A5074642266- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Astrophysics and Star Formation Studies
- Pulsars and Gravitational Waves Research
- Cosmology and Gravitation Theories
- Adaptive optics and wavefront sensing
- Astrophysics and Cosmic Phenomena
- Geophysics and Gravity Measurements
- History and Developments in Astronomy
- Astro and Planetary Science
- Scientific Research and Discoveries
- Radio Astronomy Observations and Technology
- Solar and Space Plasma Dynamics
- Neutrino Physics Research
- Relativity and Gravitational Theory
- Scientific Measurement and Uncertainty Evaluation
- Particle Detector Development and Performance
- Advanced Nanomaterials in Catalysis
- Veterinary Equine Medical Research
- CCD and CMOS Imaging Sensors
- Impact of Light on Environment and Health
Johns Hopkins University
2018-2024
Texas A&M University
2015-2018
Mitchell Institute
2015-2018
Tsinghua University
2015
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 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 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...
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 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 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...
The tip of the red giant branch has been used to measure distances 500 nearby galaxies with Hubble Space Telescope (HST) which are available in Color-Magnitude Diagrams and Tip Red Giant Branch (CMDs/TRGB) catalog on Extragalactic Distance Database (EDD). Our established methods employed perform an independent reduction targets presented by Carnegie-Chicago Program (CCHP) series papers culminating Freedman (2021). distinct methodology involves modeling observed luminosity function asymptotic...
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...
Abstract We present a calibration of the tip red giant branch (TRGB) in Large Magellanic Cloud (LMC) on Hubble Space Telescope ( HST )/ACS F814W system. use archival observations to derive blending corrections and photometric transformations for two ground-based wide-area imaging surveys Clouds. show that these are biased bright by up ∼0.1 mag optical due blending, bias is function local stellar density. correct LMC TRGB magnitudes from Jang & Lee geometric distance Pietrzyński et al....
Abstract We present year-long, near-infrared Hubble Space Telescope ( HST ) WFC3 observations used to search for Mira variables in NGC 1559, the host galaxy of Type Ia supernova (SN Ia) SN 2005df. This is first dedicated Miras, highly evolved low-mass stars, an host, and subsequently calibration luminosity using Miras a role historically played by Cepheids. identify sample 115 O-rich with P < 400 days based on their light-curve properties. find that scatter period–luminosity relation...
Abstract The tip of the red giant branch (TRGB) allows for measurement precise and accurate distances to nearby galaxies based on brightest ascent low-mass stars before they undergo helium flash. With advent JWST, there is great promise utilize technique measure galaxy out at least 50 Mpc, significantly further than Hubble Space Telescope's (HST's) reach 20 Mpc. However, with any standard candle, it first necessary provide an absolute reference. Here, we use Cycle 1 data calibration in F090W...
Abstract We cross-check the Hubble Space Telescope (HST) Cepheid/Type Ia supernova (SN Ia) distance ladder, which yields most precise local H 0 , against early James Webb (JWST) subsamples (∼1/4 of HST sample) from SH0ES and CCHP, calibrated only with NGC 4258. find Cepheid distances agree well (∼1 σ ) all combinations methods, samples, telescopes. The comparisons explicitly include measurement uncertainty each method in 4258, an oft-neglected but dominant term. Mean differences are ∼0.03...
Abstract The giant spiral galaxy M101 is host to the nearest recent Type Ia supernova (SN 2011fe) and thus has been extensively monitored in near-infrared study late-time light curve of SN. Leveraging this existing baseline observations, we derive first Mira-based distance by discovering classifying a sample 211 Miras with periods ranging from 240–400 days SN field. Combined new Hubble Space Telescope (HST) WFC3/IR channel our data set totals 11 epochs F110W (HST YJ ) 13 F160W H spanning...
Abstract We study stars in the J-regions of asymptotic giant branch (JAGB) near-infrared color–magnitude diagrams maser host NGC 4258 and four hosts six Type Ia supernovae (SNe Ia): 1448, 1559, 5584, 5643. These clumps are readily apparent near 1.0 < F150W − F277W 1.5 m = 22–25 mag with James Webb Space Telescope NIRCam photometry. Various methods have been proposed to assign an reference magnitude this recently standard candle, including mode, median, sigma-clipped mean, or a modeled...
We present year-long, near-infrared Hubble Space Telescope WFC3 observations of Mira variables in the water megamaser host galaxy NGC 4258. Miras are AGB that can be divided into oxygen- (O-) and carbon- (C-) rich subclasses. Oxygen-rich follow a tight (scatter $\sim 0.14$ mag) Period-Luminosity Relation (PLR) used to measure extragalactic distances. The 4258 gives geometric distance accurate 2.6% serve calibrate PLR. develop criteria for detecting classifying O-rich with optical NIR data as...
The three rung distance ladder, which calibrates Type Ia supernovae through stellar distances linked to geometric measurements, provides the highest precision direct measurement of Hubble constant. In light tension, it is important test individual components ladder. For this purpose, we report a constant from 35 extragalactic Cepheid hosts measured by SH0ES team, using their and redshifts at cz < 3300 km /s , instead any, more distant supernovae, measure flow. are calibrated geometrically in...
ABSTRACT The SH0ES collaboration Hubble constant determination is in a ∼5σ difference with the Planck value, known as tension. accuracy of measured extragalactic Cepheids depends on robust stellar-crowding background estimation. Riess et al. (R20) compared light-curve amplitudes and MW to constrain an unaccounted systematic blending bias, $\gamma =-0.029\pm 0.037\, \rm {mag}$, which cannot explain required, =0.24\pm 0.05\, resolve Further checks by demonstrate that possible not likely...
Abstract The Hubble Tension, a >5 σ discrepancy between direct and indirect measurements of the constant ( H 0 ), has persisted for decade motivated intense scrutiny paths used to infer . Comparing independently derived distances set galaxies with different standard candles, such as tip red giant branch (TRGB) Cepheid variables, can test systematics in middle rung distance ladder. I band is preferred filter measuring TRGB due constancy color, result low sensitivity population differences...
We present results of an optical search for Cepheid variable stars using the Hubble Space Telescope (HST) in 19 hosts Type Ia supernovae (SNe Ia) and maser-host galaxy NGC 4258, conducted as part SH0ES project (Supernovae H0 Equation State dark energy). The targets include 9 newly imaged SN a novel strategy based on long-pass filter that minimizes number HST orbits required to detect accurately determine properties. carried out homogeneous reduction analysis all observations, including new...
We derive a distance of $15.8\pm0.4$ Mpc to the archetypical Seyfert 1 galaxy NGC 4151 based on near-infrared Cepheid Period-Luminosity relation and new Hubble Space Telescope multiband imaging. This determination, measurements 35 long-period ($P > 25$d) Cepheids, will support absolute calibration supermassive black hole mass in this system, as well studies dynamics feedback or feeding its active galactic nucleus.