While apparently supplying tremendous power to their extended radio-emitting regions, the nuclei of most radio galaxies emit little detectable radiation. It is proposed that at the centre of each is a spinning black hole surrounded by a torus of gas too hot and tenuous to radiate efficiently. The torus anchors magnetic fields which extract rotational energy from the hole in the form of two collimated beams of relativistic particles and fields. These in turn drive the observed radio jets and hot spots. A large supply of accreting gas is thus unnecessary and radio galaxies may be interpreted as starved quasars.

Ion-supported tori and the origin of radio jets

https://www.cns.s.u-tokyo.ac.jp/~shimoura/research/nuc_data/pdf/11.pdf

Energy levels of light nuclei A = 11-12

Observations with the Wide-Field Camera of the Hubble Space Telescope (HST) are presented for a representative sample of 20 intrinsically luminous quasars with redshifts smaller than 0.30. These observations show that luminous quasars occur in diverse environments that include ellipticals as bright as the brightest cluster galaxies (two), apparently normal ellipticals (10), apparently normal spirals with H II regions (three), complex systems of gravitationally interacting components (three), and faint surrounding nebulosity (two). The quasar host galaxies are centered on the quasar to the accuracy of our measurements, 400 pc. There are more radio-quiet quasars in galaxies that appear to be ellipticals (seven) than in spiral hosts (three), contrary to expectations. However, three, and possibly five, of the six radio-loud quasars have detectable elliptical hosts, in agreement with expectations. The luminous quasars studied in this paper occur preferentially in luminous galaxies. The average absolute magnitude of the hosts is 2.2 mag brighter than expected for a field galaxy luminosity function. The superb optical characteristics of the repaired HST make possible the detection of close galactic companions; we detect eight companion galaxies within projected distances of 10 kpc from quasar nuclei. The presence of very close companions, the images of current gravitational interactions, and the higher density of galaxies around the quasars suggest that gravitational interactions play an important role in triggering the quasar phenomenon.

/pdf/hubble-space-telescope-images-of-a-sample-of-20-nearby-d15vlmuta0.pdf

Hubble Space Telescope Images of a Sample of 20 Nearby Luminous Quasars

In the present-day universe, supermassive black hole masses (MBH) appear to be strongly correlated with their galaxy’s bulge luminosity, among other properties. In this study, we explore the analogous relationship between MBH, derived using the virial method, and the stellar R-band bulge luminosity (LR) or stellar bulge mass (M∗) at epochs of 1 . z . 4.5 using a sample of 31 gravitationally lensed AGNs and 20 non-lensed AGNs. At redshifts z > 1.7 (10–12 Gyrs ago), we find that the observed MBH–LR relation is nearly the same (to within ∼ 0.3 mag) as it is today. When the observed LR are corrected for luminosity evolution, this means that the black holes grew in mass faster than their hosts, with the MBH/M∗ mass ratio being a factor of & 4 +21 times larger at z > 1.7 than it is today. By the redshift range 1 . z . 1.7 (8–10 Gyrs ago), the MBH/M∗ ratio is at most two times higher than today, but it may be consistent with no evolution. Combining the results, we conclude that the ratio MBH/M∗ rises with look-back time, although it may saturate at ≈ 6 times the local value. Scenarios in which moderately luminous quasar hosts at z & 1.7 were fully formed bulges that passively faded to the present epoch are ruled out. Subject headings: galaxies: evolution — galaxies: quasars — galaxies: fundamental parameters — galaxies: structure — galaxies: bulges

Probing the Coevolution of Supermassive Black Holes and Galaxies Using Gravitationally Lensed Quasar Hosts

On the origin and early evolution of terrestrial planet atmospheres and meteoritic volatiles

Host galaxies of quasars and their association with galaxy clusters.

Spectrophotometric observations of Comet Halley obtained in March 1986 at the time of the spacecraft encounters with the comet are described, and the column densities derived from the integrated emission band fluxes are presented. The scale lengths are determined from the spatial profiles of the observed species. Production rates are derived and the parent identities and abundance ratios of the studied species are discussed. The data indicate that the abundance of the primordial condensate NH3 comprises about 0.2 percent of the total volatile fraction of the comet nucleus. The ratio of production rates Q(NH2)/Q(H2O) = 0.003 indicates that Q(NH3)/Q(H2O) is roughly 0.3 percent, which is nearly 10 times lower than the value determined from Giotto ion mass spectrometer data. The production rate Q(CH)/Q(H2O) of 0.007 and the CH spatial profile indicate that CH cannot derive entirely from direct photodissociation of CH4.

Abundances in Comet Halley at the time of the spacecraft encounters

The individual (C-13)N rotational lines in Comet Halley are resolved using high-resolution spectra of the CN B2Sigma(+)-X2Sigma(+) (0,0) band The observe C-12/C-13 abundance ratio excludes a site of origin for the comet near Uranus and Neptune and suggests a condensation environment quite distinct from other solar system bodies Two theories are presented for the origin of Comet Halley One theory suggest that the comet originated 45 Gyr ago in an inner Oort cloud at a heliocentric distance greater than 100 AU where chemical fractionation led to the C-13 enrichment in the CN parent molecule prior to condensation of the comet nucleus According to the other, more plausible theory, the comet nucleus condensed relatively recently from the interstellar medium which has become enriches in C-13 and was subsequently gravitationally captured by the solar system

The C-12/C-13 abundance ratio in Comet Halley

Resolution of quasar images.

The image (excluding the jet) of 3C 273 has been resolved with structure extending approx.15'' from the quasar to a surface brightness level, m/sub R/roughly-equal25 mag arcsec/sup -2/. The integrated magnitude of the underlaying nebulosity, Rroughly-equal16, corresponds to M/sub R/roughly-equal-25, and the isophotal angular diameter to Droughly-equal90 kpc.

P. A. Wehinger

Papers

Host galaxies of quasars and their association with galaxy clusters.

Abundances in Comet Halley at the time of the spacecraft encounters

The C-12/C-13 abundance ratio in Comet Halley

Resolution of quasar images.

Discovery of nebulosity associated with the quasar 3C 273