S. Chatterjee, R. Garani, R. K. Jain, B. Kanodia, M. S. N. Kumar, S. K. Vempati
Abstract
Isolated ideal neutron stars (NS) of age >109 yr exhaust thermal and rotational energies and cool down to temperatures below O(100 ) K . Accretion of particle dark matter (DM) by such NS can heat them up through kinetic and annihilation processes. This increases the NS surface temperature to a maximum of ∼2550 K in the best case scenario. The maximum accretion rate depends on the DM ambient density and velocity dispersion, and on the NS equation of state and their velocity distributions. Upon scanning over these variables, we find that the effective surface temperature varies at most by ∼40 %. Black-body spectrum of such warm NS peak at near infrared wavelengths with magnitudes in the range potentially detectable by the James Webb Space Telescope (JWST). Using the JWST exposure time calculator, we demonstrate that NS with surface temperatures ≳2400 K , located at a distance of 10 pc can be detected through the F150W2 (F322W2) filters of the NIRCAM instrument at SNR ≳10 (5) within 24 hours of exposure time. Independently of DM, an observation of NS with surface temperatures ≳2500 K will be a formative step toward testing the minimal cooling paradigm during late evolutionary stages.
Keywords
Astrophysics - High Energy Astrophysical Phenomena; Astrophysics - Cosmology and Nongalactic Astrophysics; High Energy Physics - Phenomenology
Physical Review D
Volume 108, Issue 2, Page L021301
2023 July
