Abstract
We demonstrate that the integrated gravitational wave signal of Type Ia
supernovae (SNe Ia) in the single-degenerate channel out to cosmological
distances gives rise to a continuous background to spaceborne gravitational
wave detectors, including the Big Bang Observer (BBO) and Deci-Hertz
Interferometer Gravitational wave Observatory (DECIGO) planned missions. This
gravitational wave background from SNe Ia acts as a noise background in the
frequency range 0.1 - 10 Hz, which heretofore was thought to be relatively free
from astrophysical sources apart from neutron star binaries, and therefore a
key window in which to study primordial gravitational waves generated by
inflation. While inflationary energy scales of $\gtrsim 10^{16}$ GeV yield
inflationary gravitational wave backgrounds in excess of our range of predicted
backgrounds, for lower energy scales of $\sim10^{15}$ GeV, the inflationary
gravitational wave background becomes comparable to the noise background from
SNe Ia.