Tootfinder

Evidence for inverse Compton scattering in high-redshift Lyman-break galaxies: #galaxies reveal hidden effect from Big Bang: https://www.physics.ox.ac.uk/news/distant-galaxies-reveal-hidden-effect-big-bang

Big Bang KI-Festival: "Machen ist wie wollen, nur krasser"
Das Big-Bang-KI-Festival enthielt neben Weckrufen auch Diskussionen über Risiken von KI und Beiträge zur Drogen- und Mediensucht. Die ePA kassierte Lacher.

Topological Big Bangs: Reflection, Itty-Bitty Blenders, and Eternal Trumpets
Hubert Bray, James Wheeler
https://arxiv.org/abs/2509.11573 https://arxiv.org/…

Topological Big Bangs: Reflection, Itty-Bitty Blenders, and Eternal Trumpets
We discuss and formalize a topological means by which the initial singularity might be mollified, at the level of the spacetime manifold's structure, in classical cosmological models of a homogeneous expanding universe. The construction, dubbed a "reflective" topological big bang, generalizes Schrodinger's elliptic de Sitter space and is built to be compatible with the standard Friedmann-Lemaitre-Robertson-Walker (FLRW) picture of the large-scale universe, only minimally modifying it via some n…

Status:
Betittas - big bang theory (har börjat om på S1)
Ses igenom - nytvättade fönster utan måsbajs på
Känns - svett över hela kroppen

The Baby Universe is Fine and the CFT Knows It: On Holography for Closed Universes
Stefano Antonini, Pratik Rath, Martin Sasieta, Brian Swingle, Alejandro Vilar L\'opez
https://arxiv.org/abs/2507.10649

The Baby Universe is Fine and the CFT Knows It: On Holography for Closed Universes
Big bang/big crunch closed universes can be realized in AdS/CFT, even though they lack asymptotically AdS boundaries. With enough bulk entanglement, the bulk Hilbert space of a closed universe can be holographically encoded in the CFT. We clarify the relation of this encoding to observer-clone proposals and refute recent arguments about the breakdown of semiclassical physics in such spaces. In the limit of no bulk entanglement, the holographic encoding breaks down. The oft-cited one-dimensional…

High-Precision Measurement of D($\gamma$, $n$)$p$ Photodisintegration Reaction and Implications for Big-Bang Nucleosynthesis
Yinji Chen, Zirui Hao, Jianjun He, Toshitaka Kajino, Shung-ichi Ando, Yudong Luo, Hongrui Feng, Liyong Zhang, Gongtao Fan, Hongwei Wang, Hao Zhang, Zhilin Shen, Longxiang Liu, Hanghua Xu, Yue Zhang, Pu Jiao, Xinyue Li, Yuxuan Yang, Sheng Jin, Kaijie Chen, Wenqing Shen, Yugang Ma

High-Precision Measurement of D($γ$, $n$)$p$ Photodisintegration Reaction and Implications for Big-Bang Nucleosynthesis
We report on a high-precision measurement of the D($γ$, $n$)$p$ photodisintegration reaction at the newly commissioned Shanghai Laser Electron Gamma Source (SLEGS), employing a quasi-monochromatic $γ$-ray beam from Laser Compton Scattering. The cross sections were determined over $E_γ$=2.327-7.089 MeV, achieving up to a factor of 2.2 improvement in precision near the neutron separation threshold. Combined with previous data in a global Markov chain Monte Carlo (MCMC) analysis using dibaryon …

Probing Cosmic Neutrino Background through Parametric Fluorescence
Guo-yuan Huang, Shun Zhou
https://arxiv.org/abs/2507.10868 https://

Probing Cosmic Neutrino Background through Parametric Fluorescence
We point out that relic neutrinos from the Big Bang may induce the parametric fluorescence in molecular systems, which offers a novel way to discover cosmic neutrino background. By coherently scattering with molecular energy levels, a massive neutrino can spontaneously ``decay" into a lighter neutrino and an infrared signal photon, i.e., $ν^{}_{i} + M \to ν^{}_{j} + γ^{}_{\rm S} + M$, where the molecular state $M$ remains unchanged after the scattering. Because the amplitudes of different ra…

The Signature of Sub-galactic Dark Matter Clumping in the Global 21-cm Signal of Hydrogen
Hyunbae Park, Rennan Barkana, Naoki Yoshida, Sudipta Sikder, Rajesh Mondal, Anastasia Fialkov
https://arxiv.org/abs/2509.11055

The Signature of Sub-galactic Dark Matter Clumping in the Global 21-cm Signal of Hydrogen
It is thought that the Universe went through an early period known as the Dark Ages, during which primeval density fluctuations grew to form the first luminous objects, marking the beginning of Cosmic Dawn around 100 million years after the Big Bang. The 21-cm line of hydrogen atoms is the most promising probe of these epochs, with extensive observational efforts underway. We combine hydrodynamical simulations with a large-scale grid in order to precisely calculate the effect of non-linear stru…

Evidence of Galactic Center Expansion from Gaia DR3 Stars along the South North Axis: Implications for the JWST Early Galaxy Problem
G. S. Karapetian, L. E. Byzalov, M. A. Hovhannisyan, L. A. Mahtessian, A. P. Mahtessian
https://arxiv.org/abs/2509.10856

Evidence of Galactic Center Expansion from Gaia DR3 Stars along the South North Axis: Implications for the JWST Early Galaxy Problem
Recent observations with the James Webb Space Telescope (JWST) have revealed massive, evolved galaxies only a few hundred million years after the Big Bang, challenging standard cosmological models. To test the hypothesis that the Galactic nucleus may act as a source of matter and energy capable of accelerating galaxy formation, we examined whether the Milky Way itself shows signs of central activity. Expansion of the Galactic center would imply such activity in its nuclear region. To investigat…

SIV Guided Resolution of the Lithium-7 BBN Problem
Vesselin G. Gueorguiev
https://arxiv.org/abs/2509.10721 https://arxiv.org/pdf/2509.10721

SIV Guided Resolution of the Lithium-7 BBN Problem
A possible resolution of the $^7$Li problem within the Standard Model Big-Bang Nucleosynthesis is presented. The key idea originates from the application of the Scale-Invariant Vacuum (SIV) paradigm to the BBN. However, here we arrive at the conclusion that Reparametrization Invariant Symmetry Scaling (RISS) is the more appropriate framework for the epoch of the BBN and use the SIV only as a guidance framework. The outcome is $χ^2<0.04$ fit to the observed primordial abundances of $^4$He, D/H,…

No Hiding in the Dark: Cosmological Bounds on Heavy Neutral Leptons with Dark Decay Channels
P. S. Bhupal Dev, Quan-feng Wu, Xun-Jie Xu
https://arxiv.org/abs/2507.12270

No Hiding in the Dark: Cosmological Bounds on Heavy Neutral Leptons with Dark Decay Channels
Heavy neutral leptons (HNLs) are well-motivated new physics candidates. The mixing of sub-GeV HNLs with active neutrinos is severely constrained by cosmology. In particular, the success of Big Bang Nucleosynthesis (BBN) requires the HNL lifetime to be shorter than about 0.02 sec if they were in thermal equilibrium, thus excluding a wide range of mixing angles accessible to terrestrial experiments. In order to justify the laboratory searches in this cosmologically-forbidden region, it is often a…

The Big Bang's Glowing 'Echo' May Be Something Else Entirely : ScienceAlert
https://www.sciencealert.com/the-big-bangs-glowing-echo-may-be-something-else-entirely

Lowering the Horizon on Dark Energy: A Late-Time Response to Early Solutions for the Hubble Tension
Tal Adi
https://arxiv.org/abs/2509.12331 https://arxiv.…

Lowering the Horizon on Dark Energy: A Late-Time Response to Early Solutions for the Hubble Tension
We present a model-independent null test of the late-time cosmological response to a reduced sound horizon, as typically required by early-universe solutions to the Hubble tension. In this approach, we phenomenologically impose a shorter sound horizon without modeling early-universe physics to isolate its impact on late-time dark energy inference. Using baryon acoustic oscillations (BAO), supernovae (SN), big bang nucleosynthesis (BBN), and local $H_0$ data, while explicitly avoiding CMB anisot…

Formation of Cosmic Noon Protogalaxies via Quasar-Induced Fragmentation of a Cosmic Filament
Marko Mi\'ci\'c, Themiya Nanayakkara, Xinyu Dai, Jeremy Bailin, Miljan Kol\v{c}i\'c
https://arxiv.org/abs/2509.10670

Formation of Cosmic Noon Protogalaxies via Quasar-Induced Fragmentation of a Cosmic Filament
When black hole jets encounter ambient medium, they can compress the gas, trigger star formation, and create stellar clusters containing tens of thousands of stars. Here, we report a remarkable discovery of such a phenomenon that happened just 2.2 billion years after the Big Bang, during the Cosmic Noon era. Quasar SDSSJ141924.44+532315.5, powered by a one-billion-solar-mass black hole, is seen blasting a powerful jet that interacts with a hypermassive gas reservoir, creating a fascinating, clu…

New constraints on $Z^\prime$ from captured dark matter annihilation in astrophysical objects
Basabendu Barman, Pooja Bhattacharjee, Arindam Das
https://arxiv.org/abs/2509.12192

New constraints on $Z^\prime$ from captured dark matter annihilation in astrophysical objects
Considering dark matter capture in astrophysical objects such as neutron stars and brown dwarfs, followed by their annihilation into two neutrino and four neutrino final states, we derive new constraints on the mass and coupling of a novel abelian gauge boson $Z^\prime$ arising from an anomaly-free $U(1)$ extension of the Standard Model. We further confront these astrophysical limits with complementary bounds from the Planck-observed relic abundance via the freeze-in mechanism, big bang nucleos…

My Mastodon instance updated UI.😍
It's is more clear and usable...I hate it!😆
[this joke was stolen from Big Bang Theory]

Lessons from a Big-Bang Integration: Challenges in Edge Computing and Machine Learning
Alessandro Aneggi, Andrea Janes
https://arxiv.org/abs/2507.17270 htt…

Lessons from a Big-Bang Integration: Challenges in Edge Computing and Machine Learning
This experience report analyses a one year project focused on building a distributed real-time analytics system using edge computing and machine learning. The project faced critical setbacks due to a big-bang integration approach, where all components developed by multiple geographically dispersed partners were merged at the final stage. The integration effort resulted in only six minutes of system functionality, far below the expected 40 minutes. Through root cause analysis, the study identifi…

SPHEREx and JWST reveal what comet 3I/ATLAS is... and isn't - Big Think #astronomy

SPHEREx and JWST reveal what comet 3I/ATLAS is... and isn't
Designed to map galaxies, the SPHEREx mission's first science result is instead about interstellar interloper 3I/ATLAS. No, it's not aliens.

🍇 The universe's secret harvest: Shedding light on 'the cosmic grapes'
#astronomy

The universe's secret harvest: Shedding light on 'the cosmic grapes'
Astronomers have discovered a remarkably clumpy rotating galaxy that existed just 900 million years after the Big Bang, shedding new light on how galaxies grew and evolved in the early universe. Nicknamed the "Cosmic Grapes," the galaxy appears to be composed of at least 15 massive star-forming clumps—far more than current theoretical models predict could exist within a single rotating disk at this early time.

Primordial Black Holes Evaporating before Big Bang Nucleosynthesis
Quan-feng Wu, Xun-Jie Xu
https://arxiv.org/abs/2509.05618 https://arxiv.org/pdf/2509.056…

Primordial Black Holes Evaporating before Big Bang Nucleosynthesis
Primordial black holes (PBHs) formed from the collapse of density fluctuations provide a unique window into the physics of the early Universe. Their evaporation through Hawking radiation around the epoch of Big Bang nucleosynthesis (BBN) can leave measurable imprints on the primordial light-element abundances. In this work, we analyze in detail the effects of PBHs evaporating before BBN, with various intermediate steps understood analytically, and obtain the BBN constraint on PBHs within a tran…

Probing Light Primordial Black Holes through Non-cold Dark Matter
Yu-Ming Chen
https://arxiv.org/abs/2509.09767 https://arxiv.org/pdf/2509.09767

Probing Light Primordial Black Holes through Non-cold Dark Matter
We study the matter power spectrum constraint on primordial black holes (PBH) by the dark matter (DM) emitted through Hawking radiation. We particularly focus on the scenario where PBH, with mass ranges between 1g and $10^9$g, evaporates before big-bang nucleosynthesis (BBN). Addition to that, we consider the case where PBH abundance is scarce and there is no early PBH domination taking place. On the DM side, we assume a fraction of the population is produced from PBH evaporation, while the rem…

Nomad cluster powered down.
Everything is now running in a k3s monocluster on a Radxa Rock5b
What feels insane is I started this project in December.... But lots of little edge cases and such to solve for just like any real migration.
I'm using fluxcd and all my configurations are pretty decent. I could do a big-bang redeploy on a new machine and everything would work.
#homelab

A Theory of the Big Bang in McTaggart's Time
Paul Merriam
https://arxiv.org/abs/2508.15863 https://arxiv.org/pdf/2508.15863

A Theory of the Big Bang in McTaggart's Time
There are long standing questions about the Big Bang What were its properties? Was there nothing before it? Was the universe always here? Many conceptual issues revolve around time. This paper gives a novel model based on McTaggarts temporal distinction between the A-series future-present-past and B-series earlier-times to later times. These series are useful while situated in a Presentist and Fragmentalist account of quantum mechanics, one in which the consistency with the Special Relativity i…

Few-grid-point simulations of Big Bang singularity in quantum cosmology
Miloslav Znojil
https://arxiv.org/abs/2506.14848 https://arxi…

Few-grid-point simulations of Big Bang singularity in quantum cosmology
In the context of the current lack of compatibility of the classical and quantum approaches to gravity, exactly solvable elementary pseudo-Hermitian quantum models are analyzed supporting the acceptability of a point-like form of Big Bang. The purpose is served by a hypothetical (non-covariant) identification of the ``time of Big Bang'' with the Kato's exceptional-point parameter $t=0$. Consequences (including the ambiguity of the patterns of unfolding of the singularity after Big Bang) are stu…

A fast radio burst from the first 3 billion years of the Universe
Manisha Caleb, Themiya Nanayakkara, Benjamin Stappers, In\'es Pastor-Marazuela, Ilya S. Khrykin, Karl Glazebrook, Nicolas Tejos, J. Xavier Prochaska, Kaustubh Rajwade, Lluis Mas-Ribas, Laura N. Driessen, Wen-fai Fong, Alexa C. Gordon, Jordan Hoffmann, Clancy W. James, Fabian Jankowski, Lordrick Kahinga, Michael Kramer, Sunil Simha, Ewan D. Barr, Mechiel Christiaan Bezuidenhout, Xihan Deng, Zeren Lin, Lachlan Marnoch,…

A fast radio burst from the first 3 billion years of the Universe
Fast radio bursts (FRBs) are enigmatic millisecond-duration signals which encode otherwise unattainable information on the plasma which permeates our Universe, providing insights into magnetic fields and gas distributions. Here we report the discovery of FRB 20240304B originating at redshift 2.148 +/- 0.001 corresponding to just 3 billion years after the Big Bang. FRB 2024030 was detected with the MeerKAT radio telescope and localized to a low-mass, clumpy, star forming galaxy using the James W…

Witnessing the violent, merger-driven formation of an extremely massive galaxy 1.7 Gyr after the Big Bang
Lura K. Pitchford, Joseph Cairns, Duncan Farrah, David Clements, Evanthia Hatziminaoglou, Ismael P\'erez-Fournon, Lingyu Wang
https://arxiv.org/abs/2509.04584

Witnessing the violent, merger-driven formation of an extremely massive galaxy 1.7 Gyr after the Big Bang
We combine near-infrared imaging in two bands from the Hubble Space Telescope (HST) with archival observations of molecular gas to study SDSS J160705.16+533558.6 (J1607), an extremely luminous broad-line quasar at $z = 3.65$ that is also bright in the submillimeter (sub-mm). Via subtraction of the quasar point spread function, we show that its host galaxy is massive, with a stellar mass of $(5.8 \pm 3.0) \times 10^{11}$ M$_{\odot}$, making it comparable to giant early-type galaxies (ETGs) at $z…

Presentist Fragmentalism and Quantum Mechanics
Paul Merriam
https://arxiv.org/abs/2508.06006 https://arxiv.org/pdf/2508.06006

Presentist Fragmentalism and Quantum Mechanics
This paper states and gives three applications of a novel Presentist Fragmentalist interpretation of quantum mechanics. In a cognate paper it was explicitly shown this kind of presentism is consistent with special relativity and that it has implications for how to understand time as it relates to the Big Bang, 5. In this paper we narrowly focus on three applications. These are surely the most important conundrums for any proposed interpretation of quantum mechanics, Schrodingers Cat, Bell nonlo…

Consistent $N_{\rm eff}$ fitting in big bang nucleosynthesis analysis
Sougata Ganguly, Tae Hyun Jung, Seokhoon Yun
https://arxiv.org/abs/2507.23354 https://

Consistent $N_{\rm eff}$ fitting in big bang nucleosynthesis analysis
The effective number of neutrino species, $N_{\rm eff}$, serves as a key fitting parameter extensively employed in cosmological studies. In this work, we point out a fundamental inconsistency in the conventional treatment of $N_{\rm eff}$ in big bang nucleosynthesis (BBN), particularly regarding its applicability to new physics scenarios where $ΔN_{\rm eff}$, the deviation of $N_{\rm eff}$ from the standard BBN prediction, is negative. To ensure consistent interpretation, it is imperative to e…

Frequent Extreme Galaxy-scale Outflows among Luminous Early Quasars
Weizhe Liu, Xiaohui Fan, Huan Li, Richard Green, Jinyi Yang, Xiangyu Jin, Jianwei Lyu, Maria Pudoka, Yongda Zhu, Eduardo Banados, Silvia Belladitta, Thomas Connor, Tiago Costa, Roberto Decarli, Anna-Christina Eilers, Hyunsung Jun, Madeline A. Marshall, Chiara Mazzucchelli, Jan-Torge Schindler, Yue Shen, Sylvain Veilleux, Julien Wolf, Huanian Zhang, Mingyang Zhuang, Siwei Zou, Mingyu Li

Frequent Extreme Galaxy-scale Outflows among Luminous Early Quasars
The existence of abundant post-starburst/quiescent galaxies just $\sim$1-2 Gyrs after the Big Bang challenges our current paradigm of galaxy evolution. Cosmological simulations suggest that quasar feedback is likely the most promising mechanism responsible for such rapid quenching. Here we report a high detection rate (6/27) of exceptionally fast and powerful galaxy-scale outflows traced by [O III] emission in z $\sim$ 5-6 luminous quasars as revealed by the James Webb Space Telescope (JWST), w…

Multiverse Predictions for Habitability: Fundamental Physics and Galactic Habitability
McCullen Sandora
https://arxiv.org/abs/2509.08220 https://arxiv.org/…

Multiverse Predictions for Habitability: Fundamental Physics and Galactic Habitability
In the multiverse hypothesis, a range of universes exist with differing values of our physical constants. Here, we investigate how the probabilities of observing our values of these constants depend on the assumptions made about the theories governing particle physics and cosmology, along with habitability. The particle physics effects we consider include constraints on the Higgs vacuum expectation value from big bang nucleosynthesis and supernovae, grand unified theories (GUTs), and standard m…

Research day means that I can ditch my corporate windows computer and work on my own machine, a penguin powered on of course. Feel like Sheldon Cooper when I can acctually do work the right way. #meme #memes #ubuntu

Stability of Big Bang singularity for the Einstein-Maxwell-scalar field-Vlasov system in the full strong sub-critical regime
Xinliang An, Taoran He, Dawei Shen
https://arxiv.org/abs/2507.18585

Stability of Big Bang singularity for the Einstein-Maxwell-scalar field-Vlasov system in the full strong sub-critical regime
In $3+1$ dimensions, we study the stability of Kasner solutions for the Einstein-Maxwell-scalar field-Vlasov system. This system incorporates gravity, electromagnetic, weak and strong interactions for the initial stage of our universe. Due to the presence of the Vlasov field, various new challenges arise. By observing detailed mathematical structures and designing new delicate arguments, we identify a new strong sub-critical regime and prove the nonlinear stability with Kasner exponents lying i…

A conformal basis for cosmology with energy conservation
J. M. Greben
https://arxiv.org/abs/2508.00948 https://arxiv.org/pdf/2508.00948

A conformal basis for cosmology with energy conservation
In the standard FRW formalism, the scale factor is assumed to describe the expansion of the universe. However, by examining empty space with a positive cosmological constant (i.e., a de Sitter space), we find that this assumption is incorrect. When described in conformal time, the associated conformal metric exhibits a big bang singularity where the effective vacuum energy density diverges, dominating the early universe. The corresponding FRW scale factor decreases after the big bang, so that i…

New bounds on Memory Burdened Primordial Black Holes from Big Bang Nucleosynthesis
Arnab Chaudhuri, Kazunori Kohri, Valentin Thoss
https://arxiv.org/abs/2506.20717

New bounds on Memory Burdened Primordial Black Holes from Big Bang Nucleosynthesis
Primordial black holes (PBHs) with masses below $10^9\,\rm{g}$ are typically assumed to have negligible cosmological impact due to their rapid evaporation via Hawking radiation. However, the 'memory burden' effect, which is a quantum suppression of PBH evaporation, can dramatically alter their decay dynamics. In this work, we revisit early-Universe constraints on ultralight PBHs in this mass range, demonstrating that memory burden significantly alters previous constraints. We compute new cosmol…

Gravitational waves induced by matter isocurvature in general cosmologies
Guillem Dom\`enech, Jan Tr\"ankle
https://arxiv.org/abs/2509.02122 https://a…

Gravitational waves induced by matter isocurvature in general cosmologies
The expansion history and content of the Universe between the end of inflation and the onset of Big Bang Nucleosynthesis is mostly unknown. In this paper, we study gravitational waves (GWs) induced by matter isocurvature fluctuations in a generic perfect fluid background as a novel probe of the physics of the very early Universe. We analytically compute the induced GW kernel and analyze the spectral GW energy density for a sharply peaked isocurvature power spectrum. We show that the spectral sh…

Primordial black hole induced gravitational waves in $f(R)$ gravity
Theodoros Papanikolaou, Salvatore Capozziello
https://arxiv.org/abs/2508.03939 https://…

Primordial black hole induced gravitational waves in $f(R)$ gravity
Ultra-light primordial black holes (PBHs) with masses $M_\mathrm{PBH}<5\times 10^{8}\mathrm{g}$ can trigger an early matter-dominated (eMD) era before Big Bang Nucleosynthesis (BBN) and reheat the Universe through their evaporation. Notably, the initial isocurvature in nature PBH energy density fluctuations can induce abundantly gravitational waves (GWs) due to second-order gravitational effects. In this work, we study this induced GW signal within the context of $f(R)$ gravity theories investi…

New Determination of the $^{14}$C(n, $\gamma$)$^{15}$C Reaction Rate and Its Astrophysical Implications
Yuchen Jiang (China Institute of Atomic Energy, Beijing, China), Zhenyu He (School of Physics, International Research Center for Big-Bang Cosmology and Element Genesis, Peng Huanwu Collaborative Center for Research and Education, Beihang University, Beijing, China), Yudong Luo (School of Physics, Peking University, and Kavli Institute for Astronomy and Astrophysics, Peking University…

New Determination of the $^{14}$C(n, $γ$)$^{15}$C Reaction Rate and Its Astrophysical Implications
We present a novel experiment to investigate the spectroscopic factor of the $^{15}$C ground state for the first time using single-neutron $removal$ transfer reactions on $^{15}$C. Two consistent spectroscopic factors were derived from the (p, d) and (d, t) reactions, which were subsequently used to deduce the $^{14}$C(n, $γ$)$^{15}$C reaction cross section and the corresponding stellar reaction rate. A typical cross section of (3.89 $\pm$ 0.76) $μ$b is determined at $E_\mathrm{_{c.m.}}$ = 23…

Constraints on R\'{e}nyi Entropy through Primordial Big-Bang Nucleosynthesis and Baryogenesis
Ahmad Sheykhi, Ava Shahbazi Sooraki
https://arxiv.org/abs/2507.14250 https://…

Constraints on Rényi Entropy through Primordial Big-Bang Nucleosynthesis and Baryogenesis
The Rényi entropy, a one-parameter generalization of Boltzmann-Gibbs entropy, offers a promising framework for probing quantum gravitational effects in cosmology. By modifying the entropy-area relation of the apparent horizon, Rényi entropy can alter the expansion dynamics of the early universe, with potential implications for Big-Bang Nucleosynthesis. In this work, we derive the modified Friedmann equations within the Rényi entropy paradigm and investigate their impact on the primordial abu…

Hot New Early Dark Energy: Dark Radiation Matter Decoupling
Mathias Garny, Florian Niedermann, Henrique Rubira, Martin S. Sloth
https://arxiv.org/abs/2508.03795 https://

Hot New Early Dark Energy: Dark Radiation Matter Decoupling
We present a microscopic model of the dark sector that resolves the Hubble tension within standard current datasets based on well-known fundamental principles, gauge symmetry and spontaneous symmetry breaking. It builds on the Hot New Early Dark Energy (Hot NEDE) setup, featuring a dark $SU(N)$ gauge symmetry broken to $SU(N-1)$ in a supercooled phase transition that creates a thermal bath of self-interacting dark radiation in the epoch between Big Bang Nucleosynthesis and recombination. Adding…

Primordial high energy neutrinos: theoretical/observational constraints and sharp spectral features
Nicolas Grimbaum Yamamoto, Thomas Hambye
https://arxiv.org/abs/2507.02063

Primordial high energy neutrinos: theoretical/observational constraints and sharp spectral features
Among the few ways that allow or could allow us to probe the early Universe from the observation of a flux of primordial particles, there is one possibility which has been little studied: the observation today of high energy neutrinos which could have been emitted shortly after the Big Bang, from the decay or annihilation of early universe relics. We perform a general study of such a possibility. To this end we first emphasise that these neutrinos could display various kinds of sharp spectral f…

Primordial black holes in the main lensing galaxy of FBQ 0951 2635
Daniel Isla, Luis J. Goicoechea, Ana Esteban-Guti\'errez, Vyacheslav N. Shalyapin, Rodrigo Gil-Merino, Jose M. Diego, Eleana Ruiz-Hinojosa
https://arxiv.org/abs/2509.02193

Primordial black holes in the main lensing galaxy of FBQ 0951+2635
Although dark matter in galaxies may consist of elementary particles different from those that make up ordinary matter and that would be smoothly distributed (still undetected), the so-called primordial black holes (PBHs) formed soon after the initial Big Bang are also candidates to account for a certain fraction of mass in galaxies. In this paper, we focused on the main lensing galaxy ($z$ = 0.260) of the doubly imaged gravitationally lensed quasar FBQ 0951+2635 ($z$ = 1.246) for probing possi…

Cosmology with Distinct Functions $f$ of the Non-metricity Scalar $Q$ : A Dynamical System Approach
Promila Biswas, Subhajit Pal, Ritabrata Biswas, Satyajit Pal
https://arxiv.org/abs/2506.21646

Cosmology with Distinct Functions $f$ of the Non-metricity Scalar $Q$ : A Dynamical System Approach
Symmetric teleparallel gravity is one among the general relativistic trinity which deals with the non-metricity scalar $Q$. In the Einstein Hilbert action, a function of $Q$ is chosen to be the main contributory part of the Lagrangian and a modified theory of gravity is constructed. In literature, different structures of the function of $Q$ are found which sustain several astrophysical observations like Big Bang nucleosynthesis, late-time cosmic acceleration etc. Autonomous systems for each suc…

JADES-GS-z14-1: A Compact, Faint Galaxy at $z\approx14$ with Weak Metal Lines from Extremely Deep JWST MIRI, NIRCam, and NIRSpec Observations
Zihao Wu, Daniel J. Eisenstein, Benjamin D. Johnson, Peter Jakobsen, Stacey Alberts, Santiago Arribas, William M. Baker, Andrew J. Bunker, Stefano Carniani, St\'ephane Charlot, Jacopo Chevallard, Mirko Curti, Emma Curtis-Lake, Francesco D'Eugenio, Kevin Hainline, Jakob M. Helton, Tiger Yu-Yang Hsiao, Xihan Ji, Zhiyuan Ji, Tobias J. Looser…

JADES-GS-z14-1: A Compact, Faint Galaxy at $z\approx14$ with Weak Metal Lines from Extremely Deep JWST MIRI, NIRCam, and NIRSpec Observations
JWST has shed light on galaxy formation and metal enrichment within 300 Myr of the Big Bang. While luminous galaxies at $z > 10$ often show significant [O III]$λλ$4959, 5007 emission lines, it remains unclear whether such features are prevalent among fainter, more typical galaxies due to observational limits. We present deep imaging and spectroscopy of JADES-GS-z14-1 at $z_\mathrm{spec}=13.86^{+0.04}_{-0.05}$, currently the faintest spectroscopically confirmed galaxy at $z\approx 14$. It sere…

Post-Reheating Inflaton Production as a Probe of Reheating Dynamics
Kunio Kaneta, Tomo Takahashi, Natsumi Watanabe
https://arxiv.org/abs/2508.20402 https://

Post-Reheating Inflaton Production as a Probe of Reheating Dynamics
Cosmological reheating bridges the inflationary epoch and the hot big bang phase, yet its underlying dynamics remain poorly understood. In this work, we investigate a minimal scenario in which the inflaton evolves under a simple power-law potential during reheating and interacts with other particles via renormalizable couplings. We show that inflaton quanta can be regenerated from the thermal bath even after the decay of the coherent inflaton field, unveiling a previously overlooked channel for…

The z = 9.625 Cosmic Gems Galaxy was a "Compact Blue Monster" Propelled by Massive Star Clusters
E. Vanzella, M. Messa, A. Adamo, F. Loiacono, M. Oguri, K. Sharon, L. D. Bradley, P. Bergamini, M. Meneghetti, A. Claeyssens, B. Welch, M. Bradac, A. Zanella, A. Bolamperti, F. Calura, T. Y-Y. Hsiao, E. Zackrisson, M. Ricotti, L. Christensen, J. M. Diego, F. E. Bauer, X. Xu, S. Fujimoto, C. Grillo, M. Lombardi, P. Rosati, T. Resseguier, A. Zitrin, A. Bik, J. Richard, Abdurro'…

The z = 9.625 Cosmic Gems Galaxy was a "Compact Blue Monster" Propelled by Massive Star Clusters
The recent discovery of five massive stellar clusters at z=9.625 in the Cosmic Gems has raised the question about the formation mechanism of star clusters in the first half Gyr after the Big-Bang. We infer the total stellar mass in clusters by normalizing and integrating the stellar cluster mass function (SCMF, dn(M)/dM ~ (n$_0$) $M^β$), assuming three different slopes $β$ = -1.5, -2.0 and -2.5 and different lower-mass limits between $10^2$ and $10^5$ Msun. The total integrated cluster stella…

Return of the Lepton Number: Sterile Neutrino Dark Matter Production and the Revival of the Shi-Fuller Mechanism
Cannon M. Vogel, Helena Garc\'ia Escudero, Julien Froustey, Kevork N. Abazajian
https://arxiv.org/abs/2507.18752

Return of the Lepton Number: Sterile Neutrino Dark Matter Production and the Revival of the Shi-Fuller Mechanism
We explore resonant production of sterile neutrino dark matter via the Shi-Fuller (SF) mechanism, revisiting its cosmological viability in light of recent results demonstrating that lepton-number asymmetries $L_α\gtrsim 1$ at temperatures $T > 20\rm\,MeV$ are consistent with Big Bang Nucleosynthesis (BBN). Using a quasi-classical Boltzmann transport calculation of the dark matter production, we compute the non-thermal phase space distributions of sterile neutrinos across a broad range of parti…

Rapid late-time reionization: constraints and cosmological implications
Willem Elbers
https://arxiv.org/abs/2508.21069 https://arxiv.org/pdf/2508.21069

Rapid late-time reionization: constraints and cosmological implications
We present constraints on the reionization optical depth, $τ$, obtained using several independent methods. First, we perform a non-parametric reconstruction of the reionization history, using Lyman-$α$ constraints on the evolution of the volume-averaged neutral hydrogen fraction, $x_\mathrm{HI}(z)$, including recent results from the James Webb Space Telescope. When combined with baryon acoustic oscillation (BAO) measurements from DESI and Big Bang nucleosynthesis constraints, these data imply…

Replaced article(s) found for gr-qc. https://arxiv.org/list/gr-qc/new
[1/1]:
Developments of initial data on big bang singularities for the Einstein-nonlinear scalar field eq...

Crosslisted article(s) found for astro-ph.CO. https://arxiv.org/list/astro-ph.CO/new
[1/1]:
- Big Bang as spacetime defect
F. R. Klinkhamer
https://

Replaced article(s) found for astro-ph.GA. https://arxiv.org/list/astro-ph.GA/new
[1/1]:
- A grand-design spiral galaxy 1.5 billion years after the Big Bang with JWST
Rashi Jain, Yogesh Wadadekar

Primordial magnetogenesis from a supercooled dynamical electroweak phase transition
Martin Arteaga Tupia, Anish Ghoshal, Alessandro Strumia
https://arxiv.org/abs/2506.16387

Primordial magnetogenesis from a supercooled dynamical electroweak phase transition
Observations of $γ$-ray from blazars suggest the presence of magnetic fields in the intergalactic medium, which may require a primordial origin. Intense enough primordial magnetic fields can arise from theories of dynamical electroweak symmetry breaking during the big bang, where supercooling is ended by a strongly first order phase transition. We consider theories involving new scalars and possibly vectors, including thermal particle dark matter candidates. Intense enough magnetic fields can …

Comprehensively Constraining Ultra-Light Primordial Black Holes Through Relic Formation and Early Mergers
Amirah Aljazaeri, Christian T. Byrnes
https://arxiv.org/abs/2506.16154

Comprehensively Constraining Ultra-Light Primordial Black Holes Through Relic Formation and Early Mergers
We investigate constraints on the least explored, smallest mass scales of primordial black holes (PBHs), which evaporate prior to Big Bang Nucleosynthesis (BBN). Our study examines the impact of Planck-mass relics on the allowed fraction of dark matter composed of PBHs ($f_{PBH}$), as well as on the resulting stochastic gravitational wave background and the formation of primordial binaries. We discuss how these binaries and early mergers lead to longer PBH lifetimes, extending the reach of the …

Little Red Dots as Direct-collapse Black Hole Nurseries
Elia Cenci, Melanie Habouzit
https://arxiv.org/abs/2508.14897 https://arxiv.org/pdf/2508.14897

Little Red Dots as Direct-collapse Black Hole Nurseries
The James Webb Space Telescope recently uncovered a population of massive black holes (BHs) in the first billion years after the Big Bang. Among these high-redshift BH candidates, observations have identified a class of active galactic nuclei candidates, dubbed Little Red Dots (LRDs), with extraordinarily compact gas reservoirs and peculiar spectral features. LRDs clearly emerge at redshift z<8 and their abundance declines by z<5. Recent theoretical studies have explored the link between LRDs a…

Lithium evolution in the Galactic thin disc from Main-Sequence and early Red-Giant-Branch stars
C. T. Nguyen, G. Cescutti, F. Matteucci, F. Rizzuti, A. Mucciarelli, D. Romano, L. Magrini, A. J. Korn, A. Bressan, L. Girardi
https://arxiv.org/abs/2508.14594

Lithium evolution in the Galactic thin disc from Main-Sequence and early Red-Giant-Branch stars
The role of novae as producers of galactic lithium has been suggested since the 1970s, and it has been reconsidered recently with the detection of $^7$Be in their outbursts. At the same time, stellar models are moving forward to comprehend the discrepancy between the primordial lithium abundance predicted by the standard Big Bang Nucleosynthesis theory and the measured value of old dwarf stars. In this work, we follow the evolution of $^7$Li in the galactic thin disc starting from a primordial …