Tidal Disruption Events seen through the eyes of Vera C. Rubin ObservatoryKatja Bučar Bricman
, 2021, doktorska disertacija
Opis: 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.
Ključne besede: 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
Objavljeno v RUNG: 03.01.2022; Ogledov: 2116; Prenosov: 46
Celotno besedilo (124,61 MB)
Opazovanja plimskih raztrganj zvezd z Velikim sinoptičnim pregledovalnim teleskopomKatja Bricman
, A. Gomboc
, 2018, objavljeni povzetek znanstvenega prispevka na konferenci
Opis: 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.
Ključne besede: Plimska raztrganja zvezd, pregledovalni teleskopi
Objavljeno v RUNG: 10.05.2021; Ogledov: 1658; Prenosov: 0
Observing TDEs in the era of LSSTKatja Bricman
, 2020, objavljeni povzetek znanstvenega prispevka na konferenci
Opis: The upcoming Large Synoptic Survey Telescope (LSST) will observe ~18000 square degrees of the Southern sky and is expected to discover thousands of transients every night due to its large coverage of the sky and its observing strategy. Being an exceptional transient hunter, we expect the LSST to increase the current observed sample of Tidal Disruption Events (TDEs) by a factor of ~1000 in 10 years of survey duration. TDEs are one of the most promising phenomena in the study of dormant supermassive black holes (SMBHs) in the Universe, and if their observed optical light curves are sampled frequently enough, TDEs can serve as indicators of SMBH mass. We present our simulations of TDE observations with the LSST, the resulting SMBH mass distributions of observed TDEs, and the efficiency of different proposed observing strategies of the LSST in finding these rare transients.
Ključne besede: Tidal Disruption Events, Supermassive black holes, sky surveys
Objavljeno v RUNG: 04.01.2021; Ogledov: 2016; Prenosov: 0
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