Tracing jet--ISM interaction in young AGN: correlations between [OIII] 5007 and 5-GHz emission

*AIMS: To study the interaction between young AGN and their host galaxies based on their ionized gas and radio emission, and to analyze possible implications for the radio galaxy evolution. *METHODS: The [OIII] 5007 line and 5-GHz radio properties are compared and studied on a large, representative sample of GPS and CSS (i.e., young) quasars and radio galaxies as well as large-scale sources using [OIII] 5007 line and 5-GHz radio data from literature and our observations. *RESULTS: Several correlations between the [OIII] 5007 line and 5-GHz radio emission have been found. The main result is that the [OIII] 5007 emission is strongly related to the GPS/CSS source size indicating that the [OIII] 5007 emission is clearly enhanced by the jet expansion through the host galaxy ISM. Shocks are the most likely enhancing mechanism, although jet-induced star formation could also be, partly, responsible for the [OIII] 5007 emission. The data also suggests a possible deceleration of the jet as it grows. In this case, however, the correlation is weak.Comment: Accepted by A&

AGN Jet-induced Feedback in Galaxies. II. Galaxy colours from a multicloud simulation

We study the feedback from an AGN on stellar formation within its host galaxy, mainly using one high resolution numerical simulation of the jet propagation within the interstellar medium of an early-type galaxy. In particular, we show that in a realistic simulation where the jet propagates into a two-phase ISM, star formation can initially be slightly enhanced and then, on timescales of few million years, rapidly quenched, as a consequence both of the high temperatures attained and of the reduction of cloud mass (mainly due to Kelvin-Helmholtz instabilities). We then introduce a model of (prevalently) {\em negative} AGN feedback, where an exponentially declining star formation is quenched, on a very short time scale, at a time t_AGN, due to AGN feedback. Using the Bruzual & Charlot (2003) population synthesis model and our star formation history, we predict galaxy colours from this model and match them to a sample of nearby early-type galaxies showing signs of recent episodes of star formation (Kaviraj et al. 2007). We find that the quantity t_gal - t_AGN, where t_gal is the galaxy age, is an excellent indicator of the presence of feedback processes, and peaks significantly around t_gal - t_AGN \approx 0.85 Gyr for our sample, consistent with feedback from recent energy injection by AGNs in relatively bright (M_{B} \lsim -19) and massive nearby early-type galaxies. Galaxies that have experienced this recent feedback show an enhancement of 3 magnitudes in NUV(GALEX)-g, with respect to the unperturbed, no-feedback evolution. Hence they can be easily identified in large combined near UV-optical surveys.Comment: 18 pages, 16 figures, accepted for publication on MNRAS. This version includes revisions after the referee's repor

Radial structure, inflow and central mass of stationary radiative galaxy clusters

We analyse the radial structure of self-gravitating spheres consisting of multiple interpenetrating fluids, such as the X-ray emitting gas and the dark halo of a galaxy cluster. In these dipolytropic models, the adiabatic dark matter sits in equilibrium, while the gas develops a gradual, smooth, quasi-stationary cooling flow. Both affect and respond to the collective gravitational field. We find that all subsonic, radially continuous, steady solutions require a non-zero minimum central point mass. For Mpc-sized haloes with 7–10 effective degrees of freedom (F2), the minimum central mass is compatible with observations of supermassive black holes. Smaller gas mass influxes enable smaller central masses for wider ranges of F2. The halo comprises a sharp spike around the central mass, embedded within a core of nearly constant density (at 101–102.5 kpc scales), with outskirts that attenuate and naturally truncate at finite radius (several Mpc). The gas density resembles a broken power law in radius, but the temperature dips and peaks within the dark core. A finite minimum temperature occurs due to gravitational self-warming, without cold mass dropout nor needing regulatory heating. X-ray emission from the intracluster medium mimics a β-model plus bright compact nucleus. Near-sonic points in the gas flow are bottlenecks to the allowed steady solutions; the outermost are at kpc scales. These sites may preferentially develop cold mass dropout during strong perturbations off equilibrium. Within the sonic point, the profile of gas specific entropy is flatter than s∝r1/2, but this is a shallow ramp and not an isentropic core. When F2 is large, the inner halo spike is only marginally Jeans stable in the central parsec, suggesting that a large non-linear disturbance could trigger local dark collapse on to the central object

The X-ray luminous cluster underlying the bright radio-quiet quasar H1821+643

We present a Chandra observation of the only low redshift, z=0.299, galaxy cluster to contain a highly luminous radio-quiet quasar, H1821+643. By simulating the quasar PSF, we subtract the quasar contribution from the cluster core and determine the physical properties of the cluster gas down to 3 arcsec (15 kpc) from the point source. The temperature of the cluster gas decreases from 9.0\pm0.5 keV down to 1.3\pm0.2 keV in the centre, with a short central radiative cooling time of 1.0\pm0.1 Gyr, typical of a strong cool-core cluster. The X-ray morphology in the central 100 kpc shows extended spurs of emission from the core, a small radio cavity and a weak shock or cold front forming a semi-circular edge at 15 arcsec radius. The quasar bolometric luminosity was estimated to be 2 x 10^{47} erg per sec, requiring a mass accretion rate of 40 Msolar per yr, which corresponds to half the Eddington accretion rate. We explore possible accretion mechanisms for this object and determine that Bondi accretion, when boosted by Compton cooling of the accretion material, could provide a significant source of the fuel for this outburst. We consider H1821+643 in the context of a unified AGN accretion model and, by comparing H1821+643 with a sample of galaxy clusters, we show that the quasar has not significantly affected the large-scale cluster gas properties.Comment: 20 pages, 19 figures, accepted by MNRA

Relationship between the [OIII] 5007 line and 5GHz radio emission

I have compiled observations of [OIII] 5007 line and 5GHz radio emission for a large sample of GPS, CSS and FR sources. Several properties were studied and compared. The most relevant findings are that the FWHM and the luminosity of the [OIII] 5007 line are correlated with the size of the radio source. I present the data and discuss the correlations, with special focus on jet-host interaction, triggering and enhancing of [OIII] 5007 emission.Comment: To appear in the proceedings of the 4th GPS and CSS workshop (Astronomische Nachrichten 2009

Evidence for powerful AGN winds at high redshift: Dynamics of galactic outflows in radio galaxies during the "Quasar Era"

AGN feedback now appears as an attractive mechanism to resolve some of the outstanding problems with the "standard" cosmological models, in particular those related to massive galaxies. To directly constrain how this may influence the formation of massive galaxies near the peak in the redshift distribution of powerful quasars, z~2, we present an analysis of the emission-line kinematics of 3 powerful radio galaxies at z~2-3 (HzRGs) based on rest-frame optical integral-field spectroscopy obtained with SINFONI on the VLT. HzRGs are among the most massive galaxies, so AGN feedback may have a particularly clear signature. We find evidence for bipolar outflows in all HzRGs, with kinetic energies that are equivalent to 0.2% of the rest-mass of the supermassive black hole. Velocity offsets in the outflows are ~800-1000 km s^-1 between the blueshifted and redshifted line emission, FWHMs ~1000 km s^-1 suggest strong turbulence. Ionized gas masses estimated from the Ha luminosity are of order 10^10 M_s, similar to the molecular gas content of HzRGs, underlining that these outflows may indicate a significant phase in the evolution of the host galaxy. The total energy release of ~10^60 erg during a dynamical time of ~10^7 yrs corresponds to about the binding energy of a massive galaxy. Geometry, timescales and energy injection rates of order 10% of the kinetic energy flux of the jet suggest that the outflows are most likely driven by the radio source. The global energy density release of ~10^57 erg s^-1 Mpc^-3 may also influence the subsequent evolution of the HzRG by enhancing the entropy and pressure in the surrounding halo and facilitating ram-pressure stripping of gas in satellite galaxies that may contribute to the subsequent mass assembly of the HzRG through low-dissipation "dry" mergers.Comment: A&A in press, minor edits & typo in table captions 2-

Essential Role of Gab1 for Signaling by the C-Met Receptor in Vivo

The docking protein Gab1 binds phosphorylated c-Met receptor tyrosine kinase directly and mediates signals of c-Met in cell culture. Gab1 is phosphorylated by c-Met and by other receptor and nonreceptor tyrosine kinases. Here, we report the functional analysis of Gab1 by targeted mutagenesis in the mouse, and compare the phenotypes of the Gab1 and c-Met mutations. Gab1 is essential for several steps in development: migration of myogenic precursor cells into the limb anlage is impaired in Gab1−/− embryos. As a consequence, extensor muscle groups of the forelimbs are virtually absent, and the flexor muscles reach less far. Fewer hindlimb muscles exist, which are smaller and disorganized. Muscles in the diaphragm, which also originate from migratory precursors, are missing. Moreover, Gab1−/− embryos die in a broad time window between E13.5 and E18.5, and display reduced liver size and placental defects. The labyrinth layer, but not the spongiotrophoblast layer, of the placenta is severely reduced, resulting in impaired communication between maternal and fetal circulation. Thus, extensive similarities between the phenotypes of c-Met and HGF/SF mutant mice exist, and the muscle migration phenotype is even more pronounced in Gab1−/−:c-Met+/− embryos. This is genetic evidence that Gab1 is essential for c-Met signaling in vivo. Analogy exists to signal transmission by insulin receptors, which require IRS1 and IRS2 as specific docking proteins

Ultraluminous Starbursts from SMBH-induced outflows

I argue that there are two modes of global star formation. Disks and smaller spheroids form stars relatively inefficiently as a consequence of supernova-triggered negative feedback via a sequence of ministarbursts (S mode), whereas massive spheroids formed rapidly with high efficiency via the impact of AGN jet-triggered positive feedback (J mode) that generates and enhances ultraluminous starbursts. Supermassive black hole growth by accretion is favoured in the gas-rich protospheroid environment as mergers build up the mass of the host galaxy and provide a centrally concentrated gas supply. Quasi-spherical outflows arise and provide the source of porosity as the energetic jets from the accreting central SMBH are isotropised by the inhomogeneous interstellar medium in the protospheroid core. Super-Eddington outflows occur and help generate both the SMBH at high redshift and the strong positive feedback on protospheroid star formation that occurs as dense interstellar clouds are overpressured and collapse. SMBH form before the bulk of spheroid stars, and the correlation between spheroid velocity dispersion and supermassive black hole mass arises as AGN-triggered outflows limit the gas reservoir for spheroid star formation. The super-Eddington phase plausibly triggers a top-heavy IMF in the region of influence of the SMBH. The Compton-cooled Eddington-limited outflow phase results in a spheroid core whose phase space density scales as the inverse 5/2 power of the core mass, and whose mass scales as the 3/2 power of SMBH mass. This latter scaling suggests that SMBH growth (and hence spheroid formation) is anti-hierarchical.Comment: 6 pages. References added, minor corrections, to match published version, MNRAS in pres

Life History of Female Preferences for Male Faces: A Comparison of Pubescent Girls, Nonpregnant and Pregnant Young Women, and Middle-aged Women

Although scientific interest in facial attractiveness has developed substantially in recent years, few studies have contributed to our understanding of the ontogeny of facial preferences. In this study, attractiveness of 30 male faces was evaluated by four female groups: girls at puberty, nonpregnant and pregnant young women, and middle-aged women. The main findings are as follows: (1) Preference for sexy-looking faces was strongest in young, nonpregnant women. (2) Biologically more mature girls displayed more adultlike preferences. (3) The intragroup consistency for postmenopausal women was relatively low. (4) In terms of the preference pattern, pregnant women were more similar to perimenopausal women than they were to their nonpregnant peers. (5) Preference for youthful appearance decreased with the age of the women. I argue that the life history of female preferences for male faces is, to a large extent, hormone-driven and underpinned by a set of evolutionary adaptations

Using the Fundamental Plane of Black Hole Activity to Distinguish X-ray Processes from Weakly Accreting Black Holes

The fundamental plane of black hole activity is a relation between X-ray luminosity, radio luminosity, and black hole mass for hard state Galactic black holes and their supermassive analogs. The fundamental plane suggests that, at low-accretion rates, the physical processes regulating the conversion of an accretion flow into radiative energy could be universal across the entire black hole mass scale. However, there is still a need to further refine the fundamental plane in order to better discern the radiative processes and their geometry very close to the black hole, in particular the source of hard X-rays. Further refinement is necessary because error bars on the best-fit slopes of the fundamental plane are generally large, and also the inferred coefficients can be sensitive to the adopted sample of black holes. In this work, we regress the fundamental plane with a Bayesian technique. Our approach shows that sub-Eddington black holes emit X-ray emission that is predominantly optically thin synchrotron radiation from the jet, provided that their radio spectra are flat or inverted. X-ray emission dominated by very radiatively inefficient accretion flows are excluded at the >3\sigma\ level. We also show that it is difficult to place FR I galaxies onto the fundamental plane because their X-ray jet emission is highly affected by synchrotron cooling. On the other hand, BL Lac objects fit onto the fundamental plane. Including a uniform subset of high-energy peaked BL Lac objects from the SDSS, we find sub-Eddington black holes with flat/inverted radio spectra follow log L_x=(1.45\pm0.04)log L_R-(0.88\pm0.06)\logM_{BH}-6.07\pm1.10, with \sigma_{int}=0.07\pm0.05 dex. Finally, we discuss how the effects of synchrotron cooling of jet emission from the highest black hole masses can bias fundamental plane regressions, perhaps leading to incorrect inferences on X-ray radiation mechanisms.Comment: 23 pages, 8 figures, 3 tables. Accepted for publication in MNRA