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Multiwavelength analysis of the Lyman-α emitting galaxy Haro 2: relation between the diffuse Lyman-α and soft X-ray emissions
Schaerer, D.; Östlin, G.; Hayes, M. +5 more
Context. Lyman-α emission is commonly used as star formation tracer in cosmological studies. Nevertheless, resonant scattering strongly affects the resulting luminosity, leading to variable and unpredictable escape fractions in different objects.
Aims: To understand how the Lyα escape fraction depends on the properties of the star-forming reg…
Clear Detection of Chromospheric Evaporation Upflows with High Spatial/Temporal Resolution by Hinode XRT
Yamamoto, T. T.; Imada, S.; Nitta, S.
We find clear evidence for typical chromospheric evaporation associated with small transient brightenings, using the data from the X-ray Telescope (XRT) onboard Hinode. We found 13 events, each having a pair of evaporation upflows arising almost symmetrically from both foot points of a magnetic loop. These facts strongly support the standard flare…
Ultraviolet Spectroscopy of Rapidly Rotating Solar-Mass Stars: Emission-line Redshifts as a Test of the Solar-Stellar Connection
France, Kevin; Linsky, Jeffrey L.; Ayres, Tom +1 more
We compare high-resolution ultraviolet spectra of the Sun and thirteen solar-mass main-sequence stars with different rotational periods that serve as proxies for their different ages and magnetic field structures. In this, the second paper in the series, we study the dependence of ultraviolet emission-line centroid velocities on stellar rotation p…
Entropy Generation across Earth's Collisionless Bow Shock
Dandouras, I.; Cao, J. B.; Parks, G. K. +9 more
Earth’s bow shock is a collisionless shock wave but entropy has never been directly measured across it. The plasma experiments on Cluster and Double Star measure 3D plasma distributions upstream and downstream of the bow shock allowing calculation of Boltzmann’s entropy function H and his famous H theorem, dH/dt≤0. The collisionless Boltzmann (Vla…
Flows at the Edge of an Active Region: Observation and Interpretation
Vial, J. -C.; Régnier, S.; Buchlin, E. +1 more
Upflows observed at the edges of active regions have been proposed as the source of the slow solar wind. In the particular case of Active Region (AR) 10942, where such an upflow has been already observed, we want to evaluate the part of this upflow that actually remains confined in the magnetic loops that connect AR 10942 to AR 10943. Both active …
The continued spectral and temporal evolution of RX J0720.4-3125
Haberl, F.; de Vries, C. P.; Vink, J. +4 more
RX J0720.4-3125 is the most peculiar object among a group of seven isolated X-ray pulsars (the so-called Magnificent Seven), since it shows long-term variations of its spectral and temporal properties on time-scales of years. This behaviour was explained by different authors either by free precession (with a 7 or 14 yr period) or possibly a glitch…
A phenomenological model for the X-ray spectrum of nova V2491 Cygni
Kaastra, J. S.; Costantini, E.; Ness, J. -U. +3 more
The X-ray flux of nova V2491 Cyg reached a maximum some forty days after optical maximum. The X-ray spectrum at that time, obtained with the RGS of XMM-Newton, shows deep, blue-shifted absorption by ions of a wide range of ionization. We show that the deep absorption lines of the X-ray spectrum at maximum, and those observed nine days later, are w…
Magnetic flux rope formation within a magnetosheath hot flow anomaly
Zhang, H.; Zong, Q. -G.; Lavraud, B. +4 more
We report observations on 1 March 2004 by the Cluster spacecraft of a hot flow anomaly (HFA) encountered in the dayside magnetosheath near Earth's bow shock. Embedded within the HFA was a magnetic flux rope with a diameter of a few thousand km, which was moving sunward and was presumably expanding. The pristine upstream solar wind seen by the ACE …
Two-phase ICM in the Central Region of the Rich Cluster of Galaxies A1795: A Joint Chandra, XMM-Newton, and Suzaku View
Makishima, Kazuo; Nakazawa, Kazuhiro; Xu, Haiguang +7 more
Based on a detailed analysis of the high-quality Chandra, XMM-Newton, and Suzaku data of the X-ray bright cluster of galaxies A1795, we report clear evidence for a two-phase intracluster medium (ICM) structure, which consists of a cool (with a temperature T c ≈ 2.0-2.2 keV) and a hot (T h ≈ 5.0-5.7 keV) component that coexist…
Two-dimensional kinematics of SLACS lenses - IV. The complete VLT-VIMOS data set
Treu, Tommaso; Czoske, Oliver; Koopmans, Léon V. E. +2 more
This paper presents the full Very Large Telescope (VLT)/VIMOS-IFU data set and related data products from an ESO Large Programme with the observational goal of obtaining two-dimensional kinematic data of early-type lens galaxies, out to one effective radius. The sample consists of 17 early-type galaxies (ETGs) selected from the SLACS gravitational…