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Parameter Estimation for Compact Binary Coalescence Signals with the First Generation Gravitational-Wave Detector Network (2013)

Grunewald, S. ; Roux, A. Le ; Morgado, N. ; [weitere]

In: Other Sources

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Publikationsdatum: 2019-07-13

Beschreibung: Compact binary systems with neutron stars or black holes are one of the most promising sources for ground-based gravitational-wave detectors. Gravitational radiation encodes rich information about source physics; thus parameter estimation and model selection are crucial analysis steps for any detection candidate events. Detailed models of the anticipated waveforms enable inference on several parameters, such as component masses, spins, sky location and distance, that are essential for new astrophysical studies of these sources. However, accurate measurements of these parameters and discrimination of models describing the underlying physics are complicated by artifacts in the data, uncertainties in the waveform models and in the calibration of the detectors. Here we report such measurements on a selection of simulated signals added either in hardware or software to the data collected by the two LIGO instruments and the Virgo detector during their most recent joint science run, including a blind injection where the signal was not initially revealed to the collaboration. We exemplify the ability to extract information about the source physics on signals that cover the neutron-star and black-hole binary parameter space over the component mass range 1M25M and the full range of spin parameters. The cases reported in this study provide a snapshot of the status of parameter estimation in preparation for the operation of advanced detectors.

Schlagwort(e): Astrophysics

Materialart: GSFC-E-DAA-TN12729 , Physical Review D (ISSN 2470-0010) (e-ISSN 2470-0029); 88; 062001

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First All-Sky Search for Continuous Gravitational Waves from Unknown Sources in Binary Systems (2014)

Straniero, N. ; Wittel, H. ; Frasca, S. ; [weitere]

In: Other Sources

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Publikationsdatum: 2019-07-13

Beschreibung: We present the first results of an all-sky search for continuous gravitational waves from unknown spinning neutron stars in binary systems using LIGO and Virgo data. Using a specially developed analysis program, the TwoSpect algorithm, the search was carried out on data from the sixth LIGO science run and the second and third Virgo science runs. The search covers a range of frequencies from 20 Hz to 520 Hz, a range of orbital periods from 2 to 2,254 h and a frequency- and period-dependent range of frequency modulation depths from 0.277 to 100 mHz. This corresponds to a range of projected semimajor axes of the orbit from 0.6 10(exp 3) ls to 6,500 ls assuming the orbit of the binary is circular. While no plausible candidate gravitational wave events survive the pipeline, upper limits are set on the analyzed data. The most sensitive 95% confidence upper limit obtained on gravitational wave strain is 2.3 10(exp 24) at 217 Hz, assuming the source waves are circularly polarized. Although this search has been optimized for circular binary orbits, the upper limits obtained remain valid for orbital eccentricities as large as 0.9. In addition, upper limits are placed on continuous gravitational wave emission from the low-mass x-ray binary Scorpius X-1 between 20 Hz and 57.25 Hz.

Schlagwort(e): Astrophysics

Materialart: GSFC-E-DAA-TN22620 , Physical Review D (ISSN 0031-899X) (e-ISSN 1536-6065); 90; 6; 062010

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A Super-Jupiter Orbiting A Late-Type Star: A Refined Analysis of Microlensing Event OGLE-2012-BLG-0406 (2014)

Kane, S. R. ; Yee, J. C. ; Greenhill, J. ; [weitere]

In: Other Sources

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Publikationsdatum: 2019-07-13

Beschreibung: We present a detailed analysis of survey and follow-up observations of microlensing event OGLE-2012-BLG-0406 based on data obtained from 10 different observatories. Intensive coverage of the light curve, especially the perturbation part, allowed us to accurately measure the parallax effect and lens orbital motion. Combining our measurement of the lens parallax with the angular Einstein radius determined from finite-source effects, we estimate the physical parameters of the lens system. We find that the event was caused by a 2.73 plus or minus 0.43 M (sub J) planet orbiting a 0.44 plus or minus 0.07 solar mass early M-type star. The distance to the lens is 4.97 plus or minus 0.29 kpc and the projected separation between the host star and its planet at the time of the event is 3.45 plus or minus 0.26 AU. We find that the additional coverage provided by follow-up observations, especially during the planetary perturbation, leads to a more accurate determination of the physical parameters of the lens.

Schlagwort(e): Astronomy; Astrophysics

Materialart: GSFC-E-DAA-TN15082 , Astrophysical Journal (ISSN 2041-8205) (e-ISSN 2041-8213); 782; 1; 48

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Curiosity at Gale Crater, Mars: Characterization and Analysis of the Rocknest Sand Shadow (2013)

Mahaffy, P. ; Farmer, J. D. ; Stolper, E. M. ; [weitere]

In: CASI

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Publikationsdatum: 2014-11-22

Beschreibung: The Rocknest aeolian deposit is similar to aeolian features analyzed by the Mars Exploration Rovers (MER) Spirit and Opportunity. The fraction of sand 〈150 micron in size contains approx. 55% crystalline material consistent with a basaltic heritage, and approx. 45% X-ray amorphous material. The amorphous component of Rocknest is Fe-rich and Si-poor, and is the host of the volatiles (H2O, O2, SO2, CO2, and Cl) detected by the Surface Analysis at Mars (SAM) instrument and of the fine-grained nanophase oxide (npOx) component first described from basaltic soils analyzed by MER. The similarity between soils and aeolian materials analyzed at Gusev crater, Meridiani Planum and Gale crater implies locally sourced, globally similar basaltic materials, or globally and regionally sourced basaltic components deposited locally at all three locations.

Schlagwort(e): Lunar and Planetary Science and Exploration

Materialart: ARC-E-DAA-TN11260

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5

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Herschel-ATLAS: The Angular Correlation Function of Submillimetre Galaxies at High and Low Redshift (2010)

Dariush, A. ; Buttiglione, S. ; Benford, D. ; [weitere]

In: Other Sources

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Publikationsdatum: 2018-06-06

Beschreibung: We present measurements of the angular correlation function of galaxies selected from the first field of the H-ATLAS survey. Careful removal of the background from galactic cirrus is essential, and currently dominates the uncertainty in our measurements. For our 250 micrometer-selected sample we detect no significant clustering, consistent with the expectation that the 250 pm-selected sources are mostly normal galaxies at z 〈 or equal to 1. For our 350 micrometer and 500 micrometer-selected samples we detect relatively strong clustering with correlation amplitudes A of 0.2 and 1.2 at 1', but with relatively large uncertainties. For samples which preferentially select high redshift galaxies at z approx. 2-3 we detect significant strong clustering, leading to an estimate of r(0) approx. 7-11/h Mpc. The slope of our clustering measurements is very steep. delta approx. 2. The measurements are consistent with the idea that sub-mm sources consist of a low redshift population of normal galaxies and a high redshift population of highly clustered star-bursting galaxies.

Schlagwort(e): Astronomy

Materialart: Astronomy and Astrophysics: Special Feature; Volume 518

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Fermi-LAT Detection of Gravitational Lens Delayed Gamma-Ray Flares from Blazar B0218+357 (2014)

Chekhtman, A. ; Amin, M. A. ; Smith, A. W. ; [weitere]

In: CASI

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Publikationsdatum: 2019-07-13

Beschreibung: Using data from the Fermi Large Area Telescope (LAT), we report the first clear gamma-ray measurement of a delay between flares from the gravitationally lensed images of a blazar. The delay was detected in B0218+357, a known double-image lensed system, during a period of enhanced gamma-ray activity with peak fluxes consistently observed to reach greater than 20-50 times its previous average flux. An auto-correlation function analysis identified a delay in the gamma-ray data of 11.46 plus or minus 0.16 days (1 sigma) that is approximately 1 day greater than previous radio measurements. Considering that it is beyond the capabilities of the LAT to spatially resolve the two images, we nevertheless decomposed individual sequences of superposing gamma-ray flares/delayed emissions. In three such approximately 8-10 day-long sequences within an approximately 4-month span, considering confusion due to overlapping flaring emission and flux measurement uncertainties, we found flux ratios consistent with approximately 1, thus systematically smaller than those from radio observations. During the first, best-defined flare, the delayed emission was detailed with a Fermi pointing, and we observed flux doubling timescales of approximately 3-6 hours implying as well extremely compact gamma-ray emitting regions.

Schlagwort(e): Astronomy; Astrophysics

Materialart: GSFC-E-DAA-TN21851 , The Astrophysical Journal Letter (ISSN 1538-4357); 782; 2; L14

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7

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Thermal mapping, geothermal source location, natural effluents and plant stress in the Mediterranean coast of Spain (1980)

Miralles, D. J. M. ; Perlado, D. J. P. ; Labrandero, D. J. L. ; [weitere]

In: CASI

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Publikationsdatum: 2019-06-28

Beschreibung: Although no significant results were achieved during the report period, research continues. A sample of imagery showing thermal inertia and temperature differences over the northeastern United States and Europe was received. The project coordinator attended a TELLUS Project meeting in Ispra, Italy at which general guidelines for the future were established and the quality of the data received was discussed.

Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING

Materialart: E81-10119 , NASA-CR-164113 , PR-3

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Overview of a Preliminary Destination Mission Concept for a Human Orbital Mission to the Martial Moons (2012)

Mazanek, D. D. ; Daugherty, K. J. ; Castillo-Rogez, J. C. ; [weitere]

In: CASI

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Publikationsdatum: 2019-07-13

Beschreibung: The National Aeronautics and Space Administration s Human Spaceflight Architecture Team (HAT) has been developing a preliminary Destination Mission Concept (DMC) to assess how a human orbital mission to one or both of the Martian moons, Phobos and Deimos, might be conducted as a follow-on to a human mission to a near-Earth asteroid (NEA) and as a possible preliminary step prior to a human landing on Mars. The HAT Mars-Phobos-Deimos (MPD) mission also permits the teleoperation of robotic systems by the crew while in the Mars system. The DMC development activity provides an initial effort to identify the science and exploration objectives and investigate the capabilities and operations concepts required for a human orbital mission to the Mars system. In addition, the MPD Team identified potential synergistic opportunities via prior exploration of other destinations currently under consideration.

Schlagwort(e): Lunar and Planetary Science and Exploration

Materialart: JSC-CN-26565 , Concepts and Approaches for Mars Exploration; Jun 12, 2012 - Jun 14, 2012; Houston, TX; United States

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Characterizing the Phyllosilicate Component of the Sheepbed Mudstone in Gale Crater, Mars Using Laboratory XRD and EGA (2014)

Ming, D. W. ; Sutter, B. ; Bristow, T. F. ; [weitere]

In: CASI

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Publikationsdatum: 2019-07-13

Beschreibung: The Curiosity rover investigated the mineralogy of the Sheepbed mudstone member of the Yellowknife Bay formation in Gale crater. Data from the Chemistry and Mineralogy (CheMin) X-ray diffractometer (XRD) helped identify phyllosilicates in the two drilled samples, John Klein and Cumberland. These patterns showed peaks at low angles, consistent with (001) peaks in 2:1 swelling phyllosilicates [1]. Evolved gas analyses (EGA) by the Sample Analysis at Mars (SAM) instrument of these samples confirmed the presence of phyllosilicates through the release of H2O at high temperatures, consistent with dehydroxylation of octahedral OH in phyllosilicates [2]. CheMin data for the phyllosilicates at John Klein and Cumberland show that they are structurally similar in that their (02l) peaks are near 22.5 deg 2theta, suggesting both samples contain trioctahedral 2:1 phyllosilicates [1]. However, the positions of the (001) peaks differ: the phyllosilicate at John Klein has its (001) peak at 10 Angstroms, whereas the phyllosilicate at Cumberland has an (001) peak at 14 Angstroms. Such differences in (001) dspacings can be ascribed to the type of cation in the interlayer site [3]. For example, large monovalent cations (e.g., K(+)) have low hydration energies and readily lose their H2O of hydration, whereas small divalent cations (e.g., Mg(2+)) have high energies of hydration and retain H2O in the phyllosilicate interlayers [3,4]. The goal of this study is to determine whether differences in the interlayer cation composition can explain the CheMin data from John Klein and Cumberland and to use this knowledge to better understand phyllosilicate formation mechanisms.

Schlagwort(e): Lunar and Planetary Science and Exploration

Materialart: JSC-CN-30371 , Lunar and Planetary Science Conference; Mar 17, 2014 - Mar 21, 2014; The Woodlands, TX; United States

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High Degree and Order Gravity Fields of the Moon Derived from GRAIL Data (2012)

Loomis, B. D. ; Chinn, D. S. ; Lemoine, F. G. ; [weitere]

In: CASI

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Publikationsdatum: 2019-07-19

Beschreibung: The Gravity Recovery and Interior Laboratory (GRAIL) spacecraft conducted the mapping of the gravity field of the Moon from March 1, 2012 to May 29, 2012. The twin spacecraft acquired highly precise K Band range-rate (KBRR) intersatellite ranging data and Deep Space Network (DSN) data during this prime mission phase from altitudes of 15 to 75 km above the lunar surface over three lunar months. We have processed these data using the NASA GSFC GEODYN orbit determination and geodetic parameter estimation program, and we have determined gravity fields up to degree and order 420 in spherical harmonics. The new gravity solutions show improved correlations with LOLA-derived topography to high degree and order and resolve many lunar features in the geopotential with a resolution of less than 30 km, including for example the central peak of the crater Tycho. We discuss the methodology used for the processing of the GRAIL data, the quality of the orbit determination on the GRAIL satellites and the derivation of the solutions, and their evaluation with independent data, including Lunar Prospector. We show that with these new GRAIL gravity solutions, we can now fit the low altitude, extended mission Lunar Prospector tracking data better than with any previous gravity model that included the LP data.

Schlagwort(e): Space Sciences (General)

Materialart: GSFC.ABS.7399.2012 , American Geophysical Union Meeting; Dec 03, 2012 - Dec 07, 2012; San Francisco, CA; United States

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