Jez Castillo
@jezcastillo.bsky.social
Physics researcher at UNC Chapel Hill.
Reposted by Jez Castillo
I'm hiring 1-2 postdocs this year! If you're interested in:
GW astrophysics
(Binary) Stellar Evolution
Stellar dynamics (esp. w/ massive BHs)
Galactic dynamics (inc. stellar streams)
plz consider applying! You don't need letters initially, just a list of references.
🔭🧪
aas.org/jobregister/...
GW astrophysics
(Binary) Stellar Evolution
Stellar dynamics (esp. w/ massive BHs)
Galactic dynamics (inc. stellar streams)
plz consider applying! You don't need letters initially, just a list of references.
🔭🧪
aas.org/jobregister/...
Postdoctoral Associate Positions in Theoretical/Computational Astrophysics | American Astronomical Society
The Department of Physics and Astronomy at the University of North Carolina Chapel Hill invites applications for postdoctoral associates to conduct research in theoretical and computational astrophysi...
aas.org
September 25, 2025 at 5:33 PM
I'm hiring 1-2 postdocs this year! If you're interested in:
GW astrophysics
(Binary) Stellar Evolution
Stellar dynamics (esp. w/ massive BHs)
Galactic dynamics (inc. stellar streams)
plz consider applying! You don't need letters initially, just a list of references.
🔭🧪
aas.org/jobregister/...
GW astrophysics
(Binary) Stellar Evolution
Stellar dynamics (esp. w/ massive BHs)
Galactic dynamics (inc. stellar streams)
plz consider applying! You don't need letters initially, just a list of references.
🔭🧪
aas.org/jobregister/...
Reposted by Jez Castillo
New paper on the arXiv today about systematic errors when modelling the gravitation waveform from extreme mass ratio inspirals and their impact on LISA data science
Huge thanks to my collaborators, especially Hassan Khalvati, for getting this project over the line! 🧪⚛️🔭🧮
arxiv.org/abs/2509.08875
Huge thanks to my collaborators, especially Hassan Khalvati, for getting this project over the line! 🧪⚛️🔭🧮
arxiv.org/abs/2509.08875
September 12, 2025 at 4:47 PM
New paper on the arXiv today about systematic errors when modelling the gravitation waveform from extreme mass ratio inspirals and their impact on LISA data science
Huge thanks to my collaborators, especially Hassan Khalvati, for getting this project over the line! 🧪⚛️🔭🧮
arxiv.org/abs/2509.08875
Huge thanks to my collaborators, especially Hassan Khalvati, for getting this project over the line! 🧪⚛️🔭🧮
arxiv.org/abs/2509.08875
Reposted by Jez Castillo
I'm sad to report that Rainer (Rai) Weiss passed away yesterday at age 92. Rai developed the design for LIGO, he and Kip got it funded, trained countless researchers, and received the 2017 Nobel Prize. Rai always had time for students and treated us as equals. May his memory be a blessing
August 26, 2025 at 6:21 PM
I'm sad to report that Rainer (Rai) Weiss passed away yesterday at age 92. Rai developed the design for LIGO, he and Kip got it funded, trained countless researchers, and received the 2017 Nobel Prize. Rai always had time for students and treated us as equals. May his memory be a blessing
A decade ago I thought MattY was somewhat interesting, but his inability to shake off disputes with strangers online makes him increasingly unserious.
August 18, 2025 at 6:42 PM
A decade ago I thought MattY was somewhat interesting, but his inability to shake off disputes with strangers online makes him increasingly unserious.
Reposted by Jez Castillo
What happens when high-velocity black holes hurtle past each other in a close encounter, deflecting through spacetime but never merging? My latest paper (below) presents the first simulations of black hole scattering generated using the Spectral Einstein Code (SpEC). (1/6)
Highly accurate simulations of asymmetric black-hole scattering and cross validation of effective-one-body models
The study of unbound binary-black-hole encounters provides a gauge-invariant approach to exploring strong-field gravitational interactions in two-body systems, which can subsequently inform waveform m...
arxiv.org
July 16, 2025 at 1:45 PM
What happens when high-velocity black holes hurtle past each other in a close encounter, deflecting through spacetime but never merging? My latest paper (below) presents the first simulations of black hole scattering generated using the Spectral Einstein Code (SpEC). (1/6)
Reposted by Jez Castillo
In the time it took for me to write this we achieved what I believe to be the first ever quintuple detector lock.
June 11, 2025 at 8:52 PM
In the time it took for me to write this we achieved what I believe to be the first ever quintuple detector lock.
Reposted by Jez Castillo
I’m incredibly proud to be part of this and to have my simulations turn into the first publicly available scattering and dynamical capture waveforms!
Below is a plot I made for the Einstein Toolkit Blue Book (arXiv:2503.12263) showing the waveforms SXS:BBH:3999 (scatter) and SXS:BBH:4000 (capture).
Below is a plot I made for the Einstein Toolkit Blue Book (arXiv:2503.12263) showing the waveforms SXS:BBH:3999 (scatter) and SXS:BBH:4000 (capture).
May 21, 2025 at 5:43 AM
I’m incredibly proud to be part of this and to have my simulations turn into the first publicly available scattering and dynamical capture waveforms!
Below is a plot I made for the Einstein Toolkit Blue Book (arXiv:2503.12263) showing the waveforms SXS:BBH:3999 (scatter) and SXS:BBH:4000 (capture).
Below is a plot I made for the Einstein Toolkit Blue Book (arXiv:2503.12263) showing the waveforms SXS:BBH:3999 (scatter) and SXS:BBH:4000 (capture).
Reposted by Jez Castillo
I just registered for the #GR24Amaldi16 conference in Glasgow this July. Looking forward to seeing many of you there! Note: the early-bird deadline is on the 9th of May.
May 7, 2025 at 10:50 AM
I just registered for the #GR24Amaldi16 conference in Glasgow this July. Looking forward to seeing many of you there! Note: the early-bird deadline is on the 9th of May.
Reposted by Jez Castillo
Welcome to the #LECSTalks! series, where we showcase the people, activity, and science taking place around the LISA Early Career Scientists community. 🎤
Today we feature Ben Leather, postdoctoral researcher at the MPI for Grav Physics, talking about Waveform Modelling with Gravitational Self-Force.
Today we feature Ben Leather, postdoctoral researcher at the MPI for Grav Physics, talking about Waveform Modelling with Gravitational Self-Force.
April 10, 2025 at 12:50 PM
Welcome to the #LECSTalks! series, where we showcase the people, activity, and science taking place around the LISA Early Career Scientists community. 🎤
Today we feature Ben Leather, postdoctoral researcher at the MPI for Grav Physics, talking about Waveform Modelling with Gravitational Self-Force.
Today we feature Ben Leather, postdoctoral researcher at the MPI for Grav Physics, talking about Waveform Modelling with Gravitational Self-Force.
Reposted by Jez Castillo
Omg guys my new LIGO stickers finally arrived!
(from LolantheBySophie on Etsy - I'm afraid I bought the last two though!)
(from LolantheBySophie on Etsy - I'm afraid I bought the last two though!)
February 19, 2025 at 2:14 AM
Omg guys my new LIGO stickers finally arrived!
(from LolantheBySophie on Etsy - I'm afraid I bought the last two though!)
(from LolantheBySophie on Etsy - I'm afraid I bought the last two though!)
Reposted by Jez Castillo
A new major update to the Teukolsky package has been released (version 1.1.0). A major new feature the the ability to PN expand various Teukolsky radial functions (contribution from Jakob Neef)
February 10, 2025 at 11:09 PM
A new major update to the Teukolsky package has been released (version 1.1.0). A major new feature the the ability to PN expand various Teukolsky radial functions (contribution from Jakob Neef)
Reposted by Jez Castillo
Kasama (the only Michelin-starred Philippine cuisine in the world) makes the best breakfast sandwich I’ve ever had, bar none. Everything else was amazing except the truffle croissant which I literally spit out.
February 1, 2025 at 5:41 PM
Kasama (the only Michelin-starred Philippine cuisine in the world) makes the best breakfast sandwich I’ve ever had, bar none. Everything else was amazing except the truffle croissant which I literally spit out.
Reposted by Jez Castillo
The Supreme Court UPHOLDS the TikTok ban with no noted dissents, turning away a First Amendment challenge: www.supremecourt.gov/opinions/24p...
January 17, 2025 at 3:01 PM
The Supreme Court UPHOLDS the TikTok ban with no noted dissents, turning away a First Amendment challenge: www.supremecourt.gov/opinions/24p...
Reposted by Jez Castillo
Millennials in 2020: The youth are the FUTURE and we should listen to their profound wisdom. The youth of every generation have ALWAYS been on the side of progress! We’re still young too. Right? RIGHT?!
Millennials in 2025:
Millennials in 2025:
January 16, 2025 at 1:41 PM
Millennials in 2020: The youth are the FUTURE and we should listen to their profound wisdom. The youth of every generation have ALWAYS been on the side of progress! We’re still young too. Right? RIGHT?!
Millennials in 2025:
Millennials in 2025:
Reposted by Jez Castillo
Recent paper that cites the BHPToolkit: "Monodromy eigenvalues of the radial Teukolsky equation and their connection to the renormalized angular momentum" by Zachary Nasipak, arxiv.org/abs/2412.06503
January 10, 2025 at 2:57 PM
Recent paper that cites the BHPToolkit: "Monodromy eigenvalues of the radial Teukolsky equation and their connection to the renormalized angular momentum" by Zachary Nasipak, arxiv.org/abs/2412.06503
Saw A Complete Unknown and Nosferatu this afternoon. Watching Raiders of the Lost Ark on Blu-ray when I return home.
December 25, 2024 at 11:28 PM
Saw A Complete Unknown and Nosferatu this afternoon. Watching Raiders of the Lost Ark on Blu-ray when I return home.
Reposted by Jez Castillo
Radioactive decay is difficult to envision unless you have a cloud chamber. Here I use a piece of naturally radioactive monazite crystal (~25 cm) to produce very energetic alpha particles - a decay product - that ionize alcohol-saturated vapor. I use this in Geochron and Natural Disasters classes.
December 8, 2024 at 1:46 PM
Radioactive decay is difficult to envision unless you have a cloud chamber. Here I use a piece of naturally radioactive monazite crystal (~25 cm) to produce very energetic alpha particles - a decay product - that ionize alcohol-saturated vapor. I use this in Geochron and Natural Disasters classes.
Reposted by Jez Castillo
New paper the cites the BHPToolkit: "Analytic solution for the motion of spinning particles in Kerr space-time" by Viktor Skoupý, Vojtěch Witzany, arxiv.org/abs/2411.16855
November 27, 2024 at 10:51 AM
New paper the cites the BHPToolkit: "Analytic solution for the motion of spinning particles in Kerr space-time" by Viktor Skoupý, Vojtěch Witzany, arxiv.org/abs/2411.16855
Reposted by Jez Castillo
New paper the cites the BHPToolkit: "Gravitational self-force with hyperboloidal slicing and spectral methods" by Benjamin Leather, arxiv.org/abs/2411.14976
November 25, 2024 at 9:43 AM
New paper the cites the BHPToolkit: "Gravitational self-force with hyperboloidal slicing and spectral methods" by Benjamin Leather, arxiv.org/abs/2411.14976
Reposted by Jez Castillo
Paper day! My article on counterintuitive properties of accelerated motion is out in Am. J. Phys. (It's Open Access, and also an "Editor's pick," yay!) 🧪⚛️🎢 - things like "two objects that keep a constant distance from each other can still be in non-zero relative motion!"
Counterintuitive properties of relativistic relative motion for accelerated observers
Editor's Note: Could a laser rangefinder give constant readings even though the distance between two objects is changing? Will two observers always agree about
pubs.aip.org
November 21, 2024 at 1:44 PM
Paper day! My article on counterintuitive properties of accelerated motion is out in Am. J. Phys. (It's Open Access, and also an "Editor's pick," yay!) 🧪⚛️🎢 - things like "two objects that keep a constant distance from each other can still be in non-zero relative motion!"
Reposted by Jez Castillo
New paper today that cites the BHPToolkit: "Post-Newtonian expansion of energy and angular momentum fluxes: inclined spherical orbits about a Kerr black hole" by Jezreel C. Castillo, Charles R. Evans, Chris Kavanagh, Jakob Neef, Adrian Ottewill, Barry Wardell, arxiv.org/abs/2411.09700
November 15, 2024 at 10:46 AM
New paper today that cites the BHPToolkit: "Post-Newtonian expansion of energy and angular momentum fluxes: inclined spherical orbits about a Kerr black hole" by Jezreel C. Castillo, Charles R. Evans, Chris Kavanagh, Jakob Neef, Adrian Ottewill, Barry Wardell, arxiv.org/abs/2411.09700