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1

Hydrogen Balmer Emission Lines and the Complex Broad Line Region Structure  

E-print Network

In this work we investigate the properties of the broad emission line components in the Balmer series of a sample of Type 1 Active Galactic Nuclei (AGN). Using the Boltzmann Plot method as a diagnostic tool for physical conditions in the plasma, we detect a relationship among the kinematical and thermo-dynamical properties of these objects. In order to further clarify the influence of the central engines on the surrounding material, we look for signatures of structure in the broad line emitting regions, that could affect the optical domain of the observed spectra. Using a combination of line profile analysis and kinematical modeling of the emitting plasma, we study how the emission line broadening functions are influenced by different structural configurations. The observed profiles are consistent with flattened structures seen at quite low inclinations, typically smaller than 20 degrees. Since this result is in good agreement with some independent observations at radio frequencies, we apply a new formalism t...

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

2009-01-01

2

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

3

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.

4

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

5

What is the Broad Line Region?  

E-print Network

What is the Broad Line Region (BLR) made of? What determines its location? Why is it sometimes missing? What controls its properties? Some recent results and new approaches which may shed light on these issues are briefly described.

Ari Laor

2003-12-16

6

Fermi/LAT broad emission line blazars  

NASA Astrophysics Data System (ADS)

We study the broad emission line blazars detected in the ?-ray band by the Large Area Telescope onboard the Fermi satellite and with the optical spectrum studied by Shaw et al. The observed broad line strength provides a measure of the ionizing luminosity of the accretion disc, while the ?-luminosity is a proxy for the bolometric non-thermal beamed jet emission. The resulting sample, composed by 217 blazars, is the best suited to study the connection between accretion and jet properties. We compare the broad emission line properties of these blazars with those of radio-quiet and radio-loud quasars present in the Sloan Digital Sky Survey, to asses differences and similarities of the disc luminosity and the virial black hole mass. For most sources, we could derive the black hole mass by reproducing the IR-optical-UV data with a standard accretion disc spectrum, and we compared the black hole masses derived with the two methods. The distributions of the masses estimated in the two ways agree satisfactorily. We then apply a simple, one-zone, leptonic model to all the 217 objects of our sample. The knowledge of the black hole mass and disc luminosity helps to constrain the jet parameters. On average, they are similar to what found by previous studies of smaller samples of sources.

Ghisellini, G.; Tavecchio, F.

2015-04-01

7

Fermi/LAT broad emission line blazars  

E-print Network

We study the broad emission line blazars detected in the gamma-ray band by the Large Area Telescope onboard the Fermi satellite and with the optical spectrum studied by Shaw et al. (2012, 2013). The observed broad line strength provides a measure of the ionizing luminosity of the accretion disk, while the gamma-luminosity is a proxy for the bolometric non-thermal beamed jet emission. The resulting sample, composed by 217 blazars, is the best suited to study the connection between accretion and jet properties. We compare the broad emission line properties of these blazars with those of radio-quiet and radio-loud quasars present in the Sloan Digital Sky Survey, to asses differences and similarities of the disc luminosity and the virial black hole mass. For most sources, we could derive the black hole mass by reproducing the IR-optical-UV data with a standard accretion disc spectrum, and we compared the black hole masses derived with the two methods. The distributions of the masses estimated in the two ways agre...

Ghisellini, G

2015-01-01

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

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

10

Constraining broad-line regions from time lags of broad emission lines relative to radio emission  

NASA Astrophysics Data System (ADS)

In this paper, a new method is proposed to estimate the broad-line region sizes of ultraviolet (UV) lines RuvBLR. It is applied to 3C 273. First, we derive the time lags of radio emission relative to broad emission lines Ly? and C IV by the z-transformed discrete correlation function (ZDCF) method. The broad lines lag the 5-, 8-, 15-, 22- and 37-GHz emission. The measured lags ?uvob are of the order of years. For a given line, ?uvob decreases as the radio frequency increases. This trend results from the radiative cooling of relativistic electrons. Both UV lines have a lag of ?uvob=-2.74+0.06- 0.25 yr relative to the 37-GHz emission. These results are consistent with those derived from the Balmer lines in Paper I. Secondly, we derive the time lags of the lines Ly?, C IV, H?, H? and H? relative to the 37-GHz emission by the flux randomization/random subset selection (FR/RSS) Monte Carlo method. The measured lags are ?ob=-3.40+0.31- 0.05, -3.40+0.41- 0.14, -2.06+0.36- 0.92, -3.40+1.15- 0.20 and -3.56+0.35- 0.18 yr for the lines Ly?, C IV, H?, H? and H?, respectively. These estimated lags are consistent with those derived by the ZDCF method within the uncertainties. Based on the new method, we derive RuvBLR= 2.54+0.71- 0.35 to 4.01+0.90- 1.16 and 2.54+0.80- 0.43 to 4.01+0.98- 1.24 light-years for the Ly? and C IV lines, respectively. Considering the uncertainties, these estimated sizes are consistent with those obtained in the classical reverberation mapping for the UV and the Balmer lines. This indicates that their emitting regions are not separated so large as in the classical mapping of the UV and optical lines. These results seem to depart from the stratified ionization structures obtained in the classical mapping.

Liu, H. T.; Bai, J. M.; Wang, J. M.; Li, S. K.

2011-11-01

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

A Balmer-line Broad Absorption Line Quasar  

E-print Network

I report the discovery of blueshifted broad absorption line (BAL) troughs in at least six transitions of the Balmer series of hydrogen (Hbeta to H9) and in CaII, MgII and excited FeII in the quasar SDSS J125942.80+121312.6. This is only the fourth active galactic nucleus known to exhibit Balmer absorption, all four in conjunction with low-ionization BAL systems containing excited Fe II. The substantial population in the n=2 shell of H I in this quasar's absorber likely arises from Ly-alpha trapping. In an absorber sufficiently optically thick to show Balmer absorption, soft X-rays from the quasar penetrate to large \\tau_Ly\\alpha and ionize H I. Recombination then creates Ly-alpha photons that increase the n=2 population by a factor \\tau_Ly\\alpha since they require about \\tau_Ly\\alpha scatterings to diffuse out of the absorber. Observing Ly-alpha trapping in a quasar absorber requires a large but Compton-thin column of gas along our line of sight which includes substantial H I but not too much dust. Presumably the rarity of Balmer-line BAL troughs reflects the rarity of such conditions in quasar absorbers.

Patrick B. Hall

2006-11-29

13

AGN Broad Emission Lines from Magneto-Centrifugally Driven Winds  

NASA Astrophysics Data System (ADS)

We study the formation of AGN broad emission lines in the magneto-centrifugally driven wind model of Emmering, Blandford & Shlosman (1992). In contrast to previous work (Bottorff et al. 1997), we use a photoionization code (CLOUDY) to compute the ionization structure and line emissivity in the wind assuming that it consists of a smooth outflow rather than a large number of high density clouds. Similar to the radiatively driven disk-wind model of Murray et al. (1995), large velocity gradients in a magnetically driven wind will cause optically thick lines such as Civ to be strongly anisotropic. This will have a significant impact on the shape of the resulting broad emission lines. We compare emission line profile shapes, reverberation mapping response and broad absorption line shapes for the two models and discuss observational tests for discriminating between them.

Chiang, J.; Murray, N.

1998-05-01

14

Deficiency of Broad Line AGNs in Compact Groups of Galaxies  

E-print Network

Based on a new survey of AGN activity in Compact Groups of Galaxies, we report a remarkable deficiency of Broad Line AGNs as compared to Narrow Line AGNs. The cause of such deficiency could be related to the average low luminosity of AGNs in CGs: $10^{39}$ erg s$^{-1}$. This result may imply lower accretion rates in CG AGNs, making Broad Line Regions (BLR) undetectable, or may indicate a genuine absence of BLRs. Both phenomena are consistent with gas stripping through tidal interaction and dry mergers.

M. A. Martinez; A. del Olmo; R. Coziol; P. Focardi

2008-03-25

15

The profiles of polarized broad H? lines in radio galaxies  

NASA Astrophysics Data System (ADS)

We present spectropolarimetric observations of seven broad-line radio galaxies. We find significantly polarized broad H? emission in four objects including two, Arp 102B and 3C390.3, which have double-peaked line profiles. In these objects the prominent redshifted and blueshifted peaks of the broad H? line have no clear counterparts in polarized flux. This conflicts with theoretical predictions for a relativistic line-emitting disc with an electron scattering atmosphere, one of the leading models advanced to account for the double-peaked lines. The shapes and widths of the polarized line profiles can be explained if, as expected in unified schemes, the scattering occurs near the poles of an obscuring torus. However, the observed polarization position angles favour geometries in which the scattering plane is perpendicular to the radio jet. A configuration in which H? photons emitted by a biconical flow are scattered off the inner wall of the torus has this property, and would also produce a single-peaked scattered line profile. With the exception of 3C227, the sample as a whole conforms to the general trend in powerful radio galaxies for the optical polarization to be aligned with the radio source axis, favouring toroidal rather than polar scattering.

Corbett, Elizabeth A.; Robinson, A.; Axon, D. J.; Young, S.; Hough, J. H.

1998-05-01

16

NEW CONSTRAINTS ON THE QUASAR BROAD EMISSION LINE REGION  

SciTech Connect

We demonstrate a new technique for determining the physical conditions of the broad-line-emitting gas in quasars, using near-infrared hydrogen emission lines. Unlike higher ionization species, hydrogen is an efficient line emitter for a very wide range of photoionization conditions, and the observed line ratios depend strongly on the density and photoionization state of the gas present. A locally optimally emitting cloud model of the broad emission line region was compared to measured emission lines of four nearby (z Almost-Equal-To 0.2) quasars that have optical and NIR spectra of sufficient signal to noise to measure their Paschen lines. The model provides a good fit to three of the objects, and a fair fit to the fourth object, an ultraluminous infrared galaxy. We find that low-incident-ionizing fluxes ({Phi}{sub H} < 10{sup 18} cm{sup -2} s{sup -1}) and high gas densities (n{sub H} > 10{sup 12} cm{sup -3}) are required to reproduce the observed hydrogen emission line ratios. This analysis demonstrates that the use of composite spectra in photoionization modeling is inappropriate; models must be fitted to the individual spectra of quasars.

Ruff, Andrea J.; Floyd, David J. E.; Webster, Rachel L.; Landt, Hermine [School of Physics, University of Melbourne, Parkville, VIC 3010 (Australia); Korista, Kirk T., E-mail: aruff@unimelb.edu.au [Department of Physics, Western Michigan University, Kalamazoo, MI 49008 (United States)

2012-07-20

17

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

18

Line Narrowing of a Broad Area Laser Diode  

NASA Astrophysics Data System (ADS)

An external cavity for a broad area laser diode will be presented which significantly narrows the spectral bandwidth. Broad area laser (BAL) diodes are relatively low cost while achieving high output powers with a compact and efficient design. However, they generally have poor spatial characteristics and a typical linewidth of several nanometers. In order to make BAL diodes useful for such applications as spin-exchange optical pumping, laser spectroscopy, and nonlinear optics, a narrow linewidth is crucial. Previously we reported on a narrowband external cavity laser diode arrayootnotetextB.V. Zhdanov, T. Ehrenreich, and R.J. Knize, Elec. Lett. 43 (4), 221 (2007)., which achieved a linewidth of 11 GHz and an operating power of approximately 10 W at 852 nm, making it very useful for cesium vapor laser pumping. We will present our most recent results of further line narrowing (MHz's) using a high power (30 W) single emitter broad area laser diode.

Sell, Jerry; Miller, Wooddy; Wright, Dallas; Zhdanov, Boris; Knize, Randy

2008-05-01

19

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

20

Broad Absorption Line Quasar catalogues with Supervised Neural Networks  

E-print Network

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.

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

2008-10-24

21

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

22

Broad-line active galactic nuclei rotate faster than narrow-line ones.  

PubMed

The super-massive black holes of 10(6)M(?) to 10(9)M(?) that reside in the nuclei of active galaxies (AGN) are surrounded by a region emitting broad lines, probably associated with an accretion disk. The diameters of the broad-line regions range from a few light-days to more than a hundred light-days, and cannot be resolved spatially. The relative significance of inflow, outflow, rotational or turbulent motions in the broad-line regions as well as their structure (spherical, thin or thick accretion disk) are unknown despite intensive studies over more than thirty years. Here we report a fundamental relation between the observed emission linewidth full-width at half-maximum (FWHM) and the emission line shape FWHM/?(line) in AGN spectra. From this relation we infer that the predominant motion in the broad-line regions is Keplerian rotation in combination with turbulence. The geometry of the inner region varies systematically with the rotation velocity: it is flattest for the fast-rotating broad-line objects, whereas slow-rotating narrow-line AGN have a more spherical structure. Superimposed is the trend that the line-emitting region becomes geometrically thicker towards the centre within individual galaxies. Knowing the rotational velocities, we can derive the central black-hole masses more accurately; they are two to ten times smaller than has been estimated previously. PMID:21331037

Kollatschny, Wolfram; Zetzl, Matthias

2011-02-17

23

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

24

Probing AGN Broad Line Regions With LAT Observations of FSRQs  

SciTech Connect

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

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

2007-10-11

25

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

26

The Broad-lined Type Ic SN 2003jd  

E-print Network

The results of a world-wide coordinated observational campaign on the broad-lined Type Ic SN 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 M_{ej} = 3.0 +/- 1 Mo and a kinetic energy of E_{k}(tot) = 7_{-2}^{+3} 10^{51} erg. 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, due to the similarity of SN 2003jd to the SN 2006aj/XRF 060218 event, we discuss the possible connection of SN 2003jd with a GRB.

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

2007-10-26

27

Spectral Decomposition of Broad-Line AGNs and Host Galaxies  

E-print Network

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.

Daniel E. Vanden Berk; Jiajian Shen; Ching-Wa Yip; Donald P. Schneider; Andrew J. Connolly; Ross E. Burton; Sebastian Jester; Patrick B. Hall; Alex S. Szalay; John Brinkmann

2005-09-13

28

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

29

Broad Radio Recombination Lines from Hypercompact H II Regions  

NASA Astrophysics Data System (ADS)

An extensive study of hypercompact (HC) H II regions was initiated using the VLA to investigate the origin and nature of the broad (FWHM > 40 km s-1) lines detected toward 8 of them. HC H II regions are about ten times smaller and a hundred times denser than ultracompact (UC) H II regions. They show rising continuum spectral indices of ? ˜ +1 (S? ? ? ? ) from short cm to mm wavelengths, sizes ? 0.01 pc, electron densities ? 105 cm-3, and emission measures ? a few times 108 pc cm-6. HC H II regions may represent a new intermediate stage of early massive star evolution, the transition from the rapid accretion phase of massive star formation to the emergence of UC H II regions. The nature of the line broadening in HC H II regions is uncertain. It may be produced by a combination of thermal, turbulent, electron impact broadening, and large scale motions (rotation, expansion, outflow, inflow, disk, etc.). We have obtained high spatial resolution observations of H92? to H53? recombination lines toward several HC H II regions to determine the main broadening contributions to the line profiles. Funding for this research was provided in part by NSF grant AST-0303689 (EBC), CONACyT grant E-36568 and DGAPA-UNAM grant IN118401 (SK), Research Corporation Grant CC4996 and NSF grant AST-0098524 (PH).

Sewilo, M.; Churchwell, E.; Kurtz, S.; Goss, W. M.; Hofner, P.

2004-12-01

30

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

31

Extragalactic jets of broad absorption line (BAL) quasars  

NASA Astrophysics Data System (ADS)

Fast outflows of the ionized plasma, probably lunched in proximity of Supermassive Black Hole, are responsible for blue-shifted Broad Absorption Lines (BALs) in quasar spectrum. Outflows together with powerful jets produced in AGN are important feedback processes. Therefore, understanding physics behind BAL outflows might be a key to comprehend Galaxy Evolution as a whole. Discovery of the existence of radio-loud BAL quasars gave us another opportunity to study the BAL phenomenon, this time on the ground on radio emission. The radio emission is an additional tool to understand the BAL quasars, their orientation and age, by the VLBI imaging (detection of radio jets and their direction, size determination), the radio-loudness parameter distribution and variability study.

Kunert-Bajraszewska, M.; Ceg?owski, M.; Roskowi?ski, C.; Gawro?ski, M.

2015-03-01

32

The Physical Nature of Polar Broad Absorption Line Quasars  

NASA Technical Reports Server (NTRS)

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

Ghost, Kajal; Punsly, Brian

2007-01-01

33

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

34

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

35

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

36

Line Shifts, Broad-line Region Inflow, and the Feeding of Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

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; Goosmann, René W.

2013-05-01

37

Role of echocardiography in differential diagnosis of broad complex tachycardia.  

PubMed Central

It is not always easy to distinguish between supraventricular tachycardia with aberration and ventricular tachycardia by electrocardiographic analysis alone. M mode echocardiography can often help by providing direct or indirect evidence of the relation between atrial and ventricular contraction. Sixteen consecutive patients with spontaneous sustained broad QRS complex tachycardia with heart rates of 120-225 beats/minute were examined. Echocardiographic evidence of 1:1 conduction was seen in three cases and 2:1 atrioventricular conduction in one (all four had supraventricular tachycardia, confirmed by intracardiac electrocardiography in three). Evidence of retrograde block was seen in 12 (all had ventricular tachycardia, with electrophysiological confirmation in 10). Satisfactory views of the mitral valve were obtained in all patients. Patients with ventricular tachycardia had a variable mitral valve opening time (range 42-110%) compared with those who had supraventricular tachycardia (9-15%). Aortic root and left atrial views gave direct evidence of atrial contraction in three cases, and subcostal right atrial wall views were diagnostic in four of five cases. Seven patients with ventricular tachycardia had been wrongly diagnosed elsewhere as having supraventricular tachycardia. This study confirms that echocardiography is a simple and rapid aid to accurate diagnosis in patients with broad QRS complex tachycardia. Images PMID:4015926

Wren, C; Campbell, R W; Hunter, S

1985-01-01

38

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

39

Hints of Correlation between Broad-line and Radio Variations for 3C 120  

NASA Astrophysics Data System (ADS)

In this paper, we investigate the correlation between broad-line and radio variations for the broad-line radio galaxy 3C 120. By the z-transformed discrete correlation function method and the model-independent flux randomization/random subset selection (FR/RSS) Monte Carlo method, we find that broad H? line variations lead the 15 GHz variations. The FR/RSS method shows that the H? line variations lead the radio variations by a factor of ?ob = 0.34 ± 0.01 yr. This time lag can be used to locate the position of the emitting region of radio outbursts in the jet, on the order of ~5 lt-yr from the central engine. This distance is much larger than the size of the broad-line region. The large separation of the radio outburst emitting region from the broad-line region will observably influence the gamma-ray emission in 3C 120.

Liu, H. T.; Bai, J. M.; Wang, J. M.; Li, S. K.

2014-01-01

40

WPVS 007: Dramatic Broad Absorption Line Variability in a Narrow-line Seyfert 1  

NASA Astrophysics Data System (ADS)

Blue-shifted broad absorption lines are the manifestation of gaseous outflows in astrophysical phenomena. In active galaxies, these outflowing winds may play a key role in the central engine physics by removing angular momentum and in influencing host galaxy evolution by imparting energy and chemically enriched gas to the surrounding medium. AGN wind variability affords us a valuable tool to study this still poorly understood phenomenon. The existence of a high velocity broad line outflow in WPVS007 is especially extraordinary, as Seyfert-luminosity active galaxies are unexpected to produce them. With its lower luminosity and compact size, the NLS1 galaxy WPVS007 (M_V=-19.7, z=0.02882) provides us the ability to study even colossal variability on merely human timescales. Since its 1996 FOS observation, displaying miniBALs but no true broad absorption lines, WPVS007 has experienced a short but rich history of UV BAL variability. By the 2003 FUSE observation, WPVS007 had developed a BAL with v_max ~ 6000km/s, indicating an optically thick, high velocity outflow. We present the 2010 and 2013 June and December HST COS spectra. Between 2003 and 2010, both the maximum and minimum outflow velocity had increased substantially. As of 2013 June, the continuum emission has since dimmed by a factor of ~2 and the BALs have appeared to weaken, with both decreased maximum and minimum velocities. Such dramatic shifts in BAL velocity are unprecedented, as BAL variability is typically confined to changes in optical depth. What is the nature of the variability in this BAL wind? The upcoming (as of the writing of this abstract) December observation should give us more insight into tackling that question, whether it be the transient response of a continuous flow to a fluctuating continuum or perhaps the continued decline of a discrete outflow event.

Cooper, Erin M.; Leighly, K.; Hamann, F. W.; Grupe, D.; Dietrich, M.

2014-01-01

41

The Broad- and Narrow-Line Regions of Narrow-Line Seyfert 1 Galaxies  

NASA Astrophysics Data System (ADS)

We have studied the H? region of six narrow-line Seyfert 1 (NLS1) galaxies. In most cases, the H? profile is best fitted by a combination of a Lorentzian (FWHM ~1100--1250kms-1) and a narrow Gaussian (FWHM ~400kms-1), however, multiple Gaussians can also be adjusted. We have estimated the contribution of the narrow-line region to the total H? by decomposing it into Lorentzians and Gaussians such that the narrowest component has similar width to that of the [O iii] ?5007 line. The strength of the forbidden line ([O iii] ?5007) relative to the narrow component of H? (H?n) seems to be weaker in the NLS1s compared to that of Seyfert 2s. The absolute luminosities of [O iii] ?5007 of NLS1s and broad-line Seyfert 1s (BLS1s) are indistinguishable. This suggests that [O iii] ?5007 emission in NLS1s is not intrinsically weaker than that of BLS1s and the low [O iii] ?5007 / H?n of NLS1s could be due to the presence of H ii regions in the central kpc region. The overall properties of the BLR and the anti-correlation between the soft X-ray slope and H? width found in NLS1s can be understood in terms of dotM / dotMEdd.

Dewangan, G. C.; Singh, K. P.; Chavushyan, V.; Valdes, J. R.

42

Are the broad optical Balmer lines in PG 1613+658 from the central accretion disc?  

NASA Astrophysics Data System (ADS)

In this letter, we report on the positive correlations between the broad-line width and broad-line flux for the broad Balmer lines of the active galactic nucleus (AGN) PG 1613+658, which has been observed for a long time. Rather than the expected negative correlations that come with the widely accepted virialization assumption for AGN broad emission-line regions (BLRs), the positive correlations indicate very different BLR structures of PG 1613+658 from the commonly considered BLR structures that are dominated by the equilibrium between radiation pressure and gas pressure. Therefore, it is preferable to assume that the observed broad single-peaked optical Balmer lines of PG 1613+658 originate from the accretion disc, because the mainly gravity-dominated disc-like BLRs with radial structures have few effects from radiation pressure.

Zhang, Xue-Guang

2015-02-01

43

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

44

Crossing a Broad Gray Line to Help Children  

ERIC Educational Resources Information Center

Helping students with mental health issues sometimes presents teachers with the dilemma of following the letter of school rules or doing what is best for the child. One teacher tells her story of crossing such lines, but only in service to children. She also outlines what teachers can and should do to help students who need mental health services.

Allen, Megan M.

2015-01-01

45

The Broad-Line Region in Active Galactic Nuclei  

E-print Network

after the discovery of quasars and 60 years after the publication of C.K. Seyfert's initial observations unresolved in even the nearest AGNs and the information in line profiles, sampling only one of six dimensions, 28]. Photoionization equilibrium is attained when the rate of photoionization is balanced by the rate

Peterson, Bradley M.

46

Broad-band X-ray spectrum of the newly discovered broad-line radio galaxy IGR J21247+5058  

NASA Astrophysics Data System (ADS)

In this paper, we present radio and high-energy observations of the INTEGRAL source IGR J21247+5058, a broad line emitting galaxy obscured by the Galactic plane. Archival Very Large Array radio data indicate that IGR J21247+5058 can be classified as an Faranoff-Riley type II Broad-Line Radio Galaxy. The spectrum between 610 MHz and 15 GHz is typical of synchrotron self-absorbed radiation with a peak at 8 GHz and a low-energy turnover; the core fraction is 0.1 suggestive of a moderate Doppler boosting of the base of the jet. The high-energy broad-band spectrum was obtained by combining XMM-Newton and Swift/X-Ray Telescope (XRT) observation with INTEGRAL/Image on Board Integral Satellite (IBIS) data. The 0.4-100-keV spectrum is well described by a power law, with slope ? = 1.5, characterized by complex absorption due to two layers of material partially covering the source and a high-energy cut-off around 70-80 keV. Features such as a narrow iron line and a Compton reflection component, if present, are weak, suggesting that reprocessing of the power-law photons in the accretion disc plays a negligible role in the source.

Molina, M.; Giroletti, M.; Malizia, A.; Landi, R.; Bassani, L.; Bird, A. J.; Dean, A. J.; de Rosa, A.; Fiocchi, M.; Panessa, F.

2007-12-01

47

On X-ray variability in narrow-line and broad-line active galactic nuclei  

NASA Astrophysics Data System (ADS)

We assembled a sample of broad-line and narrow-line active galactic nuclei (AGNs) observed by ASCA, the excess variances of which have been determined. The central black hole masses in this sample can be obtained from the reverberation mapping method and the width of the H? emission line. Using the black hole masses and the bolometric luminosity, the Eddington ratio (the ratio of the ionizing luminosity to the Eddington luminosity) can also be obtained. We confirmed the strong anticorrelation between X-ray variability and the central black hole mass found by Lu & Yu. In addition, we found that narrow-line Seyfert 1 galaxies (NLS1s) also follow this relation, with a larger scatter, and that there is only a weak correlation between the X-ray variability and the Eddington ratio, which suggests that rapid variability and narrow lines in NLS1s are mainly due to small central black holes in NLS1s, not the difference of circumnuclear gas around NLS1s. A strong correlation was found between the hard X-ray photon index and the Eddington ratio. If the suggestion of two distinct accretion classes [namely advection-dominated accretion flow (ADAF) and thin disc accretion] in AGNs is correct, the strong correlation between the photon index and the Eddington ratio shows that there exists a kind of two-zone accretion disc, in which the outer zone is a thin disc and the inner zone is an ADAF disc. Otherwise, the accretion process is thin disc accretion and ADAF accretion is not required.

Bian, W.; Zhao, Y.

2003-07-01

48

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

49

Broad forbidden Ne III line emission and intermediate-density gas around QSO nuclei  

NASA Technical Reports Server (NTRS)

A broad emission feature, with a velocity width of the order of 5000 km/s, has been observed near rest wavelength 3870 A in the spectra of three low-redshift QSOs. The line is identified as forbidden Ne III 3869. This broad line may have varied over a time scale of two years, indicating that clouds of intermediate density between 10 to the 8th and 10 to the 11th/cu cm may coexist in the broad-line region. Such clouds would be optically thin, highly ionized, and subject to rapid destruction by radiation pressure.

Zheng, Wei; Burbridge, E. Margaret; Smith, Harding E.

1990-01-01

50

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

51

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

52

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

53

Geometry and Kinematics in the Central Broad-Line Region of a Seyfert 1 Galaxy  

E-print Network

We recorded spectra of the highly variable Seyfert 1 galaxy Mrk110 in a variability campaign with the 9.2m Hobby-Eberly Telescope at McDonald Observatory in order to study the detailed line profile variations of the broad emission lines. Here we show that only an AGN model predicting the formation of the broad Hb line emission in the wind of an accretion disk matches the observed 2-D variability pattern. Furthermore, we derive an improved mass of the central supermassive black hole of M = 1.0(+1.0,-0.5)E7 M_sun from the Hb velocity-delay map.

Kollatschny, W

2002-01-01

54

Geometry and Kinematics in the Central Broad-Line Region of a Seyfert 1 Galaxy  

E-print Network

We recorded spectra of the highly variable Seyfert 1 galaxy Mrk110 in a variability campaign with the 9.2m Hobby-Eberly Telescope at McDonald Observatory in order to study the detailed line profile variations of the broad emission lines. Here we show that only an AGN model predicting the formation of the broad Hb line emission in the wind of an accretion disk matches the observed 2-D variability pattern. Furthermore, we derive an improved mass of the central supermassive black hole of M = 1.0(+1.0,-0.5)E7 M_sun from the Hb velocity-delay map.

W. Kollatschny; K. Bischoff

2002-03-14

55

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

56

The FR II Broad-Line Seyfert 1 Galaxy: PKS J1037-2705  

NASA Astrophysics Data System (ADS)

In this article we demonstrate that PKS J1037-2705 has a weak accretion flow luminosity, well below the Seyfert 1/QSO dividing line, weak broad emission lines (BELs), and moderately powerful FR II extended radio emission. It is one of the few documented examples of a broad-line object in which the time-averaged jet kinetic luminosity, Q, is larger than the total thermal luminosity (IR to X-ray) of the accretion flow, Lbol. The blazar nucleus dominates the optical and near-ultraviolet emission and is a strong source of hard X-rays. The strong blazar emission indicates that the relativistic radio jet is presently active. The implication is that even weakly accreting AGNs can create powerful jets. Kinetically dominated (Q>Lbol) broad-line objects provide important constraints on the relationship between the accretion flow and the jet production mechanism.

Punsly, Brian; Clarke, Tracy E.; Tingay, Steven; Gutiérrez, Carlos M.; Rasmussen, Jesper; Colbert, Ed

2008-11-01

57

Unusual Broad-line Mg II Emitters among Luminous Galaxies in the Baryon Oscillation Spectroscopic Survey  

NASA Astrophysics Data System (ADS)

Many classes of active galactic nuclei (AGNs) have been observed and recorded since the discovery of Seyfert galaxies. In this paper, we examine the sample of luminous galaxies in the Baryon Oscillation Spectroscopic Survey. We find a potentially new observational class of AGNs, one with strong and broad Mg II ?2799 line emission, but very weak emission in other normal indicators of AGN activity, such as the broad-line H?, H?, and the near-ultraviolet AGN continuum, leading to an extreme ratio of broad H?/Mg II flux relative to normal quasars. Meanwhile, these objects' narrow-line flux ratios reveal AGN narrow-line regions with levels of activity consistent with the Mg II fluxes and in agreement with that of normal quasars. These AGN may represent an extreme case of the Baldwin effect, with very low continuum and high equivalent width relative to typical quasars, but their ratio of broad Mg II to broad Balmer emission remains very unusual. They may also be representative of a class of AGN where the central engine is observed indirectly with scattered light. These galaxies represent a small fraction of the total population of luminous galaxies (sime 0.1%), but are more likely (about 3.5 times) to have AGN-like nuclear line emission properties than other luminous galaxies. Because Mg II is usually inaccessible for the population of nearby galaxies, there may exist a related population of broad-line Mg II emitters in the local universe which is currently classified as narrow-line emitters (Seyfert 2 galaxies) or low ionization nuclear emission-line regions.

Roig, Benjamin; Blanton, Michael R.; Ross, Nicholas P.

2014-02-01

58

The dust origin of the Broad Line Region and the model consequences for AGN unification scheme  

NASA Astrophysics Data System (ADS)

We propose a very simple physical mechanism responsible for the formation of the Low Ionization Line part of the Broad Line Region in Active Galactic Nuclei. It explains the scaling of the Broad Line Region size with the monochromatic luminosity, including the exact slope and the proportionality constant, seen in the reverberation studies of nearby sources. The scaling is independent from the mass and accretion rate of an active nucleus. The mechanism predicts the formation of a dust-driven wind in the disk region where the local effective temperature of a non-illuminated accretion disk drops below 1000 K and allows for dust formation. We explore now the predictive power of the model with the aim to differentiate between this model and the previously proposed mechanisms of the formation of the Broad Line Region. We discuss the expected departures from the universal scaling at long wavelength, and the role of the inclination angle of the accretion disk in the source. We compare the expected line profiles with Mg II line profiles in the quasars observed by us with the SALT telescope. We also discuss the tests based on the presence or absence of the broad emission lines in low luminosity active galaxies. Finally, we discuss the future tests of the model to be done with expected ground-based observations and satellite missions.

Czerny, Bo?ena; Modzelewska, Justyna; Petrogalli, Francesco; Pych, Wojtek; Adhikari, Tek P.; ?ycki, Piotr T.; Hryniewicz, Krzysztof; Krupa, Magdalena; ?wie?o?, Agnieszka; Niko?ajuk, Marek

2015-04-01

59

Broad Balmer-Line Absorption in SDSS J172341.10+555340.5  

NASA Astrophysics Data System (ADS)

We present the discovery of Balmer-line absorption from H? to H9 in an iron low-ionizaton broad absorption line (FeLoBAL) quasar, SDSS J172341.10+555340.5, by near-infrared spectroscopy with the Cooled Infrared Spectrograph and Camera for OHS (CISCO) attached to the Subaru Telescope. The redshift of the Balmer-line absorption troughs is 2.0530±0.0003, and it is blueshifted by 5370 km s-1 from the Balmer emission lines. It is more than 4000 km s-1 blueshifted from the previously known UV absorption lines. We detected relatively strong (EWrest = 20 Å) [OIII] emission lines that are similar to those found in other broad absorption line quasars with Balmer-line absorption. We also derived the column density of neutral hydrogen of 5.2 × 1017 cm-2 by using the curve of growth and taking account of Ly? trapping. We searched for UV absorption lines that had the same redshift with Balmer-line absorption, and found Ali III and Fe III absorption lines at z = 2.053 that correspond to previously unidentified absorption lines, and the presence of other blended troughs that were difficult to identify.

Aoki, Kentaro

2010-10-01

60

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

61

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

NASA Astrophysics Data System (ADS)

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

Balmaverde, B.; Capetti, A.

2014-03-01

62

Are strongly variable Seyfert 2 galaxies really AGN without a Broad Line Region?  

NASA Astrophysics Data System (ADS)

Strong amplitude optical brightness variability has been found in a sample of Seyfert 2 galaxies ("Naked AGN", Hawkins 2004). The variability suggests that the nuclear source is seen directly, contradicting the complete absence of broad emission lines as simple Unified Models for AGN would predict. Alternatively the Broad Line Region might be missing in these sources. The proposed XMM-Newton observations offer a priviledged window into the central engine to understand the absorption properties of these objects and compare them to their optical appearance.

Panessa, Francesca

2005-10-01

63

DISENTANGLING THE CIRCUMNUCLEAR ENVIRONS OF CENTAURUS A. II. ON THE NATURE OF THE BROAD ABSORPTION LINE  

SciTech Connect

We report on atomic gas (H I) and molecular gas (as traced by CO(2-1)) redshifted absorption features toward the nuclear regions of the closest powerful radio galaxy, Centaurus A (NGC 5128). Our H I observations using the Very Long Baseline Array allow us to discern with unprecedented sub-parsec resolution H I absorption profiles toward different positions along the 21 cm continuum jet in the inner 0.''3 (or 5.4 pc). In addition, our CO(2-1) data obtained with the Submillimeter Array probe the bulk of the absorbing molecular gas with little contamination by emission, which was not possible with previous CO single-dish observations. We shed light on the physical properties of the gas in the line of sight with these data, emphasizing the still open debate about the nature of the gas that produces the broad absorption line ({approx}55 km s{sup -1}). First, the broad H I line is more prominent toward the central and brightest 21 cm continuum component than toward a region along the jet at a distance {approx}20 mas (or 0.4 pc) further from the nucleus. This indicates that the broad absorption line arises from gas located close to the nucleus, rather than from diffuse and more distant gas. Second, the different velocity components detected in the CO(2-1) absorption spectrum match well with other molecular lines, such as those of HCO{sup +}(1-0), except the broad absorption line that is detected in HCO{sup +}(1-0) (and most likely related to that of the H I). Dissociation of molecular hydrogen due to the active galactic nucleus seems to be efficient at distances r {approx}< 10 pc, which might contribute to the depth of the broad H I and molecular lines.

Espada, D.; Matsushita, S.; Sakamoto, K. [Academia Sinica, Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Peck, A. B. [Joint ALMA Office, Av. El Golf 40, Piso 18, Las Condes, Santiago (Chile); Henkel, C. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany); Iono, D. [Nobeyama Radio Observatory, NAOJ, Minamimaki, Minamisaku, Nagano, 384-1305 (Japan); Israel, F. P. [Sterrewacht Leiden, Leiden University, Postbus 9513, 2300 RA Leiden (Netherlands); Muller, S. [Onsala Space Observatory, SE-43992 Onsala (Sweden); Petitpas, G. [Harvard-Smithsonian Center for Astrophysics, Submillimeter Array, 645 North A'ohoku Place, Hilo, HI 96720 (United States); Pihlstroem, Y.; Taylor, G. B. [Department of Physics and Astronomy, MSC07 4220, University of New Mexico, Albuquerque, NM 87131 (United States); Trung, D. V., E-mail: despada@cfa.harvard.ed [Center for Quantum Electronics, Institute of Physics, Vietnam Academy of Science and Technology, 10 DaoTan, ThuLe, BaDinh, Hanoi (Viet Nam)

2010-09-01

64

Broad-band X-ray spectrum of the newly discovered broad-line radio galaxy IGR J21247+5058  

Microsoft Academic Search

In this paper, we present radio and high-energy observations of the INTEGRAL source IGR J21247+5058, a broad line emitting galaxy obscured by the Galactic plane. Archival Very Large Array radio data indicate that IGR J21247+5058 can be classified as an Faranoff-Riley type II Broad-Line Radio Galaxy. The spectrum between 610 MHz and 15 GHz is typical of synchrotron self-absorbed radiation

M. Molina; M. Giroletti; A. Malizia; R. Landi; L. Bassani; A. J. Bird; A. J. Dean; A. de Rosa; M. Fiocchi; F. Panessa

2007-01-01

65

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

66

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

67

Broad-line region size and black hole mass in high-z AGN  

Microsoft Academic Search

In this contribution we briefly review the reverberation mapping technique and its results for low and intermidiate luminosity AGNs. Then we present a monitoring campaign of high-luminosity high-redshift quasars which will extend these results by two orders of magnitude, probing the broad-line region size and black hole (BH) mass of luminous AGN at redshift ~2-3.

Ismael Botti; Paulina Lira; Hagai Netzer; Shai Kaspi; Jose Maza; Dan Maoz

2008-01-01

68

The spectrum of the Broad Line Region and the high-energy emission of powerful blazars  

E-print Network

High-energy emission (from the X-ray through the gamma-ray band) of Flat Spectrum Radio Quasars is widely associated with the inverse Compton (IC) scattering of ambient photons, produced either by the accretion disk or by the Broad Line Region, by high-energy electrons in a relativistic jet. In the modelling of the IC spectrum one usually adopts a simple black-body approximation for the external radiation field, though the real shape is probably more complex. The knowledge of the detailed spectrum of the external radiation field would allow to better characterize the soft-medium X-ray IC spectrum, which is crucial to address several issues related to the study of these sources. Here we present a first step in this direction, calculating the IC spectra expected by considering a realistic spectrum for the external radiation energy density produced by the BLR, as calculated with the photoionization code CLOUDY. We find that, under a wide range of the physical parameters characterizing the BLR clouds, the IC spectrum calculated with the black-body approximation reproduces quite well the exact spectrum for energies above few keV. In the soft energy band, instead, the IC emission calculated using the BLR emission shows a complex shape, with a moderate excess with respect to the approximate spectrum, which becomes more important for decreasing values of the peak frequency of the photoionizing continuum. We also show that the high-energy spectrum shows a marked steepening, due to the energy dependence of the scattering cross section, above a characteristic energy of 10-20 GeV, quasi independent on the Lorentz factor of the jet.

F. Tavecchio; G. Ghisellini

2008-02-06

69

Broad Emission Line Regions in Active Galactic Nuclei: The Link with the Accretion Power.  

PubMed

We present a model that relates the width of the broad emission lines of active galactic nuclei (AGNs) to the Keplerian velocity of an accretion disk at a critical distance from the central black hole. This critical distance falls in a region bounded on the inward side by the transition radius between the radiation pressure- and the gas pressure-dominated region of the accretion disk and on the outward side by the maximum radius below which a stabilizing, radially accreting and vertically outflowing corona exists. We show that in the framework of this picture, the observed range of Hbeta FWHMs from broad-line to narrow-line type 1 AGNs is well reproduced as a function of the accretion rate. This interval of velocities is the only permitted range and goes from approximately 20,000 km s-1 for sub-Eddington accretion rates to approximately 1000 km s-1 for Eddington accretion rates. PMID:10655166

Nicastro

2000-02-20

70

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

71

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

72

What Do the Ultraviolet Spectra of Narrow-Line Seyfert 1 Galaxies Tell Us about Their Broad-Line Regions?  

NASA Astrophysics Data System (ADS)

We study the UV spectra of narrow-line Seyfert 1 (NLSy1) galaxies and compare them with ``normal'' active galactic nuclei. Similar to their optical lines, the NLSy1s show narrower UV lines. They are also characterized by weaker C IV ?1549 and C III] ?1909 and stronger Al III ?1857 emission. These UV-line properties add to the optical and X-ray properties known to be part of the Boroson & Green eigenvector 1. We show that the steep soft X-rays, which characterize the NLSy1s SEDs, change the equilibrium of the two-phase cloud-intercloud medium, resulting in somewhat higher broad-line region cloud densities, lower ionization parameter, and larger broad-line region radii. These modified conditions can explain the unusual emission-line properties we find in NLSy1. Using a specific model of an accretion disk with corona presented by Witt, Czerny, & ?ycki, we also show that the steep soft and hard X-ray continua can be explained if the L/LEdd ratios are larger than in ``normal'' Sy1s/QSOs, strengthening earlier suggestions that the L/LEdd is the physical parameter driving this eigenvector.

Kuraszkiewicz, Joanna; Wilkes, Belinda J.; Czerny, Bo?ena; Mathur, Smita

2000-10-01

73

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

SciTech Connect

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

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

2009-08-20

74

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

75

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

76

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

77

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

78

Probing broad-line region of the weak line quasar SDSS J094533.99+100950.1  

NASA Astrophysics Data System (ADS)

SDSS J094533.99+100950.1 is a weak line quasar (WLQ) characterised by a low equivalent widths of the high-ionization emission lines such as CIV or HeII, typical iron emission, radio quiescence and X-ray weakness. In our work we tried to answer the question if it is possible that observed emission is intrinsically weak and come from not fully developed broad emission-line region (BELR). We also analyse the observed continuum to check if it is able to ionize a BELR gas and reproduce a weakness of emission-lines or this spectral feature can be simply explained by an intrinsic absorption. Our conclusion is that the minimal active galactic nuclei (AGN) engine consisting of an unobscured accretion disk with a partially ionized gas just expanding from the disk atmosphere is enough to explain observed features of SDSS J094533.99+100950.1.

Hryniewicz, K.; Niko?ajuk, M.; Czerny, B.

2012-07-01

79

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

80

THE SIZE, STRUCTURE, AND IONIZATION OF THE BROAD-LINE REGION IN NGC 3227  

SciTech Connect

Hubble Space Telescope spectroscopy of the Seyfert 1.5 galaxy, NGC 3227, confirms previous reports that the broad H{alpha} emission line flux is time variable, decreasing by a modest {approx}11% between 1999 and 2000 in response to a corresponding {approx}37% decrease in the underlying continuum. Modeling the gas distribution responsible for the broad H{alpha}, H{beta}, and H{gamma} emission lines favors a spherically symmetric inflow as opposed to a thin disk. Adopting a central black hole mass of 7.6 Multiplication-Sign 10{sup 6} M {sub Sun }, determined from prior reverberation mapping, leads to the following dimensions for the size of the region emitting the broad H{alpha} line: an outer radius {approx}90 lt-days and an inner radius {approx}3 lt-days. Thus, the previously determined reverberation size for the broad-line region (BLR) consistently coincides with the inner radius of a much larger volume of ionized gas. However, the perceived size of the BLR is an illusion, a consequence of the fact that the emitting region is ionization bounded at the outer radius and diminished by Doppler broadening at the inner radius. The actual dimensions of the inflow remain to be determined. Nevertheless, the steady-state mass inflow rate is estimated to be {approx}10{sup -2} M {sub Sun} yr{sup -1} which is sufficient to explain the X-ray luminosity of the active galactic nucleus (AGN) in terms of radiatively inefficient accretion. Collectively, the results challenge many preconceived notions concerning the nature of BLRs in AGNs.

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

2013-02-10

81

Water diffusion in zeolite 4A beds measured by broad-line magnetic resonance imaging  

Microsoft Academic Search

Broad-line magnetic resonance imaging has been used to monitor water transport in beds of industrial grade zeolite 4A. Diffusion profiles as a function of time have been obtained for a series of temperatures in the range 20-70 °C. The dynamics is observed to be strongly non-Fickian. A model based on coupled diffusion equations for the vapor in the interparticle space

P. D. M. Hughes; P. J. McDonald; M. R. Halse; B. Leone; E. G. Smith

1995-01-01

82

Timing and Broad Band Pulse Phase Resolved Spectroscopy of VELA X-1: Confirmation of Cyclotron Lines  

Microsoft Academic Search

We propose repeated observations of the high-mass X-ray binary Vela X-1 during one binary orbit, deriving detailed pulse profiles and spectra at each observation. Main goals of this proposal are: (a) the confirmation of cyclotron line features around 27 keV and 55 keV reported from GINGA and HEXE observations; (b) detailed analysis of broad band spectral variations with pulse phase;

Peter Kretschmar

1996-01-01

83

Heating of dust in the broad-line regions of active galaxies and quasars  

SciTech Connect

In this paper we discuss the relevant energy sources which heat (and, in many cases, destroy) the dust grains in the emission-line clouds (ELCs) which give rise to the broad-line emission seen in active extragalactic objects. We compare the heating rates from the external radiation field, trapped line radiation, and the diffuse bound-free continua. We find that in hot clouds (T/sub e/ = 1.5 x 10/sup 4/ K) Ly..cap alpha.. dominates the dust heating rate, while in cooler clouds (T/sub e/ = 1.0 x 10/sup 4/ K) the external radiation field dominates. In all cases, the dust residing in the broad-line clouds is quite hot (T>500 K). These results are discussed in light of the observed infrared properties of active galaxies and quasars, and the following conclusions are reached: (1) If the infrared emission of Seyfert 1 galaxies is primarily thermal in origin, then the redder near-IR colors distinguishing the Seyfert 1 galaxies from the Seyfert 2 galaxies may be understood in terms of the broad-line regions (BLR) concentrating hot dust within the inner parsec of the of the nucleus. (2) Substantial near-infrared dust emission may originate in the neutral regions of the ELCs with only minor accompanying reddening of the hydrogen Balmer lines, since dust confined to the neutral zone reddens only lines emitted from the back side of the cloud. (3) If the broad-line regions of the quasars are characterized by hotter temperatures than Seyfert 1 galaxies, dust may not be able to exist in this region, thereby explaining the apparent lack of thermal dust emission in quasars. (4) Because of the cooling times of the ELCs, near-IR variability due to changes in the dust temperature is dominated by light travel considerations. (5) The present calculations suggest that the dust-to-gas mass ratio in the BLRs of Seyfert 1 galaxies is substantially smaller than the value of 0.01 typically found in our Galaxy.

Rudy, R.J.; Puetter, R.C.

1982-12-01

84

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

NASA Technical Reports Server (NTRS)

High signal-to-noise long-slit spectra have been obtained of the giant H II region NGC 2363 located in the dwarf SBm galaxy NGC 2366. A discovery of low-intensity broad spectral components (FWHM is approximately equal to 40 A or 2400 km/s) in the bright nebular lines H-alpha, H-beta, and forbidden O III is reported. The broad spectral components are detected over a large spatial extent (not less than 500 pc) centered on the nebula. Several mechanisms for broadening nebular lines are explored: stellar winds, Thomson scattering by hot gas, supernova remnants, and superbubble blowout. All mechanisms have problems. Superbubble blowout, which is the only known mechanism capable of accelerating interstellar gas over such a volume of space, does not appear consistent with the physical properties of the H II region NGC 2363 or with the nature of the host galaxy. It is concluded that the broad nebular lines are probably due to very high velocity gas whose origin is, at present, unknown.

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

1992-01-01

85

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

PubMed Central

Efforts to design an effective antibody-based vaccine against HIV-1 would benefit from understanding how germ-line B-cell receptors (BCRs) recognize the HIV-1 gp120/gp41 envelope spike. Potent VRC01-like (PVL) HIV-1 antibodies derived from the VH1-2*02 germ-line allele target the conserved CD4 binding site on gp120. A bottleneck for design of immunogens capable of eliciting PVL antibodies is that VH1-2*02 germ-line BCR interactions with gp120 are uncharacterized. Here, we report the structure of a VH1-2*02 germ-line antibody alone and a germ-line heavy-chain/mature light-chain chimeric antibody complexed with HIV-1 gp120. VH1-2*02 residues make extensive contacts with the gp120 outer domain, including all PVL signature and CD4 mimicry interactions, but not critical CDRH3 contacts with the gp120 inner domain and bridging sheet that are responsible for the improved potency of NIH45-46 over closely related clonal variants, such as VRC01. Our results provide insight into initial recognition of HIV-1 by VH1-2*02 germ-line BCRs and may facilitate the design of immunogens tailored to engage and stimulate broad and potent CD4 binding site antibodies. PMID:23524883

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

2013-01-01

86

RADIO PROPERTIES OF LOW-REDSHIFT BROAD-LINE ACTIVE GALACTIC NUCLEI INCLUDING EXTENDED RADIO SOURCES  

SciTech Connect

We present a study of the extended radio emission in a sample of 8434 low-redshift (z < 0.35) broad-line active galactic nuclei (AGNs) from the Sloan Digital Sky Survey. To calculate the jet and lobe contributions to the total radio luminosity, we have taken the 846 radio core sources detected in our previous study of this sample and performed a systematic search in the FIRST database for extended radio emission that is likely associated with the optical counterparts. We found that 51 out of 846 radio core sources have extended emission (>4'' from the optical AGN) that is positively associated with the AGN, and we have identified an additional 12 AGNs with extended radio emission but no detectable radio core emission. Among these 63 AGNs, we found 6 giant radio galaxies, with projected emission exceeding 750 kpc in length, and several other AGNs with unusual radio morphologies also seen in higher redshift surveys. The optical spectra of many of the extended sources are similar to those of typical broad-line radio galaxy spectra, having broad H{alpha} emission lines with boxy profiles and large M{sub BH}. With extended emission taken into account, we find strong evidence for a bimodal distribution in the radio-loudness parameter R ({identical_to}{nu}{sub radio} L{sub radio}/{nu}{sub opt} L{sub opt}), where the lower radio luminosity core-only sources appear as a population separate from the extended sources, with a dividing line at log(R) {approx}1.75. This dividing line ensures that these are indeed the most radio-loud AGNs, which may have different or extreme physical conditions in their central engines when compared to the more numerous radio-quiet AGNs.

Rafter, Stephen E. [Also at Physics Department, the Technion, Haifa 32000, Israel. (Israel); Crenshaw, D. Michael [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States); Wiita, Paul J., E-mail: rafter@physics.technion.ac.il [Also at Department of Physics, College of New Jersey, Ewing, NJ 08628, USA. (United States)

2011-03-15

87

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

88

Variable X-ray Absorption in the Mini-broad Absorption Line Quasar PG 1126-041  

NASA Astrophysics Data System (ADS)

We present the results of a multi-epoch observational campaign on the mini-broad absorption line quasar (mini-BAL QSO) PG 1126-041 performed with XMM-Newton from 2004 to 2009. Time-resolved X-ray spectroscopy and simultaneous UV and X-ray photometry were performed on the most complete set of observations and on the deepest X-ray exposure of a mini-BAL QSO to date. Complex X-ray spectral variability, found on time scales of both months and hours, is best reproduced by means of variable and massive ionized absorbers along the line of sight. In the highest signal-to-noise observation, highly-ionized X-ray absorbing material outflowing much faster (?out˜ 16500 km s-1) than the UV absorbing one (?out˜ 5000 km s-1) is detected. This highly-ionized absorber is found to be variable on very short time scales of a few hours.

Giustini, M.; Cappi, M.; Chartas, G.; Dadina, M.; Eracleous, M.; Ponti, G.; Proga, D.; Tombesi, F.; Vignali, C.; Palumbo, G. G. C.

2012-08-01

89

Accretion disk wind in the AGN broad-line region: Spectroscopically resolved line profile variations in Mrk110  

E-print Network

Detailed line profile variability studies of the narrow line Seyfert 1 galaxy Mrk110 are presented. We obtained the spectra in a variability campaign carried out with the 9.2m Hobby-Eberly Telescope at McDonald Observatory. The integrated Balmer and Helium (HeI,II) emission lines are delayed by 3 to 33 light days to the optical continuum variations respectively. The outer wings of the line profiles respond much faster to continuum variations than the central regions. The comparison of the observed profile variations with model calculations of different velocity fields indicates an accretion disk structure of the broad line emitting region in Mrk110. Comparing the velocity-delay maps of the different emission lines among each other a clear radial stratification in the BLR can be recognized. Furthermore, delays of the red line wings are slightly shorter than those of the blue wings. This indicates an accretion disk wind in the BLR of Mrk110. We determine a central black hole mass of M = $1.8\\cdot10^{7} M_{\\odot}$. Because of the poorly known inclination angle of the accretion disk this is a lower limit only.

W. Kollatschny

2003-06-19

90

The high-energy view of the broad-line radio galaxy 3C 111  

NASA Astrophysics Data System (ADS)

We present the analysis of Suzaku and XMM-Newton observations of the broad-line radio galaxy (BLRG) 3C 111. Its high-energy emission shows variability, a harder continuum with respect to the radio-quiet active galactic nucleus population, and weak reflection features. Suzaku found the source in a minimum flux level; a comparison with the XMM-Newton data implies an increase of a factor of 2.5 in the 0.5-10 keV flux, in the 6 months separating the two observations. The iron K complex is detected in both data sets, with rather low equivalent width(s). The intensity of the iron K complex does not respond to the change in continuum flux. An ultrafast, high-ionization outflowing gas is clearly detected in the Suzaku/X-ray Imaging Spectrometer data; the absorber is most likely unstable. Indeed, during the XMM-Newton observation, which was 6 months after, the absorber was not detected. No clear rollover in the hard X-ray emission is detected, probably due to the emergence of the jet as a dominant component in the hard X-ray band, as suggested by the detection above ˜100 keV with the GSO onboard Suzaku, although the present data do not allow us to firmly constrain the relative contribution of the different components. The fluxes observed by the ?-ray satellites CGRO and Fermi would be compatible with the putative jet component if peaking at energies E˜ 100 MeV. In the X-ray band, the jet contribution to the continuum starts to be significant only above 10 keV. If the detection of the jet component in 3C 111 is confirmed, then its relative importance in the X-ray energy band could explain the different observed properties in the high-energy emission of BLRGs, which are otherwise similar in their other multiwavelength properties. Comparison between X-ray and ?-ray data taken at different epochs suggests that the strong variability observed for 3C 111 is probably driven by a change in the primary continuum.

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

2011-12-01

91

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

NASA Technical Reports Server (NTRS)

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

Arav, Nahum; Begelman, Mitchell C.

1994-01-01

92

Magnetic fields of active galactic nuclei and quasars with regions of polarized broad H ? lines  

NASA Astrophysics Data System (ADS)

Estimates of magnetic fields for a number of active galactic nuclei are presented. These estimates are based on the observed polarization degrees and position angles of broad H ? lines and in the nearby continuum and on asymptotic analytical formulas for the Stokes parameters of the radiation emerging from a magnetized accretion disk (the Milne problem in a magnetized atmosphere). The characteristic observed feature of the wavelength dependence of the polarization degree inside the line—a minimum at the center and a fast increase of the position angle from one wing to another—can be explained by the superposition of resonance emission from two or more clouds located in the right (Keplerian velocity directed away from the observer) and left (Keplerian velocity directed toward the observer) parts of the orbit in the rotating magnetized accretion disk. The main component in our mechanism is the azimuthal magnetic field in the disk. The presence of a magnetic field perpendicular to the disk plane (which is usually weaker than the azimuthal field) results in the asymmetry of the distribution of the polarization degree and position angle inside the line. The inferred magnetic field strengths at the galactocentric distances where broad lines are emitted can be used to estimate the magnetic fields in the region of the centermost stable orbit and at the horizon of the central black hole, using the power-law dependence of the magnetic field strength corresponding to the standard model of the accretion disk.

Silant'ev, N. A.; Gnedin, Yu. N.; Buliga, S. D.; Piotrovich, M. Yu.; Natsvlishvili, T. M.

2013-01-01

93

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

NASA Technical Reports Server (NTRS)

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

Beltrametti, M.

1980-01-01

94

The Sloan Digital Sky Survey Reverberation Mapping Project: Rapid CIV Broad Absorption Line Variability  

E-print Network

We report the discovery of rapid variations of a high-velocity CIV broad absorption line trough in the quasar SDSS J141007.74+541203.3. This object was intensively observed in 2014 as a part of the Sloan Digital Sky Survey Reverberation Mapping Project, during which 32 epochs of spectroscopy were obtained with the Baryon Oscillation Spectroscopic Survey spectrograph. We observe significant (>4sigma) variability in the equivalent width of the broad (~4000 km/s wide) CIV trough on rest-frame timescales as short as 1.20 days (~29 hours), the shortest broad absorption line variability timescale yet reported. The equivalent width varied by ~10% on these short timescales, and by about a factor of two over the duration of the campaign. We evaluate several potential causes of the variability, concluding that the most likely cause is a rapid response to changes in the incident ionizing continuum. If the outflow is at a radius where the recombination rate is higher than the ionization rate, the timescale of variability...

Grier, C J; Brandt, W N; Trump, J R; Shen, Yue; Vivek, M; Ak, N Filiz; Chen, Yuguang; Dawson, K; Denney, K D; Jiang, Linhua; Kochanek, C S; McGreer, Ian D; Pâris, I; Peterson, B M; Schneider, D P; Tao, Charling; Wood-Vasey, W M; Bizyaev, Dmitry; Ge, Jian; Kinemuchi, Karen; Oravetz, Daniel; Pan, Kaike; Simmons, Audrey

2015-01-01

95

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

NASA Astrophysics Data System (ADS)

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. Because of its hybrid nature we speculate that FIRST J101614.3+520916 is a typical FR II quasar that 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°. The position angles of the radio jet and optical polarization are not well aligned, differing by ~20°-30°. When combined with the evidence presented by Becker and coworkers 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.

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

2000-11-01

96

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

97

The XMM-Newton view of the broad-line radio galaxy 3C 120  

NASA Astrophysics Data System (ADS)

We present the results of a 127-ks XMM-Newton observation of the broad-line radio galaxy 3C 120 performed simultaneously with RXTE. The data have yielded the highest quality 0.6-10 keV spectrum of a radio-loud active galaxy ever produced. The time-averaged spectrum is Seyfert-like, with a reflection amplitude R~ 0.5, and a neutral Fe K? line with equivalent width ~53 eV. The line is slightly broadened with a FWHM ~ 104 km s-1. This is consistent with arising from an accretion disc radius of >~75 GM/c2 at an inclination angle of ~10°, consistent with the limit of <14° derived from the radio jets. At low energies the spectrum requires excess absorption above the Galactic value and a soft excess that is best fitted with a bremsstrahlung model (kT= 0.3-0.4 keV). The total luminosity in the bremsstrahlung component is just under half of the total hard X-ray luminosity. The emission may originate in either the broad-line region, or in giant HII regions adjacent to the nucleus. Weak OVII and OVIII edges are detected with high precision, suggesting the presence of a warm absorber component. Broad-band 0.6-50 keV fits to the data cannot unambiguously determine the accretion mode in 3C 120. A two-component ionized disc model, with a very highly ionized reflector presumably arising from very close to the black hole, is only a small improvement over a truncated disc model. The strength of the soft X-ray emission features produced by the distant neutral reflector are overpredicted in our solar abundance model, implying that the heavy metal abundance in 3C 120 is subsolar. Both broad-band models could also fit a much shorter archival XMM-Newton observation. The total count rate declined by 20 per cent over the course of the long observation, while small-scale rapid variability was present at the level of a few per cent. A possible increase in the Fe K? line flux, significant at the 90 per cent level, was identified at ~80 ks in the observation. The total unabsorbed luminosity of 3C 120 implies that it is accreting close to its Eddington rate, consistent with a model of a highly ionized thick disc. A possible connection between accretion disc thickness and radio jet production is discussed.

Ballantyne, D. R.; Fabian, A. C.; Iwasawa, K.

2004-11-01

98

The broad-line region and dust torus size of the Seyfert 1 galaxy PGC 50427  

NASA Astrophysics Data System (ADS)

We present the results of three-year monitoring campaigns of the z = 0.024 type 1 active Galactic nucleus (AGN) PGC 50427. Using robotic telescopes of the Universitätssternwarte Bochum near Cerro Armazones in Chile, we monitored PGC 50427 in the optical and near-infrared (NIR). Through the use of photometric reverberation mapping with broad- and narrowband filters, we determine the size of the broad-line emitting region by measuring the time delay between the variability of the continuum and the H? emission line. The H? emission line responds to blue continuum variations with an average rest frame lag of 19.0 ± 1.23 days. Using single epoch spectroscopy obtained with the Southern African Large Telescope (SALT) we determined a broad-line H? velocity width of 1020 km s-1 and in combination with the rest frame lag and adoption of a geometric scaling factor f = 5.5, we calculate a black hole mass of MBH ~ 17 × 106 M?. Using the flux variation gradient method, we separate the host galaxy contribution from that of the AGN to calculate the rest frame 5100 Å luminosity at the time of our monitoring campaign. We measured small luminosity variations in the AGN (~10%) accross the three years of the monitoring campaign. The rest frame lag and the host-subtracted luminosity permit us to derive the position of PGC 50427 in the BLR size - AGN luminosity diagram, which is remarkably close to the theoretically expected relation of R ? L0.5. The simultaneous optical and NIR (J and Ks) observations allow us to determine the size of the dust torus through the use of dust reverberation mapping method. We find that the hot dust emission (~1800 K) lags the optical variations with an average rest frame lag of 46.2 ± 2.60 days. The dust reverberation radius and the nuclear NIR luminosity permit us to derive the position of PGC 50427 on the known ? - MV diagram. The simultaneous observations for the broad-line region and dust thermal emission demonstrate that the innermost dust torus is located outside the BLR in PGC 50427, supporting the unified scheme for AGNs. Based on observations made with the Southern African Large Telescope (SALT).

Pozo Nuñez, F.; Ramolla, M.; Westhues, C.; Haas, M.; Chini, R.; Steenbrugge, K.; Barr Domínguez, A.; Kaderhandt, L.; Hackstein, M.; Kollatschny, W.; Zetzl, M.; Hodapp, K. W.; Murphy, M.

2015-04-01

99

Soft Spectral Energy Distributions in AGN and the "Cooling-Challenged" Broad-line Region  

NASA Astrophysics Data System (ADS)

Broad-line region (BLR) emission should be sensitive to the illuminating spectral energy distribution (SED). Gas illuminated by a soft, UV-dominant SED responds in an interesting way. A lack of high-energy photons means high-ionization line-emission is weak. The HII region is dominated by intermediate-ionization states (Si+2, Fe+2, Al+2). However, the soft SED produces a low electron temperature, resulting in weak emission from these predominately collisionally-excited ions. In the partially-ionized zone, collisionally-excited lines such as MgII ?2800 are also weak, again because of the low temperature. Yet the number of hydrogen ionizations is high, and the energy is deposited primarily in excited states of hydrogen and continuum emission. The principal density diagnostics for BLR gas are provided by semiforbidden lines such as CIIII] ? 1909 from ions that are collisionally deexcited at high density. However, these lines are predicted also to be weak in gas illuminated by a soft SED because of the low electron temperature. These similarities are a consequence of both types of gas being unable to cool ("cooling challenged") by the usual BLR emission. These two cases can be differentiated by the strength of the low-ionization line MgII. This permitted line is not very sensitive to density, but will be weaker in gas illuminated by the soft SED. Other similaries and distinguishing characteristics will be discussed. We show how the unusual optical and UV spectrum of PHL 1181, a luminous, intrinsically X-ray weak, narrow-line Seyfert 1 galaxy, is qualitatively explained by its soft SED, and although its spectrum lacks semiforbidden lines, a high density is not required. We also show that SDSS spectra selected by their MgII equivalent widths show some similarities to PHL 1811. Finally, we demonstrate that transmission of a hard continuum through ionized gas can sometimes soften it sufficiently to produce the characteristic properties outlined above.

Leighly, Karen

2007-05-01

100

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

101

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

102

Spatially Resolving the Kinematics of the <100 {\\mu}as Quasar Broad Line Region using Spectroastrometry  

E-print Network

The broad line region (BLR) of luminous active galactic nuclei (AGN) is a prominent observational signature of the accretion flow around supermassive black holes, which can be used to measure their masses (M_BH) over cosmic history. Due to the calculate the expected spectroastrometric signal of a rotation-dominated BLR for various assumptions about the ratio of random to rotational motions, and the radial distribution of the BLR gas. We show that for hyper-luminous quasars at z < 2.5, the size of the low-ionization BLR can already be constrained with existing telesc...

Stern, Jonathan; Pott, Jörg-Uwe

2015-01-01

103

The Extraordinary Abundances of QSO Broad Absorption Line Regions: A Matter of Novae?  

E-print Network

The broad absorption lines (BALs) of QSOs indicate abundances of heavy elements, relative to hydrogen, that are 1 to 2 orders of magnitude higher than the solar values. In at least one QSO, an especially large enhancement of phosphorus is observed. These abundances resemble those in Galactic novae, and this suggests that novae may produce the BAL gas. The needed rate of nova outbursts may come from single white dwarfs that accrete gas as they pass through a supermassive accretion disk around a central black hole.

Gregory A. Shields

1996-02-23

104

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

105

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

PubMed

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

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

2013-10-01

106

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

107

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

108

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.; Gaskell, C. Martin; Marin, Frédéric

2014-10-01

109

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

SciTech Connect

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

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

2013-10-15

110

UV spectral diagnostics for low redshift quasars: estimating physical conditions and radius of the broad line region  

NASA Astrophysics Data System (ADS)

The UV spectral range (1100-3000 Å) 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.; Sulentic, J. W.; Negrete, C. A.; Dultzin, D.; Del Olmo, A.; Martínez Carballo, M. A.; Zwitter, T.; Bachev, R.

2015-04-01

111

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

112

The environment of active galactic nuclei. I - A two-component broad emission line model  

NASA Astrophysics Data System (ADS)

The interaction of the radiation field, the wind, the star cluster, and the accretion disk is described in a two-component emission model in which the high-ionization broad lines (HILs) are produced in the vicinity of shocks in the wind and the low-ionization lines (LILs) are produced in the outer part of the accretion disk as a result of energy reflected from the flow above the disk. The present model resolves the well-known cloud confinement problem by gravitational confinement for the LILs and by postulating a transient cloud population for the HILs. The model can also explain the systematic velocity shifts noted between the HILs and LILs.

Collin-Souffrin, Suzy; Dyson, J. E.; McDowell, Jonathan C.; Perry, Judith J.

1988-06-01

113

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

114

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

115

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

Microsoft Academic Search

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

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

1985-01-01

116

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

117

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

118

SDSS J1138+3517: a quasar showing remarkably variable broad absorption lines  

NASA Astrophysics Data System (ADS)

We report on the highly variable Si IV and C IV broad absorption lines in SDSS J113831.4+351725.2 across four observational epochs. Using the Si IV doublet components, we find that the blue component is usually saturated and non-black, with the ratio of optical depths between the two components rarely being 2:1. This indicates that these absorbers do not fully cover the line of sight and thus a simple apparent optical depth model is insufficient when measuring the true opacity of the absorbers. Tests with inhomogeneous (power-law) and pure-partial coverage (step-function) models of the absorbing Si IV optical depth predict the most un-blended doublet's component profiles equally well. However, when testing with Gaussian-fitted doublet components to all Si IV absorbers and averaging the total absorption predicted in each doublet, the upper limit of the power-law index is mostly unconstrained. This leads us to favour pure-partial coverage as a more accurate measure of the true optical depth than the inhomogeneous power-law model. The pure-partial coverage model indicates no significant change in covering fraction across the epochs, with changes in the incident ionizing flux on the absorbing gas instead being favoured as the variability mechanism. This is supported by (a) the coordinated behaviour of the absorption troughs, (b) the behaviour of the continuum at the blue end of the spectrum and (c) the consistency of photoionization simulations of ionic column density dependencies on ionization parameter with the observed variations. Evidence from the simulations together with the C IV absorption profile indicates that the absorber lies outside the broad line region, though the precise distance and kinetic luminosity are not well constrained.

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

2015-04-01

119

Differential Microlensing of the Continuum and Broad Emission Lines in SDSS J0924+0219, the Most Anomalous Lensed Quasar  

Microsoft Academic Search

SDSS J0924+0219 is the most glaring example of a gravitational lens with\\u000aanomalous flux ratios: optical broad-band photometry shows image D to be a\\u000afactor of 12 fainter than expected for smooth lens potentials. We report\\u000aspectroscopy showing that the anomaly is present in the broad emission line\\u000aflux ratios as well. There are differences between the emission line and

Charles R. Keeton; Scott Burles; Paul L. Schechter; Joachim Wambsganss

2005-01-01

120

Value and limitations of adenosine in the diagnosis and treatment of narrow and broad complex tachycardias.  

PubMed

The diagnostic and therapeutic potential of intravenous adenosine was studied in 64 patients during 92 episodes of regular sustained tachycardia. In 40 patients who had narrow complex tachycardias (QRS less than 0.12 s) adenosine (2.5-25 mg) restored sinus rhythm in 25 with junctional tachycardias (46 of 48 episodes) and produced atrioventricular block to reveal atrial or sinus tachycardia in 15. In 24 patients with broad complex tachycardias (QRS greater than or equal to 0.12 s) adenosine terminated the tachycardias in six patients and revealed atrial or sinus arrhythmias in four. The tachycardias persisted in 14 patients despite doses up to 20 mg, but adenosine allowed the diagnosis of ventricular tachycardia with retrograde atrial activation in two patients by producing transient ventriculoatrial dissociation. Diagnosis based on adenosine induced atrioventricular nodal block was correct in all patients with narrow complex tachycardias and in 92% of those with broad complex tachycardias, compared with correct electrocardiographic diagnoses in 90% and 75% respectively. Adenosine gave diagnostic information additional to the electrocardiogram in 25%. The response to adenosine in broad complex tachycardias identified those of supraventricular origin with 90% sensitivity, 93% specificity, and 92% predictive accuracy. Adenosine restored sinus rhythm in all patients with junctional reentrant tachycardias, but in 10 (35%) the arrhythmias recurred within two minutes. Symptomatic side effects (dyspnoea, chest pain, flushing, headache) were reported by 40 (63%) patients and, although transient, were severe in 23 (36%). There were ventricular pauses of over 2 s in 16% of patients, the longest pause being 6.1 s. Adenosine is of value in the diagnosis and treatment of narrow and broad complex tachycardias, but its use is limited by symptomatic side effects, a tenfold range in minimal effective dosage, occasional action at sites other than the atrioventricular node, and early recurrence or arrhythmia. PMID:2789911

Rankin, A C; Oldroyd, K G; Chong, E; Rae, A P; Cobbe, S M

1989-09-01

121

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

122

When galaxies collide: understanding the broad absorption-line radio galaxy 4C +72.26  

NASA Astrophysics Data System (ADS)

We present a range of new observations of the `broad absorption-line radio galaxy' 4C +72.26 (z ~ 3.5), including sensitive rest-frame ultraviolet integral field spectroscopy using the Gemini/GMOS-N instrument and Subaru/CISCO K-band imaging and spectroscopy. We show that 4C +72.26 is a system of two vigorously star-forming galaxies superimposed along the line of sight separated by ~1300 +/- 200 km s-1 in velocity, with each demonstrating spectroscopically resolved absorption lines. The most active star-forming galaxy also hosts the accreting supermassive black hole which powers the extended radio source. We conclude that the star formation is unlikely to have been induced by a shock caused by the passage of the radio jet, and instead propose that a collision is a more probable trigger for the star formation. Despite the massive starburst, the ultraviolet-mid-infrared spectral energy distribution suggests that the pre-existing stellar population comprises ~1012Msolar of stellar mass, with the current burst only contributing a further ~2 per cent, suggesting that 4C +72.26 has already assembled most of its final stellar mass.

Smith, D. J. B.; Simpson, C.; Swinbank, A. M.; Rawlings, S.; Jarvis, M. J.

2010-05-01

123

The Formation of Broad Emission Line Regions in Supernova-QSO Wind Interactions  

E-print Network

We show that a cooled region of shocked supernova ejecta forms in a type II supernova-QSO wind interaction, and has a density, an ionization parameter, and a column density compatible with those inferred for the high ionization component of the broad emission line regions in QSOs. The calculations are based on the assumption that the ejecta flow is described initially by a similarity solution investigated by Chevalier (1982) and Nadyozhin (1985) and is spherically symmetric. Heating and cooling appropriate for gas irradiated by a nearby powerful continuum source is included in our model, together with reasonable assumptions for the properties of the QSO wind. The model results are also in agreement with observational correlations and imply reasonable supernova rates.

J. M. Pittard; J. E. Dyson; S. A. E. G. Falle; T. W. Hartquist

2001-07-05

124

Radio ejection and broad forbidden emission lines in the Seyfert galaxy NGC 7674  

NASA Astrophysics Data System (ADS)

The authors have obtained new high-resolution radio observations of NGC 7674, using the European VLBI network and the VLA, and optical spectroscopic observations using the Isaac Newton Telescope. The radio maps reveal a triple radio source with a total angular extent of about 0.7 arcsec, and provide evidence that the radio emission is powered by collimated ejection. In the plane of the sky, the ejection axis appears roughly perpendicular to the galactic rotation axis. Although the dominant radio components are separated by 0.5 arcsec, the broad [O III] ?5007 line emission is confined to within about 0.25 arcsec of the continuum nucleus. The authors discuss possible implications of this result.

Unger, S. W.; Pedlar, A.; Axon, D. J.; Graham, D. A.; Harrison, B. A.; Saikia, D. J.; Whittle, M.; Meurs, E. J. A.; Dyson, J. E.; Taylor, D.

1988-10-01

125

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

126

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

127

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

128

Water diffusion in zeolite 4A beds measured by broad-line magnetic resonance imaging  

NASA Astrophysics Data System (ADS)

Broad-line magnetic resonance imaging has been used to monitor water transport in beds of industrial grade zeolite 4A. Diffusion profiles as a function of time have been obtained for a series of temperatures in the range 20-70 °C. The dynamics is observed to be strongly non-Fickian. A model based on coupled diffusion equations for the vapor in the interparticle space and water within the particles has been developed and shown to be in good agreement with experiment. Values for the intraparticle water diffusion coefficient and the interparticle vapor diffusion coefficient, which can be obtained from the model, and their respective temperature dependencies are in good agreement with other published results.

Hughes, P. D. M.; McDonald, P. J.; Halse, M. R.; Leone, B.; Smith, E. G.

1995-05-01

129

X-ray weak broad-line quasars: absorption or intrinsic X-ray weakness ?  

NASA Astrophysics Data System (ADS)

We propose seven short observations of X-ray weak quasars, with the aim of understanding the origin of their low X-ray to optical ratio. The sources belong to the spectroscopically selected Hamburg Quasar Survey, and have been observed with Chandra and in the optical. They show unusual optical properties (most of them have a red continuum and very high EW broad emission lines), while the nature of their X-ray weakness (intrinsic or due to absorption ?) is not yet clear, because of the low signal-to-noise of the Chandra spectra. Four short observations with XMM-Newton gave the answer for four sources, showing absorption in two cases, and an unabsorbed spectrum in the other two. This shows that XMM-Newton can unveil the nature of the X-ray emission of these sources.

Risaliti, Guido

2005-10-01

130

Thomson Thick X-Ray Absorption in a Broad Absorption Line Quasar, PG 0946+301.  

PubMed

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 greater, similar1024 cm-2) 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. PMID:10770695

Mathur; Green; Arav; Brotherton; Crenshaw; deKool; Elvis; Goodrich; Hamann; Hines; Kashyap; Korista; Peterson; Shields; Shlosman; van Breugel W; Voit

2000-04-20

131

X-ray and soft gamma-ray spectra of broad-line radio galaxies  

NASA Astrophysics Data System (ADS)

We study X-ray and soft gamma-ray spectral properties of nearby broad-line radio galaxies (BLRGs) using data from GingaASCA, OSSE and EXOSAT. The X-ray spectra are well fitted by an intrinsic power-law continuum with an energy index of alpha~0.7, moderately absorbed by a cold medium. In addition, the Ginga spectra show fluorescent Fe Kalpha lines with an average equivalent width of ~100 eV, and, in some cases, Compton reflection humps. However, the latter are significantly weaker than both those seen in radio-quiet Seyfert 1s and those expected if the Fe Kalpha lines were due to reflection. We find that this weakness of reflection cannot be explained by dilution by another continuum component, e.g. from a jet. Some ASCA and EXOSAT spectra show soft X-ray excesses below ~3 keV. When that component is taken into account, the Fe Kalpha lines in the ASCA data are found to be unresolved in most cases, and to have equivalent widths <~200 eV, consistent with the Ginga data. Multiple observations of 3C 382 and 390.3 show the Fe Kalpha line approximately constant in flux but accompanied by strong continuum variations. This indicates the bulk of the line is formed by matter at a distance much larger than an accretion-disc scale, consistent with the ASCA line width measurements. The column density of the matter required to account for the observed line fluxes is N_H>~10^23 cm^-2. Such a medium is in the line of sight of 3C 445, but it has to be out of it in other objects in which the observed N_H are substantially lower. Thus a cold medium with that N_H and covering a large solid angle is common in BLRGs, but in most objects it is out of the line of sight, consistent with the unified AGN model. The spectra of BLRGs break and become softer above ~100 keV, as shown by a simultaneous ASCA/OSSE observation of 3C 120 and by the OSSE spectra being on average much softer than the X-ray spectra. Finally, we find the X-ray and gamma-ray spectral properties of Cen A, a bright narrow-line radio galaxy - alpha~=0.8, no or weak Compton reflection, N_H>~10^23 cm^-2 (which is consistent with its Fe Kalpha line flux), and a high-energy break at ~100 keV - consistent with Cen A being intrinsically very similar to BLRGs studied here, again in agreement with the unified model.

Wozniak, Przemyslaw R.; Zdziarski, Andrzej A.; Smith, David; Madejski, Greg M.; Johnson, W. Neil

1998-09-01

132

Metvan: a novel oxovanadium(IV) complex with broad spectrum anticancer activity.  

PubMed

Among the 25 bis(cyclopentadienyl)vanadium(IV) and 14 oxovanadium(IV) compounds synthesised and evaluated for anticancer activity, bis(4,7-dimethyl-1,10-phenanthroline) sulfatooxovanadium(IV) (metvan) was identified as the most promising multitargeted anticancer vanadium complex with apoptosis-inducing activity. At nanomolar and low micromolar concentrations, metvan induces apoptosis in human leukaemia cells, multiple myeloma cells and solid tumour cells derived from breast cancer, glioblastoma, ovarian, prostate and testicular cancer patients. It is highly effective against cisplatin-resistant ovarian cancer and testicular cancer cell lines. Metvan is much more effective than the standard chemotherapeutic agents dexamethasone and vincristine in inducing apoptosis in primary leukaemia cells from patients with acute lymphoblastic leukaemia, acute myeloid leukaemia or chronic acute myeloid leukaemia. Metvan-induced apoptosis is associated with a loss of mitochondrial transmembrane potential, the generation of reactive oxygen species and depletion of glutathione. Treatment of leukaemia cells from acute lymphoblastic leukaemia, acute myeloid leukaemia and chronic acute myeloid leukaemia patients with metvan inhibits the constitutive expression as well as the gelatinolytic activities of matrix metalloproteinase-9 and -2. Treatment of human malignant glioblastoma and breast cancer cells with metvan at concentrations > 1 microM is associated with a nearly complete loss of the adhesive, migratory and invasive properties of the treated cancer cell populations. Metvan shows favourable pharmacokinetics in mice and does not cause acute or subacute toxicity at the dose levels tested (12.5 - 50 mg/kg). Therapeutic plasma concentrations > or = 5 microM, which are highly cytotoxic against human cancer cells, can be rapidly achieved and maintained in mice for at least 24 h after intraperitoneal bolus injection of a single 10 mg/kg non-toxic dose of metvan. Metvan exhibits significant antitumour activity, delays tumour progression and prolongs survival time in severe combined immunodeficient mouse xenograft models of human malignant glioblastoma and breast cancer. The broad spectrum anticancer activity of metvan together with favourable pharmacodynamic features and lack of toxicity warrants further development of this oxovanadium compound as a new anticancer agent. Metvan could represent the first vanadium complex as an alternative to platinum-based chemotherapy. PMID:12457442

D'Cruz, Osmond J; Uckun, Fatih M

2002-12-01

133

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

134

Grazing incidence broad ion beams for reducing line-edge roughness  

NASA Astrophysics Data System (ADS)

As semiconductor feature sizes continue to decrease, the phenomena of line-edge roughness (LER) becomes more disruptive in chip manufacturing. While many efforts are underway to decrease LER from the photoresist, post-developed smoothing techniques may be required to continue shrinking chip features economically. This paper reports on one such method employing the use of a broad ion beam at grazing incidence along the features. This method smooths relatively long spatial-length LER, a potential advantage over other smoothing techniques that focus on just molecular-scale LER. LER reduction numbers using Ne and Ar beams are reported at both short and long spatial wavelengths. Variables include beam energy, length of time and angular dependence. LER measurements are taken using the Hitachi image-analysis software on top-down analytical scanning electron microscope (SEM) measurements. Line-profile data are taken from cross-sectional SEM photographs. Tests have achieved a reduction in LER from 9.8 ± 0.67 nm to 5.5 ± 0.86 nm for 45 nm critical dimensions using an Ar beam at 500 eV for 6 s at an 85° angle of incidence. A reduction from 10.1 ± 1.07 nm to 6 ± 1.02 nm was shown using an Ar beam at 1000 eV for 4 s at a 60° angle of incidence.

Struck, C. R. M.; Flauta, R.; Neumann, M. J.; Kim, K. N.; Raju, R.; Bristol, R. L.; Ruzic, D. N.

2010-07-01

135

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

136

Hard X-ray Spectra of Broad-line Radio Galaxies  

NASA Astrophysics Data System (ADS)

We present the results of hard-X-ray observations of four broad-line radio galaxies (BLRGs) with the Rossi X-Ray Timing Explorer. The original motivation behind the observations was to search for systematic differences between the BLRGs and their radio-quiet counterparts, the Seyfert galaxies. We do, indeed, find that the Fe K-? lines and Compton ``reflection'' components, which are hallmarks of the X-ray spectra of Seyferts galaxies, are weaker in BLRGs by about a factor of 2. This observational result is in agreement with the conclusions of other recent studies of these objects. We examine several possible explanations for this systematic difference, including beaming of the primary X-rays away from the accretion disk, a low iron abundance, a small solid angle subtended by the disk to the primary X-ray source, and dilution of the observed spectrum by beamed X-rays from the jet. We find that a small solid angle subtended by the disk to the primary X-ray source is a viable and appealing explanation, while all others suffer from drawbacks. We interpret this as an indication of a difference in the inner accretion disk structure between Seyfert galaxies and BLRGs, namely that the inner accretion disks of BLRGs have the form of an ion-supported torus or an advection-dominated accretion flow, which irradiates the geometrically thin outer disk.

Eracleous, M.; Sambruna, R. M.; Mushotzky, R.

137

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

Microsoft Academic Search

We present the results of a uniform and systematic search for blueshifted Fe K absorption lines in the X-ray spectra of five bright broad-line radio galaxies observed with Suzaku. We detect, for the first time in radio-loud active galactic nuclei (AGNs) at X-rays, several absorption lines at energies greater than 7 keV in three out of five sources, namely, 3C

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

2010-01-01

138

BROAD-LINE REVERBERATION IN THE KEPLER-FIELD SEYFERT GALAXY Zw 229-015  

SciTech Connect

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 3 m telescope during the dark runs from 2010 June through December, obtaining 54 spectroscopic observations in total. We have also obtained nightly V-band imaging with the Katzman Automatic Imaging Telescope at Lick Observatory and with the 0.9 m telescope at the Brigham Young University West Mountain Observatory over the same period. We detect strong variability in the source, which exhibited more than a factor of two change in broad H{beta} flux. From cross-correlation measurements, we find that the H{beta} light curve has a rest-frame lag of 3.86{sup +0.69}{sub -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} lag measurement with a broad H{beta} width of {sigma}{sub line} = 1590 {+-} 47 km s{sup -1} measured from the rms variability spectrum, we obtain a virial estimate of M{sub BH} = 1.00{sup +0.19}{sub -0.24} x 10{sup 7} M{sub sun} for the black hole in Zw 229-015. As a Kepler target, Zw 229-015 will eventually have one of the highest-quality optical light curves ever measured for any active galaxy, and the black hole mass determined from reverberation mapping will serve as a benchmark for testing relationships between black hole mass and continuum variability characteristics in active galactic nuclei.

Barth, Aaron J.; Nguyen, My L. [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697-4575 (United States); Malkan, Matthew A. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90024 (United States); Filippenko, Alexei V.; Li, Weidong; Cenko, S. Bradley; Choi, Jieun; Duchene, Gaspard; Ganeshalingam, Mohan [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Gorjian, Varoujan [Jet Propulsion Laboratory, 4800 Oak Grove Boulevard, MS 169-327, Pasadena, CA 91109 (United States); Joner, Michael D. [Department of Physics and Astronomy, N283 ESC, Brigham Young University, Provo, UT 84602-4360 (United States); Bennert, Vardha Nicola [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Botyanszki, Janos; Childress, Michael; Cucciara, Antonino [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Comerford, Julia M. [Astronomy Department, University of Texas at Austin, Austin, TX 78712 (United States); Da Silva, Robert [University of California Observatories/Lick Observatory, Santa Cruz, CA 95064 (United States); Fumagalli, Michele [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Gates, Elinor L. [Lick Observatory, P.O. Box 85, Mount Hamilton, CA 95140 (United States); Gerke, Brian F., E-mail: barth@uci.edu [Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., M/S 29, Menlo Park, CA 94025 (United States)

2011-05-10

139

Broad supernatural punishment but not moralizing high gods precede the evolution of political complexity in Austronesia.  

PubMed

Supernatural belief presents an explanatory challenge to evolutionary theorists-it is both costly and prevalent. One influential functional explanation claims that the imagined threat of supernatural punishment can suppress selfishness and enhance cooperation. Specifically, morally concerned supreme deities or 'moralizing high gods' have been argued to reduce free-riding in large social groups, enabling believers to build the kind of complex societies that define modern humanity. Previous cross-cultural studies claiming to support the MHG hypothesis rely on correlational analyses only and do not correct for the statistical non-independence of sampled cultures. Here we use a Bayesian phylogenetic approach with a sample of 96 Austronesian cultures to test the MHG hypothesis as well as an alternative supernatural punishment hypothesis that allows punishment by a broad range of moralizing agents. We find evidence that broad supernatural punishment drives political complexity, whereas MHGs follow political complexity. We suggest that the concept of MHGs diffused as part of a suite of traits arising from cultural exchange between complex societies. Our results show the power of phylogenetic methods to address long-standing debates about the origins and functions of religion in human society. PMID:25740888

Watts, Joseph; Greenhill, Simon J; Atkinson, Quentin D; Currie, Thomas E; Bulbulia, Joseph; Gray, Russell D

2015-04-01

140

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

NASA Astrophysics Data System (ADS)

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 multi-wavelength 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 (> 1 pc) from the central engine of AGN. This finding may have a strong impact on black hole mass estimates based on measured widths of the broad emission lines and on the gamma-ray emission mechanisms.

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

2015-03-01

141

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

142

Strong Variability of Overlapping Iron Broad Absorption Lines in Five Radio-selected Quasars  

NASA Astrophysics Data System (ADS)

We present a study of the variability of broad absorption lines (BALs) in a uniformly radio-selected sample of 28 BAL quasars using the archival data from the FIRST Bright Quasar Survey and the Sloan Digital Sky Survey as well as data we obtained ourselves, covering timescales of ? 1-10 yr in the quasar rest frame. To our surprise, five quasars exhibiting strong variations all belong to a special subclass of “overlapping-trough” iron low-ionization BAL (OFeLoBAL) quasars; however, four other non-overlapping FeLoBALs (non-OFeLoBALs) are invariant, except in one case with a weak change in optical depth. Meanwhile, we also identify six typical variations of high-ionization and low-ionization BALs in this BAL quasar sample. Photoionization models suggest that OFeLoBALs are formed in relatively dense (ne > 106 cm?3) outflows at distances from the continuum source that range from the subparsec scale to dozens of parseconds. These formation conditions differ from those of non-OFeLoBALs, which are likely produced by low-density gas located at distances of hundreds to thousands of parseconds. Thus, OFeLoBALs and non-OFeLoBALs, i.e., FeLoBALs with/without strong BAL variations, may represent the bimodality of Fe ii absorption; the former are located in active galactic nucleus environments rather than in the host galaxy. We suggest that a high density and a small distance are the necessary conditions for the creation of OFeLoBALs. As suggested in the literature, strong BAL variability is possibly attributable to variability in the covering factor of the BAL regions caused by clouds transiting across the line of sight rather than to variations in ionization.

Zhang, Shaohua; Zhou, Hongyan; Wang, Tinggui; Wang, Huiyuan; Shi, Xiheng; Liu, Bo; Liu, Wenjuan; Li, Zhenzhen; Wang, Shufen

2015-04-01

143

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

144

Complex magnetically insulated transmission line oscillator  

SciTech Connect

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

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

2008-08-15

145

On the origins of C IV absorption profile diversity in broad absorption line quasars  

E-print Network

There is a large diversity in the C IV broad absorption line (BAL) profile among BAL quasars (BALQs). We quantify this diversity by exploring the distribution of the C IV BAL properties, FWHM, maximum depth of absorption and its velocity shift ($v_{\\rm md}$), using the SDSS DR7 quasar catalogue. We find the following: (i) Although the median C IV BAL profile in the quasar rest-frame becomes broader and shallower as the UV continuum slope ($\\alpha_{\\rm UV}$ at 1700-3000 A) gets bluer, the median individual profile in the absorber rest-frame remains identical, and is narrow (FWHM = 3500 km/s) and deep. Only 4 per cent of BALs have FWHM > 10,000 km/s. (ii) As the He II emission equivalent-width (EW) decreases, the distributions of FWHM and $v_{\\rm md}$ extend to larger values, and the median maximum depth increases. These trends are consistent with theoretical models in which softer ionizing continua reduce overionization, and allow radiative acceleration of faster BAL outflows. (iii) As $\\alpha_{\\rm UV}$ become...

Baskin, Alexei; Hamann, Fred

2015-01-01

146

Optical observations of the broad-lined type Ic supernova SN 2012ap  

NASA Astrophysics Data System (ADS)

The optical observations of the type Ic supernova (SN Ic) SN 2012ap in NGC 1729 are presented. A comparison with other SNe Ic indicates that SN 2012ap is highly reddened (with E(B — V)host~0.8 mag) and may represent one of the most luminous SNe Ic ever observed, with an absolute V-band peak magnitude of ~ ?19.3±0.5 mag after extinction correction. The near-maximum-light spectrum shows wide spectral features that are typical of broad-lined SNe Ic. One interesting feature in the spectrum is the appearance of some narrow absorption features that can be attributed to the diffuse interstellar bands, consistent with the large reddening inferred from the photometric method. Based on the light curves and the spectral data, we estimate that SN 2012ap produced a 56Ni mass of ~ 0.3 ± 0.1Msolar 1 in the explosion, with an ejecta mass of 2.4?0.7+0.7Msolar and a kinetic energy of EK = 1.1?0.4+0.4 × 1052 erg. The properties of its progenitor are also briefly discussed.

Liu, Zheng; Zhao, Xu-Lin; Huang, Fang; Wang, Xiao-Feng; Zhang, Tian-Meng; Chen, Jun-Cheng; Zhang, Tong-Jie

2015-02-01

147

A VERY LARGE ARRAY SURVEY OF RADIO-SELECTED SDSS BROAD ABSORPTION LINE QUASARS  

SciTech Connect

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

DiPompeo, M. A.; Brotherton, M. S. [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); Laurent-Muehleisen, Sally [Illinois Institute of Technology, 3101 South Dearborn Street, Chicago, IL 60616 (United States)

2011-12-10

148

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

149

Seven Broad Absorption Line Quasars With Excess Broadband Absorption Near 2250 Å  

NASA Astrophysics Data System (ADS)

We report the discovery of excess broadband absorption (EBBA) near 2250 Å 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? level, with five above \\gt 5? . 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 Å bump seen in the Local Group and may be a counterpart of the 2175 Å bump under different conditions in the early universe. Furthermore, five objects in this sample show low-ionization BAL (LoBALs), such as Mg ii and Al iii, in addition to the high-ionization BAL 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 the bump is still not clear, the coexistence of both BALs and bumps and the significantly high fraction of LoBALs may indicate that the bump carriers are closely related to the early evolution phase of quasars.

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

2015-04-01

150

Broad-Line and Multi-Wave Band Emission from Blazars  

NASA Astrophysics Data System (ADS)

We studied the correlations of the flux of the broad-line emission FBLR) with the X-ray emission flux, optical emission flux at 5500Å and radio emission flux at 5GHz, respectively, for a large sample of 50 blazars [39 flat-spectrum radio quasars (FSRQs) and 11 BLLac objects]. Our main results are as follows. There are very strong correlations between FBLR and FX and between LBLR and LX in both states for 39 FSRQs, and the slopes of the linear-regression equations are almost equal to 1. There are weak correlations between FBLR and FX and between LBLR and LX for 11 BLLac objects in both states, and the slopes of the linear-regression equations are close to 1. There are significant correlations between FBLR and FX and between LBLR and LX for 50 blazars in both states, the slopes of both linear-regression equations are also close to 1. These results support a close link between relativistic jets and accretion onto the central Kerr black hole. On the other hand, we find that BLLac objects have a low accretion efficiency, ?, whereas FSRQs have a high ?. The unified model of FSRQs and BLLac objects is also discussed.

Yi, Tingfeng; Xie, Guangzhong

2008-04-01

151

The ASCA X-Ray Spectrum of the Broad-line Radio Galaxy Pictor A: A Simple Power Law With No Fe K? Line  

NASA Astrophysics Data System (ADS)

We present the X-ray spectrum of the broad-line radio galaxy Pictor A as observed by ASCA in 1996. The main objective of the observation was to detect and study the profiles of the Fe K? lines. The motivation was the fact that the Balmer lines of this object show well-separated displaced peaks, suggesting an origin in an accretion disk. The 0.5-10 keV X-ray spectrum is described very well by a model consisting of a power law of photon index 1.77 modified by interstellar photoelectric absorption. We find evidence for neither a soft nor a hard (Compton reflection) excess. More importantly, we do not detect an Fe K? line, in marked contrast with the spectra of typical Seyfert galaxies and other broad-line radio galaxies observed by ASCA. The 99% confidence upper limit on the equivalent width of an unresolved line at a rest energy of 6.4 keV is 100 eV, while for a broad line (FWHM ~ 60,000 km s-1), the corresponding upper limit is 135 eV. We discuss several possible explanations for the weakness of the Fe K? line in Pictor A paying attention to the currently available data on the properties of Fe K? lines in other broad-line radio galaxies observed by ASCA. We speculate that the absence of a hard excess (Compton reflection) or an Fe K? line is an indication of an accretion disk structure that is different from that of typical Seyfert galaxies, e.g., the inner disk may be an ion torus.

Eracleous, Michael; Halpern, Jules P.

1998-10-01

152

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

153

Broad absorption line quasars with redshifted troughs: high-velocity infall or rotationally dominated outflows?  

NASA Astrophysics Data System (ADS)

We report the discovery in the Sloan Digital Sky Survey (SDSS) and the SDSS-III Baryon Oscillation Spectroscopic Survey of 17 broad absorption line (BAL) quasars with high-ionization troughs that include absorption redshifted relative to the quasar rest frame. The redshifted troughs extend to velocities up to v ? 12 000 km s-1 and the trough widths exceed 3000 km s-1 in all but one case. Approximately 1 in 1000 BAL quasars with blueshifted C IV absorption also has redshifted C IV absorption; objects with C IV absorption present only at redshifted velocities are roughly four times rarer. In more than half of our objects, redshifted absorption is seen in C II or Al III as well as C IV, making low-ionization absorption at least 10 times more common among BAL quasars with redshifted troughs than among standard BAL quasars. However, the C IV absorption equivalent widths in our objects are on average smaller than those of standard BAL quasars with low-ionization absorption. We consider several possible ways of generating redshifted absorption. The two most likely possibilities may be at work simultaneously, in the same objects or in different ones. Rotationally dominated outflows seen against a quasar's extended continuum source can produce redshifted and blueshifted absorption, but variability consistent with this scenario is seen in only one of the four objects with multiple spectra. The infall of relatively dense and low-ionization gas to radii as small as 400 Schwarzschild radii can in principle explain the observed range of trough profiles, but current models do not easily explain the origin and survival of such gas. Whatever the origin(s) of the absorbing gas in these objects, it must be located at small radii to explain its large redshifted velocities, and thus offers a novel probe of the inner regions of quasars.

Hall, P. B.; Brandt, W. N.; Petitjean, P.; Pâris, I.; Filiz Ak, N.; Shen, Yue; Gibson, R. R.; Aubourg, É.; Anderson, S. F.; Schneider, D. P.; Bizyaev, D.; Brinkmann, J.; Malanushenko, E.; Malanushenko, V.; Myers, A. D.; Oravetz, D. J.; Ross, N. P.; Shelden, A.; Simmons, A. E.; Streblyanska, A.; Weaver, B. A.; York, D. G.

2013-09-01

154

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

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

155

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

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

156

Variability of broad emission lines in high-luminosity, high-redshift quasars  

NASA Astrophysics Data System (ADS)

We examine the variability of the high-ionization Ly? ?1216 broad emission line (BEL) in a sample of 61 high-luminosity, high-redshift quasars observed at two epochs by the Sloan Digital Sky Survey. These bright objects lie in the redshift interval z = [2.5, 4.3] and have luminosities 3.4 × 1045 ? ?L? ? 3.4 × 1046erg s-1 at 1450 Å. Utilizing improved spectrophotometric flux calibrations relative to nearby compact stars observed simultaneously, we are able to measure the flux changes in Ly? and the nearby continuum at two epochs. We find 20 objects that exhibit Ly? BEL flux variability at a significance level greater than 5? on time-scales ranging from days to years in the quasar rest frame. The results show that, although some earlier work showed no significant detections of Ly? BEL flux changes in a quasar sample with even higher luminosity, variability is present and readily observable in the sample studied here. We also consider the C IV ?1549 BEL. The lack of a strong correlation between Ly? BEL variability and nearby continuum variability is consistent with the presence of a time lag between the variations, whereas the presence of a stronger correlation between Ly? BEL variability and C IV BEL variability suggests that these BEL regions (BELRs) are at similar distances from the central ionizing source. Some interesting examples are highlighted in the analysis, including a case where the flux of an Ly? BEL increased by ˜26 per cent in 14 d in the quasar rest frame, suggesting that the BELR has the shape of a disc, which is being observed face-on. This work demonstrates that future campaigns of spectrophotometric monitoring can improve our understanding of the structure of the BELRs of high-luminosity, high-redshift quasars.

Woo, Sui Chi; Turnshek, David A.; Badenes, Carles; Bickerton, Steven

2013-09-01

157

The parsec-scale structure of radio-loud broad absorption line quasars  

NASA Astrophysics Data System (ADS)

Context. Broad absorption line quasars (BAL QSOs) belong to a class of objects not well-understood as yet. Their UV spectra show BALs in the blue wings of the UV resonance lines, owing to ionized gas with outflow velocities up to 0.2 c. They can have radio emission that is difficult to characterize and that needs to be studied at various wavelengths and resolutions. Aims: We aim to study the pc-scale properties of their synchrotron emission and, in particular, to determine their core properties. Methods: We performed observations in the Very Long Baseline Interferometry (VLBI) technique, using both the European VLBI Network (EVN) at 5 GHz, and the Very Long Baseline Array (VLBA) at 5 and 8.4 GHz to map the pc-scale structure of the brightest radio-loud objects of our sample, allowing a proper morphological interpretation. Results: A variety of morphologies have been found: 9 BAL QSOs on a total of 11 observed sources have a resolved structure. Core-jet, double, and symmetric objects are present, suggesting different orientations. In some cases the sources can be young GPS or CSS. The projected linear size of the sources, also considering observations from our previous work for the same objects, can vary from tens of pc to hundreds of kpc. In some cases, a diffuse emission can be supposed from the missing flux-density with respect to previous lower resolution observations. Finally, the magnetic field strength does not significantly differ from the values found in the literature for radio sources with similar sizes. Conclusions: These results are not easily interpreted with the youth scenario for BAL QSOs, in which they are generally compact objects still expelling a dust cocoon. The variety of orientations, morphologies, and extensions found are presumably related to different possible angles for the BAL producing outflows, with respect to the jet axis. Moreover, the phenomenon could be present in various phases of the QSO evolution. Table 3 is available in electronic form at http://www.aanda.org

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

2013-06-01

158

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

159

Eddington ratio distribution of X-ray selected broad-line AGNs at 1.0  

NASA Astrophysics Data System (ADS)

We investigate the Eddington ratio distribution of X-ray selected broad-line AGNs in the redshift range 1.0broad-line AGNs in the CDFS, ECDFS, and the XMM-LH surveys. AGNs with similar black hole masses show a broad range of AGN bolometric luminosities, indicating that the accretion efficiency of black holes is widely distributed. We propose that the observed downsizing trend can be interpreted as massive black holes with low accretion rates, which are relatively fainter than less massive black holes with efficient accretion.

Suh, Hyewon

2014-11-01

160

The broad components in the Hff line of very active stars: chromospheric microflaring?  

E-print Network

is asymmetric and the fit is better matched when the broad component is blue­shifted or red­shifted with respect of these events, which indicates that microflares can also affect the solar chromosphere. 1 #12; Figure 1. EZ Peg (right panel). Recently, with high­resolution UV observations obtained with the HST's GHRS, broad

Complutense de Madrid, Universidad

161

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

162

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

163

Orientation dependency of broad-line widths in quasars and consequences for black-hole mass estimation  

E-print Network

In this paper we report new evidence that measurements of the broad-line widths in quasars are dependent on the source orientation, consistent with the idea that the broad-line region is flattened or disc-like. This reinforces the view derived from radio-selected samples, where the radio-core dominance has been used as a measure of orientation. The results presented here show a highly significant (>99.95%) correlation between radio spectral index (which we use as a proxy for source orientation) and broad-line width derived from the H-beta and MgII emission lines. This is the first time that this type of study has used quasars derived from a large optically selected quasar sample, where the radio-loud quasars (RLQs) and radio-quiet quasars (RQQs) have indistinguishable distributions in redshift, bolometric luminosity and colour, and therefore overcomes any biases which may be present in only selecting via radio emission. We find that the mean FWHM for the flat-spectrum radio-loud quasars (FSQs) to be = 4990 +/- 536km/s, which differs significant from the mean FWHM of the steep-spectrum radio-loud quasars (SSQs), where =6464 +/- 506km/s. We also find that the distribution in FWHM for the FSQs is indistinguishable from that of the radio-quiet quasars (RQQs), where = 4831 +/-25km/s. Considering other observational results in the literature we interpret this result in the context of a significant fraction of the FSQs being derived from the underlying RQQ population which have their radio flux Doppler boosted above the RLQ/RQQ divide. Under the assumption of a disc-like broad-line region we find no evidence for a difference in the average line-of-sight angle for RQQs and RLQs, implying that the difference is due to black-hole mass. (abridged)

Matt J. Jarvis; Ross J. McLure

2006-03-09

164

A Simultaneous RXTE and XMM-Newton Observation of the Broad-Line Radio Galaxy 3C 111  

NASA Astrophysics Data System (ADS)

We present the results of simultaneous XMM-Newton and RXTE observations of the broad-line radio galaxy 3C 111. We find that the Compton reflection bump is extremely weak; however, broad residuals are clearly present in the spectrum near the Fe K? emission line region. When fitted with a Gaussian emission line, the feature has an equivalent width of 40-100 eV and FWHM of greater than 20,000 km s-1 however, the exact properties of this weak line are highly dependent on the chosen continuum model. The width of the line suggests an origin in the inner accretion disk, which is, however, inconsistent with the lack of Compton reflection. We find that much of the broad residual emission can be attributed to continuum curvature. The data are consistent with a model in which the primary power-law continuum is reprocessed by an accretion disk that is truncated at small radii. Alternatively, the primary source could be partially covered by a dense absorber. The latter model is less attractive than the former because of the small inclination angle of the jet of 3C 111 to the line of sight. We consider it likely that the curved continuum of the partial covering model is fortuitously similar to the continuum shape of the reprocessing model. In both models, the fit is greatly improved by the addition of an unresolved Fe K? emission line, which could arise in either a Compton-thin obscuring torus or dense clouds lying along the line of sight. We also find that there are unacceptable residuals at low energies in the MOS data in particular, which were modeled as a Gaussian with an energy of ~1.5 keV; we attribute these residuals to calibration uncertainties of the MOS detectors.

Lewis, Karen T.; Eracleous, Michael; Gliozzi, Mario; Sambruna, Rita M.; Mushotzky, Richard F.

2005-04-01

165

Broadband nuclear emission in two radio-loud broad absorption line quasars  

NASA Astrophysics Data System (ADS)

Aims: We present modelling and interpretation of the continuum broadband emission of two broad absorption line (BAL) quasars. The X-ray weakness of BAL quasars in comparison to non-BAL objects is possibly caused by the absorption of X-ray emission by the shielding material near the equatorial plane. On the other hand, the radio-loud BAL quasars are more X-ray loud than the radio-quiet ones. This suggests that part of the X-ray emission may arise from the radio jet. To investigate this possibility, we modelled the nuclear spectra of two BAL quasars in the whole available energy range. Methods: We focus on the emission from the very centres of these two objects, not greater than several parsecs. The source of emission was approximated by a single, homogeneous component that produces synchrotron and inverse-Compton radiation. The simplicity of the model allowed us to estimate the basic physical parameters of the emitting regions, using a universal analytic approach. Such methods have already been proposed to estimate basic physical parameters in blazars. For the first time, in a simplified form we propose this solution for quasars. In addition, we modelled the radiation spectra of the accretion disk and its corona to compare them with the jets' spectra. Results: We find that in the case of radio and X-ray luminous high-redshift object 3C 270.1, the nuclear X-ray continuum is dominated by the non-thermal, inverse-Compton emission from the innermost parts of the radio jet. However, the radio core of the lobe-dominated PG 1004+130 is probably too weak to produce significant part of the observed X-ray emission. A large contribution from the X-ray emitting accretion disk and corona is produced in our model for a sufficiently high mass of the black hole. However, it then exceeds the observed flux. Because the large intrinsic absorption was postulated recently by the NuSTAR observations, we propose that the disk-corona component may still account for the X-rays produced in this source. This part of the spectrum must nevertheless be dominated by the X-ray jet. The results of our modelling show that the jet-linked X-ray emission is present in both strong and weak radio sources, but its fraction seems to scale with the radio jet power. Appendix A is available in electronic form at http://www.aanda.org

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

2015-02-01

166

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

167

AGN Space Telescope and Optical Reverberation Mapping Project. IV. Velocity-Delay Mapping of Broad Emission Lines in NGC 5548  

NASA Astrophysics Data System (ADS)

Two-dimensional velocity-delay maps of AGN broad emission line regions can be recovered by modelling observations of reverberating emission-line profiles on the assumption that the line profile variations are driven by changes in ionising radiation from a compact source near the black hole. The observable light travel time delay resolves spatial structure on iso-delay paraboloids, while the doppler shift resolves kinematic structure along the observer's line-of-sight. Velocity-delay maps will be presented and briefly discussed for the Lyman alpha, CIV and Hbeta line profiles based on the HST and ground-based spectrophotometric monitoring of NGC 5548 during the 2014 AGN STORM campaign.

Horne, Keith D.; Agn Storm Team

2015-01-01

168

Constraining The Abundance Of Massive Black Hole Binaries By Spectroscopic Monitoring Of Quasars With Offset Broad Emission Lines  

NASA Astrophysics Data System (ADS)

A fraction of quasars have long been known to show significant bulk velocity offsets (of a few hundred to thousands of km/s) in the broad permitted emission lines with respect to host galaxy systemic redshift. Various scenarios may explain these features such as massive black hole binaries or broad line region gas kinematics. As previously demonstrated by the dedicated work of Eracleous and colleagues, long-term spectroscopic monitoring provides a promising test to discriminate between alternative scenarios. Here, we present a sample of 300 shifted-line quasars homogeneously selected from the SDSS DR7. For 60 of them, we have conducted second-epoch optical spectra using MMT/BCS, ARC 3.5m/DIS, and/or FLWO 1.5m/FAST. These new observations, combined with the existing SDSS spectra, enable us to constrain the velocity drifts of these shifted broad lines with time baselines of a few years up to a decade. Previous work has been focusing on objects with extreme velocity offsets: > 1000 km/s. Our work extends to the parameter space of smaller velocity offsets, where larger velocity drifts would be expected in the binary scenario. Our results may be used to identify strong candidates for and to constrain the abundance of massive black hole binaries, which are expected in the hierarchical universe, but have so far been illusive.

Liu, Xin; Shen, Y.

2012-05-01

169

Absorption of 10 Gev--1 Tev Gamma Rays by Radiation from Broad-Line Region in 3C 279  

E-print Network

In this paper, we study the photon-photon pair production optical depth for 10 GeV--1 TeV gamma rays from 3C 279 due to the diffuse radiation of broad-line region (BLR). Assuming a power-law spectrum of $E_{\\gamma}^{-a_2}$ for the photon intensity of very high energy (VHE) gamma rays, $a_1 \\gtrsim 405$ and $a_2\\gtrsim 6.4$ are inferred by the integrated photon fluxes measured by MAGIC and HESS. Based on this power-law spectrum, the pre-absorbed spectra are inferred by correcting the photon-photon absorption on the diffuse photons of the BLR (internal absorption) and the extragalactic background light (external absorption). Position of gamma-ray emitting region $R_{\\rm{\\gamma}}$ determines the relative contributions of this two diffuse radiation to the total absorption for 10 GeV--1 TeV gamma rays. The internal absorption could make spectral shape of gamma rays more complex than only corrected for the external absorption, and could lead to the formation of arbitrary softening and hardening gamma-ray spectra. It should be necessary for the internal absorption to be considered in studying 10 GeV--1 TeV gamma rays from powerful blazars. The energies of annihilated gamma-ray photons due to the internal absorption are likely to be mainly reradiated around GeV. Our results indicate that $R_{\\rm{\\gamma}}$ may be between the inner and outer radii of the BLR for 3C 279. This implies for powerful blazars that $R_{\\rm{\\gamma}}$ might be neither inside the BLR cavity nor outside the BLR, but be within the BLR shell. Observations of $\\it GLAST$, MAGIC, HESS, and VERITAS in the near future could give more constraints on the position of the gamma-ray emitting region relative to the BLR.

H. T. Liu; J. M. Bai; L. Ma

2008-07-20

170

The Evolution of Quasar C IV and Si IV Broad Absorption Lines over Multi-year Timescales  

NASA Astrophysics Data System (ADS)

We investigate the variability of C IV ?1549 broad absorption line (BAL) troughs over rest-frame timescales of up to ?7 yr in 14 quasars at redshifts z >~ 2.1. For nine sources at sufficiently high redshift, we also compare the C IV and Si IV ?1400 absorption variation. We compare shorter and longer term variability using spectra from up to four different epochs per source and find complex patterns of variation in the sample overall. The scatter in the change of absorption equivalent width (EW), ?EW, increases with the time between observations. BALs do not, in general, strengthen or weaken monotonically, and variation observed over shorter (lsimmonths) timescales is not predictive of multi-year variation. We find no evidence for asymmetry in the distribution of ?EW that would indicate that BALs form and decay on different timescales, and we constrain the typical BAL lifetime to be gsim30 yr. The BAL absorption for one source, LBQS 0022+0150, has weakened and may now be classified as a mini-BAL. Another source, 1235+1453, shows evidence of variable, blue continuum emission that is relatively unabsorbed by the BAL outflow. C IV and Si IV BAL shape changes are related in at least some sources. Given their high velocities, BAL outflows apparently traverse large spatial regions and may interact with parsec-scale structures such as an obscuring torus. Assuming BAL outflows are launched from a rotating accretion disk, notable azimuthal symmetry is required in the outflow to explain the relatively small changes observed in velocity structure over times up to 7 yr.

Gibson, Robert R.; Brandt, W. N.; Gallagher, S. C.; Hewett, Paul C.; Schneider, Donald P.

2010-04-01

171

Two-Component Structure of the Hbeta Broad-Line Region in Quasars. I. Evidence from Spectral Principal Component Analysis  

E-print Network

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 \\AA. 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, \\emph{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 demonstr...

Hu, Chen; Ho, Luis C; Ferland, Gary J; Baldwin, Jack A; Wang, Ye

2012-01-01

172

Constraints on the broad line region from regularized linear inversion: Velocity-delay maps for five nearby active galactic nuclei  

E-print Network

Reverberation mapping probes the structure of the broad emission-line region (BLR) in active galactic nuclei (AGN). The radius of the BLR along with the virial velocity of the BLR gas can be used to measure the mass of the supermassive black hole. The main systematic uncertainty affecting reverberation mapping is the unknown structure of the BLR. We develop a new method for analysing reverberation mapping data based on regularized linear inversion (RLI) that includes statistical modelling of the AGN continuum light curves. This method enables fast, flexible, and robust calculation of velocity-resolved response maps to probe BLR structure. Contrary to other methods, RLI allows for negative response in the BLR, such as when some areas of the BLR respond in inverse proportion to a change in ionizing continuum luminosity. We present time delays, integrated response functions, and velocity-delay maps for the H{\\beta} broad emission line in five nearby AGN, as well as H{\\alpha} and H{\\gamma} broad emission lines in...

Skielboe, Andreas; Treu, Tommaso; Park, Daeseong; Barth, Aaron J; Bentz, Misty C

2015-01-01

173

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

174

VLA observations of broad 6-cm excited state OH lines in W49A  

E-print Network

Using the Very Large Array (VLA), we observed all three of the 6-cm lines of the doublet Pi 1/2, J=1/2 state of OH with sub-arcsecond resolution (about 0.4 arcsec) in W49A. While the spatial distribution and the range in velocities of the 6-cm lines are similar to those of the ground state (18-cm) OH lines, a large fraction of the total emission in all three 6-cm lines has large linewidths (about 5 -- 10 km/s) and is spatially-extended, very unlike typical ground state OH masers which typically are point-like at VLA resolutions and have linewidths less than 1 km/s. We find brightness temperatures of 5900 K, 4700 K, and greater than 730 K for the 4660-MHz, 4750-MHz, and 4765-MHz lines, respectively. We conclude that these are indeed maser lines. However, the gains are about 0.3, again very unlike the 18-cm lines which have gains greater than 10000. We compare the excited state OH emission with that from other molecules observed with comparable angular resolution to estimate physical conditions in the regions emitting the peculiar, low-gain maser lines. We also comment on the relationship with the 18-cm masers

Patrick Palmer; W. M. Goss

2005-04-05

175

Unsaturated Low-Ionization Broad Absorption Lines in the Quasar SDSS J144842.45+042403.1  

NASA Astrophysics Data System (ADS)

We present a detailed analysis of the exceptional low-ionization broad absorption line (LoBAL) quasar SDSS J144842.45+042403.1. The C IV absorption trough, which is likely saturated, has a box-shaped bottom at a flux level of 2%-5% of the unabsorbed flux. A large fraction of at least 80% of the C IV and Fe II emission-line fluxes are obliterated by the C IV broad absorption lines (BALs), spanning 3000 km s-1 in velocity. This indicates that the outflow intercepts most of the lines of sight to the continuum source and the broad emission line region (BELR). Therefore, the BAL region (BALR) should be located outside the BELR, and its size is no less than that of the BELR. The Al III and Mg II BAL troughs, which are well resolved, are found to be unsaturated and to show the same velocity structures. Meanwhile, their velocities largely overlap that of the C IV BAL, indicating that the LoBALs and the HiBALs (high-ionization BALs) are closely associated and most likely produced from the same outflow. The column densities of the Mg+ and Al2+ ions in the outflow are measured. Results from an X-ray observation performed with Chandra suggest the presence of intrinsic X-ray absorption with a hydrogen column density of 1022-1023 cm-2. The measured Mg+ and Al2+ column densities can be well reproduced in models with a dimensionless ionization parameter of logU>-1.5 and a total hydrogen column density of NH=2.8×1022U cm-2. A comparison of models with the observed properties also suggests that the outflow is either very highly ionized (with a high column density) or clumpy.

Lu, Honglin; Wang, Tinggui; Yuan, Weimin; Dou, Liming; Ge, Jian; Zhou, Hongyan; Wang, Huiyuan; Dong, Xiaobo

2008-06-01

176

Discovery of H alpha absorption in the unusual broad absorption line quasar SDSS J083942.11+380526.3  

E-print Network

We discovered an H alpha absorption in a broad H alpha emission line of an unusual broad absorption line quasar, SDSS J083942.11+380526.3 at z=2.318, by near-infrared spectroscopy with the Cooled Infrared Spectrograph and Camera for OHS (CISCO) on the Subaru telescope. The Presence of non-stellar H alpha absorption is known only in the Seyfert galaxy NGC 4151 to date, thus our discovery is the first case for quasars. The H alpha absorption line is blueshifted by 520 km/s relative to the H alpha emission line, and its redshift almost coincides with those of UV low-ionization metal absorption lines. The width of the H alpha absorption (~ 340 km/s) is similar to those of the UV low-ionization absorption lines. These facts suggest that the H alpha and the low-ionization metal absorption lines are produced by the same low-ionization gas which has a substantial amount of neutral gas. The column density of the neutral hydrogen is estimated to be ~ 10^18 cm^-2 by assuming a gas temperature of 10,000 K from the analysis of the curve of growth. The continuum spectrum is reproduced by a reddened (E(B-V) ~ 0.15 mag for the SMC-like reddening law) composite quasar spectrum. Furthermore, the UV spectrum of SDSS J083942.11+380526.3 shows a remarkable similarity to that of NGC 4151 in its low state, suggesting the physical condition of the absorber in SDSS J083942.11+380526.3 is similar to that of NGC 4151 in the low state. As proposed for NGC 4151, SDSS J083942.11+380526.3 may be also seen through the close direction of the surface of the obscuring torus.

Kentaro Aoki; Ikuru Iwata; Kouji Ohta; Masataka Ando; Masayuki Akiyama; Naoyuki Tamura

2006-07-04

177

Discovery of H? Absorption in the Unusual Broad Absorption Line Quasar SDSS J083942.11+380526.3  

NASA Astrophysics Data System (ADS)

We discovered H? absorption in the broad H? emission line of an unusual broad absorption line quasar, SDSS J083942.11+380526.3, at z=2.318, through near-infrared spectroscopy with the Cooled Infrared Spectrograph and Camera for OHS (CISCO) on the Subaru telescope. The presence of nonstellar H? absorption is known only in the Seyfert galaxy NGC 4151 to date; thus, our discovery is the first case for quasars. The H? absorption line is blueshifted by 520 km s-1 relative to the H? emission line, and its redshift almost coincides with those of UV low-ionization metal absorption lines. The width of the H? absorption (~340 km s-1) is similar to those of the UV low-ionization absorption lines. These facts suggest that the H? and low-ionization metal absorption lines are produced by the same low-ionization gas, which has a substantial amount of neutral gas. The column density of the neutral hydrogen is estimated to be ~1018 cm-2 by assuming a gas temperature of 10,000 K from the analysis of the curve of growth. The continuum spectrum is reproduced by a reddened [E(B-V)~0.15 mag for the SMC-like reddening law] composite quasar spectrum. Furthermore, the UV spectrum of SDSS J083942.11+380526.3 shows a remarkable similarity to that of NGC 4151 in its low state, suggesting that the physical condition of the absorber in SDSS J083942.11+380526.3 is similar to that of NGC 4151 in the low state. As proposed for NGC 4151, SDSS J083942.11+380526.3 may also be seen through the edge of the obscuring torus. Based in part on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

Aoki, Kentaro; Iwata, Ikuru; Ohta, Kouji; Ando, Masataka; Akiyama, Masayuki; Tamura, Naoyuki

2006-11-01

178

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

179

Microlensing of the Broad Emission Line Region in the Quadruple Lens SDSS J1004+4112  

Microsoft Academic Search

We present seven epochs of spectroscopy on the quadruply imaged quasar SDSS J1004+4112, spanning observed-frame time delays from 1 to 322 days. The spectra reveal differences in the emission lines between the lensed images. Specifically, component A showed a strong enhancement in the blue wings of several high-ionization lines relative to component B, which lasted at least 28 days (observed

Gordon T. Richards; Charles R. Keeton; Bartosz Pindor; Joseph F. Hennawi; Patrick B. Hall; Edwin L. Turner; Naohisa Inada; Masamune Oguri; Shin-Ichi Ichikawa; Robert H. Becker; Michael D. Gregg; Richard L. White; J. Stuart B. Wyithe; Donald P. Schneider; David E. Johnston; Joshua A. Frieman; J. Brinkmann

2004-01-01

180

The evolution of the broad-line region among SDSS quasars  

Microsoft Academic Search

Based on 5344 quasar spectra taken from the SDSS Data Release 2, the dependences of various emission-line flux ratios on redshift and quasar luminosity are investigated in the ranges 2.0 <= z = MB >= -29.5. We show that the emission lines in the composite spectra are fitted better with power-law profiles than with double Gaussian or modified Lorentzian profiles,

Tohru Nagao; Alessandro Marconi; Roberto Maiolino

2006-01-01

181

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

SciTech Connect

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

None

2000-02-01

182

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

SciTech Connect

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

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

2011-05-10

183

X-ray and soft gamma-ray spectra of Broad-Line Radio Galaxies  

E-print Network

We study X-ray and soft gamma-ray spectral properties of BLRGs using data from Ginga, ASCA, OSSE and EXOSAT. The X-ray spectra are well fitted by an intrinsic power-law continuum with an energy index of alpha ~ 0.7, moderately absorbed by a cold medium. In addition, the Ginga spectra show Fe K-alpha lines with an average equivalent width of ~ 100 eV, and, in some cases, Compton reflection humps. However, the latter components are significantly weaker than both those seen in radio-quiet Seyferts and those expected if the Fe K-alpha lines were due to reflection. Some ASCA and EXOSAT spectra show soft X-ray excesses below ~ 3 keV. When that component is taken into account, the Fe K-alpha lines in the ASCA data become unresolved with equivalent widths 10^23 cm^-2. Such a medium is in the line-of-sight in 3C 445 but it has to be out of it in other objects, in which the observed N_H are substantially lower. Thus, a cold medium with that N_H and covering a large solid angle is out of the line-of-sight in most objects. The spectra of BLRGs break and become softer above ~ 100 keV, as shown by a simultaneous ASCA/OSSE observation of 3C 120 and by the OSSE spectra being on average much softer than the X-ray spectra. Finally, we find the X-ray and gamma-ray spectral properties of Cen A intrinsically very similar to BLRGs studied here.

Przemyslaw R. Wozniak; Andrzej A. Zdziarski; David Smith; Greg M. Madejski; W. Neil Johnson

1998-05-12

184

The Nature of the Broad--Line--Region in the Radio--Loud AGN 3C390.3  

E-print Network

We present an analysis of the ultraviolet and X-Ray variability of the Broad- Line-Radio Galaxy 3C390.3 over 15 years. The UV continuum showed large variations with amplitudes of up to a factor of 10. We find: (1) The variations of CIV and Ly_alpha are highly correlated with the UV continuum, and are delayed with respect to the continuum variations by 50-110 days with the red wing of both CIV and Ly_alpha , leading the blue wing; (2) The CIV/Ly_alpha ratio is positively correlated with both the continuum flux and UV line strength, a behavior different from other AGNs studied so far; (3) The blue sides of the Ly_alpha and CIV profiles are similar to the blue side of the Balmer lines, while the red sides are different, suggesting a different origin for the red peak in the Balmer lines. Our results suggest: (1) The broad CIV and Ly_alpha emitting gas is infalling towards the central object; (2) The overall behaviour of the CIV/Ly_alpha ratio and the absence of a big blue bump, strongly indicate the coexistence of optically thick as well as optically thin BLR clouds; (3) Assuming circular symmetry and predominantly circular motion, the BLR gas is situated at 83$\\pm$25 lightdays from the central source; (4) Under these assumptions and with the derived circular velocity of $v_{rot} \\simeq$ 2850 km s$^{-1}$, the central mass inside this radius is confined to $1.3~10^8 M\\odot < M_{CM}< 4.0~10^8 M\\odot$; (6) Comparing our results with those obtained from VLBI and observations of the Fe $K\\alpha$ line, suggests the association of the BLR with a disk, inclined at 98$\\pm$12 degrees with respect to the direction of superluminal motion of the radio blobs.

Willem Wamsteker; Wang Ting-gui; Norbert Schartel; Roberto Vio

1997-03-13

185

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

186

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

187

Diagnostic Power of Broad Emission Line Profiles in Searches for Binary Supermassive Black Holes.  

NASA Astrophysics Data System (ADS)

Motivated by advances in observational searches for sub-parsec supermassive black hole binaries (SBHBs) made in the past few years we develop a semi-analytic model to describe the spectral emission line signatures of these systems. The goal of this work is to test one of the leading models of binary accretion flows in the literature: SBHB in a circumbinary disk. In this context, we model SBHB accretion flows as a set of three accretion disks: two mini-disks that are gravitationally bound to the individual black holes and a circumbinary disk that forms a common envelope about a gravitationally bound binary. We find that emission line profiles tend to have different statistical properties depending on the semi-major axis, mass ratio, eccentricity of the binary, and the alignment of the triple-disk system, and can in principle be used to infer the statistical distribution of these parameters.

Nguyen, Khai; Bogdanovic, Tamara

2015-01-01

188

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

SciTech Connect

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

None

2000-02-01

189

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

190

A robust ultra-broad-band wireless communication system using SAW chirped delay lines  

Microsoft Academic Search

Design and performance of a low-cost wireless communication system for indoor and industrial environments are presented. The system is based on chirp-signal transmission to achieve a robust communication link. For the chirp expansion and compression, surface acoustic wave chirped delay lines fabricated from LiTaO3-X112rotY are used. Center frequency, bandwidth, and chirp rate are 348.8 MHz, 80 MHz, and ±40 MHz\\/?s,

Andreas Springer; Mario Huemer; Leonhard Reindl; Clemens C. W. Ruppel; Alfred Pohl; Franz Seifert; Wolfgang Gugler; Robert Weigel

1998-01-01

191

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

PubMed Central

Purpose Cleidocranial dysplasia is an autosomal dominant disorder characterized by defective ossification of the intramembraneous ossification (primarily the clavicles, cranium, and pelvis), and it is caused by mutations in the RUNX2 gene that is responsible for osteoblast differentiation. Spine deformities were of progressive nature and considered to be the major orthopedic abnormalities encountered in our practice in patients with cleidocranial dysplasia. We aimed to further delineate the underlying spine pathology and its etiological understanding. Extraspinal deformities were dealt with respectively. Material and methods In this paper, we describe 7 patients who were consistent with the phenotypic and the genotypic characterization of cleidocranial dysplasia. Reformatted computed tomography (CT) scans have been applied in several instances to further understand the underlying pathology of progressive spine tilting. Radiographs were sufficient to illustrate other skeletal malformations. Results Anatomical survey demonstrates that a broad spectrum of frequently unrecognized orthopedic aberrations were encountered. We believe that torticollis has evolved in connection with the persistence of synchondrosis of the skull base and the upper cervical spine and these are strongly correlated to the well-known pathology of posterior occipital synchondrosis. Similarly, scoliosis and kyphoscoliosis resulted from the pathologic aberration of the cartilaginous stage of disrupted embryological development. All our results are discussed for the first time. Coxa vara, patellar dysplasia, and genu valgum were observed as extraspinal deformities. Conclusion This paper includes for the first time the anatomical analysis of the malformation complex of the craniocervical and the entire spine in patients with cleidocranial dysplasia. Reformatted CT scan was the modality of choice. We were able to illustrate that the persistence of skull base and the cervical spine synchondrosis were correlated with the pathological mechanism of the posterior occipital synchondrosis. Therefore, injuries to the craniocervical region in these patients might lead to a wide range of dreadful complications, ranging from complete atlanto-occipital or atlanto-axial dislocation to nondisplaced occipital condyle avulsion fractures with the possibility of morbid and or mortal outcome. On the other hand, the persistence of a cartilaginous spine was the reason behind the progressive spine tilting. This pathological form can be considered as a notoriously unpredictable malformation complex. The value of presenting these patients is to demonsterate that the genotype is not a precise index to assess the severity and the natural history of the phenotype. PMID:24023524

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

2013-01-01

192

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

E-print Network

products containing milk. Nonfat dry milk, cheese and whey products together make up about halfGlobal trade in dairy products involves complex and con- tentious issues. Viewed broadly from. International trade in dairy products is small relative to production and is highly concentrated. Among major

Radeloff, Volker C.

193

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

194

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

195

The Formation of Broad Emission Line Regions in Supernova-QSO Wind Interactions II. 2D Calculations  

E-print Network

One aspect of supernova remnant evolution that is relatively unstudied is the influence of an AGN environment. A high density ambient medium and a nearby powerful continuum source will assist the cooling of shocked ejecta and swept-up gas. Motion of the surrounding medium relative to the remnant will also affect the remnant morphology. In an extension to previous work we have performed 2D hydrodynamical calculations of SNR evolution in an AGN environment, and have determined the evolutionary behaviour of cold gas in the remnant. The cold gas will contribute to the observed broad line emission in AGNs, and we present preliminary theoretical line profiles from our calculations. A more detailed comparison with observations will be performed in future work. The SNR-AGN interaction may be useful as a diagnostic of the AGN wind.

J. M. Pittard; J. E. Dyson; S. A. E. G. Falle; T. W. Hartquist

2003-09-03

196

GeV BREAKS IN BLAZARS AS A RESULT OF GAMMA-RAY ABSORPTION WITHIN THE BROAD-LINE REGION  

SciTech Connect

Spectra of the brightest blazars detected by the Fermi Gamma-ray Space Telescope Large Area Telescope cannot be described by a simple power-law model. A much better description is obtained with a broken power law, with the break energies of a few GeV. We show here that the sharpness and the position of the breaks can be well reproduced by absorption of {gamma}-rays via photon-photon pair production on He II Lyman recombination continuum and lines. This implies that the blazar zone lies inside the region of the highest ionization of the broad-line region (BLR) within a light-year from a super-massive black hole. The observations of {gamma}-ray spectral breaks open a way of studying the BLR photon field in the extreme-UV/soft X-rays, which are otherwise hidden from our view.

Poutanen, Juri; Stern, Boris, E-mail: juri.poutanen@oulu.f, E-mail: boris.stern@gmail.co [Astronomy Division, Department of Physics, P.O. Box 3000, 90014 University of Oulu, Oulu (Finland)

2010-07-10

197

Implications of the broad Al-26 1809 keV line observed by GRIS  

NASA Technical Reports Server (NTRS)

The astrophysical implications of the large width of the 1809 keV gamma ray line from the decay of radioactive Al-26, recently observed with the gamma ray imaging spectrometer (GRIS), are discussed. While there may be no apparent single mechanism that can explain the observed broadening, high speed dust grains, extremely hot superbubbles and a large, low density gaseous halo were identified in the Galactic center region as the possible origins. The implications of these observations on the hot gas content in the interstellar medium are discussed.

Chen, Wan; Diehl, Roland; Gehrels, Neil; Hartmann, Dieter; Leising, Mark; Naya, Juan E.; Prantzos, Nikos; Tueller, Jack; vanBallmoos, Peter

1997-01-01

198

TRANSIENT SUPERSTRONG CORONAL LINES AND BROAD BUMPS IN THE GALAXY SDSS J074820.67+471214.3  

SciTech Connect

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]{lambda}6376, [Fe XI]{lambda}7894, [Fe XIV]{lambda}5304, [S XII]{lambda}7612, and [Ar XIV]{lambda}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 ({sigma} {approx} 120-240 km s{sup -1}) are much broader than the narrow emission lines ({sigma} {approx} 40 km s{sup -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]{lambda}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 10{sup 42} erg s{sup -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 Tinggui; Zhou Hongyan; Lu Honglin [Key Laboratory for Research in Galaxies and Cosmology, Chinese Academy of Sciences, University of Sciences and Technology of China (USTC), Hefei, Anhui 230026 (China); Wang Lifan [Department of Physics, Texas A and M University, College Station, TX 77843 (United States); Xu Dawei, E-mail: twang@ustc.edu.cn [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China)

2011-10-20

199

Constraints on Black Hole Spin in a Sample of Broad Iron Line AGN  

NASA Technical Reports Server (NTRS)

We present a uniform X-ray spectral analysis of nine type-1 active galactic nuclei (AGN) that have been previously found to harbor relativistically broadened iron emission lines. We show that the need for relativistic effects in the spectrum is robust even when one includes continuum "reflection" from the accretion disk. We then proceed to model these relativistic effects in order to constrain the spin of the supermassive black holes in these AGN. Our principal assumption, supported by recent simulations of geometrically-thin accretion disks, is that no iron line emission (or any associated Xray reflection features) can originate from the disk within the innermost stable circular orbit. Under this assumption, which tends to lead to constraints in the form of lower limits on the spin parameter, we obtain non-trivial spin constraints on five AGN. The spin parameters of these sources range from moderate (a approximates 0.6) to high (a > 0.96). Our results allow, for the first time, an observational constraint on the spin distribution function of local supermassive black holes. Parameterizing this as a power-law in dimensionless spin parameter (f(a) varies as absolute value of (a) exp zeta), we present the probability distribution for zeta implied by our results. Our results suggest 90% and 95% confidence limits of zeta > -0.09 and zeta > -0.3 respectively.

Brenneman, Laura W.; Reynolds, Christopher S.

2008-01-01

200

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

NASA Technical Reports Server (NTRS)

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

Vio, Roberto; Horne, Keith; Wamsteker, Willem

1994-01-01

201

The Differences in the Torus Geometry between Hidden and Non-hidden Broad Line Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGNs) with clumpy torus models. We compiled high spatial resolution (?0.3–0.7 arcsec) mid-IR (MIR) N-band spectroscopy, Q-band imaging, and nuclear near- and MIR photometry from the literature. Combining these nuclear near- and MIR observations, far-IR photometry, and clumpy torus models enables us to put constraints on the torus properties and geometry. We divide the sample into three types according to the broad line region (BLR) properties: type-1s, type-2s with scattered or hidden broad line region (HBLR) previously observed, and type-2s without any published HBLR signature (NHBLR). Comparing the torus model parameters gives us the first quantitative torus geometrical view for each subgroup. We find that NHBLR AGNs have smaller torus opening angles and larger covering factors than HBLR AGNs. This suggests that the chance to observe scattered (polarized) flux from the BLR in NHBLR could be reduced by the dual effects of (a) less scattering medium due to the reduced scattering volume given the small torus opening angle and (b) the increased torus obscuration between the observer and the scattering region. These effects give a reasonable explanation for the lack of observed HBLR in some type-2 AGNs.

Ichikawa, Kohei; Packham, Christopher; Ramos Almeida, Cristina; Asensio Ramos, Andrés; Alonso-Herrero, Almudena; González-Martín, Omaira; Lopez-Rodriguez, Enrique; Ueda, Yoshihiro; Díaz-Santos, Tanio; Elitzur, Moshe; Hönig, Sebastian F.; Imanishi, Masatoshi; Levenson, Nancy A.; Mason, Rachel E.; Perlman, Eric S.; Alsip, Crystal D.

2015-04-01

202

Structure of the Accretion Flow in Broad-Line Radio Galaxies: The Case of 3C 390.3  

NASA Astrophysics Data System (ADS)

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? emission line at 6.4 keV with equivalent width (EW) = 40 eV. The Fe K? line has a width FWHM ~ 8800 km s-1, consistent within a factor of 2 with the width of the double-peaked H? 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-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 ? = 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 ? ~ 2700 erg cm s-1 the inner radius of the ionized reflector is constrained to be larger than 20rG , 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 20rG 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.; Reeves, J. N.; Braito, V.; Lewis, K. T.; Eracleous, M.; Gliozzi, M.; Tavecchio, F.; Ballantyne, D. R.; Ogle, P. M.; Barth, A. J.; Tueller, J.

2009-08-01

203

Measured Metallicities at the Sites of Nearby Broad-Lined Type Ic Supernovae and Implications for the SN-GRB Connection  

E-print Network

We compare the chemical abundances at the sites of 12 nearby (z Ic supernovae (SN Ic) that showed broad lines, but had no observed Gamma-Ray Burst (GRB), with the chemical abundances in 5 nearby (z Ic were seen after the fireball had faded. It has previously been noted that GRB hosts are low in luminosity and low in their metal abundances. If low metallicity is sufficient to force the evolution of massive stars to end their lives as GRB with an accompanying broad-lined SN Ic, then we would expect higher metal abundances for the broad-lined SN Ic that have no detected GRB. This is what we observe, and this trend is independent of the choice of metallicity calibration we adopt, and the mode of SN survey that found the broad-lined SN. A unique feature of this analysis is that we present new spectra of the host galaxies and analyze all the measurements of both samples in the same set of ways, using the galaxy emission-line measurements corrected for extinction and stellar absorption, via independent metallicity diagnostics of Kewley & Dopita (2002), of McGaugh (1991) and of Pettini & Pagel (2004). In our small sample, the boundary between galaxies that have GRB accompanying their broad-lined SN Ic and those that have broad-lined SN Ic without a GRB lies at an oxygen abundance of 12+log(O/H)_KD02 ~ 8.5, which corresponds to 0.2-0.6 Z_sun depending on the adopted metallicity scale and solar abundance value. Even when we limit the comparison to SN Ic that were found in untargeted supernova surveys, the environment of every broad-lined SN Ic that had no GRB is more metal rich than the site of any broad-lined SN Ic where a GRB was detected.

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

2007-12-19

204

1E 0104.2 + 3153 - A broad absorption-line QSO viewed through a giant elliptical galaxy  

NASA Technical Reports Server (NTRS)

The optical identification of the X-ray source 1E 0104.2 + 3153 is complicated by the close projection of a broad absorption-line (BAL) QSO (z = 2.027) 10 arcsec from a giant elliptical galaxy (z = 0.111) at the center of a compact group of galaxies. At only 1.2 de Vaucouleur radii (16 kpc for H sub 0 = 100 km/s Mpc) this QSO-galaxy projection is the closest yet discovered. Based upon current observations, the source of the X-ray emission cannot be conclusively determined. Present in the BAL QSO spectrum are extremely strong Ca II H and K absorption lines due to the intervening galaxy, the first optical detection of the cold interstellar medium in an elliptical galaxy. The strength of these lines (EW = 2 and 1 A) requires observation through several interstellar clouds in the line of sight to the QSO. By its proximity to the central regions of the elliptical galaxy and the relative distances of the galaxy and QSO, this QSO is a particularly good candidate for observing dramatic transient gravitational lensing phenomena due to halo stars in the foreground galaxy.

Stocke, J. T.; Liebert, J.; Schild, R.; Gioia, I. M.; Maccacaro, T.

1984-01-01

205

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

206

Gamma-ray lines from the Orion complex  

NASA Technical Reports Server (NTRS)

We show that the 4.44 and 6.13 MeV line emission observed with the Compton Telescope (COMPTEL) from Orion is consistent with gamma-ray spectra consisting of a mixture of narrow and broad lines or spectra containing only broad lines. We employed several accelerated particle compositions and showed that the current COMPTEL data in the 3-7 MeV region alone cannot distinguish between the various possibilities. However, the COMPTEL upper limits in the 1-3 MeV band favor a composition similar to that of the winds of Wolf-Rayet stars of spectral type WC. The power dissipated by the accelerated particles at Orion is about 4 x 10(exp 38) ergs/s. These particles are not expected to produce significant amounts of Al-26.

Ramaty, Reuven; Kozlovsky, Benzion; Lingenfelter, Richard E.

1995-01-01

207

COS Spectra of High-Redshift AGN: Probing Deep into the Rest-Frame Ionizing Continuum and Broad Emission Lines  

NASA Astrophysics Data System (ADS)

The order-of-magnitude improvement in sensitivity of COS over previous spectrographs has increased the number of AGN available for far-UV spectroscopy covering the rest-frame EUV. In archival work, we have enlarged our composite spectrum from 22 to 150 AGN, but the maximum redshift is z_max = 1.47. We request COS/G140L observations of 11 bright AGN {z = 1.45 to 2.13} to extend the composite below 400 A and greatly improve the statistics. At these redshifts, the G140L {1105 A setting} covers 1120-2000 A, probing the rest-frame continuum and emission lines down to 360-450 A. We will observe the Lyman continuum {LyC} below the He I edge {504 A} as it approaches the He II Lya break {304 A}. Obtaining 11 well-exposed QSO spectra will greatly increase our knowledge in the EUV beyond the few AGN currently observed in this band. These LyC photons are responsible for ionizing hydrogen, helium, and many metal ions, for ionizing QSO broad emission-line regions {BELR}, and for heating the IGM. Characterizing the AGN spectrum in the far-UV and ionizing EUV is also a crucial ingredient for studies of accretion disk structure and QSO outflows. We will also measure {or limit} the He I continuum edge {504 A} expected in some models of accretion disks, and will identify and characterize the key QSO broad emission lines in the FUV and EUV {Ne II, Ne III, Ne V, Ne VI, Ne VIII, O II, O III, O IV, O V, O VI}. Detecting multiple ions from the same element {Ne and O} will yield more accurate diagnostics of BELR temperatures and metallicities.

Shull, J.

2013-10-01

208

The Variability of Hardness Ratio 1 observed by ROSAT: Narrow-Line Seyfert 1 Galaxies versus Broad-Line Seyfert 1 Galaxies  

NASA Astrophysics Data System (ADS)

We examined the correlation between the ROSAT Hardness Ratio 1 and Count Rates eight Narrow-line Seyfert 1 Galaxies (NLS1s) and 14 Broad-line Seyfert1 Galaxies (BLS1s). We found that six of the NLS1s show a positive HR1-CTs correlation, and seven of the BLS1s, a negative correlation. The other two NLS1s and seven BLS1s do not show any clear HR1-CTs correlation. Thus, the spectral behavior is statistically different for the NLS1s and BLS1s. The different behaviors can possibly be interpreted in terms of a stable `soft excess' that is strong in NLS1s and weak in BLS1s, plus a power law component, common to both, which softens with increasing flux.

Cheng, Lin-Peng; Wei, Jian-Yan; Zhao, Yong-Heng

2002-06-01

209

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

210

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

SciTech Connect

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

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

2010-08-10

211

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

NASA Astrophysics Data System (ADS)

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

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

2010-08-01

212

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

NASA Technical Reports Server (NTRS)

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

Mushotzky, Richard (Technical Monitor); Risaliti, Guida

2005-01-01

213

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

214

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

215

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

216

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

217

Random Complex Zeroes and Random Nodal Lines  

E-print Network

In these notes, we describe the recent progress in understanding the zero sets of two remarkable Gaussian random functions: the Gaussian entire function with invariant distribution of zeroes with respect to isometries of the complex plane, and Gaussian spherical harmonics on the two-dimensional sphere.

Fedor Nazarov; Mikhail Sodin

2010-03-22

218

DISCOVERY OF THE BROAD-LINED TYPE Ic SN 2013cq ASSOCIATED WITH THE VERY ENERGETIC GRB 130427A  

SciTech Connect

Long-duration gamma-ray bursts (GRBs) at z < 1 are found in most cases to be accompanied by bright, broad-lined Type Ic supernovae (SNe Ic-BL). The highest-energy GRBs are mostly located at higher redshifts, where the associated SNe are hard to detect observationally. Here, we present early and late observations of the optical counterpart of the very energetic GRB 130427A. Despite its moderate redshift, z = 0.3399 ± 0.0002, GRB 130427A is at the high end of the GRB energy distribution, with an isotropic-equivalent energy release of E{sub iso} ? 9.6 × 10{sup 53} erg, more than an order of magnitude more energetic than other GRBs with spectroscopically confirmed SNe. In our dense photometric monitoring, we detect excess flux in the host-subtracted r-band light curve, consistent with that expected from an emerging SN, ?0.2 mag fainter than the prototypical SN 1998bw. A spectrum obtained around the time of the SN peak (16.7 days after the GRB) reveals broad undulations typical of SNe Ic-BL, confirming the presence of an SN, designated SN 2013cq. The spectral shape and early peak time are similar to those of the high expansion velocity SN 2010bh associated with GRB 100316D. Our findings demonstrate that high-energy, long-duration GRBs, commonly detected at high redshift, can also be associated with SNe Ic-BL, pointing to a common progenitor mechanism.

Xu, D.; Krühler, T.; Hjorth, J.; Malesani, D.; Fynbo, J. P. U.; Watson, D. J.; Geier, S. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 København Ø (Denmark); De Ugarte Postigo, A.; Thöne, C. C.; Sánchez-Ramírez, R. [Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía s/n, E-18008 Granada (Spain); Leloudas, G. [The Oskar Klein Centre, Department of Physics, Stockholm University, AlbaNova, SE-10691 Stockholm (Sweden); Cano, Z.; Jakobsson, P. [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, IS-107 Reykjavik (Iceland); Schulze, S. [Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22 (Chile); Kaper, L. [Astronomical Institute Anton Pannekoek, University of Amsterdam, Science Park 904, NL-1098 XH Amsterdam (Netherlands); Sollerman, J. [The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, SE-10691 Stockholm (Sweden); Cabrera-Lavers, A. [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain); Cao, C. [Department of Space Science and Physics, Shandong University at Weihai, Weihai, Shandong 264209 (China); Covino, S. [INAF/Brera Astronomical Observatory, via Bianchi 46, I-23807 Merate (Italy); Flores, H., E-mail: dong@dark-cosmology.dk [Laboratoire Galaxies Etoiles Physique et Instrumentation, Observatoire de Paris, 5 place Jules Janssen, F-92195 Meudon (France); and others

2013-10-20

219

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

220

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

221

The role of radiative acceleration in outflows from broad absorption line QSOs. 1: Comparison with O star winds  

NASA Technical Reports Server (NTRS)

We investigate the role of radiation pressure in accelerating the broad absorption line (BAL) outflows in QSOs by comparing their properties with those of radiatively driven O star winds. We find that, owing to their lower column densities and higher velocity spreads, BAL outflows have only a few tens of strong resonance lines that are dynamically important, as compared with 10(exp 3) - 10(exp 4) lines in O star winds. We show that the combined radiative force (the 'force multiplier') declines more rapidly as a function of column density for BAL outflows than for O star winds. This is mainly attributed to the absence of lines from excited states in the BAL region. The absorbing gas in BAL outflows must have a small filling factor in order for radiative acceleration to be important dynamically. This allows the absorbing material to remain at a high enough density to maintain the ion species necessary for efficient radiative acceleration as well (as those responsible for the observed absorption), without the average flow density becoming so large that the absorbing matter cannot be accelerated by an increment larger than its own sound speed. The latter condition is necessary if the outflow is to tap a large portion of the incident photon momentum. Once a small filling factor is assumed, radiative acceleration can be more efficient in BAL outflows than in O stars. We show that terminal velocities of a few times 10(exp 4) km/sec can be expected, provided that the absorbing matter does not have to drag with it a much heavier substrate.

Arav, Nahum; Li, Zhi-Yun

1994-01-01

222

Mon. Not. R. Astron. Soc. 383, 14851500 (2008) doi:10.1111/j.1365-2966.2007.12647.x The broad-lined Type Ic supernova 2003jd  

E-print Network

-lined Type Ic supernova 2003jd S. Valenti,1,2 S. Benetti,3 E. Cappellaro,3 F. Patat,2 P. Mazzali,4,5 M The results of a worldwide coordinated observational campaign on the broad-lined Type Ic supernova (SN Ic different telescopes. SN 2003jd is one of the most luminous SN Ic ever observed. A comparison with other

California at Berkeley, University of

223

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

224

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.

225

Discovery of an Obscured Broad Line Region in the High Redshift Radio Galaxy MRC 2025-218  

E-print Network

This paper presents infrared spectra taken with the newly commissionedNIRSPEC spectrograph on the Keck II Telescope of the High Redshift Radio GalaxyMRC 2025-218 (z=2.63) These observations represent the deepest infrared spectraof a radio galaxy to date and have allowed for the detection of Hbeta, [OIII](4959/5007), [OI] (6300), Halpha, [NII] (6548/6583) and [SII] (6716/6713). TheHalpha emission is very broad (FWHM = 9300 km/s) and luminous (2.6x10^44ergs/s) and it is very comparable to the line widths and strengths of radioloud quasars at the same redshift. This strongly supports AGN unificationmodels linking radio galaxies and quasars, although we discuss some of theoutstanding differences. The [OIII] (5007) line is extremely strong and hasextended emission with large relative velocities to the nucleus. We also derivethat if the extended emission is due to star formation, each knot has a starformation rate comparable to a Lyman Break Galaxy at the same redshift.

Larkin, J E; Graham, J R; Becklin, E E; Figer, D F; Gilbert, A M; Levenson, N A; Teplitz, H I; Wilcox, M K; Glassman, T M; Larkin, James E.; Lean, Ian S. Mc; Graham, James R.; Figer, Donald F.; Gilbert, Andrea M.; Teplitz, Harry I.; Wilcox, Mavourneen K.; Glassman, Tiffany M.

2000-01-01

226

Discovery of an Obscured Broad Line Region in the High Redshift Radio Galaxy MRC 2025-218  

E-print Network

This paper presents infrared spectra taken with the newly commissioned NIRSPEC spectrograph on the Keck II Telescope of the High Redshift Radio Galaxy MRC 2025-218 (z=2.63) These observations represent the deepest infrared spectra of a radio galaxy to date and have allowed for the detection of Hbeta, [OIII] (4959/5007), [OI] (6300), Halpha, [NII] (6548/6583) and [SII] (6716/6713). The Halpha emission is very broad (FWHM = 9300 km/s) and luminous (2.6x10^44 ergs/s) and it is very comparable to the line widths and strengths of radio loud quasars at the same redshift. This strongly supports AGN unification models linking radio galaxies and quasars, although we discuss some of the outstanding differences. The [OIII] (5007) line is extremely strong and has extended emission with large relative velocities to the nucleus. We also derive that if the extended emission is due to star formation, each knot has a star formation rate comparable to a Lyman Break Galaxy at the same redshift.

James E. Larkin; Ian S. McLean; James R. Graham; E. E. Becklin; Donald F. Figer; Andrea M. Gilbert; N. A. Levenson; Harry I. Teplitz; Mavourneen K. Wilcox; Tiffany M. Glassman

2000-02-17

227

The FIRST Radio-Loud Broad Absorption Line QSO and Evidence for a Hidden Population of Quasars  

E-print Network

We have discovered two low-ionization broad absorption line quasars in programs to obtain optical spectra for radio-selected quasar candidates from the VLA FIRST Survey (Becker, White, & Helfand 1995). Both belong to the extremely rare class of BAL QSOs that exhibit narrow absorption lines from metastable excited levels of Fe II and Fe III. Until now, there was just a single object in this class, 0059-2735 (Hazard et al. 1987). In addition, one of our new objects is the first known radio-loud BAL QSO. The properties of these three unusual objects suggest a trend of increasing radio luminosity with the amount of absorption to the quasar, and are perhaps transition objects between radio-loud and radio-quiet quasars. The two new objects are from a radio-selected sample comprising less than 200 quasars; one is heavily attenuated at optical wavelengths in the observed frame. These objects would be easily overlooked by most optical QSO searches; their abundance in the radio sample suggests that they may be representatives of a largely undetected component of the quasar population, perhaps as numerous as ordinary low-ionization BAL QSOs which constitute 1-2% of all QSOs.

Robert H. Becker; Michael D. Gregg; Isobel M. Hook; Richard G. McMahon; Richard L. White; David J. Helfand

1997-01-31

228

Hard X-Ray Spectra of Broad-Line Radio Galaxies from the Rossi X-Ray Timing Explorer  

NASA Astrophysics Data System (ADS)

We present the results of hard X-ray observations of four broad-line radio galaxies (BLRGs) with the Rossi X-Ray Timing Explorer. The original motivation behind the observations was to search for systematic differences between the BLRGs and their radio-quiet counterparts, the Seyfert galaxies. We do, indeed, find that the Fe K? lines and Compton ``reflection'' components, which are hallmarks of the X-ray spectra of Seyfert galaxies, are weaker in BLRGs by about a factor of 2. This observational result is in agreement with the conclusions of other recent studies of these objects. We examine several possible explanations for this systematic difference, including beaming of the primary X-rays away from the accretion disk, a low iron abundance, a small solid angle subtended by the disk to the primary X-ray source, and dilution of the observed spectrum by beamed X-rays from the jet. We find that a small solid angle subtended by the disk to the primary X-ray source is a viable and appealing explanation, while all others suffer from drawbacks. We interpret this as an indication of a difference in the inner accretion disk structure between Seyfert galaxies and BLRGs, namely that the inner accretion disks of BLRGs have the form of an ion-supported torus or an advection-dominated accretion flow, which irradiates the geometrically thin outer disk.

Eracleous, Michael; Sambruna, Rita; Mushotzky, Richard F.

2000-07-01

229

Discovery of an Obscured Broad-Line Region in the High-Redshift Radio Galaxy MRC 2025-218.  

PubMed

This Letter presents infrared spectra taken with the newly commissioned near-infrared spectrometer (NIRSPEC) on the Keck II telescope of the high-redshift radio galaxy MRC 2025-218 (z=2.63). These observations represent the deepest infrared spectra of a radio galaxy to date and have allowed for the detection of Hbeta, [O iii] lambdalambda4959, 5007, [O i] lambda6300, Halpha, [N ii] lambdalambda6548, 6583, and [S ii] lambdalambda6716, 6713. The Halpha emission is very broad (FWHM=9300 km s-1) and luminous (2.6x1044 ergs s-1), and it is very comparable to the line widths and strengths of radio-loud quasars at the same redshift. This strongly supports active galactic nucleus unification models linking radio galaxies and quasars, although we discuss some of the outstanding differences. The line [O iii] lambda5007 is extremely strong and has extended emission with large relative velocities toward the nucleus. We also derive that if the extended emission is due to star formation, each knot has a star formation rate comparable to a Lyman-break galaxy at the same redshift. PMID:10727392

Larkin; McLean; Graham; Becklin; Figer; Gilbert; Levenson; Teplitz; Wilcox; Glassman

2000-04-10

230

A Comparison of Hard X-ray Photon Indices and Iron K' Emission Lines in X-ray Luminous Narrow- and Broad-line Seyfert 1 Galaxies  

NASA Astrophysics Data System (ADS)

We use publicly available XMM-Newton data to systematically compare the hard X-ray photon indices, ˜2-10 keV, and the iron K' emission lines of narrow- and broad-line Seyfert 1 (NLS1 and BLS1) galaxies. We compile a flux-limited (f 2-10 keV >= 1 × 10^{-12} erg s^{-1} cm^{-2}) sample including 114 radio-quiet objects, with the 2-10 keV luminosity ranging from 1041 to 1045 erg s^{-1}. Our main results are: (1) NLS1s and BLS1s show similar luminosity distributions; (2) the weighted means of ˜2-10 keV of NLS1s, BLS1s, and the total sample are 2.04 ± 0.04, 1.74 ± 0.02, and 1.84 ± 0.02, respectively; a significant anti-correlation between ˜2-10 keV and FWHM H?suggests that ˜2-10 keV > 2.0 may be taken to indicate the X-ray luminous NLS1 type; (3) the 6.4 keV narrow iron K' lines from NLS1s are generally weaker than that from BLS1s; this would indicate a smaller covering factor of the dusty tori in NLS1s if the line emission originates from the inner boundary region of the dusty torus in an active galactic nucleus; and (4) all the broadened iron K' lines with intrinsic width œÉ>0.5 keV correspond to FWHM H? <=4000 km s^{-1}.

Zhou, XinLin

2012-09-01

231

A Comparison of Hard X-ray Photon Indices and Iron K? Emission Lines in X-ray Luminous Narrow- and Broad-line Seyfert 1 Galaxies  

NASA Astrophysics Data System (ADS)

We use publicly available XMM-Newton data to systematically compare the hard X-ray photon indices, ?2-10 keV , and the iron K? emission lines of narrow- and broad-line Seyfert 1 (NLS1 and BLS1) galaxies. We compile a flux-limited (f 2-10 keV >= 1 × 10-12 erg s-1 cm-2) sample including 114 radio-quiet objects, with the 2-10 keV luminosity ranging from 1041 to 1045 erg s-1. Our main results are: (1) NLS1s and BLS1s show similar luminosity distributions; (2) the weighted means of ?2-10 keV of NLS1s, BLS1s, and the total sample are 2.04 ± 0.04, 1.74 ± 0.02, and 1.84 ± 0.02, respectively; a significant anti-correlation between ?2-10 keV and FWHMH? suggests that ?2-10 keV > 2.0 may be taken to indicate the X-ray luminous NLS1 type; (3) the 6.4 keV narrow iron K? lines from NLS1s are generally weaker than that from BLS1s; this would indicate a smaller covering factor of the dusty tori in NLS1s if the line emission originates from the inner boundary region of the dusty torus in an active galactic nucleus; and (4) all the broadened iron K? lines with intrinsic width ?>0.5 keV correspond to FWHMH? <=4000 km s-1.

Zhou, Xin-Lin; Zhang, Shuang-Nan

2010-04-01

232

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

SciTech Connect

1991 was continued rapid growth for the Santa Fe Institute (SFI) as it broadened its interdisciplinary research into the organization, evolution and operation of complex systems and sought deeply the principles underlying their dynamic behavior. Research on complex systems--the focus of work at SFI--involves an extraordinary range of topics normally studied in seemingly disparate fields. Natural systems displaying complex behavior range upwards from proteins and DNA through cells and evolutionary systems to human societies. Research models exhibiting complexity include nonlinear equations, spin glasses, cellular automata, genetic algorithms, classifier systems, and an array of other computational models. Some of the major questions facing complex systems researchers are: (1) explaining how complexity arises from the nonlinear interaction of simples components, (2) describing the mechanisms underlying high-level aggregate behavior of complex systems (such as the overt behavior of an organism, the flow of energy in an ecology, the GNP of an economy), and (3) creating a theoretical framework to enable predictions about the likely behavior of such systems in various conditions. The importance of understanding such systems in enormous: many of the most serious challenges facing humanity--e.g., environmental sustainability, economic stability, the control of disease--as well as many of the hardest scientific questions--e.g., protein folding, the distinction between self and non-self in the immune system, the nature of intelligence, the origin of life--require deep understanding of complex systems.

Not Available

1991-12-31

233

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

SciTech Connect

1991 was continued rapid growth for the Santa Fe Institute (SFI) as it broadened its interdisciplinary research into the organization, evolution and operation of complex systems and sought deeply the principles underlying their dynamic behavior. Research on complex systems--the focus of work at SFI--involves an extraordinary range of topics normally studied in seemingly disparate fields. Natural systems displaying complex behavior range upwards from proteins and DNA through cells and evolutionary systems to human societies. Research models exhibiting complexity include nonlinear equations, spin glasses, cellular automata, genetic algorithms, classifier systems, and an array of other computational models. Some of the major questions facing complex systems researchers are: (1) explaining how complexity arises from the nonlinear interaction of simples components, (2) describing the mechanisms underlying high-level aggregate behavior of complex systems (such as the overt behavior of an organism, the flow of energy in an ecology, the GNP of an economy), and (3) creating a theoretical framework to enable predictions about the likely behavior of such systems in various conditions. The importance of understanding such systems in enormous: many of the most serious challenges facing humanity--e.g., environmental sustainability, economic stability, the control of disease--as well as many of the hardest scientific questions--e.g., protein folding, the distinction between self and non-self in the immune system, the nature of intelligence, the origin of life--require deep understanding of complex systems.

Not Available

1991-01-01

234

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

235

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

236

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

237

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

SciTech Connect

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

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

2012-09-10

238

A Comprehensive Study of Broad Absorption Line Quasars. I. Prevalence of HeI* Absorption Line Multiplets in Low-ionization Objects  

NASA Astrophysics Data System (ADS)

Neutral helium multiplets, He i* ? ? 3189,3889,10830, are very useful diagnostics for the geometry and physical conditions of the absorbing gas in quasars. So far only a handful of He i* detections have been reported. Using a newly developed method, we detected the He i*? 3889 absorption line in 101 sources of a well-defined sample of 285 Mg ii broad absorption line (BAL) quasars selected from SDSS DR5. This has increased the number of He i* BAL quasars by more than one order of magnitude. We further detected He i*? 3189 in 50% (52/101) of the quasars in the sample. The detection fraction of He i* BALs in Mg ii BAL quasars is ?35% as a whole, and it increases dramatically with increasing spectral signal-to-noise ratio (S/N), from ?18% at S/N ?slant 10 to ?93% at S/N ?slant 35. This suggests that He i* BALs could be detected in most Mg ii LoBAL quasars, provided the spectra S/N is high enough. Such a surprisingly high He i* BAL fraction is actually predicted from photoionization calculations based on a simple BAL model. The result indicates that He i* absorption lines can be used to search for BAL quasars at low z, which cannot be identified by ground-based optical spectroscopic surveys with commonly seen UV absorption lines. Using He i* ?3889, we discovered 19 BAL quasars at z\\lt 0.3 from the available SDSS spectral database. The fraction of He i* BAL quasars is similar to that of LoBAL objects.

Liu, Wen-Juan; Zhou, Hongyan; Ji, Tuo; Yuan, Weimin; Wang, Ting-Gui; Jian, Ge; Shi, Xiheng; Zhang, Shaohua; Jiang, Peng; Shu, Xinwen; Wang, Huiyuan; Wang, Shu-Fen; Sun, Luming; Yang, Chenwei; Liu, Bo; Zhao, Wen

2015-03-01

239

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

240

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

SciTech Connect

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

Not Available

1988-12-20

241

Crosslinked HIV-1 envelope–CD4 receptor complexes elicit broadly cross-reactive neutralizing antibodies in rhesus macaques  

PubMed Central

The identification of HIV envelope structures that generate broadly cross-reactive neutralizing antibodies is a major goal for HIV-vaccine development. In this study, we evaluated one such structure, expressed as either a gp120–CD4 or a gp140–CD4 complex, for its ability to elicit a neutralizing antibody response. In rhesus macaques, covalently crosslinked complexes of soluble human CD4 (shCD4) and HIV-1IIIB envelope glycoproteins (gp120 or gp140) generated antibodies that neutralized a wide range of primary HIV-1 isolates regardless of the coreceptor usage or genetic subtype. Ig with cross-reactive neutralizing activity was recovered by affinity chromatography with a chimeric single-chain polypeptide containing sequences for HIVBaL gp120 and a mimetic peptide that induces a CD4-triggered envelope structure. These results suggest that covalently crosslinked complexes of the HIV-1 surface envelope glycoprotein and CD4 elicit broadly neutralizing humoral responses that, in part, may be directed against a novel epitope(s) found on the HIV-1 envelope. PMID:12192089

Fouts, Timothy; Godfrey, Karla; Bobb, Kathryn; Montefiori, David; Hanson, Carl V.; Kalyanaraman, V. S.; DeVico, Anthony; Pal, Ranajit

2002-01-01

242

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

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

243

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

244

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

245

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

SciTech Connect

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

NONE

1993-12-31

246

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

PubMed Central

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

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

2013-01-01

247

The Black Hole Fundamental Plane from a Uniform Sample of Radio and X-Ray-emitting Broad-Line AGNs  

NASA Astrophysics Data System (ADS)

We derived the black hole fundamental plane relationship between the 1.4 GHz radio luminosity (Lr), 0.1-2.4 keV X-ray luminosity (LX), and black hole mass (M) from a uniform broad-line SDSS AGN sample including both radio-loud and radio-quiet X-ray-emitting sources. We found in our sample that the fundamental plane relation has a very weak dependence on the black hole mass, and a tight correlation also exists between the Eddington-luminosity-scaled X-ray and radio luminosities for the radio-quiet subsample. In addition, we noticed that the radio-quiet and radio-loud AGNs have different power-law slopes in the radio-X-ray nonlinear relationship. The radio-loud sample displays a slope of 1.39, which seems consistent with the jet-dominated X-ray model. However, it may also be partly due to the relativistic beaming effect. For the radio-quiet sample the slope of the radio-X-ray relationship is about 0.85, which is possibly consistent with the theoretical prediction from the accretion-flow-dominated X-ray model. We briefly discuss the reason why our derived relationship is different from some previous works and expect the future spectral studies in radio and X-ray bands on individual sources in our sample to confirm our result.

Wang, Ran; Wu, Xue-Bing; Kong, Min-Zhi

2006-07-01

248

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

NASA Astrophysics Data System (ADS)

We investigate orbital motion of spherical, pressure-confined clouds in the broad-line region (BLR) of active galactic nuclei (AGNs). 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 as the pressure distribution of the intercloud medium decreases from the equator to the pole.

Khajenabi, Fazeleh

2015-01-01

249

Interaction between the Broad-lined Type Ic Supernova 2012ap and Carriers of Diffuse Interstellar Bands  

NASA Astrophysics Data System (ADS)

Diffuse interstellar bands (DIBs) are absorption features observed in optical and near-infrared spectra that are thought to be associated with carbon-rich polyatomic molecules in interstellar gas. However, because the central wavelengths of these bands do not correspond to electronic transitions of any known atomic or molecular species, their nature has remained uncertain since their discovery almost a century ago. Here we report on unusually strong DIBs in optical spectra of the broad-lined Type Ic supernova SN 2012ap that exhibit changes in equivalent width over short (lsim 30 days) timescales. The 4428 Å and 6283 Å DIB features get weaker with time, whereas the 5780 Å feature shows a marginal increase. These nonuniform changes suggest that the supernova is interacting with a nearby source of DIBs and that the DIB carriers possess high ionization potentials, such as small cations or charged fullerenes. We conclude that moderate-resolution spectra of supernovae with DIB absorptions obtained within weeks of outburst could reveal unique information about the mass-loss environment of their progenitor systems and provide new constraints on the properties of DIB carriers.

Milisavljevic, Dan; Margutti, Raffaella; Crabtree, Kyle N.; Foster, Jonathan B.; Soderberg, Alicia M.; Fesen, Robert A.; Parrent, Jerod T.; Sanders, Nathan E.; Drout, Maria R.; Kamble, Atish; Chakraborti, Sayan; Pickering, Timothy E.; Cenko, S. Bradley; Silverman, Jeffrey M.; Filippenko, Alexei V.; Kirshner, Robert P.; Mazzali, Paolo; Maeda, Keiichi; Marion, G. H. Howie; Vinko, Jozsef; Wheeler, J. Craig

2014-02-01

250

Value and limitations of adenosine in the diagnosis and treatment of narrow and broad complex tachycardias  

Microsoft Academic Search

The diagnostic and therapeutic potential of intravenous adenosine was studied in 64 patients during 92 episodes of regular sustained tachycardia. In 40 patients who had narrow complex tachycardias (QRS less than 0.12 s) adenosine (2.5-25 mg) restored sinus rhythm in 25 with junctional tachycardias (46 of 48 episodes) and produced atrioventricular block to reveal atrial or sinus tachycardia in 15.

A C Rankin; K G Oldroyd; E Chong; A P Rae; S M Cobbe

1989-01-01

251

Design Methodology of Long Complex Helium Cryogenic Transfer Lines  

NASA Astrophysics Data System (ADS)

Big scientific facilities, like superconducting particle accelerators or fusion reactors require high cooling power, usually produced locally by large helium refrigerators and transferred, by means of liquid or supercritical helium, over the distances that may exceed several kilometres. Construction of cold helium transfer lines should take into consideration many different issues. The lines are exposed to thermal loads which can constitute an important part of the cryogenic system thermal budget. Pressure difference between the vacuum insulation and the inner content of the pipes causes significant mechanical stresses. The cyclic changes of temperature can lead to considerable fatigue stresses. Additionally, due to complex structure of the scientific facilities, the access to the cryogenic lines can be partly or totally limited. Therefore all these thermal and mechanical aspects have to be analyzed and compromised during the design phase of the complex helium transfer line. The paper presents a design methodology of long multi-channel helium cryogenic transfer lines. It describes some aspects of process line arrangement, thermo-mechanical calculation, supporting structure and contraction protection, taking as a case study cryogenic transfer line XATL1, dedicated for the Accelerator Module Test Facility (AMTF) of the European X-rays Free Electron Laser (XFEL).

Fydrych, J.; Chorowski, M.; Polinski, J.; Skrzypacz, J.

2010-04-01

252

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

SciTech Connect

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

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

1994-11-01

253

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

254

Differential interferometry of QSO broad-line regions - I. Improving the reverberation mapping model fits and black hole mass estimates  

NASA Astrophysics Data System (ADS)

Reverberation mapping (RM) estimates the size and kinematics of broad-line regions (BLR) in quasars and type I AGNs. It yields size-luminosity relation to make QSOs standard cosmological candles, and mass-luminosity relation to study the evolution of black holes and galaxies. The accuracy of these relations is limited by the unknown geometry of the BLR clouds distribution and velocities. We analyse the independent BLR structure constraints given by super-resolving differential interferometry. We developed a three-dimensional BLR model to compute all differential interferometry and RM signals. We extrapolate realistic noises from our successful observations of the QSO 3C 273 with AMBER on the VLTI. These signals and noises quantify the differential interferometry capacity to discriminate and measure BLR parameters including angular size, thickness, spatial distribution of clouds, local-to-global and radial-to-rotation velocity ratios, and finally central black hole mass and BLR distance. A Markov Chain Monte Carlo model-fit, of data simulated for various VLTI instruments, gives mass accuracies between 0.06 and 0.13 dex, to be compared to 0.44 dex for RM mass-luminosity fits. We evaluate the number of QSOs accessible to observe with current (AMBER), upcoming (GRAVITY) and possible (OASIS with new generation fringe trackers) VLTI instruments. With available technology, the VLTI could resolve more than 60 BLRs, with a luminosity range larger than four decades, sufficient for a good calibration of RM mass-luminosity laws, from an analysis of the variation of BLR parameters with luminosity.

Rakshit, Suvendu; Petrov, Romain G.; Meilland, Anthony; Hönig, Sebastian F.

2015-03-01

255

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

256

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 significantly weaker reflection features. One possible 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 seperated 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 ?=1.68+0.03-0.02, while the photon-index of the higher flux spectrum is ?=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=228± 19 keV in the low flux data to 158+35-76 keV in the high flux observation (assuming a slab geometry). These are precisely the characteristics of a Comptonizing corona, and are distinct from those found in jet-dominated sources. 3C 382 exhibits very weak reflection features, which may be best explained by an outflowing corona combined with an ionized inner accretion disk.

Ballantyne, David R.; Bollenbacher, John; Brenneman, Laura; Madsen, Kristin; Balokovic, Mislav; Boggs, Steven E.; Christensen, Finn; Craig, William W.; Gandhi, Poshak; Hailey, Charles James; Harrison, Fiona; Lohfink, Anne M.; Marinucci, Andrea; Markwardt, Craig; Stern, Daniel; Walton, Dom; Zhang, William

2014-08-01

257

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

258

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

259

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

260

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

PubMed

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

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

2013-12-01

261

A CHANDRA SURVEY OF THE X-RAY PROPERTIES OF BROAD ABSORPTION LINE RADIO-LOUD QUASARS  

SciTech Connect

This work presents the results of a Chandra study of 21 broad absorption line (BAL) radio-loud quasars (RLQs). We conducted a Chandra snapshot survey of 12 bright BAL RLQs selected from Sloan Digital Sky Survey Data/Faint Images of the Radio Sky data and possessing a wide range of radio and C IV absorption properties. Optical spectra were obtained nearly contemporaneously with the Hobby-Eberly Telescope; no strong flux or BAL variability was seen between epochs. In addition to the snapshot targets, we include in our sample nine additional BAL RLQs possessing archival Chandra coverage. We compare the properties of (predominantly high-ionization) BAL RLQs to those of non-BAL RLQs as well as to BAL radio-quiet quasars (RQQs) and non-BAL RQQs for context. All 12 snapshots and 8/9 archival BAL RLQs are detected, with observed X-ray luminosities less than those of non-BAL RLQs having comparable optical/UV luminosities by typical factors of 4.1-8.5. (BAL RLQs are also X-ray weak by typical factors of 2.0-4.5 relative to non-BAL RLQs having both comparable optical/UV and radio luminosities.) However, BAL RLQs are not as X-ray weak relative to non-BAL RLQs as are BAL RQQs relative to non-BAL RQQs. While some BAL RLQs have harder X-ray spectra than typical non-BAL RLQs, some have hardness ratios consistent with those of non-BAL RLQs, and there does not appear to be a correlation between X-ray weakness and spectral hardness, in contrast to the situation for BAL RQQs. RLQs are expected to have X-ray continuum contributions from both accretion-disk corona and small-scale jet emission. While the entire X-ray continuum in BAL RLQs cannot be obscured to the same degree as in BAL RQQs, we calculate that the jet is likely partially covered in many BAL RLQs. We comment briefly on implications for geometries and source ages in BAL RLQs.

Miller, B. P.; Brandt, W. N.; Garmire, G. P. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Gibson, R. R. [Department of Astronomy, University of Washington, Physics-Astronomy Bldg Room C319, Seattle, WA 98195 (United States); Shemmer, O. [Department of Physics, University of North Texas, 1155 Union Circle, 311427, Denton, TX 76203 (United States)], E-mail: bmiller@astro.psu.edu, E-mail: niel@astro.psu.edu, E-mail: garmire@astro.psu.edu, E-mail: rgibson@astro.washington.edu, E-mail: ohad@unt.edu

2009-09-10

262

Hubble Space Telescope Observations of the Gravitationally Lensed Cloverleaf Broad Absorption Line QSO H1413+1143: Imaging  

NASA Astrophysics Data System (ADS)

An analysis of Hubble Space Telescope (HST) Wide Field Planetary Camera (WFPC) and Wide Field Planetary Camera 2 (WFPC2) images of the gravitationally lensed Cloverleaf broad absorption line quasi-stellar object (QSO) H1413+1143 is presented. Astrometric and photometric measurements are derived for the four components of the lensed QSO for five different epochs over a baseline of 2.76 yr. Because of the replacement of WFPC with WFPC2 and the change in the purpose of the observation at the various epochs, the data were not always taken with the same filter. With the exception of the declination of component D, the relative positions of the four components are measured to within ~3 mas; these results are consistent with but considerably more accurate than earlier measurements. The relative photometric measurements at any one epoch are typically accurate to ~0.02-0.03 mag (1 ?). The initial HST WFPC images cover a baseline of 1.26 yr (1992.21-1993.47 [1992 March 16-1993 June 22]), and over this time interval there is little evidence for brightness variations of any of the components relative to one another at levels >0.06 mag (>2 ?). Photometric measurements of the more accurate WFPC2 data obtained with different filters extends this baseline an additional 1.50 yr (to 1994.97 [1994 December 22]). The WFPC2 data also fail to reveal significant brightness variations among the components. In addition, the WFPC2 data include both UV (F336W) and near-infrared (F814W) images. These color data indicate the presence of sight-line-dependent extinction, causing the F336W-F814W color index of component B (the most reddened component) to be 0.56 +/- 0.04 mag redder than that of component C (the least reddened component). The lack of evidence for significant component brightness variations at all HST observation epochs suggests that the data could be reliably extinction-corrected to derive the relative amplifications of the four image components. This is done for several reasonable dust-extinction models. Thus, the derived astrometry along with the photometric analysis set clear constraints on models for the Cloverleaf. Since component D shows some evidence for microlensing, the results on its relative amplification should be used with caution. While existing models can successfully reproduce the relative positions, the relative amplifications have not yet been successfully modeled. The WFPC2 imaging data has also permitted a sensitive search for component structure and the gravitational lens itself. There is marginal evidence for elongated structure between components A and C that may be part of an Einstein ring. However, no significant evidence for the lensing object is found. The various measurements are quantified in ways useful for setting model constraints. Limits on the mass-to-light ratio and detectability of the lensing galaxy are also discussed. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.

Turnshek, David A.; Lupie, Olivia L.; Rao, Sandhya M.; Espey, Brian R.; Sirola, Christopher J.

1997-08-01

263

The Hard X-Ray Spectra of Broad-Line Radio Galaxies as Observed With the Rossi X-Ray Timing Explorer  

NASA Astrophysics Data System (ADS)

We present the hard X-ray spectra of a sample of four broad-line radio galaxies observed with the Rossi X-Ray Timing Explorer, namely 3C 111, Pictor A, 3C 120, and 3C 382. The spectra are described by a power-law model with spectral indices in the range 1.6 to 1.8, which are lower than the typical values found in Seyfert galaxies. In the case of Pictor A and 3C 111 we detect weak Fe Kalpha emission lines (EW<=100 eV) which were not detected in earlier spectra obtained with ASCA. We also find that the power-law model provides a good description of the spectra up to high energies (20--30 keV). The Compton reflection hump, which is a hallmark of the X-ray spectra of Seyfert galaxies at these energies is either weak or undetectable in the broad-line radio galaxies of our small sample, with interesting upper limits. We argue that a plausible explanation for this observational result is a difference between the structure of the inner accretion disks of Seyfert galaxies and broad-line radio galaxies. This work was supported by NASA through grant NAG5-7733.

Eracleous, M.; Sambruna, R. M.; Mushotzky, R. F.

1999-05-01

264

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

SciTech Connect

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

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

2010-05-20

265

HST observations of NGC 4395, the least luminous Seyfert 1 nucleus - Evidence against the starburst hypothesis for broad-lined active galactic nuclei  

NASA Technical Reports Server (NTRS)

The starburst hypothesis for broad-line AGN is examined here using ultraviolet spectra and optical images of NGC 4395, the least luminous Seyfert 1 nucleus. From the evidence it is concluded that the apparent activity in the Seyfert 1 nucleus of NGC 4395 probably cannot be explained in the context of the starburst hypothesis of Terlevich et al. (1992). The strongest piece of evidence is the absence of stellar absorption lines, especially in the UV and NIR spectra. Other relevant characteristics are the UV spectral index of roughly -1, small physical size, low luminosity, and lack of obvious variability.

Filippenko, Alexei V.; Ho, Luis C.; Sargent, Wallace L. W.

1993-01-01

266

BeppoSAX observations of 2-Jy lobe-dominated broad-line sources - I. The discovery of a hard X-ray component  

NASA Astrophysics Data System (ADS)

We present new BeppoSAX LECS, MECS and PDS observations of five lobe-dominated, broad-line active galactic nuclei selected from the 2-Jy sample of southern radio sources. These include three radio quasars and two broad-line radio galaxies. ROSAT PSPC data, available for all the objects, are also used to constrain the spectral shape better in the soft X-ray band. The collected data cover the energy range 0.1 - 10 keV, reaching ~ 50 keV for one source (Pictor A). The main result from the spectral fits is that all sources have a hard X-ray spectrum with energy index alpha_x ~ 0.75 in the 2 - 10 keV range. This is at variance with the situation at lower energies where these sources exhibit steeper spectra. Spectral breaks Delta alpha_x ~ 0.5 at 1 - 2 keV characterize in fact the overall X-ray spectra of our objects. The flat, high-energy slope is very similar to that displayed by flat-spectrum/core-dominated quasars, which suggests that the same emission mechanism (most likely inverse Compton) produces the hard X-ray spectra in both classes. Finally, a (weak) thermal component is also present at low energies in the two broad-line radio galaxies included in our study.

Padovani, Paolo; Morganti, Raffaella; Siebert, Joachim; Vagnetti, Fausto; Cimatti, Andrea

1999-04-01

267

BeppoSAX observations of 2 Jy lobe-dominated broad-line sources: the discovery of a hard X-ray component  

NASA Astrophysics Data System (ADS)

We present new BeppoSAX LECS, MECS, and PDS observations of five lobe-dominated, broad-line active galactic nuclei selected from the 2 Jy sample of southern radio sources. These include three radio quasars and two broad-line radio galaxies. ROSAT PSPC data, available for all the objects, are also used to better constrain the spectral shape in the soft X-ray band. The collected data cover the 0.1-10keV energy range, reaching 40keV for one source. Detailed spectral fitting shows that all sources have a flat hard X-ray spectrum with energy index ?x~0.75 in the 2-10keV energy range. This is a new result, which is at variance with the situation at lower energies where these sources exhibit steeper spectra. Spectral breaks ~0.5 at 1-2keV characterize the overall X-ray spectra of our objects. The flat, high-energy slope is very similar to that displayed by flat-spectrum/core-dominated quasars, which suggests that the same emission mechanism (most likely inverse Compton) produces the hard X-ray spectra in both classes. Contrary to the optical evidence for some of our sources, no absorption above the Galactic value is found in our sample. Finally, a (weak) thermal component is also present at low energies in the two broad-line radio galaxies included in our study.

Morganti, Raffaella; Padovani, Paolo; Siebert, Joachim; Cimatti, Andrea; Tadhunter, Clive N.; Vagnetti, Fausto

1999-01-01

268

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

269

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

270

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

271

Spectrophotometry and Imaging of the Lensed, Clover Leaf Broad Absorption Line QSO 1413+117-PART II-Cyc 4 High-Spectra  

NASA Astrophysics Data System (ADS)

Observations of the gravitationally lensed "Cloverleaf" Broad Absorption Line (BAL) QSO Q1413+117 are a follow-on to a Cycle 1 proposal. Red and blue WFPC2 images and FOS spectra will be taken to achieve the following aims: (1) The red WFPC2 PC images, taken earlier in 1994, were used as EARLY ACQs and searched for other component images and the lensing galaxy. Note that the lensing was not discovered and so must be fainter than models suggest. (2) FOS data on the QSO image components will be used to check sight-line dependent differences in BAL profiles. The results can be used to place constraints on BAL region cloud sizes and shapes. WFPC2 Red (f814w) and blue(f336w) images will replace (11/94) the FOS galaxy spectrum in grating 650L. These images will yield sight-line dependent differences in dust extinction.

Turnshek, David

1994-01-01

272

Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XV. Long-Term Optical Monitoring of NGC 5548  

E-print Network

We present the results of three years of ground-based observations of the Seyfert 1 galaxy NGC 5548, which combined with previously reported data, yield optical continuum and broad-line H-beta light curves for a total of eight years. The light curves consist of over 800 points, with a typical spacing of a few days between observations. During this eight-year period, the nuclear continuum has varied by more than a factor of seven, and the H-beta emission line has varied by a factor of nearly six. The H-beta emission line responds to continuum variations with a time delay or lag of 10-20 days, the precise value varying somewhat from year to year. We find some indications that the lag varies with continuum flux in the sense that the lag is larger when the source is brighter.

B. M. Peterson; A. J. Barth; P. Berlind; R. Bertram; K. Bischoff; N. G. Bochkarev; A. N. Burenkov; F. -Z. Cheng; M. Dietrich; A. V. Filippenko; E. Giannuzzo; L. C. Ho; J. P. Huchra; J. Hunley; S. Kaspi; W. Kollatschny; D. C. Leonard; Yu. F. Malkov; T. Matheson; M. Mignoli; B. Nelson; P. Papaderos; J. Peters; R. W. Pogge; V. I. Pronik; S. G. Sergeev; E. A. Sergeeva; A. I. Shapovalova; G. M. Stirpe; S. Tokarz; R. M. Wagner; I. Wanders; J. -Y. Wei; B. J. Wilkes; H. Wu; S. -J. Xue; Z. -L. Zou

1998-08-21

273

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

274

Unshifted Metastable He I* Mini-broad Absorption Line System in the Narrow-line Type 1 Quasar SDSS J080248.18+551328.9  

NASA Astrophysics Data System (ADS)

We report the identification of an unusual absorption-line system in the quasar SDSS J080248.18+551328.9 and present a detailed study of the system, incorporating follow-up optical and near-IR spectroscopy. A few tens of absorption lines are detected, including He I*, Fe II*, and Ni II*, which arise from metastable or excited levels, as well as resonant lines in Mg I, Mg II, Fe II, Mn II, and Ca II. All of the isolated absorption lines show the same profile of width ?v ~ 1500 km s–1 centered at a common redshift as that of the quasar emission lines, such as [O II], [S II], and hydrogen Paschen and Balmer series. With narrow Balmer lines, strong optical Fe II multiplets, and weak [O III] doublets, its emission-line spectrum is typical for that of a narrow-line Seyfert 1 galaxy (NLS1). We have derived reliable measurements of the gas-phase column densities of the absorbing ions/levels. Photoionization modeling indicates that the absorber has a density of n H ~ (1.0-2.5) × 105 cm–3 and a column density of N H ~ (1.0-3.2) × 1021 cm–2 and is located at R ~100-250 pc from the central supermassive black hole. The location of the absorber, the symmetric profile of the absorption lines, and the coincidence of the absorption- and emission-line centroid jointly suggest that the absorption gas originates from the host galaxy and is plausibly accelerated by stellar processes, such as stellar winds and/or supernova explosions. The implications for the detection of such a peculiar absorption-line system in an NLS1 are discussed in the context of coevolution between supermassive black hole growth and host galaxy buildup.

Ji, Tuo; Zhou, Hongyan; Jiang, Peng; Wang, Tinggui; Ge, Jian; Wang, Huiyuan; Komossa, S.; Hamann, Fred; Zuther, Jens; Liu, Wenjuan; Lu, Honglin; Zuo, Wenwen; Yang, Chenwei; Yuan, Weimin

2015-02-01

275

Newly cultured bacteria with broad diversity isolated from eight-week continuous culture enrichments of cow feces on complex polysaccharides.  

PubMed

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

Ziemer, Cherie J

2014-01-01

276

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

277

Ecdysone-induced expression of the caspase DRONC during hormone-dependent programmed cell death in Drosophila is regulated by Broad-Complex  

Microsoft Academic Search

he steroid hormone ecdysone regulates both cell differ- entiation and cell death during insect metamorphosis, by hierarchical transcriptional regulation of a number of genes, including the Broad-Complex ( BR-C ), the zinc finger family of transcription factors. These genes in turn regulate the transcription of a number of downstream genes. DRONC, a key apical caspase in Drosophila , is the

Dimitrios Cakouros; Tasman Daish; Damali Martin; Eric H. Baehrecke; Sharad Kumar

2002-01-01

278

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

279

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

NASA Astrophysics Data System (ADS)

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

Ponti, Gabriele

280

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

281

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

282

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

NASA Technical Reports Server (NTRS)

The results of the second year of an intensive ground-based spectroscopic and photometric study of variability in the bright Seyfert 1 galaxy NGC 5548 are reported in order to study the relationship between continuum and emission-line variability. Relative to the first year of the monitoring program, the nucleus of NGC 5548 was considerably fainter and the continuum variations slower during the second year, but the continuum H-beta cross-correlation results for the two years are nearly identical. The variations in the broad H-beta emission-line lag behind those in the continuum by somewhat less than 20 days, as concluded from the first year's data.

Peterson, B. M.; Alloin, D.; Axon, D.; Balonek, T. J.; Bertram, R.; Boroson, T. A.; Christensen, J. A.; Clements, S. D.; Dietrich, M.; Elvis, M.

1992-01-01

283

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

NASA Technical Reports Server (NTRS)

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

Koratkar, Anuradha; Bond, Howard E.

1995-01-01

284

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

285

C-13H3OH in OMC-1. [and spectral line identifications combining laboratory spectroscopy with broad-band astronomical line searches  

NASA Technical Reports Server (NTRS)

Transition line data for C-13H3OH in OMC-1 were gathered with a superconducting tunnel junction receiver and a 512 channel spectrometer on a 10.4 m telescope at the Owens Valley Radio Observatory. The methanol was scanned at 236 GHz and an observational efficiency of 85 percent. The survey was carried out to complement the data base on the line frequencies of internal rotors such as methanol and thereby the resolution of the C-12/C-13 ratio toward the galactic center. The data indicated that previous emission lines attributed to CO(+) and CH3CHO are actually methanol emissions, and the associated C-12/C-13 ratio is about 30.

Blake, G. A.; Sutton, E. C.; Masson, C. R.; Phillips, T. G.; Herbst, E.; Plummer, G. M.; De Lucia, F. C.

1984-01-01

286

Ultraviolet variability of NGC 5548 - Dynamics of the continuum production region and geometry of the broad-line region  

NASA Technical Reports Server (NTRS)

Data from the 1989-1990 IUE monitoring of the Seyfert galaxy NGC 5548 are used here to analyze the continuum variability properties of the galaxy and to derive the structure or its emission-line region. The mean shape of the UV continuum is well fit by an accretion disk model with a given black hole mass and an additional component required to reproduce the observed soft X-ray flux. The continuum fluctuation power spectrum is very steep, with most of the variance coming from about 1 yr time scales. The entire optical/UV continuum rises and falls almost simultaneously, so that the logarithmic slope of the power spectrum is nearly the same for all bands, but the flux at higher photon frequencies varies with larger amplitude. The emission-line material around the nucleus may best be described by a highly ionized inner zone of high and nearly constant pressure that stretches about 4-14 light-days from the center and an outer, more weakly ionized zone of considerably lower ionization at least 20-30 light-days out.

Krolik, J. H.; Horne, Keith; Kallman, T. R.; Malkan, M. A.; Edelson, R. A.

1991-01-01

287

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

288

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

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

289

Spectrophotometry and Imaging of the Lensed, Clover Leaf Broad Absorption Line QSO 1413+117-PART II-Cyc 4 High-Imaging  

NASA Astrophysics Data System (ADS)

Observations of the gravitationally lensed "Cloverleaf" Broad Absorption Line (BAL) QSO Q1413+117 are proposed as a follow-on to a Cycle 1 proposal. Red and UV WFPC2 images and FOS spectra will be taken to achieve the following aims: (1) The red WFPC2 PC images will be used as an EARLY ACQ and to search for other component images and the lensing galaxy, followed by FOS observations to determine the galaxy's redshift. The information will be used to delineate and model the geometry of this unique gravitationally lensed BAL QSO. (2) FOS data on the QSO image components will be used to check sight-line dependent differences in the BAL profiles. The results can be used to place constraints on BAL region cloud sizes and shapes. (3) The same FOS observations will be used to constrain the sizes and shapes of Ly-alpha forest clouds and two intervening narrow absorption-line metal systems. (4) The UV and red images will be compared to search for possible sight-line dependent differences in dust-extinction. Thus, results from this study will yield relevant information on a number of different important astrophysical problems.

Turnshek, David

1994-01-01

290

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

291

Human Coronavirus EMC Does Not Require the SARS-Coronavirus Receptor and Maintains Broad Replicative Capability in Mammalian Cell Lines  

PubMed Central

ABSTRACT A new human coronavirus (hCoV-EMC) has emerged very recently in the Middle East. The clinical presentation resembled that of the severe acute respiratory syndrome (SARS) as encountered during the epidemic in 2002/2003. In both cases, acute renal failure was observed in humans. HCoV-EMC is a member of the same virus genus as SARS-CoV but constitutes a sister species. Here we investigated whether it might utilize angiotensin-converting enzyme 2 (ACE2), the SARS-CoV receptor. Knowledge of the receptor is highly critical because the restriction of the SARS receptor to deep compartments of the human respiratory tract limited the spread of SARS. In baby hamster kidney (BHK) cells, lentiviral transduction of human ACE2 (hACE2) conferred permissiveness and replication for SARS-CoV but not for hCoV-EMC. Monkey and human kidney cells (LLC-MK2, Vero, and 769-P) and swine kidney cells were permissive for both viruses, but only SARS-CoV infection could be blocked by anti-hACE2 antibody and could be neutralized by preincubation of virus with soluble ACE2. Our data show that ACE2 is neither necessary nor sufficient for hCoV-EMC replication. Moreover, hCoV-EMC, but not SARS-CoV, replicated in cell lines from Rousettus, Rhinolophus, Pipistrellus, Myotis, and Carollia bats, representing four major chiropteran families from both suborders. As human CoV normally cannot replicate in bat cells from different families, this suggests that hCoV-EMC might use a receptor molecule that is conserved in bats, pigs, and humans, implicating a low barrier against cross-host transmission. PMID:23232719

Müller, Marcel A.; Raj, V. Stalin; Muth, Doreen; Meyer, Benjamin; Kallies, Stephan; Smits, Saskia L.; Wollny, Robert; Bestebroer, Theo M.; Specht, Sabine; Suliman, Tasnim; Zimmermann, Katrin; Binger, Tabea; Eckerle, Isabella; Tschapka, Marco; Zaki, Ali M.; Osterhaus, Albert D. M. E.; Fouchier, Ron A. M.; Haagmans, Bart L.; Drosten, Christian

2012-01-01

292

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

293

The Black Hole Fundamental Plane: Revisited with a Larger Sample of Radio and X-Ray-emitting Broad-Line AGNs  

NASA Astrophysics Data System (ADS)

We use a recently released SDSS catalog of X-ray-emitting AGNs in conjunction with the FIRST radio survey to investigate the black hole (BH) fundamental plane relationship between the 1.4 GHz radio luminosity (Lr), 0.1-2.4 keV X-ray luminosity (LX), and black hole mass (M), namely, logLr=?RXlogLX+?RMlogM+constant. For this purpose, we compile a large sample of 725 broad-line AGNs, which consists of 498 radio-loud sources and 227 radio-quiet sources. We confirm that radio-loud objects have a steeper slope (?RX) with respect to radio-quiet objects and that the dependence of the BH fundamental plane on the BH mass (?RM) is weak. We also find tight correlation with a similar slope between the soft X-ray luminosity and broad emission-line luminosity for both radio-loud and radio-quiet AGNs, which implies that their soft X-ray emission is unbeamed and probably related to the accretion process. With the current larger sample, we find that there is no clear evidence of evolution for radio-quiet AGNs, while for radio-loud ones there is a weak trend in which ?RM decreases as the redshift increases. This may be understood in part as due to the observed evolution of the radio spectral index as a function of redshift. Finally, we discuss the relativistic beaming effect and other uncertainties related to the BH fundamental plane. We conclude that, although it does introduce scatter into the fundamental plane relation, Doppler boosting alone is not enough to explain the observed steeper value of ?RX in the radio-loud subsample with respect to the radio-quiet ones.

Li, Zhao-Yu; Wu, Xue-Bing; Wang, Ran

2008-12-01

294

Short-timescale Monitoring of the X-Ray, UV, and Broad Double-peak Emission Line of the Nucleus of NGC 1097  

NASA Astrophysics Data System (ADS)

Recent studies have suggested that the short-timescale (lsim 7 days) variability of the broad (~10,000 km s–1) double-peaked H? profile of the LINER nucleus of NGC 1097 could be driven by a variable X-ray emission from a central radiatively inefficient accretion flow. To test this scenario, we have monitored the NGC 1097 nucleus in X-ray and UV continuum with Swift and the H? flux and profile in the optical spectrum using SOAR and Gemini-South from 2012 August to 2013 February. During the monitoring campaign, the H? flux remained at a very low level—three times lower than the maximum flux observed in previous campaigns and showing only limited (~20%) variability. The X-ray variations were small, only ~13% throughout the campaign, while the UV did not show significant variations. We concluded that the timescale of the H? profile variation is close to the sampling interval of the optical observations, which results in only a marginal correlation between the X-ray and H? fluxes. We have caught the active galaxy nucleus in NGC 1097 in a very low activity state, in which the ionizing source was very weak and capable of ionizing just the innermost part of the gas in the disk. Nonetheless, the data presented here still support the picture in which the gas that emits the broad double-peaked Balmer lines is illuminated/ionized by a source of high-energy photons which is located interior to the inner radius of the line-emitting part of the disk.

Schimoia, Jaderson S.; Storchi-Bergmann, Thaisa; Grupe, Dirk; Eracleous, Michael; Peterson, Bradley M.; Baldwin, Jack A.; Nemmen, Rodrigo S.; Winge, Cláudia

2015-02-01

295

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

296

Evidence for two different broad-specificity oligopeptide transporters in intestinal cell line Caco-2 and colonic cell line CCD841.  

PubMed

Recently the existence of two different Na(+)-coupled oligopeptide transport systems has been described in mammalian cells. These transport systems are distinct from the previously known H(+)/peptide cotransporters PEPT1 and PEPT2, which transport only dipeptides and tripeptides. To date, the only peptide transport system known to exist in the intestine is PEPT1. Here we investigated the expression of the Na(+)-coupled oligopeptide transporters in intestinal cell lines, using the hydrolysis-resistant synthetic oligopeptides deltorphin II and [d-Ala(2),d-Leu(5)]enkephalin (DADLE) as model substrates. Caco-2 cells and CCD841 cells, both representing epithelial cells from human intestinal tract, were able to take up these oligopeptides. Uptake of deltorphin II was mostly Na(+) dependent, with more than 2 Na(+) involved in the uptake process. In contrast, DADLE uptake was only partially Na(+) dependent. The uptake of both peptides was also influenced by H(+) and Cl(-), although to a varying degree. The processes responsible for the uptake of deltorphin II and DADLE could be differentiated not only by their Na(+) dependence but also by their modulation by small peptides. Several dipeptides and tripeptides stimulated deltorphin II uptake but inhibited DADLE uptake. These modulating small peptides were, however, not transportable substrates for the transport systems that mediate deltorphin II or DADLE uptake. These two oligopeptide transport systems were also able to take up several nonopioid oligopeptides, consisting of 9-17 amino acids. This represents the first report on the existence of transport systems in intestinal cells that are distinct from PEPT1 and capable of transporting oligopeptides consisting of five or more amino acids. PMID:21307350

Chothe, Paresh; Singh, Nagendra; Ganapathy, Vadivel

2011-06-01

297

Experimental and numerical understanding of localized spin wave mode behavior in broadly tunable spatially complex magnetic configurations  

NASA Astrophysics Data System (ADS)

Spin wave modes confined in a ferromagnetic film by the spatially inhomogeneous magnetic field generated by a scanned micromagnetic tip of a ferromagnetic resonance force microscope (FMRFM) enable microscopic imaging of the internal fields and spin dynamics in nanoscale magnetic devices. Here we report a detailed study of spin wave modes in a thin ferromagnetic film localized by magnetic field configurations frequently encountered in FMRFM experiments, including geometries in which the probe magnetic moment is both parallel and antiparallel to the applied uniform magnetic field. We demonstrate that characteristics of the localized modes, such as resonance field and confinement radius, can be broadly tuned by controlling the orientation of the applied field relative to the film plane. Micromagnetic simulations accurately reproduce our FMRFM spectra allowing quantitative understanding of the localized modes. Our results reveal a general method of generating tightly confined spin wave modes in various geometries with excellent spatial resolution that significantly facilitates the broad application of FMRFM. This paves the way to imaging of magnetic properties and spin wave dynamics in a variety of contexts for uncovering new physics of nanoscale spin excitations.

Du, Chunhui; Adur, Rohan; Wang, Hailong; Manuilov, Sergei A.; Yang, Fengyuan; Pelekhov, Denis V.; Hammel, P. Chris

2014-12-01

298

Characterization of the breakpoints of a polymorphic inversion complex detects strict and broad breakpoint reuse at the molecular level.  

PubMed

Inversions are an integral part of structural variation within species, and they play a leading role in genome reorganization across species. Work at both the cytological and genome sequence levels has revealed heterogeneity in the distribution of inversion breakpoints, with some regions being recurrently used. Breakpoint reuse at the molecular level has mostly been assessed for fixed inversions through genome sequence comparison, and therefore rather broadly. Here, we have identified and sequenced the breakpoints of two polymorphic inversions-E1 and E2 that share a breakpoint-in the extant Est and E1 + 2 chromosomal arrangements of Drosophila subobscura. The breakpoints are two medium-sized repeated motifs that mediated the inversions by two different mechanisms: E1 via staggered breaks and subsequent repair and E2 via repeat-mediated ectopic recombination. The fine delimitation of the shared breakpoint revealed its strict reuse at the molecular level regardless of which was the intermediate arrangement. The occurrence of other rearrangements in the most proximal and distal extended breakpoint regions reveals the broad reuse of these regions. This differential degree of fragility might be related to their sharing the presence outside the inverted region of snoRNA-encoding genes. PMID:24881049

Puerma, Eva; Orengo, Dorcas J; Salguero, David; Papaceit, Montserrat; Segarra, Carmen; Aguadé, Montserrat

2014-09-01

299

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

NASA Astrophysics Data System (ADS)

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 v ? 20,000 km s-1 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 (v >~ 27,000 km s-1). We use these observations to estimate explosion properties and derive a total ejecta mass of ~2.7 M ?, a kinetic energy of ~1.0 × 1052 erg, and a 56Ni mass of 0.1-0.2 M ?. Nebular spectra (t > 200 days) exhibit an asymmetric double-peaked [O I] ??6300, 6364 emission profile that we associate with absorption in the supernova interior, although toroidal ejecta geometry is an alternative explanation. SN 2012ap joins SN 2009bb as another exceptional supernova that shows evidence for a central engine (e.g., black hole accretion or magnetar) capable of launching a non-negligible portion of ejecta to relativistic velocities without a coincident gamma-ray burst detection. Defining attributes of their progenitor systems may be related to notable observed properties including environmental metallicities of Z >~ Z ?, moderate to high levels of host galaxy extinction (E(B - V) > 0.4 mag), detection of high-velocity helium at early epochs, and a high relative flux ratio of [Ca II]/[O I] >1 at nebular epochs. These events support the notion that jet activity at various energy scales may be present in a wide range of supernovae.

Milisavljevic, D.; Margutti, R.; 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.

2015-01-01

300

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

301

Complex narrow-line Seyfert 1s: high spin or high inclination?  

NASA Astrophysics Data System (ADS)

Complex narrow-line Seyfert 1s (NLS1s), such as 1H 0707-495, differ from simple NLS1s like PG 1244+026 by showing stronger broad spectral features at Fe K and larger amplitude flux variability. These are correlated: the strongest Fe K features are seen during deep dips in the light curves of complex NLS1s. There are two competing explanations for these features, one where a compact X-ray source on the spin axis of a highly spinning black hole approaches the horizon and the consequent strong relativistic effects focus the intrinsic flux on to the inner edge of a thin disc, giving a dim, reflection-dominated spectrum. The other is that the deep dips are caused by complex absorption by clumps close to the hard X-ray source. The reflection-dominated model is able to reproduce the very short 30 s soft lag from reverberation seen in the complex NLS1 1H 0707-495. However, it does not explain the characteristic switch to hard lags on longer time-scales. Instead, a full model of propagating fluctuations coupled to reverberation can explain the switch in the simple NLS1 PG 1244+026 using a low spin black hole. However, PG 1244+026 has a longer reverberation lag of ˜200 s. Here we extend the successful propagation-reverberation model for the simple NLS1 PG 1244+026 to include the effect of absorption from clumps in a turbulent region above the disc. The resulting occultations of the inner accretion flow can introduce additional hard lags when relativistic effects are taken into account. This dilutes the soft lag from reverberation and shifts it to higher frequencies, making a smooth transition between the 200 s lags seen in simple NLS1s to the 30 s lags in complex NLS1s. These two classes of NLS1 could then be determined by inclination angle with respect to a clumpy, probably turbulent, failed wind structure on the disc.

Gardner, Emma; Done, Chris

2015-04-01

302

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

NASA Astrophysics Data System (ADS)

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_H \\sim 1.2^{+0.3}_{-0.3}\\times 10^{23} cm-2) column. The intrinsic X-ray luminosity (L 0.5 - 30 keV ~ 1.0 × 1043 erg s-1) is extremely weak relative to the bolometric luminosity where the 2-10 keV to bolometric luminosity ratio is ~0.03% compared to the typical values of 2%-15%. Additionally, Mrk 231 has a low X-ray-to-optical power law slope (?OX ~ -1.7). It is a local example of a low-ionization broad absorption line 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, J. R.; Risaliti, G.; Saez, C.; Stern, D.; Veilleux, S.; Walton, D. J.; Wik, D. R.; Zhang, W. W.

2014-04-01

303

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

304

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

305

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

SciTech Connect

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

Yu, Po-Chieh; Hwang, Chorng-Yuan [Graduate Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Huang, Kui-Yun; Ohyama, Youichi, E-mail: pcyu@astro.ncu.edu.tw, E-mail: hwangcy@astro.ncu.edu.tw, E-mail: ljhuang@asiaa.sinica.edu.tw, E-mail: ohyama@asiaa.sinica.edu.tw [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China)

2013-05-01

306

Broad hexagonal columnar mesophases formation in bioinspired transition-metal complexes of simple fatty acid meta-octaester derivatives of meso-tetraphenyl porphyrins.  

PubMed

A series of meta-substituted fatty acid octaester derivatives and their transition-metal complexes of meso- tetraphenyl porphyrins (TPP-8OOCR, with R = C(n-1)H(2n-1), n = 8, 12, or 16) have been prepared through very simple synthesis protocols. The thermotropic phase behavior and the liquid crystalline (LC) organization structures of the synthesized porphyrin derivatives were systematically investigated by a combination of differential scanning calorimetry (DSC), polarized optical microscopy (POM), and variable-temperature small-angle X-ray scattering/wide-angle X-ray scattering (SAXS/WAXS) techniques. The shorter octanoic acid ester substituted porphyrin (C8-TPP) did not show liquid crystallinity and its metal porphyrins exhibited an uncommon columnar mesophase. The lauric acid octaester (C12-TPP) and the palmitic acid octaester (C16-TPP) series porphyrins generated hexagonal columnar mesophase Colh. Moreover, the metal porphyrins C12-TPPM and C16-TPPM with M = Zn, Cu, or Ni, exhibited well-organized Colh mesophases of broad LC temperature ranges increasing in the order of TPPNibroadness of the discotic LC range, and the specific UV/Vis absorption and fluorescence emission behaviors make the symmetrically substituted fatty acid octaester porphyrins and their metal complexes very attractive for variant applications. PMID:25619819

Wu, Bin; Chen, Keyang; Deng, Yuchen; Chen, Jian; Liu, Chengjie; Cheng, Rongshi; Chen, Dongzhong

2015-02-23

307

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

308

A vaccine based on the rhesus cytomegalovirus UL128 complex induces broadly neutralizing antibodies in rhesus macaques.  

PubMed

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; Barry, Peter A; Diamond, Don J

2013-02-01

309

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

PubMed Central

Through transposon mutagenesis and DNA sequence analysis, the main disease determinant of the entomopathogenic bacterium Yersinia entomophaga MH96 was localized to an ?32-kb pathogenicity island (PAI) designated PAIYe96. Residing within PAIYe96 are seven open reading frames that encode an insecticidal toxin complex (TC), comprising not only the readily recognized toxin complex A (TCA), TCB, and TCC components but also two chitinase proteins that form a composite TC molecule. The central TC gene-associated region (?19 kb) of PAIYe96 was deleted from the Y. entomophaga MH96 genome, and a subsequent bioassay of the ?TC derivative toward Costelytra zealandica larvae showed it to be innocuous. Virulence of the ?TC mutant strain could be restored by the introduction of a clone containing the entire PAIYe96 TC gene region. As much as 0.5 mg of the TC is released per 100 ml of Luria-Bertani broth at 25°C, while at 30 or 37°C, no TC could be detected in the culture supernatant. Filter-sterilized culture supernatants derived from Y. entomophaga MH96, but not from the ?TC strain grown at temperatures of 25°C or less, were able to cause mortality. The 50% lethal doses (LD50s) of the TC toward diamondback moth Plutella xylostella and C. zealandica larvae were defined as 30 ng and 50 ng, respectively, at 5 days after ingestion. Histological analysis of the effect of the TC toward P. xylostella larva showed that within 48 h after ingestion of the TC, there was a general dissolution of the larval midgut. PMID:21278295

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

2011-01-01

310

A Germin-Like Protein Gene Family Functions as a Complex Quantitative Trait Locus Conferring Broad-Spectrum Disease Resistance in Rice1[W][OA  

PubMed Central

Plant disease resistance governed by quantitative trait loci (QTL) is predicted to be effective against a broad spectrum of pathogens and long lasting. Use of these QTL to improve crop species, however, is hindered because the genes contributing to the trait are not known. Five disease resistance QTL that colocalized with defense response genes were accumulated by marker-aided selection to develop blast-resistant varieties. One advanced backcross line carrying the major-effect QTL on chromosome (chr) 8, which included a cluster of 12 germin-like protein (OsGLP) gene members, exhibited resistance to rice (Oryza sativa) blast disease over 14 cropping seasons. To determine if OsGLP members contribute to resistance and if the resistance was broad spectrum, a highly conserved portion of the OsGLP coding region was used as an RNA interference trigger to silence a few to all expressed chr 8 OsGLP family members. Challenge with two different fungal pathogens (causal agents of rice blast and sheath blight diseases) revealed that as more chr 8 OsGLP genes were suppressed, disease susceptibility of the plants increased. Of the 12 chr 8 OsGLPs, one clustered subfamily (OsGER4) contributed most to resistance. The similarities of sequence, gene organization, and roles in disease resistance of GLP family members in rice and other cereals, including barley (Hordeum vulgare) and wheat (Triticum aestivum), suggest that resistance contributed by the chr 8 OsGLP is a broad-spectrum, basal mechanism conserved among the Gramineae. Natural selection may have preserved a whole gene family to provide a stepwise, flexible defense response to pathogen invasion. PMID:19011003

Manosalva, Patricia M.; Davidson, Rebecca M.; Liu, Bin; Zhu, Xiaoyuan; Hulbert, Scot H.; Leung, Hei; Leach, Jan E.

2009-01-01

311

A one-dimensional Chandrasekhar-mass delayed-detonation model for the broad-lined Type Ia supernova 2002bo  

NASA Astrophysics Data System (ADS)

We present 1D non-local thermodynamic equilibrium time-dependent radiative transfer simulations of a Chandrasekhar-mass delayed-detonation model which synthesizes 0.51 M? of 56Ni, and confront our results to the Type Ia supernova (SN Ia) 2002bo over the first 100 d of its evolution. Assuming only homologous expansion, this same model reproduces the bolometric and multiband light curves, the secondary near-infrared (NIR) maxima, and the optical and NIR spectra. The chemical stratification of our model qualitatively agrees with previous inferences by Stehle et al., but reveals significant quantitative differences for both iron-group and intermediate-mass elements. We show that ±0.1 M? (i.e. ±20 per cent) variations in 56Ni mass have a modest impact on the bolometric and colour evolution of our model. One notable exception is the U band, where a larger abundance of iron-group elements results in less opaque ejecta through ionization effects, our model with more 56Ni displaying a higher near-ultraviolet flux level. In the NIR range, such variations in 56Ni mass affect the timing of the secondary maxima but not their magnitude, in agreement with observational results. Moreover, the variation in the I, J, and Ks magnitudes is less than 0.1 mag within ˜10 d from bolometric maximum, confirming the potential of NIR photometry of SNe Ia for cosmology. Overall, the delayed-detonation mechanism in single Chandrasekhar-mass white dwarf progenitors seems well suited for SN 2002bo and similar SNe Ia displaying a broad Si II 6355 Å line. Whatever multidimensional processes are at play during the explosion leading to these events, they must conspire to produce an ejecta comparable to our spherically symmetric model.

Blondin, Stéphane; Dessart, Luc; Hillier, D. John

2015-04-01

312

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

313

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

314

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

315

The power of line-narrowing techniques: Applications to photosynthetic chromoprotein complexes and autofluorescent proteins  

Microsoft Academic Search

Laser spectroscopic techniques at low temperature, such as fluorescence line-narrowing and hole burning, enable an increase\\u000a of spectral resolution by a factor of 103–105 compared to conventional spectroscopy at room temperature. With these methods, it is possible to retrieve a fingerprint of\\u000a the species involved and to measure the rates of dynamic processes that normally remain hidden in the broad

R. Purchase; S. Bonsma; S. Jezowski; J. Gallus; F. Könz; S. L. Volker

2005-01-01

316

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

317

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

318

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

319

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

NASA Astrophysics Data System (ADS)

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

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

1996-07-01

320

Large-Scale, Lineage-Specific Expansion of a Bric-a-Brac/Tramtrack/Broad Complex Ubiquitin-Ligase Gene Family in Rice[W  

PubMed Central

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

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

2007-01-01

321

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

322

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.

323

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

PubMed

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

2013-12-15

324

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

325

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

326

The structures of L-rhamnose isomerase from Pseudomonas stutzeri in complexes with L-rhamnose and D-allose provide insights into broad substrate specificity.  

PubMed

Pseudomonas stutzeri L-rhamnose isomerase (P. stutzeri L-RhI) can efficiently catalyze the isomerization between various aldoses and ketoses, showing a broad substrate specificity compared to L-RhI from Escherichia coli (E. coli L-RhI). To understand the relationship between structure and substrate specificity, the crystal structures of P. stutzeri L-RhI alone and in complexes with L-rhamnose and D-allose which has different configurations of C4 and C5 from L-rhamnose, were determined at a resolution of 2.0 A, 1.97 A, and 1.97 A, respectively. P. stutzeri L-RhI has a large domain with a (beta/alpha)(8) barrel fold and an additional small domain composed of seven alpha-helices, forming a homo tetramer, as found in E. coli L-RhI and D-xylose isomerases (D-XIs) from various microorganisms. The beta1-alpha1 loop (Gly60-Arg76) of P. stutzeri L-RhI is involved in the substrate binding of a neighbouring molecule, as found in D-XIs, while in E. coli L-RhI, the corresponding beta1-alpha1 loop is extended (Asp52-Arg78) and covers the substrate-binding site of the same molecule. The complex structures of P. stutzeri L-RhI with L-rhamnose and D-allose show that both substrates are nicely fitted to the substrate-binding site. The part of the substrate-binding site interacting with the substrate at the 1, 2, and 3 positions is equivalent to E. coli L-RhI, and the other part interacting with the 4, 5, and 6 positions is similar to D-XI. In E. coli L-RhI, the beta1-alpha1 loop creates an unique hydrophobic pocket at the the 4, 5, and 6 positions, leading to the strictly recognition of L-rhamnose as the most suitable substrate, while in P. stutzeri L-RhI, there is no corresponding hydrophobic pocket where Phe66 from a neighbouring molecule merely forms hydrophobic interactions with the substrate, leading to the loose substrate recognition at the 4, 5, and 6 positions. PMID:17141803

Yoshida, Hiromi; Yamada, Mitsugu; Ohyama, Yuya; Takada, Goro; Izumori, Ken; Kamitori, Shigehiro

2007-02-01

327

3-mm spectral line survey of two lines of sight towards two typical cloud complexes in the Galactic Centre  

NASA Astrophysics Data System (ADS)

We present the results of two Mopra 3-mm spectral line surveys of the lines of sight (LOS) towards the Galactic Centre (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 per cent) for the GC physical conditions. The derived abundances 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 LOSs with those in typical Galactic photodissociation regions (PDRs) and starbursts galaxies does not show any clear trend to distinguish between ultraviolet- and X-ray-induced chemistries. We propose that the CS/HOC+ ratio could be used as a tracer of the PDR components in the molecular clouds in the nuclei of galaxies.

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

2015-02-01

328

Antioxidant Enzyme Inhibitor Role of Phosphine Metal Complexes in Lung and Leukemia Cell Lines  

PubMed Central

Phosphine metal complexes have been recently evaluated in the field of cancer therapy. In this research, the cytotoxic effects of some metal phosphines {[PdCl2((CH2OH)2PCH2)2NCH3] (C1), [RuCl2(((CH2OH)2PCH2)2NCH3)2] (C2), [PtCl2((Ph2PCH2)2NCH3)(timin)2] (C3)} on K562 (human myelogenous leukemia cell line) and A549 (adenocarcinomic human alveolar basal epithelial cells) cells were investigated using the MTT test. C1 and C2 are water-soluble metal complexes, which may have some advantages in in vitro and in vivo studies. The effects of the above-mentioned metal complexes on thioredoxin reductase (TrxR) (EC: 1.8.1.9), glutathione peroxidase (GPx) (EC: 1.11.1.9), and catalase (Cat) (EC: 1.11.1.6) enzymes were also tested. The results of this research showed that all three metal complexes indicated dose-dependent cytotoxicity on A549 and K562 cell lines and that the complexes inhibited different percentages of the TrxR, GPx, and Cat enzymes of these tumor cells. PMID:25610346

Kele?, Tu?ba; Serinda?, Osman

2014-01-01

329

Structural measurements and cell line studies of the copper-PEG-Rifampicin complex against Mycobacterium tuberculosis.  

PubMed

The bacterium responsible for tuberculosis is increasing its resistance to antibiotics resulting in new multidrug-resistant Mycobacterium tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB). In this study, several analytical techniques including NMR, FT-ICR, MALDI-MS, LC-MS and UV/Vis are used to study the copper-Rifampicin-Polyethylene glycol (PEG-3350) complex. The copper (II) cation is a carrier for the antibiotic Rifampicin as well as nutrients for the bacterium. The NIH-NIAID cell line containing several Tb strains (including antibiotic resistant strains) is tested against seven copper-PEG-RIF complex variations. PMID:25575660

Manning, Thomas; Mikula, Rachel; Wylie, Greg; Phillips, Dennis; Jarvis, Jackie; Zhang, Fengli

2015-02-01

330

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

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

331

Complex saddle points and disorder lines in QCD at finite temperature and density  

NASA Astrophysics Data System (ADS)

The properties and consequences of complex saddle points are explored in phenomenological models of QCD at nonzero temperature and density. Such saddle points are a consequence of the sign problem and should be considered in both theoretical calculations and lattice simulations. Although saddle points in finite-density QCD are typically in the complex plane, they are constrained by a symmetry that simplifies analysis. We model the effective potential for Polyakov loops using two different potential terms for confinement effects and consider three different cases for quarks: very heavy quarks, massless quarks without modeling of chiral symmetry breaking effects, and light quarks with both deconfinement and chiral symmetry restoration effects included in a pair of Polyakov-Nambu-Jona Lasinio models. In all cases, we find that a single dominant complex saddle point is required for a consistent description of the model. This saddle point is generally not far from the real axis; the most easily noticed effect is a difference between the Polyakov loop expectation values ?TrFP ? and ?TrFP†? , and that is confined to a small region in the ? -T plane. In all but one case, a disorder line is found in the region of critical and/or crossover behavior. The disorder line marks the boundary between exponential decay and sinusoidally modulated exponential decay of correlation functions. Disorder line effects are potentially observable in both simulation and experiment. Precision simulations of QCD in the ? -T plane have the potential to clearly discriminate between different models of confinement.

Nishimura, Hiromichi; Ogilvie, Michael C.; Pangeni, Kamal

2015-03-01

332

Elevated levels of eukaryotic translation initiation factor eIF-4E, mRNA in a broad spectrum of transformed cell lines  

Microsoft Academic Search

Translation initiation factor eIF-4E, which binds to the 5? cap structure of eukaryotic mRNAs, is believed to play an important role in the control of cell growth. Over-expression of eIF-4E in fibroblasts results in their malignant transformation. However, no information on eIF-4E expression in established transformed cell lines has been available. We report here that a variety of tumor cell

Yohei Miyagi; Akinori Sugiyama; Akio Asai; Tomoko Okazaki; Yoshiyuki Kuchino; Sylvia J. Kerr

1995-01-01

333

Comparison of complex Langevin and mean field methods applied to effective Polyakov line models  

NASA Astrophysics Data System (ADS)

Effective Polyakov line models, derived from SU(3) gauge-matter systems at finite chemical potential, have a sign problem. In this article I solve two such models, derived from SU(3) gauge-Higgs and heavy quark theories by the relative weights method, over a range of chemical potentials where the sign problem is severe. Two values of the gauge-Higgs coupling are considered, corresponding to a heavier and a lighter scalar particle. Each model is solved via the complex Langevin method, following the approach of Aarts and James, and also by a mean field technique. It is shown that where the results of mean field and complex Langevin agree, they agree almost perfectly. Where the results of the two methods diverge, it is found that the complex Langevin evolution has a branch cut crossing problem, associated with a logarithm in the action, that was pointed out by Møllgaard and Splittorff.

Greensite, Jeff

2014-12-01

334

{\\it NuSTAR} Reveals an Intrinsically X-ray Weak Broad Absorption Line Quasar in the Ultraluminous Infrared Galaxy Markarian 231  

E-print Network

We present high-energy (3--30 keV) {\\it 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 {\\it 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$_{\\rm H} \\sim1.2^{+0.3}_{-0.3}\\times10^{23}$ cm$^{-2}$) column. The intrinsic X-ray luminosity (L$_{\\rm 0.5-30 keV}\\sim1.0\\times10^{43}$ erg s$^{1}$) is extremely weak relative to the bolometric luminosity where the 2--10 keV to bolometric luminosity ratio is $\\sim$0.03% compared to the typical values of 2--15%. Additionally, Mrk 231 has a low X-ray-to-optical power law slope ($\\alpha_{\\rm OX}\\sim-1.7$). It is a local example of a low-ionization broad absorpti...

Teng, Stacy H; 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, J R; Risaliti, G; Saez, C; Stern, D; Veilleux, S; Walton, D J; Wik, D R; Zhang, W W

2014-01-01

335

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

PubMed

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

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

2013-10-01

336

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

337

Sagittarius A Molecular Cloud Complex in H13CO+ and Thermal SiO Emission Lines  

NASA Astrophysics Data System (ADS)

We present results of a high-resolution wide-field mapping observation of the Sagittarius A (Sgr A) molecular cloud complex in H13CO+ J = 1-0 and thermal SiO J = 2-1 emission lines with the 25-beam receiver of the 100 GHz band operating on the Nobeyama Radio Observatory 45-m telescope. The mapping area covers a 0.°5 × 0.°5 area involving several named molecular clouds, for example GCM-0.02-0.07, GCM-0.13-0.08, GCM 0.11-0.11, the Sickle molecular cloud, the Arched filaments molecular cloud, and so on. The data have an effective angular resolution of 26''. The H13CO+ emission line is a famous tracer of molecular gas mass because the line is optically thin, even in the Galactic center region, and is not emphasized by shock. The emission line presents a clumpy distribution of the molecular cloud. The averaged fractional abundance in the Sgr A complex is N(H13CO+)/NH2? (1.8±0.4)× 10-11, comparing the LTE mass and the virial theorem mass. The SiO emission line is a famous and reliable tracer of shocked molecular gas. We find many molecular clouds that are remarkable only in the SiO emission line. Such molecular clouds have a large velocity width of up to 60 km s-. The brightness temperature ratio is up to TB(SiO)/TB(H13CO+)? 8. The features are dominated by shock SiO-enriched gas. In such clouds, the ratio of the fractional abundance of SiO and H13CO+ molecules is X(SiO)/X(H13CO+)˜ 100. The features are presumably made by supernova remnants. We found a prototypical example in GCM-0.02-0.07. It has two distinct structures. One is a ridge-like structure contacting with the Sgr A East shell; another is an expanding shell-like structure. There is a wide-velocity width ridge of SiO-enriched gas in GCM 0.11-0.11, which is adjacent to Vertical filaments. This suggests that the collision with the molecular cloud accelerates relativistic electrons, which illuminate the Vertical filaments-Polarized Plumes complex.

Tsuboi, Masato; Tadaki, Ken-Ichi; Miyazaki, Atsushi; Handa, Toshihiro

2011-08-01

338

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

339

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

340

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

341

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

342

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.pouclet@sfr.fr23 24 Keywords: Cameroon Volcanic Line, Manengouba volcano, alkaline magmatism, Quaternary25 is related to four chronological stages: 1) forming31 of the early Manengouba shield volcano between 1

Boyer, Edmond

343

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

PubMed

This paper discusses the first setup for on-line qualitative and quantitative comprehensive two-dimensional gas chromatography (GC × GC) of complex hydrocarbon mixtures. A built-in 4-port 2-way valve allows switching between flame ionization detection (FID) and time-of-flight mass spectrometry (TOF-MS) between runs, without the need to cool down and vent the MS. Proper selection of GC carrier gas flow rates enables maximal agreement between the obtained chromatograms in both configurations. For on-line analysis of reactor effluents, a dedicated sampling system allows automatic sampling of the hot reactor effluent gases and immediate injection of the sample on the GC × GC. To determine a complete effluent composition in a single run of the GC × GC, a subzero oven starting temperature was employed. Modulation is started when the oven temperature reaches 40°C, thus dividing the chromatogram in a conventional 1D and a comprehensive 2D part. This work illustrates the mature and robust character of GC × GC, extending its capabilities from mere laboratory use to on-line routine analysis for industrial processes in the (petro-)chemical industry. PMID:20444456

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

2010-10-22

344

Six Years of Fermi-LAT and Multi-Wavelength Monitoring of the Broad-Line Radio Galaxy 3c 120: Jet Dissipation At Sub-Parsec Scales from the Central Engine  

NASA Astrophysics Data System (ADS)

We present multi-wavelength monitoring results for the broad-line radio galaxy 3C 120 in the MeV/GeV, sub-millimeter, and 43 GHz bands over 6 yr. Over the past 2 yr, the Fermi-Large Area Telescope sporadically detected 3C 120 with high significance and the 230 GHz data also suggest an enhanced activity of the source. After the MeV/GeV detection from 3C 120 in MJD 56240–56300, 43 GHz Very Long Baseline Array (VLBA) monitoring revealed a brightening of the radio core, followed by the ejection of a superluminal knot. Since we observed the ?-ray and VLBA phenomena in temporal proximity to each other, it is naturally assumed that they are physically connected. This assumption was further supported by the subsequent observation that the 43 GHz core brightened again after a ?-ray flare occurred around MJD 56560. We can then infer that the MeV/GeV emission took place inside an unresolved 43 GHz core of 3C 120 and that the jet dissipation occurred at sub-parsec distances from the central black hole (BH), if we take the distance of the 43 GHz core from the central BH as ˜0.5 pc, as previously estimated from the time lag between X-ray dips and knot ejections. Based on our constraints on the relative locations of the emission regions and energetic arguments, we conclude that the ? rays are more favorably produced via the synchrotron self-Compton process, rather than inverse Compton scattering of external photons coming from the broad line region or hot dusty torus. We also derived the electron distribution and magnetic field by modeling the simultaneous broadband spectrum.

Tanaka, Y. T.; Doi, A.; Inoue, Y.; Cheung, C. C.; Stawarz, L.; Fukazawa, Y.; Gurwell, M. A.; Tahara, M.; Kataoka, J.; Itoh, R.

2015-02-01

345

Antimony(III) complexes with 2-benzoylpyridine-derived thiosemicarbazones: cytotoxicity against human leukemia cell lines.  

PubMed

The antimony(III) complexes [Sb(2Bz4DH)Cl(2)] (1), [Sb(H2Bz4M)Cl(3)] x 2 H(2)O (2) and [Sb(2Bz4Ph)Cl(2)] (3) were obtained with 2-benzoylpyridine thiosemicarbazone (H2Bz4DH) and its N(4)-methyl (H2Bz4M) and N(4)-phenyl (H2Bz4Ph) derivatives. H2Bz4DH, H2Bz4Ph and complexes (1-3) exhibited high cytotoxic activity against HL-60 and Jurkat human leukemia cell lines. When these compounds were tested against HL-60 cells with ectopic expression of BcrAbl, Bcl-2 or Bcl-X(L), which confer resistance to apoptosis against a variety of death-inducing agents, the cytotoxicity was much lower, indicating apoptosis to be part of their mechanism of action. The cytotoxic activity of complexes 2 and 3 against HL-60 and Jurkat cells was significantly higher than that of the corresponding thiosemicarbazones, suggesting coordination to be an interesting strategy of cytotoxic dose reduction. PMID:20576328

Reis, Débora C; Pinto, Mauro C X; Souza-Fagundes, Elaine M; Wardell, Solange M S V; Wardell, James L; Beraldo, Heloisa

2010-09-01

346

Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. 5: Variability of the ultraviolet continuum and emission lines of NGC 3783  

NASA Technical Reports Server (NTRS)

We report on the results of intensive ultraviolet spectral monitoring of the Seyfert 1 galaxy NGC 3783. The nucleus of NGC 3783 was observed with the International Ultraviolet Explorer satellite on a regular basis for a total of 7 months, once every 4 days for the first 172 days and once every other day for the final 50 days. Significant variability was observed in both continuum and emission-line fluxes. The light curves for the continuum fluxes exhibited two well-defined local minima or 'dips,' the first lasting is less than or approximately 20 days and the second is less than or approximately 4 days, with additional episodes of relatively rapid flickering of approximately the same amplitude. As in the case of NGC 5548 (the only other Seyfert galaxy that has been the subject of such an intensive, sustained monitoring effort), the largest continuum variations were seen at the shortest wavelengths, so that the continuum became 'harder' when brighter. The variations in the continuum occurred simultaneously at all wavelengths (delta(t) is less than 2 days). Generally, the amplitude of variability of the emission lines was lower than (or comparable to) that of the continuum. Apart from Mg II (which varied little) and N V (which is relatively weak and badly blended with Ly(alpha), the light curves of the emission lines are very similar to the continuum light curves, in each case with a small systematic delay or 'lag.' As for NGC 5548, the highest ionization lines seem to respond with shorter lags than the lower ionization lines. The lags found for NGC 3783 are considerably shorter than those obtained for NGC 5548, with values of (formally) approximately 0 days for He II + O III), and approximately 4 days for Ly(alpha) and C IV. The data further suggest lags of approximately 4 days for Si IV + O IV) and 8-30 days for Si III + C III). Mg II lagged the 1460 A continuum by approximately 9 days, although this result depends on the method of measuring the line flux and may in fact be due to variability of the underlying Fe II lines. Correlation analysis further shows that the power density spectrum contains substantial unresolved power over timescales of is less than or approximately 2 days, and that the character of the continuum variability may change with time.

Reichert, G. A.; Rodriguez-Pascual, P. M.; Alloin, D.; Clavel, J.; Crenshaw, D. M.; Kriss, G. A.; Krolik, J. H.; Malkan, M. A.; Netzer, H.; Peterson, B. M.

1994-01-01

347

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

348

Three lines to view language network. Comment on "Approaching human language with complex networks" by Cong and Liu  

NASA Astrophysics Data System (ADS)

Language is a kind of complex dynamic network [1-3]. The complexity of language system embodies the interaction and evolution of various languages symbols. The neural network is the physiological basis of language generating and understanding. It also provides a basis to researches on language system by adopting complex network technology and social network analysis. The review [4] gives us three lines to view researches of language network in recent years.

Zhao, Yiyi

2014-12-01

349

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

SciTech Connect

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

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

2011-04-15

350

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

351

Zinc(II) complexes with dithiocarbamato derivatives: structural characterisation and biological assays on cancerous cell lines.  

PubMed

Zinc is one of the most important trace elements in the body and it is essential as a cofactor for the structure and function of a number of cellular molecules including enzymes, transcription factors, cellular signalling proteins and DNA repair enzymes. On the other hand, recent studies have shown that zinc could play a role both in the development of various cancers and in the induction of apoptosis in some cell types, however, no established common relationships of zinc with cancer development and progression have been identified. To date, in our research group different metal-dithiocarbamato complexes have been designed that were expected to resemble the main features of cisplatin together with higher activity, improved selectivity and bioavailability, and lower side-effects. On the basis of the obtained encouraging achievements with other metals (such as gold and copper) we have decided to enlarge the studies to the complexes of zinc(II) using the same ligands. Hereby, we report the results on the synthesis and characterisation of ZnL(2) complexes with five different dithiocarbamato derivatives, such as dimethyl-(DMDT), pyrrolidine-(PyDT), methyl-(MSDT), ethyl-(ESDT) and tert-butyl-(TSDT) sarcosinedithiocarbamate. All the obtained compounds have fully been characterised by means of several spectroscopic techniques. In addition, the crystal structure of [Zn(MSDT)(2)](2) dinuclear complex is also reported. In order to evaluate the in vitro cytotoxic properties, some biological assays have been carried out on a panel of human tumour cell lines sensible and resistant to cisplatin. Some of the tested compounds show cytotoxicity levels comparable or even greater than the reference drug (cisplatin). PMID:23085593

Nagy, Eszter Márta; Sitran, Sergio; Montopoli, Monica; Favaro, Monica; Marchiò, Luciano; Caparrotta, Laura; Fregona, Dolores

2012-12-01

352

On-line gel permeation chromatography/nuclear magnetic resonance of complex polymer formulations.  

PubMed

Separation of synthetic polymer mixtures by gel permeation chromatography (GPC), followed by on-line detection using a 500 MHz nuclear magnetic resonance (NMR) spectrometer, has been demonstrated using three different polymer formulations as examples. The mobile phase used in all cases was deutero-chloroform, and an inexpensive commercially available flow cell was used as a link between the separation and detection stages of the experiment. Using this technique it is possible to derive chemical information relating to specific molecular sizes of polymer mixtures, and not just the size-averaged information that would be obtained from standard NMR experiments. This provides an invaluable tool for the deformulation of complex mixtures such as those found in the surfactants and adhesives industries. PMID:15479530

Robertson, D F; Heron, J E; Beckett, M C

2004-09-01

353

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

354

Complex modes and new amplification regimes in periodic multi transmission lines interacting with an electron beam  

E-print Network

We show the existence of a new regime of operation for travelling wave tubes (TWTs) composed of slow-wave periodic structures that support two or more electromagnetic modes, with at least two synchronized with an electron beam. The interaction between the slow-wave structure and an electron beam is quantified using a multi transmission line approach (MTL) and transfer matrix analysis leading to the identification of modes with complex Bloch wavenumber. In particular, we report a new operation condition for TWTs based on an electron beam synchronous to two modes exhibiting a degeneracy condition near a band edge in a MTL slow-wave periodic structure. We show a phenomenological change in the band structure of periodic TWT where we observe at least two growing modal cooperating solutions as opposed to a uniform MTL interacting with an electron beam where there is strictly only one growing mode solution.

Othman, Mohamed; Capolino, Filippo

2014-01-01

355

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

PubMed Central

The immortal and totipotent properties of the germ line depend on determinants within the germ plasm. A common characteristic of germ plasm across phyla is the presence of germ granules, including P granules in Caenorhabditis elegans, which are typically associated with the nuclear periphery. In C. elegans, nuclear pore complex (NPC)–like FG repeat domains are found in the VASA-related P-granule proteins GLH-1, GLH-2, and GLH-4 and other P-granule components. We demonstrate that P granules, like NPCs, are held together by weak hydrophobic interactions and establish a size-exclusion barrier. Our analysis of intestine-expressed proteins revealed that GLH-1 and its FG domain are not sufficient to form granules, but require factors like PGL-1 to nucleate the localized concentration of GLH proteins. GLH-1 is necessary but not sufficient for the perinuclear location of granules in the intestine. Our results suggest that P granules extend the NPC environment in the germ line and provide insights into the roles of the PGL and GLH family proteins. PMID:21402789

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

2011-01-01

356

Long-Term Continuous Monitoring of the Broad-Line Radio Galaxies 3C 390.3 and 3C 120 with the Rossi X-Ray Timing Explorer  

NASA Astrophysics Data System (ADS)

We present a study of the flux and spectral variability of the two broad-line radio galaxies (BLRGs) 3C 390.3 and 3C 120, observed almost daily with the Rossi X-Ray Timing Explorer for nearly 2 months each in 1996 and 1997, respectively. Our original motivation for this study was to search for systematic differences between BLRGs and their radio-quiet counterparts, the Seyfert galaxies, whose temporal and spectral behavior is better studied. We find that both 3C 390.3 and 3C 120 are highly variable but in different ways, and we quantify this difference by means of a structure function analysis. 3C 390.3 is significantly more variable than 3C 120, despite its jet's larger inclination angle, implying either that the X-ray variability is not dominated by the jet or that two different variability processes are simultaneously at work in 3C 390.3. We perform an energy-selected and time-resolved analysis based on the fractional variability amplitude and find that the variability amplitude of both objects is strongly anticorrelated with the energy. This last result, along with the correlated change of the photon index with the X-ray continuum flux, can be qualitatively explained within the scenario of thermal Comptonization, generally invoked for radio-quiet active galaxies. Moreover, the time-resolved and energy-selected fractional variability analysis shows a trend opposite to that observed in jet-dominated active galactic nuclei (blazars), suggesting only a minor contribution of the jet to the X-ray properties of BLRGs. Time-averaged spectral analysis indicates the presence of a strong resolved Fe K? line with a centroid at 6.4 keV and a weak (?/2?~=0.1-0.4) reflection component in both objects. The overall PCA+HEXTE spectra are best fitted with the constant density ionization model of Ross & Fabian, but with a modest ionization parameter. We perform a time-resolved spectral analysis of 3C 390.3 with the aim of constraining the delay between Fe K? line and continuum variability; however, the limited signal-to-noise ratio of the line flux hampers a thorough study of the line variability.

Gliozzi, Mario; Sambruna, Rita M.; Eracleous, Michael

2003-02-01

357

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

358

Broad-band beam buncher  

DOEpatents

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

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

1986-01-01

359

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

360

The Broad Way  

ERIC Educational Resources Information Center

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

Butler, Kevin

2008-01-01

361

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

Microsoft Academic Search

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

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

1985-01-01

362

Tad, a Neurospora LINE-like retrotransposon exhibits a complex pattern of transcription.  

PubMed

Tad is a LINE-like element from Neurospora. Inactive Tad elements have been found in all strains of Neurospora examined; however, active copies of Tad were initially found in a single strain (Adiopodoumé) collected from nature. Active Tad elements can be transferred to laboratory strains by means of crosses, heterokaryons or by transformation with cloned active elements. We have analyzed the pattern of transcripts from Tad elements present in strains derived from Adiopodoumé containing either high or low copy numbers of active Tad. In both kinds of strains we found a complex set of discrete polyadenylated transcripts. As expected, a full-length transcript was detected with 5' and 3' ends that coincide with the consensus 5' and 3' ends of the Tad element. Two additional transcripts with the same polarity as the full-length transcript were identified. One of these plus-strand transcripts is 2.0 kb in length with a 5' end identical to that of the full-length transcript and an internal polyadenylation site. The other (4.2 kb) has an internal start site with termination occurring at the 3' consensus end of the element. The 2.0-kb transcript encodes all of ORF1. The 4.2 kb transcript could encode a 5' truncated version of ORF2. Two minusstrand transcripts were also consistently identified. These represent overlapping transcripts from the 3' tail of Tad. These transcripts share a small intron and 3' polyadenylation site. Their 5' start sites are both internal to the consensus 3' end of Tad. Possible functions of this complex array of transcripts are discussed. PMID:8804386

Sewell, E; Kinsey, J A

1996-08-27

363

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

SciTech Connect

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

Gomez Del Campo, J.

1996-10-01

364

Experimental characterization of phase tuning using fine wavelength offsets in a tunable complex-coefficient optical tapped-delay-line.  

PubMed

We use fine-detuning of pump wavelengths to adjust the tap phases in a complex-coefficient optical tapped-delay-line that utilizes conversion/dispersion-based delays and nonlinear wave mixing. Full 2? phase tuning is demonstrated by detuning the frequency of laser pumps by <20??GHz, which shows close agreement with theory. PMID:24562193

Khaleghi, Salman; Chitgarha, Mohammad Reza; Yilmaz, Omer F; Tur, Moshe; Haney, Michael W; Langrock, Carsten; Fejer, Martin M; Willner, Alan E

2014-02-15

365

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

366

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

367

Broad-band beam buncher  

DOEpatents

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

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

1984-03-20

368

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

2011-09-26

369

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

370

Broad Bandwidth Telecommunications Systems.  

ERIC Educational Resources Information Center

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

Sodolski, John

371

Aspects of Broad Folksonomies  

Microsoft Academic Search

Folksonomies, collaboratively created sets of metadata, are becoming more and more important for organising information and knowledge of communites in the Web. While for a single user the difference to keyword assignment is marginal, the power of folksonomies emerges from the collaborative aspects. Folksonomies are already issue of research. Within this publication we analyse underlying statistical properties of broad folksonomies

Mathias Lux; Michael Granitzer; Roman Kern

2007-01-01

372

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

Microsoft Academic Search

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

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

373

XMM-Newton observation of the ULIRG NGC 6240: The physical nature of the complex Fe K line emission  

E-print Network

We report on an XMM-Newton observation of the ultraluminous infrared galaxy NGC 6240. The 0.3-10 keV spectrum can be successfully modelled with: (i) three collisionally ionized plasma components with temperatures of about 0.7, 1.4, and 5.5 keV; (ii) a highly absorbed direct power-law component; and (iii) a neutral Fe K_alpha and K_beta line. We detect a significant neutral column density gradient which is correlated with the temperature of the three plasma components. Combining the XMM-Newton spectral model with the high spatial resolution Chandra image we find that the temperatures and the column densities increase towards the center. With high significance, the Fe K line complex is resolved into three distinct narrow lines: (i) the neutral Fe K_alpha line at 6.4 keV; (ii) an ionized line at about 6.7 keV; and (iii) a higher ionized line at 7.0 keV (a blend of the Fe XXVI and the Fe K_beta line). While the neutral Fe K line is most probably due to reflection from optically thick material, the Fe XXV and Fe XXVI emission arises from the highest temperature ionized plasma component. We have compared the plasma parameters of the ultraluminous infrared galaxy NGC 6240 with those found in the local starburst galaxy NGC 253. We find a striking similarity in the plasma temperatures and column density gradients, suggesting a similar underlying physical process at work in both galaxies.

Th. Boller; R. Keil; G. Hasinger; E. Costantini; R.