Kasper Elm Heintz
@KosmosKasper
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Assistant Professor @DAWNcopenhagen / @uni_copenhagen — observer of GRBs, FRBs and GW counterparts — Instrument scientist for @NotTransient
Joined June 2019
Congrats to @lucie_rowland1, @Introspect_Rych, and @TheREBELSTeam for this exciting discovery and magnificent observations!
#BreakingNews Space oddity: Most distant Milky-Way-like galaxy yet observed. 🌀Dubbed REBELS-25, this disc galaxy seems as orderly as present-day galaxies, but we see it as it was when the Universe was only 700 million years old 🔗 https://t.co/xid0FPXNoj
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Cool new JWST survey I had the honor of being part of, heroically led by @jorryt_m and @Rohan_Naidu , now on ArXiv 🔥 Lots of exciting new results, proposals, etc. to come 🤩
Today on the arXiv: All the Little Things in the Abell 2744 field: ~1600 redshifts measured with our Cycle 2 NIRCam grism program, and much, much more, showcasing the discovery space of this instrument Among these 1600: 1) An analog of the Milky Way + local group 12.7 Gyr ago
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Are you an ECR? Do you like #JWST ? High-z galaxies/SMBHs? Skiing/curling/ice-skating in the Swiss Alps? Applications are now open for the 54th Saas-Fee Course on "Galaxies and Black Holes in the 1 Gyr as seen with the JWST" - Jan 27-31, 2025 - more info: https://t.co/NqH5vQ3KR5
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I am organizing an Astro-workshop, with a major goal to foster new networks and collaborations — For this, we are planning a “network bingo” where people have to find/talk to someone who… Any good ideas? 😅 Currently includes: has observed at the VLT, work on sims, etc.. Thx🙏
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Super proud to share that my brilliant *Bachelor* student Chamilla Terp has just had her first, first-author paper accepted for publication in A&A 🤩 this was based on her thesis work of the peculiar galaxy at z=5.94 observed by @JADES_astro w. JWST: https://t.co/MSmS5WhDBf
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ALMA reviews are in — 4/4 rejections 🥲 amazlingly there were ranked one in each quartile…
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@JADES_astro @DAWNCopenhagen We are thus observing this galaxy proto-cluster in its infancy, still mostly dominated by cold, neutral gas, slowly evolving into one of the most massive structures in the Universe during the next ~13 billion years.
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@JADES_astro @DAWNCopenhagen A further confirmation of these findings from simulations were from Doug Rennehan’s work https://t.co/KAE3oADN1D showing large covering fractions of HI gas with abundant column densities, when specifically targeting massive galaxy overdensities.
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@JADES_astro @DAWNCopenhagen This was mostly based on simulations by Jake Bennett and Debora Sijacki: https://t.co/qLtQI5KtXG showing beautiful large-scale, cold neutral gas structures
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@JADES_astro @DAWNCopenhagen This result greatly challenges typical reionization simulations showing extended ionizing regions around early galaxy overdensities — focusing on detailed galaxy formation simulations, however, revealed similar extreme HI columns and covering fractions!
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@JADES_astro To investigate whether the galaxy sightlines probed the same structure, a brilliant PhD student Albert Sneppen here @DAWNCopenhagen, looked at the clustering of the HI columns, finding it very unlikely that two nearby sightlines (projected) showed similar abundances uncorrelated
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The galaxy overdensity was first discovered by Helton and collaborators from @JADES_astro at z~5.4, revealing a massive structure that likely evolves into a Coma-like cluster by z=0.
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This means that we could now use several galaxies as backlights to chart the scales and distribution of the cold, neutral gas permeating this galaxy overdensity.
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This cold, neutral gas was detected based on extremely strong DLAs in several background galaxy spectra to the cluster. At first, we found it weird that we couldn’t get the now standard high-z DLA proxy to work for each. But that’s because the DLAs are from gas in the cluster!
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Paper day 🥳 today on @arxiv, we present the detection of a *massive* neutral gas reservoir in and around a galaxy proto-cluster at z=5.4, when the Universe was just 1 billion years old. See more here👇and the 🧵 below: https://t.co/0hgVnfsSt3
arxiv.org
Galaxy clusters are the most massive, gravitationally-bound structures in the Universe, emerging through hierarchical structure formation of large-scale dark matter and baryon overdensities. Early...
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Jeg fik James Webb-teleskopet i hovedet da jeg optog denne video! Se samtalen med @KosmosKasper på @YouTube her: https://t.co/PDbNuKKkLV
#astronomi #dkastro #dkviden #dkforck
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For the Danish-speaking crowd: I had the pleasure of chatting with @astronerd for this weeks episode on @YouTube about some of my recent research 🌌 Check it out 👇 https://t.co/VN1Gvnx14J
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@KosmosKasper et al. use #JWST to identify abundant neutral gas in three #galaxies at redshifts 9 to 11, shortly after the Big Bang. They find enough gas to supply the galaxies' rapid star formation, but only for a short period. https://t.co/RnmKE1znJ8
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@DAWNCopenhagen @Carlsbergfondet @GrundforskFond More on this exciting discovery later, but in short: We are now seeing galaxy formation *in progress*, with @NASAWebb / @ESA_Webb once again pushing the frontier of what we can learn about the early Universe 💫
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This work was done in collaboration with several researchers at @DAWNCopenhagen, also including some key international collaborators, and would not have been possible without the vision and support from @Carlsbergfondet and @GrundforskFond
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