Tootfinder

Hubble Space Telescope Observations of the Interstellar Interloper 3I/ATLAS: #Interstellar Comet, Hubble Makes Size Estimate: https://science.nasa.gov/missions/hubble/as-nasa-missions-study-interstellar-comet-hubble-makes-size-estimate/ and https://www.esa.int/ESA_Multimedia/Images/2025/08/Hubble_sizes_up_rare_interstellar_comet (which is 5.6 km > nucleus diameter > 320 m, so we still don't know much here).

Carnegie Supernova Project - Fast-Declining Type Ia Supernovae as Cosmological Distance Indicators: #HubbleConstant is ... 75!

Hot #cosmology papers ...
The Perfect Host - JWST Cepheid Observations in a Background-Free SN Ia Host Confirm No Bias in Hubble-Constant Measurements: https://arxiv.org/abs/2509.01667
Glimmers in the Cosmic Dawn - On the Photometrically Determined Black Hole Mass to Stellar Mass Relation Across Cosmic Time: https://arxiv.org/abs/2508.15905
The coherent satellite velocity field around the interacting spiral galaxy pair NGC5713/19 - signature of two galaxy groups merging: https://academic.oup.com/mnras/article/542/1/62/8215207?login=false
Looking beyond lambda: https://arxiv.org/abs/2509.00359

The CosmoVerse White Paper - Addressing observational tensions in cosmology with systematics and fundamental physics: #HubbleTension debate: https://physicsworld.com/a/cosmic-conflict-continues-new-data-fuel-the-hubble-tension-debate/. Also A Tale of Many H0: https://www.annualreviews.org/content/journals/10.1146/annurev-astro-052622-033813

35 years ago #OTD the #Hubble Space Telescope with its mishappen optics took this image of #Saturn - which could be sharpened a lot mathematically (as the paper https://articles.adsabs.harvard.edu/full/1991ApJ...369L..51W later described) since the object was so bright. It's being said that this one image was used by NASA to convince key U.S. politicians that the broken satellite still had some life in it ... and so it was, for 35 years now!

Breaking the Baryon Density$\unicode{x2013}$Hubble Constant Degeneracy in Fast Radio Burst Applications with Associated Gravitational Waves
Joscha N. Jahns-Schindler, Laura G. Spitler
https://arxiv.org/abs/2508.14434

Breaking the Baryon Density$\unicode{x2013}$Hubble Constant Degeneracy in Fast Radio Burst Applications with Associated Gravitational Waves
Fast Radio Bursts (FRBs) are a unique probe of the cosmos, owing to dispersion caused by free electrons in the intergalactic medium (IGM). Two of the main quantities of interest are degenerate: the density of matter $Ω_\mathrm{b}f_\mathrm{d}$ outside of galaxies and the Hubble constant $H_0$. Here, we present a new possibility of breaking the degeneracy without invoking early Universe priors on $Ω_\mathrm{b}$. Assuming some FRBs originate in compact object mergers, the combination of dispersi…

Dusty streaks on the #Moon - fingerprints of multiphase flow instabilities: https://www.nature.com/articles/s41467-025-62001-8 -> Johns Hopkins engineers explain forces that create unusual radiating dust patterns: https://hub.jhu.edu/2025/07/21/lunar-landing-dust-debris/

Just in via #Hubble images of interstellar #comet ATLAS! Also observations with #Rubin have been published in the paper https://arxiv.org/abs/2507.13409 - and in https://groups.io/g/comets-ml/message/33852 the brightness development since May gets analyzed.

A previously unknown regular satellite of #Uranus has been detected in a series of images obtained by the Near-Infrared Camera (NIRCam) onboard the James Webb Space Telescope on 2025 Feb. 2: http://www.cbat.eps.harvard.edu/iau/cbet/005500/CBET005593.txt -> https://science.nasa.gov/blogs/webb/2025/08/19/new-moon-discovered-orbiting-uranus-using-nasas-webb-telescope/ - the object is located at a projected radial distance of 56250 /- 250 km from Uranus' center in the planet's equatorial plane, initial astrometry is consistent with the moon orbiting on a nearly circular orbit with an orbital period 0.402 days, and the observed IR flux from the object indicates a radius of 4 - 5 km, placing it well below the detection threshold of earlier images from Voyager and the Hubble Space Telescope.