Aspera: the UV SmallSat telescope to detect and map the warm-hot gas phase in nearby galaxy halos
Haeun Chung, Carlos J. Vargas, Erika Hamden, Thomas J. McMahon, Kerry Gonzales, Aafaque R. Khan, Simran Agarwal, Hop Bailey, Peter Behroozi, Trenton Brendel, Heejoo Choi, Tom Connors, Lauren Corlies, Jason Corliss, R.‐J. Dettmar, David Dolana, Ewan S. Douglas, John Guzman, D. Hamara, W. M. Harris, K. Harshman, C. W. Hergenrother, Keri Hoadley, John Kidd, Daewook Kim, Jessica Li, Manny Montoya, Corwynn Sauve, David Schiminovich, Sanford Selznick, Oswald H. W. Siegmund, M. Ward, Ellie Wolcott, Dennis Zaritsky
Abstract
Aspera is an extreme-UV (EUV) Astrophysics small satellite telescope designed to map the warm-hot phase coronal gas around nearby galaxy halos. Theory suggests that this gas is a significant fraction of a galaxy’s halo mass and plays a critical role in its evolution, but its exact role is poorly understood. Aspera observes this warm-hot phase gas via Ovi emission at 1032 °A using four parallel Rowland-Circle-like spectrograph channels in a single payload. Aspera’s robust-and-simple design is inspired by the FUSE spectrograph, but with smaller, four 6.2 cm × 3.7 cm, off-axis parabolic primary mirrors. Aspera is expected to achieve a sensitivity of 4.3×10<sup>−19</sup> erg/s/cm<sup>2</sup>/arcsec<sup>2</sup> for diffuse Ovi line emission. This superb sensitivity is enabled by technological advancements over the last decade in UV coatings, gratings, and detectors. Here we present the overall payload design of the Aspera telescope and its expected performance. Aspera is funded by the inaugural 2020 NASA Astrophysics Pioneers program, with a projected launch in late 2024.