A5110104643- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Gaussian Processes and Bayesian Inference
- Bayesian Methods and Mixture Models
- Gamma-ray bursts and supernovae
- Sports Analytics and Performance
- Cosmology and Gravitation Theories
- Markov Chains and Monte Carlo Methods
- Scientific Research and Discoveries
- Pulsars and Gravitational Waves Research
- Astrophysics and Star Formation Studies
- Astrophysics and Cosmic Phenomena
- Statistical Methods and Bayesian Inference
- Adaptive optics and wavefront sensing
- Radio Astronomy Observations and Technology
- Statistical Mechanics and Entropy
- Sports Performance and Training
- Astro and Planetary Science
- Underwater Acoustics Research
- Sport and Mega-Event Impacts
- Forest ecology and management
- Transportation Planning and Optimization
- Economic and Environmental Valuation
University of Auckland
2015-2025
Statistics New Zealand
2017
University of California, Santa Barbara
2009-2012
The University of Sydney
2005-2008
UNSW Sydney
2008
We present dynamical modelling of the broad-line region (BLR) for a sample five Seyfert 1 galaxies using reverberation mapping data taken by Lick AGN Monitoring Project in 2008. By continuum light curve and Hβ line profiles directly, we are able to constrain geometry kinematics BLR make measurement black hole mass that does not depend upon virial factor, f, needed traditional analysis. find is generally thick disc viewed close face-on. While emission found come preferentially from far side...
Bayesian inference methods rely on numerical algorithms for both model selection and parameter inference. In general, these require a high computational effort to yield reliable estimates. One of the major challenges in phylogenetics is estimation marginal likelihood. This quantity commonly used comparing different evolutionary models, but its calculation, even simple incurs cost. Another interesting challenge relates posterior distribution. Often, long Markov chains are required get...
In the Spring of 2011 we carried out a 2.5 month reverberation mapping campaign using 3 m Shane telescope at Lick Observatory, monitoring 15 low-redshift Seyfert 1 galaxies. This paper describes observations, reductions and measurements, data products from spectroscopic campaign. The reduced spectra were fitted with multicomponent model in order to isolate contributions various continuum emission-line components. We present light curves broad emission lines active galactic nucleus (AGN)...
The prominent broad Fe ii emission blends in the spectra of active galactic nuclei have been shown to vary response continuum variations, but past attempts measure reverberation lag time optical lines met with only limited success. Here we report detection two Seyfert 1 galaxies, NGC 4593 and Mrk 1511, based on data from a program carried out at Lick Observatory Spring 2011. Light curves for including Hβ were measured by applying fitting routine decompose into several emission-line...
We present a general method to analyze reverberation mapping data that provides both estimates for the black hole mass and geometry dynamics of broad line region (BLR) in active galactic nuclei (AGN). Our directly infers spatial velocity distribution BLR from data, allowing us easily derive velocity-resolved transfer function self-consistent estimate without virial coefficient. obtain reasonable uncertainties model parameters by implementing Markov Chain Monte Carlo algorithm using formalism...
We introduce a general Monte Carlo method based on Nested Sampling (NS), for sampling complex probability distributions and estimating the normalising constant. The uses one or more particles, which explore mixture of nested distributions, each successive distribution occupying ∼e −1 times enclosed prior mass previous distribution. While NS technically requires independent generation Markov Chain (MCMC) exploration fits naturally into this technique. illustrate new test problem find that it...
We present an improved and expanded simply parameterized phenomenological model of the broad line region (BLR) in active galactic nuclei (AGN) for modeling reverberation mapping data. By data directly, we can constrain geometry dynamics BLR measure black hole mass without relying on normalization factor needed traditional analysis. For realistic simulated datasets high-quality, recover to $0.05-0.25$ dex uncertainty distinguish between dominated by elliptical orbits inflowing gas. While...
The Cosmological Principle, that the Universe is homogeneous and isotropic on sufficiently large scales, underpins standard model of cosmology. However, a recent analysis 1.36 million infrared-selected quasars has identified significant tension in amplitude number-count dipole compared to derived from CMB, thus challenging Principle. Here we present Bayesian same quasar sample, testing various hypotheses using evidence. We find unambiguous evidence for presence distribution with direction...
We have observed oscillations in the nearby G2 subgiant star beta Hyi using high-precision velocity observations obtained over more than a week with HARPS and UCLES spectrographs. The oscillation frequencies show regular comb structure, as expected for solar-like oscillations, but several l=1 modes being strongly affected by avoided crossings. data, combined those we five years earlier, allow us to identify 28 modes. By scaling large frequency separation from Sun, measure mean density of an...
The Lick AGN Monitoring Project 2011 observing campaign was carried out over the course of 11 weeks in Spring 2011. Here we present first results from this program, a measurement broad-line reverberation lag Seyfert 1 galaxy Mrk 50. Combining our data with supplemental observations obtained prior to start main campaign, dataset covers total duration 4.5 months. During time, 50 highly variable, exhibiting maximum variability amplitude factor 4 U-band continuum and 2 H-beta line. Using...
We construct a fully self-consistent mass model for the lens galaxy J2141 at z=0.14, and use it to improve on previous studies by modelling its gravitational lensing effect, gas rotation curve stellar kinematics simultaneously. adopt very flexible axisymmetric constituted generalized NFW dark matter halo distribution obtained deprojecting MGE fit high-resolution K'-band LGSAO imaging data of galaxy, with (spatially constant) M/L ratio as free parameter. solving anisotropic Jeans equations....
We present dynamical modeling of the broad line region (BLR) in Seyfert 1 galaxy Mrk 50 using reverberation mapping data taken as part Lick AGN Monitoring Project (LAMP) 2011. model directly, constraining geometry and kinematics BLR, well deriving a black hole mass estimate that does not depend on normalizing factor or virial coefficient. find BLR is nearly face-on thick disk, with mean radius 9.6(+1.2,-0.9) light days, width 6.9(+1.2,-1.1) disk opening angle 25\pm10 degrees above plane....
We present models of the H$\beta$-emitting broad-line region (BLR) in seven Seyfert 1 galaxies from Lick AGN (Active Galactic Nucleus) Monitoring Project 2011 sample, drawing inferences on BLR structure and dynamics as well mass central supermassive black hole. find that is generally a thick disk, viewed close to face-on, with preferential emission back toward ionizing source. The our sample range near-circular elliptical orbits inflowing or outflowing trajectories. measure hole masses...
Recent work has suggested that the stellar initial mass function (IMF) is not universal, but rather correlated with galaxy mass, velocity dispersion or morphological type. In this paper, we investigate variations of IMF within individual galaxies. For purpose, use strong lensing and gas kinematics to measure independently normalization bulge disc components a sample five massive spiral galaxies substantial taken from Sloan WFC Edge-on Late-type Lens Survey (SWELLS). We find masses bulges are...
The degeneracy among the disk, bulge and halo contributions to galaxy rotation curves prevents an understanding of distribution baryons dark matter in disk galaxies. In attempt break this degeneracy, we present analysis spiral strong gravitational lens SDSS J2141-0001, discovered as part SLACS survey. We new Hubble Space Telescope multicolor imaging, gas stellar kinematics data derived from long-slit spectroscopy, K-band LGS adaptive optics both Keck telescopes. model a sum concentric...
The relative contribution of baryons and dark matter to the inner regions spiral galaxies provides critical clues their formation evolution, but it is generally difficult determine. For that are strong gravitational lenses, however, combination lensing kinematic observations can be used break disk-halo degeneracy. In turn, such data constrain fundamental parameters as i) mass density profile slope axis ratio halo, by comparison with matter-only numerical simulations modifications imposed...
Supermassive black holes are believed to be ubiquitous at the centers of galaxies. Measuring their masses is extremely challenging yet essential for understanding role in formation and evolution cosmic structure. We present a direct measurement mass hole an active galactic nucleus (Arp 151) based on motion gas responsible broad emission lines. By analyzing modeling spectroscopic photometric time series, we find that well described by disk or torus with average radius 3.99 +- 1.25 light days...
Inferring the number of planets N in an exoplanetary system from radial velocity (RV) data is a challenging task. Recently, it has become clear that RV can contain periodic signals due to stellar activity, which be difficult distinguish planetary signals. However, even doing inference under given set simplifying assumptions (e.g. no activity) difficult. It common for posterior distribution planet parameters, such as orbital periods, multimodal and have other awkward features. In addition,...
We have modeled the velocity-resolved reverberation response of H\b{eta} broad emission line in nine Seyfert 1 galaxies from Lick Active Galactic Nucleus (AGN) Monitioring Project 2016 sample, drawing inferences on geometry and structure low-ionization broad-line region (BLR) mass central supermassive black hole. Overall, we find that BLR is generally a thick disk viewed at low to moderate inclination angles. combine our sample with prior studies investigate line-profile shape dependence,...
We present high-resolution (0.3") Very Large Array (VLA) imaging of the molecular gas in host galaxy high redshift quasar PSS J2322+1944 (z=4.12). These observations confirm that (CO) this is lensed into a full Einstein ring, and reveal internal dynamics system. The ring has diameter ~1.5", thus sampled over ~20 resolution elements by our observations. Through model-based lens inversion, we recover velocity gradient reservoir J2322+1944. configuration enables us to zoom on emission resolve...
We present gravitational lens models for 20 strong systems observed as part of the Sloan WFC Edge-on Late-type Lens Survey (SWELLS) project. Fifteen lenses are taken from paper I while five newly discovered systems. The galaxy-galaxy where foreground deflector has an inclined disc, with a wide range morphological types, late-type spiral to lenticular. For each system, we compare total mass inside critical curve inferred modelling stellar population synthesis (SPS) models, computing fraction...
In probabilistic (Bayesian) inferences, we typically want to compute properties of the posterior distribution, describing knowledge unknown quantities in context a particular dataset and assumed prior information. The marginal likelihood, also known as