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

NASA Technical Reports Server (NTRS)

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

2010-01-01

We present evidence for X-ray line emitting and absorbing gas in the nucleus of the Broad-Line Radio Galaxy (BLRG), 3C445. A 200 ks Chandra LETG observation of 3C 445 reveals the presence of several highly ionized emission lines in the soft X-ray spectrum, primarily from the He and H-like ions of O, Ne, Mg and Si. Radiative recombination emission is detected from O VII and O VIII, indicating that the emitting gas is photoionized. The He-like emission appears to be resolved into forbidden and intercombination line components, which implies a high density of greater than 10(sup 10) cm(sup -3), while the lines are velocity broadened with a mean width of 2600 km s(sup -1). The density and widths of the ionized lines indicate an origin of the gas on sub-parsec scales in the Broad Line Region (BLR). The X-ray continuum of 3C 445 is heavily obscured by a photoionized absorber of column density N(sub H) = 2 x 10(sup 23) cm(sup -2) and ionization parameter log xi = 1.4 erg cm s(sup -1). However the view of the X-ray line emission is unobscured, which requires the absorber to be located at radii well within any parsec scale molecular torus. Instead we suggest that the X-ray absorber in 3C 445 may be associated with an outflowing, but clumpy accretion disk wind, with an observed outflow velocity of approximately 10000 km s(sup -1).

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;

Extending the Calibration of C IV-based Single-epoch Black Hole Mass Estimators for Active Galactic Nuclei

NASA Astrophysics Data System (ADS)

Park, Daeseong; Barth, Aaron J.; Woo, Jong-Hak; Malkan, Matthew A.; Treu, Tommaso; Bennert, Vardha N.; Assef, Roberto J.; Pancoast, Anna

2017-04-01

We provide an updated calibration of C IV λ 1549 broad emission line–based single-epoch (SE) black hole (BH) mass estimators for active galactic nuclei (AGNs) using new data for six reverberation-mapped AGNs at redshift z=0.005{--}0.028 with BH masses (bolometric luminosities) in the range {10}6.5{--}{10}7.5 {M}ȯ ({10}41.7{--}{10}43.8 erg s‑1). New rest-frame UV-to-optical spectra covering 1150–5700 Å for the six AGNs were obtained with the Hubble Space Telescope (HST). Multicomponent spectral decompositions of the HST spectra were used to measure SE emission-line widths for the C IV, Mg II, and Hβ lines, as well as continuum luminosities in the spectral region around each line. We combine the new data with similar measurements for a previous archival sample of 25 AGNs to derive the most consistent and accurate calibrations of the C IV-based SE BH mass estimators against the Hβ reverberation-based masses, using three different measures of broad-line width: full width at half maximum (FWHM), line dispersion ({σ }line}), and mean absolute deviation (MAD). The newly expanded sample at redshift z=0.005{--}0.234 covers a dynamic range in BH mass (bolometric luminosity) of {log}{M}BH}/{M}ȯ =6.5{--}9.1 ({log}{L}bol}/ erg s‑1 = 41.7{--}46.9), and we derive the new C IV-based mass estimators using a Bayesian linear regression analysis over this range. We generally recommend the use of {σ }line} or MAD rather than FWHM to obtain a less biased velocity measurement of the C IV emission line, because its narrow-line component contribution is difficult to decompose from the broad-line profile. 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 NAS 5-26555. These observations are associated with program GO-12922.

A near-infrared relationship for estimating black hole masses in active galactic nuclei

NASA Astrophysics Data System (ADS)

Landt, Hermine; Ward, Martin J.; Peterson, Bradley M.; Bentz, Misty C.; Elvis, Martin; Korista, Kirk T.; Karovska, Margarita

2013-06-01

Black hole masses for samples of active galactic nuclei (AGN) are currently estimated from single-epoch optical spectra using scaling relations anchored in reverberation mapping results. In particular, the two quantities needed for calculating black hole masses, namely the velocity and the radial distance of the orbiting gas are derived from the widths of the Balmer hydrogen broad emission lines and the optical continuum luminosity, respectively. We have recently presented a near-infrared (near-IR) relationship for estimating AGN black hole masses based on the widths of the Paschen hydrogen broad emission lines and the total 1 μm continuum luminosity. The near-IR offers several advantages over the optical: it suffers less from dust extinction, the AGN continuum is observed only weakly contaminated by the host galaxy and the strongest Paschen broad emission lines Paα and Paβ are unblended. Here, we improve the calibration of the near-IR black hole mass relationship by increasing the sample from 14 to 23 reverberation-mapped AGN using additional spectroscopy obtained with the Gemini Near-Infrared Spectrograph. The additional sample improves the number statistics in particular at the high-luminosity end.

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

NASA Astrophysics Data System (ADS)

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

2014-03-01

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

Spatial resolution of a hard x-ray CCD detector.

PubMed

Seely, John F; Pereira, Nino R; Weber, Bruce V; Schumer, Joseph W; Apruzese, John P; Hudson, Lawrence T; Szabo, Csilla I; Boyer, Craig N; Skirlo, Scott

2010-08-10

The spatial resolution of an x-ray CCD detector was determined from the widths of the tungsten x-ray lines in the spectrum formed by a crystal spectrometer in the 58 to 70 keV energy range. The detector had 20 microm pixel, 1700 by 1200 pixel format, and a CsI x-ray conversion scintillator. The spectral lines from a megavolt x-ray generator were focused on the spectrometer's Rowland circle by a curved transmission crystal. The line shapes were Lorentzian with an average width after removal of the natural and instrumental line widths of 95 microm (4.75 pixels). A high spatial frequency background, primarily resulting from scattered gamma rays, was removed from the spectral image by Fourier analysis. The spectral lines, having low spatial frequency in the direction perpendicular to the dispersion, were enhanced by partially removing the Lorentzian line shape and by fitting Lorentzian curves to broad unresolved spectral features. This demonstrates the ability to improve the spectral resolution of hard x-ray spectra that are recorded by a CCD detector with well-characterized intrinsic spatial resolution.

Properties of Narrow line Seyfert 1 galaxies

NASA Astrophysics Data System (ADS)

Rakshit, Suvendu; Stalin, Chelliah Subramonian; Chand, Hum; Zhang, Xue-Guang

2018-04-01

Narrow line Seyfert 1 (NLSy1) galaxies constitute a class of active galactic nuclei characterized by the full width at half maximum (FWHM) of the Hα broad emission line <2000 km s-1 and the flux ratio of [O III] to Hα <3. Their properties are not well understood since only a few NLSy1 galaxies were known earlier. We have studied various properties of NLSy1 galaxies using an enlarged sample and compared them with the conventional broad-line Seyfert 1 (BLSy1) galaxies. Both the sample of sources have z˜ 0.8 and their optical spectra from SDSS-DR12 that are used to derive various physical parameters have a median signal to noise (S/N) ratio >10 pixel-1. A strong correlation between the Hα and Hα emission lines is found both in the FWHM and flux. The nuclear continuum luminosity is found to be strongly correlated with the luminosity of Hα, Hα and [O III] emission lines. The black hole mass in NLSy1 galaxies is lower compared to their broad line counterparts. Compared to BLSy1 galaxies, NLSy1 galaxies have a stronger FeII emission and a higher Eddington ratio that place them in the extreme upper right corner of the R4570 - λEdd diagram. The distribution of the radio-loudness parameter (R) in NLSy1 galaxies drops rapidly at R>10 compared to the BLSy1 galaxies that have powerful radio jets. The soft X-ray photon index in NLSy1 galaxies is on average higher (2.9 ± 0.9) than BLSy1 galaxies (2.4 ± 0.8). It is anti-correlated with the Hα width but correlated with the FeII strength. NLSy1 galaxies on average have a lower amplitude of optical variability compared to their broad lines counterparts. These results suggest Eddington ratio as the main parameter that drives optical variability in these sources.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Negrete, C. Alenka; Dultzin, Deborah; Marziani, Paola

2013-07-01

Black hole mass estimation in quasars, especially at high redshift, involves the use of single-epoch spectra with signal-to-noise ratio and resolution that permit accurate measurement of the width of a broad line assumed to be a reliable virial estimator. Coupled with an estimate of the radius of the broad-line region (BLR) this yields the black hole mass M{sub BH}. The radius of the BLR may be inferred from an extrapolation of the correlation between source luminosity and reverberation-derived r{sub BLR} measures (the so-called Kaspi relation involving about 60 low-z sources). We are exploring a different method for estimating r{sub BLR}more » directly from inferred physical conditions in the BLR of each source. We report here on a comparison of r{sub BLR} estimates that come from our method and from reverberation mapping. Our ''photoionization'' method employs diagnostic line intensity ratios in the rest-frame range 1400-2000 A (Al III {lambda}1860/Si III] {lambda}1892, C IV {lambda}1549/Al III {lambda}1860) that enable derivation of the product of density and ionization parameter with the BLR distance derived from the definition of the ionization parameter. We find good agreement between our estimates of the density, ionization parameter, and r{sub BLR} and those from reverberation mapping. We suggest empirical corrections to improve the agreement between individual photoionization-derived r{sub BLR} values and those obtained from reverberation mapping. The results in this paper can be exploited to estimate M{sub BH} for large samples of high-z quasars using an appropriate virial broadening estimator. We show that the width of the UV intermediate emission lines are consistent with the width of H{beta}, thereby providing a reliable virial broadening estimator that can be measured in large samples of high-z quasars.« less

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

NASA Technical Reports Server (NTRS)

Moore, David; Cohen, Ross D.

1996-01-01

We present model line profiles of [O II] lambda3727, [Ne III] lambda3869, [O I] lambda5007, [Fe VII] lambda6087, [Fe X] lambda6374, [O I] lambda6300, H(alpha) lambda6563, and [S 2] lambda6731. The profiles presented here illustrate explicitly the pronounced effects that collisional de-excitation, and that spatial variations in both the ionization parameter and cloud column density, have on Narrow-Line Region (NLR) model profiles. The above effects were included only qualitatively in a previous analytical treatment by Moore and Cohen. By making a direct correspondence between these model profiles and the analytical model profiles of Moore and Cohen, and by comparing with the observed profiles presented in a companion paper and also with those presented elsewhere in the literature, we strengthen some of the conclusions of Moore and Cohen. Most notably, we argue for constant ionization parameter, uniformly accelerated outflow of clouds that are individually stratified in ionization, and the interpretation of emission-line width correlations with ionization potential as a column density effect. For comparison with previous observational studies, such as our own in a companion paper, we also calculate profile parameters for some of the models, and we present and discuss the resulting line width correlations with critical density (n(sub cr)) and Ionization Potential (IP). Because the models we favor are those that produce extended profile wings as observed in high spectral resolution studies, the line width correlations of our favoured models are of particular interest. Line width correlations with n(sub cr) and/or IP result only if the width parameter is more sensitive to extended profile wings than is the Full Width at Half-Maximum (FWHM). Correlations between FWHM and n(sub cr) and/or IP result only after convolving the model profiles with a broad instrumental profile that simulates the lower spectral resolution used in early observational studies. The model in agreement with the greatest number of observational considerations has electron density decreasing outward from n(sub e) approx. equals 10(exp 6)/cu cm to n(sub e) approx. equals 10(exp 2)/cu cm and, due to collisional de-excitation effects in the lowest velocity clouds, it generates broad flat-topped profile peaks in the lines of lowest critical density (e.g., [O II] lambda3727 and [S II] lambda(lambda)6716, 6731). Because the observed profile peaks of both low and high critical density lines are often very similar, our favored model requires a contribution to NLR emission-line spectra from low-velocity, low-density, and low-ionization gas not included in the model NLR.

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

NASA Astrophysics Data System (ADS)

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

2002-03-01

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

DETECTION OF THE INTERMEDIATE-WIDTH EMISSION LINE REGION IN QUASAR OI 287 WITH THE BROAD EMISSION LINE REGION OBSCURED BY THE DUSTY TORUS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Zhenzhen; Zhou, Hongyan; Wang, Huiyuan

2015-10-20

The existence of intermediate-width emission line regions (IELRs) in active galactic nuclei has been discussed for over two decades. A consensus, however, is yet to be arrived at due to the lack of convincing evidence for their detection. We present a detailed analysis of the broadband spectrophotometry of the partially obscured quasar OI 287. The ultraviolet intermediate-width emission lines (IELs) are very prominent, in high contrast to the corresponding broad emission lines (BELs) which are heavily suppressed by dust reddening. Assuming that the IELR is virialized, we estimated its distance to the central black hole to be ∼2.9 pc, similarmore » to the dust sublimation radius of ∼1.3 pc. Photo-ionization calculations suggest that the IELR has a hydrogen density of ∼10{sup 8.8}–10{sup 9.4} cm{sup −3}, within the range of values quoted for the dusty torus near the sublimation radius. Both its inferred location and physical conditions suggest that the IELR originates from the inner surface of the dusty torus. In the spectrum of this quasar, we identified only one narrow absorption-line system associated with the dusty material. With the aid of photo-ionization model calculations, we found that the obscuring material might originate from an outer region of the dusty torus. We speculate that the dusty torus, which is exposed to the central ionizing source, may produce IELs through photo-ionization processes, as well as obscure BELs as a natural “coronagraph.” Such a “coronagraph” could be found in a large number of partially obscured quasars and may be a useful tool to study IELRs.« less

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nobuta, K.; Akiyama, M.; Ueda, Y.

2012-12-20

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

POX 52: A Dwarf Seyfert 1 Galaxy with an Intermediate-Mass Black Hole

NASA Astrophysics Data System (ADS)

Barth, Aaron J.; Ho, Luis C.; Rutledge, Robert E.; Sargent, Wallace L. W.

2004-05-01

We describe new optical images and spectra of POX 52, a dwarf galaxy with an active nucleus that was originally detected in the POX objective-prism survey. While POX 52 was originally thought to be a Seyfert 2 galaxy, the new data reveal an emission-line spectrum very similar to that of the dwarf Seyfert 1 galaxy NGC 4395, with broad components to the permitted line profiles, and we classify POX 52 as a Seyfert 1 galaxy. The host galaxy appears to be a dwarf elliptical, and its brightness profile is best fit by a Sérsic model with an index of 3.6+/-0.2 and a total magnitude of MV=-17.6. Applying mass-luminosity-line width scaling relations to estimate the black hole mass from the broad Hβ line width and nonstellar continuum luminosity, we find MBH~1.6×105Msolar. The stellar velocity dispersion in the host galaxy, measured from the Ca II λ8498, 8542 lines, is 36+/-5 km s-1, also suggestive of a black hole mass of order 105Msolar. Further searches for active nuclei in dwarf galaxies can provide unique constraints on the demographics of black holes in the mass range below 106Msolar.

QSO Narrow [OIII] Line Width and Host Galaxy Luminosity

NASA Astrophysics Data System (ADS)

Bonning, E. W.; Shields, G. A.; Salviander, S.

2004-05-01

Established correlations between galaxy bulge luminosity L, black hole mass MBH, and stellar velocity dispersion sigma in galaxies suggest a close relationship between the growth of supermassive black holes and their host galaxies. Measurements of the MBH - sigma relationship as a function of cosmic time may shed light on the origin of this relationship. One approach is to derive MBH and sigma from the widths of QSO broad and narrow lines, respectively (Shields et al. 2003, ApJ, 583, 124; Nelson 2000, ApJ, 544, L91). We investigate the utility of using the velocity of the narrow line emitting gas as a surrogate for stellar velocity dispersion in QSOs by examining host magnitudes and [OIII] line widths for low redshift QSOs. For our limited range of L, the increase in sigma with L predicted by the Faber-Jackson relation is substantially obscured by scatter. However, sigma([O III]) is consistent in the mean with host galaxy luminosity. EWB is a NASA GSRP fellow. GAS and SS are supported under Texas Advanced Research Program grant 003658-0177-2001 and NSF grant AST-0098594.

Unusual broad-line Mg II emitters among luminous galaxies in the baryon oscillation spectroscopic survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2014-02-01

Many classes of active galactic nuclei (AGNs) have been observed and recorded since the discovery of Seyfert galaxies. In this paper, we examine the sample of luminous galaxies in the Baryon Oscillation Spectroscopic Survey. We find a potentially new observational class of AGNs, one with strong and broad Mg II λ2799 line emission, but very weak emission in other normal indicators of AGN activity, such as the broad-line Hα, Hβ, and the near-ultraviolet AGN continuum, leading to an extreme ratio of broad Hα/Mg II flux relative to normal quasars. Meanwhile, these objects' narrow-line flux ratios reveal AGN narrow-line regions withmore » levels of activity consistent with the Mg II fluxes and in agreement with that of normal quasars. These AGN may represent an extreme case of the Baldwin effect, with very low continuum and high equivalent width relative to typical quasars, but their ratio of broad Mg II to broad Balmer emission remains very unusual. They may also be representative of a class of AGN where the central engine is observed indirectly with scattered light. These galaxies represent a small fraction of the total population of luminous galaxies (≅ 0.1%), but are more likely (about 3.5 times) to have AGN-like nuclear line emission properties than other luminous galaxies. Because Mg II is usually inaccessible for the population of nearby galaxies, there may exist a related population of broad-line Mg II emitters in the local universe which is currently classified as narrow-line emitters (Seyfert 2 galaxies) or low ionization nuclear emission-line regions.« less

The Case for Optically Thick High-Velocity Broad-Line Region Gas in Active Galactic Nuclei

NASA Astrophysics Data System (ADS)

Snedden, Stephanie A.; Gaskell, C. Martin

2007-11-01

A combined analysis of the profiles of the main broad quasar emission lines in both Hubble Space Telescope and optical spectra shows that while the profiles of the strong UV lines are quite similar, there is frequently a strong increase in the Lyα/Hα ratio in the high-velocity gas. We show that the suggestion that the high-velocity gas is optically thin presents many problems. We show that the relative strengths of the high-velocity wings arise naturally in an optically thick BLR component. An optically thick model successfully explains the equivalent widths of the lines, the Lyα/Hα ratios and flatter Balmer decrements in the line wings, the strengths of C III] and the λ1400 blend, and the strong variability in flux of high-velocity, high-ionization lines (especially He II and He I).

Neon and [CII] 158 μm Emission Line Profiles in Dusty Starbursts and Active Galactic Nuclei

NASA Astrophysics Data System (ADS)

Samsonyan, A.; Weedman, D.; Lebouteiller, V.; Barry, D.; Sargsyan, L.

2017-07-01

Identifying and understanding the initial formation of massive galaxies and quasars in the early universe is a fundamental goal of observational cosmology. A rapidly developing capability for tracing luminosity sources to high redshifts is the observation of the [CII] 158 μm emission line at redshifts z > 4 using ground based submillimeter interferometers, with detections now having been made to z = 7. This has long been known as the strongest far-infrared line in most sources, often carrying about 1% of the total source luminosity, and is thought to be associated with star formation because it should arise within the photodissociation region (PDR) surrounding starbursts. The sample of 382 extragalactic sources has been analysed that have mid-infrared,high resolution spectroscopy with the Spitzer Infrared Spectrograph (IRS) and also spectroscopy of the [CII] 158 μm line with the Herschel Photodetector Array Camera and Spectrometer (PACS). The emission line profiles of [NeII] 12.81μm , [NeIII] 15.55 μm , and [CII] 158 μm are studied, and intrinsic line widths are determined. All line profiles together with overlays comparing positions of PACS and IRS observations are made available in the Cornell Atlas of Spitzer IRS Sources (CASSIS). Sources are classified from AGN to starburst based on equivalent widths of the 6.2 μm polycyclic aromatic hydrocarbon feature. It is found that intrinsic line widths do not change among classification for [CII], with median widths of 207 km s-1 for AGN, 248 km s-1 for composites, and 233 km s-1 for starbursts. The [NeII] line widths also do not change with classification, but [NeIII] lines are progressively broader from starburst to AGN. A small number of objects with unusually broad lines or unusual redshift differences in any feature are identified.

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

NASA Technical Reports Server (NTRS)

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

1997-01-01

Our analysis of high-resolution Goddard High-Resolution Spectrograph (GHRS) spectra of late-type stars shows that the Si IV and C IV lines formed near 10(exp 5) K can be decomposed into the sum of two Gaussians, a broad component and a narrow component. We find that the flux contribution of the broad components is correlated with both the C IV and X-ray surface fluxes. For main-sequence stars, the widths of the narrow components suggest subsonic nonthermal velocities, and there appears to be a tight correlation between these nonthermal velocities and stellar surface gravity [xi(sub nc) varies as g(sup (-.68 +/-.07))]. For evolved stars with lower surface gravities, the nonthermal velocities suggested by the narrow components are at or just above the sound speed. Nonthermal velocities computed from the widths of the broad components are always highly supersonic. We propose that the broad components are diagnostics for microflare heating. Turbulent dissipation and Alfven waves are both viable candidates for the narrow component heating mechanism. A solar analog for the broad components might be the 'explosive events' detected by the High-Resolution Telescope and Spectrograph (HRTS) experiment. The broad component we observe for the Si IV lambda 1394 line of alpha Cen A, a star that is nearly identical to the Sun, has a FWHM of 109 +/- 10 km/s and is blueshifted by 9 +/- 3 km/s relative to the narrow component. Both of these properties are consistent with the properties of the solar explosive events. However, the alpha Cen A broad component accounts for 25% +/- 4% of the total Si IV line flux, while solar explosive events are currently thought to account for no more than 5% of the Sun's total transition region emission. This discrepancy must be resolved before the connection between broad components and explosive events can be positively established. In addition to our analysis of the Si IV and C IV lines of many stars, we also provide a more thorough analysis of all of the available GHRS data for alpha Cen A (G2 V) and alpha Cen B (K1 V). We find that the transition region lines of both stars have redshifts almost identical to those observed on the Sun: showing an increase with line formation temperature up to about log T = 5.2 and then a rapid decrease. Using the O IV] lines as density diagnostics, we compute electron densities of log n(sub e) = 9.65 +/- 0.20 and log n(sub e) = 9.50 +/- 0.30 for alpha Cen A and alpha Cen B, respectively.

The broad-band X-ray spectral variability of Mrk 841

NASA Technical Reports Server (NTRS)

George, I. M.; Nandra, K.; Fabian, A. C.; Turner, T. J.; Done, C.; Day, C. S. R.

1993-01-01

A detailed spectral analysis of five X-ray observations of Mrk 841 with the EXOSAT, Ginga, and ROSAT satellites is reported. Variability is apparent in both the soft (0.1-1.0 keV) and medium (1-20 keV) energy bands. Above, 1 keV, the spectra are adequately modeled by a power law with a strong emission line of equivalent width 450 eV. The large equivalent width of the emission line indicates a strongly enhanced reflection component of the source compared with other Seyferts observed with Ginga. The implications of the results of the analysis for physical models of the emission regions in this and other X-ray bright Seyferts are briefly examined.

Luminous clusters of Wolf-Rayet stars in the SBmIII galaxy NGC 4214

NASA Technical Reports Server (NTRS)

Sargent, Wallace L. W.; Filippenko, Alexei V.

1991-01-01

Observations are reported of strong broad emission lines attributed to WR stars in the spectra of several bright knots in the nearby Magellanic irregular galaxy NGC 4214 (classified as type SBmIII), in addition to the emission produced by the more prevalent WN stars). Data are presented on measurements of the line fluxes, the line equivalent widths, and continuum flux densities in the four observed knots, showing that the strongest WR lines generally appear in knots having the most luminous stellar continuum. The significance of this observation is discussed.

MOLECULAR GAS VELOCITY DISPERSIONS IN THE ANDROMEDA GALAXY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caldú-Primo, Anahi; Schruba, Andreas, E-mail: caldu@mpia.de, E-mail: schruba@mpe.mpg.de

In order to characterize the distribution of molecular gas in spiral galaxies, we study the line profiles of CO (1 – 0) emission in Andromeda, our nearest massive spiral galaxy. We compare observations performed with the IRAM 30 m single-dish telescope and with the CARMA interferometer at a common resolution of 23 arcsec ≈ 85 pc × 350 pc and 2.5 km s{sup −1}. When fitting a single Gaussian component to individual spectra, the line profile of the single dish data is a factor of 1.5 ± 0.4 larger than the interferometric data one. This ratio in line widths ismore » surprisingly similar to the ratios previously observed in two other nearby spirals, NGC 4736 and NGC 5055, but measured at ∼0.5–1 kpc spatial scale. In order to study the origin of the different line widths, we stack the individual spectra in five bins of increasing peak intensity and fit two Gaussian components to the stacked spectra. We find a unique narrow component of FWHM = 7.5 ± 0.4 km s{sup −1} visible in both the single dish and the interferometric data. In addition, a broad component with FWHM = 14.4 ± 1.5 km s{sup −1} is present in the single-dish data, but cannot be identified in the interferometric data. We interpret this additional broad line width component detected by the single dish as a low brightness molecular gas component that is extended on spatial scales >0.5 kpc, and thus filtered out by the interferometer. We search for evidence of line broadening by stellar feedback across a range of star formation rates but find no such evidence on ∼100 pc spatial scale when characterizing the line profile by a single Gaussian component.« less

The Solar Flare 4: 10 keV X-ray Spectrum

NASA Technical Reports Server (NTRS)

Phillips, K. J. H.

2004-01-01

The 4-10 keV solar flare spectrum includes highly excited lines of stripped Ca, Fe, and Ni ions as well as a continuum steeply falling with energy. Groups of lines at approximately 7 keV and approximately 8 keV, observed during flares by the broad-band RHESSI spectrometer and called here the Fe-line and Fe/Ni-line features, are formed mostly of Fe lines but with Ni lines contributing to the approximately 8 keV feature. Possible temperature indicators of these line features are discussed - the peak or centroid energies of the Fe-line feature, the line ratio of the Fe-line to the Fe/Ni-line features, and the equivalent width of the Fe-line feature. The equivalent width is by far the most sensitive to temperature. However, results will be confused if, as is commonly believed, the abundance of Fe varies from flare to flare, even during the course of a single flare. With temperature determined from the thermal continuum, the Fe-line feature becomes a diagnostic of the Fe abundance in flare plasmas. These results are of interest for other hot plasmas in coronal ionization equilibrium such as stellar flare plasmas, hot gas in galaxies, and older supernova remnants.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leighly, Karen M.; Cooper, Erin; Grupe, Dirk

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 reddeningmore » 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.« less

Variable broad lines and outflow in the weak blazar PBC J2333.9-2343

NASA Astrophysics Data System (ADS)

Hernández-García, L.; Vietri, G.; Panessa, F.; Piconcelli, E.; Chavushyan, V.; Jiménez-Andrade, E. F.; Bassani, L.; Bazzano, A.; Cazzoli, S.; Malizia, A.; Masetti, N.; Monaco, L.; Pović, M.; Saviane, I.; Ubertini, P.

2018-05-01

PBC J2333.9-2343 is a peculiar active nucleus with two giant radio lobes and a weak blazar-like nucleus at their center. In the present work we show new optical, UV, and X-ray data taken from the San Pedro Mártir telescope, the New Technology Telescope, NTT/EFOSC2, and the Swift/XRT satellite. The source is highly variable at all frequencies, in particular the strongest variations are found in the broad Hα component with a flux increase of 61±4 per cent between 2009 and 2016, following the X-ray flux increase of 62±6 per cent between 2010 and 2016. We also detected a broad Hβ component in 2016, making the optical classification change from type 1.9 to type 1.8 in one year. We have also detected a broad component of the [OIII]λ5007 line, which is blue-shifted and of high velocity, suggesting an origin from a highly disturbed medium, possibly an outflow. The line flux variability and broad widths are indicative of a jet that is, at least in part, responsible for the ionization of the BLR and NLR.

Broad-band properties of the CfA Seyfert galaxies. III - Ultraviolet variability

NASA Technical Reports Server (NTRS)

Edelson, R. A.; Pike, G. F.; Krolik, J. H.

1990-01-01

A total of 657 archived IUE spectra are used to study the UV variability properties of six members of the CfA Seyfert I galaxy sample. All show strong evidence for continuum and line variations and a tendency for less luminous objects to be more strongly variable. Most objects show a clear correlation at zero lag between UV spectral index and luminosity, evidence that the variable component is an accretion disk around a black hole which is systematically smaller in less luminous sources. No correlation is seen between the continuum luminosity and equivalent width of the C IV, Mg II, and semiforbidden C III emission lines when the entire sample is examined, but a clear anticorrelation is present when only repeated observations of individual objects are considered. This is due to a combination of light-travel time effects in the broad-line region and the nonlinear responses of lines to continuum fluctuations.

Sub-millimeter detected z ~ 2 radio-quiet QSOs. Accurate redshifts, black hole masses, and inflow/outflow velocities

NASA Astrophysics Data System (ADS)

Orellana, G.; Nagar, N. M.; Isaak, K. G.; Priddey, R.; Maiolino, R.; McMahon, R.; Marconi, A.; Oliva, E.

2011-07-01

Context. We present near-IR spectroscopy of a sample of luminous (MB - 27.5; Lbol > 1014 L⊙), sub-millimeter-detected, dusty (Md ~ 109 M⊙), radio-quiet quasi-stellar objects (QSOs) at z ~ 2. Aims: A primary aim is to provide a more accurate QSO redshift determination in order to trace kinematics and inflows/outflows in these sub-mm bright QSOs. Additionally, the Hα and continuum properties allow an estimation of the black hole mass and accretion rate, offering insights into the starburst-AGN connection in sub-mm bright QSOs. Methods: We measure the redshift, width, and luminosity of the Hα line, and the continuum luminosity near Hα. Relative velocity differences between Hα and rest-frame UV emission lines are used to study the presence and strength of outflows/inflows. Luminosities and line widths are used to estimate the black hole masses, bolometric luminosities, Eddington fractions, and accretion rates; these are compared to the star-formation-rate (SFR), estimated from the sub-mm derived far-infrared (FIR) luminosity. Finally our sub-mm-bright QSO sample is compared with other QSO samples at similar redshifts. Results: The Hα emission line was strongly detected in all sources. Two components - a very broad (≳5000 km s-1) Gaussian and an intermediate-width (≳1500 km s-1) Gaussian, were required to fit the Hα profile of all observed QSOs. Narrow (≲1000 km s-1) lines were not detected in the sample QSOs. The rest-frame UV emission lines in these sub-mm bright QSOs show larger than average blue-shifted velocities, potentially tracing strong - up to 3000 km s-1 - outflows in the broad line region. With the exception of the one QSO which shows exceptionally broad Hα lines, the black hole masses of the QSO sample are in the range log MBH = 9.0-9.7 and the Eddington fractions are between 0.5 and ~1. In black hole mass and accretion rate, this sub-mm bright QSO sample is indistinguishable from the Shemmer et al. (2004, ApJ, 614, 547) optically-bright QSO sample at z ~ 2; the latter is likely dominated by sub-mm dim QSOs. Previous authors have demonstrated a correlation, over six orders of magnitude, between SFR and accretion rate in active galaxies: the sub-mm bright QSOs lie at the upper extremes of both quantities and their SFR is an order of magnitude higher than that predicted from the correlation.

Investigating the reasons of variability in Si IV and C IV broad absorption line troughs of quasars

NASA Astrophysics Data System (ADS)

Stathopoulos, Dimitrios; Lyratzi, Evangelia; Danezis, Emmanuel; Antoniou, Antonios; Tzimeas, Dimitrios

2017-09-01

In this paper we analyze the C IV and Si IV broad absorption troughs of two BALQSOs (J101056.69+355833.3, J114548.38+393746.6) to the individual components they consist of. By analyzing a BAL trough to its components we have the advantage to study the variations of the individual absorbing systems in the line of sight and not just the variations of the whole absorption trough or the variations of selected portions of BAL troughs exhibiting changes. We find that the velocity shifts and FWHMs (Full Width at Half Maximum) of the individual components do not vary between an interval of six years. All variable components show changes in the optical depths at line centers which are manifested as variations in the EW (Equivalent Width) of the components. In both BALQSOs, over corresponding velocities, Si IV has higher incidence of variability than C IV. From our analysis, evidence is in favour of different covering fractions between C IV and Si IV. Finally, although most of our results favour the crossing cloud scenario as the cause of variability, there is also strong piece of evidence indicating changing ionization as the source of variability. Thus, a mixed situation where both physical mechanisms contribute to BAL variability is the most possible scenario.

Can we improve C IV-based single epoch black hole mass estimations?

NASA Astrophysics Data System (ADS)

Mejía-Restrepo, J. E.; Trakhtenbrot, B.; Lira, P.; Netzer, H.

2018-05-01

In large optical surveys at high redshifts (z > 2), the C IV broad emission line is the most practical alternative to estimate the mass (MBH) of active super-massive black holes (SMBHs). However, mass determinations obtained with this line are known to be highly uncertain. In this work we use the Sloan Digital Sky Survey Data Release 7 and 12 quasar catalogues to statistically test three alternative methods put forward in the literature to improve C IV-based MBH estimations. These methods are constructed from correlations between the ratio of the C IV line-width to the low ionization line-widths (Hα, Hβ and Mg II) and several other properties of rest-frame UV emission lines. Our analysis suggests that these correction methods are of limited applicability, mostly because all of them depend on correlations that are driven by the linewidth of the C IV profile itself and not by an interconnection between the linewidth of the C IV line with the linewidth of the low ionization lines. Our results show that optical C IV-based mass estimates at high redshift cannot be a proper replacement for estimates based on IR spectroscopy of low ionization lines like Hα, Hβ and Mg II.

Suppression of the Nonlinear Zeeman Effect and Heading Error in Earth-Field-Range Alkali-Vapor Magnetometers.

PubMed

Bao, Guzhi; Wickenbrock, Arne; Rochester, Simon; Zhang, Weiping; Budker, Dmitry

2018-01-19

The nonlinear Zeeman effect can induce splitting and asymmetries of magnetic-resonance lines in the geophysical magnetic-field range. This is a major source of "heading error" for scalar atomic magnetometers. We demonstrate a method to suppress the nonlinear Zeeman effect and heading error based on spin locking. In an all-optical synchronously pumped magnetometer with separate pump and probe beams, we apply a radio-frequency field which is in phase with the precessing magnetization. This results in the collapse of the multicomponent asymmetric magnetic-resonance line with ∼100  Hz width in the Earth-field range into a single peak with a width of 22 Hz, whose position is largely independent of the orientation of the sensor within a range of orientation angles. The technique is expected to be broadly applicable in practical magnetometry, potentially boosting the sensitivity and accuracy of Earth-surveying magnetometers by increasing the magnetic-resonance amplitude, decreasing its width, and removing the important and limiting heading-error systematic.

Investigating the Luminous Environment of SDSS Data Release 4 Mg II Absorption Line Systems

NASA Astrophysics Data System (ADS)

Caler, Michelle A.; Ravi, Sheth K.

2018-01-01

We investigate the luminous environment within a few hundred kiloparsecs of 3760 Mg II absorption line systems. These systems lie along 3760 lines of sight to Sloan Digital Sky Survey (SDSS) Data Release 4 QSOs, have redshifts that range between 0.37 ≤ z ≤ 0.82, and have rest equivalent widths greater than 0.18 Å. We use the SDSS Catalog Archive Server to identify galaxies projected near 3 arcminutes of the absorbing QSO’s position, and a background subtraction technique to estimate the absolute magnitude distribution and luminosity function of galaxies physically associated with these Mg II absorption line systems. The Mg II absorption system sample is split into two parts, with the split occurring at rest equivalent width 0.8 Å, and the resulting absolute magnitude distributions and luminosity functions compared on scales ranging from 50 h-1 kpc to 880 h-1 kpc. We find that, on scales of 100 h-1 kpc and smaller, the two distributions differ: the absolute magnitude distribution of galaxies associated with systems of rest frame equivalent width ≥ 0.8 Å (2750 lines of sight) seems to be approximated by that of elliptical-Sa type galaxies, whereas the absolute magnitude distribution of galaxies associated with systems of rest frame equivalent width < 0.8 Å (1010 lines of sight) seems to be approximated by that of Sa-Sbc type galaxies. However, on larger scales greater than 200 h-1 kpc, both distributions are broadly consistent with that of elliptical-Sa type galaxies. We note that, in a broader context, these results represent an estimate of the bright end of the galaxy luminosity function at a median redshift of z ˜ 0.65.

No Compton Reflection In a Chandra/RXTE Observation of Mkn 509: Implications for the Fe-K Line Emission From Accreting X-Ray Sources

NASA Technical Reports Server (NTRS)

Yaqoob, Tahir; Padmanabhan, Urmila; Kraemer, Steven B.; Crenshaw, D. Michael; Mckernan, Barry; George, Ian M.; Turner, T. Jane; White, Nicholas E. (Technical Monitor)

2002-01-01

We report the results of simultaneous Chandra and RXTE observations of the Seyfert 1 galaxy Mkn 509. We deconvolve the broad and narrow Fe-K emission-line components for which we measure rest-frame equivalent widths of 119+/-18 eV and 57+/-13 eV respectively. The broad line has a FWHM of 57,600((sup 14,400)(sub -21,000)) km/s and the narrow line is unresolved, with an upper limit on the FWHM of 4,940 km/s. Both components must originate in cool matter since we measure rest-frame center energies of 6.36((sup +0.13)(sub -0.12)) keV and 6.42+/-0.01 keV for the broad and narrow line respectively. This rules out He-like and H-like Fe for the origin of both the broad and narrow lines. If, as is widely accepted, the broad Fe-K line originates in Thomson-thick matter (such as an accretion disk), then one expects to observe spectral curvature above approximately 10 keV, (commensurate with the observed broad line), characteristic of the Compton-reflection continuum. However our data sets very stringent limits on deviations of the observed continuum from a power law. Light travel-time delays cannot be invoked to explain anomalies in the relative strengths of the broad Ferry line and Compton-reflection continuum since they are supposed to originate in the same physical location. We are forced to conclude that both the broad and narrow Fe-K lines had to originate in Thomson-thin matter during our observation. This result, for a single observation of just one source, means that our understanding of Fe K line emission and Compton reflection from accreting X-ray sources in general needs to be re-examined. For example, if an irradiated accretion disk existed in Mkn 509 at the time of the observations, the lack of spectral curvature above approximately 10 keV suggests two possibilities. Either the disk was Thomson-thick and highly ionized, having negligible Fe-K line emission and photoelectric absorption or the disk was Thomson-thin producing some or all of the broad Fe-K line emission. In the former case, the broad Fe-K line had to have produced in a Thomson-thin region elsewhere. In both cases the predicted spectral curvature above approximately 10 keV is negligible. An additional implication of our results is that any putative obscuring torus in the system, required by unification models of active galaxies, must also be Thomson-thin. The same applies to the optical broad line region (BLR) if it has a substantial covering factor.

Integral Field Spectroscopy of Balmer-dominated Shocks in the Magellanic Cloud Supernova Remnant N103B

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghavamian, Parviz; Seitenzahl, Ivo R.; Dopita, M. A.

2017-10-01

We present results of integral field spectroscopy of Balmer-dominated shocks in the LMC supernova remnant (SNR) N103B, carried out using the Wide Field Integral Spectrograph (WiFeS ) on the 2.3 m telescope at the Siding Spring Observatory in Australia. Existing X-ray studies of N103B have indicated an SN Ia origin. Radiative shock emission from clumpy material surrounding the SNR may result from interaction of the forward shock with relic stellar wind material, possibly implicating a thermonuclear explosion in a single-degenerate binary system. The recently discovered Balmer-dominated shocks mark the impact of the forward shock with low density, partially neutral CSMmore » gas, and form a partial shell encircling clumps of material exhibiting radiative shocks. The WiFeS spectra of N103B reveal broad H α emission having a width as high as 2350 km s{sup −1} along the northern rim, and both H α and H β broad profiles having widths around 1300 km s{sup −1} along the southern rim. Fits to the H α line profiles indicate that in addition to the usual broad and narrow emission components, a third component of intermediate width exists in these Balmer-dominated shocks, ranging from around 125 km s{sup −1} up to 225 km s{sup −1} in width. This is consistent with predictions of recent Balmer-dominated shock models, which predict that an intermediate-width component will be generated in a fast neutral precursor. We derive a Sedov age of approximately 685 ± 20 years for N103B from the Balmer-dominated spectra, consistent with the young age of 380–860 years estimated from light echo studies.« less

Electron spin resonance of particulate soot samples from automobiles to help environmental studies.

PubMed

Yamanaka, C; Matsuda, T; Ikeya, M

2005-02-01

The application of electron spin resonance (ESR) was studied for diesel soot samples and suspended particulate matter (SPM) from automobile engines. Soot samples or diesel exhaust particles (DEP) were recovered at various points: in the exhaust pipe of a diesel engine, at the dust sampler of a highway tunnel (standard DEP), on the soundproofing wall alongside a heavy traffic road, and on the filters of a dust sampler for SPM. The diesel soot samples apparently showed two ESR spectra: one was a broad spectrum at g=2.1 with a line width of ca. 80-120 mT and the other was a sharp signal of a carbon radical at g=2.003 with a line width of 0.4 mT. Annealing experiments with a DEP sample at 250 degrees C revealed drastic enhancement of the sharp ESR signal, which suggested a thermal process of carbonization of remnant organics. An oximetric study by ESR showed an enhancement of the broad signal in the diesel soot sample as well as in the sharp ESR signal. Therefore, the main part of the broad ESR signal would be attributed to carbon radicals, which form a different configuration, probably closely interacting aggregates. Enhancement of the sharp ESR signal was not observed in the standard DEP sample under vacuum condition, which suggested less adsorption sites on the surface of DEP samples.

Studies on 405nm blue-violet diode laser with external grating cavity

NASA Astrophysics Data System (ADS)

Li, Bin; Gao, Jun; Zhao, Jun; Yu, Anlan; Luo, Shiwen; Xiong, Dongsheng; Wang, Xinbing; Zuo, Duluo

2016-03-01

Spectroscopy applications of free-running laser diodes (LD) are greatly restricted as its broad band spectral emission. And the power of a single blue-violet LD is around several hundred milliwatts by far, it is of great importance to obtain stable and narrow line-width laser diodes with high efficiency. In this paper, a high efficiency external cavity diode laser (ECDL) with high output power and narrow band emission at 405 nm is presented. The ECDL is based on a commercially available LD with nominal output power of 110 mW at an injection current of 100 mA. The spectral width of the free-running LD is about 1 nm (FWHM). A reflective holographic grating which is installed on a home-made compact adjustable stage is utilized for optical feedback in Littrow configuration. In this configuration, narrow line-width operation is realized and the effects of grating groove density as well as the groove direction related to the beam polarization on the performances of the ECDL are experimentally investigated. In the case of grating with groove density of 3600 g/mm, the threshold is reduced from 21 mA to 18.3 mA or 15.6 mA and the tuning range is 3.95 nm or 6.01 nm respectively when the grating is orientated in TE or TM polarization. In addition, an output beam with a line-width of 30 pm and output power of 92.7 mW is achieved in TE polarization. With these narrow line-width and high efficiency, the ECDL is capable to serve as a light source for spectroscopy application such as Raman scattering and laser induced fluorescence.

Broad Halpha Wing Formation in the Planetary Nebula IC 4997.

PubMed

Lee; Hyung

2000-02-10

The young and compact planetary nebula IC 4997 is known to exhibit very broad wings with a width exceeding 5000 km s-1 around Halpha. We propose that the broad wings are formed through Rayleigh-Raman scattering that involves atomic hydrogen, by which Lybeta photons with a velocity width of a few 102 km s-1 are converted to optical photons and fill the Halpha broad wing region. The conversion efficiency reaches 0.6 near the line center, where the scattering optical depth is much larger than 1, and rapidly decreases in the far wings. Assuming that close to the central star there exists an unresolved inner compact core of high density, nH approximately 109-1010 cm-3, we use the photoionization code "CLOUDY" to show that sufficient Lybeta photons for scattering are produced. Using a top-hat-incident profile for the Lybeta flux and a scattering region with a H i column density NHi=2x1020 cm-2 and a substantial covering factor, we perform a profile-fitting analysis in order to obtain a satisfactory fit to the observed flux. We briefly discuss the astrophysical implications of the Rayleigh-Raman processes in planetary nebulae and other emission objects.

The nebular spectra of the transitional Type Ia Supernovae 2007on and 2011iv: broad, multiple components indicate aspherical explosion cores

NASA Astrophysics Data System (ADS)

Mazzali, P. A.; Ashall, C.; Pian, E.; Stritzinger, M. D.; Gall, C.; Phillips, M. M.; Höflich, P.; Hsiao, E.

2018-05-01

The nebular-epoch spectrum of the rapidly declining, `transitional' Type Ia supernova (SN) 2007on showed double emission peaks, which have been interpreted as indicating that the SN was the result of the direct collision of two white dwarfs. The spectrum can be reproduced using two distinct emission components, one redshifted and one blueshifted. These components are similar in mass but have slightly different degrees of ionization. They recede from one another at a line-of-sight speed larger than the sum of the combined expansion velocities of their emitting cores, thereby acting as two independent nebulae. While this configuration appears to be consistent with the scenario of two white dwarfs colliding, it may also indicate an off-centre delayed detonation explosion of a near-Chandrasekhar-mass white dwarf. In either case, broad emission line widths and a rapidly evolving light curve can be expected for the bolometric luminosity of the SN. This is the case for both SNe 2007on and 2011iv, also a transitional SN Ia that exploded in the same elliptical galaxy, NGC 1404. Although SN 2011iv does not show double-peaked emission line profiles, the width of its emission lines is such that a two-component model yields somewhat better results than a single-component model. Most of the mass ejected is in one component, however, which suggests that SN 2011iv was the result of the off-centre ignition of a Chandrasekhar-mass white dwarf.

VizieR Online Data Catalog: BAL QSOs from SDSS DR3 (Trump+, 2006)

NASA Astrophysics Data System (ADS)

Trump, J. R.; Hall, P. B.; Reichard, T. A.; Richards, G. T.; Schneider, D. P.; vanden Berk, D. E.; Knapp, G. R.; Anderson, S. F.; Fan, X.; Brinkman, J.; Kleinman, S. J.; Nitta, A.

2007-11-01

We present a total of 4784 unique broad absorption line quasars from the Sloan Digital Sky Survey Third Data Release (Cat. ). An automated algorithm was used to match a continuum to each quasar and to identify regions of flux at least 10% below the continuum over a velocity range of at least 1000km/s in the CIV and MgII absorption regions. The model continuum was selected as the best-fit match from a set of template quasar spectra binned in luminosity, emission line width, and redshift, with the power-law spectral index and amount of dust reddening as additional free parameters. We characterize our sample through the traditional balnicity index and a revised absorption index, as well as through parameters such as the width, outflow velocity, fractional depth, and number of troughs. (1 data file).

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

NASA Astrophysics Data System (ADS)

Gaskell, C. Martin; Goosmann, René W.

2016-02-01

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

Baldwin Effect and Additional BLR Component in AGN with Superluminal Jets

NASA Astrophysics Data System (ADS)

Patiño Álvarez, Víctor; Torrealba, Janet; Chavushyan, Vahram; Cruz González, Irene; Arshakian, Tigran; León Tavares, Jonathan; Popovic, Luka

2016-06-01

We study the Baldwin Effect (BE) in 96 core-jet blazars with optical and ultraviolet spectroscopic data from a radio-loud AGN sample obtained from the MOJAVE 2cm survey. A statistical analysis is presented of the equivalent widths W_lambda of emission lines H beta 4861, Mg II 2798, C IV 1549, and continuum luminosities at 5100, 3000, and 1350 angstroms. The BE is found statistically significant (with confidence level c.l. > 95%) in H beta and C IV emission lines, while for Mg II the trend is slightly less significant (c.l. = 94.5%). The slopes of the BE in the studied samples for H beta and Mg II are found steeper and with statistically significant difference than those of a comparison radio-quiet sample. We present simulations of the expected BE slopes produced by the contribution to the total continuum of the non-thermal boosted emission from the relativistic jet, and by variability of the continuum components. We find that the slopes of the BE between radio-quiet and radio-loud AGN should not be different, under the assumption that the broad line is only being emitted by the canonical broad line region around the black hole. We discuss that the BE slope steepening in radio AGN is due to a jet associated broad-line region.

The photoionization mechanism of LINERs - Stellar and nonstellar

NASA Technical Reports Server (NTRS)

Ho, Luis C.; Filippenko, Alexei V.

1993-01-01

We present high quality spectroscopic observations of a sample of 14 LINERs. Starlight removal is achieved by the subtraction of a suitable absorption-line 'template' galaxy, allowing accurate measurements of emission lines. We use these line fluxes to examine the possible excitation mechanisms of LINERs. We suggest that LINERs with weak forbidden O I 6300-A emission may be H II regions photoionized by unusually hot O-type stars. LINERs with forbidden O I/H-alpha approximately greater than 1/6 may be powered by photoionization from a nonstellar continuum. This is supported by the detection of broad H-alpha emission, a correlation between line width and critical density, and pointlike X-ray emission in several of these objects.

The Cambridge-Cambridge x-ray serendipity survey. 2: Classification of x-ray luminous galaxies

NASA Technical Reports Server (NTRS)

Boyle, B. J.; Mcmahon, R. G.; Wilkes, B. J.; Elvis, Martin

1994-01-01

We present the results of an intermediate-resolution (1.5 A) spectroscopic study of 17 x-ray luminous narrow emission-line galaxies previously identified in the Cambridge-Cambridge ROSAT Serendipity Survey and the Einstein Extended Medium Sensitivity Survey. Emission-line ratios reveal that the sample is composed of ten Seyfert and seven starburst galaxies. Measured linewidths for the narrow H alpha emission lines lie in the range 170 - 460 km s(exp -1). Five of the objects show clear evidence for asymmetry in the (OIII) lambda 5007 emission-line profile. Broad H alpha emission is detected in six of the Seyfert galaxies, which range in type from Seyfert 1.5 to 2. Broad H beta emission is only detected in one Seyfert galaxy. The mean full width at half maximum for the broad lines in the Seyfert galaxies is FWHM = 3900 +/- 1750 km s(exp -1). Broad (FWHM = 2200 +/- 600 km s(exp -1) H alpha emission is also detected in three of the starburst galaxies, which could originate from stellar winds or supernovae remnants. The mean Balmer decrement for the sample is H alpha / H beta = 3, consistent with little or no reddening for the bulk of the sample. There is no evidence for any trend with x-ray luminosity in the ratio of starburst galaxies to Seyfert galaxies. Based on our previous observations, it is therefore likely that both classes of object comprise approximately 10 percent of the 2 keV x-ray background.

Weak Emission-line Quasars in the Context of a Modified Baldwin Effect

NASA Astrophysics Data System (ADS)

Shemmer, Ohad

2016-01-01

Based on spectroscopic data for a sample of high-redshift quasars, I will show that the anti-correlation between the rest-frame equivalent width (EW) of the C IV λ1549 broad-emission line and the Hβ-based Eddington ratio extends across the widest possible ranges of redshift (0 < z < 3.5) and bolometric luminosity(~1044 < L < ~1048 erg s-1). Given this anti-correlation, hereby referred to as a modified Baldwin effect (MBE), weak emission line quasars (WLQs), typically showing EW(C IV) < ~10 Å, are expected to have extremely high Eddington ratios (L/LEdd > ~4). I will present new near-infrared spectroscopy of the broad Hβ line, as well as complementary EW(C IV) information, for all WLQs for which such information is currently available, nine sources in total. I will show that while four of these WLQs can be accommodated by the MBE, the otherfive deviate significantly from this relation, at the > ~3σ level, by exhibiting C IV lines much weaker than predicted from their Hβ-based Eddington ratios. Assuming the supermassive black hole masses in all quasars can be determined reliably using the single-epoch Hβ-method, these results indicate that EW(C IV)cannot depend solely on the Eddington ratio. I will briefly discuss a strategy for further investigation into the roles that basic physical properties play in controlling the relative strengths of broad-emission lines in quasars.

Strong optical and UV intermediate-width emission lines in the quasar SDSS J232444.80-094600.3: dust-free and intermediate-density gas at the skin of dusty torus?

NASA Astrophysics Data System (ADS)

Li, Zhen-Zhen; Zhou, Hong-Yan; Hao, Lei; Wang, Shu-Fen; Ji, Tuo; Liu, Bo

2016-09-01

Emission lines from the broad emission line region (BELR) and the narrow emission line region (NELR) of active galactic nuclei (AGNs) have been extensively studied. However, emission lines are rarely detected between these two regions. We present a detailed analysis of quasar SDSS J232444.80-094600.3 (SDSS J2324-0946), which is remarkable for its strong intermediate-width emission lines (IELs) with FWHM ≈ 1800 km s-1. The IEL component is present in different emission lines, including the permitted lines Lyα λ1216, CIV λ1549, semiforbidden line [CIII] λ1909, and forbidden lines [OIII] λλ4959, 5007. With the aid of photo-ionization models, we found that the IELs are produced by gas with a hydrogen density of nH ˜ 106.2 ˜ 106.3 cm-3, a distance from the central ionizing source of R ˜ 35 - 50 pc, a covering factor of ˜ 6%, and a dust-to-gas ratio of ≤ 4% that of the SMC. We suggest that the strong IELs of this quasar are produced by nearly dust-free and intermediate-density gas located at the skin of the dusty torus. Such strong IELs, which serve as a useful diagnostic, can provide an avenue to study the properties of gas between the BELR and the NELR.

C IV λ1549 as an Eigenvector 1 Parameter for Active Galactic Nuclei

NASA Astrophysics Data System (ADS)

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

2007-09-01

We are exploring a spectroscopic unification for all types of broad-line emitting AGNs. The four-dimensional Eigenvector 1 (4DE1) parameter space organizes quasar diversity in a sequence primarily governed by Eddington ratio. This paper considers the role of C IV λ1549 measures as 4DE1 diagnostics. We use HST archival spectra for 130 sources with S/N high enough to permit reliable C IV λ1549 broad-component measures. We find a C IV λ1549BC profile blueshift that is strongly concentrated among (largely radio-quiet [RQ]) sources with FWHM(HβBC)<~4000 km s-1 (which we call Population A). Narrow-line Seyfert 1 (NLSy1; with FWHM Hβ<=2000 km s-1) sources belong to this population but do not emerge as a distinct class. The systematic blueshift, widely interpreted as arising in a disk wind/outflow, is not observed in broader line AGNs (including most radio-loud [RL] sources), which we call Population B. We find new correlations involving FWHM(C IV λ1549BC), C IV λ1549 line shift, and equivalent width only among Population A sources. Sulentic et al. suggested C IV λ1549 measures enhance an apparent dichotomy between sources with FWHM(HβBC) less and greater than 4000 km s-1, suggesting that it has more significance in the context of broad-line region structure than the more commonly discussed RL versus RQ dichotomy. Black hole masses computed from FWHM C IV λ1549BC for about 80 AGNs indicate that the C IV λ1549 width is a poor virial estimator. Comparison of mass estimates derived from HβBC and C IV λ1549 reveals that the latter show different and nonlinear offsets for Population A and B sources. A significant number of sources also show narrow-line C IV λ1549 emission that must be removed before C IV λ1549BC measures can be made and interpreted effectively. We present a recipe for C IV λ1549 narrow-component extraction.

A Reverberation-based Black Hole Mass for MCG-06-30-15

NASA Astrophysics Data System (ADS)

Bentz, Misty C.; Cackett, Edward M.; Crenshaw, D. Michael; Horne, Keith; Street, Rachel; Ou-Yang, Benjamin

2016-10-01

We present the results of a reverberation campaign targeting MGC-06-30-15. Spectrophotometric monitoring and broad-band photometric monitoring over the course of four months in spring 2012 allowed a determination of a time delay in the broad Hβ emission line of τ = 5.3 ± 1.8 days in the rest frame of the active galactic nucleus (AGN). Combined with the width of the variable portion of the emission line, we determine a black hole mass of M BH = (1.6 ± 0.4) × 106 M ⊙. Both the Hβ time delay and the black hole mass are in good agreement with expectations from the R BLR-L and M BH-σ ⋆ relationships for other reverberation-mapped AGNs. The Hβ time delay is also in good agreement with the relationship between Hβ and broad-band near-IR delays, in which the effective size of the broad-line region is ˜4-5 times smaller than the inner edge of the dust torus. Additionally, the reverberation-based mass is in good agreement with estimates from the scaling relationship of the break in the X-ray power spectral density, and with constraints based on stellar kinematics derived from integral field spectroscopy of the inner ˜0.5 kpc of the galaxy.

Using the Properties of Broad Absorption Line Quasars to Illuminate Quasar Structure

NASA Astrophysics Data System (ADS)

Yong, Suk Yee; King, Anthea L.; Webster, Rachel L.; Bate, Nicholas F.; O'Dowd, Matthew J.; Labrie, Kathleen

2018-06-01

A key to understanding quasar unification paradigms is the emission properties of broad absorption line quasars (BALQs). The fact that only a small fraction of quasar spectra exhibit deep absorption troughs blueward of the broad permitted emission lines provides a crucial clue to the structure of quasar emitting regions. To learn whether it is possible to discriminate between the BALQ and non-BALQ populations given the observed spectral properties of a quasar, we employ two approaches: one based on statistical methods and the other supervised machine learning classification, applied to quasar samples from the Sloan Digital Sky Survey. The features explored include continuum and emission line properties, in particular the absolute magnitude, redshift, spectral index, line width, asymmetry, strength, and relative velocity offsets of high-ionisation C IV λ1549 and low-ionisation Mg II λ2798 lines. We consider a complete population of quasars, and assume that the statistical distributions of properties represent all angles where the quasar is viewed without obscuration. The distributions of the BALQ and non-BALQ sample properties show few significant differences. None of the observed continuum and emission line features are capable of differentiating between the two samples. Most published narrow disk-wind models are inconsistent with these observations, and an alternative disk-wind model is proposed. The key feature of the proposed model is a disk-wind filling a wide opening angle with multiple radial streams of dense clumps.

Broad Feshbach resonance in the 6Li-40K mixture.

PubMed

Tiecke, T G; Goosen, M R; Ludewig, A; Gensemer, S D; Kraft, S; Kokkelmans, S J J M F; Walraven, J T M

2010-02-05

We study the widths of interspecies Feshbach resonances in a mixture of the fermionic quantum gases 6Li and 40K. We develop a model to calculate the width and position of all available Feshbach resonances for a system. Using the model, we select the optimal resonance to study the {6}Li/{40}K mixture. Experimentally, we obtain the asymmetric Fano line shape of the interspecies elastic cross section by measuring the distillation rate of 6Li atoms from a potassium-rich 6Li/{40}K mixture as a function of magnetic field. This provides us with the first experimental determination of the width of a resonance in this mixture, DeltaB=1.5(5) G. Our results offer good perspectives for the observation of universal crossover physics using this mass-imbalanced fermionic mixture.

A Multiwavelength Study of POX 52, a Dwarf Seyfert Galaxy with an Intermediate Mass Black Hole

NASA Astrophysics Data System (ADS)

Barth, Aaron

2004-09-01

POX 52 is a Seyfert 1 galaxy with unprecedented properties: its host galaxy is a dwarf elliptical, and its stellar velocity dispersion is only 36 km/s. The stellar velocity dispersion and the broad emission-line widths both suggest a black hole mass of order 10^5 solar masses. We request HST ACS/HRC imaging to perform a definitive measurement of the host galaxy structure; STIS UV and optical spectroscopy to study the nonstellar continuum and the structure of the broad-line region; and Chandra ACIS imaging to investigate the spectral and variability properties of the X-ray emission. The results of this program will give a detailed understanding of the host galaxy and accretion properties of one of the very few known black holes in the mass range around 10^5 solar masses.

THE SLOAN DIGITAL SKY SURVEY REVERBERATION MAPPING PROJECT: RAPID C iv BROAD ABSORPTION LINE VARIABILITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grier, C. J.; Brandt, W. N.; Trump, J. R.

2015-06-10

We report the discovery of rapid variations of a high-velocity C iv broad absorption line trough in the quasar SDSS J141007.74+541203.3. This object was intensively observed in 2014 as a part of the Sloan Digital Sky Survey Reverberation Mapping Project, during which 32 epochs of spectroscopy were obtained with the Baryon Oscillation Spectroscopic Survey spectrograph. We observe significant (>4σ) variability in the equivalent width (EW) of the broad (∼4000 km s{sup −1} wide) C iv trough on rest-frame timescales as short as 1.20 days (∼29 hr), the shortest broad absorption line variability timescale yet reported. The EW varied by ∼10%more » on these short timescales, and by about a factor of two over the duration of the campaign. We evaluate several potential causes of the variability, concluding that the most likely cause is a rapid response to changes in the incident ionizing continuum. If the outflow is at a radius where the recombination rate is higher than the ionization rate, the timescale of variability places a lower limit on the density of the absorbing gas of n{sub e} ≳ 3.9 × 10{sup 5} cm{sup −3}. The broad absorption line variability characteristics of this quasar are consistent with those observed in previous studies of quasars, indicating that such short-term variability may in fact be common and thus can be used to learn about outflow characteristics and contributions to quasar/host-galaxy feedback scenarios.« less

No evidence for Lyman α emission in spectroscopy of z > 7 candidate galaxies

NASA Astrophysics Data System (ADS)

Caruana, Joseph; Bunker, Andrew J.; Wilkins, Stephen M.; Stanway, Elizabeth R.; Lacy, Mark; Jarvis, Matt J.; Lorenzoni, Silvio; Hickey, Samantha

2012-12-01

We present Gemini/Gemini Near Infrared Spectrograph (GNIRS) spectroscopic observations of four z-band (z ≈ 7) dropout galaxies and Very Large Telescope (VLT)/XSHOOTER observations of one z-band dropout and three Y-band (z ≈ 8-9) dropout galaxies in the Hubble Ultra Deep Field, which were selected with Wide Field Camera 3 imaging on the Hubble Space Telescope. We find no evidence of Lyman α emission with a typical 5σ sensitivity of 5 × 10-18 erg cm-2 s-1, and use the upper limits on Lyman α flux and the broad-band magnitudes to constrain the rest-frame equivalent widths for this line emission. Accounting for incomplete spectral coverage, we survey 3.0 z-band dropouts and 2.9 Y-band dropouts to a Lyman α rest-frame equivalent width limit >120 Å (for an unresolved emission line); for an equivalent width limit of 50 Å the effective numbers of drop-outs surveyed fall to 1.2 z-band drop-outs and 1.5 Y-band drop-outs. A simple model where the fraction of high rest-frame equivalent width emitters follows the trend seen at z = 3-6.5 is inconsistent with our non-detections at z = 7-9 at the ≈1σ level for spectrally unresolved lines, which may indicate that a significant neutral H I fraction in the intergalactic medium suppresses the Lyman α line in z-drop and Y-drop galaxies at z > 7. Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere, Chile, as part of programme 086.A-0968(B).

Optical Variability of Narrow-line and Broad-line Seyfert 1 Galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rakshit, Suvendu; Stalin, C. S., E-mail: suvenduat@gmail.com

We studied the optical variability (OV) of a large sample of narrow-line Seyfert 1 (NLSy1) and broad-line Seyfert 1 (BLSy1) galaxies with z < 0.8 to investigate any differences in their OV properties. Using archival optical V -band light curves from the Catalina Real Time Transient Survey that span 5–9 years and modeling them using damped random walk, we estimated the amplitude of variability. We found that NLSy1 galaxies as a class show lower amplitude of variability than their broad-line counterparts. In the sample of both NLSy1 and BLSy1 galaxies, radio-loud sources are found to have higher variability amplitude thanmore » radio-quiet sources. Considering only sources that are detected in the X-ray band, NLSy1 galaxies are less optically variable than BLSy1 galaxies. The amplitude of variability in the sample of both NLSy1 and BLSy1 galaxies is found to be anti-correlated with Fe ii strength but correlated with the width of the H β line. The well-known anti-correlation of variability–luminosity and the variability–Eddington ratio is present in our data. Among the radio-loud sample, variability amplitude is found to be correlated with radio-loudness and radio-power, suggesting that jets also play an important role in the OV in radio-loud objects, in addition to the Eddington ratio, which is the main driving factor of OV in radio-quiet sources.« less

Optical Variability of Narrow-line and Broad-line Seyfert 1 Galaxies

NASA Astrophysics Data System (ADS)

Rakshit, Suvendu; Stalin, C. S.

2017-06-01

We studied the optical variability (OV) of a large sample of narrow-line Seyfert 1 (NLSy1) and broad-line Seyfert 1 (BLSy1) galaxies with z < 0.8 to investigate any differences in their OV properties. Using archival optical V-band light curves from the Catalina Real Time Transient Survey that span 5-9 years and modeling them using damped random walk, we estimated the amplitude of variability. We found that NLSy1 galaxies as a class show lower amplitude of variability than their broad-line counterparts. In the sample of both NLSy1 and BLSy1 galaxies, radio-loud sources are found to have higher variability amplitude than radio-quiet sources. Considering only sources that are detected in the X-ray band, NLSy1 galaxies are less optically variable than BLSy1 galaxies. The amplitude of variability in the sample of both NLSy1 and BLSy1 galaxies is found to be anti-correlated with Fe II strength but correlated with the width of the Hβ line. The well-known anti-correlation of variability-luminosity and the variability-Eddington ratio is present in our data. Among the radio-loud sample, variability amplitude is found to be correlated with radio-loudness and radio-power, suggesting that jets also play an important role in the OV in radio-loud objects, in addition to the Eddington ratio, which is the main driving factor of OV in radio-quiet sources.

Self-shadowing effects of slim accretion disks in active galactic nuclei: the diverse appearance of the broad-line region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jian-Min; Qiu, Jie; Du, Pu

2014-12-10

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

Circumnuclear star formation in Mrk 42 mapped with Gemini Near-infrared Integral Field Spectrograph

NASA Astrophysics Data System (ADS)

Hennig, Moiré G.; Riffel, Rogemar A.; Dors, O. L.; Riffel, Rogerio; Storchi-Bergmann, Thaisa; Colina, Luis

2018-06-01

We present Gemini Near-infrared Integral Field Spectrograph (NIFS) observations of the inner 1.5 × 1.5 kpc2 of the narrow-line Seyfert 1 galaxy Mrk 42 at a spatial resolution of 60 pc and spectral resolution of 40 km s^{-1}. The emission-line flux and equivalent width maps clearly show a ring of circumnuclear star formation regions surrounding the nucleus with radius of ˜500 pc. The spectra of some of these regions show molecular absorption features which are probably of CN, TiO, or VO, indicating the presence of massive evolved stars in the thermally pulsing asymptotic giant branch phase. The gas kinematics of the ring is dominated by rotation in the plane of the galaxy, following the large-scale disc geometry, while at the nucleus an additional outflowing component is detected blueshifted by 300-500 km s^{-1}, relative to the systemic velocity of the galaxy. Based on the equivalent width of Br γ we find pieces of evidence of gradients in the age of H II regions along the ring of Mrk 42, favouring the pearls on a string scenario of star formation. The broad component of Pa β emission line presents a Full Width at Half Maximum of ˜1480 km s^{-1}, implying in a mass of ˜2.5 × 106 M⊙ for the central supermassive black hole. Based on emission-line ratios we conclude that besides the active galactic nucleus, Mrk 42 presents nuclear Starburst activity.

A REVERBERATION-BASED BLACK HOLE MASS FOR MCG-06-30-15

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bentz, Misty C.; Crenshaw, D. Michael; Ou-Yang, Benjamin

2016-10-20

We present the results of a reverberation campaign targeting MGC-06-30-15. Spectrophotometric monitoring and broad-band photometric monitoring over the course of four months in spring 2012 allowed a determination of a time delay in the broad H β emission line of τ = 5.3 ± 1.8 days in the rest frame of the active galactic nucleus (AGN). Combined with the width of the variable portion of the emission line, we determine a black hole mass of M {sub BH} = (1.6 ± 0.4) × 10{sup 6} M {sub ⊙}. Both the H β time delay and the black hole mass aremore » in good agreement with expectations from the R {sub BLR}– L and M {sub BH}– σ {sub ⋆} relationships for other reverberation-mapped AGNs. The H β time delay is also in good agreement with the relationship between H β and broad-band near-IR delays, in which the effective size of the broad-line region is ∼4–5 times smaller than the inner edge of the dust torus. Additionally, the reverberation-based mass is in good agreement with estimates from the scaling relationship of the break in the X-ray power spectral density, and with constraints based on stellar kinematics derived from integral field spectroscopy of the inner ∼0.5 kpc of the galaxy.« less

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

NASA Technical Reports Server (NTRS)

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

2009-01-01

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

SUZAKU MONITORING OF THE IRON K EMISSION LINE IN THE TYPE 1 ACTIVE GALACTIC NUCLEUS NGC 5548

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu Yuan; Elvis, Martin; Wilkes, Belinda J.

2010-02-20

We present seven sequential weekly observations of NGC 5548 conducted in 2007 with the Suzaku X-ray Imaging Spectrometer (XIS) in the 0.2-12 keV band and Hard X-ray Detector (HXD) in the 10-600 keV band. The iron Kalpha line is well detected in all seven observations and Kbeta line is also detected in four observations. In this paper, we investigate the origin of the Fe K lines using both the width of the line and the reverberation mapping method. With the co-added XIS and HXD spectra, we identify Fe Kalpha and Kbeta line at 6.396{sup +0.009}{sub -0.007} keV and 7.08{sup +0.05}{submore » -0.05} keV, respectively. The width of line obtained from the co-added spectra is 38{sup +16}{sub -18} eV (FWHM = 4200{sup +1800}{sub -2000} km s{sup -1}) which corresponds to a radius of 20{sup +50}{sub -10} light days, for the virial production of 1.220 x 10{sup 7} M{sub sun} in NGC 5548. To quantitatively investigate the origin of the narrow Fe line by the reverberation mapping method, we compare the observed light curves of Fe Kalpha line with the predicted ones, which are obtained by convolving the continuum light curve with the transfer functions in a thin shell and an inclined disk. The best-fit result is given by the disk case with i = 30 deg. which is better than a fit to a constant flux of the Fe K line at the 92.7% level (F-test). However, the results with other geometries are also acceptable (P>50%). We find that the emitting radius obtained from the light curve is 25-37 light days, which is consistent with the radius derived from the Fe K line width. Combining the results of the line width and variation, the most likely site for the origin of the narrow iron lines is 20-40 light days away from the central engine, though other possibilities are not completely ruled out. This radius is larger than the Hbeta emitting parts of the broad-line region at 6-10 light days (obtained by the simultaneous optical observation), and smaller than the inner radius of the hot dust in NGC 5548 (at about 50 light days).« less

Observations of H-beta and He II lambda 4686 lines in the spectra of flares of UV Cet-type stars

NASA Astrophysics Data System (ADS)

Chugainov, P. F.; Petrov, P. P.; Scherbakov, A. G.

The main results of 45.4 hours of continuous spectroscopic and photoelectric B-band observations of AD Leo, DT Virgo, and YZ CMi are discussed. In two AD Leo flares and two YZ CMi flares, an increase of the central intensity of H-beta was observed 10-20 min before the maximum B-band brightness. The spectra of one AD Leo flare and one YZ CMi flare definitely indicate the formation of broad wings of H-beta occurring mainly during flare maximum. These flares surpass the other four in total optical energy. The Stark effect seems to be the most appropriate explanation for the origin of the wings. The upper limit of the equivalent widths of the He II wavelength 4686 line was higher than that in the quiet state. The equivalent width values cannot be explained by the cascade recombination mechanism if the ratio of optical and X-ray luminosities is nearly the same for all flares of UV Cet-type stars.

Physically transient photonics: random versus distributed feedback lasing based on nanoimprinted DNA.

PubMed

Camposeo, Andrea; Del Carro, Pompilio; Persano, Luana; Cyprych, Konrad; Szukalski, Adam; Sznitko, Lech; Mysliwiec, Jaroslaw; Pisignano, Dario

2014-10-28

Room-temperature nanoimprinted, DNA-based distributed feedback (DFB) laser operation at 605 nm is reported. The laser is made of a pure DNA host matrix doped with gain dyes. At high excitation densities, the emission of the untextured dye-doped DNA films is characterized by a broad emission peak with an overall line width of 12 nm and superimposed narrow peaks, characteristic of random lasing. Moreover, direct patterning of the DNA films is demonstrated with a resolution down to 100 nm, enabling the realization of both surface-emitting and edge-emitting DFB lasers with a typical line width of <0.3 nm. The resulting emission is polarized, with a ratio between the TE- and TM-polarized intensities exceeding 30. In addition, the nanopatterned devices dissolve in water within less than 2 min. These results demonstrate the possibility of realizing various physically transient nanophotonics and laser architectures, including random lasing and nanoimprinted devices, based on natural biopolymers.

Computer enhancement of ESR spectra of magnetite nanoparticles

NASA Astrophysics Data System (ADS)

Dobosz, B.; Krzyminiewski, R.; Koralewski, M.; Hałupka-Bryl, M.

2016-06-01

We present ESR measurements of non-interacting magnetic nanoparticle systems. Temperature and orientational dependence of ESR spectra were measured for Fe3O4 nanoparticle coated by dextran or oleic acid, frozen in different magnetic field. Several parameters describing magnetic properties such as g-factor, line width, the anisotropy constant were calculated and discussed. The ESR spectra of investigated nanoparticles were also subjected to Computer Resolution Enhancement Method (CREM). This procedure allows to separate a narrow line on the background of the broad line, which presence in this type of materials was recognized in the recent literature and have been further discussed in the paper. CREM is a valuable tool for monitoring of changes on the surface of magnetic core of nanoparticles.

PECULIAR NEAR-NUCLEUS OUTGASSING OF COMET 17P/HOLMES DURING ITS 2007 OUTBURST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qi, Chunhua; Gurwell, Mark A.; Wilner, David J.

2015-01-20

We present high angular resolution Submillimeter Array observations of the outbursting Jupiter family comet 17P/Holmes on 2007 October 26-29, achieving a spatial resolution of 2.''5, or ∼3000 km at the comet distance. The observations resulted in detections of the rotational lines CO 3-2, HCN 4-3, H{sup 13}CN 4-3, CS 7-6, H{sub 2}CO 3{sub 1,} {sub 2}-2{sub 1,} {sub 1}, H{sub 2}S 2{sub 2,} {sub 0}-2{sub 1,} {sub 1}, and multiple CH{sub 3}OH lines, along with the associated dust continuum at 221 and 349 GHz. The continuum has a spectral index of 2.7 ± 0.3, slightly steeper than blackbody emission from large dust particles.more » From the imaging data, we identify two components in the molecular emission. One component is characterized by a relatively broad line width (∼1 km s{sup –1} FWHM) exhibiting a symmetric outgassing pattern with respect to the nucleus position. The second component has a narrower line width (<0.5 km s{sup –1} FWHM) with the line center redshifted by 0.1-0.2 km s{sup –1} (cometocentric frame), and shows a velocity shift across the nucleus position with the position angle gradually changing from 66° to 30° within the four days of observations. We determine distinctly different CO/HCN ratios for each of the components. For the broad-line component we find CO/HCN < 7, while in the narrow-line component, CO/HCN = 40 ± 5. We hypothesize that the narrow-line component originates from the ice grain halo found in near-nucleus photometry, believed to be created by sublimating recently released ice grains around the nucleus during the outburst. In this interpretation, the high CO/HCN ratio of this component reflects the more pristine volatile composition of nucleus material released in the outburst.« less

Insights into quasar UV spectra using unsupervised clustering analysis

NASA Astrophysics Data System (ADS)

Tammour, A.; Gallagher, S. C.; Daley, M.; Richards, G. T.

2016-06-01

Machine learning techniques can provide powerful tools to detect patterns in multidimensional parameter space. We use K-means - a simple yet powerful unsupervised clustering algorithm which picks out structure in unlabelled data - to study a sample of quasar UV spectra from the Quasar Catalog of the 10th Data Release of the Sloan Digital Sky Survey (SDSS-DR10) of Paris et al. Detecting patterns in large data sets helps us gain insights into the physical conditions and processes giving rise to the observed properties of quasars. We use K-means to find clusters in the parameter space of the equivalent width (EW), the blue- and red-half-width at half-maximum (HWHM) of the Mg II 2800 Å line, the C IV 1549 Å line, and the C III] 1908 Å blend in samples of broad absorption line (BAL) and non-BAL quasars at redshift 1.6-2.1. Using this method, we successfully recover correlations well-known in the UV regime such as the anti-correlation between the EW and blueshift of the C IV emission line and the shape of the ionizing spectra energy distribution (SED) probed by the strength of He II and the Si III]/C III] ratio. We find this to be particularly evident when the properties of C III] are used to find the clusters, while those of Mg II proved to be less strongly correlated with the properties of the other lines in the spectra such as the width of C IV or the Si III]/C III] ratio. We conclude that unsupervised clustering methods (such as K-means) are powerful methods for finding `natural' binning boundaries in multidimensional data sets and discuss caveats and future work.

The physical relation between disc and coronal emission in quasars

NASA Astrophysics Data System (ADS)

Lusso, Elisabeta; Risaliti, Guido

2017-12-01

We propose a modified version of the observed non-linear relation between the X-ray (2 keV) and the ultraviolet (2500 Å) emission in quasars (i.e. LX ∝ LUV^γ ) which involves the full width at half-maximum, FWHM, of the broad emission line, i.e. LX ∝ L_UV^γ FWHM^β. By analysing a sample of 550 optically selected non-jetted quasars in the redshift range of 0.36–2.23 from the Sloan Digital Sky Survey cross matched with the XMM-Newton catalogue 3XMM-DR6, we found that the additional dependence of the observed LX ‑ LUV correlation on the FWHM of the MgII broad emission line is statistically significant. Our statistical analysis leads to a much tighter relation with respect to the one neglecting FWHM, and it does not evolve with redshift. We interpret this new relation within an accretion disc corona scenario where reconnection and magnetic loops above the accretion disc can account for the production of the primary X-ray radiation. For a broad line region size depending on the disc luminosity as R_blr ∝ L^0.5 , we find that L_X ∝ L_UV^4/7 FWHM^4/7, which is in very good agreement with the observed correlation.

A VLT VIMOS study of the anomalous BCD Mrk996: mapping the ionized gas kinematics and abundances

NASA Astrophysics Data System (ADS)

James, B. L.; Tsamis, Y. G.; Barlow, M. J.; Westmoquette, M. S.; Walsh, J. R.; Cuisinier, F.; Exter, K. M.

2009-09-01

A study of the blue compact dwarf (BCD) galaxy Mrk996 based on high-resolution optical Very Large Telescope Visible Multi-Object Spectrograph integral field unit spectroscopy is presented. Mrk996 displays multicomponent line emission, with most line profiles consisting of a narrow, central Gaussian [full width at half-maximum (FWHM) ~ 110kms-1] with an underlying broad component (FWHM ~ 400kms-1). The broad HI Balmer component splits into two separate broad components inside a 1.5-arcsec radius from the nucleus; these are attributed to a two-armed minispiral. This spiral-like nucleus rotates in the same sense as the extended narrow line ionized gas but is offset by ~50kms-1 from the systemic velocity of the galaxy. The rotation curve of Mrk996 derived from the Hα narrow component yields a total mass of 5 × 108Msolar within a radius of 3kpc. From the Hα luminosity we infer a global star formation rate of ~2Msolaryr-1. The high excitation energy, high critical density [OIII] λ4363 and [NII] λ5755 lines are only detected from the inner region and exist purely in broad component form, implying unusual excitation conditions. Surface brightness, radial velocity and FWHM maps for several emission components are presented. A separate physical analysis of the broad and narrow emission line regions is undertaken. We derive an upper limit of 10000K for the electron temperature of the narrow line gas, together with an electron density of 170cm-3, typical of normal HII regions. For the broad line component, measured [OIII] and [FeIII] diagnostic line ratios are consistent with a temperature of 11000K and an electron density of 107cm-3. The broad line emission regions show N/H and N/O enrichment factors of ~20 relative to the narrow line regions, but no He/H, O/H, S/H or Ar/H enrichment is inferred. Previous studies indicated that Mrk996 showed anomalously high N/O ratios compared with BCDs of a similar metallicity. Our multicomponent analysis yields a revised metallicity of >=0.5Zsolar (12 + logO/H = 8.37) for both the narrow and broad gas components, significantly higher than previous studies. As a result the narrow line region's N/O ratio is now typical for the galaxy's metallicity. The narrow line component's N/O ratio peaks outside the core region, spatially correlating with ~3-Myr-old stellar populations. The dominant line excitation mechanism is photoionization by the ~3000 Wolf-Rayet stars and ~150000 O-type stars estimated to be present in the core. This is indeed a peculiar BCD, with extremely dense zones of gas in the core, through which stellar outflows and possible shock fronts permeate contributing to the excitation of the broad line emission. Based on observations made with ESO telescopes at the Paranal Observatory under programme ID 078.B-0353(A). E-mail: bj@star.ucl.ac.uk (BLJ); tsamis@iaa.es (YGT)

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Filiz Ak, N.; Brandt, W. N.; Schneider, D. P.

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 Cmore » 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.« less

The Mysterious 6565 Å Absorption Feature of the Galactic Halo

NASA Astrophysics Data System (ADS)

Sethi, Shiv K.; Shchekinov, Yuri; Nath, Biman B.

2017-12-01

We consider various possible scenarios to explain the recent observation of what has been called a broad Hα absorption in our Galactic halo, with peak optical depth τ ≃ 0.01 and equivalent width W≃ 0.17 \\mathringA . We show that the absorbed feature cannot arise from the circumgalactic and ISM Hα absorption. As the observed absorption feature is quite broad ({{Δ }}λ ≃ 30 \\mathringA ), we also consider CNO lines that lie close to Hα as possible alternatives to explain the feature. We show that such lines could also not account for the observed feature. Instead, we suggest that it could arise from diffuse interstellar bands (DIBs) carriers or polyaromatic hydrocarbons (PAHs) absorption. While we identify several such lines close to the Hα transition, we are unable to determine the molecule responsible for the observed feature, partly because of selection effects that prevent us from identifying DIBs/PAHs features close to Hα using local observations. Deep integration of a few extragalactic sources with high spectral resolution might allow us to distinguish between different possible explanations.

CHEMICAL EVOLUTION OF THE UNIVERSE AT 0.7 < z < 1.6 DERIVED FROM ABUNDANCE DIAGNOSTICS OF THE BROAD-LINE REGION OF QUASARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sameshima, H.; Yoshii, Y.; Kawara, K., E-mail: sameshima@cc.kyoto-su.ac.jp

2017-01-10

We present an analysis of Mg ii λ 2798 and Fe ii UV emission lines for archival Sloan Digital Sky Survey (SDSS) quasars to explore the diagnostics of the magnesium-to-iron abundance ratio in a broad-line region cloud. Our sample consists of 17,432 quasars selected from the SDSS Data Release 7 with a redshift range of 0.72 <  z  < 1.63. A strong anticorrelation between the Mg ii equivalent width (EW) and the Eddington ratio is found, while only a weak positive correlation is found between the Fe ii EW and the Eddington ratio. To investigate the origin of these differing behaviors ofmore » Mg ii and Fe ii emission lines, we perform photoionization calculations using the Cloudy code, where constraints from recent reverberation mapping studies are considered. We find from calculations that (1) Mg ii and Fe ii emission lines are created at different regions in a photoionized cloud, and (2) their EW correlations with the Eddington ratio can be explained by just changing the cloud gas density. These results indicate that the Mg ii/Fe ii flux ratio, which has been used as a first-order proxy for the Mg/Fe abundance ratio in chemical evolution studies with quasar emission lines, depends largely on the cloud gas density. By correcting this density dependence, we propose new diagnostics of the Mg/Fe abundance ratio for a broad-line region cloud. In comparing the derived Mg/Fe abundance ratios with chemical evolution models, we suggest that α -enrichment by mass loss from metal-poor intermediate-mass stars occurred at z  ∼ 2 or earlier.« less

THE CONNECTIONS BETWEEN THE UV AND OPTICAL Fe ii EMISSION LINES IN TYPE 1 AGNs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kovacević-Dojcinović, Jelena; Popović, Luka Č., E-mail: jkovacevic@aob.bg.ac.rs, E-mail: lpopovic@aob.bg.ac.rs

We investigate the spectral properties of the UV (λλ2650–3050 Å) and optical (λλ4000–5500 Å) Fe ii emission features in a sample of 293 Type 1 active galactic nuclei (AGNs) from the Sloan Digital Sky Survey database. We explore different correlations between their emission line properties, as well as the correlations with other emission lines from the spectral range. We find several interesting correlations and outline the most interesting results as follows. (i) There is a kinematical connection between the UV and optical Fe ii lines, indicating that the UV and optical Fe ii lines originate from the outer part ofmore » the broad line region, the so-called intermediate line region. (ii) The unexplained anticorrelations of the optical Fe ii equivalent width (EW Fe ii{sub opt}) versus EW [O iii] 5007 Å and EW Fe ii{sub opt} versus FWHM Hβ have not been detected for the UV Fe ii lines. (iii) The significant averaged redshift in the UV Fe ii lines, which is not present in optical Fe ii, indicates an inflow in the UV Fe ii emitting clouds, and probably their asymmetric distribution. (iv) Also, we confirm the anticorrelation between the intensity ratio of the optical and UV Fe ii lines and the FWHM of Hβ, and we find the anticorrelations of this ratio with the widths of Mg ii 2800 Å, optical Fe ii, and UV Fe ii. This indicates a very important role for the column density and microturbulence in the emitting gas. We discuss the starburst activity in high-density regions of young AGNs as a possible explanation of the detected optical Fe ii correlations and intensity line ratios of the UV and optical Fe ii lines.« less

Extremely long nonradiative relaxation of photoexcited graphane is greatly accelerated by oxidation: time-domain ab initio study.

PubMed

Nelson, Tammie R; Prezhdo, Oleg V

2013-03-06

Graphane and its derivatives are stable and extremely thin, wide band gap semiconductors that promise to replace conventional semiconductors in electronics, catalysis, and energy applications, greatly reducing device size and power consumption. In order to be useful, band-gap excitations in these materials should be long lived and nonradiative energy losses to heat should be slow. We use state-of-the-art nonadiabatic molecular dynamics combined with time-dependent density functional theory in order to determine the nonradiative lifetime and radiative line width of the lowest energy singlet excitations in pure and oxidized graphanes. We predict that pure graphane has a very long nonradiative decay time, on the order of 100 ns, while epoxy- and hydroxy-graphanes lose electronic excitation energy to heat 10-20 times faster. The luminescence line width is 1.5 times larger in pristine graphane compared to its oxidized forms, and at room temperature, it is on the order of 50 meV. Hydroxylation lowers graphane's band gap, while epoxidation increases the gap. The nonradiative decay and luminescence line width of pure graphane are governed by electron coupling to the 1200 cm(-1) vibrational mode. In the oxidized forms of graphane, the electronic excitations couple to a broad range of vibrational modes, rationalizing the more rapid nonradiative decay in these systems. The slow electron-phonon energy losses in graphane compared to other graphene derivatives, such as carbon nanotubes and nanoribbons, indicate that graphanes are excellent candidates for semiconductor applications.

Broad-band frequency references in the near-infrared: Accurate dual comb spectroscopy of methane and acetylene

NASA Astrophysics Data System (ADS)

Zolot, A. M.; Giorgetta, F. R.; Baumann, E.; Swann, W. C.; Coddington, I.; Newbury, N. R.

2013-03-01

The Doppler-limited spectra of methane between 176 THz and 184 THz (5870-6130 cm-1) and acetylene between 193 THz and 199 THz (6430-6630 cm-1) are acquired via comb-tooth resolved dual comb spectroscopy with frequency accuracy traceable to atomic standards. A least squares analysis of the measured absorbance and phase line shapes provides line center frequencies with absolute accuracy of 0.2 MHz, or less than one thousandth of the room temperature Doppler width. This accuracy is verified through comparison with previous saturated absorption spectroscopy of 37 strong isolated lines of acetylene. For the methane spectrum, the center frequencies of 46 well-isolated strong lines are determined with similar high accuracy, along with the center frequencies for 1107 non-isolated lines at lower accuracy. The measured methane line-center frequencies have an uncertainty comparable to the few available laser heterodyne measurements in this region but span a much larger optical bandwidth, marking the first broad-band measurements of the methane 2ν3 region directly referenced to atomic frequency standards. This study demonstrates the promise of dual comb spectroscopy to obtain high resolution broadband spectra that are comparable to state-of-the-art Fourier-transform spectrometer measurements but with much improved frequency accuracy.Work of the US government, not subject to US copyright.

The hot DOA1 degenerate HZ 21 - A search for circumstellar/photospheric metals and peculiar absorption at He II

NASA Technical Reports Server (NTRS)

Fritz, M. L.; Leckenby, H.; Sion, E. M.; Vauclair, G.; Liebert, J.

1990-01-01

A high-resolution IUE spectrum of the hot DO1 degenerate HZ 21 was obtained by combining US1 + European 2 low-background observing shifts. The SWP image reveals a rich spectrum of interstellar absorption lines with an average velocity in the line of sight to HZ 21 of -30 km/s. However, there is no clear evidence of any highly or lowly ionized metal features which could be attributed to circumstellar, wind, or photospheric absorption. There is, however, a broad absorption trough at He II (1640) which was not unexpected, given the clear presence of He II (4686) absorption in this star's optical spectrum. The velocity width of He II (1640) appears consistent with photospheric absorption wings which appear to flank the geocoronal Ly-alpha emission feature. The He II (1640) feature reveals what appears to be a broad (310 km/s) emission reversal. Evidence is provided that the emission reversal is probably real.

EVIDENCE FOR PHOTOIONIZATION-DRIVEN BROAD ABSORPTION LINE VARIABILITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Tinggui; Yang, Chenwei; Wang, Huiyuan

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 intrinsicmore » 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.« less

THE CORES OF THE Fe K{alpha} LINES IN ACTIVE GALACTIC NUCLEI: AN EXTENDED CHANDRA HIGH ENERGY GRATING SAMPLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shu, X. W.; Wang, J. X.; Yaqoob, T.

We extend the study of the core of the Fe K{alpha} emission line at {approx}6.4 keV in Seyfert galaxies reported by Yaqoob and Padmanabhan using a larger sample observed by the Chandra high-energy grating (HEG). The sample consists of 82 observations of 36 unique sources with z < 0.3. Whilst heavily obscured active galactic nuclei are excluded from the sample, these data offer some of the highest precision measurements of the peak energy of the Fe K{alpha} line, and the highest spectral resolution measurements of the width of the core of the line in unobscured and moderately obscured (N {submore » H} < 10{sup 23} cm{sup -2}) Seyfert galaxies to date. From an empirical and uniform analysis, we present measurements of the Fe K{alpha} line centroid energy, flux, equivalent width (EW), and intrinsic width (FWHM). The Fe K{alpha} line is detected in 33 sources, and its centroid energy is constrained in 32 sources. In 27 sources, the statistical quality of the data is good enough to yield measurements of the FWHM. We find that the distribution in the line centroid energy is strongly peaked around the value for neutral Fe, with over 80% of the observations giving values in the range 6.38-6.43 keV. Including statistical errors, 30 out of 32 sources ({approx}94%) have a line centroid energy in the range 6.35-6.47 keV. The mean EW, among the observations in which a non-zero lower limit could be measured, was 53 {+-} 3 eV. The mean FWHM from the subsample of 27 sources was 2060 {+-} 230 km s{sup -1}. The mean EW and FWHM are somewhat higher when multiple observations for a given source are averaged. From a comparison with the H{beta} optical emission-line widths (or, for one source, Br{alpha}), we find that there is no universal location of the Fe K{alpha} line-emitting region relative to the optical broad-line region (BLR). In general, a given source may have contributions to the Fe K{alpha} line flux from parsec-scale distances from the putative black hole, down to matter a factor {approx}2 closer to the black hole than the BLR. We confirm the presence of the X-ray Baldwin effect, an anti-correlation between the Fe K{alpha} line EW and X-ray continuum luminosity. The HEG data have enabled isolation of this effect to the narrow core of the Fe K{alpha} line.« less

Line width resonance of the longitudinal optical phonon in GaAs:N

NASA Astrophysics Data System (ADS)

Mialitsin, Aleksej; Mascarenhas, Angelo

2013-03-01

We extend resonant Raman scattering studies of Mascarenhas et al. [PRB68, 233201 (2003)] of GaAs1-xNx to the ultra-dilute nitrogen doping concentrations, whereby we unambiguously resolve the line width resonances of the LO phonon. A discontinuity is observed in the LO phonon line width resonance energy as a function of concentration. With decreasing nitrogen concentration the EW line width resonance energy reduces by ca. 40 meV at x = 0 . 4 % . This value corresponds to the concentration, at which the localized to delocalized transition manifests itself in the electro-reflectance signature line widths.

Observation of magnetic anomalies in one-step solvothermally synthesized nickel-cobalt ferrite nanoparticles.

PubMed

Datt, Gopal; Sen Bishwas, Mousumi; Manivel Raja, M; Abhyankar, A C

2016-03-07

Magnetic anomalies corresponding to the Verwey transition and reorientation of anisotropic vacancies are observed at 151 K and 306 K, respectively, in NiCoFe2O4 nanoparticles (NPs) synthesized by a modified-solvothermal method followed by annealing. Cationic disorder and spherical shape induced non-stoichiometry suppress the Verwey transition in the as-synthesized NPs. On the other hand, reorientation of anisotropic vacancies is quite robust. XRD and electron microscopy investigations confirm a single phase spinel structure and the surface morphology of the as-synthesized NPs changes from spherical to octahedral upon annealing. Rietveld analysis reveals that the Ni(2+) ions migrate from tetrahedral (A) to octahedral (B) sites upon annealing. The Mössbauer results show canted spins in both the NPs and the strength of superexchange is stronger in Co-O-Fe than Ni-O-Fe. Magnetic force images show that the as-synthesised NPs are single-domain whereas the annealed NPs are multi-domain octahedral particles. The FMR study reveals that both the NPs have a broad FMR line-width; and resonance properties are consistent with the random anisotropy model. The broad inhomogeneous FMR line-width, observation of the Verwey transition, tuning of the magnetic domain structure as well as the magnetic properties suggest that the NiCoFe2O4 ferrite NPs may be promising for future generation spintronics, magneto-electronics, and ultra-high-density recording media as well as for radar absorbing applications.

The quasar proximity effect in an equivalent-width-limited sample of the Lyman-alpha forest

NASA Technical Reports Server (NTRS)

Chernomordik, Viktor V.; Ozernoy, Leonid M.

1993-01-01

We have obtained a simple analytical approximation to the relationship between a rest-frame equivalent-width distribution for Ly-alpha forest absorption lines, N(W), and an H I column density distribution of the observed cloud number, N(N). Assuming a simple power-law form for N(N) proportional to N exp (1-beta), it is shown that beta = 1.4 turns out to agree fairly well with the observed form of N(W) in a broad range of column densities. We present a theoretical analysis of how the 'proximity effect' influences a W-limited sample of Ly-alpha forest lines. It is shown that this influence is considerably smaller than has been found before for a N-limited sample, for which an approximate value of beta was assumed rather than derived as has been done, for a W-limited sample, in the present paper. As a result, available observational data appear to be still consistent with the conjecture that the observed population of QSOs is the major source of the UV background at redshifts z about 2-4.

A new X-ray spectral observation of NGC 1068

NASA Technical Reports Server (NTRS)

Marshall, F. E.; Netzer, H.; Arnaud, K. A.; Boldt, E. A.; Holt, S. S.; Jahoda, K. M.; Kelley, R.; Mushotzky, R. F.; Petre, R.; Serlemitsos, P. J.

1993-01-01

A new X-ray observation of NGC 1068, in which improved spectral resolution (R is approximately equal to 40) and broad energy range provide important new constraints on models for this galaxy, is reported. The observed X-ray continuum of NGC 1068 from 0.3 to 10 keV is well fitted as the sum of two power-law spectra with no evidence for absorption intrinsic to the source. Strong Fe K emission lines with a total equivalent width of 2700 eV were detected due to iron less ionized than Fe XX and to iron more ionized than Fe XXIII. No evidence was seen for lines due to the recombination of highly ionized oxygen with an upper limit for the O Ly-alpha emission line of 40 eV. The discovery of multiple Fe K and Fe L emission lines indicates a broad range of ionization states for this gas. The X-ray emission from the two components is modeled for various geometries using a photoionization code that calculates the temperature and ionization state of the gas. Typical model parameters are a total Compton depth of a few percent, an inner boundary of the hot component of about 1 pc, and an inner boundary of the warm component of about 20 pc.

Evaluation of width and width uniformity of near-field electrospinning printed micro and sub-micrometer lines based on optical image processing

NASA Astrophysics Data System (ADS)

Zhao, Libo; Xia, Yong; Hebibul, Rahman; Wang, Jiuhong; Zhou, Xiangyang; Hu, Yingjie; Li, Zhikang; Luo, Guoxi; Zhao, Yulong; Jiang, Zhuangde

2018-03-01

This paper presents an experimental study using image processing to investigate width and width uniformity of sub-micrometer polyethylene oxide (PEO) lines fabricated by near-filed electrospinning (NFES) technique. An adaptive thresholding method was developed to determine the optimal gray values to accurately extract profiles of printed lines from original optical images. And it was proved with good feasibility. The mechanism of the proposed thresholding method was believed to take advantage of statistic property and get rid of halo induced errors. Triangular method and relative standard deviation (RSD) were introduced to calculate line width and width uniformity, respectively. Based on these image processing methods, the effects of process parameters including substrate speed (v), applied voltage (U), nozzle-to-collector distance (H), and syringe pump flow rate (Q) on width and width uniformity of printed lines were discussed. The research results are helpful to promote the NFES technique for fabricating high resolution micro and sub-micro lines and also helpful to optical image processing at sub-micro level.

NGC 5506 unmasked as a Narrow Line Seyfert 1:. A direct view of the broad line region using near-IR spectroscopy

NASA Astrophysics Data System (ADS)

Nagar, N. M.; Oliva, E.; Marconi, A.; Maiolino, R.

2002-08-01

This letter presents incontrovertible evidence that NGC 5506 is a Narrow Line Seyfert 1 (NLSy1). Our new 0.9-1.4 mu m spectrum of its nucleus clearly shows the permitted O I lambda 1.1287 mu m line (with full width at half maximum <2000 km s-1) and the ``1 micron Fe II lines''. These lines can only originate in the optically-thick broad line region (BLR) and, among Seyfert nuclei the latter series of lines are seen only in NLSy1s. The obscuration to the BLR, derived from a rough estimate of the O I lambda 1.1287 mu m/O I lambda 8446 ratio and from the reddening of the near-IR Paschen lines, is AV > 5. Together, these results make NGC 5506 the first identified case of an optically-obscured NLSy1. This new classification helps explain its radio to X-ray properties, which until now were considered highly anomalous. However, interesting new concerns are raised: e.g., NGC 5506 is unusual in hosting both a ``type 1'' AGN and a nuclear water vapor megamaser. As the brightest known NLSy1, NGC 5506 is highly suitable for study at wavebands less affected by obscuration. Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Centro Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias.

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

NASA Astrophysics Data System (ADS)

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

2006-11-01

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

A new method to measure the virial factors in the reverberation mapping of active galactic nuclei

NASA Astrophysics Data System (ADS)

Liu, H. T.; Feng, H. C.; Bai, J. M.

2017-04-01

Based on the gravitational red shift, which is a prediction of Einstein's general relativity theory, of broad optical emission lines in active galactic nuclei (AGNs), a new method is proposed to estimate the virial factors f in measuring black hole masses MRM by the reverberation mapping of AGNs. The factors f can be measured based on two physical quantities, I.e. the gravitational red shifts zg and the full widths at half maxima vFWHM of broad lines. In the past, it has been difficult to determine the factors f for individual AGNs. We apply this new method to several reverberation-mapped type 1 Seyfert galaxies. There is a correlation between f and the radius of the broad-line region (BLR) rBLR, f=5.4 r_{BLR}^{0.3}, for the gravitationally red-shifted broad lines He II, He I, Hβ and Hα in the narrow-line type 1 Seyfert galaxy (NLS1) Mrk 110. This correlation results from the influence of the radiation pressure of the accretion disc on the BLR clouds. This influence seems to be more important than usually thought so in AGNs. Mrk 110 has f ≈ 8-16, distinctly larger than the mean ≈ 1 usually used to estimate MRM for vFWHM. NGC 4593 and NLS1 Mrk 486 have f ≈ 3 and f ≈ 9, respectively. Higher f values of several tens are derived for three other NLS1s. There is a correlation between f and accretion rate dot{M}_{f=1}, f=6.8dot{M}^{0.4}_{f=1} for five objects, where dot{M}_{f=1}=dot{M}_{bullet }/L_{Edd}c^{-2} as f = 1 is assumed when estimating MRM used in the Eddington luminosity LEdd, dot{M}_{bullet } is the mass accretion rate, and c is the speed of light. These larger f values will produce higher MRM values and lower Eddington ratios.

Investigations of a New Eclipsing Cataclysmic Variable HBHA 4705-03

NASA Astrophysics Data System (ADS)

Yakin, D. G.; Suleimanov, V. F.; Shimansky, V. V.; Vlasyuk, V. V.; Spiridonova, O. I.

2013-01-01

Results of photometric and spectroscopic investigations of the recently discovered eclipsing cataclysmic variable star HBHA 4705-03 are presented. The emission spectra of the system show broad hydrogen and helium emission lines. The bright spots with an approximately zero velocity components are found in the Doppler maps for the hydrogen and ionized helium lines. The disc structure is more prominent in the maps for the neutral helium lines. The masses of the components (MWD = 0.54 ± 0.10M⊙ and MRD = 0.45 ± 0.05 M⊙), and the orbit inclination (i = 71.°8 ± 0.°7) were estimated using the radial velocity light curve and the eclipse width. The modeling of the light curve allows us to evaluate the bright spot parameters and the mass accretion rate (M ≍ 2 ·1017 g s-1).

Simulating the evolution of optically dark HI clouds in the Virgo cluster : will no-one rid me of this turbulent sphere ?

NASA Astrophysics Data System (ADS)

Taylor, R.; Wünsch, R.; Palouš, J.

2018-05-01

Most detected neutral atomic hydrogen (HI) at low redshift is associated with optically bright galaxies. However, a handful of HI clouds are known which appear to be optically dark and have no nearby potential progenitor galaxies, making tidal debris an unlikely explanation. In particular, 6 clouds identified by the Arecibo Galaxy Environment Survey are interesting due to the combination of their small size, isolation, and especially their broad line widths atypical of other such clouds. A recent suggestion is that these clouds exist in pressure equilibrium with the intracluster medium, with the line width arising from turbulent internal motions. Here we explore that possibility by using the FLASH code to perform a series of 3D hydro simulations. Our clouds are modelled using spherical Gaussian density profiles, embedded in a hot, low-density gas representing the intracluster medium. The simulations account for heating and cooling of the gas, and we vary the structure and strength of their internal motions. We create synthetic HI spectra, and find that none of our simulations reproduce the observed cloud parameters for longer than ˜100 Myr : the clouds either collapse, disperse, or experience rapid heating which would cause ionisation and render them undetectable to HI surveys. While the turbulent motions required to explain the high line widths generate structures which appear to be inherently unstable, making this an unlikely explanation for the observed clouds, these simulations demonstrate the importance of including the intracluster medium in any model seeking to explain the existence of these objects.

Modeling the temporal and spatial variations of the vertical structure of Jupiter's atmosphere using observations of the 3-0 hydrogen quadrupole lines

NASA Technical Reports Server (NTRS)

Cunningham, C. C.; Hunten, D. M.; Tomasko, M. G.

1986-01-01

An observational program was established in 1983 to monitor the spatial and temporal variations in the Jovian atmosphere over short and long time scales. The program involves tracking several different longitudes as they rotate around the planet from one limb to another. This tracking experiment was done at many different wavelengths including the 3-0 S(1) and S(0) hydrogen quadrupole lines as well as several broad band methane absorptions. The June 1983 hydrogen quadrupole data was reduced and equivalent widths were measured for approximately 25 east-west positions across the planet at 7 different latitudes for both wavelengths. The data for the South Tropical Zone (20 deg. S) was modeled extensively and the effects of the various model parameters on the value of the calculated equivalent widths of both lines was measured as a longitude rotated from the east (or morning) limb to the west (or evening) limb. The value of the equivalent width is also quite sensitive to the height of the NH3 cloud top and to the value used for the single scattering albedo. A combination of these parameters changing on a diurnal time scale could also explain these observations. This gradual increase from one limb to the other appears in the data for both the North and South Equatorial Belts as well as the equatorial region and the North Tropical Zone. Models that used only normal hydrogen and models that used only equilibrium hydrogen were studied.

Characterizing Quasar Outflows I: Sample, Spectral Measurements

NASA Astrophysics Data System (ADS)

Ganguly, Rajib; Christenson, D. H.; Richmond, J. M.; Derseweh, J. A.; Robbins, J. M.; Townsend, S. L.; Stark, M. A.

2012-05-01

Galaxy evolution models have shown that quasars are a crucial ingredient in the evolution of massive galaxies. Outflows play a key role in the story of quasars and their host galaxies, by helping regulate the accretion process, the star-formation rate and mass of the host galaxy (i.e., feedback). The prescription for modeling outflows as a contributor to feedback requires knowledge of the outflow velocity, geometry, and column density. In particular, we need to understand how these depend on physical parameters and how much is determined stochastically (and with what distribution). For this purpose, we are examining a sample of 11000 z=1.7-2.0 quasars from the Sloan Digital Sky Survey. This redshift range permits the following from the SDSS spectra: (1) separation of objects that do and do not exhibit outflows; (2) classification/measurement of outflow properties (ionization, velocity, velocity width); and (3) measurements of UV emission line and continuum parameters. In this poster, we subjectively divide these quasars into four categories: broad absorption-line quasars (2700 objects), associated absorption-line quasars (1700 objects), reddened quasars (160 objects), and unabsorbed/unreddened quasars (6300 objects). We present measurements of the absorption (velocities, velocity widths, equivalent widths), composite spectral profiles of outflows as a function of velocity, as well as measurements of the continuum and CIV, MgII, and FeII emission-line properties. In accompanying posters, we add photometry from the rest-frame X-ray (ROSAT and Chandra), EUV (GALEX), optical (2MASS), and infrared (WISE) bands to complete the SED. The continuum and emission-line measurements from the SDSS spectra and accompanying photometry provides estimates on the black hole masses, bolometric luminsosities, and SED. We consider empirically how these affect the outflow properties. This material is based upon work supported by the National Aeronautics and Space Administration under Grant No. 09-ADP09-0016 issued through the Astrophysics Data Analysis Program.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plotkin, Richard M.; Gallo, Elena; Shemmer, Ohad

Over the past 15 yr, examples of exotic radio-quiet quasars with intrinsically weak or absent broad emission line regions (BELRs) have emerged from large-scale spectroscopic sky surveys. Here, we present spectroscopy of seven such weak emission line quasars (WLQs) at moderate redshifts (z = 1.4–1.7) using the X-shooter spectrograph, which provides simultaneous optical and near-infrared spectroscopy covering the rest-frame ultraviolet (UV) through optical. These new observations effectively double the number of WLQs with spectroscopy in the optical rest-frame, and they allow us to compare the strengths of (weak) high-ionization emission lines (e.g., C iv) to low-ionization lines (e.g., Mg ii,more » Hβ, Hα) in individual objects. We detect broad Hβ and Hα emission in all objects, and these lines are generally toward the weaker end of the distribution expected for typical quasars (e.g., Hβ has rest-frame equivalent widths ranging from 15–40 Å). However, these low-ionization lines are not exceptionally weak, as is the case for high-ionization lines in WLQs. The X-shooter spectra also display relatively strong optical Fe ii emission, Hβ FWHM ≲ 4000 km s{sup −1}, and significant C iv blueshifts (≈1000–5500 km s{sup −1}) relative to the systemic redshift; two spectra also show elevated UV Fe ii emission, and an outflowing component to their (weak) Mg ii emission lines. These properties suggest that WLQs are exotic versions of “wind-dominated” quasars. Their BELRs either have unusual high-ionization components, or their BELRs are in an atypical photoionization state because of an unusually soft continuum.« less

Narrow-band generation in random distributed feedback fiber laser.

PubMed

Sugavanam, Srikanth; Tarasov, Nikita; Shu, Xuewen; Churkin, Dmitry V

2013-07-15

Narrow-band emission of spectral width down to ~0.05 nm line-width is achieved in the random distributed feedback fiber laser employing narrow-band fiber Bragg grating or fiber Fabry-Perot interferometer filters. The observed line-width is ~10 times less than line-width of other demonstrated up to date random distributed feedback fiber lasers. The random DFB laser with Fabry-Perot interferometer filter provides simultaneously multi-wavelength and narrow-band (within each line) generation with possibility of further wavelength tuning.

Visible and Near-Infrared Spectroscopy of Seyfert 1 and Narrow-Line Seyfert 1 Galaxies

NASA Astrophysics Data System (ADS)

Rodríguez-Ardila, Alberto; Pastoriza, Miriani G.; Donzelli, Carlos J.

2000-01-01

This paper studies the continuum and emission-line properties of a sample composed of 16 normal Seyfert 1 and seven narrow-line Seyfert 1 (NLS1) galaxies using optical and near-IR CCD spectroscopy. The continuum emission of the galaxies can be described in terms of a combination of stellar population, a nonstellar continuum of power-law form, and Fe II emission. A significative difference in the optical spectral index between NLS1's and normal Seyfert 1's is observed; the latter is steeper. Most NLS1's show Fe II/Hβ ratios larger than those observed in the other Seyfert 1's. In the IRAS band, both groups of galaxies have very similar properties. We have searched for the presence of optically thin gas in the broad-line region (BLR) of the galaxies by comparing the broad O I λ8446 and Hα emission-line profiles. Our analysis show that in the NLS1's, both profiles are similar in shape and width. This result contradicts the hypothesis of thin gas emission in the high-velocity part of the BLR to explain the ``narrowness'' of broad optical permitted lines in these objects. Evidence of narrow O I λ8446 emission is found in six galaxies of our sample, implying that this line is not restricted to a pure BLR phenomenon. In the narrow-line region, we find similar luminosities in the permitted and high-ionization lines of NLS1's and normal Seyfert 1's. However, low-ionization lines such as [O I] λ6300, [O II] λ3727, and [S II] λλ6717, 6731 are intrinsically less luminous in NLS1's. Physical properties derived from density- and temperature-sensitive line ratios suggest that the [O II] and [S II] emitting zones are overlapping in normal Seyfert 1's and separated in NLS1's. Based on observations made at CASLEO. Complejo Astronómico El Leoncito (CASLEO) is operated under agreement between the Consejo Nacional de Investigaciones Científicas y técnicas de la República Argentina and the National Universities of La Plata, Córdoba and San Juán.

Uncertainties Associated with Theoretically Calculated N2-Broadened Half-Widths of H2O Lines

NASA Technical Reports Server (NTRS)

Ma, Q.; Tipping, R. H.; Gamache, R. R.

2010-01-01

With different choices of the cut-offs used in theoretical calculations, we have carried out extensive numerical calculations of the N2-broadend Lorentzian half-widths of the H2O lines using the modified Robert-Bonamy formalism. Based on these results, we are able to thoroughly check for convergence. We find that, with the low-order cut-offs commonly used in the literature, one is able to obtain converged values only for lines with large half-widths. Conversely, for lines with small half-widths, much higher cut-offs are necessary to guarantee convergence. We also analyse the uncertainties associated with calculated half-widths, and these are correlated as above. In general, the smaller the half-widths, the poorer the convergence and the larger the uncertainty associated with them. For convenience, one can divide all H2O lines into three categories, large, intermediate, and small, according to their half-width values. One can use this division to judge whether the calculated half-widths are converged or not, based on the cut-offs used, and also to estimate how large their uncertainties are. We conclude that with the current Robert- Bonamy formalism, for lines in category lone can achieve the accuracy requirement set by HITRAN, whereas for lines in category 3, it 'is impossible to meet this goal.

Combined Ultraviolet and Optical Spectra of 48 Low-Redshift QSOs and the Relation of the Continuum and Emission-Line Properties

NASA Astrophysics Data System (ADS)

Corbin, Michael R.; Boroson, Todd A.

1996-11-01

We present combined ultraviolet and optical spectra of 48 QSOs and Seyfert 1 galaxies in the redshift range 0.034-0.774. The UV spectra were obtained non-simultaneously with the optical and are derived from archival Hubble Space Telescope (HST) Faint Object Spectrograph and International Ultraviolet Explorer (IUE) observations. The sample consists of 22 radio- quiet objects, 12 flat radio spectrum radio-loud objects, and 14 steep radio spectrum objects, and it covers approximately 2.5 decades in ultraviolet continuum luminosity. The sample objects are among the most luminous known in this redshift range and include 3C 273 and Fairall 9, as well as many objects discovered in the Bright Quasar Survey. We measure and compare an array of emission-line and continuum parameters, including 2 keV X-ray luminosities derived from the Einstein database. We examine individual correlations and also apply a principal components analysis (PCA) in an effort to determine the underlying sources of variance among these observables. Our main results are as follows. 1. The C IV λ1549 profile asymmetry is correlated with the UV continuum luminosity measured at the position of that line, such that increasing continuum luminosity produces increasing redward asymmetry. This is the same correlation found between Hβ asymmetry and 2 keV luminosity in a larger sample of objects and appears to be followed by both radio-loud and radio-quiet sources. The C IV profile asymmetry is also correlated with the FWZI of the Lyα profile, with more redward asymmetric profiles associated with wider profile bases. The PCA reveals that the correlated increase in luminosity, C IV redward asymmetry, and profile base width accounts for over half the statistical variance in the sample. 2. There is a statistically significant difference between the FWZI distributions of the Lyα and Hβ lines, such that the former is wider on average by ~10^4^ km s^-1^. The FWHM values of the broad Hβ line are weakly correlated with those of C IV λ1549 and Lyα, and in contrast to the FWZI values the Hβ profiles are wider. Measures of the asymmetry of the Hβ and C IV profiles also show a weak correlation. The wavelength centroids at 3/4 maximum of the Lyα and C IV lines also show average blueshifts ~50-200 km s^-1^ from [O III] λ5007, versus an average redshift of 75 km s^-1^ for broad Hβ. 3. There is no clear evidence of narrow components to the stronger UV lines, even among objects in which the optical narrow lines including [O III] λλ4959, 5007 are unusually strong. We measure the average fractional contributions of such components to the Lyα and C III] λ1909 lines to be ~4%-5%, consistent with the findings from smaller samples. However, a sizable fraction (50%) of radio-loud objects display a narrow component of He II λ1640, the same as in the QSO population at intermediate redshifts, and such a component is likely to contribute to the other UV lines. We interpret the first result as the effect of a black hole mass/luminosity relation in which the profile widths and redward asymmetries are produced respectively by the virialized motions and gravitational redshift associated with 10^9^-10^10^ M_sun_ holes. This does not explain the cases of blueward profile asymmetries and blueshifted profile peaks, which require an effect acting oppositely to gravitational redshift. The peak redshift differences and relative weakness of the correlations between the UV profile widths and asymmetries and those of Hβ suggests a stratified ionization structure of the broad-line region (BLR), consistent with the variability studies of Seyfert 1 galaxies. Continuum variability and the dynamical evolution of the BLR gas may also influence these results. The difference between the Lyα and Hβ FWZI values provides additional evidence of an optically thin very broad line region (VBLR) lying interior to an intermediate line region (ILR) producing the profile cores. The smaller average FWHM values of the UV lines compared to Hβ indicate that they have a higher relative contribution of ILR emission, versus a more dominant VBLR component in the Balmer lines. The narrow He II λ1640 feature of radio-loud objects is likely associated with the inner regions of extended (100 kpc) ionized halos that are not present around radio-quiet objects, and which appear to be best explained as cooling flows around the QSO host galaxies.

Constraints on Cosmic-ray Acceleration Efficiency in Balmer Shocks of Two Young Type Ia Supernova Remnants in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Hovey, Luke; Hughes, John P.; McCully, Curtis; Pandya, Viraj; Eriksen, Kristoffer

2018-01-01

We present results from an optical study of two young Balmer-dominated remnants of SNIa in the Large Magellanic Cloud, 0509-67.5 and 0519-69.0, in an attempt to search for signatures of efficient cosmic-ray (CR) acceleration. We combine proper motion measurements from HST with corresponding optical spectroscopic measurements of the Hα line at multiple rim positions from VLT/FORS2 and SALT/RSS and compare our results to published Balmer shock models. Analysis of the optical spectra result in broad Hα widths in the range of 1800-4000 km s-1 for twelve separate Balmer-dominated filaments that show no evidence for forbidden line emission, the corresponding shock speeds from proper motion measurements span a range of 1600-8500 km s-1. Our measured values of shock speeds and broad Hα widths in 0509-67.5 and 0519-69.0 are fit well with a Balmer shock model that does not include effects of efficient CR acceleration. We determine an upper limit of 7%/Χ (95% confidence) on the CR acceleration efficiency for our ensemble of data points, where Χ is the ionization fraction of the pre-shock gas. The upper limits on the individual remnants are 6%/Χ (0509-67.5) and 11%/Χ (0519-69.0). These upper limits are below the integrated CR acceleration efficiency in the Tycho supernova remnant, where the shocks predominantly show little Hα emission, indicating that Balmer-dominated shocks are not efficient CR accelerators.

Highly ionized gas absorption in the disk and halo toward HD 167756 at 3.5 kilometers per second resolution

NASA Technical Reports Server (NTRS)

Savage, Blair D.; Sembach, Kenneth R.; Cardelli, Jason A.

1994-01-01

High-resolution spectra of interstellar Si IV, C IV, and N V absorption lines along the 4 kpc path to the inner Galaxy star HD 167756 at z = -0.85 kpc are presented. The spectra were obtained with the echelle mode of Goddard High Resolution Spectrograph (GHRS) aboard the Hubble Space Telescope (HST) and have signal-to-noise ratios ranging from 23 to 38. The high resolution of the measurements full width at half maximum (FWHM = 3.5 km/s) results in fully resolved line profiles for the highly ionized gas absorption. The measurements provide information on the column density per unit velocity, N(v), as a function of velocity for Si IV, C IV, and N V. The C IV and N V profiles extend from -70 to +70 km/s, while the Si IV profiles extend from -40 to +70 km/s. The integrated logarithmic column densities are long N(Si IV) = 13.09 +/- 0.02, log N(C IV) = 13.83 +/- 0.02, and log N(N V) = 13.56 +/- 0.03. The N V profile is broad, asymmetric, and featureless, while the Si IV profile contains narrow absorption components near V(sub LSR) = -19, 0, +20, and +52 km/s with Doppler spread parameters, b about = 10-12 km/s. The C IV profile contains both broad and narrow structure. The high ion feature near +52 km/s is also detected in the low-ionization lines of Ca II, O I, Si II, and Fe II. The other narrow Si IV and C IV components occur within several km/s of components seen in low-ionization species. The sight line contains at least two types of highly ionized gas. One type gives rise to a broad N V profile, and the other results in the more structured Si IV profile. The C IV profile contains contributions from both types of highly ionized gas. The broad but asymmetric N V profile is well represented by a large Galactic scale height gas which is participating in Galactic rotation and has a combination of thermal and turbulent broadening with b(sub tot) about = 42 km/s. The C IV to N V abundance ratio of 1.0 +/- 0.3 for the gas implies T about 1.6 x 10(exp 5) K or about 8 x 10(exp 5) K if the gas is in collisional ionization equilibrium and has a solar carbon to nitrogen abundance ratio. This absorption may be associated with cooling hot gas situated in Galactic shells and supershells along the sight line. The gas producing the narrow Si IV and C IV absorption components has line widths that are compatible with origins in conductive interfaces between the warm and hot interstellar medium. Kinematic flows associated with the photoionized edges of clouds might also produce Si IV and C IV lines with Doppler spread parameters similar to those observed, but the C IV to Si IV ratio in this gas is 3.5, which leads us to favor the conductive interface interpretation.

Homogeneous Emission Line Broadening in the Organo Lead Halide Perovskite CH3NH3PbI3-xClx.

PubMed

Wehrenfennig, Christian; Liu, Mingzhen; Snaith, Henry J; Johnston, Michael B; Herz, Laura M

2014-04-17

The organic-inorganic hybrid perovskites methylammonium lead iodide (CH3NH3PbI3) and the partially chlorine-substituted mixed halide CH3NH3PbI3-xClx emit strong and broad photoluminescence (PL) around their band gap energy of ∼1.6 eV. However, the nature of the radiative decay channels behind the observed emission and, in particular, the spectral broadening mechanisms are still unclear. Here we investigate these processes for high-quality vapor-deposited films of CH3NH3PbI3-xClx using time- and excitation-energy dependent photoluminescence spectroscopy. We show that the PL spectrum is homogenously broadened with a line width of 103 meV most likely as a consequence of phonon coupling effects. Further analysis reveals that defects or trap states play a minor role in radiative decay channels. In terms of possible lasing applications, the emission spectrum of the perovskite is sufficiently broad to have potential for amplification of light pulses below 100 fs pulse duration.

A Multiwavelength Study of POX 52, a Dwarf Seyfert Galaxy with an Intermediate-Mass Black Hole

NASA Astrophysics Data System (ADS)

Barth, Aaron

2004-07-01

We propose a comprehensive optical, UV, and X-ray investigation of the unique galaxy POX 52. POX 52 is a Seyfert 1 galaxy with unprecedented properties: its host galaxy appears to be a dwarf elliptical, and its stellar velocity dispersion is only 36 km/s. The stellar velocity dispersion and the broad emission-line widths both suggest a black hole mass of order 10^5 solar masses, placing POX 52 in a region of AGN parameter space that is almost completely unexplored at present. We request ACS/HRC imaging to perform a definitive measurement of the host galaxy structure; STIS UV and optical spectroscopy to study the nonstellar continuum and the structure of the broad-line region; and Chandra ACS imaging to detect the X-ray emission from the nucleus and investigate its spectral and variability properties. The results of this program will give a detailed understanding of the host galaxy and accretion properties of one of the very few known black holes in the mass range around 10^5 solar masses.

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

NASA Technical Reports Server (NTRS)

VanDerWel, A.; Straughn, A. N.; Rix, H.-W.; Finkelstein, S. L.; Koekemoer, A. M.; Weiner, B. J.; Wuyts, S.; Bell, E. F.; Faber, S. M.; Trump, J. R.;

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

NASA Technical Reports Server (NTRS)

vanderWel, A.; Straughn, A. N.; Rix, H.-W.; Finkelstein, S. L.; Koekemoer, A. M.; Weiner, B. J.; Wuyts, S.; Bell, E. F.; Faber, S. M.; Trump, J. R.;

Directionality of Flare-Accelerated Particles from γ -ray Lines

NASA Astrophysics Data System (ADS)

Share, G. H.; Murphy, R. J.

2000-05-01

The energies and widths of γ -ray lines emitted by ambient nuclei excited by flare-accelerated protons and α -particles provide information on their directionality, spectra, and on the uniformity of the interaction region. For example, the γ -rays observed from a downward beam of particles impacting at 0o heliocentric angle would exhibit a clear Doppler red-shift and some broadening, dependent on the spectrum of the particles. In contrast, γ -rays observed from the same beam of particles impacting at 90o would be neither observably shifted nor broadened. We have studied the energies and widths of strong lines from de-excitations of 20Ne, 12C, and 16O in solar flares as a function of heliocentric angle. We use spectra from 21 flares observed with NASA's Solar Maximum Mission/GRS and Compton Observatory/OSSE experiments. The line energies of all three nuclei exhibit ~0.9% red-shifts from their laboratory values for flares observed at heliocentric angles <40o. In contrast, the energies are not significantly shifted for flares observed at angles >80o. The lines at all heliocentric angles are broadened between ~2.5% to 4%. These results are suggestive of a broad downward distribution of accelerated particles in flares or an isotropic distribution in a medium that has a significant density gradient. Detailed comparisons of these data with results from the gamma-ray production code (Ramaty, et al. 1979, ApJS, 40, 487; Murphy, et al. 1991, ApJ, 371, 793) are required in order to place constraints on the angular distributions of particles. This research has been supported by NASA grant W-18995.

VizieR Online Data Catalog: CaII in extragalactic red giants (Tolstoy+, 2001)

NASA Astrophysics Data System (ADS)

Tolstoy, E.; Irwin, M. J.; Cole, A. A.; Pasquini, L.; Gilmozzi, R.; Gallagher, J. S.

2002-01-01

Spectroscopic abundance determinations for stars spanning a Hubble time in age are necessary in order to determine unambiguously the evolutionary histories of galaxies. Using FORS1 in multi-object spectroscopy mode on ANTU (UT1) at the ESO VLT on Paranal, we have obtained near-infrared spectra from which we have measured the equivalent widths of the two strongest Ca II triplet lines to determine metal abundances for a sample of red giant branch stars, selected from ESO NTT optical (I, V-I) photometry of three nearby Local Group galaxies: the Sculptor dwarf spheroidal, the Fornax dwarf spheroidal and the dwarf irregular NGC 6822. The summed equivalent width of the two strongest lines in the Ca II triplet absorption-line feature, centred at 8500{AA}, can be readily converted into an [Fe/H] abundance using the previously established calibrations by Armandroff & Da Costa (1991AJ....101.1329A) and Rutledge, Hesser & Stetson (1997, Cat. ). We have measured metallicities for 37 stars in Sculptor, 32 stars in Fornax and 23 stars in NGC 6822, yielding more precise estimates of the metallicity distribution functions for these galaxies than it is possible to obtain photometrically. In the case of NGC 6822, this is the first direct measurement of the abundances of the intermediate-age and old stellar populations. We find metallicity spreads in each galaxy which are broadly consistent with the photometric width of the red giant branch, although the abundances of individual stars do not always appear to correspond to their colour. This is almost certainly predominantly due to a highly variable star formation rate with time in these galaxies, which results in a non-uniform, non-globular-cluster-like evolution of the Ca/Fe ratio. (6 data files).

A Principal Component Analysis of the Diffuse Interstellar Bands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ensor, T.; Cami, J.; Bhatt, N. H.

2017-02-20

We present a principal component (PC) analysis of 23 line-of-sight parameters (including the strengths of 16 diffuse interstellar bands, DIBs) for a well-chosen sample of single-cloud sightlines representing a broad range of environmental conditions. Our analysis indicates that the majority (∼93%) of the variations in the measurements can be captured by only four parameters The main driver (i.e., the first PC) is the amount of DIB-producing material in the line of sight, a quantity that is extremely well traced by the equivalent width of the λ 5797 DIB. The second PC is the amount of UV radiation, which correlates wellmore » with the λ 5797/ λ 5780 DIB strength ratio. The remaining two PCs are more difficult to interpret, but are likely related to the properties of dust in the line of sight (e.g., the gas-to-dust ratio). With our PCA results, the DIBs can then be used to estimate these line-of-sight parameters.« less

Failed Radiatively Accelerated Dusty Outflow Model of the Broad Line Region in Active Galactic Nuclei. I. Analytical Solution

NASA Astrophysics Data System (ADS)

Czerny, B.; Li, Yan-Rong; Hryniewicz, K.; Panda, S.; Wildy, C.; Sniegowska, M.; Wang, J.-M.; Sredzinska, J.; Karas, V.

2017-09-01

The physical origin of the broad line region in active galactic nuclei is still unclear despite many years of observational studies. The reason is that the region is unresolved, and the reverberation mapping results imply a complex velocity field. We adopt a theory-motivated approach to identify the principal mechanism responsible for this complex phenomenon. We consider the possibility that the role of dust is essential. We assume that the local radiation pressure acting on the dust in the accretion disk atmosphere launches the outflow of material, but higher above the disk the irradiation from the central parts causes dust evaporation and a subsequent fallback. This failed radiatively accelerated dusty outflow is expected to represent the material forming low ionization lines. In this paper we formulate simple analytical equations to describe the cloud motion, including the evaporation phase. The model is fully described just by the basic parameters of black hole mass, accretion rate, black hole spin, and viewing angle. We study how the spectral line generic profiles correspond to this dynamic. We show that the virial factor calculated from our model strongly depends on the black hole mass in the case of enhanced dust opacity, and thus it then correlates with the line width. This could explain why the virial factor measured in galaxies with pseudobulges differs from that obtained from objects with classical bulges, although the trend predicted by the current version of the model is opposite to the observed trend.

High-Resolution Graphene Films for Electrochemical Sensing via Inkjet Maskless Lithography.

PubMed

Hondred, John A; Stromberg, Loreen R; Mosher, Curtis L; Claussen, Jonathan C

2017-10-24

Solution-phase printing of nanomaterial-based graphene inks are rapidly gaining interest for fabrication of flexible electronics. However, scalable manufacturing techniques for high-resolution printed graphene circuits are still lacking. Here, we report a patterning technique [i.e., inkjet maskless lithography (IML)] to form high-resolution, flexible, graphene films (line widths down to 20 μm) that significantly exceed the current inkjet printing resolution of graphene (line widths ∼60 μm). IML uses an inkjet printed polymer lacquer as a sacrificial pattern, viscous spin-coated graphene, and a subsequent graphene lift-off to pattern films without the need for prefabricated stencils, templates, or cleanroom technology (e.g., photolithography). Laser annealing is employed to increase conductivity on thermally sensitive, flexible substrates [polyethylene terephthalate (PET)]. Laser annealing and subsequent platinum nanoparticle deposition substantially increases the electroactive nature of graphene as illustrated by electrochemical hydrogen peroxide (H 2 O 2 ) sensing [rapid response (5 s), broad linear sensing range (0.1-550 μm), high sensitivity (0.21 μM/μA), and low detection limit (0.21 μM)]. Moreover, high-resolution, complex graphene circuits [i.e., interdigitated electrodes (IDE) with varying finger width and spacing] were created with IML and characterized via potassium chloride (KCl) electrochemical impedance spectroscopy (EIS). Results indicated that sensitivity directly correlates to electrode feature size as the IDE with the smallest finger width and spacing (50 and 50 μm) displayed the largest response to changes in KCl concentration (∼21 kΩ). These results indicate that the developed IML patterning technique is well-suited for rapid, solution-phase graphene film prototyping on flexible substrates for numerous applications including electrochemical sensing.

Single-epoch black hole mass estimators for broad-line active galactic nuclei: recalibrating Hβ with a new approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, Hua; Li, Hong; Shen, Yue

2014-10-10

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

SN2012ab: a peculiar Type IIn supernova with aspherical circumstellar material

NASA Astrophysics Data System (ADS)

Bilinski, Christopher; Smith, Nathan; Williams, G. Grant; Smith, Paul; Zheng, WeiKang; Graham, Melissa L.; Mauerhan, Jon C.; Andrews, Jennifer E.; Filippenko, Alexei V.; Akerlof, Carl; Chatzopoulos, E.; Hoffman, Jennifer L.; Huk, Leah; Leonard, Douglas C.; Marion, G. H.; Milne, Peter; Quimby, Robert M.; Silverman, Jeffrey M.; Vinkó, Jozsef; Wheeler, J. Craig; Yuan, Fang

2018-03-01

We present photometry, spectra, and spectropolarimetry of supernova (SN) 2012ab, mostly obtained over the course of ˜300 d after discovery. SN 2012ab was a Type IIn (SN IIn) event discovered near the nucleus of spiral galaxy 2MASXJ12224762+0536247. While its light curve resembles that of SN 1998S, its spectral evolution does not. We see indications of CSM interaction in the strong intermediate-width emission features, the high luminosity (peak at absolute magnitude M = -19.5), and the lack of broad absorption features in the spectrum. The Hα emission undergoes a peculiar transition. At early times it shows a broad blue emission wing out to -14 000 km s-1 and a truncated red wing. Then at late times (>100 d) it shows a truncated blue wing and a very broad red emission wing out to roughly +20 000 km s-1. This late-time broad red wing probably arises in the reverse shock. Spectra also show an asymmetric intermediate-width Hα component with stronger emission on the red side at late times. The evolution of the asymmetric profiles requires a density structure in the distant CSM that is highly aspherical. Our spectropolarimetric data also suggest asphericity with a strong continuum polarization of ˜1-3 per cent and depolarization in the Hα line, indicating asphericity in the CSM at a level comparable to that in other SNe IIn. We estimate a mass-loss rate of \\dot{M} = 0.050 M_{⊙} yr^{-1} for vpre = 100 km s-1 extending back at least 75 yr prior to the SN. The strong departure from axisymmetry in the CSM of SN 2012ab may suggest that the progenitor was an eccentric binary system undergoing eruptive mass loss.

Continuous modulations of femtosecond laser-induced periodic surface structures and scanned line-widths on silicon by polarization changes.

PubMed

Han, Weina; Jiang, Lan; Li, Xiaowei; Liu, Pengjun; Xu, Le; Lu, YongFeng

2013-07-01

Large-area, uniform laser-induced periodic surface structures (LIPSS) are of wide potential industry applications. The continuity and processing precision of LIPSS are mainly determined by the scanning intervals of adjacent scanning lines. Therefore, continuous modulations of LIPSS and scanned line-widths within one laser scanning pass are of great significance. This study proposes that by varying the laser (800 nm, 50 fs, 1 kHz) polarization direction, LIPSS and the scanned line-widths on a silicon (111) surface can be continuously modulated with high precision. It shows that the scanned line-width reaches the maximum when the polarization direction is perpendicular to the scanning direction. As an application example, the experiments show large-area, uniform LIPSS can be fabricated by controlling the scanning intervals based on the one-pass scanned line-widths. The simulation shows that the initially formed LIPSS structures induce directional surface plasmon polaritons (SPP) scattering along the laser polarization direction, which strengthens the subsequently anisotropic LIPSS fabrication. The simulation results are in good agreement with the experiments, which both support the conclusions of continuous modulations of the LIPSS and scanned line-widths.

MONTE CARLO SIMULATION OF METASTABLE OXYGEN PHOTOCHEMISTRY IN COMETARY ATMOSPHERES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bisikalo, D. V.; Shematovich, V. I.; Gérard, J.-C.

2015-01-01

Cometary atmospheres are produced by the outgassing of material, mainly H{sub 2}O, CO, and CO{sub 2} from the nucleus of the comet under the energy input from the Sun. Subsequent photochemical processes lead to the production of other species generally absent from the nucleus, such as OH. Although all comets are different, they all have a highly rarefied atmosphere, which is an ideal environment for nonthermal photochemical processes to take place and influence the detailed state of the atmosphere. We develop a Monte Carlo model of the coma photochemistry. We compute the energy distribution functions (EDF) of the metastable O({supmore » 1}D) and O({sup 1}S) species and obtain the red (630 nm) and green (557.7 nm) spectral line shapes of the full coma, consistent with the computed EDFs and the expansion velocity. We show that both species have a severely non-Maxwellian EDF, that results in broad spectral lines and the suprathermal broadening dominates due to the expansion motion. We apply our model to the atmosphere of comet C/1996 B2 (Hyakutake) and 103P/Hartley 2. The computed width of the green line, expressed in terms of speed, is lower than that of the red line. This result is comparable to previous theoretical analyses, but in disagreement with observations. We explain that the spectral line shape does not only depend on the exothermicity of the photochemical production mechanisms, but also on thermalization, due to elastic collisions, reducing the width of the emission line coming from the O({sup 1}D) level, which has a longer lifetime.« less

Minimum line width of ion beam-modified polystyrene by negative carbon ions for nerve-cell attachment and neurite extension

NASA Astrophysics Data System (ADS)

Sommani, P.; Tsuji, H.; Sato, H.; Kitamura, T.; Hattori, M.; Gotoh, Y.; Ishikawa, J.

2007-04-01

The minimum line width of the negative-ion-modified polystyrene (PS) for guidance and immobilizations of nerve-cell body and neurite extension have been investigated. Carbon negative ions were implanted into PS at fluence of 3 × 1015 ions/cm2 and energy of 5-20 keV through the various triangle apertures of the micro-pattern mask. After in vitro culture of the nerve-like cells of rat adrenal pheochromocytoma (PC12h), results showed that the minimum line widths for a single cell attachment and for neurite extension were 5-7 and 3-5 μm, respectively. While the minimum line width for attachment of cell group with long neurite was about 20 μm. The suitable widths for a large number of cells and for neurite extension were 20 and 5 μm, respectively. Therefore, the guidance for a clear separation of the attachment size of cell body and neurite extension could be achieved by the different modified line widths.

Spectral features of tidal disruption candidates and alternative origins for such transient flares

NASA Astrophysics Data System (ADS)

Saxton, Curtis J.; Perets, Hagai B.; Baskin, Alexei

2018-03-01

UV and optically selected candidates for stellar tidal disruption events (TDEs) often exhibit broad spectral features (He II emission, H α emission, or absorption lines) on a blackbody-like continuum (104 K≲ T≲ 105 K). The lines presumably emit from TDE debris or circumnuclear clouds photoionized by the flare. Line velocities however are much lower than expected from a stellar disruption by supermassive black hole (SMBH), and are somewhat faster than expected for the broad line region (BLR) clouds of a persistently active galactic nucleus (AGN). The distinctive spectral states are not strongly related to observed luminosity and velocity, nor to SMBH mass estimates. We use exhaustive photoionization modelling to map the domain of fluxes and cloud properties that yield (e.g.) an He-overbright state where a large He II(4686 Å)/H α line ratio creates an illusion of helium enrichment. Although observed line ratios occur in a plausible minority of cases, AGN-like illumination cannot reproduce the observed equivalent widths. We therefore propose to explain these properties by a light-echo photoionization model: the initial flash of a hot blackbody (detonation) excites BLR clouds, which are then seen superimposed on continuum from a later, expanded, cooled stage of the luminous source. The implied cloud mass is substellar, which may be inconsistent with a TDE. Given these and other inconsistencies with TDE models (e.g. host-galaxies distribution) we suggest to also consider alternative origins for these nuclear flares, which we briefly discuss (e.g. nuclear supernovae and starved/subluminous AGNs).

Line width determination using a biomimetic fly eye vision system.

PubMed

Benson, John B; Wright, Cameron H G; Barrett, Steven F

2007-01-01

Developing a new vision system based on the vision of the common house fly, Musca domestica, has created many interesting design challenges. One of those problems is line width determination, which is the topic of this paper. It has been discovered that line width can be determined with a single sensor as long as either the sensor, or the object in question, has a constant, known velocity. This is an important first step for determining the width of any arbitrary object, with unknown velocity.

Real-time line-width measurements: a new feature for reticle inspection systems

NASA Astrophysics Data System (ADS)

Eran, Yair; Greenberg, Gad; Joseph, Amnon; Lustig, Cornel; Mizrahi, Eyal

1997-07-01

The significance of line width control in mask production has become greater with the lessening of defect size. There are two conventional methods used for controlling line widths dimensions which employed in the manufacturing of masks for sub micron devices. These two methods are the critical dimensions (CD) measurement and the detection of edge defects. Achieving reliable and accurate control of line width errors is one of the most challenging tasks in mask production. Neither of the two methods cited above (namely CD measurement and the detection of edge defects) guarantees the detection of line width errors with good sensitivity over the whole mask area. This stems from the fact that CD measurement provides only statistical data on the mask features whereas applying edge defect detection method checks defects on each edge by itself, and does not supply information on the combined result of error detection on two adjacent edges. For example, a combination of a small edge defect together with a CD non- uniformity which are both within the allowed tolerance, may yield a significant line width error, which will not be detected using the conventional methods (see figure 1). A new approach for the detection of line width errors which overcomes this difficulty is presented. Based on this approach, a new sensitive line width error detector was developed and added to Orbot's RT-8000 die-to-database reticle inspection system. This innovative detector operates continuously during the mask inspection process and scans (inspects) the entire area of the reticle for line width errors. The detection is based on a comparison of measured line width that are taken on both the design database and the scanned image of the reticle. In section 2, the motivation for developing this new detector is presented. The section covers an analysis of various defect types, which are difficult to detect using conventional edge detection methods or, alternatively, CD measurements. In section 3, the basic concept of the new approach is introduced together with a description of the new detector and its characteristics. In section 4, the calibration process that took place in order to achieve reliable and repeatable line width measurements is presented. The description of an experiments conducted in order to evaluate the sensitivity of the new detector is given in section 5, followed by a report of the results of this evaluation. The conclusions are presented in section 6.

THE DUST SUBLIMATION RADIUS AS AN OUTER ENVELOPE TO THE BULK OF THE NARROW Fe Kα LINE EMISSION IN TYPE 1 AGNs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gandhi, Poshak; Hönig, Sebastian F.; Kishimoto, Makoto

2015-10-20

The Fe Kα emission line is the most ubiquitous feature in the X-ray spectra of active galactic nuclei (AGNs), but the origin of its narrow core remains uncertain. Here, we investigate the connection between the sizes of the Fe Kα core emission regions and the measured sizes of the dusty tori in 13 local Type 1 AGNs. The observed Fe Kα emission radii (R{sub Fe}) are determined from spectrally resolved line widths in X-ray grating spectra, and the dust sublimation radii (R{sub dust}) are measured either from optical/near-infrared (NIR) reverberation time lags or from resolved NIR interferometric data. This directmore » comparison shows, on an object-by-object basis, that the dust sublimation radius forms an outer envelope to the bulk of the Fe Kα emission. R{sub Fe} matches R{sub dust} well in the AGNs, with the best constrained line widths currently. In a significant fraction of objects without a clear narrow line core, R{sub Fe} is similar to, or smaller than, the radius of the optical broad line region. These facts place important constraints on the torus geometries for our sample. Extended tori in which the solid angle of fluorescing gas peaks at well beyond the dust sublimation radius can be ruled out. We also test for luminosity scalings of R{sub Fe}, finding that the Eddington ratio is not a prime driver in determining the line location in our sample. We also discuss in detail potential caveats of data analysis and instrumental limitations, simplistic line modeling, uncertain black hole masses, and sample selection, showing that none of these is likely to bias our core result. The calorimeter on board Astro-H will soon vastly increase the parameter space over which line measurements can be made, overcoming many of these limitations.« less

The Mean Metal-line Absorption Spectrum of Damped Ly α Systems in BOSS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mas-Ribas, Lluís; Miralda-Escudé, Jordi; Pérez-Ràfols, Ignasi

We study the mean absorption spectrum of the Damped Ly α (DLA) population at z ∼ 2.6 by stacking normalized, rest-frame-shifted spectra of ∼27,000 DLA systems from the DR12 of the Baryon Oscillation Spectroscopic Survey (BOSS)/SDSS-III. We measure the equivalent widths of 50 individual metal absorption lines in five intervals of DLA hydrogen column density, five intervals of DLA redshift, and overall mean equivalent widths for an additional 13 absorption features from groups of strongly blended lines. The mean equivalent width of low-ionization lines increases with N {sub H} {sub i}, whereas for high-ionization lines the increase is much weaker.more » The mean metal line equivalent widths decrease by a factor ∼1.1–1.5 from z ∼ 2.1 to z ∼ 3.5, with small or no differences between low- and high-ionization species. We develop a theoretical model, inspired by the presence of multiple absorption components observed in high-resolution spectra, to infer mean metal column densities from the equivalent widths of partially saturated metal lines. We apply this model to 14 low-ionization species and to Al iii, S iii, Si iii, C iv, Si iv, N v, and O vi. We use an approximate derivation for separating the equivalent width contributions of several lines to blended absorption features, and infer mean equivalent widths and column densities from lines of the additional species N i, Zn ii, C ii*, Fe iii, and S iv. Several of these mean column densities of metal lines in DLAs are obtained for the first time; their values generally agree with measurements of individual DLAs from high-resolution, high signal-to-noise ratio spectra when they are available.« less

Iron and magnesium in the white dwarf GD 40 - A test of diffusion theory

NASA Technical Reports Server (NTRS)

Shipman, H. L.; Greenstein, J. L.

1983-01-01

An outstanding problem in interpreting the properties of white-dwarf stars is related to the understanding of the chemical abundances in their atmospheres. The hydrogen-rich white-dwarf stars have monoelemental atmospheres, with small quantities of helium and no heavier elements observed in most, possibly all, stars with visible H lines. The helium-rich stars are more complex, and the existence of metallic lines in many of their spectra is now well confirmed. The DB star GD 40 (Gr 384) is the hottest He-rich white-dwarf star to show metal lines, apart from the extremely hot objects, such as HZ 21 and HD 149499B. The present investigation is concerned with IUE spectra which have been obtained of the GD 40. It is found that the near-UV is marked by strong Mg II lines along with broad blends of Fe II lines. An analysis is conducted of the abundances of Fe and Mg at the surface of GD 40 using a limited spectrum-synthesis technique with the measured equivalent widths of the best Fe II features.

Polarized Balmer line emission from supernova remnant shock waves efficiently accelerating cosmic rays

NASA Astrophysics Data System (ADS)

Shimoda, Jiro; Ohira, Yutaka; Yamazaki, Ryo; Laming, J. Martin; Katsuda, Satoru

2018-01-01

Linearly polarized Balmer line emissions from supernova remnant shocks are studied taking into account the energy loss of the shock owing to the production of non-thermal particles. The polarization degree depends on the downstream temperature and the velocity difference between upstream and downstream regions. The former is derived once the line width of the broad component of the H α emission is observed. Then, the observation of the polarization degree tells us the latter. At the same time, the estimated value of the velocity difference independently predicts adiabatic downstream temperature that is derived from Rankine Hugoniot relations for adiabatic shocks. If the actually observed downstream temperature is lower than the adiabatic temperature, there is a missing thermal energy which is consumed for particle acceleration. It is shown that a larger energy-loss rate leads to more highly polarized H α emission. Furthermore, we find that polarized intensity ratio of H β to H α also depends on the energy-loss rate and that it is independent of uncertain quantities such as electron temperature, the effect of Lyman line trapping and our line of sight.

Chromospheric explosions

NASA Technical Reports Server (NTRS)

Doschek, G. A.; theory. (3) Resolved: Most chromospheric h; theory. (3) Resolved: Most chromospheric h

1986-01-01

Three issues relative to chromospheric explosions were debated. (1) Resolved: The blue-shifted components of x-ray spectral lines are signatures of chromospheric evaporation. It was concluded that the plasma rising with the corona is indeed the primary source of thermal plasma observed in the corona during flares. (2) Resolved: The excess line broading of UV and X-ray lines is accounted for by a convective velocity distribution in evaporation. It is concluded that the hypothesis that convective evaporation produces the observed X-ray line widths in flares is no more than a hypothesis. It is not supported by any self-consistent physical theory. (3) Resolved: Most chromospheric heating is driven by electron beams. Although it is possible to cast doubt on many lines of evidence for electron beams in the chromosphere, a balanced view that debaters on both sides of the question might agree to is that electron beams probably heat the low corona and upper chromosphere, but their direct impact on evaporating the chromosphere is energetically unimportant when compared to conduction. This represents a major departure from the thick-target flare models that were popular before the Workshop.

Possible 6-qubit NMR quantum computer device material; simulator of the NMR line width

NASA Astrophysics Data System (ADS)

Hashi, K.; Kitazawa, H.; Shimizu, T.; Goto, A.; Eguchi, S.; Ohki, S.

2002-12-01

For an NMR quantum computer, splitting of an NMR spectrum must be larger than a line width. In order to find a best device material for a solid-state NMR quantum computer, we have made a simulation program to calculate the NMR line width due to the nuclear dipole field by the 2nd moment method. The program utilizes the lattice information prepared by commercial software to draw a crystal structure. By applying this program, we can estimate the NMR line width due to the nuclear dipole field without measurements and find a candidate material for a 6-qubit solid-state NMR quantum computer device.

The effect of lane line width and contrast upon lanekeeping.

PubMed

McKnight, A S; McKnight, A J; Tippetts, A S

1998-09-01

The combined effect of lane line width and line-pavement contrast upon lanekeeping was studied through simulation. Some 124 subjects, ages 17-79 (x = 56.30), 52% male, each performed 42 trials over road segments representing three levels of width crossed with 14 line-pavement contrast ratios. Lanekeeping performance was recorded in terms of heading error, position error, lane excursions and road excursions. Subjects were stratified into two levels of ability on a combined measure of visual, attentional and psychomotor variables known to decline with age. Contrast and width had a negligible effect upon performance except at very low contrast ratios, ca 1.02 at high pavement luminance levels (e.g. concrete) and 1.04 for very low luminance levels (e.g. asphalt). These ratios are similar to those encountered at night on wet roads. Mean overall performance error at the low contrast ratios increased by a factor of 1.6, 1.8 and 2.2 for 8, 6 and 4" widths, respectively. Lower ability subjects exhibited greater error at almost all contrast ratios, with no consistent relationship between degree of decrement and either width or contrast. The results suggest that lane line width and contrast have a negligible effect upon lanekeeping performance except at extremely low levels of contrast, where both have large effects. Further research in the roadway environment is needed to determine the relationships of line width and contrast ratio to lanekeeping on normal and degraded surface conditions.

The characterization of the distant blazar GB6 J1239+0443 from flaring and low activity periods

DOE PAGES

Pacciani, L.; Donnarumma, I.; Denney, K. D.; ...

2012-08-27

In 2008, AGILE and Fermi detected gamma-ray flaring activity from the unidentified EGRET source 3EG J1236+0457, recently associated with a flat spectrum radio quasar (GB6 J1239+0443) at z = 1.762. The optical counterpart of the gamma-ray source underwent a flux enhancement of a factor of 15–30 in six years, and of ~10 in six months. Here, we interpret this flare-up in terms of a transition from an accretion-disc-dominated emission to a synchrotron-jet-dominated one. We analysed a Sloan Digital Sky Survey (SDSS) archival optical spectrum taken during a period of low radio and optical activity of the source. We estimated themore » mass of the central black hole using the width of the C iv emission line. In our work, we have also investigated SDSS archival optical photometric data and ultraviolet GALEX observations to estimate the thermal disc emission contribution of GB6 J1239+0443. This analysis of the gamma-ray data taken during the flaring episodes indicates a flat gamma-ray spectrum, with an extension of up to 15 GeV, with no statistically relevant sign of absorption from the broad-line region, suggesting that the blazar zone is located beyond the broad-line region. Our result is confirmed by the modelling of the broad-band spectral energy distribution (well constrained by the available multiwavelength data) of the flaring activity periods and by the accretion disc luminosity and black hole mass estimated by us using archival data.« less

Long-term Spectral Evolution of Tidal Disruption Candidates Selected by Strong Coronal Lines

NASA Astrophysics Data System (ADS)

Yang, Chen-Wei; Wang, Ting-Gui; Ferland, Gary; Yuan, Weimin; Zhou, Hong-Yan; Jiang, Peng

2013-09-01

We present results of follow-up optical spectroscopic Multi-Mirror Telescope (MMT) observations of seven rare, extreme coronal line-emitting galaxies reported by Wang et al. Large variations in coronal lines are found in four objects, making them strong candidates for tidal disruption events (TDEs). For the four TDE candidates, all the coronal lines with ionization states higher than [Fe VII] disappear within 5-9 yr. The [Fe VII] line faded by a factor of about five in one object (J0952+2143) within 4 yr, whereas the line emerged in another two objects that previously did not show the line. A strong increment in the [O III] flux is observed, shifting the line ratios toward the loci of active galactic nuclei on the BPT diagram. Surprisingly, we detect a non-canonical [O III] λ5007/[O III] λ4959 ratio of ~= 2 in two objects, indicating a large column density of O2 + and thus probably optically thick gas. This result also requires a very large ionization parameter and a relatively soft ionizing spectral energy distribution (e.g., a blackbody with T < 5 × 104 K). Our observations can be explained as the echoing of a strong ultraviolet to soft X-ray flare caused by TDEs on molecular clouds in the inner parsecs of the galactic nuclei. Reanalyzing the Sloan Digital Sky Survey spectra reveals double-peaked or strongly blue-shouldered broad lines in three of the objects, which disappeared in the MMT spectra of two objects and faded by a factor of 10 in 8 yr in the remaining object with a decrease in both the line width and centroid offset. We interpret these broad lines as arising from decelerating biconical outflows. Our results demonstrate that the signatures of echoing can persist for as long as 10 yr and can be used to probe the gas environment in quiescent galactic nuclei.

Neonatal line width in deciduous incisors from Neolithic, mediaeval and modern skeletal samples from north-central Poland.

PubMed

Kurek, Marta; Żądzińska, Elżbieta; Sitek, Aneta; Borowska-Strugińska, Beata; Rosset, Iwona; Lorkiewicz, Wiesław

2016-01-01

The neonatal line is usually the first accentuated incremental line visible on the enamel. The prenatal environment significantly contributes to the width of the neonatal line, influencing the pace of reaching post-delivery homeostasis by the newborn's organism. Studies of the enamel of the earliest developing deciduous teeth can provide an insight into the prenatal development and the perinatal conditions of children of past human populations, thus being an additional source contributing to consideration of the influence of prenatal and perinatal factors modifying growth processes. The aim of this study was to examine whether the neonatal line, reflecting the conditions of the prenatal and perinatal environment, differed between the Neolithic, the mediaeval and the modern populations from the Kujawy region in north-central Poland. The material consisted of longitudinally ground sections of 57 human deciduous incisors obtained from children aged 1.0-7.5 years representing three archaeological series from Brześć Kujawski site. All teeth were sectioned in the labio-linqual plane using a diamond blade (Buechler IsoMet 1000). Final specimens were observed with the microscope Delta Optical Evolution 300 at 10× and 40× magnifications. For each tooth, linear measurements of the neonatal line width were performed on its labial surface at the three levels from the cemento-enamel junction. No significant difference was found in the mean neonatal line width depending on the tooth type and archaeological site, although the thickest neonatal line characterised children from the Neolithic series. In all analysed series, the neonatal line width was diversified depending on the child's age at death. The value of Spearman's rank correlation coefficient calculated for the correlation between the child's age at death and the neonatal line width was statistically significant. A clear increase in the width of the neonatal line was thus observed along with a decrease in the child's age at death. Copyright © 2015 Elsevier GmbH. All rights reserved.

Electron Stark Broadening Database for Atomic N, O, and C Lines

NASA Technical Reports Server (NTRS)

Liu, Yen; Yao, Winifred M.; Wray, Alan A.; Carbon, Duane F.

2012-01-01

A database for efficiently computing the electron Stark broadening line widths for atomic N, O, and C lines is constructed. The line width is expressed in terms of the electron number density and electronatom scattering cross sections based on the Baranger impact theory. The state-to-state cross sections are computed using the semiclassical approximation, in which the atom is treated quantum mechanically whereas the motion of the free electron follows a classical trajectory. These state-to-state cross sections are calculated based on newly compiled line lists. Each atomic line list consists of a careful merger of NIST, Vanderbilt, and TOPbase line datasets from wavelength 50 nm to 50 micrometers covering the VUV to IR spectral regions. There are over 10,000 lines in each atomic line list. The widths for each line are computed at 13 electron temperatures between 1,000 K 50,000 K. A linear least squares method using a four-term fractional power series is then employed to obtain an analytical fit for each line-width variation as a function of the electron temperature. The maximum L2 error of the analytic fits for all lines in our line lists is about 5%.

Disparity of spectral behavior of RR Tel and RX Pup in the UV

NASA Astrophysics Data System (ADS)

Sanad, M. R.

2010-07-01

The main aim of this study is to use archival low-dispersion spectra from the International Ultraviolet Explorer (IUE) in an attempt to follow up the spectral behavior of two symbiotic Mira systems RR Tel and RX Pup of the period from 1978-1995 and 1979-1989 for two systems respectively. We concentrated on studying N IV 1486 Å intercombination line, coming from the emission nebulae ( Bryan and Kwok, 1991; Muerset et al., 1991; Murset and Nussbaumer, 1994), by calculating the line fluxes and line widths of N IV 1486 Å. We found that there is a disparity of spectral variability for these physical parameters at different times for both systems. For RR Tel, both line fluxes and line widths are increasing with the phase, while for RX Pup, both line fluxes and line widths are decreasing with the phase. There is a relation between the parameters of this emission line (line flux, line width) and phase, which we attribute to the variations of temperature of the emission nebulae at different times, as a result of the activity of the hot component.

Failed Radiatively Accelerated Dusty Outflow Model of the Broad Line Region in Active Galactic Nuclei. I. Analytical Solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Czerny, B.; Panda, S.; Wildy, C.

2017-09-10

The physical origin of the broad line region in active galactic nuclei is still unclear despite many years of observational studies. The reason is that the region is unresolved, and the reverberation mapping results imply a complex velocity field. We adopt a theory-motivated approach to identify the principal mechanism responsible for this complex phenomenon. We consider the possibility that the role of dust is essential. We assume that the local radiation pressure acting on the dust in the accretion disk atmosphere launches the outflow of material, but higher above the disk the irradiation from the central parts causes dust evaporationmore » and a subsequent fallback. This failed radiatively accelerated dusty outflow is expected to represent the material forming low ionization lines. In this paper we formulate simple analytical equations to describe the cloud motion, including the evaporation phase. The model is fully described just by the basic parameters of black hole mass, accretion rate, black hole spin, and viewing angle. We study how the spectral line generic profiles correspond to this dynamic. We show that the virial factor calculated from our model strongly depends on the black hole mass in the case of enhanced dust opacity, and thus it then correlates with the line width. This could explain why the virial factor measured in galaxies with pseudobulges differs from that obtained from objects with classical bulges, although the trend predicted by the current version of the model is opposite to the observed trend.« less

Note: Broadly tunable all-fiber ytterbium laser with 0.05 nm spectral width based on multimode interference filter.

PubMed

Mukhopadhyay, Pranab K; Gupta, Pradeep K; Singh, Amarjeet; Sharma, Sunil K; Bindra, Kushvinder S; Oak, Shrikant M

2014-05-01

A multimode interference filter with narrow transmission bandwidth and large self-imaging wavelength interval is constructed and implemented in an ytterbium doped fiber laser in all-fiber format for broad wavelength tunability as well as narrow spectral width of the output beam. The peak transmission wavelength of the multimode interference filter was tuned with the help of a standard in-fiber polarization controller. With this simple mechanism more than 30 nm (1038 nm-1070 nm) tuning range is demonstrated. The spectral width of the output beam from the laser was measured to be 0.05 nm.

Note: Broadly tunable all-fiber ytterbium laser with 0.05 nm spectral width based on multimode interference filter

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Pranab K.; Gupta, Pradeep K.; Singh, Amarjeet; Sharma, Sunil K.; Bindra, Kushvinder S.; Oak, Shrikant M.

2014-05-01

A multimode interference filter with narrow transmission bandwidth and large self-imaging wavelength interval is constructed and implemented in an ytterbium doped fiber laser in all-fiber format for broad wavelength tunability as well as narrow spectral width of the output beam. The peak transmission wavelength of the multimode interference filter was tuned with the help of a standard in-fiber polarization controller. With this simple mechanism more than 30 nm (1038 nm-1070 nm) tuning range is demonstrated. The spectral width of the output beam from the laser was measured to be 0.05 nm.

Note: Broadly tunable all-fiber ytterbium laser with 0.05 nm spectral width based on multimode interference filter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mukhopadhyay, Pranab K., E-mail: pkm@rrcat.gov.in; Gupta, Pradeep K.; Singh, Amarjeet

2014-05-15

A multimode interference filter with narrow transmission bandwidth and large self-imaging wavelength interval is constructed and implemented in an ytterbium doped fiber laser in all-fiber format for broad wavelength tunability as well as narrow spectral width of the output beam. The peak transmission wavelength of the multimode interference filter was tuned with the help of a standard in-fiber polarization controller. With this simple mechanism more than 30 nm (1038 nm–1070 nm) tuning range is demonstrated. The spectral width of the output beam from the laser was measured to be 0.05 nm.

Determination of natural line widths of Kα X-ray lines for some elements in the atomic range 50≤Z≤65 at 59.5 keV

NASA Astrophysics Data System (ADS)

Kündeyi, Kadriye; Aylıkcı, Nuray Küp; Tıraşoǧlu, Engin; Kahoul, Abdelhalim; Aylıkcı, Volkan

2017-02-01

The semi-empirical determination of natural widths of Kα X-ray lines (Kα1 and Kα2) were performed for Sn, Sb, Te, I, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd and Tb. For the semi-empirical determination of the line widths, K shell fluorescence yields of elements were measured. The samples were excited by 59.5 keV γ rays from a 241Am annular radioactive source in order to measure the K shell fluorescence yields. The emitted K X-rays from the samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The measured K shell fluorescence yields were used for the calculation of K shell level widths. Finally, the natural widths of K X-ray lines were determined as the sums of levels which involved in the transition. The obtained values were compared with earlier studies.

Interaction Between the Broad-Lined Type Ic Supernova 2012ap and Carriers of Diffuse Interstellar Bands

NASA Technical Reports Server (NTRS)

Milisavljevic, Dan; Margutti, Raffaella; Crabtree, Kyle N.; Foster, Jonathan B.; Soderberg, Alicia M.; Fesen, Robert A.; Parrent, Jerod T.; Sanders, Nathan E.; Drout, Maria R.; Kamble, Atish;

Ultraviolet Properties of Halo Coronal Mass Ejections: Doppler Shifts, Angles, Shocks, and Bulk Morphology

NASA Astrophysics Data System (ADS)

Ciaravella, A.; Raymond, J. C.; Kahler, S. W.

2006-11-01

We present UV spectral information for 22 halo or partial halo CMEs observed by UVCS. The CME fronts show broad line profiles, while the line intensities are comparable to the background corona. The Doppler shifts of the front material are generally small, showing that the motion of gas in the fronts is mostly transverse to the line of sight. This indicates that, at least in halo CMEs, the fronts generally correspond to coronal plasma swept up by a shock or compression wave, rather than plasma carried outward by magnetic loops. This favors an ice cream cone (or a spherical shell) model, as opposed to an expanding arcade of loops. We use the line widths to discriminate between shock heating and bulk expansion. Of 14 cases where we detected the CME front, the line broadening in 7 cases can be attributed to shock heating, while in 3 cases it is the line-of-sight component of the CME expansion. For the CME cores we determine the angles between the motion and the plane of the sky, along with the actual heliocentric distances, in order to provide quantitative estimates of projection effects.

Line shape parameters of PH3 transitions in the Pentad near 4-5 μm: Self-broadened widths, shifts, line mixing and speed dependence

NASA Astrophysics Data System (ADS)

Malathy Devi, V.; Benner, D. Chris; Kleiner, Isabelle; Sams, Robert L.; Fletcher, Leigh N.

2014-08-01

Accurate knowledge of spectroscopic line parameters of PH3 is important for remote sensing of the outer planets, especially Jupiter and Saturn. In a recent study, line positions and intensities for the Pentad bands of PH3 have been reported from analysis of high-resolution, high signal-to noise room-temperature spectra recorded with two Fourier transform spectrometers (2014) [1]. The results presented in this study were obtained during the analysis of positions and intensities, but here we focus on the measurements of spectral line shapes (e.g. widths, shifts, line mixing) for the 2ν4, ν2 + ν4, ν1 and ν3 bands. A multispectrum nonlinear least squares curve fitting technique employing a non-Voigt line shape to include line mixing and speed dependence of the Lorentz width was employed to fit the spectra simultaneously. The least squares fittings were performed on five room-temperature spectra recorded at various PH3 pressures (∼2-50 Torr) with the Bruker IFS-125HR Fourier transform spectrometer (FTS) located at the Pacific Northwest National Laboratory (PNNL), in Richland, Washington. Over 840 Lorentz self-broadened half-width coefficients, 620 self-shift coefficients and 185 speed dependence parameters were measured. Line mixing was detected for transitions in the 2ν4, ν1 and ν3 bands, and their values were quantified for 10 A+A- pairs of transitions via off-diagonal relaxation matrix element formalism. The dependences of the measured half-width coefficients on the J and K rotational quanta of the transitions are discussed. The self-width coefficients for the ν1 and ν3 bands from this study are compared to the self-width coefficients for transitions with the same rotational quanta (J, K) reported for the Dyad (ν2 and ν4) bands. The measurements from present study should be useful for the development of a reliable theoretical modeling of pressure-broadened widths, shifts and line mixing in symmetric top molecules with C3v symmetry in general, and of PH3 in particular.

Line shape parameters of PH 3 transitions in the Pentad near 4–5 μm: Self-broadened widths, shifts, line mixing and speed dependence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malathy Devi, V.; Benner, D. C.; Kleiner, Isabelle

2014-08-01

Accurate knowledge of spectroscopic line parameters of PH 3 is important for remote sensing of the outer planets, especially Jupiter and Saturn. In a recent study, line positions and intensities for the Pentad bands of PH 3 have been reported from analysis of high-resolution, high signal-to noise room-temperature spectra recorded with two Fourier transform spectrometers (2014) [1]. The results presented in this study were obtained during the analysis of positions and intensities, but here we focus on the measurements of spectral line shapes (e.g. widths, shifts, line mixing) for the 2ν 4, ν 2 + ν 4, ν 1 andmore » ν 3 bands. A multispectrum nonlinear least squares curve fitting technique employing a non-Voigt line shape to include line mixing and speed dependence of the Lorentz width was employed to fit the spectra simultaneously. The least squares fittings were performed on five room-temperature spectra recorded at various PH 3 pressures (~2–50 Torr) with the Bruker IFS-125HR Fourier transform spectrometer (FTS) located at the Pacific Northwest National Laboratory (PNNL), in Richland, Washington. Over 840 Lorentz self-broadened half-width coefficients, 620 self-shift coefficients and 185 speed dependence parameters were measured. Line mixing was detected for transitions in the 2ν 4, ν 1 and ν 3 bands, and their values were quantified for 10 A+A- pairs of transitions via off-diagonal relaxation matrix element formalism. The dependences of the measured half-width coefficients on the J and K rotational quanta of the transitions are discussed. The self-width coefficients for the ν 1 and ν 3 bands from this study are compared to the self-width coefficients for transitions with the same rotational quanta (J, K) reported for the Dyad (ν 2 and ν 4) bands. The measurements from present study should be useful for the development of a reliable theoretical modeling of pressure-broadened widths, shifts and line mixing in symmetric top molecules with C 3v symmetry in general, and of PH 3 in particular.« less

Coincidences between O VI and O VII Lines: Insights from High-resolution Simulations of the Warm-hot Intergalactic Medium

NASA Astrophysics Data System (ADS)

Cen, Renyue

2012-07-01

With high-resolution (0.46 h -1 kpc), large-scale, adaptive mesh-refinement Eulerian cosmological hydrodynamic simulations we compute properties of O VI and O VII absorbers from the warm-hot intergalactic medium (WHIM) at z = 0. Our new simulations are in broad agreement with previous simulations with ~40% of the intergalactic medium being in the WHIM. Our simulations are in agreement with observed properties of O VI absorbers with respect to the line incidence rate and Doppler-width-column-density relation. It is found that the amount of gas in the WHIM below and above 106 K is roughly equal. Strong O VI absorbers are found to be predominantly collisionally ionized. It is found that (61%, 57%, 39%) of O VI absorbers of log N(O VI) cm2 = (12.5-13, 13-14, > 14) have T < 105 K. Cross correlations between galaxies and strong [N(O VI) > 1014 cm-2] O VI absorbers on ~100-300 kpc scales are suggested as a potential differentiator between collisional ionization and photoionization models. Quantitative prediction is made for the presence of broad and shallow O VI lines that are largely missed by current observations but will be detectable by Cosmic Origins Spectrograph observations. The reported 3σ upper limit on the mean column density of coincidental O VII lines at the location of detected O VI lines by Yao et al. is above our predicted value by a factor of 2.5-4. The claimed observational detection of O VII lines by Nicastro et al., if true, is 2σ above what our simulations predict.

QSO Broad Emission Line Asymmetries: Evidence of Gravitational Redshift?

NASA Astrophysics Data System (ADS)

Corbin, Michael R.

1995-07-01

The broad optical and ultraviolet emission lines of QSOs and active galactic nuclei (AGNs) display both redward and blueward asymmetries. This result is particularly well established for Hβ and C IV λ1549, and it has been found that Hβ becomes increasingly redward asymmetric with increasing soft X-ray luminosity. Two models for the origin of these asymmetries are investigated: (1) Anisotropic line emission from an ensemble of radially moving clouds, and (2) Two-component profiles consisting of a core of intermediate (˜1000-4000 km s-1) velocity width and a very broad (˜5000-20,000 km s-1) base, in which the asymmetries arise due to a velocity difference between the centroids of the components. The second model is motivated by the evidence that the traditional broad-line region is actually composed of an intermediate-line region (ILR) of optically thick clouds and a very broad line region (VBLR) of optically thin clouds lying closer to the central continuum source. Line profiles produced by model (1) are found to be inconsistent with those observed, being asymmetric mainly in their cores, whereas the asymmetries of actual profiles arise mainly from excess emission in their wings. By contrast, numerical fitting to actual Hβ and C IV λ1549 line profiles reveals that the majority can be accurately modeled by two components, either two Gaussians or the combination of a Gaussian base and a logarithmic core. The profile asymmetries in Hβ can be interpreted as arising from a shift of the base component over a range ˜6300 km s-1 relative to systemic velocity as defined by the position of the [O III] λ5007 line. A similar model appears to apply to C IV λ1549. The correlation between Hβ asymmetry and X-ray luminosity may thus be interpreted as a progressive red- shift of the VBLR velocity centroid relative to systemic velocity with increasing X-ray luminosity. This in turn suggests that the underlying effect is gravitational red shift, as soft X-ray emission arises from a region ˜ light-minutes in size and arguably traces the mass of the putative supermassive black hole. Depending on the size of the VBLR and the exact amount of its profile centroid shift, central masses in the range 109-10 Msun are implied for the objects displaying the strongest redward profile asymmetries, consistent with other estimates. The largest VBLR velocity dispersions measured from the two-component modeling are ˜20,000 km s-1, which also yields a virial mass ˜109 Msun for a VBLR size 0.1 pc. The gravitational redshift model does not explain the origin of the blueshift of the VBLR emission among low X-ray luminosity sources, however. This must be interpreted as arising from a competing effect such as electron scattering of line photons in the vicinity of the VBLR. On average, radio-loud objects have redward asymmetric broad-line profiles and stronger intermediate- and narrow-line emission than radio-quiet objects of comparable optical luminosity. Under the gravitational redshift model these differences may be interpreted as the result of black hole and host galaxy masses that are larger on average among the former class, consistent with the evidence that they are merger products.

What Fraction of Active Galaxies Actually Show Outflows?

NASA Astrophysics Data System (ADS)

Ganguly, Rajib; Brotherton, M. S.

2007-12-01

Outflows from active galactic nuclei (AGNs) seem to be common and are thought to be important from a variety of perspectives: as an agent of chemical enhancement of the interstellar and intergalactic media, as an agent of angular momentum removal from the accreting central engine, and as an agent limiting star formation in starbursting systems by blowing out gas and dust from the host galaxy. To understand these processes, we must determine what fraction of AGNs feature outflows and understand what forms they take. We examine recent surveys of outflows detected in ultraviolet absorption over the entire range of velocities and velocity widths (i.e., broad absorption lines, associated absorption lines, and high-velocity narrow absorption lines). While the fraction of specific forms of outflows depends on AGN properties, the overall fraction displaying outflows is fairly constant, approximately 60%, over many orders of magnitude in luminosity. We discuss implications of this result and ways to refine our understanding of outflows. We acknowledge support from the US National Science Foundation through grant AST 05-07781.

Electron spectroscopic determinations of M and N core-hole lifetimes for the elements Nb-Te (Z=41-52)

NASA Astrophysics Data System (ADS)

Mårtensson, Nils; Nyholm, Ralf

1981-12-01

Photoelectron spectroscopy has been used to determine M and N core-level widths for the elements Nb-Te (Z=41-52). The analysis is based on direct comparisons of the lifetime contributions to different core levels. Absolute determinations are made for the narrow 3d levels. In the metals Nb-Rh (Z=41-45) an M4M5N45 Coster-Kronig decay channel is observed through a broadening of the 3d32 core-electron lines. The rate of this Coster-Kronig process is found to have its maximum for Ru and Rh. For Pd a much reduced, but still significant, broadening of the 3d32 level is detected. This observation is discussed in terms of itinerant versus quasiatomic contributions to the Coster-Kronig process. For Z>=47 (Ag) the Coster-Kronig channel is closed. For Nb-Rh the M4M5N45 process can be used for absolute determinations of the 3d linewidths. In this connection also the properties of the M45N45N45 Auger process are discussed. The accuracy of the present method makes it possible to investigate small differences between the 3p12 and 3p32 level widths. For several elements the unusual result is obtained that the 3p32 level is broader than the 3p12 level. This finding is in good agreement with theoretical predictions. The 4s and 4p spectra of the currently investigated elements are strongly influenced by configuration-interaction (CI) effects. However, the 4s line shapes are found to be quite normal for all the 5th-period elements. For Z<=45 (Rh) the 4p12 level is found to be broadened due to N2N3N45 super-Coster-Kronig processes. For Z<=46 (Pd) the shape of the 4p32 core-electron lines can reasonably well be reproduced by broadened 3d52 line profiles. For Z>=47 (Ag) this can, however, not be achieved. This marks a transition into a region of Z values where CI effects become particularly important. The accuracy of the present method for determining core-level widths can be judged from a comparison between our analysis of the 4p levels and x-ray studies of the Mζ transition. The results indicate that core-level widths can be determined with an accuracy of about 0.2 eV even for fairly broad and asymmetric electron lines.

Laboratory measurements of VUV N2 photoabsorption cross sections and line widths: applications to planetary atmospheric transmission models

NASA Astrophysics Data System (ADS)

Smith, P. L.; Stark, G.; Yoshino, K.

2003-05-01

The analyses of VUV occultation measurements of the N2-rich atmospheres of Titan and Triton are hampered by the lack of fundamental spectroscopic data for N2. There is a need for reliable photoabsorption cross sections and line widths for the 100 electronic bands of N2 in the 80 to 100 nm wavelength region. We present analyses of new measurements of individual line strengths and widths in N2 bands in the region 94 to 100 nm. Within individual bands, we find significant departures from the predicted line strength distributions based on isolated band models. Line width analyses within each band indicate that predissociation-broadening is often highly dependent on the rotational quantum number. We illustrate the importance of N2 line widths in the analysis of occultation measurements via N2 transmission models over selected wavelength regions. We have continued to compile on-line molecular spectroscopic atlas based on our N2 laboratory data: http://cfa-www.harvard.edu/amdata/ampdata/N2ARCHIVE/n2home.html. The archive includes published and unpublished 14N2, 14N15N, and 15N2 line lists and spectroscopic identifications, excited state energy levels, band and line f-values, a summary of published band f-value and line width measurements, and a cross-referenced summary of the relevant N2 literature. The listings are searchable by wavelength interval or band identification and are suitable for down-loading in a convenient format. We gratefully acknowledge funding support from NASA grant NAG5-9059 and the Smithsonian Institution Atherton-Seidell Grant Program.

QSO Emission Lines and the Black Hole-Galaxy Bulge Relation

NASA Astrophysics Data System (ADS)

Shields, G. A.; Gebhardt, K.; Salviander, S.; Wills, B. J.; Yuan, M.; Xie, B.; Dietrich, M.

2002-05-01

Supermassive black holes in galactic nuclei have masses closely related to the properties of the host galaxy bulge. In particular, MBH varies as the fourth power of σ , the stellar velocity dispersion (Tremaine et al. 2002, ApJ in press, and references therein). The origin of the black hole-bulge relation is unknown, although theoretical suggestions abound. An important clue would be provided by knowledge of how the relation has evolved over cosmic time. This requires measurement of black hole masses and galactic potentials at large look-back times, which is difficult to do directly. However, black hole masses may be derived from the continuum luminosity and the widths of the broad Balmer lines of QSOs (e.g., Kaspi et al. 2000, ApJ 533, 631), and σ may be derived from the widths of the narrow [O III] lines (Nelson 2000, ApJ, 544, L91). We have carried out this program for a set of published and unpublished observations of Seyfert galaxies and QSOs. Results for low redshift objects support the use of this method to derive MBH and σ . The few available measurements of high redshift QSOs are consistent little or no change in the MBH-σ relation between the present and redshifts up to z = 3.3, when the universe was only two billion years old. This material is based in part upon work supported by the Texas Advanced Research Program under Grant No. 003658-0177-2001.

Multiwavelength observations of the binary system PSR B1259-63/LS 2883 around the 2010-2011 periastron passage

DOE PAGES

Chernyakova, M.; Abdo, A. A.; Neronov, A.; ...

2014-01-30

Here, we report on broad multiwavelength observations of the 2010–2011 periastron passage of the γ-ray loud binary system PSR B1259-63. High-resolution interferometric radio observations establish extended radio emission trailing the position of the pulsar. Observations with the FermiGamma-ray Space Telescope reveal GeV γ-ray flaring activity of the system, reaching the spin-down luminosity of the pulsar, around 30 d after periastron. Furthermore, there are no clear signatures of variability at radio, X-ray and TeV energies at the time of the GeV flare. Variability around periastron in the Hα emission line, can be interpreted as the gravitational interaction between the pulsar andmore » the circumstellar disc. The equivalent width of the Hα grows from a few days before periastron until a few days later, and decreases again between 18 and 46 d after periastron. In near-infrared we observe the similar decrease of the equivalent width of Brγ line between the 40th and 117th day after the periastron. For the idealized disc, the variability of the Hα line represents the variability of the mass and size of the disc. Finally, we discuss possible physical relations between the state of the disc and GeV emission under assumption that GeV flare is directly related to the decrease of the disc size.« less

Broadband supercontinuum generation with femtosecond pulse width in erbium-doped fiber laser (EDFL)

NASA Astrophysics Data System (ADS)

Rifin, S. N. M.; Zulkifli, M. Z.; Hassan, S. N. M.; Munajat, Y.; Ahmad, H.

2016-11-01

We demonstrate two flat plateaus and the low-noise spectrum of supercontinuum generation (SCG) in a highly nonlinear fiber (HNLF), injected by an amplified picosecond pulse seed of a carbon nanotube-based passively mode locked erbium-doped fiber laser. A broad spectrum of width approximately 1090 nm spanning the range 1130-2220 nm is obtained and the pulse width is compressed to the shorter duration of 70 fs. Variations of the injected peak power up to 33.78 kW into the HNLF are compared and the broad spectrum SCG profiles slightly expand for each of the injected peak powers. This straightforward configuration of SCG offers low output power and ultra-narrow femtosecond pulse width. The results facilitate the development of all fiber time-domain spectroscopy systems based on the photoconductive antenna technique.

Folded inflatable protective device and method for making same

DOEpatents

Behr, V.L.; Nelsen, J.M.; Gwinn, K.W.

1998-10-20

An apparatus and method are disclosed for making an inflatable protective device made of lightweight material that can withstand the initial stress from inflation and enhance radial inflation. The device includes a cushion and an inflator port. The invention further includes several stacks of folded cushion material including a combination of full-width stacks and half-width stacks: a first full-width stack defined by one or more fan folds in a first lateral half of the cushion wherein the folds are substantially centered above a first center line and are substantially over the inflator port; a second full-width stack defined by one or more fan folds in a second lateral half of the cushion wherein the folds are substantially centered above the first center line and substantially over the inflator port in the first full-width stack; a first half-width stack defined by a plurality of fan folds in the bottom of the cushion where neither edge of each fold extends substantially over the second center line; and a second half-width stack defined by a plurality of fan folds in the top of the cushion wherein neither edge of each fold extends substantially over the second center line. 22 figs.

Folded inflatable protective device and method for making same

DOEpatents

Behr, Vance L.; Nelsen, James M.; Gwinn, Kenneth W.

1998-01-01

An apparatus and method for making an inflatable protective device made of lightweight material that can withstand the initial stress from inflation and enhance radial inflation. The device includes a cushion and an inflator port. The invention further includes several stacks of folded cushion material including a combination of full-width stacks and half-width stacks: a first full-width stack defined by one or more fan folds in a first lateral half of the cushion wherein the folds are substantially centered above a first center line and are substantially over the inflator port; a second full-width stack defined by one or more fan folds in a second lateral half of the cushion wherein the folds are substantially centered above the first center line and substantially over the inflator port in the first full-width stack; a first half-width stack defined by a plurality of fan folds in the bottom of the cushion where neither edge of each fold extends substantially over the second center line; and a second half-width stack defined by a plurality of fan folds in the top of the cushion wherein neither edge of each fold extends substantially over the second center line.

Femtosecond soliton source with fast and broad spectral tunability.

PubMed

Masip, Martin E; Rieznik, A A; König, Pablo G; Grosz, Diego F; Bragas, Andrea V; Martinez, Oscar E

2009-03-15

We present a complete set of measurements and numerical simulations of a femtosecond soliton source with fast and broad spectral tunability and nearly constant pulse width and average power. Solitons generated in a photonic crystal fiber, at the low-power coupling regime, can be tuned in a broad range of wavelengths, from 850 to 1200 nm using the input power as the control parameter. These solitons keep almost constant time duration (approximately 40 fs) and spectral widths (approximately 20 nm) over the entire measured spectra regardless of input power. Our numerical simulations agree well with measurements and predict a wide working wavelength range and robustness to input parameters.

Application of the Hartmann-Tran profile to analysis of H2O spectra

NASA Astrophysics Data System (ADS)

Lisak, D.; Cygan, A.; Bermejo, D.; Domenech, J. L.; Hodges, J. T.; Tran, H.

2015-10-01

The Hartmann-Tran profile (HTP), which has been recently recommended as a new standard in spectroscopic databases, is used to analyze spectra of several lines of H2O diluted in N2, SF6, and in pure H2O. This profile accounts for various mechanisms affecting the line-shape and can be easily computed in terms of combinations of the complex Voigt profile. A multi-spectrum fitting procedure is implemented to simultaneously analyze spectra of H2O transitions acquired at different pressures. Multi-spectrum fitting of the HTP to a theoretical model confirms that this profile provides an accurate description of H2O line-shapes in terms of residuals and accuracy of fitted parameters. This profile and its limiting cases are also fit to measured spectra for three H2O lines in different vibrational bands. The results show that it is possible to obtain accurate HTP line-shape parameters when measured spectra have a sufficiently high signal-to-noise ratio and span a broad range of collisional-to-Doppler line widths. Systematic errors in the line area and differences in retrieved line-shape parameters caused by the overly simplistic line-shape models are quantified. Also limitations of the quadratic speed-dependence model used in the HTP are demonstrated in the case of an SF6 broadened H2O line, which leads to a strongly asymmetric line-shape.

A molecular gas-rich GRB host galaxy at the peak of cosmic star formation

NASA Astrophysics Data System (ADS)

Arabsalmani, M.; Le Floc'h, E.; Dannerbauer, H.; Feruglio, C.; Daddi, E.; Ciesla, L.; Charmandaris, V.; Japelj, J.; Vergani, S. D.; Duc, P.-A.; Basa, S.; Bournaud, F.; Elbaz, D.

2018-05-01

We report the detection of the CO(3-2) emission line from the host galaxy of gamma-ray burst (GRB) 080207 at z = 2.086. This is the first detection of molecular gas in emission from a GRB host galaxy beyond redshift 1. We find this galaxy to be rich in molecular gas with a mass of 1.1 × 10^{11} M_{{\\odot }} assuming αCO = 4.36 M_{{\\odot }} (K km s^{-1} pc^2)^{-1}. The molecular gas mass fraction of the galaxy is ˜0.5, typical of star-forming galaxies (SFGs) with similar stellar masses and redshifts. With an SFR_{FIR} of 260 M_{{\\odot }} yr^{-1}, we measure a molecular gas depletion time-scale of 0.43 Gyr, near the peak of the depletion time-scale distribution of SFGs at similar redshifts. Our findings are therefore in contradiction with the proposed molecular gas deficiency in GRB host galaxies. We argue that the reported molecular gas deficiency for GRB hosts could be the artefact of improper comparisons or neglecting the effect of the typical low metallicities of GRB hosts on the CO-to-molecular-gas conversion factor. We also compare the kinematics of the CO(3-2) emission line to that of the H α emission line from the host galaxy. We find the H α emission to have contributions from two separate components, a narrow and a broad one. The narrow component matches the CO emission well in velocity space. The broad component, with a full width at half-maximum of ˜1100 km s^{-1}, is separated by +390 km s^{-1} in velocity space from the narrow component. We speculate this broad component to be associated with a powerful outflow in the host galaxy or in an interacting system.

Shock-tube studies of atomic silicon emission in the spectral range 180 to 300 nm. [environment simulation for Jupiter probes

NASA Technical Reports Server (NTRS)

Prakash, S. G.; Park, C.

1978-01-01

Emission spectroscopy of shock-heated atomic silicon was performed in the spectral range 180 to 300 nm, in an environment simulating the ablation layer expected around a Jovian entry probe with a silica heat shield. From the spectra obtained at temperatures from 6000 to 10,000 K and electron number densities from 1 quadrillion to 100 quadrillion per cu cm, the Lorentzian line-widths were determined. The results showed that silicon lines are broadened significantly by both electrons (Stark broadening) and hydrogen atoms (Van der Waals broadening), and the combined line-widths are much larger than previously assumed. From the data, the Stark and the Van der Waals line-widths were determined for 34 silicon lines. Radiative transport through a typical shock layer was computed using the new line-width data. The computations showed that silicon emission in the hot region is large, but it is mostly absorbed in the colder region adjacent to the wall.

SMM observations of gamma-ray transients. 2: A search for gamma-ray lines between 400 and 600 keV from the Crab Nebula

NASA Technical Reports Server (NTRS)

Harris, Michael J.; Share, Gerald H.; Leising, Mark D.

1994-01-01

We have search spectra obtained by the Solar Maximum Mission Gamma-Ray Spectrometer during 1981-1988 for evidence of transient gamma-ray lines from the Crab Nebula which have been reported by previous experiments at energies 400-460 keV and 539 keV. We find no evidence for significant emission in any of these lines on time scales between aproximately 1 day and approximately 1 yr. Our 3 sigma upper limits on the transient flux during 1 d intervals are approximately equal to 2.2 x 10(exp -3) photons/sq cm/s for narrow lines at any energy, and approximately equal to 2.9 x 10(exp -3) photons/sq cm/s for the 539 keV line if it is as broad as 42 keV Full Width at Half Maximum (FWHM). We also searched our data during the approximately 5 hr period on 1981 June 6 during which Owens, Myers, & Thompson (1985) reported a strong line at 405 keV. We detected no line down to a 3 upper sigma limit of 3.3 x 10(exp -3) photons/sq cm/s in disagreement with the flux 7.2 +/- 2.1 x 10(exp -3) photos/sq cm/s measured by Owens et al.

Voigt equivalent widths and spectral-bin single-line transmittances: Exact expansions and the MODTRAN®5 implementation

NASA Astrophysics Data System (ADS)

Berk, Alexander

2013-03-01

Exact expansions for Voigt line-shape total, line-tail and spectral bin equivalent widths and for Voigt finite spectral bin single-line transmittances have been derived in terms of optical depth dependent exponentially-scaled modified Bessel functions of integer order and optical depth independent Fourier integral coefficients. The series are convergent for the full range of Voigt line-shapes, from pure Doppler to pure Lorentzian. In the Lorentz limit, the expansion reduces to the Ladenburg and Reiche function for the total equivalent width. Analytic expressions are derived for the first 8 Fourier coefficients for pure Lorentzian lines, for pure Doppler lines and for Voigt lines with at most moderate Doppler dependence. A strong-line limit sum rule on the Fourier coefficients is enforced to define an additional Fourier coefficient and to optimize convergence of the truncated expansion. The moderate Doppler dependence scenario is applicable to and has been implemented in the MODTRAN5 atmospheric band model radiative transfer software. Finite-bin transmittances computed with the truncated expansions reduce transmittance residuals compared to the former Rodgers-Williams equivalent width based approach by ∼2 orders of magnitude.

Interferometric investigation of emission lines from the solar corona

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, P.M.; Henderson, G.

1973-11-01

The profiles of the Fe XN, lambda 5303, and Fe X, lambda 6374, emission lines of the solar corona were observed at different posttions using a photoelectric scanning Fabry -- Perot interferometer. These profiles were obtained during the eclipse of 7th March 1970, in Mexico and at the Pic-du-Midi coronagraph in October, 1970. The half-widths of these profiles were determined for both the coronal lines and temperatures were derived from these widths. No systematic temperature variation was discovered, however there was some suggestion of the existence of a fluctuation with time in the width of the emission lines. (auth)

Nova V2362 Cygni (Nova Cygni 2006): Spitzer, Swift, and Ground-Based Spectral Evolution

NASA Technical Reports Server (NTRS)

Lynch, David K.; Venturini, Catherine C.; Mazuk, S.; Woodward, Charles; Gehrz, Robert; Rayner, John; Helton, L.A.; Ness, Jan-Uwe; Starrfield, Sumner; Rudy, Richard J.;

Semiclassical perturbation Stark widths of singly charged argon spectral lines

NASA Astrophysics Data System (ADS)

Hamdi, Rafik; Ben Nessib, Nabil; Sahal-Bréchot, Sylvie; Dimitrijević, Milan S.

2018-03-01

Using a semiclassical perturbation approach with the impact approximation, Stark widths for singly charged argon (Ar II) spectral lines have been calculated. Energy levels and oscillator strengths needed for this calculation have been determined using the Hartree-Fock method with relativistic corrections. Our Stark widths are compared with experimental results for 178 spectral lines. Our results may be of interest not only for laboratory plasma, lasers and technological plasmas but also for white dwarfs and A- and B-type stars.

Correcting C IV-based virial black hole masses

NASA Astrophysics Data System (ADS)

Coatman, Liam; Hewett, Paul C.; Banerji, Manda; Richards, Gordon T.; Hennawi, Joseph F.; Prochaska, J. Xavier

2017-02-01

The C IVλλ1498,1501 broad emission line is visible in optical spectra to redshifts exceeding z ˜ 5. C IV has long been known to exhibit significant displacements to the blue and these `blueshifts' almost certainly signal the presence of strong outflows. As a consequence, single-epoch virial black hole (BH) mass estimates derived from C IV velocity widths are known to be systematically biased compared to masses from the hydrogen Balmer lines. Using a large sample of 230 high-luminosity (LBol = 1045.5-1048 erg s-1), redshift 1.5 < z < 4.0 quasars with both C IV and Balmer line spectra, we have quantified the bias in C IV BH masses as a function of the C IV blueshift. C IV BH masses are shown to be a factor of 5 larger than the corresponding Balmer-line masses at C IV blueshifts of 3000 km s-1and are overestimated by almost an order of magnitude at the most extreme blueshifts, ≳5000 km s-1. Using the monotonically increasing relationship between the C IV blueshift and the mass ratio BH(C IV)/BH(Hα), we derive an empirical correction to all C IV BH masses. The scatter between the corrected C IV masses and the Balmer masses is 0.24 dex at low C IV blueshifts (˜0 km s-1) and just 0.10 dex at high blueshifts (˜3000 km s-1), compared to 0.40 dex before the correction. The correction depends only on the C IV line properties - i.e. full width at half-maximum and blueshift - and can therefore be applied to all quasars where C IV emission line properties have been measured, enabling the derivation of unbiased virial BH-mass estimates for the majority of high-luminosity, high-redshift, spectroscopically confirmed quasars in the literature.

Liners and Low Luminosity AGN in the ROSAT Database

NASA Technical Reports Server (NTRS)

Elvis, Martin; West, Donald K. (Technical Monitor)

2003-01-01

This program has led to a series of papers being written and published in the Astrophysical Journal. Together these papers try to explain major parts of the LINER and low luminosity AGN puzzle. One paper ('Accretion Disk Instabilities, Cold Dark Matter Models, and Their Role in Quasar Evolution', Hatziminaoglou E., Siemiginowska A., & Elvis M., 2001, ApJ, 547, 90) describes an analytical model for the evolution of the quasar luminosity function. By combining the Press-Schechter formalism for the masses of initial structures with the luminosity distribution for a population of single mass black holes given by an unstable accretion disk an almost complete end-to-end physics-based model of quasar evolution is produced. In this model black holes spend 75% of their time in a low accretion state (at L(Edd)). This low state population of black holes is likely to be observed as the LINER and low luminosity AGNs in the local universe. Another paper ('Broad Emission Line Regions in AGN: the Link with the Accretion Power', Nicastro F., 2000, ApJ Letters, 530, L65) gives a physical basis for why low state black holes appear as LINERS. By linking the Lightman-Eardley instability in an accretion disk to the ori.gin of a wind that contains the broad emission line cloud material this model explains the large widths seen in these lines as being the Keplerian velocity of the disk at the instability radius. For LINERS the key is that below an accretion rate of 10(exp -3)M(sub Edd)the Lightman-Eardley instability falls within the innermost stable orbit of the disk, and so leaves the entire disk stable. No wind occurs, and so no broad emission lines are seen. Most LINERS are likely to be black holes in this low state. Tests of this model are being considered.

Near-infrared spectroscopy of a nitrogen-loud quasar SDSS J1707+6443

NASA Astrophysics Data System (ADS)

Araki, N.; Nagao, T.; Matsuoka, K.; Marconi, A.; Maiolino, R.; Ikeda, H.; Hashimoto, T.; Taniguchi, Y.; Murayama, T.

2012-07-01

We present near-infrared spectroscopy of the z ≃ 3.2 quasar SDSS J1707+6443, obtained with MOIRCS on the Subaru Telescope. This quasar is classified as a "nitrogen-loud" quasar because of the fairly strong N iii] and N iv] semi-forbidden emission lines from the broad-line region (BLR) observed in its rest-frame UV spectrum. However, our rest-frame optical spectrum from MOIRCS shows strong [O iii] emission from the narrow-line region (NLR), suggesting that, at variance with the BLR, NLR gas is not metal-rich. To reconcile these contradictory results, there may be two alternative possibilities: (1) the strong nitrogen lines from the BLR are simply caused by a very high relative abundance of nitrogen and not by a very high BLR metallicity, or (2) the BLR metallicity is not representative of the metallicity of the host galaxy, which is better traced by the NLR. In either case, the strong broad nitrogen lines in the UV spectrum are ot indication of a chemically enriched host galaxy. We estimated the black hole mass and Eddington ratio of this quasar from the velocity width of both C iv and Hβ, which results in log (MBH/M⊙) = 9.50 and log (Lbol/LEdd) = -0.34. The relatively high Eddington ratio is consistent with our earlier result that strong nitrogen emission from BLRs is associated with high Eddington ratios. Finally, we detected significant [Ne iii] emission from the NLR, implying a quite high gas density of ne ~ 106 cm-3 and suggesting a strong coupling between quasar activity and dense interstellar clouds in the host galaxy.

HST FUV monitoring of TW Hya

NASA Astrophysics Data System (ADS)

Guenther, Hans; Brickhouse, N. S.; Dupree, A. K.; Luna, G.; Schneider, P. C.; Wolk, S. J.

2014-01-01

Classical T Tauri stars (CTTS) show strong, broad and asymmetric FUV emission lines. Neither the width, nor the line profile is understood. Likely, different mechanisms influence the line profile; the best candidates are accretion, winds and stellar activity. We monitored the C IV 1548/1550 Å doublet in the nearby, bright CTTS TW Hya to correlate it with i) the cool wind, as seen in COS NUV Mg II line profiles, ii) the photometric period from joint ground-based monitoring, iii) the accretion rate as determined from the UV continuum and iv) the Ha line profile from independent ground-based observations. The observations span 10 orbits distributed over a few weeks to cover the typical time scales of stellar rotation, accretion and winds. On short time scales (seconds) the variability in the data is compatible with counting statistics when we take certain instrumental effects (the detector dead-time fraction increases when the wavelength calibration lamps are switched on). This rules out any type of coherent accretion shock fluctuation as predicted in some simulations. On longer time scales (days) variability of a factor of 3 in the continuum and similarly massive changes in the line shape are seen. The ratio of the two lines of the doublet indicates that the lines are optically thick, calling into question the idea that the blue-shifted components of the C IV lines are formed in the pre-shock region.

Characterization of lunar ferromagnetic phases by the effective linewidth method

NASA Technical Reports Server (NTRS)

Patton, C. E.; Schmidt, H.

1978-01-01

The effective line-width technique, first developed to study the physics of microwave relaxation in ferrites, has been successfully applied to lunar matter. Effective line-width measurements have been made on two selected samples containing disperse spherical metallic iron particles below 40 microns in diam. The data were obtained for fields from 7 to 12 kOe and a temperature range 125 - 300 K. The effective line width was field-independent and temperature-independent at 650 - 750 Oe. The high-field tails of the ferromagnetic resonance absorption were highly Lorentzian. From the relatively large and temperature-independent high-field effective line widths, it appears that (1) the metallic iron phases in lunar soil are rather impure; (2) the impurities are passive, in that there is no evidence for a temperature peak process; and (3) these samples contain no appreciable magnetite.

Controls on valley width in mountainous landscapes: the role of landsliding and implications for salmonid habitat

Treesearch

C. May; J. Roering; L.S. Eaton; K.M. Burnett

2013-01-01

A fundamental yet unresolved question in fluvial geomorphology is what controls the width of valleys in mountainous terrain. Establishing a predictive relation for valley floor width is critical for realizing links between aquatic ecology and geomorphology because the most productive riverine habitats often occur in low-gradient streams with broad floodplains. Working...

Comparison of Trajectory Models in Calculations of N2-broadened Half-widths and N2-induced Line Shifts for the Rotational Band of H2O-16 and Comparison with Measurements

NASA Technical Reports Server (NTRS)

Lamouroux, J.; Gamache, R. R.; Laraia, A. L.; Ma, Q.; Tipping, R. H.

2012-01-01

In this work, Complex Robert-Bonamy calculations of half-widths and line shifts were done for N2-broadening of water for 1639 transitions in the rotational band using two models for the trajectories. The first is a model correct to second order in time, the Robert-Bonamy parabolic approximation. The second is the solution of Hamilton's equations. Both models use the isotropic part of the atom-atom potential to determine the trajectories. The present calculations used an intermolecular potential expanded to 20th order to assure the convergence of the half-widths and line shifts. The aim of the study is to assess if the difference in the half-widths and line shifts determined from the two trajectory models is greater than the accuracy requirements of the spectroscopic and remote sensing communities. The results of the calculations are compared with measurements of the half-widths and line shifts. It is shown that the effects of the trajectory model greatly exceed the needs of current remote sensing measurements and that line shape parameters calculated using trajectories determined by solving Hamilton's equations agree better with measurement.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Siyao; Lazarian, A.; Yan, Huirong, E-mail: hryan@pku.edu.cn

We address the problem of the different line widths of coexistent neutrals and ions observed in molecular clouds and explore whether this difference can arise from the effects of magnetohydrodynamic (MHD) turbulence acting on partially ionized gas. Among the three fundamental modes of MHD turbulence, we find that fast and slow modes do not contribute to line width differences. We focus on the Alfvénic component, and consider the damping of Alfvén modes by taking into account both neutral-ion collisions and neutral viscosity. We confirm that the line width difference can be explained by the differential damping of the Alfvénic turbulencemore » in ions and the hydrodynamic turbulence in neutrals, and find it strongly depends on the properties of MHD turbulence. We consider various regimes of turbulence corresponding to different media magnetizations and turbulent drivings. In the case of super-Alfvénic turbulence, when the damping scale of Alfvénic turbulence is below the Alfvénic scale l{sub A}, the line width difference does not depend on magnetic field strength. In other turbulence regimes, however, the dependence is present and evaluation of magnetic field from the observed line width difference is possible.« less

Location of Osteochondritis Dissecans Lesions of the Capitellum.

PubMed

Johnson, Christine C; Roberts, Susanne; Mintz, Douglas; Fabricant, Peter D; Hotchkiss, Robert N; Daluiski, Aaron

2018-04-17

The location of capitellar osteochondritis dissecans (OCD) lesions in the sagittal plane guides the surgical approach, and lesion location in the coronal plane influences surgical management. Although most lesions have been reported to occur between 4 o'clock and 4:30 (120° to 135° anterior to the humerus), some lesions are located elsewhere in the capitellum. The primary aim was to define the region of the capitellum affected by OCD lesions using a novel clock-face localization system. We reviewed 104 magnetic resonance imaging examinations diagnosing a nontraumatic capitellar OCD lesion. In the sagittal plane, lesion margins were recorded as degrees on the capitellum and converted into a clock-face format in which 0° corresponds to 12:00 with the forearm facing to the right. The 0° axis (12-o'clock axis) was defined as a line parallel to the anterior humeral line that intersects the capitellum center. The following coronal measurements were recorded: lesion width, capitellar width, and distance between the lateral capitellum and lateral lesion. Two independent observers took measurements. In the sagittal plane, average lesion location was 92° to 150° (3:04-5:00, clock face) and ranged from 52.1° to 249.5° (1:44-8:19, clock face). Average lesion dimensions were 10.7 mm (mediolateral width) and 5.2 mm (anteroposterior depth). Interrater reliability was high (intraclass correlation coefficient = 0.98). Using a magnetic resonance imaging-based clock-face localization system, we found that capitellar OCD lesions affect a broad region of the capitellum in the sagittal plane. The clock-face localization system allows for precise description of capitellar OCD lesion location, which may facilitate intraoperative decision and longitudinal monitoring. Copyright © 2018 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

CA II K-line metallicity indicator for field RR Lyrae stars

NASA Astrophysics Data System (ADS)

Clementini, Gisella; Tosi, Monica; Merighi, Roberto

In order to check and, possibly, improve the Preston's Delta S calibration scale, CCD spectra have been obtained for 25 field RR Lyrae variables. Eleven of the program stars have values of (Fe/H) derived by Butler and Deming (1979) from the Fe II lines' strength. For them we find that the equivalent width of the Ca II K line is extremely well correlated to the (Fe/H) values, the best fit relation being: (Fe/H) = 0.43W(K) - 2.75 where W(K) is the equivalent width of the K line. We conclude that the use of the K line equivalent width is at present the best method to derive the (Fe/H) abundance of the RR Lyrae stars.

Supplement Analysis for the Transmission System Vegetation Management Program FEIS (DOE/EIS-0285/SA-192- Ashe-Hanford/Scooteney-Tap

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hutchinson, Ken

2004-01-26

Vegetation Management for the Ashe-Hanford (tower 13/1 to 15/2) and Scooteney Tap (tower 2/1+1200 to 4/1+50) line corridor. The Ashe-Hanford line is a 500 kV single circuit transmission line having an easement width of 350 feet. The Scooteney Tap line is a 230 kV single circuit line having an easement width of 262.5 feet on the Department of Energy’s Hanford Nuclear Reservation (Reservation) and an easement width of 100 feet on private lands. The proposed work will be accomplished in the indicated sections of the transmission lines as referenced on the attached checklist. The work will include the performance ofmore » tower pad maintenance and access road maintenance in the referenced areas. Maintenance will include the control of all brush species within 30 feet of transmission structures and controlling all vegetation, except grass along the access roads to provide a 14-foot width for travel. Noxious weed management will also occur on the rights-of- way where needed.« less

An effective selection method for low-mass active black holes and first spectroscopic identification

NASA Astrophysics Data System (ADS)

Morokuma, Tomoki; Tominaga, Nozomu; Tanaka, Masaomi; Yasuda, Naoki; Furusawa, Hisanori; Taniguchi, Yuki; Kato, Takahiro; Jiang, Ji-an; Nagao, Tohru; Kuncarayakti, Hanindyo; Morokuma-Matsui, Kana; Ikeda, Hiroyuki; Blinnikov, Sergei; Nomoto, Ken'ichi; Kokubo, Mitsuru; Doi, Mamoru

2016-06-01

We present a new method for effectively selecting objects which may be low-mass active black holes (BHs) at galaxy centers using high-cadence optical imaging data, and our first spectroscopic identification of an active 2.7 × 106 M⊙ BH at z = 0.164. This active BH was originally selected due to its rapid optical variability, from a few hours to a day, based on Subaru Hyper Suprime-Cam g-band imaging data taken with a 1 hr cadence. Broad and narrow Hα lines and many other emission ones are detected in our optical spectra taken with Subaru FOCAS, and the BH mass is measured via the broad Hα emission line width (1880 km s-1) and luminosity (4.2 × 1040 erg s-1) after careful correction to the atmospheric absorption around 7580-7720 Å. We measure the Eddington ratio and find it to be as low as 0.05, considerably smaller than those in a previous SDSS sample with similar BH mass and redshift, which indicates one of the special potentials of our Subaru survey. The g - r color and morphology of the extended component indicate that the host galaxy is a star-forming galaxy. We also show the effectiveness of our variability selection for low-mass active BHs.

On-line Raman spectroscopy of calcite and malachite during irradiation with swift heavy ions

NASA Astrophysics Data System (ADS)

Dedera, Sebastian; Burchard, Michael; Glasmacher, Ulrich A.; Schöppner, Nicole; Trautmann, Christina; Severin, Daniel; Romanenko, Anton; Hubert, Christian

2015-12-01

A new on-line Raman System, which was installed at the M3-beamline at the UNILAC, GSI Helmholtzzentrum für Schwerionenforschung Darmstadt was used for first "in situ" spectroscopic measurements. Calcite and malachite samples were irradiated in steps between 1 × 109 and 1 × 1012 ions/cm2 with Au ions (calcite) and Xe ions (malachite) at an energy of 4.8 MeV/u. After irradiation, calcite revealed a new Raman band at 437 cm-1 and change of the full width at half maximum for the 1087 cm-1 Raman band. The Raman bands of malachite change significantly with increasing fluence. Up to a fluence of 7 × 1010 ions/cm2, all existing bands decrease in intensity. Between 8 × 1010 and 1 × 1011 ions/cm2 a broad Cu2O band between 110 and 220 cm-1 occurs, which superimposes the pre-existing Raman bands. Additionally, a new broad band between 1000 and 1750 cm-1 is formed, which is interpreted as a carbon coating. In contrast to the Cu2O band, the carbon band vanished when further irradiating the sample. The installations as well as first in situ measurements at room temperature are presented.

An infrared view of AGN feedback in a type-2 quasar: the case of the Teacup galaxy

NASA Astrophysics Data System (ADS)

Ramos Almeida, C.; Piqueras López, J.; Villar-Martín, M.; Bessiere, P. S.

2017-09-01

We present near-infrared integral field spectroscopy data obtained with Very Large Telescope/Spectrograph for INtegral Field Observations in the Near Infrared (SINFONI) of 'the Teacup galaxy'. The nuclear K-band (1.95-2.45 μm) spectrum of this radio-quiet type-2 quasar reveals a blueshifted broad component of FWHM ˜ 1600-1800 km s-1 in the hydrogen recombination lines (Pa α, Br δ and Br γ) and also in the coronal line [Si VI] λ1.963 μm. Thus, the data confirm the presence of the nuclear ionized outflow previously detected in the optical range and reveal its coronal counterpart. Both the ionized and coronal nuclear outflows are resolved, with seeing-deconvolved full widths at half-maximum of 1.1 ± 0.1 and 0.9 ± 0.1 kpc along position angle (PA) ˜ 72°-74°. This orientation is almost coincident with the radio axis (PA = 77°), suggesting that the radio jet could have triggered the nuclear outflow. In the case of the H2 lines, we do not require a broad component to reproduce the profiles, but the narrow lines are blueshifted by ˜50 km s-1 on average from the galaxy systemic velocity. This could be an indication of the presence of a nuclear molecular outflow, although the bulk of the H2 emission in the inner ˜2 arcsec (˜3 kpc) of the galaxy follows a rotation pattern. We find evidence for kinematically disrupted gas (FWHM > 250 km s-1) at up to 5.6 kpc from the AGN, which can be naturally explained by the action of the outflow. The narrow component of [Si VI] is redshifted with respect to the systemic velocity, unlike any other emission line in the K-band spectrum. This indicates that the region where the coronal lines are produced is not cospatial with the narrow-line region.

Line Profile of H Lyman-Beta Emission from Dissociative Excitation of H2

NASA Technical Reports Server (NTRS)

Ajello, Joseph M.; Ahmed, Syed M.; Liu, Xian-Ming

1996-01-01

A high-resolution ultraviolet spectrometer was employed for a measurement of the H Lyman-Beta(H L(sub Beta)) emission Doppler line profile at 1025.7 A from dissociative excitation of H2 by electron impact. Analysis of the deconvolved line profile reveals the existence of a narrow central peak, less than 30 mA full width at half maximum (FWHM), and a broad pedestal base about 260 mA FWHM. Analysis of the red wing of the line profile is complicated by a group of Wemer and Lyman rotational lines 160-220 mA from the line center. Analysis of the blue wing of the line profile gives the kinetic-energy distribution. There are two main kinetic-energy components to the H(3p) distribution: (1) a slow distribution with a peak value near 0 eV from singly excited states, and (2) a fast distribution with a peak contribution near 7 eV from doubly excited states. Using two different techniques, the absolute cross section of H L(sub Beta)p is found to be 3.2+/-.8 x 10(exp -19)sq cm at 100-eV electron impact energy. The experimental cross-section and line-profile results can be compared to previous studies of H(alpha) (6563.7 A) for principal quantum number n=3 and L(sub alpha)(1215.7 A) for n=2.

Anomalous broadening and shift of emission lines in a femtosecond laser plasma filament in air

NASA Astrophysics Data System (ADS)

Ilyin, A. A.; Golik, S. S.; Shmirko, K. A.; Mayor, A. Yu.; Proschenko, D. Yu.

2017-12-01

The temporal evolution of the width and shift of N I 746.8 and O I 777.4 nm lines is investigated in a filament plasma produced by a tightly focused femtosecond laser pulse (0.9 mJ, 48 fs). The nitrogen line shift and width are determined by the joint action of electron impact shift and the far-off resonance AC Stark effect. The intensive (I = 1.2·1010 W/cm2) electric field of ASE (amplified spontaneous emission) and post-pulses result in a possible LS coupling break for the O I 3p 5P level and the generation of Rabi sidebands. The blueshifted main femtosecond pulse and Rabi sideband cause the stimulated emission of the N2 1+ system. The maximal widths of emission lines are approximately 6.7 times larger than the calculated Stark widths.

An Explanation of Remarkable Emission-line Profiles in Post-flare Coronal Rain

NASA Astrophysics Data System (ADS)

Lacatus, Daniela A.; Judge, Philip G.; Donea, Alina

2017-06-01

We study broad redshifted emission in chromospheric and transition region lines that appears to correspond to a form of post-flare coronal rain. Profiles of Mg II, C II, and Si IV lines were obtained using IRIS before, during, and after the X2.1 flare of 2015 March 11 (SOL2015-03-11T16:22). We analyze the profiles of the five transitions of Mg II (the 3p-3s h and k transitions, and three lines belonging to the 3d-3p transitions). We use analytical methods to understand the unusual profiles, together with higher-resolution observational data of similar phenomena observed by Jing et al. The peculiar line ratios indicate anisotropic emission from the strands that have cross-strand line center optical depths (k line) of between 1 and 10. The lines are broadened by unresolved Alfvénic motions whose energy exceeds the radiation losses in the Mg II lines by an order of magnitude. The decay of the line widths is accompanied by a decay in the brightness, suggesting a causal connection. If the plasma is ≲99% ionized, ion-neutral collisions can account for the dissipation; otherwise, a dynamical process seems necessary. Our work implies that the motions are initiated during the impulsive phase, to be dissipated as radiation over a period of an hour, predominantly by strong chromospheric lines. The coronal “rain” we observe is far more turbulent than most earlier reports have indicated, with implications for plasma heating mechanisms.

Extremely red quasars from SDSS, BOSS and WISE: classification of optical spectra

NASA Astrophysics Data System (ADS)

Ross, Nicholas P.; Hamann, Fred; Zakamska, Nadia L.; Richards, Gordon T.; Villforth, Carolin; Strauss, Michael A.; Greene, Jenny E.; Alexandroff, Rachael; Brandt, W. Niel; Liu, Guilin; Myers, Adam D.; Pâris, Isabelle; Schneider, Donald P.

2015-11-01

Quasars with extremely red infrared-to-optical colours are an interesting population that can test ideas about quasar evolution as well as orientation, obscuration and geometric effects in the so-called AGN unified model. To identify such a population, we match the quasar catalogues of the Sloan Digital Sky Survey (SDSS), the Baryon Oscillation Spectroscopic Survey (BOSS) to the Wide-Field Infrared Survey Explorer (WISE) to identify quasars with extremely high infrared-to-optical ratios. We identify 65 objects with rAB - W4Vega > 14 mag (i.e. Fν(22 μm)/Fν(r) ≳ 1000). This sample spans a redshift range of 0.28 < z < 4.36 and has a bimodal distribution, with peaks at z ˜ 0.8 and z ˜ 2.5. It includes three z > 2.6 objects that are detected in the W4 band but not W1 or W2 (i.e. `W1W2 dropouts'). The SDSS/BOSS spectra show that the majority of the objects are reddened type 1 quasars, type 2 quasars (both at low and high redshift) or objects with deep low-ionization broad absorption lines (BALs) that suppress the observed r-band flux. In addition, we identify a class of type 1 permitted broad emission-line objects at z ≃ 2-3 which are characterized by emission line rest-frame equivalent widths (REWs) of ≳150 Å, much larger than those of typical quasars. In particular, 55 per cent (45 per cent) of the non-BAL type 1s with measurable C IV in our sample have REW(C IV) > 100 (150) Å, compared to only 5.8 per cent (1.3 per cent) for non-BAL quasars in BOSS. These objects often also have unusual line ratios, such as very high N V/Ly α ratios. These large REWs might be caused by suppressed continuum emission analogous to type 2 quasars; however, there is no obvious mechanism in standard unified models to suppress the continuum without also obscuring the broad emission lines.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bentz, Misty C.; Walsh, Jonelle L.; Barth, Aaron J.

2009-11-01

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

First identification of pure rotation lines of NH in the infrared solar spectrum

NASA Technical Reports Server (NTRS)

Geller, M.; Farmer, C. B.; Norton, R. H.; Sauval, A. J.; Grevesse, N.

1991-01-01

Pure rotation lines of NH of the v = 0 level and v = 1 level are detected in high-resolution solar spectra obtained from the Atmospheric Trace Molecule Spectroscopy (ATMOS) experimental observations. It is pointed out that the identification of the lines is favored by the typical appearance of the triplet lines of nearly equal intensities. The observed equivalent widths of these triplet lines are compared with predicted intensities, and it is observed that these widths are systematically larger than the predicted values. It is noted that because these very faint lines are observed in a region where the signal is very low, a systematic error in the measurements of the equivalent widths cannot be ruled out; therefore, the disagreement between the observed and predicted intensities is not considered to be real.

Split-cross-bridge resistor for testing for proper fabrication of integrated circuits

NASA Technical Reports Server (NTRS)

Buehler, M. G. (Inventor)

1985-01-01

An electrical testing structure and method is described whereby a test structure is fabricated on a large scale integrated circuit wafer along with the circuit components and has a van der Pauw cross resistor in conjunction with a bridge resistor and a split bridge resistor, the latter having two channels each a line width wide, corresponding to the line width of the wafer circuit components, and with the two channels separated by a space equal to the line spacing of the wafer circuit components. The testing structure has associated voltage and current contact pads arranged in a two by four array for conveniently passing currents through the test structure and measuring voltages at appropriate points to calculate the sheet resistance, line width, line spacing, and line pitch of the circuit components on the wafer electrically.

A survey of ultraviolet interstellar absorption lines

NASA Technical Reports Server (NTRS)

Bohlin, R. C.; Jenkins, E. B.; Spitzer, L., Jr.; York, D. G.; Hill, J. K.; Savage, B. D.; Snow, T. P., Jr.

1983-01-01

A telescope-spectrometer on the Copernicus spacecraft made possible the measurement of many ultraviolet absorption lines produced by the interstellar gas. The present survey provides data on ultraviolet absorption lines in the spectra of 88 early-type stars. The stars observed are divided into four classes, including reddened stars, unreddened bright stars, moderately reddened bright stars, and unreddened and moderately reddened faint stars. Data are presented for equivalent width, W, radial velocity V, and rms line width, D, taking into account some 10 to 20 lines of N I, O I, Si II, P II, S II, Cl I, Cl II, Mn II, Fe II, Ni II, Cu II, and H2. The data are based on multiple scans for each line. Attention is given to details of observations, the data reduction procedure, and the computation of equivalent width, mean velocity, and velocity dispersion.

Stark broadening of He I lines

NASA Astrophysics Data System (ADS)

Dimitrijevic, M. S.; Sahal-Brechot, S.

1990-03-01

Results are presented from calculations of the electron-, proton-, and ionized helium-impact line widths and shifts for 77 neutral helium multiplets in the UV, visible, and IR regions of the spectrum. The calculations are performed using a semiclassical perturbation formalism (Sahal-Brechot, 1969). Tables are given for the line widths and shift for He I resonance lines at a perturber density of 10 to the 13th/cu cm.

970-nm ridge waveguide diode laser bars for high power DWBC systems

NASA Astrophysics Data System (ADS)

Wilkens, Martin; Erbert, Götz; Wenzel, Hans; Knigge, Andrea; Crump, Paul; Maaßdorf, Andre; Fricke, Jörg; Ressel, Peter; Strohmaier, Stephan; Schmidt, Berthold; Tränkle, Günther

2018-02-01

de lasers are key components in material processing laser systems. While mostly used as pump sources for solid state or fiber lasers, direct diode laser systems using dense wavelength multiplexing have come on the market in recent years. These systems are realized with broad area lasers typically, resulting in beam quality inferior to disk or fiber lasers. We will present recent results of highly efficient ridge waveguide (RW) lasers, developed for dense-wavelength-beamcombining (DWBC) laser systems expecting beam qualities comparable to solid state laser systems and higher power conversion efficiencies (PCE). The newly developed RW lasers are based on vertical structures with an extreme double asymmetric large optical cavity. Besides a low vertical divergence these structures are suitable for RW-lasers with (10 μm) broad ridges, emitting in a single mode with a good beam quality. The large stripe width enables a lateral divergence below 10° (95 % power content) and a high PCE by a comparably low series resistance. We present results of single emitters and small test arrays under different external feedback conditions. Single emitters can be tuned from 950 nm to 975 nm and reach 1 W optical power with more than 55 % PCE and a beam quality of M2 < 2 over the full wavelength range. The spectral width is below 30 pm FWHM. 5 emitter arrays were stabilized using the same setup. Up to now we reached 3 W optical power, limited by power supply, with 5 narrow spectral lines.

Precision Fe K-Alpha and Fe K-Beta Line Spectroscopy of the Seyfert 1.9 Galaxy NGC 2992 with Suzaku

NASA Technical Reports Server (NTRS)

Yaqoob, Tahir; Murphy, Kendrah D.; Griffiths, Richard E.; Haba, Yoshito; Inoue, Hajime; Itoh, Takeshi; Kelley, Richard; Kokubun, Motohide; Markowitz, Alex; Mushotzky, Richard;

Anomalous H-beta Variability in the 2014 NGC 5548 AGN-STORM Monitoring Campaign

NASA Astrophysics Data System (ADS)

Pei, Liuyi; AGN STORM Collaboration

2016-06-01

Reverberation mapping programs generally find that the continuum and H-beta flux variations in AGNs are well correlated. In the 2014 AGN STORM monitoring program for NGC 5548, we observed a distinct decorrelation of the emission-line light curves from the AGN continuum light curve during the second half of the six-month campaign. This effect was first detected for the C IV, Ly a, HeII 1640 and SiIV/OIV] 1400 lines in Hubble Space Telescope data, then observed for the H-beta line in ground-based data taken during the same monitoring period. We present measurements of the H-beta lags, equivalent width variations, and line responsivity changes during our campaign. We show that the AGN demonstrated unusual behavior in that the broad H-beta responsivity to flux variations decreased significantly during the second half of the campaign. The discovery of this decorrelation phenomenon was made possible by the high cadence and long duration of our monitoring campaign. More multi-wavelength observing campaigns with high sampling cadence, high signal-to-noise ratio, and long temporal baseline are needed for other AGNs in order to determine the prevalence of this phenomenon and to understand its physical origin.

Electron-electron correlations in Raman spectra of VO2

NASA Astrophysics Data System (ADS)

Goncharuk, I. N.; Ilinskiy, A. V.; Kvashenkina, O. E.; Shadrin, E. B.

2013-01-01

It has been shown that, in single crystals and films of a strongly correlated material, namely, vanadium dioxide, upon a thermally stimulated phase transition from the low-temperature monoclinic phase to the high-temperature tetragonal phase, the narrow-line Raman spectrum of the insulating (monoclinic) phase transforms into the broad-band Raman spectrum, which contains two peaks at 500 and 5000 cm-1 with widths of 400 and 3500 cm-1, respectively. It has been found that, as the temperature of the monoclinic phase approaches the structural phase transition temperature (340 K), the line profile of soft-mode phonons at a frequency of 149 cm-1 with A g symmetry and the line profile of phonons at a frequency of 201 cm-1 with A g symmetry acquire an asymmetric shape with a Fano antiresonance that is characteristic of the interaction of a single phonon vibration with a continuum of strongly correlated electrons. It has been demonstrated that the thermal transformation of peaks in the Raman spectra of the VO2 metallic phase is in quantitative agreement with the theory of Raman scattering in strongly correlated materials.

CO{sub 2} isolated line shapes by classical molecular dynamics simulations: Influence of the intermolecular potential and comparison with new measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larcher, G.; Tran, H., E-mail: ha.tran@lisa.u-pec.fr; Schwell, M.

2014-02-28

Room temperature absorption spectra of various transitions of pure CO{sub 2} have been measured in a broad pressure range using a tunable diode-laser and a cavity ring-down spectrometer, respectively, in the 1.6 μm and 0.8 μm regions. Their spectral shapes have been calculated by requantized classical molecular dynamics simulations. From the time-dependent auto-correlation function of the molecular dipole, including Doppler and collisional effects, spectral shapes are directly computed without the use of any adjusted parameter. Analysis of the spectra calculated using three different anisotropic intermolecular potentials shows that the shapes of pure CO{sub 2} lines, in terms of both themore » Lorentz widths and non-Voigt effects, slightly depend on the used potential. Comparisons between these ab initio calculations and the measured spectra show satisfactory agreement for all considered transitions (from J = 6 to J = 46). They also show that non-Voigt effects on the shape of CO{sub 2} transitions are almost independent of the rotational quantum number of the considered lines.« less

Emission Line Properties of Seyfert Galaxies in the 12 μm Sample

NASA Astrophysics Data System (ADS)

Malkan, Matthew A.; Jensen, Lisbeth D.; Rodriguez, David R.; Spinoglio, Luigi; Rush, Brian

2017-09-01

We present optical and ultraviolet spectroscopic measurements of the emission lines of 81 Seyfert 1 and 104 Seyfert 2 galaxies that comprise nearly all of the IRAS 12 μm AGN sample. We have analyzed the emission-line luminosity functions, reddening, and other diagnostics. For example, the narrow-line regions (NLR) of Seyfert 1 and 2 galaxies do not significantly differ from each other in most of these diagnostics. Combining the Hα/Hβ ratio with a new reddening indicator—the [S II]6720/[O II]3727 ratio—we find the average E(B-V) is 0.49 ± 0.35 for type 1 and 0.52 ± 0.26 for type 2 Seyferts. The NLR of Sy 1s has an ionization level insignificantly higher than that of Sy 2s. For the broad-line region (BLR), we find that the C IV equivalent width correlates more strongly with [O III]/Hβ than with UV luminosity. Our bright sample of local active galaxies includes 22 Seyfert nuclei with extremely weak broad wings in Hα, known as Seyfert 1.9s and 1.8s, depending on whether or not broad Hβ wings are detected. Aside from these weak broad lines, our low-luminosity Seyferts are more similar to the Sy 2s than to Sy 1s. In a BPT diagram, we find that Sy 1.8s and 1.9s overlap the region occupied by Sy 2s. We compare our results on optical emission lines with those obtained by previous investigators, using AGN subsamples from the Sloan Digital Sky Survey. The luminosity functions of forbidden emission lines [O II]λ3727 Å, [O III]λ5007 Å, and [S II]λ6720 Å in Sy 1s and Sy 2s are indistinguishable. They all show strong downward curvature. Unlike the LFs of Seyfert galaxies measured by the Sloan Digital Sky Survey, ours are nearly flat at low luminosities. The larger number of faint Sloan “AGN” is attributable to their inclusion of weakly emitting LINERs and H II+AGN “composite” nuclei, which do not meet our spectral classification criteria for Seyferts. In an Appendix, we have investigated which emission line luminosities can provide the most reliable measures of the total non-stellar luminosity, estimated from our extensive multi-wavelength database. The hard X-ray or near-ultraviolet continuum luminosity can be crudely predicted from either the [O III]λ5007 Å luminosity or the combinations of [O III]+Hβ or [N II]+Hα lines, with a scatter of +/- 4 times for Sy 1s and +/- 10 times for Sy 2s. Although these uncertainties are large, the latter two hybrid (NLR+BLR) indicators have the advantage of predicting the same HX luminosity independent of Seyfert type.

Spectroscopic requirements for HALOE: An analysis of the HCl and HF channels

NASA Technical Reports Server (NTRS)

Rinsland, C. P.; Smith, M. A. H.; Park, J. H.; Harvey, G. A.; Russell, J. M., III; Richardson, D. J.

1982-01-01

Spectral line parameters that have absorption features within the HCl and HF channels of the Halogen Occultation Experiment (HALOE) were evaluated. Line positions and identification of stratospheric and solar absorption features in both channels are presented based on an analysis of high-resolution, balloon-borne solar occultation spectra. For the relevant HCl and HF lines and for transitions of the interfering species, the accuracy of the following spectral parameters was assessed: line positions, line strengths, lower state energies, air-broadened collisional half-widths, and temperature dependence of the air-broadened half-widths. In addition, since the HALOE instrument and calibration cells are filled with mixtures of HCl in N2 and HF in N2, the self-broadened and N2-broadened HF and HCl half-widths were also considered.

Lunar Sodium and Potassium Exosphere in May 2014

NASA Astrophysics Data System (ADS)

Oliversen, R. J.; Kuruppuaratchi, D. C. P.; Mierkiewicz, E. J.; Derr, N. J.; Rosborough, S.; Gallant, M. A.; Roesler, F. L.

2015-12-01

We apply high resolution spectroscopy to investigate the lunar exosphere by measuring sodium and potassium spectral line profiles to determine the variations in exospheric effective temperatures and velocities. Observations were made at the National Solar Observatory McMath-Pierce Telescope during May 2014. Data were collected over several nights, centered on full moon (May 14) and covering a waxing phase angle of 67° to a waning phase angle of 75°. We used a dual-etalon Fabry-Perot spectrometer with a resolving power of 184,000 (1.63 km s-1) to measure the line widths and radial velocity shifts of the sodium D2 (5889.951 Å) and potassium D1 (7698.965 Å) emission lines. The field of view was 3 arcmin (~330 km) and positioned at several locations, each centered at 1.5 arcmin (~165 km) off the East and West sunlit limbs. The deconvolved line widths indicate significant differences between the sodium and potassium temperatures. The sodium line widths were mostly symmetric as a function of phase for both the waxing and waning phases. At phase angles > 40º (outside of the magnetotail) the full width half maximum (FWHM) line widths are 1.5 - 2.0 km s-1 or ~1500 K for FWHM = 1.75 km s-1. Inside the magnetotail (phase angle < 40º) and near full moon (phase angle ~6°), the FWHM increased to ~4 km s-1. The implied line width temperature is 8000 K, although some of the observed line width may be due to a dispersion in velocities from many contribution along the extended sodium tail. Unlike sodium, the potassium line widths are wider by 50% during the waxing phase compared to the waning phase at phases > 40º. The potassium temperatures pre-magnetotail passage are ~1000 K while the temperatures post-magnetotail passage are ~2000K. At phase angles < 40º, the potassium intensities decreased dramatically; on consecutive days, when the phase angle changed from 44º to 31º to 20º, the relative intensities dropped by 1.0:0.6:0.15. The potassium intensity in the East and West equatorial regions (latitude < 10º) were similar; however, the potassium intensity was brightest off the limb near Aristarchus (latitude ~24º), which was the crater we observed nearest the KREEP region. This work was partially supported by the NASA Planetary Astronomy programs, NNX11AE38G and NNX13AL30G.

N2 pressure - broadened O3 line widths and strengths near 1129.4 cm-1

NASA Technical Reports Server (NTRS)

Copeland, G. E.; Majorana, L. N.; Harward, C. N.; Steinkamp, R. J.

1982-01-01

A Beer's Law experiment was performed with a tunable diode laser to find the N2 pressure broadening characteristics of a single 03 absorption line at 1129.426 cm for N2 pressures from 10 to 100 torr (O3 pressure = 3.16 torr). SO2 line positions were used for wavelength calibration. Line shapes were interatively fitted to a Lorentz function. Results were delta (HWHM in MHz) = 47.44 (+ or - 5.34) MHz + 1.730 (+ or - 0.088) MHz/torr *p(torr) with sigma = 0.9897. This intercept compares well with the Doppler O3 - O3 broadened (at 3.16 torr) width of 44.52 Hz. This result in a HWHM line width of 0.44 cm atm at 760 torr and 285 K. The line strengths integrated over delta nu = 0.55 cm were found to be N2 pressure dependent.

Ultraviolet observations of cool stars. IV - Intensities of Lyman-alpha and Mg II in epsilon Pegasi and epsilon Eridani, and line width-luminosity correlations

NASA Technical Reports Server (NTRS)

Mcclintock, W.; Linsky, J. L.; Henry, R. C.; Moos, H. W.

1975-01-01

A spectrometer on the Copernicus satellite has been used to confirm the existence of a line width-luminosity relation for the Ly-alpha and Mg II 2800-A chromospheric emission lines in K-type stars by observation of a K2 dwarf (epsilon Eri) and a K2 supergiant (epsilon Peg). Combined with previously reported observations of lines in three K giants (alpha Boo, alpha Tau, and beta Gem), the data are consistent with an identical dependence of line width on absolute visual magnitude for the Ca II K, Ly-alpha, and Mg II 2795-A lines. Surface fluxes of Ly-alpha, Mg II 2800-A, and O V 1218-A (upper limit) for epsilon Eri, and of Mg II 2800-A for epsilon Peg are also compared with values reported previously for the three giant stars.

A Multi-ionic Kinematic Investigation of NGC 595, a Giant Extragalactic H II Region in M33

NASA Astrophysics Data System (ADS)

Lagrois, Dominic; Joncas, Gilles

2009-08-01

Spectro-interferometric observations of the Hα, [O III], and [S II] optical emission lines are combined with radio observations of the 21 cm line in order to obtain a reliable kinematic image of NGC 595, the second largest giant extragalactic H II region in M33. The Hα and [O III] observations reveal that the nebula is exposed to two distinct kinematical regimes. While symmetric, broad velocity profiles dominate a sizeable fraction of the ionized extent, evidence for line splitting is detected in a small region near the most massive stars of the star cluster. A quantitative investigation proposes that two expanding wind-blown bubbles could be held responsible for the observed line splitting. The kinematics of the ionized material presenting one-component velocity profiles likely indicates that Champagne flows are present at the periphery of the molecular component leading to accelerated ionized material in the ambient interstellar medium. In areas not dominated by the photoionization of the molecular clouds, the H+ and S+ material shows a kinematical behavior roughly in agreement with the atomic gas. Mean nonthermal line widths show relatively large, supersonic values especially in [O III]. Models of structure functions indicate that the Hα and [O III] components could be exposed to different turbulent motions which could explain the broadening excess observed for the latter ion. On the full ionized extent of the nebula, the S+ material shows narrower line widths than the two other ions. Combined with the absence of line splitting, these peculiar characteristics indicate that the [S II] component is likely located at the periphery of the nebula and probably does not coexist with Hα and [O III]. The shape of the [S II] structure function is in agreement with a relatively low number of large-scale velocity gradients which partially explains the narrower profiles observed. The mean electron density in the nebula is estimated at 162 ± 106(1σ) cm-3, in agreement with previous studies of similar extragalactic H II regions. We provide the first bidimensional electron density map ever presented for a giant extragalactic nebula.

Stellar Contrails in Quasi-stellar Objects: The Origin of Broad Absorption Lines

NASA Astrophysics Data System (ADS)

Scoville, Nick; Norman, Colin

1995-10-01

Active galactic nuclei (AGNs) and quasars often exhibit infrared excesses at λ = 2-10 microns attributable to thermal dust emission. In this paper we propose that this hot dust is supplied by circumstellar mass loss from evolved stars in the nuclear star cluster. The physics of the mass-loss dust, specifically the evaporation temperature, is a critical parameter in determining the accretion rate of mass-loss material onto the central AGN. For standard interstellar dust grains with an evaporation temperature of 1800 K the dust is destroyed inside a radius of 1 pc from a central luminosity source of 5 × 10 Lsun. The mass-loss material inside 1 pc will therefore have a lower radiation pressure efficiency and accrete inward. Outside this critical radius, dust may survive, and the mass loss is accelerated outward owing to the high radiation pressure efficiency of the dust mixed with the gas. The outflowing material will consist of discrete trails of debris shed by the individual mass-loss stars, and we suggest that these trails produce the broad absorption lines (BALs) seen in 5%-10% of QSOs. The model accounts naturally for the maximum outflow velocities seen in the BALs (˜30,000 km s-1 and varying as L¼) since this maximum terminal velocity occurs for matter originating at the inner edge of the radiative equilibrium dust survival zone. Although the radiation pressure acts on the dust, individual grains will be highly charged (Z ˜ 103+), and the grains are therefore strongly coupled to the gas through the ambient magnetic fields. Numerical hydrodynamic calculations were done to follow the evolution of mass-loss material. As the orbiting debris is driven outward by radiation pressure, the trail forms a spiral with initially high pitch angle (˜85°). The trails are compressed into thin ribbons in the radial direction initially by the radiation pressure gradients due to absorption within the trail. After reaching > 104 km s-1 radial velocity, the compression can be maintained by ram pressure due to an ambient gas of modest density (˜102 cm-3). Each of the stellar contrails will have mean column density ˜1019-1021 cm-2, volume density ˜108-109 cm-3, and thickness 1011-1012 cm along the line of sight to the AGN corresponding to parameters deduced from observations of the BAL clouds. Assuming minimal expansion perpendicular to the line of sight at the speed of sound, the width of the trails is 1015-1016 cm, or 102-103 times the line-of-sight depth. Since the UV-emitting accretion disk probably has a radius of about 2 × 1016 cm, a single trail will only partially cover the continuum, but for the column densities quoted above the observed absorption lines (e.g., C IV) will be optically thick with τ > 10. Since the contrails are nearly radial just after leaving the star when the maximum outward acceleration occurs, a large range of velocities (˜4000 km s-1) will be seen in absorption of the QSO light from each trail, and only a few disk-crossing trails are needed to account for the full width of broad absorption line troughs.

X-Ray Reflected Spectra from Accretion Disk Models. II. Diagnostic Tools for X-Ray Observations

NASA Technical Reports Server (NTRS)

Garcia, J.; Kallman, T. R.; Mushotzky, R. F.

2011-01-01

We present a comprehensive study of the emission spectra from accreting sources. We use our new reflection code to compute the reflected spectra from an accretion disk illuminated by X-rays. This set of models covers different values of ionization parameter, solar iron abundance and photon index for the illuminating spectrum. These models also include the most complete and recent atomic data for the inner-shell of the iron and oxygen isonuclear sequences. We concentrate our analysis to the 2 - 10 keV energy region, and in particular to the iron K-shell emission lines. We show the dependency of the equivalent width (EW) of the Fe Ka with the ionization parameter. The maximum value of the EW is approx. 800 eV for models with log Epsilon approx. 1.5, and decreases monotonically as Epsilon increases. For lower values of Epsilon the Fe K(alpha) EW decreases to a minimum near log Epsilon approx. 0.8. We produce simulated CCD observations based on our reflection models. For low ionized, reflection dominated cases, the 2 -10 keV energy region shows a very broad, curving continuum that cannot be represented by a simple power-law. We show that in addition to the Fe K-shell emission, there are other prominent features such as the Si and S L(alpha) lines, a blend of Ar VIII-XI lines, and the Ca x K(alpha) line. In some cases the S xv blends with the He-like Si RRC producing a broad feature that cannot be reproduced by a simple Gaussian profile. This could be used as a signature of reflection.

Measuring the Outflow Properties of FeLoBAL Quasars

NASA Astrophysics Data System (ADS)

Dabbieri, Collin; Choi, Hyunseop; MacInnis, Francis; Leighly, Karen; Terndrup, Donald

2018-01-01

Roughly 20 percent of the quasar population shows broad absorption lines, which are indicators of an energetic wind. Within the broad absorption line class of quasars exist FeLoBAL quasars, which show strong absorption lines from the Fe II and Fe III transitions as well as other low-ionization lines. FeLoBALs are of particular interest because they are thought to possibly be a short-lived stage in a quasar's life where it expels its shroud of gas and dust. This means the winds we see from FeLoBALs are one manifestation of galactic feedback. This idea is supported by Farrah et al. (2012) who found an anti correlation between outflow strength and contribution from star formation to the total IR luminosity of the host galaxy when examining a sample of FeLoBAL quasars. We analyze the sample of 26 FeLoBALs from Farrah et al. (2012) in order to measure the properties of their outflows, including ionization, density, column density and covering fraction. The absorption and continuum profiles of these objects are modeled using SimBAL, a program which creates synthetic spectra using a grid of Cloudy models. A Monte-Carlo method is employed to determine posterior probabilities for the physical parameters of the outflow. From these probabilities we extract the distance of the outflow, the mass outflow rate and the kinetic luminosity. We demonstrate SimBAL is capable of modeling a wide range of spectral morphologies. From the 26 objects studied we observe interesting correlations between ionization parameter, distance and density. Analysis of our sample also suggests a dearth of objects with velocity widths greater than or equal to 300 km/s at distances greater than or equal to 100 parsecs.

Simultaneous X-ray and Far-Ultraviolet Spectra of AGN with ASCA and HUT

NASA Technical Reports Server (NTRS)

Kriss, Gerard A.

1997-01-01

We obtained ASCA spectra of the Seyfert 1 galaxy NGC 3516 in March 1995. Simultaneous far-UV observations were obtained with the Hopkins Ultraviolet Telescope on the Astro-2 shuttle mission. The ASCA spectrum shows a lightly absorbed power law of energy index 0.78. The low energy absorbing column is significantly less than previously seen. Prominent 0 VII and 0 VIII absorption edges are visible, but, consistent with the much lower total absorbing column, no Fe K absorption edge is detectable. A weak, narrow Fe K(alpha) emission line from cold material is present as well as a broad Fe K(alpha) line. These features are similar to those reported in other Seyfert 1 galaxies. A single warm absorber model provides only an imperfect description of the low energy absorption. In addition to a highly ionized absorber with ionization parameter U = 1.66 and a total column density of 1.4 x 10(exp 22)/sq cm, adding a lower ionization absorber with U = 0.32 and a total column of 6.9 x 10(exp 21)/sq cm significantly improves the fit. The contribution of resonant line scattering to our warm absorber models limits the Doppler parameter to less than 160 km/s at 90% confidence. Turbulence at the sound speed of the photoionized gas provides the best fit. None of the warm absorber models fit to the X-ray spectrum can match the observed equivalent widths of all the UV absorption lines. Accounting for the X-ray and UV absorption simultaneously requires an absorbing region with a broad range of ionization parameters and column densities.

Measurement of 1323 and 1487 keV resonances in 15N(α ,γ )19F with the recoil separator ERNA

NASA Astrophysics Data System (ADS)

Di Leva, A.; Imbriani, G.; Buompane, R.; Gialanella, L.; Best, A.; Cristallo, S.; De Cesare, M.; D'Onofrio, A.; Duarte, J. G.; Gasques, L. R.; Morales-Gallegos, L.; Pezzella, A.; Porzio, G.; Rapagnani, D.; Roca, V.; Romoli, M.; Schürmann, D.; Straniero, O.; Terrasi, F.; ERNA Collaboration

2017-04-01

Background: The origin of fluorine is a widely debated issue. Nevertheless, the 15N(α ,γ )19F reaction is a common feature among the various production channels so far proposed. Its reaction rate at relevant temperatures is determined by a number of narrow resonances together with the direct capture and the tails of the two broad resonances at Ec .m .=1323 and 1487 keV. Purpose: The broad resonances widths, Γγ and Γα, have to be measured with adequate precision in order to better determine their contribution to the 15N(α ,γ )19F stellar reaction rate. Methods: Measurement through the direct detection of the 19F recoil ions with the European Recoil separator for Nuclear Astrophysics (ERNA) were performed. The reaction was initiated by a 15N beam impinging onto a 4He windowless gas target. The observed yield of the resonances at Ec .m .=1323 and 1487 keV is used to determine their widths in the α and γ channels. Results: We show that a direct measurement of the cross section of the 15N(α ,γ )19F reaction can be successfully obtained with the recoil separator ERNA, and the widths Γγ and Γα of the two broad resonances have been determined. While a fair agreement is found with earlier determination of the widths of the 1487 keV resonance, a significant difference is found for the 1323 keV resonance Γα. Conclusions: The revision of the widths of the two more relevant broad resonances in the 15N(α ,γ )19F reaction presented in this work is the first step toward a more firm determination of the reaction rate. At present, the residual uncertainty at the temperatures of the 19F stellar nucleosynthesis is dominated by the uncertainties affecting the direct capture component and the 364 keV narrow resonance, both so far investigated only through indirect experiments.

Resonant electrodynamic heating of stellar coronal loops: An LRC circuit analogue

NASA Technical Reports Server (NTRS)

Ionson, J. A.

1980-01-01

The electrodynamic coupling of stellar coronal loops to underlying beta velocity fields. A rigorous analysis revealed that the physics can be represented by a simple yet equivalent LRC circuit analogue. This analogue points to the existence of global structure oscillations which resonantly excite internal field line oscillations at a spatial resonance within the coronal loop. Although the width of this spatial resonance, as well as the induced currents and coronal velocity field, explicitly depend upon viscosity and resistivity, the resonant form of the generalized electrodynamic heating function is virtually independent of irreversibilities. This is a classic feature of high quality resonators that are externally driven by a broad band source of spectral power. Applications to solar coronal loops result in remarkable agreement with observations.

Plasmonic distributed feedback lasers at telecommunications wavelengths.

PubMed

Marell, Milan J H; Smalbrugge, Barry; Geluk, Erik Jan; van Veldhoven, Peter J; Barcones, Beatrix; Koopmans, Bert; Nötzel, Richard; Smit, Meint K; Hill, Martin T

2011-08-01

We investigate electrically pumped, distributed feedback (DFB) lasers, based on gap-plasmon mode metallic waveguides. The waveguides have nano-scale widths below the diffraction limit and incorporate vertical groove Bragg gratings. These metallic Bragg gratings provide a broad bandwidth stop band (~500 nm) with grating coupling coefficients of over 5000/cm. A strong suppression of spontaneous emission occurs in these Bragg grating cavities, over the stop band frequencies. This strong suppression manifests itself in our experimental results as a near absence of spontaneous emission and significantly reduced lasing thresholds when compared to similar length Fabry-Pérot waveguide cavities. Furthermore, the reduced threshold pumping requirements permits us to show strong line narrowing and super linear light current curves for these plasmon mode devices even at room temperature.

D IR Line Shapes for Determining the Structure of a Peptide in a Bilayer

NASA Astrophysics Data System (ADS)

Woys, Ann Marie; Lin, Y. S.; Skinner, J. S.; Zanni, M. T.; Reddy, A. S.; de Pablo, J. J.

2010-06-01

Structure of the antimicrobial peptide, ovispirin, on a lipid bilayer was determined using 2D IR spectroscopy and spectra calculated from molecular dynamics simulations. Ovispirin is an 18 residue amphipathic peptide that binds parallel to the membrane in a mostly alpha helical conformation. 15 of the 18 residues were ^1^3C^1^8O isotopically labeled on the backbone to isolate the amide I vibration at each position. 2D IR spectra were collected for each labeled peptide in 3:1 POPC/POPG vesicles, and peak width along the diagonal was measured. The diagonal line width is sensitive to the vibrator's electrostatic environment, which varies through the bilayer. We observe an oscillatory line width spanning 10 to 24 cm-1 and with a period of nearly 3.6 residues. To further investigate the position of ovispirin in a bilayer, molecular dynamics simulations determined the peptide depth to be just below the lipid headgroups. The trajectory of ovispirin at this depth was used to calculate 2D IR spectra, from which the diagonal line width is measured. Both experimental and simulated line widths are similar in periodicity and suggest a kink in the peptide backbone and the tilt in the bilayer. A. Woys, Y. S. Lin, A. S. Reddy, W. Xiong, J. J. de Pablo, J. S. Skinner, and M. T. Zanni, JACS 132, 2832-2838 (2010).

PACCE: Perl Algorithm to Compute Continuum and Equivalent Widths

NASA Astrophysics Data System (ADS)

Riffel, Rogério; Borges Vale, Tibério

2011-05-01

PACCE (Perl Algorithm to Compute continuum and Equivalent Widths) computes continuum and equivalent widths. PACCE is able to determine mean continuum and continuum at line center values, which are helpful in stellar population studies, and is also able to compute the uncertainties in the equivalent widths using photon statistics.

The rebirth of Supernova 1987A : a study of the ejecta-ring collision

NASA Astrophysics Data System (ADS)

Gröningsson, Per

Supernovae are some of the most energetic phenomena in the Universe and they have throughout history fascinated people as they appeared as new stars in the sky. Supernova (SN) 1987A exploded in the nearby satellite galaxy, the Large Magellanic Cloud (LMC), at a distance of only 168,000 light years. The proximity of SN 1987A offers a unique opportunity to study the medium surrounding the supernova in great detail. Powered by the dynamical interaction of the ejecta with the inner circumstellar ring, SN 1987A is dramatically evolving at all wavelengths on time scales less than a year. This makes SN 1987A a great ``laboratory'' for studies of shock physics. Repeated observations of the ejecta-ring collision have been carried out using the UVES echelle spectrograph at VLT. This thesis covers seven epochs of high resolution spectra taken between October 1999 and November 2007. Three different emission line components are identified from the spectra. A narrow (~10 km/s) velocity component emerges from the unshocked ring. An intermediate (~250 km/s) component arises in the shocked ring, and a broad component extending to ~15,000 km/s comes from the reverse shock. Thanks to the high spectral resolution of UVES, it has been possible to separate the shocked from the unshocked ring emission. For the unshocked gas, ionization stages from neutral up to Ne V and Fe VII were found. The line fluxes of the low-ionization lines decline during the period of the observations. However, the fluxes of the [O III] and [Ne III] lines appear to increase and this is found to be consistent with the heating of the pre-shock gas by X-rays from the shock interactions. The line emission from the ejecta-ring collision increases rapidly as more gas is swept up by the shocks. This emission comes from ions with a range of ionization stages (e.g., Fe II-XIV). The low-ionization lines show an increase in their line widths which is consistent with that these lines originate from radiative shocks. The high-ionization line profiles (Fe X-XIV) initially show larger spectral widths, which indicates that at least a fraction of the emission comes from non-radiative shocks.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Modjaz, Maryam; Liu, Yuqian Q.; Bianco, Federica B.

We present the first systematic investigation of spectral properties of 17 Type Ic Supernovae (SNe Ic), 10 broad-lined SNe Ic (SNe Ic-bl) without observed gamma-ray bursts (GRBs), and 11 SNe Ic-bl with GRBs (SN-GRBs) as a function of time in order to probe their explosion conditions and progenitors. Using a number of novel methods, we analyze a total of 407 spectra, which were drawn from published spectra of individual SNe as well as from the densely time-sampled spectra of Modjaz et al (2014). In order to quantify the diversity of the SN spectra as a function of SN subtype, wemore » construct average spectra of SNe Ic, SNe Ic-bl without GRBs, and SNe Ic-bl with GRBs. We find that SN 1994I is not a typical SN Ic, contrasting the general view, while the spectra of SN 1998bw/GRB 980425 are representative of mean spectra of SNe Ic-bl. We measure the ejecta absorption and width velocities using a new method described here and find that SNe Ic-bl with GRBs, on average, have quantifiably higher absorption velocities, as well as broader line widths than SNe without observed GRBs. In addition, we search for correlations between SN-GRB spectral properties and the energies of their accompanying GRBs. Finally, we show that the absence of clear He lines in optical spectra of SNe Ic-bl, and in particular of SN-GRBs, is not due to them being too smeared-out due to the high velocities present in the ejecta. This implies that the progenitor stars of SN-GRBs are probably free of the He-layer, in addition to being H-free, which puts strong constraints on the stellar evolutionary paths needed to produce such SN-GRB progenitors at the observed low metallicities.« less

Joint SDO and IRIS Observations of a Novel, Hybrid Prominence-Coronal Rain Complex

NASA Astrophysics Data System (ADS)

Liu, Wei; Antolin, Patrick; Sun, Xudong; Gao, Lijia; Vial, Jean-Claude; Gibson, Sarah; Okamoto, Takenori; Berger, Thomas; Uitenbroek, Han; De Pontieu, Bart

2016-10-01

Solar prominences and coronal rain are intimately related phenomena, both involving cool material at chromospheric temperatures within the hot corona and both playing important roles as part of the return flow of the chromosphere-corona mass cycle. At the same time, they exhibit distinct morphologies and dynamics not yet well understood. Quiescent prominences consist of numerous long-lasting, filamentary downflow threads, while coronal rain is more transient and falls comparably faster along well-defined curved paths. We report here a novel, hybrid prominence-coronal rain complex in an arcade-fan geometry observed by SDO/AIA and IRIS, which provides new insights to the underlying physics of such contrasting behaviors. We found that the supra-arcade fan region hosts a prominence sheet consisting of meandering threads with broad line widths. As the prominence material descends to the arcade, it turns into coronal rain sliding down coronal loops with line widths 2-3 times narrower. This contrast suggests that distinct local plasma and magnetic conditions determine the fate of the cool material, a scenario supported by our magnetic field extrapolations from SDO/HMI. Specifically, the supra-arcade fan (similar to those in solar flares; e.g., McKenzie 2013) is likely situated in a current sheet, where the magnetic field is weak and the plasma-beta could be close to unity, thus favoring turbulent flows like those prominence threads. In contrast, the underlying arcade has a stronger magnetic field and most likely a low-beta environment, such that the material is guided along magnetic field lines to appear as coronal rain. We will discuss the physical implications of these observations beyond prominence and coronal rain.

Resolution Limits of Nanoimprinted Patterns by Fluorescence Microscopy

NASA Astrophysics Data System (ADS)

Kubo, Shoichi; Tomioka, Tatsuya; Nakagawa, Masaru

2013-06-01

The authors investigated optical resolution limits to identify minimum distances between convex lines of fluorescent dye-doped nanoimprinted resist patterns by fluorescence microscopy. Fluorescent ultraviolet (UV)-curable resin and thermoplastic resin films were transformed into line-and-space patterns by UV nanoimprinting and thermal nanoimprinting, respectively. Fluorescence immersion observation needed an immersion medium immiscible to the resist films, and an ionic liquid of triisobutyl methylphosphonium tosylate was appropriate for soluble thermoplastic polystyrene patterns. Observation with various numerical aperture (NA) values and two detection wavelength ranges showed that the resolution limits were smaller than the values estimated by the Sparrow criterion. The space width to identify line patterns became narrower as the line width increased. The space width of 100 nm was demonstrated to be sufficient to resolve 300-nm-wide lines in the detection wavelength range of 575-625 nm using an objective lens of NA= 1.40.

A simple formula for estimating Stark widths of neutral lines. [of stellar atmospheres

NASA Technical Reports Server (NTRS)

Freudenstein, S. A.; Cooper, J.

1978-01-01

A simple formula for the prediction of Stark widths of neutral lines similar to the semiempirical method of Griem (1968) for ion lines is presented. This formula is a simplification of the quantum-mechanical classical path impact theory and can be used for complicated atoms for which detailed calculations are not readily available, provided that the effective position of the closest interacting level is known. The expression does not require the use of a computer. The formula has been applied to a limited number of neutral lines of interest, and the width obtained is compared with the much more complete calculations of Bennett and Griem (1971). The agreement generally is well within 50% of the published value for the lines investigated. Comparisons with other formulas are also made. In addition, a simple estimate for the ion-broadening parameter is given.

Selecting maxillary anterior tooth width by measuring certain facial dimensions in the Kurdish population.

PubMed

A L-Kaisy, Neda; Garib, Balkees Taha

2016-03-01

One of the most difficult aspects of complete denture fabrication is selecting appropriately sized maxillary anterior teeth that will harmonize with the face. There are no generally accepted or naturally observed principles to guide dentists in this selection. The purpose of this study was to determine whether a relationship exists between various facial measurements and the different single or combined mesiodistal widths of maxillary anterior teeth in a Kurdish population. A total of 65 Kurdish dental students participated in this study. Two standardized digital photographs of the face (relaxed and smiling capture) were recorded. The interpupillary distance (IPD), inner canthal distance (ICD), interalar distance (IAD), and width of the 2 central incisors were determined by Image J software. The mesiodistal width and the combined straight-line width of the centrals, laterals, and canines were measured directly from the casts of the participants with digital calipers. A simple linear regression and the Pearson correlation coefficient were used to investigate the relationship between the particular facial measurement and the widths of the anterior teeth (α=.05). Significant correlations existed between the IPD and different tooth measurements; the highest was with the mean width of the canines (r=0.55). The proposed proportion between the IPD and the central incisor width was 6.93. The golden proportion of the ICD to the width of the central incisors and of the IAD to the straight-line width of the 6 anterior teeth could be used as a dependent parameter in Kurdish men. The IPD can be used to predict the width of anterior teeth in both sexes. In men, the width of the central incisors may be estimated from the ICD and the straight-line width of the 6 anterior teeth from the IAD. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

On the covering fraction variability in an EUV mini-BAL outflow from PG 1206+459

NASA Astrophysics Data System (ADS)

Muzahid, S.; Srianand, R.; Charlton, J.; Eracleous, M.

2016-04-01

We report on the first detection of extreme-ultraviolet (EUV) absorption variability in the Ne VIII λλ770, 780 mini-broad absorption line (mini-BAL) in the spectrum of the quasar (QSO) PG 1206+459. The observed equivalent width (EW) of the Ne VIII doublet shows a ˜4σ variation over a time-scale of 2.8 months in the QSO's rest frame. Both members of the Ne VIII doublet exhibit non-black saturation, indicating partial coverage of the continuum source. An increase in the Ne VIII covering fraction from fc = 0.59 ± 0.05 to 0.72 ± 0.03 is observed over the same period. The Ne VIII profiles are too highly saturated to be susceptible to changes in the ionization state of the absorbing gas. In fact, we do not observe any significant variation in the EW and/or column density after correcting the spectra for partial coverage. We, thus, propose transverse motions of the absorbing gas as the cause of the observed variability. Using a simple model of a transiting cloud we estimate a transverse speed of ˜1800 km s-1. For Keplerian motion, this corresponds to a distance between the absorber and the central engine of ˜1.3 pc, which places the absorber just outside the broad-line region. We further estimate a density of ˜5 × 106 cm-3 and a kinetic luminosity of ˜1043-1044 erg s-1. Such large kinetic powers suggest that outflows detected via EUV lines are potentially major contributors to active galactic nuclei feedback.

The role of cysteine 206 in allosteric inhibition of Escherichia coli citrate synthase. Studies by chemical modification, site-directed mutagenesis, and 19F NMR.

PubMed

Donald, L J; Crane, B R; Anderson, D H; Duckworth, H W

1991-11-05

Escherichia coli citrate synthase is strongly and specifically inhibited by NADH, but this inhibition can be prevented by reacting the enzyme with Ellman's reagent. We have now labeled the single reactive cysteine covalently with monobromobimane and isolated and sequenced the bimane-containing cyanogen bromide peptide and identified the cysteine as Cys-206. Modeling studies suggest that this residue is on the subunit surface, 25-30 A from the active site. Mutation of Cys-206 to serine (C206S), or of Gly-207 to alanine (E207A), weakened NADH binding and inhibition; when these mutations were present together, NADH binding was weaker by 18-fold and inhibition by 250-fold. The mutations also had small effects on substrate binding at the active site. Cys-206 of wild type enzyme and of the mutant E207A was alkylated with 1,1,1-trifluorobromoacetone and the environment of the fluorine nuclei studied by 19F NMR. With wild type enzyme, the NMR spectrum consisted of two peaks of about equal intensity but different line widths, at -8.65 ppm (line width 11.2 +/- 0.5 Hz) and -7.6 ppm (line width 57 +/- 4 Hz). As the labeled wild type citrate synthase was titrated with KCl, the narrow peak converted to the broad one. The same range of KCl concentrations was needed for this conversion as for the allosteric activation of E. coli citrate synthase. The E207A mutant gave the broader NMR peak almost exclusively. We propose that the fluorine label in wild type citrate synthase exists in two conformational states with different mobilities, exchanging slowly on the NMR time scale, and that treatment with KCl, or truncation of the Glu-207 side chain by mutagenesis, stabilizes one of these states. Consistent with this explanation is the finding that Cys-206 reacts more quickly with Ellman's reagent in the presence of KCl, and that this rate is faster yet in the E207A mutant.

Tooth display and lip position during spontaneous and posed smiling in adults.

PubMed

Van Der Geld, Pieter; Oosterveld, Paul; Berge, Stefaan J; Kuijpers-Jagtman, Anne M

2008-08-01

To analyze differences in tooth display, lip-line height, and smile width between the posed smiling record, traditionally produced for orthodontic diagnosis, and the spontaneous (Duchenne) smile of joy. The faces of 122 male participants were each filmed during spontaneous and posed smiling. Spontaneous smiles were elicited through the participants watching a comical movie. Maxillary and mandibular lip-line heights, tooth display, and smile width were measured using a digital videographic method for smile analysis. Paired sample t-tests were used to compare measurements of posed and spontaneous smiling. Maxillary lip-line heights during spontaneous smiling were significantly higher than during posed smiling. Compared to spontaneous smiling, tooth display in the (pre)molar area during posed smiling decreased by up to 30%, along with a significant reduction of smile width. During posed smiling, also mandibular lip-line heights changed and the teeth were more covered by the lower lip than during spontaneous smiling. Reduced lip-line heights, tooth display, and smile width on a posed smiling record can have implications for the diagnostics of lip-line height, smile arc, buccal corridors, and plane of occlusion. Spontaneous smiling records next to posed smiling records are therefore recommended for diagnostic purposes. Because of the dynamic nature of spontaneous smiling, it is proposed to switch to dynamic video recording of the smile.

Fano resonances of a ring-shaped "hexamer" cluster at near-infrared wavelength

NASA Astrophysics Data System (ADS)

Liu, Tong-Tong; Xia, Feng; Sun, Peng; Liu, Li-Li; Du, Wei; Li, Meng-Xue; Kong, Wei-Jin; Wan, Yong; Dong, Li-Feng; Yun, Mao-Jin

2018-03-01

Fano resonances have been studied intensely in the last decade, since it is an important way to decrease the resonance line width and enhance local electric field. However, achieving a Fano line-shape with both narrow line width and high spectral contrast ratio is still a challenge. In this paper, we theoretically predict the Fano resonance induced by the extinction of normal plane wave in a ring-shaped hexamer cluster at near-infrared wavelength. In order to obtain the narrow Fano line width and high spectral contrast ratio, the relationships between the Fano line-shape and the parameters of the nanostructure are analyzed in detail. The nanostructure is simulated by using commercial software based on finite element method. The simulation results show that when the structural parameters are optimized, the Fano line width can be narrowed down 0.028 eV with a contrast ratio of 86%, and the local electric field enhancement factor at the Fano resonance wavelength can reach to 36. Furthermore, the effective mode volume of the structure is 3.9 ×10-23m3 which is lower than the available literature. These results indicate many potential applications of the Fano resonance in multiwavelength surface-enhanced Raman scattering and biosensing.

An Improved Red Spectrum of the Methane or T Dwarf SDSS 1624+0029: The Role of the Alkali Metals.

PubMed

Liebert; Reid; Burrows; Burgasser; Kirkpatrick; Gizis

2000-04-20

A Keck II low-resolution spectrum shortward of 1 µm is presented for SDSS 1624+0029, the first field methane or T dwarf discovered in the Sloan Digital Sky Survey. Significant flux is detected down to the spectrum's short-wavelength limit of 6200 Å. The spectrum exhibits a broad absorption feature centered at 7700 Å, which we interpret as the K i lambdalambda7665, 7699 resonance doublet. The observed flux declines shortward of 7000 Å, most likely owing to the red wing of the Na i doublet. Both Cs i doublet lines are detected more strongly than in an earlier red spectrum. Neither Li i absorption nor Halpha emission are detected. An exploratory model fit to the spectrum suggests that the shape of the red spectrum can be primarily accounted for by the broad wings of the K i and Na i doublets. This behavior is consistent with the argument proffered by Burrows, Marley, & Sharp that strong alkali absorption is principally responsible for depressing T dwarf spectra shortward of 1 µm. In particular, there seems no compelling reason at this time to introduce dust or an additional opacity source in the atmosphere of the Sloan object. The width of the K i and strengths of the Cs i lines also indicate that the Sloan object is warmer than Gl 229B.

Uncovering the hidden iceberg structure of the Galactic halo

NASA Astrophysics Data System (ADS)

Moss, Vanessa A.; Di Teodoro, Enrico M.; McClure-Griffiths, Naomi M.; Lockman, Felix; Pisano, D. J.; Price, Daniel; Rees, Glen

2018-01-01

How the Milky Way gets its gas and keeps its measured star formation rate going are both long-standing mysteries in Galactic studies, with important implications for galaxy evolution across the Universe. I will present our recent discovery of two populations of neutral hydrogen (HI) in the halo of the Milky Way: 1) a narrow line-width dense population typical of the majority of bright high velocity cloud (HVC) components, and 2) a fainter, broad line-width diffuse population that aligns well with the population found in very sensitive pointings such as in Lockman et al. (2002). From our existing data, we concluded that the diffuse population likely outweighs the dense HI by a factor of 3. This discovery of diffuse HI, which appears to be prevalent throughout the halo, takes us closer to solving the Galactic mystery of accretion and reveals a gaseous neutral halo hidden from the view of most large-scale surveys. We are currently carrying out deep Parkes observations to investigate these results further, in order to truly uncover the nature of the diffuse HI and determine whether our 3:1 ratio (based on the limited existing data) is consistent with what is seen when Parkes and the 140 ft Green Bank telescope are employed at comparable sensitivity. With these data, through a combination of both known and new sightline measurements, we aim to reveal the structure of the Galactic halo in more detail than ever before.

Coherence Volume of an Optical Wave Field with Broad Frequency and Angular Spectra

NASA Astrophysics Data System (ADS)

Lyakin, D. V.; Mysina, N. Yu.; Ryabukho, V. P.

2018-03-01

We consider the sizes of a region in a three-dimensional space in which an optical wave field excites mutually coherent perturbations. We discuss the conditions under which the length of this region along the direction of propagation of the wave field and, correspondingly, its volume are determined either by the width of the frequency spectrum of the field or by the width of its angular spectrum, or by the parameters of these spectra simultaneously. We obtain expressions for estimating extremely small values of the coherence volume of the fields with a broad frequency spectrum and an extremely broad angular spectrum. Using the notion of instantaneous speckle-modulation of the wave field, we give a physical interpretation to the occurrence of a limited coherence volume of the field. The length of the spatiotemporal coherence region in which mutually coherent perturbations occur at different times is determined. The coherence volume of a wave field that illuminates an object in high-resolution microscopy with frequency broadband light is considered. The conditions for the dominant influence of the angular or frequency spectra on the longitudinal length of the coherence region are given, and the conditions for the influence of the frequency spectrum width on the transverse coherence of the wave field are examined. We show that, when using fields with broad and ultrabroad spectra in high-resolution microscopy, this influence should be taken into account.

Cavity mode-width spectroscopy with widely tunable ultra narrow laser.

PubMed

Cygan, Agata; Lisak, Daniel; Morzyński, Piotr; Bober, Marcin; Zawada, Michał; Pazderski, Eugeniusz; Ciuryło, Roman

2013-12-02

We explore a cavity-enhanced spectroscopic technique based on determination of the absorbtion coefficient from direct measurement of spectral width of the mode of the optical cavity filled with absorbing medium. This technique called here the cavity mode-width spectroscopy (CMWS) is complementary to the cavity ring-down spectroscopy (CRDS). While both these techniques use information on interaction time of the light with the cavity to determine absorption coefficient, the CMWS does not require to measure very fast signals at high absorption conditions. Instead the CMWS method require a very narrow line width laser with precise frequency control. As an example a spectral line shape of P7 Q6 O₂ line from the B-band was measured with use of an ultra narrow laser system based on two phase-locked external cavity diode lasers (ECDL) having tunability of ± 20 GHz at wavelength range of 687 to 693 nm.

Characterization of Finite Ground Coplanar Waveguide with Narrow Ground Planes

NASA Technical Reports Server (NTRS)

Ponchak, George E.; Tentzeris, Emmanouil M.; Katehi, Linda P. B.

1997-01-01

Coplanar waveguide with finite width ground planes is characterized through measurements, conformal mapping, and the Finite Difference Time Domain (FDTD) technique for the purpose of determining the optimum ground plane width. The attenuation and effective permittivity of the lines are related to its geometry. It is found that the characteristics of the Finite Ground Coplanar line (FGC) are not dependent on the ground plane width if it is greater than twice the center conductor width, but less than lambda(sub d)/8. In addition, electromagnetic field plots are presented which show for the first time that electric fields in the plane of the substrate terminate on the outer edge of the ground plane, and that the magnitude of these fields is related to the ground plane width.

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

NASA Technical Reports Server (NTRS)

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

1996-01-01

We present line profiles and profile parameters for the Narrow-Line Regions (NLRs) of six Seyfert 1 galaxies with high-ionization lines: MCG 8-11-11, Mrk 79, Mrk 704, Mrk 841, NGC 4151, and NGC 5548. The sample was chosen primarily with the goal of obtaining high-quality [Fe VII] lambda6087 and, when possible, [Fe X] lambda6374 profiles to determine if these lines are more likely formed in a physically distinct 'coronal line region' or are formed throughout the NLR along with lines of lower critical density (n(sub cr)) and/or Ionization Potential (IP). We discuss correlations of velocity shift and width with n(sub cr) and IP. In some objects, lines of high IP and/or n(sub cr) are systematically broader than those of low IP/n(sub cr). Of particular interest, however, are objects that show no correlations of line width with either IP or n(sub cr). In these objects, lines of high and low IP/n(sub cr), are remarkably similar, which is difficult to reconcile with the classical picture of the NLR, in which lines of high and low IP/n(sub cr) are formed in physically distinct regions. We argue for similar spatial extents for the flux in lines with similar profiles. Here, as well as in a modeling-oriented companion paper, we develop further an idea suggested by Moore & Cohen that objects that do and do not show line width correlations with IP/n(sub cr) can both be explained in terms of a single NLR model with only a small difference in the cloud column density distinguishing the two types of object. Overall, our objects do not show correlations between the Full Width at Half-Maximum (FWHM) and IP and/or n(sub cr). The width must be defined by a parameter that is sensitive to extended profile wings in order for the correlations to result. We present models in which FWHM correlations with IP and/or n(sub cr) result only after simulating the lower spectral resolution used in previous observational studies. The models that simulate the higher spectral resolution of our observational study produce line width correlations only if the width is defined by a parameter that is more sensitive to extended profile wings than is the FWHM. Our sample of six objects is in effect augmented by incorporating the larger sample (16 objects) of Veilleux into some of our discussion. This paper focuses on new interpretations of NLR emission-line spectra and line profiles that stem directly from the observations. Paper 2 focuses on modeling and complements this paper by illustrating explicitly the effects that spatial variations in electron density, ionization parameter, and column density have on model profiles. By comparing model profiles with the observed profiles presented here, as well as with those presented by Veilleux, Paper 2 yields insight into how the electron density, ionization parameter, and column density likely vary throughout the NLR.

Development of stable, narrow spectral line-width, fiber delivered laser source for spin exchange optical pumping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Bo; Tong, Xin; Jiang, Chenyang

2015-06-05

In this study, we developed a stable, narrow spectral line-width, fiber delivered laser source for spin exchange optical pumping. An optimized external cavity equipped with an off-the-shelf volume holographic grating narrowed the spectral line-width of a 100 W high-power diode laser and stabilized the laser spectrum. The laser spectrum showed a high side mode suppression ratio of >30 dB and good long-term stability (center wavelength drifting within ±0.002 nm during 220 h of operation). Finally, our laser is delivered by a multimode fiber with power ~70 W, center wavelength of 794.77 nm, and spectral bandwidth of ~0.12 nm.

Effects on Calculated Half-Widths and Shifts from the Line Coupling for Asymmetric-Top Molecules

NASA Technical Reports Server (NTRS)

Ma, Q.; Boulet, C.; Tipping, R. H.

2014-01-01

The refinement of the Robert-Bonamy formalism by considering the line coupling for linear molecules developed in our previous studies [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013); 140, 104304 (2014)] have been extended to asymmetric-top molecules. For H2O immersed in N2 bath, the line coupling selection rules applicable for the pure rotational band to determine whether two specified lines are coupled or not are established. Meanwhile, because the coupling strengths are determined by relative importance of off-diagonal matrix elements versus diagonal elements of the operator -iS1 -S2, quantitative tools are developed with which one is able to remove weakly coupled lines from consideration. By applying these tools, we have found that within reasonable tolerances, most of the H2O lines in the pure rotational band are not coupled. This reflects the fact that differences of energy levels of the H2O states are pretty large. But, there are several dozen strongly coupled lines and they can be categorized into different groups such that the line couplings occur only within the same groups. In practice, to identify those strongly coupled lines and to confine them into sub-linespaces are crucial steps in considering the line coupling. We have calculated half-widths and shifts for some groups, including the line coupling. Based on these calculations, one can conclude that for most of the H2O lines, it is unnecessary to consider the line coupling. However, for several dozens of lines, effects on the calculated half-widths from the line coupling are small, but remain noticeable and reductions of calculated half-widths due to including the line coupling could reach to 5%. Meanwhile, effects on the calculated shifts are very significant and variations of calculated shifts could be as large as 25%.

Effects on calculated half-widths and shifts from the line coupling for asymmetric-top molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Q.; Boulet, C.; Tipping, R. H.

2014-06-28

The refinement of the Robert-Bonamy formalism by considering the line coupling for linear molecules developed in our previous studies [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013); 140, 104304 (2014)] have been extended to asymmetric-top molecules. For H{sub 2}O immersed in N{sub 2} bath, the line coupling selection rules applicable for the pure rotational band to determine whether two specified lines are coupled or not are established. Meanwhile, because the coupling strengths are determined by relative importance of off-diagonal matrix elements versus diagonal elements of the operator −iS{sub 1} − S{sub 2}, quantitative toolsmore » are developed with which one is able to remove weakly coupled lines from consideration. By applying these tools, we have found that within reasonable tolerances, most of the H{sub 2}O lines in the pure rotational band are not coupled. This reflects the fact that differences of energy levels of the H{sub 2}O states are pretty large. But, there are several dozen strongly coupled lines and they can be categorized into different groups such that the line couplings occur only within the same groups. In practice, to identify those strongly coupled lines and to confine them into sub-linespaces are crucial steps in considering the line coupling. We have calculated half-widths and shifts for some groups, including the line coupling. Based on these calculations, one can conclude that for most of the H{sub 2}O lines, it is unnecessary to consider the line coupling. However, for several dozens of lines, effects on the calculated half-widths from the line coupling are small, but remain noticeable and reductions of calculated half-widths due to including the line coupling could reach to 5%. Meanwhile, effects on the calculated shifts are very significant and variations of calculated shifts could be as large as 25%.« less

Semi-empirical calculations of line-shape parameters and their temperature dependences for the ν6 band of CH3D perturbed by N2

NASA Astrophysics Data System (ADS)

Dudaryonok, A. S.; Lavrentieva, N. N.; Buldyreva, J.

2018-06-01

(J, K)-line broadening and shift coefficients with their temperature-dependence characteristics are computed for the perpendicular (ΔK = ±1) ν6 band of the 12CH3D-N2 system. The computations are based on a semi-empirical approach which consists in the use of analytical Anderson-type expressions multiplied by a few-parameter correction factor to account for various deviations from Anderson's theory approximations. A mathematically convenient form of the correction factor is chosen on the basis of experimental rotational dependencies of line widths, and its parameters are fitted on some experimental line widths at 296 K. To get the unknown CH3D polarizability in the excited vibrational state v6 for line-shift calculations, a parametric vibration-state-dependent expression is suggested, with two parameters adjusted on some room-temperature experimental values of line shifts. Having been validated by comparison with available in the literature experimental values for various sub-branches of the band, this approach is used to generate massive data of line-shape parameters for extended ranges of rotational quantum numbers (J up to 70 and K up to 20) typically requested for spectroscopic databases. To obtain the temperature-dependence characteristics of line widths and line shifts, computations are done for various temperatures in the range 200-400 K recommended for HITRAN and least-squares fit procedures are applied. For the case of line widths strong sub-branch dependence with increasing K is observed in the R- and P-branches; for the line shifts such dependence is stated for the Q-branch.

The broad-band x ray spectral variability of Mkn 841

NASA Technical Reports Server (NTRS)

George, I. M.; Nandra, K.; Fabian, A. C.; Turner, T. J.; Done, C.; Day, C. S. R.

1992-01-01

The results of a detailed spectral analysis of four X-ray observations of the luminous Seyfert 1.5 galaxy Mkn 841 performed using the EXOSAT and Ginga satellites over the period June 1984 to July 1990 are reported. Preliminary results from a short ROSAT PSPC observation of Mkn 841 in July 1990 are also presented. Variability is apparent in both the soft (0.1-1.0 keV) and medium (1-20 keV) energy bands. Above 1 keV, the spectra are adequately modelled by a power-law with a strong emission line of equivalent width approximately 450 eV. The energy of the line (approximately 6.4 keV) is indicative of K-shell fluorescence from neutral iron, leading to the interpretation that the line arises via X-ray illumination of cold material surrounding the source. In addition to the flux variability, the continuum shape also changes in a dramatic fashion, with variations in the apparent photon index Delta(Gamma) approximately 0.6. The large equivalent width of the emission line clearly indicates a strongly enhanced reflection component in the source, compared to other Seyferts observed with Ginga. The spectral changes are interpreted in terms of a variable power-law continuum superimposed on a flatter reflection component. For one Ginga observation, the reflected flux appears to dominate the medium energy X-ray emission, resulting in an unusually flat slope (Gamma approximately 1.0). The soft X-ray excess is found to be highly variable by a factor approximately 10. These variations are not correlated with the hard flux, but it seems likely that the soft component arises via reprocessing of the hard X-rays. We find no evidence for intrinsic absorption, with the equivalent hydrogen column density constrained to be less than or equal to few x 10(exp 20) cm(exp -2). The implications of these results for physical models for the emission regions in this and other X-ray bright Seyferts are briefly discussed.

Wave propagation in pulsar magnetospheres - Refraction of rays in the open flux zone

NASA Technical Reports Server (NTRS)

Barnard, J. J.; Arons, J.

1986-01-01

The propagation of waves through a relativistically outflowing electron-positron plasma in a very strong dipolar magnetic field, conditions expected in pulsar magnetospheres, is investigated. Halmilton's equations is derived for the propagation of rays through a plasma which is inhomogeneous in density, magnetic field directions, and Lorentz factor. These equations are solved for rays propagating through the plasmas outflowing along the 'open' dipolar field lines in which the density decreases inversely as the radius cubed and in the case where gradients transverse to the radial direction exist. In the radial case, the effects of refraction on pulse profiles, spectrum, and polarization are examined, and the effects of a transverse gradient are indicated. Attention is given to models in which the observed broad bandwidth in the radio emission has its origin in a radius to frequency map. Models with broad-band emission at a single radius are also studied. These are compared to observations of pulse width and pulse component separation as a function of frequency. The origin of 'orthogonal modes' is discussed.

Addressable-Matrix Integrated-Circuit Test Structure

NASA Technical Reports Server (NTRS)

Sayah, Hoshyar R.; Buehler, Martin G.

1991-01-01

Method of quality control based on use of row- and column-addressable test structure speeds collection of data on widths of resistor lines and coverage of steps in integrated circuits. By use of straightforward mathematical model, line widths and step coverages deduced from measurements of electrical resistances in each of various combinations of lines, steps, and bridges addressable in test structure. Intended for use in evaluating processes and equipment used in manufacture of application-specific integrated circuits.

The relaxation matrix for symmetric tops with inversion symmetry. I. Effects of line coupling on self-broadened ν1 and pure rotational bands of NH3.

PubMed

Ma, Q; Boulet, C

2016-06-14

The Robert-Bonamy formalism has been commonly used to calculate half-widths and shifts of spectral lines for decades. This formalism is based on several approximations. Among them, two have not been fully addressed: the isolated line approximation and the neglect of coupling between the translational and internal motions. Recently, we have shown that the isolated line approximation is not necessary in developing semi-classical line shape theories. Based on this progress, we have been able to develop a new formalism that enables not only to reduce uncertainties on calculated half-widths and shifts, but also to model line mixing effects on spectra starting from the knowledge of the intermolecular potential. In our previous studies, the new formalism had been applied to linear and asymmetric-top molecules. In the present study, the method has been extended to symmetric-top molecules with inversion symmetry. As expected, the inversion splitting induces a complete failure of the isolated line approximation. We have calculated the complex relaxation matrices of self-broadened NH3. The half-widths and shifts in the ν1 and the pure rotational bands are reported in the present paper. When compared with measurements, the calculated half-widths match the experimental data very well, since the inapplicable isolated line approximation has been removed. With respect to the shifts, only qualitative results are obtained and discussed. Calculated off-diagonal elements of the relaxation matrix and a comparison with the observed line mixing effects are reported in the companion paper (Paper II).

The Relaxation Matrix for Symmetric Tops with Inversion Symmetry. I. Effects of Line Coupling on Self-Broadened v (sub 1) and Pure Rotational Bands of NH3

NASA Technical Reports Server (NTRS)

Ma, Q.; Boulet, C.

2016-01-01

The Robert-Bonamy formalism has been commonly used to calculate half-widths and shifts of spectral lines for decades. This formalism is based on several approximations. Among them, two have not been fully addressed: the isolated line approximation and the neglect of coupling between the translational and internal motions. Recently, we have shown that the isolated line approximation is not necessary in developing semi-classical line shape theories. Based on this progress, we have been able to develop a new formalism that enables not only to reduce uncertainties on calculated half-widths and shifts, but also to model line mixing effects on spectra starting from the knowledge of the intermolecular potential. In our previous studies, the new formalism had been applied to linear and asymmetric-top molecules. In the present study, the method has been extended to symmetric-top molecules with inversion symmetry. As expected, the inversion splitting induces a complete failure of the isolated line approximation. We have calculated the complex relaxation matrices of selfbroadened NH3. The half-widths and shifts in the ?1 and the pure rotational bands are reported in the present paper. When compared with measurements, the calculated half-widths match the experimental data very well, since the inapplicable isolated line approximation has been removed. With respect to the shifts, only qualitative results are obtained and discussed. Calculated off-diagonal elements of the relaxation matrix and a comparison with the observed line mixing effects are reported in the companion paper (Paper II).

STRONGER REFLECTION FROM BLACK HOLE ACCRETION DISKS IN SOFT X-RAY STATES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steiner, James F.; Remillard, Ronald A.; García, Javier A.

We analyze 15,000 spectra of 29 stellar-mass black hole (BH) candidates collected over the 16 year mission lifetime of Rossi X-ray Timing Explorer using a simple phenomenological model. As these BHs vary widely in luminosity and progress through a sequence of spectral states, which we broadly refer to as hard and soft, we focus on two spectral components: the Compton power law and the reflection spectrum it generates by illuminating the accretion disk. Our proxy for the strength of reflection is the equivalent width of the Fe–K line as measured with respect to the power law. A key distinction ofmore » our work is that for all states we estimate the continuum under the line by excluding the thermal disk component and using only the component that is responsible for fluorescing the Fe–K line, namely, the Compton power law. We find that reflection is several times more pronounced (∼3) in soft compared to hard spectral states. This is most readily caused by the dilution of the Fe line amplitude from Compton scattering in the corona, which has a higher optical depth in hard states. Alternatively, this could be explained by a more compact corona in soft (compared to hard) states, which would result in a higher reflection fraction.« less

Imaging performance of annular apertures. II - Line spread functions

NASA Technical Reports Server (NTRS)

Tschunko, H. F. A.

1978-01-01

Line images formed by aberration-free optical systems with annular apertures are investigated in the whole range of central obstruction ratios. Annular apertures form lines images with central and side line groups. The number of lines in each line group is given by the ratio of the outer diameter of the annular aperture divided by the width of the annulus. The theoretical energy fraction of 0.889 in the central line of the image formed by an unobstructed aperture increases for centrally obstructed apertures to 0.932 for the central line group. Energy fractions for the central and side line groups are practically constant for all obstruction ratios and for each line group. The illumination of rectangular secondary apertures of various length/width ratios by apertures of various obstruction ratios is discussed.

Detection of Broad Hα Emission Lines in the Late-time Spectra of a Hydrogen-poor Superluminous Supernova

NASA Astrophysics Data System (ADS)

Yan, Lin; Quimby, R.; Ofek, E.; Gal-Yam, A.; Mazzali, P.; Perley, D.; Vreeswijk, P. M.; Leloudas, G.; De Cia, A.; Masci, F.; Cenko, S. B.; Cao, Y.; Kulkarni, S. R.; Nugent, P. E.; Rebbapragada, Umaa D.; Woźniak, P. R.; Yaron, O.

2015-12-01

iPTF13ehe is a hydrogen-poor superluminous supernova (SLSN) at z = 0.3434, with a slow-evolving light curve and spectral features similar to SN2007bi. It rises in 83-148 days to reach a peak bolometric luminosity of ˜1.3 × 1044 erg s-1, then decays slowly at 0.015 mag day-1. The measured ejecta velocity is ˜ 13,000 km s-1. The inferred explosion characteristics, such as the ejecta mass (70-220 M⊙), and the total radiative and kinetic energy (Erad ˜ 1051 erg, Ekin ˜ 2 × 1053 erg), are typical of slow-evolving H-poor SLSN events. However, the late-time spectrum taken at +251 days (rest, post-peak) reveals a Balmer Hα emission feature with broad and narrow components, which has never been detected before among other H-poor SLSNe. The broad component has a velocity width of ˜4500 km s-1 and a ˜300 km s-1 blueward shift relative to the narrow component. We interpret this broad Hα emission with a luminosity of ˜2 × 1041 erg s-1 as resulting from the interaction between the supernova ejecta and a discrete H-rich shell, located at a distance of ˜4 × 1016 cm from the explosion site. This interaction causes the rest-frame r-band LC to brighten at late times. The fact that the late-time spectra are not completely absorbed by the shock-ionized H-shell implies that its Thomson scattering optical depth is likely ≤1, thus setting upper limits on the shell mass ≤30 M⊙. Of the existing models, a Pulsational Pair Instability supernova model can naturally explain the observed 30 M⊙ H-shell, ejected from a progenitor star with an initial mass of (95-150) M⊙ about 40 years ago. We estimate that at least ˜15% of all SLSNe-I may have late-time Balmer emission lines.

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

NASA Astrophysics Data System (ADS)

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

2012-05-01

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

Finite Ground Coplanar (FGC) Waveguide: Characteristics and Advantages Evaluated for Radiofrequency and Wireless Communication Circuits

NASA Technical Reports Server (NTRS)

Ponchak, George E.

1999-01-01

Researchers in NASA Lewis Research Center s Electron Device Technology Branch are developing transmission lines for radiofrequency and wireless circuits that are more efficient, smaller, and make lower cost circuits possible. Traditionally, radiofrequency and wireless circuits have employed a microstrip or coplanar waveguide to interconnect the various electrical elements that comprise a circuit. Although a coplanar waveguide (CPW) is widely viewed as better than a microstrip for most applications, it too has problems. To solve these problems, NASA Lewis and the University of Michigan developed a new version of a coplanar waveguide with electrically narrow ground planes. Through extensive numerical modeling and experimental measurements, we have characterized the propagation constant of the FGC waveguide, the lumped and distributed circuit elements integrated in the FGC waveguide, and the coupling between parallel transmission lines. Although the attenuation per unit length is higher for the FGC waveguide because of higher conductor loss, the attenuation is comparable when the ground plane width is twice the center conductor width as shown in the following graph. An upper limit to the line width is derived from observations that when the total line width is greater than ld/2, spurious resonances due to the parallel plate waveguide mode are established. Thus, the ground plane width must be less than ld/4 where ld is the wavelength in the dielectric. Since the center conductor width S is typically less than l/10 to maintain good transverse electromagnetic mode characteristics, it follows that a ground plane width of B = 2S would also be electrically narrow. Thus, we can now treat the ground strips of the FGC waveguide the same way that the center conductor is treated.

Low Temperature Photoluminescence of PVT Grown ZnSe and ZnSeTe

NASA Technical Reports Server (NTRS)

Wang, Ling Jun; Su, Ching-Hua; Lehoczky, S. L.

1999-01-01

ZnSe and ZnSeTe single crystals were grown by physical vapor transport (PVT) technique horizontally and vertically. The grown ZnSe and ZnSeTe single crystals were characterized by low temperature photoluminescence at 5 to 10 K using the 3.4 eV emission of an argon laser. The intensity of the sharp near band edge defect lines at 2.799, 2.783 eV and the intrinsic free exciton line at 2.802 eV were mapped on various crystal surfaces with different orientations to the gravitational field. The results show the effects of gravity vector orientation on the defect segregation. Comparison of the photoluminescence spectra of the ZeSe crystal before and after annealing in the Zn vapor shows that the 2.783 eV line of ZnSe crystal is related to the zinc vacancy. The photoluminescence spectra of the ternary ZnSeTe crystal were characterized by a single broad band from 2.2 to 2.4 eV, with a Full Width at Half Maximum (FWHM) of about 100 meV. The temperature dependence of the peak position and intensity were determined from 7 to 150 K.

THE FORMATION OF IRIS DIAGNOSTICS. VIII. IRIS OBSERVATIONS IN THE C ii 133.5 nm MULTIPLET

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rathore, Bhavna; Pereira, Tiago M. D.; Carlsson, Mats

The C ii 133.5 nm multiplet has been observed by NASA’s Interface Region Imaging Spectrograph (IRIS) in unprecedented spatial resolution. The aims of this work are to characterize these new observations of the C ii lines, place them in context with previous work, and to identify any additional value the C ii lines bring when compared with other spectral lines. We make use of wide, long exposure IRIS rasters covering the quiet Sun and an active region. Line properties such as velocity shift and width are extracted from individual spectra and analyzed. The lines have a variety of shapes (mostlymore » single-peak or double-peak), are strongest in active regions and weaker in the quiet Sun. The ratio between the 133.4 and 133.5 nm components is always less than 1.8, indicating that their radiation is optically thick in all locations. Maps of the C ii line widths are a powerful new diagnostic of chromospheric structures, and their line shifts are a robust velocity diagnostic. Compared with earlier quiet Sun observations, we find similar absolute intensities and mean line widths, but smaller redshifts; this difference can perhaps be attributed to differences in spectral resolution and spatial coverage. The C ii intensity maps are somewhat similar to those of transition region lines, but also share some features with chromospheric maps such as those from the Mg ii k line, indicating that they are formed between the upper chromosphere and transition region. C ii intensity, width, and velocity maps can therefore be used to gather additional information about the upper chromosphere.« less

Slitless Solar Spectroscopy

NASA Technical Reports Server (NTRS)

Davila, Joseph M.; Jones, Sahela

2011-01-01

Spectrographs have traditionally suffered from the inability to obtain line intensities, widths, and Doppler shifts over large spatial regions of the Sun quickly because of the narrow instantaneous field of view. This has limited the spectroscopic analysis of rapidly varying solar features like, flares, CME eruptions, coronal jets, and reconnection regions. Imagers have provided high time resolution images of the full Sun with limited spectral resolution. In this paper we present recent advances in deconvolving spectrally dispersed images obtained through broad slits. We use this new theoretical formulation to examine the effectiveness of various potential observing scenarios, spatial and spectral resolutions, signal to noise ratio, and other instrument characteristics. This information will lay the foundation for a new generation of spectral imagers optimized for slitless spectral operation, while retaining the ability to obtain spectral information in transient solar events.

Investigation of optical properties and local structure of Gd3+ doped nano-crystalline GeSe2

NASA Astrophysics Data System (ADS)

Hantour, Hanan Hassan

2017-04-01

Pure and Gd-doped nano-crystalline GeSe2 were prepared by the melt-quenching technique. Structure analysis using Rietveld program suggests monoclinic structure for both virgin and doped samples with nano-particle size 41 nm for GeSe2 and 48 nm for Gd-doped sample. A wide optical band gap as estimated from absorbance measurements is 4.1 and 4.8 eV for pure and doped samples in accordance with the confinement effects. Raman spectra show two unresolved components at ˜202 cm-1 with broad line width. Also, well identified low intensity (υ < 145 cm-1) and high intensity (υ > 250 cm-1) bands are detected. For Gd-doped sample, the main band is shifted to lower energies and its full width at half maximum (FWHM) is reduced by ˜50% accompanied by an intensity increase of about ˜17 fold times. The photoluminescence analysis of the pure sample shows a main emission band at ˜604 nm. This band is split into two separated bands with higher intensity. The detected emission bands at wavelength >650 nm are assigned to transmission from 6GJ to the different 6PJ terms.

VUV spectroscopic study of the ? state of H2

NASA Astrophysics Data System (ADS)

Dickenson, G. D.; Ubachs, W.

2014-04-01

Spectral lines, probing rotational quantum states J‧ = 0, 1, 2 of the inner well vibrations (υ‧ ≤ 8) in the ? state of molecular hydrogen, were recorded in high resolution using a vacuum ultraviolet Fourier transform absorption spectrometer in the wavelength range 73-86 nm. Accurate line positions and predissociation widths are determined from a fit to the absorption spectra. Improved values for the line positions are obtained, while the predissociation widths agree well with previous investigations.

High-Resolution Spectroscopy of [Ne II] Emission from AA Tau and GM Aur

NASA Astrophysics Data System (ADS)

Najita, Joan R.; Doppmann, Greg W.; Bitner, Martin A.; Richter, Matthew J.; Lacy, John H.; Jaffe, Daniel T.; Carr, John S.; Meijerink, Rowin; Blake, Geoffrey A.; Herczeg, Gregory J.; Glassgold, Alfred E.

2009-05-01

We present high-resolution (R = 80,000) spectroscopy of [Ne II] emission from two young stars, GM Aur and AA Tau, which have moderate to high inclinations. The emission from both sources appears centered near the stellar velocity and is broader than the [Ne II] emission measured previously for the face-on disk system TW Hya. These properties are consistent with a disk origin for the [Ne II] emission we detect, with disk rotation (rather than photoevaporation or turbulence in a hot disk atmosphere) playing the dominant role in the origin of the line width. In the non-face-on systems, the [Ne II] emission is narrower than the CO fundamental emission from the same sources. If the widths of both diagnostics are dominated by Keplerian rotation, this suggests that the [Ne II] emission arises from larger disk radii on average than does the CO emission. The equivalent width of the [Ne II] emission we detect is less than that of the spectrally unresolved [Ne II] feature in the Spitzer spectra of the same sources. Variability in the [Ne II] emission or the mid-infrared continuum, a spatially extended [Ne II] component, or a very (spectrally) broad [Ne II] component might account for the difference in the equivalent widths. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministrio da Cincia e Tecnologia (Brazil), and SECYT (Argentina).

Absolute intensities and self-, N2-, and air-broadened Lorentz halfwidths for selected lines in the nu3 band of (C-12)H3D from measurements with a tunable diode laser spectrometer

NASA Technical Reports Server (NTRS)

Malathy Devi, V.; Benner, D. C.; Rinsland, C. P.; Smith, M. A. H.; Thakur, K. B.

1986-01-01

Absolute intensities and self-, air- and N2-broadened half-widths have been determined for the first time for individual lines in the nu3(A1) band of (C-12)H3D near 7.6 microns from measurements of individual vibration-rotation lines using a tunable diode laser spectrometer. The intensity measurements are believed to be accurate to within three percent. Within experimental uncertainties, equal broadening efficiencies are found for both air and nitrogen. Self-broadened half-widths determined for three transitions yield an average half-width value of 0.803 + or -0.0010/cm/atm at 296 K.

The Distance to the Coma Cluster from the Tully--Fisher Relation

NASA Astrophysics Data System (ADS)

Herter, T.; Vogt, N. P.; Haynes, M. P.; Giovanelli, R.

1993-12-01

As part of a survey to determine the distances to nearby (z < .04) Abell clusters via application of the Tully--Fisher (TF) relation, we have obtained 21 cm HI line widths, optical rotation curves and photometric I--band CCD images of galaxies within and near the Coma cluster. Because spiral galaxies within the cluster itself are HI deficient and thus are detected marginally or not at all in HI, distance determinations using only the radio TF relation exclude true cluster members. Our sample includes eight HI deficient galaxies within 1.5 degrees of the cluster center, for which optical velocity widths are derived from their Hα and [NII] rotation curves. The 21 cm line widths have been extracted using a new algorithm designed to optimize the measurement for TF applications, taking into account the effects of spectral resolution and smoothing. The optical width is constructed from the velocity histogram, and is therefore a global value akin to the HI width. A correction for turbulent broadening of the HI is derived from comparison of the optical and HI widths. Using a combined sample of 260 galaxies in 11 clusters and an additional 30 field objects at comparable distances, we have performed a calibration of the radio and optical analogs of the TF relation. Preliminary results show a clear linear relationship with a small offset between optical and radio widths, and good agreement in deriving Tully--Fisher distances to clusters. Our Coma sample consists of 28 galaxies with optical widths and 42 with HI line widths, with an overlapping set of 20 galaxies. We will present the data on the Coma cluster, and discuss the results of our analysis.

Electrically-pumped, broad-area, single-mode photonic crystal lasers.

PubMed

Zhu, Lin; Chak, Philip; Poon, Joyce K S; DeRose, Guy A; Yariv, Amnon; Scherer, Axel

2007-05-14

Planar broad-area single-mode lasers, with modal widths of the order of tens of microns, are technologically important for high-power applications and improved coupling efficiency into optical fibers. They may also find new areas of applications in on-chip integration with devices that are of similar size scales, such as for spectroscopy in microfluidic chambers or optical signal processing with micro-electromechanical systems. An outstanding challenge is that broad-area lasers often require external means of control, such as injection-locking or a frequency/spatial filter to obtain single-mode operation. In this paper, we propose and demonstrate effective index-guided, large-area, edge-emitting photonic crystal lasers driven by pulsed electrical current injection at the optical telecommunication wavelength of 1550 nm. By suitable design of the photonic crystal lattice, our lasers operate in a single mode with a 1/e(2) modal width of 25 microm and a length of 600 microm.

Hemispheric differentiation and category width.

PubMed

Huang, M S

1979-12-01

This study concerns the relationship between a cognitive style dimension, category width, and hemispheric differentiation. When lists of word pairs were presented simultaneously in a dichotic listening task to broad and narrow categorisers (all female, right-handed), both groups of subjects recalled more words presented to the right ear than those presented to the left ear; indicating left hemisphere's superiority in verbal processing. Both broad and narrow categorisers recalled a similar number of words in the right ear (left hemisphere), but the former recalled significantly more words in the left ear than did the latter. This finding is interpreted as meaning that narrow categorisers rely predominantly on the left hemisphere in verbal processing, and that in comparison with narrow categories, there is greater right hemispheric involvement in processing in the case of broad categorisers. The implication of this finding in terms of the differential processing strategies adopted by the two groups of individuals is discussed.

Characterization of the Coupling Between Adjacent Finite Ground Coplanar (FGC) Waveguides

NASA Technical Reports Server (NTRS)

Ponchak, George E.; Katehi, Linda P. B.; Tentzeris, Emmanouil M.

1997-01-01

Coupling between adjacent Finite Ground Coplanar (FGC) waveguides as a function of the line geometry is presented for the first time. A two Dimension-Finite Difference Time Domain (2D-FDTD) analysis and measurements are used to show that the coupling decreases as the line to line separation and the grOUnd plane width increases. Furthermore, it is shown that for a given spacing between the center lines of two FGC lines, the coupling is lower if the ground plane width is smaller Lastly, electric field plots generated from the 2D-FDTD technique are presented which demonstrate a strong slotline mode is established in the coupled FGC line.

Dielectric image line groove antennas for millimeterwaves

NASA Astrophysics Data System (ADS)

Solbach, K.; Wolff, I.

Grooves in the ground plane of dielectric image lines are proposed as a new radiating structure. A figure is included showing the proposed groove structure as a discontinuity in a dielectric image line. A wave incident on the dielectric image line is partly reflected by the discontinuity, partly transmitted across the groove, and partly radiated into space above the line. In a travelling-wave antenna, a number of grooves are arranged below a dielectric guide, with spacings around one guide wavelength to produce a beam in the upper half space. A prescribed aperture distribution can be effected by tapering the series radiation resistance of the grooves. This can be done by adjusting the depths of the grooves with a constant width or by varying the widths of the grooves with a constant depth. Attention is also given to circular grooves. Here, the widths of the holes are chosen so that they can be considered as waveguides operating far below the cut-off frequency of the fundamental circular waveguide mode.

Relating Line Width and Optical Depth for CO Emission in the Large Mgellanic Cloud

NASA Astrophysics Data System (ADS)

Wojciechowski, Evan; Wong, Tony; Bandurski, Jeffrey; MC3 (Mapping CO in Molecular Clouds in the Magellanic Clouds) Team

2018-01-01

We investigate data produced from ALMA observations of giant molecular clouds (GMCs) located in the Large Magellanic Cloud (LMC), using 12CO(2–1) and 13CO(2–1) emission. The spectral line width is generally interpreted as tracing turbulent rather than thermal motions in the cloud, but could also be affected by optical depth, especially for the 12CO line (Hacar et al. 2016). We compare the spectral line widths of both lines with their optical depths, estimated from an LTE analysis, to evaluate the importance of optical depth effects. Our cloud sample includes two regions recently published by Wong et al. (2017, submitted): the Tarantula Nebula or 30 Dor, an HII region rife with turbulence, and the Planck cold cloud (PCC), located in a much calmer environment near the fringes of the LMC. We also include four additional LMC clouds, which span intermediate levels of star formation relative to these two clouds, and for which we have recently obtained ALMA data in Cycle 4.

Vacuum ultraviolet molecular nitrogen photoabsorption cross sections for planetary atmospheric transmission models

NASA Astrophysics Data System (ADS)

Stark, G.; Smith, P. L.; Yoshino, K.; Rufus, J.; Huber, K. P.

2001-11-01

The analyses of VUV occultation measurements of the N2-rich atmospheres of Titan and Triton are hampered by the lack of fundamental spectroscopic data for N2. In particular, there is a need for reliable photoabsorption f-values and line widths for the ~ 100 electronic bands of N2 in the 80 to 100 nm wavelength region. As part of our continuing program of laboratory measurements and analyses of the N2 VUV absorption spectrum, we present the results of new measurements of individual line strengths and widths in selected bands. These results indicate that within a number of individual bands there are significant departures from the predicted line strength distributions based on isolated band models. New line width measurements in the 95 to 100 nm region are also presented and compared to other values found in the literature. We have continued to compile on-line molecular spectroscopic atlas based on our N2 laboratory data: http://cfa-www.harvard.edu/amdata/ampdata/N2ARCHIVE/n2home.html. The archive includes published and unpublished 14N2, 14N15N, and 15N2 line lists and spectroscopic identifications, excited state energy levels, band and line f-values, a summary of published band f-value and line width measurements, and a cross-referenced summary of the relevant N2 literature. The listings are searchable by wavelength interval or band identification and are suitable for down-loading in a convenient format. We gratefully acknowledge funding support from NASA grant NAG5-9059 and the Smithsonian Institution Atherton-Seidel grant program.

Dependence with the oxidation state of X-ray transition energies, intensities and natural line widths of CrKβ spectra

NASA Astrophysics Data System (ADS)

Torres Deluigi, M.; Tirao, G.; Stutz, G.; Cusatis, C.; Riveros, J. A.

2006-06-01

The Kβ emission spectrum of chromium was experimentally analyzed in different compounds and compared with previous data. Measurements of whole Kβ spectra were performed with a wavelength dispersive commercial XRF equipment. To study possible effects of the chemical state in the width and position of the main Kβ 1,3 line, high resolution measurements were also performed. In the latter measurements, a spectrometer based on a backdiffracting crystal analyzer with spherical focalization and synchrotron radiation monochromatic excitation was used. Kβ 1,3 line shifts in relation to metallic Cr were observed, both to higher energies (≅+1 eV) for Cr III and to lower energies (≅-0.5 eV) for Cr VI. It was also found that the natural width of CrKβ 1,3 line, the ionization energy of the 3p orbital of Cr, and the relative intensities of Kβ″ and Kβ 2,5 lines with respect to the main Kβ 1,3 line increase as the oxidation state increases. The use of these features as an index for chemical state analysis is discussed.

Experimental and theoretical investigation of the rocking curves measured for Mo K α X-ray characteristic lines in the double-crystal nondispersive scheme

NASA Astrophysics Data System (ADS)

Marchenkov, N. V.; Chukhovskii, F. N.; Blagov, A. E.

2015-03-01

The rocking curves (RCs) for Mo K α1 h Mo K α2 characteristic X-ray lines have been experimentally and theoretically studied in the nondispersive scheme of an X-ray double-crystal TPC-K diffractometer. The results of measurements and theoretical calculations of double-crystal RCs for characteristic X-rays from tubes with a molybdenum anode and different widths of slits show that a decrease in the slit width leads to an increase in the relative contribution of the Mo K α2-line RC in comparison with the intensity of the tails of the Mo K α1-line RC. It is shown that the second peak of the Mo K α2 line becomes increasingly pronounced in the tail of the Mo K α1-line RC with a decrease in the slit width. Two plane-parallel Si plates (input faces {110}, diffraction vector h <220>) were used as a monochromator crystal and a sample. The results of measuring double-crystal RCs are in good agreement with theoretical calculations.

Wavelength stabilized multi-kW diode laser systems

NASA Astrophysics Data System (ADS)

Köhler, Bernd; Unger, Andreas; Kindervater, Tobias; Drovs, Simon; Wolf, Paul; Hubrich, Ralf; Beczkowiak, Anna; Auch, Stefan; Müntz, Holger; Biesenbach, Jens

2015-03-01

We report on wavelength stabilized high-power diode laser systems with enhanced spectral brightness by means of Volume Holographic Gratings. High-power diode laser modules typically have a relatively broad spectral width of about 3 to 6 nm. In addition the center wavelength shifts by changing the temperature and the driving current, which is obstructive for pumping applications with small absorption bandwidths. Wavelength stabilization of high-power diode laser systems is an important method to increase the efficiency of diode pumped solid-state lasers. It also enables power scaling by dense wavelength multiplexing. To ensure a wide locking range and efficient wavelength stabilization the parameters of the Volume Holographic Grating and the parameters of the diode laser bar have to be adapted carefully. Important parameters are the reflectivity of the Volume Holographic Grating, the reflectivity of the diode laser bar as well as its angular and spectral emission characteristics. In this paper we present detailed data on wavelength stabilized diode laser systems with and without fiber coupling in the spectral range from 634 nm up to 1533 nm. The maximum output power of 2.7 kW was measured for a fiber coupled system (1000 μm, NA 0.22), which was stabilized at a wavelength of 969 nm with a spectral width of only 0.6 nm (90% value). Another example is a narrow line-width diode laser stack, which was stabilized at a wavelength of 1533 nm with a spectral bandwidth below 1 nm and an output power of 835 W.

Analysis of the 3C 445 soft X-ray spectrum as observed by Chandra high-energy gratings

NASA Astrophysics Data System (ADS)

Dong, Fu-Tong; Shao, Shu-Hua; Cheng, Yan; Zeng, Jiao-Long

2018-05-01

We present a detailed analysis of the soft X-ray emission of 3C 445 using an archival Chandra High Energy Transmission Grating (HETG) spectrum. Highly-ionized H- and He-like Mg, Si and S lines, as well as a resolved low-ionized Si Kα line, are detected in the high resolution spectrum. The He-like triplets of Mg and Si are resolved into individual lines, and the calculated R ratios indicate a high density for the emitter. The low values of G ratios indicate the lines originate from collisionally ionized plasmas. However, the detection of a resolved narrow Ne X radiative recombination continua (RRC) feature in the spectrum seems to prefer a photoionized environment. The spectrum is subsequently modeled with a photoionization model, and the results are compared with those of a collisional model. Through a detailed analysis of the spectrum, we exclude a collisional origin for these emission lines. A one-component photoionization model provides a great fit to the emission features. The best-fit parameters are {log} ξ ={3.3}-0.3+0.4 erg cm s‑1, {n}{{H}}={5}-4.5+15× {10}10 cm‑3 and {N}{{H}}={2.5}-1.7+3.8× {10}20 cm‑2. According to the calculated high density for the emitter, the measured velocity widths of the emission lines and the inferred radial distance (6 × 1014 – 8 × 1015 cm), we suggest the emission lines originating from matter are located in the broad line region (BLR).

Unilateral compatibility and genotypic difference in crossability in interspecific hybridization between Dianthus caryophyllus L. and Dianthus japonicus Thunb.

PubMed

Nimura, M; Kato, J; Mii, M; Morioka, K

2003-05-01

Reciprocal interspecific crosses were carried out between six lines of Dianthus caryophyllus L. and one line of Dianthus japonicus Thunb. Although no seed was set when D. japonicus was used as the seed parent, six seedlings were successfully obtained from 2,380 immature ovules by applying the embryo-rescue technique. However, they showed seed parent-like morphology and no evidence for the hybridity by flow cytometry and RAPD analyses. When six lines of D. caryophyllus were used as seed parents, a total of 192 seedlings were successfully obtained without using the embryo-rescue technique. Among these seedlings, 12 out of 25 progenies obtained from the carnation line '98sp1651' were confirmed to be the hybrids. The remaining 13 progenies of this line, and the total 167 progenies obtained from the other carnation lines, had carnation-like morphology without any evidence of hybridity by flow cytometry and RAPD analyses. The progenies confirmed as hybrids had intermediate characters of the parents with respect to leaf width and flower size, but they had a uniform flower color, reddish purple, which was different from that of either parent. Since the hybrids obtained in the present study have some profitable characters such as vigorous growth in summer time, upright robust stem, broad leaves and early flowering, they are expected to be used for the breeding of carnation which is suitable for growing under the Japanese climate.

Stark width regularities within spectral series of the lithium isoelectronic sequence

NASA Astrophysics Data System (ADS)

Tapalaga, Irinel; Trklja, Nora; Dojčinović, Ivan P.; Purić, Jagoš

2018-03-01

Stark width regularities within spectral series of the lithium isoelectronic sequence have been studied in an approach that includes both neutrals and ions. The influence of environmental conditions and certain atomic parameters on the Stark widths of spectral lines has been investigated. This study gives a simple model for the calculation of Stark broadening data for spectral lines within the lithium isoelectronic sequence. The proposed model requires fewer parameters than any other model. The obtained relations were used for predictions of Stark widths for transitions that have not yet been measured or calculated. In the framework of the present research, three algorithms for fast data processing have been made and they enable quality control and provide verification of the theoretically calculated results.

Accretion Rate: An Axis Of Agn Unification

NASA Astrophysics Data System (ADS)

Trump, Jonathan R.; Impey, C. D.; Kelly, B. C.

2011-01-01

We show how accretion rate governs the physical properties of broad-line, narrow-line, and lineless active galactic nuclei (AGNs). We avoid the systematic errors plaguing previous studies of AGN accretion rate by using accurate accretion luminosities from well-sampled multiwavelength SEDs from the Cosmic Evolution Survey (COSMOS), and accurate black hole masses derived from virial scaling relations (for broad-line AGNs) or host-AGN relations (for narrow-line and lineless AGNs). In general, broad emission lines are present only at the highest accretion rates (L/L_Edd>0.01), and these rapidly accreting AGNs are observed as broad-line AGNs or possibly as obscured narrow-line AGNs. Narrow-line and lineless AGNs at lower specific accretion rates (L/L_Edd<0.01) are unobscured and yet lack a broad line region. The disappearance of the broad emission lines is caused by an expanding radiatively inefficient accretion flow (RIAF) at the inner radius of the accretion disk. The presence of the RIAF also drives L/L_Edd<0.01 narrow-line and lineless AGNs to be 10-100 times more radio-luminous than broad-line AGNs, since the unbound nature of the RIAF means it is easier to form a radio outflow. The IR torus signature also tends to become weaker or disappear from L/L_Edd<0.01 AGNs, although there may be additional mid-IR synchrotron emission associated with the RIAF. Together these results suggest that specific accretion rate is an important physical "axis" of AGN unification, described by a simple model.

Method for Assessment of Changes in the Width of Cracks in Cement Composites with Use of Computer Image Processing and Analysis

NASA Astrophysics Data System (ADS)

Tomczak, Kamil; Jakubowski, Jacek; Fiołek, Przemysław

2017-06-01

Crack width measurement is an important element of research on the progress of self-healing cement composites. Due to the nature of this research, the method of measuring the width of cracks and their changes over time must meet specific requirements. The article presents a novel method of measuring crack width based on images from a scanner with an optical resolution of 6400 dpi, subject to initial image processing in the ImageJ development environment and further processing and analysis of results. After registering a series of images of the cracks at different times using SIFT conversion (Scale-Invariant Feature Transform), a dense network of line segments is created in all images, intersecting the cracks perpendicular to the local axes. Along these line segments, brightness profiles are extracted, which are the basis for determination of crack width. The distribution and rotation of the line of intersection in a regular layout, automation of transformations, management of images and profiles of brightness, and data analysis to determine the width of cracks and their changes over time are made automatically by own code in the ImageJ and VBA environment. The article describes the method, tests on its properties, sources of measurement uncertainty. It also presents an example of application of the method in research on autogenous self-healing of concrete, specifically the ability to reduce a sample crack width and its full closure within 28 days of the self-healing process.

Hints of correlation between broad-line and radio variations for 3C 120

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2014-01-01

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

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

NASA Astrophysics Data System (ADS)

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

2011-12-01

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

SDSS J211852.96-073227.5: a new γ-ray flaring narrow-line Seyfert 1 galaxy

NASA Astrophysics Data System (ADS)

Yang, Hui; Yuan, Weimin; Yao, Su; Li, Ye; Zhang, Jin; Zhou, Hongyan; Komossa, S.; Liu, He-Yang; Jin, Chichuan

2018-07-01

We report on the identification of a new γ-ray-emitting narrow-line Seyfert 1 (NLS1) galaxy, SDSS J211852.96-073227.5 (hereinafter J2118-0732). The galaxy, at a redshift of 0.26, is associated with a radio source of flat/inverted spectrum at high radio frequencies. The analysis of its optical spectrum obtained in the Sloan Digital Sky Survey (SDSS) revealed a small linewidth of the broad component of the Hβ line (full width at half-maximum = 1585 km s-1), making it a radio-loud NLS1 galaxy - an intriguing class of active galactic nuclei with exceptional multiwavelength properties. A new γ-ray source centred at J2118-0732 was sporadically detected during 2009-2013 in form of flares by the Fermi-LAT. Our XMM-Newton observations revealed a flat X-ray spectrum described by a simple power law, and a flux variation by a factor of ˜2.5 in five months. The source also shows intraday variability in the infrared band. Its broad-band spectral energy distribution can be modelled by emission from a simple one-zone leptonic jet model, and the flux drop from infrared to X-rays in five months can be explained by changes of the jet parameters, though the exact values may be subject to relatively large uncertainties. With the NLS1-blazar composite nucleus, the clear detection of the host galaxy, and the synchronous variations in the multiwavelength fluxes, J2118-0732 provides a new perspective on the formation and evolution of relativistic jets under the regime of relatively small black hole masses and high accretion rates.

Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rumbaugh, N.; Shen, Yue; Morganson, Eric

2018-02-20

We perform a systematic search for long-term extreme variability quasars (EVQs) in the overlapping Sloan Digital Sky Survey (SDSS) and 3-Year Dark Energy Survey (DES) imaging, which provide light curves spanning more than 15 years. We identified ~1000 EVQs with a maximum g band magnitude change of more than 1 mag over this period, about 10% of all quasars searched. The EVQs have L_bol~10^45-10^47 erg/s and L/L_Edd~0.01-1. Accounting for selection effects, we estimate an intrinsic EVQ fraction of ~30-50% among all g<~22 quasars over a baseline of ~15 years. These EVQs are good candidates for so-called "changing-look quasars", where amore » spectral transition between the two types of quasars (broad-line and narrow-line) is observed between the dim and bright states. We performed detailed multi-wavelength, spectral and variability analyses for the EVQs and compared to their parent quasar sample. We found that EVQs are distinct from a control sample of quasars matched in redshift and optical luminosity: (1) their UV broad emission lines have larger equivalent widths; (2) their Eddington ratios are systematically lower; and (3) they are more variable on all timescales. The intrinsic difference in quasar properties for EVQs suggest that internal processes associated with accretion are the main driver for the observed extreme long-term variability. However, despite their different properties, EVQs seem to be in the tail of a continuous distribution of quasar properties, rather than standing out as a distinct population. We speculate that EVQs are normal quasars accreting at relatively low accretion rates, where the accretion flow is more likely to experience instabilities that drive the factor of few changes in flux on multi-year timescales.« less

RAMAN SCATTERED He II {lambda}4332 IN THE SYMBIOTIC STAR V1016 CYGNI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Hee-Won

Raman scattering of He II line photons with atomic hydrogen is important in studying the mass loss processes in many symbiotic stars and a number of young planetary nebulae. We calculate the scattering cross sections and branching ratios associated with the Raman scattered He II {lambda}4332 feature formed through inelastic scattering of He II {lambda}949 with a hydrogen atom. At the line center of He II {lambda}949, the total scattering cross section is computed to be {sigma}{sub tot} = 2.5 Multiplication-Sign 10{sup -22} cm{sup 2}, and the branching ratio into the level 2s is 0.12. We also present a high-resolutionmore » spectrum of the symbiotic star V1016 Cygni obtained with the 1.8 m telescope at Mt. Bohyun to investigate the Raman scattering origin of the broad feature blueward of He II {lambda}4338. Based on the atomic calculation, we perform Monte Carlo calculations for the line formation. The scattering region is assumed to be a part of a uniform spherical shell that subtends a solid angle {Delta}{Omega} = {pi} steradian with a neutral column density N{sub HI} = 1.0 x 10{sup 21} cm{sup -2}. By adding a far-UV continuum around He II {lambda}949 normalized by the equivalent width of He II {lambda}949 to be 2.3 Angstrom-Sign , we obtain a good fit for both the Raman scattered He II {lambda}4332 and the broad wings around H{gamma}. Our analysis of the Raman feature blueward of H{gamma} in V1016 Cyg is consistent with the previous study of the Raman features blueward of H{alpha} and H{beta} by Jung and Lee.« less

The nature of water within bacterial spores: protecting life in extreme environments

NASA Astrophysics Data System (ADS)

Rice, Charles V.; Friedline, Anthony; Johnson, Karen; Zachariah, Malcolm M.; Thomas, Kieth J., III

2011-10-01

The bacterial spore is a formidable container of life, protecting the vital contents from chemical attack, antimicrobial agents, heat damage, UV light degradation, and water dehydration. The exact role of the spore components remains in dispute. Nevertheless, water molecules are important in each of these processes. The physical state of water within the bacterial spore has been investigated since the early 1930's. The water is found two states, free or bound, in two different areas, core and non-core. It is established that free water is accessible to diffuse and exchange with deuterated water and that the diffusible water can access all areas of the spore. The presence of bound water has come under recent scrutiny and has been suggested the water within the core is mobile, rather than bound, based on the analysis of deuterium relaxation rates. Using an alternate method, deuterium quadrupole-echo spectroscopy, we are able to distinguish between mobile and immobile water molecules. In the absence of rapid motion, the deuterium spectrum of D2O is dominated by a broad line, whose line shape is used as a characteristic descriptor of molecular motion. The deuterium spectrum of bacterial spores reveals three distinct features: the broad peak of immobilized water, a narrow line of water in rapid motion, and a signal of intermediate width. This third signal is assigned this peak from partially deuterated proteins with the spore in which N-H groups have undergone exchange with water deuterons to form N-D species. As a result of these observations, the nature of water within the spore requires additional explanation to understand how the spore and its water preserve life.

The Sloan Digital Sky Survey Reverberation Mapping Project: Hα and Hβ Reverberation Measurements from First-year Spectroscopy and Photometry

NASA Astrophysics Data System (ADS)

Grier, C. J.; Trump, J. R.; Shen, Yue; Horne, Keith; Kinemuchi, Karen; McGreer, Ian D.; Starkey, D. A.; Brandt, W. N.; Hall, P. B.; Kochanek, C. S.; Chen, Yuguang; Denney, K. D.; Greene, Jenny E.; Ho, L. C.; Homayouni, Y.; I-Hsiu Li, Jennifer; Pei, Liuyi; Peterson, B. M.; Petitjean, P.; Schneider, D. P.; Sun, Mouyuan; AlSayyad, Yusura; Bizyaev, Dmitry; Brinkmann, Jonathan; Brownstein, Joel R.; Bundy, Kevin; Dawson, K. S.; Eftekharzadeh, Sarah; Fernandez-Trincado, J. G.; Gao, Yang; Hutchinson, Timothy A.; Jia, Siyao; Jiang, Linhua; Oravetz, Daniel; Pan, Kaike; Paris, Isabelle; Ponder, Kara A.; Peters, Christina; Rogerson, Jesse; Simmons, Audrey; Smith, Robyn; Wang, Ran

2017-12-01

We present reverberation mapping results from the first year of combined spectroscopic and photometric observations of the Sloan Digital Sky Survey Reverberation Mapping Project. We successfully recover reverberation time delays between the g+i band emission and the broad Hβ emission line for a total of 44 quasars, and for the broad Hα emission line in 18 quasars. Time delays are computed using the JAVELIN and CREAM software and the traditional interpolated cross-correlation function (ICCF): using well-defined criteria, we report measurements of 32 Hβ and 13 Hα lags with JAVELIN, 42 Hβ and 17 Hα lags with CREAM, and 16 Hβ and eight Hα lags with the ICCF. Lag values are generally consistent among the three methods, though we typically measure smaller uncertainties with JAVELIN and CREAM than with the ICCF, given the more physically motivated light curve interpolation and more robust statistical modeling of the former two methods. The median redshift of our Hβ-detected sample of quasars is 0.53, significantly higher than that of the previous reverberation mapping sample. We find that in most objects, the time delay of the Hα emission is consistent with or slightly longer than that of Hβ. We measure black hole masses using our measured time delays and line widths for these quasars. These black hole mass measurements are mostly consistent with expectations based on the local {M}{BH}-{σ }* relationship, and are also consistent with single-epoch black hole mass measurements. This work increases the current sample size of reverberation-mapped active galaxies by about two-thirds and represents the first large sample of reverberation mapping observations beyond the local universe (z < 0.3).

Power supply circuit for an ion engine sequentially operated power inverters

NASA Technical Reports Server (NTRS)

Cardwell, Jr., Gilbert I. (Inventor)

2000-01-01

A power supply circuit for an ion engine suitable for a spacecraft has a voltage bus having input line and a return line. The power supply circuit includes a pulse width modulation circuit. A plurality of bridge inverter circuits is coupled to the bus and the pulse width modulation circuit. The pulse width modulation circuit generates operating signals having a variable duty cycle. Each bridge inverter has a primary winding and a secondary winding. Each secondary winding is coupled to a rectifier bridge. Each secondary winding is coupled in series with another of the plurality of rectifier bridges.

Isotopic niches support the resource breadth hypothesis

USGS Publications Warehouse

Rader, Jonathan A.; Newsome, Seth D.; Sabat, Pablo; Chesser, R. Terry; Dillon, Michael E.; Martinez del Rio, Carlos

2017-01-01

Because a broad spectrum of resource use allows species to persist in a wide range of habitat types, and thus permits them to occupy large geographical areas, and because broadly distributed species have access to more diverse resource bases, the resource breadth hypothesis posits that the diversity of resources used by organisms should be positively related with the extent of their geographic ranges.We investigated isotopic niche width in a small radiation of South American birds in the genus Cinclodes. We analysed feathers of 12 species of Cinclodes to test the isotopic version of the resource breadth hypothesis and to examine the correlation between isotopic niche breadth and morphology.We found a positive correlation between the widths of hydrogen and oxygen isotopic niches (which estimate breadth of elevational range) and widths of the carbon and nitrogen isotopic niches (which estimates the diversity of resources consumed, and hence of habitats used). We also found a positive correlation between broad isotopic niches and wing morphology.Our study not only supports the resource breadth hypothesis but it also highlights the usefulness of stable isotope analyses as tools in the exploration of ecological niches. It is an example of a macroecological application of stable isotopes. It also illustrates the importance of scientific collections in ecological studies.

Absorption line studies of reflection from horizontally inhomogeneous layers. [in cloudy planetary atmospheres

NASA Technical Reports Server (NTRS)

Appleby, J. F.; Van Blerkom, D. J.

1975-01-01

The article details an inhomogeneous reflecting layer (IRFL) model designed to survey absorption line behavior from a Squires-like cloud cover (which is characterized by convection cell structure). Computational problems and procedures are discussed in detail. The results show trends usually opposite to those predicted by a simple reflecting layer model. Per cent equivalent width variations for the tower model are usually somewhat greater for weak than for relatively strong absorption lines, with differences of a factor of about two or three. IRFL equivalent width variations do not differ drastically as a function of geometry when the total volume of absorbing gas is held constant. The IRFL results are in many instances consistent with observed equivalent width variations of Jupiter, Saturn, and Venus.

Narrow line width dual wavelength semiconductor optical amplifier based random fiber laser

NASA Astrophysics Data System (ADS)

Shawki, Heba A.; Kotb, Hussein E.; Khalil, Diaa

2018-02-01

A novel narrow line-width Single longitudinal mode (SLM) dual wavelength random fiber laser of 20 nm separation between wavelengths of 1530 and 1550 nm is presented. The laser is based on Rayleigh backscattering in a standard single mode fiber of 2 Km length as distributed mirrors, and a semiconductor optical amplifier (SOA) as the optical amplification medium. Two optical bandpass filters are used for the two wavelengths selectivity, and two Faraday Rotator mirrors are used to stabilize the two lasing wavelengths against fiber random birefringence. The optical signal to noise ratio (OSNR) was measured to be 38 dB. The line-width of the laser was measured to be 13.3 and 14 KHz at 1530 and 1550 nm respectively, at SOA pump current of 370 mA.

Theoretical and experimental determination of L -shell decay rates, line widths, and fluorescence yields in Ge

NASA Astrophysics Data System (ADS)

Guerra, M.; Sampaio, J. M.; Madeira, T. I.; Parente, F.; Indelicato, P.; Marques, J. P.; Santos, J. P.; Hoszowska, J.; Dousse, J.-Cl.; Loperetti, L.; Zeeshan, F.; Müller, M.; Unterumsberger, R.; Beckhoff, B.

2015-08-01

Fluorescence yields (FYs) for the Ge L shell were determined by a theoretical and two experimental groups within the framework of the International Initiative on X-Ray Fundamental Parameters Collaboration. Calculations were performed using the Dirac-Fock method, including relativistic and QED corrections. The experimental value of the L3FY ωL 3 was determined at the Physikalisch-Technische Bundesanstalt undulator beamline of the synchrotron radiation facility BESSY II in Berlin, Germany, and the L α1 ,2 and L β1 line widths were measured at the Swiss Light Source, Paul Scherrer Institute, Switzerland, using monochromatized synchrotron radiation and a von Hamos x-ray crystal spectrometer. The measured fluorescence yields and line widths are compared to the corresponding calculated values.

Time-resolved spectrophotometry of the AM Herculis system E2003 + 225

NASA Technical Reports Server (NTRS)

Mccarthy, Patrick; Bowyer, Stuart; Clarke, John T.

1986-01-01

Time-resolved, medium-resolution photometry is reported for the binary system E2003 + 225 over a complete orbital period in 1984. The object was 1.5-2 mag fainter than when viewed earlier in 1984. The fluxes, equivalent widths and full widths at FWHM for dominant lines are presented for four points in the cycle. A coincidence of emission lines and a 4860 A continuum line was observed for the faster component, which had a 500 km/sec velocity amplitude that was symmetric around the zero line. An aberrant emission line component, i.e., stationary narrow emission lines displaced about 9 A from the rest wavelengths, is modeled as Zeeman splitting of emission from material close to the primary.

The 3 micron spectrum of the classical Be star Beta Monocerotis A

NASA Technical Reports Server (NTRS)

Sellgren, K.; Smith, R. G.

1992-01-01

A 3.1-3.7-micron spectrum of the classical Be star Beta Mon A is presented at a resolution of lambda/Delta-lambda of 700-800. The spectrum shows strong hydrogen recombination lines, including Pf-delta and a series of Humphreys lines from Hu 19 to Hu 28. The relative recombination line strengths suggest that Pf-delta has a large optical depth. The Humphreys lines have relative strengths consistent with case B and may be optically thin. The line widths observed are broader than the Balmer lines and similar in width to Fe II lines, consistent with a disk model in which optically thinner lines arise primarily from a faster rotating inner disk, while optically thicker lines come mainly from a slower rotating outer disk. The apparent lack of Stark broadening of the Humphreys lines is used to place an upper limit on the circumstellar electron density of about 10 exp 12/cu cm.

Consequences of a chromospheric temperature gradient on the width of H Alpha in late-type giants

NASA Technical Reports Server (NTRS)

Zarro, D. M.

1984-01-01

An analytic expression for the integrated H alpha optical depth profile is derived for a one dimensional slab geometry model chromosphere, with electron temperature increasing as a power law with height. The formula predicts H alpha opacity and profile width to be sensitive functions of the thermal gradient. Application of the model to observation reveals that broad H alpha absorption widths in G and K giant stars are consistent with a mean H alpha chromospheric optical depth of 50, while narrower widths in M stars indicate slightly lower opacities. It is proposed that differences in H alpha width between late-type giants of similar spectral type may be due, in part, to differences in their chromospheric thermal gradient, and associated H alpha opacity.

Automated Defect and Correlation Length Analysis of Block Copolymer Thin Film Nanopatterns

PubMed Central

Murphy, Jeffrey N.; Harris, Kenneth D.; Buriak, Jillian M.

2015-01-01

Line patterns produced by lamellae- and cylinder-forming block copolymer (BCP) thin films are of widespread interest for their potential to enable nanoscale patterning over large areas. In order for such patterning methods to effectively integrate with current technologies, the resulting patterns need to have low defect densities, and be produced in a short timescale. To understand whether a given polymer or annealing method might potentially meet such challenges, it is necessary to examine the evolution of defects. Unfortunately, few tools are readily available to researchers, particularly those engaged in the synthesis and design of new polymeric systems with the potential for patterning, to measure defects in such line patterns. To this end, we present an image analysis tool, which we have developed and made available, to measure the characteristics of such patterns in an automated fashion. Additionally we apply the tool to six cylinder-forming polystyrene-block-poly(2-vinylpyridine) polymers thermally annealed to explore the relationship between the size of each polymer and measured characteristics including line period, line-width, defect density, line-edge roughness (LER), line-width roughness (LWR), and correlation length. Finally, we explore the line-edge roughness, line-width roughness, defect density, and correlation length as a function of the image area sampled to determine each in a more rigorous fashion. PMID:26207990

Internal kinematics of disk galaxies in the local universe

NASA Astrophysics Data System (ADS)

Catinella, Barbara

2005-11-01

This dissertation makes use of a homogeneous sample of several thousand normal, non-interacting, spiral galaxies, for which I-band photometry and optical and/ or radio spectroscopy are available, to investigate the average kinematic properties of disk systems at low redshifts ( z [Special characters omitted.] 0.1). New long-slit Ha rotation curves (RCs) for 402 galaxies, which were incorporated into the larger sample, are presented in this work. The main goals of this thesis are: (a) The definition of a set of average, or template , RCs in bins covering a wide range of galaxy luminosity. The template relations represent an accurate description of the average circular velocity field of local spiral galaxies, and are intended to be a standard reference for more distant samples and to constrain theoretical models of galactic disks. (b) The characterization of the systematics associated with different velocity width measurement techniques, and the derivation of a robust measure of rotational velocity to be used for applications of the Tully-Fisher (TF) distance method. A direct cross-calibration of the optical and radio widths has been obtained. (c) The assessment of the impact of the limitations on optical line widths extracted from fixed apertures, such as those being collected for ~10 6 galaxies by the on-going Sloan Digital Sky Survey (SDSS). Since the SDSS fiber technique generally does not sample the full extent of a galaxy RC, the observed line widths yield rotational width measurements that depend on the redshifts of the objects, on the physical sizes of their line-emitting regions, and on the intrinsic shapes of their RCs. Numerical simulations of these biases have been carried out for galaxies with realistic circular velocity fields (described by the template RCs) in the redshift range covered by the SDSS spectroscopic sample. Statistical corrections to be applied to the aperture line widths as a function of galaxy redshift and luminosity have been derived, and their impact on the TF relation examined. The use of the SDSS line widths, corrected for aperture effects, has the potential to solve the debated issue of luminosity evolution of galaxies at intermediate redshifts.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guerras, E.; Mediavilla, E.; Jimenez-Vicente, J.

2013-02-20

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

Hot Gas Flows in T Tauri Stars

NASA Astrophysics Data System (ADS)

Ardila, David R.; Herczeg, G.; Gregory, S. G.; Ingleby, L.; France, K.; Brown, A.; Edwards, S.; Linsky, J.; Yang, H.; Valenti, J. A.; Johns-Krull, C. M.; Alexander, R.; Bergin, E. A.; Bethell, T.; Brown, J.; Calvet, N.; Espaillat, C.; Hervé, A.; Hillenbrand, L.; Hussain, G.; Roueff, E.; Schindhelm, E.; Walter, F. M.

2013-01-01

We describe observations of the hot gas 1e5 K) ultraviolet lines C IV and He II, in Classical and Weak T Tauri Stars (CTTSs, WTTSs). Our goal is to provide observational constraints for realistic models. Most of the data for this work comes from the Hubble proposal “The Disks, Accretion, and Outflows (DAO) of T Tau stars” (PI Herczeg). The DAO program is the largest and most sensitive high resolution spectroscopic survey of young stars in the UV ever undertaken and it provides a rich source of information for these objects. The sample of high resolution COS and STIS spectra presented here comprises 35 stars: one Herbig Ae star, 28 CTTSs, and 6 WTTSs. For CTTSs, the lines consist of two kinematic components. The relative strengths of the narrow and broad components (NC, BC) are similar in C IV but in He II the NC is stronger than the BC, and dominates the line profile. We do not find correlations between disk inclination and the velocity centroid, width, or shape of the CIV line profile. The NC of the C IV line in CTTSs increases in strength with accretion rate, and its contribution to the line increases from ˜20% to ˜80%, for the accretion rates considered here (1e-10 to 1e-7 Msun/yr). The CTTSs C IV lines are redshifted by ˜20 km/s while the CTTSs He II are redshifted by ˜10 km/s. Because the He II line and the C IV NC have the same width in CTTSs and in WTTSs, but are correlated with accretion, we suggest that they are produced in the stellar transition region. The accretion shock model predicts that the velocity of the post-shock emission should be 4x smaller than the velocity of the pre-shock emission. Identifying the post-shock emission with the NC and the pre-shock with the BC, we find that this is approximately the case in 11 out of 23 objects. The model cannot explain 11 systems in which the velocity of the NC is smaller than the velocity of the BC, or systems in which one of the velocities is negative (five CTTSs). The hot gas lines in some systems such as HN Tau, RW Aur A, AK Sco, DK Tau, T Tau N, and V1190 Sco require an outflow contribution, which may come from jet shocks in the observed outflows. We suggest that a hot wind is being launched by the Herbig Ae star DX Cha.

Photoionization Modelling of the Giant Broad-Line Region in NGC 3998.

NASA Astrophysics Data System (ADS)

Devereux, Nicholas

2018-01-01

Prior high angular resolution spectroscopic observations of the low-ionization nuclear emission-line region in NGC 3998 obtained with the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope revealed a rich UV-visible spectrum consisting of broad permitted and broad forbidden emission lines. The photoionization code XSTAR is employed together with reddening-insensitive emission line diagnostics to constrain a dynamical model for the broad-line region (BLR) in NGC 3998. The BLR is modelled as a large H+ region ~ 7 pc in radius consisting of dust-free, low density ~ 104 cm-3, low metallicity ~ 0.01 Z/Z⊙ gas. Modelling the shape of the broad Hα emission line significantly discriminates between two independent measures of the black hole mass, favouring the estimate of de Francesco (2006). Interpreting the broad Hα emission line in terms of a steady-state spherically symmetric inflow leads to a mass inflow rate of 1.4 x 10-2 M⊙/yr, well within the present uncertainty of calculations that attempt to explain the observed X-ray emission in terms of an advection-dominated accretion flow (ADAF). Collectively, the model provides an explanation for the shape of the Hα emission line, the relative intensities and luminosities for the H Balmer, [OIII], and potentially several of the broad UV emission lines, as well as refining the initial conditions needed for future modelling of the ADAF.

Search for gravitational redshifted absorption lines in LMXB Serpens X-1

NASA Astrophysics Data System (ADS)

Yoneda, Hiroki; Done, Chris; Paerels, Frits; Takahashi, Tadayuki; Watanabe, Shin

2018-04-01

The equation of state for ultradense matter can be tested from observations of the ratio of mass to radius of neutron stars. This could be measured precisely from the redshift of a narrow line produced on the surface. X-rays bursts have been intensively searched for such features, but so far without detection. Here instead we search for redshifted lines in the persistent emission, where the accretion flow dominates over the surface emission. We discuss the requirements for narrow lines to be produced, and show that narrow absorption lines from highly ionized iron can potentially be observable in accreting low-mass X-ray binaries (LMXBs; low B field) that have either low spin or low inclination so that Doppler broadening is small. This selects Serpens X-1 as the only potential candidate persistent LMXB due to its low inclination. Including surface models in the broad-band accretion flow model predicts that the absorption line from He-like iron at 6.7 keV should be redshifted to ˜5.1-5.7 keV (10-15 km for 1.4 M⊙) and have an equivalent width of 0.8-8 eV for surface temperatures of 7-10 × 106 K. We use the high-resolution Chandra grating data to give a firm upper limit of 2-3 eV for an absorption line at ˜5 keV. We discuss possible reasons for this lack of detection (the surface temperature and the geometry of the boundary layer etc.). Future instruments with better sensitivity are required in order to explore the existence of such features.

BeppoSAX Observations of MKN 110

NASA Technical Reports Server (NTRS)

Nicastro, Fabrizio; Oliversen, Ronald J. (Technical Monitor)

2002-01-01

Mkn 110 is a bright, nearby Seyfert 1 galaxy, which underwent a long optical monitoring campaign, during the past 12 years. Optical observations show that Mkn 110 vary, both in flux and spectral shape. The intensity and width of its Broad Emission Lines (BELs) also vary, from typical Seyfert 1, to typical Narrow Line Seyfert 1 (NLSyl) values, so suggesting that this could be the first supermassive black holes where accretion state related transitions, as frequently observed in stellar-size black holes, have finally been observed. To verify these suggestions we asked to monitor Mkn 110 with BeppoSAX with three 50 ksec observations six months apart. The goal of the proposal was to observe spectral variations in X-ray, already suggested by previous, existing ROSAT (Roentgen Satellite) and ASCA (Advanced Satellite for Cosmology and Astrophysics) observations of the same source. The first of these three SAX (Satellite per Astronomia X) observations was taken on May 2000, and lacks the Low-Energy instrument (0.1-2 keV is the band in which NLSy1 and Sy1 X-ray spectra differ most).

A compact 7-cell Si-drift detector module for high-count rate X-ray spectroscopy.

PubMed

Hansen, K; Reckleben, C; Diehl, I; Klär, H

2008-05-01

A new Si-drift detector module for fast X-ray spectroscopy experiments was developed and realized. The Peltier-cooled module comprises a sensor with 7 × 7-mm 2 active area, an integrated circuit for amplification, shaping and detection, storage, and derandomized readout of signal pulses in parallel, and amplifiers for line driving. The compactness and hexagonal shape of the module with a wrench size of 16mm allow very short distances to the specimen and multi-module arrangements. The power dissipation is 186mW. At a shaper peaking time of 190 ns and an integration time of 450 ns an electronic rms noise of ~11 electrons was achieved. When operated at 7 °C, FWHM line widths around 260 and 460 eV (Cu-K α ) were obtained at low rates and at sum-count rates of 1.7 MHz, respectively. The peak shift is below 1% for a broad range of count rates. At 1.7-MHz sum-count rate the throughput loss amounts to 30%.

Measurements of air-broadened and nitrogen-broadened half-widths and shifts of ozone lines near 9 microns

NASA Technical Reports Server (NTRS)

Smith, M. A. H.; Rinsland, C. P.; Devi, Malathy V.; Benner, D. Chris; Thakur, K. B.

1988-01-01

Air- and nitrogen-broadened half-widths and line shifts at room temperature for more than 60 individual vibration-rotation transitions in the nu1 fundamental band of (O-16)3 and several transitions in the nu3 band were determined from infrared absorption spectra. These spectra were recorded at 0.005/cm resolution with a Fourier-transform spectrometer. A tunable-diode-laser spectrometer operating in the 1090-1150/cm region was also used to record data on oxygen-, nitrogen-, and air-broadened half-widths for selected individual transitions. The nitrogen- and air-broadened half-widths determined by these two different measurement techniques are consistent to within 4 percent. The results are in good agreement with other published measurements and calculations.

25 CFR 169.26 - Telephone and telegraph lines; radio, television, and other communications facilities.

Code of Federal Regulations, 2010 CFR

2010-04-01

... width in excess of 50 feet on each side of the centerline, unless special requirements are clearly set forth in the application which fully justify a width in excess of 50 feet on each side of the centerline... from those showing the line of route, and shall be drawn to a scale of 50 feet to an inch. Such maps...

25 CFR 169.26 - Telephone and telegraph lines; radio, television, and other communications facilities.

Code of Federal Regulations, 2011 CFR

2011-04-01

... width in excess of 50 feet on each side of the centerline, unless special requirements are clearly set forth in the application which fully justify a width in excess of 50 feet on each side of the centerline... from those showing the line of route, and shall be drawn to a scale of 50 feet to an inch. Such maps...

INTERNATIONAL CONFERENCE ON SEMICONDUCTOR INJECTION LASERS SELCO-87: Line width of a single longitudinal mode emitted by an AlGaAs heterojunction laser

NASA Astrophysics Data System (ADS)

Bogatov, Alexandr P.; Eliseev, P. G.; Luk'yanov, S. A.; Pak, G. T.; Petrakova, T. V.

1988-11-01

A nonmonotonic dependence of the emission line width on the power was observed for a single longitudinal mode of an AlGaAs heterojunction laser. This behavior could be due to the dependence of the waveguide coefficient of the amplitude-phase coupling on the nature of operation of the laser.

EISCAT and ESRAD radars observations of polar mesosphere winter echoes during solar proton events on 11-12 November 2004

NASA Astrophysics Data System (ADS)

Belova, E.; Kirkwood, S.; Sergienko, T.

2013-07-01

Polar mesosphere winter echoes (PMWE) were detected by two radars, ESRAD at 52 MHz located near Kiruna, Sweden, and EISCAT at 224 MHz located near Tromsø, Norway, during the strong solar proton event on 11-12 November 2004. PMWE maximum volume reflectivity was estimated to be 3 × 10-15 m-1 for ESRAD and 2 × 10-18 m-1 for EISCAT. It was found that the shape of the echo power spectrum is close to Gaussian inside the PMWE layers, and outside of them it is close to Lorentzian, as for the standard ion line of incoherent scatter (IS). The EISCAT PMWE spectral width is about 5-7 m s-1 at 64-67 km and 7-10 m s-1 at 68-70 km. At the lower altitudes the PMWE spectral widths are close to those for the IS ion line derived from the EISCAT data outside the layers. At the higher altitudes the PMWE spectra are broader by 2-4 m s-1 than those for the ion line. The ESRAD PMWE spectral widths at 67-72 km altitude are 3-5 m s-1, that is, 2-4 m s-1 larger than ion line spectral widths modelled for the ESRAD radar. The PMWE spectral widths for both EISCAT and ESRAD showed no dependence on the echo strength. It was found that all these facts cannot be explained by turbulent origin of the echoes. We suggested that evanescent perturbations in the electron gas generated by the incident infrasound waves may explain the observed PMWE spectral widths. However, a complete theory of radar scatter from this kind of disturbance needs to be developed before a full conclusion can be made.

Stellar Photometric Structures of the Host Galaxies of Nearby Type 1 Active Galactic Nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Minjin; Ho, Luis C.; Peng, Chien Y.

2017-10-01

We present detailed image analysis of rest-frame optical images of 235 low-redshift ( z ≲ 0.35) Type 1 active galactic nuclei (AGNs) observed with the Hubble Space Telescope . The high-resolution images enable us to perform rigorous two-dimensional image modeling to decouple the luminous central point source from the host galaxy, which, when warranted, is further decomposed into its principal structural components (bulge, bar, and disk). In many cases, care must be taken to account for structural complexities such as spiral arms, tidal features, and overlapping or interacting companion galaxies. We employ Fourier modes to characterize the degree of asymmetrymore » of the light distribution of the stars as a quantitative measure of morphological distortion due to interactions or mergers. We examine the dependence of the physical parameters of the host galaxies on the properties of the AGNs, namely, radio-loudness and the width of the broad emission lines. In accordance with previous studies, narrow-line (H β FWHM ≤ 2000 km s{sup −1}) Type 1 AGNs, in contrast to their broad-line (H β FWHM > 2000 km s{sup −1}) counterparts, are preferentially hosted in later-type, lower-luminosity galaxies, which have a higher incidence of pseudo-bulges, are more frequently barred, and are less morphologically disturbed. This suggests that narrow-line Type 1 AGNs experienced a more quiescent evolutionary history driven primarily by internal secular evolution instead of external dynamical perturbations. The fraction of AGN hosts showing merger signatures is larger for more luminous sources. Radio-loud AGNs generally preferentially live in earlier-type (bulge-dominated), more massive hosts, although a minority of them appear to contain a significant disk component. We do not find convincing evidence for enhanced merger signatures in the radio-loud population.« less

The development of a tunable, single-frequency ultraviolet laser source for UV filtered Rayleigh scattering

NASA Technical Reports Server (NTRS)

Finkelstein, N.; Gambogi, J.; Lempert, Walter R.; Miles, Richard B.; Rines, G. A.; Finch, A.; Schwarz, R. A.

1995-01-01

We present the development of a flexible, high power, narrow line width, tunable ultraviolet source for diagnostic application. By frequency tripling the output of a pulsed titanium-sapphire laser, we achieve broadly tunable (227-360 nm) ultraviolet light with high quality spatial and spectral resolution. We also present the characterization of a mercury vapor cell which provides a narrow band, sharp edge absorption filter at 253.7 nm. These two components form the basis for the extension of the Filtered Rayleigh Scattering technique into the ultraviolet. The UV-FRS system is comprised of four pieces: a single frequency, cw tunable Ti:Sapphire seeding source; a high-powered pulsed Ti:Sapphire oscillator; a third harmonic generator system; and an atomic mercury vapor filter. In this paper we discuss the development and characterization of each of these elements.

Measurements of argon-, helium-, hydrogen-, and nitrogen-broadened widths of methane lines near 9000 per cm

NASA Technical Reports Server (NTRS)

Fox, Kenneth; Jennings, Donald E.; Stern, Elizabeth A.; Hubbard, Rob

1988-01-01

Pressure-broadened widths of rotational-vibrational lines in CH4 have been measured at very high spectral resolution in the R-branch of the 3nu3 overtone. The broadening gases were Ar, He, H2, and N2. Results are presented as averages for J-multiplets at ambient temperature. The overall values (per cm per atm) for these R-branch lines are 0.0651 (CH4-Ar), 0.0508 (CH4-He), 0.0728 (CH4-H2), and 0.0715 (CH4-N2).

The Sloan Digital Sky Survey Reverberation Mapping Project: The C IV Blueshift, Its Variability, and Its Dependence Upon Quasar Properties

NASA Astrophysics Data System (ADS)

Sun, Mouyuan; Xue, Yongquan; Richards, Gordon T.; Trump, Jonathan R.; Shen, Yue; Brandt, W. N.; Schneider, D. P.

2018-02-01

We use the multi-epoch spectra of 362 quasars from the Sloan Digital Sky Survey Reverberation Mapping project to investigate the dependence of the blueshift of C IV relative to Mg II on quasar properties. We confirm that high-blueshift sources tend to have low C IV equivalent widths (EWs), and that the low-EW sources span a range of blueshift. Other high-ionization lines, such as He II, also show similar blueshift properties. The ratio of the line width (measured as both the full width at half maximum and the velocity dispersion) of C IV to that of Mg II increases with blueshift. Quasar variability enhances the connection between the C IV blueshift and quasar properties (e.g., EW). The variability of the Mg II line center (i.e., the wavelength that bisects the cumulative line flux) increases with blueshift. In contrast, the C IV line center shows weaker variability at the extreme blueshifts. Quasars with the high-blueshift C IV lines tend to have less variable continuum emission, when controlling for EW, luminosity, and redshift. Our results support the scenario that high-blueshift sources tend to have large Eddington ratios.

Experimental and theoretical investigation of the rocking curves measured for MoK{sub α} X-ray characteristic lines in the double-crystal nondispersive scheme

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marchenkov, N. V., E-mail: marchenkov@ns.crys.ras.ru; Chukhovskii, F. N.; Blagov, A. E.

2015-03-15

The rocking curves (RCs) for MoK{sub α1} and MoK{sub α2} characteristic X-ray lines have been experimentally and theoretically studied in the nondispersive scheme of an X-ray double-crystal TPC-K diffractometer. The results of measurements and theoretical calculations of double-crystal RCs for characteristic X-rays from tubes with a molybdenum anode and different widths of slits show that a decrease in the slit width leads to an increase in the relative contribution of the MoK{sub α2}-line RC in comparison with the intensity of the tails of the MoK{sub α1}-line RC. It is shown that the second peak of the MoK{sub α2} line becomesmore » increasingly pronounced in the tail of the MoK{sub α1}-line RC with a decrease in the slit width. Two plane-parallel Si plates (input faces (110), diffraction vector h 〈220〉) were used as a monochromator crystal and a sample. The results of measuring double-crystal RCs are in good agreement with theoretical calculations.« less

Raman Spectra of Crystalline Double Calcium Orthovanadates Ca10M(VO4)7 (M = Li, K, Na) and Their Interpretation Based on Deconvolution Into Voigt Profiles

NASA Astrophysics Data System (ADS)

Khodasevich, I. A.; Voitikov, S. V.; Orlovich, V. A.; Kosmyna, M. B.; Shekhovtsov, A. N.

2016-09-01

Unpolarized spontaneous Raman spectra of crystalline double calcium orthovanadates Ca10M(VO4)7 (M = Li, K, Na) in the range 150-1600 cm-1 were measured. Two vibrational bands with full-width at half-maximum (FWHM) of 37-50 cm-1 were found in the regions 150-500 and 700-1000 cm-1. The band shapes were approximated well by deconvolution into Voigt profiles. The band at 700-1000 cm-1 was stronger and deconvoluted into eight Voigt profiles. The frequencies of two strong lines were ~848 and ~862 cm-1 for Ca10Li(VO4)7; ~850 and ~866 cm-1 for Ca10Na(VO4)7; and ~844 and ~866 cm-1 for Ca10K(VO4)7. The Lorentzian width parameters of these lines in the Voigt profiles were ~5 times greater than those of the Gaussian width parameters. The FWHM of the Voigt profiles were ~18-42 cm-1. The two strongest lines had widths of 21-25 cm-1. The vibrational band at 300-500 cm-1 was ~5-6 times weaker than that at 700-1000 cm-1 and was deconvoluted into four lines with widths of 25-40 cm-1. The large FWHM of the Raman lines indicated that the crystal structures were disordered. These crystals could be of interest for Raman conversion of pico- and femtosecond laser pulses because of the intense vibrations with large FWHM in the Raman spectra.

Effects of interventions on normalizing step width during self-paced dual-belt treadmill walking with virtual reality, a randomised controlled trial.

PubMed

Oude Lansink, I L B; van Kouwenhove, L; Dijkstra, P U; Postema, K; Hijmans, J M

2017-10-01

Step width is increased during dual-belt treadmill walking, in self-paced mode with virtual reality. Generally a familiarization period is thought to be necessary to normalize step width. The aim of this randomised study was to analyze the effects of two interventions on step width, to reduce the familiarization period. We used the GRAIL (Gait Real-time Analysis Interactive Lab), a dual-belt treadmill with virtual reality in the self-paced mode. Thirty healthy young adults were randomly allocated to three groups and asked to walk at their preferred speed for 5min. In the first session, the control-group received no intervention, the 'walk-on-the-line'-group was instructed to walk on a line, projected on the between-belt gap of the treadmill and the feedback-group received feedback about their current step width and were asked to reduce it. Interventions started after 1min and lasted 1min. During the second session, 7-10days later, no interventions were given. Linear mixed modeling showed that interventions did not have an effect on step width after the intervention period in session 1. Initial step width (second 30s) of session 1 was larger than initial step width of session 2. Step width normalized after 2min and variation in step width stabilized after 1min. Interventions do not reduce step width after intervention period. A 2-min familiarization period is sufficient to normalize and stabilize step width, in healthy young adults, regardless of interventions. A standardized intervention to normalize step width is not necessary. Copyright © 2017 Elsevier B.V. All rights reserved.

Detector Sampling of Optical/IR Spectra: How Many Pixels per FWHM?

NASA Astrophysics Data System (ADS)

Robertson, J. Gordon

2017-08-01

Most optical and IR spectra are now acquired using detectors with finite-width pixels in a square array. Each pixel records the received intensity integrated over its own area, and pixels are separated by the array pitch. This paper examines the effects of such pixellation, using computed simulations to illustrate the effects which most concern the astronomer end-user. It is shown that coarse sampling increases the random noise errors in wavelength by typically 10-20 % at 2 pixels per Full Width at Half Maximum, but with wide variation depending on the functional form of the instrumental Line Spread Function (i.e. the instrumental response to a monochromatic input) and on the pixel phase. If line widths are determined, they are even more strongly affected at low sampling frequencies. However, the noise in fitted peak amplitudes is minimally affected by pixellation, with increases less than about 5%. Pixellation has a substantial but complex effect on the ability to see a relative minimum between two closely spaced peaks (or relative maximum between two absorption lines). The consistent scale of resolving power presented by Robertson to overcome the inadequacy of the Full Width at Half Maximum as a resolution measure is here extended to cover pixellated spectra. The systematic bias errors in wavelength introduced by pixellation, independent of signal/noise ratio, are examined. While they may be negligible for smooth well-sampled symmetric Line Spread Functions, they are very sensitive to asymmetry and high spatial frequency sub-structure. The Modulation Transfer Function for sampled data is shown to give a useful indication of the extent of improperly sampled signal in an Line Spread Function. The common maxim that 2 pixels per Full Width at Half Maximum is the Nyquist limit is incorrect and most Line Spread Functions will exhibit some aliasing at this sample frequency. While 2 pixels per Full Width at Half Maximum is nevertheless often an acceptable minimum for moderate signal/noise work, it is preferable to carry out simulations for any actual or proposed Line Spread Function to find the effects of various sampling frequencies. Where spectrograph end-users have a choice of sampling frequencies, through on-chip binning and/or spectrograph configurations, it is desirable that the instrument user manual should include an examination of the effects of the various choices.

A new mathematical formulation of the line-by-line method in case of weak line overlapping

NASA Technical Reports Server (NTRS)

Ishov, Alexander G.; Krymova, Natalie V.

1994-01-01

A rigorous mathematical proof is presented for multiline representation on the equivalent width of a molecular band which consists in the general case of n overlapping spectral lines. The multiline representation includes a principal term and terms of minor significance. The principal term is the equivalent width of the molecular band consisting of the same n nonoverlapping spectral lines. The terms of minor significance take into consideration the overlapping of two, three and more spectral lines. They are small in case of the weak overlapping of spectral lines in the molecular band. The multiline representation can be easily generalized for optically inhomogeneous gas media and holds true for combinations of molecular bands. If the band lines overlap weakly the standard formulation of line-by-line method becomes too labor-consuming. In this case the multiline representation permits line-by-line calculations to be performed more effectively. Other useful properties of the multiline representation are pointed out.

The nova-like cataclysmic variable star: KUV 0859+415

NASA Astrophysics Data System (ADS)

Grauer, Albert D.; Ringwald, F. A.; Wegner, Gary; Liebert, James; Schmidt, Gary D.; Green, Richard F.

1994-07-01

KUV 0859+415 has been found to be an eclipsing, nova-like cataclysmic variable with an orbital period of 3 h and 40 min. We find that it differs from other eclipsing systems of similar period (sometimes called the SW Sex stars) in several important respects. First, the eclipses are shallow, V-shaped dips, suggesting that the inclination angle is relatively low. Also, while the excitation of the emission lines are relatively high (He II comparable to H-beta), they are relatively weak compared to the continuum. The high Balmer lines have broad absorption wings, characteristic of an optically thick accretion disk. Yet there is evidence for a 'hot spot' in the system, which reaches peak brightness near phase 0.9 before the eclipse. Perhaps the most puzzling property of this system is that the H-alpha emission line radial velocity leads rather than lags the expected position for the location of the accretion disk. We present briefly a phenomenological model for the system which has a hot spot located at the normal location for the accretion stream to first impact the disk and is the source of excess optical continuum. However, the velocity curve of the emission lines requires us to conclude that the bulk of this radiation forms on the opposite side of the disk. This also explains the fact that the peak equivalent widths of H-alpha occur at phases 0.4-0.5.

A Census of X-Ray Gas in NGC 1068: Results from 450ks of Chandra HETG Observations

NASA Technical Reports Server (NTRS)

Kallman, T.; Evans, Daniel A.; Marshall, H.; Canizares, C.; Longinotti, A.; Nowak, M.; Schulz, N.

2013-01-01

We present models for the X-ray spectrum of the Seyfert 2 galaxy NGC 1068. These are fitted to data obtained using the High Energy Transmission Grating (HETG) on the Chandra X-ray observatory. The data show line and radiative recombination continuum (RRC) emission from a broad range of ions and elements. The models explore the importance of excitation processes for these lines including photoionization followed by recombination, radiative excitation by absorption of continuum radiation and inner shell fluorescence. The models show that the relative importance of these processes depends on the conditions in the emitting gas, and that no single emitting component can fit the entire spectrum. In particular, the relative importance of radiative excitation and photoionization/recombination differs according to the element and ion stage emitting the line. This in turn implies a diversity of values for the ionization parameter of the various components of gas responsible for the emission, ranging from log(Epsilon)=1 - 3. Using this, we obtain an estimate for the total amount of gas responsible for the observed emission. The mass flux through the region included in the HETG extraction region is approximately 0.3 Solar Mass/yr assuming ordered flow at the speed characterizing the line widths. This can be compared with what is known about this object from other techniques.

A Census of X-ray Gas in NGC 1068: Results From 450 ks of CHANDRA High Energy Transmisson Grating Observations

NASA Technical Reports Server (NTRS)

Kallman, T.; Evans, Daniel A.; Marshall, H.; Canizares, C.; Longinotti, A.; Nowak, M.; Schulz, N.

2013-01-01

We present models for the X-ray spectrum of the Seyfert 2 galaxy NGC 1068. These are fitted to data obtained using the High Energy Transmission Grating on Chandra. The data show line and radiative recombination continuum emission from a broad range of ions and elements. The models explore the importance of excitation processes for these lines including photoionization followed by recombination, radiative excitation by absorption of continuum radiation, and inner shell fluorescence. The models show that the relative importance of these processes depends on the conditions in the emitting gas and that no single emitting component can fit the entire spectrum. In particular, the relative importance of radiative excitation and photoionization/recombination differs according to the element and ion stage emitting the line. This in turn implies a diversity of values for the ionization parameter of the various components of gas responsible for the emission, ranging from log(E ) = 1 to 3. Using this, we obtain an estimate for the total amount of gas responsible for the observed emission. The mass flux through the region included in the HETG extraction region is approximately 0.3M/yr, assuming ordered flow at the speed characterizing the line widths. This can be compared with what is known about this object from other techniques.

A Census of X-ray gas in NGC 1068: Results from 450ks of Chandra HETG Observations.

PubMed

Kallman, T; Evans, Daniel A; Marshall, H; Canizares, C; Longinotti, A; Nowak, M; Schulz, N

2014-01-10

We present models for the X-ray spectrum of the Seyfert 2 galaxy NGC 1068. These are fitted to data obtained using the High Energy Transmission Grating (HETG) on the Chandra X-ray observatory. The data show line and radiative recombination continuum (RRC) emission from a broad range of ions and elements. The models explore the importance of excitation processes for these lines including photoionization followed by recombination, radiative excitation by absorption of continuum radiation and inner shell fluorescence. The models show that the relative importance of these processes depends on the conditions in the emitting gas, and that no single emitting component can fit the entire spectrum. In particular, the relative importance of radiative excitation and photoionization/recombination differs according to the element and ion stage emitting the line. This in turn implies a diversity of values for the ionization parameter of the various components of gas responsible for the emission, ranging from log(ξ)=1 - 3. Using this, we obtain an estimate for the total amount of gas responsible for the observed emission. The mass flux through the region included in the HETG extraction region is approximately 0.3 M ⊙ yr -1 assuming ordered flow at the speed characterizing the line widths. This can be compared with what is known about this object from other techniques.

A wave-mechanical model of incoherent quasielastic scattering in complex systems.

PubMed

Frauenfelder, Hans; Fenimore, Paul W; Young, Robert D

2014-09-02

Quasielastic incoherent neutron scattering (QENS) is an important tool for the exploration of the dynamics of complex systems such as biomolecules, liquids, and glasses. The dynamics is reflected in the energy spectra of the scattered neutrons. Conventionally these spectra are decomposed into a narrow elastic line and a broad quasielastic band. The band is interpreted as being caused by Doppler broadening due to spatial motion of the target molecules. We propose a quantum-mechanical model in which there is no separate elastic line. The quasielastic band is composed of sharp lines with twice the natural line width, shifted from the center by a random walk of the protein in the free-energy landscape of the target molecule. The walk is driven by vibrations and by external fluctuations. We first explore the model with the Mössbauer effect. In the subsequent application to QENS we treat the incoming neutron as a de Broglie wave packet. While the wave packet passes the protons in the protein and the hydration shell it exchanges energy with the protein during the passage time of about 100 ns. The energy exchange broadens the ensemble spectrum. Because the exchange involves the free-energy landscape of the protein, the QENS not only provides insight into the protein dynamics, but it may also illuminate the free-energy landscape of the protein-solvent system.

Association of Anterior Cruciate Ligament Width With Anterior Knee Laxity.

PubMed

Wang, Hsin-Min; Shultz, Sandra J; Schmitz, Randy J

2016-06-02

Greater anterior knee laxity (AKL) has been identified as an anterior cruciate ligament (ACL) injury risk factor. The structural factors that contribute to greater AKL are not fully understood but may include the ACL and bone geometry. To determine the relationship of ACL width and femoral notch angle to AKL. Cross-sectional study. Controlled laboratory. Twenty recreationally active females (age = 21.2 ± 3.1 years, height = 1.66.1 ± 7.3 cm, mass = 66.5 ± 12.0 kg). Anterior cruciate ligament width and femoral notch angle were obtained with magnetic resonance imaging of the knee and AKL was assessed. Anterior cruciate ligament width was measured as the width of a line that transected the ACL and was drawn perpendicular to the Blumensaat line. Femoral notch angle was formed by the intersection of the line parallel to the posterior cortex of the femur and the Blumensaat line. Anterior knee laxity was the anterior displacement of the tibia relative to the femur (mm) at 130 N of an applied force. Ten participants' magnetic resonance imaging data were assessed on 2 occasions to establish intratester reliability and precision. Using stepwise backward linear regression, we examined the extent to which ACL width, femoral notch angle, and weight were associated with AKL. Strong measurement consistency and precision (intraclass correlation coefficient [2,1] ± SEM) were established for ACL width (0.98 ± 0.3 mm) and femoral notch angle (0.97° ± 1.1°). The regression demonstrated that ACL width (5.9 ± 1.4 mm) was negatively associated with AKL (7.2 ± 2.0 mm; R(2) = 0.22, P = .04). Femoral notch angle and weight were not retained in the final model. A narrower ACL was associated with greater AKL. This finding may inform the development of ACL injury-prevention programs that include components designed to increase ACL size or strength (or both). Future authors should establish which other factors contribute to greater AKL in order to best inform injury-prevention efforts.

Molybdenum electron impact width parameter measurement by laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Sternberg, E. M. A.; Rodrigues, N. A. S.; Amorim, J.

2016-01-01

In this work, we suggest a method for electron impact width parameter calculation based on Stark broadening of emission lines of a laser-ablated plasma plume. First, electron density and temperature must be evaluated by means of the Saha-Boltzmann plot method for neutral and ionized species of the plasma. The method was applied for laser-ablated molybdenum plasma plume. For molybdenum plasma electron temperature, which varies around 10,000 K, and electron density, which reaches values around 1018 cm-3, and considering that total measured line broadening was due experimental and Stark broadening mainly, electron impact width parameter of molybdenum emission lines was determined as (0.01 ± 0.02) nm. Intending to validate the presented method, it was analyzed the laser-ablated aluminum plasma plume and the obtained results were in agreement with the predicted on the literature.

Line width measurement below 60 nm using an optical interferometer and artificial neural network

NASA Astrophysics Data System (ADS)

See, Chung W.; Smith, Richard J.; Somekh, Michael G.; Yacoot, Andrew

2007-03-01

We have recently described a technique for optical line-width measurements. The system currently is capable of measuring line-width down to 60 nm with a precision of 2 nm, and potentially should be able to measure down to 10nm. The system consists of an ultra-stable interferometer and artificial neural networks (ANNs). The former is used to generate optical profiles which are input to the ANNs. The outputs of the ANNs are the desired sample parameters. Different types of samples have been tested with equally impressive results. In this paper we will discuss the factors that are essential to extend the application of the technique. Two of the factors are signal conditioning and sample classification. Methods, including principal component analysis, that are capable of performing these tasks will be considered.

Single steady frequency and narrow-linewidth external-cavity semiconductor laser

NASA Astrophysics Data System (ADS)

Zhao, Weirui; Jiang, Pengfei; Xie, Fuzeng

2003-11-01

A single longitudinal mode and narrow line width external cavity semiconductor laser is proposed. It is constructed with a semiconductor laser, collimator, a flame grating, and current and temperature control systems. The one facet of semiconductor laser is covered by high transmission film, and another is covered by high reflection film. The flame grating is used as light feedback element to select the mode of the semiconductor laser. The temperature of the constructed external cavity semiconductor laser is stabilized in order of 10-3°C by temperature control system. The experiments have been carried out and the results obtained - the spectral line width of this laser is compressed to be less than 1.4MHz from its original line-width of more than 1200GHz and the output stability (including power and mode) is remarkably enhanced.

Common angle plots as perception-true visualizations of categorical associations.

PubMed

Hofmann, Heike; Vendettuoli, Marie

2013-12-01

Visualizations are great tools of communications-they summarize findings and quickly convey main messages to our audience. As designers of charts we have to make sure that information is shown with a minimum of distortion. We have to also consider illusions and other perceptual limitations of our audience. In this paper we discuss the effect and strength of the line width illusion, a Muller-Lyer type illusion, on designs related to displaying associations between categorical variables. Parallel sets and hammock plots are both affected by line width illusions. We introduce the common-angle plot as an alternative method for displaying categorical data in a manner that minimizes the effect from perceptual illusions. Results from user studies both highlight the need for addressing line-width illusions in displays and provide evidence that common angle charts successfully resolve this issue.

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

NASA Technical Reports Server (NTRS)

Kallman, T.; Mushotzky, R.

1985-01-01

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

Scanning electron microscope measurement of width and shape of 10nm patterned lines using a JMONSEL-modeled library.

PubMed

Villarrubia, J S; Vladár, A E; Ming, B; Kline, R J; Sunday, D F; Chawla, J S; List, S

2015-07-01

The width and shape of 10nm to 12 nm wide lithographically patterned SiO2 lines were measured in the scanning electron microscope by fitting the measured intensity vs. position to a physics-based model in which the lines' widths and shapes are parameters. The approximately 32 nm pitch sample was patterned at Intel using a state-of-the-art pitch quartering process. Their narrow widths and asymmetrical shapes are representative of near-future generation transistor gates. These pose a challenge: the narrowness because electrons landing near one edge may scatter out of the other, so that the intensity profile at each edge becomes width-dependent, and the asymmetry because the shape requires more parameters to describe and measure. Modeling was performed by JMONSEL (Java Monte Carlo Simulation of Secondary Electrons), which produces a predicted yield vs. position for a given sample shape and composition. The simulator produces a library of predicted profiles for varying sample geometry. Shape parameter values are adjusted until interpolation of the library with those values best matches the measured image. Profiles thereby determined agreed with those determined by transmission electron microscopy and critical dimension small-angle x-ray scattering to better than 1 nm. Published by Elsevier B.V.

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.;

Photoionization modelling of the giant broad-line region in NGC 3998

NASA Astrophysics Data System (ADS)

Devereux, Nick

2018-01-01

Prior high angular resolution spectroscopic observations of the Low-ionization nuclear emission-line region (Liner) in NGC 3998 obtained with the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope (HST) revealed a rich UV-visible spectrum consisting of broad permitted and broad forbidden emission lines. The photoionization code XSTAR is employed together with reddening-insensitive emission line diagnostics to constrain a dynamical model for the broad-line region (BLR) in NGC 3998. The BLR is modelled as a large H+ region ∼ 7 pc in radius consisting of dust-free, low-density ∼ 104 cm-3, low-metallicity ∼ 0.01 Z/Z⊙ gas. Modelling the shape of the broad H α emission line significantly discriminates between two independent measures of the black hole (BH) mass, favouring the estimate of de Francesco, Capetti & Marconi (2006). Interpreting the broad H α emission line in terms of a steady-state spherically symmetric inflow leads to a mass inflow rate of 1.4 × 10-2 M⊙ yr-1, well within the present uncertainty of calculations that attempt to explain the observed X-ray emission in terms of an advection-dominated accretion flow (ADAF). Collectively, the model provides an explanation for the shape of the H α emission line, the relative intensities and luminosities for the H Balmer, [O III], and potentially several of the broad UV emission lines, as well as refining the initial conditions needed for future modelling of the ADAF.

Stark parameter dependence of the rest core charge of the emitters for multiply charged ions spectral lines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Šćepanović, M., E-mail: mara.scepanovic@gmail.com; Purić, J.

2016-03-25

Stark width and shift simultaneous dependence on the upper level ionization potential and rest core charge of the emitter has been evaluated and discussed. It has been verified that the found relations, connecting Stark broadening parameters with upper level ionization potential and rest core charge of the emitters for particular electron temperature and density, can be used for prediction of Stark line width and shift data in case of ions for which observed data, or more detailed calculations, are not yet available. Stark widths and shifts published data are used to demonstrate the existence of other kinds of regularities withinmore » similar spectra of different elements and their ionization stages. The emphasis is on the Stark parameter dependence on the upper level ionization potential and on the rest core charge for the lines from similar spectra of multiply charged ions. The found relations connecting Stark widths and shift parameters with upper level ionization potential, rest core charge and electron temperature were used for a prediction of new Stark broadening data, thus avoiding much more complicated procedures.« less

Goddard High-Resolution Spectrograph Observations of Procyon and HR1099

NASA Technical Reports Server (NTRS)

Wood, Brian E.; Harper, Graham M.; Linsky, Jeffrey L.; Dempsey, Robert C.

1996-01-01

Goddard High Resolution Spectrograph (GHRS) observations have revealed the presence of broad wings in the transition-region lines of AU Mic and Capella. It has been proposed that these wings are signatures of microflares in the transition regions of these stars and that the solar analog for this phenomenon might be the 'transition region explosive events' discussed by Dere, Bartoe, & Brueckner. We have analyzed GHRS observations of Procyon (F5 IV-V) and HR 1099 (K1 IV + G5 IV) to search for broad wings in the UV emission lines of these stars. We find that the transition-region lines of HR 1099, which are emitted almost entirely by the K1 star, do indeed have broad wings that are even more prominent than those of AU Mic and Capella. This is consistent with the association of the broad wings with microflaring since HR 1099 is a very active binary system. In contrast, the transition-region lines of Procyon, a relatively inactive star, do not show evidence for broad wings, with the possible exception of N v lambda1239. However, Procyon's lines do appear to have excess emission in their blue wings. Linsky et al. found no evidence for broad wings in Capella's chromospheric lines, but we find that the Mg II resonance lines of HR 1099 do have broad wings. The striking resemblance between HR 1099's Mg II and C iv lines suggests that the Mg II line profiles may be regulated by turbulent processes similar to those that control the transition-region line profiles. If this is the case, microflaring may be occurring in the K1 star's chromosphere as well as in its transition region. However, radiative transfer calculations suggest that the broad wings of the Mg II lines can also result from normal chromospheric opacity effects rather than pure turbulence. The prominence of broad wings in the transition region and perhaps even chromospheric lines of active stars suggests that microflaring is very prevalent in the outer atmospheres of active stars.

Visual search performance on an lcd monitor: effects of color combination of figure and icon background, shape of icon, and line width of icon border.

PubMed

Huang, Kuo-Chen; Chiu, Tsai-Lan

2007-04-01

This study investigated the effects of color combinations for the figure/icon background, icon shape, and line width of the icon border on visual search performance on a liquid crystal display screen. In a circular stimulus array, subjects had to search for a target item which had a diameter of 20 cm and included one target and 19 distractors. Analysis showed that the icon shape significantly affected search performance. The correct response time was significantly shorter for circular icons than for triangular icons, for icon borders with a line width of 3 pixels than for 1 or 2 pixels, and for 2 pixels than for 1 pixel. The color combination also significantly affected the visual search performance: white/yellow, white/blue, black-red, and black/ yellow color combinations for the figure/icon background had shorter correct response times compared to yellow/blue, red/green, yellow/green, and blue/red. However, no effects were found for the line width of the icon border or the icon shape on the error rate. Results have implications for graphics-based design of interfaces, such as for mobile phones, Web sites, and PDAs, as well as complex industrial processes.

Variable-Period Undulators For Synchrotron Radiation

DOEpatents

Shenoy, Gopal; Lewellen, John; Shu, Deming; Vinokurov, Nikolai

2005-02-22

A new and improved undulator design is provided that enables a variable period length for the production of synchrotron radiation from both medium-energy and high-energy storage rings. The variable period length is achieved using a staggered array of pole pieces made up of high permeability material, permanent magnet material, or an electromagnetic structure. The pole pieces are separated by a variable width space. The sum of the variable width space and the pole width would therefore define the period of the undulator. Features and advantages of the invention include broad photon energy tunability, constant power operation and constant brilliance operation.

Non-Maxwellian Analysis of the Transition-region Line Profiles Observed by the Interface Region Imaging Spectrograph

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dudík, Jaroslav; Dzifčáková, Elena; Polito, Vanessa

2017-06-10

We investigate the nature of the spectral line profiles for transition-region (TR) ions observed with the Interface Region Imaging Spectrograph (IRIS) . In this context, we analyzed an active-region observation performed by IRIS in its 1400 Å spectral window. The TR lines are found to exhibit significant wings in their spectral profiles, which can be well fitted with a non-Maxwellian κ distribution. The fit with a κ distribution can perform better than a double-Gaussian fit, especially for the strongest line, Si iv 1402.8 Å. Typical values of κ found are about 2, occurring in a majority of spatial pixels wheremore » the TR lines are symmetric, i.e., the fit can be performed. Furthermore, all five spectral lines studied (from Si iv, O iv, and S iv) appear to have the same full-width at half-maximum irrespective of whether the line is an allowed or an intercombination transition. A similar value of κ is obtained for the electron distribution by the fitting of the line intensities relative to Si iv 1402.8 Å, if photospheric abundances are assumed. The κ distributions, however, do not remove the presence of non-thermal broadening. Instead, they actually increase the non-thermal width. This is because, for κ distributions, TR ions are formed at lower temperatures. The large observed non-thermal width lowers the opacity of the Si iv line sufficiently enough for this line to become optically thin.« less

Coronal Structures in Cool Stars

NASA Technical Reports Server (NTRS)

Oliversen, Ronald (Technical Monitor); Dupree, Andrea K.

2005-01-01

We have extended our study of the structure of coronas in cool stars to very young stars still accreting from their surrounding disks. In addition we are pursing the connection between coronal X-rays and a powerful diagnostic line in the infrared, the He I 10830Angstrom transition of helium. Highlights of these are summarized below including publications during this reporting period and presentations. Spectroscopy of the infrared He I (lambda10830) line with KECK/NIRSPEC and IRTF/CSHELL and of the ultraviolet C III (lambda977) and O VI (lambda1032) emission with FUSE reveals that the classical T Tauri star TW Hydrae exhibits P Cygni profiles, line asymmetries, and absorption indicative of a continuous, fast (approximately 400 kilometers per second), hot (approximately 300,000 K) accelerating outflow with a mass loss rate approximately 10(exp -11)-10(exp -12) solar mass yr(sup -1) or larger. Spectra of T Tauri N appear consistent with such a wind. The source of the emission and outflow seems restricted to the stars themselves. Although the mass accretion rate is an order of magnitude less for TW Hya than for T Tau, the outflow reaches higher velocities at chromospheric temperatures in TW Hya. Winds from young stellar objects may be substantially hotter and faster than previously thought. The ultraviolet emission lines, when corrected for absorption are broad. Emission associated with the accretion flow and shock is likely to show turbulent broadening. We note that the UV line widths are significantly larger than the X-ray line widths. If the X-rays from TW Hya are generated at the accretion shock, the UV lines may not be directly associated with the shock. On the other hand, studies of X-ray emission in young star clusters, suggest that the strength of the X-ray emission is correlated with stellar rotation, thus casting doubt on an accretion origin for the X-rays. We are beginning to access the infrared spectral region where the He I 108308Angstroms transition occurs. This line is particularly useful as a diagnostic of coronal radiation since it is formed by recombination following photoionization of neutral helium by coronal X-rays. Because the lower level of the transition is metastable, infrared radiation from the stellar photosphere is absorbed which provides a diagnostic of atmospheric dynamics. This transition is useful both in young stars in the T Tauri phase and in active cool star binaries. We will investigate the influence of coronal x-rays on the strength of this transition.

¹⁴N Quadrupole Resonance line broadening due to the earth magnetic field, occuring only in the case of an axially symmetric electric field gradient tensor.

PubMed

Aissani, Sarra; Guendouz, Laouès; Marande, Pierre-Louis; Canet, Daniel

2015-01-01

As demonstrated before, the application of a weak static B0 magnetic field (less than 10 G) may produce definite effects on the ¹⁴N Quadrupole Resonance line when the electric field gradient tensor at the nitrogen nucleus level is of axial symmetry. Here, we address more precisely the problem of the relative orientation of the two magnetic fields (the static field and the radio-frequency field of the pure NQR experiment). For a field of 6G, the evolution of the signal intensity, as a function of this relative orientation, is in very good agreement with the theoretical predictions. There is in particular an intensity loss by a factor of three when going from the parallel configuration to the perpendicular configuration. By contrast, when dealing with a very weak magnetic field (as the earth field, around 0.5 G), this effect drops to ca. 1.5 in the case Hexamethylenetetramine (HMT).This is explained by the fact that the Zeeman shift (due to the very weak magnetic field) becomes comparable to the natural line-width. The latter can therefore be determined by accounting for this competition. Still in the case of HMT, the estimated natural line-width is half the observed line-width. The extra broadening is thus attributed to earth magnetic field. The latter constitutes therefore the main cause of the difference between the natural transverse relaxation time (T₂) and the transverse relaxation time derived from the observed line-width (T₂(⁎)). Copyright © 2015 Elsevier Inc. All rights reserved.

THE OPTICAL STRUCTURE OF THE STARBURST GALAXY M82. II. NEBULAR PROPERTIES OF THE DISK AND INNER WIND

DOE Office of Scientific and Technical Information (OSTI.GOV)

Westmoquette, M. S.; Smith, L. J.; Konstantopoulos, I. S.

2009-12-01

In this second paper of the series, we present the results from optical Gemini-North GMOS-IFU and WIYN DensePak IFU spectroscopic observations of the starburst and inner wind zones of M82, with a focus on the state of the T approx 10{sup 4} K ionized interstellar medium. Our electron density maps show peaks of a few 1000 cm{sup -3} (implying very high thermal pressures), local small spatial-scale variations, and a falloff in the minor axis direction. We discuss the implications of these results with regards to the conditions/locations that may favor the escape of individual cluster winds that ultimately power themore » large-scale superwind. Our findings, when combined with the body of literature built up over the last decade on the state of the interstellar medium (ISM) in M82, imply that the starburst environment is highly fragmented into a range of clouds from small/dense clumps with low-filling factors (<1 pc, n {sub e} approx> 10{sup 4} cm{sup -3}) to larger filling factor, less dense gas. The most compact clouds seem to be found in the cores of the star cluster complexes, whereas the cloud sizes in the inter-complex region are larger. These dense clouds are bathed with an intense radiation field and embedded in an extensive high temperature (T approx> 10{sup 6} K), X-ray-emitting ISM that is a product of the high star formation rates in the starburst zones of M82. The near-constant state of the ionization state of the approx10{sup 4} K gas throughout the M82 starburst zone can be explained as a consequence of the small cloud sizes, which allow the gas conditions to respond quickly to any changes. In Paper I, we found that the observed emission lines are composed of multiple components, including a broad (FWHM approx 150-350 km s{sup -1}) feature that we associate with emission from turbulent mixing layers on the surfaces of the gas clouds, resulting from the interaction of the fast wind outflows from the synchrotron self-Comptons. The large number of compact clouds and wind sources provides an ideal environment for broad line emission, and explains the large observed broad/narrow-line flux ratios. We have examined in more detail the discrete outflow channel identified within the inner wind in Paper I. The channel appears as a coherent, expanding cylindrical structure of length >120 pc and width 35-50 pc. The walls maintain an approximately constant (but subsonic) expansion velocity of approx60 km s{sup -1}, and are defined by peaks and troughs in the densities of the different line components. We hypothesize that as the hot wind fluid flows down the channel cavity, it interacts with the cooler, denser walls of the channel and with entrained material within the flow to produce broad-line emission, while the walls themselves emit primarily the narrow lines. We use the channel to examine further the relationship between the narrow and broad component emitting gas within the inner wind. Within the starburst energy injection zone, we find that turbulent motions (as traced by the broad component) appear to play an increasing role with height. Finally, we have argued that a point-like knot identified in GMOS position 4, exhibiting blueshifted (by approx140 km s{sup -1}), broad (approx<350 km s{sup -1}) Halpha emission and enhanced [S II]/Halpha and [N II]/Halpha ratios, is most likely an ejected luminous blue variable-type object.« less

Measuring the ISM Content of Optically Luminous Type 2 Quasars

NASA Astrophysics Data System (ADS)

Marshall, Jameeka; Petric, Andreea; Flagey, Nicolas; Lacy, Mark; Omont, Alain

2018-01-01

There is a connection between black holes (BH) and the surrounding bulge stars. Measuring the cold interstellar medium (ISM) content of host galaxies is essential to understand the coevolution of galaxies and BHs. The ISM measurement is important because gas constitutes the raw material from which BHs grow and stars form. Quasars are extremely luminous active galaxies fueled by accreting supermassive black holes. Type 2 quasars have narrow spectral lines whereas type 1 quasars have broad spectral lines. Not only can the ISM measurements provide empirical data to help further clarify quasar models but it is also crucial in distinguishing the physical differences between type 1 and type 2 quasars. Observations of twenty type 2 quasars were made using IRAM, a single dish 30 meter radio telescope, to measure 12CO (1-0) and 12CO (2-1) emission. We used line widths to constrain the dynamical mass and gravitational potential of the host galaxy. Star formation rate (SFR) measured in the infrared (IR) and SFR derived from optical spectra were used to estimate star formation efficiency and gas depletion time scale (M H2/star formation rate). Preliminary analysis suggests that star formation efficiency in type 2 quasars is slightly higher than in type 1 quasars.

Optical spectroscopy of the recurrent nova RS Ophiuchi - from the outburst of 2006 to quiescence

NASA Astrophysics Data System (ADS)

Mondal, Anindita; Anupama, G. C.; Kamath, U. S.; Das, Ramkrishna; Selvakumar, G.; Mondal, Soumen

2018-03-01

Optical spectra of the 2006 outburst of RS Ophiuchi beginning one day after discovery to over a year after the outburst are presented here. The spectral evolution is found to be similar to that in previous outbursts. The early-phase spectra are dominated by hydrogen and helium (I and II) lines. Coronal and nebular lines appear in the later phases. Emission line widths are found to narrow with time, which is interpreted as a shock expanding into the red giant wind. Using the photoionization code CLOUDY, spectra at nine epochs spanning 14 months after the outburst peak, thus covering a broad range of ionization and excitation levels in the ejecta, are modelled. The best-fitting model parameters indicate the presence of a hot white dwarf source with a roughly constant luminosity of 1.26 × 1037 erg s-1. During the first three months, the abundances (by number) of He, N, O, Ne, Ar, Fe, Ca, S and Ni are found to be above solar abundances; the abundances of these elements decreased in the later phase. Also presented are spectra obtained during quiescence. A photoionization model of the quiescent spectrum indicates the presence of a low-luminosity accretion disc. The helium abundance is found to be subsolar at quiescence.

Mapping and characterization of the major quantitative trait locus qSS7 associated with increased length and decreased width of rice seeds.

PubMed

Qiu, Xianjin; Gong, Rong; Tan, Youbin; Yu, Sibin

2012-12-01

Seed shape in rice (Oryza sativa) is an important factor that determines grain appearance, cooking quality and grain yield. Here, we report a major quantitative trait locus qSS7 on the long arm of chromosome 7 for seed length, seed width and the ratio of seed length to width, identified using a segregating population derived from a cross between an indica variety Zhenshan97 and a chromosomal segment substitution line of a japonica variety Cypress within the genetic background of Zhenshan97. The Cypress allele at qSS7 contributes to an increase in seed length and the ratio of length to width, but a decrease in seed width, without significantly changing seed weight, plant height, heading date or number of spikelets per panicle. Using a large F(2) population generated from a substitution line that carries only a heterozygous single segment surrounding qSS7, we delimited the QTL to a 23-kb region containing two annotated genes. Progeny testing of the informative recombinants suggested that this qSS7 region is a composite QTL in which at least two genes contribute to seed length and width. Sequence comparison and expression analysis of two probable candidate genes revealed differences between the parental lines. These results will facilitate cloning of the gene(s) underlying qSS7 as well as marker-assisted transfer of desirable genes for seed shape in rice improvement.

Synchrotron radiation-based quasi-elastic scattering using time-domain interferometry with multi-line gamma rays.

PubMed

Saito, Makina; Masuda, Ryo; Yoda, Yoshitaka; Seto, Makoto

2017-10-02

We developed a multi-line time-domain interferometry (TDI) system using 14.4 keV Mössbauer gamma rays with natural energy widths of 4.66 neV from 57 Fe nuclei excited using synchrotron radiation. Electron density fluctuations can be detected at unique lengths ranging from 0.1 nm to a few nm on time scales from several nanoseconds to the sub-microsecond order by quasi-elastic gamma-ray scattering (QGS) experiments using multi-line TDI. In this report, we generalize the established expression for a time spectrum measured using an identical single-line gamma-ray emitter pair to the case of a nonidentical pair of multi-line gamma-ray emitters by considering the finite energy width of the incident synchrotron radiation. The expression obtained illustrates the unique characteristics of multi-line TDI systems, where the finite incident energy width and use of a nonidentical emitter pair produces further information on faster sub-picosecond-scale dynamics in addition to the nanosecond dynamics; this was demonstrated experimentally. A normalized intermediate scattering function was extracted from the spectrum and its relaxation form was determined for a relaxation time of the order of 1 μs, even for relatively large momentum transfer of ~31 nm -1 . The multi-line TDI method produces a microscopic relaxation picture more rapidly and accurately than conventional single-line TDI.

FLARE-LIKE VARIABILITY OF THE Mg II {lambda}2800 EMISSION LINE IN THE {gamma}-RAY BLAZAR 3C 454.3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leon-Tavares, J.; Chavushyan, V.; Patino-Alvarez, V.

2013-02-01

We report the detection of a statistically significant flare-like event in the Mg II {lambda}2800 emission line of 3C 454.3 during the outburst of autumn 2010. The highest levels of emission line flux recorded over the monitoring period (2008-2011) coincide with a superluminal jet component traversing through the radio core. This finding crucially links the broad emission line fluctuations to the non-thermal continuum emission produced by relativistically moving material in the jet and hence to the presence of broad-line region clouds surrounding the radio core. If the radio core were located at several parsecs from the central black hole, thenmore » our results would suggest the presence of broad-line region material outside the inner parsec where the canonical broad-line region is envisaged to be located. We briefly discuss the implications of broad emission line material ionized by non-thermal continuum in the context of virial black hole mass estimates and gamma-ray production mechanisms.« less

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

NASA Astrophysics Data System (ADS)

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

2013-02-01

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

Elastic tunneling identification through crossings, anti-crossings and splitting of states in the complex electronic current of systems based on mesoscopic molecules

NASA Astrophysics Data System (ADS)

López, Luis I. A.; Mendoza, Michel; Ujevic, Sebastian

2013-09-01

We have systematically studied the conductance σ( E,B) and the electronic current line shapes J( V ex ) through complex mesoscopic molecules in an elastic resonant tunneling regime. The studied systems are based on GaAs/AlGaAs hetero-structures, with several discrete states in each coupled mesoscopic molecule. The molecules were formed using different wells and barrier widths. These systems allow effective couplings and uncouplings that lead to elastic processes as a function of the electronic potential V ex and magnetic field B. In this situation, the J( V ex ) and σ( E, B) curves exhibit a sequence of peaks of difficult interpretation, in which crossings and anti-crossings (a splitting if it is generated in the resonance condition) of states contribute in a way that they cannot be easily identified. Performing a systematic analysis of the evolution of these states (before the resonance condition), we were able to determine the origin of these current peaks. We have found that the coupling of states (anti-crossing) around the resonance region can be identified as a broad mirrored- D line shape in the J( V ex ) curves. The mirrored- D line shape peaks can be clearly differentiated from the neighboring peaks because the last ones follow a very defined increasing sequence in their intensities and widths. Also, this behavior (fingerprint) can be used to identify possible splitting of states in the J( V ex ). The splittings that are generated between states with different quantum numbers (quantum numbers associated to the individual well) follow an unexpected opposite behavior when compared with those generated between states with the same quantum numbers (quasi-miniband). All these results are also observed in the conductance σ( E, B) associated with complex mesoscopic molecules based on a two-dimensional electron gas.

Effect of fjord geometry on tidewater glacier stability

NASA Astrophysics Data System (ADS)

Åkesson, Henning; Nisancioglu, Kerim H.; Nick, Faezeh M.

2016-04-01

Many marine-terminating glaciers have thinned, accelerated and retreated during the last two decades, broadly consistent with warmer atmospheric and oceanic conditions. However, these patterns involve considerable spatial and temporal variability, with diverse glacier behavior within the same regions. Similarly, reconstructions of marine-terminating glaciers indicate highly asynchronous retreat histories. While it is well known that retrograde slopes can cause marine ice sheet instabilities, the effect of lateral drag and fjord width has received less attention. Here, we test the hypothesis that marine outlet glacier stability is largely controlled by fjord width, and to a less extent by regional climate forcing. We employ a dynamic flowline model on idealized glacier geometries (representative of different outlet glaciers) to investigate geometric controls on decadal and longer times scales. The model accounts for driving and resistive stresses of glacier flow as well as along-flow stress transfer. It has a physical treatment of iceberg calving and a time-adaptive grid allowing for continuous tracking of grounding-line migration. We apply changes in atmospheric and oceanic forcing and show how wide and narrow fjord sections foster glacier (in)stabilities. We also evaluate the effect of including a surface mass balance - elevation feedback in such a setting. Finally, the relevance of these results to past and future marine-terminating glacier stability is discussed.

Numerical investigation of frequency spectrum in the Hasegawa-Wakatani model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Juhyung; Terry, P. W.

2013-10-15

The wavenumber-frequency spectrum of the two-dimensional Hasegawa-Wakatani model is investigated in the hydrodynamic, intermediate, and adiabatic regimes. A nonlinear frequency and a line width related to energy transfer properties provide a measure of the average frequency and spectral broadening, respectively. In the adiabatic regime, narrow spectra, typical of wave turbulence, are observed with a nonlinear frequency shift in the electron drift direction. In the hydrodynamic regime, broad spectra with almost zero nonlinear frequencies are observed. Nonlinear frequency shifts are shown to be related to nonlinear energy transfer by vorticity advection through the high frequency region of the spectrum. In themore » intermediate regime, the nonlinear frequency shift for density fluctuations is observed to be weaker than that of electrostatic potential fluctuations. The weaker frequency shift of the density fluctuations is due to nonlinear density advection, which favors energy transfer in the low frequency range. Both the nonlinear frequency and the spectral width increase with poloidal wavenumber k{sub y}. In addition, in the adiabatic regime where the nonlinear interactions manifest themselves in the nonlinear frequency shift, the cross-phase between the density and potential fluctuations is observed to match a linear relation, but only if the linear response of the linearly stable eigenmode branch is included. Implications of these numerical observations are discussed.« less

Isotopic niches support the resource breadth hypothesis.

PubMed

Rader, Jonathan A; Newsome, Seth D; Sabat, Pablo; Chesser, R Terry; Dillon, Michael E; Martínez Del Rio, Carlos

2017-03-01

Because a broad spectrum of resource use allows species to persist in a wide range of habitat types, and thus permits them to occupy large geographical areas, and because broadly distributed species have access to more diverse resource bases, the resource breadth hypothesis posits that the diversity of resources used by organisms should be positively related with the extent of their geographic ranges. We investigated isotopic niche width in a small radiation of South American birds in the genus Cinclodes. We analysed feathers of 12 species of Cinclodes to test the isotopic version of the resource breadth hypothesis and to examine the correlation between isotopic niche breadth and morphology. We found a positive correlation between the widths of hydrogen and oxygen isotopic niches (which estimate breadth of elevational range) and widths of the carbon and nitrogen isotopic niches (which estimates the diversity of resources consumed, and hence of habitats used). We also found a positive correlation between broad isotopic niches and wing morphology. Our study not only supports the resource breadth hypothesis but it also highlights the usefulness of stable isotope analyses as tools in the exploration of ecological niches. It is an example of a macroecological application of stable isotopes. It also illustrates the importance of scientific collections in ecological studies. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

THE LICK AGN MONITORING PROJECT: REVERBERATION MAPPING OF OPTICAL HYDROGEN AND HELIUM RECOMBINATION LINES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bentz, Misty C.; Walsh, Jonelle L.; Barth, Aaron J.

2010-06-20

We have recently completed a 64-night spectroscopic monitoring campaign at the Lick Observatory 3 m Shane telescope with the aim of measuring the masses of the black holes in 12 nearby (z < 0.05) Seyfert 1 galaxies with expected masses in the range {approx}10{sup 6}-10{sup 7} M{sub sun} and also the well-studied nearby active galactic nucleus (AGN) NGC 5548. Nine of the objects in the sample (including NGC 5548) showed optical variability of sufficient strength during the monitoring campaign to allow for a time lag to be measured between the continuum fluctuations and the response to these fluctuations in themore » broad H{beta} emission, which we have previously reported. We present here the light curves for the H{alpha}, H{gamma}, He II {lambda}4686, and He I {lambda}5876 emission lines and the time lags for the emission-line responses relative to changes in the continuum flux. Combining each emission-line time lag with the measured width of the line in the variable part of the spectrum, we determine a virial mass of the central supermassive black hole from several independent emission lines. We find that the masses are generally consistent within the uncertainties. The time-lag response as a function of velocity across the Balmer line profiles is examined for six of the AGNs. We find similar responses across all three Balmer lines for Arp 151, which shows a strongly asymmetric profile, and for SBS 1116+583A and NGC 6814, which show a symmetric response about zero velocity. For the other three AGNs, the data quality is somewhat lower and the velocity-resolved time-lag response is less clear. Finally, we compare several trends seen in the data set against the predictions from photoionization calculations as presented by Korista and Goad. We confirm several of their predictions, including an increase in responsivity and a decrease in the mean time lag as the excitation and ionization level for the species increases. Specifically, we find the time lags of the optical recombination lines to have weighted mean ratios of {tau}(H{alpha}):{tau}(H{beta}):{tau}(H{gamma}):{tau}(He I):{tau}(He II) = 1.54:1.00:0.61:0.36:0.25. Further confirmation of photoionization predictions for broad-line gas behavior will require additional monitoring programs for these AGNs while they are in different luminosity states.« less

On the Detectability of Oxygen X-Ray Fluorescence and Its Use as a Solar Photospheric Abundance Diagnostic

NASA Astrophysics Data System (ADS)

Drake, Jeremy J.; Ercolano, Barbara

2008-08-01

Monte Carlo calculations of the O Kα line fluoresced by coronal X-rays and emitted just above the temperature minimum region of the solar atmosphere have been employed to investigate the use of this feature as an abundance diagnostic. While they are quite weak, we estimate line equivalent widths in the range 0.02-0.2 Å, depending on the X-ray plasma temperature. The line remains essentially uncontaminated by blends for coronal temperatures T <= 3 × 106 K and should be quite observable, with a flux gtrsim2 photons s-1 arcmin-2. Model calculations for solar chemical mixtures with an O abundance adjusted up and down by a factor of 2 indicate 35%-60% changes in O Kα line equivalent width, providing a potentially useful O abundance diagnostic. Sensitivity of equivalent width to differences between recently recommended chemical compositions with "high" and "low" complements of the CNO trio important for interpreting helioseismological observations is less acute, amounting to 20%-26% at coronal temperatures T <= 2 × 106 K. While still feasible for discriminating between these two mixtures, uncertainties in measured line equivalent widths and in the models used for interpretation would need to be significantly less than 20%. Provided a sensitive X-ray spectrometer with resolving power >=1000 and suitably well-behaved instrumental profile can be built, X-ray fluorescence presents a viable means for resolving the solar "oxygen crisis."

Black hole masses in active galactic nuclei

NASA Astrophysics Data System (ADS)

Denney, Kelly D.

2010-11-01

We present the complete results from two, high sampling-rate, multi-month, spectrophotometric reverberation mapping campaigns undertaken to obtain either new or improved Hbeta reverberation lag measurements for several relatively low-luminosity active galactic nuclei (AGNs). We have reliably measured the time delay between variations in the continuum and Hbeta emission line in seven local Seyfert 1 galaxies. These measurements are used to calculate the mass of the supermassive black hole at the center of each of these AGNs. We place our results in context to the most current calibration of the broad-line region (BLR) RBLR-L relationship, where our results remove many outliers and significantly reduce the scatter at the low-luminosity end of this relationship. A detailed analysis of the data from our high sampling rate, multi-month reverberation mapping campaign in 2007 reveals that the Hbeta emission region within the BLRs of several nearby AGNs exhibit a variety of kinematic behaviors. Through a velocity-resolved reverberation analysis of the broad Hbeta emission-line flux variations in our sample, we reconstruct velocity-resolved kinematic signals for our entire sample and clearly see evidence for outflowing, infalling, and virialized BLR gas motions in NGC 3227, NGC 3516, and NGC 5548, respectively. Finally, we explore the nature of systematic errors that can arise in measurements of black hole masses from single-epoch spectra of AGNs by utilizing the many epochs available for NGC 5548 and PG1229+204 from reverberation mapping databases. In particular, we examine systematics due to AGN variability, contamination due to constant spectral components (i.e., narrow lines and host galaxy flux), data quality (i.e., signal-to-noise ratio, S/N), and blending of spectral features. We investigate the effect that each of these systematics has on the precision and accuracy of single-epoch masses calculated from two commonly-used line-width measures by comparing these results to recent reverberation mapping studies. We then present an error budget which summarizes the minimum observable uncertainties as well as the amount of additional scatter and/or systematic offset that can be expected from the individual sources of error investigated.

Shining a light on galactic outflows: photoionized outflows

NASA Astrophysics Data System (ADS)

Chisholm, John; Tremonti, Christy A.; Leitherer, Claus; Chen, Yanmei; Wofford, Aida

2016-04-01

We study the ionization structure of galactic outflows in 37 nearby, star-forming galaxies with the Cosmic Origins Spectrograph on the Hubble Space Telescope. We use the O I, Si II, Si III, and Si IV ultraviolet absorption lines to characterize the different ionization states of outflowing gas. We measure the equivalent widths, line widths, and outflow velocities of the four transitions, and find shallow scaling relations between them and galactic stellar mass and star formation rate. Regardless of the ionization potential, lines of similar strength have similar velocities and line widths, indicating that the four transitions can be modelled as a comoving phase. The Si equivalent width ratios (e.g. Si IV/Si II) have low dispersion, and little variation with stellar mass; while ratios with O I and Si vary by a factor of 2 for a given stellar mass. Photoionization models reproduce these equivalent width ratios, while shock models under predict the relative amount of high ionization gas. The photoionization models constrain the ionization parameter (U) between -2.25 < log (U) < -1.5, and require that the outflow metallicities are greater than 0.5 Z⊙. We derive ionization fractions for the transitions, and show that the range of ionization parameters and stellar metallicities leads to a factor of 1.15-10 variation in the ionization fractions. Historically, mass outflow rates are calculated by converting a column density measurement from a single metal ion into a total hydrogen column density using an ionization fraction, thus mass outflow rates are sensitive to the assumed ionization structure of the outflow.

Maskless Lithography Using Negative Photoresist Material: Impact of UV Laser Intensity on the Cured Line Width

NASA Astrophysics Data System (ADS)

Mohammed, Mohammed Ziauddin; Mourad, Abdel-Hamid I.; Khashan, Saud A.

2018-06-01

The application of maskless lithography technique on negative photoresist material is investigated in this study. The equipment used in this work is designed and built especially for maskless lithography applications. The UV laser of 405 nm wavelength with 0.85 Numerical Aperture is selected for direct laser writing. All the samples are prepared on a glass substrate. Samples are tested at different UV laser intensities and different stage velocities in order to study the impact on patterned line width. Three cases of spin coated layers of thickness 90 μm, 40 μm, and 28 μm on the substrate are studied. The experimental results show that line width has a generally increasing trend with intensity. However, a decreasing trend was observed for increasing velocity. The overall performance shows that the mr-DWL material is suitable for direct laser writing systems.

Automatic alternative phase-shift mask CAD layout tool for gate shrinkage of embedded DRAM in logic below 0.18 μm

NASA Astrophysics Data System (ADS)

Ohnuma, Hidetoshi; Kawahira, Hiroichi

1998-09-01

An automatic alternative phase shift mask (PSM) pattern layout tool has been newly developed. This tool is dedicated for embedded DRAM in logic device to shrink gate line width with improving line width controllability in lithography process with a design rule below 0.18 micrometers by the KrF excimer laser exposure. The tool can crete Levenson type PSM used being coupled with a binary mask adopting a double exposure method for positive photo resist. By using graphs, this tool automatically creates alternative PSM patterns. Moreover, it does not give any phase conflicts. By adopting it to actual embedded DRAM in logic cells, we have provided 0.16 micrometers gate resist patterns at both random logic and DRAM areas. The patterns were fabricated using two masks with the double exposure method. Gate line width has been well controlled under a practical exposure-focus window.

Maskless Lithography Using Negative Photoresist Material: Impact of UV Laser Intensity on the Cured Line Width

NASA Astrophysics Data System (ADS)

Mohammed, Mohammed Ziauddin; Mourad, Abdel-Hamid I.; Khashan, Saud A.

2018-04-01

The application of maskless lithography technique on negative photoresist material is investigated in this study. The equipment used in this work is designed and built especially for maskless lithography applications. The UV laser of 405 nm wavelength with 0.85 Numerical Aperture is selected for direct laser writing. All the samples are prepared on a glass substrate. Samples are tested at different UV laser intensities and different stage velocities in order to study the impact on patterned line width. Three cases of spin coated layers of thickness 90 μm, 40 μm, and 28 μm on the substrate are studied. The experimental results show that line width has a generally increasing trend with intensity. However, a decreasing trend was observed for increasing velocity. The overall performance shows that the mr-DWL material is suitable for direct laser writing systems.

Fine pattern replication on 10 x 10-mm exposure area using ETS-1 laboratory tool in HIT

NASA Astrophysics Data System (ADS)

Hamamoto, K.; Watanabe, Takeo; Hada, Hideo; Komano, Hiroshi; Kishimura, Shinji; Okazaki, Shinji; Kinoshita, Hiroo

2002-07-01

Utilizing ETS-1 laboratory tool in Himeji Institute of Technology (HIT), as for the fine pattern replicated by using the Cr mask in static exposure, it is replicated in the exposure area of 10 mm by 2 mm in size that the line and space pattern width of 60 nm, the isolated line pattern width of 40 nm, and hole pattern width of 150 nm. According to the synchronous scanning of the mass and wafer with EUVL laboratory tool with reduction optical system which consisted of three-aspherical-mirror in the NewSUBARU facilities succeeded in the line of 60 nm and the space pattern formation in the exposure region of 10mm by 10mm. From the result of exposure characteristics for positive- tone resist for KrF and EB, KrF chemically amplified resist has better characteristics than EB chemically amplified resist.

Ecoregions and stream morphology in eastern Oklahoma

USGS Publications Warehouse

Splinter, D.K.; Dauwalter, D.C.; Marston, R.A.; Fisher, W.L.

2010-01-01

Broad-scale variables (i.e., geology, topography, climate, land use, vegetation, and soils) influence channel morphology. How and to what extent the longitudinal pattern of channel morphology is influenced by broad-scale variables is important to fluvial geomorphologists and stream ecologists. In the last couple of decades, there has been an increase in the amount of interdisciplinary research between fluvial geomorphologists and stream ecologists. In a historical context, fluvial geomorphologists are more apt to use physiographic regions to distinguish broad-scale variables, while stream ecologists are more apt to use the concept of an ecosystem to address the broad-scale variables that influence stream habitat. For this reason, we designed a study using ecoregions, which uses physical and biological variables to understand how landscapes influence channel processes. Ecoregions are delineated by similarities in geology, climate, soils, land use, and potential natural vegetation. In the fluvial system, stream form and function are dictated by processes observed throughout the fluvial hierarchy. Recognizing that stream form and function should differ by ecoregion, a study was designed to evaluate how the characteristics of stream channels differed longitudinally among three ecoregions in eastern Oklahoma, USA: Boston Mountains, Ozark Highlands, and Ouachita Mountains. Channel morphology of 149 stream reaches was surveyed in 1st- through 4th-order streams, and effects of drainage area and ecoregion on channel morphology was evaluated using multiple regressions. Differences existed (?????0.05) among ecoregions for particle size, bankfull width, and width/depth ratio. No differences existed among ecoregions for gradient or sinuosity. Particle size was smallest in the Ozark Highlands and largest in the Ouachita Mountains. Bankfull width was larger in the Ozark Highlands than in the Boston Mountains and Ouachita Mountains in larger streams. Width/depth ratios of the Boston Mountains and Ozark Highlands were not statistically different. Significant differences existed, however, between the Boston Mountains and Ozark Highlands when compared individually to the Ouachita Mountains. We found that ecoregions afforded a good spatial structure that can help in understanding longitudinal trends in stream reach morphology surveyed at the reach scale. The hierarchy of the fluvial system begins within a broad, relatively homogenous setting that imparts control on processes that affect stream function. Ecoregions provide an adequate regional division to begin a large-scale geomorphic study of processes in stream channels. ?? 2010 Elsevier B.V.

Cavity detection and delineation research. Part 4: Microgravimetric survey: Manatee Springs Site, Florida

NASA Astrophysics Data System (ADS)

Butler, D. K.; Whitten, C. B.; Smith, F. L.

1983-03-01

Results of a microgravimetric survey at Manatee Springs, Levy County, Fla., are presented. The survey area was 100 by 400 ft, with 20-ft gravity station spacing, and with the long dimension of the area approximately perpendicular to the known trend of the main cavity. The main cavity is about 80 to 100 ft below the surface and has a cross section about 16 to 20 ft in height and 30 to 40 ft in width beneath the survey area. Using a density contrast of -1.3 g/cucm, the gravity anomaly is calculated to be -35 micro Gal with a width at half maximum of 205 ft. The microgravimetric survey results clearly indicate a broad negative anomaly coincident with the location and trend of the cavity system across the survey area. The anomaly magnitude and width are consistent with those calculated from the known depth and dimensions of the main cavity. In addition, a small, closed negative anomaly feature, superimposed on the broad negative feature due to the main cavity, satisfactorily delineated a small secondary cavity feature which was discovered and mapped by cave divers.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leighly, Karen M.; Baron, Eddie; Lucy, Adrian B.

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 fullmore » 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.« less

VizieR Online Data Catalog: Blazars equivalent widths and radio luminosity (Landt+, 2004)

NASA Astrophysics Data System (ADS)

Landt, H.; Padovani, P.; Perlman, E. S.; Giommi, P.

2004-07-01

Blazars are currently separated into BL Lacertae objects (BL Lacs) and flat spectrum radio quasars based on the strength of their emission lines. This is performed rather arbitrarily by defining a diagonal line in the Ca H&K break value-equivalent width plane, following Marcha et al. (1996MNRAS.281..425M). We readdress this problem and put the classification scheme for blazars on firm physical grounds. We study ~100 blazars and radio galaxies from the Deep X-ray Radio Blazar Survey (DXRBS, Cat. and ) and 2-Jy radio survey and find a significant bimodality for the narrow emission line [OIII]{lambda}5007. This suggests the presence of two physically distinct classes of radio-loud active galactic nuclei (AGN). We show that all radio-loud AGN, blazars and radio galaxies, can be effectively separated into weak- and strong-lined sources using the [OIII]{lambda}5007-[OII]{lambda}3727 equivalent width plane. This plane allows one to disentangle orientation effects from intrinsic variations in radio-loud AGN. Based on DXRBS, the strongly beamed sources of the new class of weak-lined radio-loud AGN are made up of BL Lacs at the ~75 per cent level, whereas those of the strong-lined radio-loud AGN include mostly (~97 per cent) quasars. (4 data files).

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hidalgo, Paola Rodriguez; Eracleous, Michael; Charlton, Jane

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 broadmore » 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.« less

Super-massive binary black holes and emission lines in active galactic nuclei

NASA Astrophysics Data System (ADS)

Popović, Luka Č.

2012-02-01

It is now agreed that mergers play an essential role in the evolution of galaxies and therefore that mergers of supermassive black holes (SMBHs) must have been common. We see the consequences of past supermassive binary black holes (SMBs) in the light profiles of so-called 'core ellipticals' and a small number of SMBs have been detected. However, the evolution of SMBs is poorly understood. Theory predicts that SMBs should spend a substantial amount of time orbiting at velocities of a few thousand kilometers per second. If the SMBs are surrounded by gas observational effects might be expected from accretion onto one or both of the SMBHs. This could result in a binary Active Galactic Nucleus (AGN) system. Like a single AGN, such a system would emit a broad band electromagnetic spectrum and broad and narrow emission lines. The broad emission spectral lines emitted from AGNs are our main probe of the geometry and physics of the broad line region (BLR) close to the SMBH. There is a group of AGNs that emit very broad and complex line profiles, showing two displaced peaks, one blueshifted and one redshifted from the systemic velocity defined by the narrow lines, or a single such peak. It has been proposed that such line shapes could indicate an SMB system. We discuss here how the presence of an SMB will affect the BLRs of AGNs and what the observational consequences might be. We review previous claims of SMBs based on broad line profiles and find that they may have non-SMB explanations as a consequence of a complex BLR structure. Because of these effects it is very hard to put limits on the number of SMBs from broad line profiles. It is still possible, however, that unusual broad line profiles in combination with other observational effects (line ratios, quasi-periodical oscillations, spectropolarimetry, etc.) could be used for SMBs detection. Some narrow lines (e.g., [O III]) in some AGNs show a double-peaked profile. Such profiles can be caused by streams in the Narrow Line Region (NLR), but may also indicate the presence of a kilo-parsec scale mergers. A few objects indicated as double-peaked narrow line emitters are confirmed as kpc-scale margers, but double-peaked narrow line profiles are mostly caused by the complex NLR geometry. We briefly discuss the expected line profile of broad Fe Kα that probably originated in the accretion disk(s) around SMBs. This line may also be very complex and indicate the complex disk geometry or/and an SMB presence. Finally we consider rare configurations where a SMB system might be gravitationally lensed by a foreground galaxy, and discuss the expected line profiles in these systems.

Detection of Broad Hα Emission Lines in the Late-Time Spectra of a Hydrogen-Poor Superluminous Supernova

DOE PAGES

Yan, Lin; Quimby, R.; Ofek, E.; ...

2015-11-23

iPTF13ehe is a hydrogen-poor superluminous supernova (SLSN) at z = 0.3434, with a slow-evolving light curve and spectral features similar to SN2007bi. It rises in 83–148 days to reach a peak bolometric luminosity of ~1.3 × 10 44 erg s -1, then decays slowly at 0.015 mag day -1. The measured ejecta velocity is ~ 13,000 km s -1. The inferred explosion characteristics, such as the ejecta mass (70–220 M ⊙), and the total radiative and kinetic energy (E rad ~ 10 51 erg, E kin ~ 2 × 10 53 erg), are typical of slow-evolving H-poor SLSN events. However,more » the late-time spectrum taken at +251 days (rest, post-peak) reveals a Balmer Hα emission feature with broad and narrow components, which has never been detected before among other H-poor SLSNe. The broad component has a velocity width of ~4500 km s -1 and a ~300 km s -1 blueward shift relative to the narrow component. In this paper, we interpret this broad Hα emission with a luminosity of ~2 × 10 41 erg s -1 as resulting from the interaction between the supernova ejecta and a discrete H-rich shell, located at a distance of ~4 × 10 16 cm from the explosion site. This interaction causes the rest-frame r-band LC to brighten at late times. The fact that the late-time spectra are not completely absorbed by the shock-ionized H-shell implies that its Thomson scattering optical depth is likely ≤1, thus setting upper limits on the shell mass ≤30 M ⊙. Of the existing models, a Pulsational Pair Instability supernova model can naturally explain the observed 30 M ⊙ H-shell, ejected from a progenitor star with an initial mass of (95–150) M ⊙ about 40 years ago. Finally, we estimate that at least ~15% of all SLSNe-I may have late-time Balmer emission lines.« less

Measurements of solar transition zone velocities and line broadening using the ultraviolet spectrometer and polarimeter on the Solar Maximum Mission

NASA Technical Reports Server (NTRS)

Simon, G.; Mein, P.; Vial, J. C.; Shine, R. A.; Woodgate, B. E.

1982-01-01

The UVSP instrument on SMM is able to observe solar regions at two wavelengths in the same line with a band-pass of 0.3 A. Intensity and Doppler velocity maps are derived. It is shown that the numerical values are sensitive to the adopted Doppler width and the range of velocities is limited to within 30 km/sec. A method called Double Dopplergram Determination (DDD) is described for deriving both the Doppler width and the velocity (up to 80 km/sec), and the main sources of uncertainties are discussed. To illustrate the method, a set of C IV 1548 A observations is analyzed according to this procedure. The mean C IV Doppler width measured (0.15 A) is comparable to previous determinations. A relation is found between bright regions and down-flows. Large Doppler widths correspond to strong velocity gradients.

The Iron Abundance of IOTA Herculis From Ultraviolet Iron Lines

NASA Astrophysics Data System (ADS)

Grigsby, J.; Mulliss, C.; Baer, G.

1995-03-01

We have obtained (Adelman 1992, 1993, private comunication) coadded, high-resolution IUE spectra of Iota Herculis (B3 IV) in both short wavelength (SWP) and long wavelength (LWP) regions. The spectra span the ultraviolet spectrum from 110 - 300 nm and have a SNR of roughly 30 -50; they are described in Adelman et. al. (1993, ApJ 419, 276). Abundance indicators were 54 lines of Fe II and 26 lines of Fe III whose atomic parameters have been measured in the laboratory. LTE synthetic spectra for comparison with observations were produced with the Kurucz model atmosphere and spectral synthesis codes ATLAS9/SYNTHE (Kurucz 1979, ApJS 40,1; Kurucz and Avrett 1981, SAO Special Report 391). Model parameters were chosen from the literature: effective temperature = 17500 K, log g =3.75, v sin i= 11 km/s, and turbulent velocity = 0 km/s. (Peters and Polidan 1985, in IAU Symposium 111, ed. D. S. Hayes et al. (Dordrecht: Reidel), 417). We determined the equivalent widths of the chosen lines by fitting gaussian profiles to the lines and by measuring the equivalent widths of the gaussians. We derived abundances by fitting a straight line to a plot of observed equivalent widths vs. synthetic equivalent widths; we adjusted the iron abundance of the models until a slope of unity was achieved. The abundances derived from the different ionization stages are in agreement: Fe II lines indicate an iron abundance that is 34 +15/-10% the solar value([Fe/H]=-0.47 +0.16-0.15dex), while from Fe III lines we obtain 34 +/- 10% ([Fe/H]=-0.47 +0.11/-0.15 dex). A search of the literature suggests that no previous investigations of this star's iron abundance have found agreement between the different ionization stages. We thank Saul Adelman for his generous assistance, and the Faculty Research Fund Board of Wittenberg University for support of this research.

Intrinsic line shape of electromagnetic radiation from a stack of intrinsic Josephson junctions synchronized by an internal cavity resonance

NASA Astrophysics Data System (ADS)

Koshelev, Alexei

2013-03-01

Stacks of intrinsic Josephson-junctions are realized in mesas fabricated out of layered superconducting single crystals, such as Bi2Sr2CaCu2O8 (BSCCO). Synchronization of phase oscillations in different junctions can be facilitated by the coupling to the internal cavity mode leading to powerful and coherent electromagnetic radiation in the terahertz frequency range. An important characteristic of this radiation is the shape of the emission line. A finite line width appears due to different noise sources leading to phase diffusion. We investigated the intrinsic line shape caused by the thermal noise for a mesa fabricated on the top of a BSCCO single crystal. In the ideal case of fully synchronized stack the finite line width is coming from two main contributions, the quasiparticle-current noise inside the mesa and the fluctuating radiation in the base crystal. We compute both contributions and conclude that for realistic mesa's parameters the second mechanism typically dominates. The role of the cavity quality factor in the emission line spectrum is clarified. Analytical results were verified by numerical simulations. In real mesa structures part of the stack may not be synchronized and chaotic dynamics of unsynchronized junctions may determine the real line width. Work supported by UChicago Argonne, LLC, under contract No. DE-AC02-06CH11357.

Comprehensive analysis of line-edge and line-width roughness for EUV lithography

NASA Astrophysics Data System (ADS)

Bonam, Ravi; Liu, Chi-Chun; Breton, Mary; Sieg, Stuart; Seshadri, Indira; Saulnier, Nicole; Shearer, Jeffrey; Muthinti, Raja; Patlolla, Raghuveer; Huang, Huai

2017-03-01

Pattern transfer fidelity is always a major challenge for any lithography process and needs continuous improvement. Lithographic processes in semiconductor industry are primarily driven by optical imaging on photosensitive polymeric material (resists). Quality of pattern transfer can be assessed by quantifying multiple parameters such as, feature size uniformity (CD), placement, roughness, sidewall angles etc. Roughness in features primarily corresponds to variation of line edge or line width and has gained considerable significance, particularly due to shrinking feature sizes and variations of features in the same order. This has caused downstream processes (Etch (RIE), Chemical Mechanical Polish (CMP) etc.) to reconsider respective tolerance levels. A very important aspect of this work is relevance of roughness metrology from pattern formation at resist to subsequent processes, particularly electrical validity. A major drawback of current LER/LWR metric (sigma) is its lack of relevance across multiple downstream processes which effects material selection at various unit processes. In this work we present a comprehensive assessment of Line Edge and Line Width Roughness at multiple lithographic transfer processes. To simulate effect of roughness a pattern was designed with periodic jogs on the edges of lines with varying amplitudes and frequencies. There are numerous methodologies proposed to analyze roughness and in this work we apply them to programmed roughness structures to assess each technique's sensitivity. This work also aims to identify a relevant methodology to quantify roughness with relevance across downstream processes.

An Extreme, Blueshifted Iron Line in the Narrow Line Seyfert 1 PG 1402+261

NASA Technical Reports Server (NTRS)

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

2004-01-01

We report on a short, XMM-Newton observation of the radio-quiet Narrow Line Seyfert 1 PG 1402+261. The EPIC X-ray spectrum of PG 1402+261 shows a strong excess of counts between 6 - 9 keV in the rest frame. This feature can be modeled by an unusually strong (equivalent width 2 keV) and very broad energy at 7.3 keV appears blue-shifted with respect to the iron Kalpha emission band between 6.4 - 6.97 keV, whilst 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 greater than 60 degrees 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 PG1402+261 above 2 keV is dominated by the pure-reflection component from the disk, whilst little or none of the direct hard power-law is observed. Alternatively the spectrum above 2 keV may instead be explained by an ionized absorber, if the column density is sufficiently high (NH greater than 3 x 10(exp 23) per square centimeter) and if the matter is ionized enough to produce a deep (tau approximately equal to 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 which appear to be observed in several other high accretion rate AGN. Further observations, especially at higher spectral resolution, are required to distinguish between the accretion disk reflection or outflow scenarios.

Extremely red quasars in BOSS

NASA Astrophysics Data System (ADS)

Hamann, Fred; Zakamska, Nadia L.; Ross, Nicholas; Paris, Isabelle; Alexandroff, Rachael M.; Villforth, Carolin; Richards, Gordon T.; Herbst, Hanna; Brandt, W. Niel; Cook, Ben; Denney, Kelly D.; Greene, Jenny E.; Schneider, Donald P.; Strauss, Michael A.

2017-01-01

Red quasars are candidate young objects in an early transition stage of massive galaxy evolution. Our team recently discovered a population of extremely red quasars (ERQs) in the Baryon Oscillation Spectroscopic Survey (BOSS) that has a suite of peculiar emission-line properties including large rest equivalent widths (REWs), unusual `wingless' line profiles, large N V/Lyα, N V/C IV, Si IV/C IV and other flux ratios, and very broad and blueshifted [O III] λ5007. Here we present a new catalogue of C IV and N V emission-line data for 216 188 BOSS quasars to characterize the ERQ line properties further. We show that they depend sharply on UV-to-mid-IR colour, secondarily on REW(C IV), and not at all on luminosity or the Baldwin Effect. We identify a `core' sample of 97 ERQs with nearly uniform peculiar properties selected via I-W3 ≥ 4.6 (AB) and REW(C IV) ≥ 100 Å at redshifts 2.0-3.4. A broader search finds 235 more red quasars with similar unusual characteristics. The core ERQs have median luminosity ˜ 47.1, sky density 0.010 deg-2, surprisingly flat/blue UV spectra given their red UV-to-mid-IR colours, and common outflow signatures including BALs or BAL-like features and large C IV emission-line blueshifts. Their SEDs and line properties are inconsistent with normal quasars behind a dust reddening screen. We argue that the core ERQs are a unique obscured quasar population with extreme physical conditions related to powerful outflows across the line-forming regions. Patchy obscuration by small dusty clouds could produce the observed UV extinctions without substantial UV reddening.

Homogeneous and inhomogeneous broadenings and the Voigt line shapes in the phase-resolved and intensity sum-frequency generation vibrational spectroscopy.

PubMed

Chen, Shun-Li; Fu, Li; Gan, Wei; Wang, Hong-Fei

2016-01-21

In this report, we show that the ability to measure the sub-1 cm(-1) resolution phase-resolved and intensity high-resolution broadband sum frequency generation vibrational spectra of the -CN stretch vibration of the Langmuir-Blodgett (LB) monolayer of the 4-n-octyl-4'-cyanobiphenyl (8CB) on the z-cut α-quartz surface allows the direct comparison and understanding of the homogeneous and inhomogeneous broadenings in the imaginary and intensity SFG vibrational spectral line shapes in detail. The difference of the full width at half maximum (FWHM) of the imaginary and intensity sum-frequency generation vibrational spectroscopy spectra of the same vibrational mode is the signature of the Voigt line shape and it measures the relative contribution to the overall line shape from the homogeneous and inhomogeneous broadenings in SFG vibrational spectra. From the phase-resolved and intensity spectra, we found that the FWHM of the 2238.00 ± 0.02 cm(-1) peak in the phase-resolved imaginary and intensity spectra is 19.2 ± 0.2 cm(-1) and 21.6 ± 0.4 cm(-1), respectively, for the -CN group of the 8CB LB monolayer on the z-cut α-quartz crystal surface. The FWHM width difference of 2.4 cm(-1) agrees quantitatively with a Voigt line shape with a homogeneous broadening half width of Γ = 5.29 ± 0.08 cm(-1) and an inhomogeneous standard derivation width Δω = 5.42 ± 0.07 cm(-1). These results shed new lights on the understanding and interpretation of the line shapes of both the phase-resolved and the intensity SFG vibrational spectra, as well as other incoherent and coherent spectroscopic techniques in general.

External cavity diode laser setup with two interference filters

NASA Astrophysics Data System (ADS)

Martin, Alexander; Baus, Patrick; Birkl, Gerhard

2016-12-01

We present an external cavity diode laser setup using two identical, commercially available interference filters operated in the blue wavelength range around 450 nm. The combination of the two filters decreases the transmission width, while increasing the edge steepness without a significant reduction in peak transmittance. Due to the broad spectral transmission of these interference filters compared to the internal mode spacing of blue laser diodes, an additional locking scheme, based on Hänsch-Couillaud locking to a cavity, has been added to improve the stability. The laser is stabilized to a line in the tellurium spectrum via saturation spectroscopy, and single-frequency operation for a duration of two days is demonstrated by monitoring the error signal of the lock and the piezo drive compensating the length change of the external resonator due to air pressure variations. Additionally, transmission curves of the filters and the spectra of a sample of diodes are given.

A reassessment of absolute energies of the x-ray L lines of lanthanide metals

NASA Astrophysics Data System (ADS)

Fowler, J. W.; Alpert, B. K.; Bennett, D. A.; Doriese, W. B.; Gard, J. D.; Hilton, G. C.; Hudson, L. T.; Joe, Y.-I.; Morgan, K. M.; O'Neil, G. C.; Reintsema, C. D.; Schmidt, D. R.; Swetz, D. S.; Szabo, C. I.; Ullom, J. N.

2017-08-01

We introduce a new technique for determining x-ray fluorescence line energies and widths, and we present measurements made with this technique of 22 x-ray L lines from lanthanide-series elements. The technique uses arrays of transition-edge sensors, microcalorimeters with high energy-resolving power that simultaneously observe both calibrated x-ray standards and the x-ray emission lines under study. The uncertainty in absolute line energies is generally less than 0.4 eV in the energy range of 4.5 keV to 7.5 keV. Of the seventeen line energies of neodymium, samarium, and holmium, thirteen are found to be consistent with the available x-ray reference data measured after 1990; only two of the four lines for which reference data predate 1980, however, are consistent with our results. Five lines of terbium are measured with uncertainties that improve on those of existing data by factors of two or more. These results eliminate a significant discrepancy between measured and calculated x-ray line energies for the terbium L l line (5.551 keV). The line widths are also measured, with uncertainties of 0.6 eV or less on the full-width at half-maximum in most cases. These measurements were made with an array of approximately one hundred superconducting x-ray microcalorimeters, each sensitive to an energy band from 1 keV to 8 keV. No energy-dispersive spectrometer has previously been used for absolute-energy estimation at this level of accuracy. Future spectrometers, with superior linearity and energy resolution, will allow us to improve on these results and expand the measurements to more elements and a wider range of line energies.

Broadband optical frequency comb generator based on driving N-cascaded modulators by Gaussian-shaped waveform

NASA Astrophysics Data System (ADS)

Hmood, Jassim K.; Harun, Sulaiman W.

2018-05-01

A new approach for realizing a wideband optical frequency comb (OFC) generator based on driving cascaded modulators by a Gaussian-shaped waveform, is proposed and numerically demonstrated. The setup includes N-cascaded MZMs, a single Gaussian-shaped waveform generator, and N-1 electrical time delayer. The first MZM is driven directly by a Gaussian-shaped waveform, while delayed replicas of the Gaussian-shaped waveform drive the other MZMs. An analytical model that describes the proposed OFC generator is provided to study the effect of number and chirp factor of cascaded MZM as well as pulse width on output spectrum. Optical frequency combs at frequency spacing of 1 GHz are generated by applying Gaussian-shaped waveform at pulse widths ranging from 200 to 400 ps. Our results reveal that, the number of comb lines is inversely proportional to the pulse width and directly proportional to both number and chirp factor of cascaded MZMs. At pulse width of 200 ps and chirp factor of 4, 67 frequency lines can be measured at output spectrum of two-cascaded MZMs setup. Whereas, increasing the number of cascaded stages to 3, 4, and 5, the optical spectra counts 89, 109 and 123 frequency lines; respectively. When the delay time is optimized, 61 comb lines can be achieved with power fluctuations of less than 1 dB for five-cascaded MZMs setup.

Slope mass movements on rocky sea-cliffs: A power-law distributed natural hazard on the Barlavento Coast, Algarve, Portugal

NASA Astrophysics Data System (ADS)

Teixeira, Sebastião Braz

2006-06-01

The coast of the Central Algarve, Portugal, is dominated by sea-cliffs, cut on Miocene calcarenites; here, the main coastal geologic hazards result from the conflict between human occupation and sea-cliff recession. The evolution of this rocky coast occurs through an intermittent and discontinuous series of slope mass movements, along a 46 km cliff front. For the last 30 years, the increase of tourism occupation has amplified the risks to both people and buildings. In the last decade we have seen several accidents caused by cliff failure, which killed or wounded people and destroyed several buildings. The definition of buffer zones limited by hazard lines parallel to the cliff edge, where land use is restricted, is a widely used and effective preventive measure for mitigating risk. Rocky coasts typically show a slow cliff evolution. The process of gathering statistically significant field inventories of mass movements is, thus, very long. Although mass movement catalogues provide fundamental information on sea cliff evolution patterns and are an outstanding tool in hazard assessment, published data sets are still rare. In this work, we use two inventories of mass movement width, recorded on sea cliffs cut on Miocene calcarenites: a nine year long continuous field inventory (1995-2004) with 140 recorded events, and a 44 year long catalogue based on comparative analysis of aerial photographs (1947-1991), that includes 177 events. The cumulative frequency-width distributions of both data sets fit, above a critical width value corresponding to the threshold of full completeness of the inventories, to power-law distributions. The knowledge of the limits of the catalogues enabled the construction of a 53 year long record inventory over the range of mean width ⩾3 m ( n=167 events) and maximum width ⩾4 m ( n=155 events). The data assembled corresponds to a partial series and was converted to a return period-size distribution. Both return period-width distributions (mean width and maximum width) are also power-law distributions. Equations of return period-width distributions give the width of hazard lines corresponding to the width of mass movement, in which return period equals the period that hazard line is referred to.

A Gaussian measure of quantum phase noise

NASA Technical Reports Server (NTRS)

Schleich, Wolfgang P.; Dowling, Jonathan P.

1992-01-01

We study the width of the semiclassical phase distribution of a quantum state in its dependence on the average number of photons (m) in this state. As a measure of phase noise, we choose the width, delta phi, of the best Gaussian approximation to the dominant peak of this probability curve. For a coherent state, this width decreases with the square root of (m), whereas for a truncated phase state it decreases linearly with increasing (m). For an optimal phase state, delta phi decreases exponentially but so does the area caught underneath the peak: all the probability is stored in the broad wings of the distribution.

Sonographic analysis of the intercostal spaces for the application of high-intensity focused ultrasound therapy to the liver.

PubMed

Kim, Young-Sun; Park, Min Jung; Rhim, Hyunchul; Lee, Min Woo; Lim, Hyo Keun

2014-07-01

The purposes of this study were to assess the widths of the intercostal spaces of the right inferior human rib cage through which high-intensity focused ultrasound therapy would be applied for treating liver cancer and to elucidate the demographic factors associated with intercostal space width. From March 2013 to June 2013, the widths of the intercostal spaces and the ribs at six areas of the right inferior rib cage (area 1, lowest intercostal space on anterior axillary line and the adjacent upper rib; area 2, second-lowest intercostal space on anterior axillary line and the adjacent upper rib; areas 3 and 4, lowest and second-lowest spaces on midaxillary line; areas 5 and 6, lowest and second-lowest spaces on posterior axillary line) were sonographically measured in 466 patients (214 men, 252 women; mean age, 53.0 years) after an abdominal sonographic examination. Demographic factors and the presence or absence of chronic liver disease were evaluated by multivariate analysis to investigate which factors influence intercostal width. The width of the intercostal space was 19.7 ± 3.7 mm (range, 9-33 mm) at area 1, 18.3 ± 3.4 mm (range, 9-33 mm) at area 2, 17.4 ± 4.0 mm (range, 7-33 mm) at area 3, 15.4 ± 3.5 mm (range, 5-26 mm) at area 4, 17.2 ± 3.7 mm (range, 7-28 mm) at area 5, and 14.5 ± 3.6 mm (range, 4-26 mm) at area 6. The corresponding widths of the ribs were 15.2 ± 2.3 mm (range, 8-22 mm), 14.5 ± 2.3 mm (range, 9-22 mm), 13.2 ± 2.0 mm (range, 9-20), 14.3 ± 2.2 mm (range, 9-20 mm), 15.0 ± 2.2 mm (range, 10-22 mm), and 15.1 ± 2.3 mm (range, 8-21 mm). Only female sex was significantly associated with the narrower intercostal width at areas 1, 2, 3, and 5 (regression coefficient, 1.124-1.885; p = 0.01-0.04). There was substantial variation in the widths of the intercostal spaces of the right inferior rib cage such that the anterior and inferior aspects of the intercostal space were relatively wider. Women had significantly narrower intercostal spaces than men.

Ultraviolet photometry from the orbiting astronomical observatory. XVI - The stellar Lyman-alpha absorption line

NASA Technical Reports Server (NTRS)

Savage, B. D.; Panek, R. J.

1974-01-01

The stellar Lyman-alpha line at 1216 A was observed in 29 lightly reddened stars of spectral type B2.5 to B9 by a far-UV spectrophotometer on OAO-2. The equivalent widths obtained range from 15 A at type B2.5 to 65 A at type B8; in the late-B stars, the L-alpha line removes 2 to 3% of the total stellar flux. In this sampling, the strength of the L-alpha line correlates well with measures of the Balmer discontinuity and Balmer line strengths; luminosity classification does not seem to affect the line strength. The observed line widths also agree with the predictions of Mihala's grid of non-LTE model atmospheres. In some cases, the L-alpha line influences the interstellar column densities reported in the interstellar OAO-2 L-alpha survey. Hence, these data toward lightly reddened B2 and B1.5 stars should be regarded as upper limits only.

Shift measurements of the stark-broadened ionized helium lines at 1640 and 1215 angstrom. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Vanzandt, J. R.

1976-01-01

Time-resolved measurements were made of the shifts of the ionized helium lines at 1,640 A (n = 3 approaches 2) and 1,215 A (n = 4 approaches 2), and of the Stark profile of the 1,215 A wavelength line. An electromagnetic shock tube was used as a light source. The plasma conditions corresponded to electron temperatures of approximately 3.5 eV and electron densities of 0.8 to 1.8 x 10 to the 17th power/cubic cm. The measured shifts fell between two previous estimates of plasma polarization shifts. The measured Stark width of the 1,215 A wavelength line was up to 30% greater than the theoretical width.

Photometric properties of stars clusters with young or mixed age stellar populations

NASA Astrophysics Data System (ADS)

Mollá, M.; García-Vargas, M. L.; Martín-Manjón, M. L.

2013-05-01

The main goal of this work is to present and discuss the synthetic photometrical properties of stellar clusters resulting from the PopStar code. Colors in Johnson and SDSS systems, Hα and Hβ luminosities and equivalent widths, and ionizing region size, have been computed for a wide range of metallicities Z = 0.0001, 0.0004, 0.004,0.008,0.02 and 0.05, and ages, from 0.1 Myr to 20 Gyr in Mollá, Garc{í}a-Vargas, & Bressan (2009, MNRAS, 398, 451). Emission lines are shown in Mart{í}n-Manj{ó}n et al. (2010, MNRAS, 403, 2012). Now we calculate colors with the emission lines contribution to the broad band color, so colors include stellar and nebular components, plus the emission lines following the evolution of the cluster and the region geometry in a consistent way. We compare the Single Stellar Populations contaminated and uncontaminated colors (in both Johnson and SDSS systems) and show the importance of emission lines contribution when photometry is used as a tool to characterize stellar populations. With these models we may determine the physical properties of young ionizing clusters when only photometrical observations are available and these correspond to the isolated star forming regions, subtracted the contribution of the underlying population In most cases, however, the ionizing population is usually embedded in a large and complex system, and the observed photometrical properties are the result of the combination of both the young star-forming burst and the host-underlying older population. The second objective of our work is therefore to provide a grid of models for nearby galaxies able to interpret mixed regions where the separation of young and old population is not possible or reliable enough. We obtain a set of PopStar Spectral Energy Distributions (available at PopStar site and also in VO) and derived colors for mixed populations where an underlying host population is combined in different mass ratios with a recent, metal-rich ionizing burst. These colors, together with other photometrical parameters, like Hα radius of the ionized region, and Balmer lines equivalent width and luminosity allow to infer the physical properties of star-forming regions without any spectroscopic information. For details and a complete set of tables and figures see Mollá, García-Vargas, & Martín-Manjón (2012, MNRAS, submitted).

An investigation into a micro-sized droplet impinging on a surface with sharp wettability contrast

NASA Astrophysics Data System (ADS)

Lim, C. Y.; Lam, Y. C.

2014-10-01

An experimental investigation was conducted into a micro-sized droplet jetted onto a surface with sharp wettability contrast. The dynamics of micro-sized droplet impingement on a sharp wettability contrast surface, which is critical in inkjet printing technology, has not been investigated in the literature. Hydrophilic lines with line widths ranging from 27 to 53 µm, and contact angle ranging from 17° to 77°, were patterned on a hydrophobic surface with a contact angle of 107°. Water droplets with a diameter of 81 µm were impinged at various offset distances from the centre of the hydrophilic line. The evolution of the droplet upon impingement can be divided into three distinct phases, namely the kinematic phase, the translating phase where the droplet moves towards the centre of the hydrophilic line, and the conforming phase where the droplet spreads along the line. The key parameters affecting the conformability of the droplet to the hydrophilic line pattern are the ratio of the line width to the initial droplet diameter and the contact angle of the hydrophilic line. The droplet will only conform completely to the hydrophilic pattern if the line width is not overly small relative to the droplet and the contact angle of the hydrophilic line is sufficiently low. The impact offset distance does not affect the final shape and final location of the droplet, as long as part of the droplet touches the hydrophilic line upon impingement. This process has a significant impact on inkjet printing technology as high accuracy of inkjet droplet deposition and shape control can be achieved through wettability patterning.

Cyclotron resonance in HgTe/CdTe-based heterostructures in high magnetic fields

PubMed Central

2012-01-01

Cyclotron resonance study of HgTe/CdTe-based quantum wells with both inverted and normal band structures in quantizing magnetic fields was performed. In semimetallic HgTe quantum wells with inverted band structure, a hole cyclotron resonance line was observed for the first time. In the samples with normal band structure, interband transitions were observed with wide line width due to quantum well width fluctuations. In all samples, impurity-related magnetoabsorption lines were revealed. The obtained results were interpreted within the Kane 8·8 model, the valence band offset of CdTe and HgTe, and the Kane parameter EP being adjusted. PMID:23013642

EUV observations of quiescent prominences from Skylab

NASA Technical Reports Server (NTRS)

Moe, O. K.; Cook, J. W.; Mango, S. A.

1979-01-01

Measurements of line intensities and line widths for three quiescent prominences observed with Naval Research Laboratory slit spectrograph on ATM/Skylab are reported. The wavelengths of the observed lines cover the range 1175 A to 1960 A. The measured intensities have been calibrated to within approximately a factor 2 and are average intensities over a 2 arcsec by 60 arcsec slit. Nonthermal velocities from the measured line widths are derived. The nonthermal velocity is found to increase with temperature in the prominence transition zone. Electron densities and pressures are derived from density sensitive line ratios. Electron pressures for two of the prominences are found to lie in the range 0.04-0.08 dyn/sq cm, while values for the third and most intense and active of the three prominences are in the range 0.07-0.22 dyn/sq cm.

Single mode, broad-waveguide ARROW-type semiconductor diode lasers

NASA Astrophysics Data System (ADS)

Al-Muhanna, Abdulrahman Ali

A broad transverse waveguide (low confinement) concept is used to achieve a record-high spatially incoherent cw output power of 11W for InGaAs active devices (λ = 0.97 μm) from 100μm wide-stripe and 2mm-long devices with low internal loss, α1 = 1cm-1, and high characteristic temperatures, T0 = 210K, and T1 = 1800K. A detailed above-threshold analysis reveals that reduction in gain spatial hole burning (GSHB) is possible in ARROW-type structures by using a low transverse confinement factor; consequently, a wider ARROW-core can be utilized. By incorporating both a broad-waveguide concept as well as an asymmetric structure in the transverse direction, and an ARROW-type structure in the lateral direction, a novel single-spatial mode diode laser with improved performance is obtained. Devices with low transverse confinement factor (Γ ~ 1%) and a core-region width of 7.8 μm achieved 510mW single-spatial mode pulsed output power (λ = 0.946 μm) with a full- width at half-maximum (FWHM) of the lateral far-field pattern of 4.7°.

A measurement of the width and shift of the Fe I 3719.94 A line broadened by helium. [for stellar atmosphere studies

NASA Technical Reports Server (NTRS)

Driver, R. D.; Lombardi, G.

1977-01-01

Results are reported for measurements of the widths and shifts of the overlapping helium-broadened profiles of the Fe I absorption lines at 3719.94 and 3722.56 A, which were performed in a ballistic piston compressor using a saturated solution of FeCl3 in ethanol. It is found that at 4000 K, the 3719.94-A line has a gamma/n (FWHM) value of approximately 5.2 billionths rad/sec per cu cm, the blue shift of this line corresponds to a beta/n value of about 0.49 billionth rad/sec per cu cm, and the 3722.56-A line has the same values. These results are compared with previous experimental determinations and with theoretical calculations of neutral-line broadening for the Fe I lines. The significance of these measurements with respect to the solar spectrum and cool DG white dwarfs is discussed.

Electroreflectance spectra from multiple InGaN/GaN quantum wells in the nonuniform electric field of a p–n junction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avakyants, L. P.; Aslanyan, A. E.; Bokov, P. Yu., E-mail: pavel-bokov@physics.msu.ru

A line at E = 2.77 eV (with a width of Γ = 88 meV) related to interband transitions in the region of multiple quantum wells in the active region is detected in the electroreflectance spectra of the GaN/InGaN/AlGaN heterostructure. As the modulation bias is reduced from 2.9 to 0.4 V, the above line is split into two lines with energies of E{sub 1} = 2.55 eV and E{sub 2} = 2.75 eV and widths of Γ{sub 1} = 66 meV and Γ{sub 2} = 74 meV, respectively. The smaller widths of separate lines indicate that these lines are causedmore » by interband transitions in particular quantum wells within the active region. The difference between the interband transition energies E{sub 1} and E{sub 2} in identical quantum wells in the active region is related to the fact that the quantum wells are in an inhomogeneous electric field of the p–n junction. The magnitudes of the electric-field strengths in particular quantum wells in the active region of the heterostructure are estimated to be 1.6 and 2.2 MV/cm.« less

Spectroscopic and thermodynamic properties of molecular hydrogen dissolved in water at pressures up to 200 MPa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borysow, Jacek, E-mail: jborysow@mtu.edu; Rosso, Leonardo del; Celli, Milva

2014-04-28

We have measured the Raman Q-branch of hydrogen in a solution with water at a temperature of about 280 K and at pressures from 20 to 200 MPa. From a least-mean-square fitting analysis of the broad Raman Q-branch, we isolated the contributions from the four lowest individual roto-vibrational lines. The vibrational lines were narrower than the pure rotational Raman lines of hydrogen dissolved in water measured previously, but significantly larger than in the gas. The separations between these lines were found to be significantly smaller than in gaseous hydrogen and their widths were slightly increasing with pressure. The lines weremore » narrowing with increasing rotational quantum number. The Raman frequencies of all roto-vibrational lines were approaching the values of gas phase hydrogen with increasing pressure. Additionally, from the comparison of the integrated intensity signal of Q-branch of hydrogen to the integrated Raman signal of the water bending mode, we have obtained the concentration of hydrogen in a solution with water along the 280 K isotherm. Hydrogen solubility increases slowly with pressure, and no deviation from a smooth behaviour was observed, even reaching thermodynamic conditions very close to the transition to the stable hydrogen hydrate. The analysis of the relative hydrogen concentration in solution on the basis of a simple thermodynamic model has allowed us to obtain the molar volume for the hydrogen gas/water solution. Interestingly, the volume relative to one hydrogen molecule in solution does not decrease with pressure and, at high pressure, is larger than the volume pertinent to one molecule of water. This is in favour of the theory of hydrophobic solvation, for which a larger and more stable structure of the water molecules is expected around a solute molecule.« less

Spectroscopic and thermodynamic properties of molecular hydrogen dissolved in water at pressures up to 200 MPa.

PubMed

Borysow, Jacek; del Rosso, Leonardo; Celli, Milva; Moraldi, Massimo; Ulivi, Lorenzo

2014-04-28

We have measured the Raman Q-branch of hydrogen in a solution with water at a temperature of about 280 K and at pressures from 20 to 200 MPa. From a least-mean-square fitting analysis of the broad Raman Q-branch, we isolated the contributions from the four lowest individual roto-vibrational lines. The vibrational lines were narrower than the pure rotational Raman lines of hydrogen dissolved in water measured previously, but significantly larger than in the gas. The separations between these lines were found to be significantly smaller than in gaseous hydrogen and their widths were slightly increasing with pressure. The lines were narrowing with increasing rotational quantum number. The Raman frequencies of all roto-vibrational lines were approaching the values of gas phase hydrogen with increasing pressure. Additionally, from the comparison of the integrated intensity signal of Q-branch of hydrogen to the integrated Raman signal of the water bending mode, we have obtained the concentration of hydrogen in a solution with water along the 280 K isotherm. Hydrogen solubility increases slowly with pressure, and no deviation from a smooth behaviour was observed, even reaching thermodynamic conditions very close to the transition to the stable hydrogen hydrate. The analysis of the relative hydrogen concentration in solution on the basis of a simple thermodynamic model has allowed us to obtain the molar volume for the hydrogen gas/water solution. Interestingly, the volume relative to one hydrogen molecule in solution does not decrease with pressure and, at high pressure, is larger than the volume pertinent to one molecule of water. This is in favour of the theory of hydrophobic solvation, for which a larger and more stable structure of the water molecules is expected around a solute molecule.

Spectroscopic and thermodynamic properties of molecular hydrogen dissolved in water at pressures up to 200 MPa

NASA Astrophysics Data System (ADS)

Borysow, Jacek; del Rosso, Leonardo; Celli, Milva; Moraldi, Massimo; Ulivi, Lorenzo

2014-04-01

We have measured the Raman Q-branch of hydrogen in a solution with water at a temperature of about 280 K and at pressures from 20 to 200 MPa. From a least-mean-square fitting analysis of the broad Raman Q-branch, we isolated the contributions from the four lowest individual roto-vibrational lines. The vibrational lines were narrower than the pure rotational Raman lines of hydrogen dissolved in water measured previously, but significantly larger than in the gas. The separations between these lines were found to be significantly smaller than in gaseous hydrogen and their widths were slightly increasing with pressure. The lines were narrowing with increasing rotational quantum number. The Raman frequencies of all roto-vibrational lines were approaching the values of gas phase hydrogen with increasing pressure. Additionally, from the comparison of the integrated intensity signal of Q-branch of hydrogen to the integrated Raman signal of the water bending mode, we have obtained the concentration of hydrogen in a solution with water along the 280 K isotherm. Hydrogen solubility increases slowly with pressure, and no deviation from a smooth behaviour was observed, even reaching thermodynamic conditions very close to the transition to the stable hydrogen hydrate. The analysis of the relative hydrogen concentration in solution on the basis of a simple thermodynamic model has allowed us to obtain the molar volume for the hydrogen gas/water solution. Interestingly, the volume relative to one hydrogen molecule in solution does not decrease with pressure and, at high pressure, is larger than the volume pertinent to one molecule of water. This is in favour of the theory of hydrophobic solvation, for which a larger and more stable structure of the water molecules is expected around a solute molecule.

Dipole-dipole resonance line shapes in a cold Rydberg gas

NASA Astrophysics Data System (ADS)

Richards, B. G.; Jones, R. R.

2016-04-01

We have explored the dipole-dipole mediated, resonant energy transfer reaction, 32 p3 /2+32 p3 /2→32 s +33 s , in an ensemble of cold 85Rb Rydberg atoms. Stark tuning is employed to measure the population transfer probability as a function of the total electronic energy difference between the initial and final atom-pair states over a range of Rydberg densities, 2 ×108≤ρ ≤3 ×109 cm-3. The observed line shapes provide information on the role of beyond nearest-neighbor interactions, the range of Rydberg atom separations, and the electric field inhomogeneity in the sample. The widths of the resonance line shapes increase approximately linearly with the Rydberg density and are only a factor of 2 larger than expected for two-body, nearest-neighbor interactions alone. These results are in agreement with the prediction [B. Sun and F. Robicheaux, Phys. Rev. A 78, 040701(R) (2008), 10.1103/PhysRevA.78.040701] that beyond nearest-neighbor exchange interactions should not influence the population transfer process to the degree once thought. At low densities, Gaussian rather than Lorentzian line shapes are observed due to electric field inhomogeneities, allowing us to set an upper limit for the field variation across the Rydberg sample. At higher densities, non-Lorentzian, cusplike line shapes characterized by sharp central peaks and broad wings reflect the random distribution of interatomic distances within the magneto-optical trap (MOT). These line shapes are well reproduced by an analytic expression derived from a nearest-neighbor interaction model and may serve as a useful fingerprint for characterizing the position correlation function for atoms within the MOT.

Saw-tooth refractive x-ray optics with sub-micron resolution

NASA Astrophysics Data System (ADS)

Cederstrom, Bjorn; Ribbing, Carolina; Lundqvist, Mats

2002-11-01

Saw-tooth refractive x-ray lenses have been used to focus a synchrotron beam to sub-μm line width. These lenses are free from spherical aberration and work in analogy with 1-D focusing parabolic compound refractive lenses. However, the focal length can be varied by a simple mechanical procedure. Silicon lenses were fabricated by wet anisotropic etching, and epoxy replicas were molded from the silicon masters. Theses lenses provided 1-D intensity gains up to a factor of 40 and the smallest focal line width was 0.74 μm, very close to the theoretical expectation. Two crossed lenses were put in series to obtain 2-D focusing and the 80 μm by 275 μm source was imaged to 1.0 μm by 5.4 μm. Beryllium lenses were fabricated using conventional computer-controlled milling. The focal line width was 1.7 μm, nearly 3 times larger than predicted by theory. This can be attributed to large surface roughness and a bent lens shape.

Measurements of resonant scattering in the Perseus cluster core with Hitomi SXS

NASA Astrophysics Data System (ADS)

Sato, K.; Zhuravleva, I.

2017-10-01

Hitomi (ASTRO-H) SXS allows us to investigate fine structures of emission lines in extended X-ray sources for the first time. Thanks to its high energy resolution of 5 eV at 6 keV in orbit, Hitomi SXS finds a quiescent atmosphere in the Intra cluster medium of the Perseus cluster core where the gas has a line-of-sight velocity dispersion below 200 km/sec from the line width in the spectral analysis (Hitomi collaboration, Nature, 2016). The resonant scattering is also important to measure the gas velocity as a complementary probe of the direct measurement from the line width. Particularly in the cluster core, resonant scattering should be taken into account when inferring physical properties from line intensities because the optical depth of the He-alpha resonant line is expected to be larger than 1. The observed line flux ratio of Fe XXV He-α resonant to forbidden lines is found to be lower in the cluster core when compared to the outer region, consistent with resonant scattering of the resonant line and also in support of the low turbulent velocity.

Rotational Dynamics of the Methyl Radical in Superfluid 4He Nanodroplets

DOE PAGES

Morrison, Alexander M.; Raston, Paul L.; Douberly, Gary E.

2012-12-07

Here, we report the ro-vibrational spectrum of the ν 3(e') band of the methyl radical (CH 3) solvated in superfluid 4He nanodroplets. Five allowed transitions produce population in the N K = 0 0, 1 1, 1 0, 2 2 and 2 0 rotational levels. The observed transitions exhibit variable Lorentzian line shapes, consistent with state specific homogeneous broadening effects. Population relaxation of the 00 and 11 levels is only allowed through vibrationally inelastic decay channels, and the PP 1(1) and RR 0(0) transitions accessing these levels have 4.12(1) and 4.66(1) GHz full-width at half-maximum line widths, respectively. The linemore » widths of the PR 1(1) and RR 1(1) transitions are comparatively broader (8.6(1) and 57.0(6) GHz, respectively), consistent with rotational relaxation of the 2 0 and 2 2 levels within the vibrationally excited manifold. The nuclear spin symmetry allowed rotational relaxation channel for the excited 1 0 level has an energy difference similar to those associated with the 2 0 and 2 2 levels. However, the PQ 1(1) transition that accesses the 1 0 level is 2.3 and 15.1 times narrower than the PR 1(1) and RR 1(1) lines, respectively. The relative line widths of these transitions are rationalized in terms of the anisotropy in the He-CH 3 potential energy surface, which couples the molecule rotation to the collective modes of the droplet.« less

Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey

DOE PAGES

Rumbaugh, N.

2018-02-21

Here, we perform a systematic search for long-term extreme variability quasars (EVQs) in the overlapping Sloan Digital Sky Survey (SDSS) and 3-Year Dark Energy Survey (DES) imaging, which provide light curves spanning more than 15 years. We also identified 1000 EVQs with a maximum g band magnitude change of more than 1 mag over this period, about 10% of all quasars searched. The EVQs have L bol 10 45 - 10 47 erg s -1 and L=L Edd 0:01-1. Accounting for selection effects, we estimate an intrinsic EVQ fraction of 30-50% among all g.22 quasars over a baseline of 15more » years. These EVQs are good candidates for so-called “changing-look quasars”, where a spectral transition between the two types of quasars (broad-line and narrow-line) is observed between the dim and bright states. We performed detailed multi-wavelength, spectral and variability analyses for the EVQs and compared to their parent quasar sample. We found that EVQs are distinct from a control sample of quasars matched in redshift and optical luminosity: (1) their UV broad emission lines have larger equivalent widths; (2) their Eddington ratios are systematically lower; and (3) they are more variable on all timescales. The intrinsic difference in quasar properties for EVQs suggest that internal processes associated with accretion are the main driver for the observed extreme long-term variability. In spit of their different properties, EVQs seem to be in the tail of a continuous distribution of quasar properties, rather than standing out as a distinct population. We speculate that EVQs are normal quasars accreting at relatively low accretion rates, where the accretion flow is more likely to experience instabilities that drive the factor of few changes in flux on multi-year timescales.« less

Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rumbaugh, N.

Here, we perform a systematic search for long-term extreme variability quasars (EVQs) in the overlapping Sloan Digital Sky Survey (SDSS) and 3-Year Dark Energy Survey (DES) imaging, which provide light curves spanning more than 15 years. We also identified 1000 EVQs with a maximum g band magnitude change of more than 1 mag over this period, about 10% of all quasars searched. The EVQs have L bol 10 45 - 10 47 erg s -1 and L=L Edd 0:01-1. Accounting for selection effects, we estimate an intrinsic EVQ fraction of 30-50% among all g.22 quasars over a baseline of 15more » years. These EVQs are good candidates for so-called “changing-look quasars”, where a spectral transition between the two types of quasars (broad-line and narrow-line) is observed between the dim and bright states. We performed detailed multi-wavelength, spectral and variability analyses for the EVQs and compared to their parent quasar sample. We found that EVQs are distinct from a control sample of quasars matched in redshift and optical luminosity: (1) their UV broad emission lines have larger equivalent widths; (2) their Eddington ratios are systematically lower; and (3) they are more variable on all timescales. The intrinsic difference in quasar properties for EVQs suggest that internal processes associated with accretion are the main driver for the observed extreme long-term variability. In spit of their different properties, EVQs seem to be in the tail of a continuous distribution of quasar properties, rather than standing out as a distinct population. We speculate that EVQs are normal quasars accreting at relatively low accretion rates, where the accretion flow is more likely to experience instabilities that drive the factor of few changes in flux on multi-year timescales.« less

The structure of galactic HI in directions of low total column density

NASA Technical Reports Server (NTRS)

Lockman, F. J.; Jahoda, K.; Mccammon, D.

1985-01-01

A detailed 21 cm study of areas of that have the smallest known amount of HI in the northern sky was performed. These observations were corrected for stray radiation. The region of main interest, around alpha = 10(h)45(m), delta = 57 deg 20', has a minimium N(HI) of 4.5 x 10 to the 19th power/sq cm. Spectra taken at 21' resolution over a field 4 x 3 deg in this direction show up to four HI line components. Two, near 0 and -50 km/s, are ubiquitous. There is also a narrow component at -10 km/s attributable to a diffuse cloud covering half of the field, and scattered patches of HI at v -100 km/s. the low and intermediate velocity components have a broad line width and are so smoothly distributed across the region that it is unlikely that they contain significant unresolved angular structure. Eight other low column density directions were also observed. Their spectra typically have several components, but the total column density is always 7 x 10 to the 19th power/sq cm and changes smoothly along a 2 deg strip. Half of the directions show narrow lines arising from weak diffuse HI clouds that contain 0.5 to 3.0 x 10 to the 19th power/sq cm.

Long-term spectroscopic monitoring of the Luminous Blue Variable AG Carinae

NASA Astrophysics Data System (ADS)

Stahl, O.; Jankovics, I.; Kovács, J.; Wolf, B.; Schmutz, W.; Kaufer, A.; Rivinius, Th.; Szeifert, Th.

2001-08-01

We have extensively monitored the Luminous Blue Variable AG Car (HD 94910) spectroscopically. Our data cover the years 1989 to 1999. In this period, the star underwent almost a full S Dor cycle from visual minimum to maximum and back. Over several seasons, up to four months of almost daily spectra are available. Our data cover most of the visual spectral range with a high spectral resolution (lambda /Delta lambda ~ 20 000). This allows us to investigate the variability in many lines on time scales from days to years. The strongest variability occurs on a time scale of years. Qualitatively, the variations can be understood as changes of the effective temperature and radius, which are in phase with the optical light curve. Quantitatively, there are several interesting deviations from this behaviour, however. The Balmer lines show P Cygni profiles and have their maximum strength (both in equivalent width and line flux) after the peak of the optical light curve, at the descending branch of the light curve. The line-width during maximum phase is smaller than during minimum, but it has a local maximum close to the peak of the visual light curve. We derive mass-loss rates over the cycle from the Hα line and find the highest mass loss rates (log dot {M}/({M}_sun yr-1) ~ -3.8, about a factor of five higher than in the minimum, where we find log dot {M}/({M}_sun yr-1) ~ -4.5) after the visual maximum. Line-splitting is very commonly observed, especially on the rise to maximum and on the descending branch from maximum. The components are very long-lived (years) and are probably unrelated to similar-looking line-splitting events in normal supergiants. Small apparent accelerations of the components are observed. The change in radial velocity could be due to successive narrowing of the components, with the absorption disappearing at small expansion velocities first. In general, the line-splitting is more likely the result of missing absorption at intermediate velocities than of excess absorption at the velocities of the components. The HeI lines and other lines which form deep in the atmosphere show the most peculiar variations. The HeI lines show a central absorption with variable blue- and red-shifted emission components. Due to the variations of the emission components, the HeI lines can change their line profile from a normal P Cyg profile to an inverse P Cyg-profile or double-peak emission. In addition, very broad (+/-1500 km s-1) emission wings are seen at the strongest HeI lines of AG Car. At some phases, a blue-shifted absorption is also present. The central absorption of the HeI lines is blue-shifted before and red-shifted after maximum. Possibly, we directly see the expansion and contraction of the photosphere. If this explanation is correct, the velocity of the continuum-forming layer is not dominated by expansion but is only slightly oscillating around the systemic velocity. Based on observations collected at the European Southern Observatory at La Silla, Chile.

VizieR Online Data Catalog: Broad Hβ emission line in 102 Seyfert galaxies (Runco+, 2016)

NASA Astrophysics Data System (ADS)

Runco, J. N.; Cosens, M.; Bennert, V. N.; Scott, B.; Komossa, S.; Malkan, M. A.; Lazarova, M. S.; Auger, M. W.; Treu, T.; Park, D.

2018-02-01

A sample of 102 local (0.02=

Voigt deconvolution method and its applications to pure oxygen absorption spectrum at 1270 nm band.

PubMed

Al-Jalali, Muhammad A; Aljghami, Issam F; Mahzia, Yahia M

2016-03-15

Experimental spectral lines of pure oxygen at 1270 nm band were analyzed by Voigt deconvolution method. The method gave a total Voigt profile, which arises from two overlapping bands. Deconvolution of total Voigt profile leads to two Voigt profiles, the first as a result of O2 dimol at 1264 nm band envelope, and the second from O2 monomer at 1268 nm band envelope. In addition, Voigt profile itself is the convolution of Lorentzian and Gaussian distributions. Competition between thermal and collisional effects was clearly observed through competition between Gaussian and Lorentzian width for each band envelope. Voigt full width at half-maximum height (Voigt FWHM) for each line, and the width ratio between Lorentzian and Gaussian width (ΓLΓG(-1)) have been investigated. The following applied pressures were at 1, 2, 3, 4, 5, and 8 bar, while the temperatures were at 298 K, 323 K, 348 K, and 373 K range. Copyright © 2015 Elsevier B.V. All rights reserved.

Double-peaked broad line emission from the LINER nucleus of NGC 1097

NASA Technical Reports Server (NTRS)

Storchi-Bergmann, Thaisa; Baldwin, Jack A.; Wilson, Andrew S.

1993-01-01

We report the recent appearance of a very broad component in the H-alpha and H-beta emission lines of the weakly active nucleus of the Sersic-Pastoriza galaxy NGC 1097. The FWZI of the broad component is about 21,000 km/s, and its profile is double-peaked; the presence of a blue, featureless continuum in the nucleus is also suggested. The broad component was first observed in H-alpha in November 2, 1991, and confirmed 11 months later. The H-alpha profile and flux did not change in this time interval. Comparison with previously published spectral data indicates that the broad lines have only recently appeared. Together with the relatively high X-ray luminosity and the compact nuclear radio source, our results characterize the presence of a Seyfert 1 nucleus in a galaxy which had previously shown only LINER characteristics. Obscuring material along our line of sight to the nucleus appears to have recently cleared, permitting a direct view of the active nucleus. We discuss two possible structures for the broad line region, biconical outflow and an accretion disk, that could give rise to the observed profile.

Kinetic-Energy Distribution of D(2p) Atoms from Analysis of the D Lyman-Alpha Line Profile

NASA Technical Reports Server (NTRS)

Ciocca, M.; Ajello, Joseph M.; Liu, Xianming; Maki, Justin

1997-01-01

The kinetic-energy distribution of D(2p) atoms resulting from electron-impact dissociation of D2 has been measured. A high-resolution vacuum ultraviolet spectrometer was employed for the first measurement of the D Lyman-alpha (D L(alpha)) emission line profiles at 20- and 100-eV excitation energies. Analysis of the deconvoluted line profile of D L(alpha) at 100 eV reveals the existence of a narrow line central peak of 29+/-2 mA full width at half maximum and a broad pedestal wing structure about 190 mA wide. The wings of the line can be used to determine the fast atom distribution. The wings of D L(alpha) arise from dissociative excitation of a series of doubly excited states that cross the Franck-Condon region between 23 and 40 eV. The fast atom distribution at 100-eV electron impact energy spans the energy range from 1 to 10 eV with a peak value near 6 eV. Slow D(2p) atoms characterized by a distribution function with peak energy near 100 meV produce the central peak profile, which is nearly independent of the impact energy. The deconvoluted line profiles of the central peak at 20 eV for dissociative excitation of D2 and H2 are fitted with an analytical function for use in calibration of space flight instrumentation equipped with a D/H absorption cell. The kinetic-energy and line profile results are compared to similar measurements for H2. The absolute cross sections for the line center (slow atoms) and wings (fast atoms) and total emission line profile were measured from threshold to 400 eV. Analytical model coefficients are given for the energy dependence of the measured slow atom cross section.

Advances in 7xx-nm fiber-coupled modules with application to Tm fiber laser pumping and DPAL (Conference Presentation)

NASA Astrophysics Data System (ADS)

Patterson, Steven G.; Guiney, Tina; Stapleton, Dean; Braker, Joseph; Alegria, Kim; Irwin, David A.; Ebert, Christopher

2017-02-01

DILAS has leveraged its industry-leading work in manufacturing low SWaP fiber-coupled modules extending the wavelength range to 793nm for Tm fiber laser pumping. Ideal for medical, industrial and military applications, modules spanning from single emitter-based 9W to TBar-based 200W of 793nm pump power will be discussed. The highlight is a lightweight module capable of <200W of 793nm pump power out of a package weighing < 400 grams. In addition, other modules spanning from single emitter-based 9W to TBar-based 200W of 793nm pump power will be presented. In addition, advances in DPAL modules, emitting at the technologically important wavelengths near 766nm and 780nm, will be detailed. Highlights include a fully microprocessor controlled fiber-coupled module that produces greater than 400W from a 600 micron core fiber and a line width of only 56.3pm. The micro-processor permits the automated center wavelength and line width tuning of the output over a range of output powers while retaining excellent line center and line width stability over time.

H2-broadening, shifting and mixing coefficients of the doublets in the ν2 and ν4 bands of PH3 at room temperature

NASA Astrophysics Data System (ADS)

Salem, Jamel; Blanquet, Ghislain; Lepère, Muriel; Younes, Rached ben

2018-05-01

The broadening, shifting and mixing coefficients of the doublet spectral lines in the ν2 and ν4 bands of PH3 perturbed by H2 have been determined at room temperature. Indeed, the collisional spectroscopic parameters: intensities, line widths, line shifts and line mixing parameters, are all grouped together in the collisional relaxation matrix. To analyse the collisional process and physical effects on spectra of phosphine (PH3), we have used the measurements carried out using a tunable diode-laser spectrometer in the ν2 and ν4 bands of PH3 perturbed by hydrogen (H2) at room temperature. The recorded spectra are fitted by the Voigt profile and the speed-dependent uncorrelated hard collision model of Rautian and Sobelman. These profiles are developed in the studies of isolated lines and are modified to account for the line mixing effects in the overlapping lines. The line widths, line shifts and line mixing parameters are given for six A1 and A2 doublet lines with quantum numbers K = 3n, (n = 1, 2, …) and overlapped by collisional broadening at pressures of less than 50 mbar.

Line parameters for CO2 broadening in the ν2 band of HD16O

NASA Astrophysics Data System (ADS)

Devi, V. Malathy; Benner, D. Chris; Sung, Keeyoon; Crawford, Timothy J.; Gamache, Robert R.; Renaud, Candice L.; Smith, Mary Ann H.; Mantz, Arlan W.; Villanueva, Geronimo L.

2017-01-01

CO2-rich planetary atmospheres such as those of Mars and Venus require accurate knowledge of CO2 broadened HDO half-width coefficients and their temperature dependence exponents for reliable abundance determination. Although a few calculated line lists have recently been published on HDO-CO2 line shapes and their temperature dependences, laboratory measurements of those parameters are thus far non-existent. In this work, we report the first measurements of CO2-broadened half-width and pressure-shift coefficients and their temperature dependences for over 220 transitions in the ν2 band. First measurements of self-broadened half-width and self-shift coefficients at room temperature are also obtained for majority of these transitions. In addition, the first experimental determination of collisional line mixing has been reported for 11 transition pairs for HDO-CO2 and HDO-HDO systems. These results were obtained by analyzing ten high-resolution spectra of HDO and HDO-CO2 mixtures at various sample temperatures and pressures recorded with the Bruker IFS-125HR Fourier transform spectrometer at the Jet Propulsion Laboratory (JPL). Two coolable absorption cells with path lengths of 20.38 cm and 20.941 m were used to record the spectra. The various line parameters were retrieved by fitting all ten spectra simultaneously using a multispectrum nonlinear least squares fitting algorithm. The HDO transitions in the 1100-4100 cm-1 range were extracted from the HITRAN2012 database. For the ν2 and 2ν2 -ν2 bands there were 2245 and 435 transitions, respectively. Modified Complex Robert-Bonamy formalism (MCRB) calculations were made for the half-width coefficients, their temperature dependence and the pressure shift coefficients for the HDO-CO2 and HDO-HDO collision systems. MCRB calculations are compared with the measured values.

Theoretical Studies of N2-broadened Half-widths of H2O Lines Involving High j States

NASA Technical Reports Server (NTRS)

Ma, Q.; Tipping, R. H.; Lavrentieva, N. N.

2012-01-01

Based on the properties of the energy levels and wave functions of H2O states, one can categorize H2O lines into individually defined groups such that within the same group, the energy levels and the wave functions associated with two paired lines have an identity property while those associated with different pairs have a similarity property. Meanwhile, by thoroughly analyzing processes used to calculate N2-broadened half-widths, it was found that the 'Fourier series' of W(sup a)(sub L(sub 1))(sub K(sub 1))(sub K(sub 1)) (t; j(sub f) T(sub f) and W(sup a)(sub L(sub 1))(sub K(sub 1))(sub K(sub 1)) (t; j(sub i) T(sub i), and a factor P(sub 222) (j(sub f) T(sub f) j(sub i) T(sub i)) are the key items in the Robert-Bonamy formalism to distinguish contributions to ReS2(r(sub c)) among different transitions of j(sub f) T(sub f) - j(sub i). However, these items are completely determined by the energy levels and the wave functions associated with their initial and final states and they must bear the latter's features as well. Thus, it becomes obvious that for two paired lines in the same group, their calculated half-widths must be almost identical and the values associated with different pairs must vary smoothly as their ji values vary. Thus, the pair identity and the smooth variation rules are established within individual groups of lines. One can use these rules to screen half-width data listed in HITRAN and to improve the data accuracies.

Alfvén Wave Turbulence as a Coronal Heating Mechanism: Simultaneously Predicting the Heating Rate and the Wave-induced Emission Line Broadening

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oran, R.; Landi, E.; Holst, B. van der

We test the predictions of the Alfvén Wave Solar Model (AWSoM), a global wave-driven magnetohydrodynamic (MHD) model of the solar atmosphere, against high-resolution spectra emitted by the quiescent off-disk solar corona. AWSoM incorporates Alfvén wave propagation and dissipation in both closed and open magnetic field lines; turbulent dissipation is the only heating mechanism. We examine whether this mechanism is consistent with observations of coronal EUV emission by combining model results with the CHIANTI atomic database to create synthetic line-of-sight spectra, where spectral line widths depend on thermal and wave-related ion motions. This is the first time wave-induced line broadening ismore » calculated from a global model with a realistic magnetic field. We used high-resolution SUMER observations above the solar west limb between 1.04 and 1.34 R {sub ⊙} at the equator, taken in 1996 November. We obtained an AWSoM steady-state solution for the corresponding period using a synoptic magnetogram. The 3D solution revealed a pseudo-streamer structure transversing the SUMER line of sight, which contributes significantly to the emission; the modeled electron temperature and density in the pseudo-streamer are consistent with those observed. The synthetic line widths and the total line fluxes are consistent with the observations for five different ions. Further, line widths that include the contribution from the wave-induced ion motions improve the correspondence with observed spectra for all ions. We conclude that the turbulent dissipation assumed in the AWSoM model is a viable candidate for explaining coronal heating, as it is consistent with several independent measured quantities.« less

An Experimental and Theoretical Study of Nitrogen-Broadened Acetylene Lines

NASA Technical Reports Server (NTRS)

Thibault, Franck; Martinez, Raul Z.; Bermejo, Dionisio; Ivanov, Sergey V.; Buzykin, Oleg G.; Ma, Qiancheng

2014-01-01

We present experimental nitrogen-broadening coefficients derived from Voigt profiles of isotropic Raman Q-lines measured in the 2 band of acetylene (C2H2) at 150 K and 298 K, and compare them to theoretical values obtained through calculations that were carried out specifically for this work. Namely, full classical calculations based on Gordon's approach, two kinds of semi-classical calculations based on Robert Bonamy method as well as full quantum dynamical calculations were performed. All the computations employed exactly the same ab initio potential energy surface for the C2H2N2 system which is, to our knowledge, the most realistic, accurate and up-to-date one. The resulting calculated collisional half-widths are in good agreement with the experimental ones only for the full classical and quantum dynamical methods. In addition, we have performed similar calculations for IR absorption lines and compared the results to bibliographic values. Results obtained with the full classical method are again in good agreement with the available room temperature experimental data. The quantum dynamical close-coupling calculations are too time consuming to provide a complete set of values and therefore have been performed only for the R(0) line of C2H2. The broadening coefficient obtained for this line at 173 K and 297 K also compares quite well with the available experimental data. The traditional Robert Bonamy semi-classical formalism, however, strongly overestimates the values of half-width for both Qand R-lines. The refined semi-classical Robert Bonamy method, first proposed for the calculations of pressure broadening coefficients of isotropic Raman lines, is also used for IR lines. By using this improved model that takes into account effects from line coupling, the calculated semi-classical widths are significantly reduced and closer to the measured ones.

Stellar Photometric Structures of the Host Galaxies of Nearby Type 1 Active Galactic Nuclei

NASA Astrophysics Data System (ADS)

Kim, Minjin; Ho, Luis C.; Peng, Chien Y.; Barth, Aaron J.; Im, Myungshin

2017-10-01

We present detailed image analysis of rest-frame optical images of 235 low-redshift (z ≲ 0.35) Type 1 active galactic nuclei (AGNs) observed with the Hubble Space Telescope. The high-resolution images enable us to perform rigorous two-dimensional image modeling to decouple the luminous central point source from the host galaxy, which, when warranted, is further decomposed into its principal structural components (bulge, bar, and disk). In many cases, care must be taken to account for structural complexities such as spiral arms, tidal features, and overlapping or interacting companion galaxies. We employ Fourier modes to characterize the degree of asymmetry of the light distribution of the stars as a quantitative measure of morphological distortion due to interactions or mergers. We examine the dependence of the physical parameters of the host galaxies on the properties of the AGNs, namely, radio-loudness and the width of the broad emission lines. In accordance with previous studies, narrow-line (Hβ FWHM ≤ 2000 km s-1) Type 1 AGNs, in contrast to their broad-line (Hβ FWHM > 2000 km s-1) counterparts, are preferentially hosted in later-type, lower-luminosity galaxies, which have a higher incidence of pseudo-bulges, are more frequently barred, and are less morphologically disturbed. This suggests that narrow-line Type 1 AGNs experienced a more quiescent evolutionary history driven primarily by internal secular evolution instead of external dynamical perturbations. The fraction of AGN hosts showing merger signatures is larger for more luminous sources. Radio-loud AGNs generally preferentially live in earlier-type (bulge-dominated), more massive hosts, although a minority of them appear to contain a significant disk component. We do not find convincing evidence for enhanced merger signatures in the radio-loud population. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS5-26555. These data are associated with program AR-12133 and AR-12818.

Investigation on chlorosomal antenna geometries: tube, lamella and spiral-type self-aggregates.

PubMed

Linnanto, Juha M; Korppi-Tommola, Jouko E I

2008-06-01

Molecular mechanics calculations and exciton theory have been used to study pigment organization in chlorosomes of green bacteria. Single and double rod, multiple concentric rod, lamella, and Archimedean spiral macrostructures of bacteriochlorophyll c molecules were created and their spectral properties evaluated. The effects of length, width, diameter, and curvature of the macrostructures as well as orientations of monomeric transition dipole moment vectors on the spectral properties of the aggregates were studied. Calculated absorption, linear dichroism, and polarization dependent fluorescence-excitation spectra of the studied long macrostructures were practically identical, but circular dichroism spectra turned out to be very sensitive to geometry and monomeric transition dipole moment orientations of the aggregates. The simulations for long multiple rod and spiral-type macrostructures, observed in recent high-resolution electron microscopy images (Oostergetel et al., FEBS Lett 581:5435-5439, 2007) gave shapes of circular dichroism spectra observed experimentally for chlorosomes. It was shown that the ratio of total circular dichroism intensity to integrated absorption of the Q(y) transition is a good measure of degree of tubular structures in the chlorosomes. Calculations suggest that the broad Q(y) line width of chlorosomes of sulfur bacteria could be due to (1) different orientations of the transition moment vectors in multi-walled rod structures or (2) a variety of Bchl-aggregate structures in the chlorosomes.

Non-LTE, line-blanketed model atmospheres for late O- and early B-type stars

NASA Technical Reports Server (NTRS)

Grigsby, James A.; Morrison, Nancy D.; Anderson, Lawrence S.

1992-01-01

The use of non-LTE line-blanketed model atmospheres to analyze the spectra of hot stars is reported. The stars analyzed are members of clusters and associations, have spectral types in the range O9-B2 and luminosity classes in the range III-IV, have slow to moderate rotation, and are photometrically constant. Sampled line opacities of iron-group elements were incorporated in the radiative transfer solution; solar abundances were assumed. Good to excellent agreement is obtained between the computed profiles and essentially all the line profiles used to fix the model, and reliable stellar parameters are derived. The synthetic M II 5581 equivalent widths agree well with the observed ones at the low end of the temperature range studied, but, above 25,000 K, the synthetic line is generally stronger than the observed line. The behavior of the observed equivalent widths of N II, N III, C II and C III lines as a function of Teff is studied. Most of the lines show much scatter, with no consistent trend that could indicate abundance differences from star to star.

High-Resolution X-Ray Spectroscopy and Modeling of the Absorbing and Emitting Outflow in NGC 3783

NASA Astrophysics Data System (ADS)

Kaspi, Shai; Brandt, W. N.; Netzer, Hagai; George, Ian M.; Chartas, George; Behar, Ehud; Sambruna, Rita M.; Garmire, Gordon P.; Nousek, John A.

2001-06-01

The high-resolution X-ray spectrum of NGC 3783 shows several dozen absorption lines and a few emission lines from the H-like and He-like ions of O, Ne, Mg, Si, and S, as well as from Fe XVII-Fe XXIII L-shell transitions. We have reanalyzed the Chandra HETGS spectrum using better flux and wavelength calibrations, along with more robust methods. Combining several lines from each element, we clearly demonstrate the existence of the absorption lines and determine that they are blueshifted relative to the systemic velocity by -610+/-130 km s-1. We find the Ne absorption lines in the High-Energy Grating spectrum to be resolved with FWHM=840+490-360 km s-1; no other lines are resolved. The emission lines are consistent with being at the systemic velocity. We have used regions in the spectrum where no lines are expected to determine the X-ray continuum, and we model the absorption and emission lines using photoionized-plasma calculations. The model consists of two absorption components, with different covering factors, which have an order-of-magnitude difference in their ionization parameters. The two components are spherically outflowing from the active galactic nucleus, and thus contribute to both the absorption and the emission via P Cygni profiles. The model also clearly requires O VII and O VIII absorption edges. The low-ionization component of our model can plausibly produce UV absorption lines with equivalent widths consistent with those observed from NGC 3783. However, we note that this result is highly sensitive to the unobservable UV to X-ray continuum, and the available UV and X-ray observations cannot firmly establish the relationship between the UV and X-ray absorbers. We find good agreement between the Chandra spectrum and simultaneous ASCA and RXTE observations. The 1 keV deficit previously found when modeling ASCA data probably arises from iron L-shell absorption lines not included in previous models. We also set an upper limit on the FWHM of the narrow Fe Kα emission line of 3250 km s-1. This is consistent with this line originating outside the broad-line region, possibly from a torus.

Diatomic predissociation line widths

NASA Technical Reports Server (NTRS)

Child, M. S.

1973-01-01

Predissociation by rotation and curve crossing in diatomic molecules is discussed. The pattern of predissociation line widths is seen as providing a highly sensitive yardstick for the determination of unknown potential curves. In addition, the computation of such a pattern for given potential curves is considered a matter of routine, unless the predissociation happens to occur from an adiabatic potential curve. Analytic formulas are used to provide physical insight into the details of the predissociation pattern, to the extent that a direct inversion procedure is developed for determination of the repulsive potential curves for Type 1 predissociations.

Constraining sub-parsec binary supermassive black holes in quasars with multi-epoch spectroscopy. II. The population with kinematically offset broad Balmer emission lines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Xin; Shen, Yue; Bian, Fuyan

2014-07-10

A small fraction of quasars have long been known to show bulk velocity offsets (of a few hundred to thousands of km s{sup –1}) in the broad Balmer lines with respect to the systemic redshift of the host galaxy. Models to explain these offsets usually invoke broad-line region gas kinematics/asymmetry around single black holes (BHs), orbital motion of massive (∼sub-parsec (sub-pc)) binary black holes (BBHs), or recoil BHs, but single-epoch spectra are unable to distinguish between these scenarios. The line-of-sight (LOS) radial velocity (RV) shifts from long-term spectroscopic monitoring can be used to test the BBH hypothesis. We have selectedmore » a sample of 399 quasars with kinematically offset broad Hβ lines from the Sloan Digital Sky Survey (SDSS) Seventh Data Release quasar catalog, and have conducted second-epoch optical spectroscopy for 50 of them. Combined with the existing SDSS spectra, the new observations enable us to constrain the LOS RV shifts of broad Hβ lines with a rest-frame baseline of a few years to nearly a decade. While previous work focused on objects with extreme velocity offset (>10{sup 3} km s{sup –1}), we explore the parameter space with smaller (a few hundred km s{sup –1}) yet significant offsets (99.7% confidence). Using cross-correlation analysis, we detect significant (99% confidence) radial accelerations in the broad Hβ lines in 24 of the 50 objects, of ∼10-200 km s{sup –1} yr{sup –1} with a median measurement uncertainty of ∼10 km s{sup –1} yr{sup –1}, implying a high fraction of variability of the broad-line velocity on multi-year timescales. We suggest that 9 of the 24 detections are sub-pc BBH candidates, which show consistent velocity shifts independently measured from a second broad line (either Hα or Mg II) without significant changes in the broad-line profiles. Combining the results on the general quasar population studied in Paper I, we find a tentative anti-correlation between the velocity offset in the first-epoch spectrum and the average acceleration between two epochs, which could be explained by orbital phase modulation when the time separation between two epochs is a non-negligible fraction of the orbital period of the motion causing the line displacement. We discuss the implications of our results for the identification of sub-pc BBH candidates in offset-line quasars and for the constraints on their frequency and orbital parameters.« less

Vespertilionid bats control the width of their biosonar sound beam dynamically during prey pursuit

PubMed Central

Jakobsen, Lasse; Surlykke, Annemarie

2010-01-01

Animals using sound for communication emit directional signals, focusing most acoustic energy in one direction. Echolocating bats are listening for soft echoes from insects. Therefore, a directional biosonar sound beam greatly increases detection probability in the forward direction and decreases off-axis echoes. However, high directionality has context-specific disadvantages: at close range the detection space will be vastly reduced, making a broad beam favorable. Hence, a flexible system would be very advantageous. We investigated whether bats can dynamically change directionality of their biosonar during aerial pursuit of insects. We trained five Myotis daubentonii and one Eptesicus serotinus to capture tethered mealworms and recorded their echolocation signals with a multimicrophone array. The results show that the bats broaden the echolocation beam drastically in the terminal phase of prey pursuit. M. daubentonii increased the half-amplitude angle from approximately 40° to approximately 90° horizontally and from approximately 45° to more than 90° vertically. The increase in beam width is achieved by lowering the frequency by roughly one octave from approximately 55 kHz to approximately 27.5 kHz. The E. serotinus showed beam broadening remarkably similar to that of M. daubentonii. Our results demonstrate dynamic control of beam width in both species. Hence, we propose directionality as an explanation for the frequency decrease observed in the buzz of aerial hawking vespertilionid bats. We predict that future studies will reveal dynamic control of beam width in a broad range of acoustically communicating animals. PMID:20643943

Vespertilionid bats control the width of their biosonar sound beam dynamically during prey pursuit.

PubMed

Jakobsen, Lasse; Surlykke, Annemarie

2010-08-03

Animals using sound for communication emit directional signals, focusing most acoustic energy in one direction. Echolocating bats are listening for soft echoes from insects. Therefore, a directional biosonar sound beam greatly increases detection probability in the forward direction and decreases off-axis echoes. However, high directionality has context-specific disadvantages: at close range the detection space will be vastly reduced, making a broad beam favorable. Hence, a flexible system would be very advantageous. We investigated whether bats can dynamically change directionality of their biosonar during aerial pursuit of insects. We trained five Myotis daubentonii and one Eptesicus serotinus to capture tethered mealworms and recorded their echolocation signals with a multimicrophone array. The results show that the bats broaden the echolocation beam drastically in the terminal phase of prey pursuit. M. daubentonii increased the half-amplitude angle from approximately 40 degrees to approximately 90 degrees horizontally and from approximately 45 degrees to more than 90 degrees vertically. The increase in beam width is achieved by lowering the frequency by roughly one octave from approximately 55 kHz to approximately 27.5 kHz. The E. serotinus showed beam broadening remarkably similar to that of M. daubentonii. Our results demonstrate dynamic control of beam width in both species. Hence, we propose directionality as an explanation for the frequency decrease observed in the buzz of aerial hawking vespertilionid bats. We predict that future studies will reveal dynamic control of beam width in a broad range of acoustically communicating animals.

Ideal MHD stability of double transport barrier plasmas in DIII-D

NASA Astrophysics Data System (ADS)

Li, G. Q.; Wang, S. J.; Lao, L. L.; Turnbull, A. D.; Chu, M. S.; Brennan, D. P.; Groebner, R. J.; Zhao, L.

2008-01-01

The ideal MHD stability for double transport barrier (DTB or DB) plasmas with varying edge and internal barrier width and height was investigated, using the ideal MHD stability code GATO. A moderate ratio of edge transport barriers (ETB) height to internal transport barriers (ITBs) height is found to be beneficial to MHD stability and the βN is limited by global low n instabilities. For moderate ITB width DB plasmas, if the ETB is weak, the stability is limited by n = 1 (n is the toroidal mode number) global mode; whereas if the ETB is strong it is limited by intermediate-n edge peeling-ballooning modes. Broadening the ITB can improve stability if the ITB half width wi lsim 0.3. For very broad ITB width plasmas the stability is limited by stability to a low n (n > 1) global mode.

Formation of a uniform ion beam using octupole magnets for BioLEIR facility at CERN

NASA Astrophysics Data System (ADS)

Amin, T.; Barlow, R.; Ghithan, S.; Roy, G.; Schuh, S.

2018-04-01

The possibility to transform the Low Energy Ion Ring (LEIR) accelerator at CERN into a multidisciplinary, biomedical research facility (BioLEIR) was investigated based on a request from the biomedical community. BioLEIR aims to provide a unique facility with a range of fully stripped ion beams (e.g. He, Li, Be, B, C, N, O) and energies suitable for multidisciplinary biomedical, clinically-oriented research. Two horizontal and one vertical beam transport lines have been designed for transporting the extracted beam from LEIR to three experimental end-stations. The vertical beamline was designed for a maximum energy of 75 MeV/u, while the two horizontal beamlines shall deliver up to a maximum energy of 440 MeV/u. A pencil beam of 4.3 mm FWHM (Full Width Half Maximum) as well as a homogeneous broad beam of 40 × 40 mm2, with a beam homogeneity better than ±4%, are available at the first horizontal (H1) irradiation point, while only a pencil beam is available at the second horizontal (H2) and vertical (V) irradiation points. The H1 irradiation point shall be used to conduct systematic studies of the radiation effect from different ion species on cell-lines. The H1 beamline was designed to utilize two octupole magnets which transform the Gaussian beam distribution at the target location into an approximately uniformly distributed rectangular beam. In this paper, we report on the multi-particle tracking calculations performed using MAD-X software suite for the H1 beam optics to arrive at a homogeneous broad beam on target using nonlinear focusing techniques, and on those to create a Gaussian pencil beam on target by adjusting quadrupoles strengths and positions.

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.

The Host Galaxy and Central Engine of the Dwarf Active Galactic Nucleus POX 52

NASA Astrophysics Data System (ADS)

Thornton, Carol E.; Barth, Aaron J.; Ho, Luis C.; Rutledge, Robert E.; Greene, Jenny E.

2008-10-01

We present new multiwavelength observations of the dwarf Seyfert 1 galaxy POX 52 in order to investigate the properties of the host galaxy and the active nucleus and to examine the mass of its black hole, previously estimated to be ~105 M⊙. HST ACS HRC images show that the host galaxy has a dwarf elliptical morphology (MI = - 18.4 mag, Sérsic index n = 4.3) with no detected disk component or spiral structure, confirming previous results from ground-based imaging. X-ray observations from both Chandra and XMM-Newton show strong (factor of 2) variability over timescales as short as 500 s, as well as a dramatic decrease in the absorbing column density over a 9 month period. We attribute this change to a partial covering absorber, with a 94% covering fraction and NH = 58+ 8.4-9.2 × 1021 cm -2, that moved out of the line of sight in between the XMM-Newton and Chandra observations. Combining these data with observations from the VLA, Spitzer, and archival data from 2MASS and GALEX, we examine the SED of the active nucleus. Its shape is broadly similar to typical radio-quiet quasar SEDs, despite the very low bolometric luminosity of Lbol = 1.3 × 1043 ergs s-1. Finally, we compare black hole mass estimators, including methods based on X-ray variability, and optical scaling relations using the broad Hβ line width and AGN continuum luminosity, finding a range of black hole mass from all methods to be MBH = (2.2-4.2) × 105 M⊙, with an Eddington ratio of Lbol/LEdd ≈ 0.2-0.5.

Accretion Rate and the Physical Nature of Unobscured Active Galaxies

NASA Astrophysics Data System (ADS)

Trump, Jonathan R.; Impey, Christopher D.; Kelly, Brandon C.; Civano, Francesca; Gabor, Jared M.; Diamond-Stanic, Aleksandar M.; Merloni, Andrea; Urry, C. Megan; Hao, Heng; Jahnke, Knud; Nagao, Tohru; Taniguchi, Yoshi; Koekemoer, Anton M.; Lanzuisi, Giorgio; Liu, Charles; Mainieri, Vincenzo; Salvato, Mara; Scoville, Nick Z.

2011-05-01

We show how accretion rate governs the physical properties of a sample of unobscured broad-line, narrow-line, and lineless active galactic nuclei (AGNs). We avoid the systematic errors plaguing previous studies of AGN accretion rates by using accurate intrinsic accretion luminosities (L int) from well-sampled multiwavelength spectral energy distributions from the Cosmic Evolution Survey, and accurate black hole masses derived from virial scaling relations (for broad-line AGNs) or host-AGN relations (for narrow-line and lineless AGNs). In general, broad emission lines are present only at the highest accretion rates (L int/L Edd > 10-2), and these rapidly accreting AGNs are observed as broad-line AGNs or possibly as obscured narrow-line AGNs. Narrow-line and lineless AGNs at lower specific accretion rates (L int/L Edd < 10-2) are unobscured and yet lack a broad-line region. The disappearance of the broad emission lines is caused by an expanding radiatively inefficient accretion flow (RIAF) at the inner radius of the accretion disk. The presence of the RIAF also drives L int/L Edd < 10-2 narrow-line and lineless AGNs to have ratios of radio-to-optical/UV emission that are 10 times higher than L int/L Edd > 10-2 broad-line AGNs, since the unbound nature of the RIAF means it is easier to form a radio outflow. The IR torus signature also tends to become weaker or disappear from L int/L Edd < 10-2 AGNs, although there may be additional mid-IR synchrotron emission associated with the RIAF. Together, these results suggest that specific accretion rate is an important physical "axis" of AGN unification, as described by a simple model. Based on observations with the XMM-Newton satellite, an ESA science mission with instruments and contributions directly funded by ESA member states and NASA; the Magellan telescope, operated by the Carnegie Observatories; the ESO Very Large Telescope; and the MMT Observatory, a joint facility of the University of Arizona and the Smithsonian Institution; the Subaru Telescope, operated by the National Astronomical Observatory of Japan; and the NASA/ESA Hubble Space Telescope, operated at the Space Telescope Science Institute, which is operated by AURA Inc., under NASA contract NAS 5-26555.

THE TWO REGIMES OF PHOTOSPHERIC MOTIONS IN {alpha} HYDRA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gray, David F., E-mail: dfgray@uwo.ca

2013-02-10

High-resolution spectroscopic observations of {alpha} Hya were acquired between 2003 and 2010. Analysis of line shifts, differential shifts, line widths, and line bisectors points to two regimes of velocity fields in the photosphere of {alpha} Hya: (1) normal granulation embedded in (2) large convection cells. Variations occur on a wide range of timescales, from several years on down. Radial velocity variations, which are irregular and span 786 m s{sup -1}, have a distribution consistent with a true mean rise velocity of the large cells of {approx}725 m s{sup -1} and a dispersion of {approx}220 m s{sup -1}. The distribution ofmore » granulation velocities, as measured from the widths of spectral lines, shows only small variations, consistent with the two regime concepts. On the multi-year timescale, radial velocity changes, small temperature variations ({approx}10 K), and small line-width variations ({approx}<0.8%) track each other, possibly with phase shifts. The granulation velocity gradient for {alpha} Hya is about half as large as the Sun's and no variation with time was seen, implying that any variation in velocity gradient from one large cell to the next must be less than a few percent. The asymmetry in the granulation velocity distribution, as specified in the flux deficit, is smaller than expected for {alpha} Hya's position in the HR diagram and appears to be variable.« less

Temperature Dependence of Molecular Line Strengths and Fei 1565 nm Zeeman Splitting in a Sunspot

NASA Astrophysics Data System (ADS)

Penn, M. J.; Walton, S.; Chapman, G.; Ceja, J.; Plick, W.

2003-03-01

Spectroscopic observations at 1565 nm were made in the eastern half of the main umbra of NOAA 9885 on 1 April 2002 using the National Solar Observatory McMath-Pierce Telescope at Kitt Peak with a tip-tilt image stabilization system and the California State University Northridge-National Solar Observatory infrared camera. The line depth of the OH blend at 1565.1 nm varies with the observed continuum temperature; the variation fits previous observations except that the continuum temperature is lower by 600 K. The equivalent width of the OH absorption line at 1565.2 nm shows a temperature dependence similar to previously published umbral molecular observations at 640 nm. A simple model of expected OH abundance based upon an ionization analogy to molecular dissociation is produced and agrees well with the temperature variation of the line equivalent width. A CN absorption line at 1564.6 nm shows a very different temperature dependence, likely due to complicated formation and destruction processes. Nonetheless a numerical fit of the temperature variation of the CN equivalent width is presented. Finally a comparison of the Zeeman splitting of the Fei 1564.8 nm line with the sunspot temperature derived from the continuum intensity shows an umbra somewhat cooler for a given magnetic field strength than previous comparisons using this infrared 1564.8 nm line, but consistent with these previous infrared measurements the umbra is hotter for a given magnetic field strength than magnetic and temperature measurements at 630.2 nm would suggest. Differences between the 630.2 nm and 1564.8 nm umbral temperature and magnetic field relations are explained with the different heights of formation of the lines and continua at these wavelengths.

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.

Optical spectroscopy of X-ray sources in the Taurus molecular cloud: discovery of ten new pre-main sequence stars

NASA Astrophysics Data System (ADS)

Scelsi, L.; Sacco, G.; Affer, L.; Argiroffi, C.; Pillitteri, I.; Maggio, A.; Micela, G.

2008-11-01

Aims: We have analyzed optical spectra of 25 X-ray sources identified as potential new members of the Taurus molecular cloud (TMC), in order to confirm their membership in this star-forming region. Methods: Fifty-seven candidate members were previously selected among the X-ray sources in the XEST survey, having a 2MASS counterpart compatible with a pre-main sequence star based on color-magnitude and color-color diagrams. We obtained high-resolution optical spectra for 7 of these candidates with the SARG spectrograph at the TNG telescope, which were used to search for lithium absorption and to measure the Hα line and the radial and rotational velocities. Then, 18 low-resolution optical spectra obtained with the instrument DOLORES for other candidate members were used for spectral classification, for Hα measurements, and to assess membership together with IR color-color and color-magnitude diagrams and additional information from the X-ray data. Results: We found that 3 sources show lithium absorption, with equivalent widths (EWs) of 500 mÅ, broad spectral line profiles, indicating rotational velocities of 20{-}40 km s-1, radial velocities consistent with those for known members, and Hα emission. Two of them are classified as new weak-lined T Tauri stars, while the EW ( -9 Å) of the Hα line and its broad asymmetric profile clearly indicate that the third star (XEST-26-062) is a classical T Tauri star. Fourteen sources observed with DOLORES are M-type stars. Fifteen sources show Hα emission. Six of them have spectra that indicate surface gravity lower than in main sequence stars, and their de-reddened positions in IR color-magnitude diagrams are consistent with their derived spectral type and with pre-main sequence models at the distance of the TMC. The K-type star XEST-11-078 is confirmed as a new member on the basis of the strength of the Hα emission line. Overall, we confirm membership to the TMC for 10 out of 25 X-ray sources observed in the optical. Three sources remain uncertain. Based on data collected with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Centro Galileo Galilei of INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque del los Muchachos of the Instituto de Astrofìsica de Canarias.

High-resolution laser absorption spectroscopy of ozone near 1129.4 cm (-1)

NASA Technical Reports Server (NTRS)

Majorana, L. N.

1981-01-01

A Beer's Law experiment was performed with a tunable diode laser to determine self broadened line shape parameters of one infrared absorption ozone line in the nu1 band for ten pressures from 0.26 to 6.29 torr at 285 K. The SO2 line positions were used for wavelength calibration. Line shapes were iteratively fitted to the Voigt function at a Doppler width of 29.54 MHz (HWHM) resulting in values for the integrated line strength, (S), of (0.144 +/- 0.007) x 10 to the minus 20th/cm molecule/cu cm, line center frequency, nu sub o, of 1129.426/cm and the Lorentzian contributions to halfwidth. A linear least squares fit of (alpha sub L)5 as a function of pressure yielded a zero intercept of 15.27 +/- 0.29 MHz (rho = 0.99) and a broadening parameter, (alpha sub L)5, of 5.71 +/- 0.29 MHz/Torr. This results in a line width (FWHM) of 0.144 +/- .007/cm at 760 torr and 285 K.

Note: A rectangular pulse generator for 50 kV voltage, 0.8 ns rise time, and 10 ns pulse width based on polymer-film switch.

PubMed

Wu, Hanyu; Zhang, Xinjun; Sun, Tieping; Zeng, Zhengzhong; Cong, Peitian; Zhang, Shaoguo

2015-10-01

In this article, we describe a rectangular pulse generator, consisting of a polymer-film switch, a tri-plate transmission line, and parallel post-shaped ceramic resistor load, for 50-kV voltage, 0.8-ns rise time, and 10-ns width. The switch and resistors are arranged in atmospheric air and the transmission line can work in atmospheric air or in transformer oil to change the pulse width from 6.7 ns to 10 ns. The fast switching and low-inductance characteristics of the polymer-film switch ensure the fast rising wavefront of <1 ns. This generator can be applied in the calibration of nanosecond voltage dividers and used for electromagnetic pulse tests as a fast-rising current injection source.

The different origins of high- and low-ionization broad emission lines revealed by gravitational microlensing in the Einstein cross

NASA Astrophysics Data System (ADS)

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

2016-07-01

We investigate the kinematics and ionization structure of the broad emission line region of the gravitationally lensed quasar QSO2237+0305 (the Einstein cross) using differential microlensing in the high- and low-ionization broad emission lines. We combine visible and near-infrared spectra of the four images of the lensed quasar and detect a large-amplitude microlensing effect distorting the high-ionization CIV and low-ionization Hα line profiles in image A. While microlensing only magnifies the red wing of the Balmer line, it symmetrically magnifies the wings of the CIV emission line. Given that the same microlensing pattern magnifies both the high- and low-ionization broad emission line regions, these dissimilar distortions of the line profiles suggest that the high- and low-ionization regions are governed by different kinematics. Since this quasar is likely viewed at intermediate inclination, we argue that the differential magnification of the blue and red wings of Hα favors a flattened, virialized, low-ionization region whereas the symmetric microlensing effect measured in CIV can be reproduced by an emission line formed in a polar wind, without the need of fine-tuned caustic configurations. Based on observations made with the ESO-VLT, Paranal, Chile; Proposals 076.B-0197 and 076.B-0607 (PI: Courbin).

Development and applications of tunable, narrow band lasers and stimulated Raman scattering devices for atmospheric lidar

NASA Technical Reports Server (NTRS)

Wilkerson, Thomas D.

1993-01-01

The main thrust of the program was the study of stimulated Raman processes for application to atmospheric lidar measurements. This has involved the development of tunable lasers, the detailed study of stimulated Raman scattering, and the use of the Raman-shifted light for new measurements of molecular line strengths and line widths. The principal spectral region explored in this work was the visible and near-IR wavelengths between 500 nm and 1.5 microns. Recent alexandrite ring laser experiments are reported. The experiments involved diode injection-locking, Raman shifting, and frequency-doubling. The experiments succeeded in producing tunable light at 577 and 937 nm with line widths in the range 80-160 MHz.

The Sloan Digital Sky Survey Reverberation Mapping Project: Composite Lags at z ≤ 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Jennifer; Shen, Yue; Horne, Keith

We present composite broad-line region (BLR) reverberation mapping lag measurements for H α , H β , He ii λ 4686, and Mg ii for a sample of 144, z ≲ 1 quasars from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project. Using only the 32-epoch spectroscopic light curves in the first six-month season of SDSS-RM observations, we compile correlation function measurements for individual objects and then coadd them to allow the measurement of the average lags for our sample at mean redshifts of 0.4 (for H α ) and ∼0.65 (for the other lines). At similar quasar luminositiesmore » and redshifts, the sample-averaged lag decreases in the order of Mg ii, H α , H β , and He ii. This decrease in lags is accompanied by an increase in the mean line width of the four lines, and is roughly consistent with the virialized motion for BLR gas in photoionization equilibrium. These are among the first RM measurements of stratified BLR structure at z > 0.3. Dividing our sample by luminosity, H α shows clear evidence of increasing lags with luminosity, consistent with the expectation from the measured BLR size–luminosity relation based on H β . The other three lines do not show a clear luminosity trend in their average lags due to the limited dynamic range of luminosity probed and the poor average correlation signals in the divided samples, a situation that will be improved with the incorporation of additional photometric and spectroscopic data from SDSS-RM. We discuss the utility and caveats of composite lag measurements for large statistical quasar samples with reverberation mapping data.« less

The Sloan Digital Sky Survey Reverberation Mapping Project: Composite Lags at z ≤ 1

NASA Astrophysics Data System (ADS)

Li, Jennifer; Shen, Yue; Horne, Keith; Brandt, W. N.; Greene, Jenny E.; Grier, C. J.; Ho, Luis C.; Kochanek, Chris; Schneider, Donald P.; Trump, Jonathan R.; Dawson, Kyle S.; Pan, Kaike; Bizyaev, Dmitry; Oravetz, Daniel; Simmons, Audrey; Malanushenko, Elena

2017-09-01

We present composite broad-line region (BLR) reverberation mapping lag measurements for Hα, Hβ, He II λ4686, and Mg II for a sample of 144, z ≲ 1 quasars from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project. Using only the 32-epoch spectroscopic light curves in the first six-month season of SDSS-RM observations, we compile correlation function measurements for individual objects and then coadd them to allow the measurement of the average lags for our sample at mean redshifts of 0.4 (for Hα) and ˜0.65 (for the other lines). At similar quasar luminosities and redshifts, the sample-averaged lag decreases in the order of Mg II, Hα, Hβ, and He II. This decrease in lags is accompanied by an increase in the mean line width of the four lines, and is roughly consistent with the virialized motion for BLR gas in photoionization equilibrium. These are among the first RM measurements of stratified BLR structure at z > 0.3. Dividing our sample by luminosity, Hα shows clear evidence of increasing lags with luminosity, consistent with the expectation from the measured BLR size-luminosity relation based on Hβ. The other three lines do not show a clear luminosity trend in their average lags due to the limited dynamic range of luminosity probed and the poor average correlation signals in the divided samples, a situation that will be improved with the incorporation of additional photometric and spectroscopic data from SDSS-RM. We discuss the utility and caveats of composite lag measurements for large statistical quasar samples with reverberation mapping data.

Reverberation Mapping of the Kepler-Field AGN KA1858+4850

NASA Technical Reports Server (NTRS)

Pei, Liuyi; Barth, Aaron J.; Aldering, Greg S.; Briley, Michael M.; Carroll, Carla J.; Carson, Daniel J.; Cenko, S., Bradley; Clubb, Kelsey I.; Cohen, Daniel P.; Cucchiara, Antonino;

The variability of the Seyfert galaxy NGC 2992: the case for a revived AGN

NASA Astrophysics Data System (ADS)

Gilli, R.; Maiolino, R.; Marconi, A.; Risaliti, G.; Dadina, M.; Weaver, K. A.; Colbert, E. J. M.

2000-03-01

We report the transition to an active state of the nucleus in the Seyfert 1.9 galaxy NGC 2992, discovered by means of new hard X-ray data. While the 2-10 keV flux declined by a factor of ~ 20 from 1978 to 1994, two recent BeppoSAX observations in 1997 and in 1998 caught the nuclear emission raising back to the same level of activity observed in 1978. In both BeppoSAX observations the X-ray spectrum of the source is well represented by a power law with spectral index Gamma =~ 1.7, absorbed by a column density of N_H =~ 1022 cm-2 and characterized by a prominent iron Kalpha line. While in the second BeppoSAX data set the line properties appear to be consistent with those expected from accretion disc models, in the first BeppoSAX data set the iron feature is rather peculiar. The broadening is not significant and the line energy is E_Kalpha =6.62+/-0.07 keV, indicating emission from highly ionized iron. The line has too high equivalent width ( ~ 700 eV) to be produced by a hot scattering medium. By comparing these data with data previously in the literature, we interpret the spectral and flux changes in terms of different phases of rebuilding an accretion disc. The timescale for the disc rebuilding is estimated to range between 1 and 5 years. The X-ray data are complemented with optical and near-infrared followup spectra taken 1.5 months after the discovery of the X-ray burst. The spectra are characterized by prominent broad emission lines. There is also evidence for hot dust emission in the H and K bands that, however, is probably still in the process of increasing.

SALT long-slit spectroscopy of LBQS 2113-4538: variability of the Mg II and Fe II component

NASA Astrophysics Data System (ADS)

Hryniewicz, K.; Czerny, B.; Pych, W.; Udalski, A.; Krupa, M.; Świȩtoń, A.; Kaluzny, J.

2014-02-01

Context. The Mg II line is of extreme importance in intermediate redshift quasars since it allows us to measure the black hole mass in these sources and to use these sources as probes of the distribution of dark energy in the Universe, as a complementary tool to SN Ia. Aims: Reliable use of Mg II requires a good understanding of all the systematic effects involved in the measurement of the line properties, including the contamination by Fe II UV emission. Methods: We performed three spectroscopic observations of a quasar LBQS 2113-4538 (z = 0.956) with the SALT telescope, separated in time by several months and we analyze in detail the mean spectrum and the variability in the spectral shape. Results: We show that even in our good-quality spectra the Mg II doublet is well fit by a single Lorentzian shape. We tested several models of the Fe II pseudo-continuum and showed that one of them well represents all the data. The amplitudes of both components vary in time, but the shapes do not change significantly. The measured line width of LBQS 2113-4538 identifies this object as a class A quasar. The upper limit of 3% for the contribution of the narrow line region (NLR) to Mg II may suggest that the separation of the broad line region and NLR disappears in this class of objects. Based on observations made with the Southern African Large Telescope (SALT) under program 2012-1-POL-008 (PI: Czerny).Fe II template shown in Fig. 8 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/562/A34

Reverberation Mapping of the KEPLER Field AGN KA1858+4850

NASA Astrophysics Data System (ADS)

Pei, Liuyi; Barth, Aaron J.; Aldering, Greg S.; Briley, Michael M.; Carroll, Carla J.; Carson, Daniel J.; Cenko, S. Bradley; Clubb, Kelsey I.; Cohen, Daniel P.; Cucchiara, Antonino; Desjardins, Tyler D.; Edelson, Rick; Fang, Jerome J.; Fedrow, Joseph M.; Filippenko, Alexei V.; Fox, Ori D.; Furniss, Amy; Gates, Elinor L.; Gregg, Michael; Gustafson, Scott; Horst, J. Chuck; Joner, Michael D.; Kelly, Patrick L.; Lacy, Mark; Laney, C. David; Leonard, Douglas C.; Li, Weidong; Malkan, Matthew A.; Margon, Bruce; Neeleman, Marcel; Nguyen, My L.; Prochaska, J. Xavier; Ross, Nathaniel R.; Sand, David J.; Searcy, Kinchen J.; Shivvers, Isaac S.; Silverman, Jeffrey M.; Smith, Graeme H.; Suzuki, Nao; Smith, Krista Lynne; Tytler, David; Werk, Jessica K.; Worseck, Gábor

2014-11-01

KA1858+4850 is a narrow-line Seyfert 1 galaxy at redshift 0.078 and is among the brightest active galaxies monitored by the Kepler mission. We have carried out a reverberation mapping campaign designed to measure the broad-line region size and estimate the mass of the black hole in this galaxy. We obtained 74 epochs of spectroscopic data using the Kast Spectrograph at the Lick 3 m telescope from 2012 February to November, and obtained complementary V-band images from five other ground-based telescopes. We measured the Hβ light curve lag with respect to the V-band continuum light curve using both cross-correlation techniques (CCF) and continuum light curve variability modeling with the JAVELIN method and found rest-frame lags of τ CCF = 13.53+2.03-2.32 days and τ JAVELIN = 13.15+1.08-1.00 days. The Hβ rms line profile has a width of σline = 770 ± 49 km s-1. Combining these two results and assuming a virial scale factor of f = 5.13, we obtained a virial estimate of M{BH} = 8.06+1.59-1.72 × 106 {M}⊙ for the mass of the central black hole and an Eddington ratio of L/L Edd ≈ 0.2. We also obtained consistent but slightly shorter emission-line lags with respect to the Kepler light curve. Thanks to the Kepler mission, the light curve of KA1858+4850 has among the highest cadences and signal-to-noise ratios ever measured for an active galactic nucleus; thus, our black hole mass measurement will serve as a reference point for relations between black hole mass and continuum variability characteristics in active galactic nuclei.

Three-dimensional finite-element analysis of chevron-notched fracture specimens

NASA Technical Reports Server (NTRS)

Raju, I. S.; Newman, J. C., Jr.

1984-01-01

Stress-intensity factors and load-line displacements were calculated for chevron-notched bar and rod fracture specimens using a three-dimensional finite-element analysis. Both specimens were subjected to simulated wedge loading (either uniform applied displacement or uniform applied load). The chevron-notch sides and crack front were assumed to be straight. Crack-length-to-specimen width ratios (a/w) ranged from 0.4 to 0.7. The width-to-thickness ratio (w/B) was 1.45 or 2. The bar specimens had a height-to-width ratio of 0.435 or 0.5. Finite-element models were composed of singularity elements around the crack front and 8-noded isoparametric elements elsewhere. The models had about 11,000 degrees of freedom. Stress-intensity factors were calculated by using a nodal-force method for distribution along the crack front and by using a compliance method for average values. The stress intensity factors and load-line displacements are presented and compared with experimental solutions from the literature. The stress intensity factors and load-line displacements were about 2.5 and 5 percent lower than the reported experimental values, respectively.

Analysis of He I 1083 nm Imaging Spectroscopy Using a Spectral Standard

NASA Technical Reports Server (NTRS)

Malanushenko, Elena V.; Jones, Harrison P.

2004-01-01

We develop a technique. for the analysis of He I 1083 nanometer spectra which addresses several difficulties through determination of a continuum background by comparison with a well calibrated standard and through removal of nearby solar and telluric blends by differential comparison to an average spectrum. The method is compared with earlier analysis of imaging spectroscopy obtained at the National Solar Observatory/Kitt Peak Vacuum Telescope (NSO/KPVT) with the NASA/NSO Spectromagnetograph (SPM). We examine distributions of Doppler velocity and line width as a function of central intensity for an active region, filament, quiet Sun, and coronal hole. For our example, we find that line widths and central intensity are oppositely correlated in a coronal hole and quiet Sun. Line widths are comparable to the quiet sun in the active region, are systematically lower in the filament, and extend to higher values in the coronal hole. Outward velocities of approximately equal to 2 to 4 kilometers per second are typically observed in the coronal hole. The sensitivity of these results to analysis technique is discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kobayashi, Hirokazu

One-dimensional (1D) molecular chains of 4-substituted-2,2,6,6-tetramethyl-1-piperidinyloxyl (4-X-TEMPO) radicals were constructed in the crystalline 1D nanochannels of 2,4,6-tris(4-chlorophenoxy)-1,3,5-triazine (CLPOT) used as a template. The ESR spectra of CLPOT inclusion compounds (ICs) using 4-X-TEMPO were examined on the basis of spectral simulation using EasySpin program package for simulating and fitting ESR spectra. The ESR spectra of [(CLPOT){sub 2}-(TEMPO){sub 1.0}] IC were isotropic in the total range of temperatures. The peak-to-peak line width (ΔB{sub pp}) became monotonically narrower from 2.8 to 1.3 mT with increase in temperature in the range of 4.2–298 K. The effect of the rotational diffusion motion of TEMPO radicals inmore » the CLPOT nanochannels for the inter-spin interaction of the [(CLPOT){sub 2}-(TEMPO){sub 1.0}] IC was found to be smaller than the case of [(TPP){sub 2}−(TEMPO){sub 1.0}] IC (TPP = tris(o-phenylenedioxy)cyclotriphosphazene) reported in our previous study. The ΔB{sub pp} of the [(CLPOT){sub 2}-(TEMPO){sub 1.0}] IC in the whole range of temperatures was much narrower than the estimation to be based on the Van Vleck’s formula for the second moment of the rigid lattice model where the electron spin can be considered as fixed; 11 mT of Gaussian line-width component. This suggests the possibility of exchange narrowing in the 1D organic-radical chains of the [(CLPOT){sub 2}-(TEMPO){sub 1.0}] IC. On the other hand, the ESR spectra of [(CLPOT){sub 2}-(MeO-TEMPO){sub 0.41}] IC (MeO-TEMPO = 4-methoxy-TEMPO) were reproduced by a superposition of major broad isotropic adsorption line and minor temperature-dependent modulated triplet component. This suggests that the IC has the part of 1D organic-radical chains and MeO-TEMPO molecules isolated in the CLPOT nanochannels.« less

Ultra-Wideband Optical Modulation Spectrometer (OMS) Development

NASA Technical Reports Server (NTRS)

Gardner, Jonathan (Technical Monitor); Tolls, Volker

2004-01-01

The optical modulation spectrometer (OMS) is a novel, highly efficient, low mass backend for heterodyne receiver systems. Current and future heterodyne receiver systems operating at frequencies up to a few THz require broadband spectrometer backends to achieve spectral resolutions of R approximately 10(exp 5) to 10(exp 6) to carry out many important astronomical investigations. Among these are observations of broad emission and absorption lines from extra-galactic objects at high redshifts, spectral line surveys, and observations of planetary atmospheres. Many of these lines are pressure or velocity broadened with either large half-widths or line wings extending over several GHz. Current backend systems can cover the needed bandwidth only by combining the output of several spectrometers, each with typically up to 1 GHz bandwidth, or by combining several frequency-shifted spectra taken with a single spectrometer. An ultra-wideband optical modulation spectrometer with 10 - 40 GHz bandwidth will enable broadband ob- servations without the limitations and disadvantages of hybrid spectrometers. Spectrometers like the OMS will be important for both ground-based observatories and future space missions like the Single Aperture Far-Infrared Telescope (SAFIR) which might carry IR/submm array heterodyne receiver systems requiring a spectrometer for each array pixel. Small size, low mass and small power consumption are extremely important for space missions. This report summarizes the specifications developed for the OMS and lists already identified commercial parts. The report starts with a review of the principle of operation, then describes the most important components and their specifications which were derived from theory, and finishes with a conclusion and outlook.

2.5 MHz Line-Width High-energy, 2 Micrometer Coherent Wind Lidar Transmitter

NASA Technical Reports Server (NTRS)

Petros, Mulugeta; Yu, Jirong; Trieu, Bo; Bai, Yingxin; Petzar, Paul; Singh, Upendra N.; Reithmaier, Karl

2007-01-01

2 micron solid-state lasers are the primary choice for coherent Doppler wind detection. As wind lidars, they are used for wake vortex and clear air turbulence detection providing air transport safety. In addition, 2 micron lasers are one of the candidates for CO2 detection lidars. The rich CO2 absorption line around 2 micron, combined with the long upper state life of time, has made Ho based 2 micron lasers a viable candidate for CO2 sensing DIAL instrument. The design and fabrication of a compact coherent laser radar transmitter for Troposphere wind sensing is under way. This system is hardened for ground as well as airborne applications. As a transmitter for a coherent wind lidar, this laser has stringent spectral line width and beam quality requirements. Although the absolute wavelength does not have to be fixed for wind detection, to maximize return signal, the output wavelength should avoid atmospheric CO2 and H2O absorption lines. The base line laser material is Ho:Tm:LuLF which is an isomorph of Ho:Tm:YLF. LuLF produces 20% more output power than Ho:Tm:YLF. In these materials the Tm absorption cross-section, the Ho emission cross-section, the Tm to Ho energy transfer parameters and the Ho (sup 5) I (sub 7) radiative life time are all identical. However, the improved performance of the LuLF is attributed to the lower thermal population in the (sup 5) I (sub 8) manifold. It also provides higher normal mode to Q-switch conversion than YLF at high pump energy indicating a lower up-conversion. The laser architecture is composed of a seed laser, a ring oscillator, and a double pass amplifier. The seed laser is a single longitudinal mode with a line width of 13 KHz. The 100mJ class oscillator is stretched to 3 meters to accommodate the line-width requirement without compromising the range resolution of the instrument. The amplifier is double passed to produce greater than 300mJ energy.

Broad absorption-line time variability in the QSO CSO 203

NASA Technical Reports Server (NTRS)

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

1992-01-01

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

DETECTION OF BROAD Hα EMISSION LINES IN THE LATE-TIME SPECTRA OF A HYDROGEN-POOR SUPERLUMINOUS SUPERNOVA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Lin; Masci, F.; Quimby, R.

2015-12-01

iPTF13ehe is a hydrogen-poor superluminous supernova (SLSN) at z = 0.3434, with a slow-evolving light curve and spectral features similar to SN2007bi. It rises in 83–148 days to reach a peak bolometric luminosity of ∼1.3 × 10{sup 44} erg s{sup −1}, then decays slowly at 0.015 mag day{sup −1}. The measured ejecta velocity is ∼ 13,000 km s{sup −1}. The inferred explosion characteristics, such as the ejecta mass (70–220 M{sub ⊙}), and the total radiative and kinetic energy (E{sub rad} ∼ 10{sup 51} erg, E{sub kin} ∼ 2 × 10{sup 53} erg), are typical of slow-evolving H-poor SLSN events. However,more » the late-time spectrum taken at +251 days (rest, post-peak) reveals a Balmer Hα emission feature with broad and narrow components, which has never been detected before among other H-poor SLSNe. The broad component has a velocity width of ∼4500 km s{sup −1} and a ∼300 km s{sup −1} blueward shift relative to the narrow component. We interpret this broad Hα emission with a luminosity of ∼2 × 10{sup 41} erg s{sup −1} as resulting from the interaction between the supernova ejecta and a discrete H-rich shell, located at a distance of ∼4 × 10{sup 16} cm from the explosion site. This interaction causes the rest-frame r-band LC to brighten at late times. The fact that the late-time spectra are not completely absorbed by the shock-ionized H-shell implies that its Thomson scattering optical depth is likely ≤1, thus setting upper limits on the shell mass ≤30 M{sub ⊙}. Of the existing models, a Pulsational Pair Instability supernova model can naturally explain the observed 30 M{sub ⊙} H-shell, ejected from a progenitor star with an initial mass of (95–150) M{sub ⊙} about 40 years ago. We estimate that at least ∼15% of all SLSNe-I may have late-time Balmer emission lines.« less

The Effects of High Frequency ULF Wave Activity on the Spectral Characteristics of Coherent HF Radar Returns

NASA Astrophysics Data System (ADS)

Wright, D. M.; Yeoman, T. K.; Woodfield, E. E.

2003-12-01

It is now a common practice to employ ground-based radars in order to distinguish between those regions of the Earth's upper atmosphere which are magnetically conjugate to open and closed field lines. Radar returns from ionospheric irregularities inside the polar cap and cusp regions generally exhibit large spectral widths in contrast to those which exist on closed field lines at lower latitudes. It has been suggested that the so-called Spectral Width Boundary (SWB) might act as a proxy for the open-closed field line boundary (OCFLB), which would then be an invaluable tool for investigating reconnection rates in the magnetosphere. The exact cause of the increased spectral widths observed at very high latitudes is still subject to considerable debate. Several mechanisms have been proposed. This paper compares a dusk-sector interval of coherent HF radar data with measurements made by an induction coil magnetometer located at Tromso, Norway (66° N geomagnetic). On this occasion, a series of transient regions of radar backscatter exhibiting large spectral widths are accompanied by increases in spectral power of ULF waves in the Pc1-2 frequency band. These observations would then, seem to support the possibility that high frequency magnetospheric wave activity at least contribute to the observed spectral characteristics and that such wave activity might play a significant role in the cusp and polar cap ionospheres.

Spectrum radial velocity analyser (SERVAL). High-precision radial velocities and two alternative spectral indicators

NASA Astrophysics Data System (ADS)

Zechmeister, M.; Reiners, A.; Amado, P. J.; Azzaro, M.; Bauer, F. F.; Béjar, V. J. S.; Caballero, J. A.; Guenther, E. W.; Hagen, H.-J.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Launhardt, R.; Montes, D.; Morales, J. C.; Quirrenbach, A.; Reffert, S.; Ribas, I.; Seifert, W.; Tal-Or, L.; Wolthoff, V.

2018-01-01

Context. The CARMENES survey is a high-precision radial velocity (RV) programme that aims to detect Earth-like planets orbiting low-mass stars. Aims: We develop least-squares fitting algorithms to derive the RVs and additional spectral diagnostics implemented in the SpEctrum Radial Velocity AnaLyser (SERVAL), a publicly available python code. Methods: We measured the RVs using high signal-to-noise templates created by coadding all available spectra of each star. We define the chromatic index as the RV gradient as a function of wavelength with the RVs measured in the echelle orders. Additionally, we computed the differential line width by correlating the fit residuals with the second derivative of the template to track variations in the stellar line width. Results: Using HARPS data, our SERVAL code achieves a RV precision at the level of 1 m/s. Applying the chromatic index to CARMENES data of the active star YZ CMi, we identify apparent RV variations induced by stellar activity. The differential line width is found to be an alternative indicator to the commonly used full width half maximum. Conclusions: We find that at the red optical wavelengths (700-900 nm) obtained by the visual channel of CARMENES, the chromatic index is an excellent tool to investigate stellar active regions and to identify and perhaps even correct for activity-induced RV variations.

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Science.gov Websites

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Science.gov Websites

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The D1Πu state of HD and the mass scaling relation of its predissociation widths

NASA Astrophysics Data System (ADS)

Dickenson, G. D.; Ubachs, W.

2012-07-01

Absorption spectra of HD have been recorded in the wavelength range of 75-90 nm at 100 K using the vacuum ultraviolet Fourier transform spectrometer at the Synchrotron SOLEIL. The present wavelength resolution represents an order of magnitude improvement over that of previous studies. We present a detailed study of the D1Πu-X1Σ+g system observed up to v‧ = 18. The Q-branch transition probing levels of Π- symmetry are observed as narrow resonances limited by the Doppler width at 100 K. Line positions for these transitions are determined to an estimated absolute accuracy of 0.06 cm-1. Predissociation line widths of Π+ levels are extracted from the absorption spectra. A comparison with the recent results on a study of the D1Πu state in H2 and D2 reveals that the predissociation widths scale as μ-2J(J + 1), with μ being the reduced mass of the molecule and J the rotational angular momentum quantum number, as expected from an interaction with the B‧1Σ+u continuum causing the predissociation.

Coupling Between Microstrip Lines With Finite Width Ground Plane Embedded in Thin Film Circuits

NASA Technical Reports Server (NTRS)

Ponchak, George E.; Dalton, Edan; Tentzeris, Manos M.; Papapolymerou, John

2003-01-01

Three-dimensional (3D) interconnects built upon multiple layers of polyimide are required for constructing 3D circuits on CMOS (low resistivity) Si wafers, GaAs, and ceramic substrates. Thin film microstrip lines (TFMS) with finite width ground planes embedded in the polyimide are often used. However, the closely spaced TFMS lines a r e susceptible to high levels of coupling, which degrades circuit performance. In this paper, Finite Difference Time Domain (FDTD) analysis and experimental measurements a r e used to show that the ground planes must be connected by via holes to reduce coupling in both the forward and backward directions. Furthermore, it is shown that coupled microstrip lines establish a slotline type mode between the two ground planes and a dielectric waveguide type mode, and that the via holes recommended here eliminate these two modes.

Measurement of the profile and intensity of the solar He I lambda 584-A resonance line

NASA Technical Reports Server (NTRS)

Maloy, J. O.; Hartmann, U. G.; Judge, D. L.; Carlson, R. W.

1978-01-01

The intensity and profile of the helium resonance line at 584 A from the entire disk of the sun was investigated by using a rocket-borne helium-filled spectrometer and a curve-of-growth technique. The line profile was found to be accurately represented by a Gaussian profile with full width at half maximum of 122 + or - 10 mA, while the integrated intensity was measured to be 2.6 + or - 1.3 billion photons/s per sq cm at solar activity levels of F(10.7) = 90.8 x 10 to the -22nd per sq m/Hz and Rz = 27. The measured line width is in good agreement with previous spectrographic measurements, but the integrated intensity is larger than most previous photoelectric measurements. However, the derived line center flux of 20 + or - 10 billion photons/s per sq cm/A is in good agreement with values inferred from airglow measurements.

Dynamic "Scanning-Mode" Meniscus Confined Electrodepositing and Micropatterning of Individually Addressable Ultraconductive Copper Line Arrays.

PubMed

Lei, Yu; Zhang, Xianyun; Xu, Dingding; Yu, Minfeng; Yi, Zhiran; Li, Zhixiang; Sun, Aihua; Xu, Gaojie; Cui, Ping; Guo, Jianjun

2018-05-03

Micro- and nanopatterning of cost-effective addressable metallic nanostructures has been a long endeavor in terms of both scientific understanding and industrial needs. Herein, a simple and efficient dynamic meniscus-confined electrodeposition (MCED) technique for precisely positioned copper line micropatterns with superior electrical conductivity (greater than 1.57 × 10 4 S/cm) on glass, silicon, and gold substrates is reported. An unexpected higher printing speed in the evaporative regime is realized for precisely positioned copper lines patterns with uniform width and height under horizontal scanning-mode. The final line height and width depend on the typical behavior of traditional flow coating process, while the surface morphologies and roughness are mainly governed by evaporation-driven electrocrystallization dynamics near the receding moving contact line. Integrated 3D structures and a rapid prototyping of 3D hot-wire anemometer are further demonstrated, which is very important for the freedom integration applications in advanced conceptual devices, such as miniaturized electronics and biomedical sensors and actuators.

[The application of Doppler broadening and Doppler shift to spectral analysis].

PubMed

Xu, Wei; Fang, Zi-shen

2002-08-01

The distinction between Doppler broadening and Doppler shift has analyzed, Doppler broadening locally results from the distribution of velocities of the emitting particles, the line width gives the information on temperature of emitting particles. Doppler shift results when the emitting particles have a bulk non random flow velocity in a particular direction, the drift of central wavelength gives the information on flow velocity of emitting particles, and the Doppler shift only drifts the profile of line without changing the width. The difference between Gaussian fitting and the distribution of chord-integral line shape have also been discussed. The distribution of H alpha spectral line shape has been derived from the surface of limiter in HT-6M Tokamak with optical spectroscope multichannel analysis (OSMA), the result by double Gaussian fitting shows that the line shape make up of two port, the emitting of reflect particles with higher energy and the release particle from the limiter surface. Ion temperature and recycling particle flow velocity have been obtained from Doppler broadening and Doppler shift.

Formation of conductive copper lines by femtosecond laser irradiation of copper nitride film on plastic substrates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Xiaodong; Yuan, Ningyi, E-mail: nyyuan@cczu.edu.cn; Center for Low-Dimensional Materials, Micro-Nano Devices and Systems, Changzhou University, Changzhou 213164, Jiangsu

2015-05-15

In this paper, we report a simple method to form conductive copper lines by scanning a single-beam femtosecond pulse laser on a plastic substrate covered with copper nitride (Cu{sub 3}N) film. The Cu{sub 3}N films were prepared by DC magnetron sputtering in the presence of an Ar + N{sub 2} atmosphere at 100 °C. The influence of the laser power and scanning speed on the formed copper line width, surface features, and morphology was analyzed by means of optical microscopy, X-ray diffraction, non-contact 3D profilometer, and scanning electron microscopy. The experimental results demonstrate that low laser power and low scanningmore » speed favor the formation of uniform and flat Cu lines. After process optimization, copper lines with a width less than 5 μm were obtained, which provides an attractive application prospect in the field of flexible electronic devices.« less

Stocking, growth, and habitat relations in New Hampshire hardwoods

Treesearch

William B. Leak

1983-01-01

Data from hardwood stands in New Hampshire substantiated the crown-width relationships used to develop the B-line (based on circular crowns) in the 1969 northern hardwood stocking guide, and produced an A-line slightly lower than the original line. Position of the A-line was unrelated to site or forest type. Diameter growth of hardwoods on moist and dry soils declined...

An Empirical Expression for the Line Widths of Ammonia

NASA Technical Reports Server (NTRS)

Brown, Linda R.; Peterson, Dean B.

1994-01-01

The hydrogen-broadened line widths of 116 (sup 14)NH(sub 3) ground state transitions have been measured at 0.006 cm(sup -1) resolution using a Bruker spectrometer in the 24 to 210 cm(sup -1) region. The rotational variation of the experimental widths with J(sup '),K(sup ') = 1,0 to 10,10 has been reproduced to 2.4 % using an heuristically derived expression of the form

gamma = a(sub 0) + a(sub 1) J(sup ') + a (sub 2) K(sup ') + a(sub 3) J(sup ')(sup 2) + a(sub 4) J(sup ') K(sup ')

where J(sup ') and K(sup ') are the lower state symmetric top quantum numbers. This function has also been applied to the measured widths of the 58 transitions of nu(sub 1) at 3 (micro)m, each broadened by N(sub 2), O(sub 2), Ar, H(sub 2), and He. The rms of the observed minus calculated widths are 5% or better for the five foreign broadeners. The values of the fitted constants suggest that for some broadeners the expression might also be written as

gamma = a(sub 0) + b(sub 1) J(sup ') + b(sub 2)(J(sup ' )- K(sup ')) + b(sub 3) J(sup ')(J(sup ') - K(sup '))

.

Particle-in-Cell Simulation of Collisionless Driven Reconnection with Open Boundaries

NASA Technical Reports Server (NTRS)

Kimas, Alex; Hesse, Michael; Zenitani, Seiji; Kuznetsova, Maria

2010-01-01

First results are discussed from an ongoing study of driven collisionless reconnection using a 2 1/2-dimensional electromagnetic particle-in-cell simulation model with open inflow and outflow boundaries. An extended electron diffusion region (EEDR) is defined as that region surrounding a reconnecting neutral line in which the out-of-plane nonideal electric field is positive. It is shown that the boundaries of this region in the directions of the outflow jets are at the positions where the electrons make the transition from unfrozen meandering motion in the current sheet to outward drifting with the magnetic field in the outflow jets; a turning length scale is defined to mark these positions, The initial width of the EEDR in the inflow directions is comparable to the electron bounce width. Later. as shoulders develop to form a two-scale structure. thc EEDR width expands to the ion bounce width scale. The inner portion of the EEDR or the electron diffusion region proper remains at the electron bounce width. Two methods are introduced for predicting the reconnection electric field using the dimensions of the EEDR. These results are interpreted as further evidence that the EEDR is the region that is relevant to understanding the electron role in the neutral line vicinity.

Semantic, perceptual and number space: relations between category width and spatial processing.

PubMed

Brugger, Peter; Loetscher, Tobias; Graves, Roger E; Knoch, Daria

2007-05-17

Coarse semantic encoding and broad categorization behavior are the hallmarks of the right cerebral hemisphere's contribution to language processing. We correlated 40 healthy subjects' breadth of categorization as assessed with Pettigrew's category width scale with lateral asymmetries in perceptual and representational space. Specifically, we hypothesized broader category width to be associated with larger leftward spatial biases. For the 20 men, but not the 20 women, this hypothesis was confirmed both in a lateralized tachistoscopic task with chimeric faces and a random digit generation task; the higher a male participant's score on category width, the more pronounced were his left-visual field bias in the judgement of chimeric faces and his small-number preference in digit generation ("small" is to the left of "large" in number space). Subjects' category width was unrelated to lateral displacements in a blindfolded tactile-motor rod centering task. These findings indicate that visual-spatial functions of the right hemisphere should not be considered independent of the same hemisphere's contribution to language. Linguistic and spatial cognition may be more tightly interwoven than is currently assumed.

Shock-heated NH3 in a Molecular Jet Associated with a High-Mass Young Star.

PubMed

Zhang; Hunter; Sridharan; Cesaroni

1999-12-20

We present the discovery of shock-excited NH3 in a well-collimated jet associated with the extremely young high-mass star IRAS 20126+4104. The NH3 (3, 3) and (4, 4) emission is dominated by three clumps along the SiO jet. At the end of the jet, there exists strong and broad (+/-10 km s-1) NH3 (3, 3) emission. With typical brightness temperatures greater than 500 K, the overall emission indicates a weakly inverted population and appears in an arc, consistent with the excitation by bow shocks. There are two bright spots in the NH3 (3, 3) emission with brightness temperatures of approximately 2000 K. The narrow line width (1.5 km s-1 FWHM), the small sizes (<0&farcs;3), and the unusually high brightness temperature of the features are indicative of maser emission. Our observations provide clear evidence that NH3 (3, 3) masers are excited in shock regions in molecular outflows.

Isotope labeling for studying RNA by solid-state NMR spectroscopy.

PubMed

Marchanka, Alexander; Kreutz, Christoph; Carlomagno, Teresa

2018-04-12

Nucleic acids play key roles in most biological processes, either in isolation or in complex with proteins. Often they are difficult targets for structural studies, due to their dynamic behavior and high molecular weight. Solid-state nuclear magnetic resonance spectroscopy (ssNMR) provides a unique opportunity to study large biomolecules in a non-crystalline state at atomic resolution. Application of ssNMR to RNA, however, is still at an early stage of development and presents considerable challenges due to broad resonances and poor dispersion. Isotope labeling, either as nucleotide-specific, atom-specific or segmental labeling, can resolve resonance overlaps and reduce the line width, thus allowing ssNMR studies of RNA domains as part of large biomolecules or complexes. In this review we discuss the methods for RNA production and purification as well as numerous approaches for isotope labeling of RNA. Furthermore, we give a few examples that emphasize the instrumental role of isotope labeling and ssNMR for studying RNA as part of large ribonucleoprotein complexes.

X-ray optics for WHIMex: the Warm Hot Intergalactic Medium Explorer

NASA Astrophysics Data System (ADS)

Cash, W.; McEntaffer, R.; Zhang, W.; Casement, S.; Lillie, C.; Schattenburg, M.; Bautz, M.; Holland, A.; Tsunemi, H.; O'Dell, S.

2011-09-01

The x-ray astronomy community has never flown a celestial source spectrograph that can resolve natural line widths in absorption the way the ultraviolet community did with OAO-3 Copernicus back in 1972. Yet there is important science to be mined there, and right now, the large flagship missions like the International X-ray Observatory are not progressing toward launch. WHIMEx is an Explorer concept proposed earlier this year to open up that science regime in the next few years. The concept features a modified off-plane grating spectrograph design that will support high resolution (λ/δλ ~ 4000) in the soft x-ray band with a high packing density that will enable a modest cost space mission. We discuss the design and capabilities for the WHIMEx mission. Its prime science goal is detecting high temperature oxygen in the Intergalactic Medium, but it has a broad range of science potential cutting across all of x-ray astronomy and should give us a new window on the Universe.

Kinematics of Ultra-high-velocity Gas in the Expanding Molecular Shell Adjacent to the W44 Supernova Remnant

NASA Astrophysics Data System (ADS)

Yamada, Masaya; Oka, Tomoharu; Takekawa, Shunya; Iwata, Yuhei; Tsujimoto, Shiho; Tokuyama, Sekito; Furusawa, Maiko; Tanabe, Keisuke; Nomura, Mariko

2017-01-01

We mapped the ultra-high-velocity feature (the “Bullet”) detected in the expanding molecular shell associated with the W44 supernova remnant using the Nobeyama Radio Observatory 45 m telescope and the Atacama Submillimeter Telescope Experiment 10 m telescope. The Bullet clearly appears in the CO J = 1-0, CO J = 3-2, CO J = 4-3, and HCO+ J = 1-0 maps with a compact appearance (0.5 × 0.8 pc2) and an extremely broad-velocity width (ΔV ≃ 100 km s-1). The line intensities indicate that the Bullet has a higher density and temperature than those in the expanding molecular shell. The kinetic energy of the Bullet amounts to 1048.0 erg, which is approximately 1.5 orders of magnitude greater than the kinetic energy shared to the small solid angle of it. Two possible formation scenarios with an inactive isolated black hole are presented.

Nuclear structure beyond the neutron drip line. The lowest energy states in 9He via their T=5/2 isobaric analogs in 9Li

DOE PAGES

Uberseder, E.; Rogachev, G. V.; Goldberg, V. Z.; ...

2016-03-01

The level structure of the very neutron rich and unbound 9He nucleus has been the subject of significant experimental and theoretical study. Many recent works have claimed that the two lowest energy 9He states exist with spins J π=1/2 +and Jπ=1/2 -and widths on the order of 100–200 keV. These find-ings cannot be reconciled with our contemporary understanding of nuclear structure. Our present work is the first high-resolution study with low statistical uncertainty of the relevant excitation energy range in the 8He+n system, performed via a search for the T =5/2 isobaric analog states in 9Li populated through 8He+p elasticmore » scattering. Moreover, the present data show no indication of any narrow structures. Instead, we find evidence for a broad J π=1/2 +state in 9He located approximately 3 MeV above the neutron decay threshold.« less

Observations of Enhanced Radar Backscatter (ERB) from Millstone Hill

NASA Technical Reports Server (NTRS)

Lee, M. C.

1991-01-01

Intense enhancements of the incoherent radar backscatter spectrum from the topside ionosphere were observed with the Millstone Hill UHF radar. Enhancements occurring at the local ion acoustic frequency causing large asymmetries in the measured ion line may be produced by current driven instabilities. These enhancements pose a practical problem for space surveillance systems because their cross section and spectral width are characteristic of satellites. Conversely, their hard target signature complicates the study of naturally occurring ERB events; it is nearly impossible to distinguish them from satellites based on a single measurement. Statistical comparisons of observed coherent echo distributions with predictions from a satellite catalog were used to broadly identify periods of ERB activity. A series of experiments using multiple diagnostics, including satellite instruments, for simultaneous observations have established the association of ERB with large fluxes of soft suprathermal electrons carrying field aligned currents. Zenith data are also presented which show the asymmetric growth of ion acoustic waves directly above Millstone Hill. Details of these results are presented.

Venus - Limited extension and volcanism along zones of lithospheric weakness

NASA Technical Reports Server (NTRS)

Schaber, G. G.

1982-01-01

Three global-scale zones of possible tectonic origin are described as occurring along broad, low rises within the Equatorial Highlands on Venus (lat 50 deg N to 50 deg S, long 60 deg to 310 deg). The two longest of these tectonic zones, the Aphrodite-Beta and Themis-Atla zones, extend for 21,000 and 14,000 km, respectively. Several lines of evidence indicate that Beta and Atla Regiones, located at the only two intersections of the three major tectonic zones, are dynamically supported volcanic terranes associated with currently active volcanism. Rift valleys south of Aphrodite Terra and between Beta and Phoebe Regiones are characterized by 75- to 100-km widths, raised rims, and extensions of only a few tens of kilometers, about the same magnitudes as in continental rifts on the earth. Horizontal extension on Venus was probably restricted by an early choking-off of plate motion by high crustal and upper-mantle temperatures, and the subsequent loss of water and an asthenosphere.

On the impact of fjord geometry on grounding line stability

NASA Astrophysics Data System (ADS)

Åkesson, H.; Nick, F. M.; Morlighem, M.; Nisancioglu, K. H.

2016-12-01

Observations and reconstructions of Antarctic and Greenland marine-terminating glaciers and their grounding lines show that their response to external forcings is highly dependent on the geometry of individual glaciers, such as fjord geometry. While recent retreat of these glaciers is broadly consistent with warmer atmospheric and oceanic conditions, we observe considerable spatial and temporal variability, with diverse glacier behavior within the same regions. The relatively short observational record of marine-terminating glaciers also needs to be placed in a long-term context. Reconstructions of marine-terminating glaciers, however, indicate highly asynchronous retreat histories despite being subject to similar climatic forcings. These lines of evidence suggest that regional climate forcing alone cannot explain marine-terminating glacier behavior, and that these glaciers cannot be used uncritically as indicators of past climates because of their heterogeneous response to climate change. Here we use a dynamic flowline model with a physical treatment of iceberg calving to assess the effect of fjord geometry on grounding line stability on decadal and longer time scales. The model includes driving and resistive stresses of ice flow and is applied to idealized fjord geometries representing different real-world glaciers. We find that the geometry can override the signal from the ambient forcing over multiple centuries, resulting in non-linear, rapid grounding line migration. In particular we highlight the importance of fjord width, which has received relatively little attention in terms of marine ice sheet instability. Our findings provide new insights into grounding line behavior and may explain some of the documented heterogeneous, asynchronous patterns of marine-terminating glaciers in Greenland, Antarctica, Alaska and elsewhere. Further, we investigate the geometric influence on the reversibility and hysteresis of grounding line migration, relevant for oscillatory glacier behavior, marine-terminating glacier retreat-advance cycles and Heinrich events. Finally, we present comparative, preliminary results using the 3-dimensional ice sheet model ISSM and discuss our findings in terms of ice shelf stability and buttressing.

VLT/X-shooter observations of the low-metallicity blue compact dwarf galaxy PHL 293B including a luminous blue variable star

NASA Astrophysics Data System (ADS)

Izotov, Y. I.; Guseva, N. G.; Fricke, K. J.; Henkel, C.

2011-09-01

Context. We present VLT/X-shooter spectroscopic observations in the wavelength range λλ3000-23 000 Å of the extremely metal-deficient blue compact dwarf (BCD) galaxy PHL 293B containing a luminous blue variable (LBV) star and compare them with previous data. Aims: This BCD is one of the two lowest-metallicity galaxies where LBV stars were detected, allowing us to study the LBV phenomenon in the extremely low metallicity regime. Methods: We determine abundances of nitrogen, oxygen, neon, sulfur, argon, and iron by analyzing the fluxes of narrow components of the emission lines using empirical methods and study the properties of the LBV from the fluxes and widths of broad emission lines. Results: We derive an interstellar oxygen abundance of 12+log O/H = 7.71 ± 0.02, which is in agreement with previous determinations. The observed fluxes of narrow Balmer, Paschen and Brackett hydrogen lines correspond to the theoretical recombination values after correction for extinction with a single value C(Hβ) = 0.225. This implies that the star-forming region observed in the optical range is the only source of ionisation and there is no additional source of ionisation that is seen in the NIR range but is hidden in the optical range. We detect three v = 1-0 vibrational lines of molecular hydrogen. Their flux ratios and non-detection of v = 2-1 and 3-1 emission lines suggest that collisional excitation is the main source producing H2 lines. For the LBV star in PHL 293B we find broad emission with P Cygni profiles in several Balmer hydrogen emission lines and for the first time in several Paschen hydrogen lines and in several He i emission lines, implying temporal evolution of the LBV on a time scale of 8 years. The Hα luminosity of the LBV star is by one order of magnitude higher than the one obtained for the LBV star in NGC 2363 ≡ Mrk 71 which has a slightly higher metallicity 12+logO/H = 7.87. The terminal velocity of the stellar wind in the low-metallicity LBV of PHL293B is high, ~800 km s-1, and is comparable to that seen in spectra of some extragalactic LBVs during outbursts. We find that the averaged terminal velocities derived from the Paschen and He i emission lines are by some ~40-60 km s-1 lower than those derived from the Balmer emission lines. This probably indicates the presence of the wind accelerating outward. Based on observations collected at the European Southern Observatory, Chile, ESO program 60.A-9442(A).The reduced data in Figures 1 and 2 are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/533/A25

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

NASA Astrophysics Data System (ADS)

Aoki, Kentaro

2010-10-01

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

Structure of sunspot light bridges in the chromosphere and transition region

NASA Astrophysics Data System (ADS)

Rezaei, R.

2018-01-01

Context. Light bridges (LBs) are elongated structures with enhanced intensity embedded in sunspot umbra and pores. Aims: We studied the properties of a sample of 60 LBs observed with the Interface Region Imaging Spectrograph (IRIS). Methods: Using IRIS near- and far-ultraviolet spectra, we measured the line intensity, width, and Doppler shift; followed traces of LBs in the chromosphere and transition region (TR); and compared LB parameters with umbra and quiet Sun. Results: There is a systematic emission enhancement in LBs compared to nearby umbra from the photosphere up to the TR. Light bridges are systematically displaced toward the solar limb at higher layers: the amount of the displacement at one solar radius compares well with the typical height of the chromosphere and TR. The intensity of the LB sample compared to the umbra sample peaks at the middle/upper chromosphere where they are almost permanently bright. Spectral lines emerging from the LBs are broader than the nearby umbra. The systematic redshift of the Si IV line in the LB sample is reduced compared to the quiet Sun sample. We found a significant correlation between the line width of ions arising at temperatures from 3 × 104 to 1.5 × 105 K as there is also a strong spatial correlation among the line and continuum intensities. In addition, the intensity-line width relation holds for all spectral lines in this study. The correlations indicate that the cool and hot plasma in LBs are coupled. Conclusions: Light bridges comprise multi-temperature and multi-disciplinary structures extending up to the TR. Diverse heating sources supply the energy and momentum to different layers, resulting in distinct dynamics in the photosphere, chromosphere, and TR.

The abundance of interstellar sulphur and zinc in high density sight-lines

NASA Technical Reports Server (NTRS)

Harris, A. W.; Mashesse, J. M.

1986-01-01

On the basis of early absorption line studies of individual lines of sight with the Copernicus satellite, chlorine, sulphur and zinc were classed together as elements which showed little or no depletion, relative to hydrogen, in the interstellar medium. The abundances of other less volatile elements, such as Fe and Mg were found to vary widely from one sight-line to another with gas-phase abundances in some cases being orders of magnitude below their solar counterparts. Detailed studies are reported of the depletion/density behavior of two other volatile elements which were previously considered to be virtually undepleted, S and Zn, using equivalent width data from both Copernicus and IUE observations. The results provide further evidence that the established dependence of depletion on n bar (H) extends to volatile elements and show that their use as tracers of metallicity, or for estimating hydrogen column densities, may lead to large errors in sight-lines through dense regions. It now appears that such elements may take part in the surface chemistry of grains and be important constituents of grain mantle material, although they probably do not contribute significantly to the bulk mass of grains. Due to the very similar atomic masses and ionization potentials of sulphur and phosphorous, the thermal velocity distributions of the singly ionized species of these elements in interstellar clouds should be very similar. However, a comparison of Doppler widths (b-values) derived for SIT and PIT in the same sight-lines from the Bohlin et al Copernicus equivalent width measurements has revealed an unexpected systematic discrepancy of a factor of approx. 1.7. This Discrepancy indicates that the normally adopted oscillators strengths of the PII lambda lambda 1153 and 1302 A lines may require revision.

Very narrow band model calculations of atmospheric fluxes and cooling rates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernstein, L.S.; Berk, A.; Acharya, P.K.

1996-10-15

A new very narrow band model (VNBM) approach has been developed and incorporated into the MODTRAN atmospheric transmittance-radiance code. The VNBM includes a computational spectral resolution of 1 cm{sup {minus}1}, a single-line Voigt equivalent width formalism that is based on the Rodgers-Williams approximation and accounts for the finite spectral width of the interval, explicit consideration of line tails, a statistical line overlap correction, a new sublayer integration approach that treats the effect of the sublayer temperature gradient on the path radiance, and the Curtis-Godson (CG) approximation for inhomogeneous paths. A modified procedure for determining the line density parameter 1/d ismore » introduced, which reduces its magnitude. This results in a partial correction of the VNBM tendency to overestimate the interval equivalent widths. The standard two parameter CG approximation is used for H{sub 2}O and CO{sub 2}, while the Goody three parameter CG approximation is used for O{sub 3}. Atmospheric flux and cooling rate predictions using a research version of MODTRAN, MODR, are presented for H{sub 2}O (with and without the continuum), CO{sub 2}, and O{sub 3} for several model atmospheres. The effect of doubling the CO{sub 2} concentration is also considered. These calculations are compared to line-by-line (LBL) model calculations using the AER, GLA, GFDL, and GISS codes. The MODR predictions fall within the spread of the LBL results. The effects of decreasing the band model spectral resolution are illustrated using CO{sub 2} cooling rate and flux calculations. 36 refs., 18 figs., 1 tab.« less

Radiation-hydrodynamical simulations of massive star formation using Monte Carlo radiative transfer - II. The formation of a 25 solar-mass star

NASA Astrophysics Data System (ADS)

Harries, Tim J.; Douglas, Tom A.; Ali, Ahmad

2017-11-01

We present a numerical simulation of the formation of a massive star using Monte Carlo-based radiation hydrodynamics (RHD). The star forms via stochastic disc accretion and produces fast, radiation-driven bipolar cavities. We find that the evolution of the infall rate (considered to be the mass flux across a 1500 au spherical boundary) and the accretion rate on to the protostar, are broadly consistent with observational constraints. After 35 kyr the star has a mass of 25 M⊙ and is surrounded by a disc of mass 7 M⊙ and 1500 au radius, and we find that the velocity field of the disc is close to Keplerian. Once again these results are consistent with those from recent high-resolution studies of discs around forming massive stars. Synthetic imaging of the RHD model shows good agreement with observations in the near- and far-IR, but may be in conflict with observations that suggest that massive young stellar objects are typically circularly symmetric in the sky at 24.5 μm. Molecular line simulations of a CH3CN transition compare well with observations in terms of surface brightness and line width, and indicate that it should be possible to reliably extract the protostellar mass from such observations.

Structural investigation of new vanadium-bismuth-phosphate glasses by IR and ESR spectroscopy

NASA Astrophysics Data System (ADS)

Vedeanu, N.; Cozar, O.; Stanescu, R.; Cozar, I. B.; Ardelean, I.

2013-07-01

IR spectra changes of the xV2O5(1 - x)[0.8P2O5ṡ0.2Bi2O3] glass system with 0 ⩽ x ⩽ 50 mol% show that vanadium oxide acts as a network modifier at low concentration (x ⩽ 5 mol%), affecting especially the Bi2O3 network. In the same time the phosphate groups (structures) impose their presence by themselves, fact which is illustrated by the increasing of the intensity of characteristic 910, 1040, 1230 cm-1 bands. The IR bands belonging to the phosphate groups are strongly reduced for x ⩾ 10 mol% due to the phosphate network depolymerization and to the appearance of new vibrations characteristic for POV and VOV linkages, showing the network former role of V2O5. In the same time the changes observed in the ESR spectra of these glasses are explained supposing the superposition of two signals, one with a well-resolved hyperfine structure typical for isolated V4+ ions and a broad line characteristic for clustered ions. The line width dependence versus V2O5 content shows that dipole-dipole interactions exist between vanadium ions until x = 5 mol% and the superexchange interactions prevail at high content (x ⩾ 10 mol%).

VizieR Online Data Catalog: NGC 4038/4039 broad and /narrow band photometry (Mengel+, 2005)

NASA Astrophysics Data System (ADS)

Mengel, S.; Lehnert, M. D.; Thatte, N.; Genzel, R.

2005-06-01

The Ks-band image which was used for the 3{sigma}-detection was obtained with ISAAC on VLT-ANTU as part of programme 65.N-0577, and has a FWHM of ~0.38". 1072 point-like objects were detected. For the multi-band photometry, we also used the HST archival images obtained by Whitmore et al. (see Whitmore et al., 1999AJ....118.1551W), which we rebinned to the same pixel size as the ISAAC image (0.1484"/pix). The CO narrow band image was also obtained with ISAAC, while the Br{gamma} image was obtained with SOFI at the NTT (programme number 63.N-0528). The Br{gamma} image had a lower image quality than the other two images (FWHM=0.7"). The photometry data were used to simultaneously fit age and extinction for each individual cluster in comparison to an evolutionary synthesis model. Where possible, the visual extinction was determined from an average of the extinction from the broadband fit and from the Hydrogen recombination line ratios (in comparison to the expected Case B line ratio). The age estimate from the fit was, where possible, averaged with the aged determined from equivalent widths and CO index. (1 data file).

Adolescent Black Holes May be Hard to Find

NASA Astrophysics Data System (ADS)

Elvis, Martin; Chakravorty, Susmita

2017-08-01

Finding adolescent black holes that are growing rapidly from their seed masses is a major goal of the next generation of large observatories. We have examined how these early quasars may appear in terms of their broad emission lines (BELs) in the optical and ultraviolet. We find that below 10**6 Msol, the equivalent widths of the BELs drop precipitously. Moreover, if the BELs originate in clouds that form as the cool phase of a multi-phase medium, then for metallicities Z/Zsol ~< 3, the thermal instabilities that create them will not exist. However, in observed quasars at high redshift Z/Zsol is >> 3, so quasars are preferentially found in special environments, perhaps with deep potential wells. The population that we see though could be biased by the Z/Zsol > 3 requirement. A stronger argument is that the thermal instability leading to cool clouds is predominantly due to line emission by iron. Iron comes primarily from type 1a supernovae, which take of order 1 billion years to ignite. Hence iron should be under-abundant relative to other elements until z ~ 6 - 7. That the highest redshift quasar is at z = 7.1 may be a consequence of this requirement. Quasars above z ~ 7 could still be found by their rest-frame ultraviolet or X-ray continuum.

Metabolic Profiling and Physiological Analysis of a Novel Rice Introgression Line with Broad Leaf Size

PubMed Central

Zhao, Xiuqin; Zhang, Guilian; Wang, Yun; Zhang, Fan; Wang, Wensheng; Zhang, Wenhao; Fu, Binying; Xu, Jianlong; Li, Zhikang

2015-01-01

A rice introgression line, NIL-SS1, and its recurrent parent, Teqing, were used to investigate the influence of the introgression segment on plant growth. The current research showed NIL-SS1 had an increased flag leaf width, total leaf area, spikelet number per panicle and grain yield, but a decreased photosynthetic rate. The metabolite differences in NIL-SS1 and Teqing at different developmental stages were assessed using gas chromatography—mass spectrometry technology. Significant metabolite differences were observed across the different stages. NIL-SS1 increased the plant leaf nitrogen content, and the greatest differences between NIL-SS1 and Teqing occurred at the booting stage. Compared to Teqing, the metabolic phenotype of NIL-SS1 at the booting stage has closer association with those at the flowering stage. The introgression segment induced more active competition for sugars and organic acids (OAs) from leaves to the growing young spikes, which resulted in more spikelet number per plant (SNP). The results indicated the introgression segment could improve rice grain yield by increasing the SNP and total leaf area per plant, which resulted from the higher plant nitrogen content across growth stages and stronger competition for sugars and OAs of young spikes at the booting stage. PMID:26713754

Calculation of correlation times for the. gamma. -alumina-supported molybdenum subcarbonyl, Mo(CO) sub 3 (ads)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagner, G.W.; Hanson, B.E.

1989-07-05

The theory of carbon-13 NMR line widths in the solid state for molecules with large chemical shift anisotropies is applied to the adsorbed molybdenum subcarbonyls Mo(CO){sub 3}(ads) and Mo(CO){sub 5}(ads). Correlation times for the rotation of the molybdenum subcarbonyl groups Mo(CO){sub 3}(ads) and Mo(CO){sub 5}(ads) on partially dehydroxylated alumina are calculated. Good agreement is obtained between data reported at observation frequencies of 15 to 75.5 MHz for carbon-13 for Mo(CO){sub 3}(ads). The correlation time for this adsorbed species is calculated to have a lower limit of 4.6 {plus minus} 0.5 ms. The presence of broad lines in the room temperaturemore » spectra for Mo(CO){sub 3}(ads) is thus explained by a slow molecular motion. Data for Mo(CO){sub 5}(ads) are available at observation frequencies of 15 to 90.5 MHz. A good fit to the experimental data is obtained assuming either long or short correlation times for this species. Thus literature estimates of <10{sup {minus}6}s for the correlation time for this species cannot be confirmed with certainty from the analysis presented here.« less

Feedback in the Antennae Galaxies (NGC 4038/9): I. High-Resolution Infrared Spectroscopy of Winds from Super Star Clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gilbert, A; Graham, J

2007-06-05

We present high-resolution (R {approx} 24,600) near-IR spectroscopy of the youngest super star clusters (SSCs) in the prototypical starburst merger, the Antennae Galaxies. These SSCs are young (3-7 Myr old) and massive (10{sup 5}-10{sup 7} M{sub {circle_dot}} for a Kroupa IMF) and their spectra are characterized by broad, extended Brackett {gamma} emission, so we refer to them as emission-line clusters (ELCs) to distinguish them from older SSCs. The Br {gamma} lines of most ELCs have supersonic widths (60-110 km s{sup -1} FWHM) and non-Gaussian wings whose velocities exceed the clusters escape velocities. This high-velocity unbound gas is flowing out inmore » winds that are powered by the clusters massive O and W-R stars over the course of at least several crossing times. The large sizes of some ELCs relative to those of older SSCs may be due to expansion caused by these outflows; many of the ELCs may not survive as bound stellar systems, but rather dissipate rapidly into the field population. The observed tendency of older ELCs to be more compact than young ones is consistent with the preferential survival of the most concentrated clusters at a given age.« less

Ultraviolet Broad Absorption Features and the Spectral Energy Distribution of the QSO PG 1351+64. 3.1

NASA Technical Reports Server (NTRS)

Zheng, W.; Kriss, G. A.; Wang, J. X.; Brotherton, M.; Oegerle, W. R.; Blair, W. P.; Davidsen, A. F.; Green, R. F.; Hutchings, J. B.; Kaiser, M. E.;

Ultraviolet Broad Absorption Features and the Spectral Energy Distribution of the QSO PG 1351+641. 2.5

NASA Technical Reports Server (NTRS)

Zheng, W.; Kriss, G. A.; Wang, J. X.; Brotherton, M.; Oegerle, W. R.; Blair, W. P.; Davidsen, A. F.; Green, R. F.; Hutchings, J. B.; Kaiser, M. E.;

75 FR 3486 - Susquehanna to Roseland 500kV Transmission Line, Environmental Impact Statement, Delaware Water...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-21

... connection with the Susquehanna to Roseland 500kV Transmission Line. SUMMARY: Pursuant to National... Recreational River, and Appalachian National Scenic Trail, in connection with the proposed Susquehanna (Berwick... expand the width of the transmission line right-of-way beyond the Applicant's current holdings. The...

Line intersect sampling: Ell-shaped transects and multiple intersections

Treesearch

Timothy G. Gregoire; Harry T. Valentine

2003-01-01

The probability of selecting a population element under line intersect sampling depends on the width of the particle in the direction perpendicular to the transect, as is well known. The consequence of this when using ell-shaped transects rather than straight-line transects are explicated, and modifications that preserve design-unbiasedness of Kaiser's (1983)...

29 CFR 1917.16 - Line handling. (See also § 1917.95(b)).

Code of Federal Regulations, 2011 CFR

2011-07-01

... also § 1917.95(b)). (a) In order to provide safe access for handling lines while mooring and unmooring... be used. (b) When stringpiece or apron width is insufficient for safe footing, grab lines or rails... the water edge of a berth and a shed or other structure.) ...

29 CFR 1917.16 - Line handling. (See also § 1917.95(b)).

Code of Federal Regulations, 2010 CFR

2010-07-01

... also § 1917.95(b)). (a) In order to provide safe access for handling lines while mooring and unmooring... be used. (b) When stringpiece or apron width is insufficient for safe footing, grab lines or rails... the water edge of a berth and a shed or other structure.) ...

The analysis of ensembles of moderately saturated interstellar lines

NASA Technical Reports Server (NTRS)

Jenkins, E. B.

1986-01-01

It is shown that the combined equivalent widths for a large population of Gaussian-like interstellar line components, each with different central optical depths tau(0) and velocity dispersions b, exhibit a curve of growth (COG) which closely mimics that of a single, pure Gaussian distribution in velocity. Two parametric distributions functions for the line populations are considered: a bivariate Gaussian for tau(0) and b and a power law distribution for tau(0) combined with a Gaussian dispersion for b. First, COGs for populations having an extremely large number of nonoverlapping components are derived, and the implications are shown by focusing on the doublet-ratio analysis for a pair of lines whose f-values differ by a factor of two. The consequences of having, instead of an almost infinite number of lines, a relatively small collection of components added together for each member of a doublet are examined. The theory of how the equivalent widths grow for populations of overlapping Gaussian profiles is developed. Examples of the composite COG analysis applied to existing collections of high-resolution interstellar line data are presented.

Spectroscopic Results From Blue Hills Observatory of the 2009-2011 Eclipse of epsilon Aurigae

NASA Astrophysics Data System (ADS)

Gorodenski, S. A.

2012-02-01

The purpose of this paper is to report spectroscopic results of epsilon Aurigae during the 2009-2011 eclipse. Spectra of the sodium D lines and an absorption line occurring at approximately 5853Å were taken from February 13, 2010, to October 10, 2011, with an LHIRES III spectrograph and a 16-inch Meade telescope at Blue Hills Observatory in Dewey, Arizona. Equivalent width and radial velocity data support the presence of a void or ring structure within the eclipsing disk, and they support a central disk clearing around an unseen primary central object. The results also indicate the disk does not end at fourth contact but continues for a significant distance. Analysis of radial velocities demonstrated the profile of the 5853Å line has a disk component in addition to the primary F0 star component. A split line at this location was observed. From the equivalent width profile of the 5853Å line the duration of the split line event was estimated to be 101 days. Other lesser results are presented and discussed.

VizieR Online Data Catalog: Spectroscopic survey of youngest field stars II. (Frasca+, 2018)

NASA Astrophysics Data System (ADS)

Frasca, A.; Guillout, P.; Klutsch, A.; Freire Ferrero, R.; Marilli, E.; Biazzo, K.; Gandolfi, D.; Montes, D.

2018-01-01

Radial velocity (RV) and projected rotational velocity (vsini) of the single stars and SB1 systems are quoted in Table A1 along with the V magnitude and B-V color index. The vsini values measured from the full width at half maximum of the of the cross-correlation function (CCF) and by means of the code ROTFIT are both listed in Table A1. Table A2 and A3 report RV and vsini from the CCF for the components of SB2 and triple (SB3) systems, respectively. Table A4 reports, for the single stars and SB1 systems, the spectral type, atmospheric parameters (Teff, logg, and [Fe/H]), the equivalent width of the lithium 6708-A line (corrected for the FeI blends) and the net equivalent width of Hα line, measured after the subtraction of the inactive photospheric template. (4 data files).

Thermal Boundary Layer Effects on Line-of-Sight Tunable Diode Laser Absorption Spectroscopy (TDLAS) Gas Concentration Measurements.

PubMed

Qu, Zhechao; Werhahn, Olav; Ebert, Volker

2018-06-01

The effects of thermal boundary layers on tunable diode laser absorption spectroscopy (TDLAS) measurement results must be quantified when using the line-of-sight (LOS) TDLAS under conditions with spatial temperature gradient. In this paper, a new methodology based on spectral simulation is presented quantifying the LOS TDLAS measurement deviation under conditions with thermal boundary layers. The effects of different temperature gradients and thermal boundary layer thickness on spectral collisional widths and gas concentration measurements are quantified. A CO 2 TDLAS spectrometer, which has two gas cells to generate the spatial temperature gradients, was employed to validate the simulation results. The measured deviations and LOS averaged collisional widths are in very good agreement with the simulated results for conditions with different temperature gradients. We demonstrate quantification of thermal boundary layers' thickness with proposed method by exploitation of the LOS averaged the collisional width of the path-integrated spectrum.

Thin Line, Broad Shadows

NASA Image and Video Library

2011-02-21

Saturn rings appear as only a thin line seen edge-on in the middle of this view from NASA Cassini spacecraft, but the rings cast broad shadows on the southern hemisphere of the planet in the lower left of the image.

Air-photo based change in channel width in the Minnesota River basin: Modes of adjustment and implications for sediment budget

NASA Astrophysics Data System (ADS)

Wesley Lauer, J.; Echterling, Caitlyn; Lenhart, Christian; Belmont, Patrick; Rausch, Rachel

2017-11-01

The Minnesota River and major tributaries have experienced large increases in discharge over the past century. Aerial photograph-based measurements of channel width were made for the 1938-2015 period at 16 multibend subreaches by digitizing the area between vegetation lines and dividing by centerline length. Results show considerable increases in width for the main stem (0.62 ± 0.10%/y) and major tributaries (0.31 ± 0.08%/y) but are inconclusive for smaller channels (width < 25 m). Width change for a 146.5-km reach of the lower Minnesota River between 1938 and 2008 is similar to that from the subreach-scale analysis. Widening was associated with lateral centerline movement and temporal change in at-a-station hydraulic geometry for water surface width, indicating that widening is associated with cross-sectional change and not simply upward movement of the vegetation line. Digital elevation model analysis and regional hydraulic geometry show that the main stem and larger tributaries account for the vast majority ( 85%) of bankfull channel volume. High-order channels are thus disproportionately responsible for sediment production through cross section enlargement, although floodplains or off-channel water bodies adjacent to these channels likely represent important sediment sinks. Because channel enlargement can play an important role in sediment production, it should be considered in sediment reduction strategies in the Minnesota River basin and carefully evaluated in other watersheds undergoing long-term increases in discharge.

Variation in the Water and Ammonia Abundance in Jupiter’s North Equatorial Belt

NASA Astrophysics Data System (ADS)

Bjoraker, Gordon L.; de Pater, Imke; Wong, Michael H.; Adamkovics, Mate; Hewagama, Tilak; Orton, Glenn

2017-10-01

We used iSHELL on NASA’s Infrared Telescope Facility and NIRSPEC on the Keck telescope concurrent with Juno perijoves 4-6 between February and May 2017 to obtain 5-micron spectra of Jupiter. Here we will focus on observations of the North Equatorial Belt. Spectrally resolved line profiles of CH3D, NH3, and H2O probe the 1 to 8-bar level of Jupiter’s troposphere. This overlaps with the weighting functions for several channels of Juno’s microwave radiometer. The profile of the CH3D lines at 4.66 microns is very broad in Hot Spots due to collisions with up to 8 bars of H2, where unit optical depth occurs due to collision-induced H2 opacity. The extreme width of these CH3D features implies that the Hot Spots that we observed do not have significant cloud opacity for P > 2 bars. We will discuss the abundance of NH3 and gaseous H2O within Hot Spots and other regions near the longitude of perijove for each Juno encounter. We had dry nights on Mauna Kea and a sufficient Doppler shift to detect H2O. We will compare line wings to derive H2O profiles in the 2 to 6-bar region. NEB Hot Spots are depleted in NH3 with respect to adjacent regions, especially for P < 2 bars. NEB Hot Spots are highly depleted in H2O for P < 5 bars.

Water and Ammonia Abundances in Jupiter's South Equatorial Belt and Equatorial Zone at the time of Juno Perijoves 4 to 6

NASA Astrophysics Data System (ADS)

Bjoraker, G. L.; De Pater, I.; Wong, M. H.; Adamkovics, M.; Hewagama, T.; Orton, G.

2017-12-01

We used iSHELL on NASA's Infrared Telescope Facility and NIRSPEC on the Keck telescope concurrent with Juno perijoves 4-6 between February and May 2017 to obtain 5-micron spectra of Jupiter. Here we will focus on observations of the South Equatorial Belt and the Equatorial Zone. Spectrally resolved line profiles of CH3D, NH3, and H2O probe the 1 to 8-bar level of Jupiter's troposphere. This overlaps with the weighting functions for several channels of Juno's microwave radiometer. The profile of the CH3D lines at 4.66 microns is very broad in SEB Hot Spots due to collisions with up to 8 bars of H2, where unit optical depth occurs due to collision-induced H2 opacity. The extreme width of these CH3D features implies that the Hot Spots that we observed do not have significant cloud opacity for P > 2 bars. We will discuss the abundance of NH3 and gaseous H2O within SEB Hot Spots and other regions near the longitude of perijove for each Juno encounter. We had dry nights on Mauna Kea and a sufficient Doppler shift to detect H2O. We will compare line wings to derive H2O profiles in the 2 to 6-bar region. SEB Hot Spots are highly depleted in H2O for P < 5 bars with respect to zones.

1H line width dependence on MAS speed in solid state NMR - Comparison of experiment and simulation

NASA Astrophysics Data System (ADS)

Sternberg, Ulrich; Witter, Raiker; Kuprov, Ilya; Lamley, Jonathan M.; Oss, Andres; Lewandowski, Józef R.; Samoson, Ago

2018-06-01

Recent developments in magic angle spinning (MAS) technology permit spinning frequencies of ≥100 kHz. We examine the effect of such fast MAS rates upon nuclear magnetic resonance proton line widths in the multi-spin system of β-Asp-Ala crystal. We perform powder pattern simulations employing Fokker-Plank approach with periodic boundary conditions and 1H-chemical shift tensors calculated using the bond polarization theory. The theoretical predictions mirror well the experimental results. Both approaches demonstrate that homogeneous broadening has a linear-quadratic dependency on the inverse of the MAS spinning frequency and that, at the faster end of the spinning frequencies, the residual spectral line broadening becomes dominated by chemical shift distributions and susceptibility effects even for crystalline systems.

Ab initio non-adiabatic study of the 4pσ B'' 1Σ+u state of H2

NASA Astrophysics Data System (ADS)

Glass-Maujean, M.; Schmoranzer, H.

2018-05-01

Fully ab initio non-adiabatic multichannel quantum defect calculations of the 4pσ B'' 1∑u+ energy levels, line intensities and widths, based on the latest quantum-chemical clamped-nuclei calculations of Wolniewicz and collaborators are presented for H2. The B″ state corresponds to the inner well of the ? state. The B'' v ≥ 1 levels are rapidly predissociated through vibrational coupling with the 3pσ B' 1Σ+u continuum so that coupled-equation calculations become unstable. Multichannel quantum defect theory, on the other hand, is demonstrated to be particularly suited to this situation. Experimental data as level energies, line intensities and dissociation widths were revisited and corrected. Reinvestigating previously published spectra, several new lines were assigned.

Analysis of the 0.511 MeV radiation at the OSO-7 satellite. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Dunphy, P. P.

1974-01-01

Observations of the 0.511 MeV positron annihilation, gamma ray on the OSO-7 satellite are presented. Variables which affect the counting rate are discussed. An upper limit flux of .0076 photons/sq cm/sec is obtained for the quiet sun and a positive solar flux of .063(+ or - .0002) photons/sq cm/sec is obtained for the 3B flare of 4 August 1972. The width of this annihilation line gives an upper limit temperature for the annihilation region of approximately 6 million K. An analysis of the line width and position also shows that the contribution to the line from positronium annihilation is less than 100% at the 99% confidence level. An upper limit is also found for an isotropic cosmic flux.

Erratum: ``CO Line Width Differences in Early Universe Molecular Emission-Line Galaxies: Submillimeter Galaxies versus QSO Hosts'' (AJ, 131, 2763 [2006])

NASA Astrophysics Data System (ADS)

Carilli, C. L.; Wang, Ran

2006-11-01

It has been pointed out to us that in three dimensions the mean angle of randomly oriented disks with respect to the sky plane is <θ>=30deg, and not the 45° assumed in the original paper. This lower angle for the (assumed) random distribution of submillimeter galaxies, coupled with the factor of 2.3 lower mean CO line width for high-z, far-IR-luminous QSO host galaxies relative to the submillimeter galaxies, implies a mean angle with respect to the sky plane for the QSO host galaxies of <θ>QSO=13deg, as opposed to the 18° quoted in the original paper. We thank Pat Hall for bringing this to our attention.

Pinning of the Contact Line during Evaporation on Heterogeneous Surfaces: Slowdown or Temporary Immobilization? Insights from a Nanoscale Study.

PubMed

Zhang, Jianguo; Müller-Plathe, Florian; Leroy, Frédéric

2015-07-14

The question of the effect of surface heterogeneities on the evaporation of liquid droplets from solid surfaces is addressed through nonequilibrium molecular dynamics simulations. The mechanism behind contact line pinning which is still unclear is discussed in detail on the nanoscale. Model systems with the Lennard-Jones interaction potential were employed to study the evaporation of nanometer-sized cylindrical droplets from a flat surface. The heterogeneity of the surface was modeled through alternating stripes of equal width but two chemical types. The first type leads to a contact angle of 67°, and the other leads to a contact angle of 115°. The stripe width was varied between 2 and 20 liquid-particle diameters. On the surface with the narrowest stripes, evaporation occurred at constant contact angle as if the surface was homogeneous, with a value of the contact angle as predicted by the regular Cassie-Baxter equation. When the width was increased, the contact angle oscillated during evaporation between two boundaries whose values depend on the stripe width. The evaporation behavior was thus found to be a direct signature of the typical size of the surface heterogeneity domains. The contact angle both at equilibrium and during evaporation could be predicted from a local Cassie-Baxter equation in which the surface composition within a distance of seven fluid-particle diameters around the contact line was considered, confirming the local nature of the interactions that drive the wetting behavior of droplets. More importantly, we propose a nanoscale explanation of pinning during evaporation. Pinning should be interpreted as a drastic slowdown of the contact line dynamics rather than a complete immobilization of it during a transition between two contact angle boundaries.

ALMA Observations of a Quiescent Molecular Cloud in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Wong, Tony; Hughes, Annie; Tokuda, Kazuki; Indebetouw, Rémy; Bernard, Jean-Philippe; Onishi, Toshikazu; Wojciechowski, Evan; Bandurski, Jeffrey B.; Kawamura, Akiko; Roman-Duval, Julia; Cao, Yixian; Chen, C.-H. Rosie; Chu, You-hua; Cui, Chaoyue; Fukui, Yasuo; Montier, Ludovic; Muller, Erik; Ott, Juergen; Paradis, Deborah; Pineda, Jorge L.; Rosolowsky, Erik; Sewiło, Marta

2017-12-01

We present high-resolution (subparsec) observations of a giant molecular cloud in the nearest star-forming galaxy, the Large Magellanic Cloud. ALMA Band 6 observations trace the bulk of the molecular gas in 12CO(2-1) and the high column density regions in 13CO(2-1). Our target is a quiescent cloud (PGCC G282.98-32.40, which we refer to as the “Planck cold cloud” or PCC) in the southern outskirts of the galaxy where star formation activity is very low and largely confined to one location. We decompose the cloud into structures using a dendrogram and apply an identical analysis to matched-resolution cubes of the 30 Doradus molecular cloud (located near intense star formation) for comparison. Structures in the PCC exhibit roughly 10 times lower surface density and five times lower velocity dispersion than comparably sized structures in 30 Dor, underscoring the non-universality of molecular cloud properties. In both clouds, structures with relatively higher surface density lie closer to simple virial equilibrium, whereas lower surface-density structures tend to exhibit supervirial line widths. In the PCC, relatively high line widths are found in the vicinity of an infrared source whose properties are consistent with a luminous young stellar object. More generally, we find that the smallest resolved structures (“leaves”) of the dendrogram span close to the full range of line widths observed across all scales. As a result, while the bulk of the kinetic energy is found on the largest scales, the small-scale energetics tend to be dominated by only a few structures, leading to substantial scatter in observed size-line-width relationships.

Solar off-limb line widths: Alfvén waves, ion-cyclotron waves, and preferential heating

NASA Astrophysics Data System (ADS)

Dolla, L.; Solomon, J.

2008-05-01

Context: Alfvén waves and ion-cyclotron absorption of high-frequency waves are frequently brought into models devoted to coronal heating and fast solar-wind acceleration. Signatures of ion-cyclotron resonance have already been observed in situ in the solar wind (HELIOS spacecrafts) and, recently, in the upper corona (UVCS/SOHO remote-sensing results). Aims: We propose a method to constrain both the Alfvén wave amplitude and the preferential heating induced by ion-cyclotron resonance, above a partially developed polar coronal hole observed with the SUMER/SOHO spectrometer. Methods: The instrumental stray light contribution is first substracted from the spectra. By supposing that the non-thermal velocity is related to the Alfvén wave amplitude, it is constrained through a density diagnostic and the gradient of the width of the Mg X 625 Å line. The temperatures of several coronal ions, as functions of the distance above the limb, are then determined by substracting the non-thermal component to the observed line widths. Results: The effect of stray light explains the apparent decrease with height in the width of several spectral lines, this decrease usually starting about 0.1-0.2 R_⊙ above the limb. This result rules out any direct evidence of damping of the Alfvén waves, often suggested by other authors. We also find that the ions with the smallest charge-to-mass ratios are the hottest ones at a fixed altitude and that they are subject to a stronger heating, as compared to the others, between 57´´ and 102´´ above the limb. This constitutes a serious clue to ion-cyclotron preferential heating.

Area Judgment from Width and Height Information: The Case of the Rectangle.

ERIC Educational Resources Information Center

Mullet, Etienne; Rulence-Paques, Patricia

1998-01-01

Adults, 9-year olds, and 5-year olds were shown horizontal and vertical lines of various sizes, presented on same wall or different walls, and asked to estimate corresponding area. Responses indicated that when width and height were separated, children gave same weight to both dimensions while adults gave greater weight to larger dimensions; when…

Development of Elite BPH-Resistant Wide-Spectrum Restorer Lines for Three and Two Line Hybrid Rice.

PubMed

Fan, Fengfeng; Li, Nengwu; Chen, Yunping; Liu, Xingdan; Sun, Heng; Wang, Jie; He, Guangcun; Zhu, Yingguo; Li, Shaoqing

2017-01-01

Hybrid rice has contributed significantly to the world food security. Breeding of elite high-yield, strong-resistant broad-spectrum restorer line is an important strategy for hybrid rice in commercial breeding programs. Here, we developed three elite brown planthopper (BPH)-resistant wide-spectrum restorer lines by pyramiding big-panicle gene Gn8.1 , BPH-resistant genes Bph6 and Bph9 , fertility restorer genes Rf3, Rf4, Rf5 , and Rf6 through molecular marker assisted selection. Resistance analysis revealed that the newly developed restorer lines showed stronger BPH-resistance than any of the single-gene donor parent Luoyang-6 and Luoyang-9. Moreover, the three new restorer lines had broad spectrum recovery capabilities for Honglian CMS, Wild abortive CMS and two-line GMS sterile lines, and higher grain yields than that of the recurrent parent 9,311 under nature field conditions. Importantly, the hybrid crosses also showed good performance for grain yield and BPH-resistance. Thus, the development of elite BPH-resistant wide-spectrum restorer lines has a promising future for breeding of broad spectrum BPH-resistant high-yield varieties.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yu-Qian; Modjaz, Maryam; Bianco, Federica B., E-mail: YL1260@nyu.edu, E-mail: mmodjaz@nyu.edu

Super-luminous supernovae (SLSNe) are tremendously luminous explosions whose power sources and progenitors are highly debated. Broad-lined SNe Ic (SNe Ic-bl) are the only type of SNe that are connected with long-duration gamma-ray bursts (GRBs). Studying the spectral similarity and difference between the populations of hydrogen-poor SLSNe (SLSNe Ic) and of hydrogen-poor stripped-envelope core-collapse SNe, in particular SNe Ic and SNe Ic-bl, can provide crucial observations to test predictions of theories based on various power source models and progenitor models. In this paper, we collected all of the published optical spectra of 32 SLSNe Ic, 21 SNe Ic-bl, as well asmore » 17 SNe Ic, quantified their spectral features, constructed average spectra, and compared them in a systematic way using new tools we have developed. We find that SLSNe Ic and SNe Ic-bl, including those connected with GRBs, have comparable widths for their spectral features and average absorption velocities at all phases. Thus, our findings strengthen the connection between SLSNe Ic and GRBs. In particular, SLSNe Ic have average Fe ii λ 5169 absorption velocities of −15,000 ± 2600 km s{sup −1} at 10 days after peak, which are higher than those of SNe Ic by ∼7000 km s{sup −1} on average. SLSNe Ic also have significantly broader Fe ii λ 5169 lines than SNe Ic. Moreover, we find that such high absorption and width velocities of SLSNe Ic may be hard to explain with the interaction model, and none of the 13 SLSNe Ic with measured absorption velocities spanning over 10 days has a convincing flat velocity evolution, which is inconsistent with the magnetar model in one dimension. Lastly, we compare SN 2011kl, the first SN connected with an ultra-long GRB, with the mean spectrum of SLSNe Ic and of SNe Ic-bl.« less

Optimization of a Focusable and Rotatable Shear-Wave Periodic Permanent Magnet Electromagnetic Acoustic Transducers for Plates Inspection

PubMed Central

Qiu, Gongzhe

2017-01-01

Due to the symmetry of conventional periodic-permanent-magnet electromagnetic acoustic transducers (PPM EMATs), two shear (SH) waves can be generated and propagated simultaneously in opposite directions, which makes the signal recognition and interpretation complicatedly. Thus, this work presents a new SH wave PPM EMAT design, rotating the parallel line sources to realize the wave beam focusing in a single-direction. The theoretical model of distributed line sources was deduced firstly, and the effects of some parameters, such as the inner coil width, adjacent line sources spacing and the angle between parallel line sources, on SH wave focusing and directivity were studied mainly with the help of 3D FEM. Employing the proposed PPM EMATs, some experiments are carried out to verify the reliability of FEM simulation. The results indicate that rotating the parallel line sources can strength the wave on the closing side of line sources, decreasing the inner coil width and the adjacent line sources spacing can improve the amplitude and directivity of signals excited by transducers. Compared with traditional PPM EMATs, both the capacity of unidirectional excitation and directivity of the proposed PPM EMATs are improved significantly. PMID:29186790

H-α profile of M-type red giant stars by using astronomical spectroscopy technique

NASA Astrophysics Data System (ADS)

Saadon, Mohd Hafiz Mohd; Zainuddin, Mohd Zambri

2013-05-01

The technique of spectroscopy in astronomy is a research or a method which uses spectrum lines emitted by a body that emit electromagnetic ray. These lines will be used to determine the characteristics of any celestial body and one of the most dominant lines is H-α line. The research has been using 20RC Carbon Truss Ritchey-Chrétien telescope, SBIG Self Guided Spectrograph (SGS) with high resolution camera Couple-Charged Device CCD ST-7E. Since H-α line is to be found at 6562.817 Å, neon lamp is being used as calibration because of the obvious lines of this element is in the higher range of visible wavelength, from 5800 to 7500 Å. The software: TheSky and CCDSoft are being used for collecting and analyzing observed data while IRAF which being installed on LINUX interface are used to process the collected data. The data were processed to measure the full width half maximum (FHWM) and equivalent width (EW) for H-α line for each star. Seven M-type red giants that have been chosen are HD 80493, HD 148478, HD 39801, HD 112300, HD 101153, HD 156014 and HD 148783.

Optimization of a Focusable and Rotatable Shear-Wave Periodic Permanent Magnet Electromagnetic Acoustic Transducers for Plates Inspection.

PubMed

Song, Xiaochun; Qiu, Gongzhe

2017-11-24

Due to the symmetry of conventional periodic-permanent-magnet electromagnetic acoustic transducers (PPM EMATs), two shear (SH) waves can be generated and propagated simultaneously in opposite directions, which makes the signal recognition and interpretation complicatedly. Thus, this work presents a new SH wave PPM EMAT design, rotating the parallel line sources to realize the wave beam focusing in a single-direction. The theoretical model of distributed line sources was deduced firstly, and the effects of some parameters, such as the inner coil width, adjacent line sources spacing and the angle between parallel line sources, on SH wave focusing and directivity were studied mainly with the help of 3D FEM. Employing the proposed PPM EMATs, some experiments are carried out to verify the reliability of FEM simulation. The results indicate that rotating the parallel line sources can strength the wave on the closing side of line sources, decreasing the inner coil width and the adjacent line sources spacing can improve the amplitude and directivity of signals excited by transducers. Compared with traditional PPM EMATs, both the capacity of unidirectional excitation and directivity of the proposed PPM EMATs are improved significantly.

VizieR Online Data Catalog: RPA Southern Pilot Search of 107 Stars (Hansen+, 2018)

NASA Astrophysics Data System (ADS)

Hansen, T. T.; Holmbeck, E. M.; Beers, T. C.; Placco, V. M.; Roederer, I. U.; Frebel, A.; Sakari, C. M.; Simon, J. D.; Thompson, I. B.

2018-03-01

Complete equivalent width measurements of FeI and FeII lines for all stars in our sample used to derive spectroscopic stellar parameters. Also included are the derived abundances for each line. (2 data files).

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Espada, D.; Matsushita, S.; Sakamoto, K.

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-dishmore » 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.« less

Synthesis of resistive tapers to control scattering patterns of strips

NASA Astrophysics Data System (ADS)

Haupt, Randy L.

Scattering occurs when an electromagnetic wave impinges on an object and creates currents in that object which reradiate other electromagnetic waves. Three primary methods exist to reduce microwave scattering from an object: covering it with absorber, changing its shape, and detuning it through impedance loading. Absorbers convert unwanted electromagnetic energy into heat. An example is lining an anechoic chamber with absorbers. Changing its shape channels energy from one direction to another, changes dominant scattering centers, or causes returns from one direction to another, changes dominant scattering centers, or causes returns from various parts to coherently add and cancel the total return. Impedance loading alters the resonant frequency of an object. Absorbers have the most attractive features. They have a broad bandwidth, attenuate the return in many directions, and may be used to reduce scattering from an object after the object is designed. Before trying to control scattering from complex shapes, such as an antenna or airplane, one should try to develop methods to control scattering from simple objects. A very simple object is two dimensional strip. It is infinitely thin, has a finite width, and an infinite length. The scattering pattern of the strip depends upon its width and material composition. Varying these two factors provides a means for controlling the radar cross-section (RCS) of the strip. The goal of this thesis is to synthesize resistive tapers for the strip that produce desired bistatic scattering and backscattering patterns.

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

NASA Astrophysics Data System (ADS)

Ebisawa, Ken; Naoki, Iso

2012-07-01

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

Effect of course length and corridor width on the 2-minute walk test performance in geriatric patients.

PubMed

Lindemann, Ulrich; Beck, Luisa; Becker, Clemens

2017-02-01

To evaluate the effect of course length and corridor width on 2-minute walk test results in older adults. Cross-sectional and experimental study with different test conditions. Geriatric rehabilitation clinic. A total of 21 patients (median age 81 years). Patients walked two minutes on a 20 m and 40 m course with a 2 m or 1 m corridor width and on a continuous course without any turning in a corridor of 2 m width, five walks in total. The distance traveled within the 2 minutes was recorded. Compared with the 20 m course length, median walking distances measured by the 2-minute walk test in a walk way 2 m broad were better on the continuous corridor without any turn (136.9 m vs. 129.3 m, p = 0.002) and on the 40 m course (131.8 m vs. 129.3 m, p = 0.003). Walking distance on a 20 m course length was longer in a corridor of 2 m width compared with the 1 m corridor width (129.3 m vs. 119.2 m, p = 0.005). The walking distance was not affected by corridor width on the 40 m course length. Performance of elderly patients on the 2-minute walk test is influenced by the width of the corridor and the length of the course used.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, Yue; Liu, Xin; Loeb, Abraham

We perform a systematic search for sub-parsec binary supermassive black holes (BHs) in normal broad-line quasars at z < 0.8, using multi-epoch Sloan Digital Sky Survey (SDSS) spectroscopy of the broad Hβ line. Our working model is that (1) one and only one of the two BHs in the binary is active; (2) the active BH dynamically dominates its own broad-line region (BLR) in the binary system, so that the mean velocity of the BLR reflects the mean velocity of its host BH; (3) the inactive companion BH is orbiting at a distance of a few R{sub BLR}, where R{submore » BLR} ∼ 0.01-0.1 pc is the BLR size. We search for the expected line-of-sight acceleration of the broad-line velocity from binary orbital motion by cross-correlating SDSS spectra from two epochs separated by up to several years in the quasar rest frame. Out of ∼700 pairs of spectra for which we have good measurements of the velocity shift between two epochs (1σ error ∼40 km s{sup –1}), we detect 28 systems with significant velocity shifts in broad Hβ, among which 7 are the best candidates for the hypothesized binaries, 4 are most likely due to broad-line variability in single BHs, and the rest are ambiguous. Continued spectroscopic observations of these candidates will easily strengthen or disprove these claims. We use the distribution of the observed accelerations (mostly non-detections) to place constraints on the abundance of such binary systems among the general quasar population. Excess variance in the velocity shift is inferred for observations separated by longer than 0.4 yr (quasar rest frame). Attributing all the excess to binary motion would imply that most of the quasars in this sample must be in binaries, that the inactive BH must be on average more massive than the active one, and that the binary separation is at most a few times the size of the BLR. However, if this excess variance is partly or largely due to long-term broad-line variability, the requirement of a large population of close binaries is much weakened or even disfavored for massive companions. Future time-domain spectroscopic surveys of normal quasars can provide vital prior information on the structure function of stochastic velocity shifts induced by broad-line variability in single BHs. Such surveys with improved spectral quality, increased time baseline, and more epochs can greatly improve the statistical constraints of this method on the general binary population in broad-line quasars, further shrink the allowed binary parameter space, and detect true sub-parsec binaries.« less

Study on profile measurement of extruding tire tread by laser

NASA Astrophysics Data System (ADS)

Wang, LiangCai; Zhang, Wanping; Zhu, Weihu

1996-10-01

This paper presents a new 2D measuring system-profile measurement of extruding tire tread by laser. It includes the thickness measurement of extruding tire tread by laser and the width measurement of extruding tire tread using Moire Fringe. The system has been applied to process line of extruding tire tread. Two measuring results have been obtained. One is a standard profile picture of extruding tire tread including seven measuring values. Another one is a series of thickness and width values. When the scanning speed < 100mm/sec and total width < 800mm. The measuring errors of width < +/- 0.5mm. While the thickness range is < 40mm. The measuring errors of thickness < +/- 0.1mm.

Dynamic modeling of GMA fillet welding using cross-correlation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hellinga, M.; Huissoon, J.; Kerr, H.

1996-12-31

The feasibility of employing the cross-correlation system identification technique as a dynamic modeling method for the GMAW process was examined. This approach has the advantages of modeling speed, the ability to operate in low signal to noise environments, the ease of digital implementation, and the lack of model order assumption, making it ideal in a welding application. The width of the weld pool was the parameter investigated as a function of torch travel speed. Both on-line and off-line width measurements were used to identify the impulse response. Experimental results are presented and comparisons made with both step and ramp response.

Correction Factor for Gaussian Deconvolution of Optically Thick Linewidths in Homogeneous Sources

NASA Technical Reports Server (NTRS)

Kastner, S. O.; Bhatia, A. K.

1999-01-01

Profiles of optically thick, non-Gaussian emission line profiles convoluted with Gaussian instrumental profiles are constructed, and are deconvoluted on the usual Gaussian basis to examine the departure from accuracy thereby caused in "measured" linewidths. It is found that "measured" linewidths underestimate the true linewidths of optically thick lines, by a factor which depends on the resolution factor r congruent to Doppler width/instrumental width and on the optical thickness tau(sub 0). An approximating expression is obtained for this factor, applicable in the range of at least 0 <= tau(sub 0) <= 10, which can provide estimates of the true linewidth and optical thickness.

IR luminescence of tellurium-doped silica-based optical fibre

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dianov, Evgenii M; Alyshev, S V; Shubin, Aleksei V

2012-03-31

Tellurium-doped germanosilicate fibre has been fabricated by the MCVD process. In contrast to Te-containing glasses studied earlier, it has a broad luminescence band (full width at half maximum of {approx}350 nm) centred at 1500 nm, with a lifetime of {approx}2 {mu}s. The luminescence of the fibre has been studied before and after gamma irradiation in a {sup 60}Co source to 309 and 992 kGy. The irradiation produced a luminescence band around 1100 nm, with a full width at half maximum of {approx}400 nm and lifetime of {approx}5 {mu}s. (letters)

Characterization of the frequency stability of an optical frequency standard at 1.39 µm based upon noise-immune cavity-enhanced optical heterodyne molecular spectroscopy.

PubMed

Dinesan, H; Fasci, E; D'Addio, A; Castrillo, A; Gianfrani, L

2015-01-26

Frequency fluctuations of an optical frequency standard at 1.39 µm have been measured by means of a highly-sensitive optical frequency discriminator based on the fringe-side transmission of a high finesse optical resonator. Built on a Zerodur spacer, the optical resonator exhibits a finesse of 5500 and a cavity-mode width of about 120 kHz. The optical frequency standard consists of an extended-cavity diode laser that is tightly stabilized against the center of a sub-Doppler H(2) (18)O line, this latter being detected by means of noise-immune cavity-enhanced optical heterodyne molecular spectroscopy. The emission linewidth has been carefully determined from the frequency-noise power spectral density by using a rather simple approximation, known as β-line approach, as well as the exact method based on the autocorrelation function of the laser light field. It turns out that the linewidth of the optical frequency standard amounts to about 7 kHz (full width at half maximum) for an observation time of 1 ms. Compared to the free-running laser, the measured width corresponds to a line narrowing by a factor of ~220.

What is Driving the H I Velocity Dispersion?

NASA Astrophysics Data System (ADS)

Tamburro, D.; Rix, H.-W.; Leroy, A. K.; Mac Low, M.-M.; Walter, F.; Kennicutt, R. C.; Brinks, E.; de Blok, W. J. G.

2009-05-01

We explore what dominant physical mechanism sets the kinetic energy contained in neutral, atomic (H I) gas. Both supernova (SN) explosions and magnetorotational instability (MRI) have been proposed to drive turbulence in gas disks and we compare the H I line widths predicted from turbulence driven by these mechanisms to direct observations in 11 disk galaxies. We use high-quality maps of the H I mass surface density and line width, obtained by The H I Nearby Galaxy Survey. We show that all sample galaxies exhibit a systematic radial decline in the H I line width, which appears to be a generic property of H I disks and also implies a radial decline in kinetic energy density of H I. At a galactocentric radius of r 25—often comparable to the extent of significant star formation—there is a characteristic value of the H I velocity dispersion of 10 ± 2 km s-1. Inside this radius, galaxies show H I line widths well above the thermal value (corresponding to ~8 km s-1) expected from a warm H I component, implying that turbulence drivers must be responsible for maintaining this line width. Therefore, we compare maps of H I kinetic energy to maps of the star formation rate (SFR)—a proxy for the SN rate—and to predictions for energy generated by MRI. We find a positive correlation between kinetic energy of H I and SFR; this correlation also holds at fixed Σ_{H I}, as expected if SNe were driving turbulence. For a given turbulence dissipation timescale, we can estimate the energy input required to maintain the observed kinetic energy. The SN rate implied by the observed recent SFR is sufficient to maintain the observed velocity dispersion, if the SN feedback efficiency is at least epsilonSN sime 0.1 × (107 yr/τ D ), assuming τ D sime 107 yr for the turbulence dissipation timescale. Beyond r 25, this efficiency would have to increase to unrealistic values, epsilon gsim 1, suggesting that mechanical energy input from young stellar populations does not supply most kinetic energy in outer disks. On the other hand, both thermal broadening and turbulence driven by MRI can plausibly produce the velocity dispersions and kinetic energies that we observe in this regime (gsimr 25).

Observation of Neutral Sodium Above Mercury During the Transit of November 8, 2006

NASA Technical Reports Server (NTRS)

Potter, A. E.; Killen, R. M.; Reardon, Kevin P.; Bida, T. A.

2013-01-01

We mapped the absorption of sunlight by sodium vapor in the exosphere of Mercury during the transit of Mercury on November 8, 2006, using the IBIS Interferometric BIdimensional Spectrometer at the Dunn Solar Telescope operated by the National Solar Observatory at Sunspot, New Mexico. The measurements were reduced to line-of-sight equivalent widths for absorption at the sodium D2 line around the shadow of Mercury. The sodium absorption fell off exponentially with altitude up to about 600 km. However there were regions around north and south polar-regions where relatively uniform sodium absorptions extended above 1000 km. We corrected the 0-600 km altitude profiles for seeing blur using the measured point spread function. Analysis of the corrected altitude distributions yielded surface densities, zenith column densities, temperatures and scale heights for sodium all around the planet. Sodium absorption on the dawn side equatorial terminator was less than on the dusk side, different from previous observations of the relative absorption levels. We also determined Earthward velocities for sodium atoms, and line widths for the absorptions. Earthward velocities resulting from radiation pressure on sodium averaged 0.8 km/s, smaller than a prediction of 1.5 km/s. Most line widths were in the range of 20 mA after correction for instrumental broadening, corresponding to temperatures in the range of 1000 K.

Hα line measurements from ten diffuse galactic sources using the DEFPOS facility

NASA Astrophysics Data System (ADS)

Sahan, M.; Oflaz, F. M.; Yegingil, I.; Tel, E.

2015-08-01

The hydrogen Balmer-α emission line spectrum of ten diffuse ionization sources in the Milk Way - NGC 40 (WC8), NGC 2022, NGC 6210, NGC 6618 (M17, Sh2-45), NGC 6720 (M57), NGC 6781, NGC 6888 (Sh2-105), NGC 6992 (Sh2-103), NGC 7635 (Sh2-162,) and IC 1848 (Sh2-199) - has been investigated using a dual etalon Fabry-Pérot optical spectrometer (DEFPOS) aatached to the 150 cm RTT150 telescope at TUBITAK National Observatory (TUG, Antalya, Turkey: 36° 51' N; 30° 20' E; elevation: 2547 m). All of our galactic Hα observations discussed in this paper were carried out during the nights of 2013 June 21-24 with exposure time of 3600 s. As main results the intensity, the full width at half maximum, and the radial velocity with respect to the LSR have been determined for each data set. The intensities, the radial velocities, and the line widths of the Hα emission line vary from 59.15 to 8923.44 R, -46.72 to +54.07 km s-1, and 31.4 to 48.01 km s-1, respectively. The radial velocities and the half-widths of the H II regions and planetary nebulae determined from our measurements are found to be consistent with values given in literature, especially with those in Schneider et al. (1983) and Fich et al. (1990).