Search Publications
Neutral Hydrogen Structures Trace Dust Polarization Angle: Implications for Cosmic Microwave Background Foregrounds
Peek, J. E. G.; Hill, J. Colin; Clark, S. E. +2 more
Using high-resolution data from the Galactic Arecibo L-Band Feed Array HI (GALFA-Hi) survey, we show that linear structure in Galactic neutral hydrogen (Hi) correlates with the magnetic field orientation implied by Planck 353 GHz polarized dust emission. The structure of the neutral interstellar medium is more tightly coupled to the magnetic field…
Evidence of Lensing of the Cosmic Microwave Background by Dark Matter Halos
Hilton, Matt; Hasselfield, Matthew; Bond, J. Richard +41 more
We present evidence of the gravitational lensing of the cosmic microwave background by 1013 solar mass dark matter halos. Lensing convergence maps from the Atacama Cosmology Telescope Polarimeter (ACTPol) are stacked at the positions of around 12 000 optically selected CMASS galaxies from the SDSS-III/BOSS survey. The mean lensing signa…
Evidence of the Missing Baryons from the Kinematic Sunyaev-Zeldovich Effect in Planck Data
Wang, Wenting; Ma, Yin-Zhe; Herranz, Diego +4 more
We estimate the amount of the missing baryons detected by the Planck measurements of the cosmic microwave background in the direction of central galaxies (CGs) identified in the Sloan galaxy survey. The peculiar motion of the gas inside and around the CGs unveils values of the Thomson optical depth τT in the range 0.2 - 2 ×1 0-4
Excitation of Chirping Whistler Waves in a Laboratory Plasma
Bortnik, J.; Thorne, R. M.; Van Compernolle, B. +3 more
Whistler mode chorus emissions with a characteristic frequency chirp are important magnetospheric waves, responsible for the acceleration of outer radiation belt electrons to relativistic energies and also for the scattering loss of these electrons into the atmosphere. Here, we report on the first laboratory experiment where whistler waves exhibit…
Detection of B-Mode Polarization at Degree Angular Scales by BICEP2
Ade, P. A. R.; Bock, J. J.; Hildebrandt, S. R. +45 more
We report results from the BICEP2 experiment, a cosmic microwave background (CMB) polarimeter specifically designed to search for the signal of inflationary gravitational waves in the B-mode power spectrum around ℓ∼80. The telescope comprised a 26 cm aperture all-cold refracting optical system equipped with a focal plane of 512 antenna coupled tra…
Unidentified Line in X-Ray Spectra of the Andromeda Galaxy and Perseus Galaxy Cluster
Boyarsky, A.; Franse, J.; Iakubovskyi, D. +1 more
We report a weak line at 3.52 ±0.02 keV in x-ray spectra of the Andromeda galaxy and the Perseus galaxy cluster observed by the metal-oxide-silicon (MOS) and p -n (PN) CCD cameras of the XMM-Newton telescope. This line is not known as an atomic line in the spectra of galaxies or clusters. It becomes stronger towards the centers of the objects; is …
Indications of a Late-Time Interaction in the Dark Sector
Melchiorri, Alessandro; Said, Najla; Salvatelli, Valentina +2 more
We show that a general late-time interaction between cold dark matter and vacuum energy is favored by current cosmological data sets. We characterize the strength of the coupling by a dimensionless parameter qV that is free to take different values in four redshift bins from the primordial epoch up to today. This interacting scenario is…
Evidence for Massive Neutrinos from Cosmic Microwave Background and Lensing Observations
Battye, Richard A.; Moss, Adam
We discuss whether massive neutrinos (either active or sterile) can reconcile some of the tensions within cosmological data that have been brought into focus by the recently released Planck data. We point out that a discrepancy is present when comparing the primary CMB and lensing measurements both from the CMB and galaxy lensing data using CFHTLe…
Neutrinos Help Reconcile Planck Measurements with the Local Universe
Hu, Wayne; Wyman, Mark; Rudd, Douglas H. +1 more
Current measurements of the low and high redshift Universe are in tension if we restrict ourselves to the standard six-parameter model of flat ΛCDM. This tension has two parts. First, the Planck satellite data suggest a higher normalization of matter perturbations than local measurements of galaxy clusters. Second, the expansion rate of the Univer…
Firehose and Mirror Instabilities in a Collisionless Shearing Plasma
Kunz, Matthew W.; Schekochihin, Alexander A.; Stone, James M.
Hybrid-kinetic numerical simulations of firehose and mirror instabilities in a collisionless plasma are performed in which pressure anisotropy is driven as the magnetic field is changed by a persistent linear shear S. For a decreasing field, it is found that mostly oblique firehose fluctuations grow at ion Larmor scales and saturate with energies …