Search Publications
CMB Polarization B-mode Delensing with SPTpol and Herschel
Bock, J. J.; Chiang, H. C.; Conley, A. +60 more
We present a demonstration of delensing the observed cosmic microwave background (CMB) B-mode polarization anisotropy. This process of reducing the gravitational-lensing-generated B-mode component will become increasingly important for improving searches for the B modes produced by primordial gravitational waves. In this work, we delens B-mode map…
iPTF 16asu: A Luminous, Rapidly Evolving, and High-velocity Supernova
Cenko, S. B.; Sollerman, J.; Hurley, K. +23 more
Wide-field surveys are discovering a growing number of rare transients whose physical origin is not yet well understood. Here we present optical and UV data and analysis of intermediate Palomar Transient Factory (iPTF) 16asu, a luminous, rapidly evolving, high-velocity, stripped-envelope supernova (SN). With a rest-frame rise time of just four day…
Observational Signatures of Transverse Magnetohydrodynamic Waves and Associated Dynamic Instabilities in Coronal Flux Tubes
Yokoyama, T.; Antolin, P.; De Moortel, I. +1 more
Magnetohydrodynamic (MHD) waves permeate the solar atmosphere and constitute potential coronal heating agents. Yet, the waves detected so far may be but a small subset of the true existing wave power. Detection is limited by instrumental constraints but also by wave processes that localize the wave power in undetectable spatial scales. In this stu…
How Do Stars Gain Their Mass? A JCMT/SCUBA-2 Transient Survey of Protostars in Nearby Star-forming Regions
Herczeg, Gregory J.; Kwon, Woojin; Soam, Archana +55 more
Most protostars have luminosities that are fainter than expected from steady accretion over the protostellar lifetime. The solution to this problem may lie in episodic mass accretion—prolonged periods of very low accretion punctuated by short bursts of rapid accretion. However, the timescale and amplitude for variability at the protostellar phase …
The Geometry of the Sagittarius Stream from Pan-STARRS1 3π RR Lyrae
Chambers, Kenneth C.; Rix, Hans-Walter; Belokurov, Vasily +11 more
We present a comprehensive and precise description of the Sagittarius (Sgr) stellar stream’s 3D geometry as traced by its old stellar population. This analysis draws on the sample of ∼44,000 RR Lyrae (RRab) stars from the Pan-STARRS1 (PS1) 3π survey, which is ∼ 80 % complete and ∼ 90 % pure within 80 kpc, and extends to ≳ 120 {kpc} with a distance…
Microflare Heating of a Solar Active Region Observed with NuSTAR, Hinode/XRT, and SDO/AIA
Krucker, Säm; White, Stephen M.; Grefenstette, Brian W. +7 more
NuSTAR is a highly sensitive focusing hard X-ray (HXR) telescope and has observed several small microflares in its initial solar pointings. In this paper, we present the first joint observation of a microflare with NuSTAR and Hinode/XRT on 2015 April 29 at ∼11:29 UT. This microflare shows the heating of material to several million Kelvin, observed…
Solar Active Region Coronal Jets. II. Triggering and Evolution of Violent Jets
Panesar, Navdeep K.; Moore, Ronald L.; Sterling, Alphonse C. +2 more
We study a series of X-ray-bright, rapidly evolving active region coronal jets outside the leading sunspot of AR 12259, using Hinode/X-ray telescope, Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI), and Interface Region Imaging Spectrograph (IRIS) data. The detailed evolution of such r…
Chemistry and Kinematics of the Late-forming Dwarf Irregular Galaxies Leo A, Aquarius, and Sagittarius DIG
Skillman, Evan D.; Cole, Andrew A.; Held, Enrico V. +5 more
We present Keck/DEIMOS spectroscopy of individual stars in the relatively isolated Local Group dwarf galaxies Leo A, Aquarius, and the Sagittarius dwarf irregular galaxy. The three galaxies—but especially Leo A and Aquarius—share in common delayed star formation histories (SFHs) relative to many other isolated dwarf galaxies. The stars in all thre…
On the Connection between Turbulent Motions and Particle Acceleration in Galaxy Clusters
Paltani, S.; Gastaldello, F.; Tramacere, A. +5 more
Giant radio halos are megaparsec-scale diffuse radio sources associated with the central regions of galaxy clusters. The most promising scenario to explain the origin of these sources is that of turbulent re-acceleration, in which MeV electrons injected throughout the formation history of galaxy clusters are accelerated to higher energies by turbu…
The Sizes and Depletions of the Dust and Gas Cavities in the Transitional Disk J160421.7-213028
Dong, Ruobing; Ohashi, Nagayoshi; Tamura, Motohide +18 more
We report ALMA Cycle 2 observations of 230 GHz (1.3 mm) dust continuum emission, and 12CO, 13CO, and C18O J = 2-1 line emission, from the Upper Scorpius transitional disk [PZ99] J160421.7-213028, with an angular resolution of ∼0\buildrel{\prime\prime}\over{.} 25 (35 au). Armed with these data and existing H-band sc…