NOIRLab image of the week
The Cosmic Steering Wheel NGC 1269
Credit: Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA; Image processing: R. Colombari & M. Zamani (NSF NOIRLab)
https://noirlab.edu/public/images/iotw2608a/
#NOIRLab #NGC1269 #galaxy #galaxies #astrodon #astrophysics #astronomy #science #photography #DarkEnergySurvey
Más de 400 astrofísicos y científicos combinan cuatro métodos cosmológicos para crear el mapa más preciso de la evolución del universo y la energía oscura.
#DarkEnergySurvey #ExpansiónUniverso #EnergíaOscura #Astronomía #Tutiempo #NASA
https://www.tutiempo.net/noticias/dark-energy-survey-redefine-expansion-universo.html
Dark Energy Survey Year Y6 Results Day!
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 Greeland). 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.
A number of DES Y6 papers already published – including several in the Open Journal of Astrophysics – are listed here.
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.
#Cosmology #DarkEnergy #DarkEnergySpectroscopicInstrument #DarkEnergySurvey #DES #DESYear6 #DESI
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
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
Weekly Update from the Open Journal of Astrophysics – 27/09/2025
It’s Saturday again, so it’s time for a summary of the week’s new papers at the Open Journal of Astrophysics. Since the last update we have published five new papers, which brings the number in Volume 8 (2025) up to 141, and the total so far published by OJAp up to 376.
The first paper to report this week is “The Bispectrum of Intrinsic Alignments: Theory Modelling and Forecasts for Stage IV Galaxy Surveys” by Thomas Bakx (Utrecht U., NL), Alexander Eggemeier (U. Bonn, DE), Toshiki Kurita (MPA Garching, DE), Nora Elisa Chisari (Leiden U., NL) and Zvonimir Vlah (Ruđer Bošković Institute, Croatia). This paper was published on Monday 22nd September 2025 in the folder Cosmology and NonGalactic Astrophysics. It studies the bispectrum of intrinsic galaxy alignments, a possible source of systematic errors in extracting cosmological information from the analysis of weak lensing surveys.
The overlay is here:
You can make this larger by clicking on it. The officially accepted version of this paper can be found on the arXiv here.
The second paper this week, published on Tuesday 23rd September 2025 is “Reanalysis of Stage-III cosmic shear surveys: A comprehensive study of shear diagnostic tests” by Jazmine Jefferson (University of Chicago, USA) and 13 others for the LSST Dark Energy Science Collaboration. It is also in the folder Cosmology and NonGalactic Astrophysics; it describes diagnostic tests on three public shear catalogs (KiDS-1000, Year 3 DES-Y3 s, and Year 3 HSC-Y3); not all the surveys pass all the tests.
The corresponding overlay is here:
You can find the officially accepted version on arXiv here.
The third one this week, published on Wednesday 24th September 2025 in the folder Astrophysics of Galaxies, is “Is feedback-free star formation possible?” by Andrea Ferrara, Daniele Manzoni, and Evangelia Ntormousi (all of the Scuola Normale Superiore, Pisa, Italy). This paper presents an argument that Lyman-alpha radiation pressure strongly limits star formation efficiency, even at solar metallicities, so that a feedback-free star formation phase is not possible without feedback. The overlay is here:
You can find the officially-accepted version on arXiv here.
Next we have “Microphysical Regulation of Non-Ideal MHD in Weakly-Ionized Systems: Does the Hall Effect Matter?” by Philip F. Hopkins (Caltech, USA), Jonathan Squire (U. Otago, New Zeland), Raphael Skalidis (Caltech) and Nadine H. Soliman (Caltech). This was also published on Wednesday 24th September 2025, but in the folder Earth and Planetary Astrophysics. It presents an improved treatment of non-ideal effects in magnetohydrodynamics, particularly the Hall effect, and a discussion of the implications for weakly-ionized astrophysical systems.
The corresponding overlay is here:
You can find the officially accepted version of this one on arXiv here.
The fifth, and last, one for this week is “The Local Volume Database: a library of the observed properties of nearby dwarf galaxies and star clusters” by Andrew B. Pace (University of Virginia, USA). This one was published on Friday 26th September (i.e. yesterday) in the folder Astrophysics of Galaxies. It presents a catalogue of positional, structural, kinematic, chemical, and dynamical parameters for dwarf galaxies and star clusters in the Local Volume. The overlay is here:
You can find the officially-accepted version of this paper on arxiv here.
And that concludes the report for this week. I’ll post another update next Saturday.
#arXiv240506026v2 #arXiv241107424v2 #arXiv250410009v2 #arXiv250503964v3 #arXiv250902566v2 #AstrophysicsOfGalaxies #bispectrum #cosmicShear #CosmologyAndNonGalacticAstrophysics #DarkEnergySurvey #DiamondOpenAccessPublishing #dwarfGalaxies #EarthAndPlanetaryAstrophysics #feedback #HallEffect #intrinsicAlignments #KIDS #LocalGroup #magnetohydrodynamics #OpenAccessPublishing #StarClusters #starFormation #weakGravitationalLensing
Weekly Update from the Open Journal of Astrophysics – 31/05/2025
Once again it’s time for the weekly Saturday morning update of papers published at the Open Journal of Astrophysics. Since the last update we have published five new papers, which brings the number in Volume 8 (2025) up to 67; the total so far published by OJAp has passed the 300 mark and is now up to 302. If we keep up at the same rate for the rest of the year as we did for the first five months now completed, we will publish around 160 papers altogether in 2025.
In chronological order of publication, the five 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 “Which is the most eccentric binary known? Insights from the 2023/4 pericenter passages of Zeta Boötis and Eta Ophiuchi” by Idel Waisberg, Ygal Klein and Boaz Katz (Weizmann Institute of Science, Israel). This is a report of interferometric observations of two very eccentric binary star systems, published on Tuesday 27th May 2025 in the folder Solar and Stellar Astrophysics. The overlay is here:
You can read the final accepted version on arXiv here.
The second paper to report is “On the full non-Gaussian Surprise statistic and the cosmological concordance between DESI, SDSS and Pantheon+” by Pedro Riba Mello & Miguel Quartin (Universidade Federal do Rio de Janeiro, Brazil), and Bjoern Malte Schaefer & Benedikt Schosser (Heidelberg, Germany). This paper is in the folder Cosmology and NonGalactic Astrophysics and was published on Tuesday 27th May 2025. The paper presents an application of the “Surprise Statistic”, based on the Kullback-Leibler divergence, as a measure of the difference between results inferred from different data sets.
The overlay is here:
You can find the officially-accepted version of the paper on arXiv here.
The third paper we published last week, and our 300th overall, is “Cosmic Ray Feedback in Massive Halos: Implications for the Distribution of Baryons” by Eliot Quataert (Princeton, USA) and Philip F. Hopkins (Caltech, USA). This was published on Thursday 29th May in the folder Cosmology and NonGalactic Astrophysics. The paper discusses the effects of cosmic rays produced by massive black holes on the structure of the baryonic component of galaxies and how these might affect cosmological parameter estimation. The overlay is here:
You can read the officially accepted version of this paper on arXiv here.
The next one to report is “Mixing neutron star material into the jets in the common envelope jets supernova r-process scenario” by Noam Soker (Technion, Israel). This was published on Thursday 27th May in the folder High-Energy Astrophysical Phenomena; it presents a discussion of the chemical enrichment of an evolved star consequent upon its ingestion of a neutron star.
The overlay is here:
You can find the officially accepted version on arXiv here.
Last, but by no means least, for this week we have “Dark Energy Survey Year 6 Results: Synthetic-source Injection Across the Full Survey Using Balrog” by Dhayaa Anbajagane (Kavli Institute, Chicago) et al. (81 authors) on behalf of the Dark Energy Survey Collaboration. It was also published on Thursday 27th May 2025, but in the folder Cosmology and NonGalactic Astrophysics. It is about testing the Dark Energy Survey analysis pipeline using synthetic sources.
The overlay is here:
You can find the officially accepted version on arXiv here.
That’s all the papers for this week. I’ll post another update next weekend.
#arXiv240808385v2 #arXiv250105683v3 #arXiv250201753v2 #arXiv250202411v2 #arXiv250417858v2 #binaryStars #CosmologyAndNonGalacticAstrophysics #DarkEnergySurvey #DiamondOpenAccess #DiamondOpenAccessPublishing #HighEnergyAstrophysicalPhenomena #neutronStar #OpenJournalOfAstrophysics #rProcess #SolarAndStellarAstrophysics #TheOpenJournalOfAstrophysics
The Dark Energy Survey (DES) recently released the final results of its two principal probes of the expansion history: Type Ia Supernovae (SNe) and Baryonic Acoustic Oscillations (BAO). In this paper, we explore the cosmological implications of these data in combination with external Cosmic Microwave Background (CMB), Big Bang Nucleosynthesis (BBN), and age-of-the-Universe information. The BAO measurement, which is $\sim2σ$ away from Planck's $Λ$CDM predictions, pushes for low values of $Ω_{\rm m}$ compared to Planck, in contrast to SN which prefers a higher value than Planck. We identify several tensions among datasets in the $Λ$CDM model that cannot be resolved by including either curvature ($kΛ$CDM) or a constant dark energy equation of state ($w$CDM). By combining BAO+SN+CMB despite these mild tensions, we obtain $Ω_k=-5.5^{+4.6}_{-4.2}\times10^{-3}$ in $kΛ$CDM, and $w=-0.948^{+0.028}_{-0.027}$ in $w$CDM. If we open the parameter space to $w_0$$w_a$CDM\$ (where the equation of state of dark energy varies as $w(a)=w_0+(1-a)w_a$), all the datasets are mutually more compatible, and we find concordance in the $[w_0>-1,w_a<0]$ quadrant. For DES BAO and SN in combination with Planck-CMB, we find a $3.2σ$ deviation from $Λ$CDM, with $w_0=-0.673^{+0.098}_{-0.097}$, $w_a = -1.37^{+0.51}_{-0.50}$, a Hubble constant of $H_0=67.81^{+0.96}_{-0.86}$km s$^{-1}$Mpc$^{-1}$, and an abundance of matter of $Ω_{\rm m}=0.3109^{+0.0086}_{-0.0099}$. For the combination of all the background cosmological probes considered (including CMB $θ_\star$), we still find a deviation of $2.8σ$ from $Λ$CDMin the $w_0-w_a$ plane. Assuming a minimal neutrino mass, this work provides further evidence for non-$Λ$CDM physics or systematics, which is consistent with recent claims in support of evolving dark energy.
Weekly Update at the Open Journal of Astrophysics – 15/03/2025
The Ideas of March are come, so it’s time for another update of papers published at the Open Journal of Astrophysics. Since the last update we have published two papers, which brings the number in Volume 8 (2025) up to 27 and the total so far published by OJAp up to 262.
The first paper to report is “Dark Energy Survey Year 6 Results: Point-Spread Function Modeling” by Theo Schutt and 59 others distributed around the world, on behalf of the DES Collaboration. It was published on Wednesday March 12th 2025 in the folder Cosmology and NonGalactic Astrophysics. It discusses the improvements made in modelling the Point Spread Function (PSF) for weak lensing measurements in the latest Dark Energy Survey (6-year) data and prospects for the future.
Here is the overlay, which you can click on to make larger if you wish:
You can read the officially accepted version of this paper on arXiv here.
The other paper published this week is “Exploring Symbolic Regression and Genetic Algorithms for Astronomical Object Classification” by Fabio Ricardo Llorella (Universidad Internacional de la Rioja, Spain) & José Antonio Cebrian (Universidad Laboral de Córdoba, Spain), which came out on Thursday 13th March. This one is in the folder marked Astrophysics of Galaxies and it discusses the classification of astronomical objects in the Sloan Digital Sky Survey SDSS-17 dataset using a combination of Symbolic Regressiion and Genetic Algorithms.
The overlay can be seen here:
You can find the “final” version on arXiv here.
That’s it for this week. I’ll have more papers to report next Saturday.
#arXiv250105781v2 #arXiv250309220v1 #AstronomicalObjectClassification #AstrophysicsOfGalaxies #CosmologyAndNonGalacticAstrophysics #DarkEnergySurvey #DES #DiamondOpenAccess #GeneticAlgorithms #OpenAccessPublishing #SloanDigitalSkySurvey #SymbolicRegression #TheOpenJournalOfAstrophysics #weakGravitationalLensing
[Einstein's theory and #observation data] Researchers have compared #DarkEnergySurvey data with predictions from Einstein's theory of #GeneralRelativity ... and discovered some #incompatibility ...
“We have discovered that very far in the past, 6 and 7 billion years ago, the depth of the #GravitationalSinks is completely compatible with Einstein's predictions. On the other hand, in the period closer to today, 3.5 and 5 billion years ago, they are a little shallower than predicted by Einstein”, reveals Isaac Tutusaus, assistant astronomer at IRAP / Université Paul Sabatier Toulouse III.
Is the slowdown in the growth of gravitational sinks linked to the acceleration of the #expansion of our #Universe? The answer will undoubtedly be found in a few years' time, thanks to more numerous and more precise data from the @ec_euclid mission.
Details+: https://www.irap.omp.eu/en/2024/11/einsteins-equations-collide-with-the-mysteries-of-the-universe/
Daniel Pomarède
Tutiempo.net
In the Dark
Daniel Fischer
IRAP