2014ApJ...790...52M

Deep X-ray observations of the post-explosion environment around the very nearby Type Ia SN 2014J (d_L= 3.5 Mpc) reveal no X-ray emission down to a luminosity L_x< 7x10³⁶ erg/s (0.3-10 keV) at δt ∼ 20 days after the explosion. We interpret this limit in the context of inverse Compton emission from upscattered optical photons by the supernova shock and constrain the pre-explosion mass-loss rate of the stellar progenitor system to be {dot}M < 10^–9 M_☉/yr (for wind velocity v_w= 100 km/s). Alternatively, the SN shock might be expanding into a uniform medium with density n_CSM< 3/cm3. These results rule out single-degenerate (SD) systems with steady mass loss until the terminal explosion and constrain the fraction of transferred material lost at the outer Lagrangian point to be ≤ 1%. The allowed progenitors are (1) white dwarf-white dwarf progenitors, (2) SD systems with unstable hydrogen burning experiencing recurrent nova eruptions with recurrence time t < 300 yr, and (3) stars where the mass loss ceases before the explosion.