Description
All in-person presenters will give 2 minute flash talks advertising their poster. Slides need to be sent in advance
Star systems containing three stars are common in the universe, with the triple fraction increasing with the mass of the star. Approximately 10% of solar-type stars reside in triples, while this fraction goes up to 60% for 10 stars of 10 solar masses. To fully understand the evolution of massive stars, triple evolution should be taken into account. One of the evolutionary pathways for triples...
Star clusters are ideal test beds for studying the formation and evolution of stars in diverse environments. Open clusters, being relatively sparse systems and located at a closer distance, as compared to the globular clusters, allow a more detailed analysis of their individual single and multiple stellar members. Trumpler 5 is a populous, intermediate-age (~3.4 Gyr), metal-poor ([Fe/H] ~...
We report the discovery of four blue lurkers with low- and extremely low-mass white dwarf (ELM WDs) companions in the Galactic globular cluster NGC 362 using AstroSatโs Ultra Violet Imaging Telescope (UVIT). We analyzed the multi-wavelength spectral energy distribution (SED) of FUV-bright MS stars using data from the UVIT, UVOT, GAIA EDR3, and 2.2m ESO/MPI telescopes. Two each of low-mass WDs...
Recent studies have shown, that inconsistencies in the integrated colour indices (CIs) between real star clusters and theoretical models arise due to projection of bright stars inside the apertures. Thus, in this study we determined achievable accuracy and applicability limits of the aperture photometry approach for star cluster studies. We modelled a large grid of artificial 3D star clusters...
It is well established that the frequent stellar dynamical interactions in the high-density globular cluster (GC) cores make them efficient factories of exotic objects, including millisecond pulsars (MSPs). In fact, the number of MSPs per unit mass in the Galactic GC population is some $10^3$ times larger than in the Galactic field.
As part of a large project that aims at exploiting the...
We quantify for the first time the gravitational wave (GW) phase shift appearing in the waveform
of eccentric binary black hole (BBH) mergers formed dynamically in three-body systems. For this,
we have developed a novel numerical method where we construct a reference binary, by evolving the
post-Newtonian (PN ) evolution equations backwards from a point near merger without the inclusion
of...
Using MUSE spectroscopy, we have recently revealed the existence of distinct populations of slowly and fast rotating stars in young (<2 Gyr) massive (10^5 solar masses) star clusters in the Magellanic Clouds. The differences in the stellar angular momenta naturally explain peculiar features observed in the colour-magnitude diagrams of the clusters, such as split main sequences or extended...
Star clusters play a pivotal role in understanding galaxy formation processes and evolution. However, investigations of star clusters within the disk of our Galaxy are limited due to interstellar extinction. Therefore, to understand evolution of star cluster systems in galaxy disks observations of nearby galaxies are needed. The best object for this purpose is the Andromeda (M31) galaxy, where...
Population III (Pop III) stars are ideal candidates for the formation of intermediate-mass black holes (IMBHs) because of their small mass loss and top-heavy initial mass function. If such stars were to form in star clusters, their IMBH remnants would have a higher probability of creating binary systems and eventually merge, leaving behind black holes (BHs) massive enough to be seeds of the...
To date, several planetary systems around pulsars are known. While those systems could be relics, another formation channel has recently been proposed. Massive stellar remnants (i.e., neutron stars and black holes) likely receive a natal supernova velocity kick due to the asymmetry of their birth event, propelling them through space at high speed. We study the hypothetical encounters between...
Stellar-mass black holes play a crucial role in the dynamical evolution of globular clusters. In this work we discuss a fast method to evolve star clusters with varying initial black hole contents. We use the fast model clusterBH to reproduce the evolution of globular clusters in the database of Cluster Monte Carlo (CMC) models. In particular, we reproduce the evolution of the total stellar...
Binary black hole inspirals in globular clusters occur when the binary's eccentricity surpasses a critical value, denoted as $e_{\rm GW}$. This $e_{\rm GW}$ depends mainly on the binary's masses and semi-major axis. We perform $10^7$ binary-single scattering experiments with unequal masses to identify the different channels that produce high eccentricity binaries. We determine how the cross...
Blue straggler stars (BSS) are rejuvenated core hydrogen-burning stars that are bluer and brighter than the main-sequence turnoff stars of star clusters. They are believed to have formed via binary evolution and multiple stellar interactions. BSS are among the most massive populations of star clusters and therefore experience significant gravitational drag compared to other cluster populations...
We investigated the available Gaia catalogue data (DR3) of open clusters and studied cluster distances, sizes and membership distributions in the 3D space. The dependence of distance and size on the parallax-to-distance transformation was analysed. We argue that within two kpcs, the inverse-parallax method gives results comparable to the Bayesian approach based on the exponentially decreasing...
The Hubble constant is a crucial cosmological parameter that is a measure of the rate of change of the cosmic scale factor per unit cosmic scale factor i.e. a_dot / a. There is a considerable discrepancy between the measurements of the Hubble constant from standard candle observations and those from cosmic microwave background (CMB) observations. Data from gravitational wave (GW) events can...
Gravitational Waves have proven to be an excellent tool for understanding populations of binaries. In this work, we investigate the population of White Dwarf binaries in the Milky Way. We calculate the Gravitational Wave background from these sources in the LISA sensitivity range.
We use the COMPAS population synthesis code, and investigate the dependence of the background spectrum on the ...
Most massive stars form in binary or even multiple systems. During their evolution, these binaries almost inevitably undergo a critical phase where the binary members exchange mass. It has been shown that this mass transfer plays a crucial role in shaping the evolution of both stars and is responsible for many fascinating astrophysical phenomena currently being observed, such as the formation...
During the early dynamical evolution of a dense stellar system, such as a young star-forming region, stars can be ejected as runaway stars following a close dynamical interaction. These stars are still extremely young at the time of ejection and might harbour a protoplanetary disc, which has been truncated or limited in size by the ejection encounter. Based on three runaway stars from the...
In this work, we present an understanding of the complex mechanisms that govern the evolution of orbits in the Galactic Centre. Through N-body simulations, we have gained crucial insights into the evolution of disk-like structures in the Galactic Centre. We see that post-Newtonian corrections and perturbative effects are critical in stabilizing these structures. In their absence, these...
Introduction: The gravitational encounters occurring in Globular Clusters (GCs) drive the system toward energy equipartition and trigger other dynamical processes, that still require a self-consistent theoretical description. Internal kinematics observations show a partial degree of equipartition (Libralato et al. 2018, 2019, 2022; Watkins et al. 2022), confirming N-body predictions...
Globular clusters (GCs) can be used to probe the Milky Way's accretion history, potential, and dark substructures. Additionally, GCs could provide formation pathways for nuclear star clusters and supermassive black hole seeds. A detailed understanding of GC formation and evolution is therefore necessary, so it is important to capture the relevant physics in cosmological simulations. Several...
The presence of young stellar populations in Large Magellanic Cloud cluster NGC 1783 has caught significant attention, with suggestions ranging from it being a genuine secondary stellar generation to a population of blue straggler stars or simply contamination from background stars. Thanks to multi-epoch observations with the Hubble Space Telescope, proper motions for stars within the field...
Feedback mechanisms in massive stars are thought to have important implications for the evolutionary process of star clusters. Among them, photoionization feedback is the process by which ionized photons emitted by massive stars influence subsequent star formation in the surrounding environment.
In star cluster formation simulations, ionized regions can be correctly treated using a direct...
Supermassive black holes in galactic nuclei are expected to accumulate a cusp of stellar-mass black holes around them. If the galactic nucleus evolves into an active galactic nucleus (AGN), these black holes will cross the AGN's gaseous disk twice per orbit, each time experiencing a gaseous dynamical friction force. This dynamical friction will induce alignment and circularization of the black...
Tidal disruptions of stars by massive black holes (MBHs) in dense stellar clusters may be an important channel for MBH growth. While full tidal disruption events (FTDEs) have been studied extensively, recently the focus has shifted to understanding the impact of partial tidal disruption events (PTDEs). We study MBH growth in dense star clusters through full and partial tidal disruption events...
