The observed properties of supermassive black holes suggest a fundamental link between their assembly and the formation of their host spheroids. We model the growth and activity of black holes in galaxies using ΛCDM cosmological hydrodynamic simulations. We study the evolution of the metal enrichment in quasar hosts and hence explore the relationship between star/spheroid formation and black hole growth/activity in galaxies. Using the simulations we approach the epoch of the first quasars and the first significant star formation activity. We show that the hosts of the rare bright quasars at z∼5−6 have star formation rates of several hundred $\rm\thinspace M_{\odot}\yr^{-1},$ and halo masses of order ∼1012$\rm\thinspace M_{\odot}$. Already at these redshifts they have supersolar ($Z/Z_{\odot} \sim 2-3$) central metallicities, with a mild dependence of metallicity on luminosity, consistent with observed trends.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Our view of galaxy evolution has been dramatically enhanced by recent deep field surveys at far-infrared and submillimeter wavelengths. Current evidence suggests that the number density of the most luminous far-infrared sources evolves strongly with redshift, and that the luminosity density in the far-infrared/submillimeter may exceed that in the optical/ultraviolet by factors of 3−10 at redshifts z > 1. If true, then as much as 80-90% of the “activity” in galaxies at z > 1 may be hidden by dust. Surveys of complete samples of luminous infrared galaxies in the local Universe show that the majority, if not all objects with log $(L_{\rm ir}/L_\odot) \simgt 11.6$, appear to be major mergers of molecular gas-rich disks accompanied by dust-enshrouded nuclear starbursts and powerful AGN. If the majority of the deep-field sources are simply more distant analogs of local luminous infrared galaxies, then we may be witnessing at z ∼1−3 the primary epoch in the formation of spheroids and massive black holes. This major event in galaxy evolution is largely missed by current deep optical/ultraviolet surveys.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We discuss obbservations and numerical simulations which show that radiative shocks in jet-cloud collisions can trigger the collapse of intergalactic clouds and subsequent star formation in low luminosity, ‘FR-I’ type, radio galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We discuss some recent results from a program to study the relationships between AGNs, super-massive black holes (SMBHs), and their surrounding host galaxies. The results are based on broad emission-line diagnostics of the SMBH masses and metal abundances in a unique sample of 578 Type 1 AGNs.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The formation and growth of supermassive black holes (SMBHs) physically linked with bulges are considered. We focus on the radiation hydrodynamic process for the growth of SMBH in the optically thick starburst phase, where radiation from bulge stars drives the mass accretion on to a galactic center through radiation drag effect. In the present scenario, the AGN luminosity-dominant phase (QSO phase) is preceded by the host luminosity-dominat phase, which is called “proto-QSO phase”. In this phase, there exists the massive dusty disks within younger bulges. Also, the proto-QSO phase is anticipated by an optically-thick ultraluminous infrared galaxy (ULIRG) phase. Furthermore, such radiation hydrodynamic model has been also applied to disk galaxies. It turns out that the mass of a SMBH primarily correlates with a bulge component even in a disk galaxy. Thus, by analogy to proto-QSOs, the BH growing phase in disk galaxies may have massive dusty disks within younger bulges.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present near-infrared imaging of the host galaxies of 17 quasars at 1 < z < 2, obtained with ISAAC at the ESO VLT UT1 under excellent seeing (∼0.4 arcsec). The radio-loud (RLQ) and radio-quiet (RQQ) quasars in the sample have similar distribution of redshift and optical luminosity. Both RLQ and RQQ hosts follow the cosmic evolution of massive inactive ellipticals undergoing passive evolution. This indicates that nuclear activity can occur in all luminous ellipticals without producing a significant change in their global properties and evolution. However, there is a systematic difference by a factor ∼2 in the host luminosity between RLQs and RQQs, which remains the same from z = 2 to z = 0. Quasar hosts are already well formed at z ∼2, in disagreement with hierarchical models of AGN and galaxy formation and evolution models. No correlation is found between the nuclear and the host luminosities. If the host luminosity is proportional to the black hole mass, as in nearby massive spheroids, both types of quasars emit at very different levels with respect to their Eddington luminosity.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present the black hole mass–bulge velocity dispersion relation for a complete sample of 75 soft X-ray selected AGNs. We find that the AGNs with highest accretion rates relative to Eddington lie below the MBH–σ relation of broad line Seyfert 1s, confirming the Mathur et al. (2001) result. The statistical result is robust and not due to any systematic measurement error. This has important consequences towards our understanding of black hole formation and growth: black holes grow by accretion in well formed bulges. As they grow, they get closer to the MBH–σ relation for normal galaxies. The accretion is highest in the beginning and dwindles as time goes by. Our result does not support theories of the MBH–σ relation in which the black hole mass is a constant fraction of the bulge mass/velocity dispersion at all times or those in which bulge growth is controlled by AGN feedback.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

In this work I present the survey which is searching for the rise in the volume-averaged star formation rate at intermediate redshifts (z<1). This survey is a combination of the data taken with Advanced Camera for Surveys in parallel with WFPC2 (U band) of the GOODS fields. We use template fitting of the spectral energy distributions to obtain photometric redshifts and classify the objects as starbursts, early- and late-types. The colors of the starbursts were reproduced and ages were estimated with the stellar evolutionary synthesis code Starburst99. By matching the optical catalog with the Chandra X-ray catalog we have identified the X-ray sources and possible candidates for having a combination of active nuclei and starburst at intermediate redshifts. Analysis of the light concentration, asymmetry and clumpiness, shows that this sample is a mixed bag, containing dwarf ellipticals, early and late-spirals and peculiar objects which resemble mergers in progress. These results have strong implications for galaxy evolution since it shows for the first time who are the candidates for the rise of the SFR at intermediate-z.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present HST/STIS FUV images of the Lyα and FUV continuum emission of the luminous emission line nebulae in the cooling core cluster A1795. The Lyα and FUV continuum emission consist of a diffuse component (∼60%) and more compact features (knots and filaments) which lie preferentially along the radio source edges. The correlations between the FUV continuum flux and the Lyα emission line flux implies that the nebulae are mainly ionized locally. We suggest that the FUV knots are star clusters with ongoing star formation with rates of several solar masses per year. It appears that star formation occurs through out the nebula, though it is strongly enhanced along the edges of the radio source. The radio source may play a key role in the ionization and morphology of the nebula, e.g., by snow-plowing the gas, shocking and ionizing the gas, triggering star formation, and destroying clouds that it has engulfed. The observed FUV continuum is consistent with about half the number of hot stars which are required to ionize the nebula. We note that we may be missing some of the FUV flux due to obscuration. Thus, we find that young hot stars (e.g., O5) probably provide the bulk of the photons which ionize the nebula, though other sources of ionization may contribute in selected regions of the nebula. We suggest that the mass accretion rates are comparable to the star formation rates (of order 10 M[odot ] yr−1). This is consistent with the lack of intermediate temperature gas (<1 keV) being due to energy input to the cooling gas, rather than to “hiding” the cooling gas.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Recent detection of a large optical depth to Thomson scattering by Wilkinson Microwave Anisotropy Probe (WMAP) implicates in new considerations about reionization epoch. Nowadays it is possible to simulate hydrogen reionization for redshift 15 < z < 20, although the greater difficult problem consists to know what are the first ionizing sources in the universe. Observations on Gunn-Peterson effect reconciled with WMAP findings suggests z ∼6 as the redshift for complete reionization. Study on the formation history of supermassive black holes (SMBHs) in galaxies suggests an interplay among QSOs activity and star rate formation. On this aspect, QSOs work as clocks of star formation in spheroids. Observations of magnesium abundance in QSOs for various redshifts show that star formation in these systems began very early.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We discuss the discovery of six bright Lyman break galaxy candidates in the Sloan Digital Sky Survey and the follow-up observations necessary to determine whether they are powered by star formation or by active galactic nuclei.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We analyzed spectra of 15 luminous high-redshift quasars (3.3<z<5.1) and we derived black hole masses that are based on Hβ, MgII, and CIV emission lines, in the range of $2\times10^8<M_{bh}<4\times10^{10} M_\odot$. Assuming exponential growth of the black holes we estimated that it takes about several 100 Myr up to 1 Gyr to accumulate the observed black hole masses, i.e., most of the SMBHs that power these quasars at high-redshifts, started to grow at $z \simeq 5 {\rm to} 10$.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present a physical and numerical model of accretion driven growth of super-massive black holes. In this model we can account for (a) the existence of $> 10^9 \textrm{M}_\odot$ black holes already in the first quasars and (b) for the observation that the lower luminosity AGN distribution peaks later in the evolution of the Universe than that of more luminous objects.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Deep, high-resolution I-band images of 24 BL Lac objects between z = 0.3 and 1.3 taken with the NOT and the ESO-NTT and VLT telescopes are discussed. In 17/24 (71%) of the BL Lac objects, we detected an underlying nebulosity, in 11/17 the host of the BL Lac in the redshift range z = 0.3-1 (< z > = 0.6). The host galaxies are luminous (MI = −25.2±0.8) and large (re = 10.5±7 kpc). They are on average about 0.6 mag brighter than BL Lac host galaxies at z ∼ 0.3 indicative of evolution, whereas their half-light radii are similar. By combining our data with literature data at low-redshift and applying evolutionary models to them, we find that the properties of the host galaxies of BL Lac objects up to z ∼ 1 are compatible with passively evolving elliptical galaxies formed at a redshift of z ≥ 2. Host galaxies of low-luminosity radio-loud AGN (BL Lac/FR I) have very similar properties to the hosts of radio-quiet QSOs and high-luminosity radio-loud AGN (radio-loud QSO/FR II) over a wide redshift range. This supports the picture of the “Grand Unification”, in which AGN activity is a transient phenomenon in galaxy evolution.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

J and K-band imaging with Gemini N has resolved the host galaxies of QSOs of redshifts 4.7 to 5.2. We also discuss I and Z band imaging of two QSOs of redshift above 6.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We analyze the properties of quasar variability using repeated SDSS imaging data in five UV-to-far red photometric bands, accurate to 0.02 mag, for ∼13,000 spectroscopically confirmed quasars. The observed time lags span the range from 3 hours to over 3 years, and constrain the quasar variability for rest-frame time lags of up to two years, and at rest-frame wavelengths from 1000Å to 6000Å. We demonstrate that ∼66,000 SDSS measurements of magnitude differences can be described within the measurement noise by a simple function of only three free parameters. The addition of POSS data constrains the long-term behavior of quasar variability and provides evidence for a turn-over in the structure function. This turn-over indicates that the characteristic time scale for optical variability of quasars is of the order 1 year.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Near-infrared and optical imaging of BL Lac host galaxies is used to investigate their colour properties. We find that the R–H colour and colour gradient distributions of the BL Lac hosts are much wider than those for normal ellipticals, and many objects have very blue hosts and/or steep colour gradients. The blue colours are most likely caused by recent star formation. The lack of obvious signs of interaction may, however, require a significant time delay between the interaction event with associated star formation episodes and the onset of the nuclear activity.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

From a long-term study of IR mergers/QSOs (at low redshift), we report detailed spectroscopic evidences for outflow (OF)and starburst features. We found extreme velocity OF (EVOF) in IRAS 01003-2238, 11119+3257, 13218+0552, 14394+5332, 15130-1958 and 15462-0450. The EVOF were detected mainly in objects with strong starburst plus obscured IR QSOs. Meanwhile, the low velocity OF components were detected in objects with starburst and LINER processes. HST images of IR+BAL+Fe II QSOs show in practically all of these objects “arc or shell” features probably associated to galactic-winds. In addition, results from a study of two-dimensional (2D) fibre spectroscopy of IR mergers/QSOs with galactic winds are presented. Comparing our data base for IR mergers/QSOs with two sample of nearby mergers we found in both samples a high proportion (75 per cent) of IR mergers with galactic winds.

From a very deep imaging and spectroscopic survey of Lyα emitters (LAEs) at z=5.7 we present the results of a study of sample of 20 LAEs candidates. Two of these objects have been already confirmed as LAE at z = 5.7. We detected in one of these LAE (at z=5.687), spectral features probably associated with the more distant galactic wind observed to date.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We describe MUSYC, a 1 square degree multiwavelength survey that will make unique contributions in several areas and is particularly well suited for the study of high redshift AGN.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We summarize the detection rates at wavelengths other than optical for ∼99,000 galaxies from the Sloan Digital Sky Survey (SDSS) Data Release 1 “main” spectroscopic sample. The analysis is based on positional cross-correlation with source catalogs from ROSAT, 2MASS, IRAS, GB6, FIRST, NVSS and WENSS surveys. We find that the rest-frame UV-IR broad-band galaxy SEDs form a remarkably uniform, nearly one parameter, family. As an example, the SDSS u and r band data, supplemented with redshift, can be used to predict K band magnitudes measured by 2MASS with an rms scatter of only 0.2 mag; when measurement uncertainties are taken into account, the astrophysical scatter appears not larger than ∼0.1 mag.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html