A5041371496- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Galaxies: Formation, Evolution, Phenomena
- Astronomical Observations and Instrumentation
- Astrophysics and Star Formation Studies
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Cosmology and Gravitation Theories
- Adaptive optics and wavefront sensing
- Astro and Planetary Science
- History and Developments in Astronomy
- Geophysics and Gravity Measurements
- Radio Astronomy Observations and Technology
- Relativity and Gravitational Theory
- Calibration and Measurement Techniques
- Scientific Measurement and Uncertainty Evaluation
- Domain Adaptation and Few-Shot Learning
- Complex Systems and Time Series Analysis
- Yersinia bacterium, plague, ectoparasites research
- Spacecraft Design and Technology
- Seismic Waves and Analysis
- Advanced Statistical Methods and Models
- Ionosphere and magnetosphere dynamics
NSF’s NOIRLab
2023-2024
Community Science and Data Center
2023-2024
Texas A&M University
2014-2023
Mitchell Institute
2013-2022
National Astronomical Observatories
2012
Chinese Academy of Sciences
2012
UNSW Sydney
2012
Association of Universities For Research In Astronomy
2005-2011
Kitt Peak National Observatory
2003-2009
The Ohio State University
2009
We present here the final results of Hubble Space Telescope (HST) Key Project to measure constant. summarize our method, results, and uncertainties, tabulate revised distances, give implications these for cosmology. Our are based on a Cepheid calibration several secondary distance methods applied over range about 60-400 Mpc. The analysis presented benefits from number recent improvements refinements, including (1) larger LMC sample define fiducial period-luminosity (PL) relations, (2) more...
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...
Abstract We present an improved determination of the Hubble constant from Space Telescope (HST) observations 70 long-period Cepheids in Large Magellanic Cloud (LMC). These were obtained with same WFC3 photometric system used to measure extragalactic hosts SNe Ia. Gyroscopic control HST was employed reduce overheads while collecting a large sample widely separated Cepheids. The Cepheid period–luminosity relation provides zero-point-independent link 0.4% precision between new 1.2% geometric...
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...
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...
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 present an expanded sample of 75 Milky Way Cepheids with Hubble Space Telescope (HST) photometry and Gaia EDR3 parallaxes which we use to recalibrate the extragalactic distance ladder refine determination constant. All HST observations were obtained same instrument (WFC3) filters (F555W, F814W, F160W) used for imaging in Type Ia supernova (SN Ia) hosts. The WFC3 spatial scanning mode mitigate saturation reduce pixel-to-pixel calibration errors, reaching a mean photometric error 5...
We present 1210 Johnson/Cousins B, V, R, and I photometric observations of 22 recent Type Ia supernovae (SNe Ia): SNe 1993ac, 1993ae, 1994M, 1994S, 1994T, 1994Q, 1994ae, 1995D, 1995E, 1995al, 1995ac, 1995ak, 1995bd, 1996C, 1996X, 1996Z, 1996ab, 1996ai, 1996bk, 1996bl, 1996bo, 1996bv. Most the photometry was obtained at Fred Lawrence Whipple Observatory Harvard-Smithsonian Center for Astrophysics in a cooperative observing plan aimed improving database Ia. The redshifts sample range from cz =...
Abstract We present Hubble Space Telescope (HST) photometry of a selected sample 50 long-period, low-extinction Milky Way Cepheids measured on the same WFC3 F 555 W -, 814 and 160 -band photometric system as extragalactic in Type Ia supernova host galaxies. These bright were observed with spatial scanning mode optical near-infrared to mitigate saturation reduce pixel-to-pixel calibration errors reach mean error 5 mmag per observation. use new Gaia DR2 parallaxes HST simultaneously constrain...
We present the results of 2MASS Redshift Survey (2MRS), a ten-year project to map full three-dimensional distribution galaxies in nearby universe. The Two Micron All Sky (2MASS) was completed 2003 and its final data products, including an extended source catalog (XSC), are available online. XSC contains nearly million with Ks ⩽ 13.5 mag is essentially complete mostly unaffected by interstellar extinction stellar confusion down galactic latitude |b| = 5° for bright galaxies. Near-infrared...
Since the launch of Hubble Space Telescope (HST) 9 yr ago, Cepheid distances to 25 galaxies have been determined for purpose calibrating secondary distance indicators. Eighteen these measured by HST Key Project team, six Supernova Calibration Project, and one independently Tanvir. Collectively, this work sets out an array survey markers over region within Mpc Milky Way. A variety indicators can now be calibrated, accompanying four papers employ full set consider Tully-Fisher relation,...
We present multiband photometry of 185 type-Ia supernovae (SNe Ia), with over 11,500 observations. These were acquired between 2001 and 2008 at the F. L. Whipple Observatory Harvard-Smithsonian Center for Astrophysics (CfA). This sample contains largest number homogeneously observed reduced nearby SNe Ia (z ≲ 0.08) published to date. It more than doubles sample, bringing SN cosmology point where systematic uncertainties dominate. Our natural system has a precision ≲0.02 mag in BVRIr'i' ≲0.04...
We present new parallax measurements of 7 long-period (> 10 days) Milky Way Cepheids (SS CMa, XY Car, VY VX Per, WZ Sgr, X Pup and S Vul) using astrometry from spatial scanning WFC3 on HST. Observations were obtained at 6 month intervals over 4 years. The distances are 1.7--3.6 kpc with a mean precision 45 microarcseconds best 29 (SNR = 14). accuracy the parallaxes is demonstrated through independent analyses >100 reference stars. This raises to number significant measurements, 8 this...
We present UBVRI photometry of 44 Type Ia supernovae (SNe Ia) observed from 1997 to 2001 as part a continuing monitoring campaign at the Fred Lawrence Whipple Observatory Harvard-Smithsonian Center for Astrophysics. The data set comprises 2190 observations and is largest homogeneously reduced sample SNe date, nearly doubling number well-observed, nearby with published multicolor CCD light curves. large U-band unique addition, important connections high redshift. decline rate SN curves...
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...
Abstract We present Hubble Space Telescope (HST) photometry of 17 Cepheids in open clusters and their cluster mean parallaxes from Gaia EDR3. These are more precise than those individual ( G < 8 mag) previously used to measure the constant because they derived an average >300 stars per cluster. Cluster also have smaller systematic uncertainty lie range > 13 where parallax calibration is most comprehensive. Cepheid employed period–luminosity relation was measured using same HST...
Abstract High-resolution James Webb Space Telescope (JWST) observations can test confusion-limited Hubble (HST) for a photometric bias that could affect extragalactic Cepheids and the determination of constant. We present JWST NIRCAM in two epochs three filters >320 NGC 4258 (which has 1.5% maser-based geometric distance) 5584 (host SN Ia 2007af), near median distance SH0ES HST host sample with best leverage among them to detect such bias. provides far superior source separation from...
Abstract We present high-definition observations with the James Webb Space Telescope (JWST) of >1000 Cepheids in a geometric anchor distance ladder, NGC 4258, and five hosts eight Type Ia supernovae, far greater sample than previous studies JWST. These galaxies individually contain largest samples Cepheids, an average >150 each, producing strongest statistical comparison to those previously measured Hubble (HST) near-infrared (NIR). They also span range used determine constant HST,...
Abstract We present phase-corrected photometric measurements of 88 Cepheid variables in the core Small Magellanic Cloud (SMC), first sample obtained with Hubble Space Telescope's (HST) Wide Field Camera 3, same homogeneous system as past all Cepheids on SH0ES distance ladder. limit to inner and model geometry reduce errors prior studies due nontrivial depth this cloud. Without crowding ground-based studies, we obtain an unprecedentedly low dispersion 0.102 mag for a period–luminosity ( P – L...
Uncertainty in the metal-abundance dependence of Cepheid variable period-luminosity (PL) relation remains one outstanding sources systematic error extragalactic distance scale and Hubble constant. To test for such a metallicity dependence, we have used Wide Field Planetary Camera 2 (WFPC2) on Space Telescope (HST) to observe Cepheids that span range oxygen abundance 0.7 ± 0.15 dex two fields nearby spiral galaxy M101. A differential analysis PL relations V I yields marginally significant...
A Cepheid-based calibration is derived for four distance indicators that utilize stars in the old stellar populations: tip of red giant branch (TRGB), planetary nebula luminosity function (PNLF), globular cluster (GCLF) and surface brightness fluctuation method (SBF). The largely based on Cepheid distances to 18 spiral galaxies within cz =1500 km/s obtained as part HST Key Project Extragalactic Distance Scale, but relies also from separate ground-based efforts. newly SBF applied obtain Abell...
We present the results of applying a percolation algorithm to initial release Two Micron All-Sky Survey Extended Source Catalog, using subsequently measured redshifts for almost all galaxies with K < 11.25 mag. This group catalog is based on first near-IR all-sky flux-limited survey that complete |b| = 5 deg. explore dependence clustering length and velocity scales involved. The paper describes catalog, limiting redshift 10,000 km/s, created by maximizing number groups containing 3 or more...
We present initial results from a time-series BVI survey of two fields in NGC 4258 using the Advanced Camera for Surveys onboard Hubble Space Telescope. This galaxy was selected because its accurate maser-based distance, which is anticipated to have total uncertainty ~3%. The goal HST observations provide an absolute calibration Cepheid Distance Scale and measure dependence on chemical abundance (the so-called "metallicity effect"). carried out at different galactocentric distances with mean...