Chicago – Kavli Institute Pre-Print Publications

Discovery of the Distant, Ultra-Faint Milky Way Satellite Aquarius IV with the Vera C. Rubin Observatory Early Data Preview 2

Posted by klaurent August 3, 2026August 5, 2026Chicago, This Week: Astrophysics

Kavli Affiliate: Alexander Ji | Summary:We present the discovery of Aquarius IV (Rubin J2201$-$0234) — the first ultra-faint Milky Way satellite to be identified using data from the Vera C. Rubin Observatory. This system was detected at $sim$8$σ$ significance using Rubin Early Data Preview 2 (EDP2) photometry and independently confirmed at $sim$6$σ$ significance in archival […]

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An upgraded frequency-selectable laser source (FLS) calibrator for CMB bandpass characterization

Posted by klaurent July 31, 2026August 5, 2026Chicago, This Week: Astrophysics

Kavli Affiliate: Jeffrey McMahon | Summary:One of the biggest challenges for Cosmic Microwave Background (CMB) experiments comes from the uncertainty in instrument bandpass calibration. Uncertainties in bandpass can limit foreground removal and spectral fitting, which are critical for inflationary and galaxy cluster measurements. CMB experiments currently use Fourier Transform Spectrometers (FTSes) to measure instrument bandpasses. […]

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Investigating the Observational Progenitor Mass Gap in the White Dwarf Initial-Final Mass Relation. I. Cluster Census and Characterization of the First White Dwarfs in the Gap

Posted by klaurent July 27, 2026August 5, 2026Chicago, This Week: Astrophysics

Kavli Affiliate: David W. Miller | Summary:In recent years, Gaia has been the primary driver of the expansion of the white dwarf (WD) initial-final mass relation (IFMR) in open clusters. The increased sample size has highlighted a pronounced observational gap at progenitor masses of $simeq2$–$2.7,M_odot$, with no spectroscopically confirmed cluster-member WDs in this range. Analysis […]

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BOSS-CLAM: Utilizing a Constrained Linear Absorption Model to Infer Stellar Parameters from BOSS Spectra

Posted by klaurent July 24, 2026Chicago

Kavli Affiliate: Alexander Ji | Summary:Large spectroscopic surveys require robust pipelines capable of inferring stellar parameters over a wide range of the Hertzsprung-Russell (HR) diagram from data of varying quality. SDSS-V is one such survey, where the data from the lower-resolution, optical BOSS spectrograph will provide a large dataset covering a wide range of Galactic […]

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Payne4GAIN: NLTE Corrections for Red Giants in Milky Way Mapper using H-Band Neural Network Emulators

Posted by klaurent July 24, 2026August 5, 2026Chicago

Kavli Affiliate: Alexander Ji | Summary:The majority of spectroscopic surveys assume local thermodynamic equilibrium (LTE) during the modeling of stellar spectra. This assumption begins to break down for luminous stars, like the red giants targeted by SDSS-V’s Milky Way Mapper Survey in its Galactic Genesis program. In this work, we present non-LTE (NLTE) abundances for […]

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Polarization vector conjugation in a photonic integrated circuit

Posted by klaurent July 23, 2026August 5, 2026Chicago

Kavli Affiliate: David W. Miller | Summary:We show how to perform polarization conjugation of light in a simple apparatus without any nonlinear optical materials, based on self-configuring Mach-Zehnder interferometers fed by a polarization splitter. This allows us to completely and automatically remove the polarization variations on a single beam or mode propagating through an optical […]

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Polarization vector conjugation in a photonic integrated circuit

Posted by klaurent July 23, 2026Chicago

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The High-Energy Light Isotope eXperiment (HELIX) Instrument

Posted by klaurent July 22, 2026August 5, 2026Chicago

Kavli Affiliate: Scott P. Wakely | Summary:The HELIX detector is a balloon-borne instrument designed to measure the flux of light (Z < 11) cosmic-ray isotopes. In this paper we describe the initial configuration of HELIX, optimized for measurements in the energy range from approximately 0.2 GeV per nucleon to beyond 3 GeV per nucleon. In […]

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The black hole S-matrix in gauge/gravity duality

Posted by klaurent July 20, 2026August 5, 2026Chicago

Kavli Affiliate: Emil Martinec | Summary:A variety of examples of gauge/gravity duality have a Coulomb branch for the gauge theory dynamics. We exploit this feature to construct an S-matrix, in which the initial state is a shell of branes converging on the origin of the Coulomb branch. In the gravitational dual, the shell of branes […]

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Probing the Cosmic Axion Background via Axion-Photon Conversion in Filaments

Posted by klaurent July 20, 2026August 5, 2026Chicago

Kavli Affiliate: Gordan Krnjaic | Summary:The cosmic axion background (CaB) is a hypothetical population of relativistic axions produced in the early universe. If the CaB is produced from dark matter decays, the axions in this population can convert to photons in the magnetic fields of cosmological filaments, resulting in an isotropic gamma ray background flux. […]

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