Structure of the Balmer jump. The isolated hydrogen atom

Science.gov (United States)

Calvo, F.; Belluzzi, L.; Steiner, O.

2018-06-01

Context. The spectrum of the hydrogen atom was explained by Bohr more than one century ago. We revisit here some of the aspects of the underlying quantum structure, with a modern formalism, focusing on the limit of the Balmer series. Aims: We investigate the behaviour of the absorption coefficient of the isolated hydrogen atom in the neighbourhood of the Balmer limit. Methods: We analytically computed the total cross-section arising from bound-bound and bound-free transitions in the isolated hydrogen atom at the Balmer limit, and established a simplified semi-analytical model for the surroundings of that limit. We worked within the framework of the formalism of Landi Degl'Innocenti & Landolfi (2004, Astrophys. Space Sci. Lib., 307), which permits an almost straight-forward generalization of our results to other atoms and molecules, and which is perfectly suitable for including polarization phenomena in the problem. Results: We analytically show that there is no discontinuity at the Balmer limit, even though the concept of a "Balmer jump" is still meaningful. Furthermore, we give a possible definition of the location of the Balmer jump, and we check that this location is dependent on the broadening mechanisms. At the Balmer limit, we compute the cross-section in a fully analytical way. Conclusions: The Balmer jump is produced by a rapid drop of the total Balmer cross-section, yet this variation is smooth and continuous when both bound-bound and bound-free processes are taken into account, and its shape and location is dependent on the broadening mechanisms.

COLLISIONLESS SHOCKS IN A PARTIALLY IONIZED MEDIUM. II. BALMER EMISSION

Energy Technology Data Exchange (ETDEWEB)

Morlino, G.; Bandiera, R.; Blasi, P.; Amato, E. [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy)

2012-12-01

Strong shocks propagating into a partially ionized medium are often associated with optical Balmer lines. This emission is due to impact excitation of neutral hydrogen by hot protons and electrons in the shocked gas. The structure of such Balmer-dominated shocks has been computed in a previous paper, where the distribution function of neutral particles was derived from the appropriate Boltzmann equation including coupling with ions and electrons through charge exchange and ionization. This calculation showed how the presence of neutrals can significantly modify the shock structure through the formation of a neutral-induced precursor ahead of the shock. Here we follow up on our previous work and investigate the properties of the resulting Balmer emission, with the aim of using the observed radiation as a diagnostic tool for shock parameters. Our main focus is on supernova remnant shocks, and we find that, for typical parameters, the H{alpha} emission typically has a three-component spectral profile, where (1) a narrow component originates from upstream cold hydrogen atoms, (2) a broad component comes from hydrogen atoms that have undergone charge exchange with shocked protons downstream of the shock, and (3) an intermediate component is due to hydrogen atoms that have undergone charge exchange with warm protons in the neutral-induced precursor. The relative importance of these three components depends on the shock velocity, on the original degree of ionization, and on the electron-ion temperature equilibration level. The intermediate component, which is the main signature of the presence of a neutral-induced precursor, becomes negligible for shock velocities {approx}< 1500 km s{sup -1}. The width of the intermediate line reflects the temperature in the precursor, while the width of the narrow one is left unaltered by the precursor. In addition, we show that the profiles of both the intermediate and broad components generally depart from a thermal distribution, as a

HYDRO2GEN: Non-thermal hydrogen Balmer and Paschen emission in solar flares generated by electron beams

Science.gov (United States)

Druett, M. K.; Zharkova, V. V.

2018-03-01

Aim. Sharp rises of hard X-ray (HXR) emission accompanied by Hα line profiles with strong red-shifts up to 4 Å from the central wavelength, often observed at the onset of flares with the Specola Solare Ticinese Telescope (STT) and the Swedish Solar Telescope (SST), are not fully explained by existing radiative models. Moreover, observations of white light (WL) and Balmer continuum emission with the Interface Region Imaging Spectrograph (IRISH) reveal strong co-temporal enhancements and are often nearly co-spatial with HXR emission. These effects indicate a fast effective source of excitation and ionisation of hydrogen atoms in flaring atmospheres associated with HXR emission. In this paper, we investigate electron beams as the agents accounting for the observed hydrogen line and continuum emission. Methods: Flaring atmospheres are considered to be produced by a 1D hydrodynamic response to the injection of an electron beam defining their kinetic temperatures, densities, and macro velocities. We simulated a radiative response in these atmospheres using a fully non-local thermodynamic equilibrium (NLTE) approach for a 5-level plus continuum hydrogen atom model, considering its excitation and ionisation by spontaneous, external, and internal diffusive radiation and by inelastic collisions with thermal and beam electrons. Simultaneous steady-state and integral radiative transfer equations in all optically thick transitions (Lyman and Balmer series) were solved iteratively for all the transitions to define their source functions with the relative accuracy of 10-5. The solutions of the radiative transfer equations were found using the L2 approximation. Resulting intensities of hydrogen line and continuum emission were also calculated for Balmer and Paschen series. Results: We find that inelastic collisions with beam electrons strongly increase excitation and ionisation of hydrogen atoms from the chromosphere to photosphere. This leads to an increase in Lyman continuum

Cross sections for Balmer-α excitation in heavy particle collisions

International Nuclear Information System (INIS)

Bae, Y.K.

1982-01-01

Doppler shifted and unshifted Balmer-α radiation has been observed in the absolute sense for energetic H + , H 2 + and H 3 + ions incident on molecular hydrogen by the method of decay inside the target within the energy range of 20 keV to 150 keV. Most of the measurements were based on single-collision conditions, but a simple thick-target experiment has been tried for the case of dissociative excitation of the target molecules by H atoms. The Balmer-α radiation emitted by hydrogen and deuterium beams has been used as a diagnostic method of neutral beam parameters. One important neutral beam parameter is the species mix between H + , H 2 + and H 3 + ion currents produced by the ion source and accelerator. This species mix can be resolved by analysis of the Balmer-α radiation if the beam is observed along an off normal axis with sufficient spectral resolution to separate the Doppler shifted radiation components from each other. An impediment to this approach to measuring the ion species is that some of the required cross sections have not been measured. This is the motivation for the presented experimental work. A home made monochromator gave enough optical throughput and spectral resolution for separation of the Doppler shifted lines from the unshifted lines. By selectively varying the target pressure and the distance of travel into the target prior to the observation region, excitation cross sections for three different angular momentum states (3s, 3p and 3d) have been determined. Combinations of a linear polarizer and a half-wave plate were used for polarization measurement

Balmer line diagnostic of electron heating at collisionless shocks in supernova remnants

International Nuclear Information System (INIS)

Rakowski, C.

2008-01-01

The mechanism and extent of electron heating at collisionless shocks has recently been under intense investigation. H α Balmer line emission is excited immediately behind the shock front and provides the best diagnostic for the electron to proton temperature ratio at supernova remnant shocks. Two components of emission are produced, a narrow component from electron and proton impact excitation of cold neutrals, and a broad component produced through charge exchange between the cold neutrals and the shock heated protons. Thus the broad and narrow component fluxes reflect the competition between electron and proton impact ionization, electron and proton impact excitation and charge exchange. This diagnostic has led to the discovery of an approximate inverse square relationship between the electron to proton temperature ratio and the shock velocity. In turn, this implies a constant level of electron heating, independent of shock speed above ∼ 450 km/s. In this talk I will present the observational evidence to date. Time permitting, I will introduce how lower-hybrid waves in an extended cosmic ray precursor could explain such a relationship, and how this and other parameters in the H α profile might relate to properties of cosmic rays and magnetic field amplification ahead of the shock. (author)

The Redshifted Hydrogen Balmer and Metastable He 1 Absorption Line System in Mini-FeLoBAL Quasar SDSS J112526.12+002901.3: A Parsec-scale Accretion Inflow?

Science.gov (United States)

Shi, Xi-Heng; Jiang, Peng; Wang, Hui-Yuan; Zhang, Shao-Hua; Ji, Tuo; Liu, Wen-Juan; Zhou, Hong-Yan

2016-10-01

The accretion of the interstellar medium onto central super-massive black holes is widely accepted as the source of the gigantic energy released by the active galactic nuclei. However, few pieces of observational evidence have been confirmed directly demonstrating the existence of the inflows. The absorption line system in the spectra of quasar SDSS J112526.12+002901.3 presents an interesting example in which the rarely detected hydrogen Balmer and metastable He I absorption lines are found redshifted to the quasar's rest frame along with the low-ionization metal absorption lines Mg II, Fe II, etc. The repeated SDSS spectroscopic observations suggest a transverse velocity smaller than the radial velocity. The motion of the absorbing medium is thus dominated by infall. The He I* lines present a powerful probe to the strength of ionizing flux, while the Balmer lines imply a dense environment. With the help of photoionization simulations, we find that the absorbing medium is exposed to the radiation with ionization parameter U ≈ 10-1.8, and the density is n({{H}})≈ {10}9 {{cm}}-3. Thus the absorbing medium is located ˜4 pc away from the central engine. According to the similarity in the distance and physical conditions between the absorbing medium and the torus, we strongly propose the absorption line system as a candidate for the accretion inflow, which originates in the inner surface of the torus.

Molecular enhancement of Balmer emissions following foil-induced dissociation of fast H2+ and H3+ ions

International Nuclear Information System (INIS)

Kobayashi, H.; Oda, N.

1984-01-01

Relative emission yields of Balmer lines as functions of the dwell time (t/sub D/ = 0.97--54.1 fs) in thin carbon foils (2--68 μg/cm 2 ) have been measured with (0.2--0.8)-MeV/amu H + , H 2 + , and H 3 + incident on thin carbon foils. Large molecular effects for emission yields of Balmer lines have been observed for H 2 + and H 3 + , where the molecular effect for H 3 + is larger than that for H 2 + . The molecular effects for H 2 + and H 3 + depend on the principal quantum number (n = 3--6), but this n dependence disappears at the largest t/sub D/ ( = 54.1 fs). The molecular effects rapidly decrease with increasing t/sub D/ in the small-t/sub D/ ( or approx. =2 fs) region. The magnitudes of the molecular effects at the largest t/sub D/ ( = 54.1 fs) are in good agreement with those by Andresen et al. [Phys. Scr. 19, 335 (1979)]. Relative populations of n-state hydrogens in the large-t/sub D/ (> or approx. =2 fs) region have been derived from the relative yields of Balmer lines as functions of n and t/sub D/. The molecular enhancement for relative populations of n-state hydrogens for H 2 + depends on n and t/sub D/, and decreases with increasing t/sub D/ and increases with increasing n

Formation of broad Balmer wings in symbiotic stars

International Nuclear Information System (INIS)

Chang, Seok-Jun; Heo, Jeong-Eun; Hong, Chae-Lin; Lee, Hee-Won

2016-01-01

Symbiotic stars are binary systems composed of a hot white dwarf and a mass losing giant. In addition to many prominent emission lines symbiotic stars exhibit Raman scattered O VI features at 6825 and 7088 Å. Another notable feature present in the spectra of many symbiotics is the broad wings around Balmer lines. Astrophysical mechanisms that can produce broad wings include Thomson scattering by free electrons and Raman scattering of Ly,β and higher series by neutral hydrogen. In this poster presentation we produce broad wings around Hα and H,β adopting a Monte Carlo techinique in order to make a quantitative comparison of these two mechanisms. Thomson wings are characterized by the exponential cutoff given by the termal width whereas the Raman wings are dependent on the column density and continuum shape in the far UV region. A brief discussion is provided. (paper)

Cross Sections for Balmer-Alpha Excitation in Heavy Particle Collisions.

Science.gov (United States)

Bae, Young Kun

Doppler shifted and unshifted Balmer-alpha radiation has been observed in the absolute sense for energetic H('+), H(,2)('+) and H(,3)('+) ions incident on molecular hydrogen by the method of decay inside the target within the energy range of 20 keV to 150 keV. Most of the measurements were based on single-collision conditions, but a simple thick -target experiment has been tried for the case of dissociative excitation of the target molecules by H atoms. The Balmer-alpha radiation emitted by hydrogen and deuterium beams has been used as a diagnostic method of neutral beam parameters. One important neutral beam parameter is the species mix between H('+), H(,2)('+) and H(,3)('+) ion currents produced by the ion source and accelerator. This species mix can be resolved by analysis of the Balmer-alpha radiation if the beam is observed along an off normal axis with sufficient spectral resolution to separate the Doppler shifted radiation components from each other. An impediment to this approach to measuring the ion species is that some of the required cross sections have not been measured. This is the motivation for the presented experimental work. A home made monochromator gave enough optical throughput and spectral resolution for separation of the Doppler shifted lines from the unshifted lines. By selectively varying the target pressure and the distance of travel into the target prior to the observation region, excitation cross sections for three different angular momentum states (3s, 3p and 3d) have been determined. Combinations of a linear polarizer and a half-wave plate were used for polarization measurement. Separation of the individual Zeeman levels have been tried for the 3p state from the information obtained from the polarization. Theoretical estimates of the cascading corrections have been applied in the case of both thin and thick targets. The intensity development equations for thick targets also have been derived. Cross sections for 3s production show

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

Energy Technology Data Exchange (ETDEWEB)

Ghavamian, Parviz [Department of Physics, Astronomy and Geosciences, Towson University, Towson, MD 21252 (United States); Seitenzahl, Ivo R.; Dopita, M. A. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Vogt, Frédéric P. A. [European Southern Observatory, Av. Alonso de Córdova 3107, 763 0355 Vitacura, Santiago (Chile); Terry, Jason P. [Department of Physics and Astronomy, University of Georgia (United States); Williams, Brian J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Winkler, P. Frank, E-mail: pghavamian@towson.edu [Department of Physics, Middlebury College, Middlebury, VT 05753 (United States)

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 CSM 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.

Doppler spectroscopy of hydrogen Balmer lines in a hollow cathode glow discharge in ammonia and argon-ammonia mixture

International Nuclear Information System (INIS)

Sisovic, N. M.; Konjevic, N.

2008-01-01

The results of Doppler spectroscopy of hydrogen Balmer lines from a stainless steel (SS) and copper (Cu) hollow cathode (HC) glow discharge in ammonia and argon-ammonia mixture are reported. The experimental profiles in ammonia discharge are fitted well by superposing three Gaussian profiles. The half widths, in energy units, of narrow and medium Gaussians are in the ranges 0.3-0.4 eV and 3-4 eV, respectively, for both hollow cathodes what is expected on the basis of earlier electron beam→NH 3 experiments. The half widths of the largest Gaussian in ammonia are 46 and 55 eV for SS and Cu HC, respectively. In argon-ammonia discharge, three Gaussians are also required to fit experimental profiles. While half widths of narrow and medium Gaussians are similar to those in ammonia, the half widths of the largest Gaussians are 35 and 42 eV for SS and Cu HC, respectively. The half widths of the largest Gaussians in ammonia and in argon-ammonia mixture indicate the presence of excessive Doppler broadening.

TheoSSA - Model WD Spectra on Demand: The Impact of Ne, Na, Mg, and Iron-group Elements on the Balmer Lines

Science.gov (United States)

Reindl, N.; Rauch, T.

2015-06-01

The registered German Astrophysical Virtual Observatory (GAVO) service TheoSSA provides easy access to synthetic stellar spectra. This GAVO database contains already ten thousands of these, which were calculated with different chemical compositions of the elements H to Ni. In addition to the database, it is possible to calculate individual spectra for hot, compact stars based on the Tübingen NLTE Model-Atmosphere Package (TMAP) via the TMAW service. The TMAW models were, in the pilot phase, restricted to the elements H, He, C, N, and O. Now, TMAW is extended to additionally consider opacities from Ne, Na, and Mg. Soon, TMAW will also be able to include the opacities from the so-called iron-group elements (Ca - Ni). We describe the improvements and show the impact of Ne, Na, Mg, and iron-group elements on the Balmer lines.

LINE FORMATION IN SPECTRA OF X-RAY NOVAE

OpenAIRE

Suleimanov, V. F.; Shimansky, V. V.

2017-01-01

Results of X-ray Novae (XN) optical spectra computation are presented. The continuum and Balmer line are calculated. The model of XN as a self-irradiated accretion disk is used. Local (for given radius) disk atmospheres as model stellar atmospheres, heated due to external X-ray radiation are treated. Changes of spectra shape and equivalent widths of the Balmer lines depending from the luminosity and some others accretion disk parameters are investigated. The comparison of GRO JO422+32 observe...

The Fourth Workshop on Lineshape Code Comparison: Line Merging

Directory of Open Access Journals (Sweden)

Spiros Alexiou

2018-03-01

Full Text Available For a given set of plasma parameters, along a single series (Lyman, Balmer, etc. the lines with higher principal quantum number (n lines get progressively wider, closer to each other, and start merging for a certain critical n. In the present work, four different codes (with further options are used to calculate the entire Balmer series for moderate and high electron densities. Particular attention is paid to the relevant physics, such as the cutoff criteria, strong and penetrating electron collisions.

BROADENING OF BALMER LINES FOR HIGH QUANTUM NUMBER

Energy Technology Data Exchange (ETDEWEB)

Armstrong, B. H.

1963-10-15

It is shown that the impact theory breakdown at sufficiently large distances from the line center in effect lowers the principle quantum number at which electron broadening might otherwise be assumed to dominate. Since the impact theory breaks down and effectively the impact widths decrease progressively for the line components more distant from the center, the contributions of the components to the folding integral decrease rapidly except at their own positions. (R.E.U.)

Solar cycle variations of geocoronal balmer α emission

International Nuclear Information System (INIS)

Nossal, S.; Reynolds, R.J.; Roesler, F.L.; Scherb, F.

1993-01-01

Observations of the geocoronal Balmer in nightglow have been made from Wisconsin for more than a solar cycle with an internally consistent intensity reference to standard astronomical nebulae. These measurements were made with a double etalon, pressure-scanned, 15-cm aperture Fabry-Perot interferometer. The resulting long time data provides an opportunity to examine solar cycle influence on the mid-latitude exosphere and to address accompanying questions concerning the degree to which the exosphere is locally static or changing. The exospheric Balmer α absolute intensity measurements reported here show no statistically significant variations throughout the solar cycle when the variation with viewing geometry is removed by normalizing the data to reference exospheric model predictions by Anderson et al. However, the relative intensity dependence on solar depression angle does show a solar cycle variation. This variation suggests a possible related variation in the exospheric hydrogen density profile, although other interpretations are also possible. The results suggest that additional well-calibrated data taken over a longer time span could probe low-amplitude variations over the solar cycle and test predictions of a slow monotonic increase in exospheric hydrogen arising from greenhouse gases. 21 refs., 9 figs., 2 tabs

Study of neutral hydrogen transport in LHD core plasmas based on high dynamic-range Balmer-α spectroscopy

International Nuclear Information System (INIS)

Fujii, K.; Goto, M.; Morita, S.

2014-10-01

The radial distributions of the neutral hydrogen atom density and pressure in the Large Helical Device (LHD) were studied. The atom density distribution was determined from a detailed analysis of the intensity-calibrated Balmer-α line profile while the pressure distribution was obtained with a simple one-dimensional analytical model. We determined for the first time the atom density at the center of a fusion-oriented plasma, which is approximately three orders smaller than that at the edge. On the contrary, the atom pressure changes only a factor of 10 from the edge to core regions. (author)

Hydrogen Balmer series measurements and determination of Rydberg's constant using two different spectrometers

International Nuclear Information System (INIS)

Amrani, D

2014-01-01

This paper investigates the use of two different methods, the optical and the computer-aided diffraction-grating spectrometer, to measure the wavelength of visible lines of Balmer series from the hydrogen atomic spectrum and estimate the value of Rydberg's constant. Analysis and interpretation of data showed that both methods, despite their difference in terms of the type of equipment used, displayed good performance in terms of precision of measurements of wavelengths of spectral lines. A comparison was carried out between the experimental value of Rydberg's constant obtained with both methods and the accepted value. The results of Rydberg's constant obtained with both the optical and computer-aided spectrometers were 1.099 28 × 10 −7  m −1  and 1.095 13 × 10 −7  m −1  with an error difference of 0.17% and 0.20% compared to the accepted value 1.097 373 × 10 −7  m −1 , respectively. (paper)

Reddening and He i{sup ∗} λ 10830 Absorption Lines in Three Narrow-line Seyfert 1 Galaxies

Energy Technology Data Exchange (ETDEWEB)

Zhang, Shaohua; Zhou, Hongyan; Shi, Xiheng; Pan, Xiang; Ji, Tuo; Jiang, Peng; Wang, Shufen [Polar Research Institute of China, 451 Jinqiao Road, Shanghai, 200136 (China); Liu, Wenjuan [Key Laboratory for the Structure and Evolution of Celestial Objects, Yunnan Observatories, Chinese Academy of Sciences, Kunming, Yunnan 650011 (China); Jiang, Ning, E-mail: zhangshaohua@pric.org.cn, E-mail: zhouhongyan@pric.org.cn [Key Laboratory for Researches in Galaxies and Cosmology, Department of Astronomy, University of Sciences and Technology of China, Chinese Academy of Sciences, Hefei, Anhui, 230026 (China)

2017-08-20

We report the detection of heavy reddening and the He i* λ 10830 absorption lines at the active galactic nucleus (AGN) redshift in three narrow-line Seyfert 1 galaxies: SDSS J091848.61+211717.0, SDSS J111354.66+124439.0, and SDSS J122749.13+321458.9. They exhibit very red optical to near-infrared colors, narrow Balmer/Paschen broad emission lines and He i* λ 10830 absorption lines. The ultraviolet-optical-infrared nucleus continua are reddened by the SMC extinction law of E ( B − V ) ∼ 0.74, 1.17, and 1.24 mag for three objects, which are highly consistent with the values obtained from the broad-line Balmer decrements, but larger than those of narrow emission lines. The reddening analysis suggests that the extinction dust simultaneously obscures the accretion disk, the broad emission-line region, and the hot dust from the inner edge of the torus. It is possible that the dust obscuring the AGN structures is the dusty torus itself. Furthermore, the Cloudy analysis of the He i* λ 10830 absorption lines proposes the distance of the absorption materials to be the extend scale of the torus, which greatly increases probabilities of the obscure and absorption materials being the dusty torus.

DISCOVERY OF A NOVA-LIKE CATACLYSMIC VARIABLE IN THE KEPLER MISSION FIELD

International Nuclear Information System (INIS)

Williams, Kurtis A.; De Martino, Domitilla; Silvotti, Roberto; Bruni, Ivan; Dufour, Patrick; Riecken, Thomas S.; Kronberg, Martin; Mukadam, Anjum; Handler, G.

2010-01-01

We announce the identification of a new cataclysmic variable (CV) star in the field of the Kepler Mission, KIC J192410.81+445934.9. This system was identified during a search for compact pulsators in the Kepler field. High-speed photometry reveals coherent large-amplitude variability with a period of 2.94 hr. Rapid, large-amplitude quasi-periodic variations are also detected on time scales of ∼1200 s and ∼650 s. Time-resolved spectroscopy covering one half photometric period shows shallow, broad Balmer and He I absorption lines with bright emission cores as well as strong He II and Bowen blend emission. Radial velocity variations are also observed in the Balmer and He I emission lines that are consistent with the photometric period. We therefore conclude that KIC J192410.81+445934.9 is a nova-like (NL) variable of the UX UMa class in or near the period gap, and it may belong to the rapidly growing subclass of SW Sex systems. Based on Two Micron All Sky Survey photometry and companion star models, we place a lower limit on the distance to the system of ∼500 pc. Due to limitations of our discovery data, additional observations including spectroscopy and polarimetry are needed to confirm the nature of this object. Such data will enable further understanding of the behavior of NL variables in the critical period range of 3-4 hr, where standard CV evolutionary theory finds major problems. The presence of this system in the Kepler Mission field of view also presents a unique opportunity to obtain a continuous photometric data stream of unparalleled length and precision on a CV system.

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

Science.gov (United States)

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 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.

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

Energy Technology Data Exchange (ETDEWEB)

Rakshit, Suvendu; Stalin, C. S., E-mail: suvenduat@gmail.com [Indian Institute of Astrophysics, Block II, Koramangala, Bangalore-560034 (India)

2017-06-20

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 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.

Ultraviolet photometry from the orbiting astronomical observatory. XVI - The stellar Lyman-alpha absorption line

Science.gov (United States)

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.

Nebular dust and extinction in ionized nebulae i.. the Balmer decrement

International Nuclear Information System (INIS)

Mathis, J.S.

1983-01-01

Many astronomical objects contain plasma with internal or surrounding dust. The extinction of H II regions can be determined from the H#betta#/Hα flux ratio, and also from the H#betta#/radio fluxes. The two determinations almost always disagree by large factors (typically, approx.3), with the (H#betta#/Hα) extinction being smaller. This is shown to be a consequence of the albedo of dust at Hα being smaller than that of H#betta#, so that the destruction of Hα by dust is larger than for constant albedo. If the difference in albedo is ignored, one interprets the lower Hα flux as being caused by a small optical depth in dust. Simple models for the geometry of the dust and emitting gas are discussed: spherical models with dust mixed with the ionized gas, and also a slab of absorbing dust overlying the nebula. The two geometries give similar results for the Balmer decrements, so geometry does not strongly enter the final results. The conclusion that albedo (Hα) 8000 A). Recommendations for dereddening emission-line objects are presented and should be applicable to planetary nebulae, active galactic nuclei, or quasi-stellar objects as well as to H II regions

THE LICK AGN MONITORING PROJECT: REVERBERATION MAPPING OF OPTICAL HYDROGEN AND HELIUM RECOMBINATION LINES

International Nuclear Information System (INIS)

Bentz, Misty C.; Walsh, Jonelle L.; Barth, Aaron J.; Thornton, Carol E.; Yoshii, Yuzuru; Sakata, Yu; Minezaki, Takeo; Woo, Jong-Hak; Malkan, Matthew A.; Wang, Xiaofeng; Steele, Thea N.; Silverman, Jeffrey M.; Serduke, Frank J. D.; Li, Weidong; Lee, Nicholas; Treu, Tommaso; Street, Rachel A.; Hidas, Marton G.; Hiner, Kyle D.; Greene, Jenny E.

2010-01-01

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 6 -10 7 M sun and also the well-studied nearby active galactic nucleus (AGN) NGC 5548. Nine of the objects in the sample (including NGC 5548) showed optical variability of sufficient strength during the monitoring campaign to allow for a time lag to be measured between the continuum fluctuations and the response to these fluctuations in the broad Hβ emission, which we have previously reported. We present here the light curves for the Hα, Hγ, He II λ4686, and He I λ5876 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 τ(Hα):τ(Hβ):τ(Hγ):τ(He I):τ(He II) = 1

A measurement of deuterium neutral by the Balmer-series in the STP-2 high beta screw pinch tokamak

International Nuclear Information System (INIS)

Yamaguchi, S.; Hirano, K.

1980-06-01

The Balmer-alpha and beta are measured with a calibrated spectrograph in STP-2 screw pinch tokamak operated under the maximum toroidal field being 9.2 kG, peak plasma current 30 kA and filling pressure 5 mtorr. The electron temperature and density profiles are obtained by ruby laser Thomson scattering. It is shown that electron temperature is about 10 eV and density is of the order of 10 14 /cm 3 . A non-cylindrical symmetric Abel-inversion technique is used to deduce the emission coefficient profiles from that of the line intensity of the Balmer's. In the present parameter range the neutral deuterium density is almost equal to the population density of the ground state, so that it is obtainable from measured intensities of D sub(α) and D sub(β) which give the population densities of the upper levels i = 3 and 4. The Collisional Radiative (CR) model is applied to the rate equations to estimate the ground state population density. It is found that at 4 μsec from the start of the discharge the deuterium neutral density may be approximately 2 x 10 12 /cm 3 at the center of plasma and 2 x 10 14 /cm 3 at the periphery. These values may contain an error of about factor two. Time history of neutral deuterium density is consistent with the increase of plasma density. (author)

Cataclysmic variables in the SUPERBLINK proper motion survey

Energy Technology Data Exchange (ETDEWEB)

Skinner, Julie N.; Thorstensen, John R. [Department of Physics and Astronomy, 6127 Wilder Laboratory, Dartmouth College, Hanover, NH 03755-3528 (United States); Lépine, Sébastien, E-mail: jns@dartmouth.edu [Department of Physics and Astronomy, Georgia State University, 25 Park Place NE, Atlanta, GA 30303 (United States)

2014-12-01

We have discovered a new high proper motion cataclysmic variable (CV) in the SUPERBLINK proper motion survey, which is sensitive to stars with proper motions greater than 40 mas yr{sup −1}. This CV was selected for follow-up observations as part of a larger search for CVs selected based on proper motions and their near-UV−V and V−K{sub s} colors. We present spectroscopic observations from the 2.4 m Hiltner Telescope at MDM Observatory. The new CV's orbital period is near 96 minutes, its spectrum shows the double-peaked Balmer emission lines characteristic of quiescent dwarf novae, and its V magnitude is near 18.2. Additionally, we present a full list of known CVs in the SUPERBLINK catalog.

Line Shape Variability in a Sample of AGN with Broad Lines

Indian Academy of Sciences (India)

2016-01-27

Jan 27, 2016 ... We give here a comparative review of the line shape variability in a sample of five type 1 AGNs, those with broad emission lines in their spectra, of the data obtained from the international long-term optical monitoring campaign coordinated by the Special Astrophysical Observatory of the Russian Academy ...

LABORATORY MEASUREMENTS OF WHITE DWARF PHOTOSPHERIC SPECTRAL LINES: Hβ

International Nuclear Information System (INIS)

Falcon, Ross E.; Gomez, T. A.; Montgomery, M. H.; Winget, D. E.; Rochau, G. A.; Bailey, J. E.; Nagayama, T.

2015-01-01

We spectroscopically measure multiple hydrogen Balmer line profiles from laboratory plasmas to investigate the theoretical line profiles used in white dwarf (WD) atmosphere models. X-ray radiation produced at the Z Pulsed Power Facility at Sandia National Laboratories initiates plasma formation in a hydrogen-filled gas cell, replicating WD photospheric conditions. Here we present time-resolved measurements of Hβ and fit this line using different theoretical line profiles to diagnose electron density, n e , and n = 2 level population, n 2 . Aided by synthetic tests, we characterize the validity of our diagnostic method for this experimental platform. During a single experiment, we infer a continuous range of electron densities increasing from n e ∼ 4 to ∼30 × 10 16 cm −3 throughout a 120-ns evolution of our plasma. Also, we observe n 2 to be initially elevated with respect to local thermodynamic equilibrium (LTE); it then equilibrates within ∼55 ns to become consistent with LTE. This supports our electron-temperature determination of T e ∼ 1.3 eV (∼15,000 K) after this time. At n e ≳ 10 17 cm −3 , we find that computer-simulation-based line-profile calculations provide better fits (lower reduced χ 2 ) than the line profiles currently used in the WD astronomy community. The inferred conditions, however, are in good quantitative agreement. This work establishes an experimental foundation for the future investigation of relative shapes and strengths between different hydrogen Balmer lines

Source of the violet depression in carbon stars (a study of the Balmer decrement in carbon L.P.V.s)

International Nuclear Information System (INIS)

Orlati, M.A.

1985-01-01

In an effort to determine the nature of the agent(s) of the violet depression in N-type stars through the behavior of their Balmer decrement, slit spectrograms of two C, one CS, two S (all reported to have the violet depression) and one M type LPVs were repeatedly taken between May 1983 and November 1984. The observed phase related changes in the Balmer decrement exclude the possibility that the absorbers are circumstellar because the emission region in the best-observed star is seen to rise through the opacity source. The exact nature and number of kinds of absorbers remains to be determined

New Observations of Balmer Continuum Flux in Solar Flares Instrument Description and First Results

Czech Academy of Sciences Publication Activity Database

Kotrč, Pavel; Procházka, O.; Heinzel, Petr

2016-01-01

Roč. 291, č. 3 (2016), s. 779-789 ISSN 0038-0938 R&D Projects: GA ČR GAP209/12/1652 Grant - others:EC(XE) 295272; EC(XE) 606862 Program:FP7; FP7 Institutional support: RVO:67985815 Keywords : flares * spectrum * Balmer continuum Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.682, year: 2016

An ultraviolet study of B[e] stars: evidence for pulsations, luminous blue variable type variations and processes in envelopes

Science.gov (United States)

Krtičková, I.; Krtička, J.

2018-06-01

Stars that exhibit a B[e] phenomenon comprise a very diverse group of objects in a different evolutionary status. These objects show common spectral characteristics, including the presence of Balmer lines in emission, forbidden lines and strong infrared excess due to dust. Observations of emission lines indicate illumination by an ultraviolet ionizing source, which is key to understanding the elusive nature of these objects. We study the ultraviolet variability of many B[e] stars to specify the geometry of the circumstellar environment and its variability. We analyse massive hot B[e] stars from our Galaxy and from the Magellanic Clouds. We study the ultraviolet broad-band variability derived from the flux-calibrated data. We determine variations of individual lines and the correlation with the total flux variability. We detected variability of the spectral energy distribution and of the line profiles. The variability has several sources of origin, including light absorption by the disc, pulsations, luminous blue variable type variations, and eclipses in the case of binaries. The stellar radiation of most of B[e] stars is heavily obscured by circumstellar material. This suggests that the circumstellar material is present not only in the disc but also above its plane. The flux and line variability is consistent with a two-component model of a circumstellar environment composed of a dense disc and an ionized envelope. Observations of B[e] supergiants show that many of these stars have nearly the same luminosity, about 1.9 × 105 L⊙, and similar effective temperatures.

FAR-ULTRAVIOLET SPECTROSCOPY OF THE NOVA-LIKE VARIABLE KQ MONOCEROTIS: A NEW SW SEXTANTIS STAR?

International Nuclear Information System (INIS)

Wolfe, Aaron; Sion, Edward M.; Bond, Howard E.

2013-01-01

New optical spectra obtained with the SMARTS 1.5 m telescope and archival International Ultraviolet Explorer (IUE) far-ultraviolet (FUV) spectra of the nova-like variable KQ Mon are discussed. The optical spectra reveal Balmer lines in absorption as well as He I absorption superposed on a blue continuum. The 2011 optical spectrum is similar to the KPNO 2.1 m IIDS spectrum we obtained 33 years earlier except that the Balmer and He I absorption is stronger in 2011. Far-ultraviolet IUE spectra reveal deep absorption lines due to C II, Si III, Si IV, C IV, and He II, but no P Cygni profiles indicative of wind outflow. We present the results of the first synthetic spectral analysis of the IUE archival spectra of KQ Mon with realistic optically thick, steady-state, viscous accretion-disk models with vertical structure and high-gravity photosphere models. We find that the photosphere of the white dwarf (WD) contributes very little FUV flux to the spectrum and is overwhelmed by the accretion light of a steady disk. Disk models corresponding to a WD mass of ∼0.6 M ☉ , with an accretion rate of order 10 –9 M ☉ yr –1 and disk inclinations between 60° and 75°, yield distances from the normalization in the range of 144-165 pc. KQ Mon is discussed with respect to other nova-like variables. Its spectroscopic similarity to the FUV spectra of three definite SW Sex stars suggests that it is likely a member of the SW Sex class and lends support to the possibility that the WD is magnetic.

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

Science.gov (United States)

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

2015-02-01

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

Non-LTE hydrogen-line formation in moving prominences

Science.gov (United States)

Heinzel, P.; Rompolt, B.

1986-01-01

The behavior of hydrogen-line brightness variations, depending on the prominence-velocity changes were investigated. By solving the NON-Local thermodynamic equilibrium (LTE) problem for hydrogen researchers determine quantitatively the effect of Doppler brightening and/or Doppler dimming (DBE, DDE) in the lines of Lyman and Balmer series. It is demonstrated that in low-density prominence plasmas, DBE in H alpha and H beta lines can reach a factor of three for velocities around 160 km/sec, while the L alpha line exhibits typical DDE. L beta brightness variations follow from a combined DBE in the H alpha and DDE in L alpha and L beta itself, providing that all relevant multilevel interlocking processes are taken into account.

An Anomaly in the Inglis-Teller Limits of the C VI Lyman and Balmer Series in Laser-Produced Plasmas

Science.gov (United States)

Elton, R.; Iglesias, E.; Griem, H.; Weaver, J.; Pien, G.; Mancini, R.

2002-11-01

Soft x-ray spectra from thin carbon layers heated by the OMEGA and NIKE lasers have been obtained with both spherical and planar targets, respectively, using a flat-field grazing incidence spectrograph equipped with a gated microchannel plate for temporal resolution. In both experiments, late-time (recombining) hydrogenic C VI spectra show an n-to-1 Lyman spectral series blending with the continuum at n=4, contrary to n=9 in the n-to-2 Balmer series. It appears unlikely that plasma inhomogeneities are the sole cause of this anomaly, given the difference in the experimental configurations. Other explanations for the line-to-continuum merging (other than the usual Stark-broadened Inglis-Teller effect) under consideration include non-thermal Doppler broadening, deviations from statistical sublevel population distributions, and opacity effects. Collisional-radiative and hydrodynamic modeling, including cascades, is employed to further understand this phenomenon.

Broad absorption line symbiotic stars: highly ionized species in the fast outflow from MWC 560

Science.gov (United States)

Lucy, Adrian B.; Knigge, Christian; Sokoloski, J. L.

2018-04-01

In symbiotic binaries, jets and disk winds may be integral to the physics of accretion onto white dwarfs from cool giants. The persistent outflow from symbiotic star MWC 560 (≡V694 Mon) is known to manifest as broad absorption lines (BALs), most prominently at the Balmer transitions. We report the detection of high-ionization BALs from C IV, Si IV, N V, and He II in International Ultraviolet Explorer spectra obtained on 1990 April 29 - 30, when an optical outburst temporarily erased the obscuring `iron curtain' of absorption troughs from Fe II and similar ions. The C IV and Si IV BALs reached maximum radial velocities at least 1000 km s-1 higher than contemporaneous Mg II and He II BALs; the same behaviors occur in the winds of quasars and cataclysmic variables. An iron curtain lifts to unveil high-ionization BALs during the P Cygni phase observed in some novae, suggesting by analogy a temporary switch in MWC 560 from persistent outflow to discrete mass ejection. At least three more symbiotic stars exhibit broad absorption with blue edges faster than 1500 km s-1; high-ionization BALs have been reported in AS 304 (≡V4018 Sgr), while transient Balmer BALs have been reported in Z And and CH Cyg. These BAL-producing fast outflows can have wider opening angles than has been previously supposed. BAL symbiotics are short-timescale laboratories for their giga-scale analogs, broad absorption line quasars (BALQSOs), which display a similarly wide range of ionization states in their winds.

A current controlled variable delay superconducting transmission line

International Nuclear Information System (INIS)

Anlage, S.M.; Snortland, H.J.; Beasley, M.R.

1989-01-01

The authors present a device concept for a current-controlled variable delay for superconducting transmission line. The device makes use of the change in kinetic inductance of a superconducting transmission line under the application of a DC bias current. The relevant materials parameters and several promising superconducting materials have been identified

Cataclysmic variables, Hubble-Sandage variables and eta Carinae

International Nuclear Information System (INIS)

Bath, G.T.

1980-01-01

The Hubble-Sandage variables are the most luminous stars in external galaxies. They were first investigated by Hubble and Sandage (1953) for use as distance indicators. Their main characteristics are high luminosity, blue colour indices, and irregular variability. Spectroscopically they show hydrogen and helium in emission with occasionally weaker FeII and [FeII], and no Balmer jump (Humphreys 1975, 1978). In this respect they closely resemble cataclysmic variables, particularly dwarf novae. In the quiescent state dwarf novae show broad H and HeI, together with a strong UV continuum. In contrast to the spectroscopic similarities, the luminosities could hardly differ more. Rather than being the brightest stars known, quiescent dwarf novae are as faint or fainter than the sun. It is suggested that the close correspondence between the spectral appearance of the two classes combined with the difference in luminosity is well accounted for by a model of Hubble-Sandage variables in which the same physical processes are occurring, but on a larger scale. (Auth.)

Development of Flexible Software Process Lines with Variability Operations

DEFF Research Database (Denmark)

Schramm, Joachim; Dohrmann, Patrick; Kuhrmann, Marco

2015-01-01

families of processes and, as part of this, variability operations provide means to modify and reuse pre-defined process assets. Objective: Our goal is to evaluate the feasibility of variability operations to support the development of flexible software process lines. Method: We conducted a longitudinal......Context: Software processes evolve over time and several approaches were proposed to support the required flexibility. Yet, little is known whether these approaches sufficiently support the development of large software processes. A software process line helps to systematically develop and manage...

Quasar outflow energetics from broad absorption line variability

Science.gov (United States)

McGraw, S. M.; Shields, J. C.; Hamann, F. W.; Capellupo, D. M.; Herbst, H.

2018-03-01

Quasar outflows have long been recognized as potential contributors to the co-evolution between supermassive black holes (SMBHs) and their host galaxies. The role of outflows in active galactic nucleus (AGN) feedback processes can be better understood by placing observational constraints on wind locations and kinetic energies. We utilize broad absorption line (BAL) variability to investigate the properties of a sample of 71 BAL quasars with P V broad absorption. The presence of P V BALs indicates that other BALs like C IV are saturated, such that variability in those lines favours clouds crossing the line of sight. We use these constraints with measurements of BAL variability to estimate outflow locations and energetics. Our data set consists of multiple-epoch spectra from the Sloan Digital Sky Survey and MDM Observatory. We detect significant (4σ) BAL variations from 10 quasars in our sample over rest-frame time-scales between ≤0.2-3.8 yr. Our derived distances for the 10 variable outflows are nominally ≲ 1-10 pc from the SMBH using the transverse-motion scenario, and ≲ 100-1000 pc from the central source using ionization-change considerations. These distances, in combination with the estimated high outflow column densities (i.e. NH ≳ 1022 cm-2), yield outflow kinetic luminosities between ˜ 0.001 and 1 times the bolometric luminosity of the quasar, indicating that many absorber energies within our sample are viable for AGN feedback.

Hydrogenic fast-ion diagnostic using Balmer-alpha light

International Nuclear Information System (INIS)

Heidbrink, W W; Burrell, K H; Luo, Y; Pablant, N A; Ruskov, E

2004-01-01

Hydrogenic fast-ion populations are common in toroidal magnetic fusion devices, especially in devices with neutral beam injection. As the fast ions orbit around the device and pass through a neutral beam, some fast ions neutralize and emit Balmer-alpha light. The intensity of this emission is weak compared with the signals from the injected neutrals, the warm (halo) neutrals and the cold edge neutrals, but, for a favourable viewing geometry, the emission is Doppler shifted away from these bright interfering signals. Signals from fast ions are detected in the DIII-D tokamak. When the electron density exceeds ∼7 x 10 19 m -3 , visible bremsstrahlung obscures the fast-ion signal. The intrinsic spatial resolution of the diagnostic is ∼5 cm for 40 keV amu -1 fast ions. The technique is well suited for diagnosis of fast-ion populations in devices with fast-ion energies (∼30 keV amu -1 ), minor radii (∼0.6 m) and plasma densities (∼ 20 m -3 ) that are similar to those of DIII-D

Development of Flexible Software Process Lines with Variability Operations

DEFF Research Database (Denmark)

Dohrmann, Patrick; Schramm, Joachim; Kuhrmann, Marco

2016-01-01

the development of flexible software process lines. Method: We conducted a longitudinal study in which we studied 5 variants of the V-Modell XT process line for 2 years. Results: Our results show the variability operation instrument feasible in practice. We analyzed 616 operation exemplars addressing various...

Extreme Variability in a Broad Absorption Line Quasar

Energy Technology Data Exchange (ETDEWEB)

Stern, Daniel; Jun, Hyunsung D. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Mail Stop 169-221, Pasadena, CA 91109 (United States); Graham, Matthew J.; Djorgovski, S. G.; Donalek, Ciro; Drake, Andrew J.; Mahabal, Ashish A.; Steidel, Charles C. [California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Arav, Nahum; Chamberlain, Carter [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Barth, Aaron J. [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697 (United States); Glikman, Eilat, E-mail: daniel.k.stern@jpl.nasa.gov [Department of Physics, Middlebury College, Middlebury, VT 05753 (United States)

2017-04-20

CRTS J084133.15+200525.8 is an optically bright quasar at z = 2.345 that has shown extreme spectral variability over the past decade. Photometrically, the source had a visual magnitude of V ∼ 17.3 between 2002 and 2008. Then, over the following five years, the source slowly brightened by approximately one magnitude, to V ∼ 16.2. Only ∼1 in 10,000 quasars show such extreme variability, as quantified by the extreme parameters derived for this quasar assuming a damped random walk model. A combination of archival and newly acquired spectra reveal the source to be an iron low-ionization broad absorption line quasar with extreme changes in its absorption spectrum. Some absorption features completely disappear over the 9 years of optical spectra, while other features remain essentially unchanged. We report the first definitive redshift for this source, based on the detection of broad H α in a Keck/MOSFIRE spectrum. Absorption systems separated by several 1000 km s{sup −1} in velocity show coordinated weakening in the depths of their troughs as the continuum flux increases. We interpret the broad absorption line variability to be due to changes in photoionization, rather than due to motion of material along our line of sight. This source highlights one sort of rare transition object that astronomy will now be finding through dedicated time-domain surveys.

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

International Nuclear Information System (INIS)

Grier, C. J.; Peterson, B. M.; Pogge, R. W.; De Rosa, G.; Martini, Paul; Kochanek, C. S.; Zu, Y.; Shappee, B.; Beatty, T. G.; Salvo, C. Araya; Bird, J. C.; Horne, Keith; Bentz, M. C.; Denney, K. D.; Siverd, R.; Sergeev, S. G.; Borman, G. A.; Kaspi, S.; Bord, D. J.; Che, X.

2013-01-01

We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum entropy method for four objects: Mrk 335, Mrk 1501, 3C 120, and PG 2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different velocity bins of the Hβ emission line. The four velocity-delay maps show unique dynamical signatures for each object. For 3C 120, the Balmer lines show kinematic signatures consistent with both an inclined disk and infalling gas, but the He II λ4686 emission line is suggestive only of inflow. The Balmer lines in Mrk 335, Mrk 1501, and PG 2130+099 show signs of infalling gas, but the He II emission in Mrk 335 is consistent with an inclined disk. We also see tentative evidence of combined virial motion and infalling gas from the velocity-binned analysis of Mrk 6. The maps for 3C 120 and Mrk 335 are two of the most clearly defined velocity-delay maps to date. These maps constitute a large increase in the number of objects for which we have resolved velocity-delay maps and provide evidence supporting the reliability of reverberation-based black hole mass measurements.

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

Energy Technology Data Exchange (ETDEWEB)

Grier, C. J.; Peterson, B. M.; Pogge, R. W.; De Rosa, G.; Martini, Paul; Kochanek, C. S.; Zu, Y.; Shappee, B.; Beatty, T. G.; Salvo, C. Araya; Bird, J. C. [Department of Astronomy, The Ohio State University, 140 W 18th Ave, Columbus, OH 43210 (United States); Horne, Keith [SUPA Physics and Astronomy, University of St. Andrews, Fife, KY16 9SS Scotland (United Kingdom); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, One Park Place South SE, Suite 700, Atlanta, GA 30303 (United States); Denney, K. D. [Marie Curie Fellow at the Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Siverd, R. [Department of Physics and Astronomy, Vanderbilt University, 5301 Stevenson Center, Nashville, TN 37235 (United States); Sergeev, S. G.; Borman, G. A. [Crimean Astrophysical Observatory, P/O Nauchny Crimea 98409 (Ukraine); Kaspi, S. [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Bord, D. J. [Department of Natural Sciences, The University of Michigan - Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128 (United States); Che, X. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 41809 (United States); and others

2013-02-10

We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum entropy method for four objects: Mrk 335, Mrk 1501, 3C 120, and PG 2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different velocity bins of the H{beta} emission line. The four velocity-delay maps show unique dynamical signatures for each object. For 3C 120, the Balmer lines show kinematic signatures consistent with both an inclined disk and infalling gas, but the He II {lambda}4686 emission line is suggestive only of inflow. The Balmer lines in Mrk 335, Mrk 1501, and PG 2130+099 show signs of infalling gas, but the He II emission in Mrk 335 is consistent with an inclined disk. We also see tentative evidence of combined virial motion and infalling gas from the velocity-binned analysis of Mrk 6. The maps for 3C 120 and Mrk 335 are two of the most clearly defined velocity-delay maps to date. These maps constitute a large increase in the number of objects for which we have resolved velocity-delay maps and provide evidence supporting the reliability of reverberation-based black hole mass measurements.

Spectral Variability of the UXOR Star RR Tau Over 2.5 Magnitudes in V

Science.gov (United States)

Rodgers, B.; Wooden, D. H.; Grinin, V. P.; Shakhovskoy, D.

2000-12-01

We present moderate resolution optical spectra of the highly variable Herbig Ae star RR Tau over 12 epochs spanning 2.5 magnitudes in V. The data cover most of the optical spectrum from the CaII K line in the blue to the CaII infrared triplet in the far red. Using contemporaneous photometric measurements from two sources, we have reliable estimates of the visual magnitude of the system at each spectral epoch. We find some spectral activity to be closely correlated with photometric variability, while other features are remarkably stable. Significant variability is common in the cores of Hα and Hβ , but is not well correlated with photometric variability. On the other hand, the wings (Δ v>400km/s) of the Balmer lines are quite stable, showing no change in spectral type when compared to Kurucz line profiles. This, along with the constant equivalent width seen in several weak metal lines, suggest that the physical conditions of the underlying continuum source are not changing significantly, despite a factor of ten change in brightness. In contrast, strong low-ionization permitted lines, such as FeII, CaII and NaI, are seen in deep absorption when the star is bright (V <= 12), but disappear during photometric minima to reveal weak emission lines. These absorption lines are not being filled in by the emission but rather are physically disappearing from the system. This could occur, for example, if an obscuring screen moved between the continuum source and the absorbing gas. The [OI]6300 line, a common wind diagnostic, is seen in emission at all epochs, with flux which is roughly constant except increasing slightly when the system is faint. We discuss these data in the context of different scenarios for the photometric variability and find them to be more consistent with the obscuration hypothesis, than changing accretion luminosity. This work is part of the dissertation research of B. Rodgers, which has been funded in large part by a NASA Graduate Student Research

OPTICAL MONITORING OF THE BROAD-LINE RADIO GALAXY 3C 390.3

International Nuclear Information System (INIS)

Dietrich, Matthias; Peterson, Bradley M.; Grier, Catherine J.; Bentz, Misty C.; Eastman, Jason; Frank, Stephan; Gonzalez, Raymond; Marshall, Jennifer L.; DePoy, Darren L.; Prieto, Jose L.

2012-01-01

We have undertaken a new ground-based monitoring campaign on the broad-line radio galaxy 3C 390.3 to improve the measurement of the size of the broad emission-line region and to estimate the black hole mass. Optical spectra and g-band images were observed in late 2005 for three months using the 2.4 m telescope at MDM Observatory. Integrated emission-line flux variations were measured for the hydrogen Balmer lines Hα, Hβ, Hγ, and for the helium line He IIλ4686, as well as g-band fluxes and the optical active galactic nucleus (AGN) continuum at λ = 5100 Å. The g-band fluxes and the optical AGN continuum vary simultaneously within the uncertainties, τ cent (0.2 ± 1.1) days. We find that the emission-line variations are delayed with respect to the variable g-band continuum by τ(Hα) 56.3 +2.4 –6.6 days, τ(Hβ) = 44.3 +3.0 –3.3 days, τ(Hγ) = 58.1 +4.3 –6.1 days, and τ(He II 4686) = 22.3 +6.5 –3.8 days. The blue and red peaks in the double-peaked line profiles, as well as the blue and red outer profile wings, vary simultaneously within ±3 days. This provides strong support for gravitationally bound orbital motion of the dominant part of the line-emitting gas. Combining the time delay of the strong Balmer emission lines of Hα and Hβ and the separation of the blue and red peaks in the broad double-peaked profiles in their rms spectra, we determine M vir bh = 1.77 +0.29 –0.31 × 10 8 M ☉ and using σ line of the rms spectra M vir bh 2.60 +0.23 –0.31 × 10 8 M ☉ for the central black hole of 3C 390.3, respectively. Using the inclination angle of the line-emitting region which is measured from superluminal motion detected in the radio range, accretion disk models to fit the optical double-peaked emission-line profiles, and X-ray observations, the mass of the black hole amounts to M bh = 0.86 +0.19 –0.18 × 10 9 M ☉ (peak separation) and M bh 1.26 +0.21 –0.16 × 10 9 M ☉ (σ line ), respectively. This result is consistent with the black

Simultaneous influence of Stark effect and excessive line broadening on the Hα line

Science.gov (United States)

Cvetanović, Nikola; Ivković, Saša S.; Obradović, Bratislav M.; Kuraica, Milorad M.

2017-12-01

The aim of this paper is to study the combined influence of the Stark effect and the excessive Doppler broadening on the Balmer alpha line in hydrogen discharges. Since this line is a good candidate for measuring electric field in various types of discharges with different gas compositions, a simple method for field measurement based on polarization spectroscopy is developed, that includes all the excitation mechanisms. To simultaneously test the flexibility of the fitting procedure and investigate the excessive broadening, we applied the fitting procedure on line profiles obtained at a range of conditions from two different discharges. The range of pressures and voltages was examined in an abnormal glow and in dielectric barrier discharge operating with hydrogen gas. The model fitting function was able to respond and follow the change in the line profile caused by the change of conditions. This procedure can therefore be recommended for electric field measurement. Contribution to the "Topical Issue: Physics of Ionized Gases (SPIG 2016)", edited by Goran Poparic, Bratislav Obradovic, Dragana Maric and Aleksandar Milosavljevic.

On the SW Sex-type eclipsing cataclysmic variable SDSS0756+0858

Energy Technology Data Exchange (ETDEWEB)

Tovmassian, Gagik; Hernandez, Mercedes Stephania; González-Buitrago, Diego; Zharikov, Sergey; García-Díaz, Maria Teresa, E-mail: gag@astro.unam.mx [Instituto de Astronomía, Universidad Nacional Autonoma de México, Apdo. Postal 877, Ensenada, Baja California 22800 (Mexico)

2014-03-01

We conducted a spectroscopic and photometric study of SDSS J075653.11+085831. X-ray observations were also attempted. We determined the orbital period of this binary system to be 3.29 hr. It is a deep eclipsing system, whose spectra show mostly single-peaked, Balmer emission lines and a rather intense He II line. There is also the presence of faint (often double-peaked) He I emission lines as well as several absorption lines, Mg I being the most prominent. All of these features point toward the affiliation of this object with the growing number of SW Sex-type objects. We developed a phenomenological model of an SW Sex system to reproduce the observed photometric and spectral features.

On the SW Sex-type eclipsing cataclysmic variable SDSS0756+0858

International Nuclear Information System (INIS)

Tovmassian, Gagik; Hernandez, Mercedes Stephania; González-Buitrago, Diego; Zharikov, Sergey; García-Díaz, Maria Teresa

2014-01-01

We conducted a spectroscopic and photometric study of SDSS J075653.11+085831. X-ray observations were also attempted. We determined the orbital period of this binary system to be 3.29 hr. It is a deep eclipsing system, whose spectra show mostly single-peaked, Balmer emission lines and a rather intense He II line. There is also the presence of faint (often double-peaked) He I emission lines as well as several absorption lines, Mg I being the most prominent. All of these features point toward the affiliation of this object with the growing number of SW Sex-type objects. We developed a phenomenological model of an SW Sex system to reproduce the observed photometric and spectral features.

Genetic variability among advanced lines of brassica

International Nuclear Information System (INIS)

Ullah, N.; Farhatullah, A.; Rahman, H.U.; Fayyaz, L.

2015-01-01

Genetic variability for morphological and biochemical traits among six advanced lines (F10:11) of brassica was studied at The University of Agriculture Peshawar during crop season of 2012-13. These lines were developed through interspecific hybridization. Significant differences at (p=0.01) for plant height, main, pods main raceme-1, pod length, seed yield plant-1 and protein content at (p=0.05) for 100-seed weight, oil content were recorded. The advanced line, AUP-05 produced the maximum seed yield plant-1 (19.73 g), protein content (24.56%), 100-seed weight (0.64 g). Advanced line AUP-04 had the highest erucic acid (50.31%), linolenic acid (10.60%) and was late maturing (179.33). Advanced line AUP-06 produced the high oil content (48.82%). Advanced line AUP-03 produced comparatively longer main raceme (69.32 cm). Environmental variance was smaller than genotypic variance for majority of the traits. Genotypic and phenotypic coefficients of variation ranged from 2.45 to 25.67% and 2.50 to 27.68%, respectively. Heritability was high for majority of the traits. The maximum heritability was recorded for plant height (0.61), main raceme length (0.81), pods main raceme-1 (0.74), seed yield plant-1 (0.86) and protein content (0.77). Moderate heritability was observed for oil (0.58) contents. Heritability for 100-seed weight (0.30) was the lowest. These lines may be released as new improved varieties for specific parameters. (author)

CCD observations of the spatial structure of the hydrogen Balmer-alpha (Hα) diffuse galactic background

International Nuclear Information System (INIS)

Brinkmann, J.V.

1987-01-01

Images of hydrogen Balmer alpha emission were obtained in the galactic plane at the Orion arm rest velocity at longitudes of 66, 96, and 114 0 and at the Perseus arm velocity at 114 0 . These directions were chosen because of their lack of birth nebular emission and their high [Sll]6731/Hα ratio, a characteristic of the faint galactic emission-line background. The narrow band (0.26A) images were obtained during June and August 1985, and June 1986, with a newly-constructed RCA SID501DX CCD camera used with the existing 15-cm Fabry-Perot spectrometer at the Physical Sciences Laboratory of the University of Wisconsin, Madison. The field of view was 0. 0 75, with each binned pixel covering about two arc minutes. All images show a significant variation in detected Hα emission at the third-of-half-degree scale. The emission intensity varies by a factor of two over each field of view. Comparison of Orion arm and Perseus arm results indicates extinction is the most-likely cause of the observed spatial structure but star counts taken from the blue plate of Palomar Sky Survey show little spatial correlation with the α emission. This dilemma may be resolved by further investigations using IRAS images, which were not available in time for inclusion in this thesis

Assessment of genetic variability of maize inbred lines and their ...

African Journals Online (AJOL)

Assessment of genetic variability of maize inbred lines and their hybrids under normal and drought conditions. ... Nigeria Agricultural Journal ... Analysis of variance revealed significant differences for most of the characters under study which indicates the presence of sufficient amount of variability offering ample scope for ...

Discovery of a new bona fide luminous blue variable in Norma

Science.gov (United States)

Gvaramadze, V. V.; Kniazev, A. Y.; Berdnikov, L. N.

2015-12-01

We report the results of optical spectroscopy of the candidate evolved massive star MN44 revealed via detection of a circular shell with the Spitzer Space Telescope. First spectra taken in 2009 May-June showed the Balmer lines in emission as well as numerous emission lines of iron, which is typical of luminous blue variables (LBVs) near the visual maximum. New observations carried out in 2015 May-September detected significant changes in the spectrum, indicating that the star became hotter. We found that these changes are accompanied by significant brightness variability of MN44. In particular, the Ic-band brightness decreased by ≈ 1.6 mag during the last six years and after reaching its minimum in 2015 June has started to increase. Using archival data, we also found that the Ic-band brightness increased by ≈3 mag in ≈30 yr preceding our observations. MN44 therefore represents the 17th known example of the Galactic bona fide LBVs. We detected a nitrogen-rich knot to the north-west of the star, which might represent an interstellar cloudlet interacting with the circumstellar shell. We discuss a possible association between MN44 and the INTEGRAL transient source of hard X-ray emission IGR J16327-4940, implying that MN44 might be either a colliding-wind binary or a high-mass X-ray binary.

Optical emission line spectra of Seyfert galaxies and radio galaxies

International Nuclear Information System (INIS)

Osterbrock, D.E.

1978-01-01

Many radio galaxies have strong emission lines in their optical spectra, similar to the emission lines in the spectra of Seyfert galaxies. The range of ionization extends from [O I] and [N I] through [Ne V] and [Fe VII] to [Fe X]. The emission-line spectra of radio galaxies divide into two types, narrow-line radio galaxies whose spectra are indistinguishable from Seyfert 2 galaxies, and broad-line radio galaxies whose spectra are similar to Seyfert 1 galaxies. However on the average the broad-line radio galaxies have steeper Balmer decrements, stronger [O III] and weaker Fe II emission than the Seyfert 1 galaxies, though at least one Seyfert 1 galaxy not known to be a radio source has a spectrum very similar to typical broad-line radio galaxies. Intermediate-type Seyfert galaxies exist that show various mixtures of the Seyfert 1 and Seyfert 2 properties, and the narrow-line or Seyfert 2 property seems to be strongly correlated with radio emission. (Auth.)

Spectral properties of X-ray selected narrow emission line galaxies

Science.gov (United States)

Romero-Colmenero, E.

1998-03-01

This thesis reports a study of the X-ray and optical properties of two samples of X-ray selected Narrow Emission Line Galaxies (NELGs), and their comparison with the properties of broad line Active Galactic Nuclei (AGN). One sample (18 NELGs) is drawn from the ROSAT International X-ray Optical Survey (RIXOS), the other (19 NELGs and 33 AGN) from the ROSAT UK Deep Survey. ROSAT multi-channel X-ray spectra have been extracted and fitted with power-law, bremsstrahlung and black body models for the brighter RIXOS sources. In most cases, power-law and bremsstrahlung models provide the best results. The average spectral energy index, alpha, of the RIXOS NELGs is 0.96 +/- 0.07, similar to that of AGN (alpha~1). For the fainter RIXOS NELGs, as well as for all the UK Deep Survey sources, counts in three spectral bands have been extracted and fitted with a power-law model, assuming the Galactic value for N_H. The brighter RIXOS sources demonstrated that the results obtained by these two different extraction and fitting procedures provide consistent results. Two average X-ray spectra, one for the NELGs and another for the AGN, were created from the UK Deep Survey sources. The power-law slope of the average NELG is alpha = 0.45 +/- 0.09, whilst that of the AGN is alpha = 0.96 +/- 0.03. ROSAT X-ray surveys have shown that the fractional surface density of NELGs increases with respect to AGN at faint fluxes (case for NELGs to be major contributors to the XRB at the fainter fluxes. The analysis of optical spectroscopy, obtained on La Palma and Hawaii, shows that NELGs form a very heterogeneous group, made up of a mixture of Seyfert 2, LINER and HII-region like galaxies. Seyfert 2 galaxies are found to possess in general the steepest X-ray slopes. Ways to explain this in the context of the unified model of AGN are discussed. The FWHM of some emission lines (Halpha, Hbeta, [NII]) in the NELGs appears to increase with steepening X-ray spectral slope. In the case of the Balmer lines

OPTICAL MONITORING OF THE BROAD-LINE RADIO GALAXY 3C 390.3

Energy Technology Data Exchange (ETDEWEB)

Dietrich, Matthias; Peterson, Bradley M.; Grier, Catherine J.; Bentz, Misty C.; Eastman, Jason; Frank, Stephan; Gonzalez, Raymond; Marshall, Jennifer L.; DePoy, Darren L.; Prieto, Jose L., E-mail: dietrich@astronomy.ohio-state.edu [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)

2012-09-20

We have undertaken a new ground-based monitoring campaign on the broad-line radio galaxy 3C 390.3 to improve the measurement of the size of the broad emission-line region and to estimate the black hole mass. Optical spectra and g-band images were observed in late 2005 for three months using the 2.4 m telescope at MDM Observatory. Integrated emission-line flux variations were measured for the hydrogen Balmer lines H{alpha}, H{beta}, H{gamma}, and for the helium line He II{lambda}4686, as well as g-band fluxes and the optical active galactic nucleus (AGN) continuum at {lambda} = 5100 A. The g-band fluxes and the optical AGN continuum vary simultaneously within the uncertainties, {tau}{sub cent} (0.2 {+-} 1.1) days. We find that the emission-line variations are delayed with respect to the variable g-band continuum by {tau}(H{alpha}) 56.3{sup +2.4}{sub -6.6} days, {tau}(H{beta}) = 44.3{sup +3.0}{sub -3.3} days, {tau}(H{gamma}) = 58.1{sup +4.3}{sub -6.1} days, and {tau}(He II 4686) = 22.3{sup +6.5}{sub -3.8} days. The blue and red peaks in the double-peaked line profiles, as well as the blue and red outer profile wings, vary simultaneously within {+-}3 days. This provides strong support for gravitationally bound orbital motion of the dominant part of the line-emitting gas. Combining the time delay of the strong Balmer emission lines of H{alpha} and H{beta} and the separation of the blue and red peaks in the broad double-peaked profiles in their rms spectra, we determine M {sup vir}{sub bh} = 1.77{sup +0.29}{sub -0.31} Multiplication-Sign 10{sup 8} M{sub Sun} and using {sigma}{sub line} of the rms spectra M {sup vir}{sub bh} 2.60{sup +0.23}{sub -0.31} Multiplication-Sign 10{sup 8} M{sub Sun} for the central black hole of 3C 390.3, respectively. Using the inclination angle of the line-emitting region which is measured from superluminal motion detected in the radio range, accretion disk models to fit the optical double-peaked emission-line profiles, and X-ray observations

H α and H β Raman scattering line profiles of the symbiotic star AG Pegasi

Science.gov (United States)

Lee, Seong-Jae; Hyung, Siek

2018-04-01

The H α and H β line profiles of the symbiotic star AG Pegasi, observed in 1998 September (phase ϕ = 10.24), display top narrow double Gaussian components and bottom broad components (FWHM = 200-400 km s-1). The photoionization model indicates that the ionized zone, responsible for the hydrogen Balmer and Lyman lines, is radiation-bounded, with a hydrogen gas number density of nH ˜ 109.85 cm-3 and a gas temperature of Te = 12 000-15 000 K. We have carried out Monte Carlo simulations to fit the Raman scattering broad wings, assuming that the hydrogen Ly β and Ly γ lines emitted within the radiation-bounded H II zone around a white dwarf have the same double Gaussian line profile shape as the hydrogen Balmer lines. The simulation shows that the scattering H I zones are attached to (or located just outside) the inner H II shells. The best fit to the observed broad H I line profiles indicates that the column density of the scattering neutral zone is NH ≃ 3-5 × 1019 cm-2. We have examined whether the geometrical structure responsible for the observed H α and H β line profiles is a bipolar conical shell structure, consisting of the radiation-bounded ionized zone and the outer material bounded neutral zone. The expanding bipolar structure might be two opposite regions of the common envelope or the outer shell of the Roche lobe around the hot white dwarf, formed through the mass inflows from the giant star and pushed out by the fast winds from the hot white dwarf.

Rapid grounding line migration induced by internal variability of a marine-terminating ice stream

Science.gov (United States)

Robel, A.; Schoof, C.; Tziperman, E.

2013-12-01

Numerous studies have found significant variability in the velocity of ice streams to be a prominent feature of geomorphologic records in the Siple Coast (Catania et al. 2012) and other regions in West Antarctica (Dowdeswell et al. 2008). Observations indicate that grounding line position is strongly influenced by ice stream variability, producing rapid grounding line migration in the recent past (Catania et al. 2006) and the modern (Joughin & Tulaczyk 2002). We analyze the interaction of grounding line mass flux and position in a marine-terminating ice stream using a stretch-coordinate flowline model. This model is based on that described in Schoof (2007), with a mesh refined near the grounding line to ensure accurate resolution of the mechanical transition zone. Here we have added lateral shear stress (Dupont & Alley 2005) and an undrained plastic bed (Tulaczyk et al. 2000). The parameter dependence of ice stream variability seen in this model compares favorably to both simpler (Robel et al. 2013) and more complex (van der Wel et al. 2013) models, though with some key differences. We find that thermally-induced internal ice stream variability can cause very rapid grounding line migration even in the absence of retrograde bed slopes or external forcing. Activation waves propagate along the ice stream length and trigger periods of rapid grounding line migration. We compare the behavior of the grounding line due to internal ice stream variability to changes triggered externally at the grounding line such as the rapid disintegration of buttressing ice shelves. Implications for Heinrich events and the Marine Ice Sheet Instability are discussed.

A new beam emission polarimetry diagnostic for measuring the magnetic field line angle at the plasma edge of ASDEX Upgrade.

Science.gov (United States)

Viezzer, E; Dux, R; Dunne, M G

2016-11-01

A new edge beam emission polarimetry diagnostic dedicated to the measurement of the magnetic field line angle has been installed on the ASDEX Upgrade tokamak. The new diagnostic relies on the motional Stark effect and is based on the simultaneous measurement of the polarization direction of the linearly polarized π (parallel to the electric field) and σ (perpendicular to the electric field) lines of the Balmer line D α . The technical properties of the system are described. The calibration procedures are discussed and first measurements are presented.

A RADIAL VELOCITY TEST FOR SUPERMASSIVE BLACK HOLE BINARIES AS AN EXPLANATION FOR BROAD, DOUBLE-PEAKED EMISSION LINES IN ACTIVE GALACTIC NUCLEI

Energy Technology Data Exchange (ETDEWEB)

Liu, Jia; Halpern, Jules P. [Astronomy Department, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Eracleous, Michael [Department of Astronomy and Institute for Gravitation and The Cosmos, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)

2016-01-20

One of the proposed explanations for the broad, double-peaked Balmer emission lines observed in the spectra of some active galactic nuclei (AGNs) is that they are associated with sub-parsec supermassive black hole (SMBH) binaries. Here, we test the binary broad-line region hypothesis through several decades of monitoring of the velocity structure of double-peaked Hα emission lines in 13 low-redshift, mostly radio-loud AGNs. This is a much larger set of objects compared to an earlier test by Eracleous et al. and we use much longer time series for the three objects studied in that paper. Although systematic changes in radial velocity can be traced in many of their lines, they are demonstrably not like those of a spectroscopic binary in a circular orbit. Any spectroscopic binary period must therefore be much longer than the span of the monitoring (assuming a circular orbit), which in turn would require black hole masses that exceed by 1–2 orders of magnitude the values obtained for these objects using techniques such as reverberation mapping and stellar velocity dispersion. Moreover, the response of the double-peaked Balmer line profiles to fluctuations of the ionizing continuum and the shape of the Lyα profiles are incompatible with an SMBH binary. The binary broad-line region hypothesis is therefore disfavored. Other processes evidently shape these line profiles and cause the long-term velocity variations of the double peaks.

Influence of thin porous Al2O3 layer on aluminum cathode to the Hα line shape in glow discharge

International Nuclear Information System (INIS)

Steflekova, V.; Sisovic, N. M.; Konjevic, N.

2009-01-01

The results of the Balmer alfa line shape study in a plane cathode-hollow anode Grimm discharge with aluminum (Al) cathode covered with thin layer of porous Al 2 O 3 are presented. The comparison with same line profile recorded with pure Al cathode shows lack of excessive Doppler broadened line wings, which are always detected in glow discharge with metal cathode. The effect is explained by the lack of strong electric field in the cathode sheath region, which is missing in the presence of thin oxide layer in, so called, spray discharge.

Estimation of genetic variability level in inbred CF1 mouse lines ...

Indian Academy of Sciences (India)

To estimate the genetic variability levels maintained by inbred lines selected for body weight and to compare them with a nonselected population from which the lines were derived, we calculated the per cent polymorphic loci (P) and marker diversity (MD) index from data on 43 putative loci of inter simple sequence repeats ...

Complex, variable structure of stationary lines in SS433

Energy Technology Data Exchange (ETDEWEB)

Falomo, R.; Boksenberg, A.; Tanzi, E.G.; Tarenghi, M.; Treves, A.

1987-01-15

On 1979 June 3-6, a number of spectra of SS433 were obtained using the UCL Image Photon Counting System on the 3.6-m telescope of the European Southern Observatory, La Silla, Chile. The stationary H..cap alpha.. and He I lambdalambda5875, 6678 and 7065 lines have a complex structure which on June 4-5 exhibited a central feature accompanied by two equally displaced (+- 1000 km s/sup -1/) side components. Variability of the line profile and equivalent width is observed on time-scales as short as a quarter of an hour.

Diagnostics of red-shifted H-alpha line emission from a C-class flare with full non-LTE radiative and hydrodynamic approach

Science.gov (United States)

Druett, M. K.; Zharkova, V. V.; Scullion, E.; Zharkov, S.; Matthews, S. A.

2016-12-01

We analyse H-alpha line profiles with strong redshifts during the C1.8 flare on 1st July 2012 obtained from the Swedish Solar Telescope (SST) closely resembling the previous observations (Wuelser and Marti, 1989). The flare has a magnetic field configuration with two levels of loop structures. The kernels with red shifts are observed in one of the H-alpha ribbons in the south-west location formed after the main impulse recorded in the north-east. The locations of H-alpha kernels with red shifts reveal close temporal and spatial correlation with weaker HXR signatures and coincide with the locations of coronal jets observed with AIA/SDO. For interpretation we apply a revised 1D hydrodynamic and non-LTE (NLTE) radiative model for 5 level plus continuum model hydrogen atom (Druett & Zharkova, 2016) considering radiative, thermal and non-thermal excitation and ionisation by beam electrons with the updated beam densities (Zharkova & Dobranskis, 2016) and analytical excitation/ionisation rates (Zharkova& Kobylinskijj, 1993). We find the simultaneous solutions of steady state and radiative transfer equations in all optically-thick lines and continua. The electron and ion temperatures, ambient density and macrovelocity of the ambient plasma are derived from a 1D hydrodynamic model with initial condition of the pre-flaring photosphere for the two fluid ambient plasma heated by beam electrons (Zharkova & Zharkov, 2007). We simulate distributions over precipitation depth of ionisation and departure coefficients for all the hydrogen atom transitions including the deviation of ionisation from Saha equation affected by non-thermal electron beams. We show that in the very first seconds after the beam onset Balmer line profiles are sensitive to the effect of beam electrons. The combination of the additional ionisation caused by beam electrons leading to a very strong Stark effect in Balmer lines with the hydrodynamic heating and formation of a low temperature shock in the

The in-focus variable line spacing plane grating monochromator

International Nuclear Information System (INIS)

Reininger, R.

2011-01-01

The in-focus variable line spacing plane grating monochromator is based on only two plane optical elements, a variable line spacing plane grating and a plane pre-mirror that illuminates the grating at the angle of incidence that will focus the required photon energy. A high throughput beamline requires only a third optical element after the exit slit, an aberration corrected elliptical toroid. Since plane elements can be manufactured with the smallest figure errors, this monochromator design can achieve very high resolving power. Furthermore, this optical design can correct the deformations induced by the heat load on the optics along the dispersion plane. This should allow obtaining a resolution of 10 meV at 1 keV with currently achievable figure errors on plane optics. The position of the photon source when an insertion device center is not located at the center of the straight section, a common occurrence in new insertion device beamlines, is investigated.

Spectroscopic observations of the symbiotic star AG Draconis

Energy Technology Data Exchange (ETDEWEB)

Smith, S E; Bopp, B W [Toledo Univ., OH (USA)

1981-06-01

Spectroscopic observations, covering the lambdalambda 3500-7000 region, of the symbiotic star AG Draconis are reported. The Balmer and He I line profiles were found to show pronounced blueward asymmetries. Changes in the line profiles of the Balmer lines were observed, and found to be well correlated with the 554-day photometric period of Meinunger, with a second, blueward component being visible in the Balmer emissions at photometric minimum. The weak, blueshifted component in the Balmer emission lines is explained in terms of a stellar wind from the hot secondary at of the order of 60 kms s/sup -1/. The behaviour of the broad emission feature at lambda6380 has been investigated. This feature was found to originate from an ion with an ionization potential in the range 77-101 eV. Various models for AG Dra are discussed.

Electron density profile measurements from hydrogen line intensity ratio method in Versatile Experimental Spherical Torus

Energy Technology Data Exchange (ETDEWEB)

Kim, YooSung; Shi, Yue-Jiang, E-mail: yjshi@snu.ac.kr; Yang, Jeong-hun; Kim, SeongCheol; Kim, Young-Gi; Dang, Jeong-Jeung; Yang, Seongmoo; Jo, Jungmin; Chung, Kyoung-Jae [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Oh, Soo-Ghee [Division of Energy Systems Research, Ajou University, Suwon 442-749 (Korea, Republic of); Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Center for Advanced Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

2016-11-15

Electron density profiles of versatile experiment spherical torus plasmas are measured by using a hydrogen line intensity ratio method. A fast-frame visible camera with appropriate bandpass filters is used to detect images of Balmer line intensities. The unique optical system makes it possible to take images of H{sub α} and H{sub β} radiation simultaneously, with only one camera. The frame rate is 1000 fps and the spatial resolution of the system is about 0.5 cm. One-dimensional local emissivity profiles have been obtained from the toroidal line of sight with viewing dumps. An initial result for the electron density profile is presented and is in reasonable agreement with values measured by a triple Langmuir probe.

Heterogeneity of osteosarcoma cell lines led to variable responses in reprogramming.

Science.gov (United States)

Choong, Pei Feng; Teh, Hui Xin; Teoh, Hoon Koon; Ong, Han Kiat; Choo, Kong Bung; Sugii, Shigeki; Cheong, Soon Keng; Kamarul, Tunku

2014-01-01

Four osteosarcoma cell lines, Saos-2, MG-63, G-292 and U-2 OS, were reprogrammed to pluripotent state using Yamanaka factors retroviral transduction method. Embryonic stem cell (ESC)-like clusters started to appear between 15 to 20 days post transduction. Morphology of the colonies resembled that of ESC colonies with defined border and tightly-packed cells. The reprogrammed sarcomas expressed alkaline phosphatase and pluripotency markers, OCT4, SSEA4, TRA-1-60 and TRA-1-81, as in ESC up to Passage 15. All reprogrammed sarcomas could form embryoid body-like spheres when cultured in suspension in a low attachment dish for up to 10 days. Further testing on the directed differentiation capacity of the reprogrammed sarcomas showed all four reprogrammed sarcoma lines could differentiate into adipocytes while reprogrammed Saos-2-REP, MG-63-REP and G-292-REP could differentiate into osteocytes. Among the 4 osteosarcoma cell lines, U-2 OS reported the highest transduction efficiency but recorded the lowest reprogramming stability under long term culture. Thus, there may be intrinsic differences governing the variable responses of osteosarcoma cell lines towards reprogramming and long term culture effect of the reprogrammed cells. This is a first report to associate intrinsic factors in different osteosarcoma cell lines with variable reprogramming responses and effects on the reprogrammed cells after prolonged culture.

Heterogeneity of Osteosarcoma Cell Lines Led to Variable Responses in Reprogramming

Science.gov (United States)

Choong, Pei Feng; Teh, Hui Xin; Teoh, Hoon Koon; Ong, Han Kiat; Choo, Kong Bung; Sugii, Shigeki; Cheong, Soon Keng; Kamarul, Tunku

2014-01-01

Four osteosarcoma cell lines, Saos-2, MG-63, G-292 and U-2 OS, were reprogrammed to pluripotent state using Yamanaka factors retroviral transduction method. Embryonic stem cell (ESC)-like clusters started to appear between 15 to 20 days post transduction. Morphology of the colonies resembled that of ESC colonies with defined border and tightly-packed cells. The reprogrammed sarcomas expressed alkaline phosphatase and pluripotency markers, OCT4, SSEA4, TRA-1-60 and TRA-1-81, as in ESC up to Passage 15. All reprogrammed sarcomas could form embryoid body-like spheres when cultured in suspension in a low attachment dish for up to 10 days. Further testing on the directed differentiation capacity of the reprogrammed sarcomas showed all four reprogrammed sarcoma lines could differentiate into adipocytes while reprogrammed Saos-2-REP, MG-63-REP and G-292-REP could differentiate into osteocytes. Among the 4 osteosarcoma cell lines, U-2 OS reported the highest transduction efficiency but recorded the lowest reprogramming stability under long term culture. Thus, there may be intrinsic differences governing the variable responses of osteosarcoma cell lines towards reprogramming and long term culture effect of the reprogrammed cells. This is a first report to associate intrinsic factors in different osteosarcoma cell lines with variable reprogramming responses and effects on the reprogrammed cells after prolonged culture. PMID:25170299

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

International Nuclear Information System (INIS)

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

2014-01-01

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

The End of the Lines for OX 169: No Binary Broad-Line Region

Science.gov (United States)

Halpern, J. P.; Eracleous, M.

2000-03-01

We show that unusual Balmer emission-line profiles of the quasar OX 169, frequently described as either self-absorbed or double peaked, are actually neither. The effect is an illusion resulting from two coincidences. First, the forbidden lines are quite strong and broad. Consequently, the [N II] λ6583 line and the associated narrow-line component of Hα present the appearance of twin Hα peaks. Second, the redshift of 0.2110 brings Hβ into coincidence with Na I D at zero redshift, and ISM absorption in Na I D divides the Hβ emission line. In spectra obtained over the past decade, we see no substantial change in the character of the line profiles and no indication of intrinsic double-peaked structure. The Hγ, Mg II, and Lyα emission lines are single peaked, and all of the emission-line redshifts are consistent once they are correctly attributed to their permitted and forbidden-line identifications. A systematic shift of up to 700 km s-1 between broad and narrow lines is seen, but such differences are common and could be due to gravitational and transverse redshift in a low-inclination disk. Stockton & Farnham had called attention to an apparent tidal tail in the host galaxy of OX 169 and speculated that a recent merger had supplied the nucleus with a coalescing pair of black holes that was now revealing its existence in the form of two physically distinct broad-line regions. Although there is no longer any evidence for two broad emission-line regions in OX 169, binary black holes should form frequently in galaxy mergers, and it is still worthwhile to monitor the radial velocities of emission lines that could supply evidence of their existence in certain objects.

The complex, variable structure of stationary lines in SS433

International Nuclear Information System (INIS)

Falomo, R.; Boksenberg, A.; Tanzi, E.G.; Tarenghi, M.; Treves, A.

1987-01-01

On 1979 June 3-6, a number of spectra of SS433 were obtained using the UCL Image Photon Counting System on the 3.6-m telescope of the European Southern Observatory, La Silla, Chile. The stationary Hα and He I lambdalambda5875, 6678 and 7065 lines have a complex structure which on June 4-5 exhibited a central feature accompanied by two equally displaced (+- 1000 km s -1 ) side components. Variability of the line profile and equivalent width is observed on time-scales as short as a quarter of an hour. (author)

On the Use of Variability Operations in the V-Modell XT Software Process Line

DEFF Research Database (Denmark)

Kuhrmann, Marco; Méndez Fernández, Daniel; Ternité, Thomas

2016-01-01

. In this article, we present a study on the feasibility of variability operations to support the development of software process lines in the context of the V-Modell XT. We analyze which variability operations are defined and practically used. We provide an initial catalog of variability operations...... as an improvement proposal for other process models. Our findings show that 69 variability operation types are defined across several metamodel versions of which, however, 25 remain unused. The found variability operations allow for systematically modifying the content of process model elements and the process......Software process lines provide a systematic approach to develop and manage software processes. It defines a reference process containing general process assets, whereas a well-defined customization approach allows process engineers to create new process variants, e.g., by extending or modifying...

TIME VARIABILITY OF EMISSION LINES FOR FOUR ACTIVE T TAURI STARS. I. OCTOBER-DECEMBER IN 2010

Energy Technology Data Exchange (ETDEWEB)

Chou, Mei-Yin; Takami, Michihiro; Karr, Jennifer L.; Shang Hsien; Liu, Hauyu Baobab [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Manset, Nadine [Canada-France-Hawaii Telescope, 65-1238 Mamalahoa Hwy, Kamuela, HI 96743 (United States); Beck, Tracy [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Pyo, Tae-Soo [Subaru Telescope, 650 North Aohoku Place, Hilo, HI 96720 (United States); Chen, Wen-Ping; Panwar, Neelam [Institute of Astronomy, National Central University, Taoyuan County 32001, Taiwan (China)

2013-04-15

We present optical spectrophotometric monitoring of four active T Tauri stars (DG Tau, RY Tau, XZ Tau, RW Aur A) at high spectral resolution (R {approx}> 1 Multiplication-Sign 10{sup 4}), to investigate the correlation between time variable mass ejection seen in the jet/wind structure of the driving source and time variable mass accretion probed by optical emission lines. This may allow us to constrain the understanding of the jet/wind launching mechanism, the location of the launching region, and the physical link with magnetospheric mass accretion. In 2010, observations were made at six different epochs to investigate how daily and monthly variability might affect such a study. We perform comparisons between the line profiles we observed and those in the literature over a period of decades and confirm the presence of time variability separate from the daily and monthly variability during our observations. This is so far consistent with the idea that these line profiles have a long-term variability (3-20 yr) related to episodic mass ejection suggested by the structures in the extended flow components. We also investigate the correlations between equivalent widths and between luminosities for different lines. We find that these correlations are consistent with the present paradigm of steady magnetospheric mass accretion and emission line regions that are close to the star.

TIME VARIABILITY OF EMISSION LINES FOR FOUR ACTIVE T TAURI STARS. I. OCTOBER–DECEMBER IN 2010

International Nuclear Information System (INIS)

Chou, Mei-Yin; Takami, Michihiro; Karr, Jennifer L.; Shang Hsien; Liu, Hauyu Baobab; Manset, Nadine; Beck, Tracy; Pyo, Tae-Soo; Chen, Wen-Ping; Panwar, Neelam

2013-01-01

We present optical spectrophotometric monitoring of four active T Tauri stars (DG Tau, RY Tau, XZ Tau, RW Aur A) at high spectral resolution (R ∼> 1 × 10 4 ), to investigate the correlation between time variable mass ejection seen in the jet/wind structure of the driving source and time variable mass accretion probed by optical emission lines. This may allow us to constrain the understanding of the jet/wind launching mechanism, the location of the launching region, and the physical link with magnetospheric mass accretion. In 2010, observations were made at six different epochs to investigate how daily and monthly variability might affect such a study. We perform comparisons between the line profiles we observed and those in the literature over a period of decades and confirm the presence of time variability separate from the daily and monthly variability during our observations. This is so far consistent with the idea that these line profiles have a long-term variability (3-20 yr) related to episodic mass ejection suggested by the structures in the extended flow components. We also investigate the correlations between equivalent widths and between luminosities for different lines. We find that these correlations are consistent with the present paradigm of steady magnetospheric mass accretion and emission line regions that are close to the star.

An extreme Fe II emitter the narrow line quasar PHL 1092

CERN Document Server

Bergeron, J

1980-01-01

A search for Fe II emission in a sample of radio-quiet quasars has revealed the outstanding properties of PHL 1092. Intense Fe II lines dominate the entire spectrum, and the Fe II UV multiplets are nearly as strong as the optical ones. In contrast the extreme weakness of the Balmer and Mg II lines is striking. For the first time, Fe I lines are identified in an extra-galactic object. The lines are narrow, with a FWHM of 1300 km s/sup -1/. The presence of Fe II UV lines and Fe I lines from the ground state requires moderate column densities. However Fe/sup 0/ can exist only in a region completely shielded from the UV continuum. The weakness of Mg II and H beta relative to Fe II lines is best explained by their thermalization. The emitting region is of high electron density n/sub e/ approximately=10/sup 12/ cm/sup -3/, low temperature T approximately=10000K, and has an optical depth in the Fe II UV lines tau /sub UV/ approximately=10/sup 3/-10/sup 4/. It is speculated that for higher densities all the lines wou...

A NEW SUB-PERIOD-MINIMUM CATACLYSMIC VARIABLE WITH PARTIAL HYDROGEN DEPLETION AND EVIDENCE OF SPIRAL DISK STRUCTURE

International Nuclear Information System (INIS)

Littlefield, C.; Garnavich, P.; Magno, K.; Applegate, A.; Pogge, R.; Irwin, J.; Marion, G. H.; Kirshner, R.; Vinkó, J.

2013-01-01

We present time-resolved spectroscopy and photometry of CSS 120422:111127+571239 (=SBS 1108+574), a recently discovered SU UMa-type dwarf nova whose 55 minute orbital period is well below the cataclysmic variable (CV) period minimum of ∼78 minutes. In contrast with most other known CVs, its spectrum features He I emission of comparable strength to the Balmer lines, implying a hydrogen abundance less than 0.1 of long-period CVs—but still at least 10 times higher than that in AM CVn stars. Together, the short orbital period and remarkable helium-to-hydrogen ratio suggest that mass transfer in CSS 120422 began near the end of the donor star's main-sequence lifetime, meaning that this CV is a strong candidate progenitor of an AM CVn system as described by Podsiadlowski et al. Moreover, a Doppler tomogram of the Hα line reveals two distinct regions of enhanced emission. While one is the result of the stream-disk impact, the other is probably attributable to spiral disk structure generated when material in the outer disk achieves a 2:1 orbital resonance with respect to the donor.

Genotypic variability in sesame mutant lines in Kenya | Ong'injo ...

African Journals Online (AJOL)

Sesame (Sesamum indicum L) is one of the major oil crops with potential for production by small- scale holders in the marginal agro-ecological zones of Kenya. Variability studies on yield and yield components of sesame mutant lines now in M7generation was carried out in two locations for two seasons in Kenya.

SIMULTANEOUS ULTRAVIOLET AND OPTICAL EMISSION-LINE PROFILES OF QUASARS: IMPLICATIONS FOR BLACK HOLE MASS DETERMINATION

International Nuclear Information System (INIS)

Ho, Luis C.; Dong Xiaobo; Goldoni, Paolo; Ponti, Gabriele; Greene, Jenny E.

2012-01-01

The X-shooter instrument on the Very Large Telescope was used to obtain spectra of seven moderate-redshift quasars simultaneously covering the spectral range ∼3000 Å to 2.5 μm. At z ≈ 1.5, most of the prominent broad emission lines in the ultraviolet to optical region are captured in their rest frame. We use this unique data set, which mitigates complications from source variability, to intercompare the line profiles of C IV λ1549, C III] λ1909, Mg II λ2800, and Hα and evaluate their implications for black hole (BH) mass estimation. We confirm that Mg II and the Balmer lines share similar kinematics and that they deliver mutually consistent BH mass estimates with minimal internal scatter (∼<0.1 dex) using the latest virial mass estimators. Although no virial mass formalism has yet been calibrated for C III], this line does not appear promising for such an application because of the large spread of its velocity width compared to lines of both higher and lower ionization; part of the discrepancy may be due to the difficulty of deblending C III] from its neighboring lines. The situation for C IV is complex and, because of the limited statistics of our small sample, inconclusive. On the one hand, slightly more than half of our sample (4/7) have C IV line widths that correlate reasonably well with Hα line widths, and their respective BH mass estimates agree to within ∼0.15 dex. The rest, on the other hand, exhibit exceptionally broad C IV profiles that overestimate virial masses by factors of 2-5 compared to Hα. As C IV is widely used to study BH demographics at high redshifts, we urgently need to revisit our analysis with a larger sample.

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-11-10

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

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

International Nuclear Information System (INIS)

Peterson, B. M.; Denney, K. D.; De Rosa, G.; Grier, C. J.; Pogge, R. W.; Kochanek, C. S.; Bentz, M. C.; Vestergaard, M.; Kilerci-Eser, E.; G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" data-affiliation=" (Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" >Dalla Bontà, E.; G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" data-affiliation=" (Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" >Ciroi, S.

2013-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Peterson, B. M.; Denney, K. D.; De Rosa, G.; Grier, C. J.; Pogge, R. W.; Kochanek, C. S. [Department of Astronomy, The Ohio State University, 140 W 18th Avenue, Columbus, OH 43210 (United States); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, 25 Park Place, Suite 610, Atlanta, GA 30303 (United States); Vestergaard, M.; Kilerci-Eser, E. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Dalla Bontà, E.; Ciroi, S. [Dipartimento di Fisica e Astronomia " G. Galilei," Università di Padova, Vicolo dell' Osservatorio 3 I-35122, Padova (Italy)

2013-12-20

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

Long-term spectroscopic monitoring of the Luminous Blue Variable AG Carinae

Science.gov (United States)

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

Hydrogen line formation in the quescent prominences

International Nuclear Information System (INIS)

Tsovookhuu, Ch.

1980-01-01

Equations of transfer and statistical equilibrium for hydronen atom with eight bound levels and continuum are solved simultaneously. A plane-parallel layer located perpendicular to the Sun surface is taken as a geometrical model. Input parameters of the physical model are optical thickness in the center of Hsub(α) line, electron temperature and concentration in the layer center are well as temperature and density gradients. Functions of sources, line profiles, total energies and the Balmer decrements, which are compared with observations and theoretical calculations made by other authors, have been calculated. The comparison shows that the results are quite acceptable and can be used when analyzing the spectrum and determining physical parameters of solar prominences. Dependence of different performances of the line (equivalent width, central intensity, halfwidth, depth of central depression etc.) on values of initial model parameters is investigated. Line halfwidth is more sensitive to the temperatuu value in the layer center, while central intensity - to the value of temperature gradient and a depth of central depression - to electron concentration. Calculated were shares of primary sources responsible for different excitation mechanism depending on total optical thickness as well as mean probabilities of quantum yield out of a medium which can be used during parametric accountancy of radiation diffusion in solar prominences [ru

X-ray heating and ionization of broad-emission-line regions in QSO's and active galaxies

International Nuclear Information System (INIS)

Weisheit, J.C.; Shields, G.A.; Tarter, C.B.

1980-07-01

Absorption of x-rays deep within the broad-line emitting clouds in QSO's and the nuclei of active galaxies creates extensive zones of warm (T approx. 10 4 K), partially ionized N/sub e//N approx. 0.1) gas. Because Lyman alpha photons are trapped in these regions, the x-ray energy is efficiently channeled into Balmer lines collisionally excited from the n = 2 level. The HI regions plus the HII regions created by ultraviolet photons illuminating the surfaces of the clouds give rise to integrated Lα/Hα line emission ratios between 1 and 2. Enhanced MgII line emission from the HI regions gives rise to integrated MgII/Hα ratios near 0.5. The OI line lambda 8446 is efficiently pumped by trapped Hα photons and in the x-ray heated zone an intensity ratio I (lambda 8446)/I(Hα) approx. < 0.1 is calculated. All of these computed ratios now are in agreement with observations

Evaluating Genetic Variability of Sorghum Mutant Lines Tolerant to Acid Soil

International Nuclear Information System (INIS)

Puspitasari, W.; Human, S.; Wirnas, D.; Trikoesoemaningtyas

2012-01-01

High rainfall in some parts in Indonesia causes soil become acidic. The main constraint of acid soil is phosphor (P) deficiency and aluminum (Al) toxicity which decrease plant productivity. To overcome this problem, it is important to develop a crop variety tolerant to such conditions. Sorghum is probably one of the potential crops to meet that objective. Sorghum has been reported to have wide adaptability to various agro-ecology and can be used as food and animal feed. Unfortunately, sorghum is not Indonesian origin so its genetic variability is still low. From previous breeding works with induced mutation, some promising mutant lines have been developed. These mutant lines were included in the experiment carried out in Tenjo with soil condition was classified as acid soil with pH 4.8 and exchangeable-Al content 2.43 me/100 g. The objectives of this experiment were to study the magnitude of genetic variability of agronomy and grain quality characters in sorghum in order to facilitate the breeding improvement of the species. Plant materials used in this study were ten genotypes, including 6 mutant lines and 4 control varieties. The randomized block design with three replications was used in the experiment. The genetic variabilities of agronomic and grain quality characters existed among genotypes, such as plant height, number of leaves, stalk diameter, biomass weight, panicle length, grain yield per plant, 100 seed weight and tannin content in the grain. The broad sense heritabilities of agronomic characters were estimated ranging from medium to high. Grain yield showed significantly positive correlation with agronomic characters observed, but it was negatively correlated with protein content (author)

The central star candidate of the planetary nebula Sh2-71: photometric and spectroscopic variability

Science.gov (United States)

Močnik, T.; Lloyd, M.; Pollacco, D.; Street, R. A.

2015-07-01

We present the analysis of several newly obtained and archived photometric and spectroscopic data sets of the intriguing and yet poorly understood 13.5 mag central star candidate of the bipolar planetary nebula Sh2-71. Photometric observations confirmed the previously determined quasi-sinusoidal light curve with a period of 68 d and also indicated periodic sharp brightness dips, possibly eclipses, with a period of 17.2 d. In addition, the comparison between U and V light curves revealed that the 68 d brightness variations are accompanied by a variable reddening effect of ΔE(U - V) = 0.38. Spectroscopic data sets demonstrated pronounced variations in spectral profiles of Balmer, helium and singly ionized metal lines and indicated that these variations occur on a time-scale of a few days. The most accurate verification to date revealed that spectral variability is not correlated with the 68 d brightness variations. The mean radial velocity of the observed star was measured to be ˜26 km s-1 with an amplitude of ±40 km s-1. The spectral type was determined to be B8V through spectral comparison with synthetic and standard spectra. The newly proposed model for the central star candidate is a Be binary with a misaligned precessing disc.

Optical spectral properties of active galactic nuclei and quasars

International Nuclear Information System (INIS)

Yee, H.K.C.

1981-01-01

Four separate investigations dealing with the properties of optical continuum and emission-lines of active galactic nuclei (AGN) and quasars are presented. Multichannel scans of 3CR radio galaxies are decomposed by using a two-component model-an elliptical galaxy and a power-law nonthermal component. It is found that there is a strong correlation between the luminosity of the power-law component and the strength of the Balmer emission-lines. In most cases, by extrapolating to the Lyman continuum, the power-law models derived provide enough ionizing radiation to account for the Balmer line strengths. Extending the study of radio galaxies to include Seyfert galaxies and quasars, it is found that there is a strong continuity between broad-line AGN's and quasars in terms of similarities in the correlations between line luminosities and nonthermal continuum luminosity. Next, a study of the variability of absolute optical energy distribution and emission-lines of the N-galaxies 3C382 and 3C390.3 is made. Lastly, a preliminary study of surface photometry of Markarian Seyfert galaxies are presented. It is found that the properties of the underlying galaxies such as scale-length and surface brightness of the disk, color, and total brightness, do not depart systematically from those of luminous normal spiral galaxies

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

International Nuclear Information System (INIS)

Grier, C. J.; Brandt, W. N.; Trump, J. R.; Schneider, D. P.; Hall, P. B.; Shen, Yue; Vivek, M.; Dawson, K. S.; Ak, N. Filiz; Chen, Yuguang; Denney, K. D.; Kochanek, C. S.; Peterson, B. M.; Green, Paul J.; Jiang, Linhua; McGreer, Ian D.; Pâris, I.; Tao, Charling; Wood-Vasey, W. M.; Bizyaev, Dmitry

2015-01-01

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 −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% 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 e ≳ 3.9 × 10 5 cm −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

Universal FFM Hydrogen Spectral Line Shapes Applied to Ions and Electrons

Science.gov (United States)

Mossé, C.; Calisti, A.; Ferri, S.; Talin, B.; Bureyeva, L. A.; Lisitsa, V. S.

2008-10-01

We present a method for the calculation of hydrogen spectral line shapes based on two combined approaches: Universal Model and FFM procedure. We start with the analytical functions for the intensities of the Stark components of radiative transitions between highly excited atomic states with large values of principal quantum numbers n,n'γ1, with Δn = n-n'≪n for the specific cases of Hn-α line (Δn = 1) and Hn-β line (Δn = 2). The FFM line shape is obtained by averaging on the electric field of the Hooper's field distribution for ion and electron perturber dynamics and by mixing the Stark components with a jumping frequency rate ve (vi) where v = N1/3u (N is electron density and u is the ion or electron thermal velocity). Finally, the total line shape is given by convolution of ion and electron line shapes. Hydrogen line shape calculations for Balmer Hα and Hβ lines are compared to experimental results in low density plasma (Ne˜1016-1017cm-3) and low electron temperature in order of 10 000K. This method relying on analytic expressions permits fast calculation of Hn-α and Hn-β lines of hydrogen and could be used in the study of the Stark broadening of radio recombination lines for high principal quantum number.

High-cadence, High-resolution Spectroscopic Observations of Herbig Stars HD 98922 and V1295 Aquila

Energy Technology Data Exchange (ETDEWEB)

Aarnio, Alicia N.; Monnier, John D.; Calvet, Nuria; Che, Xiao [Department of Astronomy, University of Michigan, 311 West Hall, 1085 S. University Avenue, Ann Arbor, MI 48109 (United States); Harries, Tim J.; Kraus, Stefan; Acreman, David [Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom)

2017-10-10

Recent observational work has indicated that mechanisms for accretion and outflow in Herbig Ae/Be star–disk systems may differ from magnetospheric accretion (MA) as it is thought to occur in T Tauri star–disk systems. In this work, we assess the temporal evolution of spectral lines probing accretion and mass loss in Herbig Ae/Be systems and test for consistency with the MA paradigm. For two Herbig Ae/Be stars, HD 98922 (B9e) and V1295 Aql (A2e), we have gathered multi-epoch (∼years) and high-cadence (∼minutes) high-resolution optical spectra to probe a wide range of kinematic processes. Employing a line equivalent width evolution correlation metric introduced here, we identify species co-evolving (indicative of common line origin) via novel visualization. We interferometrically constrain often problematically degenerate parameters, inclination and inner-disk radius, allowing us to focus on the structure of the wind, magnetosphere, and inner gaseous disk in radiative transfer models. Over all timescales sampled, the strongest variability occurs within the blueshifted absorption components of the Balmer series lines; the strength of variability increases with the cadence of the observations. Finally, high-resolution spectra allow us to probe substructure within the Balmer series’ blueshifted absorption components: we observe static, low-velocity features and time-evolving features at higher velocities. Overall, we find the observed line morphologies and variability are inconsistent with a scaled-up T Tauri MA scenario. We suggest that as magnetic field structure and strength change dramatically with increasing stellar mass from T Tauri to Herbig Ae/Be stars, so too may accretion and outflow processes.

High-cadence, High-resolution Spectroscopic Observations of Herbig Stars HD 98922 and V1295 Aquila

International Nuclear Information System (INIS)

Aarnio, Alicia N.; Monnier, John D.; Calvet, Nuria; Che, Xiao; Harries, Tim J.; Kraus, Stefan; Acreman, David

2017-01-01

Recent observational work has indicated that mechanisms for accretion and outflow in Herbig Ae/Be star–disk systems may differ from magnetospheric accretion (MA) as it is thought to occur in T Tauri star–disk systems. In this work, we assess the temporal evolution of spectral lines probing accretion and mass loss in Herbig Ae/Be systems and test for consistency with the MA paradigm. For two Herbig Ae/Be stars, HD 98922 (B9e) and V1295 Aql (A2e), we have gathered multi-epoch (∼years) and high-cadence (∼minutes) high-resolution optical spectra to probe a wide range of kinematic processes. Employing a line equivalent width evolution correlation metric introduced here, we identify species co-evolving (indicative of common line origin) via novel visualization. We interferometrically constrain often problematically degenerate parameters, inclination and inner-disk radius, allowing us to focus on the structure of the wind, magnetosphere, and inner gaseous disk in radiative transfer models. Over all timescales sampled, the strongest variability occurs within the blueshifted absorption components of the Balmer series lines; the strength of variability increases with the cadence of the observations. Finally, high-resolution spectra allow us to probe substructure within the Balmer series’ blueshifted absorption components: we observe static, low-velocity features and time-evolving features at higher velocities. Overall, we find the observed line morphologies and variability are inconsistent with a scaled-up T Tauri MA scenario. We suggest that as magnetic field structure and strength change dramatically with increasing stellar mass from T Tauri to Herbig Ae/Be stars, so too may accretion and outflow processes.

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

Energy Technology Data Exchange (ETDEWEB)

Grier, C. J.; Brandt, W. N.; Trump, J. R.; Schneider, D. P. [Department of Astronomy and Astrophysics and Institute for Gravitation and the Cosmos, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Hall, P. B. [Department of Physics and Astronomy, York University, Toronto, ON M3J 1P3 (Canada); Shen, Yue [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Vivek, M.; Dawson, K. S. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Ak, N. Filiz [Faculty of Sciences, Department of Astronomy and Space Sciences, Erciyes University, 38039 Kayseri (Turkey); Chen, Yuguang [Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China); Denney, K. D.; Kochanek, C. S.; Peterson, B. M. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Green, Paul J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Jiang, Linhua [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); McGreer, Ian D. [Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States); Pâris, I. [INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, I-34131 Trieste (Italy); Tao, Charling [Centre de Physique des Particules de Marseille, Aix-Marseille Universite, CNRS /IN2P3, 163, avenue de Luminy, Case 902, F-13288 Marseille Cedex 09 (France); Wood-Vasey, W. M. [PITT PACC, Department of Physics and Astronomy, University of Pittsburgh, 3941 O’Hara Street, Pittsburgh, PA 15260 (United States); Bizyaev, Dmitry, E-mail: grier@psu.edu [Apache Point Observatory and New Mexico State University, P.O. Box 59, Sunspot, NM, 88349-0059 (United States); and others

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% 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.

Comparison of semen variables, sperm DNA damage and sperm membrane proteins in two male layer breeder lines.

Science.gov (United States)

M, Shanmugam; T R, Kannaki; A, Vinoth

2016-09-01

Semen variables are affected by the breed and strain of chicken. The present study was undertaken to compare the semen quality in two lines of adult chickens with particular reference to sperm chromatin condensation, sperm DNA damage and sperm membrane proteins. Semen from a PD3 and White Leghorn control line was collected at 46 and 47 weeks and 55 weeks of age. The semen was evaluated for gross variables and sperm chromatin condensation by aniline blue staining. Sperm DNA damage was assessed by using the comet assay at 47 weeks of age and sperm membrane proteins were assessed at 55 weeks of age. The duration of fertility was studied by inseminating 100 million sperm once into the hens of the same line as well as another line. The eggs were collected after insemination for 15days and incubated. The eggs were candled on 18th day of incubation for observing embryonic development. The White Leghorn control line had a greater sperm concentration and lesser percentage of morphologically abnormal sperm at the different ages where assessments occurred. There was no difference in sperm chromatin condensation, DNA damage and membrane proteins between the lines. Only low molecular weight protein bands of less than 95kDa were observed in samples of both lines. The line from which semen was used had no effect on the duration over which fertility was sustained after insemination either when used in the same line or another line. Thus, from the results of the present study it may be concluded that there was a difference in gross semen variables between the lines that were studied, however, the sperm chromatin condensation, DNA damage, membrane proteins and duration over which fertility was sustained after insemination did not differ between the lines. Copyright © 2016 Elsevier B.V. All rights reserved.

MULTIWAVELENGTH VARIABILITY OF THE BROAD LINE RADIO GALAXY 3C 120

International Nuclear Information System (INIS)

Marshall, Kevin; Ryle, Wesley T.; Miller, H. Richard; Marscher, Alan P.; Jorstad, Svetlana G.; Chicka, Benjamin; McHardy, Ian M.

2009-01-01

We present results from a multiyear monitoring campaign of the broad-line radio galaxy 3C 120, using the Rossi X-ray Timing Explorer for nearly five years of observations. Additionally, we present coincident optical monitoring using data from several ground-based observatories. Both the X-ray and optical emission are highly variable and appear to be strongly correlated, with the X-ray emission leading the optical by 28 days. The X-ray power density spectrum is best fit by a broken power law, with a low-frequency slope of -1.2, breaking to a high-frequency slope of -2.1, and a break frequency of log ν b = -5.75 Hz, or 6.5 days. This value agrees well with the value expected based on 3C 120's mass and accretion rate. We find no evidence for a second break in the power spectrum. Combined with a moderately soft X-ray spectrum (Γ = 1.8) and a moderately high accretion rate, this indicates that 3C 120 fits in well with the high/soft variability state found in most other active galactic nuclei. Previous studies have shown that the spectrum has a strong Fe Kα line, which may be relativistically broadened. The presence of this line, combined with a power spectrum similar to that seen in Seyfert galaxies, suggests that the majority of the X-ray emission in this object arises in or near the disk, and not in the jet.

LINE-1 hypomethylation in cancer is highly variable and inversely correlated with microsatellite instability.

Directory of Open Access Journals (Sweden)

Marcos R H Estécio

2007-05-01

Full Text Available Alterations in DNA methylation in cancer include global hypomethylation and gene-specific hypermethylation. It is not clear whether these two epigenetic errors are mechanistically linked or occur independently. This study was performed to determine the relationship between DNA hypomethylation, hypermethylation and microsatellite instability in cancer.We examined 61 cancer cell lines and 60 colorectal carcinomas and their adjacent tissues using LINE-1 bisulfite-PCR as a surrogate for global demethylation. Colorectal carcinomas with sporadic microsatellite instability (MSI, most of which are due to a CpG island methylation phenotype (CIMP and associated MLH1 promoter methylation, showed in average no difference in LINE-1 methylation between normal adjacent and cancer tissues. Interestingly, some tumor samples in this group showed increase in LINE-1 methylation. In contrast, MSI-showed a significant decrease in LINE-1 methylation between normal adjacent and cancer tissues (P<0.001. Microarray analysis of repetitive element methylation confirmed this observation and showed a high degree of variability in hypomethylation between samples. Additionally, unsupervised hierarchical clustering identified a group of highly hypomethylated tumors, composed mostly of tumors without microsatellite instability. We extended LINE-1 analysis to cancer cell lines from different tissues and found that 50/61 were hypomethylated compared to peripheral blood lymphocytes and normal colon mucosa. Interestingly, these cancer cell lines also exhibited a large variation in demethylation, which was tissue-specific and thus unlikely to be resultant from a stochastic process.Global hypomethylation is partially reversed in cancers with microsatellite instability and also shows high variability in cancer, which may reflect alternative progression pathways in cancer.

Development of a plug-in for Variability Modeling in Software Product Lines

Directory of Open Access Journals (Sweden)

María Lucía López-Araujo

2012-03-01

Full Text Available Las Líneas de Productos de Software (LPS toman ventaja económica de las similitudes y variación entre un conjunto de sistemas de software dentro de un dominio específico. La Ingeniería de Líneas de Productos de Software por lo tanto, define una serie de procesos para el desarrollo de LPS que consideran las similitudes y variación a lo largo del ciclo devida. El modelado de variabilidad, en consecuencia, es una actividad esencial en un enfoque de Ingeniería de Líneas de Productos de Software. Existen varias técnicas para modelado de variabilidad. Entre ellas resalta COVAMOF que permite modelar los puntos de variación, variantes y dependencias como entidades de primera clase, proporcionando una manera uniforme de representarlos en los diversos niveles de abstracción de una LPS. Para poder aprovechar los beneficios de COVAMOF es necesario contar con una herramienta, de otra manera el modelado y la administración de la variabilidad pueden resultar una labor ardua para el ingeniero de software. Este trabajo presenta el desarrollo de un plug-in de COVAMOF para Eclipse.Software Product Lines (SPL take economic advantage of commonality and variability among a set of software systems that exist within a specific domain. Therefore, Software Product Line Engineering defines a series of processes for the development of a SPL that consider commonality and variability during the software life cycle. Variability modeling is therefore an essential activity in a Software Product Line Engineering approach. There are several techniques for variability modeling nowadays. COVAMOF stands out among them since it allows the modeling of variation points, variants and dependencies as first class elements. COVAMOF, therefore, provides an uniform manner for representing such concepts in different levels of abstraction within a SPL. In order to take advantage of COVAMOF benefits, it is necessary to have a computer aided tool, otherwise variability modeling and

DPLFW: a Framework for the Product-Line-Based Generation of Variable Content Documents

OpenAIRE

Gómez , Abel; Martí , Pau; Penadés , M. Carmen; Canós , José H.

2014-01-01

International audience; Document Product Lines (DPL) is a document engineering methodology that applies product-line engineering principles to the gen-eration of documents in high variability contexts and with high reuse of components. Instead of standalone documents, DPL promotes the defi-nition of families of documents where the members share some common content while differ in other parts. The key for the definition is the avail-ability of a collection of content assets which can be parame...

Outer atmospheres of cool stars. XII - A survey of IUE ultraviolet emission line spectra of cool dwarf stars

Science.gov (United States)

Linsky, J. L.; Bornmann, P. L.; Carpenter, K. G.; Hege, E. K.; Wing, R. F.; Giampapa, M. S.; Worden, S. P.

1982-01-01

Quantitative information is obtained on the chromospheres and transition regions of M dwarf stars, in order to determine how the outer atmospheres of dMe stars differ from dM stars and how they compare with the outer atmospheres of quiet and active G and K type dwarfs. IUE spectra of six dMe and four dM stars, together with ground-based photometry and spectroscopy of the Balmer and Ca II H and K lines, show no evidence of flares. It is concluded, regarding the quiescent behavior of these stars, that emission-line spectra resemble that of the sun and contain emission lines formed in regions with 4000-20,000 K temperatures that are presumably analogous to the solar chromosphere, as well as regions with temperatures of 20,000-200,000 K that are presumably analogous to the solar transition region. Emission-line surface fluxes are proportional to the emission measure over the range of temperatures at which the lines are formed.

Emission lines in the hydrogen-deficient variable MV Sagittarii near maximum light

International Nuclear Information System (INIS)

Herbig, G.H.

1975-01-01

The H-deficient R CrB type variable MV Sgr near maximum light shows a rich emission spectrum in the 5800--8600 A region. Most of these lines are due to Fe ii, but Si ii, N i, O i, and Hα also are present. Such a spectrum has not been observed in any other R CrB star, but there is some resemblance to v Sgr. The emission lines in MV Sgr probably originate in an extended region of low temperature, which may also be responsible for the infrared excess observed by Feast and Glass

Novel plasma source for safe beryllium spectral line studies in the presence of beryllium dust

Science.gov (United States)

Stankov, B. D.; Vinić, M.; Gavrilović Božović, M. R.; Ivković, M.

2018-05-01

Plasma source for beryllium spectral line studies in the presence of beryllium dust particles was realised. The guideline during construction was to prevent exposure to formed dust, considering the toxicity of beryllium. Plasma source characterization through determination of optimal working conditions is described. The necessary conditions for Be spectral line appearance and optimal conditions for line shape measurements are found. It is proven experimentally that under these conditions dust appears coincidently with the second current maximum. The electron density measured after discharge current maximum is determined from the peak separation of the hydrogen Balmer beta spectral line, and the electron temperature is determined from the ratios of the relative intensities of Be spectral lines emitted from successive ionized stages of atoms. Maximum values of electron density and temperature are measured to be 9.3 × 1022 m-3 and 16 800 K, respectively. Construction details and testing of the BeO discharge tube in comparison with SiO2 and Al2O3 discharge tubes are also presented in this paper.

IUE observations of circumstellar emission from the late-type variable R AQR (M6 + pec)

Science.gov (United States)

Hobbs, R. W.; Michalitsianos, A. G.; Kafatos, M.

1981-01-01

The IUE observations of R Aqr (M7 + pec) obtained in low dispersion are discussed with particular reference to circumstellar emission. Strong permitted, semiforbidden, and forbidden emission lines are seen, superimposed on a bright ultraviolet continuum. It is deduced that the strong emission line spectrum that involves C III, C IV, Si III, (0 II) and (0 III) probably arises from a dense compact nebula the size of which is comparable to the orbital radius of the binary system of which R Aqr is the primary star. The low excitation emission lines of Fe II, Mg II, 0 I, and Si II probably a white dwarf, comparable to or somewhat brighter than the Sun, since such a star can produce enough ionizing photons to excite the continuum and emission line spectrum and yet be sufficiently faint as to escape detection by direct observation. The UV continuum is attributed to Balmer recombination from the dense nebula and not to blackbody emission from the hot companion.

REDSHIFT EVOLUTION IN BLACK HOLE-BULGE RELATIONS: TESTING C IV-BASED BLACK HOLE MASSES

International Nuclear Information System (INIS)

Greene, Jenny E.; Peng, Chien Y.; Ludwig, Randi R.

2010-01-01

We re-examine claims for redshift evolution in black hole-bulge scaling relations based on lensed quasars. In particular, we refine the black hole (BH) mass estimates using measurements of Balmer lines from near-infrared spectroscopy obtained with Triplespec at Apache Point Observatory. In support of previous work, we find a large scatter between Balmer and UV line widths, both Mg IIλλ2796, 2803 and C IVλλ1548, 1550. There is tentative evidence that C III]λ1909, despite being a blend of multiple transitions, may correlate well with Mg II, although a larger sample is needed for a real calibration. Most importantly, we find no systematic changes in the estimated BH masses for the lensed sample based on Balmer lines, providing additional support to the interpretation that black holes were overly massive compared to their host galaxies at high redshift.

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

Science.gov (United States)

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

2013-06-01

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

COLLISIONLESS SHOCKS IN A PARTIALLY IONIZED MEDIUM. III. EFFICIENT COSMIC RAY ACCELERATION

Energy Technology Data Exchange (ETDEWEB)

Morlino, G.; Blasi, P.; Bandiera, R.; Amato, E. [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi, 5, I-50125 Firenze (Italy); Caprioli, D. [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States)

2013-05-10

In this paper, we present the first formulation of the theory of nonlinear particle acceleration in collisionless shocks in the presence of neutral hydrogen in the acceleration region. The dynamical reaction of the accelerated particles, the magnetic field amplification, and the magnetic dynamical effects on the shock are also included. The main new aspect of this study, however, consists of accounting for charge exchange and the ionization of a neutral hydrogen, which profoundly change the structure of the shock, as discussed in our previous work. This important dynamical effect of neutrals is mainly associated with the so-called neutral return flux, namely the return of hot neutrals from the downstream region to upstream, where they deposit energy and momentum through charge exchange and ionization. We also present the self-consistent calculation of Balmer line emission from the shock region and discuss how to use measurements of the anomalous width of the different components of the Balmer line to infer cosmic ray acceleration efficiency in supernova remnants showing Balmer emission: the broad Balmer line, which is due to charge exchange of hydrogen atoms with hot ions downstream of the shock, is shown to become narrower as a result of the energy drainage into cosmic rays, while the narrow Balmer line, due to charge exchange in the cosmic-ray-induced precursor, is shown to become broader. In addition to these two well-known components, the neutral return flux leads to the formation of a third component with an intermediate width: this too contains information on ongoing processes at the shock.

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

Science.gov (United States)

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

2006-01-01

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

Optical variability of the Seyfert galaxy nuclei

International Nuclear Information System (INIS)

Lyutyj, V.M.

1979-01-01

The results of the UBV observations of compact Seyfert galaxies during 1968-78 are given. The full amplitude ΔB approximately 2sup(m) of the variability of the nucleus of 3C 120 is considerably larger than that of any other Seyfert galaxy. The minimum brightness of 3C 120 in 1978, B=16sup(m).25 was observed for the first time during the photometric history of the object since 1900. The time delay Δt < or approximately 70sup(d) of the variability of colour index U-B of the nucleus of 3C 120 relatively to that of B and B-V have been discovered. This time delay is interpreted as the variability of the Balmer continuum. The nucleus of 2 Zw 136 appears to show such a variability also. The location of 3C 120 and 2 Zw 136 on two-colour diagram corresponds to the combined colours of hot (05) and cold (K-M) stars, if the time delay of U-B variability is taken into account. The colour indices of the nucleus of 3C 120 during the minimum of 1978 (B=16sup(m).25) correspond to those of the ring between the 7''-30'' apertures. This indicates to a very small contributions of the variable source during the 1978 minimum

Intra-night optical variability properties of X-ray bright Narrow-line Seyfert 1 galaxies

Science.gov (United States)

Ojha, Vineet; Chand, Hum; Gopal-Krishna

2018-04-01

We present Intra Night Optical Variability (INOV) study of the 9 Narrow-line Seyfert 1 (NLSy 1) galaxies which are detected in X-ray at more than 3σ level. Our observations cover a total of 9 nights ( 36 hr) with each NLSy 1 monitored for ≥ 3.5 hr in each night. After applying F-test to assess variability status of these sources, we found none of these sources to be variable. Such non-variability nature of X-ray detected NLSy 1 galaxies suggests the lack of jet dominance as far as X-ray emission is concerned. Higher photometric accuracy for these faint sources, achievable with the newly installed ARIES 3.6m DOT will be helpful.

Correlation between Balmer α emission and hydrogen flux through a superpermeable niobium membrane in a low-pressure multicusp plasma source

International Nuclear Information System (INIS)

Bruneteau, A.M.; Notkin, M.E.; Livshits, A.I.; Bacal, M.

2002-01-01

The purpose of this paper is to correlate hydrogen or deuterium flux through super permeable membranes with incident hydrogen or deuterium atom flux from the plasma. To this aim a hydrogen or deuterium plasma is created in a hybrid multicusp plasma source. We investigate Balmer α emission from the multicusp plasma and the output pressure behind a superpermeable niobium membrane immersed in the plasma.The output pressure is proportional to the flux of atoms and ions arriving on the membrane. We find that both output pressure and excited atoms emission satisfy plasma parameters relations. It is thus verified that plasma-driven superpermeation of hydrogen is due essentially to neutral atoms from the plasma incident to the membrane

Disc structure and variability in dwarf novae

Science.gov (United States)

Harlaftis, Emilios Theofanus

An introduction is given to dwarf novae reviewing the current research status in the field. We present IUE observations of Z Cha which support the mass transfer instability as the cause of the superoutbursts observed in SU UMa type dwarf novae. Comparison between the superoutburst and a normal outburst of Z Cha shows that the disc is flatter and has significantly less azimuthal structure than during superoutburst. Z Cha exhibits a soft x-ray deficit during superoutburst compared to OY Car. We find that the secondary star of Z Cha contributes approximately 30 percent of the infrared flux at peak of outburst. The second part of the thesis presents results from the 1988 International Time Project at the Observatorio del Roque de los Muchachos. Investigation of the behavior of SU UMa and YZ Cnc is carried out through the outburst cycle. The secular changes of the equivalent widths of both systems shows an increasing trend even during quiescence and are caused by the continuum decrease. Both systems show a low-velocity emission component which contaminates the wings of the H(alpha) profile. In addition to doppler broadening, the Stark effect is found to cause significant broadening to the line profile. The radial dependence of the emission lines is discussed in relation to other cataclysmic variables. H(alpha) emission from the secondary star of YZ Cnc is found during superoutburst, during outburst and during quiescence after outburst. Photometry during late decline of outburst shows a sinusoidal, weak variation peaking at 0.5 orbital phase and which is related to heating of the red star or to a transient disc event. During quiescence, the flickering is found to be caused by the bright spot. This modulation increases with time and is maximum before the outburst. Doppler tomography of IP Peg during quiescence reveals an emission line distribution not consistent to the standard model. We find Balmer emission from the secondary star, at a level of only 2.5 percent of the

Identification of Variables and Factors Impacting Consumer Behavior in On-line Shopping in India: An Empirical Study

Science.gov (United States)

Chhikara, Sudesh

On-line shopping is a recent phenomenon in the field of E-Business and is definitely going to be the future of shopping in the world. Most of the companies are running their on-line portals to sell their products/services. Though online shopping is very common outside India, its growth in Indian Market, which is a large and strategic consumer market, is still not in line with the global market. The potential growth of on-line shopping has triggered the idea of conducting a study on on-line shopping in India. The present research paper has used exploratory study to depict and highlight the various categories of factors and variables impacting the behavior of consumers towards on-line shopping in India. The data was collected through in-depth interviews on a sample of 41 respondents from Delhi, Mumbai, Chennai and Bangalore. The results of the study show that on-line shopping in India is basically impacted by five categories of factors like demographics factor, Psychographics factor, Online shopping feature and policies, Technological factor, Security factor. The results of the study are used to present a comprehensive model of on-line shopping which could be further used by the researchers and practitioners for conducting future studies in the similar area. A brief operational definition of all the factors and variables impacting on-line shopping in India is also described. And finally practical implications of the study are also elucidated.

Sources of Variability in the Detection of B-Lines, Using Lung Ultrasound.

Science.gov (United States)

Pivetta, Emanuele; Baldassa, Federico; Masellis, Serena; Bovaro, Federica; Lupia, Enrico; Maule, Milena M

2018-06-01

Lung ultrasound (LUS) is a largely employed diagnostic tool but an operational protocol for implementation has never been proposed. The lack of standardization clearly introduces variability in LUS results. We enrolled adult patients presenting for acute dyspnea with a clinical suspect of etiology related to heart failure. We calculated agreement among four providers in assessing B-lines. We varied probes, depth, evaluation time and scanning areas and we estimated the importance of each factors on B-lines assessment. Overall agreement among raters varied from a kappa of 0.70 to 0.81. The mean number of B-lines was 5.44 (95% confidence interval, CI, 4.1-6.8). This estimate did not suffer variation by the depth used (0.03, 95% CI -0.2-0.2, more B-lines, using 19 cm versus 10 cm). The use of a convex probe and expertise in LUS reduced the number of artifacts by 1.7 (95% CI 1.5-1.9) and 1.1 in comparison with a phased array probe and naive operators. Evaluation time increased estimates by 1.2 (95% CI 1-1.5) and 2.9 (95% CI 2.7-3.9) B-lines for 4" and 7" clips (reference was 2" clips). This study suggests that the probe, the evaluation time and the level of expertise might affect the results of quantitative assessment of B-lines. Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.

Variable blurred reflection in the narrow-line Seyfert 1 galaxy Mrk 493

Science.gov (United States)

Bonson, K.; Gallo, L. C.; Wilkins, D. R.; Fabian, A. C.

2018-04-01

We examine a 200 ks XMM-Newton observation of the narrow-line Seyfert 1 galaxy Mrk 493. The active galaxy was half as bright as in a previous 2003 snapshot observation and the current lower flux enables a study of the putative reflection component in detail. We determine the characteristics of the 2015 X-ray continuum by first analyzing the short-term variability using model-independent techniques. We then continue with a time-resolve analysis including spectral fitting and modelling the fractional variability. We determine that the variability arises from changes in the amount of primary flux striking the accretion disk, which induces changes in the ionization parameter and flux of the blurred reflection component. The observations seem consistent with the picture that the primary source is of roughly constant brightness and that variations arise from changes in the degree of light bending happening in the vicinity of the supermassive black hole.

Variability induced by spaceflight environment on high oil and normal maize lines

International Nuclear Information System (INIS)

Xu Xiaowei; Xu Li; Dong Xin; Jin Weiwei; Chen Shaojiang

2011-01-01

High oil inbred line BY815 and two normal inbred lines 1145 and F349 treated with spaceflight were used for variability analysis. Results showed that the mutation rate of BY815 was 21.61% in SP 1 , while the mutation rates of 1145 and F349 were 2.57% and 3.13% respectively. Only six mutants were found from these three materials in SP 2 , of which two mutants, HT-3 from BY815 exhibiting albino leaf color and HT-5 from 1145 exhibiting stripe-like spots leaves, were worthy of further study. Genetic analysis of the two mutants showed that the segregation ratio of normal and mutant phenotypes was 3 : 1, which was in accordance with Mendel's single gene inheritance law. Cytological observation of all the six mutants showed no chromosome abnormalities. By using SSR (simple sequence repeat) method, 130 pairs of primers were employed and only one mutant originated from inbred line 1145 showed polymorphic and the mutated loci rate of the genome in this mutant was 8.46%. (authors)

Low resolution infrared spectra of quasars

International Nuclear Information System (INIS)

Soifer, B.T.; Neugebauer, G.; Oke, J.B.; Matthews, K.

1980-01-01

Low resolution spectra of a significant sample of quasars show that the Paschen α and Balmer line ratios do not agree with the radiative recombination case B result and vary widely within the quasars sampled. The range in Pα:Hβ ratios is a factor of approximately 6, while the range in Lyα:Hα ratios is a factor of approximately 5. For the Pα:Balmer series, the deviations from case B recombination are not consistent with reddening, but appear, within large dispersions, to be consistent with optical depth effects in the Balmer lines affecting the line ratios. The Lyα:Hα ratio is, however, correlated with the continuum spectral index, and can be explained as due to reddening affecting both the lines and continuum. Recent observational results based on a joint infrared/optical survey of the hydrogen line spectra of a significant number of the brightest low and high redshift quasars are summarised. This survey includes 12 quasars in the redshift range 0.07 1.5, where Hα and/or Hβ is redshifted into the 1.65μm or 2.2μm atmospheric windows. (Auth.)

Discovery of 21 New Changing-look AGNs: Study on Evolution of AGNs and AGN Host Galaxies

Science.gov (United States)

Yang, Qian; Wu, Xuebing; Fan, Xiaohui; Jiang, Linhua; McGreer, Ian; Shangguan, Jinyi; Yao, Su; Wang, Bingquan; Joshi, Ravi; Green, Richard F.; Wang, Feige; Feng, Xiaotong; Fu, Yuming; Yang, Jinyi; Liu, Yuanqi

2018-01-01

The rare case of changing-look (CL) AGNs, with the appearance or disappearance of broad Balmer emission lines within a few years, challenges our understanding of the AGN unified model. We present a sample of 21 new CL AGNs at 0.08 Survey Explorer (WISE), were detected in 15 CL AGNs during the transition. The optical and mid-infrared variability is not consistent with the scenario of variable obscuration in 10 CL AGNs at higher than 3σ confidence level. We confirm a bluer-when-brighter trend in the optical. However, the mid-infrared colors W1‑W2 become redder when the objects become brighter in the W1 band, possibly due to a stronger hot dust contribution in the W2 band when the AGN activity becomes stronger. The physical mechanism of type transition is important for understanding the evolution of AGNs. The rare CL AGNs provide exceptional cases for the black hole and host stellar velocity dispersion relation studies at higher redshift. The faint state spectrum can be used to obtain the host stellar velocity dispersion without contamination from AGN component, and the bright state spectrum can be used to calculate the black hole mass with broad Balmer emission lines. The images at the non-AGN phase of CL AGNs are useful for studies of AGN host galaxies avoiding contamination from the luminous central engines.

Discovery of flare activity on the dwarf M stars, GI 375 and GI 431

Energy Technology Data Exchange (ETDEWEB)

Doyle, J.G.; Mathioudakis, M.; Panagi, P.M.; Butler, C.J. (Armagh Observatory, (IE))

1990-12-01

Optical and infrared photometry plus spectroscopic data is present for two new flare stars, GI 375 and GI 431. Both of these stars have the hydrogen Balmer lines strongly in emission. Several flares were detected on GI 375 implying a high level of flare activity. The H{alpha} surface flux of 1.0 x 10{sup 6} erg cm{sup -2}s{sup -1} for both stars is similar to that of other active flare stars. Fluxes are given for several of the higher Balmer lines.

Enormous periodic doppler shifts in SS 433

International Nuclear Information System (INIS)

Margon, B.; Ford, H.C.; Grandi, S.A.; Stone, R.P.S.

1979-01-01

We have previously reported prominent ''moving' emission lines in the visible spectrum of Stephenson-Sanduleak 433, the optical counterpart of a variable radio and X-ray source. Further observations show that despite the implausible velocities and changes in velocities implied if the moving features are interpreted as Doppler-shifted Balmer lines, this explanation is indeed correct. Spectroscopy of SS 433 on 51 mights in 1978--1979 reveals that the unidentified features are two sets of Balmer and He I lines, one with large and changing redshift, and the other with large and changing blueshift. Combining our data with published earlier observations, we obtain Doppler shifts on 80 nights in the period 1978 June to 1979 June. These data indicate that the velocity variations are cyclical, repeating in both the blueshift and redshift systems with a period of 164 +- 3 days. The two systems have thus far been observed to reach maximum positive and negative radial velocities of +50,000 and -35,000 km s -1 , respectively, are always symmetric about redshift z=0.04, and follow roughly sinusoidal velocity curves. We discuss in addition a variety of interesting short-term spectroscopic details, including minor but highly significant deviations of the radial velocity from the sinusoid, and nightly line profile changes, sometimes appearing as mirror-image events in the redshift and blueshift systems. The behavior of SS 433 is unprecedented

Spectral Variations of T Tauri stars

Science.gov (United States)

Guenther, E.

1994-02-01

continuum is determined by subtracting a flux calibrated, scaled template spectrum from the flux calibrated, deredened T Taui star spectrum. The spectra of the veiling continuum exhibit a strong, variable Balmer Jump, but no Pashen Jump is seen. Hα is the only emission line in the spectrum of BM And, all other Balmer lines and the lines of He I appear in absorption, and are redshifted by at least 100 km/s. While the correlation between Hα and the veiling continuum is high, the correlation between all redshifted absorption lines and the veiling continuum is very low. From a comparison of observed and computed profiles of He I it is concluded that this line might form close to an accretion shock, and so should the higher Balmer. Since no redshifted absorption component is seen in Hα, the emission component must be optically thick, and should then be formed at a larger distance from the star than the redshifted absorption components, and hence the veiling continuum. The observations of BM And clearly show that the magnetic model is valid in this case, but the veiling continuum is not the emission of the accretion shock itself. DG Tau and DI Cep show the same kind of behavior. All emission lines have correlation factors between about 0.3 and 0.8. The highest correlations are found in the Balmer lines and low excitation Fe I and Fe II lines. There are no delay effects between the lines, all lines reach their maxima and minima at the same time. From the large Balmer decrement, and calculation of the Balmer lines and the veiling continuum in a simple slab model, it is concluded that the emitting region that is responsible for the emission lines and the veiling continuum has a temperature of 10000 K, and a density of 3**1018m-3 or less. In the slab geometry this corresponds to an emitting region which is at least 10000 km (≅ 0.01 R*) thick. It can thus be concluded that the region emitting the veiling continuum is relatively large and thin.

FFM Applications to Dense and Warm Hydrogen Plasma Study

International Nuclear Information System (INIS)

Calisti, A.; Talin, B.; Bureyeva, L. A.; Lisitsa, V. S.; Shuvaev, D.

2006-01-01

A study of hydrogen lines emitted in dense and low temperature plasmas is presented. A transition from impact to quasi-static broadening for electrons is analyzed with the help of the Frequency Fluctuation Model (FFM). Electron broadening of Balmer series lines is studied for different densities and temperatures spanning a wide domain from impact to quasi-static limit. It is shown that electronic broadening makes a transition from impact to quasi-static limit depending on plasma conditions and principal quantum number. Even for the Balmer alpha line, at a density equals 1018 cm-3 and a temperature equals 1 eV, this transition occurs both in the wings and the core of the line

Emission line galaxies and active galactic nuclei in WINGS clusters

Science.gov (United States)

Marziani, P.; D'Onofrio, M.; Bettoni, D.; Poggianti, B. M.; Moretti, A.; Fasano, G.; Fritz, J.; Cava, A.; Varela, J.; Omizzolo, A.

2017-03-01

We present the analysis of the emission line galaxies members of 46 low-redshift (0.04 employing diagnostic diagrams. We examined the emission line properties and frequencies of star-forming galaxies, transition objects, and active galactic nuclei (AGNs: LINERs and Seyferts), unclassified galaxies with emission lines, and quiescent galaxies with no detectable line emission. A deficit of emission line galaxies in the cluster environment is indicated by both a lower frequency, and a systematically lower Balmer emission line equivalent width and luminosity with respect to control samples; this implies a lower amount of ionized gas per unit mass and a lower star formation rate if the source is classified as Hii region. A sizable population of transition objects and of low-luminosity LINERs (≈ 10-20% of all emission line galaxies) are detected among WINGS cluster galaxies. These sources are a factor of ≈1.5 more frequent, or at least as frequent, as in control samples with respect to Hii sources. Transition objects and LINERs in clusters are most affected in terms ofline equivalent width by the environment and appear predominantly consistent with so-called retired galaxies. Shock heating can be a possible gas excitation mechanism that is able to account for observed line ratios. Specific to the cluster environment, we suggest interaction between atomic and molecular gas and the intracluster medium as a possible physical cause of line-emitting shocks. The data whose description is provided in Table B.1, and emission line catalog of the WINGS database are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/599/A83

A liquid lens switching-based motionless variable fiber-optic delay line

Science.gov (United States)

Khwaja, Tariq Shamim; Reza, Syed Azer; Sheikh, Mumtaz

2018-05-01

We present a Variable Fiber-Optic Delay Line (VFODL) module capable of imparting long variable delays by switching an input optical/RF signal between Single Mode Fiber (SMF) patch cords of different lengths through a pair of Electronically Controlled Tunable Lenses (ECTLs) resulting in a polarization-independent operation. Depending on intended application, the lengths of the SMFs can be chosen accordingly to achieve the desired VFODL operation dynamic range. If so desired, the state of the input signal polarization can be preserved with the use of commercially available polarization-independent ECTLs along with polarization-maintaining SMFs (PM-SMFs), resulting in an output polarization that is identical to the input. An ECTL-based design also improves power consumption and repeatability. The delay switching mechanism is electronically-controlled, involves no bulk moving parts, and can be fully-automated. The VFODL module is compact due to the use of small optical components and SMFs that can be packaged compactly.

Stellar model chromospheres. IV - The formation of the H-epsilon feature in the sun /G2 V/ and Arcturus /K2 III/

Science.gov (United States)

Ayres, T. R.; Linsky, J. L.

1975-01-01

The formation of the Balmer-series member H-epsilon in the near-red wing of the Ca II H line is discussed for two cases: the sun (H-epsilon absorption profile) and Arcturus (H-epsilon emission profile). It is shown that although the H-epsilon source functions in both stars are dominated by the Balmer-continuum radiation field through photoionizations, the line-formation problems in the two stars are quantitatively different, owing to a substantial difference in the relative importance of the stellar chromosphere temperature inversion as compared with the stellar photosphere.

Solar spectral irradiance variability of some chromospheric emission lines through the solar activity cycles 21-23

Directory of Open Access Journals (Sweden)

Göker Ü.D.

2017-01-01

Full Text Available A study of variations of solar spectral irradiance (SSI in the wave-length ranges 121.5 nm-300.5 nm for the period 1981-2009 is presented. We used various data for ultraviolet (UV spectral lines and international sunspot number (ISSN from interactive data centers such as SME (NSSDC, UARS (GDAAC, SORCE (LISIRD and SIDC, respectively. We reduced these data by using the MATLsoftware package. In this respect, we revealed negative correlations of intensities of UV (289.5 nm-300.5 nm spectral lines originating in the solar chromosphere with the ISSN index during the unusually prolonged minimum between the solar activity cycles (SACs 23 and 24. We also compared our results with the variations of solar activity indices obtained by the ground-based telescopes. Therefore, we found that plage regions decrease while facular areas are increasing in SAC 23. However, the decrease in plage regions is seen in small sunspot groups (SGs, contrary to this, these regions in large SGs are comparable to previous SACs or even larger as is also seen in facular areas. Nevertheless, negative correlations between ISSN and SSI data indicate that these variations are in close connection with the classes of sunspots/SGs, faculae and plage regions. Finally, we applied the time series analysis of spectral lines corresponding to the wavelengths 121.5 nm-300.5 nm and made comparisons with the ISSN data. We found an unexpected increase in the 298.5 nm line for the Fe II ion. The variability of Fe II ion 298.5 nm line is in close connection with the facular areas and plage regions, and the sizes of these solar surface indices play an important role for the SSI variability, as well. So, we compared the connection between the sizes of faculae and plage regions, sunspots/SGs, chemical elements and SSI variability. Our future work will be the theoretical study of this connection and developing of a corresponding model.

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

Science.gov (United States)

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.

High-resolution H -band Spectroscopy of Be Stars with SDSS-III/APOGEE. II. Line Profile and Radial Velocity Variability

Energy Technology Data Exchange (ETDEWEB)

Chojnowski, S. Drew; Holtzman, Jon A. [Apache Point Observatory and New Mexico State University, P.O. Box 59, Sunspot, NM, 88349-0059 (United States); Wisniewski, John P. [Department of Physics and Astronomy, The University of Oklahoma, 440 W. Brooks Street, Norman, OK 73019 (United States); Whelan, David G. [Department of Physics, Austin College, 900 N. Grand Avenue, Sherman, TX 75090 (United States); Labadie-Bartz, Jonathan; Pepper, Joshua [Department of Physics, Lehigh University, Bethlehem, PA 18015 (United States); Fernandes, Marcelo Borges [Observatório Nacional, Rua General José Cristino 77, 20921-400, São Cristovão, Rio de Janeiro (Brazil); Lin, Chien-Cheng [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road Shanghai 200030 (China); Majewski, Steven R. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Stringfellow, Guy S. [Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, Colorado 80309-0389 (United States); Mennickent, Ronald E.; Tang, Baitian [Departamento de Astronomía, Universidad de Concepción, Concepción (Chile); Roman-Lopes, Alexandre [Departamento de Física, Facultad de Ciencias, Universidad de La Serena, Cisternas 1200, La Serena (Chile); Hearty, Fred R. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Zasowski, Gail [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD, 21218 (United States)

2017-04-01

We report on the H -band spectral variability of classical Be stars observed over the course of the Apache Point Galactic Evolution Experiment (APOGEE), one of four subsurveys comprising SDSS-III. As described in the first paper of this series, the APOGEE B-type emission-line (ABE) star sample was culled from the large number of blue stars observed as telluric standards during APOGEE observations. In this paper, we explore the multi-epoch ABE sample, consisting of 1100 spectra for 213 stars. These “snapshots” of the circumstellar disk activity have revealed a wealth of temporal variability including, but not limited to, gradual disappearance of the line emission and vice versa over both short and long timescales. Other forms of variability include variation in emission strength, emission peak intensity ratios, and emission peak separations. We also analyze radial velocities (RVs) of the emission lines for a subsample of 162 stars with sufficiently strong features, and we discuss on a case-by-case basis whether the RV variability exhibited by some stars is caused by binary motion versus dynamical processes in the circumstellar disks. Ten systems are identified as convincing candidates for binary Be stars with as of yet undetected companions.

High-resolution H -band Spectroscopy of Be Stars with SDSS-III/APOGEE. II. Line Profile and Radial Velocity Variability

International Nuclear Information System (INIS)

Chojnowski, S. Drew; Holtzman, Jon A.; Wisniewski, John P.; Whelan, David G.; Labadie-Bartz, Jonathan; Pepper, Joshua; Fernandes, Marcelo Borges; Lin, Chien-Cheng; Majewski, Steven R.; Stringfellow, Guy S.; Mennickent, Ronald E.; Tang, Baitian; Roman-Lopes, Alexandre; Hearty, Fred R.; Zasowski, Gail

2017-01-01

We report on the H -band spectral variability of classical Be stars observed over the course of the Apache Point Galactic Evolution Experiment (APOGEE), one of four subsurveys comprising SDSS-III. As described in the first paper of this series, the APOGEE B-type emission-line (ABE) star sample was culled from the large number of blue stars observed as telluric standards during APOGEE observations. In this paper, we explore the multi-epoch ABE sample, consisting of 1100 spectra for 213 stars. These “snapshots” of the circumstellar disk activity have revealed a wealth of temporal variability including, but not limited to, gradual disappearance of the line emission and vice versa over both short and long timescales. Other forms of variability include variation in emission strength, emission peak intensity ratios, and emission peak separations. We also analyze radial velocities (RVs) of the emission lines for a subsample of 162 stars with sufficiently strong features, and we discuss on a case-by-case basis whether the RV variability exhibited by some stars is caused by binary motion versus dynamical processes in the circumstellar disks. Ten systems are identified as convincing candidates for binary Be stars with as of yet undetected companions.

BALANCE CAPACITY WITH VARIABILITY CAUSED BY HUMAN FACTOR: AN APPLICATION IN A LINE WITH MONTE CARLO SIMULATION

Directory of Open Access Journals (Sweden)

Augusto Sandes Mendes

2016-07-01

Full Text Available The variation in processing times due to the human factor between the working stations of a production line can generate queues resulting in a higher cost to the productive process. The objective of this study was to apply Monte Carlo simulation to balance the capacity of a production line with stations suffering variability in processing time due to the human factor. Simulations of the current situation of the production line were performed by comparing it with a proposal to align capacity with the production restriction in order to reduce inventories process while maintaining full capacity of the line. To develop the study, the selection involves the case of a company’s production line in the metal industry that produces machinery and products for metalworking area. The results allowed pointing suggestions for the company to reduce in-process inventory, keeping then total capacity of the line.

Dynamics of Line-Driven Winds from Disks in Cataclysmic Variables. I. Solution Topology and Wind Geometry

OpenAIRE

Feldmeier, Achim; Shlosman, Isaac

1999-01-01

We analyze the dynamics of 2-D stationary, line-driven winds from accretion disks in cataclysmic variable stars. The driving force is that of line radiation pressure, in the formalism developed by Castor, Abbott & Klein for O stars. Our main assumption is that wind helical streamlines lie on straight cones. We find that the Euler equation for the disk wind has two eigenvalues, the mass loss rate and the flow tilt angle with the disk. Both are calculated self-consistently. The wind is characte...

Detailed observations of NGC 4151 with IUE-III. Variability of the strong emission lines from 1978 February to 1980 May

International Nuclear Information System (INIS)

Ulrich, M.H.; Boksenberg, A.; Bromage, G.E.

1983-11-01

Observations of the variability of the three strong ultraviolet emission lines in the Seyfert galaxy NGC 4151 (CIV, CIII, and MgII) are used to study the structure of the broad line region and the nuclear energy source of this active galaxy. (author)

Electromagnetic analysis using transmission line variables

CERN Document Server

Weiner, Maurice

2010-01-01

This book employs a relatively new method for solving electromagnetic problems, one which makes use of a transmission line matrix (TLM). The propagation space is imagined to be filled with this matrix. The propagating fields and physical properties are then mapped onto the matrix. Mathematically, the procedures are identical with the traditional numerical methods; however, the interpretation and physical appeal of the transmission line matrix are far superior. Any change in the matrix has an immediate physical significance. What is also very important is that the matrix becomes a launching pad

Extinction of H II regions

International Nuclear Information System (INIS)

Israel, F.P.; Kennicutt, R.C.

1980-01-01

Visual extinction of H II regions in nine nearby galaxies as derived from the ratio of the radio continuum emission to H-alpha emission is systematically larger than visual extinction deduced from the Balmer lines alone, if one assumes a value Av/E(B-V) 3. An optically-limited sample of about 30 extragalactic H II regions has a mean extinction of 1.7 m in the visual while about 1.2 m is not seen in the reddening of the Balmer lines. Both reddening and extinction decreases with increasing galactic radius, at least for M33 and M101

Symbiotic variable V 1329 Cygni (=HBV 475) - a decade after its discovery

Energy Technology Data Exchange (ETDEWEB)

Grygar, J [Ceskoslovenska Akademie Ved, Ondrejov. Astronomicky Ustav; Hric, L; Chochol, D [Slovenska Akademia Vied, Skalnate Pleso (Czechoslovakia). Astronomicky Ustav; Mammano, A [Osservatorio Astrofisico, Asiago (Italy)

1979-01-01

The photometric and spectral history of the object since 1891 is briefly reviewed. The major outburst occurred in the year 1964 and in 1969 a strong ultraviolet and red continuum was detected along with the appearance of permitted and forbidden emission lines. After the outburst the object brightness slowly decreased but the cyclic variations with a period of 950sup(d) were clearly seen again. All photometric data thus support the suggestion that the system is an eclipsing binary. Spectroscopic data from the years 1971 to 1976 reveal periodic variations of the radial velocities of the emission lines with a period consistent with the photometric solution. The system apparently consists of a red giant of the spectral type M 5 II and of a very hot star; their masses are about 25Msub(Sun) and 1Msub(Sun), respectively. Line profiles of nebular as well as Balmer lines suggest the existence of ejected ''polar caps'' and an equatorial ring around the hot component, much like those in novae. The system can well be explained in terms of Bath's (1977) model. The hot component accretes the material from the giant via a strong stellar wind. Fluctuations in the optical brightness are probably caused by variations in the accretion rate on the hot star. The major outburst was caused by a shell flash which also ionized the expanding nebula surrounding the hot component.

Testing the white dwarf mass-radius relation and comparing optical and far-UV spectroscopic results with Gaia DR2, HST and FUSE

Science.gov (United States)

Joyce, S. R. G.; Barstow, M. A.; Casewell, S. L.; Burleigh, M. R.; Holberg, J. B.; Bond, H. E.

2018-05-01

Observational tests of the white dwarf mass-radius relationship have always been limited by the uncertainty in the available distance measurements. Most studies have focused on Balmer line spectroscopy because these spectra can be obtained from ground based observatories, while the Lyman lines are only accessible to space based UV telescopes. We present results using parallax data from Gaia DR2 combined with space based spectroscopy from HST and FUSE covering the Balmer and Lyman lines. We find that our sample supports the theoretical relation, although there is at least one star which is shown to be inconsistent. Comparison of results between Balmer and Lyman line spectra shows they are in agreement when the latest broadening tables are used. We also assess the factors which contribute to the error in the mass-radius calculations and confirm the findings of other studies which show that the spread in results for targets where multiple spectra are available is larger than the statistical error. The uncertainty in the spectroscopically derived log g parameter is now the main source of error rather than the parallax. Finally, we present new results for the radius and spectroscopic mass of Sirius B which agree with the dynamical mass and mass-radius relation within 1σ.

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

International Nuclear Information System (INIS)

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

2014-01-01

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 with levels of activity consistent with the Mg II fluxes and in agreement with that of normal quasars. These AGN may represent an extreme case of the Baldwin effect, with very low continuum and high equivalent width relative to typical quasars, but their ratio of broad Mg II to broad Balmer emission remains very unusual. They may also be representative of a class of AGN where the central engine is observed indirectly with scattered light. These galaxies represent a small fraction of the total population of luminous galaxies (≅ 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.

Transforming Image-Objects into Multiscale Fields: A GEOBIA Approach to Mitigate Urban Microclimatic Variability within H-Res Thermal Infrared Airborne Flight-Lines

Directory of Open Access Journals (Sweden)

Mir Mustafizur Rahman

2014-10-01

Full Text Available In an effort to minimize complex urban microclimatic variability within high-resolution (H-Res airborne thermal infrared (TIR flight-lines, we describe the Thermal Urban Road Normalization (TURN algorithm, which is based on the idea of pseudo invariant features. By assuming a homogeneous road temperature within a TIR scene, we hypothesize that any variation observed in road temperature is the effect of local microclimatic variability. To model microclimatic variability, we define a road-object class (Road, compute the within-Road temperature variability, sample it at different spatial intervals (i.e., 10, 20, 50, and 100 m then interpolate samples over each flight-line to create an object-weighted variable temperature field (a TURN-surface. The optimal TURN-surface is then subtracted from the original TIR image, essentially creating a microclimate-free scene. Results at different sampling intervals are assessed based on their: (i ability to visually and statistically reduce overall scene variability and (ii computation speed. TURN is evaluated on three non-adjacent TABI-1800 flight-lines (~182 km2 that were acquired in 2012 at night over The City of Calgary, Alberta, Canada. TURN also meets a recent GEOBIA (Geospatial Object Based Image Analysis challenge by incorporating existing GIS vector objects within the GEOBIA workflow, rather than relying exclusively on segmentation methods.

The peculiar balmer decrement of SN 2009ip: Constraints on circumstellar geometry

Energy Technology Data Exchange (ETDEWEB)

Levesque, Emily M.; Stringfellow, Guy S.; Bally, John; Keeney, Brian A. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado 389-UCB, Boulder, CO 80309 (United States); Ginsburg, Adam G., E-mail: Emily.Levesque@colorado.edu [European Southern Observatory, ESO Headquarters, Karl-Schwarzschild-Strasse 2, D-95748 Garching bei München (Germany)

2014-01-01

We present optical and near-IR spectroscopic observations of the luminous blue variable SN 2009ip during its remarkable photometric evolution of 2012. The spectra sample three key points in the SN 2009ip light curve, corresponding to its initial brightening in August (2012-A) and its dramatic rebrightening in early October (2012-B). Based on line fluxes and velocities measured in our spectra, we find a surprisingly low I(Hα)/I(Hβ) ratio (∼1.3-1.4) in the 2012-B spectra. Such a ratio implies either a rare Case B recombination scenario where Hα, but not Hβ, is optically thick, or an extremely high density for the circumstellar material of n{sub e} > 10{sup 13} cm{sup –3}. The Hα line intensity yields a minimum radiating surface area of ≳20,000 AU{sup 2} in Hα at the peak of SN 2009ip's photometric evolution. Combined with the nature of this object's spectral evolution in 2012, a high circumstellar density and large radiating surface area imply the presence of a thin disk geometry around the central star (and, consequently, a possible binary companion), suggesting that the observed 2012-B rebrightening of SN 2009ip can be attributed to the illumination of the disk's inner rim by fast-moving ejecta produced by the underlying events of 2012-A.

The origins of post-starburst galaxies at z < 0.05

Science.gov (United States)

Pawlik, M. M.; Taj Aldeen, L.; Wild, V.; Mendez-Abreu, J.; Lahén, N.; Johansson, P. H.; Jimenez, N.; Lucas, W.; Zheng, Y.; Walcher, C. J.; Rowlands, K.

2018-06-01

Post-starburst galaxies can be identified via the presence of prominent Hydrogen Balmer absorption lines in their spectra. We present a comprehensive study of the origin of strong Balmer lines in a volume-limited sample of 189 galaxies with 0.01 9.5 and projected axial ratio b/a > 0.32. We explore their structural properties, environments, emission lines, and star formation histories, and compare them to control samples of star-forming and quiescent galaxies, and simulated galaxy mergers. Excluding contaminants, in which the strong Balmer lines are most likely caused by dust-star geometry, we find evidence for three different pathways through the post-starburst phase, with most events occurring in intermediate-density environments: (1) a significant disruptive event, such as a gas-rich major merger, causing a starburst and growth of a spheroidal component, followed by quenching of the star formation (70 per cent of post-starburst galaxies at 9.510.5); (2) at 9.510.5, cyclic evolution of quiescent galaxies which gradually move towards the high-mass end of the red sequence through weak starbursts, possibly as a result of a merger with a smaller gas-rich companion (40 per cent). Our analysis suggests that active galactic nuclei (AGNs) are 'on' for 50 per cent of the duration of the post-starburst phase, meaning that traditional samples of post-starburst galaxies with strict emission-line cuts will be at least 50 per cent incomplete due to the exclusion of narrow-line AGNs.

THE MOSDEF SURVEY: DISSECTING THE STAR FORMATION RATE VERSUS STELLAR MASS RELATION USING Hα AND Hβ EMISSION LINES AT z ∼ 2

Energy Technology Data Exchange (ETDEWEB)

Shivaei, Irene; Reddy, Naveen A.; Siana, Brian; Mobasher, Bahram; Freeman, William R.; Groot, Laura de [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Shapley, Alice E.; Sanders, Ryan [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Kriek, Mariska; Price, Sedona H. [Astronomy Department, University of California, Berkeley, CA 94720 (United States); Coil, Alison L.; Azadi, Mojegan [Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, CA 92093 (United States)

2015-12-20

We present results on the star formation rate (SFR) versus stellar mass (M{sub *}) relation (i.e., the “main sequence”) among star-forming galaxies at 1.37 ≤ z ≤ 2.61 using the MOSFIRE Deep Evolution Field (MOSDEF) survey. Based on a sample of 261 galaxies with Hα and Hβ spectroscopy, we have estimated robust dust-corrected instantaneous SFRs over a large range in M{sub *} (∼10{sup 9.5}–10{sup 11.5} M{sub ⊙}). We find a correlation between log(SFR(Hα)) and log(M{sub *}) with a slope of 0.65 ± 0.08 (0.58 ± 0.10) at 1.4 < z < 2.6 (2.1 < z < 2.6). We find that different assumptions for the dust correction, such as using the color excess of the stellar continuum to correct the nebular lines, sample selection biases against red star-forming galaxies, and not accounting for Balmer absorption, can yield steeper slopes of the log(SFR)–log(M{sub *}) relation. Our sample is immune from these biases as it is rest-frame optically selected, Hα and Hβ are corrected for Balmer absorption, and the Hα luminosity is dust corrected using the nebular color excess computed from the Balmer decrement. The scatter of the log(SFR(Hα))–log(M{sub *}) relation, after accounting for the measurement uncertainties, is 0.31 dex at 2.1 < z < 2.6, which is 0.05 dex larger than the scatter in log(SFR(UV))–log(M{sub *}). Based on comparisons to a simulated SFR–M{sub *} relation with some intrinsic scatter, we argue that in the absence of direct measurements of galaxy-to-galaxy variations in the attenuation/extinction curves and the initial mass function, one cannot use the difference in the scatter of the SFR(Hα)– and SFR(UV)–M{sub *} relations to constrain the stochasticity of star formation in high-redshift galaxies.

Doppler-shifted neutral beam line shape and beam transmission

International Nuclear Information System (INIS)

Kamperschroer, J.H.; Grisham, L.R.; Kokatnur, N.; Lagin, L.J.; Newman, R.A.; O'Connor, T.E.; Stevenson, T.N.; von Halle, A.

1994-04-01

Analysis of Doppler-shifted Balmer-α line emission from the TFTR neutral beam injection systems has revealed that the line shape is well approximated by the sum of two Gaussians, or, alternatively, by a Lorentzian. For the sum of two Gaussians, the broad portion of the distribution contains 40% of the beam power and has a divergence five times that of the narrow part. Assuming a narrow 1/e- divergence of 1.3 degrees (based on fits to the beam shape on the calorimeter), the broad part has a divergence of 6.9 degrees. The entire line shape is also well approximated by a Lorentzian with a half-maximum divergence of 0.9 degrees. Up to now, fusion neutral beam modelers have assumed a single Gaussian velocity distribution, at the extraction plane, in each direction perpendicular to beam propagation. This predicts a beam transmission efficiency from the ion source to the calorimeter of 97%. Waterflow calorimetry data, however, yield a transmission efficiency of ∼75%, a value in rough agreement with predictions of the Gaussian or Lorentzian models presented here. The broad wing of the two Gaussian distribution also accurately predicts the loss in the neutralizer. An average angle of incidence for beam loss at the exit of the neutralizer is 2.2 degrees, rather than the 4.95 degrees subtended by the center of the ion source. This average angle of incidence, which is used in computing power densities on collimators, is shown to be a function of beam divergence

What makes red quasars red?. Observational evidence for dust extinction from line ratio analysis

Science.gov (United States)

Kim, Dohyeong; Im, Myungshin

2018-02-01

Red quasars are very red in the optical through near-infrared (NIR) wavelengths, which is possibly due to dust extinction in their host galaxies as expected in a scenario in which red quasars are an intermediate population between merger-driven star-forming galaxies and unobscured type 1 quasars. However, alternative mechanisms also exist to explain their red colors: (i) an intrinsically red continuum; (ii) an unusual high covering factor of the hot dust component, that is, CFHD = LHD/Lbol, where the LHD is the luminosity from the hot dust component and the Lbol is the bolometric luminosity; and (iii) a moderate viewing angle. In order to investigate why red quasars are red, we studied optical and NIR spectra of 20 red quasars at z 0.3 and 0.7, where the usage of the NIR spectra allowed us to look into red quasar properties in ways that are little affected by dust extinction. The Paschen to Balmer line ratios were derived for 13 red quasars and the values were found to be 10 times higher than unobscured type 1 quasars, suggesting a heavy dust extinction with AV > 2.5 mag. Furthermore, the Paschen to Balmer line ratios of red quasars are difficult to explain with plausible physical conditions without adopting the concept of the dust extinction. The CFHD of red quasars are similar to, or marginally higher than, those of unobscured type 1 quasars. The Eddington ratios, computed for 19 out of 20 red quasars, are higher than those of unobscured type 1 quasars (by factors of 3-5), and hence the moderate viewing angle scenario is disfavored. Consequently, these results strongly suggest the dust extinction that is connected to an enhanced nuclear activity as the origin of the red color of red quasars, which is consistent with the merger-driven quasar evolution scenario. Full Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/610/A31

How Sommerfeld extended Bohr's model of the atom (1913-1916)

Science.gov (United States)

Eckert, Michael

2014-04-01

Sommerfeld's extension of Bohr's atomic model was motivated by the quest for a theory of the Zeeman and Stark effects. The crucial idea was that a spectral line is made up of coinciding frequencies which are decomposed in an applied field. In October 1914 Johannes Stark had published the results of his experimental investigation on the splitting of spectral lines in hydrogen (Balmer lines) in electric fields, which showed that the frequency of each Balmer line becomes decomposed into a multiplet of frequencies. The number of lines in such a decomposition grows with the index of the line in the Balmer series. Sommerfeld concluded from this observation that the quantization in Bohr's model had to be altered in order to allow for such decompositions. He outlined this idea in a lecture in winter 1914/15, but did not publish it. The First World War further delayed its elaboration. When Bohr published new results in autumn 1915, Sommerfeld finally developed his theory in a provisional form in two memoirs which he presented in December 1915 and January 1916 to the Bavarian Academy of Science. In July 1916 he published the refined version in the Annalen der Physik. The focus here is on the preliminary Academy memoirs whose rudimentary form is better suited for a historical approach to Sommerfeld's atomic theory than the finished Annalen-paper. This introductory essay reconstructs the historical context (mainly based on Sommerfeld's correspondence). It will become clear that the extension of Bohr's model did not emerge in a singular stroke of genius but resulted from an evolving process.

COMPARISON OF ALPHA-ELEMENT-ENHANCED SIMPLE STELLAR POPULATION MODELS WITH MILKY WAY GLOBULAR CLUSTERS

International Nuclear Information System (INIS)

Lee, Hyun-chul; Worthey, Guy; Dotter, Aaron

2009-01-01

We present simple stellar population (SSP) models with scaled-solar and α-element-enhanced abundances. The SSP models are based on the Dartmouth Stellar Evolution Database, our library of synthetic stellar spectra, and a detailed systematic variation of horizontal-branch (HB) morphology with age and metallicity. In order to test the relative importance of a variety of SSP model ingredients, we compare our SSP models with integrated spectra of 41 Milky Way globular clusters (MWGCs) from Schiavon et al. Using the Mg b and Ca4227 indices, we confirm that Mg and Ca are enhanced by about +0.4 and +0.2 dex, respectively, in agreement with results from high-resolution spectra of individual stars in MWGCs. Balmer lines, particularly Hγ and Hδ, of MWGCs are reproduced by our α-enhanced SSP models not only because of the combination of isochrone and spectral effects but also because of our reasonable HB treatment. Moreover, it is shown that the Mg abundance significantly influences Balmer and iron line indices. Finally, the investigation of power-law initial mass function (IMF) variations suggests that an IMF much shallower than Salpeter is unrealistic because the Balmer lines are too strong on the metal-poor side to be compatible with observations.

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

Science.gov (United States)

Ponti, Gabriele

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

New value for the Rydberg constant by precision measurement of the hydrogen Balmer-β transition

International Nuclear Information System (INIS)

Zhao, P.

1986-01-01

The Rydberg constant R is determined to a very high accuracy of 3 parts in 10 10 by a direct comparison of the four hydrogen and deuterium Balmer-β transitions with a standard laser from the National Bureau of Standards. This experiment is now the most precise measurement for R and approaches the limits of accuracy for wavelength or frequency measurements in the visible region. The result is R = 109 737.315 73 (3) cm -1 with the definition of the meter: c = 299 792 458 m/sec. The experiment also yields the following results: the fine-structure splittings 4P/sub 1/2/ ↔ 4P/sub 3/2 in H: 1370.9 (3) MHz and in D: 1371.8(3) MHZ. The isotope shifts between H and D in the transitions 2S/sub 1/2/ ↔ 4P/sub 1/2/: 167 752.4(3) MHz and 2S/sub 1/2/ ↔ 4P/sub 3/2/ : 167 753.3 (3) MHz. The experiment utilizes atomic beam laser spectroscopy. A beam of atomic hydrogen (or deuterium) is excited by electron bombardment to the metastable 2S/sub 1/2/ state and is detected by a secondary electron emission detector. A chopped cw dye laser beam crosses the atomic beam at an angle of 90 0 to eliminate Doppler broadening. The metastables are quenched by laser excitation to 4P/sub 1/2/ or 4P/sub 3/2/ states. The signal is monitored by a lock-in amplifier with the chopper as reference

RAPID INFRARED VARIABILITY OF THREE RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES: A VIEW FROM THE WIDE-FIELD INFRARED SURVEY EXPLORER

Energy Technology Data Exchange (ETDEWEB)

Jiang Ning; Zhou Hongyan; Wang Tinggui; Dong Xiaobo; Jiang Peng [Key Laboratory for Research in Galaxies and Cosmology, University of Science and Technology of China, Chinese Academy of Science, Hefei, Anhui 230026 (China); Ho, Luis C. [The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Yuan Weimin [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Ji Tuo; Tian Qiguo, E-mail: jnac@mail.ustc.edu.cn [Polar Research Institute of China, 451 Jinqiao Road, Pudong, Shanghai 200136 (China)

2012-11-10

Using newly released data from the Wide-field Infrared Survey Explorer, we report the discovery of rapid infrared variability in three radio-loud narrow-line Seyfert 1 galaxies (NLS1s) selected from the 23 sources in the sample of Yuan et al. J0849+5108 and J0948+0022 clearly show intraday variability, while J1505+0326 has a longer measurable timescale within 180 days. Their variability amplitudes, corrected for measurement errors, are {approx}0.1-0.2 mag. The detection of intraday variability restricts the size of the infrared-emitting region to {approx}10{sup -3} pc, significantly smaller than the scale of the torus but consistent with the base of a jet. The three variable sources are exceptionally radio-loud, have the highest radio brightness temperature among the whole sample, and all show detected {gamma}-ray emission in Fermi/LAT observations. Their spectral energy distributions resemble those of low-energy-peaked blazars, with a synchrotron peak around infrared wavelengths. This result strongly confirms the view that at least some radio-loud NLS1s are blazars with a relativistic jet close to our line of sight. The beamed synchrotron emission from the jet contributes significantly to and probably dominates the spectra in the infrared and even optical bands.

An interpretation of hydrogen and helium line spectra of the loop prominence observed on November 3, 1973

International Nuclear Information System (INIS)

Kureizumi, Takeshi; Kubota, Jun; Kawaguchi, Ichiro; Tamenaga, Tatsuo; Maeda, Koichiro.

1977-01-01

The H sub(I), He sub(I), and He sub(II) emission lines of the loop prominence observed on November 3, 1973 in the rapidly developing phase are analyzed. The difference in widths of these lines suggests they do not originate in the same volume. The estimated T sub(e) (8000-9000 K) and n sub(e) (-- 2 x 10 12 cm -3 ) in the loop from the Balmer lines do not change appreciably with time everywhere in the loop during our observation (00 sup(h)40 sup(m)-01 sup(h)10 sup(m)UT). The degree of ionization of hydrogen is estimated to be in the range of 0.8 to 1.0. The ionizing mechanisms may be attributed to the UV radiation (lambda<=912A) from the underlying flare region. Local thermodynamic equilibrium (LTE) is approximately established in the excited levels of He sub(I), but the singlet levels are somewhat overpopulated. The UV radiation field (lambda<=504A) from the surrounding coronal condensation is estimated from microwave and X-ray flux measurements of S sub(OLRAD)9. The ionization of He sub(I) (ionization degree 0.1-0.2) is mainly controlled by UV radiation from the coronal condensation. An adequate thread structure model of the loop prominence is suggested. (auth.)

Age-related variability of some characters of karyotype instability in the mouse line CC57W/Mv

International Nuclear Information System (INIS)

Glazko, T.T.; Safonova, N.A.; Kovaleva, O.A.; Stolina, M.P.; Solomko, A.P.; Malyuta, S.S.; Glazko, V.I.; AN Ukrainskoj SSR, Kiev

1995-01-01

The investigations of relations between cytogenetical variability in cells of bone marrow of the mouse line CC57W/Mv and factors of age and radioactivity pollution (the specific vivarium in the 30-km Chernobyl zone) were carried out. The karyotype instability on some characters were similarly between young mice in the Chernobyl zone and old mice under control conditions. The old Chernobyl mice differentiated from old control ones by a low frequency of some cytogenetic anomalies and higher values of the mitotic index. The contribution of the intensity of cell division into observed variabilities of cytogenetic character between different mouse groups was discussed

Variability of the inclination of anatomic horizontal reference planes of the craniofacial complex in relation to the true horizontal line in orthognathic patients.

Science.gov (United States)

Zebeib, Ameen M; Naini, Farhad B

2014-12-01

The purpose of this study was to assess the reliability of the Frankfort horizontal (FH), sella-nasion horizontal, and optic planes in terms of their variabilities in relation to a true horizontal line in orthognathic surgery patients. Thirty-six consecutive presurgical orthognathic patients (13 male, 23 female; age range, 16-35 years; 30 white, 6 African Caribbean) had lateral cephalometric radiographs taken in natural head position, with a plumb line orientating the true vertical line, and the true horizontal line perpendicular to the true vertical. The inclinations of the anatomic reference planes were compared with the true horizontal. The FH plane was found to be on average closest to the true horizontal, with a mean of -1.6° (SD, 3.4°), whereas the sella-nasion horizontal and the optic plane had means of 2.1° (SD, 5.1°) and 3.2° (SD, 4.7°), respectively. The FH showed the least variability of the 3 anatomic planes. The ranges of variability were high for all anatomic planes: -8° to 8° for the FH, -8° to 15° for the sella-nasion horizontal, and -6° to 13° for the optic plane. No significant differences were found in relation to patients' sex, skeletal patterns, or ethnic backgrounds. The clinically significant variability in the inclinations of anatomic reference planes in relation to the true horizontal plane makes their use unreliable in orthognathic patients. Copyright © 2014 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Time dependence of the UV resonance lines in the cataclysmic variables SU UMa, RX And and 0623+71

International Nuclear Information System (INIS)

Woods, J.A.; Drew, J.E.; Verbunt, Frank

1990-01-01

We present IUE observations of the dwarf novae SU UMa and RX And, and of the nova-like variable 0623 + 71. At the time of observation, SU UMa and RX And were in outburst. All three systems show variability in the wind-formed UV resonance lines of N v λ 1240, Si IV λ 1397 and C IV λ 1549 on timescale of hours. The amplitude of variation is smallest in RX And and largest in 0623 + 71. There is evidence that the variations observed in SU UMa's UV spectrum repeat on the orbital period. Our observations of SU UMa also reveal variability in the continuum flux during the decline from outburst maximum that is much more marked in the UV than at optical wavelengths. (author)

Nonlinear Color–Metallicity Relations of Globular Clusters. VII. Nonlinear Absorption-line Index versus Metallicity Relations and Bimodal Index Distributions of NGC 5128 Globular Clusters

Energy Technology Data Exchange (ETDEWEB)

Kim, Sooyoung; Yoon, Suk-Jin, E-mail: sjyoon0691@yonsei.ac.kr [Department of Astronomy and Center for Galaxy Evolution Research, Yonsei University, Seoul 120-749 (Korea, Republic of)

2017-07-01

Spectroscopy on the globular cluster (GC) system of NGC 5128 revealed bimodality in absorption-line index distributions of its old GCs. GC division is a widely observed and studied phenomenon whose interpretation has depicted host galaxy formation and evolution such that it harbors two distinct metallicity groups. Such a conventional view of GC bimodality has mainly been based on photometry. The recent GC photometric data, however, presented an alternative perspective in which the nonlinear metallicity-to-color transformation is responsible for color bimodality of GC systems. Here we apply the same line of analysis to the spectral indices and examine the absorption-line index versus metallicity relations for the NGC 5128 GC system. NGC 5128 GCs display nonlinearity in the metallicity-index planes, most prominently for the Balmer lines and by a non-negligible degree for the metallicity-sensitive magnesium line. We demonstrate that the observed spectroscopic division of NGC 5128 GCs can be caused by the nonlinear nature of the metallicity-to-index conversions and thus one does not need to resort to two separate GC subgroups. Our analysis incorporating this nonlinearity provides a new perspective on the structure of NGC 5128's GC system, and a further piece to the global picture of the formation of GC systems and their host galaxies.

On the nature of WX Ceti

International Nuclear Information System (INIS)

Downes, R.A.; Margon, B.

1981-01-01

WX Ceti is a large amplitude (8 mag) variable which has undergone at least four outbursts during this century. Bailey has suggested that this object may be related to WZ Sge, and is part of a small but distinct subgroup of dwarf novae. Spectroscopy of WX Cet has been obtained at minimum light, revealing extremely strong, broad Balmer emission, but no He II lambda 4686. The spectrum indeed resembles WZ Sge at minimum, although it lacks the broad Balmer absorptions of the latter object. The data confirm the cataclysmic variable nature of WX Cet, and indicate that the proposed association with WZ Sge is plausible. (author)

Characterisation of detached plasmas on the MAST tokamak

Energy Technology Data Exchange (ETDEWEB)

Harrison, J.R., E-mail: james.harrison@ccfe.ac.uk [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon, OX14 3DB (United Kingdom); Department of Physics, University of York, Heslington, York, YO10 5DD (United Kingdom); Lisgo, S.W. [ITER Organization, Route de Vinon-sur-Verdon, St.Paul-lez-Durance, Cedex (France); Gibson, K.J. [Department of Physics, University of York, Heslington, York, YO10 5DD (United Kingdom); Tamain, P. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Dowling, J. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon, OX14 3DB (United Kingdom)

2011-08-01

Divertor detachment is an attractive operating regime for the next generation of tokamak devices, as it offers a means of mitigating the steady-state heat flux to plasma facing components. In order to clarify the dominant physical mechanisms that govern detachment, high quality data from several diagnostics are required to constrain theoretical models. To that end, high spatial ({approx}3 mm) and temporal (5 kHz) resolution measurements have been made of the intensity of deuterium Balmer and carbon emission lines during the onset and evolution of detachment of the lower inner strike point in MAST L-mode discharges. Furthermore, spatially-resolved measurements of the shapes and intensities of high-n Balmer lines have been recorded to infer plasma conditions during the detached phase.

Q2122-444: A NAKED ACTIVE GALACTIC NUCLEUS FULLY DRESSED

International Nuclear Information System (INIS)

Gliozzi, M.; Satyapal, S.; Panessa, F.; Franca, F. La; Saviane, I.; Monaco, L.; Foschini, L.; Kedziora-Chudczer, L.; Sambruna, R. M.

2010-01-01

Based on previous spectral and temporal optical studies, Q2122-444 has been classified as a naked active galactic nucleus (AGN) or true type 2 AGN, that is, an AGN that genuinely lacks a broad-line region (BLR). Its optical spectrum seemed to possess only narrow forbidden emission lines that are typical of type 2 (obscured) AGNs, but the long-term optical light curve, obtained from a monitoring campaign over more than two decades, showed strong variability, apparently ruling out the presence of heavy obscuration. Here we present the results from a ∼40 ks XMM-Newton observation of Q2122-444 carried out to shed light on the energetics of this enigmatic AGN. The X-ray analysis was complemented with Australia Telescope Compact Array radio data to assess the possible presence of a jet, and with new NTT/EFOSC2 optical spectroscopic data to verify the actual absence of a BLR. The higher-quality optical data revealed the presence of strong and broad Balmer lines that are at odds with the previous spectral classification of this AGN. The lack of detection of radio emission rules out the presence of a jet. The X-ray data combined with simultaneous UV observations carried out by the Optical Monitor (OM) aboard XMM-Newton confirm that Q2122-444 is a typical type 1 AGN without any significant intrinsic absorption. New estimates of the black hole mass independently obtained from the broad Balmer lines and from a new scaling technique based on X-ray spectral data suggest that Q2122-444 is accreting at a relatively high rate in Eddington units.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

2016-01-27

Jan 27, 2016 ... ... calculations of hydrogen Lyman and Balmer lines, in the framework of magnetic fusion research. The role of the Zeeman effect, fine structure and the plasma's non-homogeneity along the line-of-sight are investigated. Under specific conditions, our results are applicable to DA white dwarf atmospheres.

INTRINSIC FACTORS AND FIRM FINANCIAL ANALYSIS WITH TRIPPLE BOTTOM LINES AS INTERVENING VARIABLE AGAINST FIRM VALUE Empirical Studies on Property and Real Estate Companies Year 2010-2013

Directory of Open Access Journals (Sweden)

Mia Andika Sari

2016-09-01

Full Text Available This research conducted to examine the influence of intrinsic factors which being peroxided with Capital Structure, Firm Size, Firm Age and Financial factors that being peroxided with liquidity, profitability also with another activities using triple bottom lines as Intervening Variable against Firm Value of Property Industries. The data that being used in this study were obtained from published financial statements during the period 2010 to 2013, as well as annual reports that can be accessed through the IDX website. Data analysis technique used in this study is a regression with panel data and path analysis. The results of this research showed that intrinsic factors and financial variables have a significant influence on the firm value, as well as intrinsic factors and financial variables have a significant influence on the triple bottom lines. From the results of path analysis demonstrated that the indirect effect using the triple bottom lines as a intervening variable was greater than the direct effect.

Spectroscopic Study of the Polar BS Tri

Science.gov (United States)

Borisov, N. V.; Gabdeev, M. M.; Shimansky, V. V.; Katysheva, N. A.; Shugarov, S. Yu.

2015-11-01

We have analyzed the spectra of the cataclysmic variable BS Tri taken in September 2011 and August 2012 with the 6-m BTA SAO RAS telescope. The object's spectra exhibit a flat continuum with superimposed strong hydrogen Balmer, neutral and ionized helium emission lines. Our analysis of the line profiles has shown that they consist of several components that are formed in the accretion structure and on the irradiated red dwarf surface. The measured radial velocities of one of the components of the line forming in a spot on the red dwarf surface have allowed the parameters of the system to be estimated: M 1 = 0.75 ± 0.02 M ⊙, M 2 = 0.16 ± 0.01 M ⊙, q = 0.21 ± 0.02, and R L2 = 0.18 ± 0.02 R ⊙. The Doppler maps constructed from the emission lines show no disk accretion, defining the system as a polar.

Radiative and three-body recombination in the Alcator C-Mod divertor

International Nuclear Information System (INIS)

Lumma, D.; Terry, J.L.; Lipschultz, B.

1997-01-01

Significant recombination of the majority ion species has been observed in the divertor region of Alcator C-Mod [I. H. Hutchinson et al., Phys. Plasmas 1, 1511 (1994)] under detached conditions. This determination is made by analysis of the visible spectrum from the divertor, in particular the Balmer series line emission and the observed recombination continuum, including an apparent recombination edge at ∼375 nm. The analysis shows that the electron temperature in the recombining plasma is 0.8 endash 1.5 eV. The measured volume recombination rate is comparable to the rate of ion collection at the divertor plates. The dominant recombination mechanism is three-body recombination into excited states (e+e+D + Right-arrow D 0 +e), although radiative recombination (e+D + Right-arrow D 0 +hν) contributes ∼5% to the total rate. Analysis of the Balmer series line intensities (from n upper =3 through 10) shows that the upper levels of these transitions are populated primarily by recombination. Thus the brightnesses of the Balmer series (and Lyman series) are directly related to the recombination rate. copyright 1997 American Institute of Physics

Kinetics of hydrogen in chromospheres of red dwarfs

International Nuclear Information System (INIS)

Bruevich, E.A.; Katsova, M.M.; Livshits, M.A.; AN SSSR, Moscow

1990-01-01

A method is suggested and solution is conducted of the stationary equations for an 8-level hydrogen atom with an approximate account for lines radiative transfer in an optically thick layer. Ionization and excitation of hydrogen atoms are caused by electron collisions; the influence of photospheric radiation was neglected. The medium stays motionless, and the photon escape from the layer is connected with gradual diffusion in frequency during multiple scatterings. Mean over the layer probabilities of photon escape are introduced into the stationary equations. They are determined for a finite-thickness layer with an uniform distribution of primary photon sources and with an absorption coefficient accounting for Stark and Doppler effects. As an example of application of the calculations, an interpretation is presented of the data on the Balmer decrement in the maximum of the stellar flare of YZ CMi on March 4, 1985. It is shown that the transition from a steep Balmer decrement to a mildly sloping one is due to a decrease of the photon escape probability in the higher members of Balmer series, i.e. the lines later than H γ

Spectral and photometric studies of the polar USNO-A2.0 0825-18396733

Science.gov (United States)

Gabdeev, M. M.; Borisov, N. V.; Shimansky, V. V.; Spiridonova, O. I.

2015-03-01

Results of photometric and spectral studies of the new magnetic cataclysmic variable (polar) USNO-A2.0 0825-18396733 are presented. Photometric data in the B, V, and R c filters show that this object exhibits a red excess of R c - V = 1 m . A red continuum with superposed strong single-peaked Balmer emission lines and HeII λ4686 Å emission, weak lines of neutral helium, and lines of heavy elements are observed in the object's spectra. Doppler maps constructed using the hydrogen and ionized-helium lines indicate that these lines form near the inner Lagrangian point, and that their formation is associated with an accretion stream. The spectra and radial-velocity curves indicate the eclipse of the white dwarf in the system to be partial. Radial-velocity curves derived for emission lines are used to estimate the component masses. The mass of the white dwarf is estimated to be 0.71-0.78 M ⊙, and the mass of the red dwarf to be 0.18-0.20 M ⊙.

VARIABILITY OF THE SiO THERMAL LINE EMISSION TOWARD THE YOUNG L1448-mm OUTFLOW

International Nuclear Information System (INIS)

Jimenez-Serra, I.; MartIn-Pintado, J.; RodrIguez-Franco, A.; Winters, J.-M.; Caselli, P.

2011-01-01

The detection of narrow SiO thermal emission toward young outflows has been proposed to be a signature of the magnetic precursor of C-shocks. Recent modeling of the SiO emission across C-shocks predicts variations in the SiO line intensity and line shape at the precursor and intermediate-velocity regimes in only a few years. We present high angular resolution (3.''8 x 3.''3) images of the thermal SiO J = 2→1 emission toward the L1448-mm outflow in two epochs (2004 November-2005 February, 2009 March-April). Several SiO condensations have appeared at intermediate velocities (20-50 km s -1 ) toward the redshifted lobe of the outflow since 2005. Toward one of the condensations (clump D), systematic differences of the dirty beams between 2005 and 2009 could be responsible for the SiO variability. At higher velocities (50-80 km s -1 ), SiO could also have experienced changes in its intensity. We propose that the SiO variability toward L1448-mm is due to a real SiO enhancement by young C-shocks at the internal working surface between the jet and the ambient gas. For the precursor regime (5.2-9.2 km s -1 ), several narrow and faint SiO components are detected. The narrow SiO components tend to be compact, transient and show elongated (bow-shock) morphologies perpendicular to the jet. We speculate that these features are associated with the precursor of C-shocks appearing at the interface of the new SiO components seen at intermediate velocities.

The variable cyclotron line of GX 301-2

Energy Technology Data Exchange (ETDEWEB)

Kreykenbohm, I.; Wilms, J.; Coburn, W.; Kuster, M.; Rothschild, R.E.; Heindl, W.A.; Kretschmar, P.; Staubert, R

2004-06-01

We present a 200 ksec observation of the High Mass X-ray Binary GX 301-2 taken in 2000 November with the Rossi X-ray Timing Explorer during the pre-periastron flare and the actual periastron passage of the neutron star. To model the spectrum we use a power law with the Fermi Dirac cutoff and a cyclotron line at higher energies plus either a reflection component or a heavily absorbed partial covering component. Although completely different, both models describe the data equally well. Phase resolved spectra show that the energy and the depth of the cyclotron resonant scattering feature vary strongly with pulse phase: It is deepest in the fall of the main pulse, the rise of the secondary pulse, and the pulse minimum in-between with {tau}{sub C}{approx}0.3. In the other phase bins the line is much less deep with {tau}{sub C}{approx}0.1. The energy of the line correlates strongly with its depth and varies by 25 % from 30.1 keV in the fall of the secondary pulse to 37.9 keV in the fall of the main pulse.

Precision Measurement of the Energies and Line Shapes of Antiprotonic Lyman and Balmer Transitions From Hydrogen and Helium Isotopes

CERN Multimedia

2002-01-01

% PS207 \\\\ \\\\ For the study of the antiproton-proton and antiproton-nuclear spin-spin and spin-orbital interaction at threshold a high resolution measurement is proposed of the line shapes and energy shifts of antiprotonic K$\\alpha$ and L$\\alpha$ transitions of hydrogen and helium isotopes. The intense LEAR beam, stopped in the cyclotron trap at low gas pressure, provides a unique~X-ray~source with sufficient brightness. Charge coupled devices with their excellent background rejection and energy resolution allow a precise determination of the strong shifts and widths of the 1s hyperfine states of protonium, in addition the detection of the $\\bar{p}$D K$\\alpha$ transition should be possible. A focussing crystal spectrometer with a resolution $\\Delta$E/E of about l0$ ^- ^{4} $, which is superior in the accuracy of the energy determination by two orders of magnitude as compared to the present detection methods, will be used to measure the energies of the L$\\alpha$ transitions. This permits a first direct measure...

Kinetic energy measurement of hydrogen in LHD peripheral plasma with a multi-wavelength-range fine-resolution spectrometer

International Nuclear Information System (INIS)

Fujii, Keisuke; Mizushiri, Keisuke; Nishioka, Tomomi; Shikama, Taiichi; Iwamae, Atsushi; Goto, Motoshi; Morita, Shigeru; Hasuo, Masahiro

2010-01-01

We have simultaneously measured high resolution emission spectra of the hydrogen atomic Balmer-α, -β, -γ lines and molecular Fulcher-α band for a LHD peripheral plasma generated under a central magnetic field strength of 0.4 T. It is found that the velocity distributions of excited atoms calculated from the Balmer-α, -β, and -γ line shapes show similar profiles to each other. The translational kinetic energy corresponding to the average velocity is about 13 eV, which is about 300 times larger than the rotational energy of hydrogen molecules estimated from the line intensities in the Fulcher-α band. The velocity distributions differ from Maxwellian and have a high velocity tail over 1x10 5 m/s. A correlation between the high velocity tail and the electron temperature and density is seen and suggesting the excited atoms having such high velocities to be generated by the charge exchange collisions from high velocity protons in the peripheral region.

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Indian Academy of Sciences (India)

effects for Lyman and Balmer lines with a 'moderate' principal quantum number ... a non-Hermitian part accounting for natural broadening) and the Zeeman effect .... The authors would like to acknowledge the financial support from the Agence.

STRONG UV AND X-RAY VARIABILITY OF THE NARROW LINE SEYFERT 1 GALAXY WPVS 007-ON THE NATURE OF THE X-RAY LOW STATE

Energy Technology Data Exchange (ETDEWEB)

Grupe, Dirk; Barlow, Brad N. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Komossa, S. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Scharwaechter, Julia [Research School of Astronomy and Astrophysics, Australian National University, Mount Stromlo Observatory, Cotter Road, Weston Creek, ACT 2611 (Australia); Dietrich, Matthias [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Leighly, Karen M.; Lucy, Adrian, E-mail: dxg35@psu.edu, E-mail: julia.scharwaechter@obspm.fr, E-mail: leighly@nhn.ou.edu [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 West Brooks Street, Norman, OK 73019 (United States)

2013-10-01

We report on multi-wavelength observations of the X-ray transient Narrow Line Seyfert 1 (NLS1) galaxy WPVS 007. The galaxy was monitored with Swift between 2005 October and 2013 July, after it had previously undergone a dramatic drop in its X-ray flux. For the first time, we are able to repeatedly detect this NLS1 in X-rays again. This increased number of detections in the last couple of years may suggest that the strong absorber that has been found in this active galactic nucleus (AGN) is starting to become leaky and may eventually disappear. The X-ray spectra obtained for WPVS 007 are all consistent with a partial covering absorber model. A spectrum based on the data during the extreme low X-ray flux states shows that the absorption column density is of the order of 4 Multiplication-Sign 10{sup 23} cm{sup -2} with a covering fraction of 95%. WPVS 007 also displays one of the strongest UV variabilities seen in NLS1s. The UV continuum variability anti-correlates with the optical/UV slope {alpha}{sub UV}, which suggests that the variability may be primarily due to reddening. The UV variability timescales are consistent with moving dust ''clouds'' located beyond the dust sublimation radius of R{sub sub} Almost-Equal-To 20 lt-days. We present for the first time near-infrared JHK data of WPVS 007, which reveal a rich emission-line spectrum. Recent optical spectroscopy does not indicate significant variability in the broad permitted and Fe II emission lines, implying that the ionizing continuum seen by those gas clouds has not significantly changed over the last decades. All X-ray and UV observations are consistent with a scenario in which an evolving broad absorption line (BAL) flow obscures the continuum emission. As such, WPVS 007 is an important target for our understanding of BAL flows in low-mass AGNs.

Spatially Resolved HST Grism Spectroscopy of a Lensed Emission Line Galaxy at z ~ 1

Science.gov (United States)

Frye, Brenda L.; Hurley, Mairead; Bowen, David V.; Meurer, Gerhardt; Sharon, Keren; Straughn, Amber; Coe, Dan; Broadhurst, Tom; Guhathakurta, Puragra

2012-07-01

We take advantage of gravitational lensing amplification by A1689 (z = 0.187) to undertake the first space-based census of emission line galaxies (ELGs) in the field of a massive lensing cluster. Forty-three ELGs are identified to a flux of i 775 = 27.3 via slitless grism spectroscopy. One ELG (at z = 0.7895) is very bright owing to lensing magnification by a factor of ≈4.5. Several Balmer emission lines (ELs) detected from ground-based follow-up spectroscopy signal the onset of a major starburst for this low-mass galaxy (M * ≈ 2 × 109 M ⊙) with a high specific star formation rate (≈20 Gyr-1). From the blue ELs we measure a gas-phase oxygen abundance consistent with solar (12+log(O/H) = 8.8 ± 0.2). We break the continuous line-emitting region of this giant arc into seven ~1 kpc bins (intrinsic size) and measure a variety of metallicity-dependent line ratios. A weak trend of increasing metal fraction is seen toward the dynamical center of the galaxy. Interestingly, the metal line ratios in a region offset from the center by ~1 kpc have a placement on the blue H II region excitation diagram with f ([O III])/f (Hβ) and f ([Ne III])/f (Hβ) that can be fitted by an active galactic nucleus (AGN). This asymmetrical AGN-like behavior is interpreted as a product of shocks in the direction of the galaxy's extended tail, possibly instigated by a recent galaxy interaction. Based, in part, on data obtained with the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W. M. Keck Foundation.

Spectrophotometry of the Seyfert galaxy NGC 4593

International Nuclear Information System (INIS)

MacAlpine, G.M.; Williams, G.A.; Lewis, D.W.

1979-01-01

Spectrophotometry of the bright class 1 Seyfert galaxy NGC 4593 is presented. The emission-line characteristics are briefly discussed and compared with those of other Seyfert galaxies. The measured hydrogen Balmer-line ratios are reasonably consistent with expected recombination values, and the emission intensities of Fe II, He I 5876, and forbidden O III 4363 relative to other lines are stronger than average in NGC 4593

High resolution measurements and modeling of auroral hydrogen emission line profiles

Directory of Open Access Journals (Sweden)

B. S. Lanchester

Full Text Available Measurements in the visible wavelength range at high spectral resolution (1.3 Å have been made at Longyearbyen, Svalbard (15.8 E,78.2 N during an interval of intense proton precipitation. The shape and Doppler shift of hydrogen Balmer beta line profiles have been compared with model line profiles, using as input ion energy spectra from almost coincident passes of the FAST and DMSP spacecraft. The comparison shows that the simulation contains the important physical processes that produce the profiles, and confirms that measured changes in the shape and peak wave-length of the hydrogen profiles are the result of changing energy input. This combination of high resolution measurements with modeling provides a method of estimating the incoming energy and changes in flux of precipitating protons over Svalbard, for given energy and pitch-angle distributions. Whereas for electron precipitation, information on the incident particles is derived from brightness and brightness ratios which require at least two spectral windows, for proton precipitation the Doppler profile of resulting hydrogen emission is directly related to the energy and energy flux of the incident energetic protons and can be used to gather information about the source region. As well as the expected Doppler shift to shorter wavelengths, the measured profiles have a significant red-shifted component, the result of upward flowing emitting hydrogen atoms.

Key words. Ionosphere (auroral ionosphere; particle precipitation – Magnetospheric physics (auroral phenomena

High resolution measurements and modeling of auroral hydrogen emission line profiles

Directory of Open Access Journals (Sweden)

B. S. Lanchester

2003-07-01

Full Text Available Measurements in the visible wavelength range at high spectral resolution (1.3 Å have been made at Longyearbyen, Svalbard (15.8 E,78.2 N during an interval of intense proton precipitation. The shape and Doppler shift of hydrogen Balmer beta line profiles have been compared with model line profiles, using as input ion energy spectra from almost coincident passes of the FAST and DMSP spacecraft. The comparison shows that the simulation contains the important physical processes that produce the profiles, and confirms that measured changes in the shape and peak wave-length of the hydrogen profiles are the result of changing energy input. This combination of high resolution measurements with modeling provides a method of estimating the incoming energy and changes in flux of precipitating protons over Svalbard, for given energy and pitch-angle distributions. Whereas for electron precipitation, information on the incident particles is derived from brightness and brightness ratios which require at least two spectral windows, for proton precipitation the Doppler profile of resulting hydrogen emission is directly related to the energy and energy flux of the incident energetic protons and can be used to gather information about the source region. As well as the expected Doppler shift to shorter wavelengths, the measured profiles have a significant red-shifted component, the result of upward flowing emitting hydrogen atoms.Key words. Ionosphere (auroral ionosphere; particle precipitation – Magnetospheric physics (auroral phenomena

Stellar parameters of Be stars observed with X-shooter

Science.gov (United States)

Shokry, A.; Rivinius, Th.; Mehner, A.; Martayan, C.; Hummel, W.; Townsend, R. H. D.; Mérand, A.; Mota, B.; Faes, D. M.; Hamdy, M. A.; Beheary, M. M.; Gadallah, K. A. K.; Abo-Elazm, M. S.

2018-01-01

Aims: The X-shooter archive of several thousand telluric standard star spectra was skimmed for Be and Be shell stars to derive the stellar fundamental parameters and statistical properties, in particular for the less investigated late-type Be stars and the extension of the Be phenomenon into early A stars. Methods: An adapted version of the BCD method is used, using the Balmer discontinuity parameters to determine effective temperature and surface gravity. This method is optimally suited for late B stars. The projected rotational velocity was obtained by profile fitting to the Mg ii lines of the targets, and the spectra were inspected visually for the presence of peculiar features such as the infrared Ca ii triplet or the presence of a double Balmer discontinuity. The Balmer line equivalent widths were measured, but they are only useful for determining the pure emission contribution in a subsample of Be stars owing to uncertainties in determining the photospheric contribution. Results: A total of 78, mostly late-type, Be stars, were identified in the X-shooter telluric standard star archive, out of which 48 had not been reported before. We confirm the general trend that late-type Be stars have more tenuous disks and are less variable than early-type Be stars. The relatively large number (48) of relatively bright (V> 8.5) additional Be stars casts some doubt on the statistics of late-type Be stars; they are more common than currently thought. The Be/B star fraction may not strongly depend on spectral subtype. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under program IDs 60.A-9022, 60.A-9024, 077.D-0085, 085.A-0962, 185.D-0056, 091.B-0900, and 093.D-0415.Table 6 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/609/A108

Line profile variability in B supergiants

Czech Academy of Sciences Publication Activity Database

Tomić, S.; Kraus, Michaela; Atanacković, O.

2017-01-01

Roč. 96, č. 1 (2017), s. 161-166 ISSN 0373-3742. [National Conference of Astronomers of Serbia /17./. Belgrade, 23.09.2014-27.09.2014] R&D Projects: GA ČR(CZ) GA14-21373S; GA MŠk LG14013 Institutional support: RVO:67985815 Keywords : supergiants * variability * macroturbulenc Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science)

Measurement of the Antiprotonic Lyman- and Balmer X-rays of $\\overline{p}H$ and $\\overline{p}D$ Atoms at Very Low Target Pressures

CERN Multimedia

2002-01-01

The aim of this experiment is to measure the energies and intensities of the n @A 1 (Lyman) and n @A 2 (Balmer) tansitions with high accuracy in both @*H and @*D, from which the strong interaction effects of the 1s- and 2p-level can be extracted. These observables may be related to the antiproton-proton and antiproton-neutron scattering length. \\\\ \\\\ Since in these targets collisional Stark effect occurs, we will stop the antiprotons in extreme thin gaseous targets (pressure as low as 10 Torr), where no Stark effect occurs and the 2-1 transition is favoured. In order to use antiprotons with high efficiency despite of the low target density, we will trap antiprotons of a momentum of 100 MeV/c in a magnetic field of cyclotron characteristics. The antiprotons are decelerated by their energy loss in the target gas. The focusing properties of the magnetic field serve to compensate the multiple scattering and we will end up with a concentrated stopping distribution at the centre. Due to the long orbiting time, back...

Potential of on-line visible and near infrared spectroscopy for measurement of pH for deriving variable rate lime recommendations.

Science.gov (United States)

Tekin, Yücel; Kuang, Boyan; Mouazen, Abdul M

2013-08-08

This paper aims at exploring the potential of visible and near infrared (vis-NIR) spectroscopy for on-line measurement of soil pH, with the intention to produce variable rate lime recommendation maps. An on-line vis-NIR soil sensor set up to a frame was used in this study. Lime application maps, based on pH predicted by vis-NIR techniques, were compared with maps based on traditional lab-measured pH. The validation of the calibration model using off-line spectra provided excellent prediction accuracy of pH (R2 = 0.85, RMSEP = 0.18 and RPD = 2.52), as compared to very good accuracy obtained with the on-line measured spectra (R2 = 0.81, RMSEP = 0.20 and RPD = 2.14). On-line predicted pH of all points (e.g., 2,160) resulted in the largest overall field virtual lime requirement (1.404 t), as compared to those obtained with 16 validation points off-line prediction (0.28 t), on-line prediction (0.14 t) and laboratory reference measurement (0.48 t). The conclusion is that the vis-NIR spectroscopy can be successfully used for the prediction of soil pH and for deriving lime recommendations. The advantage of the on-line sensor over sampling with limited number of samples is that more detailed information about pH can be obtained, which is the reason for a higher but precise calculated lime recommendation rate.

Potential of On-Line Visible and Near Infrared Spectroscopy for Measurement of pH for Deriving Variable Rate Lime Recommendations

Directory of Open Access Journals (Sweden)

Yücel Tekin

2013-08-01

Full Text Available This paper aims at exploring the potential of visible and near infrared (vis-NIR spectroscopy for on-line measurement of soil pH, with the intention to produce variable rate lime recommendation maps. An on-line vis-NIR soil sensor set up to a frame was used in this study. Lime application maps, based on pH predicted by vis-NIR techniques, were compared with maps based on traditional lab-measured pH. The validation of the calibration model using off-line spectra provided excellent prediction accuracy of pH (R2 = 0.85, RMSEP = 0.18 and RPD = 2.52, as compared to very good accuracy obtained with the on-line measured spectra (R2 = 0.81, RMSEP = 0.20 and RPD = 2.14. On-line predicted pH of all points (e.g., 2,160 resulted in the largest overall field virtual lime requirement (1.404 t, as compared to those obtained with 16 validation points off-line prediction (0.28 t, on-line prediction (0.14 t and laboratory reference measurement (0.48 t. The conclusion is that the vis-NIR spectroscopy can be successfully used for the prediction of soil pH and for deriving lime recommendations. The advantage of the on-line sensor over sampling with limited number of samples is that more detailed information about pH can be obtained, which is the reason for a higher but precise calculated lime recommendation rate.

Kendall-Theil Robust Line (KTRLine--version 1.0)-A Visual Basic Program for Calculating and Graphing Robust Nonparametric Estimates of Linear-Regression Coefficients Between Two Continuous Variables

Science.gov (United States)

Granato, Gregory E.

2006-01-01

The Kendall-Theil Robust Line software (KTRLine-version 1.0) is a Visual Basic program that may be used with the Microsoft Windows operating system to calculate parameters for robust, nonparametric estimates of linear-regression coefficients between two continuous variables. The KTRLine software was developed by the U.S. Geological Survey, in cooperation with the Federal Highway Administration, for use in stochastic data modeling with local, regional, and national hydrologic data sets to develop planning-level estimates of potential effects of highway runoff on the quality of receiving waters. The Kendall-Theil robust line was selected because this robust nonparametric method is resistant to the effects of outliers and nonnormality in residuals that commonly characterize hydrologic data sets. The slope of the line is calculated as the median of all possible pairwise slopes between points. The intercept is calculated so that the line will run through the median of input data. A single-line model or a multisegment model may be specified. The program was developed to provide regression equations with an error component for stochastic data generation because nonparametric multisegment regression tools are not available with the software that is commonly used to develop regression models. The Kendall-Theil robust line is a median line and, therefore, may underestimate total mass, volume, or loads unless the error component or a bias correction factor is incorporated into the estimate. Regression statistics such as the median error, the median absolute deviation, the prediction error sum of squares, the root mean square error, the confidence interval for the slope, and the bias correction factor for median estimates are calculated by use of nonparametric methods. These statistics, however, may be used to formulate estimates of mass, volume, or total loads. The program is used to read a two- or three-column tab-delimited input file with variable names in the first row and

Spectra of Wolf-Rayet stars. I. Optical line strengths and the hydrogen-to-helium ratios in WN type stars

International Nuclear Information System (INIS)

Conti, P.S.; Leep, E.M.; Perry, D.N.

1983-01-01

We begin a series of systematic studies of spectra of Wolf-Rayet stars by examining the optical line strengths of WN stars in the Galaxy and the Large Magellanic Cloud to see what similarities and differences exist among them. Tables of equivalent widths extracted from spectra are presented and some conclusions are drawn. We have found that there is a wide dispersion, up to a factor of 10 or more, in line strengths for all ions even among stars of the same subtype, with WN 7 stars weaker overall than surrounding types. Type-to-type trends are consistent with changing ionization balance in the stellar wind. Nitrogen line ratios indicate that the WN subtypes represent an ionization sequence, but one with considerable overlap: the classification scheme is not single valued; other physical parameters must play a role. The line strength dispersion does not appear to be primarily due to ionization, or luminosity. The Balmer-Pickering decrement has been used to estimate the H/He ratio for most of the WN stars with available spectra; semiquantitative results are presented. Significant differences in H/He are observed (10 stars may have H/He>2). At a given subclass, the strongest line stars have no detectable H. The abundance of H probably relates to structural differences in the winds that, in part, give rise to a dispersion in observed line strengths. Finally, we have estimated the C/N ratio from the C IV lambda5805/N IV lambda4057 line ratio. In most cases our observations suggest that the C/N ratio is consistent with ''evolved'' models for WN stars. A few stars show strong C IV implying much larger values for C/N, but hydrogen was not detected in them. These stars may be in transition from the WN to WC classes

Variability of snow line elevation, snow cover area and depletion in the main Slovak basins in winters 2001–2014

Directory of Open Access Journals (Sweden)

Krajčí Pavel

2016-03-01

Full Text Available Spatial and temporal variability of snow line (SL elevation, snow cover area (SCA and depletion (SCD in winters 2001–2014 is investigated in ten main Slovak river basins (the Western Carpathians. Daily satellite snow cover maps from MODIS Terra (MOD10A1, V005 and Aqua (MYD10A1, V005 with resolution 500 m are used.

Subshell differential cross sections for electron transfer in collisions of U{sup 90+} ions with gaseous targets

Energy Technology Data Exchange (ETDEWEB)

Ma, X. [Institute of Modern Physics, Lanzhou, GS (China); Stoehlker, T.; Bosch, F.; Brinzanescu, O.; Kozhuharov, C.; Mokler, P. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Fritzsche, S. [Kassel Univ. (Gesamthochschule) (Germany); Ludziejewski, T. [Institute of Nuclear Physics, Swierk (Poland); Warczak, A. [Uniwersytet Jagiellonski, Cracow (Poland). Inst. Fizyki

2000-10-01

Balmer spectra produced in collisions between He-like uranium projectiles and gaseous targets (N{sub 2}, Ar, Kr, and Xe) were measured at the jet-target area of the ESR storage ring. The X-ray radiation were recorded in coincidence with the down charged projectiles having captured one electron from the target atom. By means of spectra simulation, all the significant Balmer transition lines were identified. Further on, the j-differential cross sections for electron capture into projectile subshells were deduced from the well resolved spectra. For the heavier targets, where NRC contributes considerably, systematic deviations between experiment and the continuum distorted wave approximation are observed. (orig.)

Spectrographic observations of high intensity discharges; Observation spectrographique de decharges a forte intensite

Energy Technology Data Exchange (ETDEWEB)

Breton, C; Charon, J; Hubert, P; Yvon, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1957-07-01

During straight discharges in deuterium at low pressure, the production of X-rays and neutrons has been observed. Spectroscopic observation of the light emitted reveals a broadening of the Balmer lines. From this a mean ionic density of the order of several 10{sup 16} ions/cm{sup 3} is deduced. (author) [French] Au cours de decharges rectilignes dans le deuterium sous basse pression, la production de rayons X et de neutrons a ete observee. L'observation spectroscopique de la lumiere emise revele un elargissement des raies de Balmer. On en deduit une densite ionique moyenne de l'ordre de quelques 10{sup 16} ions/cm{sup 3}. (auteur)

Symbiotic binaries

International Nuclear Information System (INIS)

Mikolajewska, J.; Iijima, T.

1988-01-01

The symbiotic star BF Cyg shows periodic variations in its spectrum. [O3] line intensity changes in antiphase with the blue continuum, H-Balmer and He1 emission line intensity. These variations are interpreted in terms of a hot star moving on an eccentric orbit and ionizing a part of an M-type giant wind. 20 refs., 2 figs., 1 tab. (author)

DISCOVERY OF DRAMATIC OPTICAL VARIABILITY IN SDSS J1100+4421: A PECULIAR RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXY?

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Masaomi [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Morokuma, Tomoki; Doi, Mamoru; Kikuchi, Yuki [Institute of Astronomy, School of Science, University of Tokyo, Mitaka, Tokyo 181-0015 (Japan); Itoh, Ryosuke [Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Akitaya, Hiroshi; Tanaka, Yasuyuki T.; Kawabata, Koji S. [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Tominaga, Nozomu [Department of Physics, Faculty of Science and Engineering, Konan University, Kobe, Hyogo 658-8501 (Japan); Saito, Yoshihiko; Kawai, Nobuyuki [Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551 (Japan); Stawarz, Łukasz [Institute of Space and Astronautical Science, JAXA, Sagamihara, Kanagawa 252-5210 (Japan); Gandhi, Poshak [Department of Physics, Durham University, Durham DH1-3LE (United Kingdom); Ali, Gamal; Essam, Ahmad; Hamed, Gamal [National Research Institute of Astronomy and Geophysics, Helwan, Cairo (Egypt); Aoki, Tsutomu [Kiso Observatory, Institute of Astronomy, School of Science, The University of Tokyo, Kiso, Nagano 397-0101 (Japan); Contreras, Carlos; Hsiao, Eric Y. [Carnegie Observatories, Las Campanas Observatory, Colina El Pino, Casilla 601 (Chile); Iwata, Ikuru, E-mail: masaomi.tanaka@nao.ac.jp [Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720 (United States); and others

2014-10-01

We present our discovery of dramatic variability in SDSS J1100+4421 by the high-cadence transient survey Kiso Supernova Survey. The source brightened in the optical by at least a factor of three within about half a day. Spectroscopic observations suggest that this object is likely a narrow-line Seyfert 1 galaxy (NLS1) at z = 0.840, however, with unusually strong narrow emission lines. The estimated black hole mass of ∼10{sup 7} M {sub ☉} implies bolometric nuclear luminosity close to the Eddington limit. SDSS J1100+4421 is also extremely radio-loud, with a radio loudness parameter of R ≅ 4 × 10{sup 2}-3 × 10{sup 3}, which implies the presence of relativistic jets. Rapid and large-amplitude optical variability of the target, reminiscent of that found in a few radio- and γ-ray-loud NLS1s, is therefore produced most likely in a blazar-like core. The 1.4 GHz radio image of the source shows an extended structure with a linear size of about 100 kpc. If SDSS J1100+4421 is a genuine NLS1, as suggested here, this radio structure would then be the largest ever discovered in this type of active galaxies.

Hβ line profile variability of seven southern Be stars

International Nuclear Information System (INIS)

Mennickent, R.E.

1991-01-01

The results of spectroscopic observations of six B0-B4e and one B7e stars at the Manuel Foster Observatory (Chile) during 1984-87 are reported. By means of photographic spectroscopy (20 A/mm), equivalent widths, peak separations and V/R ratios were obtained for a total of 106 Hβ and 7 Hγ line profiles. Emission episodes in Hβ were detected in 27 CMa and λ Pav, lasting at least 5 months and 18 days respectively. Significant variations in the equivalent width of the Hβ emission line W β in time scales of months were found in κ CMa, PP Car and QY Car

Correcting for variable laser-target distances of laser-induced breakdown spectroscopy measurements with ChemCam using emission lines of Martian dust spectra

Energy Technology Data Exchange (ETDEWEB)

Melikechi, N.; Mezzacappa, A. [Optical Science Center for Applied Research, Delaware State University, Dover, DE (United States); Cousin, A.; Lanza, N.L. [Los Alamos National Laboratory, Los Alamos, NM (United States); Lasue, J. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Clegg, S.M. [Los Alamos National Laboratory, Los Alamos, NM (United States); Berger, G. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Wiens, R.C. [Los Alamos National Laboratory, Los Alamos, NM (United States); Maurice, S. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Tokar, R.L.; Bender, S. [Planetary Science Institute, Flagstaff, AZ (United States); Forni, O. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Breves, E.A.; Dyar, M.D. [Dept. of Astronomy, Mount Holyoke College, South Hadley, MA (United States); Frydenvang, J. [The Niels Bohr Institute, University of Copenhagen, Copenhagen (Denmark); Delapp, D. [Los Alamos National Laboratory, Los Alamos, NM (United States); Gasnault, O. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Newsom, H.; Ollila, A.M. [Earth and Planetary Sciences, University of New Mexico, Alburquerque, NM (United States); Lewin, E. [Institut des Sciences de la Terre, Universite Grenoble l-CNRS, Grenoble (France); and others

2014-06-01

As part of the Mars Science Laboratory, the ChemCam instrument acquires remote laser induced breakdown spectra at distances that vary between 1.56 m and 7 m. This variation in distance affects the intensities of the measured LIBS emission lines in non-trivial ways. To determine the behavior of a LIBS emission line with distance, it is necessary to separate the effects of many parameters such as laser energy, laser spot size, target homogeneity, and optical collection efficiency. These parameters may be controlled in a laboratory on Earth but for field applications or in space this is a challenge. In this paper, we show that carefully selected ChemCam LIBS emission lines acquired from the Martian dust can be used to build an internal proxy spectroscopic standard. This in turn, allows for a direct measurement of the effects of the distance of various LIBS emission lines and hence can be used to correct ChemCam LIBS spectra for distance variations. When tested on pre-launch LIBS calibration data acquired under Martian-like conditions and with controlled and well-calibrated targets, this approach yields much improved agreement between targets observed at various distances. This work lays the foundation for future implementation of automated routines to correct ChemCam spectra for differences caused by variable distance. - Highlights: • Selected Martian dust emission lines are used to correct for variable laser-target distances. • The correction model yields improved agreement between targets observed at various distances. • The impact of the model reduces the bias between predicted and actual compositions by as much as 70%. • When implemented, the model will yield spectral corrections for various ChemCam measurements. • This work is a foundation to perform novel stand-off LIBS measurements on Earth and other planets.

Hα line in the spectrum of HDE 245770

International Nuclear Information System (INIS)

Voikhanskaya, N.F.

1980-01-01

Constant and variable components are discriminated in the profile of the Hα emission line in the spectrum of the star HDE 245770. The variable component is formed near the degenerate component of the binary system. The constant part of the line has a steady radial velocity of +10 km/sec, while the variable part exhibits a radial-velocity curve having the same period, 104 sec, as the pulsations of the corresponding variable x-ray source A0535+26

Quality Assurance in the Presence of Variability

Science.gov (United States)

Lauenroth, Kim; Metzger, Andreas; Pohl, Klaus

Software Product Line Engineering (SPLE) is a reuse-driven development paradigm that has been applied successfully in information system engineering and other domains. Quality assurance of the reusable artifacts of the product line (e.g. requirements, design, and code artifacts) is essential for successful product line engineering. As those artifacts are reused in several products, a defect in a reusable artifact can affect several products of the product line. A central challenge for quality assurance in product line engineering is how to consider product line variability. Since the reusable artifacts contain variability, quality assurance techniques from single-system engineering cannot directly be applied to those artifacts. Therefore, different strategies and techniques have been developed for quality assurance in the presence of variability. In this chapter, we describe those strategies and discuss in more detail one of those strategies, the so called comprehensive strategy. The comprehensive strategy aims at checking the quality of all possible products of the product line and thus offers the highest benefits, since it is able to uncover defects in all possible products of the product line. However, the central challenge for applying the comprehensive strategy is the complexity that results from the product line variability and the large number of potential products of a product line. In this chapter, we present one concrete technique that we have developed to implement the comprehensive strategy that addresses this challenge. The technique is based on model checking technology and allows for a comprehensive verification of domain artifacts against temporal logic properties.

An X-ray survey of the central molecular zone: Variability of the Fe Kα emission line

Science.gov (United States)

Terrier, R.; Clavel, M.; Soldi, S.; Goldwurm, A.; Ponti, G.; Morris, M. R.; Chuard, D.

2018-05-01

There is now abundant evidence that the luminosity of the Galactic super-massive black hole (SMBH) has not always been as low as it is nowadays. The observation of varying non-thermal diffuse X-ray emission in molecular complexes in the central 300 pc has been interpreted as delayed reflection of a past illumination by bright outbursts of the SMBH. The observation of different variability timescales of the reflected emission in the Sgr A molecular complex can be well explained if the X-ray emission of at least two distinct and relatively short events (i.e. about 10 yr or less) is currently propagating through the region. The number of such events or the presence of a long-duration illumination are open questions. Variability of the reflected emission all over of the central 300 pc, in particular in the 6.4 keV Fe Kα line, can bring strong constraints. To do so we performed a deep scan of the inner 300 pc with XMM-Newton in 2012. Together with all the archive data taken over the course of the mission, and in particular a similar albeit more shallow scan performed in 2000-2001, this allows for a detailed study of variability of the 6.4 keV line emission in the region, which we present here. We show that the overall 6.4 keV emission does not strongly vary on average, but variations are very pronounced on smaller scales. In particular, most regions showing bright reflection emission in 2000-2001 significantly decrease by 2012. We discuss those regions and present newly illuminated features. The absence of bright steady emission argues against the presence of an echo from an event of multi-centennial duration and most, if not all, of the emission can likely be explained by a limited number of relatively short (i.e. up to 10 yr) events. Images of the Fe Kα emission as FITS files are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/612/A102

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

Science.gov (United States)

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

2001-11-01

An experimental search for variation in the fundamental coupling constants is strongly motivated by modern high-energy physics theories. Comparison of quasar (QSO) absorption-line spectra with laboratory spectra provides a sensitive probe for variability of the fine-structure constant, α, over cosmological time-scales. We have previously developed and applied a new method providing an order-of-magnitude gain in precision over previous optical astrophysical constraints. Here we extend that work by including new quasar spectra of damped Lyman-α absorption systems. We also reanalyse our previous lower-redshift data and confirm our initial results. The constraints on α come from simultaneous fitting of absorption lines of subsets of the following species: Mgi, Mgii, Alii, Aliii, Siii, Crii, Feii, Niii and Znii. We present a detailed description of our methods and results based on an analysis of 49 quasar absorption systems (towards 28 QSOs) covering the redshift range [formmu2]0.5quote above is the raw value, not corrected for any of these systematic effects. The only significant systematic effects so far identified, if removed from our data, would lead to a more significant deviation of [formmu5]Δα/α from zero.

Probing the Physics of Narrow-line Regions in Active Galaxies. IV. Full Data Release of the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7)

Energy Technology Data Exchange (ETDEWEB)

Thomas, Adam D.; Dopita, Michael A.; Davies, Rebecca; Hampton, Elise; Kewley, Lisa; Banfield, Julie; Groves, Brent; Sutherland, Ralph [RSAA, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Shastri, Prajval; Sairam, Lalitha [Indian Institute of Astrophysics, Sarjapur Road, Bengaluru 560034 (India); James, Bethan L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Jin, Chichuan [Max-Planck-Institut für Extraterrestrische Physik, Garching (Germany); Juneau, Stéphanie [CEA-Saclay, DSM/IRFU/SAp, F-91191 Gif-sur-Yvette (France); Kharb, Preeti [National Centre for Radio Astrophysics—Tata Institute of Fundamental Research, Pune University Campus, Post Bag 3, Ganeshkhind Pune 411007 (India); Scharwächter, Julia [Gemini Observatory, Northern Operations Center, 670 N. A’ohoku Place, Hilo, Hawaii 96720 (United States); Shalima, P. [Regional Institute of Education, Manasagangotri, Mysore 570006 (India); Sundar, M. N. [Jain University, 3rd Block Jayanagar, Bengaluru 560011 (India); Zaw, Ingyin, E-mail: adam.thomas@anu.edu.au [New York University (Abu Dhabi), 70 Washington Sq. S, New York, NY 10012 (United States)

2017-09-01

We present the second and final data release of the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). Data are presented for 63 new galaxies not included in the first data release, and we provide 2D emission-line fitting products for the full S7 sample of 131 galaxies. The S7 uses the WiFeS instrument on the ANU 2.3 m telescope to obtain spectra with a spectral resolution of R  = 7000 in the red (540–700 nm) and R  = 3000 in the blue (350–570 nm), over an integral field of 25 × 38 arcsec{sup 2} with 1 × 1 arcsec{sup 2} spatial pixels. The S7 contains both the largest sample of active galaxies and the highest spectral resolution of any comparable integral field survey to date. The emission-line fitting products include line fluxes, velocities, and velocity dispersions across the WiFeS field of view, and an artificial neural network has been used to determine the optimal number of Gaussian kinematic components for emission-lines in each spaxel. Broad Balmer lines are subtracted from the spectra of nuclear spatial pixels in Seyfert 1 galaxies before fitting the narrow lines. We bin nuclear spectra and measure reddening-corrected nuclear fluxes of strong narrow lines for each galaxy. The nuclear spectra are classified on optical diagnostic diagrams, where the strength of the coronal line [Fe vii] λ 6087 is shown to be correlated with [O iii]/H β . Maps revealing gas excitation and kinematics are included for the entire sample, and we provide notes on the newly observed objects.

DUST EXTINCTION FROM BALMER DECREMENTS OF STAR-FORMING GALAXIES AT 0.75 {<=} z {<=} 1.5 WITH HUBBLE SPACE TELESCOPE/WIDE-FIELD-CAMERA 3 SPECTROSCOPY FROM THE WFC3 INFRARED SPECTROSCOPIC PARALLEL SURVEY

Energy Technology Data Exchange (ETDEWEB)

Dominguez, A.; Siana, B.; Masters, D. [Department of Physics and Astronomy, University of California Riverside, Riverside, CA 92521 (United States); Henry, A. L.; Martin, C. L. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Scarlata, C.; Bedregal, A. G. [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Malkan, M.; Ross, N. R. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095 (United States); Atek, H.; Colbert, J. W. [Spitzer Science Center, Caltech, Pasadena, CA 91125 (United States); Teplitz, H. I.; Rafelski, M. [Infrared Processing and Analysis Center, Caltech, Pasadena, CA 91125 (United States); McCarthy, P.; Hathi, N. P.; Dressler, A. [Observatories of the Carnegie Institution for Science, Pasadena, CA 91101 (United States); Bunker, A., E-mail: albertod@ucr.edu [Department of Physics, Oxford University, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom)

2013-02-15

Spectroscopic observations of H{alpha} and H{beta} emission lines of 128 star-forming galaxies in the redshift range 0.75 {<=} z {<=} 1.5 are presented. These data were taken with slitless spectroscopy using the G102 and G141 grisms of the Wide-Field-Camera 3 (WFC3) on board the Hubble Space Telescope as part of the WFC3 Infrared Spectroscopic Parallel survey. Interstellar dust extinction is measured from stacked spectra that cover the Balmer decrement (H{alpha}/H{beta}). We present dust extinction as a function of H{alpha} luminosity (down to 3 Multiplication-Sign 10{sup 41} erg s{sup -1}), galaxy stellar mass (reaching 4 Multiplication-Sign 10{sup 8} M {sub Sun }), and rest-frame H{alpha} equivalent width. The faintest galaxies are two times fainter in H{alpha} luminosity than galaxies previously studied at z {approx} 1.5. An evolution is observed where galaxies of the same H{alpha} luminosity have lower extinction at higher redshifts, whereas no evolution is found within our error bars with stellar mass. The lower H{alpha} luminosity galaxies in our sample are found to be consistent with no dust extinction. We find an anti-correlation of the [O III] {lambda}5007/H{alpha} flux ratio as a function of luminosity where galaxies with L {sub H{alpha}} < 5 Multiplication-Sign 10{sup 41} erg s{sup -1} are brighter in [O III] {lambda}5007 than H{alpha}. This trend is evident even after extinction correction, suggesting that the increased [O III] {lambda}5007/H{alpha} ratio in low-luminosity galaxies is likely due to lower metallicity and/or higher ionization parameters.

[The radial velocity measurement accuracy of different spectral type low resolution stellar spectra at different signal-to-noise ratio].

Science.gov (United States)

Wang, Feng-Fei; Luo, A-Li; Zhao, Yong-Heng

2014-02-01

The radial velocity of the star is very important for the study of the dynamics structure and chemistry evolution of the Milky Way, is also an useful tool for looking for variable or special objects. In the present work, we focus on calculating the radial velocity of different spectral types of low-resolution stellar spectra by adopting a template matching method, so as to provide effective and reliable reference to the different aspects of scientific research We choose high signal-to-noise ratio (SNR) spectra of different spectral type stellar from the Sloan Digital Sky Survey (SDSS), and add different noise to simulate the stellar spectra with different SNR. Then we obtain theradial velocity measurement accuracy of different spectral type stellar spectra at different SNR by employing a template matching method. Meanwhile, the radial velocity measurement accuracy of white dwarf stars is analyzed as well. We concluded that the accuracy of radial velocity measurements of early-type stars is much higher than late-type ones. For example, the 1-sigma standard error of radial velocity measurements of A-type stars is 5-8 times as large as K-type and M-type stars. We discuss the reason and suggest that the very narrow lines of late-type stars ensure the accuracy of measurement of radial velocities, while the early-type stars with very wide Balmer lines, such as A-type stars, become sensitive to noise and obtain low accuracy of radial velocities. For the spectra of white dwarfs stars, the standard error of radial velocity measurement could be over 50 km x s(-1) because of their extremely wide Balmer lines. The above conclusion will provide a good reference for stellar scientific study.

Hα line in the spectrum of the HDE 245770 star

International Nuclear Information System (INIS)

Vojkhanskaya, N.F.

1980-01-01

The emission line Hα in the spectrum of HDE 245770 is devided into constant and variable components. The latter is shown to be a line arising in the vicinity of the degenerated components of the system. The radial velocity of the constant part of the line does not vary and equals to +10 km/s. For the variable line component a curve of radial velocities that varies with a period of 104 s is obtained. The period is the same as that of pulsations of the X-ray flux from the variable source A 0535+26

Magnetic field evidence for the supergiant ν Cep (HD 207260)

International Nuclear Information System (INIS)

Scholz, G.; Gerth, E.

1981-01-01

On the basis of 55 Zeeman spectrograms the effective magnetic fields and the radial velocities of the supergiant ν Cep (HD 207260) were determined. For the effective magnetic field a slow variation occurring on a time-scale of years was found. The spectrograms taken at the first epoch show only moderate effective magnetic field strengths of a few hundred Gauss but in 1978 values of + 2000 G were detected. The measured radial velocities show a long-term variability similar to that of the magnetic field as well as more rapid changes of approximately equal to 39.9 day. Not only the Balmer absorption lines Hβ, Hγ, and Hdelta but also the various elements and ions have different radial velocities. (author)

Long term X-ray variability characteristics of the narrow-line Seyfert 1 galaxy RE J1034+396

Science.gov (United States)

Chaudhury, K.; Chitnis, V. R.; Rao, A. R.; Singh, K. P.; Bhattacharyya, Sudip; Dewangan, G. C.; Chakraborty, S.; Chandra, S.; Stewart, G. C.; Mukerjee, K.; Dey, R. K.

2018-05-01

We present the results of our study of the long term X-ray variability characteristics of the Narrow Line Seyfert 1 galaxy RE J1034+396. We use data obtained from the AstroSat satellite along with the light curves obtained from XMM-Newton and Swift-XRT. We use the 0.3 - 7.0 keV and 3 - 20 keV data, respectively, from the SXT and the LAXPC of AstroSat. The X-ray spectra in the 0.3 - 20 keV region are well fit with a model consisting of a power-law and a soft excess described by a thermal-Compton emission with a large optical depth, consistent with the earlier reported results. We have examined the X-ray light curves in the soft and hard X-ray bands of SXT and LAXPC, respectively, and find that the variability is slightly larger in the hard band. To investigate the variability characteristics of this source at different time scales, we have used X-ray light curves obtained from XMM-Newton data (200 s to 100 ks range) and Swift-XRT data (1 day to 100 day range) and find that there are evidences to suggest that the variability sharply increases at longer time scales. We argue that the mass of the black hole in RE J1034+396 is likely to be ˜3 × 106 M⊙, based on the similarity of the observed QPO to the high frequency QPO seen in the Galactic black hole binary, GRS 1915+105.

TIME-RESOLVED PROPERTIES AND GLOBAL TRENDS IN dMe FLARES FROM SIMULTANEOUS PHOTOMETRY AND SPECTRA

Energy Technology Data Exchange (ETDEWEB)

Kowalski, Adam F.; Hawley, Suzanne L.; Davenport, James R. A. [Astronomy Department, University of Washington, Box 351580, U.W. Seattle, WA 98195-1580 (United States); Wisniewski, John P. [HL Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W Brooks Street, Norman, OK 73019 (United States); Osten, Rachel A. [Space Telescope Science Institute, 3700 San Martin Drive Baltimore, MD 21218 (United States); Hilton, Eric J. [Universe Sandbox, Seattle, WA (United States); Holtzman, Jon A. [Department of Astronomy, New Mexico State University, Box 30001, Las Cruces, NM 88003 (United States); Schmidt, Sarah J., E-mail: adam.f.kowalski@nasa.gov [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)

2013-07-15

We present a homogeneous analysis of line and continuum emission from simultaneous high-cadence spectra and photometry covering near-ultraviolet and optical wavelengths for 20 M dwarf flares. These data were obtained to study the white-light continuum components at bluer and redder wavelengths than the Balmer jump. Our goals were to break the degeneracy between emission mechanisms that have been fit to broadband colors of flares and to provide constraints for radiative-hydrodynamic (RHD) flare models that seek to reproduce the white-light flare emission. The main results from the analysis are the following: (1) the detection of Balmer continuum (in emission) that is present during all flares and with a wide range of relative contributions to the continuum flux at bluer wavelengths than the Balmer jump; (2) a blue continuum at flare maximum that is linearly decreasing with wavelength from {lambda} = 4000-4800 A, indicative of hot, blackbody emission with typical temperatures of T{sub BB} {approx} 9000-14, 000 K; (3) a redder continuum apparent at wavelengths longer than H{beta} ({lambda} {approx}> 4900 A) which becomes relatively more important to the energy budget during the late gradual phase. The hot blackbody component and redder continuum component have been detected in previous studies of flares. However, we have found that although the hot blackbody emission component is relatively well-represented by a featureless, single-temperature Planck function, this component includes absorption features and has a continuum shape strikingly similar to the spectrum of an A-type star as directly observed in our flare spectra. New model constraints are presented for the time evolution among the hydrogen Balmer lines and between Ca II K and the blackbody continuum emission. We calculate Balmer jump flux ratios and compare to the solar-type flare heating predictions from RHD models. The model ratios are too large and the blue-optical ({lambda} = 4000-4800 A) slopes are too

TIME-RESOLVED PROPERTIES AND GLOBAL TRENDS IN dMe FLARES FROM SIMULTANEOUS PHOTOMETRY AND SPECTRA

International Nuclear Information System (INIS)

Kowalski, Adam F.; Hawley, Suzanne L.; Davenport, James R. A.; Wisniewski, John P.; Osten, Rachel A.; Hilton, Eric J.; Holtzman, Jon A.; Schmidt, Sarah J.

2013-01-01

We present a homogeneous analysis of line and continuum emission from simultaneous high-cadence spectra and photometry covering near-ultraviolet and optical wavelengths for 20 M dwarf flares. These data were obtained to study the white-light continuum components at bluer and redder wavelengths than the Balmer jump. Our goals were to break the degeneracy between emission mechanisms that have been fit to broadband colors of flares and to provide constraints for radiative-hydrodynamic (RHD) flare models that seek to reproduce the white-light flare emission. The main results from the analysis are the following: (1) the detection of Balmer continuum (in emission) that is present during all flares and with a wide range of relative contributions to the continuum flux at bluer wavelengths than the Balmer jump; (2) a blue continuum at flare maximum that is linearly decreasing with wavelength from λ = 4000-4800 Å, indicative of hot, blackbody emission with typical temperatures of T BB ∼ 9000-14, 000 K; (3) a redder continuum apparent at wavelengths longer than Hβ (λ ∼> 4900 Å) which becomes relatively more important to the energy budget during the late gradual phase. The hot blackbody component and redder continuum component have been detected in previous studies of flares. However, we have found that although the hot blackbody emission component is relatively well-represented by a featureless, single-temperature Planck function, this component includes absorption features and has a continuum shape strikingly similar to the spectrum of an A-type star as directly observed in our flare spectra. New model constraints are presented for the time evolution among the hydrogen Balmer lines and between Ca II K and the blackbody continuum emission. We calculate Balmer jump flux ratios and compare to the solar-type flare heating predictions from RHD models. The model ratios are too large and the blue-optical (λ = 4000-4800 Å) slopes are too red in both the impulsive and

Metabolic Response to NAD Depletion across Cell Lines Is Highly Variable.

Science.gov (United States)

Xiao, Yang; Kwong, Mandy; Daemen, Anneleen; Belvin, Marcia; Liang, Xiaorong; Hatzivassiliou, Georgia; O'Brien, Thomas

2016-01-01

Nicotinamide adenine dinucleotide (NAD) is a cofactor involved in a wide range of cellular metabolic processes and is a key metabolite required for tumor growth. NAMPT, nicotinamide phosphoribosyltransferase, which converts nicotinamide (NAM) to nicotinamide mononucleotide (NMN), the immediate precursor of NAD, is an attractive therapeutic target as inhibition of NAMPT reduces cellular NAD levels and inhibits tumor growth in vivo. However, there is limited understanding of the metabolic response to NAD depletion across cancer cell lines and whether all cell lines respond in a uniform manner. To explore this we selected two non-small cell lung carcinoma cell lines that are sensitive to the NAMPT inhibitor GNE-617 (A549, NCI-H1334), one that shows intermediate sensitivity (NCI-H441), and one that is insensitive (LC-KJ). Even though NAD was reduced in all cell lines there was surprising heterogeneity in their metabolic response. Both sensitive cell lines reduced glycolysis and levels of di- and tri-nucleotides and modestly increased oxidative phosphorylation, but they differed in their ability to combat oxidative stress. H1334 cells activated the stress kinase AMPK, whereas A549 cells were unable to activate AMPK as they contain a mutation in LKB1, which prevents activation of AMPK. However, A549 cells increased utilization of the Pentose Phosphate pathway (PPP) and had lower reactive oxygen species (ROS) levels than H1334 cells, indicating that A549 cells are better able to modulate an increase in oxidative stress. Inherent resistance of LC-KJ cells is associated with higher baseline levels of NADPH and a delayed reduction of NAD upon NAMPT inhibition. Our data reveals that cell lines show heterogeneous response to NAD depletion and that the underlying molecular and genetic framework in cells can influence the metabolic response to NAMPT inhibition.

Metabolic Response to NAD Depletion across Cell Lines Is Highly Variable.

Directory of Open Access Journals (Sweden)

Yang Xiao

Full Text Available Nicotinamide adenine dinucleotide (NAD is a cofactor involved in a wide range of cellular metabolic processes and is a key metabolite required for tumor growth. NAMPT, nicotinamide phosphoribosyltransferase, which converts nicotinamide (NAM to nicotinamide mononucleotide (NMN, the immediate precursor of NAD, is an attractive therapeutic target as inhibition of NAMPT reduces cellular NAD levels and inhibits tumor growth in vivo. However, there is limited understanding of the metabolic response to NAD depletion across cancer cell lines and whether all cell lines respond in a uniform manner. To explore this we selected two non-small cell lung carcinoma cell lines that are sensitive to the NAMPT inhibitor GNE-617 (A549, NCI-H1334, one that shows intermediate sensitivity (NCI-H441, and one that is insensitive (LC-KJ. Even though NAD was reduced in all cell lines there was surprising heterogeneity in their metabolic response. Both sensitive cell lines reduced glycolysis and levels of di- and tri-nucleotides and modestly increased oxidative phosphorylation, but they differed in their ability to combat oxidative stress. H1334 cells activated the stress kinase AMPK, whereas A549 cells were unable to activate AMPK as they contain a mutation in LKB1, which prevents activation of AMPK. However, A549 cells increased utilization of the Pentose Phosphate pathway (PPP and had lower reactive oxygen species (ROS levels than H1334 cells, indicating that A549 cells are better able to modulate an increase in oxidative stress. Inherent resistance of LC-KJ cells is associated with higher baseline levels of NADPH and a delayed reduction of NAD upon NAMPT inhibition. Our data reveals that cell lines show heterogeneous response to NAD depletion and that the underlying molecular and genetic framework in cells can influence the metabolic response to NAMPT inhibition.

Spectroscopic Peculiarity of the Herbig Be Star HD 259431

Science.gov (United States)

Pogodin, M. A.; Pavlovskij, S. E.; Drake, N. A.; Beskrovnaya, N. G.; Kozlova, O. V.; Alekseev, I. Yu.; Borges Fernandes, M.; Pereira, C. B.; Valyavin, G.

2017-06-01

High-resolution spectra of the Herbig Be star HD 259431 obtained in 2010-2016 at three observatories (Crimean AO, ESO in Chile, and OAN SPN in Mexico) are analysed. The object demonstrates a very rich emission line profile spectrum. The bulk of the lines exhibit double-peaked emission profiles and originate in the gaseous disk. The atmospheric lines are unusually shallow, and majority of them are distorted by the circumstellar (CS) contribution. Moreover, we have revealed that they are overlapped with an additional continuum emission. Using the observed ratio of the equivalent widths of two He I λ 4009 and 4026 lines, we estimated the spectral type of the object as B5 V. We also constructed the spectral energy distribution of the additional continuum using wide wings of the atmospheric Hβ-Hɛ lines free of the CS contribution. The continuum corresponds to the blue part of the black body spectrum. The Hβ - Hɛ Balmer emission lines show very variable profiles looking as either of P Cyg-type or a double-peaked emission line with a depression of the red wing. We found the period of this variability P = 2.630d and interpreted it as a sign of a rotating magnetosphere of the star with the magnetic axis inclined to the rotation axis. At different phases of rotation, the observer can see either an accretion flow at high magnetic latitudes or a wind zone at lower latitudes. We also estimated the inclination of the rotation axis i = 52°±1°.

Productivity and fishing pressure drive variability in fish parasite assemblages of the Line Islands, equatorial Pacific.

Science.gov (United States)

Wood, Chelsea L; Baum, Julia K; Reddy, Sheila M W; Trebilco, Rowan; Sandin, Stuart A; Zgliczynski, Brian J; Briggs, Amy A; Micheli, Fiorenza

2015-05-01

Variability in primary productivity and fishing pressure can shape the abundance, species composition, and diversity of marine life. Though parasites comprise nearly half of marine species, their responses to these important forces remain little explored. We quantified parasite assemblages at two spatial scales, across a gradient in productivity and fishing pressure that spans six coral islands of the Line Islands archipelago and within the largest Line Island, Kiritimati, which experiences a west-to-east gradient in fishing pressure and upwelling-driven productivity. In the across-islands data set, we found that increasing productivity was correlated with increased parasite abundance overall, but that the effects of productivity differed among parasite groups. Trophically transmitted parasites increased in abundance with increasing productivity, but directly transmitted parasites did not exhibit significant changes. This probably arises because productivity has stronger effects on the abundance of the planktonic crustaceans and herbivorous snails that serve as the intermediate hosts of trophically transmitted parasites than on the higher-trophic level fishes that are the sole hosts of directly transmitted parasites. We also found that specialist parasites increased in response to increasing productivity, while generalists did not, possibly because specialist parasites tend to be more strongly limited by host availability than are generalist parasites. After the effect of productivity was controlled for, fishing was correlated with decreases in the abundance of trophically transmitted parasites, while directly transmitted parasites appeared to track host density; we observed increases in the abundance of parasites using hosts that experienced fishing-driven compensatory increases in abundance. The within-island data set confirmed these patterns for the combined effects of productivity and fishing on parasite abundance, suggesting that our conclusions are robust

Tracers of Chromospheric Structure. I. Observations of Ca II K and Hα in M Dwarfs

Science.gov (United States)

Walkowicz, Lucianne M.; Hawley, Suzanne L.

2009-02-01

We report on our observing program4This paper is based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. to capture simultaneous spectra of Ca II and Balmer lines in a sample of nearby M3 dwarfs. Our goal is to investigate the chromospheric temperature structure required to produce these lines at the observed levels. We find a strong positive correlation between instantaneous measurements of Ca II K and the Balmer lines in active stars, although these lines may not be positively correlated in time-resolved measurements. The relationship between Hα and Ca II K remains ambiguous for weak and intermediate activity stars, with Hα absorption corresponding to a range of Ca II K emission. A similar relationship is also observed between Ca II K and the higher-order Balmer lines. As our sample consists of a single spectral type, correlations between these important chromospheric tracers cannot be ascribed to continuum effects, as suggested by other authors. These data confirm prior nonsimultaneous observations of the Hα line behavior with increasing activity, showing an initial increase in the Hα absorption with increasing Ca II K emission, prior to Hα filling in and eventually becoming a pure emission line in the most active stars. We also compare our optical measurements with archival UV and X-ray measurements, finding a positive correlation between the chromospheric and coronal emission for both high and intermediate activity stars. We compare our results with previous determinations of the active fraction of low-mass stars

Spectrographic observations of high intensity discharges

International Nuclear Information System (INIS)

Breton, C.; Charon, J.; Hubert, P.; Yvon, P.

1957-01-01

During straight discharges in deuterium at low pressure, the production of X-rays and neutrons has been observed. Spectroscopic observation of the light emitted reveals a broadening of the Balmer lines. From this a mean ionic density of the order of several 10 16 ions/cm 3 is deduced. (author) [fr

On the limitations of statistical absorption studies with the Sloan Digital Sky Surveys I-III

Science.gov (United States)

Lan, Ting-Wen; Ménard, Brice; Baron, Dalya; Johnson, Sean; Poznanski, Dovi; Prochaska, J. Xavier; O'Meara, John M.

2018-04-01

We investigate the limitations of statistical absorption measurements with the SDSS optical spectroscopic surveys. We show that changes in the data reduction strategy throughout different data releases have led to a better accuracy at long wavelengths, in particular for sky line subtraction, but a degradation at short wavelengths with the emergence of systematic spectral features with an amplitude of about one percent. We show that these features originate from inaccuracy in the fitting of modeled F-star spectra used for flux calibration. The best-fit models for those stars are found to systematically over-estimate the strength of metal lines and under-estimate that of Lithium. We also identify the existence of artifacts due to masking and interpolation procedures at the wavelengths of the hydrogen Balmer series leading to the existence of artificial Balmer α absorption in all SDSS optical spectra. All these effects occur in the rest-frame of the standard stars and therefore present Galactic longitude variations due to the rotation of the Galaxy. We demonstrate that the detection of certain weak absorption lines reported in the literature are solely due to calibration effects. Finally, we discuss new strategies to mitigate these issues.

Dynamical study of merger remnants

International Nuclear Information System (INIS)

Lake, G.; Dressler, A.; ATandT Bell Labs., Murray Hill, NJ; Mount Wilson and Las Campanas Observatories, Pasadena, CA; Carnegie Institution of Washington, Washington, DC)

1986-01-01

The velocity dispersion of objects from the Arp and the Arp-Madore atlases that have characteristics of recently merged galaxies is measured. These data are used to test the hypothesis that the remnants become normal elliptical galaxies after the fireworks of recent star formation subside. Accurate velocity dispersions of objects dominated by Balmer lines in the blue were measured using the uncontaminated Ca triplet feature in the extreme red (8400-8700 A). No deviation from the velocity dispersion expected for elliptical galaxies of comparable luminosity, is found, e.g., these systems follow the usual L-sigma relation with no zero-point shift. For a few galaxies without Balmer contamination, stellar rotation velocities are determined. One slow, one moderate, and one fast rotator are found. 54 references

THE IMPORTANCE OF NEBULAR CONTINUUM AND LINE EMISSION IN OBSERVATIONS OF YOUNG MASSIVE STAR CLUSTERS

International Nuclear Information System (INIS)

Reines, Amy E.; Nidever, David L.; Whelan, David G.; Johnson, Kelsey E.

2010-01-01

In this spectroscopic study of infant massive star clusters, we find that continuum emission from ionized gas rivals the stellar luminosity at optical wavelengths. In addition, we find that nebular line emission is significant in many commonly used broadband Hubble Space Telescope (HST) filters including the F814W I-band, the F555W V-band, and the F435W B-band. Two young massive clusters (YMCs) in the nearby starburst galaxy NGC 4449 were targeted for follow-up spectroscopic observations after Reines et al. discovered an F814W I-band excess in their photometric study of radio-detected clusters in the galaxy. The spectra were obtained with the Dual Imaging Spectrograph (DIS) on the 3.5 m Apache Point Observatory (APO) telescope and have a spectral range of ∼3800-9800 A. We supplement these data with HST and Sloan Digital Sky Survey photometry of the clusters. By comparing our data to the Starburst99 and GALEV evolutionary synthesis models, we find that nebular continuum emission competes with the stellar light in our observations and that the relative contribution from the nebular continuum is largest in the U- and I-bands, where the Balmer (3646 A) and Paschen jumps (8207 A) are located. The spectra also exhibit strong line emission including the [S III] λλ9069, 9532 lines in the HST F814W I-band. We find that the combination of nebular continuum and line emission can account for the F814W I-band excess previously found by Reines et al. In an effort to provide a benchmark for estimating the impact of ionized gas emission on photometric observations of young massive stellar populations, we compute the relative contributions of the stellar continuum, nebular continuum, and emission lines to the total observed flux of a 3 Myr old cluster through various HST filter/instrument combinations, including filters in the Wide Field Camera 3. We urge caution when comparing observations of YMCs to evolutionary synthesis models since nebular continuum and line emission can

Investigation of X-ray lasing in a capillary discharge

NARCIS (Netherlands)

Ellwi, S. S.; Juschkin, L.; Ferri, S.; Kunze, H. J.; E. Louis,

2001-01-01

Using a new technique of an induced MHD instability in a capillary made of polyacetal we observed an intense spike (signal) of the Balmer-a line of C VI at 18.22 nm during the second half cycle of the discharge. The spike is identified as Amplified Spontaneous Emission (ASE), and enhancements are

SN 2009kn - the twin of the Type IIn supernova 1994W

DEFF Research Database (Denmark)

Kankare, E.; Ergon, M.; Bufano, F.

2012-01-01

We present an optical and near-infrared photometric and spectroscopic study of supernova (SN) 2009kn spanning ~1.5 yr from the discovery. The optical spectra are dominated by the narrow (full width at half-maximum ~1000 km s^-1) Balmer lines distinctive of a Type IIn SN with P Cygni profiles. Con...

Several complex variables

International Nuclear Information System (INIS)

Field, M.J.

1976-01-01

Topics discussed include the elementary of holomorphic functions of several complex variables; the Weierstrass preparation theorem; meromorphic functions, holomorphic line bundles and divisors; elliptic operators on compact manifolds; hermitian connections; the Hodge decomposition theorem. ( author)

MINUTE-SCALE RAPID VARIABILITY OF THE OPTICAL POLARIZATION IN THE NARROW-LINE SEYFERT 1 GALAXY PMN J0948+0022

Energy Technology Data Exchange (ETDEWEB)

Itoh, Ryosuke; Tanaka, Yasuyuki T.; Fukazawa, Yasushi; Kawaguchi, Kenji; Takaki, Katsutoshi; Ueno, Issei [Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Kawabata, Koji S.; Moritani, Yuki; Uemura, Makoto; Akitaya, Hiroshi; Yoshida, Michitoshi; Ohsugi, Takashi [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Hanayama, Hidekazu; Miyaji, Takeshi [Ishigakijima Astronomical Observatory, National Astronomical Observatory of Japan, 1024-1 Arakawa, Ishigaki, Okinawa 907-0024 (Japan); Kawai, Nobuyuki, E-mail: itoh@hep01.hepl.hiroshima-u.ac.jp [Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)

2013-09-20

We report on optical photopolarimetric results of the radio-loud narrow-line Seyfert 1 (RL-NLSy1) galaxy PMN J0948+0022 on 2012 December to 2013 February triggered by flux enhancements in the near infrared and γ-ray bands. With the one-shot polarimetry of the Hiroshima One-shot Wide field Polarimeter installed on the Kanata Telescope, we detected very rapid variability in the polarized-flux (PF) light curve on MJD 56281 (2012 December 20). The rise and decay times were about 140 s and 180 s, respectively. The polarization degree (PD) reached 36% ± 3% at the peak of the short-duration pulse, while the polarization angle remained almost constant. In addition, temporal profiles of the total flux and PD showed highly variable but well correlated behavior and discrete correlation function analysis revealed that no significant time lag of more than 10 minutes was present. The high PD and minute-scale variability in PF provides clear evidence of synchrotron radiation from a very compact emission region of ∼10{sup 14} cm size with a highly ordered magnetic field. Such micro-variability of polarization is also observed in several blazar jets, but its complex relation between total flux and PD are explained by a multi-zone model in several blazars. The implied single emission region in PMN J0948+0022 might reflect a difference of jets between RL-NLSy1s and blazars.

DETECTION OF BROAD Hα EMISSION LINES IN THE LATE-TIME SPECTRA OF A HYDROGEN-POOR SUPERLUMINOUS SUPERNOVA

Energy Technology Data Exchange (ETDEWEB)

Yan, Lin; Masci, F. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Quimby, R. [Department of Astronomy, San Diego State University, San Diego, CA 92182 (United States); Ofek, E.; Gal-Yam, A.; Vreeswijk, P. M.; Leloudas, G.; Cia, A. de; Yaron, O. [Department of Particle Physics and Astrophysics, Faculty of Physics, The Weizmann Institute of Science, Rehovot 76100 (Israel); Mazzali, P. [Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom); Perley, D. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Cenko, S. B. [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Cao, Y.; Kulkarni, S. R. [Astronomy Department, California Institute of Technology, Pasadena, CA 91125 (United States); Nugent, P. E. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Rebbapragada, Umaa D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Woźniak, P. R., E-mail: lyan@ipac.caltech.edu [Space and Remote Sensing, ISR-2, MS-B244 Los Alamos National Laboratory Los Alamos, NM 87545 (United States)

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, 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.

Asymmetry of Hβ Stark profiles in T-tube hydrogen plasma

International Nuclear Information System (INIS)

Djurovic, S.; Nikolic, D.; Savic, I.; Soerge, S.; Demura, A. V.

2005-01-01

The whole Balmer H β line profiles are studied in detail experimentally in the T-tube discharge for the wide range of plasma parameters. Besides the common one, two additional parameters are introduced to characterize the asymmetry behavior of the experimental Stark profiles with the reference point chosen in the center of the line. The experimental data are analyzed and benchmarked versus the simple theoretical model based on the effects of microfield nonuniformity and electron impact shifts

Partial dust obscuration in active galactic nuclei as a cause of broad-line profile and lag variability, and apparent accretion disc inhomogeneities

Science.gov (United States)

Gaskell, C. Martin; Harrington, Peter Z.

2018-04-01

The profiles of the broad emission lines of active galactic nuclei (AGNs) and the time delays in their response to changes in the ionizing continuum ("lags") give information about the structure and kinematics of the inner regions of AGNs. Line profiles are also our main way of estimating the masses of the supermassive black holes (SMBHs). However, the profiles often show ill-understood, asymmetric structure and velocity-dependent lags vary with time. Here we show that partial obscuration of the broad-line region (BLR) by outflowing, compact, dusty clumps produces asymmetries and velocity-dependent lags similar to those observed. Our model explains previously inexplicable changes in the ratios of the hydrogen lines with time and velocity, the lack of correlation of changes in line profiles with variability of the central engine, the velocity dependence of lags, and the change of lags with time. We propose that changes on timescales longer than the light-crossing time do not come from dynamical changes in the BLR, but are a natural result of the effect of outflowing dusty clumps driven by radiation pressure acting on the dust. The motion of these clumps offers an explanation of long-term changes in polarization. The effects of the dust complicate the study of the structure and kinematics of the BLR and the search for sub-parsec SMBH binaries. Partial obscuration of the accretion disc can also provide the local fluctuations in luminosity that can explain sizes deduced from microlensing.

The Stark-crossing method for the simultaneous determination of the electron temperature and density in plasmas

International Nuclear Information System (INIS)

Torres, J; Carabano, O; Fernandez, M; Rubio, S; Alvarez, R; Rodero, A; Lao, C; Quintero, M C; Gamero, A; Sola, A

2006-01-01

The use of the Stark broadening of Balmer lines spontaneously emitted by atmospheric-pressure plasmas as a method to determine both the electron density and temperature in high-pressure plasmas is discussed in this paper. This method is applied to argon and helium plasmas produced in microwave discharges. Especially for Ar plasmas, valuable and reliable results are obtained

Identification of SDSS J141324.27+530527.0 as a New “Changing-look” Quasar with a “Turn-on” Transition

Science.gov (United States)

Wang, J.; Xu, D. W.; Wei, J. Y.

2018-05-01

We report an identification of SDSS J141324+530527.0 (SBS 1411+533) at z = 0.456344 as a new “changing-look” quasar with a “turn-on” spectral type transition from Type-1.9/2 to Type-1 within a rest-frame timescale of 1–10 yr by a comparison of our new spectroscopic observation and the Sloan Digital Sky Survey (SDSS) archive database. The SDSS DR7 spectrum taken in 2003 is dominated by a starlight emission from host galaxy redward of the Balmer limit, and has a non-detectable broad Hβ line. The new spectrum taken by us on 2017 June 1 and the SDSS DR14 spectrum taken on 2017 May 29 indicate that the object has a typical quasar spectrum with a blue continuum and strong Balmer broad emission lines. In addition, an intermediate spectral type can be identified in the SDSS DR13 spectrum taken in 2015. The invariability of the line wing of Mg II λ2800 emission and timescale argument (the invariability of [O III]λ5007 line blue asymmetry) suggests that a variation of obscuration (an accelerating outflow) is not a favorable scenario. The timescale argument allows us to believe the type transition is possibly caused by either a viscous radial inflow or a disk instability around a ∼ (5{--}9)× {10}7 {M}ȯ black hole.

Modification of beam lines at VEC

Energy Technology Data Exchange (ETDEWEB)

Shoor, Bivas; Chakraborty, P S; Mallik, C; Bhandari, R K [Variable Energy Cyclotron Centre, Calcutta (India)

1997-12-01

From the experience of light ion beam transportation through the Variable Energy Cyclotron beam line, it was observed that the beam line performance has to be improved in view of heavy ion acceleration program at the centre. The aim of this work was to study the feasibility of reducing the number of operational parameters without hampering the beam transmission and at the same time, to improve the vacuum of the beam line by reducing the hardware 2 refs., 1 fig.

Security Requirements Management in Software Product Line Engineering

Science.gov (United States)

Mellado, Daniel; Fernández-Medina, Eduardo; Piattini, Mario

Security requirements engineering is both a central task and a critical success factor in product line development due to the complexity and extensive nature of product lines. However, most of the current product line practices in requirements engineering do not adequately address security requirements engineering. Therefore, in this chapter we will propose a security requirements engineering process (SREPPLine) driven by security standards and based on a security requirements decision model along with a security variability model to manage the variability of the artefacts related to security requirements. The aim of this approach is to deal with security requirements from the early stages of the product line development in a systematic way, in order to facilitate conformance with the most relevant security standards with regard to the management of security requirements, such as ISO/IEC 27001 and ISO/IEC 15408.

Rapidly variable relatvistic absorption

Science.gov (United States)

Parker, M.; Pinto, C.; Fabian, A.; Lohfink, A.; Buisson, D.; Alston, W.; Jiang, J.

2017-10-01

I will present results from the 1.5Ms XMM-Newton observing campaign on the most X-ray variable AGN, IRAS 13224-3809. We find a series of nine absorption lines with a velocity of 0.24c from an ultra-fast outflow. For the first time, we are able to see extremely rapid variability of the UFO features, and can link this to the X-ray variability from the inner accretion disk. We find a clear flux dependence of the outflow features, suggesting that the wind is ionized by increasing X-ray emission.

On the K-term and dispersion ratios of semi-regular variables

International Nuclear Information System (INIS)

Aslan, Z.

1981-01-01

Optical velocities of semi-regular (SR) and irregular (Lb) variables are analysed for a K-term. There is evidence for a dependence upon stellar period. Absorption lines in shorter period non-emission SR variables are blue-shifted relative to the centre-of-mass velocity by about 6 +- 3 km s -1 . Emission-line SR variables give a non-negative absorption K-term and Lb variables give no K-terms other than zero. Comparison is made with the K-terms implied by the OH velocity pattern in long-period variables. Dispersion ratios are also calculated. (author)

Systems and software variability management concepts, tools and experiences

CERN Document Server

Capilla, Rafael; Kang, Kyo-Chul

2013-01-01

The success of product line engineering techniques in the last 15 years has popularized the use of software variability as a key modeling approach for describing the commonality and variability of systems at all stages of the software lifecycle. Software product lines enable a family of products to share a common core platform, while allowing for product specific functionality being built on top of the platform. Many companies have exploited the concept of software product lines to increase the resources that focus on highly differentiating functionality and thus improve their competitiveness

Solar Spectral Irradiance Changes During Cycle 24

Science.gov (United States)

Marchenko, Sergey; Deland, Matthew

2014-01-01

We use solar spectra obtained by the Ozone Monitoring Instrument (OMI) on board the Aura satellite to detect and follow long-term (years) and short-term (weeks) changes in the solar spectral irradiance (SSI) in the 265-500 nm spectral range. During solar Cycle 24, in the relatively line-free regions the SSI changed by approximately 0.6% +/- 0.2% around 265 nm. These changes gradually diminish to 0.15% +/- 0.20% at 500 nm. All strong spectral lines and blends, with the notable exception of the upper Balmer lines, vary in unison with the solar "continuum." Besides the lines with strong chromospheric components, the most involved species include Fe I blends and all prominent CH, NH, and CN spectral bands. Following the general trend seen in the solar "continuum," the variability of spectral lines also decreases toward longer wavelengths. The long-term solar cycle SSI changes are closely, to within the quoted 0.1%-0.2% uncertainties, matched by the appropriately adjusted short-term SSI variations derived from the 27 day rotational modulation cycles. This further strengthens and broadens the prevailing notion about the general scalability of the UV SSI variability to the emissivity changes in the Mg II 280 nm doublet on timescales from weeks to years. We also detect subtle deviations from this general rule: the prominent spectral lines and blends at lambda approximately or greater than 350 nm show slightly more pronounced 27 day SSI changes when compared to the long-term (years) trends. We merge the solar data from Cycle 21 with the current Cycle 24 OMI and GOME-2 observations and provide normalized SSI variations for the 170-795 nm spectral region.

Electric field measurements from satellites-to-forbidden line ratios in an Omega-Upgrade laser-produced plasma. Semi-annual report, February 1--May 31, 1996

International Nuclear Information System (INIS)

Griem, H.R.; Elton, R.C.; Welch, B.L.

1996-01-01

Under this FY-96 NLUF program, the authors began their search for satellite lines to forbidden transitions for localized laser-induced electric field measurements by preparing in their laboratory a flat-field grazing incidence spectrograph for use on the OMEGA-Upgrade facility. This involved wavelength calibration using a (small) laser-produced plasma, as well as designing and constructing a mounting table compatible with the large 60-beam target chamber at LLE. Beginning in April 1996 they installed and aligned the spectrograph at LLE. Following final alignment on Monday, April 29, they obtained the following day their first time-integrated spectral data in the 30--250 angstrom range. A total of 28 successful shots were obtained. For most shots, two beams of the OMEGA-Upgrade laser were used at nominal uv-pulse widths of 1.1 ns and energies ranging from 76--470 J/beam, with focal spots of 80--450 microm and irradiances covering approximately 10 14 --10 16 Watt/cm 2 . Planar targets used consisted of Mg and NaF, as well as boron mounted on a plastic film, with some of the former two overcoated with 5 microm of CH on each side for containing the plasma, at least during the early portion of the pulse. Preliminary analyses indicate that they do indeed observe the desired Li-like L-shell spectra for oxygen, fluorine, sodium and magnesium, as well as L-shell lines in the corresponding H-(Balmer) and He-like species. Similarly, they recorded K-shell lines from B and C. Sample traces for Mg and Na fluoride from their soft x-ray spectrograph are shown. Both of these shots were obtained at a rather low applied irradiance of 2 X 10 14 W/cm 2 , and were chosen mainly for line identification. The parent Li-like 2s-3p allowed lines corresponding to the forbidden-line satellites sought for E-field determinations are clearly present. The calculated satellite line intensity relative to the intensity from this 2s-3p transition is ∼ 3%

A multi-frequency study of symbiotic stars: Pt. 1

International Nuclear Information System (INIS)

Ivison, R.J.; Bode, M.F.; Roberts, J.A.

1991-01-01

The relationship between optical line flux and 5 GHz radio flux is investigated for a sample of 17 northern sky symbiotic stars. Data were obtained near-simultaneously with the Manchester Echelle Spectrograph mounted on the Isaac Newton Telescope, La Palma and the Broad Band Interferometer at Jodrell Bank. Colour excesses, calculated from Balmer hydrogen line fluxes assuming Case B recombination ratios, are compared with other reddening estimates and also combined with extinction maps to provide improved distance estimates. Optical line fluxes are used in combination with radio fluxes to estimate physical parameters of these objects, including mass-loss rates. (author)

Spectral Monitoring of AGN: Preliminary Results for Ark 564 and Arp 102B

Directory of Open Access Journals (Sweden)

Shapovalova A. I.

2011-09-01

Full Text Available We present preliminary results of the long-term spectral monitoring of two active galactic nuclei with different broad line shapes: Ark 564 and Arp 102B. Ark 564 is a bright nearby narrow-line Syfert 1 (NLS1 galaxy with relatively narrow permitted optical emission lines and a high Fe II/Hβ ratio, while Arp 102B is a nearby broad-line radio galaxy with broad double-peaked Balmer emission lines. The spectra of Ark 564 were observed during 11-year period (1999-2009 and the spectra of Arp 102B in the 12-year period (1998-2009, with SAO 6 m and 1 m telescopes (Russia and the OAGH 2.1 m telescope (Cananea, Mexico.

Properties of Narrow line Seyfert 1 galaxies

Science.gov (United States)

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 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.

Optical plasma diagnostics

International Nuclear Information System (INIS)

Gross, B.

1973-01-01

The measurement is described of the radial courses of temperature and electron, atom and ion density in the plasma of a water-stabilized arc with currents from 20 A to 60 A. For temperature measurement a method based on the determination of the relative intensity of Balmer lines was used. The electron density was measured by determining the Hsub(β) line profile and the relative density of other particles was measured by determining the intensity ratio of radiation emitted by the respective atoms or ions. (author)

Line profile variations in selected Seyfert galaxies

International Nuclear Information System (INIS)

Kollatschny, W; Zetzl, M; Ulbrich, K

2010-01-01

Continua as well as the broad emission lines in Seyfert 1 galaxies vary in different galaxies with different amplitudes on typical timescales of days to years. We present the results of two independent variability campaigns taken with the Hobby-Eberly Telescope. We studied in detail the integrated line and continuum variations in the optical spectra of the narrow-line Seyfert galaxy Mrk 110 and the very broad-line Seyfert galaxy Mrk 926. The broad-line emitting region in Mrk 110 has radii of four to 33 light-days as a function of the ionization degree of the emission lines. The line-profile variations are matched by Keplerian disk models with some accretion disk wind. The broad-line region in Mrk 926 is very small showing an extension of two to three light-days only. We could detect a structure in the rms line-profiles as well as in the response of the line profile segments of Mrk 926 indicating the BLR is structured.

Genetic variability in local Brazilian horse lines using microsatellite markers.

Science.gov (United States)

Silva, A C M; Paiva, S R; Albuquerque, M S M; Egito, A A; Santos, S A; Lima, F C; Castro, S T; Mariante, A S; Correa, P S; McManus, C M

2012-04-10

Genetic variability at 11 microsatellite markers was analyzed in five naturalized/local Brazilian horse breeds or genetic groups. Blood samples were collected from 328 animals of the breeds Campeira (Santa Catarina State), Lavradeira (Roraima State), Pantaneira (Pantanal Mato-Grossense), Mangalarga Marchador (Minas Gerais State), as well as the genetic group Baixadeiro (Maranhão State), and the exotic breeds English Thoroughbred and Arab. We found significant genetic variability within evaluated microsatellite loci, with observed heterozygosis varying between 0.426 and 0.768 and polymorphism information content values of 0.751 to 0.914. All breeds showed high inbreeding coefficients and were not in Hardy-Weinberg equilibrium. The smallest genetic distance was seen between the Pantaneira and Arab breeds. The principal component analyzes and Bayesian approach demonstrated that the exotic breeds have had a significant influence on the genetic formation of the local breeds, with introgression of English Throroughbred in Pantaneira and Lavradeira, as well as genetic proximity between the Arab, Pantaneira and Mangalarga Marchador populations. This study shows the need to conserve traits acquired by naturalized horse breeds over centuries of natural selection in Brazil due to the genetic uniqueness of each group, suggesting a reduced gene flow between them. These results reinforce the need to include these herds in animal genetic resource conservation programs to maximize the genetic variability and conserve useful allele combinations.

Long-Term Monitoring of the Broad-Line Region Properties in a Selected Sample of AGN

Energy Technology Data Exchange (ETDEWEB)

Ilić, Dragana [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Belgrade (Serbia); Shapovalova, Alla I. [Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz (Russian Federation); Popović, Luka Č. [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Belgrade (Serbia); Astronomical Observatory, Belgrade (Serbia); Chavushyan, Vahram [Instituto Nacional de Astrofísica, Óptica y Electrónica, Puebla (Mexico); Burenkov, Alexander N. [Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz (Russian Federation); Kollatschny, Wolfram [Institut fuer Astrophysik, Universitaet Goettingen, Göttingen (Germany); Kovačević, Andjelka [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Belgrade (Serbia); Marčeta-Mandić, Sladjana [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Belgrade (Serbia); Astronomical Observatory, Belgrade (Serbia); Rakić, Nemanja [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Belgrade (Serbia); Faculty of Science, University of Banjaluka, Banjaluka, Republic of Srpska (Bosnia and Herzegovina); La Mura, Giovanni; Rafanelli, Piero, E-mail: dilic@math.rs [Department of Physics and Astronomy, University of Padova, Padova (Italy)

2017-09-14

We present the results of the long-term optical monitoring campaign of active galactic nuclei (AGN) coordinated by the Special Astrophysical Observatory of the Russian Academy of Science. This campaign has produced a remarkable set of optical spectra, since we have monitored for several decades different types of broad-line (type 1) AGN, from a Seyfert 1, double-peaked line, radio loud and radio quiet AGN, to a supermassive binary black hole candidate. Our analysis of the properties of the broad line region (BLR) of these objects is based on the variability of the broad emission lines. We hereby give a comparative review of the variability properties of the broad emission lines and the BLR of seven different type 1 AGNs, emphasizing some important results, such as the variability rate, the BLR geometry, and the presence of the intrinsic Baldwin effect. We are discussing the difference and similarity in the continuum and emission line variability, focusing on what is the impact of our results to the supermassive black hole mass determination from the BLR properties.

Long-Term Monitoring of the Broad-Line Region Properties in a Selected Sample of AGN

Directory of Open Access Journals (Sweden)

Dragana Ilić

2017-09-01

Full Text Available We present the results of the long-term optical monitoring campaign of active galactic nuclei (AGN coordinated by the Special Astrophysical Observatory of the Russian Academy of Science. This campaign has produced a remarkable set of optical spectra, since we have monitored for several decades different types of broad-line (type 1 AGN, from a Seyfert 1, double-peaked line, radio loud and radio quiet AGN, to a supermassive binary black hole candidate. Our analysis of the properties of the broad line region (BLR of these objects is based on the variability of the broad emission lines. We hereby give a comparative review of the variability properties of the broad emission lines and the BLR of seven different type 1 AGNs, emphasizing some important results, such as the variability rate, the BLR geometry, and the presence of the intrinsic Baldwin effect. We are discussing the difference and similarity in the continuum and emission line variability, focusing on what is the impact of our results to the supermassive black hole mass determination from the BLR properties.

THE LICK AGN MONITORING PROJECT: VELOCITY-DELAY MAPS FROM THE MAXIMUM-ENTROPY METHOD FOR Arp 151

International Nuclear Information System (INIS)

Bentz, Misty C.; Barth, Aaron J.; Walsh, Jonelle L.; Horne, Keith; Bennert, Vardha Nicola; Treu, Tommaso; Canalizo, Gabriela; Filippenko, Alexei V.; Gates, Elinor L.; Malkan, Matthew A.; Minezaki, Takeo; Woo, Jong-Hak

2010-01-01

We present velocity-delay maps for optical H I, He I, and He II recombination lines in Arp 151, recovered by fitting a reverberation model to spectrophotometric monitoring data using the maximum-entropy method. H I response is detected over the range 0-15 days, with the response confined within the virial envelope. The Balmer-line maps have similar morphologies but exhibit radial stratification, with progressively longer delays for Hγ to Hβ to Hα. The He I and He II response is confined within 1-2 days. There is a deficit of prompt response in the Balmer-line cores but strong prompt response in the red wings. Comparison with simple models identifies two classes that reproduce these features: free-falling gas and a half-illuminated disk with a hot spot at small radius on the receding lune. Symmetrically illuminated models with gas orbiting in an inclined disk or an isotropic distribution of randomly inclined circular orbits can reproduce the virial structure but not the observed asymmetry. Radial outflows are also largely ruled out by the observed asymmetry. A warped-disk geometry provides a physically plausible mechanism for the asymmetric illumination and hot spot features. Simple estimates show that a disk in the broad-line region of Arp 151 could be unstable to warping induced by radiation pressure. Our results demonstrate the potential power of detailed modeling combined with monitoring campaigns at higher cadence to characterize the gas kinematics and physical processes that give rise to the broad emission lines in active galactic nuclei.

MHC variability in heritage breeds of chickens.

Science.gov (United States)

Fulton, J E; Lund, A R; McCarron, A M; Pinegar, K N; Korver, D R; Classen, H L; Aggrey, S; Utterbach, C; Anthony, N B; Berres, M E

2016-02-01

The chicken Major Histocompatibility Complex (MHC) is very strongly associated with disease resistance and thus is a very important region of the chicken genome. Historically, MHC (B locus) has been identified by the use of serology with haplotype specific alloantisera. These antisera can be difficult to produce and frequently cross-react with multiple haplotypes and hence their application is generally limited to inbred and MHC-defined lines. As a consequence, very little information about MHC variability in heritage chicken breeds is available. DNA-based methods are now available for examining MHC variability in these previously uncharacterized populations. A high density SNP panel consisting of 101 SNP that span a 230,000 bp region of the chicken MHC was used to examine MHC variability in 17 heritage populations of chickens from five universities from Canada and the United States. The breeds included 6 heritage broiler lines, 3 Barred Plymouth Rock, 2 New Hampshire and one each of Rhode Island Red, Light Sussex, White Leghorn, Dark Brown Leghorn, and 2 synthetic lines. These heritage breeds contained from one to 11 haplotypes per line. A total of 52 unique MHC haplotypes were found with only 10 of them identical to serologically defined haplotypes. Furthermore, nine MHC recombinants with their respective parental haplotypes were identified. This survey confirms the value of these non-commercially utilized lines in maintaining genetic diversity. The identification of multiple MHC haplotypes and novel MHC recombinants indicates that diversity is being generated and maintained within these heritage populations. © 2016 Poultry Science Association Inc.

SPECTROSCOPIC VARIABILITY OF IRAS 22272+5435

International Nuclear Information System (INIS)

Začs, Laimons; Grankina, Aija; Musaev, Faig; Kaminsky, Bogdan; Pavlenko, Yakiv; Sperauskas, Julius; Hrivnak, Bruce J.

2016-01-01

A time series of high-resolution spectra was observed in the optical wavelength region for the bright proto-planetary nebula IRAS 22272+5435 (HD 235858), along with a simultaneous monitoring of its radial velocity and BV R C magnitudes. The object is known to vary in light, color, and velocity owing to pulsation with a period of 132 days. The light and color variations are accompanied by significant changes in spectral features, most of which are identified as lines of carbon-bearing molecules. According to the observations, the C 2 Swan system and CN Red system lines are stronger near the light minimum. A photospheric spectrum of the central star was calculated using new self-consistent atmospheric models. The observed intensity variations in the C 2 Swan system and CN Red system lines were found to be much larger than expected if due solely to the temperature variation in the atmosphere of the pulsating star. In addition, the molecular lines are blueshifted relative to the photospheric velocity. The site of formation of the strong molecular features appears to be a cool outflow triggered by the pulsation. The variability in atomic lines seems to be mostly due variations of the effective temperature during the pulsation cycle. The profiles of strong atomic lines are split, and some of them are variable in a timescale of a week or so, probably because of shock waves in the outer atmosphere

A fully discrete energy stable scheme for a phase filed moving contact line model with variable densities and viscosities

KAUST Repository

Zhu, Guangpu

2018-01-26

In this paper, a fully discrete scheme which considers temporal and spatial discretizations is presented for the coupled Cahn-Hilliard equation in conserved form with the dynamic contact line condition and the Navier-Stokes equation with the generalized Navier boundary condition. Variable densities and viscosities are incorporated in this model. A rigorous proof of energy stability is provided for the fully discrete scheme based on a semi-implicit temporal discretization and a finite difference method on the staggered grids for the spatial discretization. A splitting method based on the pressure stabilization is implemented to solve the Navier-Stokes equation, while the stabilization approach is also used for the Cahn-Hilliard equation. Numerical results in both 2-D and 3-D demonstrate the accuracy, efficiency and decaying property of discrete energy of the proposed scheme.

Early Photometric and Spectral Evolution of Nova Cygni 2014 (V2659 Cyg

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Burlak M. A.

2015-12-01

Full Text Available We present optical spectroscopic and UBV (RIC photometric observations of Nova Cygni 2014 (V2659 Cyg from its rebrightening to the nebular stage. After the first maximum, the nova underwent several irregular flare-like rebrightenings, with amplitudes up to two magnitudes, accompanied with spectral changes. During the bright state, forbidden lines became weaker; the absorption components of Balmer, He I, Fe II, N I, N II, O I lines strengthened, indicating an increase in the density and mass-loss rate in the form of a wind.

The Influence of Gas Composition in Dielectric Barrier Discharges on the Broadening of the Hydrogen Hα Transition

International Nuclear Information System (INIS)

Janus, H. W.

2006-01-01

The distribution of hydrogen atoms responsible for emission of the Balmer Hα line in the region of the dielectric barrier discharges in the helium and hydrogen as well as in the argon and hydrogen mixtures, in the direction perpendicular to the electrode surfaces, has bee determined by the optical emission spectroscopy accounting for the polarization of the emitted light. The procedure of fitting the measured line profiles accounting for the Stark effect has been used for determination of the distribution of the electric field in the discharge region

Studies of radioinduced mutations in sorghum grain: 1. Comparison of phenotypic variability obtained through hybridation and mutagenesis of F2 and M2 populations; 2. Agronomical and physiotechnical characterization of mutants lines in the original collection and in the advanced lines of the Chapingo Postgraduate college

International Nuclear Information System (INIS)

Parra Negrete, L.A.

1986-01-01

Genetic inprovement of cultivated plants consists essentially of three phases (1) generation of genetic variability (2) selection of genotypes and (3) evaluation of selected genotypes. Hybridization and spontaneous or induced mutations are, responsible for the generation of and increase in genetic vegetative variability. Accordingly, such methods are used alternatively in local programs for plant improvement either for introducing improved genotypes or as sources of germplasma. This thesis is based on two experiments of mutations induced by cobalt 60 ionizing radiation while using distinct materials and methods presented in two parts, the first section analyze the mutation variability and the second the evaluation of mutant lines. (author)

Frequency tracking and variable bandwidth for line noise filtering without a reference.

Science.gov (United States)

Kelly, John W; Collinger, Jennifer L; Degenhart, Alan D; Siewiorek, Daniel P; Smailagic, Asim; Wang, Wei

2011-01-01

This paper presents a method for filtering line noise using an adaptive noise canceling (ANC) technique. This method effectively eliminates the sinusoidal contamination while achieving a narrower bandwidth than typical notch filters and without relying on the availability of a noise reference signal as ANC methods normally do. A sinusoidal reference is instead digitally generated and the filter efficiently tracks the power line frequency, which drifts around a known value. The filter's learning rate is also automatically adjusted to achieve faster and more accurate convergence and to control the filter's bandwidth. In this paper the focus of the discussion and the data will be electrocorticographic (ECoG) neural signals, but the presented technique is applicable to other recordings.

Spectroscopic measurements of plasma emission light for plasma-based acceleration experiments

International Nuclear Information System (INIS)

Filippi, F.; Mostacci, A.; Palumbo, L.; Anania, M.P.; Biagioni, A.; Chiadroni, E.; Ferrario, M.; Cianchi, A.; Zigler, A.

2016-01-01

Advanced particle accelerators are based on the excitation of large amplitude plasma waves driven by either electron or laser beams. Future experiments scheduled at the SPARC-LAB test facility aim to demonstrate the acceleration of high brightness electron beams through the so-called resonant Plasma Wakefield Acceleration scheme in which a train of electron bunches (drivers) resonantly excites wakefields into a preformed hydrogen plasma; the last bunch (witness) injected at the proper accelerating phase gains energy from the wake. The quality of the accelerated beam depends strongly on plasma density and its distribution along the acceleration length. The measurements of plasma density of the order of 10 16 –10 17  cm −3 can be performed with spectroscopic measurements of the plasma-emitted light. The measured density distribution for hydrogen filled capillary discharge with both Balmer alpha and Balmer beta lines and shot-to-shot variation are here reported.

Spectroscopic measurements of plasma emission light for plasma-based acceleration experiments

Science.gov (United States)

Filippi, F.; Anania, M. P.; Biagioni, A.; Chiadroni, E.; Cianchi, A.; Ferrario, M.; Mostacci, A.; Palumbo, L.; Zigler, A.

2016-09-01

Advanced particle accelerators are based on the excitation of large amplitude plasma waves driven by either electron or laser beams. Future experiments scheduled at the SPARC_LAB test facility aim to demonstrate the acceleration of high brightness electron beams through the so-called resonant Plasma Wakefield Acceleration scheme in which a train of electron bunches (drivers) resonantly excites wakefields into a preformed hydrogen plasma; the last bunch (witness) injected at the proper accelerating phase gains energy from the wake. The quality of the accelerated beam depends strongly on plasma density and its distribution along the acceleration length. The measurements of plasma density of the order of 1016-1017 cm-3 can be performed with spectroscopic measurements of the plasma-emitted light. The measured density distribution for hydrogen filled capillary discharge with both Balmer alpha and Balmer beta lines and shot-to-shot variation are here reported.

Aspect-Oriented Model-Driven Software Product Line Engineering

Science.gov (United States)

Groher, Iris; Voelter, Markus

Software product line engineering aims to reduce development time, effort, cost, and complexity by taking advantage of the commonality within a portfolio of similar products. The effectiveness of a software product line approach directly depends on how well feature variability within the portfolio is implemented and managed throughout the development lifecycle, from early analysis through maintenance and evolution. This article presents an approach that facilitates variability implementation, management, and tracing by integrating model-driven and aspect-oriented software development. Features are separated in models and composed of aspect-oriented composition techniques on model level. Model transformations support the transition from problem to solution space models. Aspect-oriented techniques enable the explicit expression and modularization of variability on model, template, and code level. The presented concepts are illustrated with a case study of a home automation system.

Hearily reddened Hg-Mn star HD 29647

International Nuclear Information System (INIS)

Strajzhis, V.; Glagolevskij, Yu.V.; Romanyuk, I.I.; Bychkov, V.D.; AN SSSR, Nizhnij Arkhyz. Spetsial'naya Astrofizicheskaya Observatoriya)

1982-01-01

A heavily reddened HD 29647 (V=8sup(m).4) star is investigated using the 6-meter telescope spectrograms with dispersions 9 and 28 A/mm and photometric observations in the Vilnius seven- color system. Parameters Tsub(e)=15600 K (corresponding spectral type B5) and log g=3.70 from hydrogen lines and Balmer jump were obtained. HD 29647 is a peculiar star of the Hg-Mn type. The radial velocity of the star is+14.1+-1.0 km/s, almost identical with that of the dark Taurus cloud and its T Tauri-type variables. If the star is near the front edge of the dark cloud at the distance of 165 pc and has Esub(B-V)=1.06, its visual absolute magnitude is - 0sup(m).9. Photometric observations permit to suspect a slight varia bility in the U, P, and X colors [ru

Several real variables

CERN Document Server

Kantorovitz, Shmuel

2016-01-01

This undergraduate textbook is based on lectures given by the author on the differential and integral calculus of functions of several real variables. The book has a modern approach and includes topics such as: •The p-norms on vector space and their equivalence •The Weierstrass and Stone-Weierstrass approximation theorems •The differential as a linear functional; Jacobians, Hessians, and Taylor's theorem in several variables •The Implicit Function Theorem for a system of equations, proved via Banach’s Fixed Point Theorem •Applications to Ordinary Differential Equations •Line integrals and an introduction to surface integrals This book features numerous examples, detailed proofs, as well as exercises at the end of sections. Many of the exercises have detailed solutions, making the book suitable for self-study. Several Real Variables will be useful for undergraduate students in mathematics who have completed first courses in linear algebra and analysis of one real variable.

Line Width Recovery after Vectorization of Engineering Drawings

Directory of Open Access Journals (Sweden)

Gramblička Matúš

2016-12-01

Full Text Available Vectorization is the conversion process of a raster image representation into a vector representation. The contemporary commercial vectorization software applications do not provide sufficiently high quality outputs for such images as do mechanical engineering drawings. Line width preservation is one of the problems. There are applications which need to know the line width after vectorization because this line attribute carries the important semantic information for the next 3D model generation. This article describes the algorithm that is able to recover line width of individual lines in the vectorized engineering drawings. Two approaches are proposed, one examines the line width at three points, whereas the second uses a variable number of points depending on the line length. The algorithm is tested on real mechanical engineering drawings.

The polarization of NGC 1068

International Nuclear Information System (INIS)

Bailey, Jeremy; Axon, D.J.; Hough, J.H.; Heathcote, S.R.

1988-01-01

Broad-band polarimetry of NGC 1068 over the wavelength range 0.36-4.8μm is presented, together with high-resolution spectropolarimetry of the Hβ, [O III] and Hα, [N II] regions of the spectrum. We recognize several different polarization components and conclude that they can all be accounted for by processes involving dust. Optical continuum polarization and broad features associated with the Balmer emission lines are due to scattering into the line of sight, of radiation from an obscured Seyfert I nucleus. We argue that the scattering is probably by dust in the narrow line region, but cannot exclude the possibility of electron scattering. (author)

Spectroscopic measurements of an H- ion source discharge

International Nuclear Information System (INIS)

Keller, R.; Smith, H.V. Jr.

1985-01-01

Spectral emission lines from an H - Penning surface-plasma source (SPS), the 4X source, are examined in the visible and near ultraviolet. Electron distribution temperatures are deduced from integral line-strength measurements. These temperatures are surprisingly low, about 0.5 eV. Electron density values of about 1.5 x 10 14 cm -3 and H-atom energies between 2 and 2.6 eV are determined from the measured Balmer-line profiles. Assuming the H - energy is identical to the H-atom energy, an emittance limit of 0.006 π x cm x mrad is deduced for this source with a 5.4-mm aperture

Transgenic Chinese hamster V79 cell lines which exhibit variable levels of gpt mutagenesis

International Nuclear Information System (INIS)

Klein, C.B.; Rossman, T.G.

1990-01-01

The Escherichia coli gpt gene coding for xanthine-guanine phosphoribosyl transferase has been stably transfected into HPRT - Chinese hamster V79 cells. Several gpt - cell lines have been established, which retain the sequence(s) even after long-term culture without selection for gpt. While spontaneous mutagenesis to gpt - occurs rather frequently for most cell lines, it cannot be correlated with either the number of plasmid integration sites or deletion of the plasmid sequence(s). One transgenic cell line (g12), which continuously maintains a low spontaneous mutation frequency was used in comparative mutagenesis studies with wild-type V79 cells (gpt vs. hprt). Alkylating agents such as N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and β-propiolactone (BPL) are shown to be equally toxic and mutagenic in both g12 and V79 cells. UV and X-rays are also equally toxic to both cell lines. The data presented here suggests that g12 cells may be useful to study mammalian mutagenesis by agents which yield limited response at the hprt locus

Observations of chromospheric lines from OSO-8

Science.gov (United States)

Grossmann-Doerth, U.; Kneer, F.; Uexkuell, M.; Artzner, G. E.; Vial, J. C.

1980-01-01

Results of OSO-8 measurements of the line profiles of the solar Lyman alpha, Ca II K and Mg II k lines are presented. Observations were obtained with the Laboratoire de Physique Stellaire et Planetaire spectrometer at spectral resolutions of 0.25 and 0.060 A for Lyman alpha and 0.025 A for the Mg II and Ca II lines. The Lyman alpha profiles are found to be highly variable according to spatial position with the intensities of the three lines well correlated, and confirm previous observations of the quiet solar chromosphere. Data suggest that the quiet chromosphere is a dynamical phenomenon whose description in terms of a static model atmosphere is only qualitatively valid at best.

Acquisition of data from on-line laser turbidimeter and calculation of some kinetic variables in computer-coupled automated fed-batch culture

International Nuclear Information System (INIS)

Kadotani, Y.; Miyamoto, K.; Mishima, N.; Kominami, M.; Yamane, T.

1995-01-01

Output signals of a commercially available on-line laser turbidimeter exhibit fluctuations due to air and/or CO 2 bubbles. A simple data processing algorithm and a personal computer software have been developed to smooth the noisy turbidity data acquired, and to utilize them for the on-line calculations of some kinetic variables involved in batch and fed-batch cultures of uniformly dispersed microorganisms. With this software, about 10 3 instantaneous turbidity data acquired over 55 s are averaged and convert it to dry cell concentration, X, every minute. Also, volume of the culture broth, V, is estimated from the averaged output data of weight loss of feed solution reservoir, W, using an electronic balance on which the reservoir is placed. Then, the computer software is used to perform linear regression analyses over the past 30 min of the total biomass, VX, the natural logarithm of the total biomass, ln(VX), and the weight loss, W, in order to calculate volumetric growth rate, d(VX)/dt, specific growth rate, μ [ = dln(VX)/dt] and the rate of W, dW/dt, every minute in a fed-batch culture. The software used to perform the first-order regression analyses of VX, ln(VX) and W was applied to batch or fed-batch cultures of Escherichia coli on minimum synthetic or natural complex media. Sample determination coefficients of the three different variables (VX, ln(VX) and W) were close to unity, indicating that the calculations are accurate. Furthermore, growth yield, Y x/s , and specific substrate consumption rate, q sc , were approximately estimated from the data, dW/dt and in a ‘balanced’ fed-batch culture of E. coli on the minimum synthetic medium where the computer-aided substrate-feeding system automatically matches well with the cell growth. (author)

Harmonic content in the variable-frequency ac power line of TFTR

International Nuclear Information System (INIS)

Zabar, Z.; Bronner, G.; McMurray, S.; Karady, G.

1979-12-01

Studies were made of the harmonic content of the current and voltage at the generator bus of the Tokamak Fusion Test Reactor. Out of numerous load scenarios, one case was considered in detail. The harmonics were found acceptable for the generator; however, control problems and substantial telecommunications interference may result, requiring appropriate control measures and shielded telecommunication lines

Photometric and spectroscopic variability of the B5IIIe star HD 171219

Science.gov (United States)

Andrade, L.; Janot-Pacheco, E.; Emilio, M.; Frémat, Y.; Neiner, C.; Poretti, E.; Mathias, P.; Rainer, M.; Suárez, J. C.; Uytterhoeven, K.; Briquet, M.; Diago, P. D.; Fabregat, J.; Gutiérrez-Soto, J.

2017-07-01

We analyzed the star HD 171219, one of the relatively bright Be stars observed in the seismo field of the CoRoT satellite, in order to determine its physical and pulsation characteristics. Classical Be stars are main-sequence objects of mainly B-type, whose spectra show, or have shown at some epoch, Balmer lines in emission and an infrared excess. Both characteristics are attributed to an equatorially concentrated circumstellar disk fed by non-periodic mass-loss episodes (outbursts). Be stars often show nonradial pulsation gravity modes and, as more recently discovered, stochastically excited oscillations. Applying the CLEANEST algorithm to the high-cadence and highly photometrically precise measurements of the HD 171219 light curve led us to perform an unprecedented detailed analysis of its nonradial pulsations. Tens of frequencies have been detected in the object compatible with nonradial g-modes. Additional high-resolution ground-based spectroscopic observations were obtained at La Silla (HARPS) and Haute Provence (SOPHIE) observatories during the month preceding CoRoT observations. Additional information was obtained from low-resolution spectra from the BeSS database. From spectral line fitting we determined physical parameters of the star, which is seen equator-on (I = 90°). We also found in the ground data the same frequencies as in CoRoT data. Additionally, we analyzed the circumstellar activity through the traditional method of violet to red emission Hα line variation. A quintuplet was identified at approximately 1.113 c d-1 (12.88 μHz) with a separation of 0.017 c d-1 that can be attributed to a pulsation degree ℓ 2. The light curve shows six small- to medium-scale outbursts during the CoRoT observations. The intensity of the main frequencies varies after each outburst, suggesting a possible correlation between the nonradial pulsations regime and the feeding of the envelope. The CoRoT space mission was developed and operated by the French space agency

Finite Element Based Response Surface Methodology to Optimize Segmental Tunnel Lining

Directory of Open Access Journals (Sweden)

A. Rastbood

2017-04-01

Full Text Available The main objective of this paper is to optimize the geometrical and engineering characteristics of concrete segments of tunnel lining using Finite Element (FE based Response Surface Methodology (RSM. Input data for RSM statistical analysis were obtained using FEM. In RSM analysis, thickness (t and elasticity modulus of concrete segments (E, tunnel height (H, horizontal to vertical stress ratio (K and position of key segment in tunnel lining ring (θ were considered as input independent variables. Maximum values of Mises and Tresca stresses and tunnel ring displacement (UMAX were set as responses. Analysis of variance (ANOVA was carried out to investigate the influence of each input variable on the responses. Second-order polynomial equations in terms of influencing input variables were obtained for each response. It was found that elasticity modulus and key segment position variables were not included in yield stresses and ring displacement equations, and only tunnel height and stress ratio variables were included in ring displacement equation. Finally optimization analysis of tunnel lining ring was performed. Due to absence of elasticity modulus and key segment position variables in equations, their values were kept to average level and other variables were floated in related ranges. Response parameters were set to minimum. It was concluded that to obtain optimum values for responses, ring thickness and tunnel height must be near to their maximum and minimum values, respectively and ground state must be similar to hydrostatic conditions.

Metrology of variable-line-spacing x-ray gratings using the APS Long Trace Profiler

Science.gov (United States)

Sheung, Janet; Qian, Jun; Sullivan, Joseph; Thomasset, Muriel; Manton, Jonathan; Bean, Sunil; Takacs, Peter; Dvorak, Joseph; Assoufid, Lahsen

2017-09-01

As resolving power targets have increased with each generation of beamlines commissioned in synchrotron radiation facilities worldwide, diffraction gratings are quickly becoming crucial optical components for meeting performance targets. However, the metrology of variable-line-spacing (VLS) gratings for high resolution beamlines is not widespread; in particular, no metrology facility at any US DOE facility is currently equipped to fully characterize such gratings. To begin to address this issue, the Optics Group at the Advanced Photon Source at Argonne, in collaboration with SOLEIL and with support from Brookhaven National Laboratory (BNL), has developed an alternative beam path addition to the Long Trace Profiler (LTP) at Argonne's Advanced Photon Source. This significantly expands the functionality of the LTP not only to measure mirrors surface slope profile at normal incidence, but also to characterize the groove density of VLS diffraction gratings in the Littrow incidence up to 79°, which covers virtually all diffraction gratings used at synchrotrons in the first order. The LTP light source is a 20mW HeNe laser, which yields enough signal for diffraction measurements to be performed on low angle blazed gratings optimized for soft X-ray wavelengths. We will present the design of the beam path, technical requirements for the optomechanics, and our data analysis procedure. Finally, we discuss challenges still to be overcome and potential limitations with use of the LTP to perform metrology on diffraction gratings.

Consumo de pornografía on-line y off-line en adolescentes colombianos

Directory of Open Access Journals (Sweden)

Reynaldo Rivera

2016-01-01

Full Text Available El consumo de medios de comunicación se ha incrementado notablemente en los últimos años. Una consecuencia no deseada de ello es la proliferación de consumos de riesgo, como es el caso de la pornografía on-line y off-line. Aunque la literatura ha señalado una serie de variables predictoras (edad, género, etnia, nivel socioeconómico o estructura familiar, estudios recientes han sugerido incluir los valores y los estilos de vida como factores asociados a las decisiones de consumo. El objetivo del presente trabajo fue examinar si los estilos de vida relacionales de los adolescentes son predictores relevantes del consumo de pornografía tanto en Internet como en revistas o vídeos. Se empleó un diseño observacional transversal que incluyó una muestra representativa de 9.942 adolescentes colombianos (Medad=14,93, DT=2,47. Los estilos de vida, controlando el efecto de variables sociodemográficas, estructurales e individuales, fueron sometidos a un análisis de regresión múltiple y a un análisis de mediación. Los resultados indicaron que el estilo intrafamiliar positivo estuvo asociado con una reducción en el consumo de pornografía, sin embargo, tanto el estilo intrafamiliar negativo como el de independencia relacional incrementan el mismo. Además se propone que los estilos relacionales familiares pueden mediar la relación entre los valores positivos y el comportamiento de riesgo on-line y off-line. Finalmente, se realiza una discusión de los resultados desde la perspectiva relacional y su aplicación en programas de educación mediática.

Sustainable evolution of product line infrastructure code

OpenAIRE

Patzke, T.

2011-01-01

A major goal in many software development organizations today is to reduce development effort and cost, while improving their products' quality and diversity by developing reusable software. An organization takes advantage of its products' similarities, exploits what they have in common and manages what varies among them by building a product line infrastructure. A product line infrastructure is a reuse repository that contains exactly those common and variable artifacts, such as requirements...

Matrix elements and transition probabilities of interaction of electromagnetic field with a hydrogen-like atom

International Nuclear Information System (INIS)

Rajput, B.S.

1977-01-01

Using the reduced expansions of second quantized electromagnetic vector potential operator in terms of irreducible representations of Pioncare group in the interaction Hamiltonian, the exact matrix elements of interaction of electromagnetic field with a hydrogenic atom have been derived and the contributions of transitions for different combinations of angular momentum quantum numbers to the transition probabilities of various lines in Lyman-, Balmer-, and Paschen-series have been computed. (author)

Feasibility of a fast optical pressure interlock for the ITER neutral beam injectors

International Nuclear Information System (INIS)

Ash, Andrew; Surrey, Elizabeth

2009-01-01

The feasibility of using Balmer-α emission for a high-speed pressure diagnostic and beam interlock for the ITER neutral beam heating system is investigated. An interlock is needed to prevent excessive re-ionisation of the neutral beam when rapid excursions of pressure occur in either the electrostatic residual ion dump (ERID), or the neutral beam duct (NBD). The re-ionised fraction of the beam, will be deflected by stray tokamak fields, potentially causing excessive thermal loads on beam line components. Experience from JET indicates that a response time of order 100 μs is required in order to prevent fast pressure excursions. Fast penning gauges have a time response of around 30-50 ms, however, a faster response (around 1 μs) is possible by monitoring the H α (656.3 nm)/D α (656.1 nm) emission from collisional excitation of the background gas and neutral beam. Published total cross-sections are used to calculate a signal of 3.5x10 13 -3.0x10 17 photons s -1 m -2 sr -1 for normal conditions. This signal must be distinguished from the background light of the tokamak plasma (line emission and bremsstrahlung). The beam emission is Doppler shifted by up to 21 nm (D operation) and up to 27 nm (H operation) depending on angle of observation and this can be used to help distinguish against background line emission. The distribution of background light along the beam line is calculated with a two-dimensional radiosity code, solving the equilibrium energy balance within the beam line enclosure. The Balmer-α signal and background signal due to bremsstrahlung are compared for a 500-MW reference plasma.

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

Science.gov (United States)

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.

Variability of ethane on Jupiter

Science.gov (United States)

Kostiuk, Theodor; Espenak, Fred; Mumma, Michael J.; Deming, Drake; Zipoy, David

1987-01-01

Varying stratospheric temperature profiles and C2H6 altitude distributions furnish contexts for the evaluation of ethane abundances and distributions in the Jupiter stratosphere. Substantial ethane line emission and retrieved mole fraction variability is noted near the footprint of Io's flux tube, as well as within the auroral regions. It is suggested that this and other observed phenomena are due to the modification of local stratospheric chemistry by higher-order effects, which are in turn speculated to be due to the precipitation of charged particles along magnetic field lines.

Revealing the ultrafast outflow in IRAS 13224-3809 through spectral variability

Science.gov (United States)

Parker, M. L.; Alston, W. N.; Buisson, D. J. K.; Fabian, A. C.; Jiang, J.; Kara, E.; Lohfink, A.; Pinto, C.; Reynolds, C. S.

2017-08-01

We present an analysis of the long-term X-ray variability of the extreme narrow-line Seyfert 1 galaxy IRAS 13224-3809 using principal component analysis (PCA) and fractional excess variability (Fvar) spectra to identify model-independent spectral components. We identify a series of variability peaks in both the first PCA component and Fvar spectrum which correspond to the strongest predicted absorption lines from the ultrafast outflow (UFO) discovered by Parker et al. (2017). We also find higher order PCA components, which correspond to variability of the soft excess and reflection features. The subtle differences between RMS and PCA results argue that the observed flux-dependence of the absorption is due to increased ionization of the gas, rather than changes in column density or covering fraction. This result demonstrates that we can detect outflows from variability alone and that variability studies of UFOs are an extremely promising avenue for future research.

Static third-harmonic lines in widely variable fiber continuum generation

Science.gov (United States)

Tu, Haohua; Zhao, Youbo; Liu, Yuan; Boppart, Stephen A.

2014-01-01

An intriguing phenomenon of third-harmonic generation under fiber continuum generation is the emission of an anharmonic signal. One popular interpretation of this effect has developed into a general theory of fiber third-harmonic generation. Here we produce "static" third-harmonic lines dictated fully by fiber properties independent of pump parameters, in contrast to the signals of all known phase-matched nonlinear optical processes that vary dynamically with these parameters. We argue that the anharmonic signal is an illusion of the continuum generation, that it is in fact harmonic, and that this theory should be reevaluated.

Short-term radio variability and parsec-scale structure in A gamma-ray narrow-line Seyfert 1 galaxy 1H 0323+342

Energy Technology Data Exchange (ETDEWEB)

Wajima, Kiyoaki [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Xuhui District, Shanghai 200030 (China); Fujisawa, Kenta [The Research Institute for Time Studies, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi 753-8511 (Japan); Hayashida, Masaaki [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan); Isobe, Naoki [The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Ishida, Takafumi [Graduate School of Science and Engineering, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi 753-8512 (Japan); Yonekura, Yoshinori, E-mail: kwajima@shao.ac.cn [Center for Astronomy, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512 (Japan)

2014-02-01

We made simultaneous single-dish and very long baseline interferometer (VLBI) observations of a narrow-line Seyfert 1 galaxy 1H 323+342, showing gamma-ray activity revealed by Fermi/Large Area Telescope observations. We found significant variation of the total flux density at 8 GHz on the timescale of one month by the single-dish monitoring. The total flux density varied by 5.5% in 32 days, which is comparable to the gamma-ray variability timescale, corresponding to the variability brightness temperature of 7.0 × 10{sup 11} K. The source consists of central and southeastern components on the parsec (pc) scale. Only the flux of the central component decreased in the same way as the total flux density, indicating that the short-term radio variability, and probably the gamma-ray-emitting region, is associated with this component. From the VLBI observations, we obtained brightness temperatures of greater than (5.2 ± 0.3) × 10{sup 10} K and derived an equipartition Doppler factor of greater than 1.7, a variability Doppler factor of 2.2, and an 8 GHz radio power of 10{sup 24.6} W Hz{sup –1}. Combining them, we conclude that acceleration of radio jets and creation of high-energy particles are ongoing in the central engine and that the apparent very radio-loud feature of the source is due to the Doppler boosting effect, resulting in the intrinsic radio loudness being an order of magnitude smaller than the observed values. We also conclude that the pc-scale jet represents recurrent activity from the spectral fitting and the estimated kinematic age of pc- and kpc-scale extended components with different position angles.

Theory of extended stellar atmospheres. II. A grid of static spherical models for O stars and planetary nebula nuclei

International Nuclear Information System (INIS)

Kunasz, P.B.; Hummer, D.G.; Mihalas, D.

1975-01-01

Spherical static non-LTE model atmospheres are presented for stars with M/M/sub sun/=30 and 60 at various points on their evolutionary tracks, and for some nuclei of planetary nebulae at two points of a modified Harman-Seaton sequence. The method of Mihalas and Hummer was employed, which uses a parametrized radiation force multiplier to simulate the force of radiation arising from the entire line spectrum. However, in the present work the density structure computed in the LTE models was held fixed in the calculation of the corresponding non-LTE models; in addition, the opacity of an ''average light ion'' was taken into account. The temperatures for the non-LTE models are generally lower, at a given depth, than for the corresponding LTE models when T/sub eff/<45,000 K, while the situation is reversed at higher temperatures. The continuous energy distributions are generally flattened by extension. The Lyman jump is in emission for extended models of massive stars, but never for the models of nuclei of planetary nebulae (this is primarily a temperature effect). The Balmer jumps are always in absorption. The Lyman lines are in emission, and the Balmer lines in absorption; He ii lambda4686 comes into emission in the most extended models without hydrogen line pumping, showing that it is an indicator of atmospheric extension. Very severe limb darkening is found for extended models, which have apparent angular sized significantly smaller than expected from the geometrical size of the star. Extensive tables are given of monochromatic magnitudes, continuum jumps and gradients, Stomgren-system colors, monochromatic extensions, and the profiles and equivalent widths of the hydrogen lines for all models, and of the He ii lines for some of the 60 M/sub X/ models

The optical spectrum and morphology of the probable X-ray galaxy NGC 5506 (3U 1410-03)

International Nuclear Information System (INIS)

Wilson, A.S.; Penston, M.V.; Fosbury, R.A.E.; Boksenberg, A.

1976-01-01

Spectra of the nucleus and plates of the galaxy NGC 5506, suggested by Bahcall et al. as the identification of the X-ray source 3U 1410-03, have been obtained with the Isaac Newton and Anglo-Australian Telescopes. The photographs show it to be a highly elongated system, crossed by dust lanes and possessing a prominent nucleus. It appears to be of irregular Type II and superficially resembles M 82. The nuclear spectrum is dominated by intense emission lines of [O III], [O I], [N II], [S II] and the Balmer series. Lines of high ionized species (e.g. He II, [Ne V], [Fe VII]) are also found, implying that the object is active and greatly enhancing the probability of association with the X-ray source. Numerous weak lines of [Fe II] emission are observed. The strong lines are narrower than is characteristic of Seyfert galaxies, and have widths (FWHM) of about 400 km s -1 . The measured Balmer decrement indicates the nucleus is significantly reddened, from which a visual absorption Asub(v) approximately equal to 4.5 mag is deduced. The dereddened line intensities are remarkably similar to those derived for the radio galaxy Cyg A by Osterbrock and Miller. The forbidden lines from NGC 5506 are emitted in a region with log 10 Tsub(e) =4.2 and log 10 Nsub(e) = 3.4. The observed continuum may be described by a power law S varies as νsup(+α) with α = - 3.6 +- 0.5; after correction for reddening the spectral index becomes α = - 1.3 +- 0.6. If the X-ray source is associated with the nucleus, the high visual absorption implies a low energy cut-off in its spectrum near 0.9 keV. (author)

Introducing Product Lines through Open Source Tools

OpenAIRE

Haugen, Øystein

2008-01-01

We present an approach to introducing product lines to companies that lower their initial risk by applying open source tools and a smooth learning curve into the use and creation of domain specific modeling combined with standardized variability modeling.

ELLERMAN BOMBS AT HIGH RESOLUTION. IV. VISIBILITY IN Na I AND Mg I

Energy Technology Data Exchange (ETDEWEB)

Rutten, R. J.; Rouppe van der Voort, L. H. M.; Vissers, G. J. M., E-mail: R.J.Rutten@uu.nl [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, N-0315 Oslo (Norway)

2015-08-01

Ellerman bombs are transient brightenings of the wings of the solar Balmer lines that mark reconnection in the photosphere. Ellerman noted in 1917 that he did not observe such brightenings in the Na i D and Mg i b lines. This non-visibility should constrain EB interpretation, but has not been addressed in published bomb modeling. We therefore test Ellerman’s observation and confirm it using high-quality imaging spectrometry with the Swedish 1-m Solar Telescope. However, we find a diffuse brightness in these lines that seems to result from prior EBs. We tentatively suggest this is a post-bomb hot-cloud phenomenon also found in recent EB spectroscopy in the ultraviolet.

Intra lines uniformity and inter lines variation of rice mutants resulting from irradiation of South Kalimantan local varieties

International Nuclear Information System (INIS)

Raihani Wahdah; Gusti Rumayadi; Rahmi Zulhidiani

2016-01-01

The preference of farmer in tidal swamp on local rice varieties are quite high, but local varieties have a long life and low yield characters, so it needs to be improved for the trait. This study is part of activities of the local rice varieties improvement to generate promising lines were short-moderate aged, but the slimming and pera (high amylose content) grains maintained. The aims of this study were to determine the intra lines uniformity and the inter lines variation of M5 generation of rice mutant lines. The experiment was carried out in the Experimental Station of Agriculture Faculty, Lambung Mangkurat University from March to September 2014. The experiment used 150 earliest flowering lines of 300 M5 mutant lines that were planted. Intra lines uniformity were analysed by comparing the variance of each mutant lines with variance of its parent, while the variation among lines were analyzed by comparing the variance of all lines with variance of its parent. More than 85 % M5 mutant lines from Siam Harli as parent and > 79 % of Siam Kuatek as parent are uniform. The uniform character at all M5 mutant lines, both of Siam Harli or Siam Kuatek parent are the harvest age, the filled grains number, and the empty grains number. There is no variability between M5 mutant lines, but some of M5 mutant lines from Siam Harli and Siam Kuatek have some better characters than their parents, so there is an opportunity for selection. (author)

Line outage contingency analysis including the system islanding scenario

Energy Technology Data Exchange (ETDEWEB)

Hazarika, D.; Bhuyan, S. [Assam Engineering College, Jalukbari, Guwahati 781013 (India); Chowdhury, S.P. [Jadavpur University, Jadavpur, Kolkata 700 032 (India)

2006-05-15

The paper describes an algorithm for determining the line outage contingency of a line taking into account of line over load effect in remaining lines and subsequent tripping of over loaded line(s) leading to possible system split or islanding of a power system. The optimally ordered sparse [B'], [B'] matrices for the integrated system are used for load flow analysis to determine modified values of voltage phase angles [{delta}] and bus voltages [V] to determine the over loading effect on the remaining lines due to outage of a selected line outage contingency. In case of over loading in remaining line(s), the over loaded lines are removed from the system and a topology processor is used to find the islands. A fast decoupled load flow (FDLF) analysis is carried out for finding out the system variables for the islanded (or single island) system by incorporating appropriate modification in the [B'] and [B'] matrices of the integrated system. Line outage indices based on line overload, loss of load, loss of generation and static voltage stability are computed to indicate severity of a line outage of a selected line. (author)

Variables associated with lung congestion as assessed by chest ultrasound in diabetics undergoing hemodialysis

Directory of Open Access Journals (Sweden)

Paulo Roberto Santos

Full Text Available Abstract Introduction: Ultrasound is an emerging method for assessing lung congestion but is still seldom used. Lung congestion is an important risk of cardiac events and death in end-stage renal disease (ESRD patients on hemodialysis (HD. Objective: We investigated possible variables associated with lung congestion among diabetics with ESRD on HD, using chest ultrasound to detect extracellular lung water. Methods: We studied 73 patients with diabetes as the primary cause of ESRD, undergoing regular HD. Lung congestion was assessed by counting the number of B lines detected by chest ultrasound. Hydration status was assessed by bioimpedance analysis and cardiac function by echocardiography. The collapse index of the inferior vena cava (IVC was measured by ultrasonography. All patients were classified according to NYHA score. Correlations of the number of B lines with continuous variables and comparisons regarding the number of B lines according to categorical variables were performed. Multivariate linear regression was used to test the variables as independent predictors of the number of B lines. Results: None of the variables related to hydration status and cardiac function were associated with the number of B lines. In the multivariate analysis, only the IVC collapse index (b = 45.038; p < 0.001 and NYHA classes (b = 13.995; p = 0.006 were independent predictors of the number of B lines. Conclusion: Clinical evaluation based on NYHA score and measurement of the collapsed IVC index were found to be more reliable than bioimpedance analysis to predict lung congestion.

Flare activity on UV CETI: visible and IUE observations

International Nuclear Information System (INIS)

Phillips, K.J.H.; Bromage, G.E.; Dufton, P.L.; Keenan, F.P.; Kingston, A.E.

1988-06-01

Simultaneous far-ultraviolet (IUE) spectroscopy and optical photometry and spectrophotometry of a flare on UV Ceti are reported. The flare reached ΔU = 2sup(m) but showed only modest enhancements in the IUE spectra. The optical spectrophotometry indicated broadened Balmer line profiles during the flare, with Hβ and Hγ clearly showing red wings. The results are compared with other IUE and optical observations of UV Ceti, and their solar analogues. (author)

FIRST LONG-TERM OPTICAL SPECTRAL MONITORING OF A BINARY BLACK HOLE CANDIDATE E1821+643. I. VARIABILITY OF SPECTRAL LINES AND CONTINUUM

International Nuclear Information System (INIS)

Shapovalova, A. I.; Burenkov, A. N.; Zhdanova, V. E.; Popović, L. Č.; Chavushyan, V. H.; Valdés, J. R.; Patiño-Álvarez, V.; León-Tavares, J.; Torrealba, J.; Ilić, D.; Kovačević, A.; Kollatschny, W.

2016-01-01

We report the results of the first long-term (1990–2014) optical spectrophotometric monitoring of a binary black hole candidate QSO E1821+643, a low-redshift, high-luminosity, radio-quiet quasar. In the monitored period, the continua and Hγ fluxes changed about two times, while the Hβ flux changed about 1.4 times. We found periodical variations in the photometric flux with periods of 1200, 1850, and 4000 days, and 4500-day periodicity in the spectroscopic variations. However, the periodicity of 4000–4500 days covers only one cycle of variation and should be confirmed with a longer monitoring campaign. There is an indication of the period around 1300 days in the spectroscopic light curves, buts with small significance level, while the 1850-day period could not be clearly identified in the spectroscopic light curves. The line profiles have not significantly changed, showing an important red asymmetry and broad line peak redshifted around +1000 km s −1 . However, Hβ shows a broader mean profile and has a larger time lag (τ ∼ 120 days) than Hγ (τ ∼ 60 days). We estimate that the mass of the black hole is ∼2.6 × 10 9 M ⊙ . The obtained results are discussed in the frame of the binary black hole hypothesis. To explain the periodicity in the flux variability and high redshift of the broad lines, we discuss a scenario where dense, gas-rich, cloudy-like structures are orbiting around a recoiling black hole

First International Workshop on Variability in Software Architecture (VARSA 2011)

NARCIS (Netherlands)

Galster, Matthias; Avgeriou, Paris; Weyns, Danny; Mannisto, Tomi

2011-01-01

Variability is the ability of a software artifact to be changed for a specific context. Mechanisms to accommodate variability include software product lines, configuration wizards and tools in commercial software, configuration interfaces of software components, or the dynamic runtime composition of

The nature of the companion star in Circinus X-1

Science.gov (United States)

Johnston, Helen M.; Soria, Roberto; Gibson, Joel

2016-02-01

We present optical spectra and images of the X-ray binary Circinus X-1. The optical light curve of Cir X-1 is strongly variable, changing in brightness by 1.2 mag in the space of four days. The shape of the light curve is consistent with that seen in the 1980s, when the X-ray and radio counterparts of the source were at least ten times as bright as they are currently. We detect strong, variable H α emission lines, consisting of multiple components which vary with orbital phase. We estimate the extinction to the source from the strength of the diffuse interstellar bands and the Balmer decrement; the two methods give AV = 7.6 ± 0.6 mag and AV > 9.1 mag, respectively. The optical light curve can be modelled as arising from irradiation of the companion star by the central X-ray source, where a low-temperature star fills its Roche lobe in an orbit of moderate eccentricity (e ˜ 0.4). We suggest that the companion star is overluminous and underdense, due to the impact of the supernova which occurred less than 5000 yr ago.

An efficient scheme for a phase field model for the moving contact line problem with variable density and viscosity

KAUST Repository

Gao, Min

2014-09-01

In this paper, we develop an efficient numerical method for the two phase moving contact line problem with variable density, viscosity, and slip length. The physical model is based on a phase field approach, which consists of a coupled system of the Cahn-Hilliard and Navier-Stokes equations with the generalized Navier boundary condition [1,2,5]. To overcome the difficulties due to large density and viscosity ratio, the Navier-Stokes equations are solved by a splitting method based on a pressure Poisson equation [11], while the Cahn-Hilliard equation is solved by a convex splitting method. We show that the method is stable under certain conditions. The linearized schemes are easy to implement and introduce only mild CFL time constraint. Numerical tests are carried out to verify the accuracy, stability and efficiency of the schemes. The method allows us to simulate the interface problems with extremely small interface thickness. Three dimensional simulations are included to validate the efficiency of the method. © 2014 Elsevier Inc.

An efficient scheme for a phase field model for the moving contact line problem with variable density and viscosity

KAUST Repository

Gao, Min; Wang, Xiao-Ping

2014-01-01

In this paper, we develop an efficient numerical method for the two phase moving contact line problem with variable density, viscosity, and slip length. The physical model is based on a phase field approach, which consists of a coupled system of the Cahn-Hilliard and Navier-Stokes equations with the generalized Navier boundary condition [1,2,5]. To overcome the difficulties due to large density and viscosity ratio, the Navier-Stokes equations are solved by a splitting method based on a pressure Poisson equation [11], while the Cahn-Hilliard equation is solved by a convex splitting method. We show that the method is stable under certain conditions. The linearized schemes are easy to implement and introduce only mild CFL time constraint. Numerical tests are carried out to verify the accuracy, stability and efficiency of the schemes. The method allows us to simulate the interface problems with extremely small interface thickness. Three dimensional simulations are included to validate the efficiency of the method. © 2014 Elsevier Inc.

Photospheric Ca and Mg line-strength variations in G29-38

International Nuclear Information System (INIS)

Hippel, Ted von; Thompson, Susan E; Reach, W T; Mullally, F; Kilic, Mukremin; Nitta, Atsuko

2009-01-01

Temporal variations in metal-line strengths in H-atmosphere white dwarfs hold the potential to test the timescales of gravitational settling theory. These short timescales, in turn, require that DAZs are currently accreting. Such temporal variations would also indicate that accretion from a circumstellar dust disk can be episodic. We are compiling increasing evidence for time-variable Ca and Mg line-strength variations in the best studied DAZ, G29-38. Our evidence to date supports the gravitational settling timescales of Koester and Wilken (2006) and episodic accretion from G29-38's debris disk. Furthermore, we have detected evidence for time-variable accretion with a timescale = 24 hours, and typical variability of ∼4% during the 100 days of our autumn 2007 monitoring campaign.

Photospheric Ca and Mg line-strength variations in G29-38

Energy Technology Data Exchange (ETDEWEB)

Hippel, Ted von [Physics Department, Siena College, Loudonville, NY (United States); Thompson, Susan E [Department of Physics and Astronomy, University of Delaware, Newark, DE (United States); Reach, W T [IPAC, California Institute of Technology, Pasadena, CA (United States); Mullally, F [Department of Astronomy, Princeton University, Princeton, NJ (United States); Kilic, Mukremin [Center for Astrophysics, Harvard University, Cambridge, MA (United States); Nitta, Atsuko, E-mail: tvonhippel@siena.ed, E-mail: sthomp@physics.udel.ed, E-mail: reach@ipac.caltech.ed, E-mail: fergal@astro.princeton.ed, E-mail: kilic@astronomy.ohio-state.ed, E-mail: anitta@gemini.ed [Gemini Observatory, Hilo, HI (United States)

2009-06-01

Temporal variations in metal-line strengths in H-atmosphere white dwarfs hold the potential to test the timescales of gravitational settling theory. These short timescales, in turn, require that DAZs are currently accreting. Such temporal variations would also indicate that accretion from a circumstellar dust disk can be episodic. We are compiling increasing evidence for time-variable Ca and Mg line-strength variations in the best studied DAZ, G29-38. Our evidence to date supports the gravitational settling timescales of Koester and Wilken (2006) and episodic accretion from G29-38's debris disk. Furthermore, we have detected evidence for time-variable accretion with a timescale = 24 hours, and typical variability of approx4% during the 100 days of our autumn 2007 monitoring campaign.

Product Lines for Service Oriented Applications - PL for SOA

Directory of Open Access Journals (Sweden)

Maurice H. ter Beek

2011-08-01

Full Text Available PL for SOA proposes, formally, a software engineering methodology, development techniques and support tools for the provision of service product lines. We propose rigorous modeling techniques for the specification and verification of formal notations and languages for service computing with inclinations of variability. Through these cutting-edge technologies, increased levels of flexibility and adaptivity can be achieved. This will involve developing semantics of variability over behavioural models of services. Such tools will assist organizations to plan, optimize and control the quality of software service provision, both at design and at run time by making it possible to develop flexible and cost-effective software systems that support high levels of reuse. We tackle this challenge from two levels. We use feature modeling from product line engineering and, from a services point of view, the orchestration language Orc. We introduce the Smart Grid as the service product line to apply the techniques to.

Characterizing chemical systems with on-line computers and graphics

International Nuclear Information System (INIS)

Frazer, J.W.; Rigdon, L.P.; Brand, H.R.; Pomernacki, C.L.

1979-01-01

Incorporating computers and graphics on-line to chemical experiments and processes opens up new opportunities for the study and control of complex systems. Systems having many variables can be characterized even when the variable interactions are nonlinear, and the system cannot a priori be represented by numerical methods and models. That is, large sets of accurate data can be rapidly acquired, then modeling and graphic techniques can be used to obtain partial interpretation plus design of further experimentation. The experimenter can thus comparatively quickly iterate between experimentation and modeling to obtain a final solution. We have designed and characterized a versatile computer-controlled apparatus for chemical research, which incorporates on-line instrumentation and graphics. It can be used to determine the mechanism of enzyme-induced reactions or to optimize analytical methods. The apparatus can also be operated as a pilot plant to design control strategies. On-line graphics were used to display conventional plots used by biochemists and three-dimensional response-surface plots

Pulse timing for cataclysmic variables

International Nuclear Information System (INIS)

Chester, T.J.

1979-01-01

It is shown that present pulse timing measurements of cataclysmic variables can be explained by models of accretion disks in these systems, and thus such measurements can constrain disk models. The model for DQ Her correctly predicts the amplitude variation of the continuum pulsation and can also perhaps explain the asymmetric amplitude of the pulsed lambda4686 emission line. Several other predictions can be made from the model. In particular, if pulse timing measurements that resolve emission lines both in wavelength and in binary phase can be made, the projected orbital radius of the white dwarf could be deduced

Spectral Classification of MASTER J174041.78+272632.4

Science.gov (United States)

Silverman, J. M.; Cohen, D. P.; Filippenko, A. V.

2012-06-01

We report that inspection of a CCD spectrum (range 340-1000 nm), obtained on June 27.4 UT with the Shane 3-m reflector (+ Kast spectrograph) at Lick Observatory, shows that MASTER J174041.78+272632.4 (ATel #4213) is a Galactic variable star. Hydrogen Balmer absorption superposed with weak, narrow emission is detected at redshift 0. The spectrum roughly resembles that of a B[e] star.

Variable stator radial turbine

Science.gov (United States)

Rogo, C.; Hajek, T.; Chen, A. G.

1984-01-01

A radial turbine stage with a variable area nozzle was investigated. A high work capacity turbine design with a known high performance base was modified to accept a fixed vane stagger angle moveable sidewall nozzle. The nozzle area was varied by moving the forward and rearward sidewalls. Diffusing and accelerating rotor inlet ramps were evaluated in combinations with hub and shroud rotor exit rings. Performance of contoured sidewalls and the location of the sidewall split line with respect to the rotor inlet was compared to the baseline. Performance and rotor exit survey data are presented for 31 different geometries. Detail survey data at the nozzle exit are given in contour plot format for five configurations. A data base is provided for a variable geometry concept that is a viable alternative to the more common pivoted vane variable geometry radial turbine.

Poverty Lines Based on Fuzzy Sets Theory and Its Application to Malaysian Data

Science.gov (United States)

Abdullah, Lazim

2011-01-01

Defining the poverty line has been acknowledged as being highly variable by the majority of published literature. Despite long discussions and successes, poverty line has a number of problems due to its arbitrary nature. This paper proposes three measurements of poverty lines using membership functions based on fuzzy set theory. The three…

Supporting Development of Satellite's Guidance Navigation and Control Software: A Product Line Approach

Science.gov (United States)

McComas, David; Stark, Michael; Leake, Stephen; White, Michael; Morisio, Maurizio; Travassos, Guilherme H.; Powers, Edward I. (Technical Monitor)

2000-01-01

The NASA Goddard Space Flight Center Flight Software Branch (FSB) is developing a Guidance, Navigation, and Control (GNC) Flight Software (FSW) product line. The demand for increasingly more complex flight software in less time while maintaining the same level of quality has motivated us to look for better FSW development strategies. The GNC FSW product line has been planned to address the core GNC FSW functionality very similar on many recent low/near Earth missions in the last ten years. Unfortunately these missions have not accomplished significant drops in development cost since a systematic approach towards reuse has not been adopted. In addition, new demands are continually being placed upon the FSW which means the FSB must become more adept at providing GNC FSW functionality's core so it can accommodate additional requirements. These domain features together with engineering concepts are influencing the specification, description and evaluation of FSW product line. Domain engineering is the foundation for emerging product line software development approaches. A product line is 'A family of products designed to take advantage of their common aspects and predicted variabilities'. In our product line approach, domain engineering includes the engineering activities needed to produce reusable artifacts for a domain. Application engineering refers to developing an application in the domain starting from reusable artifacts. The focus of this paper is regarding the software process, lessons learned and on how the GNC FSW product line manages variability. Existing domain engineering approaches do not enforce any specific notation for domain analysis or commonality and variability analysis. Usually, natural language text is the preferred tool. The advantage is the flexibility and adapt ability of natural language. However, one has to be ready to accept also its well-known drawbacks, such as ambiguity, inconsistency, and contradictions. While most domain analysis

Low-frequency photospheric and wind variability in the early-B supergiant HD 2905

Science.gov (United States)

Simón-Díaz, S.; Aerts, C.; Urbaneja, M. A.; Camacho, I.; Antoci, V.; Fredslund Andersen, M.; Grundahl, F.; Pallé, P. L.

2018-04-01

Context. Despite important advances in space asteroseismology during the last decade, the early phases of evolution of stars with masses above 15 M⊙ (including the O stars and their evolved descendants, the B supergiants) have been only vaguely explored up to now. This is due to the lack of adequate observations for a proper characterization of the complex spectroscopic and photometric variability occurring in these stars. Aim. Our goal is to detect, analyze, and interpret variability in the early-B-type supergiant HD 2905 (κ Cas, B1 Ia) using long-term, ground-based, high-resolution spectroscopy. Methods: We gather a total of 1141 high-resolution spectra covering some 2900 days with three different high-performance spectrographs attached to 1-2.6m telescopes at the Canary Islands observatories. We complement these observations with the hipparcos light curve, which includes 160 data points obtained during a time span of 1200 days. We investigate spectroscopic variability of up to 12 diagnostic lines by using the zero and first moments of the line profiles. We perform a frequency analysis of both the spectroscopic and photometric dataset using Scargle periodograms. We obtain single snapshot and time-dependent information about the stellar parameters and abundances by means of the FASTWIND stellar atmosphere code. Results: HD 2905 is a spectroscopic variable with peak-to-peak amplitudes in the zero and first moments of the photospheric lines of up to 15% and 30 km s-1, respectively. The amplitude of the line-profile variability is correlated with the line formation depth in the photosphere and wind. All investigated lines present complex temporal behavior indicative of multi-periodic variability with timescales of a few days to several weeks. No short-period (hourly) variations are detected. The Scargle periodograms of the hipparcos light curve and the first moment of purely photospheric lines reveal a low-frequency amplitude excess and a clear dominant frequency

Negative employee corporate brand identification: A case study of a prominent Malaysian University corporate brand

OpenAIRE

Syed alwi, SF; Balmer, JMT; CheHa, N; Yen, D

2014-01-01

The purpose of this paper is to investigate negative employee corporate brand identification towards a business school in Malaysia. The research marshals the nascent literature of corporate brand identification (Balmer and Liao 2007; Balmer, Liao and Wang 2008) which marked new ground by drawing on social identity theory in corporate branding contexts. Corporate brand identification is relatively new concept but has been recognized as very important facet of corporate marketing (Balmer and Li...

Cubic systems with invariant affine straight lines of total parallel multiplicity seven

Directory of Open Access Journals (Sweden)

Alexandru Suba

2013-12-01

Full Text Available In this article, we study the planar cubic differential systems with invariant affine straight lines of total parallel multiplicity seven. We classify these system according to their geometric properties encoded in the configurations of invariant straight lines. We show that there are only 17 different topological phase portraits in the Poincar\\'e disc associated to this family of cubic systems up to a reversal of the sense of their orbits, and we provide representatives of every class modulo an affine change of variables and rescaling of the time variable.

Importance of representing optical depth variability for estimates of global line-shaped contrail radiative forcing.

Science.gov (United States)

Kärcher, Bernd; Burkhardt, Ulrike; Ponater, Michael; Frömming, Christine

2010-11-09

Estimates of the global radiative forcing by line-shaped contrails differ mainly due to the large uncertainty in contrail optical depth. Most contrails are optically thin so that their radiative forcing is roughly proportional to their optical depth and increases with contrail coverage. In recent assessments, the best estimate of mean contrail radiative forcing was significantly reduced, because global climate model simulations pointed at lower optical depth values than earlier studies. We revise these estimates by comparing the probability distribution of contrail optical depth diagnosed with a climate model with the distribution derived from a microphysical, cloud-scale model constrained by satellite observations over the United States. By assuming that the optical depth distribution from the cloud model is more realistic than that from the climate model, and by taking the difference between the observed and simulated optical depth over the United States as globally representative, we quantify uncertainties in the climate model's diagnostic contrail parameterization. Revising the climate model results accordingly increases the global mean radiative forcing estimate for line-shaped contrails by a factor of 3.3, from 3.5 mW/m(2) to 11.6 mW/m(2) for the year 1992. Furthermore, the satellite observations and the cloud model point at higher global mean optical depth of detectable contrails than often assumed in radiative transfer (off-line) studies. Therefore, we correct estimates of contrail radiative forcing from off-line studies as well. We suggest that the global net radiative forcing of line-shaped persistent contrails is in the range 8-20 mW/m(2) for the air traffic in the year 2000.

Radio molecular maser line study of symbiotic stars

International Nuclear Information System (INIS)

Cohen, N.L.; Ghigo, F.D.

1980-01-01

A sample of symbiotic stars has been searched for maser emission from the 1665- and 1667-MHz OH mainlines, the 22-GHz H 2 O line, and the 43-GHz SiO line. R Aqr remains the sole symbiotic for which maser emission has been detected. Its SiO spectrum reveals a pedestal of emission with a narrow superposed peak at V/sub LSR/ -26.4 +- 0.7 km/s. The line's existence and the pedestal feature are both characteristic of SiO lines found in late-type variables by Snyder et al. [Astrophys. J. 224, 512 (1978)]. For the other symbiotic stars, it is possible that conditions favorable for maser emission have been suppressed by the presence of a hot companion. Alternatively our findings may argue against the presence of late-type variables in symbiotic stars. In either case, R Aqr seems to be in a class by itself. We cannot confirm the suggestion that R Aqr is a binary, since the spectral feature has not shifted noticeably in the two years since the observations by Lepine, LeSqueren, and Scalise [Astrophys. J. 225, 869 (1978)]. However, we point out that monitoring the pedestal emission over a number of years is the least ambiguous way to discern any velocity shift that might result from orbital motion

The variable stars of NGC 1866

International Nuclear Information System (INIS)

Welch, D.L.; Cote, P.; Fischer, P.; Mateo, M.; Madore, B.F.

1991-01-01

A search has been conducted for new variables in the LMC cluster NGC 1866 using new multiepoch CCD photometry. Eight previously unknown Cepheid variables, most near the cluster core, are found. Of the new variables reported by Storm et al. (188), only six of 10 appear to be Cepheids and one of these is not a member. Periods and mean magnitudes and colors for sufficiently uncrowded variables are reported, as is one red giant variable of long period and one Cepheid which is a single-lined spectroscopic binary with a velocity semiamplitude greater than or equal to 10.5 km/s. The variation of light-curve amplitude with position in the instability strip is reported along with an apparently nonvariable star, which is a radial velocity member, in the strip. A true distance modulus of 18.57 + or - 0.01 mag is obtained for the cluster. 36 refs

Using principal component analysis to understand the variability of PDS 456

Science.gov (United States)

Parker, M. L.; Reeves, J. N.; Matzeu, G. A.; Buisson, D. J. K.; Fabian, A. C.

2018-02-01

We present a spectral-variability analysis of the low-redshift quasar PDS 456 using principal component analysis. In the XMM-Newton data, we find a strong peak in the first principal component at the energy of the Fe absorption line from the highly blueshifted outflow. This indicates that the absorption feature is more variable than the continuum, and that it is responding to the continuum. We find qualitatively different behaviour in the Suzaku data, which is dominated by changes in the column density of neutral absorption. In this case, we find no evidence of the absorption produced by the highly ionized gas being correlated with this variability. Additionally, we perform simulations of the source variability, and demonstrate that PCA can trivially distinguish between outflow variability correlated, anticorrelated and un-correlated with the continuum flux. Here, the observed anticorrelation between the absorption line equivalent width and the continuum flux may be due to the ionization of the wind responding to the continuum. Finally, we compare our results with those found in the narrow-line Seyfert 1 IRAS 13224-3809. We find that the Fe K UFO feature is sharper and more prominent in PDS 456, but that it lacks the lower energy features from lighter elements found in IRAS 13224-3809, presumably due to differences in ionization.

SHOCKED POSTSTARBUST GALAXY SURVEY. I. CANDIDATE POST-STARBUST GALAXIES WITH EMISSION LINE RATIOS CONSISTENT WITH SHOCKS

Energy Technology Data Exchange (ETDEWEB)

Alatalo, Katherine; Rich, Jeffrey A. [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Cales, Sabrina L. [Yale Center for Astronomy and Astrophysics, Physics Department, Yale University, New Haven, CT 06511 (United States); Appleton, Philip N.; Lanz, Lauranne [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Kewley, Lisa J.; Medling, Anne M. [Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston ACT 2611 (Australia); Lacy, Mark; Nyland, Kristina, E-mail: kalatalo@carnegiescience.edu [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)

2016-06-01

There are many mechanisms by which galaxies can transform from blue, star-forming spirals, to red, quiescent early-type galaxies, but our current census of them does not form a complete picture. Recent observations of nearby case studies have identified a population of galaxies that quench “quietly.” Traditional poststarburst searches seem to catch galaxies only after they have quenched and transformed, and thus miss any objects with additional ionization mechanisms exciting the remaining gas. The Shocked POststarburst Galaxy Survey (SPOGS) aims to identify transforming galaxies, in which the nebular lines are excited via shocks instead of through star formation processes. Utilizing the Oh-Sarzi-Schawinski-Yi (OSSY) measurements on the Sloan Digital Sky Survey Data Release 7 catalog, we applied Balmer absorption and shock boundary criteria to identify 1067 SPOG candidates (SPOGs*) within z = 0.2. SPOGs* represent 0.2% of the OSSY sample galaxies that exceed the continuum signal-to-noise cut (and 0.7% of the emission line galaxy sample). SPOGs* colors suggest that they are in an earlier phase of transition than OSSY galaxies that meet an “E+A” selection. SPOGs* have a 13% 1.4 GHz detection rate from the Faint Images of the Radio Sky at Twenty Centimeters Survey, higher than most other subsamples, and comparable only to low-ionization nuclear emission line region hosts, suggestive of the presence of active galactic nuclei (AGNs). SPOGs* also have stronger Na i D absorption than predicted from the stellar population, suggestive of cool gas being driven out in galactic winds. It appears that SPOGs* represent an earlier phase in galaxy transformation than traditionally selected poststarburst galaxies, and that a large proportion of SPOGs* also have properties consistent with disruption of their interstellar media, a key component to galaxy transformation. It is likely that many of the known pathways to transformation undergo a SPOG phase. Studying this sample of

Quiescent Galaxies in the 3D-HST Survey: Spectroscopic Confirmation of a Large Number of Galaxies with Relatively Old Stellar Populations at z ~ 2

Science.gov (United States)

Whitaker, Katherine E.; van Dokkum, Pieter G.; Brammer, Gabriel; Momcheva, Ivelina G.; Skelton, Rosalind; Franx, Marijn; Kriek, Mariska; Labbé, Ivo; Fumagalli, Mattia; Lundgren, Britt F.; Nelson, Erica J.; Patel, Shannon G.; Rix, Hans-Walter

2013-06-01

Quiescent galaxies at z ~ 2 have been identified in large numbers based on rest-frame colors, but only a small number of these galaxies have been spectroscopically confirmed to show that their rest-frame optical spectra show either strong Balmer or metal absorption lines. Here, we median stack the rest-frame optical spectra for 171 photometrically quiescent galaxies at 1.4 < z < 2.2 from the 3D-HST grism survey. In addition to Hβ (λ4861 Å), we unambiguously identify metal absorption lines in the stacked spectrum, including the G band (λ4304 Å), Mg I (λ5175 Å), and Na I (λ5894 Å). This finding demonstrates that galaxies with relatively old stellar populations already existed when the universe was ~3 Gyr old, and that rest-frame color selection techniques can efficiently select them. We find an average age of 1.3^{+0.1}_{-0.3} Gyr when fitting a simple stellar population to the entire stack. We confirm our previous result from medium-band photometry that the stellar age varies with the colors of quiescent galaxies: the reddest 80% of galaxies are dominated by metal lines and have a relatively old mean age of 1.6^{+0.5}_{-0.4} Gyr, whereas the bluest (and brightest) galaxies have strong Balmer lines and a spectroscopic age of 0.9^{+0.2}_{-0.1} Gyr. Although the spectrum is dominated by an evolved stellar population, we also find [O III] and Hβ emission. Interestingly, this emission is more centrally concentrated than the continuum with {L_{{O}\\,\\scriptsize{III}}}=1.7+/- 0.3\\times 10^{40} erg s-1, indicating residual central star formation or nuclear activity.

Spectrophotometry of RS Oph during the nebular phase

International Nuclear Information System (INIS)

Bohigas, J.; Echevarria, J.; Diego, F.; Sarmiento, J.A.

1989-01-01

Blue-wavelength spectroscopic observations of RS Oph, 201 day after the 1985 outburst are presented. An analysis of the TiO bands indicates a spectral type M4III for the secondary and a distance of 2 kpc to the system. The system of forbidden lines is excited by a shock wave, whereas Balmer emission is mainly produced by photoionization. The source of photons is probably residual thermonuclear burning occurring at the surface of the white dwarf. (author)

MASTER OT J014638.27+041324.4 is a Young Type IIP Supernova

Science.gov (United States)

Zheng, W.; Kelly, P. L.; Clubb, K. I.; Filippenko, A. V.

2013-12-01

We report that a CCD spectrum (range 350-1000 nm) of MASTER OT J014638.27+041324.4 (Shurpakov et al., ATel #5630) was obtained on Dec 6.5 UT with the Shane 3-m reflector (+Kast spectrograph) at Lick Observatory. The spectrum shows a blue continuum and weak, broad hydrogen Balmer lines having P-Cyg profiles, indicating that the object is a young Type IIP supernova. Weak He I 587.6 nm is also present.

Flare activity on UV Ceti: visible and IUE observations

International Nuclear Information System (INIS)

Phillips, K.J.H.; Bromage, G.E.; Dufton, P.L.; Keenan, F.P.; Kingston, A.E.

1988-01-01

Simultaneous far-ultraviolet (IUE) spectroscopy and optical photometry and spectrophotometry of a flare on UV Ceti are reported. The flare reached ΔU=2 mag but showed only modest enhancements in the IUE spectra. The optical spectrophotometry indicated broadened Balmer line profiles during the flare, with Hβ and Hγ clearly showing red wings (∼ 100 km s -1 ). The results are compared with other IUE and optical observations of UV Ceti, and their solar analogues. (author)

A congestion line flow control in deregulated power system

Directory of Open Access Journals (Sweden)

Venkatarajan Shanmuga Sundaram

2011-01-01

Full Text Available Under open access, market-driven transactions have become the new independent decision variables defining the behavior of the power system. The possibility of transmission lines getting over-loaded is relatively more under deregulated operation because different parts of the system are owned by separate companies and in part operated under varying service charges. This paper discusses a two-tier algorithm for correcting the lone overloads in conjunction with the conventional power-flow methods. The method uses line flow sensitivities, which are computed by the East Decoupled Power-flow algorithm and can be adapted for on-line implementation.

Variable Work Hours--The MONY Experience

Science.gov (United States)

Fields, Cynthia J.

1974-01-01

An experiment with variable work hours in one department of a large company was so successful that it has become standard procedure in various corporate areas, both staff and line. The result? Increased production, fewer errors, improved employee morale, and a significant reduction in lateness and absenteeism. (Author)

Luminosity and Redshift dependence of quasar spectral properties

Energy Technology Data Exchange (ETDEWEB)

Daniel E. Vanden Berk et al.

2004-03-09

Using a large sample of quasar spectra from the SDSS, we examine the composite spectral trends of quasars as functions of both redshift and luminosity, independently of one another. Aside from the well known Baldwin effect (BE)--the decrease of line equivalent width with luminosity--the average spectral properties are remarkably similar. Host galaxy contamination and the BE are the primary causes for apparent changes in the average spectral slope of the quasars. The BE is detected for most emission lines, including the Balmer lines, but with several exceptions including NV1240A. Emission line shifts of several lines are associated with the BE. The BE is mainly a function of luminosity, but also partly a function of redshift in that line equivalent widths become stronger with redshift. Some of the complex iron features change with redshift, particularly near the small blue bump region.

HDE 323771: a new Herbig Ae star

International Nuclear Information System (INIS)

Persi, P.; Polcaro, V.F.; Viotti, R.

1991-01-01

From an analysis of the blue and red spectrum, and a study of the energy distribution from the optical up to the far infrared, we identify HDE 323771 as a new PMS Herbig Ae star. The P Cygni line profiles observed in the Balmer and Fe II lines indicate the presence of a stellar wind with a velocity of about 250-350 km s -1 . An upper limit of mass loss rate is derived from the observed upper limit for the Br γ luminosity. The near-IR images and the IR energy distribution indicate the presence of an extended circumstellar dust envelope with a temperature of about 1500 K. (author)

2DCOS and PCMW2D analysis of FT-IR/ATR spectra measured at variable temperatures on-line to a polyurethane polymerization

Science.gov (United States)

Schuchardt, Patrick; Unger, Miriam; Siesler, Heinz W.

2018-01-01

In the present communication the potential of 2DCOS analysis and the spin-off technique perturbation-correlation moving window 2D (PCMW2D) analysis is illustrated with reference to spectroscopic changes observed in a data set recorded by in-line fiber-coupled FT-IR spectroscopy in the attenuated total reflection (ATR) mode during a polyurethane solution polymerization at different temperatures. In view of the chemical functionalities involved, hydrogen bonding plays an important role in this polymerization reaction. Based on the 2DCOS and PCMW2D analysis, the sequence of hydrogen bonding changes accompanying the progress of polymerization and precipitation of solid polymer can be determined. Complementary to the kinetic data derived from the original variable-temperature spectra in a previous publication the results provide a more detailed picture of the investigated solution polymerization.

Long time scale hard X-ray variability in Seyfert 1 galaxies

Science.gov (United States)

Markowitz, Alex Gary

This dissertation examines the relationship between long-term X-ray variability characteristics, black hole mass, and luminosity of Seyfert 1 Active Galactic Nuclei. High dynamic range power spectral density functions (PSDs) have been constructed for six Seyfert 1 galaxies. These PSDs show "breaks" or characteristic time scales, typically on the order of a few days. There is resemblance to PSDs of lower-mass Galactic X-ray binaries (XRBs), with the ratios of putative black hole masses and variability time scales approximately the same (106--7) between the two classes of objects. The data are consistent with a linear correlation between Seyfert PSD break time scale and black hole mass estimate; the relation extrapolates reasonably well over 6--7 orders of magnitude to XRBs. All of this strengthens the case for a physical similarity between Seyfert galaxies and XRBs. The first six years of RXTE monitoring of Seyfert 1s have been systematically analyzed to probe hard X-ray variability on multiple time scales in a total of 19 Seyfert is in an expansion of the survey of Markowitz & Edelson (2001). Correlations between variability amplitude, luminosity, and black hole mass are explored, the data support the model of PSD movement with black hole mass suggested by the PSD survey. All of the continuum variability results are consistent with relatively more massive black holes hosting larger X-ray emission regions, resulting in 'slower' observed variability. Nearly all sources in the sample exhibit stronger variability towards softer energies, consistent with softening as they brighten. Direct time-resolved spectral fitting has been performed on continuous RXTE monitoring of seven Seyfert is to study long-term spectral variability and Fe Kalpha variability characteristics. The Fe Kalpha line displays a wide range of behavior but varies less strongly than the broadband continuum. Overall, however, there is no strong evidence for correlated variability between the line and

The IFUSP microtron accelerator beam transport line

International Nuclear Information System (INIS)

Rios, Paulo Beolchi

2002-01-01

In this work, the electron optical project of the IFUSP microtron beam transport line is presented, including the operational values for the parameters of the dipolar and quadrupolar electromagnets, as well as their location along the beam line. Analytical calculations and computer simulations were performed to obtain these results, and a programming tool was developed in order to analyze the beam parameters and to help studying racetrack microtrons. The electron optical simulations were split into two different study cases: the microtron booster, and the transfer line. In the first case, it was determined the main operational parameters of a microtron working far from its usual stability conditions. In the latter, it was done the basic design of the linking line between the booster and main (not yet built) microtrons, and between them and the experimental hall, with a total path length of approximately 32 m including large horizontal and vertical deflections with variable beam energy. (author)

Radiation sensitivity of human lung cancer cell lines

International Nuclear Information System (INIS)

Carmichael, J.; Degraff, W.G.; Gamson, J.; Russo, G.; Mitchell, J.B.; Gazdar, A.F.; Minna, J.D.; Levitt, M.L.

1989-01-01

X-Ray survival curves were determined using a panel of 17 human lung cancer cell lines, with emphasis on non-small cell lung cancer (NSCLC). In contrast to classic small cell lung cancer (SCLC) cell lines, NSCLC cell lines were generally less sensitive to radiation as evidenced by higher radiation survival curve extrapolation numbers, surviving fraction values following a 2Gy dose (SF2) and the mean inactivation dose values (D) values. The spectrum of in vitro radiation responses observed was similar to that expected in clinical practice, although mesothelioma was unexpectedly sensitive in vitro. Differences in radiosensitivity were best distinguished by comparison of SF2 values. Some NSCLC lines were relatively sensitive, and in view of this demonstrable variability in radiation sensitivity, the SF2 value may be useful for in vitro predictive assay testing of clinical specimens. (author)

Spectral Variability of Quasar SDSS J030639.57+000343.1 ...

Indian Academy of Sciences (India)

variability of emission lines and continuum luminosity. In this paper, we present the results of SDSS J030639.57 +000343.1. We found a strong anticorrelation between the continuum luminosity at 5100 Å and the spec- tral index, implying a bluer-when-brighter trend. The luminosity of the broad Hα line is in proportion to the ...

Variable Permanent Magnet Quadrupole

International Nuclear Information System (INIS)

Mihara, T.; Iwashita, Y.; Kyoto U.; Kumada, M.; NIRS, Chiba; Spencer, C.M.; SLAC

2007-01-01

A permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens in a linear collider. An over 120 T/m strong variable permanent magnet quadrupole is achieved by the introduction of saturated iron and a 'double ring structure'. A fabricated PMQ achieved 24 T integrated gradient with 20 mm bore diameter, 100 mm magnet diameter and 20 cm pole length. The strength of the PMQ is adjustable in 1.4 T steps, due to its 'double ring structure': the PMQ is split into two nested rings; the outer ring is sliced along the beam line into four parts and is rotated to change the strength. This paper describes the variable PMQ from fabrication to recent adjustments

Subwavelength grating enabled on-chip ultra-compact optical true time delay line.

Science.gov (United States)

Wang, Junjia; Ashrafi, Reza; Adams, Rhys; Glesk, Ivan; Gasulla, Ivana; Capmany, José; Chen, Lawrence R

2016-07-26

An optical true time delay line (OTTDL) is a basic photonic building block that enables many microwave photonic and optical processing operations. The conventional design for an integrated OTTDL that is based on spatial diversity uses a length-variable waveguide array to create the optical time delays, which can introduce complexities in the integrated circuit design. Here we report the first ever demonstration of an integrated index-variable OTTDL that exploits spatial diversity in an equal length waveguide array. The approach uses subwavelength grating waveguides in silicon-on-insulator (SOI), which enables the realization of OTTDLs having a simple geometry and that occupy a compact chip area. Moreover, compared to conventional wavelength-variable delay lines with a few THz operation bandwidth, our index-variable OTTDL has an extremely broad operation bandwidth practically exceeding several tens of THz, which supports operation for various input optical signals with broad ranges of central wavelength and bandwidth.

Soft X-ray variability and the covering fraction of active galactic nuclei

International Nuclear Information System (INIS)

Wachter, K.W.; Strauss, M.A.; Filippenko, A.V.

1988-01-01

A model to explain the observed soft X-ray variability to some low-luminosity Seyfert 1 galaxies is developed. The variability is due to changes in the covering fraction of the central source as broad-line clouds move across our line of sight. A formalism is developed which is used to demonstrate how analysis of a soft X-ray light curve can provide three important quantities: the radius of the X-ray emitting region, the radius of a typical broad-line cloud, and the electron density in the cloud. It is shown that the results are rather insensitive to the assumed radial dependence of the surface brightness of the source, but are quite sensitive to a large dispersion in cloud sizes. 55 references

Problems due to icing of overhead lines - Part II

International Nuclear Information System (INIS)

Havard, D.G.; Pon, C.J.; Krishnasamy, S.G.

1985-01-01

A companion paper describes uncertainties in overhead line design due to the variability of ice and wind loads. This paper reviews two other effects due to icing; conductor galloping and torsional instability, which require further study. (author)

On-line optimal control improves gas processing

International Nuclear Information System (INIS)

Berkowitz, P.N.; Papadopoulos, M.N.

1992-01-01

This paper reports that the authors' companies jointly funded the first phase of a gas processing liquids optimization project that has the specific purposes to: Improve the return of processing natural gas liquids, Develop sets of control algorithms, Make available a low-cost solution suitable for small to medium-sized gas processing plants, Test and demonstrate the feasibility of line control. The ARCO Willard CO 2 gas recovery processing plant was chosen as the initial test site to demonstrate the application of multivariable on-line optimal control. One objective of this project is to support an R ampersand D effort to provide a standardized solution to the various types of gas processing plants in the U.S. Processes involved in these gas plants include cryogenic separations, demethanization, lean oil absorption, fractionation and gas treating. Next, the proposed solutions had to be simple yet comprehensive enough to allow an operator to maintain product specifications while operating over a wide range of gas input flow and composition. This had to be a supervisors system that remained on-line more than 95% of the time, and achieved reduced plant operating variability and improved variable cost control. It took more than a year to study various gas processes and to develop a control approach before a real application was finally exercised. An initial process for C 2 and CO 2 recoveries was chosen

Variability among inbred lines and RFLP mapping of sunflower isozymes

Directory of Open Access Journals (Sweden)

Carrera Alicia D.

2002-01-01

Full Text Available Eight isozyme systems were used in this study: acid phosphatase (ACP, alcohol dehydrogenase (ADH, esterase (EST, glutamate dehydrogenase (GDH, malate dehydrogenase (MDH, phosphoglucoisomerase (PGI, 6-phosphogluconate dehydrogenase (PGD, and phosphoglucomutase (PGM. The polymorphism of these enzyme systems was studied in 25 elite inbred lines. A total of 19 loci were identified, but only eight of them were polymorphic in the germplasm tested. The polymorphic index for the eight informative markers ranged from 0.08 to 0.57, with a mean value of 0.36. Five isozyme loci were mapped in F2:3 populations with existing RFLP data. Est-1, Gdh-2 and Pgi-2 were mapped to linkage groups 3, 14 and 9, respectively. As in previous reports, an ACP locus and a PGD locus were found to be linked, both located in linkage group 2 of the public sunflower map.

Transmission Line for 258 GHz Gyrotron DNP Spectrometry

Science.gov (United States)

Bogdashov, Alexandr A.; Belousov, Vladimir I.; Chirkov, Alexey V.; Denisov, Gregory G.; Korchagin, Vyacheslav V.; Kornishin, Sergey Yu.; Tai, Evgeny M.

2011-06-01

We describe the design and test results of the transmission line for liquid-state (LS) and solid-state (SS) DNP spectrometers with the second-harmonic 258.6 GHz gyrotron at the Institute of the Biophysical Chemistry Center of Goethe University (Frankfurt). The 13-meter line includes a mode converter, HE11 waveguides, 4 mitre bends, a variable polarizer-attenuator, directional couplers, a water-flow calorimeter and a mechanical switch. A microwave power of about 15 W was obtained in the pure HE11 mode at the spectrometer inputs.

THE NEW ECLIPSING CV MASTER OTJ192328.22+612413.5—A POSSIBLE SW SEXTANTIS STAR

International Nuclear Information System (INIS)

Kennedy, M. R.; Callanan, P.; Bouanane, S.; Garnavich, P. M.; Rose, B. M.; Szkody, P.; Bendjoya, P.; Abe, L.; Rivet, J. P.; Suarez, O.

2016-01-01

We present optical photometry and spectroscopy of the new eclipsing cataclysmic variable MASTER OTJ192328.22+612413.5, discovered by the MASTER team. We find the orbital period to be P = 0.16764612(5) day/4.023507(1) hr. The depth of the eclipse (2.9 ± 0.1 mag) suggests that the system is nearly edge on, and modeling of the system confirms the inclination to be between 81.°3 and 83.°6. The brightness outside the eclipse varies between observations, with a change of 1.6 ± 0.1 mag. Spectroscopy reveals double-peaked Balmer emission lines. By using spectral features matching a late M-type companion, we bound the distance to be 750 ± 250 pc, depending on the companion’s spectral type. The source displays 2 mag brightness changes on timescales of days. The amplitude of these changes, along with the spectrum at the faint state, suggest that the system is possibly a dwarf nova. The lack of any high-excitation He ii lines suggests that this system is not magnetically dominated. The light curve in both quiescence and outburst resembles that of Lanning 386, implying MASTER OTJ192328.22+612413.5 is a possible cross between a dwarf nova and a SW Sextantis star.

THE NEW ECLIPSING CV MASTER OTJ192328.22+612413.5—A POSSIBLE SW SEXTANTIS STAR

Energy Technology Data Exchange (ETDEWEB)

Kennedy, M. R.; Callanan, P.; Bouanane, S. [Department of Physics, University College Cork, Cork (Ireland); Garnavich, P. M.; Rose, B. M. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Szkody, P. [Department of Astronomy, University of Washington, Seattle, WA (United States); Bendjoya, P.; Abe, L.; Rivet, J. P.; Suarez, O., E-mail: markkennedy@umail.ucc.ie [Laboratoire Lagrange UMR 7293, Université de Nice Sophia-Antipolis, Observatoire de la Côte d’Azur (France)

2016-07-01

We present optical photometry and spectroscopy of the new eclipsing cataclysmic variable MASTER OTJ192328.22+612413.5, discovered by the MASTER team. We find the orbital period to be P = 0.16764612(5) day/4.023507(1) hr. The depth of the eclipse (2.9 ± 0.1 mag) suggests that the system is nearly edge on, and modeling of the system confirms the inclination to be between 81.°3 and 83.°6. The brightness outside the eclipse varies between observations, with a change of 1.6 ± 0.1 mag. Spectroscopy reveals double-peaked Balmer emission lines. By using spectral features matching a late M-type companion, we bound the distance to be 750 ± 250 pc, depending on the companion’s spectral type. The source displays 2 mag brightness changes on timescales of days. The amplitude of these changes, along with the spectrum at the faint state, suggest that the system is possibly a dwarf nova. The lack of any high-excitation He ii lines suggests that this system is not magnetically dominated. The light curve in both quiescence and outburst resembles that of Lanning 386, implying MASTER OTJ192328.22+612413.5 is a possible cross between a dwarf nova and a SW Sextantis star.

Winds in cataclysmic variable stars

International Nuclear Information System (INIS)

Cordova, F.A.; Ladd, E.F.; Mason, K.O.

1984-01-01

Ultraviolet spectrophotometry of two dwarf novae, CN Ori and RX And, at various phases of their outburst cycles confirms that the far uv flux increases dramatically about 1-2 days after the optical outburst begins. At this time the uv spectral line profiles indicate the presence of a high velocity wind. The detectability of the wind depends more on the steepness of the spectrum, and thus on the flux in the extreme ultraviolet, than on the absolute value of the far uv luminosity. The uv continuum during outburst consists of (at least) two components, the most luminous of which is located behind the wind and is completely absorbed by the wind at the line frequencies. Several pieces of evidence suggest that the uv emission lines that are observed in many cataclysmic variables during quiescence have a different location in the binary than the wind, and are affected very little by the outburst

A pulse-tube refrigerator using variable-resistance orifice

Science.gov (United States)

Huang, B. J.; Sun, B. W.

2003-01-01

In the present study, we propose a new design of orifice pulse-tube refrigerator (VROPT) using a variable-resistance valve to replace the conventional orifice. The variable-resistance orifice (VRO) is basically a high-speed solenoidal valve similar to the fuel jet device widely used in automobile engines. By changing the frequency and periods of ON and OFF of the valve through an electronic device, we can change the flow resistance of the VRO. This thus provides a possibility for an OPT to be controlled on-line during operation. From the results obtained in the present study, we have shown that VROPT is able to achieve on-line control by regulating the duty cycle d or frequency fv of the VRO. We also show that VROPT will not loss its thermal performance as compared to conventional OPT.

Spectroscopic investigation of wave driven microwave plasmas

International Nuclear Information System (INIS)

Wijtvliet, R.; Felizardo, E.; Tatarova, E.; Dias, F. M.; Ferreira, C. M.; Nijdam, S.; Veldhuizen, E. V.; Kroesen, G.

2009-01-01

Large H atom line broadening was found throughout the volume of surface wave generated He-H 2 and H 2 microwave plasmas at low pressures. The measured Doppler temperatures corresponding to the H β , H γ , H δ , H ε , and H ζ line profiles were found to be higher than the rotational temperature of the hydrogen molecular Fulcher-α band and the Doppler temperature of the 667.1 nm singlet He line. No excessive broadening has been found. The Lorentzian and Gaussian widths as determined by fitting the spectral lines with a Voigt profile increase with the principal quantum number of the upper level. In contrast, no such dependence for the Gaussian width has been observed in an Ar-H 2 discharge. No population inversion has been observed from measurements of the relative intensities of transitions within the Balmer series.

DISCOVERY OF A WOLF-RAYET STAR THROUGH DETECTION OF ITS PHOTOMETRIC VARIABILITY

Energy Technology Data Exchange (ETDEWEB)

Littlefield, Colin [Law School, University of Notre Dame, Notre Dame, IN 46556 (United States); Garnavich, Peter; McClelland, Colin; Rettig, Terrence [Physics Department, University of Notre Dame, Notre Dame, IN 46556 (United States); Marion, G. H. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Vinko, Jozsef [Department of Optics, University of Szeged (Hungary); Wheeler, J. Craig [Astronomy Department, University of Texas, Austin, TX 78712 (United States)

2012-06-15

We report the serendipitous discovery of a heavily reddened Wolf-Rayet star that we name WR 142b. While photometrically monitoring a cataclysmic variable, we detected weak variability in a nearby field star. Low-resolution spectroscopy revealed a strong emission line at 7100 A, suggesting an unusual object and prompting further study. A spectrum taken with the Hobby-Eberly Telescope confirms strong He II emission and an N IV 7112 A line consistent with a nitrogen-rich Wolf-Rayet star of spectral class WN6. Analysis of the He II line strengths reveals no detectable hydrogen in WR 142b. A blue-sensitive spectrum obtained with the Large Binocular Telescope shows no evidence for a hot companion star. The continuum shape and emission line ratios imply a reddening of E(B - V) = 2.2-2.6 mag. We estimate that the distance to WR 142b is 1.4 {+-} 0.3 kpc.

DISCOVERY OF A WOLF-RAYET STAR THROUGH DETECTION OF ITS PHOTOMETRIC VARIABILITY

International Nuclear Information System (INIS)

Littlefield, Colin; Garnavich, Peter; McClelland, Colin; Rettig, Terrence; Marion, G. H.; Vinkó, József; Wheeler, J. Craig

2012-01-01

We report the serendipitous discovery of a heavily reddened Wolf-Rayet star that we name WR 142b. While photometrically monitoring a cataclysmic variable, we detected weak variability in a nearby field star. Low-resolution spectroscopy revealed a strong emission line at 7100 Å, suggesting an unusual object and prompting further study. A spectrum taken with the Hobby-Eberly Telescope confirms strong He II emission and an N IV 7112 Å line consistent with a nitrogen-rich Wolf-Rayet star of spectral class WN6. Analysis of the He II line strengths reveals no detectable hydrogen in WR 142b. A blue-sensitive spectrum obtained with the Large Binocular Telescope shows no evidence for a hot companion star. The continuum shape and emission line ratios imply a reddening of E(B – V) = 2.2-2.6 mag. We estimate that the distance to WR 142b is 1.4 ± 0.3 kpc.

Formation and Characterization of Inkjet-Printed Nanosilver Lines on Plasma-Treated Glass Substrates

Directory of Open Access Journals (Sweden)

Jae-Sung Kwon

2018-02-01

Full Text Available In this study, we investigated geometrical characteristics of the inkjet-printed lines with non-zero receding contact angle (CA on plasma-treated substrates in terms of various printing variables and analyzed the fluidic behavior and hydrodynamic instability involved in the line formation process. The printing variables included surface energy, droplet overlap ratio, printing frequency, a number of ink droplets, substrate temperature and printing procedures. For the study, a colloidal suspension containing 56 wt % silver nanoparticles in tetradecane solvent was used as a printing ink. It has electrical resistivity of 4.7 μΩ·cm. The substrates were obtained by performing a plasma enhanced chemical vapor deposition (PECVD process with C4F8 and O2 under various treatment conditions. As results of the experiments, the surface shape and pattern of the inkjet-printed Ag lines were dominantly influenced by the surface energy of the substrates, among the printing variables. Accordingly even when the receding CA was non-zero, bulging instability of the lines occurred forming separate circular patterns or regular bulges connected by ridges. It is a new finding of this study, which is completely different with the bulging instability of inkjet lines with zero receding CA specified by previous researches. The bulging instability decreased by increasing surface temperature of the substrates or employing interlacing procedure instead of continuous procedure for printing. The interlacing procedure also was advantageous to fabricate thick and narrow Ag lines with well-defined shape through overprinting on a hydrophobic substrate. These results will contribute greatly to not only the production of various printed electronics containing high-aspect-ratio structures but also the improvement of working performance of the devices.

A Hierarchical Bayesian Model to Predict Self-Thinning Line for Chinese Fir in Southern China.

Directory of Open Access Journals (Sweden)

Xiongqing Zhang

Full Text Available Self-thinning is a dynamic equilibrium between forest growth and mortality at full site occupancy. Parameters of the self-thinning lines are often confounded by differences across various stand and site conditions. For overcoming the problem of hierarchical and repeated measures, we used hierarchical Bayesian method to estimate the self-thinning line. The results showed that the self-thinning line for Chinese fir (Cunninghamia lanceolata (Lamb.Hook. plantations was not sensitive to the initial planting density. The uncertainty of model predictions was mostly due to within-subject variability. The simulation precision of hierarchical Bayesian method was better than that of stochastic frontier function (SFF. Hierarchical Bayesian method provided a reasonable explanation of the impact of other variables (site quality, soil type, aspect, etc. on self-thinning line, which gave us the posterior distribution of parameters of self-thinning line. The research of self-thinning relationship could be benefit from the use of hierarchical Bayesian method.

Skills Associated with Line Breaks in Elite Rugby Union

Directory of Open Access Journals (Sweden)

Steve den Hollander, James Brown, Michael Lambert, Paul Treu, Sharief Hendricks

2016-09-01

Full Text Available The ability of the attacking team to break through the defensive line is a key indicator of success as it creates opportunities to score tries. The aim of this study was to analyse line breaks and identify the associated skills and playing characteristics. The 2013 Super Rugby season (125 games was analysed, in which 362 line breaks were identified and coded using variables that assessed team patterns and non-contact attacking skills in the phases preceding the line break. There was an average of 3 line breaks per game, with 39% of line breaks resulting in a try. Line breaks occurred when the ball-carrier was running fast [61%, x2(4 = 25.784, p = 0.000, Cramer’s v = 0.1922, weak]. At a moderate distance, short lateral passes (19% and skip passes (15% attributed to the highest percentage of line breaks [x2(26 = 50.899, p = 0.036, Cramer’s v = 0.2484, moderate]. Faster defensive line speeds resulted in more line breaks [x2(12 = 61.703, p < 0.001, Cramer’s v = 0.3026, moderate]. Line breaks are associated with overall team success and try scoring opportunities. Awareness of the defenders line speed and depth, fast running speed when receiving the ball and quick passing between attackers to the outside backs creates line break opportunities. During training, coaches should emphasise the movement speed of the ball between attackers and manipulate the speed and distance of the defenders.

HIGH-REDSHIFT SDSS QUASARS WITH WEAK EMISSION LINES

International Nuclear Information System (INIS)

Diamond-Stanic, Aleksandar M.; Fan Xiaohui; Jiang Linhua; Kim, J. Serena; Schmidt, Gary D.; Smith, Paul S.; Vestergaard, Marianne; Young, Jason E.; Brandt, W. N.; Shemmer, Ohad; Gibson, Robert R.; Schneider, Donald P.; Strauss, Michael A.; Shen Yue; Anderson, Scott F.; Carilli, Christopher L.; Richards, Gordon T.

2009-01-01

We identify a sample of 74 high-redshift quasars (z > 3) with weak emission lines from the Fifth Data Release of the Sloan Digital Sky Survey and present infrared, optical, and radio observations of a subsample of four objects at z > 4. These weak emission-line quasars (WLQs) constitute a prominent tail of the Lyα + N v equivalent width distribution, and we compare them to quasars with more typical emission-line properties and to low-redshift active galactic nuclei with weak/absent emission lines, namely BL Lac objects. We find that WLQs exhibit hot (T ∼ 1000 K) thermal dust emission and have rest-frame 0.1-5 μm spectral energy distributions that are quite similar to those of normal quasars. The variability, polarization, and radio properties of WLQs are also different from those of BL Lacs, making continuum boosting by a relativistic jet an unlikely physical interpretation. The most probable scenario for WLQs involves broad-line region properties that are physically distinct from those of normal quasars.

Multi-step lining-up correction of the CLIC trajectory

CERN Document Server

D'Amico, T E

1999-01-01

In the CLIC main linac it is very important to minimise the trajectory excursion and consequently the emittance dilution in order to obtain the required luminosity. Several algorithms have been proposed and lately the ballistic method has proved to be very effective. The trajectory correction method described hereafter retains the main advantages of the latter while adding some interesting features. It is based on the separation of the unknown variables like the quadrupole misalignments, the offset and slope of the injection straight line and the misalignments of the beam position monitors (BPM). This is achieved by referring the trajectory relatively to the injection line and not to the average pre-alignment line and by using two trajectories each corresponding to slightly different quadrupole strengths. A reference straight line is then derived onto which the beam is bent by a kick obtained by moving the first quadrupole. The other quadrupoles are then aligned on that line. The quality of the correction dep...

Systematic Derivation of Static Analyses for Software Product Lines

DEFF Research Database (Denmark)

Midtgaard, Jan; Brabrand, Claus; Wasowski, Andrzej

2014-01-01

A recent line of work lifts particular verification and analysis methods to Software Product Lines (SPL). In an effort to generalize such case-by-case approaches, we develop a systematic methodology for lifting program analyses to SPLs using abstract interpretation. Abstract interpretation...... for lifting analyses and Galois connections. We prove that for analyses developed using our method, the soundness of lifting follows by construction. Finally, we discuss approximating variability in an analysis and we derive variational data-flow equations for an example analysis, a constant propagation...

Spectropolarimetry, variability, and the taxonomy of active galactic nuclei

International Nuclear Information System (INIS)

Goodrich, R.W.

1988-01-01

Two subclasses of active galactic nuclei (AGN) are studied using spectropolarimetry, with the intent of defining the relationships of the subclasses to other classes of AGNs, and to study the physics of the objects themselves. In the Seyfert 1.8/1.9 class there is good evidence for dust just outside of the broad-line regions in two objects, IRAS 1958-183 and NGC 2622. Spectropolarimetry of the latter object reveals the presence of dust moving at ∼ -800 s -1 along the our line-of-sight, and causing much of the polarization in the object. In addition, three of these objects have undergone extreme variability. Combining IDS data from Osterbrock and collaborators with the more recent CCD data it is shown that in all three cases the changes in both broad emission line fluxes and featureless continuum are consistent with changes in the line-of-sight reddening to the broad-line region. Together with the polarimetric evidence for dust and IRAS photometry this strongly suggests that the Seyfert 1.8/1.9 character is caused by dust and the consequent reddening and extinction. Variability occurs when dust clouds evaporate or move out of line-of-sight, and the extinction then changes. In the so-called narrow line Seyfert 1s spectropolarimetry reveals seven highly-polarized objects. In Mrk 1239 there is evidence for at least two components of polarization, one probably due to dust reflection. In two other objects, Mrk 766 and IRAS 1509-211, the polarization also appears to indicate dust reflection as the polarigenic mechanism. There is a weak circumstantial evidence for an association of the low-density region and the polarizing source, provided by comparison of the radio axes and polarization position angles in Mrk 766 and Mrk 1126

An emission-line model for AM Herculis systems

International Nuclear Information System (INIS)

Ferrario, L.; Tuohy, I.R.; Wickramasinghe, D.T.; Australian National Univ., Canberra)

1989-01-01

The optical spectra of the AM Herculis binaries are characterized by extremely complex emission lines whose profiles can be resolved into at least three components which are formed in different regions of the accretion stream leading from the companion star toward the magnetic white dwarf. A theoretical model is presented for the radial velocity and velocity dispersion of the broad emission line component assuming that it originates mainly in the gas which is diverted out of the orbital plane and funneled onto the white dwarf surface along magnetic field lines. The model is used to locate the line-forming region in three AM Her variables: E1405-451, CW 1103+254, and EXO 033319-2554.2, using as constraints the radial velocity and velocity dispersion data. The analyses of these systems show that the material is threaded by the magnetic field in a very azimuthally extended coupling region located 0.5-0.75 of the way between the white dwarf and the inner Lagrange point. 36 refs

Optical and Near-infrared Study of Nova V2676 Oph 2012

Energy Technology Data Exchange (ETDEWEB)

Raj, A. [Korea Astronomy and Space Science Institute, Daejeon, 34055 (Korea, Republic of); Das, R. K. [Department of Astrophysics and Cosmology, S N Bose National Centre for Basic Sciences, Salt Lake, Kolkata 700106 (India); Walter, F. M., E-mail: ashish.raj@iiap.res.in [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)

2017-02-01

We present optical spectrophotometric and near-infrared (NIR) photometric observations of the nova V2676 Oph covering the period from 2012 March 29 through 2015 May 8. The optical spectra and photometry of the nova have been taken from SMARTS and Asiago; the NIR photometry was obtained from SMARTS and Mt. Abu. The spectra were dominated by strong H i lines from the Balmer series, Fe ii, N i, and [O i] lines in the initial days, typical of an Fe ii type nova. The measured FWHM for the H β and H α lines was 800–1200 km s{sup −1}. There was pronounced dust formation starting 90 days after the outburst. The J − K color was the largest among recent dust-forming novae.

Lip line preference for variant face types.

Science.gov (United States)

Anwar, Nabila; Fida, Mubassar

2012-06-01

To determine the effect of altered lip line on attractiveness and to find preferred lip line for vertical face types in both genders. Cross-sectional analytical study. The Aga Khan University Hospital, Karachi, from May to July 2009. Photographs of two selected subjects were altered to produce three face types for the same individual with the aim of keeping the frame of the smile constant. Lip line was then altered for both the subjects as: both dentitions visible, upper incisors visible, upper incisors and 2 mm gum and 4 mm gum visible. The pictures were rated by different professionals for attractiveness. Descriptive statistics for the raters and multiple factor ANOVA was used to find the most attractive lip line. The total number of raters was 100 with the mean age of 30.3 ± 8 years. The alterations in the smile parameters produced statistically significant difference in the attractiveness of faces, whereas the perception difference was found to be insignificant amongst raters of different professions. Preferred lip line was the one showing only the upper incisors in dolico and mesofacial male and female genders whereas 2 mm gum show was preferred in brachyfacial subjects. The variability in lip line showed significant difference in the perceived attractiveness. Preferred lip lines as the one showing only the upper incisors in dolico and mesofacial male and female genders whereas 2 mm gum show was preferred in brachyfacial subjects.

Adaptive settings of distance relay for MOV-protected series compensated line with distributed capacitance considering wind power

Science.gov (United States)

Sivov, Oleg Viktorovich

Series compensated lines are protected from overvoltage by metal-oxide-varistors (MOVs) connected in parallel with the capacitor bank. The nonlinear characteristics of MOV devices add complexity to fault analysis and distance protection operation. During faults, the impedance of the line is modified by an equivalent impedance of the parallel MOV/capacitor circuit, which affects the distance protection. The intermittent wind generation introduces additional complexity to the system performance and distance protection. Wind variation affects the fault current level and equivalent MOV/capacitor impedance during a fault, and hence the distance relay operation. This thesis studies the impact of the intermittent wind power generation on the operation of MOV during faults. For the purpose of simulation, an equivalent wind farm model is proposed to generate a wind generation profile using wind farm generation from California independent system operator (ISO) as a guide for wind power variation to perform the study. The IEEE 12-bus test system is modified to include MOV-protected series capacitor and the equivalent wind farm model. The modified test system is simulated in the MATLAB/Simulink environment. The study has been achieved considering three phase and single line to ground (SLG) faults on the series compensated line to show the effect of wind variation on the MOV operation. This thesis proposes an adaptive setting method for the mho relay distance protection of series compensated line considering effects of wind power variation and MOV operation. The distributed parameters of a transmission line are taken into account to avoid overreaching and underreaching of distance relays. The study shows that variable wind power affects system power flow and fault current in the compensated line during a fault which affects the operation of MOVs for different fault conditions. The equivalent per-phase impedance of the MOV/capacitor circuit has an effect on the system operation

Dissociative Excitation of Acetylene Induced by Electron Impact: Excitation-emission Cross-sections

Energy Technology Data Exchange (ETDEWEB)

Országh, Juraj; Danko, Marián; Čechvala, Peter; Matejčík, Štefan, E-mail: matejcik@fmph.uniba.sk [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Mlynská dolina F-2, 842 48 Bratislava (Slovakia)

2017-05-20

The optical emission spectrum of acetylene excited by monoenergetic electrons was studied in the range of 190–660 nm. The dissociative excitation and dissociative ionization associated with excitation of the ions initiated by electron impact were dominant processes contributing to the spectrum. The spectrum was dominated by the atomic lines (hydrogen Balmer series, carbon) and molecular bands (CH(A–X), CH(B–X), CH{sup +}(B–A), and C{sub 2}). Besides the discrete transitions, we have detected the continuum emission radiation of ethynyl radical C{sub 2}H(A–X). For most important lines and bands of the spectrum we have measured absolute excitation-emission cross sections and determined the energy thresholds of the particular dissociative channels.

The metallicity evolution of blue compact dwarf galaxies from the intermediate redshift to the local Universe

OpenAIRE

Lian, Jianhui; Hu, Ning; Fang, Guanwen; Ye, Chengyun; Kong, Xu

2016-01-01

We present oxygen abundance measurements for 74 blue compact dwarf (BCD) galaxies in the redshift range in [0.2, 0.5] using the strong-line method. The spectra of these objects are taken using Hectospec on the Multiple Mirror Telescope (MMT). More than half of these BCDs had dust attenuation corrected using the Balmer decrement method. For comparison, we also selected a sample of 2023 local BCDs from the Sloan Digital Sky Survey (SDSS) database. Based on the local and intermediate-z BCD sampl...

He 2-467 = LT Del - the yellow symbiotic star with a period about 500 days

International Nuclear Information System (INIS)

Arkhipova, V.P.; Noskova, R.I.

1988-01-01

By means of broad and narrow-band photometry in UBV spectral region the variability of the object He 2-467 earlier classified as peculiar cenral star of planetary nebyla has been revealed. The brightness amplitude significantly decreases with the wavelength from 1 m .9 in u-band to 0 m .3 in V. The brightness variations were found to be periodic, with P=488 days. The observations of He2-467 were interpreted using the model of binary consisting of very hot subdwarf and G511-giant. The parameters of both components have been derived. The hot star is probably the evolved low mass nucleus of planetary nebula already dissipated. The periodic variations in U-band may be the result of the reflection effect due to the presence of hot extended region on the side of cold star facing the subdwarf. The subdwarf UV-flux can heat and ionize the upper atmosphere of the giant giving birth to the emission lines and Balmer continuum. The yellow symbiotics to which He 2-467 belong may be predecessors of red symbiotics with M giants

SOLAR CYCLE VARIABILITY AND SURFACE DIFFERENTIAL ROTATION FROM Ca II K-LINE TIME SERIES DATA

Energy Technology Data Exchange (ETDEWEB)

Scargle, Jeffrey D.; Worden, Simon P. [NASA Ames Research Center, Moffett Field, CA, 94035 (United States); Keil, Stephen L. [National Solar Observatory, P.O. Box 57, Sunspot, NM 88349 (United States)

2013-07-01

Analysis of over 36 yr of time series data from the NSO/AFRL/Sac Peak K-line monitoring program elucidates 5 components of the variation of the 7 measured chromospheric parameters: (a) the solar cycle (period {approx} 11 yr), (b) quasi-periodic variations (periods {approx} 100 days), (c) a broadband stochastic process (wide range of periods), (d) rotational modulation, and (e) random observational errors, independent of (a)-(d). Correlation and power spectrum analyses elucidate periodic and aperiodic variation of these parameters. Time-frequency analysis illuminates periodic and quasi-periodic signals, details of frequency modulation due to differential rotation, and in particular elucidates the rather complex harmonic structure (a) and (b) at timescales in the range {approx}0.1-10 yr. These results using only full-disk data suggest that similar analyses will be useful for detecting and characterizing differential rotation in stars from stellar light curves such as those being produced by NASA's Kepler observatory. Component (c) consists of variations over a range of timescales, in the manner of a 1/f random process with a power-law slope index that varies in a systematic way. A time-dependent Wilson-Bappu effect appears to be present in the solar cycle variations (a), but not in the more rapid variations of the stochastic process (c). Component (d) characterizes differential rotation of the active regions. Component (e) is of course not characteristic of solar variability, but the fact that the observational errors are quite small greatly facilitates the analysis of the other components. The data analyzed in this paper can be found at the National Solar Observatory Web site http://nsosp.nso.edu/cak{sub m}on/, or by file transfer protocol at ftp://ftp.nso.edu/idl/cak.parameters.

Origins and implications of pluripotent stem cell variability and heterogeneity

Science.gov (United States)

Cahan, Patrick; Daley, George Q.

2014-01-01

Pluripotent stem cells constitute a platform to model disease and developmental processes and can potentially be used in regenerative medicine. However, not all pluripotent cell lines are equal in their capacity to differentiate into desired cell types in vitro. Genetic and epigenetic variations contribute to functional variability between cell lines and heterogeneity within clones. These genetic and epigenetic variations could ‘lock’ the pluripotency network resulting in residual pluripotent cells or alter the signalling response of developmental pathways leading to lineage bias. The molecular contributors to functional variability and heterogeneity in both embryonic stem (ES) cells and induced pluripotent stem (iPS) cells are only beginning to emerge, yet they are crucial to the future of the stem cell field. PMID:23673969

Gamma radiation induced and natural variability for nodulation in legumes

Energy Technology Data Exchange (ETDEWEB)

Maherchandani, N; Rana, O P.S. [Haryana Agricultural Univ., Hissar (India). Dept. of Genetics

1977-09-01

Gamma radiation induced variability for nodulation was studied in 112 M4 mutant lines of cowpea variety C-15-2. Ten lines superior in nodulation to the original variety have been identified. Natural variability for nodulation and plant growth was investigated in 75 genotypes of chickpea. A number of genotype were found to be superior to cultivated variety C-235 for nodulation characters. Nodule characters were found to be related to dry matter accumulation but not to grain yield. Another experiment on 10 varieties of chick pea conducted under aseptic conditions revealed that host genotypes showed specificity for Rhizobial strains and different Rhizobial strains differed in their effectiveness on different host genotypes. H 551 and H 355 were the most responsive varieties.

Origins and implications of pluripotent stem cell variability and heterogeneity

OpenAIRE

Cahan, Patrick; Daley, George Q.

2013-01-01

Pluripotent stem cells constitute a platform to model disease and developmental processes and can potentially be used in regenerative medicine. However, not all pluripotent cell lines are equal in their capacity to differentiate into desired cell types in vitro. Genetic and epigenetic variations contribute to functional variability between cell lines and heterogeneity within clones. These genetic and epigenetic variations could ‘lock’ the pluripotency network resulting in residual pluripotent...

Variable quasi-stellar sources with particular emphasis on objects of the BL Lac type

International Nuclear Information System (INIS)

Kinman, T.D.

1975-01-01

The optically variable quasars tend to have steep optical spectra and to show variable polarization; they tend to be associated with compact radio sources which have flat radio spectra at GHz frequencies. Objects are known which have continuous spectra (like BL Lac and OJ 287), but whose other properties closely parallel those of the variable quasars and N galaxies; in fact no sharp distinction can be drawn between them. The variation in the visibility of emission lines in quasars and N galaxies could be due to variations in the strength and spectral index of the radiation from the non-thermal source and from the differences in the amount and disposition of the material around it; it does not seem likely that a combination of these factors accounts for the observed range in emission line strength. The systematic difference in optical spectral index between continuous-spectrum objects (and OVV variables) on the one hand and those with emission lines on the other will produce a difference in K term between them, which may be expected to affect their distributions with respect to apparent magnitude. (Auth.)

BROAD BALMER WINGS IN BA HYPER/SUPERGIANTS DISTORTED BY DIFFUSE INTERSTELLAR BANDS: FIVE EXAMPLES IN THE 30 DORADUS REGION FROM THE VLT-FLAMES TARANTULA SURVEY

Energy Technology Data Exchange (ETDEWEB)

Walborn, Nolan R.; Sana, Hugues; Sabbi, Elena, E-mail: walborn@stsci.edu, E-mail: hsana@stsci.edu, E-mail: sabbi@stsci.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); and others

2015-08-10

Extremely broad emission wings at Hβ and Hα have been found in VLT-FLAMES Tarantula Survey data for five very luminous BA supergiants in or near 30 Doradus in the Large Magellanic Cloud. The profiles of both lines are extremely asymmetrical, which we have found to be caused by very broad diffuse interstellar bands (DIBs) in the longward wing of Hβ and the shortward wing of Hα. These DIBs are well known to interstellar but not to many stellar specialists, so that the asymmetries may be mistaken for intrinsic features. The broad emission wings are generally ascribed to electron scattering, although we note difficulties for that interpretation in some objects. Such profiles are known in some Galactic hyper/supergiants and are also seen in both active and quiescent Luminous Blue Variables (LBVs). No prior or current LBV activity is known in these 30 Dor stars, although a generic relationship to LBVs is not excluded; subject to further observational and theoretical investigation, it is possible that these very luminous supergiants are approaching the LBV stage for the first time. Their locations in the HRD and presumed evolutionary tracks are consistent with that possibility. The available evidence for spectroscopic variations of these objects is reviewed, while recent photometric monitoring does not reveal variability. A search for circumstellar nebulae has been conducted, with an indeterminate result for one of them.

FLARE-LIKE VARIABILITY OF THE Mg II {lambda}2800 EMISSION LINE IN THE {gamma}-RAY BLAZAR 3C 454.3

Energy Technology Data Exchange (ETDEWEB)

Leon-Tavares, J. [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Vaeisaelaentie 20, FI-21500 Piikkioe (Finland); Chavushyan, V.; Patino-Alvarez, V.; Carraminana, A.; Carrasco, L. [Instituto Nacional de Astrofisica Optica y Electronica (INAOE), Apartado Postal 51 y 216, 72000 Puebla (Mexico); Valtaoja, E. [Tuorla Observatory, Department of Physics and Astronomy, University of Turku, FI-20100 Turku (Finland); Arshakian, T. G. [I. Physikalisches Institut, Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Popovic, L. C. [Astronomical Observatory, Volgina 7, 11160 Belgrade 74 (Serbia); Tornikoski, M.; Laehteenmaeki, A. [Aalto University Metsaehovi Radio Observatory, Metsaehovintie 114, FI-02540 Kylmaelae (Finland); Lobanov, A. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany)

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, then 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.

Gamma ray induced diversity in restorer line of cotton (Gossypium Hirsutum)

International Nuclear Information System (INIS)

Mehetre, S.S.; Patil, V.R.; Surana, P.P.

2000-01-01

Looking to the limitation of very few restorers available in cotton a diversification of available restorer line was undertaken by gamma irradiation. The four hundred individual plants selected from individual M 2 families were crossed with CMS lines. Out of which 12 plants restored fertility in CMS lines and their F 1 's with CMS produced more heterotic hybrids than their checks (control). The results indicated that sufficient variability can be induced with the help of gamma rays and the diversification of restorers is possible within a short period with simultaneous improvement in either one or two characters. (author)

Radial velocity asymmetries from jets with variable velocity profiles

International Nuclear Information System (INIS)

Cerqueira, A. H.; Vasconcelos, M. J.; Velazquez, P. F.; Raga, A. C.; De Colle, F.

2006-01-01

We have computed a set of 3-D numerical simulations of radiatively cooling jets including variabilities in both the ejection direction (precession) and the jet velocity (intermittence), using the Yguazu-a code. In order to investigate the effects of jet rotation on the shape of the line profiles, we also introduce an initial toroidal rotation velocity profile. Since the Yguazu-a code includes an atomic/ionic network, we are able to compute the emission coefficients for several emission lines, and we generate line profiles for the Hα, [O I]λ6300, [S II]λ6716 and [N II]λ6548 lines. Using initial parameters that are suitable for the DG Tau microjet, we show that the computed radial velocity shift for the medium-velocity component of the line profile as a function of distance from the jet axis is strikingly similar for rotating and non-rotating jet models

Selection of common bean lines with high grain yield and high grain calcium and iron concentrations

Directory of Open Access Journals (Sweden)

Nerinéia Dalfollo Ribeiro

2014-02-01

Full Text Available Genetic improvement of common bean nutritional quality has advantages in marketing and can contribute to society as a food source. The objective of this study was to evaluate the genetic variability for grain yield, calcium and iron concentrations in grains of inbred common bean lines obtained by different breeding methods. For this, 136 F7 inbred lines were obtained using the Pedigree method and 136 F7 inbred lines were obtained using the Single-Seed Descent (SSD method. The lines showed genetic variability for grain yield, and concentrations of calcium and iron independently of the method of advancing segregating populations. The Pedigree method allows obtaining a greater number of lines with high grain yield. Selection using the SSD method allows the identification of a larger number of lines with high concentrations of calcium and iron in grains. Weak negative correlations were found between grain yield and calcium concentration (r = -0.0994 and grain yield and iron concentration (r = -0.3926. Several lines show genetic superiority for grain yield and concentrations of calcium and iron in grains and their selection can result in new common bean cultivars with high nutritional quality.

Flexible Software Process Lines in Practice

DEFF Research Database (Denmark)

Kuhrmann, Marco; Ternité, Thomas; Friedrich, Jan

2016-01-01

Process flexibility and adaptability is a frequently discussed topic in literature, and several approaches propose techniques to improve and optimize software processes for a given organization- or project context. A software process line (SPrL) is an instrument to systematically construct...... that can be adapted to the respective context. In this article, we present an approach to construct flexible software process lines and show its practical application in the German V-Modell XT. The presented approach emerges from a 10-year research endeavor and was used to enhance the metamodel of the V......-Modell XT and to allow for improved process variability and lifecycle management. Practical dissemination and complementing empirical research show the suitability of the concept. We therefore contribute a proven approach that is presented as metamodel fragment for reuse and implementation in further...

ACTIVE POWER LOSSES IN LONG LINES DURING COORDINATED, LIMITING AND MALFUNCTION BEHAVIOR

Directory of Open Access Journals (Sweden)

Rimsky V.X.

2008-04-01

Full Text Available Exact formulas for calculation of limiting values of transmitted capacity and efficiency of lines of a variable voltage with active loading on the reception end are resulted. Critical resistance and losses of capacity are determined depending on length Air-lines of an electricity transmission of a class of a voltage 500 … 750 kV. Emergency operation in the loaded electricity transmission is investigated.

Form of relativistic dynamics with world lines

International Nuclear Information System (INIS)

Mukunda, N.; Sudarshan, E.C.G.

1981-01-01

In any Hamiltonian relativistic theory there are ten generators of the Poincare group which are realized canonically. The dynamical evolution is described by a Hamiltonian which is one of the ten generators in Dirac's generator formalism. The requirement that the canonical transformations reproduce the geometrical transformation of world points generates the world-line conditions. The Dirac identification of the Hamiltonian and the world-line conditions together lead to the no-interaction theorem. Interacting relativistic theories with world-line conditions should go beyond the Dirac theory and have eleven generators. In this paper we present a constraint dynamics formalism which describes an eleven-generator theory of N interacting particles using 8(N+1) variables with suitable constraints. The (N+1)th pair of four-vectors is associated with the uniform motion of a center which coincides with the center of energy for free particles. In such theories dynamics and kinematics cannot be separated out in a simple fashion

KINEMATIC ANALYSIS OF LINE-OUT THROWING IN ELITE INTERNATIONAL RUGBY UNION

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Mark G.L. Sayers

2011-09-01

Full Text Available The rugby union line-out is a key aspect of game play and involves players from both teams contesting for the ball after it has been thrown in from the side line. Successful lines-out throws require the ball to be delivered accurately to the hands of a jumping and/or lifted team mate (approximately 3-3.5 m off the ground over distances of between 5- 18 m. Previous research has suggested considerable inter and intra-individual differences in the throwing techniques of international level players. Accordingly, this project investigated the interrelationships between accuracy and the line-out throwing characteristics of three elite international rugby players, and then analyzed whether these changed for throws over increasing length. Three-dimensional (3D data were developed from video footage (50 Hz of three elite international subjects for 30 throws over three distances (6 m, 10 m, and 15 m. Results showed notable differences between subjects in many variables at each of the key throw phases. However, several variables such as the degree of trunk flexion at the end of the backswing and at ball release, coupled with elbow flexion angle at ball release remained constant as throw length increased. All subjects exhibited high levels of consistency in movement patterns across all throw lengths. Findings indicated that these high performance line-out throwers shared several common characteristics that will provide useful guides in the development of training programs

ABL tyrosine kinase inhibition variable effects on the invasive properties of different triple negative breast cancer cell lines.

Directory of Open Access Journals (Sweden)

Clément Chevalier

Full Text Available The non-receptor tyrosine kinase ABL drives myeloid progenitor expansion in human chronic myeloid leukemia. ABL inhibition by the tyrosine kinase inhibitor nilotinib is a first-line treatment for this disease. Recently, ABL has also been implicated in the transforming properties of solid tumors, including triple negative (TN breast cancer. TN breast cancers are highly metastatic and several cell lines derived from these tumors display high invasive activity in vitro. This feature is associated with the activation of actin-rich membrane structures called invadopodia that promote extracellular matrix degradation. Here, we investigated nilotinib effect on the invasive and migratory properties of different TN breast cancer cell lines. Nilotinib decreased both matrix degradation and invasion in the TN breast cancer cell lines MDA-MB 231 and MDA-MB 468. However, and unexpectedly, nilotinib increased by two-fold the invasive properties of the TN breast cancer cell line BT-549 and of Src-transformed fibroblasts. Both display much higher levels of ABL kinase activity compared to MDA-MB 231. Similar effects were obtained by siRNA-mediated down-regulation of ABL expression, confirming ABL central role in this process. ABL anti-tumor effect in BT-549 cells and Src-transformed fibroblasts was not dependent on EGF secretion, as recently reported in neck and squamous carcinoma cells. Rather, we identified the TRIO-RAC1 axis as an important downstream element of ABL activity in these cancer cells. In conclusion, the observation that TN breast cancer cell lines respond differently to ABL inhibitors could have implications for future therapies.

Régression orthogonale de trois variables liées Orthogonal Regression of Linked Variables

Directory of Open Access Journals (Sweden)

Phelizon J. -F.

2006-11-01

Full Text Available On propose dans cet article un algorithme permettant de déterminer les paramètres de l'équation de régression orthogonale de trois variables liées par une relation linéaire. Cet algorithme est remarquablement simple puisqu'il n'implique pas de devoir calculer les valeurs propres de la matrice des covariances. D'autre part, on montre que l'équation obtenue (celle d'une droite dans l'espace à trois dimensions caractérise aussi une droite dans un diagramme triangulaire, ce qui rend l'interprétation des résultats immédiate. L'exposé théorique se poursuit par deux exemples qui ont été effectivement testés sur ordinateur. This article proposes on algorithm for determining the parameters of the equation for the orthogonal regression of three variables linked by a linear relation. This algorithm is remarkably simple in that il does not require the actual values of the covariance matrix to be calculated. In addition, the equation obtained (for a straight line in three-dimensional space is shown to characterize a straight line in a triang ular diagram as well, thus making il immediately possible ta interpret the resulis. The theoretical explanation continues with two examples that were actually tried out on a computer.

VARIABILITY IN OPTICAL SPECTRA OF ε ORIONIS

International Nuclear Information System (INIS)

Thompson, Gregory B.; Morrison, Nancy D.

2013-01-01

We present the results of a time series analysis of 130 échelle spectra of ε Ori (B0 Ia), acquired over seven observing seasons between 1998 and 2006 at Ritter Observatory. The equivalent widths of Hα (net) and He I λ5876 were measured and radial velocities were obtained from the central absorption of He I λ5876. Temporal variance spectra (TVS) revealed significant wind variability in both Hα and He I λ5876. The He I TVS have a double-peaked profile consistent with radial velocity oscillations. A periodicity search was carried out on the equivalent width and radial velocity data, as well as on wavelength-binned spectra. This analysis has revealed several periods in the variability with timescales of two to seven days. Many of these periods exhibit sinusoidal modulation in the associated phase diagrams. Several of these periods were present in both Hα and He I, indicating a possible connection between the wind and the photosphere. Due to the harmonic nature of these periods, stellar pulsations may be the origin of some of the observed variability. Periods on the order of the rotational period were also detected in the He I line in the 1998-1999 season and in both lines during the 2004-2005 season. These periods may indicate rotational modulation due to structure in the wind.

Radiation-induced alterations of histone post-translational modification levels in lymphoblastoid cell lines

International Nuclear Information System (INIS)

Maroschik, Belinda; Gürtler, Anne; Krämer, Anne; Rößler, Ute; Gomolka, Maria; Hornhardt, Sabine; Mörtl, Simone; Friedl, Anna A

2014-01-01

Radiation-induced alterations in posttranslational histone modifications (PTMs) may affect the cellular response to radiation damage in the DNA. If not reverted appropriately, altered PTM patterns may cause long-term alterations in gene expression regulation and thus lead to cancer. It is therefore important to characterize radiation-induced alterations in PTM patterns and the factors affecting them. A lymphoblastoid cell line established from a normal donor was used to screen for alterations in methylation levels at H3K4, H3K9, H3K27, and H4K20, as well as acetylation at H3K9, H3K56, H4K5, and H4K16, by quantitative Western Blot analysis at 15 min, 1 h and 24 h after irradiation with 2 Gy and 10 Gy. The variability of alterations in acetylation marks was in addition investigated in a panel of lymphoblastoid cell lines with differing radiosensitivity established from lung cancer patients. The screening procedure demonstrated consistent hypomethylation at H3K4me3 and hypoacetylation at all acetylation marks tested. In the panel of lymphoblastoid cell lines, however, a high degree of inter-individual variability became apparent. Radiosensitive cell lines showed more pronounced and longer lasting H4K16 hypoacetylation than radioresistant lines, which correlates with higher levels of residual γ-H2AX foci after 24 h. So far, the factors affecting extent and duration of radiation-induced histone alterations are poorly defined. The present work hints at a high degree of inter-individual variability and a potential correlation of DNA damage repair capacity and alterations in PTM levels

The U-line line balancing problem

NARCIS (Netherlands)

Miltenburg, G.J.; Wijngaard, J.

1994-01-01

The traditional line balancing (LB) problem considers a production line in which stations are arranged consecutively in a line. A balance is determined by grouping tasks into stations while moving forward (or backward) through a precedence network. Recently many production lines are being arranged

On the Origin of the Flare Emission in IRIS' SJI 2832 Filter: Balmer Continuum or Spectral Lines?

Czech Academy of Sciences Publication Activity Database

Kleint, L.; Heinzel, Petr; Krucker, S.

2017-01-01

Roč. 837, č. 2 (2017), 160/1-160/7 ISSN 0004-637X R&D Projects: GA ČR(CZ) GA16-18495S Institutional support: RVO:67985815 Keywords : Sun * chromosphere * flares Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 5.533, year: 2016

A search for magnetic fields in Lambda Bootis stars

International Nuclear Information System (INIS)

Bohlender, D.A.; Landstreet, J.D.

1990-01-01

We have searched a sample of λ Boo stars for magnetic fields similar to those observed in the magnetic Ap and Bp stars, using a Balmer-line Zeeman analyser. Apart from one dubious measurement, no fields are detected in our sample. It appears that magnetic fields of the λ Boo stars, if they exist, are significantly smaller than those found in magnetic upper main-sequence stars of similar spectral type; this conclusion is supported at about the 90 or 95 per cent confidence level by the present data. (author)

NuSTAR discovery of a luminosity dependent cyclotron line energy in Vela X-1

Energy Technology Data Exchange (ETDEWEB)

Fürst, Felix; Grefenstette, Brian W.; Harrison, Fiona; Madsen, Kristin K.; Walton, Dominic J. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Pottschmidt, Katja [Center for Space Science and Technology, University of Maryland Baltimore County, Baltimore, MD 21250 (United States); Wilms, Jörn [Dr. Karl-Remeis-Sternwarte and ECAP, Sternwartstr. 7, D-96049 Bamberg (Germany); Tomsick, John A.; Boggs, Steven E.; Craig, William W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Bachetti, Matteo [Université de Toulouse, UPS-OMP, IRAP, Toulouse (France); Christensen, Finn E. [DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Hailey, Charles J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Miller, Jon M. [Department of Astronomy, The University of Michigan, Ann Arbor, MI 48109 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Zhang, William [NASA Goddard Space Flight Center, Astrophysics Science Division, Code 662, Greenbelt, MD 20771 (United States)

2014-01-10

We present NuSTAR observations of Vela X-1, a persistent, yet highly variable, neutron star high-mass X-ray binary (HMXB). Two observations were taken at similar orbital phases but separated by nearly a year. They show very different 3-79 keV flux levels as well as strong variability during each observation, covering almost one order of magnitude in flux. These observations allow, for the first time ever, investigations on kilo-second time-scales of how the centroid energies of cyclotron resonant scattering features (CRSFs) depend on flux for a persistent HMXB. We find that the line energy of the harmonic CRSF is correlated with flux, as expected in the sub-critical accretion regime. We argue that Vela X-1 has a very narrow accretion column with a radius of around 0.4 km that sustains a Coulomb interaction dominated shock at the observed luminosities of L {sub x} ∼ 3 × 10{sup 36} erg s{sup –1}. Besides the prominent harmonic line at 55 keV the fundamental line around 25 keV is clearly detected. We find that the strengths of the two CRSFs are anti-correlated, which we explain by photon spawning. This anti-correlation is a possible explanation for the debate about the existence of the fundamental line. The ratio of the line energies is variable with time and deviates significantly from 2.0, also a possible consequence of photon spawning, which changes the shape of the line. During the second observation, Vela X-1 showed a short off-state in which the power-law softened and a cut-off was no longer measurable. It is likely that the source switched to a different accretion regime at these low mass accretion rates, explaining the drastic change in spectral shape.

Rooster semen cryopreservation: effect of pedigree line and male age on postthaw sperm function.

Science.gov (United States)

Long, J A; Bongalhardo, D C; Pelaéz, J; Saxena, S; Settar, P; O'Sullivan, N P; Fulton, J E

2010-05-01

The fertility rates of cryopreserved poultry semen are highly variable and not reliable for use in preservation of commercial genetic stocks. Our objective was to evaluate the cryosurvival of semen from 8 pedigreed layer lines at 2 different ages: the onset and end of commercial production. Semen from 160 roosters (20/line) was frozen individually with 11% glycerol at 6 and 12 mo of age. Glycerol was removed from thawed semen by Accudenz gradient centrifugation. The viability of thawed sperm from each male was determined using fluorescent live-dead staining and flow cytometry; sperm velocity parameters were measured using computerized motion analysis. The fertilizing ability of thawed sperm was evaluated in vitro by assessing hydrolysis of the inner perivitelline membrane. The postthaw function of sperm from the elite lines varied widely, despite the fact that fresh semen from all of these lines typically yielded high fertility rates. The percentage of thawed sperm with intact plasma membranes ranged from 27.8 + or - 2.1 to 49.6 + or - 1.9 and varied among lines and between age groups. Thawed sperm from 2 lines consistently demonstrated the highest and lowest motility parameters, whereas the velocity parameters of the remaining 6 lines varied widely. The mean number of hydrolysis points per square millimeter of inner perivitelline membrane ranged from 12.5 + or - 4.1 (line 2) to 103.3 + or - 30.2 (line 6). Age effects were observed for 4 out of 8 lines; however, improved postthaw sperm function at 12 mo of age was not consistent for all 3 assays. These results demonstrate variability among pedigreed lines in withstanding glycerol-based semen cryopreservation and provide a model for delineating genotypic and phenotypic factors affecting sperm cryosurvival.

Rooster Semen Cryopreservation: Effect of Pedigree Line and Male Age on Post-Thaw Sperm Function

Science.gov (United States)

The fertility rates of cryopreserved poultry semen are highly variable and not reliable for use in preservation of commercial genetic stocks. Our objective was to evaluate the cryosurvival of semen from 8 pedigreed layer lines at the onset and end of production. Semen from 160 roosters (20/line) was...

1RXS J180834.7+101041 is a new cataclysmic variable with non-uniform disc

Science.gov (United States)

Yakin, D. G.; Suleimanov, V. F.; Shimansky, V. V.; Borisov, N. V.; Bikmaev, I. F.; Sakhibullin, N. A.

2010-11-01

Results of photometric and spectroscopic investigations of the recently discovered disc cataclysmic variable star 1RXS J180834.7+101041 are presented. Emission spectra of the system show broad double peaked hydrogen and helium emission lines. Doppler maps for the hydrogen lines demonstrate strongly non-uniform emissivity distribution in the disc, similar to that found in IP Peg. It means that the system is a new cataclysmic variable with a spiral density wave in the disc. Masses of the components (MWD = 0.8+/-0.22 Msolar and MRD = 0.14+/-0.02 Msolar), and the orbit inclination (i = 78°+/- 1.°5) were estimated using the various well-known relations for cataclysmic variables.

Share-of-Surplus Product Line Optimisation with Price Levels

Directory of Open Access Journals (Sweden)

X. G. Luo

2014-01-01

Full Text Available Kraus and Yano (2003 established the share-of-surplus product line optimisation model and developed a heuristic procedure for this nonlinear mixed-integer optimisation model. In their model, price of a product is defined as a continuous decision variable. However, because product line optimisation is a planning process in the early stage of product development, pricing decisions usually are not very precise. In this research, a nonlinear integer programming share-of-surplus product line optimization model that allows the selection of candidate price levels for products is established. The model is further transformed into an equivalent linear mixed-integer optimisation model by applying linearisation techniques. Experimental results in different market scenarios show that the computation time of the transformed model is much less than that of the original model.

Iron and zinc availability in maize lines

Directory of Open Access Journals (Sweden)

Valéria Aparecida Vieira Queiroz

2011-09-01

Full Text Available The aim of this study was to characterize the Zn and Fe availability by phytic acid/Zn and phytic acid/Fe molar ratios, in 22 tropical maize inbred lines with different genetic backgrounds. The Zn and Fe levels were determined by atomic absorption spectrophotometry and the P through colorimetry method. Three screening methods for phytic acid (Phy analysis were tested and one, based on the 2,2'-bipyridine reaction, was select. There was significant variability in the contents of zinc (17.5 to 42 mg.kg-1, iron (12.2 to 36.7 mg.kg-1, phosphorus (230 to 400 mg.100 g-1, phytic acid (484 to 1056 mg.100 g-1, phytic acid P (140 to 293 mg.100 g-1 and available-P (43.5 to 199.5 mg.100 g-1, and in the available-P/total-P ratio (0.14 to 0.50, Phy/Zn (18.0 to 43.5 and Phy/Fe (16.3 to 45.5 molar ratios. Lines 560977, 560978 and 560982 had greater availability of Zn and lines 560975, 560977, 561010 and 5610111 showed better Fe availability. Lines 560975, 560977 and 560978 also showed better available-P/total-P ratio. Thus, the lines 560975, 560977 and 560978 were considered to have the potential for the development of cultivars of maize with high availability of Fe and/or Zn.

Characterization of selection effects on broiler lines using DNA fingerprinting

Directory of Open Access Journals (Sweden)

GS Schmidt

2003-05-01

Full Text Available The objective of this study was to evaluate the effect of selection for body weight on the genetic variability and diversity in broiler lines. Two paternal broiler lines (LL and LLc were used. LL line was selected for 12 generations for growth and carcass and reproduction characteristics. The LLc line was established from LL line in 1985 and mated at random. Blood samples from six chickens per line were collected and used for molecular analysis. Also, a DNA pool was made for each line to compare effects between lines. Data were analyzed considering the collected information on the presence or absence of DNA bands. Band sharing scores were calculated using the DICE coefficient. The pattern of the 21 most representative bands was used. DNA fingerprinting (DFP showed 90.48 % of polymorphism bands for both lines. Difference between lines was not due to the presence or absence of bands, but to the frequency of such bands in each genotype. Considering that both lines had the same genetic background, changes on band frequency were probably due to selection. Selection for body weight had an effect on the band frequency as evaluated by DFP, and for this reason this technique could be used as a tool in the selection process. Results also suggest that bands 4, 5 and 19 were linked to body weight traits, and bands 9, 10, 12, 13 and 21 were linked to reproductive traits such as egg production.

Seismic Response Analysis of Concrete Lining Structure in Large Underground Powerhouse

Directory of Open Access Journals (Sweden)

Xiaowei Wang

2017-01-01

Full Text Available Based on the dynamic damage constitutive model of concrete material and seismic rock-lining structure interaction analysis method, the seismic response of lining structure in large underground powerhouse is studied in this paper. In order to describe strain rate dependence and fatigue damage of concrete material under cyclic loading, a dynamic constitutive model for concrete lining considering tension and shear anisotropic damage is presented, and the evolution equations of damage variables are derived. The proposed model is of simple form and can be programmed into finite element procedure easily. In order to describe seismic interaction characteristics of the surrounding rock and lining, an explicit dynamic contact analysis method considering bond and damage characteristics of contact face between the surrounding rock and lining is proposed, and this method can integrate directly without iteration. The proposed method is applied to seismic stability calculation of Yingxiuwan Underground Powerhouse, results reveal that the amplitude and duration of input seismic wave determine the damage degree of lining structure, the damage zone of lining structure is mainly distributed in its arch, and the contact face damage has great influence on the stability of the lining structure.

Read margin analysis of crossbar arrays using the cell-variability-aware simulation method

Science.gov (United States)

Sun, Wookyung; Choi, Sujin; Shin, Hyungsoon

2018-02-01

This paper proposes a new concept of read margin analysis of crossbar arrays using cell-variability-aware simulation. The size of the crossbar array should be considered to predict the read margin characteristic of the crossbar array because the read margin depends on the number of word lines and bit lines. However, an excessively high-CPU time is required to simulate large arrays using a commercial circuit simulator. A variability-aware MATLAB simulator that considers independent variability sources is developed to analyze the characteristics of the read margin according to the array size. The developed MATLAB simulator provides an effective method for reducing the simulation time while maintaining the accuracy of the read margin estimation in the crossbar array. The simulation is also highly efficient in analyzing the characteristic of the crossbar memory array considering the statistical variations in the cell characteristics.

Risk Analysis Method Based on FMEA for Transmission Line in Lightning Hazards

Directory of Open Access Journals (Sweden)

You-Yuan WANG

2014-05-01

Full Text Available Failure rate of transmission line and reliability of power system are significantly affected by Lightning meteorological factor. In view of the complexity and variability of Lightning meteorological factors, this paper presents lightning trip-out rate model of transmission line in considering distribution of ground flash density and lightning day hours. Meanwhile, presents a failure rate model of transmission line in different condition, and a risk analysis method for transmission line considering multiple risk factors based on risk quantification. This method takes Lightning meteorological factor as the main evaluation standard, and establishes risk degree evaluation system for transmission line including another five evaluation standard. Put forward the risk indicators by quantify the risk factors based on experience date of transmission line in service. Based on the risk indexes comprehensive evaluation is conducted, and the evaluation result closer to practice is achieved, providing basis for transmission line risk warning and maintenance strategy. Through the risk analysis for 220 kV transmission line in a certain power supply bureau, the effectiveness of the proposed method is validated.

Center-to-Limb Variability of Hot Coronal EUV Emissions During Solar Flares

Science.gov (United States)

Thiemann, E. M. B.; Chamberlin, P. C.; Eparvier, F. G.; Epp, L.

2018-02-01

It is generally accepted that densities of quiet-Sun and active region plasma are sufficiently low to justify the optically thin approximation, and this is commonly used in the analysis of line emissions from plasma in the solar corona. However, the densities of solar flare loops are substantially higher, compromising the optically thin approximation. This study begins with a radiative transfer model that uses typical solar flare densities and geometries to show that hot coronal emission lines are not generally optically thin. Furthermore, the model demonstrates that the observed line intensity should exhibit center-to-limb variability (CTLV), with flares observed near the limb being dimmer than those occurring near disk center. The model predictions are validated with an analysis of over 200 flares observed by the EUV Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO), which uses six lines, with peak formation temperatures between 8.9 and 15.8 MK, to show that limb flares are systematically dimmer than disk-center flares. The data are then used to show that the electron column density along the line of sight typically increases by 1.76 × 10^{19} cm^{-2} for limb flares over the disk-center flare value. It is shown that the CTLV of hot coronal emissions reduces the amount of ionizing radiation propagating into the solar system, and it changes the relative intensities of lines and bands commonly used for spectral analysis.

Flaring radio lanterns along the ridge line: long-term oscillatory motion in the jet of S5 1803+784

Science.gov (United States)

Kun, E.; Karouzos, M.; Gabányi, K. É.; Britzen, S.; Kurtanidze, O. M.; Gergely, L. Á.

2018-04-01

We present a detailed analysis of 30 very long baseline interferometric observations of the BL Lac object S5 1803+784 (z = 0.679), obtained between mean observational time 1994.67 and 2012.91 at observational frequency 15 GHz. The long-term behaviour of the jet ridge line reveals the jet experiences an oscillatory motion superposed on its helical jet kinematics on a time-scale of about 6 years. The excess variance of the positional variability indicates the jet components being farther from the VLBI core have larger amplitude in their position variations. The fractional variability amplitude shows slight changes in 3-year bins of the component's position. The temporal variability in the Doppler boosting of the ridge line results in jet regions behaving as flaring "radio lanterns". We offer a qualitative scenario leading to the oscillation of the jet ridge line, that utilizes the orbital motion of the jet emitter black hole due to a binary black hole companion. A correlation analysis implies composite origin of the flux variability of the jet components, emerging due to possibly both the evolving jet-structure and its intrinsic variability.

Electron capture into the 3s, 3p, 3d states and the 3, 4, 5, 6 levels of H by proton impact on gases

International Nuclear Information System (INIS)

Lenormand, J.

1976-01-01

The excitation of the Hsub(α), Hsub(β), Hsub(γ), Hsub(delta) Balmer lines by means of 15-85keV protons incident on noble-gas and molecular targets have been observed. Absolute cross-sections for electron capture by the 3l (l=s, p, d) states and the 3, 4, 5, 6 levels of hydrogen atom have been determined with He, Ne, Ar, Kr, Xe, N 2 and O 2 . Polarizations of the Hsub(α) and Hsub(β) lines have been measured for 10-70keV protons on Ar, Kr, and Xe. Absolute cross-sections for the emission of the 3914A band of N 2 + have been obtained for 10-100keV protons on the gaseous nitrogen target [fr

Continuum emission in the 1980 July 1 solar flare

International Nuclear Information System (INIS)

Zirin, H.; Neidig, D.F.

1981-01-01

Comparison of continuum measurements of the 1980 July 1 flare at Big Bear Solar Observatory and Sacramento Peak Observatory show strong blue emission kernels with the ratio of Balmer continuum (Bac):lambda3862 continuum:continuum above 4275 A to be about 10:5:1. The blue continuum at 3862 A is too strong to be explained by unresolved lines. The Bac intensity was 2.5 times the photosphere and the strongest lambda3862 continuum was 2 times the photosphere. The brightest continuum kernel occurred late in the flare, after the hard X-ray peak and related in time to an isolated peak in the 2.2 MeV line, suggesting that the continuum was excited by protons above 20 MeV

Modeling a multivariable reactor and on-line model predictive control.

Science.gov (United States)

Yu, D W; Yu, D L

2005-10-01

A nonlinear first principle model is developed for a laboratory-scaled multivariable chemical reactor rig in this paper and the on-line model predictive control (MPC) is implemented to the rig. The reactor has three variables-temperature, pH, and dissolved oxygen with nonlinear dynamics-and is therefore used as a pilot system for the biochemical industry. A nonlinear discrete-time model is derived for each of the three output variables and their model parameters are estimated from the real data using an adaptive optimization method. The developed model is used in a nonlinear MPC scheme. An accurate multistep-ahead prediction is obtained for MPC, where the extended Kalman filter is used to estimate system unknown states. The on-line control is implemented and a satisfactory tracking performance is achieved. The MPC is compared with three decentralized PID controllers and the advantage of the nonlinear MPC over the PID is clearly shown.

Influence of the sagittal anatomy of the pelvis on the intercrestal line position.

Science.gov (United States)

Horduna, M; Legaye, J

2008-03-01

The line joining the two iliac crests is classically regarded as the anatomical landmark determining the inter-vertebral space L4-L5 for the spinal punctures. Its variability has been reported but never related to predictive clinical anatomic factors identifying patients groups in which there is increased risk of miscalculation of the spinal level. Two sagittal pelvic anatomical angles, called 'pelvic incidence' and 'pelvic lordosis' were measured on lateral X-rays of the pelvis of 132 normal individuals and 49 spondylolysis patients. The values were compared with the sagittal projection of the intercrestal line on the disco-vertebral lumbar structures. A strict relation was observed between this projection of the intercrestal line and the sagittal pelvic anatomical angles. The greater the pelvic incidence, the higher the intercrestal line was projected, all the more in patients with spondylolysis with a listhesis or a disc narrowing. The relation between the pelvic sagittal angles and the intercrestal line projection explains the variability described for this anatomical landmark. It implies precautions minimizing neurological risk in the case of a puncture carried out more cranially than expected, particularly for high values of pelvic incidence occurring in spinal pathologies such as spondylolysis, in the elderly or in the obese patients. In these cases, we recommend the use of spinal imaging during the procedure to assist selection of the desired insertion level.

Modelling and control algorithms of the cross conveyors line with multiengine variable speed drives

Science.gov (United States)

Cheremushkina, M. S.; Baburin, S. V.

2017-02-01

The paper deals with the actual problem of developing the control algorithm that meets the technical requirements of the mine belt conveyors, and enables energy and resource savings taking into account a random sort of traffic. The most effective method of solution of these tasks is the construction of control systems with the use of variable speed drives for asynchronous motors. The authors designed the mathematical model of the system ‘variable speed multiengine drive - conveyor - control system of conveyors’ that takes into account the dynamic processes occurring in the elements of the transport system, provides an assessment of the energy efficiency of application the developed algorithms, which allows one to reduce the dynamic overload in the belt to 15-20%.

Study of the Variability of the Reflection Component in Seyfert 1 Galaxies: Connecting the Fe K Variability with the Compton Hump

Science.gov (United States)

Ponti, G.; Miniutti, G.; Malaguti, G.; Gallo, L.; Goldwurm, A.

2009-05-01

We present preliminary results of an ongoing project devoted to the study of the continuum and Fe K band variability in a sample of bright AGNs. These kind of studies may break the spectral degeneracy between the different absorption/emission models, allowing ``safe'' measurements of the disc and black hole properties from the broad line shapes. In fact, the Fe K band, alone, allows a first separation between the different components. Here we show the case of NGC 3783 which shows both a constant and a variable reflection component as well as strong ionized absorption. We show that a fundamental contribution will be given by Simbol-X that will allow to simultaneously measure not only the Fe K variability, but also the connected reflection hump variations.

A first-generation software product line for data acquisition systems in astronomy

Science.gov (United States)

López-Ruiz, J. C.; Heradio, Rubén; Cerrada Somolinos, José Antonio; Coz Fernandez, José Ramón; López Ramos, Pablo

2008-07-01

This article presents a case study on developing a software product line for data acquisition systems in astronomy based on the Exemplar Driven Development methodology and the Exemplar Flexibilization Language tool. The main strategies to build the software product line are based on the domain commonality and variability, the incremental scope and the use of existing artifacts. It consists on a lean methodology with little impact on the organization, suitable for small projects, which reduces product line start-up time. Software Product Lines focuses on creating a family of products instead of individual products. This approach has spectacular benefits on reducing the time to market, maintaining the know-how, reducing the development costs and increasing the quality of new products. The maintenance of the products is also enhanced since all the data acquisition systems share the same product line architecture.

Luminous and Variable Stars in M31 and M33. IV. Luminous Blue Variables, Candidate LBVs, B[e] Supergiants, and the Warm Hypergiants: How to Tell Them Apart

Energy Technology Data Exchange (ETDEWEB)

Humphreys, Roberta M.; Gordon, Michael S.; Hahn, David [Minnesota Institute for Astrophysics, 116 Church Street SE, University of Minnesota, Minneapolis, MN 55455 (United States); Martin, John C. [University of Illinois Springfield, Springfield, IL 62703 (United States); Weis, Kerstin, E-mail: roberta@umn.edu [Astronomical Institute, Ruhr-Universitaet Bochum (Germany)

2017-02-10

In this series of papers we have presented the results of a spectroscopic survey of luminous stars in the nearby spirals M31 and M33. Here, we present spectroscopy of 132 additional stars. Most have emission-line spectra, including luminous blue variables (LBVs) and candidate LBVs, Fe ii emission line stars, the B[e] supergiants, and the warm hypergiants. Many of these objects are spectroscopically similar and are often confused with each other. We examine their similarities and differences and propose the following guidelines that can be used to help distinguish these stars in future work. (1) The B[e] supergiants have emission lines of [O i] and [Fe ii] in their spectra. Most of the spectroscopically confirmed sgB[e] stars also have warm circumstellar dust in their spectral energy distributions (SEDs). (2) Confirmed LBVs do not have the [O i] emission lines in their spectra. Some LBVs have [Fe ii] emission lines, but not all. Their SEDs show free–free emission in the near-infrared but no evidence for warm dust . Their most important and defining characteristic is the S Dor-type variability. (3) The warm hypergiants spectroscopically resemble the LBVs in their dense wind state and the B[e] supergiants. However, they are very dusty. Some have [Fe ii] and [O i] emission in their spectra like the sgB[e] stars, but are distinguished by their A- and F-type absorption-line spectra. In contrast, the B[e] supergiant spectra have strong continua and few if any apparent absorption lines. Candidate LBVs should share the spectral characteristics of the confirmed LBVs with low outflow velocities and the lack of warm circumstellar dust.

Spectrophotometry of emission-line stars in the magellanic clouds

Science.gov (United States)

Bohannan, Bruce

1990-01-01

The strong emission lines in the most luminous stars in the Magellanic Clouds indicate that these stars have such strong stellar winds that their photospheres are so masked that optical absorption lines do not provide an accurate measure of photospheric conditions. In the research funded by this grant, temperatures and gravities of emission-line stars both in the Large (LMC) and Small Magellanic Clouds (SMC) have been measured by fitting of continuum ultraviolet-optical fluxes observed with IUE with theoretical model atmospheres. Preliminary results from this work formed a major part of an invited review 'The Distribution of Types of Luminous Blue Variables'. Interpretation of the IUE observations obtained in this grant and archive data were also included in a talk at the First Boulder-Munich Hot Stars Workshop. Final results of these studies are now being completed for publication in refereed journals.

Using real-time problem solving to eliminate central line infections.

Science.gov (United States)

Shannon, Richard P; Frndak, Diane; Grunden, Naida; Lloyd, Jon C; Herbert, Cheryl; Patel, Bhavin; Cummins, Daniel; Shannon, Alexander H; O'Neill, Paul H; Spear, Steven J

2006-09-01

An estimated 200,000 Americans suffer central line-associated bloodstream infections (CLABs) each year, with 15%-20% mortality. Two intensive care units (ICUs) redefined the processes of care through system redesign to deliver reliable outcomes free of the variations that created the breeding ground for infection. The ICUs, comprising 28 beds at Allegheny General Hospital, employed the principles of the Toyota Production System adapted to health care--Perfecting Patient Care--and applied them to central line placement and maintenance. Intensive observations, which revealed multiple variances from established practices, and root cause analyses of all CLABs empowered the workers to implement countermeasures designed to eliminate the defects in the processes of central line placement and maintenance. New processes were implemented within 90 days. Within a year CLABs decreased from 49 to 6 (10.5 to 1.2 infections/1,000 line-days), and mortalities from 19 to 1 (51% to 16%), despite an increase in the use of central lines and number of line-days. These results were sustained during a 34-month period. CLABs are not an inevitable product of complex ICU care but the result of highly variable and therefore unreliable care delivery that predisposes to infection.

Security warning method and system for worker safety during live-line working

Science.gov (United States)

Jiang, Chilong; Zou, Dehua; Long, Chenhai; Yang, Miao; Zhang, Zhanlong; Mei, Daojun

2017-09-01

Live-line working is an essential part in the operations in an electric power system. Live-line workers are required to wear shielding clothing. Shielding clothing, however, acts as a closed environment for the human body. Working in a closed environment for a long time can change the physiological responses of the body and even endanger personal safety. According to the typical conditions of live-line working, this study synthesizes environmental factors related to shielding clothing and the physiological factors of the body to establish the heart rate variability index RMSSD and the comprehensive security warning index SWI. On the basis of both indices, this paper proposes a security warning method and system for the safety live-line workers. The system can monitor the real-time status of workers during live-line working to provide security warning and facilitate the effective safety supervision by the live operation center during actual live-line working.

The Correlation of Smile Line with the Vertical Cephalometric Parameters of Anterior Facial Height

Directory of Open Access Journals (Sweden)

T. Hosseinzadeh–Nik

2005-03-01

Full Text Available Statement of the problem: In the evolution of orthodontics, the changes in soft tissue,especially smile line attracts considerable attention.Purpose: The present study was carried out to evaluate the correlation of the smile line with the vertical parameters of anterior part of face.Materials and Methods: Forty-six Iranian adults, aged between 18-25 years were selected. Five quantitative and three qualitative variables of smile analysis were recorded for each subject. Cephalometric analysis was carried out using angular and linear parameters. The correlations between smile line variables and cephalometric parameters were calculated using Spearman and Pearson’s correlation analyses.Results: The result of this study showed that the cephalometric parameters of N-Me,Pn-Line, N-B, N-Pg had significant correlations with quantitative variable of toothlower lip position. The P-values were P=0.003, P=0.027, P=0.006, P=0.002 respectively. N-Me, N-B, N-Pg represented significant correlations with interlabial gapon smile (P= 0.006, P=0.036, P=0.002 respectively. There was a significant correlation between N-Pg and quantitative factor of tooth-upper lip position (P=0.034. Upper incisor to palatal plane showed a significant correlation with qualitative variable oftooth-upper lip position (P=0.019, interlabial gap on smile (P=0.004, and tooth-upper lip position (P=0.006. Upper incisor to FH represented a reverse relation with incisal edge to lower lip (P=0.028.This parameter also showed significant correlations withquantitative factors of tooth-lower lip position (P=0.040 and crown height (P=0.002.Conclusions: According to the results of this study, it can be concluded that, linear skeletal and dental vertical factors affect the vertical features of smile. Angular vertical parameters, except gonial angle, influence the vertical position of smile.

The interacting binary β Lyr. III

International Nuclear Information System (INIS)

Dimitrov, D.L.; Kubat, J.

1988-01-01

The results are presented of a non-LTE treatment of 24 He I lines based on a model atmosphere for β Lyr primary. The effects of an increased helium abundance on the departure coefficients (b-factors) and equivalent widths of the He I lines as well as on the equivalent widths of the Balmer lines are discussed. Apart from the already established fact that departures from LTE upon equivalent widths become increasingly important for longer wavelengths, it was also found that an increase in He abundance leads to a decrease in the non-LTE to LTE widths ratio, i.e. a reduction in the non-LTE effects upon equivalent widths of He I lines in a helium-rich atmosphere (although the b-factors are increasing). The influence of circumstellar matter on some spectral features is clearly evident, suggesting their origin in layers with lower densities and temperatures. (author). 19 figs., 3 tabs., 14 refs

Heterosis and Combining Ability of Drought-Tolerant Maize Lines for ...

African Journals Online (AJOL)

In drought prone areas of Ethiopia, maize is produced by small-scale farmers' where additional inputs are rarely applied. Although genetic tolerance is recommended for moisture stress, there is limited information on drought-tolerant genotypes reaction to variable environments. In this study, eight drought tolerant lines and ...

THE MICRO-ARCSECOND SCINTILLATION-INDUCED VARIABILITY (MASIV) SURVEY. III. OPTICAL IDENTIFICATIONS AND NEW REDSHIFTS

Energy Technology Data Exchange (ETDEWEB)

Pursimo, Tapio [Nordic Optical Telescope, Apartado 474, 38700 Santa Cruz de La Palma (Spain); Ojha, Roopesh [NVI Inc./U. S. Naval Observatory, 3450 Massachusetts Ave NW, Washington DC (United States); Jauncey, David L. [CSIRO Astronomy and Space Science and Mount Stromlo Observatory, Canberra ACT 0200 (Australia); Rickett, Barney J. [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Dutka, Michael S. [The Catholic University of America, 620 Michigan Ave., N.E., Washington DC 20064 (United States); Koay, Jun Yi; Bignall, Hayley E.; Macquart, Jean-Pierre [ICRAR, Curtin University, Bentley, WA 6845 (Australia); Lovell, James E. J. [School of Mathematics and Physics, University of Tasmania, TAS 7001 (Australia); Kedziora-Chudczer, Lucyna, E-mail: tpursimo@not.iac.es [School of Physics and Astrophysics, UNSW, Sydney NSW 2052 (Australia)

2013-04-10

Intraday variability (IDV) of the radio emission from active galactic nuclei is now known to be predominantly due to interstellar scintillation (ISS). The MASIV (The Micro-Arcsecond Scintillation-Induced Variability) survey of 443 flat spectrum sources revealed that the IDV is related to the radio flux density and redshift. A study of the physical properties of these sources has been severely handicapped by the absence of reliable redshift measurements for many of these objects. This paper presents 79 new redshifts and a critical evaluation of 233 redshifts obtained from the literature. We classify spectroscopic identifications based on emission line properties, finding that 78% of the sources have broad emission lines and are mainly FSRQs. About 16% are weak lined objects, chiefly BL Lacs, and the remaining 6% are narrow line objects. The gross properties (redshift, spectroscopic class) of the MASIV sample are similar to those of other blazar surveys. However, the extreme compactness implied by ISS favors FSRQs and BL Lacs in the MASIV sample as these are the most compact object classes. We confirm that the level of IDV depends on the 5 GHz flux density for all optical spectral types. We find that BL Lac objects tend to be more variable than broad line quasars. The level of ISS decreases substantially above a redshift of about two. The decrease is found to be generally consistent with ISS expected for beamed emission from a jet that is limited to a fixed maximum brightness temperature in the source rest frame.

State variables applied in the analysis of transmission lines considering the influence of frequency on the longitudinal parameters; Variaveis de estado aplicadas na analise de linhas de transmissao considerando a influencia da frequencia nos parametros longitudinais

Energy Technology Data Exchange (ETDEWEB)

Monzani, R.C. [Universidade Estadual de Londrina (UEL), PR (Brazil). Centro de Tecnologia e Urbanismo. Dept. de Engenharia Eletrica; Prado, A.J.; Kurokawa, S.; Bovolato, L.F. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Ilha Solteira, SP (Brazil). Fac. de Engenharia. Dept. de Engenharia Eletrica; Pissolato Filho, J. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Eletrica e Computacao. Dept. de Sistemas e Controle de Energia

2009-07-01

This paper presents a mathematical model to simulate and analyze time-domain electromagnetic transients in a transmission line using a single-phase representation of these lines with and without the influence of frequency on the longitudinal parameters. For this {pi} circuits and state variables are used to compose a linear system which is solved by a numerical routine. This routine is applied to the mathematical tool MatLab {sup TM} The aim of this paper is to demonstrate quickly and efficiently the study of electromagnetic waves to graduate students in Electrical Engineering, Computing and Mathematics courses, because EMTP (Electromagnetic Transient Program ) involve a greater complexity in handling which and can often lead disinterest in these individuals.

Variability of breath condensate pH may contribute to the better understanding of non-allergic seasonal respiratory diseases

Science.gov (United States)

Kullmann, Tamás; Szipőcs, Annamária

2017-09-01

The seasonal variability of certain non-allergic respiratory diseases is not clearly understood. Analysis of the breath condensate, the liquid that can be collected by breathing into a cold tube, has been proposed to bring closer to the understanding of airway pathologies. It has been assumed, that (1) airway lining fluid was a stable body liquid and (2) the breath condensate samples were representative of the airway lining fluid. Research was focussed on the identification of biomarkers indicative of respiratory pathologies. Despite 30 years of extended investigations breath condensate analysis has not gained any clinical implementation so far. The pH of the condensate is the characteristic that can be determined with the highest reproducibility. The present paper shows, that contrary to the initial assumptions, breath condensate is not a representative of the airway lining fluid, and the airway lining fluid is not a stable body liquid. Condensate pH shows baseline variability and it is influenced by drinking and by the ambient temperature. The changes in condensate pH are linked to changes in airway lining fluid pH. The variability of airway lining fluid pH may explain seasonal incidence of certain non-allergic respiratory diseases such as the catching of a common cold and the increased incidence of COPD exacerbations and exercise-induced bronchoconstriction in cold periods.

Radiation sensitivity of Merkel cell carcinoma cell lines

Energy Technology Data Exchange (ETDEWEB)

Leonard, J.H.; Ramsay, J.R.; Birrell, G.W. [Queensland Institute of Medical Research (Australia)] [and others

1995-07-30

Merkel cell carcinoma (MCC), being a small cell carcinoma, would be expected to be sensitive to radiation. Clinical analysis of patients at our center, especially those with macroscopic disease, would suggest the response is quite variable. We have recently established a number of MCC cell lines from patients prior to radiotherapy, and for the first time are in a position to determine their sensitivity under controlled conditions. Some of the MCC lines grew as suspension cultures and could not be single cell cloned; therefore, it was not possible to use clonogenic survival for all cell lines. A tetrazolium based (MTT) assay was used for these lines, to estimate cell growth after {gamma} irradiation. Control experiments were conducted on lymphoblastoid cell lines (LCL) and the adherent MCC line, MCC13, to demonstrate that the two assays were comparable under the conditions used. We have examined cell lines from MCC, small cell lung cancer (SCLC), malignant melanomas, Epstein Barr virus (EBV) transformed lymphocytes (LCL), and skin fibroblasts for their sensitivity to {gamma} irradiation using both clonogenic cell survival and MTT assays. The results show that the tumor cell lines have a range of sensitivities, with melanoma being more resistant (surviving fraction at 2 Gy (SF2) 0.57 and 0.56) than the small cell carcinoma lines, MCC (SF2 range 0.21-0.45, mean SF2 0.30, n = 8) and SCLC (SF2 0.31). Fibroblasts were the most sensitive (SF2 0.13-0.20, mean 0.16, n = 5). The MTT assay, when compared to clonogenic assay for the MCC13 adherent line and the LCL, gave comparable results under the conditions used. Both assays gave a range of SF2 values for the MCC cell lines, suggesting that these cancers would give a heterogeneous response in vivo. The results with the two derivative clones of MCC14 (SF2 for MCC14/1 0.38, MCC14/2 0.45) would further suggest that some of them may develop resistance during clonogenic evolution. 25 refs., 3 figs., 1 tab.

Radiation sensitivity of Merkell cell carcinoma cell lines

International Nuclear Information System (INIS)

Leonard, J. Helen; Ramsay, Jonathan R.; Kearsley, John H.; Birrell, Geoff W.

1995-01-01

Purpose: Merkel cell carcinoma (MCC), being a small cell carcinoma, would be expected to be sensitive to radiation. Clinical analysis of patients at our center, especially those with macroscopic disease, would suggest the response is quite variable. We have recently established a number of MCC cell lines from patients prior to radiotherapy, and for the first time are in a position to determine their sensitivity under controlled conditions. Methods and Materials: Some of the MCC lines grew as suspension cultures and could not be single cell cloned; therefore, it was not possible to use clonogenic survival for all cell lines. A tetrazolium based (MTT) assay was used for these lines, to estimate cell growth after γ irradiation. Control experiments were conducted on lymphoblastoid cell lines (LCL) and the adherent MCC line, MCC13, to demonstrate that the two assays were comparable under the conditions used. Results: We have examined cell lines from MCC, small cell lung cancer (SCLC), malignant melanomas, Epstein Barr virus (EBV) transformed lymphocytes (LCL), and skin fibroblasts for their sensitivity to γ irradiation using both clonogenic cell survival and MTT assays. The results show that the tumor cell lines have a range of sensitivities, with melanoma being more resistant (surviving fraction at 2 Gy (SF2) 0.57 and 0.56) than the small cell carcinoma lines, MCC (SF2 range 0.21-0.45, mean SF2 0.30, n = 8) and SCLC (SF2 0.31). Fibroblasts were the most sensitive (SF2 0.13-0.20, mean 0.16, n = 5). The MTT assay, when compared to clonogenic assay for the MCC13 adherent line and the LCL, gave comparable results under the conditions used. Conclusion: Both assays gave a range of SF2 values for the MCC cell lines, suggesting that these cancers would give a heterogeneous response in vivo. The results with the two derivative clones of MCC14 (SF2 for MCC14/1 0.38, MCC14/2 0.45) would further suggest that some of them may develop resistance during clonogenic evolution

Galactic water vapor emission: further observations of variability.

Science.gov (United States)

Knowles, S H; Mayer, C H; Sullivan, W T; Cheung, A C

1969-10-10

Recent observations of the 1.35-centimeter line emission of water vapor from galactic sources show short-term variability in the spectra of several sources. Two additional sources, Cygnus 1 and NGC 6334N, have been observed, and the spectra of W49 and VY Canis Majoris were measured over a wider range of radial velocity.

THE LICK AGN MONITORING PROJECT 2011: SPECTROSCOPIC CAMPAIGN AND EMISSION-LINE LIGHT CURVES

Energy Technology Data Exchange (ETDEWEB)

Barth, Aaron J. [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA, 92697-4575 (United States); Bennert, Vardha N. [Physics Department, California Polytechnic State University, San Luis Obispo, CA 93407 (United States); Canalizo, Gabriela [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Filippenko, Alexei V.; Li, Weidong [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Gates, Elinor L. [Lick Observatory, P.O. Box 85, Mount Hamilton, CA 95140 (United States); Greene, Jenny E. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Malkan, Matthew A.; Treu, Tommaso [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States); Pancoast, Anna [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Sand, David J. [Texas Tech University, Physics Department, Box 41051, Lubbock, TX 79409-1051 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Boulevard, Pasadena, CA 91109 (United States); Woo, Jong-Hak [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Assef, Roberto J. [Núcleo de Astronomía de la Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército Libertador 441, Santiago (Chile); Bae, Hyun-Jin [Department of Astronomy and Center for Galaxy Evolution Research, Yonsei University, Seoul 120-749 (Korea, Republic of); Brewer, Brendon J. [Department of Statistics, The University of Auckland, Private Bag 92019, Auckland 1142 (New Zealand); Cenko, S. Bradley [Astrophysics Science Division, NASA Goddard Space Flight Center, MC 661, Greenbelt, MD 20771 (United States); and others

2015-04-15

In the Spring of 2011 we carried out a 2.5 month reverberation mapping campaign using the 3 m Shane telescope at Lick Observatory, monitoring 15 low-redshift Seyfert 1 galaxies. This paper describes the observations, reductions and measurements, and data products from the spectroscopic campaign. The reduced spectra were fitted with a multicomponent model in order to isolate the contributions of various continuum and emission-line components. We present light curves of broad emission lines and the active galactic nucleus (AGN) continuum, and measurements of the broad Hβ line widths in mean and rms spectra. For the most highly variable AGNs we also measured broad Hβ line widths and velocity centroids from the nightly spectra. In four AGNs exhibiting the highest variability amplitudes, we detect anticorrelations between broad Hβ width and luminosity, demonstrating that the broad-line region “breathes” on short timescales of days to weeks in response to continuum variations. We also find that broad Hβ velocity centroids can undergo substantial changes in response to continuum variations; in NGC 4593, the broad Hβ velocity shifted by ∼250 km s{sup −1} over a 1 month period. This reverberation-induced velocity shift effect is likely to contribute a significant source of confusion noise to binary black hole searches that use multi-epoch quasar spectroscopy to detect binary orbital motion. We also present results from simulations that examine biases that can occur in measurement of broad-line widths from rms spectra due to the contributions of continuum variations and photon-counting noise.

ORIGIN OF THE GALACTIC DIFFUSE X-RAY EMISSION: IRON K-SHELL LINE DIAGNOSTICS

Energy Technology Data Exchange (ETDEWEB)

Nobukawa, Masayoshi [Department of Teacher Training and School Education, Nara University of Education, Takabatake-cho, Nara, 630-8528 (Japan); Uchiyama, Hideki [Faculty of Education, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529 (Japan); Nobukawa, Kumiko K.; Koyama, Katsuji [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwake-cho, Sakyo-ku, Kyoto, 606-8502 (Japan); Yamauchi, Shigeo, E-mail: nobukawa@nara-edu.ac.jp [Department of Physics, Nara Women’s University, Kitauoyanishimachi, Nara, 630-8506 (Japan)

2016-12-20

This paper reports detailed K-shell line profiles of iron (Fe) and nickel (Ni) of the Galactic Center X-ray Emission (GCXE), Galactic Bulge X-ray Emission (GBXE), Galactic Ridge X-ray Emission (GRXE), magnetic Cataclysmic Variables (mCVs), non-magnetic Cataclysmic Variables (non-mCVs), and coronally Active Binaries (ABs). For the study of the origin of the GCXE, GBXE, and GRXE, the spectral analysis is focused on equivalent widths of the Fe i-K α , Fe xxv-He α , and Fe xxvi-Ly α  lines. The global spectrum of the GBXE is reproduced by a combination of the mCVs, non-mCVs, and ABs spectra. On the other hand, the GRXE spectrum shows significant data excesses at the Fe i-K α and Fe xxv-He α  line energies. This means that additional components other than mCVs, non-mCVs, and ABs are required, which have symbiotic phenomena of cold gas and very high-temperature plasma. The GCXE spectrum shows larger excesses than those found in the GRXE spectrum at all the K-shell lines of iron and nickel. Among them the largest ones are the Fe i-K α , Fe xxv-He α , Fe xxvi-Ly α , and Fe xxvi-Ly β  lines. Together with the fact that the scale heights of the Fe i-K α , Fe xxv-He α , and Fe xxvi-Ly α lines are similar to that of the central molecular zone (CMZ), the excess components would be related to high-energy activity in the extreme envelopment of the CMZ.

A Possibilistic Approach for the Prediction of the Risk of Interference between Power and Signal Lines Onboard Satellites

Directory of Open Access Journals (Sweden)

Nicola Toscani

2018-01-01

Full Text Available This work presents a hybrid random/fuzzy approach for uncertainty quantification in electromagnetic modelling, which combines probability and possibility theory in order to properly account for both aleatory and epistemic uncertainty, respectively. In particular, a typical intrasystem electromagnetic-compatibility problem in aerospace applications is considered, where some parameters are affected by fabrication tolerances or other kinds of randomness (aleatory uncertainty and others are inherently deterministic but unknown due to human’s lack of knowledge (epistemic uncertainty. Namely, a differential-signal line in a satellite is subject to crosstalk due to a nearby dc power line carrying conducted emissions generated by a dc-dc converter in a wide frequency range (up to 100 MHz. The nonideal features of the signal line (e.g., weak unbalance of terminal loads are treated as random variables (RVs, whereas the mutual position of signal and power line is characterized by possibility theory through suitable fuzzy variables. Such a hybrid approach allows deriving a general and exhaustive description of uncertainty of the target variable of interest, that is, the differential noise voltage induced in the signal line. The obtained results are compared versus a conventional Monte Carlo simulation where all parameters are treated as RVs, and the advantages of the proposed approach (in terms of completeness and richness of information gained about sensitivity of results are highlighted.

Data presentation options to manage variability in physical activity research.

Science.gov (United States)

Valbuena, Diego; Miller, Bryon G; Samaha, Andrew L; Miltenberger, Raymond G

2017-07-01

This paper presents seven tactics for managing the variability evident in some physical activity data. High levels of variability in daily step-count data from pedometers or accelerometers can make typical visual inspection difficult. Therefore, the purpose of the current paper is to discuss several strategies that might facilitate the visual interpretation of highly variable data. The seven strategies discussed in this paper are phase mean and median lines, daily average per week, weekly cumulative, proportion of baseline, 7-day moving average, change point detection, and confidence intervals. We apply each strategy to a data set and discuss the advantages and disadvantages. © 2017 Society for the Experimental Analysis of Behavior.

Searching for intermediate-mass black holes via optical variability

Science.gov (United States)

Adler-Levine, Ryan; Moran, Edward C.; Kay, Laura

2018-01-01

A handful of nearby dwarf galaxies with intermediate-mass black holes (IMBHs) in their nuclei display significant optical variability on short timescales. To investigate whether dwarf galaxy AGNs as a class exhibit similar variability, we have monitored a sample of low-mass galaxies that possess spectroscopically confirmed type 1 AGNs. However, because of the variations in seeing, focus, and guiding errors that occur in images taken at different epochs, analyses based on aperture photometry are ineffective. We have thus developed a new method for matching point-spread functions in images that permits use of image subtraction photometry techniques. Applying this method to our photometric data, we have confirmed that several galaxies with IMBHs are indeed variable, which suggests that variability can be used to search for IMBHs in low-mass galaxies whose emission-line properties are ambiguous.

Object-Oriented Control System Design Using On-Line Training of Artificial Neural Networks

Science.gov (United States)

Rubaai, Ahmed

1997-01-01

This report deals with the object-oriented model development of a neuro-controller design for permanent magnet (PM) dc motor drives. The system under study is described as a collection of interacting objects. Each object module describes the object behaviors, called methods. The characteristics of the object are included in its variables. The knowledge of the object exists within its variables, and the performance is determined by its methods. This structure maps well to the real world objects that comprise the system being modeled. A dynamic learning architecture that possesses the capabilities of simultaneous on-line identification and control is incorporated to enforce constraints on connections and control the dynamics of the motor. The control action is implemented "on-line", in "real time" in such a way that the predicted trajectory follows a specified reference model. A design example of controlling a PM dc motor drive on-line shows the effectiveness of the design tool. This will therefore be very useful in aerospace applications. It is expected to provide an innovative and noval software model for the rocket engine numerical simulator executive.

Culinary and nutritional quality of common bean lines with Carioca grain type and interaction with environments

Directory of Open Access Journals (Sweden)

Helton Santos Pereira

Full Text Available ABSTRACT The objectives of this work were to study the genetic variability and the interaction between genotypes and environments for cooking time and protein content of bean grains as well as to identify elite lines of Carioca grain type with short cooking time, high protein content and high adaptability and stability for these two traits. Sixteen experiments were conducted in a complete randomized block design with three replications during the rainy, dry and winter seasons, in Goiás, Distrito Federal, Pernambuco, Sergipe, Bahia and Paraná States, in 2009 and 2010. Each trial was composed by 16 elite lines of Carioca grain type and the data of cooking time and protein content were obtained. Data were submitted to analysis of variance and to stability and adaptability analysis, according to the methodology proposed by Annichiarico. Genetic variability was found for cooking time and for protein content among Carioca common bean elite lines; however, for protein content this variability is lower. The environmental effect is important for the expression of these traits and is larger than the genetic effect. The interaction between genotypes and environments is important for cooking time and for protein content of common beans. The lines CNFC 11951 and CNFC 11962 presents short cooking time, high protein content and high stability and adaptability for both traits.

Analytical, Practical and Emotional Intelligence and Line Manager Competencies

Directory of Open Access Journals (Sweden)

Anna Baczyńska

2015-12-01

Full Text Available Purpose: The research objective was to examine to what extent line manager competencies are linked to intelligence, and more specifically, three types of intelligence: analytical (fluid, practical and emotional. Methodology: The research was carried out with line managers (N=98 who took part in 12 Assessment Centre sessions and completed tests measuring analytical, practical and emotional intelligence. The adopted hypotheses were tested using a multiple regression. In the regression model, the dependent variable was a managerial competency (management and striving for results, social skills, openness to change, problem solving, employee development and the explanatory variables were the three types of intelligence. Five models, each for a separate management competency, were tested in this way. Findings: In the study, it was hypothesized that practical intelligence relates to procedural tacit knowledge and is the strongest indicator of managerial competency. Analysis of the study results testing this hypothesis indicated that practical intelligence largely accounts for the level of competency used in managerial work (from 21% to 38%. The study findings suggest that practical intelligence is a better indicator of managerial competencies among line managers than traditionally measured IQ or emotional intelligence. Originality: This research fills an important gap in the literature on the subject, indicating the links between major contemporary selection indicators (i.e., analytical, practical and emotional intelligence and managerial competencies presented in realistic work simulations measured using the Assessment Centre process.

The optical variability of SDSS quasars from multi-epoch spectroscopy. I. Results from 60 quasars with ≥ six-epoch spectra

Energy Technology Data Exchange (ETDEWEB)

Guo, Hengxiao; Gu, Minfeng, E-mail: hxguo@shao.ac.cn, E-mail: gumf@shao.ac.cn [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China)

2014-09-01

In a sample of 60 quasars selected from the Sloan Digital Sky Survey with at least six-epoch spectroscopy, we investigate the variability of emission lines and continuum luminosity at various aspects. A strong anti-correlation between the variability and continuum luminosity at 2500 Å is found for the sample, which is consistent with previous works. In individual sources, we find that half of the sample objects follow the trend of being bluer when brighter, while the remaining half follow the redder-when-brighter (RWB) trend. Although the mechanism for RWB is unclear, the effects of host galaxy contribution due to seeing variations cannot be completely ruled out. As expected from the photoionization model, the positive correlations between the broad emission line and continuum luminosity are found in most individual sources, as well as for the whole sample. We confirm the Baldwin effect in most individual objects and the whole sample, while a negative Baldwin effect is also found in several quasars, which can be at least partly (if not all) due to the host galaxy contamination. We find positive correlations between the broad emission line luminosity and line width in most individual quasars, as well as the whole sample, implying a line base that is more variable than the line core.

Dust Attenuation and H(alpha) Star Formation Rates of Z Approx. 0.5 Galaxies

Science.gov (United States)

Ly, Chun; Malkan, Matthew A.; Kashikawa, Nobunari; Ota, Kazuaki; Shimasaku, Kazuhiro; Iye, Masanori; Currie, Thayne

2012-01-01

Using deep narrow-band and broad-band imaging, we identify 401 z approximately 0.40 and 249 z approximately 0.49 H-alpha line-emitting galaxies in the Subaru Deep Field. Compared to other H-alpha surveys at similar redshifts, our samples are unique since they probe lower H-alpha luminosities, are augmented with multi-wavelength (rest-frame 1000AA--1.5 microns) coverage, and a large fraction (20%) of our samples has already been spectroscopically confirmed. Our spectra allow us to measure the Balmer decrement for nearly 60 galaxies with H-beta detected above 5-sigma. The Balmer decrements indicate an average extinction of A(H-alpha)=0.7(uparrow){+1.4}_{-0.7} mag. We find that the Balmer decrement systematically increases with higher H-alpha luminosities and with larger stellar masses, in agreement with previous studies with sparser samples. We find that the SFRs estimated from modeling the spectral energy distribution (SED) is reliable---we derived an "intrinsic" H-alpha luminosity which is then reddened assuming the color excess from SED modeling. The SED-predicted H-alpha luminosity agrees with H-alpha narrow-band measurements over 3 dex (rms of 0.25 dex). We then use the SED SFRs to test different statistically-based dust corrections for H-alpha and find that adopting one magnitude of extinction is inappropriate: galaxies with lower luminosities are less reddened. We find that the luminosity-dependent dust correction of Hopkins et al. yields consistent results over 3 dex (rms of 0.3 dex). Our comparisons are only possible by assuming that stellar reddening is roughly half of nebular reddening. The strong correspondence argue that with SED modeling, we can derive reliable intrinsic SFRs even in the absence of H-alpha measurements at z approximately 0.5.

Response of wheat restricted-tillering and vigorous growth traits to variables of climate change.

Science.gov (United States)

Dias de Oliveira, Eduardo A; Siddique, Kadambot H M; Bramley, Helen; Stefanova, Katia; Palta, Jairo A

2015-02-01

The response of wheat to the variables of climate change includes elevated CO2, high temperature, and drought which vary according to the levels of each variable and genotype. Independently, elevated CO2, high temperature, and terminal drought affect wheat biomass and grain yield, but the interactive effects of these three variables are not well known. The aim of this study was to determine the effects of elevated CO2 when combined with high temperature and terminal drought on the high-yielding traits of restricted-tillering and vigorous growth. It was hypothesized that elevated CO2 alone, rather than combined with high temperature, ameliorates the effects of terminal drought on wheat biomass and grain yield. It was also hypothesized that wheat genotypes with more sink capacity (e.g. high-tillering capacity and leaf area) have more grain yield under combined elevated CO2, high temperature, and terminal drought. Two pairs of sister lines with contrasting tillering and vigorous growth were grown in poly-tunnels in a four-factor completely randomized split-plot design with elevated CO2 (700 µL L(-1)), high day time temperature (3 °C above ambient), and drought (induced from anthesis) in all combinations to test whether elevated CO2 ameliorates the effects of high temperature and terminal drought on biomass accumulation and grain yield. For biomass and grain yield, only main effects for climate change variables were significant. Elevated CO2 significantly increased grain yield by 24-35% in all four lines and terminal drought significantly reduced grain yield by 16-17% in all four lines, while high temperature (3 °C above the ambient) had no significant effect. A trade-off between yield components limited grain yield in lines with greater sink capacity (free-tillering lines). This response suggests that any positive response to predicted changes in climate will not overcome the limitations imposed by the trade-off in yield components. © 2014 Commonwealth of

Backprojection filtering for variable orbit fan-beam tomography

International Nuclear Information System (INIS)

Gullberg, G.T.; Zeng, G.L.

1995-01-01

Backprojection filtering algorithms are presented for three variable Orbit fan-beam geometries. Expressions for the fan beam projection and backprojection operators are given for a flat detector fan-beam geometry with fixed focal length, with variable focal length, and with fixed focal length and off-center focusing. Backprojection operators are derived for each geometry using transformation of coordinates to transform from a parallel geometry backprojector to a fan-beam backprojector for the appropriate geometry. The backprojection operator includes a factor which is a function of the coordinates of the projection ray and the coordinates of the pixel in the backprojected image. The backprojection filtering algorithm first backprojects the variable orbit fan-beam projection data using the appropriately derived backprojector to obtain a 1/r blurring of the original image then takes the two-dimensional (2D) Fast Fourier Transform (FFT) of the backprojected image, then multiples the transformed image by the 2D ramp filter function, and finally takes the inverse 2D FFT to obtain the reconstructed image. Computer simulations verify that backprojectors with appropriate weighting give artifact free reconstructions of simulated line integral projections. Also, it is shown that it is not necessary to assume a projection model of line integrals, but the projector and backprojector can be defined to model the physics of the imaging detection process. A backprojector for variable orbit fan-beam tomography with fixed focal length is derived which includes an additional factor which is a function of the flux density along the flat detector. It is shown that the impulse response for the composite of the projection and backprojection operations is equal to 1/r

X-shooter spectroscopy of young stellar objects in Lupus. Atmospheric parameters, membership, and activity diagnostics

Science.gov (United States)

Frasca, A.; Biazzo, K.; Alcalá, J. M.; Manara, C. F.; Stelzer, B.; Covino, E.; Antoniucci, S.

2017-06-01

Aims: A homogeneous determination of basic stellar parameters of young stellar object (YSO) candidates is needed to confirm their pre-main sequence evolutionary stage and membership to star forming regions (SFRs), and to get reliable values of the quantities related to chromospheric activity and accretion. Methods: We used the code ROTFIT and synthetic BT-Settl spectra for the determination of the atmospheric parameters (Teff and log g), veiling (r), radial (RV), and projected rotational velocity (vsini) from X-shooter spectra of 102 YSO candidates (95 of infrared Class II and seven Class III) in the Lupus SFR. The spectral subtraction of inactive templates, rotationally broadened to match the vsini of the targets, enabled us to measure the line fluxes for several diagnostics of both chromospheric activity and accretion, such as Hα, Hβ, Ca II, and Na I lines. Results: We have shown that 13 candidates can be rejected as Lupus members based on their discrepant RV with respect to Lupus and/or the very low log g values. At least 11 of them are background giants, two of which turned out to be lithium-rich giants. Regarding the members, we found that all Class III sources have Hα fluxes that are compatible with a pure chromospheric activity, while objects with disks lie mostly above the boundary between chromospheres and accretion. Young stellar objects with transitional disks display both high and low Hα fluxes. We found that the line fluxes per unit surface are tightly correlated with the accretion luminosity (Lacc) derived from the Balmer continuum excess. This rules out that the relationships between Lacc and line luminosities found in previous works are simply due to calibration effects. We also found that the Ca II-IRT flux ratio, FCaII8542/FCaII8498, is always small, indicating an optically thick emission source. The latter can be identified with the accretion shock near the stellar photosphere. The Balmer decrement reaches instead, for several accretors, high

Atomic emission spectroscopy for the on-line monitoring of incineration processes

NARCIS (Netherlands)

Timmermans, E.A.H.; de Groote, F.P.J.; Jonkers, J.; Gamero, A.; Sola, A.; Mullen, van der J.J.A.M.

2003-01-01

A diagnostic measurement system based on atomic emission spectroscopy has been developed for the purpose of on-line monitoring of hazardous elements in industrial combustion gases. The aim was to construct a setup with a high durability for rough and variable experimental conditions, e.g. a strongly

Long-slit optical spectroscopy of powerful far-infrared galaxies - The nature of the nuclear energy source

Science.gov (United States)

Armus, Lee; Heckman, Timothy M.; Miley, George K.

1989-01-01

Optical spectroscopic data are presented for a sample of 47 powerful far-IR galaxies chosen for IR spectral shape, and for six other IR-bright galaxies. The stellar absorption lines expected from a population of old stars are generally very weak in the nuclei of the galaxies. Very weak Mg I absorption is found in regions well off the nucleus, implying that the visible spectrum is dominated by young stars and not by an AGN. At least one, and probably five, of the galaxies have detectable WR emission features, providing additional evidence for a young stellar population. About 20 percent of the galaxies have strong Balmer absorption lines, indicating the presence of a substantial intermediate-age stellar population. The equivalent width of the H-alpha emission line can be modeled as arising from a mixture of a large young population and an intermediate-age population of stars.

White-dwarf rotational equilibria in magnetic cataclysmic variable stars

Energy Technology Data Exchange (ETDEWEB)

Warner, B. (Cape Town Univ. (South Africa). Dept. of Astronomy Australian National Univ., Canberra (Australia). Dept. of Mathematics); Wickramasinghe, D.T. (Australian National Univ., Canberra (Australia). Dept. of Mathematics)

1991-02-01

The magnetic cataclysmic variable stars (polars, intermediate polars and DQ Her stars) are grouped about three lines in the orbital period-spin period diagram. This segregation is shown to be the consequence of competition between braking and accretion torques when combined with the effects of cyclical variations in rate of mass transfer. (author).

Further observations of the lambda 10830 He line in stars and their significance as a measure of stellar activity

International Nuclear Information System (INIS)

Zirin, H.

1975-11-01

Measurements of the lambda 10830 He line in 198 stars are given along with data on other features in that spectral range. Nearly 80% of all G and K stars show some lambda 10830; of these, half are variable and 1/4 show emission. It was confirmed that lambda 10830 is not found in M stars, is weak in F stars, and is particularly strong in close binaries. The line is found in emission in extremely late M and S stars, along with P gamma, but P gamma is not in emission in G and K stars with lambda 10830 emissions. Variable He emission and Ti I emission are found in the RV Tauri variables R Scuti and U Mon. In R Aqr the Fe XIII coronal line lambda 10747 and a line at lambda 11012, which may be singlet He or La II, are found, as well as lambda 10830 and P gamma. The nature of coronas or hot chromospheres in the various stars is discussed. It was concluded that the lambda 10830 intensity must be more or less proportional to the energy deposited in the chromosphere corona by non-thermal processes

On-line scheme for parameter estimation of nonlinear lithium ion battery equivalent circuit models using the simplified refined instrumental variable method for a modified Wiener continuous-time model

International Nuclear Information System (INIS)

Allafi, Walid; Uddin, Kotub; Zhang, Cheng; Mazuir Raja Ahsan Sha, Raja; Marco, James

2017-01-01

Highlights: •Off-line estimation approach for continuous-time domain for non-invertible function. •Model reformulated to multi-input-single-output; nonlinearity described by sigmoid. •Method directly estimates parameters of nonlinear ECM from the measured-data. •Iterative on-line technique leads to smoother convergence. •The model is validated off-line and on-line using NCA battery. -- Abstract: The accuracy of identifying the parameters of models describing lithium ion batteries (LIBs) in typical battery management system (BMS) applications is critical to the estimation of key states such as the state of charge (SoC) and state of health (SoH). In applications such as electric vehicles (EVs) where LIBs are subjected to highly demanding cycles of operation and varying environmental conditions leading to non-trivial interactions of ageing stress factors, this identification is more challenging. This paper proposes an algorithm that directly estimates the parameters of a nonlinear battery model from measured input and output data in the continuous time-domain. The simplified refined instrumental variable method is extended to estimate the parameters of a Wiener model where there is no requirement for the nonlinear function to be invertible. To account for nonlinear battery dynamics, in this paper, the typical linear equivalent circuit model (ECM) is enhanced by a block-oriented Wiener configuration where the nonlinear memoryless block following the typical ECM is defined to be a sigmoid static nonlinearity. The nonlinear Weiner model is reformulated in the form of a multi-input, single-output linear model. This linear form allows the parameters of the nonlinear model to be estimated using any linear estimator such as the well-established least squares (LS) algorithm. In this paper, the recursive least square (RLS) method is adopted for online parameter estimation. The approach was validated on experimental data measured from an 18650-type Graphite

Hamiltonian theory of vacuum helical torus lines of magnetic force

International Nuclear Information System (INIS)

Gnudi, Giovanni; Hatori, Tadatsugu

1994-01-01

For making plasma into equilibrium state, the lines of magnetic force must have magnetic surfaces. However in a helical system, space is divided into the region having magnetic surface structure and the region that does not have it. Accordingly, it is an important basic research for the plasma confinement in a helical system to examine where is the boundary of both regions and how is the large area structure of the lines of magnetic force in the boundary region. The lines of magnetic force can be treated as a Hamilton mechanics system, and it has been proved that the Hamiltonian for the lines of magnetic force can be expressed by a set of canonical variables and the function of time. In this research, the Hamiltonian that describes the lines of magnetic force of helical system torus coordination in vacuum was successfully determined concretely. Next, the development of new linear symplectic integration method was carried out. The important supports for the theory of determining Hamiltonian are Lie transformation and paraxial expansion. The procedure is explained. In Appendix, Lie transformation, Hamiltonian for the lines of magnetic force, magnetic potential, Taylor expansion of the potential, cylindrical limit approximation, helical toroidal potential and integrable model are described. (K.I.)

Cataclysmic variables as probes of x-ray properties of interstellar grains

International Nuclear Information System (INIS)

Bode, M.F.; Evans, A.; Norwell, G.A.

1983-01-01

Interstellar-grain properties have previously been probed at wavelengths ranging from the infrared to the ultraviolet. Recent work by other authors has shown that we may also observe the effects of scattering by such grains at x-ray wavelengths. In this paper we suggest that investigations of the x-ray properties of interstellar grains may profitably be conducted in sight lines to variable sources. Particular emphasis is given in this context to cataclysmic variables and related objects

X-ray spectra and time variability of active galactic nuclei

International Nuclear Information System (INIS)

Mushotzky, R.F.

1984-02-01

The X-ray spectra of broad line active galactic nuclei (AGN) of all types (Seyfert I's, NELG's, broadline radio galaxies) are well fit by a power law in the .5 to 100 keV band of man energy slope alpha .68 + or - .15. There is, as yet, no strong evidence for time variability of this slope in a given object. The constraints that this places on simple models of the central energy source are discussed. BL Lac objects have quite different X-ray spectral properties and show pronounced X-ray spectral variability. On time scales longer than 12 hours most radio quiet AGN do not show strong, delta I/I .5, variability. The probability of variability of these AGN seems to be inversely related to their luminosity. However characteristics timescales for variability have not been measured for many objects. This general lack of variability may imply that most AGN are well below the Eddington limit. Radio bright AGN tend to be more variable than radio quiet AGN on long, tau approx 6 month, timescales

Association between central papilla recession and gingival and interdental smile line.

Science.gov (United States)

Kolte, Abhay P; Kolte, Rajashri A; Agrawal, Anshuka A; Shrirao, Tushar; Mankar, Kamal

2017-11-30

Interdental soft tissues play a critical role in pink esthetics. The presence and preservation of the interdental papillae in the esthetic zone is as crucial as the shape and contour of the anterior teeth in achieving an esthetically pleasing smile. The present study determines the association of central papilla recession with gingival and interdental smile line in periodontally healthy patients of different age groups. The present study included 200 patients equally divided into 21 to 40 years and 41 to 60 years age groups. The clinical and photographic evaluation of the central papilla, with midfacial gingiva, and its relationship with the vermilion border was performed. In total, 137 patients exhibited presence of central papilla, whilst 63 patients had central papilla recession with variable extent. The male patients predominantly had presence of central papilla in both the age groups, with 86% and 64%, compared with 74% and 50% in females, respectively. High gingival smile line was seen in the majority of the patients (62%), and this trend was similar to high interdental smile line (82% of the patients). Esthetics is affected in individuals having papilla recession along with high gingival smile line and interdental smile line as compared to individuals with low or cupid bow gingival smile line and interdental smile line.

Self-renewal and differentiation capabilities are variable between human embryonic stem cell lines I3, I6 and BG01V

Directory of Open Access Journals (Sweden)

Rao Mahendra S

2009-06-01

Full Text Available Abstract Background A unique and essential property of embryonic stem cells is the ability to self-renew and differentiate into multiple cell lineages. However, the possible differences in proliferation and differentiation capabilities among independently-derived human embryonic stem cells (hESCs are not well known because of insufficient characterization. To address this question, a side-by-side comparison of 1 the ability to maintain an undifferentiated state and to self-renew under standard conditions; 2 the ability to spontaneously differentiate into three primary embryonic germ lineages in differentiating embryoid bodies; and 3 the responses to directed neural differentiation was made between three NIH registered hES cell lines I3 (TE03, I6 (TE06 and BG01V. Lines I3 and I6 possess normal XX and a normal XY karyotype while BG01V is a variant cell line with an abnormal karyotype derived from the karyotypically normal cell line BG01. Results Using immunocytochemistry, flow cytometry, qRT-PCR and MPSS, we found that all three cell lines actively proliferated and expressed similar "stemness" markers including transcription factors POU5F1/Oct3/4 and NANOG, glycolipids SSEA4 and TRA-1-81, and alkaline phosphatase activity. All cell lines differentiated into three embryonic germ lineages in embryoid bodies and into neural cell lineages when cultured in neural differentiation medium. However, a profound variation in colony morphology, growth rate, BrdU incorporation, and relative abundance of gene expression in undifferentiated and differentiated states of the cell lines was observed. Undifferentiated I3 cells grew significantly slower but their differentiation potential was greater than I6 and BG01V. Under the same neural differentiation-promoting conditions, the ability of each cell line to differentiate into neural progenitors varied. Conclusion Our comparative analysis provides further evidence for similarities and differences between three h

The Line-drawing Problem in Disease Definition.

Science.gov (United States)

Rogers, Wendy A; Walker, Mary Jean

2017-08-01

Biological dysfunction is regarded, in many accounts, as necessary and perhaps sufficient for disease. But although disease is conceptualized as all-or-nothing, biological functions often differ by degree. A tension is created by attempting to use a continuous variable as the basis for a categorical definition, raising questions about how we are to pinpoint the boundary between health and disease. This is the line-drawing problem. In this paper, we show how the line-drawing problem arises within "dysfunction-requiring" accounts of disease, such as those of Christopher Boorse and Jerome Wakefield. We then provide several detailed examples to establish that biological dysfunction cannot provide a boundary. We examine potential ways of resolving the line-drawing problem, either by dropping one of the claims that generates it, or by appealing to additional criteria. We argue that two of these options are plausible, and that each of these can be applied with regard to different diseases. © The Author 2017. Published by Oxford University Press, on behalf of the Journal of Medicine and Philosophy Inc. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Rectifiability of Line Defects in Liquid Crystals with Variable Degree of Orientation

Science.gov (United States)

Alper, Onur

2018-04-01

In [2], H ardt, L in and the author proved that the defect set of minimizers of the modified Ericksen energy for nematic liquid crystals consists locally of a finite union of isolated points and Hölder continuous curves with finitely many crossings. In this article, we show that each Hölder continuous curve in the defect set is of finite length. Hence, locally, the defect set is rectifiable. For the most part, the proof closely follows the work of D e L ellis et al. (Rectifiability and upper minkowski bounds for singularities of harmonic q-valued maps, arXiv:1612.01813, 2016) on harmonic Q-valued maps. The blow-up analysis in A lper et al. (Calc Var Partial Differ Equ 56(5):128, 2017) allows us to simplify the covering arguments in [11] and locally estimate the length of line defects in a geometric fashion.

Search for relation between flares and photometric variability outside of flares in EV Lac

International Nuclear Information System (INIS)

Rojzman, G.Sh.

1984-01-01

The observations of the flare star EV Lac in July-September 1981 have confirmed the existence of photometric variability outside the flares during the night. It was found that, as a rule, a slow increase of brightness in U and B bands during 1-2 hours preceded the flares. It is suggested that the variability outside the flares is the result of the variability of chpomospheric emission lines and continuum that are emitted by the chromospheric preflare formations

Line facilities outline

International Nuclear Information System (INIS)

1998-08-01

This book deals with line facilities. The contents of this book are outline line of wire telecommunication ; development of line, classification of section of line and theory of transmission of line, cable line ; structure of line, line of cable in town, line out of town, domestic cable and other lines, Optical communication ; line of optical cable, transmission method, measurement of optical communication and cable of the sea bottom, Equipment of telecommunication line ; telecommunication line facilities and telecommunication of public works, construction of cable line and maintenance and Regulation of line equipment ; regulation on technique, construction and maintenance.

A temporally and spatially resolved electron density diagnostic method for the edge plasma based on Stark broadening

Energy Technology Data Exchange (ETDEWEB)

Zafar, A., E-mail: zafara@ornl.gov [Department of Nuclear Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States); Martin, E. H.; Isler, R. C.; Caughman, J. B. O. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States); Shannon, S. C. [Department of Nuclear Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

2016-11-15

An electron density diagnostic (≥10{sup 10} cm{sup −3}) capable of high temporal (ms) and spatial (mm) resolution is currently under development at Oak Ridge National Laboratory. The diagnostic is based on measuring the Stark broadened, Doppler-free spectral line profile of the n = 6–2 hydrogen Balmer series transition. The profile is then fit to a fully quantum mechanical model including the appropriate electric and magnetic field operators. The quasi-static approach used to calculate the Doppler-free spectral line profile is outlined here and the results from the model are presented for H-δ spectra for electron densities of 10{sup 10}–10{sup 13} cm{sup −3}. The profile shows complex behavior due to the interaction between the magnetic substates of the atom.

Genetic Variability for Drought Adaptive Traits in A-511 Maize ...

African Journals Online (AJOL)

Drought causes considerable yield reduction in maize (Zea mays L.) grown in the moisture stressed areas of Ethiopia. Increased crop production through improvement is expected if the adapted local genotypes possess variability for drought adaptive traits. Randomly taken 196 S1 lines generated from Population A-511 ...

Disk accretion onto magnetic T Tauri stars

International Nuclear Information System (INIS)

Koenigl, A.

1991-01-01

The dynamical and radiative consequences of disk accretion onto magnetic T Tauri stars (TTS) are examined using the Ghosh and Lamb model. It is shown that a prolonged disk accretion phase is compatible with the low rotation rates measured in these stars if they possess a kilogauss strength field that disrupts the disk at a distance of a few stellar radii from the center. It is estimated that a steady state in which the net torque exerted on the star is zero can be attained on a time scale that is shorter than the age of the youngest visible TTS. Although the disk does not develop an ordinary shear boundary layer in this case, one can account for the observed UV excess and Balmer emission in terms of the shocks that form at the bottom of the high-latitude magnetic accretion columns on the stellar surface. This picture also provides a natural explanation of some of the puzzling variability properties of stars like DF Tau and RY Lup. YY Ori stars are interpreted as magnetic TTS in which the observer's line of sight is roughly parallel to an accretion column. 37 refs

A NEW Hα EMISSION-LINE SURVEY IN THE ORION NEBULA CLUSTER

International Nuclear Information System (INIS)

Szegedi-Elek, E.; Kun, M.; Pál, A.; Balázs, L. G.; Reipurth, B.; Willman, M.

2013-01-01

We present results from an Hα emission line survey in a 1 deg 2 area centered on the Orion Nebula Cluster, obtained with the Wide Field Grism Spectrograph 2 on the 2.2 m telescope of the University of Hawaii. We identified 587 stars with Hα emission, 99 of which, located mainly in the outer regions of the observed area, have not appeared in previous Hα surveys. We determined the equivalent width (EW) of the line and, based on this, classified 372 stars as classical T Tauri stars (CTTSs) and 187 as weak-line T Tauri stars (WTTSs). Simultaneous r', i' photometry indicates a limiting magnitude of r' ∼ 20 mag, but the sample is incomplete at r' > 17 mag. The surface distribution of the Hα emission stars reveals a clustered population and a dispersed population, the former consisting of younger and more massive young stars than the latter. Comparison of the derived EWs with those found in the literature indicates variability of the Hα line. We found that the typical amplitudes of the variability are not greater than a factor of two to three in most cases. We identified a subgroup of low-EW stars with infrared signatures indicative of optically thick accretion disks. We studied the correlations between the EW and other properties of the stars. Based on literature data, we examined several properties of our CTTS and WTTS subsamples and found significant differences in mid-infrared color indices, average rotational periods, and spectral energy distribution characteristics of the subsamples

A NEW Hα EMISSION-LINE SURVEY IN THE ORION NEBULA CLUSTER

Energy Technology Data Exchange (ETDEWEB)

Szegedi-Elek, E.; Kun, M.; Pál, A.; Balázs, L. G. [Konkoly Observatory, H-1121 Budapest, Konkoly Thege út 15-17 (Hungary); Reipurth, B.; Willman, M., E-mail: eelza@konkoly.hu [Institute for Astronomy, University of Hawaii at Manoa, 640 N. Aohoku Place, Hilo, HI 96720 (United States)

2013-10-01

We present results from an Hα emission line survey in a 1 deg{sup 2} area centered on the Orion Nebula Cluster, obtained with the Wide Field Grism Spectrograph 2 on the 2.2 m telescope of the University of Hawaii. We identified 587 stars with Hα emission, 99 of which, located mainly in the outer regions of the observed area, have not appeared in previous Hα surveys. We determined the equivalent width (EW) of the line and, based on this, classified 372 stars as classical T Tauri stars (CTTSs) and 187 as weak-line T Tauri stars (WTTSs). Simultaneous r', i' photometry indicates a limiting magnitude of r' ∼ 20 mag, but the sample is incomplete at r' > 17 mag. The surface distribution of the Hα emission stars reveals a clustered population and a dispersed population, the former consisting of younger and more massive young stars than the latter. Comparison of the derived EWs with those found in the literature indicates variability of the Hα line. We found that the typical amplitudes of the variability are not greater than a factor of two to three in most cases. We identified a subgroup of low-EW stars with infrared signatures indicative of optically thick accretion disks. We studied the correlations between the EW and other properties of the stars. Based on literature data, we examined several properties of our CTTS and WTTS subsamples and found significant differences in mid-infrared color indices, average rotational periods, and spectral energy distribution characteristics of the subsamples.

IR finite one-loop box scalar integral with massless internal lines

International Nuclear Information System (INIS)

Duplancic, G.; Nizic, B.

2002-01-01

The IR finite one-loop box scalar integral with massless internal lines has been recalculated. The result is very compact, simple and valid for arbitrary values of the relevant kinematic variables. It is given in terms of only two dilogarithms and a few logarithms, all of very simple arguments. (orig.)

Spectral Variability of the Herbig Ae/Be Star HD 37806

Science.gov (United States)

Pogodin, M. A.; Pavlovskiy, S. E.; Kozlova, O. V.; Beskrovnaya, N. G.; Alekseev, I. Yu.; Valyavin, G. G.

2018-03-01

Results are reported from a spectroscopic study of the Herbig Ae/Be star HD 37806 from 2009 through 2017 using high resolution spectrographs at the Crimean Astrophysical Observatory and the OAN SPM Observatory in Mexico. 72 spectra of this object near the Hα, Hβ, HeI 5876 and D NaI lines are analyzed. The following results were obtained: 1. The type of spectral profile of the Hα line can change from P Cyg III to double emission and vice versa over a time scale on the order of a month. 2. Narrow absorption components are observed in the profiles of the Hα and D NaI lines with radial velocities that vary over a characteristic time on the order of a day. 3. On some days, the profiles of the Hβ, HeI 5876, and D NaI lines show signs of accretion of matter to the star with a characteristic lifetime of a few days. A possible interpretation of these phenomena was considered. The transformation of the Hα profile may be related to a change in the outer latitudinal width of the boundary of the wind zone. The narrow variable absorption lines may be caused by the rotation of local azimuthal inhomogeneities in the wind zone owing to the interaction of the disk with the star's magnetosphere in a propeller regime. Several current theoretical papers that predict the formation of similar inhomogeneous wind structures were examined. It is suggested that the episodes with signs of accretion in the spectral line profiles cannot be a consequence of the modulation of these profiles by the star's rotation but are more likely caused by sudden, brief changes in the accretion rate. These spectral observations of HD 37806 should be continued in a search for cyclical variability in the spectral parameters in order to identify direct signs of magnetospheric accretion and detect possible binary behavior in this object.

RRS Discovery Cruise 312, 11-31 Oct 2006. The extended Ellett Line 2006

OpenAIRE

Allen, J.T.

2007-01-01

UK oceanographers have been making repeated measurements on a short section across the Rockall Trough, since 1975. The section consists of a series of stations from the Scottish continental shelf to Rockall. The time series was established by David Ellett and was thus called the "Ellett Line". The Ellett line is one of a relatively small number of high quality physical time series in the North Atlantic Ocean and is important for monitoring oceanic climate variability.Since 1996 NOCS and SAMS ...

Similarity law for Widom lines and coexistence lines.

Science.gov (United States)

Banuti, D T; Raju, M; Ihme, M

2017-05-01

The coexistence line of a fluid separates liquid and gaseous states at subcritical pressures, ending at the critical point. Only recently, it became clear that the supercritical state space can likewise be divided into regions with liquidlike and gaslike properties, separated by an extension to the coexistence line. This crossover line is commonly referred to as the Widom line, and is characterized by large changes in density or enthalpy, manifesting as maxima in the thermodynamic response functions. Thus, a reliable representation of the coexistence line and the Widom line is important for sub- and supercritical applications that depend on an accurate prediction of fluid properties. While it is known for subcritical pressures that nondimensionalization with the respective species critical pressures p_{cr} and temperatures T_{cr} only collapses coexistence line data for simple fluids, this approach is used for Widom lines of all fluids. However, we show here that the Widom line does not adhere to the corresponding states principle, but instead to the extended corresponding states principle. We resolve this problem in two steps. First, we propose a Widom line functional based on the Clapeyron equation and derive an analytical, species specific expression for the only parameter from the Soave-Redlich-Kwong equation of state. This parameter is a function of the acentric factor ω and compares well with experimental data. Second, we introduce the scaled reduced pressure p_{r}^{*} to replace the previously used reduced pressure p_{r}=p/p_{cr}. We show that p_{r}^{*} is a function of the acentric factor only and can thus be readily determined from fluid property tables. It collapses both subcritical coexistence line and supercritical Widom line data over a wide range of species with acentric factors ranging from -0.38 (helium) to 0.34 (water), including alkanes up to n-hexane. By using p_{r}^{*}, the extended corresponding states principle can be applied within

The Task Manager for the LHCb On-Line Farm

CERN Document Server

Bonifazi, F; Carbone, A; Galli, D; Gregori, D; Marconi, U; Peco, G; Vagnoni, V

2004-01-01

The Task Manager is a utility to start, stop and list processes on the on-line farm. Each process started by the Task Manager has a string environment variable set, named UTGID (User defined unique Thread Group Identifier) which allows to identify the process. The Task Manager uses the UTGID to list the running processes and to identify the processes to be stopped. It has also the ability to start a process using a particular user name and to set the scheduler type and the priority for the process itself. The Task Manager package includes a Linux DIM server (tmSrv), four Linux command line DIM clients (tmStart, tmLs, tmKill and tmStop) and a JCOP (Joint Control Project) PVSS client.

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

Science.gov (United States)

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

2016-05-01

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

Grounding line transient response in marine ice sheet models

Directory of Open Access Journals (Sweden)

A. S. Drouet

2013-03-01

Full Text Available Marine ice-sheet stability is mostly controlled by the dynamics of the grounding line, i.e. the junction between the grounded ice sheet and the floating ice shelf. Grounding line migration has been investigated within the framework of MISMIP (Marine Ice Sheet Model Intercomparison Project, which mainly aimed at investigating steady state solutions. Here we focus on transient behaviour, executing short-term simulations (200 yr of a steady ice sheet perturbed by the release of the buttressing restraint exerted by the ice shelf on the grounded ice upstream. The transient grounding line behaviour of four different flowline ice-sheet models has been compared. The models differ in the physics implemented (full Stokes and shallow shelf approximation, the numerical approach, as well as the grounding line treatment. Their overall response to the loss of buttressing is found to be broadly consistent in terms of grounding line position, rate of surface elevation change and surface velocity. However, still small differences appear for these latter variables, and they can lead to large discrepancies (> 100% observed in terms of ice sheet contribution to sea level when cumulated over time. Despite the recent important improvements of marine ice-sheet models in their ability to compute steady state configurations, our results question the capacity of these models to compute short-term reliable sea-level rise projections.

Bio-inspired online variable recruitment control of fluidic artificial muscles

Science.gov (United States)

Jenkins, Tyler E.; Chapman, Edward M.; Bryant, Matthew

2016-12-01

This paper details the creation of a hybrid variable recruitment control scheme for fluidic artificial muscle (FAM) actuators with an emphasis on maximizing system efficiency and switching control performance. Variable recruitment is the process of altering a system’s active number of actuators, allowing operation in distinct force regimes. Previously, FAM variable recruitment was only quantified with offline, manual valve switching; this study addresses the creation and characterization of novel, on-line FAM switching control algorithms. The bio-inspired algorithms are implemented in conjunction with a PID and model-based controller, and applied to a simulated plant model. Variable recruitment transition effects and chatter rejection are explored via a sensitivity analysis, allowing a system designer to weigh tradeoffs in actuator modeling, algorithm choice, and necessary hardware. Variable recruitment is further developed through simulation of a robotic arm tracking a variety of spline position inputs, requiring several levels of actuator recruitment. Switching controller performance is quantified and compared with baseline systems lacking variable recruitment. The work extends current variable recruitment knowledge by creating novel online variable recruitment control schemes, and exploring how online actuator recruitment affects system efficiency and control performance. Key topics associated with implementing a variable recruitment scheme, including the effects of modeling inaccuracies, hardware considerations, and switching transition concerns are also addressed.

The Method of Lines for Ternary Diffusion Problems

Directory of Open Access Journals (Sweden)

Henryk Leszczyński

2014-01-01

Full Text Available The method of lines (MOL for diffusion equations with Neumann boundary conditions is considered. These equations are transformed by a discretization in space variables into systems of ordinary differential equations. The proposed ODEs satisfy the mass conservation law. The stability of solutions of these ODEs with respect to discrete L2 norms and discrete W1,∞ norms is investigated. Numerical examples confirm the parabolic behaviour of this model and very regular dynamics.

Long-term Variability of H2CO Masers in Star-forming Regions

Science.gov (United States)

Andreev, N.; Araya, E. D.; Hoffman, I. M.; Hofner, P.; Kurtz, S.; Linz, H.; Olmi, L.; Lorran-Costa, I.

2017-10-01

We present results of a multi-epoch monitoring program on variability of 6 cm formaldehyde (H2CO) masers in the massive star-forming region NGC 7538 IRS 1 from 2008 to 2015, conducted with the Green Bank Telescope, the Westerbork Radio Telescope , and the Very Large Array. We found that the similar variability behaviors of the two formaldehyde maser velocity components in NGC 7538 IRS 1 (which was pointed out by Araya and collaborators in 2007) have continued. The possibility that the variability is caused by changes in the maser amplification path in regions with similar morphology and kinematics is discussed. We also observed 12.2 GHz methanol and 22.2 GHz water masers toward NGC 7538 IRS 1. The brightest maser components of CH3OH and H2O species show a decrease in flux density as a function of time. The brightest H2CO maser component also shows a decrease in flux density and has a similar LSR velocity to the brightest H2O and 12.2 GHz CH3OH masers. The line parameters of radio recombination lines and the 20.17 and 20.97 GHz CH3OH transitions in NGC 7538 IRS 1 are also reported. In addition, we observed five other 6 cm formaldehyde maser regions. We found no evidence of significant variability of the 6 cm masers in these regions with respect to previous observations, the only possible exception being the maser in G29.96-0.02. All six sources were also observed in the {{{H}}}213{CO} isotopologue transition of the 6 cm H2CO line; {{{H}}}213{CO} absorption was detected in five of the sources. Estimated column density ratios [{{{H}}}212{CO}]/[{{{H}}}213{CO}] are reported.

Spatial variability in airborne pollen concentrations.

Science.gov (United States)

Raynor, G S; Ogden, E C; Hayes, J V

1975-03-01

Tests were conducted to determine the relationship between airborne pollen concentrations and distance. Simultaneous samples were taken in 171 tests with sets of eight rotoslide samplers spaced from one to 486 M. apart in straight lines. Use of all possible pairs gave 28 separation distances. Tests were conducted over a 2-year period in urban and rural locations distant from major pollen sources during both tree and ragweed pollen seasons. Samples were taken at a height of 1.5 M. during 5-to 20-minute periods. Tests were grouped by pollen type, location, year, and direction of the wind relative to the line. Data were analyzed to evaluate variability without regard to sampler spacing and variability as a function of separation distance. The mean, standard deviation, coefficient of variation, ratio of maximum to the mean, and ratio of minimum to the mean were calculated for each test, each group of tests, and all cases. The average coefficient of variation is 0.21, the maximum over the mean, 1.39 and the minimum over the mean, 0.69. No relationship was found with experimental conditions. Samples taken at the minimum separation distance had a mean difference of 18 per cent. Differences between pairs of samples increased with distance in 10 of 13 groups. These results suggest that airborne pollens are not always well mixed in the lower atmosphere and that a sample becomes less representative with increasing distance from the sampling location.

Photometric Variability of the Be Star Population

International Nuclear Information System (INIS)

Labadie-Bartz, Jonathan; Pepper, Joshua; McSwain, M. Virginia; Bjorkman, J. E.; Bjorkman, K. S.; Lund, Michael B.; Rodriguez, Joseph E.; Stassun, Keivan G.; Stevens, Daniel J.; James, David J.; Kuhn, Rudolf B.; Siverd, Robert J.; Beatty, Thomas G.

2017-01-01

Be stars have generally been characterized by the emission lines in their spectra, and especially the time variability of those spectroscopic features. They are known to also exhibit photometric variability at multiple timescales, but have not been broadly compared and analyzed by that behavior. We have taken advantage of the advent of wide-field, long-baseline, and high-cadence photometric surveys that search for transiting exoplanets to perform a comprehensive analysis of brightness variations among a large number of known Be stars. The photometric data comes from the KELT transit survey, with a typical cadence of 30 minutes, a baseline of up to 10 years, photometric precision of about 1%, and coverage of about 60% of the sky. We analyze KELT light curves of 610 known Be stars in both the northern and southern hemispheres in an effort to study their variability. Consistent with other studies of Be star variability, we find most of the stars to be photometrically variable. We derive lower limits on the fraction of stars in our sample that exhibit features consistent with non-radial pulsations (25%), outbursts (36%), and long-term trends in the circumstellar disk (37%), and show how these are correlated with spectral sub-types. Other types of variability, such as those owing to binarity, are also explored. Simultaneous spectroscopy for some of these systems from the Be Star Spectra database allow us to better understand the physical causes for the observed variability, especially in cases of outbursts and changes in the disk.