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Denis Erkal

@derkal.bsky.social
536 followers 255 following 126 posts

Astrophysicist working on dark matter, near-field cosmology, and galaxy formation. All opinions are my own. He/him.

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Denis Erkal @derkal.bsky.social · 08/09/2026
See openai.com/index/navier... for OpenAI’s description of how they solved the problem. What can we do in Astro with tools like this?🧪☄️
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Denis Erkal @derkal.bsky.social · 08/09/2026
Holy forking shit. This is seriously impressive. Some controversy here since Levent Alpöge and Tristan Buckmaster solved this problem with AI as well (see mastodon.social/@tristanbuck...) and their solution has been fed into Codex. But either way, amazing what humans with AI can do!🧪☄️
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Denis Erkal @derkal.bsky.social · 23/07/2026
One week left to apply for this position on stellar streams. Happy to answer any questions so please let me know! aas.org/jobregister/...
aas.org
Research Fellow in Stellar Streams | American Astronomical Society
The University of Surrey is a global community of ideas and people, dedicated to life-changing education and research.  We are ambitious and have a bold vision of what we want to achieve - shaping our...
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Oliver Newton @musicalneutron.bsky.social · 14/07/2026
Come and work at Surrey! 😀
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Denis Erkal @derkal.bsky.social · 14/07/2026
And now the AAS job link: aas.org/jobregister/.... Please let me know if you have any questions about the position! 🔭☄️🧪
aas.org
Research Fellow in Stellar Streams | American Astronomical Society
The University of Surrey is a global community of ideas and people, dedicated to life-changing education and research.  We are ambitious and have a bold vision of what we want to achieve - shaping our...
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Michelle Collins @runningastronomer.bsky.social · 10/07/2026
A great opportunity to come work with Denis, Eugene and the Surrey Astro team! 🧪☄️🔭
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Denis Erkal @derkal.bsky.social · 10/07/2026
Interested in a 3 year postdoc working on stellar streams and dark matter? Come join our amazing Astro group in Surrey to work with me and Eugene Vasiliev. Details here and the deadline is July 30th. Let me know if you have any questions! jobs.surrey.ac.uk/vacancy.aspx... 🧪🔭☄️
jobs.surrey.ac.uk
Job Vacancy at the University of Surrey: Research Fellow in Stellar Streams
The University of Surrey is a global community of ideas and people, dedicated to life-changing education and research. We are ambitious and have a bold vision of what we want to achieve - shaping ours...
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Denis Erkal @derkal.bsky.social · 29/06/2026
Interested in working on stellar streams in the UK? I’ll be posting a 3 year postdoc position to work with me and Eugene Vasiliev on measuring dark matter subhalo properties with streams in a few days. Interviews will be in early August with a start date of October 1st. 🧪☄️
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Denis Erkal @derkal.bsky.social · 24/06/2026
Thanks Emily! It was great to have you over!
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Emily Hunt @emily.space · 24/06/2026
The group in Surrey is absolutely lovely (I visited them last month) so I can highly recommend them!
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Payel Das @payeldas.bsky.social · 24/06/2026
Want to join Surrey Astro? Get in touch if you want to learn more.
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Denis Erkal @derkal.bsky.social · 15/06/2026
Interested in applying for Astro fellowships in the UK? Come to Surrey! We are a fun group and will help you hone your application. Our deadline for ERF/URF consideration is July 8th. For more details of all the fellowships and how to contact us, see www.surrey.ac.uk/astrophysics... 🔭☄️
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Denis Erkal @derkal.bsky.social · 11/06/2026
Here’s our press release about Arrakihs! Lots of cool science will hopefully come out of it and I’m especially excited about what can be done with the long streams it will detect. 🔭☄️🧪 www.surrey.ac.uk/news/esa-off...
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Denis Erkal @derkal.bsky.social · 10/06/2026
Forgot the tags! 🔭☄️🧪
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Denis Erkal @derkal.bsky.social · 10/06/2026
The Arrakihs mission has been adopted as ESA's next F-class mission, with an expected launch in 2030! It will look at the low surface brightness outskirts of 80 Milky Way-like galaxies. www.esa.int/Science_Expl...
esa.int
ESA adopts galactic archaeology mission Arrakihs
The European Space Agency’s (ESA) Science Programme Committee has adopted the Arrakihs mission. Planned for launch by the end of 2030, Arrakihs will capture the faint light from nearby galaxy haloes. ...
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Laura Lopez @ohdearz.bsky.social · 13/11/2025
Honored to receive the 2026 American Physical Society Edward A. Bouchet Award! To see how the DEI ban in Ohio influences our university, please see the OSU announcement of the award (left) vs the actual APS citation for the award (right).
Lopez receives physics award
Laura Lopez, a professor in the Department of Astronomy, is the recipient of the 2026 Edward A. Bouchet Award from the American Physical Society. The award honors Lopez’s pioneering contributions to X-ray astronomy, as well as her transformative leadership of mentoring programs for undergraduates, graduate students and postdocs.Laura A. Lopez, The Ohio State University
2026 recipient, Edward A. Bouchet Award
For pioneering contributions to X-ray astronomy, including foundational studies of supernova remnants, compact objects, and stellar feedback in galaxies, and for transformative leadership in advancing equity and inclusion in physics through innovative mentorship programs, national advocacy, and unwavering support for students from historically marginalized communities.
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Denis Erkal @derkal.bsky.social · 04/11/2025
That sounds like fun! Nice demonstration!
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NSF–DOE Rubin Observatory @rubinobservatory.org · 24/10/2025
We come with receipts🧾 Tidal tails are cosmic “receipts” of galactic drama, showing who collided with whom. Rubin's camera is sharp enough to catch wind of even the faintest intergalactic tea. No need to worry about "pics or it didn't happen" with Rubin keeping a close eye 😎 🔭🧪
A sprawling field of galaxies fills the deep black of space, dotted with glowing stars and colorful smudges of light. Near the top, a smooth golden elliptical galaxy glows like polished stone, linked by delicate, taffy-like streams of stars to nearby galaxies below—evidence of ancient cosmic collisions.
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Denis Erkal @derkal.bsky.social · 10/10/2025
Looking forward to it. Just bought a signed edition in the UK! Loved the Dandelion Dynasty!
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Marcel S. Pawlowski @8minutesold.bsky.social · 09/10/2025
Paper day! My PhD student Mariana Júlio, with @readdark.bsky.social, @pengfeili.bsky.social and others, studies the internal dynamics of dwarf galaxies and finds they don't agree with the Radial Acceleration Relation, challenging the dark matter alternative MOND. arxiv.org/abs/2510.06905 🔭☄️🧪 1/7
arxiv.org
The radial acceleration relation at the EDGE of galaxy formation: testing its universality in low-mass dwarf galaxies
A tight correlation between the baryonic and observed acceleration of galaxies has been reported over a wide range of mass ($10^8 < M_{\rm bar}/{\rm M}_\odot < 10^{11}$) - the Radial Acceleration Rela...
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Denis Erkal @derkal.bsky.social · 30/09/2025
4MOST’s social media account is live! First light expected on October 21st! (1pm UK time) 🔭🧪
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Michael Merrifield @astromikemerri.bsky.social · 20/09/2025
Let us name those who should take responsibility for this situation. The senior management of universities failed to negotiate a sustainable system of funding, and then sleep-walked into mess. But will they be held accountable? Of course not. www.theguardian.com/education/20...
theguardian.com
Quarter of UK university physics departments at risk of closing, survey finds
Four out of five making staff cuts as physicists say findings are ‘great concern’ for UK’s leadership in important areas
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Denis Erkal @derkal.bsky.social · 03/09/2025
Sorry to hear!
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Denis Erkal @derkal.bsky.social · 03/09/2025
Why? Politics in the state or something more specific?
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Denis Erkal @derkal.bsky.social · 22/08/2025
Here’s the Cygnus loop with a Seestar S50. It’s so big that one mosaic won’t fit it so I stitched two of them together. The total exposure is about 4 hours. It would be cool to go even wider and deeper. 🔭
Picture of the Cygnus loop showing lots of stars and thin clouds of gas which came from a supernova explosion
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Stephen Green @stephenrgreen.bsky.social · 17/08/2025
@aircanada.bsky.social
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Stephen Green @stephenrgreen.bsky.social · 17/08/2025
Stranded in Italy thanks to Air Canada. They say by email that they can't find any flights in the next three days and offer a refund -- ignoring EU 261/2004 regulations that they have to rebook on *any* airline. They do not answer the phone. AC has absolute contempt for its customers and employees.
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Denis Erkal @derkal.bsky.social · 04/08/2025
That would be cool! I agree, I was thinking of a by-eye type pointing given the beam width.
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The StarXiv ✨ podcast @starxiv.bsky.social · 04/08/2025
Episode 17 has dropped! Tune in to hear Payel & Michelle talk about about a dark matter subhalo detection, the problem(s) with super massive black holes, massive star clusters in the Sparkler, speedy white dwarfs and more! 🔭☄️ starxiv.com/2025/08/04/e...
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Denis Erkal @derkal.bsky.social · 04/08/2025
Yes, it’s super annoying since this used to be very useful. The issue is it thinks 3e19m is ~56 kpc instead of ~1 kpc but who knows what other units are/will be wrong. Maybe they’ve started using AI for their units?
Screen shot of Google search for (3e19m)/(1 kpc) which gives an answer of 55.7 instead of the correct answer of 0.97
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Denis Erkal @derkal.bsky.social · 03/08/2025
That’s awesome! I was looking to make something like this for outreach. That’s impressively cheap… I’ll be very curious to hear how you get on with it. What do you plan to do for determining where you’re pointing the antenna?
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Denis Erkal @derkal.bsky.social · 24/07/2025
Anyone else notice any weird unit issues with Google lately? (3e19 m)/(1 kpc) gives 55.7 instead of ~1. Not good if you like using Google for quick unit conversions 🔭
Screen shot of a Google search showing (3e19 m)/(1 kpc) gives 55.7
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Michele Bannister @astrokiwi.bsky.social · 02/07/2025
New potential interstellar object in the South: 168 hr arc but e already 9+/-1. H=11. Follow-up encouraged! 🔭
cneos.jpl.nasa.gov
Scout: NEOCP Hazard Assessment
NASA's Near-Earth Object (NEO) web-site. Data related to Earth impact risk, close-approaches, and much more.
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Paul McMillan @mcmillan-astro.bsky.social · 30/06/2025
Non-hot take: The "AI will kill us" discourse was a distraction from the real problem: it removes the young end of the skilled knowledge workforce. They are harder to train, because AI can do it for them. They can't get jobs, because AI can do it for their bosses. www.theguardian.com/business/202...
theguardian.com
Number of new UK entry-level jobs has dived since ChatGPT launch – research
Vacancies for graduate jobs, apprenticeships, internships and junior jobs with no degree requirement have dropped 32%, Adzuna finds
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Denis Erkal @derkal.bsky.social · 26/06/2025
I didn’t mean to trash talk LSST, just that even with this initial processing and without stretching it’s already close to what you had so it’s already pretty good. I look forward to how deep it can be pushed!
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Denis Erkal @derkal.bsky.social · 26/06/2025
Come join us at Surrey! Please get in touch with questions on any of the fellowships (junior to senior), and if you're interested but not sure what you're eligible for, contact me. 🔭
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Denis Erkal @derkal.bsky.social · 25/06/2025
Do you know if the processing was optimized for LSB features or was it the standard pipeline? By eye the depth doesn’t seem that different from your Mihos+2017 paper
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Denis Erkal @derkal.bsky.social · 25/06/2025
Very nice @chrismihos.bsky.social! Do you have a sense of the surface brightness limits of Rubin given your previous work?
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Denis Erkal @derkal.bsky.social · 23/06/2025
Wow, look at that increase in depth!
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NSF–DOE Rubin Observatory @rubinobservatory.org · 23/06/2025
Introducing...your sneak peek at the cosmos captured by NSF–DOE Vera C. Rubin Observatory! Can you guess these regions of sky? This is just a small peek...join us at 11am US EDT for your full First Look at how Rubin will #CaptureTheCosmos! 🔭🧪 #RubinFirstLook ls.st/rubin-first-look-livestream
A sprawling, textured field of galaxies scattered across the deep black of space. It is filled with the delicate smudges and glowing cores of galaxies of many shapes, sizes and colors, as well as the bright multi-colored points of stars. The image focuses on a collection of interacting galaxies connected by delicate streams of stars. At top center lies a large elliptical galaxy that is dense and smooth, like a polished stone glowing with golden light. Like delicate spider silk or stretched taffy, these stellar bridges link the large elliptical to the few larger galaxies beneath, evidence of past collisions.

All throughout the image, thousands of galaxies gather in clusters or are spread throughout, like glittering gems strewn on a table. Some are sharp-edged and spiral, like coiled ribbons; others round and diffuse, like polished pebbles. Still others are just smudges of various colors against the black of space. The background is peppered with pinpoint stars in reds, yellows, and blues, crisp against the velvet black. A cosmic tapestry of glowing tan and pink gas clouds with dark dust lanes. In the upper right, the Trifid Nebula resembles a small flower in space. Its soft, pinkish gas petals are surrounded by blue gas, and streaked with dark, finger-like veins of dust that divide it into three parts. It radiates a gentle, misty glow, diffuse and soft like the warmth of breath on a cold hand. To the lower left, the much larger Lagoon Nebula stretches wide like a churning sea of magenta gas, with bright blue, knotted clumps sprinkled throughout where new stars are born. Both nebulae are embedded in a soft tan backdrop of gas that is brighter on the left than on the right, etched with dark tendrils of dust and sprinkled with the pinpricks of millions of stars.A sprawling, textured field of galaxies scattered across the deep black of space. It is filled with the delicate smudges and glowing cores of galaxies of many shapes, sizes and colors, as well as the bright multi-colored points of stars. To the lower left is a region filled with the hundreds of golden glittering gems of a distant galaxy cluster. In the foreground, below and right of center, two blue spiral galaxies look like eyes beneath the entangled mass of a triple galaxy merger in the upper right. A few bright blue points of foreground stars pierce the glittering tapestry.

All throughout the image, thousands of galaxies gather in clusters or are spread throughout, like glittering gems strewn on a table. Some are sharp-edged and spiral, like coiled ribbons; others round and diffuse, like polished pebbles. Still others are just smudges of various colors against the black of space. The background is peppered with pinpoint stars in reds, yellows, and blues, crisp against the velvet black.
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Denis Erkal @derkal.bsky.social · 17/06/2025
Considering a senior UK fellowship (ERF, URF)? We have a great group at Surrey and our internal deadline for the ERF is July 8th. We are looking for a light-touch application: CV and 1 page research statement. I'm the contact person, so send questions/material to me www.ukri.org/what-we-do/d... 🔭
ukri.org
Ernest Rutherford Fellowships
Ernest Rutherford Fellowships (ERF) enables early career researchers with clear leadership potential to establish a strong, independent research programme. They encourage talented researchers in UK un...
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Denis Erkal @derkal.bsky.social · 01/06/2025
Really good set of slides about how Nazi scientists did very little to combat the Nazi party
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Denis Erkal @derkal.bsky.social · 28/05/2025
When I’ve asked chatgpt technical questions, it frequently makes subtle mistakes that only an expert would know are wrong. If an expert is needed to fix its output, I’d argue it can’t do anything of importance on its own.
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Denis Erkal @derkal.bsky.social · 24/05/2025
Yes! If you’re ever in London please let me know!
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Denis Erkal @derkal.bsky.social · 22/05/2025
Congrats on the book Adam! I’ve enjoyed all your interviews I’ve read about it. I also bought it and look forward to reading it!
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Chris Lintott @chrislintott.bsky.social · 17/04/2025
An astonishing headline reporting on new observations from a team led to Nikku Madhusudhan claims they’ve found ‘hints of life’ on a planet orbiting a dwarf star some 124 light years away. What’s going on? (1/n) www.bbc.co.uk/news/article... 🔭 🧪
bbc.co.uk
Promising hints of life found on distant planet K2-18b
Scientists find new but tentative evidence that a faraway world orbiting another star may be home to life.
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Denis Erkal @derkal.bsky.social · 16/04/2025
That would be interesting. Would it be in the evening?
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Peter Coles 🏳️‍🌈 🏳️‍⚧️ 🇮🇪 @telescoper.bsky.social · 13/04/2025
Bullying at Cambridge University There's a long article in today's Observer about bullying at Cambridge University, which I encourage you to read, as it shows that the scale of the bullying problem in Cambridge is very worrying. I'll just emphasize a couple of things here. One is that Cambridge…
telescoper.blog
Bullying at Cambridge University
There's a long article in today's Observer about bullying at Cambridge University, which I encourage you to read, as it shows that the scale of the bullying problem in Cambridge is very worrying. I'll just emphasize a couple of things here. One is that Cambridge University is due to elect a new Chancellor this year and, as is mentioned in the Observer, Professor Wyn Evans of the Institute of Astronomy is planning to stand as a candidate on an anti-bullying platform.
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Denis Erkal @derkal.bsky.social · 12/04/2025
That’s a great target! Was this with a mosaic or just the normal field of view?
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Denis Erkal @derkal.bsky.social · 12/04/2025
I tried to image the Palomar 5 globular cluster with a Seestar S50 for 3 hours. The cluster is the middle of this image and some of the faintest stars have Gaia G mags of ~17.5 and the right proper motions to be Pal 5 stars. 🔭
Seestar image of Palomar 5 showing a few bright stars and many faint stars
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