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Green Bank Observatory:NSF Releases Draft Environmental Impact Statement（图）
Green Bank Observatory NSF Draft Environmental Impact
2017/12/19
On Nov. 8, 2017, the National Science Foundation (NSF) published the Draft Environmental Impact Statement (DEIS) for the Green Bank Observatory in Green Bank, West Virginia.NSF prepared the DEIS in co...
Statement on impact of Hurricane Maria on Arecibo Observatory（图）
Hurricane Maria Arecibo Observatory
2017/10/24
While Arecibo Observatory suffered some damage, initial indications are that the damage was less severe than might have been expected from a storm of the magnitude of Hurricane Maria. Operations at th...
Low-speed impact simulations into regolith in support of asteroid sampling mechanism design I:Comparison with 1-g experiments
Asteroids Surfaces Collisional physics Granular material Sampling mechanism Geological processes Regoliths
2015/12/25
This study is carried out in the framework of sample-return missions to asteroids that use a low-speed projectile as the primary component of its sampling mechanism (e.g., JAXA’s Hayabusa and Hayabusa...
Numerically simulating impact disruptions of cohesive glass bead agglomerates using the soft-sphere discrete element method
Asteroids, Surfaces Collisional physics Geological processes Regoliths
2015/12/25
We present our implementation of cohesion in the parallel N-body code pkdgrav in order to model small bodies that are not fully monolithic but that have at least some degree of cohesion. Small bodies ...
A comparison between rubble-pile and monolithic targets in impact simulations:Application to asteroid satellites and family size distributions
Asteroids Collisional physics Impact processes Satellites, General
2015/12/25
Collisions are a fundamental process in the creation of asteroid families and in satellite formation. For this reason, understanding the outcome of impacts is fundamental to the accurate modeling of t...
Insights into collisional physics may be obtained by studying the asteroid belt, where large-scale collisions produced groups of asteroid fragments with similar orbits and spectra known as the asteroi...
Pre-heating by pre-virialization and its impact on galaxy formation
dark matter large-scale structure of the universe
2014/12/24
We use recent observations of the H i mass function to constrain galaxy formation. The data conflict with the standard model where most of the gas in a low-mass dark matter halo is assumed to settle i...
Submillimeter Wave Astronomy Satellite observations of Comet 9P/Tempel 1 and Deep Impact
Comet Tempel-1 Radiative Transfer Radio Observations Comets
2014/12/23
On 4 July 2005 at 5:52 UT the Deep Impact mission successfully completed its goal to hit the nucleus of 9P/Tempel 1 with an impactor, forming a crater on the nucleus and ejecting material into the com...
USING 21 cm ABSORPTION IN SMALL IMPACT PARAMETER GALAXY-QUASAR PAIRS TO PROBE LOW-REDSHIFT DAMPED AND SUB-DAMPED Ly alpha SYSTEMS
low-redshift damped Lyα (DLA) sub-DLA quasar absorbers
2014/12/20
To search for low-redshift damped Lyα (DLA) and sub-DLA quasar absorbers, we have conducted a 21 cm absorption survey of radio-loud quasars at small impact parameters to foreground galaxies selected f...
Galactic Bulge Feedback and its Impact on Galaxy Evolution
galactic feedback hydrodynamics intergalactic medium Intestellar Medium supernova remnants X-ray
2014/12/9
Galactic bulges of early-type spirals and elliptical galaxies comprise primarily old stars, which account for more than half of the total stellar mass in the local Universe. These stars collectively g...
Measures of Star Formation Rates within Galaxies: the Impact of Diffuse Stellar Populations
galaxies:ISM ISM:structure infrared:galaxies infrared:ISM H{\sc ii} regions
2014/12/9
Thanks to the {\it Spitzer Space Telescope}, the infrared (IR) emission have been better studied in the past decades, as well as its relations to star formation rates (SFR) and the calibrations of IR ...
The HARPS search for southern extra-solar planets. XXXI. Magnetic activity cycles in solar-type stars: statistics and impact on precise radial velocities
Planetary systems – Stars: activity – Stars: chromospheres – Line: profi les – Techniques: radial velocities – Techniques:spectroscopic
2011/10/17
Context. Searching for extrasolar planets through radial velocity measurements relies on the stability of stellar photospheres. Aims. We aim at characterizing the statistical properties of magnetic ac...
Modelling interaction of relativistic and non-relativistic winds in binary system PSR B1259-63/SS2883 - II. Impact of magnetization and anisotropy of the pulsar wind
HD – shock waves - pulsars: binaries
2011/10/19
In this paper, we present a numerical study of the properties of the flow produced by the collision of a magnetized anisotropic pulsar wind with its environment in binary system. We compare the impact...
Measurement requirements for a near-Earth asteroid impact mitigation demonstration mission
Near-Earth Asteroids Impact Mitigation Spacecraft Missions
2011/10/12
A concept for an Impact Mitigation Preparation Mission, called Don Quijote, is to send two spacecraft to a Near-Earth Asteroid (NEA): an Orbiter and an Impactor. The Impactor collides with the asteroi...
The impact of a stochastic gravitational-wave background on pulsar timing parameters
impact stochastic gravitational-wave background timing parameters
2011/10/12
Gravitational waves are predicted by Einstein's theory of general relativity as well as other theories of gravity. The rotational stability of the fastest pulsars means that timing of an array of thes...