Canadian Hydrogen Intensity Mapping Experiment (CHIME) Pathfinder

Abstract

A pathfinder version of CHIME (the Canadian Hydrogen Intensity Mapping Experiment) is currently being commissioned at the Dominion Radio Astrophysical Observatory (DRAO) in Penticton, BC. The instrument is a hybrid cylindrical interferometer designed to measure the large scale neutral hydrogen power spectrum across the redshift range 0.8 to 2.5. The power spectrum will be used to measure the baryon acoustic oscillation (BAO) scale across this poorly probed redshift range where dark energy becomes a significant contributor to the evolution of the Universe. The instrument revives the cylinder design in radio astronomy with a wide field survey as a primary goal. Modern low-noise amplifiers and digital processing remove the necessity for the analog beamforming that characterized previous designs. The Pathfinder consists of two cylinders 37\,m long by 20\,m wide oriented north-south for a total collecting area of 1,500 square meters. The cylinders are stationary with no moving parts, and form a transit instrument with an instantaneous field of view of $\sim$100\,degrees by 1-2\,degrees. Each CHIME Pathfinder cylinder has a feedline with 64 dual polarization feeds placed every $\sim$30\,cm which Nyquist sample the north-south sky over much of the frequency band. The signals from each dual-polarization feed are independently amplified, filtered to 400-800\,MHz, and directly sampled at 800\,MSps using 8 bits. The correlator is an FX design, where the Fourier transform channelization is performed in FPGAs, which are interfaced to a set of GPUs that compute the correlation matrix. The CHIME Pathfinder is a 1/10th scale prototype version of CHIME and is designed to detect the BAO feature and constrain the distance-redshift relation.

20 pages, 12 figures. submitted to Proc. SPIE, Astronomical Telescopes + Instrumentation (2014)

References in corpus (4)

• A bright millisecond radio burst of extragalactic origin
• Baryon Acoustic Oscillations in the Ly-α forest of BOSS quasars
• Measurement of 21 cm brightness fluctuations at z ~ 0.8 in cross-correlation
• Possibility of Precise Measurement of the Cosmological Power Spectrum With a Dedicated 21cm Survey After Reionization

Cited by in corpus (19)

• Probing Galactic Halos with Fast Radio Bursts
• Implications of a "Fast Radio Burst" from a Galactic Magnetar
• Cosmology-independent estimate of the fraction of baryon mass in the IGM from fast radio burst observations
• Two long-term intermittent pulsars discovered in the PALFA Survey
• Precise measurements of inflationary features with 21 cm observations
• Spherical Harmonic Analyses of Intensity Mapping Power Spectra
• Mode switching and oscillations in PSR B1828-11
• Probing motion of fast radio burst sources by timing strongly lensed repeaters
• Measuring the growth of structure with intensity mapping surveys
• Analyzing the cosmic variance limit of remote dipole measurements of the cosmic microwave background using the large-scale kinetic Sunyaev Zel'dovich effect
• Small-scale structure and the Lyman-$\alpha$ forest baryon acoustic oscillation feature
• The Ooty Wide Field Array
• Modelling redshift-space distortion in the post-reionization $\mathrm{HI}$ 21-cm power spectrum
• Measuring HERA's primary beam in-situ: methodology and first results
• The Astrophysical Consequences of Intervening Galaxy Gas on Fast Radio Bursts
• Physics Beyond The Standard Model with Circular Polarization in the CMB and CMB-21cm Cross-Correlation
• Simulated foreground predictions for HI at z = 3.35 with the Ooty Wide Field Array: I. Instrument and the foregrounds
• Detection of Cosmic Structures using the Bispectrum Phase. I. Mathematical Foundations
• An Integrated System at the Bleien Observatory for Mapping the Galaxy