In the DarkJun 11

Euclid, Gravitational Lensing, and Dark Matter

I’ve been slow onto a result which was announced last week concerning the detection weak gravitational lensing in the cluster Abell 2390 by the Euclid spacecraft and its use to determine the distribution of dark matter in the cluster. You can find a full discussion of the result here and the scientific paper is here.

The analysis was based on Early Release Observations of the cluster, a pretty picture of which are shown here:

Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi.

(The little blue patches are artefacts caused by internal reflections in the VIS instrument and can be dealt with in software.)

According to general relativity, the presence of any mass bends the path of light passing near it, producing gravitational lensing. The most famous examples of this are the giant arcs and multiple images associated with strong gravitational lensing, but these are very rare as they require good alignment between observer, lens and source.. Most lines of sight in the universe do not satisfy this condition so are in the weak lensing regime. Even in such cases, however, the presence of the foreground mass can be detected, by way of a systematic alignment in the orientation of background sources around the lensing mass. A circular background image would be distorted into an ellipse by this process. Unfortunately galaxies aren’t circular but are approximately elliptical, so the shape of each source is changed from an ellipse to differently shaped ellipse. The distortion is therefore impossible to detect in a single background source because we don’t know the intrinsic orientation of the galaxy, but the distortion of different sources is correlated in a particular way. Weak gravitational lensing is thus an intrinsically statistical measurement, but it provides a way to measure the masses of astronomical objects without requiring assumptions about their composition or dynamical state. Weak gravitational lensing observations are, however technically difficult to carry out and analyse, as one has to be very careful that no correlations are introduced by systematic errors in the optics.

Anyway, they say that a picture paints a thousand words so here are two pictures. On the left we see the shear axes as extracted from the above image and on the right the inferred dark matter distribution. You can slide the bar backwards and forwards to see how the two images relate.

Shear map (left) and inferred dark matter distribution (right)

You can see that the shear tends to be aligned tangentially to a line connecting the image to the cluster centre (in the plane of the sky), which is what theory would predict.

There’ll be much more of this sort of analysis in the full Euclid Survey. I hope to be able to give an update about this reasonably soon.

#Abell2390 #EuclidEarlyReleaseObservations #weakGravitationalLensing
In the DarkMay 30

Weekly Update from the Open Journal of Astrophysics – 30/05/2026

It’s Saturday once again, so it’s time for another 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 114 and the total so far published by OJAp up to 562.

I will continue to include the posts made on our Mastodon account (on Fediscience); these announcements also show the DOI for each paper.

The first paper to report this week, published on Monday 25th May is “Little Red Dot – Host Galaxy = Black Hole Star: A Gas-Enshrouded Heart at the Center of Every Little Red Dot” by Wendy Q. Sun (MIT, USA) and 32 others from around the world. This study presents evidence that “black hole stars” (BH*), early stages of black hole growth, power Little Red Dots (LRDs) and every massive black hole may have been a BH*.

The overlay for this paper is here

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

https://fediscience.org/@OJ_Astro/116633975428093674

The second paper for this week, also published on Monday 25th May but in the folder Cosmology and Nongalactic Astrophysics, is “Catalog-based detection of unrecognized blends in deep optical ground based imaging” by Shuang Liang (Stanford U., USA) and Prakruth Adari & Anja von der Linden (Stony Brook U., USA) on behalf of the LSST Dark Energy Science Collaboration. The study uses machine learning to detect unrecognized blends in deep ground-based imaging, improving sample purity and potentially enhancing accuracy in future cosmological 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:

https://fediscience.org/@OJ_Astro/116634039240557325

Next one up, the third paper of the week, published on Tuesday 26th May in the folder Cosmology and Nongalactic Astrophysics is “Control variates from Eulerian and Lagrangian perturbation theory: Application to the bispectrum” by Nickolas Kokron and Shi-Fan Chen (Institute for Advanced Study, Princeton, USA). This paper hexplores the use of control variates in cosmological simulations, introducing a new ‘shifted control variate’ that improves precision and enables accurate bispectrum emulators, aiding in cosmology modeling.

The overlay for this one is here:

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

https://fediscience.org/@OJ_Astro/116594304124291605

The fourth and final paper this week, also published on Tuesday 26th May is “How precisely can we measure the ages of subgiant and giant stars?” by Cheyanne Shariat, Kareem El-Badry and Soumyadeep Bhattacharjee (California Institute of Technology, USA). This article, published in the folder Solar and Stellar Astrophysics, is about testing the accuracy of stellar age estimates from recent catalogs, finding that spectroscopic metallicities provide reliable subgiant ages, while photometric ages underestimate uncertainties. Accurate chemical abundance measurements are essential.

The overlay is here:

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

https://fediscience.org/@OJ_Astro/116639604621500984

And that concludes this week’s update. I’ll do another one next Saturday.

#arXiv250316680v2 #arXiv251007375v2 #arXiv251008675v4 #arXiv260120929v2 #AstrophysicsOfGalaxies #bispectrum #blendedImages #controlVariates #cosmicShear #cosmologicalSimulations #CosmologyAndNonGalacticAstrophysics #DiamondOpenAccess #DiamondOpenAccessPublishing #LSSTDarkEnergyScienceCollaboration #OpenAccess #OpenAccessPublishing #SolarAndStellarAstrophysics #VeraCRubinObservatory #weakGravitationalLensing
In the DarkMay 23

Weekly Update from the Open Journal of Astrophysics – 23/05/2026

It’s Saturday once again, so time for another update of activity at the Open Journal of Astrophysics. Since the last update we have published a further six papers, bringing the number in Volume 9 (2026) to 110 and the total so far published by OJAp up to 558.

I will continue to include the posts made on our Mastodon account (on Fediscience); these announcements also show the DOI for each paper.

The first paper to report this week, published on Monday 18th May in the folder Instrumentation and Methods for Astrophysics is “Edges In Coadded Images” by Erin Sheldon (Brookhaven National Laboratory, USA). This paper describes a study exploring how image discontinuities and noise impact weak gravitational lensing measurements, finding no significant biases under typical conditions. Biases occur only in extreme cases, but can be mitigated.

The overlay for this paper is here

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

https://fediscience.org/@OJ_Astro/116594222032390191

The second paper for this week, also published on Monday 18th May but in the folder Cosmology and Nongalactic Astrophysics, is “Joint cosmological fits to DESI-DR1 full-shape clustering and weak gravitational lensing in configuration space” by A. Semenaite (Swinburne Institute of Technology, Australia) and 72 other authors from all round the world. This paper presents a cosmological analysis of correlations between the DESI-DR1 Bright Galaxy Survey and Luminous Red Galaxy samples and overlapping shear measurements from various weak lensing 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:

https://fediscience.org/@OJ_Astro/116594256215421009

Next one up, the third paper of the week, and the third published on Monday 18th May, and in the folder Cosmology and Nongalactic Astrophysics is “Probing Dark Energy Microphysics with kSZ Tomography” by Julius Adolff, Selim Hotinli and Neal Dalal (all of the Perimeter Institute, Canada). This paper explores how kinetic Sunyaev-Zel’dovich tomography and galaxy clustering can enhance our understanding of dark energy and its effects, potentially revealing its microphysical properties in future surveys.

The overlay for this one is here:

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

https://fediscience.org/@OJ_Astro/116594304124291605

The fourth paper this week, published on Wednesday May 20th is “A Census of Variable Radio Sources at 3 GHz” by Yjan A. Gordon, Peter S. Ferguson, Michael N. Martinez and Eric J. Hooper (all of the University of Wisconsin, USA). This article, published in the folder Astrophysics of Galaxies, uses data from the Very Large Array Sky Survey to analyze variability in the radio sky, finding most changes consistent with blazars and quasars.

The overlay is here:

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

https://fediscience.org/@OJ_Astro/116607468481260244

The fifth article of this week was published on Friday 22nd May in the folder Instrumentation and Methods for Astrophysics. The title is “Uncovering the Next Galactic Supernova with the Vera C. Rubin Observatory” by John Banovetz (Lawrence Berkeley Lab., USA), Claire-Alice Hebert & Peter B. Denton (Brookhaven National Lab., USA), Dan Scolnic (Duke University, USA), Anze Slosar (Brookhaven) and Chris Walter (Duke). The paper presents a study simulating how effectively the Vera C. Rubin Observatory can localize supernovae using neutrino triggers, finding a 57-97% success rate based on stellar mass density predictions.

The overlay is here:

You can find the authorized version of this paper on arXiv here and the Fediverse announcement is here:

https://fediscience.org/@OJ_Astro/116617293753093751

Last, but by no means least, this week we have “Pulsar timing solutions for 17 pulsars at 150 MHz from the Irish LOFAR station” by David J. McKenna (ASTRON, The Netherlands), Evan F. Keane (Trinity College Dublin, Ireland), Peter T. Gallagher (DIAS, Ireland) and Joe McCauley (Trinity). This was published on Friday 22nd May in the folder High-Energy Astrophysical Phenomena. It presents a demonstration of the use of international Low Frequency Array (LOFAR) stations in tracking and characterizing pulsars, providing new insights into these neutron stars’ emission properties.

The overlay for this one is here:

You can find the authorized version of this paper on arXiv here and the Fediverse announcement is here:

https://fediscience.org/@OJ_Astro/116617404344791486

And that concludes this week’s update. I’ll do another one next Saturday.

#arXiv250800976v2 #arXiv250906929v3 #arXiv251105653v2 #arXiv251215961v2 #arXiv260112094v2 #arXiv260522516v1 #AstrophysicsOfGalaxies #blazars #cosmicShear #cosmologicalSimulations #CosmologyAndNonGalacticAstrophysics #DarkEnergy #DarkEnergySpectroscopicInstrument #DarkEnergySurvey #DiamondOpenAccess #DiamondOpenAccessPublishing #galaxyClustering #HighEnergyAstrophysicalPhenomena #InstrumentationAndMethodsForAstrophysics #kineticSunyaevZeDovichEffect #LOFAR #OpenAccess #OpenAccessPublishing #PointSpreadFunction #pulsars #quasars #radioAstronomy #stackedImages #SunyaevZeDovichEffect #supernova #supernovae #Tomography #VeraCRubinObservatory #VeryLargeArray #weakGravitationalLensing
In the DarkMay 9

Weekly Update from the Open Journal of Astrophysics – 09/05/2026

It’s Saturday once again, so time for another update of activity at the Open Journal of Astrophysics. Since the last update we have published a further five papers, bringing the number in Volume 9 (2026) to 99 and the total so far published by OJAp up to 547. We didn’t quite make it to a hundred for the year last week, but will do so with the next paper.

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 “Formation of Close Binaries through Massive Black Hole Perturbations and Chaotic Tides” by Howard Hao-Tse Huang and Wenbin Lu (University of California at Berkeley, USA). This one was published on Wednesday 6th May 2026 in the folder Astrophysics of Galaxies. The paper presents a model of massive black hole-binary systems, showing that repeated tidal interactions can lead to the creation of hyper-velocity stars and other nuclear transients.

The overlay for this paper is here

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

https://fediscience.org/@OJ_Astro/116526323790020433

The second paper for this week, also Wednesday 6th May, but in the folder Cosmology and Nongalactic Astrophysics is “Detection of supernova magnitude fluctuations induced by large-scale structure” by Andrew Nguyen (Swinburne Institute of Technology, Australia) and 58 others based all around the world. This study uses supernovae and galaxy velocities to measure the universe’s structure growth rate, confirming the Planck LambdaCDM model prediction. The methodology is validated and shows potential for future research.

The overlay for this one is here:

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

https://fediscience.org/@OJ_Astro/116526449130876366

Next one up, the third paper of the week, also published on Wednesday 6th May in the folder Cosmology and Nongalactic Astrophysics is “Comparing cosmic shear nulling methods for Stage-IV surveys” by Naomi Clare Robertson and Alex Hall (University of Edinburgh, UK). This study compares three strategies for reducing baryon feedback impact on cosmic shear measurements. All methods effectively mitigate bias, with varying degrees of efficiency and information preservation.

The overlay for this one is here:

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

https://fediscience.org/@OJ_Astro/116526251813375105

The fourth paper this week, published on Thursday May 7th, is “Egent: An Autonomous Agent for Equivalent Width Measurement” by Yuan-Sen Ting & Serat Mahmud Saad (Ohio State University, USA), Fan Liu (National Astronomical Observatories, Beijing, China), and Yuting Shen (Georgia Institute of Technology, USA). Egent is an autonomous agent that combines multi-Voigt profile fitting with large language model visual inspection for efficient, automated analysis of raw flux spectra, validated against expert measurements. This one is in the folder Instrumentation and Methods for Astrophysics. The associated software can be found here.

The overlay is here:

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

https://fediscience.org/@OJ_Astro/116531924397498394

The fifth and final article of this week was published on Friday 8th May in the folder Astrophysics of Galaxies. The title is “DiffstarPop: A generative physical model of galaxy star formation history” and it is by Alex Alarcon (Institute of Space Sciences, Barcelona, Spain), Andrew P. Hearin , Matthew R. Becker & Gillian Beltz-Mohrmann (Argonne National Laborarory, USA), and Andrew Benson & Sachi Weerasooriya (Carnegie Observatories, USA). DiffstarPop is a model that accurately and rapidly reproduces statistical distributions of galaxy star formation histories (SFH), using parameters related to galaxy formation physics.

The overlay is here:

You can find the authorized version of this paper on arXiv here and the Fediverse announcement is here:

https://fediscience.org/@OJ_Astro/116537709130989142

Here endeth this week’s update. There shall be another next Saturday.

P.S. Just a reminder that, thanks to the efforts of a member of our Editorial Board, the Open Journal of Astrophysics now has a Wikipedia page.

#arXiv251007673v2 #arXiv251027604v3 #arXiv251111965v2 #arXiv251201270v2 #arXiv251215604v2 #AstrophysicsOfGalaxies #BaryonicFeedback #blackHoleBinaries #cosmicShear #CosmologyAndNonGalacticAstrophysics #DiamondOpenAccess #DiamondOpenAccessPublishing #Egent #EquivalentWidth #galaxyEvolution #hyperVelocityStars #InstrumentationAndMethodsForAstrophysics #nuclearTransients #OpenAccess #OpenAccessPublishing #peculiarVelocities #supernovae #VoigtProfiles #weakGravitationalLensing
In the DarkMay 2

Weekly Update from the Open Journal of Astrophysics – 02/05/2026

Here we are, on schedule, with another update of activity at the Open Journal of Astrophysics. Since the last update we have published a further seven papers, bringing the number in Volume 9 (2026) to 94 and the total so far published by OJAp up to 542. I checked the corresponding update for last year (on 3rd May 2025), and we’ve had an increase from 54 to 94 in papers published (about 74%) between the first four months of 2025 and the first four months of 2026.

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 “DESI-DR1 3 × 2-pt analysis: consistent cosmology across weak lensing surveys” by Anna Porredon (CIEMAT, Madrid, Spain) and 72 others (DESI Colllaboration). This paper was published on Tuesday 28th April in the folder Cosmology and Nongalactic Astrophysics. This paper presents a joint cosmological analysis of galaxy clustering and gravitational lensing observations, providing consistent constraints on cosmological parameters. The analysis also introduces a new blinding procedure to prevent confirmation bias. See this post for news of an important DESI milestone.

The overlay for this paper is here

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

https://fediscience.org/@OJ_Astro/116480407578621011

The second paper for this week, also published on Tuesday 28th April but in the folder High-Energy Astrophysical Phenomena is “Masers and Broad-Line Mapping Favor Magnetically-Dominated AGN Accretion Disks” by Philip F. Hopkins (Caltech, USA), Dalya Baron (Stanford U., USA) and Joanna M. Piotrowska (Caltech). This one presents a new constraint on supermassive black hole accretion disks physics, suggesting that outer regions are likely in a ‘hyper-magnetized’ state, as thermal or radiation pressure models appear inconsistent.

The overlay for this one is here:

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

https://fediscience.org/@OJ_Astro/116480505354195181

Next one up, the third paper of the week, is “Galaxy mergers and disk angular momentum evolution: stellar halos as a critical test” by Eric F. Bell (U. Michigan, Ann Arbor, USA), Richard D’Souza (Vatican Observatory), Monica Valluri & Katya Gozman (U. Michigan). This was published on Wednesday 29th April in the folder Astrophysics of Galaxies. The paper argues that satellite accretion impacts the angular momentum evolution of galaxies, often causing significant reorientation. This process is detectable in Milky Way-mass galaxies so the idea is testable observationally.

The overlay for this one is here:

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

https://fediscience.org/@OJ_Astro/116486649450860283

The fourth paper this week, published on Thursday April 30th, is “Time-Dilation Methods for Extreme Multiscale Timestepping Problems” by Philip F. Hopkins and Elias R. Most (Caltech, USA). This paper is in the folder Instrumentation and Methods for Astrophysics: it presents a new method for astrophysical simulations that modulates time evolution with a variable dilation/stretch factor, improving efficiency and accuracy in modeling processes across different scales.

The overlay is here:

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

https://fediscience.org/@OJ_Astro/116492226856595031

The fifth article of this week was also published on Thursday 30th April, but in the folder Astrophysics of Galaxies. The title is “Cosmic Rays on Galaxy Scales: Progress and Pitfalls for CR-MHD Dynamical Models” and the author is Philip F. Hopkins (Caltech, USA) who has three papers featured this week. The paper presents an overview of cosmic ray (CR) modeling, highlighting its influence on galactic physics and star formation. It addresses previous modeling errors and presents new methods for full-spectrum dynamics.

The overlay is here:

You can find the authorized version of this paper on arXiv here and the Fediverse announcement is here:

https://fediscience.org/@OJ_Astro/116492282488422075

The sixth paper of the week is “Baryonification III: An accurate analytical model for the dispersion measure probability density function of fast radio bursts” by MohammadReza Torkamani (Universität Bonn, Germany) and 8 others based in Germany, Switzerland, UK and Sweden. This article was also published on Thursday April 30th in the folder Cosmology and Nongalactic Astrophysics. It presents a framework for predicting dispersion measures of fast radio bursts using the baryonification model, providing a cost-effective alternative to hydrodynamical simulations. The model’s accuracy is validated through full numerical simulations. The overlay is here:

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

https://fediscience.org/@OJ_Astro/116492403170125062

Seventh and finally for this week we have “The stellar and dark matter distributions in early-type galaxies measured by stacked weak gravitational lensing” by Momoka Fujikawa and Masamune Oguri (Chiba University, Japan). This study uses weak gravitational lensing to investigate stellar mass and dark matter density in red galaxies, suggesting a stronger feedback effect than current simulations predict. This was published on Friday 1st May 2026 in the folder Astrophysics of Galaxies. The overlay is here:

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

https://fediscience.org/@OJ_Astro/116497987401632687

And that concludes this week’s update. I’ll do another one at the end of next week. Will Vol. 9 have reached a hundred by then?

P.S. Just a reminder that, thanks to the efforts of a member of our Editorial Board, the Open Journal of Astrophysics now has a Wikipedia page.

#32PtAnalysis #ActiveGalacticNuclei #AGN #arXiv250907104v2 #arXiv251009756v2 #arXiv251209342v2 #arXiv251215960v3 #arXiv260106253v2 #arXiv260118784v2 #arXiv260424965v1 #AstrophysicsOfGalaxies #baryonification #ComputationalAstrophysics #cosmicRays #CosmologyAndNonGalacticAstrophysics #DarkEnergySpectroscopicInstrument #DESI #DiamondOpenAccess #DiamondOpenAccessPublishing #DispersionMeasures #fastRadioBursts #galacticCosmicRays #galaxyEvolution #galaxyFormation #galaxyMergers #HighEnergyAstrophysicalPhenomena #InstrumentationAndMethodsForAstrophysics #magnetohydrodynamics #masers #MilkyWay #OpenAccess #OpenAccessPublishing #SolarAndStellarAstrophysics #SolarCorona #supermassiveBlackHoles #VeraCRubinObservatory #weakGravitationalLensing #wikipedia
In the DarkApr 4

Weekly Update from the Open Journal of Astrophysics – 04/04/2026

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.

The first paper to report this week is “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). This paper was published on Tuesday March 31st in the folder Cosmology and Nongalactic Astrophysics.

The overlay is here:

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

https://fediscience.org/@OJ_Astro/116322295318460212

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:

https://fediscience.org/@OJ_Astro/116322348900996677

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:

https://fediscience.org/@OJ_Astro/116322403314492269

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:

https://fediscience.org/@OJ_Astro/116328145696781139

And that concludes the update for this week. I’ll do another next week, but I’m expecting a fairly low number of papers owing to the Easter vacation.

#3x2ptAnalysis #arXiv250713317v2 #arXiv250918266v2 #arXiv251005539v2 #arXiv260204977v2 #AstrophysicsOfGalaxies #CosmologyAndNonGalacticAstrophysics #DESI #DiamondOpenAccess #DiamondOpenAccessPublishing #diffHODIA #dust #dustGrains #galaxyFormation #haloModels #InstrumentationAndMethodsForAstrophysics #intrinsicAlignments #MilkyWay #OpenAccess #OpenAccessPublishing #supernovae #weakGravitationalLensing
In the DarkJan 17

Weekly Update from the Open Journal of Astrophysics – 17/01/2026

It’s Saturday once more so time for another update of activity at the Open Journal of Astrophysics. Since the last update we have published seven papers, bringing the number in Volume 9 (2026) to 11 and the total so far published by OJAp up to 459. This week has been quite busy; for only the second time in recorded history we published at least one paper each working day.

I will continue to include the announcements 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.

The first three papers this week were all published on Monday January 12th in the folder Astrophysics of Galaxies.

The first paper to report this week is “Rotational Kinematics in the Globular Cluster System of M31: Insights from Bayesian Inference” by Yuan (Cher) Li & Brendon J. Brewer (U. Auckland, New Zealand), Geraint F. Lewis (U. Sydney, Australia) and Dougal Mackey (independent researcher, Australia). This study uses Bayesian modelling to explore the kinematics of globular clusters in the Andromeda Galaxy, revealing distinct rotation patterns that suggest different subgroups were added at separate times.

The overlay is here:

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

https://fediscience.org/@OJ_Astro/115881522738421378

The second paper is “DESI Data Release 1: Stellar Catalogue” by Sergey Koposov (U. Edinburgh, UK) and an international cast of 67 other authors. This paper introduces and describes the stellar Value-Added Catalogue (VAC) based on DESI Data Release 1, providing measurements for over 4 million stars, including radial velocity, abundance, and stellar parameters.

The overlay for this one is here:

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

https://fediscience.org/@OJ_Astro/115881586884465975

Next we have “On the origins of oxygen: ALMA and JWST characterise the multi-phase, metal-enriched, star-bursting medium within a ‘normal’ z>11 galaxy” by Joris Witstok (Cosmic Dawn Centre, Copenhagen, Denmark) and 37 others in locations dotted around the world. This paper presents new ALMA observations of the JADES-GS-z11-0 galaxy confirm the presence of the [O III] 88 µm line, suggesting it consists of two low-mass components undergoing star formation and enriched in metals.

The overlay is here:

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

https://fediscience.org/@OJ_Astro/115881659633273777

The fourth paper this week is also in the folder Astrophysics of Galaxies. but was published on Tuesday 13th January. It is entitled “Accelerated calibration of semi-analytic galaxy formation models” by Andrew Robertson and Andrew Benson (Carnegie Observatories, USA). This paper presents a faster calibration framework for galaxy formation models, using fewer simulations for each evaluation. However, the model shows discrepancies suggesting the model needs to be made more flexible.

The overlay is here:

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

https://fediscience.org/@OJ_Astro/115887131054018297

Next one up, published on Wednesday 14th January in the folder Cosmology and Nongalactic Astrophysics, is “Constraints from CMB lensing tomography with projected bispectra” by Lea Harscouet & David Alonso (U. Oxford), UK), Andrina Nicola (U. Manchester, UK) and Anže Slosar (Brookhaven National Laboratory, USA). This study presents angular power spectra and bispectra of DESI luminous red galaxies, finding that the galaxy bispectrum can constrain the amplitude of matter fluctuations and the non-relativistic matter fraction. The overlay is here:

You can find the officially accepted paper on arXiv here and the Mastodon announcement here:

https://fediscience.org/@OJ_Astro/115893813149036197

The sixth paper this week is “Universal numerical convergence criteria for subhalo tidal evolution” by Barry T. Chiang & Frank C. van den Bosch (Yale U., USA) and Hsi-Yu Schive (National Taiwan University, Taiwan). This was published on Thursday 15th January in the folder Cosmology and Nongalactic Astrophysics; it presents an analysis of a simulation suite that addresses the ‘overmerging’ problem in cosmological simulations of dark matter subhalos, showing that up to 50% of halos in state-of-the art simulations are unresolved. The overlay is here:

The final accepted version of this paper can be found on arXiv here. The Mastodon announcement follows:

https://fediscience.org/@OJ_Astro/115898339098021093

Finally for this week we have “Detectability of dark matter subhalo impacts in Milky Way stellar streams” by Junyang Lu , Tongyan Lin & Mukul Sholapurkar (UCSD, USA) and Ana Bonaca (Carnegie Observatories, USA). This was published on Friday 16th January (i.e. yesterday) in the folder Astrophysics of Galaxies. The study develops a method to estimate the minimum detectable dark matter subhalo mass in stellar streams, ranking them by sensitivity and identifying promising lines for further research.

The overlay is here:

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

https://fediscience.org/@OJ_Astro/115904083514716420

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

#ALMA #arXiv250207781v3 #arXiv250514787v3 #arXiv250707968v2 #arXiv250722888v4 #arXiv250900143v2 #arXiv251026901v2 #arXiv260105380v2 #AstrophysicsOfGalaxies #BayesianMethods #CosmologyAndNonGalacticAstrophysics #DarkEnergySurvey #darkMatter #DES #DiamondOpenAccess #DiamondOpenAccessPublishing #galaxyFormation #JWST #M31 #MilkyWay #OpenAccess #OpenAccessPublishing #OpenJournalOfAstrophysics #Oxygen #semiAnalyticModels #subhalos #TheOpenJournalOfAstrophysics #Tomography #weakGravitationalLensing

In the DarkJan 10

Weekly Update from the Open Journal of Astrophysics – 10/01/2026

Welcome to the first proper update for 2026 from the Open Journal of Astrophysics. The New Year brings us to Volume 9. In many countries, especially in Europe, Christmas is celebrated on January 6th so this week was also affected by the holiday season. Nevertheless, since the last update we have published four papers, bringing the number in Volume 9 (2026) to 4 and the total so far published by OJAp up to 452.

The first paper this week (and of course the first of 2026) is “A targeted, parallax-based search for Planet Nine” by Hector Socas-Navarro and Ignacio Trujillo (both of the Instituto de Astrofísica de Canaria, Spain). This article describes a targeted search for the hypothesized Planet Nine in the outer solar system, using parallax position shifts. No credible candidates were found within the observed field. It was published on Tuesday January 6th in the folder Earth and Planetary Astrophysics. The overlay is here:

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

https://fediscience.org/@OJ_Astro/115847068676034973

The second paper is “Going beyond S8: fast inference of the matter power spectrum from weak-lensing surveys” by Cyrille Doux (Université Grenoble Alpes, France) and Tanvi Karwal (U. Chicago, USA). This was published on Wednesday January 7th in the folder Cosmology and Nongalactic Astrophysics and it presents a new framework to extract the scale-dependent matter power spectrum from cosmic shear and CMB lensing measurements, revealing a consistent suppression in the matter power spectrum in galaxy-lensing. The overlay is here:

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

https://fediscience.org/@OJ_Astro/115853112748106265

Next we have “Constraining the Stellar-to-Halo Mass Relation with Galaxy Clustering and Weak Lensing from DES Year 3 Data” which is led by G. Zacharegkas et al. (Argonne National Laboratory, USA) and has 102 other authors too numerous to list by name from many institutions around the world again too numerous to list by name. It presents a framework to analyze the relationship between a galaxy’s stellar mass and its dark matter halo mass, using data from the Dark Energy Survey. The findings align with previous results. This paper was published on Thursday January 8th in the folder Astrophysics of Galaxies. The overlay is here:

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

https://fediscience.org/@OJ_Astro/115858972601709198

Finally for this week we have “Distance measurements from the internal dynamics of globular clusters: Application to the Sombrero galaxy (M 104)” by Katja Fahrion (University of Vienna, Austria) and 9 others based in Spain, Australia, UK, USA, Brazil, Germany and Switzerland. This was published on Friday 9th January (yesterday) in the folder Astrophysics of Galaxies. This study uses the globular cluster velocity dispersion method to measure the distance to the Sombrero galaxy, finding it to be approximately 9.0 Mpc away. The overlay is here:

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

https://fediscience.org/@OJ_Astro/115864438724623861

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

#arXiv250405473v2 #arXiv250616434v3 #arXiv250622367v3 #AstrophysicsOfGalaxies #CosmologyAndNonGalacticAstrophysics #DarkEnergySurvey #DES #DiamondOpenAccess #DiamondOpenAccessPublishing #EarthAndPlanetaryAstrophysics #galaxyClustering #galaxyHalo #OpenAccess #OpenAccessPublishing #OpenJournalOfAstrophysics #Planet9 #PowerSpectrum #StellarMass #TheOpenJournalOfAstrophysics #weakGravitationalLensing

In the DarkDec 20

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

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

@[email protected]

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

https://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

@[email protected]

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)

https://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.

#arXiv250416076v3 #arXiv251009480v2 #AstrophysicsOfGalaxies #CosmologyAndNonGalacticAstrophysics #DiamondOpenAccess #DiamondOpenAccessPublishing #gravitationalInfall #InterstellarMedium #intrinsicAlignments #OpenAccess #OpenJournalOfAstrophysics #RedshiftSpaceDistortions #starFormation #starFormingClouds #TheOpenJournalOfAstrophysics #weakGravitationalLensing

In the DarkOct 25, 2025

Weekly Update from the Open Journal of Astrophysics – 25/10/2025

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.



  • “The DECADE cosmic shear project I: A new weak lensing shape catalog of 107 million galaxies“, accepted version on arXiv here.
  • “The DECADE cosmic shear project II: photometric redshift calibration of the source galaxy sample“, accepted version on arXiv here.
  • “The DECADE cosmic shear project III: validation of analysis pipeline using spatially inhomogeneous data“, accepted version on arXiv here.
  • “The DECADE cosmic shear project IV: cosmological constraints from 107 million galaxies across 5,400 deg2 of the sky“, accepted version on arXiv here.

    • The fediverse announcements follow:

    Open Journal of Astrophysics

    @[email protected]

    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)

    https://doi.org/10.33232/001c.146158

    October 22, 2025, 12:42 pm 2 boosts 0 favorites

    Open Journal of Astrophysics

    @[email protected]

    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)

    https://doi.org/10.33232/001c.146159

    October 22, 2025, 1:07 pm 2 boosts 0 favorites

    Open Journal of Astrophysics

    @[email protected]

    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)

    https://doi.org/10.33232/001c.146160

    October 22, 2025, 1:57 pm 1 boosts 0 favorites

    Open Journal of Astrophysics

    @[email protected]

    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)

    https://doi.org/10.33232/001c.146161

    October 22, 2025, 2:47 pm 1 boosts 0 favorites

     

    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:

    Open Journal of Astrophysics

    @[email protected]

    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)

    https://doi.org/10.33232/001c.146033

    October 23, 2025, 8:28 am 1 boosts 0 favorites

     

    That concludes the papers for this week. With one week to go and our total at 396, I still think we might reach the 400 total by the end of October.

    #ACT #arXiv250217674v2 #arXiv250217675v2 #arXiv250217676v2 #arXiv250217677v2 #arXiv250820904v2 #AtacamaCosmologyTelescope #cosmicShear #Cosmology #CosmologyAndNonGalacticAstrophysics #DarkEnergySpectroscopicInstrument #DECADECosmicShearProject #DESI #DiamondOpenAccess #DiamondOpenAccessPublishing #galaxyClustering #OpenAccess #OpenJournalOfAstrophysics #TheOpenJournalOfAstrophysics #thermalSunyaevZeldovichEffect #weakGravitationalLensing

    Weekly Update from the Open Journal of Astrophysics – 18/10/2025

    Since the last update we have published four more papers, which brings the number in Volume 8 (2025) up to 156, and the total so far published by OJAp up to 391.

    In the Dark