Some of you may know that I did a PhD in Physics, specifically studying black holes 🕳️. While I'm no longer an active researcher in the field, I still try to keep tabs on the latest work published by my former colleagues. This week, I found two papers that really caught my interest.
📝 The first paper, led by Dr. Jonathan Cohn at Dartmouth, explores why some galaxies in the early universe appear to host "overmassive" black holes—those that sit well above the typical scaling relations between black hole mass and host galaxy properties. Using cosmological simulations, the team shows that a galaxy's growth history plays a critical role: galaxies that form rapidly and then quench early tend to evolve into compact "red nuggets" with massive central black holes. These galaxies remain compact over cosmic time, leading to their present-day "outlier" status on scaling relations. Rather than being anomalies, they may be relics of a very different evolutionary path.
🌌 The second paper, led by PhD Candidate Jacob Pilawa at UC Berkeley, presents a new triaxial stellar dynamical measurement of the black hole in NGC 315—a massive elliptical galaxy and a strong radio emitter. Using over 2300 stellar kinematic constraints and a sophisticated orbit modeling approach, they estimate the black hole mass to be 3 billion solar masses. This is notably higher than the mass inferred from earlier CO gas kinematics, but still within expected scatter. With a predicted shadow size of ~4.7 microarcseconds and high millimeter flux, NGC 315 is now a top candidate for future black hole imaging missions at horizon-scale resolution.
Together, these papers offer exciting insights into both the cosmic origins and present-day measurements of the largest black holes in the universe. It's great to see this kind of progress—and makes me miss the field just a little bit 😉 . 🚀🔭
Kyle Kabasares
Some of you may know that I did a PhD in Physics, specifically studying black holes 🕳️. While I'm no longer an active researcher in the field, I still try to keep tabs on the latest work published by my former colleagues. This week, I found two papers that really caught my interest.
📝 The first paper, led by Dr. Jonathan Cohn at Dartmouth, explores why some galaxies in the early universe appear to host "overmassive" black holes—those that sit well above the typical scaling relations between black hole mass and host galaxy properties. Using cosmological simulations, the team shows that a galaxy's growth history plays a critical role: galaxies that form rapidly and then quench early tend to evolve into compact "red nuggets" with massive central black holes. These galaxies remain compact over cosmic time, leading to their present-day "outlier" status on scaling relations. Rather than being anomalies, they may be relics of a very different evolutionary path.
🌌 The second paper, led by PhD Candidate Jacob Pilawa at UC Berkeley, presents a new triaxial stellar dynamical measurement of the black hole in NGC 315—a massive elliptical galaxy and a strong radio emitter. Using over 2300 stellar kinematic constraints and a sophisticated orbit modeling approach, they estimate the black hole mass to be 3 billion solar masses. This is notably higher than the mass inferred from earlier CO gas kinematics, but still within expected scatter. With a predicted shadow size of ~4.7 microarcseconds and high millimeter flux, NGC 315 is now a top candidate for future black hole imaging missions at horizon-scale resolution.
Together, these papers offer exciting insights into both the cosmic origins and present-day measurements of the largest black holes in the universe. It's great to see this kind of progress—and makes me miss the field just a little bit 😉 . 🚀🔭
Paper 1: arxiv.org/abs/2504.00172
Paper 2: arxiv.org/abs/2504.01071
8 months ago (edited) | [YT] | 50