892 research outputs found
Multi-component parametric inversion of galaxy kinematics and stellar populations using full spectral fitting
The stellar line-of-sight velocity distribution (LOSVD) can be strongly
asymmetric in regions where the light contributions of both disc and bulge in
spiral and lenticular galaxies are comparable. Existing techniques for the
stellar kinematics analysis do not take into account the difference of disc and
bulge stellar populations. Here we present a novel approach to the analysis of
stellar kinematics and stellar populations. We use a two-component model of
spectra where different stellar population components are convolved with pure
Gaussian LOSVDs. For this model we present Monte-Carlo simulations
demonstrating degeneracies between the parameters.Comment: 3 pages, 2 figures; to appear in the proceedings of "The Spectral
Energy Distribution of Galaxies", Preston, UK, 5-9 September 201
NBursts+phot: parametric recovery of galaxy star formation histories from the simultaneous fitting of spectra and broad-band spectral energy distributions
We present NBursts+phot, a novel technique for the parametric inversion of
spectrophotometric data for unresolved stellar populations where
high-resolution spectra and broadband SEDs are fitted simultaneously helping to
break the degeneracies between parameters of multi-component stellar population
models.Comment: 3 pages, 1 figure, proceedings of the IAU Symposium 28
Color Transformations of Photometric Measurements of Galaxies in Optical and Near-Infrared Wide-Field Imaging Surveys
Over the past 2 decades, wide-field photometric surveys in optical and
infrared domains reached a nearly all-sky coverage thanks to numerous
observational facilities operating in both hemispheres. However, subtle
differences among exact realizations of Johnson and SDSS photometric systems
require one to convert photometric measurements into the same system prior to
analysis of composite datasets originating from multiple surveys. It turns out
that the published photometric transformations lead to substantial biases when
applied to integrated photometry of galaxies from the corresponding catalogs.
Here we present photometric transformations based on piece-wise linear
approximations of integrated photometry of galaxies in the optical surveys
SDSS, DECaLS, BASS, MzLS, DES, DELVE, KiDS, VST ATLAS, and the near-infrared
surveys UKIDSS, UHS, VHS, and VIKING. We validate our transformations by
constructing k-corrected color-magnitude diagrams of non-active galaxies and
measuring the position and tightness of the "red sequence". We also provide
transformations for aperture magnitudes and show how they are affected by the
image quality difference among the surveys. We present the implementation of
the derived transformations in Python and IDL and also a web-based color
transformation calculator for galaxies. By comparing DECaLS and DES, we
identified systematic issues in DECaLS photometry for extended galaxies, which
we attribute to the photometric software package used by DECaLS. As an
application of our method, we compiled two multi-wavelength photometric
catalogs for over 200,000 low- and intermediate-redshift galaxies originating
from CfA FAST and Hectospec spectral archives.Comment: 24 pages, 21 figures, accepted for publication in PASP. The "Color
transformations" web service and the Python and IDL codes are available at
https://colors.voxastro.org
Digital Technologies in Providing Development of Algorithms Surgical Treatment of Supraventricular Arrhythmias
The aim of the study was the development and clinical application of patient selection algorithm for surgical treatment of longlasting persistent atrial fibrillation. The study included 235 patients with acquired heart disease and coronary artery disease, which in the period from 1999 to 2015 performed surgical treatment of long-term persistent atrial fibrillation (RF “MAZE III” procedure) in conjunction with the correction of the underlying heart disease. The patients were divided into 2 groups according to the method of operation: the group 1 – 135 patients (76 women and 59 men) who have applied an integrated approach to surgery for atrial fibrillation, including penetrating method of RF effects on atrial myocardium and the study of the function of the sinus node before and after the operation (these patients were operated on from 2008 to 2015). The group 2 – 100 patients (62 women and 38 men) with a “classical” method of monopolar RF “MAZE III”, which the sinus node function was not studied. We used the combined (epi- and endocardial) method of RF "MAZE". This algorithm is decreasing of possible permanent pacemaker postoperatively. The initial sinus node function in these patients, measured using the original method, the basic line of this algorithm was taken. The results showed that use this algorithm for selection of patients allows significantly reduce the possibility of pacemaker implantation in the postoperative perio
Performance studies of the final prototype for the CASTOR forward calorimeter at the CMS experiment
We present performance results of the final prototype for the CASTOR quartz-tungsten sampling calorimeter, to be installed in the very forward region of the CMS experiment at the LHC. The energy linearity and resolution, the uniformity, as well as the spatial resolution of the prototype to electromagnetic and hadronic showers are studied with 10--200 GeV electrons, 20--350 GeV pions, and 50, 150 GeV muons in beam tests carried out at CERN/SPS in 2007
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