Receiver Lab Talks: 2026
Questions: Edward Tong
Time: Thursday 12:00 PM EST/EDT
Where: M-340/Zoom
| Date | Speaker | Title | Summary |
|---|---|---|---|
| Feb. 19 | Pranav Sanghavi CfA |
Designing and Commissioning the Coherent All-Sky Monitor | Fast Radio Bursts (FRBs) are millisecond-duration radio pulses whose physical origin remains uncertain, yet their dispersion measures (DMs) provide a uniquely sensitive probe of diffuse ionized gas in and around galaxies. At cosmological distances, the intergalactic medium dominates the DM budget, whereas for nearby events (#500 Mpc), the Milky Way halo and the host-galaxy interstellar and circumgalactic media (ISM, CGM) can contribute much of the signal. Systematic surveys of this local-Universe regime have been limited by the rarity of bright nearby FRBs and by the narrow instantaneous fields of view of most facilities. In this talk I will talk about the Coherent All-Sky Monitor (CASM), an upcoming dense, 256-element dual-polarized aperture array being deployed at the Owens Valley Radio Observatory to search for dispersed FRB pulses in the relatively quiet 375-500 MHz band. CASM combines a 125 MHz bandwidth, a system-equivalent flux density of 2-3 kJy, and an unprecedented ~10,000 sq deg instantaneous field of view, enabling detection of rare FRBs at z # 0.1 that are inaccessible to existing instruments. The array is laid out as 43 rows of six printed-circuit-board dipoles on a ground screen and digitizes signals at 250 Msps. Packetized data are aggregated at ~390 Gb/s and processed on GPU servers for beamforming, correlation, and real-time FRB searches. CASM is designed to detect #100 FRBs per year within <500 Mpc and, with planned outrigger stations, to localize bursts to ~5 arcsec for host-galaxy identification. In parallel, its all-sky cadence will enable discovery of new Galactic radio phenomena and long-term monitoring of repeaters. This uniquely local sample will directly constrain the baryonic content and structure of the Milky Way halo and the CGM of nearby galaxies, distinguish between halo-gas and feedback models, and provide a scalable technology pathfinder toward next-generation omniscope-class radio instruments. In this talk I will detail our progress so far and plans for the coming year. |
| Feb. 5 | Nimesh Patel CfA |
The Greenland Telescope: Current Status and Near-Term Science | The Greenland Telescope (GLT) has been operational at Pituffik Space Base since 2018, contributing to Event Horizon Telescope and Global Millimeter Very Long Baseline Interferometry observations of M87 and other active galactic nuclei. While plans to relocate the telescope to the Summit site are currently on hold, the GLT is entering a phase of increased scientific activity, including regular monitoring of M87 at 86 and 230 GHz. Preparations are also underway for single-dish science at 3 mm, with proposals for new instrumentation. This talk will summarize the current status of the GLT, highlight engineering work completed over the past six months, and outline ongoing projects and near-term scientific plans. |
| Jan. 29 | Mark Reid CfA |
Mapping the Mily Way in 3D | The Bar and Spiral Structure Legacy (BeSSeL) Survey uses Very Long Baseline Interferometry to provide trigonometric parallax measurements for massive, young stars across the entire Milky Way. We have measured about 200 parallaxes with precision of order +/-10 microarcseconds. These accurately trace the spiral structure of the Milky Way, and allow estimation of the distance to its center, its rotation curve, and the location of the Sun. Also, we have developed a Bayesian approach to leverage these results to estimate distances to thousands of sources from surveys based only on Galactic coordinates and LSR velocities. Using this program we can make a realistic visualization of the Milky Way. |
Previous presentations available here:
CfA managed Google Drive
