It may be the Easter weekend, but it’s still time for a Saturday morning 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 71 and the total so far published by OJAp up to 519. This update coimpletes the first quarter of 2026, which suggests that if we continue to publish at the same rate we’ll reach about 280 for the year.
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.
New Publication at the Open Journal of Astrophysics: "Testing halo models for constraining astrophysical feedback with multi-probe modeling: I. 3D Power spectra and mass fractions" by Pranjal R. S. (U. Arizona, USA), Shivam Pandey Johns Hopkins U., USA), Dhayaa Anbajagane (U. Chicago, USA), Elisabeth Krause (U. Arizona) and Klaus Dolag (Max Planck Institute for Astrophysics, Germany)
The second paper for this week, also published on Tuesday March 31st in the folder Cosmology and Nongalactic Astrophysics, is “Validation of the DESI-DR1 3×2-pt analysis: scale cut and shear ratio tests” by Ni Putu Audita Placida Emas (Swinburne University of Technology, Australia) and an international cast of 56 others. This study validates the combined analysis of galaxy clustering and weak gravitational lensing data from various surveys, ensuring accurate tests of the standard cosmological model using future Stage-IV surveys
The overlay for this one is here:
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: "Validation of the DESI-DR1 3×2-pt analysis: scale cut and shear ratio tests" by Ni Putu Audita Placida Emas (Swinburne University of Technology, Australia) and an international cast of 56 others.
Next one up, the third paper of the week, also published on Tuesday March 31st in the folder Cosmology and Nongalactic Astrophysics, is “Differentiable Stochastic Halo Occupation Distribution with Galaxy Intrinsic Alignments” by Sneh Pandya and Jonathan Blazek (both of Northeastern University, USA). This is a paper introducing diffHOD-IA, a differentiable model for galaxy population analysis that incorporates intrinsic alignments and halo occupation distribution. It’s validated against existing models and can be used in next-generation weak-lensing analyses.
The overlay for this one is here:
The final, accepted version can be found on arXiv here and the Mastodon announcement is here:
New Publication at the Open Journal of Astrophysics: "Differentiable Stochastic Halo Occupation Distribution with Galaxy Intrinsic Alignments" by Sneh Pandya and Jonathan Blazek (Northeastern U., USA)
The fourth and final paper this week, published on Wednesday April 1st (but not a joke), is “The Growth of Dust in Galaxies in the First Billion Years with Applications to Blue Monsters” by Desika Narayanan (U. Florida, USA) and 11 others based in the USA and Europe. This one is in the folder Astrophysics of Galaxies; it presents a simulation-based study of dust accumulation in early galaxies via supernovae production and rapid growth on tiny dust grains, with local density and grain size being important factors.
The overlay is here:
The finally accepted version of this paper can be found here and the Mastodon announcement is here:
New Publication at the Open Journal of Astrophysics: "The Growth of Dust in Galaxies in the First Billion Years with Applications to Blue Monsters" by Desika Narayanan (U. Florida, USA) and 11 others based in the USA and Europe.
It’s Saturday once more, so it’s time for another update of activity at the Open Journal of Astrophysics. It has been a busy week. Since the last update we have published a further nine papers, bringing the number in Volume 9 (2026) to 45 and the total so far published by OJAp up to 493.
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 four papers this week were all published on Monday 23rd February.
New Publication at the Open Journal of Astrophysics: "A Bayesian Exploration of The Mass of the Ursa Major III: Kinematics, Rotation and their influence on the Mass to Light Ratio" by Tim R. Adams (U. Sydney, Australia), Brendon J. Brewer (U. Auckland, New Zealand) and Geraint F. Lewis (Sydney)
The second paper is “The Impact of Baryonic Effects on the Dynamical Masses Inferred Using Satellite Kinematics” by Josephine F.W. Baggen, Frank C. van den Bosch, and Kaustav Mitra (Yale U., USA). This paper, also in the folder Astrophysics of Galaxies, presents a model to assess the impact of stars and gas on satellite kinematics, showing that these baryonic effects can reduce the satellite velocity dispersion and increase inferred central galaxy masses.
The overlay for this one is here:
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 Impact of Baryonic Effects on the Dynamical Masses Inferred Using Satellite Kinematics" by Josephine F.W. Baggen, Frank C. van den Bosch, and Kaustav Mitra (Yale U., USA)
The third paper this week, and the third published on Monday 23rd February, and the third in the folder Astrophysics of Galaxies, is “MEGATRON: Disentangling Physical Processes and Observational Bias in the Multi-Phase ISM of High-Redshift Galaxies” by Nicholas Choustikov (U. Oxford, UK) and 12 others based in UK, USA, France, Korea and Belgium. The study uses MEGATRON simulations to analyze the interstellar medium (ISM) of high-redshift galaxies, finding it denser and less metal-enriched than local galaxies with implications for line ratios as diagnostics
The overlay is here:
The official version can be found on arXiv here and the Fediverse announcement is here:
New Publication at the Open Journal of Astrophysics: "MEGATRON: Disentangling Physical Processes and Observational Bias in the Multi-Phase ISM of High-Redshift Galaxies" by Nicholas Choustikov (U. Oxford, UK) and 12 others based in UK, USA, France, Korea and Belgium
New Publication at the Open Journal of Astrophysics: "Redshift Assessment Infrastructure Layers (RAIL): Rubin-era photometric redshift stress-testing and at-scale production" by the RAIL Team (31 authors) and the Dark Energy Science Collaboration
Moving on to Tuesday 24th February, the fifth paper this week, is “Feedback shaped the galaxy morphological sequence in presence of mergers” by Masafumi Noguchi (Tohoku University, Japan). This article was published in the folder Astrophysics of Galaxies. This study suggests that galaxy morphology, specifically the mass ratios of bulges and disks, is influenced by galaxy mergers and feedback processes from active galactic nuclei and supernovae.
The overlay is here:
The accepted version can be found on arXiv here, and the fediverse announcement is here:
New Publication at the Open Journal of Astrophysics: "Feedback shaped the galaxy morphological sequence in presence of mergers" by Masafumi Noguchi (Tohoku University, Japan)
The sixth paper this week is “HelioSpectrotron 5000: an interactive solar atlas” by Alexander G.M. Pietrow (AIP Potsdam, Germany). This was published on Tuesday 24th February in the folder Solar and Stellar Astrophysics. This describes HelioSpectrotron~5000 (HS5000), which is an interactive solar spectral atlas that allows comparison between high-resolution spectra and ground-based instrument observations, aiding in wavelength calibration and line identification. The software can be found here; I had a play with it yesterday and it’s very easy to use!
The overlay is here:
You can find the officially accepted version on arXiv here and the Mastodon announcement is here:
New Publication at the Open Journal of Astrophysics: "HelioSpectrotron 5000: an interactive solar atlas" by Alexander G.M. Pietrow (AIP Potsdam, Germany)
The seventh paper of this week was published on Thursday 26th February is “The Rise of Ionized Gas Filaments in Early-Type Galaxies” by Ryan Eskenasy (U. Kentucky, USA), Valeria Olivares (Universidad de Santiago de Chile) and Yuanyuan Su (U. Kentucky, USA). This article, in the folder Astrophysics of Galaxies, is an exploration of the formation of multiphase filamentary nebulae in early-type galaxies (ETGs), using VLT-MUSE IFU observations of 126 non-central ETGs, focussing on the hot gas components thereof.
The overlay is here:
The officially accepted version of this paper can be found on the arXiv here and the Mastodon announcement is here:
New Publication at the Open Journal of Astrophysics: "The Rise of Ionized Gas Filaments in Early-Type Galaxies" by Ryan Eskenasy (U. Kentucky, USA), Valeria Olivares (Universidad de Santiago de Chile) and Yuanyuan Su (U. Kentucky, USA)
New Publication at the Open Journal of Astrophysics: "Relationship Between Major Stellar Physical Parameters and Normal Mode Frequencies in Accreting White Dwarf Stars" by Praphull Kumar, Dean M. Townsley and Hunter Anz (U. Alabama, USA)
The ninth, and final, paper for this week is “A Semi-Supervised Learning Method for the Identification of Bad Exposures in Large Imaging Surveys” by Yufeng Luo (U. Wyoming, USA) and 8 others from the DESI Legacy Imaging Surveys Team. This was published on Friday 27th February, i.e yesterday, in the folder Instrumentation and Methods for Astrophysics. The paper describes a machine-learning approach for detecting poor-quality exposures in large astronomical imaging surveys, proving efficient and accurate in identifying problematic exposures.
The overlay is here:
The official version on arXiv can be found here and the Mastodon announcement follows:
New Publication at the Open Journal of Astrophysics: "A Semi-Supervised Learning Method for the Identification of Bad Exposures in Large Imaging Surveys" by Yufeng Luo (U. Wyoming, USA) and 8 others from the DESI Legacy Imaging Surveys Team
And that concludes this week’s update. We have now published 45 papers in two complete months of 2026, on which basis we can estimate about 270 papers in the year. For the record, in the first two months of 2025 we published 21 papers.
P.S. Thank you to the many people who responded to the latest call for editors. I’ve been sending out invitations and getting people onboard as quickly as I can, but I still have a number to get to so please bear with me!
This morning’s arXiv announcement contained a number of papers related to the Dark Energy Survey Y6 analysis. There is also a Zoom webinar later today at 10.30 Central Time (16.30 GMT; 13.30 in Greenland). Details can be found here.
You can find links to and abstracts of all the papers here, but I thought it would be useful to provide arXiv links to the latest batch here.
arXiv:2601.14559 Dark Energy Survey Year 6 Results: Cosmological Constraints from Galaxy Clustering and Weak Lensing – this is the key summary paper.
arXiv:2601.14484 Dark Energy Survey Year 6 Results: MagLim++ Lens Sample Selection and Measurements of Galaxy Clustering
arXiv:2601.14864 Dark Energy Survey: DESI-Independent Angular BAO Measurement
arXiv:2601.15175 Dark Energy Survey Year 6 Results: Galaxy-galaxy lensing
arXiv:2601.14833 Dark Energy Survey Year 6 Results: Magnification modeling and its impact on galaxy clustering and galaxy-galaxy lensing cosmology
arXiv:2601.14859 Dark Energy Survey Year 6 Results: Weak Lensing and Galaxy Clustering Cosmological Analysis Framework
I’ll just highlight a couple of points from the first paper listed above, which uses the now standard “3x2pt” analysis, which combines three complementary two-point correlation functions: cosmic shear; galaxy-galaxy lensing and galaxy clustering. The abstract of this paper is as follows:
A notable result is contained in the last sentence. The simplest interpretation of dark energy is that it is a cosmological constant (usually called Λ) which – as explained here – corresponds to a perfect fluid with an equation-of-state p=wρc2 with w=-1. In this case the effective mass density ρ of the dark energy remains constant as the universe expands. To parametrise departures from this constant behaviour, cosmologists have replaced this form with the form w(a)=w0+wa(1-a) where a(t) is the cosmic scale factor. A cosmological constant Λ would correspond to a point (w0=-1, wa=0) in the plane defined by these parameters, but the only requirement for dark energy to result in cosmic acceleration is that w<-1/3, not that w=-1. Results last year from DESI suggested values of w0 ≠-1 and wa≠0 , but the current DES results are consistent with w=-1; they do not constrain w0 and wa jointly.
For reference on the left you can find the (w0, wa) plane from DESI.
I thought I’d add one of the other cosmological contraint plots:
The results look qualitatively similar to previous plots but the contours have shifted a bit.
It may be a Bank Holiday weekend here in Ireland, but it’s still time for the usual Saturday update of the week’s new papers at the Open Journal of Astrophysics (although a bit later in the day than usual). Since the last update we have published another five papers, which brings the number in Volume 8 (2025) up to 161, and the total so far published by OJAp up to 396.
This week’s update is rather unusual because there are four papers in a series (or, more precisely, mathematically speaking, a sequence) all published on the same day (Wednesday October 22nd 2025), in the same folder (Cosmology and NonGalactic Astrophysics), with the same first author (Dhayaa Anbajagane of the University of Chicago), with long author lists and many co-authors in common. These papers all relate to the DECADE cosmic shear project. Instead of doing them one by one, therefore, I’ve decided to put all four overlays together and provide links to all the papers afterwards. As I’m trying to encourage people to follow our feed on the Fediverse via Mastodon (where I announce papers as they are published, including the all-important DOI), I’ll include links to each announcement there too.
New Publication at the Open Journal of Astrophysics: "The DECADE cosmic shear project I: A new weak lensing shape catalog of 107 million galaxies" by Dhayaa Anbajagane (University of Chicago, USA) et al. (54 authors)
New Publication at the Open Journal of Astrophysics: "The DECADE cosmic shear project II: photometric redshift calibration of the source galaxy sample" by Dhayaa Anbajagane (University of Chicago, USA) et al. (53 authors)
New Publication at the Open Journal of Astrophysics: "The DECADE cosmic shear project III: validation of analysis pipeline using spatially inhomogeneous data" by Dhayaa Anbajagane (University of Chicago, USA) et al. (53 authors)
New Publication at the Open Journal of Astrophysics: "The DECADE cosmic shear project IV: cosmological constraints from 107 million galaxies across 5,400 deg^2 of the sky" by Dhayaa Anbajagane (University of Chicago, USA) et al. (75 authors)
The fifth and final paper for this week is “Clustering of DESI galaxies split by thermal Sunyaev-Zeldovich effect” by Michael Rashkovetskyi of the Harvard-Smithsonian Center for Astrophysics, or CfA for short, and 48 others. This one was published on Wednesday 23rd October in the folder Cosmology and NonGalactic Astrophysics. This paper explores how the clustering properties of galaxies mapped by the Dark energy Spectroscopic Instrument (DESI) relate to the local thermal Sunyaev-Zeldovich emission mapped by the Atacama Cosmology Telescope (ACT). The overlay is here:
The officially accepted version can be found on arXiv here, and the fediverse announcement is here:
New Publication at the Open Journal of Astrophysics: "Clustering of DESI galaxies split by thermal Sunyaev-Zeldovich effect" by Michael Rashkovetskyi (Cfa Harvard-Smithsonian, USA) et al. (49 authors)
It’s Saturday so, once again, it’s time for the weekly update of papers published at the Open Journal of Astrophysics. Since the last update we have published three new papers, which brings the number in Volume 8 (2025) up to 85, and the total so far published by OJAp up to 320.
The three 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 “Stellar reddening map from DESI imaging and spectroscopy” by Rongpu Zhou (Lawrence Berkeley National Laboratory, USA) and an international case of 56 others too numerous to mention individually. This paper was published on 1st July 2025 in the folder marked Astrophysics of Galaxies. It describes maps of stellar reddening by Galactic dust inferred from observations obtained using the Dark Energy Spectroscopic Instrument, and a comparison with previous such maps. The overlay is here:
You can find the final, accepted, version on arXiv here.
Next one up is “On inertial forces (indirect terms) in problems with a central body” by Aurélien Crida (Université Côte d’Azur, France) and 17 others – again too numerous to be listed individually – based in France, Italy, Germany, Mexico and the USA. This paper discusses the indirect terms that arise the Newtonian dynamics of multi-body systems dominated by a central massive body, upon which other bodies exert a gravitational pull, when the massive body is treated as the origin of the coordinate system. This one, also published on July 1st 2025, is in the folder marked Earth and Planetary Astrophysics.
The overlay is here:
You can find the officially accepted version on arXiv here.
Time for the weekly Saturday morning 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 25 and the total so far published by OJAp up to 260.
In chronological order of publication, the four 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 “Partition function approach to non-Gaussian likelihoods: information theory and state variables for Bayesian inference” by Rebecca Maria Kuntz, Heinrich von Campe, Tobias Röspel, Maximilian Philipp Herzog, and Björn Malte Schäfer, all from the University of Heidelberg (Germany). It was published on Wednesday March 5th 2025 in the folder Cosmology and NonGalactic Astrophysics and it discusses the relationship between information theory and thermodynamics with applications to Bayesian inference in the context of cosmological data sets.
You can read the officially accepted version of this paper on arXiv here.
The second paper of the week is “The Cosmological Population of Gamma-Ray Bursts from the Disks of Active Galactic Nuclei” by Hoyoung D. Kang & Rosalba Perna (Stony Brook), Davide Lazzati (Oregon State), and Yi-Han Wang (U. Nevada), all based in the USA. It was published on Thursday 6th March 2025 in the folder High-Energy Astrophysical Phenomena. The authors use models for GRB electromagnetic emission to simulate the cosmological occurrence and observational detectability of both long and short GRBs within AGN disks
You can find the officially accepted version of this paper on arXiv here.
The next two papers were published on Friday 7th March 2025.
The official published version can be found on the arXiv here.
The last paper to report this week is “The DESI-Lensing Mock Challenge: large-scale cosmological analysis of 3×2-pt statistics” by Chris Blake (Swinburne, Australia) and 43 others; this is a large international collaboration and I apologize for not being able to list all the authors here!
This one is in the folder marked Cosmology and NonGalactic Astrophysics; it presents an end-to-end simulation study designed to test the analysis pipeline for the Dark Energy Spectroscopic Instrument (DESI) Year 1 galaxy redshift dataset combined with weak gravitational lensing from other surveys.
Some weeks ago I posted an item about recent results that have emerged from the DESI (Dark Energy Spectroscopic Instrument) Collaboration. I have been a bit busy since then but I just saw that there is one of those Cosmology Talks about these results which I thought I would pass on. The contributors are Arnaud de Mattia, Hector Gil-Marín and Pauline Zarrouk and they are talking about the analsysis they have done using the “full shape” of the galaxy power spectrum. It’s quite a long video, but very illuminating.
The Mayall Telescope at Kitt Peak, in which DESI is housed. This PR image was taken during a meteor shower, which is not ideal observing conditions. Picture Credit: KPNO/NOIRLab/NSF/AURA/R. Sparks
I’ve just got time between meetings to mention that a clutch of brand new papers has emerged from the DESI (Dark Energy Spectroscopic Instrument) Collaboration. There is a press release discussing the results from the Lawrence Berkeley Laboratory here and one from the ICCUB in Barcelona here; several members of the group I visited there during sabbatical are working on DESI. Congratulations to them.
I haven’t had time to read them yet, but a quick skim suggests that the results are consistent with the standard cosmological model.
The latest batch contains three Key Publications:
DESI Collaboration et al., DESI 2024 II: Sample Definitions, Characteristics, and Two-point Clustering Statistics
Findlay et al. (2024), Exploring HOD-dependent systematics for the DESI 2024 Full-Shape galaxy clustering analysis
The links lead to the arXiv version of these papers. These articles can also be found, along with previously released publications by the DESI Collaboration, here.
Anyone who has read the latest papers is welcome to comment through the box below!
A few months ago I posted an item about the release new results from the Dark Energy Spectroscopic Instrument (DESI). That was then followed by a presentation explaining the details which you can find here to find out more about the techniques involved. At the time the new DESI results garnered a lot of media attention much of it about claims that the measurements provided evidence for “New Physics”, such as evolving dark energy. Note that the DESI results themselves did not imply this. Only when combined with supernova measurements did this suggestion arise.
Now there’s a new preprint out by George Efstathiou of Cambridge. The abstract is here:
Recent results from the Dark Energy Spectroscopic Instrument (DESI) collaboration have been interpreted as evidence for evolving dark energy. However, this interpretation is strongly dependent on which Type Ia supernova (SN) sample is combined with DESI measurements of baryon acoustic oscillations (BAO) and observations of the cosmic microwave background (CMB) radiation. The strength of the evidence for evolving dark energy ranges from ~3.9 sigma for the Dark Energy 5 year (DES5Y) SN sample to ~ 2.5 sigma for the Pantheon+ sample. Here I compare SN common to both the DES5Y and Pantheon+ compilations finding evidence for an offset of ~0.04 mag. between low and high redshifts. Correcting for this offset brings the DES5Y sample into very good agreement with the Planck LCDM cosmology. Given that most of the parameter range favoured by the uncorrected DES5Y sample is discrepant with many other cosmological datasets, I conclude that the evidence for evolving dark energy is most likely a result of systematics in the DES5Y sample.
Here are a couple of figures from the paper illustrating the difference in parameter constraints using the uncorrected (left) and corrected (right) Dark Energy (Survey) 5 year Supernova sample.
The y-axis shows a parameter wa, which is zero in the standard model with non-evolving dark energy; the non-zero value implied by the left hand panel using the uncorrected data.
Just as with the Hubble Tension I blogged about yesterday, the evidence for a fundamental revision of our standard model may be nothing of the sort but some kind of systematic error. I think we can expect a response from the Dark Energy Survey (DES) team. Grab your popcorn.
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In the Dark 