Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · astro-ph/9804242

HST Observations of the QSO pair Q1026-0045A,B

Patrick Petitjean·Jean Surdej·Alain Smette·Peter Shaver·Jan Muecket·Marc Remy
View original source ↗Read source document ↗Export metadata ↓

Abstract

The spatial distribution of the Ly$α$ forest is studied using new HST data for the quasar pair Q~1026--0045 A and B at $z_{em}$ = 1.438 and 1.520 respectively. The angular separation is 36 arcsec and corresponds to transverse linear separations between lines of sight of $\sim300h^{-1}_{50}$ kpc ($q_{o}$ = 0.5) over the redshift range 0.833 < z < 1.438. From the observed numbers of coincident and anti-coincident Ly$α$ absorption lines, we conclude that, at this redshift, the Ly$α$ structures have typical dimensions of $\sim500h^{-1}_{50}$ kpc, larger than the mean separation of the two lines of sight. The velocity difference, $ΔV$, between coincident lines is surprisingly small (4 and 8 pairs with $ΔV < 50 and 200 km/s respectively). Metal line systems are present at $z_{abs}$ = 1.2651 and 1.2969 in A, $z_{abs}$ = 0.6320, 0.7090, 1.2651 and 1.4844 in B. In addition we tentatively identify a weak Mg II system at $z_{abs}$ = 0.11 in B. It is remarkable that the $z_{abs}$ = 1.2651 system is common to both lines of sight. The system at $z_{abs}$ = 1.4844 %is probably associated and has strong O~VI absorption. There is a metal-poor associated system at $z_{abs}$ = 1.4420 along the line of sight to A with complex velocity profile. We detect a strong Ly$α$ absorption along the line of sight to B redshifted by only 300 km/s relatively to the associated system. It is tempting to interpret this as the presence of a disk of radius larger than 300$h^{-1}_{50}$ kpc surrounding quasar A.

Explore related subjects

astro-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Patrick Petitjean, Jean Surdej, Alain Smette, Peter Shaver, Jan Muecket, Marc Remy. 1998-04-23. HST Observations of the QSO pair Q1026-0045A,B. https://arxiv.org/abs/astro-ph/9804242

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2023

Scaling of Black Hole Accretion Discs from Gamma-Ray Bursts and Black Hole X-Ray Binaries to Active Galactic Nuclei

I consider how physical processes scale over eight orders of magnitude in black hole mass, from stellar masses in gamma-ray bursts (GRB) and black-hole X-ray binaries (BHXRB) to supermassive active galactic nuclei (AGN). Accretion rates onto stellar mass black holes range over more than sixteen orders of magnitude, from the lower luminosity BHXRB to GRB. These enormous parameter ranges correspond to qualitative as well as quantitative differences in behavior. The fundamental questions involve the balance between nonequilibrium and thermalized plasmas. When energy fluxes exceed a critical value $\sim 10^{29}$ erg/cm$^2$s, as in GRB, a black-body equilibrium pair plasma forms. At the lower fluxes found in AGN, BHXRB and microquasars, accretion power electrodynamically accelerates a small number of very energetic particles, explaining their non-thermal spectra and the high energy gamma-ray emission of blazars. Ultra-high energy cosmic rays may be accelerated by massive black holes, otherwise undetectable, with very low thermal luminosities. New-born fast high-field pulsars may be in the black-body equilibrium regime, resembling SGR in permanent outburst. I also consider the question, significant for the acceleration of nonthermal particles in GRB outflows, of whether collisionless plasmas interpenetrate rather than forming hydrodynamic shocks, and propose this as an alternative to internal shock models of GRB. A new appendix attempts to explain why AGN are, proportionally, more efficient accelerators of energetic particles than stellar mass black holes.

astro-ph↗
arXiv2022

Two 3-Branes in Randall-Sundrum Setup and Current Acceleration of the Universe

Five-dimensional spacetimes of two orbifold 3-branes are studied, by assuming that {\em the two 3-branes are spatially homogeneous, isotropic, and independent of time}, following the so-called "bulk-based" approach. The most general form of the metric is obtained, and the corresponding field equations are divided into three groups, one is valid on each of the two 3-branes, and the third is valid in the bulk. The Einstein tensor on the 3-branes is expressed in terms of the discontinuities of the first-order derivatives of the metric coefficients. Thus, once the metric is known in the bulk, the distribution of the Einstein tensor on the two 3-branes is uniquely determined. As applications, we consider two different cases, one is in which the bulk is locally $AdS_{5}$, and the other is where it is vacuum. In some cases, it is shown that the universe is first decelerating and then accelerating. The global structure of the bulk as well as the 3-branes is also studied, and found that in some cases the solutions may represent the collision of two orbifold 3-branes. The applications of the formulas to the studies of the cyclic universe and the cosmological constant problem are also pointed out.

astro-ph↗
arXiv2022

A Revolution in Science: the Eclipse Expeditions of 1919

The first direct experimental test of Einstein's theory of general relativity involved a pair of expeditions to measure the bending of light at a total solar eclipse that took place one hundred years ago, on 29 May 1919. So famous is this experiment, and so dramatic was the impact on Einstein himself, that history tends not to recognise the controversy that surrounded the results at the time. In this article, I discuss the experiment in its scientific and historical background context and explain why it was, and is, such an important episode in the development of modern physics.

astro-ph↗