Search Publications
The Smooth Cyclotron Line in Her X-1 as Seen with Nuclear Spectroscopic Telescope Array
Hailey, Charles J.; Fürst, Felix; Klochkov, Dmitry +17 more
Her X-1, one of the brightest and best studied X-ray binaries, shows a cyclotron resonant scattering feature (CRSF) near 37 keV. This makes it an ideal target for a detailed study with the Nuclear Spectroscopic Telescope Array (NuSTAR), taking advantage of its excellent hard X-ray spectral resolution. We observed Her X-1 three times, coordinated w…
A Detailed X-Ray Investigation of ζ Puppis. II. The Variability on Short and Long Timescales
Nazé, Yaël; Gosset, Eric; Oskinova, Lidia M.
Stellar winds are a crucial component of massive stars, but their exact properties still remain uncertain. To shed some light on this subject, we have analyzed an exceptional set of X-ray observations of ζ Puppis, one of the closest and brightest massive stars. The sensitive light curves that were derived reveal two major results. On the one hand,…
Solar Magnetic Activity Cycles, Coronal Potential Field Models and Eruption Rates
Petrie, G. J. D.
We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated potential-field models based on longitudinal full-disk photospheric magnetograms from the National Solar Observatory…
Complete Infrared Spectral Energy Distributions of Millimeter Detected Quasars at z > 5
Meisenheimer, K.; Walter, F.; Krause, O. +7 more
We present Herschel far-infrared (FIR) photometry of 11 quasars at redshift z > 5 that have previously been detected at 1.2 mm. We perform full spectral energy distribution (SED) fits over the wavelength range λrest ~ 0.1-400 µm for those objects with good Herschel detections. These fits reveal the need for an additional FIR co…
Magnetic Energy Partition between the Coronal Mass Ejection and Flare from AR 11283
Feng, L.; Inhester, B.; Gan, W. Q. +4 more
On 2011 September 6, an X-class flare and a halo coronal mass ejection (CME) were observed from Earth erupting from the same active region AR 11283. The magnetic energy partition between them has been investigated. SDO/HMI vector magnetograms were used to obtain the coronal magnetic field using the nonlinear force-free field (NLFFF) extrapolation …
Water Absorption in Galactic Translucent Clouds: Conditions and History of the Gas Derived from Herschel/HIFI PRISMAS Observations
Godard, B.; Lis, D. C.; Phillips, T. G. +8 more
We present Herschel/HIFI observations of the three ground state transitions of H2O (556, 1669, and 1113 GHz) and H218O (547, 1655, and 1101 GHz)—as well as the first few excited transitions of H2O (987, 752, and 1661 GHz)—toward six high-mass star-forming regions, obtained as part of the PRISMAS (PRobing…
The Radial Distribution of Star Formation in Galaxies at z ~ 1 from the 3D-HST Survey
Schmidt, Kasper B.; van Dokkum, Pieter G.; Franx, Marijn +16 more
The assembly of galaxies can be described by the distribution of their star formation as a function of cosmic time. Thanks to the WFC3 grism on the Hubble Space Telescope (HST) it is now possible to measure this beyond the local Universe. Here we present the spatial distribution of Hα emission for a sample of 54 strongly star-forming galaxies at z…
The "Twin-CME" Scenario and Large Solar Energetic Particle Events in Solar Cycle 23
Li, Gang; Zhao, Lulu; Ding, Liuguan +1 more
Energetic particles in large solar energetic particle (SEP) events are a major concern for space weather. Recently, Li et al. proposed a "twin-CME" scenario for ground-level events. Here we extend that study to large SEP events in solar cycle 23. Depending on whether preceding coronal mass ejections (CMEs) within 9 hr exist and whether ions >10…
X-Ray Selected AGN Host Galaxies are Similar to Inactive Galaxies out to z = 3: Results from CANDELS/CDF-S
Wuyts, S.; Giavalisco, M.; Dunlop, J. S. +18 more
We use multi-band spatially resolved photometry from the Cosmic Assembly Near-IR Deep Legacy Survey in the 4 Ms Chandra Deep Field-South to explore the nuclear and extended colors, color gradients, and stellar populations of the host galaxies of X-ray selected active galactic nuclei (AGNs) out to z = 3. Based on a study of their central light, we …
Inner Heliospheric Evolution of a "Stealth" CME Derived from Multi-view Imaging and Multipoint in Situ observations. I. Propagation to 1 AU
Jian, L. K.; Szabo, A.; Nieves-Chinchilla, T. +4 more
Coronal mass ejections (CMEs) are the main driver of space weather. Therefore, a precise forecasting of their likely geo-effectiveness relies on an accurate tracking of their morphological and kinematical evolution throughout the interplanetary medium. However, single viewpoint observations require many assumptions to model the development of the …