Research
List of scientific articles I wrote or contributed. These were published in professional peer-reviewed journals. The list is in descending order. If you are interested, and want to know more about the study click on the title and read the full article in the official site of the journal. Or feel free to contact me.
Könyves-Tóth, R.; Vinkó, J.; Ordasi, A.; Sárneczky, K.; Bódi, A.; Cseh, B.; Csörnyei, G.; Dencs, Z.; Hanyecz, O.; Ignácz, B.; Kalup, Cs.; Kriskovics, L.; Pál, A.; Seli, B.; Sódor, Á.; Szakáts, R.; Székely, P.; Varga-Verebélyi, E.; Vida, K.; Zsidi, G.
We present a photometric study of 17 SNe Ia based on multi-color (Johnson-Cousins-Bessell BVRI) data taken at Piszkéstető mountain station of Konkoly Observatory, Hungary between 2016 and 2018. We analyze the light curves (LCs) using the publicly available LC-fitter SNooPy2 to derive distance and reddening information. The bolometric LCs are fit with a radiation-diffusion Arnett model to get constraints on the physical parameters of the ejecta: the optical opacity, the ejected mass and the initial nickel mass in particular. MORE
Podlewska-Gaca, E.; Marciniak, A.; Alí-Lagoa, V.; Bartczak, P.; Müller, T. G.; Szakáts, R.; Duffard, R.; Molnár, L.; Pál, A.; Butkiewicz-Bąk, M.; Dudziński, G.; Dziadura, K.; Antonini, P.; Asenjo, V.; Audejean, M.; Benkhaldoun, Z.; Behrend, R.; Bernasconi, L.; Bosch, J. M.; Chapman, A. Dintinjana, B.; Farkas, A.; Ferrais, M.; Geier, S.; Grice, J.; Hirsh, R.; Jacquinot, H.; Jehin, E.; Jones, A.; Molina, D.; Morales, N.; Parley, N.; Poncy, R.; Roy, R.; Santana-Ros, T.; Seli, B.; Sobkowiak, K.; Verebélyi, E.; Żukowski, K.
Thanks to the Gaia mission, it will be possible to determine the masses of approximately hundreds of large main belt asteroids with very good precision. We currently have diameter estimates for all of them that can be used to compute their volume and hence their density. However, some of those diameters are still based on simple thermal models, which can occasionally lead to volume uncertainties as high as 20–30%. MORE
Marton, G.; Ábrahám, P.; Szegedi-Elek, E.; Varga, J.; Kun, M.; Kóspál, Á.; Varga-Verebélyi, E.; Hodgkin, S.; Szabados, L.; Beck, R.; Kiss, Cs.
The second Gaia Data Release (DR2) contains astrometric and photometric data for more than 1.6 billion objects with mean Gaia G magnitude less than 20.7, including many Young Stellar Objects (YSOs) in different evolutionary stages. In order to explore the YSO population of the Milky Way, we combined the Gaia DR2 data base with Wide-field Infrared Survey Explorer (WISE) and Planck measurements and made an all-sky probabilistic catalogue of YSOs using machine learning techniques, such as Support Vector Machines, Random Forests, or Neural Networks. Our input catalogue contains 103 million objects from the DR2xAllWISE cross-match table. We classified each object into four main classes: YSOs, extragalactic objects, main-sequence stars, and evolved stars. MORE
Bognár, Zs; Paparó, M.; Sódor, Á.; Jenei, D. I.; Kalup, Cs; Bertone, E.; Chavez-Dagostino, M.; Montgomery, M. H.; Győrffy, Á.; Molnár, L.; Ollé, H.; Pápics, P. I.; Plachy, E.; Verebélyi, E.
We summarize our findings on three cool ZZ Ceti type pulsating white dwarfs. We determined eight independent modes in HS 0733 + 4119, of which seven are new findings. For GD 154, we detected two new eigenmodes, and the recurrence of the pulsational behaviour first observed in 1977. We discuss that GD 154 does not only vary its pulsations between a multiperiodic and a quasi-monoperiodic phase, but there are also differences between the relative amplitudes of the near-subharmonics observed in the latter phase. In the complex pulsator, Ross 808, we compared the pre- and post Whole Earth Telescope campaign measurements, and determined two new frequencies besides the ones observed during the campaign. Studying these stars can contribute to better understanding of pulsations close to the empirical ZZ Ceti red edge. All three targets are in that regime of the ZZ Ceti instability strip where short-term amplitude variations or even outbursts are likely to occur, which are not well-understood theoretically. MORE
Bognár, Zs.; Paparó, M.; Molnár, L.; Pápics, P. I.; Plachy, E.; Verebélyi, E.; Sódor, Á.
G 207-9 and LP 133-144 are two rarely observed ZZ Ceti stars located in the middle and close to the blue edge of the ZZ Ceti instability domain, respectively. We aimed to observe them at least during one observing season at Konkoly Observatory with the purpose of extending the list of known pulsation modes for asteroseismic investigations and detect any significant changes in their pulsational behaviour. We determined five and three new normal modes of G 207-9 and LP 133-144, respectively. MORE
Müller, T. G.; Marciniak, A.; Kiss, Cs.; Duffard, R.; Alí-Lagoa, V.; Bartczak, P.; Butkiewicz-Bąk, M.; Dudziński, G.; Fernández-Valenzuela, E.; Marton, G.; Morales, N.; Ortiz, J. -L.; Oszkiewicz, D.; Santana-Ros, T.; Szakáts, R.; Santos-Sanz, P.; Takácsné Farkas, A.; Varga-Verebélyi, E.
The combination of visible and thermal data from the ground and astrophysics space missions is key to improving the scientific understanding of near-Earth, main-belt, trojans, centaurs, and trans-Neptunian objects. To get full information on a small sample of selected bodies we combine different methods and techniques: lightcurve inversion, stellar occultations, thermophysical modelling, radiometric methods, radar ranging and adaptive optics imaging. The SBNAF project will derive size, spin and shape, thermal inertia, surface roughness, and in some cases bulk densities and even internal structure and composition, for objects out to the most distant regions in the Solar System. MORE
SUPERNOVAE
Prentice, S. J.; Ashall, C.; Mazzali, P. A.; Zhang, J. -J.; James, P. A.; Wang, X. -F.; Vinkó, J.; Percival, S.; Short, L.; Piascik, A.; Huang, F.; Mo, J.; Rui, L. -M.; Wang, J. -G.; Xiang, D. -F.; Xin, Y. -X.; Yi, W. -M.; Yu, X. -G.; Zhai, Q.; Zhang, T. -M. Hosseinzadeh, G.; Howell, D. A.; McCully, C.; Valenti, S.; Cseh, B.; Hanyecz, O.; Kriskovics, L.; Pál, A.; Sárneczky, K.; Sódor, Á.; Szakáts, R.; Székely, P.; Varga-Verebélyi, E.; Vida, K.; Bradac, M.; Reichart, D. E.; Sand, D.; Tartaglia, L.
The optical observations of Ic-4 supernova (SN) 2016coi/ASASSN-16fp from 2 to 450 d after explosion, are presented along with analysis of its physical properties. The SN shows the broad lines associated with SNe Ic-3/4 but with a key difference. The early spectra display a strong absorption feature at 5400 Å which is not seen in other SNe Ic-3/4 at this epoch. This feature has been attributed to He I in the literature. Spectral modelling of the SN in the early photospheric phase suggests the presence of residual He in a C/O dominated shell. However, the behaviour of the He I lines is unusual when compared with He-rich SNe, showing relatively low velocities and weakening rather than strengthening over time. MORE
SMALL BODIES NEAR AND FAR
Ortiz, J. L.; Santos-Sanz, P.; Sicardy, B.; Benedetti-Rossi, G.; Bérard, D.; Morales, N.; Duffard, R.; Braga-Ribas, F.; Hopp, U.; Ries, C.; Nascimbeni, V.; Marzari, F.; Granata, V.; Pál, A.; Kiss, C.; Pribulla, T.; Komžík, R.; Hornoch, K.; Pravec, P.; Bacci, P. Maestripieri, M.; Nerli, L.; Mazzei, L.; Bachini, M.; Martinelli, F.; Succi, G.; Ciabattari, F.; Mikuz, H.; Carbognani, A.; Gaehrken, B.; Mottola, S.; Hellmich, S.; Rommel, F. L.; Fernández-Valenzuela, E.; Campo Bagatin, A.; Cikota, S.; Cikota, A.; Lecacheux, J.; Vieira-Martins, R.; Camargo, J. I. B.; Assafin, M.; Colas, F.; Behrend, R.; Desmars, J.; Meza, E.; Alvarez-Candal, A.; Beisker, W.; Gomes-Junior, A. R.; Morgado, B. E.; Roques, F.; Vachier, F.; Berthier, J.; Mueller, T. G.; Madiedo, J. M.; Unsalan, O.; Sonbas, E.; Karaman, N.; Erece, O.; Koseoglu, D. T.; Ozisik, T.; Kalkan, S.; Guney, Y.; Niaei, M. S.; Satir, O.; Yesilyaprak, C.; Puskullu, C.; Kabas, A.; Demircan, O.; Alikakos, J.; Charmandaris, V.; Leto, G.; Ohlert, J.; Christille, J. M.; Szakáts, R.; Takácsné Farkas, A.; Varga-Verebélyi, E.; Marton, G.; Marciniak, A.; Bartczak, P.; Santana-Ros, T.; Butkiewicz-Bąk, M.; Dudziński, G.; Alí-Lagoa, V.; Gazeas, K.; Tzouganatos, L.; Paschalis, N.; Tsamis, V.; Sánchez-Lavega, A.; Pérez-Hoyos, S.; Hueso, R.; Guirado, J. C.; Peris, V.; Iglesias-Marzoa, R.
Haumea—one of the four known trans-Neptunian dwarf planets—is a very elongated and rapidly rotating body. In contrast to other dwarf planets, its size, shape, albedo and density are not well constrained. The Centaur Chariklo was the first body other than a giant planet known to have a ring system, and the Centaur Chiron was later found to possess something similar to Chariklo’s rings. Here we report observations from multiple Earth-based observatories of Haumea passing in front of a distant star (a multi-chord stellar occultation). Secondary events observed around the main body of Haumea are consistent with the presence of a ring with an opacity of 0.5, width of 70 kilometres and radius of about 2,287 kilometres. The ring is coplanar with both Haumea’s equator and the orbit of its satellite Hi’iaka.MORE
INFRARED SPACE
Dobos, László; Varga-Verebélyi, Erika; Verdugo, Eva; Teyssier, David; Exter, Katrina; Valtchanov, Ivan; Budavári, Tamás; Kiss, Csaba
Data from the Herschel Space Observatory is freely available to the public but no uniformly processed catalogue of the observations has been published so far. To date, the Herschel Science Archive does not contain the exact sky coverage (footprint) of individual observations and supports search for measurements based on bounding circles only. Drawing on previous experience in implementing footprint databases, we built the Herschel Footprint Database and Web Services for the Herschel Space Observatory to provide efficient search capabilities for typical astronomical queries. The database was designed with the following main goals in mind: (a) provide a unified data model for meta-data of all instruments and observational modes, (b) quickly find observations covering a selected object and its neighbourhood, (c) quickly find every observation in a larger area of the sky, (d) allow for finding solar system objects crossing observation fields. As a first step, we developed a unified data model of observations of all three Herschel instruments for all pointing and instrument modes. Then, using telescope pointing information and observational meta-data, we compiled a database of footprints. MORE