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1

The Suzaku Observation of NGC 3516: Complex Absorption and the Broad and Narrow Fe K Lines  

NASA Technical Reports Server (NTRS)

We present results from a 150 ksec Suzaku observation of the Seyfert 1 NGC 3516 in October 2005. The source was in a relatively highly absorbed state. Our best-fit model is consistent with partial covering by a lowly-ionized absorber with a column density near 5x10(exp 22) cm(exp -2) and with a covering fraction 96-100 percent. Narrow K-shell absorption features due to He- and H-like Fe confirm the presence of a high-ionization absorbing component as well. A broad Fe K(alpha) diskline is required in all fits, even after the complex absorption is taken into account; an additional partial-covering component is an inadequate substitute for the continuum curvature associated with the broad line. The narrow Fe Ka line at 6.4 keV is resolved, yielding a velocity width commensurate with the optical Broad Line Region. The strength of the Compton reflection hump suggests a contribution mainly from the broad Fe line origin. We include in our model soft band emission lines from He- and H-like ions and radiative recombination lines, consistent with photo-ionization, though a small contribution from collisional ionization is possible.

Markowitz, Alex; Reeves, James N.; Miniutti, Giovanni; Serlemitsos, Peter; Kunieda, Hideyo; Taqoob, Tahir; Fabian, Andrew C.; Fukazawa, Yasushi; Mushotzky, Richard; Okajima, Takashi; Gallo, Luigi; Awaki, Hisamitsu; Griffiths, Richard E.

2007-01-01

2

Structure and Variability in Broad Absorption Lines of Quasar Spectra  

Microsoft Academic Search

We present spectroscopic observations of two Broad Absorption Line (BAL) QSOs 0752 + 617 and 0932 + 501, represending different classes in the complexity of structures in the absorption troughs. Our aim is the determination of column densities and the analysis of the absorption line fine structures. Applying a Gauss-analysis of the absorption line profiles we show that the troughs

V. L. Afanasjev; E. A. Nazarov; Hilmar Lorenz

1991-01-01

3

Structure and variability in broad absorption lines of quasar spectra  

Microsoft Academic Search

We present spectroscopic observations of two Broad Absorption Line (BAL) QSOs 0752 + 617 and 0932 + 501, represending different classes in the complexity of structures in the absorption troughs. Our aim is the determination of column densities and the analysis of the absorption line fine structures. Applying a Gauss-analysis of the absorption line profiles we show that the troughs

V. Afanasjev; E. Nazarov; Hilmar Lorenz

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

Spectrophotometry of six broad absorption line QSOs  

NASA Technical Reports Server (NTRS)

Spectrophotometric observations of six broad absorption-line QSOs (BALQSOs) are presented. The continua and emission lines are compared with those in the spectra of QSOs without BALs. A statistically significant difference is found in the emission-line intensity ratio for (N V 1240-A)/(C IV 1549-A). The median value of (N V)/(C IV) for the BALQSOs is two to three times the median for QSOs without BALs. The absorption features of the BALQSOs are described, and the column densities and limits on the ionization structure of the BAL region are discussed. If the dominant ionization mechanism is photoionization, then it is likely that either the ionizing spectrum is steep or the abundances are considerably different from solar. Collisional ionization may be a significant factor, but it cannot totally dominate the ionization rate.

Junkkarinen, Vesa T.; Burbidge, E. Margaret; Smith, Harding E.

1987-01-01

6

Influence of Physical Aging on the State of Water Strongly Bound by the Polyvinylpyrrolidone-Poly(ethylene glycol) Complex by Broad-Line 1 H NMR Data  

Microsoft Academic Search

The mobility of the components of a mixture of high-molecular-weight polyvinylpyrrolidone and poly(ethylene glycol) containing 36 vol % of PEG with a molecular mass of 400 and about 1 wt % of water was studied by the broad-line 1H NMR technique at mixture storage times of 4, 8, and 12 months. It was shown that, during the mixture storage, the

V. F. Chuvaev; R. Sh. Vartapetyan; M. M. Fel'dshtein

2004-01-01

7

Spectral investigation of quasars with broad absorption lines  

Microsoft Academic Search

The results of spectral studies of quasars with broad absorption lines (0932 + 501 and 0752 + 617) selected from the Tautenburg survey are presented. The positions of the emission lines in the spectra correspond to 1.904 for 0932 + 501 and 1.892 for 0752 + 617, respectively. It is found that broad absorption lines have a complicated structure.

V. L. Afanas'ev; H. Lorenz; E. A. Nazarov

1989-01-01

8

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

9

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

10

PG 1411 + 442 - The nearest broad absorption line quasar  

NASA Technical Reports Server (NTRS)

IUE observations reveal strong, moderately broad absorption troughs in the blue wings of the C IV and N V emission lines of the quasar PG 1411 + 442. No absorption from weakly ionized gas is detected. The emission-line strengths and overall shape of the ultraviolet/optical/near-infrared/far-infrared continuum of the new broad absorption line quasar are within the range normally measured in quasars. Its redshift is low enough to allow the morphology of the host galaxy to be studied in deep broad-band and intermediate-band CCD images. The galaxy appears to be a large spiral with a very long arm or tail. The inclination angle is 57 deg, which rules out the possibility that the line of sight to the nucleus intersects a large path length in a galactic disk.

Malkan, Matthew A.; Green, Richard F.; Hutchings, John B.

1987-01-01

11

Complex Line Integrals I  

NSDL National Science Digital Library

Created by Lang More of the Connected Curriculum Project, the purpose of this module is to investigate the behavior of complex line integrals. This is one lesson within a much larger set of learning modules hosted by Duke University.

Moore, Lang

2010-06-21

12

Diverse Broad Line Region Kinematic Signatures From Reverberation Mapping  

Microsoft Academic Search

A detailed analysis of the data from a high sampling rate, multi-month\\u000areverberation mapping campaign, undertaken primarily at MDM Observatory with\\u000asupporting observations from telescopes around the world, reveals that the\\u000aHbeta emission region within the broad line regions (BLRs) of several nearby\\u000aAGNs exhibit a variety of kinematic behaviors. While the primary goal of this\\u000acampaign was to obtain

K. D. Denney; B. M. Peterson; R. W. Pogge; A. Adair; D. W. Atlee; K. Au-Yong; M. C. Bentz; J. C. Bird; D. J. Brokofsky; E. Chisholm; M. L. Comins; M. Dietrich; V. T. Doroshenko; J. D. Eastman; Y. S. Efimov; S. Ewald; S. Ferbey; C. M. Gaskell; C. H. Hedrick; K. Jackson; S. A. Klimanov; E. S. Klimek; A. K. Kruse; A. Ladéroute; J. B. Lamb; K. Leighly; T. Minezaki; S. V. Nazarov; C. A. Onken; E. A. Petersen; P. Peterson; S. Poindexter; Y. Sakata; K. J. Schlesinger; S. G. Sergeev; N. Skolski; L. Stieglitz; J. J. Tobin; C. Unterborn; M. Vestergaard; A. E. Watkins; L. C. Watson; Y. Yoshii

2009-01-01

13

Broad Research Project on the Sciences of Complexity.  

National Technical Information Service (NTIS)

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 spec...

2002-01-01

14

Variability in Low Ionization Broad Absorption Line outflows  

NASA Astrophysics Data System (ADS)

We present results of our time variability studies of Mg II and Al III absorption lines in a sample of 22 Low Ionization Broad Absorption Line QSOs (LoBAL QSOs) at 0.2 ? zem ? 2.1 using the 2-m telescope at IUCAA Girawali Observatory over a time-scale of 10 d to 7.69 years in the QSO's rest frame. Spectra are analysed in conjunction with photometric light curves from Catalina Real-Time Transient Survey. Long time-scale (i.e. ?1 year) absorption line variability is seen in eight cases (36 per cent systems) while only four of them (i.e. 18 per cent systems) show variability over short time-scales (i.e. <1 year). We notice a tendency of highly variable LoBAL QSOs to have high ejection velocity, low equivalent width and low redshift. The detection rate of variability in LoBAL QSOs showing Fe fine-structure lines (FeLoBAL QSOs) is less than that seen in non-Fe LoBAL QSOs. Absorption line variability is more frequently detected in QSOs having continuum dominated by Fe emission lines compared to rest of the QSOs. Confirming these trends with a bigger sample will give vital clues for understanding the physical distinction between different BAL QSO sub-classes. We correlate the absorption line variability with various parameters derived from continuum light curves and find no clear correlation between continuum flux and absorption line variabilities. However, sources with large absorption line variability also show large variability in their light curves. We also see appearance/disappearance of absorption components in two cases and clear indications for profile variations in four cases. The observed variability can be best explained by a combination of process driven by continuum variations and clouds transiting across the line of sight.

Vivek, M.; Srianand, R.; Petitjean, P.; Mohan, V.; Mahabal, A.; Samui, S.

2014-05-01

15

Probing AGN Broad Line Regions With LAT Observations of FSRQs  

SciTech Connect

The GLAST Large Area Telescope (LAT) is expected to detect gamma-ray emission from over a thousand active galaxies, many of which will be flat spectrum radio quasars (FSRQs). A commonly assumed ingredient of leptonic models of FRSQs is the contribution to the gamma-ray flux from external inverse-Compton (EIC) scattering of photons from the broad line region (BLR) material by relativistic electrons and positrons in the jet. Here we explore the effect of the BLR geometry on the high-energy emission from FSRQs.

Carson, Jennifer E.; Chiang, James; /SLAC; Bottcher, Markus; /Ohio U.

2007-10-11

16

X-ray Obscured Broad-Line AGN  

NASA Astrophysics Data System (ADS)

While the vast majority of Type I AGN show little or no X-ray obscuration, approximately 10% are heavily obscured with X-ray column densities of N_H > 10^22 cm^-2. In addition to providing a unique and necessary test of the unified model, the study of these AGN has significant consequences for our understanding of the cosmic X-ray and infrared backgrounds, and therefore for the cosmic accretion and star-formation histories of the universe. A number of explanations have been proposed to explain the seemingly contradictory behavior of these X-ray obscured, broad-line AGN, including (1) dust sublimation near the central engine, (2) dust coagulation, (3) obscuration by clouds in the broad-line region, (4) column density variability, and (5) scattering of the broad emission lines off a reflecting medium. We therefore propose for MIPS and IRAC observations of the 11 sources in our sample of 13 for which this data is not yet available. In addition, we propose low-resolution IRS spectroscopy for the brightest 5 sources as well as 1 faint source with an exceptionally high column density, and IRS Peak-Up imaging at 16 microns for the remaining 7 sources. The MIPS, IRAC, and IRS Peak-Up photometry will allow us to test for the presence of hot dust, which may be in the process of being destroyed through dust sublimation. IRS spectroscopy will allow us to test for the presence of the 9.7 micron silicate feature, which should not be present if the dust distribution is dominated by large grains as predicted in some models, or which may be seen in emission if the broad-line region clouds are themselves responsible for the odd behavior of these AGN. In combination with polarimetric data and high-quality optical spectra from the Bok 90' telescope, these observations will provide us with the ideal dataset to test concretely for the first time the many potential explanations for the strange behavior of these unexpected AGN.

Rieke, George; Donley, Jennifer; Shi, Yong; Smith, Paul

2008-03-01

17

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

18

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

19

The Redshifted Excess in Quasar C IV Broad Emission Lines  

NASA Astrophysics Data System (ADS)

In this paper, the Evans and Koratkar Atlas of Hubble Space Telescope Faint Object Spectrograph Spectra of Active Galactic Nuclei and Quasars is used to study the redward asymmetry in C IV broad emission lines (BELs). It is concluded that there is a highly significant correlation between the spectral index from 10 GHz to 1350 Å and the amount of excess luminosity in the red wing of the C IV BEL (>99.9999% significance level for the full sample and the radio-loud subsample independently, but no correlation is found for the radio-quiet subsample). This is interpreted as a correlation between radio core dominance and the strength of the C IV redward asymmetry. The data imply that within the quasar environment there is BEL gas with moderately blueshifted emission associated with the purely radio-quiet quasar (RQQ) phenomenon (the accretion disk), and the radio jet emission mechanism is associated with a redward BEL component that is most prominent for lines of sight along the jet axis. Thus, RQQs have C IV BELs that tend to show blueshifted excess, and radio-loud quasars show either a red or blue excess with the tendency for a dominant red excess increasing as the line-of-sight approaches the jet axis.

Punsly, Brian

2010-04-01

20

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

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

Outflow and Hot Dust Emission in Broad Absorption Line Quasars  

NASA Astrophysics Data System (ADS)

We have investigated a sample of 2099 broad absorption line (BAL) quasars with z = 1.7-2.2 built from the Sloan Digital Sky Survey Data Release Seven and the Wide-field Infrared Survey. This sample is collected from two BAL quasar samples in the literature and is refined by our new algorithm. Correlations of outflow velocity and strength with a hot dust indicator (?NIR) and other quasar physical parameters—such as an Eddington ratio, luminosity, and a UV continuum slope—are explored in order to figure out which parameters drive outflows. Here ?NIR is the near-infrared continuum slope, which is a good indicator of the amount of hot dust emission relative to the accretion disk emission. We confirm previous findings that outflow properties moderately or weakly depend on the Eddington ratio, UV slope, and luminosity. For the first time, we report moderate and significant correlations of outflow strength and velocity with ?NIR in BAL quasars. It is consistent with the behavior of blueshifted broad emission lines in non-BAL quasars. The statistical analysis and composite spectra study both reveal that outflow strength and velocity are more strongly correlated with ?NIR than the Eddington ratio, luminosity, and UV slope. In particular, the composites show that the entire C IV absorption profile shifts blueward and broadens as ?NIR increases, while the Eddington ratio and UV slope only affect the high and low velocity part of outflows, respectively. We discuss several potential processes and suggest that the dusty outflow scenario, i.e., that dust is intrinsic to outflows and may contribute to the outflow acceleration, is most likely.

Zhang, Shaohua; Wang, Huiyuan; Wang, Tinggui; Xing, Feijun; Zhang, Kai; Zhou, Hongyan; Jiang, Peng

2014-05-01

23

The Physical Nature of Polar Broad Absorption Line Quasars  

NASA Technical Reports Server (NTRS)

It has been shown based on radio variability arguments that some BALQSOs (broad absorption line quasars) are viewed along the polar axis (o rthogonal to accretion disk) in the recent article of Zhou et a. Thes e arguments are based on the brightness temperature, T(sub b) exceedi ng 10(exp 12) K which leads to the well-known inverse Compton catastr ophe unless the radio jet is relativistic and is viewed along its axi s. In this letter, we expand the Zhou et al sample of polar BALQSOs u sing their techniques applied to SDSS DR5. In the process, we clarify a mistake in their calculation of brightness temperature. The expanded sample of high T(sub b) BALQSOS, has an inordinately large fraction of LoBALQSOs (low ionization BALQSOs). We consider this an important clue to understanding the nature of the polar BALQSOs. This is expec ted in the polar BALQSO analytical/numerical models of Punsly that pr edicted that LoBALQSOs occur when the line of sight is very close to the polar axis, where the outflow density is the highest.

Ghost, Kajal; Punsly, Brian

2007-01-01

24

Significant Contribution of the Cerenkov Line-like Radiation to the Broad Emission Lines of Quasars  

NASA Astrophysics Data System (ADS)

The Cerenkov line-like radiation in a dense gas (N H > 1013 cm-3) is potentially important in the exploration of the optical broad emission lines of quasars and Seyfert 1 galaxies. With this quasi-line emission mechanism, some long standing puzzles in the study of quasars could be resolved. In this paper, we calculate the power of the Cerenkov line-like radiation in dense gas and compare with the powers of other radiation mechanisms by a fast electron to confirm its importance. From the observed gamma-ray luminosity of 3C 279, we show that the total number of fast electrons is sufficiently high to allow effective operation of the quasi-line emission. We present a model calculation for the luminosity of the Cerenkov Ly? line of 3C 279, which is high enough to compare with observations. We therefore conclude that the broad line of quasars may be a blend of the Cerenkov emission line with the real line produced by the bound-bound transition. A new approach to the absorption of the Cerenkov line is presented with the method of escape probability, which markedly simplifies the computation in the optically thick case. The revised set of formulae for the Cerenkov line-like radiation is more convenient in applications.

Liu, D. B.; Chen, W. P.; You, J. H.; Chen, L.

2014-01-01

25

Broad Absorption Line Quasars Observed by the ROSAT PSPC  

NASA Technical Reports Server (NTRS)

Recent results from the ROSAT All-Sky Survey have shown that Broad Absorption Line (BAL) QSOs are either highly absorbed or underluminous in the soft X-ray bandpass. Here we extend this work by analyzing all known bona fide BAL QSOs observed within the inner 20 min of the ROSAT Position Sensitive Proportional Counter. This sample includes both targeted and serendipitous exposures ranging from 8 to 75 ks. Despite these deep exposures, most of the BAL QSOs are undetected and have unusually weak X-ray emission, as evidenced by large optical-to-X-ray slopes alpha(sub ox). Large values of alpha(sub ox)(approx. greater than 1.8) may prove to be a defining characteristic of BAL QSOs. We predict that samples of QSO candidates with large alpha(sub ox) will yield a higher percentage of BAL QSOs, particularly at low redshift. As a corollary, X-ray selected QSO samples should yield fewer BAL QSOs. The optical/UV emission line spectra of BAL and non-BAL QSOs are quite similar, suggesting that their intrinsic spectral energy distributions are similar as well. Absorption thus seems the likely reason for the X-ray-quiet nature of BAL QSOs. To constrain the total absorbing column of the BAL clouds, we compare our measured soft X-ray fluxes or upper limits with those expected from normal radio-quiet QSOs of comparable optical continuum magnitude and redshift. From sensitive X-ray observations, we derive column densities of approx. less than 2 x 10(exp 22)/sq cm for intrinsic cold absorbers of solar metallicity. These new results suggest columns at least an order of magnitude larger than the columns previously estimated from optical/UV spectra alone.

Green, Paul J.; Mathur, Smita

1997-01-01

26

X-Ray Continua of Broad Absorption Line Quasars  

NASA Technical Reports Server (NTRS)

The targets for this program, PG1416-129 and LBQS 2212-1759 were known to be Broad Absorption Line Quasars (BALQSOs). BALQSOs are highly absorbed in soft X-rays. Good high energy response of Rossi-XTE made them ideal targets for observation. We observed LBQS 2212-1759 with PCA. We have now analyzed the data and found that the source was not detected. Since our target was expected to be faint, reliable estimate of background was very important. With the release of new FTOOLS (version 4.1) we were able to do so. We also analyzed a well known bright object and verified our results with the published data. This gave us confidence in the non-detection of our target LBQS 2212-1759. We are currently investigating the implications of this non-detection. Due to some scheduling problems, our second target PG1416-129 was not observed in A01. It was observed on 06/26/98. This target was detected with RXTE. We are now working on the spectral analysis with XSPEC.

Mathur, S.

1999-01-01

27

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

28

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

29

Non-steady state line locking in broad absorption line quasi-stellar objects  

NASA Astrophysics Data System (ADS)

A nonsteady state model for absorption-absorption line locking in broad absorption line quasars is discussed in which an approximate balance between the forces is not required. It is assumed that locking is on velocity differences, not on absolute velocities relative to the central source. The locking occurs between two gas elements neither of which is at a constant velocity, and it is only the relative velocity between the two that remains constant and equal to the doublet velocity. This picture can work equally well for decelerating gas and can also work for objects which exhibit large luminosity fluctuations.

Braun, Erez; Milgrom, Mordehai

1989-07-01

30

Emergence of double-peaked emission lines in the broad-line radio galaxy Pictor A  

NASA Technical Reports Server (NTRS)

A new optical spectrum of the nearby broad-line radio galaxy (BLRG) Pictor A reveals a prominent double-peaked component of the Balmer lines which does not appear in any historical spectra of this object. Carried out with the hope of obtaining exactly such a result, this observation is a key to the interpretation of double-peaked emitters. If bolsters our previous conclusion that there is a set of additional properties which are associated with the rare class of double-peaked emitters, namely F-R II radio morphology, strong low-ionization forbidden lines, weak UV continuum, and flat far-infrared spectrum. Furthermore, the low-velocity, 'ordinary' broad Balmer lines in Pictor A remained relatively unchanged as the new twin peaks appeared, which justifies the practice of applying models that fit only the double peaks and not the low-velocity components that are often present in spectra of this type. We discuss the relative merits of accretion-disk models and other models for double-peaked emission lines in the light of this new observation.

Halpern, Jules P.; Eracleous, Michael

1994-01-01

31

Anisotropic line emission and the geometry of the broad-line region in active galactic nuclei  

NASA Technical Reports Server (NTRS)

Attention is given to an escape probability-based formalism, including the interaction with a background opacity, which is used to predict line-beaming factors for broad-line region (BLR) clouds of AGN. Several computational details necessary to model gas exposed to an intense nonthermal continuum are outlined. It is found that all hydrogen lines are strongly inwardly beamed, and that C IV 1549 is moderately beamed. The implications of this for the geometry of the emission-line regions of AGN are discussed. Beaming is found to cause the source-cloud separation to be overestimated by variability studies (so that the radiation field at the BLR is even more intense than previously thought); it can even cause spherical geometries to have little instantaneous response to continuum changes.

Ferland, G. J.; Peterson, B. M.; Horne, K.; Welsh, W. F.; Nahar, S. N.

1992-01-01

32

Broad emission lines: A tool for studying nuclei of active galaxies  

NASA Astrophysics Data System (ADS)

Active galactic nuclei (AGNs) are objects hosting in their center a super-massive black hole (SMBH) with an accretion disk surrounded by gas and dust. The mass of an SMBH can be derived from the dynamics of the gas gravitationally bounded to the SMBH. This is the case for the broad line region (BLR), i.e. a photoionized gas in the vicinity of an SMBH that emits broad emission lines (BELs), which properties can be used to estimate the mass of the SMBH. In spite of a number of papers devoted to the BLR research, its true nature is not well known. Therefore, it is still important to investigate the BLR structure (size, geometry, physics, etc.), where one of the aims is to better constrain the mass of the SMBH in the center of AGNs. The BELs are the only signatures of the BLR physics and geometry. They can be clearly identified in AGN spectra and they often show complex profiles. Their fluxes, profiles and ratios can provide much information about the BLR geometry and physics. Moreover, the BELs and continuum flux are very often varying in AGNs. Therefore, an investigation of the BEL flux and profile variability during a long period is another useful tool for mapping the geometrical and dynamical structure of the BLR. In this review we present and discuss some tools and techniques for studying the structure of the BLR using broad emission line properties.

Ili?, Dragana; Popovi?, Luka ?.; Shapovalova, Alla I.; Burenkov, Alexander N.; Kollatschny, Wolfram; Kova?evi?, Andjelka; Chavushyan, Vahram; La Mura, Giovanni; Rafanelli, Piero

2012-12-01

33

[Ecological care as a broad and complex phenomenon].  

PubMed

This study aimed to comprehending the meaning of ecological care from the point of view of students and teachers of the health area of a Public Institution of Higher Education. It was an exploratory qualitative research conducted by the method of the Theory Based on the Data, for which ten in depth interviews were carried out between September/2008 and April/2009, distributed in two sample groups. The process of data collection and analysis culminated with the formulation of the theory "Viewing ecological care as a broad and complex phenomenon", which was discussed through the view of complexity. One concluded that the academic environment is constituted by an appropriate space for the development of the systemic abilities, capable of contemplating the relations, interactions and necessary associations for the comprehension and promotion of the environmental sustainability. PMID:22460489

Backes, Marli Terezinha Stein; Backes, Dirce Stein; Drago, Lívia Crespo; Koerich, Magda Santos; Erdmann, Alacoque Lorenzini

2011-01-01

34

LINE SHIFTS, BROAD-LINE REGION INFLOW, AND THE FEEDING OF ACTIVE GALACTIC NUCLEI  

SciTech Connect

Velocity-resolved reverberation mapping suggests that the broad-line regions (BLRs) of active galactic nuclei (AGNs) can have significant net inflow. We use the STOKES radiative transfer code to show that electron and Rayleigh scattering off the BLR and torus naturally explains the blueshifted profiles of high-ionization lines and the ionization dependence of the blueshifts. This result is insensitive to the geometry of the scattering region. If correct, then this model resolves the long-standing conflict between the absence of outflow implied by velocity-resolved reverberation mapping and the need for outflow if the blueshifting is the result of obscuration. The accretion rate implied by the inflow is sufficient to power the AGN. We suggest that the BLR is part of the outer accretion disk and that similar magnetohydrodynamic processes are operating. In the scattering model, the blueshifting is proportional to the accretion rate so high-accretion-rate AGNs will show greater high-ionization line blueshifts, as is observed. Scattering can lead to systematically too high black hole mass estimates from the C IV line. We note many similarities between narrow-line region (NLR) and BLR blueshiftings, and suggest that NLR blueshiftings have a similar explanation. Our model explains the higher blueshifts of broad absorption line QSOs if they are more highly inclined. Rayleigh scattering from the BLR and torus could be more important in the UV than electron scattering for predominantly neutral material around AGNs. The importance of Rayleigh scattering versus electron scattering can be assessed by comparing line profiles at different wavelengths arising from the same emission-line region.

Gaskell, C. Martin [Department of Astronomy, University of Texas, Austin, TX 78712-0259 (United States); Goosmann, Rene W., E-mail: martin.gaskell.astro@gmail.com, E-mail: rene.goosmann@astro.unistra.fr [Astronomical Institute of the Academy of Sciences, Bocni II 1401, 14131 Prague (Czech Republic)

2013-05-20

35

DISCOVERY OF THE TRANSITION OF A MINI-BROAD ABSORPTION LINE INTO A BROAD ABSORPTION LINE IN THE SDSS QUASAR J115122.14+020426.3  

SciTech Connect

We present the detection of a rare case of dramatic strengthening in the UV absorption profiles in the spectrum of the quasar J115122.14+020426.3 between observations {approx}2.86 yr apart in the quasar rest frame. A spectrum obtained in 2001 by the Sloan Digital Sky Survey shows a C IV ''mini-broad'' absorption line (FWHM = 1220 km s{sup -1}) with a maximum blueshift velocity of {approx}9520 km s{sup -1}, while a later spectrum from the Very Large Telescope shows a significantly broader and stronger absorption line, with a maximum blueshift velocity of {approx}12, 240 km s{sup -1} that qualifies as a broad absorption line. A similar variability pattern is observed in two additional systems at lower blueshifted velocities and in the Ly{alpha} and N V transitions as well. One of the absorption systems appears to be resolved and shows evidence for partial covering of the quasar continuum source (C{sub f} {approx} 0.65), indicating a transverse absorber size of, at least, {approx}6 Multiplication-Sign 10{sup 16} cm. In contrast, a cluster of narrower C IV lines appears to originate in gas that fully covers the continuum and broad emission line sources. There is no evidence for changes in the centroid velocity of the absorption troughs. This case suggests that at least some of the absorbers that produce ''mini-broad'' and broad absorption lines in quasar spectra do not belong to intrinsically separate classes. Here, the ''mini-broad'' absorption line is most likely interpreted as an intermediate phase before the appearance of a broad absorption line due to their similar velocities. While the current observations do not provide enough constraints to discern among the possible causes for this variability, future monitoring of multiple transitions at high resolution will help achieve this goal.

Hidalgo, Paola Rodriguez; Eracleous, Michael; Charlton, Jane [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Hamann, Fred [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Murphy, Michael T. [Center for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122 (Australia); Nestor, Daniel [Department of Physics and Astronomy, University of California, 430 Portola Plaza, Box 951547, Los Angeles, CA 90095 (United States)

2013-09-20

36

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

37

The hypothesis of the dust origin of the Broad Line Region in Active Galactic Nuclei  

Microsoft Academic Search

Strong broad emission lines are the most important signatures of active galactic nuclei. These lines allowed to discover the cosmological nature of quasars, and at present these lines allow for convenient method of weighting the black holes residing in their nuclei. However, a question remains why such strong lines form there in the first place. Specifically, in the case of

Bozena Czerny; Krzysztof Hryniewicz

2012-01-01

38

Double-peaked Broad Emission Lines in NGC 4450 and Other LINERS  

Microsoft Academic Search

Spectra taken with the Hubble Space Telescope (HST) reveal that NGC 4450 emits Balmer emission lines with displaced double peaks and extremely high velocity wings. This characteristic line profile, previously seen in a few nearby LINERs and in a small fraction of broad-line radio galaxies, can be interpreted as a kinematic signature of a relativistic accretion disk. We can reproduce

Luis C. Ho; Greg Rudnick; Hans-Walter Rix; Joseph C. Shields; Daniel H. McIntosh; Alexei V. Filippenko; Wallace L. W. Sargent; Michael Eracleous

2000-01-01

39

What the Optical Recombination Lines Can Tell Us about the Broad-Line Regions of Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

We investigate the effect of a global change in the ionizing continuum level on the behavior of the strong optical broad emission lines seen in spectra of the nuclear emission-line regions of active galactic nuclei (AGNs), including the Balmer lines, He I ?5876, and He II ?4686. Unlike most of the prominent heavy-element lines found in the UV, the optical hydrogen and helium recombination lines' emissivities are strongly dependent on the incident continuum flux, since these lines arise out of excited states whose optical depths depend on the incident flux of photons. Using photoionization calculations, we determine the luminosity-dependent responsivities, ?(r,L(t))=?logLline/?logLcont, of these lines for a general model of the broad emission line region (BLR), with the purpose of establishing them as important probes of the physical conditions within the BLRs of AGNs. The dependence of these lines' emissivities on the incident photon flux invokes a dependence in their responsivities on distance from the central continuum source. In particular, the responsivities of these lines are generally anticorrelated with the incident photon flux. Thus, their responsivities vary with distance within the BLR for a fixed continuum luminosity and change with time as the continuum source varies. Consequently, after correcting for light-travel-time effects, the response of the Balmer and optical helium lines should generally be strongest during low continuum luminosity states. Responsivity that depends on photon flux and continuum state may explain a number of outstanding problems currently under investigation in broad-line variability studies of these and other emission lines. These include the origin of the intrinsic Baldwin effect, measurements of luminosity-dependent lags (a ``breathing'' BLR), and luminosity-dependent variations in integrated broad emission line flux ratios (including He II ?4686/H?), broad-line profile shapes, and radial velocity-dependent intensity ratios. The broad H?/H? and He I/H? flux ratios and the Balmer emission line responsivity are observed to decrease from the line center to the line wings. These, along with our findings, lead to the conclusion that the BLR velocity field diminishes with increasing distance from the central continuum source. This is consistent with recent reverberation studies that find a relationship between the emission-line lag and rms profile width for multiple lines in individual AGNs, which implies that the velocity field is dominated by a central massive object. Finally, the responsivity of ionization-bounded clouds can account for much of the observed behavior of the optical recombination lines (e.g., the weak response of the Balmer line wings) previously attributed to a substantial contribution from matter-bounded clouds at small BLR radii.

Korista, Kirk T.; Goad, Michael R.

2004-05-01

40

Constraints on the outer radius of the broad emission line region of active galactic nuclei  

NASA Astrophysics Data System (ADS)

Here we present observational evidence that the broad emission line region (BELR) of active galactic nuclei (AGN) generally has an outer boundary. This was already clear for sources with an obvious transition between the broad and narrow components of their emission lines. We show that the narrow component of the higher-order Paschen lines is absent in all sources, revealing a broad emission line profile with a broad, flat top. This indicates that the BELR is kinematically separate from the narrow emission line region. We use the virial theorem to estimate the BELR outer radius from the flat top width of the unblended profiles of the strongest Paschen lines, Pa? and Pa?, and find that it scales with the ionizing continuum luminosity roughly as expected from photoionization theory. The value of the incident continuum photon flux resulting from this relationship corresponds to that required for dust sublimation. A flat-topped broad emission line profile is produced by both a spherical gas distribution in orbital motion and an accretion disc wind if the ratio between the BELR outer and inner radius is assumed to be less than ˜100-200. On the other hand, a pure Keplerian disc can be largely excluded, since for most orientations and radial extents of the disc the emission line profile is double-horned.

Landt, Hermine; Ward, Martin J.; Elvis, Martin; Karovska, Margarita

2014-03-01

41

Evidence for Active Galactic Nucleus Feedback in the Broad Absorption Lines and Reddening of Mrk 231  

NASA Astrophysics Data System (ADS)

We present the first J-band spectrum of Mrk 231, which reveals a large He I* ?10830 broad absorption line with a profile similar to that of the well-known Na I broad absorption line. Combining this spectrum with optical and UV spectra from the literature, we show that the unusual reddening noted by Veilleux et al. is explained by a reddening curve like those previously used to explain low values of total-to-selective extinction in Type Ia supernovae. The nuclear starburst may be the origin and location of the dust. Spatially resolved emission in the broad absorption line trough suggests nearly full coverage of the continuum emission region. The broad absorption lines reveal higher velocities in the He I* lines (produced in the quasar-photoionized H II region) compared with the Na I and Ca II lines (produced in the corresponding partially ionized zone). Cloudy simulations show that a density increase is required between the H II and partially ionized zones to produce ionic column densities consistent with the optical and IR absorption line measurements and limits, and that the absorber lies ~100 pc from the central engine. These results suggest that the He I* lines are produced in an ordinary quasar BAL wind that impacts upon, compresses, and accelerates the nuclear starburst's dusty effluent (feedback in action), and the Ca II and Na I lines are produced in this dusty accelerated gas. This unusual circumstance explains the rarity of Na I absorption lines; without the compression along our line of sight, Mrk 231 would appear as an ordinary iron low-ionization, broad absorption line quasar.

Leighly, Karen M.; Terndrup, Donald M.; Baron, Eddie; Lucy, Adrian B.; Dietrich, Matthias; Gallagher, Sarah C.

2014-06-01

42

SDSS 0956+5128: A BROAD-LINE QUASAR WITH EXTREME VELOCITY OFFSETS  

SciTech Connect

We report on the discovery of a Type 1 quasar, SDSS 0956+5128, with a surprising combination of extreme velocity offsets. SDSS 0956+5128 is a broad-lined quasar exhibiting emission lines at three substantially different redshifts: a systemic redshift of z {approx} 0.714 based on narrow emission lines, a broad Mg II emission line centered 1200 km s{sup -1} bluer than the systemic velocity, at z {approx} 0.707, and broad H{alpha} and H{beta} emission lines centered at z {approx} 0.690. The Balmer line peaks are 4100 km s{sup -1} bluer than the systemic redshift. There are no previously known objects with such an extreme difference between broad Mg II and broad Balmer emission. The two most promising explanations are either an extreme disk emitter or a high-velocity black hole recoil. However, neither explanation appears able to explain all of the observed features of SDSS 0956+5128, so the object may provide a challenge to our general understanding of quasar physics.

Steinhardt, Charles L.; Schramm, Malte; Silverman, John D. [Kavli IPMU, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa-shi, Chiba (Japan); Alexandroff, Rachael; Pattarakijwanich, Petchara; Strauss, Michael A. [Department of Astrophysical Sciences, Princeton University, Ivy Lane, Princeton, NJ 08544 (United States); Capak, Peter [California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Civano, Francesca; Elvis, Martin [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Masters, Dan; Mobasher, Bahram [Department of Physics and Astronomy, University of California, Riverside, CA 92508 (United States)

2012-11-01

43

Unusual Broad Absorption Line Quasars from the Sloan Digital Sky Survey  

Microsoft Academic Search

The Sloan Digital Sky Survey has confirmed the existence of populations of broad absorption line (BAL) quasars with various unusual properties. We present and discuss 23 such objects and consider the implications of their wide range of properties for models of BAL outflows and quasars in general. We have discovered one BAL quasar with a record number of absorption lines.

Patrick B. Hall; Scott F. Anderson; Donald G. York; Gordon T. Richards; Xiaohui Fan; Donald P. Schneider; Daniel E. Vanden Berk; T. R. Geballe; Amanda E. Bauer; Robert H. Becker; Marc Davis; Hans-Walter Rix; Hans-Walter Rix; J. Brinkmann; Robert Brunner; A. J. Connolly; István Csabai; Mamoru Doi; James E. Gunn; Zoltan Haiman; Michael Harvanek; G. S. Hennessy; Naohisa Inada; Zeljko Ivezic; David Johnston; S. Kleinman; Julian H. Krolik; Jurek Krzesinski; Peter Z. Kunszt; D. Q. Lamb; Daniel C. Long; Robert H. Lupton; Gajus Miknaitis; Vijay K. Narayanan; Eric Neilsen; P. R. Newman; Atsuko Nitta; Sadanori Okamura; Laura Pentericci; Jeffrey R. Pier; David J. Schlegel; S. Snedden; Alexander S. Szalay; Anirudda R. Thakar; Zlatan Tsvetanov; Richard L. White; Wei Zheng

2002-01-01

44

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

45

Outflows driven by cosmic-ray pressure in broad absorption line QSOs  

NASA Technical Reports Server (NTRS)

It is shown how the escape of ultrarelativistic neutrons from the central engine of an AGN can lead to the production of a strong fast wind with most of the acceleration occurring outside the broad emission line region. This feature is required in order to explain observations of broad absorption line (BAL) QSOs, in which the blue wings of the broad emission lines are often absorbed. The dynamical and thermal structure of the wind is determined, and the formation of BALs in such an outflow is modeled, deriving line profiles and constraining the rate at which the energy or relativistic protons has be be converted to thermal energy in order to provide pressure confinement for the BAL clouds. The problem of acceleration and survival of the clouds is discussed.

Begelman, Mitchell; De Kool, Martijn; Sikora, Marek

1991-01-01

46

The Density of the Broad-Line Emission Region in SEYFERT-1 Galaxies  

NASA Astrophysics Data System (ADS)

One of the characteristics of Seyfert 1 nuclei and quasars is the presence in their spectrum of broad permitted Iines or broad wings to the permitted lines. The forbidden lines show no such wings. Because broad He I and He Illines appear in the spectra of quasars and Seyfert 1 galaxies, it seems very likely that ions such as 0+, 0++ or Ne" actually do exist in the broad-line region and that the forbidden lines are suppressed by collisional de-excitation in a region with electron densities Ne > 107 -10+8 cm-3 (Souffrin, 1969, Astronomy and Astrophysics, 1, 305; Anderson 1970, Astrophysical Journal, 162, 743). Some class 1 Seyfert 1 galaxies and low redshift quasars exhibit an anomalously strong Hel A 5876 Aline; this has been believed to show an unusually large helium-to-hydrogen abundance ratio; however, in a high-density nebula, the He I triplet line intensities are significantly enhanced by electron collisional excitation. Theoretical and observational evidence shows that the gas which gives rise to the broad He Ilines is characterized by Ne- 5 x 109 cm -3 and T - 15,000°Kwith normal abundance (Netzer 1978, Ap. J, 219,822; Feldman and MacAlpine 1978, Ap. J, 221, 486).

Veron, M. P.; Veron, P.

1980-12-01

47

The HST view of the broad line region in low luminosity AGN  

NASA Astrophysics Data System (ADS)

We analyze the properties of the broad line region (BLR) in low luminosity AGN by using HST/STIS spectra. We consider a sample of 24 nearby galaxies in which the presence of a BLR has been reported from their Palomar ground-based spectra. Following a widely used strategy, we used the [S II] doublet to subtract the contribution of the narrow emission lines to the H?+[N II] complex and to isolate the BLR emission. Significant residuals that suggest a BLR, are present. However, the results change substantially when the [O I] doublet is used. Furthermore, the spectra are also reproduced well by just including a wing in the narrow H? and [N II] lines, thus not requiring the presence of a BLR. We conclude that the complex structure of the narrow line region (NLR) is not captured with this approach and that it does not lead to general robust constraints on the properties of the BLR in these low-luminosity AGN. Nonetheless, the existence of a BLR is firmly established in 10 objects, 5 Seyferts, and 5 LINERs. However, the measured BLR fluxes and widths in the 5 LINERs differ substantially with respect to the ground-based data. The BLR sizes in LINERs, which are estimated by using the virial formula from the line widths and the black hole mass, are clustered between ~500 and 2000 Schwarzschild radii (i.e., ~5-100 light days). These values are ~1 order of magnitude greater than the extrapolation to low luminosities of the relation between the BLR radius and AGN luminosity observed in more powerful active nuclei. We found BLR in objects with Eddington ratios as low as Lbol/LEdd ~ 10-5, with the faintest BLR having a luminosity of ~1038erg s-1. This contrasts with theoretical models that predict the BLR disappearance at low luminosity. We ascribe the larger BLR radius to the lower accretion rate in LINERs when compared to the Seyfert, which causes the formation of an inner region dominated by an advection-dominated accretion flow (ADAF). The estimated BLR sizes in LINERs are comparable to the radius where the transition between the ADAF and the standard thin disk occurs due to disk evaporation. We suggest that BLR clouds cannot coexist with the hot inner region and that they only form in the correspondence with a thin accretion disk. Appendix A is available in electronic form at http://www.aanda.org

Balmaverde, B.; Capetti, A.

2014-03-01

48

Broad absorption-line time variability in the QSO CSO 203  

NASA Technical Reports Server (NTRS)

We present spectroscopy of the BALQSO CSO 203 during four epochs over a 17-month time span. These data show three distinct levels in the broad absorption lines (BALs) of Si IV 1397A and C IV 1549A. We also note possible variations in the N V 1240A and Al III 1857A absorption troughs. A broad-band monitoring effort during this period shows that the continuum level remained constant to within 10 percent. We argue that the triggering mechanism for the absorption-line changes is most likely synchronous with the continuum source photons; however, no correlation with the central source has yet been found. The observed variations are consistent with changes in the ionization level in the broad absorption-line region (BALR). We discuss possible mechanisms for these changes and the implications for the structure of the BALR.

Barlow, Thomas A.; Junkkarinen, Vesa T.; Burbidge, E. M.; Weymann, Ray J.; Morris, Simon L.; Korista, Kirk T.

1992-01-01

49

Disentangling the Circumnuclear Environs of Centaurus A. II. On the Nature of the Broad Absorption Line  

NASA Astrophysics Data System (ADS)

We report on atomic gas (H I) and molecular gas (as traced by CO(2-1)) redshifted absorption features toward the nuclear regions of the closest powerful radio galaxy, Centaurus A (NGC 5128). Our H I observations using the Very Long Baseline Array allow us to discern with unprecedented sub-parsec resolution H I absorption profiles toward different positions along the 21 cm continuum jet in the inner 0farcs3 (or 5.4 pc). In addition, our CO(2-1) data obtained with the Submillimeter Array probe the bulk of the absorbing molecular gas with little contamination by emission, which was not possible with previous CO single-dish observations. We shed light on the physical properties of the gas in the line of sight with these data, emphasizing the still open debate about the nature of the gas that produces the broad absorption line (~55 km s-1). First, the broad H I line is more prominent toward the central and brightest 21 cm continuum component than toward a region along the jet at a distance ~20 mas (or 0.4 pc) further from the nucleus. This indicates that the broad absorption line arises from gas located close to the nucleus, rather than from diffuse and more distant gas. Second, the different velocity components detected in the CO(2-1) absorption spectrum match well with other molecular lines, such as those of HCO+(1-0), except the broad absorption line that is detected in HCO+(1-0) (and most likely related to that of the H I). Dissociation of molecular hydrogen due to the active galactic nucleus seems to be efficient at distances r <~ 10 pc, which might contribute to the depth of the broad H I and molecular lines.

Espada, D.; Peck, A. B.; Matsushita, S.; Sakamoto, K.; Henkel, C.; Iono, D.; Israel, F. P.; Muller, S.; Petitpas, G.; Pihlström, Y.; Taylor, G. B.; Trung, D. V.

2010-09-01

50

The similarity of broad iron lines in X-ray binaries and active galactic nuclei  

NASA Astrophysics Data System (ADS)

We have compared the 2001 XMM-Newton spectra of the stellar mass black hole binary XTE J1650-500 and the active galaxy MCG-6-30-15, focusing on the broad, excess emission features at ˜4-7 keV displayed by both sources. Such features are frequently observed in both low-mass X-ray binaries and active galactic nuclei (AGN). For the former case it is generally accepted that the excess arises due to iron emission, but there is some controversy over whether their width is partially enhanced by instrumental processes, and hence also over the intrinsic broadening mechanism. Meanwhile, in the latter case, the origin of this feature is still subject to debate; physically motivated reflection and absorption interpretations are both able to reproduce the observed spectra. In this work we make use of the contemporaneous BeppoSAX data to demonstrate that the breadth of the excess observed in XTE J1650-500 is astrophysical rather than instrumental, and proceed to highlight the similarity of the excesses present in this source and MCG-6-30-15. Both optically thick accretion discs and optically thin coronae, which in combination naturally give rise to relativistically broadened iron lines when the disc extends close to the black hole, are commonly observed in both classes of object. The simplest solution is that the broad emission features present arise from a common process, which we argue must be reflection from the inner regions of an accretion disc around a rapidly rotating black hole; for XTE J1650-500 we find spin constraints of 0.84 ?a*? 0.98 at the 90 per cent confidence level. Other interpretations proposed for AGN add potentially unnecessary complexities to the theoretical framework of accretion in strong gravity.

Walton, D. J.; Reis, R. C.; Cackett, E. M.; Fabian, A. C.; Miller, J. M.

2012-05-01

51

Extinction in low-ionization broad absorption line quasi-stellar objects  

Microsoft Academic Search

Recently, Weymann et al. (1991) presented composite spectra of broad absorption line (BAL) QSOs as divided into two classes, those with spectra containing absorption from both high and low-ionization ionic species, and those showing only high-ionization absorption troughs. They showed that the spectral properties of the former class differed from those of the latter in that their spectra contain stronger

David Sprayberry; Craig B. Foltz

1992-01-01

52

Time Variation of the Broad H? Emission Line in Local Active Galaxies  

NASA Astrophysics Data System (ADS)

High-quality Keck/LRIS long-slit spectra for a sample of 97 Type 1 local active galaxies selected from the Sloan Digital Sky Survey (0.02 ? z ? 0.1; MBH ?107 M?) are used to study the relations between black hole mass (MBH) and host-galaxy properties. Of these objects, eight were found to be lacking broad H? emission lines previously observed in SDSS spectra. Based on seeing and PSF profile, we can exclude the lack of broad lines in the Keck spectra as being due to a telescope pointing error, missing the central AGN. These AGNs are classified as type 1 or type 1.5 Seyferts according to the characteristic presence of broad lines in SDSS spectra, and as 1.8 or 1.9 Seyferts in Keck spectra. We discuss various explanations for this transition including time variation of the torus, time variation of the broad line region, and galaxy mergers resulting in an AGN off-center from the host-galaxy nucleus (including the possibility of a gravitational recoil). Follow up observations at Lick Observatory are used to constrain the different scenarios.

Scott, Bryan; Bennert, V.; Komossa, S.; Treu, T.; Auger, M.; Malkan, M. A.

2014-01-01

53

Broad-line region structure and kinematics in the radio galaxy 3C 120  

NASA Astrophysics Data System (ADS)

Context. Broad emission lines originate in the surroundings of supermassive black holes in the centers of active galactic nuclei (AGN). These broad-line emitting regions are spatially unresolved even for the nearest AGN. The origin and geometry of broad-line region (BLR) gas and their connection with geometrically thin or thick accretion disks is of fundamental importance for the understanding of AGN activity. Aims: One method to investigate the extent, structure, and kinematics of the BLR is to study the continuum and line profile variability in AGN. We selected the radio-loud Seyfert 1 galaxy 3C 120 as a target for this study. Methods: We took spectra with a high signal-to-noise ratio of 3C 120 with the 9.2 m Hobby-Eberly Telescope between Sept. 2008 and March 2009. In parallel, we photometrically monitored the continuum flux at the Wise observatory. We analyzed the continuum and line profile variations in detail (1D and 2D reverberation mapping) and modeled the geometry of the line-emitting regions based on the line profiles. Results: We show that the BLR in 3C 120 is stratified with respect to the distance of the line-emitting regions from the center with respect to the line widths (FWHM) of the rms profiles and with respect to the variability amplitude of the emission lines. The emission line wings of H? and H? respond much faster than their central region. This is explained by accretion disk models. In addition, these lines show a stronger response in the red wings. However, the velocity-delay maps of the helium lines show a stronger response in the blue wing. Furthermore, the He ii ?4686 line responds faster in the blue wing in contradiction to observations made one and a half years later when the galaxy was in a lower state. The faster response in the blue wing is an indication for central outflow motions when this galaxy was in a bright state during our observations. The vertical BLR structure in 3C 120 coincides with that of other AGN. We confirm the general trend: the emission lines of narrow line AGN originate at larger distances from the midplane than AGN with broader emission lines. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, the Ludwig-Maximilians-Universität München, and the Georg-August-Universität Göttingen.Tables 1, 2, 4, 5 are available in electronic form at http://www.aanda.org

Kollatschny, W.; Ulbrich, K.; Zetzl, M.; Kaspi, S.; Haas, M.

2014-06-01

54

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

55

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

56

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

57

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

58

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

59

Evidence for a Broad Relativistic Iron Line from the Neutron Star LMXB Ser X-1  

NASA Technical Reports Server (NTRS)

We report on an analysis of XMM-Newton data from the neutron star low mass X-ray binary (LMXB) Serpens X-1 (Ser X-1). Spectral analysis of EPIC PN data indicates that the previously known broad iron Ka emission line in this source has a significantly skewed structure with a moderately extended red wing. The asymmetric shape of the line is well described with the laor and diskline models in XSPEC, which strongly supports an inner accretion disk origin of the line. To our knowledge this is the first strong evidence for a relativistic line in a neutron star LMXB. This finding suggests that the broad lines seen in other neutron star LMXBs likely originate from the inner disk as well. Detailed study of such lines opens up a new way to probe neutron star parameters and their strong gravitational fields. The laor model describes the line from Ser X-1 somewhat better than diskline, and suggests that the inner accretion disk radius is less than 6GM/c(exp 2). This is consistent with the weak magnetic fields of LMXBs, and may point towards a high compactness and rapid spin of the neutron star. Finally, the inferred source inclination angle in the approximate range 50-60 deg is consistent with the lack of dipping from Ser X-1.

Bhattacharyya, Sudip; Strohmayer, Tod E.

2007-01-01

60

X-Ray Absorption in Type II Quasars: Implications for the Equatorial Paradigm of Broad Absorption Line Quasars  

Microsoft Academic Search

In this article, the hydrogen column densities derived from X-ray observations of type II (hidden) quasars and broad absorption line quasars (BALQSOs) are compared. These column densities represent the amount of absorbing material between the X-ray source and the observer. A sample of type II QSOs with strong narrow emission lines, weak UV continuum and no broad emission lines that

Brian Punsly

2006-01-01

61

Low-ionization lines in the Broad Line Region of Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

Near-infrared spectroscopy is used to study the physical conditions and excitation mechanisms of the low-ionization species such as FeII and OI, emitted by the BLR. Primary cascade lines of FeII arising from the decay of upper levels pumped by Ly-alpha fluorescence are resolved and identified, for the first time, in AGNs. We show that the FeII lines located at 0.999, 1.050, 1.086 and 1.112 microns are the strongest FeII lines in the 0.8-2.4 micron interval. A combination of Ly-alpha fluorescence and collisional excitation are found to be the main contributors. For OI, we found that contrary to the general believed, Ly-beta fluorescence is not the dominant mechanism responsible for the formation of its permitted lines.

Rodríguez-Ardila, A.; Viegas, S. M.; Pastoriza, M.

62

Variability of the broad absorption lines in the QSO UM 232  

NASA Technical Reports Server (NTRS)

Low-resolution spectra of UM 232 taken in 1978, 1979, and 1988 at Lick Observatory are presented. Large changes in the Si IV lambda 1397, CIV lambda 1549, and Al III lambda 1857 broad absorption lines are apparent. The decrease in column density in all three ions and an observed brightening of the QSO suggests that these changes are due to an increase in the ionization level driven by an increase in the central source luminosity. This mechanism has been proposed by Smith and Penston to explain small changes in the absorption spectrum of the QSO 1246-057. The spectra of UM 232 show that the fractional decrease in optical depth is smaller at higher outflow velocies. The structure of the broad absorption-line region (BALR) is investigted by estimating an ionization parameter for each ion species as a function of velocity.

Barlow, Thomas A.; Junkkarinen, Vesa T.; Burbidge, E. Margaret

1989-01-01

63

The Size, Structure and Ionization of the Broad Line Region in NGC 3227  

NASA Astrophysics Data System (ADS)

Hubble Space Telescope spectroscopy of the Seyfert 1.5 galaxy, NGC 3227, confirms previous reports that the broad H? emission line flux is time variable, decreasing by a modest ~ 11% between 1999 and 2000 in response to a corresponding ~ 37% decrease in the underlying continuum. Modeling the gas distribution responsible for the broad H?, H? and H? emission lines favors a spherically symmetric inflow as opposed to a thin disk. Adopting a central black hole mass of 7.6 x 106 M?, determined from prior reverberation mapping, leads to the following dimensions for the size of the region emitting the broad H? line; an outer radius ~ 90 l.d and an inner radius ~ 3 l.d. Thus, the previously determined reverberation size for the broad line region (BLR) consistently coincides with the inner radius of a much larger volume of ionized gas. However, the perceived size of the BLR is an illusion, a consequence of the fact that the emitting region is ionization bounded at the outer radius and diminished by Doppler broadening at the inner radius. The actual dimensions of the inflow remain to be determined. Nevertheless, the steady state mass inflow rate is estimated to be ~10-2 M?/yr which is sufficient to explain the X-ray luminosity of the AGN in terms of radiatively inefficient accretion. Collectively, the results challenge many preconceived notions concerning the nature of BLRs in active galactic nuclei. 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.

2013-01-01

64

Multidimensional laser cooling of broad- and narrow-line 01 dipole transitions  

Microsoft Academic Search

We present a detailed study of laser cooling of neutral atoms with an electric-dipole transition between a Jg=0 ground state and a Je=1 excited state, for both broad- and narrow-line transitions. We focus on the novel effects arising from the multidimensional nature of the laser configuration and point out under which conditions these features can be observed in practice. Our

Daniel J. Phalen; Colin C. Young; Su Yi; Han Pu

2005-01-01

65

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

NASA Technical Reports Server (NTRS)

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 a large spatial extent (not less than 500 pc) centered on the nebula. Several mechanisms for broadening nebular lines are explored: stellar winds, Thomson scattering by hot gas, supernova remnants, and superbubble blowout. All mechanisms have problems. Superbubble blowout, which is the only known mechanism capable of accelerating interstellar gas over such a volume of space, does not appear consistent with the physical properties of the H II region NGC 2363 or with the nature of the host galaxy. It is concluded that the broad nebular lines are probably due to very high velocity gas whose origin is, at present, unknown.

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

1992-01-01

66

The broad emission line and continuum variations of Seyfert galaxies. I - Time scales and amplitudes  

NASA Technical Reports Server (NTRS)

Spectroscopic observations of 13 Seyfert 1 galaxies made from 1979 to 1984 at Palomar and Steward Observatories were analyzed for Balmer-line and optical continuum variability. The majority of the galaxies showed significant variations, particularly in the continuum. Typical peak-to-peak changes for H-beta and H-gamma integrated line fluxes were 100-200 percent, while the continua varied by 200-350 percent. In several cases, Balmer-line and continuum variations were found to be strongly correlated, as expected for photoionization by a central continuum source. However, these correlations were found to be highly nonlinear. Significant correlations were found between variability amplitude and global AGN properties such as luminosity. Moreover, a significant number of variations occurring on short time scales constrains the size of the broad-line region in Seyfert galaxies to about 90 lt-days across or less.

Rosenblatt, Edward I.; Malkan, Matthew A.; Sargent, Wallace L. W.; Readhead, Anthony C. S.

1992-01-01

67

A transition mass for black holes to show broad emission lines  

NASA Astrophysics Data System (ADS)

Although the supermassive (AGN) and stellar mass (BHBs) black holes have many properties in common, the broad emission lines (BELs) are exclusively signatures of the active galactic nuclei (AGN). Based on the detection of these lines from Sloan Digital Sky Survey (SDSS) data bases, there seems to be no AGN with mass MBH ? 105 M?. In this paper, we investigate if such low-mass black holes are really non-existent or they are undetected because the BELs in them are not produced efficiently. Using the ionizing spectral energy distribution for a wide range of black hole mass, 10-109 M?, spanning black hole X-ray binaries (BHBs) to AGN, we calculate the equivalent widths (EWs) of ultraviolet and optical lines Ly? 1216 Å, H? 4861 Å, C IV 1549 Å and Mg II 2798 Å. The LOC (locally optimally emitting cloud) model has been used to describe the broad emission-line region (BELR) for the calculations. We find that the hardening of the SED shape with decreasing mass do not decrease the BEL EWs. However, finite size of the BELR, as measured by the line widths, which is controlled by the mass of the black hole, regulates the production of these emission lines. There seems to be a peak in the EWs of the emission lines for typical AGN black holes of ˜108 M?, below which the lines become intrinsically fainter with a sharp fall-off below ˜106 M?. This may be the cause of the absence of low-mass AGN in SDSS.

Chakravorty, Susmita; Elvis, Martin; Ferland, Gary

2014-01-01

68

Broad-line region kinematics and black hole mass in Markarian 6  

NASA Astrophysics Data System (ADS)

We present the results of optical spectral and photometric observations of the nucleus of Markarian 6 made with the 2.6-m Shajn telescope at the Crimean Astrophysical Observatory. The continuum and emission Balmer-line intensities varied by more than a factor of two during 1992-2008. The lag between the continuum and H? emission-line flux variations is 21.1 ± 1.9 days. For the H? line the lag is about 27 days, but its uncertainty is much larger. We use Monte Carlo simulations of random time series to check the effect of our data sampling on the lag uncertainties and we compare our simulation results with those obtained by the random subset selection (RSS) method of Peterson et al. The lags in the high-velocity wings are shorter than those in the line core in accordance with virial motion. However, the lag is slightly larger in the blue wing than in the red wing. This is a signature of infall gas motion. Probably the broad-line region kinematic in the Mrk 6 nucleus is a combination of Keplerian and infall motions. The velocity-delay dependence is similar for individual observational seasons. Measurements of the H? line width in combination with the reverberation lag permit us to determine the black hole mass, MBH = (1.8 ± 0.2) × 108 M?. This result is consistent with active galactic nucleus scaling relationships between the broad-line region radius and the optical continuum luminosity (RBLR ? L0.5) as well as with the black hole mass-luminosity relationship (MBH-L) under an Eddington luminosity ratio for Mrk 6 of Lbol/LEdd ˜ 0.01.

Doroshenko, V. T.; Sergeev, S. G.; Klimanov, S. A.; Pronik, V. I.; Efimov, Yu. S.

2012-10-01

69

Modeling the double-trough structure observed in broad absorption line QSOs using radiative acceleration  

NASA Astrophysics Data System (ADS)

We present a model explaining the double trough, separated by delta v approximately = 5900 km/s, observed in the C IV lambda-1549 broad absorption line (BAL) in a number of BALQSOs. The model is based on radiative acceleration of the BAL outflow, and the troughs result from modulations in the radiative force. Specifically, where the strong flux from the Lyman-alpha lambda-1215 broad emission line is redshifted to the frequency of the N V lambda-1240 resonance line, in the rest frame of the accelerating N V ions, the acceleration increases and the absorption is reduced. At higher velocities the Lyman-alpha emission is redshifted out of the resonance and the N V ions experience a declining flux which causes the second absorption trough. A strongly nonlinear relationship between changes in the flux and the optical depth in the lines is shown to amplify the expected effect. This model produces double troughs for which the shallowest absorption between the two troughs occurs at v approximately = 5900 km/s. Indeed, we find that a substantial number of the observed objects show this feature. A prediction of the model is that all BALQSOs that show a double-trough signature will be found to have an intrinsic sharp drop in their spectra shortward of approximately 1200 A.

Arav, Nahum; Begelman, Mitchell C.

1994-10-01

70

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

71

The Broad Line Region in AGNs: Structure, Physics, and the f Factor  

NASA Astrophysics Data System (ADS)

We present recent results in an effort to investigate the structure of the broad line region in active galactic nuclei (AGNs) using reverberation mapping data. AGNs provide our only means for exploring the black hole (BH) population outside the local universe. To measure black hole masses (MBH) in AGNs, we use the broad line region (BLR) by assuming that the motion of the emitting gas is dominated by the gravity of the BH. Virial MBH measurements can be made using the resulting Doppler-broadened emission lines: MBH = fR?V^2/G. R is the distance of the emitting gas from the BH, ?V is the velocity dispersion of the emitting gas, obtained from the width of the emission line, and f is a dimensionless factor that accounts for the geometry and orientation of the BLR. Because the BLR is unresolvable, the true value of f in for each object is unknown. Typically, an average virial factor f is used, calculated by assuming that AGNs follow the same MBH--? relation as quiescent galaxies. Our inability to directly observe the structure of the BLR and is a major source of uncertainties in MBH measurements. To learn about BLR structure, we must rely on either reverberation mapping techniques or microlensing of gravitationally lensed quasars. We have been working on various aspects of this problem using high-quality reverberation-mapping data from various observing campaigns based at MDM Observatory on Kitt Peak. Results from these reverberation efforts have a broad impact on our understanding of AGN physics as well as on all MBH measurements in AGNs that provide a basis for galaxy evolution and AGN feedback models.

Grier, Catherine; Peterson, B. M.; Martini, P.; Pogge, R. W.; Pancoast, A.; Treu, T.; Watson, L. C.

2014-01-01

72

XMM-Newton observations of GX 13 + 1: correlation between photoionised absorption and broad line emission  

NASA Astrophysics Data System (ADS)

We analysed data from five XMM-Newton observations of GX 13 + 1 to investigate the variability of the photo-ionised absorber in this source. We fitted EPIC and RGS spectra obtained from the "least-variable" intervals with a model consisting of disc-blackbody and blackbody components together with a Gaussian emission feature at ~6.55-6.7 keV modified by absorption due to cold and photo-ionised material. We found a significant correlation between the hard, ~6-10 keV, flux, the ionisation and column density of the absorber and the equivalent width of the broad iron line. We interpret the correlation in a scenario in which a disc wind is thermally driven at large, ~1010 cm, radii and the broad line results from reprocessed emission in the wind and/or hot atmosphere. The breadth of the emission line is naturally explained by a combination of scattering, recombination and fluorescence processes. We attribute the variations in the absorption and emission along the orbital period to the view of different parts of the wind, possibly located at slightly different inclination angles. We constrain the inclination of GX 13 + 1 to be between 60 and 80° from the strong absorption in the line of sight, which obscures up to 80% of the total emission in one observation, and the absence of eclipses. We conclude that either a disc wind and/or a hot atmosphere can explain the current observations of narrow absorption and broad iron emission features in neutron star low-mass X-ray binaries as a class.

Díaz Trigo, M.; Sidoli, L.; Boirin, L.; Parmar, A. N.

2012-07-01

73

Radiatively driven winds for different power law spectra. [for explaining narrow and broad quasar absorption lines  

NASA Technical Reports Server (NTRS)

The analytic solutions for radiatively driven winds are given for the case in which the winds are driven by absorption of line and continuum radiation. The wind solutions are analytically estimated for different parameters of the central source and for different power law spectra. For flat spectra, three sonic points can exist; it is shown, however, that only one of these sonic points is physically realistic. Parameters of the central source are given which generate winds of further interest for explaining the narrow and broad absorption lines in quasars. For the quasar model presented here, winds which could give rise to the narrow absorption lines are generated by central sources with parameters which are not realistic for quasars.

Beltrametti, M.

1980-01-01

74

Variable Broad Absorption-Lines in the QSO H 0846+1540  

NASA Astrophysics Data System (ADS)

We present spectroscopy of the QSO H 0846+1540 (zem =~ 2.91, V =~ 18.1) over a three year period. These data show significant decreases in two broad absorption-lines (BALs) at moderate and high outflow velocities (9,000 and 26,000 km/sec). The strongest changes are evident in the CIV lambda 1549 lines, but some indication of change is also present in the high outflow velocity NV lambda 1240 BAL. The large decreases in the originally weak BALs in this object, tend to change its appearance from that of a marginal BALQSO to a non-BALQSO. An apparently coincident increase in the continuum level of about 20% accompanies the decrease in absorption strength. The data also show a decrease in the equivalent widths of the CIV, SiIV/OIV] lambda 1400, and NV emission lines. This decrease in emission line equivalent widths is consistent with the observed continuum level increase, if we assume a constant emission line flux. This is the third QSO found to show large BAL changes as part of a four year project of both spectroscopic and broadband imaging observations aimed at identifying time variable BALs in QSOs. The other two QSOs are UM232 (Ap.J. 347,674) and CSO203 (Ap.J. 397,81). About 20 BALQSOs have been monitored spectroscopically and about 60 with broadband imaging. Since BAL changes can occur without any significant (<10%) continuum level change, our study shows that about 15% (3/20) of BALQSOs readily show large broad absorption-line variability when monitored spectroscopically over a few year time scale. This work has been supported by NASA NAS 5-29293 and NAG 5-1630.

Barlow, T. A.; Junkkarinen, V. T.; Burbidge, E. M.

1992-12-01

75

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

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

A polar+equatorial wind model for broad absorption line quasars. I. Fitting the C IV BAL profiles  

NASA Astrophysics Data System (ADS)

Context. Despite all the studies, the geometry of the wind at the origin of the blueshifted broad absorption lines (BAL) observed in nearly 20% of quasars still remains a matter of debate. Aims: We want to see if a two-component polar+equatorial wind geometry can reproduce the typical BAL profiles observed in these objects. Methods: We built a Monte Carlo radiative transfer code (called MCRT) to simulate the line profiles formed in a polar+equatorial wind in which the photons, emitted from a spherically symmetric core are resonantly scattered. Our goal is to reproduce typical C iv line profiles observed in BAL quasars and to identify the parameters governing the line profiles. Results: The two-component wind model appears to be efficient in reproducing the BAL profiles from the P Cygni-type profiles to the more complex ones. Some profiles can also be reproduced with a pole-on view. Our simulations provide evidence of a high-velocity rotation of the wind around the polar axis in BAL quasars with non P Cygni-type line profiles.

Borguet, B.; Hutsemékers, D.

2010-06-01

78

A variable flow as the underpinning of broad absorption lines in quasi-stellar objects  

NASA Astrophysics Data System (ADS)

It is suggested that the salient features of the velocity structure underlying the broad absorption lines of some quasars (BAL QSOs) are produced in a time-variable, freely expanding wind. The observed span in velocities of absorbing elements is produced by time variations in the ejection speed of the gas and not by acceleration of the gas in the absorption region, as must be the case in steady state models. Such a wind is characterized by time-dependent mass injection and energy injection rates.

Braun, Erez; Milgrom, Mordehai

1990-02-01

79

PHOTOMETRIC REVERBERATION MAPPING OF THE BROAD EMISSION LINE REGION IN QUASARS  

SciTech Connect

A method is proposed for measuring the size of the broad emission line region (BLR) in quasars using broadband photometric data. A feasibility study, based on numerical simulations, points to the advantages and pitfalls associated with this approach. The method is applied to a subset of the Palomar-Green quasar sample for which independent BLR size measurements are available. An agreement is found between the results of the photometric method and the spectroscopic reverberation mapping technique. Implications for the measurement of BLR sizes and black hole masses for numerous quasars in the era of large surveys are discussed.

Chelouche, Doron [Department of Physics, Faculty of Natural Sciences, University of Haifa, Haifa 31905 (Israel); Daniel, Eliran, E-mail: doron@sci.haifa.ac.il, E-mail: elirandviv@gmail.com [Department of Physics, Technion, Haifa 32000 (Israel)

2012-03-01

80

Infrared and Optical Properties of Low-z Low-Ionization Broad Absorption Line QSOs  

NASA Astrophysics Data System (ADS)

Observations at low redshift indicate that low-ionization Broad Absorption Line (LoBAL) QSOs may be exclusively associated with recent starbursts, major mergers, and extreme infrared luminosities, suggesting that these objects represent an early stage in the life of QSOs when the AGN is casting out the obscuring dust and gas via outflows. We are testing this hypothesis by conducting a systematic study of a volume-limited sample of 22 LoBALs drawn from the SDSS DR3 within 0.5 < z < 0.6. We present preliminary results from Spitzer MIPS observations and highlight some optical spectral properties.

Lazarova, M. S.; Canalizo, G.

2009-10-01

81

Study of transmission line attenuation in broad band millimeter wave frequency range.  

PubMed

Broad band millimeter wave transmission lines are used in fusion plasma diagnostics such as electron cyclotron emission (ECE), electron cyclotron absorption, reflectometry and interferometry systems. In particular, the ECE diagnostic for ITER will require efficient transmission over an ultra wide band, 100 to 1000 GHz. A circular corrugated waveguide transmission line is a prospective candidate to transmit such wide band with low attenuation. To evaluate this system, experiments of transmission line attenuation were performed and compared with theoretical loss calculations. A millimeter wave Michelson interferometer and a liquid nitrogen black body source are used to perform all the experiments. Atmospheric water vapor lines and continuum absorption within this band are reported. Ohmic attenuation in corrugated waveguide is very low; however, there is Bragg scattering and higher order mode conversion that can cause significant attenuation in this transmission line. The attenuation due to miter bends, gaps, joints, and curvature are estimated. The measured attenuation of 15 m length with seven miter bends and eighteen joints is 1 dB at low frequency (300 GHz) and 10 dB at high frequency (900 GHz), respectively. PMID:24182108

Pandya, Hitesh Kumar B; Austin, M E; Ellis, R F

2013-10-01

82

Study of transmission line attenuation in broad band millimeter wave frequency range  

SciTech Connect

Broad band millimeter wave transmission lines are used in fusion plasma diagnostics such as electron cyclotron emission (ECE), electron cyclotron absorption, reflectometry and interferometry systems. In particular, the ECE diagnostic for ITER will require efficient transmission over an ultra wide band, 100 to 1000 GHz. A circular corrugated waveguide transmission line is a prospective candidate to transmit such wide band with low attenuation. To evaluate this system, experiments of transmission line attenuation were performed and compared with theoretical loss calculations. A millimeter wave Michelson interferometer and a liquid nitrogen black body source are used to perform all the experiments. Atmospheric water vapor lines and continuum absorption within this band are reported. Ohmic attenuation in corrugated waveguide is very low; however, there is Bragg scattering and higher order mode conversion that can cause significant attenuation in this transmission line. The attenuation due to miter bends, gaps, joints, and curvature are estimated. The measured attenuation of 15 m length with seven miter bends and eighteen joints is 1 dB at low frequency (300 GHz) and 10 dB at high frequency (900 GHz), respectively.

Pandya, Hitesh Kumar B. [ITER-India, IPR, Gandhinagar, Gujarat (India)] [ITER-India, IPR, Gandhinagar, Gujarat (India); Austin, M. E. [Institute for Fusion Studies, the University of Texas at Austin, Austin, Texas (United States)] [Institute for Fusion Studies, the University of Texas at Austin, Austin, Texas (United States); Ellis, R. F. [Laboratory for Plasma and Fusion Energy Studies, University of Maryland, College Park, Maryland 20742 (United States)] [Laboratory for Plasma and Fusion Energy Studies, University of Maryland, College Park, Maryland 20742 (United States)

2013-10-15

83

Surprises from a Deep ASCA Spectrum of the Broad Absorption Line Quasar PHL 5200  

NASA Technical Reports Server (NTRS)

We present a deep (approx. 85 ks) ASCA observation of the prototype broad absorption line quasar (BALQSO) PHL 5200. This is the best X-ray spectrum of a BALQSO yet. We find the following: (1) The source is not intrinsically X-ray weak. (2) The line-of-sight absorption is very strong, with N(sub H) = 5 x 10(exp 23)/sq cm. (3) The absorber does not cover the source completely; the covering fraction is approx. 90%. This is consistent with the large optical polarization observed in this source, implying multiple lines of sight. The most surprising result of this observation is that (4) the spectrum of this BALQSO is not exactly similar to other radio-quiet quasars. The hard X-ray spectrum of PHL 5200 is steep, with the power-law spectral index alpha approx. 1.5. This is similar to the steepest hard X-ray slopes observed so far. At low redshifts, such steep slopes are observed in narrow-line Seyfert 1 (NLS1) galaxies, believed to be accreting at a high Eddington rate. This observation strengthens the analogy between BALQSOs and NLS1 galaxies and supports the hypothesis that BALQSOs represent an early evolutionary state of quasars. It is well accepted that the orientation to the line of sight determines the appearance of a quasar: age seems to play a significant role as well.

Mathur, Smita; Matt, G.; Green, P. J.; Elvis, M.; Singh, K. P.

2002-01-01

84

THE IMPORTANCE OF BROAD EMISSION LINE WIDTHS IN SINGLE-EPOCH BLACK HOLE MASS ESTIMATES  

SciTech Connect

Estimates of the mass of super-massive black holes (BHs) in distant active galactic nuclei (AGNs) can be obtained efficiently only through single-epoch (SE) spectra, using a combination of their broad emission line widths and continuum luminosities. Yet the reliability and accuracy of the method and the resulting mass estimates, M{sub BH}, remain uncertain. A recent study by Croom using a sample of Sloan Digital Sky Survey, 2dF QSO Redshift Survey, and 2dF-SDSS LRG and QSO Survey quasars suggests that line widths contribute little information about the BH mass in these SE estimates and can be replaced by a constant value without significant loss of accuracy. In this Letter, we use a sample of nearby reverberation-mapped AGNs to show that this conclusion is not universally applicable. We use the bulge luminosity (L{sub Bulge}) of these local objects to test how well the known M{sub BH}-L{sub Bulge} correlation is recovered when using randomly assigned line widths instead of the measured ones to estimate M{sub BH}. We find that line widths provide significant information about M{sub BH}, and that for this sample, the line width information is just as significant as that provided by the continuum luminosities. We discuss the effects of observational biases upon the analysis of Croom and suggest that the results can probably be explained as a bias of flux-limited, shallow quasar samples.

Assef, R. J. [Jet Propulsion Laboratory, California Institute of Technology, MS 169-530, 4800 Oak Grove Dr., Pasadena, CA 91109 (United States); Frank, S.; Grier, C. J.; Kochanek, C. S.; Peterson, B. M. [Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Denney, K. D., E-mail: roberto.j.assef@jpl.nasa.gov [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen (Denmark)

2012-07-01

85

Discovery of an X-ray Violently Variable Broad Absorption Line Quasar  

NASA Technical Reports Server (NTRS)

In this letter, we report on a quasar that is violently variable in the X-rays, XVV. It is also a broad absorption line quasar (BALQSO) that exhibits both high ionization and low ionization UV absorption lines (LoBALQSO). It is very luminous in the X-rays (approximately 10(exp 46) ergs s(sup -l) over the entire X-ray band). Surprisingly, this does not over ionize the LoBAL outflow. The X-rays vary by a factor of two within minutes in the quasar rest frame, which is shorter than 1/30 of the light travel time across a scale length equal to the black hole radius. We concluded that the X-rays are produced in a relativistic jet beamed toward earth in which variations in the Doppler enhancement produce the XVV behavior.

Ghosh, Kajal K.; Gutierrez, Carlos M.; Punsly, Brian; Chevallier, Loic; Goncalves, Anabela C.

2006-01-01

86

LAMP 2008 and 2011: Dynamical Modeling of the Broad Line Region  

NASA Astrophysics Data System (ADS)

We present dynamical modeling of the broad line region (BLR) using high-quality reverberation mapping data taken as part of the Lick AGN Monitoring Projects 2008 and 2011. While traditional reverberation mapping analysis yields estimates of the mean radius of the BLR, c?, and black hole mass, M = (f v^2 c?)/G, direct modeling of the reverberation mapping data allows us to constrain more detailed features of the BLR. In our geometric and dynamical model, we constrain the shape and inclination angle of the BLR with respect to the observer's line of sight. In addition to geometric constraints, we also obtain an independent estimate of the black hole mass that does not depend upon the normalizing factor, f, required by traditional analysis. By comparing our independent estimate of the black hole mass to the traditional estimate, we can recover the normalizing factor for individual AGNs.

Pancoast, Anna; Brewer, B. J.; Treu, T.; LAMP2008 Collaboration; LAMP2011 Collaboration

2013-01-01

87

Are Proplyds the Low-Energy Counterpart of Clouds Populating the AGNs Broad Line Region?  

NASA Astrophysics Data System (ADS)

The stability of the clouds producing the broadening of permitted lines in A GNs is a challenge for the persistence of these features during the galactic nucleus active fase lifetime. The formation of succesive generations of clouds in this very agressive enviroment, seems not to be the more adequated scenarion to explain this phenomenon. Why should new clouds be formed in regions where the UV radiation is so intense as to destroy the previously existing ones? The discovery of proplyds in Orion and NGC3603, as well as in 30Dor, shows that the formation of stars with protostars with surrounding disk is a common phenomenon in HII regions with very different radiation fields. We discuss that as a mechanism to explain the persistence of the clouds in the AGNs broad line regions.

Dottori, H.

2000-11-01

88

REVERBERATION AND PHOTOIONIZATION ESTIMATES OF THE BROAD-LINE REGION RADIUS IN LOW-z QUASARS  

SciTech Connect

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{sub BH}. The radius of the BLR may be inferred from an extrapolation of the correlation between source luminosity and reverberation-derived r{sub BLR} measures (the so-called Kaspi relation involving about 60 low-z sources). We are exploring a different method for estimating r{sub BLR} directly from inferred physical conditions in the BLR of each source. We report here on a comparison of r{sub 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 A (Al III {lambda}1860/Si III] {lambda}1892, C IV {lambda}1549/Al III {lambda}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{sub BLR} and those from reverberation mapping. We suggest empirical corrections to improve the agreement between individual photoionization-derived r{sub BLR} values and those obtained from reverberation mapping. The results in this paper can be exploited to estimate M{sub 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{beta}, thereby providing a reliable virial broadening estimator that can be measured in large samples of high-z quasars.

Negrete, C. Alenka [Instituto Nacional de Astrofisica, Optica y Electronica (Mexico); Dultzin, Deborah [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico (Mexico); Marziani, Paola [INAF, Astronomical Observatory of Padova, I-35122 Padova (Italy); Sulentic, Jack W., E-mail: cnegrete@inaoep.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)

2013-07-01

89

Quasar broad absorption line variability measurements using reconstructions of unabsorbed spectra  

NASA Astrophysics Data System (ADS)

We present a two-epoch Sloan Digital Sky Survey and Gemini/GMOS+William Herschel Telescope/ISIS variability study of 50 broad absorption line (BAL) quasars of redshift range 1.9 < z < 4.2, containing 38 Si IV and 59 C IV BALs and spanning rest-frame time intervals of ?10 months to 3.7 years. We find that 35/50 quasars exhibit one or more variable BALs, with 58 per cent of Si IV and 46 per cent of C IV BALs showing variability across the entire sample. On average, Si IV BALs show larger fractional change in BAL pseudo-equivalent width than C IV BALs, as referenced to an unabsorbed continuum+emission line spectrum constructed using non-negative matrix factorization. No correlation is found between BAL variability and quasar luminosity, suggesting that ionizing continuum changes do not play a significant role in BAL variability (assuming the gas is in photoionization equilibrium with the ionizing continuum). A subset of 14 quasars have one variable BAL from each of Si IV and C IV with significant overlap in velocity space and for which variations are in the same sense (strengthening or weakening) and which appear to be correlated (98 per cent confidence). We find examples of both appearing and disappearing BALs in weaker/shallower lines with disappearance rates of 2.3 per cent for C IV and 5.3 per cent for Si IV, suggesting average lifetimes of 142 and 43 years, respectively. We identify five objects in which the BAL is coincident with the broad emission line, but appears to cover only the continuum source. Assuming a clumpy inhomogeneous absorber model and a typical size for the continuum source, we infer a maximum cloud radius of 1013 to 1014 cm, assuming Eddington limited accretion.

Wildy, C.; Goad, M. R.; Allen, J. T.

2014-01-01

90

Radiation Pressure-Driven Magnetic Disk Winds in Broad Absorption Line Quasi-Stellar Objects  

NASA Technical Reports Server (NTRS)

We explore a model in which QSO broad absorption lines (BALS) are formed in a radiation pressure-driven wind emerging from a magnetized accretion disk. The magnetic field threading the disk material is dragged by the flow and is compressed by the radiation pressure until it is dynamically important and strong enough to contribute to the confinement of the BAL clouds. We construct a simple self-similar model for such radiatively driven magnetized disk winds, in order to explore their properties. It is found that solutions exist for which the entire magnetized flow is confined to a thin wedge over the surface of the disk. For reasonable values of the mass-loss rate, a typical magnetic field strength such that the magnetic pressure is comparable to the inferred gas pressure in BAL clouds, and a moderate amount of internal soft X-ray absorption, we find that the opening angle of the flow is approximately 0.1 rad, in good agreement with the observed covering factor of the broad absorption line region.

DeKool, Martin; Begelman, Mitchell C.

1995-01-01

91

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

92

An Intrinsic Baldwin Effect in the H Beta Broad Emission Line in the Spectrum of NGC 5548  

NASA Technical Reports Server (NTRS)

We investigate the possibility of an intrinsic Baldwin effect (i.e., nonlinear emission-line response to continuum variations) in the broad HP emission line of the active galaxy NGC 5548 using crosscorrelation techniques to remove light-travel time effects from the data. We find a nonlinear relationship between the HP emission line and continuum fluxes that is in good agreement with theoretical predictions. We suggest that similar analysis of multiple lines might provide a useful diagnostic of physical conditions in the broad-line region.

Gilbert, Karoline M.; Peterson, Bradley M.

2003-01-01

93

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 spectroscopic features would be produced by such “Intervening BLR Clouds” crossing our line of sight to the accretion disk, which is 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. We find that single clouds will have little effect on the optical/UV spectrum because BLR clouds are likely to be much smaller than the accretion disk. 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 FUV 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 AGN. Comparison with observations suggests that the SED of Mrk 766 may be affected by intervening BLR clouds and Intervening BLR Clouds may exist in most of AGNs.

Wang, Ye; Ferland, G. J.; Hu, C.; Wang, J.; Du, P.

2014-01-01

94

Climatic change and the broad-scale distribution of terrestrial ecosystem complexes  

Microsoft Academic Search

The broad-scale distribution of terrestrial ecosystem complexes is determined in large part by climate and can be altered by climatic change due to natural causes or due to human activities such as those leading to increasing atmospheric CO2 concentration. Classifications that recognize the dependence of natural vegetation on climate provide one means of constructing maps to display the impact of

William R. Emanuel; Herman H. Shugart; Mary P. Stevenson

1985-01-01

95

Dramatic X-Ray Spectral Variability of the Broad Absorption Line Quasar PG 2112+059  

NASA Astrophysics Data System (ADS)

With a 1999 ASCA observation, PG 2112+059 became notable as the first broad absorption line (BAL) quasar found to exhibit a typical radio-quiet quasar X-ray continuum underlying a large amount of intrinsic absorption. We present a recent Chandra ACIS-S3 observation of PG 2112+059 that demonstrates remarkable spectral and luminosity variability since that time. In addition to a decrease in the continuum normalization by a factor of ~3.5, the absorption column density has apparently increased substantially, and a strong feature in the Fe K? region has appeared. Concurrent Hubble Space Telescope (HST) STIS data compared with archival HST data from earlier epochs show evidence for variability of the continuum (up to a factor of ~1.7 in the ultraviolet), and in some absorption features of the C IV ?1549 BAL since 1992; however, the O VI BAL structure is consistent with a 1995 observation. We also present evidence for Ly?-O VI ?1037.62 and Ly?-N V ?1242.80 line-locked absorption systems, supporting the assumption that ultraviolet line pressure is driving the BAL outflow. Whereas ultraviolet BALs typically exhibit only modest equivalent width variability over timescales of years, the dramatic X-ray variability of PG 2112+059 suggests that X-ray spectral variability studies of BAL quasars have great potential for probing the physics of quasar winds.

Gallagher, S. C.; Brandt, W. N.; Wills, Beverley J.; Charlton, J. C.; Chartas, G.; Laor, A.

2004-03-01

96

Quasar Cartography: From Black Hole to Broad-line Region Scales  

NASA Astrophysics Data System (ADS)

A generalized approach to reverberation mapping (RM) is presented, which is applicable to broad- and narrowband photometric data, as well as to spectroscopic observations. It is based on multivariate correlation analysis techniques and, in its present implementation, is able to identify reverberating signals across the accretion disk and the broad-line region (BLR) of active galactic nuclei (AGNs). Statistical tests are defined to assess the significance of time-delay measurements using this approach, and the limitations of the adopted formalism are discussed. It is shown how additional constraints on some of the parameters of the problem may be incorporated into the analysis thereby leading to improved results. When applied to a sample of 14 Seyfert 1 galaxies having good-quality high-cadence photometric data, accretion disk scales and BLR sizes are simultaneously determined, on a case-by-case basis, in most objects. The BLR scales deduced here are in good agreement with the findings of independent spectroscopic RM campaigns. Implications for the photometric RM of AGN interiors in the era of large surveys are discussed.

Chelouche, Doron; Zucker, Shay

2013-06-01

97

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

98

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

99

Strong X-Ray Absorption in a Broad Absorption Line Quasar: PHL 5200  

NASA Technical Reports Server (NTRS)

We present ASCA observations of the z=1.98 prototype broad absorption line quasar (BALQSO): PHL 5200. The source detected in both SIS and GIS. A power-law spectrum (alpha(sub epsilon)=0.6(sup 0.9)(sub -0.6)) with large intrinsic absorption (N(sub H)=1.3(sup 2.3)(sub -1.1)x10(exp 23)cm(exp -2)) best describes the spectrum. Excess column density over the local Galactic value is required at the 99% confidence level. This detection suggests that although BALQSOs are X-ray-quiet, it is strong absorption in the BAL region that makes them appear faint to low-energy X-ray experiments. The required intrinsic absorbing column density is 2-3 orders of magnitude larger than earlier estimates of column densities in BALQSOs. This implies that the BAL systems are much more highly ionized than was previously thought.

Mathur, Smita; Elvis, Martin; Singh, K. P.

1995-01-01

100

Strong X-Ray Absorption in a Broad Absorption Line Quasar: PHL 5200  

NASA Technical Reports Server (NTRS)

We present ASCA observations of the z = 1.98 prototype broad absorption line quasar (BALQSO):PHL5200. The source was detected in both SIS and GIS. A power-law spectrum (alpha(sub E) = 0.6(sup +0.9)(sub -0.6) with large intrinsic absorption (N(sub H) = 1.3(sup +2.3)(sub -1.1) x 10(exp 23)/sq cm) best describes the spectrum. Excess column density over the local Galactic value is required at the 99% confidence level. This detection suggests that, although BALQSOs are X-ray-quiet, it is strong absorption in the BAL region that makes them appear faint to low-energy X-ray experiments. The required intrinsic absorbing column density is 2-3 orders of magnitude larger than earlier estimates of column densities in BALQSOs. This implies that the BAL systems are much more highly ionized than was previously thought.

Mathur, Smita; Elvis, Martin; Singh, K. P.

1997-01-01

101

Deep Asca Campaign to Probe one Typical Broad Absorption Line Qso  

NASA Technical Reports Server (NTRS)

We present a deep ASCA observation of a broad absorption line quasar (BALQSO) PG 0946+301. The source was clearly detected in one of the gas imaging spectrometers, but not in any other detector. If BALQSOs have intrinsic X-ray spectra similar to normal radio-quiet quasars, our observations imply that there is Thomson thick X-ray absorption (NH(1024 per square centimeter) toward PG 0946+301. This is the largest column density estimated so far toward a BALQSO. The absorber must be at least partially ionized and may be responsible for attenuation in the optical and UV. If the Thomson optical depth toward BALQSOs is close to 1, as inferred here, then spectroscopy in hard X-rays with large telescopes like XMM would be feasible.

Green, P.

2001-01-01

102

X-ray spectral constraints on the broad-line cloud geometry of NGC 4151  

NASA Technical Reports Server (NTRS)

X-ray spectral data from NGC 4151 taken with the Einstein Solid-State Spectrometer (SSS) and the HEAO-1 A-2 experiment cannot be simply reconciled with absorption from a uniform column of cold gas. The SSS data can, however, be explained in terms of a clumped absorber with approximately 10% uncovered fraction and factor-of-two overabundances in Z equal to or greater than 14 elements relative to solar oxygen. It is shown that these and previously reported spectral and variability data can be quantitatively reconciled with absorption arising in the cold clouds responsible for the broad optical line emission if the cloud dimensions are small compared to the central source size. It is suggested that the lack of significant X-ray absorption observed from much higher luminosity Seyferts and quasars is a natural consequence of our picture for NGC 4151.

Holt, S. S.; Muchotzky, R. F.; Becker, R. H.; Boldt, E. A.; Serlemitsos, P. J.; Szymkowiak, A. E.; White, N. E.

1980-01-01

103

X-ray spectral constraints on the broad-line cloud geometry of NGC 4151  

NASA Technical Reports Server (NTRS)

X-ray spectral data from NGC 4151 taken with the Einstein Solid-State Spectrometer (SSS) and the HEAO 1 A-2 experiment cannot be simply reconciled with absorption from a uniform column of cold gas. The SSS data can, however, be explained in terms of a clumped absorber with approximately 10% uncovered fraction and factor-of-two overabundances in Z equal to or greater than 14 elements relative to solar oxygen. It is shown that these and previously reported spectral and variability data can be quantitatively reconciled with absorption arising in the cold clouds responsible for the broad optical line emission if the cloud dimensions are small compared to the central source size. It is suggested that the lack of significant X-ray absorption observed from much higher luminosity Seyferts and quasars is a natural consequence of the proposed picture for NGC 4151.

Holt, S. S.; Mushotzky, R. F.; Boldt, E. A.; Serlemitsos, P. J.; Becker, R. H.; Szymkowiak, A. E.; White, N. E.

1980-01-01

104

THE INTRINSIC FRACTIONS AND RADIO PROPERTIES OF LOW-IONIZATION BROAD ABSORPTION LINE QUASARS  

SciTech Connect

Low-ionization (Mg II, Fe II, and Fe III) broad absorption line quasars (LoBALs) probe a relatively obscured quasar population and could be at an early evolutionary stage for quasars. We study the intrinsic fractions of LoBALs using the Sloan Digital Sky Survey (SDSS), Two Micron All Sky Survey, and Faint Images of the Radio Sky at Twenty cm survey. We find that the LoBAL fractions of the near-infrared (NIR) and radio samples are approximately 5-7 times higher than those measured in the optical sample. This suggests that the fractions measured in the NIR and radio bands are closer to the intrinsic fractions of the populations, and that the optical fractions are significantly biased due to obscuration effects, similar to high-ionization broad absorption line quasars (HiBALs). Considering a population of obscured quasars that do not enter the SDSS, which could have a much higher LoBAL fraction, we expect that the intrinsic fraction of LoBALs could be even higher. We also find that the LoBAL fractions decrease with increasing radio luminosities, again, similarly to HiBALs. In addition, we find evidence for increasing fractions of LoBALs toward higher NIR luminosities, especially for FeLoBALs with a fraction of {approx}18% at M{sub K{sub s}}< -31 mag. This population of NIR-luminous LoBALs may be at an early evolutionary stage of quasar evolution. To interpret the data, we use a luminosity-dependent model for LoBALs that yields significantly better fits than those from a pure geometric model.

Dai Xinyu [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States); Shankar, Francesco [GEPI, Observatoire de Paris, CNRS, University of Paris Diderot, 5 Place Jules Janssen, F-92195 Meudon (France); Sivakoff, Gregory R., E-mail: xdai@ou.edu [Department of Physics, University of Alberta, Edmonton, AB T6G 2E1 (Canada)

2012-10-01

105

C IV absorption-line variability in X-ray-bright broad absorption-line quasi-stellar objects  

NASA Astrophysics Data System (ADS)

We report the kinematic shift and strength variability of the C IV broad absorption-line (BAL) trough in two high-ionization X-ray-bright quasi-stellar objects (QSOs): SDSS J085551+375752 (at zem ˜ 1.936) and SDSS J091127+055054 (at zem ˜ 2.793). Both these QSOs have shown a combination of profile shifts and the appearance and disappearance of absorption components belonging to a single BAL trough. The observed average kinematic shift of the whole BAL profile resulted in an average deceleration of ˜-0.7 ± 0.1, -2.0 ± 0.1 cm s-2 over rest-frame time-spans of 3.11 and 2.34 yr for SDSS J085551+375752 and SDSS J091127+055054, respectively. To our knowledge, these are the largest kinematic shifts known, exceeding by factors of about 2.8 and 7.8 the highest deceleration reported in the literature; this makes both objects potential candidates to investigate outflows using multiwavelength monitoring of their line and continuum variability. We explore various possible mechanisms to understand the observed profile variations. Outflow models involving many small self-shielded clouds, probably moving in a curved path, provide the simplest explanation for the C IV BAL strength and velocity variations, along with the X-ray-bright nature of these sources.

Joshi, Ravi; Chand, Hum; Srianand, Raghunathan; Majumdar, Jhilik

2014-07-01

106

Complex Periodic Spirals and Line-Defect Turbulence in a Chemical System  

NASA Astrophysics Data System (ADS)

Recent numerical simulations on two-dimensional model reaction-diffusion systems have revealed unusual spiral waves with complex oscillations and turbulent patterns, both mediated by ``line defects.'' Here we report the observation of such patterns in a laboratory experiment for the first time; complex spiral waves with period-2 and period-3 and turbulent patterns filled with a tangle of line defects are observed and their spatiotemporal dynamics are elucidated by line defects. Since line defects are a generic property of complex periodic media, the observed patterns are expected to arise in a broad class of complex periodic systems.

Park, Jin-Sung; Lee, Kyoung J.

1999-12-01

107

On the relationship between jet and broad emission lines variability in Flat Spectrum Radio Quasars  

NASA Astrophysics Data System (ADS)

Studies of the relationship between variations in the jet continuum emission and those of broad emission lines (and disk emission) can provide new clues about the structure of the central regions of jetted AGNs and properties of the outflow, such as the location of the active region. Thanks to Fermi and the large multiwavelength coverage that it stimulated (and supported) high quality data are now available for several blazars and this type of investigation is becoming possible and beginning to bear fruit. Recent results on 3C 454.3 (e.g. by Isler et al. 2013, Leon-Tavares et al. 2012) and other luminous FSRQ (e.g. PKS 1510-089, Isler et al.) reveal a connection between broad emission lines intensity and variations of the jet's non-thermal continuum. This suggests that the latter may be responsible for the line variability, a rather unexpected possibility, poorly explored, though not totally surprising. These new results and data certainly motivate a closer look at the possible (radiative) interplay between jet, accretion and "ambient gas", which is essential to understand observations and draw from them constraints on the geometry and dynamics of the AGN components, such as the location where the jet becomes dissipative. In particular the interpretation of the correlated (or not) variability requires to look more in depth at the relationship between the various "radiative signals", some of which may be responsible for causing variations in other components, examples being BLR radiation seeding inverse Compton emission in the jet, disk emission increasing BLR power, or jet emission ionizing part of the BLR as recently discussed. Because the jet "blob" itself moves nearly at the same speed of the "signals", the actual relationships among observables are somewhat at odds with the naive intuition. I will present results of our study of the observational implications/appearance of variations originating in different components and discuss the implications for the interpretation of recent novel observational work. GF acknowledges support from NNX11AO15G (Fermi GI), NNX12AE43G (NASA/ADAP)

Fossati, Giovanni

2014-01-01

108

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

109

Hubble Space Telescope Faint Object Spectrograph and ground-based observations of the broad absorption line quasar 0226-1024  

NASA Technical Reports Server (NTRS)

Faint Object Spectrograph data from the Hubble Space Telescope of the broad absorption line quasar 0226-1024 have revealed the presence of 8-10 absorbing ions between 680 and 1000 A (restframe): C III, N III, N IV, O III, O IV, O VI, S V, S VI, possibly Ne VIII, and possibly O V* arising from a metastable excited state. We also present ground-based optical observations of the broad line troughs for the following ions: H I, C IV, N V, Si IV, and possibly Fe III, S IV, P V, and C III* (also arising from a metastable excited state). The results of this fit are used to estimate the absorbing ionic column densities. There is evidence that the broad absorption line clouds are optically thick and either do not completely cover the continuum source or narrow unresolved lines are present.

Korista, Kirk T.; Weymann, Ray J.; Morris, Simon L.; Kopko, Michael, Jr.; Turnshek, David A.; Hartig, George F.; Foltz, Craig B.; Burbidge, E. M.; Junkkarinen, Vesa T.

1992-01-01

110

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

111

Radio Properties of Low Redshift Broad Line Active Galactic Nuclei Including Multiple Component Radio Sources  

NASA Astrophysics Data System (ADS)

We present results on the radio properties of a low redshift (z < 0.35) sample of 8434 broad line active galactic nuclei (AGNs) from the Sloan Digital Sky Survey after correlating the optical sources with radio sources in the Faint Images of the Radio Sky at Twenty-Centimeters survey. We find that 10% of our sample has radio emission < 4" away from the optical counterpart (core-only sources), and 1% has significant extended emission that must be taken into account when calculating the total radio luminosity (multi-component sources). Association of the extended radio emission is established by the proximity to the optical source, physical connection of jets and lobes, or large scale symmetry like in classic FRIIs. From these data we find an FRI/FRII luminosity dividing line like that found by Fanaroff & Riley (1974), where we use our core-only sources as proxies for FRIs, and our multi-component sources for the FRIIs. We find a bimodal distribution for the radio loudness (R = L(radio)/L(opt)) where the lower radio luminosity core-only sources appear as a population separate from the multi-component extended sources, compared with no evidence for bimodality when just the core-only sources are used. We also find that a log(R) value of 1.75 is well suited to separate the FRIs from the FRIIs, and that the R bimodality seen here is really a manifestation of the FRI/FRII break originally found by Fanaroff & Riley (1974). We find modest trends in the radio loud fraction as a function of Eddington ratio and black hole mass, where the fraction of RL AGNs decreases with increasing Eddington ratio, and increases when the black hole mass is above 2 x 108 solar masses.

Rafter, Stephen E.

2010-01-01

112

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

113

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

114

Gravitational microlensing of a reverberating quasar broad-line region - I. Method and qualitative results  

NASA Astrophysics Data System (ADS)

The kinematics and morphology of the broad emission-line region (BELR) of quasars are the subject of significant debate. The two leading methods for constraining BELR properties are microlensing and reverberation mapping. Here we combine these two methods with a study of the microlensing behaviour of the BELR in Q2237+0305, as a change in continuum emission (a 'flare') passes through it. Beginning with some generic models of the BELR - sphere, bicones, disc - we slice in velocity and time to produce brightness profiles of the BELR over the duration of the flare. These are numerically microlensed to determine whether microlensing of reverberation mapping provides new information about the properties of BELRs. We describe our method and show images of the models as they are flaring, and the unlensed and lensed spectra that are produced. Qualitative results and a discussion of the spectra are given in this paper, highlighting some effects that could be observed. Our conclusion is that the influence of microlensing, while not strong, can produce significant observable effects that will help in differentiating the properties of BELRs. Research undertaken as part of the Commonwealth Cosmology Initiative (CCI: ), an international collaboration supported by the Australian Research Council.

Garsden, H.; Bate, N. F.; Lewis, G. F.

2011-12-01

115

Neutrino-heated stars and broad-line emission from active galactic nuclei  

NASA Technical Reports Server (NTRS)

Nonthermal radiation from active galactic nuclei indicates the presence of highly relativistic particles. The interaction of these high-energy particles with matter and photons gives rise to a flux of high-energy neutrinos. In this paper, the influence of the expected high neutrino fluxes on the structure and evolution of single, main-sequence stars is investigated. Sequences of models of neutrino-heated stars in thermal equilibrium are presented for masses 0.25, 0.5, 0.8, and 1.0 solar mass. In addition, a set of evolutionary sequences for mass 0.5 solar mass have been computed for different assumed values for the incident neutrino energy flux. It is found that winds driven by the heating due to high-energy particles and hard electromagnetic radiation of the outer layers of neutrino-bloated stars may satisfy the requirements of the model of Kazanas (1989) for the broad-line emission clouds in active galactic nuclei.

Macdonald, James; Stanev, Todor; Biermann, Peter L.

1991-01-01

116

Gamma-Ray Emision from the Broad-Line Radio Galaxy 3C 111  

NASA Technical Reports Server (NTRS)

The broad-line radio galaxy 3C 111 has been suggested as the counterpart of the Gamma-ray source 3EGJ0416+3650. While 3C 111 meets most of the criteria for a high-probability identification, like a bright fla t-spectrum radio core and a blazarlike broadband SED, in the Third EG RET Catalog, the large positional offset of about 1.5 degrees put 3C1 11 outside the 99% probability region for 3EG J0416+3650, making this association questionable. We present a re-analysis of all available data for 3C111 from the EGRET archives, resulting in probable detection of high-energy Gamma-ray emission above 1000MeV from a position clo se to the nominal position of 3C 111, in two separate viewing periods (VPs), at a 3sigma level in each. A new source, GROJ0426+3747, appea rs to be present nearby, seen only in the >1000MeV data. For >100MeV, the data are in agreement with only one source (at the original cata log position) accounting for most of the EGRET-detected emission of 3 EGJ0416+3650. A follow-up Swift UVOT/XRT observation reveals one mode rately bright X-ray source in the error box of 3EGJ0416+3650, but bec ause of the large EGRET position uncertainty, it is not certain that the X-ray and Gamma-ray sources are associated. A Swift observation of GROJ0426+3747 detected no X.ray source nearby.

Hartman, Robert C.; Kadler, Matthias; Tueller, Jack

2008-01-01

117

Gamma-Ray Emission from the Broad-Line Radio Galaxy 3C 111  

NASA Technical Reports Server (NTRS)

The broad-line radio galaxy 3C 111 has been suggested as the counterpart of the y-ray source 3EG J0416+3650. While 3C 111 meets most of the criteria for a high-probability identification, like a bright flat-spectrum radio core and a blazar-like broadband SED, in the Third EGRET Catalog, the large positional offset of about 1.5' put 3C 111 outside the 99% probability region for 3EG J0416+3650, making this association questionable. We present a re-analysis of all available archival data for 3C 111 from the EGRET archives, resulting in detection of variable hard-spectrum high-energy gamma-ray emission above 1000 MeV from a position close to the nominal position of 3C 111, in three separate viewing periods (VPs), at a 3sigma level in each. A second variable hard-spectrum source is present nearby. At >100 MeV, one variable soft-spectrum source seems to account for most of the EGRET-detected emission of 3EG J0416+3650. A follow-up Swift UVOT/XRT observation reveals one moderately bright X-ray source in the error box of 3EG J0416+3650, but because of the large EGRET position uncertainty, it is not certain that the X-ray and gamma-ray sources are associated. Another Swift observation near the second (unidentified) hard gamma-ray source detected no X-ray source nearby.

Hartman, Robert C.; Kadler, M.; Tueller, Jack

2008-01-01

118

Morphologies And SEDs Of Low-redshift Low-ionization Broad Absorption Line QSOs  

NASA Astrophysics Data System (ADS)

We present optical and infrared HST/WFC3 images and Spitzer IRS spectra and MIPS photometry of a large volume-limited sample of 22 SDSS-selected Low-ionization Broad Absorption Line QSOs (LoBALs) at 0.5 < z < 0.6. Previous studies of LoBALs show that their host galaxies tend to be ultraluminous infrared galaxies (ULIRGs) that are undergoing mergers and that have young stellar populations. We test the hypothesis that LoBALs are a transition phase from dust-embedded, ultra-luminous infrared QSOs toward unobscured type-1 QSOs by studying their morphologies for signs of recent tidal interaction and estimating star formation activity from their far-infrared SEDs. Our results show that, while the majority of the LoBALs are similar to type-1 QSOs in terms of their mid- and far-infrared properties, at least 20%, and as many as 60%, of the LoBALs are characterized by higher infrared luminosities typical of ULIRGs and star formation rates 150-300 solar masses per year. Most of the LoBALs show apparent signs of tidal disturbance. We model the 2D host galaxy profiles with GALFIT and subtract simple bulge and disk models to reveal any fine structure, relic of past merger event. We correlate the morphologies and the merger stages with infrared luminosities, star formation rates, and mid-infrared spectral properties of this sample from Spitzer data. The unusually high fraction of LoBALs with high infrared luminosities and host galaxies showing signs of tidal interaction, in principle, fits the evolutionary paradigm, implying that LoBALs are rapidly transitioning from a ULIRG phase to a more quiescent phase with star formation activity typical of type-1 QSOs.

Lazarova, Mariana S.; Canalizo, G.; Lacy, M.; Sajina, A.

2012-01-01

119

XMM-Newton Spectroscopy of the X-ray Detected Broad Absorption Line QSO CSO 755  

NASA Technical Reports Server (NTRS)

We present the results from XMM-Newton observations of the highly optically polarized broad absorption line quasar (BALQSO) CSO 755. By analyzing its X-ray spectrum with a total of approximately 3000 photons we find that this source has an X-ray continuum of "typical" radio-quiet quasars, with a photon index of Gamma=1.83, and a rather flat (X-ray bright) intrinsic optical-to-X-ray spectral slope of alpha_ox=- 1.51. The source shows evidence for intrinsic absorption, and fitting the spectrum with a neutral-absorption model gives a column density of N_H approximately 1.2x10^22 cm^{-2}; this is among the lowest X-ray columns measured for BALQSOs. We do not detect, with high significance, any other absorption features in the X-ray spectrum. Upper limits we place on the rest-frame equivalent width of a neutral (ionized) Fe K-alpha line, less than =180 eV (less than =120 eV), and on the Compton-reflection component parameter, R less than =0.2, suggest that most of the X-rays from the source are directly observed rather than being scattered or reflected; this is also supported by the relatively flat intrinsic alpha ox we measure. The possibility that most of the X-ray flux is scattered due to the high level of UV-optical polarization is ruled out. Considering data for 46 BALQSOs from the literature, including CSO 755, we have found that the UV-optical continuum polarization level of BALQSOs is not correlated with any of their X-ray properties. A lack of significant short-term and long-term X-ray flux variations in the source may be attributed to a large black-hole mass in CSO 755. We note that another luminous BALQSO, PG 2112+059, has both similar shallow C IV BALs and moderate X-ray absorption.

Brandt, Niel

2005-01-01

120

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

121

Correlation between the line width and the line flux of the double-peaked broad H? of 3C390.3  

NASA Astrophysics Data System (ADS)

In this paper, we carefully check the correlation between the line width (second moment) and the line flux of the double-peaked broad H? of the well-known mapped active galactic nucleus (AGN) 3C390.3 in order to show some further distinctions between double-peaked emitters and normal broad-line AGN. Based on the virialization assumption MBH ? RBLR × V2(BLR) and the empirical relation RBLR ? L˜0.5, one strong negative correlation between the line width and the line flux of the double-peaked broad lines should be expected for 3C390.3, such as the negative correlation confirmed for the mapped broad-line object NGC 5548, RBLR × V2(BLR) ? L˜0.5 × ?2 = constant. Moreover, based on the public spectra around 1995 from the AGN WATCH project for 3C390.3, one reliable positive correlation is found between the line width and the line flux of the double-peaked broad H?. In the context of the proposed theoretical accretion disc model for double-peaked emitters, the unexpected positive correlation can be naturally explained, due to different time delays for the inner and outer parts of the disc-like broad-line region (BLR) of 3C390.3. Moreover, the virialization assumption is checked and found to be still available for 3C390.3. However, the time-varying size of the BLR of 3C390.3 cannot be expected by the empirical relation RBLR ? L˜0.5. In other words, the mean size of the BLR of 3C390.3 can be estimated by the continuum luminosity (line luminosity), while the continuum emission strengthening leads to the size of BLR decreasing (not increasing) in different moments for 3C390.3. Then, we compared our results of 3C390.3 with the previous results reported in the literature for the other double-peaked emitters, and found that before to clearly correct the effects from disc physical parameters varying (such as the effects of disc precession) for long-term observed line spectra, it is not so meaningful to discuss the correlation of the line parameters of double-peaked broad lines. Furthermore, due to the probable `external' ionizing source with so far unclear structures, it is hard to give one conclusion that the positive correlation between the line width and the line flux can be found for all double-peaked emitters, even after the considerations of disc physical parameters varying. However, once one positive correlation of broad-line parameters is found, the accretion disc origination of the broad line should be considered first.

Zhang, Xue-Guang

2013-03-01

122

EVIDENCE FOR AN INTERMEDIATE LINE REGION IN ACTIVE GALACTIC NUCLEI's INNER TORUS REGION AND ITS EVOLUTION FROM NARROW TO BROAD LINE SEYFERT I GALAXIES  

SciTech Connect

A two-component model for the broad-line region (BLR) of active galactic nuclei (AGNs) has been suggested for many years but not widely accepted. This model indicates that the broad line can be described with the superposition of two Gaussian components (very broad Gaussian component and intermediate Gaussian component (IMGC)) which are from two physically distinct regions, i.e., very broad line region (VBLR) and intermediate line region. We select a Sloan Digital Sky Survey sample to further confirm this model and give a detailed analysis of the geometry, density, and evolution of these two regions. The microlensing result of the BLR in J1131-1231 and some unexplained phenomena in reverberation mapping (RM) experiment provide supportive evidence for this model. Our results indicate that the radius obtained from the emission line RM normally corresponds to the radius of the VBLR, and the existence of the IMGC may affect the measurement of the black hole masses in AGNs. The deviation of NLS1s from the M-sigma relation and the type II AGN fraction as a function of luminosity can be explained in this model in a coherent way. The evolution of the two emission regions may be related to the evolutionary stages of the BLRs of AGNs from NLS1s to BLS1s. Based on the results presented here, a unified picture of the hierarchical evolution of a black hole, a dust torus, and a galaxy is proposed.

Zhu Ling; Zhang Shuangnan [Department of Physics and Tsinghua Center for Astrophysics, Tsinghua University, Beijing 100084 (China); Tang Sumin [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)], E-mail: zhul04@mails.tsinghua.edu.cn, E-mail: zhangsn@tsinghua.edu.cn, E-mail: zhangsn@tsinghua.edu.cn

2009-08-01

123

Broad-band simultaneous measurement of complex permittivity and permeability using a coaxial discontinuity  

Microsoft Academic Search

A technique for simultaneously measuring the real and imaginary parts of both the permittivity and the permeability of a given material is discussed. A gap in a coaxial line is filled with the material under test. Complex permittivity and permeability are computed from the S-parameter (S11 and S21) measurement made on the gap, taking into account higher-order modes excited at

NOUR-EDDINE BELHADJ-TAHAR; ARLETTE FOURRIER-LAMER; HELIE DE CHANTERAC

1990-01-01

124

A COMPARISON OF BROAD IRON EMISSION LINES IN ARCHIVAL DATA OF NEUTRON STAR LOW-MASS X-RAY BINARIES  

SciTech Connect

Relativistic X-ray disklines have been found in multiple neutron star low-mass X-ray binaries, in close analogy with black holes across the mass scale. These lines have tremendous diagnostic power and have been used to constrain stellar radii and magnetic fields, often finding values that are consistent with independent timing techniques. Here, we compare CCD-based data from Suzaku with Fe K line profiles from archival data taken with gas-based spectrometers. In general, we find good consistency between the gas-based line profiles from EXOSAT, BeppoSAX, and RXTE and the CCD data from Suzaku, demonstrating that the broad profiles seen are intrinsic to the line and not broad due to instrumental issues. However, we do find that when fitting with a Gaussian line profile, the width of the Gaussian can depend on the continuum model in instruments with low spectral resolution, though when the different models fit equally well the line widths generally agree. We also demonstrate that three BeppoSAX observations show evidence for asymmetric lines, with a relativistic diskline model providing a significantly better fit than a Gaussian. We test this by using the posterior predictive p-value method, and bootstrapping of the spectra to show that such deviations from a Gaussian are unlikely to be observed by chance.

Cackett, Edward M. [Department of Physics and Astronomy, Wayne State University, 666 W. Hancock St, Detroit, MI 48201 (United States); Miller, Jon M. [Department of Astronomy, University of Michigan, 500 Church St, Ann Arbor, MI 48109-1042 (United States); Reis, Rubens C.; Fabian, Andrew C. [Institute of Astronomy, University of Cambridge, Madingley Rd, Cambridge, CB3 0HA (United Kingdom); Barret, Didier, E-mail: ecackett@wayne.edu [Institut de Recherche en Astrophysique et Planetologie, 9, Avenue du Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4 (France)

2012-08-10

125

EVIDENCE FOR THE INTERMEDIATE BROAD-LINE REGION OF REVERBERATION-MAPPED ACTIVE GALACTIC NUCLEUS PG 0052+251  

SciTech Connect

We study the properties of the broad-line region (BLR) of a well-known reverberation-mapped active galactic nucleus (AGN) in order to find reliable evidence for the intermediate BLR. We first check properties of the mapped AGN collected from the literature in the plane of {sigma}{sup 2}{sub H}{beta}/{sigma}H{alpha} {sup 2} versus R {sup H}{alpha}{sub BLR}/R{sub BLR} {sup H}{beta}. Commonly, virial black hole masses based on observed broad H{alpha} and H{beta} should be coincidental. However, among the mapped objects, PG 0052 and NGC 4253 are two apparent outliers in the plane of {sigma}{sup 2}{sub H}{beta}/{sigma}H{alpha} {sup 2} versus R {sup H}{alpha}{sub BLR}/R{sub BLR} {sup H}{beta}, which indicates that BLRs of PG 0052 and NGC 4253 have some special characters. Based on the 55 public spectra of PG 0052, the BLR of PG 0052 has been carefully studied in detail. We find that the line width ratio of the total observed broad H{alpha} to the total observed broad H{beta} is {approx}0.7, which is much smaller than the theoretical/observational value of {approx}0.9. Furthermore, the flux ratio of the total broad H{alpha} to the total broad H{beta} is about 6.8 (Balmer decrement), which is not a reasonable value for the blue quasar PG 0052+251. Moreover, properties of line cores based on the principal component analysis technique confirm that there is one inner broad component and one seriously obscured intermediate broad component in the BLR of PG 0052. If the seriously obscured intermediate BLR was accepted, properties of PG 0052 in the plane of {sigma}{sup 2}{sub H}{beta}/{sigma}H{alpha} {sup 2} versus R {sup H}{alpha}{sub BLR}/R{sub BLR} {sup H}{beta} could be reproduced, which indicates that the intermediate BLR actually is appropriate for the mapped quasar PG 0052+251. Finally, the large distance between the inner and the intermediate components of the BLR based on the results of the cross-correlation function rejects the possibility that the intermediate component is probably an extended part of the inner component of the BLR.

Zhang Xueguang, E-mail: xgzhang@pmo.ac.cn [Purple Mountain Observatory, Chinese Academy of Sciences, 2 Beijing Xi Lu, Nanjing, Jiangsu 210008 (China)

2011-11-10

126

Broad line emission from iron K- and L-shell transitions in the active galaxy 1H 0707-495.  

PubMed

Since the 1995 discovery of the broad iron K-line emission from the Seyfert galaxy MCG-6-30-15 (ref. 1), broad iron K lines have been found in emission from several other Seyfert galaxies, from accreting stellar-mass black holes and even from accreting neutron stars. The iron K line is prominent in the reflection spectrum created by the hard-X-ray continuum irradiating dense accreting matter. Relativistic distortion of the line makes it sensitive to the strong gravity and spin of the black hole. The accompanying iron L-line emission should be detectable when the iron abundance is high. Here we report the presence of both iron K and iron L emission in the spectrum of the narrow-line Seyfert 1 galaxy 1H 0707-495. The bright iron L emission has enabled us to detect a reverberation lag of about 30 s between the direct X-ray continuum and its reflection from matter falling into the black hole. The observed reverberation timescale is comparable to the light-crossing time of the innermost radii around a supermassive black hole. The combination of spectral and timing data on 1H 0707-495 provides strong evidence that we are witnessing emission from matter within a gravitational radius, or a fraction of a light minute, from the event horizon of a rapidly spinning, massive black hole. PMID:19478778

Fabian, A C; Zoghbi, A; Ross, R R; Uttley, P; Gallo, L C; Brandt, W N; Blustin, A J; Boller, T; Caballero-Garcia, M D; Larsson, J; Miller, J M; Miniutti, G; Ponti, G; Reis, R C; Reynolds, C S; Tanaka, Y; Young, A J

2009-05-28

127

WISE J233237.05-505643.5: A Double-peaked, Broad-lined Active Galactic Nucleus with a Spiral-shaped Radio Morphology  

NASA Astrophysics Data System (ADS)

We present radio continuum mapping, optical imaging, and spectroscopy of the newly discovered double-peaked, broad-lined active galactic nucleus (AGN) WISE J233237.05-505643.5 at redshift z = 0.3447. This source exhibits an FR-I and FR-II hybrid morphology, characterized by a bright core, jet, and Doppler-boosted lobe structures in Australian Telescope Compact Array continuum maps at 1.5, 5.6, and 9 GHz. Unlike most FR-II objects, W2332-5056 is hosted by a disk-like galaxy. The core has a projected 5'' linear radio feature that is perpendicular to the curved primary jet, hinting at unusual and complex activity within the inner 25 kpc. The multi-epoch, optical-near-IR photometric measurements indicate significant variability over a 3-20 yr baseline from the AGN component. Gemini South optical data show unusual double-peaked emission-line features: the centroids of the broad-lined components of H? and H? are blueshifted with respect to the narrow lines and host galaxy by ~3800 km s-1. We examine possible cases that involve single or double supermassive black holes in the system and discuss the required future investigations to disentangle the mysterious nature of this system.

Tsai, Chao-Wei; Jarrett, T. H.; Stern, Daniel; Emonts, Bjorn; Barrows, R. Scott; Assef, Roberto J.; Norris, Ray P.; Eisenhardt, Peter R. M.; Lonsdale, Carol; Blain, Andrew W.; Benford, Dominic J.; Wu, Jingwen; Stalder, Brian; Stubbs, Christopher W.; High, F. William; Li, K. L.; Kong, Albert K. H.

2013-12-01

128

Chandra High Resolution Spectroscopy of the Circumnuclear Matter in the Broad Line Radio Galaxy, 3C 445  

NASA Technical Reports Server (NTRS)

We present evidence for X-ray line emitting and absorbing gas in the nucleus of the Broad-Line Radio Galaxy (BLRG), 3C445. A 200 ks Chandra LETG 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 greater than 10(sup 10) cm(sup -3), while the lines are velocity broadened with a mean width of 2600 km s(sup -1). The density and widths of the ionized lines indicate an origin of the gas on sub-parsec scales in the Broad Line Region (BLR). The X-ray continuum of 3C 445 is heavily obscured 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 approximately 10000 km s(sup -1).

Reeves, J. N.; Gofford, J.; Braito, V.; Sambruna, R.

2010-01-01

129

Broad iron emission line and kilohertz quasi-periodic oscillations in the neutron star system 4U 1636-53  

NASA Astrophysics Data System (ADS)

Both the broad iron (Fe) line and the frequency of the kilohertz quasi-periodic oscillations (kHz QPOs) in neutron star low-mass X-ray binaries (LMXBs) can potentially provide independent measures of the inner radius of the accretion disc. We use XMM-Newton and simultaneous Rossi X-ray Timing Explorer observations of the LMXB 4U 1636-53 to test this hypothesis. We study the properties of the Fe K? emission line as a function of the spectral state of the source and the frequency of the kHz QPOs. We find that the inner radius of the accretion disc deduced from the frequency of the upper kHz QPO varies as a function of the position of the source in the colour-colour diagram, in accordance with previous work and with the standard scenario of accretion disc geometry. On the contrary, the inner disc radius deduced from the profile of the iron line is not correlated with the spectral state of the source. The values of the inner radius inferred from kHz QPOs and iron lines, in four observations, do not lead to a consistent value of the neutron star mass, regardless of the model used to fit the iron line. Our results suggest that either the kHz QPO or the standard relativistic Fe line interpretation does not apply for this system. Furthermore, the simultaneous detection of kHz QPOs and broad iron lines is difficult to reconcile with models in which the broadening of the iron line is due to the reprocessing of photons in an outflowing wind.

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

2014-06-01

130

Microlensing of the broad-line region in the quadruply imaged quasar HE0435-1223  

NASA Astrophysics Data System (ADS)

Using infrared spectra of the z = 1.693 quadruply lensed quasar HE0435-1223 acquired in 2009 with the spectrograph SINFONI at the ESO Very Large Telescope, we have detected a clear microlensing effect in images A and D. While microlensing affects the blue and red wings of the H? line profile in image D very differently, it de-magnifies the line core in image A. The combination of these different effects sets constraints on the line-emitting region; these constraints suggest that a rotating ring is at the origin of the H? line. Visible spectra obtained in 2004 and 2012 indicate that the MgII line profile is microlensed in the same way as the H? line. Our results therefore favour flattened geometries for the low-ionization line-emitting region, for example, a Keplerian disk. Biconical models cannot be ruled out but require more fine-tuning. Flux ratios between the different images are also derived and confirm flux anomalies with respect to estimates from lens models with smooth mass distributions. Based on observations made with the ESO-VLT, Paranal, Chile; Proposal 084.B-0013 (PI: Rix).Tables 2, 3 and Appendix A are available in electronic form at http://www.aanda.org

Braibant, L.; Hutsemékers, D.; Sluse, D.; Anguita, T.; García-Vergara, C. J.

2014-05-01

131

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

132

A REVERBERATION LAG FOR THE HIGH-IONIZATION COMPONENT OF THE BROAD-LINE REGION IN THE NARROW-LINE SEYFERT 1 Mrk 335  

SciTech Connect

We present the first results from a detailed analysis of photometric and spectrophotometric data on the narrow-line Seyfert 1 (NLS1) galaxy Mrk 335, collected over a 120 day span in the fall of 2010. From these data we measure the lag in the He II {lambda}4686 broad emission line relative to the optical continuum to be 2.7 {+-} 0.6 days and the lag in the H{beta}{lambda}4861 broad emission line to be 13.9 {+-} 0.9 days. Combined with the line width, the He II lag yields a black hole mass M{sub BH} = (2.6 {+-} 0.8) Multiplication-Sign 10{sup 7} M{sub Sun }. This measurement is consistent with measurements made using the H{beta}{lambda}4861 line, suggesting that the He II emission originates in the same structure as H{beta}, but at a much smaller radius. This constitutes the first robust lag measurement for a high-ionization line in an NLS1 galaxy and supports a scenario in which the He II emission originates from gas in virial motion rather than outflow.

Grier, C. J.; Peterson, B. M.; Pogge, R. W.; Martini, Paul; Zu, Y.; Kochanek, C. S.; Shappee, B. J.; Stanek, K. Z.; Araya Salvo, C.; Beatty, T. G.; Bird, J. C. [Department of Astronomy, The Ohio State University, 140 W 18th Avenue, Columbus, OH 43210 (United States); Denney, K. D. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, One Park Place South SE, Suite 700, Atlanta, GA 30303 (United States); Sergeev, S. G.; Borman, G. A. [Crimean Astrophysical Observatory, P/O Nauchny Crimea 98409 (Ukraine); Kaspi, S. [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Bord, D. J. [Department of Natural Sciences, The University of Michigan-Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128 (United States); Che, X. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 41809 (United States); Chen, C.; Cohen, S. A. [Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States); and others

2012-01-15

133

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

134

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

135

Comparison of the performance of three diagnostic algorithms for regular broad complex tachycardia in practical application.  

PubMed

The authors previously proposed a Bayesian approach to the electrocardiographic diagnosis of regular broad complex tachycardia (BCT), which can be due to VT or supraventricular tachycardia with aberrant conduction (SVTAC). They also published an account comparing the theoretical merits in the design of two of the most commonly used diagnostic algorithms for the same purpose, those of Brugada et al. and Griffith et al. In this study, a direct head-to-head comparison was performed on the practical performances of the three algorithms in this study. A set of 111 ECGs showing regular BCT (77 VT, 34 SVTAC) whose diagnoses were confirmed by electrophysiological study was shown to five internists in general medicine at a district general hospital. The observers were asked to comment on whether the ECG criteria in the three algorithms tested were fulfilled or not, and a computer program then derived the corresponding diagnoses. The sensitivity and specificity for VT achieved by the Brugada algorithm were 92% and 44%, 92% and 44% by the Griffith algorithm, and 97% and 56% by the Bayesian algorithm. The Bayesian algorithm achieved a higher sensitivity and specificity than the other two algorithms, but the differences are not statistically significant (P = 0.6583 and P = 0.5334, respectively). The Brugada, Griffith, and Bayesian algorithms show comparable performances in terms of overall sensitivity and specificity when tested in practice. Of the three algorithms, the Griffith algorithm excels in simplicity and is the easiest to implement in practice. The Bayesian algorithm achieved slightly higher values for sensitivity and specificity than the Brugada and Griffith algorithms but may be more suitable for automated computer-aided diagnosis of ECG due to its complexity. PMID:12049375

Lau, Ernest W; Ng, G André

2002-05-01

136

Broadly applicable Z- and diastereoselective ring-opening/cross-metathesis catalyzed by a dithiolate ru complex.  

PubMed

A broadly applicable Ru-catalyzed protocol for Z-selective ring-opening/cross-metathesis (ROCM) is disclosed. In addition to reactions relating to terminal alkenes of different sizes, the first examples of Z-selective ROCM processes involving heteroaryl olefins, 1,3-dienes, and O- and S-substituted alkenes as well as allylic and homoallylic alcohols are reported. Z-Selective transformations with an ?-substituted allylic alcohol are shown to afford congested Z alkenes with high diastereoselectivity. Transformations are performed in the presence of 2.0-5.0?mol?% of a recently disclosed Ru-based dithiolate complex that can be easily prepared in a single step from commercially available starting materials. Typically, transformations proceed at ambient temperature and are complete within eight hours; products are obtained in up to 97?% yield, >98:2 Z/E, and >98:2 diastereomeric ratio. The present investigations reveal a mechanistically significant attribute of the Ru-based dithiolates that arises from electrostatic interactions with anionic S-based ligands. PMID:24474558

Koh, Ming Joo; Khan, R Kashif M; Torker, Sebastian; Hoveyda, Amir H

2014-02-10

137

Broad frequency-band characterizations of electromagnetic energy propagation in planar thin-film transmission lines  

NASA Astrophysics Data System (ADS)

Thin-film transmission lines are experimentally characterized in the frequency range from 10 MHz to 110 GHz. Scattering (S-) parameters for several test lines are measured. Then, two important transmission line parameters ( i.e., the propagation constant and characteristic impedance) are determined in the measured frequency range. The resonances, which are inevitable in a practical experimental environment, are carefully eliminated by de-embedding parasitic effects and by determining the frequency-variant dielectric permittivity based on the Debye model. Based on the experimental work, we showed that the conventional skin-effect model may not be accurate for high-frequencies. Further, the 3-dimensional (3D) numerical field solver does not reflect the radiation loss at high-frequency. Finally, in the millimeter (mm)-wave region, all the three loss mechanisms due to the skin-effect, dielectric polarization, and electromagnetic radiation have to be taken into account.

Kim, Dongchul; Eo, Yungseon

2014-04-01

138

Broad iron K emission line and spectral variability of the Seyfert 2 galaxy IRAS 18325-5926  

NASA Technical Reports Server (NTRS)

A very broad iron K alpha emission line is observed in the Advanced Satellite for Cosmology and Astrophysics (ASCA) spectrum of the Seyfert 2 galaxy IRAS 18325-5926. The line profile is peaked at 6.9 keV and skewed down to 4 keV. The breadth and shift of the line energy can be interpreted by Doppler and relativistic effects in a cold accretion disk about a black hole with a intermediate inclination of between 40 and 50 deg. The steep spectral slope and the fast variability on a timescale of 10(exp 4) s are confirmed for this object. A study of spectral variability reveal that the X-ray flux change mainly occurred above 1 keV and the soft X-ray component below 1 keV appears to be less variable or constant and should lie outside of the nuclear obscuration.

Iwasawa, K.; Fabian, A. C.; Mushotsky, R. F.; Brandt, W. N.; Awaki, H.; Kunieda, H.

1996-01-01

139

Study of the broad Fe K-alpha emission line in the bright source GX 17+2  

NASA Astrophysics Data System (ADS)

We propose to observe the Z source GX 17+2 with XMM-Newton for 40 ks, to perform a detailed study of the iron K-shell feature to assess its origin. A broad emission feature compatible with a highly ionized iron line has been detected both in BeppoSAX and in Chandra observations of the source. The Chandra spectrum suggests that the line might be of relativistic origin, but the large collecting area of XMM-Newton is needed to resolve unambiguously the line profile, which can give important information on the dynamics of accretion and on the structure of neutron stars. Use of the modified timing mode will allow to maximize the time efficiency of the observation and to perform high-statistics timing analysis.

Lavagetto, Giuseppe

2007-10-01

140

Broadly tunable parametric line emission from ?-barium borate on pumping with picosecond pulses  

Microsoft Academic Search

Tunable line emission (LE) over a large wavelength region (340–980nm) is obtained by pumping thick crystals of ?-barium borate (BBO) with picosecond pulses at 532nm. Phenomena of group velocity dispersion, diffraction and phase matching take place simultaneously such that the radiation shows specific features that are characteristic of (i) strongly coupled fundamental and harmonic fields, (ii) amplified phase matched superfluorescence,

Ambika Nautiyal; Prem B. Bisht

2008-01-01

141

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

142

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

143

Microfibrillar meshwork of the synovial lining and associated broad banded collagen: a clue to identity  

Microsoft Academic Search

The surface layer of synovial interstitium lining the rabbit knee was studied by transmission electron microscopy. Over a distance of 2-3 microns normal to the surface the interstitium contained a network of fine microfibrils (diameter 9.3 (0.7) nm, mean (SEM] which was quite dense in places (fractional area of projection 0.189 (0.023], and stained with ruthenium red. Periodic collagen fibrils

J R Levick; J N McDonald

1990-01-01

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

The BROAD-LINE TYPE Ic SUPERNOVA SN 2007ru: ADDING TO THE DIVERSITY OF TYPE Ic SUPERNOVAE  

SciTech Connect

Photometric and spectral evolution of the Type Ic supernova SN 2007ru until around 210 days after maximum are presented. The spectra show broad spectral features due to very high expansion velocity, normally seen in hypernovae. The photospheric velocity is higher than other normal Type Ic supernovae (SNe Ic). It is lower than SN 1998bw at {approx}8 days after the explosion, but is comparable at later epochs. The light curve (LC) evolution of SN 2007ru indicates a fast rise time of 8 {+-} 3 days to B-band maximum and postmaximum decline more rapid than other broad-line SNe Ic. With an absolute V magnitude of -19.06, SN 2007ru is comparable in brightness with SN 1998bw and lies at the brighter end of the observed SNe Ic. The ejected mass of {sup 56}Ni is estimated to be {approx}0.4 M {sub sun}. The fast rise and decline of the LC and the high expansion velocity suggest that SN 2007ru is an explosion with a high kinetic energy/ejecta mass ratio (E {sub K}/M {sub ej}). This adds to the diversity of SNe Ic. Although the early phase spectra are most similar to those of broad-line SN 2003jd, the [O I] line profile in the nebular spectrum of SN 2007ru shows the singly peaked profile, in contrast to the doubly peaked profile in SN 2003jd. The singly peaked profile, together with the high luminosity and the high expansion velocity, may suggest that SN 2007ru could be an aspherical explosion viewed from the polar direction. Estimated oxygen abundance 12 + log(O/H) of {approx}8.8 indicates that SN 2007ru occurred in a region with nearly solar metallicity.

Sahu, D. K.; Anupama, G. C.; Gurugubelli, Uday K. [Indian Institute of Astrophysics, II Block Koramangala, Bangalore 560034 (India); Tanaka, Masaomi; Nomoto, Ken'ichi [Department of Astronomy, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan)], E-mail: dks@iiap.res.in, E-mail: gca@iiap.res.in, E-mail: uday@iiap.res.in, E-mail: mtanaka@astron.s.u-tokyo.ac.jp, E-mail: nomoto@astron.s.u-tokyo.ac.jp

2009-05-20

146

Broad Spectrum of Skeletal Malformation Complex in Patients with Cleidocranial Dysplasia Syndrome: Radiographic and Tomographic Study  

PubMed Central

Purpose Cleidocranial dysplasia is an autosomal dominant disorder characterized by defective ossification of the intramembraneous ossification (primarily the clavicles, cranium, and pelvis), and it is caused by mutations in the RUNX2 gene that is responsible for osteoblast differentiation. Spine deformities were of progressive nature and considered to be the major orthopedic abnormalities encountered in our practice in patients with cleidocranial dysplasia. We aimed to further delineate the underlying spine pathology and its etiological understanding. Extraspinal deformities were dealt with respectively. Material and methods In this paper, we describe 7 patients who were consistent with the phenotypic and the genotypic characterization of cleidocranial dysplasia. Reformatted computed tomography (CT) scans have been applied in several instances to further understand the underlying pathology of progressive spine tilting. Radiographs were sufficient to illustrate other skeletal malformations. Results Anatomical survey demonstrates that a broad spectrum of frequently unrecognized orthopedic aberrations were encountered. We believe that torticollis has evolved in connection with the persistence of synchondrosis of the skull base and the upper cervical spine and these are strongly correlated to the well-known pathology of posterior occipital synchondrosis. Similarly, scoliosis and kyphoscoliosis resulted from the pathologic aberration of the cartilaginous stage of disrupted embryological development. All our results are discussed for the first time. Coxa vara, patellar dysplasia, and genu valgum were observed as extraspinal deformities. Conclusion This paper includes for the first time the anatomical analysis of the malformation complex of the craniocervical and the entire spine in patients with cleidocranial dysplasia. Reformatted CT scan was the modality of choice. We were able to illustrate that the persistence of skull base and the cervical spine synchondrosis were correlated with the pathological mechanism of the posterior occipital synchondrosis. Therefore, injuries to the craniocervical region in these patients might lead to a wide range of dreadful complications, ranging from complete atlanto-occipital or atlanto-axial dislocation to nondisplaced occipital condyle avulsion fractures with the possibility of morbid and or mortal outcome. On the other hand, the persistence of a cartilaginous spine was the reason behind the progressive spine tilting. This pathological form can be considered as a notoriously unpredictable malformation complex. The value of presenting these patients is to demonsterate that the genotype is not a precise index to assess the severity and the natural history of the phenotype.

Al Kaissi, Ali; Ben Chehida, Farid; Kenis, Vladimir; Ganger, Rudolf; Radler, Christof; Hofstaetter, Jochen G.; Klaushofer, Klaus; Grill, Franz

2013-01-01

147

Echo mapping of active galactic nuclei broad-line regions: Fundamental algorithms  

NASA Technical Reports Server (NTRS)

We formulate and test a series of algorithms for echo mapping the emission-line regions near active galactic nuclei from measurements of correlated variability in their line and continuum light curves. The linear regularization method (LRM) employs a direct inversion of evenly spaced light-curve data, with a regularization parameter that can be used to control the trade-off between noise and resolution. Matrix formulas express the formal solution as well as its variance and covariance in terms of uncertainties in the measurements. Unlike the maximum-entropy method (MEM), LRM applies to kernels with both positive and negative values, but the results are somewhat limited by ringing effects. A positivity constraint proves effective in controlling the ringing. MEM combines regularization and positivity in a natural way, but similar results are also found using positivity constraints with nonentropic regularization functions. Direct inversions of unevenly sampled light curves require interpolating the noisy data. In this case better results are found by solving for both the continuum light curve and kernel function in a simultaneous fit to the data. Our conclusion is that while echo mapping currently gives ambiguous results, the algorithms are not the limiting factor. Progress depends on efforts to increase the accuracy and completeness of sampling of the observed light curves.

Vio, Roberto; Horne, Keith; Wamsteker, Willem

1994-01-01

148

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

149

GRIS detection of Al-26 1809 keV line emission from the Galactic center region as a broad line  

NASA Technical Reports Server (NTRS)

The gamma ray imaging spectrometer (GRIS) was used to observe the 1809 keV emission from the Galactic center region. The observed line is broader than the instrument resolution. The measured intrinsic width is 5.4 +/- 1.4 keV full width half medium, which is more than three times the maximum Doppler broadening expected due to Galactic rotation. The detection of such a wide feature, suggesting a high dispersion velocity has implications for the origin of Galactic Al-26. It suggests a supernova explosion origin or a Wolf-Rayet stellar wind origin of Al-26. The fact that the Al-26 has not come to rest after 10(exp 6) years presents a challenge to the current understanding of the Al-26 production and propagation in the Galaxy.

Naya, Juan E.; Barthelmy, Scott D.; Bartlett, Lyle M.; Gehrels, Neil; Leventhal, Marvin; Parsons, Ann; Teegarden, Bonnard J.; Tueller, Jack

1997-01-01

150

Black Hole Mass and Accretion Rate of Active Galactic Nuclei with Double-peaked Broad Emission Lines  

NASA Astrophysics Data System (ADS)

Using an empirical relation between the broad-line region size and optical continuum luminosity, we estimated the black hole mass and accretion rate for 135 active galactic nuclei (AGNs) with double-peaked broad emission lines in two samples, one from the Sloan Digital Sky Survey (SDSS) and the other from a survey of radio-loud broad emission line AGNs. With black hole masses ranging from 3×107Msolar to 5×109Msolar, these AGNs have dimensionless accretion rates (Eddington ratios) between 0.001 and 0.1 and bolometric luminosity between 1043 and 1046 ergs s-1, both values being significantly larger than those of several previously known low-luminosity (Lbol<1043 ergs s-1) double-peaked AGNs. The optical-X-ray spectra indices, ?OX, of these high-luminosity double-peaked AGNs are between 1 and 1.9, systematically larger than those of low-luminosity objects, which are around 1. Modest correlations (with a Spearman rank correlation coefficient of 0.60) of the ?OX value with the Eddington ratio and bolometric luminosity have been found, indicating that double-peaked AGNs with higher Eddington ratios or higher luminosity tend to have larger ?OX values. Based on these results, we suggested that the accretion process in the central region of some high-luminosity double-peaked emission line AGNs (especially those with Eddington ratios larger than 0.01) is probably different from that of low-luminosity objects, in which a well-known ADAF-like accretion flow was thought to exist. It is likely that the accretion physics in some high-luminosity double-peaked AGNs is similar to that in normal type 1 AGNs, which is also supported by the presence of possible big blue bumps in the spectra of some double-peaked AGNs with higher Eddington ratios. We note that the prototype double-peaked emission line AGN, Arp 102B, which has a black hole mass of 108 Msolar and a dimensionless accretion rate of 0.001, may be an ``intermediate'' object between the high- and low-luminosity double-peaked AGNs. In addition, we found an apparent strong anticorrelation (with a Spearman rank correlation coefficient of -0.79) between the peak separation of double-peaked profiles and Eddington ratios. However, such an anticorrelation is probably induced by a strong correlation between the peak separation and emission-line widths and needs to be confirmed by future work. If it is real, it may provide us another clue to understanding why double-peaked broad emission lines were hardly found in luminous AGNs with Eddington ratios larger than 0.1.

Wu, Xue-Bing; Liu, F. K.

2004-10-01

151

Ultrastructure of spermatogenesis in the white-lined broad-nosed bat, Platyrrhinus lineatus (Chiroptera: Phyllostomidae).  

PubMed

Spermatogenesis, the remarkable process of morphological and biochemical transformation and cell division of diploid stem cells into haploid elongated spermatozoa, is one of the most complex cell differentiations found in animals. This differentiation process has attracted extensive studies, not only because the process involves many radical changes in the cell shape and biochemistry, but also because the phases and steps of differentiation have provided a better basis for analyzing the seminiferous epithelium cycle. Thus, this study aimed to characterize ultrastructurally the spermatogenesis process in the bat Platyrrhinus lineatus in order to provide a basis for determining the stages of spermatogenesis and to facilitate comparisons of the process between bat species and other vertebrates. Based on ultrastructural characteristics three main types of spermatogonia could be accurately identified: A(d), A(p) and B; the differentiation of spermatids was clearly divided into 12 steps (steps 1-3: Golgi phase, steps 4-5: cap phase, steps 6-9: acrosomal phase and steps 10-12: maturation phase). The ultrastructure of spermatozoa, Leydig cells and Sertoli cells was characterized; and some processes including nucleolar disorganization and the formation of synaptonemal complexes, acrosome and chromatoid body were discussed. Based on our results we may conclude that the spermatogenic process of P. lineatus follows the pattern of mammals with some specificity, as the process of formation of the acrosome and the presence of the perfuratorium. By other side, the simpler ultrastructure of its spermatozoon shows a pattern more closely related to the sperm cells of humans and other primates. PMID:21458280

Beguelini, Mateus R; Puga, Cintia C I; Taboga, Sebastião R; Morielle-Versute, Eliana

2011-08-01

152

AGN physics - X-raying the circumnuclear matter in the Broad Line Radio Galaxy 3C445: deep Chandra-HETG spectroscopy  

NASA Astrophysics Data System (ADS)

We will present preliminary results from the analysis of one of the deepest high resolution observation (420 ks) of a radio loud AGN. 3C445 was observed in 2011 by the Chandra HETG spectrometer as part of the GTO program. Previous X-rays observations have shown that the spectrum of 3C445 is complex. The soft band is dominated by line emission from highly ionized ions and by radiative recombination continua that may resemble the typical Narrow Line Region photoionized spectra of obscured AGNs. Recent results from Chandra LETGs data revealed that the emission lines originate instead in a gas with electron density more indicative of a Broad Line Region origin, a phenomenon that so far has been observed only in few radio quiet Seyfert 1 sources. The new deep HETG spectrum will allow us to characterize the properties of the soft X-ray emission with unprecedented detail. We will also be able to study the absorption detected in LETG data with the aim of testing the two competing models that were originally proposed to explain it (partial covering versus high-velocity ionized absorber).

Longinotti, Anna Lia; Marshall, H. L.; Guainazzi, M.; Nowak, M.; Reeves, J.; Braito, V.; Canizares, C.

2012-09-01

153

X-Raying the Ultraluminous Infrared Starburst Galaxy and Broad Absorption Line QSO Markarian 231 with Chandra  

NASA Technical Reports Server (NTRS)

With 40 ks of Clzandra ACIS-S3 exposure, new information on both the starburst and QSO components of the X-ray emission of Markarian 231, an ultraluminous infrared galaxy and broad absorption line QSO, has been obtained. The bulk of the X-ray luminosity is emitted from an unresolved nuclear point source, and the spectrum is remarkably hard, with the majority of the flux emitted above 2 keV. Most notably, significant nuclear variability (a decrease of -45% in approximately 6 hr) at energies above 2 keV indicates that Chuizdra has probed within light-hours of the central black hole. Although we concur with Maloney & Reynolds that the direct continuum is not observed, this variability coupled with the 188 eV upper limit on the equivalent width of the Fe K o emission line argues against the reflection-dominated model put forth by these authors based on their ASCA data. Instead, we favor a model in which a small, Compton-thick absorber blocks the direct X-rays, and only indirect, scattered X-rays from multiple lines of sight can reach the observer. Extended soft, thermal emission encompasses the optical extent of the galaxy and exhibits resolved structure. An off-nuclear X-ray source with a 0.35-8.0 keV luminosity of Lx = 7 x 10 sup39 ergs s sup -1 , consistent with the ultraluminous X-ray sources in other nearby starbursts, is detected. We also present an unpublished Faint Object Spectrograph spectrum from the Hirhhle Spuce Telescope archive showing the broad C IV absorption.

Gallagher, S. C.; Brandt, W. N.; Chartas, G.; Garmire, G. P.; Sambruna, R. M.

2002-01-01

154

X-ray Weak Broad-line Qquasars: Absorption or Intrinsic X-ray Weakness  

NASA Technical Reports Server (NTRS)

XMM observations of X-ray weak quasars have been performed during 2003 and 2004. The data for all the observations have become available in 2004 (there has been a delay of several months on the initial schedule, due to high background flares which contaminated the observations: as a consequence, most of them had to be rescheduled). We have reduced and analyzed all the data, and obtained interesting scientific results. Out of the eight sources, 4 are confirmed to be extremely X-ray weak, in agreement with the results of previous Chandra observations. 3 sources are confined to be highly variable both in flux (by factor 20-50) and in spectral properties (dramatic changes in spectral index). For both these groups of objects we are completing a publication: 1) For the X-ray weak sources, a paper is submitted with a complete analysis of the X-ray spectra both from Chandra and XMM-Newton, and a comparison with optical and near-IR photometry obtained from all-sky surveys. Possible models for the unusual spectral energy distribution of these sources are also presented. 2) For the variable sources, a paper is being finalized where the X-ray spectra obtained with XMM-Newton are compared with previous X-ray observations and with observations at other wavelengths. It is shown that these sources are high luminosity and extreme cases of the highly variable class of narrow-line Seyfert Is. In order to further understand the nature of these X-ray weak quasars, we submitted proposals for spectroscopy at optical and infrared telescopes. We obtained time at the TNG 4 meter telescope for near-IR observations and at the Hobby-Eberly Telescope for optical high-resolution spectroscopy. These observations have been performed in early 2004. They will complement the XMM data and will lead to understanding of whether the X-ray weakness of these sources is an intrinsic property or is due to absorption by circum-nuclear material. The infrared spectra of the variable sources have been already analyzed and are discussed in the paper by Memola et al. which will be soon submitted.

Mushotzky, Richard (Technical Monitor); Risaliti, Guida

2005-01-01

155

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

NASA Technical Reports Server (NTRS)

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 with those available in the literature, we estimate the explosion date and the peak luminosity of the SN, M(sub R) approximately equals 20.2 mag, significantly brighter than known GRB-SNe and one of the most luminous SNe Ibc ever discovered. We measure the photospheric expansion velocity of the explosion from our spectroscopic follow-up observations, v(sub ph) approximately equals 19.2 X 10 (exp 3) km/s at approx 40 days after explosion. In comparison with other broad-lined SNe, the characteristic velocity of SN2010ay is 2 - 5 X higher and similar to the measurements for GRB-SNe at comparable epochs. Moreover the velocity declines two 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 Ni-56, M(sub Ni) = 0.9(+0.1/-0.1) solar mass. Our modeling of the light-curve points to a total ejecta mass, M(sub ej) approx 4.7 Solar Mass, and total kinetic energy, E(sub K,51) approximately equals 11. Thus the ratio of M(sub Ni) to M(sub ej) is at least twice as large for SN2010ay than in GRB-SNe and may indicate an additional energy reservoir. We also measure the metallicity (log(O/H) + 12 = 8.19) of the explosion site within the host galaxy using a high S/N optical spectrum. Our abundance measurement places this SN in the low-metallicity regime populated by GRB-SNe, and approx 0.2(0.5) dex lower than that typically measured for the host environments of normal (broad-lined) Ic supernovae. Despite striking similarities to the recent GRB-SN100316D/2010bh, we show that gamma-ray observations rule out an associated GRB with E(sub gamma) approx < 6 X 10(exp 48) erg (25-150 keV). Similarly, our deep radio follow-up observations with the Expanded Very Large Array rule out relativistic ejecta with energy, E approx > 10(exp 48) erg. These observations challenge the importance of progenitor metallicity for the production of a GRB, and suggest that other parameters also play a key role.

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

2011-01-01

156

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

NASA Astrophysics Data System (ADS)

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? survey just ~4 days after explosion. The supernova (SN) had a peak luminosity, MR ? -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 Si ? 19 × 103 km s-1 at ~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 ~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 56Ni, M Ni = 0.9 M ?. Applying scaling relations to the light curve, we estimate a total ejecta mass, M ej ? 4.7 M ?, and total kinetic energy, EK ? 11 × 1051 erg. The ratio of M Ni to M ej is ~2 times as large for SN 2010ay as typical GRB-SNe and may suggest an additional energy reservoir. The metallicity (log (O/H)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 ~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 ? <~ 6 × 1048 erg (25-150 keV), and our deep radio follow-up observations with the Expanded Very Large Array rule out relativistic ejecta with energy E >~ 1048 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.; Valenti, S.; Foley, R. J.; Chornock, R.; Chomiuk, L.; Berger, E.; Smartt, S.; Hurley, K.; Barthelmy, S. D.; Levesque, E. M.; Narayan, G.; Botticella, M. T.; Briggs, M. S.; Connaughton, V.; Terada, Y.; Gehrels, N.; Golenetskii, S.; Mazets, E.; Cline, T.; von Kienlin, A.; Boynton, W.; Chambers, K. C.; Grav, T.; Heasley, J. N.; Hodapp, K. W.; Jedicke, R.; Kaiser, N.; Kirshner, R. P.; Kudritzki, R.-P.; Luppino, G. A.; Lupton, R. H.; Magnier, E. A.; Monet, D. G.; Morgan, J. S.; Onaka, P. M.; Price, P. A.; Stubbs, C. W.; Tonry, J. L.; Wainscoat, R. J.; Waterson, M. F.

2012-09-01

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

Extreme Emission Line Galaxies in CANDELS: Broad-Band Selected, Star-Bursting Dwarf Galaxies at Z greater than 1  

NASA Technical Reports Server (NTRS)

We identify an abundant population of extreme emission line galaxies (EELGs) at redshift z approx. 1.7 in the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) imaging from Hubble Space Telescope/Wide Field Camera 3 (HST/WFC3). 69 EELG candidates are selected by the large contribution of exceptionally bright emission lines to their near-infrared broad-band magnitudes. Supported by spectroscopic confirmation of strong [OIII] emission lines . with rest-frame equivalent widths approx. 1000A in the four candidates that have HST/WFC3 grism observations, we conclude that these objects are galaxies with approx.10(exp 8) Solar Mass in stellar mass, undergoing an enormous starburst phase with M*/M* of only approx. 15 Myr. These bursts may cause outflows that are strong enough to produce cored dark matter profiles in low-mass galaxies. The individual star formation rates and the co-moving number density (3.7x10(exp -4) Mpc(sup -3) can produce in approx.4 Gyr much of the stellar mass density that is presently contained in 10(exp 8) - 10(exp 9) Solar Mass dwarf galaxies. Therefore, our observations provide a strong indication that many or even most of the stars in present-day dwarf galaxies formed in strong, short-lived bursts, mostly at z > 1.

vanderWel, A.; Straughn, A. N.; Rix, H.-W.; Finkelstein, S. L.; Koekemoer, A. M.; Weiner, B. J.; Wuyts, S.; Bell, E. F.; Faber, S. M.; Trump, J. R.; Koo, D. C.; Ferguson, H. C.; Scarlata, C.; Hathi, N. P.; Dunlop, J. S.; Newman, J. A.; Dickinson, M.; Jahnke, K.; Salmon, B. W.; deMello, D. F.; Kkocevski, D. D.; Lai, K.; Grogin, N. A.; Rodney, S. A.; Guo, Yicheng

2012-01-01

159

Discovery of a broad O VIII Ly? line in the ultracompact X-ray binary 4U 1543-624  

NASA Astrophysics Data System (ADS)

We report the discovery of a broad emission feature at ˜0.7 keV in the spectra of the ultracompact X-ray binary 4U 1543-624, obtained with the high-resolution spectrographs of the XMM-Newton and Chandra satellites. We confirm the presence of the feature in the broad-band MOS2 spectrum of the source. As suggested before in the literature, the donor star in this source is a CO or ONe white dwarf, which transfers oxygen-rich material to the accretor, conceivably a neutron star. The X-rays reprocessed in this oxygen-rich accretion disc could give a reflection spectrum with O VIII Ly? as the most prominent emission line. Apart from the feature at ˜0.7 keV, we confirm the possible presence of a weak emission feature at ˜6.6 keV, which was reported in the literature for this data set. We interpret the feature at ˜0.7 and ˜6.6 keV as O VIII Ly? and Fe K? emission, respectively, caused by X-rays reflected off the accretion disc in the strong gravitational field close to the accretor.

Madej, O. K.; Jonker, P. G.

2011-03-01

160

A POSSIBLE ULTRA STRONG AND BROAD Fe K{alpha} EMISSION LINE IN SEYFERT 2 GALAXY IRAS 00521-7054  

SciTech Connect

We present XMM-Newton spectra of the Seyfert 2 Galaxy IRAS 00521-7054. A strong feature at {approx}6 keV (observer's frame) can be formally fitted with a strong (EW = 1.3 {+-} 0.3 keV in the rest frame) and broad Fe K{alpha} line, extending down to 3 keV. The underlying X-ray continuum could be fitted with an absorbed power law (with {Gamma} = 1.8 {+-} 0.2 and N{sub H} 5.9{sup +0.6}{sub -0.7} Multiplication-Sign 10{sup 22} cm{sup -2}) plus a soft component. If due to relativistically smeared reflection by an X-ray illuminated accretion disk, the spin of the supermassive black hole (SMBH) is constrained to be 0.97{sup +0.03}{sub -0.13} (errors at 90% confidence level for one interesting parameter), and the accretion system is viewed at an inclination angle of 37 Degree-Sign {+-} 4 Degree-Sign . This would be the first type 2 active galactic nucleus reported with strong red Fe K{alpha} wing detected which demands a fast rotating SMBH. The unusually large EW would suggest that the light bending effect is strong in this source. Alternatively, the spectra could be fitted by a dual-absorber model (though with a global {chi}{sup 2} higher by {approx}6 for 283 dof) with N{sub H1} 7.0 {+-} 0.8 Multiplication-Sign 10{sup 22} cm{sup -2} covering 100% of the X-ray source, and N{sub H2} = 21.7{sup +5.6}{sub -5.4} Multiplication-Sign 10{sup 22} cm{sup -2} covering 71%, which does not require an extra broad Fe K{alpha} line.

Tan, Y.; Wang, J. X.; Shu, X. W.; Zhou Youyuan, E-mail: tanyin29@mail.ustc.edu.cn, E-mail: jxw@ustc.edu.cn, E-mail: xwshu@mail.ustc.edu.cn, E-mail: yyzhou@ustc.edu.cn [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2012-03-15

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 Drosophila Broad-ComplexEarly Gene Directly Regulates Late Gene Transcription during the Ecdysone-Induced Puffing Cascade  

Microsoft Academic Search

The ensemble of tissue-specific changes that drivesDrosophilametamorphosis is initiated by the steroid hormone ecdysone and proceeds through a transcriptional cascade comprised of primary response transcriptional regulators and secondary response structural genes. TheBroad-Complex(BR-C) primary response early gene is composed of several distinct genetic functions and encodes a family of related transcription factor isoforms. Our objective in this study was to determine

Kirsten Crossgrove; Cynthia A. Bayer; James W. Fristrom; Gregory M. Guild

1996-01-01

163

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

164

1991 Annual report on scientific programs: A broad research program on the sciences of complexity  

SciTech Connect

1991 was continued rapid growth for the Santa Fe Institute (SFI) as it broadened its interdisciplinary research into the organization, evolution and operation of complex systems and sought deeply the principles underlying their dynamic behavior. 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 behavior range upwards from proteins and DNA through cells and evolutionary systems to human societies. Research models exhibiting complexity include nonlinear equations, spin glasses, cellular automata, genetic algorithms, classifier systems, and an array of other computational models. Some of the major questions facing complex systems researchers are: (1) explaining how complexity arises from the nonlinear interaction of simples 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. The importance of understanding such systems in enormous: many of the most serious challenges facing humanity--e.g., environmental sustainability, economic stability, the control of disease--as well as many of the hardest scientific questions--e.g., protein folding, the distinction between self and non-self in the immune system, the nature of intelligence, the origin of life--require deep understanding of complex systems.

Not Available

1991-01-01

165

1991 Annual report on scientific programs: A broad research program on the sciences of complexity  

SciTech Connect

1991 was continued rapid growth for the Santa Fe Institute (SFI) as it broadened its interdisciplinary research into the organization, evolution and operation of complex systems and sought deeply the principles underlying their dynamic behavior. 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 behavior range upwards from proteins and DNA through cells and evolutionary systems to human societies. Research models exhibiting complexity include nonlinear equations, spin glasses, cellular automata, genetic algorithms, classifier systems, and an array of other computational models. Some of the major questions facing complex systems researchers are: (1) explaining how complexity arises from the nonlinear interaction of simples 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. The importance of understanding such systems in enormous: many of the most serious challenges facing humanity--e.g., environmental sustainability, economic stability, the control of disease--as well as many of the hardest scientific questions--e.g., protein folding, the distinction between self and non-self in the immune system, the nature of intelligence, the origin of life--require deep understanding of complex systems.

Not Available

1991-12-31

166

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

NASA Astrophysics Data System (ADS)

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 been noted that GRB hosts are low in luminosity and low in their metal abundances. If low metallicity is sufficient to force the evolution of massive stars to end their lives as GRBs with an accompanying broad-lined SN Ic, then we would expect higher metal abundances for the broad-lined SN Ic that have no detected GRBs. This is what we observe, and this trend is independent of the choice of metallicity calibration we adopt and the mode of SN survey that found the broad-lined SN Ic. A unique feature of this analysis is that we present new spectra of the host galaxies and analyze all measurements of both samples in the same set of methods, using the galaxy emission-line measurements corrected for extinction and stellar absorption, via independent metallicity diagnostics of Kewley & Dopita, McGaugh, and Pettini & Pagel. In our small sample, the boundary between galaxies that have GRBs accompanying their broad-lined SN Ic and those that have broad-lined SN Ic without GRBs lies at an oxygen abundance of 12 + log(O/H)KD02 ~ 8.5, which corresponds to 0.2-0.6 Zsun depending on the adopted metallicity scale and solar abundance value. Even when we limit the comparison to SN Ic that were found in untargeted supernova surveys, the environment of every broad-lined SN Ic that had no GRB is more metal rich than the site of any broad-lined SN Ic where a GRB was detected. This paper includes data gathered with the MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona, and with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

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

2008-04-01

167

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

168

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

169

A high Eddington-ratio, true Seyfert 2 galaxy candidate: implications for broad-line region models  

NASA Astrophysics Data System (ADS)

A bright, soft X-ray source was detected on 2010 July 14 during an XMM-Newton slew at a position consistent with the galaxy GSN 069 (z = 0.018). Previous ROSAT observations failed to detect the source and imply that GSN 069 is now ?240 times brighter than it was in 1994 in the soft X-ray band. Optical spectra (from 2001 to 2003) are dominated by unresolved emission lines with no broad components, classifying GSN 069 as a Seyfert 2 galaxy. We report here results from a ˜1 yr monitoring with Swift and XMM-Newton, as well as from new optical spectroscopy. GSN 069 is an unabsorbed, ultrasoft source in X-rays, with no flux detected above ˜1 keV. The soft X-rays exhibit significant variability down to time-scales of hundreds of seconds. The UV-to-X-ray spectrum of GSN 069 is consistent with a pure accretion disc model which implies an Eddington ratio ? ? 0.5 and a black hole mass of ? 1.2 × 106 M?. A new optical spectrum, obtained ˜3.5 months after the XMM-Newton slew detection, is consistent with earlier spectra and lacks any broad-line component. The lack of cold X-ray absorption and the short time-scale variability in the soft X-rays rule out a standard Seyfert 2 interpretation of the source. The present Eddington ratio of GSN 069 exceeds the critical value below which no emitting broad-line region (BLR) forms, according to popular models, so that GSN 069 can be classified as a bona-fide high Eddington-ratio true Seyfert 2 galaxy. We discuss our results within the framework of two possible scenarios for the BLR in AGN, namely the two-phase model (cold BLR clouds in pressure equilibrium with a hotter medium), and models in which the BLR is part of an outflow, or disc-wind. Finally, we point out that GSN 069 may be a member of a population of super-soft active galactic nuclei (AGN) whose spectral energy distribution is completely dominated by accretion disc emission, as it is the case in some black hole X-ray binary transients during their outburst evolution. The disc emission for a typical AGN with black hole mass of 107-108 M? does not enters the soft X-ray band, so that GSN 069-like objects with larger black hole mass (i.e. the bulk of the AGN population) are missed by current X-ray surveys, or misclassified as Compton-thick candidates. If the analogy between black hole X-ray binary transients and AGN holds, the lifetime of these super-soft states in AGN may be longer than 104 years, implying that the actual population of super-soft AGN may not be negligible, possibly contaminating the estimated fraction of heavily obscured AGN from current X-ray surveys.

Miniutti, G.; Saxton, R. D.; Rodríguez-Pascual, P. M.; Read, A. M.; Esquej, P.; Colless, M.; Dobbie, P.; Spolaor, M.

2013-08-01

170

Constraining Sub-parsec Binary Supermassive Black Holes in Quasars with Multi-epoch Spectroscopy. II. The Population with Kinematically Offset Broad Balmer Emission Lines  

NASA Astrophysics Data System (ADS)

A small fraction of quasars have long been known to show bulk velocity offsets (of a few hundred to thousands of km s–1) in the broad Balmer lines with respect to the systemic redshift of the host galaxy. Models to explain these offsets usually invoke broad-line region gas kinematics/asymmetry around single black holes (BHs), orbital motion of massive (~sub-parsec (sub-pc)) binary black holes (BBHs), or recoil BHs, but single-epoch spectra are unable to distinguish between these scenarios. The line-of-sight (LOS) radial velocity (RV) shifts from long-term spectroscopic monitoring can be used to test the BBH hypothesis. We have selected a sample of 399 quasars with kinematically offset broad H? lines from the Sloan Digital Sky Survey (SDSS) Seventh Data Release quasar catalog, and have conducted second-epoch optical spectroscopy for 50 of them. Combined with the existing SDSS spectra, the new observations enable us to constrain the LOS RV shifts of broad H? lines with a rest-frame baseline of a few years to nearly a decade. While previous work focused on objects with extreme velocity offset (>103 km s–1), we explore the parameter space with smaller (a few hundred km s–1) yet significant offsets (99.7% confidence). Using cross-correlation analysis, we detect significant (99% confidence) radial accelerations in the broad H? lines in 24 of the 50 objects, of ~10-200 km s–1 yr–1 with a median measurement uncertainty of ~10 km s–1 yr–1, implying a high fraction of variability of the broad-line velocity on multi-year timescales. We suggest that 9 of the 24 detections are sub-pc BBH candidates, which show consistent velocity shifts independently measured from a second broad line (either H? or Mg II) without significant changes in the broad-line profiles. Combining the results on the general quasar population studied in Paper I, we find a tentative anti-correlation between the velocity offset in the first-epoch spectrum and the average acceleration between two epochs, which could be explained by orbital phase modulation when the time separation between two epochs is a non-negligible fraction of the orbital period of the motion causing the line displacement. We discuss the implications of our results for the identification of sub-pc BBH candidates in offset-line quasars and for the constraints on their frequency and orbital parameters. Based, in part, on data obtained at the MMT, ARC 3.5 m, and FLWO 1.5 m Telescopes.

Liu, Xin; Shen, Yue; Bian, Fuyan; Loeb, Abraham; Tremaine, Scott

2014-07-01

171

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

172

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

173

Nustar Reveals an Intrinsically X-ray Weak Broad Absorption Line Quasar in the Ultraluminous Infrared Galaxy Markarian 231  

NASA Technical Reports Server (NTRS)

We present high-energy (3-30 keV) NuSTAR observations of the nearest quasar, the ultraluminous infrared galaxy (ULIRG) Markarian 231 (Mrk 231), supplemented with new and simultaneous low-energy (0.5-8 keV) data from Chandra. The source was detected, though at much fainter levels than previously reported, likely due to contamination in the large apertures of previous non-focusing hard X-ray telescopes. The full band (0.5-30 keV) X-ray spectrum suggests the active galactic nucleus (AGN) in Mrk 231 is absorbed by a patchy and Compton-thin N(sub H) approx. 1.2(sup +0.3) sub-0.3) x 10(exp 23) / sq cm) column. The intrinsic X-ray luminosity L(sub 0.5-30 Kev) approx. 1.0 x 10(exp 43) erg /s) is extremely weak relative to the bolometric luminosity where the 2-10 keV to bolometric luminosity ratio is approx. 0.03% compared to the typical values of 2-15%. Additionally, Mrk 231 has a low X-ray-to-optical power law slope alpha(sub 0X) approx. -1.7. It is a local example of a low-ionization broad absorption line (LoBAL) quasar that is intrinsically X-ray weak. The weak ionizing continuum may explain the lack of mid-infrared [O IV], [Ne V], and [Ne VI] fine-structure emission lines which are present in sources with otherwise similar AGN properties. We argue that the intrinsic X-ray weakness may be a result of the super-Eddington accretion occurring in the nucleus of this ULIRG, and may also be naturally related to the powerful wind event seen in Mrk 231, a merger remnant escaping from its dusty cocoon.

Teng, Stacy H.; Brandt. W. N.; Harrison, F. A.; Luo, B.; Alexander, D. M.; Bauer, F. E.; Boggs, S. E.; Christensen, F. E.; Comastri, A.; Craig, W. W.; Fabian, A. C.; Farrah, D.; Fiore, F.; Gandhi, P.; Grefenstette, B. W.; Hailey, C. J.; Hickox, R. C.; Madsen, K. K.; Ptak, A. F.; Rigby, Jane Rebecca; Risaliti, G.; Saz, C.; Stern, D.; Veilleux, S.; Walton, D. J.; Wik, D. R.; Zhang, W. W.

2014-01-01

174

The Lick AGN Monitoring Project 2011: Dynamical Modeling of the Broad-line Region in Mrk 50  

NASA Astrophysics Data System (ADS)

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+1.2 -0.9 light days, a width of the BLR of 6.9+1.2 -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+7 -5 deg, close to face-on. Finally, the black hole mass of Mrk 50 is inferred to be log10(M BH/M ?) = 7.57+0.44 -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 log10 f = 0.78+0.44 -0.27, consistent with the commonly adopted mean value of 0.74 based on aligning the M BH-?* 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; Barth, Aaron J.; Bennert, Vardha N.; Canalizo, Gabriela; Filippenko, Alexei V.; Gates, Elinor L.; Greene, Jenny E.; Li, Weidong; Malkan, Matthew A.; Sand, David J.; Stern, Daniel; Woo, Jong-Hak; Assef, Roberto J.; Bae, Hyun-Jin; Buehler, Tabitha; Cenko, S. Bradley; Clubb, Kelsey I.; Cooper, Michael C.; Diamond-Stanic, Aleksandar M.; Hiner, Kyle D.; Hönig, Sebastian F.; Joner, Michael D.; Kandrashoff, Michael T.; Laney, C. David; Lazarova, Mariana S.; Nierenberg, A. M.; Park, Dawoo; Silverman, Jeffrey M.; Son, Donghoon; Sonnenfeld, Alessandro; Thorman, Shawn J.; Tollerud, Erik J.; Walsh, Jonelle L.; Walters, Richard

2012-07-01

175

High-resolution line-shape spectroscopy during a laser pulse based on Dual-Broad-Band-CARS interferometry  

SciTech Connect

A high-resolution spectroscopic method is developed for recording Raman spectra of molecular transitions in transient objects during a laser pulse with a resolution of {approx}0.1 cm{sup -1}. The method is based on CARS spectroscopy using a Fabry-Perot interferometer for spectral analysis of the CARS signal and detecting a circular interferometric pattern on a two-dimensional multichannel photodetector. It is shown that the use of the Dual-Broad-Band-CARS configuration to obtain the CARS process provides the efficient averaging of the spectral-amplitude noise of the CARS signal generated by a laser pulse and, in combination with the angular integration of the two-dimensional interference pattern, considerably improves the quality of interferograms. The method was tested upon diagnostics of the transient oxygen-hydrogen flame where information on the shapes of spectral lines of the Q-branch of hydrogen molecules required for measuring temperature was simultaneously obtained and used. (special issue devoted to the 90th anniversary of a.m. prokhorov)

Vereschagin, Konstantin A; Vereschagin, Alexey K; Smirnov, Valery V; Stelmakh, O M; Fabelinskii, V I [A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Clauss, W; Klimenko, D N; Oschwald, M, E-mail: veresch@kapella.gpi.r, E-mail: Al_Vereshchagin@mail.r, E-mail: vvs@kapella.gpi.r, E-mail: stelmakh@kapella.gpi.r [German Aerospace Research Centre, DLR, Hardthausen (Germany)

2006-07-31

176

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

177

On-Line QRS Complex Detection Using Wavelet Filtering.  

National Technical Information Service (NTIS)

This paper presents a new QRS complex detection algorithm that can be applied in various on-line FCC processing systems The algorithm is performed in two steps: first a wavelet transform filtering is applied to the signal, then QRS complex localization is...

L. Szilagyi Z. Benyo S. M. Szilagyi L. Nagy

2001-01-01

178

On-line QRS complex detection using wavelet filtering  

Microsoft Academic Search

This paper presents a new QRS complex detection algorithm that can be applied in various on-line ECG processing systems. The algorithm is performed in two steps: first a wavelet transform filtering is applied to the signal, then QRS complex localization is performed using a maximum detection and peak classification algorithm. The algorithm has been tested in two phases. First QRS

L. Szilagyi; Z. Benyo; S. M. Szilagyi; A. Szlavecz; L. Nagy

2001-01-01

179

Broad-band characterization of the complex permittivity and permeability of materials  

SciTech Connect

By employment of state-of-the-art Vector Network Analyzers, and other wide-band measurement equipment and techniques, the authors have the capability of measuring the complex permittivity and permeability of materials, for frequencies ranging from several tens of Kilohertz up to several Gigahertz. Measurement methods and equations for numerical determination are based on recommendations by the National Institute of Standards and Technology (NIST). Types of materials which can be analyzed are dielectric or magnetic RF and radar absorbers; thin sheets, paints, coatings; castable resins; foams and low density materials; ceramics and ferrites; carbonized fabrics; and composites.

Avalle, C.A. [Lawrence Livermore National Lab., CA (United States). Electromagnetics and Diagnostics Group

1994-11-01

180

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

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

Unveiling the Intrinsic X-Ray Properties of Broad Absorption Line Quasars with a Relatively Unbiased Sample  

NASA Astrophysics Data System (ADS)

There is growing evidence of a higher intrinsic fraction of broad absorption line quasars (BALQSOs) than that obtained in optical surveys, on which most previous X-ray studies of BALQSOs have focused. Here we present Chandra observations of 18 BALQSOs at z ~ 2, selected from a near-infrared (Two Micron All Sky Survey) sample, where the BALQSO fraction is likely to be close to the intrinsic fraction. We measure photon indices using the stacked spectra of the optically faint (i – Ks >= 2.3 mag) and optically bright (i – Ks < 2.3 mag) samples to be ? ~= 1.5-2.1. We constrain their intrinsic column density by modeling the X-ray fractional hardness ratio, finding a mean column density of 3.5 × 1022 cm–2 assuming neutral absorption. We incorporate Sloan Digital Sky Survey optical measurements (rest frame UV) to study the broadband spectral index between the X-ray and UV bands, and compare this to a large sample of normal quasars. We estimate that the optically faint BALQSOs are X-ray weaker than the optically bright ones, and the entire sample of BALQSOs are intrinsically X-ray weak when compared to normal active galactic nuclei (AGNs). Correcting for magnification of X-ray emission via gravitational lensing by the central black hole viewed at large inclination angles makes these BALQSOs even more intrinsically X-ray weak. Finally, we estimate AGN kinetic feedback efficiencies of a few percent for an X-ray wind of 0.3c in high-ionization BALQSOs. Combined with energy carried by low-ionization BALQSOs and UV winds, the total kinetic energy in BALQSOs can be sufficient to provide AGN kinetic feedback required to explain the co-evolution between black holes and host galaxies.

Morabito, Leah K.; Dai, Xinyu; Leighly, Karen M.; Sivakoff, Gregory R.; Shankar, Francesco

2014-05-01

183

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

184

J-Band Spectroscopy of the z = 5.74 Broad Absorption Line Quasar SDSSp J104433.04-012502.2  

Microsoft Academic Search

We use NIRSPEC, a near-IR spectrometer on Keck II, to obtain moderate-resolution (R=1540) spectroscopy that shows conclusively that the C IV emission line in the z=5.74 quasar SDSSp J104433.04-012502.2 is accompanied by broad, blueshifted C IV absorption. The line has a ``balnicity index'' of 900 km s-1 and a rest-frame equivalent width of 13.1+\\/-1.3 Å relative to the continuum. This

R. W. Goodrich; R. Campbell; F. H. Chaffee; G. M. Hill; D. Sprayberry; W. N. Brandt; D. P. Schneider; S. Kaspi; X. Fan; J. E. Gunn; M. A. Strauss

2001-01-01

185

Broad and complex antifungal activity among environmental isolates of lactic acid bacteria.  

PubMed

More than 1200 isolates of lactic acid bacteria isolated from different environments were screened for antifungal activity in a dual-culture agar plate assay. Approximately 10% of the isolates showed inhibitory activity and 4% showed strong activity against the indicator mould Aspergillus fumigatus. The antifungal spectra for 37 isolates with strong activity and five isolates with low or no activity were determined. Several of the strains showed strong inhibitory activity against the moulds A. fumigatus, Aspergillus nidulans, Penicillium commune and Fusarium sporotrichioides, and also against the yeast Rhodotorula mucilaginosa. Penicillium roqueforti and the yeasts Pichia anomala and Kluyveromyces marxianus were not inhibited. Several isolates showed reduced antifungal activity after storage and handling. The majority of the fungal inhibitory isolates were identified by 16S rDNA sequencing as Lactobacillus coryniformis. Lactobacillus plantarum and Pediococcus pentosaceus were also frequently identified among the active isolates. The degree of fungal inhibition was not only related to production of lactic or acetic acid. In addition, antifungal cyclic dipeptides were identified after HPLC separation and several other active fractions were found suggesting a highly complex nature of the antifungal activity. PMID:12594034

Magnusson, Jesper; Ström, Katrin; Roos, Stefan; Sjögren, Jörgen; Schnürer, Johan

2003-02-14

186

Cytoplasmic ribonucleoprotein complexes containing human LINE-1 protein and RNA.  

PubMed Central

P40 is the protein encoded by the first open reading frame (ORF1) of the human LINE-1 (L1Hs) retrotransposon; it is 338 amino acids long, has a leucine zipper motif and has been found in human teratocarcinoma cell lines and some tumor cells. In this report, we describe properties of p40 in the human teratocarcinoma cell lines NTera2D1 and 2102Ep. The results indicate that: (i) most of p40 occurs in large multimeric cytoplasmic complexes, (ii) L1Hs RNA is associated with the p40 complexes, (iii) the complexes are dissociated by ribonuclease and (iv) p40 is a novel RNA-binding protein. Cross-linking experiments with full-length and truncated p40 produced in Escherichia coli also showed that: (i) p40 itself can form a multimeric complex larger than 250 kDa, (ii) the leucine zipper motif and the region conserved among the predicted ORF1 polypeptides of mammalian LINE-1s participate in complex formation and (iii) the amino terminal region is important for the stability of complex formation. Analysis of the amino acid sequence of p40 suggests that long segments of the molecule can assume an alpha-helical configuration including the leucine zipper and the conserved region. The evidence presented here suggests that the p40 complex is a ribonucleoprotein complex containing L1Hs RNA(s) and that protein-protein interactions in which alpha-helix structures participate, for example coiled-coils, may occur in the complex. Images

Hohjoh, H; Singer, M F

1996-01-01

187

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

2013-12-01

188

Broad-range real-time PCR assay for the rapid identification of cell-line contaminants and clinically important mollicute species  

Microsoft Academic Search

Polymerase chain reaction assays have become widely used methods of confirming the presence of Mollicutes species in clinical samples and cell cultures. We have developed a broad-range real-time PCR assay using the locked nucleic acid technology to detect mollicute species causing human infection and cell line contamination. Primers and probes specifically for the conserved regions of the mycoplasmal tuf gene

Melanie Störmer; Tanja Vollmer; Birgit Henrich; Knut Kleesiek; Jens Dreier

2009-01-01

189

The Broad-Complex directly controls a tissue-specific response to the steroid hormone ecdysone at the onset of Drosophila metamorphosis.  

PubMed Central

In Drosophila, all of the major metamorphic transitions are regulated by changes in the titer of the steroid hormone ecdysone. Here we examine how a key regulator of metamorphosis and primary ecdysone response gene, the Broad-Complex, transmits the hormonal signal to one of its targets, the Sgs-4 glue gene. We show that Broad-Complex RNAs accumulate in mid third instar larval salivary glands prior to Sgs-4 induction, as expected for the products of a gene that regulates the timing of Sgs-4 activation. The Broad-Complex codes for a family of zinc finger transcriptional regulators. We have identified a number of binding sites for these proteins in sequences known to regulate the timing of Sgs-4 induction, and have used these sites to derive a binding consensus for each protein. Some of these binding sites are required in vivo for Sgs-4 activity. In addition, rbp+, a genetically defined Broad-Complex function that is required for Sgs-4 induction, acts through these Broad-Complex binding sites. Thus, the Broad-Complex directly mediates a temporal and tissue-specific response to ecdysone as larvae become committed to metamorphosis. Images

von Kalm, L; Crossgrove, K; Von Seggern, D; Guild, G M; Beckendorf, S K

1994-01-01

190

The Broad-Complex directly controls a tissue-specific response to the steroid hormone ecdysone at the onset of Drosophila metamorphosis.  

PubMed

In Drosophila, all of the major metamorphic transitions are regulated by changes in the titer of the steroid hormone ecdysone. Here we examine how a key regulator of metamorphosis and primary ecdysone response gene, the Broad-Complex, transmits the hormonal signal to one of its targets, the Sgs-4 glue gene. We show that Broad-Complex RNAs accumulate in mid third instar larval salivary glands prior to Sgs-4 induction, as expected for the products of a gene that regulates the timing of Sgs-4 activation. The Broad-Complex codes for a family of zinc finger transcriptional regulators. We have identified a number of binding sites for these proteins in sequences known to regulate the timing of Sgs-4 induction, and have used these sites to derive a binding consensus for each protein. Some of these binding sites are required in vivo for Sgs-4 activity. In addition, rbp+, a genetically defined Broad-Complex function that is required for Sgs-4 induction, acts through these Broad-Complex binding sites. Thus, the Broad-Complex directly mediates a temporal and tissue-specific response to ecdysone as larvae become committed to metamorphosis. PMID:8062827

von Kalm, L; Crossgrove, K; Von Seggern, D; Guild, G M; Beckendorf, S K

1994-08-01

191

Conversion of complex contour line definitions into polygonal element mosaics  

Microsoft Academic Search

A simple algorithm is presented for processing complex contour arrangements to produce polygonal element mosaics which are suitable for line drawing and continuous tone display. The program proceeds by mapping adjacent contours onto the same unit square and, subject to ordering limitations, connecting nodes of one contour to their nearest neighbors in the other contour. While the mapping procedure provides

H. N. Christiansen; T. W. Sederberg

1978-01-01

192

The complexity of understanding line drawings of origami scenes  

Microsoft Academic Search

This paper deals with the interpretation of line drawings of Origami scenes(Kanade, 1980), that is scenes obtained by assembling planar panels of negligiblethickness, and it addresses the computational complexity of the problemof consistently assigning suitable labels to the segments describing 3D propertiesas convexity, concavity and occlusion (labeling problem). The mainresults of the paper are the following: (a) the labeling problem

Pietro Parodi

1996-01-01

193

A three-line lateral flow assay strip for the measurement of C-reactive protein covering a broad physiological concentration range in human sera.  

PubMed

The lateral flow assay (LFA) strip sensor possesses many advantages as a diagnostic device, including the capabilities of rapid, one-step assay performance, and high throughput production. A major limitation of the sensor, however, is its difficulty in measuring a broad concentration range of target proteins, including C-reactive protein (CRP), due to the "hook effect." In this study, we report the use of a three-line LFA strip sensor, adding an antigen line to the conventional two-line LFA sensor, for detecting CRP within a broad concentration range in human sera. We introduced an antigen line between test and control lines in the LFA sensor. The antigen line was formed by dispensing a CRP antibody solution followed by a CRP solution in nitrocellulose membrane. All other conditions were identical to those applied to the conventional LFA strip sensor. The CRP level in test samples was generated by data processing from the intensities of three lines. The strip sensor measured a linear detection range of CRP concentration from 1ng/mL to 500?g/mL within 10min, with a calculated detection range of 0.69ng/mL-1.02mg/mL. Using the developed three-line LFA sensor, 50 clinical samples were measured at a detection range of 0.4-84.7?g/mL. This novel and easy-to-use CRP sensor can be a useful tool for rapid, sensitive, and cost-effective detection of a broad physiological concentration range of CRP capabilities that are vital for various diagnostic applications. PMID:24906087

Oh, Young Kyoung; Joung, Hyou-Arm; Han, Hyung Soo; Suk, Ho-Jun; Kim, Min-Gon

2014-11-15

194

RELATIVISTIC PLASMA AS THE DOMINANT SOURCE OF THE OPTICAL CONTINUUM EMISSION IN THE BROAD-LINE RADIO GALAXY 3C 120  

SciTech Connect

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 {approx}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.

Leon-Tavares, J.; Lobanov, A. P.; Arshakian, T. G. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany); Chavushyan, V. H. [Instituto Nacional de Astrofisica Optica y Electronica, Apartado Postal 51 y 216, 72000 Puebla (Mexico); Doroshenko, V. T. [Crimean Laboratory of the Sternberg Astronomical Institute, P/O Nauchny, Crimea 98409 (Ukraine); Sergeev, S. G.; Efimov, Y. S.; Nazarov, S. V., E-mail: leon@kurp.hut.f [Crimean Astrophysical Observatory, P/O Nauchny, Crimea 98409 (Ukraine)

2010-05-20

195

Broad-range PCR-TTGE for the first-line detection of bacterial pathogen DNA in ticks  

Microsoft Academic Search

Ticks are known or suspected vectors for a wide range of bacterial pathogens. One of the first steps for tick-borne risk assessment is the detection of these pathogens in their vectors. In the present study, a broad-range PCR amplification of the eubacterial gene encoding the 16S rRNA gene combined with Temporal Temperature Gradient gel Electrophoresis (TTGE) was evaluated as a

Lénaïg Halos; Maria Mavris; Gwenaël Vourc’h; Renaud Maillard; Jacques Barnouin; Henri-Jean Boulouis; Muriel Vayssier-Taussat

2006-01-01

196

Quantum complex sine-Gordon model on a half line  

NASA Astrophysics Data System (ADS)

In this paper, we examine the quantum complex sine-Gordon model on a half line. We obtain the quantum spectrum of boundary bound states using the the semi-classical method of Dashen, Hasslacher and Neveu. The results are compared and found to agree with the bootstrap programme. A particle/soliton reflection factor is conjectured, which is consistent with unitary, crossing and our semi-classical results.

Bowcock, Peter; Tzamtzis, Georgios

2007-11-01

197

Role of emission angular directionality in spin determination of accreting black holes with a broad iron line  

NASA Astrophysics Data System (ADS)

Aims: The spin of an accreting black hole can be determined by spectroscopy of the emission and absorption features produced in the inner regions of an accretion disc. In this work, we discuss the method employing the relativistic line profiles of iron in the X-ray domain, where the emergent spectrum is blurred by general relativistic effects. Methods: Precision of the spectra fitting procedure could be compromised by inappropriate accounting for the angular distribution of the disc emission. Often a unique profile is assumed, invariable over the entire range of radii in the disc and energy in the spectral band. An isotropic distribution or a particular limb-darkening law have been frequently set, although some radiation transfer computations exhibit an emission excess towards the grazing angles (i.e., the limb brightening). By assuming a rotating black hole in the centre of an accretion disc, we perform radiation transfer computations of an X-ray irradiated disc atmosphere (NOAR code) to determine the directionality of outgoing X-rays in the 2-10 keV energy band. Based on these computations, we produce a new extension to the KY software package for X-ray spectra fitting of relativistic accretion discs. Results: We study how sensitive the spin determination is to the assumptions about the intrinsic angular distribution of the emitted photons. The uncertainty of the directional emission distribution translates to ?20% uncertainty in the determination of the marginally stable orbit. We implemented the simulation results as a new extension to the KY software package for X-ray spectra fitting of relativistic accretion disc models. Although the parameter space is rather complex, leading to a rich variety of possible outcomes, we find that on average the isotropic directionality reproduces our model data to the best precision. Our results also suggest that an improper use of limb darkening can partly mimic a steeper profile of radial emissivity. We demonstrate these results in the case of XMM-Newton observation of the Seyfert galaxy MCG-6-30-15, for which we construct confidence levels of ?2 statistics, and on the simulated data for the future X-ray IXO mission. Our simulations, with the tentative IXO response, show a significant improvement that can qualitatively enhance the accuracy of spin determination.

Svoboda, J.; Dov?iak, M.; Goosmann, R.; Karas, V.

2009-11-01

198

Ecdysone response elements in the distal promoter of the Bombyx Broad-Complex gene, BmBR-C.  

PubMed

The Bombyx mori silkworm's homologue of the Broad-Complex gene (BmBR-C) is transcribed from two promoters: a distal promoter (Pdist) and a proximal promoter (Pprox). As determined by a luciferase assay, the transcriptional activity of Pdist, but not Pprox, was activated by ecdysone. Further analyses using reporters driven by sequential deletion Pdist mutants indicated that two regions, ecdysone responsive element (EcRE)-D and EcRE-P, -4950 bp and -3480 bp upstream from the distal transcription start site, respectively, were important in the responsiveness of Pdist to 20-hydroxyecdysone (20E); however, no significant sequence similarities were found between the canonical EcRE and the EcRE-D or EcRE-P regions. Electrophoretic mobility shift assays showed that both the EcRE-D and -P sequences specifically bound to Bombyx protein(s). Sequence analyses and competition assays suggested that the protein(s) bound to EcRE-P might include components other than the ecdysone receptor (EcR), suggesting that BmBR-C transcription was indirectly activated by ecdysone through the EcRE-P. Remarkably, protein binding to the mid-region of the EcRE-D, EcRE-Db, was competitively inhibited by an oligonucleotide containing the Drosophila hsp27 EcRE sequence. Furthermore, an anti-EcR antibody interfered with the formation of the protein-EcRE-Db complex. These results indicated that a functional Bombyx ecdysone receptor binds to EcRE-D and activates the expression of BmBR-C. PMID:24576019

Nishita, Y

2014-06-01

199

Newly Cultured Bacteria with Broad Diversity Isolated from Eight-Week Continuous Culture Enrichments of Cow Feces on Complex Polysaccharides  

PubMed Central

One of the functions of the mammalian large intestinal microbiota is the fermentation of plant cell wall components. In ruminant animals, the majority of their nutrients are obtained via pregastric fermentation; however, up to 20% can be recovered from microbial fermentation in the large intestine. Eight-week continuous culture enrichments of cattle feces with cellulose and xylan-pectin were used to isolate bacteria from this community. A total of 459 bacterial isolates were classified phylogenetically using 16S rRNA gene sequencing. Six phyla were represented: Firmicutes (51.9%), Bacteroidetes (30.9%), Proteobacteria (11.1%), Actinobacteria (3.5%), Synergistetes (1.5%), and Fusobacteria (1.1%). The majority of bacterial isolates had <98.5% identity to cultured bacteria with sequences in the Ribosomal Database Project and thus represent new species and/or genera. Within the Firmicutes isolates, most were classified in the families Lachnospiraceae, Ruminococcaceae, Erysipelotrichaceae, and Clostridiaceae I. The majority of the Bacteroidetes were most closely related to Bacteroides thetaiotaomicron, B. ovatus, and B. xylanisolvens and members of the Porphyromonadaceae family. Many of the Firmicutes and Bacteroidetes isolates were related to species demonstrated to possess enzymes which ferment plant cell wall components; the others were hypothesized to cross-feed these bacteria. The microbial communities that arose in these enrichment cultures had broad bacterial diversity. With over 98% of the isolates not represented as previously cultured, there are new opportunities to study the genomic and metabolic capacities of these members of the complex intestinal microbiota.

2014-01-01

200

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

2012-09-01

201

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

202

THE STRUCTURE OF THE BROAD-LINE REGION IN ACTIVE GALACTIC NUCLEI. I. RECONSTRUCTED VELOCITY-DELAY MAPS  

SciTech Connect

We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum entropy method for four objects: Mrk 335, Mrk 1501, 3C 120, and PG 2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different velocity bins of the H{beta} emission line. The four velocity-delay maps show unique dynamical signatures for each object. For 3C 120, the Balmer lines show kinematic signatures consistent with both an inclined disk and infalling gas, but the He II {lambda}4686 emission line is suggestive only of inflow. The Balmer lines in Mrk 335, Mrk 1501, and PG 2130+099 show signs of infalling gas, but the He II emission in Mrk 335 is consistent with an inclined disk. We also see tentative evidence of combined virial motion and infalling gas from the velocity-binned analysis of Mrk 6. The maps for 3C 120 and Mrk 335 are two of the most clearly defined velocity-delay maps to date. These maps constitute a large increase in the number of objects for which we have resolved velocity-delay maps and provide evidence supporting the reliability of reverberation-based black hole mass measurements.

Grier, C. J.; Peterson, B. M.; Pogge, R. W.; De Rosa, G.; Martini, Paul; Kochanek, C. S.; Zu, Y.; Shappee, B.; Beatty, T. G.; Salvo, C. Araya; Bird, J. C. [Department of Astronomy, The Ohio State University, 140 W 18th Ave, Columbus, OH 43210 (United States)] [Department of Astronomy, The Ohio State University, 140 W 18th Ave, Columbus, OH 43210 (United States); Horne, Keith [SUPA Physics and Astronomy, University of St. Andrews, Fife, KY16 9SS Scotland (United Kingdom)] [SUPA Physics and Astronomy, University of St. Andrews, Fife, KY16 9SS Scotland (United Kingdom); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, One Park Place South SE, Suite 700, Atlanta, GA 30303 (United States)] [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, One Park Place South SE, Suite 700, Atlanta, GA 30303 (United States); Denney, K. D. [Marie Curie Fellow at the Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark)] [Marie Curie Fellow at the Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Siverd, R. [Department of Physics and Astronomy, Vanderbilt University, 5301 Stevenson Center, Nashville, TN 37235 (United States)] [Department of Physics and Astronomy, Vanderbilt University, 5301 Stevenson Center, Nashville, TN 37235 (United States); Sergeev, S. G.; Borman, G. A. [Crimean Astrophysical Observatory, P/O Nauchny Crimea 98409 (Ukraine)] [Crimean Astrophysical Observatory, P/O Nauchny Crimea 98409 (Ukraine); Kaspi, S. [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel)] [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Bord, D. J. [Department of Natural Sciences, The University of Michigan - Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128 (United States)] [Department of Natural Sciences, The University of Michigan - Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128 (United States); Che, X. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 41809 (United States)] [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 41809 (United States); and others

2013-02-10

203

Broad and shifted iron-group emission lines in -ray bursts as tests of the hypernova scenario  

Microsoft Academic Search

In the hypernova\\/collapsar model of -ray bursts, it is natural that radiation is emitted by the inner engine for some time after the burst. This has been discussed as a possible source of the X-ray line emission observed in some afterglows. We show here that the natural geometry of a hypernova -a source of radiation at the bottom of a

G. C. McLaughlin; R. A. M. J. Wijers; G. E. Brown; H. A. Bethe

204

Broad spectrum and potent antitumor activities of YM155, a novel small-molecule survivin suppressant, in a wide variety of human cancer cell lines and xenograft models.  

PubMed

Antitumor activities of YM155, a novel small-molecule survivin suppressant, were investigated in a wide variety of human cancer cell lines and xenograft models. YM155 inhibited the growth of 119 human cancer cell lines, with the greatest activity in lines derived from non-Hodgkin's lymphoma, hormone-refractory prostate cancer, ovarian cancer, sarcoma, non-small-cell lung cancer, breast cancer, leukemia and melanoma. The mean log growth inhibition of 50% (GI(50) ) value was 15 nM. The mean GI(50) values of YM155 were 11 nM for p53 mut/null cell lines and 16 nM for p53 WT cell lines, suggesting that YM155 inhibits the growth of human tumor cell lines regardless of their p53 status. In non-small-cell lung cancer (Calu 6, NCI-H358), melanoma (A375), breast cancer (MDA-MB-231) and bladder cancer (UM-UC-3) xenograft models, 3- or 7-day continuous infusions of YM155 (1-10 mg/kg) demonstrated significant antitumor activity without showing significant bodyweight loss. Tumor regressions induced by YM155 were associated with reduced intratumoral survivin expression levels, increased apoptosis and decreased mitotic indices. The broad and potent antitumor activity presented in the present study is indicative of the therapeutic potential of YM155 in the clinical setting. PMID:21205082

Nakahara, Takahito; Kita, Aya; Yamanaka, Kentaro; Mori, Masamichi; Amino, Nobuaki; Takeuchi, Masahiro; Tominaga, Fumiko; Kinoyama, Isao; Matsuhisa, Akira; Kudou, Masafumi; Sasamata, Masao

2011-03-01

205

Evidence for a Circum-Nuclear and Ionised Absorber in the X-ray Obscured Broad Line Radio Galaxy 3C 445  

NASA Technical Reports Server (NTRS)

Here we present the results of a Suzaku observation of the Broad Line Radio Galaxy 3C 445. We confirm the results obtained with the previous X-ray observations which unveiled the presence of several soft X-ray emission lines and an overall X-ray emission which strongly resembles a typical Seyfert 2 despite of the optical classification as an unobscured AGN. The broad band spectrum allowed us to measure for the first time the amount of reflection (R approximately 0.9) which together with the relatively strong neutral Fe Ka emission line (EW approximately 100 eV) strongly supports a scenario where a Compton-thick mirror is present. The primary X ray continuum is strongly obscured by an absorber with a column density of NH = 2 - 3 x 10(exp 23) per square centimeter. Two possible scenarios are proposed for the absorber: a neutral partial covering or a mildly ionised absorber with an ionisation parameter log xi approximately 1.0 erg centimeter per second. A comparison with the past and more recent X-ray observations of 3C 445 performed with XMM-Newton and Chandra is presented, which provided tentative evidence that the ionised and outflowing absorber varied. We argue that the absorber is probably associated with an equatorial diskwind located within the parsec scale molecular torus.

Braito, V.; Reeves, J. N.; Sambruna, R. M.; Gofford, J.

2012-01-01

206

Broad and Shifted Iron-Group Emission Lines in Gamma-Ray Bursts as Tests of the Hypernova Scenario  

Microsoft Academic Search

In the hypernova\\/collapsar model of gamma-ray bursts, it is natural that radiation is emitted by the inner engine for some time after the burst. This has been discussed as a possible source of the X-ray line emission observed in some afterglows. We show here that the natural geometry of a hypernova-a source of radiation at the bottom of a deep

G. C. McLaughlin; R. A. M. J. Wijers; G. E. Brown; H. A. Bethe

2002-01-01

207

Broad and shifted iron-group emission lines in gamma-ray bursts as tests of the hypernova scenario  

Microsoft Academic Search

In the hypernova\\/collapsar model of gamma-ray bursts, it is natural that\\u000aradiation is emitted by the inner engine for some time after the burst. This\\u000ahas been discussed as a possible source of the X-ray line emission observed in\\u000asome afterglows. We show here that the natural geometry of a hypernova\\u000a --a source of radiation at the bottom of a

G. C. McLaughlin; R. A. M. J. Wijers; G. E. Brown; H. A. Bethe

2001-01-01

208

Phase-Dependent Observations of Intermediate Polars and The Broad Emission and Absorption Line Region in NGC 3516  

NASA Technical Reports Server (NTRS)

The Intermediate Polars (IP's) constitute a class of Cataclysmic Variables (CV's), which are binary star systems in which mass is transferred from a late-type main-sequence star to a white dwarf via Roche lobe overflow. In the IP's, the inner accretion disk is evidently disrupted by the magnetic field of the white dwarf. High-temperature shocks at the white dwarf's magnetic poles (where accretion occurs) produce X-rays, which are reprocessed into photons over a broad energy band across the electromagnetic spectrum. Because the white dwarf typically spins rapidly (rotation periods a few 10s to a few 100s of seconds), the signals due to both the X-rays and reprocessed photons are pulsed. The shape of the spectrum of pulse amplitude as a function of wavelength yields information about both the temperature and size of the pulse-emitting region. It has been noted by several investigators that the optical pulsation amplitudes rise steeply toward short wavelengths. It is therefore a fair surmise that pulsation amplitudes peak in the ultraviolet. The scientific goal of this project was to observe a representative sample of IP's, using IUE, in search of the expected strong UV pulsations, and hence to further our understanding of pulse-producing mechanisms.

Koratkar, Anuradha; Bond, Howard E.

1995-01-01

209

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

210

The blueshifted Pa alpha broad line component and the origin of strong iron emission in the ultraluminous infrared galaxy IRAS 07598+6508  

NASA Technical Reports Server (NTRS)

We present the Pa alpha emission profile of the ultraluminous infrared galaxy (ULFIRG) IRAS 07598+6508 which is an unusually strong Fe II emitter in the optical. The Pa alpha emission line profile shows a blueshifted broad component (FWHM approximately equal to 3900 km/sec) together with a narrow core (FWHM less than or equal to 530 km/sec). The presence of the broad line component strongly suggests that IRAS 07598+6508 has an active galactic nucleus, supporting a scenario of merger-induced quasar formation proposed by Sanders et al. (1988), although we cannot rule out the possibility of a supernova-driven high speed wind. Possible detection of (Fe II) 1.893 micrometer emission is also reported. It is shown that strong Fe II emitters such as IRAS 07598+6508 have intermediate IRAS color properties between normal quasars and cold ultraluminous infrared galaxies. We thus suggest an evolutionary link from cold ULFIRG through warm ULFIRG and Fe II ULFIRG to quasars.

Taniguchi, Yoshiaki; Kawara, Kimiaki; Murayama, Takashi; Sato, Yasunori

1994-01-01

211

Predicted gamma-ray line emission from the Cygnus complex  

NASA Astrophysics Data System (ADS)

Context. The Cygnus region harbours a huge complex of massive stars at a distance of 1.0-2.0 kpc from us. About 170 O stars are distributed over several OB associations, among which the Cyg OB2 cluster is by far the most important with about 100-120 O stars. These massive stars inject large quantities of radioactive nuclei into the interstellar medium, such as 26Al and 60Fe, and their gamma-ray line decay signals can provide insight into the physics of massive stars and core-collapse supernovae. Aims: Past studies of the nucleosynthesis activity of Cygnus have concluded that the level of 26Al decay emission as deduced from CGRO/COMPTEL observations was a factor 2-3 above the predictions based on the theoretical yields available at that time and on the observed stellar content of the Cygnus region. We reevaluate the situation from new measurements of the gamma-ray decay fluxes with INTEGRAL/SPI (presented in a previous paper) and new predictions based on recently improved stellar models. Methods: We built a grid of nucleosynthesis yields from recent models of massive stars. Compared to previous works, our data include some of the effects of stellar rotation for the higher mass stars and a coherent estimate of the contribution from SNIb/c. We then developed a population synthesis code to predict the nucleosynthesis activity and corresponding decay fluxes of a given stellar population of massive stars. Results: The observed decay fluxes from the Cygnus complex are found to be consistent with the values predicted by population synthesis at solar metallicity; and yet, when extrapolated to the possible subsolar metallicity of the Cygnus complex, our predictions fail to account for the INTEGRAL/SPI measurements. The observed extent of the 1809 keV emission from Cygnus is found to be consistent with the result of a numerical simulation of the diffusion of 26Al inside the superbubble blown by Cyg OB2. Conclusions: Our work indicates that the past dilemma regarding the gamma-ray line emission from Cygnus resulted from an overestimate of the 1809 keV flux of the Cygnus complex, combined with an underestimate of the nucleosynthesis yields. Our results illustrate the importance of stellar rotation and SNIb/c in the nucleosynthesis of 26Al and 60Fe. The effects of binarity and metallicity may also be necessary to account for the observations satisfactorily.

Martin, P.; Knödlseder, J.; Meynet, G.; Diehl, R.

2010-02-01

212

The Broad-Complex gene is a tissue-specific modulator of the ecdysone response of the Drosophila hsp23 gene.  

PubMed Central

The steroid hormone ecdysone causes dramatic changes in the genetic programs leading to the pupariation of Drosophila melanogaster, and the Broad-Complex (BR-C) gene is known to play a key role in this process. Previously we showed that BR-C regulates developmental changes in transcription and chromatin structure of the 67B heat shock gene cluster, which contains four small hsp genes. Importantly, the downregulation of the hsp23 gene in the BR-C mutants correlates with the absence of a DNase I-hypersensitive site (DHS) at position -1400. To study the functional importance of the DHS-1400, we have introduced genomic fragments containing a modified hsp23 gene into the Drosophila germ line. Our analysis shows that the ecdysone response element is necessary but not sufficient for full developmental expression of hsp23 in the late third instar and that there is, indeed, another regulatory element, in the vicinity of DHS-1400. We also show that hsp23 developmental expression is not tissue specific. A construct lacking the ecdysone response element is unable to direct normal hsp23 expression in all tissues except the brain. Similarly, brain-specific expression is BR-C independent, although in the other tissues we find different requirements for BR-C genetic functions. The effect of the br mutations is restricted to wing imaginal discs and midgut tissue, while that of 2Bc is restricted to the fat body and Malpighian tubules, and mutations in the rbp group have no effect in any of the tissues studied. Thus, BR-C regulatory action is mediated through different genetic functions in a tissue-specific manner.

Dubrovsky, E B; Dretzen, G; Berger, E M

1996-01-01

213

The nature of the broad-line region in the radio-loud active galactic nucleus 3C 390.3  

NASA Astrophysics Data System (ADS)

We present the results of an analysis of the ultraviolet and X-ray variability of the broad-line radio (BLR) galaxy 3C 390.3 over 15 years. The ultraviolet (UV) continuum of 3C 390.3 shows large variations with amplitudes of up to a factor of 10. We find the following results. (1) The variations of Civ and Lyalpha are highly correlated with the UV continuum, and are delayed with respect to the continuum variations by 50-110d with the red wing of both Civ and Lyalpha leading the blue wing. (2) The Civ/Lyalpha ratio is positively correlated with both the continuum flux and UV line strength, a behaviour different from other AGNs studied so far. (3) The blue sides of the Lyalpha and Civ profiles are similar to the blue side of the Balmer lines, while the red sides are different, suggesting a different origin for the red peak in the Balmer lines. The X-ray spectra of 3C 390.3 observed with ROSAT can be well fitted by a single power law at Galactic absorption with a spectral slope of alpha=0.9. The overall optical, UV to X-ray spectrum can also be described by a single power law with alpha_uvx=0.89, indicating a very weak or no big blue bump. The unusual behaviour of Civ/Lyalpha variations might be related to this hard ionizing continuum in 3C 390.3. Our results suggest: (i) the broad Civ and Lyalpha emitting gas is infalling towards the central object in 3C 390.3; (ii) the overall behaviour of the Civ/Lyalpha ratio and the absence of a big blue bump strongly indicate the coexistence of optically thick as well as optically thin BLR clouds; (iii) assuming circular symmetry and predominantly circular motion, the BLR gas is situated at 83+/-25 light-days from the central source; (iv) under these assumptions and with the derived circular velocity of v_rot~=2850 km s^-1, the central mass inside this radius is confined to 1.3x10^8Msolar< M_CM<4.0x10^8 Msolar (v) comparing our results with those obtained from very long-baseline interferometry (VLBI) and observations of the FeKalpha line suggests the association of the BLR with a disc, inclined at 98 deg+/-12 deg with respect to the direction of superluminal motion of the radio blobs.

Wamsteker, Willem; Wang, Ting-Gui; Schartel, Norbert; Vio, Roberto

1997-06-01

214

Isolation and characterization of novel mutations of the Broad-Complex, a key regulatory gene of ecdysone induction in Drosophila melanogaster  

Microsoft Academic Search

Seven new alleles of the Broad-Complex gene of Drosophila melanogaster, which encodes a family of four zinc finger protein isoforms BR-C Z1, Z2, Z3 and Z4, were generated by transposase-induced mobilization of a P[Zw] element inserted in either the first intron downstream from the P165 promoter or the exon encoding the Z2-specific zinc finger domain. They were characterized by genetic

G Gonzy; G. V Pokholkova; F Peronnet; B Mugat; O. V Demakova; I. V Kotlikova; J.-A Lepesant; I. F Zhimulev

2002-01-01

215

THE DEMOGRAPHICS OF BROAD-LINE QUASARS IN THE MASS-LUMINOSITY PLANE. II. BLACK HOLE MASS AND EDDINGTON RATIO FUNCTIONS  

SciTech Connect

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 {approx}58, 000 quasars from the Sloan Digital Sky Survey (SDSS) DR7. We find that the SDSS becomes significantly incomplete at M {sub BH} {approx}< 3 Multiplication-Sign 10{sup 8} M {sub Sun} or L/L {sub Edd} {approx}< 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 {sub Edd} {approx} 3. Consistent with our results in Shen and 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. [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93107 (United States)] [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93107 (United States); Shen, Yue [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51, Cambridge, MA 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51, Cambridge, MA 02138 (United States)

2013-02-10

216

Hubble Space Telescope Observations of the Gravitationally Lensed Cloverleaf Broad Absorption Line QSO H1413+1143: Imaging Polarimetry and Evidence for Microlensing of a Scattering Region  

NASA Astrophysics Data System (ADS)

We report the results of Hubble Space Telescope Wide Field and Planetary Camera 2 broadband F555W and F702W photometric and F555W polarimetric observations of the ``Cloverleaf'' QSO H1413+1143. This is a four-component gravitationally-lensed broad absorption line (BAL) QSO. Observations were obtained at two epochs in 1999 March and 1999 June separated by ~100 days. The observations were photometrically and polarimetrically calibrated using the standard ``pipeline'' calibration procedures implemented at the Space Telescope Science Institute. The goal of our program was to detect any relative changes among the components and between the two epochs. Over this time baseline we detected an ~0.07 mag dimming in component D of the lensed image, which we interpret as evidence for microlensing. In 1999 March we find significant evidence for a difference in the relative linear polarization of component D in comparison to the other three components; in 1999 June the combined polarization of the Cloverleaf components was lower. In 1999 March the apparently microlensed component D has a rotated polarization position angle and a somewhat higher degree of polarization than the other three components. We suggest that this difference in polarization is due to microlensing magnification of part of a scatter-light (i.e., polarized) continuum-producing region. The results indicate that in the Cloverleaf the size scale of the polarized scattered-light region exceeds ~1016 cm but lies interior to the region producing the broad emission lines (<1018 cm). Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Space Telescope Science Institute, which is operated under NASA contract NAS 5-26555.

Chae, Kyu-Hyun; Turnshek, David A.; Schulte-Ladbeck, Regina E.; Rao, Sandhya M.; Lupie, Olivia L.

2001-11-01

217

THE DEMOGRAPHICS OF BROAD-LINE QUASARS IN THE MASS-LUMINOSITY PLANE. I. TESTING FWHM-BASED VIRIAL BLACK HOLE MASSES  

SciTech Connect

We jointly constrain the luminosity function (LF) and black hole mass function (BHMF) of broad-line quasars with forward Bayesian modeling in the quasar mass-luminosity plane, based on a homogeneous sample of {approx}58, 000 Sloan Digital Sky Survey (SDSS) Data Release 7 quasars at z {approx} 0.3-5. We take into account the selection effect of the sample flux limit; more importantly, we deal with the statistical scatter between true BH masses and FWHM-based single-epoch virial mass estimates, as well as potential luminosity-dependent biases of these mass estimates. The LF is tightly constrained in the regime sampled by SDSS and makes reasonable predictions when extrapolated to {approx}3 mag fainter. Downsizing is seen in the model LF. On the other hand, we find it difficult to constrain the BHMF to within a factor of a few at z {approx}> 0.7 (with Mg II and C IV-based virial BH masses). This is mainly driven by the unknown luminosity-dependent bias of these mass estimators and its degeneracy with other model parameters, and secondly driven by the fact that SDSS quasars only sample the tip of the active BH population at high redshift. Nevertheless, the most likely models favor a positive luminosity-dependent bias for Mg II and possibly for C IV, such that at fixed true BH mass, objects with higher-than-average luminosities have overestimated FWHM-based virial masses. There is tentative evidence that downsizing also manifests itself in the active BHMF, and the BH mass density in broad-line quasars contributes an insignificant amount to the total BH mass density at all times. Within our model uncertainties, we do not find a strong BH mass dependence of the mean Eddington ratio, but there is evidence that the mean Eddington ratio (at fixed BH mass) increases with redshift.

Shen Yue; Kelly, Brandon C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2012-02-20

218

Complex variability pattern in NGC 4151. I. Sequences on the line-continuum diagram.  

NASA Astrophysics Data System (ADS)

We present the first results of an 8-year spectroscopic monitoring of the Seyfert 1.5 galaxy NGC 4151 carried out with a CCD spectrograph at the 2.6-m Shajn Telescope of the Crimean Astrophysical Observatory in 1988-1995. Total of 202 H? region spectra and 154 H? region spectra have formed the data set. All spectra were calibrated in flux using the narrow emission lines which were assumed to be constant over the duration of the monitoring program. A self-consistent seeing correction procedure not requiring the surface brightness distribution of the narrow-line region to be known is proposed. The seeing-corrected H?, H?, and HeII ?4686 integrated line fluxes and the optical continuum fluxes at 4480Å, 5120Å, 6230Å, and 6910Å are tabulated. During the monitoring program, the spectrum and luminosity of NGC 4151 have undergone dramatic changes. The broad-line fluxes grew by at least 4.6 times for the H?, 6.5 times for the H?, and 9 times for the HeII ?4686 lines whereas the non-thermal optical continuum at 5120Å increased by at least 4.8 times. The light curve of the HeII ?4686 line strongly differs from the H? and H? light curves. Moreover, there is a clearly pronounced, broad, variable emission near the observed wavelength 4540Å whose variations are not correlated with variations of the broad HeII ?4686 line. The line-continuum diagrams for NGC 4151 reveal some features which contradict the simplest AGN paradigm where a single central source of the continuum emission has a steady relationship between the visible and ionizing continuum: (1) each of the dependences of H?, H?, and HeII ?4686 emission-line fluxes on the optical continuum flux split into four sequences which cover different periods of observations and differ by most parameters of the line-continuum and line-line correlations, including the time lag between the continuum and line variations; (2) some sequences do not pass through the zero-point of both broad-line and non-thermal optical continuum fluxes, and the relative position of these sequences on the line-continuum diagram is quite different for the hydrogen and HeII lines; (3) the transition time between two successive sequences (~ 100 days or less) is much shorter than the dynamical time scale for the broad-line region (~ several years), so the spatial redistribution of the line-emitting gas is obviously not the cause of the origin of sequences (and, hence, of the changes in the emission-line lag).

Malkov, Yu. F.; Pronik, V. I.; Sergeev, S. G.

1997-08-01

219

Structure of a classical broadly neutralizing stem antibody in complex with a pandemic H2 influenza virus hemagglutinin.  

PubMed

We report the structural characterization of the first antibody identified to cross-neutralize multiple subtypes of influenza A viruses. The crystal structure of mouse antibody C179 bound to the pandemic 1957 H2N2 hemagglutinin (HA) reveals that it targets an epitope on the HA stem similar to those targeted by the recently identified human broadly neutralizing antibodies. C179 also inhibits the low-pH conformational change of the HA but uses a different angle of approach and both heavy and light chains. PMID:23552413

Dreyfus, Cyrille; Ekiert, Damian C; Wilson, Ian A

2013-06-01

220

Ultra-precision turning of complex spiral optical delay line  

NASA Astrophysics Data System (ADS)

Optical delay line (ODL) implements the vertical or depth scanning of optical coherence tomography, which is the most important factor affecting the scanning resolution and speed. The spinning spiral mirror is found as an excellent optical delay device because of the high-speed and high-repetition-rate. However, it is one difficult task to machine the mirror due to the special shape and precision requirement. In this paper, the spiral mirror with titled parabolic generatrix is proposed, and the ultra-precision turning method is studied for its machining using the spiral mathematic model. Another type of ODL with the segmental shape is also introduced and machined to make rotation balance for the mass equalization when scanning. The efficiency improvement is considered in details, including the rough cutting with the 5- axis milling machine, the machining coordinates unification, and the selection of layer direction in turning. The onmachine measuring method based on stylus gauge is designed to analyze the shape deviation. The air bearing is used as the measuring staff and the laser interferometer sensor as the position sensor, whose repeatability accuracy is proved up to 10nm and the stable feature keeps well. With this method developed, the complex mirror with nanometric finish of 10.7nm in Ra and the form error within 1um are achieved.

Zhang, Xiaodong; Li, Po; Fang, Fengzhou; Wang, Qichang

2011-11-01

221

Eye-hand strategies in copying complex lines.  

PubMed

Eye movements and eye-hand interactions have been recorded for 10 beginner art students copying complex lines representing outlines of caricature heads seen in profile. Four copying conditions mimicking real-world drawing situations were tested: Direct copying where the original and copy were placed side by side, Direct Blind copying where the subject could not see the drawing hand and copy, Memory copying where the original was first memorized for drawing and subsequently hidden before drawing commenced, and Non-specific Memory copying where the original was encoded for facial recognition before being hidden and drawn from memory. We observed four very different eye-hand interaction strategies which provide evidence for the eye's dual role in the copying process: acquiring visual information in order to activate the visuomotor transformation and guiding the hand on the paper. The Direct copying strategies were best understood in terms of a Drawing Hypothesis stating that shape is the result of visuomotor mapping alone and, consequently, can be accurately drawn without vision of the drawing hand or paper. A double just-in-time mechanism is proposed whereby the eye refers alternatively to the original for shape and to the copy for spatial position just in time for the drawing action to proceed continuously. PMID:18656183

Tchalenko, John; Chris Miall, R

2009-03-01

222

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

223

Identification of Vulnerable Lines in Power Grid Based on Complex Network Theory  

Microsoft Academic Search

Some critical lines can have important impact on the large-scale blackouts and cascading failures in power grid. Based on the newest progress in the field of complex network, a new vulnerability index called weighted line betweenness is proposed as vulnerability index in this paper. The weighted line betweenness of one line is defined as the sum of the loads acted

Xiaogang Chen; Ke Sun; Yijia Cao; Shaobu Wang

2007-01-01

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  

NASA Astrophysics Data System (ADS)

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 emission lines to respond to continuum variations with time delays of about 2.3d-3.1d for Ly?, 2.7d for C IV ?1549, 1.9d-2.4d for N V ?1240, 1.7d-1.8d for Si IV ?1400, and 0.7d-1.0d for He II ?1640. The most remarkable result, however, is the detection of apparent time delays between the different UV continuum bands. With respect to the UV continuum flux at 1315 Å, the flux at 1485 Å, 1740 Å, and 1825 Å lags with time delays of 0.21d, 0.35d, and 0.28d, respectively. Determination of the significance of this detection is somewhat problematic since it depends on accurate estimation of the uncertainties in the lag measurements, which are difficult to assess. We attempt to estimate the uncertainties in the time delays through Monte Carlo simulations, and these yield estimates of ~0.07d for the 1 ? uncertainties in the interband continuum time delays. Possible explanations for the delays include the existence of a continuum-flux reprocessing region close to the central source and/or a contamination of the continuum flux with a very broad time-delayed emission feature such as the Balmer continuum or merged Fe II multiplets.

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

1997-11-01

225

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

226

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

227

Mutation in Integrin-Linked Kinase (ILKR211A) and Heat-Shock Protein 70 Comprise a Broadly Cardioprotective Complex  

PubMed Central

Rationale Integrin-linked kinase (ILK) has been proposed as a novel molecular target that has translational potential in diverse cardiac diseases, since its upregulation promotes a broadly cardioprotective phenotype. However, ILK has been implicated as both a cardioprotective and oncogenic target, which imposes therapeutic constraints that are generally relevant to the translational potential of many kinases. Objective To study the cardioprotective properties of the activation-resistant, non-oncogenic, mutation of ILK (ILKR211A) against experimental MI in vivo and Doxorubicin induced apoptosis in vitro and it’s relationships to stress induced heat shock proteins. Methods/Results The transgenic mouse heart over-expressing a point mutation in the ILK pleckstrin homology (PH) domain (TgR211A) exhibits a highly cardioprotective phenotype based on LAD-ligation-induced MI reduction in vivo, and on protection against doxorubicin (DOX)-induced cardiomyocyte apoptosis when overexpressed in human induced pluripotent stem cell (iPS)-derived cardiomyocytes in vitro. Intriguingly, the degree of cardioprotection seen with the ILKR211A mutation exceeded that with the ILKS343D mutation. Microarray and immunoprecipitation analyses revealed upregulation of expression levels and specific binding of ILKWT, ILKS343D and ILKR211A to both constitutively active heat-shock protein 70 (Hsc70) and inducible Hsp70 in response to MI, and to acute ILK overexpression in iPSC-cardiomyocytes. ILK-mediated cardioprotection was shown to depend upon Hsp70 ATPase activity. Conclusions These findings indicate that wild type ILK and the non-oncogenic ILKR211A mutation comprise a cardioprotective module with Hsp/c70. These results advance a novel target discovery theme in which kinase mutations can be safely engineered to enhance cardioprotective effects.

Traister, Alexandra; Walsh, Mark; Aafaqi, Shabana; Lu, Mingliang; Dai, Xiaojing; Henkleman, Mark R.; Momen, Abdul; Zhou, Yu-Quing; Husain, Mansoor; Arab, Sara; Piran, Sara; Hannigan, Gregory; Coles, John G.

2013-01-01

228

TESTING THE EVOLUTIONARY SEQUENCE BETWEEN HIDDEN BROAD-LINE REGION (HBLR) AND NON-HBLR SEYFERT 2 GALAXIES WITH THE 4000 A BREAK STRENGTHS  

SciTech Connect

We compare the 4000 A break (D{sub n} (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 D{sub n} (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 D{sub n} (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; Hwang, Chorng-Yuan [Graduate Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Huang, Kui-Yun; Ohyama, Youichi, E-mail: pcyu@astro.ncu.edu.tw, E-mail: hwangcy@astro.ncu.edu.tw, E-mail: ljhuang@asiaa.sinica.edu.tw, E-mail: ohyama@asiaa.sinica.edu.tw [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China)

2013-05-01

229

Optical follow-up observations of PTF10qts, a luminous broad-lined Type Ic supernova found by the Palomar Transient Factory  

NASA Astrophysics Data System (ADS)

We present optical photometry and spectroscopy of the broad-lined Type Ic supernova (SN Ic-BL) PTF10qts, which was discovered as part of the Palomar Transient Factory. The SN was located in a dwarf galaxy of magnitude r = 21.1 at a redshift z = 0.0907. We find that the R-band light curve is a poor proxy for bolometric data and use photometric and spectroscopic data to construct and constrain the bolometric light curve. The derived bolometric magnitude at maximum light is Mbol = -18.51 ± 0.2 mag, comparable to that of SN 1998bw (Mbol = -18.7 mag) which was associated with a gamma-ray burst (GRB). PTF10qts is one of the most luminous SNe Ic-BL observed without an accompanying GRB. We estimate the physical parameters of the explosion using data from our programme of follow-up observations, finding that it produced a larger mass of radioactive nickel compared to other SNe Ic-BL with similar inferred ejecta masses and kinetic energies. The progenitor of the event was likely an ˜20 M? star.

Walker, E. S.; Mazzali, P. A.; Pian, E.; Hurley, K.; Arcavi, I.; Cenko, S. B.; Gal-Yam, A.; Horesh, A.; Kasliwal, M.; Poznanski, D.; Silverman, J. M.; Sullivan, M.; Bloom, J. S.; Filippenko, A. V.; Kulkarni, S. R.; Nugent, P. E.; Ofek, E.; Barthelmy, S.; Boynton, W.; Goldsten, J.; Golenetskii, S.; Ohno, M.; Tashiro, M. S.; Yamaoka, K.; Zhang, X. L.-.

2014-08-01

230

The very energetic, broad-lined Type Ic supernova 2010ah (PTF10bzf) in the context of GRB/SNe  

NASA Astrophysics Data System (ADS)

SN 2010ah, a very broad-lined Type Ic supernova (SN) discovered by the Palomar Transient Factory, was interesting because of its relatively high luminosity and the high velocity of the absorption lines, which was comparable to that of gamma-ray burst (GRB)/SNe, suggesting a high explosion kinetic energy. However, no GRB was detected in association with the SN. Here, the properties of SN 2010ah are determined with higher accuracy than previous studies through modelling. New Subaru telescope photometry is presented. A bolometric light curve is constructed taking advantage of the spectral similarity with SN 1998bw. Radiation transport tools are used to reproduce the spectra and the light curve. The results thus obtained regarding ejecta mass, composition and kinetic energy are then used to compute a synthetic light curve. This is in reasonable agreement with the early bolometric light curve of SN 2010ah, but a high abundance of 56Ni at high velocity is required to reproduce the early rise, while a dense inner core must be used to reproduce the slow decline at late phases. The high-velocity 56Ni cannot have been located on our line of sight, which may be indirect evidence for an off-axis, aspherical explosion. The main properties of SN 2010ah are: ejected mass Mej ? 3 M?; kinetic energy Ekin ? 1052 erg, M(56Ni) ? 0.25 M?. The mass located at v ? 0.1 c is ˜0.2 M?. Although these values, in particular the Ekin, are quite large for a Type Ic SN, they are all smaller (especially Mej) than those typical of GRB/SNe. This confirms the tendency for these quantities to correlate, and suggests that there are minimum requirements for a GRB/SN, which SN 2010ah may not meet although it comes quite close. Depending on whether a neutron star or a black hole was formed following core collapse, SN 2010ah was the explosion of a CO core of ˜5 to 6 M?, pointing to a progenitor mass of ˜24-28 M?.

Mazzali, Paolo A.; Walker, Emma S.; Pian, Elena; Tanaka, Masaomi; Corsi, Alessandra; Hattori, Takashi; Gal-Yam, Avishay

2013-07-01

231

An on-line HPLC method for detection of radical scavenging compounds in complex mixtures.  

PubMed

A rapid on-line method for screening of complex mixtures for radical scavenging components was developed using a methanolic solution of 2,2'-diphenyl-1-picrylhydrazyl (DPPH) stable free radical. The HPLC-separated analytes react postcolumn with the DPPH solution, and the induced bleaching is detected as a negative peak by an absorbance detector at 517 nm. An optimized instrumental setup is presented. The method is suitable for both isocratic and gradient HPLC runs with mobile-phase compositions ranging from 10 to 90% organic solvent in water or buffer (pH 3-6). The method is simple, has a broad applicability, and uses common instruments, inexpensive and stable reagents, and a time-saving and nonlaborious experimental protocol. It can also be used for quantitative analysis. The method was applied to several pure natural antioxidants and plant extracts. The limits of detection were 0.33-94 microg/mL, depending on the compound tested. PMID:10845381

Koleva, I I; Niederländer, H A; van Been, T A

2000-05-15

232

The broad-spectrum metalloproteinase inhibitor BB-94 inhibits growth, HER3 and Erk activation in fulvestrant-resistant breast cancer cell lines.  

PubMed

Breast cancer cells can switch from estrogen receptor ? (ER)- to human epidermal growth factor receptor (HER)-driven cell growth upon acquiring antiestrogen resistance. HER ligands are cleaved by metalloproteinases leading to release of active HER ligands, activation of HER receptors and consequently increased cell growth. In this study, we investigated the importance of HER receptors, in particular HER3, and HER ligand shedding for growth and signaling in human MCF-7 breast cancer cells and MCF-7-derived sublines resistant to the antiestrogen fulvestrant. The HER3/HER4 ligand heregulin 1? induced phosphorylation of HER3, Akt and Erk, and partly rescued fulvestrant-inhibited growth of MCF-7 cells. HER3 ligands were found to be produced and shed from the fulvestrant-resistant cells as conditioned medium from fulvestrant-resistant MCF-7 cells induced phosphorylation of HER3 and Akt in MCF-7 cells. This was prevented by treatment of resistant cells with the metalloproteinase inhibitor TAPI-2. Only the broad-spectrum metalloproteinase inhibitor BB-94, and not the more selective inhibitors GM6001 or TAPI-2, which inhibited shedding of the HER ligands produced by the fulvestrant-resistant cells, was able to inhibit growth and activation of HER3 and Erk in resistant cells. Compared to MCF-7, fulvestrant-resistant cells have increased HER3 phosphorylation, but knockdown of HER3 had no inhibitory effect on resistant cell growth. The EGFR inhibitor gefitinib exhibited only a minor growth inhibition, whereas the pan-HER inhibitor CI-1033 exerted growth arrest. Thus, neither HER3 nor EGFR alone are the main driver of fulvestrant-resistant cell growth and treatment should target both receptors. Ligand shedding is not a treatment target, as receptor activation occurred, independent of release of ligands. Only the broad-spectrum metalloproteinase inhibitor BB-94 could abrogate HER3 and Erk activation in the resistant cells, which stresses the complexity of the resistance mechanisms and the requirement of targeting signaling from HER receptors by multiple strategies. PMID:24819550

Kirkegaard, Tove; Yde, Christina W; Kveiborg, Marie; Lykkesfeldt, Anne E

2014-07-01

233

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

234

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

235

Weak Hard X-ray Emission from Broad Absorption Line Quasars Observed with NuSTAR: Evidence for Intrinsic X-ray Weakness  

NASA Astrophysics Data System (ADS)

We report NuSTAR observations of a sample of six X-ray weak broad absorption line (BAL) quasars. These targets, at z=0.148-1.223, are among the optically brightest and most luminous BAL quasars known at z<1.3. However, their rest-frame 2 keV luminosities are 14 to >330 times weaker than expected for typical quasars. Our results from a pilot NuSTAR study of two low-redshift BAL quasars, a Chandra stacking analysis of a sample of high-redshift BAL quasars, and a NuSTAR spectral analysis of the local BAL quasar Mrk 231 have already suggested the existence of intrinsically X-ray weak BAL quasars, i.e., quasars not emitting X-rays at the level expected from their optical/UV emission. The aim of the current program is to extend the search for such extraordinary objects. Three of the six new targets are weakly detected by NuSTAR with <45 counts in the 3-24 keV band, and the other three are not detected. The hard X-ray (8-24 keV) weakness observed by NuSTAR requires Compton-thick absorption if these objects have nominal underlying X-ray emission. However, a soft stacked effective photon index (Γ 1.8) for this sample disfavors Compton-thick absorption in general. The uniform hard X-ray weakness observed by NuSTAR for this and the pilot samples selected with <10 keV weakness also suggests that the X-ray weakness is intrinsic in at least some of the targets. We conclude that the NuSTAR observations have likely discovered a significant population (>33%) of intrinsically X-ray weak objects among the BAL quasars with significantly weak <10 keV emission. We suggest that intrinsically X-ray weak quasars might be preferentially observed as BAL quasars.

Luo, Bin; Brandt, W. Niel; Alexander, David M; Stern, Daniel; Teng, Stacy H.; Arevalo, Patricia; Bauer, Franz E.; Boggs, Steven E.; Christensen, Finn; Comastri, Andrea; Craig, William W.; Farrah, Duncan; Gandhi, Poshak; Hailey, Charles James; Harrison, Fiona; Koss, Michael; Ogle, Patrick M.; Puccetti, Simonetta; Saez, Cristian; Scott, Amy; Walton, Dom; Zhang, William

2014-08-01

236

WEAK HARD X-RAY EMISSION FROM TWO BROAD ABSORPTION LINE QUASARS OBSERVED WITH NuSTAR: COMPTON-THICK ABSORPTION OR INTRINSIC X-RAY WEAKNESS?  

SciTech Connect

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 Almost-Equal-To 400-600 hard X-ray ({approx}> 10 keV) photons with NuSTAR, provided that these photons are not significantly absorbed (N{sub H} {approx}< 10{sup 24} cm{sup -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{sub H} Almost-Equal-To 7 Multiplication-Sign 10{sup 24} cm{sup -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{alpha} 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. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); Alexander, D. M.; Hickox, R. [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Harrison, F. A.; Fuerst, F.; Grefenstette, B. W.; Madsen, K. K. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Stern, D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Bauer, F. E. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile); Boggs, S. E.; Craig, W. W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, F. E. [DTU Space-National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Comastri, A. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Fabian, A. C. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Farrah, D. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Fiore, F. [Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio Catone (Italy); Hailey, C. J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Matt, G. [Dipartimento di Matematica e Fisica, Universita degli Studi Roma Tre, via della Vasca Navale 84, I-00146 Roma (Italy); Ogle, P. [IPAC, California Institute of Technology, Mail Code 220-6, Pasadena, CA 91125 (United States); and others

2013-08-01

237

Approximating Complex Surfaces by Triangulation of Contour Lines  

Microsoft Academic Search

An algorithm is described for obtaining an optimal approximation, using triangulation, of a three-dimensiona l surface de- fined by randomly distributed points along contour lines. The combinatorial problem of finding the best arrangement of triangles is treated by assuming an adequate objective function. The optimal triangulation is found using classical methods of graph theory. An il- lustrative example

Eric Keppel

1975-01-01

238

The Properties of X-Ray--selected Active Galactic Nuclei. IV. The Local Optical Luminosity Function of Broad-Line Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

We have selected a local (z <= 0.3) subsample of 226 broad line active galactic nuclei (BLAGNs) from the Einstein Observatory Extended Medium Sensitivity Survey. This sample represents the largest unbiased and complete sample of local BLAGNs ever assembled and has allowed us to derive their space density in regions of the m_B_ - z plane where, with the usual optical selection criteria, it is very difficult to obtain complete samples of BLAGNs. Using total integrated magnitudes (i.e., nucleus + host galaxy), we have computed the local optical luminosity function of this X-ray selected sample and compared it with those derived from local optical samples. Thanks to the large number of objects at our disposal we can set more stringent constraints on the space density of BLAGNs than has previously been possible. The luminosity function derived from our sample is in good agreement with the composite luminosity function which can be derived from optically selected samples only by using different selection criteria in different ranges of absolute magnitude. In particular, at low luminosity (M_B_ >= - 22) we confirm the flattening of the local optical luminosity function originally suggested by Meurs & Wilson (1984) while in the magnitude range from M_B_ ~ -23 to -25 we find a very good agreement with the optical spatial density derived using data from the Bright Quasars Survey. By convolving our luminosity function with the distribution of the ratio of nuclear to total flux of a sample of ~40 Seyfert 1 and 1.5 galaxies from the literature, we have also derived an estimate for the nuclear luminosity function of BLAGNs: This nuclear luminosity function is in rather good agreement with the nuclear luminosity functions previously derived, using a much smaller number of objects, from optical samples of low-luminosity BLAGNs. A reasonably good agreement is also found between our luminosity function and the extrapolation to low redshift (z = 0.15, the average redshift of our sample) of the quasar luminosity function derived from more than 1000 optically selected quasars. The integration of our nuclear luminosity function over the M_B_ - z plane shows that good agreement is obtained with the observed number counts of low luminosity (M_B_ >= - 23) BLAGNs at faint magnitudes, if the M_B_ >= -23 population evolves similarly to the QSO population.

della Ceca, Roberto; Zamorani, Giovanni; Maccacaro, Tommaso; Setti, Giancarlo; Wolter, Anna

1996-07-01

239

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

240

Identifying vulnerable lines in a power network using complex network theory  

Microsoft Academic Search

The latest developments in complex network theory have provided a new direction to power system research. Based on this theory a power system can be modelled as a graph with nodes and vertices and further analysis can help in identifying the important lines. This paper proposes a new betweenness index using the reactance of the transmission lines as the weight

Ajendra Dwivedi; Xinghuo Yu; Peter Sokolowski

2009-01-01

241

Biologicaly inspired on-line generation of complex movements using primitives  

Microsoft Academic Search

The objective of this work is to demonstrate the possibility of using primitives for on-line generation of complex movements that ensure motion of bipedal humanoid robots in unstructured environment where on-line generation of motion is required. Primitives represent simple movements that are either reflex or learned. Each primitive has its parameters and constraints that are determined on the basis of

Branislav Borovac; Mirko Rakovic; Milutin Nikolic

2011-01-01

242

Zooming into the broad line region of the gravitationally lensed quasar QSO 2237 + 0305 ? the Einstein Cross. III. Determination of the size and structure of the C iv and C iii] emitting regions using microlensing  

NASA Astrophysics Data System (ADS)

Aims: We aim to use microlensing taking place in the lensed quasar QSO 2237 + 0305 to study the structure of the broad line region (BLR) and measure the size of the region emitting the C iv and C iii] lines. Methods: Based on 39 spectrophotometric monitoring data points obtained between Oct. 2004 and Dec. 2007, we derived lightcurves for the C iv and C iii] emission lines. We used three different techniques to analyse the microlensing signal. Different components of the lines (narrow, broad, and very broad) were identified and studied. We built a library of the simulated microlensing lightcurves that reproduce the signal observed in the continuum and in the lines provided only the source size is changed. A Bayesian analysis scheme is then developed to derive the size of the various components of the BLR. Results: 1. The half-light radius of the region emitting the C iv line is found to be RC IV} ˜ 66+110-46} light-days = 0.06+0.09-0.04 pc = 1.7+2.8-1.1 × 1017 cm (at 68.3% CI). Similar values are obtained for C iii]. Relative sizes of the carbon-line and V-band continuum emitting-regions are also derived with median values of Rline/Rcont in the range 4 to 29, depending on the FWHM of the line component. 2. The size of the C iv emitting region agrees with the radius-luminosity relationship derived from reverberation mapping. Using the virial theorem, we derive the mass of the black hole in QSO 2237 + 0305 to be MBH ~ 108.3 ± 0.3 M?. 3. We find that the C iv and C iii] lines are produced in at least 2 spatially distinct regions, the most compact one giving rise to the broadest component of the line. The broad and narrow line profiles are slightly different for C iv and C iii]. 4. Our analysis suggests a different structure for the C iv and Fe ii+iii emitting regions, with the latter produced in the inner part of the BLR or in a less extended emitting region than C iv. Based on observations made with the ESO-VLT Unit Telescope # 2 Kueyen (Cerro Paranal, Chile; Proposals 073.B-0243(A&B), 074.B-0270(A), 075.B-0350(A), 076.B-0197(A), 177.B-0615(A&B), PI: F. Courbin).

Sluse, D.; Schmidt, R.; Courbin, F.; Hutsemékers, D.; Meylan, G.; Eigenbrod, A.; Anguita, T.; Agol, E.; Wambsganss, J.

2011-04-01

243

Wavelet-transform-based QRS complex detection in on-line Holter systems  

Microsoft Academic Search

Presents a QRS complex detection algorithm that can be applied in on-line Holter systems. The algorithm is performed in two steps: first the wavelet transform is applied to filter the signal, then QRS complex localization is accomplished using a maximum detection algorithm. The algorithm has been tested in two phases. First the QRS detection in ECG registrations from the MIT-BIH

L. Szilagyi

1999-01-01

244

Quick QRS Complex Detection for On-Line ECG and Holter Systems  

Microsoft Academic Search

This paper presents a new QRS complex detection algorithm that can be applied in various on-line ECG processing systems. The algorithm is performed in two steps: first a wavelet transform filtering is applied to the signal, then QRS complex localization is performed using a maximum detection and peak classification algorithm. The algorithm has been tested in two phases. First the

László Szilágyi; Sándor M. Szilágyi; Attila Frigy; Sándor E. László; Levente K. Görög; Zoltán Benyó

2005-01-01

245

Fast Analytical Computation of Power-Line Magnetic Fields by Complex Vector Method  

Microsoft Academic Search

The electromagnetic environment related to electric power installations is typically evaluated by numerical integration methods. Numerical techniques, although powerful, are not well suited for assessing the dependence of the field strength on electric and geometric parameters. In this paper, a fast procedure to analytically evaluate power-line magnetic fields, based on complex vectors, is proposed. The use of complex algebra greatly

Federico Moro; Roberto Turri

2008-01-01

246

Line-defects-mediated complex-oscillatory spiral waves in a chemical system  

NASA Astrophysics Data System (ADS)

In this paper, we summarize our experimental observations on complex-oscillatory spiral waves that arise in a Belousov-Zhabotinsky (BZ) reaction-diffusion system. The observed wave structures generically bear line defects across which the phase of local oscillation changes by a multiple of 2? . The local oscillation at every spatial point along a line defect of period-2 (P-2) oscillatory media is period-1 (P-1) oscillatory. For the homogeneous BZ reaction can be excitable, simply periodic, complex periodic, or chaotic as the control parameters are tuned, a number of different complex wave states are revealed. A two-dimensional phase diagram, which includes domains of P-2 oscillatory spirals, intermittently breathing spirals, period-3 (P-3) oscillatory spirals, two different types of mixed-mode periodic spirals, and line-defect-mediated turbulence, is constructed. Several different transitions among different dynamic states are described systematically. In all cases, line defects are found to play an important role.

Park, Jin-Sung; Lee, Kyoung J.

2006-06-01

247

Infrared mergers and infrared quasi-stellar objects with galactic winds - III. Mrk 231: an exploding young quasi-stellar object with composite outflow\\/broad absorption lines (and multiple expanding superbubbles)  

Microsoft Academic Search

We present a study of outflow (OF) and broad absorption line (BAL) systems in Mrk 231, and in similar infrared (IR) quasi-stellar objects (QSOs). This study is based mainly on one-dimensional and two-dimensional spectroscopy (obtained at La Palma\\/William Herschel Telescope, Hubble Space Telescope, International Ultraviolet Explorer, European Southern Observatory\\/New Technology Telescope, Kitt Peak National Observatory, Apache Point Observatory and Complejo

S. Lípari; R. Terlevich; W. Zheng; B. Garcia-Lorenzo; S. F. Sanchez; M. Bergmann

2005-01-01

248

Solution structures of the Bacillus cereus metallo-?-lactamase BcII and its complex with the broad spectrum inhibitor R-thiomandelic acid  

PubMed Central

Metallo-?-lactamases, enzymes which inactivate ?-lactam antibiotics, are of increasing biological and clinical significance as a source of antibiotic resistance in pathogenic bacteria. In the present study we describe the high-resolution solution NMR structures of the Bacillus cereus metallo-?-lactamase BcII and of its complex with R-thiomandelic acid, a broad-spectrum inhibitor of metallo-?-lactamases. This is the first reported solution structure of any metallo-?-lactamase. There are differences between the solution structure of the free enzyme and previously reported crystal structures in the loops flanking the active site, which are important for substrate and inhibitor binding and catalysis. The binding of R-thiomandelic acid and the roles of active-site residues are defined in detail. Changes in the enzyme structure upon inhibitor binding clarify the role of the mobile ?3–?4 loop. Comparisons with other metallo-?-lactamases highlight the roles of individual amino-acid residues in the active site and the ?3–?4 loop in inhibitor binding and provide information on the basis of structure–activity relationships among metallo-?-lactamase inhibitors.

Karsisiotis, Andreas Ioannis; Damblon, Christian F.; Roberts, Gordon C. K.

2013-01-01

249

Detection of CO (4-3), CO (9-8), and Dust Emission in the Broad Absorption Line Quasar APM 08279+5255 at a Redshift of 3.9  

NASA Astrophysics Data System (ADS)

With the IRAM interferometer, we detected the lines of CO (4-3) and CO (9-8) from the recently discovered broad absorption line quasar APM 08279+5255. The molecular lines are at a redshift of 3.911, which we take to be the true cosmological redshift of the quasar's host galaxy. This means that the quasar emission lines at z=3.87 are blueshifted by a kinematic component of -2500 km s-1 and, along with the broad absorption lines, are probably emitted in the quasar's wind or jet, moving toward us. The CO line ratios suggest that the molecular gas is at a temperature of ~200 K, at a density of ~4000 cm-3. We also detected the dust emission at 94 and 214 GHz (with emitted wavelengths of 650 and 290 ?m). The spectral index of the millimeter/submillimeter continuum is 3.2, indicating that the dust emission is optically thin in this part of the spectrum. The extremely high CO and dust luminosities suggest magnification by gravitational lensing. Using the optical extent and our limit on the size of the CO region, we estimate a magnification of 7-30 for the CO lines and the far-IR continuum and 14-60 for the optical/UV. In this interpretation, the molecular gas and dust are in a nuclear disk of radius 90-270 pc around the quasar. The quasar is 25-100 times stronger than, but otherwise resembles, the nucleus of Mrk 231.

Downes, D.; Neri, R.; Wiklind, T.; Wilner, D. J.; Shaver, P. A.

1999-03-01

250

Complex ridgelets for shift invariant characterization of surface topography with line singularities [rapid communication  

NASA Astrophysics Data System (ADS)

A complex ridgelet transform, which provides shift invariance and good performance for line singularities, is proposed to solve the problems with existing wavelet-based methods in surface metrology by taking a dual-tree complex wavelet transform on the projections of the finite Radon transform. Numerical experiments show the efficiency of this methodology in approximation, denoising, and characterization of engineering and bioengineering surfaces with straight scratches.

Ma, Jianwei; Jiang, Xiangqian; Scott, Paul

2005-09-01

251

Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei XVI: A 13 Year Study of Spectral Variability in NGC 5548  

NASA Technical Reports Server (NTRS)

We present the final installment of an intensive 13 year study of variations of the optical continuum and broad H beta emission line in the Seyfert 1 galaxy NGC 5548. The database consists of 1530 optical continuum measurements and 1248 H beta measurements. The H beta variations follow the continuum variations closely, with a typical time delay of about 20 days. However, a year-by-year analysis shows that the magnitude of emission-line time delay is correlated with the mean continuum flux. We argue that the data are consistent with the simple model prediction between the size of the broad-line region and the ionizing luminosity, r is proportional to L(sup 1/2)(sub ion). Moreover, the apparently linear nature of the correlation between the H beta response time and the nonstellar optical continuum F(sub opt) arises as a consequence of the changing shape of the continuum as it varies, specifically F(sub opt) is proportional to F(sup 0.56)(sub UV).

Peterson, B. M.; Berlind, P.; Bertram, R.; Bischoff, K.; Bochkarev, N. G.; Burenkov, A. N.; Calkins, M.; Carrasco, L.; Chavushyan, V. H.

2002-01-01

252

A Chandra HETGS Spectral Study of the Iron K Bandpass in MCG -6-30-15: A Narrow View of the Broad Iron Line  

Microsoft Academic Search

We present a high-resolution X-ray spectrum of the iron K bandpass in MCG -6-30-15 based on a 522 ks observation with Chandra's High Energy Transmission Grating Spectrometer (HETGS). The Chandra spectrum is consistent with the presence of a relativistically broadened, highly redshifted iron Kalpha emission line with a profile similar to previous observations. A number of narrow features are detected

A. J. Young; J. C. Lee; A. C. Fabian; C. S. Reynolds; R. R. Gibson; C. R. Canizares

2005-01-01

253

Testing of SNS-032 in a Panel of Human Neuroblastoma Cell Lines with Acquired Resistance to a Broad Range of Drugs12  

PubMed Central

Novel treatment options are needed for the successful therapy of patients with high-risk neuroblastoma. Here, we investigated the cyclin-dependent kinase (CDK) inhibitor SNS-032 in a panel of 109 neuroblastoma cell lines consisting of 19 parental cell lines and 90 sublines with acquired resistance to 14 different anticancer drugs. Seventy-three percent of the investigated neuroblastoma cell lines and all four investigated primary tumor samples displayed concentrations that reduce cell viability by 50% in the range of the therapeutic plasma levels reported for SNS-032 (<754 nM). Sixty-two percent of the cell lines and two of the primary samples displayed concentrations that reduce cell viability by 90% in this concentration range. SNS-032 also impaired the growth of the multidrug-resistant cisplatin-adapted UKF-NB-3 subline UKF-NB-3rCDDP1000 in mice. ABCB1 expression (but not ABCG2 expression) conferred resistance to SNS-032. The antineuroblastoma effects of SNS-032 did not depend on functional p53. The antineuroblastoma mechanism of SNS-032 included CDK7 and CDK9 inhibition-mediated suppression of RNA synthesis and subsequent depletion of antiapoptotic proteins with a fast turnover rate including X-linked inhibitor of apoptosis (XIAP), myeloid cell leukemia sequence 1 (Mcl-1), baculoviral IAP repeat containing 2 (BIRC2; cIAP-1), and survivin. In conclusion, CDK7 and CDK9 represent promising drug targets and SNS-032 represents a potential treatment option for neuroblastoma including therapy-refractory cases.

Loschmann, Nadine; Michaelis, Martin; Rothweiler, Florian; Zehner, Richard; Cinatl, Jaroslav; Voges, Yvonne; Sharifi, Mohsen; Riecken, Kristoffer; Meyer, Jochen; von Deimling, Andreas; Fichtner, Iduna; Ghafourian, Taravat; Westermann, Frank; Cinatl, Jindrich

2013-01-01

254

Keck HIRES Spectroscopy of the Fe II Low-Ionization Broad Absorption Line Quasar FBQS 0840+3633: Evidence for Two Outflows on Different Scales  

NASA Astrophysics Data System (ADS)

A Keck echelle spectrum of the quasar FBQS 0840+3633 reveals outflowing gas that gives rise to blueshifted absorption lines of many low-ionization species. The gas covers a range of velocities from -700 to -3500 km s-1, with two main components centered at -900 and -2800 km s-1. The physical conditions in the two main velocity components are found to be significantly different and can be attributed to a difference of a factor of ~100 in the distance from the central continuum source. The low-velocity gas shows absorption lines from excited states with relative strengths that indicate a low density. The level populations of low-lying Ni II, Si II, and Fe II states cannot be explained with a model based on collisional excitation and a single electron density. The lines of Si II provide an upper limit on the electron density of ne<500 cm-3, and another excitation mechanism must be responsible for the observed excitation of Fe II and Ni II. Assuming that this mechanism is UV fluorescence leads to an estimate of the distance between the low-velocity gas and the active nucleus of ~230 pc. Absorption lines from excited states formed in the high-velocity gas indicate a much higher density. This gas gives rise to Fe III and strong Al III absorption, which indicates that it contains the hydrogen ionization front on our line of sight to the active nucleus. The observed Fe III and Al III column densities and the absence of detectable absorption from the He I 23S state allow us to derive an estimate of the typical distance between the high-velocity gas and the active nucleus of ~1 pc. Based on observations obtained with the W. M. Keck Observatory, which is jointly operated by the California Institute of Technology and the University of California, and the Multiple Mirror Telescope Observatory, which is jointly operated by the University of Arizona and the Smithsonian Institution.

de Kool, Martijn; Becker, Robert H.; Arav, Nahum; Gregg, Michael D.; White, Richard L.

2002-05-01

255

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

256

A Chandra HETGS Spectral Study of the Iron K Bandpass in MCG6-30-15: A Narrow View of the Broad Iron Line  

Microsoft Academic Search

We present a high resolution X-ray spectrum of the iron K bandpass in\\u000aMCG-6-30-15 based on a 522 ksec observation with Chandra's High Energy\\u000aTransmission Grating Spectrometer. The Chandra spectrum is consistent with the\\u000apresence of a relativistically broadened, highly redshifted iron K alpha\\u000aemission line with a similar profile to previous observations. A number of\\u000anarrow features are detected

A. J. Young; J. C. Lee; A. C. Fabian; C. S. Reynolds; R. R. Gibson; C. R. Canizares

2005-01-01

257

Filling-In of Broad Far-Red Solar Lines by Terrestrial Fluorescence and Atmospheric Raman Scattering as Detected by SCIAMACHY Satellite Measurements  

NASA Technical Reports Server (NTRS)

Global mapping of terrestrial vegetation fluorescence from space has recently been accomplished with high spectral resolution measurements from the Japanese Greenhouse gases Observing SATellite (GOSAT). These data are of interest because they can potentially provide global information on the functional status of vegetation including light use efficiency and global primary productivity that can be used for global carbon cycle modeling. Quantifying the impact of fluorescence on the O2-A band is important as this band is used for cloud- and aerosol-characterization for other trace-gas retrievals including CO2. Here, we demonstrate that fluorescence information can be derived from space using potentially lower-cost hyperspectral instrumentation, i.e., more than an order of magnitude less spectral resolution than GOSAT, with a relatively simple algorithm. As a demonstration, we use the filling-in of one of the few wide and deep solar Fraunhofer lines in the red and far-red chlorophylla fluorescence bands, the calcium II line near 866 nm, to retrieve fluorescence with the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) satellite instrument. Although the signal from vegetation fluorescence is extremely weak at 866 nm, our results suggest that useful information may be obtained after adjustments are made to the observed spectra to correct for instrumental artifacts. We compare fluorescence from SCIAMACHY with that retrieved at 758 and 770 nm from similarly-corrected GOSAT data as well with the Enhanced Vegetation Index (EVI) from the MODerate-resolution Imaging Spectroradiometer (MODIS). We also show that filling-in occurs at 866 nm over barren areas, possibly originating from luminescent minerals in rock and soil.

Joiner, J.; Yoshida, Y.; Vasilkov, A. P.; Middleton, E. M.; Campbell, P. K. E.; Yoshida, Y.; Kuze, A.; Corp, L. A.

2011-01-01

258

Categories of holomorphic line bundles on higher dimensional noncommutative complex tori  

SciTech Connect

We construct explicitly noncommutative deformations of categories of holomorphic line bundles over higher dimensional tori. Our basic tools are Heisenberg modules over noncommutative tori and complex/holomorphic structures on them introduced by Schwarz ['Theta functions on noncommutative tori', Lett. Math. Phys. 58, 81-90 (2001)]. We obtain differential graded (DG) categories as full subcategories of curved DG categories of Heisenberg modules over the complex noncommutative tori. Also, we present the explicit composition formula of morphisms, which, in fact, depends on the noncommutativity.

Kajiura, Hiroshige [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)

2007-05-15

259

Cytotoxicity of gold(III) complexes on A549 human lung carcinoma epithelial cell line.  

PubMed

We have studied the kinetics of the complex formation of gold(III) complexes, [Au(en)Cl2]+ (dichlorido( ethylendiamine)aurate(III)-ion) [Au(dach)Cl2] (dichloride(1,2-diaminocyclohexane)aurate(III)-ion) and [Au(bipy)Cl2]+ (dichlorido(2,2'-bipyridyl)aurate(III)-ion) with guanosine5'-monophosphate (5'-GMP). It was shown that 5'-GMP have a high affinity for gold(III) complex, which may have important biological implications, since the interactions of Au(III) with DNA are thought to be responsible for the anti-tumor activity. The [Au(bipy)Cl2]+ complex is more reactive than [Au(en)Cl2]+ or [Au(dach)Cl2]+. The activation parameters for all studied reactions suggest an associative substitution mechanism. The cytotoxicity of gold(III) complexes was tested on A549 human lung carcinoma epithelial cell line and was evaluated by cytotoxic (MTT and LDH test) and apoptotic assays. The results showed that all tested gold(III) complexes displayed cytotoxic effect on A549 cells. Among the tested gold (III) complexes, AuBIPY showed the best cytotoxic effects. PMID:22420544

Arsenijevi?, Milos; Milovanovic, Marija; Volarevic, Vladislav; Djekovi?, Ana; Kanjevac, Tatjana; Arsenijevi?, Nebojsa; Duki?, Svetlana; Bugarci?, Zivadin D

2012-01-01

260

Characterization of a Chromosomally Complex Lung Cancer Cell Line Using Multiwell Fluorescence In Situ Hybridization  

Microsoft Academic Search

The chromosomal characterization of a non-small cell lung cancer cell line (NCIH358) is described. This characterization was achieved using a simple, cheap and technically straightforward multiwell fluorescence in situ hybridization (FISH) method. The many and complex chromosome rearrangements identified by this method could not be defined using conventional G-banded chromosome analysis, and have not been previously described. For the detailed

C. Mackie Ogilvie; S Shemilt; A. F Davies; S Weber-Hall; C.-Y Chuang; V Sundaresan

2000-01-01

261

The Broad Iron K-alpha line of Cygnus X-1 as Seen by XMM-Newton in the EPIC-pn Modified Timing Mode  

NASA Technical Reports Server (NTRS)

We present the analysis of the broadened, flourescent iron K(alpha) line in simultaneous XMM-Newton and RXTE data from the black hole Cygnus X-I. 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(alpha) band. We find that the best-fit spectrum consists of the sum of an exponentially cut-off power-law and relativistically smeared, ionized reflection. The shape of the broadened Fe K(alpha) feature is due to strong Compton broadening combined with relativistic broadening. Assuming a standard, thin accretion disk, the black hole is close to maximally rotating. Key words. X-rays: binaries - black hole physics - gravitation

Duro, Refiz; Dauser, Thomas; Wilms, Jorn; Pottschmidt, Katja; Nowak, Michael A.; Fritz, Sonja; Kendziorra, Eckhard; Kirsch, Marcus G. F.; Reynolds, Christopher S.; Staubert, Rudiger

2011-01-01

262

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

263

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

264

Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. 8: An intensive HST, IUE, and ground-based study of NGC 5548  

NASA Technical Reports Server (NTRS)

We present the data and initial results from a combined HST/IUE/ground-based spectroscopic monitoring campaign on the Seyfert 1 galaxy NGC 5548 that was undertaken in order to address questions that require both higher temporal resolution and higher signal-to-noise ratios than were obtained in our previous multiwavelength monitoring of this galaxy in 1988-89. IUE spectra were obtained once every two days for a period of 74 days beginning on 14 March 1993. During the last 39 days of this campaign, spectroscopic observations were also made with the HST Faint Object Spectrograph (FOS) on a daily basis. Ground-based observations, consisting of 165 optical spectra and 77 photometric observations (both CCD imaging and aperture photometry), are reported for the period 1992 October to 1993 September, although much of the data are concentrated around the time of the satellite-based program. These data constitute a fifth year of intensive optical monitoring of this galaxy. In this contribution, we describe the acquisition and reduction of all of the satellite and ground-based data obtained in this program. We describe in detail various photometric problems with the FOS and explain how we identified and corrected for various anomalies. During the HST portion of the monitoring campaign, the 1350 A continuum flux is found to have varied by nearly a factor of two. In other wavebands, the continuum shows nearly identical behavior, except that the amplitude of variability is larger at shorter wavelengths, and the continuum light curves appear to show more short time-scale variability at shorter wavelengths. The broad emission lines also vary in flux, with amplitudes that are slightly smaller than the UV continuum variations and with a small time delay relative to the UV continuum. On the basis of simple time-series analysis of the UV and optical continuum and emission line light curves, we find (1) that the ultraviolet and optical continuum variations are virtually simultaneous, with any lag between the 1350 A continuum and the 5100 A continuum amounting to less than about one day; (2) that the variations in the highest ionization lines observed, He II lambda 1640 and N V lambda 1240, lag behind the continuum variations by somewhat less than 2 days, and (3) that the velocity field of the C IV-emitting region is not dominated by radial motion. The results on the C IV velocity field are preliminary and quite uncertain, but there are some weak indications that the emission-line (wings absolute value of Delta upsilon is greater than or equal to 3000 km/s) respond to continuum variations slightly more rapidly than does the core. The optical observations show that the variations in the broad H beta line flux follow the continuum variations with a time lag of around two weeks, about twice the lag for Ly alpha and C IV, as in our previous monitoring campaign on this same galaxy. However, the lags measured for Ly alpha, C IV, and H Beta are each slightly smaller than previously determined. We confirm two trends reported earlier, namely (1) that the UV/optical continuum becomes 'harder' as it gets brighter, and (2) that the highest ionization emission lines have the shortest lags, thus indicating radial ionization stratificatin of a broad-line region that spans over an order of magnitude range in radius.

Korista, K.; Alloin, D.; Barr, P. (e6889478); Clavel, J.; Cohen, R. D.; Crenshaw, D. M.; Evans, I. N.; Horne, K.; Koratkar, A. P.; Kriss, G. A.

1994-01-01

265

Using scissors to bisect a line: a perception-action dissociation in complex tool use.  

PubMed

Previous research has shown that unilateral visual neglect is improved when patients are required to actively grasp an object at its center, rather than only pointing to its center. A similar dissociation between pointing and grasping responses has been reported for pseudoneglect, a spatial bias toward the left side of space that is normally exhibited by healthy participants. Among other theories, the two-visual-streams hypothesis has been offered as an explanation for these dissociations. According to this hypothesis, highly practiced actions that are performed under easily available visual input (e.g., grasping an object) are controlled by the dorsal stream and can resist perceptual judgment biases. We investigated whether, in pseudoneglect, dissociations between perceptual judgments and motor-manipulative responses occur when participants have to respond with complex tools that are highly practiced but that have been shown to rely on both ventral- and dorsal-stream processing. In a standard line bisection task, participants had to either mark the center of a line with a pencil or cut the line in two halves using a pair of scissors. The results indicated the typical leftward bias (pseudoneglect) in the pencil task, whereas performance was much more accurate in the scissors task. These results show that actions featuring complex tool use can resist perceptual judgment biases, and the findings are discussed with reference to existing accounts of perception-action dissociations. PMID:24132710

Massen, Cristina; Rieger, Martina; Sülzenbrück, Sandra

2014-01-01

266

Unraveling the Mysteries of Complex Interstellar Organic Chemistry Using Hifi Line Surveys  

NASA Astrophysics Data System (ADS)

We are undertaking a Herschel Space Observatory OT1 program to conduct HIFI spectral line surveys of interstellar clouds to probe the influence of physical environment on molecular complexity. We will observe a large sample of sources, cover a range of physical environments, and target selected frequency windows containing transitions from several known complex organic molecules. We have an ongoing complementary program in ground-based astronomy using the Caltech Submillimeter Observatory to collect spectral line surveys at lower frequencies, and plan to undertake additional interferometric observations using the CARMA and ALMA arrays to further examine the spatial distributions of the molecules detected toward our target sources. The goal of these observations is to correlate the relative abundances of organic molecules with the physical properties of the source (i.e. temperature, density, age, dynamics, etc.). Our broader research goal is to improve astrochemical models to the point where accurate predictions of complex molecular inventory can be based on the physical and chemical environment of a given source. The information gained from these observations will serve as a benchmark for these astrochemical models and holds the promise of significantly advancing our understanding of interstellar chemical processes. In this talk, we will overview the major goals of this observational program, and report on any preliminary results from these ongoing observations.

Weaver, Susanna L. Widicus; Radhuber, Mary L.; Kroll, Jay A.; McGuire, Brett A.; Laas, Jacob C.; Lis, Darek C.; Herbst, Eric

2011-06-01

267

Titanium(IV) Complexes : Cytotoxicity and Cellular Uptake of Titanium(IV) Complexes on Caco-2 Cell Line  

PubMed Central

Replacement of the ancillary ligand in titanocene dichloride by amino acids provides titanocene species with high water solubility. As part of our research efforts in the area of titanium-based antitumor agents, we have investigated the cytotoxic activity of Cp2TiCl2 and three water soluble titanocene-amino acid complexes—[Cp2Ti(aa)2]Cl2 (aa = L-cysteine, L-methionine, and D-penicillamine) and one water soluble coordination compound, [Ti4(maltolato)8(?-O)4] on the human colon adenocarcinoma cell line, Caco-2. At pH of 7.4 all titanocene species decompose extensively while [Ti4(maltolato)8(?-O)4] is stable for over seven days. In terms of cytotoxicity, the [Cp2Ti(aa)2]Cl2 and [Ti4(maltolato)8(?-O)4] complexes exhibited slightly higher toxicity than titanocene dichloride at 24 hours, but at 72 hours titanocene dichloride and [Ti4(maltolato)8(?-O)4] have higher cytotoxic activity. Cellular Titanium uptake was quantified at various time intervals to investigate the possible relationship between Ti uptake and cellular toxicity. Results indicated that there was not a clear relationship between Ti uptake and cytotoxicity. A structure-activity relationship is discussed.

Hernandez, Ramon; Mendez, Janet; Lamboy, Jose; Torres, Madeline; Roman, Feliz R.; Melendez, Enrique

2009-01-01

268

Line Shape Parameters for CO_2 Transitions: Accurate Predictions from Complex Robert-Bonamy Calculations  

NASA Astrophysics Data System (ADS)

A model for the prediction of the vibrational dependence of CO_2 half-widths and line shifts for several broadeners, based on a modification of the model proposed by Gamache and Hartmann, is presented. This model allows the half-widths and line shifts for a ro-vibrational transition to be expressed in terms of the number of vibrational quanta exchanged in the transition raised to a power p and a reference ro-vibrational transition. Complex Robert-Bonamy calculations were made for 24 bands for lower rotational quantum numbers J'' from 0 to 160 for N_2-, O_2-, air-, and self-collisions with CO_2. In the model a Quantum Coordinate is defined by (c_1 ??_1 + c_2 ??_2 + c_3 ??_3)^p where a linear least-squares fit to the data by the model expression is made. The model allows the determination of the slope and intercept as a function of rotational transition, broadening gas, and temperature. From these fit data, the half-width, line shift, and the temperature dependence of the half-width can be estimated for any ro-vibrational transition, allowing spectroscopic CO_2 databases to have complete information for the line shape parameters. R. R. Gamache, J.-M. Hartmann, J. Quant. Spectrosc. Radiat. Transfer. {{83}} (2004), 119. R. R. Gamache, J. Lamouroux, J. Quant. Spectrosc. Radiat. Transfer. {{117}} (2013), 93.

Lamouroux, Julien; Gamache, Robert R.

2013-06-01

269

Structural Insight into Potent Broad-Spectrum Inhibition with Reversible Recyclization Mechanism: Avibactam in Complex with CTX-M-15 and Pseudomonas aeruginosa AmpC ?-Lactamases  

PubMed Central

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.

Mangani, Stefano; Durand-Reville, Thomas; Benvenuti, Manuela; De Luca, Filomena; Sanyal, Gautam

2013-01-01

270

Cytotoxicity evaluation of vancomycin and its complex with beta-cyclodextrin on human glial cell line.  

PubMed

The possible cytotoxic effects of vancomycin and its complex with beta-cyclodextrin (?-CD) on human glial cell line (CRL 8621) were studied accordingly by means of MTS assay. The cultured cells were incubated with various concentrations of vancomycin, ?-CD as well as ?-CD/vancomycin complex ranging from 4.69 to 300 ug/ml. A linear dose-dependency cytotoxicity followed by hermetic-like biphasic dose-dependence was observed after incubation period of 72 hours. In general, significant increase (p<0.001) of cell proliferation was observed at lower concentrations: <18.75 ?g/ml for cells treated with ?-CD and their complex while < 9.38 ?g/ml for cells treated with vancomycin. In contrary, regardless of the treatments given, significant (p<0.001) reduce in cell survival was found at higher concentrations >150 ?g/ml. In particular, 50 % inhibitory in vitro was achieved at the concentrations of 115.95 ?g/ml (for ?-CD), 116.48 ?g/ml (for vancomycin) and 115.44 ?g/ml (for ?-CD/vancomycin complex). PMID:23010001

Sofian, Zarif Mohamed; Abdullah, Jafri Malin; Rahim, Afidah Abdul; Shafee, Shazrin Shazira; Mustafa, Zulkifli; Razak, Shariza Abdul

2012-10-01

271

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

272

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

PubMed

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 between the obtained chromatograms in both configurations. For on-line analysis of reactor effluents, a dedicated sampling system allows automatic sampling of the hot reactor effluent gases and immediate injection of the sample on the GC × GC. To determine a complete effluent composition in a single run of the GC × GC, a subzero oven starting temperature was employed. Modulation is started when the oven temperature reaches 40°C, thus dividing the chromatogram in a conventional 1D and a comprehensive 2D part. This work illustrates the mature and robust character of GC × GC, extending its capabilities from mere laboratory use to on-line routine analysis for industrial processes in the (petro-)chemical industry. PMID:20444456

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

2010-10-22

273

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

274

Broad-band beam buncher  

DOEpatents

A broad-band beam buncher 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-band response and the device as a whole designed to effect broad-band beam coupling, so as to minimize variations of the output across the response band.

Goldberg, David A. (Walnut Creek, CA); Flood, William S. (Berkeley, CA); Arthur, Allan A. (Martinez, CA); Voelker, Ferdinand (Orinda, CA)

1986-01-01

275

Differential effects of a complex organochlorine mixture on the proliferation of breast cancer cell lines  

SciTech Connect

Organochlorine compounds (OCs) are a group of persistent chemicals that accumulate in fatty tissues with age. Although OCs has been tested individually for their capacity to induce breast cancer cell proliferation, few studies examined the effect of complex mixtures that comprise compounds frequently detected in the serum of women. We constituted such an OC mixture containing 15 different components in environmentally relevant proportions and assessed its proliferative effects in four breast cancer cell lines (MCF-7, T47D, CAMA-1, MDAMB231) and in non-cancerous CV-1 cells. We also determined the capacity of the mixture to modulate cell cycle stage of breast cancer cells and to induce estrogenic and antiandrogenic effects using gene reporter assays. We observed that low concentrations of the mixture (100x10{sup 3} and 50x10{sup 3} dilutions) stimulated the proliferation of MCF-7 cells while higher concentrations (10x10{sup 3} and 5x10{sup 3} dilutions) had the opposite effect. In contrast, the mixture inhibited the proliferation of non-hormone-dependent cell lines. The mixture significantly increased the number of MCF-7 cells entering the S phase, an effect that was blocked by the antiestrogen ICI 182,780. Low concentrations of the mixture also caused an increase in CAMA-1 cell proliferation but only in the presence estradiol and dihydrotestosterone (p<0.05 at the 50x10{sup 3} dilution). DDT analogs and polychlorinated biphenyls all had the capacity to stimulate the proliferation of CAMA-1 cells in the presence of sex steroids. Reporter gene assays further revealed that the mixture and several of its constituents (DDT analogs, aldrin, dieldrin, {beta}-hexachlorocyclohexane, toxaphene) induced estrogenic effects, whereas the mixture and several components (DDT analogs, aldrin, dieldrin and PCBs) inhibited the androgen signaling pathway. Our results indicate that the complex OC mixture increases the proliferation of MCF-7 cells due to its estrogenic potential. The proliferative effect of the mixture on CAMA-1 cells in the presence of sex steroids appears mostly due to the antiandrogenic properties of p,p'-DDE, a major constituent of the mixture. Other mixtures of contaminants that include emerging compounds of interest such as brominated flame retardants and perfluoroalkyl compounds should be tested for their capacity to induce breast cancer cell proliferation. - Research highlights: {yields} We studied effects of a complex organochlorine mixture on breast cancer cell growth. {yields} Weak xenoestrogens in the mixture stimulated the proliferation of MCF-7 cells. {yields} Antiandrogens increased the proliferation CAMA-1 cells grown with sex steroids. {yields} High concentrations of the mixture decreased the proliferation of all cell lines.

Aube, Michel, E-mail: 4aubem@videotron.ca [Axe de recherche en sante des populations et environnementale, Centre de recherche du Centre hospitalier universitaire de Quebec and Universite Laval, 2875 Boulevard Laurier, Edifice Delta 2, bureau 600, Quebec, QC, Canada G1V 2M2 (Canada)] [Axe de recherche en sante des populations et environnementale, Centre de recherche du Centre hospitalier universitaire de Quebec and Universite Laval, 2875 Boulevard Laurier, Edifice Delta 2, bureau 600, Quebec, QC, Canada G1V 2M2 (Canada); Larochelle, Christian, E-mail: christian.larochelle@inspq.qc.ca [Axe de recherche en sante des populations et environnementale, Centre de recherche du Centre hospitalier universitaire de Quebec and Universite Laval, 2875 Boulevard Laurier, Edifice Delta 2, bureau 600, Quebec, QC, Canada G1V 2M2 (Canada)] [Axe de recherche en sante des populations et environnementale, Centre de recherche du Centre hospitalier universitaire de Quebec and Universite Laval, 2875 Boulevard Laurier, Edifice Delta 2, bureau 600, Quebec, QC, Canada G1V 2M2 (Canada); Ayotte, Pierre, E-mail: pierre.ayotte@inspq.qc.ca [Axe de recherche en sante des populations et environnementale, Centre de recherche du Centre hospitalier universitaire de Quebec and Universite Laval, 2875 Boulevard Laurier, Edifice Delta 2, bureau 600, Quebec, QC, Canada G1V 2M2 (Canada) [Axe de recherche en sante des populations et environnementale, Centre de recherche du Centre hospitalier universitaire de Quebec and Universite Laval, 2875 Boulevard Laurier, Edifice Delta 2, bureau 600, Quebec, QC, Canada G1V 2M2 (Canada); Laboratoire de Toxicologie, Institut national de sante publique du Quebec, 945 avenue Wolfe, Quebec, QC, Canada G1V 5B3 (Canada)

2011-04-15

276

Antiproliferative effects of metal complexes of new isatin hydrazones against HCT116, MCF7 and HELA tumour cell lines.  

PubMed

New hydrazone ligands (HL) derived from 5-substituted isatins and 1-(4-(2-methoxybenzyl)-6-arylpyridazin-3-yl)hydrazines and its complexes with Co(II) and Cu(II) were synthesized. The new hydrazones and their complexes were characterized by means of elemental, spectral analyses and magnetic studies. Primary cytotoxicity evaluation of HL 5a and the new complexes showed that these complexes could act as anticancer agents since they reduced the growth of samples of human tumour cell lines (HCT116((Colon)), MCF7((Breast)) and HELA((Cervix))) to ?18.5 ?g/mL for the new complexes. PMID:21699460

Kandile, Nadia G; Mohamed, Mansoura I; Ismaeel, Hind M

2012-06-01

277

The Structure of the Glial Cell Line-derived Neurotrophic Factor-Coreceptor Complex  

PubMed Central

Glial cell line-derived neurotrophic factor (GDNF), a neuronal survival factor, binds its co-receptor GDNF family receptor ?1 (GFR?1) in a 2:2 ratio and signals through the receptor tyrosine kinase RET. We have solved the GDNF2·GFR?12 complex structure at 2.35 Å resolution in the presence of a heparin mimic, sucrose octasulfate. The structure of our GDNF2·GFR?12 complex and the previously published artemin2·GFR?32 complex are unlike in three ways. First, we have experimentally identified residues that differ in the ligand-GFR? interface between the two structures, in particular ones that buttress the key conserved ArgGFR?-Gluligand-ArgGFR? interaction. Second, the flexible GDNF ligand “finger” loops fit differently into the GFR?s, which are rigid. Third, and we believe most importantly, the quaternary structure of the two tetramers is dissimilar, because the angle between the two GDNF monomers is different. This suggests that the RET-RET interaction differs in different ligand2-co-receptor2-RET2 heterohexamer complexes. Consistent with this, we showed that GDNF2·GFR?12 and artemin2·GFR?32 signal differently in a mitogen-activated protein kinase assay. Furthermore, we have shown by mutagenesis and enzyme-linked immunosorbent assays of RET phosphorylation that RET probably interacts with GFR?1 residues Arg-190, Lys-194, Arg-197, Gln-198, Lys-202, Arg-257, Arg-259, Glu-323, and Asp-324 upon both domains 2 and 3. Interestingly, in our structure, sucrose octasulfate also binds to the Arg190-Lys202 region in GFR?1 domain 2. This may explain how GDNF·GFR?1 can mediate cell adhesion and how heparin might inhibit GDNF signaling through RET.

Parkash, Vimal; Leppanen, Veli-Matti; Virtanen, Heidi; Jurvansuu, Jaana M.; Bespalov, Maxim M.; Sidorova, Yulia A.; Runeberg-Roos, Pia; Saarma, Mart; Goldman, Adrian

2008-01-01

278

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

279

P granules extend the nuclear pore complex environment in the C. elegans germ line  

PubMed Central

The immortal and totipotent properties of the germ line depend on determinants within the germ plasm. A common characteristic of germ plasm across phyla is the presence of germ granules, including P granules in Caenorhabditis elegans, which are typically associated with the nuclear periphery. In C. elegans, nuclear pore complex (NPC)–like FG repeat domains are found in the VASA-related P-granule proteins GLH-1, GLH-2, and GLH-4 and other P-granule components. We demonstrate that P granules, like NPCs, are held together by weak hydrophobic interactions and establish a size-exclusion barrier. Our analysis of intestine-expressed proteins revealed that GLH-1 and its FG domain are not sufficient to form granules, but require factors like PGL-1 to nucleate the localized concentration of GLH proteins. GLH-1 is necessary but not sufficient for the perinuclear location of granules in the intestine. Our results suggest that P granules extend the NPC environment in the germ line and provide insights into the roles of the PGL and GLH family proteins.

Updike, Dustin L.; Hachey, Stephanie J.; Kreher, Jeremy

2011-01-01

280

The line-of-sight distribution of water in the SgrB2 complex  

NASA Astrophysics Data System (ADS)

We report the detection, with the Caltech Submillimeter Observatory, of the 894-GHz HDO(11,1-00,0) transition, observed in absorption against the background continuum emission of the SgrB2 cores M and N. Radiative transfer modeling of this feature, together with the published data set of mm and submm HDO and \\WATEIGH transitions, suggests that ground-state absorption features from deuterated and non-deuterated water trace different gas components along the line of sight. In particular, while the HDO line seems to be produced by the large column densities of gas located in the SgrB2 warm envelope, the \\WATEIGH ground-state transition detected by SWAS and KAO at 548 GHz (Neufeld et al. \\cite{neufeld2000}; Zmuidzinas et al. \\cite{zmuidzi95a}) is instead a product of the hot, diffuse, thin gas layer lying in the foreground of the SgrB2 complex. The CSO is operated by the California Institute of Technology under funding from the National Science Foundation, Grant No. AST-9980846.

Comito, C.; Schilke, P.; Gerin, M.; Phillips, T. G.; Zmuidzinas, J.; Lis, D. C.

2003-05-01

281

Petrogenesis of the Sabongari alkaline complex, cameroon line (central Africa): Preliminary petrological and geochemical constraints  

NASA Astrophysics Data System (ADS)

The petrography, mineral chemistry and geochemical features of the Sabongari alkaline complex are presented and discussed in this paper with the aim of constraining its petrogenesis and comparing it with other alkaline complexes of the Cameroon Line. The complex is mainly made up of felsic rocks: (i) granites predominate and include pyroxene-amphibole (the most abundant), amphibole-biotite, biotite and pyroxene types; (ii) syenites are subordinate and comprise amphibole-pyroxene and amphibole-biotite quartz syenites; (iii) pyroxene-amphibole-biotite trachyte and (iv) relatively abundant rhyolite. The minor basic and intermediate terms associated with felsic rocks consist of basanites, microdiorite and monzodioites. Two groups of pyroxene bearing rocks are distinguished: a basanite-trachyte-granite (Group 1) bimodal series (SiO2 gap: 44 and 63 wt.%) and a basanite-microdiorite-monzodiorite-syenite-granite (Group 2) less pronounced bimodal series (reduced SiO2 gap: 56-67 wt.%). Both are metaluminous to peralkaline whereas felsic rocks bare of pyroxene (Group 3) are metaluminous to peraluminous. The Group 1 basanite is SiO2-undersaturated (modal analcite in the groundmass and 11.04 wt.% normative nepheline); its Ni (240 ppm) and Cr (450 ppm) contents, near mantle values, indicate its most primitive character. The Group 2 basanite is rather slightly SiO2-saturated (1.56 wt.% normative hypersthene), a marker of its high crustal contamination (low Nb/Y-high Rb/Y). The La/Yb and Gd/Yb values of both basanites (1: 19.47 and 2.92; 2: 9.09 and 2.23) suggest their common parental magma composition, and their crystallization through two episodes of partial melting (2% and 3% respectively) of a lherzolite mantle source with <4% residual garnet. The effects of crustal contamination were selectively felt in the values of HFSE/LREE, LREE/LILE and LREE/HFSE ratios, known as indicators. Similar features have been recently obtained in the felsic lavas of the Cameroon Volcanic Line.

Njonfang, Emmanuel; Tchoneng, Gilbert Tchuenté; Cozzupoli, Domenico; Lucci, Federico

2013-07-01

282

Differential effects of a complex organochlorine mixture on the proliferation of breast cancer cell lines.  

PubMed

Organochlorine compounds (OCs) are a group of persistent chemicals that accumulate in fatty tissues with age. Although OCs has been tested individually for their capacity to induce breast cancer cell proliferation, few studies examined the effect of complex mixtures that comprise compounds frequently detected in the serum of women. We constituted such an OC mixture containing 15 different components in environmentally relevant proportions and assessed its proliferative effects in four breast cancer cell lines (MCF-7, T47D, CAMA-1, MDAMB231) and in non-cancerous CV-1 cells. We also determined the capacity of the mixture to modulate cell cycle stage of breast cancer cells and to induce estrogenic and antiandrogenic effects using gene reporter assays. We observed that low concentrations of the mixture (100 × 10(3) and 50 × 10(3) dilutions) stimulated the proliferation of MCF-7 cells while higher concentrations (10 × 10(3) and 5 × 10(3) dilutions) had the opposite effect. In contrast, the mixture inhibited the proliferation of non-hormone-dependent cell lines. The mixture significantly increased the number of MCF-7 cells entering the S phase, an effect that was blocked by the antiestrogen ICI 182,780. Low concentrations of the mixture also caused an increase in CAMA-1 cell proliferation but only in the presence estradiol and dihydrotestosterone (p<0.05 at the 50 × 10(3) dilution). DDT analogs and polychlorinated biphenyls all had the capacity to stimulate the proliferation of CAMA-1 cells in the presence of sex steroids. Reporter gene assays further revealed that the mixture and several of its constituents (DDT analogs, aldrin, dieldrin, ?-hexachlorocyclohexane, toxaphene) induced estrogenic effects, whereas the mixture and several components (DDT analogs, aldrin, dieldrin and PCBs) inhibited the androgen signaling pathway. Our results indicate that the complex OC mixture increases the proliferation of MCF-7 cells due to its estrogenic potential. The proliferative effect of the mixture on CAMA-1 cells in the presence of sex steroids appears mostly due to the antiandrogenic properties of p,p'-DDE, a major constituent of the mixture. Other mixtures of contaminants that include emerging compounds of interest such as brominated flame retardants and perfluoroalkyl compounds should be tested for their capacity to induce breast cancer cell proliferation. PMID:21295777

Aubé, Michel; Larochelle, Christian; Ayotte, Pierre

2011-04-01

283

Magnetic connections of solar formations inside magneto-isolated complexes based on observations of arch structures and calculations of magnetic field lines  

NASA Astrophysics Data System (ADS)

The magnetic connections of solar formations inside magneto-isolated complexes with areas outside the complexes were determined from the loop structures in the upper chromosphere and corona, as well as from calculations of magnetic field lines. It was found that 65% of the constructed field lines are closed within complexes or not closed on the solar surface, while 35% of the field lines intersect the boundary of the complex. Short field lines that intersect the boundary of the complex often connect the points of low intensity. The ends of the long field lines coincide with ends of the arch structures, whose higher parts are not visible in the 17.1 nm line. The short field lines coincide in position with the loop structures at the corona level. It was shown that there are three types of magnetic field variations depending on the height above the complexes.

Fainshtein, V. G.; Malashchuk, V. M.; Stepanian, N. N.; Rudenko, G. V.; Egorov, Ya. I.

2013-06-01

284

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

285

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

286

Electron–phonon and vibronic couplings in the FMO bacteriochlorophyll a antenna complex studied by difference fluorescence line narrowing  

Microsoft Academic Search

The electron–phonon and vibronic couplings governing the spectral properties have been studied in the Fenna–Matthews–Olson (FMO) bacteriochlorophyll a (BChl a)–protein complex at 4.5K using a spectrally selective difference fluorescence line-narrowing technique. The complex is a part of the light-harvesting system of green photosynthetic bacteria. Its lowest-energy absorption band, peaking at 826nm and responsible for the fluorescence, is believed to be

Margus Rätsep; Arvi Freiberg

2007-01-01

287

Liquid chromatography of tin-reduced technetium hydroxyethylidene diphosphonate complexes for on-line spectral characterization and double isotope labeling  

Microsoft Academic Search

An anion-exchange high-performance liquid chromatographic separation has been developed for tin-reduced technetium hydroxyethylidene diphosphonate complexes, Tc-HEDP, at millimolar concentrations of technetium-99. The separation facilitates the acquisition of ultraviolet-visible spectra of the Tc-HEDP complexes on-line with a diode array spectrophotometer. A precolumn backflush technique has been devised to remove unreacted pertechnetate from the chromatographic system after each injection, thus preventing on-column

Martin V. Mikelsons; Thomas C. Pinkerton

1986-01-01

288

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

289

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

290

Concentrations of clarithromycin and active metabolite in the epithelial lining fluid of patients with Mycobacterium avium complex pulmonary disease  

Microsoft Academic Search

ObjectivesClarithromycin (CAM) is widely accepted for the treatment of Mycobacterium avium complex (MAC) pulmonary diseases. This study measured (a) the concentrations of CAM and its active metabolite (14OH-CAM) in bronchial epithelial lining fluid (ELF) obtained by bronchoscopic microsampling (BMS), and (b) the minimal inhibitory concentrations (MIC) of CAM for each MAC isolate.

Naoki Hasegawa; Tomoyasu Nishimura; Masazumi Watabnabe; Sadatomo Tasaka; Yasushi Nakano; Koichi Yamazaki; Satoru Hashimoto; Masahiro Nishimura; Akitoshi Ishizaka

2009-01-01

291

Somatic and Occult Germ-line Mutations in SDHD, a Mitochondrial Complex II Gene, in Nonfamilial Pheochromocytoma1  

Microsoft Academic Search

Most pheochromocytomas are sporadic but about 10% are thought to be hereditary. Although the etiology of most inherited pheochromocy- toma is well known, little is known about the etiology of the more common sporadic tumor. Recently, germ-line mutations of SDHD, a mitochondrial complex II gene, were found in patients with hereditary paraganglioma. We sought to determine whether SDHD plays a

Oliver Gimm; Mary Armanios; Heather Dziema; Hartmut P. H. Neumann; Charis Eng

292

The iron Kalpha line complex in Compton-thick Seyfert 2 galaxies  

NASA Astrophysics Data System (ADS)

We calculate the intensities of the fluorescent and resonantly scattered iron Kalpha lines in those active galactic nuclei (AGN) in which the primary radiation at the line energy is completely blocked by intervening matter along the line of sight (the so-called `Compton-thick' Seyfert 2 galaxies). In the framework of unification models for Seyfert galaxies, both a `cold' fluorescent line from the obscuring torus and highly ionized lines from the warm material responsible for the scattering and polarization of optical photons are expected. The neutral iron line from the obscuring torus has an equivalent width, with respect to the continuum reflected by the same matter, of order 1-2 keV, provided that the matter is Compton thick. The line emission from the warm material, in the optically thin regime for all relevant processes, is dominated by the resonantly scattered lines. However, for plausible physical conditions of this matter, the resonant lines are likely to be optically thick in their centres. In this case, the resonant line intensity can significantly decrease, and for tau_T>~0.1 the fluorescent/recombination lines dominate the resonant lines. We present analytical formulae for the equivalent widths of iron lines in the optically thin case, and numerical results (obtained by means of Monte Carlo simulations) for the optically thick case. We apply the theoretical results to the most famous Compton-thick source, the Seyfert 2 galaxy NGC 1068. The large uncertainties in the continuum spectral shape and line equivalent widths prevent any definite conclusions, but the application can be regarded as an example of how the results presented in this paper could be used to estimate physical and geometrical quantities in obscured AGN.

Matt, G.; Brandt, W. N.; Fabian, A. C.

1996-06-01

293

Liquid chromatography of tin-reduced technetium hydroxyethylidene diphosphonate complexes for on-line spectral characterization and double isotope labeling  

SciTech Connect

An anion-exchange high-performance liquid chromatographic separation has been developed for tin-reduced technetium hydroxyethylidene diphosphonate complexes, Tc-HEDP, at millimolar concentrations of technetium-99. The separation facilitates the acquisition of ultraviolet-visible spectra of the Tc-HEDP complexes on-line with a diode array spectrophotometer. A precolumn backflush technique has been devised to remove unreacted pertechnetate from the chromatographic system after each injection, thus preventing on-column reactions from subsequent samples containing Sn(II). The Tc-HEDP complexes were prepared at pH 2.5, 7.3 and 10.0 to demonstrate the effect of pH on the distribution of complexes within the separation. The reactions produce from four to five primary complexes, which vary as a function of pH. Some 13 additional complexes are present in trace amounts. The reactions were carried out with /sup 113/Sn to determine if tin is incorporated into the complexes. Only one minor complex was found to contain tin. The ultraviolet-visible spectral characteristics of 10 Tc-HEDP complexes are reported. 27 references, 8 figures, 2 tables.

Mikelsons, M.V.; Pinkerton, T.C.

1986-05-01

294

COS Observations of Metal Line and Broad Lyman-? Absorption in the Multi-phase O VI and Ne VIII System at z = 0.20701 toward HE 0226-4110  

NASA Astrophysics Data System (ADS)

Observations of the QSO HE 0226-4110 (z em = 0.495) with the Cosmic Origins Spectrograph (COS) from 1134 to 1796 Å with a resolution of ~17 km s-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? (BLA) absorption with b = 72(+13, -6) km s-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 ~ 5.7 that also produces the O VI and Ne VIII absorption. The total hydrogen column in the collisionally ionized gas, log N(H) ~ 20.1, exceeds that in the cooler photoionized gas in the system by a factor of ~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 * disk galaxy with an impact parameter of 109 h 70 -1 kpc identified by Mulchaey & Chen. Based on observations obtained with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS5-26555, and the NASA-CNES/ESA Far Ultraviolet Spectroscopic Explorer mission operated by Johns Hopkins University, supported by NASA contract NAS 05-32985.

Savage, B. D.; Lehner, N.; Narayanan, A.

2011-12-01

295

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

296

Line bundle twisted chiral de Rham complex and bound states of D-branes on toric manifolds  

NASA Astrophysics Data System (ADS)

In this note we calculate elliptic genus in various examples of twisted chiral de Rham complex on two-dimensional toric compact manifolds and Calabi-Yau hypersurfaces in toric manifolds. At first the elliptic genus is calculated for the line bundle twisted chiral de Rham complex on a compact smooth toric manifold and K3 hypersurface in P3. Then we twist chiral de Rham complex by sheaves localized on positive codimension submanifolds in P2 and calculate in each case the elliptic genus. In the last example the elliptic genus of chiral de Rham complex on P2 twisted by SL(N) vector bundle with instanton number k is calculated. In all the cases considered we find the infinite tower of open string oscillator contributions and identify directly the open string boundary conditions of the corresponding bound state of D-branes.

Parkhomenko, S. E.

2014-04-01

297

Interferon gamma regulates binding of two nuclear protein complexes in a macrophage cell line.  

PubMed Central

Interferon gamma (IFN-gamma) is a potent inducer of major histocompatibility complex (MHC) antigens during normal immune responses and in abnormal responses in autoimmune disease. In this report we identify two nuclear factors whose binding to the murine E beta class II MHC beta-chain gene is regulated by this cytokine. IFN-gamma stimulation of murine macrophages results in the appearance of increased binding of one protein complex, complex A, and decreased binding of a second, faster migrating protein complex, complex B. Although the contact residues for both of these proteins lie within the highly conserved Y-box transcriptional element, their binding specificity differs. The protein in complex B is a CCAAT-box-binding protein that may be similar or identical to NF-Y or YB1, previously identified class II Y-box-binding proteins. The DNA sequence requirements for the binding of the slower migrating complex, complex A, are not limited to CCAAT-box sequences but include sequences upstream of the Y box. These upstream sequences are required both for IFN-gamma-induced gene transcription and for IFN-gamma-induced modulation of binding activity. These data suggest a model in which upstream sequences contribute to formation of a lymphokine-regulated complex downstream. The IFN-gamma-induced binding protein described as complex A in this report differs from the IFN-gamma, -alpha, or -beta-induced nuclear factors previously identified. Images

Finn, P W; Kara, C J; Douhan, J; Van, T T; Folsom, V; Glimcher, L H

1990-01-01

298

Line tension and stability of domains in cell-adhesion zones mediated by long and short receptor-ligand complexes.  

PubMed

Submicron scale domains of membrane-anchored receptors play an important role in cell signaling. Central questions concern the stability of these microdomains, and the mechanisms leading to the domain formation. In immune-cell adhesion zones, microdomains of short receptor-ligand complexes form next to domains of significantly longer receptor-ligand complexes. The length mismatch between the receptor-ligand complexes leads to membrane deformations and has been suggested as a possible cause of the domain formation. The domain formation is a nucleation and growth process that depends on the line tension and free energy of the domains. Using a combination of analytical calculations and Monte Carlo simulations, we derive here general expressions for the line tension between domains of long and short receptor-ligand complexes and for the adhesion free energy of the domains. We argue that the length mismatch of receptor-ligand complexes alone is sufficient to drive the domain formation, and obtain submicron-scale minimum sizes for stable domains that are consistent with the domain sizes observed during immune-cell adhesion. PMID:21858057

Krobath, Heinrich; Ró?ycki, Bartosz; Lipowsky, Reinhard; Weikl, Thomas R

2011-01-01

299

Comparative properties of the nuclear aryl hydrocarbon (Ah) receptor complex from several human cell lines  

Microsoft Academic Search

The aryl hydrocarbon (Ah) responsiveness of the T-47D, Hep G2, LS180, MCF-7, A431, C-4II and MDA-MB-231 human cancer cell lines was determined by the induction of CYP1A1 mRNA levels and ethoxyresorufin O-deethylase activity. With the exception of the MDA-MB-231 breast cancer cell line, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) significantly induced CYP1A1 mRNA levels and ethoxyresorufin O-deethylase activity in the remaining six cell lines

Xiaohong Wang; Jane S. Thomsen; Michael Santostefano; Rhonda Rosengren; Stephen Safe; Gary H. Perdew

1995-01-01

300

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 6-8 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, Anthony J. (Nesconset, NY); Hyer, Ronald C. (Los Alamos, NM); Shapiro, Stanley J. (Los Alamos, NM)

1982-01-01

301

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

302

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

303

Full-wave analysis of nonplanar transmission lines on layered medium by means of MPIE and complex image theory  

Microsoft Academic Search

In this paper, a multiconductor transmission line consisting of arbitrary cross-sectional perfect conductors printed on a layered isotropic or uniaxial anisotropic dielectric medium is analyzed by solving the mixed-potential integral equation for the free-surface currents. Closed-form expressions of the two-dimensional space-domain Green's functions for the electrodynamic potentials are used. These expressions are obtained by applying the complex image technique to

Joaquin Bernal; Francisco Medina; Rafael R. Boix

2001-01-01

304

BRG1, a Component of the SWI-SNF Complex, Is Mutated in Multiple Human Tumor Cell Lines  

Microsoft Academic Search

Human BRG1 is a component of the evolutionarily conserved SWI-SNF chromatin remodeling complex. BRG1 has been implicated in growth control through its interaction with the tumor suppressor pRb and may consequently serve as a negative regulator of proliferation. Postulating that BRG1 may itself be a tumor suppressor gene, we screened a panel of tumor cell lines to determine whether the

Alexander K. C. Wong; Frances Shanahan; Yuan Chen; Lubing Lian; Kristin Hendricks; Siavash Ghaffari; Diana Iliev; Brandon Penn; Anne-Marie Woodland; Richard Smith; Arlene Carillo; Kirsten Laity; Jamila Gupte; Brad Swedlund; Sean V. Tavtigian; Emma Lees

305

Complexities of gamma-ray line intensities from the lunar surface  

Microsoft Academic Search

Assuming different abundances of the Apollo lunar soil samples and the average spectrum of galactic cosmic ray protons, energy spectra of neutrons and gamma rays and emission rates of gamma-ray lines from major elements have been estimated by using the reviewed Monte Carlo simulation library Geant4 and nuclear data. Previously, such libraries were not able to reproduce gamma-ray lines properly

N. Yamashita; N. Hasebe; T. Miyachi; M. Kobayashi; O. Okudaira; S. Kobayashi; T. Ishizaki; K. Sakurai; M. Miyajima; R. C. Reedy; C. D'Uston; S. Maurice; O. Gasnault

2008-01-01

306

The Use of On-Line Information Systems in Support of Complex Litigation.  

ERIC Educational Resources Information Center

This paper describes the characteristics of a computerized information retrieval system which could be used by attorneys engaged in such complex litigation as (1) cases which involve multi-district litigation; (2) cases involving complex issues of fact, as in regulatory agency actions; (3) cases involving a large number of documents; and (4) cases…

Emerson, Jeff D.

307

Line bundle twisted chiral de Rham complex, chiral Riemann-Roch formula and D-branes on toric manifolds  

NASA Astrophysics Data System (ADS)

I present the results of the elliptic genus calculations in various examples of twisted chiral de Rham complex on one- and two-dimensional toric compact manifolds. The explicit calculations are made for line bundle twisted chiral de Rham complex on ?1, ?2 and Hirzebruch surface. Based on these results I propose the elliptic genus expression of the bundle twisted chiral de Rham complex for general smooth compact two dimensional toric manifold. The expression resembles Riemann-Roch formula and coincides with the later in certain limit. I interpret the result in terms of infinite tower of open string oscillator contributions and identify directly the open string boundary conditions of the corresponding bound state of D-branes.

Parkhomenko, S. E.

2014-03-01

308

Transvenous removal of an entangled central venous line following complex cardiac surgery.  

PubMed

Unintended internal suturing of central venous lines or pulmonary artery catheters in the superior caval vein or the right atrium following cardiac surgery remains a rare but troublesome complication. The line is normally entangled in safety or hemostasis sutures after the removal of the superior caval cannulation. If mild tension is unsuccessful, the patient normally undergoes resternotomy. The objective of this brief communication is to describe of a simple and safe removal method using a transvenous rotational cutting device to divide the hemostasis suture. In order to avoid complicating bleeding, a time delay between initial placement and removal is highly recommended. For extraction, a fully equipped cardiovascular operating room with central venous and arterial lines, attached defibrillator pads, transesophageal echo monitoring, fluoroscopy, and a surgical team, including a heart and lung machine and a perfusionist standby, is mandatory. PMID:19659633

Sun, Ke; Aebert, Hermann; Stock, Ulrich A; Lisy, Milan; Ziemer, Gerhard; Doernberger, Volker

2009-08-01

309

Emission Line Profiles in T Tauri Stars  

NASA Astrophysics Data System (ADS)

Emission lines in Classical T Tauri stars often have complex kinematic features that suggest a composite origin. We have begun a line profile analysis for 18 classical T Tauri stars based on simultaneous HIRES and NIRSPEC spectra with the goal of identifying kinematic components in different lines and comparing their line ratios to the local line excitation models of Kwan and Fischer (2011). Decomposition of permitted lines in T Tauri stars into broad and narrow components has been a recognized approach since Hamann and Persson (1992). To date, we have decomposed lines of the Paschen series, Ca II infrared triplet, He I 5876 and OI 8446 into multiple Gaussian components. While some lines have simple Gaussian shapes, others require up to three components to describe the observed profiles. We identify commonalities among these three lines and use ratios of similar kinematic components to explore physical conditions in the line-forming region.

Podel, Jennifer; Edwards, S.; Feng, W.

2014-01-01

310

Complex organic molecules in the interstellar medium: IRAM 30 m line survey of Sagittarius B2(N) and (M)  

NASA Astrophysics Data System (ADS)

Context. The discovery of amino acids in meteorites fallen to Earth and the detection of glycine, the simplest of them, in samples returned from a comet to Earth strongly suggest that the chemistry of the interstellar medium is capable of producing such complex organic molecules and that they may be widespread in our Galaxy. Aims: Our goal is to investigate the degree of chemical complexity that can be reached in the interstellar medium, in particular in dense star-forming regions. Methods: We performed an unbiased, spectral line survey toward Sgr B2(N) and (M), two regions where high-mass stars are formed, with the IRAM 30 m telescope in the 3 mm atmospheric transmission window. Partial surveys at 2 and 1.3 mm were performed in parallel. The spectra were analyzed with a simple radiative transfer model that assumes local thermodynamic equilibrium but takes optical depth effects into account. Results: About 3675 and 945 spectral lines with a peak signal-to-noise ratio higher than 4 are detected at 3 mm toward Sgr B2(N) and (M), i.e. about 102 and 26 lines per GHz, respectively. This represents an increase by about a factor of two over previous surveys of Sgr B2. About 70% and 47% of the lines detected toward Sgr B2(N) and (M) are identified and assigned to 56 and 46 distinct molecules as well as to 66 and 54 less abundant isotopologues of these molecules, respectively. In addition, we report the detection of transitions from 59 and 24 catalog entries corresponding to vibrationally or torsionally excited states of some of these molecules, respectively, up to a vibration energy of 1400 cm-1 (2000 K). Excitation temperatures and column densities were derived for each species but should be used with caution. The rotation temperatures of the detected complex molecules typically range from ~50 to 200 K. Among the detected molecules, aminoacetonitrile, n-propyl cyanide, and ethyl formate were reported for the first time in space based on this survey, as were five rare isotopologues of vinyl cyanide, cyanoacetylene, and hydrogen cyanide. We also report the detection of transitions from within twelve new vibrationally or torsionally excited states of known molecules. Absorption features produced by diffuse clouds along the line of sight are detected in transitions with low rotation quantum numbers of many simple molecules and are modeled with ~30-40 velocity components with typical linewidths of ~3-5 km s-1. Conclusions: Although the large number of unidentified lines may still allow future identification of new molecules, we expect most of these lines to belong to vibrationally or torsionally excited states or to rare isotopologues of known molecules for which spectroscopic predictions are currently missing. Significant progress in extending the inventory of complex organic molecules in Sgr B2(N) and deriving tighter constraints on their location, origin, and abundance is expected in the near future thanks to an ongoing spectral line survey at 3 mm with ALMA in its cycles 0 and 1. The present single-dish survey will serve as a solid basis for the line identification and analysis of such an interferometric survey. Based on observations carried out with the IRAM 30 m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).Figures 2-7 and Tables 6-107 are available in electronic form at http://www.aanda.orgThe observed and synthetic 3 mm spectra of Sgr B2(N) and (M), as well as the lists of line identifications corresponding to the blue lab- els in Figs. 2-7, are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/559/A47

Belloche, A.; Müller, H. S. P.; Menten, K. M.; Schilke, P.; Comito, C.

2013-11-01

311

A HIGH-METALLICITY, HIGH-VELOCITY CLOUD ALONG THE Mrk 421 SIGHT LINE: A TRACER OF COMPLEX M?  

SciTech Connect

We present a new measurement, 0.85-3.5 Z{sub 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{sub LSR} = -131 km s{sup -1} is not visible in 21 cm emission (log N{sub H{sub I}} < 18.38; 3{sigma}), it is detected in ultraviolet absorption lines of C II, N I, O I, O VI, Si II, Si III, Si IV, Fe II, and H I. By referencing velocities to the intermediate-velocity cloud at -60 km s{sup -1} and jointly analyzing H I absorption from high-order H I Lyman lines, we measure log N{sub H{sub I}} = 16.84{sup +0.34}{sub -0.13} (1{sigma}) in the HVC. Comparing H I and O I, we find an HVC metallicity [O/H] =0.32{sup +0.22}{sub -0.39}. Because the sight line passes {approx}4{sup 0} from the HVCs in Complex M, the detected HVC may represent the highest velocity component of the Complex, and our measurements provide a lower limit to its metallicity. The high, possibly super-solar metallicity, together with the low distance, z < 3.5 kpc, above the Galactic plane suggests that Complex M is condensed returning gas from a Galactic fountain.

Yao Yangsen; Shull, J. Michael; Danforth, Charles W., E-mail: yaoys@colorado.edu, E-mail: michael.shull@colorado.edu, E-mail: charles.danforth@colorado.edu [Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309 (United States)

2011-02-10

312

Synthesis and Characterization of New Palladium(II) Thiosemicarbazone Complexes and Their Cytotoxic Activity against Various Human Tumor Cell Lines  

PubMed Central

The palladium(II) bis-chelate complexes of the type [Pd(TSC1-5)2] (6–10), with their corresponding ligands 4-phenyl-1-(acetone)-thiosemicarbazone, HTSC1 (1), 4-phenyl-1-(2?-chloro-benzaldehyde)-thiosemicarbazone, HTSC2 (2), 4-phenyl-1-(3?-hydroxy-benzaldehyde)-thiosemicarbazone, HTSC3 (3), 4-phenyl-1-(2?-naphthaldehyde)-thiosemicarbazone, HTSC4 (4), and 4-phenyl-1-(1?-nitro-2?-naphthaldehyde)-thiosemicarbazone, HTSC5 (5), were synthesized and characterized by elemental analysis and spectroscopic techniques (IR and 1H- and 13C-NMR). The molecular structure of HTSC3, HTSC4, and [Pd(TSC1)2] (6) have been determined by single crystal X-ray crystallography. Complex 6 shows a square planar geometry with two deprotonated ligands coordinated to PdII through the azomethine nitrogen and thione sulfur atoms in a cis arrangement. The in vitro cytotoxic activity measurements indicate that the palladium(II) complexes (IC50 = 0.01–9.87??M) exhibited higher antiproliferative activity than their free ligands (IC50 = 23.48–70.86 and >250??M) against different types of human tumor cell lines. Among all the studied palladium(II) complexes, the [Pd(TSC3)2] (8) complex exhibited high antitumor activity on the DU145 prostate carcinoma and K562 chronic myelogenous leukemia cells, with low values of the inhibitory concentration (0.01 and 0.02??M, resp.).

Hernandez, Wilfredo; Paz, Juan; Carrasco, Fernando; Spodine, Evgenia; Manzur, Jorge; Sieler, Joachim; Blaurock, Steffen; Beyer, Lothar

2013-01-01

313

Gas flow sputtering — An approach to coat complex geometries and Non Line of Sight areas  

Microsoft Academic Search

Most PVD techniques are limited in coating complex geometries such as turbine blades without additional substrate manipulation. A novel approach to overcome these limits is the innovative gas flow sputtering. This technique combines a hollow cathode glow discharge with an argon gas flow that supports transportation of sputtered material to the substrate. The mixture of gas and sputtered material flows

Stanley Tang; Uwe Schulz

2009-01-01

314

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 hydrates;…

Davis, Craig M.; Curran, Kelly A.

2007-01-01

315

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

316

Biochemical properties and mechanism of action of a vanadyl(IV)-aspirin complex on bone cell lines in culture.  

PubMed

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 (VOAspi) was evaluated on two osteoblast-like cell lines in culture, being its cytotoxic effects stronger than the vanadyl cation as assessed by morphological changes and lipid peroxidation. These effects may be partially explained through the induction of the expression of Erks (Extracellular signal-regulated kinases) and the inhibition of the PTPases (Phosphotyrosine phosphatases) present in the cellular extracts. PMID:11865824

Etcheverry, Susana B; Williams, Patricia A M; Sálice, Viviana C; Barrio, Daniel A; Ferrer, Evelina G; Cortizo, Ana M

2002-03-01

317

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

318

Low-complexity soft demodulation of MIMO-BICM using the line-search detector  

Microsoft Academic Search

Bit-interleaved coded modulation (BICM) is an attractive transmission scheme for MIMO wireless communications over fast fading channels. BICM receivers employing maximum-likelihood decoding require a soft demodulator (demapper) that calculates log-likelihood ratios (LLRs) for the coded bits. Because in the MIMO case the calculation of LLRs tends to he excessively complex, there is a strong demand for efficient soft demodulation algorithms

Dominik Seethaler; Gerald Matz; Franz Hlawatsch

2005-01-01

319

Antileukemic Efficacy of Monomeric Manganese-Based Metal Complex on KG-1A and K562 Cell Lines  

PubMed Central

Transitional metals and metal compounds have been used in versatile platforms for biomedical applications and therapeutic intervention. Severe side effects of anticancer drugs produce an urgent urge to develop new classes of anticancer agents with great potency as well as selectivity. In this background, recent studies demonstrate that monomeric manganese (MnII) thiocyanate complex (MMTC) holds great promise to exert effective antileukemic effects. MMTC was developed by a simple chemical reaction and characterized by elemental analyses, thermal analyses, and Fourier transform infrared (FTIR) spectroscopy. Anti-leukemic efficacy of the developed MMTC was estimated in KG-1A (AML) and K562 (CML) cell lines. Cell viability study, drug uptake assay, cellular redox balance (GSH and GSSG level), nitric oxide (NO) release level, reactive oxygen species (ROS) formation, alteration of mitochondrial membrane potential (MMP), and DNA fragmentation revealed that MMTC was able to produce significant antiproliferative effects on both cell lines at 25??g?mL?1 without showing any toxicological impact on normal lymphocytes. These findings will enlighten the biomedical application of manganese-based metal complexes as anti-leukemic agents.

Dash, Sandeep Kumar; Chattopadhyay, Sourav; Ghosh, Totan; Tripathy, Satyajit; Das, Sabyasachi; Das, Debasis; Roy, Somenath

2013-01-01

320

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

321

Lz-0 × Berkeley: a new Arabidopsis recombinant inbred line population for the mapping of complex traits.  

PubMed

This study describes the generation and test of a genetic resource suited to identify determinants of cell biological traits in plants. The use of quantitative trait loci (QTL) mapping for a better genetic understanding of cell biological traits is still at an early stage, even for biotechnologically important cell properties, such as the dimensions of fiber cells. A common strategy, the mapping of QTLs in recombinant inbred line (RIL) populations, is limited by the fact that the existing RIL populations exploit only a small fraction of the existing natural variation. Here, we report the mapping of QTLs impacting on the length of fiber cells in Arabidopsis inflorescence stems in a newly generated RIL population derived from a cross between the accessions Berkeley and the little known Lz-0. Through inbreeding of individual F2 plants, a total of 159 new F8 lines were produced and genotyped with a set of 49 single nucleotide polymorphism markers. The population was successfully used not only for the mapping of three QTLs controlling fiber length, but also to map five QTL controlling flowering time under short and long-day conditions. Our study demonstrates the usefulness of this new genetic resource by mapping in it QTLs underlying a poorly explored cellular trait as well as an already better explored regulatory pathway. The new RIL population and an online platform for the continuous supplementation of genetic markers will be generally available to substantially broaden the genetic diversity through which loci with impact on plant quantitative traits can be identified. PMID:24532030

Capron, Arnaud; Chang, Xue Feng; Shi, Chun; Beatson, Rodger; Berleth, Thomas

2014-06-01

322

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

323

Evolution of Mhc Class i Complex Region with Special Reference to Fragmentary Line Sequences  

NASA Astrophysics Data System (ADS)

We reviewed the origin and evolution of the two pairs of immune genes, (MHC-B and MHC-C) and (MICA and MICB) in man, chimpanzee and rhesus monkey based mainly on our previous work. Since those genes were well known to have been subject to strong natural selection in evolution, they themselves were not suitable for our study. We thus took another approach to use fragmented and nonfunctional LINEs that had coevolved with the two pairs in the same genomic fragments. Our results showed that MHC-B and MHC-C duplicated about 22 Mry (million years) ago, and MICA and MICB duplicated about 14 Myr ago. Interestingly, rhesus monkey was found not to have either pair but many repeats similar to MHC-B. Therefore, we estimated the divergence time of the monkey, and found that it diverged out from a common ancestor of man and chimpanzee about 30 Myr ago. The divergence time was consistent with the duplication times of the two pairs of immune genes. Based on our results we would predict that orangutan and gorilla also have the two pairs, because the both primate species are considered to have diverged less than 14 Myr ago.

Tateno, Yoshio; Fukami-Kobayashi, Kaoru; Inoko, Hidetoshi

2008-03-01

324

Polycomb repressor complex 2 regulates HOXA9 and HOXA10, activating ID2 in NK/T-cell lines  

PubMed Central

Background NK- and T-cells are closely related lymphocytes, originating from the same early progenitor cells during hematopoiesis. In these differentiation processes deregulation of developmental genes may contribute to leukemogenesis. Here, we compared expression profiles of NK- and T-cell lines for identification of aberrantly expressed genes in T-cell acute lymphoblastic leukemia (T-ALL) which physiologically regulate the differentiation program of the NK-cell lineage. Results This analysis showed high expression levels of HOXA9, HOXA10 and ID2 in NK-cell lines in addition to T-cell line LOUCY, suggesting leukemic deregulation therein. Overexpression experiments, chromatin immuno-precipitation and promoter analysis demonstrated that HOXA9 and HOXA10 directly activated expression of ID2. Concomitantly elevated expression levels of HOXA9 and HOXA10 together with ID2 in cell lines containing MLL translocations confirmed this form of regulation in both ALL and acute myeloid leukemia. Overexpression of HOXA9, HOXA10 or ID2 resulted in repressed expression of apoptosis factor BIM. Furthermore, profiling data of genes coding for chromatin regulators of homeobox genes, including components of polycomb repressor complex 2 (PRC2), indicated lacking expression of EZH2 in LOUCY and exclusive expression of HOP in NK-cell lines. Subsequent treatment of T-cell lines JURKAT and LOUCY with DZNep, an inhibitor of EZH2/PRC2, resulted in elevated and unchanged HOXA9/10 expression levels, respectively. Moreover, siRNA-mediated knockdown of EZH2 in JURKAT enhanced HOXA10 expression, confirming HOXA10-repression by EZH2. Additionally, profiling data and overexpression analysis indicated that reduced expression of E2F cofactor TFDP1 contributed to the lack of EZH2 in LOUCY. Forced expression of HOP in JURKAT cells resulted in reduced HOXA10 and ID2 expression levels, suggesting enhancement of PRC2 repression. Conclusions Our results show that major differentiation factors of the NK-cell lineage, including HOXA9, HOXA10 and ID2, were (de)regulated via PRC2 which therefore contributes to T-cell leukemogenesis.

2010-01-01

325

Genome-wide Introgression Lines and their Use in Genetic and Molecular Dissection of Complex Phenotypes in Rice ( Oryza sativa L.)  

Microsoft Academic Search

Tremendous efforts have been taken worldwide to develop genome-wide genetic stocks for rice functional genomic (FG) research since the rice genome was completely sequenced. To facilitate FG research of complex polygenic phenotypes in rice, we report the development of over 20 000 introgression lines (ILs) in three elite rice genetic backgrounds for a wide range of complex traits, including resistances\\/tolerances

Zhi-Kang Li; Bin-Ying Fu; Yong-Ming Gao; Jian-Long Xu; J. Ali; H. R. Lafitte; Yun-Zhu Jiang; J. Domingo Rey; C. H. M. Vijayakumar; R. Maghirang; Tian-Qing Zheng; Ling-Hua Zhu

2005-01-01

326

Evaluation of the Sensititre MycoTB Plate for Susceptibility Testing of the Mycobacterium tuberculosis Complex against First- and Second-Line Agents  

PubMed Central

The Sensititre MycoTB plate (TREK Diagnostic Systems, Cleveland, OH) uses a microtiter plate MIC format for susceptibility testing of Mycobacterium tuberculosis complex isolates against first- and second-line antituberculosis agents. Categorical agreement versus the agar proportion method for 122 M. tuberculosis complex isolates was 94% to 100%.

Hall, Leslie; Jude, Kurt P.; Clark, Shirley L.; Dionne, Kim; Merson, Ryan; Boyer, Ana; Parrish, Nicole M.

2012-01-01

327

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

328

Juvenile hormone analogs do not affect directly the activity of the ecdysteroid receptor complex in insect culture cell lines.  

PubMed

During insect development, ecdysteroids and juvenile hormones (JHs) interact to regulate larval growth, metamorphosis and reproduction but the molecular mechanisms by which both hormones influence each other's activity remain unknown. Because of their ease of use and straightforward genetic manipulation, insect cell lines often have been used to clarify the actions and interactions of hormones at the molecular level. Here we report on the use of two insect culture cell lines, Drosophila melanogaster S2 and Bombyx mori Bm5 cells, to investigate two molecular processes in which ecdysteroids and JH have been shown to interact: (1) direct modulation of the activity of the ecdysteroid receptor transcription complex and (2) interference at the level of induction of the primary gene E75. Our data do not support JH analogs (JHAs) acting through the above processes: 'antagonism' of ecdysteroid receptor activity by JHAs correlated with cytotoxicity and induction of E75 expression by JHAs was not demonstrated. However, we confirm previous studies in which it was observed that methoprene can partially reverse the growth inhibition by 20E in S2 cells (but not Bm5 cells). Therefore, the molecular mechanism by which both hormones influence each other's activity to regulate cell growth in S2 cells remains unknown. PMID:18093613

Soin, Thomas; Swevers, Luc; Mosallanejad, Hadi; Efrose, Rodica; Labropoulou, Vassiliki; Iatrou, Kostas; Smagghe, Guy

2008-02-01

329

Investigation of transport of genistein, daidzein and their inclusion complexes prepared with different cyclodextrins on Caco-2 cell line.  

PubMed

Isoflavonoids are widespread constituents in medical plants especially in legumes (Fabaceae), but occur in other different plant families as well (Rosaceae, Iridaceae, Amaranthaceae). Their antioxidant, estrogen-like, anti-inflammatory and analgesic effects make them promising compounds in therapy of important disorders especially in estrogen related diseases. Poor solubility in aqueous system of genistein and daidzein needs a solubility enhancement for pharmaceutical use. These compounds are suitable guest molecules for inclusion complex formation with cyclodextrins (CDs) considering matching their size and polarity. The molecular encapsulation with beta-cyclodextrin (?-CD), gamma-cyclodextrin (?-CD), hydroxypropyl-beta-cyclodextrin (HP-?-CD) and random methyl-beta cyclodextrin (RAMEB-CD) results in a solid, molecularly dispersed form and in a significantly improved aqueous solubility of genistein and daidzein. Determining enhancement in solubility and bioavailability we investigated the transport of these inclusion complexes across Caco-2 cell line comparing that of the pure compounds and found significant improving effect of the different CD derivatives on membrane permeation of the two isoflavone aglycons. PMID:23810850

Daruházi, Agnes Emma; Kiss, Tímea; Vecsernyés, Miklós; Szente, Lajos; Sz?ke, Eva; Lemberkovics, Eva

2013-10-01

330

A new low-complexity angular spread estimator in the presence of line-of-sight with angular distribution selection  

NASA Astrophysics Data System (ADS)

This article treats the problem of angular spread (AS) estimation at a base station of a macro-cellular system when a line-of-sight (LOS) is potentially present. The new low-complexity AS estimator first estimates the LOS component with a moment-based K-factor estimator. Then, it uses a look-up table (LUT) approach to estimate the mean angle of arrival (AoA) and AS. Provided that the antenna geometry allows it, the new algorithm can also benefit from a new procedure that selects the angular distribution of the received signal from a set of possible candidates. For this purpose, a nonlinear antenna configuration is required. When the angular distribution is known, any antenna structure could be used a priori; hence, we opt in this case for the simple uniform linear array (ULA). We also compare the new estimator with other low-complexity estimators, first with Spread Root-MUSIC, after we extend its applicability to nonlinear antenna array structures, then, with a recently proposed two-stage algorithm. The new AS estimator is shown, via simulations, to exhibit lower estimation error for the mean AoA and AS estimation.

Bousnina, Inès; Stéphenne, Alex; Affes, Sofiène; Samet, Abdelaziz

2011-12-01

331

Transport dynamics of broad resonances  

NASA Astrophysics Data System (ADS)

The propagation of short life time particles with consequently broad mass width are discussed in the context of transport descriptions. In the first part some known properties of finite life time particles such as resonances are reviewed and discussed at the example of the ?-meson. Grave deficiencies in some of the transport treatment of broad resonances are disclosed and quantified. The second part addresses the derivation of transport equations which permit to account for the damping width of the particles. Baym's ?-derivable method is used to derive a self-consistent and conserving scheme, which fulfils detailed balance relations even in the case of particles with broad mass distributions. For this scheme a conserved energy-momentum tensor can be constructed. Furthermore, a kinetic entropy can be derived which besides the standard quasi-particle part also includes contributions from fluctuations.

Knoll, J.

1999-04-01

332

HST/COS Observations of Galactic High-velocity Clouds: Four Active Galactic Nucleus Sight Lines through Complex C  

NASA Astrophysics Data System (ADS)

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 Å) and G160M (1383-1796 Å) 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_{H I} = 19.39-20.05 and log N_{O VI} = 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) ? 0.3-0.5, N(Si IV)/N(O VI) ? 0.05-0.11, N(N V)/N(O VI) ? 0.07-0.13, and N(Si IV)/N(Si III) ?0.2. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

Shull, J. Michael; Stevans, Matthew; Danforth, Charles; Penton, Steven V.; Lockman, Felix J.; Arav, Nahum

2011-10-01

333

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

334

AGS Broad Band Neutrino Beam.  

National Technical Information Service (NTIS)

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 w...

D. H. White

1985-01-01

335

Access to Complex Abortion Care Service and Planning Improved through a Toll-Free Telephone Resource Line.  

PubMed

Background. Providing equitable access to the full range of reproductive health services over wide geographic areas presents significant challenges to any health system. We present a review of a service provision model which has provided improved access to abortion care; support for complex issues experienced by women seeking nonjudgmental family planning health services; and a mechanism to collect information on access barriers. The toll-free pregnancy options service (POS) of British Columbia Women's Hospital and Health Centre sought to improve access to services and overcome barriers experienced by women seeking abortion. Methods. We describe the development and implementation of a province-wide toll-free telephone counseling and access facilitation service, including establishment of a provincial network of local abortion service providers in the Canadian province of British Columbia from 1998 to 2010. Results. Over 2000 women annually access service via the POS line, networks of care providers are established and linked to central support, and central program planners receive timely information on new service gaps and access barriers. Conclusion. This novel service has been successful in addressing inequities and access barriers identified as priorities before service establishment. The service provided unanticipated benefits to health care planning and monitoring of provincial health care related service delivery and gaps. This model for low cost health service delivery may realize similar benefits when applied to other health care systems where access and referral barriers exist. PMID:24693291

Norman, Wendy V; Hestrin, Barbara; Dueck, Royce

2014-01-01

336

Breaking limitations of complex culture media: functional non-viral miRNA delivery into pharmaceutical production cell lines.  

PubMed

MicroRNAs (miRNAs) are promising targets for cell engineering through modulation of crucial cellular pathways. An effective introduction of miRNAs into the cell is a prerequisite to reliably study microRNA function. Previously, non-viral delivery of nucleic acids has been demonstrated to be cell type as well as culture medium dependent. Due to their importance for biopharmaceutical research and manufacturing, Chinese hamster ovary (CHO) and Cevec's Amniocyte Production (CAP) cells were used as host cell lines to investigate transfection reagents with respect to successful delivery of small non-coding RNAs (ncRNAs) and their ability to allow for biological activity of miRNAs and small interfering RNAs (siRNAs) within the cell. In the present study, we screened numerous transfection reagents for their suitability to successfully deliver miRNA mimics into CHO DG44 and CAP cells. Our investigation revealed that the determination of transfection efficiency for a given transfection reagent alone is not sufficient to draw conclusions about its ability to maintain the functionality of the miRNA. We could show that independent from high transfection rates observed for several reagents only one was suitable for efficient introduction of functional miRNA mimics into cells cultured in complex protein production media. We provide evidence for the functionality of transferred ncRNAs by demonstrating siRNA-mediated changes in protein levels and cellular phenotype as well as decreased twinfilin-1 (twf-1) transcript levels by its upstream miR-1 regulator. Furthermore, the process could be shown to be scalable which has important implications for biotechnological applications. PMID:23994267

Fischer, Simon; Wagner, Andreas; Kos, Aron; Aschrafi, Armaz; Handrick, René; Hannemann, Juergen; Otte, Kerstin

2013-12-01

337

The ryanodine receptor/junctional channel complex is regulated by growth factors in a myogenic cell line.  

PubMed

The ryanodine receptor/junctional channel complex (JCC) forms the calcium release channel and foot structures of the sarcoplasmic reticulum. The JCC and the dihydropyridine (DHP) receptor in the transverse tubule are two of the major components involved in excitation-contraction (E-C) coupling in skeletal muscle. The DHP receptor is believed to serve as the voltage sensor in E-C coupling. Both the JCC and DHP receptor, as well as many skeletal muscle-specific contractile protein genes, are expressed in the BC3H1 muscle cell line. In the present study, we find that during differentiation of BC3H1 cells, induced by mitogen withdrawal, induction of the JCC and DHP receptor mRNAs is temporally similar to that of the skeletal muscle contractile protein genes alpha-tropomyosin and alpha-actin. Our data suggest that there is coordinate regulation of both the contractile protein genes (which have been studied in detail previously) and the genes encoding the calcium channels involved in E-C coupling. Induction of both calcium channels is accompanied by profound changes in BC3H1 cell morphology including the development of many components of mature skeletal muscle cells, despite lack of myoblast fusion. Visualized by electron microscopy, the JCC appears as "foot structures" located in the dyad junction between the plasmalemma and the sarcoplasmic reticulum of the BC3H1 cells. Development of foot structures is concomitant with JCC mRNA expression. Expression of the JCC and DHP receptor mRNAs and formation of the foot structures are inhibited specifically by fibroblast growth factor. PMID:1649198

Marks, A R; Taubman, M B; Saito, A; Dai, Y; Fleischer, S

1991-07-01

338

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  

PubMed Central

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 can be rejected by the recipients, we have analyzed whether maGSCs and iPSCs can become targets for cytotoxic T lymphocytes (CTL) or whether they are protected, as previously proposed for embryonic stem cells (ESCs). Results We have observed that maGSCs can be maintained in prolonged culture with or without leukemia inhibitory factor and/or feeder cells and still retain the capacity to form teratomas in immunodeficient recipients. They were, however, rejected in immunocompetent allogeneic recipients, and the immune response controlled teratoma growth. We analyzed the susceptibility of three maGSC lines to CTL in comparison to ESCs, iPSCs, and F9 teratocarcinoma cells. Major histocompatibility complex (MHC) class I molecules were not detectable by flow cytometry on these stem cell lines, apart from low levels on one maGSC line (maGSC Stra8 SSC5). However, using a quantitative real time PCR analysis H2K and B2m transcripts were detected in all pluripotent stem cell lines. All pluripotent stem cell lines were killed in a peptide-dependent manner by activated CTLs derived from T cell receptor transgenic OT-I mice after pulsing of the targets with the SIINFEKL peptide. Conclusion Pluripotent stem cells, including maGSCs, ESCs, and iPSCs can become targets for CTLs, even if the expression level of MHC class I molecules is below the detection limit of flow cytometry. Thus they are not protected against CTL-mediated cytotoxicity. Therefore, pluripotent cells might be rejected after transplantation by this mechanism if specific antigens are presented and if specific activated CTLs are present. Our results show that the adaptive immune system has in principle the capacity to kill pluripotent and teratoma forming stem cells. This finding might help to develop new strategies to increase the safety of future transplantations of in vitro differentiated cells by exploiting a selective immune response against contaminating undifferentiated cells. Reviewers This article was reviewed by Bhagirath Singh, Etienne Joly and Lutz Walter.

Dressel, Ralf; Guan, Kaomei; Nolte, Jessica; Elsner, Leslie; Monecke, Sebastian; Nayernia, Karim; Hasenfuss, Gerd; Engel, Wolfgang

2009-01-01

339

Regenerative soot as a source of broad band VUV light  

Microsoft Academic Search

:   A mechanism is proposed for the emission of a broad band VUV light to be emitted from the regenerative sooting discharges\\u000a on the basis of unusually intense intercombination lines of C+(CII) and C++(CIII) that have been observed. Comparison of these high intensity intercombination lines with the allowed transitions of\\u000a the highly excited and ionized C constituents of the sooting

Shoaib Ahmad

2003-01-01

340

Embryonal rhabdomyosarcoma of the broad ligament  

PubMed Central

Broad ligament tumors are uncommon. Sarcomas rarely arise from the broad ligament, leiomyosarcomas being the most common. Rhabdomyosarcomas of the broad ligament are very rare. To the best of our knowledge, no case of an embryonal rhabdomyosarcoma of the broad ligament has been reported in literature.

Chandarana, Mihir N.; Raghu, Shankar; Bhagat, Monica; Qureshi, Sajid

2014-01-01

341

Dibutyltin(IV) complexes containing arylazobenzoate ligands: chemistry, in vitro cytotoxic effects on human tumor cell lines and mode of interaction with some enzymes.  

PubMed

Dibutyltin(IV) complexes of composition Bu?Sn(LH)?, where LH is a carboxylate residue derived from 2-[(E)-(5-tert-butyl-2-hydroxyphenyl)diazenyl]benzoate (L¹H) with water molecule (1), 4-[(E)-(5-tert-butyl-2-hydroxyphenyl)diazenyl]benzoate (L²H) (2) and 4-[(E)-(4-hydroxy-5-methylphenyl)diazenyl]benzoate (L³H) (3), were synthesized and characterized by spectroscopic (¹H, ¹³C and ¹¹?Sn NMR, IR, ¹¹?Sn Mössbauer) techniques. A full characterization was accomplished from the crystal structure of complex 1. The molecular structures and geometries of the complexes (1a i.e. 1 without water molecule and 3) were fully optimized using the quantum mechanical method (PM6). Complexes 1 and 3 were found to exhibit stronger cytotoxic activity in vitro across a panel of human tumor cell lines viz., A498, EVSA-T, H226, IGROV, M19 MEL, MCF-7 and WIDR. Compound 3 is found to be four times superior for the A498, EVSA-T and MCF-7 cell lines than CCDP (cisplatin), and four, eight and sixteen times superior for the A498, H226 and MCF-7 cell lines, respectively, compared to ETO (etoposide). The mechanistic role of cytotoxic activity of test compounds is discussed in relation to the theoretical results of docking studies with some key enzymes such as ribonucleotide reductase, thymidylate synthase, thymidylate phosphorylase and topoisomerase II associated with the propagation of cancer. PMID:20012338

Basu Baul, Tushar S; Paul, Anup; Pellerito, Lorenzo; Scopelliti, Michelangelo; Singh, Palwinder; Verma, Pooja; Duthie, Andrew; de Vos, Dick; Tiekink, Edward R T

2011-04-01

342

The broad emission features in 'wake' in HD 153919  

NASA Technical Reports Server (NTRS)

It is shown that the broad emission features in the spectrum of HD 153919 are associated with the X-ray secondary and not significantly with the primary star. When the primary is at maximum velocity towards us, the HeI line lambda 4471 develops a blue shifted secondary component with a velocity of -470 km/sec relative to the primary.

Walker, E. N.

1976-01-01

343

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

344

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

2011-01-01

345

Power line-induced ac potential on natural gas pipelines for complex rights-of-way configurations. Volume 4. Field verification of horizontal wire mitigation method. Final report  

SciTech Connect

The joint use of common corridors for overhead electric power transmission lines and buried natural gas transmission pipelines is increasing. While many benefits accrue from the sharing of corridors, the coupling of electromagnetic energy onto the natural gas transmission pipelines is an undesired consequence of this joint usage. The steady-state pipeline voltage that can result may require mitigation as a safety measure. Many common corridors include multiple power lines and pipelines with complexities such as bonds or crossovers between the pipelines and terminating pipelines or insulators. This project has resulted in the development of the methodology and techniques for analyzing such complex common corridor coupling problems. Field tests were conducted to verify key aspects of the analysis.

Frazier, M.

1984-04-01

346

Synthesis, Characterization, and In Vitro Cytotoxic Activities of Benzaldehyde Thiosemicarbazone Derivatives and Their Palladium (II) and Platinum (II) Complexes against Various Human Tumor Cell Lines  

PubMed Central

The palladium (II) bis-chelate Pd (L1?3)2 and platinum (II) tetranuclear Pt4(L4)4 complexes of benzaldehyde thiosemicarbazone derivatives have been synthesized, and characterized by elemental analysis and IR, FAB(+)-mass and NMR (1H, 13C) spectroscopy. The complex Pd(L2)2 [HL2 = m-CN-benzaldehyde thiosemicarbazone] shows a square-planar geometry with two deprotonated ligands (L) coordinated to PdII through the nitrogen and sulphur atoms in a transarrangement, while the complex Pt4(L4)4 [HL4 = 4-phenyl-1-benzaldehyde thiosemicarbazone] has a tetranuclear geometry with four tridentate ligands coordinated to four PtII ions through the carbon (aromatic ring), nitrogen, and sulphur atoms where the ligands are deprotonated at the NH group. The in vitro antitumor activity of the ligands and their complexes was determined against different human tumor cell lines, which revealed that the palladium (II) and platinum (II) complexes are more cytotoxic than their ligands with IC50 values at the range of 0.07–3.67 ?M. The tetranuclear complex Pt4(L4)4, with the phenyl group in the terminal amine of the ligand, showed higher antiproliferative activity (CI50 = 0.07–0.12 ?M) than the other tested palladium (II) complexes.

Hernandeza, Wilfredo; Paz, Juan; Vaisberg, Abraham; Spodine, Evgenia; Richter, Rainer; Beyer, Lothar

2008-01-01

347

Broad interband semiconductor laser diodes  

NASA Astrophysics Data System (ADS)

A semiconductor laser is a diode device that emits light via stimulated emission. Conventionally, light emitted from a semiconductor laser is spatially coherent or narrowband. The fundamental mechanism of stimulated emission process in general leads only to a single wavelength emission. However, there are some lasers emit light with a broad spectrum or different distinct wavelength subjected to various operating conditions such as external grating configuration with semiconductor laser, diode-pumped self-Q-switch fiber laser, ultrashort pulse excitation, photonic crystal fiber, ultrabroadband solid-state lasers, semiconductor optical amplifier-based multiwavelength tunable fiber lasers, nonlinear crystal, broadband semiconductor laser etc. This type of broadband laser is vital in many practical applications such as optical telecommunications, spectroscopy measurement, imaging technology, etc. Recently, an ultra-broadband semiconductor laser that utilizes intersubband optical transitions via quantum cascade configuration has been realized. Laser action with a Fabry-Perot spectrum covering all wavelengths from 6 to 8 microm simultaneously is demonstrated with this approach. More recently, broadband emission results from interband optical transitions via quantum-dot/dash nanostructures have been demonstrated in a simple p-i-n laser diode structure. To date, this latest approach offers the simplest design by proper engineering of quantized energy states as well as utilizing the high inhomogeneity of the dot/dash nanostructures, which is inherent from self-assembled growth technology. In this dissertation, modeling of semiconductor InGaAs/GaAs quantum-dot broadband laser utilizing the properties of inhomogeneous and homogeneous broadening effects on lasing spectral will be discussed, followed by a detail analysis of another type of broad interband semiconductor laser, which is InAs/InGaAlAs quantum-dash broadband laser. Based on the device characterization results, broad interband laser emission is found to be originated from multiple families of quantum-dash ensembles in addition to multiple orders of subband energy levels within a single quantum-dash ensemble. Therefore, a novel technique is proposed and implemented successfully to enhance the lasing bandwidth of the quantum-dash broadband laser at postgrowth condition. Moreover, the design, growth and measurements of quantum-dash partial laser structures utilizing different epitaxial parameters are initiated to study the origins of unique lasing mechanism in broadband quantum-dash lasers. The measurement results support the postulation of the presence of multiple families of quantum-dash ensembles with different sizes across multiple stacking layers of quantum-dash/quantum-well/barrier and depict the importance of barrier width in controlling the stimulated emission bandwidth. These results lead to an important approach for future development to realize a single semiconductor laser diode that emits light in broad and continuous spectrum profile over more than 150 nm bandwidth.

Tan, Chee Loon

348

Analysis of a complex polysaccharide (gum arabic) by multi-angle laser light scattering coupled on-line to size exclusion chromatography and flow field flow fractionation  

Microsoft Academic Search

The heterogeneous polysaccharide gum arabic has been characterized using size exclusion chromatography (SEC) and flow field flow fractionation (F4) coupled on-line to multi-angle laser light scattering (MALLS). Two distinct populations have been shown. About 80% of the material consist of highly branched arabinogalactan (AG) units. The rest is mainly composed of heterogeneous arabinogalactan–protein complex (AGP) of high molecular weight. The

L. Picton; I. Bataille; G. Muller

2000-01-01

349

Subcellular Localization, Stability, and trans-Cleavage Competence of the Hepatitis C Virus NS3NS4A Complex Expressed in Tetracycline-Regulated Cell Lines  

Microsoft Academic Search

A tetracycline-regulated gene expression system and a panel of novel monoclonal antibodies were used to examine the subcellular localization, stability, and trans-cleavage competence of the hepatitis C virus (HCV) NS3-NS4A complex in inducible cell lines. The NS3 serine protease domain and the full-length NS3 protein ex- pressed in the absence of the NS4A cofactor were diffusely distributed in the cytoplasm

BENNO WOLK; DOMENICO SANSONNO; HANS-GEORG KRAUSSLICH; FRANCO DAMMACCO; CHARLES M. RICE; HUBERT E. BLUM; DARIUS MORADPOUR

2000-01-01

350

New developments in the theory of pressure-broadening and pressure-shifting of spectral lines of H 2O: The complex Robert-Bonamy formalism  

Microsoft Academic Search

Calculations of the halfwidth and line shift of water vapor perturbed by N2, O2, CO2, and H2 based on a complex implementation of the formalism of Robert and Bonamy are made. The potentials employ the leading terms of the electrostatic potential, a Lennard -Jones (6–12) atom-atom potential, and the induction and dispersion components of the isotropic potential. The dynamics of

Robert R. Gamache; Richard Lynch; Steven P. Neshyba

1998-01-01

351

Complexity of expression of the intermediate filaments of six new human ovarian carcinoma cell lines: new expression of cytokeratin 20.  

PubMed Central

Six permanent human ovarian carcinoma cell lines (OVISE, OVTOKO, OVMANA and OVSAYO from clear cell adenocarcinoma, and OVSAHO and OVKATE from serous papillary adenocarcinoma) were established from solid tumours. The cell lines have been in culture for 5-8 years, the passage number varying from 62 to 246. Immunohistochemical analysis has shown that five of the six cell lines express at least six cytokeratin (CK) polypeptides. OVISE and OVSAYO expressed CKs 6, 7, 8, 18, 19 and 15 and/or 16. OVTOKO was positive for CKs 7, 8, 18, 19 and 15 and/or 16. OVSAHO expressed CKs 6, 7, 8, 14, 18, 19 and 15 and/or 16. OVMANA expressed CKs 6, 7, 8, 18, 19, 20 and 15 and/or 16. OVKATE expressed CKs 6, 7, 8, 13, 17, 18, 19, 20 and 15 and/or 16. The expression of CK7, additional expression of vimentin, and clinical and histopathological findings enabled us to confirm that six cell lines had been established from primary ovarian cancers. Two of the six cell lines were positive for CK20, although CK20 was not expressed in the original tumours. The heterotransplanted tumours produced by CK20-positive cells also expressed CK20. This is the first report of ovarian carcinoma cell lines that express CK20 irrespective of their histological type. CK20 has been found in all colon carcinoma cell lines, but only in the mucinous type of ovarian tumours. These new ovarian carcinoma cell lines will therefore provide a relevant experimental system for elucidating the regulatory control mechanisms of intermediate filament expression. Images Figure 1 Figure 2 Figure 3

Yanagibashi, T.; Gorai, I.; Nakazawa, T.; Miyagi, E.; Hirahara, F.; Kitamura, H.; Minaguchi, H.

1997-01-01

352

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

353

Mapping and expression pattern analysis of key components of the major histocompatibility complex class I antigen processing and presentation pathway in a representative human renal cell carcinoma cell line.  

PubMed

Renal cell carcinoma (RCC) represent approximately 5% of all cancer deaths. At the time of presentation, over 50% of the patients have already developed locally advanced or metastatic disease with five-year survival rates of less than 20%. Although relative resistant to conventional regimens, RCC are partially susceptible to T cell-based immunotherapy. To further develop this treatment modality, two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) was applied for both the mapping of the key components of the major histocompatibility complex (MHC) class I antigen processing and presentation machinery (APM) and the characterization of the constitutive and cytokine-regulated protein expression profiles in a representative human RCC cell line. The latter aspect is based on the fact, that the expression level of some of the APM components can be altered in response to interferon (IFN)-gamma treatment. Total cell lysates from untreated and IFN-gamma-treated tumor cells were separated on 2-D PAGE gels using broad range immobilized pH gradient (IPG) strips. Serial Western blot analyses using sets of APM-specific antibodies were performed to target the relevant protein spots. Protein verification was mostly accomplished via peptide mass finger-printing using matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). To date, the majority of the APM-related components have been identified and mapped. In addition, the different protein expression profiles of untreated and IFN-gamma-treated RCC cells are under investigation. PMID:11425235

Lichtenfels, R; Ackermann, A; Kellner, R; Seliger, B

2001-05-01

354

Uniformly-Sensitive Line Hydrophones.  

National Technical Information Service (NTIS)

A uniformly-sensitive line hydrophone under development at the Woods Hole Oceanographic Institution has been used to receive broadband seismic reflection signals. The directivity characteristics of an adequately-long continuous line sensor used in a broad...

S. T. Knott F. R. Hess R. T. Nowak

1969-01-01

355

The 2006 Broad Prize for Urban Education  

ERIC Educational Resources Information Center

The $1 million Broad Prize in Urban Education is the nation's largest award in K-12 public education. The Broad Prize is given annually by The Broad Foundation in the form of scholarships to urban school districts that demonstrate the greatest overall performance and improvement in student achievement while reducing achievement gaps among ethnic…

Broad Foundation, 2006

2006-01-01

356

The synthesis and characterization of a series of cobalt(II) ?-ketoaminato complexes and their cytotoxic activity towards human tumor cell lines.  

PubMed

A series of square planar cobalt(II) compounds bearing tetradentate ?-ketoaminato ligands with variation in the number of -CF(3) ligand substituents has been prepared and structurally and spectroscopically characterized. The fluorinated ?-ketoamine ligands were prepared utilizing a multistep reaction sequence employing a silylenol protecting group. An additional tetrahedral cobalt compound bearing two bidentate ?-ketoaminato ligands was also prepared and characterized. Cytotoxic activity of the cobalt-containing complexes was evaluated using six human cell lines; including two different prostate cancer cell lines (PC-3 and VCaP), acute monocytic leukemia (THP-1), astrocytoma (U-373 MG), hepatocellular carcinoma (HepG2), and neuroblastoma (SH-SY5Y) cells. The cobalt compounds are more active than their corresponding ligands. The activity is cell type specific; the cobalt compounds exhibit strong activity against human prostate cancer and monocytic leukemia cells but weak or no activity against neuroblastoma, astrocytoma, and liver carcinoma cells. Activity generally increases with a greater number of -CF(3) substituents, and square planar complexes exhibit greater activity than the tetrahedral derivative. The mechanisms of activity against human PC-3 prostate cancer cells involve caspase-3 and two different mitogen-activated protein kinases. The addition of a thiol antioxidant reduced cytotoxicity, suggesting the possible involvement of reactive oxygen species. These cobalt complexes may represent a novel class of cytotoxic drugs selective towards certain types of tumors. PMID:21501578

Gurley, Lydia; Beloukhina, Natalia; Boudreau, Kalun; Klegeris, Andis; McNeil, W Stephen

2011-06-01

357

On the detection of environmental effects on complex matrices combining off-line liquid chromatography and 1H-NMR  

Microsoft Academic Search

An off-line combination of 400 MHz proton (1H)-NMR spectroscopy and liquid chromatography (LC) has been used for the multi-component comparison of low-molecular weight compounds (i.e., chemical fingerprinting) in model fluid broths and (processed) tomato. The focus of the research described is on (i) devising GLP-like methods for sample handling and NMR measurements that will ensure reproducibility, (ii) an automated handling

Arjen Lommen; Joop M. Weseman; Geo O. Smith; Hub P. J. M. Noteborn

1998-01-01

358

A recursive node imbalance method incorporating a model of flowrate dynamics for on-line material balance of complex flowsheets  

Microsoft Academic Search

A method is proposed to perform on-line material balance of mineral processing circuits using on-stream assays and flowrate measurements. The method, based on a least-squares recursive procedure, is derived from the node imbalance method developed for steady-state mass balance, and incorporates additional equations to represent the dynamic evolution of the flowrates. The method is illustrated for a simulated separation unit

S. Makni; D. Hodouin; C. Bazin

1995-01-01

359

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

NASA Astrophysics Data System (ADS)

Complex decay scheme construction using beta decay of isotopes produced by spallation and mass separation on-line at TRIUMF-ISAC and studied with the 8? 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 ?-ray lines to isobars, and the use of conversion electron coincidences to observe low-energy transitions. The goal of this work is to achieve detailed decay scheme spectroscopy far from stability with the same level of detail as obtained with the 8? array near stabilty in earlier N=90 studies [1] [2]. [1] W.D. Kulp et al., Phys. Rev. C 69, 064309 (2004). [2] W.D. Kulp et al., Phys. Rev. C 76, 034319 (2007).

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

2008-10-01

360

Treatment of ovarian cancer cell lines with 5-aza-2?-deoxycytidine upregulates the expression of cancer-testis antigens and class I major histocompatibility complex-encoded molecules  

Microsoft Academic Search

Purpose  To test the hypothesis that decrease in DNA methylation will increase the expression of cancer-testis antigens (CTA) and class\\u000a I major histocompatibility complex (MHC)-encoded molecules by ovarian cancer cells, and thus increase the ability of these\\u000a cells to be recognized by antigen-reactive CD8+ T cells.\\u000a \\u000a \\u000a \\u000a Methods  Human ovarian cancer cell lines were cultured in the presence or absence of varying concentrations

Sara J. Adair; Kevin T. Hogan

2009-01-01

361

Direct Detection of Mycobacterium tuberculosis Complex DNA and Rifampin Resistance in Clinical Specimens from Tuberculosis Patients by Line Probe Assay  

Microsoft Academic Search

The INNO-LiPA.Rif TB test (LiPA) has only been applied to a limited number of clinical specimens. To assess the utility of this test for detecting Mycobacterium tuberculosis complex DNA and rifampin (RMP) resistance, 420 sputum samples comprising specimens from untreated (n 160) and previously treated (n 260) patients from 11 countries in Asia, Africa, Europe, and Latin America were tested.

Hamidou Traore; Armand van Deun; Isdore Chola Shamputa; Leen Rigouts; Francoise Portaels

362

The Design of Broad-Band Aircraft-Antenna Systems  

Microsoft Academic Search

A complete technique for the development of broadband aircraft antennas at frequencies from 10 to 100 megacycles is described. The paper is divided into three sections concerned with (1) antenna-impedance measurement in aircraft, (2) design of reactance-matching sections for antenna, and (3) development of broad-band wire antennas for aircraft use. Part I. Impedance Measurement: A coiled line and probe assembly,

F. D. Bennett; P. D. Coleman; A. S. Meier

1945-01-01

363

The Nogo-C2/Nogo Receptor Complex Regulates the Morphogenesis of Zebrafish Lateral Line Primordium through Modulating the Expression of dkk1b, a Wnt Signal Inhibitor  

PubMed Central

The fish lateral line (LL) is a mechanosensory system closely related to the hearing system of higher vertebrates, and it is composed of several neuromasts located on the surface of the fish. These neuromasts can detect changes in external water flow, to assist fish in maintaining a stationary position in a stream. In the present study, we identified a novel function of Nogo/Nogo receptor signaling in the formation of zebrafish neuromasts. Nogo signaling in zebrafish, like that in mammals, involves three ligands and four receptors, as well as three co-receptors (TROY, p75, and LINGO-1). We first demonstrated that Nogo-C2, NgRH1a, p75, and TROY are able to form a Nogo-C2 complex, and that disintegration of this complex causes defective neuromast formation in zebrafish. Time-lapse recording of the CldnB::lynEGFP transgenic line revealed that functional obstruction of the Nogo-C2 complex causes disordered morphogenesis, and reduces rosette formation in the posterior LL (PLL) primordium during migration. Consistent with these findings, hair-cell progenitors were lost from the PLL primordium in p75, TROY, and Nogo-C2/NgRH1a morphants. Notably, the expression levels of pea3, a downstream marker of Fgf signaling, and dkk1b, a Wnt signaling inhibitor, were both decreased in p75, TROY, and Nogo-C2/NgRH1a morphants; moreover, dkk1b mRNA injection could rescue the defects in neuromast formation resulting from knockdown of p75 or TROY. We thus suggest that a novel Nogo-C2 complex, consisting of Nogo-C2, NgRH1a, p75, and TROY, regulates Fgf signaling and dkk1b expression, thereby ensuring stable organization of the PLL primordium.

Han, Hao-Wei; Chou, Chih-Ming; Chu, Cheng-Ying; Cheng, Chia-Hsiung; Yang, Chung-Hsiang; Hung, Chin-Chun; Hwang, Pung-Pung; Lee, Shyh-Jye; Liao, Yung-Feng; Huang, Chang-Jen

2014-01-01

364

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

365

Investigation on the pharmacological profile of antimony(III) complexes with hydroxyquinoline derivatives: anti-trypanosomal activity and cytotoxicity against human leukemia cell lines.  

PubMed

Complexes [Sb(QN)(2)Cl] (1), [Sb(QC)(2)Cl] (2) and [Sb(QI)(2)Cl] (3) were obtained with 8-hydroxyquinoline (HQN), 5-chloro-8-hydroxyquinoline (HQC) and 5-chloro-7-iodo-8-hydroxyquinoline (clioquinol, HQI). The quinoline derivatives and their antimony(III) complexes were evaluated for their anti-trypanosomal activity as well as for their cytotoxicity against HL-60 and Jurkat human leukemia cell lines. Upon coordination to antimony(III) the anti-trypanosomal activity of HQC and HQI increases, the highest improvement being observed for complex (3), which was the most active among all studied compounds against both epimastigote and trypomastigote forms of Trypanosoma cruzi. All quinoline derivatives proved to be cytotoxic against both leukemia cell lineages. Upon coordination to antimony(III) the cytotoxicity of HQN improved against Jurkat leukemia cells. While SbCl(3) proved to be cytotoxic against HL-60 cells, it was not active against Jurkat cells. However, its coordination to the quinoline derivatives resulted in complexes with significant cytotoxicity against Jurkat cells. PMID:21221718

Reis, Débora C; Pinto, Mauro C X; Souza-Fagundes, Elaine M; Rocha, Lucas F; Pereira, Valéria R A; Melo, Cristiane M L; Beraldo, Heloisa

2011-08-01

366

The H? Line Shape of Akn 120  

NASA Astrophysics Data System (ADS)

We present here the Akn 120 H? line profiles from 97 spectra observed from 1977 till 1990 at Crimean Astrophysical Observatory (Appendix 1). The H? line has been fitted with three broad and one narrow Gaussian throughout the whole considered period. The central broad components of the H? and a shelf cause the H? line shape variation. Three broad Gaussians may suggest the existence of three broad line regions in the central part of the Akn 120. Long-term H? line shape variations in spectra of this galaxy are discussed.

Stanic, N.; Popovic, L. C.; Kubicela, A.; Bon, E.