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Ionized gas galactic cluster stabilization model construction, considering ionizing radiation enhanced cosmic flux and quasar PKS 1116 plus 12 absorption spectrum
This videotape has seven segments, discussing and showing the evidence for the proposition that the galactic clusters do not have many planets. Specifically the segments show: (1) Dr. Ron Gilliland discussing the process of looking for "Hot Jupiters" (i.e., planets about the size of Jupiter, which are hotter than Jupiter) in the globular clusters, (2) a zoom into 47 Tucanae globular cluster, (3) an animation of a planet passing between the host star and the earth with a brightness graph, (4) the same animation as before without the graph, (5) Ron Gilliland of the Space Telescope Science Institute (STScI) discussing possible interpretations of his findings in the 47 Tucanae globular cluster, (6) Ron Gilliland examining the images of 47 Tucanae, and (7) images of 47 Tucanae watching for variations in brightness.
Imaging observations from the Einstein Observatory are used to determine properties of galactic clusters and the intracluster gas. The hydrostatic-isothermal gas model is applied to obtain the cluster core radius, the limiting slope of the X-ray surface brightness distribution, and the presence and magnitude of a central luminosity excess above that predicted from the model when fit to the outer regions of the cluster. It is concluded that clusters can be divided into two basic families, one with small core radii and X-ray emission centered on a central dominant galaxy, and one with larger core radii and generally no central, stationary bright galaxy. The former type probably begins to form in the early stages of a cluster's dynamical evolution. The intracluster gas has a larger scale height than that of the galaxies based on the fit of the hydrostatic-isothermal model to the X-ray surface brightness profiles.
Einstein imaging observations of four X-ray clusters of galaxies characterized by a double X-ray surface brightness and thus mass distribution are presented. The clusters A98, A115, A1750 and SC 0627-54 were found to exhibit two enhancements in their X-ray surface brightness distributions in observations made with the Einstein Imaging Proportional Counter. Calculations of the probability that the clusters represent chance superpositions indicate that the double clusters are physically associated. The radial distributions of the components are inconsistent with those of single point sources, and have been used to derive cluster luminosities which are typical of rich clusters. Masses of the subclusters are also found to be typical of bound and virialized clusters with gas contributing 10%. Within the framework of the hierarchical theory of galactic clustering, the double clusters are suggested to represent an intermediate evolutionary stage before the merger of subclusters into a relaxed Coma-type cluster.
BLAST is the Balloon-borne Large-Aperture Sub-millimeter Telescope. It will fly from a Long Duration Balloon (LDB) platform from Antarctica. The telescope design incorporates a 2 m primary mirror with large-format bolometer arrays operating at 250, 350 and 500 microns. By providing the first sensitive large-area (10 sq. deg.) sub-mm surveys at these wavelengths, BLAST will address some of the most important galactic and cosmological questions regarding the formation and evolution of stars, galaxies and clusters. Galactic and extragalactic BLAST surveys will: (1) identify large numbers of high-redshift galaxies; (2) measure photometric redshifts, rest-frame FIR luminosities and star formation rates thereby constraining the evolutionary history of the galaxies that produce the FIR and sub-mm background; (3) measure cold pre-stellar sources associated with the earliest stages of star and planet formation; (4) make high-resolution maps of diffuse galactic emission over a wide range of galactic latitudes. In addition to achieving the above scientific goals, the exciting legacy of the BLAST LDB experiment will be a catalogue of 3000-5000 extragalactic sub-mm sources and a 100 sq. deg. sub-mm galactic plane survey. Multi-frequency follow-up observations from SIRTF, ASTRO-F, and Herschel, together with spectroscopic observations and sub-arcsecond imaging from ALMA are essential to understand the physical nature of the BLAST sources.
A complete redshift survey of nearby rich galactic clusters is analyzed in terms of a spatial correlation function, the growth of supercluster, the presence of superclusters around the Bootes void and the discovery of a 300 Mpc void. Abell's (1958) statistical sampling of rich clusters is used for the study. Attention is given to the dependence of the correlation function on the richness of the system, with finding that chances are greater of finding rich neighbors closer together than poor neighbors. Samples of redshifts of 4 or less correlate well with clusters of redshift 5 or more. The size of intergalactic voids is proportional to the surrounding galactic excesses. Finally, the superclusters exist on scales of about 100 Mpc/h, which is larger than expected.
The results of an analysis of the HEAO 1 hard X-ray measurements of the Coma, A1367, and A2319 galactic clusters are presented. All three clusters have been observed to have diffuse, extended radio emission in their central regions. The results are analyzed together with radio measurements to determine the energetic electron density and the strength of the mean intracluster magnetic field in these clusters. The results show that there is no clear evidence for nonthermal flux in the spectra of the three clusters at the sensitivity limit of the low energy detectors used.
New CCD photometry of the faint, compact star cluster IC 1257 (L = 17? = +/- 15?obtained with the Palomar 5m telescope, reveals that it is a highly reddened globular cluster well beyond the Galactic center.
We present a catalogue of surface-brightness profiles (SBPs) of 125 Galactic globular clusters, the largest such collection ever gathered. The SPBs are constructed from generally inhomogeneous data, but are based heavily on the Berkeley Global Cluster Survey of Djorgovski & King. All but four of the SBPs have photometric zero points. We derive central surface brightness, King-model concentrations, core radii, half-light, and other fraction-of-light radii where data permit, and we briefly discuss their use.
Radial velocities have been obtained for six of nine stars identified on the basis of similar distances and common, extreme transverse velocities in the proper motion survey of Majewski (1992) as a candidate halo moving group at the north Galactic pole. These radial velocities correspond to velocities perpendicular to the Galactic plane which span the range -48 +/- 21 to -128 +/- 9 km/sec (but a smaller range, -48 +/- 21 to -86 +/- 19 km/sec, when only our own measurements are considered), significantly different than the expected distribution, with mean 0 km/sec, for a random sample of either halo or thick disk stars. The probability of picking such a set of radial velocities at random is less than 1%. Thus the radial velocity data support the hypothesis that these stars constitute part of a halo moving group or star stream at a distance of approximately 4-5 kpc above the Galactic plane. If real, this moving group is evidence for halo phase space substructure which may be the fossil remains of a destroyed globular cluster, Galactic satellite, or Searle & Zinn (1978) 'fragment.'
Axial ratios and major-axis orientations determined from image processing of Palomar and SRC Sky Survey material are tabulated for a sample of 100 Galactic globular clusters. From a subsample of 99 clusters, the mean axial ratio is found to be 0.93 + or - 0.01. Given that only 32 percent are flatter than b/a less than 0.9, and 5 percent flatter than 0.8, the clusters are found to be quite spherical. As predicted by King (1961 and 1966), tidal interactions by the Galaxy on the cluster are not the means by which the observed ellipticities are produced. Rather, Galactic absorption effects may have a moderate but not dominant effect on the clusters' observed ellipticities, as suggested by van den Bergh (1984). The alternate mechanisms of cluster rotation or anisotropic internal velocity distributions, or both, are considered to be more likely. The observed distribution of axial ratios is statistically indistinguishable from that of a similar-size sample of rotationally flattened clusters, which have axial-ratio values lying in the range of 0.75 less than b/a less than 0.83, and the major axes of which are oriented randomly in space.
Observations of the structure of the X-ray emission from 12 nearby rich clusters of galaxies are presented and interpreted in terms of dynamic cluster evolution. X-ray structures revealed by the Einstein Observatory imaging proportional counter in the range 0.25 to 3.0 keV were analyzed and used to classify the clusters based on their X-ray morphologies. Four categories are observed, consisting of spiral-rich clusters with low X-ray temperatures and velocity dispersions with broad and highly clumped emission, spiral-poor clusters with high X-ray temperatures and velocity dispersions with smoothly varying emission broadly or sharply peaked around a dominant galaxy, and clusters with emission typical of a cD galaxy in a poor cluster or group. The broad, highly clumped cluster emission is interpreted as a result of an early evolutionary stage, while the cD and centrally enhanced emissions represent successive later stages in X-ray galactic cluster evolution.
Techniques for verifying the spectrum defined by Woody and Richards (WR, 1981), which serves as a base for dust-distorted models of the 3 K background, are discussed. WR detected a sharp deviation from the Planck curve in the 3 K background. The absolute intensity of the background may be determined by the frequency dependence of the dipole anisotropy of the background or the frequency dependence effect in galactic clusters. Both methods involve the Doppler shift; analytical formulae are defined for characterization of the dipole anisotropy. The measurement of the 30-300 GHz spectra of cold galactic dust may reveal the presence of significant amounts of needle-shaped grains, which would in turn support a theory of a cold Big Bang.
Upper limits on the angular correlation function, w(theta), of gamma-ray bursts are obtained which constrain the sources to be very nearby or very distant. The angular clustering properties of the sources in two recent gamma-ray burst catalogs (Golenetskii et al., 1986 and Atteia et al., 1987) have been derived by determining their two-point w(theta) values, and the correlations of both data sets are consistent with w(theta) = 0. It is shown that if the spatial correlation of gamma-ray bursts resembles that of galaxies or galactic clusters, present gamma-ray burst catalogs must be complete to distances in excess of 100 Mpc, while if gamma-ray bursts are associated with a Galactic disk population, then the upper limits on w(theta) constrain the sampling depth to less than two disk scale heights.
It is shown here that an elevated rate of star formation may be responsible for burning out protogalaxies in the densest galaxy clusters, leading to the formation of candidate gravitational lenses and to an enhanced probability of close association of quasars in regions of apparently low galaxy density. Extreme tidal interactions occurring during the initial collapse of such clusters would stimulate the star formation and also could drive molecular clouds and stars onto radial orbits, fuelling massive black holes and leading to an enhanced frequency of occurrence of quasar pairs. It is argued that a fundamental bias exists against detecting luminous matter in the great galactic clusters.
The impact of high-resolution, high-sensitivity X-ray measurements obtained by the Einstein Observatory (HEAO-2) on various areas of astronomical research is discussed. Following a review of the Einstein instruments based on grazing incidence focusing X-ray optics, including the telescope, imaging detectors and spectrometers, consideration is given to observations of X-ray emission from stellar systems, galaxies, and clusters of galaxies. Einstein results concerning the X-ray luminosities of young O, B and A stars and late K and M stars, the temperature, composition and distribution of material ejected in supernova explosions and comprising the interstellar medium, the formation and evolution of stellar systems and galaxies, the energy source of quasars and active galactic nuclei and the mass distribution in galactic clusters are indicated. Substantial progress made possible by the high-resolution observations of the diffuse X-ray background in cosmological research is also noted.
This paper presents the results of the photometric calibration of the F583W filter in the astrometer Fine Guidance Sensor on the Hubble Space Telescope. Dozens of observations of the 9.58 mag Fine Guidance Sensor (FGS) transfer mode reference star Upgren 69 (in the cluster NGC 188) have been utilized to verify the consistency and demonstrate the temporal stability of the photomultipliers. The measurements which provided the material for a transformation from the FGS instrumental system to the Johnson V magnitude consisted of the extensive position mode observations performed during the Optical Field Angle Distortion calibration. A total of 588 measurements of 92 stars in the galactic cluster M35 were performed. Johnson V band photometry with a precision (i.e., random errors) of plus or minus 0.05 mag is available with an accuracy (i.e., systematic errors) of 0.05 mag over 2 yr.
Numerical studies were performed on the dynamical effects on the evolution of clumps, filaments, voids, and galaxy clusters by various final Omega values. The final Omega values examined ranged from 0.03-1, and attention was given to defining observations of superclusters which would aid in determining an actual value for Omega. The numerical trials consisted of n-body integration programs governed by the total expansion and final Omega value and included comparisons between results for open and closed universes. All runs started from the same initial conditions. The dispersion trajectories of particles and the final galactic cluster forms were found to be equivalent, regardless of the final Omega value. The possibility of deriving a value for Omega from velocity data on galaxies which have not yet joined clusters is discussed.