28 research outputs found
SN 2008fv: the third type Ia supernova in NGC 3147
Multiple outbursts of type Ia SNe in one galaxy present a unique opportunity
to study the homogeneity of these objects. NGC 3147 is only the second known
galaxy with three SNe Ia, another one is NGC 1316. We present CCD UBVRI
photometry for SN Ia 2008fv and compare the light and color curves of this
object with those for SNe Ia discovered earlier in NGC 3147: 1972H and 1997bq.
The photometric properties of SNe 1997bq and 2008fv are nearly identical, while
SN 1972H exhibits faster declining light curve.Comment: 11 pages, 6 figures, submitted to Peremennye Zvezdy (Variable Stars
Apophis planetary defense campaign
We describe results of a planetary defense exercise conducted during the close approach to Earth by the near-Earth asteroid (99942) Apophis during 2020 December–2021 March. The planetary defense community has been conducting observational campaigns since 2017 to test the operational readiness of the global planetary defense capabilities. These community-led global exercises were carried out with the support of NASA's Planetary Defense Coordination Office and the International Asteroid Warning Network. The Apophis campaign is the third in our series of planetary defense exercises. The goal of this campaign was to recover, track, and characterize Apophis as a potential impactor to exercise the planetary defense system including observations, hypothetical risk assessment and risk prediction, and hazard communication. Based on the campaign results, we present lessons learned about our ability to observe and model a potential impactor. Data products derived from astrometric observations were available for inclusion in our risk assessment model almost immediately, allowing real-time updates to the impact probability calculation and possible impact locations. An early NEOWISE diameter measurement provided a significant improvement in the uncertainty on the range of hypothetical impact outcomes. The availability of different characterization methods such as photometry, spectroscopy, and radar provided robustness to our ability to assess the potential impact risk
Testing of Adaptive Symplectic Conservative Numerical Methods for Solving the Kepler Problem
Effective planning of observations of space objects on different types of orbits
Abstract:
In this paper we review the concept of prospective software package for the automated planning of observations for an optical telescope network. Special attention to issues of more effective planning survey and combined observations of artificial space objects on different types of orbits.Note:
Research direction:Mathematical modelling in actual problems of science and technic
Ison network tracking of space debris: current status and achievements
Interagency International Scientific Optical Network (ISON) represents one of largest systems specializing in observation of space objects. ISON provides permanent monitoring of the whole GEO region, regular surveying of Molniya type orbits, and tracking of objects at GEO, GTO, HEO and LEO. Currently ISON cooperates with 43 observation facilities of various affiliations with 100 telescopes in 17 countries. Six telescope subsets have been completed to the date, ISON encompasses five groups of telescopes and three scheduling centers. Obtained measurements are processed at the KIAM ballistic center to be used for scientific and applied goals, including collision risks analysis and space situation analysis. 20 millions measurements in 2.58 millions of tracklets for more 6740 objects have been collected by KIAM in 2016
Gamma-ray burst observations with ISON network
We present details of the ISON network for GRB follow-up and complete list of observations in 2010–2012
Oral single high-dose aspirin results in a long-lived inhibition of anodal current-induced vasodilatation
1. Acetyl salicyclic acid (aspirin) irreversibly blocks cyclo-oxygenase (COX). This effect is short-lived in endothelial or smooth muscle cells due to resynthesis but long-lived in platelets devoid of synthesis ability. Aspirin blocks the anodal current-induced vasodilatation, suggesting participation by prostaglandin (PG). We analysed the time course of the effect of aspirin as an indirect indicator of the origin of the PG possibly involved in anodal current-induced vasodilatation. 2. In healthy volunteers, vasodilatation, estimated from the peak cutaneous vascular conductance (CVC(peak)), was recorded in the forearm during and in the 20 min following 5 min, 0.10 mA transcutaneous anodal current application, using deionized water as a vehicle. CVC(peak) was normalized to 44°C heat-induced maximal vasodilatation and expressed in per cent values. Experiments were performed before and at 2 and 10 h, 3, 7, 10 and 14 days after blinded 1-g aspirin or placebo treatment. 3. CVC(peak) (mean±s.d.mean) after aspirin vs placebo was 13.6±14.5 vs 65.0±32.1 (P<0.05) 14.7±4.2 vs 87.5±31.9 (P<0.05), 18.1±10.2 vs 71.6±26.8 (P<0.05), 42.5±23.4 vs 73.3±26.8 (non significant, NS), 60.2±24.3 vs 75.2±26.9 (NS), 52.1±18.5 vs 67.9±32.1 (NS) at 2 and 10 h and at days 3, 7, 10 and 14 respectively. 4. Aspirin inhibition of anodal current-induced vasodilatation persists long after endothelial and smooth muscle cyclo-oxygenases are assumed to be restored. This suggests that the PG involved in this response are not endothelial- or smooth muscle-derived. The underlying mechanism of this unexpected long-lived inhibition of vasodilatation by single high dose aspirin remains to be studied