Related papers: A tentative elementary model of quasars
Matter flows in the central regions of quasars during their active phases are probably responsible for the properties of the super-massive black holes and that of the bulges of host galaxies. To understand how this mechanism works, we need…
While complicated, unreliable alternatives to Doppler effect were proposed, an elementary optical light- matter interaction provides one which is commonly observed in the labs, but with a distortion due to the use of short, powerful laser…
We study the optical appearance of a thin accretion disk around a Schwarzschild black hole pierced by a cosmic string with a semi-analytic method of Luminet [11]. Direct and secondary images with different parameters observed by a distant…
In the context of AGN unification scheme rapid variability properties play an important role in understanding any intrinsic differences between sources in different classes. In this respect any clue based on spectral properties will be very…
The unification model for powerful radio galaxies and radio-loud quasars postulates that these objects are intrinsically the same but viewed along different angles. Herschel Space Observatory data permit the assessment of that model in the…
The tidal disruption of a star by a supermassive black hole provides us with a rare glimpse of these otherwise dormant beasts. It has long been predicted that the disruption will be accompanied by a thermal `flare', powered by the accretion…
We have conducted a NIR study of the environments of seven radio-loud quasars at redshifts 1<z<1.6. In present paper we describe deep $K$ band images obtained for the fields of ~6X6 arcmin around the quasars with 3$\sigma$ limiting…
We present an extensive X-ray spectral analysis of the cores of 19 FRII sources in the redshift range 0.5<z<1.0 which were selected to be matched in isotropic radio power. The sample consists of 10 radio galaxies and 9 quasars. We compare…
Ultra-violet (UV) radiation from accreting black holes ionizes the intergalactic gas around early quasars, carving out highly ionized bubbles in their surroundings. Any changes in a quasar's luminosity are therefore predicted to produce…
We performed a new analysis of B and R light curves of a sample of PG quasars. We confirm the variability-redshift correlation and its explanation in terms of spectral variability, coupled with the increase of rest-frame observing frequency…
It is known since 1968 that the interaction of a pulse of light with matter redshifts the spectrum; the theory is clarified, to obtain the conditions for which, with incoherent light, one gets a redshift similar to a Doppler shift rather…
In a single optical spectrum, the quasar narrow-line region (NLR) reveals low density, photoionized gas in the host galaxy interstellar medium, while the immediate vicinity of the central engine generates the accretion disk continuum and…
This paper proposes a simple, empirically derived, unifying structure for the inner regions of quasars. This structure is constructed to explain the broad absorption line (BAL) regions, the narrow `associated' ultraviolet and X-ray warm…
The first short part of this review is a general, but very detailed, critique of the literature advocating a class of Seyfert galaxies intrinsically lacking broad emission lines. My conclusion is that there is little or no evidence for such…
Low-frequency radio surveys are ideal for selecting orientation-independent samples of extragalactic sources because the sample members are selected by virtue of their isotropic steep-spectrum extended emission. We use the new 7C Redshift…
The rapid and seemingly random fluctuations in X-ray luminosity of Seyfert galaxies provided early support for the standard model in which Seyferts are powered by a supermassive black hole fed from an accretion disc. However, since EXOSAT…
A star that passes too close to a massive black hole will be torn apart by tidal forces. The flare of photons emitted during the accretion of the stellar debris is predicted to be observable and candidates of such events have been observed…
The reliable theory of the evolution of heavy stars predicts the existence of a type of neutron stars which accrete a cloud of dirty hydrogen (accretors). Although they are very small (some hundreds of kilometres), the accretors should be…
The continuum morphologies of high redshift radio galaxies and quasars can be modeled as enormous bipolar reflection nebulae from shells of dust swept up by bipolar outflows. If the observed shape of a particular object is fit with an…
The "Impulsive Stimulated Raman Scattering" (ISRS), is generally performed using ultrashort laser pulses. It shifts the frequency of the laser beam without any change of the wave surfaces and any appearance of extra lines. ISRS works with…