306 citations · 2.5k across the 57 of their papers we have counts for
13 papers · 1 filter
Gravitational lensing time delay beyond the Shapiro/geometry split
Luca Teodori, Kfir Blum, Zhaoyu Bai
Time delays are a key observable in strong gravitational lensing systems. Their theoretical expression is usually written as a sum of a geometrical delay and a Shapiro delay, with…
Bracketing the soliton-halo relation of ultralight dark matter
Kfir Blum, Marco Gorghetto, Edward Hardy +1
In theories of ultralight dark matter, solitons form in the inner regions of galactic halos. The observational implications of these depend on the soliton mass. Various relations b…
AxionH0graphy: hunting for ultralight dark matter with cosmographic H signal
Kfir Blum, Luca Teodori
If ultralight boson fields exist, then vacuum misalignment populates them with nonzero relic abundance. For a broad range of particle mass the field condenses into fuzzy cores…
Host group degeneracy in gravitational lensing time delay determination of
Luca Teodori, Kfir Blum
Massive elliptical galaxies, that serve as lenses in gravitational lensing time delay measurements of the Hubble parameter , often reside in a host group. We consider degenera…
Comments on the mass sheet degeneracy in cosmography analyses
Luca Teodori, Kfir Blum, Emanuele Castorina +2
We make a number of comments regarding modeling degeneracies in strong lensing measurements of the Hubble parameter . The first point concerns the impact of weak lensing assoc…
Gravitational lensing tension from ultralight axion galactic cores
Kfir Blum, Luca Teodori
Gravitational lensing time delays offer an avenue to measure the Hubble parameter , with some analyses suggesting a tension with early-type probes of . The lensing measur…
Could quasar lensing time delays hint to a core component in halos, instead of H0 tension?
Kfir Blum, Emanuele Castorina, Marko Simonović
The time delay measured between the images of gravitationally lensed quasars probes a combination of the angular diameter distance to the source-lens system and the mass density pr…
Looking for ultralight dark matter near supermassive black holes
Nitsan Bar, Kfir Blum, Thomas Lacroix +1
Measurements of the dynamical environment of supermassive black holes (SMBHs) are becoming abundant and precise. We use such measurements to look for ultralight dark matter (ULDM),…
Ultra-light dark matter in disk galaxies
Nitsan Bar, Kfir Blum, Joshua Eby +1
Analytic arguments and numerical simulations show that bosonic ultra-light dark matter (ULDM) would form cored density distributions (`solitons') at the center of galaxies. ULDM so…
Galactic Rotation Curves vs. Ultra-Light Dark Matter: Implications of the Soliton -- Host Halo Relation
Nitsan Bar, Diego Blas, Kfir Blum +1
Bosonic ultra-light dark matter (ULDM) would form cored density distributions at the center of galaxies. These cores, seen in numerical simulations, admit analytic description as t…
CMB constraints on primordial black hole dark matter
Daniel Aloni, Kfir Blum, Raphael Flauger
We revisit cosmic microwave background (CMB) constraints on primordial black hole dark matter. Spectral distortion limits from COBE/FIRAS do not impose a relevant constraint. Planc…
Constraining Dark Matter-Baryon Scattering with Linear Cosmology
Cora Dvorkin, Kfir Blum, Marc Kamionkowski
We derive constraints on elastic scattering between baryons and dark matter using the cosmic microwave background (CMB) data from the Planck satellite and the Lyman-alpha forest da…
Perturbed Recombination from Dark Matter Annihilation
Cora Dvorkin, Kfir Blum, Matias Zaldarriaga
We show that dark matter annihilation around the time of recombination can lead to growing ionization fraction perturbations, that track the linear collapse of matter over-densitie…