Search Publications
Using SDO's AIA to investigate energy transport from a flare's energy release site to the chromosphere
Brosius, J. W.; Holman, G. D.
Context. Coordinated observations of a GOES B4.8 microflare with SDO's Atmospheric Imaging Assembly (AIA) and the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) on 2010 July 31 show that emission in all seven of AIA's EUV channels brightened simultaneously nearly 6 min before RHESSI or GOES detected emission from plasma at temperatures aro…
X-Ray Binaries in the Ultrahigh Encounter Rate Globular Cluster NGC 6388
Heinke, Craig O.; Bailyn, Charles D.; Cohn, Haldan N. +5 more
We report the results of a joint Chandra Hubble Space Telescope study of the X-ray binary (XRB) population in the massive, high-density globular cluster NGC 6388. NGC 6388 has one of the highest predicted XRB production rates of any Galactic cluster. We detected a large population of 61 Chandra sources within the half-mass radius with LX
Residual cooling and persistent star formation amid active galactic nucleus feedback in Abell 2597
Fabian, A. C.; Combes, F.; Salomé, P. +18 more
New Chandra X-ray and Herschel Far-Infrared (FIR) observations enable a multiwavelength study of active galactic nucleus (AGN) heating and intracluster medium (ICM) cooling in the brightest cluster galaxy (BCG) of Abell 2597 (z= 0.0821). The new Chandra observations reveal the central ≲30 kpc X-ray cavity network to be more extensive than previous…
Hydrogen density in the dayside venusian exosphere derived from Lyman-α observations by SPICAV on Venus Express
Bertaux, J. -L.; Chaufray, J. -Y.; Leblanc, F. +2 more
A series of observations of the venusian hydrogen corona made by SPICAV on Venus Express are analyzed to estimate the amount of hydrogen in the exosphere of Venus. These observations were made between November 2006 and July 2007 at altitudes from 1000 km to 8000 km on the dayside. The Lyman-α brightness profiles derived are reproduced by the sum o…
Multiscale Dynamics of Solar Magnetic Structures
Davila, Joseph M.; Uritsky, Vadim M.
Multiscale topological complexity of the solar magnetic field is among the primary factors controlling energy release in the corona, including associated processes in the photospheric and chromospheric boundaries. We present a new approach for analyzing multiscale behavior of the photospheric magnetic flux underlying these dynamics as depicted by …
Underestimates of magnetic flux in coupled MHD model solar wind solutions
Riley, Pete; Stevens, Michael L.; Linker, Jon A. +1 more
When validated with spacecraft observations, one enduring characteristic of global MHD solar wind models is the tendency to underestimate the interplanetary magnetic flux. This study quantifies the “missing flux” problem for models used in the coordinated Center for Integrated Space Weather Modeling study of corotating interaction regions, and ide…
Thin current sheets in the presence of a guiding magnetic field in Earth's magnetosphere
Malova, H. V.; Delcourt, D. C.; Petrukovich, A. A. +7 more
A self-consistent theory of relatively thin anisotropic current sheets (TCS) in collisionless plasma is developed, taking into account the presence of a guiding field By (all notations are used in the GSM coordinate system). TCS configurations with a finite value of guiding field By are often observed in Earth's magnetotail a…
Evolution of the spectral curvature in the ultraluminous X-ray source Holmberg II X-1
Kaaret, P.; Farrell, S. A.; Poutanen, J. +2 more
Ultraluminous X-ray sources (ULXs) are interesting systems as they can host intermediate-mass black holes. Alternatively, ULXs can represent stellar mass black holes accreting at super-Eddington rates. Recently, spectral curvature or breaks at energies above a few keV have been detected in high-quality ULX spectra. These spectral features have bee…
Modeling the physical and excitation conditions of the molecular envelope of NGC 7027
Alcolea, J.; Santander-García, M.; Bujarrabal, V.
Context. The link between the shaping of bipolar planetary nebulae and the mass ejection activity of their central stars is still poorly understood. Appropriately characterizing the evolution of shells ejected during the late stages of stellar evolution and the interaction between these shells is fundamental to gain insight into the mechanism of n…
The luminosity function and stellar mass-to-light ratio of the massive globular cluster NGC 2419
Dalessandro, E.; Bellazzini, M.; Ibata, R. +1 more
We used archival Hubble Space Telescope Wide Field Camera 3 (WFC3) images to obtain the luminosity function of the remote globular cluster NGC 2419 from 2 mag above the horizontal branch level down to ≃ 3.0 mag below the turn-off point (to MI≃ 6.4), approximately covering the range of initial stellar masses ?. The completeness-corrected…