Search Publications
Constraints on Coronal Mass Ejection Evolution from in Situ Observations of Ionic Charge States
Antiochos, Spiro K.; Zurbuchen, Thomas H.; Gruesbeck, Jacob R. +1 more
We present a novel procedure for deriving the physical properties of coronal mass ejections (CMEs) in the corona. Our methodology uses in situ measurements of ionic charge states of C, O, Si, and Fe in the heliosphere and interprets them in the context of a model for the early evolution of interplanetary CME (ICME) plasma, between 2 and 5 R s…
Multi-wavelength observations of Proxima Centauri
Liefke, C.; Schmitt, J. H. M. M.; Reiners, A. +5 more
Aims: We report simultaneous observations of the nearby flare star Proxima Centauri with VLT/UVES and XMM-Newton over three nights in March 2009. Our optical and X-ray observations cover the star's quiescent state, as well as its flaring activity and allow us to probe the stellar atmospheric conditions from the photosphere into the chromosphe…
Dayside ionosphere of Mars: Empirical model based on data from the MARSIS instrument
Gurnett, D. A.; Němec, F.; Morgan, D. D. +2 more
We present results of a systematic study of electron densities in the dayside Martian ionosphere measured by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board the Mars Express spacecraft. There are two distinct regions controlled by different physical mechanisms. The first region is located at altitudes up…
LYRA Observations of Two Oscillation Modes in a Single Flare
Berghmans, D.; Goossens, M.; Zender, J. +2 more
We analyze light curves from the LYRA irradiance experiment on board PROBA2 during the flare of 2010 February 8. We see both long- and short-period oscillations during the flare. The long-period oscillation is interpreted in terms of standing slow sausage modes; the short-period oscillation is thought to be a standing fast sausage mode. The simult…
A Deep Chandra ACIS Study of NGC 4151. III. The Line Emission and Spectral Analysis of the Ionization Cone
Elvis, Martin; Zezas, Andreas; Schinnerer, Eva +6 more
This paper is the third in a series in which we present deep Chandra ACIS-S imaging spectroscopy of the Seyfert 1 galaxy NGC 4151, devoted to study its complex circumnuclear X-ray emission. Emission features in the soft X-ray spectrum of the bright extended emission (L 0.3-2 keV ~ 1040 erg s-1) at r > 130 pc (2'…
The Variable Quiescent X-Ray Emission of the Transient Neutron Star XTE J1701-462
Homan, Jeroen; Cackett, Edward M.; Fridriksson, Joel K. +6 more
We present the results of continued monitoring of the quiescent neutron star low-mass X-ray binary XTE J1701-462 with Chandra and Swift. A new Chandra observation from 2010 October extends our tracking of the neutron star surface temperature from ≃ 800 days to ≃ 1160 days since the end of an exceptionally luminous 19 month outburst. This observati…
Morphological Evolution of Galaxies from Ultra-deep Hubble Space Telescope Wide Field Camera 3 Imaging: The Hubble Sequence at z ~ 2
van Dokkum, Pieter G.; Franx, Marijn; Illingworth, Garth D. +4 more
We use ultra-deep Hubble Space Telescope Wide Field Camera 3/infrared imaging of the Hubble Ultra Deep Field to investigate the rest-frame optical morphologies of a mass-selected sample of galaxies at z ~ 2. We find a large variety of galaxy morphologies, ranging from large, blue, disk-like galaxies to compact, red, early-type galaxies. We derive …
Herschel-ATLAS: the link between accretion luminosity and star formation in quasar host galaxies
Rodighiero, G.; Ivison, R. J.; de Zotti, G. +28 more
We use the science demonstration field data of the Herschel Astrophysical Terahertz Large Area Survey to study how star formation, traced by the far-infrared Herschel data, is related to both the accretion luminosity and redshift of quasars selected from the Sloan Digital Sky Survey (SDSS) and the 2dF-SDSS luminous red galaxy (LRG) and Quasar Spec…
Emission Measure Distribution and Heating of Two Active Region Cores
Tripathi, Durgesh; Mason, Helen E.; Klimchuk, James A.
Using data from the Extreme-ultraviolet Imaging Spectrometer aboard Hinode, we have studied the coronal plasma in the core of two active regions. Concentrating on the area between opposite polarity moss, we found emission measure distributions having an approximate power-law form EMvpropT 2.4 from log T = 5.5 up to a peak at log T = 6.5…
Compact molecular disc and ionized gas outflows within 350 pc of the active nucleus of Mrk 1066
Storchi-Bergmann, Thaisa; Riffel, Rogemar A.
We present stellar and gaseous kinematics of the inner ≈350-pc radius of the Seyfert galaxy Mrk 1066 derived from J and Kl bands data obtained with the Gemini's Near-Infrared Integral Field Spectrograph (NIFS) at a spatial resolution of ≈35 pc. The stellar velocity field is dominated by rotation in the galaxy plane but shows an S-shape …