Opazovanja plimskih raztrganj zvezd z Velikim sinoptičnim pregledovalnim teleskopomKatja Bricman
, Andreja Gomboc
, 2018, published scientific conference contribution abstract
Abstract: Plimska raztrganja zvezd so redki dogodki, do katerih pride, ko zvezdo zanese v bližino masivne črne luknje v središču galaksije, kjer jo močne plimske sile črne luknje raztrgajo. Blišč svetlobe, ki ob tem nastane, lahko opazujemo do kozmoloških razdalj. Veliki sinoptični pregledovalni teleskop (Large Synoptic Survey Telescope - LSST), ki je v gradnji v Čilu, bo ponavljajoče opazoval 18.000 kvadratnih stopinj južnega neba v šestih optičnih filtrih do limitne magnitude 24,5 v r filtru. Omogočal bo opazovanja 20 milijard zvezd in 20 milijard galaksij, s primerjavo starih in novih posnetkov pa bo zaznal spremembe na nebu oziroma tranzientne izvore ter bo tako odlično orodje za iskanje plimskih raztrganj zvezd. Z uporabo simulacijskega orodja LSST smo simulirali opazovanja plimskih raztrganj zvezd na majhnem delu neba velikosti 20,25 kvadratnih stopinj. S pomočjo simuliranih svetlobnih krivulj smo ocenili število plimskih raztrganj zvezd, ki jih bo teleskop odkril v desetih letih delovanja.
Found in: osebi
Keywords: Plimska raztrganja zvezd, pregledovalni teleskopi
Published: 10.05.2021; Views: 515; Downloads: 0
Studying TDEs in the era of LSSTKatja Bricman
, Andreja Gomboc
, 2019, published scientific conference contribution abstract
Abstract: The observing strategy with continuous scanning and large sky coverage of the upcoming ground-based Large Synoptic Survey Telescope (LSST) will make it a perfect tool in search of rare transients, such as Tidal Disruption Events (TDEs). Bright optical flares resulting from tidal disruption of stars by their host supermassive black hole (SMBH) can provide us with important information about the mass of the SMBH involved in the disruption and thus enable the study of quiescent SMBHs, which represent a large majority of SMBHs found in centres of galaxies. These types of transients are extremely rare, with only about few tens of candidates discovered so far. It is expected that the LSST will provide a large sample of new TDE light curves. Here we present simulations of TDE observations using an end-to-end LSST simulation framework. Based on the analysis of simulated light curves we estimate the number of TDEs with good quality light curves the LSST is expected to discover in 10 years of observations. In addition, we investigate whether TDEs observed by the LSST could be used to probe the SMBH mass distribution in the universe.
Found in: osebi
Keywords: Tidal Disruption Events, sky surveys
Published: 04.01.2021; Views: 818; Downloads: 31
Tidal Disruption Events seen through the eyes of Vera C. Rubin ObservatoryKatja Bučar Bricman
, 2021, doctoral dissertation
Abstract: Tidal Disruption Events (TDEs) are rare transients, which are considered to be promising tools in probing supermassive black holes (SMBHs) and their environments in quiescent galaxies, accretion physics, and jet formation mechanisms. The majority of $\approx$ 60 detected TDEs has been discovered with large field of view time-domain surveys in the last two decades. Currently, about 10 TDEs are discovered per year, and we expect this number will increase largely once the Legacy Survey of Space and Time (LSST) at Vera C. Rubin Observatory begins its observations.
In this work we demonstrate and explore the capabilities of the LSST to study TDEs. To begin with, we simulate LSST observations of TDEs over $10$ years of survey duration by including realistic SED models from MOSFiT into the simulation framework of the LSST. SEDs are then converted into observed fluxes and light curves are simulated with the LSST observing strategy minion_1016. Simulated observations are used to estimate the number of TDEs the LSST is expected to observe and to assess the possibility of probing the SMBH mass distribution in the Universe with the observed TDE sample. We find that the LSST has a potential of observing ~1000 TDEs per year, the exact number depending on the SMBH mass distribution and the adopted observing strategy. In spite of this large number, we find that probing the SMBH mass distribution with LSST observed TDEs will not be straightforward, especially at the low-mass end. This is largely attributed to the fact that TDEs caused by low-mass black holes ($\le 10^6 M_\odot$) are less luminous and shorter than TDEs by heavier SMBHs ($> 10^6 M_\odot$), and the probability of observationally missing them with LSST is higher.
Second, we built a MAF TDE metric for photometric identification of TDEs based on LSST data. We use the metric to evaluate the performance of different proposed survey strategies in identifying TDEs with pre-defined identification requirements. Since TDEs are blue in color for months after peak light, which separates them well from SNe and AGN, we include u-band observations as one of the criteria for a positive identification. We find that the number of identified TDEs strongly depends of the observing strategy and the number of u-band visits to a given field in the sky. Observing strategies with a larger number of u-band observations perform significantly better. For these strategies up to 10% of LSST observed TDEs satisfy the identification requirements.
Found in: osebi
Keywords: Ground-based ultraviolet, optical and infrared telescopes
Astronomical catalogs, atlases, sky surveys, databases, retrieval systems, archives, Black holes, Galactic nuclei (including black holes), circumnuclear matter, and bulges, Infall, accretion, and accretion disks
Published: 03.01.2022; Views: 110; Downloads: 4
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