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Space-born gravitational-wave interferometers such as {\it LISA} will detect the gravitational wave (GW) signal from the inspiral, plunge and ringdown phases of massive black hole binary mergers at cosmological distances. From the inspiral waves, we will be able to measure the masses of the binaries' members; from the ringdown waves, we will be able to measure the mass of the final merged remnant. A subset of detected events allow the identification of both the inspiral and the ringdown waveforms in a given source, and thus allow a measurement of the total mass-energy lost to GWs over the coalescence, $M_{\rm GW}$. We define ``golden'' binary mergers to be those with measurement errors likely to be small enough for a physically useful determination of $M_{\rm GW}$. A detailed sensitivity study, combined with simple black hole population models, suggests that a few golden binary mergers may be detected during a 3-year {\it LISA} mission lifetime. Any such mass deficit measurement would constitute a robust and valuable observational test of strong-field relativistic gravity. An extension of this concept to include spin measurements may allow a direct empirical test of the black hole area theorem., 18 pages, 6 figures. Accepted for publication in ApJ

The evolution of the globular cluster system in a galaxy has relevant implications on the overall galactic structure, both on a large and on a small scale. In particular, the effect of dynamical friction on massive globulars in elliptical galaxies leads to an accumulation of stellar matter in the inner galactic zone that may feed a stellar black hole to make it grow up to supermassive sizes.

The most recent results of the SgrA* near-infrared monitoring program are described. The program was started over ten years ago using the MPE speckle Camera SHARP at the ESO NTT and has now very successfully been continued with the NAOS/CONICA adaptive optics system at the ESO VLT UT4. There are confirmed and newly found accelerated motions for all together 6 stars, with 4 stars having passed the peri-center of their orbits during the observed time span. All orbits have moderate to high eccentricities. The center of these acceleration coincides with the radio position of Sgr A*. From the orbit of the star S2, the currently most tightly constrained one, one can determine the mass of Sgr A* to 3.3 ± 0.7 x 106M⨀ and its position to 2.0 ± 2.4 mas East and 2.7 ± 4.5 mas South of the nominal radio position. The mass estimates for the central dark mass from the orbit of S2 and from statistical estimators agree well within the errors. As a combined result one can estimate that > 98% of the mass contained within the orbit of S2 is contained within ~0.1 mas. This implies a mass density of >5 x 1021M⨀pc-3.

The binary relativistic stars merge rate in the Universe is determined mostly by the evolutionary scenario of the binary stars. Some of the unknown parameters of this scenario can be estimateted by the comparison of population synthesis predictions with the actually observed galactic population. We performed the Scenario Machine simulations with a revised scenario model and obtained that the lower estimate of the binary black hole merger rate should be ∼ 7 times higher than was given before.

We have used ice-flow velocity measurements from synthetic aperture radar to reassess the mass balance of the Ross Ice Streams, West Antarctica. We find strong evidence for ice-sheet growth (+26.8 gigatons per year), in contrast to earlier estimates indicating a mass deficit (−20.9 gigatons per year). Average thickening is equal to ∼25% of the accumulation rate, with most of this growth occurring on Ice Stream C. Whillans Ice Stream, which was thought to have a significantly negative mass balance, is close to balance, reflecting its continuing slowdown. The overall positive mass balance may signal an end to the Holocene retreat of these ice streams.

We investigate the hypothesis that the cores of elliptical galaxies and bulges are created from the binding energy liberated by the coalescence of supermassive binary black holes during galaxy mergers. Assuming that the central density profiles of galaxies were initially steep power laws, we define the ``mass deficit'' as the mass in stars that had to be removed from the nucleus in order to produce the observed core. We use nonparametric deprojection to compute the mass deficit in a sample of 35 early-type galaxies with high-resolution imaging data. We find that the mass deficit correlates well with the mass of the nuclear black hole, consistent with the predictions of merger models. We argue that core sizes in halos of non-interacting dark matter particles should be comparable to those observed in the stars., 5 pages, 2 postscript figures, uses emulateapj.sty. Accepted for publication in Monthly Notices of the Royal Astronomical Society

It has been suggested already a very long time ago that supermassive binary black holes (SMBBHs) may exist in the nuclei of the Active Galactic Nuclei (AGN) (e.g. Begelman, Blandford and Rees 1980). To prove this observationally is an extremely difficult task.

Extensive investigations have brought up the fact that there are still considerable amounts of ore reserves of copper mine “Bor” (at Yugoslavia), located at the slope and under the abandoned open pit mine. This paper presents the methodology of modeling the process of inducing mass deficit, the process of caving and corresponding stress-strain changes in the surrounding rock mass. The rock mass of the investigated area is composed of: extrusive magmatic rocks, pyroclastites, volcanic sediment rocks (the Bor pelites) and conglomerates. The problem of determining parameters of a rock mass constitutive relations in a large scale has been analyzed. The finite element method (FEM) is adopted as a numerical procedure. The constitutive relations of the rock strata are modeled as elastic and plastic-brittle behaviour. The effects of strain softening around the ground openings are taken into account. Key problems of the model are caving moment criterion and size of the caved zone. Assuming that physical instability coincides with numerical divergence, the criterion of the moment of caving has been introduced as initial divergence of the solution of the stress-strain problem. The results show the development process of the zones of instability as a function of the progress of the exploitation. The proposed numerical procedure combined with in-situ investigation works has many advantages over the usual empirical procedures, and can be a valuable tool to mining engineers assessing the short and long term stability of rock mass caused by underground excavition at open pit slope.

Shallow cores in bright, massive galaxies are commonly thought to be the result of scouring of stars by mergers of binary supermassive black holes. Past investigations have suggested correlations between the central black hole mass and the stellar light or mass deficit in the core, using proxy measurements of $M_{\rm BH}$ or stellar mass-to-light ratios ($\Upsilon$). Drawing on a wealth of dynamical models which provide both $M_{\rm BH}$ and $\Upsilon$, we identify cores in 23 galaxies, of which 20 have direct, reliable measurements of $M_{\rm BH}$ and dynamical stellar mass-to-light ratios ($\Upsilon_{\star,{\rm dyn}}$). These cores are identified and measured using Core-S\'ersic model fits to surface brightness profiles which extend out to large radii (typically more than the effective radius of the galaxy); for approximately one fourth of the galaxies, the best fit includes an outer (\sersic) envelope component. We find that the core radius is most strongly correlated with the black hole mass and that it correlates better with total galaxy luminosity than it does with velocity dispersion. The strong core-size-- $M_{\rm BH}$ correlation enables estimation of black hole masses (in core galaxies) with an accuracy comparable to the $M_{\rm BH}$--$\sigma$ relation (rms scatter of 0.30 dex in $\log M_{\rm BH}$), without the need for spectroscopy. The light and mass deficits correlate more strongly with galaxy velocity dispersion than they do with black hole mass. Stellar mass deficits span a range of 0.2--39 \mbh, with almost all (87%) being $< 10 \, M_{\rm BH}$; the median value is 2.2 $M_{\rm BH}$., Comment: Proof-corrected version, AJ, 146, 160, http://stacks.iop.org/1538-3881/146/160

We investigate expected gravitational wave spectrum from coalescing supermassive black hole (SMBH) binaries resulting from mergers of host galaxies. When galaxies merge, the central SMBHs sink to the center of the new merged galaxy and they finally coalesce producing low-frequency gravitational waves (GWs). Using a semi-analytic model of galaxy and quasar formations, we estimate the SMBH coalescence rate and find that the characteristic strain amplitude of the expected GW background spectrum is h c (f) ∼ 10 - 1 6 (f/yr - 1 ) - 2 / 3 just below the detection limit from measurements of pulsar timing.

We present results of numerical simulations of mergers of spiral galaxies using GADGET (Springel, Yoshida, & White 2001). In three of these simulations one of the progenitor galaxies contained a central supermassive black hole (BH), as well as one simulation which did not contain a BH. The merger remnants were evolved to an age of ∼ 13 Gyr to examine the evolution of the shape of each merger remnant. The results of these simulations were compared to observations of elliptical galaxies, which show that older galaxies appear rounder than younger ones (Ryden, Forbes, & Terlevich 2001).We found that the simulations in which the BH mass was fixed throughout the evolution influence the shape of their host galaxies on timescales less than 3 Gyr. These simulations show little trend of shape with age beyond this time. In the simulations in which the BH mass increased linearly over the duration of the simulation, there is a significant evolution of the shape of the remnant throughout its lifetime, comparable to the observational trend.

A mysterious disc at the heart of the Andromeda galaxy may explain how supermassive black holes ate enough material to bulk up to their huge sizes

We present the first estimate of the black hole mass function (BHMF) of broad-line quasars (BLQSOs) that self-consistently corrects for incompleteness and the statistical uncertainty in the mass estimates, based on a sample of 9886 quasars at 1 < z < 4.5 drawn from the Sloan Digital Sky Survey. We find evidence for “cosmic downsizing” of black holes in BLQSOs, where the peak in their number density shifts to higher redshift with increasing black hole mass. We estimate the lifetime of the BLQSO phase to be 70 ± 5 Myr for supermassive black holes (SMBHs) at z = 1 with a mass of MBH = 109M⊙, and we constrain the maximum mass of a black hole in a BLQSO to be ~ 1010M⊙. We find that most BLQSOs are not radiating at or near the Eddington limit. Our results are consistent with models for self-regulated black hole growth, where the BLQSO phase occurs at the end of a fueling event when black hole feedback unbinds the accreting gas.

We present K-band adaptive-optics assisted spectroscopic observations of the central region of the archetype head-tail radio galaxy NGC 1265 (3C 83.1), with the aim of constraining the mass of the supermassive black hole (MBH). The near-infrared data taken with the Altair–NIRI system on the Gemini North have a spatial resolution of FWHM = 0.”11 (39 pc, at the galaxy's distance of 73 Mpc).

It has become generally accepted that most or possibly all ellipticals and bulges of spirals harbor supermassive black holes in their center (see Ho 1998 for a recent review).

The geoid is becoming increasingly important in interpretation of global tectonics. Most of the topography of the earth is isostatically compensated, so removal of its effect from the geoid is appropriate before tectonic modeling. The oceanic trenches, however, are dynamically depressed features and cannot be isostatically compensated in the classical way. Continental topography compensated at 35 km gives intracontinental geoidal undulations of up to 15 m over mountain ranges in a spherical harmonic expansion to order and degree 22. Oceanic topography compensated at 40 km, reasonable for the thermally supported long wavelengths, matches the +10 m difference between old continents and old oceans in a detailed NASA/GSFC geoid. Removing the assumed compensation for the oceanic trenches leaves negative anomalies of up to 9 m amplitude caused by their uncompensated mass deficit. This mass deficit acts as a partial "regional compensation" for the excess mass of the subducting slabs, and partly explains why geoidal (and gravity) anomalies over the cold slabs are less than thermal models predict.

An enormous component of isostatic compensation (∼−430±40mgal) is provided by subcrustal material beneath the neovolcanic zone of Iceland. Previously published values for the component of gravity contributed by anomalous mantle material beneath this region range from −250 to −140 mgal. These values are only a partial indication of the magnitude of the compensation mechanism. If one takes into account constraints on crustal thickness from seismic refraction studies and compares Iceland to less active tectonic regions near by, one obtains a mantle gravity effect of approximately −430±40mgal , which for a simple slab model leads to a vertically integrated mass deficit per unit surface area of 10 6 g/cm 2 . The effects of thermal expansion, solid-solid phase transitions and partial fusion can provide significant contributions to the total mass deficiency; however, none of these mechanisms alone seems sufficient to account for the entire anomaly. The relation of this mass anomaly to the evolution of the Iceland-Faeroe ridge is considered by examining two extreme end-members of a suite of possible evolutionary models for this region. The first of these is the case where, in time, the 10 6 g/cm 2 mass deficit will be resorbed into the mantle with the effects of chemical segregation playing a minor role. The second case, which is preferred, involves a significant redistribution of material from the mantle such that basaltic melt segregated from high levels in the mantle accumulates and crystallizes in a zone at the base of the crust. In this latter model, if the Iceland-Faeroe ridge is considered to have evolved under a steady rate of magma production over the last 30–40 × 10 6 years, then underplating of the crust may account for its increasing thickness as it matures from 8–10 km in the neovolcanic zone to a value of approximately 32 km for the Iceland-Faeroe ridge. If we assume a 10% increase in density upon crystallization, thickening of the crust by 22 km through underplating by magma accumulation leads to an increase in mass per unit surface area of 0.6 × 10 6 g/cm 2 , and accounts for approximately 60% of the total mass difference in the mantle between Iceland and the Iceland-Faeroe ridge.

LOS Bouguer gravity anomalies have been calculated from a low altitude LOS free air Doppler gravity profile across northern Mare Fecunditatis, southern Mare Tranquillitatis and the Aridaeus Rille. The Hyginus-Triesnecker area has been included in model calculations, though here only free air anomalies are present. A crustal density model has been fitted to the Bouguer anomalies and to the free air anomalies in the case of the Hyginus-Triesnecker area. On a regional scale northern Fecunditatis has Bouguer anomalies up to 80 mgal and lithostatic stresses of 29 bar and thus is nearly in isostatic equilibrium. Tranquillitatis can be divided into three regions of different crustal structure: (1) northern Tranquillitatis with only minor free air gravity anomalies is more or less in isostatic balance, (2) the southeastern region with Bouguer anomalies to −100 mgal and lithostatic stresses of −73 bar has a considerable mass deficit, (3) the southwestern basin is dominated by the local structure Lamont with a Bouguer maximum of 200 mgal and extremely high lithostatic stresses of 285 bar. The Bouguer minimum of −180 mgal of the Aridaeus area has been modelled by two alternative models: (i) a crustal thickening of 33 km and associated lithostatic stresses of −164 bar, and (ii) a crustal thickening of 20 km plus a low density intrusion. The free air maximum of the Hyginus-Triesnecker area has been fitted by a mantle plug connected with stresses of 116 bar. As the old irregular maria could not sustain large mascon stresses, it has been concluded that the local high stresses of Lamont, Aridaeus, and Hyginus-Triesnecker have been evolved after the impacts of the circular maria. Intrusional activities in these areas could have proceeded to fault zones generated by the large impacts.

The pronounced positive gravity anomalies in the lunar circular maria imply lack of isostatic compensation of the lunar mascons. This lack of isostasy is hard to reconcile with the rheological properties of the lunar crust. Analysis of the negative ring anomalies that appear to surround the major positive gravity peaks indicates that associated with each mascon is a mass deficit of approximately the same size. In view of the lunar rheology these mass deficits most probably represent compensating mass deficits beneath the lunar mascon maria. Consequently, most lunar mascons appear to be near isostatic equilibrium, and the observed gravity anomalies may be essentially the superposition of positive gravity peaks due to the basaltic mare fill, and less pronounced, broader gravity lows due to the compensating mass deficits at depth.

Steady-state wind-driven circulations in a basin of variable depth, with only vertical turbulent mixing, are considered. The geostrophic flow away from the coast is determined for an arbitrary bottom topography consisting of only closed depth contours and with depth at the coast small but larger than E1/2, where E is the Ekman number. Conditions under which cross-contour geostrophic flow can occur are investigated. A coastal boundary layer of horizontal width E1/2 is required to bring the normal transport to zero on the coast. Although the layer cannot incorporate upwelling explicitly, it does bring about mass balance by transporting mass along the coast from regions of mass surplus to regions of mass deficit. A brief comparison of conventional transport models and this three-dimensional model is made.

This paper corrects Hall's work in the light of more complete experiments which have established that a thermal is merely a special case of a buoyant puff. The general theory, presented here, applies to any isolated buoyant or non-buoyant puff in shearing surroundings of uniform potential density. This theory is then applied to the case of constant mass deficit and constant wind shear, and solutions are obtained in the form of algebraic equations and simple definite integrals. When these solutions are evaluated numerically, using experimentally determined constants, it is found that the ratio of the coefficients of vertical transport of momentum and heat attributable to the puff lies in the range 0.27 σ to 0.7 σ approximately, where σ is the (small) proportion of the area of the horizontal plane through any height which is occupied by puffs. Also, realistic variation of the angle of spread of puffs is found to produce a very considerable effect on the depth of the convective layer. Only narrow puffs rise far.

Earlier photometric and spectroscopic observations of the binary BM Ori are interpreted in terms of a thin disk model for the object which causes the eclipses. It is shown that the secondary mass, about which the disk particles orbit, has small dimensions and a mass of 3 to 4m⊙, which suggests that it can only be a collapsed star. The model requires a history of mass exchange or mass loss for the binary. If the Trapezium stars have been formed with the past 2×104 yr, as some studies have indicated, a less conventional alternative, perhaps involving fragmentation of a pre-stellar mass, is needed. Further observations may make it possible to decide for certain between this and a recent model by Hall.

The determination of the mass distribution in the central few parsecs of the Galaxy, primarily from the ionized gas dynamics, is discussed. The gas motions are described and interpreted assuming that the orbits are determined by gravitational forces. It is shown that there is good evidence for a central mass of ~ 2 × 106 M⊙. The primary uncertainty in this conclusion results from the possibility of significant magnetic forces. In the absence of corroborating evidence, the case for a massive black hole cannot be considered proven.

The interaction of oxygen with Ni(110) was investigated by STM. The formation of the (2×1) and (3×1) structures, which were identified by their one-dimensional corrugation, did not involve any kind of long range mass transport. This rules out structure models exhibiting a mass deficit like e.g. “missing row” reconstructions. The two-dimensional corrugation of the (9×4) suboxide agrees with an existent model, assuming a single layer of NiO(100) on the Ni substrate, its formation involves long range mass transport and partial erosion of Ni terraces.

We have used the impulsive approximation technique to numerically estimate the effect of dynamical friction on the motion of a supermassive black hole (mass ≃ 109M⊙) through a galaxy (mass ≃ 1011M⊙) which has recoiled from the center of the latter as a result of rocket effect (anisotropic emission of gravitational radiation or plasma emission etc.) We find the effect to be minimal for recoil taking place at a velocity larger than that of escape at the center of the galaxy. For recoil velocities less than a certain critical velocity (slightly larger than the central escape velocity), dynamical friction becomes relatively pronounced and damped oscillatory motion of the black hole in the potential well of the galaxy ensues.

Recent satellite investigations revealed that in the 1990s the grounding line of Pine Island and Thwaites Glaciers, West Antarctica, retreated several km, the ice surface on the interior of the basins lowered 10 cm a–1, and Pine Island Glacier thinned 1.6 ma–1. These observations, however, were not sufficient to determine the cause of the changes. Here, we present satellite radar interferometry data that show the thinning and retreat of Pine Island Glacier are caused by an acceleration of ice flow of about 18 ± 2% in 8 years. Thwaites Glacier maintained a nearly constant flow regime at its center, but widened along the sides, and increased its 30 ± 15% mass deficit by another 4% in 4 years. The combined mass loss from both glaciers, if correct, contributes an estimated 0.08 ± 0.03 mma–1 global sea-level rise in 2000.

Supermassive black holes are expected to pair as a result of galaxy mergers, and form a bound binary at parsec or sub-parsec scales. These scales are unresolved even in nearby galaxies, and thus detection of non-active black hole binaries must rely on stellar dynamics. Here we show that these systems could be indirectly detected through the trail that the black holes leave as they spiral inwards. We analyze two numerical simulations of inspiralling black holes (equal masses and 10:1 mass ratio) in the stellar environment of a galactic centre. We studied the effect of the binary on the structure of the stellar population, with particular emphasis on projected kinematics and directly measurable moments of the velocity distribution. We present those moments as high-resolution 2D maps. As shown in past scattering experiments, a torus of stars counter-rotating with respect to the black holes exists in scales ~ 5 to 10 times larger than the binary separation. While this is seen in the average velocity map in the unequal mass case, it is obscured by a more strongly co-rotating outer region in the equal mass case; however, the inner counter-rotation could still be detected by studying the higher moments of the velocity distribution. Additionally, the maps reveal a dip in velocity dispersion in the inner region, as well as more pronounced signatures in the higher distribution moments. These maps could serve as templates for integral field spectroscopy observations of nearby galactic centres. The discovery of such signatures may help census the population of supermassive black hole binaries and refine signal rate predictions for future space-based low frequency gravitational wave detectors., Accepted for publication in MNRAS; 9 pages, 7 figures

We use the Galaxy And Mass Assembly (GAMA) survey to measure the local Universe mass dependent merger fraction and merger rate using galaxy pairs and the CAS structural method, which identifies highly asymmetric merger candidate galaxies. Our goals are to determine which types of mergers produce highly asymmetrical galaxies, and to provide a new measurement of the local galaxy major merger rate. We examine galaxy pairs at stellar mass limits down to $M_{*} = 10^{8}M_{\odot}$ with mass ratios of $$4:1) the lower mass companion becomes highly asymmetric, while the larger galaxy is much less affected. The fraction of highly asymmetric paired galaxies which have a major merger companion is highest for the most massive galaxies and drops progressively with decreasing mass. We calculate that the mass dependent major merger fraction is fairly constant at $\sim1.3-2\%$ between $10^{9.5}, Comment: Accepted for publication in MNRAS: 14 Pages, 16 Figures, 3 Tables

If able to coalesce in a Hubble time, Supermassive Black hole (SMBH) binaries are very promising sources of gravitational waves (GW). Our earlier studies have shown that SMBH binaries coalesce in post-merger galactic nuclei having triaxial or axisymmetric geometry in a few billion years. In this study, we model the complete evolution of SMBH binaries formed as a result of galaxy mergers having central density profiles that vary from shallow to very steep including a stellar mass function. Energy and angular momentum loss due to GW emission is taken into account using the post-Newtonian approximation. We carry out ten such simulations for each central density profile. The eccentricity of the SMBH binaries remain very high in shallow cusps and decrease systematically for steeper cusps. The coalescence times range from 0.6 to 1.5 Gyr with shorter times for steeper profiles. Typical coalescence times less than a Gyr strengthen our expectation that SMBH binaries should be very promising sources of GW radiation over a wide redshift range.

Magnetoturbulent kinetic energy instrumental in removal of general relativistic instability of supermassive stars

Structures of several wide-angle-tailed radio sources are calculataed under the assumption that they represent trails of moving supermassive black holes. Black holes are set in motion during mergers of galaxies and in many cases oscillate about the center of the merged galaxy for billions of years. In addition, it is assumed that the merged galaxy moves through the intergalactic medium. A good match with the brightness distributions in 3C 288 and 3C 465 is obtained, while the case of 3C 75 is more difficult to model due to its double-nucleus structure. The flip-flop model of Rudnick and Edgar (1984) is in many ways analogous to the slingshot model. 34 refs.