2014MNRAS.442.3400N

We analysed archival data of Chandra pre-explosion observations of the position of SN 2014J in M82. No X-ray source at this position was detected in the data, and we calculated upper limits on the luminosities of the progenitor. These upper limits allow us to firmly rule out an unobscured supersoft X-ray source progenitor with a photospheric radius comparable to the radius of white dwarf near the Chandrasekhar mass ( ∼ 1.38 M_☉) and mass accretion rate in the interval where stable nuclear burning can occur. However, due to a relatively large hydrogen column density implied by optical observations of the supernova, we cannot exclude a supersoft source with lower temperatures, kT ≲ 70 eV. We find that the supernova is located in the centre of a large structure of soft diffuse emission, about 200 pc across. The mass, ∼ 3x10⁴ M_☉ and short cooling time of the gas, τcool ∼ 8 Myr, suggest that it is a supernova-inflated superbubble, associated with the region of recent star formation. If SN 2014J is indeed located inside the bubble, it likely belongs to the prompt population of Type Ia supernovae, with a delay time as short as ∼ 50 Myr. Finally, we analysed the one existing post-supernova Chandra observation and placed upper limit of ∼ (1-2)x10³⁷ erg/s on the X-ray luminosity of the supernova itself.