A5005643680- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Botany, Ecology, and Taxonomy Studies
- Sesquiterpenes and Asteraceae Studies
- Botany and Plant Ecology Studies
- Nuclear Physics and Applications
- Galaxies: Formation, Evolution, Phenomena
- Plant Toxicity and Pharmacological Properties
- Plant Diversity and Evolution
- Particle Accelerators and Free-Electron Lasers
- Plant Ecology and Taxonomy Studies
- Mediterranean and Iberian flora and fauna
- Astrophysics and Cosmic Phenomena
- Plant Taxonomy and Phylogenetics
- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Biological Control of Invasive Species
- Stellar, planetary, and galactic studies
- Chromosomal and Genetic Variations
- Astrophysics and Star Formation Studies
- Spectroscopy Techniques in Biomedical and Chemical Research
- Pulsars and Gravitational Waves Research
- Cardiovascular Disease and Adiposity
- Spectroscopy and Laser Applications
- Cardiac Imaging and Diagnostics
Royal Observatory
2019-2023
University of Edinburgh
2019-2023
University of Sheffield
2015-2021
Isaac Newton Group
2017
Fishwell Consulting (Australia)
2010
Government of the Northern Territory
2004
Australian National Herbarium
1986-1996
Chiba University
1996
Kyushu University
1996
Kobe University
1992-1996
Stars that interact with supermassive black holes (SMBHs) can either be completely or partially destroyed by tides. In a partial tidal disruption event (TDE) the high-density core of star remains intact, and low-density, outer envelope is stripped feeds luminous accretion episode. The TDE AT2018fyk, an inferred hole mass $10^{7.7\pm0.4}$ M$_{\odot}$, experienced extreme dimming at X-ray (factor $>$6000) UV $\sim$15) wavelengths $\sim$500--600 days after discovery. Here we report on...
At 66 Mpc, AT2019qiz is the closest optical tidal disruption event (TDE) to date, with a luminosity intermediate between bulk of population and iPTF16fnl. Its proximity allowed very early detection triggering multiwavelength spectroscopic follow-up well before maximum light. The velocity dispersion host galaxy fits TDE light curve indicate black hole mass $\approx 10^6$ M$_\odot$, disrupting star 1$ M$_\odot$. Comprehensive UV, X-ray data shows that emission dominated by an outflow,...
Abstract On 2019 April 25.346 and 26.640 UT the Laser Interferometer Gravitational-Wave Observatory (LIGO) Virgo gravitational-wave (GW) observatory announced detection of first candidate events in Observing Run 3 that contained at least one neutron star (NS). S190425z is a likely binary (BNS) merger d L = 156 ± 41 Mpc, while S190426c possibly NS–black hole (BH) ever detected, 377 100 although with marginal statistical significance. Here we report our optical follow-up observations for both...
ABSTRACT With the sample of observed tidal disruption events (TDEs) now reaching several tens, distinct spectroscopic classes have emerged: TDEs with only hydrogen lines (TDE-H), helium (TDE-He), or in combination He ii and often N iii/O iii (TDE-H + He). Here, we model light curves 32 optically bright using Modular Open Source Fitter for Transients (mosfit) to estimate physical orbital properties, look statistical differences between classes. For all types, find a shallow distribution star...
Abstract We present panchromatic observations and modeling of the Calcium-rich supernova (SN) 2019ehk in star-forming galaxy M100 ( d ≈ 16.2 Mpc) starting 10 hr after explosion continuing for ∼300 days. SN shows a double-peaked optical light curve peaking at t = 3 15 The first peak is coincident with luminous, rapidly decaying Swift-XRT–discovered X-ray emission <?CDATA ${L}_{{\rm{x}}}\approx {10}^{41}\,\mathrm{erg}\,{{\rm{s}}}^{-1}$?> days; L x ∝ −3 ), Shane/Kast spectral detection narrow H...
We present and analyse a new tidal disruption event (TDE), AT2017eqx at redshift z=0.1089, discovered by Pan-STARRS ATLAS. The position of the transient is consistent with nucleus its host galaxy; it peaks luminosity $L \approx 10^{44}$ erg s$^{-1}$; spectrum shows persistent blackbody temperature $T \gtrsim 20,000$ K broad H I He II emission. lines are initially centered zero velocity, but 100 days disappear while develops blueshift $\gtrsim 5,000$ km s$^{-1}$. Both early- late-time...
We present results from spectroscopic observations of AT 2018hyz, a transient discovered by the ASAS-SN survey at an absolute magnitude $M_V\sim -20.2$ mag, in nucleus quiescent galaxy with strong Balmer absorption lines. 2018hyz shows blue spectral continuum and broad emission lines, consistent previous TDE candidates. High cadence follow-up spectra show lines He I early spectra, II making appearance after $\sim70-100$ days. The evolve smooth profile, through boxy, asymmetric double-peaked...
Spectroscopically, TDEs are characterized by broad ( 10$^{4}$ km/s) emission lines and show large diversity as well different line profiles. After carefully consistently performing a series of data reduction tasks including host galaxy light subtraction, we present here the first detailed, spectroscopic population study 16 optical/UV TDEs. We report time lag between peaks optical light-curves peak luminosity H$\alpha$ spanning 7 - 45 days. If interpreted light-echoes, these lags correspond...
ABSTRACT We present the results of a large multiwavelength follow-up campaign tidal disruption event (TDE) AT 2019dsg, focusing on low to high resolution optical spectroscopy, X-ray, and radio observations. The galaxy hosts super massive black hole mass $\rm (5.4\pm 3.2)\times 10^6\, M_\odot$ careful analysis finds no evidence for presence an active galactic nucleus, instead TDE host shows narrow emission lines that likely arise from star formation activity. transient is luminous in X-rays,...
Tidal disruption events (TDEs) occur when a star gets torn apart by supermassive black hole as it crosses its tidal radius. We present late-time optical and X-ray observations of the nuclear transient AT2019qiz, which showed typical signs an optical-UV class commonly believed to be TDEs. Optical spectra were obtained 428, 481 828 rest-frame days after lightcurve peak, UV/X-ray observation coincided with later spectrum. The show strong coronal emission lines, including [Fe VII], X], XI] XIV]....
AT 2018hyz (=ASASSN-18zj) is a tidal disruption event (TDE) located in the nucleus of quiescent E+A galaxy at redshift $z = 0.04573$, first detected by All-Sky Automated Survey for Supernovae (ASAS-SN). We present optical+UV photometry transient, as well an X-ray spectrum and radio upper limits. The bolometric light curve comparable to other known TDEs declines rate consistent with $t^{-5/3}$ early times, emitting total radiated energy $E 9\times10^{50}$ erg. An excess bump appears UV about...
Aims. The modelling of spectroscopic observations tidal disruption events (TDEs) to date suggests that the newly formed accretion disks are mostly quasi-circular. In this work we study transient event AT 2020zso, hosted by an active galactic nucleus (AGN; as inferred from narrow emission line diagnostics), with aim characterising properties its flow. Methods. We classify 2020zso a TDE based on blackbody evolution UV/optical photometric and spectral content evolution. identify transient,...
Fast outflows of gas, driven by the interaction between radio jets and interstellar medium (ISM) host galaxy, are being observed in an increasing number galaxies. One such example is nearby galaxy 3C 293. In this paper we present integral field unit observations taken with OASIS on William Herschel Telescope, enabling us to map spatial extent ionized gas across central regions galaxy. The jet-driven outflow 293 detected along inner lobes a mass rate ranging from ∼0.05 0.17 M⊙ yr−1 (in gas)...
Pollen-ovule ratios (P/O's) were used to determine the breeding systems of 24 species in 13 genera subtribe Gnaphaliinae (Compositae: Inuleae).In many cases where P/O's determined for 3 or more widely separated populations within a P/O values very uniform and readily classed as either outbreeders (P/O's = c.1,500-6, 000) inbreeders c.40-350).P/O variation between is discussed.Changes from outbreeding inbreeding recognized some closely related taxa Actinobole, Angianthus, Blennospora,...
Chromosome number determinations from 152 collections representing 42 genera and 106 species of the Australian Gnaphalieae Plucheeae are reported. The chromosome numbers 75 these have not been previously counted or differ those reported for species. documented first time 14 genera: Argyroglottis (n = 12), Cephalosorus (2n 24), Decazesia 14), Dielitzia 26), Eriochlamys Erymophyllum 11 Gilruthia 13), Leucochrysum 9), Myriocephalus s. str. 14, 2n Polycalymma Pterocaulon 10), Pterochaeta...
Abstract Interaction-powered supernovae (SNe) explode within an optically thick circumstellar medium (CSM) that could be ejected during eruptive events. To identify and characterize such pre-explosion outbursts, we produce forced-photometry light curves for 196 interacting SNe, mostly of Type IIn, detected by the Zwicky Transient Facility between early 2018 2020 June. Extensive tests demonstrate only expect a few false detections among 70,000 analyzed images after applying quality cuts bias...
Chromosome number determinations from 200 populations attributed to 99 species or infraspecific taxa of ten genera are presented in Table I.They inelude the first substantiated reports for Brachyscome glandulosa (2n = 36), B. muelleroides (n 3), obovata 18), petrophila tatei 9), ErodiophyUum elderi 16), Miniiria gardneri {n M. integerrima Olearia astrotricha O. ferresii imbricata plucheacea raimilosa xerophila Vittadinia cuneata V. gracilis muelleri (« pterochaeta piistulata 9) and sulcata...
One-opposition near-Earth asteroids (NEAs) are growing in number, and they must be recovered to prevent loss mismatch risk, improve their orbits, as likely too faint for detection shallow surveys at future apparitions. We aimed recover more than half of the one-opposition NEAs recommended observations by Minor Planet Center (MPC) using Isaac Newton Telescope (INT) soft-override mode some fractions available D-nights. During about 130 hours total between 2013 2016, we targeted 368 NEAs, among...
Angianthus Wendl.(sensu Bentham, 1867) has been revised.Eight genera, Cephalosorus A. Gray (monotypic), Chrysocoryne Endi.(6 species), Dithyrostegia Epitriche Turcz.{monoiypic), Hyalochlamys K. Muell.(monotypic), Pogo/io/ep/^Steetz (6 or 7 species) and Siloxerus Labill.(3 are reinstated.Three species with uncertain affinities