34 research outputs found
Astrokit -- an Efficient Program for High-Precision Differential CCD Photometry and Search for Variable Stars
Having a need to perform differential photometry for tens of thousands stars
in a several square degrees field, we developed Astrokit program. The software
corrects the star brightness variations caused by variations of atmospheric
transparency: to this end, the program selects for each star an individual
ensemble of reference stars having similar magnitudes and positions in the
frame. With ten or more reference stars in the ensemble, the differences
between their spectral types and the spectral type of the object studied become
unimportant. Astrokit searches for variable stars using Robust Median
Statistics criterion, which allows candidate variables to be selected more
efficiently than by analyzing the standard deviation of star magnitudes. The
software allows very precise automatic analysis of long inhomogeneous sets of
photometric observations of a large number of objects to be performed, making
it possible to find "hot Jupiter" type exoplanet transits and low-amplitude
variables. We describe the algorithm of the program and the results of its
application to reduce the data of the photometric sky survey in Cygnus as well
as observations of the open cluster NGC188 and the transit of the exoplanet
WASP-11 b / HAT-P-10 b, performed with the MASTER-II-URAL telescope of the
Kourovka Astronomical Observatory of the Ural Federal University.Comment: to be published in Astrophysical Bulletin, Vol. 69, No.
Trajectory Retrieval and Component Investigations of Southern Polar Stratosphere Based on High Resolution Spectroscopy of Totally Eclipsed Moon Surface
Abstract. In this paper we present the high resolution spectral observations of the fragment of lunar surface during the total lunar eclipse of December 10, 2011. The observations were carried out with the fiber-fed echelle spectrograph at 1.2-m telescope in Kourovka Astronomical observatory (Ural mountains, central Russia). The observed radiation is transferred by tangent trajectory through the southern polar stratosphere before the reflection from the Moon and spectra contain a number of absorption bands of atmospheric gases (O 2 , O 3 , O 4 , NO 2 , H 2 O). High resolution analysis of three O 2 bands and O 4 absorption effects is used to trace the effective trajectory of solar emission through the stratosphere and to detect the contribution of scattered light. Bands of other gases allow us to measure their abundances along the trajectory
Master Robotic Net
The main goal of the MASTER-Net project is to produce a unique fast sky
survey with all sky observed over a single night down to a limiting magnitude
of 19 - 20mag. Such a survey will make it possible to address a number of
fundamental problems: search for dark energy via the discovery and photometry
of supernovas (including SNIa), search for exoplanets, microlensing effects,
discovery of minor bodies in the Solar System and space-junk monitoring. All
MASTER telescopes can be guided by alerts, and we plan to observe prompt
optical emission from gamma-ray bursts synchronously in several filters and in
several polarization planes.Comment: 10 pages, 8 figure
MASTER prompt and follow-up GRB observations
There are the results of gamma-ray bursts observations obtained using the
MASTER robotic telescope in 2007 - 2009. We observed 20 error-boxes of
gamma-ray bursts this period.The limits on their optical brightnesses have been
derived. There are 5 prompt observations among them, obtained at our very wide
field cameras. Also we present the results of the earliest observations of the
optical emission of the gamma-ray bursts GRB 050824 and GRB 060926.Comment: 10 pages, 2 figure
Transient detections and other real-time data processing from wide-field chambers MASTER-VWF
At present time Robotic observatory making is of current importance. Having a
large field of view and being able to point at anywhere, Robotic astronomical
systems are indispensable when they looking for transients like grb, supernovae
explosions, novae etc, as it's impossible in these cases to foresee what you
should point you telescope at and when. In work are described prompt GRB
observations received on wide-field chambers MASTER-VWF, and also methods of
the images analysis and transients classifications applied in real-time data
processing in this experiment. For 7 months of operation 6 synchronous
observations of gamma-ray burst had been made by MASTER VWF in Kislovodsk and
Irkutsk. In all cases a high upper limits have been received (see tabl \ref
{tab_grbwf} and fig. \ref {allgrb}).Comment: 21 pages, 21 figure, 2 tables, Advances in Astronomy in pres
First results of the Kourovka Planet Search: discovery of transiting exoplanet candidates in the first three target fields
We present the first results of our search for transiting exoplanet
candidates as part of the Kourovka Planet Search (KPS) project. The primary
objective of the project is to search for new hot Jupiters which transit their
host stars, mainly in the Galactic plane, in the magnitude range of 11 to
14 mag. Our observations were performed with the telescope of the MASTER
robotic network, installed at the Kourovka astronomical observatory of the Ural
Federal University (Russia), and the Rowe-Ackermann Schmidt Astrograph,
installed at the private Acton Sky Portal Observatory (USA). As test
observations, we observed three celestial fields of size deg
during the period from 2012 to 2015. As a result, we discovered four transiting
exoplanet candidates among the 39000 stars of the input catalogue. In this
paper, we provide the description of the project and analyse additional
photometric, spectral, and speckle interferometric observations of the
discovered transiting exoplanet candidates. Three of the four transiting
exoplanet candidates are most likely astrophysical false positives, while the
nature of the fourth (most promising) candidate remains to be ascertained.
Also, we propose an alternative observing strategy that could increase the
project's exoplanet haul.Comment: 11 pages, 16 figures; Accepted for publication in Monthly Notices of
the Royal Astronomical Society 201
Supernova search with active learning in ZTF DR3
We provide the first results from the complete SNAD adaptive learning
pipeline in the context of a broad scope of data from large-scale astronomical
surveys. The main goal of this work is to explore the potential of adaptive
learning techniques in application to big data sets. Our SNAD team used Active
Anomaly Discovery (AAD) as a tool to search for new supernova (SN) candidates
in the photometric data from the first 9.4 months of the Zwicky Transient
Facility (ZTF) survey, namely, between March 17 and December 31 2018 (58194 <
MJD < 58483). We analysed 70 ZTF fields at a high galactic latitude and
visually inspected 2100 outliers. This resulted in 104 SN-like objects being
found, 57 of which were reported to the Transient Name Server for the first
time and with 47 having previously been mentioned in other catalogues, either
as SNe with known types or as SN candidates. We visually inspected the
multi-colour light curves of the non-catalogued transients and performed
fittings with different supernova models to assign it to a probable photometric
class: Ia, Ib/c, IIP, IIL, or IIn. Moreover, we also identified unreported
slow-evolving transients that are good superluminous SN candidates, along with
a few other non-catalogued objects, such as red dwarf flares and active
galactic nuclei. Beyond confirming the effectiveness of human-machine
integration underlying the AAD strategy, our results shed light on potential
leaks in currently available pipelines. These findings can help avoid similar
losses in future large-scale astronomical surveys. Furthermore, the algorithm
enables direct searches of any type of data and based on any definition of an
anomaly set by the expert.Comment: 22 pages with appendix, 12 figures, 2 tables, accepted for
publication in Astronomy and Astrophysic
Trajectory Retrieval and Component Investigations of Southern Polar Stratosphere Based on High Resolution Spectroscopy of Totally Eclipsed Moon Surface
In this paper we present the high resolution spectral observations of the
fragment of lunar surface during the total lunar eclipse of December 10, 2011.
The observations were carried out with the fiber-fed echelle spectrograph at
1.2-m telescope in Kourovka Astronomical observatory (Ural mountains, central
Russia). The observed radiation is transferred by tangent trajectory through
the southern polar stratosphere before the reflection from the Moon and spectra
contain a number of absorption bands of atmospheric gases (O2, O3, O4, NO2,
H2O). High resolution analysis of three O2 bands and O4 absorption effects is
used to trace the effective trajectory of solar emission through the
stratosphere and to detect the contribution of scattered light. Bands of other
gases allow us to measure their abundances along the trajectory.Comment: 13 pages, 9 figure