"While it may sound a bit odd, we actually learned a great deal about this supernova by detecting absolutely nothing" states team leader Margutti at Harvard Astrophysics.
That's too damn clean to be a merger of two white dwarf stars. A merger of two stars would produce enormous amounts of x-rays, gamma rays, gaseous material filled turbulence, and obviously core remnants. All this is lacking in every case for type Ia supernovas, proving that they are not standard candles capable of measuring the expansion by dark energy.
Stringent constraints established by the team on the environment, rather than on their mechanism, actually refutes type Ia supernova models.