Spider (polarimeter)

Summary

Spider is a balloon-borne experiment designed to search for primordial gravitational waves imprinted on the cosmic microwave background (CMB). Measuring the strength of this signal puts limits on inflationary theory.

Spider
Altitude36 km (118,000 ft) Edit this at Wikidata
Wavelength3, 2, 1.1 mm (100, 150, 273 GHz)
First light1 January 2015 Edit this on Wikidata
Telescope styleballoon-borne telescope
cosmic microwave background experiment
radio telescope Edit this on Wikidata
Number of telescopesEdit this on Wikidata
Mass3.5 t (3,500 kg) Edit this at Wikidata
Websitespider.princeton.edu Edit this at Wikidata
Spider on the launch vehicle
The Spider experiment hanging from the launch vehicle prior to its first flight over Antarctica.

The Spider instrument consists of six degree-resolution telescopes cooled to liquid Helium temperature (4 K) which observe at frequencies of 100 GHz, 150 GHz, and 280 GHz (corresponding to wavelengths of 3 mm, 2 mm, and 1.1 mm). Each telescope is coupled to a polarisation-sensitive transition-edge bolometer (TES) array cooled to 300 mK. Spider was the first instrument to successfully demonstrate time-domain multiplexed TES detectors in a space-like environment. At the time of the first flight over Antarctica in 2015, Spider was the most sensitive microwave instrument ever made.[1][2]

The primary science goals include:

  1. characterization of the curl-free component of the CMB polarization on the largest scales
  2. searching for the signature of inflationary gravitational waves in the CMB polarization
  3. characterization of the polarization properties of the emission from our own Milky Way Galaxy

The first balloon flight of the experiment launched in January 2015 from McMurdo Station, Antarctica, with support from NASA's Columbia Scientific Balloon Facility. This Long Duration Balloon flight lasted for about 17 days, mapping about 10% of the full sky. The data from this flight produced high signal-to-noise images of the intensity and linear polarization of the Cosmic Microwave Background, with noise levels 3—5 times lower than the Planck spacecraft in the same region of the sky, resulting in precise measurements of the CMB and Galactic foreground radiation, as well as a robust limit on the cosmological tensor-to-scalar ratio. Further flights planned for successive seasons enable upgrades and changes to the modular telescope, increased frequency coverage and depth.

References edit

  1. ^ Shaw, E. C.; et al. (2020). "Design and pre-flight performance of SPIDER 280 GHZ receivers". In Zmuidzinas, Jonas; Gao, Jian-Rong (eds.). Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy X. p. 173. arXiv:2012.12407. doi:10.1117/12.2562941. ISBN 9781510636934. S2CID 229363672.
  2. ^ Collaboration, SPIDER; et al. (2021). "A Constraint on Primordial $B$-Modes from the First Flight of the SPIDER Balloon-Borne Telescope". arXiv:2103.13334 [astro-ph.CO].

External links edit

  • Group Research Homepage
  • Spider Homepage
  • Spider 2014/15 campaign blog
  • The Spider Collaboration, "A Constraint on Primordial B-Modes from the First Flight of the SPIDER Balloon-Borne Telescope"