AstroNote 2026-196

The Chandra X-ray observatory conducted an 18.4 ks observation in response to a Director’s Discretionary Time proposal (PI: Jacobson-Galán) at the position of SN2026obc, classified as a Type Icn supernova (Wise et al.; AstroNote 2026-180), beginning at UTC 2026-06-15 04:56:27 (~15 days since first ZTF detection). 

We used the ACIS-S detector in its imaging mode. We use ciao to calculate an upper limit on the unabsorbed flux at this location and found a limit of <3.6e-15 erg/s/cm^2 assuming a Gamma=2 power law spectral model. At a distance of 85 Mpc, this corresponds to a limit on the X-ray luminosity of <3.1e39 erg/s. This CXO observation represents the deepest X-ray limit on a type Icn SN to date and could indicate significant soft X-ray absorption from on-going CSM interaction. X-ray light curves of type Ibn SNe are known to rise at later epochs (>20-30 days post-explosion) and therefore further multi-wavelength monitoring is encouraged. 

We would like to thank Pat Slane, Jack Steiner, and the Chandra X-ray Center for rapidly approving and executing these observations.