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#nova

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Weekly Update from the Open Journal of Astrophysics – 19/04/2025

It may be the Easter holiday weekend, but it’s still time for the weekly Saturday morning update of papers published at the Open Journal of Astrophysics. Since the last update we have published five new papers, which brings the number in Volume 8 (2025) up to 42 and the total so far published by OJAp up to 277.

In chronological order of publication, the five papers published this week, with their overlays, are as follows. You can click on the images of the overlays to make them larger should you wish to do so.

The first paper to report is “Galaxy Clustering with LSST: Effects of Number Count Bias from Blending” by Benjamin Levine (Stony Brook, NY), Javier Sánchez (STScI, MD), Chihway Chang (Chicago, IL) Anja von der Linden (Stony Brook), Eboni Collins (Dillard, LA), Eric Gawiser (Rutgers, NJ), Katarzyna Krzyżańska (Cornell, NY), Boris Leistedt (Imperial College, UK) on behalf of the LSST Dark Energy Science Collaboration.

This presents a simulation-based study of the effect of source overlaps (blending) on galaxy counts expected for the Vera C. Rubin Legacy Survey of Space and Time (LSST). The paper is in the folder Cosmology and NonGalactic Astrophysics and was published on Monday 14th April 2025. The overlay is here:

 

You can find the officially-accepted version of the paper on arXiv here.

The second paper to announce, published onTuesday 15th April 2025,  “Rapid, strongly magnetized accretion in the zero-net-vertical-flux shearing box” by Jonathan Squire (Otago, New Zealand), Eliot Quataert (Princeton, USA) & Philip F. Hopkins (Caltech, USA). This  paper presents a numerical study of turbulence in a flux shearing box, with discussion of the implications of the results for global accretion disk models and simulations thereof. It was published in the folder High-Energy Astrophysical Phenomena and the overlay is here:

 

You can read the officially accepted version of this paper on arXiv here.

The third paper of the week, published on Wednesday April 16th 2025,   is “DeepDISC-photoz: Deep Learning-Based Photometric Redshift Estimation for Rubin LSST” by Grant Merz (University of Illinois at Urbana-Champaign, USA) and 13 others (all based in the USA) on behalf of the LSST Dark Energy Science Collaboration. This paper describes adding photometric redshift estimation to the DeepDISC framework for classification objects in co-added images for use with the Vera C. Rubin LSST survey. It can be found in the folder Instrumentation and Methods for Astrophysics.

Here is the overlay:

 

You can find the officially accepted version of this paper on arXiv here.

The next one to report is “Multidimensional Nova Simulations with an Extended Buffer and Lower Initial Mixing Temperatures” by Alexander Smith Clark and Michael Zingale (Stony Brook University, NY, USA). This paper presents new computer models of classical novae with improved ability to follow nucleosynthesis in the thermonuclear outburst and better treatment of convective transport. This one was also published on Wednesday 16th April 2025 but in the folder Solar and Stellar Astrophysics.

Here is the overlay:

 

The official published version can be found on the arXiv here.

The last paper of the five published this week is “Measurement of the power spectrum turnover scale from the cross-correlation between CMB lensing and Quaia” by David Alonso (Oxford, UK), Oleksandr Hetmantsev (Kyiv, Ukraine), Giulio Fabbian (Cambridge, UK), Anze Slosar (Brookhaven National Laboratory, USA) and Kate Storey-Fisher (Stanford, USA). This is a discussion of using the spatial correlations of quasars and their cross-correlations with cosmic microwave background lensing data to measure a feature corresponding to the matter-radiation equality scale with consequences for cosmological parameter estimation. It was published on Thursday 17th April 2025 in the folder Cosmology and NonGalactic Astrophysics.

The overlay is here:

You can find the officially accepted version on arXiv here.

That’s all the papers for this week. I’ll just add that, although there have been weeks before in which we have published five or more papers, we still haven’t managed to have a week on which we’ve published a paper on every weekday. This week we had two on Wednesday 16th but didn’t have any yesterday (Friday).

#Astronomy #Nova #BlazeStar

Es gibt einen "Blaze Star" -> T Coronae Borealis (T CrB)

Sie ist vm Typ her eine wiederkehrende Nova (Recurrent Nova). Ihr findet sie im Sternbild Corona Borealis (Nördliche Krone)

Und jetzt kommt es!
Sie wird etwa alle 80 Jahre plötzlich hell (zu einer Nova) – zuletzt 1946, vorher 1866.
Das bedeutet, wir könnten jeden Tag im Jahr 2025 (okay, könnte auch nächstes Jahr erst passieren - die Vorhersagen sind etwas vage) einen neuen Stern am Himmel entdecken!
Er geht nun im April wenige Stunden nach Sonnenuntergang am ostnordöstlichen Himmel auf und ist so lichtschwach, dass es nur mit sehr lichtstarken Teleskopen gesehen werden könnte.
Beim Blaze Star handelt sich um ein Doppelsternsystem mit einem Weißen Zwerg, der Materie von seinem Begleitstern (hier ein Roter Riese) absaugt und wenn genug Wasserstoff auf der Oberfläche des Weißen Zwergs angesammelt ist, zündet eine thermonukleare Explosion – das ist dann die Nova.

Wenn der Stern zur Nova wird, wird er so hell wie der Polarstern ungefähr und einige Tage zu sehen sein.

Macht ein Foto von der Nördlichen Krone (Corona Borealis) und dann schaut alle paar Tage, ob da ein Punkt ist, der auf dem Foto nicht war.

Und ihr seht eine Nova!

The initial nova-core driver stub was merged to #Linux mainline for #LinuxKernel 6.15[1].

#Nova is going to be a #kernel driver for #Nvidia's modern GPUs written in #Rustlang. It is the successor of the #Nouveau kernel driver and serve as base for drivers like #NVK.

The core driver stub is not really useful for anything yet. But that should change soon – and I guess will be the turning point that'll sell #Rust for Linux to the world. 🥳

[1] git.kernel.org/torvalds/c/54e6 and git.kernel.org/torvalds/c/b287

git.kernel.orggpu: nova-core: add initial driver stub - kernel/git/torvalds/linux.git - Linux kernel source tree

So in T CrB system, both the red giant and the white dwarf can trigger nova events but can we talk about how the red giant is still standing (with the exception that it does not destroy the white dwarf)? 🤯 This is just mind-boggling.

"T CrB is actually even more special than that, because it is one of only 11 known "recurrent" novas, which are seen to go nova repeatedly, with gaps of less than 100 years between explosions."

space.com/the-universe/stars/h

Space · Hold onto your hats! Is the 'blaze star' T Corona Borealis about to go boom?By Keith Cooper
Replied in thread

@lyte Es ist noch ein Bissen komplizierter.
Ich fand diese Artikel sehr erhellend, gerade was #vegan Produkte angeht.
Von den Auswirkungen die Cola, Bier und Wurst hat, wird selten gesprochen.
Beitrag von Prof. Dr. rer. nat. Martin Smollich vom Institut für Ernährungsmedizin in Lübeck zur oft absurden Diskussion um hochverarbeitete Lebensmittel...

Hochverarbeitete Lebensmittel: Sie sind nicht alle gleich.
Hochverarbeitete Lebensmittel (ultraprocessed foods, #UPF) haben einen schlechten Ruf: Angeblich sollen sie allein deshalb „ungesund“ sein, weil sie hochverarbeitet sind – unabhängig vom Nährstoff- oder Kaloriengehalt. Ernährungswissenschaftlich ist das ziemlich absurd.
vegconomist.de/food-and-bevera
Daniel Wefers, Professor für Lebensmittelchemie an der Martin-Luther-Universität Halle-Wittenberg.
archive.ph/2024.11.02-064855/h
Wenn dich das Thema näher interessiert, dann schau wie Klassifikation #NOVA erfunden wurden.
Mit Wissenschaft nach heutigem Stand hat das nichts zu tun

I picked up this paperback of Samuel R. Delany’s “Nova” back in the early 2000s when I was attempting to read my way through David Pringle’s list of the 100 greatest science fiction novels (pre-1984), and I kinda want to revisit it. Despite Delany’s impeccable reputation I can’t help but picture STAR TREK Space Hippies when envisioning his cast. Would he mind? #1960s #Books #Nova #SamuelRDelany #ScienceFiction

Einige Beispiele für WENIG verarbeitete Lebensmittel (gem. #NOVA-Klassifikation) mit SCHLECHTEN Nährwertprofilen:

#Honig
#Zucker
#Butter & #Käse
#Fruchtsaft
#Serranoschinken
gesalzene Nüsse

Einige Beispiele für HOCHverarbeitete Lebensmittel #UPF (gem. NOVA-Klassifikation) mit GUTEN Nährwertprofilen:

#Vollkornbrot
Vegane #Fleischalternativen
#Vollkornmüsli mit Flakes
nährstoffangereicherte #Soja- und #Haferdrinks
#Gemüseaufstrich
geräucherter #Tofu

Und mit was wirbt der #Bauernverband?
#Hülsenfrüchte, #Nüsse, #Vollkorn und #Gemüse?
Noooooin!
#Tierindustrie #Klimakatastrophe #Rinder #Kälber #Tierquälerei #Klima #landwirtschaft