A. V. Filippenko
A5044578338- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Astronomical Observations and Instrumentation
- Galaxies: Formation, Evolution, Phenomena
- Astro and Planetary Science
- SAS software applications and methods
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Neutrino Physics Research
- Geophysics and Gravity Measurements
- Solar and Space Plasma Dynamics
- Radio Astronomy Observations and Technology
- Cosmology and Gravitation Theories
- Nuclear Physics and Applications
- History and Developments in Astronomy
- Particle Accelerators and Free-Electron Lasers
- Calibration and Measurement Techniques
- Optical Systems and Laser Technology
- Mechanics and Biomechanics Studies
- Geological and Geophysical Studies
- CCD and CMOS Imaging Sensors
University of California, Berkeley
2016-2025
University of California System
2001-2024
Miller College
2017-2023
Turku Centre for Computer Science
2023
University of Turku
2023
Berkeley College
2000-2022
Hudson Institute
2021
Google (United States)
2021
University of Rijeka
2021
Astronomical Society of the Pacific
2002-2021
We present spectral and photometric observations of 10 Type Ia supernovae (SNe Ia) in the redshift range 0.16 ≤ z 0.62. The luminosity distances these objects are determined by methods that employ relations between SN light curve shape. Combined with previous data from our High-z Supernova Search Team recent results Riess et al., this expanded set 16 high-redshift a 34 nearby used to place constraints on following cosmological parameters: Hubble constant (H0), mass density (ΩM), (i.e.,...
We report measurements of the mass density, ΩM, and cosmological-constant energy ΩΛ, universe based on analysis 42 type Ia supernovae discovered by Supernova Cosmology Project. The magnitude-redshift data for these supernovae, at redshifts between 0.18 0.83, are fitted jointly with a set from Calán/Tololo Survey, below 0.1, to yield values cosmological parameters. All supernova peak magnitudes standardized using SN light-curve width-luminosity relation. measurement yields joint probability...
We have discovered 16 Type Ia supernovae (SNe Ia) with the Hubble Space Telescope (HST) and used them to provide first conclusive evidence for cosmic deceleration that preceded current epoch of acceleration. These objects, during course GOODS ACS Treasury program, include 6 7 highest redshift SNe known, all at z > 1.25, populate diagram in unexplored territory. The luminosity distances these objects 170 previously reported been determined using empirical relations between light-curve shape...
We describe a correlation between the mass M_BH of galaxy's central black hole and luminosity-weighted line-of-sight velocity dispersion sigma_e within half-light radius. The result is based on sample 26 galaxies, including 13 galaxies with new determinations masses from Hubble Space Telescope measurements stellar kinematics. best-fit = 1.2 (+-0.2) x 10^8 M_sun (sigma_e/200 km/s)^(3.75 (+-0.3))over almost three orders magnitude in M_BH; scatter at fixed only 0.30 dex most this due to...
Observations of nearby galaxies reveal a strong correlation between the mass central dark object M and velocity dispersion sigma host galaxy, form log(M/M_sun) = + b*log(sigma/sigma_0); however, published estimates slope b span wide range (3.75 to 5.3). Merritt & Ferrarese have argued that low slopes (<4) arise because neglect random measurement errors in dispersions an incorrect choice for Milky Way Galaxy. We show these explanations account at most small part range. Instead, arises...
We use the Wide Field Camera 3 (WFC3) on Hubble Space Telescope (HST) to reduce uncertainty in local value of constant (H_0) from 3.3% 2.4%. Improvements come new, near-infrared observations Cepheid variables 11 new hosts recent SNe~Ia, more than doubling sample SNe~Ia having a Cepheid-calibrated distance for total 19; these leverage magnitude-z relation based 300 at z<0.15. All 19 and megamaser system NGC4258 were observed with WFC3, thus nullifying cross-instrument zeropoint errors. Other...
The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, over approximate redshift (z) range 8--1.5. It will image >250,000 distant galaxies using three separate cameras on Hubble Space Telescope, from mid-ultraviolet near-infrared, and find measure Type Ia supernovae at z>1.5 test their accuracy as standardizable candles for cosmology. Five premier multi-wavelength sky regions are selected, each with...
Aims. We present cosmological constraints from a joint analysis of type Ia supernova (SN Ia) observations obtained by the SDSS-II and SNLS collaborations. The dataset includes several low-redshift samples (z< 0.1), all three seasons (0.05 <z< 0.4), years (0.2 1), it totals 740 spectroscopically confirmed supernovae with high-quality light curves.
We have discovered 21 new Type Ia supernovae (SNe Ia) with the Hubble Space Telescope (HST) and used them to trace history of cosmic expansion over last 10 billion yr. These objects, which include 13 spectroscopically confirmed SNe at z ≥ 1, were during 14 epochs reimaging GOODS fields North South 2 yr Advanced Camera for Surveys on HST. Together a recalibration our previous HST-discovered Ia, full sample 23 1 provides highest redshift known. Combining these data SN sets, we measured H(z)...
The High-z Supernova Search Team has discovered and observed 8 new supernovae in the redshift interval z=0.3-1.2. These independent observations, confirm result of Riess et al. (1998a) Perlmutter (1999) that supernova luminosity distances imply an accelerating universe. More importantly, they extend range consistently SN Ia to z~1, where signature cosmological effects opposite sign some plausible systematic effects. Consequently, these measurements not only provide another quantitative...
▪ Abstract The temporal evolution of the optical spectra various types supernovae (SNe) is illustrated, in part to aid observers classifying supernova candidates. Type II SNe are defined by presence hydrogen, and they exhibit a very wide variety photometric spectroscopic properties. Among hydrogen-deficient (Type I), three subclasses now known: those whose early-time show strong Si (Ia), prominent He I (Ib), or neither nor (Ic). late-time Ia consist multitude blended emission lines...
We have developed a technique to systematically discover and study high-redshift supernovae that can be used measure the cosmological parameters. report here results based on initial seven of more than 28 discovered date in supernova search Supernova Cosmology Project. find an observational dispersion peak magnitudes σMB=0.27; this narrows σMB, corr=0.19 after "correcting" using light-curve "width-luminosity" relation found for nearby (z ≤ 0.1) Type Ia from Calán/Tololo survey (Hamuy et...
We use the Wide Field Camera 3 (WFC3) on Hubble Space Telescope to determine constant (H0) from optical and infrared observations of over 600 Cepheid variables in host galaxies 8 recent Type Ia supernovae (SNe Ia), providing calibration for a mag-z relation 253 SNe Ia. Increased precision past measurements comes from: (1) more than doubling number Cepheids nearby SN hosts; (2) increasing sample ideal calibrators six eight; (3) by 20% with megamaser NGC 4258; (4) reducing difference mean...
The High-Z Supernova Search is an international collaboration to discover and monitor Type Ia supernovae (SNe Ia) at z > 0.2 with the aim of measuring cosmic deceleration global curvature. Our has pursued a basic understanding in nearby universe, discovering observing large sample objects developing methods measure accurate distances SNe Ia. This paper describes extension this program ≥ 0.2, outlining our search techniques follow-up program. We have devised high-throughput filters that...
We derive improved versions of the relations between supermassive black hole mass (M_BH) and host-galaxy bulge velocity dispersion (sigma) luminosity (L) (the M-sigma M-L relations), based on 49 M_BH measurements 19 upper limits. Particular attention is paid to recovery intrinsic scatter (epsilon_0) in both relations. find log(M_BH / M_sun) = alpha + beta * log(sigma 200 km/s) with (alpha, beta, epsilon_0) (8.12 +/- 0.08, 4.24 0.41, 0.44 0.06) for all galaxies (8.23 3.96 0.42, 0.31...
We report observations from HST of Cepheids in the hosts 42 SNe Ia used to calibrate Hubble constant (H0). These include all suitable last 40 years at z<0.01, measured with >1000 orbits, more than doubling sample whose size limits precision H0. The are calibrated geometrically Gaia EDR3 parallaxes, masers N4258 (here tripling that Cepheid sample), and DEBs LMC. were same WFC3 instrument filters (F555W, F814W, F160W) negate zeropoint errors. present multiple verifications photometry tests...
This paper describes the Hubble Space Telescope imaging data products and reduction procedures for Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS). survey is designed to document evolution of galaxies black holes at $z\sim1.5-8$, study Type Ia SNe beyond $z>1.5$. Five premier multi-wavelength sky regions are selected, each with extensive multiwavelength observations. The primary CANDELS consist obtained in Wide Field Camera 3 / infrared channel (WFC3/IR) UVIS channel,...
The Palomar Transient Factory (PTF) is a fully-automated, wide-field survey aimed at systematic exploration of the optical transient sky. performed using new 8.1 square degree camera installed on 48-inch Samuel Oschin telescope Observatory; colors and light curves for detected transients are obtained with automated 60-inch telescope. PTF uses eighty percent 1.2-m fifty 1.5-m time. With an exposure 60-s reaches depth approximately 21.3 in g' 20.6 R (5 sigma, median seeing). Four major...
We have completed an optical spectroscopic survey of the nuclear regions (r < 200 pc) a large sample nearby galaxies. Although main objectives are to search for low-luminosity active galactic nuclei and quantify their luminosity function, database can be used variety other purposes. This paper presents measurements parameters 418 emission-line nuclei, along with compilation global properties all 486 galaxies in survey. Stellar absorption generally poses serious obstacle obtaining accurate...
We present photometric observations of an apparent Type Ia supernova (SN Ia) at a redshift ~1.7, the farthest SN observed to date. The supernova, 1997ff, was discovered in repeat observation by Hubble Space Telescope (HST) Deep Field-North (HDF-N) and serendipitously monitored with NICMOS on HST throughout Thompson et al. Guaranteed-Time Observer (GTO) campaign. type can be determined from host galaxy type: evolved, red elliptical lacking enough recent star formation provide significant...
We present constraints on the dark energy equation-of-state parameter, w=P/(rho c^2), using 60 Type Ia supernovae (SNe Ia) from ESSENCE supernova survey. derive a set of nature assuming flat Universe. By including (Omega_M, w) baryon acoustic oscillations, we obtain value for static parameter w=-1.05^{+0.13}_{-0.12} (stat; 1 sigma) +- 0.11 (sys) and Omega_M=0.274^{+0.033}_{-0.020} with best-fit chi^2/DoF 0.96. These results are consistent those reported by SuperNova Legacy Survey in similar...
We report observations of 240 Cepheid variables obtained with the Near Infrared Camera (NICMOS) through F160W filter on Hubble Space Telescope (HST). The Cepheids are distributed across six recent hosts Type Ia supernovae (SNe Ia) and "maser galaxy" NGC 4258, allowing us to directly calibrate peak luminosities SNe from precise, geometric distance measurements provided by masers. New features our measurement include use same instrument for all ladder homogeneity periods metallicities thus...
We use Type Ia supernovae studied by the High-z Supernova Search Team to constrain properties of an energy component that may have contributed accelerating cosmic expansion. find for a flat geometry equation-of-state parameter unknown component, αx = Px/ρx, must be less than -0.55 (95% confidence) any value Ωm, and it is further limited < -0.60 if Ωm assumed greater 0.1. These values are inconsistent with being topological defects such as domain walls, strings, or textures. The supernova...
We present an updated and revised analysis of the relationship between Hβ broad-line region (BLR) radius luminosity active galactic nucleus (AGN). Specifically, we have carried out two-dimensional surface brightness decompositions host galaxies nine new AGNs imaged with Hubble Space Telescope Wide Field Camera 3. The allow us to create "AGN-free" images galaxies, from which measure starlight contribution optical measured through ground-based spectroscopic aperture. also incorporate 20...
This is the second paper of a series in which we present new measurements observed rates supernovae (SNe) local Universe, determined from Lick Observatory Supernova Search (LOSS). In this paper, complete SN sample constructed, and (uncorrected for host-galaxy extinction) luminosity functions (LFs) SNe are derived. These LFs solve two issues that have plagued previous rate calculations nearby SNe: distribution extinction. We select volume-limited 175 SNe, collect photometry every object fit...