156 research outputs found
Update on the ESA-CAS Joint Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) Mission
The SMILE (Solar wind Magnetosphere Ionosphere Link Explorer) mission aims at deepening our understanding of the interaction of the solar wind with the Earth magnetosphere. It is the first time that ESA and CAS jointly select, design, implement, launch, and operate a space mission. The mission was adopted by CAS in November 2016 and by ESA in March 2019 with a target launch date by the end of 2023
General Relativistic Radiative Transfer: Applications to Black-Hole Systems
We present general relativistic radiation transfer formulations which include opacity effects due to absorption, emission and scattering explicitly. We consider a moment expansions for the transfer in the presence of scattering. The formulation is applied to calculation emissions from accretion and outflows in black-hole systems. Cases with thin accretion disks and accretion tori are considered. Effects, such as emission anisotropy, non-stationary flows and geometrical self-occultation are investigated. Polarisation transfer in curved space-time is discussed qualitatively
Comparative Analysis and Variability of the Jovian X‐Ray Spectra Detected by the Chandra and XMM‐Newton Observatories
Expanding upon recent work, a more comprehensive spectral model based on charge exchange induced X‐ray emission by ions precipitating into the Jovian atmosphere is used to provide new understanding of the polar auroras. In conjunction with the Xspec spectral fitting software, the model is applied to analyze observations from both Chandra and XMM‐Newton by systematically varying the initial precipitating ion parameters to obtain the best fit model for the observed spectra. In addition to the oxygen and sulfur ions considered previously, carbon is included to discriminate between solar wind and Jovian magnetospheric ion origins, enabled by the use of extensive databases of both atomic collision cross sections and radiative transitions. On the basis of fits to all the Chandra observations, we find that carbon contributes negligibly to the observed polar X‐ray emission suggesting that the highly accelerated precipitating ions are of magnetospheric origin. Most of the XMM‐Newton fits also favor this conclusion with one exception that implies a possible carbon contribution. Comparison among all the spectra from these two observatories in light of the inferred initial energies and relative abundances of precipitating ions from the modeling show that they are significantly variable in time (observation date) and space (north and south polar X‐ray auroras).Astronom
Simulation of the SMILE Soft X-ray Imager response to a southward interplanetary magnetic field turning
The Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) Soft X-ray Imager (SXI) will shine a spotlight on magnetopause dynamics during magnetic reconnection. We simulate an event with a southward interplanetary magnetic field turning and produce SXI count maps with a 5-minute integration time. By making assumptions about the magnetopause shape, we find the magnetopause standoff distance from the count maps and compare it with the one obtained directly from the magnetohydrodynamic (MHD) simulation. The root mean square deviations between the reconstructed and MHD standoff distances do not exceed 0.2 RE (Earth radius) and the maximal difference equals 0.24 RE during the 25-minute interval around the southward turning
Accretion and outflow of gas in Markarian 509
A major uncertainty in models for photoionised outflows in AGN is the
distance of the gas to the central black hole. We present the results of a
massive multiwavelength monitoring campaign on the bright Seyfert 1 galaxy Mrk
509 to constrain the location of the outflow components dominating the soft
X-ray band.
Mrk 509 was monitored by XMM-Newton, Integral, Chandra, HST/COS and Swift in
2009. We have studied the response of the photoionised gas to the changes in
the ionising flux produced by the central regions. We were able to put tight
constraints on the variability of the absorbers from day to year time scales.
This allowed us to develop a model for the time-dependent photoionisation in
this source.
We find that the more highly ionised gas producing most X-ray line opacity is
at least 5 pc away from the core; upper limits to the distance of various
absorbing components range between 20 pc up to a few kpc. The more lowly
ionised gas producing most UV line opacity is at least 100 pc away from the
nucleus.
These results point to an origin of the dominant, slow (v<1000 km/s) outflow
components in the NLR or torus-region of Mrk 509. We find that while the
kinetic luminosity of the outflow is small, the mass carried away is likely
larger than the 0.5 Solar mass per year accreting onto the black hole.
We also determined the chemical composition of the outflow as well as
valuable constraints on the different emission regions. We find for instance
that the resolved component of the Fe-K line originates from a region 40-1000
gravitational radii from the black hole, and that the soft excess is produced
by Comptonisation in a warm (0.2-1 keV), optically thick (tau~10-20) corona
near the inner part of the disk.Comment: 4 pages, 1 figure, Proceedings of IAUS 290 "Feeding Compact Objects:
Accretion on All Scales", C. M. Zhang, T. Belloni, M. Mendez & S. N. Zhang
(eds.
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