#baryonacousticoscillations — Public Fediverse posts

https://www.europesays.com/ie/622290/ New cosmology model finds that dark matter doesn’t exist #Astronomy #BaryonAcousticOscillations #CCC+TLModel #CosmicMicrowaveBackground #cosmology #CovaryingCouplingConstants #DarkEnergy #DarkMatter #Éire #GalaxyFormation #IE #Ireland #JamesWebbSpaceTelescope #Physics #RajendraGupta #redshift #Research #Science #SpaceNews #TiredLightTheory #UniverseAge #UniverseWithoutDarkMatter #UniversityOfOttawa

Weekly Update from the Open Journal of Astrophysics 04/07/2026

It’s Saturday 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 seven papers, bringing the number in Volume 9 (2026) to 136 and the total so far published by OJAp up to 584.

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 29th June, is “Analysis and implications of the spatio-spectral morphology of the Fermi Bubbles” by Ami Tank (Indian Institute of Technology) and Roland Crocker & Mark R. Krumholz (Australian National University). Published in the folder High-Energy Astrophysical Phenomena, this paper presents an analysis of the gamma-ray structures of Fermi Bubbles in the Milky Way using a decade of data. The research suggests either hadronic or leptonic processes can explain the data.

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/116831750056897536

The second paper for this week, also published on Monday 29th June, but in the folder Cosmology and Nongalactic Astrophysics, is “A first measurement of baryonic feedback with Fast Radio Bursts” by Robert Reischke (Universität Bonn, Germany) and Steffen Hagstotz (Ludwig-Maximilians Universität München, Germany). This paper argues that Fast Radio Bursts (FRBs) provide a new method to trace baryon distribution and feedback in the cosmos, offering insights into matter distribution and rejecting no-feedback scenarios with high confidence.

The overlay looks like this:

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

https://fediscience.org/@OJ_Astro/116831826841996152

The third paper of the week, published on Tuesday 30th June in the folder High-Energy Astrophysical Phenomena, is “Idealized Global Models of Accretion Disks with Strong Toroidal Magnetic Fields” by Minghao Guo & Eliot Quataert (Princeton U., USA), Jonathan Squire (U. Otago, NZ), Philip F. Hopkins (Caltech, USA) and James M. Stone (Princeton). This study uses global magnetohydrodynamic simulations to explore the behavior of idealized accretion disks with strong toroidal magnetic fields, finding that these systems maintain a moderately strong mean azimuthal field.

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/116837655082737919

The fourth paper of the week, published on Tuesday 30th June in the folder High-Energy Astrophysical Phenomena, is “On the effective spin-mass ratio relation of binary black hole mergers that evolved in isolation” by Sambaran Banerjee (Helmholtz-Instituts für Strahlen und Kernphysik, Germany) and Aleksandra Olejak (MPA Garching, Germany). This study explores mechanisms of binary black hole mergers and finds that certain spin and mass ratio trends can be naturally explained by isolated binary evolution. The overlay for this one is here:

You can read the final version of this one on arXiv here and the Mastodon announcement is here:

https://fediscience.org/@OJ_Astro/116837827227415689

The fifth paper of the week, also published on Tuesday 30th June but in the folder Solar and Stellar Astrophysics is “A systematic survey for hypervelocity runaways from thermonuclear supernovae” by Kareem El-Badry (Caltech, USA), and 18 others based in the USA, Germany, Austria and the UK. This paper presents a systematic survey of hypervelocity runaways, resulting from white dwarf explosions in binary systems. The findings suggest a diversity of remnant masses, ages, and heating mechanisms, challenging theoretical models.

The overlay for this one is here:

You can read the final version of this one on arXiv here and the Mastodon announcement is here:

https://fediscience.org/@OJ_Astro/116837896833204693

The sixth and penultimate paper of this week is “Boris and Exponential Integrators in the Theory of Particles Interacting with Magnetic Turbulence” by Andreas Shalchi (U. Manitoba, Canada). This was published on Wednesday 1st July, in the folder Solar and Stellar Astrophysics (it is posted in the plasma physics section of aXiv but cross-listed in solar and stellar astrophysics). The study compares the Rodrigues and Boris integrators in test-particle simulations of charged particles interacting with magnetic fields, finding both methods yield similar results.

The overlay for this one is here:

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

https://fediscience.org/@OJ_Astro/116843121887902595

The seventh and final paper for this week is “Inflation at the End of 2025: Constraints on $r$ and $n_S$ using the Latest CMB and BAO Data” by Lennart Balkenhol (Institut d’Astrophysique de Paris, France) and 12 others based in France, Italy, Switzerland, UK, USA and Australia. This was also published on Wednesday 1st July, in the folder Cosmology and Nongalactic Astrophysics. This study presents constraints on parameters of inflationary models in cosmology, using the latest cosmic microwave background and baryon acoustic oscillation data. The findings help differentiate between inflation models.

The overlay for this one is here:

You can find the final accepted version of this one on arXiv here and the Mastodon announcement is here:

https://fediscience.org/@OJ_Astro/116843339514720727

And that concludes this week’s update. We’re starting to catch up on the backlog generated in June. At just past the halfway point of the year, which is where we are, we’re on 136 papers, which suggests a total around 272 for the year.

New sound proof we’re living in a giant void

Looking up at the night sky, it may seem our cosmic neighborhood is packed full of planets, stars…
#NewsBeep #News #Science #BaryonAcousticOscillations #CA #Canada #cosmicmicrowavebackground #Cosmology #HubbleTension #ScienceandTechnology #Space #TheConversation
https://www.newsbeep.com/ca/44193/

Cosmology Results from DESI

Yesterday evening (10pm Irish Time) saw the release of new results from the Dark Energy Spectroscopic Instrument (DESI), completing a trio of major announcements of cosmological results in the space of two days (the Atacama Cosmology Telescope and the Euclid Q1 release being the others). I didn’t see the DESI press conference but you can read the press release here.

There were no fewer than eight DESI papers on the astro-ph section of the arXiv this morning. Here are the titles with links:

• DESI DR2 Results I: Baryon Acoustic Oscillations from the Lyman Alpha Forest
• DESI DR2 Results II: Measurements of Baryon Acoustic Oscillations and Cosmological Constraints;
• Construction of the Damped Lyα Absorber Catalog for DESI DR2 Lyα BAO;
• Validation of the DESI DR2 Lyα BAO analysis using synthetic datasets;
• Validation of the DESI DR2 Measurements of Baryon Acoustic Oscillations from Galaxies and Quasars;
• Extended Dark Energy analysis using DESI DR2 BAO measurements;
• Constraints on Neutrino Physics from DESI DR2 BAO and DR1 Full Shape;
• Data Release 1 of the Dark Energy Spectroscopic Instrument.

You can see from the titles that the first seven of these relate to the second data release (DR2; three years of data) from DESI; the last one listed here is a description of the first data release (DR1), which is now publicly available.

Obviously there is a lot of information to digest in these papers so here are two members of the DESI collaboration talking with Shaun Hotchkiss on Cosmology Talks about the key messages from the analysis of Baryon Acoustic Oscillations (the BAO in the titles of the new papers):

https://www.youtube.com/watch?v=YiRaDtslycE

A lot has been made in the press coverage of these results about the evidence that the standard cosmological model is incomplete; see, e.g., here. Here are a few comments.

As I see it, taken on their own, the DESI BAO results are broadly consistent with the ΛCDM model as specified by the parameters determined by the Cosmic Microwave Background (CMB) inferred from Planck. Issues do emerge, however, when these results are combined with other data sets. The most intriguing of these arises with the dark energy contribution. 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 of the dark energy ρ 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<0 not that w=-1.

The DESI team allow (w0, wa) to act as free parameters and let the DESI data constrain them, either alone or in combinations with other data sets, finding evidence for departures from the “standard values”. Here’s an example plot:

The DESI data don’t include the standard point (at the intersection of the two dashed lines) but the discrepancy gets worse when other data (such as supernovae and CMB) are folded in, as in this picture. The weight of evidence suggests a dark energy contribution which is decreasing with time.

These results are certainly intriguing, and a lot of credit is due to the DESI collaboration for working so hard to identify and remove possible systematics in the analysis (see the papers above) but what do they tell us about ΛCDM?

My view is that we’ve never known what the dark energy actually is or why it is so large that it represents 70% of the overall energy density of the Universe. The Λ in ΛCDM is really just a place-holder, not there for any compelling physical reason but because it is the simplest way of accounting for the observations. In other words, it’s what it is because of Occam’s Razor and nothing more. As with any working hypothesis, the standard cosmological model will get updated whenever new information comes to light (as it is doing now) and/or if we get new physical insights into the origin of dark energy.

Do the latest observations cast doubt on the standard model? I’d say no. We’re seeing an evolutionary change from “We have no idea what the dark energy is but we think it might be a cosmological constant” to “We still have no idea what the dark energy is but we think it might not be a cosmological constant”.

#baryonAcousticOscillations #cosmologicalConstant #Cosmology #DarkEnergy #DarkEnergySpectroscopicInstrument #OccamSRazor #ShaunHotchkiss

my favorite things

Mars, Encelade, the early universe (for a 10-pages zoom paper by yours truly on baryon acoustic oscillations, following the discovery of Ho'oleilana) are on the cover of the latest issue of l'Astronomie Magazine

#Mars #Enceladus #Cosmology #Astronomy #Astrophysics #Astronomie #Astrophysique #Cosmologie #magazine #AstronomieMagazine #BAO #BaryonAcousticOscillations #science #STEM #Hooleilana #galaxies #scicomm #cover #covers #news

how it started, how it's going

These are the 1st and latest covers of l'Astronomie, the venerable magazine established by Camille Flammarion in 1882. I'm honored to be the author of the feature article of this new issue, on Baryon Acoustic Oscillations.

https://lastronomie.fr/

#Cosmology #Astronomy #Astrophysics #Astronomie #Astrophysique #Cosmologie #magazine #AstronomieMagazine #CamilleFlammarion #BAO #BaryonAcousticOscillations #science #STEM #Hooleilana #galaxies #scicomm #cover #covers

Rencontre avec Ho’oleilana, la nouvelle mégastructure cosmique.

/ Meet Ho'oleilana, the new cosmic mega structure.

✍️ by Valérie Greffoz for Epsiloon Magazine

https://www.epsiloon.com/tous-les-numeros/n39/on_a_vu_une_gigantesque_bulle_pres_de_la_voie_lactee/

#Cosmology #Hooleilana #galaxies #BAO #BaryonAcousticOscillations #CosmicWeb #Cosmicflows #BrentTully #Epsiloon #EpsiloonMag #Astronomy #Astrophysics #Astrodon #space #science #STEM #research #article

Great Nature News Feature article on the recent DESI Survey results on dark energy

With a final quote by Jim Peebles: “I find it very difficult to imagine that ΛCDM is the end of the story. It’s too simple.”

https://www.nature.com/articles/d41586-024-01273-4

#Cosmology #DarkEnergy #ΛCDM #JimPeebles #DESI #survey #DESIsurvey #BAO #BaryonAcousticOscillations #galaxies #astronomy #astrophysics #astrodon #Nature #news #science

DESI 2024 VI - Cosmological Constraints from the Measurements of #BaryonAcousticOscillations: https://arxiv.org/abs/2404.03002 -> First Results from #DESI Make the Most Precise Measurement of Our Expanding #Universe: https://www.physics.utah.edu/news/first-results-from-desi-make-the-most-precise-measurement-of-our-expanding-universe/ and https://newscenter.lbl.gov/2024/04/04/desi-first-results-make-most-precise-measurement-of-expanding-universe/ and https://www.rochester.edu/newscenter/what-is-dark-energy-desi-expanding-universe-600592/ and https://news.ucsc.edu/2024/04/desi-universe-mapped.html and https://kpno.noirlab.edu/news/noirlab2408/ and https://www6.slac.stanford.edu/news/2024-04-04-first-results-desi-make-most-precise-measurement-our-expanding-universe > Scientists decode 'death' of our universe, say it will one day collapse and end with a 'big crunch': https://www.wionews.com/science/scientists-decode-death-of-universe-says-it-will-end-with-a-big-crunch-712135

40000 downloads for the Ho'oleilana paper and still among the ApJ most-read papers. Amazing!

#OpenAccess

https://doi.org/10.3847/1538-4357/aceaf3

#publishing #cosmology #TheAstrophysicalJournal #ApJ #astronomy #astrophysics #astrodon #science #research #STEM #Hooleilana #galaxies #BAO #BAOs #BaryonAcousticOscillations

Taylor Swift as Baryon Acoustic Oscillations

#TaylorSwift #Cosmology #Swifties #Universe #galaxies #BAO #BaryonAcousticOscillations #bigbang #theory #bigbangtheory #pop #culture #popculture #singer #art #fashion #model #dress #astrophysics #physics #astrodon #meme #science #memes #sciencememes #space #STEM