Search results for "lcsh:Astronomy"
showing 10 items of 30 documents
Four Years of Real-Time GRB Followup by BOOTES-1B (2005–2008)
2010
Four years of BOOTES-1B GRB follow-up history are summarised for the first time in the form of a table. The successfully followed events are described case by case. Further, the data are used to show the GRB trigger rate in Spain on a per-year basis, resulting in an estimate of 18 triggers and about 51 hours of telescope time per year for real-time triggers. These numbers grow to about 22 triggers and 77 hours per year if we include also the GRBs observable within 2 hours after the trigger. Copyright © 2010 Martin Jelínek et al.
Comparison of high‐speed optical observations of a lightning flash from space and the ground
2020
We analyze a nighttime negative cloud-to-ground lightning flash in Colombia observed from the ground with a high-speed camera at 5,000 images per second and from space by the Atmosphere-Space Interactions Monitor (ASIM) on the International Space Station (ISS), the Lightning Imaging Sensor also on the ISS (ISS-LIS), and the Geostationary Lightning Mapper (GLM) on GOES-16. The space instruments measure the oxygen band at 777.4 nm, allowing for direct comparisons of measurements, and the ground-based camera observes in a wide visible band. After conversion to energy emitted at the cloud top, we find a good linear correspondence of the optical energies measured by the three space instruments, …
Numerical Simulations of Jets from Active Galactic Nuclei
2019
Numerical simulations have been playing a crucial role in the understanding of jets from active galactic nuclei (AGN) since the advent of the first theoretical models for the inflation of giant double radio galaxies by continuous injection in the late 1970s. In the almost four decades of numerical jet research, the complexity and physical detail of simulations, based mainly on a hydrodynamical/magneto-hydrodynamical description of the jet plasma, have been increasing with the pace of the advance in theoretical models, computational tools and numerical methods. The present review summarizes the status of the numerical simulations of jets from AGNs, from the formation region in the neighborho…
FRAM—The Robotic Telescope for the Monitoring of the Wavelength Dependence of the Extinction: Description of Hardware, Data Analysis, and Results
2010
FRAM-F/(Ph)otometric Robotic Atmospheric Monitor is one of the atmospheric monitoring instruments at the Pierre Auger Observatory in Argentina. FRAM is an optical telescope equipped with CCD cameras and photometer, and it automatically observes a set of selected standard stars. Primarily, FRAM observations are used to obtain the wavelength dependence of the light extinction. FRAM telescope is also able to observe secondary astronomical targets, and namely the detection of optical counterparts of gamma-ray bursts has already proven to be successful. Finally, a wide-field CCD camera of FRAM can be used for rapid monitoring of atmospheric conditions along the track of particularly interesting …
Probing the Internal Structure of Magnetized, Relativistic Jets with Numerical Simulations
2016
From an observational point of view, unveiling the physical processes behind the nature of the jets emanating from radio-loud AGN demands the resolution of the structure across the jet with the highest angular resolutions. Relying on a magneto-fluid dynamical description, numerical simulations can help to characterize the internal structure of jets (transversal structure, magnetic field structure, internal shocks, etc.). In the first part of the paper, we shall discuss equilibrium models of magnetized, relativistic, infinite, axisymmetric jets with rotation propagating through a homogeneous, static, unmagnetized ambient medium. Then, these transversal equilibrium profiles will be used to bu…
PHOTOMETRY OF STARS FOR ASTRONEGATIVES WITH A SINGLE EXPOSURE
2019
The paper discusses the construction of characteristic curves for various astronegatives with a single exposure. Particular attention is paid to the question of extrapolation of the characteristic curve for the region of the weakest stars in the absence of standards. A new method for constructing an individual characteristic curve for digitized films and plates in the UBVR system has been proposed and implemented. The processing of frames of digitized plates and films with sky areas is car- ried out using LINUX/MIDAS/ROMAFOT software tools. ROMAFOT application allows us to extract astro- metric rectangular coordinates X,Y and photometric char- acteristics such as instrumental photometric ma…
ASTEROID SEARCH RESULTS FOR DIGITIZED ASTROPLATES OF 1.2m TELESCOPE IN BALDONE
2019
The work on the mass search for asteroids on astroplate images and the determination of their coordi- nates was begun in 2016. The basis for current search was the processing results of digitized photographic plates and films obtained at the observatory in Baldone in 1967-1993. Observations with a single exposure in different spectral bands were carried out using the 1.2m Schmidt telescope in Baldone. We used all observations in the U Johnson's spec- tral band (on plates) and significant part of them in V band (on films). Photometric band U was realized by combining emulsion ORWO Zu1 (Zu2 or Zu21 or Kodak 103aO or IIaO) with UG1 filter. For films with A600 emulsion and filter ZS17 a photome…
Millimeter VLBI of NGC 1052: Dynamics
2016
The LINER galaxy NGC 1052 is an ideal target to study the innermost regions of active galactic nuclei (AGN), given its close distance of about 20 Mpc. The source was observed at 29 epochs from 2005 to 2009 with the Very Long Baseline Array (VLBA) at 43 GHz. Here, we present a kinematic study of its twin-jet system from a subset of 9 epochs at 43 GHz carried out in 2005 and 2006, finding a bright central feature as the dynamic center. The resulting mean velocities of β = v / c = 0 . 46 ± 0 . 08 and β = 0 . 69 ± 0 . 02 for the western and eastern jet, respectively, give hints towards higher velocities in the eastern jet.
NEW ASTROMETRIC REDUCTION OF THE SUPERCOSMOS PLATE ARCHIVE: FIRST RESULTS
2019
The arrivals of the new more accuracy reference catalogues and also development of new meth- ods and approaches for reduction astrometric data give the new life for photographic plates archives. Gaia DR2 is not only a giant step in the astrometric accuracy allowing to measure new objects also provides plates archives ob- served in the past with modern accuracy. In this work we present the first results of astrometric reduction in the sys- tem of Gaia DR2 for some photographic plates that were obtained by UK Schmidt telescope (UKST) and digitized by the SuperCOSMOS scanning machine. The UKST is a classical Schmidt with the following parameters: mirror diameter 1.83m; focal length 3.07m; phot…
ON THE “SOLAR SYSTEM SMALL BODIES” ASTROPLATE PROJECT OF THE UKRAINIAN VIRTUAL OBSERVATORY
2019
The UkrVO Joint Digital Archive of astro- plates and the newest digitized data processing services al- lowed us to form a new approach for the creation of catalogs of astrometric and photometric characteristics of the Solar System bodies. Given this, the main goal of this approach was not only to complete the processing with the best possi- ble accuracy of high-quality and unprocessed earlier photo- graphic observations of the Solar System bodies but also to find new original data from these observations. As a result, more than 6,500 new astrometric positions and stellar magnitudes of asteroids, and 3,036 positions of outer planets (Pluto, Uranus, Neptune, Saturn, Jupiter) and their satelli…