BLASTPol

BLASTPol
Name	BLASTPol
Caption	Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry
Country	United States
Operator	University of Pennsylvania; NASA; Columbia University; Cardiff University
Mission type	Submillimeter telescope; polarimetry
Status	Active

BLASTPol is a balloon-borne submillimeter polarimeter developed to map polarized dust emission in star-forming regions and the interstellar medium. It combines large-aperture optics, cryogenic detectors, and polarimetric modulation to measure magnetic field morphology across molecular clouds, complementing observations from space telescopes and ground-based observatories. The project bridges technology demonstrators and legacy facilities by providing high-resolution, wide-field polarimetric maps that inform theories of star formation and magnetohydrodynamics.

Overview

BLASTPol emerged from collaborations involving University of Pennsylvania, NASA, Columbia University, Harvard University, Massachusetts Institute of Technology, Caltech, Jet Propulsion Laboratory, and international partners such as Cardiff University, University of Toronto, Max Planck Institute for Radio Astronomy, and University of British Columbia. The instrument targets submillimeter wavelengths near 250 μm, 350 μm, and 500 μm to probe cold dust emission in regions like the Vela Molecular Ridge, Carina Nebula, and the Vela C complex. BLASTPol complements missions and facilities including Herschel Space Observatory, Planck satellite, Atacama Large Millimeter/submillimeter Array, South Pole Telescope, James Clerk Maxwell Telescope, and SOFIA. Its flights have contributed to multiwavelength studies alongside campaigns from Spitzer Space Telescope, Chandra X-ray Observatory, Hubble Space Telescope, and Fermi Gamma-ray Space Telescope-related analyses. The program situates itself within the context of research by groups active in observational astrophysics, including work by the Harvard-Smithsonian Center for Astrophysics, European Southern Observatory, and the National Radio Astronomy Observatory.

Instrumentation and Design

BLASTPol's optical train uses a large primary mirror, reimaging optics, and feedhorn-coupled bolometer arrays developed from technology tested on instruments such as BOOMERanG, Archeops, and PILOT (balloon experiment). The detector arrays were fabricated using techniques pioneered at NASA Goddard Space Flight Center, Jet Propulsion Laboratory, and SRON Netherlands Institute for Space Research. Polarimetry is achieved with rotating half-wave plates and polarization-sensitive bolometers, informed by designs employed by POLARBEAR, BICEP, EBEX, and SPIDER (balloonborne experiment). Cryogenic systems maintain temperatures comparable to those used by the Planck High Frequency Instrument and employ refrigerators developed at Jet Propulsion Laboratory and Cardiff University laboratories. The gondola and pointing systems draw heritage from balloon programs run by Columbia Scientific Balloon Facility, NASA's Wallops Flight Facility, and the National Science Foundation Antarctic program, leveraging star cameras, gyroscopes, and reaction wheel assemblies used by teams at University of California, Berkeley, Princeton University, and University of Chicago.

Flight Operations and Campaigns

BLASTPol conducted Antarctic long-duration balloon flights launched from missions coordinated with British Antarctic Survey and National Science Foundation logistics, following operational models similar to BOOMERanG and BLAST (2003) missions. Campaigns have targeted austral summer windows to achieve extended integrations over regions connected to surveys by Herschel Gould Belt Survey, ATLASGAL, MALT90, and Hi-GAL. Teams have coordinated with ground facilities including McMurdo Station, Amundsen–Scott South Pole Station, and support from Raytheon, Lockheed Martin, and Ball Aerospace. Flight planning and recovery procedures incorporated expertise from the Columbia Scientific Balloon Facility, NASA Johnson Space Center, and international agencies such as CNES and UK Space Agency.

Scientific Objectives and Results

BLASTPol's primary scientific objectives include mapping magnetic field morphology in molecular clouds, constraining the role of magnetic fields in star formation, and characterizing dust grain alignment and polarization spectra. Publications have reported measurements of polarization fraction and angle dispersion in targets like Vela C, Lupus I, Vela Molecular Ridge, and the Carina Nebula, providing empirical constraints used by theorists at Princeton University, University of Cambridge, Yale University, and Northwestern University. Results have been compared with magnetohydrodynamic simulations produced by groups at Harvard University, Stanford University, University of Colorado Boulder, and the Max Planck Institute for Astrophysics to test theories from turbulent-regulated star formation models to ambipolar diffusion scenarios explored by researchers linked to the Institute for Advanced Study and Kavli Institute for Theoretical Physics. BLASTPol data have informed analyses related to polarization foregrounds in cosmic microwave background experiments such as BICEP2, Keck Array, Simons Observatory, and proposals for CMB-S4, and have been incorporated into multi-instrument papers with teams from Planck Collaboration, ACT (Atacama Cosmology Telescope), and SPTpol.

Data Analysis and Calibration

Data reduction pipelines for BLASTPol build on algorithms and software frameworks developed at University of Pennsylvania, University of Toronto, Jet Propulsion Laboratory, and NASA Ames Research Center, incorporating map-making tools used by groups behind Herschel, Planck, and ALMA. Calibration strategies cross-validate with celestial calibrators observed by Mars (planet), Jupiter, and compact sources cataloged in surveys from IRAS and WISE. Polarization calibration employs techniques used by POLARBEAR and EBEX teams, including instrument polarization characterization, Mueller matrix analysis, and null tests developed at Caltech and MIT. Data products have been archived and shared with collaborators at IPAC, NASA/IPAC Infrared Science Archive, and university repositories, enabling follow-up studies by groups at University of Michigan, Cornell University, University of Illinois Urbana–Champaign, and Rutgers University.

Collaborations and Funding

The BLASTPol collaboration spans institutions including University of Pennsylvania, Columbia University, Cardiff University, University of Toronto, University of British Columbia, Caltech, Harvard University, and Jet Propulsion Laboratory. Funding and logistical support have been provided by agencies such as NASA, the National Science Foundation, the European Research Council, the UK Research and Innovation, and institutional grants from participating universities. Industrial and technical partnerships have involved Ball Aerospace, Raytheon, Lockheed Martin, and specialized vendors associated with cryogenics and detector fabrication. BLASTPol team members have presented results at conferences organized by American Astronomical Society, International Astronomical Union, Cosmology Conference Series, and workshops hosted by Kavli Foundation and Simons Foundation.

Category:Balloon-borne telescopes Category:Submillimetre astronomy