Assessing the detectability and identification of pulsar halos with H.E.S.S. and CTAO
Abstract
Pulsar halos are a class of extended gamma-ray sources, resulting from inverse Compton scattering of ambient photons by electrons and positrons believed to have escaped confinement in a pulsar wind nebula. First identified by HAWC towards PSR J0633+1746 and PSR B0656+14, a growing number of pulsar-powered gamma-ray sources is proposed as candidate halos. Using a model of isotropic diffusion, we assessed the ability of current-and-future generation imaging atmospheric Cherenkov telescopes to characterize the physical properties of such sources in the inner Galaxy. We constructed template-based pulsar halo models in the Gammapy library and fitted them to simulated H.E.S.S. and CTAO data of halos with different physical parameters. The sources were characterized spectro-morphologically using 2D Gaussian components. We assessed the statistical preference between the halo and 2D Gaussian hypotheses by the simulated data and quantified the impact of the diffuse Galactic emission. A multitude of the halos' parameters can be constrained simultaneously, including the pulsar's true age, its proper motion, the diffusion coefficient, the index of the injected particle spectrum and the injection efficiency. In some cases, the H.E.S.S. array can statistically distinguish between the halo model and a model containing 2D Gaussian components, while a significant improvement is seen with CTAO. The source's detection significance is drastically reduced with increasing intensity of the Galactic diffuse emission. If the latter is not modeled using the data-generating model, the halo parameter estimation is biased. A physically-motivated model of pulsar halos can facilitate the identification and characterization of this class of sources in high-level data analyses. The simulated halos exhibit properties that may already be found in surveys of current-generation telescopes with only a modest observation time.
Related
- Geminga and Monogem in the CTAO Era: Probing TeV Halos and Cosmic-Ray Transport
- Origin of the high-energy spectral cutoff in gamma-ray pulsar halos
- Spectral energy-loss bump and γ-ray pulsar halos
- Assessing the detectability of a realistic massive black hole binary population in LSST
- Assessing transitional pulsar candidates through a quantitative estimation of their light-curve similarity
BibTeX
@misc{sabri2026assessing,
title = {{Assessing the detectability and identification of pulsar halos with H.E.S.S. and CTAO}},
author = {Karim Sabri and Yves Gallant and Justine Devin},
howpublished = {HAL},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.36229},
eprint = {2609.36229},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05781884v1},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Assessing the detectability and identification of pulsar halos with H.E.S.S. and CTAO
AU - Karim Sabri
AU - Yves Gallant
AU - Justine Devin
PY - 2026
DA - 2026/09/28
PB - HAL
DO - 10.48550/arxiv.2609.36229
UR - https://hal.science/hal-05781884v1
AB - Pulsar halos are a class of extended gamma-ray sources, resulting from inverse Compton scattering of ambient photons by electrons and positrons believed to have escaped confinement in a pulsar wind nebula. First identified by HAWC towards PSR J0633+1746 and PSR B0656+14, a growing number of pulsar-powered gamma-ray sources is proposed as candidate halos. Using a model of isotropic diffusion, we assessed the ability of current-and-future generation imaging atmospheric Cherenkov telescopes to characterize the physical properties of such sources in the inner Galaxy. We constructed template-based pulsar halo models in the Gammapy library and fitted them to simulated H.E.S.S. and CTAO data of halos with different physical parameters. The sources were characterized spectro-morphologically using 2D Gaussian components. We assessed the statistical preference between the halo and 2D Gaussian hypotheses by the simulated data and quantified the impact of the diffuse Galactic emission. A multitude of the halos' parameters can be constrained simultaneously, including the pulsar's true age, its proper motion, the diffusion coefficient, the index of the injected particle spectrum and the injection efficiency. In some cases, the H.E.S.S. array can statistically distinguish between the halo model and a model containing 2D Gaussian components, while a significant improvement is seen with CTAO. The source's detection significance is drastically reduced with increasing intensity of the Galactic diffuse emission. If the latter is not modeled using the data-generating model, the halo parameter estimation is biased. A physically-motivated model of pulsar halos can facilitate the identification and characterization of this class of sources in high-level data analyses. The simulated halos exhibit properties that may already be found in surveys of current-generation telescopes with only a modest observation time.
ER -