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1998

Astrophysics and Astronomy

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Articles 1 - 30 of 105

Full-Text Articles in Physical Sciences and Mathematics

Gravitational Waves From Collapsing Vacuum Domains, Marcelo Gleiser, Ronald Roberts Dec 1998

Gravitational Waves From Collapsing Vacuum Domains, Marcelo Gleiser, Ronald Roberts

Dartmouth Scholarship

The breaking of an approximate discrete symmetry, the final stages of a first order phase transition, or a postinflationary biased probability distribution for scalar fields are possible cosmological scenarios characterized by the presence of unstable domain wall networks. Combining analytical and numerical techniques, we show that the nonspherical collapse of these domains can be a powerful source of gravitational waves. We compute their contribution to the stochastic background of gravitational radiation and explore their observability by present and future gravitational wave detectors.

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The Motions Of Clusters Of Galaxies And The Dipoles Of The Peculiar Velocity Field, Riccardo Giovanelli, Martha P. Haynes, John J. Salzer, Gary Wegner Dec 1998

The Motions Of Clusters Of Galaxies And The Dipoles Of The Peculiar Velocity Field, Riccardo Giovanelli, Martha P. Haynes, John J. Salzer, Gary Wegner

Dartmouth Scholarship

In preceding papers of this series, TF relations for galaxies in 24 clusters with radial velocities between 1000 and 9200 km s-1 (SCI sample) were obtained, a Tully-Fisher (TF) template relation was constructed, and mean offsets of each cluster with respect to the template were obtained. Here, an estimate of the line-of-sight peculiar velocities of the clusters and their associated errors are given. It is found that cluster peculiar velocities in the cosmic microwave background reference frame do not exceed 600 km s-1 and that their distribution has a line-of-sight dispersion of 300 km s-1, suggesting …

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Cluster Versus Field Elliptical Galaxies And Clues On Their Formation, Mariangela Bernardi, Alvio Renzini, Luiz N. Da Costa, Gary Wegner Dec 1998

Cluster Versus Field Elliptical Galaxies And Clues On Their Formation, Mariangela Bernardi, Alvio Renzini, Luiz N. Da Costa, Gary Wegner

Dartmouth Scholarship

Using new observations for a sample of 931 early-type galaxies, we investigate whether the Mg2-σ0 relation shows any dependence on the local environment. The galaxies have been assigned to three different environments depending on the local overdensity (clusters, groups, and field); we used our complete redshift database to guide the assignment of galaxies. It is found that cluster, group, and field early-type galaxies follow almost identical Mg2-σ0 relations, with the largest Mg2 zero-point difference (clusters minus field) being only 0.007±0.002 mag. No correlation of the residuals is found with the morphological type or …

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Strong Dissipative Behavior In Quantum Field Theory, Arjun Berera, Marcelo Gleiser, Rudnei O. Ramos Nov 1998

Strong Dissipative Behavior In Quantum Field Theory, Arjun Berera, Marcelo Gleiser, Rudnei O. Ramos

Dartmouth Scholarship

We study the conditions under which an overdamped regime can be attained in the dynamic evolution of a quantum field configuration. Using a real-time formulation of finite temperature field theory, we compute the effective evolution equation of a scalar field configuration, quadratically interacting with a given set of other scalar fields. We then show that, in the overdamped regime, the dissipative kernel in the field equation of motion is closely related to the shear viscosity coefficient, as computed in scalar field theory at finite temperature. The effective dynamics is equivalent to a time-dependent Ginzburg-Landau description of the approach to equilibrium …

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Near–Infrared Classification Spectroscopy: H–Band Spectra Of Fundamental Mk Standards, Michael R. Meyer, Suzan Edwards, Kenneth H. Hinkle, Stephen E. Strom Nov 1998

Near–Infrared Classification Spectroscopy: H–Band Spectra Of Fundamental Mk Standards, Michael R. Meyer, Suzan Edwards, Kenneth H. Hinkle, Stephen E. Strom

Astronomy: Faculty Publications

We present a catalog of H-band spectra for 85 stars of approximately solar abundance observed at a resolving power of 3000 with the KPNO Mayall 4 m Fourier Transform Spectrometer. The atlas covers spectral types O7M5 and luminosity classes IV as defined in the MK system. We identify both atomic and molecular indices and line ratios that are temperature and luminosity sensitive, allowing spectral classification to be carried out in the H-band. The line ratios permit spectral classification in the presence of continuum excess emission, which is commonly found in premain-sequence or evolved stars. We demonstrate that with …

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Effect Of The Magellanic Clouds On The Milky Way Disk And Vice Versa, Martin D. Weinberg Nov 1998

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.

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Co (J = 4 → 3) And 650 Micron Continuum Observations Of The Z = 0.93 Hyperluminous Infrared Galaxy Fsc 15307+3252, Min S. Yun, N Z. Scoville Nov 1998

Co (J = 4 → 3) And 650 Micron Continuum Observations Of The Z = 0.93 Hyperluminous Infrared Galaxy Fsc 15307+3252, Min S. Yun, N Z. Scoville

Min S. Yun

We report the results of our CO J = 4 → 3 line and rest-frame 650 μm continuum observations of the z = 0.93 hyperluminous infrared galaxy FSC 15307+3252 using the Owens Valley Millimeter Array. No line or continuum emission was detected, but the derived limits provide a useful constraint on the temperature, emissivity, and mass of the cold dust associated with FSC 15307+3252 and its molecular gas content. The 3 σ upper limit on the velocity-integrated CO (4-3) line flux is 1.6 Jy km s-1 (for ΔV = 300 km s-1). This corresponds to a surprisingly small total molecular …

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Flows On Scales Of 150 Mpc?, K. R. Müller, W. Freudling, R. Watkins, G. Wegner Nov 1998

Flows On Scales Of 150 Mpc?, K. R. Müller, W. Freudling, R. Watkins, G. Wegner

Dartmouth Scholarship

In order to investigate the reality of large-scale streaming motion on scales of up to 150 Mpc, we have studied the peculiar motions of ~200 early-type galaxies in three directions of the South Equatorial Strip at distances out to ~20,000 km s-1. The new Automatic Plate Measuring Facility South Equatorial Strip Catalog (-175<δ<+25) was used to select the sample of field galaxies in three directions: (1) 15h10m-16h10m; (2) 20h30m-21h50m; (3) 00h10m-01h30m. New R-band CCD photometry and spectroscopic data for the galaxies are used. The fundamental plane distance-indicator …

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Quasars As Cosmological Probes: The Ionizing Continuum, Gas Metallicity, And The WΛ-L Relation, Kirk Korista, Jack Baldwin, Gary J. Ferland Nov 1998

Quasars As Cosmological Probes: The Ionizing Continuum, Gas Metallicity, And The WΛ-L Relation, Kirk Korista, Jack Baldwin, Gary J. Ferland

Physics and Astronomy Faculty Publications

Using a realistic model for line emission from the broad emission line regions of quasars, we are able to reproduce the previously observed correlations of emission-line ratios with the shape of the spectral energy distribution (SED). In agreement with previous studies, we find that the primary driving force behind the Baldwin effect (Wλ ~ Lβ, β < 0) is a global change in the SED with quasar luminosity, in that more luminous quasars must have characteristically softer ionizing continua. This is completely consistent with observations that show (1) a correlation between Luv, αox, and αuvx (2) correlations of SED shape-sensitive line ratios with αox, αuvx, and Luv; and (3) correlations between line equivalent widths and αox, αuvx …

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A Photometric And Kinematic Study Of Awm 7, Daniel M. Koranyi, Margaret Geller, Joseph J. Mohr, Gary Wegner Nov 1998

A Photometric And Kinematic Study Of Awm 7, Daniel M. Koranyi, Margaret Geller, Joseph J. Mohr, Gary Wegner

Dartmouth Scholarship

We have measured redshifts and Kron-Cousins R-band magnitudes for a sample of galaxies in the poor cluster AWM 7. We have measured redshifts for 172 galaxies; 106 of these are cluster members. We determine the luminosity function (LF) from a photometric survey of the central 1.2 × 1.2 h-1 Mpc. The LF has a bump at the bright end and a faint-end slope of α = -1.37 ± 0.16, populated almost exclusively by absorption-line galaxies. The cluster velocity dispersion is lower in the core (~530 km s-1) than at the outskirts (~680 km s-1), …

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A Search For Lithium-Rich Giants Among Stars With Infrared Excesses, Francis C. Fekel, Lyndon C. Watson Nov 1998

A Search For Lithium-Rich Giants Among Stars With Infrared Excesses, Francis C. Fekel, Lyndon C. Watson

Information Systems and Engineering Management Research Publications

The unusual nature of the single, rapidly rotating, lithium-rich K giant HDE 233517, which is currently undergoing significant mass loss, prompted a search for giants with similar properties. High-dispersion spectroscopic observations were obtained of HD 219025, a known lithium-rich infrared-excess giant, plus 39 stars from a list of G and K giants with excess far-infrared emission. The projected rotational velocities of the vast majority of infrared-excess giants appear to be similar to those of normal G and K giants. Six giants have lithium abundances at or above theoretical upper envelope values. The percentage of such stars in the sample of …

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Development Of A Hard X-Ray Polarimeter For Astrophysics, Mark L. Mcconnell, John R. Macri, M Mcclish, James M. Ryan, D J. Forrest, W T. Vestrand Nov 1998

Development Of A Hard X-Ray Polarimeter For Astrophysics, Mark L. Mcconnell, John R. Macri, M Mcclish, James M. Ryan, D J. Forrest, W T. Vestrand

Space Science Center

We have been developing a Compton scatter polarimeter for measuring the linear polarization of hard X-rays (100-300 keV) from astrophysical sources. A laboratory prototype polarimeter has been used to successfully demonstrate the reliability of our Monte Carlo simulation code and to demonstrate our ability to generate a polarized photon source in the lab. Our design concept places a self-containedpolarimeter module on the front-end of a a 5-inch position sensitive PMT (PSPMT). We are currently working on the fabrication of a science model based on this PSPMT concept. Although the emphasis of our development effort is towards measuring hard X-rays from …

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Temperature Fluctuations In Photoionized Nebulae. Ii. The Effect Of Inhomogeneous Abundances, J. B. Kingdon, Gary J. Ferland Oct 1998

Temperature Fluctuations In Photoionized Nebulae. Ii. The Effect Of Inhomogeneous Abundances, J. B. Kingdon, Gary J. Ferland

Physics and Astronomy Faculty Publications

Recent abundance determinations based on recombination lines in several emission-line nebulae yield ionic abundances several times larger than those derived from forbidden lines. These results cast uncertainty over all abundance determinations in such objects. One possible explanation for these discrepancies frequently cited in the literature is the presence of chemical inhomogeneities. We have run a series of photoionization models to examine what effect such inhomogeneities will have on the resulting temperature structure of nebulae. We then derive abundances from these models, utilizing Peimbert's t2 formalism. Our results suggest that, although chemical inhomogeneities may produce nonnegligible biases in abundance determinations …

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Molecular Gas In The Z = 2.8 Submillimeter Galaxy Smm 02399-0136, D T. Frayer, R J. Ivison, N Z. Scoville, Min S. Yun, A S. Evans, Ian Smail, A W. Blain, J P. Kneib Oct 1998

Molecular Gas In The Z = 2.8 Submillimeter Galaxy Smm 02399-0136, D T. Frayer, R J. Ivison, N Z. Scoville, Min S. Yun, A S. Evans, Ian Smail, A W. Blain, J P. Kneib

Min S. Yun

We report the detection of CO (3→2) emission from the submillimeter-selected hyperluminous galaxy SMM 02399-0136. This galaxy is the brightest source detected in the recent Submillimeter Common-User Bolometer Array surveys of the submillimeter sky. The optical counterpart of the submillimeter source has been identified as a narrow-line active galactic nucleus/starburst galaxy at z=2.8. The CO emission is unresolved, θlesssim5'', and is coincident in redshift and position with the optical counterpart. The molecular gas mass derived from the CO observations is 8×1010 h−275 M_{{\odot}}, after correcting for a lensing amplification factor of 2.5. The large CO luminosity suggests that a significant …

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Time Series Energy Production In Smoothed Particle Hydrodynamics Accretion Disks: Superhumps In The Am Canum Venaticorum Stars, James C. Simpson, Matt A. Wood Oct 1998

Time Series Energy Production In Smoothed Particle Hydrodynamics Accretion Disks: Superhumps In The Am Canum Venaticorum Stars, James C. Simpson, Matt A. Wood

Aerospace, Physics, and Space Science Faculty Publications

The energy production time series of our purely hydrodynamic accretion disk simulations display remarkable similarities with the observed light curves of dwarf novae superhumps in general and the AM CVn stars in particular. The superhump period excess as a function of mass ratio agrees well with earlier theoretical and numerical results, and the amplitudes and relative phases of the harmonics in the power spectra agree well with the observations. The morphology of the mean pulse profile appears to be a useful predictor of system mass ratio. Our modified smoothed particle hydrodynamics code time symmetrizes the interparticle forces when individual time …

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Cross Sections Fall 1998, Department Of Physics And Astronomy Oct 1998

Cross Sections Fall 1998, Department Of Physics And Astronomy

Cross Sections

No abstract provided.

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Hubble Space Telescope Images And Spectra Of The Remnant Of Sn 1885 In M31, Robert A. Fesen, Christopher L. Gerardy, Kevin M. Mclin, Andrew J. S. Hamilton Oct 1998

Hubble Space Telescope Images And Spectra Of The Remnant Of Sn 1885 In M31, Robert A. Fesen, Christopher L. Gerardy, Kevin M. Mclin, Andrew J. S. Hamilton

Dartmouth Scholarship

Near-UV Hubble Space Telescope images of the remnant of SN 1885 (S And) in M31 show a 070±005 diameter absorption disk silhouetted against M31's central bulge, at SN 1885's historically reported position. The disk's size corresponds to a linear diameter of 2.5±0.4 pc at a distance of 725±70 kpc, implying an average expansion velocity of 11,000±2000 km s-1 over 110 yr. Low-dispersion Faint Object Spectrograph spectra over 3200-4800 Å reveal that the absorption arises principally from Ca II H and K (equivalent width 215 Å), with weaker absorption features of Ca I 4227 Å and Fe I 3720 Å. The …

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Peculiar Velocity Dipoles Of Field Galaxies, Riccardo Giovanelli, Martha P. Haynes, Wolfram Freudling, Luiz N. Da Costa, John J. Salzer, Gary Wegner Oct 1998

Peculiar Velocity Dipoles Of Field Galaxies, Riccardo Giovanelli, Martha P. Haynes, Wolfram Freudling, Luiz N. Da Costa, John J. Salzer, Gary Wegner

Dartmouth Scholarship

The Tully-Fisher (TF) relation is applied to obtain peculiar velocities of field spiral galaxies and to calculate dipoles of the peculiar velocity field to cz8000 km s-1. The field galaxy sample is spatially coextensive with and completely independent of a cluster sample, for which dipole characteristics are given in a separate paper. Dipoles of the peculiar velocity field are obtained separately by applying (1) an inverse version of the TF relation and selecting galaxies by redshift windowing and (2) a direct TF relation, with velocities corrected for the inhomogeneous Malmquist bias and windowing galaxies by TF distance. …

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Wiyn Open Cluster Study. I. Deep Photometry Of Ngc188, Ted Von Hippel, Ata Sarajedini Oct 1998

Wiyn Open Cluster Study. I. Deep Photometry Of Ngc188, Ted Von Hippel, Ata Sarajedini

Publications

We have employed precise and carefully calibrated V - and I - band photometry of NGC 188 at WIYN Observatory to explore the cluster luminosity function (LF) and study the cluster white dwarfs. Our photometry is offset by V = 0.052 (fainter) from that of Sandage and Eggen & Sandage. All published photometry for the past three decades has been based on these two calibrations, which are in error by 0.05 ± 0.01. We employ the Pinsonneault et al. fiducial open cluster main sequence to derive a distance modulus of 11.43 ± 0.08 and E(B - V )=0.09, with …

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"Wcfields": A Magnetic Rotating Stellar Wind Model From Wind Compression Theory., R. Ignace, J. P. Cassinelli, J. E. Bjorkman Sep 1998

"Wcfields": A Magnetic Rotating Stellar Wind Model From Wind Compression Theory., R. Ignace, J. P. Cassinelli, J. E. Bjorkman

Richard Ignace

A stellar wind model for a magnetic rotating star is presented. We use the semianalytic wind compression model that predicts the two-dimensional geometry of outflows from rotating stars and consider the addition of a magnetic field. In the limit of weak magnetic fields, in such a way that the fields are unimportant in accelerating the flow, the wind compression model can be used to predict the magnetic field distribution throughout the wind, which is shown to follow the mass flux distribution. A compression of field lines near the equator results as the flow of material from higher latitudes brings magnetic …

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A Zero Point And Accidental Errors For Published Values Of [Fe/H] For Cool Giants, B. J. Taylor Sep 1998

A Zero Point And Accidental Errors For Published Values Of [Fe/H] For Cool Giants, B. J. Taylor

Faculty Publications

This paper is one of a series based on published values of [Fe/H] for late-type evolved stars. Only values of [Fe/H] from high-dispersion spectroscopy or related techniques are used. The narrative in this paper begins at a point where mean values of [Fe/H] have been derived for xiVir, alphaBoo, betaGem, and the Hyades giants. By using these stars as standard stars when necessary, a zero-point data base is assembled. This data base is then expanded into its final version by correcting and adding additional data in a step-by-step process. As that process proceeds, data comparisons are used to establish rms …

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An Analysis Of Temperature Dependent Photoluminescence Line Shapes In Ingan, John S. Colton, K. L. Teo, P. Y. Yu, E. R. Weber, M. F. Li, W. Lui, K. Uchida, H. Tokunaga, N. Akutsu, K. Matsumoto Sep 1998

An Analysis Of Temperature Dependent Photoluminescence Line Shapes In Ingan, John S. Colton, K. L. Teo, P. Y. Yu, E. R. Weber, M. F. Li, W. Lui, K. Uchida, H. Tokunaga, N. Akutsu, K. Matsumoto

Faculty Publications

Photoluminescence (PL) line shapes in InGaN multiple quantum well structures have been studied experimentally and theoretically between 10 and 300 K. The higher temperature PL spectra can be fitted qualitatively with a thermalized carrier distribution and a broadened joint-density-of-states. The low temperature PL line shapes suggest that carriers are not thermalized, as a result of localization by band-gap fluctuations. We deduce a localization energy of ~7 meV as compared with an activation energy of ~63 meV from thermal quenching of the PL intensity. We thus conclude that this activation energy and the band-gap fluctuation most likely have different origins.

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Near-Infrared Galaxy Counts To J And K ∼ 24 As A Function Of Image Size, Matthew A. Bershady, James D. Lowenthal, David C. Koo Sep 1998

Near-Infrared Galaxy Counts To J And K ∼ 24 As A Function Of Image Size, Matthew A. Bershady, James D. Lowenthal, David C. Koo

Astronomy: Faculty Publications

We have used the Keck 10 m telescope to count objects as a function of image size in two high Galactic latitude Ðelds covering 1.5 arcmin2 and reaching 50% completeness depths of K \ 24 and J \ 24.5 for stellar sources. Our counts extend D1 mag deeper in K than those of surveys with other telescopes; complement other Keck surveys in the K-band that provide counts at comparable or shallower depths but that have not utilized image structure; and extend by several magnitudes the J-band counts from brighter surveys using smaller telescopes that cover larger areas. We Ðnd the …

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Catalogs Of Temperatures And [Fe/H] Averages For Evolved G And K Stars, B. J. Taylor Sep 1998

Catalogs Of Temperatures And [Fe/H] Averages For Evolved G And K Stars, B. J. Taylor

Faculty Publications

A catalog of mean values of [Fe/H] for evolved G and K stars is described. The zero point for the catalog entries has been established by using differential analyses. Literature sources for those entries are included in the catalog. The mean values are given with rms errors and numbers of degrees of freedom, and a simple example of the use of these statistical data is given. For a number of the stars with entries in the catalog, temperatures have been determined. A separate catalog containing those data is briefly described.

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Maintenance Of Circulation Anomalies During The 1988 Drought And 1993 Floods Over The United States, Alan Z. Liu, Mingfang Ting, Hailan Wang Sep 1998

Maintenance Of Circulation Anomalies During The 1988 Drought And 1993 Floods Over The United States, Alan Z. Liu, Mingfang Ting, Hailan Wang

Physical Sciences - Daytona Beach

The large-scale circulation anomalies associated with the 1988 drought and the 1993 floods are investigated with the National Centers for Environmental Prediction Reanalysis data and a linear stationary wave model. The transient vorticity and thermal forcings are explicitly calculated and the diabatic heating is derived as a residual in the thermodynamic energy equation. Using the April–June (AMJ) data for 1988, and June–August (JJA) data for 1993, the linear stationary wave model is able to reproduce the main features of the geopotential height anomaly for the two seasons when all forcings are included. This provides a basis for further investigation of …

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Polarization Of Astronomical Maser Radiation. Iv. Circular Polarization Profiles, Moshe Elitzur Sep 1998

Polarization Of Astronomical Maser Radiation. Iv. Circular Polarization Profiles, Moshe Elitzur

Physics and Astronomy Faculty Publications

Profile comparison of the Stokes parameters V and I is a powerful tool for maser data analysis, which provides the first direct methods for unambiguous determination of (1) the maser saturation stage, (2) the amplification optical depth and intrinsic Doppler width of unsaturated masers, and (3) the comparative magnitudes of Zeeman splitting and Doppler line width. Circular polarization recently detected in OH 1720 MHz emission from the Galactic center appears to provide the first direct evidence for maser saturation.

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Comparison Of The Sfi Peculiar Velocities With The Iras 1.2-Jy Gravity Field, L. N. Da Costa, A. Nusser, W. Freudling, R. Giovanelli, M. P. Haynes, J J. Salzer, G. Wegner Sep 1998

Comparison Of The Sfi Peculiar Velocities With The Iras 1.2-Jy Gravity Field, L. N. Da Costa, A. Nusser, W. Freudling, R. Giovanelli, M. P. Haynes, J J. Salzer, G. Wegner

Dartmouth Scholarship

We present a comparison between the peculiar velocity fields measured from a recently completed I-band Tully-Fisher survey of field spirals (SFI) and that derived from the IRAS 1.2-Jy redshift survey galaxy distribution. The analysis is based on the expansion of these data in redshift space using smooth orthonormal functions, and is performed using low- and high-resolution expansions, with an effective smoothing scale which increases almost linearly with redshift. The effective smoothing scales at 3000 km s−1 are 1500 and 1000 km s−1 for the low- and high-resolution filters. The agreement between the high- and low-resolution SFI velocity …

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Emission Line Profile Shapes From Anisotropic Scattering In Planar Equatorial Disks., R. Ignace Aug 1998

Emission Line Profile Shapes From Anisotropic Scattering In Planar Equatorial Disks., R. Ignace

Richard Ignace

The consequences of anisotropic resonance line scattering for the emission profiles of equatorial disks are considered. In particular the opportunity to infer the disk velocity field owing to the anisotropic scattering is discussed. Analytic expressions for the profile shapes are derived for the cases of constant expansion and rotation, and numerical results are given for more realistic disk velocity fields of linear expansion and Keplerian rotation. The essential result is that the anisotropic line scattering produces a different profile signature in expanding disks as compared to rotating disks, owing to the difference in the isovelocity pattern of the two cases …

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Inference Of Steady Stellar Wind V(R) Laws From Optically Thin Emission Lines Iii. Inversion Of Total Line Intensity Distributions., R. Ignace, J. C. Brown, J. E. Milne, J. P. Cassinelli Aug 1998

Inference Of Steady Stellar Wind V(R) Laws From Optically Thin Emission Lines Iii. Inversion Of Total Line Intensity Distributions., R. Ignace, J. C. Brown, J. E. Milne, J. P. Cassinelli

Richard Ignace

The variation with wavelength for a sequence of total intensities of stellar wind lines is considered as a basis for deriving the wind velocity law v(r). In particular, we focus on the case where the continuum formation in the wind is dominated by the free-free opacity so that the inner radius increases with wavelength, as is realized in some massive winds like those of the Wolf-Rayet stars. The line emission in the wind occurs exterior to the continuum photosphere, hence lines observed at different wavelengths probe different regions of the wind acceleration. A major consequence of these physical conditions is …

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Detection Of Intergalactic Red-Giant-Branch Stars In The Virgo Cluster, Henry C. Ferguson, Ted Von Hippel, Nial R. Tanvir Aug 1998

Detection Of Intergalactic Red-Giant-Branch Stars In The Virgo Cluster, Henry C. Ferguson, Ted Von Hippel, Nial R. Tanvir

Publications

It has been suspected for nearly 50 years that clusters of galaxies contain a population of intergalactic stars, ripped from galaxies during cluster formation or when the galaxies’ orbits take them through the cluster center. Support for the existence of such a population of free-floating stars comes from measurements of the diffuse light in clusters and from recent detections of planetary nebulae with positions and/or velocities far removed from any observed cluster galaxy. 10 , 11 But estimates for the mass of the diffuse population and its distribution relative to the galaxies are still highly uncertain. Here we report the …

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