An evolving view of the BLR

Emissions Like That Horse

The consensus view of AGN structure has remained fairly stable, if somewhat vague and lacking in details and self-consistency, for over 15 years. During that period, work has steadily progressed, and there have been some long-standing issues on which consensus is beginning to emerge. The following constitutes the author's personal view of some of the changes that are beginning to take hold. The notion that the BLR is comprised of a large number of discrete gas clouds can be traced back to the...

Francesca Matteucci

Basic assumptions and equations of chemical evolution To build galaxy chemical-evolution models one needs to elucidate a number of hypotheses and make assumptions on the basic ingredients. Initial conditions whether the mass of gas out of which stars will form is all present initially or will be accreted later on the chemical composition of the initial gas (primordial or already enriched by a pregalactic stellar generation). is the star-formation (SF) rate (SFR) and Stellar evolution and...

Info

Doppler Tomography Astronomy

Optical spectra of dMe stars. Reproduced from Mochnacki et al. (2002). 7.4.4 Galactic compact-object sources of emission lines As the final section of this work, we turn to Galactic compact-object systems as sources of emission lines. These include cataclysmic variables (CVs) as well as X-ray binaries -both neutron-star and black-hole binaries. Cataclysmic variables (CVs) are accretion-powered binary systems with a white dwarf as the compact object. This general...

The theory of reverberation mapping

Because of the small angular size of central regions of even the nearest AGNs, the structure and kinematics of the BLR remain a mystery. Fundamentally, the problem is that the line profiles and line-flux ratios are insufficient to constrain what is certainly a complex region indeed, the line profiles are highly degenerate and tell us virtually nothing about the BLR kinematics. Moreover, we have already seen that, whereas photoionization-equilibrium modeling can give us some insight into the...

Participants

Ag ero, M Atek, Hakim Barro Calvo, Guillermo Barway, S dhansh Casebeer, Darrin A. Colavitti, Edoardo Cottis, Christopher Delgado Inglada, Gloria Diaz Santos, Tanio Fernandez Lorenzo, Miriam Gonz lez Perez, Violeta Hayes, Matthew Hernandez Fernandez, Jonathan David Hurley, Rossa Ilic, Dragana Izquierdo G mez, Jaime K hler, Ralf KovaCeviC, Jelena Koziel, Dorota K sterer, Daniel-Jens Lara Lopez, Maritza Lazarova, Mariana Lee, Janice Paz Universidad de C rdoba (Argentina) Institute d'Astrophysique...

Questions pending

There are a few important aspects that have not been mentioned above, for the sake of a more-linear presentation. Most of them have been treated extensively in Stasinnska (2004), and will be mentioned here only briefly, with some updates if necessary. 1.5.1 Correction for reddening, undderlying stellar absorption and aperture effects Before being analysed in terms of abundances or star-formation rates or being compared with the results of photoionization models, the intensities of observed...

Redshift wavelength

A schematic representation of a star-forming galaxy situated beyond the reionization redshift (here indicated at zr 6.5), its surrounding cosmological HII region, the neutral IGM down to zr and the transparent (ionized) IGM towards observer. Redshift and observed Lya wavelength increase to the right. galactic Lya profile plus a reduction of the Lya flux if neutral H is present close in velocity redshift space to the source. The first is well known observationally as the Lya forest,...

Lya physics and astrophysics

Since Lya, one of the strongest emission lines in the UV, plays an important role in searches for and studies of distant and primeval galaxies, we wish to discuss this line, the basic principles governing it, its diagnostics and possible difficulties, empirical findings etc. To the best of my knowledge few if any reviews or lectures summarizing these topics in a single text exist. 4.3.1 ISM emission and escape All ionized regions, i.e. HII regions, the diffuse ISM and like regions in galaxies,...

References

Abel, N. et al. 2003, PASP, 115, 188 Aller, L. H. 1984, Physics of Thermal Gaseous Nebulae (Dordrecht Kluwer) Alloin, D., Collin-Souffrin, S., Joly, M., Vigroux, L. 1979, A& A 78, 200 Bahcall, J. N., Steinhardt, C. L., Schlegel, D. 2004, ApJ, 600, 520 Baldwin, J., Phillips, M. M., Terlevich, R. 1981, PASP, 93, 5 Bautista, M. A. 2006, IAUS, 234, 203 Beckman, J. E., Zurita, A., Rozas, M., Cardwell, A., Relano, M. 2002, RMxAC, 12, 213 Binette, L., Luridiana, V., Henney, W. J. 2001, RMxAC, 10,...

The discovery and nature of active galaxies

The word activity in connection with phenomena in the nuclei of galaxies appears to have originated with Ambartsumian (1968). An ADS search on the specific phrase active galactic nuclei reveals that it was first used in the title of a paper by Weedman (1974) in an invited presentation at a meeting of the American Astronomical Society and first used in a Ph.D. dissertation title by Eilek (1975, 1977). Initially, activity in galactic nuclei referred primarily to radio emission, although it was...

[Inobservable Region 912UV Red IR

An illustration of the dangers of judging massive stars by their optical IR spectral properties. Reproduced from Conti (1986). Figure 7.23. An illustration of the dangers of judging massive stars by their optical IR spectral properties. Reproduced from Conti (1986). deaths are also prime contributors to the chemical enrichment of galaxies as a function of age. The most-massive stars are also notoriously unstable objects. Their high temperatures combined with significant outflows...

The dark ages

3.2.1 Cosmological preliminaries Recent CMB experiments, in conjunction with new measurements of the large-scale structure in the present-day Universe, the SN Ia Hubble diagram, and other observations, have led to a substantial reduction in the uncertainties in the parameters describing the ACDM concordance cosmology. We appear to be living in a flat + a 1) universe dominated by a cosmological constant and seeded with an approximately scale-invariant primordial spectrum of Gaussian density...

G Aviv

Where kx is the telescope-plus-detector efficiency at A, Fc is the continuum flux in the line filter, Tl is the transmission of the line filter, 1 is the line flux, and Avc and Avl are the bandwidths of the continuum filter and the line filter, respectively. Figure 8.6. An image of the spectrophotometric standard star BD1747. The star is marked Figure 8.6. An image of the spectrophotometric standard star BD1747. The star is marked The number of counts per second of the calibration star is and...

Tudo Sobre Astronomers 2ook At The Firt Stars

The variance of the matter-density field versus mass M, for several different cosmologies, all based on WMAP results. Solid curve 3-year-WMAP-only best-fit model. Dotted curve AWDM with a particle mass mX 2 keV, otherwise the same as before. Dashed curve 3-year-WMAP best-fit running spectral index model. Dash-dotted curve 1-year-WMAP-only best-fit tilted model. Here n refers to the spectral index at k 0.05 Mpc-1. The horizontal line at the top of the figure shows the value of the...

Longslit spectroscopy

Flying Spot Scanner

MIGUEL SANCHEZ-PORTAL AND ANA P REZ-GARC A Spectroscopy is the main tool for studying the physics of astrophysical objects. Spec-troscopic observations can be thought to be a method by which one samples the emitted spectral energy distribution SED from an astronomical source in wavelength bins of size AA. For example, narrow-band-filter photometry is a very-low-resolution spectroscopy technique. The required spectral resolution, i.e. the ability to separate the different spectral features lines...