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EXPLANATION: Exoplanet and transient events investigation project, first results
Amid the global boom of recent decades, programs of searching for and investigating extrasolar planets (exoplanets) in Russia were until recently extremely limited due to the lack of adequate scientific instruments. With funding from the Russian Science Foundation and two grants from the Ministry of Education and Science (2014-2022), SAO RAS created a complex of wide-angle robotic telescopes to search for exoplanets and non-stationary (transient) events, and a high-accuracy planetary spectrograph that allows detecting the radial velocity variations of parent stars under the influence of exoplanets. As a result, the project abbreviated as EXPLANATION (EXoPLANet And Transient events InvestigatiON) started in the Special Astrophysical Observatory of the Russian Academy of Sciences. Its goal is a massive search and study of exoplanets and non-stationary events in the Universe. In less than two years, the first ten exoplanets and exoplanet candidates were discovered within the project and studied using photometric transits and Doppler spectroscopy methods. An example of two such events is shown in Fig. 1.
Authors:
Valyavin G.G., Valeev A.F., Beskin G.M., Fabrika S.N., Galazutdinov G.A., Vlasyuk V.V. in cooperation with Yakovlev O. Ya. (SAO RAS, IKI RAS), Tavrov A.V., Korablev O.I. (IKI RAS)
Published:
1. Doppler confirmation of TESS planet candidate TOI-1408.01: grazing transit and likely eccentric orbit, Galazutdinov G.A., Baluev R.V., Valyavin G. et al, Monthly Notices of the Royal Astronomical Society: Letters, Volume 526, Issue 1, pp.L111-L115, DOI: 10.1093/mnrasl/slad127
2. Eight Exoplanet Candidates in SAO Survey, Yakovlev O. Ya., Valeev A. F., Valyavin G. G. et al., Astrophysical Bulletin, Volume 78, Issue 1, p.79-93, DOI: 10.1134/S1990341323010108
3. Exoplanet Two-Square Degree Survey With SAO RAS Robotic Facilities, Yakovlev O. Ya., Valeev, Azamat F., Valyavin, Gennady G., Tavrov, Alexander V. et al. Frontiers in Astronomy and Space Sciences, vol. 9, id. 903429, DOI: 10.3389/fspas.2022.903429
4. EXPLANATION: Exoplanet and Transient Event Investigation Project – Optical Facilities and Solutions, Valyavin G., Beskin G., Valeev A., Galazutdinov, G. et al. Photonics, Volume 9, Issue 12, id.950, DOI: 10.3390/photonics9120950
Blazar classification based on multiparameter cluster analysis
Implementing multiparameter cluster analysis for the blazars from the Roma BZCAT catalog, we developed their classification that reflects a continuous variation of properties from the BL Lac-type objects to flat-spectrum radio quasars (FSRQs).
Using world-best databases as well as multi-frequency measurements obtained with RATAN-600, we selected a set of characteristics that described the spectral energy distribution from radio waves to gamma rays, radio luminosity, and distance to a blazar. With these characteristics we carried out a multiparameter cluster analysis using two machine learning methods, which showed similar (~90%) results.
The resulting classification is validated by comparison with the known blazar types: BL Lacs, FSRQs, high synchrotron peaked blazars (HSPs), and blazars detected in the TeV range. A continuous variation of properties along the obtained groups is observed. The group of HSP blazars stands out against the overall distribution.
On this example of a sample of blazars, we demonstrate the effectiveness of the clustering technique for objective analysis of multiparameter arrays of experimental data.
Authors:
Kudryavtsev D.O., Sotnikova Yu.V., Stolyarov V.A., Mufakharov T.V., Vlasyuk V.V., Cherepkova Yu.V. (SAO RAS)
Published:
Kudryavtsev D., Sotnikova Y., Stolyarov V., et al., 2023. Acta Astrophysica Taurica, vol. 4, no. 3, pp. 5–10. DOI: 10.34898/aat.vol4.iss3.pp5-10
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