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Background continuum, and short integrations with the Very Large Array (VLA) provide sensitivities of order 1 mJy in a 20 km s-1 channel. Therefore, the VLA is rapidly sensitive to NH 3 x 1021 cm-2. Gallimore et al. 15 reported a systematic imaging survey of 21 cm absorption in Seyfert galaxies. The surprising result was that 21 cm absorption generally failed to detect absorption that could be uniquely identified with a compact, parsec-scale torus. The material was commonly detected at...

L n3 ln 4 kV hv kT

For heavier ions more complicated forms must be used, and since the heavier ions contribute disproportionately to the X-ray output (because of the Zj2 factor), the calculation of the correct Gaunt factor becomes a computational issue. In SI units, (14) becomes Ev 6.8 x 10-51 Z2T-1 2(ne m-3) (nj m-3) gff e-hv kT W m-3 Hz-1 At temperatures below 2 keV, line radiation cannot be ignored, and the plasma models incorporated into X-ray spectral-fitting programs such as...

The Impact of AGN on their Environments 41 Outflows and Winds

In this section I review some of the mechanisms by which AGN are observed to transfer energy to their immediate environment. The potential importance of the black hole can be readily illustrated when one considers the total energy generated by a quasar over its lifetime. If we assume growth by accretion to a total mass M with the usual efficiency j ( 0.1), folding in the typical black-hole bulge mass ratio of 0.1 , the energy released by the quasar is therefore 10-4Mbulgec2. If we compare this...

Main Components of AGN

The AGN phenomenon, while defined as being in the nuclear region, can cover a large range of radii and hence a large range of physical conditions. The physical properties of any gas component are determined by its location (which determine the gravity and the ionizing flux), density (that gives the ionization parameter) and column density (specifies the optical depth and hence the effective radiation pressure force and the self-gravity). Other important factors are the local pressure...

Mh 10 MKk 654

If one assumes that a correlates with the circular speed Vc which bears an intimate relation to the DM halo within the standard CDM paradigm. A plethora of theoretical studies have explored the growth of BHs and the possible origin of a fundamental Mbh-a relation (e.g., Haehnelt & Kauff-mann 2000 Adams, Graff, & Richstone 2001 Burkert & Silk 2001 Di Mat-teo, Croft, Springel, & Hernquist 2003 Bromm & Loeb 2003 Wyithe & Loeb 2003 El-Zant et al. 2003). According to Haehnelt &...

Disk Winds

There is increasing evidence for the existence of disk winds in AGNs, e.g., 6, 10, 19 . Disk winds are observed in both Galactic binaries and in young stellar objects, and may be a feature common to accretion disks on all scales. There has been much theoretical investigation in this area, but it is not clear whether AGN disk winds ought to be driven radiatively or hydromagnetically, or perhaps by some hybrid. It may well be that what we think of as the BLR is itself a composite. Photoionization...

Optical luminosity XLx 5100A

Measured time delays for H0 versus optical luminosity for over 30 reverberation-mapped AGNs, including multiple measurements of some sources. The relationship between BLR size and luminosity can be fitted with r(H0) a Lo.e o.i. Based on data from 25 In Fig. 6, we plot the size of the broad H -emitting region as a function of the optical luminosity at 5100 A for over 30 AGNs, some represented by multiple measurements at different epochs. The observed slope of this correlation, t(H ) x...

Jet Composition

Much of the detailed physics of jets depends on what they contain. While it is clear from their polarized radiation that jets contain fast charged particles and magnetic fields, it is less clear whether these are primary energy-carrying constituents of the jet or secondary. A number of different possibilities for the energy carriers have been suggested. The most popular are that the jets are primarily composed of electrons and positrons, or of electrons and protons, although electromagnetic...

Nho NhONhO

Therefore, dust is more efficient in attenuating the ionizing radiation in highly ionized gas, where it absorbs a larger fraction of the photons capable of ionizing hydrogen. The different ionization structures of dusty and dust-free environments are illustrated in Figs. 7 and 8. Because of its large cross section, dust is also subjected to large radiation pressure force which is then delivered to the gas through the efficient charge coupling of the two components. In fact, the radiation...

Free Free Absorption

The molecular clouds in a parsec-scale torus will be exposed to intense ionizing radiation. The result is an abundance of free electrons in the ionized skin and warm atomic layer that can absorb centimeter-wave radiation by the inverse bremsstrahlung process, which, in astronomy, is more commonly referred to as free-free absorption. The general expression for free-free opacity is fairly complicated but can be simplified at specific wavebands by applying a suitable approximation for the Gaunt...

Isodelay Surfaces

As noted above, the velocity-delay map represents the response of the BLR to a -function outburst, as seen by a distant observer. At the moment the observer detects the outburst, he will also detect the response of the emissionline gas along his line of sight to the continuum source the total path followed by the ionizing photons that leave the central source and are replaced by emission-line photons when they encounter the BLR gas is the same path followed by the unabsorbed photons that are...

Mb 01 Mo y T5Jr

Table 1 shows typical observed bolometric luminosities and inferred mass accretion rates for QSOs and local AGN (Seyfert, LINERS) assuming a standard radiative efficiency e 0.1. The standard value of e 0.1 applies if the gravitational binding energy liberated by the accreting gas at the last stable orbit of the BH is radiated with an efficiency of 0.1 c2. In practice, the radiative efficiency depends on the nature of the accretion disk and gas accretion flows. For instance, thin-disk accretion...