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Sample records for line region structure

  1. Line Emission from Radiation-pressurized H II Regions. I. Internal Structure and Line Ratios

    NASA Astrophysics Data System (ADS)

    Yeh, Sherry C. C.; Verdolini, Silvia; Krumholz, Mark R.; Matzner, Christopher D.; Tielens, Alexander G. G. M.

    2013-05-01

    The emission line ratios [O III] λ5007/Hβ and [N II] λ6584/Hα have been adopted as an empirical way to distinguish between the fundamentally different mechanisms of ionization in emission-line galaxies. However, detailed interpretation of these diagnostics requires calculations of the internal structure of the emitting H II regions, and these calculations depend on the assumptions one makes about the relative importance of radiation pressure and stellar winds. In this paper, we construct a grid of quasi-static H II region models to explore how choices about these parameters alter H II regions' emission line ratios. We find that when radiation pressure is included in our models, H II regions reach a saturation point beyond which further increase in the luminosity of the driving stars does not produce any further increase in effective ionization parameter, and thus does not yield any further alteration in an H II region's line ratio. We also show that if stellar winds are assumed to be strong, the maximum possible ionization parameter is quite low. As a result of this effect, it is inconsistent to simultaneously assume that H II regions are wind-blown bubbles and that they have high ionization parameters; some popular H II region models suffer from this inconsistency. Our work in this paper provides a foundation for a companion paper in which we embed the model grids we compute here within a population synthesis code that enables us to compute the integrated line emission from galactic populations of H II regions.

  2. The structure of the broad-line region in the Seyfert galaxy Markarian 590

    NASA Technical Reports Server (NTRS)

    Peterson, Bradley M.; Ali, Babar; Horne, Keith; Bertram, Ray; Lame, Nancy J.; Pogge, Richard W.; Wagner, R. M.

    1993-01-01

    We have undertaken a nine-month study of continuum and emission-line variability in the Seyfert galaxy Mrk 590 in order to determine the structure of the broad-line region. The H-beta variations are found to lag behind those of the optical continuum by about 19 days. We apply a maximum entropy method to solve for the transfer function which relates the line and continuum variability. This analysis suggests that there is a deficit of emission-line response due to gas along the line of sight to the continuum source, as in the case of NGC 5548, although these data do not allow us to reject with confidence models with significant line-of-sight response. We also show that the H-beta line variability is apparently confined to the core of the emission line, as suggested previously by Ferland, Korista, and Peterson (1990).

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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 Hα and Hβ 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 λ4686 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

  4. The Structure of the Broad-Line Region in Well-Studied AGNs

    NASA Technical Reports Server (NTRS)

    Peterson, Bradley M.; Ferland, Gary J.

    1997-01-01

    Large amounts of high quality UV and optical data have been obtained in massive multi-wavelength monitoring campaigns on a small number of active galactic nuclei, and these data are changing our understanding of the central engines in these sources in a fundamental way. Preliminary analyses have shown that more comprehensive approaches will be necessary to make full use of these data. We propose to undertake a complete set of photoionization equilibrium calculations with a state-of-the-art computer code in order to determine the radial structure of the broad-line region in a way that is consistent with the emission-line fluxes, profiles, and transfer functions.

  5. A study of the structure and kinematics of the narrow-line region in Seyfert galaxies

    SciTech Connect

    Veilleux, S.

    1989-01-01

    The results of a high resolution study of the narrow emission line profiles of 16 Seyfert galaxies are presented. It is shown that the line profile parameters published in earlier low resolution studies are sometimes strongly influenced by resolution effects. In spite of these important systematic errors, many of the results derived from low resolution data are confirmed in the high resolution data. The narrow line profiles of Seyfert galaxies have a stronger base relative to core than a Gaussian. Most of the emission lines present a blueward asymmetry in the lower portion of their profile. In some galaxies, the line widths and/or line asymmetries are correlated with the ionization potential and/or critical density of the lines. There is a weak correlation between the line asymmetry and the dust content of the narrow line region (NLR). The large scatter in this relation, the absence of a similar correlation in Seyfert 1 to 1.5 galaxies, and the presence of a blue asymmetry in galaxies with dustfree line-emitting regions suggest that dust obscuration is not the only mechanism responsible for the line asymmetry in active galaxies. An optically-thick disk close to the nucleus is proposed as the other source of line asymmetry. An important result is that the host galaxy is probably playing a role in the kinematics of some of the gas in the NLR. A multicomponent model of the NLR is proposed to explain these results.

  6. The Broad-Line Region and Dust Torus Structure of Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Pozo Nuñez, Francisco

    2014-06-01

    I present the results from optical and infrared multi-month monitoring campaigns at the Universitätssternwarte Bochum (USB) in Chile to explore the structure of the central engine in active galactic nuclei (AGN). I apply and test photometric reverberation mapping (PRM) for measuring the time delay between variations in the continuum and Hbeta, Halpha emission lines. This time delay is used to infer the size of the broad-line region (BLR) for three Seyfert 1 galaxies. I place the results in context of the known BLR size luminosity relationship from spectroscopic reverberation mapping (SRM) and discuss its potential application to constrain cosmological parameters. The BLR size and the velocity dispersion of the emission line are used to calculate the virial mass of the supermassive black hole (SMBH). Through the direct modelling of PRM data, I infer the geometry type of the BLR allowing the determination of the geometry scaling factor used to constrain the real black hole mass. I find strong evidence for a disk-like BLR geometry. If this result holds for Seyfert galaxies in general, then the determination of the geometry scaling factor and the black hole mass can be remarkably improved. I discuss deviations of Seyfert-1 galaxies from the SMBH-bulge velocity dispersion relation MBH - sigma* for quiescent galaxies. Finally, I perform dust-reverberation mapping to determine the dust-torus size for the Seyfert 1 galaxy WPVS48. The light curves in the optical and near-infrared revealed unexpected variations which allow to solve an old puzzle on the geometry of the dusttorus.

  7. A study of the structure and kinematics of the narrow-line region in Seyfert galaxies. III. Individual objects

    SciTech Connect

    Veilleux, S. )

    1991-03-01

    An individual analysis is presented of the narrow-line profiles of 16 Seyfert galaxies. Substructure is observed in all but one of the sample objects. A direct relationship between the radio structure and these emission-line components is proposed in about half of the objects. The emission-line components generally have flux ratios which are quite similar to the rest of the narrow-line gas. These results suggest that the radio-emitting plasma strongly affects the kinematics of the thermal gas of the narrow-line region (NLR), but not its ionization state. Evidence for ionization/density stratification of the gas in the NLR is found in 4(ionization)/5(density) of the 11 objects for which a multispecies analysis is possible. The stronger cases of stratification are found in the objects whose emission lines present a minimum of profile substructure. A multicomponent model of the NLR is proposed to explain the results of this paper and previous ones. 192 refs.

  8. Two-component Structure of the Hβ Broad-line Region in Quasars. I. Evidence from Spectral Principal Component Analysis

    NASA Astrophysics Data System (ADS)

    Hu, Chen; Wang, Jian-Min; Ho, Luis C.; Ferland, Gary J.; Baldwin, Jack A.; Wang, Ye

    2012-12-01

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

  9. Albumin and alpha-fetoprotein gene transcription in rat hepatoma cell lines is correlated with specific DNA hypomethylation and altered chromatin structure in the 5' region.

    PubMed Central

    Tratner, I; Nahon, J L; Sala-Trepat, J M; Venetianer, A

    1987-01-01

    We examined DNA methylation and DNase I hypersensitivity of the alpha-fetoprotein (AFP) and albumin gene region in hepatoma cell lines which showed drastic differences in the level of expression of these genes. We assayed for methylation of the CCGG sequences by using the restriction enzyme isoschizomers HpaII and MspI. We found two methylation sites located in the 5' region of the AFP gene and one in exon 1 of the albumin gene for which hypomethylation is correlated with gene expression. Another such site, located about 4,000 base pairs upstream from the AFP gene, seems to be correlated with the tissue specificity of the cells. DNase I-hypersensitive sites were mapped by using the indirect end-labeling technique with cloned genomic DNA probes. Three tissue-specific DNase I-hypersensitive sites were mapped in the 5' flanking region of the AFP gene when this gene was transcribed. Similarly, three tissue-specific DNase I-hypersensitive sites were detected upstream from the albumin gene in producing cell lines. In both cases, the most distal sites were maintained after cessation of gene activity and appear to be correlated with the potential expression of the gene. Interestingly, specific methylation sites are localized in the same DNA region as DNase I hypersensitive sites. This suggests that specific alterations of chromatin structure and changes in methylation pattern occur in specific critical regulatory regions upstream from the albumin and AFP genes in rat hepatoma cell lines. Images PMID:2439898

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

    NASA Astrophysics Data System (ADS)

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

    2011-04-01

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

  11. Observations of the infrared fine-structure lines of S III at 18.71 and 33.47 microns in four H II regions

    NASA Technical Reports Server (NTRS)

    Herter, T.; Briotta, D. A., Jr.; Gull, G. E.; Shure, M. A.; Houck, J. R.

    1982-01-01

    Infrared fine-structure lines provide a particularly useful probe of ionized nebulae. The present investigation is concerned with measurements of the forbidden S III lines at 18.71 and 33.47 micrometers for four H II regions, S158A, S158G, G75.84+0.4, and W3 IRS 1. These lines are used to estimate densities, and comparisons are made with rms densities determined from radio observations to evaluate the importance of clumping. For the case of the optical H II region S158A, comparisons are made with both optical and forbidden O III line determinations of the density. The reported observations were made using a dual-grating, liquid-helium-cooled spectrometer containing a three-element Si:Sb detector array and a three-element Ge:Ga detector array. It is found that clumping is important in the cases of G75.84+0.4, W3 IRS 1, and M42. These three H II regions have filling factors of 0.024, 0.09, and 0.03, respectively.

  12. Structuring a service line.

    PubMed

    Zablocki, E

    1997-05-01

    In 1993, Community Hospitals Indianapolis created 10 service lines--each unique to the needs of the patients it serves. Two service line leaders talk about the factors critical to successful restructuring, the working relationships established, and the importance of clear communication to ensure understanding and get buy-in to the process. PMID:10167712

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

    SciTech Connect

    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.; Horne, Keith; Bentz, M. C.; Denney, K. D.; Siverd, R.; Sergeev, S. G.; Borman, G. A.; Bord, D. J.; Che, X.; and others

    2013-02-10

    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.

  14. EUV Spectral Line Formation and the Temperature Structure of Active Region Fan Loops: Observations with Hinode/EIS and SDO/AIA

    NASA Astrophysics Data System (ADS)

    Brooks, David H.; Warren, Harry P.; Young, Peter R.

    2011-04-01

    With the aim of studying active region fan loops using observations from the Hinode EUV Imaging Spectrometer (EIS) and Solar Dynamics Observatory Atmospheric Imaging Assembly (AIA), we investigate a number of inconsistencies in modeling the absolute intensities of Fe VIII and Si VII lines, and address why spectroheliograms formed from these lines look very similar despite the fact that ionization equilibrium calculations suggest that they have significantly different formation temperatures: log(Te /K) = 5.6 and 5.8, respectively. It is important to resolve these issues because confidence has been undermined in their use for differential emission measure (DEM) analysis, and Fe VIII is the main contributor to the AIA 131 Å channel at low temperatures. Furthermore, the strong Fe VIII 185.213 Å and Si VII 275.368 Å lines are the best EIS lines to use for velocity studies in the transition region, and for assigning the correct temperature to velocity measurements in the fans. We find that the Fe VIII 185.213 Å line is particularly sensitive to the slope of the DEM, leading to disproportionate changes in its effective formation temperature. If the DEM has a steep gradient in the log(Te /K) = 5.6-5.8 temperature range, or is strongly peaked, Fe VIII 185.213 Å and Si VII 275.368 Å will be formed at the same temperature. We show that this effect explains the similarity of these images in the fans. Furthermore, we show that the most recent ionization balance compilations resolve the discrepancies in absolute intensities. With these difficulties overcome, we combine EIS and AIA data to determine the temperature structure of a number of fan loops and find that they have peak temperatures of 0.8-1.2 MK. The EIS data indicate that the temperature distribution has a finite (but narrow) width < log (σ_{T_e}/K) = 5.5 which, in one detailed case, is found to broaden substantially toward the loop base. AIA and EIS yield similar results on the temperature, emission measure

  15. EUV SPECTRAL LINE FORMATION AND THE TEMPERATURE STRUCTURE OF ACTIVE REGION FAN LOOPS: OBSERVATIONS WITH HINODE/EIS AND SDO/AIA

    SciTech Connect

    Brooks, David H.; Young, Peter R.; Warren, Harry P.

    2011-04-01

    With the aim of studying active region fan loops using observations from the Hinode EUV Imaging Spectrometer (EIS) and Solar Dynamics Observatory Atmospheric Imaging Assembly (AIA), we investigate a number of inconsistencies in modeling the absolute intensities of Fe VIII and Si VII lines, and address why spectroheliograms formed from these lines look very similar despite the fact that ionization equilibrium calculations suggest that they have significantly different formation temperatures: log(T{sub e} /K) = 5.6 and 5.8, respectively. It is important to resolve these issues because confidence has been undermined in their use for differential emission measure (DEM) analysis, and Fe VIII is the main contributor to the AIA 131 A channel at low temperatures. Furthermore, the strong Fe VIII 185.213 A and Si VII 275.368 A lines are the best EIS lines to use for velocity studies in the transition region, and for assigning the correct temperature to velocity measurements in the fans. We find that the Fe VIII 185.213 A line is particularly sensitive to the slope of the DEM, leading to disproportionate changes in its effective formation temperature. If the DEM has a steep gradient in the log(T{sub e} /K) = 5.6-5.8 temperature range, or is strongly peaked, Fe VIII 185.213 A and Si VII 275.368 A will be formed at the same temperature. We show that this effect explains the similarity of these images in the fans. Furthermore, we show that the most recent ionization balance compilations resolve the discrepancies in absolute intensities. With these difficulties overcome, we combine EIS and AIA data to determine the temperature structure of a number of fan loops and find that they have peak temperatures of 0.8-1.2 MK. The EIS data indicate that the temperature distribution has a finite (but narrow) width < log ({sigma}{sub Te}/K) = 5.5 which, in one detailed case, is found to broaden substantially toward the loop base. AIA and EIS yield similar results on the temperature, emission

  16. A Multi-Scale Continuum and Line Exploration of the Most Luminous Star Formation Region in the Milky Way. I. The Mass Structure of the Giant Molecular Cloud.

    NASA Astrophysics Data System (ADS)

    Galvan-Madrid, R.; Liu, H. B.; Zhang, Z.-Y.; Pineda, J. E.; Peng, T.-C.; Zhang, Q.; Keto, E. R.; Ho, P. T. P.; Rodriguez, L. F.; Zapata, L.; Peters, T.; De Pree, C. G.

    2013-07-01

    The Multi-Scale Continuum and Line Exploration of W49 (MUSCLE W49) is a comprehensive gas and dust survey of the parental giant molecular cloud (GMC) of W49A, the most luminous (L~10^7.2 Lsun) star-formation region in the Milky Way. The project has multiple components that cover the entire GMC at different scales and angular resolutions, from 0.1 to 100 pc. We present a new all-configuration SMA mosaic of the central 10 pc (known as W49N), plus PMO mapping of the full GMC up to scales of 110 pc. We derive the mass structure of the GMC at all scales, revealing that the central ~0.1% of the volume, which contains ~20% of the total GMC mass, is forming a system of young massive clusters (YMCs). We compare our results with other possible sites of YMC formation in the Galaxy.

  17. A bayesian approach to estimate the size and structure of the broad-line region in active galactic nuclei using reverberation mapping data

    SciTech Connect

    Li, Yan-Rong; Wang, Jian-Min; Du, Pu; Ho, Luis C.; Bai, Jin-Ming

    2013-12-20

    This is the first paper in a series devoted to the systematic study of the size and structure of the broad-line region (BLR) in active galactic nuclei (AGNs) using reverberation mapping (RM) data. We employ a recently developed Bayesian approach that statistically describes the variability as a damped random walk process and delineates the BLR structure using a flexible disk geometry that can account for a variety of shapes, including disks, rings, shells, and spheres. We allow for the possibility that the line emission may respond non-linearly to the continuum, and we detrend the light curves when there is clear evidence for secular variation. We use a Markov Chain Monte Carlo implementation based on Bayesian statistics to recover the parameters and uncertainties for the BLR model. The corresponding transfer function is obtained self-consistently. We tentatively constrain the virial factor used to estimate black hole masses; more accurate determinations will have to await velocity-resolved RM data. Application of our method to RM data with Hβ monitoring for about 40 objects shows that the assumed BLR geometry can reproduce quite well the observed emission-line fluxes from the continuum light curves. We find that the Hβ BLR sizes obtained from our method are on average ∼20% larger than those derived from the traditional cross-correlation method. Nevertheless, we still find a tight BLR size-luminosity relation with a slope of α = 0.55 ± 0.03 and an intrinsic scatter of ∼0.18 dex. In particular, we demonstrate that our approach yields appropriate BLR sizes for some objects (such as Mrk 142 and PG 2130+099) where traditional methods previously encountered difficulties.

  18. Molecular Hydrogen Line Emission from Photodissociation Regions

    NASA Astrophysics Data System (ADS)

    Chrysostomou, Antonio

    1993-01-01

    The work presented in this thesis is dedicated to the study of the physical properties of photodissociation regions (PDRs), the surface layers of molecular clouds which are irradiated by ultraviolet radiation. The structure of PDRs is investigated with the development of an anlytical model which incorporates the essential heating and cooling mechanisms in a PDR. The main parameters in the model are the density and the incident ulttraviolet radiation field (G0) impinging on the surface which dissociates the molecules in the PDR. It is demonstrated that when the ratio (n / G0) is high (> 100 cm-3) the attenuation of ultraviolet photons is dominated by H2 self shielding, which brings the Hi/H2 transition zone close to the surface of the cloud (Av < 1). When the ratio is of order unity then the attenuation of ultraviolet photons is dominated by dust grains in the PDR. In this case, the Hi / H2 transition zone occurs at a depth of Av ~2-3. Images of the PDR in the northern bar of M17 show that there is a spatial coincidence, accurate to ~1 arcsec, of the H2 and 3.28 micron emission regions (the 3.28 micron emission being a tracer of the hot edge of the PDR delineated by the Hii / Hi transition) placing a lower limit to the density in the clumps of 105 cm-3. This coincidence is also observed in other PDR sources (eg. NGC 2023) and can be readily explained if the sources are clumpy. It is not clear in the northern bar of M17, where G0 ~104, whether shielding by dust or H2 molecules is dominated the attenuation of ultraviolet photons. A uniform, high density PDR model is sufficient to reproduce the observed H2 line intensity, however the images clearly reveal structures at the 2 arcsec level suggesting that a clumpy model is a realistic solution. Long slit K band spectroscopy measurements were taken in the northern bar of M17, where up to 16 H2 lines were identified. Analysis of the data suggests that the emission can only be explained if the H2 molecules are being excited

  19. Carbon recombination lines as a diagnostic of photodissociation regions

    NASA Technical Reports Server (NTRS)

    Natta, A.; Walmsley, C. M.; Tielens, A. G. G. M.

    1994-01-01

    We have observed the C91 alpha radio recombination line toward the Orion H II region. This narrow (approximately 3-5 km per sec full width at half maximum (FWHM)) line is spatially very extended (approximately 8 arcmin or 1 pc). These charateristics compare well with the observed characteristics of the C II fine structure line at 158 microns. Thus, the C91 alpha line originates in the predominantly neutral photodissociation regions separating the H II region from the molecular cloud. We have developed theoretical models for the C II radio recombination lines from photodissociation regions. The results show that the I(C91 alpha)/I(C158) intensity ratio is a sensitive function of the temperature and density of the emitting gas. We have also extended theoretical models for photodissociation regions to include the C II recombination lines. Comparison with these models show that, in the central portion of the Orion region, the C91 alpha line originates in dense (10(exp 6) per cu cm), warm (500-1000 K) gas. Even at large projected distances (approximately 1 pc), the inferred density is still high (10(exp 5) per cu cm) and implies extremely high thermal pressures. As in the case of the (C II) 158 microns line, the large extent of the C91 alpha line shows that (FUV) photons can penetrate to large distances from the illuminating source. The decline of the intensity of the incident radiation field with distance from Theta(sup 1) C seems to be dominated by geometrical dilution, rather than dust extinction. Finally, we have used our models to calculate the intensity of the 9850 A recombination line of C II. The physical conditions inferred from this line are in good agreement with those determined from the radio recombination and the far-infrared fine-structure lines. We show that the ratio of the 9850 A to the C91 alpha lines is a very good probe of very high density clumps.

  20. Giant Broad Line Regions in Dwarf Seyferts

    NASA Astrophysics Data System (ADS)

    Devereux, Nicholas A.

    2016-01-01

    High angular resolution spectroscopy obtained with the Hubble Space Telescope has revealed a remarkable population of galaxies hosting dwarf Seyfert nuclei with an unusually large broad-line region (BLR). These objects are remarkable for two reasons. Firstly, the size of the BLR can, in some cases, rival those seen in the most luminous quasars. Secondly, the size of the BLR is not correlated with the central continuum luminosity, an observation that distinguishes them from their reverberating counterparts. Collectively, these early results suggest that non-reverberating dwarf Seyferts are a heterogeneous group and not simply scaled versions of each other. Careful inspection reveals broad H Balmer emission lines with single peaks, double peaks, and a combination of the two, suggesting that the broad emission lines are produced in kinematically distinct regions centered on the black hole (BH). Because the gravitational field strength is already known for these objects, by virtue of knowing their BH mass, the relationship between velocity and radius may be established, given a kinematic model for the BLR gas. In this way, one can determine the inner and outer radii of the BLRs by modeling the shape of their broad emission line profiles. In the present contribution, high quality spectra obtained with the Space Telescope Imaging Spectrograph are used to constrain the size of the BLR in the dwarf Seyfert nuclei of M81, NGC 3998, NGC 4203, NGC 3227, NGC 4051, and NGC 3516.

  1. Giant Broad Line Regions in Dwarf Seyferts

    NASA Astrophysics Data System (ADS)

    Devereux, Nick

    2015-12-01

    High angular resolution spectroscopy obtained with the Hubble Space Telescope (HST) has revealed a remarkable population of galaxies hosting dwarf Seyfert nuclei with an unusually large broad-line region (BLR). These objects are remarkable for two reasons. Firstly, the size of the BLR can, in some cases, rival those seen in the most luminous quasars. Secondly, the size of the BLR is not correlated with the central continuum luminosity, an observation that distinguishes them from their reverberating counterparts. Collectively, these early results suggest that non-reverberating dwarf Seyferts are a heterogeneous group, and not simply scaled versions of each other. Careful inspection reveals broad H Balmer emission lines with single peaks, double peaks, and a combination of the two, suggesting that the broad emission lines are produced in kinematically distinct regions centered on the black hole (BH). Because the gravitational field strength is already known for these objects, by virtue of knowing their BH mass, the relationship between velocity and radius may be established, given a kinematic model for the BLR gas. In this way, one can determine the inner and outer radii of the BLRs by modeling the shape of their broad emission line profiles. In the present contribution, high quality spectra obtained with the Space Telescope Imaging Spectrograph (STIS) are used to constrain the size of the BLR in the dwarf Seyfert nuclei of M81, NGC 3998, NGC 4203, NGC 3227, NGC 4051 and NGC 3516.

  2. VLT/ISAAC spectra of the Hβ region in intermediate-redshift quasars. III. Hβ broad-line profile analysis and inferences about BLR structure

    NASA Astrophysics Data System (ADS)

    Marziani, P.; Sulentic, J. W.; Stirpe, G. M.; Zamfir, S.; Calvani, M.

    2009-02-01

    Aims: We present new VLT ISAAC spectra for 30 quasars, which we combine with previous data to yield a sample of 53 intermediate-redshift (z ≈ 0.9-3.0) sources. The sample is used to explore properties of prominent lines in the hβ spectral region of these very luminous quasars. Methods: We compare this data with two large low-redshift (z < 0.8) samples in a search for trends over almost 6dex in source luminosity. Results: We find two major trends: (1) a systematic increase in minimum FWHM hβ with luminosity (discussed in a previous paper). This lower FWHM envelope is best fit by assuming that the narrowest sources radiate near the Eddington limit, show line emission from a virialized cloud distribution, and obey a well-defined broad line region size vs. luminosity relation. (2) A systematic decrease in equivalent width of [oiii]λλ4959, 5007 (from W ≈ 15 to ~1 Å) with increasing source bolometric luminosity (from log L_bol ≈ 43 to log L_bol ≈ 49). Other identified trends require differntiating between so-called Population A and Bsources. We generate median composite spectra in six luminosity bins to maximize S/N. Population A sources show reasonably symmetric Lorentzian hβ profiles at all luminosities, while Pop. B sources require two component fits involving an unshifted broad and a redshifted very broad component. Very broad hβ increases in strength with increasing log L_bol, while the broad component remains constant, resulting in an apparent “Baldwin effect” with equivalent width decreasing from W ~ 80 to ~20 Å over our sample luminosity range. The roughly constant equivalent width shown by the hβ very broad component implies production in optically-thick, photoionized gas. The onset of the redshifted very broad component appears to be a critical change that occurs near the Pop. A-B boundary at FWHM hβ ≈ 4000 km s-1, which we relate to a critical Eddington ratio (≈ 0.2±0.1). Based on observations made with ESO Telescopes at the Paranal

  3. Magnetohydrodynamic stability of broad line region clouds

    NASA Astrophysics Data System (ADS)

    Krause, Martin; Schartmann, Marc; Burkert, Andreas

    2012-10-01

    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.

  4. Changes in sinuosities of the rivers at geological structural lines in the Pannonian Basin - Mosaics to the neotectonic image of the region

    NASA Astrophysics Data System (ADS)

    Petrovszki, Judit

    2010-05-01

    In the central, flat area of the Pannonian Basin, there are just few topographic features for neotectonic investigations. However, a lot of meandering rivers flow here, and it is possible to reconstruct their natural, pre-regulation planforms. Using the map sheets of the Second Military Survey of the Habsburg Empire (mid-19th century; Timár et al., 2006), I digitized the meandering rivers on this area. Sinuosities at different sample section lengths were computed in a GIS environment, providing so-called 'sinuosity-spectra' (van Balen et al., 2008) for each point of the analyzed channels. The channel sinuosity of this river systems are analyzed in order to draw conclusions on the neotectonic activity of the Great Hungarian Plain and the other flat areas of the Pannonian Basin. Several points of sinuosity change were identified. To prove, that these are of neotectonic origin, seismic sections crossing the study area, were also analyzed as well as the geodinamical map of the area (Horváth et al., 2006). High sinuosity variations (low to high or high to low), spatially correlated to linear features identified in seismic survey sections, indicating their neotectonic activity (after Ouchi, 1985). We can see two significante sinuosity changes on the Hron/Garam River (Slovakia), one at Tekov and the one at Kéménd. There are faults on the neotectonic map at these points, crossing the river - they are the possible causes of the increasing of the sinuosity. The vertical activity of these structural lines is verified by the sinuosity changes. At the Maros/Mureş River (Romania/Hungary), a significant sinuosity change can also be identified near to the town of Aiud, where the phenomene is just the opposite like in the Hron/Garam river. There is a fault on the neotectonic map crossing the river. Upstream of the river has higher sinuosity values, and after crossing the fault, it decresed. Here also the fault caused the sinuosity changing, so this fault is also an active one

  5. DUSTY STRUCTURE AROUND TYPE-I ACTIVE GALACTIC NUCLEI: CLUMPY TORUS NARROW-LINE REGION AND NEAR-NUCLEUS HOT DUST

    SciTech Connect

    Mor, Rivay; Netzer, Hagai; Elitzur, Moshe

    2009-11-01

    We fitted Spitzer/IRS approx 2-35 mum spectra of 26 luminous quasi-stellar objects in an attempt to define the main emission components. Our model has three major components: a clumpy torus, dusty narrow-line region (NLR) clouds, and a blackbody-like dust. The models utilize the clumpy torus of Nenkova et al. and are the first to allow its consistent check in type-I active galactic nuclei (AGNs). Single torus models and combined torus-NLR models fail to fit the spectra of most sources, but three-component models adequately fit the spectra of all sources. We present torus inclination, cloud distribution, covering factor, and torus mass for all sources and compare them with bolometric luminosity, black hole mass, and accretion rate. The torus mass is found to be correlated with the bolometric luminosity of the sources. Torus-covering factor may also be (anti-)correlated, if some possibly anomalous points are omitted. We find that a substantial amount of the approx2-7 mum radiation originates from a hot dust component, which is likely situated in the innermost part of the torus. The luminosity radiated by this component and its covering factor are comparable to those of the torus. We quantify the emission by the NLR clouds and estimate their distance from the center. The distances are approx700 times larger than the dust sublimation radius, and the NLR-covering factor is about 0.07. The total covering factor by all components is in good agreement with the known AGN type-I:type-II ratio.

  6. Detecting pore-lining regions in transmembrane protein sequences

    PubMed Central

    2012-01-01

    Background Alpha-helical transmembrane channel and transporter proteins play vital roles in a diverse range of essential biological processes and are crucial in facilitating the passage of ions and molecules across the lipid bilayer. However, the experimental difficulties associated with obtaining high quality crystals has led to their significant under-representation in structural databases. Computational methods that can identify structural features from sequence alone are therefore of high importance. Results We present a method capable of automatically identifying pore-lining regions in transmembrane proteins from sequence information alone, which can then be used to determine the pore stoichiometry. By labelling pore-lining residues in crystal structures using geometric criteria, we have trained a support vector machine classifier to predict the likelihood of a transmembrane helix being involved in pore formation. Results from testing this approach under stringent cross-validation indicate that prediction accuracy of 72% is possible, while a support vector regression model is able to predict the number of subunits participating in the pore with 62% accuracy. Conclusion To our knowledge, this is the first tool capable of identifying pore-lining regions in proteins and we present the results of applying it to a data set of sequences with available crystal structures. Our method provides a way to characterise pores in transmembrane proteins and may even provide a starting point for discovering novel routes of therapeutic intervention in a number of important diseases. This software is freely available as source code from: http://bioinf.cs.ucl.ac.uk/downloads/memsat-svm/. PMID:22805427

  7. Hyperfine structure analysis in the intense spectral lines of the neutral Cu atom falling in the 353-809 nm wavelength region using a Fourier transform spectrometer

    NASA Astrophysics Data System (ADS)

    Ankush, B. K.; Deo, M. N.

    2014-02-01

    Hyperfine structure analyses have been performed in the high-resolution spectrum of the neutral copper atom covering the wavelength region of 353-809 nm using Fourier transform spectroscopy. A DC discharge of natural copper produced in a liquid nitrogen cooled hollow cathode lamp used as a light source and a photomultiplier tube as well as Si photodiodes were employed as the light detectors. The hfs studies in 17 transitions of the neutral copper atom originating from 17 energy levels for 63Cu have been reported here. The present investigation has provided the magnetic dipole coupling constant A and electric quadrupole coupling constant B for the first time for the following 6 even-parity levels lying at 49,935, 49,942 cm-1, of 3d104d configuration, 52,848 cm-1 of 3d106 s configuration, 55,387, 55,391 cm-1 3d105d configuration and 71,978 cm-1 of 3d104s4d configuration. The sign convention of the previously-reported hfs A value amounting to 1920 MHz for the level at 44,963 cm-1 of 3d94s4p configuration has been revised to -1920 MHz. Measurements reported earlier of A and B hfs constants for the 11 odd-parity energy levels also have been confirmed.

  8. First structures on RyantoRainbow Line. Hframe structure on Line 1 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    First structures on Ryan-to-Rainbow Line. H-frame structure on Line 1 (right) has historic porcelain suspension insulators and H-frame structure on Line 2 (center) has two historic porcelain insulators and one modern non-ceramic insulator. View to north - Ryan Hydroelectric Facility, Ryan-to-Rainbow 100 kV Transmission Line, West bank of Missouri River, northeast of Great Falls, Great Falls, Cascade County, MT

  9. 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)

    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

    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.

  10. Fine-structure line deficit in S 140

    NASA Astrophysics Data System (ADS)

    Ossenkopf, V.; Koumpia, E.; Okada, Y.; Mookerjea, B.; van der Tak, F. F. S.; Simon, R.; Pütz, P.; Güsten, R.

    2015-08-01

    Aims: We try to understand the gas heating and cooling in the S 140 star-forming region by spatially and spectrally resolving the distribution of the main cooling lines with GREAT/SOFIA and combining our data with existing ground-based and Herschel observations that trace the energy input and the density and temperature structure of the source. Methods: We mapped the fine-structure lines of [O i] (63 μm) and [C ii] (158 μm) and the rotational transitions of CO 13-12 and 16-15 with GREAT/SOFIA and analyzed the spatial and velocity structure to assign the emission to individual heating sources. We measure the optical depth of the [C ii] line and perform radiative transfer computations for all observed transitions. By comparing the line intensities with the far-infrared continuum we can assess the total cooling budget and measure the gas heating efficiency. Results: The main emission of fine-structure lines in S 140 stems from a 8.3'' region close to the infrared source IRS 2 that is not prominent at any other wavelength. It can be explained by a photon-dominated region (PDR) structure around the embedded cluster if we assume that the [O i] line intensity is reduced by a factor of seven owing to self-absorption. The external cloud interface forms a second PDR at an inclination of 80-85 degrees illuminated by a UV field of 60 times the standard interstellar radiation field. The main radiation source in the cloud, IRS 1, is not prominent at all in the fine-structure lines. We measure line-to-continuum cooling ratios below 10-4, i.e. values lower than in any other Galactic source, actually matching the far-IR line deficit seen in ULIRGs. In particular, the low intensity of the [C ii] line can only be modeled by an extreme excitation gradient in the gas around IRS 1. We found no explanation for why IRS 1 shows no associated fine-structure line peak, while IRS 2 does. Conclusions: The inner part of S 140 mimics the far-IR line deficit in ULIRGs thereby providing a

  11. Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. 6: Variability of NGC 3783 from ground-based data

    NASA Technical Reports Server (NTRS)

    Stirpe, G. M.; Winge, C.; Altieri, B.; Alloin, D.; Aguero, E. L.; Anupama, G. C.; Ashley, R.; Bertram, R.; Calderon, J. H.; Catchpole, R. M.

    1994-01-01

    The Seyfert 1 galaxy NGC 3783 was intensely monitored in several bands between 1991 December and 1992 August. This paper presents the results from the ground-based observations in the optical and near-IR bands, which complement the data set formed by the International Ultraviolet Explorer (IUE) spectra, discussed elsewhere. Spectroscopic and photometric data from several observatories were combined in order to obtain well-sampled light curves of the continuum and of H(beta). During the campaign the source underwent significant variability. The light curves of the optical continuum and of H(beta) display strong similarities to those obtained with the IUE. The near-IR flux did not vary significantly except for a slight increase at the end of the campaign. The cross-correlation analysis shows that the variations of the optical continuum have a lag of 1 day or less with respect to those of the UV continuum, with an uncertainty of is less than or equal to 4 days. The integrated flux of H(beta) varies with a delay of about 8 days. These results confirm that (1) the continuum variations occur simultaneously or with a very small lag across the entire UV-optical range, as in the Seyfert galaxy NGC 5548; and (2) the emission lines of NGC 3783 respond to ionizing continuum variations with less delay than those of NGC 5548. As observed in NGC 5548, the lag of H(beta) with respect to the continuum is greater than those of the high-ionization lines.

  12. Plasma simulations of emission line regions in high energy environments

    NASA Astrophysics Data System (ADS)

    Richardson, Chris T.

    This dissertation focuses on understanding two different, but in each case extreme, astrophysical environments: the Crab Nebula and emission line galaxies. These relatively local objects are well constrained by observations and are test cases of phenomena seen at high-z where detailed observations are rare. The tool used to study these objects is the plasma simulation code known as Cloudy. The introduction provides a brief summary of relevant physical concepts in nebular astrophysics and presents the basic features and assumptions of Cloudy. The first object investigated with Cloudy, the Crab Nebula, is a nearby supernova remnant that previously has been subject to photoionization modeling to reproduce the ionized emission seen in the nebula's filamentary structure. However, there are still several unanswered questions: (1) What excites the H2 emitting gas? (2) How much mass is in the molecular component? (3) How did the H2 form? (4) What is nature of the dust grains? A large suite of observations including long slit optical and NIR spectra over ionized, neutral and molecular gas in addition to HST and NIR ground based images constrain a particularly bright region of H2 emission, Knot 51, which exhibits a high excitation temperature of ˜3000 K. Simulations of K51 revealed that only a trace amount of H2 is needed to reproduce the observed emission and that H2 forms through an uncommon nebular process known as associative detachment. The final chapters of this dissertation focus on interpreting the narrow line region (NLR) in low-z emission line galaxies selected by a novel technique known as mean field independent component analysis (MFICA). A mixture of starlight and radiation from an AGN excites the gas present in galaxies. MFICA separates galaxies over a wide range of ionization into subsets of pure AGN and pure star forming galaxies allowing simulations to reveal the properties responsible for their observed variation in ionization. Emission line ratios can

  13. Fine Structure and Optical Depth in the Solar Transition Region

    NASA Astrophysics Data System (ADS)

    Plovanic, Jacob; Kankelborg, C. C.; Williamson, K.

    2011-05-01

    Unresolved fine structure in the solar transition region (TR) has long been inferred from measurements of density-sensitive line pairs showing low filling factor (< 0.01). Low filling factor models for the structure of the He II source region, however, have not been well studied. We propose a highly structured model of the lower atmosphere in which He II is formed at low filling factors, leading to high emission measure and an optically thin He II line. This transparent TR material is juxtaposed with absorbing chromospheric structures, leading to the nearly uniform center to limb behavior of the He II line as observed.

  14. 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)

    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

    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

  15. Fine-structure infrared lines from the Cassiopeia A knots

    NASA Astrophysics Data System (ADS)

    Docenko, D.; Sunyaev, R. A.

    2010-01-01

    Aims: Archival observations of infrared fine-structure lines of the young Galactic supernova remnant Cassiopeia A allow us to test existing models and determine the physical parameters of various regions of the fast-moving knots, which are metal-dominated clouds of material ejected by the supernova explosion. Methods: The fluxes of far-infrared [O i] and [O iii] lines are extracted from previously unpublished archival ISO data. The archival Spitzer data are used to determine the fluxes of the O, Ne, Si, S, Ar, and Fe ion fine-structure lines originating in the fast-moving knots. The ratios of these line fluxes are used as plasma diagnostics. We also determine the infrared line flux ratios with respect to the optical [O iii] 5007 Å line in the knots with previously measured reddening. Additionally, we analyze several optical and near-infrared observations of the fast-moving knots to obtain clearer insight into the post-shock photoionized region structure. Results: We show that the infrared oxygen line flux predictions of all existing theoretical models are correct only to within a factor of a several. Comparison of the model predictions shows that to reproduce the observations it is essential to include the effects of the electron conductivity and dust. Detailed analysis of the diagnostic line flux ratios of various ions allows us to qualitatively confirm the general model of fast-moving knot emission and determine observationally for the first time the physical conditions in the photoionized region after the shock. We infer from the [O iii] line flux ratios that the pre-shock cloud densities are higher than assumed in existing theoretical models and most probably correspond to several hundred particles per cm3. We also determine the Cas A luminosity in the infrared continuum and lines. We show that accounting for the charge exchange processes in the post-shock photoionized region allows us to reproduce most of the relevant spectral line ratios even in the frame of

  16. What Quasars Really Look Like: Unification of the Emission and Absorption Line Regions

    NASA Technical Reports Server (NTRS)

    Elvis, Martin

    2000-01-01

    We propose a simple unifying structure for the inner regions of quasars and AGN. This empirically derived model links together the broad absorption line (BALS), the narrow UV/X-ray ionized absorbers, the BELR, and the 5 Compton scattering/fluorescing regions into a single structure. The model also suggests an alternative origin for the large-scale bi-conical outflows. Some other potential implications of this structure are discussed.

  17. Structure and form of grounding lines of modern ice sheets

    NASA Astrophysics Data System (ADS)

    Tinto, K. J.; Bell, R. E.; Cochran, J. R.; Boghosian, A.; Porter, D. F.

    2015-12-01

    The form of the bed at the grounding line of a glacier and the character of the underlying rock can be critical to the stability of the glacier. Aerogravity measurements offer a unique insight in to the character of the grounding line environment. By combining depth measurements from further onshore radar and geological information from magnetic surveys, gravity-based models can reveal both the depth and slope of the bed at the grounding line. Where bed elevation is known at the grounding line, gravity models can show the density structure of the underlying rock. Operation IceBridge has flown coincident radar, lidar, photography, gravity and magnetic airborne surveys along fjords and over ice shelves in both Greenland and Antarctica. Aerogravity measurements have been used extensively to model the bathymetry of the sea floor in front of the grounding line, and to identify the depth of the grounding line in areas where radar measurements have proven challenging. These models have also been used to reveal the range of conditions at present day grounding lines, as well as those experienced in the past and predicted for future grounding line positions. In some regions, we have identified low-density sediment accumulations, at both present day grounding lines and within fjords, that we interpret to be terminal moraines deposited by the glacier itself during hiatuses in retreat. In other regions, we find that the present day grounding line is stalled on a ridge of high-density rock. Ridges such as these remain in the same position through many cycles of advance and retreat of the glacier. Our synthesis of gravity data from a wide range of glacial environments can be used to identify likely drivers of change at the grounding line, whether this is the depth, the slope, or the geological character of the glacier bed.

  18. Neutral line chaos and phase space structure

    NASA Technical Reports Server (NTRS)

    Burkhart, Grant R.; Speiser, Theodore W.; Martin, Richard F., Jr.; Dusenbery, Paul B.

    1991-01-01

    Phase space structure and chaos near a neutral line are studied with numerical surface-of-section (SOS) techniques and analytic methods. Results are presented for a linear neutral line model with zero crosstail electric field. It was found that particle motion can be divided into three regimes dependening on the value of the conserved canonical momentum, Py, and the conserved Hamiltonian, h. The phase space structure, using Poincare SOS plots, is highly sensitive to bn = Bn/B0 variations, but not to h variations. It is verified that the slow motion preserves the action, Jz, as evaluated by Sonnerup (1971), when the period of the fast motion is smaller than the time scale of the slow motion. Results show that the phase space structure and particle chaos depend sensitively upon Py and bn, but are independent of h.

  19. SOLAR TRANSITION REGION LINES OBSERVED BY THE INTERFACE REGION IMAGING SPECTROGRAPH: DIAGNOSTICS FOR THE O IV AND Si IV LINES

    SciTech Connect

    Dudík, J.; Del Zanna, G.; Mason, H. E.; Dzifčáková, E.; Golub, L.

    2014-01-01

    The formation of the transition region O IV and Si IV lines observable by the Interface Region Imaging Spectrograph (IRIS) is investigated for both Maxwellian and non-Maxwellian conditions characterized by a κ-distribution exhibiting a high-energy tail. The Si IV lines are formed at lower temperatures than the O IV lines for all κ. In non-Maxwellian situations with lower κ, the contribution functions are shifted to lower temperatures. Combined with the slope of the differential emission measure, it is possible for the Si IV lines to be formed at very different regions of the solar transition region than the O IV lines; possibly close to the solar chromosphere. Such situations might be discernible by IRIS. It is found that photoexcitation can be important for the Si IV lines, but is negligible for the O IV lines. The usefulness of the O IV ratios for density diagnostics independently of κ is investigated and it is found that the O IV 1404.78 Å/1399.77 Å ratio provides a good density diagnostics except for very low T combined with extreme non-Maxwellian situations.

  20. Line Emission from Radiation-pressurized H II Regions. II. Dynamics and Population Synthesis

    NASA Astrophysics Data System (ADS)

    Verdolini, Silvia; Yeh, Sherry C. C.; Krumholz, Mark R.; Matzner, Christopher D.; Tielens, Alexander G. G. M.

    2013-05-01

    Optical and infrared emission lines from H II regions are an important diagnostic used to study galaxies, but interpretation of these lines requires significant modeling of both the internal structure and dynamical evolution of the emitting regions. Most of the models in common use today assume that H II region dynamics are dominated by the expansion of stellar wind bubbles, and have neglected the contribution of radiation pressure to the dynamics, and in some cases also to the internal structure. However, recent observations of nearby galaxies suggest that neither assumption is justified, motivating us to revisit the question of how H II region line emission depends on the physics of winds and radiation pressure. In a companion paper we construct models of single H II regions including and excluding radiation pressure and winds, and in this paper we describe a population synthesis code that uses these models to simulate galactic collections of H II regions with varying physical parameters. We show that the choice of physical parameters has significant effects on galactic emission line ratios, and that in some cases the line ratios can exceed previously claimed theoretical limits. Our results suggest that the recently reported offset in line ratio values between high-redshift star-forming galaxies and those in the local universe may be partially explained by the presence of large numbers of radiation-pressure-dominated H II regions within them.

  1. The 2mrad Crossing Angle Interaction Region and Extraction Line

    SciTech Connect

    Appleby, R.; U., Manchester; Angal-Kalinin, D.; Dadoun, O.; Bambade, P.; Parker, B.; Keller, L.; Moffeit, K.; Nosochkov, Y.; Seryi, A.; Spencer, C.; Carter, J.; Royal Holloway, U.of London; Napoly, O.; /DAPNIA, Saclay

    2006-07-12

    A complete optics design for the 2mrad crossing angle interaction region and extraction line was presented at Snowmass 2005. Since this time, the design task force has been working on developing and improving the performance of the extraction line. The work has focused on optimizing the final doublet parameters and on reducing the power losses resulting from the disrupted beam transport. In this paper, the most recent status of the 2mrad layout and the corresponding performance are presented.

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

    SciTech Connect

    Guerras, E.; Mediavilla, E.; Kochanek, C. S.; Munoz, J. A.; Falco, E.; Motta, V.

    2013-02-20

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

  3. The HST view of the innermost narrow line region

    NASA Astrophysics Data System (ADS)

    Balmaverde, Barbara; Capetti, Alessandro; Moisio, Daria; Baldi, Ranieri D.; Marconi, Alessandro

    2016-02-01

    We analyze the properties of the innermost narrow line region in a sample of low-luminosity AGN. We select 33 LINERs (bona fide AGN) and Seyfert galaxies from the optical spectroscopic Palomar survey observed by HST/STIS. We find that in LINERs the [ N II ] and [ O I ] lines are broader than the [ S II ] line and that the [ N II ] /[ S II ] flux ratio increases when moving from ground-based to HST spectra. This effect is more pronounced considering the wings of the lines. Our interpretation is that, as a result of superior HST spatial resolution, we isolate a compact region of dense ionized gas in LINERs, located at a typical distance of ~3 pc and with a gas density of ~104-105 cm-3, which we identify with the outer portion of the intermediate line region (ILR). Instead, we do not observe these kinds of effects in Seyferts; this may be the result of a stronger dilution from the NLR emission, since the HST slit maps a larger region in these sources. Alternatively, we argue that the innermost, higher density component of the ILR is only present in Seyferts, while it is truncated at larger radii because of the presence of the circumnuclear torus. The ILR is only visible in its entirety in LINERs because the obscuring torus is not present in these sources.

  4. The coronal field lines of an evolving bipolar magnetic region

    NASA Technical Reports Server (NTRS)

    Sheeley, N. R., Jr.

    1982-01-01

    A simple potential field model is presented to illustrate that loops of magnetic flux rise upward through the corona during the relatively short growth phase of a bipolar magnetic region but contract back to the sun's surface during the much longer decay phase of the photospheric region. To reconcile this behavior with the unidirectional, solar-wind-driven convection of flux outward from the sun, one must postulate the existence of an X-type neutral line in the middle corona where open field lines can be converted back to closed ones.

  5. Accretion disk wind in the AGN broad-line region: Spectroscopically resolved line profile variations in Mrk 110

    NASA Astrophysics Data System (ADS)

    Kollatschny, W.

    2003-08-01

    Detailed line profile variability studies of the narrow line Seyfert 1 galaxy Mrk 110 are presented. We obtained the spectra in a variability campaign carried out with the 9.2 m Hobby-Eberly Telescope at McDonald Observatory. The integrated Balmer and helium (He I, 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 Mrk 110. 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 Mrk 110. We determine a central black hole mass of M = 1.8x 107 Msun. Because of the poorly known inclination angle of the accretion disk this is a lower limit only. 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, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

  6. Impurity Line Emissions in VUV Region of TCABR Tokamak

    SciTech Connect

    Machida, M.; Daltrini, A. M.; Severo, J. H. F.; Nascimento, I. C.; Sanada, E. K.; Elizondo, J. I.; Kuznetsov, Y. K.; Galvao, R. M. O.

    2008-04-07

    Spectral emissions in the vacuum ultraviolet region from 50 nm to 320 nm have been measured on TCABR tokamak using an one meter VUV spectrometer and a MCP coupled to a CCD detector. Among the 98 emissions classified, 37 are from first order diffraction, 29 are from second order, 24 are from third order, 7 from fourth order, and one from fifth order diffraction. Main impurity lines are OII to OVII, CII to CIV, NIII to N V, FVII, besides working gas plasma hydrogen Lyman lines.

  7. Investigation of ionization mechanism of extended narrow line region.

    NASA Astrophysics Data System (ADS)

    Hashimoto, T. H.; Iye, M. I.; Aoki, K. A.

    2006-08-01

    The narrow line regions of active galaxies have the potential to provide key information about the nature of the central energy sources, the triggering and fueling of the activity, and the dynamical and/or chemical evolution of the narrow line region (NLR). However, if we are to use them in this way, it is crucial to understand the dominant physical mechanism of emission line region. Since Dopita et al.1995,1996 suggested that their radiative shock model is capable of explaining to some extent the spectrum of Seyfert 2 galaxies, detailed observations of individual NLR or extended narrow line region (ENLR) have been performed to clarify the actual ionization mechanism for individual object. It is probably fair to say that at present time, although individual studies may favor gas models photoionized by nonthermal power law photons or other ionization scenario, no clear-cut answer has yet emerged. For the purpose of investigating the importance of shock ionization around NLR we performed optical long-slit spectroscopic observation of Seyfert 2 galaxy, NGC7319, using Subaru telescope during guaranteed time of Faint Object Camera And Spectrograph (FOCAS). We confirmed that NGC7319 has the ENLR (~4kpc) with relatively good alignment with radio components and found the distribution of observed regions in the "diagnostic diagrams"(line ratio versus line ratio plot) are approximately consistent with radiative shock ionization models which assumed about shock front velocity of 500km/s. In addition we discovered the clear anti-corelation between the indicators of gas excitation ([OIII]5007/ Hbeta and [SII](6716+6731)/Halpha) and velocity dispersion over whole observed ENLR. Any other photoionization model could not explain gas kinematics-excitation relation and this anti-corelation is strong evidence of radiative shock ionization, which is probably induced by interaction between jet plasma and NLR clouds. The evidence of the importance of jet-induced shock ionization even

  8. Cloudy 94 and Applications to Quasar Emission Line Regions

    NASA Technical Reports Server (NTRS)

    Ferland, Gary J.

    2000-01-01

    This review discusses the most recent developments of the plasma simulation code Cloudy and its application to the, emission-line regions of quasars. The longterm goal is to develop the tools needed to determine the chemical composition of the emitting gas and the luminosity of the central engine for any emission line source. Emission lines and the underlying thermal continuum are formed in plasmas that are far from thermodynamic equilibrium. Their thermal and ionization states are the result of a balance of a vast set of microphysical processes. Once produced, radiation must, propagate out of the (usually) optically thick source. No analytic solutions are possible, and recourse to numerical simulations is necessary. I am developing the large-scale plasma simulation code Cloudy as an investigative tool for this work, much as an observer might build a spectrometer. This review describes the current version of Cloudy, version 94. It describes improvements made since the, release of the previous version, C90. The major recent, application has been the development of the "Locally Optimally-Emitting Cloud" (LOC) model of AGN emission line regions. Powerful selection effects, introduced by the atomic physics and line formation process, permit individual lines to form most efficiently only near certain selected parameters. These selection effects, together with the presence of gas with a wide range of conditions, are enough to reproduce the spectrum of a typical quasar with little dependence on details. The spectrum actually carries little information to the identity of the emitters. I view this as a major step forward since it provides a method to handle accidental details at the source, so that we can concentrate on essential information such as the luminosity or chemical composition of the quasar.

  9. MUSCLE W49: A multi-scale continuum and line exploration of the most luminous star formation region in the Milky Way. I. Data and the mass structure of the giant molecular cloud

    SciTech Connect

    Galván-Madrid, R.; Pineda, J. E.; Peng, T.-C.; Liu, H. B.; Ho, P. T. P.; Zhang, Z.-Y.; Zhang, Q.; Keto, E. R.; Rodríguez, L. F.; Zapata, L.; Peters, T.; De Pree, C. G.

    2013-12-20

    The Multi-scale Continuum and Line Exploration of W49 is a comprehensive gas and dust survey of the giant molecular cloud (GMC) of W49A, the most luminous star-formation region in the Milky Way. The project covers, for the first time, the entire GMC at different scales and angular resolutions. In this paper, we present (1) an all-configuration Submillimeter Array mosaic in the 230 GHz (1.3 mm) band covering the central ∼3' × 3' (∼10 pc, known as W49N), where most of the embedded massive stars reside and (2) Purple Mountain Observatory 14 m telescope observations in the 90 GHz band, covering the entire GMC with maps of up to ∼35' × 35' in size, or ∼113 pc. We also make use of archival data from the Very Large Array, JCMT-SCUBA, the IRAM 30 m telescope, and the Caltech Submillimeter Observatory BOLOCAM Galactic Plane Survey. We derive the basic physical parameters of the GMC at all scales. Our main findings are as follows. (1) The W49 GMC is one of the most massive in the Galaxy, with a total mass M {sub gas} ∼ 1.1 × 10{sup 6} M {sub ☉} within a radius of 60 pc. Within a radius of 6 pc, the total gas mass is M {sub gas} ∼ 2 × 10{sup 5} M {sub ☉}. At these scales, only ∼1% of the material is photoionized. The mass reservoir is sufficient to form several young massive clusters (YMCs) as massive as a globular cluster. (2) The mass of the GMC is distributed in a hierarchical network of filaments. At scales <10 pc, a triple, centrally condensed structure peaks toward the ring of HC H II regions in W49N. This structure extends to scales from ∼10 to 100 pc through filaments that radially converge toward W49N and its less-prominent neighbor W49S. The W49A starburst most likely formed from global gravitational contraction with localized collapse in a 'hub-filament' geometry. (3) Currently, feedback from the central YMCs (with a present mass M {sub cl} ≳ 5 × 10{sup 4} M {sub ☉}) is still not enough to entirely disrupt the GMC, but further stellar

  10. MUSCLE W49: A Multi-Scale Continuum and Line Exploration of the Most Luminous Star Formation Region in the Milky Way. I. Data and the Mass Structure of the Giant Molecular Cloud

    NASA Astrophysics Data System (ADS)

    Galván-Madrid, R.; Liu, H. B.; Zhang, Z.-Y.; Pineda, J. E.; Peng, T.-C.; Zhang, Q.; Keto, E. R.; Ho, P. T. P.; Rodríguez, L. F.; Zapata, L.; Peters, T.; De Pree, C. G.

    2013-12-01

    The Multi-scale Continuum and Line Exploration of W49 is a comprehensive gas and dust survey of the giant molecular cloud (GMC) of W49A, the most luminous star-formation region in the Milky Way. The project covers, for the first time, the entire GMC at different scales and angular resolutions. In this paper, we present (1) an all-configuration Submillimeter Array mosaic in the 230 GHz (1.3 mm) band covering the central ~3' × 3' (~10 pc, known as W49N), where most of the embedded massive stars reside and (2) Purple Mountain Observatory 14 m telescope observations in the 90 GHz band, covering the entire GMC with maps of up to ~35' × 35' in size, or ~113 pc. We also make use of archival data from the Very Large Array, JCMT-SCUBA, the IRAM 30 m telescope, and the Caltech Submillimeter Observatory BOLOCAM Galactic Plane Survey. We derive the basic physical parameters of the GMC at all scales. Our main findings are as follows. (1) The W49 GMC is one of the most massive in the Galaxy, with a total mass M gas ~ 1.1 × 106 M ⊙ within a radius of 60 pc. Within a radius of 6 pc, the total gas mass is M gas ~ 2 × 105 M ⊙. At these scales, only ~1% of the material is photoionized. The mass reservoir is sufficient to form several young massive clusters (YMCs) as massive as a globular cluster. (2) The mass of the GMC is distributed in a hierarchical network of filaments. At scales <10 pc, a triple, centrally condensed structure peaks toward the ring of HC H II regions in W49N. This structure extends to scales from ~10 to 100 pc through filaments that radially converge toward W49N and its less-prominent neighbor W49S. The W49A starburst most likely formed from global gravitational contraction with localized collapse in a "hub-filament" geometry. (3) Currently, feedback from the central YMCs (with a present mass M cl >~ 5 × 104 M ⊙) is still not enough to entirely disrupt the GMC, but further stellar mass growth could be enough to allow radiation pressure to clear the

  11. Microlensing of the broad line region in 17 lensed quasars

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

    When an image of a strongly lensed quasar is microlensed, the different components of its spectrum are expected to be differentially magnified owing to the different sizes of the corresponding emitting region. Chromatic changes are expected to be observed in the continuum while the emission lines should be deformed as a function of the size, geometry and kinematics of the regions from which they originate. Microlensing of the emission lines has been reported only in a handful of systems so far. In this paper we search for microlensing deformations of the optical spectra of pairs of images in 17 lensed quasars with bolometric luminosities between 1044.7 - 47.4 erg/s and black hole masses 107.6 - 9.8 M⊙. This sample is composed of 13 pairs of previously unpublished spectra and four pairs of spectra from literature. Our analysis is based on a simple spectral decomposition technique which allows us to isolate the microlensed fraction of the flux independently of a detailed modeling of the quasar emission lines. Using this technique, we detect microlensing of the continuum in 85% of the systems. Among them, 80% show microlensing of the broad emission lines. Focusing on the most common emission lines in our spectra (C III] and Mg II) we detect microlensing of either the blue or the red wing, or of both wings with the same amplitude. This observation implies that the broad line region is not in general spherically symmetric. In addition, the frequent detection of microlensing of the blue and red wings independently but not simultaneously with a different amplitude, does not support existing microlensing simulations of a biconical outflow. Our analysis also provides the intrinsic flux ratio between the lensed images and the magnitude of the microlensing affecting the continuum. These two quantities are particularly relevant for the determination of the fraction of matter in clumpy form in galaxies and for the detection of dark matter substructures via the identification

  12. Reverberation Mapping of the Broad Line Region: Application to a Hydrodynamical Line-driven Disk Wind Solution

    NASA Astrophysics Data System (ADS)

    Waters, Tim; Kashi, Amit; Proga, Daniel; Eracleous, Michael; Barth, Aaron J.; Greene, Jenny

    2016-08-01

    The latest analysis efforts in reverberation mapping are beginning to allow reconstruction of echo images (or velocity-delay maps) that encode information about the structure and kinematics of the broad line region (BLR) in active galactic nuclei (AGNs). Such maps can constrain sophisticated physical models for the BLR. The physical picture of the BLR is often theorized to be a photoionized wind launched from the AGN accretion disk. Previously we showed that the line-driven disk wind solution found in an earlier simulation by Proga and Kallman is virialized over a large distance from the disk. This finding implies that, according to this model, black hole masses can be reliably estimated through reverberation mapping techniques. However, predictions of echo images expected from line-driven disk winds are not available. Here, after presenting the necessary radiative transfer methodology, we carry out the first calculations of such predictions. We find that the echo images are quite similar to other virialized BLR models such as randomly orbiting clouds and thin Keplerian disks. We conduct a parameter survey exploring how echo images, line profiles, and transfer functions depend on both the inclination angle and the line opacity. We find that the line profiles are almost always single peaked, while transfer functions tend to have tails extending to large time delays. The outflow, despite being primarily equatorially directed, causes an appreciable blueshifted excess on both the echo image and line profile when seen from lower inclinations (i≲ 45^\\circ ). This effect may be observable in low ionization lines such as {{H}}β .

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

    NASA Astrophysics Data System (ADS)

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

    2010-10-01

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

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

    SciTech Connect

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

    2010-10-20

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

  15. Seafloor geology of the U.S. Line Islands region

    NASA Astrophysics Data System (ADS)

    Jones, M.; Eakins, B.; Barth, G. A.

    2013-12-01

    Marine geophysical surveys of the U.S. Extended Continental Shelf and Exclusive Economic Zone in the U.S. portion of the Line Islands (Kingman Reef and Palmyra Atoll) have permitted the creation of a geologic map of the seafloor surrounding the islands. Source data include modern multibeam swath sonar surveys, GLORIA sidescan sonar imagery, and seismic reflection profiles. The region is principally comprised of a high bathymetric ridge that the islands sit atop, which is the source of significant sediment found in the region, and a seamount province to the northwest; the entire area is elevated above nearby abyssal plains. Analysis of seamount summit depths in the area show that flat-topped seamounts ('guyots') are found down to 1650 meters below sea level, while the summits of peaked seamounts are principally, though not exclusively, found at deeper depths. Landslide deposits, sediment channels and other bedforms are also identified.

  16. View facing north, Structure 162 in foreground, as Transmission Line ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View facing north, Structure 16-2 in foreground, as Transmission Line turns at intersection of Powerline Road and US 87 - Havre Rainbow Transmission Line, Havre City to Great Falls vicinity, Montana, Great Falls, Cascade County, MT

  17. View facing south, near Structure 515, of Transmission Line rising ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View facing south, near Structure 51-5, of Transmission Line rising out of Marias River Valley - Havre Rainbow Transmission Line, Havre City to Great Falls vicinity, Montana, Great Falls, Cascade County, MT

  18. LINE-OF-SIGHT SHELL STRUCTURE OF THE CYGNUS LOOP

    SciTech Connect

    Uchida, Hiroyuki; Tsunemi, Hiroshi; Katsuda, Satoru; Kimura, Masashi; Kosugi, Hiroko; Takahashi, Hiroaki

    2009-11-10

    We conducted a comprehensive study on the shell structure of the Cygnus Loop using 41 observation data obtained by the Suzaku and the XMM-Newton satellites. To investigate the detailed plasma structure of the Cygnus Loop, we divided our fields of view into 1042 box regions. From the spectral analysis, the spectra obtained from the limb of the Loop are well fitted by the single-component non-equilibrium ionization plasma model. On the other hand, the spectra obtained from the inner regions are well fitted by the two-component model. As a result, we confirmed that the low-temperature and high-temperature components originated from the surrounding interstellar matter (ISM) and the ejecta of the Loop, respectively. From the best-fit results, we showed a flux distribution of the ISM component. The distribution clearly shows the limb-brightening structure, and we found out some low-flux regions. Among them, the south blowout region has the lowest flux. We also found other large low-flux regions at slightly west and northeast from the center. We estimated the former thin shell region to be approx1.{sup 0}3 in diameter and concluded that there exists a blowout along the line of sight in addition to the south blowout. We also calculated the emission measure distribution of the ISM component and showed that the Cygnus Loop is far from the result obtained by a simple Sedov evolution model. From the results, we support that the Cygnus Loop originated from a cavity explosion. The emission measure distribution also suggests that the cavity-wall density is higher in the northeast than that in the southwest. These results suggest that the thickness of the cavity wall surrounding the Cygnus Loop is not uniform.

  19. Line profiles and the kinematics of the narrow-line region in Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    De Robertis, M. M.; Shaw, Richard A.

    1990-01-01

    High signal-to-noise ratio and long-slit CCD spectra at about 100 km/sec resolution have been obtained for six high-ionization Seyfert galaxies. By subtracting the stellar absorption features with the aid of continuum templates, and using deblending techniques, the asymmetry indices of a number of optical emission-line profiles were measured, spanning a wide range in both ionization potential and critical density in each galaxy. The fundamental problem of the cloud-motion direction in the narrow-line region (NLR) has been studied, using these measurements and on the assumption that the preponderance of blueward profile asymmetries requires radial motion as well as a source of extinction. Simple and spherically symmetric NLR simulations are performed to demonstrate that infall and outflow models can be distinguished by comparing asymmetry indices as a function of ionization potential and critical density.

  20. 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)

    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

    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).

  1. Line profile studies of hydrodynamical models of cometary compact H II regions

    NASA Astrophysics Data System (ADS)

    Zhu, Feng-Yao; Zhu, Qing-Feng

    2015-06-01

    We simulate the evolution of cometary H II regions based on several champagne flow models and bow shock models, and calculate the profiles of the [Ne II] fine-structure line at 12.81 μm, the H30α recombination line and the [Ne III] fine-structure line at 15.55 μm for these models at different inclinations of 0°, 30° and 60°. We find that the profiles in the bow shock models are generally different from those in the champagne flow models, but the profiles in the bow shock models with lower stellar velocity (≤ 5 km s-1) are similar to those in the champagne flow models. In champagne flow models, both the velocity of peak flux and the flux weighted central velocities of all three lines point outward from molecular clouds. In bow shock models, the directions of these velocities depend on the speed of stars. The central velocities of these lines are consistent with the stellar motion in the high stellar speed cases, but they are opposite directions from the stellar motion in the low speed cases. We notice that the line profiles from the slit along the symmetrical axis of the projected 2D image of these models are useful for distinguishing bow shock models from champagne flow models. It is also confirmed by the calculation that the flux weighted central velocity and the line luminosity of the [Ne III] line can be estimated from the [Ne II] line and the H30α line.

  2. Physical Conditions in the Source Region of a Zebra Structure

    NASA Astrophysics Data System (ADS)

    Yasnov, L. V.; Karlický, M.; Stupishin, A. G.

    2016-07-01

    We analyze the physical conditions in the source region of a zebra structure, observed with the Ondřejov radiospectrograph during the 1 August 2010 solar flare. To determine the gyro-frequency harmonic numbers of the observed zebra lines, we compute the magnetic field strength, the electron density, and their spatial scales in the source region of the zebra structure. The region where the flare occurred is analyzed using EUV (171 Å and 335 Å) observations. To determine the conditions in the zebra source region, the magnetic field structure is reconstructed using observed photospheric magnetic field data. By computing the dependence of the magnetic field vs. height in this reconstruction and by comparing the magnetic field strength derived from the zebra structure, we determine the dependence of the electron density vs. height in the zebra source-region. We identify the loops where the zebra structure was generated at heights of about 2.5 - 3.3 Mm. Assuming the barometric law for the electron density, we determine the temperature in the zebra source-region to be T ≈ 2.0 × 104 K. Comparing the obtained values of the temperature and electron density in the zebra source-region with a model of the solar atmosphere, we find that the zebra structure was generated in the transition region, in agreement with our previous results.

  3. Physical Conditions in the Source Region of a Zebra Structure

    NASA Astrophysics Data System (ADS)

    Yasnov, L. V.; Karlický, M.; Stupishin, A. G.

    2016-08-01

    We analyze the physical conditions in the source region of a zebra structure, observed with the Ondřejov radiospectrograph during the 1 August 2010 solar flare. To determine the gyro-frequency harmonic numbers of the observed zebra lines, we compute the magnetic field strength, the electron density, and their spatial scales in the source region of the zebra structure. The region where the flare occurred is analyzed using EUV (171 Å and 335 Å) observations. To determine the conditions in the zebra source region, the magnetic field structure is reconstructed using observed photospheric magnetic field data. By computing the dependence of the magnetic field vs. height in this reconstruction and by comparing the magnetic field strength derived from the zebra structure, we determine the dependence of the electron density vs. height in the zebra source-region. We identify the loops where the zebra structure was generated at heights of about 2.5 - 3.3 Mm. Assuming the barometric law for the electron density, we determine the temperature in the zebra source-region to be T ≈ 2.0 × 104~K. Comparing the obtained values of the temperature and electron density in the zebra source-region with a model of the solar atmosphere, we find that the zebra structure was generated in the transition region, in agreement with our previous results.

  4. Neutral-Line Magnetic Shear and Enhanced Coronal Heating in Solar Active Regions

    NASA Technical Reports Server (NTRS)

    Falconer, D. A.; Moore, R. L.; Porter, J. G.; Gary, G. A.; Shimizu, T.

    1997-01-01

    By examining the magnetic structure at sites in the bright coronal interiors of active regions that are not flaring but exhibit persistent strong coronal heating, we establish some new characteristics of the magnetic origins of this heating. We have examined the magnetic structure of these sites in five active regions, each of which was well observed by both the Yohkoh SXT and the Marshall Space Flight Center Vector Magnetograph and showed strong shear in its magnetic field along part of at least one neutral line (polarity inversion). Thus, we can assess whether this form of nonpotential field structure in active regions is a characteristic of the enhanced coronal heating and vice versa. From 27 orbits' worth of Yohkoh SXT images of the five active regions, we have obtained a sample of 94 persistently bright coronal features (bright in all images from a given orbit), 40 long (greater than or approximately equals 20,000 km) neutral-line segments having strong magnetic shear throughout (shear angle greater than 45 deg), and 39 long neutral-line segments having weak magnetic shear throughout (shear angle less than 45 deg). From this sample, we find that: (1) all of our persistently bright coronal features are rooted in magnetic fields that are stronger than 150 G; (2) nearly all (95%) of these enhanced coronal features are rooted near neutral lines (closer than 10,000 km); (3) a great majority (80%) of the bright features are rooted near strong-shear portions of neutral lines; (4) a great majority (85%) of long strong-shear segments of neutral lines have persistently bright coronal features rooted near them; (5) a large minority (40%) of long weak-shear segments of neutral lines have persistently bright coronal features rooted near them; and (6) the brightness of a persistently bright Coronal feature often changes greatly over a few hours. From these results, we conclude that most persistent enhanced heating of coronal loops in active regions: (1) requires the

  5. HST/FOC imaging of the narrow-line region of NGC 1068

    NASA Technical Reports Server (NTRS)

    Macchetto, F.; Capetti, A.; Sparks, W. B.; Axon, D. J.; Boksenberg, A.

    1994-01-01

    We present imaging observations of NGC 1068 taken with the COSTAR-corrected (Corrective-Optics Space Telescope Axial Replacement) Faint Object Camera (FOC) on board the Hubble Space Telescope (HST) in the UV and optical continuum and (O III) emission lines. From these observations the structure of the nuclear region of NGC 1068 is shown to be very complex. Bright filamentary and patchy structures are intermingled with dark lanes. Other interesting features are identified, including the location of the UV peak with respect to the peak of line emission, the existence of an unusual 'twin-crescent' object near the nucleus, and point sources in the field. In the UV to optical flux ratio image, an extended conical region stands out for its blue color which may be tracing reflected nuclear light.

  6. 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)

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

    1994-01-01

    , 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.

  7. Fe K LINE COMPLEX IN THE NUCLEAR REGION OF NGC 253

    SciTech Connect

    Mitsuishi, Ikuyuki; Yamasaki, Noriko Y.; Takei, Yoh

    2011-12-15

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

  8. Harnessing natural product assembly lines: structure, promiscuity, and engineering.

    PubMed

    Ladner, Christopher C; Williams, Gavin J

    2016-03-01

    Many therapeutically relevant natural products are biosynthesized by the action of giant mega-enzyme assembly lines. By leveraging the specificity, promiscuity, and modularity of assembly lines, a variety of strategies has been developed that enables the biosynthesis of modified natural products. This review briefly summarizes recent structural advances related to natural product assembly lines, discusses chemical approaches to probing assembly line structures in the absence of traditional biophysical data, and surveys efforts that harness the inherent or engineered promiscuity of assembly lines for the synthesis of non-natural polyketides and non-ribosomal peptide analogues. PMID:26527577

  9. Inspection of composite structures using line scanning thermography

    NASA Astrophysics Data System (ADS)

    Ley, Obdulia; Butera, Manny; Godinez, Valery

    2012-06-01

    This work deals with the non destructive analysis of different composite parts and structures using Line Scanning Thermography (LST), a non-contact inspection method based in dynamic thermography. The LST technique provides a quick and efficient methodology to scan wide areas rapidly; the technique has been used on the inspection of composite propellers, sandwich panels, motor case tubes and wind turbine blades, among others. In LST a line heat source is used to thermally excite the surface under study while an infrared detector records the transient surface temperature variation of the heated region. Line Scanning Thermography (LST), has successfully been applied to determine the thickness of metallic plates and to assess boiler tube thinning. In this paper the LST protocols developed for the detection of sub-surface defects in different composite materials commonly used in aerospace applications, plates will be presented. In most cases the thermal images acquired using LST will be compared with ultrasonic c-scans. The fundamentals of LST will be discussed, as well as the limitations of this technique for NDT inspection.

  10. Exotic structures near the drip lines

    SciTech Connect

    Sharma, M. M.; Saldanha, A. A.; Sharma, J. K.

    2011-10-28

    In our recent study of the isotope shifts of Kr isotopes near rp-process path in the framework of the RMF theory, we have found that due to large shell gaps in the deformed space, several N = Z nuclei exhibit the double magicity of protons and neutrons. These nuclei are known to contribute to large abundances in the rp-process nucleosynthesis and have been shown to be the waiting-point nuclei. In another study of the shell effects at N = 126 near the neutron drip line, we have found that nuclei exhibit additional stability beyond the neutron drip line.

  11. Untangling the Recombination Line Emission from H II Regions with Multiple Velocity Components

    NASA Astrophysics Data System (ADS)

    Anderson, L. D.; Hough, L. A.; Wenger, Trey V.; Bania, T. M.; Balser, Dana S.

    2015-09-01

    H ii regions are the ionized spheres surrounding high-mass stars. They are ideal targets for tracing Galactic structure because they are predominantly found in spiral arms and have high luminosities at infrared and radio wavelengths. In the Green Bank Telescope H ii Region Discovery Survey (GBT HRDS), we found that \\gt 30% of first Galactic quadrant H ii regions have multiple hydrogen radio recombination line (RRL) velocities, which makes determining their Galactic locations and physical properties impossible. Here we make additional GBT RRL observations to determine the discrete H ii region velocity for all 117 multiple-velocity sources within 18^\\circ \\lt {\\ell }\\lt 65^\\circ . The multiple-velocity sources are concentrated in the zone 22^\\circ \\lt {\\ell }\\lt 32^\\circ , coinciding with the largest regions of massive star formation, which implies that the diffuse emission is caused by leaked ionizing photons. We combine our observations with analyses of the electron temperature, molecular gas, and carbon recombination lines to determine the source velocities for 103 discrete H ii regions (88% of the sample). With the source velocities known, we resolve the kinematic distance ambiguity for 47 regions, and thus determine their heliocentric distances.

  12. The line-emitting regions of the exceptional Seyfert galaxy Markarian 359

    SciTech Connect

    Veilleux, S. )

    1991-02-01

    The results of a kinematic study of the narrow- and broad-line regions in Mrk 359 are presented. The emission-line profiles between 4600 and 7500 A are used to derive the physical characteristics of the line-emitting gas. Many aspects of the emission-line profiles of Mrk 359 make this object an exceptional Seyfert galaxy: extremely small widths of both the forbidden lines and the broad component of the permitted lines, absence of profile substructure, large blueward asymmetry of the high-ionization forbidden lines despite the apparent absence of reddening in the narrow-line region. Various scenarios are proposed to explain these results. 65 refs.

  13. SMILES (SIMPLIFIED MOLECULAR IDENTIFICATION AND LINE ENTRY SYSTEM): A LINE NOTATION AND COMPUTERIZED INTERPRETER FOR CHEMICAL STRUCTURES

    EPA Science Inventory

    A line notation syntax and software interpreter for specifying chemical structures on small and large computers is presented. The Simplified Molecular Identification and Line Entry System, SMILES, contains the advantages of line notations for specifying structures but avoids the ...

  14. Emission line spectropolarimetry and circumstellar structures

    NASA Astrophysics Data System (ADS)

    Vink, Jorick S.

    2015-10-01

    We discuss the role of linear emission-line polarimetry in a wide set of stellar environments, involving the accretion disks around young pre-main sequence stars, to the aspherical outflows from O stars, luminous blue variables and Wolf-Rayet stars, just prior to explosion as a supernova or a gamma-ray burst. We predict subtle QU line signatures, such as single/double QU loops for un/disrupted disks. Whilst there is plenty of evidence for single QU loops, suggesting the presence of disrupted disks around young stars, current sensitivity (with S/N of order 1000) is typically not sufficient to allow for quantitative 3D Monte Carlo modeling. However, the detection of our predicted signatures is expected to become feasible with the massive improvement in sensitivity of extremely large mirrors.

  15. The Diagnostic Potential of Transition Region Lines Undergoing Transient Ionization in Dynamic Events

    NASA Astrophysics Data System (ADS)

    Doyle, J. G.; Giunta, A.; Singh, A.; Madjarska, M. S.; Summers, H.; Kellett, B. J.; O'Mullane, M.

    2012-09-01

    We discuss the diagnostic potential of high cadence UV spectral data when transient ionization is considered. For this we use high cadence UV spectra taken during the impulsive phase of a solar flare (observed with instruments on-board the Solar Maximum Mission) which showed excellent correspondence with hard X-ray pulses. The ionization fraction of the transition region ion O v and, in particular, the contribution function for the O v 1371 Å line are computed within the Atomic Data and Analysis Structure, which is a collection of fundamental and derived atomic data and codes to manipulate them. Due to transient ionization, the O v 1371 Å line is enhanced in the first fraction of a second with the peak in the line contribution function occurring initially at a higher electron temperature than in ionization equilibrium. The rise time and enhancement factor depend mostly on the electron density. The fractional increase in the O v 1371 Å emissivity due to transient ionization can reach a factor of two-four and can explain the fast response in the line flux of transition regions ions during the impulsive phase of flares solely as a result of transient ionization. This technique can be used to diagnose the electron temperature and density of solar flares observed with the forthcoming Interface Region Imaging Spectrograph.

  16. Ig Constant Region Effects on Variable Region Structure and Function.

    PubMed

    Janda, Alena; Bowen, Anthony; Greenspan, Neil S; Casadevall, Arturo

    2016-01-01

    The adaptive humoral immune response is responsible for the generation of antimicrobial proteins known as immunoglobulin molecules or antibodies. Immunoglobulins provide a defense system against pathogenic microbes and toxins by targeting them for removal and/or destruction. Historically, antibodies have been thought to be composed of distinct structural domains known as the variable and constant regions that are responsible for antigen binding and mediating effector functions such as opsonization and complement activation, respectively. These domains were thought to be structurally and functionally independent. Recent work has revealed however, that in some families of antibodies, the two regions can influence each other. We will discuss the body of work that led to these observations, as well as the mechanisms that have been proposed to explain how these two different antibody regions may interact in the function of antigen binding. PMID:26870003

  17. Ig Constant Region Effects on Variable Region Structure and Function

    PubMed Central

    Janda, Alena; Bowen, Anthony; Greenspan, Neil S.; Casadevall, Arturo

    2016-01-01

    The adaptive humoral immune response is responsible for the generation of antimicrobial proteins known as immunoglobulin molecules or antibodies. Immunoglobulins provide a defense system against pathogenic microbes and toxins by targeting them for removal and/or destruction. Historically, antibodies have been thought to be composed of distinct structural domains known as the variable and constant regions that are responsible for antigen binding and mediating effector functions such as opsonization and complement activation, respectively. These domains were thought to be structurally and functionally independent. Recent work has revealed however, that in some families of antibodies, the two regions can influence each other. We will discuss the body of work that led to these observations, as well as the mechanisms that have been proposed to explain how these two different antibody regions may interact in the function of antigen binding. PMID:26870003

  18. A far-infrared molecular and atomic line survey of the Orion KL region

    NASA Astrophysics Data System (ADS)

    Lerate, M. R.; Barlow, M. J.; Swinyard, B. M.; Goicoechea, J. R.; Cernicharo, J.; Grundy, T. W.; Lim, T. L.; Polehampton, E. T.; Baluteau, J.-P.; Viti, S.; Yates, J.

    2006-08-01

    We have carried out a high spectral resolution (λ/Δλ ~ 6800-9700) line survey towards the Orion Kleinmann-Low (KL) cluster from 44 to 188 μm. The observations were taken with the Long Wavelength Spectrometer (LWS) in Fabry-Pérot mode, on board the Infrared Space Observatory (ISO). A total of 152 lines are clearly detected and a further 34 features are present as possible detections. The spectrum is dominated by the molecular species H2O, OH and CO, along with [OI] and [CII] lines from photodissociation region (PDR) or shocked gas and [O III] and [NIII] lines from the foreground M42 HII region. Several isotopic species, as well as NH3, are also detected. HDO and H3O+ are tentatively detected for the first time in the far-infrared (FIR) range towards Orion KL. A basic analysis of the line observations is carried out, by comparing with previous measurements and published models and deriving rotational temperatures and column densities in the case of the molecular species. Analysis of the [OI] and [CII] fine structure lines indicates that although a shock model can reproduce the observed [OI] surface brightness levels, it falls short of the observed [CII] level by more than a factor of 30. A PDR model can reproduce the [OI] 63.2 μm and [CII] surface brightness levels within 35 per cent, although overpredicting the LWS [OI] 145.5 μm-emission by a factor of 2.7. The 70 water lines and 22 OH lines detected by the survey appear with mainly P Cygni profiles at the shortest survey wavelengths and with mainly pure emission profiles at the longest survey wavelengths. The emission and absorption velocity peaks of the water and OH lines indicate that they are associated with gas expanding in the outflow from the KL cluster. The estimated column densities are (2-5) × 1014 cm-2 for H2O and (2.5-5.1) × 1016 cm-2 for OH. The 26 detected CO lines confirm the presence of three distinct components, with temperature and column density combinations ranging from 660 K, 6 × 1017

  19. Properties of solar coronal active regions deduced from X-ray line spectra

    NASA Astrophysics Data System (ADS)

    McKenzie, D. L.

    1987-11-01

    Spectra from the SOLEX B RAP spectrometer have been used to analyze the temperature and density structure of over 100 nonflaring solar active regions. Density measurements that used the R ratio of O VII indicated that few regions have electron densities higher than ≡3×109cm-3. In a few cases, flare-productive regions had measured densities approximately twice this high. Temperature-sensitive line ratios in the helium-like ions O VII, Ne IX, and Mg XI were used to decude the general properties of the differential emission-measure function B(T) for nonflaring regions. B(T) falls off with increasing temperature above a peak temperature that is almost always lower than Tm(O VII) = 1.8×106K.

  20. Regions of Generation and Optical Thicknesses of dm-Zebra Lines

    NASA Astrophysics Data System (ADS)

    Yasnov, L. V.; Karlický, M.

    2015-07-01

    Using a new model based on the double plasma resonance (DPR), we show that the zebra structure seen in solar radio bursts is generated in the transition region and at the tops of the magnetic arcade. The magnetic field in zebra sources is probably weaker than 150 gauss. According to this model, a generation of zebras in stronger magnetic fields is improbable. The high-frequency boundary of decimetric zebras depends on the background electron plasma density, but not on the magnetic field strength in the generation regions. The bremsstrahlung absorption in atmospheric layers above the DPR zebra generation region and the cyclotron absorption in the DPR region and in the gyroresonance layers at higher altitudes limit the spectrum of zebras from both high-frequency and low-frequency sides. While the bremsstrahlung reduces the emission from the high-frequency side, the cyclotron absorption limits the low-frequency side. The observed frequency range and the number of observed zebra lines are determined not only by these absorptions, but also by appropriate distribution functions of superthermal electrons and plasma conditions in this region. Low-frequency (metric) zebra emissions can be generated at high altitudes. Computations show that such emissions can escape from the DPR generation region only at high gyro-harmonics () and with many zebra lines.

  1. Flux Line Lattice Structure in YNi2B2C

    NASA Astrophysics Data System (ADS)

    Kawano-Furukawa, Hazuki; Ohira-Kawamura, Seiko; Tsukagoshi, Hitomi; Kobayashi, Chiyako; Nagata, Takashi; Sakiyama, Naoki; Yoshizawa, Hideki; Yethiraj, Mohana; Suzuki, Jun-ichi; Takeya, Hiroyuki

    2008-10-01

    Recently Nakai et al. reported a theoretical H-T phase diagram of flux line lattice (FLL) structure in which successive transitions from a triangular, a square (\\squarev), a triangular and another square (\\squareg) occur with increasing a magnetic field. Here \\squarev and \\squareg indicate the FLL structures reflecting anisotropies in the Fermi velocity and the superconducting gap, respectively. In the case of YNi2B2C, \\squarev and \\squareg should rotate by 45°. The low field transition from triangular to \\squarev is observed in RENi2B2C (\\textit{RE}=Er, Tm, Lu, and Y). However, there is no experimental evidence for the appearance of \\squareg phase so far. We studied the FLL structure of YNi2B2C in the higher field region by small-angle neutron scattering. Our results show that a large area of the H-T phase diagram is occupied by \\squarev phase and there is no evidence for the appearance of \\squareg lattice.

  2. Resolving the coronal line region of NGC 1068 with near-infrared integral field spectroscopy

    NASA Astrophysics Data System (ADS)

    Mazzalay, X.; Rodríguez-Ardila, A.; Komossa, S.; McGregor, Peter J.

    2013-04-01

    We present adaptive optics-assisted J- and K-band integral field spectroscopy of the inner 300 × 300 pc of the Seyfert 2 galaxy NGC 1068. The data were obtained with the Gemini Near-infrared Integral-Field Spectrograph integral field unit spectrometer, which provided us with high-spatial and high-spectral resolution sampling. The wavelength range covered by the observations allowed us to study the [Ca VIII], [Si VI], [Si VII], [Al IX] and [S IX] coronal line (CL) emission, covering ionization potentials up to 328 eV. The observations reveal very rich and complex structures, both in terms of velocity fields and emission-line ratios. The CL emission is elongated along the NE-SW direction, with the stronger emission preferentially localized to the NE of the nucleus. CLs are emitted by gas covering a wide range of velocities, with maximum blueshifts/redshifts of ˜ -1600/1000 km s-1. There is a trend for the gas located on the NE side of the nucleus to be blueshifted while the gas located towards the SW is redshifted. The morphology and the kinematics of the near-infrared CLs are in very good agreement with the ones displayed by low-ionization lines and optical CLs, suggesting a common origin. The line flux distributions, velocity maps, ionization structure (traced by the [Si VII]/[Si VI] emission-line ratio) and low-ionization emission-line ratios (i.e. [Fe II]/Paβ and [Fe II]/[P II]) suggest that the radio jet plays an important role in the structure of the CL region of this object, and possibly in its kinematics.

  3. Analysis of magnesium XI line profiles from solar active regions

    NASA Technical Reports Server (NTRS)

    Blake, R. L.; Cowan, R. D.; Felthauser, H.; Fenimore, E. E.; Hockaday, M. P.; Bely-Dubau, F.; Faucher, P.; Steenman-Clark, L.

    1984-01-01

    High-resolution solar spectra of the Mg XI 1s2 1S0-1s2p 1P1 resonance line at 9.169 A and the associated nearby satellite lines obtained from two rocket-borne crystal spectrometer measurements are presented. Comparisons with two independent sets of theoretical calculations for the 1s2nl-1s2pnl dielectronic satellite lines with n = 3-7 indicate electron temperatures of 4-4.5 million K. Measured line widths indicate either that the ion temperature exceeds the electron temperature by about a million K or that about 28 km/s of turbulence is present.

  4. Potential structures and particle acceleration on auroral field lines

    NASA Astrophysics Data System (ADS)

    Gorney, D. J.

    Observations of plasmas and electric field activity within regions of auroral particle acceleration have verified the existence of electric fields with components parallel to the magnetic field over large altitude regions. Evidence is presented which indicates that small-ampliatude double layers along the auroral magnetic field lines may provide a mechanism for the maintenance of auroral ion potential. Evidence is also presented of downward-directed parallel electric fields along the magnetic field lines in the return current region. It is suggested that the downward electric fields may have significant effects on ion trajectories, and further theoretical investigation of the effects of downward parallel electric fields on ion conic formation is recommended.

  5. Detail of insulator array at first line structure showing historic ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of insulator array at first line structure showing historic porcelain suspension insulators in strings of eight, porcelain jumper support insulators in strings of six, arch rings and ball weights - Morony Hydroelectric Facility, Morony-to-Rainbow 100 kV Transmission Line, West bank of the Missouri River, Great Falls, Cascade County, MT

  6. Fine structure line emission from supergiants

    NASA Technical Reports Server (NTRS)

    Haas, Michael R.; Glassgold, Alfred E.; Tielens, Alexander G. G. M.

    1995-01-01

    We have detected (O I) 63 micron and (Si II) 35 micron emission from the oxygen-rich, M supergiants alpha Orionis (Betelgeuse), alpha Scorpii (Antares), and alpha Herculis (Rasalgethi). The measured fluxes indicate that the emission originates in dense, warm gas in the inner envelope or transition region where molecules and dust are expected to form and the acceleration of the wind occurs. Mass-loss rates are derived, evidence for time variability is presented, and results for other evolved stars are included.

  7. Fine structure line emission from supergiants

    NASA Astrophysics Data System (ADS)

    Haas, Michael R.; Glassgold, Alfred E.; Tielens, Alexander G. G. M.

    We have detected (O I) 63 micron and (Si II) 35 micron emission from the oxygen-rich, M supergiants alpha Orionis (Betelgeuse), alpha Scorpii (Antares), and alpha Herculis (Rasalgethi). The measured fluxes indicate that the emission originates in dense, warm gas in the inner envelope or transition region where molecules and dust are expected to form and the acceleration of the wind occurs. Mass-loss rates are derived, evidence for time variability is presented, and results for other evolved stars are included.

  8. 53. LAYOUT OF POWER CANAL LINE, LIST OF STRUCTURES Courtesy ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    53. LAYOUT OF POWER CANAL LINE, LIST OF STRUCTURES Courtesy of Reclamation Service, Salt River Project, Arizona - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

  9. Broad-line region at the center of the Galaxy

    SciTech Connect

    Geballe, T.R.; Wade, R.; Krisciunas, K.; Gatley, I.; Bird, M.C.

    1987-09-01

    The high-velocity wings of the Br-alpha (405 micron) line at the Galactic center have been mapped with a 2.5 arcsec beam and at a velocity resolution of 400 km/s. The peak intensity of the high-velocity line emission is coincident with the position of the source IRS 16 Center. It is suggested that the broad-line emission either is from more than one compact wind source or is the result of an interaction between an ultrahigh velocity wind and slower moving ionized gas in the bar whose trajectory brings it close to the wind source. 31 references.

  10. Line-of-sight structure toward strong lensing galaxy clusters

    SciTech Connect

    Bayliss, Matthew B.; Johnson, Traci; Sharon, Keren; Gladders, Michael D.; Oguri, Masamune

    2014-03-01

    We present an analysis of the line-of-sight structure toward a sample of 10 strong lensing cluster cores. Structure is traced by groups that are identified spectroscopically in the redshift range, 0.1 ≤ z ≤ 0.9, and we measure the projected angular and comoving separations between each group and the primary strong lensing clusters in each corresponding line of sight. From these data we measure the distribution of projected angular separations between the primary strong lensing clusters and uncorrelated large-scale structure as traced by groups. We then compare the observed distribution of angular separations for our strong lensing selected lines of sight against the distribution of groups that is predicted for clusters lying along random lines of sight. There is clear evidence for an excess of structure along the line of sight at small angular separations (θ ≤ 6') along the strong lensing selected lines of sight, indicating that uncorrelated structure is a significant systematic that contributes to producing galaxy clusters with large cross sections for strong lensing. The prevalence of line-of-sight structure is one of several biases in strong lensing clusters that can potentially be folded into cosmological measurements using galaxy cluster samples. These results also have implications for current and future studies—such as the Hubble Space Telescope Frontier Fields—that make use of massive galaxy cluster lenses as precision cosmological telescopes; it is essential that the contribution of line-of-sight structure be carefully accounted for in the strong lens modeling of the cluster lenses.

  11. A yield line evaluation methodology for reinforced concrete structures

    SciTech Connect

    Mertz, G.E.

    1997-03-01

    Yield line theory is an analytical technique that can be used to determine the ultimate bending capacity of flat reinforced concrete plates. Alternately, yield line theory, combined with rotation limits, can be used to determine the energy absorption capacity of plates subjected to impulsive and impact loadings. Typical components analyzed by yield line theory are basements, floor and roof slabs subjected to vertical loads, and walls subjected to out of plane loadings. Yield line theory equates plastic strain energy to external work for postulated collapse mechanisms. Multiple collapse mechanisms are evaluated and the mechanism with the minimum strain energy corresponds to the collapse load. Numerous investigators have verified yield line theory by experiment. Analysis by yield line theory is currently accepted by the ACI-318 Building Code Requirements for Reinforced Concrete and ACI-349 Code Requirements for Nuclear Safety Related Concrete Structures. One limitation of yield line theory is that it is computational difficult to evaluate some collapse mechanism. This problem is aggravated by the complex geometry nd reinforcing layouts commonly found in practice. The Yield Line Evaluator (YLE) is a computer program which was developed to solve computationally tedious yield line mechanisms. The program has the capability to either evaluate a single user-defined mechanism or to iterate over a range of mechanisms to determine the minimum ultimate capacity. The program is verified by comparison to a series of yield line mechanisms with known solutions.

  12. Flexible gas insulated transmission line having regions of reduced electric field

    DOEpatents

    Cookson, Alan H.; Fischer, William H.; Yoon, Kue H.; Meyer, Jeffry R.

    1983-01-01

    A gas insulated transmission line having radially flexible field control means for reducing the electric field along the periphery of the inner conductor at predetermined locations wherein the support insulators are located. The radially flexible field control means of the invention includes several structural variations of the inner conductor, wherein careful controlling of the length to depth of surface depressions produces regions of reduced electric field. Several embodiments of the invention dispose a flexible connector at the predetermined location along the inner conductor where the surface depressions that control the reduced electric field are located.

  13. TEMPERATURE STRUCTURE AND METALLICITY IN H II REGIONS

    SciTech Connect

    Rodriguez, Monica; GarcIa-Rojas, Jorge E-mail: jogarcia@iac.e

    2010-01-10

    The metallicities implied by collisionally excited lines (CELs) of heavy elements in H II regions are systematically lower than those implied by recombination lines (RLs) by factors of approx2, introducing uncertainties of the same order in the metallicities inferred for the interstellar medium of any star-forming galaxy. Most explanations of this discrepancy are based on the different sensitivities of CELs and RLs to electron temperature, and invoke either some extra heating mechanism producing temperature fluctuations in the ionized region or the addition of cold gas in metal-rich inclusions or ionized by cosmic rays or X-rays. These explanations will change the temperature structure of the ionized gas from the one predicted by simple photoionization models, and depending on which one is correct, will imply different metallicities for the emitting gas. We select nine H II regions with observed spectra of high quality and show that simple models with metallicities close to the ones implied by oxygen CELs reproduce easily their temperature structure, measured with T{sub e}([N II])/T{sub e}([O III]), and their oxygen CELs emission. We discuss the strong constraints that this agreement places on the possible explanations of the discrepancy and suggest that the simplest explanation, namely errors in the line recombination coefficients by factors approx2, might be the correct one. In such case, CELs will provide the best estimates of metallicity.

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

    NASA Technical Reports Server (NTRS)

    Clavel, J.; Wamsteker, W. A.; Reichert, G. A.; Crenshaw, D. M.; Alloin, D.

    1991-01-01

    Emission-line and UV continuum observations of the type I Seyfert galaxy NGC 5548 were carried out for a period of 8 months with the IUE satellite. It was found that both the continuum shape and the line ratios of NGC 5548, while being not unusual for type I Seyfert galaxies, are strongly variable. The UV continuum flux and broad emission line fluxed went through three large maxima and three deep minima; the ratio of miximum to minimum flux was about 4.5 for the continuum at 1350 A. The N V and the He II emission lines exhibited maximum-to-minimum flux ratios as high as those of the continuum; other ionization lines (Ly-alpha, C IV, and C III) exhibited smaller amplitude fluctuations, with the smallest being recorded for the Mg II line (about 1.3). It was found that, except for Mg II, the emission-line variations correlated extremely well with those of the 1350-A continuum.

  15. A note on chromospheric fine structure at active region polarity boundaries.

    NASA Technical Reports Server (NTRS)

    Prata, S. W.

    1971-01-01

    High resolution H-alpha filtergrams from Big Bear Solar Observatory reveal that some filamentary features in active regions have fine structure and hence magnetic field transverse to the gross structure and the zero longitudinal field line. These features are distinct from the usual active region filament, in which fine structure, magnetic field, and filament are all parallel to the zero longitudinal field line. The latter occur on boundaries between regions of weaker fields, while the former occur at boundaries between regions of stronger field.

  16. The Regional Structure of Technical Innovation

    NASA Astrophysics Data System (ADS)

    O'Neale, Dion

    2014-03-01

    There is strong evidence that the productivity per capita of cities and regions increases with population. One likely explanation for this phenomenon is that densely populated regions bring together otherwise unlikely combinations of individuals and organisations with diverse, specialised capabilities, leading to increased innovation and productivity. We have used the REGPAT patent database to construct a bipartite network of geographic regions and the patent classes for which those regions display a revealed comparative advantage. By analysing this network, we can infer relationships between different types of patent classes - and hence the structure of (patentable) technology. The network also provides a novel perspective for studying the combinations of technical capabilities in different geographic regions. We investigate measures such as the diversity and ubiquity of innovations within regions and find that diversity (resp. ubiquity) is positively (resp. negatively) correlated with population. We also find evidence of a nested structure for technical innovation. That is, specialised innovations tend to occur only when other more general innovations are already present.

  17. Fine-structure Constancy Measurements in QSO Absorption Lines

    NASA Astrophysics Data System (ADS)

    Whitmore, Jonathan B.

    2013-01-01

    The ESO Large Programme 185.A-0745 has awarded 10 nights on the VLT-UVES spectrograph for the study of the possible variation in the fine structure constant. We will present the fine-structure measurements from two lines of sight and several absorption systems. We will also present updated systematic error analyses.

  18. Physical parameters of the Orion Bar photodissociation region from radio recombination line observations at 8 mm.

    NASA Astrophysics Data System (ADS)

    Tsivilev, A. P.

    2014-10-01

    Observations of carbon (C), hydrogen and helium (H, He) radio recombination lines (RRLs) at four positions in the Orion Bar photodissociation region (PDR) and toward the center of Orion A have been performed with the RT-22 radio telescope (Pushchino) at 8 mm. The physical parameters of the PDR at these points have been estimated by comparing the carbon RRLs and infrared CII and OI lines. A hydrogen number density in the range 1.2-3.1 × 10^5 cm^-3 and a mean size of the region along the line of sight (L) in the range 0.006-0.04 pc have been derived. The PDR temperature decreases with increasing distance from the exciting star (θ 1 C Ori) from 210-230 to 140-150 K (a distance of ≃5'). The data obtained confirm the increase in the PDR size along the line of sight toward the Orion Bar, where, however, L has turned out to be less than the available values in the literature, which can be explained by the presence of clumps in the PDR. A density jump is evident in the Orion Bar region. The PDR zone encompasses the core of the HII region by a thin layer and extends farther, delineating the boundary and the ionization front of the core of the HII region in the Orion Bar and further out the boundary between the halo of the HII region and the molecular cloud. The derived emission measure (EM) toward the Orion Bar has been compared with other C RRL observations. The EM measured from carbon RRLs is EM ≃ 100(±50%) pc cm^-6, imposing constraints on the possible two-component PDR structure. Estimates show that the star θ 1 C Ori is quite sufficient as a carbon ionization source in the Orion Bar PDR. Some of the data on the ionized hot gas (HII) in this direction have been obtained from H and He RRLs. In particular, the radial velocities (V lsr) of the HII region are blueshifted with respect to V lsr of the PDR by 10-17 km s^-1, while the relative ionized helium abundance decreases with increasing distance from the star, indicating that the helium ionization zone is smaller

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

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

    Recent velocity-resolved reverberation mapping results have shown indications of possible outflowing gas from the Hβ emitting region of the broad-line region (BLR) in NGC 3227 (Denney et al. 2009, 2010). We show a preliminary velocity-delay map (VDM) from these data that suggests the 2D gas motions could not be fully and accurately interpreted from the 1D velocity-resolved reverberation signal. From the VDM, an outflow component to the emission remains possible but appears to be in addition to an underlying, disk-like BLR structure consistent in size with the measured reverberation lag. The black hole (BH) mass derived from this data is therefore secure from any uncertainties possibly derived from gravitationally unbound gas contributing to the emission. Additionally, we demonstrate that BLR emission from the C IV λ1549 broad emission line can reliably be used as a virial BH mass estimator. The presence of self-absorption, blueshifts, and asymmetries observed in C IV, and possibly connected with outflows, has raised questions in the literature regarding the reliability of using this line for mass estimates. However, our new results (Assef et al. 2011) show that C IV-based masses are in agreement with those of Hβ when (1) data quality is a priority and (2) a color-correction is applied to the luminosity used to compute the mass estimates.

  20. Radiation pressure confinement - II. Application to the broad-line region in active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Baskin, Alexei; Laor, Ari; Stern, Jonathan

    2014-02-01

    Active galactic nuclei (AGN) are characterized by similar broad emission lines properties at all luminosities (1039 - 1047 erg s-1). What produces this similarity over a vast range of 108 in luminosity? Photoionization is inevitably associated with momentum transfer to the photoionized gas. Yet, most of the photoionized gas in the broad-line region (BLR) follows Keplerian orbits, which suggests that the BLR originates from gas with a large enough column for gravity to dominate. The photoionized surface layer of the gas must develop a pressure gradient due to the incident radiation force. We present solutions for the structure of such a hydrostatic photoionized gas layer in the BLR. The gas is stratified, with a low-density highly ionized surface layer, a density rise inwards and a uniform-density cooler inner region, where the gas pressure reaches the incident radiation pressure. This radiation pressure confinement (RPC) of the photoionized layer leads to a universal ionization parameter U ˜ 0.1 in the inner photoionized layer, independent of luminosity and distance. Thus, RPC appears to explain the universality of the BLR properties in AGN. We present predictions for the BLR emission per unit covering factor, as a function of distance from the ionizing source, for a range of ionizing continuum slopes and gas metallicity. The predicted mean strength of most lines (excluding H β), and their different average-emission radii, are consistent with available observations.

  1. Capillary electrophoresis-fluorescence line-narrowing system for on-line structural characterization of molecular analytes

    SciTech Connect

    Jankowiak, R.; Zamzow, D.; Ding, W.; Small, G.J.

    1996-08-01

    We have demonstrated, for the first time, that capillary electrophoresis (CE) can be interfaced with low-temperature fluorescence line-narrowing (FLN) spectroscopy for on-line structural characterization. Detection by laser-induced fluorescence spectroscopy, under fluorescence non-line-narrowing and line-narrowing conditions, provides three-dimensional electropherograms and FLN spectra, which lead to significantly improved overall resolution and allow for structural characterization (`fingerprinting`) of molecular analytes. This novel CE-FLN system consists of a modular CE system, instrumentation for FLN spectroscopy, and a specially designed capillary cryostat (CC). An absorbance detector serves to determine the migration rates of analytes. After the 77 K fluorescence-based electropherogram is generated, the temperature of the capillary is lowered to 4.2 K for high-resolution FLN characterization. Automated translation of the CC and capillary in the direction of the capillary axis allows the separated analytes to be sequentially characterized by fluorescence spectroscopy as the capillary is translated through the laser excitation region. Detection of fluorescence from stationary CE-separated analytes significantly improves the accuracy of quantitation and structural characterization. 41 refs., 4 figs.

  2. Regional crustal structures of Pacific Northwest

    SciTech Connect

    Connard, G.; Couch, R.; Farooqui, S.; Pitts, G.S.; O'Malley, R.

    1986-04-01

    Long-wavelength gravity anomalies combined with regional seismic refraction data, obtained during the last two decades, allow a regional mapping of crustal thickness variations in the Pacific Northwest and the adjacent continental margin. When the effects of these variations in crustal thickness are removed from the gravity data, the residual gravity anomalies outline major upper crustal structures in the Pacific Northwest. Residual gravity anomalies show that the Cascade Range in Oregon fills a major north-south-trending graben. The graben is approximately 60 km wide and 160 km long, and is oriented approximately N10/sup 0/E. Its well-developed western wall exhibits a throw of 2-3 km. The Cascade Range and its associated graben overlie a prominent northeast-southwest structural trend that demarks a Mesozoic orocline. The oroclinal structure extends from the continental margin northwest of the Klamath Mountains in southwestern Oregon through the Blue Mountains in northeastern Oregon, and separates the late Mesozoic to early Tertiary basins of central Oregon and central Washington. A large regional gravity high observed over the Columbia basin in central Washington is attributed to both the thick surface layer of flood basalts and an anomalous lower crust. Gravity data integrated with seismic refraction and geologic data yield a computed model of the crustal structure of the Columbia Plateau. Removing the basalt layer of the model reveals a rift topography or complex graben structure that connects with or adjoins the Cascade graben on the southwest side of the basin and the Chiwaukun, Methow, and Republic grabens on the north side of the basin. These structures in the Pacific Northwest reflect generally east-west extension and wrench tectonics.

  3. Ultraviolet observations of the structure and dynamics of an active region at the limb

    NASA Technical Reports Server (NTRS)

    Korendyke, C. M.; Dere, K. P.; Socker, D. G.; Brueckner, G. E.; Schmieder, B.

    1995-01-01

    The structure and dynamics of active region NOAA 7260 at the limb have been studied using ultraviolet spectra and spectroheliograms obtained during the eighth rocket flight of the Naval Research Laboratory's High Resolution Telescope an Spectrograph (HRTS). The instrument configuration included a narrow-bandpass spectroheliograph to observe the Sun in the lines of C IV lambda 550 and a tandem-Wadsworth mount spectrograph to record the profiles of chromospheric transition region and coronal lines in the 1850-2670 A region. The combination of high spatial resolution and high spectral purity C IV slit jaw images with ultraviolet emission-line spectra corresponding allows examination of a variety of active region phenomena. A time series of spectroheliograms shows large-scale loop systems composed of fine-scale threads with some extending up to 100 Mm above the limb. The proper motion of several supersonic features, including a surge were measured. The accelerated plasmas appear in several different geometries and environments. Spectrograph exposures were taken with the slit positioned at a range of altitudes above the limb and provide a direct comparison between coronal, transition region and chromospheric emission line profiles. The spectral profiles of chromospheric and transition region emission lines show line-of-sight velocities up to 70 km/s. These lower temperature, emission-line spectra show small-scale spatial and velocity variations which are correlated with the threadlike structures seen in C IV. Coronal lines of Fe XII show much lower velocities and no fine structure.

  4. COEXISTENCE OF GRAVITATIONALLY-BOUND AND RADIATION-DRIVEN C IV EMISSION LINE REGIONS IN ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Wang Huiyuan; Wang Tinggui; Zhou Hongyan; Liu Bo; Dong Xiaobo; Wang Jianguo

    2011-09-01

    There are mutually contradictory views in the literature of the kinematics and structure of high-ionization line (e.g., C IV) emitting regions in active galactic nuclei (AGNs). Two kinds of broad emission line region (BELR) models have been proposed, outflow and gravitationally-bound BELR, which are supported, respectively, by blueshift of the C IV line and reverberation mapping observations. To reconcile these two apparently different models, we present a detailed comparison study between the C IV and Mg II lines using a sample of AGNs selected from the Sloan Digital Sky Survey. We find that the kinematics of the C IV region is different from that of Mg II, which is thought to be controlled by gravity. A strong correlation is found between the blueshift and asymmetry of the C IV profile and the Eddington ratio. This provides strong observational support for the postulation that the outflow is driven by radiation pressure. In particular, we find robust evidence that the C IV line region is largely dominated by outflow at high Eddington ratios, while it is primarily gravitationally-bounded at low Eddington ratios. Our results indicate that these two emitting regions coexist in most AGNs. The emission strength from these two gases varies smoothly with Eddington ratio in opposite ways. This explanation naturally reconciles the apparently contradictory views proposed in previous studies. Finally, candidate models are discussed which can account for both the enhancement of outflow emission and suppression of normal BEL in AGNs with high Eddington ratios.

  5. Prospection of genomic regions divergently selected in racing line of Quarter Horses in relation to cutting line.

    PubMed

    Meira, C T; Curi, R A; Farah, M M; de Oliveira, H N; Béltran, N A R; Silva, J A V; Mota, M D S da

    2014-11-01

    Selection of Quarter Horses for different purposes has led to the formation of lines, including racing and cutting horses. The objective of this study was to identify genomic regions divergently selected in racing line of Quarter Horses in relation to cutting line applying relative extended haplotype homozygosity (REHH) analysis, an extension of extended haplotype homozygosity (EHH) analysis, and the fixation index (F ST) statistic. A total of 188 horses of both sexes, born between 1985 and 2009 and registered at the Brazilian Association of Quarter Horse Breeders, including 120 of the racing line and 68 of the cutting line, were genotyped using single nucleotide polymorphism arrays. On the basis of 27 genomic regions identified as selection signatures by REHH and F ST statistics, functional annotations of genes were made in order to identify those that could have been important during formation of the racing line and that could be used subsequently for the development of selection tools. Genes involved in muscle growth (n=8), skeletal growth (n=10), muscle energy metabolism (n=15), cardiovascular system (n=14) and nervous system (n=23) were identified, including the FKTN, INSR, GYS1, CLCN1, MYLK, SYK, ANG, CNTFR and HTR2B. PMID:25032727

  6. Cosmic rays and the emission line regions of active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Ferland, G. J.; Mushotzky, R. F.

    1984-01-01

    The effects that the synchrotron emitting relativistic electrons could have on the emission line regions which characterize active nuclei are discussed. Detailed models of both the inner, dense, broad line region and the outer, lower density, narrow line region are presented, together with the first models of the optically emitting gas often found within extended radio lobes. If the relativistic gas which produces the synchrotron radio emission is mixed with the emission line region gas then significant changes in the emission line spectrum will result. The effects of the synchrotron emitting electrons on filaments in the Crab Nebula are discussed in an appendix, along with a comparison between the experimental calculations, which employ the mean escape probability formalism, and recent Hubbard and Puetter models.

  7. An investigation of the convective region of numerically simulated squall lines

    NASA Astrophysics Data System (ADS)

    Bryan, George Howard

    High resolution numerical simulations are utilized to investigate the thermodynamic and kinematic structure of the convective region of squall lines. A new numerical modeling system was developed for this purpose. The model incorporates several new and/or recent advances in numerical modeling, including: a mass- and energy-conserving equation set, based on the compressible system of equations; third-order Runge-Kutta time integration, with high (third to sixth) order spatial discretization; and a new method for conserved-variable mixing in saturated environments, utilizing an exact definition for ice-liquid water potential temperature. A benchmark simulation for moist environments was designed to evaluate the new model. It was found that the mass- and energy-conserving equation set was necessary to produce acceptable results, and that traditional equation sets have a cool bias that leads to systematic underprediction of vertical velocity. The model was developed to run on massively-parallel distributed memory computing systems. This allows for simulations with very high resolution. In this study, squall lines were simulated with grid spacing of 125 m over a 300 km x 60 km x 18 km domain. Results show that the 125 m simulations contain sub-cloud-scale turbulent eddies that stretch and distort plumes of high equivalent potential temperature (thetae) that rise from the pre-squall-line boundary layer. In contrast, with 1 km grid spacing the high thetae plumes rise in a laminar manner, and require parameterized subgrid terms to diffuse the high theta e air. The high resolution output is used to refine the conceptual model of the structure and lifecycle of moist absolutely unstable layers (MAULs). Moist absolute instability forms in the inflow region of the squall line and is subsequently removed by turbulent processes of varying scales. Three general MAUL regimes (MRs) are identified: a laminar MR, characterized by deep (˜2 km) MAULs that extend continuously in both

  8. Singular surfaces in the open field line region of a diverted tokamak

    SciTech Connect

    Reiman, A.

    1995-05-01

    The structure of the open field lines of a slightly nonaxisymmetric, poloidally diverted tokamak is explored by numerical integration of the field line equations for a simple model field. In practice, the nonaxisymmetry could be produced self-consistently by the nonlinear evolution of a free-boundary MHD mode, or it could be produced by field errors, or it could be imposed externally by design. In the presence of a nonaxisymmetric perturbation, the tokamak is shown to develop open field line regions of differing topology separated by singular surfaces. It is argued that the singular surfaces can be expected to play a role analogous to that of rational toroidal flux surfaces, in terms of constraining ideal MHD perturbations and thus constraining the free-energy that can be tapped by ideal MHD instabilities. The possibility of active control of free-boundary instabilities by means of currents driven on the open singular surfaces, which are directly accessible from the divertor plates, is discussed. Also discussed is the possibility of early detection of imminent disruptions through localized measurement of the singular surface currents.

  9. Line parameters for ozone hot bands in the 4.8-micron spectral region

    NASA Technical Reports Server (NTRS)

    Camy-Peyret, Claude; Flaud, Jean-Marie; Rinsland, Curtis P.; Smith, Mary Ann H.; Devi, V. Malathy

    1990-01-01

    Line positions, intensities, and lower-state energies have been calculated for nine hot bands of (O-16)3 in the 4.8-micron spectral region using improved spectroscopic parameters deduced in recent high-resolution laboratory studies. The good quality of the hot-band parameters has been verified through comparisons of line-by-line simulations with 0.005/cm-resolution laboratory spectra of ozone. The present work and the line parameters calculated for the main bands by Pickett et al. (1988) provide a complete update of ozone spectroscopic parameters in the 4.8 micron region.

  10. Doppler wavelength shifts of ultraviolet spectral lines in solar active regions

    NASA Technical Reports Server (NTRS)

    Feldman, U.; Doschek, G. A.; Cohen, L.

    1982-01-01

    Doppler shifts are measured for solar UV emission lines formed in the lower transition region of active regions. Doppler shifts in different regions at the same solar location, variations of Doppler shift with position of an active region on the disk, and variations of Doppler shift with time at the same solar location in the same active region were studied. Observations were made with the NRL slit spectrograph on Skylab. Excluding flare and flare-related phenomena, only redshifts are found whose magnitudes correspond to downflow velocities between about 4 and 17 km/s. Shifts are largest for lines formed between about 50,000 and 100,000 K, and are distinctly less for lines formed above 100,000 K. The shifts persist out to the limb, but not above it. There is no obvious change in redshift for lines measured at the same solar location over time intervals of about 20 minutes.

  11. Results and implications of new regional seismic lines in the Malay Basin

    SciTech Connect

    Leslie, W.; Ho, W.K.; Ghani, M.A. )

    1994-07-01

    Regional seismic data, which was previously acquired between 1968 and 1971 by early operators in the Malay Basin, has limitations because the sophisticated modern-day acquisition and processing techniques were not available. These old data do not permit confident mapping below 3 s (TWT), equivalent to approximately 3000 m subsea, but aeromagnetic data indicate that the total sedimentary thickness exceeds 13,000 m. Hence, existing regional seismic data with a record length of 5 s (TWT) is neither adequate to map deeper play opportunities nor able to aid in understanding the geological history of the basin. New plays at deeper levels may exist. (1) Geochemical modeling results now predict the top of the oil generation window at depths greater than previously thought. (2) Existing gas fields occur in the upper section in areas of thickest sedimentary fill but underlying targets have not been tested. (3) Past exploration has been focused on oil and not gas in deeper structures. Because of Malaysia's rapid development and its dedication to the protection of the environment, gas is becoming an increasingly important energy source. Hence, ample internal markets for additional gas discoveries are being created. A better understanding of the Malay Basin geological history will assist in locating these potential plays. To do this, Petronas acquired approximately 3000 line km of high-quality regional seismic data to further exploration efforts in this prospective region.

  12. Regional anaesthesia and analgesia on the front line.

    PubMed

    Scott, D M

    2009-11-01

    Deployment to a combat zone with the military poses many challenges to the anaesthetist. One of these challenges is the safe, rapid and comfortable initial wound management and repatriation of wounded combat soldiers to their home country or tertiary treatment facility for definitive care and rehabilitation. The current conflict in Afghanistan is associated with injury patterns that differ from wars such as Vietnam or Korea. This report describes the experience of an Australian military anaesthetist and the value of regional anaesthesia and analgesia for the care of the wounded combat soldier PMID:20014611

  13. Genomic Heterogeneity and Structural Variation in Soybean Near Isogenic Lines

    PubMed Central

    Stec, Adrian O.; Bhaskar, Pudota B.; Bolon, Yung-Tsi; Nolan, Rebecca; Shoemaker, Randy C.; Vance, Carroll P.; Stupar, Robert M.

    2013-01-01

    Near isogenic lines (NILs) are a critical genetic resource for the soybean research community. The ability to identify and characterize the genes driving the phenotypic differences between NILs is limited by the degree to which differential genetic introgressions can be resolved. Furthermore, the genetic heterogeneity extant among NIL sub-lines is an unaddressed research topic that might have implications for how genomic and phenotypic data from NILs are utilized. In this study, a recently developed high-resolution comparative genomic hybridization (CGH) platform was used to investigate the structure and diversity of genetic introgressions in two classical soybean NIL populations, respectively varying in protein content and iron deficiency chlorosis (IDC) susceptibility. There were three objectives: assess the capacity for CGH to resolve genomic introgressions, identify introgressions that are heterogeneous among NIL sub-lines, and associate heterogeneous introgressions with susceptibility to IDC. Using the CGH approach, introgression boundaries were refined and previously unknown introgressions were revealed. Furthermore, heterogeneous introgressions were identified within seven sub-lines of the IDC NIL “IsoClark.” This included three distinct introgression haplotypes linked to the major iron susceptible locus on chromosome 03. A phenotypic assessment of the seven sub-lines did not reveal any differences in IDC susceptibility, indicating that the genetic heterogeneity among the lines does not have a significant impact on the primary NIL phenotype. PMID:23630538

  14. Proton Spin Structure in the Resonance Region

    SciTech Connect

    F. R. Wesselmann; K. Slifer; S. Tajima; A. Aghalaryan; A. Ahmidouch; R. Asaturyan; F. Bloch; W. Boeglin; P. Bosted; C. Carasco; R. Carlini; J. Cha; J. P. Chen; M. E. Christy; L. Cole; L. Coman; D. Crabb; S. Danagoulian; D. Day; J. Dunne; M. Elaasar; R. Ent; H. Fenker; E. Frlez; L. Gan; D. Gaskell; J. Gomez; B. Hu; M. K. Jones; J. Jourdan; C. Keith; C. E. Keppel; M. Khandaker; A. Klein; L. Kramer; Y. Liang; J. Lichtenstadt; R. Lindgren; D. Mack; P. McKee; D. McNulty; D. Meekins; H. Mkrtchyan; R. Nasseripour; I. Niculescu; K. Normand; B. Norum; D. Pocanic; Y. Prok; B. Raue; J. Reinhold; J. Roche; D. Rohe; O. A. Rondon; N. Savvinov; B. Sawatzky; M. Seely; I. Sick; C. Smith; G. Smith; S. Stepanyan; L. Tang; G. Testa; W. Vulcan; K. Wang; G. Warren; S. Wood; C. Yan; L. Yuan; Junho Yun; Markus Zeier; Hong Guo Zhu

    2006-10-11

    The RSS collaboration has measured the spin structure functions g{sub 1} and g{sub 2} of the proton at Jefferson Lab using the lab's polarized electron beam, the Hall C HMS spectrometer and the UVa polarized solid target. The asymmetries A{sub parallel} and A{sub perp} were measured at the elastic peak and in the region of the nucleon resonances (1.085 GeV < W < 1.910 GeV) at an average four momentum transfer of Q{sup 2} = 1.3 GeV{sup 2}. The extracted spin structure functions and their kinematic dependence make a significant contribution in the study of higher-twist effects and polarized duality tests.

  15. Physical conditions in the narrow-line regions of M51 and NGC 4151

    NASA Astrophysics Data System (ADS)

    Bradley, Larry Daniel

    2004-04-01

    The relative proximity and luminosity of Seyfert galaxies allows for detailed studies of their spatially extended narrow-line regions (NLR), which are the largest structures in these active galactic nuclei (AGN) powered by the active nucleus. In this dissertation, I have used the high spatial resolution of the Hubble Space Telescope ( HST) and Very Large Array (VLA) to examine the physical conditions producing the kinematic and ionization structure observed in the NLR of two Seyfert galaxies, namely NGC 4151 and M51. The physical conditions in the NLR of NGC 4151 were investigated using medium spectral resolution HST/STIS slitless spectra and HST/Wide Field and Planetary Camera 2 (WFPC2) images. The slitless data allowed us to spatially map the velocity field of the complete inner NLR of NGC 4151. The observations show a biconical distribution of emission- line clouds with blueshifted radial velocities to the southwest of the nucleus and redshifted clouds to the northeast of the nucleus. The NLR clouds are distributed in at least two kinematic components, including a population of low-velocity (|v| < 400 km s-1), low-velocity dispersion (Δv < 130 km s-1 ) clouds and high-velocity (400 < |v| < 1700 km s-1), high-velocity dispersion (Δv ≥ 130 km s-1) clouds. Our results suggest that a wind-driven outflow is responsible for the acceleration of the NLR clouds. Within 3.'' 2 (˜200 pc) of the nucleus, the [O III] λ5007/Hβ emission-line ratio decreases approximately as r-0.3 . Because the ionization parameter is proportional to r -2 n-1, it appears that the density, n, of these NLR clouds falls off approximately as r-1.7. The physical conditions in the NLR of M51 were explored using long-slit spectra obtained with the Space Telescope Imaging Spectrograph (STIS) aboard HST and 8.4 GHz (3.6 cm) radio continuum observations obtained with the VLA. Emission-line diagnostics were employed for nine NLR clouds, which extend 2.'' 5 (102

  16. On the emitting region of X-ray fluorescent lines around Compton-thick AGN

    NASA Astrophysics Data System (ADS)

    Liu, Jiren

    2016-06-01

    X-ray fluorescent lines are unique features of the reflection spectrum of the torus when irradiated by the central active galactic nuclei (AGN). Their intrinsic line width can be used to probe the line-emitting region. Previous studies have focused on the Fe K α line at 6.4 keV, which is the most prominent fluorescent line. These studies, however, are limited by the spectral resolution of currently available instruments, the best of which is ˜1860 km s-1 afforded by the Chandra High-Energy Grating (HEG). The HEG spectral resolution is improved by a factor of 4 at 1.74 keV, where the Si K α line is located. We measured the full width at half-maximum of the Si K α line for Circinus, Mrk 3, and NGC 1068, which are 570 ± 240, 730 ± 320, and 320 ± 280 km s-1, respectively. They are 3-5 times smaller than those measured with the Fe K α line previously. It shows that the intrinsic widths of the Fe K α line are most likely to be overestimated. The measured widths of the Si K α line put the line-emitting region outside the dust sublimation radius in these galaxies. It indicates that for Compton-thick AGN, the X-ray fluorescence material are likely to be the same as the dusty torus emitting in the infrared band.

  17. Behaviour of oscillations in loop structures above active regions

    NASA Astrophysics Data System (ADS)

    Kolobov, D. Y.; Kobanov, N. I.; Chelpanov, A. A.; Kochanov, A. A.; Anfinogentov, S. A.; Chupin, S. A.; Myshyakov, I. I.; Tomin, V. E.

    2015-12-01

    In this study we combine the multiwavelength ultraviolet-optical (Solar Dynamics Observatory, SDO) and radio (Nobeyama Radioheliograph, NoRH) observations to get further insight into space-frequency distribution of oscillations at different atmospheric levels of the Sun. We processed the observational data on NOAA 11711 active region and found oscillations propagating from the photospheric level through the transition region upward into the corona. The power maps of low-frequency (1-2 mHz) oscillations reproduce well the fan-like coronal structures visible in the Fe IX 171 Å line. High frequency oscillations (5-7 mHz) propagate along the vertical magnetic field lines and concentrate inside small-scale elements in the umbra and at the umbra-penumbra boundary. We investigated the dependence of the dominant oscillation frequency upon the distance from the sunspot barycentre to estimate inclination of magnetic tubes in higher levels of sunspots where it cannot be measured directly, and found that this angle is close to 40° above the umbra boundaries in the transition region.

  18. Himalayan Sackung and Associations to Regional Structure

    NASA Astrophysics Data System (ADS)

    Shroder, J. F.; Bishop, M. P.; Olsenholler, J.

    2003-12-01

    Recognition of sackung slope failure or deep-seated, rock-slope deformation in the Himalaya has been rather limited, in part because: (1) many geoscientists do not recognize its characteristics; (2) large-scale aerial photographs and topographic maps used to identify the characteristic surficial, topographic manifestations of the failure type are commonly low-level state secrets in that region; and (3) no systematic survey for sackung has ever been made in the Himalaya. In the Pakistani-controlled, western Himalaya, some unconventional access to aerial photographs in the Kaghan and Nanga Parbat areas allowed first recognition of several characteristic ridge-top grabens and anti-slope scarps. Later release of declassified, stereo imagery from the CORONA and KEYHOLE satellite series enabled discovery of other examples in the K2 region. Comparison of mapped sackung failures with geologic base maps has demonstrated some coincidence of sackung with various structural trends, including synformal structures in upper thrust plates or along the traces of high-angle faults. In all probability these structural trends have provided plentiful ancillary planes of weakness along which gravitationally driven sackung is facilitated. Sackung failure in the Himalaya appears to be a spatially scale-dependent manifestation of a gravitational-collapse continuum of the brittle, upper crust, mainly involving mountain ridges. In contrast, gravitational collapse of the whole range may involve some similar failures but also include listric faulting, as well as subsidence movement into zones of ductility at depth. Temporal scale dependence of sackung may also be threshold dominated, wherein initial long-continued, slow failure ultimately leads to the commonly catastrophic rock-slope collapses recently recognized throughout the western Himalaya and now differentiated from their original mismapping as glacial moraines. Such sackung in Himalayan terrain undergoing active deglaciation from global

  19. REDSHIFTS, WIDTHS, AND RADIANCES OF SPECTRAL LINES EMITTED BY THE SOLAR TRANSITION REGION

    SciTech Connect

    Feldman, U.; Dammasch, I. E.; Doschek, G. A.

    2011-12-20

    A long-standing problem in understanding the physics of the transition region has been the ubiquitous redshifts of transition region ultraviolet spectral lines relative to chromospheric emission lines, a result known since the Skylab era. Extended spectral scans performed for various regions of the solar disk by the Solar Ultraviolet Measurements of Emitted Radiation spectrometer on the Solar and Heliospheric Observatory contain thousands of line profiles per study and allow a thorough investigation of the redshift phenomenon. In using these data from seven distinct disk areas made in lines spanning the chromosphere to coronal temperature range, we derive a relationship between Doppler wavelength shifts and radiances and a relationship between line widths and radiances. While chromospheric and coronal lines emitted by very bright plasmas may in some cases show pronounced redshifts, transition-region lines predominantly show redshifts everywhere in the quiet Sun and in active regions. In coronal holes, however, they display a reduced shift, which at times altogether disappears. The observations and the findings will be described, and possible explanations will be considered.

  20. Applied region restriction and noncausal algorithm for line process of image sequence

    NASA Astrophysics Data System (ADS)

    Kohno, Yasuhisa; Ebine, Takumi; Hamada, Nozomu

    2000-12-01

    The precise estimation of optical flow is a key technology in computer vision and moving image processing. Due to the inherent feature of apparent motion occlusion and uncovered phenomena, flow estimation is erroneous at moving object's boundary. The line field lattice process(i.e. Gibbs/Markov random field model of discontinuity) is a well-known solution to this problem.The binary-valued line is used to separate regions with respect to motion. This paper proposes two improvements to the conventional line field estimation process. One is to reduce the computational burden by the following idea. At the MAP estimation algorithm for region segmentation, the applied region of line setting is restricted solely within motion boundary area which is specified by thresholding the residue of optical flow constraints. The second improvement is to refine the estimation accuracy at the recursive minimization of energy function. Since the previous pel-recursive line estimation procedure uses causal scanning, it tends to give undesirable lines such as cracked or isolated lines.Our proposal algorithm adopts non-causal scan process. The effect of the proposed methods are examined for artificial and a real moving image. In consequence, only 14 of computational time of previous method is necessary to generate the line. In addition, undesirable line setting is effectively omitted.

  1. Three dimensional crustal structure beneath the Gulf of Aqaba region from regional earthquake tomography

    NASA Astrophysics Data System (ADS)

    El Khrepy, Sami; Koulakov, ivan; al-arifi, Nassir; Petrunin, Alexey

    2016-04-01

    Gulf of Aqaba is tectonically and seismically active according to up to date earthquake activity recorded by the National seismic network of Egypt and ISC. Aqaba Gulf is located at the southern part of the Dead Sea Rift at the Northern Red Sea Rift as a major component of the Sinai triple junction where the plate boundaries play an important role in the tectonic activity of this region. In this work we apply the regional earthquake tomography technique of Koulakov (2009) to the P and S waves arrival times . Checkerboard resolution test has been performed to estimate the resolution of the data used in the inversion. The synthetic tests reveled reasonable resolving for the main geologic structures. The results revealed three dimensional seismic structures of P and S waves beneath the Gulf of Ababa region for the first time. Consistent seismic velocity pattern is obtained for P and S seismic phases. Strong anomalies of high-velocity with abrupt change are observed coinciding with the northern Red sea coast lines. This new results indicate new perspective suggesting oceanic nature of the crust in the northern part of the Red Sea disagreeing with the Hypothesis of gradual stretching of the continental crust. Key words: Regional Seismic tomography, Gulf of Aqaba, Dead Sea Transform Fault, Northern Red Sea

  2. A structural model for multimodular NRPS assembly lines.

    PubMed

    Marahiel, Mohamed A

    2016-02-01

    This viewpoint article focuses on the structures of the dissected catalytic domains of non-ribosomal peptide synthetases (NRPSs) associated with substrate selection and activation (A domain), substrate shuttling among the active sites (PCP domain), peptide bond formation (C domain) and product release (TE domain). Structural details of these essential components of the NRPS machinery, integrated in a didomain (PCP-C) and an elongation module (C-A-PCP), were used to generate a model for a multimodular NRPS assembly line. PMID:26429504

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

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

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

  4. Seismogenic Structures in Hualien Region, eastern Taiwan

    NASA Astrophysics Data System (ADS)

    Kuochen, H.; Wu, Y.; Chen, Y.; Chen, R.; Kuo, Y.

    2004-12-01

    Due to extremely high seismicity and abundant tectonic-influenced geomorphic features, eastern Taiwan has long been known as a tectonically active region. The geological model of an on-going arc-continent collision was successfully proposed to explain the arrangement of the tectonic entities and their interaction. The convergent situation between Eurasia plate and Philippine Sea plate is believed still being existing because of no geomorphic evidence directly related to significant subsidence of the backbone mountain range. However, in the north of the Coastal Range, the Philippine Sea plate is moving northerly downward by the subduction mechanism. Accordingly the fault systems on-land and offshore should be significantly different. With an attempt to answer the puzzle mentioned above we therefore analyze the seismogenic structures in northern part of eastern Taiwan. We adopt the double difference (hypoDD) method to relocate earthquakes, apply the GOCAD (Geologic Computer Aided Design) to visually image the 3D subsurface structures, and determine the rupture plane by the Finite Dimension Source Model (FDSM) from first motion focal mechanisms. Selected earthquakes are (1) located within region between 121.2 ˜122° E and 23.5 ˜24.5° N; (2) M{ L }≥3; (3) and showing clearly P or S arrived time at least 6 recorded stations. Additionally, we determine the M { L } ≥4 focal mechanisms by using the first P wave polarities to examine the reliability of rupture planes determined above. A few of seismogenic structures are clearly identified in this study. Looking at the E-W profile, a major reverse fault dipping 60° to the east is found in depth of 20-40 km beneath the Coastal Range, which is probably the subsurface image of the plate boundary. On the other hand, within the Central Range several N-S oriented high-angle normal faults are found near the surface in the western part of the study area. The second one from the west reflects the subsurface extension of

  5. A contour-line color layer separation algorithm based on fuzzy clustering and region growing

    NASA Astrophysics Data System (ADS)

    Liu, Tiange; Miao, Qiguang; Xu, Pengfei; Tong, Yubing; Song, Jianfeng; Xia, Ge; Yang, Yun; Zhai, Xiaojie

    2016-03-01

    The color layers of contour-lines separated from scanned topographic map are the basis of contour-line extraction, but it is difficult to separate them well due to the color aliasing and mixed color problems. This paper will focus us on contour-line color layer separation and presents a novel approach for it based on fuzzy clustering and Single-prototype Region Growing for Contour-line Layer (SRGCL). The purpose of this paper is to provide a solution for processing scanned topographic maps on which contour-lines are abundant and densely distributed, for example, in the condition similar to hilly areas and mountainous regions, the contour-lines always occupy the largest proportion in linear features and the contour-line separation is the most difficult task. The proposed approach includes steps as follows. First step, line features are extracted from the map to reduce the interference from area features in fuzzy clustering. Second step, fuzzy clustering algorithm is employed to obtain membership matrix of pixels in the line map. Third step, based on the membership matrix, we obtain the most-similar prototype and the second-similar prototype of each pixel as the indicators of the pixel in SRGCL. The spatial relationship and the fuzzy similarity of color features are used in SRGCL to overcome the inaccurate classification of ambiguous pixels. The procedure focusing on single contour-line layer will improve the accuracy of contour-line segmentation result of SRGCL relative to general segmentation methods. We verified the algorithm on several USGS historical maps, the experimental results show that our algorithm produces contour-line color layers with good continuity and few noises, which verifies the improvement in contour-line color layer separation of our algorithm relative to two general segmentation methods.

  6. Mapping the Innermost Regions of Massive Stars in Formation through Millimeter Recombination Lines

    NASA Astrophysics Data System (ADS)

    Galván-Madrid, R.; Liu, H. B.; Hernández-Gómez, A.; Carrasco-González, C.

    2015-12-01

    Millimeter (mm) recombination lines (RLs) are intrinsically brighter than centimeter RLs and are free of pressure broadening. Mapping mm RLs in massive star formation (MSF) regions would trace the dynamics of the innermost volume where stars more massive than 10 or 20 ⊙ are forming. We report on our search using ALMA for mm RL emission in two MSF regions.

  7. VLBA Surveys of OH Masers in Star-forming Regions. I. Satellite Lines

    NASA Astrophysics Data System (ADS)

    Ruiz-Velasco, A. E.; Felli, D.; Migenes, V.; Wiggins, B. K.

    2016-05-01

    Using the Very Long Baseline Array we performed a high-resolution OH maser survey in Galactic star-forming regions (SFRs). We observed all the ground state spectral lines: the main lines at 1665 and 1667 MHz and the satellite lines at 1612 and 1720 MHz. Due to the exceptionality of finding satellite lines in SFRs, we will focus our discussion on those lines. In our sample of 41 OH maser sources, five (12%) showed the 1612 MHz line and ten (24%) showed the 1720 MHz line, with only one source showing both lines. We find that 1720 MHz emission is correlated with the presence of H ii regions, suggesting that this emission could be used to diagnose or trace high-mass star formation. We include an analysis of the possible mechanisms that could be causing this correlation as well as assessing the possible relationships between lines in our sample. In particular, the presence of magnetic fields seems to play an important role as we found Zeeman splitting in four of our sources (W75 N, W3(OH), W51 and NGC 7538). Our results have implications for current understanding of the formation of high-mass stars as well as on the masing processes present in SFRs.

  8. Medial Temporal Lobe Structures Contribute to On-Line Processing

    ERIC Educational Resources Information Center

    Warren, David

    2009-01-01

    For the last five decades, the medial temporal lobes have been generally understood to facilitate enduring representation of certain kinds of information. In particular, knowledge about the relations among items and concepts appears to rely on that region of the brain. Recent results suggest that those same structures also play a subtle role in…

  9. On Line Asymmetries in Quiet and Plage Regions on the Sun

    NASA Astrophysics Data System (ADS)

    Brandt, P. N.; Schroter, E. H.

    The centre-to-limb variation of the bisector shapes of the Fe I lines λ5576.1 Å and λ5250.2 Å is measured in quiet and plage regions on the sun. At disk centre the smaller curvature of the bisector in plage regions found in λ5576.1 Å and other lines by Kaisig and Schröter (1983) and in λ5250.6 Å by Livingston (1982) are essentially confirmed. While for λ5576.1 Å the differences in bisector shapes tend to decrease towards the limb they increase for λ5250.2 Å. Due to the lack of a wavelength reference no discrimination can be made between the red-shift of biscectors in the line-centres in plage-regions compared to non-active regions as found by Livingston (1982) and the corresponding relative blue-shift as reported by Kaisig and Schröter (1983).

  10. Electromagnetic response of buried cylindrical structures for line current excitation

    NASA Astrophysics Data System (ADS)

    Pajewski, Lara; Ponti, Cristina

    2013-04-01

    The Cylindrical-Wave Approach (CWA) rigorously solves, in the spectral domain, the electromagnetic forward scattering by a finite set of buried two-dimensional perfectly-conducting or dielectric objects [1]-[2]. In this technique, the field scattered by underground objects is represented in terms of a superposition of cylindrical waves. Use is made of the plane-wave spectrum [1] to take into account the interaction of such waves with the planar interface between air and soil, and between different layers eventually present in the ground [3]. Obstacles of general shape can be simulated through the CWA with good results, by using a suitable set of small circular-section cylinders [4]. Recently, we improved the CWA by facing the fundamental problem of losses in the ground [5]: this is of significant importance in remote-sensing applications, since real soils often have complex permittivity and conductivity, and sometimes also a complex permeability. While in previous works concerning the CWA a monochromatic or pulsed plane-wave incident field was considered, in the present work a different source of scattering is present: a cylindrical wave radiated by a line source. Such a source is more suitable to model the practical illumination field used in GPR surveys. The electric field radiated by the line current is expressed by means of a first-kind Hankel function of 0-th order. The theoretical solution to the scattering problem is developed for both dielectric and perfectly-conducting cylinders buried in a dielectric half-space. The approach is implemented in a Fortran code; an accurate numerical evaluation of the involved spectral integrals is performed, the highly-oscillating behavior of the homogeneous waves is correctly followed and evanescent contributions are taken into account. The electromagnetic field scattered in both air and ground can be obtained, in near- and far-field regions, for arbitrary radii and permittivity of the buried cylinders, as well as for

  11. Investigation of a stripline transmission line structure for gyromagnetic nonlinear transmission line high power microwave sources

    NASA Astrophysics Data System (ADS)

    Reale, D. V.; Parson, J. M.; Neuber, A. A.; Dickens, J. C.; Mankowski, J. J.

    2016-03-01

    A stripline gyromagnetic nonlinear transmission line (NLTL) was constructed out of yttrium iron garnet ferrite and tested at charge voltages of 35 kV-55 kV with bias fields ranging from 10 kA/m to 20 kA/m. Typically, high power gyromagnetic NLTLs are constructed in a coaxial geometry. While this approach has many advantages, including a uniform transverse electromagnetic (TEM) mode, simple interconnection between components, and the ability to use oil or pressurized gas as an insulator, the coaxial implementation suffers from complexity of construction, especially when using a solid insulator. By moving to a simpler transmission line geometry, NLTLs can be constructed more easily and arrayed on a single substrate. This work represents a first step in exploring the suitability of various transmission line structures, such as microstrips and coplanar waveguides. The resulting high power microwave (HPM) source operates in ultra high frequency (UHF) band with an average bandwidth of 40.1% and peak rf power from 2 MW to 12.7 MW.

  12. Investigation of a stripline transmission line structure for gyromagnetic nonlinear transmission line high power microwave sources.

    PubMed

    Reale, D V; Parson, J M; Neuber, A A; Dickens, J C; Mankowski, J J

    2016-03-01

    A stripline gyromagnetic nonlinear transmission line (NLTL) was constructed out of yttrium iron garnet ferrite and tested at charge voltages of 35 kV-55 kV with bias fields ranging from 10 kA/m to 20 kA/m. Typically, high power gyromagnetic NLTLs are constructed in a coaxial geometry. While this approach has many advantages, including a uniform transverse electromagnetic (TEM) mode, simple interconnection between components, and the ability to use oil or pressurized gas as an insulator, the coaxial implementation suffers from complexity of construction, especially when using a solid insulator. By moving to a simpler transmission line geometry, NLTLs can be constructed more easily and arrayed on a single substrate. This work represents a first step in exploring the suitability of various transmission line structures, such as microstrips and coplanar waveguides. The resulting high power microwave (HPM) source operates in ultra high frequency (UHF) band with an average bandwidth of 40.1% and peak rf power from 2 MW to 12.7 MW. PMID:27036802

  13. SERTS-95 Measurements of Wavelength Shifts in Coronal Emission Lines Across a Solar Active Region

    NASA Technical Reports Server (NTRS)

    Brosius, Jeffery W.; Thomas, Roger; Davila, Joseph

    1999-01-01

    We used slit spectra from the 1995 flight of Goddard Space Flight Center's Solar EUV Rocket Telescope and Spectrograph (SERTS-95) to measure wavelength shifts of coronal emission lines in the core of NOAA active region 7870 relative to its immediate surroundings (its "edge"). This method circumvents the unavailability of reliable laboratory rest wavelengths for the observed lines by using wavelengths from the edge spectrum as references. We derived the, SERTS-95 wavelength calibration from measurements of a post-flight laboratory spectrum containing 28 He II and Ne II EUV standard wavelengths known to high accuracy. Wavelength measurements for lines of He I, Ne III, and additional lines of Ne II in the laboratory calibration spectrum provide more accurate values than were previously available, enabling these lines also to serve as future calibration standards. Six solar lines were chosen for this study, namely, He II at 303.78 A, Fe XII at 193.51 A, Fe XIII at 202.05 A, Fe XIV at 211.33 A, Fe XV at 284.15 A, and Fe XVI at 335.41 A. Because these lines are free from known blends in the SERTS-95 spectra and are either intrinsically strong or near the SERTS-95 peak sensitivity, they are our most reliable lines for measuring relative wavelength shifts in the spatially resolved active region core spectra. The iron ions are the hottest ions ever used for this type of analysis. All six lines reveal statistically significant spatial variations in their measured relative wavelength shifts in the active region core, including mixtures of blueshifts and redshifts (each with maximum values corresponding to relative Doppler velocities approximately 15 km/s), indicating a dynamic, turbulent corona. For each of these lines we calculated weighted-average relative Doppler velocities from the wavelength shifts in the spatially resolved core spectra by weighting the shifts in the individual spatial pixels with their respective measurement uncertainties.

  14. Application of line scanning thermography for the detection of interlaminar disbonds in sandwich composite structures

    NASA Astrophysics Data System (ADS)

    Ley, Obdulia; Chung, Simon; Schutte, Jaco; Caiazzo, Anthony; Godinez, Valery; Bandos, Bruce

    2010-04-01

    An innovative Line Scanning Thermography (LST) inspection method is being developed as part of a Structural Damage Assessment System to access the health of in-service composite structures. The system utilizes a line heat source to thermally excite the surface inspected and an infrared detector to record the transient surface temperature variation and to detect regions of increased heat resistance associated to interlaminar disbonds, cracks and other imperfections found in composites structures. In this study our efforts towards the applications of LST for the analysis of carbon fiber sandwich composites will be discussed. The LST technique provides a quick and efficient methodology to scan wide areas rapidly. The scanning protocols developed for the detection of sub-surface disbonds (delamination) in composite sandwich parts will be presented. The results presented correspond to scans of test coupons with manufactured defects.

  15. Doppler shift of hot coronal lines in a moss area of an active region

    NASA Astrophysics Data System (ADS)

    Dadashi, N.; Teriaca, L.; Tripathi, D.; Solanki, S. K.; Wiegelmann, T.

    2012-12-01

    The moss is the area at the footpoint of the hot (3 to 5 MK) loops forming the core of the active region where emission is believed to result from the heat flux conducted down to the transition region from the hot loops. Studying the variation of Doppler shift as a function of line formation temperatures over the moss area can give clues on the heating mechanism in the hot loops in the core of the active regions. We investigate the absolute Doppler shift of lines formed at temperatures between 1 MK and 2 MK in a moss area within active region NOAA 11243 using a novel technique that allows determining the absolute Doppler shift of EUV lines by combining observations from the SUMER and EIS spectrometers. The inner (brighter and denser) part of the moss area shows roughly constant blue shift (upward motions) of 5 km s-1 in the temperature range of 1 MK to 1.6 MK. For hotter lines the blue shift decreases and reaches 1 km s-1 for Fe xv 284 Å (~2 MK). The measurements are discussed in relation to models of the heating of hot loops. The results for the hot coronal lines seem to support the quasi-steady heating models for nonsymmetric hot loops in the core of active regions.

  16. Understanding the Physical Conditions that Drive Line Emission in Nebular Regions of High-Redshift Galaxies

    NASA Astrophysics Data System (ADS)

    Zeimann, Gregory; Gebhardt, H.; Ciardullo, R.; Gronwall, C.; Hagen, A.

    2014-01-01

    We use the 3D-HST near-IR grism survey to study the physical conditions of the nebular regions within a statistically complete sample of ~ 300 emission-line selected star forming galaxies in the redshift range of 2.0 < z < 2.3. These spectra include the emission lines of oxygen ([O II] 3727, [O III] 5007), neon ([Ne III] 3869), and hydrogen (H-beta, H-gamma); when coupled with constraints on reddening and stellar mass derived from the objects' spectral energy distributions, these data allow us to explore parameters such as the systems' alpha-element abundances and ionization parameters. We try to reproduce these line ratios using theoretical models, such as CLOUDY, and compare line ratios with that of possible local analogs like Green Pea galaxies and Blue Compact Dwarfs. With our sample we can study any possible evolution in the physical conditions of star formation regions.

  17. Emission Line Spectra in the Soft X-Ray Region 20-75 (Angstrom)

    SciTech Connect

    Lepson, J K; Beiersdorfer, P; Chen, H; Behar, E; Kahn, S M

    2002-06-18

    As part of a project to complete a comprehensive catalogue of astrophysically relevant emission lines in support of new-generation X-ray observatories using the Lawrence Livermore electron beam ion traps EBIT-I and EBIT-II, we studied emission lines of argon and sulfur in the soft X-ray and extreme ultraviolet region. Here we present observations of Ar IX through Ar XVI and S VII through S XIV between 20 and 75 {angstrom} to illustrate our work.

  18. Emission Line Spectra in the Soft X-ray Region 20 - 75 Angstroms

    NASA Technical Reports Server (NTRS)

    Lepson, J. K.; Beiersdorfer, P.; Chen, H.; Behar, E.; Kahn, S. M.

    2002-01-01

    As part of a project to complete a comprehensive catalogue of astrophysically relevant emission lines in support of new-generation X-ray observatories using the Lawrence Livermore electron beam ion traps EBIT-I and EDIT-II, emission lines of argon and sulfur in the soft X-ray and extreme ultraviolet region were studied. Observations of Ar IX through Ar XVI and S VII through S XIV between 20 and 75 Angstrom are presented to illustrate our work.

  19. Spectral Line Profile Analysis Using Higher Diffraction Order in Vacuum Ultraviolet Region

    SciTech Connect

    Machida, M.; Daltrini, A. M.; Severo, J. H. F.; Nascimento, I. C.; Sanada, E. K.; Elizondo, J. I.; Kuznetsov, Y. K.; Galvao, R. M. O.

    2008-04-07

    Using a one meter VUV spectrometer and a MCP coupled to a CCD detector on TCABR tokamak, ion temperatures from impurity species have been measured and much better spectral resolution was obtained using higher order diffraction lines. Due to very small Doppler effect in the VUV region compared to large instrumental broadening, ion temperatures obtained from first order diffraction present large errors. The use of second, third and fourth order diffraction emissions increases the line broadening and results in lower error temperature measurements.

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

    NASA Technical Reports Server (NTRS)

    Kallman, T.; Mushotzky, R.

    1985-01-01

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

  1. Improved line parameters for ozone bands in the 10-micron spectral region

    NASA Technical Reports Server (NTRS)

    Flaud, Jean-Marie; Camy-Peyret, Claude; Rinsland, Curtis P.; Smith, Mary Ann H.; Devi, Malathy V.

    1990-01-01

    A complete update of spectroscopic line parameters for the 10-micron bands of ozone is reported. The listing contains calculated positions, intensities, lower state energies, and air- and self-broadened halfwidths of more than 53,000 lines. The results have been generated using improved spectroscopic parameters obtained in a number of recent high resolution laboratory studies. A total of eighteen bands of (O-16)3 (sixteen hot bands plus the nu(1) and nu(3) fundamentals) are included along with the nu(1) and nu(3) fundamentals of both (O-16)(O-16)(O-18) and (O-16)(O-18)(O-16). As shown by comparisons of line-by-line simulations with 0.003/cm resolution balloon-borne stratospheric solar spectra, the new parameters greatly improve the accuracy of atmospheric calculations in the 10-micron region, especially for the isotopic (O-16)(O-16)(O-18) and (O-16)(O-18)(O-16) lines.

  2. Silicon X-ray line emission from solar flares and active regions

    NASA Technical Reports Server (NTRS)

    Parkinson, J. H.; Wolff, R. S.; Kestenbaum, H. L.; Ku, W. H.-M.; Lemen, J. R.; Long, K. S.; Novick, R.; Suozzo, R. J.; Weisskopf, M. C.

    1978-01-01

    New observations of solar flare and active region X-ray spectra obtained with the Columbia University instrument on OSO-8 are presented and discussed. The high sensitivity of the graphite crystal panel has allowed both line and continuum spectra to be served with moderate spectral resolution. Observations with higher spectral resolution have been made with a panel of pentaerythritol crystals. Twenty-nine lines between 1.5 and 7.0 A have been resolved and identified, including several dielectronic recombination satellite lines to Si XIV and Si XIII lines which have been observed for the first time. It has been found that thermal continuum models specified by single values of temperature and emission measure have fitted the data adequately, there being good agreement with the values of these parameters derived from line intensity ratios.

  3. Constraining UV continuum slopes of active galactic nuclei with cloudy models of broad-line region extreme-ultraviolet emission lines

    SciTech Connect

    Moloney, Joshua; Michael Shull, J. E-mail: michael.shull@colorado.edu

    2014-10-01

    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 λ765, O II λ833, and O III λ834 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 {sub H} ≥ 10{sup 12} cm{sup –3}) and hydrogen ionizing photon fluxes (Φ{sub H} ≥ 10{sup 22} cm{sup –2} s{sup –1}).

  4. The continuum and narrow-line region of the narrow-line Seyfert 1 galaxy Mrk 766

    NASA Astrophysics Data System (ADS)

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

    2005-02-01

    We present the first spectroscopic observations in the interval 0.8-4.0 μm, complemented with existing Hubble Space Telescope ultraviolet (UV) and optical spectroscopy, of the narrow-line Seyfert 1 galaxy Mrk 766. The near-infrared spectrum is characterized by numerous permitted lines of HI, HeI, HeII and FeII, and forbidden lines of [SII], [SIII] and [FeII] among others. Highly ionized species such as [SiIX], [SiX], [SIX] and [MgVII] are also observed. The continuum emission has a complex shape, with contributions from the central engine, circumnuclear stellar population and dust. This last component is demonstrated by the presence of an excess of emission peaking at 2.25 μm, well fitted by a blackbody function with Tbb= 1200 K. That temperature is close to the evaporation temperature of graphite grains. As such, it provides strong evidence of hot dust, probably very close to the nucleus. Consistent modelling of the line spectrum and the broad-band continuum by composite models, which account for the photoionizing flux of the central engine and shocks, shows that shock velocities range between 100 and 500 km s-1, the pre-shock densities between 100 and 1000 cm-3 and the radiation fluxes from the active centre between 109 and 5 × 1012 photon cm-2 s-1 eV-1 at 1 Ryd with spectral indices αUV=-1.5 and αX=-0.4. Adopting silicate grains, dust-to-gas ratios are between 10-6 and 4 × 10-4 by mass. The emitting clouds are at an average distance of 160 pc from the centre, with high-velocity clouds closer and low-velocity clouds further from the centre. The N/H relative abundance deduced from the fit of the [NII] 6548+/[OIII] 5007+ line ratio could be twice the solar value. On the other hand, Fe is depleted from the gaseous phase by a factor >2, most probably trapped into grains. Ratios of calculated to observed line ratios to Hβ indicate an average contribution of the broad-line region to the observed Hβ of approximately 40 per cent.

  5. Diagnostics of the κ-distribution using Si III lines in the solar transition region

    NASA Astrophysics Data System (ADS)

    Dzifčáková, E.; Kulinová, A.

    2011-07-01

    Aims: The solar transition region satisfies the conditions for appearance of the non-thermal κ-distribution. We aim to prove the occurrence of the non-thermal κ-distribution in the solar transition region and diagnose its parameters. Methods: The intensity ratios of Si iii lines observed by SUMER in 1100-1320 Å region do not correspond to the line ratios computed under the assumption of the Maxwellian electron distribution. We computed a set of synthetic Si iii spectra for the electron κ-distributions with different values of the parameter κ. We had to include the radiation field in our calculations to explain the observed line ratios. We propose diagnostics of the parameter κ and other plasma parameters and analyze the effect of the different gradient of differential emission measures (DEM) on the presented calculations. Results: The used line ratios are sensitive to T, density and the parameter κ. All these parameters were determined from the SUMER observations for the coronal hole (CH), quiet Sun (QS) and active region (AR) using our proposed diagnostics. A strong gradient of DEM influences the diagnosed parameters of plasma. The essential contributions to the total line intensities do not correspond to single T but a wider range of T, and they originate in different atmospheric layers. The amount of the contributions from these atmospheric layers depends on the gradient of DEM and the shape of the electron distribution function. Conclusions: The κ-distribution is able to explain the observed Si iii line spectrum in the transition region. The degree of non-thermality increases with the activity of the solar region, it is lower for CH and higher for the AR. The DEM influences the diagnosed T and Ne but it has only little effect on the diagnostics of the parameter κ.

  6. A Line Defect Structure in Soft-Mode Turbulence

    NASA Astrophysics Data System (ADS)

    Nur Qomaru Zaman, Rinto A.; Ueki, Tatsuhiro; Hidaka, Yoshiki; Tribelsky, Michael I.; Kai, Shoichi

    2010-03-01

    Defects have been much investigated in various physical systems. The property and symmetry in a system can be reflected by the existence of defects. For example in spin models, symmetries in the 2D XY and 2D Ising models generate point and line defects, respectively. In the soft-mode turbulence (SMT) in electroconvection of homeotropic nematic systems which is a kind of spatiotemporal chaos induced by nonlinear interaction between the Nambu-Goldstone modes and the convective modes, a curious line structure called blackline has been discovered. We measured the density of the blackline as a function of control parameters, ac voltage and frequency. By detailed observations and analysis, it is clarified that the blackline is a structure of the nematic director in the x-y plane and includes a sequence of point defects. We discussed similarity with the density of the blackline and that of the point defect in the conventional 2D XY model. The occurrence of this type of defects is only due to the symmetry in the SMT and independent of the properties of fluctuations.

  7. Kinetic signatures of the region surrounding the X line in asymmetric (magnetopause) reconnection

    NASA Astrophysics Data System (ADS)

    Shay, M. A.; Phan, T. D.; Haggerty, C. C.; Fujimoto, M.; Drake, J. F.; Malakit, K.; Cassak, P. A.; Swisdak, M.

    2016-05-01

    Kinetic particle-in-cell simulations are used to identify signatures of the electron diffusion region (EDR) and its surroundings during asymmetric magnetic reconnection. A "shoulder" in the sunward pointing normal electric field (EN > 0) at the reconnection magnetic field reversal is a good indicator of the EDR and is caused by magnetosheath electron meandering orbits in the vicinity of the X line. Earthward of the X line, electrons accelerated by EN form strong currents and crescent-shaped distribution functions in the plane perpendicular to B. Just downstream of the X line, parallel electric fields create field-aligned crescent electron distribution functions. In the immediate upstream magnetosheath, magnetic field strength, plasma density, and perpendicular electron temperatures are lower than the asymptotic state. In the magnetosphere inflow region, magnetosheath ions intrude resulting in an Earthward pointing electric field and parallel heating of magnetospheric particles. Many of the above properties persist with a guide field of at least unity.

  8. A region of intense plasma wave turbulence on auroral field lines

    NASA Technical Reports Server (NTRS)

    Gurnett, D. A.; Frank, L. A.

    1976-01-01

    This report presents a detailed study of the plasma wave turbulence observed by HAWKEYE-1 and IMP-6 on high latitude auroral field lines and investigates the relationship of this turbulence to magnetic field and plasma measurements obtained in the same region.

  9. NUTRITIONAL VALUES OF SOYBEAN BREEDING LINES GROWN IN THE DELMARVA REGION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soybean is an important crop grown in the Delaware, Maryland, and Virginia (Delmarva) region for its protein and oil contents. Fifteen breeding lines and cultivars of soybean were evaluated for their seed yield, protein and oil content. Genotypes D358B4009, M3583009 and Stalwart provided 3,295, 2,...

  10. 3D Modeling of Forbidden Line Emission in the Binary Wind Interaction Region of Eta Carinae

    NASA Technical Reports Server (NTRS)

    Madura, Thomas; Gull, T. R.; Owocki, S.; Okazaki, A. T.; Russell, C. M. P.

    2010-01-01

    We present recent work using three-dimensional (3D) Smoothed Particle Hydrodynamics (SPH) simulations to model the high ([Fe III], [Ar III], [Ne III] and [S III]) and low ([Fe II], [Ni II]) ionization forbidden emission lines observed in Eta Carinae using the HST/STIS. These structures are interpreted as the time-averaged, outer extensions of the primary wind and the wind-wind interaction region directly excited by the FUV of the hot companion star of this massive binary system. We discuss how analyzing the results of the 3D SPH simulations and synthetic slit spectra and comparing them to the spectra obtained with the HST/STIS helps us determine the absolute orientation of the binary orbit and helps remove the degeneracy inherent to models based solely on the observed RXTE X-ray light curve. A key point of this work is that spatially resolved observations like those with HST/STIS and comparison to 3D models are necessary to determine the alignment or misalignment of the orbital angular momentum axis with the Homunculus, or correspondingly, the alignment of the orbital plane with the Homunculus skirt.

  11. Emission line spectra of S VII ? S XIV in the 20 ? 75 ? wavelength region

    SciTech Connect

    Lepson, J K; Beiersdorfer, P; Behar, E; Kahn, S M

    2004-08-06

    As part of a larger project to complete a comprehensive catalogue of astrophysically relevant emission lines in support of new-generation X-ray observatories using the Lawrence Livermore electron beam ion traps EBIT-I and EBIT-II, the authors present observations of sulfur lines in the soft X-ray and extreme ultraviolet regions. The database includes wavelength measurements with standard errors, relative intensities, and line assignments for 127 transitions of S VII through S XIV between 20 and 75 {angstrom}. The experimental data are complemented with a full set of calculations using the Hebrew University Lawrence Livermore Atomic Code (HULLAC). A comparison of the laboratory data with Chandra measurements of Procyon allows them to identify S VII-S XI lines.

  12. Evaporation, viscous flow, and electrostatic interaction of charged interfaces in the apparent contact line region

    NASA Astrophysics Data System (ADS)

    Ketelaar, Christiaan; Ajaev, Vladimir S.

    2015-11-01

    We consider evaporation of an aqueous solution near an apparent contact line separating a macroscopically dry area of a heated solid substrate and a constant-curvature meniscus far away from the substrate. Viscous flow, described by a lubrication-type model, is coupled to the interaction of electrical double layers formed near the solid-liquid and liquid-vapor interfaces. The electrostatic interaction is described using the nonlinear Poisson-Boltzmann equation and is shown to affect both normal and shear stress balances at the deformable interface. For steady configurations, we find that the apparent contact line region becomes wider and the total evaporation rate there increases as the substrate potential is increased. Motion of the apparent contact line in response to changes in the substrate temperature is also investigated. The contact line speed is found to increase when the electrostatic effects are incorporated into the model.

  13. The 51.8 micron (0 3) line emission observed in four galactic H 2 regions

    NASA Technical Reports Server (NTRS)

    Melnick, G.; Gull, G. E.; Harwit, M.

    1978-01-01

    The (0 III) 51.8 microns line from four H II regions, M42, M17, W51 and NGC 6375A was detected. Respective line strengths are 7 x 10 to the minus 15 power, 1.0 x 10 to the minus 14 power, 2.1 x 10 to the minus 15 power and 2.6 x 10 to the minus 15 power watt cm/2. Observations are consistent with previously reported line position and place the line at 51.80 + or 0.05 micron. When combined with the 88.35 microns (0 III) reported earlier, clumping seems to be an important factor in NGC 6375A and M42 and to a lesser extent in W51 and M17. The combined data also suggest an (0 III) abundance of approximately 3 x 0.0001 sub n e' a factor of 2 greater than previously assumed.

  14. 51.8 micron forbidden O III line emission observed in four galatic H II regions

    NASA Technical Reports Server (NTRS)

    Melnick, G.; Gull, G. E.; Harwit, M.

    1979-01-01

    The 51.8-micron forbidden O III line has been detected in four H II regions: M42, M17, W51, and NGC 6357A. The respective line strengths are 7 x 10 to the -15th, 1.0 x 10 to the -14th, 2.1 x 10 to the -15th, and 2.6 x 10 to the -15th W/sq cm. The observations are consistent with a previously reported line position and place the line at 51.80 + or - 0.05-micron. When combined with the 88.35-micron forbidden O III observations reported earlier, clumpiness is found to be an important factor in NGC 6357A and M42 and nonnegligible in W51 and M17. The combined data also suggest an O III abundance of about 0.0003 times the electron density, which is a factor of 2 greater than a number of investigators have reported.

  15. Radiative and magnetic properties of solar active regions. I. Global magnetic field and EUV line intensities

    NASA Astrophysics Data System (ADS)

    Fludra, A.; Ireland, J.

    2008-05-01

    Context: The relationships between the photospheric magnetic flux and either the X-ray or extreme ultraviolet emission from the solar atmosphere have been studied by several authors. Power-law relations have been found between the total magnetic flux and X-ray flux or intensities of the chromospheric, transition region, and coronal emission lines in solar active regions. These relations were then used to infer the mechanism of the coronal heating. Aims: We derive accurate power laws between EUV line intensities and the total magnetic flux in solar active regions and discuss their applications. We examine whether these global power laws are capable of providing the diagnostics of the coronal heating mechanism. Methods: This analysis is based on EUV lines recorded by the Coronal Diagnostic Spectrometer (CDS) on SOHO for 48 solar active regions, as they crossed the central meridian in years 1996-1998. Four spectral lines are used: He I 584.3 Å (3×104 K), O V 629.7 Å (2.2×105 K), Mg IX 368.06 Å (9.5×105 K), and Fe XVI 360.76 Å (2.0×106 K). In particular, the Fe XVI 360.76 Å line, seen only in areas of enhanced heating in active regions or bright points, has not been used before for this analysis. Results: Empirical power laws are established between the total active region intensity in the lines listed above and the total magnetic flux. We demonstrate the usefulness of some spatially integrated EUV line intensities, I_T, as a proxy for the total magnetic flux, Φ, in active regions. We point out the approximate, empirical nature of the I_T-Φ relationships and discuss the interpretation of the global power index. Different power index values for transition region and coronal lines are explained by their different dependence on pressure under the assumption of hydrostatic loop models. However, the global power laws are dominated by the size of the active regions, and we demonstrate for the first time the difficulties in uniquely relating the power index in the

  16. Highlight: Structural Insights into Nonribosomal Peptide Enzymatic Assembly Lines

    PubMed Central

    Koglin, Alexander

    2009-01-01

    Nonribosomal peptides have a variety of medicinal activities including activity as antibiotics, antitumor drugs, immunosuppressives, and toxins. Their biosynthesis on multimodular assembly lines as a series of covalently tethered thioesters, in turn covalently attached on pantetheinyl arms on carrier protein way stations, reflects similar chemical logic and protein machinery to fatty acid and polyketide biosynthesis. While structural information on excised or isolated catalytic adenylation (A), condensation (C), peptidyl carrier protein (PCP) and thioesterase (TE) domains had been gathered over the past decade, little was known about how the NRPS catalytic and carrier domains interact with each other both within and across elongation or termination modules. This highlight reviews recent breakthrough achievements in both X-ray and NMR spectroscopic studies that illuminate the architecture of NRPS PCP domains, PCP-containing didomain-fragments and of a full termination module (C-A-PCP-TE). PMID:19636447

  17. Improved spectroscopic line list of methyl chloride in the 1900-2600 cm-1 spectral region

    NASA Astrophysics Data System (ADS)

    Nikitin, A. V.; Dmitrieva, T. A.; Gordon, I. E.

    2016-07-01

    Parameters of line positions and line intensities up to 2×10-25 cm-1/(molecule cm-2) for 12CH335Cl and 12CH337Cl were retrieved from the Fourier transform spectra in the range of 1900-2600 cm-1. Line intensities were scaled with measurements from literature. Measured line positions and intensities were treated using global effective Hamiltonian and dipole moment model. The RMS of intensity fitting was 7.4% for 12CH335Cl and 6.6% for 12CH337Cl. List of positions and intensities were calculated for 22,098 and 21,014 lines between 1900 and 2600 cm-1 for 12CH335Cl and 12CH337Cl, respectively. Updated intensities allow extending assignments. The new line list of positions and intensities for both isotopologues in this spectral region was calculated. The calculations from the line list of this work have been compared with values from the HITRAN2012 database and PNNL spectra.

  18. Comparative analysis of the 100 kb region containing the Pi-k(h) locus between indica and japonica rice lines.

    PubMed

    Kumar, S P; Dalai, V; Singh, N K; Sharma, T R

    2007-02-01

    We have recently cloned a pathogen inducible blast resistance gene Pi-k(h) from the indica rice line Tetep using a positional cloning approach. In this study, we carried out structural organization analysis of the Pi-k(h) locus in both indica and japonica rice lines. A 100 kb region containing 50 kb upstream and 50 kb downstream sequences flanking to the Pi-k(h) locus was selected for the investigation. A total of 16 genes in indica and 15 genes in japonica were predicted and annotated in this region. The average GC content of indica and japonica genes in this region was 53.15% and 49.3%, respectively. Both indica and japonica sequences were polymorphic for simple sequence repeats having mono-, di-, tri-, tetra-, and pentanucleotides. Sequence analysis of the specific blast resistant Pi-k(h) allele of Tetep and the susceptible Pi-k(h) allele of the japonica rice line Nipponbare showed differences in the number and distribution of motifs involved in phosphorylation, resulting in the resistance phenotype in Tetep. PMID:17572362

  19. The inner region of the moving contact line - diffusive and nanoscale models

    NASA Astrophysics Data System (ADS)

    Nold, Andreas; Sibley, David N.; Goddard, Ben D.; Kalliadasis, Serafim

    2015-11-01

    Much of the work within the Complex Multiphase Systems group at Imperial College London for the last number of years has been to understand the moving contact line problem. In, it was shown that contrary to the classical asymptotic theory at the moving contact line, the intermediate region is in fact an overlap region between the inner and the outer regions. Here, we investigate the inner region independently for the Navier-Stokes/ Cahn-Hilliard (NS/CH) model for binary fluids, as well as dynamic density functional theory (DDFT) for a simple fluid. We show that in the NS/CH model, the overlap region is recovered in the sharp-interface limit, and we link the slip length to the mobility of the system. In contrast, DDFT, which is based on statistical mechanics of fluids, allows to incorporate nanoscale details. Results are presented for advancing and receding contact lines for a wide range of contact angles. The numerical method employs spectral methods in an unbounded domain along the surface. Advantages are discussed, both for differential and integral DDFT equations. We acknowledge financial support from ERC Advanced Grant No. 247031 and Imperial College through a DTG International Studentship.

  20. Structure Prediction and Analysis of DNA Transposon and LINE Retrotransposon Proteins*

    PubMed Central

    Abrusán, György; Zhang, Yang; Szilágyi, András

    2013-01-01

    Despite the considerable amount of research on transposable elements, no large-scale structural analyses of the TE proteome have been performed so far. We predicted the structures of hundreds of proteins from a representative set of DNA and LINE transposable elements and used the obtained structural data to provide the first general structural characterization of TE proteins and to estimate the frequency of TE domestication and horizontal transfer events. We show that 1) ORF1 and Gag proteins of retrotransposons contain high amounts of structural disorder; thus, despite their very low conservation, the presence of disordered regions and probably their chaperone function is conserved. 2) The distribution of SCOP classes in DNA transposons and LINEs indicates that the proteins of DNA transposons are more ancient, containing folds that already existed when the first cellular organisms appeared. 3) DNA transposon proteins have lower contact order than randomly selected reference proteins, indicating rapid folding, most likely to avoid protein aggregation. 4) Structure-based searches for TE homologs indicate that the overall frequency of TE domestication events is low, whereas we found a relatively high number of cases where horizontal transfer, frequently involving parasites, is the most likely explanation for the observed homology. PMID:23530042

  1. Kinetic Structure of the Reconnection Diffusion Region

    NASA Astrophysics Data System (ADS)

    Khotyaintsev, Yuri

    2016-04-01

    We present high-resolution multi-spacecraft observations of electromagnetic fields and particle distributions by Magnetospheric Multiscale (MMS) mission throughout a reconnection layer at the sub-solar magnetopause. We study which terms in the generalized Ohm's law balance the observed electric field throughout the region. We also study waves and particle distribution functions in order to identify kinetic boundaries created due to acceleration and trapping of electrons and ions as well as mixing of electron populations from different sides of the reconnecting layer. We discuss the interplay between particles, waves, and DC electric and magnetic fields, which clearly demonstrates kinetic and multi-scale nature of the reconnection diffusion region.

  2. Radial transmission line analysis of multi-layer structures

    SciTech Connect

    Hahn, H.; Hammons, L.

    2011-03-28

    The analysis of multi-layer beam tubes is a standard problem and involves axially propagating waves. This treatment is ill suited to a short multi-layer structure such as the present example of a ferrite covered ceramic break in the beam tube at the ERL photo-cathode electron gun. This paper demonstrates that such structure can better be treated by radial wave propagation. The theoretical method is presented and numerical results are compared with measured network analyser data and Microwave Studio generated simulations. The results confirm the concept of radial transmission lines as a valid analytical method. An Energy Recovery Linac (ERL) is being constructed at this laboratory for the purpose of research towards an envisioned Electron Ion Collider. One of the pertinent topics is damping of Higher Order Modes (HOM). In this ERL, the damping is provided by ferrite absorbers in the beam tube. A modified version thereof, a ceramic break surrounded by ferrite, is planed for the superconducting electron gun. The damper here is located at room temperature just outside of the gun. If used in a cavity chain, the ceramic break is in the vacuum tube at helium temperature whereas the ferrite is moved into the cryostat insulating vacuum allowing higher temperatures. The general properties of the ferrite HOM dampers have been published but are more detailed in this paper.

  3. Line Parameters of Carbon Dioxide in the 4850 CM-1 Region

    NASA Astrophysics Data System (ADS)

    Benner, D. Chris; Devi, V. Malathy; Nugent, Emily; Sung, Keeyoon; Brown, Linda R.; Miller, Charles E.; Toth, Robert A.

    2011-06-01

    The spectral region near 4850 Cm-1 is used to monitor atmospheric carbon dioxide, but current accuracies of the line intensities and line shape coefficients do not permit carbon dioxide mixing ratios to be obtained to 1 ppm (about one part in 400). To improve the line parameters, we are remeasuring the prominent CO2 bands in this region specifically to characterize the non-Voigt effects of line mixing and speed dependence at room temperature. The laboratory spectra of air- and self-broadened CO2 have been recorded at a variety of pressures, path lengths, mixing ratios and resolutions (0.005 to 0.01 Cm-1) with two different Fourier transform spectrometers (the McMath-Pierce FTS at Kitt Peak and a Bruker 125 HR FTS at JPL). The line parameters of some 2000 transitions are being derived by simultaneous multispectrum fitting using a few dozen spectra encompassing a 230 Cm-1 wide spectral interval. The rovibrational constants for line positions and the band intensities and Herman-Wallis coefficients are being retrieved directly from the spectra, rather than floating positions and intensities individually. Self and foreign Lorentz widths and pressure shifts are being determined for the stronger bands while non-Voigt coefficients describing line mixing and speed dependence are being obtained for at least one of the strongest bands. D. Chris Benner, C. P. Rinsland, V. M. Devi, M. A. H. Smith, and D. A. Atkins, JQSRT 1995;53:705-21. V. M. Devi, D. Chris Benner, L. R. Brown, C. E. Miller, and R. A. Toth, J. Mol. Spectrosc. 2007;245:52-80. Part of the research described in this paper was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contracts and cooperative agreements with the National Aeronautics and Space Administration. Support for the work at William and Mary was provided by contracts with JPL.

  4. Spectra of High-Ionization Seyfert 1 Galaxies: Implications for the Narrow-Line Region

    NASA Astrophysics Data System (ADS)

    Moore, David; Cohen, Ross D.; Marcy, Geoffrey W.

    1996-10-01

    We present line profiles and profile parameters for the narrow-line regions (NLRs) of six Seyfert I galaxies with high-ionization lines: MCG 8-11-I1, Mrk 79, Mrk 704, Mrk 841, NGC 4151, and NGC 5548. The sample was chosen primarily with the goal of obtaining high-quality [Fe VII] λ6087 and, when possible, [Fe X] λ6374 profiles to determine if these lines are more likely formed in a physically distinct coronal line region" or are formed throughout the NLR along with lines of lower critical density (n_cr_) and/or ionization potential (IP). We discuss correlations of velocity shift and width with n_cr_ and IP. In some objects, lines of high IP and/or n_cr_ are systematically broader than those of low IP/n_cr_. Of particular interest, however, are objects that show no correlations of line width with either IP or n_cr_ In these objects, lines of high and low IP/n_cr_ are remarkably similar, which is difficult to reconcile with the classical picture of the NLR, in which lines of high and low IP/n_cr_ are formed in physically distinct regions. We argue for similar spatial extents for the flux in lines with similar profiles. Here, as well as in a modeling-oriented companion paper (Paper II), we develop further an idea suggested by Moore & Cohen that objects that do and do not show line width correlations with IP/n_cr_ can both be explained in terms of a single NLR model with only a small difference in the cloud column density distinguishing the two types of object. Overall, our objects do not show correlations between the full width at half- maximum (FWHM) and IP and/or n_cr_. The width must be defined by a parameter that is sensitive to extended profile wings in order for the correlations to result. In Paper II, we present models in which FWHM correlations with IP and/or n_cr_ result only after simulating the lower spectral resolution used in previous observational studies. The models that simulate the higher spectral resolution of our observational study produce line

  5. Spectra of High-Ionization Seyfert 1 Galaxies: Implications for the Narrow-Line Region

    NASA Technical Reports Server (NTRS)

    Moore, David; Cohen, Ross D.; Marcy, Geoffrey W.

    1996-01-01

    We present line profiles and profile parameters for the Narrow-Line Regions (NLRs) of six Seyfert 1 galaxies with high-ionization lines: MCG 8-11-11, Mrk 79, Mrk 704, Mrk 841, NGC 4151, and NGC 5548. The sample was chosen primarily with the goal of obtaining high-quality [Fe VII] lambda6087 and, when possible, [Fe X] lambda6374 profiles to determine if these lines are more likely formed in a physically distinct 'coronal line region' or are formed throughout the NLR along with lines of lower critical density (n(sub cr)) and/or Ionization Potential (IP). We discuss correlations of velocity shift and width with n(sub cr) and IP. In some objects, lines of high IP and/or n(sub cr) are systematically broader than those of low IP/n(sub cr). Of particular interest, however, are objects that show no correlations of line width with either IP or n(sub cr). In these objects, lines of high and low IP/n(sub cr), are remarkably similar, which is difficult to reconcile with the classical picture of the NLR, in which lines of high and low IP/n(sub cr) are formed in physically distinct regions. We argue for similar spatial extents for the flux in lines with similar profiles. Here, as well as in a modeling-oriented companion paper, we develop further an idea suggested by Moore & Cohen that objects that do and do not show line width correlations with IP/n(sub cr) can both be explained in terms of a single NLR model with only a small difference in the cloud column density distinguishing the two types of object. Overall, our objects do not show correlations between the Full Width at Half-Maximum (FWHM) and IP and/or n(sub cr). The width must be defined by a parameter that is sensitive to extended profile wings in order for the correlations to result. We present models in which FWHM correlations with IP and/or n(sub cr) result only after simulating the lower spectral resolution used in previous observational studies. The models that simulate the higher spectral resolution of our

  6. Temperature Measurements in the Solar Transition Region Using N III Line Intensity Ratios

    NASA Technical Reports Server (NTRS)

    Doron, R.; Doschek, G. A.; Laming, J. M.; Feldman, U.; Bhatia, A. K.

    2003-01-01

    UV emission from B-like N and O ions a rather rare opportunity for recording spectral lines in a narrow wavelength range that can potentially be used to derive temperatures relevant to the solar transition region. In these ions, the line intensity ratios of the type (2s2p(sup 2) - 2p(sup 3)) / (2s(sup 2)2p - 2s2p(sup 2)) are very sensitive to the electron temperature. Additionally, the lines involving the ratios fall within a range of only - 12 A; in N III the lines fall in the 980 - 992 A range and in O IV in the 780 - 791 A range. In this work, we explore the use of these atomic systems, primarily in N III, for temperature diagnostics of the transition region by analyzing UV spectra obtained by the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer flown on the Solar and Heliospheric Observatory (SOHO). The N III temperature-sensitive line ratios are measured in more than 60 observations. Most of the measured ratios correspond to temperatures in the range 5.7x10(exp 4) - 6.7x10(exp 4) K. This range is considerably lower than the calculated temperature of maximum abundance of N III, which is approx. 7.6x10(exp 4) K. Detailed analysis of the spectra further indicates that the measured ratios are probably somewhat overestimated due to resonant scattering effects in the 2s(sup 2)2p - 2s2p(sup 2) lines and small blends in the 2s2p(sup 2) - 2p3 lines. Actual lower ratios would only increase the disagreement between the ionization balance calculations and present temperature measurements based on a collisional excitation model. In the case of the O IV spectra, we determined that due to the close proximity in wavelength of the weak line (2s2p(sup 2)-2p3 transitions) to a strong Ne VIII line, sufficiently accurate ratio measurements cannot be obtained. Subject headings: atomic data --- atomic processes --- Sun: transition region --- Sun: U V radiation --- techniques: spectroscopic

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

    SciTech Connect

    Greene, Jenny E.; Hood, Carol E.; Barth, Aaron J.; Bentz, Misty C.; Walsh, Jonelle L.; Bennert, Vardha N.; Treu, Tommaso; Filippenko, Alexei V.; Gates, Elinor; Malkan, Matthew A.; Woo, Jong-Hak

    2010-11-01

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

  8. Seyfert galaxy narrow-line regions. I - Observations of forbidden O III lambda 5007

    NASA Technical Reports Server (NTRS)

    Vrtilek, J. M.; Carleton, N. P.

    1985-01-01

    High-resolution (23 km/s) spectra of the forbidden O III emission line at 500.7 nm from the nuclear regions of 32 Seyfert galaxies and low-redshift QSOs have been obtained at the Smithsonian Institution/University of Arizona Multiple Mirror Telescope. The properties of the data are summarized by a group of measures which efficiently describe the entire line profiles, are stable in the presence of noise, and have easily visualized geometric meaning. The distributions of line profile measures are shown. In particular, typical forbidden O III FWHM values of 200-520 km/s (mean + or - 1 sigma) and a highly significant tendency for the lines to fall off more slowly on the blue than on the red side of the peak have been found, in agreement with previous work. Using galaxian system velocities obtained from absorption-line measurements, the distribution of differences between forbidden O III emission-line velocities and galaxian system velocities has been determined; in disagreement with previous work, this distribution has been found to be consistent with symmetry about zero difference velocity.

  9. High-resolution laboratory measurements of coronal lines in the 198-218 å region

    SciTech Connect

    Beiersdorfer, Peter; Träbert, Elmar; Lepson, Jaan K.; Brickhouse, Nancy S.; Golub, Leon

    2014-06-10

    We present high-resolution laboratory measurements of the emission from various ions of C, N, O, F, Ne, S, Ar, Fe, and Ni in the extreme ultraviolet wavelength band centered around the λ211 Fe XIV channel of the Atmospheric Imaging Assembly on the Solar Dynamics Observatory. While all of the strong iron lines in this region are well known, we note many weaker lines of iron that are not yet identified. The high resolution of our measurements also allows us to resolve several lines in Fe XI, Fe XII, and Fe XIII between 200 and 205 Å, whose identities were in question based on a disagreement between different databases. The spectra of the elements other than iron are much less known, and we find a multitude of lines that are not yet in the databases. For example, the CHIANTI database clearly disagrees with the NIST data listings on several of the argon lines we observe and also it contains only about half of the observed sulfur lines.

  10. An Observational Test of Transition Region Lines as a Pressure Gauge

    NASA Technical Reports Server (NTRS)

    Siegmund, Oswald H. W.

    1999-01-01

    The objective of this research project was to use high resolution spectroscopic observations from the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) instrument on SOHO (Solar and Heliospheric Observatory) to study the structure of the solar transition region. Our main focus in this grant was to study the variation in density and emission across the quiet Sun transition region.

  11. H-T Phase Diagram of Flux Line Lattice Structure in YNi2B2C

    NASA Astrophysics Data System (ADS)

    Sakiyama, N.; Tsukagoshi, H.; Yano, F.; Nagata, T.; Kawano-Furukawa, H.; Yoshizawa, H.; Yethiraj, M.; Takeya, H.; Suzuki, J.

    2006-09-01

    The detailed flux line lattice (FLL) structure in YNi2B2C was investigated using small angle neutron scattering and the complete H-T phase diagram was determined. The FLL in YNi2B2C shows a change of symmetry only in the low magnetic field region between 0.05 to 0.2 T. The observed square lattice is governed by an anisotropic Fermi velocity. Contrary to the theoretical prediction, a square lattice driven by an anisotropic superconducting gap does not appear below 5 T.

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

    NASA Astrophysics Data System (ADS)

    Lei, Maichang; Wang, Jiancheng

    2014-10-01

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

  13. The case for inflow of the broad-line region of active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Gaskell, C. Martin; Goosmann, René W.

    2016-02-01

    The high-ionization lines of the broad-line region (BLR) of thermal active galactic nuclei (AGNs) show blueshifts of a few hundred km/s to several thousand km/sec with respect to the low-ionization lines. This has long been thought to be due to the high-ionization lines of the BLR arising in a wind of which the far side of the outflow is blocked from our view by the accretion disc. Evidence for and against the disc-wind model is discussed. The biggest problem for the model is that velocity-resolved reverberation mapping repeatedly fails to show the expected kinematic signature of outflow of the BLR. The disc-wind model also cannot readily reproduce the red side of the line profiles of high-ionization lines. The rapidly falling density in an outflow makes it difficult to obtain high equivalent widths. We point out a number of major problems with associating the BLR with the outflows producing broad absorption lines. An explanation which avoids all these problems and satisfies the constraints of both the line profiles and velocity-resolved reverberation-mapping is a model in which the blueshifting is due to scattering off material spiraling inwards with an inflow velocity of half the velocity of the blueshifting. We discuss how recent reverberation mapping results are consistent with the scattering-plus-inflow model but do not support a disc-wind model. We propose that the anti-correlation of the apparent redshifting of Hβ with the blueshifting of C iv is a consequence of contamination of the red wings of Hβ by the broad wings of [O iii].

  14. Genome structure of introgressive lines Triticum aestivum/Aegilops sharonensis.

    PubMed

    Antonyuk, M Z; Bodylyova, M V; Ternovskaya, T K

    2009-01-01

    The lines Triticum aestivum/Aegilops sharonensis were explored in regard to the presence of introgressions in the line genomes, their amount and belonging to definite homoeologic group. The results of studying of chromosome associations in M1 of pollen mother celles in the hybrids between the lines with each other and with recurrent common wheat genotype Avrora were compared with the data of the line assessment for the chromosomal biochemical and morphological markers. 26 lines were distinguished between six groups with specific genome rearrangement regard to recurrent genotype. PMID:20458978

  15. An Analysis of Water Line Profiles in Star Formation Regions Observed by SWAS

    NASA Technical Reports Server (NTRS)

    Ashby, Matthew L. N.; Bergin, Edwin A.; Plume, Rene; Carpenter, John M.; Neufeld, David A.; Chin, Gordon; Erickson, Neal R.; Goldsmith, Paul F.; Harwit, Martin; Howe, J. E.

    2000-01-01

    We present spectral line profiles for the 557 GHz 1(sub 1,0) yields 1(sub 0,1) ground-state rotational transition of ortho-H2(16)O for 18 galactic star formation regions observed by SWAS. 2 Water is unambiguously detected in every source. The line profiles exhibit a wide variety of shapes, including single-peaked spectra and self-reversed profiles. We interpret these profiles using a Monte Carlo code to model the radiative transport. The observed variations in the line profiles can be explained by variations in the relative strengths of the bulk flow and small-scale turbulent motions within the clouds. Bulk flow (infall, outflow) must be present in some cloud cores, and in certain cases this bulk flow dominates the turbulent motions.

  16. Embedded star formation in the extended narrow line region of Centaurus A: Extreme mixing observed by MUSE

    NASA Astrophysics Data System (ADS)

    Santoro, F.; Oonk, J. B. R.; Morganti, R.; Oosterloo, T. A.; Tadhunter, C.

    2016-05-01

    We present a detailed study of the complex ionization structure in a small (~250 pc) extended narrow line region (ENLR) cloud near Centaurus A using the Multi Unit Spectroscopic Explorer. This cloud is located in the so-called outer filament of ionized gas (about 15 kpc from the nucleus) where jet-induced star formation has been suggested to occur by different studies. We find that, despite the small size, a mixture of ionization mechanisms is operating, resulting in considerable complexity in the spatial ionization structure. The area includes two H ii regions where star formation is occurring and another location where star formation must have ceased very recently. Interestingly, the extreme Balmer decrement of one of the star forming regions (Hα/Hβobs ~ 6) indicates that it is still heavily embedded in its natal cocoon of gas and dust. At all three locations a continuum counterpart is found with spectra matching those of O/B stars local to Centaurus A. The H ii regions are embedded in a larger gas complex which is photoionized by the radiation of the central active galactic nucleus (AGN), but the O/B stars affect the spatial ionization pattern in the ENLR cloud very locally. In particular, in the surroundings of the youngest star forming region, we can isolate a tight mixing sequence in the diagnostic diagram going from gas with ionization due to a pure stellar continuum to gas only photoionized by the AGN. These results emphasize the complexity and the mixture of processes occurring in star forming regions under the influence of an AGN radiation. This is relevant for our understanding of AGN-induced star formation suggested to occur in a number of objects, including this region of Centaurus A. They also illustrate that these young stars influence the gas over only a limited region.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    We compare broad emission-line profiles and estimate line ratios for all major emission lines between Lyα and Hβ in a sample of six quasars. The sources were chosen with two criteria in mind: the existence of high-quality optical and ultraviolet spectra and the possibility of sampling the spectroscopic diversity in the 4D eigenvector 1 (4DE1) context. In the latter sense, each source occupies a region (bin) in the full width at half-maximum (FWHM)(Hβ) versus Fe IIopt strength plane that is significantly different from the others. High signal-to-noise ratio Hβ emission-line profiles are used as templates for modelling the other lines (Lyα, C IV λ1549, He II λ1640, Al III λ1860, Si III] λ1892 and Mg II λ2800). We can adequately model all broad lines assuming the existence of three components distinguished by blueshifted, unshifted and redshifted centroids [indicated as a blue component (BLUE), broad component (BC) and very broad component (VBC), respectively]. BC (electron density ne˜ 1012 cm-3, ionization parameter U˜ 10-2 and column density Nc≳ 1023 cm-2) is present in almost all type-1 quasars and therefore corresponds most closely to the classical broad-line emitting region (the reverberating component). The bulk of Mg II λ2800 and Fe II emission also arises in this region. The BLUE emission (log ne˜ 10, log U˜-1 and log Nc < 23) arises in less optically thick gas; it is often thought to arise in an accretion disc wind. The least understood component involves the VBC (high ionization and large column density), which is found in no more than half (but almost all radio-loud) type-1 quasars and luminous Seyfert nuclei. It is perhaps the most distinguishing characteristic of quasars with FWHM (Hβ) ≳ 4000 km s-1 that belong to the so-called population B of our 4DE1 space. Population A quasars [FWHM (Hβ) ≲ 4000 km s-1] are dominated by BC emission in Hβ and BLUE component emission in C IV λ1549 and other high ionization lines. 4DE1 appears to

  18. Climate Services for Adaptation Support: Sectors, Regions, and Product Lines (Invited)

    NASA Astrophysics Data System (ADS)

    Owen, T.; Shea, E. E.

    2009-12-01

    Environmental information for decision support must be user-focused, accurate, and actionable. As the deleterious impacts of a non-stationary climate system manifest themselves through loss of civil infrastructure, cultural, and natural resources, NOAA and other science agencies are restructuring their approach to decision support, moving from a climate perspectives-centric model to one that offers more nimble, granular, and timely product lines supporting a breadth of sectoral- and regionally-focused decisions. This talk outlines NOAA’s efforts to this end, including its framing of sectors and regions, its development of emerging product lines, and its reliance on technological advances to better disseminate information. Through its climate services efforts, NOAA’s climate data resources can be leveraged to support sound adaptation decision making for societal infrastructure development and in the stewardship of marine, ocean, coastal, and terrestrial natural resources.

  19. Near-infrared dust and line emission from the central region of Mrk1066: constraints from Gemini NIFS

    NASA Astrophysics Data System (ADS)

    Riffel, Rogemar A.; Storchi-Bergmann, Thaisa; Nagar, Neil M.

    2010-05-01

    β/Brγ line ratio ranges from E(B - V) ~ 0 to 1.7 with the highest values defining a S-shaped structure along PA ~ 135°/315°. The emission-line ratios are Seyfert-like within the ionization cone indicating that the line emission is powered by the central active nucleus in these locations. Low ionization regions are observed away from the ionization cone, and may be powered by the diffuse radiation field which filters through the ionization cone walls. Two regions at 0.5arcsec south-east and at 1arcsec north-west of the nucleus show starburst-like line ratios, co-spatial with an enhancement in the emission of the H lines. We attribute this change to additional emission from star-forming regions. The mass of ionized gas is MHII ~ 1.7 × 107Msolar and that of hot molecular gas is .

  20. Formation of inner structure of a reconnection separatrix region.

    PubMed

    Khotyaintsev, Yu V; Vaivads, A; Retinò, A; André, M; Owen, C J; Nilsson, H

    2006-11-17

    We present multipoint spacecraft observations at the dayside magnetopause of a magnetic reconnection separatrix region. This region separates two plasmas with significantly different temperatures and densities, at a large distance from the X line. We identify which terms in the generalized Ohm's law balance the observed electric field throughout the separatrix region. The electric field inside a thin approximately c/omega pi Hall layer is balanced by the j x B/ne term while other terms dominate elsewhere. On the low density side of the region we observe a density cavity which forms due to the escape of magnetospheric electrons along the newly opened field lines. The perpendicular electric field inside the cavity constitutes a potential jump of several kV. The observed potential jump and field aligned currents can be responsible for strong aurora. PMID:17155688

  1. Formation of Inner Structure of a Reconnection Separatrix Region

    SciTech Connect

    Khotyaintsev, Yu. V.; Vaivads, A.; Retino, A.; Andre, M.; Owen, C. J.; Nilsson, H.

    2006-11-17

    We present multipoint spacecraft observations at the dayside magnetopause of a magnetic reconnection separatrix region. This region separates two plasmas with significantly different temperatures and densities, at a large distance from the X line. We identify which terms in the generalized Ohm's law balance the observed electric field throughout the separatrix region. The electric field inside a thin {approx}c/{omega}{sub pi} Hall layer is balanced by the jxB/ne term while other terms dominate elsewhere. On the low density side of the region we observe a density cavity which forms due to the escape of magnetospheric electrons along the newly opened field lines. The perpendicular electric field inside the cavity constitutes a potential jump of several kV. The observed potential jump and field aligned currents can be responsible for strong aurora.

  2. Line identification and lifetime measurements in the XUV and soft X-ray regions

    NASA Technical Reports Server (NTRS)

    Sellin, I. A.

    1979-01-01

    A summary of the data acquired concerning line identification and lifetime measurements in the xuv and soft X-ray regions for a variety of both resonance transitions and forbidden transitions in ions of astrophysical interest is provided. Particular attention is called to a few papers which appeared in the Astrophysical Journal. These are of special relevance to specific astrophysical data needs. The many experiments completed in areas related to but somewhat outside the confines of the project title are mentioned.

  3. ISO-LWS observations of Herbig Ae/Be stars. I. Fine structure lines

    NASA Astrophysics Data System (ADS)

    Lorenzetti, D.; Tommasi, E.; Giannini, T.; Nisini, B.; Benedettini, M.; Pezzuto, S.; Strafella, F.; Barlow, M.; Clegg, P. E.; Cohen, M.; di Giorgio, A. M.; Liseau, R.; Molinari, S.; Palla, F.; Saraceno, P.; Smith, H. A.; Spinoglio, L.; White, G. J.

    1999-06-01

    We present the results of the first spectrophotometric survey of a sample of eleven Herbig Ae/Be stars (HAEBE) obtained with the Long Wavelength Spectrometer (LWS) on board the Infrared Space Observatory (ISO). The [OI] 63mu m and the [CII] 158mu m lines are observed in all the investigated sources, while the [OI] 145mu m transition, due to its relative faintness, sometimes remains undetected. By comparing line intensity ratios with model predictions, photodissociation, due to the UV photons from the central star, results the dominating excitation mechanism although contributions of C-shocks to the [OI] emission cannot be ruled out. A clear example for the presence of a photodissociation region (PDR) illuminated by an HAEBE is shown by LWS spectroscopic mapping of NGC 7129. Some diagnostic probes of the radiation field and density are provided for the objects in our sample: these substantially agree with the known characteristics of both the star and its circumstellar environment, although the observed ratio [OI]63/[OI]145 tends to be smaller than predicted by PDR models. The most likely explanation for this behaviour is self-absorption at 63mu m by cold atomic oxygen. Fine structure lines of the ionised species [OIII], [NII] were detected whenever the star had a spectral type of B0 or earlier; in particular, around the star CoD-42(deg) 11721, besides a compact HII region, evidence is given for an extended low electron density ionised region. Finally, molecular line emission is associated with stars powering a CO outflow, and clumpy PDR models, better than C-shock models, predict for them relative cooling (CO vs OI and CO vs OH) similar to the observed ones. Based on observations with ISO, an ESA project with instruments funded by ESA Member States and with the participation of ISAS and NASA}

  4. Tracing planet-induced structures in circumstellar disks using molecular lines

    NASA Astrophysics Data System (ADS)

    Ober, F.; Wolf, S.; Uribe, A. L.; Klahr, H. H.

    2015-07-01

    Context. Circumstellar disks are considered to be the birthplace of planets. Specific structures like spiral arms, gaps, and cavities are characteristic indicators of planet-disk interaction. Investigating these structures can provide insights into the growth of protoplanets and the physical properties of the disk. Aims: We investigate the feasibility of using molecular lines to trace planet-induced structures in circumstellar disks. Methods: Based on 3D hydrodynamic simulations of planet-disk interactions obtained with the PLUTO code, we perform self-consistent temperature calculations and produce N-LTE molecular line velocity-channel maps and spectra of these disks using our new N-LTE line radiative transfer code Mol3D. Subsequently, we simulate ALMA observations using the CASA simulator. We consider two nearly face-on inclinations, five disk masses, seven disk radii, and two different typical pre-main-sequence host stars (T Tauri, Herbig Ae) at a distance of 140 pc. We calculate up to 141 individual velocity-channel maps for five molecules/isotopoloques (12C16O, 12C18O, HCO+, HCN, and CS) in a total of 32 rotational transitions to investigate the frequency dependence of the structures indicated above. Results: We find that the majority of protoplanetary disks in our parameter space could be detected in the molecular lines considered. However, unlike the continuum case, gap detection is not straightforward in lines. For example, gaps are not seen in symmetric rings but are masked by the pattern caused by the global (Keplerian) velocity field. By comparison with simulated observations of undisturbed disks we identify specific regions in the velocity-channel maps that are characteristic of planet-induced structures. Conclusions: Simulations of high angular resolution molecular line observations demonstrate the potential of ALMA to provide complementary information about the planet-disk interaction as compared to continuum observations. In particular, the detection

  5. View facing northeast (60°) of Structure 259, other transmission lines ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View facing northeast (60°) of Structure 25-9, other transmission lines and small farmstead visible in background - Havre Rainbow Transmission Line, Havre City to Great Falls vicinity, Montana, Great Falls, Cascade County, MT

  6. Laboratory Calibration of Density-Dependent Lines in the EUV and Soft X-Ray Regions

    SciTech Connect

    Lepson, J K; Beiersdorfer, P; Gu, M F; Desai, P

    2010-12-09

    We analyzed spectral data of Fe XXII and Ar XIV from laboratory sources in which the electron density varies by several orders of magnitude to help benchmark density-sensitive emission lines useful for astrophysics and to test the atomic models underlying the diagnostic line ratios. We found excellent agreement for Fe XXII, but poorer agreement for Ar XIV. A number of astrophysically important emission lines are sensitive to electron density in the EUV and soft X-ray regions. Lines from Fe XXII, for example, have been used in recent years as diagnostics of stellar coronae, such as the active variable AB Dor, Capella, and EX Hya (Sanz-Forcada et al. 2003, Mewe et al. 2001, Mauche et al. 2003). Here we report spectral data of Fe XXII and Ar XIV from laboratory sources in which the electron density is known from either K-shell density diagnostics (for electron beam ion traps) or from non-spectroscopic means (tokamaks), ranging from 5 x 10{sup 10} cm{sup -3} to 5 x 10{sup 14} cm{sup -3}. These measurements were used to test the atomic data underlying the density diagnostic line ratios, complementing earlier work (Chen et al. 2004).

  7. Reverberation Mapping of the Broad-line Region in NGC 5548: Evidence for Radiation Pressure?

    NASA Astrophysics Data System (ADS)

    Lu, Kai-Xing; Du, Pu; Hu, Chen; Li, Yan-Rong; Zhang, Zhi-Xiang; Wang, Kai; Huang, Ying-Ke; Bi, Shao-Lan; Bai, Jin-Ming; Ho, Luis C.; Wang, Jian-Min

    2016-08-01

    NGC 5548 is the best-observed reverberation-mapped active galactic nucleus with long-term, intensive monitoring. Here we report results from a new observational campaign between 2015 January and July. We measure the centroid time lag of the broad Hβ emission line with respect to the 5100 Å continuum and obtain {τ }{{cent}}={7.20}-0.35+1.33 days in the rest frame. This yields a black hole mass of {M}\\bullet ={8.71}-2.61+3.21× {10}7{M}ȯ using a broad Hβ line dispersion of 3124 ± 302 km s‑1 and a virial factor of {f}{{{BLR}}}=6.3+/- 1.5 for the broad-line region (BLR), consistent with the mass measurements from previous Hβ campaigns. The high-quality data allow us to construct a velocity-binned delay map for the broad Hβ line, which shows a symmetric response pattern around the line center, a plausible kinematic signature of virialized motion of the BLR. Combining all the available measurements of Hβ time lags and the associated mean 5100 Å luminosities over 18 campaigns between 1989 and 2015, we find that the Hβ BLR size varies with the mean optical luminosity, but, interestingly, with a possible delay of {2.35}-1.25+3.47 years. This delay coincides with the typical BLR dynamical timescale of NGC 5548, indicating that the BLR undergoes dynamical changes, possibly driven by radiation pressure.

  8. The lick AGN monitoring project 2011: Fe II reverberation from the outer broad-line region

    SciTech Connect

    Barth, Aaron J.; Cooper, Michael C.; Pancoast, Anna; Treu, Tommaso; Bennert, Vardha N.; Brewer, Brendon J.; Canalizo, Gabriela; Filippenko, Alexei V.; Li, Weidong; Cenko, S. Bradley; Clubb, Kelsey I.; Gates, Elinor L.; Greene, Jenny E.; Malkan, Matthew A.; Sand, David J.; Stern, Daniel; Assef, Roberto J.; Woo, Jong-Hak; Bae, Hyun-Jin; Buehler, Tabitha; and others

    2013-06-01

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

  9. Deconstructing the narrow-line region of the nearest obscured quasar

    NASA Astrophysics Data System (ADS)

    Villar Martín, M.; Bellocchi, E.; Stern, J.; Ramos Almeida, C.; Tadhunter, C.; González Delgado, R.

    2015-11-01

    We study the physical and kinematic properties of the narrow-line region (NLR) of the nearest obscured quasar MRK 477 (z = 0.037), using optical and near-infrared (NIR) spectroscopy. About 100 emission lines are identified in the optical+NIR spectrum (90 in the optical), including several narrow optical Fe+ lines. To our knowledge, this is the first type 2 active galactic nucleus (AGN) with such a detection. The Fe+ lines can be explained as the natural emission from the NLR photoionized by the AGN. Coronal line emission can only be confirmed in the NIR spectrum. As in many other AGNs, a significant correlation is found between the lines' full width at half-maximum and the critical density log(ncrit). We propose that it is caused by the outflow. This could be the case in other AGNs. The nuclear jet-induced ionized outflow has been kinematically isolated in many emission lines covering a broad range of ionization potentials and critical densities. It is concentrated within R ˜few×100 pc from the central engine. The outflowing gas is denser (n ≳ 8000 cm-3) than the ambient non-perturbed gas (n ˜ 400-630 cm-3). This could be due to the compression effect of the jet-induced shocks. Alternatively, we propose that the outflow has been triggered by the jet at R ≲ 220 pc (possibly at ≲ 30 pc), and we trace how the impact weakens as it propagates outwards following the radiation-pressure-dominated density gradient. The different kinematic behaviour of [Fe II] λ1.644 μm suggests that its emission is enhanced by shocks induced by the nuclear outflow/jet and is preferentially emitted at a different, less reddened spatial location.

  10. Quasistatic electric field structures and field-aligned currents in the polar cusp region

    NASA Astrophysics Data System (ADS)

    Jacobsen, K. S.; Moen, J. I.; Pedersen, A.

    2010-10-01

    Cluster data have been examined for quasi-stationary electric field structures and field-aligned currents (FACs) in the vicinity of the dayside cusp region. We have related the measurements to the Region 1/Region 2 (R1/R2) current system and the cusp current system. It has been theoretically proposed that the dayside R1 current may be located on open field lines, and experimental evidence has been shown for R1 currents partially on open field lines. We document that R1 currents may flow entirely on open field lines. The electric field structures are found to occur at plasma density gradients in the cusp. They are associated with strong FACs with current directions that are consistent with the cusp currents. This indicates that the electric field structures are closely coupled to the cusp current system. The electric equipotential structures linking the perpendicular electric fields seen at Cluster altitudes to field-aligned electric fields at lower altitudes fall into one of two categories: S shape or U shape. Both types are found at both the equatorward edge of the cusp ion dispersion and at the equatorward edge of injection events within the cusp. Previous studies in the nightside auroral region attributed the S-shaped potential structures to the boundary transition between the low-density polar cap and the high-density plasma sheet, concluding that the shape of the electric potential structure depends on whether the plasma populations on each side of the structure can support intense currents. This explanation is not applicable for the S-shaped structures observed in the dayside cusp region.

  11. Physical properties of emitting plasma near massive black holes: the Broad Line Region

    NASA Astrophysics Data System (ADS)

    Ilić, D.; Mura, G. La; Popović, L. Č.; Shapovalova, A. I.; Ciroi, S.; Chavushyan, V. H.; Rafanelli, P.; Burenkov, A. N.; Marcado, A.

    2007-04-01

    The dominant emission in Active Galactic Nuclei (AGN) spectra comes from the Broad Emission Lines (BEL) which originate in the Broad Line Region (BLR). The BLR can potentially provide a useful probe of the central part of an AGN, and consequently of the characteristics of the massive Black Hole (BH) that is assumed to be in the center of these objects. The understanding of the physics and kinematics of the BLR is crucial because of the following three reasons: (i) kinematics of the BLR is probably determined by the massive BH, with the competing effects of gravity and radiation pressure, (ii) the BLR reprocesses the UV energy emitted by the continuum source, consequently BEL can provide indirect information about the continuum source, (iii) there is indication that the physical and kinematical parameters of the BEL can be connected with the general characteristics of an AGN (e.g. mass of the BH). In order to connect the physical and kinematical parameters of the BLR, in this work we consider the intensities and widths of Balmer lines of a sample of 90 AGN from Sloan Digital Sky Survey (SDSS). Additionally, we consider the variation of the intensities and widths of Balmer lines from the BLR of NGC 5548 observed from 1996 till 2004. We apply the Boltzmann-Plot method (Popovic 2003, Popovic et al. 2006) to the Balmer line intensities and estimated the electron temperature of a typical BLR. Moreover, we discuss the possibility that the BLR is in general composed from two emitting regions: one that is closer to the BH and contributes to the BEL's wings, and another that is further from the central BH and contributes to the BEL's core.

  12. On the observability of optically thin coronal hyperfine structure lines

    SciTech Connect

    Chatzikos, M.; Ferland, G. J.; Williams, R. J. R.; Fabian, A. C.

    2014-06-01

    We present CLOUDY calculations for the intensity of coronal hyperfine lines in various environments. We model indirect collisional and radiative transitions, and quantify the collisionally excited line emissivity in the density-temperature phase space. As an observational aid, we also express the emissivity in units of that in the 0.4-0.7 keV band. For most hyperfine lines, knowledge of the X-ray surface brightness and the plasma temperature is sufficient for rough estimates. We find that the radiation fields of both Perseus A and Virgo A can enhance the populations of highly ionized species within 1 kpc. They can also enhance line emissivity within the cluster core. This could have implications for the interpretation of spectra around bright active galactic nuclei. We find the intensity of the {sup 57}Fe XXIV λ3.068 mm line to be about two orders of magnitude fainter than previously thought, at ∼20 μK. Comparably bright lines may be found in the infrared. Finally, we find the intensity of hyperfine lines in the Extended Orion Nebula to be low, due to the shallow sightline. Observations of coronal hyperfine lines will likely be feasible with the next generation of radio and submillimeter telescopes.

  13. Yield Line Evaluation Methodology for Reinforced Concrete Structures

    Energy Science and Technology Software Center (ESTSC)

    1998-12-30

    Yield line theory is an analytical technique that can be used to determine the ultimate bending capacity of flat reinforced concrete plates subject to distributed and concentrated loadings. Alternately, yield line theory, combined with rotation limits can be used to determine the energy absorption capacity of plates subject to impulsive and impact loadings. Typical components analyzed by yield line theory are basemats, floor and roof slabs subject to vertical loads along with walls subject tomore » out of plane loadings. One limitation of yield line theory is that it is computationally difficult to evaluate some mechanisms. This problem is aggravated by the complex geometry and reinforcing layouts commonly found in practice. The program has the capability to either evaluate a single user defined mechanism or to iterate over a range of mechanisms to determine the minimum ultimate capacity. The program is verified by comparison to a series of yield line mechanisms with known solutions.« less

  14. Yield Line Evaluation Methodology for Reinforced Concrete Structures

    SciTech Connect

    1998-12-30

    Yield line theory is an analytical technique that can be used to determine the ultimate bending capacity of flat reinforced concrete plates subject to distributed and concentrated loadings. Alternately, yield line theory, combined with rotation limits can be used to determine the energy absorption capacity of plates subject to impulsive and impact loadings. Typical components analyzed by yield line theory are basemats, floor and roof slabs subject to vertical loads along with walls subject to out of plane loadings. One limitation of yield line theory is that it is computationally difficult to evaluate some mechanisms. This problem is aggravated by the complex geometry and reinforcing layouts commonly found in practice. The program has the capability to either evaluate a single user defined mechanism or to iterate over a range of mechanisms to determine the minimum ultimate capacity. The program is verified by comparison to a series of yield line mechanisms with known solutions.

  15. Fine structure of the solar transition region - Observations and interpretation

    NASA Technical Reports Server (NTRS)

    Cook, J. W.; Brueckner, G. E.

    1991-01-01

    An evaluation is conducted of recent high spatial resolution observations of the solar transition region and temperature minimum, in the form of UV spectra and spectroheliographs from both sounding rockets and the Spacelab 2 flights of the High Resolution Telescope and Spectrograph (HRTS). Attention is given to the solar atmosphere structure implications of the HRST's observational results. The inclusion of fine structure in conjectures concerning the transition region affects the plausibility of 1D average models of the solar atmosphere, as well as the determination of temperature gradients, possible nonradiative-heating mechanisms, and the comparison of transition region structures with corresponding observations of the photosphere and corona.

  16. Results of Detailed Modeling of the Narrow-Line Region of Seyfert Galaxies

    NASA Technical Reports Server (NTRS)

    Moore, David; Cohen, Ross D.

    1996-01-01

    We present model line profiles of [O II] lambda3727, [Ne III] lambda3869, [O I] lambda5007, [Fe VII] lambda6087, [Fe X] lambda6374, [O I] lambda6300, H(alpha) lambda6563, and [S 2] lambda6731. The profiles presented here illustrate explicitly the pronounced effects that collisional de-excitation, and that spatial variations in both the ionization parameter and cloud column density, have on Narrow-Line Region (NLR) model profiles. The above effects were included only qualitatively in a previous analytical treatment by Moore and Cohen. By making a direct correspondence between these model profiles and the analytical model profiles of Moore and Cohen, and by comparing with the observed profiles presented in a companion paper and also with those presented elsewhere in the literature, we strengthen some of the conclusions of Moore and Cohen. Most notably, we argue for constant ionization parameter, uniformly accelerated outflow of clouds that are individually stratified in ionization, and the interpretation of emission-line width correlations with ionization potential as a column density effect. For comparison with previous observational studies, such as our own in a companion paper, we also calculate profile parameters for some of the models, and we present and discuss the resulting line width correlations with critical density (n(sub cr)) and Ionization Potential (IP). Because the models we favor are those that produce extended profile wings as observed in high spectral resolution studies, the line width correlations of our favoured models are of particular interest. Line width correlations with n(sub cr) and/or IP result only if the width parameter is more sensitive to extended profile wings than is the Full Width at Half-Maximum (FWHM). Correlations between FWHM and n(sub cr) and/or IP result only after convolving the model profiles with a broad instrumental profile that simulates the lower spectral resolution used in early observational studies. The model in

  17. Synthesis of regional crust and upper-mantle structure from seismic and gravity data

    NASA Technical Reports Server (NTRS)

    Alexander, S. S.; Lavin, P. M.

    1979-01-01

    Available seismic and ground based gravity data are combined to infer the three dimensional crust and upper mantle structure in selected regions. This synthesis and interpretation proceeds from large-scale average models suitable for early comparison with high-altitude satellite potential field data to more detailed delineation of structural boundaries and other variations that may be significant in natural resource assessment. Seismic and ground based gravity data are the primary focal point, but other relevant information (e.g. magnetic field, heat flow, Landsat imagery, geodetic leveling, and natural resources maps) is used to constrain the structure inferred and to assist in defining structural domains and boundaries. The seismic data consists of regional refraction lines, limited reflection coverage, surface wave dispersion, teleseismic P and S wave delay times, anelastic absorption, and regional seismicity patterns. The gravity data base consists of available point gravity determinations for the areas considered.

  18. Line Parameters of the PH_3 Pentad in the 4-5 μm Region

    NASA Astrophysics Data System (ADS)

    Devi, V. Malathy; Benner, D. Chris; Kleiner, I.; Sams, R. L.; Blake, T. A.; Brown, Linda R.; Fletcher, L. N.

    2012-06-01

    Line positions, intensities and line shape parameters are reported for four bands of phosphine between 2150 and 2400 cm-1 in order to improve the spectroscopic database for remote sensing of the giant planets. Knowledge of PH_3 in this spectral region is important for Cassini/VIMS exploration of dynamics and chemistry on Saturn, as well as for interpreting the near-IR data from Juno and ESA's proposed Jupiter mission. For this study, five high-resolution (0.0023 cm-1), high signal-to-noise (>2000) spectra of pure PH_3 were recorded at room temperature (298.2 K) with the Bruker IFS 125HR Fourier transform spectrometer at Pacific Northwest National Laboratory. Individual line parameters were retrieved by multispectrum fitting of all five spectra simultaneously. Positions and intensities were measured for over 3100 transitions. The rotational quantum numbers of measured lines go as high as J''=16 and K''=15 in the ν_3 and ν_1 bands; some lines of the weaker bands 2ν_4 and ν_2+ν_4 are also reported. The measured positions and intensities are compared to new theoretical calculations of the pentad. Lorentz self-broadened width and pressure-induced shift coefficients of many transitions were also obtained, along with speed dependence parameters. Line mixing coefficients were determined for several A+A- pairs of transitions for K''=3, 6, and 9. Research described in this paper was performed at the College of William and Mary and the Jet Propulsion Laboratory, California Institute of Technology, under contracts and cooperative agreements with the National Aeronautics and Space Administration. L. Fletcher acknowledges support from a Glasstone Science Fellowship. D. C. Benner, C. P. Rinsland, V. Malathy Devi, M. A. H. Smith and D. A. Atkins, JQSRT 53 (1995) 705-721.

  19. A NEW RADIO RECOMBINATION LINE MASER OBJECT TOWARD THE MonR2 H II REGION

    SciTech Connect

    Jimenez-Serra, I.; Zhang, Q.; Dierickx, M.; Patel, N.; Baez-Rubio, A.; Rivilla, V. M.; Martin-Pintado, J. E-mail: qzhang@cfa.harvard.edu E-mail: npatel@cfa.harvard.edu E-mail: jmartin@cab.inta-csic.es

    2013-02-10

    We report the detection of a new radio recombination line (RRL) maser object toward the IRS2 source in the MonR2 ultracompact H II region. The continuum emission at 1.3 mm and 0.85 mm and the H30{alpha} and H26{alpha} lines were observed with the Submillimeter Array (SMA) at angular resolutions of {approx}0.''5-3''. The SMA observations show that the MonR2-IRS2 source is very compact and remains unresolved at spatial scales {<=}400 AU. Its continuum power spectrum at millimeter wavelengths is almost flat ({alpha} = -0.16, with S{sub {nu}}{proportional_to}{nu}{sup {alpha}}), indicating that this source is dominated by optically thin free-free emission. The H30{alpha} and H26{alpha} RRL emission is also compact and peaks toward the position of the MonR2-IRS2 source. The measured RRL profiles are double peaked with the H26{alpha} line showing a clear asymmetry in its spectrum. Since the derived line-to-continuum flux ratios ({approx}80 and 180 km s{sup -1} for H30{alpha} and H26{alpha}, respectively) exceed the LTE predictions, the RRLs toward MonR2-IRS2 are affected by maser amplification. The amplification factors are, however, smaller than those found toward the emission-line star MWC349A, indicating that MonR2-IRS2 is a weakly amplified maser. Radiative transfer modeling of the RRL emission toward this source shows that the RRL masers arise from a dense and collimated jet embedded in a cylindrical ionized wind, oriented nearly along the direction of the line of sight. High-angular resolution observations at submillimeter wavelengths are needed to unveil weakly amplified RRL masers in very young massive stars.

  20. Ultraviolet imaging telescope and optical emission-line observations of H II regions in M81

    NASA Technical Reports Server (NTRS)

    Hill, Jesse K.; Cheng, K.-P.; Bohlin, Ralph C.; Cornett, Robert H.; Hintzen, P. M. N.; O'Connell, Robert W.; Roberts, Morton S.; Smith, Andrew M.; Smith, Eric P.; Stecher, Theodore P.

    1995-01-01

    Images of the type Sab spiral galaxy M81 were obtained in far-UV and near-UV bands by the Ultraviolet Imaging Telescope (UIT) during the Astro-1 Spacelab mission of 1990 December. Magnitudes in the two UV bands are determined for 52 H II regions from the catalog of Petit, Sivan, & Karachentsev (1988). Fluxes of the H-alpha and H-beta emission lines are determined from CCD images. Extinctions for the brightest H II regions are determined from observed Balmer decrements. Fainter H II regions are assigned the average of published radio-H-alpha extinctions for several bright H II regions. The radiative transfer models of Witt, Thronson, & Capuano (1992) are shown to predict a relationship between Balmer Decrement and H-alpha extinction consistent with observed line and radio fluxes for the brightest 7 H II regions and are used to estimate the UV extinction. Ratios of Lyman continuum with ratios predicted by model spectra computed for initial mass function (IMF) slope equal to -1.0 and stellar masses ranging from 5 to 120 solar mass. Ages and masses are estimated by comparing the H-alpha and far-UV fluxes and their ratio with the models. The total of the estimated stellar masses for the 52 H II regions is 1.4 x 10(exp 5) solar mass. The star-formation rate inferred for M81 from the observed UV and H-alpha fluxes is low for a spiral galaxy at approximately 0.13 solar mass/yr, but consistent with the low star-formation rates obtained by Kennicutt (1983) and Caldwell et al. (1991) for early-type spirals.

  1. FAR-INFRARED FINE-STRUCTURE LINE DIAGNOSTICS OF ULTRALUMINOUS INFRARED GALAXIES

    SciTech Connect

    Farrah, D.; Petty, S. M.; Harris, K.; Lebouteiller, V.; Spoon, H. W. W.; Bernard-Salas, J.; Pearson, C.; Rigopoulou, D.; Smith, H. A.; González-Alfonso, E.; Clements, D. L.; Efstathiou, A.; Cormier, D.; Afonso, J.; Hurley, P.; Borys, C.; Verma, A.; Cooray, A.; Salvatelli, V.

    2013-10-10

    We present Herschel observations of 6 fine-structure lines in 25 ultraluminous infrared galaxies at z < 0.27. The lines, [O III]52 μm, [N III]57 μm, [O I]63 μm, [N II]122 μm, [O I]145 μm, and [C II]158 μm, are mostly single Gaussians with widths <600 km s{sup –1} and luminosities of 10{sup 7}-10{sup 9} L{sub ☉}. There are deficits in the [O I]63/L{sub IR}, [N II]/L{sub IR}, [O I]145/L{sub IR}, and [C II]/L{sub IR} ratios compared to lower luminosity systems. The majority of the line deficits are consistent with dustier H II regions, but part of the [C II] deficit may arise from an additional mechanism, plausibly charged dust grains. This is consistent with some of the [C II] originating from photodissociation regions or the interstellar medium (ISM). We derive relations between far-IR line luminosities and both the IR luminosity and star formation rate. We find that [N II] and both [O I] lines are good tracers of the IR luminosity and star formation rate. In contrast, [C II] is a poor tracer of the IR luminosity and star formation rate, and does not improve as a tracer of either quantity if the [C II] deficit is accounted for. The continuum luminosity densities also correlate with the IR luminosity and star formation rate. We derive ranges for the gas density and ultraviolet radiation intensity of 10{sup 1} < n < 10{sup 2.5} and 10{sup 2.2} < G{sub 0} < 10{sup 3.6}, respectively. These ranges depend on optical type, the importance of star formation, and merger stage. We do not find relationships between far-IR line properties and several other parameters: active galactic nucleus (AGN) activity, merger stage, mid-IR excitation, and SMBH mass. We conclude that these far-IR lines arise from gas heated by starlight, and that they are not strongly influenced by AGN activity.

  2. HIGH-VELOCITY LINE FORMING REGIONS IN THE TYPE Ia SUPERNOVA 2009ig

    SciTech Connect

    Marion, G. H.; Foley, Ryan J.; Challis, Peter; Kirshner, Robert P.; Vinko, Jozsef; Wheeler, J. Craig; Silverman, Jeffrey M.; Hsiao, Eric Y.; Brown, Peter J.; Filippenko, Alexei V.; Garnavich, Peter; Landsman, Wayne B.; Parrent, Jerod T.; Pritchard, Tyler A.; Roming, Peter W. A.; Wang, Xiaofeng

    2013-11-01

    We report measurements and analysis of high-velocity (HVF) (>20,000 km s{sup –1}) and photospheric absorption features in a series of spectra of the Type Ia supernova (SN) 2009ig obtained between –14 days and +13 days with respect to the time of maximum B-band luminosity (B-max). We identify lines of Si II, Si III, S II, Ca II, and Fe II that produce both HVF and photospheric-velocity (PVF) absorption features. SN 2009ig is unusual for the large number of lines with detectable HVF in the spectra, but the light-curve parameters correspond to a slightly overluminous but unexceptional SN Ia (M{sub B} = –19.46 mag and Δm{sub 15}(B) = 0.90 mag). Similarly, the Si II λ6355 velocity at the time of B-max is greater than 'normal' for an SN Ia, but it is not extreme (v{sub Si} = 13,400 km s{sup –1}). The –14 days and –13 days spectra clearly resolve HVF from Si II λ6355 as separate absorptions from a detached line forming region. At these very early phases, detached HVF are prevalent in all lines. From –12 days to –6 days, HVF and PVF are detected simultaneously, and the two line forming regions maintain a constant separation of about 8000 km s{sup –1}. After –6 days all absorption features are PVF. The observations of SN 2009ig provide a complete picture of the transition from HVF to PVF. Most SNe Ia show evidence for HVF from multiple lines in spectra obtained before –10 days, and we compare the spectra of SN 2009ig to observations of other SNe. We show that each of the unusual line profiles for Si II λ6355 found in early-time spectra of SNe Ia correlate to a specific phase in a common development sequence from HVF to PVF.

  3. Evaluating Possible Heating Mechanisms Using the Transition Region Line Profiles of Late-Type Stars

    NASA Technical Reports Server (NTRS)

    Wood, Brian E.; Linsky, Jeffrey L.; Ayres, Thomas R.

    1997-01-01

    Our analysis of high-resolution Goddard High-Resolution Spectrograph (GHRS) spectra of late-type stars shows that the Si IV and C IV lines formed near 10(exp 5) K can be decomposed into the sum of two Gaussians, a broad component and a narrow component. We find that the flux contribution of the broad components is correlated with both the C IV and X-ray surface fluxes. For main-sequence stars, the widths of the narrow components suggest subsonic nonthermal velocities, and there appears to be a tight correlation between these nonthermal velocities and stellar surface gravity [xi(sub nc) varies as g(sup (-.68 +/-.07))]. For evolved stars with lower surface gravities, the nonthermal velocities suggested by the narrow components are at or just above the sound speed. Nonthermal velocities computed from the widths of the broad components are always highly supersonic. We propose that the broad components are diagnostics for microflare heating. Turbulent dissipation and Alfven waves are both viable candidates for the narrow component heating mechanism. A solar analog for the broad components might be the 'explosive events' detected by the High-Resolution Telescope and Spectrograph (HRTS) experiment. The broad component we observe for the Si IV lambda 1394 line of alpha Cen A, a star that is nearly identical to the Sun, has a FWHM of 109 +/- 10 km/s and is blueshifted by 9 +/- 3 km/s relative to the narrow component. Both of these properties are consistent with the properties of the solar explosive events. However, the alpha Cen A broad component accounts for 25% +/- 4% of the total Si IV line flux, while solar explosive events are currently thought to account for no more than 5% of the Sun's total transition region emission. This discrepancy must be resolved before the connection between broad components and explosive events can be positively established. In addition to our analysis of the Si IV and C IV lines of many stars, we also provide a more thorough analysis of all

  4. Hα emission-line stars in molecular clouds. II. The M 42 region

    NASA Astrophysics Data System (ADS)

    Pettersson, Bertil; Armond, Tina; Reipurth, Bo

    2014-10-01

    We present a deep survey of Hα emission-line stars in the M 42 region using wide-field objective prism films. A total of 1699 Hα emission-line stars were identified, of which 1025 were previously unknown, within an area of 5.̊5 × 5.̊5 centred on the Trapezium Cluster. We present Hα strength estimates, positions, and JHKs photometry extracted from 2MASS, and comparisons to previous surveys. The spatial distribution of the bulk of the stars follows the molecular cloud as seen in CO and these stars are likely to belong to the very young population of stars associated with the Orion Nebula Cluster. Additionally, there is a scattered population of Hα emission-line stars distributed all over the region surveyed, which may consist partly of foreground stars associated with the young NGC 1980 cluster, as well as some foreground and background dMe or Be stars. The present catalogue adds a large number of candidate low-mass young stars belonging to the Orion population, selected independently of their infrared excess or X-ray emission. Full Table 2 is only available in electronic form at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/570/A30

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

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

  6. Fine Structure of the R Absorption Lines of Cr3+ in Antiferromagnetic Dysprosium Aluminum Garnet

    NASA Astrophysics Data System (ADS)

    Aoyagi, Kiyoshi; Kajiura, Masako; Sugano, Satoru

    1981-11-01

    The absorption spectrum of a Cr3+ ion in an antiferromagnetic disprosium aluminum garnet with the Néel temperature TN of 2.5 K, is measured in the red region between 1.7 K and 4.2 K. It is shown that the fine structure of the R1 and R2 lines at 1.7 K can be explained by using an effective Hamiltonian for the t2g3 2E excited state of Cr3+ in the surrounding of the ordered Dy3+ spins. The gross feature of the observed temperature dependence of the fine structure is shown to be reproduced by assuming appropriate exchange interactions of Cr3+ with Dy3+.

  7. Effect of a partial coverage of quasar broad-line regions by intervening -bearing clouds

    NASA Astrophysics Data System (ADS)

    Ofengeim, D. D.; Balashev, S. A.; Ivanchik, A. V.; Kaminker, A. D.; Klimenko, V. V.

    2015-09-01

    We consider the effect of a partial coverage of quasar broad-line regions (QSO BLRs) by intervening -bearing clouds when a part of quasar (QSO) radiation passes by a cloud not taking part in absorption-line system formation of the QSO spectrum. That leads to modification of observable absorption line profiles and consequently to a bias in physical parameters derived from standard absorption line analysis. In application to the absorption systems the effect has been revealed in the analysis of absorption system in the spectrum of Q 1232+082 (see Ivanchik et al. in Mon. Not. R. Astron. Soc. 404:1583, 2010, Balashev et al. in Mon. Not. R. Astron. Soc. 418:357, 2011). We estimate a probability of the effect to be detected in QSO spectra. To do this we derive distribution of BLR sizes of high-z QSOs from Sloan Digital Sky Survey (SDSS) Data Release 9 (DR9) catalogue and assume different distributions of cloud sizes. We conclude that the low limit of the probability is about 11 %. The latest researches shows that about a fifth of observed absorption systems can be partially covered. Accounting of the effect may allow to revise significantly physical parameters of interstellar clouds obtained by the spectral analysis.

  8. The Fundamental Plane of the Broad-line Region in Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Du, Pu; Wang, Jian-Min; Hu, Chen; Ho, Luis C.; Li, Yan-Rong; Bai, Jin-Ming

    2016-02-01

    Broad emission lines in active galactic nuclei (AGNs) mainly arise from gas photoionized by continuum radiation from an accretion disk around a central black hole. The shape of the broad-line profile, described by {{ D }}{{H}β }={{FWHM}}/{σ }{{H}β }, the ratio of full width at half maximum to the dispersion of broad Hβ, reflects the dynamics of the broad-line region (BLR) and correlates with the dimensionless accretion rate (\\overset{\\quad \\cdot }{{M}}) or Eddington ratio ({L}{{bol}}/{L}{{Edd}}). At the same time, \\overset{\\quad \\cdot }{{M}} and {L}{{bol}}/{L}{{Edd}} correlate with {{ R }}{{Fe}}, the ratio of optical Fe ii to Hβ line flux emission. Assembling all AGNs with reverberation mapping measurements of broad Hβ, both from the literature and from new observations reported here, we find a strong bivariate correlation of the form {log}(\\overset{\\quad \\cdot }{{M}},{L}{{bol}}/{L}{{Edd}})=α +β {{ D }}{{H}β }+γ {{ R }}{{Fe}}, where α = (2.47, 0.31), β = -(1.59, 0.82), and γ = (1.34, 0.80). We refer to this as the fundamental plane of the BLR. We apply the plane to a sample of z < 0.8 quasars to demonstrate the prevalence of super-Eddington accreting AGNs are quite common at low redshifts.

  9. The size of the narrow-line-emitting region in the Seyfert 1 galaxy NGC 5548 from emission-line variability

    SciTech Connect

    Peterson, B. M.; Denney, K. D.; De Rosa, G.; Grier, C. J.; Pogge, R. W.; Kochanek, C. S.; Bentz, M. C.; Vestergaard, M.; Kilerci-Eser, E.; Dalla Bontà, E.; Ciroi, S.

    2013-12-20

    The narrow [O III] λλ4959, 5007 emission-line fluxes in the spectrum of the well-studied Seyfert 1 galaxy NGC 5548 are shown to vary with time. From this we show that the narrow-line-emitting region has a radius of only 1-3 pc and is denser (n {sub e} ∼ 10{sup 5} cm{sup –3}) than previously supposed. The [O III] line width is consistent with virial motions at this radius given previous determinations of the black hole mass. Since the [O III] emission-line flux is usually assumed to be constant and is therefore used to calibrate spectroscopic monitoring data, the variability has ramifications for the long-term secular variations of continuum and emission-line fluxes, though it has no effect on shorter-term reverberation studies. We present corrected optical continuum and broad Hβ emission-line light curves for the period 1988-2008.

  10. Constraining the geometry, size scale and physical conditions of outflowing broad absorption line regions in quasars

    NASA Astrophysics Data System (ADS)

    Woo, Sui Chi

    Quasars are known for generating luminosities of up to 1047 erg s--1 in volumes of scales smaller than 2 x 10 15 cm. The optical/UV continuum emission is generally believed to arise from a rotating accretion disk (AD) surrounding a supermassive black hole (SMBH) of ˜ 108 M⊙ . Such emission can be calculated by treating the AD as a multi-temperature blackbody. While the continuum emitting region is well defined, the properties, location and kinematics of the broad emission line regions (BELRs) and broad absorption line regions (BALRs) remain unclear. On one hand, the reverberation mapping technique can give constraints on the location of the BELRs, but not the kinematics. On the other hand, the line-of-sight kinematics of the BALRs is directly observable, but their locations are not well constrained, resulting in a large range of inferred distances, from 0.01 pc to tens of kpc. Therefore, I combined observational results to investigate the geometry, size, and physical conditions of the BELRs and BALRs. I verified that the Lyalpha and CIV BELRs are located at a similar distance. Using these findings, I was able to constrain the size of the Lyalpha BELR and place a lower limit on the size of the N V BALR. I built an empirical model with the optical/UV continuum emission from the AD, the BELR from the chromosphere of the AD, and the outflowing BALR. In the continuum region, I found that over 95 percent of the total flux comes from the region at ~ 125rg, where rg is the gravitational radius of the SMBH. For the BELRs, I computed a disk-wind model with relativistic effects to explain the often-observed single-peaked BEL profiles. However, I show that such a model cannot explain the observed blue asymmetries in the high-ionization BELs or their blueshifted peaks relative to low-ionization BELs. Using results on time variability of BALR gas, and assuming the variability is caused by the gas moving perpendicular across the line-of-sight over a time scale of about a year

  11. On the Correlation between Coronal and Lower Transition Region Structures at Arcsecond Scales

    NASA Astrophysics Data System (ADS)

    Vourlidas, A.; Klimchuk, J. A.; Korendyke, C. M.; Tarbell, T. D.; Handy, B. N.

    2001-12-01

    We compare the morphology of active region structures observed in the 171 Å (T~9×105 K) and Lyα (T~2×104 K) lines. The coronal data were obtained by the Transition Region and Coronal Explorer (TRACE) in support of the Very High Angular Resolution Ultraviolet Telescope (VAULT) sounding rocket launch, which acquired subarcsecond resolution images of an active region in the Lyα line, on 1999 May 7. Using a pair of calibrated, nearly simultaneous images, we find that: (i) a very good correlation exists between the Lyα and 171 Å intensities in the TRACE moss regions, (ii) we can identify several identical structures in some (but not all) moss areas, and (iii) the correlations are greatly reduced at the footpoints of the 171 Å large-scale loops. We derive a lower limit for the Lyα emission measure, under the assumption of effectively optically thin emission, and compare it to the 171 Å emission measure. As in previous studies, we find an excess of Lyα material compared to the amount expected for a thermal conduction-dominated corona-chromosphere transition region, even for structures that appear to be identical in the two wavelengths. This result implies that some other mechanism besides classical heat conduction from the corona must contribute to the observed Lyα intensities. The observations do not support the idea of a physically distinct cool loop component within active regions.

  12. Absolute redshifts in the CIV 1548 A line in the transition region of the quiet sun

    NASA Technical Reports Server (NTRS)

    Henze, William; Engvold, Oddbjorn

    1992-01-01

    Observations with the Ultraviolet Spectrometer and Polarimeter instrument on the SMM spacecraft were made at the polar limb and disk center for the accurate determination of Doppler shifts of the CIV 1548 A emission line formed at 10 exp -5 K in the transition region of the quiet sun. Individual data points representing 3 arcsec square pixels yield both redshifts and blueshifts, but the mean values from four different days of observations are toward the red. The mean redshifts are in the range 4-8 km/s and are produced by nearly vertically directed flows; the uncertainty associated with the mean values corresponds to +/- 0.5 km/s. The redshift increases with brightness of the CIV line.

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

    SciTech Connect

    Chelouche, Doron; Daniel, Eliran; Kaspi, Shai E-mail: shai@wise.tau.ac.il

    2012-05-10

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

  14. Effect of the Drag Force on the Orbital Motion of the Broad-line Region Clouds

    NASA Astrophysics Data System (ADS)

    Khajenabi, Fazeleh

    2016-09-01

    We investigate the orbital motion of cold clouds in the broad-line region of active galactic nuclei subject to the gravity of a black hole, a force due to a non-isotropic central source, and a drag force proportional to the velocity square. The intercloud is described using the standard solutions for the advection-dominated accretion flows. The orbit of a cloud decays because of the drag force, but the typical timescale of clouds falling onto the central black hole is shorter compared to the linear drag case. This timescale is calculated when a cloud moves through a static or rotating intercloud. We show that when the drag force is a quadratic function of the velocity, irrespective of the initial conditions and other input parameters, clouds will generally fall onto the central region much faster than the age of whole system, and since cold clouds present in most of the broad-line regions, we suggest that mechanisms for the continuous creation of the clouds must operate in these systems.

  15. On BWR regional oscillations with rotational symmetry line using SIMULATE-3K

    SciTech Connect

    Dokhane, A.; Ferroukhi, H.; Pautz, A.

    2013-07-01

    A new stability analysis methodology is being developed at the Paul Scherrer Institute (PSI) using the best-estimate coupled neutronic/thermal- hydraulics code, SIMULATE-3K (S3K). This methodology has so far been validated against Leibstadt NPP (KKL) stability tests of C10, C13 and C19, which all show global (in-phase) oscillations. However, the methodology has not yet been validated for regional instabilities and to that aim, a special KKL cycle 07 stability test was selected. Indeed, during this test, the core not only showed growing power oscillation amplitudes in an out-of-phase regime but also an oscillating and rotating symmetry line. Thereby, it was selected in order to verify the S3K capability to predict regional instabilities and on that basis, obtain more insights towards understanding the causes for the oscillatory and rotational behaviour of symmetry lines. The results obtained so far are presented in this paper. First, it is found that the S3K results are in good agreement with measurements both qualitatively and quantitatively, although the resonance frequency is slightly over-predicted. Secondly, the excitation of the out-of-phase mode with oscillations as well as rotation of the symmetry line is also well captured i.e. in accordance to the experimental observations. Related to this, an in-depth analysis of LPRM signals indicates that two out-of-phase oscillation modes associated to two azimuthal neutronic modes are simultaneously excited. Furthermore, it is found that a superposition of these two modes will trigger the symmetry line dynamics and that the behaviour will be guided by the dominance ratio between these two modes. More precisely, the oscillatory behaviour is due to the superposition of the two azimuthal modes but with one dominant mode. The rotational behaviour is however due to the superposition of the two modes with comparable strengths. (authors)

  16. The nuclear region of low luminosity flat radio spectrum sources. II. Emission-line spectra

    NASA Astrophysics Data System (ADS)

    Gonçalves, A. C.; Serote Roos, M.

    2004-01-01

    We report on the spectroscopic study of 19 low luminosity Flat Radio Spectrum (LL FRS) sources selected from Marchã's et al. (\\cite{March96}) 200 mJy sample. In the optical, these objects are mainly dominated by the host galaxy starlight. After correcting the data for this effect, we obtain a new set of spectra clearly displaying weak emission lines; such features carry valuable information concerning the excitation mechanisms at work in the nuclear regions of LL FRS sources. We have used a special routine to model the spectra and assess the intensities and velocities of the emission lines; we have analyzed the results in terms of diagnostic diagrams. Our analysis shows that 79% of the studied objects harbour a Low Ionization Nuclear Emission-line Region (or LINER) whose contribution was swamped by the host galaxy starlight. The remaining objects display a higher ionization spectrum, more typical of Seyferts; due to the poor quality of the spectra, it was not possible to identify any possible large Balmer components. The fact that we observe a LINER-type spectrum in LL FRS sources supports the idea that some of these objects could be undergoing an ADAF phase; in addition, such a low ionization emission-line spectrum is in agreement with the black hole mass values and sub-Eddington accretion rates published for some FRS sources. Based on observations collected at the Multiple Mirror Telescope on Mt. Hopkins. Full Fig. 1 is only available in electronic form at http://www.edpsciences.org

  17. Mechanical behavior and shape optimization of lining structure for subsea tunnel excavated in weathered slot

    NASA Astrophysics Data System (ADS)

    Li, Peng-fei; Zhou, Xiao-jun

    2015-12-01

    Subsea tunnel lining structures should be designed to sustain the loads transmitted from surrounding ground and groundwater during excavation. Extremely high pore-water pressure reduces the effective strength of the country rock that surrounds a tunnel, thereby lowering the arching effect and stratum stability of the structure. In this paper, the mechanical behavior and shape optimization of the lining structure for the Xiang'an tunnel excavated in weathered slots are examined. Eight cross sections with different geometric parameters are adopted to study the mechanical behavior and shape optimization of the lining structure. The hyperstatic reaction method is used through finite element analysis software ANSYS. The mechanical behavior of the lining structure is evidently affected by the geometric parameters of crosssectional shape. The minimum safety factor of the lining structure elements is set to be the objective function. The efficient tunnel shape to maximize the minimum safety factor is identified. The minimum safety factor increases significantly after optimization. The optimized cross section significantly improves the mechanical characteristics of the lining structure and effectively reduces its deformation. Force analyses of optimization process and program are conducted parametrically so that the method can be applied to the optimization design of other similar structures. The results obtained from this study enhance our understanding of the mechanical behavior of the lining structure for subsea tunnels. These results are also beneficial to the optimal design of lining structures in general.

  18. Study of NH3 Line Intensities in the THz and Far-IR Region

    NASA Astrophysics Data System (ADS)

    Yu, Shanshan

    Ammonia (NH3) exists in the interstellar medium, late-type stars and giant planets of our solar system. Its temperature and abundance profiles in these environments, which are derived with its line parameters as fixed input , are commonly used to provide constraints on retrieving minor species. Therefore NH3 line parameters are essential for interpreting astrophysical and planetary spectra from Herschel, SOFIA, ALMA and JWST. However, our work under a predecessor grant with the APRA program revealed significant deficiencies in NH3 intensities in the terahertz and FIR region, including some weak Delta(K)=3 forbidden transitions predicted to be 100 times stronger. The Delta(K)=3 transitions are the ones connecting levels with different K values and therefore the only way other than collisions and l-doubled states to excite NH3 to K>0 levels. Their intensities have to be corrected to explain the observed high K excitation, such as the detection of NH3 (J,K) = (1,1), (2,2)&(14,14) and (18,18) transitions toward the galactic center star forming region Sgr B2, and to provide insights into the radiative- transfer vs. collision excitation mechanics of interstellar NH3. This proposal will remedy the serious deficiencies in the current databases involving NH3 line parameters in the terahertz and FIR region. We will target transitions with intensities greater than 10^{-23} cm-1/ (molecule/cm2) at 296 K, which will be among new astrophysical detections made by SOFIA, ALMA and JWST, and are 1000 times weaker than the strongest ground state transitions. We will retrieve new positions and intensities from existing laboratory spectra, use them to evaluate the current databases and ab initio calculations, and repair the line positions and intensities by replacing poorly calculated values with our new measurements. The proposed research will result in (1) a validated linelist containing the positions, intensities and lower state energies for the very important Delta(K)=3 NH3 FIR

  19. Interfacial structure and rearrangement of nonionic surfactants near a receding contact line

    NASA Astrophysics Data System (ADS)

    Luokkala, Barry B.

    Surfactant solutions exhibit a wide variety of wetting and dewetting behaviors on high energy surfaces. These behaviors are driven by surfactant self-assemblies at the moving contact line. To probe these self-assemblies, we have undertaken a study of surfactant structure at the three interfaces near a receding contact line. We immerse a hydrophilic silica surface in aqueous solutions of polyethyleneglycol monododecyl ether (C12En, 1 ≤ n ≤ 8) below the critical micelle concentration. The substrate is withdrawn from solution at a speed, U < Ucrit, the critical velocity for pulling a macroscopic film on the solid surface, so that a receding contact line moves across the surface. We determine the area per molecule adsorbed at the solid-liquid and liquid-vapor interfaces, and the structural details of the monolayer deposited to the solid-vapor interface at the receding contact line. We also describe in detail a new technique which we have developed for objectively interpreting data from x-ray reflectivity measurements, our primary tool for probing structure at the solid-vapor interface. We find that the adsorbed amount at the solid-liquid interface is a small-to-negligible contribution to the monolayer deposited at the solid-vapor interface for all n. The primary source of the deposited surfactant is the self-assembled layer at the liquid-vapor interface. The density of the deposited monolayer is substantially less than the density at the liquid-vapor interface. Conservation of mass demands a dividing streamline in the bulk, along which surfactant from the liquid-vapor interface is returned to solution. We note a transition at n = 6 from reversible to partially irreversible adsorption, suggesting the ethylene oxide (EO) head groups begin to behave like PEO polymer for n ≥ 6. At the liquid-vapor interface the area per molecule increases monotonically with n, suggesting increasing disorder in the head group region. The deposited monolayer at the solid

  20. Keck HIRES Spectroscopy of Extragalactic H II Regions: C and O Abundances from Recombination Lines

    NASA Astrophysics Data System (ADS)

    Esteban, César; Bresolin, Fabio; Peimbert, Manuel; García-Rojas, Jorge; Peimbert, Antonio; Mesa-Delgado, Adal

    2009-07-01

    We present very deep spectrophotometry of 14 bright extragalactic H II regions belonging to spiral, irregular, and blue compact galaxies. The data for 13 objects were taken with the High Resolution Echelle Spectrometer on the Keck I telescope. We have measured C II recombination lines in 10 of the objects and O II recombination lines in eight of them. We have determined electron temperatures from line ratios of several ions, especially those of low ionization potential. We have found a rather tight linear empirical relation between T e([N II]) and T e([O III]). We have found that O II lines give always larger abundances than [O III] lines. Moreover, the difference of both O++ abundance determinations—the so-called abundance discrepancy factor—is very similar in all the objects, with a mean value of 0.26 ± 0.09 dex, independent of the properties of the H II region and of the parent galaxy. Using the observed recombination lines, we have determined the O, C, and C/O radial abundance gradients for three spiral galaxies: M33, M101, and NGC 2403, finding that C abundance gradients are always steeper than those of O, producing negative C/O gradients across the galactic disks. This result is similar to that found in the Milky Way and has important implications for chemical evolution models and the nucleosynthesis of C. Most of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. Part of the observations were made with the 4.2 m William Herschel Telescope (WHT), operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.

  1. The Mechanosensory Lateral Line System Mediates Activation of Socially-Relevant Brain Regions during Territorial Interactions

    PubMed Central

    Butler, Julie M.; Maruska, Karen P.

    2016-01-01

    Animals use multiple senses during social interactions and must integrate this information in the brain to make context-dependent behavioral decisions. For fishes, the largest group of vertebrates, the mechanosensory lateral line system provides crucial hydrodynamic information for survival behaviors, but little is known about its function in social communication. Our previous work using the African cichlid fish, Astatotilapia burtoni, provided the first empirical evidence that fish use their lateral line system to detect water movements from conspecifics for mutual assessment and behavioral choices. It is unknown, however, where this socially-relevant mechanosensory information is processed in the brain to elicit adaptive behavioral responses. To examine for the first time in any fish species which brain regions receive contextual mechanosensory information, we quantified expression of the immediate early gene cfos as a proxy for neural activation in sensory and socially-relevant brain nuclei from lateral line-intact and -ablated fish following territorial interactions. Our in situ hybridization results indicate that in addition to known lateral line processing regions, socially-relevant mechanosensory information is processed in the ATn (ventromedial hypothalamus homolog), Dl (putative hippocampus homolog), and Vs (putative medial extended amygdala homolog). In addition, we identified a functional network within the conserved social decision-making network (SDMN) whose co-activity corresponds with mutual assessment and behavioral choice. Lateral line-intact and –ablated fight winners had different patterns of co-activity of these function networks and group identity could be determined solely by activation patterns, indicating the importance of mechanoreception to co-activity of the SDMN. These data show for the first time that the mechanosensory lateral line system provides relevant information to conserved decision-making centers of the brain during

  2. The Mechanosensory Lateral Line System Mediates Activation of Socially-Relevant Brain Regions during Territorial Interactions.

    PubMed

    Butler, Julie M; Maruska, Karen P

    2016-01-01

    Animals use multiple senses during social interactions and must integrate this information in the brain to make context-dependent behavioral decisions. For fishes, the largest group of vertebrates, the mechanosensory lateral line system provides crucial hydrodynamic information for survival behaviors, but little is known about its function in social communication. Our previous work using the African cichlid fish, Astatotilapia burtoni, provided the first empirical evidence that fish use their lateral line system to detect water movements from conspecifics for mutual assessment and behavioral choices. It is unknown, however, where this socially-relevant mechanosensory information is processed in the brain to elicit adaptive behavioral responses. To examine for the first time in any fish species which brain regions receive contextual mechanosensory information, we quantified expression of the immediate early gene cfos as a proxy for neural activation in sensory and socially-relevant brain nuclei from lateral line-intact and -ablated fish following territorial interactions. Our in situ hybridization results indicate that in addition to known lateral line processing regions, socially-relevant mechanosensory information is processed in the ATn (ventromedial hypothalamus homolog), Dl (putative hippocampus homolog), and Vs (putative medial extended amygdala homolog). In addition, we identified a functional network within the conserved social decision-making network (SDMN) whose co-activity corresponds with mutual assessment and behavioral choice. Lateral line-intact and -ablated fight winners had different patterns of co-activity of these function networks and group identity could be determined solely by activation patterns, indicating the importance of mechanoreception to co-activity of the SDMN. These data show for the first time that the mechanosensory lateral line system provides relevant information to conserved decision-making centers of the brain during territorial

  3. THE GREEN BANK TELESCOPE H II REGION DISCOVERY SURVEY. IV. HELIUM AND CARBON RECOMBINATION LINES

    SciTech Connect

    Wenger, Trey V.; Bania, T. M.; Balser, Dana S.; Anderson, L. D.

    2013-02-10

    The Green Bank Telescope H II Region Discovery Survey (GBT HRDS) found hundreds of previously unknown Galactic regions of massive star formation by detecting hydrogen radio recombination line (RRL) emission from candidate H II region targets. Since the HRDS nebulae lie at large distances from the Sun, they are located in previously unprobed zones of the Galactic disk. Here, we derive the properties of helium and carbon RRL emission from HRDS nebulae. Our target sample is the subset of the HRDS that has visible helium or carbon RRLs. This criterion gives a total of 84 velocity components (14% of the HRDS) with helium emission and 52 (9%) with carbon emission. For our highest quality sources, the average {sup 4}He{sup +}/H{sup +} abundance ratio by number, (y {sup +}), is 0.068 {+-} 0.023(1{sigma}). This is the same ratio as that measured for the sample of previously known Galactic H II regions. Nebulae without detected helium emission give robust y {sup +} upper limits. There are 5 RRL emission components with y {sup +} less than 0.04 and another 12 with upper limits below this value. These H II regions must have either a very low {sup 4}He abundance or contain a significant amount of neutral helium. The HRDS has 20 nebulae with carbon RRL emission but no helium emission at its sensitivity level. There is no correlation between the carbon RRL parameters and the 8 {mu}m mid-infrared morphology of these nebulae.

  4. Far-infrared lines from H II regions: Abundance variations in the galaxy

    NASA Technical Reports Server (NTRS)

    Simpson, Janet P.; Colgan, Sean W. J.; Rubin, Robert H.; Erickson, Edwin F.; Haas, Michael R.

    1995-01-01

    Far-infrared lines of (N III) (57 microns), (O III) (52, 88 microns), (Ne III) (36 microns), and (S III) (19, 33 microns) have been measured in the H II regions G1.13 - 0.11, W31B, G23.95 + 0.15, G25.38 - 0.18, G29.96 - 0.02, W43, W51e, S156, S158, NGC 3576, NGC 3603, and G298.22-0.34. These observations were made with the facility Cryogenic Grating Spectrometer on the Kuiper Airborne Observatory to examine variations in abundances throughout the Galaxy. Previously published observations of G0.095 + 0.012, G333.60 - 0.21, G45.13 + 0.14A, K3-50, and M17 are also discussed. The giant H II region 30 Doradus in the Large Magellanic Cloud (LMC) was observed for comparison. Fluxes for (Ne II) (12.8 microns), (S IV) (10.5 microns), and the radio free-free continuum were collected from the literature for those sources. Electron densities were estimated from FIR line-pair ratios, and ionic abundances were estimated from the FIR line and radio fluxes. The excitation was estimated from the O(2+)/S(2+) ratio. Corrections for unseen ionization stages were calculated with the use of constnat-density H II region models. The validity and range of applicability of such semiempirical ionization correction schemes are discussed. The abundances with respect to hydrogen exhibit gradients with R(sub G) comparable to those previously measured for our Galaxy and for other galaxies. The overall gradients are d (log N/H)/dR = -0.10 +/- 0.02 dex/kpc, d(log Ne/H)/dR = -0.08 +/- 0.02 dex/kpc and d(log S/H)/dR = 0.07 +/- 0.02 dex/kpc. Compared to the Orion Nebula, the intermediate R(sub G) H II regions with 6 is less than R(sub G) is less than 11 kpc have similar or lower S/H and N/O ratios. The N/O ratios in the inner Galaxy are more than twice those observed in the Orion Nebula and intermediate R(sub G) H II regions. In fact, all the abundance ratios are as well or better fitted by a step fit with two levels than by a linear gradient. As has been noted in previous studies, the N/O ratio

  5. Photoionization Models of the H_2 Emission of the Narrow Line Region of AGNs

    NASA Astrophysics Data System (ADS)

    Aleman, I.; Gruenwald, R.

    2011-05-01

    The excitation mechanism of the narrow line region (NLR) of AGNs is still an open question. Excitation by UV radiation from O and B stars, x-rays from the central black hole, shock from supernovae or jets, or a combination of these mechanisms have been suggested. In the present work, we use photoionization models to study the excitation mechanisms of the H_2 infrared emission lines in the NLR. In the literature, analyzes of the H_2 emission have been done assuming that the molecules is present only in neutral regions (photodissociation regions, x-ray-dominated regions, or shocks; Veilleux et al. 1997, Krabbe et al. 2000, Rigopoulou et al. 2002, Rodriguez-Ardila et al. 2004, 2005, and Davies et al. 2005). However, they are not conclusive. In previous work (Aleman & Gruenwald 2004, 2011), we show that the H_2 emission from the ionized region of PNe can be significant for planetary nebulae (PNe) with hot central stars (T⋆ > 150000 K). Such stars produce copious amounts of high energy photons, which create an extended partially ionized region that favors the H_2 survival. The conditions in the NLR are similar to those in PNe with hot central stars, so we can expect that the H_2 emission might also be important. We obtain and analyze a grid of photoionization models for different NRL parameters. We study the resulting H_2 density and emission, as well as, the formation, destruction, excitation, and de-excitation mechanisms. The higher values observed for the H_2 1-0 S(1)/Brγ ratio cannot be reproduced by our models. The calculated ratios are between 10^-8 and 10^-1, while the observational ration can be as high as 10. The calculated ratio is strongly anti-correlated with the ionization parameter (U) and only models with U<10-3 result in ratios inside the observational range. We show that the NLR is an environment more hostile to the H_2 molecule than the ionized region of PNe. Another interesting result of our calculations is that the H_2 formation on grain surfaces

  6. Line strengths of N2O in the 1120-1440/cm region

    NASA Astrophysics Data System (ADS)

    Toth, R. A.

    1984-06-01

    Line strengths of N2O and its isotopic derivatives in the 1120-1440/cm region were measured at low pressure and high resolution (0.0054/cm). The band strength, rotationless dipole moment matrix elements, and F factor coefficients were considered. First-order nondegenerate perturbation theory was employed to derive explicit expressions for the rotationless dipole moment matrix elements and F factor coefficients. This made it possible to obtain general expressions for the F factor. The derived expressions were also applicable to CO2 bands.

  7. Line strengths of N2O in the 1120-1440/cm region

    NASA Technical Reports Server (NTRS)

    Toth, R. A.

    1984-01-01

    Line strengths of N2O and its isotopic derivatives in the 1120-1440/cm region were measured at low pressure and high resolution (0.0054/cm). The band strength, rotationless dipole moment matrix elements, and F factor coefficients were considered. First-order nondegenerate perturbation theory was employed to derive explicit expressions for the rotationless dipole moment matrix elements and F factor coefficients. This made it possible to obtain general expressions for the F factor. The derived expressions were also applicable to CO2 bands.

  8. Integral Field Spectroscopy of the Extended Emission-Line Region of 4C 37.43

    NASA Astrophysics Data System (ADS)

    Fu, Hai; Stockton, Alan

    2007-09-01

    We present Gemini integral field spectroscopy and Keck II long-slit spectroscopy of the extended emission-line region (EELR) around the quasar 4C 37.43. The velocity structure of the ionized gas is complex and cannot be explained globally by a simple dynamical model. The spectra from the clouds are inconsistent with shock or ``shock + precursor'' ionization models, but they are consistent with photoionization by the quasar nucleus. The best-fit photoionization model requires a low-metallicity [12+log(O/H)<~8.7] two-phase medium, consisting of a matter-bounded diffuse component with a unity filling factor (N~1 cm-3, T~15,000 K), in which are embedded small, dense clouds (N~400 cm-3, T~104 K). The high-density clouds are transient and can be regenerated through compressing the diffuse medium by low-speed shocks (VS<~100 km s-1). Our photoionization model gives a total mass for the ionized gas of about 3×1010 Msolar, and the total kinetic energy implied by this mass and the observed velocity field is ~2×1058 erg. The fact that luminous EELRs are confined to steep-spectrum radio-loud QSOs, yet show no morphological correspondence to the radio jets, suggests that the driving force producing the 4C 37.43 EELR was a roughly spherical blast wave initiated by the production of the jet. That such a mechanism seems capable of ejecting a mass comparable to that of the total interstellar medium of the Milky Way suggests that ``quasar-mode'' feedback may indeed be an efficient means of regulating star formation in the early universe. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq

  9. Virilization of the Broad Line Region in Active Galactic Nuclei—connection between shifts and widths of broad emission lines

    NASA Astrophysics Data System (ADS)

    Jonić, S.; Kovačević-Dojčinović, J.; Ilić, D.; Popović, L. Č.

    2016-03-01

    We investigate the virilization of the emission lines {Hβ } and Mg II in the sample of 287 Type 1 Active Galactic Nuclei taken from the Sloan Digital Sky Survey database. We explore the connections between the intrinsic line shifts and full widths at different levels of maximal intensity. We found that: (i) {Hβ} seems to be a good virial estimator of black hole masses, and an intrinsic redshift of {Hβ} is dominantly caused by the gravitational effect, (ii) there is an anti-correlation between the redshift and width of the wings of the Mg II line, (iii) the broad Mg II line can be used as virial estimator only at 50 % of the maximal intensity, while the widths and intrinsic shifts of the line wings cannot be used for this purpose.

  10. A DEEP CHANDRA ACIS STUDY OF NGC 4151. II. THE INNERMOST EMISSION LINE REGION AND STRONG EVIDENCE FOR RADIO JET-NLR CLOUD COLLISION

    SciTech Connect

    Wang Junfeng; Fabbiano, Giuseppina; Elvis, Martin; Risaliti, Guido; Karovska, Margarita; Zezas, Andreas; Mundell, Carole G.

    2011-07-20

    We have studied the X-ray emission within the inner {approx}150 pc radius of NGC 4151 by constructing high spatial resolution emission line images of blended O VII, O VIII, and Ne IX. These maps show extended structures that are spatially correlated with the radio outflow and optical [O III] emission. We find strong evidence for jet-gas cloud interaction, including morphological correspondences with regions of X-ray enhancement, peaks of near-infrared [Fe II] emission, and optical clouds. In these regions, moreover, we find evidence of elevated Ne IX/O VII ratios; the X-ray emission of these regions also exceeds that expected from nuclear photoionization. Spectral fitting reveals the presence of a collisionally ionized component. The thermal energy of the hot gas suggests that {approx}> 0.1% of the estimated jet power is deposited into the host interstellar medium through interaction between the radio jet and the dense medium of the circumnuclear region. We find possible pressure equilibrium between the collisionally ionized hot gas and the photoionized line-emitting cool clouds. We also obtain constraints on the extended iron and silicon fluorescent emission. Both lines are spatially unresolved. The upper limit on the contribution of an extended emission region to the Fe K{alpha} emission is {approx}< 5% of the total, in disagreement with a previous claim that 65% of the Fe K{alpha} emission originates in the extended narrow line region.

  11. Lines

    ERIC Educational Resources Information Center

    Mires, Peter B.

    2006-01-01

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

  12. Analysis of line structure in handwritten documents using the Hough transform

    NASA Astrophysics Data System (ADS)

    Ball, Gregory R.; Kasiviswanathan, Harish; Srihari, Sargur N.; Narayanan, Aswin

    2010-01-01

    In the analysis of handwriting in documents a central task is that of determining line structure of the text, e.g., number of text lines, location of their starting and end-points, line-width, etc. While simple methods can handle ideal images, real world documents have complexities such as overlapping line structure, variable line spacing, line skew, document skew, noisy or degraded images etc. This paper explores the application of the Hough transform method to handwritten documents with the goal of automatically determining global document line structure in a top-down manner which can then be used in conjunction with a bottom-up method such as connected component analysis. The performance is significantly better than other top-down methods, such as the projection profile method. In addition, we evaluate the performance of skew analysis by the Hough transform on handwritten documents.

  13. Verbal Working Memory Performance Correlates with Regional White Matter Structures in the Frontoparietal Regions

    ERIC Educational Resources Information Center

    Takeuchi, Hikaru; Taki, Yasuyuki; Sassa, Yuko; Hashizume, Hiroshi; Sekiguchi, Atsushi; Fukushima, Ai; Kawashima, Ryuta

    2011-01-01

    Working memory is the limited capacity storage system involved in the maintenance and manipulation of information over short periods of time. Previous imaging studies have suggested that the frontoparietal regions are activated during working memory tasks; a putative association between the structure of the frontoparietal regions and working…

  14. Line-Integral Projection Reconstruction (LPR) with Slice Encoding Techniques: Multislice Regional Imaging in NMR Tomography.

    PubMed

    Oh, C H; Park, H W; Cho, Z H

    1984-01-01

    Line-integral projection reconstruction (LPR) in NMR imaging was found to be useful and has several advantages such as the imaging capability of objects having short T2 and compensation of phase fluctuations arising from the system instability. Although single slice LPR is found to be inefficient and poor in signal-to-noise ratio (SNR), the multislice encoded LPR method is of interest since it has a high SNR and also the capability of selected regional volume or multislice imaging. The latter, i.e., regional volume imaging capability, is a unique property of NMR imaging and offers a variety of imaging capabilities such as simultaneous multislice imaging of sagittal, transaxial, or coronal views. In this paper, we have investigated two basic forms of the multislice encoded imaging methods using LPR, i.e., Fourier and Hadamard-like encoding matrices. Applications of the methods to the experimented NMR imaging show good agreement with predicted behavior. PMID:18234626

  15. Rendering Three-Dimensional Solar Coronal Structures of Active Region 8227

    NASA Technical Reports Server (NTRS)

    Gary, G. A.; Alexander, D. A.

    1999-01-01

    Coronal X-ray and EUV synthesized images are constructed of Active Region 8227 (May-June 1996) and are compared with Yohkoh/SXT, SOHO/EIT, and TRACE observations. Using the rendering technique of Gary (1997) and Alexander, Gary, and Thompson (1998), specific geometric and physical models are used to integrated the plasma emission along the line of sight to obtain a rendered image. The specific instrumental profiles are convolved in the integration process as well as specific heating functions. We analyze coronal X-ray and EUV structures by constructing synthesized image and comparison with observations provide test of specific physical models. We investigate how different pressure distributions within the active region loop system affect the emission characteristics and compare the various results with coronal observations. We investigate how the different heating functions in the active region are reflected in the effect of overall structure of the region. Specific heating rates are tested.

  16. Radiative Transfer and Absorbing Structures in the Transition Region

    NASA Astrophysics Data System (ADS)

    Plovanic, Jacob; Kankelborg, C. C.

    2012-05-01

    A fully satisfactory explanation for the anomalous He II 304 Å intensity in the solar transition region has yet to be offered. As an extension of previous work, we use a full radiative transfer code to build a more consistent model of the transition region that allows the He II line to form with low filling factor and low opacity. Our results are constrained by the quiet sun center-to-limb profile of He II 304 Å obtained from the MOSES sounding rocket mission and by AIA full-disk data.

  17. Helium abundance and ionization structure in the Orion nebula: radio recombination lines observations

    NASA Astrophysics Data System (ADS)

    Poppi, S.; Tsivilev, A. P.; Cortiglioni, S.; Palumbo, G. G. C.; Sorochenko, R. L.

    2007-03-01

    Results of the Ori A HII region mapping based on hydrogen (H), helium (He) and carbon (C) Radio Recombination lines (RRL) are presented. Observations were made with the same angular resolution (2') using the 32 m VLBI dish of Medicina (Italy, 22.4 GHz) and the Pushchino RT-22 dish (Russia, 36.5 GHz). The behaviour of the ionized helium abundance, y^+, with distance from the center shows that the He+ zone size is smaller than that of H^+. Such a behaviour is different for the core and for the envelope, as well as for different directions from the center. The helium abundance, N(He)/N(H)=10.0(± 0.8)%, is measured. Derived line radial velocities, their widths and y+ data support the well-known "blister-type" structure of this HII region. LTE electron temperatures (7800-9600 K) are also measured. Appendices (Figs. 15, 16 and Sect. 4.1 "Carbon RRLs") are only available in electronic form at http://www.aanda.org

  18. SEMICONDUCTOR DEVICES: Trench gate IGBT structure with floating P region

    NASA Astrophysics Data System (ADS)

    Mengliang, Qian; Zehong, Li; Bo, Zhang; Zhaoji, Li

    2010-02-01

    A new trench gate IGBT structure with a floating P region is proposed, which introduces a floating P region into the trench accumulation layer controlled IGBT (TAC-IGBT). The new structure maintains a low on-state voltage drop and large forward biased safe operating area (FBSOA) of the TAC-IGBT structure while reduces the leakage current and improves the breakdown voltage. In addition, it enlarges the short circuit safe operating area (SCSOA) of the TAC-IGBT, and is simple in fabrication and design. Simulation results indicate that, for IGBT structures with a breakdown voltage of 1200 V, the leakage current of the new trench gate IGBT structure is one order of magnitude lower than the TAC-IGBT structure and the breakdown voltage is 150 V higher than the TAC-IGBT.

  19. WHY IS NON-THERMAL LINE BROADENING OF SPECTRAL LINES IN THE LOWER TRANSITION REGION OF THE SUN INDEPENDENT OF SPATIAL RESOLUTION?

    SciTech Connect

    De Pontieu, B.; Martinez-Sykora, J.; McIntosh, S.; Peter, H.; Pereira, T. M. D.

    2015-01-20

    Spectral observations of the solar transition region (TR) and corona show broadening of spectral lines beyond what is expected from thermal and instrumental broadening. The remaining non-thermal broadening is significant (5–30 km s{sup −1}) and correlated with intensity. Here we study spectra of the TR Si iv 1403 Å line obtained at high resolution with the Interface Region Imaging Spectrograph (IRIS). We find that the large improvement in spatial resolution (0.″33) of IRIS compared to previous spectrographs (2″) does not resolve the non-thermal line broadening which, in most regions, remains at pre-IRIS levels of about 20 km s{sup −1}. This invariance to spatial resolution indicates that the processes behind the broadening occur along the line-of-sight (LOS) and/or on spatial scales (perpendicular to the LOS) smaller than 250 km. Both effects appear to play a role. Comparison with IRIS chromospheric observations shows that, in regions where the LOS is more parallel to the field, magneto-acoustic shocks driven from below impact the TR and can lead to significant non-thermal line broadening. This scenario is supported by MHD simulations. While these do not show enough non-thermal line broadening, they do reproduce the long-known puzzling correlation between non-thermal line broadening and intensity. This correlation is caused by the shocks, but only if non-equilibrium ionization is taken into account. In regions where the LOS is more perpendicular to the field, the prevalence of small-scale twist is likely to play a significant role in explaining the invariance and correlation with intensity. (letters)

  20. THE EXTENDED NARROW-LINE REGION OF TWO TYPE-I QUASI-STELLAR OBJECTS

    SciTech Connect

    Oh, Semyeong; Woo, Jong-Hak; Bennert, Vardha N.; Jungwiert, Bruno; Leipski, Christian; Albrecht, Marcus E-mail: woo@astro.snu.ac.kr E-mail: bruno@ig.cas.cz E-mail: leipski@mpia-hd.mpg.de

    2013-04-20

    We investigate the narrow-line region (NLR) of two radio-quiet QSOs, PG1012+008 and PG1307+085, using high signal-to-noise spatially resolved long-slit spectra obtained with FORS1 at the Very Large Telescope. Although the emission is dominated by the point-spread function of the nuclear source, we are able to detect extended NLR emission out to several kiloparsec scales in both QSOs by subtracting the scaled central spectrum from outer spectra. In contrast to the nuclear spectrum, which shows a prominent blue wing and a broad line profile of the [O III] line, the extended emission reveals no clear signs of large-scale outflows. Exploiting the wide wavelength range, we determine the radial change of the gas properties in the NLR, i.e., gas temperature, density, and ionization parameter, and compare them with those of Seyfert galaxies and type-II QSOs. The QSOs have higher nuclear temperature and lower electron density than Seyferts, but show no significant difference compared to type-II QSOs, while the ionization parameter decreases with radial distance, similar to the case of Seyfert galaxies, For PG1012+008, we determine the stellar-velocity dispersion of the host galaxy. Combined with the black hole mass, we find that the luminous radio-quiet QSO follows the local M{sub BH}-{sigma}{sub *} relation of active galactic nuclei.

  1. Relationship between interphasic nucleolar organizer regions and growth rate in two neuroblastoma cell lines.

    PubMed Central

    Derenzini, M.; Pession, A.; Farabegoli, F.; Trerè, D.; Badiali, M.; Dehan, P.

    1989-01-01

    The relationship between the quantity of silver-stained interphasic nucleolar organizer regions (NORs) and nuclear synthetic activity, caryotype, and growth rate was studied in two established neuroblastoma cell lines (CHP 212 and HTB 10). Statistical analysis of silver-stained NORs revealed four times as many in CHP 212 cells compared with HTB 10 cells. No difference was observed in the ribosomal RNA synthesis between the two cell lines. The caryotype index was 1.2 for CHP 212 and 1.0 for HTB 10 cells. The number of chromosomes carrying NORs and the quantity of ribosomal genes was found to be the same for the two cell lines. Doubling time of CHP 212 cells was 20 hours compared with 54 hours for HTB 10 cells. In CHP 212 cells bindering of cell duplication by serum deprivation induced a progressive lowering (calculated at 48, 72, and 96 hours) of the quantity of silver-stained interphasic NORs. Recovery of duplication by new serum addition induced, after 24 hours, an increase of the quantity of silver-stained interphasic NORs up to control levels. In the light of available data, these results indicate that the quantity of interphasic NORs is strictly correlated only to the growth rate of the cell. Images Figure 2 Figure 3 Figure 4 PMID:2705511

  2. 76 FR 21847 - Defense Federal Acquisition Regulation Supplement (DFARS), Alternative Line-Item Structure (DFARS...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-19

    ... Acquisition Regulation Supplement (DFARS), Alternative Line-Item Structure (DFARS Case 2010-D017) AGENCY... standard procedure for offerors to propose an alternative line-item structure that reflects the offeror's business practices for selling and billing commercial items and initial provisioning spares for...

  3. 76 FR 58138 - Defense Federal Acquisition Regulation Supplement (DFARS); Alternative Line Item Structure (DFARS...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-20

    ... Register at 76 FR 21847 on April 19, 2011, to add DFARS language that provides offerors the opportunity to... Acquisition Regulation Supplement (DFARS); Alternative Line Item Structure (DFARS Case 2010-D017) AGENCY... standard procedure for offerors to propose an alternative line item structure that reflects the...

  4. High-Sensitivity Broadband Spectral Line Surveys of Star Forming Regions with the CSO

    NASA Astrophysics Data System (ADS)

    Weaver, Susanna L. Widicus; Sumner, Matthew C.; Rice, Frank; Zmuidzinas, Jonas; Blake, Geoffrey A.

    2009-06-01

    Spectral line surveys are powerful tools for astrochemistry because they circumvent the one-line-at-a-time approach that has historically hampered new molecule identification. Until recently, line surveys were typically motivated by the need to characterize the major components of interstellar clouds, i.e. the so-called ``interstellar weeds." Previously reported surveys therefore often do not provide the sensitivity levels required for identification of new molecules with weak spectral signatures. The goal of our recent observations with the Caltech Submillimeter Observatory (CSO) is to shift the focus of spectral line surveys away from the interstellar weeds and toward detection of new interstellar molecules. We have obtained broadband, high-sensitivity spectra toward several star forming regions with the new λ=1 mm receiver at the CSO. When used with the facility AOS's, this receiver affords 4 GHz of DSB spectral coverage for each LO setting. We have employed a stepped frequency-offset approach to allow for full spectral deconvolution. The noise temperature of this receiver is ˜100 K (SSB), resulting in spectral RMS levels that far surpass those reported in similar previous studies. Our initial observations targeted the Orion and Sagittarius B2(N-LMH) hot cores and a collection of Class 0 sources. We have now completed our coverage of these initial targets, and upcoming observing time has been allocated for similar surveys of the hot cores W51 e1/e2 and G34.3+0.2. We have fully deconvolved 28 GHz of spectra on Orion with RMS levels of T_A^*˜20 mK. Our coverage on Sgr was more limited, yielding ˜8 GHz of fully-deconvolved spectra to the same RMS level. In this talk, we will report on the data analysis for the Orion and Sgr observations, discuss our progress on line surveys of other star-forming regions, and discuss the implications of these results in the context of recent hot core astrochemical models.

  5. On-line Education Initiatives to Galvanize Climate Mitigation in the Great Lakes Region

    NASA Astrophysics Data System (ADS)

    Mooney, M. E.; Ackerman, S. A.

    2014-12-01

    The Cooperative Institute for Meteorological Satellite Studies (CIMSS) is supporting two different on-line education initiatives that teach about climate change while emphasizing informed and effective responses. The first is an on-line introductory level course for undergraduate students (http://c3.ssec.wisc.edu/) offered through the University of Wisconsin-Madison Atmospheric and Oceanic Sciences (AOS) department. Along with a lighter carbon footprint and the convenience of web-based access, students interact via Drupal forums, Google hangouts and twitter. Activities include several pedagogical tools with sustainability-related content and a final project requiring a discussion of regionally relevant mitigation responses to achieve low emission scenarios for assigned locations. The other initiative is a MOOC (massive open online course) focusing on the changing weather and climate in the Great Lakes Region. This 4-week course is set to launch February 23 2015. One of the primary goals of this MOOC will be having participants change four habits, one per week. Each behavior change will provide a personal benefit to participating individuals while also helping to mitigate the collective impacts of climate change. This presentation will share strategies and insights from both projects.

  6. Line segment confidence region-based string matching method for map conflation

    NASA Astrophysics Data System (ADS)

    Huh, Yong; Yang, Sungchul; Ga, Chillo; Yu, Kiyun; Shi, Wenzhong

    2013-04-01

    In this paper, a method to detect corresponding point pairs between polygon object pairs with a string matching method based on a confidence region model of a line segment is proposed. The optimal point edit sequence to convert the contour of a target object into that of a reference object was found by the string matching method which minimizes its total error cost, and the corresponding point pairs were derived from the edit sequence. Because a significant amount of apparent positional discrepancies between corresponding objects are caused by spatial uncertainty and their confidence region models of line segments are therefore used in the above matching process, the proposed method obtained a high F-measure for finding matching pairs. We applied this method for built-up area polygon objects in a cadastral map and a topographical map. Regardless of their different mapping and representation rules and spatial uncertainties, the proposed method with a confidence level at 0.95 showed a matching result with an F-measure of 0.894.

  7. An on-line regional overpower surveillance system for Candu reactors

    SciTech Connect

    Wallace, D. J.; Caxaj, V.; Seidu, A. S.; Hartmann, W.; Sur, B.; McDonald, A.

    2006-07-01

    The current methodology for establishing Regional Overpower Protection (ROP) trip set-points for Canada Deuterium Uranium (Candu{sup R} reactors requires an extensive and detailed assessment of the plant based on a distribution of channel and bundle powers (flux shapes) calculated from a range of device configurations (e.g., zone controller levels, adjuster bank movements, mechanical control absorber movements, shut-off rod insertions) and a set of thermalhydraulic plant data (channel flows, reactor inlet-header temperatures, channel differential pressure). An on-line approach would provide an interface to assist operators in routine monitoring, diagnostic and maintenance activities by providing Critical Channel Powers (CCP) and ROP set points from instantaneous flux shapes derived from real-time detector readings and associated thermalhydraulic conditions. This paper describes an Advanced On-Line Regional Overpower Surveillance (AOL-ROS) system currently under development at Atomic Energy of Canada Limited (AECL) for Candu reactors. Development has been based on an assessment using instantaneous operating data for the period February to April 2004 from a Candu 6 reactor located at Point Lepreau, New Brunswick (Canada). (authors)

  8. Analysis of Transition-Region Emission-Line Profiles from Full-Disk Scans of the Sun Using the SUMER Instrument on SOHO

    NASA Astrophysics Data System (ADS)

    Peter, H.

    1999-05-01

    We examine statistical properties of line profiles seen in full-disk observations with the UV spectrograph SUMER on board SOHO. In the SUMER data archive, full-disk data with complete spectral information are available only for wavelength regions including the He I (584 Å), Ne VIII (770 Å), C III (977 Å) and C IV (1548 Å) emission lines. In this paper we will concentrate on C IV and Ne VIII. Collectively these data provide us with the unique opportunity to study the properties of line profiles in the lower and upper solar transition-region beyond what could be achieved with earlier instruments. In particular, these data reveal the center-to-limb behavior of line shifts and line widths for the first time in a statistically meaningful way. For C IV these data show the well-known redshift of the transition-region lines in the quiet Sun and a clear correlation of the Doppler shift and the nonthermal broadening to the intensity as a characteristic of the network structure. This correlation is not found in the coronal holes. No indications for the network can be found in Ne VIII. For Ne VIII we find a center-to-limb variation of the line shift opposite to C IV, which leads to the conclusion that Ne VIII must be blueshifted at disk center. This also shows the need for a remeasurement of the wavelength of Ne VIII in the laboratory. The center-to-limb variation of the line width leads to the conclusion that the nonresolved motions are not isotropic with a preference for the vertical component. Both lines show a clear signal for an outflow in the polar coronal holes. We discuss the implications of these and other observations for models of the transition-region and corona. The line shift behavior of Ne VIII and other lines from the upper transition-region deserves deeper investigation and probably has pivotal importance in our understanding of the solar transition-region. We are pursuing such work.

  9. Genomic heterogeneity and structural variation in soybean near isogenic lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Near-isogenic lines (NILs) are a critical genetic resource for the soybean research community. The ability to identify and characterize the genes driving the phenotypic differences between NILs is limited by the degree to which differential genetic introgressions can be resolved. Furthermore, the ge...

  10. Sensitivity of bandpass filters using recirculating delay-line structures

    NASA Astrophysics Data System (ADS)

    Heyde, Eric C.

    1996-12-01

    Recirculating delay lines have value notably as sensors and optical signal processors. Most useful applications depend on a high-finesse response from a network. A proof that, with given response parameters, more complex systems can produce behavior that is more stable to the effects of nonidealities than a single recirculating loop is presented.