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All sources NASA NTRS DOE OSTI

DOE OSTI2019

Baryon acoustic oscillation, Hubble parameter, and angular size measurement constraints on the Hubble constant, dark energy dynamics, and spatial curvature

ABSTRACT In this paper, we use all available baryon acoustic oscillation, Hubble parameter, and quasar angular size data to constrain six dark energy cosmological models, both spatially flat and non-flat. Depending on the model and data combination considered, these data mildly favour closed spatial hypersurfaces (by as much as 1.7σ) and dark energy dynamics (up to a little over 2σ) over a cosmological constant Λ. The data also favour, at 1.8σ to 3.4σ, depending on the model and data combination, a lower Hubble constant than what is measured from the local expansion rate.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2017

Determining the hubble constant from hubble parameter measurements

We use 28 measurements of the Hubble parameter, H(z), at intermediate redshifts 0.07⩽z⩽2.3 to determine the present-day Hubble constant H{sub 0} in four cosmological models. We measure H{sub 0}=68.3{sub −2.6}{sup +2.7},68.4{sub −3.3}{sup +2.9},65.0{sub −6.6}{sup +6.5}, and 67.9{sub −2.4}{sup +2.4} km s{sup −1} Mpc{sup −1} (1σ errors) in the ΛCDM (spatially flat and non-flat), ωCDM, and ϕCDM models, respectively. These measured H{sub 0} values are more consistent with the lower values determined from recent data on the cosmic microwave background and baryon acoustic oscillations, as well as with the value found from a median statistical analysis of Huchra’s compilation of H{sub 0} measurements, but include the higher local measurements of H{sub 0} within the 2σ confidence limits.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2019

Measuring the Hubble constant and spatial curvature from supernova apparent magnitude, baryon acoustic oscillation, and Hubble parameter data

Cosmic microwave background (CMB) anisotropy (spatial inhomogeneity) data provide the tightest constraints on the Hubble constant, matter density, spatial curvature, and dark energy dynamics. Other data, sensitive to the evolution of only the spatially homogeneous part of the cosmological model, such as Type Ia supernova apparent magnitude, baryon acoustic oscillation distance, and Hubble parameter measurements, can be used in conjunction with the CMB data to more tightly constrain parameters. Recent joint analyses of CMB and such non-CMB data indicate that slightly closed spatial hypersurfaces are favored in nonflat untilted inflation models and that dark energy dynamics cannot be ruled out, and favor a smaller Hubble constant. Here, we show that the constraints that follow from these non-CMB data alone are consistent with those that follow from the CMB data alone and so also consistent with, but weaker than, those that follow from the joint analyses of the CMB and non-CMB data.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2018

Constraints on dark energy dynamics and spatial curvature from Hubble parameter and baryon acoustic oscillation data

We use all available baryon acoustic oscillation distance measurements and Hubble parameter data to constrain the cosmological constant Λ, dynamical dark energy, and spatial curvature in simple cosmological models. Here, we find that the consensus spatially flat ΛCDM (Λ cold dark matter) model provides a reasonable fit to the data, but depending on the Hubble constant prior and cosmological model, it can be a little more than 1σ away from the best-fitting model, which can favour mild dark energy dynamics or non-flat spatial hypersurfaces.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS2012

Carnegie Hubble Program: A Mid-Infrared Calibration of the Hubble Constant

Using a mid-infrared calibration of the Cepheid distance scale based on recent observations at 3.6 micrometers with the Spitzer Space Telescope, we have obtained a new, high-accuracy calibration of the Hubble constant. We have established the mid-IR zero point of the Leavitt law (the Cepheid period-luminosity relation) using time-averaged 3.6 micrometers data for 10 high-metallicity, MilkyWay Cepheids having independently measured trigonometric parallaxes. We have adopted the slope of the PL relation using time-averaged 3.6micrometers data for 80 long-period Large Magellanic Cloud (LMC) Cepheids falling in the period range 0.8 < log(P) < 1.8.We find a new reddening-corrected distance to the LMC of 18.477 +/- 0.033 (systematic) mag. We re-examine the systematic uncertainties in H(sub 0), also taking into account new data over the past decade. In combination with the new Spitzer calibration, the systematic uncertainty in H(sub 0) over that obtained by the Hubble Space Telescope Key Project has decreased by over a factor of three. Applying the Spitzer calibration to the Key Project sample, we find a value of H(sub 0) = 74.3 with a systematic uncertainty of +/-2.1 (systematic) kilometers per second Mpc(sup −1), corresponding to a 2.8% systematic uncertainty in the Hubble constant. This result, in combination with WMAP7measurements of the cosmic microwave background anisotropies and assuming a flat universe, yields a value of the equation of state for dark energy, w(sub 0) = −1.09 +/- 0.10. Alternatively, relaxing the constraints on flatness and the numbers of relativistic species, and combining our results with those of WMAP7, Type Ia supernovae and baryon acoustic oscillations yield w(sub 0) = −1.08 +/- 0.10 and a value of N(sub eff) = 4.13 +/- 0.67, mildly consistent with the existence of a fourth neutrino species.

Program↗

DOE OSTI2017

Sample variance in the local measurements of the Hubble constant

The current >3σ tension between the Hubble constant H 0 measured from local distance indicators and from cosmic microwave background is one of the most highly debated issues in cosmology, as it possibly indicates new physics or unknown systematics. In this work, we explore whether this tension can be alleviated by the sample variance in the local measurements, which use a small fraction of the Hubble volume. We use a large-volume cosmological N-body simulation to model the local measurements and to quantify the variance due to local density fluctuations and sample selection. We explicitly take into account the inhomogeneous spatial distribution of type Ia supernovae. Despite the faithful modelling of the observations, our results confirm previous findings that sample variance in the local Hubble constant ($H$ $^{loc}_{0}$) measurements is small; we find σ ($H$ $^{loc}_{0}$)=0.31km s -1 Mpc -1 a nearly negligible fraction of the ~6 km s -1 Mpc -1 necessary to explain the difference between the local and global H 0 measurements. While the H 0 tension could in principle be explained by our local neighbourhood being a underdense region of radius ~150 Mpc, the extreme required underdensity of such a void (δ ≃ -0.8) makes it very unlikely in a ΛCDM universe, and it also violates existing observational constraints. Furthermore, sample variance in a ΛCDM universe cannot appreciably alleviate the tension in H 0 measurements even after taking into account the inhomogeneous selection of type Ia supernovae.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2021

Using Pantheon and DES supernova, baryon acoustic oscillation, and Hubble parameter data to constrain the Hubble constant, dark energy dynamics, and spatial curvature

ABSTRACT We use Pantheon Type Ia supernova (SN Ia) apparent magnitude, DES-3 yr binned SN Ia apparent magnitude, Hubble parameter, and baryon acoustic oscillation measurements to constrain six spatially flat and non-flat cosmological models. These sets of data provide mutually consistent cosmological constraints in the six cosmological models we study. A joint analysis of these data sets provides model-independent estimates of the Hubble constant, $H_0=68.8\pm 1.8\ \rm {km \, s^{-1} \ Mpc^{-1}}$, and the non-relativistic matter density parameter, $\Omega _{\rm m_0}=0.294\pm 0.020$. Although the joint constraints prefer mild dark energy dynamics and a little spatial curvature, they do not rule out dark energy being a cosmological constant and flat spatial hypersurfaces. We also add quasar angular size and H ii starburst galaxy measurements to the combined data set and find more restrictive constraints.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2017

( Hubble Space Telescope Hubble Space Telescope) detection of the millisecond pulsar J2124-3358 and its far-ultraviolet bow shock nebula

We observed the nearby millisecond pulsar J2124–3358 with the Hubble Space Telescope in broad far-UV (FUV) and optical filters. The pulsar is detected in both bands with fluxes F(1250–2000 Å) = (2.5 ± 0.3) × 10{sup −16} erg s{sup −1} cm{sup −2} and F(3800–6000 Å) = (6.4 ± 0.4) × 10{sup −17} erg s{sup −1} cm{sup −2}, which corresponds to luminosities of ≈5.8 × 10{sup 27} and 1.4 × 10{sup 27} erg s{sup −1}, for d = 410 pc and E(B − V) = 0.03. The optical-FUV spectrum can be described by a power-law model, f{sub ν}∝ν{sup α}, with slope α = 0.18–0.48 for a conservative range of color excess, E(B − V) = 0.01–0.08. Since a spectral flux rising with frequency is unusual for pulsar magnetospheric emission in this frequency range, it is possible that the spectrum is predominantly magnetospheric (power law with α < 0) in the optical, while it is dominated by thermal emission from the neutron star surface in the FUV. For a neutron star radius of 12 km, the surface temperature would be between 0.5 × 10{sup 5} and 2.1 × 10{sup 5} K for α ranging from −1 to 0, E(B − V) = 0.01–0.08, and d = 340–500 pc. In addition to the pulsar, the FUV images reveal extended emission that is spatially coincident with the known Hα bow shock, making PSR J2124–3358 the second pulsar (after PSR J0437−4715) with a bow shock detected in the FUV.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2018

Hubble Parameter and Baryon Acoustic Oscillation Measurement Constraints on the Hubble Constant, the Deviation from the Spatially Flat ΛCDM Model, the Deceleration–Acceleration Transition Redshift, and Spatial Curvature

We construct a complete collection of reliable Hubble parameter H(z) data to redshift z ≤ 2.36 and use them with the Gaussian Process approach to determine continuous H(z) functions for various data subsets. From these continuous H(z)'s, summarizing across the data subsets considered, we find H 0 ~ 67 ± 4 km s–1 Mpc–1, more consistent with the recent lower values observed using a variety of techniques. In most data subsets, we see a cosmological deceleration–acceleration transition at 2σ significance, with the data subsets transition redshifts varying over $0.33\lt {z}_{\mathrm{da}}\lt 1.0$ at 1σ significance. We discover that the flat-ΛCDM model is consistent with the H(z) data to a z of 1.5 to 2.0, depending on data subset considered, with 2σ deviations from flat-ΛCDM above this redshift range. Using the continuous H(z) with baryon acoustic oscillation distance-redshift observations, we constrain the current spatial curvature density parameter to be ${{\rm{\Omega }}}_{K0}=-0.03\pm 0.21$, consistent with a flat universe, but the large error bar does not rule out small values of spatial curvature that are now under debate.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

NASA NTRS1993

Hubble, bubble, toil and trouble: A reduced-order model based saga of the Hubble Space Telescope

Low-order control of the Hubble Space Telescope (HST) to improve pointing performance in the presence of flexible solar array disturbances is demonstarted in this paper. Our controller is a disturbance accommodating controller (DAC) based on a reduced-order model (ROM) controller with a disturbance estimator and a residual mode filter (RMF). We achieve the performance goals with a very low-order multichannel controller as compared to the various Solar Array Gain Augmentation (SAGA) schemes used at present.

Balas, Mark↗

DOE OSTI2017

A Hubble Space Telescope Survey for Novae in M87. II. Snuffing out the Maximum Magnitude–Rate of Decline Relation for Novae as a Non-standard Candle, and a Prediction of the Existence of Ultrafast Novae

The extensive grid of numerical simulations of nova eruptions from the work of Yaron et al. first predicted that some classical novae might significantly deviate from the Maximum Magnitude–Rate of Decline (MMRD) relation, which purports to characterize novae as standard candles. Kasliwal et al. have announced the observational detection of a new class of faint, fast classical novae in the Andromeda galaxy. These objects deviate strongly from the MMRD relationship, as predicted by Yaron et al. Recently, Shara et al. reported the first detections of faint, fast novae in M87. These previously overlooked objects are as common in the giant elliptical galaxy M87 as they are in the giant spiral M31; they comprise about 40% of all classical nova eruptions and greatly increase the observational scatter in the MMRD relation. We use the extensive grid of the nova simulations of Yaron et al. to identify the underlying causes of the existence of faint, fast novae. These are systems that have accreted, and can thus eject, only very low-mass envelopes, of the order of 10{sup −7}–10{sup −8} M {sub ⊙}, on massive white dwarfs. Such binaries include, but are not limited to, the recurrent novae. These same models predict the existence of ultrafast novae that display decline times, t {sub 2,} to be as short as five hours. We outline a strategy for their future detection.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS2004

Mothers of Invention: Hubble Engineers Push Robotic 'Evolution' to Save Telescope, Enable New Exploration

Robotic technology being developed out of necessity to keep the Hubble Space Telescope operating could also lead to new levels of man-machine team-work in deep-space exploration down the road-if it survives the near-term scramble for funding. Engineers here who have devoted their NASA careers to the concept of humans servicing the telescope in orbit are planning modifications to International Space Station (ISS) robots that would leave the humans on the ground. The work. forced by post-Columbia flight rules that killed a planned shuttle-servicing mission to Hubble, marks another step in the evolution of robot-partners for human space explorers. "Hubble has always been a pathfider for this agency," says Mike Weiss. Hubble deputy program manager technical. "When the space station was flown and assembled, Hubble was the pathfinder. not just for modularity, but for operations, for assembly techniques. Exploration is the next step. Things we're going to do on Hubble are going to be applied to exploration. It's not just putting a robot in space. It's operating a robot in space. It's adapting that robot to what needs to be done the next time you're up there."

Morring, Frank, Jr.↗

NASA NTRS2019

Lifetimes and Occurrence Rates of Dark Vortices on Neptune from 25 Years of Hubble Space Telescope Images

We scoured the full set of blue-wavelength Hubble Space Telescope images of Neptune, finding one additional dark spot in new Hubble data beyond those discovered in 1989, 1994, 1996, and 2015. We report the complete disappearance of the SDS-2015 dark spot, using new Hubble data taken on 2018 September 9–10, as part of the Outer Planet Atmospheres Legacy (OPAL) program. Overall, dark spots in the full Hubble data set have lifetimes of at least one to two years, and no more than six years. We modeled a set of dark spots randomly distributed in time over the latitude range on Neptune that is visible from Earth, finding that the cadence of archival Hubble images would have detected about 70% of these spots if their lifetimes are only one year, or about 85%–95% of simulated spots with lifetimes of two or more years. Based on the Hubble data set, we conclude that dark spots have average occurrence rates of one dark spot every four to six years. Many numerical models to date have simulated much shorter vortex lifetimes, so our findings provide constraints that may lead to improved understanding of Neptune’s wind field, stratification, and humidity.

Hsu, Andrew I.↗

DOE OSTI2022

Measurements of the Hubble Constant with a Two-rung Distance Ladder: Two Out of Three Ain’t Bad

Abstract The three-rung distance ladder, which calibrates Type Ia supernovae (SNe Ia) through stellar distances linked to geometric measurements, provides the highest precision direct measurement of the Hubble constant. In light of the Hubble tension, it is important to test the individual components of the distance ladder. For this purpose, we report a measurement of the Hubble constant from 35 extragalactic Cepheid hosts measured by the SH0ES team, using their distances and redshifts at cz ≤ 3300 km s −1 , instead of any more distant SNe Ia, to measure the Hubble flow. The Cepheid distances are calibrated geometrically in the Milky Way, NGC 4258, and the Large Magellanic Cloud. Peculiar velocities are a significant source of systematic uncertainty at z ∼ 0.01, and we present a formalism for both mitigating and quantifying their effects, making use of external reconstructions of the density and velocity fields in the nearby universe. We identify a significant source of uncertainty originating from different assumptions about the selection criteria of this sample, whether distance or redshift limited, as it was assembled over three decades. Modeling these assumptions yields central values ranging from H 0 = 71.7 to 76.4 km s −1 Mpc −1 . Combining the four best-fitting selection models yields H 0 = 72.9 − 2.2 + 2.4 as a fiducial result, at 2.4 σ tension with Planck. While SNe Ia are essential for a precise measurement of H 0 , unknown systematics in these supernovae are unlikely to be the source of the Hubble tension.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS2007

Hubble 2006: Science Year in Review

The 10 science articles selected for this years annual science report exemplify the range of Hubble research from the Solar System, across our Milky Way, and on to distant galaxies. The objects of study include a new feature on Jupiter, binaries in the Kuiper Belt, Cepheid variable stars, the Orion Nebula, distant transiting planets, lensing galaxies, active galactic nuclei, red-and-dead galaxies, and galactic outflows and jets. Each narrative strives to construct the readers understanding of the topics and issues, and to place the latest research in historical, as well as scientific, context. These essays reveal trends in the practice of astronomy. More powerful computers are permitting astronomers to study ever larger data sets, enabling the discovery of subtle effects and rare objects. (Two investigations created mosaic images that are among the largest produced to date.) Multiwavelength data sets from ground-based telescopes, as well as other great observatories Spitzer and Chandraare increasingly important for holistic interpretations of Hubble results. This yearbook also presents profiles of 12 individuals who work with Hubble, or Hubble data, on a daily basis. They are representative of the many students, scientists, engineers, and other professions who are proudly associated with Hubble. Their stories collectively communicate the excitement and reward of careers related to space science and technology.

Hubble space telescope↗

DOE OSTI2019

First Measurement of the Hubble Constant from a Dark Standard Siren using the Dark Energy Survey Galaxies and the LIGO/Virgo Binary–Black-hole Merger GW170814

We present a multi-messenger measurement of the Hubble constant H 0 using the binary–black-hole merger GW170814 as a standard siren, combined with a photometric redshift catalog from the Dark Energy Survey (DES). The luminosity distance is obtained from the gravitational wave signal detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO)/Virgo Collaboration (LVC) on 2017 August 14, and the redshift information is provided by the DES Year 3 data. Black hole mergers such as GW170814 are expected to lack bright electromagnetic emission to uniquely identify their host galaxies and build an object-by-object Hubble diagram. However, they are suitable for a statistical measurement, provided that a galaxy catalog of adequate depth and redshift completion is available. Here we present the first Hubble parameter measurement using a black hole merger. Our analysis results in , which is consistent with both SN Ia and cosmic microwave background measurements of the Hubble constant. The quoted 68% credible region comprises 60% of the uniform prior range [20, 140] km s−1 Mpc−1, and it depends on the assumed prior range. If we take a broader prior of [10, 220] km s−1 Mpc−1, we find (57% of the prior range). Although a weak constraint on the Hubble constant from a single event is expected using the dark siren method, a multifold increase in the LVC event rate is anticipated in the coming years and combinations of many sirens will lead to improved constraints on H 0.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

NASA NTRS1994

A measurement of the Hubble constant from the X-ray properties and the Sunyaev-Zel'dovich effect of Abell 2218

The distance of the cluster of galaxies Abell 2218, and hence the value of the Hubble constant, has been measured by comparing the X-ray properties and the Sunyaev-Zel'dovich effect of the cluster. The result for the Hubble constant is H(sub zero) = 65 +/- 25 km/s/MPC, where the error includes the random and systematic errors, combined in quadrature, and the largest contributions to the overall error come from systematic errors in the Sunyaev-Zel'dovich effect data and in the X-ray spectrum of the cluster. The X-ray and Sunyaev-Zel'dovich effect data are consistent with the same model for the intergalactic medium in Abell 2218 (an isothermal Beta-model with Beta is about 0.65 and cluster core radius about 1.0 min). A prevous report of a smaller Hubble constant, found by applying the same method on the same cluster, is shown to be based on a model for the cluster gas that is inconsistent with the Einstein IPC data. The present result for the Hubble constant is consistent with the value found earlier for the cluster Abell 665: by combining the results of the method for both clusters we conclude that the value of the Hubble constant is H(sub zero) = 55 +/- 17 km/s/MPC.

Birkinshaw, M.↗

NASA NTRS1998

Soft X-Ray Exposure Testing of FEP Teflon for the Hubble Space Telescope

The FEP Teflon (DuPont) multilayer insulation (MLI) thermal-control blanket material on the Hubble Space Telescope is degrading in the space environment. During the first Hubble servicing mission in 1993, after 3.6 years in low Earth orbit, aluminized and silvered FEP Teflon MLI thermal-control blanket materials were retrieved. These materials have been jointly analyzed by the NASA Lewis Research Center and the NASA Goddard Space Flight Center for degradation induced in the space environment (ref. 1). Solar-facing blanket materials were found to be embrittled with through-the-thickness cracking in the 5-mil FEP. During the second Hubble servicing mission in 1997, astronauts noticed that several blankets had large areas with tears. The torn FEP was curled up in some areas, exposing the underlying materials to the space environment. This tearing problem, and the associated curling up of torn areas, could lead to over-heating of the telescope and to particulate contamination. A Hubble Space Telescope MLI Failure Review Board was assembled by Goddard to investigate and identify the degradation mechanism of the FEP, to identify and characterize replacement materials, and to estimate the extent of damage at the time of the third servicing mission in 1999. A small piece of FEP retrieved during the second servicing mission is being evaluated by this failure review board along with materials from the first servicing mission. Since the first servicing mission, and as part of the failure review board, Lewis has been exposing FEP to soft x-rays to help determine the damage mechanisms of FEP in the space environment. Soft x-rays, which can penetrate into the bulk of FEP, are generated during solar flares and appear to be contributing to the degradation of the Hubble MLI.

deGroh, Kim K.↗