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Deep Hubble Space Telescope Imaging in NGC 6397: Stellar Dynamics
Anderson, J.; Rich, R. M.; Dotter, A. +9 more
Multi-epoch observations with the Advanced Camera for Surveys on the Hubble Space Telescope provide a unique and comprehensive probe of stellar dynamics within NGC 6397. We are able to confront analytic models of the globular cluster with the observed stellar proper motions. The measured proper motions probe well along the main sequence from 0.8 t…
Hubble Space Telescope Narrowband Search for Extended Lyα Emission around Two z > 6 Quasars
Hennawi, Joseph F.; Strauss, Michael A.; Rix, Hans-Walter +8 more
We search for extended Lyα emission around two z > 6 quasars, SDSS J1030+0524 (z = 6.309) and SDSS J1148+5251 (z = 6.419) using Wide Field Camera 3 narrowband filters on board the Hubble Space Telescope. For each quasar, we collected two deep, narrowband images, one sampling the Lyα line+continuum at the quasar redshifts and one of the continuu…
First detection of O2 1.27 µm nightglow emission at Mars with OMEGA/MEX and comparison with general circulation model predictions
Gondet, B.; Montmessin, F.; Bertaux, J. L. +2 more
We report the first detection in the atmosphere of Mars of the nightside O2(a1Δg) emission at 1.27 µm from limb observations of the OMEGA imaging spectrometer on board Mars Express (MEX). The emission, detected in three cases out of 40 observations, is due to recombination in a downwelling air parcel of O ato…
The onset of high-mass star formation in the direct vicinity of the Galactic mini-starburst W43
Henning, Th.; Krause, O.; Beuther, H. +10 more
Context. The earliest stages of high-mass star formation are still poorly characterized. Densities, temperatures and kinematics are crucial parameters for simulations of high-mass star formation. It is also unknown whether the initial conditions vary with environment.
Aims: We want to investigate the youngest massive gas clumps in the environ…
Detectability of low-energy X-ray spectral components in type 1 active galactic nuclei
Mateos, S.; Stewart, G. C.; Scott, A. E.
In this paper we examine the percentage of type 1 active galactic nuclei (AGN) which require the inclusion of a soft excess component and/or significant cold absorption in the modelling of their X-ray spectra obtained by XMM-Newton. We do this by simulating spectra which mimic typical spectral shapes in order to find the maximum detectability expe…
Fast X-ray transients towards the Galactic bulge with the Rossi X-ray Timing Explorer
Negueruela, I.; Swank, J. H.; Markwardt, C. B. +1 more
In X-ray binaries, rapid variability in X-ray flux of greater than an order of magnitude on time-scales of a day or less appears to be a signature of wind accretion from a supergiant companion. When the variability takes the form of rare, brief, bright outbursts with only faint emission between them, the systems are called supergiant fast X-ray tr…
Spatially Dependent Heating and Ionization in an ICME Observed by Both ACE and Ulysses
Laming, J. Martin; von Steiger, Rudolf; Rakowski, Cara E. +1 more
The 2005 January 21 interplanetary coronal mass ejection (ICME) observed by multiple spacecraft at L1 was also observed from January 21-February 4 at Ulysses (5.3 AU). Previous studies of this ICME have found evidence suggesting that the flanks of a magnetic cloud like structure associated with this ICME were observed at L1 while a more central cu…
Double mid-latitude dynamical reconnection at the magnetopause: An efficient mechanism allowing solar wind to enter the Earth's magnetosphere
Califano, F.; Pegoraro, F.; Faganello, M. +1 more
Three-dimensional simulations of the Kelvin-Helmholtz (KH) instability in a magnetic configuration reproducing typical conditions at the flank Earth's magnetosphere during northward periods show the system's ability to generate favorable conditions for magnetic reconnection to occur at mid-latitude. Once these conditions are established, magnetic …
On the Variations of Fundamental Constants and Active Galactic Nucleus Feedback in the Quasi-stellar Object Host Galaxy RXJ0911.4+0551 at z = 2.79
Menten, K. M.; Walter, F.; Henkel, C. +4 more
We report on sensitive observations of the CO(J = 7→6) and C I(3 P 2 → 3 P 1) transitions in the z = 2.79 QSO host galaxy RXJ0911.4+0551 using the IRAM Plateau de Bure interferometer. Our extremely high signal-to-noise spectra combined with the narrow CO line width of this source (FWHM = 120 km s-1<…
Spectral and timing properties of the accreting X-ray millisecond pulsar IGR J17498-2921
Stella, L.; Bozzo, E.; Kuiper, L. +5 more
Context. IGR J17498-2921 is the third X-ray transient accreting millisecond pulsar discovered by INTEGRAL. It was in outburst for about 40 days beginning on August 08, 2011.
Aims: We analyze the spectral and timing properties of the object and the characteristics of X-ray bursts to constrain the physical processes responsible for the X-ray pr…