gamma hosts from the past: reheating neutron stars with supernova-sourced ALPs

Introduction to the show: ident: Astrophysics Radio. Generated commentary on the latest astrophysics papers.

Vera: We're looking at the paper: "gamma hosts from the past".

Jocelyn: Here's the gist of the paper. This letter shows that an analogous mechanism with a → γγ decays could overheat NSs above luminosities expected from their passive cooling, using which we obtain for the first time constraints reaching previously unprobed ALP parameters.

Vera: How it works Axion-like particles (ALPs) can be copiously produced in the hot and dense environment of a core-collapse supernova (SN) if their mass is within an order of magnitude of the supernova temperature, allowing them to remain gravitationally bound to the neutron star remnant and decay to photons over its lifetime, thereby reheating it If their mass is within an order of magnitude of the supernova temperature, a non-negligible fraction of them will remain gravitationally bound to the neutron star remnant and can then decay to photons over the lifetime of the neutron star, thereby reheating it.

Jocelyn: ALP Production at Core-Collapse Supernovae The primary production channel for ALPs in core-collapse supernovae is nucleon-nucleon bremsstrahlung (NN → N N a).

Vera: This process occurs when the core of the PNS has a temperature of O(10) MeV, setting the maximum mass scale for ALPs produced by this channel.

Title and authors: Title: Detection of Solar-like Oscillations and Granulation at Infrared Wavelengths using JWST

Authors: Angharad Weeks, Daniel Huber, Timothy R. Bedding, Jared Splinter, Hans Kjeldsen, Yaguang Li, Courtney Crawford, Daniel Hey, David Lafreniere.

Vera: This paper is titled "Detection of Solar-like Oscillations and Granulation at Infrared Wavelengths using JWST." It’s about using the James Webb Space Telescope to look for solar-like oscillations and granulation on a star called WASP-one hundred twenty-one.

Jocelyn: Right, so it focuses on that specific star, WASP-one hundred twenty-one and what kind of light we can detect at infrared wavelengths that reveals its internal structure.

Subrahmanyan: The authors are a large group of researchers working on stellar astrophysics and modeling the atmosphere of stars. They are connecting observational data with theoretical models for how stars behave.

Vera: And the key finding is that they detected these oscillations and granulation, but they found that the amplitudes of both things decrease with wavelength, which is consistent with what we expect >

Jocelyn: But there's a twist; their functional form for this decrease deviates from simple blackbody scaling. That implies something about how the energy is being transported in that star's atmosphere >

Subrahmanyan: The paper uses time-series data from JWST observations of WASP-one hundred twenty-one to model these things, which is a pretty complex way to get the results >

Vera: They used thirty-six point nine hours of NIRISS/SOSS observations, which was part of the NIRISS Exploration of the Atmospheric diversity of Transiting exoplanets Guaranteed Time Observations Programme GTO one thousand two hundred one >

The paper's summary: Vera: So, in "gamma hosts from the past: reheating neutron stars with supernova-sourced ALPs," they show how these particles can cause a neutron star to heat up after a supernova, and they use current data to put limits on how much heating we should expect.

Jocelyn: They found that if these ALPs are gravitationally bound, they decay into photons and reheat the star, which is a way to get energy back into the star after the supernova explosion has passed its peak heat >

Subrahmanyan: This connects the microscopic physics of particle decay to the macroscopic behavior of neutron stars in the universe. It shows how a process from inside a supernova can affect something that's settled down for centuries.

Vera: Exactly, it’s about these hidden particles interacting with matter in extreme environments, which is something we can’t easily see elsewhere >

Jocelyn: And it changes how we think about what kind of signals we should be looking for when we eventually find a neutron star or use infrared telescopes to observe them >

Subrahmanyan: If these limits hold up, it helps us narrow down the parameter space for models involving axions or other light scalar fields that might exist in our universe >

The paper's improvements: Vera: So, they’re looking at how this research suggests ways to make these results even more useful for searching for new physics. They suggest using AI to model ALP production rates from things like nucleon-nucleon bremsstrahlung and pion conversion channels with much higher precision.

Jocelyn: Right, it’s not just about finding a signal, but about actually improving how we search for those exotic particles in the future by training an AI to constrain the ALP-photon coupling constant, that g gamma gamma value >

Subrahmanyan: That specific parameter space constraint is really helpful for the next generation of experiments because it tells us exactly what to look for when we use telescopes like JWST or even future infrared instruments >

Vera: That means we get a much tighter window on where these particles might live in terms of mass and how strongly they interact with photons >

Jocelyn: And the paper suggests that by using these advanced AI tools, we can project sensitivity limits onto those telescopes themselves, telling them where they should focus their search efforts >

Subrahmanyan: So, in the bigger picture, this is about turning a theoretical concept—these hidden sectors—into something we can actually test with observational data from astrophysics >

Vera: It’s about using our existing and future instruments to probe physics that doesn't happen in our daily life >

Jocelyn: And it really pushes the envelope on how we use the sky to find evidence for things like axions or sterile neutrinos >

Conclusion: Vera: So we’re wrapping up this look at "gamma hosts from the past: reheating neutron stars with supernova-sourced ALPs." Basically, they show that these ALPs can cause a neutron star to heat up after a supernova, and they’re using current data to put limits on how much heating we should expect >

Jocelyn: They found that if these ALPs are gravitationally bound, they decay into photons and reheat the star, which is a way to get energy back into the star after the supernova explosion has passed its peak heat >

Subrahmanyan: It really connects the microscopic physics of particle decay to the macroscopic behavior of neutron stars in the universe >

Vera: The implication is that these hidden particles are interacting with matter in extreme environments, which is something we can’t easily see elsewhere >

Jocelyn: And it changes how we think about what kind of signals we should be looking for when we eventually find a neutron star or use infrared telescopes to observe them >

Subrahmanyan: If these limits hold up, it helps us narrow down the parameter space for models involving axions or other light scalar fields that might exist in our universe >