Near-field Cosmologist and Assistant Professor of Astronomy and Astrophysics at University of Chicago. he/himhttps://bsky.app/profile/alexji.bsky.socialhttps://bsky.app/profile/alexji.bsky.social/post/3mkx3zhgi3s2cAn ominous slug looms over its prey [contains quote post or other embedded content]03 May 2026 11:55 +0000at://did:plc:65hgl6ql7asnjs6lrquyloi2/app.bsky.feed.post/3mkx3zhgi3s2chttps://bsky.app/profile/alexji.bsky.social/post/3mioorcqosc2iMooooooon (ok mostly Earth so far) [contains quote post or other embedded content]04 Apr 2026 16:46 +0000at://did:plc:65hgl6ql7asnjs6lrquyloi2/app.bsky.feed.post/3mioorcqosc2ihttps://bsky.app/profile/alexji.bsky.social/post/3mimhz2lu622v🔭 Paper day, and it’s a big one! We have found the most metal-poor object known in the universe. It’s a star, and it comes to us from our nearby friend the Large Magellanic Cloud. Out in Nature Astronomy today: rdcu.be/fbylI https://rdcu.be/fbylI03 Apr 2026 19:40 +0000at://did:plc:65hgl6ql7asnjs6lrquyloi2/app.bsky.feed.post/3mimhz2lu622vhttps://bsky.app/profile/alexji.bsky.social/post/3mifhno2etc2aSADLY my April Fool’s paper on this topic has been desk rejected by arxiv moderators!! [contains quote post or other embedded content]01 Apr 2026 00:45 +0000at://did:plc:65hgl6ql7asnjs6lrquyloi2/app.bsky.feed.post/3mifhno2etc2ahttps://bsky.app/profile/alexji.bsky.social/post/3mhv3is463k2aIt’s truly insane that an object with metallicity upper limit <2% solar is being claimed as containing Pop III stars25 Mar 2026 12:25 +0000at://did:plc:65hgl6ql7asnjs6lrquyloi2/app.bsky.feed.post/3mhv3is463k2ahttps://bsky.app/profile/alexji.bsky.social/post/3mh6yn5pjps2n🔭 Paper day! Ani Chiti + MAGIC discovery the first highly carbon-enhanced star in an ultra-faint dwarf galaxy. We suggest most CEMP stars form in such places. News article: https://news.uchicago.edu/story/ancient-star-opens-window-early-days-universe Paper: https://www.nature.com/articles/s41550-026-02802-z Arxiv version (updated soon): arxiv.org/abs/2508.0405316 Mar 2026 17:35 +0000at://did:plc:65hgl6ql7asnjs6lrquyloi2/app.bsky.feed.post/3mh6yn5pjps2nhttps://bsky.app/profile/alexji.bsky.social/post/3mgukuw6gnc27🔭 Storytime! This paper consumed my soul for a month and it turns out that you have to look at your 2D spectroscopic data. Thread... https://ui.adsabs.harvard.edu/abs/2024OJAp....7E..66T/abstract [contains quote post or other embedded content]12 Mar 2026 14:02 +0000at://did:plc:65hgl6ql7asnjs6lrquyloi2/app.bsky.feed.post/3mgukuw6gnc27https://bsky.app/profile/alexji.bsky.social/post/3mezsb5k3gc23🔥🐎 here we come!17 Feb 2026 05:08 +0000at://did:plc:65hgl6ql7asnjs6lrquyloi2/app.bsky.feed.post/3mezsb5k3gc23https://bsky.app/profile/alexji.bsky.social/post/3mcubuu4mpc2tFirst* stars** *many generations after Pop III **star clusters [contains quote post or other embedded content]20 Jan 2026 13:41 +0000at://did:plc:65hgl6ql7asnjs6lrquyloi2/app.bsky.feed.post/3mcubuu4mpc2thttps://bsky.app/profile/alexji.bsky.social/post/3mbwbx5rlls2iGotta find those PISNe [contains quote post or other embedded content]08 Jan 2026 15:22 +0000at://did:plc:65hgl6ql7asnjs6lrquyloi2/app.bsky.feed.post/3mbwbx5rlls2ihttps://bsky.app/profile/alexji.bsky.social/post/3mbw5g4pobs2iGood lord it has only been a week of 202608 Jan 2026 14:01 +0000at://did:plc:65hgl6ql7asnjs6lrquyloi2/app.bsky.feed.post/3mbw5g4pobs2ihttps://bsky.app/profile/alexji.bsky.social/post/3mbsoklon6c2dRocks are not a given!! [contains quote post or other embedded content]07 Jan 2026 04:57 +0000at://did:plc:65hgl6ql7asnjs6lrquyloi2/app.bsky.feed.post/3mbsoklon6c2dhttps://bsky.app/profile/alexji.bsky.social/post/3mbovz32nxc23Slack really does not need to wish me happy new year especially once in every workspace good lord05 Jan 2026 17:00 +0000at://did:plc:65hgl6ql7asnjs6lrquyloi2/app.bsky.feed.post/3mbovz32nxc23