Search Publications
Imaging and Spectroscopic Observations of Magnetic Reconnection and Chromospheric Evaporation in a Solar Flare
Reeves, Katharine K.; Chen, Bin; Liu, Wei +5 more
Magnetic reconnection is believed to be the dominant energy release mechanism in solar flares. The standard flare model predicts both downward and upward outflow plasmas with speeds close to the coronal Alfvén speed. Yet, spectroscopic observations of such outflows, especially the downflows, are extremely rare. With observations of the newly launc…
SN 2010jl: Optical to Hard X-Ray Observations Reveal an Explosion Embedded in a Ten Solar Mass Cocoon
Hailey, Charles J.; Filippenko, Alexei V.; Cenko, S. Bradley +24 more
Some supernovae (SNe) may be powered by the interaction of the SN ejecta with a large amount of circumstellar matter (CSM). However, quantitative estimates of the CSM mass around such SNe are missing when the CSM material is optically thick. Specifically, current estimators are sensitive to uncertainties regarding the CSM density profile and the e…
Velocity Dispersions and Dynamical Masses for a Large Sample of Quiescent Galaxies at z > 1: Improved Measures of the Growth in Mass and Size
Ellis, Richard S.; Belli, Sirio; Newman, Andrew B.
We present Keck LRIS spectroscopy for a sample of 103 massive (M > 1010.6 M ⊙) galaxies with redshifts 0.9 < z < 1.6. Of these, 56 are quiescent with high signal-to-noise absorption line spectra, enabling us to determine robust stellar velocity dispersions for the largest sample yet available beyond a redshift of 1. …
Whistler Mode Waves and the Electron Heat Flux in the Solar Wind: Cluster Observations
Maksimovic, M.; Alexandrova, O.; de Conchy, Y. +5 more
The nature of the magnetic field fluctuations in the solar wind between the ion and electron scales is still under debate. Using the Cluster/STAFF instrument, we make a survey of the power spectral density and of the polarization of these fluctuations at frequencies f in [1, 400] Hz, during five years (2001-2005), when Cluster was in the free sola…
BBN and the CMB constrain light, electromagnetically coupled WIMPs
Nollett, Kenneth M.; Steigman, Gary
In the presence of a light weakly interacting massive particle (WIMP; mχ≲30 MeV), there are degeneracies among the nature of the WIMP (fermion or boson), its couplings to the standard-model particles (electromagnetic or to neutrinos only), the WIMP mass mχ, and the number of equivalent neutrinos beyond the standard model ΔN
A 1010 Solar Mass Flow of Molecular Gas in the A1835 Brightest Cluster Galaxy
Fabian, A. C.; Egami, E.; Combes, F. +17 more
We report ALMA Early Science observations of the A1835 brightest cluster galaxy (BCG) in the CO (3-2) and CO (1-0) emission lines. We detect 5 × 1010 M ⊙ of molecular gas within 10 kpc of the BCG. Its ensemble velocity profile width of ~130 km s-1 FWHM is too narrow for the molecular clouds to be supported in the g…
ALMA reveals the feeding of the Seyfert 1 nucleus in NGC 1566
Tacconi, L. J.; Hunt, L. K.; Krips, M. +9 more
We report ALMA observations of CO(3-2) emission in the Seyfert 1 galaxy NGC 1566, at a spatial resolution of 25 pc. Our aim is to investigate the morphology and dynamics of the gas inside the central kpc, and to probe nuclear fueling and feedback phenomena. NGC 1566 has a nuclear bar of 1.7 kpc radius and a conspicuous grand design spiral starting…
Elemental Compositions of Two Extrasolar Rocky Planetesimals
Koester, D.; Zuckerman, B.; Xu, S. +2 more
We report Keck/HIRES and Hubble Space Telescope/COS spectroscopic studies of extrasolar rocky planetesimals accreted onto two hydrogen atmosphere white dwarfs, G29-38 and GD 133. In G29-38, eight elements are detected, including C, O, Mg, Si, Ca, Ti, Cr, and Fe while in GD 133, O, Si, Ca, and marginally Mg are seen. These two extrasolar planetesim…
The Lyman Alpha Reference Sample. II. Hubble Space Telescope Imaging Results, Integrated Properties, and Trends
Verhamme, Anne; Cannon, John M.; Hayes, Matthew +16 more
We report new results regarding the Lyα output of galaxies, derived from the Lyman Alpha Reference Sample, and focused on Hubble Space Telescope imaging. For 14 galaxies we present intensity images in Lyα, Hα, and UV, and maps of Hα/Hβ, Lyα equivalent width (EW), and Lyα/Hα. We present Lyα and UV radial light profiles and show they are well-fitted…
Extensive HST ultraviolet spectra and multiwavelength observations of SN 2014J in M82 indicate reddening and circumstellar scattering by typical dust
Fox, O. D.; Zheng, W.; Challis, P. +20 more
SN 2014J in M82 is the closest detected Type Ia supernova (SN Ia) in at least 28 yr and perhaps in 410 yr. Despite its small distance of 3.3 Mpc, SN 2014J is surprisingly faint, peaking at V = 10.6 mag, and assuming a typical SN Ia luminosity, we infer an observed visual extinction of AV = 2.0 ± 0.1 mag. But this picture, with RV