A5066337688- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Galaxies: Formation, Evolution, Phenomena
- CCD and CMOS Imaging Sensors
- Neutrino Physics Research
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Time Series Analysis and Forecasting
- Advanced Optical Sensing Technologies
- Radiation Detection and Scintillator Technologies
- Particle Detector Development and Performance
- Solar and Space Plasma Dynamics
- Adaptive optics and wavefront sensing
- Infrared Target Detection Methodologies
- Radio Astronomy Observations and Technology
- Advanced Vision and Imaging
- Integrated Circuits and Semiconductor Failure Analysis
- Dental Radiography and Imaging
- Spectroscopy Techniques in Biomedical and Chemical Research
- Silicon and Solar Cell Technologies
- Astro and Planetary Science
- Ocular and Laser Science Research
Lawrence Berkeley National Laboratory
2015-2023
University of California, Berkeley
2015-2023
City University of Seattle
2019-2023
University of Washington
2019-2023
Seattle University
2022
Lawrence Livermore National Laboratory
2020
TRIUMF
2011-2017
University of British Columbia
2012
Previously we used the Nearby Supernova Factory sample to show that Type Ia supernovae (SNe Ia) having locally star-forming environments are dimmer than SNe passive environments. Here use Constitution together with host galaxy data from GALEX independently confirm result. The effect is seen using both SALT2 and MLCS2k2 lightcurve fitting standardization methods, brightness differences of 0.094 ± 0.037 mag for 0.155 0.041 RV = 2.5. When combined our previous measurement 0.025 SALT2. If ratio...
As part of an on-going effort to identify, understand and correct for astrophysics biases in the standardization Type Ia supernovae (SNIa) cosmology, we have statistically classified a large sample nearby SNeIa into those located predominantly younger or older environments. This classification is based on specific star formation rate measured within projected distance 1kpc from each SN location (LsSFR). important refinement compared using local directly as it provides normalization relative...
Abstract Upcoming astronomical surveys such as the Large Synoptic Survey Telescope (LSST) will rely on photometric classification to identify majority of transients and variables that they discover. We present a set techniques for can be applied even when training spectroscopically confirmed objects is heavily biased toward bright, low-redshift objects. Using Gaussian process regression model arbitrary light curves in all bands simultaneously, we “augment” by generating new versions original...
While recent supernova cosmology research has benefited from improved measurements, current analysis approaches are not statistically optimal and will prove insufficient for future surveys. This paper discusses the limitations of cosmological analyses in treating outliers, selection effects, shape- color-standardization relations, unexplained dispersion, heterogeneous observations. We present a new Bayesian framework, called UNITY (Unified Nonlinear Inference Type-Ia cosmologY), that...
Type Ia supernova cosmology depends on the ability to fit and standardize observations of magnitudes with an empirical model. We present here a series new models Supernova spectral time that capture greater amount diversity than possible are currently customary. These entitled SuperNova Empirical MOdels (\textsc{SNEMO}\footnote{https://snfactory.lbl.gov/snemo}). The constructed using spectrophotometric from $172$ individual supernovae Nearby Factory, comprising more $2000$ spectra. Using...
We present ALMA CO (2-1) detections in 11 gas-rich cluster galaxies at z~1.6, constituting the largest sample of molecular gas measurements z>1.5 clusters to date. The observations span three galaxy clusters, derived from Spitzer Adaptation Red-sequence Cluster Survey. augment >5sigma fluxes with multi-band photometry, yielding stellar masses and infrared-derived star formation rates, place some first constraints on properties z~1.6 environments. measure sizable reservoirs 0.5-2x10^11 solar...
Abstract We present a new empirical Type Ia supernova (SN Ia) model with three chromatic flux variation templates: one phase dependent and two independent. No underlying dust extinction or patterns of intrinsic variability are assumed. Implemented S tan trained using spectrally binned Nearby Supernova Factory spectrophotometry, we examine this model's 2D, phase-independent space motivated basis representations. In both, the first template captures that appears dust-like, while second...
We present GIGA-Lens: a gradient-informed, GPU-accelerated Bayesian framework for modeling strong gravitational lensing systems, implemented in TensorFlow and JAX. The three components, optimization using multi-start gradient descent, posterior covariance estimation with variational inference, sampling via Hamiltonian Monte Carlo, all take advantage of information through automatic differentiation massive parallelization on graphics processing units (GPUs). test our pipeline large set...
Abstract The morphology–density relationship states that dense cosmic environments such as galaxy clusters have an overabundance of quiescent elliptical galaxies, but it is unclear at which redshift this first established. We study the morphology four with 1.2 < z 1.8 using Hubble Space Telescope imaging and computation code statmorph . By comparing median cluster galaxies to CANDELS field Monte Carlo analysis, we find two out (at = 1.19 1.75) established more than 3 σ significance....
Abstract We present a novel method to produce empirical generative models of all kinds astronomical transients from data sets unlabeled light curves. Our hybrid model, which we call ParSNIP, uses neural network model the unknown intrinsic diversity different and an explicit physics-based how transient propagates through universe is observed. The ParSNIP predicts time-varying spectra despite only being trained on photometric observations. With three-dimensional are able fit out-of-sample...
We introduce a method for identifying "twin" Type Ia supernovae, and using them to improve distance measurements. This novel approach supernova standardization is made possible by spectrophotometric time series observations from the Nearby Supernova Factory (SNfactory). begin with well-measured set of find pairs whose spectra match well across entire optical window, then test whether this leads smaller dispersion in their absolute brightnesses. analysis completed blinded fashion, ensuring...
Abstract Hot, dust-obscured galaxies, or “Hot DOGs,” are a rare, dusty, hyperluminous galaxy population discovered by the WISE mission. Predominantly at redshifts 2–3, they include most luminous known galaxies in universe. Their high luminosities likely come from accretion onto highly obscured supermassive black holes (SMBHs). We have conducted pilot survey to measure SMBH masses of five <?CDATA $z\sim 2$?> Hot DOGs via broad H α emission lines, using Keck/MOSFIRE and Gemini/FLAMINGOS-2....
We present confirmation of the cluster MOO J1142+1527, a massive galaxy discovered as part Massive and Distant Clusters WISE Survey. The is confirmed to lie at z = 1.19, using Combined Array for Research in Millimeter-wave Astronomy we robustly detect Sunyaev–Zel'dovich (SZ) decrement 13.2σ. SZ data imply mass M200m (1.1 ± 0.2) × 1015M⊙, making J1142+1527 most known > 1.15 second 1. For standard ΛCDM cosmology it further expected be one ∼5 clusters exist ≥ 1.19 over entire sky. Our ongoing...
As a candidate 'super-Chandrasekhar' or 09dc-like Type Ia supernova (SN Ia), SN 2012dn shares many characteristics with other members of this remarkable class objects but lacks their extraordinary luminosity. Here, we present and discuss the most comprehensive optical data set to date, comprised densely sampled series early-time spectra obtained within Nearby Supernova Factory project, plus photometry spectroscopy at VLT about 1 yr after explosion. The light curves, colour spectral time...
Abstract We calibrate spectrophotometric optical spectra of 32 stars commonly used as standard stars, referenced to 14 already on the Hubble Space Telescope–based CALSPEC flux system. Observations and non-CALSPEC were obtained with SuperNova Integral Field Spectrograph over wavelength range 3300–9400 Å calibration for Nearby Supernova Factory cosmology experiment. In total, this analysis 4289 standard-star taken photometric nights. As a modern analysis, all presubmission methodological...
Abstract We present the discovery and measurements of a gravitationally lensed supernova (SN) behind galaxy cluster MOO J1014+0038. Based on multi-band Hubble Space Telescope Very Large (VLT) photometry supernova, VLT spectroscopy host galaxy, we find 97.5% probability that this SN is Ia, 2.5% chance CC SN. Our typing algorithm combines shape color light curve with expected rates each type in galaxy. With redshift 2.2216, highest Ia discovered spectroscopic host-galaxy redshift. A further...
We study the spectral diversity of Type Ia supernovae (SNe Ia) at maximum light using high signal-to-noise spectrophotometry 173 SNe from Nearby Supernova Factory. decompose these spectra into different extrinsic and intrinsic components, we construct a nonlinear parameterization that preserves pairings "twin" Ia. call this "Twins Embedding". Our methodology naturally handles highly variability in spectra, such as changes photosphere expansion velocity, uses full spectrum rather than being...
Correction of Type Ia Supernova brightnesses for extinction by dust has proven to be a vexing problem. Here we study the foreground highly reddened SN 2012cu, which is projected onto lane in galaxy NGC 4772. The analysis based on multi-epoch, spectrophotometric observations spanning 3,300 - 9,200 {\AA}, obtained Nearby Factory. Phase-matched comparison spectroscopically twinned 2012cu and 2011fe across 10 epochs results best-fit color excess (E(B-V), RMS) = (1.00, 0.03) total-to-selective...
Type Ia Supernovae (SNe Ia) are widely used to measure the expansion of Universe. Improving distance measurements SNe is one technique better constrain acceleration and determine its physical nature. This document develops a new spectral energy distribution (SED) model, called SUpernova Generator And Reconstructor (SUGAR), which improves description Ia, consequently could improve measurements. model constructed from properties spectrophotometric data The Nearby Supernova Factory...
We compile a sample of spectroscopically- and photometrically-selected cluster galaxies from four high-redshift galaxy clusters ($1.59 < z 1.71$) the Spitzer Adaptation Red-Sequence Cluster Survey (SpARCS), comparison field selected UKIDSS Deep Survey. Using near-infrared imaging \textit{Hubble Space Telescope} we classify potential mergers involving massive ($M_* \geq 3\times 10^{10}\mathrm{M}_\odot$) members by eye, based on morphological properties such as tidal distortions, double...
The See Change survey was designed to make $z>1$ cosmological measurements by efficiently discovering high-redshift Type Ia supernovae (SNe Ia) and improving cluster mass through weak lensing. This observed twelve galaxy clusters with the Hubble Space Telescope spanning redshift range $z=1.13$ $1.75$, 57 likely transients 27 SNe at $z\sim 0.8-2.3$. As in similar previous surveys (Dawson et al. 2009), this proved be a highly efficient use of HST for SN observations; additionally tested...
The formation of the stellar mass within galaxy cluster cores is a poorly understood process. It features complicated physics cooling flows, AGN feedback, star and more. Here, we study growth in vicinity Brightest Cluster Galaxy (BCG) z = 1.7 cluster, SpARCS1049+56. We synthesize reanalysis existing HST imaging, previously published measurement rate, results new radio molecular gas spectroscopy. These analyses represent past, present future respectively this system. show that large amount --...
We apply the color-magnitude intercept calibration method (CMAGIC) to Nearby Supernova Factory SNe Ia spectrophotometric dataset. The currently existing CMAGIC parameters are slope and of a straight line fit first linear region in diagram, which occurs over span approximately 30 days after maximum brightness. define new parameter, $\omega_{XY}$, size ``bump'' feature near brightness for arbitrary filters $X$ $Y$. find significant correlation between region, $\beta_{XY, 1}$, diagram...
Abstract The light from an extragalactic source at a distance d will arrive detectors separated by 100 au times that differ as much 120( /100 Mpc) −1 nanoseconds because of the curvature wave front. At gigahertz frequencies, arrival time difference point can be determined to better than nanosecond with interferometry. If spacetime positions are known few centimeters, comparable accuracy which very long baseline interferometry baselines and global navigation satellite systems (GNSS)...
Context. Observations of type Ia supernovae (SNe Ia) can be used to derive accurate cosmological distances through empirical standardization techniques. Despite this success neither the progenitors SNe nor explosion process are fully understood. The U -band region has been less well observed for nearby SNe, due technical challenges, but is most readily accessible band high-redshift SNe. Aims. Using spectrophotometry from Nearby Supernova Factory, we study origin and extent spectroscopic...