Note: This page contains sample records for the topic complex broad line from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

The Complex Broad Absorption Line Profiles in a Sample of QSO Spectra  

NASA Astrophysics Data System (ADS)

Most of the Broad Absorption Lines (BALs) in quasars show very complex profiles. An idea to explain these profiles is that the dynamical systems of broad line regions are not homogeneous but consist of a number of dense regions or ion populations with different physical parameters. This approach is used to study the ultraviolet C IV resonance lines in the spectra of a group of high ionization BAL quasars, using the Gauss-Rotation model.

Lyratzi, E.; Danezis, E.; Popovi?, L. ?.; Antoniou, A.; Dimitrijevi?, M. S.; Stathopoulos, D.

2011-08-01

2

Unveiling the broad band X-ray continuum and iron line complex in Mrk 841  

NASA Astrophysics Data System (ADS)

Context: Mrk 841 is a bright Seyfert 1 galaxy known to harbor a strong soft excess and a variable K? iron line. Historical UV, X and ?-rays observations show clear variation of its spectrum in flux and in shape on a monthly time scale. Aims: Mrk 841 has been observed during 3 different periods (January 2001, January 2005 and July 2005) by XMM-Newton for a total cumulated exposure time of ~108 ks. We present in this paper a broad band spectral analysis of the complete EPIC-pn data sets. These are the best observations so far for the study of the soft excess and iron line complex in this source. Methods: We use different methods of data analysis including model-independent methods (spectral ratios, rms, ...) as well as model fitting. We were able to test two different models for the soft excess, a relativistically blurred photoionized reflection (REF model) and a relativistically smeared ionized absorption (ABS model). The continuum is modeled by a simple cut-off power law and we also add a neutral reflection. Results: These observations confirm the presence of a soft excess and iron line and reveal extreme and puzzling spectral and temporal behaviors. The 0.5-3 keV soft X-ray flux decreases by a factor 3 between 2001 and 2005 and the line shape appears to be a mixture of broad and narrow components, the former being variable on small (ks) time scale while the later is consistent with being constant. The 2-10 keV spectrum also hardens between 2001 and 2005. We succeed in describing this complex broad-band 0.5-10 keV spectral variability using either REF or ABS to fit the soft excess. Both models give statistically equivalent results even including simultaneous BeppoSAX data up to 200 keV. Both models are consistent with the presence of remote reflection characterized by a constant narrow component in the data. However they differ in the presence of a broad line component present in REF but not needed in ABS. Consequently the physical interpretation of the line profile variability is quite different, resulting from the variability of the broad line component in REF and from the variability of the absorbing medium in ABS. This study also reveals the sporadic presence of relativistically redshifted narrow iron lines, one of them being detected at 4.8 keV in the EPIC-pn instruments at more than 98.5% confidence level. If interpreted as the blue horn of a relativistically distorted neutral iron line, the large redshift implies the presence of a Kerr black hole.

Petrucci, P. O.; Ponti, G.; Matt, G.; Longinotti, A. L.; Malzac, J.; Mouchet, M.; Boisson, C.; Maraschi, L.; Nandra, K.; Ferrando, P.

2007-08-01

3

Erasing a false dichotomy: The complex nature of broad absorption line quasars  

NASA Astrophysics Data System (ADS)

The main goal of this thesis is to test the various models proposed to explain the important subclass of quasars known as broad absorption line (BAL) quasars. In particular, I focus on whether viewing angle alone can explain why only a fraction of quasars exhibit BALs in their optical/ultraviolet spectra, or if some other model or combination of models is more likely. Much of the work contained here focuses on radio-selected BAL quasars, a relatively poorly studied class to this point, and so a secondary goal is to provide a detailed analysis of their properties. Finally, I provide a large spectropolarimetric atlas of BAL quasars for use by the community. Using new multi-frequency radio observations of a large sample of BAL quasars, and a carefully selected, well-matched sample of unabsorbed quasars, I show that there does appear to be an overabundance of steep-spectrum BAL sources, though they cover a wide range of spectral slopes. Monte-Carlo modeling of these distributions show that BAL quasars are seen from a range of viewing angles, including all of the viewing angles that unabsorbed quasars are seen from. However, at the largest viewing angles, we will generally see BAL quasars. No other spectral features or quasar outflow properties correlate with viewing angle, suggesting that BAL winds in all directions are driven by the same mechanism. BAL quasars are indeed more likely to be polarized than non-BAL sources. However, this is not simply due to orientation or extinction of the direct un-polarized continuum light, as polarization does not correlate with viewing angle or dust extinction. It seems that there is much variation in the polarizing scattering material, both in its location and geometry, between individual sources. This makes it difficult to use polarization studies to constrain BAL quasar models, though it is likely useful for detailed study of individual objects. Simple explanations using only one parameter are clearly no longer sufficient, and we must move toward a more complex picture to explain these objects.

DiPompeo, Michael A.

4

INVESTIGATING THE COMPLEX X-RAY SPECTRUM OF A BROAD-LINE 2MASS RED QUASAR: XMM-NEWTON OBSERVATION OF FTM 0830+3759  

SciTech Connect

We report results from a 50 ks XMM-Newton observation of the dust-reddened broad-line quasar FTM 0830+3759 (z = 0.413) selected from the Faint Images of the Radio Sky at Twenty cm/Two Micron All Sky Survey red quasar survey. For this active galactic nucleus (AGN), a very short 9 ks Chandra exposure had suggested a feature-rich X-ray spectrum and Hubble Space Telescope images revealed a very disturbed host galaxy morphology. Contrary to classical, optically selected quasars, the X-ray properties of red (i.e., with J - K{sub s} > 1.7 and R - K{sub s} > 4.0) broad-line quasars are still quite unexplored, although there is a growing consensus that, due to moderate obscuration, these objects can offer a unique view of spectral components typically swamped by the AGN light in normal, blue quasars. The XMM-Newton observation discussed here has definitely confirmed the complexity of the X-ray spectrum revealing the presence of a cold (or mildly ionized) absorber with N{sub H} {approx} 10{sup 22} cm{sup -2} along the line of sight to the nucleus and a Compton reflection component accompanied by an intense Fe Kalpha emission line in this quasar with a L{sub 2-10{sub keV}} {approx} 5 x 10{sup 44} erg s{sup -1}. A soft-excess component is also required by the data. The match between the column density derived by our spectral analysis and that expected on the basis of reddening due to the dust suggests the possibility that both absorptions occur in the same medium. FTM 0830+3759 is characterized by an extinction/absorption-corrected X-ray-to-optical flux ratio alpha{sub ox} = -2.3, which is steeper than expected on the basis of its UV luminosity. These findings indicate that the X-ray properties of FTM 0830+3759 differ from those typically observed for optically selected broad-line quasars with comparable hard X-ray luminosity.

Piconcelli, Enrico; Nicastro, Fabrizio; Fiore, Fabrizio [Osservatorio Astronomico di Roma (INAF), Via Frascati 33, I-00040 Monte Porzio Catone, Italy. (Italy); Vignali, Cristian [Dipartimento di Astronomia, Universita di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Bianchi, Stefano [Dipartimento di Fisica, Universita degli Studi Roma Tre, via della Vasca Navale 84, I-00146 Roma (Italy); Miniutti, Giovanni, E-mail: piconcelli@oa-roma.inaf.i [LAEX, Centro de Astrobiologia (CSIC-INTA) LAEFF, P.O. Box 78, E-28691 Villanueva de la Canada, Madrid (Spain)

2010-02-20

5

The Polarization of Broad Absorption Line QSOS  

NASA Astrophysics Data System (ADS)

We present the combined results of optical polarization surveys of QSOs showing broad absorption lines (BALQSOs) conducted at the Steward and McDonald Observatories. The merged list of 53 objects provides the first statistical justification for claims of the tendency of BALQSOs to show stronger than average polarization, with a typical BALQSO being polarized a factor 2.4 times greater than a QSO from an optical survey selected without regard for absorption lines. Spectropolarimetry of sufficient quality to distinguish the polarization of emission lines versus absorption troughs versus continuum is also presented for six objects from the survey. When taken together with published data on other sources, the results lead to several significant correlations that can be used to gain insight into the structure of a BALQSO. These include: (1) a reduced degree of polarization in the broad emission lines, (2) enhanced polarization in the absorption troughs, and (3) an increase in the degree of polarization toward shorter wavelengths. In addition, BALQSOs with more prominent absorption systems tend to be more strongly polarized, and there is evidence that the subclass of low-ionization absorbers is more strongly polarized than other BALQSOs. If the increased polarization of BALQSOs is due to attenuation of direct, as opposed to scattered, lines of sight to the nucleus, absorption-line objects are underrepresented in optical surveys, and their true incidence is 20%-30% that of all UV-bright QSOs. Nevertheless, BALQSOs on average are not as highly polarized as their more obscured radio-quiet cousins, the IRAS QSOs/hyperluminous IR galaxies. We are led to a consistent picture in which broad absorption is observed in BALQSOs because they are inclined at intermediate inclinations, where our line of sight passes through gas clouds located near the surface of a dusty torus.

Schmidt, Gary D.; Hines, Dean C.

1999-02-01

6

Variability in Quasar Broad Absorption Line Outflows  

NASA Astrophysics Data System (ADS)

Broad absorption lines (BALs) in quasar spectra identify high velocity outflows that likely exist in all quasars and could play a major role in feedback to galaxy evolution. Studying the variability in these BALs can help us understand the structure, evolution, and basic physical properties of these outflows. We are conducting a BAL monitoring program, which so far includes 163 spectra of 24 luminous quasars, covering time-scales from ˜1 week to 8 years in the quasar rest-frame. We investigate changes in both the CIV ?1550 and SiIV ?1400 BALs, and we report here on some of the results from this program.

Capellupo, D. M.; Hamann, F.; Shields, J. C.; Halpern, J.; Hidalgo, P. R.; Barlow, T. A.

2012-08-01

7

The broad iron line in Active Galactic Nuclei: how X-ray polarimetry can distinguish between relativistic reflection and complex absorption  

NASA Astrophysics Data System (ADS)

The interpretation of very broad iron lines in the X-ray spectra of Active Galactic Nuclei (AGN) remains a matter of debate: on the one hand side, it is believed that the line is due to reflection happening very close to the innermost stable circular orbit (ISCO) of the accretion disk. The extended red wing of the line thus originates from gravitational and Doppler shifting and can put important constraints on the black hole spin. On the other hand, the broad iron line has also been explained by absorption processes in an outflow that partially covers the X-ray source. In this interpretation, the broadening of the line is not directly related to any relativistic effects or black hole spin. Here we explore to which extend an X-ray polarization measurement can distinguish between both models. In general, reflection polarizes light while transmission does not. Therefore, we accurately model the X-ray polarization across the iron line band for various absorption and (relativistic) reflection scenarios. We show that the behavior of the polarization degree and position angle as a function of photon energy can indeed be of great help to decide between the two scenarios.

Marin, Frédéric; Karas, Vladimir; Dovciak, Michal; Matt, Giorgio; Goosmann, Rene; Muleri, Fabio; Porquet, Delphine; Grosso, Nicolas

2012-07-01

8

Magnetohydrodynamic stability of broad line region clouds  

NASA Astrophysics Data System (ADS)

Hydrodynamic stability has been a longstanding issue for the cloud model of the broad line region in active galactic nuclei. We argue that the clouds may be gravitationally bound to the supermassive black hole. If true, stabilization by thermal pressure alone becomes even more difficult. We further argue that if magnetic fields are present in such clouds at a level that could affect the stability properties, they need to be strong enough to compete with the radiation pressure on the cloud. This would imply magnetic field values of a few gauss for a sample of active galactic nuclei we draw from the literature. We then investigate the effect of several magnetic configurations on cloud stability in axisymmetric magnetohydrodynamic simulations. For a purely azimuthal magnetic field which provides the dominant pressure support, the cloud first gets compressed by the opposing radiative and gravitational forces. The pressure inside the cloud then increases, and it expands vertically. Kelvin-Helmholtz and column density instabilities lead to a filamentary fragmentation of the cloud. This radiative dispersion continues until the cloud is shredded down to the resolution level. For a helical magnetic field configuration, a much more stable cloud core survives with a stationary density histogram which takes the form of a power law. Our simulated clouds develop sub-Alfvénic internal motions on the level of a few hundred km s-1.

Krause, Martin; Schartmann, Marc; Burkert, Andreas

2012-10-01

9

On the polarization of resonantly scattered emission lines - III. Polarization of quasar broad emission lines and broad absorption line troughs  

Microsoft Academic Search

The contribution to the expected linear polarization of quasar broad emission and absorption lines from resonance scattering is computed using a Monte Carlo approach for specific, generic models. Attention is focused on the external illumination of the scattering region. The polarization of the reflected component from an externally illuminated slab with finite optical depth is first considered as a model

H.-W. Lee; R. D. Blandford

1997-01-01

10

SN 2007bg: the complex circumstellar medium around one of the most radio-luminous broad-lined Type Ic supernovae  

NASA Astrophysics Data System (ADS)

In this paper we present the results of the radio light curve and X-ray observations of broad-lined Type Ic (Ic-BL) SN 2007bg. The light curve shows three distinct phases of spectral and temporal evolution, implying that the supernova (SN) shock likely encountered at least three different circumstellar medium regimes. We interpret this as the progenitor of SN 2007bg having at least two distinct mass-loss episodes (i.e. phases 1 and 3) during its final stages of evolution, yielding a highly stratified circumstellar medium. Modelling the phase 1 light curve as a freely expanding, synchrotron-emitting shell, self-absorbed by its own radiating electrons, requires a progenitor mass-loss rate of skew4dot{M}? 1.9× 10^{-6}(v_w/1000 km s^{-1}) M? yr-1 for the last t ˜ 20(vw/1000 km s-1) yr before explosion and a total energy of the radio-emitting ejecta of E ? 1 × 1048 erg 10 d after explosion. This places SN 2007bg among the most energetic Type Ib/c events. We interpret the second phase as a sparser `gap' region between the two winds stages. Phase 3 shows a second absorption turn-on before rising to a peak luminosity 2.6 times higher than in phase 1. Assuming this luminosity jump is due to a circumstellar medium density enhancement from a faster previous mass-loss episode, we estimate that the phase 3 mass-loss rate could be as high as skew4dot{M}lesssim 4.3× 10^{-4}(v_w/1000 km s^{-1}) M? yr-1. The phase 3 wind would have transitioned directly into the phase 1 wind for a wind speed difference of ?2. In summary, the radio light curve provides robust evidence for dramatic global changes in at least some Ic-BL progenitors just prior (˜10-1000 yr) to explosion. The observed luminosity of this SN is the highest observed for a non-gamma-ray-burst Ic-BL SN, reaching L8.46 GHz ? 1 × 1029 erg Hz-1 s-1, ˜567 d after explosion.

Salas, P.; Bauer, F. E.; Stockdale, C.; Prieto, J. L.

2013-01-01

11

Velocity distribution of quasar/AGN broad emission line clouds  

SciTech Connect

In the present work, the effects of geometric projection are deconvolved from the observed broad emission line profiles from a number of active galaxies to reveal the intrinsic brightness versus velocity function of the emission-line clouds. Results are presented as total emission per absolute velocity interval, rather than imposing specific dynamical models on the data. It is concluded from the analysis that the preponderance of evidence indicates that the broad-line emission arises from gas with preferred absolute velocity relative to line center. 9 references.

Puetter, R.C.; Hubbard, E.N.

1987-09-01

12

Absorption-Line Variability of Broad-Absorption Line Quasars  

NASA Astrophysics Data System (ADS)

We present first results of an ongoing study of BAL QSO variability. Our goal is to infer the amplitude and the timescale of absorption-line variations. While about 75% of our BAL QSOs show no or only minor variations, we discovered the transition of a weak BAL QSO into a strong Lo-BAL QSO, with the MgII ? 2798 emission line and the adjacent FeII UV emission completely vanishing in less than 10 years.

Dietrich, M.; Mathur, S.; Terndrup, D. M.; Hall, P. B.; Leighly, K. M.; Barber, S. D.

2012-08-01

13

Broad Absorption Line Quasar catalogues with Supervised Neural Networks  

NASA Astrophysics Data System (ADS)

We have applied a Learning Vector Quantization (LVQ) algorithm to SDSS DR5 quasar spectra in order to create a large catalogue of broad absorption line quasars (BALQSOs). We first discuss the problems with BALQSO catalogues constructed using the conventional balnicity and/or absorption indices (BI and AI), and then describe the supervised LVQ network we have trained to recognise BALQSOs. The resulting BALQSO catalogue should be substantially more robust and complete than BI-or AI-based ones.

Scaringi, Simone; Cottis, Christopher E.; Knigge, Christian; Goad, Michael R.

2008-12-01

14

The orientation and polarization of broad absorption line quasars  

NASA Astrophysics Data System (ADS)

We present new spectropolarimetric observations of eight radio-loud broad absorption line (BAL) quasars, and combine these new data with our previous spectropolarimetric atlases (of both radio-loud and radio-quiet objects; DiPompeo et al. 2010, DiPompeo et al. 2011a) in order to investigate the polarization properties of BAL quasars as a group. The total (radio-selected) sample includes 36 (26) high-ionization and 22 (15) low-ionization BAL quasars (HiBALs and LoBALs, respectively). On average, we confirm that broad emission lines are polarized at a level similar to or less than the continuum and broad absorption troughs are more highly polarized, but we note that these properties are not true for all individual objects. Of the whole sample, 18 (31 per cent) have high (>2 per cent) continuum polarization, including 45 per cent of the LoBALs and 22 per cent of the HiBALs. We identify a few correlations between polarization and other quasar properties, as well as some interesting non-correlations. In particular, continuum polarization does not correlate with radio spectral index, which suggests that the polarization is not due to a standard geometry and preferred viewing angle to BAL quasars. The polarization also does not correlate with the amount of intrinsic dust reddening, indicating that the polarization is not solely due to direct light attenuation either. Polarization does appear to depend on the minimum BAL outflow velocity, confirming the results of previous studies and it may correlate with the maximum outflow velocity. We also find that continuum polarization anticorrelates with the polarization in the C iv broad emission and broad absorption. These results suggest that the polarization of BAL quasars cannot be described by one simple model, and that the scatterer location and geometry can vary significantly from object to object.

DiPompeo, M. A.; Brotherton, M. S.; De Breuck, C.

2013-01-01

15

A simple disc wind model for broad absorption line quasars  

NASA Astrophysics Data System (ADS)

Approximately 20 per cent of quasi-stellar objects (QSOs) exhibit broad, blue-shifted absorption lines in their ultraviolet spectra. Such features provide clear evidence for significant outflows from these systems, most likely in the form of accretion disc winds. These winds may represent the `quasar' mode of feedback that is often invoked in galaxy formation/evolution models, and they are also key to unification scenarios for active galactic nuclei (AGN) and QSOs. To test these ideas, we construct a simple benchmark model of an equatorial, biconical accretion disc wind in a QSO and use a Monte Carlo ionization/radiative transfer code to calculate the ultraviolet spectra as a function of viewing angle. We find that for plausible outflow parameters, sightlines looking directly into the wind cone do produce broad, blue-shifted absorption features in the transitions typically seen in broad absorption line (BAL) QSOs. However, our benchmark model is intrinsically X-ray weak in order to prevent overionization of the outflow, and the wind does not yet produce collisionally excited line emission at the level observed in non-BAL QSOs. As a first step towards addressing these shortcomings, we discuss the sensitivity of our results to changes in the assumed X-ray luminosity and mass-loss rate, dot{M}_wind. In the context of our adopted geometry, dot{M}_wind ˜ dot{M}_acc is required in order to produce significant BAL features. The kinetic luminosity and momentum carried by such outflows would be sufficient to provide significant feedback.

Higginbottom, N.; Knigge, C.; Long, K. S.; Sim, S. A.; Matthews, J. H.

2013-09-01

16

Keck HIRES Spectra of Three Broad Absorption-Line QSOs  

Microsoft Academic Search

We have observed three broad absorption-line QSOs (BALQSOs) with the Keck HIRES spectrograph with a resolution of 8 km s(-1) and a signal-to-noise of roughly 30-40 per resolution element. We chose three bright, high-redshift QSOs: Q1246-057 (zem=2.22), CSO 755 (1524+517, zem=2.88), and Q1408+567 (zem=2.50). All three QSOs have detached (8,000 to 15,000 km s(-1) outflow) C IV lambda 1549 BALs

T. A. Barlow; V. T. Junkkarinen

1994-01-01

17

The broad-lined Type Ic supernova 2003jd  

NASA Astrophysics Data System (ADS)

The results of a worldwide coordinated observational campaign on the broad-lined Type Ic supernova (SN Ic) 2003jd are presented. In total, 74 photometric data points and 26 spectra were collected using 11 different telescopes. SN 2003jd is one of the most luminous SN Ic ever observed. A comparison with other Type Ic supernovae (SNe Ic) confirms that SN 2003jd represents an intermediate case between broad-line events (2002ap, 2006aj) and highly energetic SNe (1997ef, 1998bw, 2003dh, 2003lw), with an ejected mass of Mej = 3.0 +/- 1Msolar and a kinetic energy of Ek(tot) = 7+3-2 × 1051erg. SN 2003jd is similar to SN 1998bw in terms of overall luminosity, but it is closer to SNe 2006aj and 2002ap in terms of light-curve shape and spectral evolution. The comparison with other SNe Ic suggests that the V-band light curves of SNe Ic can be partially homogenized by introducing a time-stretch factor. Finally, because of the similarity of SN 2003jd to the SN 2006aj/XRF 060218 event, we discuss the possible connection of SN 2003jd with a gamma-ray burst (GRB). E-mail: svalenti@eso.org Based on observations at ESO-Paranal, Prog. 074.D-0161A.

Valenti, S.; Benetti, S.; Cappellaro, E.; Patat, F.; Mazzali, P.; Turatto, M.; Hurley, K.; Maeda, K.; Gal-Yam, A.; Foley, R. J.; Filippenko, A. V.; Pastorello, A.; Challis, P.; Frontera, F.; Harutyunyan, A.; Iye, M.; Kawabata, K.; Kirshner, R. P.; Li, W.; Lipkin, Y. M.; Matheson, T.; Nomoto, K.; Ofek, E. O.; Ohyama, Y.; Pian, E.; Poznanski, D.; Salvo, M.; Sauer, D. N.; Schmidt, B. P.; Soderberg, A.; Zampieri, L.

2008-02-01

18

Spectral decomposition of broad-line agns and host galaxies  

SciTech Connect

Using an eigenspectrum decomposition technique, we separate the host galaxy from the broad line active galactic nucleus (AGN) in a set of 4666 spectra from the Sloan Digital Sky Survey (SDSS), from redshifts near zero up to about 0.75. The decomposition technique uses separate sets of galaxy and quasar eigenspectra to efficiently and reliably separate the AGN and host spectroscopic components. The technique accurately reproduces the host galaxy spectrum, its contributing fraction, and its classification. We show how the accuracy of the decomposition depends upon S/N, host galaxy fraction, and the galaxy class. Based on the eigencoefficients, the sample of SDSS broad-line AGN host galaxies spans a wide range of spectral types, but the distribution differs significantly from inactive galaxies. In particular, post-starburst activity appears to be much more common among AGN host galaxies. The luminosities of the hosts are much higher than expected for normal early-type galaxies, and their colors become increasingly bluer than early-type galaxies with increasing host luminosity. Most of the AGNs with detected hosts are emitting at between 1% and 10% of their estimated Eddington luminosities, but the sensitivity of the technique usually does not extend to the Eddington limit. There are mild correlations among the AGN and host galaxy eigencoefficients, possibly indicating a link between recent star formation and the onset of AGN activity. The catalog of spectral reconstruction parameters is available as an electronic table.

Vanden Berk, Daniel E.; Shen, Jiajian; /Penn State U., Astron. Astrophys.; Yip, Ching-Wa; /Pittsburgh U.; Schneider, Donald P.; /Penn State U., Astron. Astrophys.; Connolly, Andrew J.; /Pittsburgh U.; Burton, Ross E.; /Pittsburgh U. /Case Western Reserve U.; Jester, Sebastian; /Fermilab; Hall, Patrick B.; /York U., Canada; Szalay, Alex S.; /Johns Hopkins U.; Brinkmann, John; /Apache Point Observ.

2005-09-01

19

Phenomenology of Broad Emission Lines in Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

Broad emission lines hold fundamental clues about the kinematics and structure of the central regions in AGN. In this article we review the most robust line profile properties and correlations emerging from the best data available. We identify fundamental differences between the profiles of radio-quiet and radio-loud sources as well as differences between the high- and low-ionization lines, especially in the radio-quiet majority of AGN. An Eigenvector 1 correlation space involving FWHM H?, W(FeIIopt)/W(H?), and the soft X-ray spectral index provides optimal discrimination between all principal AGN types (from narrow-line Seyfert 1 to radio galaxies). Both optical and radio continuum luminosities appear to be uncorrelated with the E1 parameters. We identify two populations of radio-quiet AGN: Population A sources (with FWHM(H?) <~ 4000 km s-1, generally strong FeII emission and a soft X-ray excess) show almost no parameter space overlap with radio-loud sources. Population B shows optical properties largely indistinguishable from radio-loud sources, including usually weak FeII emission, FWHM(H?) >~ 4000 km s-1 and lack of a soft X-ray excess. There is growing evidence that a fundamental parameter underlying Eigenvector 1 may be the luminosity-to-mass ratio of the active nucleus (L/M), with source orientation playing a concomitant role.

Sulentic, J. W.; Marziani, P.; Dultzin-Hacyan, D.

20

Radio characteristics of Broad Absorption Lines (BAL) quasars  

NASA Astrophysics Data System (ADS)

Broad absorption lines (BALs), seen in a small fraction of both the radio-quiet and radio-loud quasar populations, are probably caused by the outflow of gas with high velocities and are part of the accretion process. The presence of BALs is the geometrical effect and/or it is connected with the quasar evolution. It has been believed that BALQSO occurs only among radio-quiet galaxies. However, in 2000 Becker et al. discovered the representative sample of radio-loud objects which exhibits broad absorption troughs. The radio morphologies of radio-loud BAL quasars provide important additional information about their orientation and the direction of the outflow. Using the final release of FIRST survey combined with a A Catalog of BAL QSOs (SDSS/DR3), we have constructed a new sample of compact radio-loud BAL QSOs, which makes the majority of radio-loud BAL QSOs. The main goal of this project is to study the origin of BALs by analysis the BAL QSOs radio morphology, their orientation and jets evolution, using EVN at 1.6 GHz and VLBA at 5 and 8.4 GHz.

Ceglowski, Maciej

2011-07-01

21

Near infrared hydrogen emission line ratios as diagnostics of the broad emission line region  

NASA Astrophysics Data System (ADS)

Broad emission line flux ratios are a powerful diagnostic of the physical conditions of the broad-line region gas in Active Galactic Nuclei. With recent advances in infrared spectroscopy, previously unstudied emission lines provide a new means to investigate the physical nature of the BELR gas. The hydrogen emission lines are particularly sensitive to the upper limits of both the radius from the central ionising source and the number density of the gas. Using an existing subset of near-infrared quasar spectra from the Glikman et al. (2006) sample [1] together with Cloudy photoionization simulations, we confirm the Locally Optimally emitting Cloud (LOC) model's ability to reproduce observed emission line flux ratios. The model is then used to constrain physical conditions for individual sources. The photoionization models show that high number density, low incident flux gas is required to reproduce observed near-infrared hydrogen emission line ratios. We also find that comparison to individual sources, rather than composites, is vital.

Ruff, Andrea J.; Floyd, David J. E.; Korista, Kirk T.; Webster, Rachel L.; Porter, Ryan L.; Ferland, Gary J.

2012-07-01

22

SPECTROSCOPY OF BROAD-LINE BLAZARS FROM 1LAC  

SciTech Connect

We report on optical spectroscopy of 165 flat spectrum radio quasars (FSRQs) in the Fermi 1LAC sample, which have helped allow a nearly complete study of this population. Fermi FSRQs show significant evidence for non-thermal emission even in the optical; the degree depends on the {gamma}-ray hardness. They also have smaller virial estimates of hole mass than the optical quasar sample. This appears to be largely due to a preferred (axial) view of the {gamma}-ray FSRQ and non-isotropic (H/R {approx} 0.4) distribution of broad-line velocities. Even after correction for this bias, the Fermi FSRQs show higher mean Eddington ratios than the optical population. A comparison of optical spectral properties with Owens Valley Radio Observatory radio flare activity shows no strong correlation.

Shaw, Michael S.; Romani, Roger W.; Healey, Stephen E.; Michelson, Peter F. [Department of Physics/KIPAC, Stanford University, Stanford, CA 94305 (United States); Cotter, Garret; Potter, William J. [Department of Astrophysics, University of Oxford, Oxford OX1 3RH (United Kingdom); Readhead, Anthony C. S.; Richards, Joseph L.; Max-Moerbeck, Walter; King, Oliver G. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)

2012-03-20

23

Broad Absorption Line Variability in Radio-Loud Quasars  

NASA Astrophysics Data System (ADS)

We present preliminary results from an investigation into broad absorption line (BAL) variability within a sample of 41 radio-loud quasars (RLQs). Using 28 new Hobby-Eberly Telescope (HET) spectra along with earlier Sloan Digital Sky Survey (SDSS) or other archival data, we generate a total set of 50 pairs of BAL equivalent width measurements. Absorption variability in BAL RLQs typically consists of modest changes in the depth of trough segments, and variability is more common on longer rest-frame timescales; these tendencies are similar to previous findings for BAL radio-quiet quasars (RQQs). BAL variability in RLQs does not show any obvious dependence upon radio luminosity or loudness, but there is suggestive support for greater fractional variability among lobe-dominated RLQs.

Miller, B. P.; Welling, C. A.; Brandt, W. N.; Gibson, R. R.

2012-08-01

24

Variability Constraints on Quasar Broad Absorption Line Outflows  

NASA Astrophysics Data System (ADS)

Broad absorption lines (BALs) in quasar spectra identify high velocity outflows that likely exist in all quasars and could play a major role in feedback to galaxy evolution. Studying the variability in these BALs can help us understand the structure, evolution, and basic physical properties of these outflows. We are conducting a BAL monitoring program, which so far includes 163 spectra of 24 luminous quasars at z=1.2-2.9, covering time-scales from 1 week to 8 years in the quasar rest-frame. We investigate changes in both the CIV BALs and the SiIV BALs, and we see a variety of phenomena, including some BALs with dramatic variability over a wide range in outflow velocities and other BALs that did not change at all over the entire observation period. Variability generally occurred in only portions of BAL troughs. The fraction of quasars with CIV BAL variability increased as we added more observing epochs to our sample, with 88% of the quasars showing CIV BAL variability. When comparing CIV to SiIV BAL variability, we found that SiIV BALs are more likely to vary than CIV BALs. When both the CIV and SiIV BALs vary within the same quasar, they always vary in the same sense (with both lines either getting stronger or weaker). We have new data that probe the shortest time-scales (<1 month rest-frame), which provide constraints on the sizes and location of the outflowing gas. We also present some preliminary results on the study of key diagnostic lines, such as PV ?1118, 1128. Studying these lines provides crucial constraints on the total column densities in the flows, which we can then use to estimate their mass outflow rates and kinetic energy yields. These quantities will help determine the viability of these outflows as a feedback mechanism.

Capellupo, Daniel M.; Hamann, F.; Shields, J. C.; Barlow, T. A.; Halpern, J. P.; Rodriguez Hidalgo, P.

2012-01-01

25

More evidence for the intermediate broad line region of the mapped AGN PG 0052+251  

NASA Astrophysics Data System (ADS)

In this paper, the properties of the proposed intermediate broad emission line region (BLR) are checked for the mapped AGN PG 0052+251. With the considerations of the apparent effects of the broad He II line on the observed broad H? profile, the line parameters (especially the line width and the line flux) of the observed broad H? and the broad H? are carefully determined. Based on the measured line parameters, the model with two broad components applied for each observed broad Balmer line is preferred, and then confirmed by the calculated much different time lags for the inner/intermediate broad components and the corresponding virial black hole mass ratio determined by the properties of the inner and the intermediate broad components. Then, the correlation between the broad line width and the broad line flux is checked for the two broad components: one clearly strong negative correlation for the inner broad component and one positive correlation for the intermediate broad component. The different correlations for the two broad components strongly support the intermediate BLR of PG 0052+251.

Zhang, Xue-Guang

2013-09-01

26

The Energetics of Quasar Broad Absorption Line Outflows  

NASA Astrophysics Data System (ADS)

Broad absorption lines (BALs) in quasar spectra identify high velocity outflows that likely exist in all quasars and could play a major role in feedback to galaxy evolution. In order to determine the viability of these outflows as a feedback mechanism, we need estimates of their mass outflow rates and kinetic energy yields. These quantities depend on the column densities of the flows, which are difficult to obtain directly from spectra of the BALs. To address this problem, we turn to a low-abundance species, PV ?1118, 1128. Phosphorus is much less abundant than, for example, carbon (about 1000 times less abundant in the Sun), so a detection of a PV BAL indicates that other lines, such as the well-studied CIV ?1550 BAL, are saturated. We detect variability in a PV BAL in Q1413+1143, corresponding to variable SiIV ?1400 and CIV BALs. The variability in the PV BAL confirms that the absorption is intrinsic to the quasar and provides a constraint on the location of the gas. Using the apparent optical depth of the PV BAL and photoionization models, we can constrain the true column density of the outflow. With constraints on the location and column density, we estimate the kinetic energy yields and compare to simulations to estimate the viability of the outflow as a feedback mechanism. We also search through archival data to estimate the overall incidence of PV absorption in BAL quasar spectra.

Capellupo, Daniel M.; Hamann, F.; Leighly, K.; Terndrup, D.; Dietrich, M.; Gallagher, S.; Shields, J. C.

2012-05-01

27

Mid-Infrared Spectra of Broad Absorption Line Quasars  

NASA Astrophysics Data System (ADS)

We investigate how broad absorption line quasars (BALQSOs) are related to the normal quasar population using a sample of archival spectra obtained with the infrared spectrograph (IRS) aboard the Spitzer Space Telescope. We find the BALQSO sample has a ~40% larger average 10 micron silicate emission equivalent width and ~40% smaller MIR-to-Optical luminosity ratio than the normal quasar sample. The slopes of the MIR continuum emission in the two populations are identical. We compare these observed results with calculated spectra from the clumpy dusty torus models of Nenkova et al. to determine the implications for the geometry and physical conditions of the circumnuclear dust in the two populations. The observed trends show preference for smaller torus inclination angle and smaller dust covering factor for the BAL sample compared to the normal sample, although a variety of geometric parameters could lead to the observed differences between the two populations. A similar comparison of a sample of lower-luminosity counterparts, Seyfert galaxies with intrinsic absorption, reveals similar but weaker correlations. We interpret these results in the context of the two competing models for the appearance of BALs: orientation versus evolution.

Gabel, Jack; Medvar, B.

2013-01-01

28

The Viewing Angles of Broad Absorption Line versus Unabsorbed Quasars  

NASA Astrophysics Data System (ADS)

It was recently shown that there is a significant difference in the radio spectral index distributions of broad absorption line (BAL) quasars and unabsorbed quasars, with an overabundance of BAL quasars with steeper radio spectra. This result suggests that source orientation does play into the presence or absence of BAL features. In this paper, we provide more quantitative analysis of this result based on Monte Carlo simulations. While the relationship between viewing angle and spectral index does indeed contain a lot of scatter, the spectral index distributions are different enough to overcome that intrinsic variation. Utilizing two different models of the relationship between spectral index and viewing angle, the simulations indicate that the difference in spectral index distributions can be explained by allowing BAL quasar viewing angles to extend about 10° farther from the radio jet axis than non-BAL sources, though both can be seen at small angles. These results show that orientation cannot be the only factor determining whether BAL features are present, but it does play a role.

DiPompeo, M. A.; Brotherton, M. S.; De Breuck, C.

2012-06-01

29

The intrinsic fraction of broad-absorption line quasars  

NASA Astrophysics Data System (ADS)

We carefully reconsider the problem of classifying broad-absorption line quasars (BALQSOs) and derive a new, unbiased estimate of the intrinsic BALQSO fraction from the Sloan Digital Sky Survey (SDSS) DR3 quasi-stellar object (QSO) catalogue. We first show that the distribution of objects selected by the so-called `absorption index' (AI) is clearly bimodal in logAI, with only one mode corresponding to definite BALQSOs. The surprisingly high BALQSO fractions that have recently been inferred from AI-based samples are therefore likely to be overestimated. We then present two new approaches to the classification problem that are designed to be more robust than the AI, but also more complete than the traditional `balnicity index' (BI). Both approaches yield observed BALQSO fractions around 13.5 per cent, while a conservative third approach suggests an upper limit of 18.3 per cent. Finally, we discuss the selection biases that affect our observed BALQSO fraction. After correcting for these biases, we arrive at our final estimate of the intrinsic BALQSO fraction. This is fBALQSO = 0.17 +/- 0.01(stat) +/- 0.03(sys) with an upper limit of fBALQSO ~= 0.23. We conclude by pointing out that the bimodality of the logAI distribution may be evidence that the BAL-forming region has clearly delineated physical boundaries.

Knigge, Christian; Scaringi, Simone; Goad, Michael R.; Cottis, Christopher E.

2008-05-01

30

H? Line Widths as an Orientation Indicator for Low-ionization Broad Absorption Line Quasars  

NASA Astrophysics Data System (ADS)

There is evidence from radio-loud quasars to suggest that the distribution of the H? broad emission line (BEL) gas is arranged in a predominantly planar orientation, and this result may well also apply to radio-quiet quasars. This would imply that the observed FWHM of the H? BELs is dependent on the orientation of the line of sight to the gas. If this view is correct then we propose that the FWHM can be used as a surrogate, in large samples, to determine the line of sight to the H? BELs in broad absorption line quasars (BALQSOs). The existence of broad UV absorption lines (BALs) means that the line of sight to BALQSOs must also pass through the BAL out-flowing gas. It is determined that there is a statistically significant excess of narrow-line profiles in the SDSS DR7 archival spectra of low-ionization broad absorption line quasars (LoBALQSOs), indicating that BAL gas flowing close to the equatorial plane does not commonly occur in these sources. We also find that the data is not well represented by random lines of sight to the BAL gas. Our best fit indicates two classes of LoBALQSOs, the majority (?2/3) are polar outflows that are responsible for the enhanced frequency of narrow-line profiles, and the remainder are equatorial outflows. We further motivated the line of sight explanation of the narrow-line excess in LoBALQSOs by considering the notion that the skewed distribution of line profiles is driven by an elevated Eddington ratio in BALQSOs. We constructed a variety of control samples comprised of non-LoBALQSOs matched to a de-reddened LoBALQSO sample in redshift, luminosity, black hole mass, and Eddington ratio. It is demonstrated that the excess of narrow profiles persists within the LoBALQSO sample relative to each of the control samples with no reduction of the statistical significance. Thus, we eliminate the possibility that the excess narrow lines seen in the LoBALQSOs arise from an enhanced Eddington ratio.

Punsly, Brian; Zhang, Shaohua

2010-12-01

31

WEAK LINE QUASARS AT HIGH REDSHIFT: EXTREMELY HIGH ACCRETION RATES OR ANEMIC BROAD-LINE REGIONS?  

SciTech Connect

We present Gemini-North K-band spectra of two representative members of the class of high-redshift quasars with exceptionally weak rest-frame ultraviolet emission lines (WLQs), SDSS J114153.34+021924.3 at z = 3.55 and SDSS J123743.08+630144.9 at z = 3.49. In both sources, we detect an unusually weak broad H{beta} line and place tight upper limits on the strengths of their [O III] lines. Virial, H{beta}-based black hole mass determinations indicate normalized accretion rates of L/L {sub Edd}=0.4 for these sources, which is well within the range observed for typical quasars with similar luminosities and redshifts. We also present high-quality XMM-Newton imaging spectroscopy of SDSS J114153.34+021924.3 and find a hard-X-ray photon index of {Gamma} = 1.91{sup +0.24} {sub -0.22}, which supports the virial L/L {sub Edd} determination in this source. Our results suggest that the weakness of the broad emission lines in WLQs is not a consequence of an extreme continuum-emission source but instead due to abnormal broad emission line region properties.

Shemmer, Ohad [Department of Physics, University of North Texas, Denton, TX 76203 (United States); Trakhtenbrot, Benny; Netzer, Hagai [School of Physics and Astronomy and the Wise Observatory, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel-Aviv 69978 (Israel); Anderson, Scott F. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Brandt, W. N.; Schneider, Donald P. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Diamond-Stanic, Aleksandar M.; Fan Xiaohui [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Lira, Paulina [Departamento de Astronomia, Universidad de Chile, Camino del Observatorio 1515, Santiago (Chile); Plotkin, Richard M. [Astronomical Institute 'Anton Pannekoek', University of Amsterdam, Science Park 904, 1098 XH, Amsterdam (Netherlands); Richards, Gordon T. [Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Strauss, Michael A., E-mail: ohad@unt.ed [Princeton University Observatory, Peyton Hall, Princeton, NJ 08544 (United States)

2010-10-20

32

Weak Line Quasars at High Redshift: Extremely High Accretion Rates or Anemic Broad-line Regions?  

NASA Astrophysics Data System (ADS)

We present Gemini-North K-band spectra of two representative members of the class of high-redshift quasars with exceptionally weak rest-frame ultraviolet emission lines (WLQs), SDSS J114153.34+021924.3 at z = 3.55 and SDSS J123743.08+630144.9 at z = 3.49. In both sources, we detect an unusually weak broad H? line and place tight upper limits on the strengths of their [O III] lines. Virial, H?-based black hole mass determinations indicate normalized accretion rates of L/L Edd=0.4 for these sources, which is well within the range observed for typical quasars with similar luminosities and redshifts. We also present high-quality XMM-Newton imaging spectroscopy of SDSS J114153.34+021924.3 and find a hard-X-ray photon index of ? = 1.91+0.24 -0.22, which supports the virial L/L Edd determination in this source. Our results suggest that the weakness of the broad emission lines in WLQs is not a consequence of an extreme continuum-emission source but instead due to abnormal broad emission line region properties.

Shemmer, Ohad; Trakhtenbrot, Benny; Anderson, Scott F.; Brandt, W. N.; Diamond-Stanic, Aleksandar M.; Fan, Xiaohui; Lira, Paulina; Netzer, Hagai; Plotkin, Richard M.; Richards, Gordon T.; Schneider, Donald P.; Strauss, Michael A.

2010-10-01

33

Broad K? iron line from accretion disks around traversable wormholes  

NASA Astrophysics Data System (ADS)

It has been proposed that the supermassive black hole candidates at the centers of galaxies might be wormholes formed in the early Universe and connecting our Universe with other sister universes. The analysis of the profile of the relativistic K? iron line is currently the only available approach to probe the spacetime geometry around these objects. In this paper, we compute the expected K? iron line in some wormhole spacetimes and we compare the results with the line produced around Kerr black holes. The line produced in accretion disks around nonrotating or very slow-rotating wormholes is relatively similar to the one expected around Kerr black holes with mid or high value of spin parameter and current observations are still marginally compatible with the possibility that the supermassive black hole candidates in galactic nuclei are these objects. For wormholes with spin parameter a*?0.02, the associated K? iron line is instead quite different from the one produced around Kerr black holes, and their existence may already be excluded.

Bambi, Cosimo

2013-04-01

34

Modeling Line-Driven Disk Wind for Broad Absorption Lines of Quasars  

NASA Astrophysics Data System (ADS)

The disk wind, which is powered by the radiation force due to spectral lines (line force), has been studied concerning broad absorption line (BAL) quasars. We investigated the structure of the disk wind based on a non-hydrodynamic method, and compared it with wind properties inferred from X-ray observations of BAL quasars. In the present work, we applied the stellar wind theory to the initial condition (the mass outflow rate at the base of the wind). We found funnel-shaped winds with a half opening angle of ˜ 50° for the case of ? = 0.3-0.9 and MBH = 107-8.5 M? , where ? is the Eddington ratio and MBH is the black-hole mass. Thus, the absorption features are observed for an observer of which the viewing angle is around 50° . A probability of BAL quasars is ˜ 7%-11%, which is roughly consistent the abundance ratio of BAL quasars, ˜ 10%-15%. Here, the probability is estimated by the solid angle, that the absorbing features would be detected, divided by 4? . In contrast, if the Eddington ratio is smaller than 0.01, or if the black hole is very massive, MBH ? 109 M? , the disk wind is not launched due to the less effective line force. Then, the quasars are identified as non-BAL quasars independently of the observer's viewing angle.

Nomura, Mariko; Ohsuga, Ken; Wada, Keiichi; Susa, Hajime; Misawa, Toru

2013-04-01

35

Variations of broad optical emission lines in AGN  

NASA Astrophysics Data System (ADS)

AGN optical spectra (4000-5000Å) are being observed with the TV scanner of the 6 m telescope at Special Astrophysical Observatory (N. Arkhyz-North Caucasus) since 1986 till now. The usual dispersion is 1Å/channel, the signal-to-noise ratio in individual spectra is S/N = 10-25. NGC 4151, NGC 3516, NGC 5548, and NGC 7469 are the main objects of the programme. Strong variations of H, H, H, and HeII 4686Å line intensities and profile shapes have been observed on a time scale from 10-30 days to several years. The data are being used in international AGN watch programmes for diagnosis, estimation of the size and structure of the BLR.

Bochkarev, N. G.; Shapovalova, A. I.; Nazarova, L. S.

36

An unusual broad line profile in the QSO + 144 - Evidence for an optical jet?  

NASA Astrophysics Data System (ADS)

Narrow components in the profiles of the broad Balmer and Mg II emission lines were observed in the QSO 0054+144 (PHL 909). The redshift given by the narrow permitted lines is smaller than that of the narrow forbidden [O III] lines, by an amount corresponding to a velocity difference of ?1000 km s-1. There was a possible change in both the broad and narrow permitted lines between 1980 and 1986. It is suggested that the narrow Balmer component may have been produced in a short-lived jetlike structure moving outward from the center of the QSO with this relative line-of-sight velocity.

Zheng, Wei; Burbidge, E. Margaret

1988-05-01

37

Probing the time variability of five Fe low broad absorption-line quasars  

NASA Astrophysics Data System (ADS)

We study the time variability of five Fe low-ionization broad absorption line (FeLoBAL) QSOs using repeated spectroscopic observations with the 2-m telescope at IUCAA Girawali Observatory (IGO) spanning an interval of up to 10 years. We report a dramatic variation in the Al III and Fe III fine-structure lines in the spectra of SDSS J221511.93-004549.9 (zem˜ 1.478). However, there is no such strong variability shown by the C IV absorption. This source is known to be unusual with (i) the continuum emission dominated by Fe emission lines, (ii) Fe III absorption being stronger than Fe II and (iii) the apparent ratio of Fe III UV 48 to Fe III UV 34 absorption suggesting an inverted population ratio. This is the first reported detection of time variability in the Fe III fine-structure lines in QSO spectra. There is a strong reduction in the absorption strength of these lines between 2000 and 2008. Using the template-fitting techniques, we show that the apparent inversion of the strength of ultraviolet lines could be related to the complex spectral energy distribution of this QSO. The observed variability can be related to a change in the ionization state of the gas or due to the transverse motion of this absorbing gas. The shortest variability time-scale of Al III line gives a lower limit on the electron density of the absorbing gas as ? cm-3. The remaining four FeLoBALs do not show any changes beyond the measurement uncertainties either in optical depth or in the velocity structure. We present the long-term photometric light curve for all of our sources. Among them only SDSS J221511.93-004549.9 shows significant (?0.2 mag) variability. This paper uses archival data based on observations carried out at the European Southern Observatory (ESO) under programmes 267.B-5698 and 71.B-0121.

Vivek, M.; Srianand, R.; Petitjean, P.; Noterdaeme, P.; Mohan, V.; Mahabal, A.; Kuriakose, V. C.

2012-07-01

38

On the apparent absence of broad iron lines in Seyfert galaxies  

NASA Astrophysics Data System (ADS)

We present an analysis of XMM-Newton observations of 11 Seyfert galaxies that appear to be missing a broad iron K? line. These objects represent a challenge to the established paradigm for active galactic nuclei, where a relatively cold accretion disc feeds the central black hole. In that paradigm, X-ray illumination of the accretion disc should lead to continuum and fluorescence emission from iron which is broadened and shifted by relativistic effects close to the hole. We extend the work of Nandra et al., who found no evidence for such a component in an earlier analysis of these objects, by testing a variety of more complex relativistic reflection models. Specifically, we consider the possibility that the disc is highly ionized, and/or that the reflection is heavily blurred by strong relativistic effects in a Kerr geometry. We find that in 8/11 of the observations with no apparent broad iron line, the fit is significantly improved when an ionized or strongly blurred reflector is included, and that all 11 observations allow for such a component. The disc inclinations are found generally to be around 60°, which when combined with a steep emissivity profile results in strong relativistic blurring of the reflection, rendering the K? line difficult to distinguish from the underlying continuum. Nevertheless, relativistic reflection does appear to be present, and the strength of the smeared reflection is similar to that expected from a flat disc illuminated by a point source. Such blurred reflection and the associated steep radial emissivity profiles are consistent with the gravitational light bending of the continuum photons close to the black hole.

Bhayani, S.; Nandra, K.

2011-09-01

39

Vertical broad-line region structure in nearby active galactic nuclei  

NASA Astrophysics Data System (ADS)

Context. Broad emission lines are emitted in the surroundings of supermassive black holes in the centers of active galactic nuclei (AGN). This region is spatially not resolved. Aims: We intend to get information on the structure and geometry of this broad emitting line region based on line profile observations. Methods: We model the rotational and turbulent velocities in the line-emitting regions based on observed full-width at half maximum line values (FWHM) and ?line of the variable broad emission lines in four nearby AGN: NGC 3783, NGC 7469, NGC 5548, and 3C 390.3. On the basis of these velocities, we estimate the height of the line-emitting regions above the midplane in context with their distances from the center. Results: The H? lines are emitted in a more flattened configuration above the midplane in comparison to the highly ionized lines. The H? lines originate at heights of 0.7 to 1.6 light-days and at distances of 1.4 to 24 light-days with height/distance ratios (H/R) of only 0.07 to 0.5. The highly ionized lines originate at smaller radii than the H? lines and/or at greater distances above the midplane with H/R values of 0.2 to 1.7. In total, the emission lines do not originate in a thin atmosphere of an accretion disk but rather at very extended regions above an accretion disk. The observed geometries of the line-emitting regions resemble the geometries of accretion disk wind models. Furthermore, the angle of the central opening cone (generated by the emitting regions of the highly ionized lines) is small for those galaxies with slow rotational velocities and increases with the rotation velocity of the central region. Conclusions: The derived geometries of the line-emitting regions of all four AGN are consistent with the geometries that are predicted in outflowing disk wind models.

Kollatschny, W.; Zetzl, M.

2013-10-01

40

Why do broad line AGN show up among faint hard X-ray sources?  

NASA Astrophysics Data System (ADS)

We have assembled a sample of ROSAT sources that are harder than the X-ray Background (XRB). By studying a hard X-ray spectrum population we are trying to discover the nature of the as yet unidentified source population needed to resolve the XRB spectral paradox. Current theory would suggest that narrow line QSOs (so called QSO2 objects) should be important, but we find that broad line AGN predominate. Here we discuss the nature of the broad line AGN and show that the absorption responsible for hardening the X-ray spectrum has a variety of optical signatures. .

Mittaz, J. P. D.; Page, M. J.; Carrera, F. J.

2001-12-01

41

A Long-Term Study of Broad Emission Line Profile Variability in NGC 5548: Erratum  

Microsoft Academic Search

In the paper A Long-Term Study of Broad Emission Line Profile Variability in NGC 5548 by Ignaz Wanders and Bradley M. Peterson (ApJ, 466, 174 [1996]), the tabulated emission-line fluxes are too low, as the result of a minor error in one of the computer programs used. All emission-line flux should be multiplied by the integer 2; the continuum fluxes

Ignaz Wanders; Bradley M. Peterson

1997-01-01

42

Broad emission lines from the mass-loss envelopes of giant stars in active galactic nuclei  

SciTech Connect

The source of emission lines with broad range of critical densities emitted from AGNs is investigated. The envelope structure and optical line emissivity of a typical red giant mass-loss envelope is calculated, the emission line profiles are computed for power-law distributions of stars and are compared with the observed line profiles, and the constraints on the orbital motions and stellar distributions, provided by the stellar collision rate, are discussed. The results obtained suggest that the emission lines of active galaxies arise from self-replenishing giant star envelopes during a brief phase (less than 1,000,000 yr) of stellar evolution. 33 references.

Scoville, N.; Norman, C.

1988-09-01

43

The origin of broad emission lines in the extragalactic giant H II region NGC 2363  

Microsoft Academic Search

High signal-to-noise long-slit spectra have been obtained of the giant H II region NGC 2363 located in the dwarf SBm galaxy NGC 2366. A discovery of low-intensity broad spectral components (FWHM is approximately equal to 40 A or 2400 km\\/s) in the bright nebular lines H-alpha, H-beta, and forbidden O III is reported. The broad spectral components are detected over

Jean-Rene Roy; Martin Aube; Marshall L. McCall; R. J. Dufour

1992-01-01

44

Broad Fe K' lines in active galactic nuclei - reflection or absorption? Encouraging constraints from X-ray polarimetry  

NASA Astrophysics Data System (ADS)

A significant number of X-ray bright, type-1 active galactic nuclei show broad Fe K' emission lines. The origin of the broad red wing is attributed to relativistic blurring occurring very close to the innermost stable orbit and thus putting tight constraints on the spin of the black hole. Nonetheless, the broad Fe K' line of the well-studied Seyfert-1 galaxy MCG-6-30-15 has also been modeled by non-relativistic, complex absorption in a wind. Neither spectral nor timing analyzes of present day X-ray data allowed us to distinguish between the two models. In this work, we explore if X-ray polarimetry can resolve the controversy. Using our radiative transfer methods that include the effects of X-ray polarization, we explore a series of absorption and reflection models. It turns out that the polarization spectrum in the 2-10 keV band puts robust constraints on the origin of broad Fe K' lines. We conclude that a long-look observation of MCG-6-30-15 with a small polarimetry satellite could reliably distinguish between the two scenarios.

Marin, Frédéric; Goosmann, René W.; Dov?iak, Michal; Muleri, Fabio; Porquet, Delphine; Grosso, Nicolas; Karas, Vladimir; Matt, Giorgio

2012-09-01

45

Microlensing in H1413+117: disentangling line profile emission and absorption in a broad absorption line quasar  

Microsoft Academic Search

On the basis of 16 years of spectroscopic observations of the four components of the gravitationally lensed broad absorption line (BAL) quasar H1413+117, covering the ultraviolet to visible rest-frame spectral range, we analyze the spectral differences observed in the P Cygni-type line profiles and have used the microlensing effect to derive new clues to the BAL profile formation. We first

D. Hutsemékers; B. Borguet; D. Sluse; P. Riaud; T. Anguita

2010-01-01

46

THE LICK AGN MONITORING PROJECT: ALTERNATE ROUTES TO A BROAD-LINE REGION RADIUS  

SciTech Connect

It is now possible to estimate black hole (BH) masses across cosmic time, using broad emission lines in active galaxies. This technique informs our views of how galaxies and their central BHs coevolve. Unfortunately, there are many outstanding uncertainties associated with these 'virial' mass estimates. One of these comes from using the accretion luminosity to infer a size for the broad-line region (BLR). Incorporating the new sample of low-luminosity active galaxies from our recent monitoring campaign at Lick Observatory, we recalibrate the radius-luminosity relation with tracers of the accretion luminosity other than the optical continuum. We find that the radius of the BLR scales as the square root of the X-ray and H{beta} luminosities, in agreement with recent optical studies. On the other hand, the scaling appears to be marginally steeper with narrow-line luminosities. This is consistent with a previously observed decrease in the ratio of narrow-line to X-ray luminosity with increasing total luminosity. The radius of the BLR correlates most tightly with H{beta} luminosity, while the X-ray and narrow-line relations both have comparable scatter of a factor of 2. These correlations provide useful alternative virial BH masses in objects with no detectable optical/UV continuum emission, such as high-redshift galaxies with broad emission lines, radio-loud objects, or local active galaxies with galaxy-dominated continua.

Greene, Jenny E. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Hood, Carol E.; Barth, Aaron J.; Bentz, Misty C.; Walsh, Jonelle L. [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697-4575 (United States); Bennert, Vardha N.; Treu, Tommaso [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Filippenko, Alexei V. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Gates, Elinor [Lick Observatory, P.O. Box 85, Mount Hamilton, CA 95140 (United States); Malkan, Matthew A. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90024 (United States); Woo, Jong-Hak [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul, Korea, 151-742 (Korea, Republic of)

2010-11-01

47

PG 1700 + 518 - a low-redshift, broad absorption line QSO  

SciTech Connect

The first high-resolution optical spectra and lower resolution UV spectra of PG 1700 + 518, the only known broad-absorption-line (BAL) QSO at low emission redshift (0.288) are presented. The optical data were obtained with the Isaac Newton Telescope on the island of La Palma and the UV data with the International Ultraviolet Explorer satellite. The outstanding feature of the optical spectrum is a strong, broad Mg II absorption trough, detached from the Mg II emission line and indicative of ejection velocities of between 7000 and 18,000 km/s. Also detected were narrow (FWHM = 350 km/s) Mg II absorption lines at absolute z = 0.2698, which are probably related to the mass ejection phenomenon. It is concluded that the emission-line spectrum is similar to that of other low-redshift QSOs although there are some obvious differences from typical BAL QSOs, most notably in the unusually low level of ionization of both emission-line and broad absorption line gas. 21 references.

Pettini, M.; Boksenberg, A.

1985-07-01

48

Polarization of Quasars: Electronic Scattering in the Broad Absorption Line Region  

Microsoft Academic Search

It is widely accepted that the broad absoption line region (BALR) exists in most (if not all) quasars with a small covering factor. Recent works showed that the BALR is optically thick to soft and even medium energy X-rays, with a typical hydrogen column density of a few 1023 to > 1024 cm?2. The electronic scattering in the thick absorber

Hui-Yuan Wang; Ting-Gui Wang; Jun-Xian Wang

49

XMM-Newton Observations of Broad Absorption Line Quasars with Polar Outflows  

NASA Astrophysics Data System (ADS)

We have selected a sample of broad absorption line (BAL) quasars which show significant radio variations, indicating the presence of polar BAL outflows. We obtained snapshot XMM observations of four polar BAL QSOs, to check whether strong X-ray absorption, one of the most prominent characteristics of most BAL QSOs, also exists in polar outflows. Two of the sources are detected in the X-ray. Spectral fittings show that they are X-ray normal with no intrinsic X-ray absorption, suggesting the X-ray shielding gas might be absent in polar BAL outflows. Comparing to non-BAL QSOs, one of two X-ray-nondetected sources remains consistent with X-ray normal, while the other one, which is an iron low-ionization BAL (FeLoBAL), shows an X-ray weakness factor of >19, suggesting strong intrinsic X-ray absorption. Alternative explanations for the nondetection of strong X-ray absorption in the two X-ray-detected sources are that (1) the absorption is more complex than a simple neutral absorber, such as partial covering absorption or ionized absorption; (2) there might be significant jet contribution to the detected X-ray emission. Current data are insufficient to test these possibilities, and further observations are required to understand the X-ray nature of polar BAL outflows.

Wang, Junxian; Jiang, Peng; Zhou, Hongyan; Wang, Tinggui; Dong, Xiaobo; Wang, Huiyuan

2008-04-01

50

Time Variable Broad Line Emission in NGC 4203: Evidence for Stellar Contrails  

NASA Astrophysics Data System (ADS)

Dual epoch spectroscopy of the lenticular galaxy, NGC 4203, obtained with the Hubble Space Telescope has revealed that the double-peaked component of the broad H? emission line is time variable, increasing by a factor of 2.2 in brightness between 1999 and 2010. Modeling the gas distribution responsible for the double-peaked profiles indicates that a ring is a more appropriate description than a disk and most likely represents the contrail of a red supergiant star that is being tidally disrupted at a distance of 1500 AU from the central black hole. There is also a bright core of broad H? line emission that is not time variable and identified with a large scale inflow from an outer radius 1 pc. If the gas number density is ? 106 cm-3, as suggested by the absence of similarly broad [O I] and [O III] emission lines, then the steady state inflow rate is 2 × 10-2 M?/yr which exceeds the inflow requirement to explain the X-ray luminosity in terms of radiatively inefficient accretion by a factor of 6. The central AGN is unable to sustain ionization of the broad line region, the discrepancy is particularly acute in 2010 when the broad H? emission line is dominated by the contrail of the in-falling supergiant star. However, ram pressure shock ionization produced by the interaction of the in-falling supergiant with the ambient interstellar medium may help alleviate the ionizing deficit by generating a mechanical source of ionization supplementing the photoionization provided by the AGN. Support for Program number HST AR-11752.01-A was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, incorporated, under NASA contract NAS5-26555.

Devereux, Nicholas A.

2012-01-01

51

Time Variable Broad-line Emission in NGC 4203: Evidence for Stellar Contrails  

NASA Astrophysics Data System (ADS)

Dual epoch spectroscopy of the lenticular galaxy, NGC 4203, obtained with the Hubble Space Telescope has revealed that the double-peaked component of the broad H? emission line is time variable, increasing by a factor of 2.2 in brightness between 1999 and 2010. Modeling the gas distribution responsible for the double-peaked profiles indicates that a ring is a more appropriate description than a disk and most likely represents the contrail of a red supergiant star that is being tidally disrupted at a distance of ~1500 AU from the central black hole. There is also a bright core of broad H? line emission that is not time variable and identified with a large-scale inflow from an outer radius of ~1 pc. If the gas number density is >=106 cm-3, as suggested by the absence of similarly broad [O I] and [O III] emission lines, then the steady state inflow rate is ~ 2 × 10-2 M ? yr-1, which exceeds the inflow requirement to explain the X-ray luminosity in terms of radiatively inefficient accretion by a factor of ~6. The central active galactic nucleus (AGN) is unable to sustain ionization of the broad-line region; the discrepancy is particularly acute in 2010 when the broad H? emission line is dominated by the contrail of the infalling supergiant star. However, ram pressure shock ionization produced by the interaction of the infalling supergiant with the ambient interstellar medium may help alleviate the ionizing deficit by generating a mechanical source of ionization supplementing the photoionization provided by the AGN.

Devereux, Nick

2011-12-01

52

Complex-type N-glycan recognition by potent broadly neutralizing HIV antibodies.  

PubMed

Broadly neutralizing HIV antibodies (bNAbs) can recognize carbohydrate-dependent epitopes on gp120. In contrast to previously characterized glycan-dependent bNAbs that recognize high-mannose N-glycans, PGT121 binds complex-type N-glycans in glycan microarrays. We isolated the B-cell clone encoding PGT121, which segregates into PGT121-like and 10-1074-like groups distinguished by sequence, binding affinity, carbohydrate recognition, and neutralizing activity. Group 10-1074 exhibits remarkable potency and breadth but no detectable binding to protein-free glycans. Crystal structures of unliganded PGT121, 10-1074, and their likely germ-line precursor reveal that differential carbohydrate recognition maps to a cleft between complementarity determining region (CDR)H2 and CDRH3. This cleft was occupied by a complex-type N-glycan in a "liganded" PGT121 structure. Swapping glycan contact residues between PGT121 and 10-1074 confirmed their importance for neutralization. Although PGT121 binds complex-type N-glycans, PGT121 recognized high-mannose-only HIV envelopes in isolation and on virions. As HIV envelopes exhibit varying proportions of high-mannose- and complex-type N-glycans, these results suggest promiscuous carbohydrate interactions, an advantageous adaptation ensuring neutralization of all viruses within a given strain. PMID:23115339

Mouquet, Hugo; Scharf, Louise; Euler, Zelda; Liu, Yan; Eden, Caroline; Scheid, Johannes F; Halper-Stromberg, Ariel; Gnanapragasam, Priyanthi N P; Spencer, Daniel I R; Seaman, Michael S; Schuitemaker, Hanneke; Feizi, Ten; Nussenzweig, Michel C; Bjorkman, Pamela J

2012-10-30

53

Broad Line Sources on 1000 AU Scales in Sgr B2 Main  

NASA Astrophysics Data System (ADS)

We have recently imaged the Sgr B2 Main region with the Very Large Array in the BnA configuration in both H52? line and 7 mm continuum emission. This study is part of a larger effort to characterize high frequency recombination lines in ultracompact and hypercompact HII regions in the Galaxy. In particular, these observations supplement lower resolution H52? and matched resolution 7 mm continuum observations of the same region. The current observations detect H52? emission in 13 individual sources in Sgr B2 Main. The previous line observations had lower resolution and detected line emission from only 4 sources in the same region. A number of the newly detected sources have broad recombination line emission, and several of the lines may have peaks at more than one velocity. We discuss a number of individual sources in detail and place them in the context of a developing model of the early evolution of ultracompact HII regions.

De Pree, C.; Alexander, E.; Deblasio, J.; Wilner, D.

2004-12-01

54

Weak-Line Quasars at High Redshift: Extremely High Accretion Rates or Anemic Broad-Line Regions?  

NASA Astrophysics Data System (ADS)

We present Gemini-North K-band spectra of two representative members of the class of high-redshift quasars with exceptionally weak rest-frame ultraviolet emission lines (WLQs), SDSS J114153.34+021924.3 at z=3.55 and SDSS J123743.08+630144.9 at z=3.49. In both sources we detect an unusually weak broad H? line and we place tight upper limits on the strengths of their [O III] lines. Virial, H?-based black-hole mass determinations indicate normalized accretion rates of L/LEdd=0.4 for these sources, which is well within the range observed for typical quasars with similar luminosities and redshifts. We also present high-quality XMM-Newton imaging spectroscopy of SDSS J114153.34+021924.3 and find a hard-X-ray photon index of ?=1.91+0.24-0.22which supports the virial L/LEdd determination in this source. Our results suggest that the weakness of the broad-emission lines in WLQs is not a consequence of an extreme continuum-emission source but instead due to abnormal broad-emission line region properties.

Shemmer, Ohad; Trakhtenbrot, B.; Anderson, S. F.; Brandt, W. N.; Diamond-Stanic, A. M.; Fan, X.; Lira, P.; Netzer, H.; Plotkin, R. M.; Richards, G. T.; Schneider, D. P.; Strauss, M. A.

2011-01-01

55

Long-term optical spectral monitoring of Seyfert 1 galaxies: variability in the broad line region  

NASA Astrophysics Data System (ADS)

In spite of many papers devoted to the physical properties (physics and geometry) of the broad line region (BLR) in Seyfert 1 galaxies, the true nature of the BLR is not well known. The BLR is close to the central supermassive black hole (SMBH) and may give information about the mass of the SMBH. The signature of the BLR are the broad emission lines (BEL). Their fluxes, shapes and intensities can provide much information about the BLR geometry and physics. Moreover, Seyfert 1 often exhibit variability in the BEL, that is often assumed to be caused by the dynamic evolution of the BLR gas on long timescales. Therefore, an investigation of the BEL flux and shape variability in a long period is very useful for mapping the geometrical and dynamical structure of the BLR. Here we will present results of the long-term optical spectral monitoring of three Seyfert 1 galaxies with different spectral characteristics: NGC 4151 (with highly variable line-profiles, see Shapovalova et al. 2009, 2010), 3C390.3 (with double-peaked broad lines, see Shapovalova et al. 2010, Popovic et al. 2011), and Ark 564 (a narrow-line Seyfert 1 with strong Fe II emission, Shapovalova et al. 2012). Popovic et al. 2011, A&A, 528, 130 Shapovalova et al. 2008, A&A, 486, 99 Shapovalova et al. 2010, A&A, 517, 42 Shapovalova et al. 2012, A&A, submitted

Popovic, Luka; Chavushian, Vahram; Ilic, Dragana; Kovacevic, Jelena; Shapovalova, Alla I.; Kovacevic, Andjelka; Burenkov, Alexander N.

2012-07-01

56

THE SINS SURVEY: BROAD EMISSION LINES IN HIGH-REDSHIFT STAR-FORMING GALAXIES  

SciTech Connect

High signal-to-noise, representative spectra of star-forming galaxies at z {approx} 2, obtained via stacking, reveal a high-velocity component underneath the narrow H{alpha} and [N II] emission lines. When modeled as a single Gaussian, this broad component has FWHM {approx}> 1500 km s{sup -1}; when modeled as broad wings on the H{alpha} and [N II] features, it has FWHM {approx}> 500 km s{sup -1}. This feature is preferentially found in the more massive and more rapidly star-forming systems, which also tend to be older and larger galaxies. We interpret this emission as evidence of either powerful starburst-driven galactic winds or active supermassive black holes (SMBHs). If galactic winds are responsible for the broad emission, the observed luminosity and velocity of this gas imply mass outflow rates comparable to the star formation rate. On the other hand, if the broad-line regions of active black holes account for the broad feature, the corresponding black holes masses are estimated to be an order of magnitude lower than those predicted by local scaling relations, suggesting a delayed assembly of SMBHs with respect to their host bulges.

Shapiro, Kristen L.; Quataert, Eliot [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Genzel, Reinhard [Department of Physics, University of California, Berkeley, CA 94720 (United States); Foerster Schreiber, Natascha M.; Davies, Richard; Tacconi, Linda; Bouche, Nicolas; Buschkamp, Peter; Cresci, Giovanni; Eisenhauer, Frank; Genel, Shy; Hicks, Erin K. S.; Lutz, Dieter [Max-Planck-Institut fuer extraterrestrische Physik (MPE), Giessenbachstr.1, D-85748 Garching (Germany); Armus, Lee [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Cimatti, Andrea [Istituto Nazionale di Astrofisica-Osservatorio Astronomico di Bologna, Via Gobetti 101, I-40129 Bologna (Italy); Daddi, Emanuele [Service d'Astrophysique, Dapnia CEA, Saclay (France); Erb, Dawn K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Lilly, Simon J. [Institute of Astronomy, Eidgenoessische Technische Hochschule, ETH Zurich CH-8093 (Switzerland); Renzini, Alvio [Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, Padova I-35122 (Italy); Shapley, Alice [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)] (and others)

2009-08-20

57

The view through the wind: X-ray observations of broad absorption line quasi-stellar objects  

Microsoft Academic Search

The 2 10 keV bandpasses and unprecedented sensitivity of modern X-ray observatories have enabled new insights into the immediate environments of Broad Absorption Line (BAL) QSOs. BAL QSOs, approximately 10% of the QSO population, exhibit deep, broad absorption lines from high ionization ultraviolet resonance transitions. These blueshifted absorption features are understood to arise along lines of sight which travel through

Sarah Connoran Gallagher

2002-01-01

58

Broad Iron Lines in Neutrons Stars: Dynamical Broadening or Wind Scattering?  

NASA Astrophysics Data System (ADS)

Broad iron emission lines are observed in many accreting systems from black holes in active galactic nuclei and X-ray binaries to neutron star low-mass X-ray binaries. The origin of the line broadening is often interpreted as due to dynamical broadening and relativistic effects. However, alternative interpretations have been proposed, included broadening due to Compton scattering in a wind or accretion disk atmosphere. Here we explore the observational signatures expected from broadening in a wind, in particular that the iron line width should increase with an increase in the column density of the absorber (due to an increase in the number of scatterings). We study the data from three neutron star low-mass X-ray binaries where both a broad iron emission line and absorption lines are seen simultaneously, and show that there is no significant correlation between line width and column density. This favors an inner disk origin for the line broadening rather than scattering in a wind.

Cackett, Edward M.; Miller, Jon M.

2013-11-01

59

Broad-line region physical conditions along the quasar eigenvector 1 sequence  

NASA Astrophysics Data System (ADS)

We compare broad emission-line profiles and estimate line ratios for all major emission lines between Ly? and H? in a sample of six quasars. The sources were chosen with two criteria in mind: the existence of high-quality optical and ultraviolet spectra and the possibility of sampling the spectroscopic diversity in the 4D eigenvector 1 (4DE1) context. In the latter sense, each source occupies a region (bin) in the full width at half-maximum (FWHM)(H?) versus Fe IIopt strength plane that is significantly different from the others. High signal-to-noise ratio H? emission-line profiles are used as templates for modelling the other lines (Ly?, C IV ?1549, He II ?1640, Al III ?1860, Si III] ?1892 and Mg II ?2800). We can adequately model all broad lines assuming the existence of three components distinguished by blueshifted, unshifted and redshifted centroids [indicated as a blue component (BLUE), broad component (BC) and very broad component (VBC), respectively]. BC (electron density ne˜ 1012 cm-3, ionization parameter U˜ 10-2 and column density Nc? 1023 cm-2) is present in almost all type-1 quasars and therefore corresponds most closely to the classical broad-line emitting region (the reverberating component). The bulk of Mg II ?2800 and Fe II emission also arises in this region. The BLUE emission (log ne˜ 10, log U˜-1 and log Nc < 23) arises in less optically thick gas; it is often thought to arise in an accretion disc wind. The least understood component involves the VBC (high ionization and large column density), which is found in no more than half (but almost all radio-loud) type-1 quasars and luminous Seyfert nuclei. It is perhaps the most distinguishing characteristic of quasars with FWHM (H?) ? 4000 km s-1 that belong to the so-called population B of our 4DE1 space. Population A quasars [FWHM (H?) ? 4000 km s-1] are dominated by BC emission in H? and BLUE component emission in C IV ?1549 and other high ionization lines. 4DE1 appears to be the most useful current context for revealing and unifying spectral diversity in type-1 quasars.

Marziani, P.; Sulentic, J. W.; Negrete, C. A.; Dultzin, D.; Zamfir, S.; Bachev, R.

2010-12-01

60

Subrelativistic Jets from Black Hole Accretion Vortices. II. The Broad Absorption Lines in Quasars  

NASA Astrophysics Data System (ADS)

This article is an analysis of the broad absorption line properties of a theory of quasars described in a companion paper (Paper I) that differentiates radio-loud quasars from radio-quiet quasars by the magnetic field structure, or lack thereof, in the vortex of an accretion flow around a supermassive rapidly rotating black hole. Nonmagnetic vortices (the radio-quiet case) can initiate radiation pressure-driven jets, as shown in Paper I and these bipolar outflows are candidate broad absorption line regions. The primary emphases of this article are the far-field dynamics and the observational implications of the radiation-driven jets from accretion vortices conjectured to exist in radio-quiet quasars. The well-known confinement problem of the broad line absorbing gas is solved by these hypersonic underexpanded jets as they are collimated kinematically with an opening angle of the order of the inverse of the Mach number. The asymptotic jet velocities are found by a detailed analysis of the force of gravity, continuum radiation pressure, and line-driving forces on the jet plasma. The dynamics are explored through time stationary solutions. However, the general solution is considered to be a superposition of episodic quasistationary funnel ejecta as the accretion flow is most likely dynamically unsteady. The final state outflow is a series of geometrically thin clouds with a distribution of velocities ranging from 0 to ~35,000 km s-1. The most significant implication of this model is that radio-loud quasars (magnetic flux filled accretion vortices) do not have broad absorption line outflows.

Punsly, Brian

1999-12-01

61

A PERVASIVE BROAD COMPONENT IN H I EMISSION LINE PROFILES: TEMPERATURE, TURBULENCE, OR A HELIUM SIGNATURE?  

SciTech Connect

Gaussian analysis of interstellar neutral hydrogen emission profiles has revealed a pervasive broad component with a width on the order of 34 km s{sup -1}. When present, this component can most readily be identified in high galactic latitude directions where the H I profiles are either intrinsically weak or simple. Examination of published data reveals that this characteristic line width has been found in a variety of other H I features including compact high-velocity clouds, very-high-velocity clouds, and the Magellanic Stream. When its presence is accounted for in the analysis of H I profiles, other families of line widths at 14 and 6 km s{sup -1} are clearly revealed. Possible mechanisms for producing this broad background component are discussed, including temperature, turbulence, and the critical ionization velocity effect. A line width on the order of 34 km s{sup -1} would imply a kinetic temperature of 24,000 K, too high to keep the gas neutral; hence it should not be observed in H I emission spectra. Turbulent motions could explain a pervasive broad component, but not why it always has the same numerical value in various classes of H I emission line features. The critical ionization velocity effect hypothesis is intriguing because 34 km s{sup -1} is the value for helium. Clearly, this could be a coincidence but the other prominent distribution peaks correspond to two families of critical ionization velocities of abundant interstellar elements including C, N, and O (about 14 km s{sup -1}) and metals (about 6 km s{sup -1}). Unfortunately, the mechanism by which this effect operates, even in laboratory situations, is not clearly understood. It is suggested that further investigation of the distribution of H I component line widths by allowing for the existence of a pervasive broad underlying component may cast a clearer light on this intriguing phenomenon.

Verschuur, G. L.; Schmelz, J. T., E-mail: gverschr@memphis.ed, E-mail: jschmelz@memphis.ed [Physics Department, University of Memphis, Memphis, TN 38152 (United States)

2010-06-15

62

Probing early stages of AGN evolution: Narrow-Line Seyfert 1s and Broad Absorption Line Quasars  

Microsoft Academic Search

Luminous Narrow-Line Seyfert 1 galaxies (NLS1s) and BAL QSOs share several characteristics indicating a possible relation of these classes of active galactic nuclei (AGN). For example, similar high Eddington accretion rates support the idea that these AGN are in an early stage of their active phase. Generally, the broad and blue-shifted absorption troughs in BAL QSO are associated with high

Matthias Dietrich; Smita Mathur

2010-01-01

63

Broad-band characterization of magnetic and dielectric thin films using a microstrip line  

Microsoft Academic Search

A measurement method for the broad-band determination (100 MHz-10 GHz) of the permeability and permittivity of thin films with thicknesses of 1-10 ?m has been developed. The technique is based on the measurement of the S parameters of a microstrip line loaded with the test sample. The S parameters are measured with a network analyzer. Besides its band width, the

P. Queffelec; M. Le Floc'h; P. Gelin

1998-01-01

64

Polarization of Quasars: Electron Scattering in the Broad Absorption Line Region  

Microsoft Academic Search

It is widely accepted that the broad absorption line region (BALR) exists in most (if not all) quasars with a small covering factor. Recent works showed that the BALR is optically thick to soft and even medium-energy X-rays, with a typical hydrogen column density of a few 1023 to >1024 cm-2. The electron scattering in the thick absorber might contribute

Hui-Yuan Wang; Ting-Gui Wang; Jun-Xian Wang

2005-01-01

65

X-ray monitoring of NGC~4507: X-ray absorption by Broad Line Clouds  

Microsoft Academic Search

We propose a new XMM-Newton monitoring of the X-ray obscured AGN in NGC~4507, with the aim of testing a scenario where the variable X-ray absorption is due to the broad emission line clouds. The identification of these two components is suggested by our previous monitoring of a few other sources (NGC 1365, NGC 4151, UGC 4203), where rapid X-ray absorption

Guido Risaliti

2009-01-01

66

X-Rays from the Highly Polarized Broad Absorption Line QSO CSO 755  

Microsoft Academic Search

We present results from a BeppoSAX observation of the broad absorption line (BAL) QSO CSO 755, which was observed as part of our program to investigate the X-ray properties of highly polarized BAL QSOs. CSO 755 is clearly detected by the BeppoSAX Medium-Energy Concentrator Spectrometers, making it the highest redshift (z=2.88) and most optically luminous (M_V=-27.4) BAL QSO seen in

W. N. Brandt; A. Comastri; S. C. Gallagher; R. M. Sambruna; Th. Boller; A. Laor

1999-01-01

67

DO QUASAR BROAD-LINE VELOCITY WIDTHS ADD ANY INFORMATION TO VIRIAL BLACK HOLE MASS ESTIMATES?  

SciTech Connect

We examine how much information measured broad-line widths add to virial black hole (BH) mass estimates for flux-limited samples of quasars. We do this by comparing the BH mass estimates to those derived by randomly reassigning the quasar broad-line widths to different objects and re-calculating the BH mass. For 9000 BH masses derived from the H{beta} line we find that the distributions of original and randomized BH masses in the M{sub BH}-redshift plane and the M{sub BH}-luminosity plane are formally identical. A two-dimensional Kolmogorov-Smirnov test does not find a difference at >90% confidence. For the Mg II line (32,000 quasars) we do find very significant differences between the randomized and original BH masses, but the amplitude of the difference is still small. The difference for the C IV line (14,000 quasars) is 2{sigma}-3{sigma} and again the amplitude of the difference is small. Subdividing the data into redshift and luminosity bins we find that the median absolute difference in BH mass between the original and randomized data is 0.025, 0.01, and 0.04 dex for H{beta}, Mg II, and C IV, respectively. The maximum absolute difference is always {<=}0.1 dex. We investigate whether our results are sensitive to corrections to Mg II virial masses, such as those suggested by Onken and Kollmeier. These corrections do not influence our results, other than to reduce the significance of the difference between original and randomized BH masses to only 1{sigma}-2{sigma} for Mg II. Moreover, we demonstrate that the correlation between mass residuals and Eddington ratio discussed by Onken and Kollmeier is more directly attributable to the slope of the relation between H{beta} and Mg II line width. The implication is that the measured quasar broad-line velocity widths provide little extra information, after allowing for the mean velocity width. In this case virial estimates are equivalent to M{sub BH}{proportional_to}L{sup {alpha}}, with L/L{sub Edd}{proportional_to}L{sup 1-{alpha}} (with {alpha} {approx_equal} 0.5). This leaves an unanswered question of why the accretion efficiency changes with luminosity in just the right way to keep the mean broad-line widths fixed as a function of luminosity.

Croom, Scott M., E-mail: scroom@physics.usyd.edu.au [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia)

2011-08-01

68

Intervening broad-line region clouds' effects on the optical/ultraviolet spectrum  

NASA Astrophysics Data System (ADS)

Recent X-ray observations of Mrk 766 suggest that broad emission-line region clouds cross our line of sight and produce variable X-ray absorption. Here we investigate what optical/ultraviolet (UV) spectroscopic features would be produced by such 'intervening broad-line region (BLR) clouds' (IBC) crossing our line of sight to the accretion disc, the source of the optical/UV continuum. Although the emission spectrum produced by intervening clouds is identical to the standard BLR model, they may produce absorption features on the optical or UV continuum. Single clouds will have little effect on the optical/UV spectrum because BLR clouds are likely to be much smaller than the accretion disc. This is unlike the X-ray case, where the radiation source is considerably smaller. However, an ensemble of intervening clouds will produce spectroscopic features in the far-ultraviolet including a strong depression between the Lyman limit and Ly?. The amount of the depression will indicate the line-of-sight covering factor of clouds, an unknown quantity that is important for the ionization of the intergalactic medium and the energy budget of active galactic nuclei (AGNs). Comparison with observations suggests that the Spectral Energy Distribution (SED) of Mrk 766 may be affected by IBC that may exist in most of AGNs.

Wang, Ye; Ferland, Gary J.; Hu, Chen; Wang, Jian-Min; Du, Pu

2012-08-01

69

The Lick AGN Monitoring Project 2011: Fe II Reverberation from the Outer Broad-line Region  

NASA Astrophysics Data System (ADS)

The prominent broad Fe II emission blends in the spectra of active galactic nuclei have been shown to vary in response to continuum variations, but past attempts to measure the reverberation lag time of the optical Fe II lines have met with only limited success. Here we report the detection of Fe II reverberation in two Seyfert 1 galaxies, NGC 4593 and Mrk 1511, based on data from a program carried out at Lick Observatory in Spring 2011. Light curves for emission lines including H? and Fe II were measured by applying a fitting routine to decompose the spectra into several continuum and emission-line components, and we use cross-correlation techniques to determine the reverberation lags of the emission lines relative to V-band light curves. In both cases, the measured lag (?cen) of Fe II is longer than that of H?, although the inferred lags are somewhat sensitive to the choice of Fe II template used in the fit. For spectral decompositions done using the Fe II template of Véron-Cetty et al., we find ?cen(Fe II)/?cen(H?) = 1.9 ± 0.6 in NGC 4593 and 1.5 ± 0.3 in Mrk 1511. The detection of highly correlated variations between Fe II and continuum emission demonstrates that the Fe II emission in these galaxies originates in photoionized gas, located predominantly in the outer portion of the broad-line region.

Barth, Aaron J.; Pancoast, Anna; Bennert, Vardha N.; Brewer, Brendon J.; Canalizo, Gabriela; Filippenko, Alexei V.; Gates, Elinor L.; Greene, Jenny E.; Li, Weidong; Malkan, Matthew A.; Sand, David J.; Stern, Daniel; Treu, Tommaso; Woo, Jong-Hak; Assef, Roberto J.; Bae, Hyun-Jin; Buehler, Tabitha; Cenko, S. Bradley; Clubb, Kelsey I.; Cooper, Michael C.; Diamond-Stanic, Aleksandar M.; Hönig, Sebastian F.; Joner, Michael D.; Laney, C. David; Lazarova, Mariana S.; Nierenberg, A. M.; Silverman, Jeffrey M.; Tollerud, Erik J.; Walsh, Jonelle L.

2013-06-01

70

Orientation effects in quasar spectra: the broad- and narrow-line regions  

NASA Astrophysics Data System (ADS)

We use the Sloan Digital Sky Survey, along with the NRAO VLA Sky Survey and the Westerbork Northern Sky Survey to define a sample of 746 radio-loud quasars and measure their 330 MHz-1.4 GHz spectral indexes. Following previous authors we take the radio spectral index as an indicator of the orientation towards the quasars such that more pole-on sources tend to have flatter spectral indexes. We use this proxy for the orientation of quasars to investigate the effect orientation may have on optical spectra. Quasars with flatter spectral indexes tend to be brighter. However, we find no indication of reddening in steep-spectrum quasi-stellar objects (QSOs) to indicate obscuration of the accretion disc by a torus as a possible explanation. Nor do we find increased reddening in the flat-spectrum sources which could imply a contribution from jet-related synchrotron emission. We reproduce a previously described anticorrelation between the width of the Mg II line and radio spectral index that indicates a disc-like geometry for the Mg II broad-line region (BLR). However, in contrast to previous authors we find no such correlation for the C IV line suggesting a more isotropic high-ionization BLR. Both the [O II] and [O III] narrow lines have more flux in steep spectrum sources, while the [O III]/[O II] flux ratio is lower in these sources. To describe both of these effects we propose a simple geometric model in which the narrow-line region (NLR) exists primarily on the surface of optically thick clouds facing the active nucleus and the NLR is stratified such that higher ionization lines are found preferentially closer to the nucleus. Quantitatively we find that orientation may effect the observed strength of narrow lines, as well as ratios between lines, by a factor of ˜2. These findings have implications for the use of [O III] and [O II] emission lines to estimate bolometric luminosities, as well as comparisons between narrow-line luminosity functions for type 1 and 2 objects and the potential of emission-line diagnostic diagrams as an accurate tool with which to distinguish types of active galactic nuclei. Finally we find no evidence that broad-absorption line (BAL) QSOs have a different spectral index distribution to non-BALs although we only have 25 obvious BALs in our sample.

Fine, S.; Jarvis, M. J.; Mauch, T.

2011-03-01

71

Structural basis for HIV-1 gp120 recognition by a germ-line version of a broadly neutralizing antibody  

PubMed Central

Efforts to design an effective antibody-based vaccine against HIV-1 would benefit from understanding how germ-line B-cell receptors (BCRs) recognize the HIV-1 gp120/gp41 envelope spike. Potent VRC01-like (PVL) HIV-1 antibodies derived from the VH1-2*02 germ-line allele target the conserved CD4 binding site on gp120. A bottleneck for design of immunogens capable of eliciting PVL antibodies is that VH1-2*02 germ-line BCR interactions with gp120 are uncharacterized. Here, we report the structure of a VH1-2*02 germ-line antibody alone and a germ-line heavy-chain/mature light-chain chimeric antibody complexed with HIV-1 gp120. VH1-2*02 residues make extensive contacts with the gp120 outer domain, including all PVL signature and CD4 mimicry interactions, but not critical CDRH3 contacts with the gp120 inner domain and bridging sheet that are responsible for the improved potency of NIH45-46 over closely related clonal variants, such as VRC01. Our results provide insight into initial recognition of HIV-1 by VH1-2*02 germ-line BCRs and may facilitate the design of immunogens tailored to engage and stimulate broad and potent CD4 binding site antibodies.

Scharf, Louise; West, Anthony P.; Gao, Han; Lee, Terri; Scheid, Johannes F.; Nussenzweig, Michel C.; Bjorkman, Pamela J.; Diskin, Ron

2013-01-01

72

Broad iron line in the fast spinning neutron-star system 4U 1636-53  

NASA Astrophysics Data System (ADS)

We analysed the X-ray spectra of six observations, simultaneously taken with XMM-Newton and Rossi X-ray Timing Explorer (RXTE), of the neutron-star low-mass X-ray binary 4U 1636-53. The observations cover several states of the source, and therefore a large range of inferred mass accretion rate. These six observations show a broad emission line in the spectrum at around 6.5 keV, likely due to iron. We fitted this line with a set of phenomenological models of a relativistically broadened line, plus a model that accounts for relativistically smeared and ionized reflection from the accretion disc. The latter model includes the incident emission from both the neutron-star surface or boundary layer and the corona that is responsible for the high-energy emission in these systems. From the fits with the reflection model we found that in four out of the six observations the main contribution to the reflected spectrum comes from the neutron-star surface or boundary layer, whereas in the other two observations the main contribution to the reflected spectrum comes from the corona. We found that the relative contribution of these two components is not correlated to the state of the source. From the phenomenological models, we found that the iron line profile is better described by a symmetric, albeit broad, profile. The width of the line cannot be explained only by Compton broadening, and we therefore explored the case of relativistic broadening. We further found that the direct emission from the disc, boundary layer and corona generally evolved in a manner consistent with the standard accretion disc model, with the disc and boundary layer becoming hotter and the disc moving inwards as the source changed from the hard to the soft state. The iron line, however, did not appear to follow the same trend.

Sanna, Andrea; Hiemstra, Beike; Méndez, Mariano; Altamirano, Diego; Belloni, Tomaso; Linares, Manuel

2013-06-01

73

Low-z Mg II Broad Absorption-line Quasars from the Sloan Digital Sky Survey  

NASA Astrophysics Data System (ADS)

We present a sample of 68 low-z Mg II low-ionization broad absorption-line (loBAL) quasars. The sample is uniformly selected from the Sloan Digital Sky Survey Data Release 5 according to the following criteria: (1) redshift 0.4 < z <= 0.8, (2) median spectral S/N>7 pixel-1, and (3) Mg II absorption-line width ?vc >= 1600 km s-1. The last criterion is a trade-off between the completeness and consistency with respect to the canonical definition of BAL quasars that have the "balnicity index" BI>0 in C IV BAL. We adopted such a criterion to ensure that ~90% of our sample are classical BAL quasars and the completeness is ~80%, based on extensive tests using high-z quasar samples with measurements of both C IV and Mg II BALs. We found (1) Mg II BAL is more frequently detected in quasars with narrower H? emission line, weaker [O III] emission line, stronger optical Fe II multiplets, and higher luminosity. In term of fundamental physical parameters of a black hole accretion system, loBAL fraction is significantly higher in quasars with a higher Eddington ratio than those with a lower Eddington ratio. The fraction is not dependent on the black hole mass in the range concerned. The overall fraction distribution is broad, suggesting a large range of covering factor of the absorption material. (2) [O III]-weak loBAL quasars averagely show undetected [Ne V] emission line and a very small line ratio of [Ne V] to [O III]. However, the line ratio in non-BAL quasars, which is much larger than that in [O III]-weak loBAL quasars, is independent of the strength of the [O III] line. (3) loBAL and non-loBAL quasars have similar colors in near-infrared to optical band but different colors in ultraviolet. (4) Quasars with Mg II absorption lines of intermediate width are indistinguishable from the non-loBAL quasars in optical emission line properties but their colors are similar to loBAL quasars, redder than non-BAL quasars. We also discuss the implication of these results.

Zhang, Shaohua; Wang, Ting-Gui; Wang, Huiyuan; Zhou, Hongyan; Dong, Xiao-Bo; Wang, Jian-Guo

2010-05-01

74

Broad P V Absorption in the QSO PG 1254+047: Column Densities, Ionizations, and Metal Abundances in Broad Absorption Line Winds  

Microsoft Academic Search

This paper discusses the detection of P V lambda lambda 1118, 1128 and other broad absorption lines (BALs) in archival Hubble Space Telescope spectra of the low-redshift BAL QSO PG 1254+047. The P V identification is secured by excellent redshift and profile coincidences with the other BALs, such as C IV lambda lambda 1548, 1550 and Si IV lambda lambda

Fred Hamann

1998-01-01

75

The Broad-Line Region of NGC 4151: its Structure and Physical Characteristics  

NASA Astrophysics Data System (ADS)

The optical spectral variability of NGC 4151 is modeled on the basis of the observational data by Kaspi et al. (1996) and the theoretical model of the broad-line region by Shevchenko (1984, 1985). One of the purposes of the modelling consists in interpretation of the difference in time lags of the observed variations in the H-alpha line (Lyutyi and Cherepashchuk 1971, Cherepashchuk and Lyutyi 1973) and the H? line (Antonucci and Cohen 1983) with respect to the observed variations in continuum. In agreement with conclusions by Shevchenko (1984, 1985), it is found that the difference is explained by strong nonlinearity of the dependence of the luminosity of a typical BLR cloud in the H-alpha line upon the value of the flux of ionizing continuum at the cloud. This nonlinearity is taken into account in numerical modeling of an AGN emission-line lightcurve for the first time. The values of parameters of the NGC 4151 BLR model are retrieved, that allow to judge on the structure and physical characteristics of the near-nuclear region. In particular, new estimates of the geometrical size of the BLR have been made, independent of the choice of the emission line in the lightcurve analysis.

Melnikov, Alexander V.; Shevchenko, Ivan I.

2007-08-01

76

OPTICAL MONITORING OF THE BROAD-LINE RADIO GALAXY 3C 390.3  

SciTech Connect

We have undertaken a new ground-based monitoring campaign on the broad-line radio galaxy 3C 390.3 to improve the measurement of the size of the broad emission-line region and to estimate the black hole mass. Optical spectra and g-band images were observed in late 2005 for three months using the 2.4 m telescope at MDM Observatory. Integrated emission-line flux variations were measured for the hydrogen Balmer lines H{alpha}, H{beta}, H{gamma}, and for the helium line He II{lambda}4686, as well as g-band fluxes and the optical active galactic nucleus (AGN) continuum at {lambda} = 5100 A. The g-band fluxes and the optical AGN continuum vary simultaneously within the uncertainties, {tau}{sub cent} (0.2 {+-} 1.1) days. We find that the emission-line variations are delayed with respect to the variable g-band continuum by {tau}(H{alpha}) 56.3{sup +2.4}{sub -6.6} days, {tau}(H{beta}) = 44.3{sup +3.0}{sub -3.3} days, {tau}(H{gamma}) = 58.1{sup +4.3}{sub -6.1} days, and {tau}(He II 4686) = 22.3{sup +6.5}{sub -3.8} days. The blue and red peaks in the double-peaked line profiles, as well as the blue and red outer profile wings, vary simultaneously within {+-}3 days. This provides strong support for gravitationally bound orbital motion of the dominant part of the line-emitting gas. Combining the time delay of the strong Balmer emission lines of H{alpha} and H{beta} and the separation of the blue and red peaks in the broad double-peaked profiles in their rms spectra, we determine M {sup vir}{sub bh} = 1.77{sup +0.29}{sub -0.31} Multiplication-Sign 10{sup 8} M{sub Sun} and using {sigma}{sub line} of the rms spectra M {sup vir}{sub bh} 2.60{sup +0.23}{sub -0.31} Multiplication-Sign 10{sup 8} M{sub Sun} for the central black hole of 3C 390.3, respectively. Using the inclination angle of the line-emitting region which is measured from superluminal motion detected in the radio range, accretion disk models to fit the optical double-peaked emission-line profiles, and X-ray observations, the mass of the black hole amounts to M{sub bh} = 0.86{sup +0.19}{sub -0.18} Multiplication-Sign 10{sup 9} M{sub Sun} (peak separation) and M{sub bh} 1.26{sup +0.21}{sub -0.16} Multiplication-Sign 10{sup 9} M{sub Sun} ({sigma}{sub line}), respectively. This result is consistent with the black hole masses indicated by simple accretion disk models to describe the observed double-peaked profiles, derived from the stellar dynamics of 3C 390.3, and with the AGN radius-luminosity relation. Thus, 3C 390.3 as a radio-loud AGN with a low Eddington ratio, L{sub edd}/L{sub bol} = 0.02, follows the same AGN radius-luminosity relation as radio-quiet AGNs.

Dietrich, Matthias; Peterson, Bradley M.; Grier, Catherine J.; Bentz, Misty C.; Eastman, Jason; Frank, Stephan; Gonzalez, Raymond; Marshall, Jennifer L.; DePoy, Darren L.; Prieto, Jose L., E-mail: dietrich@astronomy.ohio-state.edu [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)

2012-09-20

77

Starburst-AGN Connections: Clues from Poststarburst Broad Line AGN in the SDSS DR2  

NASA Astrophysics Data System (ADS)

A sample of 74 poststarburst broad line AGN are selected from the Sloan Digital Sky Survey Data Release 2 (SDSS DR2). Because in these so-called "Q+A"s, we can catch with a smoking gun the change of the recent star formation in the host galaxies, and in the meantime, view the nuclear activity directly, the present sample suits to address the important yet long debated issue concerning the physical link between starburst and AGN phenomena. We find that more than half of the Q+As can be classified as Narrow Line Seyfert 1 galaxies (NLS1s) and the mass accretion rate of the sample is significantly higher than that of optically-selected quasars. If these engorging objects, especially the NLS1s are indeed AGN in their early evolution stage, this result strongly suggests that the nuclear activity be driven by starburst with a time delay of ˜ a few hundred Myr.

Zhou, H.; Wang, T.; Dong, X.; Wang, J.; Lu, H.

78

Reverberation and Photoionization Estimates of the Broad-line Region Radius in Low-z Quasars  

NASA Astrophysics Data System (ADS)

Black hole mass estimation in quasars, especially at high redshift, involves the use of single-epoch spectra with signal-to-noise ratio and resolution that permit accurate measurement of the width of a broad line assumed to be a reliable virial estimator. Coupled with an estimate of the radius of the broad-line region (BLR) this yields the black hole mass M BH. The radius of the BLR may be inferred from an extrapolation of the correlation between source luminosity and reverberation-derived r BLR measures (the so-called Kaspi relation involving about 60 low-z sources). We are exploring a different method for estimating r BLR directly from inferred physical conditions in the BLR of each source. We report here on a comparison of r BLR estimates that come from our method and from reverberation mapping. Our "photoionization" method employs diagnostic line intensity ratios in the rest-frame range 1400-2000 Å (Al III ?1860/Si III] ?1892, C IV ?1549/Al III ?1860) that enable derivation of the product of density and ionization parameter with the BLR distance derived from the definition of the ionization parameter. We find good agreement between our estimates of the density, ionization parameter, and r BLR and those from reverberation mapping. We suggest empirical corrections to improve the agreement between individual photoionization-derived r BLR values and those obtained from reverberation mapping. The results in this paper can be exploited to estimate M BH for large samples of high-z quasars using an appropriate virial broadening estimator. We show that the width of the UV intermediate emission lines are consistent with the width of H?, thereby providing a reliable virial broadening estimator that can be measured in large samples of high-z quasars.

Negrete, C. Alenka; Dultzin, Deborah; Marziani, Paola; Sulentic, Jack W.

2013-07-01

79

Dynamically evolving Mg II broad absorption line flow in SDSS J133356.02+001229.1  

NASA Astrophysics Data System (ADS)

We report a dynamically evolving low-ionization broad absorption line (BAL) flow in the QSO SDSS J133356.02+001229.1 (at zem˜ 0.9197). These observations are part of our ongoing monitoring of low-ionization BAL QSOs with the 2-m telescope at IUCAA Girawali Observatory (IGO). The broad Mg II absorption with an ejection velocity of 1.7 × 104 km s-1, found in the Sloan Digital Sky Survey (SDSS) spectra, has disappeared completely in our IGO spectra. We found an emerging new component at an ejection velocity of 2.8 × 104 km s-1. During our monitoring period this component has shown strong evolution both in its velocity width and optical depth and nearly disappeared in our latest observations. Acceleration of a low-velocity component seen in SDSS spectrum to a higher velocity is unlikely as the Mg II column densities are always observed to be higher for the new component. We argue that the observed variations may not be related to ionization changes and are consistent with absorption produced by multistreaming flow transiting across our line of sight. We find a possible connection between flux variation of the QSO and N(Mg II) of the newly emerged component. This could mean the ejection being triggered by changes in the accretion disc or dust reddening due to the outflowing gas.

Vivek, M.; Srianand, R.; Mahabal, A.; Kuriakose, V. C.

2012-03-01

80

H? line profiles for a sample of supergiant HII regions. II. Broad, low intensity components  

NASA Astrophysics Data System (ADS)

We analyze the broad, low intensity, high velocity components that are seen in the H? line profiles for a sample of HII regions. These HII regions are chosen from among the brightest and most isolated in a sample of spiral galaxies for which we have photometric and spectroscopic data: NGC 157, NGC 3631, NGC 6764, NGC 3344, NGC 4321, NGC 5364, NGC 5055, NGC 5985, and NGC 7479. We confirm that the line profiles of most of these bright, giant extragalactic HII regions contain broad kinematic components of low intensity, but high velocity, that we denote as wings. We analyze these components, deriving emission measures, central velocities, and velocity dispersions of the blue and red features, which are similar. We interpret these components as expanding shells within the HII regions and produced by the stellar winds from the ionizing stars. We compare the kinetic energies of these expanding shells with the kinetic energy available from the stellar winds. If we allow for the hypothesis that the brightest HII regions are density bounded, we show that, for these HII regions, the stellar wind mechanism can explain the observed shell kinetic energies.

Rozas, M.; Richer, M. G.; López, J. A.; Relaño, M.; Beckman, J. E.

2006-08-01

81

Broad Balmer line emission and cosmic ray acceleration efficiency in supernova remnant shocks  

NASA Astrophysics Data System (ADS)

Context. Balmer emission may be a powerful diagnostic tool for testing the paradigm of cosmic ray (CR) acceleration in young supernova remnant (SNR) shocks. The width of the broad Balmer line is a direct indicator of the downstream plasma temperature. In the case of efficient particle acceleration, an appreciable fraction of the total kinetic energy of the plasma is channeled into CRs, therefore the downstream temperature decreases and so does the broad Balmer line width. This width also depends on the level of thermal equilibration between ions and neutral hydrogen atoms in the downstream. Since generally only a few charge exchange (CE) reactions occur before ionization in young SNR shocks, equilibration between ions and neutrals is not reached, and a kinetic description of the neutrals is required to properly compute Balmer emission. Aims: We provide a method for calculating Balmer emission using a self-consistent description of the shock structure in the presence of neutrals and CRs, which also accounts for the non-Maxwellian distribution of neutrals. Methods: We use a recently developed semi-analytical approach, where neutral particles, ionized plasma, accelerated particles, and magnetic fields are all coupled together through the mass, momentum, and energy flux-conservation equations. The distribution of neutrals is obtained from the full Boltzmann equation in velocity space, coupled to Maxwellian ions through ionization and CE processes. The computation is also an improvement over previous work thanks to a better approximation of the atomic interaction rates. Results: We find that for shock speeds ?2500 km s-1, the distribution of broad neutrals never approaches a Maxwellian and its moments differ from those of the ionized component. These differences lead to a smaller FWHM than predicted in previous calculations, where thermalization was assumed. Conclusions: The method presented here provides a realistic estimate of particle acceleration efficiency in Balmer-dominated shocks.

Morlino, G.; Blasi, P.; Bandiera, R.; Amato, E.

2013-10-01

82

First Constraints on Black Hole Spin in Broad Iron Line AGN  

NASA Astrophysics Data System (ADS)

Black holes are arguably the simplest objects in nature, with an ability to be completely defined by two mathematical quantities: mass and spin. Spin, being a general relativistic effect, is the more difficult to discern of the two. One of the most promising and robust methods for constraining this quantity relies on modeling the relativistically altered shape of the iron-K line emitted from the accretion disk around the black hole. With this in mind, I have expanded upon previous emission line model codes to create a new relativistic emission line model, called kerrdisk, which allows the black hole spin to be fit as a free parameter. This allows us to robustly constrain the angular momentum of a black hole for the first time. Herein I present the results of spectral fitting of this model to several AGN with robustly observed broad iron lines in an effort to perform the very first statistically robust study of black hole spin distribution in these types of sources. This is a crucial first step toward taking a census of black hole spin in both AGN and GBHCs. I gratefully acknowledge funding from NSF grant AST0205990, which has contributed to this research.

Brenneman, Laura

2006-12-01

83

The rest-frame ultraviolet properties of radio-loud broad absorption line quasars  

NASA Astrophysics Data System (ADS)

We recently presented radio observations of a large sample of radio-loud broad absorption line (BAL) quasars from the Sloan Digital Sky Survey (SDSS) and Faint Images of the Radio Sky at Twenty-cm surveys, as well as a well matched sample of unabsorbed quasars, primarily to measure their radio spectral indices and estimate ensemble orientations. Here, we analyse the SDSS spectra of these samples and compare the rest-frame ultraviolet properties of radio-loud BAL and non-BAL quasars. Ultraviolet properties include the continuum shape, emission-line measurements of C IV, Al III, C III], Fe II and Mg II, and BAL properties including the balnicity index, absorption index and minimum and maximum outflow velocities. We find that radio-loud BAL quasars have similar ultraviolet properties compared to radio-loud non-BAL sources, though they do appear to have redder continua and stronger Fe II emission, which is consistent with what is found for radio-quiet BAL sources. No correlations exist between outflow properties and orientation (radio spectral index), suggesting that BAL winds along any line of sight are driven by the same mechanisms. There are also few correlations between spectral index and other properties. We conclude that BAL outflows occur along all lines of sight with similar strengths and velocities.

DiPompeo, M. A.; Brotherton, M. S.; Cales, S. L.; Runnoe, J. C.

2012-12-01

84

Interactions and Developmental Effects of Mutations in the Broad-Complex of Drosophila melanogaster  

Microsoft Academic Search

The 2B5 region on the X chromosome of Drosophila melanogaster forms an early ecdysone puff at the end of the third larval instar. The region contains a complex genetic locus, the Broad-Complex (BR-C) composed of four groups of fully complementing (br, rbp, l(l)2Bc, and 1( l)2Bd) alleles, and classes of noncomplementing (nprl) and partially noncomplementing I( l)2Bab alleles. BR-C mutants

Istvan Kiss; Amy H. Beaton; Jil Tardiff; Dianne Fristrom; James W. Fristrom

1988-01-01

85

Implications of dramatic broad absorption line variability in the quasar FBQS J1408+3054  

NASA Astrophysics Data System (ADS)

We have observed a dramatic change in the spectrum of the formerly heavily absorbed 'overlapping-trough' iron low-ionization broad absorption line (FeLoBAL) quasar FBQS J1408+3054. Over a time-span of between 0.6 to 5 rest-frame years, the Mg II trough outflowing at 12 000 km s-1 decreased in equivalent width by a factor of 2 and the Fe II troughs at the same velocity disappeared. The most likely explanation for the variability is that a structure in the BAL outflow moved out of our line of sight to the ultraviolet continuum emitting region of the quasar's accretion disc. Given the size of that region, this structure must have a transverse velocity of between 2600 km s-1 and 22 000 km s-1. In the context of a simple outflow model, we show that this BAL structure is located between approximately 5800 and 46 000 Schwarzschild radii from the black hole. That distance corresponds to 1.7 to 14 pc, 11 to 88 times farther from the black hole than the H? broad-line region. The high velocities and the parsec-scale distance for at least this one FeLoBAL outflow mean that not all FeLoBAL outflows can be associated with galaxy-scale outflows in ultraluminous infrared galaxies transitioning to unobscured quasars. The change of FBQS J1408+3054 from an FeLoBAL to a LoBAL quasar also means that if (some) FeLoBAL quasars have multiwavelength properties which distinguish them from HiBAL quasars, then some LoBAL quasars will share those properties. Finally, we extend previous work on how multiple-epoch spectroscopy of BAL and non-BAL quasars can be used to constrain the average lifetime of BAL episodes (currently >60 rest-frame years at 90 per cent confidence).

Hall, P. B.; Anosov, K.; White, R. L.; Brandt, W. N.; Gregg, M. D.; Gibson, R. R.; Becker, R. H.; Schneider, D. P.

2011-03-01

86

BROAD COMPONENTS IN OPTICAL EMISSION LINES FROM THE ULTRA-LUMINOUS X-RAY SOURCE NGC 5408 X-1  

SciTech Connect

High-resolution optical spectra of the ultra-luminous X-ray source (ULX) NGC 5408 X-1 show a broad component with a width of {approx}750 km s{sup -1} in the He II and H{beta} lines in addition to the narrow component observed in these lines and [O III]. Reanalysis of moderate-resolution spectra shows a similar broad component in the He II line. The broad component likely originates in the ULX system itself, probably in the accretion disk. The central wavelength of the broad He II line is shifted by 252 {+-} 47 km s{sup -1} between the two observations. If this shift represents motion of the compact object, then its mass is less than {approx}1800 M{sub sun}.

Cseh, D.; Corbel, S. [Laboratoire Astrophysique des Interactions Multi-echelles (UMR 7158), CEA/DSM-CNRS-Universite Paris Diderot, CEA Saclay, F-91191 Gif sur Yvette (France); Grise, F.; Kaaret, P., E-mail: david.cseh@cea.fr [Department of Physics and Astronomy, University of Iowa, Van Allen Hall, Iowa City, IA 52242 (United States)

2011-02-10

87

Peculiar Broad Absorption Line Quasars Found in The Digitized Palomar Observatory Sky Survey  

NASA Astrophysics Data System (ADS)

With the recent release of large (i.e., >~100 million objects), well-calibrated photometric surveys, such as Digitized Palomar Observatory Sky Survey (DPOSS), Two Micron All Sky Survey, and Sloan Digital Sky Survey, spectroscopic identification of important targets is no longer a simple issue. In order to enhance the returns from a spectroscopic survey, candidate sources are often preferentially selected to be of interest, such as brown dwarfs or high-redshift quasars. This approach, while useful for targeted projects, risks missing new or unusual species. We have, as a result, taken the alternative path of spectroscopically identifying interesting sources with the sole criterion being that they are in low-density areas of the g-r and r-i color space defined by DPOSS. In this paper, we present three peculiar broad absorption line quasars that were discovered during this spectroscopic survey, demonstrating the efficacy of this approach. PSS J0052+2405 is an iron low-ionization broad absorption line (LoBAL) quasar at a redshift z=2.4512+/-0.0001 with very broad absorption from many species. PSS J0141+3334 is a reddened LoBAL quasar at z=3.005+/-0.005 with no obvious emission lines. PSS J1537+1227 is an iron LoBAL at a redshift of z=1.212+/-0.007 with strong narrow Mg II and Fe II emission. Follow-up high-resolution spectroscopy of these three quasars promises to improve our understanding of BAL quasars. The sensitivity of particular parameter spaces, in this case a two-color space, to the redshift of these three sources is dramatic, raising questions about traditional techniques of defining quasar populations for statistical analysis. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Brunner, Robert J.; Hall, Patrick B.; Djorgovski, S. George; Gal, R. R.; Mahabal, A. A.; Lopes, P. A. A.; de Carvalho, R. R.; Odewahn, S. C.; Castro, S.; Thompson, D.; Chaffee, F.; Darling, J.; Desai, V.

2003-07-01

88

Analysing the Suzaku spectra of the broad-line Seyfert 1 galaxy CBS 126  

NASA Astrophysics Data System (ADS)

We analysed new simultaneous Suzaku and Swift data of the broad-line Seyfert 1 (BLS1) galaxy CBS 126. A clear Fe emission line and a strong soft excess are present in the source spectra. We fit the spectra with a relativistic reflection model and find that the model tends to fit the data with a high iron abundance possibly due to the large soft excess present. By checking the difference and the rms spectra, we find that there is likely an absorption edge at ˜0.89 keV, which might be caused by oxygen or neon. We also produced an analysis of the time-resolved spectra in order to examine the existence of the edge. Although high iron abundance is required more in the time-resolved spectra, a model of solar iron abundance together with an absorption edge gives a more physical explanation. Variation of the ionization parameter is an alternative, plausible explanation for the excess seen in the difference spectra. It is difficult to know if there are warm absorbers in this source from the current data. To further investigate the presence of possible warm absorbers, higher signal-to-noise ratio low-energy data are needed. The work presented here tentatively suggests that the spectra of a BLS1 galaxy can be explained by a relativistic reflection model similar to that often seen in their narrow-line cousins.

Chiang, Chia-Ying; Reis, R. C.; Fabian, A. C.; Grupe, D.; Tsuruta, S.

2012-09-01

89

A Detailed Photoionization Study of the Broad Line Region of NGC 5548  

NASA Astrophysics Data System (ADS)

NGC 5548 probably has the best-studied broad line region {BLR} of any AGN. It therefore provides an excellent laboratory for investigating many fundamental BLR questions. We propose to use the large set of HST NGC 5548 spectra taken in 1993 to {a} test photoionization analyzes of BLR clouds, {b} attempt to unravel the various emission line components, and {c} understand how the BLR gas is moving. This data set is uniquely suited to this because of the excellent sampling, high signal-to-noise ratio and large sample of contemporaneous optical spectra available. Because we know the distribution of the BLR gas in NGC 5548 better than in any other AGN and because the multi-wavelength variability history is known, many major uncertainties in previous BLR studies are greatly reduced. We will be using Gary Ferland's photoionization code ``CLOUDY'' to derive physical conditions as a function of both projected velocity and time. The key ingredient in our proposed study is requiring consistency in derived conditions as NGC 5548 varied in continuum and line strength by almost a factor of two during the 1993 monitoring. From this we hope to be able to separate out the various kinematic components and understand the gas motions. We are particularly interested in evaluating disk and disk-plus-wind models

Gaskell, C.

2003-07-01

90

Star-disk collisions in active galactic nuclei and the origin of the broad line region  

SciTech Connect

Stars of a cluster surrounding the central black hole in an AGN will collide with the accretion disk. For a central black hole of 10{sup 8} M{circle dot} and a cluster with 10{sup 7} {minus} 10{sup 8} stars within a parsec, one estimates that {approximately}10{sup 4} such collisions will occur per year. Collisions are hypersonic (Mach number M {much gt} 1). Some of the wake of the star -- the disk material shocked by its passage -- will follow it out of the disk. Such star tails'' with the estimated masses {delta}m {approximately} 10{sup 25} {minus} 10{sup 27} g subsequently expand, cool and begin to recombine. We propose that -- when illuminated by the ionizing flux from the central source -- they are likely to be the origin of the observed broad emission lines.

Zurek, W.H.; Colgate, S.A. (Los Alamos National Lab., NM (United States)); Siemiginowska, A. (Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States))

1991-12-05

91

Star-disk collisions in active galactic nuclei and the origin of the broad line region  

SciTech Connect

Stars of a cluster surrounding the central black hole in an AGN will collide with the accretion disk. For a central black hole of 10{sup 8} M{circle_dot} and a cluster with 10{sup 7} {minus} 10{sup 8} stars within a parsec, one estimates that {approximately}10{sup 4} such collisions will occur per year. Collisions are hypersonic (Mach number M {much_gt} 1). Some of the wake of the star -- the disk material shocked by its passage -- will follow it out of the disk. Such ``star tails`` with the estimated masses {delta}m {approximately} 10{sup 25} {minus} 10{sup 27} g subsequently expand, cool and begin to recombine. We propose that -- when illuminated by the ionizing flux from the central source -- they are likely to be the origin of the observed broad emission lines.

Zurek, W.H.; Colgate, S.A. [Los Alamos National Lab., NM (United States); Siemiginowska, A. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

1991-12-05

92

Broad line and multi-wave luminosity relations in Fermi FSRQs  

NASA Astrophysics Data System (ADS)

We study broad line and multi-wave luminosity relations for 80 flat-spectrum radio quasars (FSRQs) detected by Fermi LAT. Our results are as follows: for FSRQs, the correlations between log L ? and log L BLR, between log L X and log L BLR, between log L O and log L BLR, between log L R and log L BLR are significant; the correlation between log L IR and log L BLR ( P=0.08) is not significant, but might be refereed as a "trend" of significant correlation. These results support a close link between jet formation and accretion disk, and the L ? - L BLR correlation suggests that the radiation mechanism of the ?-ray emission in FSRQs is likely to be inverse Compton scattering of seed photons from BLR or outflowing BLR.

Xiong, D. R.; Zhang, H. J.; Zhang, X.; Zheng, Y. G.; Yi, T. F.; Liu, W. G.; Cha, Y. J.; Li, B. J.

2013-06-01

93

Evolution and Hydrodynamics of the Very Broad X-Ray Line Emission in SN 1987A  

NASA Astrophysics Data System (ADS)

Observations of SN 1987A by the Chandra High Energy Transmission Grating (HETG) in 1999 and the XMM-Newton Reflection Grating Spectrometer (RGS) in 2003 show very broad (v-b) lines with a full width at half-maximum (FWHM) of order 104 km s-1 at these times the blast wave (BW) was primarily interacting with the H II region around the progenitor. Since then, the X-ray emission has been increasingly dominated by narrower components as the BW encounters dense equatorial ring (ER) material. Even so, continuing v-b emission is seen in the grating spectra suggesting that the interaction with H II region material is ongoing. Based on the deep HETG 2007 and 2011 data sets, and confirmed by RGS and other HETG observations, the v-b component has a width of 9300 ± 2000 km s-1 FWHM and contributes of order 20% of the current 0.5-2 keV flux. Guided by this result, SN 1987A's X-ray spectra are modeled as the weighted sum of the non-equilibrium-ionization emission from two simple one-dimensional hydrodynamic simulations; this "2 × 1D" model reproduces the observed radii, light curves, and spectra with a minimum of free parameters. The interaction with the H II region (?init ? 130 amu cm-3, ± 15° opening angle) produces the very broad emission lines and most of the 3-10 keV flux. Our ER hydrodynamics, admittedly a crude approximation to the multi-D reality, gives ER densities of ~104 amu cm-3, requires dense clumps (×5.5 density enhancement in ~30% of the volume), and predicts that the 0.5-2 keV flux will drop at a rate of ~17% per year once no new dense ER material is being shocked.

Dewey, D.; Dwarkadas, V. V.; Haberl, F.; Sturm, R.; Canizares, C. R.

2012-06-01

94

Variability in quasar broad absorption line outflows - III. What happens on the shortest time-scales?  

NASA Astrophysics Data System (ADS)

Broad absorption lines (BALs) in quasar spectra are prominent signatures of high-velocity outflows, which might be present in all quasars and could be a major contributor to feedback to galaxy evolution. Studying the variability in these BALs allows us to further our understanding of the structure, evolution and basic physical properties of the outflows. This is the third paper in a series on a monitoring programme of 24 luminous BAL quasars at redshifts 1.2 < z < 2.9. We focus here on the time-scales of variability in C IV ?1549 BALs in our full multi-epoch sample, which covers time-scales from 0.02 to 8.7 yr in the quasar rest frame. Our sample contains up to 13 epochs of data per quasar, with an average of seven epochs per quasar. We find that both the incidence and the amplitude of variability are greater across longer time-scales. Part of our monitoring programme specifically targeted half of these BAL quasars at rest-frame time-scales ?2 months. This revealed variability down to the shortest time-scales we probe (8-10 d). Observed variations in only portions of BAL troughs or in lines that are optically thick suggest that at least some of these changes are caused by clouds (or some type of outflow substructures) moving across our lines of sight. In this crossing cloud scenario, the variability times constrain both the crossing speeds and the absorber locations. Specific results also depend on the emission and absorption geometries. We consider a range of geometries and use Keplerian rotational speeds to derive a general relationship between the variability times, crossing speeds and outflow locations. Typical variability times of the order of ˜1 yr indicate crossing speeds of a few thousand km s-1 and radial distances ˜1 pc from the central black hole. However, the most rapid BAL changes occurring in 8-10 d require crossing speeds of 17 000-84 000 km s-1 and radial distances of only 0.001-0.02 pc. These speeds are similar to or greater than the observed radial outflow speeds, and the inferred locations are within the nominal radius of the broad emission-line region.

Capellupo, D. M.; Hamann, F.; Shields, J. C.; Halpern, J. P.; Barlow, T. A.

2013-03-01

95

The Discovery of the First He I?10830 Broad Absorption Line Quasar  

NASA Astrophysics Data System (ADS)

We report the discovery of the first He I*?10830 broad absorption line quasar FBQS J1151+3822. Using new infrared and optical spectra, as well as the SDSS spectrum, we extracted the apparent optical depth profiles as a function of velocity of the 3889 Å and 10830 Å He I* absorption lines. Since these lines have the same lower levels, inhomogeneous absorption models could be used to extract the average true He I* column density; the log of that number was 14.9. The total hydrogen column density was obtained using Cloudy models. A range of ionization parameters and densities were allowed, with the lower limit on the ionization parameter of log U = -1.4 determined by the requirement that there be sufficient He I*, and the upper limit on the density of log n = 8 determined by the lack of Balmer absorption. Simulated UV spectra showed that the ionization parameter could be further constrained in principle using a combination of low- and high-ionization lines (such as Mg II and P V), but the only density-sensitive line predicted to be observable and not significantly blended was C III?1176. We estimated the outflow rate and kinetic energy, finding them to be consistent but on the high side compared with analyses of other objects. Assuming that radiative line driving is the responsible acceleration mechanism, a force multiplier model was constructed. A dynamical argument using the model results strongly constrained the density to be log n >= ~7. Consequently, the log hydrogen column density is constrained to be between 21.7 and 22.9, the mass outflow rate to be between 11 and 56 solar masses per year, the ratio of the mass outflow rate to the accretion rate to be between 1.2 and 5.8, and the kinetic energy to be between 1 and 5 × 1044 erg s-1. We discuss the advantages of using He I* to detect high column density BALQSOs and measure their properties. We find that the large ?fik ratio of 23.3 between the 10830 Å and 3889 Å components makes He I* analysis sensitive to a large range of high column densities. We discuss the prospects for finding other He I*?10830 BALQSOs and examine the advantages of studying the properties of a sample identified using He I*.

Leighly, Karen M.; Dietrich, Matthias; Barber, Sara

2011-02-01

96

BROAD ABSORPTION LINE DISAPPEARANCE ON MULTI-YEAR TIMESCALES IN A LARGE QUASAR SAMPLE  

SciTech Connect

We present 21 examples of C IV broad absorption line (BAL) trough disappearance in 19 quasars selected from systematic multi-epoch observations of 582 bright BAL quasars (1.9 < z < 4.5) by the Sloan Digital Sky Survey-I/II (SDSS-I/II) and SDSS-III. The observations span 1.1-3.9 yr rest-frame timescales, longer than have been sampled in many previous BAL variability studies. On these timescales, Almost-Equal-To 2.3% of C IV BAL troughs disappear and Almost-Equal-To 3.3% of BAL quasars show a disappearing trough. These observed frequencies suggest that many C IV BAL absorbers spend on average at most a century along our line of sight to their quasar. Ten of the 19 BAL quasars showing C IV BAL disappearance have apparently transformed from BAL to non-BAL quasars; these are the first reported examples of such transformations. The BAL troughs that disappear tend to be those with small-to-moderate equivalent widths, relatively shallow depths, and high outflow velocities. Other non-disappearing C IV BALs in those nine objects having multiple troughs tend to weaken when one of them disappears, indicating a connection between the disappearing and non-disappearing troughs, even for velocity separations as large as 10,000-15,000 km s{sup -1}. We discuss possible origins of this connection including disk-wind rotation and changes in shielding gas.

Filiz Ak, N.; Brandt, W. N.; Schneider, D. P. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Hall, P. B. [Department of Physics and Astronomy, York University, 4700 Keele St., Toronto, Ontario M3J 1P3 (Canada); Anderson, S. F.; Gibson, R. R. [Astronomy Department, University of Washington, Seattle, WA 98195 (United States); Lundgren, B. F. [Department of Physics, Yale University, New Haven, CT 06511 (United States); Myers, A. D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Petitjean, P. [Institut d'Astrophysique de Paris, Universite Paris 6, F-75014, Paris (France); Ross, Nicholas P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 92420 (United States); Shen Yue [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51, Cambridge, MA 02138 (United States); York, D. G. [Department of Astronomy and Astrophysics, and Enrico Fermi Institute, University of Chicago, 5640 S. Ellis Ave., Chicago, IL 60637 (United States); Bizyaev, D.; Brinkmann, J.; Malanushenko, E.; Oravetz, D. J.; Pan, K.; Simmons, A. E. [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059 (United States); Weaver, B. A., E-mail: nfilizak@astro.psu.edu [Center for Cosmology and Particle Physics, New York University, New York, NY 10003 (United States)

2012-10-01

97

An Infrared Excess Identified in Radio-loud Broad Absorption Line Quasars  

NASA Astrophysics Data System (ADS)

If broad absorption line (BAL) quasars represent a high-covering-fraction evolutionary state (even if this is not the sole factor governing the presence of BALs), it is expected that they should show an excess of mid-infrared radiation compared to normal quasars. Some previous studies have suggested that this is not the case. We perform the first analysis of the IR properties of radio-loud BAL quasars, using IR data from WISE and optical (rest-frame ultraviolet) data from SDSS, and compare the BAL quasar sample with a well-matched sample of unabsorbed quasars. We find a statistically significant excess in the mid- to near-infrared luminosities of BAL quasars, particularly at rest-frame wavelengths of 1.5 and 4 ?m. Our sample was previously used to show that BALs are observed along many lines of sight toward quasars, but with an overabundance of more edge-on sources, suggesting that orientation factors into the appearance of BALs. The evidence here—of a difference in IR luminosities between BAL quasars and unabsorbed quasars—can be ascribed to evolution. This suggests that a merging of the current BAL paradigms is needed to fully describe the class.

DiPompeo, M. A.; Runnoe, J. C.; Brotherton, M. S.; Myers, A. D.

2013-01-01

98

Broad Absorption Line Disappearance on Multi-year Timescales in a Large Quasar Sample  

NASA Astrophysics Data System (ADS)

We present 21 examples of C IV broad absorption line (BAL) trough disappearance in 19 quasars selected from systematic multi-epoch observations of 582 bright BAL quasars (1.9 < z < 4.5) by the Sloan Digital Sky Survey-I/II (SDSS-I/II) and SDSS-III. The observations span 1.1-3.9 yr rest-frame timescales, longer than have been sampled in many previous BAL variability studies. On these timescales, ?2.3% of C IV BAL troughs disappear and ?3.3% of BAL quasars show a disappearing trough. These observed frequencies suggest that many C IV BAL absorbers spend on average at most a century along our line of sight to their quasar. Ten of the 19 BAL quasars showing C IV BAL disappearance have apparently transformed from BAL to non-BAL quasars; these are the first reported examples of such transformations. The BAL troughs that disappear tend to be those with small-to-moderate equivalent widths, relatively shallow depths, and high outflow velocities. Other non-disappearing C IV BALs in those nine objects having multiple troughs tend to weaken when one of them disappears, indicating a connection between the disappearing and non-disappearing troughs, even for velocity separations as large as 10,000-15,000 km s-1. We discuss possible origins of this connection including disk-wind rotation and changes in shielding gas.

Filiz Ak, N.; Brandt, W. N.; Hall, P. B.; Schneider, D. P.; Anderson, S. F.; Gibson, R. R.; Lundgren, B. F.; Myers, A. D.; Petitjean, P.; Ross, Nicholas P.; Shen, Yue; York, D. G.; Bizyaev, D.; Brinkmann, J.; Malanushenko, E.; Oravetz, D. J.; Pan, K.; Simmons, A. E.; Weaver, B. A.

2012-10-01

99

Properties of radio-detected broad absorption line quasars from the Sloan Digital Sky Survey  

NASA Astrophysics Data System (ADS)

We investigate the optical colors and radio morphologies of 214 broad absorption line (BAL) quasars with FIRST detections in the redshift range 1.68? z?4.93 drawn from the Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) quasar catalog. The radio-detected SDSS BAL quasars are found to have ?( g- i) colors significantly redder than their non-BAL counterparts, with a mean color difference of 0.52 mag, in good agreement with the O- E (roughly B- R) color difference between radio-selected BAL and non-BAL quasars in the FIRST Bright Quasar Survey (FBQS). The vast majority (˜90 %) of the radio-detected BAL quasars are found to be core-only sources, most of which show compact radio morphologies, consistent with the morphological results for the FBQS sample. Moreover, within the FIRST-detected SDSS sample, BAL quasars with GB6 detections are found to span a wide range in radio spectral indices, indistinguishable from that of non-BAL quasars, indicating no special line of sight for the presence of BALs. The properties of the present SDSS sample are more consistent with the evolutionary model, in which BALs are at an early evolutionary stage of quasars.

Pu, Xingting

2013-06-01

100

On the absorption of X-ray bright broad absorption line quasars  

NASA Astrophysics Data System (ADS)

Context: Most X-ray studies of broad absorption line quasars (BALQSOs) found significant (NH˜ 1022-24 cm-2) intrinsic column densities of gas absorbing an underlying typical power-law continuum emission, in agreement with expectations from radiatively driven accretion disk wind models. However, direct spectral analysis was performed only on a limited number of bright sources. Aims: We investigate the X-ray emission of a large number of BALQSOs at medium to high redshift (0.8? z ? 3.7) with the best data available to date. Methods: We drew a large BALQSO sample from the cross-correlation of SDSS DR5 and 2XMM catalogs to perform moderate-quality X-ray spectral and hardness ratio analysis and X-ray/optical photometry. We compare our results with previous studies of BALQSOs and theoretical disk wind model expectations. Results: No or little intrinsic X-ray neutral absorption is found for one third of the spectroscopically analyzed BALQSO sample (NH < 4 × 1021 cm-2 at 90% confidence level), and lower than typical X-ray absorption is found in the remaining sources (< NH> ˜ 5 × 1022 cm-2) even including the faintest sources analyzed through hardness ratio analysis. The mean photon index is ? ˜ 1.9, with no significant evolution with redshift. The optical/X-ray spectral indices ?ox are typical of radio-quiet broad line AGN, in contrast with the known (from previous X-ray studies) “soft X-ray weakness” of BALQSOs and in agreement with the lack of X-ray absorption. We found the low-absorption index (AI) subsample to host the lowest X-ray absorbing column densities of the entire sample. Conclusions: X-ray selected BALQSOs show lower X-ray absorption than purely optically selected ones, and soft X-ray weakness does not hold for any of them. Their outflows may be launched by different mechanisms than classical soft X-ray weak BALQSOs or they may be the tail of the already known population seen along a different line of sight, in both cases expanding the observational parameter space for their search and investigation. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. Appendices A and B are only available in electronic form at http://www.aanda.org

Giustini, M.; Cappi, M.; Vignali, C.

2008-11-01

101

A Census of Broad-line Active Galactic Nuclei in Nearby Galaxies: Coeval Star Formation and Rapid Black Hole Growth  

NASA Astrophysics Data System (ADS)

We present the first quantified, statistical map of broad-line active galactic nucleus (AGN) frequency with host galaxy color and stellar mass in nearby (0.01 < z < 0.11) galaxies. Aperture photometry and z-band concentration measurements from the Sloan Digital Sky Survey are used to disentangle AGN and galaxy emission, resulting in estimates of uncontaminated galaxy rest-frame color, luminosity, and stellar mass. Broad-line AGNs are distributed throughout the blue cloud and green valley at a given stellar mass, and are much rarer in quiescent (red sequence) galaxies. This is in contrast to the published host galaxy properties of weaker narrow-line AGNs, indicating that broad-line AGNs occur during a different phase in galaxy evolution. More luminous broad-line AGNs have bluer host galaxies, even at fixed mass, suggesting that the same processes that fuel nuclear activity also efficiently form stars. The data favor processes that simultaneously fuel both star formation activity and rapid supermassive black hole accretion. If AGNs cause feedback on their host galaxies in the nearby universe, the evidence of galaxy-wide quenching must be delayed until after the broad-line AGN phase.

Trump, Jonathan R.; Hsu, Alexander D.; Fang, Jerome J.; Faber, S. M.; Koo, David C.; Kocevski, Dale D.

2013-02-01

102

Stellar Contrails in Quasi-stellar Objects: The Origin of Broad Absorption Lines  

NASA Astrophysics Data System (ADS)

Active galactic nuclei (AGNs) and quasars often exhibit infrared excesses at ? = 2-10 microns attributable to thermal dust emission. In this paper we propose that this hot dust is supplied by circumstellar mass loss from evolved stars in the nuclear star cluster. The physics of the mass-loss dust, specifically the evaporation temperature, is a critical parameter in determining the accretion rate of mass-loss material onto the central AGN. For standard interstellar dust grains with an evaporation temperature of 1800 K the dust is destroyed inside a radius of 1 pc from a central luminosity source of 5 × 10 Lsun. The mass-loss material inside 1 pc will therefore have a lower radiation pressure efficiency and accrete inward. Outside this critical radius, dust may survive, and the mass loss is accelerated outward owing to the high radiation pressure efficiency of the dust mixed with the gas. The outflowing material will consist of discrete trails of debris shed by the individual mass-loss stars, and we suggest that these trails produce the broad absorption lines (BALs) seen in 5%-10% of QSOs. The model accounts naturally for the maximum outflow velocities seen in the BALs (˜30,000 km s-1 and varying as L¼) since this maximum terminal velocity occurs for matter originating at the inner edge of the radiative equilibrium dust survival zone. Although the radiation pressure acts on the dust, individual grains will be highly charged (Z ˜ 103+), and the grains are therefore strongly coupled to the gas through the ambient magnetic fields. Numerical hydrodynamic calculations were done to follow the evolution of mass-loss material. As the orbiting debris is driven outward by radiation pressure, the trail forms a spiral with initially high pitch angle (˜85°). The trails are compressed into thin ribbons in the radial direction initially by the radiation pressure gradients due to absorption within the trail. After reaching > 104 km s-1 radial velocity, the compression can be maintained by ram pressure due to an ambient gas of modest density (˜102 cm-3). Each of the stellar contrails will have mean column density ˜1019-1021 cm-2, volume density ˜108-109 cm-3, and thickness 1011-1012 cm along the line of sight to the AGN corresponding to parameters deduced from observations of the BAL clouds. Assuming minimal expansion perpendicular to the line of sight at the speed of sound, the width of the trails is 1015-1016 cm, or 102-103 times the line-of-sight depth. Since the UV-emitting accretion disk probably has a radius of about 2 × 1016 cm, a single trail will only partially cover the continuum, but for the column densities quoted above the observed absorption lines (e.g., C IV) will be optically thick with ? > 10. Since the contrails are nearly radial just after leaving the star when the maximum outward acceleration occurs, a large range of velocities (˜4000 km s-1) will be seen in absorption of the QSO light from each trail, and only a few disk-crossing trails are needed to account for the full width of broad absorption line troughs.

Scoville, Nick; Norman, Colin

1995-10-01

103

MULTIWAVELENGTH VARIABILITY OF THE BROAD LINE RADIO GALAXY 3C 120  

SciTech Connect

We present results from a multiyear monitoring campaign of the broad-line radio galaxy 3C 120, using the Rossi X-ray Timing Explorer for nearly five years of observations. Additionally, we present coincident optical monitoring using data from several ground-based observatories. Both the X-ray and optical emission are highly variable and appear to be strongly correlated, with the X-ray emission leading the optical by 28 days. The X-ray power density spectrum is best fit by a broken power law, with a low-frequency slope of -1.2, breaking to a high-frequency slope of -2.1, and a break frequency of log {nu}{sub b} = -5.75 Hz, or 6.5 days. This value agrees well with the value expected based on 3C 120's mass and accretion rate. We find no evidence for a second break in the power spectrum. Combined with a moderately soft X-ray spectrum ({gamma} = 1.8) and a moderately high accretion rate, this indicates that 3C 120 fits in well with the high/soft variability state found in most other active galactic nuclei. Previous studies have shown that the spectrum has a strong Fe K{alpha} line, which may be relativistically broadened. The presence of this line, combined with a power spectrum similar to that seen in Seyfert galaxies, suggests that the majority of the X-ray emission in this object arises in or near the disk, and not in the jet.

Marshall, Kevin [Department of Physics, Bucknell University, Lewisburg PA 17837 (United States); Ryle, Wesley T.; Miller, H. Richard [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States); Marscher, Alan P.; Jorstad, Svetlana G. [Institute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston MA 02215 (United States); Chicka, Benjamin [School of Theology, Boston University, 745 Commonwealth Ave., Boston, MA 02215 (United States); McHardy, Ian M. [School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom)], E-mail: kevin.marshall@bucknell.edu

2009-05-01

104

Broad-line Reverberation in the Kepler-field Seyfert Galaxy Zw 229-015  

NASA Astrophysics Data System (ADS)

The Seyfert 1 galaxy Zw 229-015 is among the brightest active galaxies being monitored by the Kepler mission. In order to determine the black hole mass in Zw 229-015 from H? reverberation mapping, we have carried out nightly observations with the Kast Spectrograph at the Lick 3 m telescope during the dark runs from 2010 June through December, obtaining 54 spectroscopic observations in total. We have also obtained nightly V-band imaging with the Katzman Automatic Imaging Telescope at Lick Observatory and with the 0.9 m telescope at the Brigham Young University West Mountain Observatory over the same period. We detect strong variability in the source, which exhibited more than a factor of two change in broad H? flux. From cross-correlation measurements, we find that the H? light curve has a rest-frame lag of 3.86+0.69 -0.90 days with respect to the V-band continuum variations. We also measure reverberation lags for H? and H? and find an upper limit to the H? lag. Combining the H? lag measurement with a broad H? width of ?line = 1590 ± 47 km s-1 measured from the rms variability spectrum, we obtain a virial estimate of M BH = 1.00+0.19 -0.24 × 107 M sun for the black hole in Zw 229-015. As a Kepler target, Zw 229-015 will eventually have one of the highest-quality optical light curves ever measured for any active galaxy, and the black hole mass determined from reverberation mapping will serve as a benchmark for testing relationships between black hole mass and continuum variability characteristics in active galactic nuclei.

Barth, Aaron J.; Nguyen, My L.; Malkan, Matthew A.; Filippenko, Alexei V.; Li, Weidong; Gorjian, Varoujan; Joner, Michael D.; Bennert, Vardha Nicola; Botyanszki, Janos; Cenko, S. Bradley; Childress, Michael; Choi, Jieun; Comerford, Julia M.; Cucciara, Antonino; da Silva, Robert; Duchêne, Gaspard; Fumagalli, Michele; Ganeshalingam, Mohan; Gates, Elinor L.; Gerke, Brian F.; Griffith, Christopher V.; Harris, Chelsea; Hintz, Eric G.; Hsiao, Eric; Kandrashoff, Michael T.; Keel, William C.; Kirkman, David; Kleiser, Io K. W.; Laney, C. David; Lee, Jeffrey; Lopez, Liliana; Lowe, Thomas B.; Moody, J. Ward; Morton, Alekzandir; Nierenberg, A. M.; Nugent, Peter; Pancoast, Anna; Rex, Jacob; Rich, R. Michael; Silverman, Jeffrey M.; Smith, Graeme H.; Sonnenfeld, Alessandro; Suzuki, Nao; Tytler, David; Walsh, Jonelle L.; Woo, Jong-Hak; Yang, Yizhe; Zeisse, Carl

2011-05-01

105

Differences between the two types Seyfert 2 galaxies - With and without polarized broad lines  

NASA Astrophysics Data System (ADS)

Based on spectropolarimetric observations Seyfert 2 (Sy2) galaxies are generally divided into two populations. Some Sy2s show polarized broad emission lines (PBLs) which is an evidence for the hypothesis of the Unified model while others do not. In order to determine the properties of these two apparently different populations we compiled a sample of 66 Sy2 objects with and without detected PBLs. We used a ( J - H) - ( H - Ks) diagram based on 2MASS J, H, Ks magnitudes in 14 arcsec aperture, the F[OIII] emission line flux and the infrared emission flux F using the Ks filter. From the ( J - H) - ( H - Ks) diagram we determined that one third of the Sy2 objects with PBLs have a power-law infrared component which could be a result of both a non-thermal AGN component scattered by free electrons (or dust) and emission from hot dust near its sublimation temperature. The rest of the objects (with PBLs) are significantly dominated by a dust thermal re-emission. The Sy2s without PBLs show infrared emission dominated by a host galaxy stellar component and also by thermal dust re-emission. The Sy2s with PBLs tend to have a few times larger L[OIII] luminosities than those without. Following the median values of F/F, it seems that this ratio is sensitive enough to separate our sample of Sy2 galaxies into two types - with and without PBLs. There are no Sy2s with PBLs having Eddington ratio below 10 -3 which confirms the results of Nicastro et al. (2003).

Petrov, G. P.; Yankulova, I. M.

2012-02-01

106

Broad Absorption Line Variability on Multi-year Timescales in a Large Quasar Sample  

NASA Astrophysics Data System (ADS)

We present a detailed investigation of the variability of 428 C IV and 235 Si IV broad absorption line (BAL) troughs identified in multi-epoch observations of 291 quasars by the Sloan Digital Sky Survey-I/II/III. These observations primarily sample rest-frame timescales of 1-3.7 yr over which significant rearrangement of the BAL wind is expected. We derive a number of observational results on, e.g., the frequency of BAL variability, the velocity range over which BAL variability occurs, the primary observed form of BAL-trough variability, the dependence of BAL variability upon timescale, the frequency of BAL strengthening versus weakening, correlations between BAL variability and BAL-trough profiles, relations between C IV and Si IV BAL variability, coordinated multi-trough variability, and BAL variations as a function of quasar properties. We assess implications of these observational results for quasar winds. Our results support models where most BAL absorption is formed within an order-of-magnitude of the wind-launching radius, although a significant minority of BAL troughs may arise on larger scales. We estimate an average lifetime for a BAL trough along our line-of-sight of a few thousand years. BAL disappearance and emergence events appear to be extremes of general BAL variability, rather than being qualitatively distinct phenomena. We derive the parameters of a random-walk model for BAL EW variability, finding that this model can acceptably describe some key aspects of EW variability. The coordinated trough variability of BAL quasars with multiple troughs suggests that changes in "shielding gas" may play a significant role in driving general BAL variability.

Filiz Ak, N.; Brandt, W. N.; Hall, P. B.; Schneider, D. P.; Anderson, S. F.; Hamann, F.; Lundgren, B. F.; Myers, Adam D.; Pâris, I.; Petitjean, P.; Ross, Nicholas P.; Shen, Yue; York, Don

2013-11-01

107

Human broadly neutralizing antibodies to the envelope glycoprotein complex of hepatitis C virus  

PubMed Central

Hepatitis C virus (HCV) infects ?2% of the world's population. It is estimated that there are more than 500,000 new infections annually in Egypt, the country with the highest HCV prevalence. An effective vaccine would help control this expanding global health burden. HCV is highly variable, and an effective vaccine should target conserved T- and B-cell epitopes of the virus. Conserved B-cell epitopes overlapping the CD81 receptor-binding site (CD81bs) on the E2 viral envelope glycoprotein have been reported previously and provide promising vaccine targets. In this study, we isolated 73 human mAbs recognizing five distinct antigenic regions on the virus envelope glycoprotein complex E1E2 from an HCV-immune phage-display antibody library by using an exhaustive-panning strategy. Many of these mAbs were broadly neutralizing. In particular, the mAb AR4A, recognizing a discontinuous epitope outside the CD81bs on the E1E2 complex, has an exceptionally broad neutralizing activity toward diverse HCV genotypes and protects against heterologous HCV challenge in a small animal model. The mAb panel will be useful for the design and development of vaccine candidates to elicit broadly neutralizing antibodies to HCV.

Giang, Erick; Dorner, Marcus; Prentoe, Jannick C.; Dreux, Marlene; Evans, Matthew J.; Bukh, Jens; Rice, Charles M.; Ploss, Alexander; Burton, Dennis R.; Law, Mansun

2012-01-01

108

Human broadly neutralizing antibodies to the envelope glycoprotein complex of hepatitis C virus.  

PubMed

Hepatitis C virus (HCV) infects ?2% of the world's population. It is estimated that there are more than 500,000 new infections annually in Egypt, the country with the highest HCV prevalence. An effective vaccine would help control this expanding global health burden. HCV is highly variable, and an effective vaccine should target conserved T- and B-cell epitopes of the virus. Conserved B-cell epitopes overlapping the CD81 receptor-binding site (CD81bs) on the E2 viral envelope glycoprotein have been reported previously and provide promising vaccine targets. In this study, we isolated 73 human mAbs recognizing five distinct antigenic regions on the virus envelope glycoprotein complex E1E2 from an HCV-immune phage-display antibody library by using an exhaustive-panning strategy. Many of these mAbs were broadly neutralizing. In particular, the mAb AR4A, recognizing a discontinuous epitope outside the CD81bs on the E1E2 complex, has an exceptionally broad neutralizing activity toward diverse HCV genotypes and protects against heterologous HCV challenge in a small animal model. The mAb panel will be useful for the design and development of vaccine candidates to elicit broadly neutralizing antibodies to HCV. PMID:22492964

Giang, Erick; Dorner, Marcus; Prentoe, Jannick C; Dreux, Marlène; Evans, Matthew J; Bukh, Jens; Rice, Charles M; Ploss, Alexander; Burton, Dennis R; Law, Mansun

2012-04-04

109

Broad Absorption Line Variability on Multi-Year Timescales: Current Results and SDSS-III Prospects  

NASA Astrophysics Data System (ADS)

Over the past few years, studies of the variability of quasar Broad Absorption Lines (BALs) on multi-year rest-frame timescales have provided a number of intriguing results. These include (1) quantification of how BAL variability increases with rest-frame timescale, (2) characterization of the basic modes of multi-year BAL variability; e.g., variation often occurs in discrete regions which are only a few thousand km/s wide, and (3) tight limits upon BAL acceleration enabled by the long sampled timescales. We are aiming to transform the field of multi-year BAL variability studies into one that supplies rigorous large-sample constraints upon quasar winds using an ancillary project of the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). BOSS is re-observing 2000 bright BAL quasars originally observed by SDSS-I/SDSS-II from 2000-2008. This sample size is 100 times larger than those of current multi-year BAL variability studies, and > 800 objects are already observed. Measured variations constrain, e.g., BAL disappearance and emergence, BAL lifetimes, the modes of multi-year BAL variability, and BAL acceleration. For example, we have already detected about 20 new examples of BAL disappearance events. Soon we will constrain the dependence of multi-year BAL variability upon luminosity, redshift, black-hole mass, Eddington fraction, and radio properties.

Niel Brandt, W.; Filiz Ak, N.; Hall, P. B.; Schneider, D. P.; BOSS Quasar Working Group

2012-05-01

110

The Long-term X-ray Variability Of Broad Absorption Line Quasars  

NASA Astrophysics Data System (ADS)

We analyze X-ray the variability of eleven broad absorption line (BAL) quasars. This sample has coverage with multiple X-ray observations including Chandra, XMM-Newton , BeppoSAX , ASCA, ROSAT , and Einstein. In seven out of the eleven sources we have analyzed new short Chandra observations (5-7 ks) suitable for searching for any strong X-ray variability. Our X-ray coverage on each source spans approximately six X-ray observations with a rest-frame time of 13.7 years. We find evidence of X-ray variability (with significance >99%) in three sources (PG 1001+054, PG 1004+130, and PG 2112+059). The flux amplitude of the variability is 3.3 ± 1.2, 1.50 ± 0.06, and 10.8 ± 2.6 with rest-frame times scales of approximately 5.8, 1.4, and 0.5 years for PG 1001+054, PG 1004+130, and PG 2112+059 respectively. For PG 1004+130 and PG 2112+059 we also find significant (with significance >99%) spectral X-ray variability associated to their flux variability. Additionally, we report for the first time an X-ray detection of IRAS 14026+4341 with statistical significance of ?5? in its new Chandra observation.

Saez, Cristian; Brandt, N.; Gallagher, S.; Bauer, F.; Garmire, G.

2012-05-01

111

Jet-linked X-ray emission in radio-loud broad absorption line (BAL) quasars  

NASA Astrophysics Data System (ADS)

We have applied theoretical models to explain spectral energy distribution (SED) of three radio-loud broad absorption line (BAL) quasars: an extended hybrid object PG 1004+130 and two compact sources 1045+352 and 3C270.1. We calculate the emission from the very inner part of the sources which accounts for more than 90% of the observed X-ray radiation. In our analysis we consider a scenario in which the observed X-ray emission comes from the inverse-Compton (IC) scattering inside a jet and from the accretion disk corona. The compact objects 1045+352 and 3C270.1 are high-redshift quasars (z = 1.604 and 1.532 respectively), with strong radio cores. We argue that in the case of these two sources a non-thermal, inverse-Compton emission from the innermost parts of the jet can explain a large fraction of the observed X-ray emission. The large scale object PG 1004+130 with a peculiar radio morphology is a low-redshift (z = 0.24), lobe-dominated BAL quasar with a weak radio core. In this case simulated inverse-Compton X-ray emission of the jet is relatively low. However, the corona emission appears strong enough to explain the observed X-ray spectrum of this object.

Kunert-Bajraszewska, M.; Katarzy?ski, K.; Janiuk, A.; Ceg?owski, M.

2013-02-01

112

A Very Large Array Survey of Radio-selected SDSS Broad Absorption Line Quasars  

NASA Astrophysics Data System (ADS)

We have built a sample of 74 radio-selected broad absorption line (BAL) quasars from the Sloan Digital Sky Survey Data Release 5 and Faint Images of the Radio Sky at Twenty Centimeters, along with a well-matched sample of 74 unabsorbed "normal" quasars. The sources have been observed with the NRAO Very Large Array/Expanded Very Large Array at 8.4 GHz (3.5 cm) and 4.9 GHz (6 cm). All sources have additional archival 1.4 GHz (21 cm) data. Here we present the measured radio fluxes, spectral indices, and our initial findings. The percentage of BAL quasars with extended structure (on the order of 10%) in our sample is similar to previous studies at similar resolutions, suggesting that BAL quasars are indeed generally compact, at least at arsecond resolutions. The majority of sources do not appear to be significantly variable at 1.4 GHz, but we find two previously unidentified BAL quasars that may fit into the "polar" BAL category. We also identify a significant favoring of steeper radio spectral index for BAL compared to non-BAL quasars. This difference is apparent for several different measures of the spectral index and persists even when restricting the samples to only include compact objects. Because radio spectral index is a statistical indicator of viewing angle for large samples, these results suggest that BAL quasars do have a range of orientations but are more often observed farther from the jet axis compared to normal quasars.

DiPompeo, M. A.; Brotherton, M. S.; De Breuck, C.; Laurent-Muehleisen, Sally

2011-12-01

113

Stability of cloud orbits in the broad-line region of active galactic nuclei  

NASA Astrophysics Data System (ADS)

We investigate the global dynamic stability of spherical clouds in the broad-line region (BLR) of active galactic nuclei (AGN), exposed to radial radiation pressure, gravity of the central black hole (BH) and centrifugal forces assuming the clouds adapt their size according to the local pressure. We consider both isotropic and anisotropic light sources. In both cases, stable orbits exist also for very sub-Keplerian rotation for which the radiation pressure contributes substantially to the force budget. We demonstrate that highly eccentric, very sub-Keplerian stable orbits may be found. This gives further support for the model of Marconi et al., who pointed out that BH masses might be significantly underestimated if radiation pressure is neglected. That model improved the agreement between BH masses derived in certain active galaxies based on BLR dynamics, and BH masses derived by other means in other galaxies by inclusion of a luminosity-dependent term. For anisotropic illumination, energy is conserved for averages over long time intervals only, but not for individual orbits. This leads to Rosetta orbits that are systematically less extended in the direction of maximum radiation force. Initially isotropic relatively low column density systems would therefore turn into a disc when an anisotropic AGN is switched on.

Krause, Martin; Burkert, Andreas; Schartmann, Marc

2011-02-01

114

Niobium oxide acidity studied by proton broad-line NMR at 4 K and MAS NMR at room temperature  

Microsoft Academic Search

The quantitative study of the Brønsted acidity of niobic acid (Nb2O5·xH2O) using broad-line1H NMR at 4 K has been performed by interacting niobic acid, pretreated at 573 K under vacuum, with water molecules. The number of oxyprotonated species (H3O+ and H2O...HO species formed, unreacted acidic OH groups or excess H2O molecules) deduced from the simulations of the broad-line1H NMR spectra

Patrice Batamack; Robert Vincent; Jacques Fraissard

1996-01-01

115

The Nature of Low-ionization Broad Absorption Line Quasi-stellar Objects  

NASA Astrophysics Data System (ADS)

The tight correlations between properties of galaxy bulges and their central supermassive black holes have been reproduced successfully in simulations of galaxy collisions if feedback processes are invoked. Mergers of gas-rich galaxies of comparable size have been shown to trigger starbursts, fuel the central black holes, and transform disks into ellipticals. Feedback from the black hole accretion in the form of extreme outflows has need suggested as the mechanism by which the black hole stop its own growth and quenches the star formation in the galaxy by expelling the gas supply. Such winds have been detected in Broad Absorption Line (BAL) QSOs. However, observational evidence that BAL QSOs may be an evolutionary link between mergers and QSO is missing. In this thesis, we provide the first detailed study of the spectral energy distributions and host galaxy morphologies of a statistically significant volume-limited sample of 22 optically-selected low-ionization Broad Absorption Line QSOs (LoBALs) at 0.5 < z < 0.6. By comparing their mid-IR spectral properties and far-IR SEDs with those of a control sample of 35 non-LoBALs (non-LoBALs) matched in Mi, we investigate the differences between the two populations in terms of their infrared emission and star formation activity. We model the SEDs and decouple the AGN and starburst contributions to the far-infrared luminosity in LoBALs and in non-LoBALs. We estimate star formation rates (SFRs) corrected for the AGN contribution to the FIR flux and find that LoBALs have comparable levels of star formation activity to non-LoBALs when considering the entire samples. Overall, our results show that there is no strong evidence from the mid- and far-IR properties that LoBALs are drawn from a different parent population than non-LoBALs. We conducted the first high-resolution morphological analysis of LoBALs using observations obtained with the Hubble Space Telescope Wide Field Camera 3 in two channels. Signs of recent or ongoing tidal interaction are seen in 59% of the host galaxies, including interacting companions, tidal tails, bridges, asymmetries, plumes, and boxy isophotes. The presence of a second nucleus within ~1" (6.4 kpc) is revealed in seven of the systems. A detailed two-dimensional surface brightness analysis with GALFIT indicates that the majority (73%) have prominent early-type (bulge, n>4) morphology and only four systems have exponential disk profiles (n<2). Two of the disks and one bulge are better described as pseudobulges (n<2.2). The dominance of bulges and unambiguous signs of tidal interaction strongly suggests that the population LoBALs are QSOs that result from major mergers. Nevertheless, most of the merger-induced start formation is already quenched. This sample of LoBALs represents merger systems at various stages of the interaction process, hence, either the outflows which characterize these systems persist for as long as the interaction signs are observable in the galaxy, or very short-lived outflows are triggered and die out during various stages of the merger process. Overall, our results are consistent with LoBALs representing the last stages of the blowout phase when QSO winds have already quenched the star formation.

Lazarova, Mariana Spasova

116

The Long-term X-Ray Variability of Broad Absorption Line Quasars  

NASA Astrophysics Data System (ADS)

We analyze the long-term (rest-frame 3-30 yr) X-ray variability of 11 broad absorption line (BAL) quasars, mainly to constrain the variation properties of the X-ray absorbing shielding gas that is thought to play a critical role in BAL wind launching. Our BAL quasar sample has coverage with multiple X-ray observatories including Chandra, XMM-Newton, BeppoSAX, ASCA, ROSAT, and Einstein; 3-11 observations are available for each source. For seven of the eleven sources we have obtained and analyzed new Chandra observations suitable for searching for any strong X-ray variability. We find highly significant X-ray variability in three sources (PG 1001+054, PG 1004+130, and PG 2112+059). The maximum observed amplitude of the 2-8 keV variability is a factor of 3.8 ± 1.3, 1.5 ± 0.2, and 9.9 ± 2.3 for PG 1001+054, PG 1004+130, and PG 2112+059, respectively, and these sources show detectable variability on rest-frame timescales down to 5.8, 1.4, and 0.5 yr. For PG 1004+130 and PG 2112+059 we also find significant X-ray spectral variability associated with the flux variability. Considering our sample as a whole, we do not find that BAL quasars exhibit exceptional long-term X-ray variability when compared to the quasar population in general. We do not find evidence for common strong changes in the shielding gas owing to physical rearrangement or accretion-disk rotation, although some changes are found; this has implications for modeling observed ultraviolet BAL variability. Finally, we report for the first time an X-ray detection of the highly polarized and well-studied BAL quasar IRAS 14026+4341 in its new Chandra observation.

Saez, C.; Brandt, W. N.; Gallagher, S. C.; Bauer, F. E.; Garmire, G. P.

2012-11-01

117

Chandra X-Ray Observations of Radio-Loud Broad Absorption Line Quasars  

NASA Astrophysics Data System (ADS)

We report the results of a Chandra X-Ray Observatory survey of five formally radio-loud broad absorption line (BAL) quasars. These five objects include BAL quasars with a range of properties, including both high- and low-ionization BALs. All five BAL quasars are detected in 5 ks ACIS-S exposures, with counts ranging from 12 to 55. The X-ray count rates are down by factors of 40 or more compared to expectations based on the spectral energy distributions of normal, unabsorbed radio-loud quasars; this is the same sort of behavior seen in radio-quiet BAL quasars. Interestingly, the hardness ratios are rather soft and inconsistent with absorption from a neutral hydrogen column density large enough to suppress the X-rays as observed. We conclude that in many cases the X-rays emanating from BAL quasars must be reflected, scattered, or leaked through an ionized absorber or a neutral absorber that does not completely cover the X-ray source (covering >=98%), or that we are seeing an unabsorbed X-ray source perhaps associated with a radio jet. Much higher counts are required to distinguish among these possibilities. We note several suggestive correlations involving X-ray properties that require verification using larger samples. One source, FIRST J1556+3517, appears to be the X-ray brightest low-ionization BAL quasar known, other than the special case of the nearby Mrk 231. The very faint X-ray emission from FIRST J1044+3656 is consistent with significant obscuration, which strongly favors the multiphase X-ray shielding models of this object in the literature.

Brotherton, M. S.; Laurent-Muehleisen, S. A.; Becker, R. H.; Gregg, Michael D.; Telis, Gisela; White, R. L.; Shang, Zhaohui

2005-11-01

118

A novel composite right-\\/left-handed coupled-line directional coupler with arbitrary coupling level and broad bandwidth  

Microsoft Academic Search

A novel composite right-\\/left-handed (CRLH) backward-wave coupled-line directional coupler with arbitrary coupling level and broad bandwidth is presented, explained by even\\/odd-mode analysis, validated by full-wave simulations, and demonstrated by experiments. First, the CRLH-transmission-line (CRLH TL) theory is given, and a microstrip implementation of a CRLH TL is described. A simple circuit model is then proposed both for the understanding and

Christophe Caloz; Atsushi Sanada; Tatsuo Itoh

2004-01-01

119

SN 2010ay is a Luminous and Broad-lined Type Ic Supernova within a Low-metallicity Host Galaxy.  

National Technical Information Service (NTIS)

We report on our serendipitous pre-discovery detection and detailed follow-up of the broad-lined Type Ic supernova SN2010ay at z approx 0.067 imaged by the Pan-STARRS1 3pi survey just approx 4 days after explosion. Combining our photometric observations w...

A. Von Kienlin A. M. Soderberg E. Berger E. Mazets E. M. Levesque G. Narayan J. N. Heasley K. Hurley K. C. Chambers L. Chomiuk M. S. Briggs M. T. Botticella N. Gehrels N. E. Sanders R. Chornock R. J. Foley S. Golenetskii S. Smartt S. Valenti S. D. Barthelmy T. Cline T. Grav V. Connaughton W. Boynton Y. Terada

2011-01-01

120

Complex magnetically insulated transmission line oscillator  

NASA Astrophysics Data System (ADS)

A magnetically insulated transmission line oscillator (MILO) is a crossed-field device designed specifically to generate microwave power at the gigawatt level, which is a major hotspot in the field of high-power microwaves (HPM) research at present. It is one of the major thrust for MILO development to improve the power conversion efficiency. In order to improve the power conversion efficiency of MILO, a complex MILO is presented and investigated theoretically and numerically, which comprises the MILO-1 and MILO-2. The MILO-2 is used as the load of the MILO-1. The theoretical analyses show that the maximum power conversion efficiency of the complex MILO has an increase of about 50% over the conventional load-limited MILO. The complex MILO is optimized with KARAT code (V. P. Tarakanov, Berkeley Research Associates, Inc., 1992), and the simulation results agree with the theoretical results.

Fan, Yu-Wei; Zhong, Hui-Huang; Shu, Ting; Li, Zhi-Qiang

2008-08-01

121

Complex magnetically insulated transmission line oscillator  

SciTech Connect

A magnetically insulated transmission line oscillator (MILO) is a crossed-field device designed specifically to generate microwave power at the gigawatt level, which is a major hotspot in the field of high-power microwaves (HPM) research at present. It is one of the major thrust for MILO development to improve the power conversion efficiency. In order to improve the power conversion efficiency of MILO, a complex MILO is presented and investigated theoretically and numerically, which comprises the MILO-1 and MILO-2. The MILO-2 is used as the load of the MILO-1. The theoretical analyses show that the maximum power conversion efficiency of the complex MILO has an increase of about 50% over the conventional load-limited MILO. The complex MILO is optimized with KARAT code (V. P. Tarakanov, Berkeley Research Associates, Inc., 1992), and the simulation results agree with the theoretical results.

Fan Yuwei; Zhong Huihuang; Shu Ting; Li Zhiqiang [College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

2008-08-15

122

Dependence of the Broad Absorption Line Quasar Fraction on Radio Luminosity  

NASA Astrophysics Data System (ADS)

We find that the fraction of classical broad absorption line quasars (BALQSOs) among the FIRST radio sources in the Sloan Data Release 3, is 20.5+7.3-5.9% at the faintest radio powers detected (L1.4GHz~1032 erg s-1), and rapidly drops to <~8% at L1.4GHz~3×1033 erg s-1. Similarly, adopting the broader absorption index (AI) definition of Trump et al., we find the fraction of radio BALQSOs to be 44+8.1-7.8%, reducing to 23.1+7.3-6.1% at high luminosities. While the high fraction at low radio power is consistent with the recent near-IR estimates by Dai et al., the lower fraction at high radio powers is intriguing and confirms previous claims based on smaller samples. The trend is independent of the redshift range, the optical and radio flux selection limits, or the exact definition of a radio match. We also find that at fixed optical magnitude, the highest bins of radio luminosity are preferentially populated by non-BALQSOs, consistent with the overall trend. We do find, however, that those quasars identified as AI-BALQSOs but not under the classical definition do not show a significant drop in their fraction as a function of radio power, further supporting independent claims that these sources, characterized by lower equivalent width, may represent an independent class from the classical BALQSOs. We find the balnicity index, a measure of the absorption trough in BALQSOs, and the mean maximum wind velocity to be roughly constant at all radio powers. We discuss several plausible physical models which may explain the observed fast drop in the fraction of the classical BALQSOs with increasing radio power, although none is entirely satisfactory. A strictly evolutionary model for the BALQSO and radio emission phases requires a strong fine-tuning to work, while a simple geometric model, although still not capable of explaining polar BALQSOs and the paucity of FRII BALQSOs, is statistically successful in matching the data if part of the apparent radio luminosity function is due to beamed, non-BALQSOs.

Shankar, Francesco; Dai, Xinyu; Sivakoff, Gregory R.

2008-11-01

123

Complex anisotropy in the Australian lithosphere from shear-wave splitting in broad-band SKS records  

Microsoft Academic Search

Shear wave splitting of seismic core phases reveals complex azimuthal anisotropy in continental Australia. Using the broad band width of the seismograms, we demonstrate that differing SKS splitting phenomena are manifested at different frequencies.

G. Clitheroe; R. D. van der Hilst

1998-01-01

124

The Resolved Fe K alpha Line of the Broad-Line Radio Galaxy 3C 390.3 and Its Implications  

Microsoft Academic Search

We present the results of X-ray observations of the broad-line radio galaxy 3C 390.3 obtained with ASCA The 0.5-10 keV spectrum of the source is well described by a power-law model plus a component arising from Compton reflection and an emission line. There is no evidence for a soft excess. The photon index is 1.70 + 0.04, and the absorbing

Michael Eracleous; Jules P. Halpern; Mario Livio

1996-01-01

125

OPTICAL EMISSION-LINE PROPERTIES OF A SAMPLE OF THE BROAD-LINE ACTIVE GALACTIC NUCLEI: THE BALDWIN EFFECT AND EIGENVECTOR 1  

SciTech Connect

We divide a sample of 302 type-1 active galactic nuclei into two subsamples based on the narrow-line [O III]/H{beta}{sub NLR} ratio, expecting that there will be a stronger starburst (H II region) contribution to the narrow-line emission for R = log([O III]/H{beta}{sub NLR}) < 0.5. For both samples, we find significant differences in correlations between spectral properties of objects with R < 0.5 and R > 0.5. We find similar differences when we divide the sample based on the FWHM ratios of [O III] and broad H{beta} lines (R{sub 1} = log (FWHM [O III]/FWHM H{beta}{sub broad}){sup >} {sub <} - 0.8), i.e., similar correlations between R > 0.5 and R{sub 1} < -0.8 subsamples from one side and R < 0.5 and R{sub 1} > -0.8 subsamples from the other side. The most interesting difference is in the correlation between the broad H{beta} FWHM and luminosity in the R < 0.5 (R{sub 1} > -0.8) sample, which indicates a connection between the broad-line region kinematics and the photoionization source. We discuss possible effects that can cause these differences in spectral properties of two subsamples.

Popovic, Luka C.; Kovacevic, Jelena, E-mail: lpopovic@aob.bg.ac.rs, E-mail: jkovacevic@aob.bg.ac.rs [Group for Astrophysical Spectroscopy, Astronomical Observatory, Volgina 7, 11060 Belgrade (Serbia)

2011-09-01

126

Broad-band microwave characterization of liquid crystals using a temperature-controlled coaxial transmission line  

Microsoft Academic Search

Liquid crystals (LCs) promise to be suitable passive tunable material for microwave devices with excellent features concerning tunability and losses. In order to optimize the synthesis of LCs and the design of tunable microwave devices based on them, LCs have to be characterized at microwaves. For a microwave analysis between 360 MHz-23 GHz, use was made of a broad-band characterization

Stefan Mueller; Andreas Penirschke; Christian Damm; Patrick Scheele; Michael Wittek; Carsten Weil; Rolf Jakoby

2005-01-01

127

Broad-Band Coplanar Waveguide to Slot Line Transition. (Reannouncement with New Availability Information).  

National Technical Information Service (NTIS)

A novel approach for designing a broad-band coplanar waveguide (CPW) to slotline transition is presented. A slotline hollow patch creates open circuit conditions on one arm of the CPW and resonates the transition so that maximum power transfer may occur. ...

T. Q. Ho S. M. Hart

1992-01-01

128

Broad-band uniplanar hybrid-ring and branch-line couplers  

Microsoft Academic Search

Novel uniplanar 180° and 190° hybrids suitable for MIC and MMIC applications are described. The uniplanar crossover hybrid-ring coupler using a coplanar waveguide (CPW) and slotline provides substantially improved amplitude and phase characteristics over a broad bandwidth compared to conventional microstrip hybrid-ring couplers. Experimental results show that the new coupler has a bandwidth of more than one octave from 2

Chien-Hsun Ho; Lu Fan; Kai Chang

1993-01-01

129

An additional broad line region in 3C 390.3 associated with the jet  

NASA Astrophysics Data System (ADS)

We suggest the existence of two BLRs in 3C 390.3 which have different locations. The BLR1 is located at a distance in accordance to the hydrogen line time lags of ~20 days. This disk-like region emits predominantly low ionization lines. The BLR2 forms around the radio-jet and is located at the distance corresponding to time lags of ~ 40-80 days. The BLR2 is responsible for most of the emission in UV lines. The L? line partly forms in BLR2 (40-60%) and partly in BLR1.

Nazarova, L. S.; Bochkarev, N. G.

2011-02-01

130

Evidence for Nonlinear X-ray Variability from Broad-line Radio Galaxy 3C 390.3  

Microsoft Academic Search

We present analysis of the light curve from the ROSAT HRI monitoring observations of the broad-line radio galaxy 3C 390.3. Observed every three days for about 9 months, this is the first well sampled X-ray light curve on these time scales. The flares and quiescent periods in the light curve suggest that the variability is nonlinear, and a statistical test

K. M. Leighly; P. T. O'Brien

1996-01-01

131

CHANDRA HIGH-RESOLUTION SPECTROSCOPY OF THE CIRCUMNUCLEAR MATTER IN THE BROAD-LINE RADIO GALAXY 3C 445  

SciTech Connect

We present evidence for X-ray line emitting and absorbing gas in the nucleus of the broad-line radio galaxy 3C 445. A 200 ks Chandra Low Energy Transmission Grating observation of 3C 445 reveals the presence of several highly ionized emission lines in the soft X-ray spectrum, primarily from the He- and H-like ions of O, Ne, Mg, and Si. Radiative recombination emission is detected from O VII and O VIII, indicating that the emitting gas is photoionized. The He-like emission appears to be resolved into forbidden and intercombination line components, which implies a high density of >10{sup 10} cm{sup -3}, while the oxygen lines are velocity broadened with a mean width of {approx}2600 km s{sup -1} (FWHM). The density and widths of the ionized lines indicate an origin of the gas on sub-parsec scales in the broad-line region. The X-ray continuum of 3C 445 is heavily obscured either by a partial coverer or by a photoionized absorber of column density N{sub H} = 2 x 10{sup 23} cm{sup -2} and ionization parameter log {xi} = 1.4 erg cm s{sup -1}. However, the view of the X-ray line emission is unobscured, which requires the absorber to be located at radii well within any parsec-scale molecular torus. Instead we suggest that the X-ray absorber in 3C 445 may be associated with an outflowing but clumpy accretion disk wind, with an observed outflow velocity of {approx}10, 000 km s{sup -1}.

Reeves, J. N.; Gofford, J. [Astrophysics Group, School of Physical and Geographical Sciences, Keele University, Keele ST5 5BG (United Kingdom); Braito, V. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Sambruna, R., E-mail: jnr@astro.keele.ac.u [Code 662, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2010-12-10

132

Broad iron emission lines in Seyfert galaxies - re-condensation of gas onto an inner disk below the ADAF?  

NASA Astrophysics Data System (ADS)

Context. The number of strong iron K? line detections in Seyfert AGN is clearly growing in the Chandra, XMM-Newton and Suzaku era. The iron emission lines are broad, some are relativistically blurred. These relativistic disk lines have also been observed for galactic black hole X-ray binaries. Thermal components found in hard spectra were interpreted as an indication for a weak inner cool accretion disk underneath a hot corona. Aims: Accretion in low-mass X-ray binaries (LMXB) occurs during phases of high and low mass accretion rate, outburst and quiescence, soft and hard spectral state, respectively. After the soft/hard transition for some sources a thermal component is found, which can be interpreted as sustained by re-condensation of gas from an advection-dominated flow (ADAF) onto the disk. In view of the similarity of accretion flows around stellar mass and supermassive black holes we discuss whether the broad iron emission lines in Seyfert 1 AGN (active galactic nuclei) can be understood as arising from a similar accretion flow geometry as in X-ray binaries. Methods: We derive accretion rates for those Seyfert galaxies for which broad iron emission lines were observed, the "best candidates" in the investigations of Miller (2007, ARA&A, 45, 441) and Nandra et al. (2007, MNRAS, 382, 194). For the evaluation of the Eddington-scaled rates we use the observed X-ray luminosity, bolometric corrections and black hole masses from the literature. Results: The accretion rates derived for the Seyfert galaxies in our sample are less than 0.1 of the Eddington rate for more than half of the sources. For 107 to 108M? black holes in Seyfert 1 AGN this limit corresponds to 0.01 to 0.2 M?/yr. This documents that the sources probably are in a hard spectral state and iron emission lines can arise from an inner weak accretion disk surrounded by an ADAF as predicted by the re-condensation model. Some of the remaining sources with higher accretion rates may be in a spectral state that is comparable to the "very high" state of LMXBs. Conclusions: Our investigation shows that in quite a number of Seyfert AGN the broad iron emission lines may indeed originate in a weak inner disk below the ADAF, close to the black hole, indicating the same accretion flow geometry as recently found for LMXBs. For the accretion history one then concludes that the accretion rates were higher in the outer radii at some earlier time.

Meyer-Hofmeister, E.; Meyer, F.

2011-03-01

133

Constraints on Outflow Properties From Mg II in the Broad Absorption-Line Quasar FBQS J1151+3822  

NASA Astrophysics Data System (ADS)

The acceleration mechanism behind quasar outflows is as yet unknown, but constraining the kinetic energy invested in these winds should allow us to discriminate between competing models of their source. To that end, we use new observations of broad absorption-line Mg II in the quasar FBQS J1151+3822 to calculate Mg+ column density in the outflow. The Mg II apparent optical depth profile bears structural similarities to that of He I*?10830, suggesting that both lines are produced by the same outflow. Broad Fe II absorption around 2600 Å and blueward reveals that the quasar is an Fe Lo-BAL, and we infer significant iron blending in the high-velocity region of the Mg II line. To account for this blending, we operate under the assumption that the Mg II profile structure approximately mimics that of He I*?10830, and calculate that Mg+ column density has a lower limit at 1015.0 cm-2. Leighly et al. (2011) used the He I* lines at 10830 and 3889 Å to place broad constraints on the properties of the absorbing gas. Mg II allows us to significantly tighten these constraints; log ionization parameter is now restricted to between -1.4 and -1.3. We furthermore restrict ourselves to a scenario wherein density is between 107 and 108 cm-3, as justified by Leighly et al. via a dynamical argument and upper limits on Balmer absorption. These preliminary first order approximations constrain kinetic luminosity to between 1044 and 1044.5 ergs/s, absorption-line radius to between 5 and 18 pc, the ratio of kinetic to bolometric luminosity to between 0.2% and 0.6%, mass flux to between 11 and 34 M?/yr, and total hydrogen column density to between 1021.7 and 1021.9 cm-2. This work is funded by NSF AST-0707703.

Lucy, Adrian B.; Leighly, K. M.; Terndrup, D. M.; Dietrich, M.; Gallagher, S. C.

2012-01-01

134

Design of Simple Broad-Band Wave-Guide-to-Coaxial-Line Junctions  

Microsoft Academic Search

A wave-guide-to-coaxial-line junction having a better than 2-to-1 bandwidth with less than 2-to-1 voltage-standing-wave ratio was required in the design of microwave filters and receiver transmission systems. Several types of junctions satisfying these requirements were designed using simple transmission-line theory. One type designed for a standard wave-guide cross section has a bandwidth ratio of 2.7 to 1. The design method

S. B. Cohn

1947-01-01

135

Ripple effects and oscillations in the broad Fe K? line as a probe of massive black hole mergers  

NASA Astrophysics Data System (ADS)

When a sufficiently massive satellite (or secondary) black hole is embedded in a gas disc around a (primary) supermassive black hole, it can open an empty gap in the disc. A gap-opening secondary close to the primary will leave an imprint in the broad component of the Fe K? emission line, which varies in a unique and predictable manner. If the gap persists into the innermost disc, the effect consists of a pair of dips in the broad line which ripple blue-ward and red-ward from the line centroid energy, respectively, as the gap moves closer to the primary. This ripple effect could be unambiguously detectable and allow an electromagnetic monitoring of massive black hole mergers as they occur. As the mass ratio of the secondary to primary black hole increases to q ? 0.01, we expect the gap to widen, possibly clearing a central cavity in the inner disc, which shows up in the broad Fe K? line component. If the secondary stalls at ? 102rg in its in-migration, due to low corotating gas mass, a detectable ripple effect occurs in the broad line component on the disc viscous time-scale as the inner disc drains and the outer disc is dammed. If the secondary maintains an accretion disc within a central cavity, due to dam bursting or leakage, a periodic `see-saw' oscillation effect is exhibited in the observed line profile. Here, we demonstrate the range of ripple effect signatures potentially detectable with Astro-H and IXO/Athena, and oscillation effects potentially detectable with XMM-Newton or LOFT for a wide variety of merger and disc conditions, including gap width (or cavity size), disc inclination angle and emissivity profile, damming of the accretion flow by the secondary, and a minidisc around the satellite black hole. A systematic study of ripple effects would require a telescope effective area substantially larger than that planned for IXO/Athena. Future mission planning should take this into account. Observations of the ripple effect and periodic oscillations can be used to provide an early warning of gravitational radiation emission from the AGN. Once gravitational waves consistent with massive black hole mergers are detected, an archival search for the Fe K? ripple effect or periodic oscillations will help in localizing their origin.

McKernan, B.; Ford, K. E. S.; Kocsis, B.; Haiman, Z.

2013-06-01

136

Final report: A Broad Research Project in the Sciences of Complexity  

SciTech Connect

Previous DOE support for ''A Broad Research Program in the Sciences of Complexity'' permitted the Santa Fe Institute to initiate new collaborative research within its Integrative Core activities as well as to host visitors to participate in research on specific topics that serve as motivation and testing-ground for the study of general principles of complex systems. The critical aspect of this support is its effectiveness in seeding new areas of research. Indeed, this Integrative Core has been the birthplace of dozens of projects that later became more specifically focused and then won direct grant support independent of the core grants. But at early stages most of this multidisciplinary research was unable to win grant support as individual projects--both because it did not match well with existing grant program guidelines, and because the amount of handing needed was often too modest to justify a formal proposal to an agency. In fact, one of the attributes of core support has been that it permitted SFI to encourage high-risk activities because the cost was quite low. What is significant is how many of those initial efforts have been productive in the SFI environment. Many of SFI'S current research foci began with a short visit from a researcher new to the SFI community, or as small working groups that brought together carefully selected experts from a variety of fields. As mentioned above, many of the ensuing research projects are now being supported by other funding agencies or private foundations. Some of these successes are described.

None

2000-02-01

137

Sharp-Line and Broad-Continuum Radiation from Electrons Channeled in Diamond.  

National Technical Information Service (NTIS)

Measured energy spectra of photons emitted at 0 exp 0 by 54-MeV electron beam channeled along the most open planar directions of a 20 mu m thick diamond single crystal show unusually sharp lines which are identified as transitions between discrete states ...

M. Gouanere D. Sillou M. Spighel

1981-01-01

138

EXTREMELY BROAD RADIO RECOMBINATION MASER LINES TOWARD THE HIGH-VELOCITY IONIZED JET IN CEPHEUS A HW2  

SciTech Connect

We present the first detection of the H40{alpha}, H34{alpha}, and H31{alpha} radio recombination lines (RRLs) at millimeter wavelengths toward the high-velocity ionized jet in the Cepheus A HW2 star-forming region. From our single-dish and interferometric observations, we find that the measured RRLs show extremely broad asymmetric line profiles with zero-intensity line widths of {approx}1100 km s{sup -1}. From the line widths, we estimate a terminal velocity for the ionized gas in the jet of {>=}500 km s{sup -1}, consistent with that obtained from the proper motions of the HW2 radio jet. The total integrated line-to-continuum flux ratios of the H40{alpha}, H34{alpha}, and H31{alpha} lines are 43, 229, and 280 km s{sup -1}, clearly deviating from LTE predictions. These ratios are very similar to those observed for the RRL masers toward MWC349A, suggesting that the intensities of the RRLs toward HW2 are affected by maser emission. Our radiative transfer modeling of the RRLs shows that their asymmetric profiles could be explained by maser emission arising from a bi-conical radio jet with a semi-opening angle of 18 deg., electron density distribution varying as r {sup -2.11}, and turbulent and expanding wind velocities of 60 and 500 km s{sup -1}.

Jimenez-Serra, I.; Patel, N. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Martin-Pintado, J.; Baez-Rubio, A. [Centro de Astrobiologia (CSIC/INTA), Ctra. de Torrejon a Ajalvir km 4, E-28850 Torrejon de Ardoz, Madrid (Spain); Thum, C., E-mail: ijimenez-serra@cfa.harvard.edu, E-mail: npatel@cfa.harvard.edu, E-mail: jmartin@cab.inta-csic.es, E-mail: baezra@cab.inta-csic.es, E-mail: thum@iram.fr [Institut de Radio Astronomie Millimetrique, 300 Rue de la Piscine, F-38406 St. Martin d'Heres (France)

2011-05-10

139

High Genetic Variability of Herbivore-Induced Volatile Emission within a Broad Range of Maize Inbred Lines1  

PubMed Central

Maize plants (Zea mays) attacked by caterpillars release a mixture of odorous compounds that attract parasitic wasps, natural enemies of the herbivores. We assessed the genetic variability of these induced volatile emissions among 31 maize inbred lines representing a broad range of genetic diversity used by breeders in Europe and North America. Odors were collected from young plants that had been induced by injecting them with caterpillar regurgitant. Significant variation among lines was found for all 23 volatile compounds included in the analysis: the lines differed enormously in the total amount of volatiles emitted and showed highly variable odor profiles distinctive of each genotype. Principal component analysis performed on the relative quantities of particular compounds within the blend revealed clusters of highly correlated volatiles, which may share common metabolic pathways. European and American lines belonging to established heterotic groups were loosely separated from each other, with the most clear-cut difference in the typical release of (E)-?-caryophyllene by European lines. There was no correlation between the distances among the lines based on their odor profiles and their respective genetic distances previously assessed by neutral RFLP markers. This most comprehensive study to date on intraspecific variation in induced odor emission by maize plants provides a further example of the remarkably high genetic diversity conserved within this important crop plant. A better understanding of the genetic control of induced odor emissions may help in the development of maize varieties particularly attractive to parasitoids and other biological control agents and perhaps more repellent for herbivores.

Degen, Thomas; Dillmann, Christine; Marion-Poll, Frederic; Turlings, Ted C.J.

2004-01-01

140

SUZAKU OBSERVATION OF THE BRIGHTEST BROAD-LINE RADIO GALAXY 4C 50.55 (IGR J21247+5058)  

SciTech Connect

We report the results from a deep Suzaku observation of 4C 50.55 (IGR J21247+5058), the brightest broad-line radio galaxy in the hard X-ray (>10 keV) sky. The simultaneous broadband spectra over 1-60 keV can be represented by a cutoff power law with two layers of absorption and a significant reflection component from cold matter with a solid angle of {Omega}/2{pi} {approx} 0.2. A rapid flux rise by {approx}20% over 2 x 10{sup 4} s is detected in the 2-10 keV band. The spectral energy distribution suggests that there is little contribution to the total X-ray emission from jets. Applying a thermal Comptonization model, we find that corona is optically thick ({tau}{sub e} {approx} 3) and has a relatively low temperature (kT{sub e} {approx} 30 keV). The narrow iron-K emission line is consistent with a picture where the standard disk is truncated and/or its inner part is covered by optically thick Comptonizing corona smearing out relativistic broad-line features. The inferred disk structure may be a common feature of accretion flows onto black holes that produce powerful jets.

Tazaki, Fumie; Ueda, Yoshihiro; Ishino, Yukiko; Eguchi, Satoshi; Isobe, Naoki [Department of Astronomy, Kyoto University, Kyoto 606-8502 (Japan); Terashima, Yuichi [Department of Physics, Ehime University, Matsuyama 790-8577 (Japan); Mushotzky, Richard F. [Department of Astronomy, University of Maryland, College Park, MD (United States)

2010-10-01

141

Suzaku Observation of the Brightest Broad-line Radio Galaxy 4C 50.55 (IGR J21247+5058)  

NASA Astrophysics Data System (ADS)

We report the results from a deep Suzaku observation of 4C 50.55 (IGR J21247+5058), the brightest broad-line radio galaxy in the hard X-ray (>10 keV) sky. The simultaneous broadband spectra over 1-60 keV can be represented by a cutoff power law with two layers of absorption and a significant reflection component from cold matter with a solid angle of ?/2? ? 0.2. A rapid flux rise by ~20% over 2 × 104 s is detected in the 2-10 keV band. The spectral energy distribution suggests that there is little contribution to the total X-ray emission from jets. Applying a thermal Comptonization model, we find that corona is optically thick (?e ? 3) and has a relatively low temperature (kT e ? 30 keV). The narrow iron-K emission line is consistent with a picture where the standard disk is truncated and/or its inner part is covered by optically thick Comptonizing corona smearing out relativistic broad-line features. The inferred disk structure may be a common feature of accretion flows onto black holes that produce powerful jets.

Tazaki, Fumie; Ueda, Yoshihiro; Ishino, Yukiko; Eguchi, Satoshi; Isobe, Naoki; Terashima, Yuichi; Mushotzky, Richard F.

2010-10-01

142

Hyperluminous reddened broad-line quasars at z ˜ 2 from the VISTA Hemisphere Survey and WISE all-sky survey  

NASA Astrophysics Data System (ADS)

We present the first sample of spectroscopically confirmed heavily reddened broad-line quasars selected using the new near-infrared VISTA Hemisphere Survey and Wide-field Infrared Survey Explorer (WISE) all-sky survey. Observations of four candidates with (J - K) > 2.5 and K ? 16.5 over ˜180 deg2 lead to confirmation that two are highly dust-reddened broad-line Type 1 quasars at z ˜ 2. The typical dust extinctions are AV ˜ 2-2.5 mag. We measure black hole masses of ˜109 M? and extinction-corrected bolometric luminosities of ˜1047 erg s-1, making them some of the brightest Type 1 quasars currently known. Despite this, these quasars lie well below the detection limits of wide-field optical surveys like the Sloan Digital Sky Survey (SDSS) with iAB > 22. We also present WISE photometry at 3-22 ?m, for our full sample of spectroscopically confirmed reddened quasars including those selected from the UKIDSS Large Area Survey. We demonstrate that the rest-frame infrared spectral energy distributions of these reddened quasars are similar to ultraviolet-luminous Type 1 quasars with significant hot dust emission and starburst quasar hosts like Mrk 231. The average 12-?m flux density of our reddened quasars is similar to that of the recently discovered hyperluminous infrared galaxy (HyLIRG) WISE 1814+3412 (z = 2.452) at similar redshifts, with two of our reddened quasars also having comparable 22-?m flux densities to this extreme HyLIRG. These optically faint, heavily reddened broad-line quasars are therefore among the most mid-infrared-luminous galaxies at z ˜ 2, now being discovered using WISE.

Banerji, Manda; McMahon, Richard G.; Hewett, Paul C.; Gonzalez-Solares, Eduardo; Koposov, Sergey E.

2013-02-01

143

An XMM-Newton survey of broad iron lines in Seyfert galaxies  

Microsoft Academic Search

We present an analysis of the X-ray spectra of a sample of 37 observations of 26 Seyfert galaxies observed by XMM-Newton in order to characterize their iron Kalpha emission. All objects show evidence for iron line emission in the 6-7 keV band. A narrow `core' at 6.4 keV is seen almost universally in the spectra, and we model this using

K. Nandra; P. M. O'Neill; I. M. George; J. N. Reeves

2007-01-01

144

Energy dependence of polarization across broad deexcitation gamma-ray line profiles  

NASA Astrophysics Data System (ADS)

The energy profiles of deexcitation gamma-ray lines from recoiling inelastically scattered nuclei exhibit detailed structure. MeV-wide gamma-ray lines from the direction of the Orion nebula have been detected (H. Bloemen, et al., Astr. and Astrophys. L5, 281 (1994).) by COMPTEL whose source is postulated to be cosmic ray carbon and oxygen nuclei shock accelerated near supernova remnants colliding with ambient hydrogen and helium. Even when the heavy ion velocity distributions are isotropic, structure characteristic of the multipolarity of the gamma transition remains (A. M. Bykov et al, Astr. and Astrophys. 607, L37 (1996); B. Kozlovsky et al, Astrophys. J. 484, (1997).). In experiments in which the energy dependent structure of the deexcitation gamma-ray profiles is not resolved, the gammas display a high degree of linear polarization that rapidly changes with gamma-beam angle. We calculate the polarization, both linear and circular, as a function of gamma-ray energy across the laboratory line profiles of C12*(4.44) and O16*(6.13) inelastically excited by protons and alphas. We then investigate the polarization in the surviving structures for isotropic energetic ions colliding with ^1H and ^4He.

Werntz, Carl; Lang, F. L.

1998-04-01

145

On reverberation and cross-correlation estimates of the size of the broad-line region in active galactic nuclei  

NASA Astrophysics Data System (ADS)

It is known that the dependence of the emission-line luminosity of a typical cloud in the active galactic nuclei (AGN) broad-line regions (BLRs) upon the incident flux of ionizing continuum can be non-linear. We study how this non-linearity can be taken into account in estimating the size of the BLR by means of the `reverberation' methods. We show that the BLR size estimates obtained by cross-correlation of emission-line and continuum light curves can be much (up to an order of magnitude) less than the values obtained by reverberation modelling. This is demonstrated by means of numerical cross-correlation and reverberation experiments with model continuum flares and emission-line transfer functions and by means of practical reverberation modelling of the observed optical spectral variability of NGC4151. The time behaviour of NGC4151 in the H? and H? lines is modelled on the basis of the observational data by Kaspi et al. and the theoretical BLR model by Shevchenko. The values of the BLR parameters are estimated that allow to judge on the size and physical characteristics of the BLR. The small size of the BLR, as determined by the cross-correlation method from the data of Kaspi et al., is shown to be an artefact of this method. So, the hypothesis that the BLR size varies in time is not necessitated by the observational data.

Melnikov, A. V.; Shevchenko, I. I.

2008-09-01

146

An XMM-Newton survey of broad iron lines in Seyfert galaxies  

Microsoft Academic Search

We present an analysis of the X-ray spectra of a sample of 37 observations of\\u000a26 Seyfert galaxies observed by XMM-Newton in order to characterize their iron\\u000aK emission. All objects show evidence for iron line emission in the 6-7 keV\\u000aband. A narrow core at 6.4 keV is seen almost universally in the spectra, and\\u000awe model this using

K. Nandra; P. M. O'Neill; I. M. George; J. N. Reeves

2007-01-01

147

Final Report: A Broad Research Project on the Sciences of Complexity, September 15, 1994 - November 15, 1999  

SciTech Connect

DOE support for a broad research program in the sciences of complexity permitted the Santa Fe Institute to initiate new collaborative research within its integrative core activities as well as to host visitors to participate in research on specific topics that serve as motivation and testing ground for the study of the general principles of complex systems. Results are presented on computational biology, biodiversity and ecosystem research, and advanced computing and simulation.

None

2000-02-01

148

A test of the failed disc wind scenario for the origin of the broad-line region in active galactic nuclei  

NASA Astrophysics Data System (ADS)

It has been recently proposed that the broad-line region in active galactic nuclei originates from dusty clouds driven from the accretion disc by radiation pressure, at a distance from the black hole where the disc is cooler than the dust sublimation temperature. We test this scenario by checking the consistency of independent broad-line region and accretion disc reverberation measurements, for a sample of 11 well-studied active galactic nuclei. We show that independent disc and broad-line region reverberation mapping measurements are compatible with a universal disc temperature at the H? radius of T(RH?) ? 1670 ± 231 K which is close to typical dust sublimation temperatures.

Galianni, Pasquale; Horne, Keith

2013-11-01

149

A test of the failed disc wind scenario for the origin of the broad-line region in active galactic nuclei  

NASA Astrophysics Data System (ADS)

It has been recently proposed that the broad-line region in active galactic nuclei originates from dusty clouds driven from the accretion disc by radiation pressure, at a distance from the black hole where the disc is cooler than the dust sublimation temperature. We test this scenario by checking the consistency of independent broad-line region and accretion disc reverberation measurements, for a sample of 11 well-studied active galactic nuclei. We show that independent disc and broad-line region reverberation mapping measurements are compatible with a universal disc temperature at the H? radius of T(RH?) ? 1670 ± 231 K which is close to typical dust sublimation temperatures.

Galianni, Pasquale; Horne, Keith

2013-09-01

150

CHANDRA DETECTION OF A PARSEC SCALE WIND IN THE BROAD-LINE RADIO GALAXY 3C 382  

SciTech Connect

We present unambiguous evidence for a parsec scale wind in the broad-line radio galaxy 3C 382, the first radio-loud active galactic nucleus, with R{sub L} = log{sub 10}(f{sub 5GHz}/f{sub 4400})>1, whereby an outflow has been measured with X-ray grating spectroscopy. A 118 ks Chandra grating (HETG) observation of 3C 382 has revealed the presence of several high ionization absorption lines in the soft X-ray band, from Fe, Ne, Mg, and Si. The absorption lines are blueshifted with respect to the systemic velocity of 3C 382 by -840 {+-} 60 km s{sup -1} and are resolved by Chandra with a velocity width of {sigma} = 340 {+-} 70 km s{sup -1}. The outflow appears to originate from a single zone of gas of column density N{sub H} = 1.3 x 10{sup 21} cm{sup -2} and ionization parameter log({xi}/erg cm s{sup -1}) = 2.45. From the above measurements we calculate that the outflow is observed on parsec scales, within the likely range from 10to1000 pc, i.e., consistent with an origin in the narrow-line region.

Reeves, J. N. [Astrophysics Group, School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire ST5 5BG (United Kingdom); Sambruna, R. M. [NASA/GSFC, Code 662, Greenbelt, MD 20771 (United States); Braito, V. [University of Leicester, Department of Physics and Astronomy, University Road, Leicester LE1 7RH (United Kingdom); Eracleous, Michael [Department of Astronomy and Astrophysics and Center for Gravitational Wave Physics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)], E-mail: jnr@astro.keele.ac.uk

2009-09-10

151

Chandra Detection of a Parsec Scale Wind in the Broad-Line Radio Galaxy 3C 382  

NASA Astrophysics Data System (ADS)

We present unambiguous evidence for a parsec scale wind in the broad-line radio galaxy 3C 382, the first radio-loud active galactic nucleus, with R L = log10(f 5 GHz/f 4400)>1, whereby an outflow has been measured with X-ray grating spectroscopy. A 118 ks Chandra grating (HETG) observation of 3C 382 has revealed the presence of several high ionization absorption lines in the soft X-ray band, from Fe, Ne, Mg, and Si. The absorption lines are blueshifted with respect to the systemic velocity of 3C 382 by -840 ± 60 km s-1 and are resolved by Chandra with a velocity width of ? = 340 ± 70 km s-1. The outflow appears to originate from a single zone of gas of column density N H = 1.3 × 1021 cm-2 and ionization parameter log(?/erg cm s-1) = 2.45. From the above measurements we calculate that the outflow is observed on parsec scales, within the likely range from 10to1000 pc, i.e., consistent with an origin in the narrow-line region.

Reeves, J. N.; Sambruna, R. M.; Braito, V.; Eracleous, Michael

2009-09-01

152

Observations of Broad Emission Lines in Wolf-Rayet Winds with Long-Baseline Interferometry  

NASA Astrophysics Data System (ADS)

We present results of milli-arcsecond (mas) observations of six Wolf-Rayet stars taken in 2003 with the Palomar Testbed Interferometer (PTI) and the Keck Interferometer (KI) in the K band (2.0-2.4 microns). PTI has a nominal fringe spacing of 4 mas in the K band, whereas KI has a fringe spacing of 5.2 mas. The purpose of these observations was to exploit this high resolution to help determine binarity, which is unknown for many Wolf-Rayet in systems. In addition, we have resolved He emission lines in narrowband ( 0.1 micron channel) measurements taken with both interferometers. Reduction of the observations yield visibilities and derived angular sizes in 4 or 5 spectral channels across the K band, revealing stratification of the stellar atmospheres. We have also recorded evolution in some resolved spectral features, indicating structure in the winds; however, follow-up interferometric observations are needed to better quantify this phenomena. We present the observations, some of the narrow-band data and initial conclusions based on our findings. We acknowledge support from the Donald Menzel Memorial Fund and the Rocky Mountain NASA Spacegrant Consortium at the University of Denver.

Hart, Alexa H.; Jurgenson, C. A.; Creech-Eakman, M. J.; Thompson, R. R.; Stencel, R. E.

2007-12-01

153

Are we Seeing the Earliest Stage of Galaxy Evolution in Low-Ionization Broad Absorption Line Quasars?  

NASA Astrophysics Data System (ADS)

Common evolutionary models have the merger of two gas-rich spiral galaxies result in the birth of a quasar. About 10-20% of quasars show Broad Absorption Lines (BALs), interpreted as gaseous outflows with speeds up to 30,000 km/s. Though most of the BAL quasars show only high ionization outflows (such as C IV), about 10% show low-ionization lines ("LoBALs"), like Mg II. BAL quasars are dusty, and the LoBALs are dustier still. How does the dust fit in? Studies suggest that BAL quasars could either be explained by a unified model or by an evolutionary model. In the unified models, the outflows originate as an accretion disk wind, with normal and BAL quasars differing only in viewing angle. In evolutionary models, dusty BAL quasars are a stage between the merger of the progenitor galaxies and before the emergence of a normal quasar, and the even dustier LoBALs would be the very first part of this stage. In this case, we would expect their host galaxies to be more distorted than normal quasars. In this study, we analyze LoBALs at redshifts of 0.4 < z < 0.7, identified from broad-absorption Mg II lines in Sloan spectra. Using the Hubble's WFC3 IR imagery, we first perform careful PSF fitting and removal to reveal the host galaxies. We then compare the distortion of their hosts to a control sample, using the non-parametric techniques of the Gini coefficient and concentration index.

Hamilton, Timothy S.; Turnshek, D. A.

2013-01-01

154

Diagnostics of Quasar Broad Absorption Line Geometry: X-Ray Observations and Two-dimensional Optical Spectroscopy  

NASA Astrophysics Data System (ADS)

A new generation of sensitive X-ray measurements are indicating that the existence of X-ray attenuation column densities, NH>1024 cm-2, is quite common among broad absorption line quasars (BALQSOs). This is significant to the geometry of the broad absorption line (BAL) outflow. In particular, such an X-ray shield also shields equatorial accretion disk winds from the UV, thereby preventing high-velocity equatorial outflows from being launched. By contrast, bipolar winds initiated by continuum radiation pressure from the funnel of a slim accretion disk flare outward (like a trumpet) and offer vastly different absorbing columns to the X-ray and UV emission that are emitted from distinct regions of the disk, ~6M and ~10M-40M, respectively (where M is the radius of the black hole). Recent numerical work indicates that it is also possible to launch bipolar outflows from the inner regions of a thin disk. The recent discovery with VLBI that the Galactic analog of a BALQSO, the X-ray binary Circinus X-1 (with high-velocity P Cygni X-ray absorption lines), is viewed virtually along the radio jet axis (and therefore along the spin axis of the black hole and the normal to the accretion disk) has rekindled interest in the bipolar models of BALQSOs. We explore this possibility by studying the nearest BALQSO, Mrk 231. High-resolution two-dimensional optical spectroscopy and VLBI mappings of the radio jet axis indicate that the BAL outflow is parallel to the parsec-scale radio jet.

Punsly, Brian; Lipari, Sebastian

2005-04-01

155

The acidity of niobic acid studied by 1H broad-line NMR at 4 K and H MAS NMR at room temperature: comparison with other solid acids  

Microsoft Academic Search

The acidity of niobium pentoxide calcined at 573 K has been studied by interacting water molecules and the solid acid using 1H broad-line NMR at 4 K and MAS NMR at room temperature. 1H Broad-line NMR in ‘rigid lattice’ conditions allows the determination of the numbers of the oxygen-protonated species (H3O+ and H2O ··· HO species, unreacted OH groups or

Patrice Batamack; Robert Vincent; Jacques Fraissard

1996-01-01

156

Measured Metallicities at the Sites of Nearby Broad-Lined Type Ic Supernovae and Implications for the Supernovae Gamma-Ray Burst Connection  

Microsoft Academic Search

We compare the chemical abundances at the sites of 12 nearby (z < 0.14) Type Ic supernovae (SN Ic) that showed broad lines, but had no observed gamma-ray burst (GRB), with the chemical abundances in five nearby (z < 0.25) galaxies at the sites of GRBs where broad-lined SN Ic were seen after the fireball had faded. It has previously

M. Modjaz; L. Kewley; R. P. Kirshner; K. Z. Stanek; P. Challis; P. M. Garnavich; J. E. Greene; P. L. Kelly; J. L. Prieto

2008-01-01

157

Discovery of Ultra-fast Outflows in a Sample of Broad-line Radio Galaxies Observed with Suzaku  

NASA Astrophysics Data System (ADS)

We present the results of a uniform and systematic search for blueshifted Fe K absorption lines in the X-ray spectra of five bright broad-line radio galaxies observed with Suzaku. We detect, for the first time in radio-loud active galactic nuclei (AGNs) at X-rays, several absorption lines at energies greater than 7 keV in three out of five sources, namely, 3C 111, 3C 120, and 3C 390.3. The lines are detected with high significance according to both the F-test and extensive Monte Carlo simulations. Their likely interpretation as blueshifted Fe XXV and Fe XXVI K-shell resonance lines implies an origin from highly ionized gas outflowing with mildly relativistic velocities, in the range v ~= 0.04-0.15c. A fit with specific photoionization models gives ionization parameters in the range log ? ~= 4-5.6 erg s-1 cm and column densities of N H ~= 1022-1023 cm-2. These characteristics are very similar to those of the ultra-fast outflows (UFOs) previously observed in radio-quiet AGNs. Their estimated location within ~0.01-0.3 pc of the central super-massive black hole suggests a likely origin related with accretion disk winds/outflows. Depending on the absorber covering fraction, the mass outflow rate of these UFOs can be comparable to the accretion rate and their kinetic power can correspond to a significant fraction of the bolometric luminosity and is comparable to their typical jet power. Therefore, these UFOs can play a significant role in the expected feedback from the AGN to the surrounding environment and can give us further clues on the relation between the accretion disk and the formation of winds/jets in both radio-quiet and radio-loud AGNs.

Tombesi, F.; Sambruna, R. M.; Reeves, J. N.; Braito, V.; Ballo, L.; Gofford, J.; Cappi, M.; Mushotzky, R. F.

2010-08-01

158

DISCOVERY OF ULTRA-FAST OUTFLOWS IN A SAMPLE OF BROAD-LINE RADIO GALAXIES OBSERVED WITH SUZAKU  

SciTech Connect

We present the results of a uniform and systematic search for blueshifted Fe K absorption lines in the X-ray spectra of five bright broad-line radio galaxies observed with Suzaku. We detect, for the first time in radio-loud active galactic nuclei (AGNs) at X-rays, several absorption lines at energies greater than 7 keV in three out of five sources, namely, 3C 111, 3C 120, and 3C 390.3. The lines are detected with high significance according to both the F-test and extensive Monte Carlo simulations. Their likely interpretation as blueshifted Fe XXV and Fe XXVI K-shell resonance lines implies an origin from highly ionized gas outflowing with mildly relativistic velocities, in the range v {approx_equal} 0.04-0.15c. A fit with specific photoionization models gives ionization parameters in the range log {xi} {approx_equal} 4-5.6 erg s{sup -1} cm and column densities of N {sub H} {approx_equal} 10{sup 22}-10{sup 23} cm{sup -2}. These characteristics are very similar to those of the ultra-fast outflows (UFOs) previously observed in radio-quiet AGNs. Their estimated location within {approx}0.01-0.3 pc of the central super-massive black hole suggests a likely origin related with accretion disk winds/outflows. Depending on the absorber covering fraction, the mass outflow rate of these UFOs can be comparable to the accretion rate and their kinetic power can correspond to a significant fraction of the bolometric luminosity and is comparable to their typical jet power. Therefore, these UFOs can play a significant role in the expected feedback from the AGN to the surrounding environment and can give us further clues on the relation between the accretion disk and the formation of winds/jets in both radio-quiet and radio-loud AGNs.

Tombesi, F. [Dipartimento di Astronomia, Universita di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Sambruna, R. M.; Mushotzky, R. F. [Laboratory for High Energy Astrophysics, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Reeves, J. N.; Gofford, J. [Astrophysics Group, School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire ST5 5BG (United Kingdom); Braito, V. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Ballo, L. [Istituto de Fisica de Cantabria (CSIC-UC), 39005 Santander (Spain); Cappi, M., E-mail: tombesi@iasfbo.inaf.i [INAF-IASF Bologna, Via Gobetti 101, I-40129 Bologna (Italy)

2010-08-10

159

Discovery of the Broad-lined Type Ic SN 2013cq Associated with the Very Energetic GRB 130427A  

NASA Astrophysics Data System (ADS)

Long-duration gamma-ray bursts (GRBs) at z < 1 are found in most cases to be accompanied by bright, broad-lined Type Ic supernovae (SNe Ic-BL). The highest-energy GRBs are mostly located at higher redshifts, where the associated SNe are hard to detect observationally. Here, we present early and late observations of the optical counterpart of the very energetic GRB 130427A. Despite its moderate redshift, z = 0.3399 ± 0.0002, GRB 130427A is at the high end of the GRB energy distribution, with an isotropic-equivalent energy release of E iso ~ 9.6 × 1053 erg, more than an order of magnitude more energetic than other GRBs with spectroscopically confirmed SNe. In our dense photometric monitoring, we detect excess flux in the host-subtracted r-band light curve, consistent with that expected from an emerging SN, ~0.2 mag fainter than the prototypical SN 1998bw. A spectrum obtained around the time of the SN peak (16.7 days after the GRB) reveals broad undulations typical of SNe Ic-BL, confirming the presence of an SN, designated SN 2013cq. The spectral shape and early peak time are similar to those of the high expansion velocity SN 2010bh associated with GRB 100316D. Our findings demonstrate that high-energy, long-duration GRBs, commonly detected at high redshift, can also be associated with SNe Ic-BL, pointing to a common progenitor mechanism.

Xu, D.; de Ugarte Postigo, A.; Leloudas, G.; Krühler, T.; Cano, Z.; Hjorth, J.; Malesani, D.; Fynbo, J. P. U.; Thöne, C. C.; Sánchez-Ramírez, R.; Schulze, S.; Jakobsson, P.; Kaper, L.; Sollerman, J.; Watson, D. J.; Cabrera-Lavers, A.; Cao, C.; Covino, S.; Flores, H.; Geier, S.; Gorosabel, J.; Hu, S. M.; Milvang-Jensen, B.; Sparre, M.; Xin, L. P.; Zhang, T. M.; Zheng, W. K.; Zou, Y. C.

2013-10-01

160

BEPPOSAX observations of the massive X-ray pulsar Cen X-3: Broad-band spectra and iron line diagnostic.  

NASA Astrophysics Data System (ADS)

The BeppoSAX satellite pointed to the massive X-ray pulsar Cen X-3 for the first time during the Science Verification Phase (SVP). The source was found in a low luminosity state (L ? 3.8 × 1036 ergs/s). Cen X-3 was observed again in the Guest Observer Program (GOP) and was found in a much higher luminosity state (L ? 4.3 × 1037 ergs/s ). This second observation includes also the source eclipse and the eclipse egress. We present the pulse profiles and the average broad-band spectra (0.5 - 80 keV) of the two observations and discuss different overall continuum models to fit these spectra. In particular, we report results on the variation of the iron K-line parameters as a function of the different source states: eclipse, low luminosity state and high luminosity state

del Sordo, S.; dal Fiume, D.; Oriandini, M.; Piraino, S.; Santangelo, A.; Segreto, A.

161

PTF 10bzf (SN 2010ah): A Broad-line Ic Supernova Discovered by the Palomar Transient Factory  

NASA Astrophysics Data System (ADS)

We present the discovery and follow-up observations of a broad-line Type Ic supernova (SN), PTF 10bzf (SN 2010ah), detected by the Palomar Transient Factory (PTF) on 2010 February 23. The SN distance is cong218 Mpc, greater than GRB 980425/SN 1998bw and GRB 060218/SN 2006aj, but smaller than the other SNe firmly associated with gamma-ray bursts (GRBs). We conducted a multi-wavelength follow-up campaign with Palomar 48 inch, Palomar 60 inch, Gemini-N, Keck, Wise, Swift, the Allen Telescope Array, Combined Array for Research in Millimeter-wave Astronomy, Westerbork Synthesis Radio Telescope, and Expanded Very Large Array. Here we compare the properties of PTF 10bzf with those of SN 1998bw and other broad-line SNe. The optical luminosity and spectral properties of PTF 10bzf suggest that this SN is intermediate, in kinetic energy and amount of 56Ni, between non-GRB-associated SNe like 2002ap or 1997ef, and GRB-associated SNe like 1998bw. No X-ray or radio counterpart to PTF 10bzf was detected. X-ray upper limits allow us to exclude the presence of an underlying X-ray afterglow as luminous as that of other SN-associated GRBs such as GRB 030329 or GRB 031203. Early-time radio upper limits do not show evidence for mildly relativistic ejecta. Late-time radio upper limits rule out the presence of an underlying off-axis GRB, with energy and wind density similar to the SN-associated GRB 030329 and GRB 031203. Finally, by performing a search for a GRB in the time window and at the position of PTF 10bzf, we find that no GRB in the interplanetary network catalog could be associated with this SN.

Corsi, A.; Ofek, E. O.; Frail, D. A.; Poznanski, D.; Arcavi, I.; Gal-Yam, A.; Kulkarni, S. R.; Hurley, K.; Mazzali, P. A.; Howell, D. A.; Kasliwal, M. M.; Green, Y.; Murray, D.; Sullivan, M.; Xu, D.; Ben-ami, S.; Bloom, J. S.; Cenko, S. B.; Law, N. M.; Nugent, P.; Quimby, R. M.; Pal'shin, V.; Cummings, J.; Connaughton, V.; Yamaoka, K.; Rau, A.; Boynton, W.; Mitrofanov, I.; Goldsten, J.

2011-11-01

162

The central structure of Broad Absorption Line QSOs: observational characteristics in the cm-mm wavelength domain  

NASA Astrophysics Data System (ADS)

Accounting for ~20% of the total QSO population, Broad Absorption Line QSOs are still an unsolved problem in the AGN context. They present wide troughs in the UV spectrum, due to material with velocities up to 0.2 c toward the observer. The two models proposed in literature try to explain them as a particular phase of the evolution of QSOs or as normal QSOs, but seen from a particular line of sight. We built a statistically complete sample of Radio-Loud BAL QSOs, and carried out an observing campaign to piece together the whole spectrum in the cm wavelength domain, and highlight all the possible differences with respect to a comparison sample of Radio-Loud non-BAL QSOs. VLBI observations at high angular resolution have been performed, to study the pc-scale morphology of these objects. Finally, we tried to detect a possible dust component with observations at mm-wavelengths. Results do not seem to indicate a young age for all BAL QSOs. Instead a variety of orientations and morphologies have been found, constraining the outflows foreseen by the orientation model to have different possible angles with respect to the jet axis.

Bruni, G.; Mack, K.-H.; Dallacasa, D.; Montenegro-Montes, F. M.; Benn, C. R.; Carballo, R.; González-Serrano, J. I.; Holt, J.; Jiménez-Luján, F.

2012-07-01

163

Comparing Broad-line Region Gas Metallicity with Black Hole Mass and Eddington Ratio Using Low-z QSOs  

NASA Astrophysics Data System (ADS)

We investigate the broad-line region (BLR) gas metallicity of a sample of 70 Palomar-Green QSOs at z < 0.5 using archival UV spectra obtained with the HST and IUE. By utilizing the flux ratio of UV emission lines (i.e., NV/CIV,(SiIV+OIV)/CIV, NV/HeII, and AlIII/CIV) as metallicity indicators, we compare BLR gas metallicity with AGN properties, i.e., black hole mass, luminosity, and Eddinton ratio. We find that BLR metallicity correlates with Eddington ratio while the dependency on black hole mass is much weaker. Although these trends of low-z AGNs appear to be different from those of high-z QSOs, the difference is partly caused by the limited dynamical range of the samples. We conclude that metal enrichment at the center of galaxies is closely connected to the accretion activity of black holes as manifested by the metallicity - Eddington ratio correlation and that the scatter of the metallicity - black hole mass correlation increases over cosmic time due to various nuclear star formation mechanism.

Woo, Jong-Hak; Shin, J.; Nagao, T.

2013-01-01

164

1992 annual report on scientific programs: A broad research program on the sciences of complexity  

SciTech Connect

In 1992 the Santa Fe Institute hosted more than 100 short- and long-term research visitors who conducted a total of 212 person-months of residential research in complex systems. To date this 1992 work has resulted in more than 50 SFI Working Papers and nearly 150 publications in the scientific literature. The Institute`s book series in the sciences of complexity continues to grow, now numbering more than 20 volumes. The fifth annual complex systems summer school brought nearly 60 graduate students and postdoctoral fellows to Santa Fe for an intensive introduction to the field. Research on complex systems-the focus of work at SFI-involves an extraordinary range of topics normally studied in seemingly disparate fields. Natural systems displaying complex adaptive behavior range upwards from DNA through cells and evolutionary systems to human societies. Research models exhibiting complex behavior include spin glasses, cellular automata, and genetic algorithms. Some of the major questions facing complex systems researchers are: (1) explaining how complexity arises from the nonlinear interaction of simple components; (2) describing the mechanisms underlying high-level aggregate behavior of complex systems (such as the overt behavior of an organism, the flow of energy in an ecology, the GNP of an economy); and (3) creating a theoretical framework to enable predictions about the likely behavior of such systems in various conditions.

Not Available

1992-12-31

165

Broad Line Radio Galaxies Observed with Fermi-LAT: The Origin of the GeV Gamma-Ray Emission  

SciTech Connect

We report on a detailed investigation of the {gamma}-ray emission from 18 broad line radio galaxies (BLRGs) based on two years of Fermi Large Area Telescope (LAT) data. We confirm the previously reported detections of 3C 120 and 3C 111 in the GeV photon energy range; a detailed look at the temporal characteristics of the observed {gamma}-ray emission reveals in addition possible flux variability in both sources. No statistically significant {gamma}-ray detection of the other BLRGs was however found in the considered dataset. Though the sample size studied is small, what appears to differentiate 3C 111 and 3C 120 from the BLRGs not yet detected in {gamma}-rays is the particularly strong nuclear radio flux. This finding, together with the indications of the {gamma}-ray flux variability and a number of other arguments presented, indicate that the GeV emission of BLRGs is most likely dominated by the beamed radiation of relativistic jets observed at intermediate viewing angles. In this paper we also analyzed a comparison sample of high accretion-rate Seyfert 1 galaxies, which can be considered radio-quiet counterparts of BLRGs, and found none were detected in {gamma}-rays. A simple phenomenological hybrid model applied for the broad-band emission of the discussed radio-loud and radio-quiet type 1 active galaxies suggests that the relative contribution of the nuclear jets to the accreting matter is {ge} 1% on average for BLRGs, while {le} 0.1% for Seyfert 1 galaxies.

Kataoka, J.; /Waseda U., RISE; Stawarz, L.; /JAXA, Sagamihara /Jagiellonian U., Astron. Observ.; Takahashi, Y.; /Waseda U., RISE; Cheung, C.C.; /Natl. Acad. Sci. /Naval Research Lab, Wash., D.C.; Hayashida, M.; /SLAC /Stanford U., HEPL /KIPAC, Menlo Park; Grandi, P.; /Bologna Observ.; Burnett, T.H.; /Washington U., Seattle; Celotti, A.; /SISSA, Trieste; Fegan, S.J.; Fortin, P.; /Ecole Polytechnique; Maeda, K.; Nakamori, T.; /Waseda U., RISE; Taylor, G.B.; /New Mexico U.; Tosti, G.; /INFN, Perugia /Perugia U.; Digel, S.W.; /SLAC /Stanford U., HEPL /KIPAC, Menlo Park; McConville, W.; /NASA, Goddard /Maryland U.; Finke, J.; /Naval Research Lab, Wash., D.C.; D'Ammando, F.; /IASF, Palermo /INAF, Rome

2012-06-07

166

SN 2010ay IS A LUMINOUS AND BROAD-LINED TYPE Ic SUPERNOVA WITHIN A LOW-METALLICITY HOST GALAXY  

SciTech Connect

We report on our serendipitous pre-discovery detection and follow-up observations of the broad-lined Type Ic supernova (SN Ic) 2010ay at z = 0.067 imaged by the Pan-STARRS1 3{pi} survey just {approx}4 days after explosion. The supernova (SN) had a peak luminosity, M{sub R} Almost-Equal-To -20.2 mag, significantly more luminous than known GRB-SNe and one of the most luminous SNe Ib/c ever discovered. The absorption velocity of SN 2010ay is v{sub Si} Almost-Equal-To 19 Multiplication-Sign 10{sup 3} km s{sup -1} at {approx}40 days after explosion, 2-5 times higher than other broad-lined SNe and similar to the GRB-SN 2010bh at comparable epochs. Moreover, the velocity declines {approx}2 times slower than other SNe Ic-BL and GRB-SNe. Assuming that the optical emission is powered by radioactive decay, the peak magnitude implies the synthesis of an unusually large mass of {sup 56}Ni, M{sub Ni} = 0.9 M{sub Sun }. Applying scaling relations to the light curve, we estimate a total ejecta mass, M{sub ej} Almost-Equal-To 4.7 M{sub Sun }, and total kinetic energy, E{sub K} Almost-Equal-To 11 Multiplication-Sign 10{sup 51} erg. The ratio of M{sub Ni} to M{sub ej} is {approx}2 times as large for SN 2010ay as typical GRB-SNe and may suggest an additional energy reservoir. The metallicity (log (O/H){sub PP04} + 12 = 8.19) of the explosion site within the host galaxy places SN 2010ay in the low-metallicity regime populated by GRB-SNe, and {approx}0.5(0.2) dex lower than that typically measured for the host environments of normal (broad-lined) SNe Ic. We constrain any gamma-ray emission with E{sub {gamma}} {approx}< 6 Multiplication-Sign 10{sup 48} erg (25-150 keV), and our deep radio follow-up observations with the Expanded Very Large Array rule out relativistic ejecta with energy E {approx}> 10{sup 48} erg. We therefore rule out the association of a relativistic outflow like those that accompanied SN 1998bw and traditional long-duration gamma-ray bursts (GRBs), but we place less-stringent constraints on a weak afterglow like that seen from XRF 060218. If this SN did not harbor a GRB, these observations challenge the importance of progenitor metallicity for the production of relativistic ejecta and suggest that other parameters also play a key role.

Sanders, N. E.; Soderberg, A. M.; Foley, R. J.; Chornock, R.; Chomiuk, L.; Berger, E. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Valenti, S.; Smartt, S.; Botticella, M. T. [Astrophysics Research Centre, School of Maths and Physics, Queen's University, Belfast BT7 1NN (United Kingdom); Hurley, K. [Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Barthelmy, S. D.; Gehrels, N.; Cline, T. [NASA Goddard Space Flight Center, Code 661, Greenbelt, MD 20771 (United States); Levesque, E. M. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Narayan, G. [Department of Physics, Harvard University, Cambridge, MA 02138 (United States); Briggs, M. S.; Connaughton, V. [CSPAR, University of Alabama in Huntsville, Huntsville, AL (United States); Terada, Y. [Department of Physics, Saitama University, Shimo-Okubo, Sakura-ku, Saitama-shi, Saitama 338-8570 (Japan); Golenetskii, S.; Mazets, E., E-mail: nsanders@cfa.harvard.edu [Ioffe Physico-Technical Institute, Laboratory for Experimental Astrophysics, 26 Polytekhnicheskaya, St. Petersburg 194021 (Russian Federation); and others

2012-09-10

167

The Black Hole-Bulge Relationship in Luminous Broad-Line Active Galactic Nuclei and Host Galaxies  

NASA Astrophysics Data System (ADS)

We have measured the stellar velocity dispersions (?*) and estimated the central black hole (BH) masses for over 900 broad-line active galactic nuclei (AGNs) observed with the Sloan Digital Sky Survey. The sample includes objects which have redshifts up to z = 0.452, high-quality spectra, and host galaxy spectra dominated by an early-type (bulge) component. The AGN and host galaxy spectral components were decomposed using an eigenspectrum technique. The BH masses (M BH) were estimated from the AGN broad-line widths, and the velocity dispersions were measured from the stellar absorption spectra of the host galaxies. The range of black hole masses covered by the sample is approximately 106 < M BH < 109 M sun. The host galaxy luminosity-velocity dispersion relationship follows the well-known Faber-Jackson relation for early-type galaxies, with a power-law slope 4.33 ± 0.21. The estimated BH masses are correlated with both the host luminosities (LH ) and the stellar velocity dispersions (?*), similar to the relationships found for low-redshift, bulge-dominated galaxies. The intrinsic scatters in the correlations are large (~0.4 dex), but the very large sample size allows tight constraints to be placed on the mean relationships: M BH vprop L 0.73±0.05 H and M BH vprop ?3.34±0.24 *. The amplitude of the M BH-?* relation depends on the estimated Eddington ratio, such that objects with larger Eddington ratios have smaller black hole masses than expected at a given velocity dispersion. While this dependence is probably caused at least in part by sample selection effects, it can account for the intrinsic scatter in the M BH-?* relation, and may tie together the accretion rate with physical properties of the host bulge component. We find no significant evolution in the M BH-?* relation with redshift, up to z ? 0.4, after controlling for possible dependences on other variables. Interested readers can contact the authors to obtain the eigenspectrum decomposition coefficients of our objects.

Shen, Jiajian; Vanden Berk, Daniel E.; Schneider, Donald P.; Hall, Patrick B.

2008-03-01

168

A broad research program on the sciences of complexity: Annual report  

SciTech Connect

1988 was the first full year of operation on the Santa Fe Institute, under multiyear grants from the Department of Energy and the National Science Foundation, with additional major grants from Citicorp, Russell Sage Foundation, and MacArthur Foundation. The research, educational, and publishing program of the Institute developed rapidly, especially in the last half of 1988. All of the seemingly disparate subjects in the program represent examples of complex systems with certain common properties that help define the content of an emerging general science of complexity. Major elements of progress in the SFI program were as follows: Economy; Theoretical Immunology; Global Security; Other Research; Summer School; Publishing Program; and Computer Support. This report describes proposed extensions of the 1988 programs into 1989 as well as proposed new workshops and research programs on complex adaptive systems; complexity, entropy, and the physics of information; 1989 complex systems summer school; evolution of human language; organization and evolution of prehistoric southwestern society; public policy studies; modeling human cognition and emotion; proteins, glasses, and spin glasses; theoretical ecology; and computational learning systems.

Not Available

1988-12-20

169

Star Formation in Self-gravitating Disks in Active Galactic Nuclei. II. Episodic Formation of Broad-line Regions  

NASA Astrophysics Data System (ADS)

This is the second in a series of papers discussing the process and effects of star formation in the self-gravitating disk around the supermassive black holes in active galactic nuclei (AGNs). We have previously suggested that warm skins are formed above the star-forming (SF) disk through the diffusion of warm gas driven by supernova explosions. Here we study the evolution of the warm skins when they are exposed to the powerful radiation from the inner part of the accretion disk. The skins initially are heated to the Compton temperature, forming a Compton atmosphere (CAS) whose subsequent evolution is divided into four phases. Phase I is the duration of pure accumulation supplied by the SF disk. During phase II clouds begin to form due to line cooling and sink to the SF disk. Phase III is a period of preventing clouds from sinking to the SF disk through dynamic interaction between clouds and the CAS because of the CAS overdensity driven by continuous injection of warm gas from the SF disk. Finally, phase IV is an inevitable collapse of the entire CAS through line cooling. This CAS evolution drives the episodic appearance of broad-line regions (BLRs). We follow the formation of cold clouds through the thermal instability of the CAS during phases II and III, using linear analysis. Since the clouds are produced inside the CAS, the initial spatial distribution of newly formed clouds and angular momentum naturally follow the CAS dynamics, producing a flattened disk of clouds. The number of clouds in phases II and III can be estimated, as well as the filling factor of clouds in the BLR. Since the cooling function depends on the metallicity, the metallicity gradients that originate in the SF disk give rise to different properties of clouds in different radial regions. We find from the instability analysis that clouds have column density N H <~ 1022 cm-2 in the metal-rich regions whereas they have N H >~ 1022 cm-2 in the metal-poor regions. The metal-rich clouds compose the high-ionization line regions whereas the metal-poor clouds are in low-ionization line (LIL) regions. Since metal-rich clouds are optically thin, they will be blown away by radiation pressure, forming the observed outflows. The outflowing clouds could set up a metallicity correlation between the BLRs and narrow-line regions. The LIL regions are episodic due to the mass cycle of clouds with the CAS in response to continuous injection by the SF disk, giving rise to different types of AGNs. Based on Sloan Digital Sky Survey quasar spectra, we identify a spectral sequence in light of emission-line equivalent width from phase I to IV. A key phase in the episodic appearance of the BLRs is bright type II AGNs with no or only weak BLRs, contrary to the popular picture in which the absence of a BLR is due to a low accretion rate. We discuss observational implications and tests of the theoretical predictions of this model.

Wang, Jian-Min; Du, Pu; Baldwin, Jack A.; Ge, Jun-Qiang; Hu, Chen; Ferland, Gary J.

2012-02-01

170

STAR FORMATION IN SELF-GRAVITATING DISKS IN ACTIVE GALACTIC NUCLEI. II. EPISODIC FORMATION OF BROAD-LINE REGIONS  

SciTech Connect

This is the second in a series of papers discussing the process and effects of star formation in the self-gravitating disk around the supermassive black holes in active galactic nuclei (AGNs). We have previously suggested that warm skins are formed above the star-forming (SF) disk through the diffusion of warm gas driven by supernova explosions. Here we study the evolution of the warm skins when they are exposed to the powerful radiation from the inner part of the accretion disk. The skins initially are heated to the Compton temperature, forming a Compton atmosphere (CAS) whose subsequent evolution is divided into four phases. Phase I is the duration of pure accumulation supplied by the SF disk. During phase II clouds begin to form due to line cooling and sink to the SF disk. Phase III is a period of preventing clouds from sinking to the SF disk through dynamic interaction between clouds and the CAS because of the CAS overdensity driven by continuous injection of warm gas from the SF disk. Finally, phase IV is an inevitable collapse of the entire CAS through line cooling. This CAS evolution drives the episodic appearance of broad-line regions (BLRs). We follow the formation of cold clouds through the thermal instability of the CAS during phases II and III, using linear analysis. Since the clouds are produced inside the CAS, the initial spatial distribution of newly formed clouds and angular momentum naturally follow the CAS dynamics, producing a flattened disk of clouds. The number of clouds in phases II and III can be estimated, as well as the filling factor of clouds in the BLR. Since the cooling function depends on the metallicity, the metallicity gradients that originate in the SF disk give rise to different properties of clouds in different radial regions. We find from the instability analysis that clouds have column density N{sub H} {approx}< 10{sup 22} cm{sup -2} in the metal-rich regions whereas they have N{sub H} {approx}> 10{sup 22} cm{sup -2} in the metal-poor regions. The metal-rich clouds compose the high-ionization line regions whereas the metal-poor clouds are in low-ionization line (LIL) regions. Since metal-rich clouds are optically thin, they will be blown away by radiation pressure, forming the observed outflows. The outflowing clouds could set up a metallicity correlation between the BLRs and narrow-line regions. The LIL regions are episodic due to the mass cycle of clouds with the CAS in response to continuous injection by the SF disk, giving rise to different types of AGNs. Based on Sloan Digital Sky Survey quasar spectra, we identify a spectral sequence in light of emission-line equivalent width from phase I to IV. A key phase in the episodic appearance of the BLRs is bright type II AGNs with no or only weak BLRs, contrary to the popular picture in which the absence of a BLR is due to a low accretion rate. We discuss observational implications and tests of the theoretical predictions of this model.

WangJianmin; Du Pu; Ge Junqiang; Hu Chen [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquan Road, Beijing 100049 (China); Baldwin, Jack A. [Physics and Astronomy Department, 3270 Biomedical Physical Sciences Building, Michigan State University, East Lansing, MI 48824 (United States); Ferland, Gary J., E-mail: wangjm@mail.ihep.ac.cn [Department of Physics and Astronomy, 177 Chemistry/Physics Building, University of Kentucky, Lexington, KY 40506 (United States)

2012-02-20

171

Radio spectra and polarisation properties of a bright sample of radio-loud broad absorption line quasars  

NASA Astrophysics Data System (ADS)

Context. The origin of broad-absorption-line quasi-stellar objects (BAL QSOs) remains unclear. Accounting for ~20% of the QSO population, these objects have broad absorption lines in their optical spectra generated from outflows with velocities of up to 0.2 c. In this work, we present the results of a multi-frequency study of a well-defined radio-loud BAL QSO sample, and a comparison sample of radio-loud non-BAL QSOs, both selected from the Sloan Digital Sky Survey (SDSS). Aims: We aim to test which of the currently popular models of the BAL phenomenon - "orientation" or "evolutionary" - best accounts for the radio properties of BAL quasars. We also consider a third model in which BALs are produced by polar jets driven by radiation pressure. Methods: Observations from 1.4 to 43 GHz have been obtained with the VLA and Effelsberg telescopes, and data from 74 to 408 MHz have been compiled from the literature. The spectral indices give clues about the orientation, while the determination of the peak frequency can constrain the age, and test the evolutionary scenario, in which BAL QSOs are young QSOs. The fractional polarisation and the rotation measure in part reflect the local magnetic field strength and particle density. Results: The fractions of resolved sources in the BAL and non-BAL QSO samples are similar (16% versus (vs.) 12%). The resolved sources in the two samples have similar linear sizes (20 to 400 kpc) and morphologies. There is weak evidence that the fraction of variable sources amongst BAL QSOs is smaller. The fractions of candidate GHz-peaked sources are similar in the two samples (36 ± 12% vs. 23 ± 8%), suggesting that BAL QSOs are not generally younger than non-BAL QSOs. Both BAL and non-BAL QSOs have a wide range of spectral indices, including flat-spectrum and steep-spectrum sources, consistent with a broad range of orientations. There is weak evidence (91% confidence) that the spectral indices of the BAL QSOs are steeper than those of non-BAL QSOs, mildly favouring edge-on orientations. At a higher level of significance (?97%), the spectra of BAL QSOs are no flatter than those of non-BAL QSOs, which suggests that a polar orientation is not preferred. The distributions of fractional polarisation in the two samples have similar median values (1-3%). The distributions of rotation measure are also similar, the only outlier being the BAL QSO 1624+37, which has an extreme rest-frame rotation measure (from the literature) of -18 350 ± 570 rad m-2. Figure 3 and Tables 5-7, 9 are available in electronic form at http://www.aanda.org

Bruni, G.; Mack, K.-H.; Salerno, E.; Montenegro-Montes, F. M.; Carballo, R.; Benn, C. R.; González-Serrano, J. I.; Holt, J.; Jiménez-Luján, F.

2012-06-01

172

Discovery of a variable broad absorption line in the BL Lac object PKS B0138-097  

NASA Astrophysics Data System (ADS)

We report the discovery of a broad absorption line (BAL) of ~ 104 km s-1 in width in the previously known BL Lac object PKS 0138-097, which we tentatively identified as an Mg II BAL. This is the first detection of a BAL, which is sometimes seen in powerful quasars with high accretion rates, in a BL Lac object. The BAL was clearly detected in its spectra spanning two epochs at a high luminosity state taken in the Sloan Digital Sky Survey (SDSS), while it disappeared in three SDSS spectra taken at a low luminosity state. The BAL and its variability pattern were also found in its historical multi-epoch spectra in the literature, but have been overlooked previously. In its high resolution radio maps, PKS 0138-097 shows a core plus a onesided parsec-scale jet. The BAL variability can be interpreted as follows: The optical emission is dominated by the core in a high state and by the jet in a low state and the BAL material is located between the core and jet so that the BAL appears only when the core is shining. Our discovery suggests that outflows may also be produced in active galactic nuclei at a low accreting state.

Zhang, Shao-Hua; Wang, Hui-Yuan; Zhou, Hong-Yan; Wang, Ting-Gui; Jiang, Peng

2011-10-01

173

Multifrequency VLBI Observations of the Broad Absorption Line Quasar J1020+4320: Recently Restarted Jet Activity?  

NASA Astrophysics Data System (ADS)

This paper reports on very-long-baseline interferometry observations of the radio-loud broad absorption line (BAL) quasar J1020+4320 at 1.7, 2.3, 6.7, and 8.4 GHz using the Japanese VLBI network (JVN) and European VLBI network (EVN). The radio morphology is compact with a size of ˜10 pc. The convex radio spectrum has been stable over the last decade; an observed peak frequency of 3.2 GHz is equivalent to 9.5 GHz in the rest frame, suggesting an age on the order of ˜100 years as a radio source, according to an observed correlation between the linear size and the peak frequency of compact steep spectrum (CSS) and giga-hertz peaked spectrum (GPS) radio sources. A low-frequency radio excess suggests a relic of past jet activity. J1020+4320 may be one of the quasars with recurrent and short-lived jet activity during a BAL-outflowing phase.

Doi, Akihiro; Murata, Yasuhiro; Mochizuki, Nanako; Takeuchi, Hiroshi; Asada, Keiichi; Hayashi, Takayuki J.; Nagai, Hiroshi; Shibata, Katsunori M.; Oyama, Tomoaki; Jike, Takaaki; Fujisawa, Kenta; Sugiyama, Koichiro; Ogawa, Hideo; Kimura, Kimihiro; Honma, Mareki; Kobayashi, Hideyuki; Koyama, Shoko

2013-06-01

174

1993 Annual report on scientific programs: A broad research program on the sciences of complexity  

SciTech Connect

This report provides a summary of many of the research projects completed by the Santa Fe Institute (SFI) during 1993. These research efforts continue to focus on two general areas: the study of, and search for, underlying scientific principles governing complex adaptive systems, and the exploration of new theories of computation that incorporate natural mechanisms of adaptation (mutation, genetics, evolution).

NONE

1993-12-31

175

Juvenile Hormone Prevents Ecdysteroid-Induced Expression of Broad Complex RNAs in the Epidermis of the Tobacco Hornworm, Manduca sexta  

Microsoft Academic Search

A cDNA homolog of theDrosophila melanogaster Broad Complex (BRC)gene was isolated from the tobacco hornworm,Manduca sexta,which shows a predicted 88% amino acid identity withDrosophilaBRC in the N-terminal BTB domain. Three zinc finger domains encoding homologs of theDrosophilaZ2, Z3, and Z4 domains (93, 100, and 85% identity, respectively) were obtained by RT–PCR. InManducadorsal abdominal epidermis, BRC RNAs were not observed during

Baohua Zhou; Kiyoshi Hiruma; Tetsuro Shinoda; Lynn M. Riddiford

1998-01-01

176

Elicitation of broadly reactive antibodies against glycan-modulated neutralizing V3 epitopes of HIV-1 by immune complex vaccines.  

PubMed

HIV-1 envelope gp120 is the target for neutralizing antibodies (NAbs) against the virus. Various approaches have been explored to improve immunogenicity of broadly neutralizing epitopes on this antigen with limited success. We previously demonstrated that immunogenicity of gp120 and especially its V3 epitopes was enhanced when gp120 was co-administered as immune-complex vaccines with monoclonal antibodies (mAb) to the CD4-binding site (CD4bs). To define the mechanisms by which immune complexes influence V3 immunogenicity, we compared gp120 complexed with mAbs specific for the C2 region (1006-30), the V2 loop (2158), or the CD4bs (654), and found that the gp120/654 and gp120/2158 complexes elicited anti-V3 NAbs, but the gp120/654 complex was the most effective. gp120 complexed with 654 F(ab')2 was as potent, indicating that V3 immunogenicity is determined by the specificity of the mAb's Fab fragment used to form the complexes. Importantly, the gp120/654 complex not only induced anti-gp120 antibodies (Abs) to higher titers, but also of greater avidity. The Abs were cross-reactive with V3 peptides from most subtype B and some subtype C isolates. Neutralization was detected only against Tier-1 HIV-1 pseudoviruses, while Tier-2 viruses, including the homologous JRFL strain, were not neutralized. However, JRFL produced in the presence of a mannosidase inhibitor was sensitive to anti-V3 NAbs in the immune sera. These results demonstrate that the gp120/654 complex is a potent immunogen for eliciting cross-reactive functional NAbs against V3 epitopes, of which exposure is determined by the specific compositions of glycans shrouding the HIV-1 envelope glycoproteins. PMID:24051158

Kumar, Rajnish; Tuen, Michael; Liu, Jianping; Nàdas, Arthur; Pan, Ruimin; Kong, Xiangpeng; Hioe, Catarina E

2013-09-16

177

Broad control of disulfide stability through microenvironmental effects and analysis in complex redox environments.  

PubMed

Disulfide bonds stabilize the tertiary- and quaternary structure of proteins. In addition, they can be used to engineer redox-sensitive (bio)materials and drug-delivery systems. Many of these applications require control of the stability of the disulfide bond. It has recently been shown that the charged microenvironment of the disulfide can be used to alter their stability by ?3 orders of magnitude in a predictable and finely tunable manner at acidic pH. The aim of this work is to extend these findings to physiological pH and to demonstrate the validity of this approach in complex redox milieu. Disulfide microenvironments were manipulated synergistically with steric hindrance herein to control disulfide bond stability over ?3 orders of magnitude at neutral pH. Control of disulfide stability through microenvironmental effects could also be observed in complex redox buffers (including serum) and in the presence of cells. Such fine and predictable control of disulfide properties is not achievable using other existing approaches. These findings provide easily implementable and general tools for controlling the responsiveness of biomaterials and drug delivery systems toward various local endogenous redox environments. PMID:23738500

Wu, Chuanliu; Wang, Shuo; Brülisauer, Lorine; Leroux, Jean-Christophe; Gauthier, Marc A

2013-06-18

178

Variability in quasar broad absorption line outflows - I. Trends in the short-term versus long-term data  

NASA Astrophysics Data System (ADS)

Broad absorption lines (BALs) in quasar spectra identify high-velocity outflows that likely exist in all quasars and could play a major role in feedback to galaxy evolution. The variability of BALs can help us understand the structure, evolution and basic physical properties of the outflows. Here we report on our first results from an ongoing BAL monitoring campaign of a sample of 24 luminous quasars at redshifts 1.2 < z < 2.9, focusing on C IV?1549 BAL variability in two different time intervals: 4-9 months (short term) and 3.8-7.7 yr (long term) in the quasar rest frame. We find that 39 per cent (7/18) of the quasars varied in the short-term data, whereas 65 per cent (15/23) varied in the long-term data, with a larger typical change in strength in the long-term data. The variability occurs typically in only portions of the BAL troughs. The components at higher outflow velocities are more likely to vary than those at lower velocities, and weaker BALs are more likely to vary than stronger BALs. The fractional change in BAL strength correlates inversely with the strength of the BAL feature, but does not correlate with the outflow velocity. Both the short-term and long-term data indicate the same trends. The observed behaviour is most readily understood as a result of the movement of clouds across the continuum source. If the crossing speeds do not exceed the local Keplerian velocity, then the observed short-term variations imply that the absorbers are <6 pc from the central quasar.

Capellupo, D. M.; Hamann, F.; Shields, J. C.; Rodríguez Hidalgo, P.; Barlow, T. A.

2011-05-01

179

THE LICK AGN MONITORING PROJECT 2011: DYNAMICAL MODELING OF THE BROAD-LINE REGION IN Mrk 50  

SciTech Connect

We present dynamical modeling of the broad-line region (BLR) in the Seyfert 1 galaxy Mrk 50 using reverberation mapping data taken as part of the Lick AGN Monitoring Project (LAMP) 2011. We model the reverberation mapping data directly, constraining the geometry and kinematics of the BLR, as well as deriving a black hole mass estimate that does not depend on a normalizing factor or virial coefficient. We find that the geometry of the BLR in Mrk 50 is a nearly face-on thick disk, with a mean radius of 9.6{sup +1.2}{sub -0.9} light days, a width of the BLR of 6.9{sup +1.2}{sub -1.1} light days, and a disk opening angle of 25 {+-} 10 deg above the plane. We also constrain the inclination angle to be 9{sup +7}{sub -5} deg, close to face-on. Finally, the black hole mass of Mrk 50 is inferred to be log{sub 10}(M{sub BH}/M{sub Sun }) = 7.57{sup +0.44}{sub -0.27}. By comparison to the virial black hole mass estimate from traditional reverberation mapping analysis, we find the normalizing constant (virial coefficient) to be log{sub 10} f = 0.78{sup +0.44}{sub -0.27}, consistent with the commonly adopted mean value of 0.74 based on aligning the M{sub BH}-{sigma}* relation for active galactic nuclei and quiescent galaxies. While our dynamical model includes the possibility of a net inflow or outflow in the BLR, we cannot distinguish between these two scenarios.

Pancoast, Anna; Brewer, Brendon J.; Treu, Tommaso; Bennert, Vardha N.; Sand, David J. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Barth, Aaron J.; Cooper, Michael C. [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697-4575 (United States); Canalizo, Gabriela [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Filippenko, Alexei V.; Li, Weidong; Cenko, S. Bradley; Clubb, Kelsey I. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Gates, Elinor L. [Lick Observatory, P.O. Box 85, Mount Hamilton, CA 95140 (United States); Greene, Jenny E. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Malkan, Matthew A. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States); Stern, Daniel; Assef, Roberto J. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Boulevard, Pasadena, CA 91109 (United States); Woo, Jong-Hak [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Bae, Hyun-Jin [Department of Astronomy and Center for Galaxy Evolution Research, Yonsei University, Seoul 120-749 (Korea, Republic of); Buehler, Tabitha, E-mail: pancoast@physics.ucsb.edu [Department of Physics and Astronomy, N283 ESC, Brigham Young University, Provo, UT 84602-4360 (United States); and others

2012-07-20

180

X-ray and optical properties of broad absorption line quasars in the Canada-France-Hawaii Telescope Legacy Survey  

NASA Astrophysics Data System (ADS)

We study the X-ray and optical properties of 16 broad absorption line (BAL) quasars detected in a ?3 deg2 region common to the wide synoptic (W-1) component of the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) and the XMM Large Scale Structure Survey (XMM-LSS). The BAL fraction is found to be 10 per cent in the full sample, 7 per cent for the optical colour-selected quasi-stellar objects (QSOs) and as high as 33 per cent if we consider QSOs selected from their infrared colours. The X-ray-detected non-BAL and BAL quasars have a mean observed X-ray-to-optical spectral slope (?ox) of -1.47 ± 0.13 and -1.66 ± 0.17, respectively. We also find that the BAL QSOs have ?ox systematically smaller than what is expected from the relationship between optical luminosity and ?ox as derived from our sample. Based on this, we show, as already reported in the literature for quasars with high optical luminosities, that our new sample of BAL QSOs has X-ray luminosity a factor of 3 smaller than what has been found for non-BAL QSOs with similar optical luminosities. Comparison of hardness ratios of the BAL and non-BAL QSOs suggests a possible soft X-ray weakness of BAL QSOs. Combining our sample, of relatively fainter QSOs, with others from the literature we show that larger balnicity index (BI) and maximum velocity (Vmax) of the C IV absorption are correlated with steeper X-ray-to-optical spectral index. We argue that this is most likely a consequence of the existence of a lower envelope in the distribution of BI (or Vmax) values versus optical luminosity. Our results thus show that the previously known X-ray weakness of BAL QSOs extends to lower optical luminosities as well.

Stalin, C. S.; Srianand, R.; Petitjean, P.

2011-05-01

181

STAR FORMATION IN SELF-GRAVITATING DISKS IN ACTIVE GALACTIC NUCLEI. I. METALLICITY GRADIENTS IN BROAD-LINE REGIONS  

SciTech Connect

It has been suggested that the high metallicity generally observed in active galactic nuclei (AGNs) and quasars originates from ongoing star formation in the self-gravitating part of accretion disks around supermassive black holes (SMBHs). We designate this region as the star-forming (SF) disk, in which metals are produced from supernova explosions (SNexp) while at the same time inflows are driven by SNexp-excited turbulent viscosity to accrete onto the SMBHs. In this paper, an equation of metallicity governed by SNexp and radial advection is established to describe the metal distribution and evolution in the SF disk. We find that the metal abundance is enriched at different rates at different positions in the disk, and that a metallicity gradient is set up that evolves for steady-state AGNs. Metallicity as an integrated physical parameter can be used as a probe of the SF disk age during one episode of SMBH activity. In the SF disk, evaporation of molecular clouds heated by SNexp blast waves unavoidably forms hot gas. This heating is eventually balanced by the cooling of the hot gas, but we show that the hot gas will escape from the SF disk before being cooled, and diffuse into the broad-line regions (BLRs) forming with a typical rate of {approx}1 M{sub sun} yr{sup -1}. The diffusion of hot gas from an SF disk depends on ongoing star formation, leading to the metallicity gradients in BLR observed in AGNs. We discuss this and other observable consequences of this scenario.

Wang Jianmin; Ge Junqiang; Hu Chen; Li Yanrng; Xiang Fei; Zhang Shu [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquan Road, Beijing 100049 (China); Baldwin, Jack A. [Physics and Astronomy Department, 3270 Biomedical Physical Sciences Building, Michigan State University, East Lansing, MI 48824 (United States); Ferland, Gary J. [Department of Physics and Astronomy, 177 Chemistry/Physics Building, University of Kentucky, Lexington, KY 40506 (United States); Yan Changshuo, E-mail: wangjm@mail.ihep.ac.cn [National Astronomical Observatories of China, Chinese Academy of Sciences, 20A Datun Road, Beijing 100020 (China)

2011-09-20

182

Herschel-ATLAS: the far-infrared properties and star formation rates of broad absorption line quasi-stellar objects  

NASA Astrophysics Data System (ADS)

We have used data from the Herschel Astrophysical Terahertz Large-Area Survey (H-ATLAS) at 250, 350 and 500 ?m to determine the far-infrared (FIR) properties of 50 broad absorption line quasars (BAL QSOs). Our sample contains 49 high-ionization BAL QSOs (HiBALs) and one low-ionization BAL QSO (LoBAL) which are compared against a sample of 329 non-BAL QSOs. These samples are matched over the redshift range 1.5 ? z < 2.3 and in absolute i-band magnitude over the range -28 ? Mi ? -24. Of these, three BAL QSOs (HiBALs) and 27 non-BAL QSOs are detected at the >5 ? level. We calculate star formation rates (SFRs) for our individually detected HiBAL QSOs and the non-detected LoBAL QSO as well as average SFRs for the BAL and non-BAL QSO samples based on stacking the Herschel data. We find no difference between the HiBAL and non-BAL QSO samples in the FIR, even when separated based on differing BAL QSO classifications. Using Mrk 231 as a template, the weighted mean SFR is estimated to be ?240 ± 21 M? yr-1 for the full sample, although this figure should be treated as an upper limit if active galactic nucleus (AGN)-heated dust makes a contribution to the FIR emission. Despite tentative claims in the literature, we do not find a dependence of C IV equivalent width on FIR emission, suggesting that the strength of any outflow in these objects is not linked to their FIR output. These results strongly suggest that BAL QSOs (more specifically HiBALs) can be accommodated within a simple AGN unified scheme in which our line of sight to the nucleus intersects outflowing material. Models in which HiBALs are caught towards the end of a period of enhanced spheroid and black hole growth, during which a wind terminates the star formation activity, are not supported by the observed FIR properties. The Herschel-ATLAS is a project with Herschel, which is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. The H-ATLAS website is http://www/h-atlas.org/.

Cao Orjales, J. M.; Stevens, J. A.; Jarvis, M. J.; Smith, D. J. B.; Hardcastle, M. J.; Auld, R.; Baes, M.; Cava, A.; Clements, D. L.; Cooray, A.; Coppin, K.; Dariush, A.; De Zotti, G.; Dunne, L.; Dye, S.; Eales, S.; Hopwood, R.; Hoyos, C.; Ibar, E.; Ivison, R. J.; Maddox, S.; Page, M. J.; Valiante, E.

2012-12-01

183

Purification and preliminary characterization of mitochondrial complex I (NADH: ubiquinone reductase) from broad bean (Vicia faba L.).  

PubMed Central

NADH:ubiquinone reductase (EC 1.6.19.3), or complex I, was isolated from broad bean (Vicia faba L.) mitochondria. Osmotic shock and sequential treatment with 0.2% (v/v) Triton X-100 and 0.5% (w/v) [3-cholamidopropyl)dimethylammonio]-1-propanesulfate (CHAPS) removed all other NADH dehydrogenase activities. Complex I was solubilized in the presence of 4% Triton X-100 and then purified by sucrose-gradient centrifugation in the presence of the same detergent. The second purification step was hydroxylapatite chromatography. Substitution of CHAPS for Triton X-100 helped remove contaminants such as ATPase. The high molecular mass complex is composed of at least 26 subunits with molecular masses ranging from 6000 to 75,000 kD. The purified complex I reduced ferricyanide and ubiquinone analogs but not cytochrome c. NADPH could not substitute for NADH as an electron donor. The KM for NADH was 20 microM at the optimum pH of 8.0. The NH2-terminal sequence of several subunits was determined, revealing the ambiguous nature of the 42-kD subunit.

Leterme, S; Boutry, M

1993-01-01

184

Contrasting phylogeographic histories between broadly sympatric topminnows in the Fundulus notatus species complex.  

PubMed

Sympatrically distributed closely related species provide opportunities for studying evolutionary patterns of diversification. Such studies must account for historical contingencies in interpreting contemporary patterns of variation. Topminnows in the Fundulus notatus species complex are distributed sympatrically across much of the southern and Midwestern United States. Throughout most of their ranges F. olivaceus is often found in headwater stream habitats, and F. notatus is more typically distributed along the margins of larger river habitats. However, in some drainages, ecological associations of the respective species are reversed, with F. notatus populations isolated in headwater streams and F. olivaceus in downstream river habitats. Phylogeographic analyses of AFLP marker and multi-locus sequence data detected historical isolation in F. notatus consistent with pre-Pleistocene drainage patterns. Four F. notatus clades corresponded to (i) the Western Gulf Slope, (ii) the southwestern Ouachita Highlands, (iii) the Mobile Basin, and (iv) central Coastal Plain and Mississippi River Basin. In contrast, a relative lack of range-wide geographic structure in F. olivaceus is consistent with recent range expansion over much of the same geographic area. The southwestern Ouachita Highlands and Mobile Basin F. notatus clades corresponded to regions where ecological associations between the two species are reversed, providing evidence of the independent evolution of variation in contemporary habitat associations. Fundulus olivaceus from several drainages demonstrated introgression of mitochondrial DNA from F. notatus, but none of the sites in this study included individuals with hybrid ancestry in their nuclear genome. Phylogenetic analyses that included only nuclear loci supported the reciprocal monophyly of F. notatus, F. olivaceus and a third narrowly endemic species, Fundulus euryzonus, and supported a sister relationship between F. olivaceus and F. euryzonus. PMID:23887036

Duvernell, David D; Meier, Stephanie L; Schaefer, Jacob F; Kreiser, Brian R

2013-07-22

185

Interactions between tannins and proteins isolated from broad bean seeds ( Vicia faba Major) yield soluble and non-soluble complexes  

Microsoft Academic Search

The binding of tannin fraction to protein fractions isolated from broad bean seeds was studied by precipitating potential\\u000a and fluorescence quenching methods. The tannin fraction with high proanthocyanidins content was isolated from broad bean coats.\\u000a Storage proteins of broad bean, 11S, 7S, and 2S, were isolated from broad bean cotyledons and purified. Gelatin, BSA, as well\\u000a as broad bean 2S

Magdalena Karama?; Kamila Penkacik; Anna Urbalewicz; Ryszard Amarowicz

186

Crystal Structure of An FIV/HIV Chimeric Protease Complexed With the Broad-Based Inhibitor, TL-3  

SciTech Connect

We have obtained the 1.7 angstrom crystal structure of FIV protease (PR) in which 12 critical residues around the active site have been substituted with the structurally equivalent residues of HIV PR (12X FIV PR). The chimeric PR was crystallized in complex with the broad-based inhibitor TL-3, which inhibits wild type FIV and HIV PRs, as well as 12X FIV PR and several drug-resistant HIV mutants [1-4]. Biochemical analyses have demonstrated that TL-3 inhibits these PRs in the order HIV PR > 12X FIV PR > FIV PR, with Ki values of 1.5 nM, 10 nM, and 41 nM, respectively [2-4]. Comparison of the crystal structures of the TL-3 complexes of 12X FIV and wild-typeFIV PR revealed the formation of additional van der Waals interactions between the enzyme inhibitor in the mutant PR. The 12X FIV PR retained the hydrogen bonding interactions between residues in the flap regions and active site involving the enzyme and the TL-3 inhibitor in comparison to both FIV PR and HIV PR. However, the flap regions of the 12X FIV PR more closely resemble those of HIV PR, having gained several stabilizing intra-flap interactions not present in wild type FIV PR. These findings offer a structural explanation for the observed inhibitor/substrate binding properties of the chimeric PR.

Heaslet, H.; Lin, Y.-C.; Tam, K.; Torbett, B.E.; Elder, J.E.; Stout, C.D.; /Pfizer Global Res. Devel. /Scripps Res. Inst.

2007-07-09

187

Relativistic Plasma as the Dominant Source of the Optical Continuum Emission in the Broad-Line Radio Galaxy 3C 120  

NASA Astrophysics Data System (ADS)

We report a relation between radio emission in the inner jet of the Seyfert galaxy 3C 120 and optical continuum emission in this galaxy. Combining the optical variability data with multi-epoch high-resolution very long baseline interferometry observations reveals that an optical flare rises when a superluminal component emerges into the jet, and its maxima is related to the passage of such component through the location of a stationary feature at a distance of ?1.3 pc from the jet origin. This indicates that a significant fraction of the optical continuum produced in 3C 120 is non-thermal, and it can ionize material in a sub-relativistic wind or outflow. We discuss implications of this finding for the ionization and structure of the broad emission line region, as well as for the use of broad emission lines for determining black hole masses in radio-loud active galactic nucleus.

León-Tavares, J.; Lobanov, A. P.; Chavushyan, V. H.; Arshakian, T. G.; Doroshenko, V. T.; Sergeev, S. G.; Efimov, Y. S.; Nazarov, S. V.

2010-05-01

188

On Time Variability and Other Complications in Studying the UV Broad Absorption Lines of Quasars: Results from Numerical Simulations of Radiation Driven Disk Winds.  

NASA Astrophysics Data System (ADS)

We review the main results from axisymmetric, time-dependent hydrodynamical simulations of radiation driven disk winds in AGN. We illustrate the capability of such simulations to provide useful insights into the three domains of observational astronomy: spectroscopy, time-variability, and imaging. Specifically, the synthetic line profiles predicted by the simulations resemble the broad absorption lines observed in quasars. The intrinsically time dependent nature of radiation driven disk winds that have been predicted by the simulations can be supported by a growing number of the observed dramatic variability in the UV absorption lines. And finally, the intensity maps predicted by the simulations give physical and geometrical justification to the phenomenologically deduced fact that a proper interpretation of the observed line absorption requires the wind covering factor to be considered as being partial, inhomogeneous, and velocity dependent.

Proga, D.; Rodriguez-Hidalgo, P.; Hamann, F.

2012-08-01

189

Genetic analysis of broad spectrum resistance to potyviruses using doubled haploid lines of pepper (Capsicum annuum L.)  

Microsoft Academic Search

Genetic analysis of resistance to PVY in androgenetic doubled haploid lines, F1, F2 and backcross progenies of the Mexican pepper line, CM 334 (Capsicum annuum L.), was performed. Three reaction types were observed when seedlings were inoculated with several PVY strains of different pathotypes and with an American PeMV strain. Resistant genotypes never showed systemic symptoms although some individuals sporadically

Catherine Dogimont; Alain Palloix; Anne-Marie Daubze; Georges Marchoux; Kashay Gebre Selassie; E. Pochard

1996-01-01

190

Melon RNA interference (RNAi) lines silenced for Cm-eIF4E show broad virus resistance.  

PubMed

Efficient and sustainable control of plant viruses may be achieved using genetically resistant crop varieties, although resistance genes are not always available for each pathogen; in this regard, the identification of new genes that are able to confer broad-spectrum and durable resistance is highly desirable. Recently, the cloning and characterization of recessive resistance genes from different plant species has pointed towards eukaryotic translation initiation factors (eIF) of the 4E family as factors required for the multiplication of many different viruses. Thus, we hypothesized that eIF4E may control the susceptibility of melon (Cucumis melo L.) to a broad range of viruses. To test this hypothesis, Cm-eIF4E knockdown melon plants were generated by the transformation of explants with a construct that was designed to induce the silencing of this gene, and the plants from T2 generations were genetically and phenotypically characterized. In transformed plants, Cm-eIF4E was specifically silenced, as identified by the decreased accumulation of Cm-eIF4E mRNA and the appearance of small interfering RNAs derived from the transgene, whereas the Cm-eIF(iso)4E mRNA levels remained unaffected. We challenged these transgenic melon plants with eight agronomically important melon-infecting viruses, and identified that they were resistant to Cucumber vein yellowing virus (CVYV), Melon necrotic spot virus (MNSV), Moroccan watermelon mosaic virus (MWMV) and Zucchini yellow mosaic virus (ZYMV), indicating that Cm-eIF4E controls melon susceptibility to these four viruses. Therefore, Cm-eIF4E is an efficient target for the identification of new resistance alleles able to confer broad-spectrum virus resistance in melon. PMID:22309030

Rodríguez-Hernández, Ana M; Gosalvez, Blanca; Sempere, Raquel N; Burgos, Lorenzo; Aranda, Miguel A; Truniger, Verónica

2012-02-06

191

TWO-COMPONENT STRUCTURE OF THE H{beta} BROAD-LINE REGION IN QUASARS. I. EVIDENCE FROM SPECTRAL PRINCIPAL COMPONENT ANALYSIS  

SciTech Connect

We report on a spectral principal component analysis (SPCA) of a sample of 816 quasars, selected to have small Fe II velocity shifts with spectral coverage in the rest wavelength range 3500-5500 A. The sample is explicitly designed to mitigate spurious effects on SPCA induced by Fe II velocity shifts. We improve the algorithm of SPCA in the literature and introduce a new quantity, the fractional-contribution spectrum, that effectively identifies the emission features encoded in each eigenspectrum. The first eigenspectrum clearly records the power-law continuum and very broad Balmer emission lines. Narrow emission lines dominate the second eigenspectrum. The third eigenspectrum represents the Fe II emission and a component of the Balmer lines with kinematically similar intermediate-velocity widths. Correlations between the weights of the eigenspectra and parametric measurements of line strength and continuum slope confirm the above interpretation for the eigenspectra. Monte Carlo simulations demonstrate the validity of our method to recognize cross talk in SPCA and firmly rule out a single-component model for broad H{beta}. We also present the results of SPCA for four other samples that contain quasars in bins of larger Fe II velocity shift; similar eigenspectra are obtained. We propose that the H{beta}-emitting region has two kinematically distinct components: one with very large velocities whose strength correlates with the continuum shape and another with more modest, intermediate velocities that is closely coupled to the gas that gives rise to Fe II emission.

Hu Chen; Wang Jianmin [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquan Road, Beijing 100049 (China); Ho, Luis C. [The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Ferland, Gary J.; Wang Ye [Department of Physics and Astronomy, 177 Chemistry/Physics Building, University of Kentucky, Lexington, KY 40506 (United States); Baldwin, Jack A., E-mail: huc@ihep.ac.cn [Department of Physics and Astronomy, 3270 Biomedical Physical Sciences Building, Michigan State University, East Lansing, MI 48824 (United States)

2012-12-01

192

The broad emission-line region: the confluence of the outer accretion disc with the inner edge of the dusty torus  

NASA Astrophysics Data System (ADS)

We have investigated the observational characteristics of a class of broad emission line region (BLR) geometries that connect the outer accretion disc with the inner edge of the dusty toroidal obscuring region (TOR). We suggest that the BLR consists of photoionized gas of densities which allow for efficient cooling by ultraviolet (UV)/optical emission lines and of incident continuum fluxes which discourage the formation of grains, and that such gas occupies the range of distance and scale height between the continuum-emitting accretion disc and the dusty TOR. As a first approximation, we assume a population of clouds illuminated by ionizing photons from the central source, with the scale height of the illuminated clouds growing with increasing radial distance, forming an effective surface of a 'bowl'. Observer lines of sight which peer into the bowl lead to a Type 1 active galactic nuclei (AGN) spectrum. We assume that the gas dynamics are dominated by gravity, and we include in this model the effects of transverse Doppler shift (TDS), gravitational redshift (GR) and scale-height-dependent macroturbulence. Our simple model reproduces many of the commonly observed phenomena associated with the central regions of AGN, including (i) the shorter than expected continuum-dust delays (geometry), (ii) the absence of response in the core of the optical recombination lines on short time-scales (geometry/photoionization), (iii) an enhanced redwing response on short time-scales (GR and TDS), (iv) the observed differences between the delays for high- and low-ionization lines (photoionization), (v) identifying one of the possible primary contributors to the observed line widths for near face-on systems even for purely transverse motion (GR and TDS), (vi) a mechanism responsible for producing Lorentzian profiles (especially in the Balmer and Mg II emission lines) in low-inclination systems (turbulence), (vii) the absence of significant continuum-emission-line delays between the line wings and line core (turbulence; such time delays are weak for virialized motion, and turbulence serves to reduce any differences which may be present), (viii) associating the boundary between population A and population B sources as the cross-over between inclination-dependent (population A) and inclination-independent (population B) line profiles (GR+TDS), (ix) a partial explanation of the differences between the emission-line profiles, here explained in terms of their line formation radius (photoionization and/or turbulence) and (x) the unexpectedly high (but necessary) covering fractions (geometry). A key motivation of this work was to reveal the physical underpinnings of the reported measurements of supermassive black hole (SMBH) masses and their uncertainties. We have driven our model with simulated continuum light curves in order to determine the virial scale factor f from measurements of the simulated continuum-emission-line delay, and the width (fwhm, ?l) and shape (fwhm / ?l) of the rms and mean line profiles for the energetically more important broad UV and optical recombination lines used in SMBH mass determinations. We thus attempt to illuminate the physical dependencies of the empirically determined value of f. We find that SMBH masses derived from measurements of the fwhm of the mean and rms profiles show the closest correspondence between the emission lines in a single object, even though the emission-line fwhm is a more biased mass indicator with respect to inclination. The predicted large discrepancies in the SMBH mass estimates between emission lines at low inclination, as derived using ?l, we suggest may be used as a means of identifying near face-on systems. Our general results do not depend on specific choices in the simplifying assumptions, but are in fact generic properties of BLR geometries with axial symmetry that span a substantial range in radially increasing scale height supported by turbulence, which then merge into the inner dusty TOR.

Goad, M. R.; Korista, K. T.; Ruff, A. J.

2012-11-01

193

A Survey of X-Ray Variability in Seyfert 1 Galaxies with XMM-Newton to study the soft excess and the broad Fe lines  

NASA Astrophysics Data System (ADS)

The nature of the soft excess and the presence of the broad Fe lines is still nowadays highly debated because the different absorption/emission models are degenerate. Spectral variability studies have the potential to break this degeneracy. I will present the results of a spectral variability RMS survey of the 36 brightest type 1 Seyfert galaxies observed by XMM-Newton for more than 30 ks. More than 80 as already measured, on longer timescales, with RXTE (Markowitz et al. 2004). About half of the sample show lower variability in the soft energy band, indicating that the emission from the soft excess is more stable than the one of the continuum. While the other sources show a soft excess that is as variable as the continuum. About half of the sample do not show an excess of variability where the warm absorber component imprints its stronger features, suggesting that for these sources the soft excess is not produced by a relativistic absorbing wind. In a few bright and well exposed sources it has been possible to measure an excess of variability at the energy of the broad component of the Fe K line, in agreement with the broad emission line interpretation. For the sources where more than one observation was available the stability of the shape of the RMS spectrum has been investigated. Moreover, it will be presented the results of the computation of the excess variance of all the radio quiet type 1 AGN of the XMM-Newton database. The relations between variability, black hole mass, accretion rate and luminosity are investigated and their scatter measured.

Ponti, Gabriele

194

Black Hole Mass and Eddington Ratio Distribution Functions of X-Ray-selected Broad-line AGNs at z ~ 1.4 in the Subaru XMM-Newton Deep Field  

NASA Astrophysics Data System (ADS)

In order to investigate the growth of supermassive black holes (SMBHs), we construct the black hole mass function (BHMF) and Eddington ratio distribution function (ERDF) of X-ray-selected broad-line active galactic nuclei (AGNs) at z ~ 1.4 in the Subaru XMM-Newton Deep Survey (SXDS) field. A significant part of the accretion growth of SMBHs is thought to take place in this redshift range. Black hole masses of X-ray-selected broad-line AGNs are estimated using the width of the broad Mg II line and 3000 Å monochromatic luminosity. We supplement the Mg II FWHM values with the H? FWHM obtained from our NIR spectroscopic survey. Using the black hole masses of broad-line AGNs at redshifts between 1.18 and 1.68, the binned broad-line AGN BHMFs and ERDFs are calculated using the V max method. To properly account for selection effects that impact the binned estimates, we derive the corrected broad-line AGN BHMFs and ERDFs by applying the maximum likelihood method, assuming that the ERDF is constant regardless of the black hole mass. We do not correct for the non-negligible uncertainties in virial BH mass estimates. If we compare the corrected broad-line AGN BHMF with that in the local universe, then the corrected BHMF at z = 1.4 has a higher number density above 108 M ? but a lower number density below that mass range. The evolution may be indicative of a downsizing trend of accretion activity among the SMBH population. The evolution of broad-line AGN ERDFs from z = 1.4 to 0 indicates that the fraction of broad-line AGNs with accretion rates close to the Eddington limit is higher at higher redshifts. Based in part on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

Nobuta, K.; Akiyama, M.; Ueda, Y.; Watson, M. G.; Silverman, J.; Hiroi, K.; Ohta, K.; Iwamuro, F.; Yabe, K.; Tamura, N.; Moritani, Y.; Sumiyoshi, M.; Takato, N.; Kimura, M.; Maihara, T.; Dalton, G.; Lewis, I.; Bonfield, D.; Lee, H.; Curtis-Lake, E.; Macaulay, E.; Clarke, F.; Sekiguchi, K.; Simpson, C.; Croom, S.; Ouchi, M.; Hanami, H.; Yamada, T.

2012-12-01

195

BLACK HOLE MASS AND EDDINGTON RATIO DISTRIBUTION FUNCTIONS OF X-RAY-SELECTED BROAD-LINE AGNs AT z {approx} 1.4 IN THE SUBARU XMM-NEWTON DEEP FIELD  

SciTech Connect

In order to investigate the growth of supermassive black holes (SMBHs), we construct the black hole mass function (BHMF) and Eddington ratio distribution function (ERDF) of X-ray-selected broad-line active galactic nuclei (AGNs) at z {approx} 1.4 in the Subaru XMM-Newton Deep Survey (SXDS) field. A significant part of the accretion growth of SMBHs is thought to take place in this redshift range. Black hole masses of X-ray-selected broad-line AGNs are estimated using the width of the broad Mg II line and 3000 A monochromatic luminosity. We supplement the Mg II FWHM values with the H{alpha} FWHM obtained from our NIR spectroscopic survey. Using the black hole masses of broad-line AGNs at redshifts between 1.18 and 1.68, the binned broad-line AGN BHMFs and ERDFs are calculated using the V{sub max} method. To properly account for selection effects that impact the binned estimates, we derive the corrected broad-line AGN BHMFs and ERDFs by applying the maximum likelihood method, assuming that the ERDF is constant regardless of the black hole mass. We do not correct for the non-negligible uncertainties in virial BH mass estimates. If we compare the corrected broad-line AGN BHMF with that in the local universe, then the corrected BHMF at z = 1.4 has a higher number density above 10{sup 8} M{sub Sun} but a lower number density below that mass range. The evolution may be indicative of a downsizing trend of accretion activity among the SMBH population. The evolution of broad-line AGN ERDFs from z = 1.4 to 0 indicates that the fraction of broad-line AGNs with accretion rates close to the Eddington limit is higher at higher redshifts.

Nobuta, K.; Akiyama, M. [Astronomical Institute, Tohoku University, 6-3 Aramaki, Aoba-ku, Sendai 980-8578 (Japan); Ueda, Y.; Hiroi, K.; Ohta, K.; Iwamuro, F.; Yabe, K.; Moritani, Y.; Sumiyoshi, M.; Maihara, T. [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Watson, M. G. [XROA Group, Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Silverman, J.; Tamura, N.; Kimura, M. [Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa 277-8583 (Japan); Takato, N. [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Dalton, G.; Lewis, I.; Bonfield, D.; Lee, H.; Curtis-Lake, E., E-mail: akiyama@astr.tohoku.ac.jp [Department of Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); and others

2012-12-20

196

The size of the X-ray emitting region in SWIFT J2127.4+5654 via a broad line region cloud X-ray eclipse  

NASA Astrophysics Data System (ADS)

We present results obtained from the time-resolved X-ray spectral analysis of the Narrow-Line-Seyfert 1 galaxy SWIFT J2127.4+5654 during a ˜130 ks XMM-Newton observation. We reveal large spectral variations, especially during the first ˜90 ks of the XMM-Newton exposure. The spectral variability can be attributed to a partial eclipse of the X-ray source by an intervening low-ionization/cold absorbing structure (cloud) with column density NH = 2.0^{+0.2}_{-0.3}× 10^{22} cm-2 which gradually covers and then uncovers the X-ray emitting region with covering fraction ranging from zero to ˜43 per cent. Our analysis enables us to constrain the size, number density and location of the absorbing cloud with good accuracy. We infer a cloud size (diameter) of Dc ? 1.5 × 1013 cm, corresponding to a density of nc ? 1.5 × 109 cm-3 at a distance of Rc ? 4.3 × 1016 cm from the central black hole. All of the inferred quantities concur to identify the absorbing structure with one single cloud associated with the broad line region of SWIFT J2127.4+5654. We are also able to constrain the X-ray emitting region size (diameter) to be Ds ? 2.3 × 1013 cm which, assuming the black hole mass estimated from single-epoch optical spectroscopy (1.5 × 107 M?), translates into Ds ? 10.5 gravitational radii (rg) with larger sizes (in rg) being associated with smaller black hole masses, and vice versa. We also confirm the presence of a relativistically distorted reflection component off the inner accretion disc giving rise to a broad relativistic Fe K emission line and small soft excess (small because of the high Galactic column density), supporting the measurement of an intermediate black hole spin in SWIFT J2127.4+5654 that was obtained from a previous Suzaku observation.

Sanfrutos, M.; Miniutti, G.; Agís-González, B.; Fabian, A. C.; Miller, J. M.; Panessa, F.; Zoghbi, A.

2013-10-01

197

XMM-Newton first X-ray detection of the low-ionization broad absorption line quasar PG 1700+518  

NASA Astrophysics Data System (ADS)

We report the first high-energy detection of PG 1700+518, a well-known low-ionization broad absorption line quasar (quasi-stellar object, QSO). Due to previous X-ray non-detection, it was classified as soft X-ray weak QSO. We observed PG 1700+518 with XMM-Newton for about 60 ks divided in three exposures. The spectrum below 2 keV is very steep, ?˜ 2.4-3.8, while at higher energies the extremely flat emission (photon index ?˜ 0.15, when modelled with a power law) suggests the presence of strong absorption (NH, pl˜ 2 × 1023 cm-2, ? fixed to 1.8) or a reflection-dominated continuum. The broad-band flux is consistent with previous non-detection. Simultaneous European Photon Imaging Camera (EPIC) and Optical Monitor (OM) data confirm its X-ray weakness (observed?ox˜-2.2). The level of obscuration derived from the X-ray spectra of PG 1700+518 cannot explain its soft X-ray nuclear weakness unless a column density of NH? 2 × 1024 cm-2 is present.

Ballo, L.; Piconcelli, E.; Vignali, C.; Schartel, N.

2011-08-01

198

Steps toward determination of the size and structure of the broad-line region in active nuclei. 7: Variability of the optical spectrum of NGC 5548 over years  

NASA Astrophysics Data System (ADS)

We report on the results of a continuation of a large monitoring program of optical spectroscopy of the Seyfert 1 galaxy NGC 5548. The new observations presented here were obtained between 1990 December and 1992 October, and extend the existing database to nearly 1400 days, dating back to 1988 December. The continuum variations are generally smooth and well-resolved, except during the third year of this 4 year project, when the variations were apparently more rapid and of lower amplitude than observed at other times. The broad H(beta) emission line is found to vary in response to the continuum variations with a lag of about 18 days, but with some changes from year to year. The H(beta) transfer functions for each of the 4 yr and for the entire 4 yr database are derived by using a maximum entropy method.

Peterson, B. M.; Berlind, P.; Bertram, R.; Bochkarev, N. G.; Bond, D.; Brotherton, M. S.; Busler, J. R.; Chuvaev, K. K.; Cohen, R. D.; Dietrich, M.; Elvis, M.; Filippenko, A. V.; Foltz, C. B.; Garnavich, P. M.; Ho, L. C.; Horine, E.; Horne, K.; Huchra, J. P.; Kollatschny, W.; Korista, K. T.; Malkan, M. A.; Matheson, T.; Mignoli, M.; Morris, S. L.; Nazarova, L.; Penfold, J.; Peters, J.; Pogge, R. W.; Pronik, V. I.; Rush, B.; Sergeev, S. G.; Shapovalova, A. I.; Shields, J. C.; Stirpe, G. M.; Tokarz, S.; Wagner, R. M.; Weymann, R. J.; White, R. J.; Wilkes, B. J.; Wills, D.; Wills, B. J.; Winge, C.; Younger, P. F.

1994-04-01

199

Broad agents  

Microsoft Academic Search

The Oz project at Carnegie Mellon is developing technology for dramatic virtual worlds. One requirement of such worlds is the presence of broad, though perhaps shallow, agents. To support our needs, we are developing an agent architecture that provides goals and goal directed reactive behavior, emotional state and its effects on behavior, some natural language abilities (especially pragmatics based language

Joseph Bates; Bryan Loyall; W. Scott Reilly

1991-01-01

200

The Demographics of Broad-line Quasars in the Mass-Luminosity Plane. II. Black Hole Mass and Eddington Ratio Functions  

NASA Astrophysics Data System (ADS)

We employ a flexible Bayesian technique to estimate the black hole (BH) mass and Eddington ratio functions for Type 1 (i.e., broad line) quasars from a uniformly selected data set of ~58, 000 quasars from the Sloan Digital Sky Survey (SDSS) DR7. We find that the SDSS becomes significantly incomplete at M BH <~ 3 × 108 M ? or L/L Edd <~ 0.07, and that the number densities of Type 1 quasars continue to increase down to these limits. Both the mass and Eddington ratio functions show evidence of downsizing, with the most massive and highest Eddington ratio BHs experiencing Type 1 quasar phases first, although the Eddington ratio number densities are flat at z < 2. We estimate the maximum Eddington ratio of Type 1 quasars in the observable universe to be L/L Edd ~ 3. Consistent with our results in Shen & Kelly, we do not find statistical evidence for a so-called sub-Eddington boundary in the mass-luminosity plane of broad-line quasars, and demonstrate that such an apparent boundary in the observed distribution can be caused by selection effect and errors in virial BH mass estimates. Based on the typical Eddington ratio in a given mass bin, we estimate growth times for the BHs in Type 1 quasars and find that they are comparable to or longer than the age of the universe, implying an earlier phase of accelerated (i.e., with higher Eddington ratios) and possibly obscured growth. The large masses probed by our sample imply that most of our BHs reside in what are locally early-type galaxies, and we interpret our results within the context of models of self-regulated BH growth.

Kelly, Brandon C.; Shen, Yue

2013-02-01

201

BROAD-LINE REGION PHYSICAL CONDITIONS IN EXTREME POPULATION A QUASARS: A METHOD TO ESTIMATE CENTRAL BLACK HOLE MASS AT HIGH REDSHIFT  

SciTech Connect

We describe a method for estimating physical conditions in the broad-line region (BLR) for a significant subsample of Seyfert 1 nuclei and quasars. Several diagnostic ratios based on intermediate (Al III {lambda}1860, Si III] {lambda}1892) and high (C IV {lambda}1549, Si IV {lambda}1397) ionization lines in the UV spectra of quasars are used to constrain density, ionization, and metallicity of the emitting gas. We apply the method to two extreme Population A quasars-the prototypical NLSy1 I Zw 1 and higher z source SDSS J120144.36+011611.6. Under assumptions of spherical symmetry and pure photoionization we infer BLR physical conditions: low ionization (ionization parameter <10{sup -2}), high density (10{sup 12}-10{sup 13} cm{sup -3}), and significant metal enrichment. Ionization parameter and density can be derived independently for each source with an uncertainty that is less than {+-}0.3 dex. We use the product of density and ionization parameter to estimate the BLR radius and derive an estimation of the virial black hole mass (M{sub BH}). Estimates of M{sub BH} based on the 'photoionization' analysis described in this paper are probably more accurate than those derived from the mass-luminosity correlations widely employed to compute black hole masses for high-redshift quasars.

Negrete, C. Alenka; Dultzin, Deborah [Instituto de Astonomia, Universidad Nacional Autonoma de Mexico (Mexico); Marziani, Paola [INAF, Astronomical Observatory of Padova, I-35122 Padova (Italy); Sulentic, Jack W., E-mail: anegrete@astro.unam.mx, E-mail: deborah@astro.unam.mx, E-mail: paola.marziani@oapd.inaf.it, E-mail: sulentic@iaa.es [Instituto de Astrofisica de Andalucia, E-18008 Granada (Spain)

2012-09-20

202

Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. I - an 8 month campaign of monitoring NGC 5548 with IUE  

Microsoft Academic Search

Emission-line and UV continuum observations of the type I Seyfert galaxy NGC 5548 were carried out for a period of 8 months with the IUE satellite. It was found that both the continuum shape and the line ratios of NGC 5548, while being not unusual for type I Seyfert galaxies, are strongly variable. The UV continuum flux and broad emission

J. Clavel; G. A. Reichert; D. Alloin; D. M. Crenshaw; G. Kriss; J. H. Krolik; M. A. Malkan; H. Netzer; B. M. Peterson; W. Wamsteker; A. Altamore; T. Baribaud; P. Barr; S. Beck; L. Binette; G. E. Bromage; N. Brosch; A. I. Diaz; A. V. Filippenko; K. Fricke; C. M. Gaskell; P. Giommi; I. S. Glass; P. Gondhalekar; R. L. Hackney; J. P. Halpern; D. J. Hutter; S. Joersaeter; A. L. Kinney; W. Kollatschny; A. Koratkar; K. T. Korista; A. Laor; J.-P. Lasota; E. Leibowitz; D. Maoz; P. G. Martin; T. Mazeh; E. J. A. Meurs; A. D. Nair; P. O'Brien; D. Pelat; E. Perez; G. C. Perola; R. L. Ptak; P. Rodriguez-Pascual; E. I. Rosenblatt; A. C. Sadun; M. Santos-Lleo; R. A. Shaw; P. S. Smith; G. M. Stirpe; R. Stoner; W. H. Sun; M.-H. Ulrich; E. van Groningen; W. Zheng

1991-01-01

203

ON THE COSMIC EVOLUTION OF THE SCALING RELATIONS BETWEEN BLACK HOLES AND THEIR HOST GALAXIES: BROAD-LINE ACTIVE GALACTIC NUCLEI IN THE zCOSMOS SURVEY  

SciTech Connect

We report on the measurement of the physical properties (rest-frame K-band luminosity and total stellar mass) of the hosts of 89 broad-line (type-1) active galactic nuclei (AGNs) detected in the zCOSMOS survey in the redshift range 1 < z < 2.2. The unprecedented multi-wavelength coverage of the survey field allows us to disentangle the emission of the host galaxy from that of the nuclear black hole in their spectral energy distributions (SEDs). We derive an estimate of black hole masses through the analysis of the broad Mg II emission lines observed in the medium-resolution spectra taken with VIMOS/VLT as part of the zCOSMOS project. We found that, as compared to the local value, the average black hole to host-galaxy mass ratio appears to evolve positively with redshift, with a best-fit evolution of the form (1+z){sup 0.68+}-{sup 0.12+0.6{sub -0.3}}, where the large asymmetric systematic errors stem from the uncertainties in the choice of initial mass function, in the calibration of the virial relation used to estimate BH masses and in the mean QSO SED adopted. On the other hand, if we consider the observed rest-frame K-band luminosity, objects tend to be brighter, for a given black hole mass, than those on the local M{sub BH}-M{sub K} relation. This fact, together with more indirect evidence from the SED fitting itself, suggests that the AGN hosts are likely actively star-forming galaxies. A thorough analysis of observational biases induced by intrinsic scatter in the scaling relations reinforces the conclusion that an evolution of the M{sub BH}-M{sub *} relation must ensue for actively growing black holes at early times: either its overall normalization, or its intrinsic scatter (or both) appear to increase with redshift. This can be interpreted as signature of either a more rapid growth of supermassive black holes at high redshift, a change of structural properties of AGN hosts at earlier times, or a significant mismatch between the typical growth times of nuclear black holes and host galaxies. In any case, our results provide important clues on the nature of the early co-evolution of black holes and galaxies and challenging tests for models of AGN feedback and self-regulated growth of structures.

Merloni, A. [Excellence Cluster Universe, TUM, Boltzmannstr. 2, 85748, Garching (Germany); Bongiorno, A.; Brusa, M. [Max Planck Institut fuer Extraterrestrische Physik, Giessenbachstr., 85471 Garching (Germany); Bolzonella, M.; Comastri, A.; Gilli, R.; Lusso, E.; Mignoli, M. [INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Civano, F.; Elvis, M.; Hao, H. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Fiore, F. [INAF-Osservatorio Astronomico di Roma, via Frascati 33, Monteporzio (Rm), I00040 (Italy); Jahnke, K. [Max Planck Institut fuer Astronomie, Koenigstuhl 17, Heidelberg, D-69117 (Germany); Koekemoer, A. M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Mainieri, V. [ESO, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Miyaji, T. [Instituto de Astronomia, UNAM-Ensenada, Km 103 Carretera Tijuana-Ensenada, 22860 Ensenada, BC Mexico (United States); Renzini, A. [INAF - Osservatorio Astronomico di Padova, Padova (Italy); Salvato, M. [California Institute of Technology, MC 105-24, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Silverman, J. [Department of Physics, ETH Zurich, CH-8093 Zurich (Switzerland); Trump, J. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

2010-01-01

204

On the Disappearance of the Broad-line Region in Low-luminosity Active Galactic Nuclei: The Role of the Outflows from Advection Dominated Accretion Flows  

NASA Astrophysics Data System (ADS)

The broad-line region (BLR) disappears in many low-luminosity active galactic nuclei (AGNs), the reason of which is still controversial. The BLRs in AGNs are believed to be associated with the outflows from the accretion disks. Most of the low-luminosity AGNs contain advection-dominated accretion flows (ADAFs) which are very hot and have a positive Bernoulli parameter. ADAFs are therefore associated with strong outflows. We estimate the cooling of the outflows from the ADAFs and find that the gases in such hot outflows cannot always be cooled efficiently by bremsstrahlung radiation. The ADAF may co-exist with the standard disk, i.e., the inner ADAF connects to the outer thin accretion disk at radius R d,tr in the sources accreting at slightly lower than the critical rate \\dot{m}_crit (\\dot{m}=\\dot{M}/\\dot{M}_Edd). For the ADAFs with L bol/L Edd >~ 0.001, a secondary small inner cold disk is suggested to co-exist with the ADAF due to the condensation process. We estimate the Compton cooling of the outflow, of which the soft seed photons either come from the outer cold disk or the secondary inner cold disk. It is found that the gas in the outflow far from the ADAF may be efficiently cooled to form BLR clouds due to the soft seed photons emitted from the cold disks, provided the transition radius of the ADAF to the outer cold disk is small [r d,tr = R d,tr/(2GM/c 2) <~ 20] or/and the secondary small cold disk has a luminosity L sd >~ 0.003 L Edd. The BLR clouds can still be formed in the outflows from the outer cold thin disks, if the transition radius r tr is not very large. For the sources with L bol/L Edd <~ 0.001, the inner small cold disk is evaporated completely in the ADAF and the outer thin accretion disk may be suppressed by the ADAF, which leads to the disappearance of the BLR. The physical implications of this scenario on the double-peaked broad-line emitters are also discussed.

Cao, Xinwu

2010-12-01

205

Complex variation of spectral line widths observed in polar corona  

NASA Astrophysics Data System (ADS)

Spectroscopic observations of the solar corona, using high spatial and spectral resolution 25cm coronagraph, at Norikura observatory, were made on large number of days during 2004 at the mid latitude and polar coronal regions. We have analyzed several raster scans that cover mid and high latitude regions on the off-limb corona in four bright emission lines of iron, namely, [Fe X] 6374 Å, [Fe XI]~7892~Å, [Fe XIII] 10747~Å, and [Fe XIV]~5303~Å. We find that the FWHM of red line increases with height and that of green line decreases with height as observed earlier, at equatorial regions. The comparison of line widths and their gradients with the results from equatorial regions indicate that these are higher for polar regions for the observed emission lines except for the green line. FWHM values show an increase towards poles in all the lines except for the green line which shows little or no change. Higher values of FWHM at polar regions may imply higher non-thermal velocities which could be linked to the solar wind, but the behavior of green emission line with almost same values of FWHM at equatorial and polar regions is surprising. This may also give some indications on the existence of preferential heating.

Prasad Samayamanthula, Krishna; Banerjee, Dipankar; Singh, Jagdev

2012-07-01

206

Testing the Evolutionary Sequence between Hidden Broad-line Region (HBLR) and Non-HBLR Seyfert 2 Galaxies with the 4000 Å Break Strengths  

NASA Astrophysics Data System (ADS)

We compare the 4000 Å break (Dn (4000)) strength in the central kpc of hidden broad-line region (HBLR) and non-HBLR Seyfert 2 galaxies to investigate the origin of these galaxies. Our results show that the Dn (4000) strengths in the nuclear regions of the non-HBLR Seyfert 2 galaxies are larger than those in the HBLR galaxies. We also show that the Dn (4000) strength is not related to the morphology of host galaxies. These results imply that the non-HBLR Seyfert 2 galaxies have an older stellar population in nuclear regions than the HBLR galaxies. This suggests that an evolutionary connection might exist between non-HBLR and HBLR Seyfert 2 galaxies. We propose a potential evolutionary scenario and a modified unification model for Seyfert galaxies. In this scheme, Seyfert 1 and HBLR Seyfert 2 galaxies evolve into unabsorbed and absorbed non-HBLR Seyfert 2 galaxies. We also discuss the implications of our results in the hydrogen column density distribution of the non-HBLR Seyfert 2 galaxies.

Yu, Po-Chieh; Huang, Kui-Yun; Hwang, Chorng-Yuan; Ohyama, Youichi

2013-05-01

207

Design and performance of broadly tunable, narrow line-width, high repetition rate 1310nm VCSELs for swept source optical coherence tomography  

NASA Astrophysics Data System (ADS)

MEMS tunable vertical cavity surface emitting laser (MEMS-VCSEL) development, over the past two decades, has primarily focused on communications and spectroscopic applications. Because of the narrow line-width, single-mode operation, monolithic fabrication, and high-speed capability of these devices, MEMS-VCSELs also present an attractive optical source for emerging swept source optical coherence tomography (SSOCT) systems. In this paper, we describe the design and performance of broadly tunable MEMS-VCSELs targeted for SSOCT, emphasizing 1310nm operation for cancer and vascular imaging. We describe the VCSEL structure and fabrication, employing a fully oxidized GaAs/AlxOy mirrors in conjunction with dielectric mirrors and InP-based multi-quantum well active regions. We also describe the optimization of MEMs speed and frequency response for SSOCT. Key results include 1310 nm VCSELs with >120nm dynamic tuning range and imaging rates near 1MHz, representing the widest VCSEL tuning range and some of the fastest swept source imaging rates thus far obtained. We also describe how low-noise semiconductor optical amplification boosts average optical power to the required levels, while maintaining superior OCT imaging quality and state of the art system sensitivity. Finally, we present measured multi-centimeter dynamic coherence length, and discuss the implications of VCSELs for OCT.

Jayaraman, V.; Jiang, J.; Potsaid, B.; Cole, G.; Fujimoto, J.; Cable, A.

2012-02-01

208

The Main Virulence Determinant of Yersinia entomophaga MH96 Is a Broad-Host-Range Toxin Complex Active against Insects?†  

PubMed Central

Through transposon mutagenesis and DNA sequence analysis, the main disease determinant of the entomopathogenic bacterium Yersinia entomophaga MH96 was localized to an ?32-kb pathogenicity island (PAI) designated PAIYe96. Residing within PAIYe96 are seven open reading frames that encode an insecticidal toxin complex (TC), comprising not only the readily recognized toxin complex A (TCA), TCB, and TCC components but also two chitinase proteins that form a composite TC molecule. The central TC gene-associated region (?19 kb) of PAIYe96 was deleted from the Y. entomophaga MH96 genome, and a subsequent bioassay of the ?TC derivative toward Costelytra zealandica larvae showed it to be innocuous. Virulence of the ?TC mutant strain could be restored by the introduction of a clone containing the entire PAIYe96 TC gene region. As much as 0.5 mg of the TC is released per 100 ml of Luria-Bertani broth at 25°C, while at 30 or 37°C, no TC could be detected in the culture supernatant. Filter-sterilized culture supernatants derived from Y. entomophaga MH96, but not from the ?TC strain grown at temperatures of 25°C or less, were able to cause mortality. The 50% lethal doses (LD50s) of the TC toward diamondback moth Plutella xylostella and C. zealandica larvae were defined as 30 ng and 50 ng, respectively, at 5 days after ingestion. Histological analysis of the effect of the TC toward P. xylostella larva showed that within 48 h after ingestion of the TC, there was a general dissolution of the larval midgut.

Hurst, Mark R. H.; Jones, Sandra A.; Binglin, Tan; Harper, Lincoln A.; Jackson, Trevor A.; Glare, Travis R.

2011-01-01

209

On the Cosmic Evolution of the Scaling Relations Between Black Holes and Their Host Galaxies: Broad-Line Active Galactic Nuclei in the zCOSMOS Survey  

NASA Astrophysics Data System (ADS)

We report on the measurement of the physical properties (rest-frame K-band luminosity and total stellar mass) of the hosts of 89 broad-line (type-1) active galactic nuclei (AGNs) detected in the zCOSMOS survey in the redshift range 1 < z < 2.2. The unprecedented multi-wavelength coverage of the survey field allows us to disentangle the emission of the host galaxy from that of the nuclear black hole in their spectral energy distributions (SEDs). We derive an estimate of black hole masses through the analysis of the broad Mg II emission lines observed in the medium-resolution spectra taken with VIMOS/VLT as part of the zCOSMOS project. We found that, as compared to the local value, the average black hole to host-galaxy mass ratio appears to evolve positively with redshift, with a best-fit evolution of the form (1+z)^{0.68 ± 0.12 ^{+0.6}_{-0.3}}, where the large asymmetric systematic errors stem from the uncertainties in the choice of initial mass function, in the calibration of the virial relation used to estimate BH masses and in the mean QSO SED adopted. On the other hand, if we consider the observed rest-frame K-band luminosity, objects tend to be brighter, for a given black hole mass, than those on the local M BH-MK relation. This fact, together with more indirect evidence from the SED fitting itself, suggests that the AGN hosts are likely actively star-forming galaxies. A thorough analysis of observational biases induced by intrinsic scatter in the scaling relations reinforces the conclusion that an evolution of the M BH-M * relation must ensue for actively growing black holes at early times: either its overall normalization, or its intrinsic scatter (or both) appear to increase with redshift. This can be interpreted as signature of either a more rapid growth of supermassive black holes at high redshift, a change of structural properties of AGN hosts at earlier times, or a significant mismatch between the typical growth times of nuclear black holes and host galaxies. In any case, our results provide important clues on the nature of the early co-evolution of black holes and galaxies and challenging tests for models of AGN feedback and self-regulated growth of structures. Based on observations obtained at the European Southern Observatory (ESO) Very Large Telescope (VLT), Paranal, Chile, as part of the Large Program 175.A-0839 (the zCOSMOS Spectroscopic Redshift Survey). Also based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA Inc., under NASA contract NAS 5-26555; and on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; the XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA; the European Southern Observatory under Large Program 175.A-0839, Chile; the National Radio Astronomy Observatory which is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.; and the Canada-France-Hawaii Telescope with MegaPrime/MegaCam operated as a joint project by the CFHT Corporation, CEA/DAPNIA, the National Research Council of Canada, the Canadian Astronomy Data Centre, the Centre National de la Recherche Scientifique de France, TERAPIX, and the University of Hawaii.

Merloni, A.; Bongiorno, A.; Bolzonella, M.; Brusa, M.; Civano, F.; Comastri, A.; Elvis, M.; Fiore, F.; Gilli, R.; Hao, H.; Jahnke, K.; Koekemoer, A. M.; Lusso, E.; Mainieri, V.; Mignoli, M.; Miyaji, T.; Renzini, A.; Salvato, M.; Silverman, J.; Trump, J.; Vignali, C.; Zamorani, G.; Capak, P.; Lilly, S. J.; Sanders, D.; Taniguchi, Y.; Bardelli, S.; Carollo, C. M.; Caputi, K.; Contini, T.; Coppa, G.; Cucciati, O.; de la Torre, S.; de Ravel, L.; Franzetti, P.; Garilli, B.; Hasinger, G.; Impey, C.; Iovino, A.; Iwasawa, K.; Kampczyk, P.; Kneib, J.-P.; Knobel, C.; Kova?, K.; Lamareille, F.; Le Borgne, J.-F.; Le Brun, V.; Le Fèvre, O.; Maier, C.; Pello, R.; Peng, Y.; Perez Montero, E.; Ricciardelli, E.; Scodeggio, M.; Tanaka, M.; Tasca, L. A. M.; Tresse, L.; Vergani, D.; Zucca, E.

2010-01-01

210

Effective, Broad Spectrum Control of Virulent Bacterial Infections Using Cationic DNA Liposome Complexes Combined with Bacterial Antigens  

PubMed Central

Protection against virulent pathogens that cause acute, fatal disease is often hampered by development of microbial resistance to traditional chemotherapeutics. Further, most successful pathogens possess an array of immune evasion strategies to avoid detection and elimination by the host. Development of novel, immunomodulatory prophylaxes that target the host immune system, rather than the invading microbe, could serve as effective alternatives to traditional chemotherapies. Here we describe the development and mechanism of a novel pan-anti-bacterial prophylaxis. Using cationic liposome non-coding DNA complexes (CLDC) mixed with crude F. tularensis membrane protein fractions (MPF), we demonstrate control of virulent F. tularensis infection in vitro and in vivo. CLDC+MPF inhibited bacterial replication in primary human and murine macrophages in vitro. Control of infection in macrophages was mediated by both reactive nitrogen species (RNS) and reactive oxygen species (ROS) in mouse cells, and ROS in human cells. Importantly, mice treated with CLDC+MPF 3 days prior to challenge survived lethal intranasal infection with virulent F. tularensis. Similarly to in vitro observations, in vivo protection was dependent on the presence of RNS and ROS. Lastly, CLDC+MPF was also effective at controlling infections with Yersinia pestis, Burkholderia pseudomallei and Brucella abortus. Thus, CLDC+MPF represents a novel prophylaxis to protect against multiple, highly virulent pathogens.

Ireland, Robin; Olivares-Zavaleta, Norma; Warawa, Jonathan M.; Gherardini, Frank C.; Jarrett, Clayton; Hinnebusch, B. Joseph; Belisle, John T.; Fairman, Jeffery; Bosio, Catharine M.

2010-01-01

211

BROAD-LINE RADIO GALAXIES OBSERVED WITH FERMI-LAT: THE ORIGIN OF THE GeV {gamma}-RAY EMISSION  

SciTech Connect

We report on a detailed investigation of the {gamma}-ray emission from 18 broad-line radio galaxies (BLRGs) based on two years of Fermi Large Area Telescope data. We confirm the previously reported detections of 3C 120 and 3C 111 in the GeV photon energy range; a detailed look at the temporal characteristics of the observed {gamma}-ray emission reveals in addition possible flux variability in both sources. No statistically significant {gamma}-ray detection of the other BLRGs was found, however, in the considered data set. Though the sample size studied is small, what appears to differentiate 3C 111 and 3C 120 from the BLRGs not yet detected in {gamma}-rays is the particularly strong nuclear radio flux. This finding, together with the indications of the {gamma}-ray flux variability and a number of other arguments presented, indicates that the GeV emission of BLRGs is most likely dominated by the beamed radiation of relativistic jets observed at intermediate viewing angles. In this paper we also analyzed a comparison sample of high-accretion-rate Seyfert 1 galaxies, which can be considered radio-quiet counterparts of BLRGs, and found that none were detected in {gamma}-rays. A simple phenomenological hybrid model applied for the broadband emission of the discussed radio-loud and radio-quiet type 1 active galaxies suggests that the relative contribution of the nuclear jets to the accreting matter is {>=}1% on average for BLRGs, whereas it is {<=}0.1% for Seyfert 1 galaxies.

Kataoka, J.; Takahashi, Y.; Maeda, K.; Nakamori, T. [Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Stawarz, L. [Institute of Space and Astronautical Science, JAXA, Kanagawa 252-5210 (Japan); Cheung, C. C. [National Academy of Sciences, Washington, DC 20001 (United States); Hayashida, M.; Digel, S. W. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Grandi, P. [INAF-IASF Bologna, 40129 Bologna (Italy); Burnett, T. H. [Department of Physics, University of Washington, Seattle, WA 98195-1560 (United States); Celotti, A. [Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34014 Trieste (Italy); Fegan, S. J.; Fortin, P. [Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS/IN2P3, Palaiseau (France); Taylor, G. B. [Department of Physics and Astronomy, University of New Mexico, MSC07 4220, Albuquerque, NM 87131 (United States); Tosti, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); McConville, W. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Finke, J. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); D'Ammando, F., E-mail: kataoka.jun@waseda.jp [IASF Palermo, 90146 Palermo (Italy)

2011-10-10

212

Weak Hard X-Ray Emission from Two Broad Absorption Line Quasars Observed with NuSTAR: Compton-thick Absorption or Intrinsic X-Ray Weakness?  

NASA Astrophysics Data System (ADS)

We present Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray weak, probably due to absorption by the shielding gas between the nucleus and the accretion-disk wind. The two targets are among the optically brightest BAL quasars, yet they are known to be significantly X-ray weak at rest-frame 2-10 keV (16-120 times fainter than typical quasars). We would expect to obtain ?400-600 hard X-ray (gsim 10 keV) photons with NuSTAR, provided that these photons are not significantly absorbed (N H <~ 1024 cm-2). However, both BAL quasars are only detected in the softer NuSTAR bands (e.g., 4-20 keV) but not in its harder bands (e.g., 20-30 keV), suggesting that either the shielding gas is highly Compton-thick or the two targets are intrinsically X-ray weak. We constrain the column densities for both to be N H ? 7 × 1024 cm-2 if the weak hard X-ray emission is caused by obscuration from the shielding gas. We discuss a few possibilities for how PG 1004+130 could have Compton-thick shielding gas without strong Fe K? line emission; dilution from jet-linked X-ray emission is one likely explanation. We also discuss the intrinsic X-ray weakness scenario based on a coronal-quenching model relevant to the shielding gas and disk wind of BAL quasars. Motivated by our NuSTAR results, we perform a Chandra stacking analysis with the Large Bright Quasar Survey BAL quasar sample and place statistical constraints upon the fraction of intrinsically X-ray weak BAL quasars; this fraction is likely 17%-40%.

Luo, B.; Brandt, W. N.; Alexander, D. M.; Harrison, F. A.; Stern, D.; Bauer, F. E.; Boggs, S. E.; Christensen, F. E.; Comastri, A.; Craig, W. W.; Fabian, A. C.; Farrah, D.; Fiore, F.; Fuerst, F.; Grefenstette, B. W.; Hailey, C. J.; Hickox, R.; Madsen, K. K.; Matt, G.; Ogle, P.; Risaliti, G.; Saez, C.; Teng, S. H.; Walton, D. J.; Zhang, W. W.

2013-08-01

213

Distribution Line Protection Relaying Scheme Based on Complex Number Operation  

NASA Astrophysics Data System (ADS)

In Japan, operational principles from the mechanical-type era, such as the directional ground relay (DG) and overcurrent relay (OC), are still used without modification for the protection of distribution lines. We are now facing various problems, such as ground faults with high fault resistance in systems isolated from the ground. A new operational principle to solve the above problems is summarized below. ·A fault is simulated by replacing a branched distribution line with a one-section single distribution line, in which loads are concentrated at its terminals. ·Lines with a one-line to ground fault are detected on the basis of the relationship between the fault-phase voltage E before the fault and the fault current using Ho and Thevenin's theorem. ·Faults are assumed to occur at both terminals in the section. If the signs of the obtained fault reactance Xf at the two terminals are opposite, it is judged that a fault point where Xf = 0 holds exists within the section. As a result of the simulation using the program we developed, it was confirmed that no errors in the detection of the internal and external ground faults with a high fault resistance of 0-30k? were observed.

Tsuji, Kouichi

214

Iron Line Complex from Illuminated Accretion Disk Atmospheres  

NASA Astrophysics Data System (ADS)

We present full set of model atmosphere equations corresponding to an accretion disk around a supermassive black hole illuminated by hard X-ray power-law. Model equations allow for multiple Compton scattering of radiation on free electrons, and for large relative photon-electron energy exchange. We present spectra in specific intensities integrated over disk surface. Outgoing intensity spectra show soft X-ray excess below 1 keV, and distinct K? and K? fluorescent lines of iron. We demonstrate the existence of the Compton shoulder and claim that it can contribute to the asymmetry and equivalent widths of some observed lines in AGN.

Ró?a?ska, A.; Madej, J.

2009-05-01

215

Distribution Line Protection Relaying Scheme Based on Complex Number Operation  

Microsoft Academic Search

In Japan, operational principles from the mechanical-type era, such as the directional ground relay (DG) and overcurrent relay (OC), are still used without modification for the protection of distribution lines. We are now facing various problems, such as ground faults with high fault resistance in systems isolated from the ground. A new operational principle to solve the above problems is

Kouichi Tsuji

2009-01-01

216

Flow Dynamics Along Complex Magnetically Insulated Transmission Lines  

Microsoft Academic Search

We study by PIC simulations the simple model of a magnetically insulated transmission line fed by a matched voltage source and driven additionally by a single transverse source adding voltage to it at a certain point along its length. For best power flow, an impedance transition is required after this point. We study the effect of the parameters of this

John G. Leopold; Raanan Gad; Itamar Navon

2012-01-01

217

Complex field recovering from in-line digital holography.  

PubMed

This Letter presents an in-line digital holographic system that can provide full amplitude and phase reconstruction without any reference wave, with a single recorded hologram. This major capability is obtained by using a coherent mixing between several object waves generated by a pure spatial phase modulation. A scaling parameter permits us to reconstruct the phase without any unwrapping. The capability of the method to provide quantitative phase contrast measurement and numerical refocusing is demonstrated through experimental results. PMID:23988921

Picart, Pascal; Malek, Mokrane

2013-09-01

218

On-line complex permittivity measurements for ground penetrating radar  

Microsoft Academic Search

One of the major problems for a subsurface radar to predict is the true target distance and maximum likely penetration depth in the media under investigation. These radar parameters can be determined from the complex permittivity of the media. Since the permittivity of the surface under examination is usually unknown, most subsurface radars are calibrated in time units only: actual

N. Ballard; Alan Langman; Michael R. Inggs

1994-01-01

219

CONSTRAINTS ON BLACK HOLE GROWTH, QUASAR LIFETIMES, AND EDDINGTON RATIO DISTRIBUTIONS FROM THE SDSS BROAD-LINE QUASAR BLACK HOLE MASS FUNCTION  

SciTech Connect

We present an estimate of the black hole mass function of broad-line quasars (BLQSOs) that self-consistently corrects for incompleteness and the statistical uncertainty in the mass estimates, based on a sample of 9886 quasars at 1 < z < 4.5 drawn from the Sloan Digital Sky Survey (SDSS). We find evidence for 'cosmic downsizing' of black holes in BLQSOs, where the peak in their number density shifts to higher redshift with increasing black hole mass. The cosmic mass density for black holes seen as BLQSOs peaks at z {approx} 2. We estimate the completeness of the SDSS as a function of the black hole mass and Eddington ratio, and find that at z > 1 it is highly incomplete at M {sub BH} {approx}< 10{sup 9} M {sub sun} and L/L{sub Edd} {approx}< 0.5. We estimate a lower limit on the lifetime of a single BLQSO phase to be t {sub BL} > 150 {+-} 15 Myr for black holes at z = 1 with a mass of M {sub BH} = 10{sup 9} M{sub sun}, and we constrain the maximum mass of a black hole in a BLQSO to be {approx}3 x 10{sup 10} M{sub sun}. Our estimated distribution of BLQSO Eddington ratios peaks at L/L {sub Edd} {approx} 0.05 and has a dispersion of {approx}0.4 dex, implying that most BLQSOs are not radiating at or near the Eddington limit; however, the location of the peak is subject to considerable uncertainty. The steep increase in number density of BLQSOs toward lower Eddington ratios is expected if the BLQSO accretion rate monotonically decays with time. Furthermore, our estimated lifetime and Eddington ratio distributions imply that the majority of the most massive black holes spend a significant amount of time growing in an earlier obscured phase, a conclusion which is independent of the unknown obscured fraction. These results are consistent with models for self-regulated black hole growth, at least for massive systems at z > 1, where the BLQSO phase occurs at the end of a fueling event when black hole feedback unbinds the accreting gas, halting the accretion flow.

Kelly, Brandon C.; Hernquist, Lars; Siemiginowska, Aneta [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Vestergaard, Marianne; Fan Xiaohui [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Hopkins, Philip, E-mail: bckelly@cfa.harvard.ed [Department of Astronomy, University of California, Berkeley, CA (United States)

2010-08-20

220

Large-scale, lineage-specific expansion of a bric-a-brac/tramtrack/broad complex ubiquitin-ligase gene family in rice.  

PubMed

Selective ubiquitination of proteins is directed by diverse families of ubiquitin-protein ligases (or E3s) in plants. One important type uses Cullin-3 as a scaffold to assemble multisubunit E3 complexes containing one of a multitude of bric-a-brac/tramtrack/broad complex (BTB) proteins that function as substrate recognition factors. We previously described the 80-member BTB gene superfamily in Arabidopsis thaliana. Here, we describe the complete BTB superfamily in rice (Oryza sativa spp japonica cv Nipponbare) that contains 149 BTB domain-encoding genes and 43 putative pseudogenes. Amino acid sequence comparisons of the rice and Arabidopsis superfamilies revealed a near equal repertoire of putative substrate recognition module types. However, phylogenetic comparisons detected numerous gene duplication and/or loss events since the rice and Arabidopsis BTB lineages split, suggesting possible functional specialization within individual BTB families. In particular, a major expansion and diversification of a subset of BTB proteins containing Meprin and TRAF homology (MATH) substrate recognition sites was evident in rice and other monocots that likely occurred following the monocot/dicot split. The MATH domain of a subset appears to have evolved significantly faster than those in a smaller core subset that predates flowering plants, suggesting that the substrate recognition module in many monocot MATH-BTB E3s are diversifying to ubiquitinate a set of substrates that are themselves rapidly changing. Intriguing possibilities include pathogen proteins attempting to avoid inactivation by the monocot host. PMID:17720868

Gingerich, Derek J; Hanada, Kousuke; Shiu, Shin-Han; Vierstra, Richard D

2007-08-24

221

Holocene planform change in broad valleys in the Southern Rocky Mountains: the role of vegetation type and beaver in shaping long-term channel complexity  

NASA Astrophysics Data System (ADS)

Over the past decade, researchers have shown the importance of streambank vegetation in forming meandering channels. Recent work has also showed the importance of beaver in creating a more heterogeneous landscape, in terms of channel planform and complexity, sedimentation, and riparian vegetation. Streambank vegetation and beavers interact as ecosystem engineers to determine long-term channel planform, floodplain processes, and complexity. We use studies of Holocene beaver aggradation and effects on channel complexity, in addition to measurements of added bank strength by various riparian vegetation types, to predict Holocene planform change in broad (>200 m, disconnected from hillslopes), high-elevation (>2300 m) valleys of the Colorado Front Range in the Southern Rocky Mountains. Sediment core analyses and shallow subsurface geophysical measurements indicate that post-glacial beaver-related aggradation is significant. Additionally, historical and field evidence from the last century, when the beaver population steadily declined, shows that beaver contribute to the formation of a complex, multi-thread channel network. Streambank vegetation in the Colorado Front Range can be categorized based on its ability to provide added strength to the streambank, where riparian or rhizomatous shrubs and trees provide more strength than xeric trees or non-rhizomatous graminoids and herbs, depending on the bank texture and hydrologic conditions. Assuming a snowmelt-dominated flow regime in a gravel-bed channel system, four planform regimes are identified based on beaver populations and the abundance and presence of xeric or riparian vegetation. Following deglaciation, without beaver or bank-stabilizing vegetation, (1) a braided channel formed. The introduction of riparian vegetation and a more stable flow regime triggered a transition to (2) a meandering channel, which in turn provided habitat for beaver, allowing the formation of (3) a complex multi-thread channel system. The fourth planform regime occurs only after beaver that occupied a valley for a long period have been removed. With a stable beaver population, ponds trap large amounts of fine, cohesive sediment, which becomes incorporated into the floodplain sediment and streambanks after channel migration. A legacy effect from beaver removal, which is accompanied by higher gradient and thus stream power, and a lowered water table and thus more xeric vegetation, is (4) a narrow, incised channel. These planform regimes can be inferred over the range of Holocene climate conditions in the Colorado Front Range, and understanding of these biotic-physical interactions should be a crucial component of any management decisions for geomorphic or ecologic conditions.

Polvi-Pilgrim, L. E.; Wohl, E.

2012-04-01

222

Fermionic screenings and line bundle twisted chiral de Rham complex on CY manifolds  

NASA Astrophysics Data System (ADS)

We present a generalization of Borisov's construction of the chiral de Rham complex in the case of the line-bundle-twisted chiral de Rham complex on a Calabi-Yau hypersurface in a projective space. We generalize the differential associated with a polytope ? of the projective space ? d - 1 by allowing nonzero modes for the screening currents forming this differential. It is shown that the numbers of screening current modes define the support function of the toric divisor of a line bundle on ? d - 1 that twists the chiral de Rham complex on the Calabi-Yau hypersurface.

Parkhomenko, S. E.

2012-01-01

223

The Ecdysone-Inducible Broad-Complex and E74 Early Genes Interact to Regulate Target Gene Transcription and Drosophila Metamorphosis  

PubMed Central

Pulses of the steroid hormone ecdysone initiate Drosophila metamorphosis by inducing widespread changes in gene expression. The Broad-Complex (BR-C) and E74 are induced directly by ecdysone and encode families of transcription factors that regulate ecdysone primary- and secondary-response genes. Genetic analyses have revealed that mutations in the BR-C and E74 are lethal during metamorphosis and that these mutations cause some similar lethal phenotypes and alterations in secondary-response gene transcription. To examine whether the BR-C and E74 function together during development, we have combined representative alleles from each BR-C and E74 complementation group. Analysis of the morphological and molecular phenotypes of the double-mutant animals reveals that BR-C and E74 alleles act together to produce both novel and synergistic effects. We find that the BR-C and E74 share functions in puparium formation, pupation and early gene induction. In addition, our evidence suggests that the BR-C and E74 transcription factors may directly interact to regulate the expression of salivary gland glue and late genes. This data is consistent with current models which propose that combinations of ecdysone primary-response genes regulate common morphogenetic pathways during insect metamorphosis.

Fletcher, J. C.; Thummel, C. S.

1995-01-01

224

Steps toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XI. Intensive Monitoring of the Ultraviolet Spectrum of NGC 7469  

Microsoft Academic Search

From 1996 June 10 to July 29, the International Ultraviolet Explorer monitored the Seyfert 1 galaxy NGC 7469 continuously in an attempt to measure time delays between the continuum and emission-line fluxes. From the time delays, one can estimate the size of the region dominating the production of the UV emission lines in this source. We find the strong UV

I. Wanders; B. M. Peterson; D. Alloin; T. R. Ayres; J. Clavel; D. M. Crenshaw; K. Horne; G. A. Kriss; J. H. Krolik; M. A. Malkan; H. Netzer; P. T. O'Brien; G. A. Reichert; P. M. Rodriguez-Pascual; W. Wamsteker; T. Alexander; K. S. J. Anderson; E. Benitez; N. G. Bochkarev; A. N. Burenkov; F.-Z. Cheng; S. J. Collier; A. Comastri; M. Dietrich; D. Dultzin-Hacyan; B. R. Espey; A. V. Filippenko; C. M. Gaskell; I. M. George; M. R. Goad; L. C. Ho; S. Kaspi; W. Kollatschny; K. T. Korista; A. Laor; G. M. MacAlpine; M. Mignoli; S. L. Morris; K. Nandra; S. Penton; R. W. Pogge; R. L. Ptak; J. M. Rodriguez-Espinoza; M. Santos-Lleo; A. I. Shapovalova; J. M. Shull; S. A. Snedden; L. S. Sparke; G. M. Stirpe; W.-H. Sun; T. J. Turner; M.-H. Ulrich; T.-G. Wang; C. Wei; W. F. Welsh; S.-J. Xue; Z.-L. Zou

1997-01-01

225

Separation and Identification of HSP-Associated Protein Complexes from Pancreatic Cancer Cell Lines Using 2D CN/SDS-PAGE Coupled with Mass Spectrometry  

PubMed Central

Protein complexes are a cornerstone of many biological processes and together they form various types of molecular machinery. A broad understanding of these protein complexes is crucial for revealing and building models of protein function and regulation. Pancreatic cancer is a highly lethal disease which is difficult to diagnose at early stage and even more difficult to cure. In this study, we applied a gradient clear native gel system combined with subsequent second-dimensional SDS-PAGE to separate protein complexes from cell lysates of SW1990 and PANC-1 pancreatic cancer cell lines with different degrees of differentiation. Ten heat-shock-protein- (HSP-) associated protein complexes were separated and identified, and the differentially expressed proteins related to cancers were also found, such as HSP60, protein disulfide-isomerase A4 (ERp72), and transitional endoplasmic reticulum ATPase (TER ATPase).

Zhao, Zhiyun; Liu, Hui; Wang, Xinli; Wang, Xiaodong; Li, Zhili

2011-01-01

226

COMPTEL observations of the Orion complex: Evidence for cosmic-ray induced gamma-ray lines  

Microsoft Academic Search

We report the detection of gamma-ray emission from the Orion complex in the 3-7 MeV range by the Imaging Compton Telescope (COMPTEL) telescope aboard the Compton Gamma Ray Observatory (CGRO). This emission can be identified with the 4.44 MeV and 6.13 MeV nuclear de-excitation lines of C-12star and O-16star, respectively, which are predicted to be the strongest gamma-ray lines originating

H. Bloemen; R. Wijnands; K. Bennett; R. Diehl; W. Hermsen; G. Lichti; D. Morris; J. Ryan; V. Schonfelder; A. W. Strong; B. N. Swanenburg; C. de Vries; C. Winkler

1994-01-01

227

Expression and clinical role of the bric-a-brac tramtrack broad complex/poxvirus and zinc protein NAC-1 in ovarian carcinoma effusions.  

PubMed

We recently identified NAC-1, member of the bric-a-brac tramtrack broad complex/poxvirus and zinc domain family, as an overexpressed gene in ovarian serous carcinoma and found more frequent NAC-1 protein expression in recurrent compared to primary tumors. In the present study, we assessed the clinical significance of NAC-1 expression in ovarian carcinoma effusions. Formalin-fixed, paraffin-embedded sections from 176 effusions (137 peritoneal, 39 pleural) and 197 corresponding solid tumors (69 primary tumors, 128 solid metastases) were analyzed for NAC-1 expression using immunohistochemistry. Staining intensity and extent results were analyzed for possible association with clinicopathologic parameters and survival. Nuclear NAC-1 immunoreactivity was found in carcinoma cells in 98% of (173/176) effusions, 94% (65/69) of primary tumors, and 95% (121/128) of metastases. Staining intensity and extent were significantly higher in effusions compared with matched solid tumors (P = .002 for intensity, P = .003 for extent compared with primary tumors; P < .001 for both intensity and extent compared with metastases). Furthermore, NAC-1 expression intensity was significantly higher in specimens obtained after the administration of chemotherapy (P = .002) and correlated with shorter progression-free survival (PFS) in analysis of 62 patients with post-chemotherapy effusions (P = .039). International Federation of Gynecology and Obstetrics stage (IV versus III) was the only clinical parameter associated with PFS in this group (P = .004). In Cox analysis, only the International Federation of Gynecology and Obstetrics stage was an independent predictor of shorter PFS (P = .009). In conclusion, NAC-1 expression is higher in ovarian carcinoma cells in effusions compared with their solid tumor counterparts. NAC-1 is up-regulated in tumor cells after chemotherapy, suggesting a role for this protein in tumor progression and in the development of chemotherapy resistance in ovarian cancer. PMID:17391728

Davidson, Ben; Berner, Aasmund; Trope', Claes G; Wang, Tian-Li; Shih, Ie-Ming

2007-03-27

228

Zip14 is a complex broad-scope metal-ion transporter whose functional properties support roles in the cellular uptake of zinc and nontransferrin-bound iron.  

PubMed

Recent studies have shown that overexpression of the transmembrane protein Zrt- and Irt-like protein 14 (Zip14) stimulates the cellular uptake of zinc and nontransferrin-bound iron (NTBI). Here, we directly tested the hypothesis that Zip14 transports free zinc, iron, and other metal ions by using the Xenopus laevis oocyte heterologous expression system, and use of this approach also allowed us to characterize the functional properties of Zip14. Expression of mouse Zip14 in RNA-injected oocytes stimulated the uptake of (55)Fe in the presence of l-ascorbate but not nitrilotriacetic acid, indicating that Zip14 is an iron transporter specific for ferrous ion (Fe(2+)) over ferric ion (Fe(3+)). Zip14-mediated (55)Fe(2+) uptake was saturable (K(0.5) ? 2 ?M), temperature-dependent (apparent activation energy, E(a) = 15 kcal/mol), pH-sensitive, Ca(2+)-dependent, and inhibited by Co(2+), Mn(2+), and Zn(2+). HCO(3)(-) stimulated (55)Fe(2+) transport. These properties are in close agreement with those of NTBI uptake in the perfused rat liver and in isolated hepatocytes reported in the literature. Zip14 also mediated the uptake of (109)Cd(2+), (54)Mn(2+), and (65)Zn(2+) but not (64)Cu (I or II). (65)Zn(2+) uptake also was saturable (K(0.5) ? 2 ?M) but, notably, the metal-ion inhibition profile and Ca(2+) dependence of Zn(2+) transport differed from those of Fe(2+) transport, and we propose a model to account for these observations. Our data reveal that Zip14 is a complex, broad-scope metal-ion transporter. Whereas zinc appears to be a preferred substrate under normal conditions, we found that Zip14 is capable of mediating cellular uptake of NTBI characteristic of iron-overload conditions. PMID:21653899

Pinilla-Tenas, Jorge J; Sparkman, Brian K; Shawki, Ali; Illing, Anthony C; Mitchell, Colin J; Zhao, Ningning; Liuzzi, Juan P; Cousins, Robert J; Knutson, Mitchell D; Mackenzie, Bryan

2011-06-08

229

Faint early-type stars and emission-line stars in the Canis Majoris complex.  

NASA Astrophysics Data System (ADS)

In order to study the distribution of OB stars in the Canis Majoris complex, a survey and classification have been done for stars in the area. The study is based on spectral observations at the Kiso Schmidt tlescope. In the present field about 1800 OBA stars were classified, where the majority is dominated by B late and A early type stars. A survey for emission-line stars was also carried out in the same region. In total, 128 emission-line stars were detected, ranging from V = 6 to 15. A comparison shows that some emission-line stars of this region contained in the existing catalogs are common with the authors', and some exhibit no detectable emission line on the plates. This can probably be considered as the result of variation in emission-line strength.

Wiramihardja, S. D.; Kogure, T.

230

Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. III - Further observations of NGC 5548 at optical wavelengths  

Microsoft Academic Search

The results of the second year of an intensive ground-based spectroscopic and photometric study of variability in the bright Seyfert 1 galaxy NGC 5548 are reported in order to study the relationship between continuum and emission-line variability. Relative to the first year of the monitoring program, the nucleus of NGC 5548 was considerably fainter and the continuum variations slower during

B. M. Peterson; D. Alloin; D. Axon; T. J. Balonek; R. Bertram; T. A. Boroson; J. A. Christensen; S. D. Clements; M. Dietrich; M. Elvis; A. V. Filippenko; C. M. Gaskell; C. A. Haswell; J. P. Huchra; N. Jackson; W. Kollatschny; K. T. Korista; N. J. Lame; R. J. Leacock; S.-N. Lin; M. A. Malkan; A. S. Monk; M. V. Penston; R. W. Pogge; A. Robinson; E. I. Rosenblatt; J. C. Shields; A. G. Smith; G. M. Stirpe; W.-H. Sun; T. J. Turner; R. M. Wagner; B. J. Wilkes; B. J. Wills

1992-01-01

231

Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. II - an intensive study of NGC 5548 at optical wavelengths  

Microsoft Academic Search

A large, international program of ground-based optical spectroscopy and photometry of the variable Seyfert 1 galaxy NGC 5548 undertaken in support of an IUE monitoring campaign is described. This contribution presents the data base and describes the methods used to correct for systematic differences between spectra from different sources. Optical continuum and H-beta emission-line light curves are derived from the

B. M. Peterson; T. J. Balonek; E. S. Barker; J. Bechtold; R. Bertram; N. G. Bochkarev; M. J. Bolte; D. Bond; T. A. Boroson; M. T. Carini; T. E. Carone; J. A. Christensen; S. D. Clements; A. L. Cochran; R. D. Cohen; D. Crampton; M. Dietrich; M. Elvis; A. Ferguson; A. V. Filippenko; K. J. Fricke; C. M. Gaskell; J. P. Halpern; J. P. Huchra; J. B. Hutchings; W. Kollatschny; A. P. Koratkar; K. T. Korista; J. H. Krolik; N. J. Lame; A. Laor; R. J. Leacock; G. M. MacAlpine; M. A. Malkan; D. Maoz; H. R. Miller; S. L. Morris; H. Netzer; C. L. M. Oliveira; J. Penfold; M. V. Penston; E. Perez; R. W. Pogge; M. W. Richmond; W. Romanishin; E. I. Rosenblatt; L. Saddlemyer; A. Sadun; S. R. Sawyer; J. C. Shields; A. I. Shapovalova; A. G. Smith; H. A. Smith; P. S. Smith; W.-H. Sun; U. Thiele; T. J. Turner; S. Veilleux; R. M. Wagner; R. J. Weymann; B. J. Wilkes; B. J. Wills; D. Wills; P. F. Younger

1991-01-01

232

Identification of Triploid Individuals and Clonal Lines in Carassius Auratus Complex Using Microsatellites  

PubMed Central

The Carassius auratus complex in natural populations includes diploid triploid and polyploidy individuals. Diploid individuals belong to the species Carassius auratus whereas triploid and polyploidy individuals are from the subspecies Carassius auratus gibelio. Triploid individuals are all female and reproduce clonally by gynogenesis. Therefore the Carassius auratus complex is an ideal system for studying evolution of unisexual reproduction. Identification of triploid individuals and clonal lines is the first step towards understanding of the evolution of unisexual clonal lines. We examined the ability of 10 microsatellites in identifying triploid individuals in 94 individuals from Japan and China. In 40 confirmed triploid individuals and eight confirmed diploid individuals, all triploid and diploid individuals can be identified by genotyping 10 microsatellite, and four triploid clonal lines were identified. Using the 10 microsatellites we genotyped 46 adult individuals (40 females and six males) from a natural population in China and found that all six males were diploid whereas the majority of females (36 of 40) were triploid and three triploid clonal lines were detected. In 18 diploid individuals from China, all individuals showed different genotypes, suggesting there is no diploid clonal line in diploid crucian carp. A phylogenetic analysis of 94 individuals from China and Japan showed that triploid individuals and clonal lines have originated recurrently.

Bai, Zhiyi; Liu, Feng; Li, Jiale; Yue, Gen Hua

2011-01-01

233

Identification and expression analysis of the Broad-Complex core protein isoform 6 (BR-C Z6) gene in the giant tiger shrimp Penaeus monodon (Penaeidae: Decapoda).  

PubMed

Broad-Complex (BR-C) is an early ecdysone-responsive gene encoding a family of zinc-finger transcription factors that function during metamorphosis in insects. We identified two full-length cDNAs of BR-C Z6 in the giant tiger shrimp (Penaeus monodon). They were 2422 and 2060 bp in length, containing open reading frames of 1440 and 1443 bp, corresponding to polypeptides of 479 and 480 amino acids, respectively. Tissue distribution analysis indicated that PmBR-C Z6 was abundantly expressed in hemocytes and ovaries in juveniles. In broodstock, PmBR-C Z6 was constitutively expressed in all tissues examined, and the highest expression was observed in ovaries. The expression of PmBR-C Z6 in ovaries was significantly greater than in testes in both juveniles and broodstock of P. monodon. Quantitative real-time PCR indicated that the expression level of PmBR-C Z6 was significantly down-regulated in stages II and III of ovaries in intact wild broodstock and returned to the basal level in stage IV ovaries and after spawning. In eyestalk-ablated broodstock, PmBR-C Z6 was significantly up-regulated in stage IV (mature) ovaries. Moreover, the expression level of PmBR-C Z6 in vitellogenic, early cortical rod and mature (stages II-IV) ovaries of eyestalk-ablated broodstock was greater than that of the same ovarian stages in intact broodstock. In situ hybridization revealed that PmBR-C Z6 transcripts were localized in oogonia and cytoplasm of previtellogenic and vitellogenic oocytes of both wild intact and eyestalk-abated broodstock. The effects of 20-hydroxyecdysone on expression of PmBR-C Z6 were examined. The expression level of PmBR-C Z6 in ovaries of juvenile P. monodon was significantly increased at 168 h post-injection. Taken together, these findings indicate that PmBR-C Z6 plays an important role in ovarian development of P. monodon. PMID:22002123

Buaklin, A; Klinbunga, S; Mensveta, P

2011-10-03

234

Determining complex permittivity from propagation constant measurements with planar transmission lines  

NASA Astrophysics Data System (ADS)

A new two-standard calibration procedure is outlined for determining the complex permittivity of materials from the propagation constant measured with planar transmission lines. Once calibrated, a closed-form expression for the material permittivity is obtained. The effects of radiation and conductor losses are accounted for in the calibration. The multiline technique, combined with a recently proposed planar transmission-line configuration, is used to determine the line propagation constant. An uncertainty analysis is presented for the proposed calibration procedure that includes the uncertainties associated with the multiline technique. This allows line dimensions and calibration standards to be selected that minimize the total measurement uncertainty. The use of air and distilled water as calibration standards gives relatively small measurement uncertainty. Permittivity measurement results for five liquids, covering a wide permittivity range, agree very closely with expected values from 0.5-5 GHz.

Roelvink, J.; Trabelsi, S.; Nelson, S. O.

2013-10-01

235

Characterization of the E-cadherin/catenin complex in colorectal carcinoma cell lines  

PubMed Central

The E-cadherin/catenin complex is a prime mediator of cell–cell adhesion. APC mutations can result in loss of ?-catenin downregulation and an accumulation of ?-catenin in the cell. ?-CATENIN mutations can have a similar effect. The aim of this study was to investigate the effect of ?-CATENIN and APC mutations on the expression and assembly of the E-cadherin/catenin complex. Five colorectal carcinoma cell lines with different APC and ?-CATENIN gene status were selected and mutations were confirmed. The expression of members of the E-cadherin/catenin complex was studied by immunohistochemistry and Western blotting. Complex assembly was investigated by immunoprecipitation. It is shown that E-cadherin and catenins are expressed in colorectal carcinoma cell lines with the predominant complex assembly being E-cadherin/?-catenin/?-catenin. The subcellular distribution of the proteins is influenced by cell–cell contact, resulting in membranous localization. The expression and assembly of the E-cadherin/catenin complex does not appear to be affected by the presence of APC and or ?-CATENIN mutations.

El-Bahrawy, Mona; Poulsom, S Richard; Rowan, Andrew J; Tomlinson, Ian T; Alison, Malcolm R

2004-01-01

236

The broad iron K? line of Cygnus X-1 as seen by XMM-Newton in the EPIC-pn modified timing mode  

NASA Astrophysics Data System (ADS)

We present the analysis of the broadened, flourescent iron K? line in simultaneous XMM-Newton and RXTE data from the black hole Cygnus X-1. The XMM-Newton data were taken in a modified version of the timing mode of the EPIC-pn camera. In this mode the lower energy threshold of the instrument is increased to 2.8 keV to avoid telemetry drop outs due to the brightness of the source, while at the same time preserving the signal-to-noise ratio in the Fe K? band. We find that the best-fit spectrum consists of the sum of an exponentially cutoff power-law and relativistically smeared, ionized reflection. The shape of the broadened Fe K? feature is due to strong Compton broadening combined with relativistic broadening. Assuming a standard, thin accretion disk, the black hole is close to rotating maximally.

Duro, R.; Dauser, T.; Wilms, J.; Pottschmidt, K.; Nowak, M. A.; Fritz, S.; Kendziorra, E.; Kirsch, M. G. F.; Reynolds, C. S.; Staubert, R.

2011-09-01

237

Nonseptic diseases associated with the hoof complex: keratoma, white line disease, canker, and neoplasia.  

PubMed

This article addresses nonseptic diseases associated with the hoof complex, namely keratoma, white line disease, canker, and neoplasia. Keratoma is an uncommon cause of lameness, which may be surgically removed. White line disease, a keratolytic process on the solar surface of the hoof, is treated with therapeutic farriery and resection of the hoof wall when appropriate. Equine canker is an infectious process that results in development of a chronic hypertrophy of the horn-producing tissues. Neoplasia involving the equine foot is rare, and melanoma is the most common type of neoplasm reported. PMID:22981198

Redding, W Rich; O'Grady, Stephen E

2012-08-01

238

Fe K LINE COMPLEX IN THE NUCLEAR REGION OF NGC 253  

SciTech Connect

A bright, nearby edge-on starburst galaxy, NGC 253, was studied using the Suzaku, XMM, and Chandra X-ray observatories. With Suzaku and XMM we detected complex line structure of Fe K, which is resolved into three lines (Fe I at 6.4 keV, Fe XXV at 6.7 keV, and Fe XXVI at 7.0 keV) around the center of NGC 253. Especially, the Fe I and Fe XXVI lines are the first clear detections, with a significance of >99.99% and 99.89% estimated by a Monte Carlo procedure. Imaging spectroscopy with Chandra revealed that the emission is distributed in {approx}60 arcsec{sup 2} region around the nucleus, which suggests that the source is not only the buried active galactic nucleus. The flux of highly ionized Fe lines can be explained by the accumulation of 10-1000 supernova remnants that are the result of high star-forming activity, while the Fe I line flux is consistent with the fluorescent line emission expected with the molecular clouds in the region.

Mitsuishi, Ikuyuki; Yamasaki, Noriko Y.; Takei, Yoh [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), 3-1-1 Yoshinodai, Chuo-ku Sagamihara, Kanagawa, 252-5210 (Japan)

2011-12-15

239

A generalized MoM-SPICE iterative technique for field coupling to multiconductor transmission lines in presence of complex structures  

Microsoft Academic Search

A generalized method of moments (MoM)-SPICE iterative technique for field coupling analysis of multiconductor transmission lines (MTLs) in the vicinity of complex structures is presented. Telegrapher's coupling equations are modified with additional distributed voltage and current sources for more accurate analysis of the total current induced onto transmission line bundles in the presence of complex structures. These additional voltage and

Yakup Bayram; John L. Volakis

2005-01-01

240

On-line analysis of complex hydrocarbon mixtures using comprehensive two-dimensional gas chromatography  

Microsoft Academic Search

This paper discusses the first setup for on-line qualitative and quantitative comprehensive two-dimensional gas chromatography (GC×GC) of complex hydrocarbon mixtures. A built-in 4-port 2-way valve allows switching between flame ionization detection (FID) and time-of-flight mass spectrometry (TOF-MS) between runs, without the need to cool down and vent the MS. Proper selection of GC carrier gas flow rates enables maximal agreement

Kevin M. Van Geem; Steven P. Pyl; Marie-Françoise Reyniers; Joeri Vercammen; Jan Beens; Guy B. Marin

2010-01-01

241

Input impedance of a coaxial line terminated with a complex gap capacitance - numerical and experimental analysis  

Microsoft Academic Search

A full-wave numerical analysis was performed for a coaxial line terminated with a complex gap capacitance using a finite-element high-frequency structure simulator. The scattering parameters, input impedance, and spatial distribution of the electromagnetic field have been obtained in the frequency range of 100 MHz to 19 GHz for specimens 8 to 320 ?m thick, with a dielectric constant of up

Jan Obrzut; A. Anopchenko

2004-01-01

242

The implications of gamma-ray lines observed from the Orion complex  

NASA Astrophysics Data System (ADS)

The observation of intense gamma-ray line emission from the Orion complex, attributed by Bloemen et al. to de-excitation of cosmic-ray carbon and oxygen nuclei, has important implications for emission from Orion in the infrared and in high-energy gamma-rays, and also for the theories of cosmic-ray origins. Some of these implications are briefly pointed out.

Cowsik, Ramanath; Friedlander, Michael W.

1995-05-01

243

EFFECT OF IRON COMPLEXES WITH MANNICH TYPE LIGANDS ON VIABILITY OF TUMOUR CELL LINES  

Microsoft Academic Search

The effect of three complexes of iron with Mannich type ligands were studied in vitro on animal and human tumour cells using neutral red uptake cytotoxicity assay. The following cell lines were used in the experiments - LSCC-SF- Mc29 (transplantable chicken hepatoma induced by the myelocytomatosis virus Mc29), LSR-SF-SR (transplantable sarcoma in rat induced by Rous sarcoma virus strain Schmidt-Ruppin),

R. I. Alexandrova; G. Rashkova; T. Popova; S. Slavov; N. Stefanov; E.-M. Mosoarca; R. Tudose; O. Costisor

244

2-D analysis of leakage in printed-circuit lines using discrete complex-images technique  

Microsoft Academic Search

The mixed-potential integral equation is combined with the discrete complex-images technique to analyze the complete spectrum of multilayered printed transmission lines. A relevant contribution of the present two-dimensional approach is its ability to study both the bound and leaky regimes in a very simple, systematic, and efficient way. Since the analysis is carried out in the spatial domain, this method

Joaquín Bernal; Francisco Mesa; Francisco Medina

2002-01-01

245

Structure and dynamics of alpha-tocopherol in model membranes and in solution: a broad-line and high-resolution NMR study  

SciTech Connect

Nuclear magnetic resonance has been applied to study the conformational dynamics of alpha-tocopherol (vitamin E) in solution and in model membranes. In nonviscous solution, /sup 1/H nuclear magnetic resonance (NMR) showed that alpha-tocopherol is in rapid equilibrium between two or more puckered conformers of its heterocyclic ring. The most likely conformers to be so involved are the two half-chair forms. Deuterium NMR spectra of specifically deuteriated alpha-tocopherol in multilamellar dispersions of egg phosphatidylcholine, measured in the liquid-crystalline state, were characteristic of axially symmetric motional averaging. The orientation of the rotational axis within the molecular framework was determined. Studies on oriented multilamellar membranes revealed that this axis is perpendicular to the surface of the membrane. The profile of quadrupolar splittings along the hydrophobic tail does not have a plateau, in contrast to that of the fatty acyl chains of the membrane lipids. Longitudinal relaxation times (T1) were short. The presence of a minimum in their temperature dependence shows that molecular motion with an effective correlation time tau eff approximately equal to 3 X 10(-9)s is responsible for relaxation. However, the temperatures and absolute values of the minima depend on the position of the deuterium in the molecule, demonstrating that tau eff represents a complex blend of motions.

Ekiel, I.H.; Hughes, L.; Burton, G.W.; Jovall, P.A.; Ingold, K.U.; Smith, I.C.

1988-03-08

246

A hybrid MoM-SPICE technique for field coupling analysis of transmission lines in presence of complex structures  

Microsoft Academic Search

A computationally efficient method for field coupling on multiconductor transmission lines near complex structures is proposed. Key to the method is the decomposition of the current on each transmission line into push-push and push-pull mode currents. The former accounts for the interactions between the transmission line bundle and the surrounding structure, whereas the latter corresponds current perturbation to account for

Yakup Bayram; John L. Volakis

2005-01-01

247

ON THE DIVERSITY AND COMPLEXITY OF ABSORPTION LINE PROFILES PRODUCED BY OUTFLOWS IN ACTIVE GALACTIC NUCLEI  

SciTech Connect

Understanding the origin of active galactic nucleus (AGN) absorption line profiles and their diversity could help to explain the physical structure of the accretion flow, and also to assess the impact of accretion on the evolution of the AGN host galaxies. Here, we present our first attempt to systematically address the issue of the origin of the complexities observed in absorption profiles. Using a simple method, we compute absorption line profiles against a continuum point source for several simulations of accretion disk winds. We investigate the geometrical, ionization, and dynamical effects on the absorption line shapes. We find that significant complexity and diversity of the absorption line profile shapes can be produced by the non-monotonic distribution of the wind velocity, density, and ionization state. Non-monotonic distributions of such quantities are present even in steady-state, smooth disk winds, and naturally lead to the formation of multiple and detached absorption troughs. These results demonstrate that the part of a wind where an absorption line is formed is not representative of the entire wind. Thus, the information contained in the absorption line is incomplete if not even insufficient to well estimate gross properties of the wind such as the total mass and energy fluxes. In addition, the highly dynamical nature of certain portions of disk winds can have important effects on the estimates of the wind properties. For example, the mass outflow rates can be off by up to two orders of magnitude with respect to estimates based on a spherically symmetric, homogeneous, constant velocity wind.

Giustini, Margherita [INAF-Istituto di Astrofisica Spaziale e Fisica cosmica di Bologna, via Gobetti 101, I-40129 Bologna (Italy); Proga, Daniel [Department of Physics and Astronomy, University of Nevada Las Vegas, 4505 Maryland Pkwy, Las Vegas, NV 891541-4002 (United States)

2012-10-10

248

A third broad lineage of major histocompatibility complex (MHC) class I in teleost fish; MHC class II linkage and processed genes  

Microsoft Academic Search

Most of the previously studied teleost MHC class I molecules can be classified into two broad lineages: “U” and “Z\\/ZE.” However,\\u000a database reports on genes in cyprinid and salmonid fishes show that there is a third major lineage, which lacks detailed analysis\\u000a so far. We designated this lineage “L” because of an intriguing linkage characteristic. Namely, one zebrafish L locus

Johannes Martinus Dijkstra; Takayuki Katagiri; Kazuyoshi Hosomichi; Kazuyo Yanagiya; Hidetoshi Inoko; Mitsuru Ototake; Takashi Aoki; Keiichiro Hashimoto; Takashi Shiina

2007-01-01

249

The podocyte slit diaphragm-from a thin grey line to a complex signalling hub.  

PubMed

The architectural design of our kidneys is amazingly complex, and culminates in the 3D structure of the glomerular filter. During filtration, plasma passes through a sieve consisting of a fenestrated endothelium and a broad basement membrane before it reaches the most unique part, the slit diaphragm, a specialized type of intercellular junction that connects neighbouring podocyte foot processes. When podocytes become stressed, irrespective of the causative stimulus, they undergo foot process effacement and loss of slit diaphragms-two key steps leading to proteinuria. Thus, proteinuria is the unifying denominator of a broad spectrum of podocytopathies. With the rising prevalence of chronic kidney disease and the fact that glomerular diseases account for the majority of patients with end-stage renal disease, further investigation and elucidation of this unique structure is of paramount importance. This Review recounts how perception of the slit diaphragm has changed over time as a result of intense research, from its first anatomical description as a thin intercellular connection, to an appreciation of its role as a dynamic signalling hub. These observations led to the introduction of novel concepts in podocyte biology, which could pave the way to development of highly desired, specific therapeutic strategies for glomerular diseases. PMID:23999399

Grahammer, Florian; Schell, Christoph; Huber, Tobias B

2013-09-03

250

Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. IV - Intensity variations of the optical emission lines of NGC 5548  

NASA Astrophysics Data System (ADS)

Measurements of optical emission-line flux variations based on spectra of the Seyfert galaxy NGC 5548 obtained between December 1988 and October 1989 are reported. All of the measured optical emission lines, H-alpha, H-beta, H-gamma, He I 5876, and He II 4686, exhibit the same qualitative behavior as the UV and optical continua, but with short time delays, or lags, which are different for the various lines. Cross-correlation analysis is applied to measure the lags between the various lines and the continuum. Similar lags are found with respect to the UV continuum for H-alpha and H-beta, 17 and 19 d, respectively. The lag for H-gamma is shorter (13 d), only somewhat larger than the lag measured for Ly-alpha (about 10 d). The helium lines respond to continuum variations more rapidly than the hydrogen lines, with lags of about 7 d for He II 4686 and 11 d for He I 5876.

Dietrich, M.; Kollatschny, W.; Peterson, B. M.; Bechtold, J.; Bertram, R.; Bochkarev, N. G.; Boroson, T. A.; Carone, T. E.; Elvis, M.; Filippenko, A. V.; Gaskell, C. M.; Huchra, J. P.; Hutchings, J. B.; Koratkar, A. P.; Korista, K. T.; Lame, N. J.; Laor, A.; MacAlpine, G. M.; Malkan, M. A.; Mendes de Oliveira, C.; Netzer, H.; Penfold, J.; Penston, M. V.; Perez, E.; Pogge, R. W.; Richmond, M. W.; Rosenblatt, E. I.; Shapovalova, A. I.; Shields, J. C.; Smith, H. A.; Smith, P. S.; Sun, W.-H.; Thiele, U.; Veilleux, S.; Wagner, R. M.; Wilkes, B. J.; Wills, B. J.; Wills, D.

1993-05-01

251

Structural insight into potent broad-spectrum inhibition with reversible recyclization mechanism: avibactam in complex with CTX-M-15 and Pseudomonas aeruginosa AmpC ?-lactamases.  

PubMed

Although ?-lactams have been the most effective class of antibacterial agents used in clinical practice for the past half century, their effectiveness on Gram-negative bacteria has been eroded due to the emergence and spread of ?-lactamase enzymes that are not affected by currently marketed ?-lactam/?-lactamase inhibitor combinations. Avibactam is a novel, covalent, non-?-lactam ?-lactamase inhibitor presently in clinical development in combination with either ceftaroline or ceftazidime. In vitro studies show that avibactam may restore the broad-spectrum activity of cephalosporins against class A, class C, and some class D ?-lactamases. Here we describe the structures of two clinically important ?-lactamase enzymes bound to avibactam, the class A CTX-M-15 extended-spectrum ?-lactamase and the class C Pseudomonas aeruginosa AmpC ?-lactamase, which together provide insight into the binding modes for the respective enzyme classes. The structures reveal similar binding modes in both enzymes and thus provide a rationale for the broad-spectrum inhibitory activity of avibactam. Identification of the key residues surrounding the binding pocket allows for a better understanding of the potency of this scaffold. Finally, avibactam has recently been shown to be a reversible inhibitor, and the structures provide insights into the mechanism of avibactam recyclization. Analysis of the ultra-high-resolution CTX-M-15 structure suggests how the deacylation mechanism favors recyclization over hydrolysis. PMID:23439634

Lahiri, Sushmita D; Mangani, Stefano; Durand-Reville, Thomas; Benvenuti, Manuela; De Luca, Filomena; Sanyal, Gautam; Docquier, Jean-Denis

2013-02-25

252

CSO Broadband Molecular Line Surveys II: Intial Correlation Analysis Results for Complex Organic Molecules  

NASA Astrophysics Data System (ADS)

As was presented in the previous talk, we have conducted 25 broadband line surveys of interstellar sources in the ?=1.3 mm band using the Caltech Submillimeter Observatory. Using the results from the spectral analysis of these observations, the influence of physical environment on molecular complexity can be examined. Our broader research goal is to improve astrochemical models to the point where accurate predictions of complex molecular inventory can be made based on the physical and chemical environment of a given source. The CSO observations include a statistically-significant sample of sources, cover a range of physical environments, and target selected frequency windows containing transitions from a set of known complex organic molecules. We are now analyzing these line surveys to search for correlations between the relative abundances of organic molecules and the physical properties of the source (i.e. temperature, density, mass, etc.), as well as correlations between sets of molecules. Here we present the results from the initial quantitative analysis of these surveys, as well as chemical trends that have been determiend. The implications of these results for astrochemical models will also be discussed.

Sanders, James L. Sanders, Iii; Radhuber, Mary L.; Laas, Jacob C.; Hays, Brian M.; Lis, Darek C.; Weaver, Susanna L. Widicus

2013-06-01

253

Digital in-line holography with a rectangular complex coherence factor.  

PubMed

We propose in this paper the study of a particular spatially partially coherent source applied to digital in-line holography of dense particle flow. A source with a rectangular complex coherence factor is implemented. The effects of such a source on the intensity distribution of the diffraction pattern are described. In particular, we show that this type of source allows us to eliminate the diffraction pattern along one axis while all the information about the dimension of the particle is kept along the other perpendicular axis. So particle images can be well reconstructed along one direction and the speckle can be largely limited. PMID:23292387

Remacha, Clément; Coëtmellec, Sébastien; Brunel, Marc; Lebrun, Denis

2013-01-01

254

The Broad Way  

ERIC Educational Resources Information Center

|In the world of corporate philanthropy, there are those who give to educational causes, and this article describes one such philanthropist, Eli Broad, who shares his take on schools in America. Broad is in a category unto himself not only because of the amount of money he has given--more than $280 million since 1999--but also for his unique…

Butler, Kevin

2008-01-01

255

Crystal structure of the parasite inhibitor chagasin in complex with papain allows identification of structural requirements for broad reactivity and specificity determinants for target proteases.  

PubMed

A complex of chagasin, a protein inhibitor from Trypanosoma cruzi, and papain, a classic family C1 cysteine protease, has been crystallized. Kinetic studies revealed that inactivation of papain by chagasin is very fast (k(on) = 1.5 x 10(6) M(-1) x s(-1)), and results in the formation of a very tight, reversible complex (K(i) = 36 pM), with similar or better rate and equilibrium constants than those for cathepsins L and B. The high-resolution crystal structure shows an inhibitory wedge comprising three loops, which forms a number of contacts responsible for the high-affinity binding. Comparison with the structure of papain in complex with human cystatin B reveals that, despite entirely different folding, the two inhibitors utilize very similar atomic interactions, leading to essentially identical affinities for the enzyme. Comparisons of the chagasin-papain complex with high-resolution structures of chagasin in complexes with cathepsin L, cathepsin B and falcipain allowed the creation of a consensus map of the structural features that are important for efficient inhibition of papain-like enzymes. The comparisons also revealed a number of unique interactions that can be used to design enzyme-specific inhibitors. As papain exhibits high structural similarity to the catalytic domain of the T. cruzi enzyme cruzipain, the present chagasin-papain complex provides a reliable model of chagasin-cruzipain interactions. Such information, coupled with our identification of specificity-conferring interactions, should be important for the development of drugs for treatment of the devastating Chagas disease caused by this parasite. PMID:19143838

Redzynia, Izabela; Ljunggren, Anna; Bujacz, Anna; Abrahamson, Magnus; Jaskolski, Mariusz; Bujacz, Grzegorz

2009-02-01

256

LINE-1 Retroelements Complexed and Inhibited by Activation Induced Cytidine Deaminase  

PubMed Central

LINE-1 (abbreviated L1) is a major class of retroelements in humans and mice. If unrestricted, retroelements accumulate in the cytoplasm and insert their DNA into the host genome, with the potential to cause autoimmune disease and cancer. Retroviruses and other retroelements are inhibited by proteins of the APOBEC family, of which activation-induced cytidine deaminase (AID) is a member. Although AID is mainly known for being a DNA mutator shaping the antibody repertoire in B lymphocytes, we found that AID also restricts de novo L1 integrations in B- and non-B-cell lines. It does so by decreasing the protein level of open reading frame 1 (ORF1) of both exogenous and endogenous L1. In activated B lymphocytes, AID deficiency increased L1 mRNA 1.6-fold and murine leukemia virus (MLV) mRNA 2.7-fold. In cell lines and activated B lymphocytes, AID forms cytoplasmic high-molecular-mass complexes with L1 mRNA, which may contribute to L1 restriction. Because AID-deficient activated B lymphocytes do not express ORF1 protein, we suggest that ORF1 protein expression is inhibited by additional restriction factors in these cells. The greater increase in MLV compared to L1 mRNA in AID-deficient activated B lymphocytes may indicate less strict surveillance of retrovirus.

Metzner, Mirjam; Jack, Hans-Martin; Wabl, Matthias

2012-01-01

257

LINE-1 retroelements complexed and inhibited by activation induced cytidine deaminase.  

PubMed

LINE-1 (abbreviated L1) is a major class of retroelements in humans and mice. If unrestricted, retroelements accumulate in the cytoplasm and insert their DNA into the host genome, with the potential to cause autoimmune disease and cancer. Retroviruses and other retroelements are inhibited by proteins of the APOBEC family, of which activation-induced cytidine deaminase (AID) is a member. Although AID is mainly known for being a DNA mutator shaping the antibody repertoire in B lymphocytes, we found that AID also restricts de novo L1 integrations in B- and non-B-cell lines. It does so by decreasing the protein level of open reading frame 1 (ORF1) of both exogenous and endogenous L1. In activated B lymphocytes, AID deficiency increased L1 mRNA 1.6-fold and murine leukemia virus (MLV) mRNA 2.7-fold. In cell lines and activated B lymphocytes, AID forms cytoplasmic high-molecular-mass complexes with L1 mRNA, which may contribute to L1 restriction. Because AID-deficient activated B lymphocytes do not express ORF1 protein, we suggest that ORF1 protein expression is inhibited by additional restriction factors in these cells. The greater increase in MLV compared to L1 mRNA in AID-deficient activated B lymphocytes may indicate less strict surveillance of retrovirus. PMID:23133680

Metzner, Mirjam; Jäck, Hans-Martin; Wabl, Matthias

2012-11-02

258

The Relationship of Modulation of Major Histocompatibility Complex Class I Antigens to Retrovirus Transformation in Rat Cell Lines1  

Microsoft Academic Search

The expression of major histocompatibility complex (MHC) Class I antigens has been studied, by means of monoclonal antibodies directed against nonpolymorphic determinants of MHC Class I molecules, in two epithelial differentiated cell lines (FRTL-5 clone 2 and PC clone 3) and in one fibroblast cell line (FRT Fibro) of Fischer rat thyroid origin, before and after infection with various acute

Luigi Racioppi; Ennio Carbone; Michele Grieco; Luigi Del Vecchio; Maria Teresa Berlingieri; Alfredo Fusco; Edoardo Boncinelli; Serafino Zappacosta; Silvia Fontana

1988-01-01

259

Temporal Changes in Quasar Broad Emission Line Profiles and the Gravitationally Lensed Nature of Q1634+267A,B and Q2345+007A,B  

NASA Astrophysics Data System (ADS)

Steidel & Sargent (1991a, AJ, 102, 1610) found that the spectra of the components of the close quasar pairs Q1634+267A,B and Q2345+007A,B were in each case remarkably similar (except for overall differences in brightness) but that individual broad emission lines due to Ly?, SI IV, C IV and C Ill] exhibited differences in profile or equivalent width between the A and B components. If the A and B components of these objects result from gravitational lensing of a single QSO, the difference in light travel time for the two images is roughly one year for both pairs. Accordingly, the authors suggested that observations of the spectra of single QSOs would reveal similar changes in emission line profiles and equivalent widths on a time scale of one year or less. In order to test Steidel & Sargent's (l991a) hypothesis, we obtained in 1992 high quality spectra of 30 quasars with ?em˜1 selected from the brighter QSOs in the sample of Steidel & Sargent (1991b, ApJ, 382, 433), which those authors had observed in 1989-90. The new spectra were obtained with exactly the same instrumental setup as the earlier observations. The two sets of spectra were reduced in an identical manner and then compared in order to search for changes in the strengths and profiles of the principal emission lines occurring on time scales of order one year. We find that the spectra from the two epochs are remarkably similar for all the QSOs, except for overall changes in fluxes and minor differences in continuum shape which are probably artifacts introduced by the observing procedures. However, there are also changes in the equivalent widths or shapes of the stronger emission lines on rest-frame time scales of 1-1.5 years in about two thirds of the QSOs. These observations, therefore, support the notion that Q1634+267A,B and Q2345+007A,B are gravitationally lensed and that the spectra of the components in lensed QSOs need not be exactly identical. Moreover, it should be expected that any differences between the components in such systems should change with time.

Small, Todd A.; Sargent, Wallace L. W.; Steidel, Charles C.

1997-12-01

260

A Study of Warm Clouds in the Lines of Complex Molecules  

NASA Astrophysics Data System (ADS)

We present the results of a study of a large number of molecular clouds in the lines of complex molecules, CH3OH, CH3CCH, and HC3N. Temperatures, densities and molecular abundances in the clouds have been determined both analytically (applying rotational diagrams and similar methods) and by means of statistical equilibrium calculations. In most cases we obtained gas parameters that are typical for warm clouds: temperatures 20--60 K, densities 105 - 106 cm-3, and molecular abundances that match early-time chemistry. The applicability of different molecules as diagnostic tools is discussed. It is shown that with the recently calculated collisional decay rates (Pottage et al. 2001, J. Phys. B., 34, 3313) methanol becomes a tool that can be used to determine both gas temperature and density.

Kalenskii, Sergei V.; Alakoz, Alexei V.; Promyslov, Vitaly G.

261

A CO LINE AND INFRARED CONTINUUM STUDY OF THE ACTIVE STAR-FORMING COMPLEX W51  

SciTech Connect

We present the results of an extensive observational study of the active star-forming complex W51 that was observed in the J = 2 - 1 transition of the {sup 12}CO and {sup 13}CO molecules over a 1.{sup 0}25 x 1.{sup 0}00 region with the University of Arizona Heinrich Hertz Submillimeter Telescope. We use a statistical equilibrium code to estimate physical properties of the molecular gas. We compare the molecular cloud morphology with the distribution of infrared (IR) and radio continuum sources and find associations between molecular clouds and young stellar objects (YSOs) listed in Spitzer IR catalogs. The ratios of CO lines associated with H II regions are different from the ratios outside the active star-forming regions. We present evidence of star formation triggered by the expansion of the H II regions and by cloud-cloud collisions. We estimate that about 1% of the cloud mass is currently in YSOs.

Kang, Miju; Lee, Youngung; Choi, Minho [International Center for Astrophysics, Korea Astronomy and Space Science Institute, 838 Daedeokdaero, Yuseong, Daejeon 305-348 (Korea, Republic of); Bieging, John H.; Kulesa, Craig A.; Peters, William L., E-mail: mjkang@kasi.re.k [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

2010-09-15

262

Modeling the Emergence of Complexity: Complex Systems, the Origin of Life and Interactive On-Line Art  

Microsoft Academic Search

The origin of this paper lies in the fundamental question of how complexity arose in the course of evolution and how one might construct an artistic interactive system to model and simulate this emergence of complexity. Relying on the idea that interaction and communication between entities of a system drive the emergence of structures that are more complex than the

Christa Sommerer; Laurent Mignonneau

2002-01-01

263

Broad-band beam buncher  

DOEpatents

A broad-band beam bunther is disclosed, comprising an evacuated housing, an electron gun therein for producing an electron beam, a buncher cavity having entrance and exit openings through which the beam is directed, grids across such openings, a source providing a positive DC voltage between the cavity and the electron gun, a drift tube through which the electron beam travels in passing through such cavity, grids across the ends of such drift tube, gaps being provided between the drift tube grids and the entrance and exit grids, a modulator for supplying an ultrahigh frequency modulating signal to the drift tube for producing velocity modulation of the electrons in the beam, a drift space in the housing through which the velocity modulated electron beam travels and in which the beam is bunched, and a discharge opening from such drift tube and having a grid across such opening through which the bunched electron beam is discharged into an accelerator or the like. The buncher cavity and the drift tube may be arranged to constitute an extension of a coaxial transmission line which is employed to deliver the modulating signal from a signal source. The extended transmission line may be terminated in its characteristic impedance to afford a broad-

Goldberg, D.A.; Flood, W.S.; Arthur, A.A.; Voelker, F.

1984-03-20

264

Broad Bandwidth Telecommunications Systems.  

ERIC Educational Resources Information Center

|Broad bandwidth transmission systems have been around for years. They include microwave, assorted cable systems, and recently, satellites. With the exception of some privately owned systems, broadband services have been furnished by the common carriers. Recently, a new element has been added--Cable Antenna Television (CATV) distribution systems.…

Sodolski, John

265

Gas chromatography and gateway sensors for on-line-state estimation of complex fermentations (butanol-acetone fermentation)  

Microsoft Academic Search

A fermentation system has been designed to demonstrate the use of gas chromatography (GC) for on-line monitoring of the butanol-acetone and other complex saccharolytic fermentations. Tangential flow ultrafiltration was used to sterilely and continuously obtain a cell-free filtrate from the fermentation broth for on-line GC analysis of butanol, butyrate, acetate, acetone, ethanol, and acetoin. The liquid injection system consists of

Joseph K. McLaughlin; Charles L. Meyer; Eleftherios T. Papoutsakis

1985-01-01

266

COS OBSERVATIONS OF METAL LINE AND BROAD LYMAN-{alpha} ABSORPTION IN THE MULTI-PHASE O VI AND Ne VIII SYSTEM AT z = 0.20701 TOWARD HE 0226-4110  

SciTech Connect

Observations of the QSO HE 0226-4110 (z{sub em} = 0.495) with the Cosmic Origins Spectrograph (COS) from 1134 to 1796 A with a resolution of {approx}17 km s{sup -1} and signal-to-noise ratio (S/N) per resolution element of 20-40 are used to study the multi-phase absorption system at z = 0.20701 containing O VI and Ne VIII. The system was previously studied with lower S/N observations with Far-Ultraviolet Spectroscopic Explorer (FUSE) and Space Telescope Imaging Spectrograph (STIS). The COS observations provide more reliable measures of the H I and metal lines present in the system and reveal the clear presence of broad Ly{alpha} (BLA) absorption with b = 72(+13, -6) km s{sup -1} and log N(H I) = 13.87 {+-} 0.08. Detecting BLAs associated with warm gas absorbers is crucial for determining the temperature, metallicity, and total baryonic content of the absorbers. The BLA is probably recording the trace amount of thermally broadened H I in the collisionally ionized plasma with log T {approx} 5.7 that also produces the O VI and Ne VIII absorption. The total hydrogen column in the collisionally ionized gas, log N(H) {approx} 20.1, exceeds that in the cooler photoionized gas in the system by a factor of {approx}22. The oxygen abundance in the collisionally ionized gas is [O/H] = -0.89 {+-} 0.08 {+-} 0.07. The absorber probably occurs in the circumgalactic environment (halo) of a foreground L = 0.25L{sub *} disk galaxy with an impact parameter of 109 h{sub 70}{sup -1} kpc identified by Mulchaey and Chen.

Savage, B. D. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Lehner, N. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Narayanan, A. [Indian Institute of Space Science and Technology, Thiruvananthapuram 695547, Kerala (India)

2011-12-20

267

The G305 star-forming complex: radio continuum and molecular line observations  

NASA Astrophysics Data System (ADS)

We present 109-115 GHz (3 mm) wide-field spectral line observations of 12CO, 13CO and C18O J = 1-0 molecular emission and 5.5 and 8.8 GHz (6 and 3 cm) radio continuum emission towards the high-mass star-forming complex known as G305. The morphology of G305 is dominated by a large evacuated cavity at the centre of the complex driven by clusters of O stars surrounded by molecular gas. Our goals are to determine the physical properties of the molecular environment and reveal the relationship between the molecular and ionized gas and star formation in G305. This is in an effort to characterize the star-forming environment and constrain the star formation history in an attempt to evaluate the impact of high-mass stars on the evolution of the G305 complex. Analysis of CO emission in G305 reveals 156 molecular clumps with the following physical characteristics; excitation temperatures ranging from 7 to 25 K, optical depths of 0.2-0.9, H2 column densities of 0.1-4.0 × 1022 cm-2, clump masses ranging from 102 to 104 M? and a total molecular mass of >3.5 × 105 M?. The 5.5 and 8.8 GHz radio continuum emission reveals an extended low surface brightness ionized environment within which we identify 15 large-scale features with a further eight smaller sources projected within these features. By comparing to mid-infrared emission and archival data, we identify nine H II regions, seven compact H II regions, one UC H II region and four extended regions. The total integrated flux of the radio continuum emission at 5.5 GHz is ˜180 Jy corresponding to a Lyman continuum output of 2.4 × 1050 photons s-1. We compare the ionized and molecular environment with optically identified high-mass stars and ongoing star formation, identified from the literature. Analysis of this data set reveals a star formation rate of 0.008-0.016 M? yr-1 and efficiency of 7-12 per cent, allows us to probe the star formation history of the region and discuss the impact of high-mass stars on the evolution of G305.

Hindson, L.; Thompson, M. A.; Urquhart, J. S.; Faimali, A.; Johnston-Hollitt, M.; Clark, J. S.; Davies, B.

2013-11-01

268

36Cl Exposures Ages and Equilibrium Line Altitude (ELA) of the Ampato Volcanic Complex (Southern Peru).  

NASA Astrophysics Data System (ADS)

In this work we present the results obtained from the reconstruction of the ancient glacial Equilibrium Line Altitude (paleoELA) and the dating of various glacial phases on the Ampato volcanic complex (15°24´S-15°51´S, 73° W; 6.288 m asl), in the Central Andes. In order to calculate the paleoELAs we used two methods: the Accumulation Area Ratio (AAR) and the Area X Altitude Balance Ratio (AABR). The dating was obtained by cosmogenic methods (36Cl). We sampled: 1) boulders, in a stable position, larger than 1m and located on the crest of the moraines; and 2) polished and striated bedrock outcrops, which indicate the retreat of ice. In every studied valley we found voluminous moraines related to the Local Last Glacial Maximum of the Pleistocene (LLGMP). The dating obtained from the sampled boulders ranges from 17.9 ± 0.1 to 13.6 ± 0.1 kyr. We estimate that the most significant deglaciation process started at 12 ka on the Ampato volcanic complex and adjacent areas also covered by ice, such as the Patapampa altiplano. In certain valleys we found re-advance moraines such as in Huayuray valley, located on the Northern slope of the volcanic complex, dated at 11.4 ± 0.21 kyr. The last generalised advance is related to the Little Ice Age (LIA). During this event the glaciers formed small moraines which are close to the current glacial fronts. In Huayuray valley we estimated a paleoELA (AAR) of ~5,200 m during the LLGMP asl and ~5.810 m asl during the LIA. Similar data was obtained using the AABR method: ~5.150 m asl during the LLGMP, and ~5.750 m asl during the LIA. In Mollebaya valley (East face of the volcanic complex) the paleoELA (AAR) during the LLGMP was at ~5.350 m asl and during the LIA it reached ~5.740 m asl. Using the AABR method the LLGMP and LIA paleoELAs are ~5.070 and ~5.700 m asl, respectively. In Pujro-Huayjo valley, to the Soutwest, the paleoELA (AAR) during the LLGMP was ~5.390 m asl. LIA moraines are absent in this valley. We calculated the ELA from the glacier in 1955 at ~5.725 m asl. Using the AABBR method, the ELA was lower: ~4.940 m asl during LLGMP and ~5.635 m asl in 1955. Finally, in the Mucurca valley, West face of the volcanic complex, the LLGMP paleoELA was at ~4.930 m asl and at 5.100 m asl during the most recent advance (Lateglacial phase). Using the AABR method we obtained a value of ~4.865 m asl for the LLGMP paleoELA and ~5.015 m asl for the Late glacial phase. On average the the LLGMP ELA was 5220 m asl (AAR) and 5010 m asl (AABR). Based on the modern (1955) ELA from Pujro-Hayjo valley, the LLGMP ELA lowering was ~550 m (AAR) and ~625 m (AABR). Research funded by CGL2009-7343 project, Government of Spain.

Alcalá, J.; Palacios, D.; Vázquez-Selém, L.

2012-04-01

269

Emission of complex fragments for compound nuclei formed far from the stability line for A{approx}120  

SciTech Connect

Experiments and calculations are presented for the emission of complex fragments (Z>2) from compound nuclei around mass 120 and for bombarding energies below 15 MeV/nucleon. It is shown that a strong enhancement in the emission of complex fragments (especially for Z=6) is expected for compound nuclei formed close or at the N=Z line. Several predictions are given that could be tested with the radioactive beams soon to be available. Also results from a recent experiment that utilizes the emission of complex fragments for {gamma}-ray nuclear spectroscopy studies are presented.

Gomez Del Campo, J.

1996-10-01

270

Cullins 3a and 3b assemble with members of the broad complex/tramtrack/bric-a-brac (BTB) protein family to form essential ubiquitin-protein ligases (E3s) in Arabidopsis.  

PubMed

Selective modification of proteins by ubiquitination is directed by diverse families of ubiquitin-protein ligases (or E3s). A large collection of E3s use Cullins (CULs) as scaffolds to form multisubunit E3 complexes in which the CUL binds a target recognition subcomplex and the RBX1 docking protein, which delivers the activated ubiquitin moiety. Arabidopsis and rice contain a large collection of CUL isoforms, indicating that multiple CUL-based E3s exist in plants. Here we show that Arabidopsis CUL3a and CUL3b associate with RBX1 and members of the broad complex/tramtrack/bric-a-brac (BTB) protein family to form BTB E3s. Eighty genes encoding BTB domain-containing proteins were identified in the Arabidopsis genome, indicating that a diverse array of BTB E3s is possible. In addition to the BTB domain, the encoded proteins also contain various other interaction motifs that likely serve as target recognition elements. DNA microarray analyses show that BTB genes are expressed widely in the plant and that tissue-specific and isoform-specific patterns exist. Arabidopsis defective in both CUL3a and CUL3b are embryo-lethal, indicating that BTB E3s are essential for plant development. PMID:15749712

Gingerich, Derek J; Gagne, Jennifer M; Salter, Donald W; Hellmann, Hanjo; Estelle, Mark; Ma, Ligeng; Vierstra, Richard D

2005-03-04

271

Broad host range plasmids.  

PubMed

Plasmids are and will remain important cloning vehicles for biotechnology. They have also been associated with the spread of a number of diseases and therefore are a subject of environmental concern. With the advent of sequencing technologies, the database of plasmids is increasing. It will be of immense importance to identify the various bacterial hosts in which the plasmid can replicate. The present review article describes the features that confer broad host range to the plasmids, the molecular basis of plasmid host range evolution, and applications in recombinant DNA technology and environment. PMID:23980652

Jain, Aayushi; Srivastava, Preeti

2013-09-10

272

Broad band waveguide spectrometer  

DOEpatents

A spectrometer for analyzing a sample of material utilizing a broad band source of electromagnetic radiation and a detector. The spectrometer employs a waveguide possessing an entry and an exit for the electromagnetic radiation emanating from the source. The waveguide further includes a surface between the entry and exit portions which permits interaction between the electromagnetic radiation passing through the wave guide and a sample material. A tapered portion forms a part of the entry of the wave guide and couples the electromagnetic radiation emanating from the source to the waveguide. The electromagnetic radiation passing from the exit of the waveguide is captured and directed to a detector for analysis.

Goldman, Don S. (Folsom, CA)

1995-01-01

273

Broadly tunable picosecond ir source  

DOEpatents

A picosecond traveling-wave parametric device capable of controlled spectral bandwidth and wavelength in the infrared is reported. Intense 1.064 ..mu..m picosecond pulses (1) pass through a 4.5 cm long LiNbO/sub 3/ optical parametric oscillator crystal (2) set at its degeneracy angle. A broad band emerges, and a simple grating (3) and mirror (4) arrangement is used to inject a selected narrow-band into a 2 cm long LiNbO/sub 3/ optical parametric amplifier crystal (5) along a second pump line. Typical input energies at 1.064 ..mu..m along both pump lines are 6 to 8 mJ for the oscillator and 10 mJ for the amplifier. This yields 1 mJ of tunable output in the range 1.98 to 2.38 ..mu..m which when down-converted in a 1 cm long CdSe crystal mixer (6) gives 2 ..mu..J of tunable radiation over the 14.8 to 18.5 ..mu..m region. The bandwidth and wavelength of both the 2 and 16 ..mu..m radiation output are controlled solely by the diffraction grating.

Campillo, A.J.; Hyer, R.C.; Shapiro, S.L.

1980-04-23

274

Properties of d-Electrons in Complex Salts. Part III Detailed Studies of the Line Spectra  

Microsoft Academic Search

Experimental and theoretical studies previously done on the line spectra of transition metal ions in crystals are summarized. Theoretical analyses free from any ambiguous quantities are summarized. Theoretical analyses free from any ambiguous quantities are attempted. The subjects discussed here are therefore mainly restricted to the qualitative nature of the Zeeman effects and optical anisotropies of the line spectra. Electric

Satoru Sugano

1960-01-01

275

Broad spectrum bioactive sunscreens.  

PubMed

The development of sunscreens containing reduced concentration of chemical UV filters, even though, possessing broad spectrum effectiveness with the use of natural raw materials that improve and infer UV absorption is of great interest. Due to the structural similarities between polyphenolic compounds and organic UV filters, they might exert photoprotection activity. The objective of the present research work was to develop bioactive sunscreen delivery systems containing rutin, Passiflora incarnata L. and Plantago lanceolata extracts associated or not with organic and inorganic UV filters. UV transmission of the sunscreen delivery system films was performed by using diffuse transmittance measurements coupling to an integrating sphere. In vitro photoprotection efficacy was evaluated according to the following parameters: estimated sun protection factor (SPF); Boot's Star Rating category; UVA/UVB ratio; and critical wavelength (lambda(c)). Sunscreen delivery systems obtained SPF values ranging from 0.972+/-0.004 to 28.064+/-2.429 and bioactive compounds interacted with the UV filters positive and negatively. This behavior may be attributed to: the composition of the delivery system; the presence of inorganic UV filter and quantitative composition of the organic UV filters; and the phytochemical composition of the P. incarnata L. and P. lanceolata extracts. Among all associations of bioactive compounds and UV filters, we found that the broad spectrum sunscreen was accomplished when 1.68% (w/w) P. incarnata L. dry extract was in the presence of 7.0% (w/w) ethylhexyl methoxycinnamate, 2.0% (w/w) benzophenone-3 and 2.0% (w/w) TiO(2). It was demonstrated that this association generated estimated SPF of 20.072+/-0.906 and it has improved the protective defense against UVA radiation accompanying augmentation of the UVA/UVB ratio from 0.49 to 0.52 and lambda(c) from 364 to 368.6nm. PMID:18662760

Velasco, Maria Valéria Robles; Sarruf, Fernanda Daud; Salgado-Santos, Idalina Maria Nunes; Haroutiounian-Filho, Carlos Alberto; Kaneko, Telma Mary; Baby, André Rolim

2008-07-09

276

Chemiluminescence energy transfer reaction for the on-line preparation of peroxymonocarbonate and Eu(II)-dipicolinate complex.  

PubMed

In this work, an on-line preparation of peroxymonocarbonate was formed innovatively, which offered a reliable intermediate for further investigation. The forming conditions of on-line peroxymonocarbonate ions were investigated in detail. Meanwhile, the energy transfer chemiluminescent reaction of peroxymonocarbonate and the Eu(II)-dipicolinate complex was studied. Through UV-visible absorption spectra, CL method, ESR spin-trapping technique, and mass spectrum experiments, it can be concluded that peroxymonocarbonate oxidizes Eu(II) to Eu(III), and simultaneously creates radicals. The bond rearrangement within radicals formed the singlet molecular oxygen. The energy originating from the singlet oxygen was accepted by the (Eu(III)dipic)- complex. The excited (Eu(III)dipic)- ions underwent radiative deactivation and emitted the chemiluminescence. The peroxymonocarbonate system was a simple, inexpensive, and relatively nontoxic alternative to other oxidants, and it can be used in a mild, neutral-pH environment. PMID:16759143

Liu, Meilin; Zhao, Lixia; Lin, Jin-Ming

2006-06-15

277

The complex emission-line structure in the magnetic white dwarf binary 2A 0311-227 /EF Eridani/  

NASA Astrophysics Data System (ADS)

All phases of the 81 minute orbit of the magnetic X-ray binary 2A 0311-227 are covered in a series of single-trailed spectrograms of duration 25 minutes each, and resolution 2 A. Superposition of the data shows that an extremely complex line-structure and variation exist, which are phase-locked with the orbit. Previous measures by the authors are confirmed. An improved value for the orbital period is derived by comparing observations separated by 9 months. The appearance and velocities of the lines are shown. At present, no quantitative models exist to describe the complex gas streaming. Some evidence is given that at least two regions (poles), separated by less than 180 deg, of different temperature, are present.

Hutchings, J. B.; Fisher, W. A.; Cowley, A. P.; Crampton, D.; Liller, M. H.

1982-01-01

278

The Complex Halpha Line Profile of the Bright Companion to PSR J1740-5340 in NGC 6397  

Microsoft Academic Search

We present a detailed study of the Halpha and He I spectral features of COM J1740-5340 (the companion to PSR J1740-5340 in the Galactic globular cluster NGC 6397), exploiting a series of high-resolution spectra obtained at different orbital phases. The Halpha absorption line shows a complex two-component structure, revealing that optically thin hydrogen gas resides outside the Roche lobe of

E. Sabbi; R. Gratton; F. R. Ferraro; A. Bragaglia; A. Possenti; N. D'Amico; F. Camilo

2003-01-01

279

Comparative study on genotypic and phenotypic second-line drug resistance testing of Mycobacterium tuberculosis complex isolates  

Microsoft Academic Search

The mycobacterium growth indicator tube (MGIT960) automated liquid medium testing method is becoming the international gold standard for second-line drug susceptibility testing of multidrug- and extensively drug-resistant Mycobacterium tuberculosis complex isolates. We performed a comparative study of the current gold standard in the Netherlands, the Middlebrook 7H10 agar dilution method, the MGIT960 system, and the GenoType MTBDRsl genotypic method for

J. van Ingen; S. O. Simons; R. de Zwaan; T. van der Laan; M. Kamst-van Agterveld; M. J. Boeree; D. van Soolingen

2010-01-01

280

A grid-enabled time domain transmission line matrix (TLM-G) system for the analysis of complex electromagnetic structures  

Microsoft Academic Search

A Grid-enabled time domain Transmission Line Matrix (TLM-G) system for full-wave analysis of complex electromagnetic structures is presented. The emerging Grid technology enables distributed EM simulation in a Virtual Organization (VO). The Virtual Organization is a dynamic collection of resources, individuals and institutions. The layout of the TLM-G system is presented and its scalability in terms of computational time is

Petr Lorenz; JosVagner Vital; Bruno Biscontini; Peter Russer

2005-01-01

281

Evidence for Cell-Surface Association Between Fusin and the CD4-gp 120 Complex in Human Cell Lines  

Microsoft Academic Search

Accessory cell-surface molecules involved in the entry of human immunodeficiency virus-type 1 into cells have recently been identified and shown to belong to the family of chemokine receptors. Treatment of human cell lines with soluble monomeric gp 120 at 37^circC induced an association between the surface CD4-gp120 complex and a 45-kilodalton protein, which can be down-modulated by the phorbol ester

Cheryl K. Lapham; Jun Ouyang; Bhaskar Chandrasekhar; Nga Y. Nguyen; Dimiter S. Dimitrov; Hana Golding

1996-01-01

282

Expression of Major Histocompatibility Complex Class I Antigens in Normal and Transformed Rat Thyroid Epithelial Cell Lines1  

Microsoft Academic Search

Recent evidence suggests that the expression of abnormally high amounts of major histocompatibility complex (MIK.') class I molecules may be a feature of at least some kinds of transformed cells. To investigate this aspect of neoplastic transformation we studied the expression of M11Cclass I antigens in an experimental model of normal, tumor-derived, and virus-transformed thyroid epithelial cell lines. The expression

Silvia Fontana; Luigi Del Vecchio; Luigi Racioppi; Ennio Carbone; Antonio Pinto; Giulia Colletta; Serafino Zappacosta

1987-01-01

283

A Novel gamma d\\/n, RLCG Transmission Line Model Considering Complex RC(L) Loads  

Microsoft Academic Search

In deep-submicrometer integrated circuits, inductance effects have become increasingly significant, and interconnects are often modeled as transmission lines. An equivalent circuit model, which is called the gammad\\/n model and regularly constructed by two elementary resistance-capacitance-inductance-conductance cells, is proposed for transmission line modeling in this paper. Unlike those moment-matching techniques, the gammad\\/n model is a physical model in nature, and it

Saihua Lin; Huazhong Yang; Rong Luo

2007-01-01

284

Data Mining of NCI's Anticancer Screening Database Reveals Mitochondrial Complex I Inhibitors Cytotoxic to Leukemia Cell Lines  

PubMed Central

Mitochondria are principal mediators of apoptosis and thus can be considered molecular targets for new chemotherapeutic agents in the treatment of cancer. Inhibitors of mitochondrial complex I of the electron transport chain have been shown to induce apoptosis and exhibit antitumor activity. In an effort to find novel complex I inhibitors which exhibited anti-cancer activity in the NCI’s tumor cell line screen, we examined organized tumor cytotoxicity screening data available as SOM (self-organized maps) (http://spheroid.ncifcrf.gov) at the Developmental Therapeutics Program (DTP) of the National Cancer Institute (NCI). Our analysis focused on an SOM cluster comprised of compounds which included a number of known mitochondrial complex I (NADH:CoQ oxidoreductase) inhibitors. From these clusters ten compounds whose mechanism of action was unknown were tested for inhibition of complex I activity in bovine heart submitochondrial particles (SMP) resulting in the discovery that five of the ten compounds demonstrated significant inhibition with IC50's in the nM range for three of the five. Examination of screening profiles of the five inhibitors toward the NCI’s tumor cell lines revealed that they were cytotoxic to the leukemia subpanel (particularly K562 cells). Oxygen consumption experiments with permeabilized K562 cells revealed that the five most active compounds inhibited complex I activity in these cells in the same rank order and similar potency as determined with bovine heart SMP. Our findings thus fortify the appeal of mitochondrial Complex I as a possible anti-cancer molecular target and provide a data mining strategy for selecting candidate inhibitors for further testing.

Glover, Constance J.; Rabow, Alfred A.; Isgor, Yasemin G.; Shoemaker, Robert H.; Covell, David G.

2007-01-01

285

Complex-valued transmission-line parameters and their relation to the radiation resistance  

Microsoft Academic Search

In this paper, the telegrapher equations are extended to general modes and very high frequencies to include radiation effects. It is shown, that the new line parameters are gauge dependent. However, there is also a gauge-independent representation of these parameters. In this representation, the per-unit-length capacitance is not correlated with the radiation resistance, only the per-unit-length inductance (strictly speaking, the

Jürgen B. Nitsch; Sergey V. Tkachenko

2004-01-01

286

Locating sea-sky line in infrared image based on complex degree calculation  

Microsoft Academic Search

Research on the location of sea-sky line under infrared complicated sea-sky background has the important value to improve the capability of far target recognition. In a real sea-sky background infrared image, the sky and the sea normally appear in the form of different changes of grey-level on account of their different infrared radiation and reflection characteristics. So we can use

Peng Wang; Jinwen Tian; Chenqiang Gao

2009-01-01

287

Modulational instability in a purely nonlinear coupled complex Ginzburg-Landau equations through a nonlinear discrete transmission line  

NASA Astrophysics Data System (ADS)

We study wave propagation in a nonlinear transmission line with dissipative elements. We show analytically that the telegraphers' equations of the electrical transmission line can be modeled by a pair of continuous coupled complex Ginzburg-Landau equations, coupled by purely nonlinear terms. Based on this system, we investigated both analytically and numerically the modulational instability (MI). We produce characteristics of the MI in the form of typical dependence of the instability growth rate on the wavenumbers and system parameters. Generic outcomes of the nonlinear development of the MI are investigated by dint of direct simulations of the underlying equations. We find that the initial modulated plane wave disintegrates into waves train. An apparently turbulent state takes place in the system during the propagation.

Ndzana, Fabien, II; Mohamadou, Alidou; Kofané, Timoléon C.

2008-12-01

288

Manipulation of a Schlenk Line: Preparation of Tetrahydrofuran Complexes of Transition-Metal Chlorides  

ERIC Educational Resources Information Center

|Before taking an inorganic laboratory course few students have experience handling air-sensitive materials using Schlenk techniques. This exercise introduces them to techniques they will employ in later syntheses. The procedure involves the formation of anhydrous tetrahydrofuran complexes of transition-metal chlorides from metal-chloride…

Davis, Craig M.; Curran, Kelly A.

2007-01-01

289

Complete complex conjugate resolved heterodyne swept source optical coherence tomography using a dispersive optical delay line: erratum  

PubMed Central

We correct an error in our previous paper [Biomed. Opt. Express 2, 1218 (2011)] which led to an erroneous conclusion that a dispersive optical delay line (DODL) used in a swept source optical coherence tomography (SSOCT) system generated a pure phase modulation allowing for complex conjugate artifact removal in Fourier domain OCT via optical heterodyning. We now understand that an alternate phenomenon known as coherence revival was responsible for the observed phase modulation, while the DODL provided a compact means of generating a large group delay with readily adjustable group velocity dispersion compensation.

Dhalla, Al-Hafeez; Izatt, Joseph A.

2012-01-01

290

Response to ICRF-159 in cell lines resistant to cleavable complex-forming topoisomerase II inhibitors.  

PubMed Central

We have studied the relationship between expression of genes implicated in mediating resistance to cleavable complex-forming topoisomerase II (topo II) inhibitors and cellular sensitivity to ICRF-159, a 'catalytic' inhibitor of topo II. Overexpression of the membrane transporters, P-glycoprotein and multidrug resistance-related protein (MRP), or down-regulation of topo IIalpha and/or -beta, did not confer ICRF-159 resistance. Indeed, marked topo IIalpha down-regulation appeared to be associated with collateral sensitivity to ICRF-159. Our results indicate that the resistance mechanisms that pertain to cleavable complex-forming topo II inhibitors and ICRF-159 are distinct. The evidence presented here suggests that topo IIalpha, not topo IIbeta, is more likely to be the major in vivo target for ICRF-159. Images Figure 1 Figure 2

Davies, S. L.; Bergh, J.; Harris, A. L.; Hickson, I. D.

1997-01-01

291

The mouse nac1 gene, encoding a cocaine-regulated Bric-a-brac Tramtrac Broad complex/Pox virus and Zinc finger protein, is regulated by AP1.  

PubMed

NAC1 cDNA was identified as a novel transcript induced in the nucleus accumbens from rats chronically treated with cocaine. NAC1 is a member of the Bric-a-brac Tramtrac Broad complex/Pox virus and Zinc finger family of transcription factors and has been shown by overexpression studies to prevent the development of behavioral sensitization resulting from repeated cocaine treatment. This paper reports the cloning and characterization of the corresponding gene. The mouse Nac1 gene consist of six exons, with exon 2 containing an alternative splice donor, providing a molecular explanation of the splice variants observed in mouse and rat. Transcripts of Nac1 were ubiquitously detected in different mouse tissues with prominent expression in the brain. The mouse Nac1 gene was localized to chromosome 8, suggesting a highly plausible candidate gene to explain differences in cocaine-induced behaviors between C57BL6/J and DBA/2J mice that had previously been mapped to the area. In addition, a functional AP1 binding site has been identified in an intron 1 enhancer of the Nac1 gene that plays an essential role in the activation of the gene in differentiation of neuroblastoma cells. Co-transfection with c-jun and c-fos expression plasmids, which encode the two subunits of AP1, activated the wild type Nac1 intron 1 enhancer two-fold over basal, nearly at the level of NAC1 enhancer activity seen in differentiated N2A cells. Mutation of the AP1 site completely abrogated all activation of the NAC1 enhancer in differentiated N2A cells. Activation of immediate early genes such as c-fos and c-jun following chronic drug treatments has been well characterized. The present data describe one potential regulatory cascade involving these transcription factors and activation of NAC1. Identification of drug induced alterations in gene expression is key to understanding the types of molecular adaptations underlying addiction. PMID:14521994

Mackler, S A; Homan, Y X; Korutla, L; Conti, A C; Blendy, J A

2003-01-01

292

On-line multidimensional liquid chromatographic determination of polynuclear aromatic hydrocarbons in complex samples  

SciTech Connect

A method is described for the on-line coupling of a normal-phase high-performance liquid chromatographic (HPLC) system to a reversed-phased HPLC system. The method employs a diamine column for on-column concentration of a selected fraction from a normal-phase aminosilane column followed by a solvent exchange procedure and gradient elution focusing of the analyte species onto a reversed-phase octadecyisilane column. No loss of analyte of chromatographic resolution is observed by using this method. Several chromatographic packing materials were investigated for use as on-column concentrators of polynuclear aromatic hydrocarbons (PAH) from normal-phase chromatographic systems. The validity of this approach was verified by determining the concentration of several PAH in Standard Reference Material (SRM) 1580 - ''Organics in Shale Oil''. 4 figures, 3 tables.

Sonnefeld, W.J. (Univ. of Maryland, College Park); May, W.E., Wise, S.A.

1982-04-01

293

Line narrowing spectroscopic studies of DNA-carcinogen adducts and DNA-dye complexes  

SciTech Connect

Laser-induced fluorescence line narrowing and non-line narrowing spectroscopic methods were applied to conformational studies of stable DNA adducts of the 7{beta}, 8{alpha}-dihydoxy-9{alpha}, l0{alpha}-epoxy-7,8,9, 10-tetrahydrobenzo[{alpha}]pyrene (anti-BPDE). Stereochemically distinct (+)-trans-, ({minus})-trans-, (+)-cis- and ({minus})-cis adducts of anti-BPDE bound to exocyclic amino group of the central guanine in an 11-mer oligonucleotide, exist in a mixture of conformations in frozen aqueous buffer matrices. The (+)-trans adduct adopts primarily an external conformation with a smaller fraction ( {approximately} 25 %) exists in a partially base-stacked conformation. Both cis adducts were found to be intercalated with significant {pi}-{pi} stacking interactions between the pyrenyl residues and the bases. Conformations of the trans-adduct of (+)-anti -BPDE in 11-mer oligonucleotides were studied as a function of flanking bases. In single stranded form the adduct at G{sub 2} or G{sub 3} (5 ft-flanking, base guanine) adopts a conformation with strong, interaction with the bases. In contrast, the adduct with a 5ft-flanking, thymine exists in a primarily helixexternal conformation. Similar differences were observed in the double stranded oligonucleotides. The nature of the 3ft-flanking base has little influence on the conformational equilibrium of the (+)-trans-anti BPDE-dG adduct. The formation and repair of BPDE-N{sup 2}-dG in DNA isolated from the skin of mice treated topically with benzo[{alpha}]pyrene (BP) was studied. Low-temperature fluorescence spectroscopy of the intact DNA identified the major adduct as (+)-trans-anti-BPDE-N-dG, and the minor adduct fraction consisted mainly of (+)-cis-anti-BPDE-N{sup 2}-dG.

Suh, Myungkoo

1995-12-06

294

COMPLEX STRUCTURE IN CLASS 0 PROTOSTELLAR ENVELOPES. II. KINEMATIC STRUCTURE FROM SINGLE-DISH AND INTERFEROMETRIC MOLECULAR LINE MAPPING  

SciTech Connect

We present a study of dense molecular gas kinematics in 17 nearby protostellar systems using single-dish and interferometric molecular line observations. The non-axisymmetric envelopes around a sample of Class 0/I protostars were mapped in the N{sub 2}H{sup +} (J = 1 {yields} 0) tracer with the IRAM 30 m, CARMA, and Plateau de Bure Interferometer, as well as NH{sub 3} (1,1) with the Very Large Array. The molecular line emission is used to construct line-center velocity and linewidth maps for all sources to examine the kinematic structure in the envelopes on spatial scales from 0.1 pc to {approx}1000 AU. The direction of the large-scale velocity gradients from single-dish mapping is within 45{sup 0} of normal to the outflow axis in more than half the sample. Furthermore, the velocity gradients are often quite substantial, the average being {approx}2.3 km s{sup -1} pc{sup -1}. The interferometric data often reveal small-scale velocity structure, departing from the more gradual large-scale velocity gradients. In some cases, this likely indicates accelerating infall and/or rotational spin-up in the inner envelope; the median velocity gradient from the interferometric data is {approx}10.7 km s{sup -1} pc{sup -1}. In two systems, we detect high-velocity HCO{sup +} (J = 1 {yields} 0) emission inside the highest-velocity N{sub 2}H{sup +} emission. This enables us to study the infall and rotation close to the disk and estimate the central object masses. The velocity fields observed on large and small scales are more complex than would be expected from rotation alone, suggesting that complex envelope structure enables other dynamical processes (i.e., infall) to affect the velocity field.

Tobin, John J.; Hartmann, Lee; Bergin, Edwin A. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Chiang, Hsin-Fang; Looney, Leslie W. [Department of Astronomy, University of Illinois, Urbana, IL 61801 (United States); Chandler, Claire J. [National Radio Astronomy Observatory, Socorro, NM 87801 (United States); Masque, Josep M. [Departament d'Astronomia i Meteorologia, Universitat de Barcelona, 08028 Barcelona, Catalunya (Spain); Maret, Sebastien [UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d'Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble F-38041 (France); Heitsch, Fabian, E-mail: jjtobin@umich.edu [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599 (United States)

2011-10-10

295

Characterization of the androgen-sensitive MDA-kb2 cell line for assessing complex environmental mixtures.  

PubMed

Synthetic and natural steroidal androgens and estrogens and many other non-steroidal endocrine-active compounds commonly occur as complex mixtures in aquatic environments. It is important to understand the potential interactive effects of these mixtures to properly assess their risk. Estrogen receptor agonists exhibit additivity in mixtures when tested in vivo and in vitro. Little is known, however, concerning possible mixture interactions of androgen receptor agonists. In these studies we used the MDA-kb2 cell line, a human breast cancer cell line with endogenous androgen receptors and a stably transfected luciferase reporter gene construct to quantify the androgenic activity of seven natural and synthetic androgens: 17beta-trenbolone, dihydrotestosterone, methyltestosterone, testosterone, trendione, 17alpha-trenbolone, and androstenedione. We tested combinations of these androgens and compared the observed activity to expected androgenic activity based on a concentration addition model. Our analyses support the hypothesis that androgen receptor agonists cause additive responses in a mixture. Binary mixtures of 17beta-trenbolone with 17beta-estradiol or triclocarban (an anti-microbial found in the environment) were also tested. 17beta-Estradiol induced androgenic activity, but only at concentrations 600-fold greater than those found in the environment. Triclocarban enhanced the activity of 17beta-trenbolone. Additionally, three anti-androgens were each paired with three androgens of varying potencies. The relative potencies of the antagonists were a vinclozolin metabolite (M2) > procymidone > prochloraz regardless of the androgen used. The results of our studies demonstrate the potential utility of the androgen-responsive MDA-kb2 cell line for quantifying the activity of mixtures of endocrine-active chemicals in complex wastes such as municipal effluents and feedlot discharges. PMID:20821581

Blake, Lindsey S; Martinovi?, Dalma; Gray, L Earl; Wilson, Vickie S; Regal, Ron R; Villeneuve, Daniel L; Ankley, Gerald T

2010-06-01

296

GENE EXPRESSION PROFILES OF TWO B-COMPLEX DISPARATE, GENETICALLY INBRED FAYOUMI CHICKEN LINES THAT DIFFER IN SUSCEPTIBILITY TO EIMERIA MAXIMA  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study was conducted to discriminate the gene expression profiles following Eimeria maxima infection between two B complex congenic lines (lines M5.1 and M15.2) of Fayoumi chickens which display differences in disease resistance and innate immunity against avian coccidiosis. A cDNA microarray, ...

297

GENE EXPRESSION PROFILES OF TWO B-COMPLEX DISPARATE, GENETICALLY INBRED FAYOUMI CHICKEN LINES THAT DIFFER IN SUSCEPTIBILITY TO EIMERIA MAXIMA  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study was conducted to compare the gene expression profiles following Eimeria maxima infection between two B-complex congenic lines (lines M5.1 and M15.2) of Fayoumi chickens which display differences in disease resistance and innate immunity against avian coccidiosis. A cDNA microarray, const...

298

Analysis of storage proteins (prolamines, puroindolines and Waxy) in common wheat lines Triticum aestivum L. × ( Triticum timopheevii Zhuk. × Triticum tauschii ) with complex resistance to fungal infections  

Microsoft Academic Search

Storage proteins (prolamines, puroindolines, and Waxy) were studied in common wheat introgression lines obtained with the\\u000a use of the Saratovskaya 29 (S29) cultivar line and synthetic hexaploid wheat (Triticum timopheevii Zhuk. × T. tauschii) (Sintetik, Sin.) displaying complex resistance to fungal infections. Comparative analysis of storage proteins in the introgression\\u000a lines of common wheat Triticum aestivum L. and in the

L. V. Obukhova; L. I. Laikova; V. K. Shumny

2010-01-01

299

Steps toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XII. Ground-based Monitoring of 3C 390.3  

Microsoft Academic Search

Results of a ground-based optical monitoring campaign on 3C 390.3 in 1994-1995 are presented. The broadband fluxes (B, V, R, and I), the spectrophotometric optical continuum flux F lambda (5177 A), and the integrated emission-line fluxes of H alpha , H beta , H gamma , He I lambda 5876, and He II lambda 4686 all show a nearly monotonic

M. Dietrich; B. M. Peterson; P. Albrecht; M. Altmann; A. J. Barth; P. J. Bennie; R. Bertram; N. G. Bochkarev; H. Bock; J. M. Braun; A. Burenkov; S. Collier; L.-Z. Fang; O. P. Francis; A. V. Filippenko; C. B. Foltz; W. Gaessler; C. M. Gaskell; M. Geffert; K. K. Ghosh; R. W. Hilditch; R. K. Honeycutt; K. Horne; J. P. Huchra; S. Kaspi; M. Kuemmel; K. M. Leighly; D. C. Leonard; Yu. F. Malkov; V. Mikhailov; H. R. Miller; A. C. Morrill; J. Noble; P. T. O'Brien; T. D. Oswalt; S. P. Pebley; M. Pfeiffer; V. I. Pronik; B.-C. Qian; J. W. Robertson; A. Robinson; K. S. Rumstay; J. Schmoll; S. G. Sergeev; E. A. Sergeeva; A. I. Shapovalova; D. R. Skillman; S. A. Snedden; S. Soundararajaperumal; G. M. Stirpe; J. Tao; G. W. Turner; R. M. Wagner; S. J. Wagner; J. Y. Wei; H. Wu; W. Zheng; Z. L. Zou

1998-01-01

300

Complete complex conjugate resolved heterodyne swept-source optical coherence tomography using a dispersive optical delay line  

PubMed Central

Swept-source optical coherence tomography (SSOCT) provides a substantial sensitivity advantage over its time-domain counterpart, but suffers from a reduced imaging depth range due to sensitivity falloff and complex conjugate ambiguity. Heterodyne complex conjugate-resolved SSOCT (HCCR-SSOCT) has been previously demonstrated as a technique to completely resolve the complex conjugate ambiguity, effectively doubling the falloff limited imaging depth, without the reduction in imaging speed associated with other CCR techniques. However, previous implementations of this technique have employed expensive and lossy optical modulators to provide the required differential phase modulation. In this paper, we demonstrate the use of a dispersive optical delay line (D-ODL) as the reference arm of an OCT system to realize HCCR-SSOCT. This technique maintains the existing advantages of HCCR-SSOCT in that it completely resolves the complex conjugate artifact and does not reduce imaging speed, while conferring the additional advantages of being low cost, maintaining system sensitivity and resolution, not requiring any additional signal processing, and working at all wavelengths and imaging speeds. The D-ODL also allows for hardware correction of unbalanced dispersion in the reference and sample arm, adding further flexibility to system design. We demonstrate the technique using an SSOCT system operating at 100kHz with a central wavelength of 1040nm. Falloff measurements performed using a standard OCT configuration and the proposed D-ODL demonstrate a doubling of the effective imaging range with no sensitivity or resolution penalty. Feasibility of the technique for in vivo imaging was demonstrated by imaging the ocular anterior segments of healthy human volunteers.

Dhalla, Al-Hafeez; Izatt, Joseph A.

2011-01-01

301

The Broad Autism Phenotype Questionnaire  

Microsoft Academic Search

The broad autism phenotype (BAP) is a set of personality and language characteristics that reflect the phenotypic expression\\u000a of the genetic liability to autism, in non-autistic relatives of autistic individuals. These characteristics are milder but\\u000a qualitatively similar to the defining features of autism. A new instrument designed to measure the BAP in adults, the Broad\\u000a Autism Phenotype Questionnaire (BAPQ), was

Robert S. E. Hurley; Molly Losh; Morgan Parlier; J. Steven Reznick; Joseph Piven

2007-01-01

302

HST/COS OBSERVATIONS OF GALACTIC HIGH-VELOCITY CLOUDS: FOUR ACTIVE GALACTIC NUCLEUS SIGHT LINES THROUGH COMPLEX C  

SciTech Connect

We report ultraviolet spectra of Galactic high-velocity clouds (HVCs) in Complex C, taken by the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST), together with new 21 cm spectra from the Green Bank Telescope. The wide spectral coverage and higher signal-to-noise ratio, compared to previous HST spectra, provide better velocity definition of the HVC absorption, additional ionization species (including high ions), and improved abundances in this halo gas. Complex C has a metallicity of 10%-30% solar and a wide range of ions, suggesting dynamical and thermal interactions with hot gas in the Galactic halo. Spectra in the COS medium-resolution G130M (1133-1468 A) and G160M (1383-1796 A) gratings detect ultraviolet absorption lines from eight elements in low-ionization states (O I, N I, C II, S II, Si II, Al II, Fe II, P II) and three elements in intermediate- and high-ionization states (Si III, Si IV, C IV, N V). Our four active galactic nucleus sight lines toward Mrk 817, Mrk 290, Mrk 876, and PG 1259+593 have high-velocity H I and O VI column densities, log N{sub Hi}= 19.39-20.05 and log N{sub Ovi}= 13.58-14.10, with substantial amounts of kinematically associated photoionized gas. The high-ion abundance ratios are consistent with cooling interfaces between photoionized and collisionally ionized gas: N(C IV)/N(O VI) {approx} 0.3-0.5, N(Si IV)/N(O VI) {approx} 0.05-0.11, N(N V)/N(O VI) {approx} 0.07-0.13, and N(Si IV)/N(Si III) {approx}0.2.

Shull, J. Michael; Stevans, Matthew; Danforth, Charles; Penton, Steven V. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Lockman, Felix J. [National Radio Astronomy Observatory, Green Bank, WV 29444 (United States); Arav, Nahum, E-mail: michael.shull@colorado.edu, E-mail: matthew.stevans@colorado.edu, E-mail: charles.danforth@colorado.edu, E-mail: steven.penton@colorado.edu, E-mail: jlockman@nrao.edu, E-mail: arav@vt.edu [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States)

2011-10-01

303

Fluorescence-Tagged Transgenic Lines Reveal Genetic Defects in Pollen Growth--Application to the Eif3 Complex  

PubMed Central

Background Mutations in several subunits of eukaryotic translation initiation factor 3 (eIF3) cause male transmission defects in Arabidopsis thaliana. To identify the stage of pollen development at which eIF3 becomes essential it is desirable to examine viable pollen and distinguish mutant from wild type. To accomplish this we have developed a broadly applicable method to track mutant alleles that are not already tagged by a visible marker gene through the male lineage of Arabidopsis. Methodology/Principal Findings Fluorescence tagged lines (FTLs) harbor a transgenic fluorescent protein gene (XFP) expressed by the pollen-specific LAT52 promoter at a defined chromosomal position. In the existing collection of FTLs there are enough XFP marker genes to track nearly every nuclear gene by virtue of its genetic linkage to a transgenic marker gene. Using FTLs in a quartet mutant, which yields mature pollen tetrads, we determined that the pollen transmission defect of the eif3h-1 allele is due to a combination of reduced pollen germination and reduced pollen tube elongation. We also detected reduced pollen germination for eif3e. However, neither eif3h nor eif3e, unlike other known gametophytic mutations, measurably disrupted the early stages of pollen maturation. Conclusion/Significance eIF3h and eIF3e both become essential during pollen germination, a stage of vigorous translation of newly transcribed mRNAs. These data delimit the end of the developmental window during which paternal rescue is still possible. Moreover, the FTL collection of mapped fluorescent protein transgenes represents an attractive resource for elucidating the pollen development phenotypes of any fine-mapped mutation in Arabidopsis.

Roy, Bijoyita; Copenhaver, Gregory P.; von Arnim, Albrecht G.

2011-01-01

304

On-line redox derivatization liquid chromatography for selective separation of Fe(II) and Fe(III) cyanide complexes using porous graphitic carbon.  

PubMed

On-line redox derivatization HPLC was applied for the analysis of Fe(II) and Fe(III) cyanide complexes. The HPLC system used consisted of two C18 silica columns treated with trimethylstearylammonium chloride and a small column packed with porous graphitic carbon (PGC) placed between them. The PGC column treated with sodium sulfite completely reduced the Fe(III) cyanide complex to the Fe(II) complex, while the Fe(II) cyanide complex was converted to the Fe(III) complex by the PGC column treated with hydrogen peroxide. On the other hand, the oxidation states of the other metal cyanide complexes were not affected by PGC. Selective separations of the Fe(II) and Fe(III) cyanide complexes from the other metal complexes were demonstrated by on-line redox derivatization HPLC using the oxidized and reduced PGC column as the redox derivatization unit, respectively. The method was successfully applied for the analysis of Fe(II) cyanide complex in food grade salt. PMID:23842414

Saitoh, Kazunori; Soeta, Naoki; Minamisawa, Hiroaki; Shibukawa, Masami

2013-01-01

305

Determination of polycyclic aromatic hydrocarbons in edible oils and fats by on-line donor-acceptor complex chromatography and high-performance liquid chromatography with fluorescence detection  

Microsoft Academic Search

Various off-line methods for clean-up and sample enrichment are available for the analysis of polycyclic aromatic hydrocarbons (PAHs) in edible oils and fats. These methods consist of laborious and time consuming procedures. This study reports an on-line method using LC-LC coupling. After clean-up of the sample on a donor-acceptor complex chromatography (DACC) column the PAHs are transferred to and separated

F. van Stijn; M. A. T. Kerkhoff; B. G. M. Vandeginste

1996-01-01

306

Elucidation of complex decay schemes using on-line mass separated sources and a large array of Compton-suppressed germanium detectors  

Microsoft Academic Search

Complex decay scheme construction using beta decay of isotopes produced by spallation and mass separation on-line at TRIUMF-ISAC and studied with the 8pi array of 20 Compton-suppressed germanium detectors is described. Results from the analysis of the ^160Yb -> ^160Tm decay will be presented. Emphasis will be placed on the sensitivity to weak decay branches, assignment of gamma-ray lines to

N. Brown; J. L. Wood; W. D. Kulp; D. Furse; G. A. Demand; P. E. Garrett; K. L. Green; G. F. Grinyer; K. G. Leach; A. A. Phillips; M. A. Schumaker; C. E. Svensson; J. Wong; G. C. Ball; D. S. Bandyopadhyay; G. Hackman; A. C. Morton; C. J. Pearson; R. A. E. Austin; S. Colosimo; S. W. Yates; D. Cross

2008-01-01

307

The induced magnetic field calculation of three phase overhead transmission lines above a lossy ground as a frequency-dependent complex function  

Microsoft Academic Search

This paper presents a calculation of the induced magnetic field which is generated by high voltage, super-high voltage and extra high voltage transmission lines. The frequency-dependent model considers self and mutual impedances of transmission lines, taking into account the influence of bundled conductors using a sag in one span, ground-return path with earth resistivity which is as a frequency-dependent complex

Vu Phan Tu; J. Tlusty

2003-01-01

308

The Broad Autism Phenotype Questionnaire  

ERIC Educational Resources Information Center

|The broad autism phenotype (BAP) is a set of personality and language characteristics that reflect the phenotypic expression of the genetic liability to autism, in non-autistic relatives of autistic individuals. These characteristics are milder but qualitatively similar to the defining features of autism. A new instrument designed to measure the…

Hurley, Robert S. E.; Losh, Molly; Parlier, Morgan; Reznick, J. Steven; Piven, Joseph

2007-01-01

309

The Broad Superintendents Academy, 2007  

ERIC Educational Resources Information Center

The Broad Superintendents Academy is an executive training program that identifies and prepares prominent leaders--executives with experience successfully leading large organizations and a passion for public service--then places them in urban school districts to dramatically improve the quality of education for America's students. This brochure…

Broad Foundation, 2007

2007-01-01

310

Broad-Band Directional Couplers  

Microsoft Academic Search

It is shown how to connect two identical hybrids to obtain a directional coupler of arbitrary power division that operates over a broader band than that of the components. The broad-banding technique is possible with a certain kind of hybrid that includes Riblet couplers, multihole hybrids, coaxial hybrids and semioptical hybrids, but excludes T hybrids and ring hybrids. Riblet couplers

E. A. Marcatili; D. H. Ring

1962-01-01

311

Research on infrared dim-point target detection and tracking under sea-sky-line complex background  

NASA Astrophysics Data System (ADS)

Target detection and tracking technology in infrared image is an important part of modern military defense system. Infrared dim-point targets detection and recognition under complex background is a difficulty and important strategic value and challenging research topic. The main objects that carrier-borne infrared vigilance system detected are sea-skimming aircrafts and missiles. Due to the characteristics of wide field of view of vigilance system, the target is usually under the sea clutter. Detection and recognition of the target will be taken great difficulties .There are some traditional point target detection algorithms, such as adaptive background prediction detecting method. When background has dispersion-decreasing structure, the traditional target detection algorithms would be more useful. But when the background has large gray gradient, such as sea-sky-line, sea waves etc .The bigger false-alarm rate will be taken in these local area .It could not obtain satisfactory results. Because dim-point target itself does not have obvious geometry or texture feature ,in our opinion , from the perspective of mathematics, the detection of dim-point targets in image is about singular function analysis .And from the perspective image processing analysis , the judgment of isolated singularity in the image is key problem. The foregoing points for dim-point targets detection, its essence is a separation of target and background of different singularity characteristics .The image from infrared sensor usually accompanied by different kinds of noise. These external noises could be caused by the complicated background or from the sensor itself. The noise might affect target detection and tracking. Therefore, the purpose of the image preprocessing is to reduce the effects from noise, also to raise the SNR of image, and to increase the contrast of target and background. According to the low sea-skimming infrared flying small target characteristics , the median filter is used to eliminate noise, improve signal-to-noise ratio, then the multi-point multi-storey vertical Sobel algorithm will be used to detect the sea-sky-line ,so that we can segment sea and sky in the image. Finally using centroid tracking method to capture and trace target. This method has been successfully used to trace target under the sea-sky complex background.

Dong, Yu-Xing; Li, Yan; Zhang, Hai-Bo

2011-06-01

312

The Use of Genome-Wide eQTL Associations in Lymphoblastoid Cell Lines to Identify Novel Genetic Pathways Involved in Complex Traits  

Microsoft Academic Search

The integrated analysis of genotypic and expression data for association with complex traits could identify novel genetic pathways involved in complex traits. We profiled 19,573 expression probes in Epstein-Barr virus-transformed lymphoblastoid cell lines (LCLs) from 299 twins and correlated these with 44 quantitative traits (QTs). For 939 expressed probes correlating with more than one QT, we investigated the presence of

Josine L. Min; Jennifer M. Taylor; J. Brent Richards; Tim Watts; Fredrik H. Pettersson; John Broxholme; Kourosh R. Ahmadi; Gabriela L. Surdulescu; Ernesto Lowy; Christian Gieger; Chris Newton-Cheh; Markus Perola; Nicole Soranzo; Ida Surakka; Cecilia M. Lindgren; Jiannis Ragoussis; Andrew P. Morris; Lon R. Cardon; Tim D. Spector; Krina T. Zondervan

2011-01-01

313

77 FR 50144 - Broad Stakeholder Survey  

Federal Register 2010, 2011, 2012, 2013

...Docket No. DHS-2012-0042] Broad Stakeholder Survey AGENCY: National Protection...soliciting comments concerning the Broad Stakeholder Survey. DATES: Comments are encouraged...responders across the Nation. The Broad Stakeholder Survey is designed to gather...

2012-08-20

314

78 FR 20119 - Broad Stakeholder Survey  

Federal Register 2010, 2011, 2012, 2013

...Docket No. DHS-2012-0042] Broad Stakeholder Survey AGENCY: National Protection...soliciting comments concerning the Broad Stakeholder Survey. DHS previously published this...responders across the Nation. The Broad Stakeholder Survey is designed to gather...

2013-04-03

315

76 FR 34087 - Broad Stakeholder Survey  

Federal Register 2010, 2011, 2012, 2013

...Docket No. DHS-2011-0027] Broad Stakeholder Survey AGENCY: National Protection...soliciting comments concerning the Broad Stakeholder Survey. DATES: Comments are encouraged...responders across the Nation. The Broad Stakeholder Survey is designed to gather...

2011-06-10

316

Broad-Band Systems Standards  

Microsoft Academic Search

The broad-band communications industry is small and fractionated (about 3100 cable television systems serving 8.5 million subscribers in the U.S.), but has a high potential for growth by offering a wide variety of communications services. If this large number of systems is to collectively provide nationwide services, performance and interconnection standards will be essential. In this paper we note relevant

R. Powers

1975-01-01

317

Reorienting Our Perspective of Broad Absorption Line Quasars  

NASA Astrophysics Data System (ADS)

New multi-frequency radio observations of a large sample of radio-selected BAL quasars, along with a very well matched sample of normal quasars, are presented. The observations were made one immediately after the other at 4.9 and 8.4 GHz with the goal of measuring the radio spectral index of each source. We have identified, for the first time, a significant difference in the spectral index distributions of BAL versus non-BAL quasars, with BAL sources showing an overabundance of steep-spectrum sources. This is the first direct observation suggesting that BAL quasars are more likely to be seen farther from the radio jet axis, although a range of orientations is needed to explain the width of the distribution. Utilizing a few different relationships between spectral index and viewing angle, we have also performed Monte-Carlo simulations to quantify the viewing angle to these sources. We find that the difference in the distributions of spectral index can be explained by allowing the BAL sources to have viewing angles extending about 10 degrees farther from the jet axis than non-BAL quasars.

DiPompeo, M. A.; Brotherton, M. S.; De Breuck, C.; Laurent-Muehleisen, S.

2012-08-01

318

Broad-band power amplifier using dielectric photonic bandgap structure  

Microsoft Academic Search

Two class AB GaAs field-effect transistor (FET) power amplifiers have been designed and fabricated in the 4.4-4.8 GHz range. In the first case, a dielectric PBG line was incorporated in the design to tune the second harmonic. In the second case, a 50-? line is used with no harmonic tuning. The PBG structure allows broad-band harmonic tuning and is inexpensive

Vesna Radisic; Yongxi Qian; Tatsuo Itoh

1998-01-01

319

Priming with a very low dose of DNA complexed with cationic block copolymers followed by protein boost elicits broad and long-lasting antigen-specific humoral and cellular responses in mice.  

PubMed

Cationic block copolymers spontaneously assemble via electrostatic interactions with DNA molecules in aqueous solution giving rise to micellar structures that protect the DNA from enzymatic degradation both in vitro and in vivo. In addition, we have previously shown that they are safe, not immunogenic and greatly increased antigen-specific CTL responses following six intramuscular inoculations of a very low dose (1microg) of the vaccine DNA as compared to naked DNA. Nevertheless, they failed to elicit detectable humoral responses against the antigen. To gain further insight in the potential application of this technology, here we show that a shorter immunization protocol based on two DNA intramuscular inoculations of 1microg of DNA delivered by these copolymers and a protein boost elicits in mice broad (both humoral and cellular) and long-lasting responses and increases the antigen-specific Th1-type T cell responses and CTLs as compared to priming with naked DNA. These results indicate that cationic block copolymers represent a promising adjuvant and delivery technology for DNA vaccination strategies aimed at combating intracellular pathogens. PMID:19450649

Voltan, Rebecca; Castaldello, Arianna; Brocca-Cofano, Egidio; De Michele, Rita; Triulzi, Chiara; Altavilla, Giuseppe; Tondelli, Luisa; Laus, Michele; Sparnacci, Katia; Reali, Eva; Gavioli, Riccardo; Ensoli, Barbara; Caputo, Antonella

2009-05-28

320

[Analysis of storage proteins (prolamines, puroindolines and waxy) in common wheat lines Triticum aestivum L. x (Triticum timopheevii Zhuk. x Triticum tauschii) with complex resistance to fungal infections].  

PubMed

Storage proteins (prolamines, puroindolines, and Waxy) were studied in common wheat introgression lines obtained with the use of the Saratovskaya 29 (S29) cultivar line and synthetic hexaploid wheat (Triticum timopheevii Zhuk. x T. tauschii) (Sintetik, Sin.) and displaying complex resistance to fungal infections. Comparative analysis of storage proteins in the introgression lines of common wheat Triticum aestivum L. and in the parental forms revealed the only line (BC5) having a substitution at the Gli-B2 locus from Sintetik. Hybrid lines subjected to nine back crosses with the recurrent parental form S29 and selections for resistance to pathogens can be considered as nearly isogenic for the selected trait and retaining the allelic composition of (1) prolamines responsible for the bread-making qualitiy, (2) puroindolines associated with grain texture, and (3) Waxy proteins responsible for nutritive qualities. These lines are valuable as donors of immunity in breeding programs without the loss of the quality of flour and grain as compared to the S29 line and are also important in searching for genes determining resistance to leaf and stem rust and to powdery mildew. The amphiploid has a number of characters (silent Glu-A 1 locus and Ha genotype) that can negatively affect the quality of flour and grain and thus should be taken into account when choosing this donor. PMID:20734767

Obukhova, L V; La?kova, L I; Shumny?, V K

2010-06-01

321

Broad-Spectrum Antiviral Therapeutics  

PubMed Central

Currently there are relatively few antiviral therapeutics, and most which do exist are highly pathogen-specific or have other disadvantages. We have developed a new broad-spectrum antiviral approach, dubbed Double-stranded RNA (dsRNA) Activated Caspase Oligomerizer (DRACO) that selectively induces apoptosis in cells containing viral dsRNA, rapidly killing infected cells without harming uninfected cells. We have created DRACOs and shown that they are nontoxic in 11 mammalian cell types and effective against 15 different viruses, including dengue flavivirus, Amapari and Tacaribe arenaviruses, Guama bunyavirus, and H1N1 influenza. We have also demonstrated that DRACOs can rescue mice challenged with H1N1 influenza. DRACOs have the potential to be effective therapeutics or prophylactics for numerous clinical and priority viruses, due to the broad-spectrum sensitivity of the dsRNA detection domain, the potent activity of the apoptosis induction domain, and the novel direct linkage between the two which viruses have never encountered.

Rider, Todd H.; Zook, Christina E.; Boettcher, Tara L.; Wick, Scott T.; Pancoast, Jennifer S.; Zusman, Benjamin D.

2011-01-01

322

Broad-spectrum antiviral therapeutics.  

PubMed

Currently there are relatively few antiviral therapeutics, and most which do exist are highly pathogen-specific or have other disadvantages. We have developed a new broad-spectrum antiviral approach, dubbed Double-stranded RNA (dsRNA) Activated Caspase Oligomerizer (DRACO) that selectively induces apoptosis in cells containing viral dsRNA, rapidly killing infected cells without harming uninfected cells. We have created DRACOs and shown that they are nontoxic in 11 mammalian cell types and effective against 15 different viruses, including dengue flavivirus, Amapari and Tacaribe arenaviruses, Guama bunyavirus, and H1N1 influenza. We have also demonstrated that DRACOs can rescue mice challenged with H1N1 influenza. DRACOs have the potential to be effective therapeutics or prophylactics for numerous clinical and priority viruses, due to the broad-spectrum sensitivity of the dsRNA detection domain, the potent activity of the apoptosis induction domain, and the novel direct linkage between the two which viruses have never encountered. PMID:21818340

Rider, Todd H; Zook, Christina E; Boettcher, Tara L; Wick, Scott T; Pancoast, Jennifer S; Zusman, Benjamin D

2011-07-27

323

Narrow complex (supraventricular) tachycardias  

Microsoft Academic Search

Patients experiencing a narrow complex tachycardia are usually at a lower risk than those in whom a broad complex tachycardia occurs. Therefore, in the UK cardiologists are frequently involved in broad complex dysrhythmias at an early stage, while general physicians and general practitioners will often have greater involvement in the management of patients with narrow complex arrhythmias. We describe the

N W F Linton; S W Dubrey

2009-01-01

324

AGS broad band neutrino beam  

SciTech Connect

We describe the broad band neutrino beam in the north area of the AGS and discuss the calculation of the neutrino flux. The horns were initially designed by Robert Palmer and this beam has been used for almost all neutrino running at the AGS. All of the wide band running for E734 has been done in the beam we discuss. E734 is an experiment designed to measure elastic scattering of neutrinos and antineutrinos on electrons and protons. The detector is sufficiently large (approx. =170 tons) that enough events can be detected to make precision measurements of cross sections. In particular, the reaction nu/sub ..mu../ + e ..-->.. nu/sub ..mu../ + e has been detected with more than 100 events, requiring a detailed understanding of the beam characteristics for normalization.

White, D.H.

1985-02-27

325

Induction of apoptotic cell death in mouse lymphoma and human leukemia cell lines by a calcium-binding protein complex, calprotectin, derived from inflammatory peritoneal exudate cells  

Microsoft Academic Search

We have previously shown that the cal- cium-binding protein complex, caiprotectin, purified from rat inflammatory peritoneal cells exerts marked cytotoxic activity against rat, mouse, and human tumor cells. We studied here whether the cytotoxicity is caused by induction of apoptosis, using mouse EL-4 lymphoma and human MOLT-4 leukemia lines as targets. The rat caiprotectin sample inhibited (3H)thymidine incorporation into these

Satoru Yui; Masaaki Mikami; Masatoshi Yamazaki

326

Mycobacterium riyadhense sp. nov., a non-tuberculous species identified as Mycobacterium tuberculosis complex by a commercial line-probe assay  

Microsoft Academic Search

A non-chromogenic, slowly growing Mycobacterium strain was isolated from a maxillary sinus lavage from a symptomatic patient in Riyadh, Saudi Arabia. It was initially identified as a member of the Mycobacterium tuberculosis complex by a commercial line-probe assay. Its 16S rRNA, hsp65 and rpoB gene and 16S-23S internal transcribed spacer sequences were unique; phylogenetic analysis based on the 16S rRNA

J. van Ingen; S. A. M. Al-Hajoj; M. J. Boeree; F. Al-Rabiah; M. Enaimi; R. de Zwaan; E. Tortoli; R. Dekhuijzen; D. van Soolingen

2009-01-01

327

Synthesis and characterization of new palladium-clotrimazole and palladium-chloroquine complexes showing cytotoxicity for tumor cell lines in vitro.  

PubMed

New palladium complexes of chloroquine (CQ) and clotrimazole (CTZ) have been prepared, characterized, and evaluated against four tumor cell lines in vitro. [Pd (CQ)2Cl2] (1) was synthesized by the reaction of PdCl2(CH3CN)2 with CQ, and the [Pd (CTZ)2Cl2] (2) complex by a similar reaction. The new compounds were characterized by a combination of FAB-MS (fast atom bombardment-mass spectrum), elemental analysis, molar conductivity, IR, and NMR spectroscopy. The solid-state structure of 2 has been determined by X-ray crystallography. 2 crystallizes in the monoclinic space group P(2(1)/c), with a = 21.100(4) A, b = 13.408(3) A, c = 22.642(5) A. The structure refinement converged at R1 = 0.0728, wR2 = 0.1918. The cytotoxicity of these two complexes for the tumor cell lines, PANC-1, SKBR-3, MDA-MB231 and HT-29, was compared with that of the original ligands. Ligation of palladium to CTZ led to an increase in the IC50, although a three-fold reduction in the IC50 of CQ was observed on ligation to the metal when tested against the MDA-MB231 cell line. PMID:16343632

Navarro, Maribel; Peña, Nayarit Prieto; Colmenares, Ibis; González, Teresa; Arsenak, Miriam; Taylor, Peter

2005-12-15

328

The search for complex molecules in the ISM: a complete 3mm line survey of Sgr B2-N and -M  

NASA Astrophysics Data System (ADS)

Famous for the extraordinary richness of its molecular content, the Sgr B2 molecular cloud complex is the prime target in the long-standing search for ever more complex species. We have completed a molecular line survey of the hot dense cores Sgr B2(N) and SgrB2(M) in the 3 mm wavelength range with the IRAM 30m telescope. We performed the analysis of this huge data set by modeling the whole spectrum at once in the LTE approximation. Ongoing analyses yield an average line density of about 100 features/GHz above 3sigma for Sgr B2(N), emitted and/or absorbed by a total of 51 molecular species. We find lines from 60 rare isotopologues and from 41 vibrationally excited states in addition to the main species, vibrational ground state lines. For Sgr B2(M), we find about 25 features/GHz above 3sigma, from 41 molecular species plus 50 isotopologues and 20 vibrationally excited states. Thanks to the constant updates to the Cologne Database for Molecular Spectroscopy, we are working our way through the assignment of the unidentified features, currently 40% and 50% above 3sigma for Sgr B2(N) and SgrB2(M), respectively.

Belloche, A.; Comito, C.; Hieret, C.; Menten, K. M.; Müller, H. S. P.; Schilke, P.

2007-12-01

329

Structure of a Novel Shoulder-to-Shoulder p24 Dimer in Complex with the Broad-Spectrum Antibody A10F9 and Its Implication in Capsid Assembly  

PubMed Central

Mature HIV-1 viral particles assemble as a fullerene configuration comprising p24 capsid hexamers, pentamers and dimers. In this paper, we report the X-ray crystal structures of the p24 protein from natural HIV-1 strain (BMJ4) in complex with Fab A10F9, which recognizes a conserved epitope in the C-terminal domain of the BMJ4 p24 protein. Our structures reveal a novel shoulder-to-shoulder p24 dimerization mode that is mediated by an S-S bridge at C177. Consistent with these structures, the shoulder-to-shoulder dimer that was obtained from the BMJ4 strain was also observed in p24 proteins from other strains by the introduction of a cysteine residue at position 177. The potential biological significance was further validated by the introduction of a C177A mutation in the BMJ4 strain, which then displays a low infectivity. Our data suggest that this novel shoulder-to-shoulder dimer interface trapped by this unique S-S bridge could represent a physiologically relevant mode of HIV-1 capsid assembly during virus maturation, although Cys residue itself may not be critical for HIV-I replication.

Gu, Ying; Cao, Fang; Wang, Lei; Hou, Wangheng; Zhang, Jun; Hew, Choy-leong; Li, Shaowei; Yuan, Y. Adam; Xia, Ningshao

2013-01-01

330

TYPE 2 ACTIVE GALACTIC NUCLEI WITH DOUBLE-PEAKED [O III] LINES. II. SINGLE AGNs WITH COMPLEX NARROW-LINE REGION KINEMATICS ARE MORE COMMON THAN BINARY AGNs  

SciTech Connect

Approximately 1% of low-redshift (z {approx}< 0.3) optically selected type 2 active galactic nuclei (AGNs) show a double-peaked [O III] narrow emission line profile in their spatially integrated spectra. Such features are usually interpreted as either due to kinematics, such as biconical outflows and/or disk rotation of the narrow line region (NLR) around single black holes, or due to the relative motion of two distinct NLRs in a merging pair of AGNs. Here, we report follow-up near-infrared (NIR) imaging and optical slit spectroscopy of 31 double-peaked [O III] type 2 AGNs drawn from the Sloan Digital Sky Survey (SDSS) parent sample presented in Liu et al. The NIR imaging traces the old stellar population in each galaxy, while the optical slit spectroscopy traces the NLR gas. These data reveal a mixture of origins for the double-peaked feature. Roughly 10% of our objects are best explained by binary AGNs at (projected) kpc-scale separations, where two stellar components with spatially coincident NLRs are seen. {approx}50% of our objects have [O III] emission offset by a few kpc, corresponding to the two velocity components seen in the SDSS spectra, but there are no spatially coincident double stellar components seen in the NIR imaging. For those objects with sufficiently high-quality slit spectra, we see velocity and/or velocity dispersion gradients in [O III] emission, suggestive of the kinematic signatures of a single NLR. The remaining {approx}40% of our objects are ambiguous and will need higher spatial resolution observations to distinguish between the two scenarios. Our observations therefore favor the kinematics scenario with a single AGN for the majority of these double-peaked [O III] type 2 AGNs. We emphasize the importance of combining imaging and slit spectroscopy in identifying kpc-scale binary AGNs, i.e., in no cases does one of these alone allow an unambiguous identification. We estimate that {approx}0.5%-2.5% of the z {approx}< 0.3 type 2 AGNs are kpc-scale binary AGNs of comparable luminosities, with a relative orbital velocity {approx}> 150 km s{sup -1}.

Shen Yue; Liu Xin [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51, Cambridge, MA 02138 (United States); Greene, Jenny E. [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Strauss, Michael A. [Princeton University Observatory, Princeton, NJ 08544 (United States)

2011-07-01

331

Broad-spectrum blockade,* proven cardioprotection  

Center for Drug Evaluation (CDER)

Text Version... CRG905R0A Broad-spectrum blockade,* proven cardioprotection ... N Engl J Med. 2001;344:1651-1658. COREG provides broad-spectrum blockade, ... More results from www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation

332

Study of peptide on-line complexation with transition-metal ions generated from sacrificial electrodes in thin-chip polymer microsprays.  

PubMed

A miniaturized polymer electrospray-type interface is used to study metal-ion chelation with model peptides. Taking advantage of the intrinsic electrochemical behavior of electrospray, a sacrificial electrode is used to generate at the same time electrospray and transition-metal ions coming from the anodic dissolution of the electrode. The microspray interface provides enhanced mass transport due to its small dimensions, increasing the yield of possible reactions, in particular complex formation. Transition-metal electrodes, e.g. copper, zinc, nickel, iron and silver, are used to obtain on-line complexation with model peptides. It is demonstrated that the use of in-reservoir sacrificial electrodes is an efficient way to generate metal ions in order to form and study complexes with peptides, avoiding the addition of metallic salts. PMID:15818723

Rohner, Tatiana C; Girault, Hubert H

2005-01-01

333

On-line concentration of neutral analytes by complexation and acetonitrile sweeping in nonionic microemulsion electrokinetic chromatography with direct ultraviolet detection.  

PubMed

To separate and detect neutral solutes in nonionic microemulsion electrokinetic chromatography (MEEKC), a novel method was developed, combining complex formation and acetonitrile (ACN) sweeping. In this report, dynamic borate complexation and on-line sweeping occurred simultaneously during a run. The operating parameters which affected the performance of analyte sweeping in nonionic MEEKC were examined in terms of borate complexation, ACN content, Brij-35 concentration and sample plug length. In addition, the validation of the method included tests of the limit of detection, reproducibility and sensitivity enhancement. 60-110-Fold of magnitude improvement in detection sensitivity for model compounds (ginsenoside Rf, ginsenoside Rb2, ginsenoside Re) using Brij-35 microemulsion was demonstrated. Furthermore, the method was applied to the determination of glucosides in the plant extract. PMID:19524933

Cao, Jun; Yi, Ling; Li, Ping; Chang, Yan-Xu

2009-06-03

334

Characterization of the Androgen-sensitive MDA-kb2 Cell Line for Assessing Complex Environmental Mixtures  

EPA Science Inventory

Complex mixtures of synthetic and natural androgens and estrogens, and many other non-steroidal components are commonly released to the aquatic environment from anthropogenic sources. It is important to understand the potential interactive (i.e., additive, synergistic, antagonist...

335

Biochemical properties and mechanism of action of a vanadyl(IV) – aspirin complex on bone cell lines in culture  

Microsoft Academic Search

A recently synthesized vanadyl(IV) complex with aspirin[VO(aspirin)ClH2O]2, has been thoroughly investigated by physicochemical techniques. In order to support the proposed structure, stoichiometry and the coordination sphere of the vanadium center, some studies such as elemental analysis, electronic (diffuse reflectance) and vibrational (infrared) spectroscopies, magnetic susceptibility, as well as the thermal behavior, were carried out. The bioactivity of the vanadium complex

Susana B. Etcheverry; Patricia A. M. Williams; Viviana C. Sálice; Daniel A. Barrio; Evelina G. Ferrer; Ana M. Cortizo

2002-01-01

336

Bead-probe complex capture a couple of SINE and LINE family from genomes of two closely related species of East Asian cyprinid directly using magnetic separation  

PubMed Central

Background Short and long interspersed elements (SINEs and LINEs, respectively), two types of retroposons, are active in shaping the architecture of genomes and powerful tools for studies of phylogeny and population biology. Here we developed special protocol to apply biotin-streptavidin bead system into isolation of interspersed repeated sequences rapidly and efficiently, in which SINEs and LINEs were captured directly from digested genomic DNA by hybridization to bead-probe complex in solution instead of traditional strategy including genomic library construction and screening. Results A new couple of SINEs and LINEs that shared an almost identical 3'tail was isolated and characterized in silver carp and bighead carp of two closely related species. These SINEs (34 members), designated HAmo SINE family, were little divergent in sequence and flanked by obvious TSD indicated that HAmo SINE was very young family. The copy numbers of this family was estimated to 2 × 105 and 1.7 × 105 per haploid genome by Real-Time qPCR, respectively. The LINEs, identified as the homologs of LINE2 in other fishes, had a conserved primary sequence and secondary structures of the 3'tail region that was almost identical to that of HAmo SINE. These evidences suggest that HAmo SINEs are active and amplified recently utilizing the enzymatic machinery for retroposition of HAmoL2 through the recognition of higher-order structures of the conserved 42-tail region. We analyzed the possible structures of HAmo SINE that lead to successful amplification in genome and then deduced that HAmo SINE, SmaI SINE and FokI SINE that were similar in sequence each other, were probably generated independently and created by LINE family within the same lineage of a LINE phylogeny in the genomes of different hosts. Conclusion The presented results show the advantage of the novel method for retroposons isolation and a pair of young SINE family and its partner LINE family in two carp fishes, which strengthened the hypotheses containing the slippage model for initiation of reverse transcription, retropositional parasitism of SINEs on LINEs, the formation of the stem loop structure in 3'tail region of some SINEs and LINEs and the mechanism of template switching in generating new SINE family.

Tong, Chaobo; Guo, Baocheng; He, Shunping

2009-01-01

337

Five-lipoxygenase inhibitors can mediate apoptosis in human breast cancer cell lines through complex eicosanoid interactions  

Microsoft Academic Search

Many arachidonic acid metabolites function in growth signaling for epithelial cells, and we previously reported the expression of the major arachidonic acid enzymes in human breast cancer cell lines. To evaluate the role of the 5-lipoxygenase (5-LO) pathway on breast cancer growth regulation, we exposed cells to insulinlike growth factor-1 or transferrin, which increased the levels of the 5-LO metabolite,

Ingalill Avis; Sung H. Hong; Alfredo Martínez; Terry Moody; Yung H. Choi; Jane Trepel; Rina Das; Marti Jett; James L. Mulshine

2001-01-01

338

Dermatitis and systemic mycosis in lined seahorses Hippocampus erectus associated with a marine-adapted Fusarium solani species complex pathogen  

Technology Transfer Automated Retrieval System (TEKTRAN)

During a 4 month epizootic, 100% of 152 lined seahorses Hippocampus erectus in three separate groups died while in quarantine following shipment to a public aquarium. Twelve animals with skin depigmentation and ulceration were received by the Aquatic Pathology Service, University of Georgia, College...

339

Uniplanar broad-band push-pull FET amplifiers  

Microsoft Academic Search

We report the development of completely uniplanar broadband balanced push-pull FET amplifiers using slot line and coplanar waveguide. The amplifiers employ broad-band uniplanar baluns to achieve the push-pull function over a wide bandwidth. One amplifier, designed in the unconditionally stable region, exhibits a gain of 3.5-5 dB over the frequency range of 5.4-10 GHz and an output 1-dB compression point

P.-C. Hsu; C. Nguyen; M. Kintis

1997-01-01

340

Calculating statistics of complex networks through random walks with an application to the on-line social network Bebo  

NASA Astrophysics Data System (ADS)

We develop a methodology with which to calculate typical network statistics by sampling a network through a random walk. By examining the statistics of degree and return times of walks which return to the same vertex, we can estimate characteristics of the giant component such as average clustering coefficient, degree distribution, degree correlations and network size. We confirm the validity of the methods using a variety of available network network data sets and then apply these methods to data collected by performing a random walk on the large on-line social networking website, Bebo. We find good agreement between our results and the results of previous studies of on-line social networks in which data collection was performed by a BFS (“snow-ball”) sampling algorithm. In particular, we find that the degree distribution exhibits a multi-scaling power-law tail and the network exhibits clustering and positive degree correlations. in here

Hardiman, S. J.; Richmond, P.; Hutzler, S.

2009-10-01

341

On the importance of satellite lines to the He-like alpha complex and the G ration for calcium, iron, and nickel  

SciTech Connect

New, more detailed calculations of the emission spectra of the He-like Ko complex of calcium, iron and nickel have been carried out using data from both distorted-wave and R-matrix calculations. The value of the GD ratio (a corrected version of the G ratio that accounts for the effect of unresolved satellite lines) is significantly enhanced at temperatures below the temperature of He-like maximum abundance. Furthermore it is shown that satellite lines are important contributors to the G D ratio at temperatures well above the temperature of maximum abundance. These new calculations demonstrate that satellite lines need to be included in models of He-like Ko spectra even at relatively high temperatures. The excellent agreement between spectra and line ratios calculated from R-matrix and distorted-wave data also confirms the validity of models based on distorted-wave data for highly charged systems, provided the effect of resonances are taken into account as independent processes.

Oelgoetz, Justin R [Los Alamos National Laboratory; Fontes, Christopher J [Los Alamos National Laboratory; Zhang, Hong L [Los Alamos National Laboratory; Nahar, Sultana N [OHIO STATE UNIV; Pradhan, Anil K [OHIO STATE UNIV

2008-01-01

342

33 CFR 110.27 - Lynn Harbor in Broad Sound, Mass.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Lynn Harbor in Broad Sound, Mass. 110.27 Section 110.27 Navigation and Navigable Waters...Special Anchorage Areas § 110.27 Lynn Harbor in Broad Sound, Mass. North of a line bearing 244° from the tower of...

2013-07-01

343

Characterization of the Androgen-sensitive MDA-kb2 Cell Line for Assessing Complex Environmental Mixtures, Presentation  

EPA Science Inventory

Synthetic and natural steroidal androgens and estrogens and many other non-steroidal endocrine-active compounds commonly occur as complex mixtures in aquatic environments. It is important to understand the potential interactive effects of these mixtures to properly assess their r...

344

Flow-injection in-line complexation for ion-pair reversed phase high performance liquid chromatography of some metal-4-(2-pyridylazo) resorcinol chelates  

Microsoft Academic Search

Flow injection (FI) was coupled to ion-pair reversed phase high performance liquid chromatography (IP-RPHPLC) for the simultaneous analysis of some metal-4-(2-pyridylazo) resorcinol (PAR) chelates. A simple reverse flow injection (rFI) set-up was used for in-line complexation of metal-PAR chelates prior to their separation by IP-RPHPLC. The rFI conditions were: injection volume of PAR 85?L, flow rate of metal stream 4.5mLmin?1,

Supalax Srijaranai; Saiphon Chanpaka; Chutima Kukusamude; Kate Grudpan

2006-01-01

345

Two fast methods for high-quality line visibility.  

PubMed

Lines drawn over or in place of shaded 3D models can often provide greater comprehensibility and stylistic freedom than shading alone. A substantial challenge for making stylized line drawings from 3D models is the visibility computation. Current algorithms for computing line visibility in models of moderate complexity are either too slow for interactive rendering, or too brittle for coherent animation. We introduce two methods that exploit graphics hardware to provide fast and robust line visibility. First, we present a simple shader that performs a visibility test for high-quality, simple lines drawn with the conventional implementation. Next, we offer a full optimized pipeline that supports line visibility and a broad range of stylization options. PMID:20616387

Cole, Forrester; Finkelstein, Adam

346

The IRAM-30 m line survey of the Horsehead PDR. III. High abundance of complex (iso-)nitrile molecules in UV-illuminated gas  

NASA Astrophysics Data System (ADS)

Context. Complex (iso-)nitrile molecules, such as CH3CN and HC3N, are relatively easily detected in our Galaxy and in other galaxies. Aims: We aim at constraining their chemistry through observations of two positions in the Horsehead edge: the photo-dissociation region (PDR) and the dense, cold, and UV-shielded core just behind it. Methods: We systematically searched for lines of CH3CN, HC3N, C3N, and some of their isomers in our sensitive unbiased line survey at 3, 2, and 1 mm. We stacked the lines of C3N to improve the detectability of this species. We derived column densities and abundances through Bayesian analysis using a large velocity gradient radiative transfer model. Results: We report the first clear detection of CH3NC at millimeter wavelength. We detected 17 lines of CH3CN at the PDR and 6 at the dense core position, and we resolved its hyperfine structure for 3 lines. We detected 4 lines of HC3N, and C3N is clearly detected at the PDR position. We computed new electron collisional rate coefficients for CH3CN, andwe found that including electron excitation reduces the derived column density by 40% at the PDR position, where the electron density is 1-5 cm-3. While CH3CN is 30 times more abundant in the PDR (2.5 × 10-10) than in the dense core (8 × 10-12), HC3N has similar abundance at both positions (8 × 10-12). The isomeric ratio CH3NC/CH3CN is 0.15 ± 0.02. Conclusions: The significant amount of complex (iso-)nitrile molecule in the UV illuminated gas is puzzling as the photodissociation is expected to be efficient. This is all the more surprising in the case of CH3CN, which is 30 times more abundant in the PDR than in the dense core. In this case, pure gas phase chemistry cannot reproduce the amount of CH3CN observed in the UV-illuminated gas. We propose that CH3CN gas phase abundance is enhanced when ice mantles of grains are destroyed through photo-desorption or thermal-evaporation in PDRs, and through sputtering in shocks. Based on observations obtained with the IRAM-30 m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).Appendices are available in electronic form at http://www.aanda.org

Gratier, P.; Pety, J.; Guzmán, V.; Gerin, M.; Goicoechea, J. R.; Roueff, E.; Faure, A.

2013-09-01

347

Magnetic Flux Lines in Complex Geometry Type-II Superconductors Studied by the Time Dependent Ginzburg-Landau Equation  

Microsoft Academic Search

The time-dependent Ginzburg-Landau equation is solved numerically for type-II superconductors of complex geometry using the\\u000a finite element method. The geometry has a marked influence on the magnetic vortex distribution and the vortex dynamics. We\\u000a have observed generation of giant vortices at boundary defects, suppressing the superconducting state far into the superconductor.

Tommy Sonne Alstrøm; Mads Peter Sørensen; Niels Falsig Pedersen; Søren Madsen

2011-01-01

348

A High-metallicity, High-velocity Cloud Along the Mrk 421 Sight Line: A Tracer of Complex M?  

Microsoft Academic Search

We present a new measurement, 0.85-3.5 Z sun, of the metallicity of high-velocity cloud (HVC) Complex M by analyzing ultraviolet spectroscopic observations of the blazar Mrk 421 taken with the Cosmic Origins Spectrograph on the Hubble Space Telescope and the Far-Ultraviolet Spectroscopic Explorer. Although an HVC at V LSR = -131 km s-1 is not visible in 21 cm emission

Yangsen Yao; J. Michael Shull; Charles W. Danforth

2011-01-01

349

Immune response to a killed infectious bursal disease virus vaccine in inbred chicken lines with different major histocompatibility complex haplotypes.  

PubMed

The influence of MHC on antibody responses to killed infectious bursal disease virus (IBDV) vaccine was investigated in several MHC inbred chicken lines. We found a notable MHC haplotype effect on the specific antibody response against IBDV as measured by ELISA. Some MHC haplotypes were high responders (B201, B4, and BR5), whereas other MHC haplotypes were low responders (B19, B12 and BW3). The humoral response of 1 pair of recombinants isolated from a Red Jungle Fowl (BW3 and BW4) being identical on BF and BG, but different on BL, indicated that part of the primary vaccine response was an MHC II restricted T-cell dependent response. The humoral response in another pair of recombinant haplotypes originating in 2 different White Leghorn chickens being BF21, BL21, BG15 (BR4) and BF15, BL15, BG21 (BR5) on the MHC locus indicated that the BG locus may perform an adjuvant effect on the antibody response as well. Vaccination of chickens at different ages and in lines with different origin indicated that age and background genes also influence the specific antibody response against inactivated IBDV vaccine. PMID:16776466

Juul-Madsen, H R; Dalgaard, T S; Røntved, C M; Jensen, K H; Bumstead, N

2006-06-01

350

On-line preparation of peroxymonocarbonate and its application for the study of energy transfer chemiluminescence to lanthanide inorganic coordinate complexes.  

PubMed

It has been shown that peroxymonocarbonate ion (HCO(4) (-)) is a potent oxidant. In this study, a flow-injection system was developed in order to prepare on-line HCO(4) (-) ion and the optimum conditions for the on-line preparation of HCO(4) (-) were studied in detail. We used 99% (13)C-enriched NaHCO(3) to examine peroxymonocarbonate by (13)C-NMR at 25 degrees C. An ultra-weak chemiluminescence (CL) was observed after mixing H(2)O(2) and sodium bicarbonate in an organic co-solvent that can accelerate the formation of HCO(4) (-) ion. When lanthanide inorganic coordinate complex, Eu(II)-EDTA, was added into this HCO(4) (-) system, the CL intensity was significantly enhanced. The CL mechanism was investigated by various methods. The experimental results indicate that peroxymonocarbonate oxidizes Eu(II) to Eu(III) and produces singlet oxygen; meanwhile, the energy originating from dimers of singlet oxygen is accepted by the Eu(III)-EDTA(-) complex. The excited Eu(III) ions undergo radiative deactivation and emit CL. PMID:16645954

Liu, Meilin; Cheng, Xianglei; Zhao, Lixia; Lin, Jin-Ming

351

Land-atmosphere interactions over complex terrain in South America and the impact of tree line shifts  

NASA Astrophysics Data System (ADS)

The diurnal cycle of land-atmosphere interactions in South America was investigated using the Weather Research and Forecasting (WRF-ARW3.2.1) model and mixing diagrams. Model simulations show that, as an elevated heating source and a physical barrier, the Andes can induce cold and moist entrainment at the top of the atmospheric boundary layer (ABL). Subsequently, the impact of tree line shifts between 500 and 1,500 m elevation, similar to what may be expected under a changing climate, was examined for three different cases: weak and strong Low Level Jet (LLJ) conditions during the monsoon season; and a rainless case during the dry season. Over eastern Brazil, dry entrainment at the top of the ABL dominates the water budget in the boundary layer in the dry season case-study. After tree line shifts, its influence is reduced, though still dominant, leading to a relatively moist ABL and thus a lower lifting condensation level (LCL). In contrast, systematic changes of LCL were not found over this area for the wet season experiments, during which entrainment is not dominant. Along the eastern slope of the Andes, the South American LLJ (SALLJ) is the major contributor to the water balance in the ABL. Consequently, the impact of tree line shifts is not significant in either dry or wet conditions. On the other hand, the distance between the LCL and the level of free convection (LFC), which is proportional to convective inhibition (CIN), increases over the eastern Brazil, indicating more stress (less precipitation) to the degraded vegetation, and a positive feedback. Because the characteristics of the SALLJ are directly associated with the Amazon basin, simulations with deforestation in the adjacent low lands were conducted to understand their impact on cloud formation over the high Andes region. Analysis of large-scale conditions as well as moisture transport patterns was also conducted to characterize the physical processes responsible for the spatial heterogeneity of land-atmosphere interactions in South America. Discrepancies between the result presented herein and previous work are examined in detail, and physical interpretations are proposed.

Sun, X.; Barros, A. P.

2011-12-01

352

Multipotent adult germ-line stem cells, like other pluripotent stem cells, can be killed by cytotoxic T lymphocytes despite low expression of major histocompatibility complex class I molecules  

Microsoft Academic Search

BACKGROUND: Multipotent adult germ-line stem cells (maGSCs) represent a new pluripotent cell type that can be derived without genetic manipulation from spermatogonial stem cells (SSCs) present in adult testis. Similarly to induced pluripotent stem cells (iPSCs), they could provide a source of cellular grafts for new transplantation therapies of a broad variety of diseases. To test whether these stem cells

Ralf Dressel; Kaomei Guan; Jessica Nolte; Leslie Elsner; Sebastian Monecke; Karim Nayernia; Gerd Hasenfuss; Wolfgang Engel

2009-01-01

353

A High-Metallicity High Velocity Cloud along the MRK 421 Sight Line: A Tracer of Complex M?  

Microsoft Academic Search

We present a new measurement, 0.85-3.5 Z_solar, of the metallicity of high\\u000avelocity cloud (HVC) Complex M by analyzing ultraviolet spectroscopic\\u000aobservations of the blazar Mrk 421 taken with the Cosmic Origins Spectrograph\\u000aon the Hubble Space Telescope and the Far Ultraviolet Spectroscopic Explorer.\\u000aAlthough an HVC at V_LSR = -131 km\\/s is not visible in 21 cm emission\\u000a(logN_HI<18.38;

Yangsen Yao; J. Michael Shull; Charles W. Danforth

2011-01-01

354

Broad Prize: Do the Successes Spread?  

ERIC Educational Resources Information Center

|When the Broad Prize for Urban Education was created in 2002, billionaire philanthropist Eli Broad said he hoped the awards, in addition to rewarding high-performing school districts, would foster healthy competition; boost the prestige of urban education, long viewed as dysfunctional; and showcase best practices. Over the 10 years the prize has…

Samuels, Christina A.

2011-01-01

355

MiR-21 is enriched in the RNA-induced silencing complex and targets COL4A1 in human granulosa cell lines.  

PubMed

MicroRNAs (miRNAs) are noncoding small RNAs that play important roles in a variety of physiological and pathological events. In this study, we performed large-scale profiling of EIF2C2-bound miRNAs in 3 human granulosa-derived cell lines (ie, KGN, HSOGT, and GC1a) by high-throughput sequencing and found that miR-21 accounted for more than 80% of EIF2C2-bound miRNAs, suggesting that it was enriched in the RNA-induced silencing complex (RISC) and played a functional role in human granulosa cell (GC) lines. We also found high expression levels of miR-21 in primary human GCs. Assuming that miR-21 target mRNAs are enriched in RISC, we performed cDNA cloning of EIF2C2-bound mRNAs in KGN cells. We identified COL4A1 mRNA as a miR-21 target in the GC lines. These data suggest that miR-21 is involved in the regulation of the synthesis of COL4A1, a component of the basement membrane surrounding the GC layer and granulosa-embedded extracellular structure. PMID:22573493

Mase, Yuri; Ishibashi, Osamu; Ishikawa, Tomoko; Takizawa, Takami; Kiguchi, Kazushige; Ohba, Takashi; Katabuchi, Hidetaka; Takeshita, Toshiyuki; Takizawa, Toshihiro

2012-05-09

356

The cdk1-cyclin B complex is involved in everolimus triggered resistance in the PC3 prostate cancer cell line.  

PubMed

The growth potential of PC3 prostate cancer cells, sensible (PC3(par)) or resistant (PC3(res)) to the mTOR inhibitor everolimus (RAD001) was investigated. Cell growth and proliferation of PC3(res) was similar to that of PC3(par), and late apoptosis increased in PC3(par) but decreased in PC3(res) following treatment with low dosed everolimus. PC3(res) accumulated in the G2/M-phase, accompanied by cdk1, cdk2 and cyclin B elevation. Knocking down cdk1 or cyclin B distinctly blocked the growth activity of PC3(res). One reason for everolimus resistance may be up-regulation of the cdk1-cyclin B complex in prostate cancer cells, leading to enhanced progression towards G2/M. PMID:21925791

Tsaur, Igor; Makarevi?, Jasmina; Hudak, Lukasz; Juengel, Eva; Kurosch, Martin; Wiesner, Christoph; Bartsch, Georg; Harder, Sebastian; Haferkamp, Axel; Blaheta, Roman A

2011-09-03

357

The changing base line of complex ventricular arrhythmias. A new consideration in assessing long-term antiarrhythmic drug therapy.  

PubMed

Initial base-line electrocardiograms are used to assess the efficacy of treatment for ventricular arrhythmias. This approach assumes that in the absence of treatment the frequency of arrhythmia would remain constant. To test the validity of this assumption, we studied 26 clinically stable patients with symptomatic but not life-threatening ventricular arrhythmias, during two periods of placebo treatment separated by a mean of 17 months. As compared with the initial placebo period, there were significant reductions in ventricular premature depolarizations (50 per cent), pairs (65 per cent), and ventricular tachycardia (83 per cent) during the second period of placebo administration (P less than or equal to 0.05 for all comparisons). Over one third of the patients gave the appearance of receiving successful therapy during the second placebo period, even when the reported spontaneous variability of ventricular arrhythmia was taken into consideration. If unrecognized, these long-term spontaneous changes in the frequency of arrhythmia could result in continuation of unnecessary and potentially toxic therapy and lead to incorrect conclusions regarding the efficacy of antiarrhythmic drugs in clinical trials. We therefore recommend that the frequency of arrhythmia be reassessed annually in the absence of treatment in patients similar to those in our study. These recommendations should not be applied to patients with life-threatening ventricular arrhythmias. PMID:3903506

Pratt, C M; Delclos, G; Wierman, A M; Mahler, S A; Seals, A A; Leon, C A; Young, J B; Quinones, M A; Roberts, R

1985-12-01

358

Chemical Complexity in the Helix Nebula: Multi-line Observations of H2CO, HCO+, and CO  

NASA Astrophysics Data System (ADS)

Observations of CO, HCO+, and H2CO have been carried out at nine positions across the Helix Nebula (NGC 7293) using the Submillimeter Telescope and the 12 m antenna of the Arizona Radio Observatory. Measurements of the J = 1 ? 0, 2 ? 1, and 3 ?2 transitions of CO, two transitions of HCO+ (J = 1 ? 0 and 3 ?2), and five lines of H2CO (J Ka, Kc = 10, 1 ? 00, 0, 21, 2 ? 11, 1, 20, 2 ? 10, 1, 21, 1 ? 11, 0, and 30, 3 ?20, 2) were conducted in the 0.8, 1, 2, and 3 mm bands toward this highly evolved planetary nebula. HCO+ and H2CO were detected at all positions, along with three transitions of CO. From a radiative transfer analysis, the kinetic temperature was found to be T K ~ 15-40 K across the Helix with a gas density of n(H2) ~ 0.1-5 × 105 cm-3. The warmer gas appears to be closer to the central star, but high density material is distributed throughout the nebula. For CO, the column density was found to be N tot ~ 0.25-4.5 × 1015 cm-2, with a fractional abundance of f (CO/H2) ~ 0.3-6 × 10-4. Column densities for HCO+ and H2CO were determined to be N tot ~ 0.2-5.5 × 1011 cm-2 and 0.2-1.6 × 1012 cm-2, respectively, with fractional abundances of f (HCO+/H2) ~ 0.3-7.3 × 10-8 and f (H2CO/H2) ~ 0.3-2.1 × 10-7—several orders of magnitude higher than predicted by chemical models. Polyatomic molecules in the Helix appear to be well-protected from photodissociation and may actually seed the diffuse interstellar medium.

Zack, L. N.; Ziurys, L. M.

2013-03-01

359

Turbulent Quasar Emission Line Clouds  

Microsoft Academic Search

Broad emission lines of Active Galactic Nuclei (AGN) are too bright to be powered by the continuum and too smooth to be produced by thermal clouds. One explanation is large-scale microturbulence. Turbulence has a significant effect on the shape and smoothness of AGN line profiles. If turbulence is in energy equipartition with gravity the line width of a cloud is

M. C. Bottorff; G. J. Ferland

2001-01-01

360

Active infrared hyperspectral imaging system using a broadly tunable optical parametric oscillator  

NASA Astrophysics Data System (ADS)

The in situ identification and spatial location of gases, discrete liquid droplets and residues on surfaces is a technically challenging problem. Active Infrared (IR) hyperspectral imaging is a powerful technique that combines real-time imaging and optical spectroscopy for "standoff" detection of suspected chemical substances, including chemical warfare agents, toxic industrial chemicals, explosives and narcotics. An active IR hyperspectral imaging system requires a coherent, broadly tunable IR light source of high spectral purity, in order to detect a broad range of target substances. In this paper we outline a compact and power-efficient IR illumination source with high stability, efficiency, tuning range and spectral purity based upon an optical parametric oscillator (OPO). The fusion of established OPO technology with novel diode-pumped laser technology and electro-mechanical scanning has enabled a broadly applicable imaging system. This system is capable of hyperspectral imaging at both Near-IR (1.3 - 1.9 ?m) and Mid-IR (2.3 - 4.6 ?m) wavelengths simultaneously with a line width of < 3 cm-1. System size and complexity are minimised by using a dual InGaAs/InSb single element detector, and images are acquired by raster scanning the coaxial signal and idler beams simultaneously, at ranges up to 20 m. Reflection, absorption and scatter of incident radiation by chemical targets and their surroundings provide a method for spatial location, and characteristic spectra obtained from each sample can be used to identify targets uniquely. To date, we have recognized liquids in sample sizes as small 20 ?l-and gases with sensitivity as high as 10ppm.m-at detection standoff distances > 10 m.

Malcolm, G. P. A.; Maker, G. T.; Robertson, G.; Dunn, M. H.; Stothard, D. J. M.

2009-09-01

361

Design of broad-band lumped-element baluns with inherent impedance transformation  

Microsoft Academic Search

This paper reports on a novel lumped balun topology, the second-order lattice balun, with broad-band performance. The design is based on synthetic transmission lines operating as impedance transformers. The characteristic impedance of the synthetic transmission lines may be chosen to obtain inherent impedance transformation. An analytical investigation results in closed formulas for optimum performance over a given bandwidth. It is

Dan Kuylenstierna; Peter Linnér

2004-01-01

362

A Martian Very Broad Band (VBB) Seismometer  

NASA Astrophysics Data System (ADS)

This paper exposes the latest technical developments made on the very broad band seismometer and the overall testing activities. This instrument is a seismic sensor designed for Mars, currently part of the core payload for the project InSight.

Robert, O.; Gagnepain-Beyneix, J.; Nebut, T.; Tillier, S.; Deraucourt, S.; Hurst, K.; Lognonne, P.; Banerdt, W. B.; Mimoun, D.; Bierwirth, M.; Calcutt, S.; Christenssen, U.; Giardini, D.; Kerjean, L.; Laudet, Ph.; Mance, D.; Perez, R.; Pike, T.; Roll, R.; Zweifel, P.; SEIS Team

2012-10-01

363

Broad and Columbia Subway Development Study.  

National Technical Information Service (NTIS)

The report was produced by an interdisciplinary team of university students demonstrating a constructive input into the planning and design of a transportation facility, the Broad and Columbia Subway Station. Subway station recommendations include provisi...

1971-01-01

364

Mycobacterium riyadhense sp. nov., a non-tuberculous species identified as Mycobacterium tuberculosis complex by a commercial line-probe assay.  

PubMed

A non-chromogenic, slowly growing Mycobacterium strain was isolated from a maxillary sinus lavage from a symptomatic patient in Riyadh, Saudi Arabia. It was initially identified as a member of the Mycobacterium tuberculosis complex by a commercial line-probe assay. Its 16S rRNA, hsp65 and rpoB gene and 16S-23S internal transcribed spacer sequences were unique; phylogenetic analysis based on the 16S rRNA gene sequence groups this organism close to Mycobacterium szulgai and Mycobacterium malmoense. Its unique biochemical properties and mycolic acid profile support separate species status. We propose the name Mycobacterium riyadhense sp. nov. to accommodate this strain. The type strain is NLA000201958(T) (=CIP 109808(T) =DSM 45176(T)). PMID:19406791

van Ingen, Jakko; Al-Hajoj, Sahal A M; Boeree, Martin; Al-Rabiah, Fahad; Enaimi, Mimount; de Zwaan, Rina; Tortoli, Enrico; Dekhuijzen, Richard; van Soolingen, Dick

2009-05-01

365

Effects of an inhibitor of the gamma-secretase complex on proliferation and apoptotic parameters in a FOXL2-mutated granulosa tumor cell line (KGN).  

PubMed

Ovarian granulosa cell tumors (GCTs) represent 3%-5% of all ovarian malignancies. Treatments have limited proven efficacy and biologically targeted treatment is lacking. The aim of this study was to investigate the role of Notch signaling in the proliferation, steroidogenesis, apoptosis, and phosphatidylinositol 3-kinase (PI3K)/AKT pathway in a FOXL2-mutated granulosa tumor cell line (KGN) representative of the adult form of GCTs. When Notch signaling is initiated, the receptors expose a cleavage site in the extracellular domain to the metalloproteinase TACE and, following this cleavage, Notch undergoes another cleavage mediated by the presenilin-gamma-secretase complex. To achieve our goal, DAPT, an inhibitor of the gamma-secretase complex, was used to investigate the role of the Notch system in parameters associated with cell growth and death, using a human granulosa cell tumor line (KGN) as an experimental model. We observed that JAGGED1, DLL4, NOTCH1, and NOTCH4 were highly expressed in KGN cells as compared to granulosa-lutein cells obtained from assisted reproductive techniques patients. The proliferation and viability of KGN cells, as well as progesterone and estradiol production, decreased in the presence of 20 ?M DAPT. Apoptotic parameters like PARP and caspase 8 cleavages, BAX, and BCLXs increased in KGN cells cultured with DAPT, whereas others such as BCL2, BCLXl, FAS, and FAS ligand did not change. AKT phosphorylation decreased and PTEN protein increased when Notch signaling was inhibited in KGN cells. We conclude that the Notch system acts as a survival pathway in KGN cells, and might be interacting with the PI3K/AKT pathway. PMID:23699387

Irusta, Griselda; Maidana, Camila Pazos; Abramovich, Dalhia; De Zúñiga, Ignacio; Parborell, Fernanda; Tesone, Marta

2013-07-11

366

Characterization of the Inhibitor of KappaB Kinase (IKK) Complex in Granulosa Cell Tumors of the Ovary and Granulosa Cell Tumor-Derived Cell Lines.  

PubMed

Granulosa cell tumors of the ovary (GCT) are a distinct, hormonally active subset of ovarian cancers. Although it has recently been shown that ?97 % of all adult GCT harbor a novel somatic missense mutation in the FOXL2 gene, given its almost universal presence, it does not explain differences in tumor stage and/or recurrence. The nuclear factor kappaB (NF?B) transcription factor is constitutively active in two human GCT-derived cell lines, COV434 and KGN, which are useful in vitro models to investigate juvenile and adult GCT, respectively. This study aimed to determine the molecular basis and pathogenetic significance of this aberrant NF?B activity. Selective chemical inhibitors were used to target candidate components of the pathway. The constitutive activity was blocked by two independent inhibitors of I?B? phosphorylation, suggesting that aberrant activation occurs upstream of this point. NF?B inhibition resulted in a dose-dependent decrease in cell proliferation and viability and a dose-dependent increase in apoptosis. Inhibitors of earlier components of the pathway were without effect. Two independent inhibitors of inhibitor of kappaB kinase (IKK)?, a catalytic subunit of the NF?B activation complex, were unable to inhibit the constitutive activity, but surprisingly also ligand-induced activity. These findings suggest a central role for IKK?; however, no mutations or altered expression of the IKK?, IKK?, or IKK? genes was observed in the cell lines or in a panel of human GCT samples. This study highlights unresolved issues in understanding the pathogenesis of GCT and in the use of the COV434 and KGN cells lines as model systems. PMID:23674259

Jamieson, Stacey; Fuller, Peter J

2013-05-15

367

Fluorocyclopentenyl-cytosine with broad spectrum and potent antitumor activity.  

PubMed

On the basis of the potent biological activity of cyclopentenyl-pyrimidines, fluorocyclopentenyl-pyrimidines were designed and synthesized from D-ribose. Among these, the cytosine derivative 5a showed highly potent antigrowth effects in a broad range of tumor cell lines and very potent antitumor activity in a nude mouse tumor xenograft model implanted with A549 human lung cancer cells. However, its 2'-deoxycytidine derivative 5b did not show any antigrowth effects, indicating that 2'-hydroxyl group is essential for the biological activity. PMID:22524616

Choi, Won Jun; Chung, Hwa-Jin; Chandra, Girish; Alexander, Varughese; Zhao, Long Xuan; Lee, Hyuk Woo; Nayak, Akshata; Majik, Mahesh S; Kim, Hea Ok; Kim, Jin-Hee; Lee, Young B; Ahn, Chang H; Lee, Sang Kook; Jeong, Lak Shin

2012-05-01

368

New heterobimetallic Cu(II)-Sn2(IV) complex as potential topoisomerase I inhibitor: in vitro DNA binding, cleavage and cytotoxicity against human cancer cell lines.  

PubMed

The new heterobimetallic Cu(II)-Sn(2)(IV)/Ni(II)-Sn(2)(IV) complexes 1 and 2 bearing bioactive pharmacophore ligand scaffold; 1,10-phenanthroline and ethylenediamine were synthesized and characterized by spectroscopic (IR, UV-vis, NMR, ESI-MS) and analytical methods. The in vitro DNA binding studies of 1 and 2 with CT-DNA were carried out by employing various biophysical methods which reveal strong electrostatic binding via phosphate backbone of DNA helix, in addition to partial intercalation in the minor groove and stabilized by intramolecular hydrogen bonding. To gain further insight into the molecular recognition at the target site, UV-vis titrations of 1 with 5'-GMP was carried out and validated by (1)H and (31)P NMR. Complex 1 cleaved pBR322 DNA via oxidative pathway and exhibited high inhibition activity against Topo-I at 20 ?M. Furthermore, the cytotoxicity of 1 was examined on a panel of human tumor cell lines of different histological origins showing promising antitumor activity. PMID:22884481

Tabassum, Sartaj; Afzal, Mohd; Arjmand, Farukh

2012-07-20

369

Direct on-line analysis of neutral analytes by dual sweeping via complexation and organic solvent field enhancement in nonionic MEKC.  

PubMed

Conventionally, neutral compounds cannot be separated by nonionic micelle capillary electrophoresis. In this report, the development of a novel on-line preconcentration technique combining dual sweeping based on complexation and organic solvent field enhancement is applied to the sensitive and selective analysis of three neutral glucosides: ginsenoside Rf, ginsenoside Rg1, and ginsenoside Re. Nonionic micelle detectability by CE is demonstrated through effective focusing of large sample volumes (up to 38% capillary length) using a dual sweeping mode. This results in a 50- to 130-fold improvement in the LODs relative to conventional injection method. Neutral compounds sweeping is examined in terms of analyte mobility dependence on borate complexation, solvent viscosity difference, and Brij-35 interaction. Enhanced focusing performance by this hyphenated method was demonstrated by a greater than fourfold reduction in glucoside bandwidth, as compared with common sweeping (devoid of organic solvent-mediated sweeping method in the sample matrices). Moreover, separation efficiencies greater than a million theoretical plates can be achieved by sweeping large sample volumes into narrow zones. The designated method was also tested for its ability to determine the presence of glucosides in the crude extracts obtained from plant sample. PMID:19382135

Cao, Jun; Li, Bin; Chang, Yan-Xu; Li, Ping

2009-04-01

370

NADPH-oxidase and a hydrogen peroxide-sensitive K+ channel may function as an oxygen sensor complex in airway chemoreceptors and small cell lung carcinoma cell lines  

PubMed Central

Pulmonary neuroepithelial bodies (NEB) are widely distributed throughout the airway mucosa of human and animal lungs. Based on the observation that NEB cells have a candidate oxygen sensor enzyme complex (NADPH oxidase) and an oxygen-sensitive K+ current, it has been suggested that NEB may function as airway chemoreceptors. Here we report that mRNAs for both the hydrogen peroxide sensitive voltage gated potassium channel subunit (KH2O2) KV3.3a and membrane components of NADPH oxidase (gp91phox and p22phox) are coexpressed in the NEB cells of fetal rabbit and neonatal human lungs. Using a microfluorometry and dihydrorhodamine 123 as a probe to assess H2O2 generation, NEB cells exhibited oxidase activity under basal conditions. The oxidase in NEB cells was significantly stimulated by exposure to phorbol esther (0.1 ?M) and inhibited by diphenyliodonium (5 ?M). Studies using whole-cell voltage clamp showed that the K+ current of cultured fetal rabbit NEB cells exhibited inactivating properties similar to KV3.3a transcripts expressed in Xenopus oocyte model. Exposure of NEB cells to hydrogen peroxide (H2O2, the dismuted by-product of the oxidase) under normoxia resulted in an increase of the outward K+ current indicating that H2O2 could be the transmitter modulating the O2-sensitive K+ channel. Expressed mRNAs or orresponding protein products for the NADPH oxidase membrane cytochrome b as well as mRNA encoding KV3.3a were identified in small cell lung carcinoma cell lines. The studies presented here provide strong evidence for an oxidase-O2 sensitive potassium channel molecular complex operating as an O2 sensor in NEB cells, which function as chemoreceptors in airways and in NEB related tumors. Such a complex may represent an evolutionary conserved biochemical link for a membrane bound O2-signaling mechanism proposed for other cells and life forms.

Wang, Dashou; Youngson, Charlotte; Wong, Veronica; Yeger, Herman; Dinauer, Mary C.; de Miera, Eleazar Vega-Saenz; Rudy, Bernardo; Cutz, Ernest

1996-01-01

371

Class-selective immunosorbent for trace-level determination of polycyclic aromatic hydrocarbons in complex sample matrices, used in off-line procedure or on-line coupled with liquid chromatography/fluorescence and diode array detections in series  

SciTech Connect

A new immunoaffinity solid-phase extraction (SPE) methodology based on antigen-antibody interactions was evaluated and optimized for the selective extraction of polycyclic aromatic hydrocarbons (PAHs) in various complex environmental matrices. This immunosorbent (IS) consists of anti-pyrene antibodies immobilized on a silica support and is used as a classical SPE sorbent. The cross-reactivity of the antibodies for analytes structurally related with pyrene allows the simultaneous extraction of the priority PAHs included in the European Union and/or US EPA priority lists. In addition, extraction, trace enrichment, and cleanup are achieved in one step due to the selectivity of the antigen-antibody interaction. For aqueous samples, limitation of unwanted adsorption of the PAHs on vessels or tubing due to their high hydrophobicity is obtained by adding acetonitrile in samples before percolation. Losses due to the volatility of the two- or three-ring PAHs are avoided by coupling on-line the extraction using the antipyrene IS with LC. From a sample volume of 80 mL, the sensitivity of the fluorescence associated with the selectivity of the IS allows the quantification of individual PAHs in contaminated or surface water below the 0.02 {micro}g/L level and therefore the fulfillment of the EU regulation for monitoring contaminated surface water used as a source for drinking water.

Bouzige, M.; Pichon, V.; Hennion, M.C. [Ecole Superieure de Physique et de Chimie Industrielles, Paris (France). Lab. Environnement et Chimie Analytique

1999-06-01

372

Towards a comprehensive X-ray approach for studying the photosynthetic manganese complex-XANES, K?/K?/K?-satellite emission lines, RIXS, and comparative computational approaches for selected model complexes  

NASA Astrophysics Data System (ADS)

Advanced X-ray spectroscopy experiments can contribute to elucidation of the mechanism of water oxidation in biological (tetra-manganese complex of Photosystem II) and artificial systems. Although the electronic structure of the catalytic metal site is of high interest, it is experimentally not easily accessible. Therefore, we and other researchers are working towards a comprehensive approach involving a combination of methods, namely (1) quantitative analysis of X-ray absorption near-edge structure (XANES) spectra collected at the K-edge and, in the long run, at the L-edge of manganese; (2) high-resolution X-ray emission spectroscopy (XES) of K? and K? lines, (3) two-dimensional resonant inelastic X-ray scattering (RIXS) spectra. Collection of these spectroscopic data sets requires state-of-the-art synchrotron radiation facilities as well as experimental strategies to minimize the radiation-induced modifications of the samples. Data analysis requires the use and development of appropriate theoretical tools. Here, we present exemplary data collected for three multi-nuclear synthetic Mn complexes with the Mn ions in the oxidation states II, III, and IV, and for MnVII of the permanganate ion. Emission spectra are calculated for the MnVII ion using both multiple-scattering (MS) approach and time-dependent density functional theory (TDDFT).

Zaharieva, I.; Chernev, P.; Risch, M.; Gerencser, L.; Berggren, G.; Shevchenko, D.; Anderlund, M.; Weng, T. C.; Haumann, M.; Dau, H.

2009-11-01

373

Widespread Synchronous Volcanism Reveals a Broad Galapagos Hotspot Melting Anomaly  

NASA Astrophysics Data System (ADS)

The massive aseismic ridges and associated seamounts dominating the morphology of the Panama Basin, eastern Central Pacific, have long been attributed to a Galapagos hotspot melting anomaly linked to a deep-seated mantle plume. Although these structures can provide information about the origin of hotspots and existence, or otherwise, of mantle plumes very little is known about their volcanic histories due to a lack of direct age and geochemical information. We report here 74 whole rock and 2 plagioclase 40Ar/39Ar ages for rocks dredged from 53 locations during the first systematic sampling of the Cocos, Carnegie, Coiba and Malpelo aseismic ridges and associated seamounts (F.S. SONNE PAGANINI expedition). In addition we also report ages for DSDP drill sites on Cocos, Carnegie and Coiba ridges and 7 Cocos Island subaerial samples. The distribution of new, and published ages for the Galapagos Archipelago-platform and NE end of the Cocos Ridge, show a general trend of increasing age with distance from the Galapagos Archipelago. A more dominant trend however is one of aseismic ridge-seamount formation in a progression of broad zones of synchronous, often overlapping volcanism created at discrete intervals. Broad zones of coeval Cocos and Carnegie volcanism once formed much larger regions of synchronous volcanism that have been split apart by the complex history of seafloor spreading associated with the Cocos-Nazca spreading center. We link these broad regions of synchronous volcanism to a correspondingly large hotspot melting anomaly. The present day, as yet unfragmented, zone of synchronous volcanism associated with this proposed broad hotspot is marked by the extensive region of recent volcanism extending across the Nazca and Cocos plates encompassing the Galapagos Archipelago-Platform and the Cocos Ridge as far north as Cocos Island. The complex tectonic history of the Cocos-Nazca spreading-center has controlled how the broad zones of synchronous, often overlapping volcanism created by the broad Galapagos melting anomaly have been fragmented between the Cocos and Nazca plates. However, interplay between the broad Galapagos melting anomaly and the Cocos-Nazca spreading center is a second-order process compared to a fundamental underlying mantle process responsible for a broad Galapagos hotspot melting anomaly exhibiting long-lived characteristics (size, time-progression, episodicity) which, on a first-order, are independent of local tectonics and lithospheric architecture. Evidence for a broad Galapagos hotspot melting anomaly and the possibility of detecting long-lived underlying mantle processes has implications for how oceanic hotspot volcanism is sampled for purposes of rigorously testing the mantle plume paradigm. A major question posed by our results is whether individual Pacific seamount chains are in fact the product of tectonic plate drift over narrow hotspots? If not, then inferring the existence and behavior of a mantle plume on the basis of age progression of volcanism produced by a narrow seamount chain could well prove to be misleading. Thus, although great leaps are being made in the theory and numerical modeling - often on a global scale - of hypothesized deep plumes, significantly more high-quality age and geochemical data are needed for oceanic hotspot volcanism that gave birth to the mantle plume hypothesis in the first place.

O'Connor, J. M.; Stoffers, P.; Wijbrans, J. R.; Worthington, T. J.

2004-12-01

374

A T-to-A substitution in the E1 alpha subunit gene of the branched-chain alpha-ketoacid dehydrogenase complex in two cell lines derived from Menonite maple syrup urine disease patients.  

PubMed

We cloned and sequenced cDNAs of the E1 alpha and E1 beta subunits of the branched chain alpha-ketoacid dehydrogenase complex (BCKDH) in two cell lines derived from two different Menonite MSUD patients (GM 1655, GM 1099). A T-to-A substitution which generates an asparagine in place of a tyrosine at amino acid 394 of the mature E1 alpha subunit was present in both alleles in these two cell lines, whereas cDNAs of the E1 beta subunit in these cell lines were identical to that of normal human lymphoid cell line and that of the clone from a human placenta cDNA library. It is suggested that the Menonite MSUD is caused by the missense mutation of the E1 alpha subunit of the BCKDH complex. PMID:2241958

Matsuda, I; Nobukuni, Y; Mitsubuchi, H; Indo, Y; Endo, F; Asaka, J; Harada, A

1990-10-30

375

Differential growth inhibition and enhancement of major histocompatibility complex class I antigen expression by interferons in a small-cell lung cancer cell line and its doxorubicin-selected multidrug-resistant variant  

Microsoft Academic Search

Summary Expression of class I and class II major histocompatibility complex antigens on a human small-cell lung cancer cell line and its multidrug-resistant variant was examined before and after exposure to interferon a (IFNa) and IFN? by flow cytometry. Neither IFNa nor IFN? induced class II antigen expression on the drug-sensitive or resistant cell line. Induction of class I antigen

S. P. C. Cole; B. M. T. Campigotto; J. G. Johnson; B. E. Elliott

1991-01-01

376

Kinetic study of a complex triangular reaction system in alkaline aqueous-ethanol medium using on-line transmission FTIR spectroscopy and BTEM analysis.  

PubMed

The kinetics of the base-catalyzed reaction of methyl 4-hydroxybenzoate in aqueous-ethanol solvent medium was studied and analyzed via combined on-line transmission FTIR spectroscopy and Band-Target Entropy Minimization (BTEM) technique. This reaction is considered complex since it involves simultaneous hydrolysis and ethanolysis reactions of methyl 4-hydrozybenzoate (MP) to form ethyl 4-hydroxybenzoate (EP) as an intermediate and sodium 4-hydroxybenzoate as a final product. The pure component spectra of the reactive species involved in the reaction were reconstructed using BTEM technique. Their corresponding real concentrations were calculated and subsequently used for analyzing the kinetics of this triangular reaction system. The effects of temperature and solvent mixture compositions were studied. In general, the results show that the rates of both hydrolysis and ethanolysis reactions increase with temperature. Addition of ethanol to the solvent mixture also reduces the rates of the hydrolysis reactions. The effect of solvent mixture on the rate of ethanolysis reaction is more complex and influenced by at least two competing factors, namely the concentration of ethoxide ion in the solution and the stabilization effect on the reactant. The enthalpy and entropy activation parameters, ?H(‡) and ?S(‡), of both the hydrolysis and ethanolysis reactions were determined using the Eyring equation and the activation parameters confirm the associative nature in the elementary steps in these reactions. Finally, it is shown that the dominant synthetic pathway in this triangular system changes from direct hydrolysis of methyl 4-hydrozybenzoate to the indirect pathway via ethanolysis and then hydrolysis depending on the solvent mixture composition. PMID:21962680

Tjahjono, Martin; Li, XiuRong; Tang, Fenglin; Sa-ei, Kanicha; Garland, Marc

2011-08-12

377

Narrow Absorption Line Outflows in High-Redshift Quasars  

NASA Astrophysics Data System (ADS)

We discuss results from a survey of narrow absorption lines (NALs) in high-resolution spectra of 24 high-redshift quasars. We identify NALs that are intrinsic to quasar environments based on partial covering of the background light source and, secondarily, broad rounded line profiles. The intrinsic lines tend to be stronger and broader, with larger CIV column densities, compared to other NALs with intervening or ambiguous origins. The large velocity shifts of many intrinsic lines, v > 2500 km s-1, clearly indicate an origin in quasar outflows. We describe some interesting individual cases, including very large outflow velocities up to ˜39,300 km s-1, and rich multi-component NAL complexes that also appear to have an outflow origin.

Simon, L. E.; Hamann, F.; Pettini, M.

2012-08-01

378

Procrastinators lack a broad action perspective  

Microsoft Academic Search

In the first study, the hypothesis was tested that in general optimistic procrastinators have chronically high action identities (i.e., a broad perspective on their actions), whereas pessimistic procrastinators have chronically low action identities to describe their behaviour. However, the data of the first study suggested that all procrastinators lack high action identities. The second study was set up to confront

Siegfried Dewitte; Willy Lens

2000-01-01

379

Broad Subjects and Clitic Left Dislocation  

Microsoft Academic Search

In this paper we have further defended the claim, set out in Doron and Heycock (1999), that a language in which nominative case can be checked by more than one element can allow merging of “Broad Subjects“ in [Spec,TP]. In this earlier work, we argued that such languages included Modern Hebrew and Modern Standard Arabic. Here we have further argued

Theodora Alexopoulou; Caroline Heycock

380

Ultra Broad Band RF Phase Shifter.  

National Technical Information Service (NTIS)

The patent application describes an ultra broad band RF phase shifter which includes a variable generator providing sine and cosine signals. A preselected RF signal is split into two equal phase and equal amplitude signals. One of the split signals is mod...

C. Malik

1973-01-01

381

Stark broadening of isolated lines: calculation of the diagonal multiplet factor for complex configurations (n1l1 n n2l2 m n3l3 p)  

NASA Astrophysics Data System (ADS)

Owing to the increasing sensitivity of detectors, accurate line profiles are needed for accurate stellar atmospheres modelling and for laboratory and technological plasmas as well. So, Stark broadening parameters of isolated lines of complex atoms and ions within the impact and quasistatic approximation are needed, even if the atomic abundance of the considered element is low. Angular factors of the diagonal line strength entering the quadrupole term appearing in the semi-classical expression of the width of line broadened by electron or ion perturbers, are needed. The aim of this paper is to extend the previous calculations of this diagonal multiplet factor which were obtained for configurations of the type ln and l1 nl2 m to more complex configurations in LS coupling. To study the Stark broadening of isolated lines in the impact and quasistatic approximation, we use the semi-classical-perturbation treatment, including both dipole and quadrupole contribution in the expansion of the electrostatic interaction between the optical electron and the perturber. We also use the Fano-Racah algebra. Angular factors of the diagonal line strength entering the quadrupole term appearing in the semi-classical expression of the width of line broadened by electron or ion perturbers, are calculated. New diagonal multiplet factor formulae for more complicated configurations such as (n1l1 n(LnSn)n2l2 m(LmSm)n3l3 p(LpSp)) are provided. These formulae can enter the computer Stark semi-classical perturbation codes.

Mahmoudi, W. F.; Ben Nessib, N.; Sahal-Bréchot, S.

2008-04-01

382

LINE-1 ORF1 Protein Localizes in Stress Granules with Other RNA-Binding Proteins, Including Components of RNA Interference RNA-Induced Silencing Complex? †  

PubMed Central

LINE-1 retrotransposons constitute one-fifth of human DNA and have helped shape our genome. A full-length L1 encodes a 40-kDa RNA-binding protein (ORF1p) and a 150-kDa protein (ORF2p) with endonuclease and reverse transcriptase activities. ORF1p is distinctive in forming large cytoplasmic foci, which we identified as cytoplasmic stress granules. A phylogenetically conserved central region of the protein is critical for wild-type localization and retrotransposition. Yeast two-hybrid screens revealed several RNA-binding proteins that coimmunoprecipitate with ORF1p and colocalize with ORF1p in foci. Two of these proteins, YB-1 and hnRNPA1, were previously reported in stress granules. We identified additional proteins associated with stress granules, including DNA-binding protein A, 9G8, and plasminogen activator inhibitor RNA-binding protein 1 (PAI-RBP1). PAI-RBP1 is a homolog of VIG, a part of the Drosophila melanogaster RNA-induced silencing complex (RISC). Other RISC components, including Ago2 and FMRP, also colocalize with PAI-RBP1 and ORF1p. We suggest that targeting ORF1p, and possibly the L1 RNP, to stress granules is a mechanism for controlling retrotransposition and its associated genetic and cellular damage.

Goodier, John L.; Zhang, Lili; Vetter, Melissa R.; Kazazian, Haig H.

2007-01-01

383

Migration of widespread long-lived volcanism across the Galápagos Volcanic Province: Evidence for a broad hotspot melting anomaly?  

NASA Astrophysics Data System (ADS)

The well-studied Galápagos Archipelago is a small part of the much larger Galápagos Volcanic Province (GVP) consisting of the Cocos, Carnegie, Coiba and Malpelo aseismic ridges and related seamount provinces. Although these aseismic ridges and seamounts dominate the morphology of the region, little is known about their origin due to a lack of direct age and geochemical information. In order to establish how well the GVP fits with the predictions of the 'standard' fixed hotspot and mantle plume hypotheses we conducted a first reconnaissance dredge/grab sampling of submerged regions of the GVP. We present here 40Ar/ 39Ar ages for many of these new basement samples and evaluate their implications for the various models put forward to explain the origin of the GVP. Correlating new and published sample-site ages with distance from the western side of the Galápagos Islands show that volcanism has not progressed in narrow, time-progressive lines of seamounts and ridges as predicted by the conventional fixed hotspot and mantle plume hypothesis. Rather, volcanism apparently migrated time-progressively across the GVP in broad regions of long-lived and possibly concurrent volcanism. We propose that the most viable explanation for these observations is that the GVP is the product of Cocos and Nazca plate motions across a broad hotspot melt anomaly. The complex spreading history of the Cocos-Nazca spreading centre likely controlled the relative distribution of GVP volcanism between the Cocos and Nazca plates while creating lithosphere of variable age/thickness across the region. While the notion of a broad Galápagos hotspot melting anomaly linked to a complex regional tectonic history requires significant testing it nevertheless highlights the need to test alternative mantle upwelling shapes and sizes compared to the widely accepted notion of a narrow continuous long-lived Galápagos mantle plume conduit defined by the size and location of a Galápagos island.

O'Connor, John M.; Stoffers, Peter; Wijbrans, Jan. R.; Worthington, Tim J.

2007-11-01

384

4. A river level view of the Broad Street bridge ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. A river level view of the Broad Street bridge and Columbus skyline from the railroad truss north of the bridge. - Broad Street Bridge, Spanning Scioto River at U.S. Route 40 (Broad Street), Columbus, Franklin County, OH

385

2. SOUTH FRONT, MAIN SECTION, LOOKING NORTH; 92 BROAD STREET ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. SOUTH FRONT, MAIN SECTION, LOOKING NORTH; 92 BROAD STREET VISIBLE AT LEFT EDGE OF PHOTOGRAPH, INFILL SECTION OF 90 BROAD STREET VISIBLE AT RIGHT EDGE OF PHOTOGRAPH - 90 Broad Street (Commercial Building), Charleston, Charleston County, SC

386

9. The southeast face of the Broad Street bridge with ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. The southeast face of the Broad Street bridge with City Hall in the background as seen from Amphitheater Park. - Broad Street Bridge, Spanning Scioto River at U.S. Route 40 (Broad Street), Columbus, Franklin County, OH

387

Elevation of dwelling at 80 North Broad Place, SW, originally ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Elevation of dwelling at 80 North Broad Place, SW, originally built to house workers from the nearby Merrimack Mill - 80 North Broad Place, Southwest (House), 80 North Broad Place, Southwest , Huntsville, Madison County, AL

388

3. PERSPECTIVE VIEW OF CORNER OF BROAD AND WATER STREETS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. PERSPECTIVE VIEW OF CORNER OF BROAD AND WATER STREETS (FRAUNCES TAVERN IS ON FAR LEFT, LOOKING DOWN BROAD STREET) - Fraunces Tavern Block, Bounded by Pearl, Water & Broad Streets & Coeties Slip, New York, New York County, NY

389

7. BROAD STREET STATION (demolished 1953). Photocopy of ca. 1894 ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. BROAD STREET STATION (demolished 1953). Photocopy of ca. 1894 photograph by William H. Rau. Original photograph at Pennsylvania Railroad - Pennsylvania Railroad Station, Broad Street Station, Broad & Market Streets, Philadelphia, Philadelphia County, PA