Light Echoes from X-ray Transients as Probes of Interstellar Dust and Galactic Structure
Abstract
When an X-ray Transient exhibits a bright flare, scattering by interstellar dust clouds can give rise to a light echo in the form of concentric rings. Several such echoes have been detected, leading to significant discoveries and press attention. We propose a Target-of-Opportunity campaign to observe a cycle 23 echo with the aim of following the temporal evolution of the echo in order to (a) map the 3D distribution of interstellar dust along the line of sight to parsec accuracy, (b) constrain the composition and grain size distribution of ISM dust in each of the clouds towards the source, (c) measure the distance to the X-ray source, (d) constrain the velocity dispersion of molecular clouds, and (e) search for evidence of streaming velocities by combining X-ray and CO data.
- Publication:
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Chandra Proposal
- Pub Date:
- September 2022
- Bibcode:
- 2022cxo..prop.6342H
- Keywords:
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- Chandra Proposal ID #24910103