A possible relation between the masses of black holes in galactic nuclei and the parameters of the host galaxies

Data on about forty virialized galaxy clusters with bright central galaxies, for which both the galactic velocity dispersion (?? _gal) and the stellar velocity dispersion in the brightest galaxies (??*) are measured, have been used to obtain several approximate relations between ?? _gal, ??*, the absolute B magnitude of the brightest central galaxyM _B ^BCG , and the mass of the central massive black holeM _BH: $\begin{gathered} \log \sigma _* = (0.12 \pm 0.14)\log \sigma _{gal} + (2.1 \pm 0.4), \hfill \\ \log \sigma _* = - (0.15 \pm 0.02)M_B^{BCG} + (0.85 \pm 0.5), \hfill \\ \log M_{BH} = 0.51\log \sigma _{gal} + 7.28. \hfill \\ \end{gathered} $ . These relations can be used to derive crude estimates ofMBH in the nuclei of the brightest galaxies using the parameters of the both host galaxies and the host galaxy clusters. The last relation above confirms earlier suggestions of a quadratic relation between the masses of the coronas of the host systems and the masses their central objects: M _hg ^halo ?? M _cent ² . The relations obtained are consistent with the common evolution of subsystems with different scales and masses formed in the process of hierarchical clustering.     

Radio synchrotron emission by protons and electrons in pulsars and the nuclei of quasars

Relations enabling estimation of the limiting brightness temperature of synchrotron radiation subject to self-absorption and inverse Compton scattering are presented for the case of relativistic electrons (positrons) and protons. Analogous expressions are presented for relativistic particles moving along curved magnetic lines of force (curvature radiation) and coherent radiation by relativistic particles. These relations can be used to determine the brightness temperatures expected for the central regions of active galactic nuclei, neutron stars, and other objects that produce relativistic particles. Radiation by relativistic protons yields higher intensities, and could be a source of the highest-energy cosmic rays.     

Do the galaxies NGC 936 and NGC 3198 possess massive spheroidal subsystems?

The condition for gravitational stability of the stellar disks of the galaxies NGC 936 and NGC 3198 makes maximum disk models unacceptable. We present mass estimates for these objects' spheroidal components. The mass of the dark halo of NGC 3198, within four disk radial scale lengths, exceeds its disk mass by a factor of 1.6 to 2. The masses of the disk and spheroidal subsystem (halo + bulge), within four radial scale lengths, are approximately the same for NGC 936.     

The crustal tongue melting model and the origin of massive anorthosites

Recent detailed field studies in several anorthosite complexes have shown that anorthosites are frequently associated with weakness zones in the crust which may have favoured their emplacement at mid-crust levels. Recent experimental data have shown that the parent magma compositions of various anorthosite massifs lie on thermal highs in the relevant phase diagrams at 10–13 kbar, indicating that these magmas cannot be derived by fractionation of peridotitic mantle melts but by melting of gabbronoritic sources in the lower crust at 40–50 km depths. In the Sveconorwegian Province terne boundaries have been traced in deep seismic profiles to Moho offsets or to tongues of lower crustal material underthrust to depths higher than 40 km. In Southern Norway, we suggest that a lithospheric-scale weakness zone (the Feda transition zone?) has channelled the Rogaland anorthosites through linear delamination, asthenospheric uprise and melting of a mafic lower crustal tongue.     

A catalog of galaxies in and around the cluster A1367. Spectral studies of several galaxies

We present a catalog of galaxies in and around the cluster A1367, together with the results of a spectroscopic study of eight faint galaxies projected onto the central part of the cluster. The observations were carried out with the Boller and Chivens spectrograph of the 2m telescope of the Guillermo Haro Observatory (Cananea, Mexico). Redshifts of eight galaxies were derived from both emission and absorption lines; the redshift for one of these, derived from Hα, SII, OIII, and Hβ emission lines, is z = 0.015. The spectrum of this galaxy displays no absorption lines at z = 0.026, testifying that it is located between the observer and A1367.     

Sesquiterpenoids in sediments of a hypersaline lagoon: A possible algal origin

Core samples were collected in Lagoa Vermelha, a hypersaline lagoon located about 100 km east of Rio de Janeiro (Brazil). The sediment composition is predominantly carbonate in amounts up to 93%. Analysis of δ¹³C of the total organic matter in the sediments showed that marine organic matter predominates throughout the core (δ¹³C ranges from −15.84 to −22.64‰ vs. PDB). Organic carbon contents (TOC) ranged from 0.81 to 13.28%. A series of cadinane-type sesquiterpenoids can be recognized in the gas chromatography-mass spectrometry data. Essentially the same components are present in all the samples, with variations only in their relative abundances. The most abundant compounds are α- and β-cubebene, α- and β-cedrene, cadinenes (different isomers), α-curcumene and calamenene, with minor amounts of calarene, humulene, calacorene and cadalene. Since this lagoon is surrounded by dunes with only minor vegetation typical of this environment (grasses, small non-resinous shrubs and no forest) with no potential source for sesquiterpenoids, a terrestrial origin for these compounds is excluded and an algal origin is more consistent with the locale and the recognition of sesquiterpenoids (including cadinol) in microbial mats from the lagoon. Only the natural product precursor sesquiterpenoids are present in the microbial mats with no detectable diagenetic derivatives (e.g. calamenene and cadalene). This indicates that the compounds in the mats are from recent input and those found in the sediments are most likely derived from former algal biomass in this lagoon, a fact confirmed by the recognition of a series of diagenetic aromatic components in the sediments. Surface sediments contain n-alkanes with no even-to-odd predominance indicating that microbial activity is higher in shallower sediments. Moreover, mass fragmentograms (m/z 191) of biomarkers revealed the presence of 17α(H),21β(H)-hopanes, the mature isomers, together with their ββ precursors and low amounts of the intermediates with the βα configuration (moretanes). This indicates a contribution of mature organic matter to these immature sediments.     

Lunar deposits of possible pyroclastic origin

Glass droplets of possible pyroclastic origin are present in the lunar regolith at the Apollo 11, 15, and 17 sites. The droplets may be derived from deposits, interbedded with mare lava flows, which have been partly mixed into the regolith by impact processes. Orange glass droplets from the Apollo 17 site (spheres, ovoids, broken droplets) are both chemically and texturally homogeneous and have rare olivine phenocrysts. None of the droplets contain shock damaged crystals which are common in glass produced during meteorite impacts. The droplets are similar to those formed in terrestrial lava fountains and are here interpreted as tephra.The homogeneous glass droplets sampled at the Apollo 11, 15 and 17 sites are located on or close to mare basin rims. Vents for the youngest mare lava flows, located near basin rims, have been identified photogeologically. Dark mantle deposits, interpreted as pyroclastic blankets in some locations, and numerous rules are also present on the mare surface, near basin rims. The glass droplets, having ages nearly contemporaneous with the associated mare lavas, may be concentrated locally near such vent areas. This association is in accordance with the limited extent of ash deposits from terrestrial lava fountains (? km from the vent).     

The possible formation of massive tori in white-dwarf binary systems

Mass exchange in white-dwarf binary systems with mass ratios 0.35–0.55 and total masses exceeding the Chandrasekhar limit could lead to the disruption of the less massive component of the system and the formation of a torus around the more massive component.     

A possible role for garnet pyroxenite in the origin of the “garnet signature” in MORB

 Geochemical data have been interpreted as requiring that a significant fraction of the melting in MORB source regions takes place in the garnet peridotite field, an inference that places the onset of melting at ≥80 km. However, if melting begins at such great depths, most models for melting of the suboceanic mantle predict substantially more melting than that required to produce the 7±1 km thickness of crust at normal ridges. One possible resolution of this conflict is that MORBs are produced by melting of mixed garnet pyroxenite/spinel peridotite sources and that some or all of the “garnet signature” in MORB is contributed by partial melting of garnet pyroxenite layers or veins, rather than from partial melting of garnet peridotite. Pyroxenite layers or veins in peridotite will contribute disproportionately to melt production relative to their abundance, because partial melts of pyroxenite will be extracted from a larger part of the source region than peridotite partial melts (because the solidus of pyroxenite is at lower temperature than that of peridotite and is encountered along an adiabat 15–25 km deeper than the solidus of peridotite), and because melt productivity from pyroxenite during upwelling is expected to be greater than that from peridotite (pyroxenite melt productivity will be particularly high in the region before peridotite begins melting, owing to heating from the enclosing peridotite). For reasonable estimates of pyroxenite and peridotite melt productivities, 15–20% of the melt derived from a source region composed of 5% pyroxenite and 95% peridotite will come from the pyroxenite. Most significantly, garnet persists on the solidus of pyroxenite to much lower pressures than those at which it is present on the solidus of peridotite, so if pyroxenite is present in MORB source regions, it will probably contribute a garnet signature to MORB even if melting only occurs at pressures at which the peridotite is in the spinel stability field. Partial melting of a mixed spinel peridotite/garnet pyroxenite mantle containing a few to several percent pyroxenite can explain quantitatively many of the geochemical features of MORB that have been attributed to the onset of melting in the stability field of garnet lherzolite, provided that the pyroxenite compositions are similar to the average composition of mantle-derived pyroxene-rich rocks worldwide or to reasonable estimates of the composition of subducted oceanic crust. Sm/Yb ratios of average MORB from regions of typical crustal thickness are difficult to reconcile with derivation by melting of spinel peridotite only, but can be explained if MORB sources contain ∼5% garnet pyroxenite. Relative to melting of spinel peridotite alone, participation of model pyroxenite in melting lowers aggregate melt Lu/Hf without changing Sm/Nd ratios appreciably. Lu/Hf-Sm/Nd systematics of most MORB can be accounted for by melting of a spinel peridotite/garnet pyroxenite mantle provided that the source region contains 3–6% pyroxenite with ≥20% modal garnet. However, Lu/Hf-Sm/Nd systematics of some MORB appear to require more complex melting regimes and/or significant isotopic heterogeneity in the source. Another feature of the MORB garnet signature, (²³⁰Th)/(²³⁸U)>1, can also be produced under these conditions, although the magnitude of (²³⁰Th)/(²³⁸U) enrichment will depend on the rate of melt production when the pyroxenite first encounters the solidus, which is not well-constrained. Preservation of high (²³⁰Th)/(²³⁸U) in aggregated melts of mixed spinel peridotite/garnet pyroxenite MORB sources is most likely if the pyroxenites have U concentrations similar to that expected in subducted oceanic crust or to pyroxenite from alpine massifs and xenoliths. The abundances of pyroxenite in a mixed source that are required to explain MORB Sm/Yb, Lu/Hf, and (²³⁰Th)/(²³⁸U) are all similar. If pyroxenite is an important source of garnet signatures in MORB, then geochemical indicators of pyroxenite in MORB source regions, such as increased trace element and isotopic variability or more radiogenic Pb or Os, should correlate with the strength of the garnet signature. Garnet signatures originating from melts of the garnet pyroxenite components of mixed spinel peridotite/garnet pyroxenite sources would also be expected to be stronger in regions of thin crust. Received: 15 February 1995/Accepted: 7 February 1996     

A spectral analysis of microlensing variability of quasars

A procedure for calculating two-dimensional power spectra of microlensing magnification fields is presented. In the absence of a shift, the one-dimensional projections of the power spectra P(k) corresponding to the light curve of a point source moving in a linear trajectory can be approximated by the expression (a ² + k ²)^?1/2 (where a = const). The power spectrum of an extended source is treated like the product of the power spectrum of a point source and the power spectrum of the brightness distribution of the extended source. The effect of the extent of the source is that it acts like a filter, suppressing high-frequency components in the spectrum. Based on eight years of monitoring of the quad gravitational lens Q2237+0305 by the OGLE group, power spectra for all four images are constructed and the (temporal) size of the radiating region of the quasar in the V filter is estimated to be 24 ± 6 days; given the constraints on the transverse velocity of the lensing galaxy (<600 km/s), the linear size turns out to be <10¹⁵ cm.     

A possible origin of uranium deposits in granites in special reference to the formation of SL deposit

The tectonic destruction and hydrothermal alteration of the H granite massif resulted in the formation of the green alteration zone. During this process, infiltrating hydrothermal solutions would resorb uraninite in the rocks, leading to the mobilization and thus migration of uranium into fissures and grain interstices, or being adsorbed on clay minerals. As a result, the medium and space were provided for later mineralization. In the Cretaceous period, the upper part of the green alteration zone underwent strong oxidation, followed by the resorption and then the transformation of metallicsulfides into limonite and hydrogeothite. And uranium present both in uraninite and in fissures was further mobilized and concentrated to form uranium ore deposits of economic importance in the redox boundary between the green zone and the purple zone.     

Study of the physical conditions in active galactic nuclei. Physical conditions in the cores of two nearby radio galaxies

We have carried out a search for compact radio sources in the cores of 16 nearby radio galaxies. We detected compact components in four radio galaxies, and found upper limits for the flux density in compact components in ten radio galaxies. VLBI observations enabled the detection of a turnover in the spectra of the two nearby radio galaxies 3C 111 and 3C 465. Using a method based on an inhomogeneous model for a synchrotron source, we estimate the magnetic-field strength and the energy densities in the magnetic field and relativistic electrons in the cores of these radio galaxies. Strong inhomogeneity in the distribution of the magnetic fields in the cores of 3C 111 and 3C 465 is implied by our analysis. The magnetic-field strengths in the central regions of these galactic nuclei, on scales of ～0.1 pc, exceed the mean strength by four to five orders of magnitude, and lie in the range 10² G < H < 10⁴ G.     

Geochemistry and possible origin of petroleum in Palaeozoic reservoirs from Halahatang Depression

The Halahatang Depression in the Tabei Uplift of the Tarim basin is an active exploration area because it has substantial reservoir potential and contains or is near to many commercial oil fields. Geochemical analysis indicates that Halahatang oils were derived from marine carbonate source rocks deposited under anoxic reducing conditions. The maturities for Halahatang oils are corresponding to the peak of the oil window and slightly higher than the neighboring Tahe oils. The Halahatang oils feature low Pr/Ph, C₂₁/C₂₃ tricyclic terpane and, C₂₈/C₂₉ sterane ratios, high C₂₉/C₃₀ hopane and C₃₅/C₃₄ hopane ratios, a “V” shape in the distribution of C₂₇–C₂₈–C₂₉ steranes and light carbon isotope ratios, similar to the Tahe oils and correlate well with the Middle-Upper Ordovician source rock. However, some source-related biomarker parameters imply a more reducing source organofacies with more zooplanktonic contribution than that for the Tahe oils.     

Hotspot origin of the Mississippi embayment and its possible impact on contemporary seismicity

Previous authors have related the Late Cretaceous/early Tertiary subsidence of the Mississippi embayment to the opening of the Gulf of Mexico, but the Gulf opened earlier in Triassic/Jurassic time. We offer an alternative hypothesis that development of the embayment was coeval with the passage of the Mississippi Valley graben system over the Bermuda hotspot about 90 Ma. Several lines of evidence of significant uplift of the embayment axis accompanying mid-Cretaceous magmatism and prior to Late Cretaceous subsidence support this proposal.

First, reactivation of the Pascola arch in the northern embayment is recorded by flanking deposits of basal Upper Cretaceous gravel. Second, beneath a regional mid-Cretaceous unconformity, subcrops of Jurassic and Early Cretaceous strata define a pronounced southwest-plunging arch in the southern embayment. This arch is collinear with an arch revealed in Paleozoic rocks after restoration to mid-Cretaceous structural geometries. Third, a deep weathering profile on mid-Cretaceous alkalic plutons along the western embayment margin is nonconformably overlain by Paleocene sediments, and rapid mid-Cretaceous cooling of these intrusions has been interpreted from apatite fission tracks. Moreover, exploratory holes along the embayment axis encountered similar weathered alkalic intrusions nonconformably overlain by basal Upper Cretaceous strata. Fourth, there was an anomalous influx of clastic sediment into the northern Gulf of Mexico during mid-Cretaceous time, and subsequent clastic facies patterns suggest the Mississippi River drainage began to enter the Gulf in the Late Cretaceous.

Passage of the Mississippi Valley graben over the Bermuda hotspot during elevated hotspot activity of Cretaceous time may have significantly weakened the previously rifted lithosphere. Rifted continental margin at Charleston, South Carolina, also passed over this hotspot in latest Cretaceous time. Similarly, the St. Lawrence rift system passed over the Great Meteor hotspot during the Cretaceous. It is important to note that these rift systems are the principal loci of strong seismicity in eastern North America, and thus weakening by increased Cretaceous hotspot activity may be an important common factor for these seismic rift zones.     

High-velocity stars as a result of encounters between stars and massive binary black holes in galactic nuclei

Numerical simulations of the motions of stars in the gravitational fields of binary black holes with various component mass ratios have been carried out. Two models are considered: (1) the two-body problem with two fixed centers; (2) the general three-body problem. The first model is applicable only over short times Δt ? T, where T is the period of the binary system. The second model is applicable at all times except for during close encounters of stars with one of the binary components, r ≤ 0.00002 pc, where r is the distance from the star to the nearer black hole. In very close passages, relativistic corrections must be taken into account. Estimates of the probability of formation of high-velocity stars as a result of such interactions are obtained. It is shown that this mechanism is not suitable for the nucleus of our Galaxy due to the probable absence of a second massive black hole in the central region of the Galaxy.     

Physical origins for variations in the apparent positions of quasars

The physical origins of the apparent motion of radio sources in the ICRF are considered. The sources can be divided into four groups, according to the characteristics of their motion. Here, we consider the model for the motion of the first group of sources—those displaying uniform linear motion. Since the apparent speeds of the radio sources are close to, and sometimes exceeding, the speed of light, it is natural to suppose that these sources are relativistic jets or plasma clouds moving with speeds close to the speed of light. Uniform linear motion can be explained by a model invoking precession of the jet. We consider the physical characteristics of a number of selected sources of the ICRF in the proposed model.     

Field and geochemical characteristics of the Coolac Ophiolite suite and its possible origin in a marginal sea

Geological and geochemical data from the Coolac Serpentinite Belt, North Mooney Complex and Honeysuckle Beds in southern New South Wales indicate that the association represents a partially dismembered ophiolite suite. All the ideal ophiolite units are present, although the sheeted dyke unit is apparently of limited extent. Major and trace element (including rare‐earth) results, relationships of mafic volcanics and dolerite to massive and layered gabbroic and ultramafic intrusives, the occurrence of tectonised harzburgite with podiform chromitite, and the nature of pyritic sulphide occurrences, are consistent with a marginal sea or back‐arc environment for the generation of the ophiolite suite.     

The nature of active radio galaxies in the cluster A569

We investigate the nature of bright radio sources with known radio spectra in the direction of the nearby cluster of galaxies A569 (z=0.0193). The optical identifications of the sources show that 45% of these radio sources are associated with compact galaxies. A substantial fraction of these galaxies have active nuclei, with the radio emission concentrated toward the galactic center. Some of the cluster galaxies have radio halos, with appreciably weaker radio powers and spectral indices α=0.95±0.2. We compute the magnetic fields in the nuclei and halos of the galaxies for the adopted distance to A569. As expected, the magnetic fields in the galactic halos make a smooth transition to the intergalactic field, while the magnetic fields in the central regions of the galaxies rise sharply toward the nucleus.     

Continental weathering as a possible origin of vein-type uranium deposits

Geochemical and geochronological data presently available, concerning pitchblende vein-type deposits in France, seem altogether too contradictory for use in building a genetic model. Mostly hydrothermal hypotheses have however been suggested, although the previously mentioned idea of formation through continental weathering remains quite relevant; indeed, it may be noted that: a) Uraniferous areas are predominantly connected with granites where geochemical uranium, found as uraninite, can easily be leached through slight weathering, in the absence of any vegetation, along with Si, Al, Na and Ca. b) Apart from Na, these are elements essentially found in mineral deposits of pitchblende with a quartz, clay or calcite matrix. c) Such weathering conditions occurred during the Permian period, about 245 million years ago, at which time these mineralizations may have been laid (geochronology U-Pb); d) Veined pitchblende deposits show much analogy in their mineral associations and sequences to the uraniferous concentrations from superficial sources, as is the case with certain deposits in the United States, formed by the circulation of vadose waters. If such a model proves correct, this type of deposit would be contemporaneous with red-bed series whose presence could then become a valuable guide-line for regional-scale exploration.     

Molar gas ratios of air entrapped in ice: A new tool to determine the origin of relict massive ground ice bodies in permafrost

The molar ratios of atmospheric gases change during dissolution in water due to differences in their relative solubilities. We exploited this characteristic to develop a tool to clarify the origin of ice formations in permafrost regions. Extracted from ice, molar gas ratios can distinguish buried glacier ice from intrasedimental ground ice formed by freezing groundwaters. An extraction line was built to isolate gases from ice by melting and trapping with liquid He, followed by analysis of N₂, O_2,, Ar, ¹⁸O_O2 and ¹⁵N_N2, by continuous flow mass spectrometry. The method was tested using glacier ice, aufeis ice (river icing) and intrasedimental ground ice from sites in the Canadian Arctic. O₂/Ar and N₂/Ar ratios clearly distinguish between atmospheric gas in glacial ice and gases from intrasedimental ground ice, which are exsolved from freezing water. δ¹⁵N_N2 and δ¹⁸O_O2 in glacier ice, aufeis ice and intrasedimental ground ice do not show clear distinguishing trends as they are affected by various physical processes during formation such as gravitational settling, excess air addition, mixing with snow pack, and respiration.