MRI: Development of a Wide-Field Infrared Camera for Robotic Surveys of the Dynamic Astronomical Sky

Massachusetts Institute Of Technology, Cambridge MA

Investigators

Abstract

The US astronomical community has embarked on a systematic effort to monitor the dynamic sky, leveraging advances in robotic telescope operation, remote-imaging sensors, large-scale computing and machine learning to find, classify, and unveil transient cosmic sources. Numerous surveys already operate at visible wavelengths, but the high cost of conventional sensors has discouraged similar efforts in the infrared (IR), despite strong scientific motivation. Advances in material growth driven by the defense and surveillance markets have yielded lower-cost IR sensors of the semiconductor InGaAs, with sufficiently low noise to detect faint astronomical sources. The Wide-field Infrared Transient Explorer (WINTER) will mosaic six High Definition format InGaAs detectors to produce the world's widest-area IR camera and conduct a deep robotic survey of the dynamic infrared sky. In addition to its primary science mission, studying how the heaviest elements of the periodic table are synthesized in colliding neutron stars identified via gravitational waves, WINTER will devote observing time to support undergraduate research and laboratory education at the intersection of Big Data and the physical sciences. WINTER is an infrared camera with a 1.2 x 1.0 degree field of view that will be installed on a dedicated 1-meter robotic telescope at Palomar Observatory. A simple prototype shows that thermo-electrically cooled InGaAs behind an ambient temperature optical train yields broadband images (at 0.9-1.7 microns) limited by shot noise from the sky, rather than sensor noise. This removes the requirement for cryogenic optics and vacuum cryostats, greatly reducing system cost and complexity relative to traditional IR imagers with HgCdTe sensors. During each year of a 5-year baseline survey, WINTER will monitor the entire Northern sky to a depth of J=19.2 (single visit), or J=20 (combined), and release calibrated images and transient alerts to the public. WINTER is sensitive to emission from the r-process enhanced ejecta of kilonovae over the full horizon of Advanced LIGO, and will autonomously interrupt its sky survey to search for the isotropic infrared counterparts of gravitational-wave events. WINTER's IR capability is uniquely sensitive to emission from both binary neutron star mergers and neutron star-black hole mergers independent of viewing angle, opacity, mass ratio and remnant lifetime. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.