Search Publications
Model-independent reconstruction of UV luminosity function and reionization epoch
Hazra, Dhiraj Kumar; Adak, Debabrata; Mitra, Sourav +1 more
We conduct a first comprehensive study of the Luminosity Function (LF) using a non-parametric approach. We use Gaussian Process to fit available luminosity data between redshifts z ∼ 2-8. Our free-form LF in the non-parametric approach rules out the conventional Schechter function model to describe the abundance-magnitude relation at redshifts z=3…
Wide binaries and modified gravity (MOG)
Moffat, J. W.
Wide binary stars are used to test the modified gravity called Scalar-Tensor-Vector Gravity or MOG. This theory is based on the additional gravitational degrees of freedom, the scalar field G = GN (1+α), where GN is Newton's constant, and the massive (spin-1 graviton) vector field ϕµ . The wide binaries have …
The glow of axion quark nugget dark matter. Part I. Large scale structures
Dolag, Klaus; Van Waerbeke, Ludovic; Sommer, Julian S. +5 more
Axion quark nuggets (AQN) are hypothetical, macroscopically large objects with a mass greater than a few grams and sub-micrometer size, formed during the quark-hadron transition. Originating from the axion field, they offer a possible resolution of the similarity between visible and dark components of the Universe, i.e. ΩDM ∼ Ωvisi…
Development of generic no-scale inflation
Wu, Lina; Shen, Jin-Ke; Li, Tianjun +1 more
We develop generalized no-scale supergravity models of inflation, and then study the corresponding cosmological predictions as well as the formation of primordial black holes (PBHs) and scalar-induced gravitational waves (SIGWs). With a new parameter 0 < a ≤ 1, the generalized no-scale supergravity provides the continuous connections among the …
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…
Putting all the X in one basket: Updated X-ray constraints on sub-GeV Dark Matter
Pinetti, Elena; Fornengo, Nicolao; Cirelli, Marco +2 more
Sub-GeV dark matter particles can annihilate or decay producing e ± pairs which upscatter the low-energy photon fields in the Galaxy and generate an X-ray emission (via the Inverse Compton effect). Using X-ray data from XMM-NEWTON, INTEGRAL, NUSTAR and SUZAKU, we derive new constraints on this class of dark matter (DM). In the annihilat…
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…
Updated constraints on primordial black hole evaporation
Korwar, Mrunal; Profumo, Stefano
The Hawking evaporation process, leading to the production of detectable particle species, constrains the abundance of light black holes, presumably of primordial origin. Here, we reconsider and correct constraints from soft gamma-ray observations, including of the gamma-ray line, at 511 keV, produced by electron-positron pair-annihilation, where …
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 …