Glueball as a bound state in the self-dual homogeneous gluon field

Using a simple relativistic QFT model of scalar fields we demonstrate that the analytic confinement (propagator is an entire function in the complex $p^2$--plane) and the weak coupling constant lead to the Regge behaviour of the two-particle bound states. In QCD we assume that the gluon vacuum is realized by the self-dual homogeneous classical field which is the solution of the Yang-Mills equations. This assumption leads to analytical confinement of quarks and gluons. We extract the colorless $0^{++}$ two-gluon state from the QCD generating functional in the one-gluon exchange approximation. The mass of this bound state is defined by the Bethe-Salpeter equation. The glueball mass is $1765~{\rm MeV}$ for $\alpha_s=0.33$ if the gluon condensate is $=0.012~{\rm GeV}^4$.Comment: 3 pages. Parallel talk given at the 5rd International Conference on Quark Confinement and the Hadron Spectrum (Confinement V), Gargnano, Italy, September 10-14, 2002. To appear in the proceeding

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.

Research of discovered transiting exoplanet candidates by means of photometric and spectroscopic observations using telescopes of Kourovka astronomical observatory of UrFU

В работе представлены результаты дополнительных наблюдений двух кандидатов в транзитные экзопланеты, открытых в созвездии Лебедя в ходе пилотного фотометрического обзора неба, выполненного в Коуровской астрономической обсерватории Уральского федерального университета в 2012 году. Дополнительные наблюдения, проведенные с помощью телескопа МАСТЕР-Урал и 1.2-метрового телескопа Коуровской астрономической обсерватории, позволили уточнить характеристики систем: периоды орбитального обращения найденных кандидатов в экзопланеты и наклонения их орбит, отношение радиусов родительских звезд и кандидатов в экзопланеты, а также спектральные классы родительских звезд.Follow-up observations` results of two transiting exoplanet candidates discovered in the Cygnus during a pilot photometric sky survey performed in Kourovka astronomical observatory of Ural Federal University in 2012 are presented. Follow-up observations were conducted with the MASTER Ural telescope and 1.2 -meter telescope of Kourovka astronomical observatory. Observations allowed determining properties of the systems more precisely: the orbital periods of exoplanet candidates, inclinations of their orbits, the ratio of the radii of the parent stars and exoplanet candidates, and the spectral classes of the parent stars.Программа развития УрФУ на 2013 год (п.1.2.2.3

GPU-based framework for detecting small Solar System bodies in targeted exoplanet surveys

Small Solar System bodies are pristine remnants of Solar System formation, which provide valuable insights for planetary science and astronomy. Their discovery and cataloging also have strong practical implications to life on Earth as the nearest asteroids could pose a serious impact threat. Concurrently with dedicated observational projects, searches for small bodies have been performed on numerous archival data sets from different facilities. Here, we present a framework to increase the scientific return of an exoplanet transit-search survey by recovering serendipitous detections of small bodies in its daily and archival data using a GPU-based synthetic tracking algorithm. As a proof of concept, we analysed $12 \times 12 \mathrm{arcmin^2}$ sky fields observed by the 1-m telescopes of the SPECULOOS survey. We analysed 90 sky fields distributed uniformly across the sky as part of the daily search for small bodies and 21 archival fields located within 5 deg from the ecliptic plane as part of the archival search (4.4 deg$^2$ in total). Overall, we identified 400 known objects of different dynamical classes from Inner Main-belt Asteroids to Jupiter Trojans and 43 potentially new small bodies with no priors on their motion. We were able to reach limiting magnitude for unknown objects of $V$=23.8 mag, and a retrieval rate of $\sim$80% for objects with $V<$22 mag and $V<$23.5 mag for the daily and archival searches, respectively. SPECULOOS and similar exoplanet surveys can thus serve as pencil-beam surveys for small bodies and probe parameter space beyond $V$=22 mag.Comment: Accepted for publication in MNRAS (Monthly Notices of the Royal Astronomical Society), 11 pages, 11 figure

Ground-based follow-up observations of TRAPPIST-1 transits in the near-infrared

The TRAPPIST-1 planetary system is a favorable target for the atmospheric characterization of temperate earth-sized exoplanets by means of transmission spectroscopy with the forthcoming James Webb Space Telescope (JWST). A possible obstacle to this technique could come from the photospheric heterogeneity of the host star that could affect planetary signatures in the transit transmission spectra. To constrain further this possibility, we gathered an extensive photometric data set of 25 TRAPPIST-1 transits observed in the near-IR J band (1.2 $\mu$m) with the UKIRT and the AAT, and in the NB2090 band (2.1 $\mu$m) with the VLT during the period 2015-2018. In our analysis of these data, we used a special strategy aiming to ensure uniformity in our measurements and robustness in our conclusions. We reach a photometric precision of $\sim0.003$ (RMS of the residuals), and we detect no significant temporal variations of transit depths of TRAPPIST-1 b, c, e, and g over the period of three years. The few transit depths measured for planets d and f hint towards some level of variability, but more measurements will be required for confirmation. Our depth measurements for planets b and c disagree with the stellar contamination spectra originating from the possible existence of bright spots of temperature 4500 K. We report updated transmission spectra for the six inner planets of the system which are globally flat for planets b and g and some structures are seen for planets c, d, e, and f.Comment: accepted for publication in MNRA