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Events on Friday, January 26th, 2024

Preliminary Exam
Developing an Analysis Pipeline, and mm/sub-mm Spectrometer for a Novel Balloon-Borne Intensity Mapping Experiment.
Time: 1:00 pm - 3:00 pm
Place: B343 Sterling or
Speaker: Faizah Karim Siddique, Physics Graduate Student
Abstract: This talk is broken down into two sections focusing on the two different projects I am working on:

The first section on my talk will be on my development of the analysis pipeline for the upcoming EXperiment for Cryogenic Large-Aperture Intensity Mapping (EXCLAIM), which is proposed to have its first flight in Fall 2024. EXCLAIM is a balloon-borne cryogenic telescope that will perform line intensity mapping to study star formation rate history, and galaxy evolution. Line intensity mapping is a novel technique that detects the sum of all sources emitting in a particular spectral line in a given pixel. These are 3-dimensional maps that probe emissions at different redshift slices simultaneously. EXCLAIM will be sensitive over the 420–540 GHz frequency range. The main resonance lines of interest are the singly ionized carbon ([CII] or C+) over the redshift range z = 2.5–3.5, and multiple transition lines of carbon monoxide (CO) over z ≤ 1 that will be both a science target and a foreground line for [CII]. The current observing plan includes a survey of a 100 deg^2 region in the Galactic plane, and a 320 deg^2 region outside the Galactic plane that coincides with Stripe−82. I will present my current work on the analysis pipeline which involves constructing line intensity maps from simulated time-ordered-data. My simulated maps will include signals from [CII], (CO) interloping lines, Milky Way Foregrounds, atmospheric effects, and numerous instrumental effects including white-noise, 1/f-noise, and beam convolution. I plan to perform mode cleaning using Single-Value-Decomposition to attempt to de-noise my simulated intensity maps and report on any [CII] signal loss that will need to be accounted for. This work will help form the foundation for cleaning/analyzing EXCLAIM data when available.

The second section of my talk will focus on my work on developing and fabricating a DC voltage-biased Josephson Junction Radiator (JJR) calibrator to be used as both in-flight internal calibrators and laboratory testbed devices for future orbital, and sub-orbital astrophysics missions like EXCLAIM. In theory, JJRs can serve as calibrators for superconducting, non-superconducting detectors, and heterodyne instrumentation/detection and therefore can be useful for a wide variety of experiments over the mm and sub-mm wavelength range. I initially plan to study the characteristics of the JJRs using kinetic inductance detectors (KIDs) that I will also be fabricating. I will fabricate both devices lithographically on the same chip. I will implement designs that the McDermott Quantum Computing group at UW-Madison have developed. Antennas will also be included in the device’s design with the purpose of coupling the radiation/calibration source to the instrument and the detector optics. One promising antenna design is the lenslet-coupled antenna, which is a lens formed from a combination of both a hemisphere and a dielectric extension integrated with a lithographed planar antenna. I plan to implement the sinuous lenslet-coupled antenna design, which is a log-periodic antenna.
Host: Peter Timbie
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NPAC (Nuclear/Particle/Astro/Cosmo) Forum
The flavor composition of high-energy cosmic neutrinos: towards high statistics and ultra-high energies
Time: 2:00 pm - 3:00 pm
Place: Chamberlin Hall 5280
Speaker: Mauricio Bustamante, Niels Bohr Institute, University of Copenhagen
Abstract: The flavor composition of high-energy cosmic neutrinos, i.e., the proportion of neutrinos of different flavor in their flux---electron, muon, and tau---is a versatile observable to test astrophysics and particle physics. For astrophysics, it allows us to identify the neutrino production process and so narrow down the identity of their sources. For fundamental physics, it allows us to probe physics beyond the Standard Model at hitherto untested energies. Yet, so far, the experimental difficulties involved in measuring flavor composition in IceCube have hampered its physics reach. Fortunately, this may be for not much longer, thanks to upcoming, larger neutrino telescopes. I will show state-of-the-art forecasts for the measurement of the flavor composition of TeV-PeV cosmic neutrinos in the next two decades using the combined detection by multiple neutrino telescopes. Together, they could enable measurements of the energy dependence of the flavor composition---revealing changes in the neutrino production process---and of its directional dependence---revealing flavor asymmetries in the high-energy neturino sky. I will conclude by proposing novel techniques to extend flavor-composition measurements to ultra-high energies, beyond 100 PeV, using large-scale radio-detection in IceCube-Gen2 and GRAND.
Host: Ke Fang
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Physics Department Colloquium
Gravitational-wave astronomy with LIGO-Virgo-KAGRA
Time: 3:30 pm - 4:30 pm
Place: 2241 Chamberlin Hall
Speaker: Patrick Brady, University of Wisconsin-Milwaukee
Abstract: Brady will describe the current state of ground-based, gravitational-wave astronomy and the prospects for the future. He will present highlights from LIGO-Virgo-KAGRA observations including recent findings on compact object mergers. Gravitational waves from black-hole-binary mergers are now being detected about twice per week and astronomers are eagerly awaiting the next multi-messenger event. Over the next decade, a sequence of upgrades will more than double the amplitude sensitivity of the most sensitive gravitational-wave detectors and increase the rate of compact binary detections by about a factor of ten. Brady will discuss how the improved signal-to-noise ratio will also enable unprecedented measurements of masses, spins, and other properties of black holes and neutron stars in binary systems. The upgrades may also bring the discovery of other gravitational-wave sources. The talk will end with a discussion of future directions for ground-based gravitational-wave astronomy, highlighting the opportunities for multimessenger astronomy in the early 2030s and how operations of the current detector network can dovetail with operations of next-generation facilities such as Cosmic Explorer and Einstein Telescope.
Host: Justin Vandenbroucke
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