The Next Generation BLAST Experiment

Abstract

The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) was a suborbital experiment designed to map magnetic fields in order to study their role in star formation processes. BLASTPol made detailed polarization maps of a number of molecular clouds during its successful flights from Antarctica in 2010 and 2012. We present the next-generation BLASTPol instrument (BLAST-TNG) that will build off the success of the previous experiment and continue its role as a unique instrument and a test bed for new technologies. With a 16-fold increase in mapping speed, BLAST-TNG will make larger and deeper maps. Major improvements include a 2.5 m carbon fiber mirror that is 40% wider than the BLASTPol mirror and ~3000 polarization sensitive detectors. BLAST-TNG will observe in three bands at 250, 350, and 500 microns. The telescope will serve as a pathfinder project for microwave kinetic inductance detector (MKID) technology, as applied to feedhorn coupled submillimeter detector arrays. The liquid helium cooled cryostat will have a 28-day hold time and will utilize a closed-cycle $^3$He refrigerator to cool the detector arrays to 270 mK. This will enable a detailed mapping of more targets with higher polarization resolution than any other submillimeter experiment to date. BLAST-TNG will also be the first balloon-borne telescope to offer shared risk observing time to the community. This paper outlines the motivation for the project and the instrumental design

Understanding the Origin of the Magnetic Field Morphology in the Wide-binary Protostellar System BHR 71

“…Upcoming surveys of large numbers of young, embedded sources will soon reveal how common is each of the scenarios that individual-source studies have recently unveiled: natal hourglass-shaped fields, magnetic fields affected by bipolar outflows, and possible magnetized accretion streamers. Furthermore, observations of large-scale magnetic fields using current and upcoming single-dish polarimeters on instruments such as the Stratospheric Observatory for Infrared Astronomy (SOFIA; Vaillancourt et al 2007), the James-Clerk-Maxell Telescope (JCMT; e.g., the BISTRO survey: Ward- Thompson et al 2017); the BLAST-TNG balloon-borne experiment (Galitzki et al 2014), the IRAM 30 m telescope (Ritacco et al 2017), and the Large Millimeter Telescope (LMT) will allow us to understand how the larger-scale magnetic environment connects with the myriad small-scale magnetic field morphologies revealed by ALMA.…”

Cryogenic LED pixel-to-frequency mapper for kinetic inductance detector arrays

“…For example, we are developing feed-horn coupled dual-polarization sensitive MKID [11] arrays made from titanium-nitride/titanium (TiN/Ti) multilayer films with target T c ≈ 1.4 K for the BLAST-TNG experiment [12]. We have made a 90 pixel hexagonal close-packed TiN MKID array on a 76.2 mm intrinsic Si wafer to study the wafer uniformity ( Fig.…”

Photon-noise limited sensitivity in titanium nitride kinetic inductance detectors

“…These polarization-sensitive detectors are under development for the next-generation BLAST experiment. 19 The 1.4 K transition temperature of the film is chosen to accommodate operation from a 300 mK bath temperature, as is planned for BLAST. The devices are feedhorn-coupled to a variable temperature blackbody source.…”

“…The design and measured polarization performance of this detector type is the subject of a future publication. For polarimetry applications, such as BLAST, 19 g c ) g x is required. By splitting the absorber width into 2 lm strips, simulations suggest that g c $ 0.8 and g x Շ 0.02 are achievable.…”