Search Publications
Leveraging SN Ia spectroscopic similarity to improve the measurement of H 0
Filippenko, Alexei V.; Jones, David O.; Riess, Adam G. +7 more
Recent studies suggest spectroscopic differences explain a fraction of the variation in Type Ia supernova (SN Ia) luminosities after light-curve/color standardization. In this work, (i) we empirically characterize the variations of standardized SN Ia luminosities, and (ii) we use a spectroscopically inferred parameter, SIP, to improve the precisio…
Constraining cosmology with the Gaia-unWISE Quasar Catalog and CMB lensing: structure growth
Hogg, David W.; Rix, Hans-Walter; Eilers, Anna-Christina +4 more
We study the angular clustering of Quaia, a Gaia- and unWISE-based catalog of over a million quasars with an exceptionally well-defined selection function. With it, we derive cosmology constraints from the amplitude and growth of structure across cosmic time. We divide the sample into two redshift bins, centered at z = 1.0 and z = 2.1, and measure…
Stepped partially acoustic dark matter: likelihood analysis and cosmological tensions
Marques-Tavares, Gustavo; Buen-Abad, Manuel A.; Chacko, Zackaria +2 more
We generalize the recently proposed Stepped Partially Acoustic Dark Matter (SPartAcous) model by including additional massless degrees of freedom in the dark radiation sector. We fit SPartAcous and its generalization against cosmological precision data from the cosmic microwave background, baryon acoustic oscillations, large-scale structure, super…
Detecting dark compact objects in Gaia DR4: A data analysis pipeline for transient astrometric lensing searches
Kongsore, Marius; Chen, I. -Kai; Tilburg, Ken Van
The Gaia satellite is cataloging the astrometric properties of an unprecedented number of stars in the Milky Way with extraordinary precision. This provides a gateway for conducting extensive surveys of transient astrometric lensing events caused by dark compact objects. In this work, we establish a data analysis pipeline capable of searching for …
Exploring the effects of primordial non-Gaussianity at galactic scales
Famaey, Benoit; Ibata, Rodrigo; Stahl, Clément +2 more
While large scale primordial non-Gaussianity is strongly constrained by present-day data, there are no such constraints at Mpc scales. Here we investigate the effect of significant small-scale primordial non-Gaussianity on structure formation and the galaxy formation process with collisionless simulations: specifically, we explore four different t…
Astrometric microlensing of primordial black holes with Gaia
Rentala, Vikram; Verma, Himanshu
The Gaia space telescope allows for unprecedented accuracy for astrometric measurements of stars in the Galaxy. In this work, we explore the sensitivity of Gaia to detect primordial black hole (PBH) dark matter through the distortions that PBHs would create in the apparent trajectories of background stars, an effect known as astrometric microlensi…
White dwarf mass-radius relation in theories beyond general relativity
Alam, Khursid; Islam, Tousif
We explore the internal structures of the white dwarfs in two different modified theories of gravity: (i) scalar-tensor-vector gravity and (ii) beyond Horndeski theories of G 3 type. The modification of the gravitational force inside the white dwarf results in the modification of the mass and radius of the white dwarf. We use observatio…