Suppressing cluster cooling flows by self-regulated heating from a spatially distributed population of active galactic nuclei     

Adi Nusser  Joseph Silk  Arif Babul 《Monthly notices of the Royal Astronomical Society》2006,373(2):739-746

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Numerical action reconstruction of the dynamical history of dark matter haloes in N-body simulations     

Steven D. Phelps  Vincent Desjacques†  Adi Nusser  Edward J. Shaya 《Monthly notices of the Royal Astronomical Society》2006,370(3):1361-1371

We test the ability of the numerical action method (NAM) to recover the individual orbit histories of mass tracers in an expanding universe, given the masses and redshift-space coordinates at the present epoch. The mass tracers are represented by dark matter (DM) haloes identified in a region of radius  26  h ⁻¹ Mpc  of a high-resolution N -body simulation of the standard Λ cold dark matter (CDM) cosmology. Since previous tests of NAM at this scale have traced the underlying distribution of DM particles rather than extended haloes, our study offers an assessment of the accuracy of NAM in a scenario which more closely approximates the complex dynamics of actual galaxy haloes. We show that NAM can recover the present-day halo distances with typical distance errors of less than 3 per cent and radial peculiar velocities with a dispersion of  ∼130 km s⁻¹  . The accuracy of individual orbit reconstructions was limited by the inability of NAM, in some instances, to correctly model the positions of haloes at early times solely on the basis of the redshifts, angular positions and masses of the haloes at the present epoch. Improvements in the quality of NAM reconstructions may be possible using the present-day three-dimensional halo velocities and distances to further constrain the dynamics. This velocity data is expected to become available for nearby galaxies in the coming generations of observations by Space Interferometry Mission ( SIM ) and Global Astrometric Interferometer for Astrophysics ( GAIA ).  相似文献   

Redshift distortions in one-dimensional power spectra     

Vincent Desjacques  Adi Nusser 《Monthly notices of the Royal Astronomical Society》2004,351(4):1395-1400

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Oxygen Consumption in Permeable and Cohesive Sediments of the Gulf of Aqaba     

Valeria Boyko  Adi Torfstein  Alexey KamyshnyJr. 《Aquatic Geochemistry》2018,24(3):165-193

Oxygen profiles were measured in the sediments of the Gulf of Aqaba (Red Sea), an oligotrophic marine system affected by episodic seasonal flash floods and intense aeolian dry deposition. Sediment cores were retrieved from shallow (15–45 m), intermediate (250–561 m) and deep (700 m) water sites of south–north and east–west transects. Dissolved oxygen concentrations were measured simultaneously by using microelectrodes and microoptodes immediately after sampling and after transportation. Oxygen penetration depths were found to increase from 2 to 5 mm at the shallow water sites with sandy permeable sediments to 10–21 mm at the deeper sites with cohesive muddy sediments. This increase corresponds to decrease in oxygen diffusive fluxes at the sediment–water interface and oxygen consumption rates with depth. Oxygen consumption rates exhibit local maxima at the oxic–anoxic sediment boundary, which may be attributed to oxygen reduction coupled to oxidation of dissolved Fe(II) and Mn(II) at deep and intermediate water sites and of hydrogen sulfide at shallow water sites. Microelectrodes and microoptodes measurements of cohesive sediments from deep and intermediate water sites yielded similar results. By comparison, the microoptodes displayed more robust measurements than microelectrodes in sandy near-shore sediments. This was attributed to their flexible fiber structure that is less likely to break or to abruptly displace sand particles. After transportation of sediment cores from Eilat to Beer Sheva followed by ≤?24-h storage, no changes in oxygen fluxes and consumption rates were detected.  相似文献   

Searching for neutrinos from WIMP annihilations in the Galactic stellar disc     

Zacharia Myers  Adi Nusser 《Monthly notices of the Royal Astronomical Society》2008,387(4):1712-1718

Weakly interacting massive particles (WIMPs) are a viable candidate for the relic abundance of dark matter (DM) produced in the early universe. So far, WIMPs have eluded direct detection through interactions with baryonic matter. Neutrino emission from accumulated WIMP annihilations in the solar core has been proposed as a signature of DM, but has not yet been detected. These null results may be due to small-scale DM density fluctuations in the halo with the density of our local region being lower than the average  (∼0.3 GeV cm⁻³)  . However, the accumulated neutrino signal from WIMP annihilations in the Galactic stellar disc would be insensitive to local density variations. Inside the disc, DM can be captured by stars causing an enhanced annihilation rate and therefore a potentially higher neutrino flux than what would be observed from elsewhere in the halo. We estimate a neutrino flux from the WIMP annihilations in the stellar disc to be enhanced by more than an order of magnitude compared to the neutrino fluxes from the halo. We offer a conservative estimate for this enhanced flux, based on the WIMP–nucleon cross-sections obtained from direct-detection experiments by assuming a density of  ∼0.3 GeV cm⁻³  for the local DM. We also compare the detectability of these fluxes with a signal of diffuse high-energy neutrinos produced in the Milky Way by the interaction of cosmic rays with the interstellar medium. These comparative signals should be observable by large neutrino detectors.  相似文献   

Halo assembly bias in the quasi-linear regime     

Jose Ariel Keselman  Adi Nusser 《Monthly notices of the Royal Astronomical Society》2007,382(4):1853-1858

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Climate projections over different climatic regions of Afghanistan under shared socioeconomic scenarios     

Sediqi  Mohammad Naser  Hendrawan  Vempi Satriya Adi  Komori  Daisuke 《Theoretical and Applied Climatology》2022,149(1-2):511-524

Theoretical and Applied Climatology - The global climate models (GCMs) of Coupled Model Intercomparison Project phase 6 (CMIP6) were used for spatiotemporal projections of precipitation and...  相似文献   

Die Eisverhältnisse des Winters 1949/50 an den deutschen Küsten zwischen Ems und Oder     

Franz Nusser 《Ocean Dynamics》1950,3(5-6):335-341

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Gebiete gleicher Eisvorbereitungszeit an den deutschen Küsten     

Franz Nusser 《Ocean Dynamics》1950,3(3-4):220-227

Zusammenfassung Aus dem praktischen Eisdienst entstand die Frage, wieviele zusammenhängende Tage mit negativem Mittel der Lufttemperatur nötig sind, bis sich in den verschiedenen Gebieten der deutschen Küsten das erste Eis bildet. Diese Zeit, in vorliegender Arbeit Eisvorbereitungszeit genannt, wurde aus einer 28jährigen Beobachtungsreihe ermittelt. Es zeigte sich, da die Eisvorbereitungszeit, im einzelnen modifiziert durch hydrographische und klimatologische Einflüsse, vor allem von der Morphologie der Küstengebiete abhängt. Die Nordseeküste mit ihren vorgelagerten Watten und Flachwassergebieten braucht eine kürzere Eisvorbereitungszeit als die rascher abfallende Ostseeküste. Dieser Unterschied wird besonders deutlich, wenn man die Schles wig-Holsteinische Küste der Ostsee zum Vergleich heranzieht.

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Regions of equal duration of ice-generation on the German coasts

Summary The following problem arose from the practical ice service: How many consecutive days with a negative mean temperature are required for the generation of the first ice in the different regions of the German coastal waters ? This span of time which in the present paper is called the Eisvorbereitungszeit (duration of ice generation) was calculated from a period of 28 years. Its length was found to depend chiefly on the morphology of the coastal regions, with modifications due to the special hydrographical and climatological features. In the German Bight of the North Sea the duration of ice generation is shorter than in the Baltic owing to the shallow water, especially the Watt, i. e. the banks which dry at low water, whereas the shores of the Baltic are in comparison steeper. This difference becomes particularly evident by comparing the west and east coasts of Schleswig-Holstein.

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Die Entdeckung der Nordwestpassage vor 100 Jahren und die erste Bezwingung der Nordostpassage vor fast 75 Jahren — zwei Jubiläen     

Franz Nusser 《Ocean Dynamics》1953,6(4-6):227-230

Ohne Zusammenfassung  相似文献