James Webb Space Telescope Feed Post

Faint light of old neutron stars and detectability at the James Webb Space Telescope Published: 5/10/2022 8:02:45 PM Updated: 7/13/2023 5:16:15 PM

Paper abstract: Isolated ideal neutron stars (NS) of age >10^9 yrs exhaust thermal androtational energies and cool down to temperatures below \mathcal{O}(100) K.Accretion of particle dark matter (DM) by such NS can heat them up throughkinetic and annihilation processes. This increases the NS surface temperatureto a maximum of ~ 2550 K in the best case scenario. The maximum accretionrate depends on the DM ambient density and velocity dispersion, and on the NSequation of state and their velocity distributions. Upon scanning over thesevariables, we find that the effective surface temperature varies at most by~ 40\%. Black body spectrum of such warm NS peak at near infraredwavelengths with magnitudes in the range potentially detectable by the JamesWebb Space Telescope (JWST). Using the JWST exposure time calculator, wedemonstrate that NS with surface temperatures \gtrsim 2400 K, located at adistance of 10\,pc can be detected through the F150W2 (F322W2) filters of theNIRCAM instrument at SNR\,\gtrsim 10 (5) within 24 hours of exposure time.Independently of DM, an observation of NS with surface temperatures \gtrsim2500 K will be a formative step towards testing the minimal cooling paradigmduring late evolutionary stages.