281 research outputs found
Supernovae and their host galaxies - V. The vertical distribution of supernovae in disc galaxies
We present an analysis of the height distributions of the different types of
supernovae (SNe) from the plane of their host galaxies. We use a well-defined
sample of 102 nearby SNe appeared inside high-inclined (i > 85 deg),
morphologically non-disturbed S0-Sd host galaxies from the Sloan Digital Sky
Survey. For the first time, we show that in all the subsamples of spirals, the
vertical distribution of core-collapse (CC) SNe is about twice closer to the
plane of host disc than the distribution of SNe Ia. In Sb-Sc hosts, the
exponential scale height of CC SNe is consistent with those of the younger
stellar population in the Milky Way (MW) thin disc, while the scale height of
SNe Ia is consistent with those of the old population in the MW thick disc. We
show that the ratio of scale lengths to scale heights of the distribution of CC
SNe is consistent with those of the resolved young stars with ages from ~ 10
Myr up to ~ 100 Myr in nearby edge-on galaxies and the unresolved stellar
population of extragalactic thin discs. The corresponding ratio for SNe Ia is
consistent with the same ratios of the two populations of resolved stars with
ages from a few 100 Myr up to a few Gyr and from a few Gyr up to ~ 10 Gyr, as
well as with the unresolved population of the thick disc. These results can be
explained considering the age-scale height relation of the distribution of
stellar population and the mean age difference between Type Ia and CC SNe
progenitors.Comment: 11 pages, 6 figures, 6 tables, accepted for publication in MNRA
The impact of bars on the radial distribution of supernovae in disc galaxies
We present an analysis of the impact of bars on the radial distributions of
the different types of supernovae (SNe) in the stellar discs of host galaxies
with various morphologies. We find that in Sa-Sbc galaxies, the radial
distribution of core-collapse (CC) SNe in barred hosts is inconsistent with
that in unbarred ones, while the distributions of SNe Ia are not significantly
different. At the same time, the radial distributions of both types of SNe in
Sc-Sm galaxies are not affected by bars. We propose that the additional
mechanism shaping the distributions of Type Ia and CC SNe can be explained
within the framework of substantial suppression of massive star formation in
the radial range swept by strong bars, particularly in early-type spirals. The
radial distribution of CC SNe in unbarred Sa-Sbc galaxies is more centrally
peaked and inconsistent with that in unbarred Sc-Sm hosts, while the
distribution of SNe Ia in unbarred galaxies is not affected by host morphology.
These results can be explained by the distinct distributions of massive stars
in the discs of early-and late-type spirals.Comment: 3 pages, 1 figure. This is a brief summary of arXiv:1511.08896,
written for a short contribution in the EWASS-2016 Symposium 16 "Frontiers of
massive-star evolution and core-collapse supernovae
Delaminating Intramyocardial Hematoma in Patients with Heart Failure with Reduced Ejection Fraction: а Series of Clinical Cases
Delaminating intramyocardial hematoma (DIMH) is a rare and potentially life-threatening complication of acute myocardial infarction. Currently, only isolated reports of cases of myocardial dissection have been published, and until recently, the diagnosis of DIMH was carried out during autopsy or surgery. The article describes echocardiographic criteria and discusses some aspects of the therapy of this pathology. The description of clinical cases of noninvasive diagnosis of DIMH in men aged 60 and 62 years hospitalized with the clinic of decompensation of chronic heart failure is given. This complication in the presented patients was diagnosed using transthoracic echocardiography, thanks to which it was possible to identify the dissection of the myocardium, as well as to trace the dynamics of the organization of an intramyocardial hematoma into a parietal thrombus. Various approaches to patient management are demonstrated: conservative tactics allowed to successfully stabilize the course of chronic heart failure in the first patient, while the condition of the other required the transplantation of a donor heart a few months after discharge from the hospital
Electromagnetic field and radiation for a charge moving along a helical trajectory inside a waveguide with dielectric filling
We investigate the electromagnetic field generated by a point charge moving
along a helical trajectory inside a circular waveguide with conducting walls
filled by homogeneous dielectric. The parts corresponding to the radiation
field are separated and the formulae for the radiation intensity are derived
for both TE and TM waves. It is shown that the main part of the radiated quanta
is emitted in the form of the TE waves. Various limiting cases are considered.
The results of the numerical calculations show that the insertion of the
waveguide provides an additional mechanism for tuning the characteristics of
the emitted radiation by choosing the parameters of the waveguide and filling
medium.Comment: 17 pages, 9 figures, discussion, graphs, and references adde
- …