K. Barbary
A5048639381- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Radiomics and Machine Learning in Medical Imaging
- Galaxies: Formation, Evolution, Phenomena
- Astronomical Observations and Instrumentation
- Computational Physics and Python Applications
- Chemistry and Stereochemistry Studies
- Pulsars and Gravitational Waves Research
- Cosmology and Gravitation Theories
- Chemical Thermodynamics and Molecular Structure
- Adsorption, diffusion, and thermodynamic properties of materials
- Medical Imaging Techniques and Applications
- Neutrino Physics Research
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Adaptive optics and wavefront sensing
- Spectroscopy and Laser Applications
- Astro and Planetary Science
- Protein Tyrosine Phosphatases
- Dark Matter and Cosmic Phenomena
- Cloud Computing and Resource Management
- Cerebrovascular and genetic disorders
- Metalloenzymes and iron-sulfur proteins
Lawrence Berkeley National Laboratory
2011-2021
University of California, Berkeley
2009-2021
Argonne National Laboratory
2013-2014
California Institute of Technology
2004
We present the first public version (v0.2) of open-source and community-developed Python package, Astropy. This package provides core astronomy-related functionality to community, including support for domain-specific file formats such as Flexible Image Transport System (FITS) files, Virtual Observatory (VO) tables, common ASCII table formats, unit physical quantity conversions, constants specific astronomy, celestial coordinate time transformations, world system (WCS) support, generalized...
We present Advanced Camera for Surveys, NICMOS, and Keck adaptive-optics-assisted photometry of 20 Type Ia supernovae (SNe Ia) from the Hubble Space Telescope (HST) Cluster Supernova Survey. The SNe were discovered over redshift interval 0.623 < z 1.415. Of these Ia, 14 pass our strict selection cuts are used in combination with world's sample to derive best current constraints on dark energy. new 10 beyond = 1, thereby nearly doubling statistical weight HST-discovered this redshift. Our...
We present a new compilation of Type Ia supernovae (SNe Ia), dataset low-redshift nearby-Hubble-flow SNe and analysis procedures to work with these heterogeneous compilations. This ``Union'' 414 SN Ia, which reduces 307 after selection cuts, includes the recent large samples from Supernova Legacy Survey ESSENCE Survey, older datasets, as well recently extended distant observed HST. A single, consistent blind procedure is used for all various subsamples, implemented that consistently weights...
We report on work to increase the number of well-measured Type Ia supernovae (SNe Ia) at high redshifts. Light curves, including signal-to-noise Hubble Space Telescope data, and spectra six SNe that were discovered during 2001, are presented. Additionally, for two with z > 1, we present ground-based J-band photometry from Gemini Very Large Telescope. These among most distant which near-IR observations have been obtained. add these together other data sets recently become available in...
Source Extractor (Bertin and Arnouts 1996;Bertin 2016) is a widely used command-line program for segmentation analysis of astronomical images.It reads in FITS format files, performs configurable series tasks, including background estimation, source detection, deblending wide array measurements, finally outputs catalog file.
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...
We present weak gravitational lensing analysis of 22 high-redshift (z >~1) clusters based on Hubble Space Telescope images. Most in our sample provide significant signals and are well detected their reconstructed two-dimensional mass maps. Combining the current results previous weak-lensing studies five other high-z clusters, we compare masses these with observables. revisit question whether presence most massive is tension LambdaCDM structure formation paradigm. find that tightly correlated...
We present observations of SCP 06F6, an unusual optical transient discovered during the Hubble Space Telescope Cluster Supernova Survey. The brightened over a period ~100 days, reached peak magnitude ~21.0 in both i_775 and z_850, then declined similar timescale. There is no host galaxy or progenitor star detected at location to 3 sigma upper limit = 26.4 z_850 26.1, giving corresponding lower on flux increase factor ~120. Multiple spectra show five broad absorption bands between 4100 AA...
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...
We present DES13S2cmm, the first spectroscopically-confirmed superluminous supernova (SLSN) from Dark Energy Survey (DES). briefly discuss data and search algorithm used to find this event in year of DES operations, outline spectroscopic obtained European Southern Observatory (ESO) Very Large Telescope confirm its redshift (z = 0.663 +/- 0.001 based on host-galaxy emission lines) likely spectral type (type I). Using redshift, we M_U_peak -21.05 +0.10 -0.09 for peak, rest-frame U-band...
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 a study of the morphological fractions and color–magnitude relation (CMR) in most distant X-ray selected galaxy cluster currently known, XMMXCS J2215.9 − 1738 at z = 1.46, using combination optical imaging data obtained with Hubble Space Telescope Advanced Camera for Surveys, infrared from Multi-Object Infrared Spectrograph, mounted on 8.2 m Subaru telescope. find that mix population is similar to clusters ∼ 1. Within central 0.5 Mpc, approximately ∼62% galaxies identified as...
We present a new survey strategy to discover and study high-redshift Type Ia supernovae (SNe Ia) using the Hubble Space Telescope (HST). By targeting massive galaxy clusters at 0.9 < z 1.5, we obtain twofold improvement in efficiency of finding SNe compared an HST field factor 3 total yield SN detections relatively dust-free red-sequence galaxies. In total, sixteen were discovered z>0.95, nine which clusters. This provides sample that can be used decouple effects host-galaxy extinction...
We present a new measurement of the volumetric rate SNe Ia up to redshift 1.7, using HST GOODS data combined with an additional set covering GOODS-North field collected in 2004. employ novel technique that does not require spectroscopic for identifying (although measurements redshifts are used over half sample); instead, we Bayesian approach only photometric calculate probability object is SN Ia. This can easily be modified incorporate improved priors on properties, and it well-suited future...
Scientific analyses commonly compose multiple single-process programs into a dataflow. An end-to-end dataflow of is known as many-task application. Typically, tools from the HPC software stack are used to parallelize these analyses. In this work, we investigate an alternate approach that uses Apache Spark - modern big data platform applications. We present Kira, flexible and distributed astronomy image processing toolkit using Spark. then use Kira implement Source Extractor application for...
We report the discovery of a redshift 1.71 supernova in GOODS North field. The Hubble Space Telescope (HST) ACS spectrum has almost negligible contamination from host or neighboring galaxies. Although rest frame sampled range is too blue to include any Si ii line, principal component analysis allows us confirm it as Type Ia with 92% confidence. A recent serendipitous archival HST WFC3 grism contributed key element confirmation by giving host-galaxy 1.713 +/- 0.007. In addition being most...
We report a measurement of the Type Ia supernova (SN Ia) rate in galaxy clusters at 0.9 < z 1.46 from Hubble Space Telescope Cluster Supernova Survey. This is first cluster SN with detected > SNe. Finding 8 ± 1 SNe Ia, we determine an 0.50+0.23−0.19 (stat) +0.10−0.09 (sys) h270 SNuB (SNuB ≡ 10−12 L−1☉, B yr−1). In units stellar mass, this translates to 0.36+0.16−0.13 +0.07−0.06 SNuM (SNuM M−1☉ represents factor ≈5 2 increase over measurements 0.2. parameterize late-time delay time...