Observation of In-ice Askaryan Radiation from High-Energy Cosmic Rays

We present the first experimental evidence for in-ice Askaryan radiation -- coherent charge-excess radio emission -- from high-energy particle cascades developing in the Antarctic ice sheet. In 208 days of data recorded with the phased-array instrument of the Askaryan Radio Array, a previous analysis has incidentally identified 13 events with impulsive radiofrequency signals originating from below the ice surface. We here present a detailed reanalysis of these events. The observed event rate, radiation arrival directions, signal shape, spectral content, and electric field polarization are consistent with in-ice Askaryan radiation from cosmic ray air shower cores impacting the ice sheet. For the brightest events, the angular radiation pattern favors an extended cascade-like emitter over a pointlike source. An origin from the geomagnetic separation of charges in cosmic ray air showers is disfavored by the arrival directions and polarization. Considering the arrival angles, timing properties, and the impulsive nature of the passing events, the event rate is inconsistent with the estimation of the combined background from thermal noise events and on-surface events at the level of $5.1\,σ$.

arXiv.org

On this day, June 1, 2011: Final Landing of the Space Shuttle Endeavour

STS-134 delivered the Alpha Magnetic Spectrometer AMS-02 to the ISS, to measure the antimatter component of the cosmic rays spectrum.

Credit: NASA

📷 https://flic.kr/p/2npgLDz
ℹ️ https://ams02.space/

#Space #shuttle #spaceshuttle #Endeavour #AMS2 #antimatter #cosmology #cosmicrays #science #physics #OTD #astrodon

Harvard Astrophysicist Avi Loeb Decodes The Mysterious Blue Lights UAP Recorded By Apollo Astronauts On Moon

https://fed.brid.gy/r/https://in.mashable.com/science/109933/harvard-astrophysicist-avi-loeb-decodes-the-mysterious-blue-lights-uap-recorded-by-apollo-astronauts

Charge-dependent spectral softenings of primary cosmic-rays below the knee: https://arxiv.org/abs/2511.05409 -> The #DAMPE #satellite sheds light on the origin of #CosmicRays: https://www.unige.ch/medias/en/2026/le-satellite-dampe-eclaire-lorigine-des-rayons-cosmiques -> China's scientific satellite sheds new light on cosmic rays: https://english.news.cn/20260430/dca45ad2bde04c2eaf8a735f09ec1679/c.html
Charge-dependent spectral softenings of primary cosmic-rays below the knee

In most particle acceleration or propagation theories, the characteristic features of the cosmic ray spectra due to acceleration limits or propagation phase changes are charge dependent. Alternatively, the interaction scenario would expect mass dependent spectral features in general. The observational verification of which relation takes effect in nature is still lack due to the difficulty of measuring the spectra of individual particles up to very high energies. Here we report direct measurements of the carbon, oxygen, and iron spectra from ~20 gigavolts to ~100 teravolts (~60 teravolts for iron) with 9 years of on-orbit data collected by the Dark Matter Particle Explorer. Distinct spectral softenings have been directly detected in these spectra for the first time. Combined with the updated proton and helium spectra, the spectral softening appears universally at a rigidity of ~15 teravolts. A nuclei mass dependent softening is rejected at a confidence level of >99.999%. Possible interpretations of these results, including a nearby cosmic ray source and other models such as the propagation effect, are discussed.

arXiv.org

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
Une étoile mourante ferait bien mieux que le LHC : elle accélérerait naturellement des particules à des énergies extrêmes, bien au-delà de nos machines. sciencepost.fr/on-pensait-q... #Space #Science #Innovation #Astrophysics #ParticlePhysics #LHC #CosmicRays #ExtremeUniverse

On pensait que le LHC était l'...
On pensait que le LHC était l'ultime machine à particules : une étoile mourante fait mille fois mieux sans aucune technologie

Et si le plus puissant collisionneur de particules de l’univers n’était pas une machine terrestre comme le LHC ?

Sciencepost
Une étoile mourante ferait bien mieux que le LHC : elle accélérerait naturellement des particules à des énergies extrêmes, bien au-delà de nos machines.
https://sciencepost.fr/on-pensait-que-le-lhc-etait-lultime-machine-a-particules-une-etoile-mourante-fait-mille-fois-mieux-sans-aucune-technologie/
#Space #Science #Innovation #Astrophysics #ParticlePhysics #LHC #CosmicRays #ExtremeUniverse
On pensait que le LHC était l'ultime machine à particules : une étoile mourante fait mille fois mieux sans aucune technologie

Et si le plus puissant collisionneur de particules de l’univers n’était pas une machine terrestre comme le LHC ?

Sciencepost
CNRS 2026 confirme Marianne Lemoine parmi les médailles d’argent, choix attendu vu son poids en rayons cosmiques et travaux reconnus www.cnrs.fr/fr/actualite... #Space #Science #Astrophysics #Innovation #CosmicRays #CNRS #Research #NewSpace

Le CNRS dévoile ses médaillés ...
Le CNRS dévoile ses médaillés d’argent 2026

Le CNRS a décerné 26 médailles d’argent en 2026. Une reconnaissance importante pour celles et ceux qui font avancer la science.

CNRS
CNRS 2026 confirme Marianne Lemoine parmi les médailles d’argent, choix attendu vu son poids en rayons cosmiques et travaux reconnus https://www.cnrs.fr/fr/actualite/le-cnrs-devoile-ses-medailles-dargent-2026 #Space #Science #Astrophysics #Innovation #CosmicRays #CNRS #Research #NewSpace
Le CNRS dévoile ses médaillés d’argent 2026

Le CNRS a décerné 26 médailles d’argent en 2026. Une reconnaissance importante pour celles et ceux qui font avancer la science.

CNRS
Something different for this #WindowFriday - this is a small KBr window (it's transparent to mid-infrared radiation) on a #cryogenic sample holder inside a #vacuum chamber. As you can see, it's cracked, but luckily it still served the purpose as a substrate for growing ice layers on it. We then irradiated these layers in a #laboratory #astrochemistry experiment at #GANIL in Caen, France.

#science #Fensterfreitag #prettycold #cosmicrays