Euclid: Quick Data Release (Q1) -- Exploring the detailed visual morphology of galaxies in clusters
Mas-Buitrago, Kruk, O'Ryan, Nardone, La Marca, Awad, Baes, Fossati, G\'eron, Ghaffari, Girardi, Lintott, Sorce, Altieri, Durret, Pettorino, Irureta-Goyena, Simmons, Reerink, S\'anchez, Knapen, Shankar, Duran-Camacho, P\'erez-Mart\'inez, Walmsley, Auricchio, Baccigalupi, Baldi, Bardelli, Battaglia, Biviano, Bolzonella, Bonchi, Branchini, Brescia, Brinchmann, Camera, Ca\~nas-Herrera, Capobianco, Carbone, Carretero, Castellano, Castignani, Cavuoti, Cimatti, Colodro-Conde, Congedo, Conselice, Conversi, Copin, Costille, Courbin, Courtois, Cropper, Degaudenzi, De Lucia, Dole, Dubath, Dupac, Dusini, Ealet, Fabricius, Farina, Farinelli, Ferriol, Fosalba, Fotopoulou, Frailis, Franceschi, Fumana, Galeotta, George, Gillis, Giocoli, G\'omez-Alvarez, Gracia-Carpio, Grazian, Grupp, Gwyn, Holmes, Hook, Hormuth, Hornstrup, Huertas-Company, Jahnke, Jhabvala, Joachimi, Kermiche, Kiessling, Kubik, K\"ummel, Kunz, Kurki-Suonio, Le Brun, Ligori, Lilje, Lindholm, Lloro, Mainetti, Mansutti, Marggraf, Martinelli, Martinet, Marulli, Massey, Maurogordato, Medinaceli, Melchior, Meneghetti, Merlin, Meylan, Mora, Moresco, Moscardini, Munari, Neissner, Niemi, Nightingale, Padilla, Paltani, Pasian, Pedersen, Percival, Pezzotta, Pires, Polenta, Poncet, Popa, Pozzetti, Raison, Renzi, Rhodes, Riccio, Romelli, Roncarelli, Rusholme, Saglia, Sakr, S\'anchez, Sapone, Sartoris, Schneider, Schrabback, Scodeggio, Secroun, Sihvola, Simon, Sirignano, Sirri, Tallada-Cresp\'{i}, Taylor, Teplitz, Tereno, Tessore, Toft, Toledo-Moreo, Torradeflot, Tutusaus, Valiviita, Vassallo, Kleijn, Veropalumbo, Wang, Weller, Zacchei, Zamorani, Zerbi, Zucca, Macias-Perez, Sereno
https://arxiv.org/abs/2609.08962 https://arxiv.org/pdf/2609.08962 https://arxiv.org/html/2609.08962
arXiv:2609.08962v1 Announce Type: new
Abstract: Galaxy clusters provide unique laboratories for studying environmental effects on galaxy evolution. The morphology--density ($T$--$\Sigma$) and morphology--cluster-centric radius ($T$--$R$) relations trace how galaxy morphology is influenced by the environment, but previous studies at intermediate redshifts have been limited in both sample size and radial coverage. We use the Euclid Quick Data Release 1 (Q1) visual morphology catalogue to measure the $T$--$\Sigma$ and $T$--$R$ relations for smooth, featured-or-disc, and barred galaxies in known clusters at $0.2\leq z\leq 0.5$, extending this analysis to large cluster-centric distances ($3 R_{500c}$) and studying their dependence on stellar mass. Using photometric redshifts and stellar masses provided by Euclid, we identify 1754 cluster members within $1.5 R_{500c}$, distributed across 71 clusters. We classify the identified galaxies as smooth, featured-or-disc, or barred using the predicted vote fractions provided by the Zoobot deep learning foundation model in the Q1 visual morphology catalogue. We confirm the $T$--$\Sigma$ relation in all the stellar mass ranges studied, with a stronger influence of the cluster environment on galaxy morphology in the densest parts of the cluster and closer to the cluster centre. Beyond $1.5 R_{500c}$, the morphological segregation weakens, with featured-or-disc galaxies overtaking smooth galaxies at the lowest densities, consistent with the growing contribution of field interlopers in the cluster outskirts. For barred galaxies, we find a tentative decline of the bar fraction toward lower densities that is most pronounced for the most massive galaxies. In conclusion, our results show that the cluster environment drives a progressive transformation of galaxy morphology, with the loss of disc structure becoming more pronounced towards the cluster core, where environmental processes act most efficiently.
toXiv_bot_toot

📝 Droning on about drones

September 29, 2026
Three years ago I got a DJI Mini 3 Pro for my birthday. Flying it around and getting aerial pictures is great fun. Lately, though, it mostly stays in its bag. This is about why.
It's tiny. The camera is decent: a 1/1.3-inch sensor behind an f/1.7 lens, which is a big sensor for something this size. It has 48 megapixels through the magic of marketing, which means it's 12 megapixels that get upscaled. It does RAW, and 4K video. It has a fancy gimbal head that is surprisingly competent at keeping the camera stable. The drone can autonomously follow a subject, circle a point, or fly preset moves. Handy if you're a narcissist or just not as comfortable with the controls yet.
DJI promises 34 minutes in the air, probably in a vacuum. Real flights, with actual air and wind resistance are around 20 minutes. Range is 8 kilometres, which sounds unrealistic, but probably refers to the antenna. Anyway in the Netherlands you are obliged to keep the drone in your line of sight. Obstacle sensors look forward, back and down, and freak out whenever I get close to Big Hard Things.
And it weighs under 249 grams, which is the whole point of the Mini line. Under 250 grams it flies in the A1 subcategory, the most relaxed one in the EU. You can fly near and even over people, as long as it isn't a crowd. No exam either, just an operator number from the RDW, the Dutch vehicle authority, stuck on the drone. On paper, it's about as free as flying gets. Except all the restrictions that apply anyway because it has a camera. 
It looks easy. It isn't. The Mini holds its position on GPS, so hovering takes no effort at all. Everything else takes practice. Two sticks: the left one handles height and turning, the right one moves you forward, back and sideways. A wheel tilts the camera. A smooth shot usually means using three of those at once, gently, while the drone drifts in the wind. At 249 grams it doesn't take much wind to destabilize it.
Then there's orientation. When the drone faces you, everything is mirrored: left is right, forward is back. At a hundred metres it's a dot, and you can't tell whether it's clearing that tree or about to hit it. The obstacle sensors don't look sideways, so sideways is your problem. And you're supposed to keep your eyes on the drone, while the shot you're making is on the screen in your hands.
Practice is exactly what I'm not getting, and the reason starts at my own front door. 
My home is squeezed in between three no-fly zones. De Horsten, the royal estate, lies in prohibited area EHP-26, the same rectangle of closed airspace that covers Huis ten Bosch, Noordeinde and the Binnenhof. It runs from the ground to about 600 metres, and no drone gets an exemption, whatever it weighs. The King moved out in 2019; the no-fly zone didn't. The other one is Valkenburg, the old naval air base. It closed back in 2006, and the province turned part of it into a test airport for professional drones, called Unmanned Valley. Whether there's still a restricted circle around it depends on which map you ask. Since at least 2022, the official aviation chart has shown one and the official drone map hasn't.
The drone map around Wassenaar. The pink rectangle is EHP-26, with De Horsten at the bottom. The dunes are on the left, and the dots mark the old airfield at Valkenburg.
That's the real problem: nobody can tell you exactly where the lines are. The government points you to two maps, and both say you can't derive any rights from them. The borders don't follow a street or a fence, either. It's a line on a map, and you're standing in a field trying to work out which side of it you're on. And where the air is free, the ground may not be: Dunea, the water company that runs the water extraction in the dunes, simply bans drones in Meijendel.
Then there's the mood. Last year drones turned up over airports and air bases across Europe. Russia is the usual suspect, though whose they are hardly matters. Do you really want to have your drone shot out of the sky and have an inspiring conversation with an arrest team?
Probably not. The police don't publish how many drone fines they hand out, and an investigation counted thousands of illegal flights over The Hague every year. Nobody patrols the Wassenaar wastelands looking for a 249-gram drone.
Then again, nobody has to. Drones under 250 grams are exempt from the EU's Remote ID. But on my generation of drones, DJI's own signal broadcasts the drone's position and the pilot's, unencrypted.
The fines themselves aren't dramatic: €250 for flying in a no-fly zone, €300 over a crowd, €350 near vital infrastructure and €500 for getting in the way of emergency services. They stack, though, and the drone usually gets seized as well.
In a village like Wassenaar, the likeliest detection system is the neighbour. Most people are uneasy about drones, mainly because of privacy. One of my colleagues, who lives in a big city, proudly claims to shoot illegal drones out of the sky with a slingshot.
Even a perfectly legal flight comes with a fair chance that someone walks over to argue about it. That's an argument I'd rather not have. It's supposed to be fun.
The obvious way out is to take it on holiday. I mostly go to Germany, the Czech Republic and Slovakia, and surely somewhere out there is a field with room for 249 grams of drone. My Dutch registration is valid everywhere in the EU, so how hard can it be?
Quite hard, it turns out. The EU only sets the basics, and every country adds its own layer on top. Zones, its own map app, its own list of special permissions. Nature parks, castles and towns add theirs. And the rules move: the Czech Republic introduced a whole new zone system only last year. 
Germany wants proof of insurance in your pocket, which I don't need in the Netherlands. The Czech Republic wants a flight plan in its app before almost any flight near a town, road or railway. Slovakia doesn't ask for insurance, but most of its mountain areas are off limits on principle, so that actually limits what there is to take pictures of in the first place.
Read all that back and you'd think I should sell it. I won't. Because when it does go up, it's still awesome. A few seconds after take-off the ground turns into a map, and places you walk past every day look like somewhere you've never been. None of my other cameras can do that. So hopefully I will be more successful at motivating myself to keep trying in the near future. 
Please feel free to add any tips for drone photography you might have, and I may use them to rekindle my interest in the hobby.
#Blog #Article #Drones #Gear #Photography #Travel #Wassenaar

Spent the weekend with a few friends at Beautiful Days festival out in Exeter, which is the one that The Levellers run and fill with mostly 90s bands.
So lots of old men on stage and in the audience. Including me. It's me.
Weather was mostly good as you'd like. Not quite as too-hot as it's been lately and only The Undertones made the weather gods angry. After the end of their wet set the double rainbow promising no more rain proved a true promise.
Mostly either old things, or things I'd never heard of, because I haven't really paid attention to music since the 1900s.
Young new folks seemed to be mostly half Welsh, and included Gwenno who was beautiful in her cat-mask and sang a song in old Cornish about cheese, Gina Larner who was playing country rock with her beautiful sparkly country boots, Trampoline who had one guitarist replaced by a cardboard cut-out for some reason I missed and are from Swansea, and Ben Brown whose rider included a lacy fancy dress and seizable stick - his merch song as he danced around and stripped off the ten tee-shirts he sells and was wearing all at once for the first half apparently was memorable.
Old folks on stage included Billy Brag, who is so right-on and woke you wonder why all the other musicians are so apolitical. Madness, who have banger after banger but lack some energy now they're so old. The Undertones, who angered god by still singing about Teenage Kicks in their sixties, Super Furries who, inexplicably drew a much smaller crowd as people watched the Proclaimers instead I guess. The Divine Comedy, who acts very sophisticated mixing cocktails on stage. Also The Wonder Stuff who still mock their own audience but got us all nostalgic and emotional, they're loved and welcome in my home too.
And of course the Levellers who fill the field because they don't put anyone else up at the same time as them and so WAY up on the hill behind the ice cream van where you can't really see but at least you can move.
The Nanaz are both old and new, in that they've only been playing for a few years and yet are already each as old as the grandad bands playing here singing songs about menopause and being told they used to be beautiful.
It's a lovely smallish festival, big enough to have choices and headliners, but small enough to walk across, with hardly any bandwidth and which is too far away really. That drive home was very tedious.
Bravo though though. Hope it outlasts the Levellers, and both keep going for decades more. Hope to be back.
#music #festival #uk #beautifulDays