AGNs,X-ray background and the possible candidates for great attractor

In the five last years, different structures (density excess 1) have been proposed as the direct cause of our infall toward the direction of Hydra—Centaurus with a velocity of 500 km s^–1. The direct effect of the mentioned matter accumulations on the X-ray background (XRB) can be estimated as a function of the geometry of the structures and of the cosmological evolution of the sources emitting in the X-ray band (2–10 keV) for different universes (₀1). If the XRB comes mostly from AGNs with low luminosity (L _X <10⁴³ erg s^–1 and, therefore, they will have a weak cosmological evolution) and we consider the difference between the intensities coming from both hemispheres (that oriented toward the direction of our motion and the opposite one) obtained by means of different satellites, we can conclude that some candidates are highly unlikely.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain     

New dimensions in world shipbuildingNeue größenordnungen im welt-schiffbauNouvelles dimensions dans le monde des constructions navales

New classes of bulk carriers and general cargo vessels are becoming more specialized and larger. The trend towards containerizing cargo has spurred construction of the large cellular containership, the roll-on/roll-off vessel, and the barge carrying ship (LASH). Bulk vessels, especially tankers, have undergone tremendous increases in size until few of the newer ones can pass through the Suez Canal. Crews have not increased primarily because of greater use of shipboard automation devices. Few ports have sufficient water depths to accommodate supertankers, necessitating more off-loading at sea and construction of new deep water terminals. Japanese yards dominate world supership construction, with Scandinavian shipyards most important in Europe. Substantial supership construction is taking place in southern Europe and is an indication of the recent economic growth of Italy, Spain and Yugoslavia. Supership construction in Great Britain has declined relative to Scandinavian and Japanese production and that in the United States is of little significance worldwide.     

Gravitationally lensed QSOs in the ISSIS/WSO-UV era

Gravitationally lensed QSOs (GLQs) at 1≤z≤2 play a key role in understanding the cosmic evolution of the innermost parts of active galaxies (black holes, accretion disks, coronas and internal jets), as well as the structure of galaxies at intermediate redshifts. With respect to studies of normal QSOs, GLQ programmes have several advantages. For example, a monitoring of GLQs may lead to unambiguous detections of intrinsic and extrinsic variations. Both kinds of variations can be used to discuss central engines in distant QSOs, and mass distributions and compositions of lensing galaxies. In this context, UV data are of particular interest, since they correspond to emissions from the immediate surroundings of the supermassive black hole. We describe some observation strategies to analyse optically bright GLQs at z∼1.5, using ISSIS (CfS) on board World Space Observatory-Ultraviolet.     

Short time-scale fluctuations in the difference light curves of QSO 0957+561A,B: microlensing or noise?

From optical R -band data of the double quasar QSO 0957+561A,B, we made two new difference light curves (with an overlap of about 330 d between the time-shifted light curve for the A image and the magnitude-shifted light curve for the B image). We observed noisy behaviours around the zero line and no short time-scale events (with a duration of months), where the term 'event' refers to a prominent feature that may be a result of microlensing or another source of variability. Only one event lasting two weeks and rising −33 mmag was found . Measured constraints on the possible microlensing variability can be used to obtain information on the granularity of the dark matter in the main lensing galaxy and the size of the source. In addition, one can also test the ability of the observational noise to cause the rms averages and the local features of the difference signals. We focused on this last issue. The combined photometries were related to a process consisting of an intrinsic signal plus a Gaussian observational noise. The intrinsic signal has been assumed to be either a smooth function (polynomial), a smooth function plus a stationary noise process, or a correlated stationary process . Using these three pictures without microlensing, we derived some models totally consistent with the observations. We finally discussed the sensitivity of our telescope (at Teide Observatory) to several classes of microlensing variability.     

Crowded-field image simulator for WSO-UV/ISSIS: first functional version developed by the Glendama team

We are developing a web-based interactive software to simulate crowded-field imaging with ISSIS on board the future WSO-UV. This new tool is aimed to prepare WSO-UV/ISSIS proposals to observe multicomponent targets and dense fields. For a given combination of UV channel, filters and exposure time, the user creates a set of point-like and extended sources (source model). This source model produces a final image, which takes into account a pixelated field of view, a realistic conversion between physical flux and counts per second, the convolution with the expected point spread function, a sky background and noise fluctuations. The current version of the simulator is available at the Glendama website, and it allows users to specify all relevant parameters of each point-like or extended source, drag-and-drop sources by using a mouse or a fingertip/stylus on a touchscreen, change the frame size or the brightness scale, etc.     

Microlensing variability in FBQ 0951+2635: short-time-scale events or a long-time-scale fluctuation?

We present and analyse new R -band frames of the gravitationally lensed double quasar FBQ 0951+2635. These images were obtained with the 1.5-m AZT-22 Telescope at Maidanak (Uzbekistan) during the 2001–2006 period. Previous results in the R band (1999–2001 period) and the new data allow us to discuss the dominant kind of microlensing variability in FBQ 0951+2635. The time evolution of the flux ratio A / B does not favour the continuous production of short-time-scale (∼months) flares in the faintest quasar component B (crossing the central region of the lensing galaxy). Instead of a rapid variability scenario, the observations are consistent with the existence of a long-time-scale fluctuation. The flux ratio shows a bump during the 2003–2004 period and a quasi-flat trend in more recent epochs. Apart from the global behaviour of A / B , we study the intra-year variability over the first semester of 2004, which is reasonably well sampled. Short-time-scale microlensing is not detected in that period. Additional data in the i band (from new i -band images taken in 2007 with the 2-m Liverpool Robotic Telescope at La Palma, Canary Islands) also indicate the absence of short-time-scale events in 2007.     

Analysis of the Difference Light Curve of the Gravitational Mirage QSO 0957+561

From optical data of Q0957+561 for 1995/1996 seasons (in the g band) and 1996/1997 seasons (in the R band) they are derived upper limits on the amplitude of the rapid microlensing fluctuations of 0.07 mag and 0.05 mag, respectively. The photometry in the R band (1996/1997 seasons) was taken at Teide Observatory (IAC-80 Telescope), Instituto de Astrofisica de Canarias, Spain. In this contribution, we also study the microlensing history (from 1981 to 1996) of the Twin QSO, which is a curious system with two optical images of similar brightness. This revised version was published online in July 2006 with corrections to the Cover Date.     

Far-infrared Detection of C3 in Sagittarius B2 and IRC +10216

We report on the detection of nine lines of the nu2 bending mode of triatomic carbon, C3, in the direction of Sagittarius B2. The R(4) and R(2) lines of C3 have been also detected in the carbon-rich star IRC +10216. The abundances of C3 in the direction of Sgr B2 and IRC +10216 are approximately 3x10-8 and approximately 10-6, respectively. In Sgr B2 we have also detected the 23-12 line of NH with an abundance of a few times 10-9. Polyatomic molecules will have a weak contribution from their pure rotational spectrum to the emission/absorption in the far-infrared. We suggest, however, that they could be, through their low-lying vibrational bending modes, the dominant carriers of emission/absorption in the spectrum of bright far-infrared sources.