Madison Walder

*Taps mic* Is this thing on?

My first first-author paper has finally been published!

If you are like in globular clusters, dwarf galaxies, or a new third object we are calling "Globular Cluster-like Dwarfs" look no further!, we present high resolution simulations where all three emerge naturally🧪🔭

The emergence of globular clusters and globular-cluster-like dwarfs - Nature The results from a state-of-the-art suite of hydrodynamical cosmological zoom-in simulations show how globular clusters naturally emerge in the Standard Cosmology and also reveal the existence of a ne...

Big news! @astroeth.bsky.social has his Nature paper on the Emergence of Globular Clusters out today! His simulations have globulars forming naturally, as well as some cool globular cluster like dwarfs! Check it out! 🔭🧪☄️

www.nature.com/articles/s41...

A graph of the evolution of the dark energy (vertical axis) as a function of time (redshift on the horizontal axis) - showing an offset from the cosmological constant (a flat horizontal line). Here is the figure caption from the paper: FIG. 12. Comparison of the constraints on the equation of state of dark energy using the CPL parametrization and a bin- ning reconstruction approach, using DESI+CMB+DESY5. The solid green line shows the best-fit w(z) based on w0 and wa inference and the green contours around it represent the 68% and 95% confidence intervals. We also show in blue the constraints from the binning approach [47], with the hori- zontal bars indicating the bin width (which is fixed) and the vertical bars representing the 1σ error. Additionally, we in- clude in gray the 1D posterior for each binning parameter. The ΛCDM limit corresponds to the horizontal gray dashed line.

Congrats to @desisurvey.bsky.social - it's looking more & more like dark energy isn't Einstein's cosmological constant! If you've woken up to the news & are searching for the publications, they don't appear to be on arxiv 🤷‍♀️ but they are online. 🔭 #cosmology 🧪
ℹ️: data.desi.lbl.gov/public/paper...

Euclid’s mosaic image (bottom right) superimposed on a Gaia and Planck all-sky map

This mosaic made by ESA’s Euclid space telescopes contains 260 observations collected between 25 March and 8 April 2024. This is 1% of the wide survey that Euclid will capture during six years. In just two weeks, Euclid covered 132 square degrees of the Southern Sky, more than 500 times the area of the full Moon as seen from Earth. The full mosaic is 208 gigapixels.

This image shows an area of the mosaic released by ESA’s Euclid space telescope on 15 October 2024. The area is zoomed in twelve times compared to the large mosaic. In the middle left, spiral galaxy NGC 2188 is visible edge-on at a distance of 25 million light-years. In the top right corner, galaxy cluster Abell 3381 is now clearly noticeable, 678 million light-years away from us.

This image shows an area of the mosaic released by ESA’s Euclid space telescope on 15 October 2024. The area is zoomed in 150 times compared to the large mosaic. On the left of the image, Euclid captured two galaxies (called ESO 364-G035 and G036) that are interacting with each other, 420 million light-years from us. On the right of the image, galaxy cluster Abell 3381 is visible, 678 million light-years away from us.

The European Space Agency's Euclid space telescope is assembling the largest 3D map of the universe ever made.

The first section is now complete. Take a look at what happens when you zoom in... 🧪🔭

www.esa.int/Science_Expl...

Oof it’s been a while since I posted, but for those at #EAS2024, I have a (virtual) talk today at 15:54 CEST in the s7e session! Come along if you want to hear me ramble about how we can use stellar streams to probe the dark matter in galaxies! 🌌 🔭🧪

Great to have a talk on ESA’s Fast mission ARRAKIHS. Small missions get much less attention but deliver awesome science on shorter timescales and in a reasonable budget. #SPIEastro

Oh absolutely, there is definitely a correlation between the amount of time I’ve spent in academia and the degradation of my ability think/communicate coherently

THATS 👏 MY 👏 SUPERVISOR 👏

Shout out to the sun for letting me check this off my bucket list

Perks of moving somewhere greener:

1) the rain makes the green more green™️
2) i am blessed by the presence of these little guys

At Indiana University. Admirable af.

Crazy how this never happened to the preachers verbally assaulting students for wearing yoga pants on college campuses 🤔

We 👏 should 👏 talk 👏 more 👏 about 👏 streams 👏

In this video, Nora Shipp, Postdoctoral fellow at Carnegie Mellon University and Co-convener of the Dark Matter Working Group in the Rubin/LSST Dark Energy S... Rubin Observatory will Reveal Dark Matter’s Ghostly Disruptions of Stellar Streams - YouTube

It's #FeatureFriday! Meet Nora Shipp, stellar streams extraordinaire ✨

Stellar streams are the torn-apart remnants of small galaxies or star clusters around the Milky Way—they hold clues about its history, and the dark matter that surrounds it.

www.youtube.com/watc...

Inferring dark matter subhalo properties from simulated... In the cold dark matter paradigm, our Galaxy is predicted to contain >10000 dark matter subhaloes in the $10^5-10^8M_\odot$ range which should be completely devoid of stars. Stellar streams are...

Very excited to see my student Tariq Hilmi submit this paper https://arxiv.org/abs/2404.02953 with the S5 team. We explored how well we can recover subhalo properties from a realistic stream model. TLDR: we can do it pretty well for a 10^7 Msun perturbed even with present-day observables 1/ 🔭🧪

Yess!! Big congrats to Tariq!! 🎉🎉

A view of the Milky Way supermassive black hole Sagittarius A* in polarized light.

The Event Horizon Telescope has measured the *polarized* radiation from our friendly neighborhood black hole, Sgr A*! Press release: eventhorizontelescope.org/blog/astrono..., papers in next skeet 🔭🧪

Astrobites Statement on the Educational Siege in Gaza The genocide in Gaza demands our attention and our action. As astronomers and members of the global scientific community, we cannot ignore the immense suffering and devastation inflicted upon our c…

From the Astrobites collaboration: The genocide in Gaza demands our attention and our action. As astronomers and members of the global scientific community, we cannot ignore the immense suffering and devastation inflicted upon our colleagues. 🔭

astrobites.org/2024/03/27/a...

Act Now | Save the Chandra X-ray Observatory Ask that Congress #SaveChandra! | The Chandra X-ray Observatory, one of NASA's last Great Observatories, has revolutionized our understanding of the Universe, mapped black holes across cosmic time, ...

“Save Chandra” website now up with explanation of the budgetary threat to this Great Observatory, some necessary corrections regarding current mission capabilities and operating costs, and - most important - ways that you can help. 🧪 🔭 🛰️ Spread widely!

MAGICAL

Absolutely love the colormap for this plot 😍

In the same boat, you’re not alone 💪

oh to be a tiny tree frog in a giant rainforest. no job, no insecurities, only wet.

there are a few fundamental rules that commuters absolutely MUST learn to survive in the UK. The first is to internalise the concept of "keep left" designed to help keep foot traffic efficient in both directions, then do your absolute best to do the exact OPPOSITE.

3 Hubble images covering IC 2574 have been stitched together so you can see the extent of the galaxy. The 23 candidates are highlighted, and they span the whole image. We also show 5 excluded candidates that are much bluer than GCs and could be younger clusters.

Paper alert! My student, Noushin Karim, has been searching for globular clusters around the M81 group dwarf galaxy, IC 2574. She has found 23 candidates, and 1 looks a bit Omega-Cen-like. 🔭🧪 arxiv.org/abs/2402.16955

Oh I love her the colors are so vibrant!

Thanks so much, and me too! 😁

Probing the dark matter haloes of external galaxies with stellar streams Stellar streams have proven to be powerful tools for measuring the Milky Way's gravitational potential and hence its dark matter halo. In the coming years, Vera Rubin, Euclid, ARRAKIHS, and NGRST...

It's paper day!!✨Very happy to announce that my first paper is (finally) on the arXiv today! Check it out if you want to find out how we can use stellar streams living in the outskirts of galaxies to learn about their dark matter halos! 🔭🧪 arxiv.org/abs/2402.13314

Can confirm Michelle is great!! Go apply!!!!

An illustration. An oval disk, which represents the Andromeda galaxy, is angled, pointing to the bottom left and top right, and takes up about one third of the view. Its core appears the brightest white and is surrounded by a thinner oval that is slightly less bright white and has a few brown lines running through it. Its edges have many small blue points representing stars. A few irregularly shaped lines representing globular cluster streams are present. A fainter blue arc is at top left. To its right is a larger, somewhat wider white line that is less than half the length of the galaxy. This straighter line has a gap, and then continues in a rough triangle. Near the bottom left of the galaxy’s blue star-filled region is another streamer that looks like an arc. It also has a gap, toward its right side. More irregular, fairly dim blue lines appear just below the right side of the galaxy. The background is black.

After the Nancy Grace Roman Space Telescope launches—by May 2027—astronomers will use its images to explore what exists between looping tendrils of stars that are pulled from globular clusters to potentially reveal dark matter in greater detail than ever before: www.stsci.edu/contents/new...