Science.gov

Sample records for absorption line studies

  1. Studying Velocity Turbulence from Doppler-broadened Absorption Lines: Statistics of Optical Depth Fluctuations

    SciTech Connect

    Lazarian, A.; Pogosyan, D.

    2008-10-10

    We continue our work on developing techniques for studying turbulence with spectroscopic data. We show that Doppler-broadened absorption spectral lines, in particular, saturated absorption lines, can be used within the framework of the previously introduced technique termed the velocity coordinate spectrum (VCS). The VCS relates the statistics of fluctuations along the velocity coordinate to the statistics of turbulence; thus, it does not require spatial coverage by sampling directions in the plane of the sky. We consider lines with different degree of absorption and show that for lines of optical depth less than one, our earlier treatment of the VCS developed for spectral emission lines is applicable, if the optical depth is used instead of intensity. This amounts to correlating the logarithms of absorbed intensities. For larger optical depths and saturated absorption lines, we show that only wings of the line are available for the analysis. In terms of the VCS formalism, this results in introducing an additional window, whose size decreases with the increase of the optical depth. As a result, strongly saturated absorption lines only carry the information about the small-scale turbulence. Nevertheless, the contrast of the fluctuations corresponding to the small-scale turbulence increases with the increase of the optical depth, which provides advantages for studying turbulence by combining lines with different optical depths. By combining different absorption lines one can develop a tomography of the turbulence in the interstellar gas in all its complexity.

  2. Simulation studies of multi-line line-of-sight tunable-diode-laser absorption spectroscopy performance in measuring temperature probability distribution function

    NASA Astrophysics Data System (ADS)

    Zhang, Guang-Le; Liu, Jian-Guo; Kan, Rui-Feng; Xu, Zhen-Yu

    2014-12-01

    Line-of-sight tunable-diode-laser absorption spectroscopy (LOS-TDLAS) with multiple absorption lines is introduced for non-uniform temperature measurement. Temperature binning method combined with Gauss—Seidel iteration method is used to measure temperature probability distribution function (PDF) along the line-of-sight (LOS). Through 100 simulated measurements, the variation of measurement accuracy is investigated with the number of absorption lines, the number of temperature bins and the magnitude of temperature non-uniformity. A field model with 2-T temperature distribution and 15 well-selected absorption lines are used for the simulation study. The Gauss—Seidel iteration method is discussed for its reliability. The investigation result about the variation of measurement accuracy with the number of temperature bins is different from the previous research results.

  3. Absorption Line Studies and the Distribution of Neutral Gas in the Local Interstellar Medium

    NASA Technical Reports Server (NTRS)

    Bruhweiler, F. C.

    1984-01-01

    Previous published absorption line studies performed at ultraviolet and visual wavelengths are combined with new ultraviolet data in order to map out the distribution of HI within 150 pc of the Sun. Newly presented data for distances less than 50 pc further support the local cloud model as presented by Bruhweiler (1982). The Sun is embedded, near the edge of a diffuse cloud with total column density 2 x 10 to the 19th power/sq cm. Most observed directions within 50 pc away from the cloud body reveal trace amounts of gas (N)HI) approximately 10 to the 18th power/sq cm presumably arising in the outer skin of the local cloud. At greater distances (50 approximately or d approximately or 150 pc) most directions show significant absorption with N(HI) 10(19)/sq cm. Two directions, one toward the northern galactic pole (NGP), the other toward beta CMa exhibit unusually low HI column densities out to distances of 150 to 200 pc. However, substantial amounts of gas N(HI) 10 to the 19th power/sq cm, are seen toward the NGP at greater distances. The implicatons of these results on astronomy at wavelengths shortward of 912A are discussed.

  4. The HST quasar absorption line key project. 9: An emission-line study of PG 2251+113

    NASA Technical Reports Server (NTRS)

    Espey, Brian R.; Turnshek, David A.; Lee, Lincoln; Bergeron, Jacqueline; Boksenberg, Alec; Hartig, George F.; Jannuzi, Buell T.; Sargent, W. L. W.; Savage, Blair D.; Schneider, Donald P.

    1994-01-01

    We present Hubble Space Telescope (HST) and quasi-simultaneous ground-based observations of the z = 0.3252 QSO PG 2251+113. We find a correlation between line widths and the critical density for de-excitation of the forbidden emission lines observed in this object. We can show that this correlation also applies to the semiforbidden and possibly also the permitted lines which arise in the broad emission-line region. While this result was predicted from statistical studies, it has never previously been shown to hold in detail in any individual object. This relationship between the narrow and broad emission-line regions may help constrain dynamical models of both regions. We examine the implications of this result for a simple radial infall model of the emitting gas developed to explain the origin of narrow-line profiles.

  5. Molecular absorption in transition region spectral lines

    NASA Astrophysics Data System (ADS)

    Schmit, D. J.; Innes, D.; Ayres, T.; Peter, H.; Curdt, W.; Jaeggli, S.

    2014-09-01

    Aims: We present observations from the Interface Region Imaging Spectrograph (IRIS) of absorption features from a multitude of cool atomic and molecular lines within the profiles of Si IV transition region lines. Many of these spectral lines have not previously been detected in solar spectra. Methods: We examined spectra taken from deep exposures of plage on 12 October 2013. We observed unique absorption spectra over a magnetic element which is bright in transition region line emission and the ultraviolet continuum. We compared the absorption spectra with emission spectra that is likely related to fluorescence. Results: The absorption features require a population of sub-5000 K plasma to exist above the transition region. This peculiar stratification is an extreme deviation from the canonical structure of the chromosphere-corona boundary. The cool material is not associated with a filament or discernible coronal rain. This suggests that molecules may form in the upper solar atmosphere on small spatial scales and introduces a new complexity into our understanding of solar thermal structure. It lends credence to previous numerical studies that found evidence for elevated pockets of cool gas in the chromosphere. Movies associated to Figs. 1 and 2 are available in electronic form at http://www.aanda.org

  6. Do Atoms Really "Emit" Absorption Lines?

    ERIC Educational Resources Information Center

    Brecher, Kenneth

    1991-01-01

    Presents three absorption line sources that enhance student understanding of the phenomena associated with the interaction of light with matter and help dispel the misconception that atoms "emit" absorption lines. Sources include neodymium, food coloring and other common household liquids, and fluorescent materials. (MDH)

  7. Quasar Absorption Line Survey - Cycle 4 High

    NASA Astrophysics Data System (ADS)

    Bahcall, John

    1994-01-01

    The Absorption Line Survey of bright quasars provides a homogeneous data base for studying fundamental questions about the origin and evolution of gaseous systems in the universe. The initial results determine at small redshifts the number densities of Ly-ALPHA systems, of metal-lines and extragalactic halos, of Lyman-limit systems, of associated absorption systems, and the shapes and intensities of quasar emission lines and spectral energy distributions. The survey reveals that much of the sky is covered by high or very high velocity metal-line clouds present in the Galactic halo. A larger sample, which includes the requested Cycle 3 observations, is required to answer many important questions. For example, what is the correlation function of Ly-ALPHA systems at small redshifts? What fraction of the metal, the Ly-ALPHA, and the Ly-limit systems are associated with galaxies and what are the characteristic sizes of the outer gaseous regions of different types of galaxies? Do absorbing systems show evidence of the large-scale structure seen with galaxies and clusters of galaxies? The observations requested in Cycle 3 will extend the region of coverage of the Key Project sample from the redshift range of z = 0.0 to 1.0 (Cycles 1& 2) to z = 0.0 to 1.6 (Cycles 1-3). THIS FILE CONTAINS THE HIGH PRIORITY OBSERVATIONS FROM CYCLES 2 and 3 WHICH WERE NOT COMPLETED IN THOSE CYCLES.

  8. Study of the Many Fluorescent Lines and the Absorption Variability in GX 301-2 with XMM-Newton

    NASA Technical Reports Server (NTRS)

    Fuerst, F.; Suchy, S.; Kreykenbohm, I.; Barragan, L.; Wilms, J.; Pottschmidt, K.; Caballero, I.; Kretschmar, P.; Ferrigno, C.; Rothschild, R. E.

    2011-01-01

    We present an in-depth study of the High Mass X-ray Binary (HMXB) GX 301-2 during its pre-periastron flare using data from the XMM-Newton satellite. The energy spectrum shows a power law continuum absorbed by a large equivalent hydrogen column on the order of 10(exp 24)/ sq cm and a prominent Fe K-alpha fluorescent emission line. Besides the Fe K-alpha line, evidence for Fe K-Beta, Ni K-alpha, Ni K-Beta, S K-alpha, Ar K-alpha, Ca K-alpha, and Cr K-alpha fluorescent lines is found. The observed line strengths are consistent with fluorescence in a cold absorber. This is the first time that Cr K-alpha is seen in emission in the X-ray spectrum of a HMXB. In addition to the modulation by the strong pulse period of approx 685 sec the source is highly variable and shows different states of activity. We perform time-resolved as well as pulse-to-pulse resolved spectroscopy to investigate differences between these states of activity. We find that fluorescent line fluxes are strongly variable and generally follow the overall flux. The N-H value is variable by a factor of 2, but not correlated to continuum normalization. We find an interval of low flux in the light curve in which the pulsations cease almost completely, without any indication of an increasing absorption column. We investigate this dip in detail and argue that it is most likely that during the dip the accretion ceased and the afterglow of the fluorescent iron accounted for the main portion of the X-ray flux. A similar dip was found earlier in RXTE data, and we compare our findings to these results.

  9. Studying Absorption Line Feature in the Relativistic Jet Source GRS 1915+105

    NASA Technical Reports Server (NTRS)

    Tavani, Marco

    1998-01-01

    The galactic superluminal source GRS 1915+105 is among the most interesting objects in our Galaxy. It is subject to erratic accretion instabilities with energization of relativistic jets producing X-ray, optical and radio emission. This source was observed by ASCA on Sept. 27, 1994, April 20, 1995, October 23, 1996 and April 25, 1997 as part of a long timescale investigation. We detected strong variability of the source, and in particular the existence of burst/dip structure in October 1996 and April 1997. Clear evidence of transient absorption features at 6.7, 7.0 and 8.0 keV was obtained for the first time in September 1994 and April 1995. Given the phenomenology of plasmoid energization and ejection, these transient spectral features might be produced by material entrained in the radio jets or in other high-velocity outflows. Our contribution to the interpretation is to incorporate these observations into a overall theoretical picture for GRS 1915+105 also taking into account other observations by XTE and BSAX. The emerging picture is complex. The central source is subject to (most likely) super-Eddington instabilities mediated by magnetic field build-up, reconnection and dissipation in the form of blobs that eventually leads to the formation of transient spectral features from the surrounding of the plasmoid emitting region. A comprehensive theoretical investigation is in progress.

  10. Theoretical study of the spectral shift of the absorption line of Rb and Cs in liquid helium

    NASA Astrophysics Data System (ADS)

    Modesto-Costa, Lucas; Mukherjee, Prasanta K.; Canuto, Sylvio

    2015-07-01

    A combined and sequential use of Monte Carlo simulation and time-dependent density functional theory is made to obtain the excitation line shifts and widths of Rb and Cs embedded in liquid 4He. In each case calculations are made on 100 statistically uncorrelated configurations with Rb (Cs) surrounded by nearly 60 He atoms treated explicitly. Different basis sets and functionals are used for obtaining the blue shifts of the absorption lines 5s → 5p of Rb and 6s → 6p of Cs. Estimate of the line broadening is also made and results for both the shift and broadening are obtained in good agreement with experiment.

  11. A study of the H2O absorption line shifts in the visible spectrum region due to air pressure

    NASA Technical Reports Server (NTRS)

    Grossmann, B. E.; Browell, E. V.; Bykov, A. D.; Kapitanov, V. A.; Korotchenko, E. A.

    1990-01-01

    Results of measured and calculated shift coefficients are presented for 170 absorption lines of H2O in five vibrational-rotational bands. The measurements have been carried out using highly sensitive laser spectrometers with a resolution of at least 0.01/cm; the calculations are based on the Anderson-Tsao-Curnutte-Frost method. Good agreement is obtained between the theoretical and experimental values of the shift coefficients of H2O lines due to N2, O2, and air pressure.

  12. Spectrophotometry of six broad absorption line QSOs

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  13. Non-Voigt Lyalpha Absorption Line Profiles.

    PubMed

    Outram; Carswell; Theuns

    2000-02-01

    Recent numerical simulations have lead to a paradigm shift in our understanding of the intergalactic medium and the loss of a physical justification for Voigt profile fitting of the Lyalpha forest. Many individual lines seen in simulated spectra have significant departures from the Voigt profile, yet could be well fitted by a blend of two or more such lines. We discuss the expected effect on the line profiles due to ongoing gravitational structure formation and Hubble expansion. We develop a method to detect departures from Voigt profiles of the absorption lines in a statistical way and apply this method to simulated Lyalpha forest spectra, confirming that the profiles seen do statistically differ from Voigt profiles. PMID:10622758

  14. Quasar Absorption Studies

    NASA Technical Reports Server (NTRS)

    Mushotzky, Richard (Technical Monitor); Elvis, Martin

    2004-01-01

    The aim of the proposal is to investigate the absorption properties of a sample of inter-mediate redshift quasars. The main goals of the project are: Measure the redshift and the column density of the X-ray absorbers; test the correlation between absorption and redshift suggested by ROSAT and ASCA data; constrain the absorber ionization status and metallicity; constrain the absorber dust content and composition through the comparison between the amount of X-ray absorption and optical dust extinction. Unanticipated low energy cut-offs where discovered in ROSAT spectra of quasars and confirmed by ASCA, BeppoSAX and Chandra. In most cases it was not possible to constrain adequately the redshift of the absorber from the X-ray data alone. Two possibilities remain open: a) absorption at the quasar redshift; and b) intervening absorption. The evidences in favour of intrinsic absorption are all indirect. Sensitive XMM observations can discriminate between these different scenarios. If the absorption is at the quasar redshift we can study whether the quasar environment evolves with the Cosmic time.

  15. Prospects for determining the cosmological helium-3 to helium-4 ratio via absorption-line studies of the local interstellar medium

    NASA Technical Reports Server (NTRS)

    Hurwitz, M.; Bowyer, S.

    1985-01-01

    The prospects for determining the interstellar (He-3)/(He-4) ratio via absorption-line studies in the extreme ultraviolet are considered. A high-resolution extreme-ultraviolet spectrometer fed by a 1-meter-class telescope similar to that discussed in the Far Ultraviolet Spectroscopic Explorer Report (1983) is assumed, and it is found that detection of He-3 may be possible with less than three days of observing time. To measure the (He-3)/(He-4) ratio with sufficient precision to determine the number of light neutrino species will require over 50 days of integration time for each object studied.

  16. Properties of quasar broad absorption line outflows

    NASA Astrophysics Data System (ADS)

    Capellupo, Daniel Moshin

    2012-06-01

    Broad absorption lines (BALs) in quasar spectra identify high velocity outflows that likely exist in all quasars and could play a major role in feedback to galaxy evolution. In this dissertation, I use two methods to illuminate important properties of these outflows with the goal of a better understanding of these outflow systems and ultimately of the connection between quasars and their host galaxies. The variability of BALs can help us understand the structure, evolution, and basic physical properties of the outflows. I report here on a BAL monitoring programme of a sample of 24 luminous quasars at redshifts 1.2absorption to try to ascertain the cause(s) of the variability. I find that Si IV BALs are more likely to vary than C IV BALs. When both C IV and Si IV varied, those changes always occurred in the same sense (either getting weaker or stronger). The multi-epoch data, including up to 10 epochs of data per quasar, show that the BAL changes were not generally monotonic across the full ˜5 to ˜8 yr time span of our observations, suggesting that the characteristic time-scale for significant line variations, and (perhaps) for structural changes in the outflows, is less than a few years. The evidence presented here indicates that the cause of variability is likely a complex mixture of changing ionization in the outflowing

  17. A multi-epoch spectroscopic study of the BAL quasar APM 08279+5255. II. Emission- and absorption-line variability time lags

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    Context. The study of high-redshift bright quasars is crucial to gather information about the history of galaxy assembly and evolution. Variability analyses can provide useful data on the physics of quasar processes and their relation with the host galaxy. Aims: In this study, we aim to measure the black hole mass of the bright lensed BAL QSO APM 08279+5255 at z = 3.911 through reverberation mapping, and to update and extend the monitoring of its C IV absorption line variability. Methods: We perform the first reverberation mapping of the Si IV and C IV emission lines for a high-luminosity quasar at high redshift with the use of 138 R-band photometric data and 30 spectra available over 16 years of observations. We also cross-correlate the C IV absorption equivalent width variations with the continuum light curve to estimate the recombination time lags of the various absorbers and infer the physical conditions of the ionised gas. Results: We find a reverberation-mapping time lag of ~900 rest-frame days for both Si IV and C IV emission lines. This is consistent with an extension of the BLR size-to-luminosity relation for active galactic nuclei up to a luminosity of ~1048 erg s-1, and implies a black hole mass of 1010 M⊙. Additionally, we measure a recombination time lag of ~160 days in the rest frame for the C IV narrow absorption system, which implies an electron density of the absorbing gas of ~2.5 × 104 cm-3. Conclusions: The measured black hole mass of APM 08279+5255 indicates that the quasar resides in an under-massive host-galaxy bulge with Mbulge ~ 7.5MBH, and that the lens magnification is lower than ~8. Finally, the inferred electron density of the narrow-line absorber implies a distance of the order of 10 kpc of the absorbing gas from the quasar, placing it within the host galaxy.

  18. Evidence for Photoionization-driven Broad Absorption Line Variability

    NASA Astrophysics Data System (ADS)

    Wang, Tinggui; Yang, Chenwei; Wang, Huiyuan; Ferland, Gary

    2015-12-01

    We present a qualitative analysis of the variability of quasar broad absorption lines using the large multi-epoch spectroscopic data set of the Sloan Digital Sky Survey Data Release 10. We confirm that variations of absorption lines are highly coordinated among different components of the same ion or the same absorption component of different ions for C iv, Si iv, and N v. Furthermore, we show that the equivalent widths (EWs) of the lines decrease or increase statistically when the continuum brightens or dims. This is further supported by the synchronized variations of emission and absorption-line EWs when the well-established intrinsic Baldwin effect for emission lines is taken into account. We find that the emergence of an absorption component is usually accompanied by the dimming of the continuum while the disappearance of an absorption-line component is accompanied by the brightening of the continuum. This suggests that the emergence or disappearance of a C iv absorption component is only the extreme case, when the ionic column density is very sensitive to continuum variations or the continuum variability the amplitude is larger. These results support the idea that absorption-line variability is driven mainly by changes in the gas ionization in response to continuum variations, that the line-absorbing gas is highly ionized, and in some extreme cases, too highly ionized to be detected in UV absorption lines. Due to uncertainties in the spectroscopic flux calibration, we cannot quantify the fraction of quasars with asynchronized continuum and absorption-line variations.

  19. The Hubble Space Telescope quasar absorption line key project. II - Data calibration and absorption-line selection

    NASA Technical Reports Server (NTRS)

    Schneider, Donald P.; Hartig, George F.; Jannuzi, Buell T.; Kirhakos, Sofia; Saxe, David H.; Weymann, Ray J.; Bahcall, John N.; Bergeron, Jacqueline; Boksenberg, Alec; Sargent, W. L. W.

    1993-01-01

    We present the observational and data processing aspects of the Hubble Space Telescope Quasar Absorption Line Key Project. Topics discussed include the observational technique, calibration of the data, software that simulates the data, the automated procedure used to identify and characterize the absorption features, and the determination of the sensitivity limits of the survey.

  20. Quasar absorption lines with a nonzero cosmological constant

    NASA Technical Reports Server (NTRS)

    Turner, Edwin L.; Ikeuchi, Satoru

    1992-01-01

    Quasar absorption lines in flat universes with nonzero cosmological constant Lambda are examined and compared with more conventional zero Lambda universes. Various evolution effects for intergalactic absorbers and the observed number density evolution of each absorption system are examined in order to discriminate between evolution effects and the cosmological models. An interesting interaction between Lambda effects and cosmic absorption phenomena is explored. Equations describing IGM absorption statistics are developed for nonzero Lambda cosmologies, both for unevolving absorber populations and some of the more popular physical models for the IGM and intergalactic clouds which include the effects of the absorber evolution.

  1. Active Galactic Nuclei Probed by QSO Absorption Lines

    NASA Astrophysics Data System (ADS)

    Misawa, Toru

    2007-07-01

    Quasars are the extremely bright nuclei found in about 10% of galaxies. A variety of absorption features (known collectively as quasar absorption lines) are detected in the rest-frame UV spectra of these objects. While absorption lines that have very broad widths originate in gas that is probably physocally related to the quasars, narrow absorption lines (NALs) were thought to arise in galaxies and/or in the intter-alacttic medium between the quasars and us. Using high-resolution spectra of quasars, it is found that a substantial fraction of NALs arise in gas in the immediate vicinity of the quasars. A dramatically variable, moderately-broad absorption line in the spectrum of the quasar HS 1603+3820l is also found. The variability of this line is monitored in a campaign with Subaru telescope. These observational results are compared to models for outflows from the quasars, specifically, models for accretion disk winds and evaporating obscuring tori. It is quite important to determine the mechanism of outflow because of its cosmological implications. The outflow could expel angular momentum from the accretion disk and enable quasars to accrete and shine. In addition, the outflow may also regulate star formation in the early stages of the assembly of the host galaxy and enrich the interstellar and intergalactic medium with metals.

  2. Broad Absorption Line Quasar catalogues with Supervised Neural Networks

    SciTech Connect

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

    2008-12-05

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

  3. Terahertz vibrational absorption spectroscopy using microstrip-line waveguides

    NASA Astrophysics Data System (ADS)

    Byrne, M. B.; Cunningham, J.; Tych, K.; Burnett, A. D.; Stringer, M. R.; Wood, C. D.; Dazhang, L.; Lachab, M.; Linfield, E. H.; Davies, A. G.

    2008-11-01

    We demonstrate that terahertz microstrip-line waveguides can be used to measure absorption spectra of polycrystalline materials with a high frequency resolution (˜2 GHz) and with a spatial resolution that is determined by the microstrip-line dimensions, rather than the free-space wavelength. The evanescent terahertz-bandwidth electric field extending above the microstrip line interacts with, and is modified by, overlaid dielectric samples, thus enabling the characteristic vibrational absorption resonances in the sample to be probed. As an example, the terahertz absorption spectrum of polycrystalline lactose monohydrate was investigated; the lowest lying mode was observed at 534(±2) GHz, in excellent agreement with free-space measurements. This microstrip technique offers both a higher spatial and frequency resolution than free-space terahertz time-domain spectroscopy and requires no contact between the waveguide and sample.

  4. Outflow and hot dust emission in broad absorption line quasars

    SciTech Connect

    Zhang, Shaohua; Zhou, Hongyan; Wang, Huiyuan; Wang, Tinggui; Xing, Feijun; Jiang, Peng; Zhang, Kai E-mail: whywang@mail.ustc.edu.cn

    2014-05-01

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

  5. Further study on a flow injection on-line multiplexed sorption preconcentration coupled with flame atomic absorption spectrometry for trace element determination.

    PubMed

    Li, Yan; Jiang, Yan; Yan, Xiu-Ping

    2004-10-20

    A further study on a newly developed flow injection (FI) on-line multiplexed sorption preconcentration (MSP) using a knotted reactor coupled with flame atomic absorption spectrometry (FAAS) was carried out to demonstrate its applicability and limitation for trace element determination. For this purpose, Cr(VI), Cu(II), Ni(II) and Co(II) were selected as the analytes, and detailed comparison was made between the MSP-FAAS and conventional FI on-line sorption preconcentration FAAS in respect to retention efficiency and linear ranges of absorbance versus sample loading flow rate and total preconcentration time. Introduction of an air-flow for removal of the residual solution in the KR after each sub-injection in the MSP procedure played a decisive role in the improvement of retention efficiency. The linearity of absorbance versus sample loading flow rate or total preconcentration time was extended to a more degree for the metal ions with less stability of their PDC (pyrrolidine dithiocarbamate) complexes than those with more stable PDC complexes. It seems that the MSP procedure behaves advantages beyond the inflection points in the diagrams of absorbance versus total preconcentration time and sample loading flow rate obtained by conventional (a single continuous) preconcentration procedure. With a sample loading flow rate of 6.0mlmin(-1) and a total preconcentration time of 180s, the retention efficiencies were increased from 25, 46, 41 and 63% with a single continuous sorption preconcentration to 44, 78, 65 and 75% with a six sub-injection preconcentration procedure for Cr(VI), Co(II), Ni(II), and Cu(II), respectively. The detection limits were 0.40, 0.33, 0.31 and 0.26mugl(-1) for Cr(VI), Co(II), Ni(II), and Cu(II), respectively. The precision (R.S.D.) for eleven replicate determination of 2mugl(-1) Cr(VI), Co(II) and Ni(II), and 1mugl(-1) Cu(II), was 2.1, 4.1, 2.6 and 1.7%, respectively. PMID:18969669

  6. Variations in the Absorption Lines Associated with SN 1006

    NASA Astrophysics Data System (ADS)

    Fesen, Robert A.

    Analysis of 8th year IUE data for a faint sdOB star situated behind the young and suspected Type I supernova remnant of AD 1006 together with a careful re-analysis of earlier IUE spectra (Wu et al. 1983) confirm the presence of several very strong and definitely non-stellar absorption lines in this star's UV spectrum (Fesen, Wu, Leventhal, and Hamilton 1986). Exceedingly broad and strong absorption features at 2370 and 2600 A agree well with the relative strengths and wavelengths of the Fe II 2343, 2382, and 2599 A resonance lines and indicate an Fe II mass of about 0.1 solar mass. Other strong absorption features at 1282, 1331, and 1420 A are identified as redshifted S II (1259, 1254), O I (1302), and Si IV (1393, 1402) respectively with radial velocities of 5000 to 6700 km s^-1. The UV spectra of this sdOB star has provided us with an exciting and invaluable observational probe of the elemental composition and dynamical properties of a young Type I supernova remnant via the line-of-sight interception of the remnant's outer ejecta knots and expanding central iron core. The elements, ionization, and velocities implied by these absorption lines are in good agreement with both optical spectral features seen in Type I SN as well as detailed model calculations predicting the final explosive nucleosynthesis production and expansion velocities. Importantly however, some absorption line variations are seen between the 1982/83 and 1986 IUE spectra. Indeed, if the 1282, 1331, and 1420 A features are really due to knots of ejecta with dimensions similar to those of other remnants (i.e., 0.01 pc), these features cannot persist or remain unchanged over time scales greater than a few years. In order to understand fully the nature of the remnant's ejecta, we propose to monitor these changes in these absorption features over the next two IUE observing seasons (1987/88 and 1988/89). The exposure times are well known with the data reduction and analysis already established and

  7. SPECTROPOLARIMETRY OF RADIO-SELECTED BROAD ABSORPTION LINE QUASARS

    SciTech Connect

    DiPompeo, M. A.; Brotherton, M. S.; Becker, R. H.; Gregg, M. D.; Tran, H. D.; White, R. L.; Laurent-Muehleisen, S. A.

    2010-07-15

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

  8. CO Emission from Low-Redshift QSO Absorption Line Systems

    NASA Astrophysics Data System (ADS)

    Walker, C. E.; Bechtold, J.; Black, J. H.

    1994-12-01

    By studying the physical conditions in galaxies at different redshifts, we can begin to understand the evolutionary process of starformation from early epochs to the present. Such studies have been performed at optical and centimeter wavelengths for a number of years. Due to advances in receiver and telescope technology at millimeter and submillimeter wavelengths, molecular line studies have recently been performed toward high redshift absorption line systems. Observations of the mm/submm CO lines in these very young galaxies provide a way to investigate abundances of and conditions in potential starforming material. CO provides some of the strongest emission lines associated with star formation in nearby disk galaxies. Here we report the detection of CO in emission toward 4 galaxies at redshifts of 0.02 to 0.40. From these observations we are able to compute the molecular mass of the starforming material. Studies of starformation in galaxies at low to mid-redshift ranges are important, because these systems represent a transitional phase between starformation at early epochs and the present. Our recent detections of CO emission indicate total molecular masses in three of the galaxies to be a few times 10(9) Msun, using the ``standard conversion factor'' for molecular hydrogen column density to integrated CO intensity ratio (N(H_2)/Ico) and an H_o=75km/s/Mpc and q_o= 0.5. The fourth system, the z=0.40 21 cm absorber toward PKS 1229-021, has a molecular mass of ~ 10(11) M_sunh(-2) . Together with data at other wavelengths, the z=0.40 absorber may be a in pre-starburst phase. All four of our sources were selected to be metal line systems (with high HI column densities) and possess strong FIR fluxes detected by IRAS at 60 and/or 100{microns }. The source possessing the brightest FIR emission among the four is the z=0.05 21 cm absorber toward S4 0248+43. The total observed FIR luminosity for this source is LFIR =3.0x10E11 Lsun. Taking into account its luminosity and

  9. What sodium absorption lines tell us about Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Soker, Noam

    2014-10-01

    We propose that the sodium responsible for the variable Na ID absorption lines in some Type Ia supernovae (SN Ia) originate mainly from dust residing at ˜1 pc from the supernovae. In this Na-from-dust absorption (NaDA) model, the process by which the SN Ia peak luminosity releases sodium from dust at ˜1 pc from the SN is similar to the processes by which solar radiation releases sodium from cometary dust when comets approach a distance of ≲ 1 au from the Sun. The dust grains are not sublimated but rather stay intact, and release sodium by photon-stimulated desorption (or photosputtering). Some of the Na might start in the gas phase before the explosion. Weakening in absorption strength is caused by Na-ionizing radiation of the SN. We apply the NaDA model to SN 2006X and SN 2007le, and find it to comply better with the observed time variability of the Na ID absorption lines than the Na recombination model. The mass in the dusty shell of the NaDA model is much too high to be accounted for in the single-degenerate scenario for SN Ia. Therefore, the presence of variable Na ID lines in some SN Ia further weakens the already very problematic single-degenerate scenario for SN Ia.

  10. A SURVEY OF ALKALI LINE ABSORPTION IN EXOPLANETARY ATMOSPHERES

    SciTech Connect

    Jensen, Adam G.; Redfield, Seth; Endl, Michael; Cochran, William D.; Koesterke, Lars; Barman, Travis S. E-mail: sredfield@wesleyan.edu E-mail: wdc@astro.as.utexas.edu E-mail: barman@lowell.edu

    2011-12-20

    We obtained over 90 hr of spectroscopic observations of four exoplanetary systems with the Hobby-Eberly Telescope. Observations were taken in transit and out of transit, and we analyzed the differenced spectra-i.e., the transmission spectra-to inspect it for absorption at the wavelengths of the neutral sodium (Na I) doublet at {lambda}{lambda}5889, 5895 and neutral potassium (K I) at {lambda}7698. We used the transmission spectrum at Ca I {lambda}6122-which shows strong stellar absorption but is not an alkali metal resonance line that we expect to show significant absorption in these atmospheres-as a control line to examine our measurements for systematic errors. We use an empirical Monte Carlo method to quantify these systematic errors. In a reanalysis of the same data set using a reduction and analysis pipeline that was derived independently, we confirm the previously seen Na I absorption in HD 189733b at a level of (- 5.26 {+-} 1.69) Multiplication-Sign 10{sup -4} (the average value over a 12 A integration band to be consistent with previous authors). Additionally, we tentatively confirm the Na I absorption seen in HD 209458b (independently by multiple authors) at a level of (- 2.63 {+-} 0.81) Multiplication-Sign 10{sup -4}, though the interpretation is less clear. Furthermore, we find Na I absorption of (- 3.16 {+-} 2.06) Multiplication-Sign 10{sup -4} at <3{sigma} in HD 149026b; features apparent in the transmission spectrum are consistent with real absorption and indicate this may be a good target for future observations to confirm. No other results (Na I in HD 147506b and Ca I and K I in all four targets) are significant to {>=}3{sigma}, although we observe some features that we argue are primarily artifacts.

  11. Line by Line Analysis of Carbon Dioxide Absorption for Predicting Global Warming

    NASA Astrophysics Data System (ADS)

    Smith, D. C.

    2010-12-01

    the 12 to 20 micron range is 0.8 W/M2. The increase in the 4 micron band is 0.01 W/M2. (The very strong absorption lines are saturated at CO2 levels of 320 ppm). The total increase in absorbed IR fluence for doubling CO2 is 1.1 W/M2 Detailed calculations of how this absorbed energy heats the earth and what fraction escapes to space must be done for a definitive answer as to what the increase in the Forcing Function is for doubled CO2. Even if all of the absorbed radiation were delivered to the earth, the temperature rise due to doubling CO2 would be 0.26 deg.K. Up to 1/2 the absorbed fluence can be convected/radiated to outer space, which would lead to a temperature rise of 0.13 deg.K. (There is the amplification factor due to increased water vapor that must be added to the direct CO2 contribution but this is also signicantly reduced relative to the 2 deg.K presently accepted). The important difference between the results of this study and the previous predictions, (4W/M2), is probably due to the saturation of the lines which is obscured by band model calculations and is not in the line by line calculations. The conclusion is that man’s contribution to global warming is small.

  12. On Wolf-Rayet stars with unshifted absorption lines

    NASA Astrophysics Data System (ADS)

    Moffat, A. F. J.; Lamontagne, R.; Shara, M. M.; McAlister, H. A.

    1986-06-01

    The authors examine a sample of 16 galactic Wolf-Rayet stars that exhibit unshifted absorption lines, but for which orbital motion involving the WR star and an O-type companion is either unknown or thought to be absent. If all of these are binaries, this would increase the estimate of the binary frequency for WR stars by about 10%. Speckle interferometry of three bright non-WNL+abs stars in Cygnus fails to reveal any astrometric companions down to a separation of 0.05arcsec. Thus, either the absorption lines are intrinsic to the WR star in these three cases or, more likely, they arise in a bound companion. The search for wide spectroscopic orbits for WR 137 and the WN3+abs star WR 3 is re-examined.

  13. Observational Cosmology Using Absorption Lines in Quasar Spectra

    NASA Astrophysics Data System (ADS)

    Aghaee, A.

    2016-09-01

    Distant, highly luminous quasars are important cosmological probes for a variety of astrophysical questions: the first generation of galaxies, the star formation history and metal enrichment in the early Universe, the growth of the first super massive black holes (SMBHs), the role of feedback from quasars and SMBHs in galaxy evolution, the epoch of reionization, etc. In addition, they are used as background illuminating source that reveal any object located by chance on the line of sight. I will present our group works in these issues that can be done using absorption lines in the quasar spectra.

  14. Interstellar absorption lines in the galaxy NGC 1705

    SciTech Connect

    York, D.G.; Caulet, A.; Rybski, P.M.; Gallagher, J.S.; Blades, J.C. Lowell Observatory, Flagstaff, AZ Space Telescope Science Institute, Baltimore, MD )

    1990-03-01

    The possibility is considered, and shown to be plausible, that the strong C IV and Si IV absorption lines in low-resolution ultraviolet spectra of gas-rich dwarf galaxies are primarily interstellar, not stellar as has been supposed. The argument is based on analogies with H II regions in the Local Group, on low-resolution equivalent width measurements of gas-rich dwarf galaxies from the literature and on high-resolution UV spectra of NGC 1705. 48 refs.

  15. Interstellar absorption lines in the galaxy NGC 1705

    NASA Technical Reports Server (NTRS)

    York, Donald G.; Caulet, Adeline; Rybski, Paul M.; Gallagher, John S.; Blades, J. Chris

    1990-01-01

    The possibility is considered, and shown to be plausible, that the strong C IV and Si IV absorption lines in low-resolution ultraviolet spectra of gas-rich dwarf galaxies are primarily interstellar, not stellar as has been supposed. The argument is based on analogies with H II regions in the Local Group, on low-resolution equivalent width measurements of gas-rich dwarf galaxies from the literature and on high-resolution UV spectra of NGC 1705.

  16. Observations of Absorption Lines from Highly Ionized Atoms

    NASA Technical Reports Server (NTRS)

    Jenkins, E. B.

    1984-01-01

    In the ultraviolet spectra of hot stars, absorption lines can be seen from highly ionized species in the interstellar medium. Observations of these features which have been very influential in revising the perception of the medium's various physical states, are discussed. The pervasiveness of O 6 absorption lines, coupled with complementary observations of a diffuse background in soft X-rays and EUV radiation, shows that there is an extensive network of low density gas (n approx. fewX 0.001/cucm) existing at coronal temperatures, 5.3 or = log T or = 6.3. Shocks created by supernova explosions or mass loss from early-type stars can propagate freely through space and eventually transfer a large amount of energy to the medium. To create the coronal temperatures, the shocks must have velocities in excess of 150 km/sec; shocks at somewhat lower velocity 9v or = 100 km/sec) can be directly observed in the lines of Si3. Observations of other lines in the ultraviolet, such as Si 4V and C 5, may highlight the widespread presence of energetic uv radiation from very hot, dward stars. More advanced techniques in visible and X-ray astronomical spectroscopy may open up for inspection selected lines from atoms in much higher stages of ionization.

  17. The Nature of Partial Covering in Broad Absorption Line Quasars

    NASA Astrophysics Data System (ADS)

    Leighly, Karen

    2012-10-01

    Ejected gas is seen as broad absorption lines in 20% of quasars. It has been known for 15 years that prominent lines such as CIV are usually saturated but not black because the absorbing gas only partially covers the continuum emission region. Therefore, column densities estimated from these lines are only lower limits. Accurate column densities can be obtained from rare ions that have two or more transitions from the same lower level, so that the optical depth and covering fraction can be solved for simultanously. Suitable lines are hard to find, so such measurements are rare. We have found that metastable helium is particularly useful for these measurements. Yet despite these advances, partial covering remains a just a parameter and its physical nature is not understood.We propose a unique experiment to constrain the physical nature of partial covering. We will compare the covering fraction measured from PV {a doublet in the far UV} with that measured from metastable HeI {optical and IR}. The ions creating these lines are relatively rare, and they present similar opacity over a wide range of gas parameters. But due to their wide wavelength separation, these lines probe dramatically different regions of the continuum source, the temperature-dependent accretion disk. So we expect different covering fraction behavior for different partial covering scenarios. This experiment is relevant for understanding the geometry and clumpiness of the outflow, and the results may impact our understanding of the global covering fraction, a parameter critical for determining the outflow kinetic luminosity, and thereby estimating feedback efficiency for broad absorption line outflows.

  18. Are cold flows detectable with metal absorption lines?

    NASA Astrophysics Data System (ADS)

    Kimm, Taysun; Slyz, Adrianne; Devriendt, Julien; Pichon, Christophe

    2011-05-01

    Cosmological simulations have shown that dark matter haloes are connected to each other by large-scale filamentary structures. Cold gas flowing within this ‘cosmic web’ is believed to be an important source of fuel for star formation at high redshift. However, the presence of such filamentary gas has never been observationally confirmed despite the fact that its covering fraction within massive haloes at high redshift is predicted to be significant (˜25 per cent). In this Letter, we investigate in detail whether such cold gas is detectable using low-ionization metal absorption lines, such as C IIλ1334, as this technique has a proven observational record for detecting gaseous structures. Using a large statistical sample of galaxies from the MARENOSTRUM N-body+ adaptive mesh refinement (AMR) cosmological simulation, we find that the typical covering fraction of the dense, cold gas in 1012 M⊙ haloes at z˜ 2.5 is lower than expected (˜5 per cent). In addition, the absorption signal by the interstellar medium of the galaxy itself turns out to be so deep and so broad in velocity space that it completely drowns that of the filamentary gas. A detectable signal might be obtained from a cold filament exactly aligned with the line of sight, but this configuration is so unlikely that it would require surveying an overwhelmingly large number of candidate galaxies to tease it out. Finally, the predicted metallicity of the cold gas in filaments is extremely low (≤10-3 Z⊙). If this result persists when higher resolution runs are performed, it would significantly increase the difficulty of detecting filamentary gas inflows using metal lines. However, even if we assume that filaments are enriched to Z⊙, the absorption signal that we compute is still weak. We are therefore led to conclude that it is extremely difficult to observationally prove or disprove the presence of cold filaments as the favourite accretion mode of galaxies using low-ionization metal absorption

  19. Discovery of Broad Soft X-ray Absorption Lines from the Quasar Wind in PDS 456

    NASA Astrophysics Data System (ADS)

    Reeves, J. N.; Braito, V.; Nardini, E.; Behar, E.; O’Brien, P. T.; Tombesi, F.; Turner, T. J.; Costa, M. T.

    2016-06-01

    High-resolution soft X-ray spectroscopy of the prototype accretion disk wind quasar, PDS 456, is presented. Here, the XMM-Newton reflection grating spectrometer spectra are analyzed from the large 2013–2014 XMM-Newton campaign, consisting of five observations of approximately 100 ks in length. During the last observation (OBS. E), the quasar is at a minimum flux level, and broad absorption line (BAL) profiles are revealed in the soft X-ray band, with typical velocity widths of {σ }{{v}}˜ {{10,000}} km s‑1. During a period of higher flux in the third and fourth observations (OBS. C and D, respectively), a very broad absorption trough is also present above 1 keV. From fitting the absorption lines with models of photoionized absorption spectra, the inferred outflow velocities lie in the range ˜ 0.1{--}0.2c. The absorption lines likely originate from He and H-like neon and L-shell iron at these energies. A comparison with earlier archival data of PDS 456 also reveals a similar absorption structure near 1 keV in a 40 ks observation in 2001, and generally the absorption lines appear most apparent when the spectrum is more absorbed overall. The presence of the soft X-ray BALs is also independently confirmed by an analysis of the XMM-Newton EPIC spectra below 2 keV. We suggest that the soft X-ray absorption profiles could be associated with a lower ionization and possibly clumpy phase of the accretion disk wind, where the latter is known to be present in this quasar from its well-studied iron K absorption profile and where the wind velocity reaches a typical value of 0.3c.

  20. VERY LARGE TELESCOPE SPECTROPOLARIMETRY OF BROAD ABSORPTION LINE QSOs

    SciTech Connect

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

    2011-03-15

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

  1. The First HeI* 10830 Broad Absorption Line Quasar

    NASA Astrophysics Data System (ADS)

    Leighly, Karen; Dietrich, M.; Barber, S.

    2010-03-01

    We report discovery of the first metastable HeI* broad absorption line quasar using SpeX on IRTF. The blue-shifted absorption profile extends in velocity space from about -1,000 to -11,000 km/s, and it shows considerable velocity structure of the order of 1,000 km/s. The maximum apparent optical depth is 0.6. Integration over the 10830 apparent optical depth profile yields a lower limit on the log HeI* column density of >14.3. Absorption is also seen in the HeI* λ3888Å line in optical spectra from SDSS and the MDM Hiltner telescope. These two transitions have the same lower level; thus, the covering fraction and optical depth can be determined. A pure partial covering model yields log HeI* column of 15.5-15.7, while a power law absorption distribution yields 16.1. These column densities are significantly larger than the lower limit because of the high ratio of the product of the wavelength and the oscillator strength (23.3). This property, plus the relatively low densities of HeI* in ionized gas, makes HeI* absorption a valuable probe of high column densities. Cloudy simulations were performed to investigate the nature of the absorber. The HeI* column density yielded a lower limit on the log ionization parameter of -0.2 and a corresponding lower limit on the log hydrogen column density of 23. The latter value is at least an order of magnitude larger than those generally obtained from BALQSOs with spectra amenable to partial covering analysis. The lack of Balmer absorption provided an upper limit on the log density of 7. The log kinetic luminosity was constrained to be between 46 and 48, corresponding to at least 0.3% to a large fraction of the bolometric luminosity. A proposed Suzaku observation may remove model degeneracy between the spectral energy distribution and ionization parameter. This work is funded by NSF AST-0707703.

  2. Discovery of carbon radio recombination lines in absorption towards Cygnus A

    NASA Astrophysics Data System (ADS)

    Oonk, J. B. R.; van Weeren, R. J.; Salgado, F.; Morabito, L. K.; Tielens, A. G. G. M.; Rottgering, H. J. A.; Asgekar, A.; White, G. J.; Alexov, A.; Anderson, J.; Avruch, I. M.; Batejat, F.; Beck, R.; Bell, M. E.; van Bemmel, I.; Bentum, M. J.; Bernardi, G.; Best, P.; Bonafede, A.; Breitling, F.; Brentjens, M.; Broderick, J.; Brüggen, M.; Butcher, H. R.; Ciardi, B.; Conway, J. E.; Corstanje, A.; de Gasperin, F.; de Geus, E.; de Vos, M.; Duscha, S.; Eislöffel, J.; Engels, D.; van Enst, J.; Falcke, H.; Fallows, R. A.; Fender, R.; Ferrari, C.; Frieswijk, W.; Garrett, M. A.; Grießmeier, J.; Hamaker, J. P.; Hassall, T. E.; Heald, G.; Hessels, J. W. T.; Hoeft, M.; Horneffer, A.; van der Horst, A.; Iacobelli, M.; Jackson, N. J.; Juette, E.; Karastergiou, A.; Klijn, W.; Kohler, J.; Kondratiev, V. I.; Kramer, M.; Kuniyoshi, M.; Kuper, G.; van Leeuwen, J.; Maat, P.; Macario, G.; Mann, G.; Markoff, S.; McKean, J. P.; Mevius, M.; Miller-Jones, J. C. A.; Mol, J. D.; Mulcahy, D. D.; Munk, H.; Norden, M. J.; Orru, E.; Paas, H.; Pandey-Pommier, M.; Pandey, V. N.; Pizzo, R.; Polatidis, A. G.; Reich, W.; Scaife, A. M. M.; Schoenmakers, A.; Schwarz, D.; Shulevski, A.; Sluman, J.; Smirnov, O.; Sobey, C.; Stappers, B. W.; Steinmetz, M.; Swinbank, J.; Tagger, M.; Tang, Y.; Tasse, C.; Veen, S. ter; Thoudam, S.; Toribio, C.; van Nieuwpoort, R.; Vermeulen, R.; Vocks, C.; Vogt, C.; Wijers, R. A. M. J.; Wise, M. W.; Wucknitz, O.; Yatawatta, S.; Zarka, P.; Zensus, A.

    2014-02-01

    We present the first detection of carbon radio recombination line absorption along the line of sight to Cygnus A. The observations were carried out with the Low Frequency Array in the 33-57 MHz range. These low-frequency radio observations provide us with a new line of sight to study the diffuse, neutral gas in our Galaxy. To our knowledge this is the first time that foreground Milky Way recombination line absorption has been observed against a bright extragalactic background source. By stacking 48 carbon α lines in the observed frequency range we detect carbon absorption with a signal-to-noise ratio of about 5. The average carbon absorption has a peak optical depth of 2 × 10-4, a line width of 10 km s-1 and a velocity of +4 km s-1 with respect to the local standard of rest. The associated gas is found to have an electron temperature Te ˜ 110 K and density ne ˜ 0.06 cm-3. These properties imply that the observed carbon α absorption likely arises in the cold neutral medium of the Orion arm of the Milky Way. Hydrogen and helium lines were not detected to a 3σ peak optical depth limit of 1.5 × 10-4 for a 4 km s-1 channel width. Radio recombination lines associated with Cygnus A itself were also searched for, but are not detected. We set a 3σ upper limit of 1.5 × 10-4 for the peak optical depth of these lines for a 4 km s-1 channel width.

  3. HI Absorption Lines Detected from the Arecibo Legacy Fast ALFA Survey Data

    NASA Astrophysics Data System (ADS)

    Zhong-zu, Wu; Martha P, Haynes; Riccardo, Giovanelli; Ming, Zhu; Ru-rong, Chen

    2015-10-01

    We present some preliminary results of an on-going study of HI 21-cm absorption lines based on the 40% survey data released by the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA). (1) Ten HI candidate absorbers have been detected. Five of them are previously published in the literature, and the rest of them are new detections that need further confirmation. (2) For those sources with no detected absorptions, we have calculated the upper limit of their foreground HI column density NHI. The statistical result of the NHI distribution indicates that the ratio Ts/f between the averaged spin temperature and coverage factor for DLAs (the damped Lyα systems) might be larger than 500 K. The radio frequency interference (RFI) and standing wave are the main factors affecting the detection of HI absorption lines, which have been analyzed and discussed as well in order to find a method of solution. Our study can serve as a pathfinder for the future large-scale search of HI 21-cm absorption lines using the Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST), which is an Arecibo-type radio telescope currently under construction in China with greatly increased sensitivity, bandwidth, and observational sky area. As prospects, we have discussed two types of observational studies of HI absorption lines toward extragalactic sources using the FAST telescope.

  4. Cm and mm Survey of Molecular Absorption Lines in Centaurus A

    NASA Astrophysics Data System (ADS)

    Ott, Juergen; Muller, S.; Meier, D.; Peck, A.; Impellizzeri, V.; Walter, F.; Henkel, C.; Martin, S.; Aalto, S.; van der Werf, P.; Feain, I.; Anderson, C.

    2012-01-01

    We present Australia Telescope Array data of molecular absorption lines toward the bright central core of Centaurus A. The line of sight crosses the prominent dust lane and continues through the disk and eventually through gas that may be very close to the central supermassive black hole. The goal of our the survey is to determine the physical conditions of the gas via analyses of molecular line tracers including molecular abundances and excitation that is sensitive to changes in temperature, density, ionization, and shocks. This study allows us to derive the physical conditions of every absorption line complex and finally let us assign the most likely environments. We present ATCA data in the 20-50GHz range at medium resolution of a few km/s and possibly ALMA data at 3mm and 1mm wavelengths. The project continues with sub-km/s higher spectral resolution for the most important lines in 2012.

  5. Ultraviolet observations of interstellar absorption lines toward SN 1987A

    NASA Technical Reports Server (NTRS)

    Savage, Blair D.; Jenkins, Edward B.; Joseph, Charles L.; De Boer, Klass S.

    1989-01-01

    High-dispersion IUE echelle spectra of SN 1987A were averaged in order to obtain UV absorption-line profiles of the highest possible quality in the direction of SN 1987A. The profiles for Si IV and C IV are quite similar and have much less structure than the Al III profile. On relating column densities, while the C IV and Si IV ratio is relatively constant over the 0-100 km/s velocity range, the C IV to Al III and Si IV to Al III ratios vary by nearly a factor of 10. This suggests that the C IV and Si IV along this sight line in the Galaxy and its halo may have a common origin which differs from that for Al III.

  6. Monitoring the variability of intrinsic absorption lines in quasar spectra , ,

    SciTech Connect

    Misawa, Toru; Charlton, Jane C.; Eracleous, Michael

    2014-09-01

    We have monitored 12 intrinsic narrow absorption lines (NALs) in five quasars and seven mini-broad absorption lines (mini-BALs) in six quasars for a period of 4-12 yr (1-3.5 yr in the quasar rest-frame). We present the observational data and the conclusions that follow immediately from them, as a prelude to a more detailed analysis. We found clear variability in the equivalent widths (EWs) of the mini-BAL systems but no easily discernible changes in their profiles. We did not detect any variability in the NAL systems or in narrow components that are often located at the center of mini-BAL profiles. Variations in mini-BAL EWs are larger at longer time intervals, reminiscent of the trend seen in variable BALs. If we assume that the observed variations result from changes in the ionization state of the mini-BAL gas, we infer lower limits to the gas density ∼10{sup 3}-10{sup 5} cm{sup –3} and upper limits on the distance of the absorbers from the central engine of the order of a few kiloparsecs. Motivated by the observed variability properties, we suggest that mini-BALs can vary because of fluctuations of the ionizing continuum or changes in partial coverage while NALs can vary primarily because of changes in partial coverage.

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

    PubMed

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

    2000-04-20

    We present a deep ASCA observation of a broad absorption line quasar (BALQSO) PG 0946+301. The source was clearly detected in one of the gas imaging spectrometers, but not in any other detector. If BALQSOs have intrinsic X-ray spectra similar to normal radio-quiet quasars, our observations imply that there is Thomson thick X-ray absorption (NH greater, similar1024 cm-2) toward PG 0946+301. This is the largest column density estimated so far toward a BALQSO. The absorber must be at least partially ionized and may be responsible for attenuation in the optical and UV. If the Thomson optical depth toward BALQSOs is close to 1, as inferred here, then spectroscopy in hard X-rays with large telescopes like XMM would be feasible.

  8. Monitoring the Variability of Intrinsic Absorption Lines in Quasar Spectra

    NASA Astrophysics Data System (ADS)

    Misawa, Toru; Charlton, Jane C.; Eracleous, Michael

    2014-09-01

    We have monitored 12 intrinsic narrow absorption lines (NALs) in five quasars and seven mini-broad absorption lines (mini-BALs) in six quasars for a period of 4-12 yr (1-3.5 yr in the quasar rest-frame). We present the observational data and the conclusions that follow immediately from them, as a prelude to a more detailed analysis. We found clear variability in the equivalent widths (EWs) of the mini-BAL systems but no easily discernible changes in their profiles. We did not detect any variability in the NAL systems or in narrow components that are often located at the center of mini-BAL profiles. Variations in mini-BAL EWs are larger at longer time intervals, reminiscent of the trend seen in variable BALs. If we assume that the observed variations result from changes in the ionization state of the mini-BAL gas, we infer lower limits to the gas density ~103-105 cm-3 and upper limits on the distance of the absorbers from the central engine of the order of a few kiloparsecs. Motivated by the observed variability properties, we suggest that mini-BALs can vary because of fluctuations of the ionizing continuum or changes in partial coverage while NALs can vary primarily because of changes in partial coverage. Based on data collected at Subaru telescope, which is operated by the National Astronomical Observatory of Japan. Based on observations obtained at the European Southern Observatory at La Silla, Chile in programs 65.O-0063(B), 65.O-0474(A), 67.A-0078(A), 68.A-0461(A), 69.A-0204(A), 70.B-0522(A), 072.A-0346(A), 076.A-0860(A), 079.B-0469(A), and 166.A-0106(A).

  9. The Physical Nature of Polar Broad Absorption Line Quasars

    NASA Technical Reports Server (NTRS)

    Ghost, Kajal; Punsly, Brian

    2007-01-01

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

  10. Fraunhofer-type absorption lines in double-pulse laser-induced plasma.

    PubMed

    Nagli, Lev; Gaft, Michael; Gornushkin, Igor

    2012-03-01

    We studied the confocal double-pulse laser-induced plasma in the very beginning of its life. It was found that the second laser pulse fired 0.7 to 5 µs after the first pulse produces plasma which, during the first 0 to 20 ns, resembles solar configuration. There is a very hot and compact plasma core that radiates a broad continuum spectrum and a much larger and cooler outer shell. The light from the hot core passes through the cold outer shell and is partly absorbed by atoms and ions that are in ground (or close to ground) states. This produces absorption lines that are similar to Fraunhofer lines observed in the sun spectrum. The possibility to use these absorption lines for new direct and calibration free laser-induced breakdown spectroscopy analytical applications, both in laboratory and industrial conditions, is proved.

  11. The Redshift Dependence of Gamma-Ray Absorption in the Environments of Strong-Line AGNs

    SciTech Connect

    Reimer, A.; /Stanford U., HEPL /KIPAC, Menlo Park

    2007-11-12

    The case of {gamma}-ray absorption due to photon-photon pair production of jet photons in the external photon environments, such as the accretion disk and the broad-line region radiation fields, of {gamma}-ray--loud active galactic nuclei (AGNs) that exhibit strong emission lines is considered. I demonstrate that this 'local opacity,' if detected, will almost unavoidably be redshift-dependent in the sub-TeV range. This introduces nonnegligible biases and complicates approaches for studying the evolution of the extragalactic background light with contemporary GeV instruments such as the Gamma-Ray Large Area Space Telescope (GLAST ), where the {gamma}-ray horizon is probed by means of statistical analysis of absorption features (e.g., the Fazio-Stecker relation) in AGN spectra at various redshifts. It particularly applies to strong-line quasars, where external photon fields are potentially involved in {gamma}-ray production.

  12. UNSHIFTED METASTABLE He I* MINI-BROAD ABSORPTION LINE SYSTEM IN THE NARROW-LINE TYPE 1 QUASAR SDSS J080248.18+551328.9

    SciTech Connect

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

    2015-02-10

    We report the identification of an unusual absorption-line system in the quasar SDSS J080248.18+551328.9 and present a detailed study of the system, incorporating follow-up optical and near-IR spectroscopy. A few tens of absorption lines are detected, including He I*, Fe II*, and Ni II*, which arise from metastable or excited levels, as well as resonant lines in Mg I, Mg II, Fe II, Mn II, and Ca II. All of the isolated absorption lines show the same profile of width Δv ∼ 1500 km s{sup –1} centered at a common redshift as that of the quasar emission lines, such as [O II], [S II], and hydrogen Paschen and Balmer series. With narrow Balmer lines, strong optical Fe II multiplets, and weak [O III] doublets, its emission-line spectrum is typical for that of a narrow-line Seyfert 1 galaxy (NLS1). We have derived reliable measurements of the gas-phase column densities of the absorbing ions/levels. Photoionization modeling indicates that the absorber has a density of n {sub H} ∼ (1.0-2.5) × 10{sup 5} cm{sup –3} and a column density of N {sub H} ∼ (1.0-3.2) × 10{sup 21} cm{sup –2} and is located at R ∼100-250 pc from the central supermassive black hole. The location of the absorber, the symmetric profile of the absorption lines, and the coincidence of the absorption- and emission-line centroid jointly suggest that the absorption gas originates from the host galaxy and is plausibly accelerated by stellar processes, such as stellar winds and/or supernova explosions. The implications for the detection of such a peculiar absorption-line system in an NLS1 are discussed in the context of coevolution between supermassive black hole growth and host galaxy buildup.

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  14. Probing the Inner Regions of Protoplanetary Disks with CO Absorption Line Spectroscopy

    NASA Astrophysics Data System (ADS)

    McJunkin, Matthew; France, Kevin; Burgh, Eric B.; Herczeg, Gregory J.; Schindhelm, Eric; Brown, Joanna M.; Brown, Alexander

    2013-03-01

    Carbon monoxide (CO) is the most commonly used tracer of molecular gas in the inner regions of protoplanetary disks. CO can be used to constrain the excitation and structure of the circumstellar environment. Absorption line spectroscopy provides an accurate assessment of a single line of sight through the protoplanetary disk system, giving more straightforward estimates of column densities and temperatures than CO and molecular hydrogen (H2) emission line studies. We analyze new observations of ultraviolet CO absorption from the Hubble Space Telescope along the sightlines to six classical T Tauri stars. Gas velocities consistent with the stellar velocities, combined with the moderate-to-high disk inclinations, argue against the absorbing CO gas originating in a fast-moving disk wind. We conclude that the far-ultraviolet observations provide a direct measure of the disk atmosphere or possibly a slow disk wind. The CO absorption lines are reproduced by model spectra with column densities in the range N(12CO) ~ 1016-1018 cm-2 and N(13CO) ~ 1015-1017 cm-2, rotational temperatures T rot(CO) ~ 300-700 K, and Doppler b-values, b ~ 0.5-1.5 km s-1. We use these results to constrain the line-of-sight density of the warm molecular gas (n CO ~ 70-4000 cm-3) and put these observations in context with protoplanetary disk models.

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

    SciTech Connect

    Hidalgo, Paola Rodriguez; Eracleous, Michael; Charlton, Jane; Hamann, Fred; Murphy, Michael T.; Nestor, Daniel

    2013-09-20

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

  16. Effect of line, soaking and cooking time on water absorption, texture and splitting of red kidney beans.

    PubMed

    Zamindar, Nafiseh; Baghekhandan, Mohamad Shahedi; Nasirpour, Ali; Sheikhzeinoddin, Mahmoud

    2013-02-01

    Dry beans are rich sources of dietary fiber and phytochemicals such as flavonoids and phenolics that exhibit good functional properties. In current study line, cooking and soaking time effects were investigated on water absorption, splitting and texture of different Iranian red kidney beans to determine the best lines and the best soaking time related to them for industrial use. D81083 line had the highest level of water absorption after 24 h soaking followed by Akhtar and KS31164 lines while Azna, Goli and Naz lines had the lowest level of water absorption (p < 0.05). Akhtar and Sayyad had the highest level of splitting while KS31164 had the lowest level of splitting (p < 0.05). Soaking of Akhtar line for 24 h caused the highest level of water absorption accompanied with low splitting level. 24 h soaking and longer cooking time is recommended for Sayyad, while 12 h soaking and longer cooking time is recommended for KS31164 line. 24 h soaking causes higher level of water absorption and lower level of splitting in Derakhshan line. The effects of line, cooking and soaking time on red bean texture were significant (p < 0.01).

  17. Effect of line, soaking and cooking time on water absorption, texture and splitting of red kidney beans.

    PubMed

    Zamindar, Nafiseh; Baghekhandan, Mohamad Shahedi; Nasirpour, Ali; Sheikhzeinoddin, Mahmoud

    2013-02-01

    Dry beans are rich sources of dietary fiber and phytochemicals such as flavonoids and phenolics that exhibit good functional properties. In current study line, cooking and soaking time effects were investigated on water absorption, splitting and texture of different Iranian red kidney beans to determine the best lines and the best soaking time related to them for industrial use. D81083 line had the highest level of water absorption after 24 h soaking followed by Akhtar and KS31164 lines while Azna, Goli and Naz lines had the lowest level of water absorption (p < 0.05). Akhtar and Sayyad had the highest level of splitting while KS31164 had the lowest level of splitting (p < 0.05). Soaking of Akhtar line for 24 h caused the highest level of water absorption accompanied with low splitting level. 24 h soaking and longer cooking time is recommended for Sayyad, while 12 h soaking and longer cooking time is recommended for KS31164 line. 24 h soaking causes higher level of water absorption and lower level of splitting in Derakhshan line. The effects of line, cooking and soaking time on red bean texture were significant (p < 0.01). PMID:24425894

  18. THE VIEWING ANGLES OF BROAD ABSORPTION LINE VERSUS UNABSORBED QUASARS

    SciTech Connect

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

    2012-06-10

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

  19. X-Ray Continua of Broad Absorption Line Quasars

    NASA Technical Reports Server (NTRS)

    Mathur, S.

    1999-01-01

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

  20. Stark broadening of impurity absorption lines by inhomogeneous electric fields in highly compensated germanium

    NASA Astrophysics Data System (ADS)

    Harada, Y.; Fujii, K.; Ohyama, T.; Itoh, K. M.; Haller, E. E.

    1996-06-01

    Stark broadening of Zeeman absorption lines caused by inhomogeneous electric fields in highly compensated Ge has been studied by means of far-infrared magneto-optical absorption spectroscopy measurements. A number of transmutation-doped Ge single crystals with a systematically varying compensation ratio were employed. The broadening of the full width at half maximum (FWHM) of an absorption line of the Ga acceptor is studied as a function of excitation light intensity with above-band-gap energy. The FWHM increases with decreasing intensity of the band-edge light excitation. Observation of the theoretically predicted 4/3-power law of Stark broadening, due to ionized impurities, is reported. The line broadening originates in the Stark effect, due to inhomogeneous electric fields caused by the random distribution of ionized impurities. In order to understand the mechanism for the line broadening in detail, a numerical approach based on a Monte Carlo simulation has been performed. The results of this simulation show that the inhomogeneity of the field distribution becomes larger with increasing concentration of ionized impurities. The simulation based on a perfectly random distribution for an initial impurity arrangement gives a fairly good agreement with the experimental results. We conclude that the distribution of impurities in transmutation-doped Ge samples is close to random.

  1. Dust depletion of Ca and Ti in QSO absorption-line systems

    NASA Astrophysics Data System (ADS)

    Guber, C. R.; Richter, P.

    2016-06-01

    Aims: To explore the role of titanium- and calcium-dust depletion in gas in and around galaxies, we systematically study Ti/Ca abundance ratios in intervening absorption-line systems at low and high redshift. Methods: We investigate high-resolution optical spectra obtained by the UVES instrument at the Very Large Telescope (VLT) and spectroscopically analyze 34 absorption-line systems at z ≤ 0.5 to measure column densities (or limits) for Ca ii and Ti ii. We complement our UVES data set with previously published absorption-line data on Ti/Ca for redshifts up to z ~ 3.8. Our absorber sample contains 110 absorbers including damped Lyman α systems (DLAs), sub-DLAs, and Lyman-Limit systems (LLS). We compare our Ti/Ca findings with results from the Milky Way and the Magellanic Clouds and discuss the properties of Ti/Ca absorbers in the general context of quasar absorption-line systems. Results: Our analysis indicates that there are two distinct populations of absorbers with either high or low Ti/Ca ratios with a separation at [Ti/Ca] ≈ 1. While the calcium-dust depletion in most of the absorbers appears to be severe, the titanium depletions are mild in systems with high Ti/Ca ratios. The derived trend indicates that absorbers with high Ti/Ca ratios have dust-to-gas ratios that are substantially lower than in the Milky Way. We characterize the overall nature of the absorbers by correlating Ti/Ca with other observables (e.g., metallicity, velocity-component structure) and by modeling the ionization properties of singly-ionized Ca and Ti in different environments. Conclusions: We conclude that Ca ii and Ti ii bearing absorption-line systems trace predominantly neutral gas in the disks and inner halo regions of galaxies, where the abundance of Ca and Ti reflects the local metal and dust content of the gas. Our study suggests that the Ti/Ca ratio represents a useful measure for the gas-to-dust ratio and overall metallicity in intervening absorption-line systems.

  2. Neutral atomic absorption lines and far-UV extinction: Possible implications for depletions and grain parameters

    NASA Astrophysics Data System (ADS)

    Welty, Daniel E.

    1990-07-01

    Researchers examine nine lines of sight within the Galaxy and one in the Large Magellanic Cloud (LMC) for which data on both neutral atomic absorption lines (Snow 1984; White 1986; Welty, Hobbs, and York 1989) and far UV extinction (Bless and Savage 1972; Jenkins, Savage, and Spitzer 1986) are available, in order to test the assumption that variations in gamma/alpha will cancel in taking ratios of the ionization balance equation, and to try to determine to what extent that assumption has affected the aforementioned studies of depletions and grain properties.

  3. Neutral atomic absorption lines and far-UV extinction: Possible implications for depletions and grain parameters

    NASA Technical Reports Server (NTRS)

    Welty, Daniel E.

    1990-01-01

    Researchers examine nine lines of sight within the Galaxy and one in the Large Magellanic Cloud (LMC) for which data on both neutral atomic absorption lines (Snow 1984; White 1986; Welty, Hobbs, and York 1989) and far UV extinction (Bless and Savage 1972; Jenkins, Savage, and Spitzer 1986) are available, in order to test the assumption that variations in gamma/alpha will cancel in taking ratios of the ionization balance equation, and to try to determine to what extent that assumption has affected the aforementioned studies of depletions and grain properties.

  4. Tracing inflows and outflows with absorption lines in circumgalactic gas

    NASA Astrophysics Data System (ADS)

    Ford, Amanda Brady; Davé, Romeel; Oppenheimer, Benjamin D.; Katz, Neal; Kollmeier, Juna A.; Thompson, Robert; Weinberg, David H.

    2014-10-01

    We examine how H I and metal absorption lines within low-redshift galaxy haloes trace the dynamical state of circumgalactic gas, using cosmological hydrodynamic simulations that include a well-vetted heuristic model for galactic outflows. We categorize inflowing, outflowing, and ambient gas based on its history and fate as tracked in our simulation. Following our earlier work, showing that the ionization level of absorbers was a primary factor in determining the physical conditions of absorbing gas, we show here that it is also a governing factor for its dynamical state. Low-ionization metal absorbers (e.g. Mg II) tend to arise in gas that will fall on to galaxies within several Gyr, while high-ionization metal absorbers (e.g. O VI) generally trace material that was deposited by outflows many Gyr ago. Inflowing gas is dominated by enriched material that was previously ejected in an outflow; hence, accretion at low redshifts is typically substantially enriched. Recycling wind material is preferentially found closer to galaxies, and is more dominant in lower mass haloes since high-mass haloes have more hot gas that is able to support itself against infall. Low-mass haloes also tend to re-eject more of their accreted material, owing to our outflow prescription that employs higher mass loading factors for lower mass galaxies. Typical H I absorbers trace unenriched ambient material that is not participating in the baryon cycle, but stronger H I absorbers arise in cool, enriched inflowing gas. Instantaneous radial velocity measures of absorbers are generally poor at distinguishing between inflowing and outflowing gas, except in the case of very recent outflows. These results suggest that probing halo gas using a range of absorbers can provide detailed information about the amount and physical conditions of material that is participating in the baryon cycle.

  5. C IV Broad Absorption Line Variability in QSO spectra from SDSS I-III Surveys

    NASA Astrophysics Data System (ADS)

    De Cicco, D.; Brandt, W. N.; Paolillo, M.; Grier, C. J.

    2016-08-01

    We present the results of our study of C IV broad absorption line (BAL) variability in the spectra of more than 1500 QSO's from several SDSS I-III surveys. Absorption lines in QSO spectra are due to outflowing winds which originate from the accretion disk, at a distance on the order of 1/100 - 1/10 pc from the central super-massive black hole (SMBH). Winds trigger the accretion mechanism onto the SMBH removing angular momentum from the disk and, since they evacuate gas from the host galaxy, they are believed to play a fundamental role in galaxy evolution. Absorption lines can be classified on the basis of their width and of the observed transitions, and their equivalent width can change on timescales from months to years, due to variations in the covering factor and/or in the ionization level. We analyzed the largest sample ever used for such kind of studies. We find that the fraction of disappearing BALs is three times larger than the one found in previous works. Strong evidence is found for a coordinated variability in spectra with multiple BAL troughs which may be interpreted in terms of disk-wind rotation, and/or variations in the physical status of the shielding gas. We also find that, in spectra with multiple BAL troughs, the disappearing ones are generally those with the highest central velocity.

  6. What Drives the Outflows in Broad Absorption Line QSOs?

    NASA Technical Reports Server (NTRS)

    Begelman, Mitchell C.

    1997-01-01

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

  7. Line shape of 57Co sources exhibiting self absorption

    NASA Astrophysics Data System (ADS)

    Spiering, H.; Ksenofontov, V.; Leupold, O.; Kusz, J.; Deák, L.; Németh, Z.; Bogdán, C.; Bottyán, L.; Nagy, D. L.

    2016-12-01

    The effect of selfabsorption in Mössbauer sources is studied in detail. Spectra were measured using an old 57 C o/ R h source of 74 M B q activity with an original activity of ca. 3.7 G B q and a 0.15 G B q 57 C o/ α - F e source magnetized by an in-plane magnetic field of 0.2 T. The 57 C o/ α - F e source of a thickness of 25 μ was used both from the active and the inactive side giving cause to very different selfabsorption effects. The absorber was a single crystal of ferrous ammonium sulphate hexahydrate (FAS). Its absorption properties were taken over from a detailed study (Bull et al., Hyperfine Interact. 94(1-3), 1; Spiering et al. 2). FAS (space group P21/c) crystallizes as flat plates containing the (overline {2}01) plane. The γ-direction was orthogonal to the crystal plate. The 57 C o atoms of the 57 C o/ R h source were assumed to be homogeneously distributed over a 6 μ thick Rh foil and to follow a one dimensional diffusion profile in the 25 μ Fe-foil. The diffusion length was fitted to 10 μ. The theory follows the Blume-Kistner equations for forward scattering (Blume and Kistner, Phys. Rev. 171, 417, 3) by integrating over the source sampled up to 128 layers.

  8. The Hubble Space Telescope Quasar Absorption Line Key Project: The Unusual Absorption-Line System in the Spectrum of PG 2302+029--Ejected or Intervening?

    NASA Technical Reports Server (NTRS)

    Jannuzi, B. T.; Hartig, G. F.; Kirhakos, S.; Sargent, W. L. W.; Turnshek, D. A.; Weymann, R. J.; Bahcall, J. N.; Bergeron, J.; Boksenberg, A.; Savage, B. D.; Schneider, D. P.; Wolfe, A. M.

    1996-01-01

    We report the discovery of a high-ionization broad absorption line system at a redshift of z(sub abs) = 0.695 in the spectrum of the z(sub em) = 1.052 radio-quiet quasar PG 2302+029. Broad absorption with FWHM from 3000 to 5000 km/s is detected from C iv, N v, and O vi in Hubble Space Telescope (HST) Faint Object Spectrograph spectra of the quasar. A narrow-line system (FWHM approx. 250 km/s) at z(sub abs) = 0.7016 is resolved from the broad blend and includes absorption by Ly alpha and the C iv, N v, and O vi doublets. No absorption by low-ionization metal species (e.g., Si II and Mg II) is detected in the HST or ground-based spectra for either the broad or the narrow system. The centroids of the broad system lines are displaced by approx. 56,000 km/s to the blue of the quasar's broad emission lines. The reddest extent of the broad-line absorption is more than 50,000 km/s from the quasar. The properties of this system are unprecedented, whether it is an intervening or an ejected system.

  9. WAVELENGTH MEASUREMENTS OF K TRANSITIONS OF OXYGEN, NEON, AND MAGNESIUM WITH X-RAY ABSORPTION LINES

    SciTech Connect

    Liao Jinyuan; Zhang Shuangnan; Yao Yangsen

    2013-09-10

    Accurate atomic transition data are important in many astronomical research areas, especially for studies of line spectroscopy. Whereas transition data of He-like and H-like ions (i.e., ions in high-charge states) have been accurately calculated, the corresponding data of K transitions of neutral or low-ionized metal elements are still very uncertain. Spectroscopy of absorption lines produced in the interstellar medium (ISM) has been proven to be an effective way to measure the central wavelengths of these atomic transitions. In this work, we analyze 36 Chandra High Energy Transmission Grating observations to search for and measure the ISM absorption lines along sight lines to 11 low-mass X-ray binaries. We correct the Galactic rotation velocity to the rest frame for every observation and then use two different methods to merge all the corrected spectra to a co-added spectrum. However, the co-added spectra obtained by this method exhibit biases, toward to either observations with high counts or lines with high signal-to-noise ratios. We do a Bayesian analysis of several significantly detected lines to obtain the systematic uncertainty and the bias correction for other lines. Compared to previous studies, our results improve the wavelength accuracy by a factor of two to five and significantly reduce the systematic uncertainties and biases. Several weak transitions (e.g., 1s-2p of Mg IV and Mg V; 1s-3p of Mg III and Mg V) are also detected for the first time, albeit with low significance; future observations with improved accuracy are required to confirm these detections.

  10. Absorption Line Analysis to Interprete and Constrain Cosmological Simulations of Galaxy Evolution with Feedback

    NASA Astrophysics Data System (ADS)

    Churchill, Christopher

    2011-10-01

    The mammoth challenge for contemporary studies of galaxy formation and evolution are to establish detailed models in the cosmological context in which both the few parsec scale physics within galaxies are self-consistently unified and made consistent with the observed universe of galaxies. They key diagnostics reside with the gas physics, which dictate virtually every aspect of galaxy formation and evolution. The small scale physics includes stellar feedback, gas cooling, heating, and advection and the multiphase interstellar medium; the large scale physics includes intergalactic accretion, local merging, effects of supernovae driven winds, and the development of extended metal-enriched gas halos.Absorption line data have historically proven to be {and shall in the future} virtually the most powerful tool for understanding gas physics on all spatial scales over the majority of the age of the universe- the key to success. Simply stated, absorption lines are one of astronomy's most powerful observational windows on the universe {galaxy formation, galaxy winds, IGM metal enrichment, etc.}. The high quality and vast numbers of absorption line data {obtained with HST and FUSE} probe a broad range of gas structures {ISM, HVCs, halos, IGM} over the full cosmic span when galaxies are actively evolving.We propose to use LCDM hydrodynamic cosmological simulations employing a Eulerian Gasdynamics plus N-body Adaptive Refinement Tree {ART} code to develop and refine our understanding of stellar feedback physics and its role in governing the gas physics that regulates the evolution of galaxies and the IGM. We aim to substantially progress our understanding of all possible gas phases embedded within and extending far from galaxies. Our methodology is to apply a series of quantitative observational constraints from absorption line systems to better understand extended galaxy halos and the influence of the cosmological environment of the simulated galaxies: {1} galaxy halos

  11. Integrative fitting of absorption line profiles with high accuracy, robustness, and speed

    NASA Astrophysics Data System (ADS)

    Skrotzki, Julian; Habig, Jan Christoph; Ebert, Volker

    2014-08-01

    The principle of the integrative evaluation of absorption line profiles relies on the numeric integration of absorption line signals to retrieve absorber concentrations, e.g., of trace gases. Thus, it is a fast and robust technique. However, previous implementations of the integrative evaluation principle showed shortcomings in terms of accuracy and the lack of a fit quality indicator. This has motivated the development of an advanced integrative (AI) fitting algorithm. The AI fitting algorithm retains the advantages of previous integrative implementations—robustness and speed—and is able to achieve high accuracy by introduction of a novel iterative fitting process. A comparison of the AI fitting algorithm with the widely used Levenberg-Marquardt (LM) fitting algorithm indicates that the AI algorithm has advantages in terms of robustness due to its independence from appropriately chosen start values for the initialization of the fitting process. In addition, the AI fitting algorithm shows speed advantages typically resulting in a factor of three to four shorter computational times on a standard personal computer. The LM algorithm on the other hand retains advantages in terms of a much higher flexibility, as the AI fitting algorithm is restricted to the evaluation of single absorption lines with precomputed line width. Comparing both fitting algorithms for the specific application of in situ laser hygrometry at 1,370 nm using direct tunable diode laser absorption spectroscopy (TDLAS) suggests that the accuracy of the AI algorithm is equivalent to that of the LM algorithm. For example, a signal-to-noise ratio of 80 and better typically yields a deviation of <1 % between both fitting algorithms. The properties of the AI fitting algorithm make it an interesting alternative if robustness and speed are crucial in an application and if the restriction to a single absorption line is possible. These conditions are fulfilled for the 1,370 nm TDLAS hygrometry at the

  12. Is there a connection between broad absorption line quasars and narrow-line Seyfert 1 galaxies?

    SciTech Connect

    Grupe, Dirk; Nousek, John A.

    2015-02-01

    We consider whether broad absorption line quasars (BAL QSOs) and narrow-line Seyfert 1 galaxies (NLS1s) are similar, as suggested by Brandt and Gallagher and Boroson. For this purpose, we constructed a sample of 11 BAL QSOs from existing Chandra and Swift observations. We found that BAL QSOs and NLS1s both operate at high Eddington ratios L/L{sub Edd}, although BAL QSOs have slightly lower L/L{sub Edd}. BAL QSOs and NLS1s in general have high Fe ii/Hβ and low [O iii]/Hβ ratios following the classic “Boroson and Green” eigenvector 1 relation. We also found that the mass accretion rates M-dot of BAL QSOs and NLS1s are more similar than previously thought, although some BAL QSOs exhibit extreme mass accretion rates of more than 10 M{sub ⊙} yr{sup −1}. These extreme mass accretion rates may suggest that the black holes in BAL QSOs are relativistically spinning. Black hole masses in BAL QSOs are a factor of 100 larger than NLS1s. From their location on a M−σ plot, we find that BAL QSOs contain fully developed black holes. Applying a principal component analysis to our sample, we find eigenvector 1 to correspond to the Eddington ratio L/L{sub Edd}, and eigenvector 2 to black hole mass.

  13. Foreign-gas broadening of nitrous oxide absorption lines.

    NASA Technical Reports Server (NTRS)

    Tubbs, L. D.; Williams, D.

    1972-01-01

    We have measured the foreign-gas broadening coefficients for collisional broadening of lines in the nu-3 fundamental of N2O by He, Ne, Ar, Kr, Xe, H2, D2, and CH4. These coefficients, which give the ratio of the line-broadening ability of these gases to the line-broadening ability of N2, can be used with recent measurements and calculations of N2 broadening to obtain optical collision cross sections.

  14. In-line absorption sensor based on coiled optical microfiber

    NASA Astrophysics Data System (ADS)

    Lorenzi, Roberto; Jung, Yongmin; Brambilla, Gilberto

    2011-04-01

    We fabricated and tested an evanescent-wave absorption sensor consisting of an optical microfiber coil resonator embedded in fluidic channel walls. Low concentrations of flowing analyte show optical losses in agreement with a modified Beer-Lambert law. Higher concentration causes a limit value of the measured optical losses arising from adsorption mechanisms.

  15. The Discovery of the First He Iλ10830 Broad Absorption Line Quasar

    NASA Astrophysics Data System (ADS)

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

    2011-02-01

    We report the discovery of the first He I*λ10830 broad absorption line quasar FBQS J1151+3822. Using new infrared and optical spectra, as well as the SDSS spectrum, we extracted the apparent optical depth profiles as a function of velocity of the 3889 Å and 10830 Å He I* absorption lines. Since these lines have the same lower levels, inhomogeneous absorption models could be used to extract the average true He I* column density; the log of that number was 14.9. The total hydrogen column density was obtained using Cloudy models. A range of ionization parameters and densities were allowed, with the lower limit on the ionization parameter of log U = -1.4 determined by the requirement that there be sufficient He I*, and the upper limit on the density of log n = 8 determined by the lack of Balmer absorption. Simulated UV spectra showed that the ionization parameter could be further constrained in principle using a combination of low- and high-ionization lines (such as Mg II and P V), but the only density-sensitive line predicted to be observable and not significantly blended was C IIIλ1176. We estimated the outflow rate and kinetic energy, finding them to be consistent but on the high side compared with analyses of other objects. Assuming that radiative line driving is the responsible acceleration mechanism, a force multiplier model was constructed. A dynamical argument using the model results strongly constrained the density to be log n >= ~7. Consequently, the log hydrogen column density is constrained to be between 21.7 and 22.9, the mass outflow rate to be between 11 and 56 solar masses per year, the ratio of the mass outflow rate to the accretion rate to be between 1.2 and 5.8, and the kinetic energy to be between 1 and 5 × 1044 erg s-1. We discuss the advantages of using He I* to detect high column density BALQSOs and measure their properties. We find that the large λfik ratio of 23.3 between the 10830 Å and 3889 Å components makes He I* analysis sensitive

  16. Effect of a progressive sound wave on the profiles of spectral lines. 2: Asymmetry of faint Fraunhofer lines. [absorption spectra

    NASA Technical Reports Server (NTRS)

    Kostyk, R. I.

    1974-01-01

    The absorption coefficient profile was calculated for lines of different chemical elements in a medium with progressive sound waves. Calculations show that (1) the degree and direction of asymmetry depend on the atomic ionization potential and the potential of lower level excitation of the individual line; (2) the degree of asymmetry of a line decreases from the center toward the limb of the solar disc; and (3) turbulent motions 'suppress' the asymmetry.

  17. Radio line and continuum observations of quasar-galaxy pairs and the origin of low reshift quasar absorption line systems

    NASA Technical Reports Server (NTRS)

    Carilli, C. L.; Vangorkom, J. H.; Hauxthausen, E. M.; Stocke, J. T.; Salzer, J.

    1990-01-01

    There are a number of known quasars for which our line of sight to the high redshift quasar passes within a few Holmberg radii of a low redshift galaxy. In a few of these cases, spectra of the quasar reveal absorption by gas associated with the low redshift galaxy. A number of these pairs imply absorption by gas which lies well outside the optical disk of the associated galaxy, leading to models of galaxies with 'halos' or 'disks' of gas extending to large radii. The authors present observations of 4 such pairs. In three of the four cases, they find that the associated galaxy is highly disturbed, typically due to a gravitational interaction with a companion galaxy, while in the fourth case the absorption can be explained by clouds in the optical disk of the associated galaxy. They are led to an alternative hypothesis concerning the origin of the low redshift absorption line systems: the absorption is by gas clouds which have been gravitationally stripped from the associated galaxy. These galaxies are rapidly evolving, and should not be used as examples of absorption by clouds in halos of field spirals. The authors conclude by considering the role extended gas in interacting systems plays in the origin of higher redshift quasar absorption line systems.

  18. VizieR Online Data Catalog: AGN data and absorption-line measurements (Richter+, 2016)

    NASA Astrophysics Data System (ADS)

    Richter, P.; Wakker, B. P.; Fechner, C.; Herenz, P.; Tepper-Garcia, T.; Fox, A. J.

    2016-03-01

    Names, positions and emission redshifts for 303 QSOs are provided in Table A.1. Table A.2 summarizes the absorption-line measurements for 59 intervening SiIII absorbers including absorption redshifts, equivalent-widths, and column densities for various different ions. (2 data files).

  19. Effects of velocity averaging on the shapes of absorption lines

    NASA Technical Reports Server (NTRS)

    Pickett, H. M.

    1980-01-01

    The velocity averaging of collision cross sections produces non-Lorentz line shapes, even at densities where Doppler broadening is not apparent. The magnitude of the effects will be described using a model in which the collision broadening depends on a simple velocity power law. The effect of the modified profile on experimental measures of linewidth, shift and amplitude will be examined and an improved approximate line shape will be derived.

  20. An ALMA Early Science survey of molecular absorption lines toward PKS 1830-211. Analysis of the absorption profiles

    NASA Astrophysics Data System (ADS)

    Muller, S.; Combes, F.; Guélin, M.; Gérin, M.; Aalto, S.; Beelen, A.; Black, J. H.; Curran, S. J.; Darling, J.; V-Trung, Dinh; García-Burillo, S.; Henkel, C.; Horellou, C.; Martín, S.; Martí-Vidal, I.; Menten, K. M.; Murphy, M. T.; Ott, J.; Wiklind, T.; Zwaan, M. A.

    2014-06-01

    We present the first results of an ALMA spectral survey of strong absorption lines for common interstellar species in the z = 0.89 molecular absorber toward the lensed blazar PKS 1830-211. The dataset brings essential information on the structure and composition of the absorbing gas in the foreground galaxy. In particular, we find absorption over large velocity intervals (≳100 km s-1) toward both lensed images of the blazar. This suggests either that the galaxy inclination is intermediate and that we sample velocity gradients or streaming motions in the disk plane, that the molecular gas has a large vertical distribution or extraplanar components, or that the absorber is not a simple spiral galaxy but might be a merger system. The number of detected species is now reaching a total of 42 different species plus 14 different rare isotopologues toward the SW image, and 14 species toward the NE line-of-sight. The abundances of CH, H2O, HCO+, HCN, and NH3 relative to H2 are found to be comparable to those in the Galactic diffuse medium. Of all the lines detected so far toward PKS 1830-211, the ground-state line of ortho-water has the deepest absorption. We argue that ground-state lines of water have the best potential for detecting diffuse molecular gas in absorption at high redshift. Appendix is available in electronic form at http://www.aanda.orgThe reduced spectrum (FITS format) is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/566/A112

  1. On-Line Wavelength Calibration of Pulsed Laser for CO2 Differential Absorption LIDAR

    NASA Astrophysics Data System (ADS)

    Xiang, Chengzhi; Ma, Xin; Han, Ge; Liang, Ailin; Gong, Wei

    2016-06-01

    Differential absorption lidar (DIAL) remote sensing is a promising technology for atmospheric CO2 detection. However, stringent wavelength accuracy and stability are required in DIAL system. Accurate on-line wavelength calibration is a crucial procedure for retrieving atmospheric CO2 concentration using the DIAL, particularly when pulsed lasers are adopted in the system. Large fluctuations in the intensities of a pulsed laser pose a great challenge for accurate on-line wavelength calibration. In this paper, a wavelength calibration strategy based on multi-wavelength scanning (MWS) was proposed for accurate on-line wavelength calibration of a pulsed laser for CO2 detection. The MWS conducted segmented sampling across the CO2 absorption line with appropriate number of points and range of widths by using a tunable laser. Complete absorption line of CO2 can be obtained through a curve fitting. Then, the on-line wavelength can be easily found at the peak of the absorption line. Furthermore, another algorithm called the energy matching was introduced in the MWS to eliminate the backlash error of tunable lasers during the process of on-line wavelength calibration. Finally, a series of tests was conducted to elevate the calibration precision of MWS. Analysis of tests demonstrated that the MWS proposed in this paper could calibrate the on-line wavelength of pulsed laser accurately and steadily.

  2. CRIRES spectroscopy and empirical line-by-line identification of FeH molecular absorption in an M dwarf

    NASA Astrophysics Data System (ADS)

    Wende, S.; Reiners, A.; Seifahrt, A.; Bernath, P. F.

    2010-11-01

    Molecular FeH provides a large number of sharp and isolated absorption lines that can be used to measure radial velocity, rotation, or magnetic field strength with high accuracy. Our aim is to provide an FeH atlas for M-type stars in the spectral region from 986 nm to 1077 nm (Wing-Ford band). To identify these lines in CRIRES spectra of the magnetically inactive, slowly rotating, M5.5 dwarf GJ1002, we calculated model spectra for the selected spectral region with theoretical FeH line data. In general this line list agrees with the observed data, but several individual lines differ significantly in position or in line strength. After identification of as many as possible FeH lines, we corrected the line data for position and line strength to provide an accurate atlas of FeH absorption lines for use in high precision spectroscopy of low mass stars. For all lines, we used a Voigt function to obtain their positions and equivalent widths. Identification with theoretical lines was done by hand. For confirmation of the identified lines, we used statistical methods, cross-correlation techniques, and line intensities. Eventually, we were able to identify FeH lines from the (0,0), (1,0), (1,1), (2,1), (2,2), (3,2), and (4,3) vibrational bands in the observed spectra and correct the positions of the lines if necessary. The deviations between theoretical and observed positions follow a normal distribution approximately around zero. In order to empirically correct the line strength, we determined Teff, instrumental broadening (rotational broadening) and a van der Waals enhancement factor for the FeH lines in GJ1002. We also give the scaling factors for the Einstein A values to correct the line strengths. With the identified lines, we derived rotational temperatures from the line intensities for GJ1002. We conclude that FeH lines can be used for a wide variety of applications in astrophysics. With the identified lines it will be possible for example to characterize magnetically

  3. The Physical Nature of Weak MgII Quasar Absorption Line Systems.

    NASA Astrophysics Data System (ADS)

    Narayanan, Anand

    2007-12-01

    In a span of four decades, quasar absorption line spectroscopy has emerged as one of the most efficient methods for probing HI gas and associated metals in a wide range of environments, from redshifts corresponding to the most distant quasars up to the present. The connection between strong MgII quasar absorption systems and the disks/halos of galaxies of various morphologies is fairly well established. In contrast, the physical nature of weak MgII absorbers is not sufficiently understood. In this talk, I will present results from my dissertation work, which is a study of weak MgII quasar absorption line systems at 01), could be gas clouds in the extended halos of galaxies, analogous to the Milky Way high velocity clouds. The gas might correspond to material expelled from rapidly star-forming galaxies in correlated supernova events. Some fraction of the population of weak MgII clouds can also arise along sight lines that intercept tidally stripped interstellar gas, residing in circumgalactic environments. The `iron-rich’ weak MgII clouds, which are prevalent at lower redshifts (z<1), must be tracing Type Ia enriched gas in sites that have been previously enriched by star formation, most likely in dwarf galaxies. These scenarios will be reviewed in my presentation. This work is supported by NSF. I thankfully acknowledge the Zaccheus Daniel Foundation and Sigma Xi for providing generous travel support.

  4. Metal-line absorption at Z(sub abs) approximately Z(sub em) from associated galaxies

    NASA Technical Reports Server (NTRS)

    Ellingson, E.; Yee, H. K. C.; Bechtold, Jill; Dobrzycki, Adam

    1994-01-01

    For a preliminary study of whether C IV absorption at Z(sub abs) approximately Z(sub em) is related to associated galaxy companions, we have collected data from a sample of 10 quasars with 0.15 less than z less than 0.65 for which high-resolution optical and UV spectroscopy is available from the literature, and for which we have deep optical images and limited spectroscopy. We also present new optical spectra for two of our samples. Four of these quasars have associated C IV absorption systems. In thes four fields, there are eight galaxies with M(sub r) less than -19.0 mag within 35 kpc of the quasar (projected distance, assuming they are at the quasar redshift), which may be candidates for the associated C IV absorption. This observed density of galaxies near quasars with associated C IV absorption is significantly greater than that for a control sample of quasars chosen from the literature. This result suggests that galaxies near the quasar line of sight may be linked with associated C IV absorption. None of these quasars show associated Mg II absorption, despite the presence of galaxies very near the line of sight, suggesting a Mg II 'proximity effect,' where ionizing flux from the quasar destroys the Mg(+) from at least the outer parts of the galaxies. Three quasars are located in rich galaxy clusters, but none of these quasars are found to have associated C IV absorption. This suggests that galaxies in rich clusters associated with quasars are less likely to be metal-line absorbers. It is plausible that the extended galaxy halos which may be responsible for the absorptions are stripped from galaxies in these dense environments. While it seems that at Z approximately 0.6 rich clusters do not cause them, associated C IV absorption systems at higher redshift may be explained by associated clusters if there has been evolution in the properties of galaxy halos in dense environments.

  5. Detectability of cold streams into high-redshift galaxies by absorption lines

    NASA Astrophysics Data System (ADS)

    Goerdt, Tobias; Dekel, Avishai; Sternberg, Amiel; Gnat, Orly; Ceverino, Daniel

    2012-08-01

    Cold gas streaming along the dark matter filaments of the cosmic web is predicted to be the major source of fuel for disc buildup, violent disc instability and star formation in massive galaxies at high redshift. We investigate to what extent such cold gas is detectable in the extended circumgalactic environment of galaxies via Lyα absorption and selected low-ionization metal absorption lines. We model the expected absorption signatures using high-resolution zoom-in adaptive mesh refinement cosmological simulations. In the post-processing, we distinguish between self-shielded gas and unshielded gas. In the self-shielded gas, which is optically thick to Lyman continuum radiation, we assume pure collisional ionization for species with an ionization potential greater than 13.6 eV. In the optically-thin, unshielded gas, these species are also photoionized by the metagalactic radiation. In addition to absorption of radiation from background quasars, we compute the absorption line profiles of radiation emitted by the galaxy at the centre of the same halo. We predict the strength of the absorption signal for individual galaxies without stacking. We find that the Lyα absorption profiles produced by the streams are consistent with observations of absorption and emission Lyα profiles in high-redshift galaxies. Due to the low metallicities in the streams, and their low covering factors, the metal absorption features are weak and difficult to detect.

  6. Discovery of Extremely Broad Balmer Absorption Lines in SDSS J152350.42+391405.2

    NASA Astrophysics Data System (ADS)

    Zhang, Shaohua; Zhou, Hongyan; Shi, Xiheng; Shu, Xinwen; Liu, Wenjuan; Ji, Tuo; Jiang, Peng; Sun, Luming; Zhou, Junyan; Pan, Xiang

    2015-12-01

    We present the discovery of Balmer line absorption from Hα to Hγ in an iron low-ionization broad absorption line (FeLoBAL) quasar SDSS J152350.42+391405.2 (hereafter SDSS J1523+3914), by the quasi-simultaneous optical and near-infrared spectroscopy. The Balmer line absorption is at {z}{absor}=0.6039+/- 0.0021 and blueshifted by v = 10,353 km s-1 with respect to the Balmer emission lines. All Balmer BALs have a uniform absorption profile with the widths of {{Δ }}v˜ 12,000 km s-1. We also found the absorption trough in He i* λ10830 with the same velocity and width in the H-band TripleSpec spectrum of SDSS J1523+3914. This object is only the 10th active galactic nucleus known to exhibit nonstellar Balmer absorption, as well as the case with the highest velocity and broadest Balmer absorption lines that have ever been found. A CLOUDY analysis shows that the absorbers require a gas density of {{log}}10 {n}{{e}} ({{cm}}-3)=9 and an ionization parameter of {{log}}10 U=-1.0. They are located at a distance of ˜0.2 pc from the central ionizing source, which is slightly farther than that of broad emission line regions. Furthermore, SDSS J1523+3914 is one of the brightest Balmer BAL quasars ever reported, with unique iron absorption variations, making it the most promising candidate for follow-up high-resolution spectroscopy, multiband observations, and long-term monitoring.

  7. THE JHU-SDSS METAL ABSORPTION LINE CATALOG: REDSHIFT EVOLUTION AND PROPERTIES OF Mg II ABSORBERS

    SciTech Connect

    Zhu Guangtun; Menard, Brice

    2013-06-20

    We present a generic and fully automatic method aimed at detecting absorption lines in the spectra of astronomical objects. The algorithm estimates the source continuum flux using a dimensionality reduction technique and nonnegative matrix factorization, and then detects and identifies metal absorption lines. We apply it to a sample of {approx}10{sup 5} quasar spectra from the Sloan Digital Sky Survey and compile a sample of {approx}40,000 Mg II- and Fe II-absorber systems, spanning the redshift range 0.4 < z < 2.3. The corresponding catalog is publicly available. We study the statistical properties of these absorber systems and find that the rest equivalent width distribution of strong Mg II absorbers follows an exponential distribution at all redshifts, confirming previous studies. Combining our results with recent near-infrared observations of Mg II absorbers, we introduce a new parameterization that fully describes the incidence rate of these systems up to z {approx} 5. We find the redshift evolution of strong Mg II absorbers to be remarkably similar to the cosmic star formation history over 0.4 < z < 5.5 (the entire redshift range covered by observations), suggesting a physical link between these two quantities.

  8. The Milky Way's Hot Gas Kinematics: Signatures in Current and Future OVII Absorption Line Observations

    NASA Astrophysics Data System (ADS)

    Miller, Matthew J.; Hodges-Kluck, Edmund J.; Bregman, Joel N.

    2016-02-01

    Detections of z ≈ 0 oxygen absorption and emission lines indicate the Milky Way hosts a hot (˜ {10}6 K), low-density plasma extending ≳ 50 {{kpc}} into the Mily Way’s halo. Current X-ray telescopes cannot resolve the line profiles, but the variation of their strengths on the sky constrains the radial gas distribution. Interpreting the O vii Kα absorption line strengths has several complications, including optical depth and line of sight velocity effects. Here, we present model absorption line profiles accounting for both of these effects to show the lines can exhibit asymmetric structures and be broader than the intrinsic Doppler width. The line profiles encode the hot gas rotation curve, the net inflow or outflow of hot gas, and the hot gas angular momentum profile. We show how line of sight velocity effects impact the conversion between equivalent width and the column density, and provide modified curves of growth accounting for these effects. As an example, we analyze the LMC sight line pulsar dispersion measure and O vii equivalent width to show the average gas metallicity is ≳ 0.6{Z}⊙ and b ≳ 100 km s-1. Determining these properties offers valuable insights into the dynamical state of the Milky Way’s hot gas, and improves the line strength interpretation. We discuss future strategies to observe these effects with an instrument that has a spectral resolution of about 3000, a goal that is technically possible today.

  9. Determination of the width of the absorption line of atomic iodine in optimization of the parameters of an iodine switch

    SciTech Connect

    Eroshenko, V.A.; Kirillov, G.A.; Mochalov, M.R.; Shemyakin, V.I.; Shurygin, V.K.

    1981-09-01

    A theoretical basis is given for the optimization of the parameters of an iodine switch. The results are reported of an experimental study of the pressure dependence of the width of the absorption line of atomic iodine. The broadening coefficient of molecular iodine is 3.2 MHz/Torr in the temperature range 800--1000 /sup 0/C.

  10. Absorption-line systems in simulated galaxies fed by cold streams

    NASA Astrophysics Data System (ADS)

    Fumagalli, Michele; Prochaska, J. Xavier; Kasen, Daniel; Dekel, Avishai; Ceverino, Daniel; Primack, Joel R.

    2011-12-01

    Hydro-cosmological simulations reveal that massive galaxies at high redshift are fed by long narrow streams of merging galaxies and a smoother component of cold gas. We post-process seven high-resolution simulated galaxies with radiative transfer to study the absorption characteristics of the gas in galaxies and streams, in comparison with the statistics of observed absorption-line systems. We find that much of the stream gas is ionized by UV radiation from background and local stellar sources, but still optically thick (? cm-2) so that the streams appear as Lyman-limit systems (LLSs). At z > 3, the fraction of neutral gas in streams becomes non-negligible, giving rise to damped Lyman α absorbers (DLAs) as well. The gas in the central and incoming galaxies remains mostly neutral, responsible for DLAs. Within one (two) virial radii, the covering factor of optically thick gas is <25 per cent (10 per cent) for LLSs and <5 per cent (1 per cent) for DLAs, slowly declining with time following the universal expansion. Nevertheless, galaxies and their cold streams in the studied mass range, Mvir= 1010-1012 M⊙, account for >30 per cent of the observed absorbers in the foreground of quasars, the rest possibly arising from smaller galaxies or the intergalactic medium. The mean metallicity in the streams is ˜1 per cent solar, much lower than in the galaxies. The simulated galaxies reproduce the Lyα-absorption equivalent widths observed around Lyman-break galaxies, but they severely underpredict the equivalent widths in metal lines, suggesting that the latter may arise from outflows. We conclude that the observed metal-poor LLSs are likely detections of the predicted cold streams. Revised analysis of the observed LLSs kinematics and simulations with more massive outflows in conjunction with the inflows may enable a clearer distinction between the signatures of the various gas modes.

  11. Solvent drag effect in drug intestinal absorption. II. Studies on drug absorption clearance and water influx.

    PubMed

    Karino, A; Hayashi, M; Awazu, S; Hanano, M

    1982-09-01

    In order to study the solvent drag effect, it was shown that back flux of absorbed drug from blood to intestinal lumen can be ignored but the back flux of water cannot. Then, apparent water influx was calculated as a new measure of solvent drag based on the model in which the back flux of D2O from blood to lumen was considered during absorption. Consequently, the correlation between drug absorption clearance (CLdrug) and apparent water influx was highly significant for benzoic acid, salicylic acid, p-hydroxybenzoic acid, antipyrine, cephalexin (CEX) and cefroxadine (CXD), resulting the high solvent drag effects were detected. The mean values of the slopes in the regression lines of CLdrug versus apparent water influx, i.e., sieving coefficients, were smaller than one for benzoic acid and salicylic acid, but the values were not significantly different from one. The sieving coefficients of the other drugs were significantly smaller than one. From these results, the molecular size dependence in the reflection from the intestinal membrane during absorption was clearly shown. And the intercepts of the regression lines including diffusive permeabilities were found to be significantly different from zero in CEX and CXD. On the basis of the sieving coefficients and intercept values obtained in such ways, the appropriateness of this model was discussed.

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

    SciTech Connect

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

    2010-09-01

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

  13. Laboratory verification of on-line lithium analysis using ultraviolet absorption spectrometry

    SciTech Connect

    Beemster, B.J.; Schlager, K.J.; Schloegel, K.M.; Kahle, S.J.; Fredrichs, T.L.

    1992-12-31

    Several laboratory experiments were performed to evaluate the capability of absorption spectrometry in the ultraviolet-visible wavelength range with the objective of developing methods for on-line analysis of lithium directly in the primary coolant of Pressurized Water Reactors using optical probes. Although initial laboratory tests seemed to indicate that lithium could be detected using primary absorption (detection of natural spectra unassisted by reagents), subsequent field tests demonstrated that no primary absorption spectra existed for lithium in the ultraviolet-visible wavelength range. A second series of tests that were recently conducted did, however, confirm results reported in the literature to the effect that reagents were available that will react with lithium to form chelates that possess detectable absorption and fluorescent signatures. These results point to the possible use of secondary techniques for on-line analysis of lithium.

  14. EMPIRICAL LINE LISTS AND ABSORPTION CROSS SECTIONS FOR METHANE AT HIGH TEMPERATURES

    SciTech Connect

    Hargreaves, R. J.; Bernath, P. F.; Dulick, M.; Bailey, J.

    2015-11-01

    Hot methane is found in many “cool” sub-stellar astronomical sources including brown dwarfs and exoplanets, as well as in combustion environments on Earth. We report on the first high-resolution laboratory absorption spectra of hot methane at temperatures up to 1200 K. Our observations are compared to the latest theoretical spectral predictions and recent brown dwarf spectra. The expectation that millions of weak absorption lines combine to form a continuum, not seen at room temperature, is confirmed. Our high-resolution transmittance spectra account for both the emission and absorption of methane at elevated temperatures. From these spectra, we obtain an empirical line list and continuum that is able to account for the absorption of methane in high temperature environments at both high and low resolution. Great advances have recently been made in the theoretical prediction of hot methane, and our experimental measurements highlight the progress made and the problems that still remain.

  15. Low-redshift Lyman-alpha absorption lines and the dark matter halos of disk galaxies

    NASA Technical Reports Server (NTRS)

    Maloney, Philip

    1992-01-01

    Ultraviolet observations of the low-redshift quasar 3C 273 using the Hubble Space Telescope have revealed many more Lyman-alpha absorption lines than would be expected from extrapolation of the absorption systems seen toward QSOs at z about 2. It is shown here that these absorption lines can plausibly be produced by gas at large radii in the disks of spiral and irregular galaxies; the gas is confined by the dark matter halos and ionized and heated by the extragalactic radiation field. This scenario does not require the extragalactic ionizing radiation field to decline as rapidly with decreasing z as the QSO emissivity. Observations of Ly-alpha absorption through the halos of known galaxies at low redshift will constrain both the extragalactic background and the properties of galactic halos.

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

    SciTech Connect

    Pettini, M.; Boksenberg, A.

    1985-07-01

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

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

    NASA Technical Reports Server (NTRS)

    Beltrametti, M.

    1980-01-01

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

  18. Modelling of the X-ray broad absorption features in Narrow-Line Seyfert 1s

    NASA Astrophysics Data System (ADS)

    Porquet, Delphine; Mouchet, Martine; Dumont Anne-Marie

    2000-09-01

    We investigate the origin of the broad absorption features detected near 1-1.4 keV in several Narrow-Line Seyfert 1 galaxies, by modelling the absorbing medium with various physical parameters, using the ionization code PEGAS. The observed properties of the X-ray absorption features can be reproduced by taking into account the peculiar soft X-ray excess which is well fitted by a blackbody plus an underlying power law. We equally stress that the emission coming from the absorbing medium (related to the covering factor) has a strong influence on the resulting X-ray spectrum, in particular on the apparent position and depth of the absorption features. A non-solar iron abundance may be required to explain the observed deep absorption. We also investigate the influence of an additional collisional ionization process ("hybrid case") on the predicted absorption features.

  19. {ital Hubble Space Telescope} Observations of the Broad Absorption Line Quasar PG 0946+301

    SciTech Connect

    Arav, N.; Korista, K.T. |; de Kool, M. |; Junkkarinen, V.T.; Begelman, M.C.

    1999-05-01

    We analyze {ital Hubble Space Telescope} ({ital HST}) and ground-based spectra of the brightest broad absorption line (BAL) quasar in the UV: PG 0946+301. A detailed study of the absorption troughs as a function of velocity is presented, facilitated by the use of a new algorithm to solve for the optical depth as a function of velocity for multiplet lines. We find convincing evidence for saturation in parts of the troughs. This supports our previous assertion that saturation is common in BALs and therefore cast doubts on claims for very high metallicity in BAL flows. Because of the importance of BAL saturation we also discuss its evidence in other objects. In PG 0946+301 large differences in ionization as a function of velocity are detected, and our findings support the hypothesis that the line of sight intersects a number of flow components that combine to give the appearance of the whole trough. Based on the optical depth profiles, we develop a geometrical-kinematical model for the flow. We have positively identified 16 ions of eight elements (H i, C iii, C iv, N iii, N iv, N v, O iii, O iv, O v, O vi, Ne v, Ne viii, P v, Si iv, S v, S vi) and have probable identifications of Mg x and S iv. Unlike earlier analysis of {ital IUE} data, we find no evidence for BALs arising from excited ionic states in the {ital HST} spectrum of PG 0946+301. {copyright} {ital {copyright} 1999.} {ital The American Astronomical Society}

  20. The η Car Campaign with UVES at the ESO VLT II. Interstellar and circumstellar absorption lines

    NASA Astrophysics Data System (ADS)

    Weis, K.; Bomans, D. J.; Stahl, O.; Davidson, K.; Humphreys, R. M.; Gull, T. R.

    2005-09-01

    We monitored η Car and the Homunculus using the ESO VLT UVES spectrograph between 2002 and 2004 (see Weis et al., this proceedings). In these high dispersion spectra practically all interstellar absorption features known in the 3000 Å to 10000 Å regime are present (e.g. 4 Ti II lines, 3 Fe I lines, the Ca I line, both Na I doublets, the two K I doublets, and the Ca II doublets, several molecular lines, and a number of diffuse interstellar bands). Near-UV STIS spectra show many low ionization absorption lines (e.g. Gull et al., this proceedings), but there are several differences in the velocity structure and line strengths between these lines of sight, e.g. we do not detect multiple absorption components between -350 to -550 km s-1 in the UVES spectra. Changes over time are present in e.g. the Ca II lines, with small column density changes in the (probably interstellar) +80 km s-1 component and large changes in the -510 km s-1 component, which is most probably located in the outer shell of the Homunculus (see e.g. Nielsen et al., this proceedings). Similar changes in the Ti II 3384 Å component at -147 km s-1 are present, too. With the data set, we not only follow the temporal evolution of the circumstellar absorption components (presumably originating near η Car and in the Homunculus) before, during and after the event, but also search for changes along our long-slits centered on the star and on FOS4. Indeed, the -147 km s-1 component of the Ti II 3384 Å lines shows line strength variations over the southeast lobe of the Homunculus. A preliminary search for very high velocity absorption lines from the outer ejected using only one of our spectra already yielded a possible detection at -1500 km s-1. Clearly a detailed analysis of the absorption lines in the UVES data will provide many new insights into the structure and physics of η Car's ejecta.

  1. Narrow absorption lines with two observations from the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Chen, Zhi-Fu; Gu, Qiu-Sheng; Chen, Yan-Mei; Cao, Yue

    2015-07-01

    We assemble 3524 quasars from the Sloan Digital Sky Survey (SDSS) with repeated observations to search for variations of the narrow C IV λ λ 1548,1551 and Mg II λ λ 2796,2803 absorption doublets in spectral regions shortward of 7000 Å in the observed frame, which corresponds to time-scales of about 150-2643 d in the quasar rest frame. In these quasar spectra, we detect 3580 C IV absorption systems with zabs = 1.5188-3.5212 and 1809 Mg II absorption systems with zabs = 0.3948-1.7167. In term of the absorber velocity (β) distribution in the quasar rest frame, we find a substantial number of C IV absorbers with β < 0.06, which might be connected to absorption of quasar outflows. The outflow absorption peaks at υ ≈ 2000 km s^{-1} and drops rapidly below this peak value. Among 3580 C IV absorption systems, 52 systems (˜1.5 per cent) show obvious variations in equivalent widths in the absorber rest frame (Wr): 16 enhanced, 16 emerged, 12 weakened and 8 disappeared systems, respectively. We find that changes in Wrλ1548 are related neither to the time-scales of the two SDSS observations nor to absorber velocities in the quasar rest frame. Variable absorption in low-ionization species is important to constrain the physical conditions of the absorbing gas. There are two variable Mg II absorption systems measured from SDSS spectra detected by Hacker et al. However, in our Mg II absorption sample, we find that neither shows variable absorption with confident levels of >4σ for λ2796 lines and >3σ for λ2803 lines.

  2. VizieR Online Data Catalog: QSOs narrow absorption line variability (Hacker+, 2013)

    NASA Astrophysics Data System (ADS)

    Hacker, T. L.; Brunner, R. J.; Lundgren, B. F.; York, D. G.

    2013-06-01

    Catalogues of 2,522 QAL systems and 33 variable NAL systems detected in SDSS DR7 quasars with repeat observations. The object identifiers, position coordinates, and plate-MJD-fibre designations are taken from the SpecObjAll table in the SDSS Catalogue Archive Server (CAS) while the quasar redshifts (zqso) are from Hewett & Wild (2010, Cat. J/MNRAS/405/2302). The absorption system redshift (zabs), system grade, and detected lines are outputs of the York et al. (2013, in. prep.) QAL detection pipeline. Some absorption lines are flagged based on alternate identifications (a), proximity of masked pixels (b), or questionable continuum fits (c). (3 data files).

  3. Absorption lines in the spectrum of Q0248 + 4302 due to a foreground tidal tail

    SciTech Connect

    Sargent, W.L.W.; Steidel, C.C. California Univ., Berkeley )

    1990-08-01

    The strong absorption lines in the spectrum of the quasar Q0248 + 4302 are discussed. The absorption has been shown to be produced in a sinuous tidal tail which emanates from the nearby galaxy pair G0248 + 4302A,B. There is a velocity difference of about 260 km/s between the systemic redshift of the interacting galaxies and the redshift of the tidal tail at a galactocentric distance of about 11/h kpc. The large velocity spread observed in the tail gas is probably responsible for the unusual strength of the interstellar lines. 18 refs.

  4. Rest-frame optical properties of luminous, radio-selected broad absorption line quasars

    NASA Astrophysics Data System (ADS)

    Runnoe, Jessie C.; Ganguly, R.; Brotherton, M. S.; DiPompeo, M. A.

    2013-08-01

    We have obtained Infrared Telescope Facility/SpeX spectra of eight moderate-redshift (z = 0.7-2.4), radio-selected (log R* ≈ 0.4-1.9) broad absorption line (BAL) quasars. The spectra cover the rest-frame optical band. We compare the optical properties of these quasars to those of canonically radio-quiet (log R* ≲ 1) BAL quasars at similar redshifts and to low-redshift quasars from the Palomar-Green catalogue. As with previous studies of BAL quasars, we find that [O III] λ5007 is weak, and optical Fe II emission is strong, a rare combination in canonically radio-loud (log R* ≳ 1) quasars. With our measurements of the optical properties, particularly the Balmer emission-line widths and the continuum luminosity, we have used empirical scaling relations to estimate black hole masses and Eddington ratios. These lie in the range (0.4-2.6) × 109 M⊙ and 0.1-0.9, respectively. Despite their comparatively extreme radio properties relative to most BAL quasars, their optical properties are quite consistent with those of radio-quiet BAL quasars and dissimilar to those of radio-loud non-BAL quasars. While BAL quasars generally appear to have low values of [O III] λ5007/Fe II an extreme of `Eigenvector 1', the Balmer line widths and Eddington ratios do not appear to significantly differ from those of unabsorbed quasars at similar redshifts and luminosities.

  5. X-ray absorption/emission line spectroscopy of the Galactic hot gaseous halo

    NASA Astrophysics Data System (ADS)

    Wang, Daniel

    2016-04-01

    There is an ongoing debate as to whether or not the Milky Way is surrounded by a large-scale, massive corona. Vastly different conclusions as to its extent and mass have been drawn from existing studies based on X-ray absorption and/or emission line spectroscopy. I will discuss my assessment of this issue, focusing on various uncertainties and potential problems in the present data, analyses, results, and interpretations.In particular, I will examine how different assumptions about the temperature distribution of the corona affect the inference of its physical scale. I will also discuss the external perspectives of galactic coronae obtained form observing nearby highly-inclined disk galaxies.

  6. Gamma–Gamma Absorption in the Broad Line Region Radiation Fields of Gamma-Ray Blazars

    NASA Astrophysics Data System (ADS)

    Böttcher, Markus; Els, Paul

    2016-04-01

    The expected level of γγ absorption in the Broad Line Region (BLR) radiation field of γ-ray loud Flat Spectrum Radio Quasars (FSRQs) is evaluated as a function of the location of the γ-ray emission region. This is done self-consistently with parameters inferred from the shape of the spectral energy distribution (SED) in a single-zone leptonic EC-BLR model scenario. We take into account all geometrical effects both in the calculation of the γγ opacity and the normalization of the BLR radiation energy density. As specific examples, we study the FSRQs 3C279 and PKS 1510-089, keeping the BLR radiation energy density at the location of the emission region fixed at the values inferred from the SED. We confirm previous findings that the optical depth due to γγ absorption in the BLR radiation field exceeds unity for both 3C279 and PKS 1510-089 for locations of the γ-ray emission region inside the inner boundary of the BLR. It decreases monotonically, with distance from the central engine and drops below unity for locations within the BLR. For locations outside the BLR, the BLR radiation energy density required for the production of GeV γ-rays rapidly increases beyond observational constraints, thus making the EC-BLR mechanism implausible. Therefore, in order to avoid significant γγ absorption by the BLR radiation field, the γ-ray emission region must therefore be located near the outer boundary of the BLR.

  7. Quasars as the formation sites of high-redshift ellipticals: a signature in the `associated' absorption-line systems?

    NASA Astrophysics Data System (ADS)

    Franceschini, A.; Gratton, R.

    1997-03-01

    Published data on the average metallicities and abundance ratios for absorption-line systems in high-redshift quasars suggest that a dichotomy may exist between the chemical composition of damped Lyman alpha (Lyalpha) systems (interpreted as intervening galaxies in the QSO line of sight) and the z_abs~=z_em absorption- line systems associated with the quasar. Intervening systems have smaller than solar metallicities, whereas associated absorbers have solar or greater than solar metallicities and small N/C ratios. While these results have to be confirmed by more precise abundance determinations, we argue that they may be explained by an early phase of efficient metal enrichment occurring only in the close environment of high-z QSOs, and characterized by an excess type-II supernova (SNII) activity. This is reminiscent of the SNII phase required to explain the abundance ratios (favouring alpha- over Fe-group elements) observed in the intracluster (IC) medium of local galaxy clusters. We explore the following scenario, to be tested by forthcoming observations of QSO absorption lines using very large optical telescopes. (a) Well-studied damped- Lyalpha, Lyalpha and metal lines in intervening systems trace only part of the history of metal production in the Universe - the one concerning slowly star-forming discs or dwarf irregulars. (b) The complementary class of early-type and bulge-dominated galaxies formed quickly (at z>~4-5) through a huge episode of star formation favouring high-mass stars. (c) The nucleus of the latter is the site of the subsequent formation of a quasar, which partly hides from view the dimmer host galaxy. (d) The products of a galactic wind, following the violent episode of star formation in the host galaxy and metal pollution of the IC medium in the forming cluster, could be directly observable in the z_abs~=z_em associated absorption systems on the QSO line of sight.

  8. Cross section calculations of astrophysical interest. [for theories of absorption and emission lines

    NASA Technical Reports Server (NTRS)

    Gerjuoy, E.

    1974-01-01

    Cross sections are discussed for rotational excitation associated with theories of absorption and emission lines from molecules in space with emphasis on H2CO, CO, and OH by collisions with neutral particles such H, H2, and He. The sensitivity of the Thaddeus equation for the H2CO calculation is examined.

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

    SciTech Connect

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

    2012-10-01

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

  10. A summary of transition probabilities for atomic absorption lines formed in low-density clouds

    NASA Technical Reports Server (NTRS)

    Morton, D. C.; Smith, W. H.

    1973-01-01

    A table of wavelengths, statistical weights, and excitation energies is given for 944 atomic spectral lines in 221 multiplets whose lower energy levels lie below 0.275 eV. Oscillator strengths were adopted for 635 lines in 155 multiplets from the available experimental and theoretical determinations. Radiation damping constants also were derived for most of these lines. This table contains the lines most likely to be observed in absorption in interstellar clouds, circumstellar shells, and the clouds in the direction of quasars where neither the particle density nor the radiation density is high enough to populate the higher levels. All ions of all elements from hydrogen to zinc are included which have resonance lines longward of 912 A, although a number of weaker lines of neutrals and first ions have been omitted.

  11. A new perspective on the interstellar cloud surrounding the Sun from UV absorption line results

    NASA Astrophysics Data System (ADS)

    Gry, Cecile; Jenkins, Edward B.

    2015-01-01

    We offer a new, more inclusive, picture of the local interstellar medium, where it is composed of a single, monolithic cloud that surrounds the Sun in all directions. Our study of velocities based on Mg II and Fe II ultraviolet absorption lines indicates that the cloud has an average motion consistent with the velocity vector of gas impacting the heliosphere and does not behave like a rigid body: gas within the cloud is being differentially decelerated in the direction of motion, and the cloud is expanding in directions perpendicular to this flow, much like the squashing of a balloon. The outer boundary of the cloud is in average 10 pc away from us but is highly irregular, being only a few parsecs away in some directions, with possibly a few extensions up to 20 pc. Average H I volume densities vary between 0.03 and 0.1 cm3 over different sight lines. Metals appear to be significantly depleted onto grains, and there is a steady increase in this effect from the rear of the cloud to the apex of motion. There is no evidence that changes in the ionizing radiation influence the apparent abundances. Additional, secondary velocity components are detected in 60% of the sight lines. Almost all of them appear to be interior to the volume holding the gas that we identify with the main cloud. Half of the sight lines exhibit a secondary component moving at about - 7.2 km/s with respect to the main component, which may be the signature of an implosive shock propagating toward the cloud's interior.

  12. Atlas of absorption lines from 0 to 17 900 cm(-1)

    NASA Technical Reports Server (NTRS)

    Park, J. H.; Rothman, L. S.; Rinsland, C. P.; Smith, M. A. H.; Richardson, D. J.; Larsen, J. C.

    1981-01-01

    Plots of absorption line strength versus line position for wavenumbers from 0 to 17,900 cm(-1) are shown for 20 atmospheric gases (H2O, CO2, O3, N2O, CO, CH4, O2, NO, SO2, NO2, NH3, HNO3, OH, HF, HCl, HBr, HI, ClO, OCS, H2CO). Also shown are similar plots of lower-state energy values for adsorption lines for the strongly adsorbing atmospheric gases (H2O, CO2, O3, and CH4) for wavenumbers from 0 to 5000 cm(-1).

  13. Absorption line profiles in a companion spectrum of a mass losing cool supergiant

    NASA Technical Reports Server (NTRS)

    Rodrigues, Liliya L.; Boehm-Vitense, Erika

    1990-01-01

    Cool star winds can best be observed in resonance absorption lines seen in the spectrum of a hot companion, due to the wind passing in front of the blue star. We calculated absorption line profiles that would be seen in the ultraviolet part of the blue companion spectrum. Line profiles are derived for different radial dependences of the cool star wind and for different orbital phases of the binary. Bowen and Wilson find theoretically that stellar pulsations drive mass loss. We therefore apply our calculations to the Cepheid binary S Muscae which has a B5V companion. We find an upper limit for the Cepheid mass loss of M less than or equal to 7 x 10(exp -10) solar mass per year provided that the stellar wind of the companion does not influence the Cepheid wind at large distances.

  14. Absorption-line profiles in a companion spectrum of a mass-losing cool supergiant

    NASA Technical Reports Server (NTRS)

    Rodrigues, Liliya L.; Boehm-Vitense, Erika

    1992-01-01

    Cool star winds can best be observed in resonance absorption lines seen in the spectrum of a hot companion, due to the wind passing in front of the blue star. We calculated absorption line profiles that would be seen in the ultraviolet part of the blue companion spectrum. Line profiles are derived for different radial dependences of the cool star wind and for different orbital phases of the binary. Bowen and Wilson find theoretically that stellar pulsations drive mass loss. We therefore apply our calculations to the Cepheid binary S Muscae which has a B5V companion. We find an upper limit for the Cepheid mass loss of M less than or equal to 7 x 10 (exp -10) solar mass per year provided that the stellar wind of the companion does not influence the Cepheid wind at large distances.

  15. Relative f-values from interstellar absorption lines: advantages and pitfalls

    NASA Astrophysics Data System (ADS)

    Jenkins, Edward B.

    2009-05-01

    Interstellar absorption features seen in the ultraviolet and visible spectra of stars provide opportunities for comparing the strengths of different transitions out of the ground electronic states of atoms, ions and simple molecules. In principle, such measurements are straightforward since the radiative transfer is manifested as a simple exponential absorption law at any given radial velocity. Complications arise when the velocity structures of the lines are not completely resolved, or when the lines are either very strongly saturated or too weak to observe. Dynamic range limitations can compromise the comparisons of two transitions that have very different absorption f-values, but they can be mitigated if there are examples with very different column densities and transitions of intermediate strength that can help to bridge the large gap in line strengths. Attempts to unravel the effects of saturation include the use of a curve of growth when only equivalent widths are available, or the measurements of the 'apparent optical depth' when the line is mostly resolved by the instrument. Unfortunately, the application of the curve of growth for one constituent to that of another can sometimes create systematic errors, since the two may have different velocity structures. Likewise, unresolved fine velocity structures in features that have large optical depths can make the apparent optical depths misrepresent the smoothed versions of the true optical depths. One method to compare the strength of a very weak line to that of a very strong one is to measure the total absorption of the former and compare it with the strength of the damping wings of the latter. However in many circumstances, small amounts of gas at velocities well displaced from the line center can masquerade as damping wings. For this reason, it is important to check that these wings have the proper shape.

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

    SciTech Connect

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

    2012-10-01

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

  17. AN INFRARED EXCESS IDENTIFIED IN RADIO-LOUD BROAD ABSORPTION LINE QUASARS

    SciTech Connect

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

    2013-01-10

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

  18. Magnetic Turbulence and Line Broadening in Simulations of Lyman-Alpha Absorption

    NASA Astrophysics Data System (ADS)

    Gurvich, Alex; Burkhart, Blakesley K.; Bird, Simeon

    2016-01-01

    We use the Illustris cosmological AREPO simulations to study the effects of gas turbulence and magnetic fields on measurements from the Lyman-Alpha forest. We generate simulated Lyman-Alpha spectra and plot the distributions of Column Density (CDD) and Doppler Width (b) both by adhering to the canonical method of fitting Voigt profiles to absorption lines and by directly measuring the column density and equivalent widths from snapshot data .We investigate the effects of additional unresolved gas turbulence in Illustris by adding an additional broadening term to the line profiles to mimic turbulent broadening. When we do this, we find a measurable effect in the CDD and an offset in the mean of the b distribution corresponding to the additional turbulence. We also compare different MHD runs in AREPO we find that the CDD can measurably differentiate between magnetic seed field at redshifts as low as z=0.1, but we do not find that the b distribution is affected at a detectable level. Our work suggests that the effects of turbulence and magnetic fields from z=2-0.1 can potentially be measured with these diagnostics. This work was supported in part by the NSF REU and DoD ASSURE programs under NSF grant no. 1262851 and by the Smithsonian Institution.

  19. Time variations of narrow absorption lines in high resolution quasar spectra

    NASA Astrophysics Data System (ADS)

    Boissé, P.; Bergeron, J.; Prochaska, J. X.; Péroux, C.; York, D. G.

    2015-09-01

    Aims: We have searched for temporal variations of narrow absorption lines in high resolution quasar spectra. A sample of five distant sources were assembled, for which two spectra are available, either VLT/UVES or Keck/HIRES, which were taken several years apart. Methods: We first investigate under which conditions variations in absorption line profiles can be detected reliably from high resolution spectra and discuss the implications of changes in terms of small-scale structure within the intervening gas or intrinsic origin. The targets selected allow us to investigate the time behaviour of a broad variety of absorption line systems by sampling diverse environments: the vicinity of active nuclei, galaxy halos, molecular-rich galaxy disks associated with damped Lyα systems, as well as neutral gas within our own Galaxy. Results: Intervening absorption lines from Mg ii, Fe ii, or proxy species with lines of lower opacity tracing the same kind of (moderately ionised) gas appear in general to be remarkably stable (1σ upper limits as low as 10% for some components on scales in the range 10-100 au), even for systems at zabs ≈ ze. Marginal variations are observed for Mg ii lines towards PKS 1229-021 at zabs = 0.83032; however, we detect no systems that display any change as large as those reported in low resolution SDSS spectra. The lack of clear variations for low β Mg ii systems does not support the existence of a specific population of absorbers made of swept-up gas towards blazars. In neutral or diffuse molecular media, clear changes are seen for Galactic Na i lines towards PKS 1229-02 (decrease in N by a factor of four for one of the five components over 9.7 yr), corresponding to structure on a scale of about 35 au, in good agreement with known properties of the Galactic interstellar medium. Tentative variations are detected for H2J = 3 lines towards FBQS J2340-0053 at zabs = 2.05454 (≃35% change in column density, N, over 0.7 yr in the rest frame), suggesting

  20. LOW-z Mg II BROAD ABSORPTION-LINE QUASARS FROM THE SLOAN DIGITAL SKY SURVEY

    SciTech Connect

    Zhang Shaohua; Wang Tingi; Wang Huiyuan; Zhou Hongyan; Dong Xiaobo; Wang Jianguo E-mail: whywang@mail.ustc.edu.c

    2010-05-01

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

  1. THE PHYSICAL CONDITIONS OF THE INTRINSIC N V NARROW ABSORPTION LINE SYSTEMS OF THREE QUASARS

    SciTech Connect

    Wu Jian; Charlton, Jane C.; Misawa, Toru; Eracleous, Michael; Ganguly, Rajib E-mail: misawatr@shinshu-u.ac.j

    2010-10-20

    We employ detailed photoionization models to infer the physical conditions of intrinsic narrow absorption line systems found in high-resolution spectra of three quasars at z = 2.6-3.0. We focus on a family of intrinsic absorbers characterized by N V lines that are strong relative to the Ly{alpha} lines. The inferred physical conditions are similar for the three intrinsic N V absorbers, with metallicities greater than 10 times the solar value (assuming a solar abundance pattern), and with high ionization parameters (log U {approx} 0). Thus, we conclude that the unusual strength of the N V lines results from a combination of partial coverage, a high ionization state, and high metallicity. We consider whether dilution of the absorption lines by flux from the broad emission line region can lead us to overestimate the metallicities and we find that this is an unlikely possibility. The high abundances that we infer are not surprising in the context of scenarios in which metal enrichment takes place very early on in massive galaxies. We estimate that the mass outflow rate in the absorbing gas (which is likely to have a filamentary structure) is less than a few M{sub sun} yr{sup -1} under the most optimistic assumptions, although it may be embedded in a much hotter, more massive outflow.

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

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  3. Reionisation and High-Redshift Galaxies: The View from Quasar Absorption Lines

    NASA Astrophysics Data System (ADS)

    Becker, George D.; Bolton, James S.; Lidz, Adam

    2015-12-01

    Determining when and how the first galaxies reionised the intergalactic medium promises to shed light on both the nature of the first objects and the cosmic history of baryons. Towards this goal, quasar absorption lines play a unique role by probing the properties of diffuse gas on galactic and intergalactic scales. In this review, we examine the multiple ways in which absorption lines trace the connection between galaxies and the intergalactic medium near the reionisation epoch. We first describe how the Ly α forest is used to determine the intensity of the ionising ultraviolet background and the global ionising emissivity budget. Critically, these measurements reflect the escaping ionising radiation from all galaxies, including those too faint to detect directly. We then discuss insights from metal absorption lines into reionisation-era galaxies and their surroundings. Current observations suggest a buildup of metals in the circumgalactic environments of galaxies over z ~ 6 to 5, although changes in ionisation will also affect the evolution of metal line properties. A substantial fraction of metal absorbers at these redshifts may trace relatively low-mass galaxies. Finally, we review constraints from the Ly α forest and quasar near zones on the timing of reionisation. Along with other probes of the high-redshift Universe, absorption line data are consistent with a relatively late end to reionisation (5.5 ≲ z ≲ 7); however, the constraints are still fairly week. Significant progress is expected to come through improved analysis techniques, increases in the number of known high-redshift quasars from optical and infrared sky surveys, large gains in sensitivity from next-generation observing facilities, and synergies with other probes of the reionisation era.

  4. The Hubble Space Telescope quasar absorption line key project. III - First observational results on Milky Way gas

    NASA Technical Reports Server (NTRS)

    Savage, Blair D.; Lu, Limin; Bahcall, John N.; Bergeron, Jacqueline; Boksenberg, Alec; Hartig, George F.; Jannuzi, Buell T.; Kirhakos, Sofia; Lockman, Felix J.; Sargent, W. L. W.

    1993-01-01

    Absorption lines found near zero redshift due to Milky Way disk and halo gas in the spectra of 15 quasars observed with the Faint Object Spectrograph (FOS) of the HST at a resolution of about 230 km/s are reported. Results show that Milky Way absorption lines comprise about 44 percent of all absorption lines seen in the first group of Key Project FOS spectra. Milky Way lines were observed for 3C 273 and H1821 + 643. Limits to the Mg-to-H abundance ratio obtained for very high velocity Mg II absorption detections imply gas-phase Mg abundances for the very high velocity gas ranging from more than 0.059 to more than 0.32 times the solar abundance. In all cases where high-velocity H I emission is seen, corresponding high-velocity metal-line absorption is observed.

  5. Reconstruction of combustion temperature and gas concentration distributions using line-of-sight tunable diode laser absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Zhirong; Sun, Pengshuai; Pang, Tao; Xia, Hua; Cui, Xiaojuan; Li, Zhe; Han, Luo; Wu, Bian; Wang, Yu; Sigrist, Markus W.; Dong, Fengzhong

    2016-07-01

    Spatial temperature and gas concentration distributions are crucial for combustion studies to characterize the combustion position and to evaluate the combustion regime and the released heat quantity. Optical computer tomography (CT) enables the reconstruction of temperature and gas concentration fields in a flame on the basis of line-of-sight tunable diode laser absorption spectroscopy (LOS-TDLAS). A pair of H2O absorption lines at wavelengths 1395.51 and 1395.69 nm is selected. Temperature and H2O concentration distributions for a flat flame furnace are calculated by superimposing two absorption peaks with a discrete algebraic iterative algorithm and a mathematical fitting algorithm. By comparison, direct absorption spectroscopy measurements agree well with the thermocouple measurements and yield a good correlation. The CT reconstruction data of different air-to-fuel ratio combustion conditions (incomplete combustion and full combustion) and three different types of burners (one, two, and three flat flame furnaces) demonstrate that TDLAS has the potential of short response time and enables real-time temperature and gas concentration distribution measurements for combustion diagnosis.

  6. Reconstruction of combustion temperature and gas concentration distributions using line-of-sight tunable diode laser absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Zhirong; Sun, Pengshuai; Pang, Tao; Xia, Hua; Cui, Xiaojuan; Li, Zhe; Han, Luo; Wu, Bian; Wang, Yu; Sigrist, Markus W.; Dong, Fengzhong

    2016-07-01

    Spatial temperature and gas concentration distributions are crucial for combustion studies to characterize the combustion position and to evaluate the combustion regime and the released heat quantity. Optical computer tomography (CT) enables the reconstruction of temperature and gas concentration fields in a flame on the basis of line-of-sight tunable diode laser absorption spectroscopy (LOS-TDLAS). A pair of H2O absorption lines at wavelengths 1395.51 and 1395.69 nm is selected. Temperature and H2O concentration distributions for a flat flame furnace are calculated by superimposing two absorption peaks with a discrete algebraic iterative algorithm and a mathematical fitting algorithm. By comparison, direct absorption spectroscopy measurements agree well with the thermocouple measurements and yield a good correlation. The CT reconstruction data of different air-to-fuel ratio combustion conditions (incomplete combustion and full combustion) and three different types of burners (one, two, and three flat flame furnaces) demonstrate that TDLAS has the potential of short response time and enables real-time temperature and gas concentration distribution measurements for combustion diagnosis.

  7. The Hubble Space Telescope Quasar Absorption Line Key Project. XIV. The Evolution of Lyα Absorption Lines in the Redshift Interval z = 0-1.5

    NASA Astrophysics Data System (ADS)

    Weymann, Ray J.; Jannuzi, Buell T.; Lu, Limin; Bahcall, John N.; Bergeron, Jacqueline; Boksenberg, Alec; Hartig, George F.; Kirhakos, Sofia; Sargent, W. L. W.; Savage, Blair D.; Schneider, Donald P.; Turnshek, David A.; Wolfe, Arthur M.

    1998-10-01

    We present the results of an analysis of the rate of evolution of the Lyα absorption lines in the redshift interval 0.0 to ~1.5 based upon a sample of 987 Lyα absorption lines identified in the spectra of 63 QSOs obtained with the Faint Object Spectrograph (FOS) of the Hubble Space Telescope (HST). These spectra were obtained as part of the QSO Absorption Line Survey, an HST Key Project during the first four years of observations with the telescope. Fits to the evolution of the number of absorbers per unit redshift (dN/dz) of the form dN/dz = A × (1 + z)γ continue to yield values of γ in the range 0.1-0.3, decidedly flatter than results from ground-based data pertaining to the redshift range z > 1.7. These results are consistent with our previous results based on a much smaller sample of lines, but the uncertainties in the fit have been greatly reduced. The combination of the HST and ground-based data suggest a marked transition in the rate of evolution of the Lyα lines at a redshift of about 1.7. The 19 Lyα lines from an additional higher redshift QSO from our sample for which tentative line identifications are available (UM 18; zem = 1.89) support the suggestion of a rapid increase at around this redshift. We derive the cumulative distribution of the full sample of Lyα lines and show that the distribution in redshift can indeed be well represented by a power law of the form (1 + z)γ. For this same sample, the distribution of equivalent widths of the Lyα absorbers above a rest equivalent width of 0.1 Å is fit quite well by an exponential. Comparing samples of Lyα lines, one set of which has redshifts the same as, or very near to, the redshifts of ions from heavy elements and another set in which no ions from heavy elements have been identified, we find that the Lyα systems with heavy element detections have a much steeper slope than the high rest equivalent width portion of the Lyman-only sample. We argue that this result is not likely to be due to

  8. Broad absorption line variability on multi-year timescales in a large quasar sample

    NASA Astrophysics Data System (ADS)

    Filiz Ak, Nurten

    Outflows launched near the central supermassive black holes (SMBHs) are a common and important component of active galactic nuclei (AGNs). Outflows in luminous AGNs (i.e., quasars) play a key role in mass accretion onto SMBH as well as in the feedback into host galaxies. The most prominent signature of such outflows appears as broad absorption lines (BALs) that are blueshifted from the emission line with a few thousands km s--1 velocities. In this dissertation, I place further constrains upon the size scale, internal structure, dynamics, and evolution of the outflows investigating profiles, properties, and variation characteristics of BAL troughs. I present observational results on BAL troughs in a large quasar sample utilizing spectroscopic observations from the Sloan Digital Sky Survey spanning on multi-year timescales. The results presented here, for the first time, provide a large and well-defined variability data base capable of discriminating between time-dependent hydrodynamic wind calculations in a statistically powerful manner. In a study of 582 quasars, I present 21 examples of BAL trough disappearance. Approximately 3.3% of BAL quasars show disappearing C IV trough on rest-frame timescales of 1.1--3.9 yr. BAL disappearance appears to occur mainly for shallow and weak or moderate-strength absorption troughs but not the strongest ones. When one BAL trough in a quasar spectrum disappears, the other present troughs usually weaken. Possible causes of such coordinated variations could be disk-wind rotation or variations of shielding gas that lead to variations of ionizing-continuum radiation. I present a detailed study on the variability of 428 C IV and 235 Si IV BAL troughs using a systematically observed sample of 291 BAL quasars. BAL variation distributions indicate that BAL disappearance is an extreme type of general BAL variability, rather than a qualitatively distinct phenomenon. The high observed frequency of BAL variability on multi-year timescales is

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  10. Protonation effects on the UV/Vis absorption spectra of imatinib: A theoretical and experimental study

    NASA Astrophysics Data System (ADS)

    Grante, Ilze; Actins, Andris; Orola, Liana

    2014-08-01

    An experimental and theoretical investigation of protonation effects on the UV/Vis absorption spectra of imatinib showed systematic changes of absorption depending on the pH, and a new absorption band appeared below pH 2. These changes in the UV/Vis absorption spectra were interpreted using quantum chemical calculations. The geometry of various imatinib cations in the gas phase and in ethanol solution was optimized with the DFT/B3LYP method. The resultant geometries were compared to the experimentally determined crystal structures of imatinib salts. The semi-empirical ZINDO-CI method was employed to calculate the absorption lines and electronic transitions. Our study suggests that the formation of the extra near-UV absorption band resulted from an increase of imatinib trication concentration in the solution, while the rapid increase of the first absorption maximum could be attributed to both the formation of imatinib trication and tetracation.

  11. The VLBI structure of radio-loud Broad Absorption Line quasars

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Jiang, D. R.; Gu, M.

    2016-02-01

    The nature and origin of Broad Absorption Line (BAL) quasars and their relationship to non-BAL quasars are an open question. The BAL quasars are probably normal quasars seen along a particular line of sight. Alternatively, they are young or recently refueled. The high resolution radio morphology of BAL quasars is very important to understand the radio properties of BAL quasars. We present VLBA observations at L and C bands for a sample of BAL quasars. The observations will help us to explore the VLBI radio properties, and distinguish the present models of explaining BAL phenomena.

  12. The spatial and kinematic structure of QSO metal-line absorption systems

    NASA Technical Reports Server (NTRS)

    Lanzetta, Kenneth M.

    1992-01-01

    Recent attempts to infer the spatial and kinematic distributions of the material responsible for absorption lines observed in the spectra of background QSOs are presented. Current models of the absorbing regions are compared, and initial observational results are described. This research is expected to lead eventually to a detailed picture of the extended gaseous halo regions of galaxies at early evolutionary stages and to an understanding of the physical processes at work in these halos.

  13. 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.

  14. Wavelength Locking to CO2 Absorption Line-Center for 2-Micron Pulsed IPDA Lidar Application

    NASA Technical Reports Server (NTRS)

    Refaat, Tamer F.; Petros, Mulugeta; Antill, Charles W.; Singh, Upendra N.; Yu, Jirong

    2016-01-01

    An airborne 2-micron triple-pulse integrated path differential absorption (IPDA) lidar is currently under development at NASA Langley Research Center (LaRC). This IPDA lidar system targets both atmospheric carbon dioxide (CO2) and water vapor (H2O) column measurements. Independent wavelength control of each of the transmitted laser pulses is a key feature for the success of this instrument. The wavelength control unit provides switching, tuning and locking for each pulse in reference to a 2-micron CW (Continuous Wave) laser source locked to CO2 line-center. Targeting the CO2 R30 line center, at 2050.967 nanometers, a wavelength locking unit has been integrated using semiconductor laser diode. The CO2 center-line locking unit includes a laser diode current driver, temperature controller, center-line locking controller and CO2 absorption cell. This paper presents the CO2 center-line locking unit architecture, characterization procedure and results. Assessment of wavelength jitter on the IPDA measurement error will also be addressed by comparison to the system design.

  15. Observations of absorption lines from highly ionized atoms. [of interstellar medium

    NASA Technical Reports Server (NTRS)

    Jenkins, Edward B.

    1987-01-01

    In the ultraviolet spectra of hot stars, absorption lines can be seen from highly ionized species in the interstellar medium. Observations of these features which have been very influential in revising the perception of the medium's various physical states, are discussed. The pervasiveness of O 6 absorption lines, coupled with complementary observations of a diffuse background in soft X-rays and EUV radiation, shows that there is an extensive network of low density gas (n approx. few x 0.001/cu cm) existing at coronal temperatures log T = 5.3 or 6.3. Shocks created by supernova explosions or mass loss from early-type stars can propagate freely through space and eventually transfer a large amount of energy to the medium. To create the coronal temperatures, the shocks must have velocities in excess of 150 km/sec; shocks at somewhat lower velocity (v = 100 km/sec) can be directly observed in the lines of Si3. Observations of other lines in the ultraviolet, such as Si 4V and C 5, may highlight the widespread presence of energetic UV radiation from very hot, dwarf stars. More advanced techniques in visible and X-ray astronomical spectroscopy may open up for inspection selected lines from atoms in much higher stages of ionization.

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  17. Measurability of Kinetic Temperature from Metal Absorption-Line Spectra Formed in Chaotic Media

    NASA Astrophysics Data System (ADS)

    Levshakov, Sergei A.; Takahara, Fumio; Agafonova, Irina I.

    1999-06-01

    We present a new method for recovering the kinetic temperature of the intervening diffuse gas to an accuracy of 10%. The method is based on the comparison of unsaturated absorption-line profiles of two species with different atomic weights. The species are assumed to have the same temperature and bulk motion within the absorbing region. The computational technique involves the Fourier transform of the absorption profiles and the consequent entropy-regularized χ2-minimization (ERM) to estimate the model parameters. The procedure is tested using synthetic spectra of C+, Si+, and Fe+ ions. The comparison with the standard Voigt fitting analysis is performed, and it is shown that the Voigt deconvolution of the complex absorption-line profiles may result in estimated temperatures that are not physical. We also successfully analyze Keck telescope spectra of C II λ1334 and Si II λ1260 lines observed at the redshift z=3.572 toward the quasar Q1937-1009 by Tytler et al. Based in part on data obtained at the W. M. Keck Observatory, which is jointly operated by the University of California and the California Institute of Technology.

  18. A new analysis of fine-structure constant measurements and modelling errors from quasar absorption lines

    NASA Astrophysics Data System (ADS)

    Wilczynska, Michael R.; Webb, John K.; King, Julian A.; Murphy, Michael T.; Bainbridge, Matthew B.; Flambaum, Victor V.

    2015-12-01

    We present an analysis of 23 absorption systems along the lines of sight towards 18 quasars in the redshift range of 0.4 ≤ zabs ≤ 2.3 observed on the Very Large Telescope (VLT) using the Ultraviolet and Visual Echelle Spectrograph (UVES). Considering both statistical and systematic error contributions we find a robust estimate of the weighted mean deviation of the fine-structure constant from its current, laboratory value of Δα/α = (0.22 ± 0.23) × 10-5, consistent with the dipole variation reported in Webb et al. and King et al. This paper also examines modelling methodologies and systematic effects. In particular, we focus on the consequences of fitting quasar absorption systems with too few absorbing components and of selectively fitting only the stronger components in an absorption complex. We show that using insufficient continuum regions around an absorption complex causes a significant increase in the scatter of a sample of Δα/α measurements, thus unnecessarily reducing the overall precision. We further show that fitting absorption systems with too few velocity components also results in a significant increase in the scatter of Δα/α measurements, and in addition causes Δα/α error estimates to be systematically underestimated. These results thus identify some of the potential pitfalls in analysis techniques and provide a guide for future analyses.

  19. Beyond the single-atom response in absorption line shapes: probing a dense, laser-dressed helium gas with attosecond pulse trains.

    PubMed

    Liao, Chen-Ting; Sandhu, Arvinder; Camp, Seth; Schafer, Kenneth J; Gaarde, Mette B

    2015-04-10

    We investigate the absorption line shapes of laser-dressed atoms beyond the single-atom response, by using extreme ultraviolet (XUV) attosecond pulse trains to probe an optically thick helium target under the influence of a strong infrared (IR) field. We study the interplay between the IR-induced phase shift of the microscopic time-dependent dipole moment and the resonant-propagation-induced reshaping of the macroscopic XUV pulse. Our experimental and theoretical results show that as the optical depth increases, this interplay leads initially to a broadening of the IR-modified line shape, and subsequently, to the appearance of new, narrow features in the absorption line.

  20. Beyond the single-atom response in absorption line shapes: probing a dense, laser-dressed helium gas with attosecond pulse trains.

    PubMed

    Liao, Chen-Ting; Sandhu, Arvinder; Camp, Seth; Schafer, Kenneth J; Gaarde, Mette B

    2015-04-10

    We investigate the absorption line shapes of laser-dressed atoms beyond the single-atom response, by using extreme ultraviolet (XUV) attosecond pulse trains to probe an optically thick helium target under the influence of a strong infrared (IR) field. We study the interplay between the IR-induced phase shift of the microscopic time-dependent dipole moment and the resonant-propagation-induced reshaping of the macroscopic XUV pulse. Our experimental and theoretical results show that as the optical depth increases, this interplay leads initially to a broadening of the IR-modified line shape, and subsequently, to the appearance of new, narrow features in the absorption line. PMID:25910116

  1. Constraining the variation of the fine-structure constant with observations of narrow quasar absorption lines

    SciTech Connect

    Songaila, A.; Cowie, L. L.

    2014-10-01

    The unequivocal demonstration of temporal or spatial variability in a fundamental constant of nature would be of enormous significance. Recent attempts to measure the variability of the fine-structure constant α over cosmological time, using high-resolution spectra of high-redshift quasars observed with 10 m class telescopes, have produced conflicting results. We use the many multiplet (MM) method with Mg II and Fe II lines on very high signal-to-noise, high-resolution (R = 72, 000) Keck HIRES spectra of eight narrow quasar absorption systems. We consider both systematic uncertainties in spectrograph wavelength calibration and also velocity offsets introduced by complex velocity structure in even apparently simple and weak narrow lines and analyze their effect on claimed variations in α. We find no significant change in α, Δα/α = (0.43 ± 0.34) × 10{sup –5}, in the redshift range z = 0.7-1.5, where this includes both statistical and systematic errors. We also show that the scatter in measurements of Δα/α arising from absorption line structure can be considerably larger than assigned statistical errors even for apparently simple and narrow absorption systems. We find a null result of Δα/α = (– 0.59 ± 0.55) × 10{sup –5} in a system at z = 1.7382 using lines of Cr II, Zn II, and Mn II, whereas using Cr II and Zn II lines in a system at z = 1.6614 we find a systematic velocity trend that, if interpreted as a shift in α, would correspond to Δα/α = (1.88 ± 0.47) × 10{sup –5}, where both results include both statistical and systematic errors. This latter result is almost certainly caused by varying ionic abundances in subcomponents of the line: using Mn II, Ni II, and Cr II in the analysis changes the result to Δα/α = (– 0.47 ± 0.53) × 10{sup –5}. Combining the Mg II and Fe II results with estimates based on Mn II, Ni II, and Cr II gives Δα/α = (– 0.01 ± 0.26) × 10{sup –5}. We conclude that spectroscopic measurements of

  2. Metal-line absorption around z ≈ 2.4 star-forming galaxies in the Keck Baryonic Structure Survey

    NASA Astrophysics Data System (ADS)

    Turner, Monica L.; Schaye, Joop; Steidel, Charles C.; Rudie, Gwen C.; Strom, Allison L.

    2014-11-01

    We study metal absorption around 854 z ≈ 2.4 star-forming galaxies taken from the Keck Baryonic Structure Survey. The galaxies examined in this work lie in the fields of 15 hyperluminous background quasi-stellar objects, with galaxy impact parameters ranging from 35 proper kpc (pkpc) to 2 proper Mpc (pMpc). Using the pixel optical depth technique, we present the first galaxy-centred 2D maps of the median absorption by O VI, N V, C IV, C III, and Si IV, as well as updated results for H I. At small galactocentric radii we detect a strong enhancement of the absorption relative to randomly located regions that extend out to at least 180 pkpc in the transverse direction, and ±240 km s-1 along the line of sight (LOS, ˜1 pMpc in the case of pure Hubble flow) for all ions except N V. For C IV (and H I) we detect a significant enhancement of the absorption signal out to 2 pMpc in the transverse direction, corresponding to the maximum impact parameter in our sample. After normalizing the median absorption profiles to account for variations in line strengths and detection limits, in the transverse direction we find no evidence for a sharp drop-off in metals distinct from that of H I. We argue instead that non-detection of some metal-line species in the extended circumgalactic medium is consistent with differences in the detection sensitivity. Along the LOS, the normalized profiles reveal that the enhancement in the absorption is more extended for O VI, C IV, and Si IV than for H I. We also present measurements of the scatter in the pixel optical depths, covering fractions, and equivalent widths as a function of projected galaxy distance. Limiting the sample to the 340 galaxies with redshifts measured from nebular emission lines does not decrease the extent of the enhancement along the LOS compared to that in the transverse direction. This rules out redshift errors as the source of the observed redshift-space anisotropy and thus implies that we have detected the signature

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

    SciTech Connect

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

    2011-12-10

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

  4. THE PITTSBURGH SLOAN DIGITAL SKY SURVEY Mg II QUASAR ABSORPTION-LINE SURVEY CATALOG

    SciTech Connect

    Quider, Anna M.; Nestor, Daniel B.; Turnshek, David A.; Rao, Sandhya M.; Weyant, Anja N.; Monier, Eric M.; Busche, Joseph R.

    2011-04-15

    We present a catalog of intervening Mg II quasar absorption-line systems in the redshift interval 0.36 {<=} z {<=} 2.28. The catalog was built from Sloan Digital Sky Survey Data Release Four (SDSS DR4) quasar spectra. Currently, the catalog contains {approx}17, 000 measured Mg II doublets. We also present data on the {approx}44, 600 quasar spectra which were searched to construct the catalog, including redshift and magnitude information, continuum-normalized spectra, and corresponding arrays of redshift-dependent minimum rest equivalent widths detectable at our confidence threshold. The catalog is available online. A careful second search of 500 random spectra indicated that, for every 100 spectra searched, approximately one significant Mg II system was accidentally rejected. Current plans to expand the catalog beyond DR4 quasars are discussed. Many Mg II absorbers are known to be associated with galaxies. Therefore, the combination of large size and well understood statistics makes this catalog ideal for precision studies of the low-ionization and neutral gas regions associated with galaxies at low to moderate redshift. An analysis of the statistics of Mg II absorbers using this catalog will be presented in a subsequent paper.

  5. An absorption line in the ultraviolet spectrum of 40 Eridani B

    NASA Technical Reports Server (NTRS)

    Greenstein, J. L.

    1980-01-01

    Two excellent low-resolution spectra show an absorption line of equivalent width 3 A, near 1391 A, in the typical DA (hydrogen atmosphere) white dwarf 40 Eri B. The line is confirmed by a high-resolution spectrum and is the first seen in any DA star. Ultraviolet fluxes and the profile of Lyman-alpha confirm an effective temperature near 17,000 K. If the line is Si IV, it requires a temperature near 40,000 K. Unattractive possibilities are a hot circumstellar absorbing envelope dependent on accretion from companions, or formation at large optical depth in a transparent atmosphere with high Si/H. A suggestion that H2 should be considered leads to the possible interpretation as the (0, 5) transition of the Lyman band, formed at small optical depth. The band should be stronger in cooler DAs.

  6. Evidence for active galactic nucleus feedback in the broad absorption lines and reddening of MRK 231 {sup ,}

    SciTech Connect

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

    2014-06-20

    We present the first J-band spectrum of Mrk 231, which reveals a large He I* λ10830 broad absorption line with a profile similar to that of the well-known Na I broad absorption line. Combining this spectrum with optical and UV spectra from the literature, we show that the unusual reddening noted by Veilleux et al. is explained by a reddening curve like those previously used to explain low values of total-to-selective extinction in Type Ia supernovae. The nuclear starburst may be the origin and location of the dust. Spatially resolved emission in the broad absorption line trough suggests nearly full coverage of the continuum emission region. The broad absorption lines reveal higher velocities in the He I* lines (produced in the quasar-photoionized H II region) compared with the Na I and Ca II lines (produced in the corresponding partially ionized zone). Cloudy simulations show that a density increase is required between the H II and partially ionized zones to produce ionic column densities consistent with the optical and IR absorption line measurements and limits, and that the absorber lies ∼100 pc from the central engine. These results suggest that the He I* lines are produced in an ordinary quasar BAL wind that impacts upon, compresses, and accelerates the nuclear starburst's dusty effluent (feedback in action), and the Ca II and Na I lines are produced in this dusty accelerated gas. This unusual circumstance explains the rarity of Na I absorption lines; without the compression along our line of sight, Mrk 231 would appear as an ordinary iron low-ionization, broad absorption line quasar.

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

    NASA Technical Reports Server (NTRS)

    DeKool, Martin; Begelman, Mitchell C.

    1995-01-01

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

  8. Atlas of Absorption Lines from 0 to 17900 Cm (sup)-1

    NASA Technical Reports Server (NTRS)

    Park, J. H.; Rothman, L. S.; Rinsland, C. P.; Pickett, H. M.; Richardson, D. J.; Namkung, J. S.

    1987-01-01

    Plots of logarithm (base 10) of absorption line strength versus wavenumber from 0 to 17900/cm(sup)-1 are shown for the 28 atmospheric gases (H2O, CO2, O3, N2O, CO, CH4, O2, NO, SO2, NO2, NH3, HNO3, OH, HF, HCl, HBr, HI, ClO, OCS, H2CO, HOCl, N2, HCN, CH3Cl, H2O2, C2H2, C2H6, PH3), which appear in the 1986 Air Force Geophysics Laboratory high-resolution transmission molecular absorption data base (HITRAN) compilation, and for O(P-3), O-18 isotopic ozone, and HO2 from the 1984 JPL compilation in the 0- to 200/cm(sup)-1 region, and infrared solar CO lines at 4500 K. Also shown are plots of logarithm (base 10) of approximate infrared absorption cross sections of 11 heavy molecules versus wavenumber. The cross-section data cover 700 to 1800/cm(sup)-1 and are included as a separate data file in the 1986 HITRAN database.

  9. A comparison of neutral hydrogen 21 cm observations with UV and optical absorption-line measurements

    NASA Technical Reports Server (NTRS)

    Giovanelli, R.; York, D. G.; Shull, J. M.; Haynes, M. P.

    1978-01-01

    Several absorption components detected in visible or UV lines have been identified with emission features in new high-resolution, high signal-to-noise 21 cm observations. Stars for which direct overlap is obtained are HD 28497, lambda Ori, mu Col, HD 50896, rho Leo, HD 93521, and HD 219881. With the use of the inferred H I column densities from 21 cm profiles, rather than the integrated column densities obtained from L-alpha, more reliable densities can be derived from the existence of molecular hydrogen. Hence the cloud thicknesses are better determined; and 21 cm emission maps near these stars can be used to obtain dimensions on the plane of the sky. It is now feasible to derive detailed geometries for isolated clumps of gas which produce visual absorption features.

  10. Attosecond transient absorption of argon atoms in the vacuum ultraviolet region: line energy shifts versus coherent population transfer

    NASA Astrophysics Data System (ADS)

    Cao, Wei; Warrick, Erika R.; Neumark, Daniel M.; Leone, Stephen R.

    2016-01-01

    Using attosecond transient absorption, the dipole response of an argon atom in the vacuum ultraviolet (VUV) region is studied when an external electromagnetic field is present. An isolated attosecond VUV pulse populates Rydberg states lying 15 eV above the argon ground state. A synchronized few-cycle near infrared (NIR) pulse modifies the oscillating dipoles of argon impulsively, leading to alterations in the VUV absorption spectra. As the NIR pulse is delayed with respect to the VUV pulse, multiple features in the absorption profile emerge simultaneously including line broadening, sideband structure, sub-cycle fast modulations, and 5-10 fs slow modulations. These features indicate the coexistence of two general processes of the light-matter interaction: the energy shift of individual atomic levels and coherent population transfer between atomic eigenstates, revealing coherent superpositions. An intuitive formula is derived to treat both effects in a unifying framework, allowing one to identify and quantify the two processes in a single absorption spectrogram.

  11. Low redshift Lyman alpha absorption lines and the dark matter halos of disk galaxies

    NASA Technical Reports Server (NTRS)

    Maloney, Philip

    1993-01-01

    Recent observations using the Hubble Space Telescope of the z = 0.156 QSO 3C 273 have discovered a surprisingly large number of Ly-alpha absorption lines. In particular, Morris et al. found 9 certain and 7 possible Ly-alpha lines with equivalent widths above 25 mA. This is much larger (by a factor of 5-10) than the number expected from extrapolation of the high-redshift behavior of the Ly-alpha forest. Within the context of pressure-confined models for the Ly-alpha clouds, this behavior can be understood if the ionizing background declines sharply between z is approximately 2 and z is approximately 0. However, this requires that the ionizing photon flux drop as rapidly as the QSO volume emissivity; moreover, the absorbers must have a space density n(sub O) is approximately 2.6(N/10)h/((D/100 kpc)(sup 2)) Mpc(sup -3) where D is the present-day diameter of the absorbers. It is somewhat surprising that such necessarily fragile objects could have survived in such numbers to the present day. It is shown that it is plausible that the atomic hydrogen extents of spiral and irregular galaxies are large enough to produce the observed number of Ly-alpha absorption lines toward 3C 273, and that the neutral column densities and doppler b-values expected under these conditions fall in the range found by Morris et al. (1991).

  12. Heterodyne detection of the 752.033-GHz H2O rotational absorption line

    NASA Technical Reports Server (NTRS)

    Dionne, G. F.; Fitzgerald, J. F.; Chang, T. S.; Litvak, M. M.; Fetterman, H. R.

    1980-01-01

    A tunable high resolution two stage heterodyne radiometer was developed for the purpose of investigating the intensity and lineshape of the 752.033 GHz rotational transition of water vapor. Single-sideband system noise temperatures of approximately 45,000 K were obtained using a sensitive GaAs Schottky diode as the first stage mixer. First local oscillator power was supplied by a CO2 laser pumped formic acid laser (761.61 GHz), generating an X-band IF signal with theoretical line center at 9.5744 GHz. Second local oscillator power was provided by means of a 3 GHz waveguide cavity filter with only 9 dB insertion loss. In absorption measurements of the H2O taken from a laboratory simulation of a high altitude rocket plume, the center frequency of the 752 GHz line was determined to within 1 MHz of the reported value. A rotational temperature 75 K, a linewidth 5 MHz and a Doppler shift 3 MHz were measured with the line-of-sight intersecting the simulated-plume axis at a distance downstream of 30 nozzle diameters. These absorption data were obtained against continuum background radiation sources at temperatures of 1175 and 300 K.

  13. On the cosmic evolution of Fe/Mg in QSO absorption line systems

    NASA Astrophysics Data System (ADS)

    Dey, Arjun; Torrey, Paul; Rubin, Kate H. R.; Zhu, Guangtun Ben; Suresh, Joshua

    2015-08-01

    We investigate the variation of the ratio of the equivalent widths of the Fe II λ2600 line to the Mg II λλ2796, 2803 doublet as a function of redshift in a large sample of absorption lines drawn from the Johns Hopkins University - Sloan Digital Sky Survey Absorption Line Catalog. We find that despite large scatter, the observed ratio shows a trend where the equivalent width ratio R≡ W_{Fe II}/W_{Mg II} decreases monotonically with increasing redshift z over the range 0.55 ≤ z ≤ 1.90. Selecting the subset of absorbers where the signal-to-noise ratio of the Mg II equivalent width W_{Mg II} is ≥ 3 and modelling the equivalent width ratio distribution as a Gaussian, we find that the mean of the Gaussian distribution varies as R∝ (-0.045± 0.005)z. We discuss various possible reasons for the trend. A monotonic trend in the Fe/Mg abundance ratio is predicted by a simple model where the abundances of Mg and Fe in the absorbing clouds are assumed to be the result of supernova (SN) ejecta and where the cosmic evolution in the SNIa and core-collapse SN rates is related to the cosmic star formation rate. If the trend in R reflects the evolution in the abundances, then it is consistent with the predictions of the simple model.

  14. EXAFS studies of prostate cancer cell lines

    NASA Astrophysics Data System (ADS)

    Czapla, J.; Kwiatek, W. M.; Lekki, J.; Kisiel, A.; Steininger, R.; Goettlicher, J.

    2013-04-01

    Sulphur plays a vital role in every human organism. It is known, that sulphur-bearing compounds, such as for example cysteine and glutathione, play critical roles in development and progression of many diseases. Any alteration in sulphur's biochemistry could become a precursor of serious pathological conditions. One of such condition is prostate cancer, the most frequently diagnosed malignancy in the western world and the second leading cause of cancer related death in men. The purpose of presented studies was to examine what changes occur in the nearest chemical environment of sulphur in prostate cancer cell lines in comparison to healthy cells. The Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy was used, followed by theoretical calculations. The results of preliminary analysis is presented.

  15. Brush border membrane vesicle and Caco-2 cell line: Two experimental models for evaluation of absorption enhancing effects of saponins, bile salts, and some synthetic surfactants

    PubMed Central

    Moghimipour, Eskandar; Tabassi, Sayyed Abolghassem Sajadi; Ramezani, Mohammad; Handali, Somayeh; Löbenberg, Raimar

    2016-01-01

    The aim of this study was to investigate the influence of absorption enhancers in the uptake of hydrophilic compounds. The permeation of the two hydrophilic drug models gentamicin and 5 (6)-carboxyfluorescein (CF) across the brush border membrane vesicles and Caco-2 cell lines were evaluated using total saponins of Acanthophyllum squarrosum, Quillaja saponaria, sodium lauryl sulfate, sodium glycocholate, sodium taurodeoxycholate, and Tween 20 as absorption enhancers. Transepithelial electrical resistance (TEER) measurement was utilized to assess the paracellular permeability of cell lines. Confocal laser scanning microscopy (CLSM) was performed to obtain images of the distribution of CF in Caco-2 cells. These compounds were able to loosen tight junctions, thus increasing paracellular permeability. CLSM confirmed the effect of these absorption enhancers on CF transport across Caco-2 lines and increased the Caco-2 permeability via transcellular route. It was also confirmed that the decrease in TEER was transient and reversible after removal of permeation enhancers. PMID:27429925

  16. Brush border membrane vesicle and Caco-2 cell line: Two experimental models for evaluation of absorption enhancing effects of saponins, bile salts, and some synthetic surfactants.

    PubMed

    Moghimipour, Eskandar; Tabassi, Sayyed Abolghassem Sajadi; Ramezani, Mohammad; Handali, Somayeh; Löbenberg, Raimar

    2016-01-01

    The aim of this study was to investigate the influence of absorption enhancers in the uptake of hydrophilic compounds. The permeation of the two hydrophilic drug models gentamicin and 5 (6)-carboxyfluorescein (CF) across the brush border membrane vesicles and Caco-2 cell lines were evaluated using total saponins of Acanthophyllum squarrosum, Quillaja saponaria, sodium lauryl sulfate, sodium glycocholate, sodium taurodeoxycholate, and Tween 20 as absorption enhancers. Transepithelial electrical resistance (TEER) measurement was utilized to assess the paracellular permeability of cell lines. Confocal laser scanning microscopy (CLSM) was performed to obtain images of the distribution of CF in Caco-2 cells. These compounds were able to loosen tight junctions, thus increasing paracellular permeability. CLSM confirmed the effect of these absorption enhancers on CF transport across Caco-2 lines and increased the Caco-2 permeability via transcellular route. It was also confirmed that the decrease in TEER was transient and reversible after removal of permeation enhancers. PMID:27429925

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

    NASA Technical Reports Server (NTRS)

    Brandt, Niel

    2005-01-01

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

  18. A measurement of the 362 GHz absorption line of Mars atmospheric H 2O 2

    NASA Astrophysics Data System (ADS)

    Clancy, R. T.; Sandor, B. J.; Moriarty-Schieven, G. H.

    2004-03-01

    The 362.156 GHz absorption spectrum of H 2O 2 in the Mars atmosphere was observed on September 4 of 2003, employing the James Clerk Maxwell Telescope (JCMT) sub-millimeter facility on Mauna Kea, Hawaii. Radiative transfer analysis of this line absorption yields an average volume mixing ratio of 18±0.4 ppbv within the lower (0-30 km) Mars atmosphere, in general accordance with standard photochemical models (e.g., Nair et al., 1994, Icarus 111, 124-150). Our derived H 2O 2 abundance is roughly three times greater than the upper limit retrieved by Encrenaz et al. (2002, Astron. Astrophys. 396, 1037-1044) from infrared spectroscopy, although part of this discrepancy may result from the different solar longitudes ( Ls) of observation. Aphelion-to-perihelion thermal forcing of the global Mars hygropause generates substantial (>200%) increases in HO x abundances above ˜10 km altitudes between the Ls=112° period of the Encrenaz et al. upper limit measurement and the current Ls=250° period of detection (Clancy and Nair, 1996, J. Geophys. Res. 101, 12785-12590). The observed H 2O 2 line absorption weakens arguments for non-standard homogeneous (Encrenaz et al., 2002, Astron. Astrophys. 396, 1037-1044) or heterogeneous (Krasnopolsky, 2003a, J. Geophys. Res. 108; 2003b, Icarus 165, 315-325) chemistry, which have been advocated partly on the basis of infrared (8 μm) non-detections for Mars H 2O 2. Observation of Mars H 2O 2 also represents the first measurement of a key catalytic specie in a planetary atmosphere other than our own.

  19. VARIABLE REDDENING AND BROAD ABSORPTION LINES IN THE NARROW-LINE SEYFERT 1 GALAXY WPVS 007: AN ORIGIN IN THE TORUS

    SciTech Connect

    Leighly, Karen M.; Cooper, Erin; Grupe, Dirk; Terndrup, Donald M.; Komossa, S.

    2015-08-10

    We report the discovery of an occultation event in the low-luminosity narrow-line Seyfert 1 galaxy WPVS 007 in 2015 February and March. In concert with longer timescale variability, these observations place strong constraints on the nature and location of the absorbing material. Swift monitoring has revealed a secular decrease since ∼2010 accompanied by flattening of the optical and UV photometry that suggests variable reddening. Analysis of four Hubble Space Telescope COS observations since 2010, including a Director’s Discretionary time observation during the occultation, shows that the broad-absorption-line velocity offset and the C iv emission-line width both decrease as the reddening increases. The occultation dynamical timescale, the BAL variability dynamical timescale, and the density of the BAL gas show that both the reddening material and the broad-absorption-line gas are consistent with an origin in the torus. These observations can be explained by a scenario in which the torus is clumpy with variable scale height, and the BAL gas is blown from the torus material like spray from the crest of a wave. As the obscuring material passes into our line of sight, we alternately see high-velocity broad absorption lines and a clear view to the central engine, or low-velocity broad absorption lines and strong reddening. WPVS 007 has a small black hole mass, and correspondingly short timescales, and so we may be observing behavior that is common in BALQSOs, but is not typically observable.

  20. Multi-Sightline Observation of Narrow Absorption Lines in Lensed Quasar SDSS J1029+2623

    NASA Astrophysics Data System (ADS)

    Misawa, Toru; Saez, Cristian; Charlton, Jane C.; Eracleous, Michael; Chartas, George; Bauer, Franz E.; Inada, Naohisa; Uchiyama, Hisakazu

    2016-07-01

    We exploit the widely separated images of the lensed quasar SDSS J1029+2623 ({z}{em} = 2.197, θ = 22.″5) to observe its outflowing wind through two different sightlines. We present an analysis of three observations, including two with the Subaru telescope in 2010 February and 2014 April, separated by four years, and one with the Very Large Telescope, separated from the second Subaru observation by ˜2 months. We detect 66 narrow absorption lines (NALs), of which 24 are classified as intrinsic NALs that are physically associated with the quasar based on partial coverage analysis. The velocities of intrinsic NALs appear to cluster around values of {v}{ej} ˜ 59,000, 43,000, and 29,000 km s‑1, which is reminiscent of filamentary structures obtained by numerical simulations. There are no common intrinsic NALs at the same redshift along the two sightlines, implying that the transverse size of the NAL absorbers should be smaller than the sightline distance between two lensed images. In addition to the NALs with large ejection velocities of {v}{ej} > 1000 km s‑1, we also detect broader proximity absorption lines (PALs) at {z}{abs} ˜ {z}{em}. The PALs are likely to arise in outflowing gas at a distance of r ≤ 620 pc from the central black hole with an electron density of n e ≥8.7 × 103 cm‑3. These limits are based on the assumption that the variability of the lines is due to recombination. We discuss the implications of these results on the three-dimensional structure of the outflow.

  1. Time-Variable Complex Metal Absorption Lines in the Quasar HS 1603+3820

    NASA Astrophysics Data System (ADS)

    Misawa, Toru; Eracleous, Michael; Charlton, Jane C.; Tajitsu, Akito

    2005-08-01

    We present a new spectrum of the quasar HS 1603+3820 taken 1.28 yr (0.36 yr in the quasar rest frame) after a previous observation with Subaru+HDS. The new spectrum enables us to search for time variability as an identifier of intrinsic narrow absorption lines (NALs). This quasar shows a rich complex of C IV NALs within 60,000 km s-1 of the emission redshift. On the basis of covering factor analysis, Misawa et al. found that the C IV NAL system at zabs=2.42-2.45 (system A, at a shift velocity of vsh=8300-10,600 km s-1 relative to the quasar) was intrinsic to the quasar. With our new spectrum, we perform time variability analysis, as well as covering factor analysis, to separate intrinsic NALs from intervening NALs for eight C IV systems. Only system A, which was identified as an intrinsic system in the earlier paper by Misawa et al., shows a strong variation in line strength (Wobs~10.4-->19.1 Å). We speculate that a broad absorption line (BAL) could be forming in this quasar (i.e., many narrower lines will blend together to make a BAL profile). We illustrate the plausibility of this suggestion with the help of a simulation in which we vary the column densities and covering factors of the NAL complex. Under the assumption that a change of ionization state causes the variability, a lower limit can be placed on the electron density (ne>~3×104cm-3) and an upper limit on the distance from the continuum source (r<=6 kpc). On the other hand, if the motion of clumpy gas causes the variability (a more likely scenario), the crossing velocity and the distance from the continuum source are estimated to be vcross>8000 km s-1 and r<3 pc. In this case, the absorber does not intercept any flux from the broad emission line region, but only flux from the UV continuum source. If we adopt the dynamical model of Murray et al., we can obtain a much more strict constraint on the distance of the gas parcel from the continuum source, r<0.2 pc. Based on data collected at the Subaru

  2. The velocity distribution of interstellar gas observed in strong UV absorption lines

    NASA Technical Reports Server (NTRS)

    Cowie, L. L.; York, D. G.

    1978-01-01

    Observations of three strong interstellar UV absorption lines of N I (1199 A), N II (1083 A), and Si III (1206 A) in 47 stars of widely varying distance and a variety of spectral types are analyzed to obtain a velocity distribution function for the interstellar gas. A technique based on the maximum and minimum velocities observed along a line of sight is adopted because of heavy line blending, and results are discussed for both power-law and exponential distribution functions. The expected distribution of radiative-phase supernova remnants (SNRs) in the interstellar medium is calculated as a function of SNR birthrate and of the interstellar density in which they evolve. The results are combined with observed distance estimates, and it is shown that an interstellar density in excess of 0.1 per cu cm would be required to keep the SNRs sufficiently confined so that their cross sections are consistent with the observed number of components. The alternative possibility is considered that SNRs do not enter the radiative phase before escaping from the Galaxy or colliding with neighboring remnants.

  3. Adsorption studies of Cd(II) onto Al 2O 3/Nb 2O 5 mixed oxide dispersed on silica matrix and its on-line preconcentration and determination by flame atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Mendonça Costa, Lucimara; Ribeiro, Emerson Schwingel; Segatelli, Mariana Gava; do Nascimento, Danielle Raphael; de Oliveira, Fernanda Midori; Tarley, César Ricardo Teixeira

    2011-05-01

    The present study describes the adsorption characteristic of Cd(II) onto Nb 2O 5/Al 2O 3 mixed oxide dispersed on silica matrix. The characterization of the adsorbent has been carried out by infrared spectroscopy (IR), scanning electronic microscopy (SEM), energy dispersive spectroscopy (EDS), energy dispersive X-ray fluorescence analysis (EDXRF) and specific surface area ( SBET). From batch experiments, adsorption kinetic of Cd(II) was described by a pseudo-second-order kinetic model. The Langmuir linear isotherm fitted to the experimental adsorption isotherm very well, and the maximum adsorption capacity was found to be 17.88 mg g -1. Using the effective material, a method for Cd(II) preconcentration at trace level was developed. The method was based on on-line adsorption of Cd(II) onto SiO 2/Al 2O 3/Nb 2O 5 at pH 8.64, in which the quantitative desorption occurs with 1.0 mol L -1 hydrochloric acid towards FAAS detector. The experimental parameters related to the system were studied by means of multivariate analysis, using 2 4 full factorial design and Doehlert matrix. The effect of SO 42-, Cu 2+, Zn 2+ and Ni 2+ foreign ions showed no interference at 1:100 analyte:interferent proportion. Under the most favorable experimental conditions, the preconcentration system provided a preconcentration factor of 18.4 times, consumption index of 1.08 mL, sample throughput of 14 h -1, concentration efficiency of 4.35 min -1, linear range from 5.0 up to 35.0 μg L -1 and limits of detection and quantification of 0.19 and 0.65 μg L -1 respectively. The feasibility of the proposed method for Cd(II) determination was assessed by analysis of water samples, cigarette sample and certified reference materials TORT-2 (Lobster hepatopancreas) and DOLT-4 (Dogfish liver).

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

    SciTech Connect

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

    2006-01-05

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

  5. Unusual high-redshift radio broad absorption-line quasar 1624+3758

    NASA Astrophysics Data System (ADS)

    Benn, C. R.; Carballo, R.; Holt, J.; Vigotti, M.; González-Serrano, J. I.; Mack, K.-H.; Perley, R. A.

    2005-07-01

    We present observations of the most radio-luminous broad absorption-line (BAL) quasar known, 1624+3758, at redshift z= 3.377. The quasar has several unusual properties. (1) The FeII UV191 1787-Åemission line is very prominent. (2) The BAL trough (BALnicity index 2990 km s-1) is detached by 21000 km s-1 and extends to velocity v=-29000 km s-1. There are additional intrinsic absorbers at -1900 and -2800 km s-1. (3) The radio rotation measure of the quasar, 18350 rad m-2, is the second highest known. The radio luminosity is P1.4GHz= 4.3 × 1027 W Hz-1 (H0= 50 km s-1 Mpc-1, q0= 0.5) and the radio loudness is R*= 260. The radio source is compact and the radio spectrum is GHz-peaked, consistent with it being relatively young. The width of the CIV emission line, in conjunction with the total optical luminosity, implies a black hole mass MBH~ 109Msolar, L/LEddington~ 2. The high Eddington ratio and the radio-loudness place this quasar in one corner of Boroson's two-component scheme for the classification of active galactic nuclei, implying a very high accretion rate, and this may account for some of the unusual observed properties. The v=-1900km s-1 absorber is a possible Lyman-limit system, with N(HI) = 4 × 1018 cm-2, and a covering factor of 0.7. A complex mini-BAL absorber at v=-2200 to -3400 km s-1 is detected in each of CIV, NV and OVI. The blue and red components of the CIV doublet happen to be unblended, allowing both the covering factor and optical depth to be determined as a function of velocity. Variation of the covering factor with velocity dominates the form of the mini-BAL, with the absorption being saturated (e-τ~ 0) over most of the velocity range. The velocity dependence of the covering factor and the large velocity width imply that the mini-BAL is intrinsic to the quasar. There is some evidence of line-locking between velocity components in the CIV mini-BAL, suggesting that radiation pressure plays a role in accelerating the outflow.

  6. Absorption lines from magnetically driven winds in X-ray binaries

    NASA Astrophysics Data System (ADS)

    Chakravorty, S.; Petrucci, P.-O.; Ferreira, J.; Henri, G.; Belmont, R.; Clavel, M.; Corbel, S.; Rodriguez, J.; Coriat, M.; Drappeau, S.; Malzac, J.

    2016-05-01

    Context. High resolution X-ray spectra of black hole X-ray binaries (BHBs) show blueshifted absorption lines suggesting the presence of outflowing winds. Furthermore, observations show that the disk winds are equatorial and they occur in the Softer (disk dominated) states of the outburst and are less prominent or absent in the Harder (power-law dominated) states. Aims: We want to test whether the self-similar magneto-hydrodynamic (MHD) accretion-ejection models can explain the observational results for accretion disk winds in BHBs. In our models, the density at the base of the outflow from the accretion disk is not a free parameter. This mass loading is determined by solving the full set of dynamical MHD equations without neglecting any physical term. Thus, the physical properties of the outflow depend on and are controlled by the global structure of the disk. Methods: We studied different MHD solutions characterized by different values of the disk aspect ratio (ɛ) and the ejection efficiency (p). We also generate two kinds of MHD solutions depending on the absence (cold solution) or presence (warm solution) of heating at the disk surface. Such heating could be either from dissipation of energy due to MHD turbulence in the disk or from illumination of the disk surface. Warm solutions can have large (>0.1) values of p, which would imply larger wind mass loading at the base of the outflow. We use each of these MHD solutions to predict the physical parameters (distance, density, velocity, magnetic field, etc.) of an outflow. Motivated by observational results, we have put limits on the ionization parameter (ξ), column density, and timescales. Further constraints were derived for the allowed values of ξ from thermodynamic instability considerations, particularly for the Hard SED. These physical constraints were imposed on each of these outflows to select regions within it, which are consistent with the observed winds. Results: The cold MHD solutions are found to be

  7. The hydration dependence of CaCO3 absorption lines in the Far IR

    NASA Astrophysics Data System (ADS)

    Powell, Johnny; Emery, Logan P

    2014-06-01

    The far infrared (FIR) absorption lines of CaCO3 have been measured at a range of relative humidities (RH) between 33 and 92% RH using a Bruker 66v/S spectrometer. Hydration measurements on CaCO3 have been made in the mid-infrared (MIR) by [Al-Hosney, H.A. and Grassian, V.H., 2005, Phys. Chem. Chem. Phys., 7, 1266], and astrophysically-motivated temperature-dependent FIR measurements of CaCO3 in vacuum have also been reported [Posch, T., et al., 2007, Ap. J., 668, 993]. The custom sample cell constructed for these hydrated-FIR spectra is required because the 66v/S bench is under vacuum (3 mbar) during typical measurements. Briefly, the sample cell consists of two Thalium Bromoiodide (KRS-5) windows, four O-rings, a plastic ring for separating the windows and providing a volume for the saturated atmosphere. CaCO3 was deposited on KRS-5 windows using doubly-distilled water as an intermediary. The KRS-5 window with sample and assembled sample cell were placed in a desiccator with the appropriated saturated salt solution [Washburn, E.W. (Ed.), International Critical Tables of Numerical Data, Physics Chemistry and Technology, Vol. 1, (McGraw-Hill, New York, 1926), p. 67-68] and allowed to hydrate for 23 hours. For spectroscopy the desiccator was quickly opened and the second KRS-5 window placed in the cell to seal the chamber. A spectrum was then taken of the sample at the appropriate RH. The spectra taken characterize the adsorption of water vapor and CaCO3 that might occur in circumstellar environments [Melnick, G.J., et al. 2001, Nature, 412, 160].The MIR and FIR reflectance spectra of calcite (CaCO3) have been thoroughly studied by [Hellwege, K.H., et al., 1970, Z. Physik, 232, 61]. Five Lorentzian curves were fit to our data in the range from 378-222 cm-1/SUP> and each was able to be assigned to a known mode of CaCO3. The data does not support the conclusion of a hydration effect on these modes of CaCO3, but it does suggest a possible broadening of three modes

  8. Broad Absorption Line Variability on Multi-Year Timescales in a Large Quasar Sample

    NASA Astrophysics Data System (ADS)

    Brandt, W. N.; Filiz Ak, N.; Hall, P. B.; Schneider, D. P.; SDSS-III BAL Variability Team

    2014-01-01

    We have performed a detailed investigation of the variability of 428 C IV and 235 Si IV Broad Absorption Line (BAL) troughs identified in multi-epoch observations of 291 quasars by the Sloan Digital Sky Survey-I/II/III. These observations primarily sample rest-frame timescales of 1-3 yr over which significant rearrangement of the BAL wind is expected. We derive a number of observational results on, e.g., the frequency of BAL variability, the velocity range over which BAL variability occurs, the primary observed form of BAL-trough variability, the dependence of BAL variability upon timescale, the frequency of BAL strengthening vs. weakening, correlations between BAL variability and BAL-trough profiles, relations between C IV and Si IV BAL variability, coordinated multi-trough variability, and BAL variations as a function of quasar properties. We assess implications of these observational results for quasar winds. Our results support models where most BAL absorption is formed within an order-of-magnitude of the wind-launching radius, although a significant minority of BAL troughs may arise on larger scales. We estimate an average lifetime for a BAL trough along our line-of-sight of a few thousand years. BAL disappearance and emergence events appear to be extremes of general BAL variability, rather than being qualitatively distinct phenomena. We derive the parameters of a random-walk model for BAL EW variability, finding that this model can acceptably describe some key aspects of EW variability. The coordinated trough variability of BAL quasars with multiple troughs suggests that changes in "shielding gas" may play a significant role in driving general BAL variability. The good prospects for significantly extending this work will be briefly summarized.

  9. THE STELLAR INITIAL MASS FUNCTION IN EARLY-TYPE GALAXIES FROM ABSORPTION LINE SPECTROSCOPY. II. RESULTS

    SciTech Connect

    Conroy, Charlie; Van Dokkum, Pieter G.

    2012-11-20

    The spectral absorption lines in early-type galaxies contain a wealth of information regarding the detailed abundance pattern, star formation history, and stellar initial mass function (IMF) of the underlying stellar population. Using our new population synthesis model that accounts for the effect of variable abundance ratios of 11 elements, we analyze very high quality absorption line spectra of 38 early-type galaxies and the nuclear bulge of M31. These data extend to 1 {mu}m and they therefore include the IMF-sensitive spectral features Na I, Ca II, and FeH at 0.82 {mu}m, 0.86 {mu}m, and 0.99 {mu}m, respectively. The models fit the data well, with typical rms residuals {approx}< 1%. Strong constraints on the IMF and therefore the stellar mass-to-light ratio, (M/L){sub stars}, are derived for individual galaxies. We find that the IMF becomes increasingly bottom-heavy with increasing velocity dispersion and [Mg/Fe]. At the lowest dispersions and [Mg/Fe] values the derived IMF is consistent with the Milky Way (MW) IMF, while at the highest dispersions and [Mg/Fe] values the derived IMF contains more low-mass stars (is more bottom-heavy) than even a Salpeter IMF. Our best-fit (M/L){sub stars} values do not exceed dynamically based M/L values. We also apply our models to stacked spectra of four metal-rich globular clusters in M31 and find an (M/L){sub stars} that implies fewer low-mass stars than a MW IMF, again agreeing with dynamical constraints. We discuss other possible explanations for the observed trends and conclude that variation in the IMF is the simplest and most plausible.

  10. A variable P v broad absorption line and quasar outflow energetics

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    Broad absorption lines (BALs) in quasar spectra identify high-velocity outflows that might exist in all quasars and could play a major role in feedback to galaxy evolution. The viability of BAL outflows as a feedback mechanism depends on their kinetic energies, as derived from the outflow velocities, column densities, and distances from the central quasar. We estimate these quantities for the quasar, Q1413+1143 (redshift ze = 2.56), aided by the first detection of P V λλ1118, 1128 BAL variability in a quasar. In particular, P V absorption at velocities where the C IV trough does not reach zero intensity implies that the C IV BAL is saturated and the absorber only partially covers the background continuum source (with characteristic size <0.01 pc). With the assumption of solar abundances, we estimate that the total column density in the BAL outflow is log NH ≳ 22.3 cm-2. Variability in the P V and saturated C IV BALs strongly disfavours changes in the ionization as the cause of the BAL variability, but supports models with high column density BAL clouds moving across our lines of sight. The observed variability time of 1.6 yr in the quasar rest frame indicates crossing speeds >750 km s-1 and a radial distance from the central black hole of ≲ 3.5 pc, if the crossing speeds are Keplerian. The total outflow mass is ˜4100 M⊙, the kinetic energy ˜4 × 1054 erg, and the ratio of the outflow kinetic energy luminosity to the quasar bolometric luminosity is ˜0.02 (at the minimum column density and maximum distance), which might be sufficient for important feedback to the quasar's host galaxy.

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

    SciTech Connect

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

    2013-11-10

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

  13. Sharp R-lines in absorption and emission of Cr3 in stoichiometric (VTE) LiNbO3

    NASA Astrophysics Data System (ADS)

    Fischer, C.; Kapphan, S.; Feng, Xi-Qi; Cheng, Ning

    R-line absorption and luminescence spectra of Cr3+ doped LiNbO3 show a distinct dependence on crystal stoichiometry. In the Cr3+ R-line region around 730 nm, up to five transitions can be observed in absorption and emission. In stoichiometric LiNbO3:Cr crystals the line width (FWHM) in both absorption and emission decreases by about a factor of 2.5 in comparison with the same transitions in congruent samples. The emission line at lowest energy in the R-line spectrum (λ = 734.5 nm) disappears completely in stoichiometric LiNbO3:Cr. This results, discussed together with models dealing with charge compensated Cr3+ pairs on Li and Nb sites and unpaired Cr3+ on Li site, is indicating a vanishing of the unpaired Cr3+Li with increasing [Li]/[Nb] ratio. Luminescence lifetime measurements in stoichiometric LiNbO3:Cr reveal values similar to results for congruent material of τ = 295 μs for the 731 nm line and τ = 268 μs for the 735 nm line, underlining the R-line character of these transitions.

  14. Impact of difference in absorption line parameters in spectroscopic databases on CO2 and CH4 atmospheric content retrievals

    NASA Astrophysics Data System (ADS)

    Chesnokova, T. Yu.; Chentsov, A. V.; Rokotyan, N. V.; Zakharov, V. I.

    2016-09-01

    The impact of uncertainties in CH4 and CO2 absorption line parameters in modern spectroscopic databases on the atmospheric transmission simulation in the near-infrared region is investigated. The atmospheric contents of CH4 and CO2 are retrieved from the absorption solar spectra measured by a ground-based Fourier transform spectrometer. Different spectroscopic databases are used in the forward radiative transfer model and a comparison of the retrieved results is made.

  15. Experimental study of neutrino absorption on carbon

    SciTech Connect

    Krakauer, D.A.; Talaga, R.L. ); Allen, R.C.; Chen, H.H.; Hausammann, R.; Lee, W.P.; Mahler, H.J.; Lu, X.Q.; Wang, K.C. ); Bowles, T.J.; Burman, R.L.; Carlini, R.D.; Cochran, D.R.F.; Doe, P.J.; Frank, J.S.; Piasetzky, E.; Potter, M.E.; Sandberg, V.D. )

    1992-05-01

    The process of electron emission from {similar to}30 MeV neutrino absorption on carbon, {sup 12}C({nu}{sub {ital e}},{ital e}{sup {minus}}){sup 12}N, has been observed. The flux-weighted total cross section for the exclusive neutrino-induced nuclear transition {sup 12}C({nu}{sub {ital e}},{ital e}{sup {minus}}){sup 12}N(g.s.) is (1.05{plus minus}0.10(stat){plus minus}0.10(syst)){times}10{sup {minus}41} cm{sup 2}. The measured cross section and angular distribution {ital d}{sigma}/{ital d}{Omega} are in agreement with theoretical estimates. The inclusive {nu}{sub {ital e}} {sup 12}C reaction rate, which accounted for the majority of all neutrino interactions observed in this experiment, was determined from a detailed fit of energy and angular distributions for the observed electrons. The inclusive {sup 12}C({nu}{sub {ital e}},{ital e}{sup {minus}}){ital X} cross section is measured to be (1.41{plus minus}0.23(tot)){times}10{sup {minus}41} cm{sup 2}. An upper limit for the sum of the {sup 13}C({nu}{sub {ital e}},{ital e}{sup {minus}}){ital X}+{sup 27}Al({nu}{sub {ital e}},{ital e}{sup {minus}}){ital X} inclusive absorption cross sections is presented.

  16. A novel control system for automatically locking a diode laser frequency to a selected gas absorption line

    NASA Astrophysics Data System (ADS)

    Dong, Lei; Yin, Wangbao; Ma, Weiguang; Jia, Suotang

    2007-05-01

    A novel control system has been developed for avoiding manual operation during traditional frequency locking. The control system uses a computer with a commercial data acquisition card. This accomplishes the whole operation of frequency locking, including generating ramp, searching locking point, engaging a proportional-integral-differential (PID) regulator at the proper time and outputting PID compensation signal. Moreover, a new method has also been employed to make the novel control system accurately identify the locking points of all absorption lines within the scanning range, so that the laser frequency can be automatically firmly brought onto any selected absorption line centre without any adjusting time. The operation of the system, the ability to identify absorption lines and the performance of the frequency locking were discussed in detail. Successful tests were made with two different lasers: external cavity diode lasers and distributed feedback diode lasers.

  17. Gravitationally redshifted absorption lines in the X-ray burst spectra of a neutron star.

    PubMed

    Cottam, J; Paerels, F; Mendez, M

    2002-11-01

    The fundamental properties of neutron stars provide a direct test of the equation of state of cold nuclear matter, a relationship between pressure and density that is determined by the physics of the strong interactions between the particles that constitute the star. The most straightforward method of determining these properties is by measuring the gravitational redshift of spectral lines produced in the neutron star photosphere. The equation of state implies a mass-radius relation, while a measurement of the gravitational redshift at the surface of a neutron star provides a direct constraint on the mass-to-radius ratio. Here we report the discovery of significant absorption lines in the spectra of 28 bursts of the low-mass X-ray binary EXO0748-676. We identify the most significant features with the Fe XXVI and XXV n = 2-3 and O VIII n = 1-2 transitions, all with a redshift of z = 0.35, identical within small uncertainties for the respective transitions. For an astrophysically plausible range of masses (M approximately 1.3-2.0 solar masses; refs 2-5), this value is completely consistent with models of neutron stars composed of normal nuclear matter, while it excludes some models in which the neutron stars are made of more exotic matter. PMID:12422210

  18. Dramatically Variable C IV Mini-Broad Absorption Line System in the Quasar HS 1603+3820

    NASA Astrophysics Data System (ADS)

    Misawa, T.; Eracleous, M.; Charlton, J. C.; Chartas, G.; Kashikawa, N.

    2008-10-01

    We observed the quasar HS 1603+3820 (z_{em} = 2.542, first discovered by Dobrzycki et al. 1996) six times over an interval of 4.2 yrs (1.2 yrs in the quasar rest frame) using the High Dispersion Spectrograph on Subaru telescope. The purpose was to study the mini-broad absorption line (mini-BAL; FWHM ˜ 1,000 km s^{-1}) that is blue-shifted from the quasar by ˜ 9,500 km s^{-1}. We found significant time variability, which supported the physical association of the mini-BAL gas with an outflow from the quasar. We have narrowed down the cause of the variability to two possible scenarios. We also used archival Chandra x-ray data to study the x-ray properties of this quasar. The results constrain the location of the absorbing gas relative to the overall outflow.

  19. Abundances of O, Mg, S, Cr, Mn, Ti, Ni and Zn from absorption lines of neutral gas in the Large Magellanic Cloud in front of R136

    NASA Technical Reports Server (NTRS)

    De Boer, K. S.; Fitzpatrick, E. L.; Savage, B. D.

    1985-01-01

    Weak absorption lines of C I, O I, Mg I, Mg II, Si I, Si II, P I, Cl I, Cr II, Mn II, Fe I, Ni II, Zn II, CO and C2 are detected in neutral gas in front of the 30 Doradus H II region by IUE spectra of R 136. The Large Magellanic Cloud abundances from the absorption lines are a factor of 2 or 3 below those of the Milky Way, in agreement with emission line study results. Neutral gas density and temperature are estimated from the observed excitation and ionization to be about 300/cu cm and 100 K, respectively; this implies a gas pressure of 30,000/cu cm K.

  20. First detection of ionized helium absorption lines in infrared K band spectra of O-type stars

    NASA Technical Reports Server (NTRS)

    Conti, Peter S.; Block, David L.; Geballe, T. R.; Hanson, Margaret M.

    1993-01-01

    We have obtained high SNR, moderate-resolution K band spectra of two early O-type main sequence stars, HD 46150 O5 V, and HD 46223 O4 V, in the Rosette Nebula. We report the detection, for the first time, of the 2.189 micron He II line in O-type stars. Also detected is the 2.1661 micron Br-gamma line in absorption. The 2.058 micron He I line appears to be present in absorption in both stars, although its appearance at our resolution is complicated by atmospheric features. These three lines can form the basis for a spectral classification system for hot stars in the K band that may be used at infrared wavelengths to elucidate the nature of those luminous stars in otherwise obscured H II and giant H II regions.

  1. Dependence of the Broad Absorption Line Quasar Fraction on Radio Luminosity

    NASA Astrophysics Data System (ADS)

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

    2008-11-01

    We find that the fraction of classical broad absorption line quasars (BALQSOs) among the FIRST radio sources in the Sloan Data Release 3, is 20.5+ 7.3-5.9% at the faintest radio powers detected (L1.4 GHz ~ 1032 erg s-1), and rapidly drops to lesssim8% at L1.4 GHz ~ 3 × 1033 erg s-1. Similarly, adopting the broader absorption index (AI) definition of Trump et al., we find the fraction of radio BALQSOs to be 44+ 8.1-7.8%, reducing to 23.1+ 7.3-6.1% at high luminosities. While the high fraction at low radio power is consistent with the recent near-IR estimates by Dai et al., the lower fraction at high radio powers is intriguing and confirms previous claims based on smaller samples. The trend is independent of the redshift range, the optical and radio flux selection limits, or the exact definition of a radio match. We also find that at fixed optical magnitude, the highest bins of radio luminosity are preferentially populated by non-BALQSOs, consistent with the overall trend. We do find, however, that those quasars identified as AI-BALQSOs but not under the classical definition do not show a significant drop in their fraction as a function of radio power, further supporting independent claims that these sources, characterized by lower equivalent width, may represent an independent class from the classical BALQSOs. We find the balnicity index, a measure of the absorption trough in BALQSOs, and the mean maximum wind velocity to be roughly constant at all radio powers. We discuss several plausible physical models which may explain the observed fast drop in the fraction of the classical BALQSOs with increasing radio power, although none is entirely satisfactory. A strictly evolutionary model for the BALQSO and radio emission phases requires a strong fine-tuning to work, while a simple geometric model, although still not capable of explaining polar BALQSOs and the paucity of FRII BALQSOs, is statistically successful in matching the data if part of the apparent radio

  2. Experimental studies of a zeeman-tuned xenon laser differential absorption apparatus.

    PubMed

    Linford, G J

    1973-06-01

    A Zeeman-tuned cw xenon laser differential absorption device is described. The xenon laser was tuned by axial magnetic fields up to 5500 G generated by an unusually large water-cooled dc solenoid. Xenon laser lines at 3.37 micro, 3.51 micro, and 3.99 micro were tuned over ranges of 6 A, 6 A, and 11 A, respectively. To date, this apparatus has been used principally to study the details of formaldehyde absorption lines lying near the 3 .508-micro xenon laser transition. These experiments revealed that the observed absorption spectrum of formaldehyde exhibits a sufficiently unique spectral structure that the present technique may readily be used to measure relative concentrations of formaldehyde in samples of polluted air.

  3. Evidence for two spatially separated UV continuum emitting regions in the Cloverleaf broad absorption line quasar

    NASA Astrophysics Data System (ADS)

    Sluse, D.; Hutsemékers, D.; Anguita, T.; Braibant, L.; Riaud, P.

    2015-10-01

    Testing the standard Shakura-Sunyaev model of accretion is a challenging task because the central region of quasars where accretion takes place is unresolved with telescopes. The analysis of microlensing in gravitationally lensed quasars is one of the few techniques that can test this model, yielding to the measurement of the size and of temperature profile of the accretion disc. We present spectroscopic observations of the gravitationally lensed broad absorption line quasar H1413+117, which reveal partial microlensing of the continuum emission that appears to originate from two separated regions: a microlensed region, corresponding the compact accretion disc; and a non-microlensed region, more extended and contributing to at least 30% of the total UV-continuum flux. Because this extended continuum is occulted by the broad absorption line clouds, it is not associated with the host galaxy, but rather with light scattered in the neighbourhood of the central engine. We measure the amplitude of microlensing of the compact continuum over the rest-frame wavelength range 1000-7000 Å. Following a Bayesian scheme, we confront our measurements to microlensing simulations of an accretion disc with a temperature varying as T ∝ R-1/ν. We find a most likely source half-light radius of R1/2 = 0.61 × 1016cm (i.e., 0.002 pc) at 0.18 μm, and a most-likely index of ν = 0.4. The standard disc (ν = 4/3) model is not ruled out by our data, and is found within the 95% confidence interval associated with our measurements. We demonstrate that, for H1413+117, the existence of an extended continuum in addition to the disc emission only has a small impact on the inferred disc parameters, and is unlikely to solve the tension between the microlensing source size and standard disc sizes, as previously reported in the literature. Based on observations made with ESO Telescopes at the Paranal Observatory (Chile). ESO program ID: 386.B-0337.Appendices A and B are available in electronic form

  4. Detection of harmonics and recovery of the absorption line profile using logarithmic-transformed wavelength modulation spectroscopy

    NASA Astrophysics Data System (ADS)

    Cong, Menglong; Sun, Dandan

    2016-07-01

    A versatile signal processing strategy for eliminating the residual amplitude modulation (RAM) and distortion in tunable diode laser wavelength modulation spectroscopy is theoretically demonstrated and experimentally validated. The strategy involves logarithmic transformation and differential detection, which are achieved using a homemade circuit. Through the logarithmic transformation, the optical intensity modulation of the laser, which performs as the source of RAM and distortion, is separated from the absorption-induced power attenuation and further balanced during the differential detection. The first harmonic, which is proportional to the first-order derivative of the absorption line profile in the case of a small modulation index, is extracted along with the second harmonic and is integrated for the recovery of the absorption line profile. The experiments are carried out for CH4 at its R(3) absorption line of the 2ν3 overtone for validation of the system, and the derived results are found to be in good agreement with the theoretical simulations. These promising results indicate the high potential of the strategy for absorption spectrum-based determination of gas properties.

  5. Millimeter-wave Absorption Studies of Molecules in Diffuse Clouds

    NASA Astrophysics Data System (ADS)

    Lucas, Robert; Liszt, Harvey S.

    1999-10-01

    With IRAM instruments in the last few years, we have been using compact extragalactic millimeter wave radio sources as background objects to study the absorption spectrum of diffuse interstellar gas at millimeter wavelengths. The molecular content of interstellar gas has turned out to be unexpectedly rich. Simple polyatomic molecules such as HCO+, C2H are quite ubiquitous near the Galactic plane (beta < 15o), and many species are detected in some directions (CO, HCO+, H2CO, HCN, HNC, CN, C2H, C3H2, H2S, CS, HCS+, SO, SiO). Remarkable proportionality relations are found between related species such as HCO+ and OH, or CN, HCN and HNC. The high abundance of some species is still a challenge for current models of diffuse cloud chemistry. A factor of 10 increase in the sensitivity will make such studies achievable in denser clouds, where the chemistry is still more active and where abundances are nowadays only available by emission measurements, and thus subject to uncertainties due to sometimes poorly understood line formation and excitation conditions.

  6. Application of flow injection on-line electrothermal atomic absorption spectrometry to the determination of rhodium.

    PubMed

    Sanchez Rojas, Fuensanta; Bosch Ojeda, Catalina; Cano Pavón, José Manuel

    2005-06-01

    A fully automated procedure for the determination of rhodium has been developed using flow injection (FI) on-line microcolumn preconcentration coupled with electrothermal atomic absorption spectrometry (ETAAS). The proposed FI manifold and its operation make possible the introduction of the total eluate volume into the graphite atomizer, avoiding the necessity for optimisation of subsampling the eluate. Rhodium is adsorbed on a microcolumn packed with 1,5-bis(di-2-pyridyl)methylene thiocarbohydrazide immobilized on silica gel (DPTH-gel). Under the optimum conditions, using a 60 s preconcentration time, a sample flow rate of 3.5 mL min(-1) and an injection volume of eluent of 50 microL, a linear calibration graph was obtained from 1 to at least 40 ng mL(-1) and the detection limit was 1 ng mL(-1). The proposed method has been successfully applied to the analysis of samples. Its performance was investigated against certified reference catalyst sample SRM-2557 and by recovery measurements on spiked samples (soil, foods and beverages).

  7. MOSFIRE ABSORPTION LINE SPECTROSCOPY OF z > 2 QUIESCENT GALAXIES: PROBING A PERIOD OF RAPID SIZE GROWTH

    SciTech Connect

    Belli, Sirio; Ellis, Richard S.; Konidaris, Nick P.; Newman, Andrew B.

    2014-06-20

    Using the MOSFIRE near-infrared multi-slit spectrograph on the Keck 1 Telescope, we have secured high signal-to-noise ratio absorption line spectra for six massive galaxies with redshift 2 < z < 2.5. Five of these galaxies lie on the red sequence and show signatures of passive stellar populations in their rest-frame optical spectra. By fitting broadened spectral templates we have determined stellar velocity dispersions and, with broad-band Hubble Space Telescope and Spitzer photometry and imaging, stellar masses and effective radii. Using this enlarged sample of galaxies, we confirm earlier suggestions that quiescent galaxies at z > 2 have small sizes and large velocity dispersions compared to local galaxies of similar stellar mass. The dynamical masses are in very good agreement with stellar masses (log M {sub *}/M {sub dyn} = –0.02 ± 0.03), although the average stellar-to-dynamical mass ratio is larger than that found at lower redshift (–0.23 ± 0.05). By assuming evolution at fixed velocity dispersion, not only do we confirm a surprisingly rapid rate of size growth but we also consider the necessary evolutionary track on the mass-size plane and find a slope α = dlog R{sub e} /dlog M {sub *} ≳ 2 inconsistent with most numerical simulations of minor mergers. Both results suggest an additional mechanism may be required to explain the size growth of early galaxies.

  8. Fast outflows in broad absorption line quasars and their connection with CSS/GPS sources

    NASA Astrophysics Data System (ADS)

    Bruni , G.; Mack, K.-H.; Montenegro-Montes, F. M.; Brienza, M.; González-Serrano, J. I.

    2016-02-01

    Broad absorption line quasars are among the objects presenting the fastest outflows. The launching mechanism itself is not completely understood. Models in which they could be launched from the accretion disk, and then curved and accelerated by the effect of the radiation pressure, have been presented. We conducted an extensive observational campaign, from radio to optical band, to collect information about their nature and test the models present in the literature, the main dichotomy being between a young scenario and an orientation one. We found a variety of possible orientations, morphologies, and radio ages, not converging to a particular explanation for the BAL phenomenon. From our latest observations in the m- and mm-band, we obtained an indication of a lower dust abundance with respect to normal quasars, thus suggesting a possible feedback process on the host galaxy. Also, in the low-frequency regime we confirmed the presence of CSS components, sometime in conjunction with a GPS one already detected at higher frequencies. Following this, about 70 % of our sample turns out to be in a GPS or CSS+GPS phase. We conclude that fast outflows, responsible for the BAL features, can be more easily present among objects going through a restarting or just-started radio phase, where radiation pressure can substantially contribute to their acceleration.

  9. CHANDRA VIEW OF THE WARM-HOT INTERGALACTIC MEDIUM TOWARD 1ES 1553+113: ABSORPTION-LINE DETECTIONS AND IDENTIFICATIONS. I

    SciTech Connect

    Nicastro, F.; Zappacosta, L.; Elvis, M.; Krongold, Y.; Mathur, S.; Gupta, A.; Danforth, C.; Shull, J. M.; Barcons, X.; Borgani, S.; Branchini, E.; Cen, R.; Dave, R.; Kaastra, J.; Paerels, F.; Piro, L.; Takei, Y.

    2013-06-01

    We present the first results from our pilot 500 ks Chandra Low Energy Transmission Grating Large Program observation of the soft X-ray brightest source in the z {approx}> 0.4 sky, the blazar 1ES 1553+113, aimed to secure the first uncontroversial detections of the missing baryons in the X-rays. We identify a total of 11 possible absorption lines, with single-line statistical significances between 2.2{sigma} and 4.1{sigma}. Six of these lines are detected at high single-line statistical significance (3.6 {<=} {sigma} {<=} 4.1), while the remaining five are regarded as marginal detections in association with either other X-ray lines detected at higher significance and/or far-ultraviolet (FUV) signposts. Three of these lines are consistent with metal absorption at z {approx_equal} 0, and we identify them with Galactic O I and C II. The remaining eight lines may be imprinted by intervening absorbers and are all consistent with being high-ionization counterparts of FUV H I and/or O VI intergalactic medium signposts. In particular, five of these eight possible intervening absorption lines (single-line statistical significances of 4.1{sigma}, 4.1{sigma}, 3.9{sigma}, 3.8{sigma}, and 2.7{sigma}), are identified as C V and C VI K{alpha} absorbers belonging to three WHIM systems at z{sub X} = 0.312, z{sub X} = 0.237, and (z{sub X} ) = 0.133, which also produce broad H I (and O VI for the z{sub X} = 0.312 system) absorption in the FUV. For two of these systems (z{sub X} = 0.312 and 0.237), the Chandra X-ray data led the a posteriori discovery of physically consistent broad H I associations in the FUV (for the third system the opposite applies), so confirming the power of the X-ray-FUV synergy for WHIM studies. The true statistical significances of these three X-ray absorption systems, after properly accounting for the number of redshift trials, are 5.8{sigma} (z{sub X} = 0.312; 6.3{sigma} if the low-significance O V and C V K{beta} associations are considered), 3.9{sigma} (z

  10. NARROW Na AND K ABSORPTION LINES TOWARD T TAURI STARS: TRACING THE ATOMIC ENVELOPE OF MOLECULAR CLOUDS

    SciTech Connect

    Pascucci, I.; Simon, M. N.; Edwards, S.; Heyer, M.; Rigliaco, E.; Hillenbrand, L.; Gorti, U.; Hollenbach, D.

    2015-11-20

    We present a detailed analysis of narrow Na i and K i absorption resonance lines toward nearly 40 T Tauri stars in Taurus with the goal of clarifying their origin. The Na i λ5889.95 line is detected toward all but one source, while the weaker K i λ7698.96 line is detected in about two-thirds of the sample. The similarity in their peak centroids and the significant positive correlation between their equivalent widths demonstrate that these transitions trace the same atomic gas. The absorption lines are present toward both disk and diskless young stellar objects, which excludes cold gas within the circumstellar disk as the absorbing material. A comparison of Na i and CO detections and peak centroids demonstrates that the atomic gas and molecular gas are not co-located, the atomic gas being more extended than the molecular gas. The width of the atomic lines corroborates this finding and points to atomic gas about an order of magnitude warmer than the molecular gas. The distribution of Na i radial velocities shows a clear spatial gradient along the length of the Taurus molecular cloud filaments. This suggests that absorption is associated with the Taurus molecular cloud. Assuming that the gradient is due to cloud rotation, the rotation of the atomic gas is consistent with differential galactic rotation, whereas the rotation of the molecular gas, although with the same rotation axis, is retrograde. Our analysis shows that narrow Na i and K i absorption resonance lines are useful tracers of the atomic envelope of molecular clouds. In line with recent findings from giant molecular clouds, our results demonstrate that the velocity fields of the atomic and molecular gas are misaligned. The angular momentum of a molecular cloud is not simply inherited from the rotating Galactic disk from which it formed but may be redistributed by cloud–cloud interactions.

  11. Radiant energy absorption studies for laser propulsion. [gas dynamics

    NASA Technical Reports Server (NTRS)

    Caledonia, G. E.; Wu, P. K. S.; Pirri, A. N.

    1975-01-01

    A study of the energy absorption mechanisms and fluid dynamic considerations for efficient conversion of high power laser radiation into a high velocity flow is presented. The objectives of the study are: (1) to determine the most effective absorption mechanisms for converting laser radiation into translational energy, and (2) to examine the requirements for transfer of the absorbed energy into a steady flow which is stable to disturbances in the absorption zone. A review of inverse Bremsstrahlung, molecular and particulate absorption mechanisms is considered and the steady flow and stability considerations for conversion of the laser power to a high velocity flow in a nozzle configuration is calculated. A quasi-one-dimensional flow through a nozzle was formulated under the assumptions of perfect gas.

  12. Energy absorption studied to reduce aircraft crash forces

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The NASA/FAA aircraft safety reseach programs for general aviation aircraft are discussed. Energy absorption of aircraft subflooring and redesign of interior flooring are being studied. The testing of energy absorbing configurations is described. The three NASA advanced concepts performed at neary the maximum possible amount of energy absorption, and one of two minimum modifications concepts performed well. Planned full scale tests are described. Airplane seat concepts are being considered.

  13. Impact of broadened laser line-shape on retrievals of atmospheric species from lidar sounding absorption spectra.

    PubMed

    Chen, Jeffrey R; Numata, Kenji; Wu, Stewart T

    2015-02-01

    We examine the impact of broadened laser line-shape on retrievals of atmospheric species from lidar-sounding absorption spectra. The laser is assumed to be deterministically modulated into a stable, nearly top-hat frequency comb to suppress the stimulated Brillouin scattering, allowing over 10-fold pulse energy increase without adding measurement noise. Our model remains accurate by incorporating the laser line-shape factor into the effective optical depth. Retrieval errors arising from measurement noise and model bias are analyzed parametrically and numerically to provide deeper insight. The stable laser line-shape broadening minimally degrades the column-averaged retrieval, but can significantly degrade the multiple-layer retrievals.

  14. Highly Ionized Iron Absorption Lines from Outflowing Gases in the X-ray Spectrum of NGC 1365

    NASA Technical Reports Server (NTRS)

    Risaliti, G.; Bianchi, S.; Matt, G.; Baldi, A.; Elvis, M.; Fabbiano, G.; Zezas, A.

    2006-01-01

    We present the discovery of four absorption lines in the X-ray spectrum of the Seyfert galaxy NGC 1365, at energies between 6.7 and 8.3 keV. The lines are detected with high statistical confidence (from >20 sigma for the strongest to -4 sigma for the weakest) in two XMM-Newton observations 60 ks long. We also detect the same lines, with a lower signal-to-noise ratio (but still >2 sigma for each line), in two previous shorter (-10 ks) XMM-Newton observations. The spectral analysis identifies these features as Fe XXV and Fe XXVI Kalpha and Kbeta lines, outflowing with velocities varying between -1000 and -5000 km/s among the observations. These are the highest quality detections of such lines so far. The high equivalent widths [EW (Kalpha) approximately 100 eV] and the Kalpha/Kbeta ratios imply that the lines are due to absorption of the AGN continuum by a highly ionized gas with column density NH-5?1023 cm(exp -2) at a distance of -(50-100)RS from the continuum source.

  15. Detection of carbon monoxide and water absorption lines in an exoplanet atmosphere.

    PubMed

    Konopacky, Quinn M; Barman, Travis S; Macintosh, Bruce A; Marois, Christian

    2013-03-22

    Determining the atmospheric structure and chemical composition of an exoplanet remains a formidable goal. Fortunately, advancements in the study of exoplanets and their atmospheres have come in the form of direct imaging--spatially resolving the planet from its parent star--which enables high-resolution spectroscopy of self-luminous planets in jovian-like orbits. Here, we present a spectrum with numerous, well-resolved molecular lines from both water and carbon monoxide from a massive planet orbiting less than 40 astronomical units from the star HR 8799. These data reveal the planet's chemical composition, atmospheric structure, and surface gravity, confirming that it is indeed a young planet. The spectral lines suggest an atmospheric carbon-to-oxygen ratio that is greater than that of the host star, providing hints about the planet's formation.

  16. Detection of carbon monoxide and water absorption lines in an exoplanet atmosphere.

    PubMed

    Konopacky, Quinn M; Barman, Travis S; Macintosh, Bruce A; Marois, Christian

    2013-03-22

    Determining the atmospheric structure and chemical composition of an exoplanet remains a formidable goal. Fortunately, advancements in the study of exoplanets and their atmospheres have come in the form of direct imaging--spatially resolving the planet from its parent star--which enables high-resolution spectroscopy of self-luminous planets in jovian-like orbits. Here, we present a spectrum with numerous, well-resolved molecular lines from both water and carbon monoxide from a massive planet orbiting less than 40 astronomical units from the star HR 8799. These data reveal the planet's chemical composition, atmospheric structure, and surface gravity, confirming that it is indeed a young planet. The spectral lines suggest an atmospheric carbon-to-oxygen ratio that is greater than that of the host star, providing hints about the planet's formation. PMID:23493423

  17. Unveiling the intrinsic X-ray properties of broad absorption line quasars with a relatively unbiased sample

    SciTech Connect

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

    2014-05-01

    There is growing evidence of a higher intrinsic fraction of broad absorption line quasars (BALQSOs) than that obtained in optical surveys, on which most previous X-ray studies of BALQSOs have focused. Here we present Chandra observations of 18 BALQSOs at z ∼ 2, selected from a near-infrared (Two Micron All Sky Survey) sample, where the BALQSO fraction is likely to be close to the intrinsic fraction. We measure photon indices using the stacked spectra of the optically faint (i – K{sub s} ≥ 2.3 mag) and optically bright (i – K{sub s} < 2.3 mag) samples to be Γ ≅ 1.5-2.1. We constrain their intrinsic column density by modeling the X-ray fractional hardness ratio, finding a mean column density of 3.5 × 10{sup 22} cm{sup –2} assuming neutral absorption. We incorporate Sloan Digital Sky Survey optical measurements (rest frame UV) to study the broadband spectral index between the X-ray and UV bands, and compare this to a large sample of normal quasars. We estimate that the optically faint BALQSOs are X-ray weaker than the optically bright ones, and the entire sample of BALQSOs are intrinsically X-ray weak when compared to normal active galactic nuclei (AGNs). Correcting for magnification of X-ray emission via gravitational lensing by the central black hole viewed at large inclination angles makes these BALQSOs even more intrinsically X-ray weak. Finally, we estimate AGN kinetic feedback efficiencies of a few percent for an X-ray wind of 0.3c in high-ionization BALQSOs. Combined with energy carried by low-ionization BALQSOs and UV winds, the total kinetic energy in BALQSOs can be sufficient to provide AGN kinetic feedback required to explain the co-evolution between black holes and host galaxies.

  18. Percutaneous absorption of methimazole: an in vitro study of the absorption pharmacokinetics for two different vehicles.

    PubMed

    Hill, K E; Mills, P C; Jones, B R; Bolwell, C F; Aberdein, D; Chambers, J P

    2015-12-01

    The use of transdermal medications in cats has become popular in veterinary medicine due to the ease of administration compared to oral medication. However, the research to support systemic absorption of drugs applied to the pinna after transdermal administration in cats is limited. The aim of this study was to characterize the percutaneous absorption pharmacokinetics of methimazole in a lipophilic vehicle compared to methimazole in Pluronic(®) lecithin organogel (PLO) using a finite dose applied to feline ear skin in an in vitro Franz cell model. The two formulations of methimazole (10 mg) were applied to the inner stratum corneum of six pairs of feline ears. The receptor medium was sampled up to 30 h post-administration, and methimazole concentrations were measured using high-performance liquid chromatography (HPLC). Histological examination of all ears was undertaken as small differences in the thickness of ear skin may have contributed to inter-individual differences in methimazole absorption between six cats. Methimazole was absorbed more completely across the pinnal skin when administered in the lipophilic vehicle compared to administration in the PLO gel (P < 0.001).

  19. Invisible Active Galactic Nuclei. II. Radio Morphologies and Five New H i 21cm Absorption Line Detectors

    NASA Astrophysics Data System (ADS)

    Yan, Ting; Stocke, John T.; Darling, Jeremy; Momjian, Emmanuel; Sharma, Soniya; Kanekar, Nissim

    2016-03-01

    This is the second paper directed toward finding new highly redshifted atomic and molecular absorption lines at radio frequencies. To this end, we selected a sample of 80 candidates for obscured radio-loud active galactic nuclei (AGNs) and presented their basic optical/near-infrared (NIR) properties in Paper I. In this paper, we present both high-resolution radio continuum images for all of these sources and H i 21 cm absorption spectroscopy for a few selected sources in this sample. A-configuration 4.9 and 8.5 GHz Very Large Array continuum observations find that 52 sources are compact or have substantial compact components with size <0.″5 and flux densities >0.1 Jy at 4.9 GHz. The 36 most compact sources were then observed with the Very Long Baseline Array at 1.4 GHz. One definite and 10 candidate Compact Symmetric Objects (CSOs) are newly identified, which is a detection rate of CSOs ∼three times higher than the detection rate previously found in purely flux-limited samples. Based on possessing compact components with high flux densities, 60 of these sources are good candidates for absorption-line searches. Twenty-seven sources were observed for H i 21 cm absorption at their photometric or spectroscopic redshifts with only six detections (five definite and one tentative). However, five of these were from a small subset of six CSOs with pure galaxy optical/NIR spectra (i.e., any AGN emission is obscured) and for which accurate spectroscopic redshifts place the redshifted 21 cm line in a radio frequency intereference (RFI)-free spectral “window” (i.e., the percentage of H i 21 cm absorption-line detections could be as high as ∼90% in this sample). It is likely that the presence of ubiquitous RFI and the absence of accurate spectroscopic redshifts preclude H i detections in similar sources (only 1 detection out of the remaining 22 sources observed, 13 of which have only photometric redshifts); that is, H i absorption may well be present but is masked by

  20. Study report on a double isotope method of calcium absorption

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Some of the pros and cons of three methods to study gastrointestinal calcium absorption are briefly discussed. The methods are: (1) a balance study; (2) a single isotope method; and (3) a double isotope method. A procedure for the double isotope method is also included.

  1. Real-time trace gas sensor using a multimode diode laser and multiple-line integrated cavity enhanced absorption spectroscopy.

    PubMed

    Karpf, Andreas; Rao, Gottipaty N

    2015-07-01

    We describe and demonstrate a highly sensitive trace gas sensor based on a simplified design that is capable of measuring sub-ppb concentrations of NO2 in tens of milliseconds. The sensor makes use of a relatively inexpensive Fabry-Perot diode laser to conduct off-axis cavity enhanced spectroscopy. The broad frequency range of a multimode Fabry-Perot diode laser spans a large number of absorption lines, thereby removing the need for a single-frequency tunable laser source. The use of cavity enhanced absorption spectroscopy enhances the sensitivity of the sensor by providing a pathlength on the order of 1 km in a small volume. Off-axis alignment excites a large number of cavity modes simultaneously, thereby reducing the sensor's susceptibility to vibration. Multiple-line integrated absorption spectroscopy (where one integrates the absorption spectra over a large number of rovibronic transitions of the molecular species) further improves the sensitivity of detection. Relatively high laser power (∼400  mW) is used to compensate for the low coupling efficiency of a broad linewidth laser to the optical cavity. The approach was demonstrated using a 407 nm diode laser to detect trace quantities of NO2 in zero air. Sensitivities of 750 ppt, 110 ppt, and 65 ppt were achieved using integration times of 50 ms, 5 s, and 20 s respectively.

  2. Searching for narrow absorption and emission lines in XMM-Newton spectra of gamma-ray bursts

    NASA Astrophysics Data System (ADS)

    Campana, S.; Braito, V.; D'Avanzo, P.; Ghirlanda, G.; Melandri, A.; Pescalli, A.; Salafia, O. S.; Salvaterra, R.; Tagliaferri, G.; Vergani, S. D.

    2016-08-01

    We present the results of a spectroscopic search for narrow emission and absorption features in the X-ray spectra of long gamma-ray burst (GRB) afterglows. Using XMM-Newton data, both EPIC and RGS spectra, of six bright (fluence > 10-7 erg cm-2) and relatively nearby (z = 0.54-1.41) GRBs, we performed a blind search for emission or absorption lines that could be related to a high cloud density or metal-rich gas in the environ close to the GRBs. We detected five emission features in four of the six GRBs with an overall statistical significance, assessed through Monte Carlo simulations, of ≲ 3.0σ. Most of the lines are detected around the observed energy of the oxygen edge at ~ 0.5 keV, suggesting that they are not related to the GRB environment but are most likely of Galactic origin. No significant absorption features were detected. A spectral fitting with a free Galactic column density (NH) testing different models for the Galactic absorption confirms this origin because we found an indication of an excess of Galactic NH in these four GRBs with respect to the tabulated values.

  3. Laser absorption spectroscopy of water vapor confined in nanoporous alumina: wall collision line broadening and gas diffusion dynamics.

    PubMed

    Svensson, Tomas; Lewander, Märta; Svanberg, Sune

    2010-08-01

    We demonstrate high-resolution tunable diode laser absorption spectroscopy (TDLAS) of water vapor confined in nanoporous alumina. Strong multiple light scattering results in long photon pathlengths (1 m through a 6 mm sample). We report on strong line broadening due to frequent wall collisions (gas-surface interactions). For the water vapor line at 935.685 nm, the HWHM of confined molecules are about 4.3 GHz as compared to 2.9 GHz for free molecules (atmospheric pressure). Gas diffusion is also investigated, and in contrast to molecular oxygen (that moves rapidly in and out of the alumina), the exchange of water vapor is found very slow.

  4. Broad Balmer Absorption Line Variability: Evidence of Gas Transverse Motion in the QSO SDSS J125942.80+121312.6

    NASA Astrophysics Data System (ADS)

    Shi, Xiheng; Zhou, Hongyan; Shu, Xinwen; Zhang, Shaohua; Ji, Tuo; Pan, Xiang; Sun, Luming; Zhao, Wen; Hao, Lei

    2016-03-01

    We report on the discovery of broad Balmer absorption lines variability in the QSO SDSS J125942.80+121312.6, based on the optical and near-infrared spectra taken from the SDSS-I, SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), and TripleSpec observations over a timescale of 5.8 years in the QSO's rest-frame. The blueshifted absorption profile of Hβ shows a variation of more than 5σ at a high velocity portion (\\gt 3000 {km} {{{s}}}-1) of the trough. We perform a detailed analysis for the physical conditions of the absorber using Balmer lines as well as metastable He i and optical Fe ii absorptions (λ4233 from b4P5/2 level and λ5169 from a6S5/2) at the same velocity. These Fe ii lines are identified in the QSO spectra for the first time. According to the photoionization simulations, we estimate a gas density of n({{H}})≈ {10}9.1 {{cm}}-3 and a column density of {N}{col}({{H}})≈ {10}23 {{cm}}-2 for the BOSS data, but the model fails to predict the variations of ionic column densities between the SDSS and BOSS observations if changes in ionizing flux are assumed. We thus propose transverse motion of the absorbing gas being the cause of the observed broad Balmer absorption line variability. In fact, we find that the changes in covering factors of the absorber can well-reproduce all of the observed variations. The absorber is estimated ∼0.94 pc away from the central engine, which is where the outflow likely experiences deceleration due to the collision with the surrounding medium. This scheme is consistent with the argument that LoBAL QSOs may represent the transition from obscured star-forming galaxies to classic QSOs.

  5. Recovery of acetylene absorption line profile basing on tunable diode laser spectroscopy with intensity modulation and photoacoustic spectroscopy

    NASA Astrophysics Data System (ADS)

    Li, Li; Thursby, Graham; Stewart, George; Arsad, Norhana; Uttamchandani, Deepak; Culshaw, Brian; Wang, Yiding

    2010-04-01

    A novel and direct absorption line recovery technique based on tunable diode laser spectroscopy with intensity modulation is presented. Photoacoustic spectroscopy is applied for high sensitivity, zero background and efficient acoustic enhancement at a low modulation frequency. A micro-electromechanical systems (MEMS) mirror driven by an electrothermal actuator is used for generating laser intensity modulation (without wavelength modulation) through the external reflection. The MEMS mirror with 10μm thick structure material layer and 100nm thick gold coating is formed as a circular mirror of 2mm diameter attached to an electrothermal actuator and is fabricated on a chip that is wire-bonded and placed on a PCB holder. Low modulation frequency is adopted (since the resonant frequencies of the photoacoustic gas cell and the electrothermal actuator are different) and intrinsic high signal amplitude characteristics in low frequency region achieved from measured frequency responses for the MEMS mirror and the gas cell. Based on the property of photoacoustic spectroscopy and Beer's law that detectable sensitivity is a function of input laser intensity in the case of constant gas concentration and laser path length, a Keopsys erbium doped fibre amplifier (EDFA) with opto-communication C band and high output power up to 1W is chosen to increase the laser power. High modulation depth is achieved through adjusting the MEMS mirror's reflection position and driving voltage. In order to scan through the target gas absorption line, the temperature swept method is adopted for the tunable distributed feed-back (DFB) diode laser working at 1535nm that accesses the near-infrared vibration-rotation spectrum of acetylene. The profile of acetylene P17 absorption line at 1535.39nm is recovered ideally for ~100 parts-per-million (ppm) acetylene balanced by nitrogen. The experimental signal to noise ratio (SNR) of absorption line recovery for 500mW laser power was ~80 and hence the

  6. Hydrogen Balmer beta: The separation between line peaks for plasma electron density diagnostics and self-absorption test

    NASA Astrophysics Data System (ADS)

    Ivković, Milivoje; Konjević, Nikola; Pavlović, Zoran

    2015-03-01

    We propose a diagnostic technique for the measurement of plasma electron number density, Ne, based on the wavelength separation between peaks, ΔλPS, of hydrogen Balmer beta line, Hβ. In favor of the proposed diagnostic technique we demonstrate high sensitivity of ΔλPS on Ne and low sensitivity on plasma elementary processes and plasma parameters that may distort the line profile. These properties of ΔλPS enable reliable Ne plasma diagnostics in the presence of considerable self-absorption. On the basis of available theoretical data tables for the Hβ line profiles, simple Ne=f(ΔλPS) formulas are proposed. Their validity is experimentally confirmed in a low initial pressure pulsed discharge for the Ne range of (0.2-7)*1023 m-3. The agreement of the proposed formulas with another diagnostic technique is well within 10%. In addition, the difference in Ne values obtained from peak separation and from the Hβ line width is successfully used as a self-absorption test for line profile.

  7. In vivo studies of biotin absorption in distal rat intestine

    SciTech Connect

    Bowman, B.B.; Rosenberg, I.H.

    1986-03-01

    The authors have extended their previous studies of biotin absorption in rat proximal jejunum (PJ) to examine biotin absorptive capacity of rat ileum (I) and proximal colon (PC) using in vivo intestinal loop technique. Intestinal loops (2.5 cm) were filled with 0.3 ml of solution containing (/sup 3/H)-biotin and (/sup 14/C)-inulin in phosphate buffer, pH 6.5. Biotin absorption was determined on the basis of luminal biotin disappearance after correction for inulin recovery and averaged (pmol/loop-10 min; X +/- SEM). In related experiments, 5-cm loops of PJ, distal I (DI), or PC were filled with 0.5 ml of solution of similar composition (1.0 ..mu..M biotin). The abdominal cavity was closed and the rats were allowed to recover from anesthesia, then sacrificed 3 hr after injection. Biotin absorption averaged 96.2% (PJ), 93.2% (DI), and 25.8% (PC) of the dose administered. These differences were reflected in the radioactive biotin content of plasma and intestinal loop, kidney, and liver. These data demonstrate significant biotin absorption in rat DI and PC, as required if the intestinal microflora are to be considered as a source of biotin for the host.

  8. Theoretical study on absorption and emission spectra of adenine analogues.

    PubMed

    Liu, Hongxia; Song, Qixia; Yang, Yan; Li, Yan; Wang, Haijun

    2014-04-01

    Fluorescent nucleoside analogues have attracted much attention in studying the structure and dynamics of nucleic acids in recent years. In the present work, we use theoretical calculations to investigate the structural and optical properties of four adenine analogues (termed as A1, A2, A3, and A4), and also consider the effects of aqueous solution and base pairing. The results show that the fluorescent adenine analogues can pair with thymine to form stable H-bonded WC base pairs. The excited geometries of both adenine analogues and WC base pairs are similar to the ground geometries. The absorption and emission maxima of adenine analogues are greatly red shifted compared with nature adenine, the oscillator strengths of A1 and A2 are stronger than A3 and A4 in both absorption and emission spectra. The calculated low-energy peaks in the absorption spectra are in good agreement with the experimental data. In general, the aqueous solution and base pairing can slightly red-shift both the absorption and emission maxima, and can increase the oscillator strengths of absorption spectra, but significantly decrease the oscillator strengths of A3 in emission spectra.

  9. Weak hard X-ray emission from broad absorption line quasars: evidence for intrinsic X-ray weakness

    SciTech Connect

    Luo, B.; Brandt, W. N.; Scott, A. E.; Alexander, D. M.; Gandhi, P.; Stern, D.; Teng, S. H.; Arévalo, P.; Bauer, F. E.; Boggs, S. E.; Craig, W. W.; Christensen, F. E.; Comastri, A.; Farrah, D.; Hailey, C. J.; Harrison, F. A.; Koss, M.; Ogle, P.; Puccetti, S.; Saez, C.; and others

    2014-10-10

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

  10. NEW PERSPECTIVE ON GALAXY OUTFLOWS FROM THE FIRST DETECTION OF BOTH INTRINSIC AND TRAVERSE METAL-LINE ABSORPTION

    SciTech Connect

    Kacprzak, Glenn G.; Cooke, Jeff; Martin, Crystal L.; Ho, Stephanie H.; Bouché, Nicolas; LeReun, Audrey; Schroetter, Ilane; Churchill, Christopher W.; Klimek, Elizabeth

    2014-09-01

    We present the first observation of a galaxy (z = 0.2) that exhibits metal-line absorption back-illuminated by the galaxy (down-the-barrel) and transversely by a background quasar at a projected distance of 58 kpc. Both absorption systems, traced by Mg II, are blueshifted relative to the galaxy systemic velocity. The quasar sight line, which resides almost directly along the projected minor axis of the galaxy, probes Mg I and Mg II absorption obtained from the Keck/Low Resolution Imaging Spectrometer as well as Lyα, Si II, and Si III absorption obtained from the Hubble Space Telescope/Cosmic Origins Spectrograph. For the first time, we combine two independent models used to quantify the outflow properties for down-the-barrel and transverse absorption. We find that the modeled down-the-barrel deprojected outflow velocities range between V {sub dtb} = 45-255 km s{sup –1}. The transverse bi-conical outflow model, assuming constant-velocity flows perpendicular to the disk, requires wind velocities V {sub outflow} = 40-80 km s{sup –1} to reproduce the transverse Mg II absorption kinematics, which is consistent with the range of V {sub dtb}. The galaxy has a metallicity, derived from Hα and N II, of [O/H] = –0.21 ± 0.08, whereas the transverse absorption has [X/H] = –1.12 ± 0.02. The galaxy star formation rate is constrained between 4.6-15 M {sub ☉} yr{sup –1} while the estimated outflow rate ranges between 1.6-4.2 M {sub ☉} yr{sup –1} and yields a wind loading factor ranging between 0.1-0.9. The galaxy and gas metallicities, the galaxy-quasar sight-line geometry, and the down-the-barrel and transverse modeled outflow velocities collectively suggest that the transverse gas originates from ongoing outflowing material from the galaxy. The ∼1 dex decrease in metallicity from the base of the outflow to the outer halo suggests metal dilution of the gas by the time it reached 58 kpc.

  11. New Perspective on Galaxy Outflows from the First Detection of Both Intrinsic and Traverse Metal-line Absorption

    NASA Astrophysics Data System (ADS)

    Kacprzak, Glenn G.; Martin, Crystal L.; Bouché, Nicolas; Churchill, Christopher W.; Cooke, Jeff; LeReun, Audrey; Schroetter, Ilane; Ho, Stephanie H.; Klimek, Elizabeth

    2014-09-01

    We present the first observation of a galaxy (z = 0.2) that exhibits metal-line absorption back-illuminated by the galaxy (down-the-barrel) and transversely by a background quasar at a projected distance of 58 kpc. Both absorption systems, traced by Mg II, are blueshifted relative to the galaxy systemic velocity. The quasar sight line, which resides almost directly along the projected minor axis of the galaxy, probes Mg I and Mg II absorption obtained from the Keck/Low Resolution Imaging Spectrometer as well as Lyα, Si II, and Si III absorption obtained from the Hubble Space Telescope/Cosmic Origins Spectrograph. For the first time, we combine two independent models used to quantify the outflow properties for down-the-barrel and transverse absorption. We find that the modeled down-the-barrel deprojected outflow velocities range between V dtb = 45-255 km s-1. The transverse bi-conical outflow model, assuming constant-velocity flows perpendicular to the disk, requires wind velocities V outflow = 40-80 km s-1 to reproduce the transverse Mg II absorption kinematics, which is consistent with the range of V dtb. The galaxy has a metallicity, derived from Hα and N II, of [O/H] = -0.21 ± 0.08, whereas the transverse absorption has [X/H] = -1.12 ± 0.02. The galaxy star formation rate is constrained between 4.6-15 M ⊙ yr-1 while the estimated outflow rate ranges between 1.6-4.2 M ⊙ yr-1 and yields a wind loading factor ranging between 0.1-0.9. The galaxy and gas metallicities, the galaxy-quasar sight-line geometry, and the down-the-barrel and transverse modeled outflow velocities collectively suggest that the transverse gas originates from ongoing outflowing material from the galaxy. The ~1 dex decrease in metallicity from the base of the outflow to the outer halo suggests metal dilution of the gas by the time it reached 58 kpc.

  12. Determination of vibration-rotation lines intensities from absorption Fourier spectra

    NASA Technical Reports Server (NTRS)

    Mandin, J. Y.

    1979-01-01

    The method presented allows the line intensities to be calculated from either their equivalent widths, heights, or quantities deduced from spectra obtained by Fourier spectrometry. This method has proven its effectiveness in measuring intensities of 60 lines of the molecule H2O with a precision of 10%. However, this method cannot be applied to isolated lines.

  13. Distances to diffuse interstellar clouds from IRAS measurements and observations of optical absorption lines

    NASA Technical Reports Server (NTRS)

    Federman, S. R.; Strom, C. J.; Good, J. C.

    1991-01-01

    Distances to diffuse interstellar clouds were determined from the amount of ultraviolet radiation that penetrates into the cloud and that arises from a nearby B star. The environment around 67 Ophiuchi, 20 Aquilae, kappa Aquilae, and 9 Cephei were studied. The intensities at 60 and 100 micron, as measured by IRAS, were used to derive dust temperatures for the clouds. Enhanced dust temperatures would indicate an influence of the star's radiation field on a cloud. Observation of molecular absorption were compared to the results of simplified chemical models in order to search for enhanced photodissociation that is caused by the star. Enhanced dust temperatures were observed for clouds in the vicinities of 20 Aql, kappa Agl, and 9 Cep. The range of the star's influence was found to be typically 1-5 pc. On the other hand, chemical analyses of the molecular data, which pertain to foreground gas, did not reveal the presence of enhanced dissociative flux from the sample of stars. Thus, upper limits were derived for the distances from the sun to the foreground material.

  14. The dependence of C IV broad absorption line properties on accompanying Si IV and Al III absorption: relating quasar-wind ionization levels, kinematics, and column densities

    SciTech Connect

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

    2014-08-20

    We consider how the profile and multi-year variability properties of a large sample of C IV Broad Absorption Line (BAL) troughs change when BALs from Si IV and/or Al III are present at corresponding velocities, indicating that the line of sight intercepts at least some lower ionization gas. We derive a number of observational results for C IV BALs separated according to the presence or absence of accompanying lower ionization transitions, including measurements of composite profile shapes, equivalent width (EW), characteristic velocities, composite variation profiles, and EW variability. We also measure the correlations between EW and fractional-EW variability for C IV, Si IV, and Al III. Our measurements reveal the basic correlated changes between ionization level, kinematics, and column density expected in accretion-disk wind models; e.g., lines of sight including lower ionization material generally show deeper and broader C IV troughs that have smaller minimum velocities and that are less variable. Many C IV BALs with no accompanying Si IV or Al III BALs may have only mild or no saturation.

  15. Interactions of praseodymium and neodymium with nucleosides and nucleotides: absorption difference and comparative absorption spectral study.

    PubMed

    Misra, S N; Anjaiah, K; Joseph, G; Abdi, S H

    1992-02-01

    The interactions of praseodymium(III) and neodymium(III) with nucleosides and nucleotides have been studied in different stoichiometry in water and water-DMF mixtures by employing absorption difference and comparative absorption spectrophotometry. The 4f-4f bands were analysed by linear curve analysis followed by gaussian curve analysis, and various spectral parameters were computed, using partial and multiple regression method. The magnitude of changes in both energy interaction and intensity were used to explore the degree of outer and inner sphere coordination, incidence of covalency and the extent of metal 4f-orbital involvement in chemical bonding. Crystalline complexes of the type [Ln(nucleotide)2(H2O)2]- (where nucleotide--GMP or IMP) were characterized by IR, 1H NMR, 31P NMR data. These studies indicated that the binding of the nucleotide is through phosphate oxygen in a bidentate manner and the complexes undergo substantial ionisation in aqueous medium, thereby supporting the observed weak 4f-4f bands and lower values for nephelauxetic effect (1-beta), bonding (b) and covalency (delta) parameters derived from coulombic and spin orbit interaction parameters.

  16. 1E 0104.2 + 3153 - A broad absorption-line QSO viewed through a giant elliptical galaxy

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  17. X-ray absorption lines suggest matter infalling onto the central black-hole of Mrk 509

    NASA Astrophysics Data System (ADS)

    Dadina, M.; Cappi, M.; Malaguti, G.; Ponti, G.; de Rosa, A.

    2005-11-01

    Evidence for both red- and blue-shifted absorption lines due to ionized Fe in the X-ray spectrum of the Seyfert 1 galaxy Mrk 509 is reported. These features appear to be transient on time-scales as short as ~20 ks, and have been observed with two different satellites, BeppoSAX and XMM-Newton. The red- and blue-shifted lines are found at E˜5.5 keV and ~8.1-8.3 keV (rest-frame), respectively. The first is seen in one out of six BeppoSAX observations, the latter is seen by both satellites. Under the assumption that the absorption is due to either H- or He-like Iron, the implied velocities for the absorbing matter are v˜0.15-0.2 c, in both outward and inward directions. An alternative explanation in terms of gravitational red-shift for the ~5.5 keV line cannot be ruled out with the current data. We argue, however, that the temporal patterns and sporadic nature of the lines are more easily reconciled with models that predict important radial motions close to the central black hole, such as the "aborted jet" model, the "thundercloud" model, or magneto-hydrodynamical models of jets and accretion-disks.

  18. On-line preconcentration and determination of chromium in parenteral solutions by flow injection-flame atomic absorption spectrometry.

    PubMed

    Wuilloud, Gustavo M; Wuilloud, Rodolfo G; de Wuilloud, Jorgelina C A; Olsina, Roberto A; Martinez, Luis D

    2003-02-01

    An on-line chromium preconcentration and determination system implemented with flame atomic absorption spectrometry (FAAS) associated to flow injection (FI) was studied. For the retention of chromium, 4-(2-Thiazolylazo)-resorcinol (TAR) and Amberlite XAD-16 were used, at pH 5.0. The Cr-TAR complex was removed from the micro-column with ethanol. An enrichment factor of 50 was obtained for the preconcentration of 50 ml of sample solution. The detection limit value for the preconcentration of 50 ml of aqueous solution of Cr was 20 ng l(-1). The precision for ten replicate determinations at the 5 microg l(-1) Cr levels was 2.9% relative standard deviation (RSD), calculated from the peak heights obtained. The calibration graph using the preconcentration system for chromium was linear with a correlation coefficient of 0.9997 at levels near the detection limits up to at least 100 microg l(-1). The method was successfully applied to the determination of chromium in parenteral solution samples.

  19. The CO2 absorption spectrum in the 2.3 μm transparency window by high sensitivity CRDS: (I) Rovibrational lines

    NASA Astrophysics Data System (ADS)

    Vasilchenko, S.; Konefal, M.; Mondelain, D.; Kassi, S.; Čermák, P.; Tashkun, S. A.; Perevalov, V. I.; Campargue, A.

    2016-11-01

    The absorption of carbon dioxide is very weak near 2.3 μm which makes this transparency window of particular interest for the study of Venus' lower atmosphere. As a consequence of the weakness of the transitions located in this region, previous experimental data are very scarce and spectroscopic databases provide calculated line lists which should be tested and validated by experiment. In this work, we use the Cavity Ring Down Spectroscopy (CRDS) technique for a high sensitivity characterization of the CO2 absorption spectrum in two spectral intervals of the 2.3 μm window: 4248-4257 and 4295-4380 cm-1 which were accessed using a Distributed Feed Back (DFB) diode laser and a Vertical External Cavity Surface Emitting Laser (VECSEL) as light sources, respectively. The achieved sensitivity (noise equivalent absorption, αmin, on the order of 5×10-10 cm-1) allowed detecting numerous new transitions with intensity values down to 5×10-30 cm/molecule. The rovibrational assignments were performed by comparison with available theoretical line lists in particular those obtained at IAO Tomsk using the global effective operator approach. Hot bands of the main isotopologue and 16O12C18O bands were found to be missing in the HITRAN database while they contribute importantly to the absorption in the region. Additional CRDS spectra of a CO2 sample highly enriched in 18O were recorded in order to improve the spectroscopy of this isotopologue. As a result about 700 lines of 16O12C18O, 16O12C17O, 17O12C18O, 12C18O2 and 13C18O2 were newly measured. The status of the different databases (HITRAN, CDSD, variational calculations) in the important 2.3 μm transparency window is discussed. Possible improvements to correct evidenced deficiencies are suggested.

  20. Pulsed Airborne Lidar Measurements of Atmospheric CO2 Column Absorption and Line Shapes from 3-13 km Altitudes

    NASA Technical Reports Server (NTRS)

    Abshire, James; Riris, Haris; Allan, Graham; Weaver, Clark; Mao, Jianping; Sun, Xiaoli; Hasselbrack, William

    2010-01-01

    We have developed a pulsed lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's planned ASCENDS space mission. Our technique uses two pulsed laser transmitters allowing simultaneous measurement of a CO2 absorption line in the 1570 nm band, O2 extinction in the Oxygen A-band and surface height and backscatter. The lidar measures the energy and time of flight of the laser echoes reflected from the atmosphere and surface. The lasers are rapidly and precisely stepped in wavelength across the CO2 line and an O2 line region during the measurement. The direct detection receiver uses a telescope and photon counting detectors, and measures the background light and energies of the laser echoes from the surface along with scattering from any aerosols in the path. The gas extinction and column densities for the CO2 and O2 gases are estimated from the ratio of the on- and off- line signals via the DIAL technique. Time gating is used to isolate the laser echo signals from the surface, and to reject laser photons scattered in the atmosphere. The time of flight of the laser pulses are also used to estimate the height of the scattering surface and to identify cases of mixed cloud and ground scattering. We have developed an airborne lidar to demonstrate the CO2 measurement from the NASA Glenn Lear-25 aircraft. The airborne lidar steps the pulsed laser's wavelength across the selected CO2 line with 20 steps per scan. The line scan rate is 450 Hz, the laser pulse widths are 1 usec, and laser pulse energy is 24 uJ. The time resolved laser backscatter is collected by a 20 cm telescope, detected by a photomultiplier and is recorded by a photon counting system. We made initial airborne measurements on flights during fall 2008. Laser backscatter and absorption measurements were made over a variety of land and water surfaces and through thin clouds. The atmospheric CO2 column measurements using the 1572.33 nm CO2 lines. Two flights were made above the

  1. Simultaneous assessment of cholesterol absorption and synthesis in humans using on-line gas chromatography/ combustion and gas chromatography/pyrolysis/isotope-ratio mass spectrometry.

    PubMed

    Gremaud, G; Piguet, C; Baumgartner, M; Pouteau, E; Decarli, B; Berger, A; Fay, L B

    2001-01-01

    A number of dietary components and drugs are known to inhibit the absorption of dietary and biliary cholesterol, but at the same time can compensate by increasing cholesterol synthesis. It is, therefore, necessary to have a convenient and accurate method to assess both parameters simultaneously. Hence, we validated such a method in humans using on-line gas chromatography(GC)/combustion and GC/pyrolysis/isotope-ratio mass spectrometry (IRMS). Cholesterol absorption was measured using the ratio of [(13)C]cholesterol (injected intravenously) to [(18)O]cholesterol (administered orally). Simultaneously, cholesterol synthesis was measured using the deuterium incorporation method. Our methodology was applied to 12 mildly hypercholesterolemic men that were given a diet providing 2685 +/- 178 Kcal/day (mean +/- SD) and 255 +/- 8 mg cholesterol per day. Cholesterol fractional synthesis rates ranged from 5.0 to 10.5% pool/day and averaged 7.36% +/- 1.78% pool/day (668 +/- 133 mg/day). Cholesterol absorption ranged from 36.5-79.9% with an average value of 50.8 +/- 15.4%. These values are in agreement with already known data obtained with mildly hypercholesterolemic Caucasian males placed on a diet similar to the one used for this study. However, our combined IRMS method has the advantage over existing methods that it enables simultaneous measurement of cholesterol absorption and synthesis in humans, and is therefore an important research tool for studying the impact of dietary treatments on cholesterol parameters.

  2. Electron paramagnetic resonance and optical absorption spectral studies on chalcocite

    NASA Astrophysics Data System (ADS)

    Reddy, S. Lakshmi; Fayazuddin, Md.; Frost, Ray L.; Endo, Tamio

    2007-11-01

    A chalcocite mineral sample of Shaha, Congo is used in the present study. An electron paramagnetic resonance (EPR) study on powdered sample confirms the presence of Mn(II), Fe(III) and Cu(II). Optical absorption spectrum indicates that Fe(III) impurity is present in octahedral structure whereas Cu(II) is present in rhombically distorted octahedral environment. Mid-infrared results are due to water and sulphate fundamentals.

  3. Electron paramagnetic resonance and optical absorption spectral studies on chalcocite.

    PubMed

    Reddy, S Lakshmi; Fayazuddin, Md; Frost, Ray L; Endo, Tamio

    2007-11-01

    A chalcocite mineral sample of Shaha, Congo is used in the present study. An electron paramagnetic resonance (EPR) study on powdered sample confirms the presence of Mn(II), Fe(III) and Cu(II). Optical absorption spectrum indicates that Fe(III) impurity is present in octahedral structure whereas Cu(II) is present in rhombically distorted octahedral environment. Mid-infrared results are due to water and sulphate fundamentals. PMID:17324611

  4. The Fundamental Quadrupole Band of (14)N2: Line Positions from High-Resolution Stratospheric Solar Absorption Spectra

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Zander, R.; Goldman, A.; Murcray, F. J.; Murcray, D. G.; Grunson, M. R.; Farmer, C. B.

    1991-01-01

    The purpose of this note is to report accurate measurements of the positions of O- and S-branch lines of the (1-0) vibration-rotation quadrupole band of molecular nitrogen ((14)N2) and improved Dunham coefficients derived from a simultaneous least-squares analysis of these measurements and selected infrared and far infrared data taken from the literature. The new measurements have been derived from stratospheric solar occultation spectra recorded with Fourier transform spectrometer (FTS) instruments operated at unapodized spectral resolutions of 0.002 and 0.01 /cm. The motivation for the present investigation is the need for improved N2 line parameters for use in IR atmospheric remote sensing investigations. The S branch of the N2 (1-0) quadrupole band is ideal for calibrating the line-of-sight airmasses of atmospheric spectra since the strongest lines are well placed in an atmospheric window, their absorption is relatively insensitive to temperature and is moderately strong (typical line center depths of 10 to 50% in high-resolution ground-based solar spectra and in lower stratospheric solar occultation spectra), and the volume mixing ratio of nitrogen is constant in the atmosphere and well known. However, a recent investigation has'shown the need to improve the accuracies of the N2 fine positions, intensities, air-broadened half-widths, and their temperature dependences to fully exploit this calibration capability (1). The present investigation addresses the problem of improving the accuracy of the N2 line positions.

  5. Improved constraints on possible variation of physical constants from H i 21-cm and molecular QSO absorption lines

    NASA Astrophysics Data System (ADS)

    Murphy, M. T.; Webb, J. K.; Flambaum, V. V.; Drinkwater, M. J.; Combes, F.; Wiklind, T.

    2001-11-01

    Quasar (QSO) absorption spectra provide an extremely useful probe of possible cosmological variation in various physical constants. Comparison of Hi 21-cm absorption with corresponding molecular (rotational) absorption spectra allows us to constrain variation in [formmu2]y≡α2gp, where α is the fine-structure constant and gp is the proton g-factor. We analyse spectra of two QSOs, PKS 1413+135 and TXS 0218+357, and derive values of [formmu3]Δy/y at absorption redshifts of [formmu4]z=0.2467 and 0.6847 by simultaneous fitting of the Hi 21-cm and molecular lines. We find [formmu5]Δy/y=(-0.20+/-0.44)×10-5 and [formmu6]Δy/y=(-0.16+/-0.54)×10-5 respectively, indicating an insignificantly smaller y in the past. We compare our results with other constraints from the same two QSOs given recently by Drinkwater et al. and Carilli et al., and with our recent optical constraints, which indicated a smaller α at higher redshifts.

  6. Pulsed Airborne Lidar Measurements of Atmospheric CO2 Column Absorption and Line Shapes from 3-13 km Altitudes

    NASA Technical Reports Server (NTRS)

    Abshire, J. B.; Riris, H.; Allan, G. R.; Weaver, C.; Hasselbrack, W.; Sun, X.

    2009-01-01

    We have developed a lidar technique for measuring the tropospheric C02 concentrations as a candidate for NASA's planned ASCENDS mission. Our technique uses two pulsed laser transmitters allowing simultaneous measurement of a C02 absorption line in the 1570 nm band, 02 extinction in the Oxygen A-band and surface height and backscatter. The lidar measures the energy and time of flight of the laser echoes reflected from the atmosphere and surface. The lasers are stepped in wavelength across the C02 line and an 02 line region during the measurement. The receiver uses a telescope and photon counting detectors, and measures the background light and energies of the laser echoes from the surface along with scattering from any aerosols in the path. The gas extinction and column densities for the C02 and 02 gases are estimated from the ratio of the on- and off- line signals via the DIAL technique. Time gating is used to isolate the laser echo signals from the surface, and to reject laser photons scattered in the atmosphere. We have developed an airborne lidar to demonstrate the C02 measurement from the NASA Glenn Lear 25 aircraft. The airborne lidar steps the pulsed laser's wavelength across a selected C02 line with 20 steps per scan. The line scan rate is 450 Hz and laser pulse widths are I usec. The time resolved laser backscatter is collected by a 20 cm telescope, detected by a photomultiplier and is recorded by a photon counting system. We made initial airborne measurements on flights during October and December 2008. Laser backscatter and absorption measurements were made over a variety of land and water surfaces and through thin and broken clouds. Atmospheric C02 column measurements using the 1571.4, 1572.02 and 1572.33 nm C02 lines. Two flights were made above the DOE SGP ARM site at altitudes from 3-8 km. These nights were coordinated with DOE investigators who Hew an in-situ C02 sensor on a Cessna aircraft under the path. The increasing C02 line absorptions with

  7. Origins of optical absorption and emission lines in AlN

    SciTech Connect

    Yan, Qimin; Janotti, Anderson; Van de Walle, Chris G.; Scheffler, Matthias

    2014-09-15

    To aid the development of AlN-based optoelectronics, it is essential to identify the defects that cause unwanted light absorption and to minimize their impact. Using hybrid functional calculations, we investigate the role of native defects and their complexes with oxygen, a common impurity in AlN. We find that Al vacancies are the source of the absorption peak at 3.4 eV observed in irradiated samples and of the luminescence signals at 2.78 eV. The absorption peak at ∼4.0 eV and higher, and luminescence signals around 3.2 and 3.6 eV observed in AlN samples with high oxygen concentrations are attributed to complexes of Al vacancies and oxygen impurities. We also propose a transition involving Al and N vacancies and oxygen impurities that may be a cause of the absorption band peaked at 2.9 eV.

  8. SDSS J163459.82+204936.0: A Ringed Infrared-luminous Quasar with Outflows in Both Absorption and Emission Lines

    NASA Astrophysics Data System (ADS)

    Liu, Wen-Juan; Zhou, Hong-Yan; Jiang, Ning; Wu, Xufen; Lyu, Jianwei; Shi, Xiheng; Shu, Xinwen; Jiang, Peng; Ji, Tuo; Wang, Jian-Guo; Wang, Shu-Fen; Sun, Luming

    2016-05-01

    SDSS J163459.82+204936.0 is a local (z = 0.1293) infrared-luminous quasar with L IR = 1011.91 {L}ȯ . We present a detailed multiwavelength study of both the host galaxy and the nucleus. The host galaxy, appearing as an early-type galaxy in the optical images and spectra, demonstrates violent, obscured star formation activities with SFR ≈ 140 {M}ȯ yr‑1, estimated from either the polycyclic aromatic hydrocarbon emission or IR luminosity. The optical to NIR spectra exhibit a blueshifted narrow cuspy component in Hβ, He i λλ5876, 10830, and other emission lines consistently with an offset velocity of ≈900 {km} {{{s}}}-1, as well as additional blueshifting phenomena in high-ionization lines (e.g., a blueshifted broad component of He i λ10830 and the bulk blueshifting of [O iii]λ5007), while there exist blueshifted broad absorption lines (BALs) in Na i D and He i λλ3889, 10830, indicative of the active galactic nucleus outflows producing BALs and emission lines. Constrained mutually by the several BALs in the photoionization simulations with Cloudy, the physical properties of the absorption line outflow are derived as follows: density 104 < n H ≲ 105 cm‑3, ionization parameter 10‑1.3 ≲ U ≲ 10‑0.7 , and column density 1022.5 ≲ N H ≲ 1022.9 cm‑2, which are similar to those derived for the emission line outflows. This similarity suggests a common origin. Taking advantages of both the absorption lines and outflowing emission lines, we find that the outflow gas is located at a distance of ˜48–65 pc from the nucleus and that the kinetic luminosity of the outflow is 1044–1046 {erg} {{{s}}}-1. J1634+2049 has a off-centered galactic ring on the scale of ˜30 kpc that is proved to be formed by a recent head-on collision by a nearby galaxy for which we spectroscopically measure the redshift. Thus, this quasar is a valuable object in the transitional phase emerging out of dust enshrouding as depicted by the co-evolution scenario invoking galaxy

  9. SDSS J163459.82+204936.0: A Ringed Infrared-luminous Quasar with Outflows in Both Absorption and Emission Lines

    NASA Astrophysics Data System (ADS)

    Liu, Wen-Juan; Zhou, Hong-Yan; Jiang, Ning; Wu, Xufen; Lyu, Jianwei; Shi, Xiheng; Shu, Xinwen; Jiang, Peng; Ji, Tuo; Wang, Jian-Guo; Wang, Shu-Fen; Sun, Luming

    2016-05-01

    SDSS J163459.82+204936.0 is a local (z = 0.1293) infrared-luminous quasar with L IR = 1011.91 {L}⊙ . We present a detailed multiwavelength study of both the host galaxy and the nucleus. The host galaxy, appearing as an early-type galaxy in the optical images and spectra, demonstrates violent, obscured star formation activities with SFR ≈ 140 {M}⊙ yr-1, estimated from either the polycyclic aromatic hydrocarbon emission or IR luminosity. The optical to NIR spectra exhibit a blueshifted narrow cuspy component in Hβ, He i λλ5876, 10830, and other emission lines consistently with an offset velocity of ≈900 {km} {{{s}}}-1, as well as additional blueshifting phenomena in high-ionization lines (e.g., a blueshifted broad component of He i λ10830 and the bulk blueshifting of [O iii]λ5007), while there exist blueshifted broad absorption lines (BALs) in Na i D and He i λλ3889, 10830, indicative of the active galactic nucleus outflows producing BALs and emission lines. Constrained mutually by the several BALs in the photoionization simulations with Cloudy, the physical properties of the absorption line outflow are derived as follows: density 104 < n H ≲ 105 cm-3, ionization parameter 10-1.3 ≲ U ≲ 10-0.7 , and column density 1022.5 ≲ N H ≲ 1022.9 cm-2, which are similar to those derived for the emission line outflows. This similarity suggests a common origin. Taking advantages of both the absorption lines and outflowing emission lines, we find that the outflow gas is located at a distance of ˜48-65 pc from the nucleus and that the kinetic luminosity of the outflow is 1044-1046 {erg} {{{s}}}-1. J1634+2049 has a off-centered galactic ring on the scale of ˜30 kpc that is proved to be formed by a recent head-on collision by a nearby galaxy for which we spectroscopically measure the redshift. Thus, this quasar is a valuable object in the transitional phase emerging out of dust enshrouding as depicted by the co-evolution scenario invoking galaxy merger (or

  10. Interstellar absorption lines in the spectrum of sigma Sco using Copernicus observations

    NASA Technical Reports Server (NTRS)

    Allen, M. M.; Snow, T. P.

    1986-01-01

    Since the launch of Copernicus in 1972, studies have been made of the depletion of gas-phase elements onto dust grains. A few stars have been studied in detail, resulting in a standard depletion pattern which has since been used for comparison. Recent developments, however, have suggested that this standard pattern may need to be re-examined. Some weak, semi-forbidden lines were detected recently which may be able to resolve some of the ambiguities. Studies of single elements have shown that depletion of carbon and oxgyen are much smaller than previously determined. The high resolution ultraviolet spectral scans of sigma Sco were originally made in 1973, but have only recently been analyzed. All these stars are bright and moderately reddened. All four stars will be analyzed in detail, but sigma Sco is the first one completed. The data has broad coverage of ions, making these stars excellent candidates for determination of accurate depletions. A profile-fitting analysis was used rather than curves-of-growth in order to determine separate abundances and depletions in components separated by several km/sec.

  11. Laboratory studies at high resolution of the infrared absorption spectra of a number of gases found in planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Hunt, R. H.

    1983-01-01

    The infrared absorption spectra of a number of gases found in planetary atmospheres were studied at high resolution. Absorption line measurements which can be of value for the interpretation of planetary spectra in terms of molecular abundances and conditions in the planetary atmospheres were provided. The high resolution spectra have yielded measurements of individual vibration rotation line parameters including positions, strengths, pressure broadened widths and, where assignments were unknown, the temperature sensitivity of the strengths. Such information allows the determinations of the absorption of a given molecular gas under planetary conditions of temperature and pressure and at the same time it provides the data necessary if the spectra are to be understood in terms of basic molecular theory. Thus this work has included spectral analysis in the form of line assignments as well as fitting of the data to Hamiltonian models. Such fitting is very useful in that it helps to confirm and extend the assignments.

  12. An Extreme, Blueshifted Iron-Line Profile in the Narrow-Line Seyfert 1 PG 1402+261: An Edge-on Accretion Disk or Highly Ionized Absorption?

    NASA Astrophysics Data System (ADS)

    Reeves, J. N.; Porquet, D.; Turner, T. J.

    2004-11-01

    We report on a short XMM-Newton observation of the radio-quiet narrow-line Seyfert 1 galaxy PG 1402+261. The EPIC X-ray spectrum of PG 1402+261 shows a strong excess of counts between 6 and 9 keV in the rest frame. This feature can be modeled by an unusually strong (equivalent width 2 keV) and very broad (FWHM velocity of 110,000 km s-1) iron K-shell emission line. The line centroid energy at 7.3 keV appears blueshifted with respect to the iron Kα emission band between 6.4 and 6.97 keV, while the blue wing of the line extends to 9 keV in the quasar rest frame. The line profile can be fitted by reflection from the inner accretion disk, but an inclination angle of >60° is required to model the extreme blue wing of the line. Furthermore, the extreme strength of the line requires a geometry whereby the hard X-ray emission from PG 1402+261 above 2 keV is dominated by the pure-reflection component from the disk, while little or none of the direct hard power law is observed. Alternatively, the spectrum above 2 keV may be explained by an ionized absorber, if the column density is sufficiently high (NH>3×1023 cm-2) and if the matter is ionized enough to produce a deep (τ~1) iron K-shell absorption edge at 9 keV. This absorber could originate in a large column density, high-velocity outflow, perhaps similar to those that appear to be observed in several other high accretion rate active galactic nuclei. Further observations, especially at higher spectral resolution, are required to distinguish between the accretion disk reflection and outflow scenarios.

  13. Results of Monitoring the Dramatically Variable C IV Mini-Broad Absorption Line System in the Quasar HS 1603+3820

    NASA Astrophysics Data System (ADS)

    Misawa, Toru; Eracleous, Michael; Charlton, Jane C.; Kashikawa, Nobunari

    2007-05-01

    We present six new and two previously published high-resolution spectra of the quasar HS 1603+3820 (zem=2.542) taken over an interval of 4.2 yr (1.2 yr in the quasar rest frame). The observations were made with the High Dispersion Spectrograph on the Subaru telescope and the Medium Resolution Spectrograph on the Hobby-Eberly Telescope. The purpose was to study the narrow absorption lines (NALs). We use time variability and coverage fraction analysis to separate intrinsic absorption lines, which are physically related to the quasar, from intervening absorption lines. By fitting models to the line profiles, we derive the parameters of the respective absorbers as a function of time. Only the mini-BAL system at zabs~2.43 (vshift~9500 km s-1) shows both partial coverage and time variability, although two NAL systems possibly show evidence of partial coverage. We find that all the troughs of the mini-BAL system vary in concert and its total equivalent width variations resemble those of the coverage fraction. However, no other correlations are seen between the variations of different model parameters. Thus, the observed variations cannot be reproduced by a simple change of ionization state or by motion of a homogeneous parcel of gas across the cylinder of sight. We propose that the observed variations are a result of rapid continuum fluctuations, coupled with coverage fraction fluctuations caused by a clumpy screen of variable optical depth located between the continuum source and the mini-BAL gas. An alternative explanation is that the observed partial coverage signature is the result of scattering of continuum photons around the absorber, thus the equivalent width of the mini-BAL can vary as the intensity of the scattered continuum changes. Based on data collected at the Subaru telescope, which is operated by the National Astronomical Observatory of Japan.

  14. Further constraints on variation of the fine-structure constant from alkali-doublet QSO absorption lines

    NASA Astrophysics Data System (ADS)

    Murphy, M. T.; Webb, J. K.; Flambaum, V. V.; Prochaska, J. X.; Wolfe, A. M.

    2001-11-01

    Comparison of quasar (QSO) absorption-line spectra with laboratory spectra provides a precise probe for variability of the fine-structure constant, α, over cosmological time-scales. We constrain variation in α in 21 Keck/HIRES Siiv absorption systems using the alkali-doublet (AD) method in which changes in α are related to changes in the doublet spacing. The precision obtained with the AD method has been increased by a factor of 3: Δα/α=(-0.5+/-1.3)×10-5. We also analyse potential systematic errors in this result. Finally, we compare the AD method with the many-multiplet method, which has achieved an order of magnitude greater precision, and we discuss the future of the AD method.

  15. Possible evidence for a variable fine-structure constant from QSO absorption lines: motivations, analysis and results

    NASA Astrophysics Data System (ADS)

    Murphy, M. T.; Webb, J. K.; Flambaum, V. V.; Dzuba, V. A.; Churchill, C. W.; Prochaska, J. X.; Barrow, J. D.; Wolfe, A. M.

    2001-11-01

    An experimental search for variation in the fundamental coupling constants is strongly motivated by modern high-energy physics theories. Comparison of quasar (QSO) absorption-line spectra with laboratory spectra provides a sensitive probe for variability of the fine-structure constant, α, over cosmological time-scales. We have previously developed and applied a new method providing an order-of-magnitude gain in precision over previous optical astrophysical constraints. Here we extend that work by including new quasar spectra of damped Lyman-α absorption systems. We also reanalyse our previous lower-redshift data and confirm our initial results. The constraints on α come from simultaneous fitting of absorption lines of subsets of the following species: Mgi, Mgii, Alii, Aliii, Siii, Crii, Feii, Niii and Znii. We present a detailed description of our methods and results based on an analysis of 49 quasar absorption systems (towards 28 QSOs) covering the redshift range [formmu2]0.5

  16. Detection of High Velocity Absorption Components in the He I Lines of Eta Carinae near the Time of Periastron

    NASA Technical Reports Server (NTRS)

    Richardson, Noel D.; St-Jean, Lucas; Gull, Theodore R.; Madura, Thomas; Hillier, D. John; Teodoro, Mairan; Moffat, Anthony; Corcoran, Michael; Damineli, Augusto

    2014-01-01

    We have obtained a total of 58 high spectral resolution (R90,000) spectra of the massive binary star eta Carinae since 2012 in an effort to continue our orbital and long-term echelle monitoring of this extreme binary (Richardson et al. 2010, AJ, 139, 1534) with the CHIRON spectrograph on the CTIO 1.5 m telescope (Tokovinin et al. 2013, PASP, 125, 1336) in the 45507500A region. We have increased our monitoring efforts and observation frequency as the periastron event of 2014 has approached. We note that there were multiple epochs this year where we observe unusual absorption components in the P Cygni troughs of the He I triplet lines. In particular, we note high velocity absorption components related to the following epochs for the following lines: He I 4713: HJD 2456754- 2456795 (velocity -450 to -560 kms) He I 5876: HJD 2456791- 2456819 (velocity -690 to -800 kms) He I 7065: HJD 2456791- 2456810 (velocity -665 to -730 kms) Figures: Note that red indicates a high-velocity component noted above. He I 4713: http:www.astro.umontreal.carichardson4713.png He I 5876: http:www.astro.umontreal.carichardson5876.png He I 7065: http:www.astro.umontreal.carichardson7065.png These absorptions are likely related to the wind-wind collision region and bow shock, as suggested by the high-velocity absorption observed by Groh et al. (2010, AA, 519, 9) in the He I 10830 Atransition. In these cases, we suspect that we look along an arm of the shock cone and that we will see a fast absorption change from the other collision region shortly after periastron. We suspect that this is related to the multiple-components of the He II 4686 line that was noted by Walter (ATel6334), and is confirmed in our data. Further, high spectral resolution data are highly encouraged,especially for resolving powers greater than 50,000.These observations were obtained with the CTIO 1.5 m telescope, operated by the SMARTS Consortium, and were obtained through both SMARTS and NOAO programs 2012A-0216,2012B-0194

  17. The potential of UV-VIS-NIR absorption spectroscopy in glass studies

    NASA Astrophysics Data System (ADS)

    Meulebroeck, Wendy; Baert, Kitty; Ceglia, Andrea; Cosyns, Peter; Wouters, Hilde; Nys, Karin; Terryn, Herman; Thienpont, Hugo

    Absorption spectroscopy is the technique that measures the absorption of radiation as a function of wavelength, due to its interaction with the material. During a research project funded by our home university, we were able to investigate the possibilities of this technique to study ancient glasses. One of our main conclusions is that UV-VIS-NIR absorption spectroscopy is especially suited to characterize colored artifacts in terms of composition and furnace conditions. Moreover, for naturally colored window glasses, we have shown that this technique allows us to classify fragments based on differences in iron impurity levels. It is a semi-quantitative analysis tool that can be applied for a first-line analysis of (large) glass collections. Thanks to the commercial available portable instruments, these measurements can be performed at relative high speed and this in-situ if necessary. To illustrate the possibilities of this technique, we describe in this paper two case-studies. In a first test-case we analyze 63 naturally colored window glasses and demonstrate how groups with different iron concentrations can be identified by calculating the absorption edge position from the measured optical spectrum. In a second case-study 8 modern naturally colored and 31 intentionally colored Roman glass fragments are the point of focus. For these samples we first estimate which samples are potentially fabricated under the same furnace conditions. This is done based on the calculated color values. Finally we identify the type of applied colorants.

  18. Digital signal processor-based high-precision on-line Voigt lineshape fitting for direct absorption spectroscopy.

    PubMed

    Xu, Lijun; Liu, Chang; Zheng, Deyan; Cao, Zhang; Cai, Weiwei

    2014-12-01

    To realize on-line high-accuracy measurement in direct absorption spectroscopy (DAS), a system-on-chip, high-precision digital signal processor-based on-line Voigt lineshape fitting implementation is introduced in this paper. Given that the Voigt lineshape is determined by the Gauss full width at half maximum (FWHM) and Lorentz FWHM, a look-up table, which covers a range of combinations of both, is first built to achieve rapid and accurate calculation of Voigt lineshape. With the look-up table and raw absorbance data in hand, Gauss-Newton nonlinear fitting module is implemented to obtain the parameters including both the Gauss and Lorentz FWHMs, which can be used to calculate the integrated absorbance. To realize the proposed method in hardware, a digital signal processor (DSP) is adopted to fit the Voigt lineshape in a real-time DAS measurement system. In experiment, temperature and H2O concentration of a flat flame are recovered from the transitions of 7444.36 cm(-1) and 7185.6 cm(-1) by the DSP-based on-line Voigt lineshape fitting and on-line integral of the raw absorbance, respectively. The results show that the proposed method can not only fit the Voigt lineshape on-line but also improve the measurement accuracy compared with those obtained from the direct integral of the raw absorbance. PMID:25554273

  19. Digital signal processor-based high-precision on-line Voigt lineshape fitting for direct absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Xu, Lijun; Liu, Chang; Zheng, Deyan; Cao, Zhang; Cai, Weiwei

    2014-12-01

    To realize on-line high-accuracy measurement in direct absorption spectroscopy (DAS), a system-on-chip, high-precision digital signal processor-based on-line Voigt lineshape fitting implementation is introduced in this paper. Given that the Voigt lineshape is determined by the Gauss full width at half maximum (FWHM) and Lorentz FWHM, a look-up table, which covers a range of combinations of both, is first built to achieve rapid and accurate calculation of Voigt lineshape. With the look-up table and raw absorbance data in hand, Gauss-Newton nonlinear fitting module is implemented to obtain the parameters including both the Gauss and Lorentz FWHMs, which can be used to calculate the integrated absorbance. To realize the proposed method in hardware, a digital signal processor (DSP) is adopted to fit the Voigt lineshape in a real-time DAS measurement system. In experiment, temperature and H2O concentration of a flat flame are recovered from the transitions of 7444.36 cm-1 and 7185.6 cm-1 by the DSP-based on-line Voigt lineshape fitting and on-line integral of the raw absorbance, respectively. The results show that the proposed method can not only fit the Voigt lineshape on-line but also improve the measurement accuracy compared with those obtained from the direct integral of the raw absorbance.

  20. Time resolved metal line profile by near-ultraviolet tunable diode laser absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Vitelaru, C.; de Poucques, L.; Minea, T. M.; Popa, G.

    2011-03-01

    Pulsed systems are extensively used to produce active species such as atoms, radicals, excited states, etc. The tunable diode laser absorption spectroscopy (TD-LAS) is successfully used to quantify the density of absorbing species, but especially for stationary or slow changing systems. The time resolved-direct absorption profile (TR-DAP) measurement method by TD-LAS, with time resolution of μs is proposed here as an extension of the regular use of diode laser absorption spectroscopy. The spectral narrowness of laser diodes, especially in the blue range (˜0.01 pm), combined with the nanosecond fast trigger of the magnetron pulsed plasma and long trace recording on the oscilloscope (period of second scale) permit the detection of the sputtered titanium metal evolution in the afterglow (˜ms). TR-DAP method can follow the time-dependence of the temperature (Doppler profile) and the density (deduced from the absorbance) of any medium and heavy species in a pulsed system.

  1. Time-variability of the fine-structure constant expected from the Oklo constraint and the QSO absorption lines

    NASA Astrophysics Data System (ADS)

    Fujii, Yasunori

    2003-10-01

    The data from the QSO absorption lines indicating a nonzero time-variability of the fine-structure constant has been re-analyzed on the basis of a ``damped-oscillator'' fit, as motivated by the same type of behavior of a scalar field, dilaton, which mimics a cosmological constant to understand the accelerating universe. We find nearly as good fit to the latest data as the simple weighted mean. In this way, we offer a way to fit the more stringent result from the Oklo phenomenon, as well.

  2. A theoretical analysis of the X-ray cyclotron absorption lines of the isolated neutron star 1E1207.4-5209

    NASA Astrophysics Data System (ADS)

    Yuan, Ai-fang; Liu, Dang-bo; Chen, Lei; Ding, Li; You, Jun-hang

    2006-07-01

    As revealed by recent observations, in the X-ray continuum of the radio quiet isolated neutron star 1E1207.4-5209 there exist several equidistant absorption lines, and their energies are, respectively, 0.7, 1.4 and 2.1 keV. According to the theory of quantum cyclotron radiation under the quadrupolar approximation developed in recent years, we have clarified some existing doubts and affirmed that these lines are electron cyclotron absorption lines instead of proton cyclotron lines. Besides, the spatial orientation of the spin axis of this neutron star has been theoretically determined.

  3. Infrared heterodyne spectroscopy of astronomical and laboratory sources at 8.5 micron. [absorption line profiles of nitrogen oxide and black body emission from Moon and Mars

    NASA Technical Reports Server (NTRS)

    Mumma, M.; Kostiuk, T.; Cohen, S.; Buhl, D.; Vonthuna, P. C.

    1974-01-01

    The first infrared heterodyne spectrometer using tuneable semiconductor (PbSe) diode lasers has been constructed and was used near 8.5 micron to measure absorption line profiles of N2O in the laboratory and black body emission from the Moon and from Mars. Spectral information was recorded over a 200 MHz bandwidth using an 8-channel filter bank. The resolution was 25 MHz and the minimum detectable (black body) power was 1 x 10 to the minus 16th power watts for 8 minutes of integration. The results demonstrate the usefulness of heterodyne spectroscopy for the study of remote and local sources in the infrared.

  4. Beta-decay studies using total absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    GSI-TAS Collaboration; LUCRECIA-TAgS Collaboration; Algora, A.; Batist, L.; Borge, M. J. G.; Cano-Ott, D.; Collatz, R.; Courtin, S.; Dessagne, Ph; Fraile, L. M.; Gadea, A.; Gelletly, W.; Hellström, M.; Janas, Z.; Jungclaus, A.; Kirchner, R.; Karny, M.; Le Scornet, G.; Miehé, Ch; Maréchal, F.; Moroz, F.; Nácher, E.; Poirier, E.; Roeckl, E.; Rubio, B.; Rykaczewski, K.; Tain, J. L.; Tengblad, O.; Wittmann, V.

    2003-04-01

    . Beta-decay experiments are a primary source of information for nuclear-structure studies and at the same time complementary to in-beam investigations of nuclei far from stability. Although both types of experiment are mainly based on γ -ray spectroscopy, they face different experimental problems. The so-called Pandemonium effect is a critical problem in β -decay if we are to test theoretically calculated transition probabilities. In this contribution we will present a solution to this problem using total absorption spectroscopy methods. We will also present some examples of experiments carried out with the Total Absorption Spectrometer (TAS) at GSI an describe a new device LUCRECIA recently installed at CERN.

  5. Cognitive Distance, Absorptive Capacity and Group Rationality: A Simulation Study

    PubMed Central

    Curşeu, Petru Lucian; Krehel, Oleh; Evers, Joep H. M.; Muntean, Adrian

    2014-01-01

    We report the results of a simulation study in which we explore the joint effect of group absorptive capacity (as the average individual rationality of the group members) and cognitive distance (as the distance between the most rational group member and the rest of the group) on the emergence of collective rationality in groups. We start from empirical results reported in the literature on group rationality as collective group level competence and use data on real-life groups of four and five to validate a mathematical model. We then use this mathematical model to predict group level scores from a variety of possible group configurations (varying both in cognitive distance and average individual rationality). Our results show that both group competence and cognitive distance are necessary conditions for emergent group rationality. Group configurations, in which the groups become more rational than the most rational group member, are groups scoring low on cognitive distance and scoring high on absorptive capacity. PMID:25314132

  6. Spectroscopic study of low-temperature hydrogen absorption in palladium

    SciTech Connect

    Ienaga, K. Takata, H.; Onishi, Y.; Inagaki, Y.; Kawae, T.; Tsujii, H.; Kimura, T.

    2015-01-12

    We report real-time detection of hydrogen (H) absorption in metallic palladium (Pd) nano-contacts immersed in liquid H{sub 2} using inelastic electron spectroscopy (IES). After introduction of liquid H{sub 2}, the spectra exhibit the time evolution from the pure Pd to the Pd hydride, indicating that H atoms are absorbed in Pd nano-contacts even at the temperature where the thermal process is not expected. The IES time and bias voltage dependences show that H absorption develops by applying bias voltage 30 ∼ 50 mV, which can be explained by quantum tunneling. The results represent that IES is a powerful method to study the kinetics of high density H on solid surface.

  7. Spectroscopic study of low-temperature hydrogen absorption in palladium

    NASA Astrophysics Data System (ADS)

    Ienaga, K.; Takata, H.; Onishi, Y.; Inagaki, Y.; Tsujii, H.; Kimura, T.; Kawae, T.

    2015-01-01

    We report real-time detection of hydrogen (H) absorption in metallic palladium (Pd) nano-contacts immersed in liquid H2 using inelastic electron spectroscopy (IES). After introduction of liquid H2, the spectra exhibit the time evolution from the pure Pd to the Pd hydride, indicating that H atoms are absorbed in Pd nano-contacts even at the temperature where the thermal process is not expected. The IES time and bias voltage dependences show that H absorption develops by applying bias voltage 30 ˜ 50 mV, which can be explained by quantum tunneling. The results represent that IES is a powerful method to study the kinetics of high density H on solid surface.

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

    SciTech Connect

    Reynolds, Cormac; Punsly, Brian; O'Dea, Christopher P. E-mail: brian.punsly@comdev-usa.com

    2013-08-10

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

  9. HIGHLY IONIZED Fe-K ABSORPTION LINE FROM CYGNUS X-1 IN THE HIGH/SOFT STATE OBSERVED WITH SUZAKU

    SciTech Connect

    Yamada, S.; Yoshikawa, A.; Makishima, K.; Torii, S.; Noda, H.; Mineshige, S.; Ueda, Y.; Kubota, A.; Gandhi, P.; Done, C.

    2013-04-20

    We present observations of a transient He-like Fe K{alpha} absorption line in Suzaku observations of the black hole binary Cygnus X-1 on 2011 October 5 near superior conjunction during the high/soft state, which enable us to map the full evolution from the start to the end of the episodic accretion phenomena or dips for the first time. We model the X-ray spectra during the event and trace their evolution. The absorption line is rather weak in the first half of the observation, but instantly deepens for {approx}10 ks, and weakens thereafter. The overall change in equivalent width is a factor of {approx}3, peaking at an orbital phase of {approx}0.08. This is evidence that the companion stellar wind feeding the black hole is clumpy. By analyzing the line with a Voigt profile, it is found to be consistent with a slightly redshifted Fe XXV transition, or possibly a mixture of several species less ionized than Fe XXV. The data may be explained by a clump located at a distance of {approx}10{sup 10-12} cm with a density of {approx}10{sup (-13)-(-11)} g cm{sup -3}, which accretes onto and/or transits the line of sight to the black hole, causing an instant decrease in the observed degree of ionization and/or an increase in density of the accreting matter. Continued monitoring for individual events with future X-ray calorimeter missions such as ASTRO-H and AXSIO will allow us to map out the accretion environment in detail and how it changes between the various accretion states.

  10. THE DIAGNOSTIC O VI ABSORPTION LINE IN DIFFUSE PLASMAS: COMPARISON OF NON-EQUILIBRIUM IONIZATION STRUCTURE SIMULATIONS TO FUSE DATA

    SciTech Connect

    De Avillez, Miguel A.; Breitschwerdt, Dieter

    2012-12-20

    The nature of the interstellar O VI in the Galactic disk is studied by means of a multi-fluid hydrodynamical approximation, tracing the detailed time-dependent evolution of the ionization structure of the plasma. Our focus is to explore the signature of any non-equilibrium ionization condition present in the interstellar medium using the diagnostic O VI ion. A detailed comparison between the simulations and FUSE data is carried out by taking lines of sight (LOS) measurements through the simulated Galactic disk, covering an extent of 4 kpc from different vantage points. The simulation results bear a striking resemblance with the observations: (1) the N(O VI) distribution with distance and angle fall within the minimum and maximum values of the FUSE data; (2) the column density dispersion with distance is constant for all the LOS, showing a mild decrease at large distances; (3) O VI has a clumpy distribution along the LOS; and (4) the time-averaged midplane density for distances >400 pc has a value of (1.3-1.4) Multiplication-Sign 10{sup -8} cm{sup -3}. The highest concentration of O VI by mass occurs in the thermally stable (10{sup 3.9} K < T {<=} 10{sup 4.2} K; 20%) and unstable (10{sup 4.2} K < T < 10{sup 5} K; 50%) regimes, both well below its peak temperature in collisional ionization equilibrium, with the corresponding volume filling factors oscillating with time between 8%-20% and 4%-5%, respectively. These results may also be relevant for intergalactic metal absorption systems at high redshifts.

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

    SciTech Connect

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

    2013-08-01

    We present Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray weak, probably due to absorption by the shielding gas between the nucleus and the accretion-disk wind. The two targets are among the optically brightest BAL quasars, yet they are known to be significantly X-ray weak at rest-frame 2-10 keV (16-120 times fainter than typical quasars). We would expect to obtain Almost-Equal-To 400-600 hard X-ray ({approx}> 10 keV) photons with NuSTAR, provided that these photons are not significantly absorbed (N{sub H} {approx}< 10{sup 24} cm{sup -2}). However, both BAL quasars are only detected in the softer NuSTAR bands (e.g., 4-20 keV) but not in its harder bands (e.g., 20-30 keV), suggesting that either the shielding gas is highly Compton-thick or the two targets are intrinsically X-ray weak. We constrain the column densities for both to be N{sub H} Almost-Equal-To 7 Multiplication-Sign 10{sup 24} cm{sup -2} if the weak hard X-ray emission is caused by obscuration from the shielding gas. We discuss a few possibilities for how PG 1004+130 could have Compton-thick shielding gas without strong Fe K{alpha} line emission; dilution from jet-linked X-ray emission is one likely explanation. We also discuss the intrinsic X-ray weakness scenario based on a coronal-quenching model relevant to the shielding gas and disk wind of BAL quasars. Motivated by our NuSTAR results, we perform a Chandra stacking analysis with the Large Bright Quasar Survey BAL quasar sample and place statistical constraints upon the fraction of intrinsically X-ray weak BAL quasars; this fraction is likely 17%-40%.

  12. Weak Hard X-Ray Emission from Two Broad Absorption Line Quasars Observed with NuStar: Compton-Thick Absorption or Intrinsic X-Ray Weakness?

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

    We present Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray weak, probably due to absorption by the shielding gas between the nucleus and the accretion-disk wind. The two targets are among the optically brightest BAL quasars, yet they are known to be significantly X-ray weak at rest-frame 2-10 keV (16-120 times fainter than typical quasars). We would expect to obtain approx. or equal to 400-600 hard X-ray (is greater than or equal to 10 keV) photons with NuSTAR, provided that these photons are not significantly absorbed N(sub H) is less than or equal to 10(exp24) cm(exp-2). However, both BAL quasars are only detected in the softer NuSTAR bands (e.g., 4-20 keV) but not in its harder bands (e.g., 20-30 keV), suggesting that either the shielding gas is highly Compton-thick or the two targets are intrinsically X-ray weak. We constrain the column densities for both to be N(sub H) 7 × 10(exp 24) cm(exp-2) if the weak hard X-ray emission is caused by obscuration from the shielding gas. We discuss a few possibilities for how PG 1004+130 could have Compton-thick shielding gas without strong Fe Ka line emission; dilution from jet-linked X-ray emission is one likely explanation. We also discuss the intrinsic X-ray weakness scenario based on a coronal-quenching model relevant to the shielding gas and disk wind of BAL quasars. Motivated by our NuSTAR results, we perform a Chandra stacking analysis with the Large Bright Quasar Survey BAL quasar sample and place statistical constraints upon the fraction of intrinsically X-ray weak BAL quasars; this fraction is likely 17%-40%.

  13. An accelerated line-by-line option for MODTRAN combining on-the-fly generation of line center absorption within 0.1 cm-1 bins and pre-computed line tails

    NASA Astrophysics Data System (ADS)

    Berk, Alexander; Conforti, Patrick; Hawes, Fred

    2015-05-01

    A Line-By-Line (LBL) option is being developed for MODTRAN6. The motivation for this development is two-fold. Firstly, when MODTRAN is validated against an independent LBL model, it is difficult to isolate the source of discrepancies. One must verify consistency between pressure, temperature and density profiles, between column density calculations, between continuum and particulate data, between spectral convolution methods, and more. Introducing a LBL option directly within MODTRAN will insure common elements for all calculations other than those used to compute molecular transmittances. The second motivation for the LBL upgrade is that it will enable users to compute high spectral resolution transmittances and radiances for the full range of current MODTRAN applications. In particular, introducing the LBL feature into MODTRAN will enable first-principle calculations of scattered radiances, an option that is often not readily available with LBL models. MODTRAN will compute LBL transmittances within one 0.1 cm-1 spectral bin at a time, marching through the full requested band pass. The LBL algorithm will use the highly accurate, pressure- and temperature-dependent MODTRAN Padé approximant fits of the contribution from line tails to define the absorption from all molecular transitions centered more than 0.05 cm-1 from each 0.1 cm-1 spectral bin. The beauty of this approach is that the on-the-fly computations for each 0.1 cm-1 bin will only require explicit LBL summing of transitions centered within a 0.2 cm-1 spectral region. That is, the contribution from the more distant lines will be pre-computed via the Padé approximants. The status of the LBL effort will be presented. This will include initial thermal and solar radiance calculations, validation calculations, and self-validations of the MODTRAN band model against its own LBL calculations.

  14. Biopharmaceutics classification and intestinal absorption study of apigenin.

    PubMed

    Zhang, Jianjun; Liu, Dapeng; Huang, Yanting; Gao, Yuan; Qian, Shuai

    2012-10-15

    The aim of the study was to characterize the biopharmaceutics classification system (BCS) category of apigenin (AP) using intrinsic dissolution rate (IDR) and rat intestinal permeability, and to investigate the intestinal absorption mechanism of AP in rats. In the present investigation, equilibrium solubility and intrinsic dissolution rate (IDR) of AP were estimated in phosphate buffers. Effective intestinal permeability (P(eff)) of AP was determined using single-pass intestinal perfusion (SPIP) technique in four segments (duodenum, jejunum, ileum and colon) of rat intestine at three concentrations (10, 50 and 100 μg/ml). The aqueous solubility of AP in tested phosphate buffers was very poor with maximum solubility of 2.16 μg/ml at pH 7.5. The IDR of AP was very low with a value of 0.006 mg/min/cm(2). The minimum and maximum P(eff)s determined by SPIP were 0.198×10(-4) and 0.713×10(-4) cm/s at jejunum and duodenum site, respectively. In addition, the concentration-dependent permeability behavior was observed in the duodenum and jejunum, which suggested that AP was transported by both passive and active carrier-mediated saturable mechanism in these two intestinal segments. However, the observed concentration-independent permeability behavior in ileum and colon indicated primarily passive transport mechanism of absorption of AP in the last two intestinal segments. AP was classified as class II drug of the BCS due to its low solubility and high intestinal permeability. AP could be well absorbed in the whole intestine with the main absorption site at duodenum. The absorption of AP in four intestinal segments exhibited different transport mechanisms.

  15. Interstellar absorption along the line of sight to Sigma Scorpii using Copernicus observations

    NASA Technical Reports Server (NTRS)

    Allen, M. M.; Snow, T. P.; Jenkins, E. B.

    1990-01-01

    From Copernicus observations of Sigma Sco, 57 individual lines of 11 elements plus the molecular species H2 and CO were identified. By using a profile-fitting technique, rather than curves of growth, it was possible to obtain column densities and Doppler b values for up to four separate components along this line of sight. Electron density in the major H I component was derived from the photoionization equilibrium of sulfur, obtaining, n(e) of about 0.3/cu cm. The neutral hydrogen density in the same component was also derived using fine-structure excitation of O I. An H II component is also present in which the electron density was n(e) about 20/cu cm. As a by-product of this analysis, previously undetermined oscillator strengths for two Mn II lines were obtained: for 1162.-017 A, f about 0.023 and for 1164.211 A, f about 0.0086.

  16. A Two-Line Absorption Instrument for Scramjet Temperature and Water Vapor Concentration Measurement in HYPULSE

    NASA Technical Reports Server (NTRS)

    Tsai, C. Y.

    1998-01-01

    A three beam water vapor sensor system has been modified to provide for near simultaneous temperature measurement. The system employs a tunable diode laser to scan spectral line of water vapor. The application to measurements in a scramjet combustor environment of a shock tunnel facility is discussed. This report presents and discusses die initial calibration of the measurement system.

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

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

    We investigate the variability of C IV λ1549 broad absorption line (BAL) troughs over rest-frame timescales of up to ≈7 yr in 14 quasars at redshifts z >~ 2.1. For nine sources at sufficiently high redshift, we also compare the C IV and Si IV λ1400 absorption variation. We compare shorter and longer term variability using spectra from up to four different epochs per source and find complex patterns of variation in the sample overall. The scatter in the change of absorption equivalent width (EW), ΔEW, increases with the time between observations. BALs do not, in general, strengthen or weaken monotonically, and variation observed over shorter (lsimmonths) timescales is not predictive of multi-year variation. We find no evidence for asymmetry in the distribution of ΔEW that would indicate that BALs form and decay on different timescales, and we constrain the typical BAL lifetime to be gsim30 yr. The BAL absorption for one source, LBQS 0022+0150, has weakened and may now be classified as a mini-BAL. Another source, 1235+1453, shows evidence of variable, blue continuum emission that is relatively unabsorbed by the BAL outflow. C IV and Si IV BAL shape changes are related in at least some sources. Given their high velocities, BAL outflows apparently traverse large spatial regions and may interact with parsec-scale structures such as an obscuring torus. Assuming BAL outflows are launched from a rotating accretion disk, notable azimuthal symmetry is required in the outflow to explain the relatively small changes observed in velocity structure over times up to 7 yr.

  18. Absorption by ground-state lead atoms of the 283. 3-nm resonant line from a lead hollow cathode lamp. An absolute number density calibration

    SciTech Connect

    Simons, J.W. ); Oldenborg, R.C.; Baughcum, S.L. )

    1989-10-19

    An accurate absolute number density calibration curve for absorption by gaseous lead atoms of the 283.3-nm resonant line from a typical lead hollow cathode lamp is reported. This calibration shows the usual curvature in the Beer-Lambert plot for atomic absorption at moderate to high absorbances that is commonly attributed to self-absorption leading to line reversal in the source and/or preferential absorption at the line center when the absorber temperature is not much greater than the source Doppler temperature. A theoretical calculation utilizing a Doppler-limited Fourier transform spectrum of the 283.3-nm emission from the lamp and a tabulated value of the absorption cross section and accounting for the isotopic and nuclear hyperfine components in both the emission and absorption due to naturally occurring lead quantitatively reproduces the experimental calibration curve without any parameter adjustments. It is found that the curvature in the Beer-Lambert plot has more to do with the fact that the absorbing and emitting atoms are a mixture of isotopes giving several isotopic and nuclear hyperfine transitions at slightly different frequencies than it does with preferential absorption at line centers.

  19. Characterization of fine resolution field spectrometers using solar Fraunhofer lines and atmospheric absorption features.

    PubMed

    Meroni, Michele; Busetto, Lorenzo; Guanter, Luis; Cogliati, Sergio; Crosta, Giovanni Franco; Migliavacca, Mirco; Panigada, Cinzia; Rossini, Micol; Colombo, Roberto

    2010-05-20

    The accurate spectral characterization of high-resolution spectrometers is required for correctly computing, interpreting, and comparing radiance and reflectance spectra acquired at different times or by different instruments. In this paper, we describe an algorithm for the spectral characterization of field spectrometer data using sharp atmospheric or solar absorption features present in the measured data. The algorithm retrieves systematic shifts in channel position and actual full width at half-maximum (FWHM) of the instrument by comparing data acquired during standard field spectroscopy measurement operations with a reference irradiance spectrum modeled with the MODTRAN4 radiative transfer code. Measurements from four different field spectrometers with spectral resolutions ranging from 0.05 to 3.5nm are processed and the results validated against laboratory calibration. An accurate retrieval of channel position and FWHM has been achieved, with an average error smaller than the instrument spectral sampling interval.

  20. Possible evidence for a variable fine-structure constant from QSO absorption lines: systematic errors

    NASA Astrophysics Data System (ADS)

    Murphy, M. T.; Webb, J. K.; Flambaum, V. V.; Churchill, C. W.; Prochaska, J. X.

    2001-11-01

    Comparison of quasar (QSO) absorption spectra with laboratory spectra allows us to probe possible variations in the fundamental constants over cosmological time-scales. In a companion paper we present an analysis of Keck/HIRES spectra and report possible evidence suggesting that the fine-structure constant, α, may have been smaller in the past: [formmu2]Δα/α=(-0.72+/-0.18)×10-5 over the redshift range [formmu3]0.5

  1. Optical absorptance and thermomodulation studies of several A-15 compounds

    SciTech Connect

    McKee, R.C.

    1983-06-01

    The purpose of this work was to investigate the optical properties of several high T/sub c/ compounds in the form of sputtered films. The measurements are used toward this end: optical absorptance (using a calorimetric technique near 4.2K), which yields (after Kramers-Kronig analysis) the complex dielectric function, and thermoreflectance (which measures the change in reflectance in the optical range when a 1 to 10/sup 0/K temperature wave is applied), performed at two ambient temperatures (80 and 300/sup 0/K), yielding the differential dielectric function. The sputtered films included Nb/sub 3/Ge, Nb/sub 3/Al, V/sub 3/Ga and Nb/sub 3/Ir. It is noted that Nb/sub 3/Ir is not a high T/sub c/ superconductor. The thermoreflectance on the bulk samples V/sub 3/Si, V/sub 3/Ge and single crystal Cr/sub 3/Si were not performed because the samples were not in the form of thin films. The thermomodulation studies are correlated with the absorptance measurements in comparison to band structure calculations. When thermomodulation studies are performed on semiconductors, these studies yield information about critical points, but studies on metals indicate that Fermi-level transitions become important. It is thought that A-15 structured compounds, which have a high density of electron states around the Fermi level, will produce spectra due to this high density of states. Procedures and results are detailed.

  2. Infrared absorption study of neutron-transmutation-doped germanium

    NASA Technical Reports Server (NTRS)

    Park, I. S.; Haller, E. E.

    1988-01-01

    Using high-resolution far-infrared Fourier transform absorption spectroscopy and Hall effect measurements, the evolution of the shallow acceptor and donor impurity levels in germanium during and after the neutron transmutation doping process was studied. The results show unambiguously that the gallium acceptor level concentration equals the concentration of transmutated Ge-70 atoms during the whole process indicating that neither recoil during transmutation nor gallium-defect complex formation play significant roles. The arsenic donor levels appear at full concentration only after annealing for 1 h at 450 C. It is shown that this is due to donor-radiation-defect complex formation. Again, recoil does not play a significant role.

  3. The Hubble Space Telescope quasar absorption line key project. 6: Properties of the metal-rich systems

    NASA Technical Reports Server (NTRS)

    Bergeron, Jacqueline; Petitjean, Patrick; Sargent, W. L. W.; Bahcall, John N.; Boksenberg, Alec; Hartig, George F.; Jannuzi, Buell T.; Kirhakos, Sofia; Savage, Blair D.; Schneider, Donald P.

    1994-01-01

    We present an analysis of the properties of a sample of 18 metal-rich, low-redshift z(sub abs) much less than z(sub em) absorbers seen in low- and medium-resolution spectra obtained for the Quasar Absorption Line Key Project with the Hubble Space Telescope Faint Object Spectrograph (HST/FOS). For most of the C IV and Lyman-limit systems, observations in the optical wavelength range of the expected associated Mg II absorption are available. As at high redshift (z approximately 2), there are two subclasses of absorbers which are characterized by the presence or absence of MG II absorption. However, some low-redshift Mg II and Fe absorptions originate from regions optically thin to UV ionizing photons and thus, at low redshift, the low-ionization systems do not always trace high opacities, as is the case at high redshift. This implies that the mean ionization state of metal-rich, optically thin absorbing clouds falls with decreasing redshift, which is consistent with the hypothesis that the gas is photoionized by the metagalactic UV background radiation field. Two main constraints are derived from the analysis of the Lyman-limit sample, assuming photoionization models are valid. First, a low opacity to ionizing photons (tau(sub LL) approximately less than 1), as observed for several Mg II-Fe II systems at z approximately 0.5, sets limits on the ionization level of hydrogen, thus on the total hydrogen column density and the heavy element abundances, (Z/H) approximately -0.5 to -0.3. Second, the dimensions of individual Mg II clouds are smaller than at high redshift by a factor 3-10. At z approximately greater than 0.6, the O VI absorption doublet is detected in four of the five z(sub abs) much less than z(sub em) systems for which the O VI wavelength range has been observed, whereas the associated N V doublet is detected in only two cases. This suggests that the presence of a high-ionization O VI phase is a general property of z approximately 0.6-1 absorption systems

  4. A doubly curved elliptical crystal spectrometer for the study of localized x-ray absorption in hot plasmas

    SciTech Connect

    Cahill, Adam D. Hoyt, Cad L.; Pikuz, Sergei A.; Shelkovenko, Tania; Hammer, David A.

    2014-10-15

    X-ray absorption spectroscopy is a powerful tool for the diagnosis of plasmas over a wide range of both temperature and density. However, such a measurement is often limited to probing plasmas with temperatures well below that of the x-ray source in order to avoid object plasma emission lines from obscuring important features of the absorption spectrum. This has excluded many plasmas from being investigated by this technique. We have developed an x-ray spectrometer that provides the ability to record absorption spectra from higher temperature plasmas than the usual approach allows without the risk of data contamination by line radiation emitted by the plasma under study. This is accomplished using a doubly curved mica crystal which is bent both elliptically and cylindrically. We present here the foundational work in the design and development of this spectrometer along with initial results obtained with an aluminum x-pinch as the object plasma.

  5. The HST quasar absorption line key project. 4: HST faint-object spectrograph and ground-based observations of the unusual low-redshift broad absorption-line quasi-stellar object PG 0043+039

    NASA Technical Reports Server (NTRS)

    Turnshek, David A.; Espey, Brian R.; Kopko, Michael, Jr.; Rauch, Michael; Weymann, Ray J.; Jannuzi, Buell T.; Boksenberg, Alec; Bergeron, Jacqueline; Hartig, George F.; Sargent, W. L. W.

    1994-01-01

    Hubble Space Telescope Faint Object Spectrograph (HST FOS) observations have shown that the spectrum of the low-redshift (z(sub em) approximately equal to 0.384) QSO PG 0043+039 exhibits weak broad absorption lines (BALs). The BALs were discovered during the course of UV spectrophotometry made for the HST Quasar Absorption Line Key Project. The HST data are analyzed along with ground-based optical and IUE spectrophotometry. The object is found to have a number of atypical properties relative to normal non-BAL QSOs. The observed continuum is atypical in the sense that it is much weaker than that of a normal optically selected QSO at rest wavelengths approximately less than 2200 A. Intrinsic reddening of E(B-V) approximately equal to 0.11 mag by dust similar to that found in the SMC at the redshift of PG 0043+039 conservatively accounts for the observed continuum shape moderately well. These observed characteristics are typical of low-ionization BAL QSOs, but convincing evidence for BALs due to low-ionization transitions of Mg II, Al III, Al II, or C II does not exist. Therefore, this object may be a misaligned BAL QSO having many of the characteristics of low-ionization BAL QSOs with the sight line passing through a putative dusty region, but evidently missing clouds of high enough column density to produce observable low-ionization BALs. If the intrinsic dust-extinction model is correct, the observations suggest that the dust is not confined to the presumably higher density, low-ionization BAL clouds, but that it has drifted to nearby high-ionization BAL regions. We also consider other possible mechanisms for producing the shape of the continuous energy distribution which cannot be ruled out. We compare the Fe II emission in PG 0043+039 with that in another Key Project QSO, NGC 2841-UB 3, which has optical Fe II emission comparable in strength to that in PG 0043+039, but has anomalously weak UV Fe II emission. In addition, from an analysis of UV and optical

  6. X-ray absorption studies of battery materials

    SciTech Connect

    McBreen, J.

    1996-10-01

    X-ray absorption spectroscopy (XAS) is ideal for {ital in}{ital situ} studies of battery materials because both the probe and signal are penetrating x rays. The advantage of XAS being element specific permits investigation of the environment of a constituent element in a composite material. This makes it very powerful for studying electrode additives and corrosion of individual components of complex metal hydride alloys. The near edge part of the spectrum (XANES) provides information on oxidation state and site symmetry of the excited atom. This is particularly useful in study of corrosion and oxidation changes in cathode materials during charge/discharge cycle. Extended fine structure (EXAFS) gives structural information. Thus the technique provides both chemical and structural information. Since XAS probes only short range order, it can be applied to study of amorphous electrode materials and electrolytes. This paper discusses advantages and limitations of the method, as well as some experimental aspects.

  7. Atmospheric Profiling Combining the Features of GPS ro & Mls: Satellite to Satellite Occultations Near Water & Ozone Absorption Lines

    NASA Astrophysics Data System (ADS)

    Kursinski, E. R.; Ward, D.; Otarola, A. C.; McGhee, J.; Reed, H.; Erickson, D.

    2015-12-01

    Assessing climate models & their predictions requires observations that determine the state of the real climate system precisely and unambiguously, independently from models. For this purpose, we have been developing a new orbiting remote sensing system called the Active Temperature, Ozone & Moisture Microwave Spectrometer (ATOMMS) which is a cross between GPS RO and the Microwave Limb Sounder. ATOMMS actively probes water vapor, ozone & other absorption lines at cm & mm wavelengths in a satellite to satellite occultation geometry to simultaneously profile temperature, pressure, water vapor and ozone as well as other important constituents. Individual profiles of water vapor, temperature & pressure heights will extend from near the surface into the mesosphere with ~1%, 0.4K and 10 m precision respectively and still better accuracy, with 100 m vertical resolution. Ozone profiles will extend upward from the upper troposphere. Line of sight wind profiles will extend upwards from the mid-stratosphere. ATOMMS is a doubly differential absorption system which eliminates drift and both sees clouds and sees thru them, to deliver performance in clouds within a factor of 2 of the performance in clear skies. This all-weather sampling combined with insensitivity to surface emissivity avoids sampling biases that limit most existing satellite records. ATOMMS will profile slant liquid water in clouds & rain and as well as turbulence via scintillations ("twinkling of a star"). Using prototype ATOMMS instrumentation that we developed with funding from NSF, several ATOMMS ground field campaigns precisely measured water vapor, cloud amount, rainfall, turbulence and absorption line spectroscopy. ATOMMS's dynamic range was demonstrated as water vapor was derived to 1% precision in optical depths up to 17. We are developing high altitude aircraft to aircraft instrumentation to further demonstrate ATOMMS performance, refine spectroscopy & support future field campaigns. Our vision is a

  8. Intersstellar absorption lines between 2000 and 3000 A in nearby stars observed with BUSS. [Balloon Borne Ultraviolet Spectrophotometer

    NASA Technical Reports Server (NTRS)

    De Boer, K. S.; Lenhart, H.; Van Der Hucht, K. A.; Kamperman, T. M.; Kondo, Y.

    1986-01-01

    Spectra obtained between 2000 and 3000 A with the Balloon Borne Ultraviolet Spectrophotometer (BUSS) payload were examined for interstellar absorption lines. In bright stars, with spectral types between O9V and F5V, such lines were measured of Mg I, Mg II, Cr II, Mn II, Fe II and Zn II, with Cr II and Zn II data of especially high quality. Column densities were derived and interstellar abundances were determined for the above species. It was found that metal depletion increases with increasing E(B-V); Fe was most affected and Zn showed a small depletion for E(B-V) greater than 0.3 towards Sco-Oph. The metal column densities, derived for Alpha-And, Kappa-Dra, Alpha-Com, Alpha-Aql, and 29 Cyg were used to infer N(H I). It was shown that the ratio of Mg I to Na I is instrumental in determining the ionization structure along each line of sight. The spectra of Aql stars confirms the presence of large gas densities near Alpha-Oph. Moreover, data indicated that the Rho-Oph N(H I) value needs to be altered to 35 x 10 to the 20th/sq cm, based on observed ion ratios and analysis of the Copernicus L-alpha profile.

  9. Galactic Soft X-ray Emission Revealed with Spectroscopic Study of Absorption and Emission Spectra

    NASA Astrophysics Data System (ADS)

    Yamasaki, Noriko Y.; Mitsuda, K.; Takei, Y.; Hagihara, T.; Yoshino, T.; Wang, Q. D.; Yao, Y.; McCammon, D.

    2010-03-01

    Spectroscopic study of Oxygen emission/absorption lines is a new tool to investigate the nature of the soft X-ray background. We investigated the emission spectra of 14 fields obtained by Suzaku, and detected OVII and OVIII lines separately. There is an almost isotropic OVII line emission with 2 LU intensity. As the attenuation length in the Galactic plane for that energy is short, that OVII emission should arise within 300 pc of our neighborhood. In comparison with the estimated emission measure for the local bubble, the most plausible origin of this component is the solar wind charge exchange with local interstellar materials. Another component presented from the correlation between the OVII and OVIII line intensity is a thermal emission with an apparent temperature of 0.2 keV with a field-to-field fluctuation of 10% in temperature, while the intensity varies about a factor of 4. By the combination analysis of the emission and the absorption spectra, we can investigate the density and the scale length of intervening plasma separately. We analyzed the Chanrdra grating spectra of LMC X-3 and PKS 2155-304, and emission spectra toward the line of sight by Suzaku. In both cases, the combined analysis showed that the hot plasma is not iso-thermal nor uniform. Assuming an exponential disk distribution, the thickness of the disk is as large as a few kpc. It suggests that there is a thick hot disk or hot halo surrounding our Galaxy, which is similar to X-ray hot haloes around several spiral galaxies.

  10. In-Line Capacitance Sensor for Real-Time Water Absorption Measurements

    NASA Technical Reports Server (NTRS)

    Nurge, Mark A.; Perusich, Stephen A.

    2010-01-01

    A capacitance/dielectric sensor was designed, constructed, and used to measure in real time the in-situ water concentration in a desiccant water bed. Measurements were carried out with two experimental setups: (1) passing nitrogen through a humidity generator and allowing the gas stream to become saturated at a measured temperature and pressure, and (2) injecting water via a syringe pump into a nitrogen stream. Both water vapor generating devices were attached to a downstream vertically-mounted water capture bed filled with 19.5 g of Moisture Gone desiccant. The sensor consisted of two electrodes: (1) a 1/8" dia stainless steel rod placed in the middle of the bed and (2) the outer shell of the stainless steel bed concentric with the rod. All phases of the water capture process (background, heating, absorption, desorption, and cooling) were monitored with capacitance. The measured capacitance was found to vary linearly with the water content in the bed at frequencies above 100 kHz indicating dipolar motion dominated the signal; below this frequency, ionic motion caused nonlinearities in the water concentration/capacitance relationship. The desiccant exhibited a dielectric relaxation whose activation energy was lowered upon addition of water indicating either a less hindered rotational motion or crystal reorientation.

  11. X-Ray Weak Broad-Line Quasars: Absorption or Intrinsic X-Ray Weakness

    NASA Technical Reports Server (NTRS)

    Risaliti, Guido; Mushotzky, Richard F. (Technical Monitor)

    2004-01-01

    XMM observations of X-ray weak quasars have been performed during 2003. The data for all but the last observation are now available (there has been a delay of several months on the initial schedule, due to high background flares which contaminated the observations: as a consequence, most of them had to be rescheduled). We have reduced and analyzed these data, and obtained interesting preliminary scientific results. Out of the eight sources, 4 are confirmed to be extrimely X-ray weak, in agreement with the results of previous Chandra observations. 3 sources are confirmed to be highly variable both in flux (by factors 20-50) and in spectral properties (dramatic changes in spectral index). For both these groups of objects, an article is in preparation. Preliminary results have been presented at an international workshop on AGN surveys in December 2003, in Cozumel (Mexico). In order to further understand the nature of these X-ray weak quasars, we submitted proposals for spectroscopy at optical and infrared telescopes. We obtained time at the TNG 4 meter telescope for near-IR observations, and at the Hobby-Eberly Telescope for optical high-resolution spectroscopy. These observations will be performed in early 2004, and will complement the XMM data, in order to understand whether the X-ray weakness of these sources is an intrinsic property or is due to absorption by circumnuclear material.

  12. Limits on variations in fundamental constants from 21-cm and ultraviolet Quasar absorption lines.

    PubMed

    Tzanavaris, P; Webb, J K; Murphy, M T; Flambaum, V V; Curran, S J

    2005-07-22

    Quasar absorption spectra at 21-cm and UV rest wavelengths are used to estimate the time variation of x [triple-bond] alpha(2)g(p)mu, where alpha is the fine structure constant, g(p) the proton g factor, and m(e)/m(p) [triple-bond] mu the electron/proton mass ratio. Over a redshift range 0.24 < or = zeta(abs) < or = 2.04, (Deltax/x)(weighted)(total) = (1.17 +/- 1.01) x 10(-5). A linear fit gives x/x = (-1.43 +/- 1.27) x 10(-15) yr(-1). Two previous results on varying alpha yield the strong limits Deltamu/mu = (2.31 +/- 1.03) x 10(-5) and Deltamu/mu=(1.29 +/- 1.01) x10(-5). Our sample, 8 x larger than any previous, provides the first direct estimate of the intrinsic 21-cm and UV velocity differences 6 km s(-1).

  13. Excitation ahead of shock fronts in krypton measured by single line laser absorption

    NASA Astrophysics Data System (ADS)

    Boetticher, W.; Kilpin, D.

    1984-12-01

    The absorption of single-mode radiation (from a dye laser tuned to 587.25 and 557.18 nm) by Kr in front of shock waves with Mach numbers 12-21 in a 50-mm-diameter 4.4-m-long free-position driver shock tube at preshock pressures 0.7-2.7 kPa is measured to determine the number densities of the metastable 5s(1 1/2)2 and 5s(1 1/2)1 precursor states (1s5 and 1s4 in Paschen notation, respectively). The measurement technique and calculations follow those of Ernst (1982). The results are presented in tables and graphs and characterized in comparison with previous findings. The time constant of the exponential rise of the precursor is found to be about 8 microsec, and the concentration of 1s5 + 1s4 for Mach 20 is calculated as about 10 ppm, in agreement (to within a factor of 5) with model predictions for Ar and Xe.

  14. Interstellar absorption along the line of sight to Theta Carinae using Copernicus observations

    NASA Technical Reports Server (NTRS)

    Allen, M. M.; Jenkins, E. B.; Snow, T. P.

    1992-01-01

    A profile fitting technique is employed to identify the velocities and Doppler b values for H I and H II clouds along the line of sight to Theta Car. Total abundances and depletions for 12 elements, plus column densities for the J = 0 to J = 5 rotational levels of H2 are obtained. Electron densities for both clouds are calculated from the ratios of the fine-structure levels of C II and N II, obtaining 0.08/cu cm and 1.2/cu cm. The fine-structure levels of C I, which led to 120/cu cm, are used to calculate the neutral hydrogen density for the H I region. D I is also present in the data from the Theta Car line of sight, yielding a D/H ratio of 5 x 10 exp -6. Elemental depletions are calculated for the H I region as well. Comparison of the results for Theta Car and those for Zeta Oph and Alpha Vir shows that the absolute depletions are different; however, the relative depletions are remarkably stable for different physical conditions.

  15. Ca II AND Na I QUASAR ABSORPTION-LINE SYSTEMS IN AN EMISSION-SELECTED SAMPLE OF SDSS DR7 GALAXY/QUASAR PROJECTIONS. I. SAMPLE SELECTION

    SciTech Connect

    Cherinka, B.; Schulte-Ladbeck, R. E.

    2011-10-15

    The aim of this project is to identify low-redshift host galaxies of quasar absorption-line systems by selecting galaxies that are seen in projection onto quasar sightlines. To this end, we use the Seventh Data Release of the Sloan Digital Sky Survey to construct a parent sample of 97,489 galaxy/quasar projections at impact parameters of up to 100 kpc to the foreground galaxy. We then search the quasar spectra for absorption-line systems of Ca II and Na I within {+-}500 km s{sup -1} of the galaxy's velocity. This yields 92 Ca II and 16 Na I absorption systems. We find that most of the Ca II and Na I systems are sightlines through the Galactic disk, through high-velocity cloud complexes in our halo, or Virgo Cluster sightlines. Placing constraints on the absorption line rest equivalent width significance ({>=}3.0{sigma}), the local standard of rest velocity along the sightline ({>=}345 km s{sup -1}), and the ratio of the impact parameter to the galaxy optical radius ({<=}5.0), we identify four absorption-line systems that are associated with low-redshift galaxies at high confidence, consisting of two Ca II systems (one of which also shows Na I) and two Na I systems. These four systems arise in blue, {approx}L*{sub r} galaxies. Tables of the 108 absorption systems are provided to facilitate future follow-up.

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

    SciTech Connect

    Hayashi, Takayuki J.; Nagai, Hiroshi; Doi, Akihiro

    2013-07-20

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

  17. A FOURTH H I 21 cm ABSORPTION SYSTEM IN THE SIGHT LINE OF MG J0414+0534: A RECORD FOR INTERVENING ABSORBERS

    SciTech Connect

    Tanna, A.; Webb, J. K.; Curran, S. J.; Whiting, M. T.; Bignell, C.

    2013-08-01

    We report the detection of a strong H I 21 cm absorption system at z = 0.5344, as well as a candidate system at z = 0.3389, in the sight line toward the z = 2.64 quasar MG J0414+0534. This, in addition to the absorption at the host redshift and the other two intervening absorbers, takes the total to four (possibly five). The previous maximum number of 21 cm absorbers detected along a single sight line is two and so we suspect that this number of gas-rich absorbers is in some way related to the very red color of the background source. Despite this, no molecular gas (through OH absorption) has yet been detected at any of the 21 cm redshifts, although, from the population of 21 cm absorbers as a whole, there is evidence for a weak correlation between the atomic line strength and the optical-near-infrared color. In either case, the fact that so many gas-rich galaxies (likely to be damped Ly{alpha} absorption systems) have been found along a single sight line toward a highly obscured source may have far-reaching implications for the population of faint galaxies not detected in optical surveys, a possibility which could be addressed through future wide-field absorption line surveys with the Square Kilometer Array.

  18. Frequency doubling of 1560nm diode laser via PPLN and PPKTP crystals and frequency stabilization to rubidium absorption line

    NASA Astrophysics Data System (ADS)

    Guo, Shanlong; Yang, Jianfeng; Yang, Baodong; Zhang, Tiancai; Wang, Junmin

    2010-11-01

    In our experiment, a polarization-maintaining (PM) fiber-pigtailed butterfly-sealed 1560nm distributed-feedback (DFB) laser diode is amplified by a 5-Watt EDFA, then a multiple-period PPLN crystal (1mm×10mm×20mm) and a single-period PPKTP crystal (1mm×2mm×30mm) are utilized to perform SHG via single pass configuration. The second harmonic power of ~ 239 mW@780 nm for PPLN and ~ 210 mW@780 nm for PPKTP are obtained with ~5W@1560 nm laser input, corresponding to SHG efficiency of ~ 5.2% for PPLN and ~ 4.4% for PPKTP, respectively. Finally the 1560 nm laser diode's frequency is locked to rubidium absorption line via SHG and rubidium absorption spectroscopy, the laser frequency drift for free-running case is ~ 56 MHz in 30 s, the residual frequency after being locked drift is ~ +/- 3.5 MHz.

  19. Atmospheric profiling via satellite to satellite occultations near water and ozone absorption lines for weather and climate

    NASA Astrophysics Data System (ADS)

    Kursinski, E. R.; Ward, D.; Otarola, A. C.; McGhee, J.; Stovern, M.; Sammler, K.; Reed, H.; Erickson, D.; McCormick, C.; Griggs, E.

    2016-05-01

    Significantly reducing weather and climate prediction uncertainty requires global observations with substantially higher information content than present observations provide. While GPS occultations have provided a major advance, GPS observations of the atmosphere are limited by wavelengths chosen specifically to minimize interaction with the atmosphere. Significantly more information can be obtained via satellite to satellite occultations made at wavelengths chosen specifically to characterize the atmosphere. Here we describe such a system that will probe cm- and mmwavelength water vapor absorption lines called the Active Temperature, Ozone and Moisture Microwave Spectrometer (ATOMMS). Profiling both the speed and absorption of light enables ATOMMS to profile temperature, pressure and humidity simultaneously, which GPS occultations cannot do, as well as profile clouds and turbulence. We summarize the ATOMMS concept and its theoretical performance. We describe field measurements made with a prototype ATOMMS instrument and several important capabilities demonstrated with those ground based measurements including retrieving temporal variations in path-averaged water vapor to 1%, in clear, cloudy and rainy conditions, up to optical depths of 17, remotely sensing turbulence and determining rain rates. We conclude with a vision of a future ATOMMS low Earth orbiting satellite constellation designed to take advantage of synergies between observational needs for weather and climate, ATOMMS unprecedented orbital remote sensing capabilities and recent cubesat technological innovations that enable a constellation of dozens of very small spacecraft to achieve many critical, but as yet unfulfilled, monitoring and forecasting needs.

  20. X-ray absorption studies of gamma irradiated Nd doped phosphate glass

    SciTech Connect

    Rai, V. N.; Rajput, Parasmani; Jha, S. N.; Bhattacharyya, D.

    2015-06-24

    This paper presents the X-ray absorption near edge structure (XANES) studies of Nd doped phosphate glasses before and after gamma irradiation. The intensity and location of L{sub III} edge white line peak of Nd changes depending on its concentration as well as on the ratio of O/Nd in the glass matrix. The decrease in the peak intensity of white line after gamma irradiation indicates towards reduction of Nd{sup 3+} to Nd{sup 2+} in the glass matrix, which increases with an increase in the doses of gamma irradiation. Similarity in the XANES spectra of Nd doped phosphate glasses and Nd{sub 2}O{sub 3} suggests that coordination geometry around Nd{sup 3+} in glass samples may be identical to that of Nd{sub 2}O{sub 3}.

  1. Side-line tunable laser transmitter for differential absorption lidar measurements of CO2: design and application to atmospheric measurements

    NASA Astrophysics Data System (ADS)

    Koch, Grady J.; Beyon, Jeffrey Y.; Gibert, Fabien; Barnes, Bruce W.; Ismail, Syed; Petros, Mulugeta; Petzar, Paul J.; Yu, Jirong; Modlin, Edward A.; Davis, Kenneth J.; Singh, Upendra N.

    2008-03-01

    A 2 μm wavelength, 90 mJ, 5 Hz pulsed Ho laser is described with wavelength control to precisely tune and lock the wavelength at a desired offset up to 2.9 GHz from the center of a CO2 absorption line. Once detuned from the line center the laser wavelength is actively locked to keep the wavelength within 1.9 MHz standard deviation about the setpoint. This wavelength control allows optimization of the optical depth for a differential absorption lidar (DIAL) measuring atmospheric CO2 concentrations. The laser transmitter has been coupled with a coherent heterodyne receiver for measurements of CO2 concentration using aerosol backscatter; wind and aerosols are also measured with the same lidar and provide useful additional information on atmospheric structure. Range-resolved CO2 measurements were made with <2.4% standard deviation using 500 m range bins and 6.7 min⁡ (1000 pulse pairs) integration time. Measurement of a horizontal column showed a precision of the CO2 concentration to <0.7% standard deviation using a 30 min⁡ (4500 pulse pairs) integration time, and comparison with a collocated in situ sensor showed the DIAL to measure the same trend of a diurnal variation and to detect shorter time scale CO2 perturbations. For vertical column measurements the lidar was setup at the WLEF tall tower site in Wisconsin to provide meteorological profiles and to compare the DIAL measurements with the in situ sensors distributed on the tower up to 396 m height. Assuming the DIAL column measurement extending from 153 m altitude to 1353 m altitude should agree with the tower in situ sensor at 396 m altitude, there was a 7.9 ppm rms difference between the DIAL and the in situ sensor using a 30 min⁡ rolling average on the DIAL measurement.

  2. Comparative study of water sorption and solubility of soft lining materials in the different solutions.

    PubMed

    Dinçkal Yanikoglu, Nuran; Yeşil Duymuş, Zeynep

    2004-06-01

    In this study, two acrylic based materials and three silicone rubber soft lining materials were investigated to determine the percentage of absorption and solubility in artificial saliva, distilled water, and denture cleanser. In addition, the effect of denture cleanser on surface properties of soft lining materials was also evaluated. For sorption and solubility testing, 75 discs (50 mm x 0.5 mm) were prepared and divided into 5 groups with 15 samples in each group. The specimens were stored in different solutions, and tested after 1, 4, and 16 weeks. Analysis of variance was used to find the significant differences between the materials at all time intervals. The acrylic resin soft lining materials had higher solubility (3.432% Visco-gel in artificial saliva) and absorption (3.349% Visco-gel in distilled water) than Molloplast-B after 16 weeks of aging. The greatest hardness and color change were shown in the acrylic soft lining materials.

  3. Broadening of the infrared absorption lines at reduced temperatures. II - Carbon monoxide in an atmosphere of carbon dioxide.

    NASA Technical Reports Server (NTRS)

    Tubbs, L. D.; Williams, D.

    1972-01-01

    The strengths of the rotational lines in the R branch of the CO fundamental have been determined at temperatures of 298, 202, and 132 K by means of a high-resolution spectrograph. The results can be used to determine line strengths at other temperatures by means of the Herman-Wallis relation or by considerations of the populations of the rotational levels in the ground vibrational state. Parameters describing the self-broadening and carbon dioxide broadening of CO lines have been determined at 298 and 202 K. The results are compared with other recent experimental and theoretical studies.

  4. An STIS Atlas of Ca II Triplet Absorption Line Kinematics in Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Batcheldor, D.; Axon, D.; Valluri, M.; Mandalou, J.; Merritt, D.

    2013-09-01

    The relations observed between supermassive black holes and their host galaxies suggest a fundamental link in the processes that cause these two objects to evolve. A more comprehensive understanding of these relations could be gained by increasing the number of supermassive black hole mass (M •) measurements. This can be achieved, in part, by continuing to model the stellar dynamics at the centers of galactic bulges using data of the highest possible spatial resolution. Consequently, we present here an atlas of galaxies in the Space Telescope Imaging Spectrograph (STIS) data archive that may have spectra suitable for new M • estimates. Archived STIS G750M data for all non-barred galactic bulges are co-aligned and combined, where appropriate, and the radial signal-to-noise ratios calculated. The line-of-sight velocity distributions from the Ca II triplet are then determined using a maximum penalized likelihood method. We find 19 out of 42 galaxies may provide useful new M • estimates since they are found to have data that is comparable in quality with data that has been used in the past to estimate M •. However, we find no relation between the signal-to-noise ratio in the previously analyzed spectra and the uncertainties of the black hole masses derived from the spectra. We also find that there is a very limited number of appropriately observed stellar templates in the archive from which to estimate the effects of template mismatching. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

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

    SciTech Connect

    Kunert-Bajraszewska, Magdalena; Katarzynski, Krzysztof; Siemiginowska, Aneta; Janiuk, Agnieszka

    2009-11-10

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

  6. Unveiling the X-ray/UV properties of AGN winds using Broad and mini-Broad Absorption Line Quasars

    NASA Astrophysics Data System (ADS)

    Giustini, M.

    2015-07-01

    BAL/mini-BALs are observed in the UV spectra of ˜ 20-30% of optically selected AGN as broad absorption troughs blueshifted by several thousands km/s, indicative of powerful nuclear winds. They could be representative of the average AGN if their winds cover only 20-30% of the continuum source, and/or represent an evolutionary state analogous to the high-soft state of BHB, when the jet emission is quenched and strong X-ray absorbing equatorial disk winds are virtually ubiquitous. High-quality, possibly time-resolved X-ray/UV studies are crucial to assess the global amount and 'character' of absorption in BAL/mini-BAL QSOs and to constrain the physical mechanism responsible for the launch and acceleration of their winds, therefore placing them in the broader context of AGN geometry and evolution. I will review here the known X-ray properties of BAL/mini-BAL QSOs, and present new results from a comprehensive X-ray spectral analysis of all the Palomar-Green BAL/mini-BAL QSOs with available XMM-Newton observations, for a total of 51 pointings of 14 different sources. These will include the most recent results from a high-quality simultaneous XMM/HST observational campaign on the mini-BAL QSO PG 1126-041, that unveiled with stunning details the X-ray/UV connection in action in an AGN disk wind through correlated X-ray/UV absorption variability.

  7. Optical depth ratios and metal-line absorption around z≈2.3 star-forming galaxies: insights from observations and simulations

    NASA Astrophysics Data System (ADS)

    Turner, Monica; Schaye, Joop; Steidel, Charles C.; Rudie, Gwen C.; Strom, Allison

    2015-01-01

    We study metal-line absorption around 854 z≈2.3 star-forming galaxies taken from the Keck Baryonic Structure Survey. The galaxies in this survey lie in the fields of 15 hyper-luminous background QSOs, with galaxy impact parameters ranging from 35 proper kpc (pkpc) to 2 proper Mpc (pMpc). Using the pixel optical depth technique, we present the first galaxy-centered 2-D maps of the median absorption by OVI, NV, CIV, CIII, and SiIV, as well as updated results for HI. At small galactocentric radii we detect a strong enhancement of the absorption relative to randomly located regions that extend out to at least 180 pkpc in the transverse direction, and ±240 km s-1 along the line-of-sight (LOS, ˜1 pMpc in the case of pure Hubble flow) for all ions except NV. Limiting the sample to the 340 galaxies with redshifts measured from nebular emission lines does not decrease the extent of the enhancement along the LOS compared to that in the transverse direction, which rules out redshift errors as the source of the observed redshift-space anisotropy and implies that we have detected the signature of gas peculiar velocities from infall, outflows, or virial motions. Looking next at optical depth ratios, we isolate pixel pairs at small galactocentric distances (within 180 pkpc in the transverse direction and 170 km s-1 along the LOS) and find that the optical depth of OVI at fixed HI is enhanced with respect to the full sample. Comparison with CLOUDY models, and assuming photoionisation, results in nearly solar metallicities at intergalactic overdensities, which we consider to be unphysical. Invoking collisional ionisation, we are able to place a lower limit on [O/H] of ˜1/100th solar, and conclude that we are likely probing collisionally ionised gas near galaxies. Finally, we turn to the EAGLE cosmological hydrodynamical simulations to interpret our results, and furthermore to study the evolution of the column density profiles as a function of impact parameter for different

  8. The 13CH4 absorption spectrum in the Icosad range (6600-7692 cm-1) at 80 K and 296 K: Empirical line lists and temperature dependence

    NASA Astrophysics Data System (ADS)

    Campargue, A.; Béguier, S.; Zbiri, Y.; Mondelain, D.; Kassi, S.; Karlovets, E. V.; Nikitin, A. V.; Rey, M.; Starikova, E. N.; Tyuterev, Vl. G.

    2016-08-01

    The 13CH4 absorption spectrum has been recorded at 296 K and 80 K in the Icosad range between 6600 and 7700 cm-1. The achieved noise equivalent absorption of the spectra recorded by differential absorption spectroscopy (DAS) is about αmin ≈ 1.5 × 10-7 cm-1. Two empirical line lists were constructed including 17,792 and 24,139 lines at 80 K and 296 K, respectively. For comparison, the HITRAN database provides only 1040 13CH4 lines in the region determined from methane spectra with natural isotopic abundance. Empirical values of the lower state energy level, Eemp, were systematically derived from the intensity ratios of the lines measured at 80 K and 296 K. Overall 10,792 Eemp values were determined providing accurate temperature dependence for most of the 13CH4 absorption in the region (93% and 82% at 80 K and 296 K, respectively). The quality of the derived empirical values of the lower state rotational quantum number, Jemp, is illustrated by their clear propensity to be close to an integer. A good agreement is achieved between our small Jemp values, with previous accurate determinations obtained by applying the 2T method to jet and 80 K spectra. The line lists at 296 K and 80 K which are provided as Supplementary material will be used for future rovibrational assignments based on accurate variational calculations.

  9. Evidence for ultra-fast outflows in radio-quiet AGNs. I. Detection and statistical incidence of Fe K-shell absorption lines

    NASA Astrophysics Data System (ADS)

    Tombesi, F.; Cappi, M.; Reeves, J. N.; Palumbo, G. G. C.; Yaqoob, T.; Braito, V.; Dadina, M.

    2010-10-01

    Context. Blue-shifted Fe K absorption lines have been detected in recent years between 7 and 10 keV in the X-ray spectra of several radio-quiet AGNs. The derived blue-shifted velocities of the lines can often reach mildly relativistic values, up to 0.2-0.4c. These findings are important because they suggest the presence of a previously unknown massive and highly ionized absorbing material outflowing from their nuclei, possibly connected with accretion disk winds/outflows. Aims: The scope of the present work is to statistically quantify the parameters and incidence of the blue-shifted Fe K absorption lines through a uniform analysis on a large sample of radio-quiet AGNs. This allows us to assess their global detection significance and to overcome any possible publication bias. Methods: We performed a blind search for narrow absorption features at energies greater than 6.4 keV in a sample of 42 radio-quiet AGNs observed with XMM-Newton. A simple uniform model composed by an absorbed power-law plus Gaussian emission and absorption lines provided a good fit for all the data sets. We derived the absorption lines parameters and calculated their detailed detection significance making use of the classical F-test and extensive Monte Carlo simulations. Results: We detect 36 narrow absorption lines on a total of 101 XMM-Newton EPIC pn observations. The number of absorption lines at rest-frame energies higher than 7 keV is 22. Their global probability to be generated by random fluctuations is very low, less than 3 × 10-8, and their detection have been independently confirmed by a spectral analysis of the MOS data, with associated random probability <10-7. We identify the lines as Fe XXV and Fe XXVI K-shell resonant absorption. They are systematically blue-shifted, with a velocity distribution ranging from zero up to ~0.3c, with a peak and mean value at ~0.1c. We detect variability of the lines on both EWs and blue-shifted velocities among different XMM-Newton observations

  10. Measurements of mesospheric water vapour, aerosols and temperatures with the Spectral Absorption Line Imager (SALI-AT)

    NASA Astrophysics Data System (ADS)

    Shepherd, M. G.; Mullins, M.; Brown, S.; Sargoytchev, S. I.

    2001-08-01

    Water vapour concentration is one of the most important, yet one of the least known quantities of the mesosphere. Knowledge of water vapour concentration is the key to understanding many mesospheric processes, including the one that is primary focus of our investigation, mesospheric clouds (MC). The processes of formation and occurrence parameters of MC constitute an interesting problem in their own right, but recently evidence has been provided which suggests that they are a critical indicator of atmospheric change. The aim of the SALI-AT experiment is to make simultaneous (although not strictly collocated) measurements of water vapour, aerosols and temperature in the mesosphere and the mesopause region under twilight condition in the presence of mesospheric clouds. The water vapour will be measured in the regime of solar occultation utilizing a water vapour absorption band at 936 nm wavelength employing the SALI (Spectral Absorption Line Imager) instrument concept. A three-channel zenith photometer, AT-3, with wavelengths of 385 nm, 525 nm, and 1040 nm will measure Mie and Rayleigh scattering giving both mesospheric temperature profiles and the particle size distribution. Both instruments are small, low cost and low mass. It is envisioned that the SALI-AT experiment be flown on a small rocket - the Improved Orion/Hotel payload configuration, from the Andoya Rocket range, Norway. Alternatively the instrument can be flown as a "passenger" on larger rocket carrying other experiments. In either case flight costs are relatively low. Some performance simulations are presented showing that the instrument we have designed will be sufficiently sensitive to measure water vapor in concentrations that are expected at the summer mesopause, about 85 km height.

  11. [Study on oral absorption enhancers of astragalus polysaccharides].

    PubMed

    Chen, Xiao-Yun; Tan, Xiao-Bin; Sun, E; Liu, Dan; Jia, Xiao-Bin; Zhang, Zhen-Hai

    2014-04-01

    Astragalus polysaccharides was lounded to 4-(2-aminoethylphenol), followed by labeling the APS-Tyr with fluorescein-5-isothiocyanate (FITC) at the secondary amino group. The absorption enhancement effects of low molecular weight chitosan and protamine on astragalus polysaccharides were evaluated via Caco-2 cell culture model. The results show that the fluorecent labeling compound has good stability and high sensitivity. On the other hand low molecular weight chitosan and protamine also can promoted absorption of the astragalus polysaccharides without any cytotoxity, and the absorption increase was more significant with increasing the amount of low molecular weight chitosan and protamine. At the same time, the low molecular weight chitosan has slightly better effect. The transepithelial electric resistance (TEER) of Caco-2 cells show that absorption enhancers could improve its membrane transport permeability by opening tight junctions between cells and increasing the cell membrane fluidity.

  12. Povidone iodine skin absorption: an ex-vivo study.

    PubMed

    Nesvadbova, Martina; Crosera, Matteo; Maina, Giovanni; Larese Filon, Francesca

    2015-06-15

    Povidone iodine is a water-soluble complex used to disinfect the skin surface and it exerts prolonged germicidal action against a broad spectrum of germs. Indeed, it is often applied on burned skin, large wounds, deep tissues or mucosa. Notably some surgical hand-scrub solutions, which are considered safe antiseptics, contain large amounts of iodine that can be absorbed by skin. The aim of present study was to study the skin absorption of iodine after the application on the skin of povidone-iodine solution, used by health care workers during surgical procedure. We use Franz diffusion static cells with human skin. After 24h from the beginning of our measurement the iodine concentration in the receiving compartment was 11.59±6.3μg/cm(2). The medium flux calculated was 0.73±0.33μg/cm(2)/h with a lag time of 8.9±1.5h. These in vitro results confirmed that povidone iodine could pass through the skin in a relevant amount that can explain the clinical findings in burned or surgically treated patients. In professional use the repetitive contact with povidone iodine, also as soap, can cause iodine skin permeation that must be considered when the washing procedures are repeated more than 20 times a day.

  13. Povidone iodine skin absorption: an ex-vivo study.

    PubMed

    Nesvadbova, Martina; Crosera, Matteo; Maina, Giovanni; Larese Filon, Francesca

    2015-06-15

    Povidone iodine is a water-soluble complex used to disinfect the skin surface and it exerts prolonged germicidal action against a broad spectrum of germs. Indeed, it is often applied on burned skin, large wounds, deep tissues or mucosa. Notably some surgical hand-scrub solutions, which are considered safe antiseptics, contain large amounts of iodine that can be absorbed by skin. The aim of present study was to study the skin absorption of iodine after the application on the skin of povidone-iodine solution, used by health care workers during surgical procedure. We use Franz diffusion static cells with human skin. After 24h from the beginning of our measurement the iodine concentration in the receiving compartment was 11.59±6.3μg/cm(2). The medium flux calculated was 0.73±0.33μg/cm(2)/h with a lag time of 8.9±1.5h. These in vitro results confirmed that povidone iodine could pass through the skin in a relevant amount that can explain the clinical findings in burned or surgically treated patients. In professional use the repetitive contact with povidone iodine, also as soap, can cause iodine skin permeation that must be considered when the washing procedures are repeated more than 20 times a day. PMID:25858112

  14. The Hubble Space Telescope Quasar Absorption Line Key Project. 10: Galactic H I 21 centimeter emission toward 143 quasars and active Galactic nuclei

    NASA Technical Reports Server (NTRS)

    Lockman, Felix J.; Savage, Blair D.

    1995-01-01

    Sensitive H I 21 cm emission line spectra have been measured for the directions to 143 quasars and active galactic nuclei (AGNs) chosen from the observing lists for the Hubble Space Telescope (HST) Quasar Absorption Line Key Project. Narrow-band and wide-band data were obtained with the National Radio Astronomy Observatory (NRAO) 43 m radio telescope for each object. The narrow-band data have a velocity resolution of 1 km/s, extend from -220 to +170 km/s, and are corrected for stray 21 cm radiation. The wide-band data have a resolution of 4 km/s and extend from -1000 to +1000 km/s. The data are important for the interpretation of ultraviolet absorption lines near zero redshift in Key Project spectra. Twenty-two percent of the quasars lie behind Galactic high-velocity H I clouds with absolute value of V(sub LSR) greater than 100 km/s whose presence can increase the equivalent width of interstellar absorption lines significantly. This paper contains the emission spectra and measures of the H I velocities and column densities along the sight line to each quasar. We discuss how the measurements can be used to estimate the visual and ultraviolet extinction toward each quasar and to predict the approximate strength of the strong ultraviolet resonance lines of neutral gas species in the HST Key Project spectra.

  15. [Study of retrieving formaldehyde with differential optical absorption spectroscopy].

    PubMed

    Li, Yu-Jin; Xie, Pin-Hua; Qin, Min; Qu, Xiao-Ying; Hu, Lin

    2009-01-01

    The present paper introduces the method of retrieving the concentration of HCHO with differential optical absorption spectroscopy (DOAS). The authors measured ambient HCHO in Beijing region with the help of differential optical absorption spectroscopy instrument made by ourself, and discussed numerous factors in retrieving the concentration of HCHO with differential optical absorption spectroscopy (DOAS), especially, the choice of HCHO wave band, how to avoid absorption of ambient SO2, NO2 and O3, and the influence of the Xenon lamp spectrum structure on the absorption of ambient HCHO. The authors achieved the HCHO concentration by simultaneously retrieving the concentrations of HCHO, SO2, NO2 and O3 with non-linear least square fitting method, avoiding the effect of choosing narrow wave of HCHO and the residual of SO2, NO2, O3 and the Xenon lamp spectrum structure in retrieving process to attain the concentration of HCHO, Finally the authors analyzed the origin of error in retrieving the concentration of HCHO with differential optical absorption spectroscopy (DOAS), and the total error is within 13.7% in this method. PMID:19385238

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  17. Nonlinear intersubband absorption of a hot quasi-two-dimensional electron plasma studied by femtosecond infrared spectroscopy

    SciTech Connect

    Lutgen, S.; Kaindl, R.A.; Woerner, M.; Elsaesser, T.; Hase, A.; Kuenzel, H.

    1996-12-01

    The transient ({ital n}=1) to ({ital n}=2) intersubband absorption of a pure electron plasma in {ital n}-type Ga{sub 0.48}In{sub 0.53}As/Al{sub 0.48}In{sub 0.52}As quantum wells is studied in femtosecond pump-probe experiments. The ultrafast dynamics of nonlinear absorption shows strong changes when tuning the midinfrared pulses over the intersubband absorption line. The nonlinear optical response is determined by both intersubband relaxation with a time constant of 1.3 ps and the intraband dynamics of ({ital n}=1) electrons, which are monitored in an independent experiment. {copyright} {ital 1996 The American Physical Society.}

  18. An automated on-line minicolumn preconcentration cold vapour atomic absorption spectrometer: application to determination of cadmium in water samples.

    PubMed

    Sahan, Serkan; Sahin, Uğur

    2012-01-15

    A method was developed for on-line solid phase preconcentration and cold vapour atomic absorption spectrometric determination of Cd(II) in aqueous samples. Lewatit Monoplus TP207 iminodiacetate chelating resin was used for the separation and preconcentration of Cd(II) ions at pH 4.0. The whole system was labmade. The influence of analytical parameters such as concentration of eluent and sodium tetrahydroborate solution, flow rate of eluent, sample, and Ar, and matrix ions were investigated. A preconcentration factor of 20 and a detection limit (3s(b)) of 2.1ngL(-1), along with a sampling frequency of 28h(-1) were achieved with 1.4min of sample loading time and with 2.8mL sample consumption. The relative standard deviation (R.S.D.) was 2.5% for 0.05μgL(-1) Cd(II) level. The developed method was used for Cd(II) analysis in water samples. The certified reference material (LGC6019) experimental results are in good agreement with the certified value.

  19. The Hubble Space Telescope quasar absorption line key project. v. redshift evolution of lyman limit absorption in the spectra of a large sample of quasars

    NASA Technical Reports Server (NTRS)

    Stengler-Larrea, Erik A.; Boksenberg, Alec; Steidel, Charles, C.; Sargent, W. L. W.; Bacall, John N.; Bergeron, Jacqueline; Hartig, George F.; Jannuzi, Buell T.; Kirhakos, Sofia; Savage, Blair D.

    1995-01-01

    Using a sample of 119 QSOs, containing objects we have selected having previously available high quality ground-based and IUE spectral observations, together with Hubble Space Telescope (HST) observations of 26 QSOs from Bahcall et al. (1993, 1995) and Impey et al. (1995) and new optical observations of 41 objects by Steidel & Sargent (1995), we study the redshift evolution of Lyman limit absorption systems (LLSs; tau greater than 1.0) over the reshift range 0.32 less than or equal to z(sub LLS) less than or equal to 4.11. The HST observations significantly improve the determination of the low redshift (0.4 less than or equal to z(sub LLS) less than or equal to 1.4) distribution. We find the effect which may have been responsible for the apparent strong evolution at a(sub LLS) greater than or equal to 2.5 found by Lanzetta (1991), which led him to consider a broken, not single power law as a better description of the redshift distribution of LLSs. After removing objects which may bias our sample, leaving a total of 169 QSOs, we find the distribution is well described by a single power law, and obtain for the number density as a function of redshift the form N(z) = N(sub 0)(1 + z)(exp gamma) with gamma = 1.50 =/- 0.39 and N(sub 0) = 0.25(sup -0.10)(sub +0.17), consistent with a constant comoving density of absorbers in a Firedmann universe with q(sub 0) = 0 but indicating evolution if q(sub 0) = 1/2.

  20. Light Scattering and Absorption Studies of Sickle Cell Hemoglobin

    NASA Astrophysics Data System (ADS)

    Kim-Shapiro, Daniel

    1997-11-01

    The use of physical techniques has been very important in understanding the pathophysiology of sickle cell disease. In particular, light scattering and absorption studies have been used to measure the kinetics of sickle cell hemoglobin polymerization and depolymerization (melting). The theory of sickle cell polymerization that has been derived and tested by these methods has not only led to an increased understanding of the pathophysiology of the disease but has also led to improved treatment strategies. Sickle cell disease effects about 1 out of 600 people of African descent born in the United States. The disease is caused by a mutant form of hemoglobin (the oxygen transporting molecule in the blood), hemoglobin S (HbS), which differs from normal adult hemoglobin by the substitution of a single amino acid for another. The polymerization of HbS, which occurs under conditions of low oxygen pressure, causes distortion and increased rigidity of the sickle red blood cell that leads to blockage of the capillaries and a host of resulting complications. The disease is associated with tissue damage, severe painful crises and a high degree of mortality. Light scattering studies of purified HbS and whole cells (conducted by F.A. Ferrone, J. Hofrichter, W.A. Eaton, and their associates) have been used to determine the mechanism of HbS polymerization. Polymerization will generally not occur when the hemoglobin is in an oxygen-rich environment. The question is, when HbS is rapidly deoxygenated (as it is when going from the lungs to the tissues) what is the kinetics of polymerization? Photolysis methods were used to rapidly deoxygenate HbS and light scattering was used as a function of time to measure the kinetics of polymerization. Polarized light scattering may be a more effective way to measure polymer content than total intensity light scattering. It was found that no polymerization occurs during a period of time called the delay time and subsequent polymerization occurs

  1. Measurements of the absorption line strength of hydroperoxyl radical in the ν3 band using a continuous wave quantum cascade laser.

    PubMed

    Sakamoto, Yosuke; Tonokura, Kenichi

    2012-01-12

    Mid-infrared absorption spectroscopy has been applied to the detection of the hydroperoxyl (HO(2)) radical in pulsed laser photolysis combined with a laser absorption kinetics reactor. Transitions of the ν(3) vibrational band assigned to the O-O stretch mode were probed with a thermoelectrically cooled, continuous wave mid-infrared distributed feedback quantum cascade laser (QCL). The HO(2) radicals were generated with the photolysis of Cl(2)/CH(3)OH/O(2) mixtures at 355 nm. The absorption cross section at each pressure was determined by three methods at 1065.203 cm(-1) for the F(1), 13(1,13) ← 14(1,14) transition in the ν(3) band. From these values, the absolute absorption cross section at zero pressure was estimated. The relative line strengths of other absorptions in the feasible emitting frequency range of the QCL from 1061.17 to 1065.28 cm(-1) were also measured, and agreed with values reproduced from the HITRAN database. The ν(3) band absorption strength was estimated from the analytically obtained absolute absorption cross section and the calculated relative intensity by spectrum simulation, to be 21.4 ± 4.2 km mol(-1), which shows an agreement with results of quantum chemical calculations. PMID:22148191

  2. Measurements of the absorption line strength of hydroperoxyl radical in the ν3 band using a continuous wave quantum cascade laser.

    PubMed

    Sakamoto, Yosuke; Tonokura, Kenichi

    2012-01-12

    Mid-infrared absorption spectroscopy has been applied to the detection of the hydroperoxyl (HO(2)) radical in pulsed laser photolysis combined with a laser absorption kinetics reactor. Transitions of the ν(3) vibrational band assigned to the O-O stretch mode were probed with a thermoelectrically cooled, continuous wave mid-infrared distributed feedback quantum cascade laser (QCL). The HO(2) radicals were generated with the photolysis of Cl(2)/CH(3)OH/O(2) mixtures at 355 nm. The absorption cross section at each pressure was determined by three methods at 1065.203 cm(-1) for the F(1), 13(1,13) ← 14(1,14) transition in the ν(3) band. From these values, the absolute absorption cross section at zero pressure was estimated. The relative line strengths of other absorptions in the feasible emitting frequency range of the QCL from 1061.17 to 1065.28 cm(-1) were also measured, and agreed with values reproduced from the HITRAN database. The ν(3) band absorption strength was estimated from the analytically obtained absolute absorption cross section and the calculated relative intensity by spectrum simulation, to be 21.4 ± 4.2 km mol(-1), which shows an agreement with results of quantum chemical calculations.

  3. Determination of cobalt in biological samples by line-source and high-resolution continuum source graphite furnace atomic absorption spectrometry using solid sampling or alkaline treatment

    NASA Astrophysics Data System (ADS)

    Ribeiro, Anderson Schwingel; Vieira, Mariana Antunes; da Silva, Alessandra Furtado; Borges, Daniel L. Gallindo; Welz, Bernhard; Heitmann, Uwe; Curtius, Adilson José

    2005-06-01

    Two procedures for the determination of Co in biological samples by graphite furnace atomic absorption spectrometry (GF AAS) were compared: solid sampling (SS) and alkaline treatment with tetramethylammonium hydroxide (TMAH) using two different instruments for the investigation: a conventional line-source (LS) atomic absorption spectrometer and a prototype high-resolution continuum source atomic absorption spectrometer. For the direct introduction of the solid samples, certified reference materials (CRM) were ground to a particle size ≤50 μm. Alkaline treatment was carried out by placing about 250 mg of the sample in polypropylene flasks, adding 2 mL of 25% m/v tetramethylammonium hydroxide and de-ionized water. Due to its unique capacity of providing a 3-D spectral plot, a high-resolution continuum source (HR-CS) graphite furnace atomic absorption spectrometry was used as a tool to evaluate potential spectral interferences, including background absorption for both sample introduction procedures, revealing that a continuous background preceded the atomic signal for pyrolysis temperatures lower than 700 °C. Molecular absorption bands with pronounced rotational fine structure appeared for atomization temperatures >1800 °C probably as a consequence of the formation of PO. After optimization had been carried out using high resolution continuum source atomic absorption spectrometry, the optimized conditions were adopted also for line-source atomic absorption spectrometry. Six biological certified reference materials were analyzed, with calibration against aqueous standards, resulting in agreement with the certified values (according to the t-test for a 95% confidence level) and in detection limits as low as 5 ng g -1.

  4. Smile line and occlusion: An epidemiological study

    PubMed Central

    Harati, Mahsa; Mostofi, Shahbaz Naser; Jalalian, Ezzatollah; Rezvani, Gholamreza

    2013-01-01

    Background: The purpose of the present study was to discuss some new concepts of the desirable characteristics of smile tooth display. Due to the increasing application of cosmetic dental treatments, there is an increasing need for better understanding of the esthetic principles. Materials and Methods: In the present descriptive study, with 212 participants, included were patients with no history of orthodontic treatment, loss or prosthetic replacement of anterior teeth, extracted teeth, lips with asymmetry or a history of trauma. Chi-square test was used to determine possible significances in the relation of smile line to Angle occlusion class, overbite and overjet and arch form. A P level of <0.05 was set as to be significant. Results: Chi-square test indicated that there was a significant difference between the smile design and overbite, overjet and gender but no statistically significant association was found between the smile design and crossbite, molar Angle classification and arch form. Conclusion: Within the limitations of such studies, it might be concluded that there is a significant and important relation between some occlusal parameters and smile design, which must be considered. PMID:24379858

  5. Theoretical Study of New Combined Absorption-Ejector Refrigeration System

    NASA Astrophysics Data System (ADS)

    Abed, A. M.; Sopian, K.; Alghoul, M. A.; Al-Shamani, A. N.; Ruslan, M. H.; Mat, S.

    2015-09-01

    An improved system of the new combined single stage absorption cycle operated with NH3/H2O as working fluid was performed. In order to enhance performance the cycle a new configuration of absorption system was utilized. The performances of two configurations of the combined absorption cycle were compared; a) with common solution heat exchanger and b) divided the streamline of solution heat exchanger to recover the internal heat. Based on the analysis, it has been shown that the second configuration a significant reduction of the required generator and absorber loads by about 20% and 17% respectively, with increased coefficient of performance (COP) about 12% compared to the first configuration. This improvement in the overall COP is found due to improve energy utilization efficiency significantly.

  6. Neuron absorption study and mid-IR optical excitations

    NASA Astrophysics Data System (ADS)

    Guo, Dingkai; Chen, Xing; Vadala, Shilpa; Leach, Jennie; Kostov, Yordan; Bewley, William W.; Kim, Chul-Soo; Kim, Mijin; Canedy, Chadwick L.; Merritt, Charles D.; Vurgaftman, Igor; Meyer, Jerry R.; Choa, Fow-Sen

    2012-02-01

    Neuronal optical excitation can provide non-contacting tools to explore brain circuitry and a durable stimulation interface for cardiac pacing and visual as well as auditory sensory neuronal stimulation. To obtain accurate absorption spectra, we scan the transmission of neurons in cell culture medium, and normalize it by subtracting out the absorption spectrum of the medium alone. The resulting spectra show that the main neuronal absorption peaks are in the 3000- 6000nm band, although there is a smaller peak near 1450nm. By coupling the output of a 3μm interband cascade laser (ICL) into a mid-IR fluorozirconate fiber, we can effectively deliver more than 1J/cm2 photon intensity to the excitation site for neuronal stimulation.

  7. Study on moisture absorption and sweat discharge of honeycomb polyester fiber

    NASA Astrophysics Data System (ADS)

    Feng, Aifen; Zhang, Yongjiu

    2015-07-01

    The moisture absorption and liberation properties of honeycomb polyester fiber were studied in order to understand its moisture absorption and sweat discharge. Through testing moisture absorption and liberation regains of honeycomb polyester fiber and normal polyester fiber in standard atmospheric conditions, their moisture absorption and liberation curves were depicted, and the regression equations of moisture regains to time during their reaching the balance of moisture absorption and moisture liberation were obtained according to the curves. Their moisture absorption and liberation rate curves were analyzed and the regression equations of the rates to time were obtained. The results shows that the moisture regain of honeycomb polyester fiber is much bigger than the normal polyester fiber's, and the initial moisture absorption and moisture liberation rates of the former are much higher than the latter's, so that the moisture absorbance and sweat discharge of honeycomb polyester fiber are excellent.

  8. High Signal-to-Noise Echelle Spectroscopy of Quasar Absorption-Line Systems in the Direction of HS 1946+7658

    NASA Astrophysics Data System (ADS)

    Tripp, Todd M.; Lu, Limin; Savage, Blair D.

    1996-02-01

    We have obtained a high signal-to-noise (40 <= S/N <= 80) high- resolution (FWHM = 20 km s^-1^) spectrum of the radio-quiet QSO HS 1946+7658 (z_em_ = 3.051) with the echelle spectrograph on the KPNO 4 m telescope. We detect 11 metal systems in the direction of this QSO, including two Mg II systems, five C IV systems, two damped Lyα systems, and two associated systems. We use the apparent column density technique and profile fitting to measure the heavy element column densities and to assess the effects of absorption-line saturation. Profile fitting indicates that three of the C IV systems are narrow with b < 8 km s^-1^. This implies that T < 50,000 K, and therefore these systems are probably photoionized. The abundance patterns in the damped Lyα systems are strikingly similar to those observed in low- metallicity Milky Way stars and suggest that these absorption lines are due to galaxies in early stages of chemical enrichment (see Lu et al.). The prominent associated system at z_abs_ = 3.0496,3.0504 is detected in H I, C II, CIV, SiII, Si III, Si IV, A1 II, Al III, and N V. The high ion column density ratios in this associated system imply that the gas is more highly ionized than the Galactic halo. The high degree of ionization is not surprising given the extraordinary luminosity of the QSO (Hagen et al.). To study ionization and abundances in this associated system, we compare the observed column densities to a series of CLOUDY models in which photoionization by the QSO is the dominant ionization mechanism. For the input radiation field, we have used the various spectral energy distributions of HS 1946+7658 observed by Kuhn et al. The model that best fits the observed column densities of singly and doubly ionized species has solar relative and absolute abundances, but models with absolute metallicities a few times greater than solar fit comparably well. None of the models produce enough Si IV and C IV, but the QSO flux near the ionization potentials of these

  9. Laser line illumination scheme allowing the reduction of background signal and the correction of absorption heterogeneities effects for fluorescence reflectance imaging.

    PubMed

    Fantoni, Frédéric; Hervé, Lionel; Poher, Vincent; Gioux, Sylvain; Mars, Jérôme I; Dinten, Jean-Marc

    2015-10-01

    Intraoperative fluorescence imaging in reflectance geometry is an attractive imaging modality as it allows to noninvasively monitor the fluorescence targeted tumors located below the tissue surface. Some drawbacks of this technique are the background fluorescence decreasing the contrast and absorption heterogeneities leading to misinterpretations concerning fluorescence concentrations. We propose a correction technique based on a laser line scanning illumination scheme. We scan the medium with the laser line and acquire, at each position of the line, both fluorescence and excitation images. We then use the finding that there is a relationship between the excitation intensity profile and the background fluorescence one to predict the amount of signal to subtract from the fluorescence images to get a better contrast. As the light absorption information is contained both in fluorescence and excitation images, this method also permits us to correct the effects of absorption heterogeneities. This technique has been validated on simulations and experimentally. Fluorescent inclusions are observed in several configurations at depths ranging from 1 mm to 1 cm. Results obtained with this technique are compared with those obtained with a classical wide-field detection scheme for contrast enhancement and with the fluorescence by an excitation ratio approach for absorption correction. PMID:26442963

  10. Enhanced oral absorption of insulin-loaded liposomes containing bile salts: a mechanistic study.

    PubMed

    Niu, Mengmeng; Tan, Ya'nan; Guan, Peipei; Hovgaard, Lars; Lu, Yi; Qi, Jianping; Lian, Ruyue; Li, Xiaoyang; Wu, Wei

    2014-01-01

    Liposomes containing bile salts (BS-liposomes) significantly enhanced the oral bioavailability of insulin (rhINS). However, the underlying absorption mechanisms have not been well understood yet. In this study, the transiting fate of the liposomes was first investigated using fluorescent imaging tools to confirm the effect of enhanced gastrointestinal stability. In order to obtain evidence of enhanced transcellular permeation, the interaction between BS-liposomes and the biomembrane was investigated in Caco-2 cell lines. BS-liposomes were found to be more stable in the gastrointestinal tract by showing prolonged residence time in comparison with conventional liposomes. BS-liposomes were significantly more effective for cellular uptake and transport of rhINS; and this effect was found to be size- and concentration-dependent. A good linear correlation was observed between the concentration of the liposomes and uptake/transport of rhINS. Confocal laser scanning microscopy visualization further validated the transcellular transit of BS-liposomes. The BS-liposomes showed little effect on cytotoxicity and did not induce apoptosis within 24h investigation. It was concluded that BS-liposomes showed improved in vivo residence time and enhanced permeation across the biomemebranes. Mechanisms of trans-enterocytic internalization could be proposed as an interpretation for enhanced absorption of insulin-loaded liposomes.

  11. THE STELLAR INITIAL MASS FUNCTION IN EARLY-TYPE GALAXIES FROM ABSORPTION LINE SPECTROSCOPY. I. DATA AND EMPIRICAL TRENDS

    SciTech Connect

    Van Dokkum, Pieter G.; Conroy, Charlie

    2012-11-20

    The strength of gravity-sensitive absorption lines in the integrated light of old stellar populations is one of the few direct probes of the stellar initial mass function (IMF) outside of the Milky Way. Owing to the advent of fully depleted CCDs with little or no fringing it has recently become possible to obtain accurate measurements of these features. Here, we present spectra covering the wavelength ranges 0.35-0.55 {mu}m and 0.72-1.03 {mu}m for the bulge of M31 and 34 early-type galaxies from the SAURON sample, obtained with the Low Resolution Imaging Spectrometer on Keck. The signal-to-noise ratio is {approx}> 200 A{sup -1} out to 1 {mu}m, which is sufficient to measure gravity-sensitive features for individual galaxies and to determine how they depend on other properties of the galaxies. Combining the new data with previously obtained spectra for globular clusters in M31 and the most massive elliptical galaxies in the Virgo cluster, we find that the dwarf-sensitive Na I {lambda}8183, 8195 doublet and the FeH {lambda}9916 Wing-Ford band increase systematically with velocity dispersion, while the giant-sensitive Ca II {lambda}8498, 8542, 8662 triplet decreases with dispersion. These trends are consistent with a varying IMF, such that galaxies with deeper potential wells have more dwarf-enriched mass functions. In a companion paper, we use a comprehensive stellar population synthesis model to demonstrate that IMF effects can be separated from age and abundance variations and quantify the IMF variation among early-type galaxies.

  12. In vitro study of transporters involved in intestinal absorption of inorganic arsenic.

    PubMed

    Calatayud, Marta; Barrios, Julio A; Vélez, Dinoraz; Devesa, Vicenta

    2012-02-20

    Inorganic arsenic (iAs) [As(III)+As(V)] is a drinking water contaminant, and human exposure to these arsenic species has been linked with a wide range of health effects. The main path of exposure is the oral route, and the intestinal epithelium is the first physiological barrier that iAs must cross in order to be absorbed. However, there is a lack of information about intestinal iAs absorption. The aim of this study was to evaluate the participation of certain transporters [glucose transporters (GLUT and SGLT), organic anion transporting polypeptides (OATPs), aquaporins (AQPs), and phosphate transporters (NaPi and PiT)] in intestinal absorption of As(V) and As(III), using the Caco-2 cell line as a model of the intestinal epithelium. For this purpose, the effects of chemical inhibition and gene silencing of the transporters of interest on iAs uptake were evaluated, and also the differential expression of these transporters after treatment with iAs. The results show that chemical inhibition using rifamycin SV (OATP inhibitor), phloridzin (SGLT inhibitor), phloretin (GLUT and AQP inhibitor), and copper sulfate (AQP inhibitor) leads to a significant reduction in the apparent permeability and cellular retention of As(III). RT-qPCR indicates up-regulation of GLUT2, GLUT5, OATPB, AQP3, and AQP10 after exposure to As(III), while exposure to As(V) increases the expression of sodium-dependent phosphate transporters, especially NaPiIIb. Gene silencing of OATPB, AQP10, and GLUT5 for As(III) and NaPiIIb for As(V) significantly reduces uptake of the inorganic forms. These results indicate that these transporters may be involved in intestinal absorption of iAs.

  13. Studies on the absorption of sodium and chloride from the rumen of sheep.

    PubMed

    Martens, H; Blume, I

    1987-01-01

    The net absorption of Na and Cl from the temporarily isolated rumen of sheep was studied using an artificial ruminal fluid with different Na and K and constant Cl concentrations. The net absorption of Na and Cl was linearly correlated. The net absorption of Cl was abolished and a small net secretion was observed when no sodium was in the artificial rumen fluid. The net absorption of Na was significantly reduced under chloride free conditions. It is concluded that the active transport of Na and Cl is coupled. The mechanism of an Na-Cl cotransport can not be deduced from these studies.

  14. On-line sequential injection dispersive liquid-liquid microextraction system for flame atomic absorption spectrometric determination of copper and lead in water samples.

    PubMed

    Anthemidis, Aristidis N; Ioannou, Kallirroy-Ioanna G

    2009-06-30

    A simple, sensitive and powerful on-line sequential injection (SI) dispersive liquid-liquid microextraction (DLLME) system was developed as an alternative approach for on-line metal preconcentration and separation, using extraction solvent at microlitre volume. The potentials of this novel schema, coupled to flame atomic absorption spectrometry (FAAS), were demonstrated for trace copper and lead determination in water samples. The stream of methanol (disperser solvent) containing 2.0% (v/v) xylene (extraction solvent) and 0.3% (m/v) ammonium diethyldithiophosphate (chelating agent) was merged on-line with the stream of sample (aqueous phase), resulting a cloudy mixture, which was consisted of fine droplets of the extraction solvent dispersed entirely into the aqueous phase. By this continuous process, metal chelating complexes were formed and extracted into the fine droplets of the extraction solvent. The hydrophobic droplets of organic phase were retained into a microcolumn packed with PTFE-turnings. A portion of 300 microL isobutylmethylketone was used for quantitative elution of the analytes, which transported directly to the nebulizer of FAAS. All the critical parameters of the system such as type of extraction solvent, flow-rate of disperser and sample, extraction time as well as the chemical parameters were studied. Under the optimum conditions the enhancement factor for copper and lead was 560 and 265, respectively. For copper, the detection limit and the precision (R.S.D.) were 0.04 microg L(-1) and 2.1% at 2.0 microg L(-1) Cu(II), respectively, while for lead were 0.54 microg L(-1) and 1.9% at 30.0 microg L(-1) Pb(II), respectively. The developed method was evaluated by analyzing certified reference material and applied successfully to the analysis of environmental water samples. PMID:19376348

  15. UV Absorption Lines as Metallicity Estimator and the Metal Content of Star-forming Galaxies at z=5

    NASA Astrophysics Data System (ADS)

    Faisst, Andreas; Capak, Peter L.; Davidson, Iary; Kakazu, Yuko; Salvato, Mara; Laigle, Clotilde; Onodera, Masato; Masters, Daniel; COSMOS Team

    2016-01-01

    Probing the metal content of high redshift galaxies is essential to study their formation and evolution in the early universe. However, the spectral features used to measure the metallicity are shifted out of the wavelength range of current spectrographs at high-z and therefore alternative methods must be used.We measure the relation between four prominent UV absorption complexes and metallicity for more than 50 local galaxies and, by using a sample of more than 20 galaxies at z ~ 2 - 3, verify that this relation holds up to z ˜ 3. We then apply this method to a sample of ˜ 220 galaxies at 3.5 < z < 6.0 in COSMOS, for which unique UV spectra from DEIMOS and accurate stellar mass estimates from SPLASH are available. The z ~ 5 galaxies at 9 < log(m/M⊙) < 11 are characterized by 0.3 - 0.4 dex (in units of 12 + log(O/H)) lower metallicities than galaxies at z ˜ 2 but comparable to z ˜ 3 - 3.5 galaxies. In the same stellar mass range, we do not find a significant relation between stellar mass and metallicity (MZ relation), suggesting that the MZ relation at z ~ 5 is very shallow or breaking down. Since we verify a correlation between dust obscuration (measured by β) and UV absorption strength (i.e., metallicity), we argue that the process of dust production and metal enrichment in the first billion years of galaxy formation is more stochastic than at later times. Using a "bathtub" model approach, we find that an exponential build up of stellar mass within a short time of several 100 Myr can explain a shallow MZ relation at z ˜ 5. Furthermore, we find a weak anti-correlation between star-formation rates and UV absorption strength (i.e., metallicity), indicative of these galaxies being fueled by the inflow of pristine (metal-poor) gas. The galaxy sample presented in this work is unique to further test these scenarios using ALMA and the upcoming James Webb Space Telescope.

  16. [Study on intestinal absorption of ingredients from different compatibilities of Shaoyao Gancao decoction].

    PubMed

    Ma, Ting-ting; He, Rui; Gong, Mu-xin; Xu, Yong-song; Li, Jing; Zhai, Yong-song; Wan, Guang

    2015-11-01

    To study the compatible mechanisms and compatible proportion of Shaoyao Gancao decoction, the intestinal absorption of main ingredients in Shaoyao Gancao decoction SG11 (Baishao-Zhigancao 1: 1) , SG31 (Baishao-Zhigancao 3: 1), Baishao water decoction S and Zhigancao (G) were investigated and compared using in vitro everted intestinal sac model and in situ single pass intestinal perfusion (SPIP) model. The concentration of paeoniflorin (PF), liquiritin (LQ) and mono-ammonium glycyrrhizinate (GL) in test samples and samples of intestinal sac and intestinal perfusion was determined by HPLC. The intestinal absorptive amount and absorption parameters were calculated. Results showed that in the everted intestinal sac model, three ingredients could be absorbed by duodenum, jejunum and ileum, and the absorption in the jejunum was best for all 3 ingredients. The absorption rate of three ingredients in SG11 was significantly higher than that in single decoction (P < 0.05), but had no significant difference compared with SG31. In SPIP model, the absorption rate constant K(a), the apparent absorption coefficient P(app) and the absorption rate of three ingredients in SG11 were significantly higher than those in single decoction. Parameters of PF and GL in SG11 were significantly higher than those in SG31, but had no differences of LQ. It proved that the compatibility of Baishao and Zhigancao could improve the intestinal absorption of PF, LQ and GL. The absorption of each ingredient in SG11 was better than that in SG31.

  17. Infrared band absorptance correlations and applications to nongray radiation. [mathematical models of absorption spectra for nongray atmospheres in order to study air pollution

    NASA Technical Reports Server (NTRS)

    Tiwari, S. N.; Manian, S. V. S.

    1976-01-01

    Various mathematical models for infrared radiation absorption spectra for atmospheric gases are reviewed, and continuous correlations for the total absorptance of a wide band are presented. Different band absorptance correlations were employed in two physically realistic problems (radiative transfer in gases with internal heat source, and heat transfer in laminar flow of absorbing-emitting gases between parallel plates) to study their influence on final radiative transfer results. This information will be applied to the study of atmospheric pollutants by infrared radiation measurement.

  18. Photoinduced Absorption and Transient Grating Studies of Conjugated Polymers.

    NASA Astrophysics Data System (ADS)

    Spiegel, Daniel Richard

    Most of the attributes that make conjugated polymers theoretically and technologically interesting derive from the electronic properties of the excited states. The well -known models which have successfully explained many of the solid state properties of these systems have emphasized the coupling of the electronic structure and the underlying lattice. Recently, it has become possible to obtain conjugated polymers in solution. In these systems, there exists an important parameter which is quenched in the solid state; namely, the entropy associated with the many different configurations in which a chain may exist. It becomes important, therefore, to examine to what extent the models that describe electronic processes in solid state conjugated polymers may be extended to solutions. Such questions are intimately tied to the macromolecular conformation favored by dissolved conjugated chains. In this thesis, soluble conjugated polymers are investigated using two CW pump-and-probe optical techniques. Both the solution and solid states have been investigated. First, results of spectroscopic CW resonant photoinduced absorption (PA) studies show that bipolarons are the preferred excitation for the storage of charge added via photoexcitation in thin films of poly(3-alkylthiophenes) (P3ATs). Additionally, resonant PA has also been carried out successfully in solutions of P3ATs dissolved in several different solvents. Based on the similarity of the photoinduced spectra in the solution and the solid state, it is concluded that bipolarons remain the preferred excitation in P3AT solutions. The dependences of the photoinduced signal on pump intensity, modulation frequency, and, in the case of solutions, polymer concentration are also reported. Secondly, two coherent crossed pump beams are used to create transient gratings within P3AT solutions, with excited states on the chains providing the optical contrast. The grating decay, after the pump beams are shut off, is monitored

  19. Study of band inversion in the PbxSn1-xTe class of topological crystalline insulators using x-ray absorption spectroscopy.

    PubMed

    Mitrofanov, K V; Kolobov, A V; Fons, P; Krbal, M; Tominaga, J; Uruga, T

    2014-11-26

    Pb(x)Sn(1-x)Te and Pb(x)Sn(1-x)Se crystals belong to the class of topological crystalline insulators where topological protection is achieved due to crystal symmetry rather than time-reversal symmetry. In this work, we make use of selection rules in the x-ray absorption process to experimentally detect band inversion along the PbTe(Se)-SnTe(Se) tie-lines. The observed significant change in the ratio of intensities of L1 and L3 transitions along the tie-line demonstrates that x-ray absorption can be a useful tool to study band inversion in topological insulators.

  20. Total Absorption Study of Beta Decays Relevant for Nuclear Applications and Nuclear Structure

    SciTech Connect

    Algora, A.; Valencia, E.; Taín, J.L.; Jordan, M.D.; Agramunt, J.; Rubio, B.; Estevez, E.; Molina, F.; Montaner, A.; Guadilla, V.; Fallot, M.; Porta, A.; Zakari-Issoufou, A.-A.; Bui, V.M.; and others

    2014-06-15

    An overview is given of our activities related to the study of the beta decay of neutron rich nuclei relevant for nuclear applications. Recent results of the study of the beta decay of {sup 87,88}Br using a new segmented total absorption spectrometer are presented. The measurements were performed at the IGISOL facility using trap-assisted total absorption spectroscopy.

  1. Total Absorption Study of Beta Decays Relevant for Nuclear Applications and Nuclear Structure

    SciTech Connect

    Algora, A.; Valencia, E.; Tain, J. L.; Jordan, M. D.; Agramunt, J.; Rubio, B.; Estevez, E.; Molina, F.; Montaner, A.; Guadilla, V.; Fallot, M.; Podolyak, Zs.; Regan, P. H.; Gelletly, W.; Bowry, M.; Mason, P.; Farrelly, G. F.; Rissanen, J.; Eronen, T.; Moore, I.; Penttila, H.; Aysto, J.; Eloma, V.; Hakala, J.; Jokinen, A.; Kolkinen, V.; Reponen, M.; Sonnenschein, V.; Cano-Ott, D.; Martinez, T.; Mendoza, E.; Garcia, A. R.; Gomez-Hornillos, M. B.; Gorlychev, V.; Caballero-Folch, R.; Kondev, F. G.; Sonzogni, A. A.

    2014-06-01

    We present an overview of our activities related to the study of the beta decay of neutron rich nuclei relevant for nuclear applications. Recent results of the study of the beta decay of Br using a new segmented total absorption spectrometer are presented. Our measurements were performed at the IGISOL facility using trap-assisted total absorption spectroscopy.

  2. Total Absorption Study of Beta Decays Relevant for Nuclear Applications and Nuclear Structure

    NASA Astrophysics Data System (ADS)

    Algora, A.; Valencia, E.; Taín, J. L.; Jordan, M. D.; Agramunt, J.; Rubio, B.; Estevez, E.; Molina, F.; Montaner, A.; Guadilla, V.; Fallot, M.; Porta, A.; Zakari-Issoufou, A.-A.; Bui, V. M.; Rice, S.; Podolyák, Zs.; Regan, P. H.; Gelletly, W.; Bowry, M.; Mason, P.; Farrelly, G. F.; Rissanen, J.; Eronen, T.; Moore, I.; Penttilä, H.; Äystö, J.; Eloma, V.; Hakala, J.; Jokinen, A.; Kolkinen, V.; Reponen, M.; Sonnenschein, V.; Cano-Ott, D.; Martínez, T.; Mendoza, E.; Garcia, A. R.; Gomez-Hornillos, M. B.; Gorlychev, V.; Caballero-Folch, R.; Kondev, F. G.; Sonzogni, A. A.

    2014-06-01

    An overview is given of our activities related to the study of the beta decay of neutron rich nuclei relevant for nuclear applications. Recent results of the study of the beta decay of 87,88Br using a new segmented total absorption spectrometer are presented. The measurements were performed at the IGISOL facility using trap-assisted total absorption spectroscopy.

  3. Calorimetry study of microwave absorption of some solid materials.

    PubMed

    He, Chun Lin; Ma, Shao Jian; Su, Xiu Juan; Chen, Yan Qing; Liang, Yu Shi

    2013-01-01

    In practice, the dielectric constant of a material varies the applied frequency the material composition, particle size, purity, temperature, physical state (solid or liquid), and moisture content. All of these parameters might change during processing, therefore, it is difficult to predict how well a material will absorb microwave energy in a given process. When the temperature is measured by a digital thermometer, it could not accurately reflect the true temperature of the bulk materials, especially for mixed materials. Thus, in this paper we measured the microwave absorption characteristics of different materials by calorimetry. The microwave power levels, irradiation times, and masses of the materials were varied. It was difficult to predict the microwave energy absorption characteristics of reagent-grade inorganic compounds based on their color, metallic cation, or water stoichiometry. CuO, MnO2, Fe3O4, and MnSO4 x H2O (Taishan) strongly absorbed microwave energy. Most of the remaining inorganic compounds were poor absorbers, with silica hardly absorbing any microwave energy. Carbon-based materials had significantly different microwave absorption characteristics. Activated carbon and coke were especially sensitive to microwaves, but different types of coal were poor absorbers. The jamesonite concentrate absorbed microwave energy strongly, while the zinc concentrate was a poor absorber. PMID:24779227

  4. Calorimetry study of microwave absorption of some solid materials.

    PubMed

    He, Chun Lin; Ma, Shao Jian; Su, Xiu Juan; Chen, Yan Qing; Liang, Yu Shi

    2013-01-01

    In practice, the dielectric constant of a material varies the applied frequency the material composition, particle size, purity, temperature, physical state (solid or liquid), and moisture content. All of these parameters might change during processing, therefore, it is difficult to predict how well a material will absorb microwave energy in a given process. When the temperature is measured by a digital thermometer, it could not accurately reflect the true temperature of the bulk materials, especially for mixed materials. Thus, in this paper we measured the microwave absorption characteristics of different materials by calorimetry. The microwave power levels, irradiation times, and masses of the materials were varied. It was difficult to predict the microwave energy absorption characteristics of reagent-grade inorganic compounds based on their color, metallic cation, or water stoichiometry. CuO, MnO2, Fe3O4, and MnSO4 x H2O (Taishan) strongly absorbed microwave energy. Most of the remaining inorganic compounds were poor absorbers, with silica hardly absorbing any microwave energy. Carbon-based materials had significantly different microwave absorption characteristics. Activated carbon and coke were especially sensitive to microwaves, but different types of coal were poor absorbers. The jamesonite concentrate absorbed microwave energy strongly, while the zinc concentrate was a poor absorber.

  5. Investigation of SO3 absorption line for in situ gas detection inside combustion plants using a 4-μm-band laser source.

    PubMed

    Tokura, A; Tadanaga, O; Nishimiya, T; Muta, K; Kamiyama, N; Yonemura, M; Fujii, S; Tsumura, Y; Abe, M; Takenouchi, H; Kenmotsu, K; Sakai, Y

    2016-09-01

    We have investigated 4-μm-band SO3 absorption lines for in situSO3 detection using a mid-infrared laser source based on difference frequency generation in a quasi-phase-matched LiNbO3 waveguide. In the wavelength range of 4.09400-4.10600 μm, there were strong SO3 absorption lines. The maximum absorption coefficient at a concentration of 170 ppmv was estimated to be about 3.2×10-5  cm-1 at a gas temperature of 190°C. In coexistence with H2O, the reduction of the SO3 absorption peak height was observed, which was caused by sulfuric acid formation. We discuss a method of using an SO3 equilibrium curve to derive the total SO3 molecule concentration. PMID:27607263

  6. Spectroscopy of Bright Quasars with the Hubble Space Telescope and Lyman-Alpha Absorption Lines in the Redshift Range 0.5 < Z < 1.7

    NASA Astrophysics Data System (ADS)

    Impey, C. D.; Petry, C. E.; Malkan, M. A.; Webb, W.

    1996-06-01

    We report ultraviolet spectroscopy of three bright quasars obtained with the Faint Object Spectrograph of the Hubble Space Telescope. The good quality spectra covering the range 1800-3300 A result from spectropolarimetry acquired for these targets, the interpretation of which has been published elsewhere. Objective algorithms were used to select absorption lines whose strength exceeded 4 times the rms noise in the nearby continuum, resulting in 109 significant lines for PG 1222+228, 91 significant lines for PG 1634+706, and 19 significant lines for PG 2302+029. Most of the spectral range covers the region with a high density of lines due to intervening absorbers, blueward of the Lyman- α emission line. In PG 1222+228, we identify about 35% of the lines as being associated with the seven metal line systems already known in this quasar. Three have seven or more metal lines identified. An additional 12% are either galactic lines or Lyman-α, Lyman-β pairs with no associated metals. In PG 1634 + 706, nearly 42% of the absorption lines are identified with metal systems. Some are associated with the two metal line systems previously known in this quasar, others are associated with two newly identified C IV Systems at z = 0.6540 and z = 0.9057. Another 19% are galactic lines or Lyman-α, Lyman-β pairs with no associated metals. Six galactic lines are identified in the spectrum of PG 2302 + 029; no lines due to intervening absorbers could be identified. The data for PG 1222 + 228 and PG 1634 + 706 can be used to estimate the number density of Lyman-α absorbers in the redshift range 0.5 < z < 1.7. Above an effective rest equivalent width of 0.4 A there are 25 Lyman-α lines in PG 1222 + 228 in the wavelength range 2300- 3300 A, and 11 Lyman-α lines in PG 1634 + 706 in the wavelength range 1865-2650 A. We have been able to demonstrate that the identification procedure and the method of fitting lines in blended regions is unlikely to contribute systematic errors beyond

  7. INFRARED ABSORPTION LINES TOWARD NGC 7538 IRS 1: ABUNDANCES OF H{sub 2}, H{sub 3}{sup +}, AND CO

    SciTech Connect

    Goto, Miwa; Geballe, T. R.; Usuda, Tomonori E-mail: tgeballe@gemini.edu

    2015-06-10

    We report high-resolution near-infrared absorption spectroscopy of H{sub 2}, H{sub 3}{sup +}, and CO toward the young high mass object NGC 7538 IRS 1. The v = 1–0 H{sub 2} S(0) line and lines in the CO v = 2–0 band were detected; the v = 1–0 H{sub 2} S(1) line and the v = 1–0 H{sub 3}{sup +} lines [R(1, 1){sup l}, R(1, 0), R(1, 1){sup u}] were not detected. The line of sight traverses two clouds, with temperatures 45 and 259 K and with roughly equal column densities of CO. Assuming that H{sub 2} is at the same temperature as CO and that the two species are uniformly mixed, [H{sub 2}]/[CO] = 3600 ± 1200. NGC 7538 is the most distant object from the Galactic center for which [H{sub 2}]/[CO] has been directly measured using infrared absorption spectroscopy.

  8. The Hubble Space Telescope quasar absorption line key project. I - First observational results, including Lyman-alpha and Lyman-limit systems

    NASA Technical Reports Server (NTRS)

    Bahcall, John N.; Bergeron, Jacqueline; Boksenberg, Alec; Hartig, George F.; Jannuzi, Buell T.; Kirhakos, Sofia; Sargent, W. L. W.; Savage, Blair D.; Schneider, Donald P.; Turnshek, David A.

    1993-01-01

    Spectra are presented for 37 quasars with small and moderate redshifts; the quasars were observed with the Faint Object Spectrograph of the HST. New higher resolution measurements of the absorption lines in the UV spectra of 11 quasars with emission-line redshifts that lie between 0.3 and 1.0 are reported. Calibrated spectra and continuum fits are shown for each object. A total of 104 extragalactic Ly-alpha systems are identified, nine of which are found at the same redshifts as metal-line systems. The local number density of Ly-alpha systems with rest equivalent widths larger than 0.32 A and without detected metal lines is about 15.1 +/- 4.3 Ly-alpha systems per unit redshift with gamma = 0.30 +/- 0.62 and W* = 0.22 +/- 0.02 A. A total of 10 Lyman-limit systems with an optical depth greater than 0.4 are identified. The paucity of damped Ly-alpha lines at small and moderate redshifts shows that the number density of damped absorption systems decreases with decreasing redshift.

  9. Iron absorption in raw and cooked bananas: A field study using stable isotopes in women

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Banana is a staple food in many regions with high iron deficiency and may be a potential vehicle for iron fortification. However, iron absorption from bananas is not known. The objective of this study was to evaluate total iron absorption from raw and cooked bananas. Thirty women (34.9 +/- 6.6 years...

  10. Case study for a high temperature ultraviolet absorption hygrometer

    SciTech Connect

    Gersh, M.E.; Bangert, M. ); Matthew, M.W. ); Lowe, R. )

    1989-10-01

    The motivation for this program is the observation that the use of reliable and accurate hygrometers to monitor or control the processes in industrial drying chambers could result in a significant reduction in the energy usage of the United States. At the present time, there are no commercially available hygrometers which have the required characteristics of a measurement capability at simultaneously high temperature and humidity, along with the ability to operate for long periods in a severely contaminating and/or particle-laden environment. The goal of this program was the development of an industrial hygrometer which can be employed to monitor the humidity during industrial drying operations. This requires a device which can operate at temperatures up to 500{degree}C, at high humidity (50--100%), and in environments containing particulates and/or fouling or corrosive vapors. The approach taken by Spectral Sciences, Inc. (SSI) for the development of a practical hygrometer for these operational conditions is the use of the differential absorption of light by water vapor. Light absorbed at two ultraviolet (UV) wavelengths determines the absolute humidity (measurement of temperature by conventional means also permits the determination of relative humidity). Due to the use of this principle to measure the humidity, we have termed this instrument an Ultraviolet Absorption Hygrometer (UVAH). 11 figs.

  11. Preliminary studies of absorption and excretion of benoxaprofen in man.

    PubMed Central

    Smith, G L; Goulbourn, R A; Burt, R A; Chatfield, D H

    1977-01-01

    1 Benoxaprofen is a new acidic anti-inflammatory compound which was well absorbed after oral administration to man. 2 Single doses of 100, 200 and 400 mg produced mean peak concentrations in the plasma of 13.0, 33.5 and 45.3 microgram respectively, and the plasma half-life of the compound was between 30 and 35 hours. 3 Multiple dosing with 25 and 50 mg every 24 h achieved an equilibrium conentration in the plasma after 6-8 days, while dosing with 100 mg every 12 h enabled equilibrium to be reached in 3-6 days. Plasma concentrations between 35 and 45 microgram/ml were achieved by giving 100 mg doses every 12 hours. 4 Absorption of benoxaprofen was delayed when the drug was given with food, but the total amount absorbed remained the same. 5 The effect of milling the material to small particle size (19 micron) was to increase the rate of absorption compared to that of unmilled material (58 micron). 6 Benoxaprofen was well tolerated by healthy male subject in the doses given. PMID:303115

  12. Evidence for Ultra-fast Outflows in Radio-quiet Active Galactic Nuclei. II. Detailed Photoionization Modeling of Fe K-shell Absorption Lines

    NASA Astrophysics Data System (ADS)

    Tombesi, F.; Cappi, M.; Reeves, J. N.; Palumbo, G. G. C.; Braito, V.; Dadina, M.

    2011-11-01

    X-ray absorption line spectroscopy has recently shown evidence for previously unknown Ultra-fast Outflows (UFOs) in radio-quiet active galactic nuclei (AGNs). These have been detected essentially through blueshifted Fe XXV/XXVI K-shell transitions. In the previous paper of this series we defined UFOs as those highly ionized absorbers with an outflow velocity higher than 10,000 km s-1 and assessed the statistical significance of the associated blueshifted absorption lines in a large sample of 42 local radio-quiet AGNs observed with XMM-Newton. The present paper is an extension of that work. First, we report a detailed curve of growth analysis of the main Fe XXV/XXVI transitions in photoionized plasmas. Then, we estimate an average spectral energy distribution for the sample sources and directly model the Fe K absorbers in the XMM-Newton spectra with the detailed Xstar photoionization code. We confirm that the frequency of sources in the radio-quiet sample showing UFOs is >35% and that the majority of the Fe K absorbers are indeed associated with UFOs. The outflow velocity distribution spans from ~10,000 km s-1 (~0.03c) up to ~100,000 km s-1 (~0.3c), with a peak and mean value of ~42,000 km s-1 (~0.14c). The ionization parameter is very high and in the range log ξ ~ 3-6 erg s-1 cm, with a mean value of log ξ ~ 4.2 erg s-1 cm. The associated column densities are also large, in the range N H ~ 1022-1024 cm-2, with a mean value of N H ~ 1023 cm-2. We discuss and estimate how selection effects, such as those related to the limited instrumental sensitivity at energies above 7 keV, may hamper the detection of even higher velocities and higher ionization absorbers. We argue that, overall, these results point to the presence of extremely ionized and possibly almost Compton-thick outflowing material in the innermost regions of AGNs. This also suggests that UFOs may potentially play a significant role in the expected cosmological feedback from AGNs and their study can

  13. EVIDENCE FOR ULTRA-FAST OUTFLOWS IN RADIO-QUIET ACTIVE GALACTIC NUCLEI. II. DETAILED PHOTOIONIZATION MODELING OF Fe K-SHELL ABSORPTION LINES

    SciTech Connect

    Tombesi, F.; Reeves, J. N.; Palumbo, G. G. C.; Braito, V.

    2011-11-20

    X-ray absorption line spectroscopy has recently shown evidence for previously unknown Ultra-fast Outflows (UFOs) in radio-quiet active galactic nuclei (AGNs). These have been detected essentially through blueshifted Fe XXV/XXVI K-shell transitions. In the previous paper of this series we defined UFOs as those highly ionized absorbers with an outflow velocity higher than 10,000 km s{sup -1} and assessed the statistical significance of the associated blueshifted absorption lines in a large sample of 42 local radio-quiet AGNs observed with XMM-Newton. The present paper is an extension of that work. First, we report a detailed curve of growth analysis of the main Fe XXV/XXVI transitions in photoionized plasmas. Then, we estimate an average spectral energy distribution for the sample sources and directly model the Fe K absorbers in the XMM-Newton spectra with the detailed Xstar photoionization code. We confirm that the frequency of sources in the radio-quiet sample showing UFOs is >35% and that the majority of the Fe K absorbers are indeed associated with UFOs. The outflow velocity distribution spans from {approx}10,000 km s{sup -1} ({approx}0.03c) up to {approx}100,000 km s{sup -1} ({approx}0.3c), with a peak and mean value of {approx}42,000 km s{sup -1} ({approx}0.14c). The ionization parameter is very high and in the range log {xi} {approx} 3-6 erg s{sup -1} cm, with a mean value of log {xi} {approx} 4.2 erg s{sup -1} cm. The associated column densities are also large, in the range N{sub H} {approx} 10{sup 22}-10{sup 24} cm{sup -2}, with a mean value of N{sub H} {approx} 10{sup 23} cm{sup -2}. We discuss and estimate how selection effects, such as those related to the limited instrumental sensitivity at energies above 7 keV, may hamper the detection of even higher velocities and higher ionization absorbers. We argue that, overall, these results point to the presence of extremely ionized and possibly almost Compton-thick outflowing material in the innermost regions of

  14. Evidence for Ultra-Fast Outflows in Radio-Quiet AGNs. 2; Detailed Photoionization Modeling of Fe K-Shell Absorption Lines

    NASA Technical Reports Server (NTRS)

    Tombesi, Francesco; Clapp, M.; Reeves, J. N.; Palumbo, G. G. C.; Braito, V.; Dadina, M.

    2011-01-01

    X-ray absorption line spectroscopy has recently shown evidence for previously unknown Ultra-fast Outflows (UFOs) in radio-quiet AGNs. In the previous paper of this series we defined UFOs as those absorbers with an outflow velocity higher than 10,000km/s and assessed the statistical significance of the associated blue shifted FeK absorption lines in a large sample of 42 local radio-quiet AGNs observed with XMM-Newton. In the present paper we report a detailed curve of growth analysis and directly model the FeK absorbers with the Xstar photo-ionization code. We confirm that the frequency of sources in the radio-quiet sample showing UFOs is >35%. The outflow velocity distribution spans from \\sim10,000km/s (\\sim0.03c) up to \\siml00,000kmis (\\sim0.3c), with a peak and mean value of\\sim42,000km/s (\\sim0.14c). The ionization parameter is very high and in the range log\\xi 3-6 erg s/cm, with a mean value of log\\xi 4.2 erg s/cm. The associated column densities are also large, in the range N_H\\siml0(exp 22)-10(exp 24)/sq cm, with a mean value of N_H\\siml0(exp23)/sq cm. We discuss and estimate how selection effects, such as those related to the limited instrumental sensitivity at energies above 7keV, may hamper the detection of even higher velocities and higher ionization absorbers. We argue that, overall, these results point to the presence of extremely ionized and possibly almost Compton thick outflowing material in the innermost regions of AGNs. This also suggests that UFOs may potentially play a significant role in the expected cosmological feedback from AGNs and their study can provide important clues on the connection between accretion disks, winds and jets.

  15. Automated on-line preconcentration of trace aqueous mercury with gold trap focusing for cold vapor atomic absorption spectrometry.

    PubMed

    Puanngam, Mahitti; Dasgupta, Purnendu K; Unob, Fuangfa

    2012-09-15

    A fully automated system for the determination of trace mercury in water by cold vapor atomic absorption spectrometry (CVAAS) is reported. The system uses preconcentration on a novel sorbent followed by liberation of the mercury and focusing by a gold trap. Mercury ions were extracted from water samples by passage through a solid phase sorbent column containing 2-(3-(2-aminoethylthio)propylthio)ethanamine modified silica gel. The captured mercury is released by thiourea and then elemental Hg is liberated by sodium borohydride. The vapor phase Hg is recaptured on a gold-plated tungsten filament. This is liberated as a sharp pulse (half-width<2 s) by directly electrically heating the tungsten filament in a dry argon stream. The mercury is measured by CVAAS; no moisture removal is needed. The effects of chloride and selected interfering ions were studied. The sample loading flow rate and argon flow rates for solution purging and filament sweeping were optimized. An overall 50-fold improvement in the limit of detection was observed relative to direct measurement by CVAAS. With a relatively modest multi-user instrument we attained a limit of detection of 35 ng L(-1) with 12% RSD at 0.20 μg L(-1) Hg level. The method was successfully applied to accurately determine sub-μg L(-1) level Hg in standard reference water samples.

  16. Gamma resonance absorption. New approach in human body composition studies.

    PubMed

    Wielopolski, L; Vartsky, D; Pierson, R; Goldberg, M; Heymsfield, S; Yasumura, S; Melnychuk, S T; Sredniawski, J

    2000-05-01

    The main stream of body elemental analysis is based on the delayed, prompt, and inelastic neutron interactions with the main elements found in the human body, and subsequent analysis of the measured delayed or prompt gamma ray spectra. This methodology traditionally was, and still is, applied for whole body analysis and requires relatively high radiation doses. A new method, based on gamma nuclear resonance absorption (GNRA), is being established at Brookhaven National Laboratory as part of its body composition program. The method is element specific with a high tomographic spatial-resolution capability, at a small fraction of the radiation dose used in the current system. The new system, with its components and capabilities, is described below. PMID:10865747

  17. Absorption and fluorescent spectral studies of imidazophenazine derivatives.

    PubMed

    Ryazanova, O A; Zozulya, V N; Voloshin, I M; Karachevtsev, V A; Makitruk, V L; Stepanian, S G

    2004-07-01

    Absorption and fluorescent spectra as well as fluorescence polarization degree of imidazo-[4,5-d]-phenazine (F1) and its two modified derivatives, 2-trifluoridemethylimidazo-[4,5-d]-phenazine (F2) and 1,2,3-triazole-[4,5-d]-phenazine (F3), were investigated in organic solvents of various polarities and hydrogen bonding abilities. Extinction coefficients of F2 and F3 are increased, their fluorescence Stokes shifts are reduced in comparison with those for unmodified imidazophenazine. For F3 a red shift of the longwave absorption band is observed by 15-20 nm. Modifications of imidazophenazine have led to a sufficient increase of fluorescence polarization degrees that enables to use F2 and F3 as promising fluorescent probes with polarization method application. The configuration, atomic charge distribution and dipole moments of the isolated dye molecules in the ground state were calculated by the DFT method. The computation has revealed that ground state dipole moments of F1, F2, and F3 differ slightly and are equal to 3.5, 3.2, and 3.7D, respectively. The changes in dipole moments upon the optical excitation for all derivatives estimated using Lippert equation were found to be Deltamu = 9 D. The energies of the electronic S1<--S0 transition in solvents of different proton donor abilities were determined, and energetic diagram illustrating the substituent effect was plotted. For nucleoside analogs of these compounds, covalently incorporated into a nucleotide chain, we have considered a possibility to use them as fluorescent reporters of hybridization of antisense oligonucleotides, as well as molecular anchors for its stabilization. PMID:15248979

  18. Spectral aspects of the determination of Si in organic and aqueous solutions using high-resolution continuum source or line source flame atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Kowalewska, Zofia; Pilarczyk, Janusz; Gościniak, Łukasz

    2016-06-01

    High-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) was applied to reveal and investigate spectral interference in the determination of Si. An intensive structured background was observed in the analysis of both aqueous and xylene solutions containing S compounds. This background was attributed to absorption by the CS molecule formed in the N2O-C2H2 flame. The lines of the CS spectrum at least partially overlap all five of the most sensitive Si lines investigated. The 251.611 nm Si line was demonstrated to be the most advantageous. The intensity of the structured background caused by the CS molecule significantly depends on the chemical form of S in the solution and is the highest for the most-volatile CS2. The presence of O atoms in an initial S molecule can diminish the formation of CS. To overcome this S effect, various modes of baseline fitting and background correction were evaluated, including iterative background correction (IBC) and utilization of correction pixels (WRC). These modes were used either independently or in conjunction with least squares background correction (LSBC). The IBC + LSBC mode can correct the extremely strong interference caused by CS2 at an S concentration of 5% w:w in the investigated solution. However, the efficiency of this mode depends on the similarity of the processed spectra and the correction spectra in terms of intensity and in additional effects, such as a sloping baseline. In the vicinity of the Si line, three lines of V were recorded. These lines are well-separated in the HR-CS FAAS spectrum, but they could be a potential source of overcorrection when using line source flame atomic absorption spectrometry (LS FAAS). The expected signal for the 251.625 nm Fe line was not registered at 200 mg L- 1 Fe concentration in the solution, probably due to the diminished population of Fe atoms in the high-temperature flame used. The observations made using HR-CS FAAS helped to establish a "safe" level

  19. Absorption Line Survey of H3+ toward the Galactic Center Sources. II. Eight Infrared Sources within 30 pc of the Galactic Center

    NASA Astrophysics Data System (ADS)

    Goto, Miwa; Usuda, Tomonori; Nagata, Tetsuya; Geballe, T. R.; McCall, Benjamin J.; Indriolo, Nick; Suto, Hiroshi; Henning, Thomas; Morong, Christopher P.; Oka, Takeshi

    2008-11-01

    Infrared absorption lines of H+3, including the metastable R(3,3)l line, have been observed toward eight bright infrared sources associated with hot and massive stars located in and between the Galactic center cluster and the Quintuplet cluster 30 pc to the east. The absorption lines with high-velocity dispersion arise in the Galaxy's central molecular zone (CMZ) as well as in foreground spiral arms. The temperature and density of the gas in the CMZ, as determined from the relative strengths of the H3+ lines, are T = 200-300 K and n <= 50-200 cm-3. The detection of high column densities of H3+ toward all eight stars implies that this warm and diffuse gaseous environment is widespread in the CMZ. The products of the ionization rate and path length for these sight lines are 1000 and 10 times higher than in dense and diffuse clouds in the Galactic disk, respectively, indicating that the ionization rate, ζ, is not less than 10-15 s-1 and that L is at least on the order of 50 pc. The warm and diffuse gas is an important component of the CMZ, in addition to the three previously known gaseous environments: (1) cold molecular clouds observed by radio emission of CO and other molecules; (2) hot (T = 104-106 K) and highly ionized diffuse gas (ne = 10-100 cm-3) seen in radio recombination lines, far infrared atomic lines, and radio-wave scattering; and (3) ultrahot (T = 107-108 K) X-ray emitting plasma. Its prevalence significantly changes the understanding of the environment of the CMZ. The sight line toward GC IRS 3 is unique in showing an additional H3+ absorption component, which is interpreted as being due to either a cloud associated with circumnuclear disk or the "50 km s-1 cloud" known from radio observations. An infrared pumping scheme is examined as a mechanism to populate the (3,3) metastable level in this cloud. Based on data collected at Subaru Telescope, operated by the National Astronomical Observatory of Japan.

  20. Theoretical investigation of the broad one-photon absorption line-shape of a flexible symmetric carbazole derivative.

    PubMed

    Liu, Yanli; Cerezo, Javier; Santoro, Fabrizio; Rizzo, Antonio; Lin, Na; Zhao, Xian

    2016-08-17

    The one-photon absorption spectrum of a carbazole derivative has been studied by employing density functional response theory combined with a mixed quantum/classical (QC) approach to simulate the spectral shape. In a first step of our analysis we employed the vertical gradient (VG) vibronic model to investigate the role of Franck-Condon (FC) profiles of the first ten electronic excited states of the system, underlying most of the range of the experimental spectrum. We then focussed on the first six excited states covering the low-energy region of the spectrum, and investigated the effect of inter-state electronic couplings on the spectral shapes within Herzberg-Teller (HT) theory. Furthermore, in order to introduce the broadening effects due to the two inter-ring torsions, we employed a QC approach, adopting VG vibronic models for high-frequency modes and computing the contribution of the torsions to the spectrum from the distribution of the excitation energies along a two-dimensional relaxed potential energy. Finally, we estimated the solvent inhomogeneous broadening by computing the solvent reorganization energy using a polarizable continuum model. Our calculations allow us to obtain a non-phenomenological description of the low-energy part of the spectrum in semi-quantitative agreement with experiment and to dissect the relative importance of solvent, torsional flexibility, FC vibronic progressions, and inter-state couplings in determining its broad spectral shapes and the modulation of its intensity. Our analysis also clearly highlights that the investigated carbazole represents a big challenge for available methodologies due to the existence of many close-lying excited electronic states coupled by internal low-frequency and high-frequency motions and by solvent fluctuations. The study of their impact on the spectra at the HT level is only approximate and more refined treatments would require a fully quantum-dynamical calculation on the manifold of the coupled

  1. Intestinal perfusion studies in tropical sprue. 1. Amino acid and dipeptide absorption.

    PubMed Central

    Hellier, M D; Radhakrishnan, A N; Ganapathy, V; Mathan, V I; Baker, S J

    1976-01-01

    Intestinal absorption of glycine 20 mmol/1, glycyl-glycine 10 mmol/1 plus L-leucine 10 mmol/1, and glycyl-L-leucine 10 mmol/1 has been studied by intestinal perfusion in 11 patients with tropical sprue and 10 control subjects. The patients with sprue had a significant reduction in the rate of absorption of glycine from a 20 mmol/1 solution, but there were no significant differences in the absorption of the other substances. The failure to demonstrate any difference in the absorption of these substances is probably related to their low concentration relative to the maximum absorptive capacity of the intestine. In both groups of subjects the kinetic advantage of glycyl-glycine absorption as compared with glycine absorption was maintained. When the dipeptides were perfused, free amino acids appeared in the perfusate presumably by "back diffusion" from the mucosal cells. In the case of glycyl-L-leucine considerably more glycine and leucine were found in the perfusate in patients with sprue than in the control subjects. There was no correlation between peptide absorption and the concentration of total glycly-glycine hydrolase and glycyl-L-leucine hydrolase, measured as combined brush border and cytosol enzymes. The concentrations of these enzymes were similar in both groups of subjects. PMID:964683

  2. Discovery of a cyclotron absorption line in the spectrum of the binary X-ray pulsar 4U 1538 - 52 observed by Ginga

    NASA Technical Reports Server (NTRS)

    Clark, George W.; Woo, Jonathan W.; Nagase, Fumiaki; Makishima, Kazuo; Sakao, Taro

    1990-01-01

    A cyclotron absorption line near 20 keV has been found in the spectrum of the massive eclipsing binary X-ray pulsar 4U 1538 - 52 in observations with the Ginga observatory. The line is detected throughout the 529 s pulse cycle with a variable equivalent width that has its maximum value during the smaller peak of the two-peak pulse profile. It is found that the profile of the pulse and the phase-dependence of the cyclotron line can be explained qualitatively by a pulsar model based on recent theoretical results on the properties of pencil beams emitted by accretion-heated slabs of magnetized plasma at the magnetic poles of a neutron star. The indicated field at the surface of the neutron star is 1.7 (1 + z) x 10 to the 12th G, where z is the gravitational redshift.

  3. Terminal velocity of wind, mass loss, and absorption lines of the central star of the planetary nebula 75 + 35.1 deg

    NASA Technical Reports Server (NTRS)

    Feibelman, Walter A.; Bruhweiler, Frederick C.

    1989-01-01

    The high-galactic latitude planetary nebula 75 + 35.1 deg was observed in the high-dispersion mode of the International Ultraviolet Explorer (IUE) satellite in the wavelength range 1150-1950 A. The N V resonance doublet at 1240 A and O V subordinate line at 1371 A exhibit strong stellar P Cygni profiles with absorption extending to -2150 km/s and -1000 km/s, respectively. Application of the first moment method implies a mass-loss rate of M = (1-3) x 10 to the -8th solar mass/yr. The high ionization of the wind lines and the presence of strong Fe VI and Fe V lines in the stellar photosphere support that this object is quite hot. A Teff of 75,000 + or - 10,000 K was adopted, although Tc = 94,000 K was found previously from low-resolution IUE data.

  4. Terminal velocity of wind, mass loss, and absorption lines of the central star of the planetary nebula 75 + 35. 1 deg

    SciTech Connect

    Feibelman, W.A.; Bruhweiler, F.C. Catholic Univ. of America, Washington, DC )

    1989-12-01

    The high-galactic latitude planetary nebula 75 + 35.1 deg was observed in the high-dispersion mode of the International Ultraviolet Explorer (IUE) satellite in the wavelength range 1150-1950 A. The N V resonance doublet at 1240 A and O V subordinate line at 1371 A exhibit strong stellar P Cygni profiles with absorption extending to -2150 km/s and -1000 km/s, respectively. Application of the first moment method implies a mass-loss rate of M = (1-3) x 10 to the -8th solar mass/yr. The high ionization of the wind lines and the presence of strong Fe VI and Fe V lines in the stellar photosphere support that this object is quite hot. A Teff of 75,000 + or - 10,000 K was adopted, although Tc = 94,000 K was found previously from low-resolution IUE data. 18 refs.

  5. Flow injection on-line dilution for zinc determination in human saliva with electrothermal atomic absorption spectrometry detection.

    PubMed

    Burguera-Pascu, Margarita; Rodríguez-Archilla, Alberto; Burguera, José Luis; Burguera, Marcela; Rondón, Carlos; Carrero, Pablo

    2007-09-26

    An automated method is described for the determination of zinc in human saliva by electrothermal atomic absorption spectrometry (ET AAS) after on-line dilution of samples with a significant reduction of sample consumption per analysis (<0.4 mL including the dead volume of the system). In order to fulfill this aim without changing the sample transport conduits during the experiments, a flow injection (FI) dilution system was constructed. Its principal parts are: one propulsion device (peristaltic pump, PP) for either samples, standards or washing solution all located in an autosampler tray and for the surfactant solution (Triton X-100) used as diluent, and a two-position time based solenoid injector (TBSI(1)) which allowed the introduction of 10 microL of either solution in the diluent stream. To avoid unnecessary waste of samples, the TBSI(1) also permitted the recirculation of the solutions to their respective autosampler cups. The downstream diluted solution fills a home made sampling arm assembly. The sequential deposition of 20 microL aliquots of samples or standards on the graphite tube platform was carried out by air displacement with a similar time based solenoid injector (TBSI(2)). The dilution procedure and the injection of solutions into the atomizer are computer controlled and synchronized with the operation of the temperature program. Samples or standards solutions were submitted to two drying steps (at 90 and 130 degrees C), followed by pyrolysis and atomization at 700 and 1700 degrees C, respectively. The aqueous calibration was linear up to 120.0 microgL(-1) for diluted standard solutions/samples and its slope was similar (p>0.05) to the standard addition curve, indicating lack of matrix effect. The precision tested by repeated analysis of real saliva samples was less than 3% and the detection limit (3sigma) was of 0.35 microgL(-1). To test the accuracy of the proposed procedure, recovery tests were performed, obtaining mean recovery of added zinc of

  6. The Dust, Nebular Emission, and Dependence on QSO Radio Properties of the Associated Mg II Absorption Line Systems

    NASA Astrophysics Data System (ADS)

    Khare, Pushpa; Berk Daniel, Vanden; Rahmani, Hadi; York, Donald G.

    2014-10-01

    We studied dust reddening and [O II] emission in 1730 Mg II associated absorption systems (AAS; relative velocity with respect to QSOs, <=3000 km s-1 in units of velocity of light, β, <=0.01) with 0.4 <=z abs <= 2 in the Sloan Digital Sky Survey DR7, focusing on their dependence on the radio and other QSO properties. We used control samples, several with matching radio properties, to show that (1) AAS in radio-detected (RD) QSOs cause 2.6 ± 0.2 times higher dust extinction than those in radio-undetected (RUD) ones, which in turn cause 2.9 ± 0.7 times the dust extinction in the intervening systems; (2) AAS in core-dominated QSOs cause 2.0 ± 0.1 times higher dust extinction than those in lobe-dominated QSOs; (3) the occurrence of AAS is 2.1 ± 0.2 times more likely in RD QSOs than in RUD QSOs and 1.8 ± 0.1 time more likely in QSOs having black holes with masses larger than 1.23 × 109 M ⊙ than in those with lower-mass black holes; and (4) there is excess flux in [O II]λ3727 emission in the composite spectra of the AAS samples compared with those of the control samples, which is at the emission redshift. The presence of AAS enhances the O II emission from the active galactic nucleus and/or the host galaxy. This excess is similar for both RD and RUD samples and is 2.5 ± 0.4 times higher in lobe-dominated samples than in core-dominated samples. The excess depends on the black hole mass and Eddington ratio. All these point to the intrinsic nature of the AAS except for the systems with z abs > z em, which could be infalling galaxies.

  7. H2O and O2 Absorption-Line Abundances in the Coma of Comet 67P/Churyumov-Gerasimenko Measured by the R-Alice Ultraviolet Spectrograph

    NASA Astrophysics Data System (ADS)

    Keeney, Brian A.; Stern, S. Alan; Schindhelm, Eric; A'Hearn, Michael F.; Bertaux, Jean-Loup; Bieler, Andre; Feaga, Lori M.; Feldman, Paul D.; Parker, Joel Wm; Steffl, Andrew Joseph; Weaver, Harold A.

    2016-10-01

    The Alice far-UV spectrograph, aboard the ESA Rosetta spacecraft, has observed emissions in the wavelength range 800-2000 Å from the coma of Comet 67P/Churyumov-Gerasimenko since before orbital insertion in September 2014. We present novel observations of the cometary coma in absorption against the stellar continuum of UV-bright stars that were targeted or serendipitously observed near the comet's nucleus between April 2015 and February 2016 at heliocentric radii ranging from 1.2 to 2.4 AU. These spectra show clear signatures of absorption from gaseous H2O and O2. The observed H2O column densities agree well with values found by Rosetta's VIRTIS instrument (Bockelée-Morvan et al. 2015, A&A, 583, A6) and can be reasonably described by a simple Haser model. However, the absorption-derived O2/H2O ratio is somewhat larger than the 1-10% range reported by Rosetta's ROSINA mass spectrometer (Bieler et al. 2015, Nature, 526, 678) from September 2014 through March 2015 at heliocentric radii of 2.1-3.2 AU. We explore potential causes for this discrepancy, including systematic biases in the absorption-line measurements and seasonal variations in O2/H2O as the comet approaches perihelion.

  8. Estimating Magnetic Fields of Homes Near Transmission Lines in the California Power Line Study

    PubMed Central

    Vergara, Ximena P.; Kavet, Robert; Crespi, Catherine M.; Hooper, Chris; Silva, J. Michael; Kheifets, Leeka

    2015-01-01

    The California Power Line Study is a case-control study investigating the relation between residences near transmission lines and risk of childhood leukemia. It includes 5788 childhood leukemia cases and 5788 matched primary controls born between 1986 and 2007. We describe the methodology for estimating magnetic fields at study residences as well as for characterizing sources of uncertainty in these estimates. Birth residences of study subjects were geocoded and their distances to transmission lines were ascertained. 302 residences were deemed sufficiently close to transmission lines to have non-zero magnetic fields attributable to the lines. These residences were visited and detailed data, describing the physical configuration and dimensions of the lines contributing to the magnetic field at the residence, were collected. Phasing, loading, and directional load flow data for years of birth and diagnosis for each subject as well as for the day of site visit were obtained from utilities when available; when yearly average load for a particular year was not available, extrapolated values based on expert knowledge and prediction models were obtained. These data were used to estimate the magnetic fields at the center, closest and farthest point of each residence. We found good correlation between calculated fields and spot measurements of fields taken on site during visits. Our modeling strategies yielded similar calculated field estimates, and they were in high agreement with utility extrapolations. Phasing was known for over 90% of the lines. Important sources of uncertainty included a lack of information on the precise location of residences located within apartment buildings or other complexes. Our findings suggest that we were able to achieve high specificity in exposure assessment, which is essential for examining the association between distance to or magnetic fields from power lines and childhood leukemia risk. PMID:26005950

  9. Study on NO2 absorption by ascorbic acid and various chemicals*

    PubMed Central

    Li, Wei; Wu, Cheng-zhi; Fang, He-liang; Shi, Yao; Lei, Le-cheng

    2006-01-01

    Study on NO2 absorption aimed at seeking a better NO2 absorption chemical at pH 4.5~7.0 for application to existing wet flue gas desulfurization (FGD). The results from the double-stirred reactor indicated that ascorbic acid has very high absorption rate at this pH range. The rate constant of ascorbic acid reaction with NO2 (0~1000×10−6 mol/mol) is about 3.54×106 mol/(L·s) at pH 5.4~6.5 at 55 °C. PMID:16365924

  10. Studying the Variation of the Fine-Structure Constant Using Emission-Line Multiplets

    NASA Astrophysics Data System (ADS)

    Grupe, Dirk; Pradhan, Anil K.; Frank, Stephan

    2005-08-01

    As an extension of the method by Bahcall and coworkers to investigate the time dependence of the fine-structure constant, we describe an approach based on new observations of forbidden-line multiplets from different ionic species. We obtain optical spectra of fine-structure transitions in [Ne III], [Ne V], [O III], [O I], and [S II] multiplets from a sample of 14 Seyfert 1.5 galaxies in the low-z range 0.035line studies of the time variation of the fine-structure constant. The approach can be further extended and generalized to a ``many-multiplet emission-line method'' analogous in principle to the corresponding method using absorption lines. With that aim, we note that the theoretical limits on emission-line ratios of selected ions are precisely known and provide well-constrained selection criteria. We also discuss several other forbidden and allowed lines that may constitute the basis for a more rigorous study using high-resolution instruments on the next generation of 8 m class telescopes. Based on observations obtained at MDM Observatory, Arizona.

  11. Experimental study of weak intersystem lines and related strong persistent lines of Ne II

    SciTech Connect

    Bridges, J. M.; Wiese, W. L.

    2007-08-15

    We operated a high-current hollow cathode discharge in pure neon at pressures from 93 to 173 Pa and measured the branching fractions of Ne II emission lines originating from several 2p{sup 5} 3p, 3d, and 4f levels, for which lifetime data were available in the literature. This allowed the determination of transition probabilities for all downward transitions, which included a number of weak intersystem lines. We focused our study on these weak lines, using care to assure correct identifications and accurate intensity measurements, in spite of the presence of much stronger other lines in their vicinity. In contrast to an earlier experiment, we achieved close agreement with a recent multiconfiguration Hartree-Fock calculation.

  12. Mars Ozone Absorption Line Shapes from Infrared Heterodyne Spectra Applied to GCM-Predicted Ozone Profiles and to MEX/SPICAM Column Retrievals

    NASA Technical Reports Server (NTRS)

    Fast, Kelly E.; Kostiuk, T.; Annen, J.; Hewagama, T.; Delgado, J.; Livengood, T. A.; Lefevre, F.

    2008-01-01

    We present the application of infrared heterodyne line shapes of ozone on Mars to those produced by radiative transfer modeling of ozone profiles predicted by general circulation models (GCM), and to contemporaneous column abundances measured by Mars Express SPICAM. Ozone is an important tracer of photochemistry Mars' atmosphere, serving as an observable with which to test predictions of photochemistry-coupled GCMs. Infrared heterodyne spectroscopy at 9.5 microns with spectral resolving power >1,000,000 is the only technique that can directly measure fully-resolved line shapes of Martian ozone features from the surface of the Earth. Measurements were made with Goddard Space Flight Center's Heterodyne instrument for Planetary Wind And Composition (HIPWAC) at the NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii on February 21-24 2008 UT at Ls=35deg on or near the MEX orbital path. The HIPWAC observations were used to test GCM predictions. For example, a GCM-generated ozone profile for 60degN 112degW was scaled so that a radiative transfer calculation of its absorption line shape matched an observed HIPWAC absorption feature at the same areographic position, local time, and season. The RMS deviation of the model from the data was slightly smaller for the GCM-generated profile than for a line shape produced by a constant-with-height profile, even though the total column abundances were the same, showing potential for testing and constraining GCM ozone-profiles. The resulting ozone column abundance from matching the model to the HIPWAC line shape was 60% higher than that observed by SPICAM at the same areographic position one day earlier and 2.5 hours earlier in local time. This could be due to day-to-day, diurnal, or north polar region variability, or to measurement sensitivity to the ozone column and its distribution, and these possibilities will be explored. This work was supported by NASA's Planetary Astronomy Program.

  13. Spectroscopy of α,ω-dithienyl polyenes: evidence for two-photon absorption states from fluorescence studies

    NASA Astrophysics Data System (ADS)

    Natarajan, Lalgudi V.; Kirkpatrick, Sean M.; Sutherland, Richard L.; Sowards, Laura A.; Spangler, Charles W.; Fleitz, Paul A.; Cooper, Thomas M.

    1998-10-01

    The photophysics of a series (alpha) ,(omega) -dithienyl polyenes was studied. Both one photon excited fluorescence and fluorescence originating from two photon absorption states were investigated. There is strong evidence of two photon absorption from fluorescence studies in agreement with our earlier studies involving nonlinear absorption.

  14. [Study on intestinal absorption features of oligosaccharides in Morinda officinalis How. with sigle-pass perfusion].

    PubMed

    Deng, Shao-Dong; Zhang, Peng; Lin, Li; Xiao, Feng-Xia; Lin, Jing-Ran

    2015-01-01

    To study the in situ intestinal absorption of five oligosaccharides contained in Morinda officinalis How. (sucrose, kestose, nystose, 1F-Fructofuranosyinystose and Bajijiasu). The absorption of the five oligosaccharides in small intestine (duodenum, jejunum and ileum) and colon of rats and their contents were investigated by using in situ single-pass perfusion model and HPLC-ELSD. The effects of drug concentration, pH in perfusate and P-glycoprotein inhibitor on the intestinal absorption were investigated to define the intestinal absorption mechanism of the five oligosaccharides in rats. According to the results, all of the five oligosaccharides were absorbed in the whole intestine, and their absorption rates were affected by the pH of the perfusion solution, drug concentration and intestinal segments. Verapamil Hydrochloride could significantly increase the absorptive amount of sucrose and Bajijiasu, suggesting sucrose and Bajijiasu are P-gp's substrate. The five oligosaccharides are absorbed mainly through passive diffusion in the intestinal segments, without saturated absorption. They are absorbed well in all intestines and mainly in duodenum and jejunum.

  15. Microemulsion formulation for enhanced absorption of poorly soluble drugs. II. In vivo study.

    PubMed

    Kawakami, Kohsaku; Yoshikawa, Takayoshi; Hayashi, Takashi; Nishihara, Yoshitaka; Masuda, Kazuyoshi

    2002-05-17

    Oral administration study of microemulsion formulations, which are known to improve the bioavailability of poorly soluble drugs, was performed using rats. Nitrendipine was used as a poorly soluble model drug, and its absorption was enhanced significantly by employing the microemulsion formulations compared to a suspension or an oil solution. The effect of the fed state on the oral absorption of nitrendipine became insignificant with the microemulsion formulations, although it affected the absorption from the suspension formulation significantly. The absorption behavior also varied with the type of surfactant. The absorption from Tween 80-based formulation was very rapid, while HCO-60-based formulation showed prolonged plasma concentration profile. However, the absorption from BL-9EX (polyoxyethylene alkyl ether)-based formulation was hardly observed. Damage to the gastrointestinal mucosa, which seems to be a serious problem of surfactant-based formulations, also differed with the type of surfactant employed. HCO-60 and Tween 80-based formulations were mild to the organs, while BL-9EX-based formulation caused serious damage. The behavior and absorption mechanism of the microemulsion formulations are discussed.

  16. Strong absorption by interstellar hydrogen fluoride: Herschel/HIFI observations of the sight-line to G10.6-0.4 (W31C)

    NASA Astrophysics Data System (ADS)

    Neufeld, D. A.; Sonnentrucker, P.; Phillips, T. G.; Lis, D. C.; de Luca, M.; Goicoechea, J. R.; Black, J. H.; Gerin, M.; Bell, T.; Boulanger, F.; Cernicharo, J.; Coutens, A.; Dartois, E.; Kazmierczak, M.; Encrenaz, P.; Falgarone, E.; Geballe, T. R.; Giesen, T.; Godard, B.; Goldsmith, P. F.; Gry, C.; Gupta, H.; Hennebelle, P.; Herbst, E.; Hily-Blant, P.; Joblin, C.; Kołos, R.; Krełowski, J.; Martín-Pintado, J.; Menten, K. M.; Monje, R.; Mookerjea, B.; Pearson, J.; Perault, M.; Persson, C.; Plume, R.; Salez, M.; Schlemmer, S.; Schmidt, M.; Stutzki, J.; Teyssier, D.; Vastel, C.; Yu, S.; Cais, P.; Caux, E.; Liseau, R.; Morris, P.; Planesas, P.

    2010-07-01

    We report the detection of strong absorption by interstellar hydrogen fluoride along the sight-line to the submillimeter continuum source G10.6-0.4 (W31C). We have used Herschel's HIFI instrument, in dual beam switch mode, to observe the 1232.4763 GHz J = 1-0 HF transition in the upper sideband of the Band 5a receiver. The resultant spectrum shows weak HF emission from G10.6-0.4 at LSR velocities in the range -10 to -3 km s-1, accompanied by strong absorption by foreground material at LSR velocities in the range 15 to 50 km s-1. The spectrum is similar to that of the 1113.3430 GHz 111-000 transition of para-water, although at some frequencies the HF (hydrogen fluoride) optical depth clearly exceeds that of para-H2O. The optically-thick HF absorption that we have observed places a conservative lower limit of 1.6×1014 cm-2 on the HF column density along the sight-line to G10.6-0.4. Our lower limit on the HF abundance, 6×10-9 relative to hydrogen nuclei, implies that hydrogen fluoride accounts for between ~30% and 100% of the fluorine nuclei in the gas phase along this sight-line. This observation corroborates theoretical predictions that - because the unique thermochemistry of fluorine permits the exothermic reaction of F atoms with molecular hydrogen - HF will be the dominant reservoir of interstellar fluorine under a wide range of conditions. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  17. Amplified spontaneous emission measurement of a line-narrowed, tunable, Ti:Al2O3 amplifier using rubidium absorption

    NASA Technical Reports Server (NTRS)

    Barnes, James C.; Barnes, Norman P.; Lockard, George E.; Cross, Patricia L.

    1989-01-01

    Amplified spontaneous emission, ASE, generated by a Ti:Al2O3 laser amplifier has been measured as a function of pump energy, and thus gain, using the atomic absorption of rubidium, Rb, gas at 0.780 micron. By tuning the Ti:Al2O3 laser, the Rb cell could selectively absorb the narrow spectral bandwidth laser radiation while transmitting the wide spectral bandwidth ASE. Transmission of laser amplifier pulses through a Rb absorption cell, measured at various temperatures, thus allows the measurement of the weak ASE in the vicinity of the strong laser pulse. A model for the transmission of Rb as a function of temperature and wavelength has been developed. The measured transmissions are in good agreement with the transmission model predictions.

  18. The dust, nebular emission, and dependence on QSO radio properties of the associated Mg II absorption line systems

    SciTech Connect

    Khare, Pushpa; Daniel, Vanden Berk; Rahmani, Hadi; York, Donald G.

    2014-10-10

    We studied dust reddening and [O II] emission in 1730 Mg II associated absorption systems (AAS; relative velocity with respect to QSOs, ≤3000 km s{sup –1}; in units of velocity of light, β, ≤0.01) with 0.4 ≤z {sub abs} ≤ 2 in the Sloan Digital Sky Survey DR7, focusing on their dependence on the radio and other QSO properties. We used control samples, several with matching radio properties, to show that (1) AAS in radio-detected (RD) QSOs cause 2.6 ± 0.2 times higher dust extinction than those in radio-undetected (RUD) ones, which in turn cause 2.9 ± 0.7 times the dust extinction in the intervening systems; (2) AAS in core-dominated QSOs cause 2.0 ± 0.1 times higher dust extinction than those in lobe-dominated QSOs; (3) the occurrence of AAS is 2.1 ± 0.2 times more likely in RD QSOs than in RUD QSOs and 1.8 ± 0.1 time more likely in QSOs having black holes with masses larger than 1.23 × 10{sup 9} M {sub ☉} than in those with lower-mass black holes; and (4) there is excess flux in [O II]λ3727 emission in the composite spectra of the AAS samples compared with those of the control samples, which is at the emission redshift. The presence of AAS enhances the O II emission from the active galactic nucleus and/or the host galaxy. This excess is similar for both RD and RUD samples and is 2.5 ± 0.4 times higher in lobe-dominated samples than in core-dominated samples. The excess depends on the black hole mass and Eddington ratio. All these point to the intrinsic nature of the AAS except for the systems with z {sub abs} > z {sub em}, which could be infalling galaxies.

  19. Investigation of broadening and shift of vapour absorption lines of H{sub 2}{sup 16}O in the frequency range 7184 – 7186 cm{sup -1}

    SciTech Connect

    Nadezhdinskii, A I; Pereslavtseva, A A; Ponurovskii, Ya Ya

    2014-10-31

    We present the results of investigation of water vapour absorption spectra in the 7184 – 7186 cm{sup -1} range that is of particular interest from the viewpoint of possible application of the data obtained for monitoring water vapour in the Earth's stratosphere. The doublet of H{sub 2}{sup 16}O near ν = 7185.596 cm{sup -1} is analysed. The coefficients of broadening and shift of water vapour lines are found in the selected range in mixtures with buffer gases and compared to those obtained by other authors. (laser spectroscopy)

  20. Microwave absorption and EPR studies of a new copper oxyfluoride superconductor synthesised through the ammonium bifluoride route

    NASA Astrophysics Data System (ADS)

    Kadam, R. M.; Wani, B. N.; Sastry, M. D.; Rao, U. R. K.

    1995-02-01

    The recently reported superconductor Sr 2CuO 2F 2.4 is synthesised by a new route of fluorination by NH 4HF 2 and its superconducting phase is investigated by electron paramagnetic resonance, direct microwave absorption and non-resonant response employing magnetic field modulated microwave absorption. These studies have given clear evidence for the occurrence of a superconducting phase below 40 K. From the magnetic field dependence of the changes in microwave absorption, the lower critical field Hc1 (perpendicular to the c-axis) is determined to be 100 G at 10 K. The EPR studies on this oxyfluoride have shown a Cu 2+ signal with 19F super hyperfine structure due to interaction with two equivalent F nuclei. In view of its low intensity it was assigned to a possible ‘defect site’ in the lattice. The line width of the EPR signal increased in the superconducting phase smearing out the 19F shfs below 35 K. This is consistent with what is normally expected in superconductors.

  1. Topical absorption and toxicity studies of jet fuel hydrocarbons in skin

    NASA Astrophysics Data System (ADS)

    Muhammad, Faqir

    Kerosene-based fuels have been used for many decades. Over 2 million military and civilian personnel each year are occupationally exposed to various jet fuel mixtures. Dermatitis is one of the major health concerns associated with these exposures. In the past, separate absorption and toxicity studies have been conducted to find the etiology of such skin disorders. There was a need for integrated absorption and toxicity studies to define the causative constituents of jet fuel responsible for skin irritation. The focus of this thesis was to study the percutaneous absorption and to identify the hydrocarbons (HC) causing irritation in jet fuels so that preventive measures could be taken in the future. The initial study was conducted to understand the possible mechanism for additive interactions on hydrocarbon absorption/disposition in silastic, porcine skin and isolated perfused porcine skin flap (IPPSF) models. The influence of JP-8 (100) additives (MDA, BHT, 8Q405) on the dermal kinetics of 14C-naphthalene and 14C/3H-dodecane as markers of HC absorption was evaluated. This study indicated that individual and combination of additives influenced marker disposition in different membranes. MDA was a significant suppressor while BHT was a significant enhancer of naphthalene absorption in IPPSF. The 8Q405 significantly reduced naphthalene content in dosed silastic and skin indicating a direct interaction between additive and marker HC. Similarly, the individual MDA and BHT significantly retained naphthalene in the stratum corneum of porcine skin, but the combination of both of these additives statistically decreased the marker retention in the stratum corneum suggesting a potential biological interaction. This study concluded that all components of a chemical mixture should be assessed since the effects of single components administered alone or as pairs may be confounded when all are present in the complete mixture. However, this study indicated that the marker HC

  2. 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…

  3. Gravitationally Redshifted Absorption Lines in the Burst Spectra of the Neutron Star in the X-Ray Binary EXO 0748-676

    NASA Technical Reports Server (NTRS)

    Cottoam, J.; Paerels, F.; Mendez, M.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    The most straightforward manner of determining masses and radii of neutron stars is by measuring the gravitational redshift of spectral lines produced in the neutron star photosphere; such a measurement would provide direct constraints on the mass-to-radius ratio of the neutron star, and therefore on the equation of state for neutron star matter. Using data taken with the Reflection Grating Spectrometer on board the XMM-Newton observatory we identify, for the first time, significant absorption lines in the spectra of 28 bursts of the low-mass X-ray binary EXO 0748-676. The most significant features are consistent with the Fe XXVI and XXV n=2-3 and O VIII n=1-2 transitions, with a redshift of z=0.35, identical within small uncertainties for the different transitions. This constitutes the first direct and unambiguous measurement of the gravitational redshift in a neutron star.

  4. A study of energy absorption rate in a quantum dot and metallic nanosphere hybrid system.

    PubMed

    Schindel, Daniel; Singh, Mahi R

    2015-09-01

    We have studied energy absorption rate in a quantum dot-metallic nanosphere system embedded on a dielectric substrate. We applied a control field to induce dipole moments in the quantum dot and the metal nanosphere, and monitored the energy absorption using a probe field. These external fields induce dipole moments in the metal nanosphere and the quantum dot, and these two structures interact with one another via the dipole-dipole interaction. The density matrix method was used to evaluate the absorption, indicating that it can be shifted by moving the metal nanosphere close to the quantum dot. Also, absorption efficiency can either be quenched or enhanced by the addition of a metal nanosphere. This hybrid system can be used to create ultrafast switching and sensing nanodevices.

  5. A study of energy absorption rate in a quantum dot and metallic nanosphere hybrid system

    NASA Astrophysics Data System (ADS)

    Schindel, Daniel; Singh, Mahi R.

    2015-09-01

    We have studied energy absorption rate in a quantum dot-metallic nanosphere system embedded on a dielectric substrate. We applied a control field to induce dipole moments in the quantum dot and the metal nanosphere, and monitored the energy absorption using a probe field. These external fields induce dipole moments in the metal nanosphere and the quantum dot, and these two structures interact with one another via the dipole-dipole interaction. The density matrix method was used to evaluate the absorption, indicating that it can be shifted by moving the metal nanosphere close to the quantum dot. Also, absorption efficiency can either be quenched or enhanced by the addition of a metal nanosphere. This hybrid system can be used to create ultrafast switching and sensing nanodevices.

  6. Using high spectral resolution spectrophotometry to study broad mineral absorption features on Mars

    NASA Technical Reports Server (NTRS)

    Blaney, D. L.; Crisp, D.

    1993-01-01

    Traditionally telescopic measurements of mineralogic absorption features have been made using relatively low to moderate (R=30-300) spectral resolution. Mineralogic absorption features tend to be broad so high resolution spectroscopy (R greater than 10,000) does not provide significant additional compositional information. Low to moderate resolution spectroscopy allows an observer to obtain data over a wide wavelength range (hundreds to thousands of wavenumbers) compared to the several wavenumber intervals that are collected using high resolution spectrometers. However, spectrophotometry at high resolution has major advantages over lower resolution spectroscopy in situations that are applicable to studies of the Martian surface, i.e., at wavelengths where relatively weak surface absorption features and atmospheric gas absorption features both occur.

  7. Filling in of Fraunhofer and gas-absorption lines in sky spectra as caused by rotational Raman scattering.

    PubMed

    Sioris, C E; Evans, W F

    1999-04-20

    A line-by-line radiative-transfer model to quantify the Ring effect as caused by rotational Raman scattering has been developed for the 310-550-nm spectral interval. The solar zenith angle and the resolution are key input parameters, as is the sky spectrum (excluding inelastic atmospheric scattering), which was modeled with MODTRAN 3.5. The filling in is modeled for ground-based viewing geometry and includes surface reflection and single inelastic scattering. It is shown that O2 contributes half of the filling in of N2. A strong inverse relationship with wavelength is noted in the filling in. A comparison with observations shows moderate agreement. The largest filling in occurs in the Ca II K and H lines.

  8. Non-adiabatic, superfast passage to resonance: an alternative to pulsed fourier transform for absorption line shapes

    NASA Astrophysics Data System (ADS)

    Segel, S. L.; Creel, R. B.; Torgeson, D. R.

    1983-12-01

    We describe the theory, practice and experimental results of a continuous wave (CW) resonance technique which we call non-adiabatic superfast passage (NASP). NASP signal to noise per unit time (SNT) is better than pulsed Fourier transform spectrometers (PFTS) and far better than the conventional CW slow passage NMR using field modulation, lock-in amplifiers and signal averaging techniques. It is most useful in situations of long spin-lattice relaxation time and particularly those cases where the line shape is composed of narrow and broad components, as in a typical second-order quadrupolar perturbed magnetic resonance line shape.

  9. Neutral atomic-carbon quasar absorption-line systems at z> 1.5. Sample selection, H i content, reddening, and 2175 Å extinction feature

    NASA Astrophysics Data System (ADS)

    Ledoux, C.; Noterdaeme, P.; Petitjean, P.; Srianand, R.

    2015-08-01

    We present the results of a search for cold gas at high redshift along quasar lines of sight carried out without any a priori assumption on the neutral atomic-hydrogen content of the absorption-line systems. To do this, we systematically looked for neutral-carbon (C i) λλ1560, 1656 transition lines in 41 696 low-resolution quasar spectra (1.5 < zem < 4.46) from the SDSS-II - Data Release 7 - database. C i absorption lines should indeed probe the shielded gas in the neutral interstellar medium of galaxies more efficiently than traditional tracers such as neutral atomic-hydrogen (H i) damped Lyman-α (DLA) and/or Mg ii systems. We built up a sample of 66 C i absorbers with redshifts in the range 1.5 < z < 3.1 and rest-frame equivalent widths 0.1 21 (atoms cm-2) compared to systematic DLA surveys. Whilst the dust content

  10. Low-Energy Study of Gamma-Ray Bursts Having Spectral Line Features

    NASA Technical Reports Server (NTRS)

    Pangia, Michael J.

    2003-01-01

    Gamma-ray bursts (GRBs) are energetic, short-duration emissions of gamma-rays. The Burst and Transient Source Experiment (BATSE) that was onboard NASA s Compton Gamma-Ray Observatory has done much to advance our understanding of GRBs. Perhaps foremost is to establish that GRBs originate from astronomical sources that exist well beyond our galaxy. Another area in which BATSE has been instrumental is to provide high-resolution data that can be used in spectral studies. Before BATSE, there were many reports of GRB spectra containing what appeared to be spectral absorption lines, whereas Briggs, after an extensive computer search of 117 bright BATSE GRBs, reported finding only one case that might be an absorption line and ten cases that might be emission lines. None of the eleven BATSE cases were definitively identified as spectral lines, and Briggs indicated reasons as to why the pre-BATSE reports should not be taken as conclusive. It remains an open question as to what these spectral-like features are, or if they are even real. The purpose of this work is, for the subset of the eleven BATSE GRBs for which low-energy data are available from two BATSE's Spectroscopy Detectors (SDs), to include these data in the spectral analysis. Such a study will provide additional constraints on the model spectral functions to better ascertain the reality of the line features. The spectral analysis program used was RMFIT. Of the six GRBs that met the selection criteria, the analysis was performed on only three of them due to a lack of time.

  11. An Fe XXIV Absorption Line in the Persistent Spectrum of the Dipping Low-Mass X-Ray Binary 1A 1744-361

    NASA Technical Reports Server (NTRS)

    Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip

    2012-01-01

    We report on Chandra X-ray Observatory (Chandra) High Energy Transmission Grating spectra of the dipping low-mass X-ray binary 1A 1744-361 during its 2008 July outburst. We find that its persistent emission is well modeled by a blackbody (kT approx. 1.0 keV) plus power law (Gamma approx. 1.7) with an absorption edge. In the residuals of the combined spectrum, we find a significant absorption line at 6.961 +/- 0.002 keV, consistent with the Fe xxvi (hydrogen-like Fe) 2-1 transition.We place an upper limit on the velocity of a redshifted flow of nu < 221 km/s. We find an equivalent width for the line of 27+2/-3 eV, from which we determine a column density of (7 +/- 1)×10(exp 17) /sq. cm via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of >103.6 erg cm/s. We discuss what implications the feature has on the system and its geometry. We also present Rossi X-ray Timing Explorer data accumulated during this latest outburst and, via an updated color-color diagram, clearly show that 1A 1744-361 is an "atoll" source

  12. AN Fe XXIV ABSORPTION LINE IN THE PERSISTENT SPECTRUM OF THE DIPPING LOW-MASS X-RAY BINARY 1A 1744-361

    SciTech Connect

    Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip

    2012-07-01

    We report on Chandra X-ray Observatory (Chandra) High Energy Transmission Grating spectra of the dipping low-mass X-ray binary 1A 1744-361 during its 2008 July outburst. We find that its persistent emission is well modeled by a blackbody (kT {approx} 1.0 keV) plus power law ({Gamma} {approx} 1.7) with an absorption edge. In the residuals of the combined spectrum, we find a significant absorption line at 6.961 {+-} 0.002 keV, consistent with the Fe XXVI (hydrogen-like Fe) 2-1 transition. We place an upper limit on the velocity of a redshifted flow of v < 221 km s{sup -1}. We find an equivalent width for the line of 27{sup +2}{sub -3} eV, from which we determine a column density of (7 {+-} 1) Multiplication-Sign 10{sup 17} cm{sup -2} via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of >10{sup 3.6} erg cm s{sup -1}. We discuss what implications the feature has on the system and its geometry. We also present Rossi X-ray Timing Explorer data accumulated during this latest outburst and, via an updated color-color diagram, clearly show that 1A 1744-361 is an 'atoll' source.

  13. Direct determination of radionuclides in building materials with self-absorption correction for the 63 and 186 keV γ-energy lines.

    PubMed

    Długosz-Lisiecka, Magdalena; Ziomek, Martyna

    2015-12-01

    The use of 911 keV and 129 keV γ-line intensity ratio has been applied for self-absorption correction of the 63 keV (234)Th ((238)U) and 186 keV((226)Ra and (235)U) lines in typical building materials and soil samples. Proposed procedure allows to determine (238)U from the (234)Th line (63 keV) and (226)Ra after subtraction of (235)U interference in the 186 keV. It is important in the case of low uranium concentration and weak intensity of (235)U 143 keV γ energy line, when activity of this radionuclide can be apprised on the natural constant (238)U/(235)U ratio, only (excluding accidental anthropogenic depleted uranium deposition in the soil samples). Therefore, by this method a direct and fast determination of the (226)Ra and other important radionuclides, without one month waiting period for (226)Ra-(222)Rn daughter equilibrium, is possible. The accuracy of the method has been confirmed (relative relation deviation <10%) for typical buildings materials such as: tales, bricks, concrete blocks and various type of ceramic materials.

  14. Direct determination of radionuclides in building materials with self-absorption correction for the 63 and 186 keV γ-energy lines.

    PubMed

    Długosz-Lisiecka, Magdalena; Ziomek, Martyna

    2015-12-01

    The use of 911 keV and 129 keV γ-line intensity ratio has been applied for self-absorption correction of the 63 keV (234)Th ((238)U) and 186 keV((226)Ra and (235)U) lines in typical building materials and soil samples. Proposed procedure allows to determine (238)U from the (234)Th line (63 keV) and (226)Ra after subtraction of (235)U interference in the 186 keV. It is important in the case of low uranium concentration and weak intensity of (235)U 143 keV γ energy line, when activity of this radionuclide can be apprised on the natural constant (238)U/(235)U ratio, only (excluding accidental anthropogenic depleted uranium deposition in the soil samples). Therefore, by this method a direct and fast determination of the (226)Ra and other important radionuclides, without one month waiting period for (226)Ra-(222)Rn daughter equilibrium, is possible. The accuracy of the method has been confirmed (relative relation deviation <10%) for typical buildings materials such as: tales, bricks, concrete blocks and various type of ceramic materials. PMID:26275363

  15. Nanoscale elemental sensitivity study of Nd₂Fe₁₄B using absorption correlation tomography.

    PubMed

    Kao, Thomas L; Shi, Crystal Y; Wang, Junyue; Mao, Wendy L; Liu, Yijin; Yang, Wenge

    2013-11-01

    Transmission X-ray microscopy (TXM) is a rapidly developing technique with the capability of nanoscale three dimensional (3D) real-space imaging. Combined with the wide range in energy tunability from synchrotron sources, TXM enables the retrieval of 3D microstructural information with elemental/chemical sensitivity that would otherwise be inaccessible. The differential absorption contrast above and below absorption edges has been used to reconstruct the distributions of different elements, assuming the absorption edges of the interested elements are fairly well separated. Here we present an "Absorption Correlation Tomography" (ACT) method based on the correlation of the material absorption across multiple edges. ACT overcomes the significant limitation caused by overlapping absorption edges, significantly expands the capabilities of TXM, and makes it possible for fully quantitative nano-scale 3D structural investigation with chemical/elemental sensitivity. The capability and robustness of this new methodology is demonstrated in a case study of an important type of rare earth magnet (Nd₂Fe₁₄B). PMID:23922210

  16. One- and two-photon absorption of a spiropyran-merocyanine system: experimental and theoretical studies.

    PubMed

    Matczyszyn, Katarzyna; Olesiak-Banska, Joanna; Nakatani, Keitaro; Yu, Pei; Murugan, N Arul; Zaleśny, Robert; Roztoczyńska, Agnieszka; Bednarska, Joanna; Bartkowiak, Wojciech; Kongsted, Jacob; Ågren, Hans; Samoć, Marek

    2015-01-29

    We report on the nonlinear optical properties measurements and quantum-chemical calculations of a well-known photochromic system consisting of spiropyran and the merocyanine photoproduct. The study of nonlinear absorption and refraction properties of the molecules dissolved in chloroform were performed with the Z-scan technique, using femtosecond pulses in a wide range of wavelengths. Maxima in the two-photon absorption spectrum at 700 and 1050 nm were found for the merocyanine form, and the corresponding two-photon absorption cross section is 80 GM and 20 GM, respectively. The latter feature does not vanish completely in the nonlinear spectrum of the spiropyran form, possibly because of the existence of some photoconversion caused by the laser beam during the measurements. A nonlinear absorption peak at 900 nm is found in the spiropyran form with an effective cross section of about 20 GM; it is likely due to three-photon absorption or to absorption by some intermediate species. The experimental data are supported by calculations performed with the use of a hybrid quantum mechanics-molecular mechanics approach. PMID:25531561

  17. Simulated biological materials for electromagnetic radiation absorption studies

    SciTech Connect

    Hartsgrove, G.; Kraszewski, A.; Surowiec, A.

    1987-01-01

    For the study of electromagnetic dosimetry and hyperthermia, it is necessary to simulate human biological materials. This can be done by chemical mixtures that are described in this paper. Formulas are presented for simulating bone, lung, brain, and muscle tissue in the frequency range of 100 MHz to 1 GHz. By using these preparations a realistic equivalent to the human body can be constructed.

  18. QED Theory of Radiation Emission and Absorption Lines for Atoms and Ions in a Strong Laser Field

    SciTech Connect

    Glushkov, A. V.

    2008-10-22

    The results of numerical calculating the multi-photon resonance shift and width for transition 6S-6F in the atom of Cs (wavelength 1059nm) in a laser pulse of the Gaussian and soliton-like shapes are presented. QED theory of radiation atomic lines is used.

  19. New on-line method for water isotope analysis of speleothem fluid inclusions using laser absorption spectroscopy (WS-CRDS)

    NASA Astrophysics Data System (ADS)

    Affolter, S.; Fleitmann, D.; Leuenberger, M.

    2014-01-01

    A new online method to analyse water isotopes of speleothem fluid inclusions using a wavelength scanned cavity ring down spectroscopy (WS-CRDS) instrument is presented. This novel technique allows us to simultaneously measure hydrogen and oxygen isotopes for a released aliquot of water. To do so, we designed a new simple line that allows the on-line water extraction and isotope analysis of speleothem samples. The specificity of the method lies in the fact that fluid inclusions release is made on a standard water background, which mainly improves the δD reliability. To saturate the line, a peristaltic pump continuously injects standard water into the line that is permanently heated to 140 °C and flushed with dry nitrogen gas. This permits instantaneous and complete vaporisation of the standard water resulting in an artificial water background with well-known δD and δ18O values. The speleothem sample is placed into a copper tube, attached to the line and after system stabilisation is crushed using a simple hydraulic device to liberate speleothem fluid inclusions water. The released water is carried by the nitrogen/standard water gas stream directly to a Picarro L1102-i for isotope determination. To test the accuracy and reproducibility of the line and to measure standard water during speleothem measurements a syringe injection unit was added to the line. Peak evaluation is done similarly as in gas chromatography to obtain δD and δ18O isotopic composition of measured water aliquots. Precision is better than 1.5‰ for δD and 0.4‰ for δ18O for water measurement for an extended range (-210 to 0‰ for δD and -27 to 0‰ for δ18O) primarily dependent on the amount of water released from speleothem fluid inclusions and secondarily on the isotopic composition of the sample. The results show that WS-CRDS technology is suitable for speleothem fluid inclusion measurements and gives results that are comparable to Isotope Ratio Mass Spectrometry (IRMS) technique.

  20. Studies of Microwave Absorption Properties of Carbon Nanotubes/Epoxy Composites

    NASA Astrophysics Data System (ADS)

    Zhao, Guang-Lin

    2010-10-01

    Less weight, excellent mechanical properties, and high efficiency in absorbing electromagnetic (EM) wave make carbon nanotubes (CNTs) composites attractive for microwave technology applications. Multi-walled carbon nanotubes (MWNTs) have much higher performance-to-price ratio (PPR) than SWNTs do in the composite applications. In this work, we aim to study the effect of the outside diameter (OD) distributions of MWNTs on their microwave absorption properties. We have fabricated six groups of carbon nanotube/epoxy composite samples with various OD distributions. The weight percentages of MWNTs in the composites were controlled in the range from 1 to 10%. We utilized a microwave resonant cavity technique to measure the microwave absorption properties of all the sixty samples around the central frequency of 9.968 GHz. Our results have shown that the maxima of EM wave absorptions for the six groups of samples were all around 7% MWNTs weight percentage. We further studied the effective attenuations of the electric and magnetic fields in six groups of MWNT composite samples with the same (7 %) MWNT blend in epoxy. The results show that, in general, the MWNTs with smaller diameters have higher microwave absorption at 9.968 GHz. However, sample group M5 (OD<8nm) shows unusual results, a lower microwave absorption than the other samples. We then used a scanning electron microscope (SEM) to study the morphologies of the MWNT samples. Based on the SEM analysis and microwave absorption measurements, we found that the efficiency of the microwave absorption of MWNT/Epoxy composites is strongly affected by the morphologies/structures of MWNTs in individual bundles.

  1. On-line precipitation/dissolution system for the preconcentration and determination of manganese traces by atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Dittfurth, Carola; Ballesteros, Evaristo; Gallego, Mercedes; Valcárcel, Miguel

    1996-12-01

    Flame atomic absorption spectrometry was used for the determination of Mn in biological material following preconcentration by precipitation. The proposed preconcentration method is based on the continuous precipitation of Mn(II) as hydrated Mn(IV) oxide in ammonia buffer and dissolution of the precipitate with hydrogen oxalate or dilute nitric acid. The sensitivity of the Mn determination is increased by the presence of hydrogen peroxide, which raises the rate of oxidation of Mn(II) to Mn(IV). By using a time-based technique (at a sample loading rate of 4 ml min -1) a concentration factor of up to 55 was obtained using 24 ml of sample. The effect of concurrent cations was investigated; the most adverse effect was exerted by Fe(III), which interfered at concentrations 50 times higher than that of Mn(II).

  2. Precise limits on cosmological variability of the fine-structure constant with zinc and chromium quasar absorption lines

    NASA Astrophysics Data System (ADS)

    Murphy, Michael T.; Malec, Adrian L.; Prochaska, J. Xavier

    2016-09-01

    The strongest transitions of Zn and Cr II are the most sensitive to relative variations in the fine-structure constant (Δα/α) among the transitions commonly observed in quasar absorption spectra. They also lie within just 40 Å of each other (rest frame), so they are resistant to the main systematic error affecting most previous measurements of Δα/α: long-range distortions of the wavelength calibration. While Zn and Cr II absorption is normally very weak in quasar spectra, we obtained high signal-to-noise, high-resolution echelle spectra from the Keck and Very Large Telescopes of nine rare systems where it is strong enough to constrain Δα/α from these species alone. These provide 12 independent measurements (three quasars were observed with both telescopes) at redshifts 1.0-2.4, 11 of which pass stringent reliability criteria. These 11 are all consistent with Δα/α = 0 within their individual uncertainties of 3.5-13 parts per million (ppm), with a weighted mean Δα/α = 0.4 ± 1.4stat ± 0.9sys ppm (1σ statistical and systematic uncertainties), indicating no significant cosmological variations in α. This is the first statistical sample of absorbers that is resistant to long-range calibration distortions (at the <1 ppm level), with a precision comparable to previous large samples of ˜150 (distortion-affected) absorbers. Our systematic error budget is instead dominated by much shorter range distortions repeated across echelle orders of individual spectra.

  3. An Fe XXVI Absorption Line in the Persistent Spectrum of the Dipping Low Mass X-ray Binary 1A 1744-361

    NASA Technical Reports Server (NTRS)

    Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip

    2009-01-01

    We report on Chandra X-ray Observatory (CXO) High-Energy Transmission Grating (HETG) spectra of the dipping Low Mass X-ray Binary (LMXB) 1A 1744-361 during its July 2008 outburst. We find that its persistent emission is well modeled by a blackbody (kT approx. 1.0 keV) plus power-law (Gamma approx. 1.7) with an absorption edge at 7.6 keV. In the residuals of the combined spectrum we find a significant absorption line at 6.961+/-0.002 keV, consistent with the Fe XXVI (hydrogen-like Fe) 2 - 1 transition. We place an upper limit on the velocity of a redshifted flow of v < 221 km/s. We find an equivalent width for the line of 27+2/-3 eV, from which we determine a column density of 7+/-1 x 10(exp 17)/sq cm via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of > 10(exp 3.6) erg cm/s. The properties of this line are consistent with those observed in other dipping LMXBs. Using Rossi X-ray Timing Explorer (RXTE) data accumulated during this latest outburst we present an updated color-color diagram which clearly shows that IA 1744-361 is an "atoll" source. Finally, using additional dips found in the RXTE and CXO data we provide an updated orbital period estimate of 52+/-5 minutes.

  4. The fundamental quadrupole band of (N-14)2 - Line positions from high-resolution stratospheric solar absorption spectra

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Zander, R.; Goldman, A.; Murcray, F. J.; Murcray, D. G.; Gunson, M. R.; Farmer, C. B.

    1991-01-01

    Accurate measurements of the positions of O- and S-branch lines of the (1-0) vibration-rotation quadrupole band of molecular nitrogen (N-14)2 are reported. Improved Dunham coefficients were derived from a simultaneous least squares analysis of these measurements and selected infrared and far infrared data. The new measurements were performed using stratospheric solar occultation spectra recorded with Fourier transform spectrometer instruments, operated at unapodized spectral resolutions of 0.002 and 0.01/cm.

  5. An HST/COS observation of broad Lyα emission and associated absorption lines of the BL Lacertae object H 2356-309

    SciTech Connect

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

    2014-11-01

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

  6. Microwave Absorption Study on (Bi, Pb)-Sr-Ca-Cu-O Granular Superconductors

    NASA Astrophysics Data System (ADS)

    Jurga, W.; Piekara-Sady, L.; Gazda, M.

    2008-07-01

    (Bi, Pb)-Sr-Ca-Cu-O is considered as a system of 2201, 2212 and 2223 superconductors embedded in the insulating matrix. The size of the grains depends on the time of recrystallization. These types of ceramics exhibit a two-step transition to superconducting state. Because electrical properties depend among other on the Josephson coupling between grains, the magnetically modulated microwave absorption study was undertaken. Magnetically modulated microwave absorption signal was observed to arise just as temperature had been lowered below T1. The shape of this signal was studied to recognize the second temperature T2. Some strong oscillations appear on magnetically modulated microwave absorption at lower temperatures, which might be related to local percolation breakdown in superconducting network.

  7. Particle scattering, backscattering, and absorption coefficients: An in situ closure and sensitivity study

    NASA Astrophysics Data System (ADS)

    Wex, Heike; Neusüß, Christian; Wendisch, Manfred; Stratmann, Frank; Koziar, Christian; Keil, Andreas; Wiedensohler, Alfred; Ebert, Martin

    2002-11-01

    Comparisons between measured and calculated aerosol scattering, backscattering, and absorption coefficients were made based on in situ, ground-based measurements during the Melpitz INTensive (MINT) and Lindenberg Aerosol Characterization Experiment 1998 (LACE 98) field studies. Furthermore, airborne measurements made with the same type of instruments are reviewed and compared with the ground-based measurements. Agreement between measured and calculated values is on the order of ±20% for scattering and backscattering coefficients. A sensitivity analysis showed a large influence on the calculated particle scattering and backscattering coefficients resulting from sizing uncertainties in the measured number size distributions. Measured absorption coefficients were significantly smaller than the corresponding calculated values. The largest uncertainty for the calculated absorption coefficients resulted from the size-dependent fraction of elemental carbon (EC) of the aerosol. A correction for the measured fractions of EC could significantly improve the agreement between measured and calculated absorption coefficients. The overall uncertainty of the calculated values was investigated with a Monte Carlo method by simultaneously and randomly varying the input parameters of the calculations, where the variation of each parameter was bounded by its uncertainty. The measurements were mostly found to be within the range of uncertainties of the calculations, with uncertainties for the calculated scattering and backscattering coefficients of about ±20% and for the absorption coefficients of about ±30%. Thus, to increase the accuracy of calculated scattering, backscattering, and absorption coefficients, it is crucial to further reduce the error in particle number size distribution measurement techniques. In addition, further improvement of the techniques for measuring absorption coefficients and further investigation of the measurement of the fraction of EC of the aerosol is

  8. Flow injection determination of copper in mussels by flame atomic absorption spectrometry after on-line continuous ultrasound-assisted extraction

    NASA Astrophysics Data System (ADS)

    Moreno-Cid, A.; Yebra, M. C.

    2002-05-01

    Copper was extracted on-line from solid mussel samples by a simple and rapid continuous ultrasound-assisted extraction system (CUES). The CUES is connected to a flow injection manifold, which permits the on-line flame atomic absorption spectrometric determination of copper. The manifold is simple and the copper signal was obtained for a volume of 250 μl of acid leachate injected into an ultrapure water carrier stream. An experimental design was used for the optimization of the continuous leaching procedure. Compared to off-line ultrasonic-assisted extraction methods, sonication time is reduced by factors of 6-12, the leaching takes place at room temperature (20 °C), and the analysis time is reduced because centrifugation was not necessary to separate the liquid phase. The method allowed a total sampling frequency of 11 samples h -1, with a relative standard deviation for the complete procedure of 2.7% (for a sample containing 2.0 μg g -1 copper (wet mass, n=11). The limit of detection was 0.06 μg g -1 (wet mass) for 30 mg of sample. The analytical procedure was verified for a reference standard material (TORT-1). The analytical procedure was applied to mussel samples from Galicia (Spain).

  9. NONLINEAR COLOR-METALLICITY RELATIONS OF GLOBULAR CLUSTERS. V. NONLINEAR ABSORPTION-LINE INDEX VERSUS METALLICITY RELATIONS AND BIMODAL INDEX DISTRIBUTIONS OF M31 GLOBULAR CLUSTERS

    SciTech Connect

    Kim, Sooyoung; Yoon, Suk-Jin; Chung, Chul; Lee, Young-Wook; Caldwell, Nelson; Schiavon, Ricardo P.; Kang, Yongbeom; Rey, Soo-Chang

    2013-05-10

    Recent spectroscopy on the globular cluster (GC) system of M31 with unprecedented precision witnessed a clear bimodality in absorption-line index distributions of old GCs. Such division of extragalactic GCs, so far asserted mainly by photometric color bimodality, has been viewed as the presence of merely two distinct metallicity subgroups within individual galaxies and forms a critical backbone of various galaxy formation theories. Given that spectroscopy is a more detailed probe into stellar population than photometry, the discovery of index bimodality may point to the very existence of dual GC populations. However, here we show that the observed spectroscopic dichotomy of M31 GCs emerges due to the nonlinear nature of metallicity-to-index conversion and thus one does not necessarily have to invoke two separate GC subsystems. We take this as a close analogy to the recent view that metallicity-color nonlinearity is primarily responsible for observed GC color bimodality. We also demonstrate that the metallicity-sensitive magnesium line displays non-negligible metallicity-index nonlinearity and Balmer lines show rather strong nonlinearity. This gives rise to bimodal index distributions, which are routinely interpreted as bimodal metallicity distributions, not considering metallicity-index nonlinearity. Our findings give a new insight into the constitution of M31's GC system, which could change much of the current thought on the formation of GC systems and their host galaxies.

  10. Feasibility of a 3D human airway epithelial model to study respiratory absorption.

    PubMed

    Reus, Astrid A; Maas, Wilfred J M; Jansen, Harm T; Constant, Samuel; Staal, Yvonne C M; van Triel, Jos J; Kuper, C Frieke

    2014-03-01

    The respiratory route is an important portal for human exposure to a large variety of substances. Consequently, there is an urgent need for realistic in vitro strategies for evaluation of the absorption of airborne substances with regard to safety and efficacy assessment. The present study investigated feasibility of a 3D human airway epithelial model to study respiratory absorption, in particular to differentiate between low and high absorption of substances. Bronchial epithelial models (MucilAir™), cultured at the air-liquid interface, were exposed to eight radiolabeled model substances via the apical epithelial surface. Absorption was evaluated by measuring radioactivity in the apical compartment, the epithelial cells and the basolateral culture medium. Antipyrine, caffeine, naproxen and propranolol were highly transported across the epithelial cell layer (>5%), whereas atenolol, mannitol, PEG-400 and insulin were limitedly transported (<5%). Results indicate that the 3D human airway epithelial model used in this study is able to differentiate between substances with low and high absorption. The intra-experimental reproducibility of the results was considered adequate based on an average coefficient of variation (CV) of 15%. The inter-experimental reproducibility of highly absorbed compounds was in a similar range (CV of 15%), but this value was considerably higher for those compounds that were limitedly absorbed. No statistical significant differences between different donors and experiments were observed. The present study provides a simple method transposable in any lab, which can be used to rank the absorption of chemicals and pharmaceuticals, and is ready for further validation with respect to reproducibility and capacity of the method to predict respiratory transport in humans.

  11. Determination and interference studies of bismuth by tungsten trap hydride generation atomic absorption spectrometry.

    PubMed

    Kula, Ibrahim; Arslan, Yasin; Bakirdere, Sezgin; Titretir, Serap; Kendüzler, Erdal; Ataman, O Yavuz

    2009-11-15

    The determination of bismuth requires sufficiently sensitive procedures for detection at the microg L(-1) level or lower. W-coil was used for on-line trapping of volatile bismuth species using HGAAS (hydride generation atomic absorption spectrometry); atom trapping using a W-coil consists of three steps. Initially BiH(3) gas is formed by hydride generation procedure. The analyte species in vapor form are transported through the W-coil trap held at 289 degrees C where trapping takes place. Following the preconcentration step, the W-coil is heated to 1348 degrees C; analyte species are released and transported to flame-heated quartz atom cell where the atomic signal is formed. In our study, interferences have been investigated in detail during Bi determination by hydride generation, both with and without trap in the same HGAAS system. Interferent/analyte (mass/mass) ratio was kept at 1, 10 and 100. Experiments were designed for carrier solutions having 1.0M HNO(3). Interferents such as Fe, Mn, Zn, Ni, Cu, As, Se, Cd, Pb, Au, Na, Mg, Ca, chloride, sulfate and phosphate were examined. The calibration plot for an 8.0 mL sampling volume was linear between 0.10 microg L(-1) and 10.0 microg L(-1) of Bi. The detection limit (3s/m) was 25 ng L(-1). The enhancement factor for the characteristic concentration (C(o)) was found to be 21 when compared with the regular system without trap, by using peak height values. The validation of the procedure was performed by the analysis of the certified water reference material and the result was found to be in good agreement with the certified values at the 95% confidence level.

  12. Ultrafast Excited-State Dynamics of 6-Azauracil Studied by Femtosecond Transient Absorption Spectroscopy.

    PubMed

    Hua, XinZhong; Hua, LinQiang; Liu, XiaoJun

    2015-12-31

    The excited-state dynamics of 6-azauracil in different solvents have been studied using femtosecond transient absorption spectroscopy. The molecule is populated to the S2 state with a pump pulse at 264 nm. Broad-band white light continuum which covers from 320 to 600 nm is used as the probe. With a global fitting analysis of the measured transient spectra, three decay time constants, i.e., <0.3, 5.2 ± 0.1, and >1000 ps, are directly obtained in the solvent of acetonitrile. These newly observed lifetime constants are important in clarifying its decay dynamics as well as in providing a criterion for the ultrafast dynamics simulations in 6-azauracil using quantum chemical theories. In combination with previous theoretical works, the main decay channel is proposed: the initially populated S2 decays to S1 through internal conversion in <0.3 ps, followed by an intersystem crossing from S1 to T1 in 5.2 ± 0.1 ps. The >1000 ps component is due to the decay of the T1 state. A comparison of the excited-state dynamics in different solvents reveals that the decay from S1 to T1 shows a clear dependence on the polarity of the solvents. With higher polarity, the S1 excited state decays faster. This observation is in line with the prediction by Etinski et al. [ Phys. Chem. Chem. Phys. 2010 , 12 , 15665 - 15671 ], where a blue-shift of the T1 state potential energy surface leading to an increase of the intersystem crossing rate was proposed. With the new information obtained in the present measurement, a clearer picture of the decay dynamics of 6-azauracil on the S2 excited state is provided.

  13. Pressure Sounding of the Middle Atmosphere from ATMOS Solar Occultation Measurements of Atmospheric CO(sub 2) Absorption Lines

    NASA Technical Reports Server (NTRS)

    Abrams, M.; Gunson, M.; Lowes, L.; Rinsland, C.; Zander, R.

    1994-01-01

    A method for retrieving the atmospheric pressure corresponding to the tangent point of an infrared spectrum recorded in the solar occultation mode is described and applied to measurements made by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer. Tangent pressure values are inferred from measurements of isolated CO(sub 2) lines with temperature-insensitive intensities. Tangent pressures are determined with a spectroscopic precision of 1-3%, corresponding to a tangent point height precision, depending on the scale height, of 70-210 meters.

  14. Real-time calibration of laser absorption spectrometer using spectral correlation performed with an in-line gas cell.

    PubMed

    Smith, Clinton J; Wang, Wen; Wysocki, Gerard

    2013-09-23

    A real-time drift correction and calibration method using spectral correlation based on a revolving in-line gas cell for laser-based spectroscopic trace-gas measurements has been developed and evaluated experimentally. This technique is relatively simple to implement in laser spectroscopy systems and assures long-term stability of trace-gas measurements by minimizing the effects of external sources of drift in real-time. Spectroscopic sensitivity sufficient for environmental monitoring and effective drift suppression has been achieved for long-term measurements of CO₂ with a quantum cascade laser based spectrometer.

  15. Study of interstellar molecular clouds using formaldehyde absorption toward extragalactic radio sources

    SciTech Connect

    Araya, E. D.; Andreev, N.; Dieter-Conklin, N.; Goss, W. M.

    2014-04-01

    We present new Very Large Array 6 cm H{sub 2}CO observations toward four extragalactic radio continuum sources (B0212+735, 3C 111, NRAO 150, and BL Lac) to explore the structure of foreground Galactic clouds as revealed by absorption variability. This project adds a new epoch in the monitoring observations of the sources reported by Marscher and collaborators in the mid-1990s. Our new observations confirm the monotonic increase in H{sub 2}CO absorption strength toward NRAO 150. We do not detect significant variability of our 2009 spectra with respect to the 1994 spectra of 3C111, B0212+735, and BL Lac; however, we find significant variability of the 3C111 2009 spectrum with respect to archive observations conducted in 1991 and 1992. Our analysis supports that changes in absorption lines could be caused by chemical and/or geometrical gradients in the foreground clouds and not necessarily by small-scale (∼10 AU) high-density molecular clumps within the clouds.

  16. A study of variations in the 787-nm ammonia absorption band in the Jupiter atmosphere

    NASA Astrophysics Data System (ADS)

    Bondarenko, N. N.

    2013-08-01

    During the last years the program of the spectrophotometric study of Jupiter included the measurements of the NH3 absorption band 787 nm. This band is overlapped by a broader absorption band of CH4. To detect the NH3 band we used the ratio of Jovian spectra to the spectrum of Saturn equatorial region. It was taken into account that the ammonia absorption on Saturn is significantly weaker than on Jupiter. The results of processing the spectrograms were analyzed for the years 2007-2010. Latitudinal variations of the NH3 band regularly show a depression of absorption at low and temperate latitudes of Jovian northern hemisphere. The equivalent width decreases approximately from 18-16 Å, to 14-12 Å. A more or less symmetric and steeper decrease of absorption from the disk center to limbs was obtained for the equatorial belt of Jupiter. It may be considered as evidence of the reality of that latitudinal depression but not the instrumental errors. It should be noted that the ammonia decrease in northern hemisphere was detected also from radio observations of Jupiter

  17. A Study on the Excitation and Resonant Absorption of Coronal Loop Kink Oscillations

    NASA Astrophysics Data System (ADS)

    Yu, Dae Jung; Van Doorsselaere, Tom

    2016-11-01

    We study theoretically the issue of externally driven excitations of standing kink waves and their resonant absorption into torsionally polarized m = 1 waves in the coronal loops in pressureless plasmas. We use the ideal MHD equations, for which we develop an invariant imbedding method available in cylindrical geometry. We assume a sinusoidal density profile at the loop boundary where the density inside the loop is lower than the outside and vice versa. We present field distributions for these two cases and find that they have similar behaviors. We compare the results for the overdense loops, which describe the usual coronal loops, with the analytical solutions of Soler et al. obtained using the Frobenius method. Our results show some similarity for thin nonuniform layers but deviate a lot for thick nonuniform layers. For the first case, which describes the wave train propagation in funnels, we find that resonant absorption depends crucially on the thickness of the nonuniform boundary, loop length, and density contrast. The resonant absorption of the kink mode is dominant when the loop length is sufficiently larger compared with its radius (thin loop). The behavior of the far-field pattern of the scattered wave by the coronal loop is closely related to that of the resonant absorption. For the mode conversion phenomena in inhomogeneous plasmas, a certain universal behavior of the resonant absorption is found for the first time. We expect that the main feature may also apply to the overdense loops and discuss its relation to the damping rate.

  18. Iron absorption in raw and cooked bananas: a field study using stable isotopes in women

    PubMed Central

    García, Olga P.; Martínez, Mara; Romano, Diana; Camacho, Mariela; de Moura, Fabiana F.; Abrams, Steve A.; Khanna, Harjeet K.; Dale, James L.; Rosado, Jorge L.

    2015-01-01

    Background Banana is a staple food in many regions with high iron deficiency and may be a potential vehicle for iron fortification. However, iron absorption from bananas is not known. Objective The objective of this study was to evaluate total iron absorption from raw and cooked bananas. Design Thirty women (34.9±6.6 years) from rural Mexico were randomly assigned to one of two groups each consuming: 1) 480 g/day of raw banana for 6 days, or 2) 500 g/day of cooked banana for 4 days. Iron absorption was measured after extrinsically labeling with 2 mg of 58Fe and a reference dose of 6 mg 57Fe; analysis was done using ICP-MS. Results Iron content in cooked bananas was significantly higher than raw bananas (0.53 mg/100 g bananas vs. 0.33 mg/100 mg bananas, respectively) (p<0.001). Percent iron absorption was significantly higher in raw bananas (49.3±21.3%) compared with cooked banana (33.9±16.2%) (p=0.035). Total amount of iron absorbed from raw and cooked bananas was similar (0.77±0.33 mg vs. 0.86±0.41 mg, respectively). Conclusion Total amount of absorbed iron is similar between cooked and raw bananas. The banana matrix does not affect iron absorption and is therefore a potential effective target for genetic modification for iron biofortification. PMID:25660254

  19. [Comparation of gastrointestinal absorption studies of specnuezhenide with salidroside in rats].

    PubMed

    Li, Hui-Fen; Zhang, Xue-Lan

    2014-03-01

    The experiment was designed to study the mechanism of increasing efficiency of Ligustrum lucidum steamed with wine. Rats in vivo with gastrointestinal perfusion model were used. The contents of salidroside and specnuezhenide in the fluid of gastrointestinal perfusion of rats were measured by HPLC at different time points after dosing. Then the K(a) and absorption percentage were calculated. Specnuezhenide could be detected in the fluid of gastrointestinal perfusion of specnuezhenide. The K(a) of the specnuezhenide and salidroside in the fetal intestines are 0.055 3 and 0.144 2 h(-1) respectively and the total absorptivity are 24.46% and 60.14% respectively after 4 hours. The K(a) in the stomach are 5.70 and 8.26 h(-1) respectively and the total absorptivity are 34.21% and 47.23% respectively after 4 hours. The experiment proved that specnuezhenide can be metabolized into salidroside which is more beneficial for gastrointestinal absorption. The experiment proved that specnuezhenide can be metabolized into salidroside both in the rat's stomach and the fetal intestine and compared with the specnuezhenide salidroside is more conducive to gastrointestinal absorption. The results suggested that the increasing efficiency on liver and kidney of L. lucidum steamed with wine has business with the fact that Specnuezhe nide is more conducive to the body after it is changed into salidroside. PMID:24956860

  20. X-ray absorption study of the electronic structure of Mn-doped amorphous Si

    SciTech Connect

    Arenholz, Elke; Zeng, Li; Huegel, A.; Helgren, E.; Hellman, F.; Piamonteze, C.; Arenholz, E.

    2008-03-08

    The electronic structure of Mn in amorphous Si (a-Mn{sub x}Si{sub 1?x}) is studied by X-ray absorption spectroscopy at the Mn L{sub 3,2} edges for x = 0.005-0.18. Except the x = 0.005 sample, which shows a slight signature of Mn{sup 2+} atomic multiplets associated with a local Mn moment, all samples have broad and featureless L{sub 3,2} absorption peaks, corresponding to an itinerant state for all 3d electrons. The broad X-ray absorption spectra exclude the possibility of a localized 3d moment and explain the unexpectedly quenched Mn moment in this magnetically-doped amorphous semiconductor. Such a fully delocalized d state of Mn dopant in Si has not been previously suggested.

  1. Numerical study of plasmonic absorption enhancement in semiconductor absorbers by metallic nanoparticles

    NASA Astrophysics Data System (ADS)

    Hornich, Julian; Pflaum, Christoph; Brabec, Christoph; Forberich, Karen

    2016-09-01

    We are studying the influence of spherical silver nanoparticles (AgNP) in absorbing media by numerically solving the Maxwell's equations. Our simulations show that the near-field absorption enhancement introduced by a single AgNP in the surrounding medium is increasing with the growing particle diameter. However, we observe that the relative absorption per particle volume is on a similar level for different particle sizes; hence, different numbers of particles with the same total volume yield the same near-field absorption enhancement. We also investigate the effect of non-absorbing shells around the AgNP with the conclusion that even very thin shells suppress the beneficial effects of the particles noticeably. Additionally, we include AgNP in an organic solar cell at different vertical positions with different particle spacings and observe the beneficial effects for small AgNP and the scattering dependent performance for larger particles.

  2. Studies of Water Absorption Behavior of Plant Fibers at Different Temperatures

    NASA Astrophysics Data System (ADS)

    Saikia, Dip

    2010-05-01

    Moisture absorption of natural fiber plastic composites is one major concern in their outdoor applications. The absorbed moisture has many detrimental effects on the mechanical performance of these composites. A knowledge of the moisture diffusivity, permeability, and solubility is very much essential for the application of natural fibers as an excellent reinforcement in polymers. An effort has been made to study the water absorption behavior of some natural fibers such as bowstring hemp, okra, and betel nut at different temperatures to improve the long-term performance of composites reinforced with these fibers. The gain in moisture content in the fibers due to water absorption was measured as a function of exposure time at temperatures ranging from 300 K to 340 K. The thermodynamic parameters of the sorption process, such as diffusion coefficients and corresponding activation energies, were estimated.

  3. [Study on transient absorption spectrum of tungsten nanoparticle with HepG2 tumor cell].

    PubMed

    Cao, Lin; Shu, Xiao-Ning; Liang, Dong; Wang, Cong

    2014-07-01

    Significance of this study lies in tungsten nano materials can be used as a preliminary innovative medicines applied basic research. This paper investigated the inhibition of tungsten nanoparticles which effected on human hepatoma HepG2 cells by MTT. The authors use transient absorption spectroscopy (TAS) technology absorption and emission spectra characterization of charge transfer between nanoparticles and tumor cell. The authors discussed the role of the tungsten nanoparticles in the tumor early detection of the disease and its anti-tumor properties. In the HepG2 experiments system, 100-150 microg x mL(-1) is the best drug concentration of anti-tumor activity which recact violently within 6 hours and basically completed in 24 hours. The results showed that transient absorption spectroscopy can be used as tumor detection methods and characterization of charge transfer between nano-biosensors and tumor cells. Tungsten nanoparticles have potential applications as anticancer drugs.

  4. Optical absorption and luminescence studies of fast neutron-irradiated complex oxides for jewellery applications

    NASA Astrophysics Data System (ADS)

    Mironova-Ulmane, N.; Skvortsova, V.; Popov, A. I.

    2016-07-01

    We studied the optical absorption and luminescence of agate (SiO2), topaz (Al2[SiO4](F,OH)2), beryl (Be3Al2Si6O18), and prehnite (Ca2Al(AlSi3O10)(OH)2) doped with different concentrations of transition metal ions and exposed to fast neutron irradiation. The exchange interaction between the impurity ions and the defects arising under neutron irradiation causes additional absorption as well as bands' broadening in the crystals. These experimental results allow us to suggest the method for obtaining new radiation-defect induced jewellery colors of minerals due to neutron irradiation.

  5. Decomposition of NO studied by infrared emission and CO laser absorption

    NASA Technical Reports Server (NTRS)

    Hanson, R. K.; Monat, J. P.; Flower, W. L.; Kruger, C. H.

    1975-01-01

    A diagnostic technique for monitoring the concentration of NO using absorption of CO laser radiation has been developed and applied in a study of the decomposition kinetics of NO. Simultaneous measurements of infrared emission by NO at 5.3 microns were also made to validate the laser absorption technique. The data were obtained behind incident shocks in NO-N2O-Ar (or Kr) mixtures, with temperatures in the range 2400-4100 K. The rate constant for the dominant reaction of O and NO to yield N and O2 was inferred from comparisons with computer simulations of the reactive flow.

  6. Decomposition of NO studied by infrared emission and CO laser absorption

    NASA Technical Reports Server (NTRS)

    Hanson, R. K.; Flower, W. L.; Monat, J. P.; Kruger, C. H.

    1974-01-01

    A diagnostic technique for monitoring the concentration of NO using absorption of CO laser radiation was developed and applied in a study of the decomposition kinetics of NO. Simultaneous measurements of infrared emission by NO at 5.3 microns were also made to validate the laser absorption technique. The data were obtained behind incident shocks in NO-N2O-Ar (or Kr) mixtures, with temperatures in the range 2400-4100 K. Rate constants for dominant reactions were inferred from comparisons with computer simulations of the reactive flow.

  7. Non-degenerate two-photon absorption in silicon waveguides. Analytical and experimental study

    DOE PAGES

    Zhang, Yanbing; Husko, Chad; Lefrancois, Simon; Rey, Isabella H.; Krauss, Thomas F.; Schröder, Jochen; Eggleton, Benjamin J.

    2015-06-22

    We theoretically and experimentally investigate the nonlinear evolution of two optical pulses in a silicon waveguide. We provide an analytic solution for the weak probe wave undergoing non-degenerate two-photon absorption (TPA) from the strong pump. At larger pump intensities, we employ a numerical solution to study the interplay between TPA and photo-generated free carriers. We develop a simple and powerful approach to extract and separate out the distinct loss contributions of TPA and free-carrier absorption from readily available experimental data. Our analysis accounts accurately for experimental results in silicon photonic crystal waveguides.

  8. Where Do College Drinkers Draw the Line?: A Qualitative Study

    ERIC Educational Resources Information Center

    Terry, Danielle L.; Garey, Lorra; Carey, Kate B.

    2014-01-01

    Alcohol use among college students has received nationwide recognition as a public health concern. The primary aim of this study was to explore students' opinions of when drinking crosses the line from acceptable to unacceptable. This study used qualitative methods to: (a) examine unappealing aspects of drinking by relationship type…

  9. Limits on the time variation of the electromagnetic fine-structure constant in the low energy limit from absorption lines in the spectra of distant quasars.

    PubMed

    Srianand, R; Chand, H; Petitjean, P; Aracil, B

    2004-03-26

    We present the results of a detailed many-multiplet analysis performed on a new sample of Mg ii systems observed in high quality quasar spectra obtained using the Very Large Telescope. The weighted mean value of the variation in alpha derived from our analysis over the redshift range 0.4absorption line systems.

  10. Use of Muromac A-1 chelating resin for determination of copper and molybdenum in seawater by atomic absorption with on-line preconcentration

    NASA Astrophysics Data System (ADS)

    Sung, Yu-Hsiang; Liu, Zhen-Shan; Huang, Shang-Da

    1997-06-01

    Muromac A-1 chelating resin is used to preconcentrate trace metals (copper and molybdenum) in seawater. A miniature column (4-7 μl) packed with resin and a home-made automatic on-line preconcentration system for graphite furnance atomic absorption spectrometry (GFAAS) were used. This preconcentration system was modified from a Perkin-Elmer AS-40 autosampler by mounting a Muromac A-1 microcolumn near the tip of the autosampler capillary. The preconcentration procedure was performed by using a four-way distribution valve and a programmable controller. A sample volume of only 20-200 μl was required for determining copper and molybdenum in seawater. The calibration graph method was used; the detection limits for copper and molybdenum were 0.05 ppb and 0.25 ppb respectively. The sample throughput was 18-26 h -1. The accuracy of the method was confirmed by the analysis of certified reference saline waters.

  11. Polarization studies of Zeeman affected spectral lines using the MSFC magnetograph

    NASA Technical Reports Server (NTRS)

    Balasubramaniam, K. S.; West, E. A.

    1990-01-01

    The Marshall Space Flight Center (MSFC) vector magnetograph records polarization images of absorption lines that are sensitive to magnetic fields. A method is presented for analyzing the Stokes spectral-line profiles of a photospheric Fe I absorption line (5250.2 A) which is influenced by the Zeeman effect. Using nonlinear least-square optimization, the observed Stokes profiles are compared with those generated from the theoretical solution of the polarized radiative transfer equations. The optimization process accounts for the spectral convolution of the source and the MSFC vector magnetograph. The resulting physical properties of the active region producing the polarized light are discussed.

  12. Rest-UV Absorption Lines as Metallicity Estimator: The Metal Content of Star-forming Galaxies at z ~ 5

    NASA Astrophysics Data System (ADS)

    Faisst, A. L.; Capak, P. L.; Davidzon, I.; Salvato, M.; Laigle, C.; Ilbert, O.; Onodera, M.; Hasinger, G.; Kakazu, Y.; Masters, D.; McCracken, H. J.; Mobasher, B.; Sanders, D.; Silverman, J. D.; Yan, L.; Scoville, N. Z.

    2016-05-01

    We measure a relation between the depth of four prominent rest-UV absorption complexes and metallicity for local galaxies and verify it up to z˜ 3. We then apply this relation to a sample of 224 galaxies at 3.5\\lt z\\lt 6.0 (< z> =4.8) in the Cosmic Evolution Survey (COSMOS), for which unique UV spectra from the Deep Imaging Multi-object Spectrograph (DEIMOS) and accurate stellar masses from the Spitzer Large Area Survey with Hyper-Suprime-Cam (SPLASH) are available. The average galaxy population at z˜ 5 and {log}(M/{M}⊙ )\\gt 9 is characterized by 0.3-0.4 dex (in units of 12+{log}({{O/H}})) lower metallicities than at z ˜ 2, but comparable to z˜ 3.5. We find galaxies with weak or no Lyα emission to have metallicities comparable to z ˜ 2 galaxies and therefore may represent an evolved subpopulation of z˜ 5 galaxies. We find a correlation between metallicity and dust in good agreement with local galaxies and an inverse trend between metallicity and star-formation rate consistent with observations at z ˜ 2. The relation between stellar mass and metallicity (MZ relation) is similar to z˜ 3.5, but there are indications of it being slightly shallower, in particular for the young, Lyα-emitting galaxies. We show that, within a “bathtub” approach, a shallower MZ relation is expected in the case of a fast (exponential) build-up of stellar mass with an e-folding time of 100-200 Myr. Because of this fast evolution, the process of dust production and metal enrichment as a function of mass could be more stochastic in the first billion years of galaxy formation compared to later times.

  13. CHARACTERIZING THE CIRCUMGALACTIC MEDIUM OF NEARBY GALAXIES WITH HST/COS AND HST/STIS ABSORPTION-LINE SPECTROSCOPY

    SciTech Connect

    Stocke, John T.; Keeney, Brian A.; Danforth, Charles W.; Shull, J. Michael; Froning, Cynthia S.; Green, James C.; Penton, Steven V.; Savage, Blair D.

    2013-02-15

    The circumgalactic medium (CGM) of late-type galaxies is characterized using UV spectroscopy of 11 targeted QSO/galaxy pairs at z {<=} 0.02 with the Hubble Space Telescope Cosmic Origins Spectrograph (COS) and {approx}60 serendipitous absorber/galaxy pairs at z {<=} 0.2 with the Space Telescope Imaging Spectrograph. CGM warm cloud properties are derived, including volume filling factors of 3%-5%, cloud sizes of 0.1-30 kpc, masses of 10-10{sup 8} M {sub Sun }, and metallicities of {approx}0.1-1 Z {sub Sun }. Almost all warm CGM clouds within 0.5 R {sub vir} are metal-bearing and many have velocities consistent with being bound, 'galactic fountain' clouds. For galaxies with L {approx}> 0.1 L*, the total mass in these warm CGM clouds approaches 10{sup 10} M {sub Sun }, {approx}10%-15% of the total baryons in massive spirals and comparable to the baryons in their parent galaxy disks. This leaves {approx}> 50% of massive spiral-galaxy baryons 'missing'. Dwarfs (<0.1 L*) have smaller area covering factors and warm CGM masses ({<=}5% baryon fraction), suggesting that many of their warm clouds escape. Constant warm cloud internal pressures as a function of impact parameter (P/k {approx} 10 cm{sup -3} K) support the inference that previous COS detections of broad, shallow O VI and Ly{alpha} absorptions are of an extensive ({approx}400-600 kpc), hot (T Almost-Equal-To 10{sup 6} K), intra-cloud gas which is very massive ({>=}10{sup 11} M {sub Sun }). While the warm CGM clouds cannot account for all the 'missing baryons' in spirals, the hot intra-group gas can, and could account for {approx}20% of the cosmic baryon census at z {approx} 0 if this hot gas is ubiquitous among spiral groups.

  14. Rest-UV Absorption Lines as Metallicity Estimator: The Metal Content of Star-forming Galaxies at z ~ 5

    NASA Astrophysics Data System (ADS)

    Faisst, A. L.; Capak, P. L.; Davidzon, I.; Salvato, M.; Laigle, C.; Ilbert, O.; Onodera, M.; Hasinger, G.; Kakazu, Y.; Masters, D.; McCracken, H. J.; Mobasher, B.; Sanders, D.; Silverman, J. D.; Yan, L.; Scoville, N. Z.

    2016-05-01

    We measure a relation between the depth of four prominent rest-UV absorption complexes and metallicity for local galaxies and verify it up to z˜ 3. We then apply this relation to a sample of 224 galaxies at 3.5\\lt z\\lt 6.0 (< z> =4.8) in the Cosmic Evolution Survey (COSMOS), for which unique UV spectra from the Deep Imaging Multi-object Spectrograph (DEIMOS) and accurate stellar masses from the Spitzer Large Area Survey with Hyper-Suprime-Cam (SPLASH) are available. The average galaxy population at z˜ 5 and {log}(M/{M}ȯ )\\gt 9 is characterized by 0.3–0.4 dex (in units of 12+{log}({{O/H}})) lower metallicities than at z ˜ 2, but comparable to z˜ 3.5. We find galaxies with weak or no Lyα emission to have metallicities comparable to z ˜ 2 galaxies and therefore may represent an evolved subpopulation of z˜ 5 galaxies. We find a correlation between metallicity and dust in good agreement with local galaxies and an inverse trend between metallicity and star-formation rate consistent with observations at z ˜ 2. The relation between stellar mass and metallicity (MZ relation) is similar to z˜ 3.5, but there are indications of it being slightly shallower, in particular for the young, Lyα-emitting galaxies. We show that, within a “bathtub” approach, a shallower MZ relation is expected in the case of a fast (exponential) build-up of stellar mass with an e-folding time of 100–200 Myr. Because of this fast evolution, the process of dust production and metal enrichment as a function of mass could be more stochastic in the first billion years of galaxy formation compared to later times.

  15. Discovery of Associated Absorption Lines in an X-Ray Warm Absorber: Hubble Space Telescope Observations of PG 1114+445

    NASA Technical Reports Server (NTRS)

    Mathur, Smita; Wilkes, Belinda; Elvis, Martin

    1998-01-01

    The unified picture of X-ray/UV absorbers offers a unique opportunity to probe the nuclear environment of active galactic nuclei. To test the unified absorber scenario and to understand the physical properties of the absorber, we obtained the first UV spectrum of PG 1114+445 using the Hubble Space Telescope (HST) Faint Object Spectrograph. PG 1114+445 is known to have an X-ray ionized ('warm') absorber,so that UV absorption is predicted. The HST spectrum clearly shows strong UV absorption lines due to Lyalpha, C iv, and N v, blueshifted by approximately 530 km s(exp -1) with respect to the quasar redshift. Since both X-ray and UV absorbers are rare in radio-quiet quasars, these observations argue strongly that the X-ray and UV absorbers are closely physically related. perhaps identical. We place constraints on the parameters of the absorber and conclude that the mass outflow rate is comparable to the accretion rate in PG 1114+445.

  16. Measurement of nonuniform temperature and concentration distributions by combining line-of-sight tunable diode laser absorption spectroscopy with regularization methods.

    PubMed

    Liu, Chang; Xu, Lijun; Cao, Zhang

    2013-07-10

    Regularization methods were combined with line-of-sight tunable diode laser absorption spectroscopy (TDLAS) to measure nonuniform temperature and concentration distributions along the laser path when a priori information of the temperature distribution tendency is available. Relying on measurements of 12 absorption transitions of water vapor from 1300 to 1350 nm, the nonuniform temperature and concentration distributions were retrieved by making the use of nonlinear and linear regularization methods, respectively. To examine the effectiveness of regularization methods, a simulated annealing algorithm for nonlinear regularization was implemented to reconstruct the temperature distribution, while three linear regularization methods, namely truncated singular value decomposition, Tikhonov regularization, and a revised Tikhonov regularization method, were implemented to retrieve the concentration distribution. The results show that regularization methods not only can be used to retrieve temperature and concentration distributions closer to the original but also are less sensitive to measurement noise. When no sufficient optical access is available for TDLAS tomography, the methods proposed in the paper can be used to obtain more details of the combustion field with higher accuracy and robustness, which are expected to play a more important role in combustion diagnosis.

  17. Application of multiwall carbon nanotubes impregnated with 5-dodecylsalicylaldoxime for on-line copper preconcentration and determination in water samples by flame atomic absorption spectrometry.

    PubMed

    Tobiasz, Anna; Walas, Stanisław; Soto Hernández, Arlene; Mrowiec, Halina

    2012-07-15

    The paper presents application of multiwall carbon nanotubes (MWCNTs) modified with 5-dodecylsalicylaldoxime to copper(II) flow-injection on-line preconcentration and flame atomic absorption spectrometric (FAAS) determination. Two new sorbents were obtained by impregnation of MWCNTs with Cu(II)-LIX 622(®) complex, however in the first case modification was preceded by carbon wall activation via oxidization (Cu-LIX-CNT-A sorbent), and in the second one no surface activation was performed (Cu-LIX-CNT sorbent). It was found that effective leaching of initially introduced copper and Cu(II) retained in preconcentration process could be realized with the use 7% and 5% (v/v) nitric acid, for particular sorbents. Testing the influence of loading solution pH and rate of loading on sorption it was found out that optimal range of loading solution pH was about 4.5-6.3 for activated and 6.15-6.25 for non-activated CNT. Investigation of sorption kinetics showed that the process can be described by pseudo-second order reaction model. Sorption equilibrium conditions (90% sorption) for LIX-CNT-A and LIX-CNT were obtained after 8-15min, respectively and maximum sorption capacity for the new sorbents amounted to 18.1mgg(-1) and 31.6mgg(-1), respectively. For the examined sorbents enrichment factors increased with extension of loading time up to 180s: linearly for activated and non-linearly for non-activated MWCNTs. Influence of potential interferents such as Cd(II), Zn(II), Fe(III), Mg(II) and Ca(II) ions on copper(II) sorption on the new CNT materials was examined individually and with the use of 2(5-2) factorial design. The study revealed significant interference from iron, magnesium and calcium ions at relatively high concentrations. Applicability of the proposed sorbents was tested for Cu(II) determination in various kinds of water samples and the results were compared with those obtained with the use of ICP MS as a reference technique. Copper(II) determination in two certified

  18. FDTD/TDSE study of surface-enhanced infrared absorption by metal nanoparticles.

    SciTech Connect

    Chang, S.-H.; Schatz, G. C.; Gray, S. K.; Chemistry; Northwestern Univ.; National Cheng-Kung Univ.

    2006-01-01

    We study surface-enhanced infrared absorption, including multiphoton processes, due to the excitation of surface plasmons on metal nanoparticles. The time-dependent Schroedinger equation and finite-difference time-domain method are self-consistently coupled to treat the problem.

  19. Continuum absorption spectra in the far wings of the Hg 1S0-->3P1 resonance line broadened by Ar

    NASA Astrophysics Data System (ADS)

    Sato, Y.; Nakamura, T.; Okunishi, M.; Ohmori, K.; Chiba, H.; Ueda, K.

    1996-02-01

    Absolute reduced absorption coefficients for the Hg resonance line at 253.7 nm broadened by Ar were determined between 390 and 430 K in the spectral range from 20 to 1000 cm-1 on the red wing and from 20 to 400 cm-1 on the blue wing. The resultant reduced absorption coefficients are in fair agreement with those obtained by Petzold and Behmenburg [Z. Naturtorsch. Teil A 33, 1461 (1978)]. The observed A 30+<--X 10+ spectrum in the spectral range from 80 to 800 cm-1 on the red wing agrees remarkably well both in shape and magnitude with the quasistatic line shape calculated using the potential-energy curves of the HgAr van der Waals molecule given by Fuke, Saito, and Kaya [J. Chem. Phys. 81, 2591 (1984)], and Yamanouchi et al. [J. Chem. Phys. 88, 205 (1988)]. The blue-wing spectrum is interpreted as the B 31<--X 10+ free-free transition of HgAr by a simulation of the spectrum using uniform semiclassical treatment for the free-free Franck-Condon factor. The source of the satellites on the blue wing is attributed to the phase-interference effect arising from a stationary phase-shift difference between the B- and X-state translational wave functions. The stationary phase-shift difference arises owing to the existence of a maximum in the difference potential between the B and X states. The repulsive branches of the potential-energy curves of HgAr for the X and B states have been revised to give excellent agreement between the observed and calculated spectra, both in shape and magnitude.

  20. Investigation of Transmission Line Models for Switching Overvoltages Studies

    NASA Astrophysics Data System (ADS)

    Sadeghkhani, Iman; Ketabi, Abbas; Feuillet, Rene

    2013-06-01

    Overvoltages caused by switching operation of power system equipments might damage some equipment and delay power system restoration. This paper presents a comparison between transmission line (TL) models for overvoltages study and investigates which TL model is most proper for every case study. Both simulation time and accuracy factors of TL models are considered for selecting best TL model. Various cases of switching of transformer, shunt reactor, capacitor bank, and transmission line are investigated and simulation results for a partial of 39-bus New England test system, show that the proposed TL model evaluation increase accuracy and reduce simulation time (accelerate power system restoration) properly.

  1. Calculated Hanle transmission and absorption spectra of the {sup 87}Rb D{sub 1} line with residual magnetic field for arbitrarily polarized light

    SciTech Connect

    Noh, Heung-Ryoul; Moon, Han Seb

    2010-09-15

    This paper reports a theoretical study on the transmission spectra of an arbitrarily polarized laser beam through a rubidium cell with or without a buffer gas in Hanle-type coherent population trapping (CPT). This study examined how laser polarization, transverse magnetic field, and collisions with buffer gas affects the spectrum. The transmission spectrum due to CPT and the absorption spectrum due to the level crossing absorption (LCA) were calculated according to the laser polarization. The results show that the LCA is strongly dependent on the transverse magnetic field and interaction time of the atoms with a laser light via collisions with the buffer gas. In addition, the spectral shape of the calculated Hanle spectrum is closely related to the direction between the (stray) transverse magnetic field and polarization of the laser.

  2. Microwave Resonator Measurements of Atmospheric Absorption Coefficients: A Preliminary Design Study

    NASA Technical Reports Server (NTRS)

    Walter, Steven J.; Spilker, Thomas R.

    1995-01-01

    A preliminary design study examined the feasibility of using microwave resonator measurements to improve the accuracy of atmospheric absorption coefficients and refractivity between 18 and 35 GHz. Increased accuracies would improve the capability of water vapor radiometers to correct for radio signal delays caused by Earth's atmosphere. Calibration of delays incurred by radio signals traversing the atmosphere has applications to both deep space tracking and planetary radio science experiments. Currently, the Cassini gravity wave search requires 0.8-1.0% absorption coefficient accuracy. This study examined current atmospheric absorption models and estimated that current model accuracy ranges from 5% to 7%. The refractivity of water vapor is known to 1% accuracy, while the refractivity of many dry gases (oxygen, nitrogen, etc.) are known to better than 0.1%. Improvements to the current generation of models will require that both the functional form and absolute absorption of the water vapor spectrum be calibrated and validated. Several laboratory techniques for measuring atmospheric absorption and refractivity were investigated, including absorption cells, single and multimode rectangular cavity resonators, and Fabry-Perot resonators. Semi-confocal Fabry-Perot resonators were shown to provide the most cost-effective and accurate method of measuring atmospheric gas refractivity. The need for accurate environmental measurement and control was also addressed. A preliminary design for the environmental control and measurement system was developed to aid in identifying significant design issues. The analysis indicated that overall measurement accuracy will be limited by measurement errors and imprecise control of the gas sample's thermodynamic state, thermal expansion and vibration- induced deformation of the resonator structure, and electronic measurement error. The central problem is to identify systematic errors because random errors can be reduced by averaging

  3. Photodissociation of thioglycolic acid studied by femtosecond time-resolved transient absorption spectroscopy

    SciTech Connect

    Attar, Andrew R.; Blumling, Daniel E.; Knappenberger, Kenneth L. Jr.

    2011-01-14

    Steady-state and time-resolved spectroscopies were employed to study the photodissociation of both the neutral (HS-CH{sub 2}-COOH) and doubly deprotonated ({sup -}S-CH{sub 2}-COO{sup -}) forms of thioglycolic acid (TGA), a common surface-passivating ligand used in the aqueous synthesis and organization of semiconducting nanostructures. Room temperature UV-Vis absorption spectroscopy indicated strong absorption by the S{sub 1} and S{sub 2} excited states at 250 nm and 185 nm, respectively. The spectrum also contained a weaker absorption band that extended to approximately 550 nm, which was assigned to the {pi}{sub CO}{sup *}(leftarrow)n{sub O} transition. Femtosecond time-resolved transient absorption spectroscopy was performed on TGA using 400 nm excitation and a white-light continuum probe to provide the temporally and spectrally resolved data. Both forms of TGA underwent a photoinduced dissociation from the excited state to form an {alpha}-thiol-substituted acyl radical ({alpha}-TAR, S-CH{sub 2}-CO). For the acidic form of TGA, radical formation occurred with an apparent time constant of 60 {+-} 5 fs; subsequent unimolecular decay took 400 {+-} 60 fs. Similar kinetics were observed for the deprotonated form of TGA (70 {+-} 10 fs radical formation; 420 {+-} 40 fs decay). The production of the {alpha}-TAR was corroborated by the observation of its characteristic optical absorption. Time-resolved data indicated that the photoinduced dissociation of TGA via cleavage of the C-OH bond occurred rapidly ({<=}100 fs). The prevalence of TGA in aqueous semiconducting nanoparticles makes its absorption in the visible spectral region and subsequent dissociation key to understanding the behavior of nanoscale systems.

  4. A Population of Faint Extended Line Emitters and the Host Galaxies of Optically Thick QSO Absorption Systems

    NASA Astrophysics Data System (ADS)

    Rauch, Michael; Haehnelt, Martin; Bunker, Andrew; Becker, George; Marleau, Francine; Graham, James; Cristiani, Stefano; Jarvis, Matt; Lacey, Cedric; Morris, Simon; Peroux, Celine; Röttgering, Huub; Theuns, Tom

    2008-07-01

    We have conducted a long-slit search for low surface brightness Lyα emitters at redshift 2.67 < z < 3.75. A 92 hr long exposure with the ESO VLT FORS2 instrument down to a 1 σ surface brightness detection limit of 8 × 10-20 erg cm-2 s-1 arcsec-2 per arcsec2 aperture yielded a sample of 27 single line emitters with fluxes of a few × 10-18 erg s-1 cm-2. We present arguments that most objects are indeed Lyα. The large comoving number density, 3 × 10-2 h370 Mpc-3, the large covering factor, dN/dz ~ 0.2-1, and the often extended Lyα emission suggest that the emitters can be identified with the elusive host population of damped Lyα systems (DLAS) and high column density Lyman limit systems (LLS). A small inferred star formation rate, perhaps supplemented by cooling radiation, appears to energetically dominate the Lyα emission, and is consistent with the low metallicity, low dust content, and theoretically inferred low masses of DLAS, and with the relative lack of success of earlier searches for their optical counterparts. Some of the line profiles show evidence for radiative transfer in galactic outflows. Stacking surface brightness profiles, we find emission out to at least 4''. The centrally concentrated emission of most objects appears to light up the outskirts of the emitters (where LLS arise) down to a column density where the conversion from UV to Lyα photon becomes inefficient. DLAS, high column density LLS, and the emitter population discovered in this survey appear to be different observational manifestations of the same low-mass, protogalactic building blocks of present-day L* galaxies. Based partly on observations made with ESO Telescopes at the Paranal Observatories under Program ID LP173.A-0440, and partly 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

  5. Compartmental absorption modeling and site of absorption studies to determine feasibility of an extended-release formulation of an HIV-1 attachment inhibitor phosphate ester prodrug.

    PubMed

    Brown, Jonathan; Chien, Caly; Timmins, Peter; Dennis, Andrew; Doll, Walter; Sandefer, Erik; Page, Richard; Nettles, Richard E; Zhu, Li; Grasela, Dennis

    2013-06-01

    BMS-663068 is a phosphonooxymethyl ester prodrug under development for the treatment of HIV/AIDS. The prodrug is designed to overcome the solubility-limited bioavailability of the active moiety, BMS-626529. BMS-663068 is not absorbed from the gastrointestinal (GI) tract and requires enzymatic conversion by alkaline phosphatase to BMS-626529 immediately before absorption. In the light of the known short in vivo half-life of BMS-626529, compartmental absorption modeling was used to predict the potential feasibility of extended-release (ER) delivery to achieve target Cmax :Cmin ratios. To further refine the model with respect to colonic absorption, the regional absorption of BMS-626529 following delivery of BMS-663068 to upper and lower GI sites was characterized through a site of absorption study in human subjects. A refined model was subsequently applied to guide the development of ER tablet formulations. Comparisons of results from the refined model to the in vivo human pharmacokinetic data for three selected ER formulations demonstrate the utility of the model in predicting feasibility of ER delivery and in directing formulation development.

  6. Dithizone immobilized silica gel on-line preconcentration of trace copper with detection by flame atomic absorption spectrometry.

    PubMed

    Yu, Hong-Mei; Song, Hua; Chen, Ming-Li

    2011-07-15

    A novel adsorbent-silica gel bound dithizone (H(2)Dz-SG) was prepared and used as solid-phase extraction of copper from complex matrix. The H(2)Dz-SG is investigated by means of FT-IR spectra and the SEM images, demonstrating the bonding of dithizone. The H(2)Dz-SG quantitatively adsorb copper ions, and the retained copper is afterwards collected by elution of 10% (v/v) nitric acid. An on-line flow injection solid-phase extraction procedure was developed for trace copper separation and preconcentration with detection by flame atomic spectrometry. By loading 5.4 mL of sample solution, a liner range of 0.5-120 μg L(-1), an enrichment factor of 42.6, a detection limit of 0.2 μg L(-1) and a precision of 1.7% RSD at the 40 μg L(-1) level (n=11) were obtained, along with a sampling frequency of 47 h(-1). The dynamic sorption capacity of H(2)Dz-SG to Cu(2+) was 0.76 mg g(-1). The accuracy of the proposed procedure was evaluated by determination of copper in reference water sample. The potential applications of the procedure for extraction of trace copper were successfully accomplished in water samples (tap, rain, snow, sea and river). The spiking recoveries within 91-107% are achieved. PMID:21645750

  7. A Stringent Limit on Variation of the Fine-Structure Constant Using Absorption Line Multiplets in the Early Universe

    NASA Astrophysics Data System (ADS)

    Le, T. D.

    2016-06-01

    One of the key questions of modern physics concerns the possibility that physical constants have varied throughout the history of the Universe. The standard model of physics is built on these constants, but it does not provide any explanation for their values, nor does it require their constancy over space and time. Here, we set a new limit on possible spatial and temporal variations of the fine-structure constant α = e 2/4πɛ0 ħc by comparing transitions and line multiplets in an ensemble of Fe II λ 1608, λ 2344, λ 2374, λ 2383, λ 2587, and λ 2600 observed in the early Universe with those measured in the laboratory. Based on the optical spectrum observations of QSO HE 0515-4414, we deduce a constraint of Δα/α = (-0.157± 0.300)×10-6 at redshift z = 1.15. At present, this represents the tightest limit on Δα/α in early cosmological epochs compared to the published results in the literature.

  8. Dithizone immobilized silica gel on-line preconcentration of trace copper with detection by flame atomic absorption spectrometry.

    PubMed

    Yu, Hong-Mei; Song, Hua; Chen, Ming-Li

    2011-07-15

    A novel adsorbent-silica gel bound dithizone (H(2)Dz-SG) was prepared and used as solid-phase extraction of copper from complex matrix. The H(2)Dz-SG is investigated by means of FT-IR spectra and the SEM images, demonstrating the bonding of dithizone. The H(2)Dz-SG quantitatively adsorb copper ions, and the retained copper is afterwards collected by elution of 10% (v/v) nitric acid. An on-line flow injection solid-phase extraction procedure was developed for trace copper separation and preconcentration with detection by flame atomic spectrometry. By loading 5.4 mL of sample solution, a liner range of 0.5-120 μg L(-1), an enrichment factor of 42.6, a detection limit of 0.2 μg L(-1) and a precision of 1.7% RSD at the 40 μg L(-1) level (n=11) were obtained, along with a sampling frequency of 47 h(-1). The dynamic sorption capacity of H(2)Dz-SG to Cu(2+) was 0.76 mg g(-1). The accuracy of the proposed procedure was evaluated by determination of copper in reference water sample. The potential applications of the procedure for extraction of trace copper were successfully accomplished in water samples (tap, rain, snow, sea and river). The spiking recoveries within 91-107% are achieved.

  9. The Redshifted Hydrogen Balmer and Metastable He 1 Absorption Line System in Mini-FeLoBAL Quasar SDSS J112526.12+002901.3: A Parsec-scale Accretion Inflow?

    NASA Astrophysics Data System (ADS)

    Shi, Xi-Heng; Jiang, Peng; Wang, Hui-Yuan; Zhang, Shao-Hua; Ji, Tuo; Liu, Wen-Juan; Zhou, Hong-Yan

    2016-10-01

    The accretion of the interstellar medium onto central super-massive black holes is widely accepted as the source of the gigantic energy released by the active galactic nuclei. However, few pieces of observational evidence have been confirmed directly demonstrating the existence of the inflows. The absorption line system in the spectra of quasar SDSS J112526.12+002901.3 presents an interesting example in which the rarely detected hydrogen Balmer and metastable He i absorption lines are found redshifted to the quasar's rest frame along with the low-ionization metal absorption lines Mg ii, Fe ii, etc. The repeated SDSS spectroscopic observations suggest a transverse velocity smaller than the radial velocity. The motion of the absorbing medium is thus dominated by infall. The He i* lines present a powerful probe to the strength of ionizing flux, while the Balmer lines imply a dense environment. With the help of photoionization simulations, we find that the absorbing medium is exposed to the radiation with ionization parameter U ≈ 10-1.8, and the density is n({{H}})≈ {10}9 {{cm}}-3. Thus the absorbing medium is located ˜4 pc away from the central engine. According to the similarity in the distance and physical conditions between the absorbing medium and the torus, we strongly propose the absorption line system as a candidate for the accretion inflow, which originates in the inner surface of the torus.

  10. A New On-Line Resource for Psycholinguistic Studies

    ERIC Educational Resources Information Center

    Szekely, Anna; Jacobsen, Thomas; D'Amico, Simona; Devescovi, Antonella; Andonoa, Elena; Herron, Daniel; Lu, Ching Ching; Pechmann, Thomas; Pleh, Csaba; Wicha, Nicole; Federmeier, Kara; Gerdjikova, Irina; Gutierrez, Gabriel; Hung, Daisy, Hsu, Jeanne; Iyer, Gowri; Kohnert, Kathryn; Mehotcheva, Teodora; Orozco-Figueroa, Araceli; Tzeng, Angela; Tzeng, Ovid; Arevalo, Analia; Vargha, Andras; Butler, Andrew C.; Buffington, Robert; Bates, Elizabeth

    2004-01-01

    Picture naming is a widely used technique in psycholinguistic studies. Here, we describe new on-line resources that our project has compiled and made available to researchers on the world wide web at http://crl.ucsd.edu/~aszekely/ipnp/. The website provides access to a wide range of picture stimuli and related norms in seven languages. Picture…

  11. What Does a Random Line Look Like: An Experimental Study

    ERIC Educational Resources Information Center

    Turner, Nigel E.; Liu, Eleanor; Toneatto, Tony

    2011-01-01

    The study examined the perception of random lines by people with gambling problems compared to people without gambling problems. The sample consisted of 67 probable pathological gamblers and 46 people without gambling problems. Participants completed a number of questionnaires about their gambling and were then presented with a series of random…

  12. Determination of lead in sea-water with a graphite furnace atomic absorption spectrometer and an improved automatic on-line pre-concentration system

    NASA Astrophysics Data System (ADS)

    Liu, Zhen-Shan; Huang, Shang-Da

    1995-03-01

    An improved automatic on-line pre-concentration system for graphite furnace atomic absorption spectrometry (GFAAS) for the determination of trace metals in sea-water was developed. This system was modified from a Perkin-Elmer AS-40 autosampler by mounting a silica gel C 18 microcolumn near the tip of the autosampler capillary. The pre-concentration procedure was performed by using a four-way distribution valve and controlled by a programmable controller. The pre-concentration system developed previously was improved by using a peristaltic pump to replace the reciprocating pumps, a newly designed tube bed adjuster to release the back-pressure in the pre-concentration system, and a better control program, such that on-line pre-concentration became more reliable and fully automatic. The chelating agent ammonium pyrolidinedithiocarbamate (APDC) and a miniature column packed with 5 mg of C 18 silica gel were used for pre-concentration. This system was tested by analyzing the lead content in reference standard sea-water samples. A sample volume of only 2 ml was required to determine lead in sea-water. The relative limit of detection of lead was 3.5 pg/ml.

  13. An automated flow injection system for metal determination by flame atomic absorption spectrometry involving on-line fabric disk sorptive extraction technique.

    PubMed

    Anthemidis, A; Kazantzi, V; Samanidou, V; Kabir, A; Furton, K G

    2016-08-15

    A novel flow injection-fabric disk sorptive extraction (FI-FDSE) system was developed for automated determination of trace metals. The platform was based on a minicolumn packed with sol-gel coated fabric media in the form of disks, incorporated into an on-line solid-phase extraction system, coupled with flame atomic absorption spectrometry (FAAS). This configuration provides minor backpressure, resulting in high loading flow rates and shorter analytical cycles. The potentials of this technique were demonstrated for trace lead and cadmium determination in environmental water samples. The applicability of different sol-gel coated FPSE media was investigated. The on-line formed complex of metal with ammonium pyrrolidine dithiocarbamate (APDC) was retained onto the fabric surface and methyl isobutyl ketone (MIBK) was used to elute the analytes prior to atomization. For 90s preconcentration time, enrichment factors of 140 and 38 and detection limits (3σ) of 1.8 and 0.4μgL(-1) were achieved for lead and cadmium determination, respectively, with a sampling frequency of 30h(-1). The accuracy of the proposed method was estimated by analyzing standard reference materials and spiked water samples. PMID:27260436

  14. Study of the cavity-magnon-polariton transmission line shape

    NASA Astrophysics Data System (ADS)

    Harder, Michael; Bai, LiHui; Match, Christophe; Sirker, Jesko; Hu, CanMing

    2016-11-01

    We experimentally and theoretically investigate the microwave transmission line shape of the cavity-magnon-polariton (CMP) created by inserting a low damping magnetic insulator into a high quality 3D microwave cavity. While fixed field measurements are found to have the expected Lorentzian characteristic, at fixed frequencies the field swept line shape is in general asymmetric. Such fixed frequency measurements demonstrate that microwave transmission can be used to access magnetic characteristics of the CMP, such as the field line width Δ H. By developing an effective oscillator model of the microwave transmission we show that these line shape features are general characteristics of harmonic coupling. At the same time, at the classical level the underlying physical mechanism of the CMP is electrodynamic phase correlation and a second model based on this principle also accurately reproduces the experimental line shape features. In order to understand the microscopic origin of the effective coupled oscillator model and to allow for future studies of CMP phenomena to extend into the quantum regime, we develop a third, microscopic description, based on a Green's function formalism. Using this method we calculate the transmission spectra and find good agreement with the experimental results.

  15. Study of the Auger line shape of polyethylene and diamond

    NASA Technical Reports Server (NTRS)

    Dayan, M.; Pepper, S. V.

    1984-01-01

    The KVV Auger electron line shapes of carbon in polyethylene and diamond have been studied. The spectra were obtained in derivative form by electron beam excitation. They were treated by background subtraction, integration and deconvolution to produce the intrinsic Auger line shape. Electron energy loss spectra provided the response function in the deconvolution procedure. The line shape from polyethylene is compared with spectra from linear alkanes and with a previous spectrum of Kelber et al. Both spectra are compared with the self-convolution of their full valence band densities of states and of their p-projected densities. The experimental spectra could not be understood in terms of existing theories. This is so even when correlation effects are qualitatively taken into account account to the theories of Cini and Sawatzky and Lenselink.

  16. Kinetic study of carbon dioxide absorption into glycine promoted diethanolamine (DEA)

    NASA Astrophysics Data System (ADS)

    Pudjiastuti, Lily; Susianto, Altway, Ali; IC, Maria Hestia; Arsi, Kartika

    2015-12-01

    In industry, especially petrochemical, oil and natural gas industry, required separation process of CO2 gas which is a corrosive gas (acid gas). This characteristic can damage the plant utility and piping systems as well as reducing the caloric value of natural gas. Corrosive characteristic of CO2 will appear in areas where there is a decrease in temperature and pressure, such as at the elbow pipe, tubing, cooler and injector turbine. From disadvantages as described above, then it is important to do separation process in the CO2 gas stream, one of the method for remove CO2 from the gas stream is reactive absorption using alkanolamine based solution with promotor. Therefore, this study is done to determine the kinetics constant of CO2 absorption in diethanolamine (DEA) solution using a glycine promoter. Glycine is chosen as a promoter because glycine is a primary amine compound which is reactive, moreover, glycine has resistance to high temperatures so it will not easy to degradable and suitable for application in industry. The method used in this study is absorption using laboratory scale wetted wall column equipment at atmospheric of pressure. This study will to provide the reaction kinetics data information in order to optimize the separation process of CO2 in the industrialized world. The experimental results show that rising temperatures from 303,15 - 328,15 K and the increase of concentration of glycine from 1% - 3% weight will increase the absorption rate of carbon dioxide in DEA promoted with glycine by 24,2% and 59,764% respectively, also the reaction kinetic constant is 1.419 × 1012 exp (-3634/T) (m3/kmol.s). This result show that the addition of glycine as a promoter can increase absorption rate of carbon dioxide in diethanolamine solution and cover the weaknesses of diethanolamine solution.

  17. Studies on mass energy-absorption coefficients and effective atomic energy-absorption cross sections for carbohydrates

    NASA Astrophysics Data System (ADS)

    Ladhaf, Bibifatima M.; Pawar, Pravina P.

    2015-04-01

    We measured here the mass attenuation coefficients (μ/ρ) of carbohydrates, Esculine (C15H16O9), Sucrose (C12H22O11), Sorbitol (C6H14O6), D-Galactose (C6H12O6), Inositol (C6H12O6), D-Xylose (C5H10O5) covering the energy range from 122 keV up to 1330 keV photon energies by using gamma ray transmission method in a narrow beam good geometry set-up. The gamma-rays were detected using NaI(Tl) scintillation detection system with a resolution of 8.2% at 662 keV. The attenuation coefficient data were then used to obtain the total attenuation cross-section (σtot), molar extinction coefficients (ε), mass-energy absorption coefficients (μen/ρ) and effective (average) atomic energy-absorption cross section (σa,en) of the compounds. These values are found to be in good agreement with the theoretical values calculated based on XCOM data.

  18. Application of Doehlert designs for optimisation of an on-line preconcentration system for copper determination by flame atomic absorption spectrometry.

    PubMed

    Ferreira, Sérgio L C; Bezerra, Marcos A; Dos Santos, Walter N L; Neto, Benı X0301 Cio B

    2003-11-01

    In the present paper, a system for on-line preconcentration and determination of copper by flame atomic absorption spectrometry (FAAS) was developed. It was based on solid phase extraction of copper(II) ions on a minicolumn of Amberlite XAD-2 loaded with 2-(2-thiazolylazo)-5-dimethylaminophenol (TAM). The optimisation process was carried out using Doehlert designs. Four variables (sampling flow rate, SR; elution flow rate, buffer concentration, BC; and pH) were regarded as factors in the optimisation. The parameter "sensitivity efficiency (SE)" proposed in this paper, and defined as the analytical signal obtained for an on-line enrichment system for a preconcentration time of 1 min was used as analytical response in the optimisation process. Using the established experimental conditions, the proposed on-line system allowed determination of copper with detection limit (3sigma/S) of 0.23 mug l(-1), and a precision (repeatability), calculated as relative standard deviation (R.S.D.) of 3.9 and 3.7% for copper concentration of 5.00 and 20.00 mug l(-1), respectively. The preconcentration factor obtained is 62. The recovery achieved for copper determination in presence of several cations demonstrated that this has enough selectivity for analysis of food samples. The robustness of the proposed system was also evaluated. The accuracy was confirmed by analysis of the following certified reference materials (CRMs): Rice flour NIES 10a, Spinach leaves NIST 1570a, Apples leaves NIST 1515 and Orchard leaves NBS 1571. This procedure was applied for copper determination in natural food samples. PMID:18969189

  19. On the possibilities of high-resolution continuum source graphite furnace atomic absorption spectrometry for the simultaneous or sequential monitoring of multiple atomic lines

    NASA Astrophysics Data System (ADS)

    Resano, M.; Rello, L.; Flórez, M.; Belarra, M. A.

    2011-05-01

    This paper explores the potential of commercially available high-resolution continuum source graphite furnace atomic absorption spectrometry instrumentation for the simultaneous or sequential monitoring of various atomic lines, in an attempt to highlight the analytical advantages that can be derived from this strategy. In particular, it is demonstrated how i) the monitoring of multiplets may allow for the simple expansion of the linear range, as shown for the measurement of Ni using the triplet located in the vicinity of 234.6 nm; ii) the use of a suitable internal standard may permit improving the precision and help in correcting for matrix-effects, as proved for the monitoring of Ni in different biological samples; iii) direct and multi-element analysis of solid samples may be feasible on some occasions, either by monitoring various atomic lines that are sufficiently close (truly simultaneous monitoring, as demonstrated in the determination of Co, Fe and Ni in NIST 1566a Oyster tissue) or, alternatively, by opting for a selective and sequential atomization of the elements of interest during every single replicate. Determination of Cd and Ni in BCR 679 White cabbage is attempted using both approaches, which permits confirming that both methods can offer very similar and satisfactory results. However, it is important to stress that the second approach provides more flexibility, since analysis is no longer limited to those elements that show very close atomic lines (closer than 0.3 nm in the ultraviolet region) with a sensitivity ratio similar to the concentration ratio of the analytes in the samples investigated.

  20. X-ray absorption spectral studies of copper (II) mixed ligand complexes

    NASA Astrophysics Data System (ADS)

    Soni, B.; Dar, Davood Ah; Shrivastava, B. D.; Prasad, J.; Srivastava, K.

    2014-09-01

    X-ray absorption spectra at the K-edge of copper have been studied in two copper mixed ligand complexes, one having tetramethyethylenediamine (tmen) and the other having tetraethyethylenediamine (teen) as one of the ligands. The spectra have been recorded at BL-8 dispersive extended X-ray absorption fine structure (EXAFS) beamline at the 2.5 GeV INDUS- 2 synchrotron, RRCAT, Indore, India. The data obtained has been processed using the data analysis program Athena. The energy of the K-absorption edge, chemical shift, edge-width and shift of the principal absorption maximum in the complexes have been determined and discussed. The values of these parameters have been found to be approximately the same in both the complexes indicating that the two complexes possess similar chemical environment around the copper metal atom. The chemical shift has been utilized to estimate effective nuclear charge on the absorbing atom. The normalized EXAFS spectra have been Fourier transformed. The position of the first peak in the Fourier transform gives the value of first shell bond length, which is shorter than the actual bond length because of energy dependence of the phase factors in the sine function of the EXAFS equation. This distance is thus the phase- uncorrected bond length. Bond length has also been determined by Levy's, Lytle's and Lytle, Sayers and Stern's (LSS) methods. The results obtained from LSS and the Fourier transformation methods are comparable with each other, since both are phase uncorrected bond lengths.

  1. An x-ray absorption spectroscopy study of Mo oxidation in Pb at elevated temperatures

    SciTech Connect

    Liu, Shanshan; Olive, Daniel; Terry, Jeff; Segre, Carlo U.

    2009-06-30

    The corrosion of fuel cladding and structural materials by lead and lead-bismuth eutectic in the liquid state at elevated temperatures is an issue that must be considered when designing advanced nuclear systems and high-power spallation neutron targets. In this work, lead corrosion studies of molybdenum were performed to investigate the interaction layer as a function of temperature by X-ray absorption spectroscopy. In situ X-ray absorption measurements on a Mo substrate with a 3-6 {micro}m layer of Pb deposited by thermal evaporation were performed at temperatures up to 900 C and at a 15{sup o} angle to the incident X-rays. The changes in the local atomic structure of the corrosion layer are visible in the difference extended X-ray absorption fine structure and the linear combination fitting of the X-ray absorption near-edge structure to as-deposited molybdenum sample and molybdenum oxide (MoO{sub 2} and MoO{sub 3}) standards. The data are consistent with the appearance of MoO{sub 3} in an intermediate temperature range (650-800 C) and the more stable MoO{sub 2} phase dominating at high and low temperatures.

  2. Enhancement of conduction noise absorption by hybrid absorbers composed of indium-tin-oxide thin film and magnetic composite sheet on a microstrip line

    SciTech Connect

    Kim, Sun-Hong; Kim, Sung-Soo

    2014-05-05

    In order to develop wide-band noise absorbers with a focused design for low frequency performance, this study investigates hybrid absorbers that are composed of conductive indium-tin-oxide (ITO) thin film and magnetic composite sheets. The ITO films prepared via reactive sputtering exhibit a typical value of electrical resistivity of ≃10{sup −4} Ω m. Rubber composites with flaky Fe-Si-Al particles are used as the magnetic sheet with a high permeability and high permittivity. For the ITO film with a low surface resistance and covered by the magnetic sheet, approximately 90% power absorption can be obtained at 1 GHz, which is significantly higher than that of the original magnetic sheet or ITO film. The high power absorption of the hybrid absorber is attributed to the enhanced ohmic loss of the ITO film through increased electric field strength bounded by the upper magnetic composite sheet. However, for the reverse layering sequence of the ITO film, the electric field experienced by ITO film is very weak due to the electromagnetic shielding by the under layer of magnetic sheet, which does not result in enhanced power absorption.

  3. Empowering line intensity mapping to study early galaxies

    NASA Astrophysics Data System (ADS)

    Comaschi, P.; Ferrara, A.

    2016-09-01

    Line intensity mapping is a superb tool to study the collective radiation from early galaxies. However, the method is hampered by the presence of strong foregrounds, mostly produced by low-redshift interloping lines. We present here a general method to overcome this problem which is robust against foreground residual noise and based on the cross-correlation function ψαL(r) between diffuse line emission and Lyα emitters (LAE). We compute the diffuse line (Lyα is used as an example) emission from galaxies in a (800Mpc)3 box at z = 5.7 and 6.6. We divide the box in slices and populate them with 14000(5500) LAEs at z = 5.7(6.6), considering duty cycles from 10-3 to 1. Both the LAE number density and slice volume are consistent with the expected outcome of the Subaru HSC survey. We add gaussian random noise with variance σN up to 100 times the variance of the Lyα emission, σα, to simulate residual foregrounds and compute ψαL(r). We find that the signal-to-noise of the observed ψαL(r) does not change significantly if σN ≤ 10σα and show that in these conditions the mean line intensity, ILyα, can be precisely recovered independently of the LAE duty cycle. Even if σN = 100σα, Iα can be constrained within a factor 2. The method works equally well for any other line (e.g. [CII], HeII) used for the intensity mapping experiment.

  4. A comparative study of intervening and associated H I 21-cm absorption profiles in redshifted galaxies

    NASA Astrophysics Data System (ADS)

    Curran, S. J.; Duchesne, S. W.; Divoli, A.; Allison, J. R.

    2016-08-01

    The star-forming reservoir in the distant Universe can be detected through H I 21-cm absorption arising from either cool gas associated with a radio source or from within a galaxy intervening the sight-line to the continuum source. In order to test whether the nature of the absorber can be predicted from the profile shape, we have compiled and analysed all of the known redshifted (z ≥ 0.1) H I 21-cm absorption profiles. Although between individual spectra there is too much variation to assign a typical spectral profile, we confirm that associated absorption profiles are, on average, wider than their intervening counterparts. It is widely hypothesised that this is due to high velocity nuclear gas feeding the central engine, absent in the more quiescent intervening absorbers. Modelling the column density distribution of the mean associated and intervening spectra, we confirm that the additional low optical depth, wide dispersion component, typical of associated absorbers, arises from gas within the inner parsec. With regard to the potential of predicting the absorber type in the absence of optical spectroscopy, we have implemented machine learning techniques to the 55 associated and 43 intervening spectra, with each of the tested models giving a ≳80% accuracy in the prediction of the absorber type. Given the impracticability of follow-up optical spectroscopy of the large number of 21-cm detections expected from the next generation of large radio telescopes, this could provide a powerful new technique with which to determine the nature of the absorbing galaxy.

  5. Correcting for Telluric Absorption: Methods, Case Studies, and Release of the TelFit Code

    NASA Astrophysics Data System (ADS)

    Gullikson, Kevin; Dodson-Robinson, Sarah; Kraus, Adam

    2014-09-01

    Ground-based astronomical spectra are contaminated by the Earth's atmosphere to varying degrees in all spectral regions. We present a Python code that can accurately fit a model to the telluric absorption spectrum present in astronomical data, with residuals of ~3%-5% of the continuum for moderately strong lines. We demonstrate the quality of the correction by fitting the telluric spectrum in a nearly featureless A0V star, HIP 20264, as well as to a series of dwarf M star spectra near the 819 nm sodium doublet. We directly compare the results to an empirical telluric correction of HIP 20264 and find that our model-fitting procedure is at least as good and sometimes more accurate. The telluric correction code, which we make freely available to the astronomical community, can be used as a replacement for telluric standard star observations for many purposes.

  6. Correcting for telluric absorption: Methods, case studies, and release of the TelFit code

    SciTech Connect

    Gullikson, Kevin; Kraus, Adam; Dodson-Robinson, Sarah

    2014-09-01

    Ground-based astronomical spectra are contaminated by the Earth's atmosphere to varying degrees in all spectral regions. We present a Python code that can accurately fit a model to the telluric absorption spectrum present in astronomical data, with residuals of ∼3%-5% of the continuum for moderately strong lines. We demonstrate the quality of the correction by fitting the telluric spectrum in a nearly featureless A0V star, HIP 20264, as well as to a series of dwarf M star spectra near the 819 nm sodium doublet. We directly compare the results to an empirical telluric correction of HIP 20264 and find that our model-fitting procedure is at least as good and sometimes more accurate. The telluric correction code, which we make freely available to the astronomical community, can be used as a replacement for telluric standard star observations for many purposes.

  7. The HI absorption "Zoo"

    NASA Astrophysics Data System (ADS)

    Geréb, K.; Maccagni, F. M.; Morganti, R.; Oosterloo, T. A.

    2015-03-01

    We present an analysis of the H I 21 cm absorption in a sample of 101 flux-selected radio AGN (S1.4 GHz> 50 mJy) observed with the Westerbork Synthesis Radio Telescope (WSRT). We detect H I absorption in 32 objects (30% of the sample). In a previous paper, we performed a spectral stacking analysis on the radio sources, while here we characterize the absorption spectra of the individual detections using the recently presented busy function. The H I absorption spectra show a broad variety of widths, shapes, and kinematical properties. The full width half maximum (FWHM) of the busy function fits of the detected H I lines lies in the range 32 km s-1absorption (FW20) lies in the range 63 km s-1lines (FWHM< 100 km s-1), intermediate widths (100 km s-1 200 km s-1). We study the kinematical and radio source properties of each group, with the goal of identifying different morphological structures of H I. Narrow lines mostly lie at the systemic velocity and are likely produced by regularly rotating H I disks or gas clouds. More H I disks can be present among galaxies with lines of intermediate widths; however, the H I in these sources is more unsettled. We study the asymmetry parameter and blueshift/redshift distribution of the lines as a function of their width. We find a trend for which narrow profiles are also symmetric, while broad lines are the most asymmetric. Among the broadest lines, more lines appear blueshifted than redshifted, similarly to what was found by previous studies. Interestingly, symmetric broad lines are absent from the sample. We argue that if a profile is broad, it is also asymmetric and shifted relative to the systemic velocity because it is tracing unsettled H I gas. In particular, besides three of the broadest (up to FW20 = 825 km s-1

  8. Trace level determination of cadmium in wine by on-line preconcentration in a 5-Br-PADAP functionalized wool-packed microcolumn coupled to flame atomic absorption spectrometry.

    PubMed

    Monasterio, Romina P; Wuilloud, Rodolfo G

    2009-10-15

    An on-line retention and preconcentration system based on a sheep wool-packed microcolumn combined with flame atomic absorption spectrometry is proposed for trace level determination of Cd in wine. A chelating reagent 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol was immobilized onto the wool before retention of the analyte. Several factors influencing the preconcentration efficiency of Cd and his subsequent determination, such as pH, eluent type, sample and eluent flow rates, interfering effects, were studied. A preconcentration factor of 39 was obtained with only 20 mL of sample. The relative standard deviation for five determinations of 1 microg L(-1) Cd was 3.4%. The calibration graph was linear with a correlation coefficient of 0.998 at levels near the detection limit and up to at least 25 microg L(-1). The limit of detection was 37 ng L(-1). The accuracy of the proposed methodology was tested by comparison of the results with those obtained by electrothermal atomic absorption spectrometry analysis along with a recovery study. Finally, the method was employed for evaluating Cd levels in different wines including, blank, rose, and red.

  9. Absorption-line detections of 10{sup 5}-10{sup 6} K gas in spiral-rich groups of galaxies

    SciTech Connect

    Stocke, John T.; Keeney, Brian A.; Danforth, Charles W.; Syphers, David; Yamamoto, H.; Shull, J. Michael; Green, James C.; Froning, Cynthia; Savage, Blair D.; Wakker, Bart; Kim, Tae-Sun; Ryan-Weber, Emma V.; Kacprzak, Glenn G.

    2014-08-20

    Using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope, the COS Science Team has conducted a high signal-to-noise survey of 14 bright QSOs. In a previous paper, these far-UV spectra were used to discover 14 'warm' (T ≥ 10{sup 5} K) absorbers using a combination of broad Lyα and broad O VI absorptions. A reanalysis of a few of this new class of absorbers using slightly relaxed fitting criteria finds as many as 20 warm absorbers could be present in this sample. A shallow, wide spectroscopic galaxy redshift survey has been conducted around these sight lines to investigate the warm absorber environment, which is found to be spiral-rich groups or cluster outskirts with radial velocity dispersions σ = 250-750 km s{sup –1}. While 2σ evidence is presented favoring the hypothesis that these absorptions are associated with the galaxy groups and not with the individual, nearest galaxies, this evidence has considerable systematic uncertainties and is based on a small sample size so it is not entirely conclusive. If the associations are with galaxy groups, the observed frequency of warm absorbers (dN/dz = 3.5-5 per unit redshift) requires them to be very extended as an ensemble on the sky (∼1 Mpc in radius at high covering factor). Most likely these warm absorbers are interface gas clouds whose presence implies the existence of a hotter (T ∼ 10{sup 6.5} K), diffuse, and probably very massive (>10{sup 11} M {sub ☉}) intra-group medium which has yet to be detected directly.

  10. Compressed shell conditions extracted from spectroscopic analysis of Ti K-shell absorption spectra with evaluation of line self-emission

    NASA Astrophysics Data System (ADS)

    Johns, H. M.; Mancini, R. C.; Hakel, P.; Nagayama, T.; Smalyuk, V. A.; Regan, S. P.; Delettrez, J.

    2014-08-01

    Ti-doped tracer layers embedded in the shell at varying distances from the fuel-shell interface serve as a spectroscopic diagnostic for direct-drive experiments conducted at OMEGA. Detailed modeling of Ti K-shell absorption spectra produced in the tracer layer considers n = 1-2 transitions in F- through Li-like Ti ions in the 4400-4800 eV range, both including and excluding line self-emission. Testing the model on synthetic spectra generated from 1-D LILAC hydrodynamic simulations reveals that the model including self-emission best reproduces the simulation, while the model excluding self-emission overestimates electron temperature Te and density Ne to a higher degree for layers closer to the core. The prediction of the simulation that the magnitude of Te and duration of Ti absorption will be strongly tied to the distance of the layer from the core is consistent with the idea that regions of the shell close to the core are more significantly heated by thermal transport out of the hot dense core, but more distant regions are less affected by it. The simulation predicts more time variation in the observed Te, Ne conditions in the compressed shell than is observed in the experiment, analysis of which reveals conditions remain in the range Te = 400-600 eV and Ne = 3.0-10.0 × 1024 cm-3 for all but the most distant Ti-doped layer, with error bars ˜5% Te value and ˜10% Ne on average. The Te, Ne conditions of the simulation lead to a greater degree of ionization for zones close to the core than occurs experimentally, and less ionization for zones far from the core.

  11. Atomic absorption spectrophotometric and X-ray studies of respirable dusts in Indian coal mines

    SciTech Connect

    Rawat, N.S.; Sinha, J.D.; Sahoo, B.

    1982-01-01

    Quantitative determination of 10 minor and 8 trace elements in respirable coal dust by atomic absorption spectrophotometry is described herein. The coal dust samples were collected in the mine atmosphere during drilling in coal seams. A ''Hexhlet'' appratus specially designed and fitted with a horizontal elutriator was used to collect the respirable coal dust fraction. After destruction of organic matter by wet oxidation and filtering off the clay and silica, iron, calcium, magnesium, sodium, potassium, manganese, zinc, copper, cadmium, and nickel were determined directly in the resulting solution by atomic absorption spectrophotometry. The studies relate to a respiratoy disease-pneumoconiosis-affecting coal mine workers. X-Ray diffraction studies have shown the presence of kaolin, quartz, pirrsonite and beidellite clay minerals in the coal dust.

  12. Atomic structure of machined semiconducting chips: An x-ray absorption spectroscopy study

    SciTech Connect

    Paesler, M.; Sayers, D.

    1988-12-01

    X-ray absorption spectroscopy (XAS) has been used to examine the atomic structure of chips of germanium that were produced by single point diamond machining. It is demonstrated that although the local (nearest neighbor) atomic structure is experimentally quite similar to that of single crystal specimens information from more distant atoms indicates the presence of considerable stress. An outline of the technique is given and the strength of XAS in studying the machining process is demonstrated.

  13. Optical and ultraviolet absorption studies of cool gas in the Milky Way halo

    NASA Technical Reports Server (NTRS)

    Danly, L.

    1990-01-01

    This paper focuses on the contributions from absorption techniques to the knowledge of halo gas with temperatures below 10 to the 5th K. The results from observations of the neutral and singly ionized species on the nature of cool gas in the halo, its structure and its kinematics are presented. An overview of past and optical and ultraviolet observational studies of halo gas is included.

  14. The electronic absorption study of imide anion radicals in terms of time dependent density functional theory

    NASA Astrophysics Data System (ADS)

    Andrzejak, Marcin; Sterzel, Mariusz; Pawlikowski, Marek T.

    2005-07-01

    The absorption spectra of the N-(2,5-di- tert-butylphenyl) phthalimide ( 1-), N-(2,5-di- tert-butylphenyl)-1,8-naphthalimide ( 2-) and N-(2,5-di- tert-butylphenyl)-perylene-3,4-dicarboximide ( 3-) anion radicals are studied in terms of time dependent density functional theory (TDDFT). For these anion radicals a large number electronic states (from 30 to 60) was found in the visible and near-IR regions (5000-45000 cm -1). In these regions the TD/B3LYP treatment at the 6-1+G* level is shown to reproduce satisfactorily the empirical absorption spectra of all three anion radicals studied. The most apparent discrepancies between purely electronic theory and the experiment could be found in the excitation region corresponding to D0→ D1 transitions in the 2- and 3- molecules. For these species we argue that the structures seen in the lowest energy part of the absorptions of the 2- and 3- species are very likely due to Franck-Condon (FC) activity of the totally symmetric vibrations not studied in this Letter.

  15. Water Structure Studied by Far Infrared Spectroscopy in FTIR Beam Line of MIRRORCLE 20

    SciTech Connect

    Miura, Nobuhiro; Moon, Ahsa; Kitagawa, Toshimichi; Yamada, Hironari

    2007-03-30

    Far infrared vibrational Spectroscopy for distilled water was performed by Fourier Transform Infrared Spectroscopy (FT-IR) in the FTIR beam line of MIRRORCLE 20. Synchrotron radiation was utilized as a light source for the absorption Spectroscopy in the frequency range from 100cm-1 to 20cm-1. Off-line measurements by black body radiation of ceramic heater were also examined in the range from 400cm-1 to 50cm-1. Wide range spectrum was obtained after the SR data merged the off-line data. We report the recent development in the beam line and the examples of spectra related to the water structure.

  16. Line identification studies using traditional techniques and wavelength coincidence statistics

    NASA Technical Reports Server (NTRS)

    Cowley, Charles R.; Adelman, Saul J.

    1990-01-01

    Traditional line identification techniques result in the assignment of individual lines to an atomic or ionic species. These methods may be supplemented by wavelength coincidence statistics (WCS). The strength and weakness of these methods are discussed using spectra of a number of normal and peculiar B and A stars that have been studied independently by both methods. The present results support the overall findings of some earlier studies. WCS would be most useful in a first survey, before traditional methods have been applied. WCS can quickly make a global search for all species and in this way may enable identifications of an unexpected spectrum that could easily be omitted entirely from a traditional study. This is illustrated by O I. WCS is a subject to well known weakness of any statistical technique, for example, a predictable number of spurious results are to be expected. The danger of small number statistics are illustrated. WCS is at its best relative to traditional methods in finding a line-rich atomic species that is only weakly present in a complicated stellar spectrum.

  17. Optical time of flight studies of lithium plasma in double pulse laser ablation: Evidence of inverse Bremsstrahlung absorption

    SciTech Connect

    Sivakumaran, V.; Joshi, H. C.; Singh, R. K.; Kumar, Ajai

    2014-06-15

    The early stage of formation of lithium plasma in a collinear—double pulse laser ablation mode has been studied using optical time of flight (OTOF) spectroscopy as a function of inter-pulse delay time, the distance from the target surface and the fluence of the ablation lasers. The experimental TOF measurements were carried out for lithium neutral (670.8 nm and 610.3 nm), and ionic (548.4 nm and 478.8 nm) lines. These experimental observations have been compared with that for single pulse laser ablation mode. It is found that depending on the fluence and laser pulse shape of the first pre-ablation laser and the second main ablation laser, the plasma plume formation and its characteristic features can be described in terms of plume-plume or laser-plume interaction processes. Moreover, the enhancement in the intensity of Li neutral and ionic lines is observed when the laser-plume interaction is the dominant process. Here, we see the evidence of the role of inverse Bremsstrahlung absorption process in the initial stage of formation of lithium plasma in this case.

  18. Unraveling the mysteries of the Leo Ring: An absorption line study of an unusual gas cloud

    SciTech Connect

    Rosenberg, J. L.; Haislmaier, Karl; Giroux, M. L.; Keeney, B. A.; Schneider, S. E.

    2014-07-20

    Since the discovery of the large (2 × 10{sup 9} M{sub ☉}) intergalactic cloud known as the Leo Ring in the 1980s, the origin of this object has been the center of a lively debate. Determining the origin of this object is still important as we develop a deeper understanding of the accretion and feedback processes that shape galaxy evolution. We present Hubble Space Telescope/Cosmic Origins Spectrograph observations of three sightlines near the ring, two of which penetrate the high column density neutral hydrogen gas visible in 21 cm observations of the object. These observations provide the first direct measurement of the metallicity of the gas in the ring, an important clue to its origin. Our best estimate of the metallicity of the ring is ∼10% Z{sub ☉}, higher than expected for primordial gas but lower than expected from an interaction. We discuss possible modifications to the interaction and primordial gas scenarios that would be consistent with this metallicity measurement.

  19. Transcutaneous absorption of oil in preterm babies--a pilot study.

    PubMed

    Fernandez, A R; Krishnamoorthy, G; Patil, N; Mondkar, J A; Swar, B D

    2005-03-01

    This study was conducted to determine transcutaneous absorption of oil in preterm neonates. A mixture of coconut oil and Meadowfoam oil which contains unique fatty acids, which acted as marker fatty acids was applied to the skin of babies. One mL blood was collected before and one hour after post oil application. Both pre and post oil application serum samples were hydrolysed and derivatised with 2-phenyl hydrazine hydrochloride in order to detect fatty acids by HPLC analysis on C-8 column. None of the pre oil application serum sample showed the presence of the marker fatty acids. The post oil application serum sample of all the 12 babies showed the presence of marker fatty acids of Meadowfoam oil which indicates transcutaneous absorption of oil in preterm babies.

  20. Optical-absorption study of RuS2 - xSex single crystals

    NASA Astrophysics Data System (ADS)

    Huang, Jeng-Kuang; Huang, Ying-Sheng; Yang, Tzuen-Rong

    1995-08-01

    An optical-absorption study of synthetic RuS2-xSex single crystals is reported over a temperature range from 80 to 300 K. The data are fitted to several expressions for the shape of the absorption edge, with the best fit being to that expected for indirect allowed transitions. The band gaps at any temperature varies smoothly with the Se composition x, indicating that the nature of the band edges are similar for RuS2, RuSe2, and the compounds of intermediate compositions. The indirect band gaps of various temperatures are determined and their temperature dependence are analyzed by the Varshni equation [Physica 34, 149 (1967)] and an empirical expression proposed by O'Donnell and Chen [Appl. Phys. Lett. 58, 2924 (1991)]. The parameters that describe the temperature dependence of energy gap of RuS2-xSex are evaluated and discussed.

  1. X-ray absorption spectroscopic studies of mononuclear non-heme iron enzymes

    SciTech Connect

    Westre, T.E.

    1996-01-01

    Fe-K-edge X-ray absorption spectroscopy (XAS) has been used to investigate the electronic and geometric structure of the iron active site in non-heme iron enzymes. A new theoretical extended X-ray absorption fine structure (EXAFS) analysis approach, called GNXAS, has been tested on data for iron model complexes to evaluate the utility and reliability of this new technique, especially with respect to the effects of multiple-scattering. In addition, a detailed analysis of the 1s{yields}3d pre-edge feature has been developed as a tool for investigating the oxidation state, spin state, and geometry of iron sites. Edge and EXAFS analyses have then been applied to the study of non-heme iron enzyme active sites.

  2. Review of Russian language studies on radionuclide behaviour in agricultural animals: part 1. Gut absorption.

    PubMed

    Fesenko, S; Isamov, N; Howard, B J; Voigt, G; Beresford, N A; Sanzharova, N

    2007-01-01

    An extensive programme of experiments was conducted in the former USSR on transfer of radionuclides to a wide range of different agricultural animals. Only a few of these studies were made available in the English language literature or taken into account in international reviews of gastrointestinal uptake. The paper gives extended information on Russian research on radionuclide absorption in the gut of farm animals performed in controlled field and laboratory experiments from the 1960s to the current time. The data presented in the paper, together with English language values, will be used to provide recommended values of absorption specifically for farm animals within the revision of the IAEA Handbook of Parameter Values IAEA [International Atomic Energy Agency, 1994. Handbook of Parameter Values for the Prediction of Radionuclide Transfer in Temperate Environments, IAEA technical reports series No. 364. International Atomic Energy Agency, Vienna].

  3. Parametric study of power absorption from electromagnetic waves by small ferrite spheres

    NASA Technical Reports Server (NTRS)

    Englert, Gerald W.

    1989-01-01

    Algebraic expressions in terms of elementary mathematical functions are derived for power absorption and dissipation by eddy currents and magnetic hysteresis in ferrite spheres. Skin depth is determined by using a variable inner radius in descriptive integral equations. Numerical results are presented for sphere diameters less than one wavelength. A generalized power absorption parameter for both eddy currents and hysteresis is expressed in terms of the independent parameters involving wave frequency, sphere radius, resistivity, and complex permeability. In general, the hysteresis phenomenon has a greater sensitivity to these independent parameters than do eddy currents over the ranges of independent parameters studied herein. Working curves are presented for obtaining power losses from input to the independent parameters.

  4. Redox speciation analysis of dissolved iron in estuarine and coastal waters with on-line solid phase extraction and graphite furnace atomic absorption spectrometry detection.

    PubMed

    Chen, Yaojin; Feng, Sichao; Huang, Yongming; Yuan, Dongxing

    2015-05-01

    An automatic on-line solid phase extraction (SPE) system employing the flow injection (FI) technique directly coupled to a graphite furnace atomic absorption spectrometer (GFAAS) was established for speciation and determination of dissolved iron in estuarine and coastal waters. Fe(II) was mixed with ferrozine solution in a sample stream to form the Fe(II)-ferrozine complex which was extracted onto a C18 SPE cartridge, eluted with eluent and detected with GFAAS. In a parallel flow channel, Fe(III) was reduced to Fe(II) with ascorbic acid and then detected in the same way as Fe(II). The home-made interface between FI-SPE and GFAAS efficiently realized the sample introduction to the furnace in a semi-automated way. Parameters of the FI-SPE system and graphite furnace program were optimized based on a univariate experimental design and an orthogonal array design. The salinity effect on the method sensitivity was investigated. The proposed method provided a detection limit of 1.38 nmol L(-1) for Fe(II) and 1.87 nmol L(-1) for Fe(II+III). With variation of the sample loading volume, a broadened determination range of 2.5-200 nmol L(-1) iron could be obtained. The proposed method was successfully applied to analyze iron species in samples collected from the Jiulongjiang Estuary, Fujian, China. With the 2-cartridge FI-SPE system developed, on-line simultaneous determination of Fe species with GFAAS was achieved for the first time.

  5. Tunable diode laser absorption spectroscopy-based tomography system for on-line monitoring of two-dimensional distributions of temperature and H2O mole fraction

    NASA Astrophysics Data System (ADS)

    Xu, Lijun; Liu, Chang; Jing, Wenyang; Cao, Zhang; Xue, Xin; Lin, Yuzhen

    2016-01-01

    To monitor two-dimensional (2D) distributions of temperature and H2O mole fraction, an on-line tomography system based on tunable diode laser absorption spectroscopy (TDLAS) was developed. To the best of the authors' knowledge, this is the first report on a multi-view TDLAS-based system for simultaneous tomographic visualization of temperature and H2O mole fraction in real time. The system consists of two distributed feedback (DFB) laser diodes, a tomographic sensor, electronic circuits, and a computer. The central frequencies of the two DFB laser diodes are at 7444.36 cm-1 (1343.3 nm) and 7185.6 cm-1 (1391.67 nm), respectively. The tomographic sensor is used to generate fan-beam illumination from five views and to produce 60 ray measurements. The electronic circuits not only provide stable temperature and precise current controlling signals for the laser diodes but also can accurately sample the transmitted laser intensities and extract integrated absorbances in real time. Finally, the integrated absorbances are transferred to the computer, in which the 2D distributions of temperature and H2O mole fraction are reconstructed by using a modified Landweber algorithm. In the experiments, the TDLAS-based tomography system was validated by using asymmetric premixed flames with fixed and time-varying equivalent ratios, respectively. The results demonstrate that the system is able to reconstruct the profiles of the 2D distributions of temperature and H2O mole fraction of the flame and effectively capture the dynamics of the combustion process, which exhibits good potential for flame monitoring and on-line combustion diagnosis.

  6. NuSTAR reveals an intrinsically X-ray weak broad absorption line quasar in the ultraluminous infrared galaxy Markarian 231

    SciTech Connect

    Teng, Stacy H.; Rigby, J. R.; Brandt, W. N.; Luo, B.; Harrison, F. A.; Grefenstette, B. W.; Madsen, K. K.; Alexander, D. M.; Gandhi, P.; Bauer, F. E.; Boggs, S. E.; Craig, W. W.; Christensen, F. E.; Comastri, A.; Fabian, A. C.; Farrah, D.; Fiore, F.; Hailey, C. J.; Hickox, R. C.; Ptak, A. F.; and others

    2014-04-10

    We present high-energy (3-30 keV) NuSTAR observations of the nearest quasar, the ultraluminous infrared galaxy (ULIRG) Markarian 231 (Mrk 231), supplemented with new and simultaneous low-energy (0.5-8 keV) data from Chandra. The source was detected, though at much fainter levels than previously reported, likely due to contamination in the large apertures of previous non-focusing hard X-ray telescopes. The full band (0.5-30 keV) X-ray spectrum suggests the active galactic nucleus (AGN) in Mrk 231 is absorbed by a patchy and Compton-thin (N{sub H}∼1.2{sub −0.3}{sup +0.3}×10{sup 23} cm{sup –2}) column. The intrinsic X-ray luminosity (L {sub 0.5–30} {sub keV} ∼ 1.0 × 10{sup 43} erg s{sup –1}) is extremely weak relative to the bolometric luminosity where the 2-10 keV to bolometric luminosity ratio is ∼0.03% compared to the typical values of 2%-15%. Additionally, Mrk 231 has a low X-ray-to-optical power law slope (α{sub OX} ∼ –1.7). It is a local example of a low-ionization broad absorption line quasar that is intrinsically X-ray weak. The weak ionizing continuum may explain the lack of mid-infrared [O IV], [Ne V], and [Ne VI] fine-structure emission lines which are present in sources with otherwise similar AGN properties. We argue that the intrinsic X-ray weakness may be a result of the super-Eddington accretion occurring in the nucleus of this ULIRG, and may also be naturally related to the powerful wind event seen in Mrk 231, a merger remnant escaping from its dusty cocoon.

  7. Redox speciation analysis of dissolved iron in estuarine and coastal waters with on-line solid phase extraction and graphite furnace atomic absorption spectrometry detection.

    PubMed

    Chen, Yaojin; Feng, Sichao; Huang, Yongming; Yuan, Dongxing

    2015-05-01

    An automatic on-line solid phase extraction (SPE) system employing the flow injection (FI) technique directly coupled to a graphite furnace atomic absorption spectrometer (GFAAS) was established for speciation and determination of dissolved iron in estuarine and coastal waters. Fe(II) was mixed with ferrozine solution in a sample stream to form the Fe(II)-ferrozine complex which was extracted onto a C18 SPE cartridge, eluted with eluent and detected with GFAAS. In a parallel flow channel, Fe(III) was reduced to Fe(II) with ascorbic acid and then detected in the same way as Fe(II). The home-made interface between FI-SPE and GFAAS efficiently realized the sample introduction to the furnace in a semi-automated way. Parameters of the FI-SPE system and graphite furnace program were optimized based on a univariate experimental design and an orthogonal array design. The salinity effect on the method sensitivity was investigated. The proposed method provided a detection limit of 1.38 nmol L(-1) for Fe(II) and 1.87 nmol L(-1) for Fe(II+III). With variation of the sample loading volume, a broadened determination range of 2.5-200 nmol L(-1) iron could be obtained. The proposed method was successfully applied to analyze iron species in samples collected from the Jiulongjiang Estuary, Fujian, China. With the 2-cartridge FI-SPE system developed, on-line simultaneous determination of Fe species with GFAAS was achieved for the first time. PMID:25770602

  8. [Study on experiment of absorption spectroscopy detection of pesticide residues of carbendazim in orange juice].

    PubMed

    Ji, Ren-Dong; Chen, Meng-Lan; Zhao, Zhi-Min; Zhu, Xing-Yue; Wang, Le-Xin; Liu, Quan-Jin

    2014-03-01

    Absorption spectra were studied for the carbendazim, in the mixed solution of orange juice and carbendazim using spectrophotometer. The most intensive characteristic peak (285 nm) was found in the spectrum of carbendazim standard solution. Compared with the carbendazim drug solution, the peak position of absorption spectrum has the blue shift (285-280 nm) when carbendazim (0.28 mg x mL(-1))was added in the orange juice. So that we can conclude that interaction happened between the orange juice and carbendazim. Through the method of least squares fitting, the prediction models between the absorbance of orange juice and carbendazim content was obtained with a good linear relationship. The linear function model was: I = 2.41 + 9.26x, the correlation coefficient was 0.996, and the recovery was: 81%-102%. According to the regression model, we can obtain the amount of carbendazim pesticide residues in orange juice. It was verified that the method of using ultraviolet-visible absorption spectra was feasible to detect the carbendazim residues in orange juice. The result proved that it is possible to detect pesticide residues of carbendazim in orange juice, and it can meet the needs of rapid analysis. This study provides a new way for the detection of pesticide residues.

  9. Studies on different iron source absorption by in situ ligated intestinal loops of broilers.

    PubMed

    Jia, Y F; Jiang, M M; Sun, J; Shi, R B; Liu, D S

    2015-02-01

    The objective of this study was to investigate the iron source absorption in the small intestine of broiler. In situ ligated intestinal loops of 70 birds were poured into one of seven solutions, including inorganic iron (FeSO4, Fe2(SO4)3), organic Fe glycine chelate (Fe-Gly(II), Fe-Gly(III)), the mixtures (FeSO4 with glycine (Fe+Gly(II)), Fe2(SO4)3 with glycine (Fe+Gly(III)), and no Fe source (control). The total volume of 3-mL solution (containing 1 mg of elemental Fe) was injected into intestinal loops, and then 120-min incubation was performed. Compared with inorganic iron groups, in which higher FeSO4 absorption than Fe2(SO4)3 was observed, supplementation with organic Fe glycine chelate significantly increased the Fe concentration in the duodenum and jejunum (P < 0.05), however, decreased DMT1 and DcytB messenger RNA (mRNA) levels (P < 0.05). Organic Fe glycine chelate (Fe-Gly(II), Fe-Gly(III)) increased serum iron concentration (SI), compared with inorganic 3 valence iron groups (Fe2(SO4)3 and Fe+Gly(III)) (P < 0.05); moreover, lower TIBC value was observed for the chelate (P < 0.05); however, mixture of inorganic iron and glycine did not have a positive role at DMT1 and DcytB mRNA levels, SI and Fe concentrations in the small intestine. Those results indicated that the absorption of organic Fe glycine chelate was more effective than that of inorganic Fe, and the orders of iron absorption in the small intestine were: Fe-Gly(II), Fe-Gly(III) > FeSO4, Fe+Gly(II) > Fe2(SO4)3, Fe+Gly(III). Additionally, the simple mixture of inorganic iron and glycine could not increase Fe absorption, and the duodenum was the main site of Fe absorption in the intestines of broilers and the ileum absorbed iron rarely.

  10. Numerical and experimental study of the effect of microslits on the normal absorption of structural metamaterials

    NASA Astrophysics Data System (ADS)

    Ruiz, H.; Claeys, C. C.; Deckers, E.; Desmet, W.

    2016-03-01

    Resonant metamaterials are emerging as novel concepts to reduce noise levels in targeted frequency zones, so-called stop bands. The metamaterial concept improves acoustic behaviour through an increase of the insertion loss. This paper concerns a first investigation on the absorption capabilities of a resonant metamaterial when thermo-viscous effects are incorporated via the addition of microslits. In a previous work, a resonant metamaterial was obtained through the inclusion of resonating structures into cavities of an open honeycomb assembly. In this study, the air gap of the honeycomb structure is reduced so as to provide viscous losses for the travelling waves. Considering that the created resonant structures with open cavities are rigid, an equivalent fluid model is used to calculate the acoustical properties of a so called microslit metamaterial. It is demonstrated that the unit cell structure can be divided into parallel elements for which the acoustic impedance can be computed via the transfer matrix approach TMM in parallel and series. Likewise, it is shown that the structural response can be predicted by FEM models allowing studying the structural effects separately from the viscous-thermal effects predicted by the equivalent fluid model. Moreover, the combined effect of both approaches is shown experimentally where it is observed that: (i) The absorption of the resonant metamaterial is increased by the addition of microslits, (ii) the modes of the test sample appear as small peaks on the absorption curve of the microslit metamaterial, (iii) the structural modes are grouped below and above the stop band and, (iv) the resonant structures do not lead to additional absorption in the stop band region. Analytical models are compared to experimental measurements to validate the models and to show the potential of this material assembly.

  11. Spectral line and continuum studies using Haystack antenna

    NASA Technical Reports Server (NTRS)

    1973-01-01

    During the last half of 1972, the Haystack antenna was utilized 88% of the time. Of this useful time, 81% was devoted to radio astronomy investigations, 8% was spent on radar-related research and 11% was scheduled for maintenance and system improvements. Thirteen programs were completed of which 10 were spectral-line studies involving primarily recombination lines and H2O vapor investigations. The others involved 2 cm and 1.3 cm continuum observations. Fifteen new programs were accepted and the currently active radio observing programs totalled 24 as of 31 December 1973. The last radar measurements in the lunar topography program have now been completed. Radar activity, including measurements on Mercury, Venus and synchronous satellites has continued.

  12. Use of factorial design and Doehlert matrix for multivariate optimisation of an on-line preconcentration system for lead determination by flame atomic absorption spectrometry.

    PubMed

    Ferreira, S L C; dos Santos, W N L; Bezerra, M A; Lemos, V A; Bosque-Sendra, J M

    2003-02-01

    A system for on-line preconcentration and determination of lead by flame atomic absorption spectrometry (FAAS) was proposed. It was based on the sorption of lead(II) ions on a minicolumn of polyurethane foam loaded with 2-(2-thiazolylazo)-5-dimethylaminophenol (TAM). The optimisation step was carried out using two-level full factorial and Doehlert designs for the determination of the optimum conditions for lead preconcentration. The proposed procedure allowed the determination of lead with a detection limit of 2.2 microg L(-1), and a precision, calculated as relative standard deviation (RSD), of 2.4 and 6.8 for a lead concentration of 50.0 and 10.0 microg L(-1), respectively. A preconcentration factor of 45 and a sampling frequency of 27 samples per hour were obtained. The recovery achieved for lead determination in the presence of several cations demonstrated that this procedure has enough selectivity for analysis of environmental samples. The validation was carried out by analysis of certified reference material. This procedure was applied to lead determination in natural food. PMID:12589511

  13. On-line preconcentration/determination of zinc from water, biological and food samples using synthesized chelating resin and flame atomic absorption spectrometry.

    PubMed

    Yılmaz, Sibel; Tokalıoğlu, Serife; Sahan, Serkan; Ulgen, Ahmet; Sahan, Ahmet; Soykan, Cengiz

    2013-04-01

    An on-line flow injection pre-concentration-flame atomic absorption spectrometry method was developed to determine trace zinc in water (tap, dam, and well water), biological (hair and nail), and liver samples. As a solid phase extractant, a synthesized new chelating resin, poly(2-thiozylmethacrylamide-co-divinylbenzene-co-2-acrylamido-2-methyl-1-propane sulfonic acid) was used. The resin was characterized by Fourier transform infrared spectroscopy, elemental analysis, and surface area by nitrogen sorption. A pre-concentration factor of 40-fold for a sample volume of 12.6 mL was obtained by using the time-based technique. The detection limit for the pre-concentration method was found to be 2.2 μg L(-1). The precision (as RSD,%) for 10 replicate determinations at the 0.04 μg mL(-1) Zn concentration was 1.2%. The calibration graph using the pre-concentration system for zinc was linear with a correlation coefficient of 0.998 in the concentration range from 0.005 to 0.05 μg mL(-1). The applicability and accuracy of the developed method were estimated by the analysis spiked water, biological, liver samples (83-105%), and also certified reference material TMDA-70 (fortified lake water) and SPS-WW1 Batch 111-Wastewater. The results were in agreement with the certified values.

  14. Modified mesoporous silica materials for on-line separation and preconcentration of hexavalent chromium using a microcolumn coupled with flame atomic absorption spectrometry.

    PubMed

    Wang, Zheng; Fang, Dong-Mei; Li, Qing; Zhang, Ling-Xia; Qian, Rong; Zhu, Yan; Qu, Hai-Yun; Du, Yi-Ping

    2012-05-01

    A modified SBA-15 mesoporous silica material NH(2)-SBA-15 was synthesized successfully by grafting γ-aminopropyl-triethoxysilane. The material was characterized using transmission electron microscopy (TEM) and Fourier transform infrared/Raman (FT-IR/Raman) spectroscopy, and used for the first time in a flow injection on-line solid phase extraction (SPE) coupled with flame atomic absorption spectrometry (FAAS) to detect trace Cr (VI). Effective sorption of Cr (VI) was achieved at pH 2.0 with no interference from Cr (III) and other ions and 0.5 mol L(-1) NH(3)·H(2)O solution was found optimal for the complete elution of Cr (VI). An enrichment factor of 44 and was achieved under optimized experimental conditions at a sample loading of 2.0 mL min(-1) sample loading (300 s) and an elution flow rate of 2.0 mL min(-1) (24s). The precision of the 11 replicate Cr (VI) measurements was 2.1% at the 100 μg L(-1) level with a detection limit of 0.2 μg L(-1) (3s, n=10) using the FAAS. The developed method was successfully applied to trace chromium determination in waste water. The accuracy was validated using a certified reference material of riverine water (GBW08607). PMID:22502615

  15. Determination of Hg(II) in waters by on-line preconcentration using Cyanex 923 as a sorbent — Cold vapor atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Duan, Taicheng; Song, Xuejie; Xu, Jingwei; Guo, Pengran; Chen, Hangting; Li, Hongfei

    2006-09-01

    Using a solid phase extraction mini-column home-made from a neutral extractant Cyanex 923, inorganic Hg could be on-line preconcentrated and simultaneously separated from methyl mercury. The preconcentrated Hg (II) was then eluted with 10% HNO 3 and subsequently reduced by NaBH 4 to form Hg vapor before determination by cold vapor atomic absorption spectrometry (CVAAS). Optimal conditions for and interferences on the Hg preconcentration and measurement were at 1% HCl, for a 25 mL sample uptake volume and a 10 mL min - 1 sample loading rate. The detection limit was 0.2 ng L - 1 and much lower than that of conventional method (around 15.8 ng L - 1 ). The relative standard deviation (RSD) is 1.8% for measurements of 40 ng L - 1 of Hg and the linear working curve is from 20 to 2000 ng L - 1 (with a correlation coefficient of 0.9996). The method was applied in determination of inorganic Hg in city lake and deep well water (from Changchun, Jilin, China), and recovery test results for both samples were satisfactory.

  16. On-line micro-volume introduction system developed for lower density than water extraction solvent and dispersive liquid-liquid microextraction coupled with flame atomic absorption spectrometry.

    PubMed

    Anthemidis, Aristidis N; Mitani, Constantina; Balkatzopoulou, Paschalia; Tzanavaras, Paraskevas D

    2012-07-01

    A simple and fast preconcentration/separation dispersive liquid-liquid micro extraction (DLLME) method for metal determination based on the use of extraction solvent with lower density than water has been developed. For this purpose a novel micro-volume introduction system was developed enabling the on-line injection of the organic solvent into flame atomic absorption spectrometry (FAAS). The effectiveness and efficiency of the proposed system were demonstrated for lead and copper preconcentration in environmental water samples using di-isobutyl ketone (DBIK) as extraction solvent. Under the optimum conditions the enhancement factor for lead and copper was 187 and 310 respectively. For a sample volume of 10 mL, the detection limit (3 s) and the relative standard deviation were 1.2 μg L(-1) and 3.3% for lead and 0.12 μg L(-1) and 2.9% for copper respectively. The developed method was evaluated by analyzing certified reference material and it was applied successfully to the analysis of environmental water samples.

  17. On-line preconcentration and determination of copper, lead and chromium(VI) using unloaded polyurethane foam packed column by flame atomic absorption spectrometry in natural waters and biological samples.

    PubMed

    Anthemidis, Aristidis N; Zachariadis, George A; Stratis, John A

    2002-11-12

    A simple, sensitive and low cost, flow injection time-based method was developed for on-line preconcentration and determination of copper, lead and chromium(VI) at sub mug l(-1) levels in natural waters and biological samples. At the optimum pH, the on-line formed metal-ammonium pyrrolidine dithiocarbamate (APDC) complexes were sorbed on the unloaded commercial polyurethane foam (PUF), and subsequent eluted quantitatively by isobutylmethylketone and determined by flame atomic absorption spectrometry (FAAS). All chemical, and flow injection variables were optimized for the quantitative preconcentration of each metal and a study of interference level of various ions was also carried out. The system offered improved flexibility, low backpressure and applicability to all the studied metals. At a sample frequency of 36 h(-1) and a 60 s preconcentration time, the enhancement factor was 170, 131 and 28, the detection limit was 0.2, 1.8 and 2.0 mug l(-1), and the precision, expressed as relative standard deviation (s(r)), was 2.8 (at 10 mug l(-1)), 3.4 (at 50 mug l(-1)) and 3.6% (at 50 mug l(-1)) for Cu(II), Pb(II) and Cr(VI), respectively. The accuracy of the developed method was sufficient and evaluated by the analysis of certified reference materials and spiked water samples. Finally, the method was applied to the analysis of environmental samples. PMID:18968813

  18. [Study on the absorption and fluorescence spectra of ethylene glycol and glycerol].

    PubMed

    Xu, Hui; Zhu, Tuo; Yu, Rui-Peng

    2007-07-01

    The absorption and fluorescence spectra of ethylene glycol and glycerol solution induced by UV light were studied respectively in the present paper. The most intense absorption wavelength for both of them was located at 198 nm. Moreover, fluorescence was detected when induced by suitable UV light, and the corresponding fluorescence spectra were listed. But there is no obvious relationship found between the fluorescence intensity and the excited wavelength, and a further research should be done. From the first derivative fluorescence spectra of ethylene glycol, it was concluded that under the UV light of 210 nm, the variation speed for relative intensity proved to be the fastest. In contrast, when excited by 225 nm, the speed proved to be the slowest. In addition, based on the quantum calculation and the transition from HOMO to LUMO of electronics in one-dimensional quantum well, the authors attempted to give out the value of absorption wavelength. In consideration of the bond-length variety brought out by the chain processing, the error between the experimental and calculation values should be apprehensible, and the latter can serve as some reference value in theory.

  19. Theoretical study on absorption and emission spectra of pyrrolo-C analogues

    NASA Astrophysics Data System (ADS)

    Liu, Hongxia; Liu, Jianhua; Yang, Yan; Li, Yan; Wang, Haijun

    2015-01-01

    Fluorescent nucleoside analogues have attracted much attention in studying the structure and dynamics of nucleic acids in recent years. In the present work, we use theoretical calculations to investigate the structural and optical properties of Pyrrolo-C (PyC) and its analogues which are modified via the conjugation or fusion of different aromatic ring to the PyC core. We also consider the effects of aqueous solution and base pairing. The results show that the fluorescent pyrrolo-C analogues can pair with guanosine to form stable H-bonded WC base pairs. The calculated absorption peaks of modified deoxyribonucleosides agree well with the measured data. The absorption and emission maxima of the pyrrolo-C analogues are greatly red shifted compared with nature C. The solvent effects can induce wavelength blue shift and increase the oscillator strengths in both the absorption and emission spectra. With regard to the WC base pairs, the B3LYP functional reveals that the lowest energy transitions of modified GC base pairs are charge transfer excitation while the CAM-B3LYP functional predicts that all the lowest transitions are localised on the pyrrolo-C analogues. The M062X and CAM-B3LYP functionals show good agreement with respect to both the value of the lowest energy transitions as well as the oscillator strengths.

  20. A study on collapse behavior and energy absorption capability of Al/CFRP hybrid structural member

    NASA Astrophysics Data System (ADS)

    Hwang, Woo-Chae; Lee, Kil-Sung; Yang, Yong-Jun; Choi, Ju-Ho; Jung, Jong-An; Cha, Cheon-Seok; Yang, In-Young

    2012-04-01

    In vehicle industry, the design of vehicle should be inclined towards the safety performance aspect, at the same time; it also should have weight loss of a vehicles structural member. In this study, experimental investigations are performed for Al/CFRP Hybrid structural members. They are cured by heating to the appropriate curing temperature (130°C) by means of a heater at the vacuum bag of the autoclave. Because the CFRP is an anisotropic material whose mechanical properties, such as strength and elasticity, change with its stacking condition, special attention was given to the effects of the stacking condition on the collapse behavior evaluation of the Al/CFRP Hybrid structural members. The collapse mode and energy absorption capability of the Al/CFRP Hybrid structural members was analyzed with change of the fiber orientation. The stacking condition were selected to investigate the effect of the fiber orientation angle (+/-15°, +/-45°, 90°, 0°/90°and 90°/0° where 0°direction coincides with axis of the member)on the energy absorption of the Al/CFRP Hybrid structural members. The collapse mode and energy absorption capability of Al/CFRP Hybrid structural members was analyzed with change of the fiber orientation of CFRP.

  1. A study on collapse behavior and energy absorption capability of Al/CFRP hybrid structural member

    NASA Astrophysics Data System (ADS)

    Hwang, Woo-Chae; Lee, Kil-Sung; Yang, Yong-Jun; Choi, Ju-Ho; Jung, Jong-An; Cha, Cheon-Seok; Yang, In-Young

    2011-11-01

    In vehicle industry, the design of vehicle should be inclined towards the safety performance aspect, at the same time; it also should have weight loss of a vehicles structural member. In this study, experimental investigations are performed for Al/CFRP Hybrid structural members. They are cured by heating to the appropriate curing temperature (130°C) by means of a heater at the vacuum bag of the autoclave. Because the CFRP is an anisotropic material whose mechanical properties, such as strength and elasticity, change with its stacking condition, special attention was given to the effects of the stacking condition on the collapse behavior evaluation of the Al/CFRP Hybrid structural members. The collapse mode and energy absorption capability of the Al/CFRP Hybrid structural members was analyzed with change of the fiber orientation. The stacking condition were selected to investigate the effect of the fiber orientation angle (+/-15°, +/-45°, 90°, 0°/90°and 90°/0° where 0°direction coincides with axis of the member)on the energy absorption of the Al/CFRP Hybrid structural members. The collapse mode and energy absorption capability of Al/CFRP Hybrid structural members was analyzed with change of the fiber orientation of CFRP.

  2. [Simulation of TDLAS direct absorption based on HITRAN database].

    PubMed

    Qi, Ru-birn; He, Shu-kai; Li, Xin-tian; Wang, Xian-zhong

    2015-01-01

    Simulating of the direct absorption TDLAS spectrum can help to comprehend the process of the absorbing and understand the influence on the absorption signal with each physical parameter. Firstly, the basic theory and algorithm of direct absorption TDLAS is studied and analyzed thoroughly, through giving the expressions and calculating steps of parameters based on Lambert-Beer's law, such as line intensity, absorption cross sections, concentration, line shape and gas total partition functions. The process of direct absorption TDLAS is simulated using MATLAB programs based on HITRAN spectra database, with which the absorptions under a certain temperature, pressure, concentration and other conditions were calculated, Water vapor is selected as the target gas, the absorptions of which under every line shapes were simulated. The results were compared with that of the commercial simulation software, Hitran-PC, which showed that, the deviation under Lorentz line shape is less than 0. 5%, and that under Gauss line shape is less than 2. 5%, while under Voigt line shape it is less than 1%. It verified that the algorithm and results of this work are correct and accurate. The absorption of H2O in v2 + v3 band under different pressure and temperature is also simulated. In low pressure range, the Doppler broadening dominant, so the line width changes little with varied.pressure, while the line peak increases with rising pressure. In high pressure range, the collision broadening dominant, so the line width changes wider with increasing pressure, while the line peak approaches to a constant value with rising pressure. And finally, the temperature correction curve in atmosphere detection is also given. The results of this work offer the reference and instruction for the application of TDLAS direct absorption. PMID:25993843

  3. EPR, optical absorption and luminescence studies of Cr3+-doped antimony phosphate glasses

    NASA Astrophysics Data System (ADS)

    De Vicente, F. S.; Santos, F. A.; Simões, B. S.; Dias, S. T.; Siu Li, M.

    2014-12-01

    Antimony phosphate glasses (SbPO) doped with 3 and 6 mol% of Cr3+ were studied by Electron Paramagnetic Resonance (EPR), UV-VIS optical absorption and luminescence spectroscopy. The EPR spectra of Cr3+-doped glasses showed two principal resonance signals with effective g values at g = 5.11 and g = 1.97. UV-VIS optical absorption spectra of SbPO:Cr3+ presented four characteristics bands at 457, 641, 675, and 705 nm related to the transitions from 4A2(F) to 4T1(F), 4T2(F), 2T1(G), and 2E(G), respectively, of Cr3+ ions in octahedral symmetry. Optical absorption spectra of SbPO:Cr3+ allowed evaluating the crystalline field Dq, Racah parameters (B and C) and Dq/B. The calculated value of Dq/B = 2.48 indicates that Cr3+ ions in SbPO glasses are in strong ligand field sites. The optical band gap for SbPO and SbPO:Cr3+ were evaluated from the UV optical absorption edges. Luminescence measurements of pure and Cr3+-doped glasses excited with 350 nm revealed weak emission bands from 400 to 600 nm due to the 3P1 → 1S0 electronic transition from Sb3+ ions. Cr3+-doped glasses excited with 415 nm presented Cr3+ characteristic luminescence spectra composed by two broad bands, one band centered at 645 nm (2E → 4A2) and another intense band from 700 to 850 nm (4T2 → 4A2).

  4. Thermal structure and CO distribution for the Venus mesosphere/lower thermosphere: 2001-2009 inferior conjunction sub-millimeter CO absorption line observations

    NASA Astrophysics Data System (ADS)

    Clancy, R. Todd; Sandor, Brad J.; Moriarty-Schieven, Gerald

    2012-02-01

    Sub-millimeter 12CO (346 GHz) and 13CO (330 GHz) line absorptions, formed in the mesosphere and lower thermosphere of Venus (70-120 km), have been mapped across the nightside Venus disk during 2001-2009 inferior conjunctions, employing the James Clerk Maxwell Telescope (JCMT). Radiative transfer analysis of these thermal line absorptions supports temperature and CO mixing profile retrievals, as well as Doppler wind fields (described in the companion paper, Clancy et al., 2012). Temporal sampling over the hourly, daily, weekly and interannual timescales was obtained over 2001-2009. On timescales inferred as several weeks, we observe changes between very distinctive CO and temperature nightside distributions. Retrieved nightside CO, temperature distributions for January 2006 and August 2007 observations display strong local time, latitudinal gradients consistent with early morning (2-3 am), low-to-mid latitude (0-40NS) peaks of 100-200% in CO and 20-30 K in temperature. The temperature increases are most pronounced above 100 km altitudes, whereas CO variations extend from 105 km (top altitude of retrieval) down to below 80 km in the mesosphere. In contrast, the 2004 and 2009 periods of observation display modest temperature (5-10 K) and CO (30-60%) increases, that are centered on antisolar (midnight) local times and equatorial latitudes. Doppler wind derived global (zonal and should be SSAS) circulations from the same data do not exhibit variations correlated with these CO, temperature short-term variations. However, large-scale residual wind fields not fit by the zonal, SSAS circulations are observed in concert with the strong temperature, CO gradients observed in 2006 and 2007 (Clancy et al., 2010). These short term variations in nightside CO, temperature distributions may also be related to observed nightside variations in O 2 airglow (Hueso, H., Sánchez-Lavega, A., Piccioni, G., Drossart, P., Gérard, J.C., Khatuntsev, I., Zasova, L., Migliorini, A. [2008]. J

  5. Energy absorption ability of buckyball C720 at low impact speed: a numerical study based on molecular dynamics

    PubMed Central

    2013-01-01

    The dynamic impact response of giant buckyball C720 is investigated by using molecular dynamics simulations. The non-recoverable deformation of C720 makes it an ideal candidate for high-performance energy absorption. Firstly, mechanical behaviors under dynamic impact and low-speed crushing are simulated and modeled, which clarifies the buckling-related energy absorption mechanism. One-dimensional C720 arrays (both vertical and horizontal alignments) are studied at various impact speeds, which show that the energy absorption ability is dominated by the impact energy per buckyball and less sensitive to the number and arrangement direction of buckyballs. Three-dimensional stacking of buckyballs in simple cubic, body-centered cubic, hexagonal, and face-centered cubic forms are investigated. Stacking form with higher occupation density yields higher energy absorption. The present study may shed lights on employing C720 assembly as an advanced energy absorption system against low-speed impacts. PMID:23360618

  6. In-situ x-ray absorption study of copper films in ground watersolutions

    SciTech Connect

    Kvashnina, K.O.; Butorin, S.M.; Modin, A.; Soroka, I.; Marcellini, M.; Nordgren, J.; Guo, J.-H.; Werme, L.

    2007-10-29

    This study illustrates how the damage from copper corrosion can be reduced by modifying the chemistry of the copper surface environment. The surface modification of oxidized copper films induced by chemical reaction with Cl{sup -} and HCO{sub 3}{sup -} in aqueous solutions was monitored by in situ X-ray absorption spectroscopy. The results show that corrosion of copper can be significantly reduced by adding even a small amount of sodium bicarbonate. The studied copper films corroded quickly in chloride solutions, whereas the same solution containing 1.1 mM HCO{sub 3}{sup -} prevented or slowed down the corrosion processes.

  7. Incorporation of Trace Elements in Ancient and Modern Human Bone: An X-Ray Absorption Spectroscopy Study

    NASA Astrophysics Data System (ADS)

    Pingitore, N. E.; Cruz-Jimenez, G.; Price, T. D.

    2001-12-01

    X-ray absorption spectroscopy (XAS) affords the opportunity to probe the atomic environment of trace elements in human bone. We are using XAS to investigate the mode(s) of incorporation of Sr, Zn, Pb, and Ba in both modern and ancient (and thus possibly altered) human and animal bone. Because burial and diagenesis may add trace elements to bone, we performed XAS analysis on samples of pristine contemporary and ancient, buried human and animal bone. We assume that deposition of these elements during burial occurs by processes distinct from those in vivo, and this will be reflected in their atomic environments. Archaeologists measure strontium in human and animal bone as a guide to diet. Carnivores show lower Sr/Ca ratios than their herbivore prey due to discrimination against Sr relative to Ca up the food chain. In an initial sample suite no difference was observed between modern and buried bone. Analysis of additional buried samples, using a more sensitive detector, revealed significant differences in the distance to the second and third neighbors of the Sr in some of the buried samples. Distances to the first neighbor, oxygen, were similar in all samples. Zinc is also used in paleo-diet studies. Initial x-ray absorption spectroscopy of a limited suite of bones did not reveal any differences between modern and buried samples. This may reflect the limited number of samples examined or the low levels of Zn in typical aqueous solutions in soils. Signals from barium and lead were too low to record useful XAS spectra. Additional samples will be studied for Zn, Ba, and Pb. We conducted our XAS experiments on beam lines 4-1 and 4-3 at the Stanford Synchrotron Radiation Laboratory. Data were collected in the fluorescence mode, using a Lytle detector and appropriate filter, and a solid state, 13-element Ge-detector.

  8. More Constraints on the Physical Conditions of the Kinematically Complex, Multiphase Absorption Line System at z=0.93 toward PG1206+459

    NASA Astrophysics Data System (ADS)

    Rosenwasser, Ben; Muzahid, Sowgat; Norris, Jackson; Charlton, Jane C.

    2015-01-01

    We present the results of photo- and collisional ionization modeling of the strong MgII absorption system at redshift z~0.93 towards the quasar PG1206+459. This system has been extensively studied over the last two decades (Churchill & Charlton 1999; Ding et al. 2003; Tripp et al. 2011) using a combination of spectra from Keck/HIRES, HST/FOS, HST/STIS, and HST/COS. Here we present newconstraints using the most complete spectral coverage including more recent observations of OVI and the Lyman series from HST/COS. Numerous absorption components are seen over a large velocity spread (~1500km/s), and multiple ionization phases are required to account for the detected transitions, which include MgI, MgII, FeII, SiII, SiIII, SiIV, CII, CIII, CIV, SIII, SIV, SV, SVI, NIII, NIV, NV, OIII, OIV, OV, OVI, and NeVIII. Considering the new constraints, we revisit the question of the physical nature of the structures that produce this absorber.

  9. X-ray absorption spectroscopy and EPR studies of oriented spinach thylakoid preparations

    SciTech Connect

    Andrews, J.C. |

    1995-08-01

    In this study, oriented Photosystem II (PS II) particles from spinach chloroplasts are studied with electron paramagnetic resonance (EPR) and x-ray absorption spectroscopy (XAS) to determine more details of the structure of the oxygen evolving complex (OEC). The nature of halide binding to Mn is also studied with Cl K-edge and Mn EXAFS (extended x-ray absorption fine structure) of Mn-Cl model compounds, and with Mn EXAFS of oriented PS II in which Br has replaced Cl. Attention is focused on the following: photosynthesis and the oxygen evolving complex; determination of mosaic spread in oriented photosystem II particles from signal II EPR measurement; oriented EXAFS--studies of PS II in the S{sub 2} state; structural changes in PS II as a result of treatment with ammonia: EPR and XAS studies; studies of halide binding to Mn: Cl K-edge and Mn EXAFS of Mn-Cl model compounds and Mn EXAFS of oriented Br-treated photosystem II.

  10. Scenario for concurrent conceptual assembly line design: A case study

    NASA Astrophysics Data System (ADS)

    Mas, F.; Ríos, J.; Menéndez, J. L.

    2012-04-01

    The decision to design and build a new aircraft is preceded by years of research and study. Different disciplines work together throughout the lifecycle to ensure not only a complete functional definition of the product, but also a complete industrialization, a marketing plan, a maintenance plan, etc. This case study focuses on the conceptual design phase. During this phase, the design solutions that will meet the functional and industrial requirements are defined, i.e.: the basic requirements of industrialization. During this phase, several alternatives are studied, and the most attractive in terms of performance and cost requirements is selected. As a result of the study of these alternatives, it is possible to define an early conceptual design of the assembly line and its basic parameters. The plant needs, long cycle jigs & tools or industrial means and human resources with the necessary skills can be determined in advance.

  11. First theoretical global line lists of ethylene (12C2H4) spectra for the temperature range 50-700 K in the far-infrared for quantification of absorption and emission in planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Rey, M.; Delahaye, T.; Nikitin, A. V.; Tyuterev, Vl. G.

    2016-10-01

    We present the construction of complete and comprehensive ethylene line lists for the temperatures 50-700 K based on accurate ab initio potential and dipole moment surfaces and extensive first-principle calculations. Three lists spanning the [0-6400] cm-1 infrared region were built at T = 80, 160, and 296 K, and two lists in the range [0-5200] cm-1 were built at 500 and 700 K. For each of these five temperatures, we considered possible convergence problems to ensure reliable opacity calculations. Our final list at 700 K was computed up to J = 71 and contains almost 60 million lines for intensities I > 5 × 10-27 cm/molecule. Comparisons with experimental spectra carried out in this study showed that for the most active infrared bands, the accuracy of band centers in our theoretical lists is better on average than 0.3 cm-1, and the integrated absorbance errors in the intervals relevant for spectral analyses are about 1-3%. These lists can be applied to simulations of absorption and emission spectra, radiative and non-LTE processes, and opacity calculations for planetary and astrophysical applications. The lists are freely accessible through the TheoReTS information system at http://theorets.univ-reims.fr and http://theorets.tsu.ru

  12. In vitro predictions of skin absorption of caffeine, testosterone, and benzoic acid: a multi-centre comparison study.

    PubMed

    van de Sandt, J J M; van Burgsteden, J A; Cage, S; Carmichael, P L; Dick, I; Kenyon, S; Korinth, G; Larese, F; Limasset, J C; Maas, W J M; Montomoli, L; Nielsen, J B; Payan, J-P; Robinson, E; Sartorelli, P; Schaller, K H; Wilkinson, S C; Williams, F M

    2004-06-01

    To obtain better insight into the robustness of in vitro percutaneous absorption methodology, the intra- and inter-laboratory variation in this type of study was investigated in 10 European laboratories. To this purpose, the in vitro absorption of three compounds through human skin (9 laboratories) and rat skin (1 laboratory) was determined. The test materials were benzoic acid, caffeine, and testosterone, representing a range of different physico-chemical properties. All laboratories performed their studies according to a detailed protocol in which all experimental details were described and each laboratory performed at least three independent experiments for each test chemical. All laboratories assigned the absorption of benzoic acid through human skin, the highest ranking of the three compounds (overall mean flux of 16.54+/-11.87 microg/cm(2)/h). The absorption of caffeine and testosterone through human skin was similar, having overall mean maximum absorption rates of 2.24+/-1.43 microg/cm(2)/h and 1.63+/-1.94 microg/cm(2)/h, respectively. In 7 out of 9 laboratories, the maximum absorption rates of caffeine were ranked higher than testosterone. No differences were observed between the mean absorption through human skin and the one rat study for benzoic acid and testosterone. For caffeine the maximum absorption rate and the total penetration through rat skin were clearly higher than the mean value for human skin. When evaluating all data, it appeared that no consistent relation existed between the diffusion cell type and the absorption of the test compounds. Skin thickness only slightly influenced the absorption of benzoic acid and caffeine. In contrast, the maximum absorption rate of testoster