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Articles 421 - 450 of 476
Full-Text Articles in Astrophysics and Astronomy
The Effects Of Gasdynamics, Cooling, Star Formation, And Numerical Resolution In Simulations Of Cluster Formation, Gf Lewis, A Babul, N Katz, T Quinn, L Hernquist, Dh Weinberg
The Effects Of Gasdynamics, Cooling, Star Formation, And Numerical Resolution In Simulations Of Cluster Formation, Gf Lewis, A Babul, N Katz, T Quinn, L Hernquist, Dh Weinberg
Astronomy Department Faculty Publication Series
We present the analysis of a suite of simulations of a Virgo-mass galaxy cluster. Undertaken within the framework of standard cold dark matter cosmology, these simulations were performed at differing resolutions and with increasingly complex physical processes, with the goal of identifying the effects of each on the evolution of the cluster. We focus on the cluster at the present epoch and examine properties including the radial distributions of density, temperature, entropy, and velocity. We also map "observable" projected properties such as the surface mass density, X-ray surface brightness, and Sunyaev-Zeldovich signature. We identify significant differences between the simulations, which …
Title: Recent X-Ray Observations Of Disk Galaxies: Tracing The Dynamic Interstellar Medium, Qd Wang
Title: Recent X-Ray Observations Of Disk Galaxies: Tracing The Dynamic Interstellar Medium, Qd Wang
Astronomy Department Faculty Publication Series
I review recent results from our deep ROSAT and Chandra observations of two galaxies, M101 and NGC 4631, in fields of exceptionally low Galactic extinction. Large amounts of X-ray-emitting gas are detected in these galaxies. Such gas is produced primarily in massive star forming regions and have an average characteristic temperature of a few times $10^6$ K. Cooler gas ($\sim 10^6$ K) is found typically outside galactic disks and may represent outflows from blown-out superbubbles. Propagation of star formation, driven by the expansion of hot gas, appears to be operating in giant HII complexes. A substantial fraction of photo-evaporated gas …
Perturbations Of Spherical Stellar Systems During Fly-By Encounters, E. Vesperini, Martin D. Weinberg
Perturbations Of Spherical Stellar Systems During Fly-By Encounters, E. Vesperini, Martin D. Weinberg
Astronomy Department Faculty Publication Series
We study the internal response of a galaxy to an unbound encounter and present a survey of orbital parameters covering typical encounters in different galactic environments. Overall, we conclude that relatively weak encounters by low-mass interloping galaxies can cause observable distortions in the primaries. The resulting asymmetries may persist long after the interloper is evident. We focus our attention on the production of structure in dark halos and in cluster ellipticals. Any distortion produced in a dark halo can distort the embedded stellar disk, possibly leading to the formation of lopsided and warped disks. We show that distant encounters with …
An Adaptive Algorithm For N-Body Field Expansions, Md Weinberg
An Adaptive Algorithm For N-Body Field Expansions, Md Weinberg
Astronomy Department Faculty Publication Series
An expansion of a density field or particle distribution in basis functions that solve the Poisson equation both provides an easily parallelized N-body force algorithm and simplifies perturbation theories. The expansion converges quickly and provides the highest computational advantage if the lowest order potential-density pair in the basis looks like the unperturbed galaxy or stellar system. Unfortunately, there are only a handful of such bases in the literature that limit this advantage. This paper presents an algorithm for deriving these bases to match a wide variety of galaxy models. The method is based on efficient numerical solution of the Sturm-Liouville …
Closing In On Omega(M): The Amplitude Of Mass Fluctuations From Galaxy Clusters And The Ly Alpha Forest, Dh Weinberg, Rac Croft, L Hernquist, N Katz, M Pettini
Closing In On Omega(M): The Amplitude Of Mass Fluctuations From Galaxy Clusters And The Ly Alpha Forest, Dh Weinberg, Rac Croft, L Hernquist, N Katz, M Pettini
Astronomy Department Faculty Publication Series
We estimate the present-day value of the matter density parameter ΩM by combining constraints from the galaxy cluster mass function with Croft et al.'s recent measurement of the mass power spectrum, P(k), from Lyα forest data. The key assumption of the method is that cosmic structure formed by gravitational instability from Gaussian primordial fluctuations. For a specified value of ΩM, matching the observed cluster mass function then fixes the value of σ8, the rms amplitude of mass fluctuations in 8 h-1 Mpc spheres, and it thus determines the normalization of P …
Properties Of Galaxy Clusters: Mass And Correlation Functions, F Governato, A Babul, T Quinn, P Tozzi, Cm Baugh, N Katz, G Lake
Properties Of Galaxy Clusters: Mass And Correlation Functions, F Governato, A Babul, T Quinn, P Tozzi, Cm Baugh, N Katz, G Lake
Astronomy Department Faculty Publication Series
We analyse parallel N-body simulations of three cold dark matter (CDM) universes to study the abundance and clustering of galaxy clusters. The simulation boxes are 500 h−1 Mpc on a side and cover a volume comparable to that of the forthcoming Sloan Digital Sky Survey. The use of a treecode algorithm and 47 million particles allows us at the same time to achieve high mass and force resolution. We are thus able to make robust measurements of cluster properties with good number statistics up to a redshift larger than unity. We extract haloes using two independent, public domain …
The Clustering Of High-Redshift Galaxies In The Cold Dark Matter Scenario, N Katz, L Hernquist, Dh Weinberg
The Clustering Of High-Redshift Galaxies In The Cold Dark Matter Scenario, N Katz, L Hernquist, Dh Weinberg
Astronomy Department Faculty Publication Series
We investigate the clustering of high-redshift galaxies in five variants of the cold dark matter (CDM) scenario, using hydrodynamic cosmological simulations that resolve the formation of systems with circular velocities vc ≥ 100 km s-1 (Ω = 1) or vc ≥ 70 km s-1 (Ω = 0.4). Although the five models differ in their cosmological parameters and in the shapes and amplitudes of their mass power spectra, they predict remarkably similar galaxy clustering at z = 2, 3, and 4. The galaxy correlation functions show almost no evolution over this redshift range, even though the mass …
The Power Spectrum Of Mass Fluctuations Measured From The Ly Alpha Forest At Redshift Z=2.5, Rac Croft, Dh Weinberg, M Pettini, L Hernquist, N Katz
The Power Spectrum Of Mass Fluctuations Measured From The Ly Alpha Forest At Redshift Z=2.5, Rac Croft, Dh Weinberg, M Pettini, L Hernquist, N Katz
Astronomy Department Faculty Publication Series
We measure the linear power spectrum of mass-density fluctuations at redshift z = 2.5 from the Lyα forest absorption in a sample of 19 QSO spectra, using the method introduced by Croft et al. The P(k) measurement covers the range 2π/k ~ 450-2350 km s-1 (2-12 comoving h-1 Mpc for Ω = 1), limited on the upper end by uncertainty in fitting the unabsorbed QSO continuum and on the lower end by finite spectral resolution (0.8-2.3 Å FWHM) and by nonlinear dynamical effects. We examine a number of possible sources of systematic error and …
The Nature Of Lyman Break Galaxies In Cosmological Hydrodynamic Simulations, R Dave, J Gardner, L Hernquist, N Katz, D Weinberg
The Nature Of Lyman Break Galaxies In Cosmological Hydrodynamic Simulations, R Dave, J Gardner, L Hernquist, N Katz, D Weinberg
Astronomy Department Faculty Publication Series
What type of objects are being detected as $z\sim 3$ "Lyman break galaxies"? Are they predominantly the most massive galaxies at that epoch, or are many of them smaller galaxies undergoing a short-lived burst of merger-induced star formation? We attempt to address this question using high-resolution cosmological hydrodynamic simulations including star formation and feedback. Our $\Lambda$CDM simulation, together with Bruzual-Charlot population synthesis models, reproduces the observed number density and luminosity function of Lyman break galaxies when dust is incorporated. The inclusion of dust is crucial for this agreement. In our simulation, these galaxies are predominantly the most massive objects at …
The Low-Redshift Ly Alpha Forest In Cold Dark Matter Cosmologies, R Dave, L Hernquist, N Katz, Dh Weinberg
The Low-Redshift Ly Alpha Forest In Cold Dark Matter Cosmologies, R Dave, L Hernquist, N Katz, Dh Weinberg
Astronomy Department Faculty Publication Series
We study the physical origin of the low-redshift Lyα forest in hydrodynamic simulations of four cosmological models, all variants of the cold dark matter scenario. Our most important conclusions are insensitive to the cosmological model, but they depend on our assumption that the UV background declines at low redshift in concert with the declining population of quasar sources. We find that the expansion of the universe drives rapid evolution of dN/dz (the number of absorbers per unit redshift above a specified equivalent width threshold) at z1.7, but that at lower redshift the fading of the UV background …
Evolution Of Clustering And Bias In A Lambda-Cdm Universe, R Dave, L Hernquist, N Katz, Dh Weinberg
Evolution Of Clustering And Bias In A Lambda-Cdm Universe, R Dave, L Hernquist, N Katz, Dh Weinberg
Astronomy Department Faculty Publication Series
We determine the evolution from $z=3\to 0$ of the galaxy and mass correlation functions and bias factor in a $50h^{-1}$Mpc $\Lambda$CDM hydrodynamic simulation with $10h^{-1}$kpc resolution. The mass correlation function grows with time, but the galaxy correlation function shows little evolution and is well described by a power law. At early times, galaxies are biased traces of mass, with bias being higher on smaller scales. By z=0, galaxies trace the mass, and the bias shows little scale dependence.
Effect Of The Magellanic Clouds On The Milky Way Disk And Vice Versa, Martin D. Weinberg
Effect Of The Magellanic Clouds On The Milky Way Disk And Vice Versa, Martin D. Weinberg
Astronomy Department Faculty Publication Series
We introduce a new galaxy image decomposition tool, GALPHAT (GALaxy PHotometric ATtributes), to provide full posterior probability distributions and reliable confidence intervals for all model parameters. GALPHAT is designed to yield a high speed and accurate likelihood computation, using grid interpolation and Fourier rotation. We benchmark this approach using an ensemble of simulated Sersic model galaxies over a wide range of observational conditions: the signal-to-noise ratio S/N, the ratio of galaxy size to the PSF and the image size, and errors in the assumed PSF; and a range of structural parameters: the half-light radius $r_e$ and the Sersic index $n$. …
Discovery Of Four Field Methane (T-Type) Dwarfs With The Two Micron All-Sky Survey, Adam J. Burgasser, J. Davy Kirkpatrick, Michael E. Brown, I. Neill Reid, John E. Gizis, Conard C. Dahn, David G. Monet, Charles A. Beichman, James Liebert, Roc M. Cutri, Michael F. Skrutskie
Discovery Of Four Field Methane (T-Type) Dwarfs With The Two Micron All-Sky Survey, Adam J. Burgasser, J. Davy Kirkpatrick, Michael E. Brown, I. Neill Reid, John E. Gizis, Conard C. Dahn, David G. Monet, Charles A. Beichman, James Liebert, Roc M. Cutri, Michael F. Skrutskie
Astronomy Department Faculty Publication Series
We report the discovery of four field methane ("T"-type) brown dwarfs using Two Micron All-Sky Survey (2MASS) data. One additional methane dwarf, previously discovered by the Sloan Digital Sky Survey, was also identified. Near-infrared spectra clearly show the 1.6 and 2.2 m CH4 absorption bands characteristic of objects with Teff 1300 K as well as broadened H2O bands at 1.4 and 1.9 m. Comparing the spectra of these objects with that of Gl 229B, we propose that all new 2MASS T dwarfs are warmer than 950 K, in order from warmest to coolest: 2MASS J1217-03, 2MASS J1225-27, 2MASS J1047+21, and …
L Dwarfs And The Substellar Mass Function, I. Neill Reid, J. Davy Kirkpatrick, J. Liebert, A. Burrows, J. E. Gizis, A. Burgasser, C. C. Dahn, D. Monet, R. Cutri, C. A. Beichman, M. Skrutskie
L Dwarfs And The Substellar Mass Function, I. Neill Reid, J. Davy Kirkpatrick, J. Liebert, A. Burrows, J. E. Gizis, A. Burgasser, C. C. Dahn, D. Monet, R. Cutri, C. A. Beichman, M. Skrutskie
Astronomy Department Faculty Publication Series
Analysis of initial observations sky surveys has shown that the resulting photometric catalogs, combined with far-red optical data, provide an extremely effective method of finding isolated, very low-temperature objects in the general field. Follow-up observations have already identified more than 25 sources with temperatures cooler than the latest M dwarfs. A comparison with detailed model predictions (Burrows & Sharp 1999) indicates that these L dwarfs have effective temperatures between 2000 ± 100 K and 1500 ± 100 K, while the available trigonometric parallax data place their luminosities at between 10-3.5 and 10. Those properties, together with the detection of lithium …
Effect Of The Magellanic Clouds On The Milky Way Disk And Vice Versa, Martin D. Weinberg
Effect Of The Magellanic Clouds On The Milky Way Disk And Vice Versa, Martin D. Weinberg
Astronomy Department Faculty Publication Series
The satellite-disk interaction provides limits on halo properties in two ways: (1) physical arguments motivate the excitation of observable Galactic disk structure in the presence of a massive halo, although precise limits on halo parameters are scenario-dependent; (2) conversely, the Milky Way as a whole has significant dynamical effect on LMC structure and this interaction also leads to halo limits. Together, these scenarios give strong corroboration of our current gravitational mass estimates and suggests a rapidly evolving LMC.
Fluctuations In Finite-N Equilibrium Stellar Systems, Md Weinberg
Fluctuations In Finite-N Equilibrium Stellar Systems, Md Weinberg
Astronomy Department Faculty Publication Series
Gravitational amplification of Poisson noise in stellar systems is important on large scales. For example, it increases the dipole noise power by roughly a factor of 6 and the quadrupole noise by 50 per cent for a King model profile. The dipole noise is amplified by a factor of 15 for the core-free Hernquist model. The predictions are computed by summing over the wakes caused by each star in the system — the dressed-particle formalism of Rostoker & Rosenbluth — and are demonstrated by N-body simulation. This result implies that a collisionless N-body simulation is impossible; the fluctuation noise which …
Dynamics Of An Interacting Luminous Disc, Dark Halo And Satellite Companion, Md Weinberg
Dynamics Of An Interacting Luminous Disc, Dark Halo And Satellite Companion, Md Weinberg
Astronomy Department Faculty Publication Series
This paper describes a method, based on linear perturbation theory, to determine the dynamical interaction between extended halo and spheroid components and an environmental disturbance. One finds that resonant interaction between a galaxy and passing interlopers or satellite companions can carry the disturbance inward, deep inside the halo, where it can perturb the disc. Applied to the Milky Way for example, the LMC and SMC appear to be sufficient to cause the observed Galactic warp and possibly seed other asymmetries. This is a multi-scale interaction in which the halo wake has a feature at roughly half the satellite orbital radius …
New Insight On Galaxy Structure From Galphat I. Motivation, Methodology, And Benchmarks For Sersic Models, Ilsang Yoon, Martin D. Weinberg
New Insight On Galaxy Structure From Galphat I. Motivation, Methodology, And Benchmarks For Sersic Models, Ilsang Yoon, Martin D. Weinberg
Astronomy Department Faculty Publication Series
We introduce a new galaxy image decomposition tool, GALPHAT (GALaxy PHotometric ATtributes), to provide full posterior probability distributions and reliable confidence intervals for all model parameters. GALPHAT is designed to yield a high speed and accurate likelihood computation, using grid interpolation and Fourier rotation. We benchmark this approach using an ensemble of simulated Sersic model galaxies over a wide range of observational conditions: the signal-to-noise ratio S/N, the ratio of galaxy size to the PSF and the image size, and errors in the assumed PSF; and a range of structural parameters: the half-light radius $r_e$ and the Sersic index $n$. …
Morphological Transformation From Galaxy Harassment, B Moore, G Lake, N Katz
Morphological Transformation From Galaxy Harassment, B Moore, G Lake, N Katz
Astronomy Department Faculty Publication Series
Galaxy morphologies in clusters have undergone a remarkable transition over the past several billion yr. Distant clusters at z ~ 0.4 are filled with small spiral galaxies, many of which are disturbed and show evidence of multiple bursts of star formation. This population is absent from nearby clusters, where spheroidals comprise the faint end of the luminosity function. Our numerical simulations follow the evolution of disk galaxies in a rich cluster resulting from encounters with brighter galaxies and the cluster's tidal field, or "galaxy harassment." After a bursting transient phase, they undergo a complete morphological transformation from "disks" to "spheroidals." …
Recovery Of The Power Spectrum Of Mass Fluctuations From Observations Of The Ly Alpha Forest, Rac Croft, Dh Weinberg, N Katz, L Hernquist
Recovery Of The Power Spectrum Of Mass Fluctuations From Observations Of The Ly Alpha Forest, Rac Croft, Dh Weinberg, N Katz, L Hernquist
Astronomy Department Faculty Publication Series
We present a method to recover the shape and amplitude of the power spectrum of mass fluctuations, P(k), from observations of the high-redshift Lyα forest. The method is motivated by the physical picture that has emerged from hydrodynamic cosmological simulations and related semianalytic models, in which typical Lyα forest lines arise in a diffuse, continuous, fluctuating intergalactic medium. The thermal state of this low-density gas (δρ/ρ 10) is governed by simple physical processes, which lead to a tight correlation between the Lyα optical depth and the underlying matter density. To recover the mass power spectrum, we (1) …
Origin And Evolution Of The Cepheus Bubble, Na Patel, Pf Goldsmith, Mh Heyer, Rl Snell, P Pratap
Origin And Evolution Of The Cepheus Bubble, Na Patel, Pf Goldsmith, Mh Heyer, Rl Snell, P Pratap
Astronomy Department Faculty Publication Series
We have imaged a 10° × 10° region of the Cepheus bubble in the J = 1-0 line of CO and the 21 cm line of atomic hydrogen. The CO emission defines a giant expanding shell 120 pc in diameter, which is similar to that seen in the IRAS sky maps. We estimate the total gas mass in the region to be ~4 × 105M☉. The total kinetic energy from the observed spread of velocities of the molecular clouds is ~1051ergs. We suggest that the members of earlier generations of massive stars in NGC 7160 are responsible for …
Constraining The Metallicity Of The Low-Density Ly Alpha Forest Using O Vi Absorption, R Dave, U Hellsten, L Hernquist, N Katz, Dh Weinberg
Constraining The Metallicity Of The Low-Density Ly Alpha Forest Using O Vi Absorption, R Dave, U Hellsten, L Hernquist, N Katz, Dh Weinberg
Astronomy Department Faculty Publication Series
We present a systematic search for O VI (1032, 1037 Å) absorption in a Keck High-Resolution Echelle Spectrometer spectrum of the z = 3.62 quasar Q1422+231, with the goal of constraining the metallicity and ionization state of the low-density intergalactic medium (IGM). Comparison of C IV absorption measurements to models of the Lyα forest based on cosmological simulations shows that absorbers with NH I 1014.5 cm-2 have a mean carbon abundance [C/H] -2.5, assuming a metagalactic photoionizing background with the spectral shape predicted by Haardt and Madau in 1996. In these models, lower column density absorption arises …
The Observability Of Metal Lines Associated With The Ly Alpha Forest, U Hellsten, L Hernquist, N Katz, Dh Weinberg
The Observability Of Metal Lines Associated With The Ly Alpha Forest, U Hellsten, L Hernquist, N Katz, Dh Weinberg
Astronomy Department Faculty Publication Series
We develop a prescription for characterizing the strengths of metal lines associated with Lyα forest absorbers (LYFAs) of a given neutral hydrogen column density NH I and metallicity [O/H]. This line observability index (LOX) is line specific and translates, for weak lines, into a measure of the equivalent width. It can be evaluated quickly for thousands of transitions within the framework of a given model of the Lyα forest, providing a ranking of the absorption lines in terms of their strengths and enabling model builders to select the lines that deserve more detailed consideration, i.e., those that should be …
Cosmological Simulations With Scale-Free Initial Conditions. I. Adiabatic Hydrodynamics, Jm Owen, Dh Weinberg, Ae Evrard, L Hernquist, N Katz
Cosmological Simulations With Scale-Free Initial Conditions. I. Adiabatic Hydrodynamics, Jm Owen, Dh Weinberg, Ae Evrard, L Hernquist, N Katz
Astronomy Department Faculty Publication Series
We analyze hierarchical structure formation based on scale-free initial conditions in an Einstein-de Sitter universe, including a baryonic component with Ωbary = 0.05. We present three independent, smoothed particle hydrodynamics (SPH) simulations, performed at two resolutions (323 and 643 dark matter and baryonic particles) and with two different SPH codes (TreeSPH and P3MSPH). Each simulation is based on identical initial conditions, which consist of Gaussian-distributed initial density fluctuations that have a power spectrum P(k) k-1. The baryonic material is modeled as an ideal gas subject only to shock heating and adiabatic heating …
The Formation Of Quasars In Low-Luminosity Hosts Via Galaxy Harassment, G Lake, N Katz, B Moore
The Formation Of Quasars In Low-Luminosity Hosts Via Galaxy Harassment, G Lake, N Katz, B Moore
Astronomy Department Faculty Publication Series
We have simulated disk galaxies undergoing continual bombardment by other galaxies in a rich cluster. "Galaxy harassment" leads to dramatic evolution of smaller disk galaxies and provides an extremely effective mechanism for fueling a central quasar. Within a few billion years after a small disk galaxy enters the cluster environment, up to 90% of its gas can be driven into the inner 500 pc. Up to half of the mass can be transferred in a burst lasting just 100-200 Myr. This transport of gas to the center of galaxy is far more efficient than any mechanism proposed before. Galaxy harassment …
Cosmology With The Lyman-Alpha Forest, Dh Weinberg, S Burles, Rac Croft, R Dave, G Gomez, L Hernquist, N Katz, D Kirkman, S Liu, J Miralda-Escude, M Penttini, J Phillips, D Tytler, J Wright
Cosmology With The Lyman-Alpha Forest, Dh Weinberg, S Burles, Rac Croft, R Dave, G Gomez, L Hernquist, N Katz, D Kirkman, S Liu, J Miralda-Escude, M Penttini, J Phillips, D Tytler, J Wright
Astronomy Department Faculty Publication Series
We outline the physical picture of the high-redshift Ly-alpha forest that has emerged from cosmological simulations, describe statistical characteristics of the forest that can be used to test theories of structure formation, present a preliminary comparison between simulation results and measurements from Keck HIRES spectra, and discuss a recent determination of the slope and amplitude of the linear mass power spectrum P(k) at z=2.5 from moderate resolution spectra. The physical picture is simple if each QSO spectrum is viewed as a continuous non-linear map of the line-of-sight density field rather than a collection of discrete absorption lines. The distribution of …
Cosmology From The Structure Of The Lyman-Alpha Forest, R Croft, D Weinberg, N Katz, L Hernquist
Cosmology From The Structure Of The Lyman-Alpha Forest, R Croft, D Weinberg, N Katz, L Hernquist
Astronomy Department Faculty Publication Series
A convincing physical picture for the Lyman-alpha forest has emerged from simulations and related semi-analytic studies of structure formation models. Observations can be be used in the context of this picture to study cosmology using the structure of the forest. With the availability of well motivated predictions, not only has it become possible to test models directly, but the physical processes involved appear to be simple enough that we can attempt to reconstruct aspects of the underlying cosmology from observations. We briefly summarise the method of Croft et al (1997) (astro-ph/9708018) for recovering the primordial mass power spectrum …
Simulating Gas At High Redshift, N Katz, L Hernquist, Dh Weinberg
Simulating Gas At High Redshift, N Katz, L Hernquist, Dh Weinberg
Astronomy Department Faculty Publication Series
We discuss simulations of gas at high redshift. We briefly review the methods used and the results for quasar absorption lines. We present gas mass functions and galaxy correlation functions for 5 different cosmological models. Galaxies should be detectable at redshifts greater than 2 by SKAI, and measurements of the gas maWe discuss simulations of gas at high redshift. We briefly review the methods used and the results for quasar absorption lines. We present gas mass functions and galaxy correlation functions for 5 different cosmological models. Galaxies should be detectable at redshifts greater than 2 by SKAI, and measurements of …
Fluctuations In Finite N Equilibrium Stellar Systems, Martin D. Weinberg
Fluctuations In Finite N Equilibrium Stellar Systems, Martin D. Weinberg
Astronomy Department Faculty Publication Series
Gravitational amplification of Poisson noise in stellar systems is important on large scales. For example, it increases the dipole noise power by roughly a factor of six and the quadrupole noise by 50% for a King model profile. The dipole noise is amplified by a factor of fifteen for the core-free Hernquist model. The predictions are computed using the dressed-particle formalism of Rostoker & Rosenbluth (1960) and are demonstrated by n-body simulation. This result implies that a collisionless n-body simulation is impossible; The fluctuation noise which causes relaxation is an intrinic part of self gravity. In other words, eliminating two-body …
Dynamics Of An Interacting Luminous Disk, Dark Halo, And Satellite Companion, Martin D. Weinberg
Dynamics Of An Interacting Luminous Disk, Dark Halo, And Satellite Companion, Martin D. Weinberg
Astronomy Department Faculty Publication Series
This paper describes a method for determining the dynamical interaction between extended halo and spheroid components and an environmental disturbance. One finds that resonant interaction between a galaxy and passing interlopers or satellite companions can carry the disturbance inward, deep inside the halo, where it can perturb the disk. Applied to the Milky Way for example, the LMC and SMC appear to be sufficient to cause the observed Galactic warp and possibly seed other asymmetries. This is a multi-scale interaction in which the halo wake has a feature at roughly half the satellite orbital radius due to a 2:1 orbital …