Search Publications
A Comparison of the Intensities and Energies of Gradual Solar Energetic Particle Events with the Dynamical Properties of Associated Coronal Mass Ejections
Vourlidas, A.; Kahler, S. W.
Gradual solar energetic particle (SEP) events observed at 1 AU are produced by shocks driven by coronal mass ejections (CMEs). Characterizations of the remotely imaged CMEs and of their associated SEP events observed in situ can be used to increase our ability to forecast SEP events and to understand better the physical connections between the two…
Herschel/SPIRE Submillimeter Spectra of Local Active Galaxies
Wilson, Christine D.; Baes, Maarten; Cormier, Diane +11 more
We present the submillimeter spectra from 450 to 1550 GHz of 11 nearby active galaxies observed with the SPIRE Fourier Transform Spectrometer (SPIRE/FTS) on board Herschel. We detect CO transitions from J up = 4 to 12, as well as the two [C I] fine structure lines at 492 and 809 GHz and the [N II]1461 GHz line. We used radiative transfe…
Helioseismic calibration of the equation of state and chemical composition in the solar convective envelope
Vorontsov, S. V.; Baturin, V. A.; Ayukov, S. V. +1 more
Accurate and precise measurements of solar p-mode frequencies allow sensitive diagnostics of the adiabatic exponent Γ1 = (∂ln p/∂ln ρ)S as a function of depth in the adiabatically stratified part of the solar convective envelope. The profile of the adiabatic exponent contains information about the chemical composition of the …
Compound Twin Coronal Mass Ejections in the 2012 May 17 GLE Event
Chen, Y.; Wang, Yuming; Kong, X. +6 more
We report a multiple spacecraft observation of the 2012 May 17 GLE event. Using the coronagraph observations by SOHO/LASCO, STEREO-A/COR1, and STEREO-B/COR1, we identify two eruptions resulting in two coronal mass ejections (CMEs) that occurred in the same active region and close in time (~2 minutes) in the 2012 May 17 GLE event. Both CMEs were fa…
Determination of local plasma densities with the MARSIS radar: Asymmetries in the high−altitude Martian ionosphere
Fränz, M.; André, M.; Edberg, N. J. T. +6 more
We present a novel method for the automatic retrieval of local plasma density measurements from the Mars advanced radar for subsurface and ionospheric sounding (MARSIS) active ionospheric sounder (AIS) instrument. The resulting large data set is then used to study the configuration of the Martian ionosphere at altitudes above ∼300 km. An empirical…
Rehabilitating C IV-based black hole mass estimates in quasars
Shang, Zhaohui; Brotherton, M. S.; Runnoe, Jessie C. +1 more
Currently, the ability to produce black hole mass estimates using the C IV λ1549 line that are consistent with Hβ mass estimates is uncertain, due in large part to disagreement between velocity line width measurements for the two lines. This discrepancy between Hβ and C IV arises from the fact that both line profiles are treated the same way in si…
Mapping the Clumpy Structures within Submillimeter Galaxies Using Laser-Guide Star Adaptive Optics Spectroscopy
Smail, Ian; Swinbank, Mark; Chapman, Scott C. +4 more
We present the first integral-field spectroscopic observations of high-redshift submillimeter-selected galaxies (SMGs) using Laser-Guide Star Adaptive Optics. We target Hα emission of three SMGs at redshifts z ~ 1.4-2.4 with the OH-Suppressing Infrared Imaging Spectrograph on Keck. The spatially resolved spectroscopy of these galaxies reveals unre…
Weak lensing analysis of RXC J2248.7-4431
Zenteno, A.; Gruen, D.; Young, J. +8 more
We present a weak lensing analysis of the cluster of galaxies RXC J2248.7-4431, a massive system at z = 0.3475 with prominent strong lensing features covered by the Cluster Lensing And Supernova survey with Hubble (CLASH). Based on UBVRIZ imaging from the Wide-Field Imager camera at the MPG/ESO 2.2-m telescope, we measure photometric redshifts and…
Studying the properties of galaxy cluster morphology estimators
Böhringer, H.; Šuhada, R.; Ameglio, S. +1 more
X-ray observations of galaxy clusters reveal a large range of morphologies with various degrees of disturbance, showing that the assumptions of hydrostatic equilibrium and spherical shape, which are used to determine the cluster mass from X-ray data are not always satisfied. It is therefore important for the understanding of cluster properties as …
Radio Constraints on Heavily Obscured Star Formation within Dark Gamma-Ray Burst Host Galaxies
Perley, D. A.; Perley, R. A.
Highly dust-obscured starbursting galaxies (submillimeter galaxies and their ilk) represent the most extreme sites of star formation in the distant universe and contribute significantly to overall cosmic star formation beyond z > 1.5. Some stars formed in these environments may also explode as gamma-ray bursts (GRBs) and contribute to the popul…