Tootfinder

The “Bavarian Forest Nature Park” and the “Bavarian Forest National Park” have been officially recognized as an international star park by DarkSky International (DSI): #StarPark.”

I found this a nice and interesting video essay about the Dark Forest hypothesis in sci-fi literature:
https://www.youtube.com/watch?v=X0SvgT9Lc2M
I usually don't dare clicking on new recommended channels on Youtube because I don't know if that's some crap…

@…
This cartoon is from Tom Gauld's book: Revenge of the Librarians
copyright 2022
Get ALL his books. Read them. ALL of them are the best one.
#Reading

DeepCHART: Mapping the 3D dark matter density field from Ly$\alpha$ forest surveys using deep learning
Soumak Maitra (TIFR), Matteo Viel, Girish Kulkarni
https://arxiv.org/abs/2507.00135

DeepCHART: Mapping the 3D dark matter density field from Ly$α$ forest surveys using deep learning
We present DeepCHART (Deep learning for Cosmological Heterogeneity and Astrophysical Reconstruction via Tomography), a deep learning framework designed to reconstruct the three-dimensional dark matter density field at redshift $z=2.5$ from Ly$α$ forest spectra. Leveraging a 3D variational autoencoder with a U-Net architecture, DeepCHART performs fast, likelihood-free inference, accurately capturing the non-linear gravitational dynamics and baryonic processes embedded in cosmological hydrodynam…

We were in Mt Forest, #Ontario for a performance last night when #tornado warning alarms went off on all the phones. Tremendous amount of lightning, but haven't seen any official reports of damage yet. This is what the sky looked like at 9 pm 😬.

Summer solstice 2025
Short (5km), but absolutely stunning hike with my son to make the most of the solstice evening, with some grand views, sunset, radler and an adventurous T3 path along a steep 400m cliff drop-off... Back at the trailhead after 10pm, still not dark. Summer evenings...
#SilentSunday

Dark Matter Freeze-In and Small-Scale Observables: Novel Mass Bounds and Viable Particle Candidates
Francesco D'Eramo, Alessandro Lenoci, Ariane Dekker
https://arxiv.org/abs/2506.13864

Dark Matter Freeze-In and Small-Scale Observables: Novel Mass Bounds and Viable Particle Candidates
The suppression of cosmological structure at small scales is a key signature of dark matter (DM) produced via freeze-in in the low-mass regime. We present a comprehensive analysis of its impact, incorporating recent constraints from Milky Way satellite counts, strong gravitational lensing with JWST data, and the Lyman-$α$ forest. We adopt a general strategy to translate existing warm dark matter (WDM) bounds into lower mass limits for a broad class of DM candidates characterized by quasi-therm…

Star formation drivers across the M33 disk
Edvige Corbelli, Bruce Elmegreen, Sara Ellison, Simone Bianchi
https://arxiv.org/abs/2507.01158 https://

Star formation drivers across the M33 disk
We investigate the star formation process across the disk of M33 using a multiwavelength dataset and disk dynamics. We computed numerically equilibrium values of gas densities and scale heights across the disk, taking into account dark matter and testing several analytic approximations that are often used to estimate these variables and the hydrostatic pressure. Orthogonal regressions and hierarchical Bayesian models, as well as random forest (RF) analyses, were used to establish the fundamenta…

Universal lower bound on the axion decay constant from free streaming effects
Keisuke Harigaya, Wayne Hu, Rayne Liu, Huangyu Xiao
https://arxiv.org/abs/2507.01956

Universal lower bound on the axion decay constant from free streaming effects
We show that enhancement of the axion relic abundance compared to the standard misalignment contribution generically leads to the production of nonzero momentum axion modes, resulting in warm dark matter behavior and enhanced isocurvature perturbations. It leads to universal constraints on the axion parameter space that are independent of detailed model assumptions and cosmological history. For models enhancing relic abundance with gradient axion modes, observations of the Lyman-$α$ forest imp…

My son, my wife and our friend who helped us put up hay this evening (I helped too!)
#photo #photography #portrait #hay

The effects of continuum fitting on Lyman-$\alpha$ forest correlations
Nicolas Busca, James Rich, Julian Bautista, Andrei Cuceu, Andreu Font-Ribera, Julien Guy, Hiram K. Herrera-Alcantar, Julianna Stermer, Christophe Balland, J. Aguilar, S. Ahlen, D. Bianchi, D. Brooks, T. Claybaugh, A. de la Macorra, P. Doel, S. Ferraro, J. E. Forero-Romero, E. Gazta\~naga, C. Gordon, G. Gutierrez, M. Ishak, R. Kehoe, D. Kirkby, A. Kremin, M. Landriau, L. Le Guillou, C. Magneville, P. Martini, R. Miqu…

The effects of continuum fitting on Lyman-$α$ forest correlations
Correlations of fluctuations of the flux in Lyman-$α$ forests of high-redshift quasars have been observed by the Baryonic Acoustic Oscillation Spectroscopy Survey (BOSS) and the Dark Energy Spectroscopy Instrument (DESI) survey where they have revealed the effects of baryon acoustic oscillations (BAO). In order to fit the correlation functions to a physical model and thereby constrain cosmological parameters, it is necessary to take into account the effects of fitting the observed spectra to a…