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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

Unveiling the X-ray broad band continuum and iron line complex on Mkn 841  

NASA Astrophysics Data System (ADS)

Mkn 841 has been observed during 3 different periods (January 2001, January 2005 and July 2005) by XMM-Newton for a total cumulated exposure time of 108 ks. We present in this paper a broad band spectral analysis of the complete EPIC-pn data sets. These observations confirm the presence of the strong soft excess and complex iron line profile known to be present in this source since a long time. They also reveal their extreme and puzzling spectral and temporal behaviors. Indeed, the 0.5-2 keV soft X-ray flux decreases by a factor 3 between 2001 and 2005 and the line shape appears to be a mixed of broad and narrow components, both variable but on different timescales. The broad-band 0.5-10 keV spectra are well described by a model including a primary power law continuum, a blurred photoionized reflection and a narrow iron line, the blurred reflection fitting self-consistently the soft excess and the broad line component. The origin and nature of the narrow component is unclear.

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

3

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

NASA Astrophysics Data System (ADS)

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

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

2007-08-01

4

Calcium channel blockers as first line treatment for broad complex tachycardia with right bundle branch block: ingenuity or folly?  

Microsoft Academic Search

Objective: To study the response of regular broad-complex tachycardia (BCT) demonstrating right bundle branch block (RBBB) to treatment in the Emergency department (ED). Methods: Retrospective chart review of management of patients with BCT, RBBB without a history of ischaemic heart disease. A diagnosis of ventricular tachycardia (VT) was made if the ECG showed features such as atrioventricular dissociation, capture or

Jenn Chyuan Wang; Swee Han Lim; Wee Siong Teo; V Anantharaman

2002-01-01

5

Relativistic redshifts in quasar broad lines  

E-print Network

The broad emission lines commonly seen in quasar spectra have velocity widths of a few per cent of the speed of light, so special- and general-relativistic effects have a significant influence on the line profile. We have determined the redshift of the broad H-beta line in the quasar rest frame (determined from the core component of the [OIII] line) for over 20,000 quasars from the Sloan Digital Sky Survey DR7 quasar catalog. The mean redshift as a function of line width is approximately consistent with the relativistic redshift that is expected if the line originates in a randomly oriented Keplerian disk that is obscured when the inclination of the disk to the line of sight exceeds ~30-45 degrees, consistent with simple AGN unification schemes. This result also implies that the net line-of-sight inflow/outflow velocities in the broad-line region are much less than the Keplerian velocity when averaged over a large sample of quasars with a given line width.

Tremaine, Scott; Liu, Xin; Loeb, Abraham

2014-01-01

6

Relativistic Redshifts in Quasar Broad Lines  

NASA Astrophysics Data System (ADS)

The broad emission lines commonly seen in quasar spectra have velocity widths of a few percent of the speed of light, so special- and general-relativistic effects have a significant influence on the line profile. We have determined the redshift of the broad H? line in the quasar rest frame (determined from the core component of the [O III] line) for over 20,000 quasars from the Sloan Digital Sky Survey Data Release 7 quasar catalog. The mean redshift as a function of line width is approximately consistent with the relativistic redshift that is expected if the line originates in a randomly oriented Keplerian disk that is obscured when the inclination of the disk to the line of sight exceeds ~30°-45°, consistent with simple active galactic nucleus unification schemes. This result also implies that the net line-of-sight inflow/outflow velocities in the broad-line region are much less than the Keplerian velocity when averaged over a large sample of quasars with a given line width.

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

2014-10-01

7

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

8

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

9

MICROLENSING OF QUASAR BROAD EMISSION LINES: CONSTRAINTS ON BROAD LINE REGION SIZE  

SciTech Connect

We measure the differential microlensing of the broad emission lines between 18 quasar image pairs in 16 gravitational lenses. We find that the broad emission lines are in general weakly microlensed. The results show, at a modest level of confidence (1.8{sigma}), that high ionization lines such as C IV are more strongly microlensed than low ionization lines such as H{beta}, indicating that the high ionization line emission regions are more compact. If we statistically model the distribution of microlensing magnifications, we obtain estimates for the broad line region size of r{sub s} = 24{sup +22} {sub -15} and r{sub s} = 55{sup +150} {sub -35} lt-day (90% confidence) for the high and low ionization lines, respectively. When the samples are divided into higher and lower luminosity quasars, we find that the line emission regions of more luminous quasars are larger, with a slope consistent with the expected scaling from photoionization models. Our estimates also agree well with the results from local reveberation mapping studies.

Guerras, E.; Mediavilla, E. [Instituto de Astrofisica de Canarias, Via Lactea S/N, La Laguna E-38200, Tenerife (Spain)] [Instituto de Astrofisica de Canarias, Via Lactea S/N, La Laguna E-38200, Tenerife (Spain); Jimenez-Vicente, J. [Departamento de Fisica Teorica y del Cosmos, Universidad de Granada, Campus de Fuentenueva, E-18071 Granada (Spain)] [Departamento de Fisica Teorica y del Cosmos, Universidad de Granada, Campus de Fuentenueva, E-18071 Granada (Spain); Kochanek, C. S. [Department of Astronomy and the Center for Cosmology and Astroparticle Physics, The Ohio State University, 4055 McPherson Lab, 140 West 18th Avenue, Columbus, OH 43221 (United States)] [Department of Astronomy and the Center for Cosmology and Astroparticle Physics, The Ohio State University, 4055 McPherson Lab, 140 West 18th Avenue, Columbus, OH 43221 (United States); Munoz, J. A. [Departamento de Astronomia y Astrofisica, Universidad de Valencia, E-46100 Burjassot, Valencia (Spain)] [Departamento de Astronomia y Astrofisica, Universidad de Valencia, E-46100 Burjassot, Valencia (Spain); Falco, E. [Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Motta, V. [Departamento de Fisica y Astronomia, Universidad de Valparaiso, Avda. Gran Bretana 1111, Valparaiso (Chile)] [Departamento de Fisica y Astronomia, Universidad de Valparaiso, Avda. Gran Bretana 1111, Valparaiso (Chile)

2013-02-20

10

Properties of quasar broad absorption line outflows  

NASA Astrophysics Data System (ADS)

Broad absorption lines (BALs) in quasar spectra identify high velocity outflows that likely exist in all quasars and could play a major role in feedback to galaxy evolution. In this dissertation, I use two methods to illuminate important properties of these outflows with the goal of a better understanding of these outflow systems and ultimately of the connection between quasars and their host galaxies. The variability of BALs can help us understand the structure, evolution, and basic physical properties of the outflows. I report here on a BAL monitoring programme of a sample of 24 luminous quasars at redshifts 1.2line variations, and (perhaps) for structural changes in the outflows, is less than a few years. The evidence presented here indicates that the cause of variability is likely a complex mixture of changing ionization in the outflowing gas and cloud movements across our lines-of-sight. Part of the BAL monitoring programme specifically focused on obtaining multiple observations at rest-frame time-scales <1 month in order to determine whether there is a minimum time-scale threshold below which there is no variability. The shortest variability time-scales help determine how close to the central SMBH this outflowing gas can be located. I detect variability down to a rest-frame time-scale of ˜0.02 yr (8--10 days), which constrains the location of the outflowing gas from the central super-massive black hole in these systems down to sub-parsec scales. Finally, in order to determine the viability of quasar outflows as a feedback mechanism affecting galaxy evolution, we need estimates of their mass outflow rates and kinetic energy yields. These quantities depend on the column densities of the flows, which are difficult to obtain directly from spectra of the BALs. We turn to a low-abundance species, P V lambda1118, 1128. Phosphorus is much less abundant than, for example, carbon (P/C ˜ 0.001 in the Sun), so a detection of a P V BAL indicates that other lines, such as C IV, are saturated. We detect variability in a P V BAL in Q1413+1143, corresponding to variable Si IV and C IV BALs. The variability in the P V BAL confirms that the absorption is intrinsic to the quasar and provides a constraint on the location of the gas. Using the apparent optical depth of the P V BAL and photoionization models to constrain the true column density of the outflow, we estimate the kinetic energy yields and compare to simulations to find that this outflow could likely be a viable feedback mechanism.

Capellupo, Daniel Moshin

11

Magnetohydrodynamic stability of broad line region clouds  

NASA Astrophysics Data System (ADS)

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

Krause, Martin; Schartmann, Marc; Burkert, Andreas

2012-10-01

12

Thickness effects with intrinsically broad absorption lines  

NASA Astrophysics Data System (ADS)

Thickness effects have been studied extensively, both numerically and analytically, only for the case where the intrinsic absorber cross-section, ?a, is an elemental Lorentzian line having the natural Heisenberg width. Thickness effects with ?a's corresponding to intrinsically (homogeneously or inhomogeneously) broadened lines have hardly not been studied. We report a numerical study of the latter case in which the ?a's are taken to be single Voigt lines of various Gaussian-width to Heisenberg-width ratios (O ? ?/?o ? 10). We obtain “phase diagrams” showing effectively thin-absorber regions in the plane of intrinsic broadening (?/?o or FWHM of ?a) versus total absorber thickness (O ? ta ? fana?o ? 10). These diagrams are useful in evaluating when and to what extent spectral distortions from thickness effects need to be taken into account in real situations.

Ping, J. Y.; Rancourt, D. G.

1992-04-01

13

A Search for Broad Infrared Recombination Lines in NGC 1068  

Microsoft Academic Search

We report infrared spectroscopy of the prototypical Seyfert 2 galaxy NGC 1068, aiming at detection of broad components of hydrogen recombination lines that originate in the obscured broad-line region. Using the Short Wavelength Spectrometer on board the Infrared Space Observatory, we have observed for the first time the regions of Bbeta 2.626 mum and Pfalpha 7.460 mum, and present improved

D. Lutz; R. Genzel; E. Sturm; L. Tacconi; E. Wieprecht; T. Alexander; H. Netzer; A. Sternberg; A. F. M. Moorwood; R. A. E. Fosbury; K. Fricke; S. J. Wagner; A. Quirrenbach; H. Awaki; K. Y. Lo

2000-01-01

14

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

15

Millihertz QPOs and broad iron line from LMC X-1  

E-print Network

We study the temporal and energy spectral characteristics of the persistent black hole X-ray binary LMC X-1 using two XMM-Newton and a Suzaku observation. We report the discovery of low frequency (~ 26-29 mHz) quasi-periodic oscillations (QPOs). We also report the variablity of the broad iron K-alpha line studied earlier with Suzaku. The QPOs are found to be weak with fractional rms amplitude in the ~ 1-2 % range and quality factor Q~2-10 . They are accompanied by weak red noise or zero-centered Lorentzian components with rms variability at the ~ 1-3 % level. The energy spectra consists of three varying components - multicolour disk blackbody (kT_{in} ~ 0.7-0.9 keV), high energy power-law tail (Gamma ~ 2.4 - 3.3) and a broad iron line at 6.4-6.9 keV. The broad iron line, the QPO and the strong power-law component are not always present. The QPOs and the broad iron line appear to be clearly detected in the presence of a strong power-law component. The broad iron line is found to be weaker when the disk is like...

Alam, Md Shah; Belloni, T; Mukherjee, D; Jhingan, S

2014-01-01

16

Seven broad absorption line quasars with excess broad band absorption near 2250  

E-print Network

We report the discovery of excess broad band absorption near 2250 A (EBBA) in the spectra of seven broad absorption line (BAL) quasars. By comparing with the statistical results from the control quasar sample, the significance for the detections are all above the > 4{\\sigma} level, with five above > 5{\\sigma}. The detections have also been verified by several other independent methods. The EBBAs present broader and weaker bumps at smaller wavenumbers than the Milky Way, and similar to the Large Magellanic Cloud. The EBBA bump may be related to the 2175 A bump seen in the Local Group and may be a counterpart of the 2175 A bump under different conditions in the early Universe. Furthermore, five objects in this sample show low-ionization broad absorption lines (LoBALs), such as Mg II and Al III, in addition to the high-ionization broad absorption lines (HiBALs) of C IV and Si IV. The fraction of LoBALs in our sample, ~70%, is surprisingly high compared to that of general BAL quasars, ~10%. Although the origin of...

Zhang, Shaohua; Jiang, Peng; Zhou, Hongyan; Ma, Jingzhe; Brandt, W N; York, Donald G; Noterdaeme, P; Schneider, Donald P

2014-01-01

17

Broad redshifted line as a signature of outflow  

E-print Network

We formulate and solve the diffusion problem of line photon propagation in a bulk outflow from a compact object (black hole or neutron star) using a generic assumption regarding the distribution of line photons within the outflow. Thomson scattering of the line photons within the expanding flow leads to a decrease of their energy which is of first order in v/c, where v is the outflow velocity and c is the speed of light. We demonstrate that the emergent line profile is closely related to the time distribution of photons diffusing through the flow (the light curve) and consists of a broad redshifted feature. We analyzed the line profiles for the general case of outflow density distribution. We emphasize that the redshifted lines are intrinsic properties of the powerful outflow that are supposed to be in many compact objects.

Titarchuk, L G; Becker, P A; Titarchuk, Lev; Kazanas, Demos; Becker, Peter A.

2003-01-01

18

Broad redshifted line as a signature of outflow  

E-print Network

We formulate and solve the diffusion problem of line photon propagation in a bulk outflow from a compact object (black hole or neutron star) using a generic assumption regarding the distribution of line photons within the outflow. Thomson scattering of the line photons within the expanding flow leads to a decrease of their energy which is of first order in v/c, where v is the outflow velocity and c is the speed of light. We demonstrate that the emergent line profile is closely related to the time distribution of photons diffusing through the flow (the light curve) and consists of a broad redshifted feature. We analyzed the line profiles for the general case of outflow density distribution. We emphasize that the redshifted lines are intrinsic properties of the powerful outflow that are supposed to be in many compact objects.

Lev Titarchuk; Demos Kazanas; Peter A. Becker

2003-07-28

19

The complex iron line of NGC 5506  

NASA Astrophysics Data System (ADS)

The bright Narrow Emission Line Galaxy, NGC 5506, has been observed simultaneously by XMM-Newton and BeppoSAX. The iron line is complex, with at least two components: one narrow and corresponding to neutral iron, the second one broad and corresponding to ionized iron. The latter line is equally well fitted by a truly broad line or by a blend of He- and H-like narrow lines. The bulk of the Compton reflection continuum originates in neutral matter, and is therefore associated with the narrow line: they are most likely emitted in distant matter. The origin of the ionized line(s) is less certain, but the solution in terms of a blend of narrow lines from photoionized matter seems to be preferable to emission from an ionized, relativistic accretion disc.

Matt, G.; Guainazzi, M.; Perola, G. C.; Fiore, F.; Nicastro, F.; Cappi, M.; Piro, L.

2001-10-01

20

Broad Absorption Line Quasar catalogues with Supervised Neural Networks  

SciTech Connect

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

Scaringi, Simone; Knigge, Christian [Department of Physics and Astronomy, University of Southampton, Highfield, SO17 1BJ (United Kingdom); Cottis, Christopher E.; Goad, Michael R. [Department of Physics and Astronomy, University of Leicester, University road, LE1 7RH (United Kingdom)

2008-12-05

21

Variability in Low Ionization Broad Absorption Line Outflows  

E-print Network

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 = 1 year) absorption line variability is seen in 8 cases (36% systems) while only 4 of them (i.e 18% systems) show variability over short time-scales (i.e 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...

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

2014-01-01

22

Broad Line Radio Galaxies with NuSTAR  

NASA Astrophysics Data System (ADS)

The formation of relativistic jets is an open question in AGN physics. Despite significant observational efforts it is still unclear why some AGN show strong radio jets while others do not. Of particular interest to answer this question are broad line radio galaxies, which do show a strong jet but otherwise show an X-ray spectrum similar to their radio-quiet kin. While studies of the standard X-ray band (0.5-10 keV) have not yielded any significant insights, the newly launched X-ray mission NuSTAR offers the possibility to also study the hard X-ray spectra of these sources. In combination with coordinated XMM-Newton and Suzaku observations this provides the best broad-band X-ray spectra of broad line radio galaxies to-date. In this talk I will discuss the first results from the NuSTAR Radio Galaxy program and their implications for our understanding of jet formation.

Lohfink, A.; Ogle, P.; Matt, G.; Lanz, L.; Madejski, G.; Reynolds, C.; Walton, D.; Harrison, F.

2014-07-01

23

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

24

SPECTROPOLARIMETRY OF RADIO-SELECTED BROAD ABSORPTION LINE QUASARS  

SciTech Connect

We report spectropolarimetry of 30 radio-selected broad absorption line (BAL) quasars with the Keck Observatory, 25 from the sample of Becker et al. Both high- and low-ionization BAL quasars are represented, with redshifts ranging from 0.5 to 2.5. The spectropolarimetric properties of radio-selected BAL quasars are very similar to those of radio-quiet BAL quasars: a sizeable fraction (20%) shows large continuum polarization (2%-10%) usually rising toward short wavelengths; emission lines are typically less polarized than the continuum; and absorption line troughs often show large polarization jumps. There are no significant correlations between polarization properties and radio properties, including those indicative of system orientation, suggesting that BAL quasars are not simply normal quasars seen from an edge-on perspective.

DiPompeo, M. A.; Brotherton, M. S. [Department of Physics and Astronomy, University of Wyoming, 3905, 1000 East University Avenue, Laramie, WY 82071 (United States); Becker, R. H.; Gregg, M. D. [Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, 7000 East Avenue, P.O. Box 808, L413, Livermore, CA 94550 (United States); Tran, H. D. [W. M. Keck Observatory, 65-1120 Mamalahoa Hwy, Kamuela, HI 96743 (United States); White, R. L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Laurent-Muehleisen, S. A. [Illinois Institute of Technology, 3101 South Dearborn St., Chicago, IL 60616 (United States)

2010-07-15

25

Radiation pressure confinement - IV. Application to broad absorption line outflows  

NASA Astrophysics Data System (ADS)

A fraction of quasars present broad absorption lines, produced by outflowing gas with typical velocities of 3000-10 000 km s-1. If the outflowing gas fills a significant fraction of the volume where it resides, then it will be highly ionized by the quasar due to its low density, and will not produce the observed UV absorption. The suggestion that the outflow is shielded from the ionizing radiation was excluded by recent observations. The remaining solution is a dense outflow with a filling factor f < 10-3. What produces such a small f? Here, we point out that radiation pressure confinement (RPC) inevitably leads to gas compression and the formation of dense thin gas sheets/filaments, with a large gradient in density and ionization along the line of sight. The total column of ionized dustless gas is a few times 1022 cm-2, consistent with the observed X-ray absorption and detectable P V absorption. The predicted maximal columns of various ions show a small dependence on the system parameters, and can be used to test the validity of RPC as a solution for the overionization problem. The ionization structure of the outflow implies that if the outflow is radiatively driven, then broad absorption line quasars should have L/L_Eddgtrsim 0.1.

Baskin, Alexei; Laor, Ari; Stern, Jonathan

2014-12-01

26

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

27

Shielding Gas Variations in Transforming Broad Absorption Line Quasars  

NASA Astrophysics Data System (ADS)

X-ray/EUV absorbing shielding gas is thought to be essential for the driving of Broad Absorption Line (BAL) quasar winds, but the nature of this key component requires further investigation. Using a large sample of multi-year BAL variability observations from SDSS-I/II/III, we have discovered a set of quasars that have fully transformed from being BAL quasars to non-BAL quasars; all BAL troughs have disappeared. A promising model for these transformations invokes variations of the shielding gas that increase the level of ionizing X-ray/EUV radiation reaching the BAL wind. We propose timely Chandra observations of 9 transforming BAL quasars to determine if their shielding gas has moved entirely out of our line-of-sight, leaving behind an X-ray unabsorbed non-BAL quasar.

Brandt, W. N.

2014-09-01

28

The sub-millimeter properties of broad absorption line quasars  

E-print Network

We have carried out the first systematic survey of the sub-millimeter properties of broad absorption line (BAL) quasars. 30 BAL quasars drawn from a homogeneously selected sample from the Sloan Digital Sky Survey at redshifts 2 2 sigma significance, four of which are at > 3 sigma significance. The far-infrared luminosities of these quasars are > 10^{13} L_solar. There is no correlation of sub-millimeter flux with either the strength of the broad absorption feature or with absolute magnitude in our sample. We compare the sub-millimeter flux distribution of the BAL quasar sample with that of a sample of quasars which do not show BAL features in their optical spectra and find that the two are indistinguishable. BAL quasars do not have higher sub-millimeter luminosities than non-BAL quasars. These findings are consistent with the hypothesis that all quasars would contain a BAL if viewed along a certain line-of-sight. The data are inconsistent with a model in which the BAL phenomenon indicates a special evolutionary stage which co-incides with a large dust mass in the host galaxy and a high sub-millimeter luminosity. Our work provides constraints on alternative evolutionary explanations of BAL quasars.

Chris J. Willott; Steve Rawlings; Jennifer A. Grimes

2003-08-11

29

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

30

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,; /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; Brinkmann, John; /Apache Point Observ.

2005-09-01

31

Microlensing of the broad line region in 17 lensed quasars  

NASA Astrophysics Data System (ADS)

When an image of a strongly lensed quasar is microlensed, the different components of its spectrum are expected to be differentially magnified owing to the different sizes of the corresponding emitting region. Chromatic changes are expected to be observed in the continuum while the emission lines should be deformed as a function of the size, geometry and kinematics of the regions from which they originate. Microlensing of the emission lines has been reported only in a handful of systems so far. In this paper we search for microlensing deformations of the optical spectra of pairs of images in 17 lensed quasars with bolometric luminosities between 1044.7 - 47.4 erg/s and black hole masses 107.6 - 9.8 M?. This sample is composed of 13 pairs of previously unpublished spectra and four pairs of spectra from literature. Our analysis is based on a simple spectral decomposition technique which allows us to isolate the microlensed fraction of the flux independently of a detailed modeling of the quasar emission lines. Using this technique, we detect microlensing of the continuum in 85% of the systems. Among them, 80% show microlensing of the broad emission lines. Focusing on the most common emission lines in our spectra (C III] and Mg II) we detect microlensing of either the blue or the red wing, or of both wings with the same amplitude. This observation implies that the broad line region is not in general spherically symmetric. In addition, the frequent detection of microlensing of the blue and red wings independently but not simultaneously with a different amplitude, does not support existing microlensing simulations of a biconical outflow. Our analysis also provides the intrinsic flux ratio between the lensed images and the magnitude of the microlensing affecting the continuum. These two quantities are particularly relevant for the determination of the fraction of matter in clumpy form in galaxies and for the detection of dark matter substructures via the identification of flux ratio anomalies. Based on observations made with the ESO-VLT Unit Telescope # 2 Kueyen (Cerro Paranal, Chile; Proposals 074.A-0563, 075.A-0377, 077.A-0155, PI: G. Meylan).Figure 1 and the new spectra presented in this paper are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/544/A62 and via the German virtual observatory http://dc.g-vo.org/mlqso/q/web/formAppendices are available in electronic form at http://www.aanda.org

Sluse, D.; Hutsemékers, D.; Courbin, F.; Meylan, G.; Wambsganss, J.

2012-08-01

32

VERY LARGE TELESCOPE SPECTROPOLARIMETRY OF BROAD ABSORPTION LINE QSOs  

SciTech Connect

We present spectropolarimetry of 19 confirmed and four possible bright, southern broad absorption line (BAL) quasars from the European Southern Observatory Very Large Telescope. A wide range of redshifts is covered in the sample (from 0.9 to 3.4), and both low- and high-ionization quasars are represented, as well as radio-loud and radio-quiet BALQSOs. We continue to confirm previously established spectropolarimetric properties of BALQSOs, including the generally rising continuum polarization with shorter wavelengths and comparatively large fraction with high broadband polarization (6 of 19 with polarizations >2%). Emission lines are polarized less than or similar to the continuum, except in a few unusual cases, and absorption troughs tend to have higher polarizations. A search for correlations between polarization properties has been done, identifying two significant or marginally significant correlations. These are an increase in continuum polarization with decreasing optical luminosity (increasing absolute B magnitude) and decreasing C IV emission-line polarization with increased continuum polarization.

DiPompeo, M. A.; Brotherton, M. S. [Department of Physics and Astronomy 3905, University of Wyoming, 1000 East University, Laramie, WY 82071 (United States); De Breuck, C. [European Southern Observatory, Karl Schwarzschild Strasse 2, 85748 Garching bei Muenchen (Germany)

2011-03-15

33

Variable High Velocity Winds from Broad Absorption Line Quasars  

NASA Astrophysics Data System (ADS)

We study broad absorption line quasars (BALQSOs) because these objects, in particular, probe the high velocity gas ejected by luminous accreting black holes. The variability timescales of BALs can help constrain the size, location, and dynamics of the emitting and absorbing gas near the supermassive black hole. We have obtained multi-epoch spectroscopy of seventeen BALQSOs from the Sloan Digital Sky Survey (SDSS) using the Fred Lawrence Whipple Observatory's 1.5m telescope's FAST Spectrograph. These objects were first identified as BALQSOs in SDSS, observed with Chandra, and then with FAST at 1, 3, 9, 27, and 81 day timescales. Additional observations are acquired for 1 and 2 year cadences. We also obtain a set of non-BAL quasar spectra of similar redshift and luminosity as controls. We identify significant variability and assess its magnitude and frequency in the observed spectra of our BAL QSOs and determine which constraints our investigations can put on the outflows impacting the BAL region.

Arraki, Kenza S.; Haggard, D.; Anderson, S.; Green, P.; Aldcroft, T.

2011-01-01

34

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

35

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

36

Radio Properties of Low Redshift Broad Line Active Galactic Nuclei  

E-print Network

The question as to whether the distribution of radio-loudness in active galactic nuclei (AGN) is actually bimodal has been discussed extensively in the literature. Futhermore, there have been claims that radio-loudness depends on black hole mass and Eddington ratio. We investigate these claims using the low redshift broad line AGN sample of Greene & Ho (2007), which consists of 8434 objects at z 10) and radio-quiet (RQ, R fashion for all subsamples. We find that 4.7% of the AGN in the flux-limited subsample are RL based on core radio emission alone. We calculate the radio-loud fraction (RLF) as both a function of black hole mass and Eddington ratio. The RLF decreases (from 13% to 2%) as Eddington ratio increases over 2.5 orde r of magnitude. The RLF is nearly constant (~5%) over 4 decades in black hole mass, except for an increase at masses greater than 10^8 solar masses. We find for the FIRST detected subsample th...

Rafter, Stephen E; Wiita, Paul J

2008-01-01

37

Radio Properties of Low Redshift Broad Line Active Galactic Nuclei  

E-print Network

The question as to whether the distribution of radio-loudness in active galactic nuclei (AGN) is actually bimodal has been discussed extensively in the literature. Futhermore, there have been claims that radio-loudness depends on black hole mass and Eddington ratio. We investigate these claims using the low redshift broad line AGN sample of Greene & Ho (2007), which consists of 8434 objects at z 10) and radio-quiet (RQ, R fashion for all subsamples. We find that 4.7% of the AGN in the flux-limited subsample are RL based on core radio emission alone. We calculate the radio-loud fraction (RLF) as both a function of black hole mass and Eddington ratio. The RLF decreases (from 13% to 2%) as Eddington ratio increases over 2.5 order of magnitude. The RLF is nearly constant (~5%) over 4 decades in black hole mass, except for an increase at masses greater than 10^8 solar masses. We find for the FIRST detected subsample that 367 of the RL AGN have black hole masses less than 10^8 solar masses, a large enough number to indicate that RL AGN are not a product of only the most massive black holes in the local universe.

Stephen E. Rafter; D. Michael Crenshaw; Paul J. Wiita

2008-09-23

38

THE VIEWING ANGLES OF BROAD ABSORPTION LINE VERSUS UNABSORBED QUASARS  

SciTech Connect

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

DiPompeo, M. A.; Brotherton, M. S. [Department of Physics and Astronomy 3905, University of Wyoming, 1000 E. University, Laramie, WY 82071 (United States); De Breuck, C. [European Southern Observatory, Karl Schwarzschild Strasse 2, 85748 Garching bei Muenchen (Germany)

2012-06-10

39

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

40

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

41

A broad-line region origin for the iron K? line in NGC 7213  

NASA Astrophysics Data System (ADS)

The X-ray spectrum of NGC 7213 is known to present no evidence for Compton reflection, a unique result among bright Seyfert 1s. The observed neutral iron K? line, therefore, cannot be associated with a Compton-thick material, like the disc or the torus, but is due to Compton-thin gas, with the broad-line region (BLR) as the most likely candidate. To check this hypothesis, a long Chandra High-Energy Transmission Grating observation, together with a quasi-simultaneous optical spectroscopic observation at the ESO NTT EMMI were performed. We found that the iron line is resolved with a full width at half-maximum (FWHM) = 2400+1100-600kms-1, in perfect agreement with the value measured for the broad component of the H?, 2640+110-90kms-1. Therefore, NGC 7213 is the only Seyfert 1 galaxy whose iron K? line is unambiguously produced in the BLR. We also confirmed the presence of two ionized iron lines and studied them in greater detail than before. The resonant line is the dominant component in the Fe XXV triplet, therefore suggesting an origin in collisionally ionized gas. If this is the case, the blueshift of around 1000kms-1 of the two ionized iron lines could be the first measure of the velocity of a starburst wind from its X-ray emission.

Bianchi, Stefano; La Franca, Fabio; Matt, Giorgio; Guainazzi, Matteo; Jimenez Bailón, Elena; Longinotti, Anna Lia; Nicastro, Fabrizio; Pentericci, Laura

2008-09-01

42

A sensitive submillimetre survey of broad absorption-line quasars  

NASA Astrophysics Data System (ADS)

Using the Submillimetre Common-User Bolometer Array on the JCMT, we have carried out a submillimetre (submm) survey of broad absorption-line quasars (BALQs). The sample has been chosen to match, in redshift and optical luminosity, an existing benchmark 850-?m sample of radio-quiet quasars, allowing a direct comparison of the submm properties of BAL quasars relative to the parent radio-quiet population. We reach a submm limit 1? ~ 1.5 mJy at 850 ?m, allowing a more rigorous measure of the submm properties of BAL quasars than previous studies. Our submm photometry complements extensive observations at other wavelengths, in particular X-rays with Chandra and infrared with Spitzer. To compare the 850-?m flux distribution of BALQs with that of the non-BAL quasar benchmark sample, we employ a suite of statistical methods, including survival analysis and a novel Bayesian derivation of the underlying flux distribution. Although there are no strong grounds for rejecting the null hypothesis that BALQs on the whole have the same submm properties as non-BAL quasars, we do find tentative evidence (1-4 per cent significance from a Kolmogorov-Smirnov test and survival analysis) for a dependence of submm flux on the equivalent width of the characteristic CIV BAL. If this effect is real - submm activity is linked to the absorption strength of the outflow - it has implications either for the evolution of active galactic nuclei (AGNs) and their connection with star formation in their host galaxies, or for unification models of AGNs.

Priddey, Robert S.; Gallagher, S. C.; Isaak, K. G.; Sharp, R. G.; McMahon, R. G.; Butner, H. M.

2007-01-01

43

Broad absorption line variability in radio-loud quasars  

NASA Astrophysics Data System (ADS)

We investigate C IV broad absorption line (BAL) variability within a sample of 46 radio-loud quasars (RLQs), selected from Sloan Digital Sky Survey (SDSS)/Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) data to include both core-dominated (39) and lobe-dominated (7) objects. The sample consists primarily of high-ionization BAL quasars, and a substantial fraction have large BAL velocities or equivalent widths; their radio luminosities and radio-loudness values span ˜2.5 orders of magnitude. We have obtained 34 new Hobby-Eberly Telescope spectra of 28 BAL RLQs to compare to earlier SDSS data, and we also incorporate archival coverage (primarily dual-epoch SDSS) for a total set of 78 pairs of equivalent width measurements for 46 BAL RLQs, probing rest-frame time-scales of ˜80-6000 d (median 500 d). In general, only modest changes in the depths of segments of absorption troughs are observed, akin to those seen in prior studies of BAL radio-quiet quasars (RQQs). Also similar to previous findings for RQQs, the RLQs studied here are more likely to display BAL variability on longer rest-frame time-scales. However, typical values of |{?}EW| and |{?}EW|/ are ˜40 ± 20 per cent lower for BAL RLQs when compared with those of a time-scale-matched sample of BAL RQQs. Optical continuum variability is of similar amplitude in BAL RLQs and BAL RQQs; for both RLQs and RQQs, continuum variability tends to be stronger on longer time-scales. BAL variability in RLQs does not obviously depend upon their radio luminosities or radio-loudness values, but we do find tentative evidence for greater fractional BAL variability within lobe-dominated RLQs. Enhanced BAL variability within more edge-on (lobe-dominated) RLQs supports some geometrical dependence to the outflow structure.

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

2014-05-01

44

Interpreting broad emission-line variations - I. Factors influencing the emission-line response  

NASA Astrophysics Data System (ADS)

We investigate the sensitivity of the measured broad emission-line responsivity dlog fline/dlog fcont to continuum variations in the context of straw-man broad emission-line region (BLR) geometries of varying size with fixed BLR boundaries, and for which the intrinsic emission-line responsivity is known a priori. We find for a generic emission line that the measured responsivity ?eff, delay and maximum of the cross-correlation function are correlated for characteristic continuum variability time-scales Tchar less than the maximum delay for that line ?max(line) for a particular choice of BLR geometry and observer orientation. The above correlations are manifestations of geometric dilution arising from reverberation effects within the spatially extended BLR. When present, geometric dilution reduces the measured responsivity, delay and maximum of the cross-correlation function. Conversely, geometric dilution is minimized if Tchar ? ?max(line). We also find that the measured responsivity and delay show a strong dependence on light-curve duration, with shorter campaigns resulting in smaller than expected values, and only a weak dependence on sampling rate (for irregularly sampled data). The observed strong negative correlation between continuum level and line responsivity found in previous studies cannot be explained by differences in the sampling pattern, light-curve duration or in terms of purely geometrical effects. To explain this and to satisfy the observed positive correlation between continuum luminosity and BLR size in an individual source, the responsivity-weighted radius must increase with increasing continuum luminosity. For a BLR with fixed inner and outer boundaries this requires radial surface emissivity distributions which deviate significantly from a simple power law, and in such a way that the intrinsic emission-line responsivity increases towards larger BLR radii, in line with photoionization calculations.

Goad, M. R.; Korista, K. T.

2014-10-01

45

What Drives the Outflows in Broad Absorption Line QSOs?  

NASA Technical Reports Server (NTRS)

We have made progress in the areas related to the propulsion and confinement of gas responsible for broad absorption troughts in QSOs: Radiative Acceleration in BALQSOs; The "Ghost" of Lyman (alpha); and Magnetic Confinement of Absorbing Gas.

Begelman, Mitchell C.

1997-01-01

46

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

47

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

48

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

49

A broad iron line in LMC X-1  

NASA Astrophysics Data System (ADS)

We present results from a deep Suzaku observation of the black hole in LMC X-1, supplemented by coincident monitoring with the Rossi X-ray Timing Explorer (RXTE). We identify broad relativistic reflection features in a soft disc-dominated spectrum. A strong and variable power-law component of emission is present which we use to demonstrate that enhanced Comptonization strengthens disc reflection. We constrain the spin parameter of the black hole by modelling LMC X-1's broad reflection features. For our primary and most comprehensive spectral model, we obtain a high value for the spin: a*=0.97-0.13+0.01 (68 per cent confidence). However, by additionally considering two alternate models as a measure of our systematic uncertainty, we obtain a broader constraint: a*=0.97-0.25+0.02. Both of these spin values are entirely consistent with a previous estimate of spin obtained using the continuum-fitting method. At 99 per cent confidence, the reflection features require a* > 0.2. In addition to modelling the relativistically broadened reflection, we also model a sharp and prominent reflection component that provides strong evidence for substantial reprocessing in the wind of the massive companion. We infer that this wind sustains the ionization cone surrounding the binary system; this hypothesis naturally produces appropriate and consistent mass, time and length scales for the cone structure.

Steiner, James F.; Reis, Rubens C.; Fabian, Andrew C.; Remillard, Ronald A.; McClintock, Jeffrey E.; Gou, Lijun; Cooke, Ryan; Brenneman, Laura W.; Sanders, Jeremy S.

2012-12-01

50

A Broad Iron Line in LMC X-1  

E-print Network

We present results from a deep Suzaku observation of the black hole in LMC X-1, supplemented by coincident monitoring with RXTE. We identify broad relativistic reflection features in a soft disc-dominated spectrum. A strong and variable power-law component of emission is present which we use to demonstrate that enhanced Comptonisation strengthens disc reflection. We constrain the spin parameter of the black hole by modelling LMC X-1's broad reflection features. For our primary and most comprehensive spectral model, we obtain a high value for the spin: a* = 0.97(+0.01,-0.13) (68 per cent confidence). However, by additionally considering two alternate models as a measure of our systematic uncertainty, we obtain a broader constraint: a* = 0.97(+0.02,-0.25). Both of these spin values are entirely consistent with a previous estimate of spin obtained using the continuum-fitting method. At 99 per cent confidence, the reflection features require a* > 0.2. In addition to modelling the relativistically broadened reflection, we also model a sharp and prominent reflection component that provides strong evidence for substantial reprocessing in the wind of the massive companion. We infer that this wind sustains the ionisation cone surrounding the binary system; this hypothesis naturally produces appropriate and consistent mass, time, and length scales for the cone structure.

James F. Steiner; Rubens C. Reis; Andrew C. Fabian; Ronald A. Remillard; Jeffrey E. McClintock; Lijun Gou; Ryan Cooke; Laura W. Brenneman; Jeremy S. Sanders

2012-09-14

51

Line variability and the broad emission line region of quasi-stellar objects. II - Changes in Balmer decrements  

NASA Technical Reports Server (NTRS)

Evidence is presented for significant variations of broad emission lines in five QSOs supporting an earlier report by Zheng et al. (1987). The Balmer decrements before and after variations are compared in an effort to extract information on the broad-line regions. The broad hydrogen lines are found to vary in step with the underlying continuum, indicating that the continuum is the probable energy source for emission lines. The ratios of H-beta/H-alpha for both the varying and steady parts of the the broad lines are about 0.2, suggesting that the regions in which these line fluxes originate are exposed to similar ionizing flux and are therefore at about the same distance to the central source. The average ratio of H-gamma/H-beta is 0.8 for the variable components, considerably higher than that of the constant components. Thus, the region producing the varying line fluxes may have higher density and lower optical depth.

Zheng, Wei

1988-01-01

52

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

E-print Network

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 [SII] doublet to subtract the contribution of the narrow emission lines to the H-alpha+[NII] complex and to isolate the BLR emission. Significant residuals that suggest a BLR, are present. However, the results change substantially when the [OI] doublet is used. Furthermore, the spectra are also reproduced well by just including a wing in the narrow H-alpha and [NII] lines, thus not requiring the presence of a BLR. We conclude that 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 5 Seyferts, and 5 LINERs. However, the measu...

Balmaverde, B; di Torino, INAF - Osservatorio Astrofisico

2014-01-01

53

Variability in quasar broad absorption line outflows - II. Multi-epoch monitoring of Si IV and C IV broad absorption line variability  

NASA Astrophysics Data System (ADS)

Broad absorption lines (BALs) in quasar spectra indicate high-velocity outflows that may be present in all quasars and could be an important contributor to feedback to their host galaxies. Variability studies of BALs help illuminate the structure, evolution and basic physical properties of the outflows. Here we present further results from an ongoing BAL monitoring campaign of a sample of 24 luminous quasars at redshifts 1.2 < z < 2.9. We directly compare the variabilities in the C IV?1549 and Si IV?1400 absorption to try to ascertain the cause(s) of the variability. We find that Si IV BALs are more likely to vary than C IV BALs. When looking at flow speeds >-20 000 km s-1, 47 per cent of quasars exhibited Si IV variability while 31 per cent exhibited C IV variability. Furthermore, ˜50 per cent of the variable Si IV regions did not have corresponding C IV variability at the same velocities, while nearly all occurrences of C IV variability had corresponding changes in Si IV. We do not find any correlation between the absolute change in strength in C IV and in Si IV, but the fractional change in strength tends to be greater in Si IV than in C IV. When both C IV and Si IV varied, those changes always occurred in the same sense (either getting weaker or stronger). We also include our full data set so far in this paper, which includes up to 10 epochs of data per quasar. The multi-epoch data show that the BAL changes were not generally monotonic across the full ˜5-8 yr time span of our observations, suggesting that the characteristic time-scale for significant line variations, and (perhaps) for structural changes in the outflows, is less than a few years. Coordinated variabilities between absorption regions at different velocities in individual quasars seem to favour changing ionization of the outflowing gas as the cause of the observed BAL variability. However, variability in limited portions of broad troughs fits naturally in a scenario where movements of individual clouds, or substructures in the flow, across our lines of sight cause the absorption to vary. The actual situation may be a complex mixture of changing ionization and cloud movements. Further discussion of the implications of variability, e.g. in terms of the size and location of the outflowing gas, will be presented in a forthcoming paper.

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

2012-06-01

54

Modeling line-driven disk wind for broad absorption lines of quasars  

E-print Network

The disk wind, which is powered by the radiation force due to spectral lines (line force), is studied for broad absorption line (BAL) quasars. We investigate the structure of the disk wind based on the non-hydrodynamic method and compare with wind properties inferred from X-ray observations of BAL quasars. In this paper, we apply the stellar wind theory to the initial condition (the mass outflow rate at the base of the wind). We found the funnel-shaped winds with a half opening angle of 50^{circ} for the case of epsilon=0.3-0.9 and M_{BH}=10^{7-8.5}M_odot, where epsilon is the Eddington ratio and M_{BH} is the black hole mass. Thus, the absorption features are observed for an observer of which a viewing angle is around 50^{circ}. A probability of BAL quasars is 7-11%, which is roughly consistent the abundance ratio of BAL quasars, 10-15%. Here, the probability is estimated by the solid angle, that the absorbing features would be detected, divided by 4pi. In contrast, if the Eddington ratio is smaller than 0.0...

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

2012-01-01

55

Consequences of hot gas in the broad line region of active galactic nuclei  

NASA Technical Reports Server (NTRS)

Models for hot gas in the broad line region of active galactic nuclei are discussed. The results of the two phase equilibrium models for confinement of broad line clouds by Compton heated gas are used to show that high luminosity quasars are expected to show Fe XXVI L alpha line absorption which will be observed with spectrometers such as those planned for the future X-ray spectroscopy experiments. Two phase equilibrium models also predict that the gas in the broad line clouds and the confining medium may be Compton thick. It is shown that the combined effects of Comptonization and photoabsorption can suppress both the broad emission lines and X-rays in the Einstein and HEAO-1 energy bands. The observed properties of such Compton thick active galaxies are expected to be similar to those of Seyfert 2 nuclei. The implications for polarization and variability are also discussed.

Kallman, T.; Mushotzky, R.

1985-01-01

56

Consequences of hot gas in the broad-line region of active galactic nuclei  

NASA Technical Reports Server (NTRS)

Models for hot gas in the broad line region of active galactic nuclei are discussed. The results of the two phase equilibrium models for confinement of broad line clouds by Compton heated gas are used to show that high luminosity quasars are expected to show Fe XXVI L alpha line absorption which will be observed with spectrometers such as those planned for the future X-ray spectroscopy experiments. Two phase equilibrium models also predict that the gas in the broad line clouds and the confining medium may be Compton thick. It is shown that the combined effects of Comptonization and photoabsorption can suppress both the broad emission lines and X-rays in the Einstein and HEAO-1 energy bands. The observed properties of such Compton thick active galaxies are expected to be similar to those of Seyfert 2 nuclei. The implications for polarization and variability are also discussed.

Kallman, T.; Mushotzky, R.

1985-01-01

57

Probing Accretion Disk Winds in AGN - Asymmetric broad Balmer Emission Lines  

E-print Network

The Broad Line Region of Active Galactic Nuclei is characterized by broad Balmer emission lines in their optical spectra. The broad Balmer emission lines are found to be asymmetric, some blue sided and others red sided in their asymmetry. One of the components behind the asymmetry is thought to be an accretion disk wind. We probe the accretion disk wind using the broad balmer emission line profiles. This asymmetry of the broad balma emission line profiles is measured in velocity space after a measurement of the line shift at percentiles from 0, in increaments of 10, up to 90. In addition, the Kurtosis Index is obtained at appropriate points of the emission lines' profiles. This study is based on many hundreds of SDSS spectra, starting with low redshift high signal to noise ratio spectra. We also consider a definite number in each bin of their FWHM, in bins of 1000 km/s (atleast 40 per bin), starting from 1000km/s to the very broad emission lines. We present how strong the asymmetry (by plotting Asymmetry Inde...

Dumba, Cosmos

2014-01-01

58

ROSAT, ASCA, and OSSE Observations of the Broad-Line Radio Galaxy 3C 120  

NASA Astrophysics Data System (ADS)

We present simultaneous observations of the superluminal radio galaxy 3C 120 performed with the ASCA and GRO (OSSE) satellites in 1994 February-March, as well as an analysis of all the ROSAT archival data. The ASCA spectrum of this object can be described by an absorbed (NH = 1.6 × 1021 cm-2) power law with a photon index of ? ASCA = 2 and a very broad (? > 0.8 keV) intense iron line (EW > 400 eV) at ~6 keV. The combined ASCA-OSSE data do not exclude the presence of a narrower (? = 0.4 keV) and less intense (EW < 300 eV) iron line plus a hard component, corresponding either to reflection from an accretion disk or to a flatter power law from a jet. However, a single power law plus broad Fe line is preferred from a statistical point of view by the ASCA data. The ROSAT data yield a column density in excess of the Galactic value. The spectral slopes, ranging from ? ROSAT = 2.5 to 3.3, are steeper than that measured by ASCA, suggesting the presence of a soft excess. The 0.1-2 keV power-law slope is variable and softer at higher intensity. These results show that the combined soft and hard X-ray spectrum of 3C 120 is rather complex. The intrinsic absorption, the soft excess, and the iron line indicate that the X-ray emission from this blazar-like radio galaxy is dominated by a Seyfert-like component, at least in the 0.1-10 keV energy band. The jet contribution, if present, becomes important only at higher energies.

Grandi, P.; Sambruna, R. M.; Maraschi, L.; Matt, G.; Urry, C. M.; Mushotzky, R. F.

1997-10-01

59

The analysis of the broad hydrogen Balmer line ratios: Possible implications for the physical properties of the broad line region of AGNs  

NASA Astrophysics Data System (ADS)

Aims: We analyze the ratios of the broad hydrogen Balmer emission lines (from H? to H?) in the context of estimating the physical conditions in the broad line region (BLR) of active galactic nuclei (AGNs). Methods: Our measurements of the ratios of the Balmer emission lines are obtained in three ways: i) using photoionization models obtained with a spectral synthesis code CLOUDY; ii) applying the recombination theory for hydrogenic ions; iii) measuring the lines in observed spectra taken from the Sloan Digital Sky Survey database. We investigate the Balmer line ratios in the framework of the so-called Boltzmann plot (BP), analyzing the physical conditions of the emitting plasma for which we could use the BP method. The BP considers the ratio of Balmer lines normalized to the atomic data of the corresponding line transition, and in that way differs from the Balmer decrement. Results: We find that for a certain range of thermodynamic parameters, there are objects that follow the BP. These AGNs may have a BLR consisting of mostly high density plasma.

Ili?, D.; Popovi?, L. ?.; La Mura, G.; Ciroi, S.; Rafanelli, P.

2012-07-01

60

Millihertz quasi-periodic oscillations and broad iron line from LMC X-1  

NASA Astrophysics Data System (ADS)

We study the temporal and energy spectral characteristics of the persistent black hole X-ray binary LMC X-1 using two XMM-Newton and a Suzaku observation. We report the discovery of low-frequency (˜26-29 m Hz) quasi-periodic oscillations (QPOs). We also report the variability of the broad iron K? line studied earlier with Suzaku. The QPOs are found to be weak with fractional rms amplitude in the ˜1-2 per cent range and quality factor Q ˜ 2-10. They are accompanied by weak red noise or zero-centred Lorentzian components with rms variability at the ˜1-3 per cent level. The energy spectra consist of three varying components - multicolour disc blackbody (kTin ˜ 0.7-0.9 keV), high-energy power-law tail (? ˜ 2.4-3.3) and a broad iron line at 6.4-6.9 keV. The broad iron line, the QPO and the strong power-law component are not always present. The QPOs and the broad iron line appear to be clearly detected in the presence of a strong power-law component. The broad iron line is found to be weaker when the disc is likely truncated and absent when the power-law component almost vanished. These results suggest that the QPO and the broad iron line together can be used to probe the dynamics of the accretion disc and the corona.

Alam, Md. Shah; Dewangan, G. C.; Belloni, T.; Mukherjee, D.; Jhingan, S.

2014-12-01

61

X-Ray Absorbed, Broad-Lined, Red AGN and the Cosmic X-Ray Background  

NASA Technical Reports Server (NTRS)

We have obtained XMM spectra for five red, 2MASS AGN, selected from a sample observed by Chandra to be X-ray bright and to cover a range of hardness ratios. Our results confirm the presence of substantial absorbing material in three sources which have optical classifications ranging from Type 1 to Type 2, with an intrinsically flat (hard) power law continuum indicated in the other two. The presence of both X-ray absorption and broad optical emission lines with the usual strength suggests either a small (nuclear) absorber or a favored viewing angle so as to cover the X-ray source but not the broad emission line region (BELR). A soft excess is detected in all three Type 1 sources. We speculate that this soft X-ray emission may arise in an extended region of ionized gas, perhaps linked with the polarized (scattered) light which is a feature of these sources. The spectral complexity revealed by XMM emphasizes the limitations of the low S/N Chandra data. Overall, the new XMM results strengthen our conclusions (Wilkes et al. 2002) that the observed X-ray continua of red AGN are unusually hard at energies greater than 2 keV. Whether due to substantial line-of-sight absorption or to an intrinsically hard or reflection-dominated spectrum, these 'red' AGN have an observed spectral form consistent with contributing significantly to the missing had absorbed population of the Cosmic X-ray Background (CXRB). When absorption and or reflection is taken into account, all these AGN have power law slopes typical of broad-line (Type 1) AGN (Gamma approximately 1.9). This appears to resolve the spectral paradox which for so long has existed between the CXRB and the AGN thought to be the dominant contributors. It also suggests two scenarios whereby Type 1 AGN/QSOs may be responsible for a significant fraction of the CXRB at energies above 2 keV: 1) X-ray absorbed AGN/QSOs with visible broad emission lines; 2) AGN/QSOs with complex spectra whose hardness greater than 2 keV is not detectable in the typically low S/N data of X-ray surveys. Even if absorption is present in only half of the population, the large number of 'red' AGN suggests a development of unification models, where the continuum source is surrounded, over a substantial solid angle, by the wind or atmosphere of an accretion disk/torus. X-ray observations of such AGN not only provide a check on the presence of absorption, but also a unique probe of the absorbing material. Improved information on their space density, in particular as a function of redshift, will soon be provided by Spitzer-Chandra wide area surveys, allowing better estimates of both the importance of red AGN to the full AGN population and their contribution to the CXRB.

Mushotzky, Richard (Technical Monitor); Wilkes, Belinda

2005-01-01

62

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

E-print Network

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 alpha and Pa beta, and find that it scales with the ionising continuum luminosity roughly as expected from photoionisation 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 ...

Landt, Hermine; Elvis, Martin; Karovska, Margarita

2014-01-01

63

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

64

The Twice-Overlooked, Second FR II Broad Absorption Line Quasar LBQS 1138-0126  

E-print Network

We report the correct classification of an overlooked Fanaroff-Riley class II radio-loud quasar with broad absorption lines, only the second such object so identified. The rare properties of this quasar, LBQS 1138-0126, are twice overlooked. First LBQS 1138-0126 was found in the Large Bright Quasar Survey but only noted as a possible broad absorption line quasar without additional follow-up. Later LBQS 1138-0126 was rediscovered and classified as a radio-loud broad absorption line quasar but not recognized as an FR II radio source. We describe the radio, absorption line, and optical polarization properties of LBQS 1138-0126 and place it in context with respect to related quasars. In particular, spectropolarimetry shows that LBQS 1138-0126 has high continuum polarization increasing from 3% in the red (rest-frame 2400 Angstroms) to over 4% in the blue (rest-frame 1650 Ansgtroms), essentially confirming the intrinsic nature of the absorption. The polarization position angle rotates from about -30 degrees in the red to about 0 degrees in the blue; the radio lobe position angle is 52 degrees for comparison. LBQS 1138-0126 is additionally notable for being one of the most radio-loud broad absorption line quasars, and for having low-ionization broad absorption lines as well.

Michael S. Brotherton; Scott M. Croom; Carlos De Breuck; Robert H. Becker; Michael D. Gregg

2002-07-18

65

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

66

Broad absorption line quasars have the same cool dust emission as quasars without BALs  

E-print Network

The results of a sub-millimeter survey of SDSS broad CIV absorption line quasars is discussed. It is found that the sub-millimeter flux distribution of BAL quasars is similar to that of non-BAL quasars. This is consistent with the idea that all quasars contain broad absorption line regions, but only a fraction of them are visible along our line-of-sight. The observations are inconsistent with BAL quasars being observed at a special evolutionary epoch co-inciding with a high star-formation rate and dust mass.

Chris J. Willott; Steve Rawlings; Jennifer A. Grimes

2003-10-22

67

The Remarkable X-ray Spectrum of the Broad-Line Radio Galaxy 3C 445  

NASA Technical Reports Server (NTRS)

The nearby (z=0.057) radio-loud source 3C 445, optically classified as a Broad-Line Radio Galaxy, exhibits an X-ray spectrum strongly reminiscent of an obscured AGN, suggesting we are seeing this source at a relatively large angle from the radio jet. Here we present an archival 15 ks XMM-Newton observation of 3C 445 which confirms the remarkable complexity of its X-ray emission. The X-ray emission is described by a power law continuum with GAMMA approximately equal to 1.4, absorbed by several layers of cold gas, plus strong cold reflection. A narrow, unresolved Fe Kalpha emission line is detected, confirming previous findings, with EW approximately equal to 400 eV. A soft excess is present below 2 keV over the extrapolation of the hard X-ray power law, which we model with a power law with the same photon index and absorbed by a column density N(sub H)5 approximately equal to 10(sup 20) cm(sup -2) in excess to Galactic. Remarkably, a host of emission lines are present below 2 keV, confirming previous indications from ASCA, due to H- and He-like O, Mg, and Si. The detection of two features at 0.74 and 0.87 keV, identified with OVII and OVIII Radiative Recombination Continuum features, suggest an origin of the lines from a photoionized gas, with properties very similar to radio-quiet obscured AGN. Two different ionized media, or a single stratified medium, are required to fit the soft X-ray data satisfactorily. The similarity of the X-ray spectrum of 3C 445 to Seyferts underscores that the central engines of radio-loud and radio-quiet AGN similarly host both cold and warm gas.

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

2007-01-01

68

Structure of Broad Emission-Line Region in AGN and Obscuring Gas and Dust  

NASA Astrophysics Data System (ADS)

The structure of the broad emission-line region in an Active Galactic Nucleus and of the obscuring material that surrounds it are unclear. X-ray emission is clearly absorbed along some lines of sight, and the broad lines are reddened or completely missed. The obscuring material is distributed in an approximate disk geometry (either a warped disk or torus) and is quite possibly clumpy. Elitzur, Nenkova and collaborators have proposed a simple model whereby clouds distributed in an approximate torus geometry both produce the broad lines (from the innermost, hot region, in which dust is sublimated so only atomic gas is present) and redden or absorb light (along dusty lines of sight further away from the nucleus). We test this model using a hard X-ray-selected AGN sample (from the Swift BAT survey) that should be nearly unbiased with respect to orientation. We estimate the X-ray-absorbing column density, N_H, by fitting the spectrum with a plausible two-power-law model, and we estimate the reddening toward the broad-line region from Balmer line ratios. We compare these two measures of reddening in the context of the Elitzur et al. model.

Lazzarini, Margaret; Urry, C. M.; Glikman, E.; Elitzur, M.; LaMassa, S. M.; Schawinski, K.; Vasudevan, R.; Winter, L. M.; Koss, M.

2013-01-01

69

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

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

70

Eclipsing Broad Emission Lines in Hercules X-1: Evidence for a Disk Wind?  

E-print Network

We present disk wind model calculations for the broad emission lines seen in the ultraviolet spectra of the X-ray binary Hercules X-1. Recent HST/STIS observations of these lines suggest that they are kinematically linked to the orbital motion of the neutron star and exhibit a red-shifted to blue-shifted evolution of the line shape during the progression of the eclipse from ingress to egress which is indicative of disk emission. Furthermore, these lines are single-peaked which implies that they may be formed in a disk wind similar to those we have proposed as producing the broad emission lines seen in the UV spectra of active galactic nuclei. We compute line profiles as a function of eclipse phase and compare them to the observed line profiles. Various effects may modify the appearance of the lines including resonant scattering in the wind itself, self-shadowing of the warped disk from the central continuum, and self-obscuration of parts of the disk along the observer's line-of-sight. These latter two effects can cause orbital and precessional phase dependent variations in the emission lines. Hence, examination of the line profiles as a function of these phases can, in principle, provide additional information on the characteristics of the disk warp.

James Chiang

2000-11-05

71

Rejection of the Binary Broad-Line Region Interpretation of Double-Peaked Emission Lines in Three Active Galactic Nuclei  

E-print Network

It has been suggested that the peculiar double-peaked Balmer lines of certain broad-line radio galaxies come from individual broad-line regions associated with the black holes of a supermassive binary. We continue to search for evidence of the radial velocity variations characteristic of a double-lined spectroscopic binary that are required in such a model. After spectroscopic monitoring of three suitable candidates (Arp 102B, 3C 390.3, and 3C 332) spanning two decades, we find no such long-term systematic changes in radial velocity. A trend noticed by Gaskell in one of the Balmer-line peaks of 3C 390.3 before 1988 did not continue after that year, invalidating his inferred orbital period and mass. Instead, we find lower limits on the plausible orbital periods that would require the assumed supermassive binaries in all three objects to have total masses in excess of 10^10 solar masses. In the case of 3C 390.3 the total binary mass must exceed 10^11 solar masses to satisfy additional observational constraints on the inclination angle. Such large binary black hole masses are difficult to reconcile with other observations and with theory. In addition, there are peculiar properties of the line profiles and flux ratios in these objects that are not explained by ordinary broad-line region cloud models. We therefore doubt that the double-peaked line profiles of the three objects arise in a pair of broad-line regions. Rather, they are much more likely to be intimately associated with a single black hole.

M. Eracleous; J. P. Halpern; A. M. Gilbert; J. A. Newman; A. V. Filippenko

1997-06-20

72

AGN with faint broad line regions: Some `True'-Seyfert 2s might be Narrow Line Seyfert 1s  

NASA Astrophysics Data System (ADS)

The intriguing existence of `True'-Seyfert 2s has opened a debate on the validity of the unified model of active galactic nuclei (AGN). These objects, also called `Naked'-AGN, seem to lack a broad line region. In some cases, their X-ray emission is unabsorbed, typical of Seyfert 1 galaxies, indicating a clear view toward the nucleus, but no broad lines are seen in the optical. In `True'-Seyfert 2s with higher column densities, observations of polarized light have failed to reveal the hidden broad emission. We performed high-resolution near-infrared integral-field observations of two `True'-Seyfert 2 candidates: IRAS 01072+4954 and NGC 7496. We found that the AGN in these sources might power very faint and narrow broad emission lines (FWHMbroad < 1500km s-1). Here, we discuss the properties of the broad components estimated from published X-ray and/or optical measurements and present their near-infrared candidate identification. Both galaxies host intermediate-mass black holes, with masses ~ 105-106 M?. Our results favor the unified model in the cases of high accretion rates, and stress the necessity of a multiwavelength approach to unveil the nature of `Naked'-AGN.

Valencia-S., Mónica; Busch, G.; Smaji?, S.; Fazeli, N.; Behroozian, S.; Zuther, J.; Fischer, S.; Eckart, A.

2014-07-01

73

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

SciTech Connect

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

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

2010-11-01

74

NGC 5548 in a Low-Luminosity State: Implications for the Broad-Line Region  

NASA Astrophysics Data System (ADS)

We describe results from a new ground-based monitoring campaign on NGC 5548, the best-studied reverberation-mapped AGN. We find that it was in the lowest luminosity state yet recorded during a monitoring program, namely L5100=4.7×1042 ergs s-1. We determine a rest-frame time lag between flux variations in the continuum and the H? line of 6.3+2.6-2.3 days. Combining our measurements with those of previous campaigns, we determine a weighted black hole mass of MBH=6.54+0.26-0.25×107 Msolar based on all broad emission lines with suitable variability data. We confirm the previously discovered virial relationship between the time lag of emission lines relative to the continuum and the width of the emission lines in NGC 5548, which is the expected signature of a gravity-dominated broad-line region. Using this lowest luminosity state, we extend the range of the relationship between the luminosity and the time lag in NGC 5548 and measure a slope that is consistent with ?=0.5, the naive expectation for the broad-line region for an assumed form of r~L?. This value is also consistent with the slope recently determined by Bentz et al. for the population of reverberation-mapped AGNs as a whole.

Bentz, Misty C.; Denney, Kelly D.; Cackett, Edward M.; Dietrich, Matthias; Fogel, Jeffrey K. J.; Ghosh, Himel; Horne, Keith D.; Kuehn, Charles; Minezaki, Takeo; Onken, Christopher A.; Peterson, Bradley M.; Pogge, Richard W.; Pronik, Vladimir I.; Richstone, Douglas O.; Sergeev, Sergey G.; Vestergaard, Marianne; Walker, Matthew G.; Yoshii, Yuzuru

2007-06-01

75

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

SciTech Connect

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

Pettini, M.; Boksenberg, A.

1985-07-01

76

Physical properties of the broad line region in active galactic nuclei  

NASA Astrophysics Data System (ADS)

We present here the study of the plasma in the broad line region (BLR) of active galactic nuclei (AGN). In order to probe the physical properties of the emitting plasma in the BLR we analyze the fluxes of the following broad emission lines (BELs): the hydrogen Balmer lines (H? to H?) and the helium lines from two subsequent ionization levels (He II ?4686 and He I ?5876). The BELs are obtained from the spectral synthesis photoionization code CLOUDY. We investigate these BELs in order to find conditions in the BLR where so-called Boltzmann-plot (BP) can be applied, and we found that in a number of modeled spectra it is working. We used these spectra to explore the dependence between plasma parameters (e.g. the averaged temperature, hydrogen density, etc.) and the ratio of He II ?4686 and He I ?5876 lines. In this progress report we present our investigation of the emitting plasma in the BLR using the most intensive broad spectral lines in AGN spectra.

Ili?, Dragana; Popovi?, Luka ?.; Ciroi, Stefano; La Mura, Giovanni; Rafanelli, Piero

2010-11-01

77

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

78

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

79

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

80

TIME VARIABLE BROAD-LINE EMISSION IN NGC 4203: EVIDENCE FOR STELLAR CONTRAILS  

SciTech Connect

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{alpha} 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 {approx}1500 AU from the central black hole. There is also a bright core of broad H{alpha} line emission that is not time variable and identified with a large-scale inflow from an outer radius of {approx}1 pc. If the gas number density is {>=}10{sup 6} cm{sup -3}, as suggested by the absence of similarly broad [O I] and [O III] emission lines, then the steady state inflow rate is {approx} 2 Multiplication-Sign 10{sup -2} M{sub Sun} yr{sup -1}, which exceeds the inflow requirement to explain the X-ray luminosity in terms of radiatively inefficient accretion by a factor of {approx}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{alpha} 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, E-mail: devereux@erau.edu [Department of Physics, Embry-Riddle Aeronautical University, Prescott, AZ 86301 (United States)

2011-12-10

81

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

82

Structure of the Accretion Flows in Broad-Line Radio Galaxies  

NASA Technical Reports Server (NTRS)

The goal of this project was to obtain high-signal-to-noise ratio X-ray spectra of broad-line radio galaxies in order to compare the properties of their Fe K(alpha) lines with those of their radio-quiet counterparts, the Seyfert galaxies. By fitting the line profiles with relativistic disk models, it is possible to determine the range of radii in the disk where the lines originate and thus test models for the inner accretion disk. More specifically, geometrically thin disk models place the origin of the line very close to the innermost stable orbit of the disk, while models of advection dominated accretion flows require the lines to originate at larger distances from the central black hole, of order a few hundred gravitational radii.

Eracleous, Michael

2002-01-01

83

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

84

Plasma Properties of the Broad Line Emitting Region in Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

In order to probe the physical properties of the emitting plasma in the broad line region (BLR) of active galactic nuclei (AGN), we perform a number of numerical simulations with the photoionization code CLOUDY. We investigate the Balmer and helium line ratios in order to find conditions in the BLR where so-called Boltzmann-plot (BP) method is applicable. We found correlations between average temperature, hydrogen density and He II/He I line ratio in the case where BP is present.

Ili?, D.; Popovi?, L. ?.; Ciroi, S.; La Mura, G.; Rafanelli, P.

2009-04-01

85

NGC 3147: a `true' type 2 Seyfert galaxy without the broad-line region  

NASA Astrophysics Data System (ADS)

We report on simultaneous optical and X-ray observations of the Seyfert galaxy, NGC 3147. The XMM-Newton spectrum shows that the source is unabsorbed in the X-rays (NH < 5 × 1020 cm-2). On the other hand, no broad lines are present in the optical spectrum. The origin of this optical/X-rays misclassification (with respect to the Unification Model) cannot be attributed to variability, since the observations in the two bands are simultaneous. Moreover, a Compton-thick nature of the object can be rejected on the basis of the low-equivalent width of the iron K? line (~=130 eV) and the large ratio between the 2-10 keV and the [OIII] fluxes. It seems therefore inescapable to conclude that NGC 3147 intrinsically lacks the Broad-Line Region, making it the first `true' type 2 Seyfert galaxy.

Bianchi, S.; Corral, A.; Panessa, F.; Barcons, X.; Matt, G.; Bassani, L.; Carrera, F. J.; Jiménez-Bailón, E.

2008-03-01

86

NGC 3147: a 'true' type 2 Seyfert galaxy without the broad-line region  

NASA Astrophysics Data System (ADS)

We report on simultaneous optical and X-ray observations of the Seyfert galaxy, NGC3147. The XMM-Newton spectrum shows that the source is unabsorbed in the X-rays ( N_H < 5 10^20 cm ^-2 ). On the other hand, no broad lines are present in the optical spectrum. The origin of this optical/X-rays misclassification (with respect to the Unification Model) cannot be attributed to variability, since the observations in the two bands are simultaneous. Moreover, a Compton-thick nature of the object can be rejected on the basis of the low equivalent width of the iron K alpha line ( ~eq 130 eV) and the large ratio between the 2-10 keV and the [OIII] fluxes. It seems therefore inescapable to conclude that NGC3147 intrinsically lacks the Broad Line Region (BLR), making it the first 'true' Seyfert 2.

Bianchi, S.; Corral, A.; Panessa, F.; Barcons, X.; Matt, G.; Bassani, L.; Carrera, F. J.; Jiménez-Bailón, E.

2008-10-01

87

Double-Peaked Broad Emission Lines in NGC 4450 and Other LINERs  

E-print Network

Spectra taken with 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 the observed profile with a model for a disk with a radial range of 1000-2000 gravitational radii and inclined by 27 degrees along the line of sight. The small-aperture HST data also allow us to detect, for the first time, the featureless continuum at optical wavelengths in NGC 4450; the nonstellar nucleus is intrinsically very faint, with M_B = -11.2 mag for D = 16.8 Mpc. We have examined the multiwavelength properties of NGC 4450 collectively with those of other low-luminosity active nuclei which possess double-peaked broad lines and find a number of common features. These objects are all classified spectroscopically as "type 1" LINERs or closely related objects. The nuclear luminosities are low, both in absolute terms and relative to the Eddington rates. All of them have compact radio cores, whose strength relative to the optical nuclear emission places them in the league of radio-loud active nuclei. The broad-band spectral energy distributions of these sources are most notable for their deficit of ultraviolet emission compared to those observed in luminous Seyfert 1 nuclei and quasars. The double-peaked broad-line radio galaxies Arp 102B and Pictor A have very similar attributes. We discuss how these characteristics can be understood in the context of advection-dominated accretion onto massive black holes.

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

2000-04-28

88

BROAD IRON LINES IN NEUTRONS STARS: DYNAMICAL BROADENING OR WIND SCATTERING?  

SciTech Connect

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

Cackett, Edward M. [Department of Physics and Astronomy, Wayne State University, 666 W. Hancock Street, Detroit, MI 48201 (United States); Miller, Jon M., E-mail: ecackett@wayne.edu [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48105 (United States)

2013-11-01

89

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

90

Active Galaxies With Double-Peaked Emission Lines and What They Imply About the "Broad-Line Region"  

E-print Network

I review the distinguishing observational characteristics of active galaxies with double-peaked emission lines and their implications for the nature of the line-emitting region. Since double-peaked lines most likely originate in the outer parts of the accretion disk, they can be used to study the structure and dynamics of the disk and the associated wind. Such studies lead to general inferences about the broad-line regions of all AGNs. To this end, I describe the results of recent UV spectroscopy of double-peaked emitters that probes the disk-wind relation. I also summarize efforts to exploit the variability of the lines to study dynamical and thermal phenomena in the disk.

Michael Eracleous

2003-10-22

91

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

92

Low frequency QPOs and Variable Broad Iron line from LMC X-1  

NASA Astrophysics Data System (ADS)

We have performed temporal and energy spectral study of the persistent black hole X-ray binary LMC X-1 using XMM-Newton, Suzaku and RXTE observations. We report the discovery of low frequency (26-56 mHz) QPOs and variable broad iron line from LMC X-1. The QPOs are generally weak with rms amplitudes in the 1-6% range and coherence (quality factor Q˜2-10). The QPOs are accompanied by weak red-noise with rms variability in the 1.3-4% level. The energy spectra of LMC X-1 consist of three components - multicolor disk blackbody (kT˜0.7-0.9 keV), high energy power law tail (photon index ˜2.4-3.3), and broad iron line at 6.4-6.9 keV. The QPOs were detected only in the presence of a strong powerlaw component. The strong broad and relativistic iron line was observed in the presence of both the strong powerlaw and an accretion disk extending to the innermost regions. The iron line is found to be weaker when the disk is truncated and absent when the powerlaw component almost vanished. Our results imply that LMC X-1 does not always remain in the canonical soft state but also transits to the soft intermediate or the steep powerlaw state.

Dewangan, G.; Alam, S.; Belloni, T.; Mukherjee, D.; Jhingan, S.

2014-07-01

93

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

NASA Astrophysics Data System (ADS)

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

Punsly, Brian

1999-12-01

94

Locally Optimally Emitting Clouds and the Variable Broad Emission Line Spectrum of NGC 5548  

NASA Astrophysics Data System (ADS)

In recent work Baldwin et al. proposed that in the geometrically extended broad-line regions (BLRs) of quasars and active galactic nuclei, a range in line-emitting gas properties (e.g., density, column density) might exist at each radius and showed that under these conditions the broad emission line spectra of these objects may be dominated by selection effects introduced by the atomic physics and general radiative transfer within the large pool of line-emitting entities. In this picture, the light we see originates in a vast amalgam of emitters but is dominated by those emitters best able to reprocess the incident continuum into a particular emission line. We test this ``locally optimally emitting clouds'' (LOC) model against the extensive spectroscopic database of the Seyfert 1 galaxy NGC 5548. The time-averaged, integrated-light UV broad emission line spectrum from the 1993 Hubble Space Telescope (HST) monitoring campaign is reproduced via the optimization of three global geometric parameters: the outer radius, the index controlling the radial cloud covering fraction of the continuum source, and the integrated cloud covering fraction. We make an ad hoc selection from the range of successful models, and for a simple spherical BLR geometry we simulate the emission-line light curves for the 1989 IUE and 1993 HST campaigns, using the respective observed UV continuum light curves as drivers. We find good agreement between the predicted and observed light curves and lags-a demonstration of the LOC picture's viability as a means to understanding the BLR environment. Finally, we discuss the next step in developing the LOC picture, which involves the marriage of echo-mapping techniques with spectral simulation grids such as those presented here, using the constraints provided by a high-quality, temporally well-sampled spectroscopic data set.

Korista, Kirk T.; Goad, Michael R.

2000-06-01

95

Constraining Variable High Velocity Winds from Broad Absorption Line Quasars with Multi-Epoch Spectroscopy  

NASA Astrophysics Data System (ADS)

Broad absorption line (BAL) quasars probe the high-velocity gas ejected by luminous accreting black holes. BAL variability timescales place constraints on the size, location, and dynamics of the emitting and absorbing gas near the supermassive black hole. We present multi-epoch spectroscopy of seventeen BAL QSOs from the Sloan Digital Sky Survey (SDSS) using the Fred Lawrence Whipple Observatory's 1.5m telescope's FAST Spectrograph. These objects were identified as BALs in SDSS, observed with Chandra, and then monitored with FAST at observed-frame cadences of 1, 3, 9, 27, and 81 days, as well as 1 and 2 years. We also monitor a set of non-BAL quasars with matched redshift and luminosity as controls. We identify significant variability in the BALs, particularly at the 1 and 2 year cadences, and use its magnitude and frequency to constrain the outflows impacting the broad absorption line region.

Haggard, D.; Arraki, K. S.; Green, P. J.; Aldcroft, T.; Anderson, S. F.

2012-08-01

96

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

97

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

Microsoft Academic Search

This article is an analysis of the broad absorption line properties of a theory of quasars described in a companion paper (Paper I) that differentiates radio-loud quasars from radio-quiet quasars by the magnetic field structure, or lack thereof, in the vortex of an accretion flow around a supermassive rapidly rotating black hole. Nonmagnetic vortices (the radio-quiet case) can initiate radiation

Brian Punsly

1999-01-01

98

The Link between the Hidden Broad Line Region and the Accretion Rate in Seyfert 2 Galaxies  

NASA Astrophysics Data System (ADS)

In the past few years, more and more pieces of evidence have been presented for a revision of the widely accepted unified model of active galactic nuclei. A model based solely on orientation cannot explain all the observed phenomenology. In the following, we will present evidence that accretion rate is also a key parameter for the presence of hidden broad line regions (HBLRs) in Seyfert 2 galaxies. Our sample consists of 21 sources with polarized hidden broad lines and 18 sources without hidden broad lines. We use stellar velocity dispersions from several studies on the Ca II and Mg b triplets in Seyfert 2 galaxies to estimate the mass of the central black holes via the M BH-?sstarf relation. The ratio between the bolometric luminosity, derived from the intrinsic (i.e., unabsorbed) X-ray luminosity, and the Eddington luminosity is a measure of the rate at which matter accretes onto the central supermassive black hole. A separation between Compton-thin HBLR and non-HBLR sources is clear, both in accretion rate (log L bol/L Edd = -1.9) and in luminosity (log L bol = 43.90). When properly luminosity-corrected Compton-thick sources are included, the separation between HBLR and non-HBLR is less sharp but no HBLR source falls below the Eddington ratio threshold. We speculate that non-HBLR Compton-thick sources with accretion rate higher than the threshold do possess a BLR, but something, probably related to their heavy absorption, is preventing us from observing it even in polarized light. Our results for Compton-thin sources support theoretical expectations. In a model presented by Nicastro, the presence of broad emission lines is intrinsically connected with disk instabilities occurring in proximity of a transition radius, which is a function of the accretion rate, becoming smaller than the innermost stable orbit for very low accretion rates and therefore luminosities.

Marinucci, Andrea; Bianchi, Stefano; Nicastro, Fabrizio; Matt, Giorgio; Goulding, Andy D.

2012-04-01

99

A new sample of broad-absorption-line quasars exhibiting the ghost of lyman alpha  

E-print Network

We have searched the broad-absorption-line quasar (BAL QSO) sample presented by Reichard et al. for objects exhibiting the so-called `ghost of Lyman alpha'. This ghost manifests as a hump near -5900kms in the troughs of the broad absorption lines and provides strong evidence for the importance of line-driving in powering the outflows from BAL QSOs. Of the 224 sample BAL QSOs selected from the Sloan Digital Sky Survey (SDSS) Early Data Release (EDR), 198 satisfy our redshift constraints and 58 show clear evidence of multiple-trough (MT) structure in the CIV line. A composite spectrum constructed from this MT sample already shows evidence for a ghost feature. Narrowing our classification scheme further, we define a set of 36 objects that individually show evidence of a ghost feature, and then apply further cuts to arrive at a final `best sample' that contains our seven strongest ghost candidates. A further five objects show evidence for a ghost feature that is almost strong enough to merit inclusion in our best sample. Despite its limited size, our best sample more than doubles the number of known BAL QSOs with clear ghost signatures and should make an excellent basis for detailed follow-up studies.

M. North; C. Knigge; M. Goad

2005-11-04

100

Spectral line shape of resonant four-wave mixing induced by broad-bandwidth lasers  

NASA Astrophysics Data System (ADS)

We present a theoretical and experimental study of the line shape of resonant four-wave mixing induced by broad-bandwidth laser radiation that revises the theory of Meacher, Smith, Ewart, and Cooper (MSEC) [Phys. Rev. A 46, 2718 (1992)]. We adopt the same method as MSEC but correct for an invalid integral used to average over the distribution of atomic velocities. The revised theory predicts a Voigt line shape composed of a homogeneous, Lorentzian component, defined by the collisional rate ?, and an inhomogeneous, Doppler component, which is a squared Gaussian. The width of the inhomogeneous component is reduced by a factor of ?2 compared to the simple Doppler width predicted by MSEC. In the limit of dominant Doppler broadening, the width of the homogeneous component is predicted to be 4?, whereas in the limit of dominant homogeneous broadening, the predicted width is 2?. An experimental measurement is reported of the line shape of the four-wave-mixing signal using a broad-bandwidth, ``modeless,'' laser resonant with the Q1(6) line of the A 2?-X 2?(0,0) system of the hydroxyl radical. The measured widths of the Voigt components were found to be consistent with the predictions of the revised theory.

Smith, P. G. R.; Ewart, P.

1996-09-01

101

Inconsistencies of the photoionized model for the broad line region in the Seyfert galaxy NGC 7469  

NASA Astrophysics Data System (ADS)

We present a study of ultraviolet and optical spectra of the active galaxy NGC 7469 taken as part of the International AGN Watch database. We have measured the CIV/L?, L?/H? and H?/H? line ratios across the line profiles. The modeling of the observed line ratios has been done with the photoionization code CLOUDY in two variants, with and without taking into account the turbulence in the Broad Line Region (BLR).The comparison of the observed and theoretical emission shows that there are problems with both variants. The observed line ratios can be accounted for by two systems of clouds without turbulence. One corresponds to the high-ionization line (HIL) zone with an electron density n_{e} ? 10^{9-11} cm^{-3}. It is presumably located above the accretion disk. The other system corresponds to the low-ionization line (LIL) zone which is probably the inner part of the accretion disk and which has a high electron density, n_{e}?10^{12.5 - 13} cm^{-3}

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

102

Discovery of a Classic FR-II Broad Absorption Line Quasar from the FIRST Survey  

E-print Network

We have discovered a remarkable quasar, FIRST J101614.3+520916, whose optical spectrum shows unambiguous broad absorption features while its double-lobed radio morphology and luminosity clearly indicate a classic Fanaroff-Riley Type II radio source. Its radio luminosity places it at the extreme of the recently established class of radio-loud broad absorption line quasars (Becker et al. 1997, 2000; Brotherton et al. 1998). Because of its hybrid nature, we speculate that FIRST J101614.3+520916 is a typical FR-II quasar which has been rejuvenated as a broad absorption line (BAL) quasar with a Compact Steep Spectrum core. The direction of the jet axis of FIRST J101614.3+520916 can be estimated from its radio structure and optical brightness, indicating that we are viewing the system at a viewing angle of > 40 degrees. The position angles of the radio jet and optical polarization are not well-aligned, differing by 20 to 30 degrees. When combined with the evidence presented by Becker et al. (2000) for a sample of 29 BAL quasars showing that at least some BAL quasars are viewed along the jet axis, the implication is that no preferred viewing orientation is necessary to observe BAL systems in a quasar's spectrum. This, and the probable young nature of compact steep spectrum sources, leads naturally to the alternate hypothesis that BALs are an early stage in the lives of quasars.

Michael D. Gregg; Robert H. Becker; Michael S. Brotherton; Sally A. Laurent-Muehleisen; Mark Lacy; Richard L. White

2000-06-26

103

The effects of electron scattering opacity in the broad emission-line regions of quasars  

NASA Technical Reports Server (NTRS)

It is demonstrated that three observational puzzles in quasars, nearly symmetric Lyman-alpha profiles, weakly asymmetric C IV 1549 A, and offsets between the peaks of these high ionization lines and the systematic velocity, can all be explained by the standard model of the physical state of the broad-line region with the addition of the simplest possible kinematics. Electron scattering in the intercloud medium is the essential ingredient that had been previously neglected. It is shown that the profiles depend at least as sensitively on the run of physical conditions as on the velocity law. Approximate analytic representations of the line emissivities based on detailed photoionization models are used to describe that dependence.

Kallman, T. R.; Krolik, J. H.

1986-01-01

104

Two cases of culture proven Mycobacterium tuberculosis presenting with a broad-complex tachycardia and non-caseating granulomas  

PubMed Central

Tuberculosis is a leading cause of death worldwide. It affects pulmonary and extra-pulmonary sites with a multitude of differing presentations. In this report, we describe two cases in which TB causes myopericarditis and presents with a broad-complex tachycardia that did not respond typically to standard anti-arrhythmic therapy; a very rare presentation with limited description in the literature. Both patients required extensive investigation culminating in identifying lymph nodes amenable to biopsy under endobronchial ultrasound guidance. It was not until both patients received anti-tuberculous chemotherapy alongside anti-arrhythmic management that any improvement to their condition was witnessed. Therefore, we recommend that the clinician should have a high index of suspicion for TB in any patient presenting with a broad-complex tachycardia that is not responding to standard first line management, especially if the patient is from a high risk background. We recommend an active diagnostic pursuit, and lymph node biopsy under endobronchial ultrasound guidance.

Farah, Z.; Beasley, V.E.; Berry, M.; Coker, R.K.; Kon, O.M.

2014-01-01

105

Physical Properties Of The Broad Line Region In Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

One of the most intriguing objects in the Universe are active galactic nuclei (AGN), being the brightest and the most distant objects. The most accepted scenario of the structure of AGN is the one in which AGN are powered by the accretion of matter from the host galaxy on to super-massive black hole. One of the ways to study the inner emitting region of an AGN, one that is closest to the black hole, is by analyzing its broad emission lines (BELs). These lines originate in the broad line region (BLR), which physics is still not fully understood. In order to probe the physical properties of the emitting plasma in the BLR we analyze the ratios of the following BELs: the hydrogen Balmer lines (Ha to He) and the helium lines from two subsequent ionization levels (He II ?4686 and He I ?5876). We used two samples of the BELs, one obtained from the spectral synthesis photoionization code and the other taken from the Sloan Digital Sky Survey database. We investigate the above BELs in order to find conditions in the BLR where so-called Boltzmann-plot (BP) method might be applicable. For these special cases, we found relations between the average temperature, hydrogen density and He II/He I line ratio. We estimated the physical parameters in the BLR, the average temperature and hydrogen density, to be in the range Tav=5700-18700 K and nH=10^8.2 -10^11.1 cm-3. Moreover, we found relations between the BLR physical parameters and gas velocities, indicating that there should be some connection between the physics and kinematics in the BLR.

Ilic, D.; Popovic, L.; Ciroi, S.; Mura, G. L.; Rafanelli, P.

2010-07-01

106

Origin of the Seemingly Broad Iron-Line Spectral Feature in Seyfert Galaxies  

NASA Astrophysics Data System (ADS)

A seemingly broad iron K- and/or L-line spectral feature is observed from MCG-6-30-15, 1H0707-495 and other Seyfert galaxies. Some interpret these spectral features as due to extremely relativistic distortion of iron emission lines from the innermost region of the accretion disk. We show that these characteristic spectral features are more simply explained by ``double-partial covering'' of two absorption layers with the same covering fraction such that the thick and low-ionized layer is responsible for the iron K-edge and the thin and high-ionized layer is responsible for the iron L-edge. Most observed spectral variation below a time-scale of a day is caused by change of the partial covering fraction, while the X-ray source luminosity and the spectral shape are not significantly variable. We show that this ``Variable Partial Covering model" (Miyakawa, Ebisawa and Inoue 2012) is successful to explain spectral variation and the seemingly broad iron-line structures in ~20 Seyfert 1 galaxies including MCG-6-30-15 and 1H0707-495. Variation of the partial covering fraction causes such an anti-correlation between the direct component and the transmitted component that cancels each other at the iron K-edge. This explains the significantly small fractional variations in the iron K-energy band, a well-known observational fact in Seyfert galaxies.

Ebisawa, K.; Mizumoto, M.; Sameshima, H.; Iso, N.; Miyakawa, T.; Inoue, H.

2014-07-01

107

Evidence for Broad-Line Region Outflows and Their Impact on Black Hole Mass Measurements  

NASA Astrophysics Data System (ADS)

Recent velocity-resolved reverberation mapping results have shown indications of possible outflowing gas from the H? emitting region of the broad-line region (BLR) in NGC 3227 (Denney et al. 2009, 2010). We show a preliminary velocity-delay map (VDM) from these data that suggests the 2D gas motions could not be fully and accurately interpreted from the 1D velocity-resolved reverberation signal. From the VDM, an outflow component to the emission remains possible but appears to be in addition to an underlying, disk-like BLR structure consistent in size with the measured reverberation lag. The black hole (BH) mass derived from this data is therefore secure from any uncertainties possibly derived from gravitationally unbound gas contributing to the emission. Additionally, we demonstrate that BLR emission from the C IV ?1549 broad emission line can reliably be used as a virial BH mass estimator. The presence of self-absorption, blueshifts, and asymmetries observed in C IV, and possibly connected with outflows, has raised questions in the literature regarding the reliability of using this line for mass estimates. However, our new results (Assef et al. 2011) show that C IV-based masses are in agreement with those of H? when (1) data quality is a priority and (2) a color-correction is applied to the luminosity used to compute the mass estimates.

Denney, K. D.; Assef, R. J.; Horne, K.; Peterson, B. M.; Vestergaard, M.

2012-08-01

108

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

109

Optical Monitoring of the Broad-line Radio Galaxy 3C 390.3  

NASA Astrophysics Data System (ADS)

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?, H?, H?, and for the helium line He II?4686, as well as g-band fluxes and the optical active galactic nucleus (AGN) continuum at ? = 5100 Å. The g-band fluxes and the optical AGN continuum vary simultaneously within the uncertainties, ?cent = (0.2 ± 1.1) days. We find that the emission-line variations are delayed with respect to the variable g-band continuum by ?(H?) = 56.3+2.4 - 6.6 days, ?(H?) = 44.3+3.0 - 3.3 days, ?(H?) = 58.1+4.3 - 6.1 days, and ?(He II 4686) = 22.3+6.5 - 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? and H? and the separation of the blue and red peaks in the broad double-peaked profiles in their rms spectra, we determine M vir bh = 1.77+0.29 - 0.31 × 108 M ? and using ?line of the rms spectra M vir bh = 2.60+0.23 - 0.31 × 108 M ? 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 bh = 0.86+0.19 - 0.18 × 109 M ? (peak separation) and M bh = 1.26+0.21 - 0.16 × 109 M ? (?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 edd/L bol = 0.02, follows the same AGN radius-luminosity relation as radio-quiet AGNs. Based on observations collected at the MDM Observatory.

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.

2012-09-01

110

Simulations of the Broad Line Region of NGC 5548 with Cloudy Code: Temperature Determination  

NASA Astrophysics Data System (ADS)

In this paper an analysis of the physical properties of the Broad Line Region (BLR) of the active galaxy NGC 5548 is presented. Using the photoionization code CLOUDY and the measurements of Peterson et al. (2002), the physical conditions of the BLR are simulated and the BLR temperature is obtained. This temperature was compared to the temperature estimated with the Boltzmann-Plot (BP) method (Popovi? et al. 2007). It was shown that the measured variability in the BLR temperature could be due to the change in the hydrogen density.

Ilic, D.

2007-12-01

111

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

112

Off-axis irradiation and the polarization of broad emission lines in active galactic nuclei  

NASA Astrophysics Data System (ADS)

The STOKES Monte Carlo radiative transfer code has been extended to model the velocity dependence of the polarization of emission lines. We use STOKES to present improved modeling of the velocity-dependent polarization of broad emission lines in active galactic nuclei. We confirm that off-axis continuum emission can produce observed velocity dependencies of both the degree and position angle of polarization. The characteristic features are a dip in the percentage polarization and an S-shaped swing in the position angle of the polarization across the line profile. Some differences between our STOKES results and previous modeling of polarization due to off-axis emission are noted. In particular we find that the presence of an offset between the maximum in line flux and the dip in the percentage of polarization or the central velocity of the swing in position angle does not necessarily imply that the scattering material is moving radially. Our model is an alternative scenario to the equatorial scattering disk described by Smith et al. (2005). We discuss strategies to discriminate between both interpretations and to constrain their relative contributions to the observed velocity-resolved line and polarization.

Goosmann, René W.; Martin Gaskell, C.; Marin, Frédéric

2014-10-01

113

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

NASA Technical Reports Server (NTRS)

We present unambiguous evidence for a parsec scale wind in the Broad-Line Radio Galaxy (BLRG) 3C 382, the first radio-loud AGN whereby an outflow has been measured with X-ray grating spectroscopy. A 118 ks Chandra grating (HETG) observation of 3C 382 has revealed the presence of several high ionization absorption lines in the soft X-ray band, from Fe, Ne, Mg and Si. The absorption lines are blue-shifted with respect to the systemic velocity of 3C 382 by -840+/-60 km/s and are resolved by Chandra with a velocity width of sigma = 340+/-70 km/s. The outflow appears to originate from a single zone of gas of column density N(sub H) = 1.3 x 10(exp 21)/sq cm and ionization parameter log(E/erg/cm/s) = 2.45. From the above measurements we calculate that the outflow is observed on parsec scales, within the likely range from 10-1000 pc, i.e., consistent with an origin in the Narrow Line Region. Finally we also discuss the possibility of a much faster (0.1c) outflow component, based on a blue-shifted iron K(alpha) emission line in the Suzaku observation of 3C 382, which could have an origin in an accretion disk wind.

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

2009-01-01

114

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

NASA Astrophysics Data System (ADS)

We present a deep (~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 NH=5×1023 cm-2. (3) The absorber does not cover the source completely; the covering fraction is ~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 ?~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, S.; Matt, G.; Green, P. J.; Elvis, M.; Singh, K. P.

2001-04-01

115

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

116

MEASUREMENT OF THE BROAD-LINE REGION SIZE IN A LUMINOUS MACHO QUASAR  

SciTech Connect

We measure the broad emission line region (BLR) size of a luminous, L {approx} 10{sup 47} erg s{sup -1}, high-z quasar using broadband photometric reverberation mapping. To this end, we analyze {approx}7.5 years of photometric data for MACHO 13.6805.324 (z {approx_equal} 1.72) in the B and R MACHO bands and find a time delay of 180 {+-} 40 days in the rest frame of the object. Given the spectral-variability properties of high-z quasars, we associate this lag with the rest-UV iron emission blends. Our findings are consistent with a simple extrapolation of the BLR size-luminosity relation in local active galactic nuclei to the more luminous, high-z quasar population. Long-term spectroscopic monitoring of MACHO 13.6805.324 may be able to directly measure the line-to-continuum time delay and test our findings.

Chelouche, Doron [Department of Physics, Faculty of Natural Sciences, University of Haifa, Haifa 31905 (Israel); Daniel, Eliran; Kaspi, Shai, E-mail: doron@sci.haifa.ac.il, E-mail: shai@wise.tau.ac.il, E-mail: elirandviv@gmail.com [School of Physics and Astronomy and the Wise Observatory, Tel-Aviv University, Tel-Aviv 69978 (Israel)

2012-05-10

117

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

118

Investigating the radio-loud phase of broad absorption line quasars  

NASA Astrophysics Data System (ADS)

Context. Broad absorption lines (BALs) are present in the spectra of ~20% of quasars (QSOs); this indicates fast outflows (up to 0.2c) that intercept the observer's line of sight. These QSOs can be distinguished again into radio-loud (RL) BAL QSOs and radio-quiet (RQ) BAL QSOs. The first are very rare, even four times less common than RQ BAL QSOs. The reason for this is still unclear and leaves open questions about the nature of the BAL-producing outflows and their connection with the radio jet. Aims: We explored the spectroscopic characteristics of RL and RQ BAL QSOs with the aim to find a possible explanation for the rarity of RL BAL QSOs. Methods: We identified two samples of genuine BAL QSOs from SDSS optical spectra, one RL and one RQ, in a suitable redshift interval (2.5 < z < 3.5) that allowed us to observe the Mg ii and H? emission lines in the adjacent near-infrared (NIR) band. We collected NIR spectra of the two samples using the Telescopio Nazionale Galileo (TNG, Canary Islands). By using relations known in the literature, we estimated the black-hole mass, the broad-line region radius, and the Eddington ratio of our objects and compared the two samples. Results: We found no statistically significant differences from comparing the distributions of the cited physical quantities. This indicates that they have similar geometries, accretion rates, and central black-hole masses, regardless of whether the radio-emitting jet is present or not. Conclusions: These results show that the central engine of BAL QSOs has the same physical properties with and without a radio jet. The reasons for the rarity of RL BAL QSOs must reside in different environmental or evolutionary variables. Figure 3 is available in electronic form at http://www.aanda.org

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

2014-09-01

119

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

120

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

121

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

122

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

E-print Network

We investigate the possibility of an intrinsic Baldwin Effect (i.e.,nonlinear emission-line response to continuum variations) in the broad H-beta emission line of the active galaxy NGC 5548 using cross-correlation techniques to remove light travel-time effects from the data. We find a nonlinear relationship between the H-beta 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.

Karoline M. Gilbert; Bradley M. Peterson

2002-12-17

123

UV spectral diagnostics for low redshift quasars: estimating physical conditions and radius of the Broad Line Region  

E-print Network

The UV spectral range (1100 - 3000 A) contains the strongest resonance lines observed in active galactic nuclei (AGN). Analysis of UV line intensity ratios and profile shapes in quasar spectra provide diagnostics of physical and dynamical conditions in the broad line emitting region. This paper discusses properties of UV lines in type-1 AGN spectra, and how they lead an estimate of ionizing photon flux, chemical abundances, radius of the broad line emitting region and central black hole mass. These estimates are meaningfully contextualised through the 4D "eigenvector-1" (4DE1) formalism.

Marziani, P; Negrete, C A; Dultzin, D; Del Olmo, A; Carballo, M A Martínez; Zwitter, T; Bachev, R

2014-01-01

124

A simultaneous XMM-Newton and BeppoSAX observation of the archetypal broad line Seyfert 1 galaxy NGC 5548  

NASA Astrophysics Data System (ADS)

We report the spectral analysis of a long XMM-Newton observation of the well-studied, moderate luminosity broad line Seyfert 1 galaxy NGC 5548. The source was at an historically average brightness and we find the hard (3-10 keV) spectrum can be well fitted by a power law of photon index ?~ 1.75, together with reflection. The only feature in the hard X-ray spectrum is a narrow emission line near 6.4 keV, with an equivalent width of ~60 eV. The energy and strength of this line are consistent with fluorescence from `neutral' iron distant from the central continuum source. We find no evidence for a broad Fe K line, with an upper limit well below previous reports, suggesting the inner accretion disc is now absent or highly ionized. The addition of simultaneous BeppoSAX data allows the analysis to be extended to 200 keV, yielding important constraints on the total reflection. Extrapolation of the hard X-ray power law down to 0.3 keV shows a clear `soft excess' below ~0.7 keV. After due allowance for the effects of a complex warm absorber, measured with the XMM-Newton RGS, we find that the soft excess is better described as a smooth upward curvature in the continuum flux below ~2 keV. The soft excess can be modelled either by Comptonized thermal emission or by enhanced reflection from the surface of a highly ionized disc.

Pounds, K. A.; Reeves, J. N.; Page, K. L.; Edelson, R.; Matt, G.; Perola, G. C.

2003-05-01

125

SN 2009bb: A Peculiar Broad-lined Type Ic Supernova  

NASA Astrophysics Data System (ADS)

Ultraviolet, optical, and near-infrared photometry and optical spectroscopy of the broad-lined Type Ic supernova (SN) 2009bb are presented, following the flux evolution from -10 to +285 days past B-band maximum. Thanks to the very early discovery, it is possible to place tight constraints on the SN explosion epoch. The expansion velocities measured from near maximum spectra are found to be only slightly smaller than those measured from spectra of the prototype broad-lined SN 1998bw associated with GRB 980425. Fitting an analytical model to the pseudobolometric light curve of SN 2009bb suggests that 4.1 ± 1.9 M sun of material was ejected with 0.22 ± 0.06 M sun of it being 56Ni. The resulting kinetic energy is 1.8 ± 0.7 × 1052 erg. This, together with an absolute peak magnitude of M B = -18.36 ± 0.44, places SN 2009bb on the energetic and luminous end of the broad-lined Type Ic (SN Ic) sequence. Detection of helium in the early time optical spectra accompanied with strong radio emission and high metallicity of its environment makes SN 2009bb a peculiar object. Similar to the case for gamma-ray bursts (GRBs), we find that the bulk explosion parameters of SN 2009bb cannot account for the copious energy coupled to relativistic ejecta, and conclude that another energy reservoir (a central engine) is required to power the radio emission. Nevertheless, the analysis of the SN 2009bb nebular spectrum suggests that the failed GRB detection is not imputable to a large angle between the line-of-sight and the GRB beamed radiation. Therefore, if a GRB was produced during the SN 2009bb explosion, it was below the threshold of the current generation of ?-ray instruments. This paper includes data gathered with the 6.5-m Magellan Telescopes located at Las Campanas Observatory, Chile. Based on observations obtained at the Gemini Observatory, Cerro Pachon, Chile (Gemini Programs GS-2009A-Q-17 and GS-2009A-Q-43).

Pignata, Giuliano; Stritzinger, Maximilian; Soderberg, Alicia; Mazzali, Paolo; Phillips, M. M.; Morrell, Nidia; Anderson, J. P.; Boldt, Luis; Campillay, Abdo; Contreras, Carlos; Folatelli, Gastón; Förster, Francisco; González, Sergio; Hamuy, Mario; Krzeminski, Wojtek; Maza, José; Roth, Miguel; Salgado, Francisco; Levesque, Emily M.; Rest, Armin; Crain, J. Adam; Foster, Andrew C.; Haislip, Joshua B.; Ivarsen, Kevin M.; LaCluyze, Aaron P.; Nysewander, Melissa C.; Reichart, Daniel E.

2011-02-01

126

Constraining UV Continuum Slopes of Active Galactic Nuclei With CLOUDY Models of Broad Line Region EUV Emission Lines  

E-print Network

Understanding the composition and structure of the broad-line region (BLR) of active galactic nuclei (AGN) is important for answering many outstanding questions in supermassive black hole evolution, galaxy evolution, and ionization of the intergalactic medium. We used single-epoch UV spectra from the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope to measure EUV emission-line fluxes from four individual AGN with $0.49 \\le z \\le 0.64$, two AGN with $0.32 \\le z \\le 0.40$, and a composite of 159 AGN. With the Cloudy photoionization code, we calculated emission-line fluxes from BLR clouds with a range of density, hydrogen ionizing flux and incident continuum spectral indices. The photoionization grids were fit to the observations using single-component and locally optimally emitting cloud (LOC) models. The LOC models provide good fits to the measured fluxes, while the single-component models do not. The UV spectral indices preferred by our LOC models are consistent with those measured from COS spe...

Moloney, Joshua

2014-01-01

127

Weak Reprocessed Features in the Broad-Line Radio Galaxy 3C 382  

NASA Astrophysics Data System (ADS)

We present a detailed X-ray study of the broad-line radio galaxy 3C 382, observed with the BeppoSAX satellite in a very bright state. The continuum emission is well modeled with a power law that steepens at high energies, with an e-folding energy of ~120 keV. At soft energies a clear excess of emission is detected, which cannot be explained solely by the extended thermal halo seen in a ROSAT/HRI image. A second, more intense soft X-ray component, possibly related to an accretion disk, is required by the data. Both a reflection component (?/2?=0.3) and an iron line (EW~50) are detected at levels much weaker than in Seyfert galaxies, suggesting a common origin. Combining our measurements with results from the literature we find that the iron line has remained approximately constant over 9 yr while the continuum varied by a factor of 5. Thus, the fluorescent gas does not respond promptly to the variations of the X-ray continuum, suggesting that the reprocessing site is located away from the X-ray continuum, likely at parsec distances. While the continuum shape indicates that X-rays derive from a thermal Comptonization process, the weakness of other spectral features implies that either the upper layers of the optically thick accretion disk are completely ionized or the corona above the disk is outflowing with mildly relativistic velocity.

Grandi, Paola; Maraschi, Laura; Urry, C. Megan; Matt, Giorgio

2001-07-01

128

The Broad Line Region in NGC 4051: An Inflow Illuminated by a 105 K Accretion Disk  

NASA Astrophysics Data System (ADS)

Adopting a spherically symmetric steady-state ballistic inflow as the kinematic model for the gas distribution responsible for producing the H? emission line, and a central black hole (BH) mass of 1.7 × 106 M ? determined from prior reverberation mapping, leads to the following dimensions for the size of the broad line region (BLR) in NGC 4051 an inner radius ~3 lt-day and a lower limit to the outer radius ~475 lt-day. Thus, the previously determined reverberation size for the BLR marks just the inner radius of a much larger volume of ionized gas. The number of ionizing photons required to sustain the H? emission line luminosity exceeds the number observed to be available from the central active galactic nucleus (AGN) by a factor of 3-4. Such a large ionizing deficit can be reconciled if the BLR is ionized by a 105 K accretion disk that is hidden from direct view by the high opacity of intervening H gas. A new definition is introduced for the ionization parameter that acknowledges the fact that H opacity significantly attenuates the flux of ionizing photons in the large, partially ionized nebula surrounding the AGN. Collectively, the results have important implications for BH masses estimated using reverberation radii and the structure of the BLR inferred from velocity-delay maps.

Devereux, Nick; Heaton, Emily

2013-08-01

129

FR-II Broad Absorption Line Quasars and the Life Cycle of Quasars  

SciTech Connect

By combining the Sloan Digitized Sky Survey Third Data Release quasar list with the VLA FIRST survey, we have identified five objects having both broad absorption lines in their optical spectra and FR-II radio morphologies. We identify an additional example of this class from the FIRST Bright Quasar Survey, J1408+3054. Including the original FR-II-BAL object, J1016+5209, brings the number of such objects to eight. These quasars are relatively rare; finding this small handful has required the 45,000-large quasar sample of SDSS. The FR-II-BAL quasars exhibit a significant anti-correlation between radio-loudness and the strength of the BAL features. This is easily accounted for by the evolutionary picture in which quasars emerge from cocoons of BAL-producing material which stifle the development of radio jets and lobes. There is no such simple explanation for the observed properties of FR-II-BALs in the unification-by-orientation model of quasars. The rarity of the FR-II-BAL class implies that the two phases do not coexist for very long in a single quasar, perhaps less than 10{sup 5} years, with the combined FR-II, high ionization broad absorption phase being even shorter by another factor of 10 or more.

Gregg, M D; Becker, R H; de Vries, W

2006-01-05

130

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

131

Spectropolarimetry of PKS 0040-005 and the orientation of broad absorption line quasars  

NASA Astrophysics Data System (ADS)

We have used the Very Large Telescope (VLT) to obtain spectropolarimetry of the radio-loud, double-lobed broad absorption line (BAL) quasar PKS 0040-005. We find that the optical continuum of PKS 0040-005 is intrinsically polarized at 0.7 per cent with an electric vector position angle nearly parallel to that of the large-scale radio axis. This result is naturally explained in terms of an equatorial scattering region seen at a small inclination, building a strong case that the BAL outflow is not equatorial. In conjunction with other recent results concerning BAL quasars, the era of simply characterizing these sources as `edge-on' is over. Based on observations collected at the European Southern Observatory, Paranal, project 71.B-0121(A). E-mail: mbrother@uwyo.edu (MSB); cdbreuc@eso.org (CDB); schaefjj@ufl.edu (JJS) ‡ ESO Visitor.

Brotherton, M. S.; De Breuck, C.; Schaefer, J. J.

2006-10-01

132

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

133

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

134

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

135

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

136

Results from monitoring the broad-line radio galaxy 3C 390.3  

NASA Technical Reports Server (NTRS)

The broad line radio galaxy 3C 390.3 was observed in a multiwavelength monitoring campaign by the Rosat high resolution imager (HRI), the International Ultraviolet Explorer and ground-based optical, infrared and and radio observations. The preliminary results from the campaign are reported, with emphasis on the X-ray observations. A large amplitude variability is observed. The light curve is dominated by a flare near JD 2449800, characterized by a doubling time scale of 9 days and a general increase in flux after the flare. The optical R and I band light curves show a general increase in flux. Spectra from the Advanced Satellite for Cosmology and Astrophysics (ASCA) obtained before and after the flare can be described by an absorbed power law.

Leighly, K, M.; Dietrich, M.; Waltman, E.; Edelson, R.; George, I.; Malkan, M.; Matsuoka, M.; Mushotzky, R.; Peterson, B. M.

1996-01-01

137

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

138

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

139

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

140

Final verdict from XMM-Newton: the X-ray obscured Seyfert galaxy NGC 5506 has a broad Fe K? line  

NASA Astrophysics Data System (ADS)

We present the first unambiguous evidence of a broad (Gaussian width ~330 eV) component of the iron K? fluorescent emission line in the X-ray obscured narrow-line Seyfert 1 galaxy, NGC 5506. This is the main result of a spectroscopic monitoring campaign on this source, performed with the XMM-Newton observatory between 2001 February and 2009 January. The broad line lacks extreme redward skewness. If modelled with a relativistic component, the profile of the line is consistent with a flat emissivity radial dependence (? ~= 1.9). The disc inclination (~=40°) is nominally larger than typically observed in unobscured active galactic nuclei (AGNs), in agreement with most measurements of broadened iron lines in Seyfert 2 galaxies. The quality of the data allows us to decompose the full iron emission-line complex, and to study its long-term (time-scales of weeks to yr) variability pattern. The intensity of the neutral and narrow iron K? core remains constant during the monitoring campaign. This indicates that the optically thick gas responsible for the non-relativistic reprocessing of the primary AGN continuum in NGC 5506 is probably located in the torus rather than in the optical broad-line region.

Guainazzi, M.; Bianchi, S.; Matt, G.; Dadina, M.; Kaastra, J.; Malzac, J.; Risaliti, G.

2010-08-01

141

A Revised Broad-line Region Radius and Black Hole Mass for the Narrow-line Seyfert 1 NGC 4051  

NASA Astrophysics Data System (ADS)

We present the first results from a high sampling rate, multimonth reverberation mapping campaign undertaken primarily at MDM Observatory with supporting observations from telescopes around the world. The primary goal of this campaign was to obtain either new or improved H? reverberation lag measurements for several relatively low luminosity active galactic nuclei (AGNs). We feature results for NGC 4051 here because, until now, this object has been a significant outlier from AGN scaling relationships, e.g., it was previously a ~2-3? outlier on the relationship between the broad-line region (BLR) radius and the optical continuum luminosity—the R BLR-L relationship. Our new measurements of the lag time between variations in the continuum and H? emission line made from spectroscopic monitoring of NGC 4051 lead to a measured BLR radius of R BLR = 1.87+0.54 -0.50 light days and black hole mass of M BH = (1.73+0.55 -0.52) × 106 M sun. This radius is consistent with that expected from the R BLR-L relationship, based on the present luminosity of NGC 4051 and the most current calibration of the relation by Bentz et al.. We also present a preliminary look at velocity-resolved H? light curves and time delay measurements, although we are unable to reconstruct an unambiguous velocity-resolved reverberation signal.

Denney, K. D.; Watson, L. C.; Peterson, B. M.; Pogge, R. W.; Atlee, D. W.; Bentz, M. C.; Bird, J. C.; Brokofsky, D. J.; Comins, M. L.; Dietrich, M.; Doroshenko, V. T.; Eastman, J. D.; Efimov, Y. S.; Gaskell, C. M.; Hedrick, C. H.; Klimanov, S. A.; Klimek, E. S.; Kruse, A. K.; Lamb, J. B.; Leighly, K.; Minezaki, T.; Nazarov, S. V.; Petersen, E. A.; Peterson, P.; Poindexter, S.; Schlesinger, Y.; Sakata, K. J.; Sergeev, S. G.; Tobin, J. J.; Unterborn, C.; Vestergaard, M.; Watkins, A. E.; Yoshii, Y.

2009-09-01

142

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

SciTech Connect

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

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

2012-10-01

143

A New Method to Obtain the Broad Line Region Size of High Redshift Quasars  

NASA Astrophysics Data System (ADS)

We present high signal-to-noise ratio UV spectra for eight quasars at z ~ 3 obtained with Very Large Telescope/FORS. The spectra enable us to analyze in detail the strong and weak emission features in the rest frame range 1300-2000 Å of each source (C III] ?1909, Si III] ?1892, Al III ?1860, Si II ?1814, C IV ?1549 and blended Si IV ?1397+O IV] ?1402). The flux ratios Al III ?1860/Si III] ?1892, C IV ?1549/Al III ?1860, Si IV ?1397+O IV] ?1402/Si III] ?1892 and Si IV ?1397+O IV] ?1402/C IV ?1549 strongly constrain ionizing photon flux and metallicity through the use of diagnostic maps built from CLOUDY simulations. The radius of the broad line region is then derived from the ionizing photon flux applying the definition of the ionization parameter. The r BLR estimate and the width of a virial component isolated in prominent UV lines yields an estimate of black hole mass. We compare our results with previous estimates obtained from the r BLR-luminosity correlation customarily employed to estimate the black hole masses of high redshift quasars. Based on observations made with ESO Telescopes at Paranal Observatory under program ID 078.B-0109(A).

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

2014-10-01

144

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

NASA Astrophysics Data System (ADS)

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

Pu, Xingting

2013-06-01

145

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

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

146

A CENSUS OF BROAD-LINE ACTIVE GALACTIC NUCLEI IN NEARBY GALAXIES: COEVAL STAR FORMATION AND RAPID BLACK HOLE GROWTH  

SciTech Connect

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

Trump, Jonathan R.; Fang, Jerome J.; Faber, S. M.; Koo, David C.; Kocevski, Dale D. [University of California Observatories/Lick Observatory and Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)] [University of California Observatories/Lick Observatory and Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Hsu, Alexander D. [The Harker School, 500 Saratoga Avenue, San Jose, CA 95129 (United States)] [The Harker School, 500 Saratoga Avenue, San Jose, CA 95129 (United States)

2013-02-15

147

EVOLUTION AND HYDRODYNAMICS OF THE VERY BROAD X-RAY LINE EMISSION IN SN 1987A  

SciTech Connect

Observations of SN 1987A by the Chandra High Energy Transmission Grating (HETG) in 1999 and the XMM-Newton Reflection Grating Spectrometer (RGS) in 2003 show very broad (v-b) lines with a full width at half-maximum (FWHM) of order 10{sup 4} km s{sup -1}; at these times the blast wave (BW) was primarily interacting with the H II region around the progenitor. Since then, the X-ray emission has been increasingly dominated by narrower components as the BW encounters dense equatorial ring (ER) material. Even so, continuing v-b emission is seen in the grating spectra suggesting that the interaction with H II region material is ongoing. Based on the deep HETG 2007 and 2011 data sets, and confirmed by RGS and other HETG observations, the v-b component has a width of 9300 {+-} 2000 km s{sup -1} FWHM and contributes of order 20% of the current 0.5-2 keV flux. Guided by this result, SN 1987A's X-ray spectra are modeled as the weighted sum of the non-equilibrium-ionization emission from two simple one-dimensional hydrodynamic simulations; this '2 Multiplication-Sign 1D' model reproduces the observed radii, light curves, and spectra with a minimum of free parameters. The interaction with the H II region ({rho}{sub init} Almost-Equal-To 130 amu cm{sup -3}, {+-} 15 Degree-Sign opening angle) produces the very broad emission lines and most of the 3-10 keV flux. Our ER hydrodynamics, admittedly a crude approximation to the multi-D reality, gives ER densities of {approx}10{sup 4} amu cm{sup -3}, requires dense clumps ( Multiplication-Sign 5.5 density enhancement in {approx}30% of the volume), and predicts that the 0.5-2 keV flux will drop at a rate of {approx}17% per year once no new dense ER material is being shocked.

Dewey, D.; Canizares, C. R. [MIT Kavli Institute, Cambridge, MA 02139 (United States); Dwarkadas, V. V. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Haberl, F.; Sturm, R., E-mail: dd@space.mit.edu, E-mail: vikram@oddjob.uchicago.edu [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, Garching D-85748 (Germany)

2012-06-20

148

A REVISED BROAD-LINE REGION RADIUS AND BLACK HOLE MASS FOR THE NARROW-LINE SEYFERT 1 NGC 4051  

SciTech Connect

We present the first results from a high sampling rate, multimonth reverberation mapping campaign undertaken primarily at MDM Observatory with supporting observations from telescopes around the world. The primary goal of this campaign was to obtain either new or improved H{beta} reverberation lag measurements for several relatively low luminosity active galactic nuclei (AGNs). We feature results for NGC 4051 here because, until now, this object has been a significant outlier from AGN scaling relationships, e.g., it was previously a {approx}2-3{sigma} outlier on the relationship between the broad-line region (BLR) radius and the optical continuum luminosity-the R {sub BLR}-L relationship. Our new measurements of the lag time between variations in the continuum and H{beta} emission line made from spectroscopic monitoring of NGC 4051 lead to a measured BLR radius of R{sub BLR} = 1.87{sup +0.54}{sub -0.50} light days and black hole mass of M{sub BH} = (1.73{sup +0.55}{sub -0.52}) x 10{sup 6} M{sub sun}. This radius is consistent with that expected from the R{sub BLR}-L relationship, based on the present luminosity of NGC 4051 and the most current calibration of the relation by Bentz et al.. We also present a preliminary look at velocity-resolved H{beta} light curves and time delay measurements, although we are unable to reconstruct an unambiguous velocity-resolved reverberation signal.

Denney, K. D.; Watson, L. C.; Peterson, B. M. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)], E-mail: denney@astronomy.ohio-state.edu, E-mail: watson@astronomy.ohio-state.edu, E-mail: peterson@astronomy.ohio-state.edu (and others)

2009-09-10

149

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

SciTech Connect

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.; Schneider, D. P. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Hall, P. B. [Department of Physics and Astronomy, York University, 4700 Keele St., Toronto, Ontario, M3J 1P3 (Canada); Anderson, S. F. [Astronomy Department, University of Washington, Seattle, WA 98195 (United States); Hamann, F. [Department of Astronomy, University of Florida, Gainesville, FL 32611-2055 (United States); Lundgren, B. F. [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States); Myers, Adam D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Pâris, I. [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Petitjean, P. [Universite Paris 6, Institut d'Astrophysique de Paris, 75014, Paris (France); Ross, Nicholas P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 92420 (United States); Shen, Yue [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS-51, Cambridge, MA 02138 (United States); York, Don, E-mail: nfilizak@astro.psu.edu [The University of Chicago, Department of Astronomy and Astrophysics, Chicago, IL 60637 (United States)

2013-11-10

150

A variable P v broad absorption line and quasar outflow energetics  

NASA Astrophysics Data System (ADS)

Broad absorption lines (BALs) in quasar spectra identify high-velocity outflows that might exist in all quasars and could play a major role in feedback to galaxy evolution. The viability of BAL outflows as a feedback mechanism depends on their kinetic energies, as derived from the outflow velocities, column densities, and distances from the central quasar. We estimate these quantities for the quasar, Q1413+1143 (redshift ze = 2.56), aided by the first detection of P V ??1118, 1128 BAL variability in a quasar. In particular, P V absorption at velocities where the C IV trough does not reach zero intensity implies that the C IV BAL is saturated and the absorber only partially covers the background continuum source (with characteristic size <0.01 pc). With the assumption of solar abundances, we estimate that the total column density in the BAL outflow is log NH ? 22.3 cm-2. Variability in the P V and saturated C IV BALs strongly disfavours changes in the ionization as the cause of the BAL variability, but supports models with high column density BAL clouds moving across our lines of sight. The observed variability time of 1.6 yr in the quasar rest frame indicates crossing speeds >750 km s-1 and a radial distance from the central black hole of ? 3.5 pc, if the crossing speeds are Keplerian. The total outflow mass is ˜4100 M?, the kinetic energy ˜4 × 1054 erg, and the ratio of the outflow kinetic energy luminosity to the quasar bolometric luminosity is ˜0.02 (at the minimum column density and maximum distance), which might be sufficient for important feedback to the quasar's host galaxy.

Capellupo, D. M.; Hamann, F.; Barlow, T. A.

2014-10-01

151

The correlation between the Doppler factor and broad line region luminosity in blazars  

NASA Astrophysics Data System (ADS)

The disk-jet symbiosis is a fundamental problem in our understanding of the Active Galactic Nuclei (AGN). We explore the relation between the Doppler factors ? of the jet of blazars and their broad line region luminosity L BLR. Since different methods measuring ? might differ substantially, we use data obtained from 3 independent methods and compile 3 samples of sources for each of them, respectively. Two samples consist of blazars, that is, Flat Spectrum Radio Quasars (FSRQs) and BL Lacertae objects (BL Lacs), and the other consists of BL Lacs. ? is one of the most important jet properties and L BLR is thought to be the proxy of the accretion power. Correlation analysis to these samples shows that there exists a significant correlation between ? and L BLR, which supports the idea that the jet powering process is closely linked with the accretion process and provides new evidence for disk-jet connection. Furthermore, the results are consistent with the idea that the Blandford-Znajek mechanism is sufficient for BL Lacs and a hybrid model is needed for FSRQs.

Du, LeiMing; Bai, JinMing

2012-10-01

152

Efficiently computing and deriving topological relation matrices between complex regions with broad boundaries  

NASA Astrophysics Data System (ADS)

The extended 9-intersection matrix is used to formalize topological relations between uncertain regions while it is designed to satisfy the requirements at a concept level, and to deal with the complex regions with broad boundaries (CBBRs) as a whole without considering their hierarchical structures. In contrast to simple regions with broad boundaries, CBBRs have complex hierarchical structures. Therefore, it is necessary to take into account the complex hierarchical structure and to represent the topological relations between all regions in CBBRs as a relation matrix, rather than using the extended 9-intersection matrix to determine topological relations. In this study, a tree model is first used to represent the intrinsic configuration of CBBRs hierarchically. Then, the reasoning tables are presented for deriving topological relations between child, parent and sibling regions from the relations between two given regions in CBBRs. Finally, based on the reasoning, efficient methods are proposed to compute and derive the topological relation matrix. The proposed methods can be incorporated into spatial databases to facilitate geometric-oriented applications.

Du, Shihong; Guo, Luo; Wang, Qiao; Qin, Qimin

153

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

NASA Astrophysics Data System (ADS)

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

Lazarova, Mariana Spasova

154

THE LONG-TERM X-RAY VARIABILITY OF BROAD ABSORPTION LINE QUASARS  

SciTech Connect

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

Saez, C.; Brandt, W. N.; Garmire, G. P. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Gallagher, S. C. [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada); Bauer, F. E. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile)

2012-11-01

155

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

156

X-RAYS FROM A RADIO-LOUD COMPACT BROAD ABSORPTION LINE QUASAR 1045+352 AND THE NATURE OF OUTFLOWS IN RADIO-LOUD BROAD ABSORPTION LINE QUASARS  

SciTech Connect

We present new results on X-ray properties of radio-loud broad absorption line (BAL) quasars and focus on broadband spectral properties of a high-ionization BAL (HiBAL) compact steep spectrum (CSS) radio-loud quasar 1045+352. This HiBAL quasar has a very complex radio morphology indicating either strong interactions between a radio jet and the surrounding interstellar medium or a possible re-start of the jet activity. We detected 1045+352 quasar in a short 5 ksec Chandra ACIS-S observation. We applied theoretical models to explain spectral energy distribution of 1045+352 and argue that non-thermal, inverse-Compton (IC) emission from the innermost parts of the radio jet can account for a large fraction of the observed X-ray emission. In our analysis, we also consider a scenario in which the observed X-ray emission from radio-loud BAL quasars can be a sum of IC jet X-ray emission and optically thin corona X-ray emission. We compiled a sample of radio-loud BAL quasars that were observed in X-rays to date and report no correlation between their X-ray and radio luminosity. However, the radio-loud BAL quasars show a large range of X-ray luminosities and absorption columns. This is consistent with the results obtained earlier for radio-quiet BAL quasars and may indicate an orientation effect in BAL quasars or more complex dependence between X-ray emission, radio emission, and an orientation based on the radio morphology.

Kunert-Bajraszewska, Magdalena; Katarzynski, Krzysztof [Torun Centre for Astronomy, N. Copernicus University, Gagarina 11, 87-100 Torun (Poland); Siemiginowska, Aneta [Harvard Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Janiuk, Agnieszka [N. Copernicus Astronomical Center, Bartycka 18, 00-716 Warsaw (Poland)

2009-11-10

157

Origin of the X-ray Spectral Variation and Seemingly Broad Iron Line Strucuture in the Seyfert Galaxies  

NASA Astrophysics Data System (ADS)

X-ray intensities and spectra of the Seyfert galaxies are known to be variable. Some of the sources have characteristic seemingly broad iron line structure, and their spectral variations are small in the iron line energy band. MCG-6-30-15 is such an archetypal source, and Miyakawa (2011) proposed a "Variable Partial Covering (VPC)" model to explain its continuum spectral variation, seemingly broad iron line structure, and small spectral variation in the iron energy band simultaneously, only due to variation of a single parameter. That single parameter is the "partial covering fraction" to describe the geometrical fraction of the X-ray emitting area covered by the ionized absorbers in the line of sight. The intrinsic X-ray luminosity is hardly variable in this model. We have applied the VPC model to the 27 Seyfert galaxies observed with Suzaku, and found that spectral variations of the 22 sources are successfully explained by this model only varying the partial covering fraction. Intrinsic X-ray luminosities of Seyfert galaxies are not variable, as opposed to what they apparently seem, and gravitationally red-shifted iron line is not necessary. Those ionized absorbing clouds are most likely to be Broad Line Region (BLR) clouds, and we will be able to constrain the BLR structure from X-ray observations.

Ebisawa, Ken; Naoki, Iso

2012-07-01

158

Evolution and Hydrodynamics of the Very-Broad X-ray Line Emission in SN1987A  

E-print Network

Observations of SN 1987A by the Chandra High Energy Transmission Grating (HETG) in 1999 and the XMM-Newton Reflection Grating Spectrometer (RGS) in 2003 show very broad (v-b) lines with a full width at half-maximum (FWHM) ...

Dewey, Dan

159

Radio Properties of Low-Redshift Broad Line Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

The question as to whether the distribution of radio loudness in active galactic nuclei (AGNs) is actually bimodal has been discussed extensively in the literature. Furthermore, there have been claims that radio loudness depends on black hole mass (M BH) and Eddington ratio (L bol/L Edd). We investigate these claims using the low-redshift broad line AGN sample of Greene & Ho, which consists of 8434 objects at z < 0.35 from the Sloan Digital Sky Survey Fourth Data Release (SDSS DR4). We obtained radio fluxes from the Very Large Array Faint Images of the Radio Sky at Twenty-centimeters (FIRST) survey for the SDSS AGN. Out of the 8434 SDSS AGNs, 821 have corresponding observed radio fluxes in the FIRST survey. We calculated the radio-loudness parameter (R) for all objects above the FIRST detection limit (1 mJy), and an upper limit to R for the undetected objects. Using these data, the question of radio bimodality is investigated for different subsets of the total sample. We find no clear demarcation between the radio loud (RL; R > 10) and radio quiet (R < 10) objects, but instead fill in a more radio-intermediate population in a continuous fashion for all subsamples. We find that 4.7% of the AGNs in the flux-limited subsample are RL based on core radio emission alone. We calculate the radio-loud fraction (RLF) as both a function of M BH and L bol/L Edd. The RLF decreases (from 13% to 2%) as L bol/L Edd increases over 2.5 orders of magnitude. The RLF is nearly constant (~5%) over four decades in M BH, except for an increase at M BH > 108 M sun. We find for the FIRST detected subsample that 367 of the RL AGNs have M BH < 108 M sun, a large enough number to indicate that RL AGNs are not a product of only the most massive black holes in the local universe.

Rafter, Stephen E.; Crenshaw, D. Michael; Wiita, Paul J.

2009-01-01

160

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

161

Hour-timescale profile variations in the broad Balmer lines of the Seyfert galaxy Hour-timescale profile variations in the broad Balmer lines of the Seyfert galaxy Markarian 6  

NASA Astrophysics Data System (ADS)

Part of results of the multi-epoch intranight optical spectroscopic monitoring of the Markarian 6 nucleus carried out at the telescopes of 6-m of the Special Astrophysical Observatory (Russia), 2.6-m of the Byurakan Astrophysical Observatory (Armenia) and 2-m of the Tautenburg Observatory (Germany) is presented. Observations were made in 1979, 1986, 1988-1991 and 2007-2009 during a total of 33 nights with an average sampling rate of 4 spectra per night. TV-scanner and long-slit spectrographs equipped with Image Tube and CCD detector arrays were used. Altogether we analyzed 110 H? and 58 H? region spectra to search for intranight variability in the broad hydrogen emission line profiles. The typical spectral resolutions were 4 Å for scanner spectra, 6 Å for photographic spectra, and 5 Å and 10 Å for CCD spectra. The S/N ratio at the continuum level near the H? and H? lines was in the range 15-50. The purpose of the search was to look for the characteristic variability signatures of different kinematical models of the broad emission-line region. We considered the centering and guiding errors which can result in differences between spectra. We found variations in the broad Balmer line difference profiles on time scale of hour with the level of significance of 3.6 ? to 5.0 ?. Variations take the form of narrow, small bumps located at the blue and red sides or only at the blue side of the lines. In the intermediate level of broad line flux, the H? and H? profiles show fine structure. Detected profile changes occurred at the same radial velocity shifts as the details in the fine structure. The variability is at least 2 orders of magnitude more rapid than any observed for broad Balmer line profiles in AGNs that we are aware of in the literature. Discovered extremely rapid line-profile variability may be associated with reverberation effects. Two-sided profile changes may indicate the response of circularly rotating hydrogen clouds in the BLR to a light pulse from a central source. One-sided profile variations may be attributed to a response of a non-disk component: the subarcsec scale region of the jet.

Asatrian, Norayr S.

2014-07-01

162

The link between broad emission line fluctuations and non-thermal emission from the inner AGN jet  

E-print Network

AGN reverberate when the broad emission lines respond to changes of the ionizing thermal continuum emission. Reverberation measurements have been commonly used to estimate the size of the broad-line region (BLR) and the mass of the central black hole. However, reverberation mapping studies have been mostly performed on radio-quiet sources where the contribution of the jet can be neglected. In radio-loud AGN, jets and outflows may affect substantially the relation observed between the ionizing continuum and the line emission. To investigate this relation, we have conducted a series of multiwavelength studies of radio-loud AGN, combining optical spectral line monitoring with regular VLBI observations. Our results suggest that at least a fraction of the broad-line emitting material can be located in a sub-relativistic outflow ionized by non-thermal continuum emission generated in the jet at large distances (> 1pc) from the central engine of AGN. This finding may have a strong impact on black hole mass estimates ...

León-Tavares, J; Lobanov, A; Valtaoja, E; Arshakian, T G

2014-01-01

163

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

SciTech Connect

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

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

2011-09-01

164

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

Microsoft Academic Search

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

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

2005-01-01

165

WISE J233237.05-505643.5: A Double-Peaked Broad-Lined AGN with Spiral-Shaped Radio Morphology  

NASA Technical Reports Server (NTRS)

We present radio continuum mapping, optical imaging and spectroscopy of the newly discovered double-peaked broad-lined AGN WISE J233237.05-505643.5 at redshift z = 0.3447. This source exhibits an FR-I and FR-II hybrid-morphology, characterized by bright core, jet, and Doppler-boosted lobe structures in ATCA 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 year baseline from the AGN component. Gemini-South optical data shows an unusual double-peaked emission-line features: the centroids of the broad-lined components of H-alpha and H-beta are blueshifted with respect to the narrow lines and host galaxy by approximately 3800 km/s. We examine possible cases which involve single or double supermassive black holes in the system, and discuss required future investigations to disentangle the mystery nature of this system.

Tsai, Chao Wei; Jarrett, Thomas 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.

2013-01-01

166

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

167

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

168

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

169

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

170

Variability of broad absorption lines in QSO SDSS J022844.09+000217.0 on multiyear time-scales  

NASA Astrophysics Data System (ADS)

The variability of broad absorption lines is investigated for a broad-absorption-line (BAL) quasar (QSO), SDSS J022844.09+000217.0 (z = 2.719), with 18 Sloan Digital Sky Survey (SDSS)/Baryon Oscillation Spectroscopic Survey (BOSS) spectra covering 4128 d in the observed frame. Using the ratio of the root-mean-square (rms) spectrum to the mean spectrum, the relative flux change of the BAL trough is larger than that of the emission lines and the continuum. Fitting a power-law continuum and the emission-line profiles of C IV ?1549 and Si IV?1399, we calculate the equivalent width (EW) for different epochs, as well as the continuum luminosity and the spectral index. It is found that there is a strong correlation between the BAL-trough EW and the spectral index and a weak negative correlation between the BAL-trough EW and the continuum luminosity. The strong correlation between the BAL-trough EW and the spectral index for this particular QSO suggests that dust is intrinsic to outflows. The weak correlation between the BAL variability and the continuum luminosity for this particular QSO implies that the BAL-trough variation is not dominated by photoionization.

He, Zhi-Cheng; Bian, Wei-Hao; Jiang, Xiao-Lei; Wang, Yue-Feng

2014-09-01

171

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

172

Variability of Soft X-ray Spectral Shape: Narrow-Line Seyfert 1 Galaxies versus Broad-Line Seyfert 1 Galaxies  

Microsoft Academic Search

In order to understand how the soft X-ray spectra vary we present the\\u000aHardness Ratio 1 versus Count Rates (HR1-CTs) correlation of 8 Narrow-line\\u000aSeyfert 1 Galaxies (NLS1s) and 14 Broad-line Seyfert1 Galaxies (BLS1s) obtained\\u000aduring the ROSAT PSPC pointing observations. According to our criteria, six of\\u000athe NLS1s show a positive HR1-CTs correlation, and seven of the BLS1s display

Linpeng Cheng; Jianyan Wei; Yongheng Zhao

2001-01-01

173

Broad-wing molecular lines without internal energy sources. [in interstellar clouds  

NASA Technical Reports Server (NTRS)

The discovery of broad CO wings in four high-latitude molecular clouds which do not have associated internal energy sources is reported. The velocity width of the wings is as much as five times greater than the width of the cloud cores. Neither visible stars brighter than the background population, optical nebulosity, nor IRAS point sources are found at the position of the wings, except for one case with an IRAS source 3 arcmin from the peak position of the wings. The possibility that the wings are the result of conductive interfaces resulting from cold molecular clouds in a hotter ambient medium is examined, and it is concluded that the expected column density of such gas is more than three orders of magnitude smaller than that observed.

Blitz, Leo; Magnani, Loris; Wandel, Amri

1988-01-01

174

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

SciTech Connect

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

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

2010-10-01

175

Single-epoch Black Hole Mass Estimators for Broad-line Active Galactic Nuclei: Recalibrating H? with a New Approach  

NASA Astrophysics Data System (ADS)

Based on an updated H? reverberation mapping (RM) sample of 44 nearby active galactic nuclei (AGNs), we propose a novel approach for black hole (BH) mass estimation using two filtered luminosities computed from single-epoch (SE) AGN spectra around the H? region. We found that the two optimal-filter luminosities extract virial information (size and virial velocity of the broad-line region, BLR) from the spectra, justifying their usage in this empirical BH mass estimator. The major advantages of this new recipe over traditional SE BH mass estimators utilizing continuum luminosity and broad-line width are (1) it has a smaller intrinsic scatter of 0.28 dex calibrated against RM masses, (2) it is extremely simple to use in practice, without any need to decompose the spectrum, and (3) it produces unambiguous and highly repeatable results even with low signal-to-noise spectra. The combination of the two luminosities can also cancel out, to some extent, systematic luminosity errors potentially introduced by uncertainties in distance or flux calibration. In addition, we recalibrated the traditional SE mass estimators using broad H? FWHM and monochromatic continuum luminosity at 5100 Å (L 5100). We found that using the best-fit slopes on FWHM and L 5100 (derived from fitting the BLR radius-luminosity relation and the correlation between rms line dispersion and SE FWHM, respectively) rather than simple assumptions (e.g., 0.5 for L 5100 and 2 for FWHM) leads to more precise SE mass estimates, improving the intrinsic scatter from 0.41 dex to 0.36 dex with respect to the RM masses. We compared different estimators and discussed their applications to the Sloan Digital Sky Survey quasar sample. Due to the limitations of the current RM sample, application of any SE recipe calibrated against RM masses to distant quasars should be treated with caution.

Feng, Hua; Shen, Yue; Li, Hong

2014-10-01

176

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

177

Broad-Line Reverberation in the Kepler-Field Seyfert Galaxy Zw 229-015  

E-print Network

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-beta reverberation mapping, we have carried out nightly observations with the Kast Spectrograph at the Lick 3m telescope during the dark runs from June through December 2010, 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 0.9m 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 2 change in broad H-beta flux. From cross-correlation measurements, we find that the H-beta 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-alpha and H-gamma and find an upper limit to the H-delta lag. Combining the H-beta la...

Barth, A J; Malkan, M A; Filippenko, A V; Li, W; Gorjian, V; Joner, M D; Bennert, V N; Botyanszki, J; Cenko, S B; Childress, M; Choi, J; Comerford, J M; Cucciara, A; da Silva, R; Duchene, G; Fumagalli, M; Ganeshalingam, M; Gates, E L; Gerke, B F; Griffith, C V; Harris, C; Hintz, E G; Hsiao, E; Kandrashoff, M T; Keel, W C; Kirkman, D; Kleiser, I K W; Laney, C D; Lee, J; Lopez, L; Lowe, T B; Moody, J W; Morton, A; Nierenberg, A M; Nugent, P; Pancoast, A; Rex, J; Rich, R M; Silverman, J M; Smith, G H; Sonnenfeld, A; Suzuki, N; Tytler, D; Walsh, J L; Woo, J -H; Yang, Y; Zeisse, C

2011-01-01

178

The Disk Wind Model of the Broad Line Regions in Active Galactic Nuclei and Cataclysmic Variables  

NASA Technical Reports Server (NTRS)

This is the final progress report for our Astrophysics Theory Program (NRA 97-OSS12) grant NAG5-7723. We have made considerable progress on incorporating photoionization calculations with a 2.5D hydrodynamical code to model disk winds in AGNs. Following up on our simultaneous broad band monitoring campaign of the type I Seyfert galaxy NGC 5548, we have investigated the constraints imposed on models of accretion in Seyfert galaxies by their optical, UV, and X-ray spectral energy distributions (SEDs). Using results from thermal Comptonization models that relate the physical properties of the hot inner accretion flow to the thermal reprocessing that occurs in the surrounding colder thin disk, we find that we can constrain the central black hole mass, accretion rate and size scale of the hot central flow. We have applied our model to observations of Seyfert galaxies NGC 3516, NGC 7469 and NGC 5548. Our mass and accretion rate estimates for these objects roughly agree with those found using other methods.

Begelman, Mitchell

2002-01-01

179

Broad-range self-sweeping of a narrow-line self-pulsing Yb-doped fiber laser.  

PubMed

The effect of broad-range (16 nm) self-sweeping of a narrow-line (less than 1 pm) Yb-doped fiber laser has been demonstrated experimentally. It is found that the effect arises from the self-sustained relaxation oscillations. As a result, the sweeping rate increases as square root of the laser power and decreases with increasing cavity length. Based on these results we propose a model describing dynamics of the laser frequency. The model takes into account the effects of gain saturation at the laser transition and spatial hole burning in the self-pulsing regime. PMID:21935130

Lobach, Ivan A; Kablukov, Sergey I; Podivilov, Evgeniy V; Babin, Sergey A

2011-08-29

180

Discovery of ultra-fast outflows in a sample of Broad Line Radio Galaxies observed with Suzaku  

E-print Network

We present the results of a uniform and systematic search for blue-shifted Fe K absorption lines in the X-ray spectra of five bright Broad-Line Radio Galaxies (BLRGs) observed with Suzaku. We detect, for the first time at X-rays in radio-loud AGN, 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 blue-shifted Fe XXV and Fe XXVI K-shell resonance lines implies an origin from highly ionized gas outflowing with mildly relativistic velocities, in the range 0.04-0.15c. A fit with specific photo-ionization models gives ionization parameters in the range log_xi~4-5.6 and column densities of N_H~10^22-10^23 cm^-2. These characteristics are very similar to those of the Ultra-Fast Outflows (UFOs) previously observed in radio-quiet AGN. Their estimated location within ~0.01-0.3pc from the central super-mass...

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

2010-01-01

181

Global trade in dairy products involves complex and con-tentious issues. Viewed broadly from the perspective of  

E-print Network

Global trade in dairy products involves complex and con- tentious issues. Viewed broadly from the perspective of "society," there are large benefits from liberalizing trade. Viewed narrowly from the perspective of dairy producers, liberalized trade is desirable only if it expands exports and reduces imports

Radeloff, Volker C.

182

Transient Superstrong Coronal Lines and Broad Bumps in the Galaxy SDSS J074820.67+471214.3  

NASA Astrophysics Data System (ADS)

Variable superstrong coronal emission lines were observed in the spectrum of one galaxy, SDSS J095209.56+214313.3, and their enigmatic origin remains controversial. In this paper, we report the detection of variable broad emission bumps reminiscent of a supernova (SN) II-Plateau spectra taken a few days after the shock breakout in a second galaxy with variable superstrong coronal lines, SDSS J074820.67+471214.3. The coronal line spectrum shows unprecedentedly high ionization with superstrong [Fe X]?6376, [Fe XI]?7894, [Fe XIV]?5304, [S XII]?7612, and [Ar XIV]?4414, but without detectable optical [Fe VII] line emission. The coronal line luminosities are similar to those observed in bright Seyfert galaxies and 20 times more luminous than those reported in the hottest Type IIn SN 2005ip inferred from its strong coronal lines. The coronal lines (? ~ 120-240 km s-1) are much broader than the narrow emission lines (? ~ 40 km s-1) from the star-forming regions in the galaxy, but are nearly at the same systematic redshift. We also detected a variable non-stellar continuum emission from its Sloan Digital Sky Survey spectroscopy and Galaxy Evolution Explorer photometry. In the follow-up spectra taken 4-5 years later, the coronal lines, SN-like feature, and non-stellar continuum disappeared, while the [O III]?5007 intensity increased by a factor of about 10. Our analysis suggests that the coronal line region should be at least 10 light days in size and should be powered either by a steady ionizing source with a soft X-ray luminosity of at least a few 1042 erg s-1 or by a very luminous soft X-ray outburst. These findings can be more naturally explained by a star tidally disrupted by the central black hole than by an SN explosion. The similarity of the coronal line variability trend observed in the two galaxies suggests that the two transient events have the same origin, with SDSS J074820.67+471214.3 being caught at an earlier stage by the spectroscopic observation.

Wang, Ting-Gui; Zhou, Hong-Yan; Wang, Li-Fan; Lu, Hong-Lin; Xu, Dawei

2011-10-01

183

Heat shock protein 90 maintains the stability and function of transcription factor Broad Z7 by interacting with its Broad-Complex-Tramtrack-Bric-a-brac domain.  

PubMed

Heat shock protein 90 (Hsp90) is a highly conserved chaperone protein that interacts with various client proteins to mediate their folding and stability. The Broad-Complex-Tramtrack-Bric-a-brac (BTB) domain, also known as poxvirus and zinc finger (POZ) domain, exists widely in different proteins and is highly conserved. However, the stability mechanism of BTB domain-containing proteins has not been fully understood. Co-immunoprecipitation and a protein pull-down assay were performed to investigate the interaction between Hsp90 and the transcription factor Broad isoform Z7 (BrZ7) in vivo and in vitro. The middle domain of Hsp90 directly associated with the BTB domain of BrZ7. The Hsp90 inhibitor 17-(Allylamino)-17-demethoxygeldanamycin (17-AAG) interrupted the interaction between Hsp90 and BrZ7 and decreased the protein level of BrZ7 but did not affect the mRNA level of BrZ7. The addition of the proteasome inhibitor peptide aldehyde Cbz-leu-leu leucinal suppressed the 17-AAG-induced degradation of BrZ7. BTB domain deletion and 17-AAG treatment resulted in inhibition of BrZ7 function in gene expression in the 20-hydroxyecdysone and juvenile hormone pathways. These results reveal that the middle domain of Hsp90 associates with the BTB domain of BrZ7 to prevent BrZ7 degradation and maintain BrZ7 function in gene expression in the lepidopteran insect Helicoverpa armigera. PMID:25060629

Cai, M-J; Li, X-R; Pei, X-Y; Liu, W; Wang, J-X; Zhao, X-F

2014-12-01

184

STRUCTURE OF THE ACCRETION FLOW IN BROAD-LINE RADIO GALAXIES: THE CASE OF 3C 390.3  

SciTech Connect

We present XMM-Newton and Suzaku observations of the broad-line radio galaxy 3C 390.3 acquired in 2004 October and 2006 December, respectively. An archival Swift BAT spectrum from the 9 month survey is also analyzed, as well as an optical spectrum simultaneous to XMM-Newton. At soft X-rays, no absorption features are detected in the Reflection Grating Spectrometer spectrum of 3C 390.3; a narrow emission line is found at 0.564 keV, most likely originating in the narrow-line region. Both the EPIC and XIS data sets confirm the presence of an Fe K{alpha} emission line at 6.4 keV with equivalent width (EW) = 40 eV. The Fe K{alpha} line has a width FWHM {approx} 8800 km s{sup -1}, consistent within a factor of 2 with the width of the double-peaked H{alpha} line, suggesting an origin from the broad-line region. The data show for the first time a weak, broad bump extending from 5 to 7 keV. When fitted with a Gaussian, its centroid energy is 6.6 keV in the source's rest frame with FWHM of 43,000 km s{sup -1} and EW of 50 eV; its most likely interpretation is emission from He-like Fe (Fe XXV), suggesting the presence of an ionized medium in the inner regions of 3C 390.3. The broadband 0.5-100 keV continuum is well described by a single power law with photon index {gamma} = 1.6 and cutoff energy 157 keV, plus cold reflection with strength R = 0.5. In addition, ionized reflection is required to account for the 6.6 keV bump in the broadband continuum, yielding an ionization parameter {xi} {approx} 2700 erg cm s{sup -1}; the inner radius of the ionized reflector is constrained to be larger than 20r{sub G} , although this result depends on the assumed emissivity profile of the disk. If true, we argue that the lack of broad Fe K emission from within 20r{sub G} indicates that the innermost regions of the disk in 3C 390.3 are obscured and/or poorly illuminated. While the spectral energy distribution (SED) of 3C 390.3 is generally dominated by accretion-related continuum, during accretion low states the jet can significantly contribute in the optical to X-ray bands via synchrotron self-Compton emission. The Compton component is expected to extend to and peak at GeV gamma rays where it will be detected with the Fermi Gamma-Ray Space Telescope during its first few years of operation.

Sambruna, R. M.; Tueller, J. [NASA/GSFC, Code 661, Greenbelt, MD 20771 (United States); Reeves, J. N.; Lewis, K. T. [NASA/GSFC, Code 662, Greenbelt, MD 20771 (United States); Braito, V. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Eracleous, M. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Gliozzi, M. [George Mason University, Department of Physics and Astronomy, 4400 University Dr., Fairfax, VA 22030 (United States); Tavecchio, F. [INAF, Osserv. Astron. di Brera, via Bianchi 46, I-23807 Merate (Italy); Ballantyne, D. R. [Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, GA 30332 (United States); Ogle, P. M. [Spitzer Science Center, California Institute of Technology, Mail Code 220-6, Pasadena, CA 91125 (United States); Barth, A. J. [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697-4575 (United States)

2009-08-01

185

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

186

The origin of the strong soft excess and puzzling iron line complex in Mkn 841  

NASA Astrophysics Data System (ADS)

Mkn 841 has been observed during 3 different periods (January 2001, January 2005 and July 2005) by XMM-Newton for a total cumulated exposure time of ˜108 ks. We present in this paper a broad band spectral analysis of the complete EPIC-pn data sets. These observations confirm the presence of the strong soft excess and complex iron line profile known to be present in this source since a long time. They also reveal their extreme and puzzling spectral and temporal behaviors. Indeed, the 0.5-2 keV soft X-ray flux decreases by a factor 3 between 2001 and 2005 and the line shape appears to be a mixed of broad and narrow components, both variable but on different timescales. The broad-band 0.5-10 keV spectra are well described by a model including a primary power law continuum, a blurred photoionized reflection and a narrow iron line, the blurred reflection fitting self-consistently the soft excess and the broad line component. The origin and nature of the narrow component is unclear.

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

2006-12-01

187

The origin of the strong soft excess and puzzling iron line complex in Mkn 841  

NASA Astrophysics Data System (ADS)

Mkn 841 has been observed during 3 different periods (January 2001, January 2005 and July 2005) by XMM-Newton for a total cumulated exposure time of 108 ks. We present in this paper a broad band spectral analysis of the complete EPIC-pn data sets. These observations confirm the presence of the strong soft excess and complex iron line profile known to be present in this source since a long time. They also reveal their extreme and puzzling spectral and temporal behaviors. Indeed, the 0.5-2 keV soft X-ray flux decreases by a factor 3 between 2001 and 2005 and the line shape appears to be a mixed of broad and narrow components, both variable but on different timescales. The broad-band 0.5-10 keV spectra are well described by a model including a primary power law continuum, a blurred photoionized reflection and a narrow iron line, the blurred reflection fitting self-consistently the soft excess and the broad line component. The origin and nature of the narrow component is unclear.

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

2007-08-01

188

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

189

Reprocessing and variable cold absorption in the broad-line radio galaxy 3C 390.3  

NASA Astrophysics Data System (ADS)

A BeppoSAX observation of the Broad Line Radio-Galaxy 3C 390.3 is reported. For the first time, both the K_? iron line and a strong reflection hump, produced by the illumination of the primary X-ray emission on cold matter, are detected in this source. The 0.1-100 keV continuum is modeled by an absorbed hard power law (Gamma ~ 1.8) reflected at high energies by material with a fairly large covering factor (Omega /2pi =~ 1). The iron line is centered at =~ 6.4 keV (rest frame), is intrinsically narrow (sigma =73(+207}_{-73) eV), and has an equivalent width of =~ 140 eV. We discuss the results in the context of current models for AGNs and suggest that the primary X-ray power law continuum is probably produced by a hot inner flow, while the reprocessed radiation comes from an outer cold thin disk, and/or from a thick torus at even larger radii. Further observations with BeppoSAX could distinguish between the latter two cases. Beamed radiation associated to the radio jet is unlikely to contribute significantly to the X-ray emission. Finally, an historical study of the column density \

Grandi, P.; Guainazzi, M.; Haardt, F.; Maraschi, L.; Massaro, E.; Matt, G.; Piro, L.; Urry, C. M.

1999-03-01

190

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

191

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 at redshift z=1.6 - 1.8 in the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) imaging from Hubble Space Telescope/Wide Field Camera 3 (HST/WFC3). 69 candidates are selected by the large contribution of exceptionally bright emission lines to their near-infrared, broad-band fluxes. Supported by spectroscopic confirmation of strong [OIII] emission lines - with equivalent widths approximately 1000A - in the four candidates that have HST/WFC3 grism observations, we conclude that these objects are dwarf galaxies with approximately 10(exp 8) solar mass in stellar mass, undergoing an enormous star-burst phase with M*/M* of only approximately 10 Myr. The star formation activity and the co-moving number density (3.7 x 10(exp -4) Mpc(exp -3)) imply that strong, short-lived bursts play a significant, perhaps even dominant role in the formation and evolution of dwarf galaxies at z greater than 1. The observed star formation activity can produce in less than 5 Gyr the same amount of stellar mass density as is presently contained in dwarf galaxies. Therefore, our observations provide a strong indication that the stellar populations of present-day dwarf galaxies formed mainly in strong, short-lived bursts, mostly at z greater than 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.; Ferguson, H. C.; Scarlata, C.; Hathi, N. P.; Dunlop, J. S.; Newman, J. A.; Kocevski, D. D.; Lai, K.; Grogin, N. A.; Rodney, S. A.; Lee, K.-S.; Guo, Y.

2011-01-01

192

THE BROAD LINE REGION IN NGC 4051: AN INFLOW ILLUMINATED BY A 10{sup 5} K ACCRETION DISK  

SciTech Connect

Adopting a spherically symmetric steady-state ballistic inflow as the kinematic model for the gas distribution responsible for producing the H{alpha} emission line, and a central black hole (BH) mass of 1.7 Multiplication-Sign 10{sup 6} M{sub Sun} determined from prior reverberation mapping, leads to the following dimensions for the size of the broad line region (BLR) in NGC 4051; an inner radius {approx}3 lt-day and a lower limit to the outer radius {approx}475 lt-day. Thus, the previously determined reverberation size for the BLR marks just the inner radius of a much larger volume of ionized gas. The number of ionizing photons required to sustain the H{alpha} emission line luminosity exceeds the number observed to be available from the central active galactic nucleus (AGN) by a factor of 3-4. Such a large ionizing deficit can be reconciled if the BLR is ionized by a 10{sup 5} K accretion disk that is hidden from direct view by the high opacity of intervening H gas. A new definition is introduced for the ionization parameter that acknowledges the fact that H opacity significantly attenuates the flux of ionizing photons in the large, partially ionized nebula surrounding the AGN. Collectively, the results have important implications for BH masses estimated using reverberation radii and the structure of the BLR inferred from velocity-delay maps.

Devereux, Nick; Heaton, Emily, E-mail: devereux@erau.edu, E-mail: heatone@erau.edu [Department of Physics, Embry-Riddle Aeronautical University, Prescott, AZ 86301 (United States)

2013-08-20

193

Self-shadowing Effects of Slim Accretion Disks in Active Galactic Nuclei: Diverse Appearance of the Broad-line Region  

E-print Network

Supermassive black holes in active galactic nuclei (AGNs) undergo a wide range of accretion rates, which lead to diversity of appearance. We consider the effects of anisotropic radiation from accretion disks on the broad-line region (BLR), from the Shakura-Sunyaev regime to slim disks with super-Eddington accretion rates. The geometrically thick funnel of the inner region of slim disks produces strong self-shadowing effects that lead to very strong anisotropy of the radiation field. We demonstrate that the degree of anisotropy of the radiation fields grows with increasing accretion rate. As a result of this anisotropy, BLR clouds receive different spectral energy distributions depending on their location relative to the disk, resulting in diverse observational appearance of the BLR. We show that the self-shadowing of the inner parts of the disk naturally produces two dynamically distinct regions of the BLR, depending on accretion rate. These two regions manifest themselves as kinematically distinct components...

Wang, J -M; Du, P; Ho, L C

2014-01-01

194

VERY LONG BASELINE ARRAY MULTI-FREQUENCY POLARIMETRIC IMAGING OF RADIO-LOUD BROAD ABSORPTION LINE QUASARS  

SciTech Connect

We conducted the first multi-frequency polarimetric imaging of four broad absorption line (BAL) quasars using the Very Long Baseline Array at milliarcsecond resolutions to investigate the inclination of the nonthermal jet and test the hypothesis that radio sources in BAL quasars are still young. Among these four sources, J0928+446, J1018+0530, and J1405+4056 show one-sided structures in parsec scales and polarized emission detected in the core. These characteristics are consistent with those of blazars. We set constraints on viewing angles to <66 Degree-Sign for these jets in the framework of a Doppler beaming effect. J1159+0112 exhibits an unpolarized gigahertz-peaked spectrum component and several discrete blobs with steep spectra on both sides of the central component across {approx}1 kpc. These properties are consistent with those of young radio sources. We discuss the structures of jets and active galactic nucleus wind.

Hayashi, Takayuki J.; Nagai, Hiroshi [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588 (Japan); Doi, Akihiro, E-mail: t.hayashi@nao.ac.jp [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa, 252-5210 (Japan)

2013-07-20

195

VLTI/AMBER differential interferometry of the broad-line region of the quasar 3C273  

E-print Network

Unveiling the structure of the Broad Line Region (BLR) of AGNs is critical to understand the quasar phenomenon. Resolving a few BLRs by optical interferometry will bring decisive information to confront, complement and calibrate the reverberation mapping technique, basis of the mass-luminosity relation in quasars. BLRs are much smaller than the angular resolution of the VLT and Keck interferometers and they can be resolved only by differential interferometry very accurate measurements of differential visibility and phase as a function of wavelength. The latter yields the photocenter variation with wavelength, and constrains the size, position and velocity law of various regions of the BLR. AGNs are below the magnitude limit for spectrally resolved interferometry set by currently available fringe trackers. A new "blind" observation method and a data processing based on the accumulation of 2D Fourier power and cross spectra permitted us to obtain the first spectrally resolved interferometric observation of a BL...

Petrov, Romain G; Lagarde, Stéphane; Vannier, Martin; Rakshit, Suvendu; Marconi, Alessandro; Weigelt, Gerd

2014-01-01

196

PTF 10bzf (SN 2010ah): A BROAD-LINE Ic SUPERNOVA DISCOVERED BY THE PALOMAR TRANSIENT FACTORY  

SciTech Connect

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 {approx_equal}218 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 {sup 56}Ni, 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. [LIGO Laboratory, California Institute of Technology, MS 100-36, Pasadena, CA 91125 (United States); Ofek, E. O.; Kulkarni, S. R.; Kasliwal, M. M. [Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Frail, D. A. [National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM 87801 (United States); Poznanski, D.; Nugent, P. [Computational Cosmology Center, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Arcavi, I.; Gal-Yam, A.; Green, Y.; Xu, D.; Ben-ami, S. [Department of Particle Physics and Astrophysics, The Weizmann Institute of Science, Rehovot 76100 (Israel); Hurley, K. [Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Mazzali, P. A. [INAF-Osservatorio Astronomico, vicolo dell'Osservatorio 5, I-35122 Padova (Italy); Howell, D. A.; Murray, D. [Las Cumbres Observatory Global Telescope Network, Inc., Santa Barbara, CA 93117 (United States); Sullivan, M. [Department of Physics (Astrophysics), University of Oxford, DWB, Keble Road, Oxford OX1 3RH (United Kingdom); Bloom, J. S.; Cenko, S. B. [Department of Astronomy, 601 Campbell Hall, University of California, Berkeley, CA 94720-3411 (United States); Law, N. M., E-mail: corsi@caltech.edu [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto M5S 3H4, Ontario (Canada)

2011-11-10

197

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

198

THE LICK AGN MONITORING PROJECT: BROAD-LINE REGION RADII AND BLACK HOLE MASSES FROM REVERBERATION MAPPING OF Hbeta  

SciTech Connect

We have recently completed a 64-night spectroscopic monitoring campaign at the Lick Observatory 3-m Shane telescope with the aim of measuring the masses of the black holes in 12 nearby (z < 0.05) Seyfert 1 galaxies with expected masses in the range approx10{sup 6}-10{sup 7} M {sub sun} and also the well-studied nearby active galactic nucleus (AGN) NGC 5548. Nine of the objects in the sample (including NGC 5548) showed optical variability of sufficient strength during the monitoring campaign to allow for a time lag to be measured between the continuum fluctuations and the response to these fluctuations in the broad Hbeta emission. We present here the light curves for all the objects in this sample and the subsequent Hbeta time lags for the nine objects where these measurements were possible. The Hbeta lag time is directly related to the size of the broad-line region (BLR) in AGNs, and by combining the Hbeta lag time with the measured width of the Hbeta emission line in the variable part of the spectrum, we determine the virial mass of the central supermassive black hole in these nine AGNs. The absolute calibration of the black hole masses is based on the normalization derived by Onken et al., which brings the masses determined by reverberation mapping into agreement with the local M {sub BH}-sigma{sub *}relationship for quiescent galaxies. We also examine the time lag response as a function of velocity across the Hbeta line profile for six of the AGNs. The analysis of four leads to rather ambiguous results with relatively flat time lags as a function of velocity. However, SBS 1116+583A exhibits a symmetric time lag response around the line center reminiscent of simple models for circularly orbiting BLR clouds, and Arp 151 shows an asymmetric profile that is most easily explained by a simple gravitational infall model. Further investigation will be necessary to fully understand the constraints placed on the physical models of the BLR by the velocity-resolved response in these objects.

Bentz, Misty C.; Walsh, Jonelle L.; Barth, Aaron J. [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697 (United States); Baliber, Nairn; Bennert, Vardha Nicola; Greene, Jenny E.; Hidas, Marton G. [Physics Department, University of California, Santa Barbara, CA 93106 (United States); Canalizo, Gabriela; Hiner, Kyle D. [Institute of Geophysics and Planetary Physics, University of California, Riverside, CA 92521 (United States); Filippenko, Alexei V.; Ganeshalingam, Mohan; Lee, Nicholas; Li, Weidong; Serduke, Frank J. D.; Silverman, Jeffrey M.; Steele, Thea N. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Gates, Elinor L. [Lick Observatory, P.O. Box 85, Mount Hamilton, CA 95140 (United States); Malkan, Matthew A. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90024 (United States); Minezaki, Takeo; Sakata, Yu, E-mail: mbentz@uci.ed [Institute of Astronomy, School of Science, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan)

2009-11-01

199

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

NASA Astrophysics Data System (ADS)

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, and the Gross National Product (GNP) of an economy); and (3) creating a theoretical framework to enable predictions about the likely behavior of such systems in various conditions.

200

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

201

New Results from a Near-Infrared Search for Hidden Broad-Line Regions in Ultraluminous Infrared Galaxies  

E-print Network

This paper reports the latest results from a near-infrared search for hidden broad-line regions (BLRs: FWHM >~ 2,000 km/s) in ultraluminous infrared galaxies (ULIGs). The new sample contains thirty-nine ULIGs from the 1-Jy sample selected for their lack of BLRs at optical wavelengths. The results from this new study are combined with those from our previous optical and near-infrared surveys to derive the fraction of all ULIGs with optical or near-infrared signs of genuine AGN activity (either a BLR or [Si VI] emission). Comparisons of the dereddened emission-line luminosities of the optical or obscured BLRs detected in the ULIGs of the 1-Jy sample with those of optical quasars indicate that the obscured AGN/quasar in ULIGs is the main source of energy in at least 15 -- 25% of all ULIGs in the 1-Jy sample. This fraction is 30 -- 50% among ULIGs with L_ir > 10^{12.3} L_sun. These results are compatible with those from recent mid-infrared spectroscopic surveys carried out with ISO. (abridged)

S. Veilleux; D. B. Sanders; D. -C. Kim

1999-04-12

202

Are AGN Broad Emission Lines Formed by Discrete Clouds? --- Analysis of Keck High Resolution Spectroscopy of NGC 4151  

E-print Network

We search for a direct signature of discrete ''clouds'' in the broad line region (BLR) of the Seyfert galaxy NGC 4151. For this purpose we apply cross correlation (CC) analysis to a high resolution KECK spectrum of the galaxy. No such signature is found in the data. In order for cloud models to be compatible with this result, there must be at least $\\sim3\\times10^7$ emitting clouds in the BLR, where the limit is based on simulation of a homogeneous cloud population. More realistic distributions increase the lower limit to above $10^8$. These numbers are an order of magnitude improvement on our previous limit from Mrk 335, where the improvement comes from higher S/N, broader lines, and refined simulations. Combined with the predicted upper limit for the number of emitting clouds in NGC 4151 ($10^6-10^7$), the derived lower limit puts a strong constraint on the cloud scenario in the BLR of this object. Similar constraints can be paled on models where the emission originates in streams and sheets. Thus, this investigation suggests that the BELs in NGC 4151, and by extension in all AGNs, are not made of an ensemble of discrete independent emitters.

Nahum Arav; Thomas A. Barlow; Ari Laor; Wallace L. W. Sargent; Roger D. Blandford

1998-01-04

203

The Optical/NearIR Colors of Broad Absorption Line Quasars, Including the Candidate RadioLoud BAL Quasar 1556+3517  

E-print Network

The Optical/Near­IR Colors of Broad Absorption Line Quasars, Including the Candidate Radio­Loud BAL Quasar 1556+3517 Patrick B. Hall Steward Observatory, The University of Arizona, 933 N. Cherry Ave line quasar (RLBAL) has been reported by Becker et al. (1997). We present JHK observations

Martini, Paul

204

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

205

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

206

The fraction and mid-infrared properties of broad absorption line quasars from the Sloan Digital Sky Survey  

NASA Astrophysics Data System (ADS)

We present the results of a study which uses a sample of 1822 Sloan Digital Sky Survey (SDSS) quasars with reliable Wide-field Infrared Survey Explorer (WISE) detections in the redshift range 1.7? z?4.38 to investigate the mid-infrared fraction of broad absorption line (BAL) quasars. The BAL quasars in the sample include both high-ionization BAL (HiBAL) quasars that show broad absorption from C iv and low-ionization BAL (LoBAL) quasars that show additional broad absorption from Mg ii. The fraction of C iv BAL quasars with nonzero absorption index (AI) is found to be 38.7±1.2 %, in good agreement with that derived for the Two Micron All Sky Survey (2MASS) sample. The C iv BAL quasar fractions remain constant with magnitude in the WISE 3.4 ?m (W1) and 4.6 ?m (W2) bands, and increase rapidly with decreasing magnitude in the WISE 12 ?m (W3) and 22 ?m (W4) bands. The nonzero AI fraction of 44.5±2.1 % determined in the WISE W4 band is more likely to represent the intrinsic BAL quasar fraction. No evidence that the fraction is a strong function of redshift is found. At 1.7? z?2.15, the overall mid-infrared LoBAL fraction is and the fractions increase significantly with decreasing magnitude in all four of WISE bands. Moreover, it is found that the mean optical-to-WISE colors of BAL quasars are ?0.2 mag redder than that of non-BAL quasars, while the traditional (nonzero balnicity) BAL quasars are redder than the nontraditional BAL quasars by ?0.15 mag, which suggest a continuum of more reddening from non-BAL to nontraditional BAL to traditional BAL. No evidence that nontraditional BALs are a distinct class from traditional BALs is found. Finally, it is shown that the mean optical-to-WISE colors of LoBALs are ?0.4 mag redder than that of HiBALs at 1.7? z?2.15.

Pu, Xingting

2014-02-01

207

Constraining UV Continuum Slopes of Active Galactic Nuclei with CLOUDY Models of Broad-line Region Extreme-ultraviolet Emission Lines  

NASA Astrophysics Data System (ADS)

Understanding the composition and structure of the broad-line region (BLR) of active galactic nuclei (AGNs) is important for answering many outstanding questions in supermassive black hole evolution, galaxy evolution, and ionization of the intergalactic medium. We used single-epoch UV spectra from the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope to measure EUV emission-line fluxes from four individual AGNs with 0.49 <= z <= 0.64, two AGNs with 0.32 <= z <= 0.40, and a composite of 159 AGNs. With the CLOUDY photoionization code, we calculated emission-line fluxes from BLR clouds with a range of density, hydrogen ionizing flux, and incident continuum spectral indices. The photoionization grids were fit to the observations using single-component and locally optimally emitting cloud (LOC) models. The LOC models provide good fits to the measured fluxes, while the single-component models do not. The UV spectral indices preferred by our LOC models are consistent with those measured from COS spectra. EUV emission lines such as N IV ?765, O II ?833, and O III ?834 originate primarily from gas with electron temperatures between 37,000 K and 55,000 K. This gas is found in BLR clouds with high hydrogen densities (n H >= 1012 cm–3) and hydrogen ionizing photon fluxes (?H >= 1022 cm–2 s–1). 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.

Moloney, Joshua; Shull, J. Michael

2014-10-01

208

Partial coverage of the broad-line region of Q1232+082 by an intervening H2-bearing cloud  

NASA Astrophysics Data System (ADS)

We present a detailed analysis of the partial coverage of the Q1232+082 (zem= 2.57) broad-line region (BLR) by an intervening H2-bearing cloud at zabs= 2.3377. Using curve of growth analysis and line profile fitting, we demonstrate that the H2-bearing component of the cloud covers the quasi-stellar object (QSO) intrinsic continuum source completely but only part of the BLR. We find that only 48 ± 6 per cent of the C IV BLR emission is covered by the C I absorbing gas. We observe residual light (˜6 per cent) as well in the bottom of the O I ?1302 absorption from the cloud, redshifted on top of the QSO Lyman ? emission line. Therefore, the extent of the neutral phase of the absorbing cloud is not large enough to cover all of the background source. The most likely explanation for this partial coverage is the small size of the intervening cloud, which is comparable to the BLR size. We estimate the number densities in the cloud: ?˜ 110 cm-3 for the H2-bearing core and nH˜ 30 cm-3 for the neutral envelope. Given the column densities, N(H2) = 3.71 ± 0.97 × 1019 cm-2 and N(H I) = 7.94 ± 1.6 × 1020 cm-2, we derive the linear size of the H2-bearing core and the neutral envelope along the line of sight to be ?˜ 0.15+0.05-0.05 pc and ?˜ 8.2+6.5-4.1 pc, respectively. We estimate the size of the C IV BLR by two ways: (i) extrapolating size-luminosity relations derived from reverberation observations and (ii) assuming that the H2-bearing core and the BLR are spherical in shape and the results are ˜0.26 and ˜0.18 pc, respectively. The large size we derive for the extent of the neutral phase of the absorbing cloud together with a covering factor of ˜0.94 of the Lyman ? emission means that the Lyman ? BLR is probably fully covered but that the Lyman ? emission extends well beyond the limits of the BLR. Based on observations carried out at European Southern Observatory with the Ultraviolet and Visual Echelle Spectrograph (UVES) mounted on the Very Large Telescope (VLT), unit Kueyen, on Cerro Paranal in Chile, under programmes ID 65.P-0038 (P.I. Srianand), 68.A-0106, 69.A-0061, 70.A-0017 (P.I. Petitjean) and 71.B-0136 (P.I. Srianand).

Balashev, S. A.; Petitjean, P.; Ivanchik, A. V.; Ledoux, C.; Srianand, R.; Noterdaeme, P.; Varshalovich, D. A.

2011-11-01

209

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

210

NuSTAR Reveals the Comptonizing Corona of the Broad-line Radio Galaxy 3C 382  

NASA Astrophysics Data System (ADS)

Broad-line radio galaxies (BLRGs) are active galactic nuclei that produce powerful, large-scale radio jets, but appear as Seyfert 1 galaxies in their optical spectra. In the X-ray band, BLRGs also appear like Seyfert galaxies, but with flatter spectra and weaker reflection features. One explanation for these properties is that the X-ray continuum is diluted by emission from the jet. Here, we present two NuSTAR observations of the BLRG 3C 382 that show clear evidence that the continuum of this source is dominated by thermal Comptonization, as in Seyfert 1 galaxies. The two observations were separated by over a year and found 3C 382 in different states separated by a factor of 1.7 in flux. The lower flux spectrum has a photon-index of \\Gamma =1.68^{+0.03}_{-0.02}, while the photon-index of the higher flux spectrum is \\Gamma =1.78^{+0.02}_{-0.03}. Thermal and anisotropic Comptonization models provide an excellent fit to both spectra and show that the coronal plasma cooled from kTe = 330 ± 30 keV in the low flux data to 231^{+50}_{-88} keV in the high flux observation. This cooling behavior is typical of Comptonizing corona in Seyfert galaxies and is distinct from the variations observed in jet-dominated sources. In the high flux observation, simultaneous Swift data are leveraged to obtain a broadband spectral energy distribution and indicates that the corona intercepts ~10% of the optical and ultraviolet emitting accretion disk. 3C 382 exhibits very weak reflection features, with no detectable relativistic Fe K? line, that may be best explained by an outflowing corona combined with an ionized inner accretion disk.

Ballantyne, D. R.; Bollenbacher, J. M.; Brenneman, L. W.; Madsen, K. K.; Balokovi?, M.; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Gandhi, P.; Hailey, C. J.; Harrison, F. A.; Lohfink, A. M.; Marinucci, A.; Markwardt, C. B.; Stern, D.; Walton, D. J.; Zhang, W. W.

2014-10-01

211

Variability of Soft X-ray Spectral Shape: Narrow-Line Seyfert 1 Galaxies versus Broad-Line Seyfert 1 Galaxies  

E-print Network

In order to understand how the soft X-ray spectra vary we present the Hardness Ratio 1 versus Count Rates (HR1-CTs) correlation of 8 Narrow-line Seyfert 1 Galaxies (NLS1s) and 14 Broad-line Seyfert1 Galaxies (BLS1s) obtained during the ROSAT PSPC pointing observations. According to our criteria, six of the NLS1s show a positive HR1-CTs correlation, and seven of the BLS1s display an anti-correlation of HR1 versus CTs. The other 2 NLS1s and 7 BLS1s do not show a clear HR1-CTs correlation. From these we can see that the NLS1s statistically show a different spectral shape variability with flux change from the BLS1s: the spectra of NLS1s become harder as total flux increases while those of BLS1s soften. We attribute the different spectral variations to a strong stable 'soft excess' in NLS1s, while it is weak in BLS1s. For two types of objects, the power law component similarly becomes softer with increasing intensity. These imply that the soft excess originates from the Big Blue Bump and power law emission is from Compton upscattering of UV or Soft X-ray photons. Our results are consistent with what is widely accepted that NLS1s have smaller black hole masses and higher accretion rates than BLS1s.

Linpeng Cheng; Jianyan Wei; Yongheng Zhao

2001-10-26

212

XMM-NEWTON OBSERVATIONS OF THE RADIO-LOUD BROAD ABSORPTION LINE QUASAR FBQS J131213.5+231958  

SciTech Connect

We present XMM-Newton observations of the broad absorption line (BAL) quasar FBQS J131213.5+231958. The X-ray spectrum of the source can be well described by an absorbed power-law model in which the absorber is either ionized or only partially covers the continuum source. This can explain the apparent lack of absorption observed in the Chandra spectrum with low signal-to-noise ratio. While the power-law slope of the spectrum is similar to that of non-BAL radio-loud quasars, the Eddington luminosity ratio is likely to be significantly higher than the mean. This shows that in high-mass black holes (BHs), high Eddington accretion may not result in as steep of a spectrum as in lower-mass BHs. This provides important constraints for accretion disk models. It also provides support to the idea that BAL quasars, at least their radio-loud subclass, represent an early evolutionary stage of quasars.

Mathur, Smita [Astronomy Department, Ohio State University, Enarson Hall, 140 W. 18th Avenue, Columbus, OH 43210 (United States); Dai Xinyu, E-mail: smita@astronomy.ohio-state.ed, E-mail: dai@nhn.ou.ed [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks Street, Norman, OK 73019 (United States)

2010-12-15

213

Modeling the spectral energy distribution of 3C 454.3 in a "flat" broad-line region scenario  

NASA Astrophysics Data System (ADS)

The broad-line region (BLR) of flat-spectrum radio quasars (FSRQs) could have a "flat" geometrical structure to allow GeV gamma-ray photons to escape, to produce the observed gamma-ray flares with short timescales. In this paper, we collect the quasi-simultaneous spectral energy distributions (SEDs) of the FSRQ 3C 454.3 obtained by the multi-wavelength campaigns spanning from 2007 July to 2011 January, and use a model with a "flat" structure BLR, an accretion disc and a dust torus to explain the SEDs of gamma-ray outbursts. We obtain the following results: (i) the jet is almost in equipartition between magnetic and particle energy densities during the outbursts; (ii) when the emitting region is located inside the cavity of the BLR, the covering factor fBLR of the BLR is very small-as the emitting region goes into the BLR structure, fBLR increases; (iii) the aperture angle ? describing the BLR structure is about 45°; (iv) the central black hole mass is about 5 × 108 M? rather than 4.4 × 109 M?.

Lei, Maichang; Wang, Jiancheng

2014-10-01

214

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

215

NuSTAR Reveals the Comptonizing Corona of the Broad-Line Radio Galaxy 3C 382  

E-print Network

Broad-line radio galaxies (BLRGs) are active galactic nuclei that produce powerful, large-scale radio jets, but appear as Seyfert 1 galaxies in their optical spectra. In the X-ray band, BLRGs also appear like Seyfert galaxies, but with flatter spectra and weaker reflection features. One explanation for these properties is that the X-ray continuum is diluted by emission from the jet. Here, we present two NuSTAR observations of the BLRG 3C 382 that show clear evidence that the continuum of this source is dominated by thermal Comptonization, as in Seyfert 1 galaxies. The two observations were separated by over a year and found 3C 382 in different states separated by a factor of 1.7 in flux. The lower flux spectrum has a photon-index of $\\Gamma=1.68^{+0.03}_{-0.02}$, while the photon-index of the higher flux spectrum is $\\Gamma=1.78^{+0.02}_{-0.03}$. Thermal and anisotropic Comptonization models provide an excellent fit to both spectra and show that the coronal plasma cooled from $kT_e=330\\pm 30$ keV in the low f...

Ballantyne, D R; Brenneman, L W; Madsen, K K; Balokovic, M; Boggs, S E; Christensen, F E; Craig, W W; Gandhi, P; Hailey, C J; Harrison, F A; Lohfink, A M; Marinucci, A; Markwardt, C B; Stern, D; Walton, D J; Zhang, W W

2014-01-01

216

On the dynamics of clouds in the broad-line region of AGNs with an ADAF atmosphere  

E-print Network

We investigate orbital motion of spherical, pressure-confined clouds in the broad-line region (BLR) of active galactic nuclei (AGN). The combined influence of gravity of the central object and the non-isotropic radiation of the central source are taking into account. While most of the previous studies assume that the pressure of the intercloud gaseous component is proportional to a power-law function of the radial coordinate, we generalize it to a case where the external pressure depends on both the radial distance and the latitudinal angle. Our prescribed pressure profile determines the radius and the column density of BLR clouds as a function of their location. We also discuss about stability of the orbits and a condition for the existence of bound orbits is obtained. We found that BLR clouds tend to populate the equatorial regions more than other parts simply because of the stability considerations. Although this finding is obtained for a particular pressure profile, we think, this result is valid as long ...

Khajenabi, Fazeleh

2014-01-01

217

Weak Hard X-Ray Emission from Broad Absorption Line Quasars: 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 (?eff ? 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 (gsim 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, B.; Brandt, W. N.; Alexander, D. M.; Stern, D.; Teng, S. H.; Arévalo, P.; Bauer, F. E.; Boggs, S. E.; Christensen, F. E.; Comastri, A.; Craig, W. W.; Farrah, D.; Gandhi, P.; Hailey, C. J.; Harrison, F. A.; Koss, M.; Ogle, P.; Puccetti, S.; Saez, C.; Scott, A. E.; Walton, D. J.; Zhang, W. W.

2014-10-01

218

A Comparative Study of Optical/Ultraviolet Variability of Narrow-line Seyfert 1 and Broad-line Seyfert 1 Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

The ensemble optical/ultraviolet (UV) variability of narrow-line Seyfert 1 (NLS1)-type active galactic nuclei (AGNs) is investigated, based on a sample selected from the Sloan Digital Sky Survey (SDSS) Stripe 82 region with multi-epoch photometric scanning data. As a comparison, a control sample of broad-line Seyfert 1 (BLS1)-type AGNs is also incorporated. To quantify properly the intrinsic variation amplitudes and their uncertainties, a novel method of parametric maximum likelihood is introduced that has, as we argued, certain virtues over previously used methods. The majority of NLS1-type AGNs exhibit significant variability on timescales from about 10 days to a few years with, however, smaller amplitudes on average compared to BLS1-type AGNs. About 20 NLS1-type AGNs that show relatively large variations are presented and may deserve future monitoring observations, for instance, reverberation mapping. The averaged structure functions of variability, constructed using the same maximum likelihood method, show remarkable similarity in shape for the two types of AGNs on timescales longer than about 10 days, which can be approximated by a power law or an exponential function. This, along with other similar properties, such as the wavelength-dependent variability, is indicative of a common dominant mechanism responsible for the long-term optical/UV variability of both NLS1- and BLS1-type AGNs. Toward the short timescales, however, there is tentative evidence that the structure function of NLS1-type AGNs continues to decline, whereas that of BLS1-type AGNs flattens with some residual variability on timescales of days. If this can be confirmed, it may suggest that an alternative mechanism, such as X-ray reprocessing, starts to dominate in BLS1-type AGNs, but not in NLS1-type AGNs, on such timescales.

Ai, Y. L.; Yuan, W.; Zhou, H.; Wang, T. G.; Dong, X.-B.; Wang, J. G.; Lu, H. L.

2013-04-01

219

A COMPARATIVE STUDY OF OPTICAL/ULTRAVIOLET VARIABILITY OF NARROW-LINE SEYFERT 1 AND BROAD-LINE SEYFERT 1 ACTIVE GALACTIC NUCLEI  

SciTech Connect

The ensemble optical/ultraviolet (UV) variability of narrow-line Seyfert 1 (NLS1)-type active galactic nuclei (AGNs) is investigated, based on a sample selected from the Sloan Digital Sky Survey (SDSS) Stripe 82 region with multi-epoch photometric scanning data. As a comparison, a control sample of broad-line Seyfert 1 (BLS1)-type AGNs is also incorporated. To quantify properly the intrinsic variation amplitudes and their uncertainties, a novel method of parametric maximum likelihood is introduced that has, as we argued, certain virtues over previously used methods. The majority of NLS1-type AGNs exhibit significant variability on timescales from about 10 days to a few years with, however, smaller amplitudes on average compared to BLS1-type AGNs. About 20 NLS1-type AGNs that show relatively large variations are presented and may deserve future monitoring observations, for instance, reverberation mapping. The averaged structure functions of variability, constructed using the same maximum likelihood method, show remarkable similarity in shape for the two types of AGNs on timescales longer than about 10 days, which can be approximated by a power law or an exponential function. This, along with other similar properties, such as the wavelength-dependent variability, is indicative of a common dominant mechanism responsible for the long-term optical/UV variability of both NLS1- and BLS1-type AGNs. Toward the short timescales, however, there is tentative evidence that the structure function of NLS1-type AGNs continues to decline, whereas that of BLS1-type AGNs flattens with some residual variability on timescales of days. If this can be confirmed, it may suggest that an alternative mechanism, such as X-ray reprocessing, starts to dominate in BLS1-type AGNs, but not in NLS1-type AGNs, on such timescales.

Ai, Y. L. [Department of Astronomy, Peking University, Beijing 100871 (China); Yuan, W. [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Zhou, H.; Wang, T. G.; Dong, X.-B.; Lu, H. L. [Key Laboratory for Research in Galaxies and Cosmology, University of Science and Technology of China, Chinese Academy of Science, Hefei, Anhui 230026 (China); Wang, J. G., E-mail: aiyl@pku.edu.cn, E-mail: wmy@nao.cas.cn [National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, P.O. Box 110, Kunming, Yunnan (China)

2013-04-15

220

To be published in Astrophysical Journal Optical Monitoring of the Broad-Line Radio Galaxy 3C 390.3  

E-print Network

variations were measured for the hydrogen Balmer lines H, H, H, and for the helium line He ii4686, as well in the double peaked line profiles, as well as the blue and red outer profile wings, vary simultaneously within of the line emitting gas. Combining the time delay of the strong Balmer emission lines of H and H

Dietrich, Matthias

221

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

PubMed Central

NADH:ubiquinone reductase (EC 1.6.19.3), or complex I, was isolated from broad bean (Vicia faba L.) mitochondria. Osmotic shock and sequential treatment with 0.2% (v/v) Triton X-100 and 0.5% (w/v) [3-cholamidopropyl)dimethylammonio]-1-propanesulfate (CHAPS) removed all other NADH dehydrogenase activities. Complex I was solubilized in the presence of 4% Triton X-100 and then purified by sucrose-gradient centrifugation in the presence of the same detergent. The second purification step was hydroxylapatite chromatography. Substitution of CHAPS for Triton X-100 helped remove contaminants such as ATPase. The high molecular mass complex is composed of at least 26 subunits with molecular masses ranging from 6000 to 75,000 kD. The purified complex I reduced ferricyanide and ubiquinone analogs but not cytochrome c. NADPH could not substitute for NADH as an electron donor. The KM for NADH was 20 microM at the optimum pH of 8.0. The NH2-terminal sequence of several subunits was determined, revealing the ambiguous nature of the 42-kD subunit. PMID:8108509

Leterme, S; Boutry, M

1993-01-01

222

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

223

The Discovery of Broad P Cygni X-ray Lines from Circinus X-1 with the Chandra High Energy Transmission Grating Spectrometer  

E-print Network

We present the first grating-resolution X-ray spectra of the X-ray binary Cir X-1, obtained with the High Energy Transmission Grating Spectrometer on Chandra. These reveal a rich set of lines from H-like and/or He-like Ne, Mg, Si, S and Fe detected with a high signal-to-noise ratio. The lines are broad (+/- 2000 km/s) and show P Cygni profiles. The absorption components of the lines extend to low velocity, and they have about the same widths and strengths as the corresponding emission components. The widths of the X-ray P Cygni lines are comparable to that of the broad component of the strong, asymmetric H-alpha line from Cir X-1, suggesting that the two phenomena may be related. We discuss outflow models and propose that the P Cygni profiles may arise in the moderate temperature (5 x 10^6 K) region of the wind from an X-ray heated accretion disk. This basic picture strengthens the idea that the accretion disk in Cir X-1 is viewed in a relatively edge-on manner, and it suggests that Cir X-1 is the X-ray binary analog of a Broad Absorption Line quasar.

W. N. Brandt; N. S. Schulz

2000-07-26

224

STRONG RESPONSE OF THE VERY BROAD H{beta} EMISSION LINE IN THE LUMINOUS RADIO-QUIET QUASAR PG 1416-129  

SciTech Connect

We report new spectroscopic observations performed in 2010 and 2011 for the luminous radio-quiet quasar PG 1416-129. Our new spectra with high quality cover both H{beta} and H{alpha} regions, and show negligible line profile variation within a timescale of one year. The two spectra allow us to study the variability of the Balmer line profile by comparing the spectra with previous ones taken at 10 and 20 years ago. By decomposing the broad Balmer emission lines into two Gaussian profiles, our spectral analysis suggests a strong response to the continuum level for the very broad component, and significant variations in both bulk blueshift velocity/FWHM and flux for the broad component. The new observations additionally indicate flat Balmer decrements (i.e., too strong H{beta} emission) at the line wings, which is hard to reproduce using recent optically thin models. With these observations we argue that a separate inner optically thin emission-line region might not be necessary in the object to reproduce the observed line profiles.

Wang, J.; Li, Y., E-mail: wj@bao.ac.cn [National Astronomical Observatories, Chinese Academy of Science, Beijing (China)

2011-11-20

225

The ultraviolet spectrum of the gravitational lens candidate UM 425 = QSO 1120+019: Evidence for broad absorption line (BAL) structure  

NASA Technical Reports Server (NTRS)

The UV line profile structure of high-ionization resonance lines found with the International Ultraviolet Explorer (IUE) in the brightest of four multiply imaged sources (images-A) in the candidate gravitational lens UM 425 = QSO 1120+019 indicates broad absorption line (BAL) structure. The deep-broad trough associated with the O IV line extends to velocities approiximately -12,000 km/s, and contains disrete features that suggest multicomponent velocity structure. This structure may include contributions from C IV absorption from the early-type galaxy that is believed to lens UM 425. A strong absorption feature in the blue wing of the Lyman-alpha lambda 1216 emission line may be a Lyman alpha absorption system at a Z(sub Ly alpha) = 1.437 +/- 0.003, or it may be formed by the superposition of the broad N V lambda lambda 1238, 1242 absorption trough on the extended blue emission wing of the QSO Lyman-alpha line. We obtained a redshift of Z(sub QSO) = 1.471 +/- 0.003 from Lyman-alpha lambda 1215, consistent with the redshift found by Meylan and Djorgovski in the optical. The Lyman-alpha line appears unusally weak due to the presence of N V lambda 1240 BAL absorption. A Lyman-limit absorption system at lambda 912 was not observed in the QSO rest frame. The detection of BAL structure in the other weaker ground-state resonance lines of N II (l) and S IV (l) was not found, suggesting these lines are formed in a region that is distinct from the BAL component. Detection of BAL structure in the other fainter images in this system with Hubble Space Telescope (HST) instrumentation, similar to structure observed here in image A, could provide evidence that UM 425 is a gravitational lens.

Michelitsianos, A. G.; Oliversen, R. J.

1995-01-01

226

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

SciTech Connect

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

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

2007-07-09

227

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

NASA Astrophysics Data System (ADS)

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

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

2012-08-01

228

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

229

Self-shadowing Effects of Slim Accretion Disks in Active Galactic Nuclei: The Diverse Appearance of the Broad-line Region  

NASA Astrophysics Data System (ADS)

Supermassive black holes in active galactic nuclei (AGNs) undergo a wide range of accretion rates, which lead to diversity of appearance. We consider the effects of anisotropic radiation from accretion disks on the broad-line region (BLR) from the Shakura-Sunyaev regime to slim disks with super-Eddington accretion rates. The geometrically thick funnel of the inner region of slim disks produces strong self-shadowing effects that lead to very strong anisotropy of the radiation field. We demonstrate that the degree of anisotropy of the radiation fields grows with increasing accretion rate. As a result of this anisotropy, BLR clouds receive different spectral energy distributions depending on their location relative to the disk, resulting in the diverse observational appearance of the BLR. We show that the self-shadowing of the inner parts of the disk naturally produces two dynamically distinct regions of the BLR, depending on accretion rate. These two regions manifest themselves as kinematically distinct components of the broad H? line profile with different line widths and fluxes, which jointly account for the Lorentzian profile generally observed in narrow-line Seyfert 1 galaxies. In the time domain, these two components are expected to reverberate with different time lags with respect to the varying ionizing continuum, depending on the accretion rate and the viewing angle of the observer. The diverse appearance of the BLR due to the anisotropic ionizing energy source can be tested by reverberation mapping of H? and other broad emission lines (e.g., Fe II), providing a new tool to diagnose the structure and dynamics of the BLR. Other observational consequences of our model are also explored.

Wang, Jian-Min; Qiu, Jie; Du, Pu; Ho, Luis C.

2014-12-01

230

On the origin of the broad, relativistic iron line of MCG-6-30-15 observed by XMM-Newton  

NASA Astrophysics Data System (ADS)

The relativistic iron line profile recently observed by XMM-Newton in the spectrum of the Seyfert 1 galaxy MCG-6-30-15 (Wilms et al. \\cite{Wilms01}) is discussed in the framework of the lamp-post model. It is shown that the steep disc emissivity, the large line equivalent width and the amount of Compton reflection can be self-consistently reproduced in this scenario.

Martocchia, A.; Matt, G.; Karas, V.

2002-03-01

231

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

SciTech Connect

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

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

2012-12-01

232

The broad bacterial blight resistance of rice line CBB23 is triggered by a novel transcription activator-like (TAL) effector of Xanthomonas oryzae pv. oryzae.  

PubMed

Bacterial blight (BB), caused by Xanthomonas oryzae pv. oryzae (Xoo), is not only a disease devastating rice production worldwide, but also an ideal model system for the study of the interaction between plants and their bacterial pathogens. The rice near-isogenic line (NIL) CBB23, derived from a cross between a wild rice Oryza rufipogon accession (RBB16) and a susceptible indica rice variety (Jingang 30), is highly resistant to all field Xoo strains tested so far. Although the BB resistance of CBB23 has been widely used in rice breeding programmes, the mechanism of its extremely broad-spectrum resistance remains unknown. Here, we report the molecular cloning of an avirulence gene, designated as avrXa23, from Xoo strain PXO99(A) . We validate that AvrXa23, a novel transcription activator-like effector, specifically triggers the broad-spectrum BB resistance in CBB23. The prevalence of avrXa23 in all 38 Xoo strains surveyed may explain the broad-spectrum feature of BB resistance in CBB23. The results will significantly facilitate the molecular cloning of the corresponding resistance (R) gene in the host, and provide new insights into our understanding of the molecular mechanism for broad-spectrum disease resistance in plants. PMID:24286630

Wang, Chun-Lian; Qin, Teng-Fei; Yu, Hong-Man; Zhang, Xiao-Ping; Che, Jin-Ying; Gao, Ying; Zheng, Chong-Ke; Yang, Bing; Zhao, Kai-Jun

2014-05-01

233

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. PMID:24212576

2014-01-01

234

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

235

Misalignment of the Jet and the Normal to the Dusty Torus in the Broad Absorption Line QSO FIRST J155633.8+351758  

NASA Astrophysics Data System (ADS)

We performed Very Long Baseline Array observations of the broad absorption line quasar FIRST J155633.8+351758, "the first radio loud BALQSO." Our observations at 15.3 GHz partially resolved a secondary component at position angle (P.A.) ?35°. We combine this determination of the radio jet projection on the sky plane, with the constraint that the jet is viewed within 14.°3 of the line of sight (as implied by the high variability brightness temperature) and with the P.A. of the optical/UV continuum polarization in order to study the quasar geometry. Within the context of the standard model, the data indicates a "dusty torus" (scattering surface) with a symmetry axis tilted relative to the accretion disk normal and a polar broad absorption line outflow aligned with the accretion disk normal. We compare this geometry to that indicated by the higher resolution radio data, brightness temperature, and optical/UV continuum polarization P.A. of a similar high optical polarization BALQSO, Mrk 231. A qualitatively similar geometry is found in these two polar BALQSOs; the continuum polarization is determined primarily by the tilt of the dusty torus.

Reynolds, Cormac; Punsly, Brian; O'Dea, Christopher P.

2013-08-01

236

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

237

MISALIGNMENT OF THE JET AND THE NORMAL TO THE DUSTY TORUS IN THE BROAD ABSORPTION LINE QSO FIRST J155633.8+351758  

SciTech Connect

We performed Very Long Baseline Array observations of the broad absorption line quasar FIRST J155633.8+351758, ''the first radio loud BALQSO''. Our observations at 15.3 GHz partially resolved a secondary component at position angle (P.A.) Almost-Equal-To 35 Degree-Sign . We combine this determination of the radio jet projection on the sky plane, with the constraint that the jet is viewed within 14. Degree-Sign 3 of the line of sight (as implied by the high variability brightness temperature) and with the P.A. of the optical/UV continuum polarization in order to study the quasar geometry. Within the context of the standard model, the data indicates a ''dusty torus'' (scattering surface) with a symmetry axis tilted relative to the accretion disk normal and a polar broad absorption line outflow aligned with the accretion disk normal. We compare this geometry to that indicated by the higher resolution radio data, brightness temperature, and optical/UV continuum polarization P.A. of a similar high optical polarization BALQSO, Mrk 231. A qualitatively similar geometry is found in these two polar BALQSOs; the continuum polarization is determined primarily by the tilt of the dusty torus.

Reynolds, Cormac [ICRAR-Curtin University, GPO Box U1987, Perth, Western Australia 6102 (Australia); Punsly, Brian [1415 Granvia Altamira, Palos Verdes Estates, CA 90274 (United States); O'Dea, Christopher P., E-mail: brian.punsly1@verizon.net, E-mail: brian.punsly@comdev-usa.com [Laboratory for Multiwavelength Astrophysics, School of Physics and Astronomy, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States)

2013-08-10

238

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

NASA Astrophysics Data System (ADS)

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.

1995-04-01

239

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

Microsoft Academic Search

We report the first high-energy detection of PG 1700+518, a well-known low-ionization broad absorption line quasar (quasi-stellar object, QSO). Due to previous X-ray non-detection, it was classified as soft X-ray weak QSO. We observed PG 1700+518 with XMM-Newton for about 60 ks divided in three exposures. The spectrum below 2 keV is very steep, Gamma˜ 2.4-3.8, while at higher energies

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

2011-01-01

240

New Results from a Near-Infrared Search for Hidden Broad-Line Regions in Ultraluminous Infrared Galaxies  

Microsoft Academic Search

This paper reports the latest results from a near-infrared search for hidden\\u000abroad-line regions (BLRs: FWHM >~ 2,000 km\\/s) in ultraluminous infrared\\u000agalaxies (ULIGs). The new sample contains thirty-nine ULIGs from the 1-Jy\\u000asample selected for their lack of BLRs at optical wavelengths. The results from\\u000athis new study are combined with those from our previous optical and\\u000anear-infrared surveys

Sylvain Veilleux; D. B. Sanders

1999-01-01

241

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

E-print Network

We present a high resolution X-ray spectrum of the iron K bandpass in MCG-6-30-15 based on a 522 ksec observation with Chandra's High Energy Transmission Grating Spectrometer. The Chandra spectrum is consistent with the presence of a relativistically broadened, highly redshifted iron K alpha emission line with a similar profile to previous observations. A number of narrow features are detected above 2 keV, including a narrow Fe K alpha emission line and narrow absorption lines from H- and He-like Fe, H-like S and H-like Si. This absorption is well described by a photoionized plasma with a column density log N_H = 23.2 and an ionization parameter log xi = 3.6, assuming the iron abundance has the Solar value and a velocity dispersion parameter b = 100 km/s. Applying this absorption model to a high fidelity XMM-Newton EPIC-pn spectrum we find that a broad iron line is still required with emission extending to within 1.9 gravitational radii of the black hole. If the iron line comes from an accretion disk truncated at the innermost stable circular orbit, this indicates that the black hole must be spinning rapidly with a>0.95. Ionized absorption models attempting to explain the 3-6 keV spectral curvature without strong gravity predict absorption lines in the 6.4-6.6 keV range that are inconsistent with the Chandra spectrum. The H- and He-like iron absorption lines in the Chandra spectrum are blueshifted by 2.0 (+0.7/-0.9) x 10^3 km/s compared to the source frame, and may originate in a high velocity, high ionization component of the warm absorber outflow. This high ionization component may dominate the energy budget of the outflow, and account for a significant fraction of the outflowing mass. (Abstract truncated).

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

2005-06-03

242

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

SciTech Connect

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

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

2012-12-20

243

The Lack of Broad-Line Regions in Low Accretion Rate Active Galactic Nuclei as Evidence of Their Origin in the Accretion Disk  

NASA Astrophysics Data System (ADS)

In this Letter, we present evidence suggesting that the absence or presence of hidden broad-line regions (HBLRs) in Seyfert 2 galaxies is regulated by the rate at which matter accretes onto a central supermassive black hole, in units of the Eddington rate. Evidence is based on data from a subsample of type 2 active galactic nuclei extracted from the Tran spectropolarimetric sample and made up of all those sources that also have good-quality X-ray spectra available and for which a bulge luminosity can be estimated. We use the intrinsic (i.e., unabsorbed) X-ray luminosities of these sources and their black hole masses (estimated by using the well-known relationship between nuclear mass and bulge luminosity in galaxies) to derive the nuclear accretion rate in Eddington units. We find that virtually all HBLR sources have accretion rates larger than a threshold value of mthres~=10-3 (in Eddington units), while non-HBLR sources lie at m<~mthres. These data nicely fit predictions from a model proposed by Nicastro in which the broad-line regions (BLRs) are formed by accretion disk instabilities occurring in proximity of the critical radius at which the disk changes from gas pressure dominated to radiation pressure dominated. This radius diminishes with decreasing m for low enough accretion rates (and therefore luminosities), the critical radius becomes smaller than the innermost stable orbit and BLRs cannot form.

Nicastro, Fabrizio; Martocchia, Andrea; Matt, Giorgio

2003-05-01

244

An HST/COS Observation of Broad Ly$\\alpha$ Emission and Associated Absorption Lines of the BL Lacertae Object H 2356-309  

E-print Network

Weak spectral features in BL Lacertae objects (BL Lac) often provide a unique opportunity to probe the inner region of this rare type of active galactic nucleus. We present a Hubble Space Telescope/Cosmic Origins Spectrograph observation of the BL Lac H 2356-309. A weak Ly$\\alpha$ emission line was detected. This is the fourth detection of a weak Ly$\\alpha$ emission feature in the ultraviolet (UV) band in the so-called "high energy peaked BL Lacs", after Stocke et al. Assuming the line-emitting gas is located in the broad line region (BLR) and the ionizing source is the off-axis jet emission, we constrain the Lorentz factor ($\\Gamma$) of the relativistic jet to be $\\geq 8.1$ with a maximum viewing angle of 3.6$^\\circ$. The derived $\\Gamma$ is somewhat larger than previous measurements of $\\Gamma \\approx 3 - 5$, implying a covering factor of $\\sim$ 3% of the line-emitting gas. Alternatively, the BLR clouds could be optically thin, in which case we constrain the BLR warm gas to be $\\sim 10^{-5}\\rm\\ M_{\\odot}$. ...

Fang, Taotao; Buote, David A; Stocke, John T; Shull, J Michael; Canizares, Claude R; Gastaldello, Fabio

2014-01-01

245

An HST/COS Observation of Broad Ly? Emission and Associated Absorption Lines of the BL Lacertae Object H 2356-309  

NASA Astrophysics Data System (ADS)

Weak spectral features in BL Lacertae objects (BL Lacs) often provide a unique opportunity to probe the inner region of this rare type of active galactic nucleus. We present a Hubble Space Telescope/Cosmic Origins Spectrograph observation of the BL Lac H 2356-309. A weak Ly? emission line was detected. This is the fourth detection of a weak Ly? emission feature in the ultraviolet (UV) band in the so-called high-energy peaked BL Lacs, after Stocke et al. Assuming the line-emitting gas is located in the broad line region (BLR) and the ionizing source is the off-axis jet emission, we constrain the Lorentz factor (?) of the relativistic jet to be >=8.1 with a maximum viewing angle of 3.°6. The derived ? is somewhat larger than previous measurements of ? ? 3-5, implying a covering factor of ~3% of the line-emitting gas. Alternatively, the BLR clouds could be optically thin, in which case we constrain the BLR warm gas to be ~10–5 M ?. We also detected two H I and one O VI absorption lines that are within |?v| < 150 km s–1 of the BL Lac object. The O VI and one of the H I absorbers likely coexist due to their nearly identical velocities. We discuss several ionization models and find a photoionization model where the ionizing photon source is the BL Lac object that can fit the observed ion column densities with reasonable physical parameters. This absorber can either be located in the interstellar medium of the host galaxy or in the BLR.

Fang, Taotao; Danforth, Charles W.; Buote, David A.; Stocke, John T.; Shull, J. Michael; Canizares, Claude R.; Gastaldello, Fabio

2014-11-01

246

Broadly cross-reactive HIV-1-neutralizing human monoclonal Fab selected for binding to gp120-CD4-CCR5 complexes  

PubMed Central

HIV-1 entry into cells involves formation of a complex between gp120 of the viral envelope glycoprotein (Env), a receptor (CD4), and a coreceptor, typically CCR5. Here we provide evidence that purified gp120JR-FL–CD4–CCR5 complexes exhibit an epitope recognized by a Fab (X5) obtained by selection of a phage display library from a seropositive donor with a relatively high broadly neutralizing serum antibody titer against an immobilized form of the trimolecular complex. X5 bound with high (nM) affinity to a variety of Envs, including primary isolates from different clades and Envs with deleted variable loops (V1, -2, -3). Its binding was significantly increased by CD4 and slightly enhanced by CCR5. X5 inhibited infection of peripheral blood mononuclear cells by a selection of representative HIV-1 primary isolates from clades A, B, C, D, E, F, and G with an efficiency comparable to that of the broadly neutralizing antibody IgG1 b12. Furthermore, X5 inhibited cell fusion mediated by Envs from R5, X4, and R5X4 viruses. Of the five broadly cross-reactive HIV-1-neutralizing human monoclonal antibodies known to date, X5 is the only one that exhibits increased binding to gp120 complexed with receptors. These findings suggest that X5 could possibly be used as entry inhibitor alone or in combination with other antiretroviral drugs for the treatment of HIV-1-infected individuals, provide evidence for the existence of conserved receptor-inducible gp120 epitopes that can serve as targets for potent broadly cross-reactive neutralizing antibodies in HIV-1-infected patients, and have important conceptual and practical implications for the development of vaccines and inhibitors. PMID:11997472

Moulard, Maxime; Phogat, Sanjay K.; Shu, Yuuei; Labrijn, Aran F.; Xiao, Xiaodong; Binley, James M.; Zhang, Mei-Yun; Sidorov, Igor A.; Broder, Christopher C.; Robinson, James; Parren, Paul W. H. I.; Burton, Dennis R.; Dimitrov, Dimiter S.

2002-01-01

247

The Broad-Lined Type Ic SN 2012ap and the Nature of Relativistic Supernovae Lacking a Gamma-ray Burst Detection  

E-print Network

We present ultraviolet, optical, and near-infrared observations of SN 2012ap, a broad-lined Type Ic supernova in the galaxy NGC 1729 that produced a relativistic and rapidly decelerating outflow without a gamma-ray burst signature. Photometry and spectroscopy follow the flux evolution from -13 to +272 days past the B-band maximum of -17.4 +/- 0.5 mag. The spectra are dominated by Fe II, O I, and Ca II absorption lines at ejecta velocities of 20,000 km/s that change slowly over time. Other spectral absorption lines are consistent with contributions from photospheric He I, and hydrogen may also be present at higher velocities (> 27,000 km/s). We use these observations to estimate explosion properties and derive a total ejecta mass of 2.7 Msolar, a kinetic energy of 1.0x10^{52} erg, and a 56Ni mass of 0.1-0.2 Msolar. Nebular spectra (t > 200d) exhibit an asymmetric double-peaked [OI] 6300,6364 emission profile that we associate with absorption in the supernova interior, although toroidal ejecta geometry is an al...

Milisavljevic, D; Parrent, J T; Soderberg, A M; Fesen, R A; Mazzali, P; Maeda, K; Sanders, N E; Cenko, S B; Silverman, J M; Filippenko, A V; Kamble, A; Chakraborti, S; Drout, M R; Kirshner, R P; Pickering, T E; Kawabata, K; Hattori, T; Hsiao, E Y; Stritzinger, M D; Marion, G H; Vinko, J; Wheeler, J C

2014-01-01

248

The Real Meaning of Complex Minkowski-Space World-Lines  

E-print Network

In connection with the study of shear-free null geodesics in Minkowski space, we investigate the real geometric effects in real Minkowski space that are induced by and associated with complex world-lines in complex Minkowski space. It was already known, in a formal manner, that complex analytic curves in complex Minkowski space induce shear-free null geodesic congruences. Here we look at the direct geometric connections of the complex line and the real structures. Among other items, we show, in particular, how a complex world-line projects into the real Minkowski space in the form of a real shear-free null geodesic congruence.

T. M. Adamo; E. T. Newman

2009-11-21

249

Discovery of a broad O VIII Ly alpha line in the ultra-compact X-ray binary 4U 1543-624  

E-print Network

We report the discovery of a broad emission feature at ~0.7 keV in the spectra of the ultra-compact 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 alpha 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 keV and ~6.6 keV as O VIII Ly alpha and Fe K alpha emission respectively, caused by X-rays reflected off the accretion disc in the strong gravitational field close to the accretor.

Madej, O K

2010-01-01

250

A multi-epoch study of the C IV absorption variability in the broad absorption line quasar APM 08279+5255  

NASA Astrophysics Data System (ADS)

Broad absorption line (BAL) variability potentially represents a powerful tool to investigate the physical nature and the structure of gas outflows in active galactic nuclei. Most existing BAL variability studies rely on observations taken at a few epochs for samples of tens of BAL QSOs. In this study we present the first “monitoring” of a single object, APM 08279+5255, which has been observed more than 20 times since 2003. All available spectra from the literature have also been analysed, including two high resolution spectra, extending the time interval from 1998 to 2012. A relative stability of the shape of the absorption profile is found. At the same time significant variations of the equivalent width are observed. A correlation of the BAL equivalent width with the QSO luminosity is found for the first time. These results suggest that changes in the ionisation state of the gas are causing opacity changes.

Saturni, F. G.; Trevese, D.; Vagnetti, F.; Perna, M.

2014-10-01

251

Seyfert galaxy ultraviolet emission-line intensities and variability - A self-consistent photoionization analysis applied to broad-line-emitting gas in NGC 3783  

NASA Technical Reports Server (NTRS)

Well-constrained photoionization models for the Seyfert I galaxy NGC 3783 are developed. Both cross-correlation analyses and line variability trends with varying ionizing radiation flux require a multicomponent picture. All the data for He II 1640 A, C IV 1549 A, and semiforbidden C III 1909 A can be reasonably well reproduced by two cloud components. One has a source-cloud distance of 24 lt-days, gas density around 3 x 10 exp 10/cu cm, ionization parameter range of 0.04-0.2, and cloud thickness such that about half of the carbon is doubly ionized and about half is triply ionized. The other component is located approximately 96 lt-days from the source, is shielded from the source by the inner cloud, has a density about 3 x 10 to the 9th/cu cm, and is characterized by an ionization parameter range of 0.001-0.03, The cloud thickness is such that about 45 percent carbon is doubly ionized and about 55 percent is singly ionized.

Koratkar, Anuradha P.; Macalpine, Gordon M.

1992-01-01

252

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

253

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

254

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

255

Ultrasound Based In-Line Rheometry of Complex Fluids  

NASA Astrophysics Data System (ADS)

A method for in-line rheometry combining the Doppler-based Ultrasound Velocity Profiling (UVP) technique with Pressure Difference (PD) measurements, commonly known as UVP-PD, has recently been developed. It has advantages over commercially available process rheometers and off-line instruments in being non-invasive, applicable to opaque and concentrated suspensions containing large particles and giving radial velocity profiles and rheological parameters, e.g. yield stress in real-time. The UVP-PD methodology and system developed at SIK has been successfully applied to a range of model and industrial fluids and suspensions, including fluids containing large particles and fibers. UVP-PD can be used to monitor rapid industrial unit operations such as start-up or shutdown of the process, liquid displacements during rinsing or product change and in-line mixing. It is also an interesting option for real-time in-line process monitoring and control.

Wiklund, Johan; Stading, Mats

2008-07-01

256

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. PMID:24260102

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

257

Complexity cost analysis in a large product line  

E-print Network

Hewlett-Packard's Industry Standard Servers (ISS) organization offers a large variety of server computers and accessories. The large range of options available to its customers gives way to complex processes and less than ...

Landivar Chávez, José Luis

2006-01-01

258

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

259

A Vaccine Based on the Rhesus Cytomegalovirus UL128 Complex Induces Broadly Neutralizing Antibodies in Rhesus Macaques  

PubMed Central

Neutralizing antibodies (NAb) are important for interfering with horizontal transmission of human cytomegalovirus (HCMV) leading to primary and congenital HCMV infection. Recent findings have shown that a pentameric virion complex formed by the glycoproteins gH/gL, UL128, UL130, and UL131A (UL128C) is required for HCMV entry into epithelial/endothelial cells (Epi/EC) and is the target of potent NAb in HCMV-seropositive individuals. Using bacterial artificial chromosome technology, we have generated a modified vaccinia Ankara virus (MVA) that stably coexpresses all 5 rhesus CMV (RhCMV) proteins homologous to HCMV UL128C, termed MVA-RhUL128C. Coimmunoprecipitation confirmed the interaction of RhgH with the other 4 RhCMV subunits of the pentameric complex. All 8 RhCMV-naïve rhesus macaques (RM) vaccinated with MVA-RhUL128C developed NAb that blocked infection of monkey kidney epithelial cells (MKE) and rhesus fibroblasts. NAb titers induced by MVA-RhUL128C measured on both cell types at 2 to 6 weeks postvaccination were comparable to levels observed in naturally infected RM. In contrast, MVA expressing a subset of RhUL128C proteins or RhgB glycoprotein only minimally stimulated NAb that inhibited infection of MKE. In addition, following subcutaneous RhCMV challenge at 8 weeks postvaccination, animals vaccinated with MVA-RhUL128C showed reduced plasma viral loads. These results indicate that MVA expressing the RhUL128C induces NAb inhibiting RhCMV entry into both Epi/EC and fibroblasts and limits RhCMV replication in RM. This novel approach is the first step in developing a prophylactic HCMV vaccine designed to interfere with virus entry into major cell types permissive for viral replication, a required property of an effective vaccine. PMID:23152525

Wussow, Felix; Yue, Yujuan; Martinez, Joy; Deere, Jesse D.; Longmate, Jeff; Herrmann, Andreas

2013-01-01

260

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

261

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

262

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

263

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

264

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  

Microsoft Academic Search

We present the final installment of an intensive 13 year study of variations of the optical continuum and broad Hbeta emission line in the Seyfert 1 galaxy NGC 5548. The database consists of 1530 optical continuum measurements and 1248 Hbeta measurements. The Hbeta variations follow the continuum variations closely, with a typical time delay of about 20 days. However, a

B. M. Peterson; P. Berlind; R. Bertram; K. Bischoff; N. G. Bochkarev; N. Borisov; A. N. Burenkov; M. Calkins; L. Carrasco; V. H. Chavushyan; R. Chornock; M. Dietrich; V. T. Doroshenko; O. V. Ezhkova; A. V. Filippenko; A. M. Gilbert; J. P. Huchra; W. Kollatschny; D. C. Leonard; W. Li; V. M. Lyuty; Yu. F. Malkov; T. Matheson; N. I. Merkulova; V. P. Mikhailov; M. Modjaz; C. A. Onken; R. W. Pogge; V. I. Pronik; B. Qian; P. Romano; S. G. Sergeev; E. A. Sergeeva; A. I. Shapovalova; O. I. Spiridonova; J. Tao; S. Tokarz; J. R. Valdes; V. V. Vlasiuk; R. M. Wagner; B. J. Wilkes

2002-01-01

265

Complex Singular Points of the Tie-Line Vector Field Diagrams of Ternary Mixtures  

Microsoft Academic Search

Complex singular points of the tie-line vector field diagrams of liquid-vapor ternary systems are considered in terms of the theory of stationary vector fields and bifurcation theory. These complex singular points are found to be tangential azeotropic points of different orders, which play a decisive role in transformations of the diagrams of heterogeneous mixtures.

L. A. Serafimov; T. V. Chelyuskina

2005-01-01

266

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

SciTech Connect

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

Parkhomenko, S. E., E-mail: spark@itp.ac.ru [Landau Institute for Theoretical Physics (Russian Federation)

2012-01-15

267

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 Astrophysics Data System (ADS)

We present the final installment of an intensive 13 year study of variations of the optical continuum and broad H? emission line in the Seyfert 1 galaxy NGC 5548. The database consists of 1530 optical continuum measurements and 1248 H? measurements. The H? 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~L1/2ion. Moreover, the apparently linear nature of the correlation between the H? response time and the nonstellar optical continuum Fopt arises as a consequence of the changing shape of the continuum as it varies, specifically Fopt~F0.56UV.

Peterson, B. M.; Berlind, P.; Bertram, R.; Bischoff, K.; Bochkarev, N. G.; Borisov, N.; Burenkov, A. N.; Calkins, M.; Carrasco, L.; Chavushyan, V. H.; Chornock, R.; Dietrich, M.; Doroshenko, V. T.; Ezhkova, O. V.; Filippenko, A. V.; Gilbert, A. M.; Huchra, J. P.; Kollatschny, W.; Leonard, D. C.; Li, W.; Lyuty, V. M.; Malkov, Yu. F.; Matheson, T.; Merkulova, N. I.; Mikhailov, V. P.; Modjaz, M.; Onken, C. A.; Pogge, R. W.; Pronik, V. I.; Qian, B.; Romano, P.; Sergeev, S. G.; Sergeeva, E. A.; Shapovalova, A. I.; Spiridonova, O. I.; Tao, J.; Tokarz, S.; Valdes, J. R.; Vlasiuk, V. V.; Wagner, R. M.; Wilkes, B. J.

2002-12-01

268

Electromagnetic Dipole Radiation Fields, Shear-Free Congruences and Complex Center of Charge World Lines  

E-print Network

We show that for asymptotically vanishing Maxwell fields in Minkowski space with non-vanishing total charge, one can find a unique geometric structure, a null direction field, at null infinity. From this structure a unique complex analytic world-line in complex Minkowski space that can be found and then identified as the complex center of charge. By ''sitting'' - in an imaginary sense, on this world-line both the (intrinsic) electric and magnetic dipole moments vanish. The (intrinsic) magnetic dipole moment is (in some sense) obtained from the `distance' the complex the world line is from the real space (times the charge). This point of view unifies the asymptotic treatment of the dipole moments For electromagnetic fields with vanishing magnetic dipole moments the world line is real and defines the real (ordinary center of charge). We illustrate these ideas with the Lienard-Wiechert Maxwell field. In the conclusion we discuss its generalization to general relativity where the complex center of charge world-line has its analogue in a complex center of mass allowing a definition of the spin and orbital angular momentum - the analogues of the magnetic and electric dipole moments.

Carlos N. Kozameh; Ezra T. Newman

2005-04-20

269

Cytotoxic Effects of Newly Synthesized Palladium(II) Complexes of Diethyldithiocarbamate on Gastrointestinal Cancer Cell Lines  

PubMed Central

As a part of a drug development program to discover novel therapeutic and more effective palladium (Pd) based anticancer drugs, a series of water-soluble Pd complexes have been synthesized by interaction between [Pd (phen)(H2O)2(NO3)2] and alkylenebisdithiocarbamate(al-bis-dtc) disodium salts. This study was undertaken to examine the possible cytotoxic effect of three novel complexes (0.125–64?µg/mL) on human gastric carcinoma (AGS), esophageal squamous cell carcinoma (Kyse-30), and hepatocellular carcinoma (HepG2) cell lines. The cytotoxicity was examined using cell proliferation and acridine orange/ethidium bromide (AO/EB) assay. In order to examine the effects of new Pd(II) complexes on cell cycle status, we performed cell cycle analysis. The complexes were found to have completely lethal effects on the cell lines, and the half maximal inhibitory concentration (IC50) values obtained for the cell lines were much lower in comparison with cisplatin. We demonstrated that the three new Pd(II) complexes are able to induce G2/M phase arrest in AGS and HepG2; in addition, the Pd(II) complexes caused an S phase arrest in Kyse-30 cell line. Our results indicate that newly synthesized Pd(II) complexes may provide a novel class of chemopreventive compounds for anticancer therapy. PMID:25147738

Hadizadeh, Shahram; Najafzadeh, Nowruz; Mazani, Mohammad; Mansouri-Torshizi, Hassan; Niapour, Ali

2014-01-01

270

Broad coverage identification of multiple proteolytic cleavage site sequences in complex high molecular weight proteins using quantitative proteomics as a complement to edman sequencing.  

PubMed

Proteolytic processing modifies the pleiotropic functions of many large, complex, and modular proteins and can generate cleavage products with new biological activity. The identification of exact proteolytic cleavage sites in the extracellular matrix laminins, fibronectin, and other extracellular matrix proteins is not only important for understanding protein turnover but is needed for the identification of new bioactive cleavage products. Several such products have recently been recognized that are suggested to play important cellular regulatory roles in processes, including angiogenesis. However, identifying multiple cleavage sites in extracellular matrix proteins and other large proteins is challenging as N-terminal Edman sequencing of multiple and often closely spaced cleavage fragments on SDS-PAGE gels is difficult, thus limiting throughput and coverage. We developed a new liquid chromatography-mass spectrometry approach we call amino-terminal oriented mass spectrometry of substrates (ATOMS) for the N-terminal identification of protein cleavage fragments in solution. ATOMS utilizes efficient and low cost dimethylation isotopic labeling of original N-terminal and proteolytically generated N termini of protein cleavage fragments followed by quantitative tandem mass spectrometry analysis. Being a peptide-centric approach, ATOMS is not dependent on the SDS-PAGE resolution limits for protein fragments of similar mass. We demonstrate that ATOMS reliably identifies multiple proteolytic sites per reaction in complex proteins. Fifty-five neutrophil elastase cleavage sites were identified in laminin-1 and fibronectin-1 with 34 more identified by matrix metalloproteinase cleavage. Hence, our degradomics approach offers a complimentary alternative to Edman sequencing with broad applicability in identifying N termini such as cleavage sites in complex high molecular weight extracellular matrix proteins after in vitro cleavage assays. ATOMS can therefore be useful in identifying new cleavage products of extracellular matrix proteins cleaved by proteases in pathology for bioactivity screening. PMID:20876890

Doucet, Alain; Overall, Christopher M

2011-05-01

271

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

272

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

PubMed Central

Protein complexes are a cornerstone of many biological processes and together they form various types of molecular machinery. A broad understanding of these protein complexes is crucial for revealing and building models of protein function and regulation. Pancreatic cancer is a highly lethal disease which is difficult to diagnose at early stage and even more difficult to cure. In this study, we applied a gradient clear native gel system combined with subsequent second-dimensional SDS-PAGE to separate protein complexes from cell lysates of SW1990 and PANC-1 pancreatic cancer cell lines with different degrees of differentiation. Ten heat-shock-protein- (HSP-) associated protein complexes were separated and identified, and the differentially expressed proteins related to cancers were also found, such as HSP60, protein disulfide-isomerase A4 (ERp72), and transitional endoplasmic reticulum ATPase (TER ATPase). PMID:22028587

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

2011-01-01

273

Separation and identification of HSP-associated protein complexes from pancreatic cancer cell lines using 2D CN/SDS-PAGE coupled with mass spectrometry.  

PubMed

Protein complexes are a cornerstone of many biological processes and together they form various types of molecular machinery. A broad understanding of these protein complexes is crucial for revealing and building models of protein function and regulation. Pancreatic cancer is a highly lethal disease which is difficult to diagnose at early stage and even more difficult to cure. In this study, we applied a gradient clear native gel system combined with subsequent second-dimensional SDS-PAGE to separate protein complexes from cell lysates of SW1990 and PANC-1 pancreatic cancer cell lines with different degrees of differentiation. Ten heat-shock-protein- (HSP-) associated protein complexes were separated and identified, and the differentially expressed proteins related to cancers were also found, such as HSP60, protein disulfide-isomerase A4 (ERp72), and transitional endoplasmic reticulum ATPase (TER ATPase). PMID:22028587

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

2011-01-01

274

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. PMID:24059435

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

2013-01-01

275

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

NASA Astrophysics Data System (ADS)

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

Wiramihardja, S. D.; Kogure, T.

276

Evaluation of novel trans-sulfonamide platinum complexes against tumor cell lines.  

PubMed

Platinum-based drugs, mainly cisplatin, are employed for the treatment of solid malignancies. However, cisplatin treatment often results in the development of chemoresistance, leading to therapeutic failure. Here, the antitumor activity of different trans-sulfonamide platinum complexes in a panel of human cell lines is presented. The cytotoxicity profiles and cell cycle analyses of these platinum sulfonamide complexes were different from those of cisplatin. These studies showed that complex 2b with cyclohexyldiamine and dansyl moieties had the best antitumoral activities. PMID:24589491

Pérez, Carlos; Díaz-García, C Vanesa; Agudo-López, Alba; del Solar, Virginia; Cabrera, Silvia; Agulló-Ortuño, M Teresa; Navarro-Ranninger, Carmen; Alemán, José; López-Martín, José A

2014-04-01

277

Two improved methods for determining complex permittivity in coaxial line of powder materials  

NASA Astrophysics Data System (ADS)

In this paper, two improved methods are proposed for determining the complex permittivity of the powder materials from 1 to 18 GHz. Unlike the measurements of solid materials in a two-port coaxial line, two Teflon annular spacers are used to house the powder materials. One method is to obtain the scattering parameters at the reference plane of the powder materials using an improved TRL calibration method, then reconstruct the complex permittivity based on the traditional transmission-line method. The other method is based on the measurements of the scattering parameters of two different length coaxial lines, which only loaded with two Teflon annular spacers or partially loaded with powder materials housed by two Teflon annular spacers. Those two methods are particularly suitable for a small amount of powder materials. Finally the results of the measurements of two powder materials: loess and thin sand are shown, compared with the results measured by Agilent's 85070E dielectric probe kit.

Zha, Haihui; Tong, Ling; Tian, Yu; Gao, Bo

2013-01-01

278

Macrophage cell lines derived from major histocompatibility complex II-negative mice  

NASA Technical Reports Server (NTRS)

Two bone-marrow-derived macrophage cell lines, C2D and C2Dt, were isolated from major histocompatibility class II negative knock-out mice. The C2D cell line was stabilized by continuous culture in colony-stimulating factor-1 and the C2Dt cell line was transformed with SV40 virus large T antigen. These cells exhibited phenotypic properties of macrophages including morphology and expression of Mac 1 and Mac 2 cell surface molecules. These cells also had comparable growth to the bone-marrow-derived macrophage cell line B6MP102. These new cell lines were not spontaneously cytotoxic and were only capable of modest killing of F5b tumor cells when stimulated with LPS and interferon-gamma, but not when stimulated with LPS alone or with staphylococcal exotoxin. C2D and C2Dt cells phagocytosed labeled Staphylococcus aureus similarly to B6MP102 cells but less well than C2D peritoneal macrophages. These cell lines secreted interleukin-6, but not tumor necrosis factor or nitric oxide in response to LPS or staphlococcal enterotoxins A or B C2D(t) cells were tumorigenic in C2D and C57BL/6J mice but C2D cells were not. These data suggest that macrophage cell lines can be established from bone marrow cells of major histocompatibility complex II-negative mice.

Beharka, A. A.; Armstrong, J. W.; Chapes, S. K.; Spooner, B. S. (Principal Investigator)

1998-01-01

279

3 mm spectral line survey of two lines of sight toward two typical cloud complexes in the Galactic Center  

E-print Network

We present the results of two Mopra 3-mm spectral line surveys of the Lines of Sight (LOS) toward the Galactic Center (GC) molecular complexes Sgr B2 (LOS+0.693) and Sgr A (LOS-0.11). The spectra covered the frequency ranges of ~77-93 GHz and ~105-113 GHz. We have detected 38 molecular species and 25 isotopologues. The isotopic ratios derived from column density ratios are consistent with the canonical values, indicating that chemical isotopic fractionation and/or selective photodissociation can be considered negligible (<10%) for the GC physical conditions. The derived abundance and rotational temperatures are very similar for both LOSs, indicating very similar chemical and excitation conditions for the molecular gas in the GC. The excitation conditions are also very similar to those found for the nucleus of the starburst galaxy NGC 253. We report for the first time the detection of HCO and HOC+ emission in LOS+0.693. Our comparison of the abundance ratios between CS, HCO, HOC+ and HCO+ found in the two L...

Armijos-Abendaño, J; Requena-Torres, M A; Martín, S; Rodríguez-Franco, A

2014-01-01

280

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

PubMed

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

Redding, W Rich; O'Grady, Stephen E

2012-08-01

281

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. PMID:24466371

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

282

Investigation of dark line defects induced by catastrophic optical damage in broad-area AlGaInP laser diodes  

Microsoft Academic Search

The authors present a detailed investigation of defects generated during catastrophic optical damage (COD) in high-power 650 nm AlGaInP lasers using microphotoluminescence (mu-PL) mapping, focused ion beam (FIB) microscopy, and deep-etching techniques. High-resolution mu-PL images demonstrated that during COD, nonradiative dark line defects (DLDs) originate from the front mirror of the laser and propagate in several branches into the laser

M. Bou Sanayeh; A. Jaeger; W. Schmid; S. Tautz; P. Brick; K. Streubel; G. Bacher

2006-01-01

283

Investigation of dark line defects induced by catastrophic optical damage in broad-area AlGaInP laser diodes  

NASA Astrophysics Data System (ADS)

The authors present a detailed investigation of defects generated during catastrophic optical damage (COD) in high-power 650nm AlGaInP lasers using microphotoluminescence (?-PL) mapping, focused ion beam (FIB) microscopy, and deep-etching techniques. High-resolution ?-PL images demonstrated that during COD, nonradiative dark line defects (DLDs) originate from the front mirror of the laser and propagate in several branches into the laser perpendicular to the output facet. Furthermore, FIB microscopy identified the epitaxial layers affected by COD, revealing that DLDs are confined to the active region. In addition, deep etching confirmed that these defects have a noncrystalline nature.

Bou Sanayeh, M.; Jaeger, A.; Schmid, W.; Tautz, S.; Brick, P.; Streubel, K.; Bacher, G.

2006-09-01

284

TRIFL: A design tool for modeling complex magnetically insulated transmission line geometries  

SciTech Connect

Vacuum power flow in modern high-power pulsed accelerator transmission lines requires field stresses at the conductors that are so high that negative surfaces become space-charge-limited electron emitters. The performance of these lines can be calculated using two- and three-dimensional, time-dependent, particle-in-cell electromagnetic codes such a TWOQUICK and QUICKSILVER. Extensive design of complex systems using these simulation codes would be extremely expensive and, perhaps, impossible for many of the new pulsed power systems being planned. An analytic model has been developed which predicts the behavior of magnetically insulated transmission lines. The model uses flow impedance parameters with an expanded set of Telegrapher`s equations to calculate radial currents in the transmission lines. This model has been implemented in a code, TRIFL (TRIple-equation-FLow model), on workstations and PC`s and allows one to do detailed designed studies on systems far too complex for similar treatment using a PIC code. TRIFL has been used to design hardware for the PBFA-X accelerator and to analyze PBFA-X data.

Mix, L.P.; Mendel, C.W. Jr.; Seidel, D.B.; Rosenthal, S.E. [Sandia National Labs. Albuquerque, NM (United States)

1996-12-31

285

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

286

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

287

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

288

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

289

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

290

The origin of the iron line complex in the reflection-less Seyfert 1 galaxy NGC7213  

NASA Astrophysics Data System (ADS)

We propose to observe with Chandra ACIS-S HETG the Seyfert 1 Galaxy NGC 7213 for 150 ks. The source is without a detectable Compton reflection component, but has a neutral iron line with EW~80 eV, suggesting an origin in Compton-thin matter like the BLR. Ionizer iron emission features have also been revealed. The aim of the proposed observation is twofold: a) to measure in detail the neutral iron line width and check whether it is consistent with that of the optical broad lines. b) to confirm the presence of the two ionized lines. To better compare X-ray and BLR line widths, we propose a coordinated optical spectroscopic observation of NGC 7213 with the CTIO 4-m.

Matt, Giorgio

2006-09-01

291

Unraveling the Mysteries of Complex Interstellar Organic Chemistry Using Herschel/hifi Spectral Line Surveys  

NASA Astrophysics Data System (ADS)

The goal of our ongoing Herschel Space Observatory OT1 program is to probe the influence of physical environment on molecular complexity through spectral line surveys. These observations target a sample of 10 sources, probe a range of physical environments, and include frequency windows that contain transitions from a set of known complex organic molecules. From these results, we have determined the fractional abundances of a set of organic molecules that are predicted by models to trace key chemical mechanisms in interstellar clouds. We are examining correlations between classes of molecules, as well as correlations between the physical properties of the source (i.e. temperature, density, age, etc.) and each molecular target. These results can be used as benchmarks 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. Here we will report on preliminary results from these observations and discuss these results in the context of the effect that physical environment has on the chemical complexity of interstellar clouds.

Wang, Shiya; Radhuber, Mary L.; Laas, Jacob C.; Kroll, Jay A.; Sanders, James L.; Weaver, Susanna L. Widicus; Lis, Dariusz C.; Herbst, Eric

2012-06-01

292

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

PubMed

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

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

2013-06-01

293

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. PMID:23439634

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

2013-01-01

294

SPECIAL ISSUE DEVOTED TO THE 90TH ANNIVERSARY OF A.M. PROKHOROV: High-resolution line-shape spectroscopy during a laser pulse based on Dual-Broad-Band—CARS interferometry  

NASA Astrophysics Data System (ADS)

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 ?0.1 cm-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.

Vereschagin, Konstantin A.; Vereschagin, Alexey K.; Clauss, W.; Klimenko, D. N.; Oschwald, M.; Smirnov, Valery V.; Stelmakh, O. M.; Fabelinskii, V. I.

2006-07-01

295

Broken Rotor Bar Detection in Line-Fed Induction Machines Using Complex Wavelet Analysis of Startup Transients  

Microsoft Academic Search

Fault detection of line-connected induction machines using complex vector wavelets to analyze the transient stator currents during startup is proposed in this paper. When a machine is connected to the line, the startup transient is characterized by large stator (and rotor) currents as well as by large slips (i.e., the rotor speed is significantly smaller than the excitation frequency). The

Fernando Briz; Michael W. Degner; Pablo Garcia; David Bragado

2008-01-01

296

The Mount Manengouba, a complex volcano of the Cameroon Line:1 Volcanic history, petrological and geochemical features2  

E-print Network

1 The Mount Manengouba, a complex volcano of the Cameroon Line:1 Volcanic history, petrological 24 Keywords: Cameroon Volcanic Line, Manengouba volcano, alkaline magmatism, Quaternary25 volcanism is related to four chronological stages: 1) forming31 of the early Manengouba shield volcano between 1

Boyer, Edmond

297

SUBARU HIGH-RESOLUTION SPECTROSCOPY OF COMPLEX METAL ABSORPTION LINES OF THE QUASAR HS 1603+38201  

E-print Network

SUBARU HIGH-RESOLUTION SPECTROSCOPY OF COMPLEX METAL ABSORPTION LINES OF THE QUASAR HS 1603-resolution spectrum of the quasar HS 1603+3820 (zem = 2.542), observed with the High Dispersion Spectrograph on the Subaru Telescope. This quasar, first discovered in the Hamburg/CfA Quasar Survey, has 11 C iv lines at 1

Iye, Masanori

298

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

299

Lines  

ERIC Educational Resources Information Center

National Geography Standards for the middle school years generally stress the teaching of latitude and longitude. There are many creative ways to explain the great grid that encircles our planet, but the author has found that students in his college-level geography courses especially enjoy human-interest stories associated with lines of latitude…

Mires, Peter B.

2006-01-01

300

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

E-print Network

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

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

1997-09-20

301

The 2010 Broad Prize  

ERIC Educational Resources Information Center

A new data analysis, based on data collected as part of The Broad Prize process, provides insights into which large urban school districts in the United States are doing the best job of educating traditionally disadvantaged groups: African-American, Hispanics, and low-income students. Since 2002, The Eli and Edythe Broad Foundation has awarded The…

Education Digest: Essential Readings Condensed for Quick Review, 2011

2011-01-01

302

Modeling of the broad band X-ray spectra of the Seyfert Mrk 841  

NASA Astrophysics Data System (ADS)

The presence in Mrk 841 of a strong soft excess and a complex iron profile, has been confirmed by repeated XMM-Newton observations. The 0.5-10 keV emission may be entirely explained by the combination of a relativistically blurred photoionized reflection, producing simultaneously the soft excess and the broad iron line, and a neutral, unblurred one, producing the narrow line.

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

2008-04-01

303

The iron K line complex in NGC1068: implications for X-ray reflection in the nucleus  

E-print Network

We report a new analysis of ASCA data on the iron K line complex in NGC1068. The line complex basically consists of three components, as previously reported. A weak red wing of the 6.4 keV fluoresence iron K line is found. A plausible explanation is Compton scattering in optically thick, cold matter which can be identified with an obscuring torus or cold gas in the host galaxy. We also show that this `Compton shoulder' should be observable with ASCA using a simulated reflection spectrum. In order to explain the two higher energy lines as well as the cold 6.4 keV line, we fit the ASCA data with a composite model of cold and warm reflection. This shows that cold reflection dominates the observed X-ray emission above 4 keV. The two higher energy lines have large equivalent width with respect to the warm-scattered continuum, suggesting that efficient resonant scattering operates. The line energies are systematically lower than those expected from resonant lines for FeXXV and FeXXVI by 100 eV. The redshifts may be due to either the ionized gas of the warm mirror receding at a radial velocity of 4000-5000 km/s, or effects of Compton scattering in a complicated geometry.

K. Iwasawa; A. C. Fabian; G. Matt

1997-03-25

304

Replacing reverse line blot hybridization spoligotyping of the Mycobacterium tuberculosis complex.  

PubMed

Spoligotyping is a tool for the molecular characterization/typing of Mycobacterium tuberculosis complex (MTBC) strains based on target sequences (spacers) in the direct repeat (DR) region (14). The standard spoligotyping assay involves the hybridization of amplified sample DNA to nylon membrane-immobilized oligonucleotides whose sequences are representative of 43 spacer regions. Variations in the number of spacers as a result of deletions of adjacent blocks of repetitive units allow the differentiation of clinical isolates. In the present study, we developed a new multiplexed primer extension-based spoligotyping assay using automated matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) that improves the classical reverse line blot hybridization assay with respect to reproducibility, throughput, process flow, ease of use, and data analysis. Validation of the MALDI-TOF MS-based spoligotyping assay with two sample sets with a total of 326 samples resulted in 96.6% concordance (315/326) when the full spoligotype patterns were compared with the results of standard spoligotyping and 99.9% concordance when the results were compared with those of individual primer extension assays. Ten strains (including two Mycobacterium canettii strains) showed discordant results with one or two spacer differences from the membrane-based spoligotyping result. Most discordant samples were identified to be the result of ambiguities in the interpretation of weak hybridization signals in the reverse line blot assay and sequence variations in the spacer regions. We established a new automated primer extension assay and successfully validated it for use for the routine typing of MTBC strains in the research and public health laboratory environments. The present multiplex levels of up to 30 are extendable and allow the additional incorporation of controls and antibiotic resistance markers. PMID:20200291

Honisch, Christiane; Mosko, Michael; Arnold, Catherine; Gharbia, Saheer E; Diel, Roland; Niemann, Stefan

2010-05-01

305

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

306

The Effects of Pre-Task Planning and On-line Planning on Fluency, Complexity, and Accuracy in L2 Monologic Oral Production.  

ERIC Educational Resources Information Center

Investigated the effects of both pre-task and on-line planning on second language (L2) oral production. Results show that pre-task planning enhances grammatical complexity while on-line planning positively influences accuracy and grammatical complexity. Pre-task planners also produced more fluent and lexically varied language than the on-line

Yuan, Fangyuan; Ellis, Rod

2003-01-01

307

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

308

Disentangling the complexity of infectious diseases: Time is ripe to improve the first-line statistical toolbox for epidemiologists.  

PubMed

Because many biological processes related to the dynamics of infectious diseases are caused by complex interactions between the environment, the host(s) and the agent(s), the necessity to address the methodological implications of this inherent complexity has recently emerged in epidemiology. Most epidemiologists now acknowledge that most human infectious diseases are likely to have complex dynamics. However, this knowledge still percolates with difficulty in their statistical "modus operandi". Indeed, for the study of complex systems, the traditional first-line statistical toolbox of epidemiologists (mainly built around the Generalized Linear Model family), despite its undeniable practicality and robustness, has structural limitations deprecating its usefulness. Three major sources of complexity neglected or not taken into account by this first-line statistical toolbox and having deep statistical implications are the multi-level organization of data, the non-linear relationships between variables and the complex interactions between variables. Three promising candidates to incorporate along with traditional tools for a new first-line statistical toolbox more suitable to apprehend these sources of complexity are the generalized linear mixed models, the generalized additive models, and the structural equation models. The aforementioned methodologies have the advantage to be generalizations of GLM models and are relatively easy to implement. Their assimilation and implementation would thus be greatly facilitated for epidemiologists. More globally, this text underlines that an improved use of other methods as such described here compared to traditional ones has to be performed to better understand the complexity challenging epidemiologists every day. This is particularly true in the field of infectious diseases for which major public health challenges will have to be addressed in the coming decades. PMID:24035791

Hanf, Matthieu; Guégan, Jean-François; Ahmed, Ismail; Nacher, Mathieu

2014-01-01

309

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

310

Crossing the Line: Towards increasingly fruitful complex systems research for the physics community  

E-print Network

This article addresses broad trends in interdisciplinary research in physics where interactions with colleagues in fields such as computer science, ecology, or economics can often be derailed by unintentional clashes of methodologies and perspectives on the core science. Key causes of such breakdowns in interdisciplinary work are detailed and solutions offered.

Reginald D. Smith

2009-12-11

311

The Broad Foundations, 2006  

ERIC Educational Resources Information Center

The mission of the Broad Foundations is to transform K-12 urban public education through better governance, management, labor relations and competition; make significant contributions to advance major scientific and medical research; foster public appreciation of contemporary art by increasing access for audiences worldwide; and lead and…

Broad Foundation, 2006

2006-01-01

312

The iron K line complex in NGC1068: implications for X-ray reflection in the nucleus  

NASA Astrophysics Data System (ADS)

We report a new analysis of ASCA data on the iron K line complex in NGC1068. The line complex basically consists of three components, as previously reported. A weak red wing of the 6.4-keV fluorescence iron K line is found. A plausible explanation is Compton scattering in optically thick, cold matter which can be identified with an obscuring torus or cold gas in the host galaxy. We also show that this `Compton shoulder' should be observable with ASCA using a simulated reflection spectrum. In order to explain the two higher energy lines as well as the cold 6.4-keV line, we fit the ASCA data with a composite model of cold and warm reflection. This shows that cold reflection dominates the observed X-ray emission above 4 keV; the estimated scattering fraction from the warm medium is found to be ~ 0.08 per cent, an order of magnitude below the standard value of 1 per cent obtained from previous observations in other wavebands. The two higher energy lines have large equivalent width (~ 3 keV) with respect to the warm-scattered continuum, suggesting that efficient resonant scattering operates. The line energies are systematically lower than those expected from resonant lines for FeXXV and FeXXVI by ~ 100 eV. The redshifts may be due to either the ionized gas of the warm mirror receding at a radial velocity of 4000-5000 km s^-1 or to effects of Compton scattering in a complicated geometry.

Iwasawa, K.; Fabian, A. C.; Matt, G.

1997-08-01

313

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

314

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

315

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

316

Broad spectrum bioactive sunscreens.  

PubMed

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

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

2008-11-01

317

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

PubMed

The palladium(II) bis-chelate complexes of the type [Pd(TSC(1-5))2] (6-10), with their corresponding ligands 4-phenyl-1-(acetone)-thiosemicarbazone, HTSC(1) (1), 4-phenyl-1-(2'-chloro-benzaldehyde)-thiosemicarbazone, HTSC(2) (2), 4-phenyl-1-(3'-hydroxy-benzaldehyde)-thiosemicarbazone, HTSC(3) (3), 4-phenyl-1-(2'-naphthaldehyde)-thiosemicarbazone, HTSC(4) (4), and 4-phenyl-1-(1'-nitro-2'-naphthaldehyde)-thiosemicarbazone, HTSC(5) (5), were synthesized and characterized by elemental analysis and spectroscopic techniques (IR and (1)H- and (13)C-NMR). The molecular structure of HTSC(3), HTSC(4), and [Pd(TSC(1))2] (6) have been determined by single crystal X-ray crystallography. Complex 6 shows a square planar geometry with two deprotonated ligands coordinated to Pd(II) 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(TSC(3))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.). PMID:24391528

Hernández, Wilfredo; Paz, Juan; Carrasco, Fernando; Vaisberg, Abraham; Spodine, Evgenia; Manzur, Jorge; Hennig, Lothar; Sieler, Joachim; Blaurock, Steffen; Beyer, Lothar

2013-01-01

318

Alpha actinin–CapZ, an anchoring complex for thin filaments in Z-line  

Microsoft Academic Search

CapZ is a widely distributed and highly conserved, heterodimeric protein, that nucleates actin polymerization and binds to the barbed ends of actin filaments, preventing the addition or loss of actin monomers. CapZ interaction with actin filaments was shown to be of high affinity and decreased in the presence of PIP2. CapZ was located in nascent Z-lines during skeletal muscle myofibrillogenesis

Iris Papa; Catherine Astier; Olivier Kwiatek; Fabrice Raynaud; Chantal Bonnal; Marie-Christine Lebart; Claude Roustan; Yves Benyamin

1999-01-01

319

Complex variability pattern in NGC4151 I. Sequences on the line-continuum diagram?  

Microsoft Academic Search

Wepresenttherstresultsofan8-yearspectroscopic 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

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

320

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

321

Study of the anticancer properties of tin(IV) carboxylate complexes on a panel of human tumor cell lines.  

PubMed

A group of organotin(IV) complexes were prepared: [SnCy3 (DMNI)] (1), [SnCy3 (BZDO)] (2), [SnCy3 (DMFU)] (3), and [SnPh2 (BZDO)2 ] (4), for which DMNIH=2,6-dimethoxynicotinic acid, BZDOH=1,4-benzodioxane-6-carboxylic acid, and DMFUH=2,5-dimethyl-3-furoic acid. The cytotoxic activities of compounds 1-4 were tested against pancreatic carcinoma (PANC-1), erythroleukemia (K562), and two glioblastoma multiform (U87 and LN-229) human cell lines; they show very high antiproliferative activity, with IC50 values in the 150-700?nM range after incubation for 72?h. Distribution of cellular DNA upon treatment with 1-4 revealed that whereas compounds 1-3 induce apoptosis in most of the cell lines, compound 4 does not affect cell viability in any cell line tested, indicating a possible difference in cytotoxic mechanism. Studies with the daunomycin-resistant K562/R cell line expressing P-glycoprotein (Pgp) showed that compounds 1-4 are not substrates of this protein efflux pump, indicating that these compounds do not induce acquisition of multidrug resistance, which is associated with the overexpression of Pgp. PMID:22170592

Rocamora-Reverte, Lourdes; Carrasco-García, Estefanía; Ceballos-Torres, Jesús; Prashar, Sanjiv; Kalu?erovi?, Goran N; Ferragut, José A; Gómez-Ruiz, Santiago

2012-02-01

322

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

SciTech Connect

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

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

1982-04-01

323

Trans- and cis-2-phenylindole platinum(II) complexes as cytotoxic agents against human breast adenocarcinoma cell lines  

NASA Astrophysics Data System (ADS)

The synthesis and characterization of the new 2-phenylindole derivative: C8H3N-2-C6H5-3NOMe-5OMe (3c) and the trans- and cis-isomers of [Pt(3c)Cl2(DMSO)] complexes (4c and 5c, respectively) are described. The crystal structures of 4c·CH2Cl2 and 5c confirm: (a) the existence of a Pt-Nindole bond, (b) the relative arrangement of the Cl- ligands [trans- (in 4c) or cis- (in 5c)] and (c) the anti-(E) configuration of the oxime. The cytotoxic assessment of C8H3N-2-(C6H4-4?R1)-3NOMe-5R2 [with R1 = R2 = H (3a); R1 = Cl, R2 = H (3b) and R1 = H, R2 = OMe (3c)] and the geometrical isomers of [Pt(L)Cl2(DMSO)] with L = 3a-3c [trans- (4a-4c) and cis- (5a-5c), respectively] against human breast adenocarcinoma cell lines (MDA-MB231 and MCF-7) is also reported and reveals that all the platinum(II) complexes (except 4a) are more cytotoxic than cisplatin in front of the MCF7 cell line. Electrophoretic DNA migration studies of the synthesized compounds in the absence and in the presence of topoisomerase-I have been performed, in order to get further insights into their mechanism of action.

Tomé, Maria; López, Concepción; González, Asensio; Ozay, Bahadir; Quirante, Josefina; Font-Bardía, Mercè; Calvet, Teresa; Calvis, Carme; Messeguer, Ramon; Baldomá, Laura; Badía, Josefa

2013-09-01

324

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 F(2) 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

325

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

SciTech Connect

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

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

2011-10-10

326

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

PubMed

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

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

2010-06-01

327

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

328

Complex Actions of Thyroid Hormone Receptor Antagonist NH-3 on Gene Promoters in Different Cell Lines  

PubMed Central

It is desirable to obtain new antagonists for thyroid hormone (TRs) and other nuclear receptors (NRs). We previously used X-ray structural models of TR ligand binding domains (LBDs) to design compounds, such as NH-3, that impair coactivator binding to activation function 2 (AF-2) and block thyroid hormone (triiodothyronine, T3) actions. However, TRs bind DNA and are transcriptionally active without ligand. Thus, NH-3 could modulate TR activity via effects on other coregulator interaction surfaces, such as activation function (AF-1) and corepressor binding sites. Here, we find that NH-3 blocks TR-LBD interactions with coactivators and corepressors and also inhibits activities of AF-1 and AF-2 in transfections. While NH-3 lacks detectable agonist activity at T3-activated genes in GC pituitary cells it nevertheless activates spot 14 (S14) in HTC liver cells with the latter effect accompanied by enhanced histone H4 acetylation and coactivator recruitment at the S14 promoter. Surprisingly, T3 promotes corepressor recruitment to target promoters. NH-3 effects vary; we observe transient recruitment of N-CoR to S14 in GC cells and dismissal and rebinding of N-CoR to the same promoter in HTC cells. We propose that NH-3 will generally behave as an antagonist by blocking AF-1 and AF-2 but that complex effects on coregulator recruitment may result in partial/mixed agonist effects that are independent of blockade of T3 binding in some contexts. These properties could ultimately be utilized in drug design and development of new selective TR modulators. PMID:18930112

Shah, Vanya; Nguyen, Phuong; Nguyen, Ngoc-Ha; Togashi, Marie; Scanlan, Thomas S.; Baxter, John D.; Webb, Paul

2014-01-01

329

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

PubMed Central

Swept-source optical coherence tomography (SSOCT) provides a substantial sensitivity advantage over its time-domain counterpart, but suffers from a reduced imaging depth range due to sensitivity falloff and complex conjugate ambiguity. Heterodyne complex conjugate-resolved SSOCT (HCCR-SSOCT) has been previously demonstrated as a technique to completely resolve the complex conjugate ambiguity, effectively doubling the falloff limited imaging depth, without the reduction in imaging speed associated with other CCR techniques. However, previous implementations of this technique have employed expensive and lossy optical modulators to provide the required differential phase modulation. In this paper, we demonstrate the use of a dispersive optical delay line (D-ODL) as the reference arm of an OCT system to realize HCCR-SSOCT. This technique maintains the existing advantages of HCCR-SSOCT in that it completely resolves the complex conjugate artifact and does not reduce imaging speed, while conferring the additional advantages of being low cost, maintaining system sensitivity and resolution, not requiring any additional signal processing, and working at all wavelengths and imaging speeds. The D-ODL also allows for hardware correction of unbalanced dispersion in the reference and sample arm, adding further flexibility to system design. We demonstrate the technique using an SSOCT system operating at 100kHz with a central wavelength of 1040nm. Falloff measurements performed using a standard OCT configuration and the proposed D-ODL demonstrate a doubling of the effective imaging range with no sensitivity or resolution penalty. Feasibility of the technique for in vivo imaging was demonstrated by imaging the ocular anterior segments of healthy human volunteers. PMID:21559133

Dhalla, Al-Hafeez; Izatt, Joseph A.

2011-01-01

330

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

331

Withaferin A modulates the Spindle assembly checkpoint by degradation of Mad2-Cdc20 complex in colorectal cancer cell lines.  

PubMed

Withania somnifera L. Dunal (Ashwagandha) is used over centuries in the ayurvedic medicines in India. Withaferin A, a withanolide, is the major compound present in leaf extract of the plant which shows anticancer activity against leukemia, breast cancer and colorectal cancer. It arrests the ovarian cancer cells in the G2/M phase in dose dependent manner. In the current study we show the effect of Withaferin A on cell cycle regulation of colorectal cancer cell lines HCT116 and SW480 and its effect on cell fate. Treatment of these cells with this compound leads to apoptosis in a dose dependent manner. It causes the G2/M arrest in both the cell lines. We show that Withaferin A (WA) causes mitotic delay by blocking Spindle assembly checkpoint (SAC) function. Apoptosis induced by Withaferin A is associated with proteasomal degradation of Mad2 and Cdc20, an important constituent of the Spindle Checkpoint Complex. Further overexpression of Mad2 partially rescues the deleterious effect of WA by restoring proper anaphase initiation and keeping more number of cells viable. We hypothesize that Withaferin A kills cancer cells by delaying the mitotic exit followed by inducing chromosome instability. PMID:24995417

Das, Tania; Roy, Kumar Singha; Chakrabarti, Tulika; Mukhopadhyay, Sibabrata; Roychoudhury, Susanta

2014-09-01

332

Automated, on-line two-dimensional nano liquid chromatography tandem mass spectrometry for rapid analysis of complex protein digests.  

PubMed

Evaluation of cellular processes and their changes at the level of protein expression and post-translational modifications may allow identification of novel proteins and the mechanisms involved in pathogenic processes. However, the number of proteins and, after tryptic digestion, of peptides from a single cell can be tremendously high. Separation and analysis of such complex peptide mixtures can be performed using multidimensional separation techniques such as two-dimensional gel electrophoresis or two-dimensional-high-performance liquid chromatography (2-D-HPLC). The aim of this work was to establish a fully automated on-line 2-D-HPLC separation method with column switching for the separation of complex tryptic digests. A model mixture of five proteins as well as a nuclear matrix protein sample were digested with trypsin and separated using a strong cation exchange (SCX) column in the first dimension and nano reversed phase in the second dimension. Separated peptides were detected using an ion trap mass spectrometer. The advantages of this new fully automated method are rapid sample loading, the possibility of injecting large volumes and no introduction of salt into the mass spectrometer. Furthermore, column switching allows the independent control and optimization of the two dimensions independently. PMID:15352229

Mitulovi?, Goran; Stingl, Christoph; Smoluch, Marek; Swart, Remco; Chervet, Jean-Pierre; Steinmacher, Ines; Gerner, Christopher; Mechtler, Karl

2004-09-01

333

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

334

On-line speciation analysis of inorganic arsenic in complex environmental aqueous samples by pervaporation sequential injection analysis.  

PubMed

A proof of concept of a novel pervaporation sequential injection (PSI) analysis method for automatic non-chromatographic speciation analysis of inorganic arsenic in complex aqueous samples is presented. The method is based on hydride generation of arsine followed by its on-line pervaporation-based membrane separation and CCD spectrophotometric detection. The concentrations of arsenite (As(III)) and arsenate (As(V)) are determined sequentially in a single sample zone. The leading section of the sample zone merges with a citric acid/citrate buffer solution (pH 4.5) for the selective reduction of As(III) to arsine while the trailing section of the sample zone merges with hydrochloric acid solution to allow the reduction of both As(III) and As(V) to arsine at pH lower than 1. Virtually identical analytical sensitivity is obtained for both As(III) and As(V) at this high acidity. The flow analyzer also accommodates in-line pH detector for monitoring of the acidity throughout the sample zone prior to hydride generation. Under optimal conditions the proposed PSI method is characterized by a limit of detection, linear calibration range and repeatability for As(III) of 22 ?g L(-1) (3sblank level criterion), 50-1000 ?g L(-1) and 3.0% at the 500 ?g L(-1) level and for As(V) of 51 ?g L(-1), 100-2000 ?g L(-1) and 2.6% at the 500 ?g L(-1) level, respectively. The method was validated with mixed As(III)/As(V) standard aqueous solutions and successfully applied to the determination of As(III) and As(V) in river water samples with elevated content of dissolved organic carbon and suspended particulate matter with no prior sample pretreatment. Excellent relative recoveries ranging from 98% to 104% were obtained for both As(III) and As(V). PMID:24209302

Boonjob, Warunya; Miró, Manuel; Kolev, Spas D

2013-12-15

335

Broad-Spectrum Antiviral Therapeutics  

E-print Network

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 ...

Rider, Todd H.

336

Power-line-induced ac potential on natural-gas pipelines for complex rights-of-way configurations. Volume 1. Engineering analysis. Final report  

Microsoft Academic Search

While many benefits accrue from the sharing of corridors for overhead electric-power-transmission lines and buried natural-gas-transmission pipelines, the coupling of electromagnetic energy onto the natural gas transmission pipelines is an undesired consequence of this joint usage. Many common corridors include multiple power lines and pipelines with complexities such as bonds or crossovers between the pipelines and terminating pipelines or insulators.

Frazier

1983-01-01

337

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

PubMed Central

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

338

BeppoSAX broad-band spectra of Seyfert 2 galaxies  

NASA Astrophysics Data System (ADS)

The broad-band 0.1-200keV spectra of a selected sample of Seyfert 2 galaxies have been measured within the BeppoSAX Core Programme. Here we present the first results obtained for 3 objects, NGC172, MKN 3 and NGC 7674. The broad band BeppoSAX data illustrate the high spectral complexity often found in Seyfert 2 galaxies predicted by unified models: NGC 7172 is found to be a Compton-thin source in which the primary emission is seen through absorbing material; MKN 3 is a border line object where the emission is partly seen directly and partly reprocessed by the absorbing material; NGC 7674 is an example of a Compton-thick source where the primary emission is hidden and only reprocessed radiation is observed.

Malaguti, G.; Bassani, L.; Cappi, M.; Comastri, A.; Costa, E.; Dadina, M.; dal Fiume, D.; Di Cocco, G.; Fabian, A. C.; Frontera, F.; Ghisellini, G.; Grandi, P.; Guainazzi, M.; Haardt, F.; Maccacaro, T.; Maiolino, R.; Matsuoka, M.; Matt, G.; Otani, C.; Palumbo, G. G. C.; Piro, L.; Santangelo, A.; Trifoglio, M.; Zhang, N.

1999-01-01

339

Dermatitis and systemic mycosis in lined seahorses Hippocampus erectus associated with a marine-adapted Fusarium solani species complex pathogen.  

PubMed

During a 4 mo epizootic, 100% of 152 lined seahorses Hippocampus erectus in 3 separate groups died while in quarantine following shipment to a public aquarium. Twelve animals with skin depigmentation and ulceration were received by the Aquatic Pathology Service, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA, for diagnostic evaluation. Microscopically, lesions in 11 seahorses included multifocal epithelial necrosis and ulceration associated with 2 to 7 µm diameter, branching, septate fungal hyphae, typically accompanied by deeper infiltration into underlying skeletal muscle. Angioinvasion, with vascular thrombosis and tissue infarction, was a prominent feature in multiple animals. Fungal invasion of one or more internal organs was observed in 4 animals. Hyphae appeared to course freely through tissues and elicited little or no inflammatory response. Fusariosis has been reported sporadically in fish and other aquatic organisms, but identification has often been limited to the genus level based solely on morphologic features. Morphologic characteristics of the fungus isolated from this case were consistent with the Fusarium solani species complex (FSSC), which includes over 50 members that can only be identified definitively using DNA sequence data. A 3-locus typing scheme identified the isolate as a distinct species/haplotype, designated FSSC 12-a, belonging to a specific lineage that appears adapted to aquatic environments and disease in marine animals. Empirical treatment with itraconazole failed to stop mortalities, and subsequent in vitro antifungal susceptibility data explained a lack of clinical efficacy for this agent. Effective treatment in human medicine has similarly been limited by poor susceptibility to several classes of antifungal compounds. PMID:23047188

Salter, Caroline E; O'Donnell, Kerry; Sutton, Deanna A; Marancik, David P; Knowles, Susan; Clauss, Tonya M; Berliner, Aimee L; Camus, Alvin C

2012-10-10

340

Copernicus studies of interstellar material in the Perseus II complex. III - The line of sight to Zeta Persei  

NASA Technical Reports Server (NTRS)

Ultraviolet spectrophotometric data obtained with Copernicus are used to analyze the distribution, composition, density, temperature, and kinematics of the interstellar material along the line of sight to Zeta Persei. The far-UV extinction curve for the star is evaluated along with the kinematics of the interstellar gas, observations of atomic and molecular hydrogen, curves of growth for neutral and ionized species, atomic abundances and depletions, ionization equilibria, and observations of CO and OH lines. The results show that there are apparently three clouds along the line of sight to Zeta Persei: a main cloud at approximately +13 km/s which contains most of the material and forms all the neutral and molecular lines as well as most of the ionic lines, a second component at +22 km/s which must contribute to the strong UV lines of most ions, and a third component at roughly +2 km/s which gives rise to a strong Si III line at 1206 A. It is also found that the UV extinction curve has a somewhat steep far-UV rise, indicating the presence of a substantial number of small grains, and that about 30% of the hydrogen nuclei over the entire line of sight are in molecular form.

Snow, T. P., Jr.

1977-01-01

341

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

342

Mycobacterium riyadhense sp. nov., a non-tuberculous species identified as Mycobacterium tuberculosis complex by a commercial line-probe assay  

Microsoft Academic Search

A non-chromogenic, slowly growing Mycobacterium strain was isolated from a maxillary sinus lavage from a symptomatic patient in Riyadh, Saudi Arabia. It was initially identified as a member of the Mycobacterium tuberculosis complex by a commercial line-probe assay. Its 16S rRNA, hsp65 and rpoB gene and 16S-23S internal transcribed spacer sequences were unique; phylogenetic analysis based on the 16S rRNA

J. van Ingen; S. A. M. Al-Hajoj; M. J. Boeree; F. Al-Rabiah; M. Enaimi; R. de Zwaan; E. Tortoli; R. Dekhuijzen; D. van Soolingen

2009-01-01

343

Disentangling the complexity of infectious diseases: time is ripe to improve the first-line statistical toolbox for epidemiologists  

E-print Network

1 Disentangling the complexity of infectious diseases: time is ripe to improve the first on Biodiversity, Climate Change and Infectious Diseases, Centre IRD de Montpellier, BP 64501, F- 34394 Montpellier of infectious diseases are caused by complex interactions between the environment, the host(s) and the agent

Boyer, Edmond

344

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

345

Broad Street Books The Wesleyan University Bookstore  

E-print Network

Broad Street Books The Wesleyan University Bookstore 45 Broad Street Middletown, CT 06457 April 1 and class rings. All these items can be purchased through Broad Street Books, your local university store your regalia at the bookstore, we will be glad to have it shipped to you. Contact Broad Street Books

Royer, Dana

346

The Design of Efficient Broad-Band Piezoelectric Transducers  

Microsoft Academic Search

Absrruct-A design method for acoustic thin disk transducers with high efficiency, broad bandwidth, and good impulse response is presented. This method is based on the use of quarter-wave matching layers between the piezoelectric material and the acoustic load. As is made evident using the transmission line model of Krimholtz, Leedom, and Matthaei, the finite thickness of the piezoelectric material must

C. S. Desilets; J. D. Fraser; G. S. Kino

1978-01-01

347

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. PMID:21818340

Rider, Todd H.; Zook, Christina E.; Boettcher, Tara L.; Wick, Scott T.; Pancoast, Jennifer S.; Zusman, Benjamin D.

2011-01-01

348

Characterization of the Androgen-sensitive MDA-kb2 Cell Line for Assessing Complex Environmental Mixtures  

EPA Science Inventory

Complex mixtures of synthetic and natural androgens and estrogens, and many other non-steroidal components are commonly released to the aquatic environment from anthropogenic sources. It is important to understand the potential interactive (i.e., additive, synergistic, antagonist...

349

Bay0 × Shahdara recombinant inbred line population: a powerful tool for the genetic dissection of complex traits in Arabidopsis  

Microsoft Academic Search

Natural genetic variation in Arabidopsis is considerable, but has not yet been used extensively as a source of variants to identify new genes of interest. From the cross between two genetically distant ecotypes, Bay-0 and Shahdara, we generated a Recombinant Inbred Line (RIL) population dedicated to Quantitative Trait Locus (QTL) mapping. A set of 38 physically anchored microsatellite markers was

O. Loudet; S. Chaillou; C. Camilleri; D. Bouchez; F. Daniel-Vedele

2002-01-01

350

The Molecular Counterpart of the Galactic Center Arched Filament HII Complex: OVRO Observations of the CS(2-1) Line  

E-print Network

The Owens Valley Radio Observatory (OVRO) millimeter array was used to make observations of the CS(2-1) line (at 97.981 GHz) arising from the G0.07+0.04 region of the ``-30 km/s'' molecular cloud near the Galactic center with a spatial resolution of ~8". The ionized edges of this cloud forms the Arched Filament HII regions which are ionized by the adjacent Arches stellar cluster. The OVRO data were combined with single-dish data obtained at the 30-m IRAM telescope by Serabyn & Guesten (1987). A comparison of this CS(2-1) data and the H92alpha recombination line data of Lang, Goss & Morris (2001) reveals that the ionized and molecular gas are physically related, but that their velocities in this region differ by up to 35 km/s. This difference in velocity can be understood if the gas that gave rise to the G0.07+0.04 HII region has been fully ionized. An overall comparison of the molecular and ionized gas across the entire -30 km/s cloud based on the single dish CS(2-1) data and the H92alpha line data illustrates that such differences in velocity between the ionized and molecular gas are common and that the geometrical arrangement of these components is complicated. Much of the ionized gas resides on the near side (to the observer) of the molecular cloud; however, in several regions, some molecular material must lie in front of the HII region. The Arches stellar cluster therefore appears to be located in the midst of the molecular clouds such that some of the near-side cloud surfaces along our line of sight have not been exposed to the ionizing radiation.

Cornelia C. Lang; W. M. Goss; Mark Morris

2002-08-16

351

Intravenous adenosine as first-line prehospital management of narrow-complex tachycardias by EMS personnel without direct physician control  

Microsoft Academic Search

This study was conducted to evaluate the safety and efficacy of intravenous adenosine therapy for prehospital treatment of narrow-complex tachycardias with a presumptive field diagnosis of paroxysmal supraventricular tachycardia (PSVT) by paramedics without direct physician control. A ten-month prospective case series was designed in an urban EMS system that has paramedics operating under standing orders before physician radio contact. All

Richard Furlong; Robert T Gerhardt; Pamela Farber; Kathleen Schrank; Regina Willig; Juan Pittaluga

1995-01-01

352

Characterization of the Androgen-sensitive MDA-kb2 Cell Line for Assessing Complex Environmental Mixtures, Presentation  

EPA Science Inventory

Synthetic and natural steroidal androgens and estrogens and many other non-steroidal endocrine-active compounds commonly occur as complex mixtures in aquatic environments. It is important to understand the potential interactive effects of these mixtures to properly assess their r...

353

The Molecular Counterpart of the Galactic Center Arched Filament HII Complex OVRO Observations of the CS(2-1) Line  

E-print Network

The Owens Valley Radio Observatory (OVRO) millimeter array was used to make observations of the CS(2-1) line (at 97.981 GHz) arising from the G0.07+0.04 region of the ``-30 km/s'' molecular cloud near the Galactic center with a spatial resolution of ~8". The ionized edges of this cloud forms the Arched Filament HII regions which are ionized by the adjacent Arches stellar cluster. The OVRO data were combined with single-dish data obtained at the 30-m IRAM telescope by Serabyn & Guesten (1987). A comparison of this CS(2-1) data and the H92alpha recombination line data of Lang, Goss & Morris (2001) reveals that the ionized and molecular gas are physically related, but that their velocities in this region differ by up to 35 km/s. This difference in velocity can be understood if the gas that gave rise to the G0.07+0.04 HII region has been fully ionized. An overall comparison of the molecular and ionized gas across the entire -30 km/s cloud based on the single dish CS(2-1) data and the H92alpha line data il...

Lang, C C; Morris, M; Lang, Cornelia C.; Morris, Mark

2002-01-01

354

On the importance of satellite lines to the He-like alpha complex and the G ration for calcium, iron, and nickel  

SciTech Connect

New, more detailed calculations of the emission spectra of the He-like Ko complex of calcium, iron and nickel have been carried out using data from both distorted-wave and R-matrix calculations. The value of the GD ratio (a corrected version of the G ratio that accounts for the effect of unresolved satellite lines) is significantly enhanced at temperatures below the temperature of He-like maximum abundance. Furthermore it is shown that satellite lines are important contributors to the G D ratio at temperatures well above the temperature of maximum abundance. These new calculations demonstrate that satellite lines need to be included in models of He-like Ko spectra even at relatively high temperatures. The excellent agreement between spectra and line ratios calculated from R-matrix and distorted-wave data also confirms the validity of models based on distorted-wave data for highly charged systems, provided the effect of resonances are taken into account as independent processes.

Oelgoetz, Justin R [Los Alamos National Laboratory; Fontes, Christopher J [Los Alamos National Laboratory; Zhang, Hong L [Los Alamos National Laboratory; Nahar, Sultana N [OHIO STATE UNIV; Pradhan, Anil K [OHIO STATE UNIV

2008-01-01

355

DDX3X, the X homologue of AZFa gene DDX3Y, expresses a complex pattern of transcript variants only in the male germ line.  

PubMed

DDX3X, the functional X homologue of the major AZFa gene, DDX3Y, belongs to the highly conserved PL10-subfamily of DEAD-box RNA helicase genes which are functionally conserved from yeast to man. They are mainly involved in cell cycle control and translation initiation control of gene transcripts with long 5'UTR extensions containing complex secondary structures. Interestingly, in humans both gene copies were found to be expressed at different phases of human spermatogenesis. Whereas DDX3Y transcripts are translated only in premeiotic male germ cells, the DDX3X protein is expressed only in postmeiotic spermatids. In this study, we found that the major class of DDX3X transcripts in human testis become activated first after meiosis and at a specific core promoter not active in somatic tissues and not present upstream of the DDX3Y homologue. Two alternative 5'UTR transcript lengths are subsequently produced by an additional testis-specific 5'UTR splicing event. Both transcripts are mainly processed for polyadenylation in their proximal 3'UTR. A minor transcript class starting at the same male germ line-specific core promoter produces primary transcripts with an extremely long 3'UTR (?17 kb), which is subsequently spliced at distinct sites resulting in six short 3'UTR splice variants (I-VI). Comparative analyses of the DDX3X transcripts in mouse and primates revealed that this complex pattern of male germ line-specific transcript variants first evolved in primates. Our data thus suggest complex translational control mechanism(s) for the human DDX3X gene locus functioning only in the male germ line and resulting in expression of its protein only in the postmeiotic spermatids. PMID:25208899

Rauschendorf, Marc-Alexander; Zimmer, Jutta; Ohnmacht, Caroline; Vogt, Peter H

2014-12-01

356

Developing the Broad Process Excellence Program  

E-print Network

This thesis is based on the author's experience as an intern at the Broad Institute of MIT and Harvard. The Broad Institute has been working on applying and implementing traditional manufacturing process improvement tools ...

Datta, Subhrangshu, 1975-

2007-01-01

357

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

358

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

359

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

360

A method for synthesizing pattern with broad null  

NASA Astrophysics Data System (ADS)

Based on the Gram-Schmidt orthogonalization method utilized for pattern synthesis of linear array without constraints, side lobe levels constraints in certain angular region is proposed to implement pattern synthesis with broad nulls. The advantage of the simplified computation resulted from steering vector orthogonalization in unconstrained orthogonal approach is maintained, and the uniform or non-uniform linear array pattern synthesis can be realized by this method. The computational complexity of this method is smaller than iterative algorithm method's. The experimental results show that the side lobe levels constrained orthogonal approach can fulfill linear array broad null pattern synthesis with less computational efforts.

Zeng, Zhuanwu; Zhang, Liqiang; Huang, Longyang; Zhang, Guangfu; Li, Mengxing

2013-03-01

361

Effect of Invariant Chain on Major Histocompatibility Complex Class I Molecule Expression and Stability on Human Breast Tumor Cell Lines  

PubMed Central

Invariant chain (Ii) binds to the human leukocyte antigen (HLA) class II molecule and assists it in the process of peptide acquisition. In addition, Ii binds to the HLA class I molecule, although there has been little study of its effects on the HLA class I molecule. In addition to its normal expression on antigen-presenting cells, Ii expression is up regulated in a variety of tumors. By flow cytometric analysis, we found that expression of Ii resulted in an increase in the number of cell surface HLA class I molecules and in the proportion of unstable HLA class I molecules at the surface of breast tumor cell lines. These data suggest that the expression of Ii by tumor cells may quantitatively and qualitatively alter the presentation of antigens on those cells. PMID:18828016

Lin, Xuede; Wang, Xiaojian; Capek, Haley L.; Simone, Laura C.; Tuli, Amit; Morris, Chantey R.; Reber, Adrian J.; Solheim, Joyce C.

2008-01-01

362

Jupiter's Temperatures--Broad Latitude  

NASA Technical Reports Server (NTRS)

This is one of the highest resolution images ever recorded of Jupiter's temperature field. It was obtained by NASA's Galileo mission, with its Photopolarimeter-Radiometer (PPR) experiment, during the seventh of its 10 orbits around Jupiter to date. This map, shown in the left panel, indicates the forces powering Jovian winds, and differentiates between areas of strongest upwelling and downwelling winds in the upper part of the atmosphere. A Hubble Space Telescope Planetary Camera color composite of this same region, taken within 10 hours of the PPR map, is shown in the right panel for the same region, as a reference to the visual clouds. An outline of the region mapped by the PPR is also shown.

This atmospheric observation covered a broad latitude region, and it shows that the visually dark regions generally have warmer temperatures than the visually light ones, indicating that they are regions of downwelling, dry air which clear out cloud condensate particles. The 'little red spot' at the northernmost part of this image is colder than its surroundings, consistent with it being a region of upwelling and cooling gas. The smaller spots to its southeast (lower right) and other lighter spots in the HST image are all colder than their surroundings, consistent with regions of upwelling and cooling gas. The northern half of the brightest band in the map is brighter than the southern half, and it reveals some detailed structure, down to the 1900- kilometer (1200-mile) resolution of the PPR, which is not always readily correlated with variations of the visual cloud field.

One surprise of this temperature map involved temperatures near the dark blue-gray feature in the map, an area like the one into which the Probe descended. While large regions of downwelling wind heat the local area elsewhere in Jupiter, this region of vigorous downwelling appears close to being thermally neutral. The drying, downwelling winds may be deeper in the atmosphere than sensed by the PPR, or this region may have enough downwelling motions so that additional downwelling has little effect on energy and temperature. Either scenario indicates these generally clear and dry regions are fundamentally different from most of Jupiter's downwelling regions.

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

1997-01-01

363

Complex expression pattern of the Barth syndrome gene product tafazzin in human cell lines and murine tissues.  

PubMed

Tafazzins, a group of proteins that are defective in patients with Barth syndrome, are produced by alternate splicing of the gene G4.5 or TAZ. RT-PCR and transcription-coupled in vitro translation analysis were undertaken to determine the expression of alternatively spliced TAZ mRNA in mouse tissues and human cell lines. Only two tafazzin transcripts, both lacking exon 5, were expressed in murine tissues, whereas four tafazzin transcripts, all lacking exon 5, were observed in human umbilical vein vascular endothelial cells and U937 human monoblasts indicating a species-specific difference in the expression of TAZ mRNAs in mouse and humans. Only TAZ lacking exon 5 was expressed in murine heart. Differentiation of U937 human monoblasts into macrophages did not alter expression of the tafazzin transcripts indicating that TAZ expression is independent of monocyte differentiation. Cloning and in vitro expression of both murine and human tafazzin cDNA revealed two prominent protein bands that corresponded to the expected sizes of alternative translation. A novel fifth motif, identified as critical for the glycerolphosphate acyltransferase family, was observed in human tafazzin. The presence of a mutation in this region in Barth syndrome patients indicates that this motif is essential for tafazzin function. PMID:15499385

Lu, Biao; Kelher, Marguerite R; Lee, Douglas P; Lewin, Tal M; Coleman, Rosalind A; Choy, Patrick C; Hatch, Grant M

2004-10-01

364

33 CFR 110.27 - Lynn Harbor in Broad Sound, Mass.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Lynn Harbor in Broad Sound, Mass. 110.27 Section 110.27 Navigation and Navigable Waters...Special Anchorage Areas § 110.27 Lynn Harbor in Broad Sound, Mass. North of a line bearing 244° from the tower of...

2010-07-01

365

33 CFR 334.475 - Brickyard Creek and tributaries and the Broad River at Beaufort, SC.  

Code of Federal Regulations, 2010 CFR

...longitude 80.69960°. (9) (Laurel Bay Military Family Housing Area, Broad River...beginning on the western shoreline of Laurel Bay Military Family Housing Area boundary line...the Commander, MCAS, Beaufort, South Carolina. (4) Unauthorized personnel,...

2010-07-01

366

Pictor A: A new double-peaked emission-line quasar  

Microsoft Academic Search

We obtained a new spectrum for the radio galaxy Pictor A in 1993 December. Comparison with previous data obtained in 1983 and 1987 shows that the broad component of the Balmer lines has increased considerably in strength and complexity. The Balmer lines now show a boxy, double-peaked profile with Full Width at Zero Intensity (FWZI) approximately 24,000 km\\/s. Although the

J. W. Sulentic; P. Marziani; T. Zwitter; M. Calvani

1995-01-01

367

Mycobacterium riyadhense sp. nov., a non-tuberculous species identified as Mycobacterium tuberculosis complex by a commercial line-probe assay.  

PubMed

A non-chromogenic, slowly growing Mycobacterium strain was isolated from a maxillary sinus lavage from a symptomatic patient in Riyadh, Saudi Arabia. It was initially identified as a member of the Mycobacterium tuberculosis complex by a commercial line-probe assay. Its 16S rRNA, hsp65 and rpoB gene and 16S-23S internal transcribed spacer sequences were unique; phylogenetic analysis based on the 16S rRNA gene sequence groups this organism close to Mycobacterium szulgai and Mycobacterium malmoense. Its unique biochemical properties and mycolic acid profile support separate species status. We propose the name Mycobacterium riyadhense sp. nov. to accommodate this strain. The type strain is NLA000201958(T) (=CIP 109808(T) =DSM 45176(T)). PMID:19406791

van Ingen, Jakko; Al-Hajoj, Sahal A M; Boeree, Martin; Al-Rabiah, Fahad; Enaimi, Mimount; de Zwaan, Rina; Tortoli, Enrico; Dekhuijzen, Richard; van Soolingen, Dick

2009-05-01

368

Petrology of the Guenfalabo ring-complex: An example of a complete series along the Cameroon Volcanic Line (CVL), Cameroon  

NASA Astrophysics Data System (ADS)

In the Guenfalabo ring-complex (GRC), two non-comagmatic rock suites have been identified as a result of two volcanic episodes: Suite 1 (68.8 ± 1.7 Ma by K/Ar on trachyte) of peralkaline trachytes and pantellerites cogenetic with alkaline syenites, granites and rhyolitic flows and tuffs; Suite 2 (62 ± 2 Ma by K/Ar on basalt), a bimodal and complete series of alkali olivine basalts and associated microgabbro dykes, diorites, syenites and granites, cross-cutting the former. Kaersutite in the trachytes of Suite 1 has mantle-derived signatures: TiO2 > 4%, MgO < 15%, FeO > 8%, Ti = 0.63 c.p.f.u. and Al = 2, characteristic of kaersutites of HP and HT origin: 13-23 kbar, 1100-1220 °C. The trachytes are probably products of FC of a basaltic parent that did not attain higher crustal levels. The Suite 1 rocks are enriched in Rb, K, Zr, Nb, LREE, alkalis, and (Ce/Yb)N = 7-15 probably due to some effect of metasomatism during the m