A5090892445- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Astronomical Observations and Instrumentation
- Superconducting Materials and Applications
- Nuclear Physics and Applications
- Toxoplasma gondii Research Studies
- Spectroscopy Techniques in Biomedical and Chemical Research
- Pulsars and Gravitational Waves Research
- Astrophysics and Star Formation Studies
- Metabolism and Genetic Disorders
- Herpesvirus Infections and Treatments
- Relativity and Gravitational Theory
- Animal Virus Infections Studies
- History and Developments in Astronomy
- Galaxies: Formation, Evolution, Phenomena
- Photocathodes and Microchannel Plates
- Mitochondrial Function and Pathology
- Particle Detector Development and Performance
- Adaptive optics and wavefront sensing
- Medical Imaging Techniques and Applications
Trinity College Dublin
2023
Kyoto University
2020-2021
Ege University
2017-2021
Context. As type Ia supernova cosmology transitions from a statistics-dominated to systematics-dominated era, it is crucial understand the remaining unexplained uncertainties that affect their luminosity, such as those stemming astrophysical biases. Type supernovae are standardisable candles whose absolute magnitude reaches scatter of typically 0.15 mag when empirical correlations with light-curve stretch and colour environmental properties accounted for. Aims. We investigate dependence...
Context. Type Ia supernova (SN Ia) cosmology studies will soon be dominated by systematic, uncertainties, rather than statistical ones. Thus, it is crucial to understand the unknown phenomena potentially affecting their luminosity that may remain, such as astrophysical biases. For accurate application in studies, SN magnitudes need standardised; namely, they must corrected for correlation with light-curve width and colour. Aims. Here, we investigate how standardisation procedure used reduce...
ı tre diagram is a key tool for addressing observational systematics, such as the Malmquist bias. As distance modulus of SNe Ia derived from fit their light curves, robust simulation framework required. In this paper, we present performances skysurvey with aim to reproduce Zwicky Transient Facility (ZTF) SN DR2, which covers first phase ZTF and ran March 2018 December 2020. The DR2 sample corresponds almost 3000 classified cosmological quality. We simulated individual curves confirm validity...
Context. The unprecedented statistics of detected Type Ia supernovae (SNe Ia) brought by the Zwicky Transient Facility (ZTF) enable us to probe impact large-scale structure (LSS) on properties these objects. Aims. goal this paper is explore possible under-dense part LSS intrinsic SALT2 light-curve SNe and uncover biases in SN analyses. Methods. With a volume-limited selection ZTF-Cosmo-DR2 overlapping with SDSS-DR7 survey footprint, we investigated distribution their regard voids galaxy...
We present ultraviolet, optical and infrared photometry spectroscopy of the type Ic superluminous supernova (SLSN) Gaia16apd (= SN 2016eay), covering its evolution from 26 d before $g$-band peak to 234.1 after peak. was followed as a part NOT Unbiased Transient Survey (NUTS). It is one closest SLSNe known ($z = 0.102\pm0.001$), with detailed ultraviolet (UV) observations spectroscopically typical SLSN, exhibiting characteristic blue early spectra O II absorption, reaches $M_{g} -21.8 \pm...
We present optical-infrared photometric and spectroscopic observations of Gaia18dvy, located in the Cygnus OB3 association at a distance 1.88 kpc. The object was noted by Gaia alerts system when its lightcurve exhibited $\gtrsim$4 mag rise 2018-2019. brightening also observable mid-infared wavelengths. infrared colors Gaia18dvy became bluer as outburst progressed. Its optical near-infrared characteristics phase are consistent with those bona fide FU Orionis-type young eruptive stars....
Identifying black holes is essential for our understanding of the development stars and can reveal novel principles physics. Gravitational microlensing provides an exceptional opportunity to examine undetectable population in Milky Way. In particular, long-lasting events are likely be associated with massive lenses, including holes. We present analysis Gaia18ajz event reported by Gaia Science Alerts system. a long-timescale exhibiting features indicative annual parallax effect. Our objective...
Type Ia supernovae (SNe Ia) are a key probe in modern cosmology, as they can be used to measure luminosity distances at gigaparsec scales. Models of their light-curves project heterogeneous observed data onto common basis for analysis. The SALT model currently SN cosmology describes SNe having two sources variability, accounted by color parameter c, and "stretch parameter" x1. We extend the include an additional we label x2, investigate cosmological impact unaddressed light-curve...
Gaia16aye was a binary microlensing event discovered in the direction towards northern Galactic disc and one of first events detected alerted to by Gaia space mission. Its light curve exhibited five distinct brightening episodes, reaching up I=12 mag, it covered great detail with almost 25,000 data points gathered network telescopes. We present photometric spectroscopic follow-up covering 500 days evolution. employed full Keplerian orbit model combined motion Earth around Sun reproduce...
In this study, we explore the characteristics of `low-mass' (log( ≤ 8) and `intermediate-mass' (8 $<$ log( 10) host galaxies Type Ia supernovae (SNe Ia) from second data release (DR2) Zwicky Transient Facility survey. We investigated their correlations with different sub-types SNe Ia. used photospheric velocities measured feature, SALT2 light-curve stretch (x_1), host-galaxy properties to re-investigate existing relationship between galaxy mass velocities. also sub-type preferences for...
The Zwicky Transient Facility SN Ia Data Release 2 provides a perfect opportunity to perform thorough search for and subsequent analysis of high-velocity features (HVFs) in the pre-peak regime. source such remains unclear, but potential origins include circumstellar material, as well enhancements abundances or densities intrinsic supernova (SN) ejecta. Therefore, they may provide clues elusive progenitor explosion scenarios Type SNe (SNe Ia). We employed Markov chain Monte Carlo fitting...
We report the analysis of a planetary microlensing event AT2021uey. The was observed outside Galactic bulge and alerted both space-( Gaia ) ground-based (ZTF ASAS-SN) surveys. From data, we find that lens system is located at distance ∼1 kpc comprises an M-dwarf host star about half solar mass, orbited by Jupiter-like planet beyond snowline. source could be metal-poor giant in halo according to spectral analyses modelling. Hence, AT2021uey unique example binary-lens offered disc-halo...
Abstract T CrB is a symbiotic recurrent nova that last erupted in 1946. Given its recurrence timescale of approximately 80 years, the next outburst eagerly anticipated by astronomical community. In this work, we analyse optical light curves CrB, comparing recent photometric evolution with historical data to evaluate potential predictive indicators eruptions. Although ‘super-active’ phases preceding both 1946 and eruptions are strikingly similar, subsequent behaviour differs. We find decline...
Abstract We present optical observations of the Type Ia supernova (SN) 2019ein, starting two days after estimated explosion date. The spectra and light curves show that SN 2019ein belongs to a high-velocity (HV) broad-line group with relatively rapid decline in (Δ m 15 ( B ) = 1.36 ± 0.02 mag) short rise time (15.37 0.55 days). Si ii λ 6355 velocity, associated photospheric component but not detached feature, reached ∼20,000 km s −1 12 before -band maximum. line however, decreased very...
The nature of the progenitor systems and explosion mechanisms that give rise to Type Ia supernovae (SNe Ia) are still debated. interaction signature circumstellar material (CSM) being swept up by expanding ejecta can constrain type system from which it was ejected. Most previous studies have focused on finding CSM ejected shortly before SN residing close site, resulting in short delay times until starts. We use a sample 3627 SNe Zwicky Transient Facility discovered between 2018 2020 search...
Understanding the impact of astrophysical environment on Type Ia supernova (SN Ia) properties is crucial to minimize systematic uncertainties in cosmological analyses based this probe. We investigate dependence SN SALT2.4 light-curve stretch distance from their nearest galaxy cluster study potential effect intracluster medium (ICM) intrinsic Ia. used largest sample date and cross-matched it with existing X-ray, Sunyaev-Zel'dovich, optical catalogs order relation between detected each modeled...
The Zwicky Transient Facility SN Ia Data Release 2 (ZTF DR2) contains more than 3,000 Type supernovae (SNe Ia), providing the largest homogeneous low-redshift sample of SNe Ia. Having at least one spectrum per event, this data collection is ideal for large-scale statistical studies photometric, spectroscopic and host-galaxy properties Ia, particularly rarer `peculiar' sub-classes. In paper we first present method developed to spectroscopically classify in sample, techniques used model their...
We present comprehensive spectroscopic and photometric analyses of the intermediate luminosity Type Iax supernova (SN Iax) 2019muj based on multi-band datasets observed through framework OISTER target-of-opportunity program. SN exhibits almost identical characteristics with subluminous SNe 2008ha 2010ae in terms spectral features light curve evolution at early phase, except for peak luminosity. The long-term observations unveil flattening curves late time as seen a luminous 2014dt. This can...
Identifying black holes is essential for comprehending the development of stars and uncovering novel principles physics. Gravitational microlensing provides an exceptional opportunity to examine undetectable population in Milky Way. In particular, long-lasting events are likely be associated with massive lenses, including holes. We present analysis Gaia18ajz event, reported by Gaia Science Alerts system, which has exhibited a long timescale features indicative annual parallax effect. Our...
As Type Ia supernova cosmology transitions from a statistics dominated to systematics era, it is crucial understand leftover unexplained uncertainties affecting their luminosity, such as the ones stemming astrophysical biases. Indeed, SNe are standardisable candles, whose absolute magnitude reach 0.15~mag scatter once empirical correlations with lightcurve stretch and colour environment accounted for. In this paper, we investigate how standardisation process of depends on environment,...
Context. Type Ia supernova (SNIa) are excellent probes of local distance and the growing sample sizes SNIa have driven an increased propensity to study associated systematic uncertainties improve standardisation methods in preparation for next generation cosmological surveys into dark energy equation state, w . Aims. We aim probe potential change parameter, c , with redshift host-galaxy supernova. Improving brightness measurements will require relationship between host be accounted for. In...
Type Ia supernova (SN Ia) light curves have a secondary maximum that exists in the $r$, $i$, and near-infrared filters. The is relatively weak $r$ band, but holds advantage it accessible, even at high redshift. We used Gaussian process fitting to parameterise of 893 SNe from Zwicky Transient Facility's (ZTF) second data release (DR2), we were able extract information about timing strength maximum. found $>5 correlations between curve dec rate ($ (g)$) band. Whilst $i$ band also correlated...
We present the first homogeneous release of several thousand Type Ia supernovae (SNe Ia), all having spectroscopic classification, and redshifts for half sample. This release, named "DR2", contains 3628 nearby (z < 0.3) SNe discovered, followed classified by Zwicky Transient Facility survey between March 2018 December 2020. Of these, 3000 have good-to-excellent sampling 2667 pass standard cosmology light-curve quality cuts. is thus largest SN to date, increasing an order magnitude number...
Accurate classification of transients obtained from spectroscopic data are important to understand their nature and discover new classes astronomical objects. For supernovae (SNe), SNID, NGSF (a Python version SuperFit), DASH widely used in the community. Each tool provides its own metric help determine classification, such as rlap chi2/dof NGSF, Probability DASH. However, we do not know how accurate these tools are, they have been tested with a large homogeneous dataset. Thus, this work,...