Search Publications
Joining Bits and Pieces of Reionization History
Finelli, Fabio; Paoletti, Daniela; Hazra, Dhiraj Kumar +1 more
Cosmic microwave background (CMB) temperature and polarization anisotropies from Planck have estimated a lower value of the optical depth to reionization (τ ) compared to WMAP. A significant period in the reionization history would then fall within 6 <redshift(z )<10 , where detection of galaxies with Hubble frontier fields program and indep…
Primordial Black Holes as a Dark Matter Candidate Are Severely Constrained by the Galactic Center 511 keV γ -Ray Line
Laha, Ranjan
We derive the strongest constraint on the fraction of dark matter that can be composed of low mass primordial black holes by using the observation of the Galactic Center 511 keV γ -ray line. Primordial black holes of masses ≲1015 kg will evaporate to produce e± pairs. The positrons will lose energy in the Galactic Center, bec…
Constraining Primordial Black Hole Abundance with the Galactic 511 keV Line
DeRocco, William; Graham, Peter W.
Models in which dark matter consists entirely of primordial black holes (PBHs) with masses around 1 017 g are currently unconstrained. However, if PBHs are a component of the Galactic dark matter density, they will inject a large flux of energetic particles into the Galaxy as they radiate. Positrons produced by these black holes will su…
Cosmological Constraints from Multiple Probes in the Dark Energy Survey
Bacon, D.; Bechtol, K.; Challis, P. +161 more
The combination of multiple observational probes has long been advocated as a powerful technique to constrain cosmological parameters, in particular dark energy. The Dark Energy Survey has measured 207 spectroscopically confirmed type Ia supernova light curves, the baryon acoustic oscillation feature, weak gravitational lensing, and galaxy cluster…
Upper Bound of Neutrino Masses from Combined Cosmological Observations and Particle Physics Experiments
Lahav, Ofer; Manera, Marc; Loureiro, Arthur +9 more
We investigate the impact of prior models on the upper bound of the sum of neutrino masses, ∑mν . Using data from the large scale structure of galaxies, cosmic microwave background, type Ia supernovae, and big bang nucleosynthesis, we argue that cosmological neutrino mass and hierarchy determination should be pursued using exact models,…
Hunting Axion Dark Matter with Protoplanetary Disk Polarimetry
Tazaki, Ryo; Toma, Kenji; Fujita, Tomohiro
We find that the polarimetric observations of protoplanetary disks are useful to search for ultralight axion dark matter. Axion dark matter predicts the rotation of the linear polarization plane of propagating light, and protoplanetary disks are ideal targets to observe it. We show that a recent observation puts the tightest constraint on the axio…
X-Ray Signatures of Axion Conversion in Magnetic White Dwarf Stars
Safdi, Benjamin R.; Dessert, Christopher; Long, Andrew J.
White dwarf (WD) stars may radiate keV-energy axions produced in their stellar cores. This has been extensively studied as an extra channel by which WDs may cool, with some analyses even suggesting that axions can help explain the observed WD luminosity function. We show that the radiated axions may convert into x rays in the strong magnetic field…
New Test of Lorentz Invariance Using the MICROSCOPE Space Mission
Métris, Gilles; Rodrigues, Manuel; Touboul, Pierre +11 more
We use data from the T-SAGE instrument on board the MICROSCOPE space mission to search for Lorentz violation in matter-gravity couplings as described by the Lorentz violating standard model extension (SME) coefficients (a¯ eff)µw , where (µ =T , X , Y , Z ) and (w =e , p , n ) for the electron, proton, …
LISA Pathfinder Performance Confirmed in an Open-Loop Configuration: Results from the Free-Fall Actuation Mode
Mendes, L.; Russano, G.; Nofrarias, M. +75 more
We report on the results of the LISA Pathfinder (LPF) free-fall mode experiment, in which the control force needed to compensate the quasistatic differential force acting on two test masses is applied intermittently as a series of "impulse" forces lasting a few seconds and separated by roughly 350 s periods of true free fall. This represents an al…
Beyond the Required LISA Free-Fall Performance: New LISA Pathfinder Results down to 20 µ Hz
Mendes, L.; Russano, G.; Lloro, I. +75 more
In the months since the publication of the first results, the noise performance of LISA Pathfinder has improved because of reduced Brownian noise due to the continued decrease in pressure around the test masses, from a better correction of noninertial effects, and from a better calibration of the electrostatic force actuation. In addition, the ava…