276 research outputs found
Progenitor's signatures in Type Ia supernova remnants
The remnants of Type Ia supernovae can provide important clues about their
progenitor-histories. We discuss two well-observed supernova remnants (SNRs)
that are believed to result from a Type Ia SN and use various tools to shed
light on the possible progenitor history. We find that Kepler's SNR is
consistent with a symbiotic binary progenitor consisted of a white dwarf and an
AGB star. Our hydrosimulations can reproduce the observed kinematic and
morphological properties. For Tycho's remnant we use the characteristics of the
X-ray spectrum and the kinematics to show that the ejecta has likely interacted
with dense circumstellar gas.Comment: 4 pages, 9 figures, proceedings for IAU Symposium 281, Padova, July
201
Parametric studies of cosmic ray acceleration in supernova remnants
We present a library of numerical models of cosmic-ray accelerating supernova
remnants (SNRs) evolving through a homogeneous ambient medium. We analyse
distributions of the different energy components and diffusive shock
acceleration time-scales for the models in various conditions. The library
comprises a variety of SNR evolutionary scenarios and is used to map remnants
with sufficiently known properties. This mapping constrains the respective
ambient medium properties and the acceleration efficiency. Employing the
library, we derive the ambient medium density, ambient magnetic field strength
and the cosmic-ray acceleration efficiency for models of Tycho and SN 1006
remnants and refine the ages of SNR 0509-67.5 and SNR 0519-69.0.Comment: 13 pages, 9 figures, MNRAS accepte
Inner-shell ionization, radiative losses and thermal conductivity in young SNRs
Self-consistent treatment of time-dependent ionization in hydrodynamical
calculations of the X-ray emission from young supernova remnants has been
performed. The novel feature of the calculations is that K_alpha lines from
species produced by inner-shell collisional ionization are included. Parameters
of the shocked ejecta are found from fitting the model spectrum to the observed
one. The application of the method to Tycho SNR using the classical
deflagration model W7 for the explosion enables us to well reproduce the
observed X-ray spectra and radial brightness profiles of the remnant.Comment: 4 pages, 3 figure, accepted for publication in MNRA
Modeling the interaction of thermonuclear supernova remnants with circumstellar structures: The case of Tycho's supernova remnant
The well-established Type Ia remnant of Tycho's supernova (SN 1572) reveals
discrepant ambient medium density estimates based on either the measured
dynamics or on the X-ray emission properties. This discrepancy can potentially
be solved by assuming that the supernova remnant (SNR) shock initially moved
through a stellar wind bubble, but is currently evolving in the uniform
interstellar medium with a relatively low density.
We investigate this scenario by combining hydrodynamical simulations of the
wind-loss phase and the supernova remnant evolution with a coupled X-ray
emission model, which includes non-equilibrium ionization. For the explosion
models we use the well-known W7 deflagration model and the delayed detonation
model that was previously shown to provide good fits to the X-ray emission of
Tycho's SNR.
Our simulations confirm that a uniform ambient density cannot simultaneously
reproduce the dynamical and X-ray emission properties of Tycho. In contrast,
models that considered that the remnant was evolving in a dense, but small,
wind bubble reproduce reasonably well both the measured X-ray emission spectrum
and the expansion parameter of Tycho's SNR. Finally, we discuss possible mass
loss scenarios in the context of single- and double-degenerate models which
possible could form such a small dense wind bubble.Comment: 12 pages, 7 figures, accepted for publication in MNRA
Cold diffuse interstellar medium of Magellanic Clouds: I. HD molecule and cosmic-ray ionization rate
HD molecule is one the most abundant molecule in the Universe and due to its
sensibility to the conditions in the medium, it can be used to constrain
physical parameters in the medium where HD resides. Lately we have shown that
HD abundance can be enhanced in the low metallicity medium. Large and Small
Magellanic Clouds give us an opportunity to study low metallicity galaxies in
details towards different sightlines due to their proximity to our Galaxy. We
revisited FUSE space telescope archival spectra towards bright stars in
Magellanic Clouds to search for HD molecules, associated with the medium of
these galaxies. We reanalysed H absorption lines and constrained HD column
density at the positions of H components. We detected HD towards 24
sightlines (including 19 new detections). We try to measure cosmic ray
ionization rate for several systems using measured ,
and in most cases get loose constraints due to insufficient quality of the FUSE
spectra.Comment: accepted for publication in MNRA
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