/Twitter (which nobody should be using); these announcements also show the DOI for each paper.

The first paper to report this week is”Constraining Brown Dwarf Desert Formation Mechanisms through Bayesian Statistical Comparison of Observed and Simulated Populations” by Behrooz Karamiqucham (College of Charleston, USA). This paper was published on Tuesday March 24th in the folder Earth and Planetary Astrophysics. It presents a Bayesian statistical analysis exploring why brown dwarf companions are rarely found at orbital separations <5 AU. The results suggest that brown dwarfs form at wider separations then migrate.

The overlay is here:

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

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Constraining Brown Dwarf Desert Formation Mechanisms through Bayesian Statistical Comparison of Observed and Simulated Populations" by Behrooz Karamiqucham (College of Charleston, USA)

doi.org/10.33232/001c.159460

March 24, 2026, 7:10 am 1 boosts 1 favorites

The second paper for this week, also published on Tuesday March 24th, but in the folder Astrophysics of Galaxies, is “JWST observes the assembly of a massive galaxy at z ~ 4” by Aayush Saxena (University of Oxford, UK) and 20 others (based in the UK, Europe, USA, Brazil, Japan and China). The paper presents observations of radio galaxy TGSSJ1530+1049, revealing it as part of a dense structure of emitting objects likely to merge to form a massive galaxy within a few Gyr.

The overlay for this one is here:

The official version of the paper can be found on arXiv here and the Fediverse announcement here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "JWST observes the assembly of a massive galaxy at z ~ 4" by Aayush Saxena (University of Oxford, UK) and 20 others (based in the UK, Europe, USA, Brazil, Japan and China)

doi.org/10.33232/001c.159461

March 24, 2026, 7:25 am 1 boosts 1 favorites

Next one up, the third paper of the week, also published on Tuesday March 24th in the folder Astrophysics of Galaxies, is “The dawn is quiet II: Gaia XP constraints on the Milky Way’s proto-Galaxy from very metal-poor MDF tails” by Boquan Chen (Ohio State U., USA), Matthew D. A. Orkney (Universitat de Barcelona, Spain), Yuan-Sen Ting (Ohio State U.) & Michael R. Hayden (U. Oklahoma, USA). The paper aegues that the Milky Way’s metallicity distribution suggests that its early evolution involved a moderate gas reservoir, sustained by weak continuous inflow, and star formation efficiency similar to the present value.

The overlay for this one is here:

The final, accepted version can be found on arXiv here and the Mastodon announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "The dawn is quiet II: Gaia XP constraints on the Milky Way’s proto-Galaxy from very metal-poor MDF tails" by Boquan Chen (Ohio State U., USA), Matthew D. A. Orkney (Universitat de Barcelona, Spain), Yuan-Sen Ting (Ohio State U.) & Michael R. Hayden (U. Oklahoma, USA)

doi.org/10.33232/001c.159462

March 24, 2026, 7:41 am 1 boosts 1 favorites

The fourth paper this week, published on Wednesday 25th March 2026 in the folder High-Energy Astrophysical Phenomena is “Shaping the diffuse X-ray sky: Structure, Variability and Visibility” by Philipp Girichidis (Heidelberg U., Germany) and 7 others based in Germany, USA, Austria and Italy. The paper argues that the X-ray properties of the Local Bubble (LB), a low-density cavity in the solar neighborhood reveal that supernova events significantly influence X-ray emissions, which show pronounced temporal variability

The overlay is here:

The finally accepted version of this paper can be found here and the Mastodon announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Shaping the diffuse X-ray sky: Structure, Variability and Visibility" by Philipp Girichidis (Heidelberg U., Germany) and 7 others based in Germany, USA, Austria and Italy

doi.org/10.33232/001c.159505

March 25, 2026, 8:40 am 1 boosts 0 favorites

The fifth paper this week, also published on Wednesday 25th March 2026, is “Graph-Based Light-Curve Features for Robust Transient Classification” by Jesús D. Petro-Ramos David J. Ruiz-Morales, David Sierra Porta (Universidad Tecnológica de Bolívar, Colombia). This paper, which is in the folder Instrumentation and Methods for Astrophysics, uses graph-based representations of astronomical light curves for transient classification, achieving competitive multiclass performance, highlighting the potential of visibility graphs as a survey-agnostic tool for classifying time series.

This is the overlay:

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

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Graph-Based Light-Curve Features for Robust Transient Classification" by Jesús D. Petro-Ramos David J. Ruiz-Morales, David Sierra Porta (Universidad Tecnológica de Bolívar, Colombia)

doi.org/10.33232/001c.159506

March 25, 2026, 8:57 am 1 boosts 1 favorites

The sixth paper this week is “Redshift-Frame Systematics and Their Impact on the Hubble Constant from Pantheon+ Supernovae” by Said Laaroua (Santa Rosa Junior College, USA)This was published on Thursday 26th March in the folder Cosmology and Nongalactic Astrophysics. The study analyzes redshift-frame transformations in the Pantheon+ Type Ia supernova sample, finding a negligible shift in the Hubble constant, thus limiting redshift-frame systematics.

The overlay is here:

The officially accepted version of this paper can be found on arXiv here, and the Mastodon announcement is here:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Redshift-Frame Systematics and Their Impact on the Hubble Constant from Pantheon+ Supernovae" by Said Laaroua (Santa Rosa Junior College, USA)

doi.org/10.33232/001c.159558

March 26, 2026, 7:22 am 1 boosts 0 favorites

The penultimate, that is to say the seventh, paper for this week is “Why Machine Learning Models Systematically Underestimate Extreme Values II: How to Fix It with LatentNN” by Yuan-Sen Ting (Ohio State University, USA). The paper introduces LatentNN, a method that reduces attenuation bias in neural networks by optimizing network parameters and latent input values, improving inference in low signal-to-noise astronomical data; the code is available here. This article was published on Thursday 26th March 2026 in the folder Instrumentation and Methods for Astrophysics

The overlay for this one is here:

The official version of this paper can be found here. This is the Mastodon announcement:

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Why Machine Learning Models Systematically Underestimate Extreme Values II: How to Fix It with LatentNN" by Yuan-Sen Ting (Ohio State University, USA)

doi.org/10.33232/001c.159559

March 26, 2026, 7:36 am 2 boosts 1 favorites

And finally for this week, published yesterday (Friday 27th March 2026) in the folder Astrophysics of Galaxies, we have “Catalog of Mock Stellar Streams in Milky Way-Like Galaxies” by Colin Holm-Hansen, Yingtian Chen and Oleg Y. Gnedin (University of Michigan, USA).

Here is the overlay for this one:

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

Open Journal of Astrophysics

New Publication at the Open Journal of Astrophysics: "Catalog of Mock Stellar Streams in Milky Way-Like Galaxies" by Colin Holm-Hansen, Yingtian Chen and Oleg Y. Gnedin (University of Michigan, USA)

doi.org/10.33232/001c.159598

March 27, 2026, 8:44 am 1 boosts 1 favorites

And that concludes the update for this week.

You will have pbserved that this week’s papers cover five of the six main categories on astro-ph. We haven’t yet managed to cover all six in a week – we only missed Solar and Stellar Astrophysics this time!

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.

New Publication at the Open Journal of Astrophysics!

Posted in Maynooth, OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , on August 24, 2020 by telescoper

So another new paper has been published in the Open Journal of Astrophysics! This one is in the folder marked Astrophysics of Galaxies and is entitled Massive Star Formation in Metal-Enriched Haloes at High Redshift. I should explain that “Metal” here is the astrophysicist’s definition which basically means anything heavier than hydrogen or helium: chemists may look away now.

The authors of this paper are John Regan (of the Department of Theoretical Physics at Maynooth University), Zoltán Haiman (Columbia), John Wise (Georgia Tech), Brian O’Shea (Michigan State) and Michael Norman (UCSD). And before anyone asks, no I don’t force members of staff in my Department to submit papers to the Open Journal of Astrophysics and yes I did stand aside from the Editorial process because of the institutional conflict.

Here is a screen grab of the overlay:

You can click on the image to make it larger should you wish to do so.

You can find the arXiv version of the paper here.