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  • Physics  (25)
  • US 1090  (25)
  • 1
    Online Resource
    Online Resource
    Comet 67P/Churyumov-Gerasimenko: the GIADA dust environment model of the Rosetta mission target
    EDP Sciences ; 2010
    In:  Astronomy & Astrophysics Vol. 522 ( 2010-11), p. A63-
    Details
    In: Astronomy & Astrophysics, EDP Sciences, Vol. 522 ( 2010-11), p. A63-
    Type of Medium: Online Resource
    ISSN: 0004-6361 , 1432-0746
    URL: Article
    DOI: 10.1051/0004-6361/201014928
    RVK:
    UA 1000
    RVK:
    US 1090
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2010
    detail.hit.zdb_id: 1458466-9
    SSG: 16,12
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  • 2
    Online Resource
    Online Resource
    Heliospheric modulation of the interstellar dust flow on to Earth
    EDP Sciences ; 2019
    In:  Astronomy & Astrophysics Vol. 621 ( 2019-1), p. A54-
    Details
    In: Astronomy & Astrophysics, EDP Sciences, Vol. 621 ( 2019-1), p. A54-
    Abstract: Aims. Based on measurements by the Ulysses spacecraft and high-resolution modelling of the motion of interstellar dust (ISD) through the heliosphere we predict the ISD flow in the inner planetary system and on to the Earth. This is the third paper in a series of three about the flow and filtering of the ISD. Methods. Micrometer- and sub-micrometer-sized dust particles are subject to solar gravity and radiation pressure as well as to interactions with the interplanetary magnetic field that result in a complex size-dependent flow pattern of ISD in the planetary system. With high-resolution dynamical modelling we study the time-resolved flux and mass distribution of ISD and assess the necessary requirements for detection of ISD near the Earth. Results. Along the Earth orbit the density, speed, and flow direction of ISD depend strongly on the Earth’s position and the size of the interstellar grains. A broad maximum of the ISD flux (~2 × 10 −4 m −2 s −1 of particles with radii ≳0.3 μ m) occurs in March when the Earth moves against the ISD flow. During this time period the relative speed with respect to the Earth is highest (~60 km s -1 ), whereas in September when the Earth moves with the ISD flow, both the flux and the speed are lowest (≲10 km s -1 ). The mean ISD mass flow on to the Earth is approximately 100 kg yr -1 with the highest flux of ~3.5 kg day -1 occurring for about 2 weeks close to the end of the year when the Earth passes near the narrow gravitational focus region of the incoming ISD flow, downstream from the Sun. The phase of the 22-year solar wind cycle has a strong effect on the number density and flow of sub-micrometer-sized ISD particles. During the years of maximum electromagnetic focussing (year 2031 +/− 3) there is a chance that ISD particles with sizes even below 0.1 μ m can reach the Earth. Conclusions. We demonstrate that ISD can be effectively detected, analysed, and even collected by space probes at 1 AU distance from the Sun.
    Type of Medium: Online Resource
    ISSN: 0004-6361 , 1432-0746
    URL: Article
    DOI: 10.1051/0004-6361/201832644
    RVK:
    UA 1000
    RVK:
    US 1090
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2019
    detail.hit.zdb_id: 1458466-9
    SSG: 16,12
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  • 3
    Online Resource
    Online Resource
    IMEM2: a meteoroid environment model for the inner solar system
    EDP Sciences ; 2019
    In:  Astronomy & Astrophysics Vol. 628 ( 2019-8), p. A109-
    Details
    In: Astronomy & Astrophysics, EDP Sciences, Vol. 628 ( 2019-8), p. A109-
    Abstract: Context. The interplanetary dust complex is currently understood to be largely the result of dust production from Jupiter-family comets, with contributions also from longer-period comets (Halley- and Oort-type) and collisionally produced asteroidal dust. Aims. Here we develop a dynamical model of the interplanetary dust cloud from these source populations in order to develop a risk and hazard assessment tool for interplanetary meteoroids in the inner solar system. Methods. The long-duration (1 Myr) integrations of dust grains from Jupiter-family and Halley-type comets and main belt asteroids were used to generate simulated distributions that were compared to COBE infrared data, meteor data, and the diameter distribution of lunar microcraters. This allowed the constraint of various model parameters. Results. We present here the first attempt at generating a model that can simultaneously describe these sets of observations. Extended collisional lifetimes are found to be necessary for larger (radius ≥ 150 μ m) particles. The observations are best fit with a differential size distribution that is steep (slope = 5) for radii ≥ 150 μ m, and shallower (slope = 2) for smaller particles. At the Earth the model results in ~ 90–98% Jupiter-family comet meteoroids, and small contributions from asteroidal and Halley-type comet particles. In COBE data we find an approximately 80% contribution from Jupiter-family comet meteoroids and 20% from asteroidal particles. The resulting flux at the Earth is mostly within a factor of about two to three of published measurements.
    Type of Medium: Online Resource
    ISSN: 0004-6361 , 1432-0746
    URL: Article
    DOI: 10.1051/0004-6361/201834892
    RVK:
    UA 1000
    RVK:
    US 1090
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2019
    detail.hit.zdb_id: 1458466-9
    SSG: 16,12
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  • 4
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    Online Resource
    The filtering of interstellar dust in the solar system
    EDP Sciences ; 2013
    In:  Astronomy & Astrophysics Vol. 552 ( 2013-4), p. A130-
    Details
    In: Astronomy & Astrophysics, EDP Sciences, Vol. 552 ( 2013-4), p. A130-
    Type of Medium: Online Resource
    ISSN: 0004-6361 , 1432-0746
    URL: Article
    DOI: 10.1051/0004-6361/201219609
    RVK:
    UA 1000
    RVK:
    US 1090
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2013
    detail.hit.zdb_id: 1458466-9
    SSG: 16,12
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  • 5
    Online Resource
    Online Resource
    A new look into the Helios dust experiment data: presence of interstellar dust inside the Earth's orbit
    EDP Sciences ; 2006
    In:  Astronomy & Astrophysics Vol. 448, No. 1 ( 2006-03), p. 243-252
    Details
    In: Astronomy & Astrophysics, EDP Sciences, Vol. 448, No. 1 ( 2006-03), p. 243-252
    Type of Medium: Online Resource
    ISSN: 0004-6361 , 1432-0746
    URL: Article
    DOI: 10.1051/0004-6361:20053909
    RVK:
    UA 1000
    RVK:
    US 1090
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2006
    detail.hit.zdb_id: 1458466-9
    SSG: 16,12
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  • 6
    Online Resource
    Online Resource
    CLASH-VLT: Abell S1063 : Cluster assembly history and spectroscopic catalogue
    EDP Sciences ; 2021
    In:  Astronomy & Astrophysics Vol. 656 ( 2021-12), p. A147-
    Details
    In: Astronomy & Astrophysics, EDP Sciences, Vol. 656 ( 2021-12), p. A147-
    Abstract: Context. The processes responsible for galaxy evolution in different environments as a function of galaxy mass remain heavily debated. Rich galaxy clusters are ideal laboratories in which to distinguish the role of environmental versus mass quenching because they consist of a full range of galaxies and environments. Aims. Using the CLASH-VLT survey, we assembled an unprecedentedly large sample of 1234 spectroscopically confirmed members in Abell S1063. We found a dynamically complex structure at ⟨ z cl ⟩ = 0.3457 with a velocity dispersion σ v = 1380 −32 +26 km s −1 . We investigated cluster environmental and dynamical effects by analysing the projected phase-space diagram and the orbits as a function of galaxy spectral properties. Methods. We classified cluster galaxies according to the presence and strength of the [OII] emission line, the strength of the H δ absorption line, and colours. We investigated the relation between the spectral classes of galaxies and their position in the projected phase-space diagram. We separately analysed red and blue galaxy orbits. By correlating the observed positions and velocities with the projected phase-space constructed from simulations, we constrained the accretion redshift of galaxies with different spectral types. Results. Passive galaxies are mainly located in the virialised region, while emission-line galaxies lie beyond r 200 and are accreted into the cluster at a later time. Emission-line and post-starburst galaxies show an asymmetric distribution in projected phase-space within r 200 ; emission-line galaxies are prominent at Δ v / σ  ≲ −1.5 and post-starburst galaxies at Δ v / σ  ≳ 1.5, suggesting that backsplash galaxies lie at high positive velocities. We find that low-mass passive galaxies are accreted into the cluster before high-mass galaxies. This suggests that we observe as passives only the low-mass galaxies that are accreted early into the cluster as blue galaxies. They had the time to quench their star formation. We also find that red galaxies move on more radial orbits than blue galaxies. This can be explained if infalling galaxies can remain blue by moving on tangential orbits.
    Type of Medium: Online Resource
    ISSN: 0004-6361 , 1432-0746
    URL: Article
    DOI: 10.1051/0004-6361/202142168
    RVK:
    UA 1000
    RVK:
    US 1090
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2021
    detail.hit.zdb_id: 1458466-9
    SSG: 16,12
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  • 7
    Online Resource
    Online Resource
    Overview of the Instrumentation for the Dark Energy Spectroscopic Instrument
    American Astronomical Society ; 2022
    In:  The Astronomical Journal Vol. 164, No. 5 ( 2022-11-01), p. 207-
    Details
    In: The Astronomical Journal, American Astronomical Society, Vol. 164, No. 5 ( 2022-11-01), p. 207-
    Abstract: The Dark Energy Spectroscopic Instrument (DESI) embarked on an ambitious 5 yr survey in 2021 May to explore the nature of dark energy with spectroscopic measurements of 40 million galaxies and quasars. DESI will determine precise redshifts and employ the baryon acoustic oscillation method to measure distances from the nearby universe to beyond redshift z 〉 3.5, and employ redshift space distortions to measure the growth of structure and probe potential modifications to general relativity. We describe the significant instrumentation we developed to conduct the DESI survey. This includes: a wide-field, 3.°2 diameter prime-focus corrector; a focal plane system with 5020 fiber positioners on the 0.812 m diameter, aspheric focal surface; 10 continuous, high-efficiency fiber cable bundles that connect the focal plane to the spectrographs; and 10 identical spectrographs. Each spectrograph employs a pair of dichroics to split the light into three channels that together record the light from 360–980 nm with a spectral resolution that ranges from 2000–5000. We describe the science requirements, their connection to the technical requirements, the management of the project, and interfaces between subsystems. DESI was installed at the 4 m Mayall Telescope at Kitt Peak National Observatory and has achieved all of its performance goals. Some performance highlights include an rms positioner accuracy of better than 0.″1 and a median signal-to-noise ratio of 7 of the [O ii ] doublet at 8 × 10 −17 erg s −1 cm −2 in 1000 s for galaxies at z = 1.4–1.6. We conclude with additional highlights from the on-sky validation and commissioning, key successes, and lessons learned.
    Type of Medium: Online Resource
    ISSN: 0004-6256 , 1538-3881
    URL: Article
    DOI: 10.3847/1538-3881/ac882b
    RVK:
    US 1090
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2022
    detail.hit.zdb_id: 2207625-6
    detail.hit.zdb_id: 2003104-X
    SSG: 16,12
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  • 8
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    Online Resource
    Photometric Redshifts for Next-Generation Surveys
    Annual Reviews ; 2022
    In:  Annual Review of Astronomy and Astrophysics Vol. 60, No. 1 ( 2022-08-18), p. 363-414
    Details
    In: Annual Review of Astronomy and Astrophysics, Annual Reviews, Vol. 60, No. 1 ( 2022-08-18), p. 363-414
    Abstract: Photometric redshifts are essential in studies of both galaxy evolution and cosmology, as they enable analyses of objects too numerous or faint for spectroscopy. The Rubin Observatory, Euclid, and Roman Space Telescope will soon provide a new generation of imaging surveys with unprecedented area coverage, wavelength range, and depth. To take full advantage of these data sets, further progress in photometric redshift methods is needed. In this review, we focus on the greatest common challenges and prospects for improvement in applications of photometric redshifts to the next generation of surveys: ▪ Gains in performance (i.e., the precision of redshift estimates for individual galaxies) could greatly enhance studies of galaxy evolution and some probes of cosmology. ▪ Improvements in characterization (i.e., the accurate recovery of redshift distributions of galaxies in the presence of uncertainty on individual redshifts) are urgently needed for cosmological measurements with next-generation surveys. To achieve both of these goals, improvements in the scope and treatment of the samples of spectroscopic redshifts that make high-fidelity photometric redshifts possible will also be needed. For the full potential of the next generation of surveys to be reached, the characterization of redshift distributions must improve by roughly an order of magnitude compared with the current state of the art, requiring progress on a wide variety of fronts. We conclude by presenting a speculative evaluation of how photometric redshift methods and the collection of the necessary spectroscopic samples may improve by the time near-future surveys are completed.
    Type of Medium: Online Resource
    ISSN: 0066-4146 , 1545-4282
    URL: Issue
    URL: Article
    DOI: 10.1146/astro.2022.60.issue-1
    DOI: 10.1146/annurev-astro-032122-014611
    RVK:
    US 1090
    Language: English
    Publisher: Annual Reviews
    Publication Date: 2022
    detail.hit.zdb_id: 2160505-1
    detail.hit.zdb_id: 2010305-0
    SSG: 16,12
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  • 9
    Online Resource
    Online Resource
    Helios spacecraft data revisited: detection of cometary meteoroid trails by following in situ dust impacts
    EDP Sciences ; 2020
    In:  Astronomy & Astrophysics Vol. 643 ( 2020-11), p. A96-
    Details
    In: Astronomy & Astrophysics, EDP Sciences, Vol. 643 ( 2020-11), p. A96-
    Abstract: Context. Cometary meteoroid trails exist in the vicinity of comets, forming a fine structure of the interplanetary dust cloud. The trails consist predominantly of the largest cometary particles (with sizes of approximately 0.1 mm–1 cm), which are ejected at low speeds and remain very close to the comet orbit for several revolutions around the Sun. In the 1970s, two Helios spacecraft were launched towards the inner Solar System. The spacecraft were equipped with in situ dust sensors which measured the distribution of interplanetary dust in the inner Solar System for the first time. Recently, when re-analysing the Helios data, a clustering of seven impacts was found, detected by Helios in a very narrow region of space at a true anomaly angle of 135 ± 1°, which the authors considered as potential cometary trail particles. However, at the time, this hypothesis could not be studied further. Aims. We re-analyse these candidate cometary trail particles in the Helios dust data to investigate the possibility that some or all of them indeed originate from cometary trails and we constrain their source comets. Methods. The Interplanetary Meteoroid Environment for eXploration (IMEX) dust streams in space model is a new and recently published universal model for cometary meteoroid streams in the inner Solar System. We use IMEX to study the traverses of cometary trails made by Helios. Results. During ten revolutions around the Sun, the Helios spacecraft intersected 13 cometary trails. For the majority of these traverses the predicted dust fluxes are very low. In the narrow region of space where Helios detected the candidate dust particles, the spacecraft repeatedly traversed the trails of comets 45P/Honda-Mrkos-Pajdušáková and 72P/Denning-Fujikawa with relatively high predicted dust fluxes. The analysis of the detection times and particle impact directions shows that four detected particles are compatible with an origin from these two comets. By combining measurements and simulations we find a dust spatial density in these trails of approximately 10 −8 –10 −7 m −3 . Conclusions. The identification of potential cometary trail particles in the Helios data greatly benefited from the clustering of trail traverses in a rather narrow region of space. The in situ detection and analysis of meteoroid trail particles which can be traced back to their source bodies by spacecraft-based dust analysers provides a new opportunity for remote compositional analysis of comets and asteroids without the necessity to fly a spacecraft to or even land on those celestial bodies. This provides new science opportunities for future missions like DESTINY + (Demonstration and Experiment of Space Technology for INterplanetary voYage with Phaethon fLyby and dUst Science), Europa Clipper, and the Interstellar Mapping and Acceleration Probe.
    Type of Medium: Online Resource
    ISSN: 0004-6361 , 1432-0746
    URL: Article
    DOI: 10.1051/0004-6361/202038935
    RVK:
    UA 1000
    RVK:
    US 1090
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2020
    detail.hit.zdb_id: 1458466-9
    SSG: 16,12
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  • 10
    Online Resource
    Online Resource
    Dark Energy Survey Year 3 Results: Galaxy mock catalogs for BAO analysis
    EDP Sciences ; 2021
    In:  Astronomy & Astrophysics Vol. 656 ( 2021-12), p. A106-
    Details
    In: Astronomy & Astrophysics, EDP Sciences, Vol. 656 ( 2021-12), p. A106-
    Abstract: The calibration and validation of scientific analysis in simulations is a fundamental tool to ensure unbiased and robust results in observational cosmology. In particular, mock galaxy catalogs are a crucial resource to achieve these goals in the measurement of baryon acoustic oscillation (BAO) in the clustering of galaxies. Here we present a set of 1952 galaxy mock catalogs designed to mimic the Dark Energy Survey Year 3 BAO sample over its full photometric redshift range 0.6  〈   z photo   〈  1.1. The mocks are based upon 488 ICE-COLA fast N -body simulations of full-sky light cones and were created by populating halos with galaxies, using a hybrid halo occupation distribution – halo abundance matching model. This model has ten free parameters, which were determined, for the first time, using an automatic likelihood minimization procedure. We also introduced a novel technique to assign photometric redshift for simulated galaxies, following a two-dimensional probability distribution with VIMOS Public Extragalactic Redshift Survey data. The calibration was designed to match the observed abundance of galaxies as a function of photometric redshift, the distribution of photometric redshift errors, and the clustering amplitude on scales smaller than those used for BAO measurements. An exhaustive analysis was done to ensure that the mocks reproduce the input properties. Finally, mocks were tested by comparing the angular correlation function w ( θ ), angular power spectrum C ℓ , and projected clustering ξ p ( r ⊥ ) to theoretical predictions and data. The impact of volume replication in the estimate of the covariance is also investigated. The success in accurately reproducing the photometric redshift uncertainties and the galaxy clustering as a function of redshift render this mock creation pipeline as a benchmark for future analyses of photometric galaxy surveys.
    Type of Medium: Online Resource
    ISSN: 0004-6361 , 1432-0746
    URL: Article
    DOI: 10.1051/0004-6361/202141744
    RVK:
    UA 1000
    RVK:
    US 1090
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2021
    detail.hit.zdb_id: 1458466-9
    SSG: 16,12
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