Introducing high-school and university students to practical astronomy via Virtual observatory tools

Large-scale astronomical surveys from the last decades have turned the usage of catalogs and archival data into one of the primary skills of contemporary observational astronomers. Virtual observatory tools give high-school and university students the opportunity to conduct astronomical research by themselves, using freely available observational data. For this purpose, they need basic theoretical knowledge in astronomy. The current paper includes a review of this theoretical knowledge as well as a review of Virtual observatory tools suitable for students. Results obtained by students using VO tools at the Beli Brezi Summer School in Astronomy and Astrophysics are presented as well.

Application of spherical Slepian functions to the inversion of virtual observatory satellite magnetic data into localised regions of flow on the core-mantle boundary

<p>Spherical Slepian functions (or ‘Slepian functions’) are mathematical functions which can be used to decompose potential fields, as represented by spherical harmonics, into smaller regions covering part of a spherical surface. This allows a spatio-spectral trade-off between aliasing of the signal at the boundary edges while constraining it within a region of interest. While Slepian functions have previously been applied to geodetic and crustal magnetic data, this work further applies Slepian functions to flows on the core-mantle boundary. There are two main reasons for restricting flow models to certain parts of the core surface. Firstly, we have reason to believe that different dynamics operate in different parts of the core (such as under LLSVPs) while, secondly, the modelled flow is ambiguous over certain parts of the surface (when applying flow assumptions). Spherical Slepian functions retain many of the advantages of our usual flow description, concerning for example the boundary conditions it must satisfy, and allowing easy calculation of the power spectrum, although greater initial computational effort is required.</p><p><br>In this work, we apply Slepian functions to core flow models by directly inverting from satellite virtual observatory magnetic data into regions of interest. We successfully demonstrate the technique and current short comings by showing whole core surface flow models, flow within a chosen region, and its corresponding complement. Unwanted spatial leakage is generated at the region edges in the separated flows but to less of an extent than when using spherical Slepian functions on existing flow models. The limited spectral content we can infer for core flows is responsible for most, if not all, of this leakage. Therefore, we present ongoing investigations into the cause of this leakage, and to highlight considerations when applying Slepian functions to core surface flow modelling.</p>

The Digitized First Byurakan Survey (DFBS) as UNESCO Documentary Heritage

The famous Markarian Survey (or the First Byurakan Survey, FBS) was carried out in 1965-1980. Its 2000 plates were digitized in 2002-2007 and the Digitized FBS (DFBS, www.aras.am/Dfbs/dfbs.html) was created. New science projects have been conducted based on this low-dispersion spectroscopic material. The Armenian Virtual Observatory (ArVO, www.aras.am/Arvo/arvo.htm) database accommodates all new data. The project was conducted in collaboration with the Italian, USA and German scientists, as well as the Armenian Institute of Informatics and Automation Problems (IIAP) and continued during 6 years in 2002-2007. Markarian Survey and its digitized version were included in UNESCO Documentary Heritage “Memory of the World” International Register in 2011 as one of the rare heritage items from science.

Ultracool dwarfs in deep extragalactic surveys using the virtual observatory: ALHAMBRA and COSMOS

ABSTRACT Ultracool dwarfs (UCDs) encompass a wide variety of compact stellar-like objects with spectra classified as late-M, L, T, and Y. Most of them have been discovered using wide-field imaging surveys. The Virtual Observatory (VO) has proven to be of great utility to efficiently exploit these astronomical resources. We aim to validate a VO methodology designed to discover and characterize UCDs in deep extragalactic surveys like Advance Large Homogeneous Area Medium-Band Redshift Astronomical (ALHAMBRA) and Cosmological Evolution Survey (COSMOS). Three complimentary searches based on parallaxes, proper motions and colours, respectively, were carried out. A total of 897 candidate UCDs were found, with only 16 previously reported in SIMBAD. Most of the new UCDs reported here are likely late-M and L dwarfs because of the limitations imposed by the utilization of optical (Gaia DR2 and r-band) data. We complement ALHAMBRA and COSMOS photometry with other catalogues in the optical and infrared using VOSA, a VO tool that estimates effective temperatures from the spectral energy distribution fitting to collections of theoretical models. The agreement between the number of UCDs found in the COSMOS field and theoretical estimations together with the low false-negative rate (known UCDs not discovered in our search) validates the methodology proposed in this work, which will be used in the forthcoming wide and deep surveys provided by the Euclid space mission. Simulations of Euclid number counts for UCDs detectable in different photometric passbands are presented for a wide survey area of 15 000 deg2, and the limitations of applicability of Euclid data to detect UCDs using the methods employed in this paper are discussed.

The PVOL database in Europlanet 2024 RI

<p>PVOL is an online database of amateur observations of solar system planets hosted by the University of the Basque Country at http://pvol2.ehu.es/ [1]. PVOL stands for Planetary Virtual Observatory and Laboratory and is one of the data services integrated in VESPA: a large collection of data services integrated in the Virtual European Solar and Planetary Access services using the same data access protocol (EPN-TAP) [2]. VESPA is an integral part of the Europlanet 2020 and 2024 Research Infrastructures and PVOL is one of its most used services. PVOL accumulates images provided by more than 300 amateur observers distributed through the globe and currently contains more than 47,000 image files. Most of the data correspond to image observations of Jupiter (67%) and Saturn (22%), but PVOL contains also useful data from Venus, Mars, Uranus and Neptune and some smaller collections of objects with no atmosphere (the Moon and Galilean satellites). In this contribution we document future plans for the service which will be carried out through 2021-2023 and we show the scientific potential of the data available in PVOL.</p> <p>Future plans for PVOL include frequent observation alerts, integration in the database of navigation files of the images from the popular WinJupos software (ims files), addition of amateur spectra of the giant planets, and a search engine and new data service of Jupiter maps obtained from the JunoCam instrument on the Juno mission that will also be integrated in PVOL/VESPA. This will allow to perform combined searches of data obtained close in time from amateurs (PVOL), HST (queries of HST images are also integrated in VESPA) and JunoCam (new service).</p> <p>The science potential of amateur data comes from the availability of long-term data (PVOL contains Jupiter data since 2000 and Mars and Venus data since 2016), frequent observations (several daily observations of each planet close to their oppositions capable to cover complete longitudes of each planet) and high-resolution images provided by key contributors, with some of them capable to resolve highly-contrasted features of 0.05-0.10 arcsec. We review recent trends in analysis of this data from an analysis of scientific publications partially or highly based on data obtained from PVOL. We show that amateur observations remain as a valuable resource for high-impact science on modern research on different planets (3-5).</p> <p><strong>Acknowledgements</strong></p> <p>Europlanet 2024 RI has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 871149. We are very grateful to the ensemble of amateur astronomers sending their data to PVOL. We are in debt by the quality of many of these observations and the regular observations provided by many of them requiring long sleepless nights and even longer days of detailed image processing.</p> <p><strong>References</strong></p> <p>(1) Hueso et al., The Planetary Virtual Observatory and Laboratory (PVOL) and its integration into the Virtual European Solar and Planetary Access (VESPA). Planet. Space Science, 150, 22-35 (2018).</p> <p>(2) Erard et al., VESPA: A community-driven Virtual Observatory in Planetary Science. Planet. Space Science, 150, 65-85 (2018).</p> <p>(3) Sánchez-Lavega et al., The impact of a large object on Jupiter in 2009 July, Astrophysical Journal Letters, 715, L155 (2010).</p> <p>(4) Sánchez-Lavega et al., An extremely high altitude plume seen at Mars morning terminator. Nature, 518, 525-528 (2015).</p> <p>(5) Sánchez-Lavega et al., A complex storm system in Saturn’s north polar atmosphere in 2018, Nature Astronomy, 4, 180-187 (2020).</p>

Searching for debris discs in the 30 Myr open cluster IC 4665

Context. Debris discs orbiting young stars are key to understanding dust evolution and the planetary formation process. We take advantage of a recent membership analysis of the 30 Myr nearby open cluster IC 4665 based on the Gaia and DANCe surveys to revisit the disc population of this cluster. Aims. We aim to study the disc population of IC 4665 using Spitzer (MIPS and IRAC) and WISE photometry. Methods. We use several colour–colour diagrams with empirical photospheric sequences to detect the sources with an infrared excess. Independently, we also fit the spectral energy distribution (SED) of our debris-disc candidates with the Virtual Observatory SED analyser (VOSA) which is capable of automatically detecting infrared excesses and provides effective temperature estimates. Results. We find six candidate debris-disc host stars (five with MIPS and one with WISE), two of which are new candidates. We estimate a disc fraction of 24 ± 10% for the B–A stars, where our sample is expected to be complete. This is similar to what has been reported in other clusters of similar ages (Upper Centaurus Lupus, Lower Centaurus Crux, the β Pictoris moving group, and the Pleiades). For solar-type stars we find a disc fraction of 9 ± 9%, which is lower than that observed in regions with comparable ages. Conclusions. Our candidate debris-disc host stars are excellent targets to be studied with ALMA or the future James Webb Space Telescope (JWST).