we offer multiple project opportunities in the group of extrasolar planets in Stellar department at AsU Ondrejov. The projects can be related to transmission spectroscopy of exoplanetary atmospheres on archival data or to detection and charatcerization of exoplanets with help of radial velocities and spectroscopy. We are working with an echelle spectrograph installed at Perek 2-m telescope in Ondrejov and with instrumentation of large observatories such as ESO. We would welcome early career researchers for any duration from 2 months. In case, you would be interested, please contact Petr Kabath.
We propose to study selected groups of pulsating stars of the upper main sequence. Those are delta Scuti, gamma Doradus, rapidly rotating Ap (roAp), and Slowly Pulsating B-type (SPB) stars. Data sets are available from ground based (ASAS-3, OGLE, and SuperWASP) as well as spaced based (CoRoT, Kepler, and MOST) instruments. Not only the pulsational behaviour over many years, but also short-time changes of the amplitude and period are interesting. Another important point is the incidence of apparent non-variable stars in the same region of the HRD. Which astrophysical parameters discriminate these two groups? With the help of Gaia data, photometric, and spectroscopic observations, more light should be shed on these topics. The results will be vital for current pulsational models. In case, you would be interested, please contact Ernst Paunzen.
The investigation of stars in open clusters has several advantages compared to any galactic field object. In general, open clusters contain stars which are bound by gravitation. The members of an individual open cluster have the following characteristics which help to determine the listed astrophysical parameters
Since all kinds of variable (eclipsing binaries, delta Scuti, or beta Cephei, just to mention a few of the whole zoo of objects), peculiar stars (CP stars and Blue Stragglers), binaries and so on, are available in open clusters, several most important astrophysical processes (for example diffusion, mass loss and rotation) can be traced in correlation with the local as well as global Galactic environment. In particular, e.g. the evolution of individual star groups can be studied in dependence on the age and metallicity.
For the study of stellar clusters in the Milky Way, currently the only valuable database is WEBDA (http://webda.physics.muni.cz). About four million individual measurements of objects in more than 1100 Galactic star clusters are already included in the database.
Within a project, the whole population of Galactic open clusters, star subgroups, the kinematics and dynamics of the Milky Way, but also data base programming (WEBDA) can be included. Contact: Ernst Paunzen.
My research focuses on X-ray observations of matter falling onto black holes in active galactic nuclei and X-ray binaries. I study radiation coming from the closest neighbourhood to a black hole where the space-time is curved due to extremely strong gravity and also frame-dragging when the black hole is rotating. The angular momentum (spin) is very important characteristics of the black hole telling us about its formation and also about the accretion history. Black holes are not only ``eating'' the surrounding matter, large outflows (jets and winds) are observed together with the accretion. I'm keen to understand these phenomena as well. In case, you would be interested, please contact Jiri Svoboda.
Students/Researchers visiting our institute are free to continue with their own ongoing research, collaborate with the locals and/or
participate in the research at our institute depending on their interests, preferences, and duration of the stay. We offer a collaboration in
the following areas:
-disintegrating exoplanets or "exo"bodies on close orbits around their parent stars (observations, modelling) -eclipses by dusty/gaseous disks (photometry, spectroscopy, and modelling) -reflection effect and albedos of interacting binary stars -spectra, light curves, and their combination with Doppler tomography and/or interferometry of interacting binaries and exoplanets surrounded by moving circumstellar/circumplanetary material -transit timing variations and search for possible new exoplanets (photometry) -NIR photometry (dust properties, eclipses, transits, BD variability, in the future) Contact:Jan Budaj.
Members of open clusters share the same environmental conditions and have similar ages, distances, and metallicities. Gaia will provide very accurate astrometry for most of stellar members in the nearest clusters. The goal of this project is to identify eclipsing binaries over a wide range of masses at different ages focusing on the nearest and richest regions, including Taurus (~3 Myr), Upper Scorpius (10 Myr), Alpha Per (85 Myr), Pleiades (120 Myr), Praesepe (600 Myr), and the Hyades (625 Myr). We will use several telescopes and spectrographs available to the IAC, CZ, and SK institutions to identify spectroscopic binaries to measure masses and radii to constrain evolutionary models. Contact: Nicolas Lodieu.
Subdwarfs are metal-poor dwarfs which appear less luminous than their solar-metallicity counterparts due to the dearth of metals in their atmospheres. They are important tracers of the chemical enrichment history of the Galaxy and belong to the first generations of stars. The current census of cool subdwarfs remains scarce but our group has contributed significantly to the discoveries of metal-poor M and L dwarfs over the past 5 years. The goal of this project is twofold:
Binary evolution is believed to play a key role in the formation of a significant number of planetary nebulae, leading to the wide array of morphologies observed, however only a handful of binary central stars are currently known. Within this project, we will search for binary central stars in planetary nebulae using photometric and spectroscopic data from a number of sources including the ESO-NTT, ESO-VLT and multiple telescopes at the Observatorio del Roque de los Muchachos on La Palma, proceeding to characterise any new discoveries using the state-of-the-art Wilson-Devinney modelling code PHOEBE2. In case you are interested, please contact David Jones.
We offer to analyse deep, high-resolution (R~15000) optical spectrophotometric data of Galactic planetary nebulae with dual-dust chemistry. These planetary nebulae show simultaneous presence of PAHs and silicates in Spitzer spectra. Precise determinations of the C/O ratios from optical recombination lines and a detailed analysis of the chemistry of these objects would shed some light on the mechanisms that lead to the formation of these features (e.g., HBB deactivation and/or peculiar chemistry) The selected candidate would work with deep echelle UVES@VLT data and will use PyNeb, a python-based code for the analysis of emission line spectra of photoionized nebulae. If you are interested, please contact Jorge García-Rojas.
We are studying a hydrodynamical mechanism in the ejecta of Supernovae exploding within the extreme environment of Young Massive Clusters, by which the dust is produced and accumulated. The results will be published in 2018. The aim is to quantify the fraction of dust which could be injected into the circum-cluster medium before significant destruction occurs. As a follow-up study, we aim to explore the evolution of the infrared spectral energy distributions (SEDs) resultant from the emission of surviving dust grains being deposited. We will compare our theoretical SEDs, especially the near- and mid-infrared parts, with the recently observed SEDs in star clusters in M33 and other nearby galaxies. Interested, please contact Casiana Muñoz-Tuñón.
Dr. Sergio Martínez-González (AI ASCR) is currently visiting IAC since 08 May til 07 October 2018. Later, updates, results and experiences of Sergio will be shared here.
Pyroclastic Blowout: Dust Survival in Isolated versus Clustered Supernovae: Sergio Martínez-González et al.
It has now been revealed that globular clusters have multiple population which show distinct chemical compositions. This project is aimed at developing a new method to characterize the chemical content of stars globular clusters from multiband photometry. First, we propose to build a large grid of synthetic photometry taking into account various possible chemistry (C, N, O, He, Mg, Na, Al) with the MARCS model atmosphere code. The synthetic photometry will be compared with existing very high accurate HST and Johnson photometry. The MCMC algorithm is expected to be used to search for the best stellar parameters solution and will help revealing any degeneracy as well as evaluating the errors. The results will also be discussed against spatial distribution within the cluster. Interested candidates please contact Thomas Masseron.
The research group PARSEC at the IAC studies the centre of the nearest galaxies at scales of a few parsec across the entire electromagnetic spectrum. The investigation resorts to the most advanced angular resolution techniques in astronomy, interferometry, adaptive optics and speckle, to explore the region in and around the sphere of influence of the black hole. The aim is to disentangle the ultimate mechanics that power supermassive black holes.
The group investigates centres of galaxies with colliding black holes, and analyze ways by which a peaceful black hole transforms into the most powerful object of the Universe, a quasar. Interested in the subject, please contact Almudena Prieto.
We want to obtain the K-band magnitudes (and light curves, when possible) of massive asymptotic giant branch (AGB) and super-AGB star candidates in the galaxies M31 and M33 already observed in the near-IR at several epochs. The K-band light curves (variability amplitude and period) allow to discriminate between AGBs and other objects such massive red supergiants (RSG), because the most massive AGBs show periods of ~500-1000 days with variability amplitudes AK ~ 1-2 mag. These data would allow us to build a database of massive AGB stars in M31 and M33 that could be observed with telescopes of the class 8-10 meters (e.g., GTC) for detailed studies of their chemical abundances and nucleosynthesis processes. Interested, please contact Aníbal García-Hernández.
The Initial Mass Function (IMF), i.e., the characteristic distribution of stellar masses at birth in the Milky Way, has been regarded as universal and invariant over cosmic time. However recent spectroscopic studies of the integrated light of elliptical galaxies have revealed a significant deviation from the standard shape. These studies, which are based on IMF-sensitive absorption features, have shown that the IMF is no longer universal, becoming more heavier in very low mass dwarfs with increasing galaxy mass. Moreover it has been shown that the IMF is a local property that varies within massive galaxies.
It has been proposed a new theory where the IMF has to be considered on an integrated galactic scale (IGIMF). Whithin this theory the resulting distribution of stars gets less (more) enriched in dwarf stars with incresing (decreasing) Star Formation Rate with respect to the standard IMF. Moreover the metallicity also affects the IGIMF shape. This project aims at implementing and testing the IGIMF in state-of-the-art chemical evolution and stellar population models. We will carry out a detailed study of the effects of varying the IMF, through the IGIMF, on the resulting stellar population model spectra. Similarly we also will assess the impact of the IGIMF on the resulting chemical evolution and abundance ratio pattern. Finally, these models will be confronted to real galaxy spectra. People interested on this project, please contact Alejandro Vazdekis.
X-ray binary systems comprise an accreting black hole or neutron star and a mass-loosing companion. Observations performed by X-ray missions in the last decades (Rossi X-ray Timing Explorer, Chandra, XMM-Newton, Swift, etc.) provide us an opportunity to study the high-energy phenomena related to this sources such as accretion physics, binary evolution models, the theory of nuclear burning on the surface of accreting neutron stars and also the nature of the accretion - ejection processes. Using the standard X-ray software (Heasoft, SAS, CIAO, etc.), we characterise their (broad band) spectral X-ray properties, obtaining valuable information such as disc temperatures, column densities, abundances etc. If you are interested, please contact Montserrat Armas Padilla.
Natalia Shagatova is currently visiting IAC since 01 July till 31 August 2018. Later, updates, results and experiences of Natalia will be shared here.