A5049702993- Gamma-ray bursts and supernovae
- Particle physics theoretical and experimental studies
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Quantum Chromodynamics and Particle Interactions
- Stellar, planetary, and galactic studies
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Pulsars and Gravitational Waves Research
- Dark Matter and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Particle Detector Development and Performance
- Astrophysical Phenomena and Observations
- Nuclear Physics and Applications
- Galaxies: Formation, Evolution, Phenomena
- Adaptive optics and wavefront sensing
- Nuclear physics research studies
- Atomic and Subatomic Physics Research
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- CCD and CMOS Imaging Sensors
- Particle Accelerators and Free-Electron Lasers
- Astro and Planetary Science
- Cosmology and Gravitation Theories
- Medical Imaging Techniques and Applications
Yale University
2015-2024
University of Oregon
2015
Indiana University Bloomington
2009
Lawrence Berkeley National Laboratory
2000-2006
Aomori University
2002
Michigan State University
2000
Johns Hopkins University
2000
Lawrence Livermore National Laboratory
2000
University at Buffalo, State University of New York
2000
Stony Brook University
2000
DESI (Dark Energy Spectroscopic Instrument) is a Stage IV ground-based dark energy experiment that will study baryon acoustic oscillations (BAO) and the growth of structure through redshift-space distortions with wide-area galaxy quasar redshift survey. To trace underlying matter distribution, spectroscopic targets be selected in four classes from imaging data. We measure luminous red galaxies up to $z=1.0$. probe Universe out even higher redshift, target bright [O II] emission line $z=1.7$....
This report describes the 2014 study by Science Definition Team (SDT) of Wide-Field Infrared Survey Telescope (WFIRST) mission. It is a space observatory that will address most compelling scientific problems in dark energy, exoplanets and general astrophysics using 2.4-m telescope with wide-field infrared instrument an optical coronagraph. The Astro2010 Decadal recommended Wide Field as its top priority for new large As conceived decadal survey, WFIRST would carry out energy science program,...
We present photometric and spectroscopic observations of SN 2007if, an overluminous (MV = −20.4), red (B − V 0.16 at B-band maximum), slow-rising (trise 24 days) type Ia supernova (SN Ia) in a very faint (Mg −14.10) host galaxy. A spectrum 5 days past maximum light is direct match to the super-Chandrasekhar-mass candidate 2003fg, showing Si ii C ∼9000 km s−1. high signal-to-noise co-addition spectral time series reveals no Na i D absorption, suggesting negligible reddening galaxy, late-time...
High-quality collections of Type II supernova (SN) light curves are scarce because they evolve for hundreds days, making follow-up observations time consuming and often extending over multiple observing seasons. In these difficulties, the diversity SNe is not fully understood. Here we present ultraviolet optical photometry 12 monitored by Las Cumbres Observatory Global Telescope Network during 2013 to 2014, compare them with previously studied having well-sampled curves. We explore SN...
DESI (Dark Energy Spectropic Instrument) is a Stage IV ground-based dark energy experiment that will study baryon acoustic oscillations and the growth of structure through redshift-space distortions with wide-area galaxy quasar redshift survey. The instrument robotically-actuated, fiber-fed spectrograph capable taking up to 5,000 simultaneous spectra over wavelength range from 360 nm 980 nm. fibers feed ten three-arm spectrographs resolution $R= λ/Δλ$ between 2000 5500, depending on...
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...
The Public European Southern Observatory Spectroscopic Survey of Transient Objects (PESSTO) began as a public spectroscopic survey in April 2012. We describe the data reduction strategy and products which are publicly available through ESO archive Data Release 1 (SSDR1). PESSTO uses New Technology Telescope with EFOSC2 SOFI to provide optical NIR spectroscopy imaging. target supernovae transients brighter than 20.5mag for classification. Science targets then selected follow-up based on...
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...
The Dark Energy Spectroscopic Instrument (DESI) was designed to conduct a survey covering 14,000 deg$^2$ over five years constrain the cosmic expansion history through precise measurements of Baryon Acoustic Oscillations (BAO). scientific program for DESI evaluated during month Survey Validation (SV) campaign before beginning full operations. This produced deep spectra tens thousands objects from each stellar (MWS), bright galaxy (BGS), luminous red (LRG), emission line (ELG), and quasar...
Abstract The Dark Energy Spectroscopic Instrument (DESI) completed its 5 month Survey Validation in 2021 May. Spectra of stellar and extragalactic targets from constitute the first major data sample DESI survey. This paper describes public release those spectra, catalogs derived properties, intermediate products. In total, includes good-quality spectral information 466,447 objects targeted as part Milky Way Survey, 428,758 Bright Galaxy 227,318 Luminous Red sample, 437,664 Emission Line...
Abstract A system of 5020 robotic fiber positioners was installed in 2019 on the Mayall Telescope, at Kitt Peak National Observatory. The robots automatically retarget their optical fibers every 10–20 minutes, each to a precision several microns, with reconfiguration time fewer than 2 minutes. Over next 5 yr, they will enable newly constructed Dark Energy Spectroscopic Instrument (DESI) measure spectra 35 million galaxies and quasars. DESI produce largest 3D map universe date expansion...
We present the DESI 2024 galaxy and quasar baryon acoustic oscillations (BAO) measurements using over 5.7 million unique redshifts in range 0.1<z<2.1. Divided by tracer type, we utilize 300,017 galaxies from magnitude-limited Bright Galaxy Survey with 0.1<z<0.4, 2,138,600 Luminous Red Galaxies 0.4<z<1.1, 2,432,022 Emission Line 0.8<z<1.6, 856,652 quasars 0.8<z<2.1, a ~7,500 square degree footprint. The analysis was blinded at catalog-level to avoid confirmation bias. All fiducial choices of...
Abstract We present the measurement of Baryon Acoustic Oscillations (BAO) from Lyman- α (Ly ) forest high-redshift quasars with first-year dataset Dark Energy Spectroscopic Instrument (DESI). Our analysis uses over 420 000 Ly spectra and their correlation spatial distribution more than 700 quasars. An essential facet this work is development a new methodology on blinded dataset. conducted rigorous tests using synthetic data to ensure reliability our findings before unblinding. Additionally,...
We report Nearby Supernova Factory observations of SN 2005gj, the second confirmed case a "hybrid" Type Ia/IIn supernova. Our early-phase photometry 2005gj shows that interaction is much stronger than for prototype, 2002ic. first spectrum hot continuum with broad and narrow H-alpha emission. Later spectra, spanning over 4 months from outburst, show clear Ia features combined H-gamma, H-beta, HeI 5876,7065 in At higher resolution, P Cygni profiles are apparent. Surprisingly, we also observe...
The nearby supernova SN 2011fe can be observed in unprecedented detail. Therefore, it is an important test case for Type Ia (SN Ia) models, which may bring us closer to understanding the physical nature of these objects. Here, we explore how available and expected future observations used constrain explosion scenarios. We base our discussion on three-dimensional simulations a delayed detonation Chandrasekhar-mass white dwarf violent merger two dwarfs-realizations models appropriate most...
We have measured the periods and light curves of 148 RR Lyrae variables from V = 13.5 to 19.7 first 100 deg2 Quasar Equatorial Survey Team survey. Approximately 55% these stars belong clump detected earlier by Sloan Digital Sky Survey. According our measurements, this feature has ~10 times background density halo stars, spans at least 375 35 in α δ (≥30 ≥3 kpc), lies ~50 kpc Sun, a depth along line sight ~5 (1 σ). These properties are consistent with recent models that suggest it is tidal...
We present 32 epochs of optical (3300-9700 \AA) spectrophotometric observations the nearby quintessential "normal" type Ia supernova (SN Ia) SN 2011fe in galaxy M101, extending from -15 to +97 d with respect B-band maximum, obtained by Nearby Supernova Factory collaboration. is closest (\mu = 29.04) and brightest (Bmax 9.94 mag) observed since advent modern large scale programs for intensive periodic followup supernovae. Both synthetic light curve measurements spectral feature analysis...
We assemble a sample of 24 hydrogen-poor super-luminous supernovae (SLSNe). Parameterizing the light curve shape through rise and decline timescales shows that two are highly correlated. Magnetar-powered models can reproduce correlation, with diversity in rates driven by diffusion timescale. Circumstellar interaction exhibit similar rise-decline relation, but only for narrow range densities, which may be problematic these models. find SLSNe approximately 3.5 magnitudes brighter have curves 3...
We examine the relationship between Type Ia supernova (SN Ia) Hubble residuals and properties of their host galaxies using a sample 115 SNe from Nearby Supernova Factory. use galaxy stellar masses specific star formation rates fitted photometry for all hosts, as well gas-phase metallicities subset 69 star-forming (non-active galactic nucleus) to show that SN correlate with each these properties. With data we find new evidence correlation intrinsic color metallicity. When combine our those...
We present optical spectra and light curves for three hydrogen-poor superluminous supernovae followed by the Public ESO Spectroscopic Survey of Transient Objects (PESSTO). Time series spectroscopy from a few days after maximum to 100 d later shows them be fairly typical this class, with dominated Ca ii, Mg Fe Si which evolve slowly over most post-peak photospheric phase. determine bolometric apply simple fitting tools, based on diffusion energy input magnetar spin-down, 56Ni decay, collision...
We present a sample of normal Type Ia supernovae (SNe Ia) from the Nearby Supernova Factory data set with spectrophotometry at sufficiently late phases to estimate ejected mass using bolometric light curve. measure 56Ni masses peak luminosity, then compare luminosity in 56Co-decay tail expected rate radioactive energy release ejecta given mass. infer Bayesian context semi-analytic model ejecta, incorporating constraints contemporary numerical models as priors on density structure and...
The reactions pi /sup +/ + p yields 0/ and pi/sup n are studied at 910, 1090, 1260 Mev, in an attempt to detect a - resonance. For the outgoing / sup pair, peaks Q-values lead di-pion resonance with mass of 5.0 5.5 pion masses 1= 1 or 2. No is observed (I = 2) leading conclusion that state. (T.F.H.)
We present an analysis of the early, rising light curves 18 Type Ia supernovae (SNe Ia) discovered by Palomar Transient Factory and La Silla-QUEST variability survey. fit these early data flux using a simple power law (f(t) = α × tn) to determine time first (t0), hence rise (trise) from peak luminosity, exponent power-law (n). find mean uncorrected 18.98 ± 0.54 d, with individual supernova (SN) times ranging 15.98 24.7 d. The n shows significant departures 'fireball model' 2 (or f(t) ∝ t2)...