WorldWideScience
 
 
1

K- and M-type dwarf stars within 25 parsecs of the sun. I. The age-chromospheric activity relations from H-alpha equivalent widths  

International Nuclear Information System (INIS)

The available equivalent-width measurements of H-alpha in dwarf K and M stars within 25 pc of the sun indicate that, as a chromospheric diagnostic, the H-alpha decay rate is about t exp 0.5. The decay rate of line emission in Mg II h and k (Ca II H and K) is about t exp 0.3. The decay rates are derived from observations of members of a few stellar superclusters and groups, for which the consistency of results argues strongly for the importance of more data. The only major inconsistency encountered is for the unique HR 1614 group which, in the age/chromospheric-activity progression, gives different results from Mg II h and k and from WH-alpha. 63 refs

1990-01-01

2

ARES: Automatic Routine for line Equivalent widths in stellar Spectra  

Science.gov (United States)

ARES was developed for the measurement of Equivalent Width of absortion lines in stellar spectra; it can also be used to determine fundamental spectroscopic stellar parameters.The code reads a 1D FITS spectra and fits the requested lines in order to calculate the Equivalent width. The code is written in C++ based on the standard method of determining EWs. It automates the manual procedure that one normally carries out when using interactive routines such as the splot routine implemented in IRAF.

Sousa, Sérgio G.

2012-05-01

3

pacce: Perl algorithm to compute continuum and equivalent widths  

Science.gov (United States)

We present Perl Algorithm to Compute continuum and Equivalent Widths ( pacce). We describe the methods used in the computations and the requirements for its usage. We compare the measurements made with pacce and "manual" ones made using iraf splot task. These tests show that for synthetic simple stellar population (SSP) models the equivalent widths strengths are very similar (differences ?0.2 Å) for both measurements. In real stellar spectra, the correlation between both values is still very good, but with differences of up to 0.5 Å. pacce is also able to determine mean continuum and continuum at line center values, which are helpful in stellar population studies. In addition, it is also able to compute the uncertainties in the equivalent widths using photon statistics. The code is made available for the community through the web at http://www.if.ufrgs.br/~riffel/software.html .

Riffel, Rogério; Borges Vale, Tibério

2011-08-01

4

PACCE: Perl Algorithm to Compute Continuum and Equivalent Widths  

CERN Multimedia

We present Perl Algorithm to Compute continuum and Equivalent Widths (pacce). We describe the methods used in the computations and the requirements for its usage. We compare the measurements made with pacce and "manual" ones made using iraf splot task. These tests show that for SSP models the equivalent widths strengths are very similar (differences <0.2A) for both measurements. In real stellar spectra, the correlation between both values is still very good, but with differences of up to 0.5A. pacce is also able to determine mean continuum and continuum at line center values, which are helpful in stellar population studies. In addition, it is also able to compute the uncertainties in the equivalent widths using photon statistics. The code is made available for the community through the web at http://www.if.ufrgs.br/~riffel/software.html.

Riffel, Rogério

2011-01-01

5

FUNDPAR: A Program for deriving Fundamental Parameters from Equivalent Widths  

CERN Document Server

We implemented a fortran code that determine fundamental parameters of solar type stars from a list of Fe line equivalent widths. The solution should verify 3 conditions in the standard method: ionization equilibrium, excitation equilibrium and independence between metallicity and equivalent widths. We added the condition that the input metallicity of the model atmosphere should be similar to the output metallicity derived with equivalent widths. Solar-scaled Kurucz model atmospheres with NEWODF opacities are calculated with an independent program. Parameter files control different details, such as the mixing-length parameter, the overshooting, the damping of the lines and the weight factors in the definition of the chi2 function. FUNDPAR derive the uncertainties following 2 methods: the criteria of Gonzalez & Vanture (1998) and the dispersion using the chi2 function. The code use the 2009 version of the MOOG program. The results derived with FUNDPAR are in agreement with previous determinations in the li...

Saffe, Carlos

2010-01-01

6

Tool for Automatic Measurement of Equivalent width (TAME)  

Science.gov (United States)

We present a tool for measuring the equivalent width (EW) in high-resolution spectra. The Tool for Automatic Measurement of Equivalent width (TAME) provides the EWs of spectral lines by profile fitting in an automatic or interactive mode, which can yield a more precise result through the adjustment of the local continuum and fitting parameters. The automatic EW results of TAME have been verified by comparing them with the manual EW measurements by the IRAF splot task using the high-resolution spectrum of the Sun and measuring EWs in the synthetic spectra with different spectral resolutions and signal-to-noise (S/N) ratios. The EWs measured by TAME agree well with the manually measured values, with a dispersion of less than 2 mÅ. By comparing the input EWs for synthetic spectra and EWs measured by TAME, we conclude that it is reliable for measuring the EWs in a spectrum with a spectral resolution of R ? 20 000 and find that the errors in EWs are less than 1 mÅ for an S/N ratio ?100.

Kang, Wonseok; Lee, Sang-Gak

2012-10-01

7

A New Code for Automatic Determination of Equivalent Widths: Automatic Routine for Line Equivalent Widths in Stellar Spectra (ARES)  

Science.gov (United States)

We present a new automatic code (ARES) for the determination of equivalent widths of absorption lines present in stellar spectra. We also describe its use for the determination of fundamental spectroscopic stellar parameters. The code is written in C++ based on the standard method of determining EWs, and is available for the community. The code automates the manual procedure that the users normally carry out when using interactive routines such as the splot routine implemented in IRAF. We test the code using both simulated and real spectra with different levels of resolution and noise comparing its measurements to the manual ones obtained in the standard way. The results shows a small systematic difference, always bellow 1.5mA. This can be explained by errors in the manual measurements due to subjective continuum determination. The code works better and faster than others tested before. This code will be used to analyze spectra from the HARPS sample to search extrasolar planets.

Sousa, Sergio A. Gonçalves; Santos, Nuno Cardoso; Monteiro, M. J. P. F. G.; Israelian, Garik; Mayor, Michel

2007-08-01

8

A new code for automatic determination of equivalent widths: Automatic Routine for line Equivalent widths in stellar Spectra (ARES)  

CERN Document Server

We present a new automatic code (ARES) for determining equivalent widths of the absorption lines present in stellar spectra. We also describe its use for determining fundamental spectroscopic stellar parameters. The code is written in C++ based on the standard method of determining EWs and is available for the community. The code automates the manual procedure that the users normally carry out when using interactive routines such as the splot routine implemented in IRAF. We test the code using both simulated and real spectra with different levels of resolution and noise and comparing its measurements to the manual ones obtained in the standard way. The results shows a small systematic difference, always below 1.5m\\AA. This can be explained by errors in the manual measurements caused by subjective continuum determination. The code works better and faster than others tested before.

Sousa, S G; Israelian, G; Mayor, M; Monteiro, M J P F G

2007-01-01

9

FUNDPAR: A program for Deriving Fundamental Parameters from Equivalent Widths  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish Implementamos un programa en Fortran que determina parámetros fundamentales de estrellas de tipo solar, a partir de anchos equivalentes del Fe. La solución debe verificar tres condiciones en el método estándar: equilibrio de ionización, equilibrio de excitación e independencia entre abundancias y an [...] chos equivalentes. Calculamos modelos de atmósfera de Kurucz con opacidades NEWODF. Detalles como el parámetro de longitud de mezcla, el sobre impulso convectivo, etc. se calculan con un programa independiente. FUNDPAR calcula las incertezas por dos métodos: el criterio de Gonzalez & Vanture (1998) y utilizando la función ?² . Los resultados derivados con FUNDPAR están de acuerdo con determinaciones previas en la literatura. En particular obtuvimos parámetros fundamentales de 58 estrellas con exoplanetas. El programa está disponible en la red1. Abstract in english We implemented a Fortran code that determines fundamental parameters of solar type stars from a list of Fe line equivalent widths. The solution should verify three conditions in the standard method: ionization equilibrium, excitation equilibrium and independence between metallicity and equivalent wi [...] dths. Solarscaled Kurucz model atmospheres with NEWODF opacities are calculated with an independent program. Parameter files control different details, such as the mixinglength parameter and the overshooting. FUNDPAR derives the uncertainties following two methods: the criterion of Gonzalez & Vanture (1998) and the dispersion using the ?2 function. The code uses the 2009 version of the MOOG program. The results derived with FUNDPAR are in agreement with previous determinations in the literature. The program is freely available from the web1.

Saffe, C.

10

Equivalent widths of 5 giants in 47 Tuc (Alves-Brito+, 2005)  

Science.gov (United States)

Equivalent widths (EW) measured for Fe I and Fe II lines using IRAF task SPLOT and DAOSPEC. Column one gives the wavelength, column two the atomic species. Columns three and four give the excitation potential (EP) and gf-values, respectively. Columns 5-9 give the measured equivalent widths for the five stars of the sample using IRAF, while Columns 10-14 give the equivalent widths obtained using DAOSPEC. (2 data files).

Alves-Brito, A.; Barbuy, B.; Ortolani, S.; Momany, I.; Hill, V.; Zoccali, M.; Renzini, A.; Minniti, D.; Pasquini, L.; Bica, E.; Rich, R. M.

2005-02-01

11

Rapid H-alpha variability in T Coronae Borealis  

CERN Document Server

We report our search for variability in the H-alpha emission line of the recurrent novae T CrB with time resolution 10-15 minutes. This is comparable with the time scale of the photometric flickering observed in this object. This is the first time that observations of the short time scale variation in emission lines have been made in this object. On two nights (990106 and 990107) we detected statistically significant variability (at 0.99 confidence level) in the line profile of H-alpha. This variability is confined in the central part of the emission line (\\pm 100 km/s) although FWZI(H-alpha) is ~800 km/s. The variability in the line profile is accompanied with variability of the total equivalent width, EW(H-alpha), \\pm 8% for 990106, and \\pm 6% for 990107 (calculated from the mean value of EW). Assuming Keplerian motion, the variability is generated at a distance ~20-30 R_Solar from the white dwarf, which is approximately the radius of the ring the stream of gas forms as it flows away from L_1. On three othe...

Zamanov, R; Bode, M F; Porter, J M; Tomov, N A

2004-01-01

12

Non-LTE equivalent widths for Si II, III and IV  

Energy Technology Data Exchange (ETDEWEB)

Equivalent widths for a set of Si II, III and IV lines reliable for the determination of temperatures in the B star parameter range are given. They are calculated on a fine grid of LTE line blanketed model atmospheres and lie in the wavelength region from 4070 A to 5070 A.

Becker, S.R.; Butler, K. (Muenchen Univ. (DE). Inst. fuer Astronomie und Astrophysik)

1990-07-01

13

H Alpha Mottles.  

Science.gov (United States)

Mottles located in the dark lanes that form the H alpha chromospheric network are longer lived than those that lie within network cells. The two groups of mottles are similar in size and shape. Bright mottles are found to be slightly larger than dark ones...

C. Sawyer

1971-01-01

14

Galactic interstellar abundance surveys with IUE. II - The equivalent widths and column densities  

Science.gov (United States)

This paper continues a survey of interstellar densities, abundances, and cloud structure in the Galaxy, using the International Ultraviolet Explorer (IUE) satellite. Equivalent widths of 18 ultraviolet resonance transitions are presented and column densities for Si II, Mn II, Fe II, S II, and Zn II toward 261 early-type stars are derived. These equivalent widths and column densities agree within the stated errors of earlier Copernicus, BUSS, or IUE surveys of Mn II, Fe II, S II, and Zn II for 45 stars in common. The column densities are derived from single-component curves of growth with a common b-value based on that of Fe II and Si II.

Van Steenberg, Michael E.; Shull, J. Michael

1988-01-01

15

The reddening law of Type Ia Supernovae: separating intrinsic variability from dust using equivalent widths  

CERN Document Server

We employ 76 type Ia supernovae with optical spectrophotometry within 2.5 days of B-band maximum light obtained by the Nearby Supernova Factory to derive the impact of Si and Ca features on supernovae intrinsic luminosity and determine a dust reddening law. We use the equivalent width of Si II {\\lambda}4131 in place of light curve stretch to account for first-order intrinsic luminosity variability. The resultant empirical spectral reddening law exhibits strong features associated with Ca II and Si II {\\lambda}6355. After applying a correction based on the Ca II H&K equivalent width we find a reddening law consistent with a Cardelli extinction law. Using the same input data, we compare this result to synthetic rest-frame UBVRI-like photometry in order to mimic literature observations. After corrections for signatures correlated with Si II {\\lambda}4131 and Ca II H&K equivalent widths, and introducing an empirical correlation between colors, we determine the dust component in each band. We find a value ...

Chotard, N; Aldering, G; Antilogus, P; Aragon, C; Bailey, S; Baltay, C; Bongard, S; Buton, C; Canto, A; Childress, M; Copin, Y; Fakhouri, H K; Hsiao, E Y; Kerschhaggl, M; Kowalski, M; Loken, S; Nugent, P; Paech, K; Pain, R; Pecontal, E; Pereira, R; Perlmutter, S; Rabinowitz, D; Runge, K; Scalzo, R; Smadja, G; Tao, C; Thomas, R C; Weaver, B A; Wu, C

2011-01-01

16

Equivalent widths of Li, Na, Fe, Ca in NGC 6397 (Lind+, 2009)  

Science.gov (United States)

The tables contain coordinates, photometry, derived stellar parameters, equivalent widths, and abundances for a large number of dwarfs, subgiant branch stars, and red giant branch stars in the metal-poor globular cluster NGC6397. All abundances are given in logarithmic units relative to hydrogen, according to A(x)=log(N(x)/N(H))+12, where N(x) is the number density of element x and N(H) the number density of hydrogen. Table 3 contains only a subset (32) of all targets. The oscillator strengths adopted are listed in the paper. (3 data files).

Lind, K.; Primas, F.; Charbonnel, C.; Grundahl, F.; Asplund, M.

2009-09-01

17

Resolving Stellar Atmospheres I: The H alpha line and comparisons to microlensing observations  

CERN Multimedia

We present work on H alpha spectral line characteristics in PHOENIX stellar model atmospheres and their comparison to microlensing observations. We examine in detail the H alpha equivalent width (EW) and the line shape characteristics for effective temperatures of 4500K< Teff < 5600K where H alpha is a strong spectral feature. We find that H alpha EW in models calculated under the assumption of local thermodynamic equilibrium (LTE) is up to 15% smaller than in models without this assumption, non-LTE models (NLTE) and that line shapes vary significantly for the two model types. A comparison with available high quality microlensing data, capable of tracing H alpha absorption across the face of one G5III giant, shows that the LTE model that fits the EW best is about 100K hotter than and the best-fitting NLTE model has a similar Teff as predicted by the spectral type analysis of the observed star but agree within the uncertainties of the observationally derived temperature. Neither LTE nor NLTE models fit t...

Thurl, C; Hauschildt, P H; Thurl, Christine; Sackett, Penny D.; Hauschildt, Peter H.

2006-01-01

18

H-alpha observations of the gamma-ray-emitting Be/X-ray binary LSI+61303: orbital modulation, disk truncation, and long-term variability  

CERN Document Server

We report 138 spectral observations of the H-alpha emission line of the radio- and gamma-ray-emitting Be/X-ray binary LSI+61303 obtained during the period of September 1998 -- January 2013. From measuring various H-alpha parameters, we found that the orbital modulation of the H-alpha is best visible in the equivalent width ratio EW(B)/EW(R), the equivalent width of the blue hump, and in the radial velocity of the central dip. The periodogram analysis confirmed that the H-alpha emission is modulated with the orbital and superorbital periods. For the past 20 years the radius of the circumstellar disk is similar to the Roche lobe size at the periastron. It is probably truncated by a 6:1 resonance. The orbital maximum of the equivalent width of H-alpha emission peaks after the periastron and coincides on average with the X-ray and gamma-ray maxima. All the spectra are available upon request from the authors and through the CDS.

Zamanov, R; Marti, J; Tomov, N A; Belcheva, G; Luque-Escamilla, P L; Latev, G

2013-01-01

19

Connection between orbital modulation of H-alpha and gamma-rays in the Be/X-ray binary LSI+61303  

CERN Document Server

We studied the average orbital modulation of various parameters (gamma-ray flux, H-alpha emission line, optical V band brightness) of the radio- and gamma-ray emitting Be/X-ray binary LSI+61303. Using the Spearman rank correlation test, we found highly significant correlations between the orbital variability of the equivalent width of the blue hump of the H-alpha and Fermi-LAT flux with a Spearman p-value 2e-5, and the equivalent widths ratio EW_B/EW_R and Fermi-LAT flux with p-value 9e-5. We also found a significant anti-correlation between Fermi-LAT flux and V band magnitude with p-value 7.10^{-4}. All these correlations refer to the average orbital variability, and we conclude that the H-alpha and gamma-ray emission processes in LSI+61303 are connected. The possible physical scenario is briefly discussed.

Zamanov, R; Stoyanov, K; Borissova, A; Tomov, N A

2013-01-01

20

Lyman Alpha Emitters in Hierarchical Galaxy Formation II. UV Continuum Luminosity Function and Equivalent Width Distribution  

CERN Multimedia

We present theoretical predictions of UV continuum luminosity function (UV LF) and Lya equivalent width (EW) distribution of Lyman alpha emitters (LAEs) in the framework of the hierarchical clustering model of galaxy formation. The model parameters about LAEs were determined by fitting to the observed Lya LF at z=5.7 in our previous study, and the fit indicates that extinction of Lya photons by dust is significantly less effective than that of UV continuum photons, implying clumpy dust distribution in interstellar medium. We then compare the predictions about UV LFs and EW distributions with a variety of observations at z~3-6, allowing no more free parameters and paying careful attention to the selection conditions of LAEs in each survey. We find that the predicted UV LFs and EW distributions are in nice agreement with observed data, and especially, our model naturally reproduces the existence of large EW LAEs(> 240 A) without introducing Pop III stars or top-heavy initial mass function. We show that both the...

Kobayashi, Masakazu A R; Nagashima, Masahiro

2009-01-01

 
 
 
 
21

Probing supernovae ejecta by $H\\alpha$ damping wings  

CERN Multimedia

It is predicted that H$\\alpha$ emission line at the early nebular epoch of type II-P supernovae may display robust observational effects of damping wings. This is illustrated by Monte-Carlo simulations. The strength of damping wing effects may be used to constrain parameters of the line-emitting zone. An anomalous redshift, width and red wing of H$\\alpha$ revealed by SN 1997D on day 150 are explained in terms of damping wing effects.

Chugai, N N

1999-01-01

22

H-alpha Imaging of Early-type (Sa-Sab) Spiral Galaxies II. Global Properties  

CERN Multimedia

New results, based on one of the most comprehensive H-alpha imaging surveys of nearby Sa-Sab spirals completed to date, reveals early-type spirals to be a diverse group of galaxies that span a wide range in massive star formation rates. While the majority of Sa-Sab galaxies in our sample are forming stars at a modest rate, a significant fraction (~29%) exhibit star formation rates greater than 1 M(solar/yr), rivaling the most prolifically star forming late-type spirals. A similar diversity is apparent in the star formation history of Sa-Sab spirals as measured by their H-alpha equivalent widths. Consistent with our preliminary results presented in the first paper in this series, we find giant HII regions (L(H-alpha)>10^{39}erg/s) in the disks of 37% of early-type spirals. We suspect that recent minor mergers or past interactions are responsible for the elevated levels of H-alpha emission and perhaps, for the presence of giant HII regions in these galaxies.

Hameed, S; Hameed, Salman; Devereux, Nick

2005-01-01

23

H{\\alpha} spectral monitoring of epsilon Aurig\\ae\\ 2009-2011 eclipse  

CERN Multimedia

We present and analyze epsilon Aurig\\ae\\ data concerning the evolution of the H{\\alpha} line on the occasion of the 2009 International observation campaign launched to cover the eclipse of this object. We visually inspect the dynamical spectrum constructed from the data and analyze the evolution with time of the EW (Equivalent Width) and of the radial velocity. The spectroscopic data reveal many details which confirm the complexity of the Aurig\\ae\\ system. The object is far from being understood. In particular, according to our measurements, the eclipse duration has been underestimated. A complete analysis of details revealed by our data would require much time and effort. Observers are encouraged to continue monitoring the H{\\alpha} line out of eclipse in the hope that it will provide further important information.

Mauclaire, B; Garrel, T; Leadbeater, R; Lopez, A

2012-01-01

24

Deneb: Time Series Analysis of H alpha, Radial Velocities, and Photometry  

Science.gov (United States)

The prototype A-type supergiant is Deneb (A2Iae). Lucy's (1976, ApJ 206, 499) harmonic analysis of radial velocities revealed 16 different pulsation modes and a binary period (approximately 850 days). Kaufer et al. (1996, A&A 305, 887) found evanescent periodicity in BA type supergiants. We analyzed 339 red-yellow echelle spectra (R=26,000) from Ritter Observatory, as well as 370 differential Stromgren photometric observations from the Four College Automated Photoelectric Telescope, all obtained during the years 1997-2001. Long-term variability studies such as the present one may elucidate physical processes in supergiant stars. H alpha shows a P Cygni morphology, with a variable emission component and a blue-shifted absorption component. We measured the net equivalent width of H alpha as well as that of its emission component. We used the radial velocities of the red Si II lines for analysis of photospheric variations. In each data set, we searched for periodicities with the CLEAN algorithm (Roberts et al. 1987, AJ 93, 968), both by observing season and globally. Noteworthy among our results is that some periods were found to persist, while others were present in only one observing season. Furthermore, the predominant period of the net H alpha equivalent width varied with each observing season. The binary period proposed by Lucy is not found in our data set. Research at Ritter Observatory is supported by The University of Toledo, the Fund for Astrophysical Research, and the American Astronomical Society Small Grants Program (NASA funds). Community access to the facility is supported by NSF-PREST. E.E. Allgaier's participation was supported by the NSF-REU program. S.J. Adelman's participation in this work was supported by NSF grant AST-0507381.

Richardson, N. D.; Morrison, N. D.; Adelman, S. J.; Allgaier, E. E.

2005-12-01

25

Equivalent width of copper and potassium resonance lines at 3247.54, 7665 Angst for Voigt profile by atomic absorption measurements  

Energy Technology Data Exchange (ETDEWEB)

A simple reliable theoretical approach is developed to calculate the equivalent width of copper and potassium resonance lines at 3247.54 and 7665 Angst using atomic absorption techniques. The calculations have been carried out for the two limiting cases of a pure Doppler (Gaussian) and Lorentzian (dispersion) line profiles. The more general case of a Voigt line profile leads to an efficient analytical formula permits a rapid estimate of the equivalent width with sufficient precision. The reliability of the approach has been verified by providing the curves of growth for the given spectral lines to describe the behavior of the equivalent width as the number of absorbing atoms in the ground state is increased. Allowance is made in the analysis for the dependence of the equivalent width for Voigt profile on the damping constant {alpha}, which is a measure of the half width of Lorentz profile relative to the Doppler profile.

Habib, A.A.M. E-mail: azhabib@yahoo.com

2004-03-15

26

Equivalent width of copper and potassium resonance lines at 3247.54, 7665 Angst for Voigt profile by atomic absorption measurements  

International Nuclear Information System (INIS)

A simple reliable theoretical approach is developed to calculate the equivalent width of copper and potassium resonance lines at 3247.54 and 7665 Angst using atomic absorption techniques. The calculations have been carried out for the two limiting cases of a pure Doppler (Gaussian) and Lorentzian (dispersion) line profiles. The more general case of a Voigt line profile leads to an efficient analytical formula permits a rapid estimate of the equivalent width with sufficient precision. The reliability of the approach has been verified by providing the curves of growth for the given spectral lines to describe the behavior of the equivalent width as the number of absorbing atoms in the ground state is increased. Allowance is made in the analysis for the dependence of the equivalent width for Voigt profile on the damping constant ?, which is a measure of the half width of Lorentz profile relative to the Doppler profile

2004-03-15

27

ON THE (NON-)ENHANCEMENT OF THE Ly{alpha} EQUIVALENT WIDTH BY A MULTIPHASE INTERSTELLAR MEDIUM  

Energy Technology Data Exchange (ETDEWEB)

It has been suggested that radiative transfer effects may explain the unusually high equivalent widths (EWs) of the Ly{alpha} line, observed occasionally from starburst galaxies, especially at high redshifts. If the dust is locked up inside high-density clouds dispersed in an empty intercloud medium, the Ly{alpha} photons could scatter off of the surfaces of the clouds, effectively having their journey confined to the dustless medium. The continuum radiation, on the other hand, does not scatter, and would thus be subject to absorption inside the clouds. This scenario is routinely invoked when Ly{alpha} EWs higher than what is expected theoretically are observed, although the ideal conditions under which the results are derived usually are not considered. Here we systematically examine the relevant physical parameters in this idealized framework, testing whether any astrophysically realistic scenarios may lead to such an effect. It is found that although clumpiness indeed facilitates the escape of Ly{alpha}, it is highly unlikely that any real interstellar media should result in a preferential escape of Ly{alpha} over continuum radiation. Other possible causes are discussed, and it is concluded that the observed high EWs are more likely to be caused by cooling radiation from cold accretion and/or anisotropic escape of the Ly{alpha} radiation.

Laursen, Peter; Duval, Florent; Oestlin, Goeran, E-mail: pela@dark-cosmology.dk [The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, SE-10691 Stockholm (Sweden)

2013-04-01

28

SPATIALLY RESOLVED H{alpha} MAPS AND SIZES OF 57 STRONGLY STAR-FORMING GALAXIES AT z {approx} 1 FROM 3D-HST: EVIDENCE FOR RAPID INSIDE-OUT ASSEMBLY OF DISK GALAXIES  

Energy Technology Data Exchange (ETDEWEB)

We investigate the buildup of galaxies at z {approx} 1 using maps of H{alpha} and stellar continuum emission for a sample of 57 galaxies with rest-frame H{alpha} equivalent widths >100 A in the 3D-HST grism survey. We find that the H{alpha} emission broadly follows the rest-frame R-band light but that it is typically somewhat more extended and clumpy. We quantify the spatial distribution with the half-light radius. The median H{alpha} effective radius r{sub e} (H{alpha}) is 4.2 {+-} 0.1 kpc but the sizes span a large range, from compact objects with r{sub e} (H{alpha}) {approx} 1.0 kpc to extended disks with r{sub e} (H{alpha}) {approx} 15 kpc. Comparing H{alpha} sizes to continuum sizes, we find H{alpha})/r{sub e} (R) > =1.3 {+-} 0.1 for the full sample. That is, star formation, as traced by H{alpha}, typically occurs out to larger radii than the rest-frame R-band stellar continuum; galaxies are growing their radii and building up from the inside out. This effect appears to be somewhat more pronounced for the largest galaxies. Using the measured H{alpha} sizes, we derive star formation rate surface densities, {Sigma}{sub SFR}. We find that {Sigma}{sub SFR} ranges from {approx}0.05 M{sub Sun} yr{sup -1} kpc{sup -2} for the largest galaxies to {approx}5 M{sub Sun} yr{sup -1} kpc{sup -2} for the smallest galaxies, implying a large range in physical conditions in rapidly star-forming z {approx} 1 galaxies. Finally, we infer that all galaxies in the sample have very high gas mass fractions and stellar mass doubling times <500 Myr. Although other explanations are also possible, a straightforward interpretation is that we are simultaneously witnessing the rapid formation of compact bulges and large disks at z {approx} 1.

Nelson, Erica June; Van Dokkum, Pieter G.; Skelton, Rosalind E.; Bezanson, Rachel; Lundgren, Britt [Astronomy Department, Yale University, New Haven, CT 06511 (United States); Brammer, Gabriel [European Southern Observatory, Alonson de Cordova 3107, Casilla 19001, Vitacura, Santiago (Chile); Foerster Schreiber, Natascha [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Franx, Marijn; Fumagalli, Mattia; Patel, Shannon; Labbe, Ivo [Leiden Observatory, Leiden University, Leiden (Netherlands); Rix, Hans-Walter; Da Cunha, Elisabete; Schmidt, Kasper B. [Max Planck Institute for Astronomy (MPIA), Koenigstuhl 17, 69117 Heidelberg (Germany); Kriek, Mariska [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Quadri, Ryan [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)

2012-03-10

29

DEFPOS H${\\alpha}$ Observations of W80 Complex  

CERN Document Server

We present H${\\alpha}$ emission line measurements of the W80 nebular complex. A total of 26 regions have been observed inside the nebula with the Dual Etalon Fabry-Perot Optical Spectrometer (DEFPOS) system at the f/48 Coude focus of 150 cm RTT150 telescope located at TUBITAK National Observatory (TUG) in Antalya/Turkey. The intensities, the local standard of rest (LSR) velocities ($V_{LSR}$), heliocentric radial velocities ($V_{HEL}$) and the linewidths at Full Width at Half Maximum (FWHM) of the H${\\alpha}$ emission lines have been determined from these observations. They lie in the range of 259 to 1159 Rayleigh {1R = 10$^{6}/4\\pi$ photons cm$^{-2}$ sr$^{-1}$ s$^{-1}$ = 2.4110$^{-7}$ erg cm$^{-2}$ sr$^{-1}$ s$^{-1}$ at H${\\alpha}$.} (R), 4 to 12 km s$^{-1}$ and 44 to 55 km s$^{-1}$, respectively. The radial velocity measurements show that there are several maxima and minima inside the W80. The new results confirm the literature that complex seems to be rather a uniform in radial velocity and no seen turbule...

Aksaker, Naz\\im

2012-01-01

30

Broad H$\\alpha$ Wing Formation in the Planetary Nebula IC 4997  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The young and compact planetary nebula IC 4997 is known to exhibit very broad wings with a width exceeding $5000 {\\rm km s^{-1}}$ around H$\\alpha$. We propose that the broad wings are formed through Rayleigh-Raman scattering involving atomic hydrogen, by which Ly$\\beta$ photons with a velocity width of a few $10^2 {\\rm km s^{-1}}$ are converted to optical photons and fill the H$\\alpha$ broad wing region. The conversion efficiency reaches 0.6 near the line center where the sc...

Lee, Hee-won; Hyung, Siek

1999-01-01

31

H$\\alpha$ Star Formation Rates of $z$ > 1 Galaxy Clusters in the IRAC Shallow Cluster Survey  

CERN Document Server

We present Hubble Space Telescope near-IR spectroscopy for 18 galaxy clusters at 1.0 < $z$ < 1.5 in the IRAC Shallow Cluster Survey. We use Wide Field Camera 3 grism data to spectroscopically identify H$\\alpha$ emitters in both the cores of galaxy clusters as well as in field galaxies. We find a large cluster-to-cluster scatter in the star formation rates within a projected radius of 500 kpc, and many of our clusters (~60%) have significant levels of star formation within a projected radius of 200 kpc. A stacking analysis reveals that dust reddening in these star-forming galaxies is positively correlated with stellar mass and may be higher in the field than the cluster at a fixed stellar mass. This may indicate a lower amount of gas in star-forming cluster galaxies than in the field population. Also, H$\\alpha$ equivalent widths of star-forming galaxies in the cluster environment are still suppressed below the level of the field. This suppression is most significant for lower mass galaxies (log M$_{*}$ &...

Zeimann, Gregory; Brodwin, Mark; Gonzalez, Anthony H; Mancone, Conor; Snyder, Gregory F; Stern, Daniel; Eisenhardt, Peter; Dey, Arjun; Moustakas, John

2013-01-01

32

Cloud modeling of a network region in H\\alpha  

Science.gov (United States)

In this paper, we analyze the physical properties of dark mottles in the chromospheric network using two-dimensional spectroscopic observations in H\\alpha obtained with the Göttingen Fabry-Perot Spectrometer in the Vacuum Tower Telescope at the Observatory del Teide, Tenerife. Cloud modeling was applied to measure the mottles' optical thickness, source function, Doppler width, and line-of-sight velocity. Using these measurements, the number density of hydrogen atoms in levels 1 and 2, total particle density, electron density, temperature, gas pressure, and mass density parameters were determined with the method of Tsiropoula & Schmieder (1997). We also analyzed the temporal behaviour of a mottle using cloud parameters. Our result shows that it is dominated by 3 minute signals in source function, and 5 minutes or more in velocity.

Bostanci, Z. F.

2011-10-01

33

H$\\alpha$ kinematics of KPG 390  

CERN Document Server

In this work we present scanning Fabry-Perot H$\\alpha$ observations of the isolated interacting galaxy pair NGC 5278/79 obtained with the PUMA Fabry-Perot interferometer. We derived velocity fields, various kinematic parameters and rotation curves for both galaxies. Our kinematical results together with the fact that dust lanes have been detected in both galaxies, as well as the analysis of surface brightness profiles along the minor axis, allowed us to determine that both components of the interacting pair are trailing spirals.

Repetto, P; Fuentes-Carrera, R Gabbasov I

2009-01-01

34

H-alpha variability in Alpha Lyrae  

International Nuclear Information System (INIS)

Observations of Alpha Lyr obtained in a 36-nm band centered on H-alpha using a rapid-scanning spectrophotometer with entrance slit 120 microns, exit slit 250 microns, FWHM resolution 650 pm, and scan duration 4.28 min at the Cassegrain focus of the 61-cm reflecting telescope at Yerkes Observatory over 17.5 h on six nights spanning 43 days in July-August 1984, are reported. A typical scan is presented graphically, and no variability of the type observed by Goraya and Singh (1983) in October 1983, is found

1985-01-01

35

New perspectives on strong z=0.5 MgII absorbers: are halo-mass and equivalent width anti-correlated?  

CERN Document Server

We measure the mean halo-mass of z=0.5 MgII absorbers using the cross-correlation (over co-moving scales 0.05-13h^{-1}Mpc) between 1806 MgII quasar absorption systems and ~250,000 Luminous Red Galaxies (LRGs), both selected from the SDSS DR3. The MgII systems have rest-frame equivalent widths W_r(2796)>=0.3A. From the ratio of the MgII-LRG cross-correlation to the LRG-LRG auto-correlation, we find that the bias ratio between MgII absorbers and LRGs is 0.65+/-0.08, which implies that the absorber host-galaxies have a mean halo-mass 20-40 times smaller than that of the LRGs; the MgII absorbers have halos of mean mass =11.94+/-0.31(stat)+/-0.25(sys). We demonstrate that this statistical technique, which does not require any spectroscopic follow-up, does not suffer from contaminants such as stars or foreground and background galaxies. Finally, we find that the absorber halo-mass is anti-correlated with the equivalent width. If MgII absorbers were virialized in galaxy halos a positive M_h-W_r correlation would hav...

Bouche, N; Peroux, C; Csabai, I; Wild, V; Bouche, Nicolas; Murphy, Michael T.; Peroux, Celine; Csabai, Istvan; Wild, Vivienne

2006-01-01

36

Deneb: Five Years of H Alpha Monitoring  

Science.gov (United States)

Ritter Observatory's archive of spectra of Deneb covers the period 1993 through the present. In an initial survey of the archival data, we studied the H alpha region of 339 spectra taken during the 1997-2001 observing seasons with the 1-meter telescope and its fiber-fed spectrograph, which has a spectral resolving power of 26,000. The present results are based on inspection of dynamical spectra constructed with IRAF and SAOImage DS9. Telluric absorption lines have been removed. The H alpha profile has a P Cygni morphology, with an emission component that is highly variable in strength. Superimposed on blue wing of the absorption component, there is almost always a secondary absorption feature at a radial velocity of about -100 km s-1. Sometimes the feature progresses to more negative velocities, as do DACs in P Cygni wind lines in hotter stars, but sometimes the feature remains stationary. In 1997, it exhibited cyclical behavior, with ``absorption events'' occurring approximately every 40 days. There is subtle evidence of similar behavior in 2000, but in the other years, the waxing and waning of the feature appear to be largely stochastic. Research at Ritter Observatory is supported by The University of Toledo, the Fund for Astrophysical Research, and the American Astronomical Society Small Grants Program (NASA funds). Community access to the facility is supported by NSF-PREST. Allgaier's participation was supported by the NSF-REU program.

Morrison, N. D.; Richardson, N. D.; Allgaier, E.

2005-05-01

37

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

CERN Document Server

We discovered an H alpha absorption in a broad H alpha emission line of an unusual broad absorption line quasar, SDSS J083942.11+380526.3 at z=2.318, by near-infrared spectroscopy with the Cooled Infrared Spectrograph and Camera for OHS (CISCO) on the Subaru telescope. The Presence of non-stellar H alpha absorption is known only in the Seyfert galaxy NGC 4151 to date, thus our discovery is the first case for quasars. The H alpha absorption line is blueshifted by 520 km/s relative to the H alpha emission line, and its redshift almost coincides with those of UV low-ionization metal absorption lines. The width of the H alpha absorption (~ 340 km/s) is similar to those of the UV low-ionization absorption lines. These facts suggest that the H alpha and the low-ionization metal absorption lines are produced by the same low-ionization gas which has a substantial amount of neutral gas. The column density of the neutral hydrogen is estimated to be ~ 10^18 cm^-2 by assuming a gas temperature of 10,000 K from the analys...

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

2006-01-01

38

A Ly? EMITTER WITH AN EXTREMELY LARGE REST-FRAME EQUIVALENT WIDTH OF ?900 Å AT z = 6.5: A CANDIDATE POPULATION III-DOMINATED GALAXY?  

International Nuclear Information System (INIS)

We have identified a very interesting Ly? emitter (LAE), whose Ly? emission line has an extremely large observed equivalent width of EW0 = 436+422–149 Å, which corresponds to an extraordinarily large intrinsic rest-frame equivalent width of EWint0 = 872+844–298 Å after the average intergalactic absorption correction. The object was spectroscopically confirmed to be a real LAE by its apparent asymmetric Ly? line profile detected at z = 6.538. The continuum emission of the object was definitely detected in our deep z'-band image; thus, its EW0 was reliably determined. Follow-up deep near-infrared spectroscopy revealed emission lines of neither He II ?1640 as an apparent signature of Population III (Pop III) nor C IV ?1549 as proof of an active nucleus. No detection of the short-lived He II ?1640 line is not necessarily inconsistent with the interpretation that the underlying stellar population of the object is dominated by Pop III. We found that the observed extremely large EW0 of the Ly? emission and the upper limit on the EW0 of the He II ?1640 emission can be explained by population synthesis models favoring a very young age less than 2-4 Myr and massive metal-poor (Z –5) or even metal-free stars. The observed large EW0 of Ly? is insufficiently explained by Population I/II synthesis models with Z ? 10–3. However, we cannot conclusively rule out the possibility that this object is composed of a normal stellar population with a clumpy dust distribution, which could enhance the Ly? EW0, though its significance is still unclear.

2012-12-20

39

A Ly? Emitter with an Extremely Large Rest-frame Equivalent Width of ~900 Å at z = 6.5: A Candidate Population III-dominated Galaxy?  

Science.gov (United States)

We have identified a very interesting Ly? emitter (LAE), whose Ly? emission line has an extremely large observed equivalent width of EW0 = 436+422 - 149 Å, which corresponds to an extraordinarily large intrinsic rest-frame equivalent width of EWint 0 = 872+844 - 298 Å after the average intergalactic absorption correction. The object was spectroscopically confirmed to be a real LAE by its apparent asymmetric Ly? line profile detected at z = 6.538. The continuum emission of the object was definitely detected in our deep z'-band image; thus, its EW0 was reliably determined. Follow-up deep near-infrared spectroscopy revealed emission lines of neither He II ?1640 as an apparent signature of Population III (Pop III) nor C IV ?1549 as proof of an active nucleus. No detection of the short-lived He II ?1640 line is not necessarily inconsistent with the interpretation that the underlying stellar population of the object is dominated by Pop III. We found that the observed extremely large EW0 of the Ly? emission and the upper limit on the EW0 of the He II ?1640 emission can be explained by population synthesis models favoring a very young age less than 2-4 Myr and massive metal-poor (Z = 10-3. However, we cannot conclusively rule out the possibility that this object is composed of a normal stellar population with a clumpy dust distribution, which could enhance the Ly? EW0, though its significance is still unclear. Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan, and 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.

Kashikawa, Nobunari; Nagao, Tohru; Toshikawa, Jun; Ishizaki, Yoshifumi; Egami, Eiichi; Hayashi, Masao; Ly, Chun; Malkan, Matthew A.; Matsuda, Yuichi; Shimasaku, Kazuhiro; Iye, Masanori; Ota, Kazuaki; Shibuya, Takatoshi; Jiang, Linhua; Taniguchi, Yoshiaki; Shioya, Yasuhiro

2012-12-01

40

Comparing Ultraviolet and H alpha Star Formation Rates  

CERN Document Server

We have used a sample of 43 star-forming galaxies imaged in the far-ultraviolet (FUV) by the UIT supplemented with 33 galaxies observed by FAUST, to explore the consistency of UV and H alpha derived star formation rates (SFRs). We find, even before correction for dust, that UV and H alpha SFRs are quantitatively consistent for low-luminosity galaxies, and that higher luminosity galaxies have H alpha SFRs a factor of 1.5 higher than their UV SFRs: this reflects the influence of dust. Our results are consistent with a scenario where the UV dust extinction is a factor of less than 2 larger than the H alpha dust extinction in a given galaxy, and that there is over a 4 magnitude range of H alpha dust extinctions which correlate loosely with galaxy luminosity such that low luminosity galaxies tend to have lower extinctions than their higher luminosity counterparts.

Bell, E F

2000-01-01

 
 
 
 
41

Surge observed in H alpha and C IV  

International Nuclear Information System (INIS)

Results are presented of simultaneous measurements of H-alpha (MSDP at Meudon) and C IV (UVSP onboard SMM) of Active Region 2701 made on October 2, 1980. Isodensity and velocity maps were obtained for both lines and these maps were superimposed. Results show a good correlation between the H-alpha and C IV velocities with a surge being observed for 10 minutes. The base of the surge was determined to be located in a bright point in C IV and H-alpha, while the escaping matter followed the same channel (absorbing in H-alpha, emitting in C IV). It was found that the velocity along the surge was about 80 km/s in H-alpha and 100 km/s in C IV. In addition, a loop appeared in C IV during the surge. It is concluded that the vertical pressure gradient was capable of driving the surge

1982-06-02

42

On the origins of the diffuse H-alpha emission: Ionized gas or dust-scattered H-alpha halos?  

CERN Document Server

It is known that the diffuse H-alpha emission outside of bright H II regions not only are very extended, but also can occur in distinct patches or filaments far from H II regions, and the line ratios of [S II] 6716/H-alpha and [N II] 6583/H-alpha observed far from bright H II regions are generally higher than those in the H II regions. These observations have been regarded as evidence against the dust-scattering origin of the diffuse H-alpha emission (including other optical lines), and the effect of dust scattering has been neglected in studies on the diffuse H-alpha emission. In this paper, we reexamine the arguments against dust scattering and find that the dust-scattering origin of the diffuse H-alpha emission cannot be ruled out. As opposed to the previous contention, the expected dust- scattered H-alpha halos surrounding H II regions are, in fact, in good agreement with the observed H-alpha morphology. We calculate an extensive set of photoionization models by varying elemental abundances, ionizing stel...

Seon, Kwang-Il

2012-01-01

43

Scattered H-alpha light from Galactic dust clouds  

CERN Document Server

Bright emission nebulae, or HII regions, around hot stars are readily seen in H-alpha light. However, the all-pervasive faint H-alpha emission has only recently been detected and mapped over the whole sky. Mostly the H-alpha emission observed along a line of sight is produced by ionised gas in situ. There are, however, cases where all or most of the H-alpha radiation is due to scattering by electrons or dust particles which are illuminated by an H-alpha emitting source off the line of sight. Here we demonstrate that diffuse, translucent and dark dust clouds at high galactic latitudes are in many cases observed to have an excess of diffuse H-alpha surface brightness, i.e. they are brighter than the surrounding sky. We show that the majority of this excess surface brightness can be understood as light scattered off the interstellar dust grains. The source of incident photons is the general Galactic H-alpha background radiation impinging on the dust clouds from all over the sky.

Mattila, K; Lehtinen, K

2006-01-01

44

Behavior of H-alpha in Delta Cephei  

International Nuclear Information System (INIS)

A new radial velocity curve for Delta Cep is presented based on 10 A/mm red spectrograms. The curves for neutral metallic lines, low excitation ions, and high excitation Si II lines follow the curve of Shane (1958) within observational uncertainties. For H-alpha the curve shows an amplitude 15 km/s larger than for the metallic lines. Arguments are presented to show that the H-alpha absorption is formed high in the atmosphere of Delta Cep

1979-01-01

45

Dynamic fibrils in H-alpha and C IV  

CERN Document Server

Aim: To study the interaction of the solar chromosphere with the transition region, in particular active-region jets in the transition region and their relation to chromospheric fibrils. Methods: We carefully align image sequences taken simultaneously in C IV with the Transition Region and Coronal Explorer and in H-alpha with the Swedish 1-m Solar Telescope. We examine the temporal evolution of "dynamic fibrils", i.e., individual short-lived active-region chromospheric jet-like features in H-alpha. Results: All dynamic fibrils appear as absorption features in H-alpha that progress from the blue to the red wing through the line, and often show recurrent behavior. Some of them, but not all, appear also as bright features in C IV which develop at or just beyond the apex of the H-alpha darkening. They tend to best resemble the H-alpha fibril at +700 mA half a minute earlier. Conclusions: Dynamic chromospheric fibrils observed in H-alpha regularly correspond to transition-region jets observed in the ultraviolet. T...

de Wijn, A G

2006-01-01

46

Starbursts and Extra-planar H-alpha from SINGG  

CERN Document Server

The NOAO Survey for Ionization in Neutral Gas Galaxies (SINGG) is the largest star formation survey of an HI selected sample. Since the selection is made without regard to optical morphology, it is not biased toward or against "interesting" types of galaxies; thus SINGG is an ideal sample for studying galaxy demographics. Of a sample of 90 extra-galactic sources observed in photometric conditions, all are detected in H-alpha. This indicates that dormant galaxies, those containing an appreciable ISM but no star formation, are at best rare. We have made first pass morphological surveys for starbursts, as judged by H-alpha surface brightness, and outflows as judged by extra-planar H-alpha. We find that about 15% of the sources contain starbursts, with little dependence on the neutral hydrogen mass MHI. Nearly one half of a sample ~35 edge-on galaxies show evidence for extra-planar H-alpha having a scale size of 0.5 Kpc or larger, while nearly one quarter have extra-planar H-alpha features 1.0 Kpc in size or larg...

Meurer, G R

2003-01-01

47

Flux calibration of the AAO/UKST SuperCOSMOS H-alpha Survey  

CERN Document Server

The AAO/UKST SuperCOSMOS H-alpha Survey (SHS) of the southern Galactic plane was, when completed in 2003, a powerful new addition to wide-field surveys. It has a combination of areal coverage, spatial resolution and flux sensitivity in a narrow imaging band which still marks it out today as an excellent resource for the astronomical community. The 233 separate fields are available online in digital form, with each field covering 25 square degrees. The SHS has been the motivation for equivalent surveys in the north, and new digital H-alpha surveys now beginning in the south such as VPHAS+. The SHS has been the foundation of many important follow-up discovery projects in the southern sky with the Macquarie/AAO/Strasbourg H-alpha (MASH) planetary nebula project being a particularly successful example. However, the full astrophysical potential of the SHS has been hampered by lack of a clear route to acceptable flux calibration from the base photographic data. We have determined the calibration factors for 170 sep...

Frew, David J; Parker, Quentin A; Pierce, Mark J; Gunawardhana, M L P; Reid, W A

2013-01-01

48

H{alpha} ABSORPTION IN TRANSITING EXOPLANET ATMOSPHERES  

Energy Technology Data Exchange (ETDEWEB)

Absorption of stellar H{alpha} by the upper atmosphere of the planet HD 189733b has recently been detected by Jensen et al. Motivated by this observation, we have developed a model for atomic hydrogen in the n = 2 state and compared the resulting H{alpha} line profile to the observations. The model atmosphere is in hydrostatic balance, as well as thermal and photoionization equilibrium. Collisional and radiative transitions are included in the determination of the n = 2 state level population. We find that H{alpha} absorption is dominated by an optical depth {tau} {approx} 1 shell, composed of hydrogen in the metastable 2s state that is located below the hydrogen ionization layer. The number density of the 2s state within the shell is found to vary slowly with radius, while that of the 1s state falls rapidly. Thus while the Ly{alpha} absorption, for a certain wavelength, occurs inside a relatively well defined impact parameter, the contribution to H{alpha} absorption is roughly uniform over the entire atomic hydrogen layer. The model can approximately reproduce the observed Ly{alpha} and H{alpha} integrated transit depths for HD 189733b by using an ionization rate enhanced over that expected for the star by an order of magnitude. For HD 209458b, we are unable to explain the asymmetric H{alpha} line profile observed by Jensen et al., as the model produces a symmetric line profile with transit depth comparable to that of HD 189733b. In an appendix, we study the effect of the stellar Ly{alpha} absorption on the net cooling rate.

Christie, Duncan; Arras, Phil; Li Zhiyun, E-mail: dac5zm@virginia.edu, E-mail: pla7y@virginia.edu, E-mail: zl4h@virginia.edu [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States)

2013-08-01

49

Impact of non-LTE effects on the IR Ca II triplet and the Mg I 8736 Å equivalent widths in late-type giant and super-giant stars  

Science.gov (United States)

Calcium and magnesium are key ?-elements to study stellar populations in galaxies. Classical stellar abundances analyses rely on the local thermodynamic equilibrium (LTE) assumption which is not always appropriate, in particular for metal-poor and/or evolved stars. To better understand these stars and apprehend their impacts on the chemical enrichment of the Galaxy, it is necessary to use a Non-LTE (NLTE) description which is more realistic but also more complex to build up. For the calcium (Ca) and magnesium (Mg) lines in the RVS@Gaia, we computed theoretical NLTE corrections to apply to the measured equivalent widths of these lines using very complete model atoms of Mg and Ca. These corrections can be used by the automated abundance analysis methods based on equivalent widths for current and forthcoming large surveys.

Merle, T.; Thévenin, F.; Pichon, B.; Bigot, L.

2012-12-01

50

H\\alpha\\ Emission Variability in Active M Dwarfs  

CERN Document Server

We use ~12,000 spectra of ~3,500 magnetically active M0-M9 dwarfs from the Sloan Digital Sky Survey taken at 10-15 minute intervals, together with ~300 spectra of ~60 M0-M8 stars obtained hourly with the Hydra multi-object spectrometer, to probe H\\alpha\\ variability on timescales of minutes to weeks. With multiple observations for every star examined, we are able to characterize fluctuations in H\\alpha emission as a function of activity strength and spectral type. Stars with greater magnetic activity (as quantified by L_H\\alpha/L_bol) are found to be less variable at all spectral types. We attribute this result to the stronger level of persistent emission in the high activity stars, requiring a larger heating event in order to produce measurable variability. We also construct H\\alpha\\ structure functions to constrain the timescale of variability. The more active objects with lower variability exhibit a characteristic timescale longer than an hour, likely due to larger, longer lasting heating events, while the...

Bell, Keaton J; Davenport, James R A; Hawley, Suzanne L; West, Andrew A; Rogel, Allen B

2011-01-01

51

Filament and Flare Detection in H{\\alpha} image sequences  

CERN Multimedia

Solar storms can have a major impact on the infrastructure of the earth. Some of the causing events are observable from ground in the H{\\alpha} spectral line. In this paper we propose a new method for the simultaneous detection of flares and filaments in H{\\alpha} image sequences. Therefore we perform several preprocessing steps to enhance and normalize the images. Based on the intensity values we segment the image by a variational approach. In a final postprecessing step we derive essential properties to classify the events and further demonstrate the performance by comparing our obtained results to the data annotated by an expert. The information produced by our method can be used for near real-time alerts and the statistical analysis of existing data by solar physicists.

Riegler, Gernot; Pötzi, Werner; Veronig, Astrid

2013-01-01

52

CHaS, the Circumgalactic H-alpha Spectrograph  

Science.gov (United States)

CHaS (the Circumgalactic H-alpha Spectrograph) is a new narrowband Integral Field Unit (IFU) spectrograph, developed by the Schiminovich Group at Columbia University in 2013. CHaS will be used to map the H-alpha emission from diffuse, low surface brightness gas around nearby galaxies as well as Galactic nebulae. A small prototype for CHaS was debuted on the 1.3m and 2.4m telescopes at MDM Observatory, on Kitt Peak, Arizona, during September, 2013. Proto-CHaS uses a microlens array placed in the image plane, which produces a 6 x 6 (3x3) arcminute spectral image of the target composed of 5 (2.5) arcsecond pixels. Each pixel is a 3nm wide spectrum centered around either H-alpha or NII emission lines, depending on the filter chosen, with 2000. We present initial findings from the proto-type run, as well as predictions for the final, larger version of CHaS.

Gordon, Sam; Schiminovich, D.; Hamden, E. T.

2014-01-01

53

H-alpha Spectral diversity of type II supernovae  

CERN Document Server

We present a spectroscopic analysis of the H-alpha profiles of hydrogen-rich type II supernovae. A total of 52 type II supernovae having well sampled optical light curves and spectral sequences were analyzed. Concentrating on the H-alpha P-Cygni profile we measure its velocity from the FWHM of emission and the ratio of absorption to emission (a/e) at a common epoch at the start of the recombination phase, and search for correlations between these spectral parameters and photometric properties of the V-band light curves. Testing the strength of various correlations we find that a/e appears to be the dominant spectral parameter in terms of describing the diversity in our measured supernova properties. It is found that supernovae with smaller a/e have higher H-alpha velocities, more rapidly declining light curves from maximum, during the plateau and radioactive tail phase, are brighter at maximum light and have shorter optically thick phase durations. We discuss possible explanations of these results in terms of...

Gutiérrez, Claudia P; Hamuy, Mario; González-Gaitán, Santiago; Folatelli, Gastón; Morrell, Nidia I; Stritzinger, Maximilian D; Phillips, Mark M; McCarthy, Patrick; Suntzeff, Nicholas B; Thomas-Osip, Joanna

2014-01-01

54

A Survey for H$\\alpha$ Pulsar Bow Shocks  

CERN Document Server

We report on a survey for H$\\alpha$ bow shock emission around nearby $\\gamma$-detected energetic pulsars. This survey adds three Balmer-dominated neutron star bow shocks to the six previously confirmed examples. In addition to the shock around {\\it Fermi} pulsar PSR J1741$-$2054, we now report H$\\alpha$ structures around two additional $\\gamma$-ray pulsars, PSR J2030+4415 and PSR J1509$-$5850. These are the first known examples of H$\\alpha$ nebulae with pre-ionization halos. With new measurements, we show that a simple analytic model can account for the angular size and flux of the bow shocks' apices. The latter, in particular, provides a new pulsar probe and indicates large moments of inertia and smaller distances than previously assumed, in several cases. In particular we show that the re-measured PSR J0437$-$4715 shock flux implies $I = (1.7\\pm 0.2) \\times 10^{45}/(f_{HI} {\\rm sin}i) {\\rm g\\,cm^2}$. We also derive a distance $d\\approx 0.72$kpc for the $\\gamma$-ray only pulsar PSR J2030+4415 and revised dis...

Brownsberger, Sasha

2014-01-01

55

Star formation in spiral galaxies. I - H-alpha observations  

International Nuclear Information System (INIS)

This paper presents large-aperture photometric measurements of H-alpha + forbidden N II emission line strengths in 110 spiral galaxies. These galaxies represent three different samples of objects: (1) low surface brightness spiral galaxies; (2) galaxies of extreme arm classifications (flocculent versus grand design); and (3) galaxies with measured (B -H) colors which have been used to study the color-absolute magnitude relation for spiral galaxies. Details of the observations are given, and a comparison is made with previous work. Future papers will use this data to study the star-formation rates in the various samples. 13 refs

1990-01-01

56

The Aao/Ukst Supercosmos H-alpha Survey (SHS)  

CERN Document Server

The UK Schmidt Telescope (UKST) of the Anglo-Australian Observatory completed a narrow-band H-alpha plus [NII] 6548, 6584A survey of the Southern Galactic Plane and Magellanic Clouds in late 2003. The survey, which was the last UKST wide-field photographic survey, and the only one undertaken in a narrow band, is now an on-line digital data product of the Wide-Field Astronomy Unit of the Royal Observatory Edinburgh (ROE). The survey utilised a high specification, monolithic H-alpha interference band-pass filter of exceptional quality. In conjunction with the fine grained Tech-Pan film as a detector it has produced a survey with a powerful combination of area coverage (4000 square degrees), resolution (~1 arcsecond) and sensitivity (<=5 Rayleighs), reaching a depth for continuum point sources of R~20.5. The main survey consists of 233 individual fields on a grid of centres separated by 4 degrees at declinations below +2 degrees and covers a swathe approximately 20 degrees wide about the Southern Galactic Pla...

Parker, Q A; Pierce, M J; Hartley, M; Hambly, N C; Read, M A; MacGillivray, H T; Tritton, S B; Cass, C P; Cannon, R D; Cohen, M; Drew, J E; Frew, D J; Hopewell, E; Mader, S; Malin, D F; Masheder, M R W; Morgan, D H; Morris, R A H; Russeil, D; Russell, K S; Walker, R N F

2005-01-01

57

OPTICAL SPECTROSCOPY OF H{alpha} FILAMENTS IN COOL CORE CLUSTERS: KINEMATICS, REDDENING, AND SOURCES OF IONIZATION  

Energy Technology Data Exchange (ETDEWEB)

We have obtained deep, high spatial and spectral resolution, long-slit spectra of the H{alpha} nebulae in the cool cores of nine galaxy clusters. This sample provides a wealth of information on the ionization state, kinematics, and reddening of the warm gas in the cool cores of galaxy clusters. We find evidence for only small amounts of reddening in the extended, line-emitting filaments, with the majority of filaments having E(B - V) < 0.2. We find, in agreement with previous works, that the optical emission in cool core clusters has elevated low-ionization line ratios. The combination of [O III]/H{beta}, [N II]/H{alpha}, [S II]/H{alpha}, and [O I]/H{alpha} allow us to rule out collisional ionization by cosmic rays, thermal conduction, and photoionization by intracluster medium (ICM) X-rays and active galactic nuclei as strong contributors to the ionization in the bulk of the optical line-emitting gas in both the nuclei and filaments. The data are adequately described by a composite model of slow shocks and star formation. This model is further supported by an observed correlation between the line widths and low-ionization line ratios which becomes stronger in systems with more modest star formation activity based on far-ultraviolet observations. We find that the more extended, narrow filaments tend to have shallower velocity gradients and narrower line widths than the compact filamentary complexes. We confirm that the widths of the emission lines decrease with radius, from FWHM {approx}600 km s{sup -1} in the nuclei to FWHM {approx}100 km s{sup -1} in the most extended filaments. The variation of line width with radius is vastly different than what is measured from stellar absorption lines in a typical giant elliptical galaxy, suggesting that the velocity width of the warm gas may in fact be linked to ICM turbulence and, thus, may provide a glimpse into the amount of turbulence in cool cores. In the central regions (r < 10 kpc) of several systems the warm gas shows kinematic signatures consistent with rotation, consistent with earlier work. We find that the kinematics of the most extended filaments in this sample are broadly consistent with both infall and outflow, and recommend further studies linking the warm gas kinematics to both radio and X-ray maps in order to further understand the observed kinematics.

McDonald, Michael [Kavli Institute for Astrophysics and Space Research, MIT, Cambridge, MA 02139 (United States); Veilleux, Sylvain [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Rupke, David S. N., E-mail: mcdonald@space.mit.edu, E-mail: veilleux@astro.umd.edu, E-mail: rupked@rhodes.edu [Department of Physics, Rhodes College, Memphis, TN 38112 (United States)

2012-02-20

58

Spectral Properties From Lyman-alpha to H-alpha For An Essentially Complete Sample of Quasars I: Data  

CERN Multimedia

We have obtained quasi-simultaneous ultraviolet-optical spectra for 22 out of 23 quasars in the complete PG-X-ray sample with redshift, z<0.4, and M_B<-23. The spectra cover rest-frame wavelengths from at least Lyman-alpha to H-alpha. Here we provide a detailed description of the data, including careful spectrophotometry and redshift determination. We also present direct measurements of the continua, strong emission lines and features, including Lyman-alpha, SiIV+OIV], CIV, CIII], SiIII], MgII, H-beta, [OIII], He5876+NaI5890,5896, H-alpha, and blended iron emission in the UV and optical. The widths, asymmetries and velocity shifts of profiles of strong emission lines show that CIV and Lyman-alpha are very different from H-beta and H-alpha. This suggests that the motion of the broad line region is related to the ionization structure, but the data appears not agree with the radially stratified ionization structure supported by reverberation mapping studies, and therefore suggest that outflows contribute a...

Shang, Z; Wills, D; Brotherton, M S; Shang, Zhaohui; Wills, Beverley J.; Brotherton, Michael S.

2007-01-01

59

Group Width  

CERN Document Server

There are many "minimax" complexity functions in mathematics: width of a tree or a link, Heegaard genus of a 3-manifold, the Cheeger constant of a Riemannian manifold. We define such a function w, "width", on countable (or finite) groups and show w(Z^k) = k-1.

Freedman, Michael H

2010-01-01

60

A Ly{alpha} EMITTER WITH AN EXTREMELY LARGE REST-FRAME EQUIVALENT WIDTH OF {approx}900 A AT z = 6.5: A CANDIDATE POPULATION III-DOMINATED GALAXY?  

Energy Technology Data Exchange (ETDEWEB)

We have identified a very interesting Ly{alpha} emitter (LAE), whose Ly{alpha} emission line has an extremely large observed equivalent width of EW{sub 0} = 436{sup +422}{sub -{sub 149}} A, which corresponds to an extraordinarily large intrinsic rest-frame equivalent width of EW{sup int}{sub 0} = 872{sup +844}{sub -{sub 298}} A after the average intergalactic absorption correction. The object was spectroscopically confirmed to be a real LAE by its apparent asymmetric Ly{alpha} line profile detected at z = 6.538. The continuum emission of the object was definitely detected in our deep z'-band image; thus, its EW{sub 0} was reliably determined. Follow-up deep near-infrared spectroscopy revealed emission lines of neither He II {lambda}1640 as an apparent signature of Population III (Pop III) nor C IV {lambda}1549 as proof of an active nucleus. No detection of the short-lived He II {lambda}1640 line is not necessarily inconsistent with the interpretation that the underlying stellar population of the object is dominated by Pop III. We found that the observed extremely large EW{sub 0} of the Ly{alpha} emission and the upper limit on the EW{sub 0} of the He II {lambda}1640 emission can be explained by population synthesis models favoring a very young age less than 2-4 Myr and massive metal-poor (Z < 10{sup -5}) or even metal-free stars. The observed large EW{sub 0} of Ly{alpha} is insufficiently explained by Population I/II synthesis models with Z {>=} 10{sup -3}. However, we cannot conclusively rule out the possibility that this object is composed of a normal stellar population with a clumpy dust distribution, which could enhance the Ly{alpha} EW{sub 0}, though its significance is still unclear.

Kashikawa, Nobunari; Hayashi, Masao; Iye, Masanori [Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Nagao, Tohru; Ota, Kazuaki [Department of Astronomy, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Toshikawa, Jun; Ishizaki, Yoshifumi; Shibuya, Takatoshi [Department of Astronomy, School of Science, Graduate University for Advanced Studies, Mitaka, Tokyo 181-8588 (Japan); Egami, Eiichi; Jiang, Linhua [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Ly, Chun [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Malkan, Matthew A. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States); Matsuda, Yuichi [Radio Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Shimasaku, Kazuhiro [Department of Astronomy, University of Tokyo, Hongo, Tokyo 113-0033 (Japan); Taniguchi, Yoshiaki; Shioya, Yasuhiro, E-mail: n.kashikawa@nao.ac.jp [Research Center for Space and Cosmic Evolution, Ehime University, Bunkyo-cho, Matsuyama 790-8577 (Japan)

2012-12-20

 
 
 
 
61

Equivalent widths of DIBs (Puspitarini+, 2013)  

Science.gov (United States)

We use high-resolution (R~~48000), high signal-to-noise (S/N>=100) spectra of nearby, early-type (B to A5), fast-rotating stars that are mostly located within 400pc. Observations were done with the FEROS spectrograph at the ESO/Max Planck 2.2m telescope in La Silla and were part of the LP179.C-0197 program. (1 data file).

Puspitarini, L.; Lallement, R.; Chen, H.-C.

2013-10-01

62

The interacting galaxy pair KPG 390: H$\\alpha$ kinematics  

CERN Document Server

In this work we present scanning Fabry-Perot H$\\alpha$ observations of the isolated interacting galaxy pair NGC 5278/79 obtained with the PUMA Fabry-Perot interferometer. We derived velocity fields and rotation curves for both galaxies. For NGC 5278 we also obtained the residual velocity map to investigate the non-circular motions, and estimated its mass by fitting the rotation curve with a disk+halo components. We test three different types of halo (pseudo-isothermal, Hernquist and Navarro Frenk White) and obtain satisfactory fits to the rotation curve for all profiles. The amount of dark matter required by pseudo-isothermal profile is about ten times smaller than, that for the other two halo distributions. Finally, our kinematical results together with the analysis of dust lanes distribution and of surface brightness profiles along the minor axis allowed us to determine univocally that both components of the interacting pair are trailing spirals.

Repetto, P; Gabbasov, R; Fuentes-Carrera, I

2010-01-01

63

Observational Tests to Detect Photometric Reverberation in H-alpha  

Science.gov (United States)

We present photometric observations of several AGN that were secured with the 0.9-m telescope located at the West Mountain Observatory that is operated by Brigham Young University. The new observations use standard BVR filters along with several custom filters that are part of a red shifted H-alpha set. Light curves are presented for several of the targets along with a summary of the analysis made to detect lag times between the continuum and broad emission line flux as evidence for photometric reverberation. Plans are presented for future research that will continue along these lines.We thank the Department of Physics and Astronomy along with the College of Physical and Mathematical Sciences at Brigham Young University for continued support of the research work being done at the West Mountain Observatory.

Joner, Michael D.; Carroll, Carla

2014-06-01

64

Channel widths  

International Nuclear Information System (INIS)

At the request of SKB, BERGAB-Berggeologiska Undersoekningar AB have carried out a study of documented water leakage in two TBM tunnels. The hydrogeological mapping of the tunnels include a classification of leakage according to flowrate and width. This report is based upon the hydrogeological mapping and gives a further analysis of the documented data. The objective is to study the distribution of flowrates and leak widths in channels. Further the object has been to examine if the flowrates are dependent of the widths. (authors)

1991-01-01

65

The H-alpha light curves of novae in M31  

Science.gov (United States)

H-alpha and B light curves are presented for 11 M31 novae, four of which were well observed near maximum. These data, along with the H-alpha light curves of two Galactic novae, demonstrate that a nova's maximum H-alpha flux occurs days or weeks after its continuum maximum at a monochromatic intensity 1-2 magnitudes above its peak flux in B. Moreover, after this maximum is achieved, a typical nova will radiate a third as many photons in H-alpha as in the entire B bandpass. The most interesting part of a nova's H-alpha light curve, however, is its decline. It is found that, regardless of a nova's speed, its H-alpha decay rate after maximum is almost identical to its decay rate in B. This behavior suggests that most of a nova's optical luminosity during early decline is continuum emission from the nebula, rather than direct radiation from the central source.

Ciardullo, Robin; Shafter, Allen W.; Ford, Holland C.; Neill, James D.; Shara, Michael M.

1990-01-01

66

An H-alpha survey of the rich cluster A1689  

Digital Repository Infrastructure Vision for European Research (DRIVER)

(Abridged) We present results of an H-alpha survey in the rich cluster A1689 at z=0.18, using the LDSS++ spectrograph on the AAT. We obtained spectra covering redshifted H-alpha for 522 galaxies brighter than I=22.5, covering a field of 8.7'X8.7'. We detect H-alpha emission in 46 of these galaxies; accounting for selection effects due to sampling and cluster membership, we determine that 24% of cluster members brighter than M_R=-16.5+5log(h) are detected with H-alpha flux gr...

Balogh, Michael; Couch, Warrick J.; Smail, Ian; Bower, Richard G.; Glazebrook, Karl

2002-01-01

67

Uncovering the Outflow Driven by the Brown Dwarf LS-RCr A1: H-alpha as a Tracer of Outflow Activity in Brown Dwarfs  

CERN Multimedia

It is now apparent that classical T Tauri-like outflows commonly accompany the formation of young brown dwarfs. To date two optical outflows have been discovered and results presented in this paper increase this number to three. Using spectro-astrometry the origin of the LS-RCrA 1 forbidden emission lines in a blue-shifted outflow is confirmed. The non-detection of the red-shifted component of the outflow in forbidden lines, along with evidence for some separation between low and high velocity outflow components, do not support the hypothesis that LS-RCrA 1 has an edge-on accretion disk. The key result of this analysis is the discovery of an outflow component to the H-alpha line. The H-alpha line profile has blue and red-shifted features in the wings which spectro-astrometry reveals to also originate in the outflow. The discovery that H-alpha emission in BDs can have a significant contribution from an outflow suggests the use of H-alpha line widths as a proxy of mass accretion in BDs is not clear-cut. This me...

Whelan, E T; Bacciotti, F

2009-01-01

68

A Study on Red Asymmetry of H-alpha Flare Ribbons Using Narrowband Filtergram in the 2001 April 10 Solar Flare  

CERN Multimedia

We report a detailed examination of the "red asymmetry" of H-alpha emission line seen during the 2001 April 10 solar flare by using a narrowband filtergram. We investigated the temporal evolution and the spatial distribution of the red asymmetry by using the H-alpha data taken with the 60cm Domeless Solar Telescope at Hida Observatory, Kyoto University. We confirmed that the red asymmetry clearly appeared all over the flare ribbons, and the strong red asymmetry is located on the outer narrow edges of the flare ribbons, with the width of about 1.5" - 3.0" (1000 - 2000 km), where the strong energy releases occur. Moreover, we found that the red asymmetry, which also gives a measure of the Doppler shift of the H-alpha emission line concentrates on a certain value, not depending on the intensity of the H-alpha kernels. This implies not only that the temporal evolutions of the red asymmetry and those of the intensity are not in synchronous in each flare kernel, but also that the peak asymmetry (or velocity of the ...

Asai, Ayumi; Kitai, Reizaburo; Kurokawa, Hiroki; Shibata, Kazunari

2011-01-01

69

Properties of the H-alpha-emitting Circumstellar Regions of Be Stars  

CERN Document Server

Long-baseline interferometric observations obtained with the Navy Prototype Optical Interferometer of the H-alpha-emitting envelopes of the Be stars eta Tauri and beta Canis Minoris are presented. For compatibility with the previously published interferometric results in the literature of other Be stars, circularly symmetric and elliptical Gaussian models were fitted to the calibrated H-alpha observations. The models are sufficient in characterizing the angular distribution of the H-alpha-emitting circumstellar material associated with these Be stars. To study the correlations between the various model parameters and the stellar properties, the model parameters for eta Tau and beta CMi were combined with data for other Be stars from the literature. After accounting for the different distances to the sources and stellar continuum flux levels, it was possible to study the relationship between the net H-alpha emission and the physical extent of the H-alpha-emitting circumstellar region. A clear dependence of the...

Tycner, C; Hajian, A R; Armstrong, J T; Benson, J A; Gilbreath, G C; Hutter, D J; Pauls, T A; White, N M; Tycner, Christopher; Lester, John B.; Hajian, Arsen R.

2005-01-01

70

The interstellar medium of M31. III - Narrow-band imagery in H alpha and (SII)  

Science.gov (United States)

Deep CCD imagery in H alpha and (SII) is presented of the major spiral arms of M31 with particular attention given to the data reduction and the analysis of the (SII)/H alpha flux ratios. A diffuse ionized gas noted in the images is analyzed which shows higher (SII)/H alpha ratios, and 967 discrete nebulae are listed with gray-scale images, finding charts, and absolute fluxes. The differential H-alpha luminosity function is found to have a slope of -0.95 for brighter objects and flattens out below a critical level. The curve is shown to correspond to the point at which single-star ionization accounts for the H alpha luminosities and is consistent with previous observations. The catalog of objects and fluxes is the largest existing sample of this type, and the unresolved objects in the sample are considered to be planetary nebulae.

Walterbos, R. A. M.; Braun, R.

1992-01-01

71

Evidence for energizing of H. alpha. emission in type II supernovae by ejecta-wind interaction  

Energy Technology Data Exchange (ETDEWEB)

A simple one-zone model of H{alpha} luminosity of late time type II supernovae, energized by {sup 56}Co-{sup 56}Fe decay, was applied to the analysis of the observed H{alpha} evolution. Of the six available SNeII with known H{alpha} fluxes at late times, three reveal the extra H{alpha} flux above the radioactive model. This excess is interpreted as an effect of an energy release due to ejecta-wind interaction. Two SNeII, 1979C and 1987F, with the particularly strong H{alpha} excess, show additional spectroscopic signatures, which can be attributed to the dense wind around supernovae. (author).

Chugai, N.N. (AN SSSR, Moscow (USSR). Astronomicheskij Sovet)

1991-06-01

72

The H alpha Galaxy Survey VI. Star-forming companions of nearby field galaxies  

CERN Multimedia

We present a search for star-forming satellite galaxies that are close enough to their parent galaxies to be considered analogues of the Magellanic Clouds. Our search technique relied on the detection of the satellites in continuum-subtracted narrow-band H alpha imaging of the central galaxies, which removes most of the background and foreground line-of-sight companions, thus giving a high probability that we are detecting true satellites. The search was performed for 119 central galaxies at distances between 20 and 40 Mpc, although spatial incompleteness means that we have effectively searched 53 full satellite-containing volumes. We find only 9 probable star-forming satellites, around 9 different central galaxies, and 2 possible satellites. After incompleteness correction, this is equivalent to 0.17/0.21 satellites per central galaxy. The Small Magellanic Cloud is just below the median values of both star formation rate and R-band luminosity of the 9 probable satellites. The Large Magellanic Cloud, however,...

James, P A; Shane, N S

2008-01-01

73

The clustering of H-alpha emitters at z=2.23 from HiZELS  

CERN Multimedia

(abridged) We present a clustering analysis of 370 high-confidence H-alpha emitters (HAEs) at z=2.23. The HAEs are detected in the Hi-Z Emission Line Survey (HiZELS), a large-area blank field 2.121um narrowband survey using the United Kingdom Infrared Telescope (UKIRT) Wide Field Camera (WFCAM). Averaging the two-point correlation function of HAEs in two ~1 degree scale fields (United Kingdom Infrared Deep Sky Survey/Ultra Deep Survey [UDS] and Cosmological Evolution Survey [COSMOS] fields) we find a clustering amplitude equivalent to a correlation length of r_0=3.7+/-0.3 Mpc/h for galaxies with star formation rates of >7 M_sun/yr. The data are well-fitted by the expected correlation function of Cold Dark Matter, scaled by a bias factor: omega_HAE=b^2 omega_DM where b=2.4^{+0.1}_{-0.2}. The corresponding 'characteristic' mass for the halos hosting HAEs is log(M_h/[M_sun/h])=11.7+/-0.1. Comparing to the latest semi-analytic GALFORM predictions for the evolution of HAEs in a LCDM cosmology, we find broad agreem...

Geach, J E; Hickox, R C; Wake, D A; Smail, Ian; Best, P N; Baugh, C M; Stott, J P

2012-01-01

74

Structure and star formation in disk galaxies III. Nuclear and circumnuclear H alpha emission  

CERN Document Server

From H alpha images of a carefully selected sample of 57 relatively large, Northern spiral galaxies with low inclination, we study the distribution of the H alpha emission in the circumnuclear and nuclear regions. At a resolution of around 100 parsec, we find that the nuclear H alpha emission in the sample galaxies is often peaked, and significantly more often so among AGN host galaxies. The circumnuclear H alpha emission, within a radius of two kpc, is often patchy in late-type, and absent or in the form of a nuclear ring in early-type galaxies. There is no clear correlation of nuclear or circumnuclear H alpha morphology with the presence or absence of a bar in the host galaxy, except for the nuclear rings which occur in barred hosts. The presence or absence of close bright companion galaxies does not affect the circumnuclear H alpha morphology, but their presence does correlate with a higher fraction of nuclear H alpha peaks. Nuclear rings occur in at least 21% (+-5%) of spiral galaxies, and occur predomina...

Knapen, J H

2004-01-01

75

The H-alpha and Infrared Star Formation Rates for the Nearby Field Galaxy Survey  

CERN Multimedia

We investigate the H-alpha and infrared star formation rate (SFR) diagnostics for galaxies in the Nearby Field Galaxy Survey (NFGS). For the 93 galaxies in our sample, we derive H-alpha fluxes (included here) from integrated spectra which typically cover 82% of each galaxy. There is a strong correlation between the ratio of infrared to optical star-formation rates SFR(IR)/SFR(H-alpha) and the extinction E(B-V) measured with the Balmer decrement. Before reddening correction, the SFR(IR) and SFR(H-alpha) are related to each other by a power-law. Correction of the SFR(H-alpha) for extinction using the Balmer decrement and a classical reddening curve both reduces the scatter in the SFR(IR)-SFR(H-alpha) correlation and results in a much closer agreement between the two SFR indicators. This SFR relationship spans 4 orders of magnitude and holds for all Hubble types with IRAS detections in the NFGS. A constant ratio between the SFR(IR) and SFR(H-alpha) for all Hubble types, including early types (S0-Sab), suggests t...

Kewley, L J; Jansen, R A; Dopita, M A

2002-01-01

76

Observatons of NGC 3077 Galaxy in Narrow Band [SII] and H_alpha Filters  

CERN Document Server

We present observations of the HI tidal arm near dwarf galaxy NGC 3077 (member of the M81 galaxy group) in narrow band [SII] and H_alpha filters. Observations were carried out in March 2011 with the 2m RCC telescope at NAO Rozhen, Bulgaria. Our search for possible supernova remnant candidates (identified as sources with enhanced [SII] emission relative to their H_alpha emission) in this region yielded no sources of this kind. Nevertheless, we found a number of objects with significant H_alpha emission that probably represent uncatalogued, low brightness HII regions.

Andjelic, M; Arbutina, B; Ilic, D; Urosevic, D

2011-01-01

77

A Dual Narrowband Survey for H\\alpha\\ Emitters at z=2.2: Demonstration of the Technique and Constraints on the H\\alpha\\ Luminosity Function  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present first results from a narrowband imaging program for intermediate redshift emission-line galaxies using the newly commissioned FourStar infrared camera at the 6.5m Magellan telescope. To enable prompt identification of H\\alpha\\ emitters, a pair of custom 1% filters, which sample low-airglow atmospheric windows at 1.19 \\mu m and 2.10 \\mu m, is used to detect both H\\alpha\\ and [OII]\\lambda 3727 emission from the same redshift volume at z=2.2. Initial observations are...

Lee, Janice C.; Ly, C.; Spitler, L.; Labbe, I.; Salim, S.; Persson, S. E.; Ouchi, M.; Dale, D.; Monson, A.; Murphy, D.

2012-01-01

78

Constraining Disk Parameters of Be Stars using Narrowband H-alpha Interferometry with the NPOI  

CERN Document Server

Interferometric observations of two well-known Be stars, gamma Cas and phi Per, were collected and analyzed to determine the spatial characteristics of their circumstellar regions. The observations were obtained using the Navy Prototype Optical Interferometer equipped with custom-made narrowband filters. The filters isolate the H-alpha emission line from the nearby continuum radiation, which results in an increased contrast between the interferometric signature due to the H-alpha-emitting circumstellar region and the central star. Because the narrowband filters do not significantly attenuate the continuum radiation at wavelengths 50 nm or more away from the line, the interferometric signal in the H-alpha channel is calibrated with respect to the continuum channels. The observations used in this study represent the highest spatial resolution measurements of the H-alpha-emitting regions of Be stars obtained to date. These observations allow us to demonstrate for the first time that the intensity distribution in...

Tycner, C; Benson, J A; Gilbreath, G C; Hajian, A R; Hutter, D J; Jones, C E; Pauls, T A; White, N M; Zavala, R T

2006-01-01

79

Correlations between MIR, FIR, H$\\alpha$, and FUV Luminosities for SWIRE galaxies  

CERN Document Server

e present and analyze the correlations between mid-infrared (MIR), far-infrared (FIR), total-infrared (TIR), H$\\alpha$, and FUV luminosities for star-forming galaxies, composite galaxies and AGNs, based on a large sample of galaxies selected from the $Spitzer$ SWIRE fields. The MIR luminosities of star-forming galaxies are well correlated with their H$\\alpha$, TIR and FUV luminosities, and we re-scaled the MIR-derived SFR formulae according to the above correlations with differences less than 15%. We confirm the recent result by calzetti et al. (2007) that the combined observed H$\\alpha$ + 24$\\mu$m luminosities L(H$\\alpha IR and TIR luminosities are completely following those of star-forming galaxies.

Zhu, Yi-Nan; Cao, Chen; Li, Hai-Ning

2008-01-01

80

Spatially Resolved H(alpha)-Emitting Wind Structure of P Cygni.  

Science.gov (United States)

High spatial resolution observations of the H(alpha)-emitting wind structure associated with the luminous blue variable star P Cygni were obtained with the Navy Prototype Optical Interferometer. These observations represent the most comprehensive interfer...

A. Balan C. Tycner D. J. Hutter J. A. Benson R. T. Zavala

2010-01-01

 
 
 
 
81

Constraints on supernova progenitors from spatial correlations with H-alpha emission  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have attempted to constrain the progenitors of all supernova types, through correlations of the positions of historical supernovae with recent star formation, as traced by H-alpha emission. Through pixel statistics we have found that a large fraction of the SNII population do not show any association with current star formation, which we put down to a 'runaway' fraction of these progenitors. The SNIb/c population accurately traces the H-alpha emission, with some suggestio...

Anderson, J. P.; James, P. A.; Salaris, M.; Percival, S. M.

2007-01-01

82

H-alpha variability of the recurrent nova T Coronae Borealis  

CERN Document Server

We analyze H-alpha observations of the recurrent nova T CrB obtained during the last decade. For the first time the H-alpha emission profile is analyzed after subtraction of the red giant contribution. Based on our new radial velocity measurements of the H-alpha emission line we estimate the component masses of T CrB. It is found that the hot component is most likely a massive white dwarf. We estimate the inclination and the component masses to be i~67 deg, Mwd = 1.37 +/-0.13 Msun and Msec=1.12 +/-0.23 Msun, respectively. The radial velocity of the central dip in the H-alpha profile changes nearly in phase with that of the red giant's absorption lines. This suggests that the dip is most likely produced by absorption in the giant's wind. Our observations cover an interval when the H-alpha and the U-band flux vary by a factor of ~6, while the variability in B and V is much smaller. Based on our observations, and archival ultraviolet and optical data we show that the optical, ultraviolet and H-alpha fluxes stron...

Stanishev, V; Tomov, N; Marziani, P

2003-01-01

83

NEBULAR ATTENUATION IN H{alpha}-SELECTED STAR-FORMING GALAXIES AT z = 0.8 FROM THE NewH{alpha} SURVEY  

Energy Technology Data Exchange (ETDEWEB)

We present measurements of the dust attenuation of H{alpha}-selected emission-line galaxies at z = 0.8 from the NewH{alpha} narrowband survey. The analysis is based on deep follow-up spectroscopy with Magellan/IMACS, which captures the strong rest-frame optical emission lines from [O II] {lambda}3727 to [O III] {lambda}5007. The spectroscopic sample used in this analysis consists of 341 confirmed H{alpha} emitters. We place constraints on the active galactic nucleus (AGN) fraction using diagnostics that can be applied at intermediate redshift. We find that at least 5% of the objects in our spectroscopic sample can be classified as AGNs and 2% are composite, i.e., powered by a combination of star formation and AGN activity. We measure the dust attenuation for individual objects from the ratios of the higher order Balmer lines. The H{beta} and H{gamma} pair of lines is detected with S/N > 5 in 55 individual objects and the H{beta} and H{delta} pair is detected in 50 individual objects. We also create stacked spectra to probe the attenuation in objects without individual detections. The median attenuation at H{alpha} based on the objects with individually detected lines is A(H{alpha}) = 0.9 {+-} 1.0 mag, in good agreement with the attenuation found in local samples of star-forming galaxies. We find that the z = 0.8 galaxies occupy a similar locus of attenuation as a function of magnitude, mass, and star formation rate (SFR) as a comparison sample drawn from the SDSS DR4. Both the results from the individual z = 0.8 galaxies and from the stacked spectra show consistency with the mass-attenuation and SFR-attenuation relations found in the local universe, indicating that these relations are also applicable at intermediate redshift.

Momcheva, Ivelina G. [Astronomy Department, Yale University, New Haven, CT 06511 (United States); Lee, Janice C.; Ouchi, Masami [Carnegie Observatories, Pasadena, CA 91101 (United States); Ly, Chun [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Salim, Samir [Astronomy Department, Indiana University, Bloomington, IN 47405 (United States); Dale, Daniel A. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Finn, Rose [Physics Department, Siena College, Loudonville, NY 12211 (United States); Ono, Yoshiaki, E-mail: ivelina.momcheva@yale.edu [Department of Astronomy, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2013-02-01

84

H-$\\alpha$ Imaging of Early-type(Sa-Sab) Spiral Galaxies, 1  

CERN Multimedia

H-alpha and continuum images are presented for 27 nearby early-type(Sa-Sab) spiral galaxies. Contrary to popular perception, the images reveal copious massive star formation in some of these galaxies. A determination of the H-alpha morphology and a measure of the H-alpha luminosity suggests that early-type spirals can be classified into two broad categories based on the luminosity of largest HII region in the disk. The first category includes galaxies for which the individual HII regions have L(H-alpha) 10^(39) erg/s. All category 2 galaxies show either prominent dust lanes or other morphological peculiarities such as tidal tails which suggests that the anomalously luminous HII regions in category 2 galaxies may have formed as a result of a recent interaction. The observations, which are part of an on-going H-alpha survey, reveal early-type spirals to be a heterogeneous class of galaxies that are evolving in the current epoch. We have also identified some systematic differences between the classifications of...

Hameed, S A; Hameed, Salman; Devereux, Nick

1999-01-01

85

A Dual Narrowband Survey for H\\alpha\\ Emitters at z=2.2: Demonstration of the Technique and Constraints on the H\\alpha\\ Luminosity Function  

CERN Document Server

We present first results from a narrowband imaging program for intermediate redshift emission-line galaxies using the newly commissioned FourStar infrared camera at the 6.5m Magellan telescope. To enable prompt identification of H\\alpha\\ emitters, a pair of custom 1% filters, which sample low-airglow atmospheric windows at 1.19 \\mu m and 2.10 \\mu m, is used to detect both H\\alpha\\ and [OII]\\lambda 3727 emission from the same redshift volume at z=2.2. Initial observations are taken over a 130 arcmin^2 area in the CANDELS-COSMOS field. The exquisite image quality resulting from the combination of the instrument, telescope, and standard site conditions (~0.55" FWHM) allows the 1.19 \\mu m and 2.10 \\mu m data to probe 3\\sigma\\ emission-line depths down to 1.0e-17 erg/s/cm^2 and 1.2e-17 erg/s/cm^2 respectively, in less than 10 hours of integration time in each narrowband. For H\\alpha\\ at z=0.8 and z=2.2, these fluxes correspond to observed star formation rates of ~0.3 and ~4 Msun/yr respectively. We find 122 source...

Lee, Janice C; Spitler, L; Labbe, I; Salim, S; Persson, S E; Ouchi, M; Dale, D; Monson, A; Murphy, D

2012-01-01

86

Nebular Attenuation in H\\alpha-selected Star-forming Galaxies at z=0.8 from the NewH\\alpha\\ Survey  

CERN Document Server

We present measurements of the dust attenuation of H\\alpha-selected emission-line galaxies at z=0.8 from the NewH\\alpha\\ narrowband survey. The analysis is based on deep follow-up spectroscopy with Magellan/IMACS, which captures the strong rest-frame optical emission lines from [OII] \\lambda 3727 to [OIII] \\lambda 5007. The spectroscopic sample used in this analysis consists of 341 confirmed H\\alpha\\ emitters. We place constraints on the AGN fraction using diagnostics which can be applied at intermediate redshift. We find that at least 5% of the objects in our spectroscopic sample can be classified as AGN and 2% are composite, i.e. powered by a combination of star-formation and AGN activity. We measure the dust attenuation for individual objects from the ratios of the higher order Balmer lines. The H\\beta\\ and H\\gamma\\ pair of lines is detected with S/N>5 in 55 individual objects and the H\\beta\\ and H\\delta\\ pair is detected in 50 individual objects. We also create stacked spectra to probe the attenuation in ...

Momcheva, Ivelina; Ly, Chun; Salim, Samir; Dale, Daniel A; Ouchi, Masami; Finn, Rose; Ono, Yoshiaki

2012-01-01

87

An $H_{\\alpha}$ Catalogue of Galaxies in Hickson Compact Groups; 1, The Sample  

CERN Document Server

We present H$_\\alpha$ photometry for a sample of 95 galaxies in Hickson Compact Groups obtained from observations of 31 groups. The Catalogue lists isophotal and adaptive aperture (Kron aperture) flux measurements for about 75% of the accordant galaxies inside the observed HCGs, 22 out of which are upper limits. Non standard data reduction procedures have been used to obtain the continuum subtracted H$_\\alpha$ images for each HCG of the target sample. Flux calibration has also been performed in order to obtain H$_\\alpha$ luminosities for the whole sample. Both the data reduction and calibration procedures are carefully described in this paper. The new data listed in this Catalogue are of great importance in understanding the star formation rate inside HCG galaxies and in giving new insights on its dependence on galaxy interactions.

Severgnini, P; Saracco, P; Chincarini, G L

1999-01-01

88

Far-infrared characteristics of K dwarfs with H-alpha emission  

International Nuclear Information System (INIS)

A sample of K dwarfs with H-alpha emission have counterparts in the IRAS Point Source Catalog. They show two types of infrared spectral behavior, either net decline of emergent flux density from 0.55 micron to at least 12 microns, approximately like normal K dwarfs without H-alpha emission, or net rise in this spectral range, as though with radiation from cool circumstellar matter. Behavior type is not well associated with H-alpha emission strength. Declining spectra are detectable with IRAS to about 30 pc, but rising spectra are not found in this volume so they must be less abundant. Stars with rising spectra may be associated with nebulosity, but one of them, TW Hya, is an exception to the later dependence. 25 references

1986-01-01

89

Polarized Broad H-$\\alpha$ Emission from the LINER Nucleus of NGC 1052  

CERN Document Server

Optical spectropolarimetry of the nucleus of the LINER NGC 1052, obtained at the Keck Observatory, reveals a rise in polarization in the wings of the H-alpha line profile. The polarization vector of H-alpha is offset by 67 degrees from the parsec-scale radio axis and by 83 degrees from the kiloparsec-scale radio axis, roughly in accord with expectations for scattering within the opening cone of an obscuring torus. The broad component of H-alpha has FWHM ~ 2100 km/s in total flux and FWHM ~ 5000 km/s in polarized light. Scattering by electrons is the mechanism most likely responsible for this broadening, and we find T_e ~ 10^5 K for the scattering medium, similar to values observed in Seyfert 2 nuclei. This is the first detection of a polarized broad emission line in a LINER, demonstrating that unified models of active galactic nuclei are applicable to at least some LINERs.

Barth, A J; Moran, E C

1999-01-01

90

A Deep, Wide-Field H-alpha Survey of Nearby Clusters of Galaxies  

CERN Document Server

We present a progress report on an ongoing H-alpha imaging survey of nearby clusters of galaxies. Four clusters have been surveyed to date: A1367, A1656, A347 and A569. A preliminary comparison of H-alpha luminosity functions obtained from our imaging survey with those from the prism survey reveals a significant level of incompleteness in the latter. This in turn is due to a combination of insensitivity to low-luminosity emission-line galaxies and to brighter galaxies with weak extended H-alpha emission. The survey has also revealed a unique population of clustered dwarf emission-line objects which may be the results of recent tidal encounters between larger gas-rich galaxies.

Sakai, S; Moss, C; Sakai, Shoko; Kennicutt, Robert; Moss, Chris

2000-01-01

91

MONITORING H{alpha} EMISSION AND CONTINUUM OF UXORs: RR Tauri  

Energy Technology Data Exchange (ETDEWEB)

The Maria Mitchell Observatory, in collaboration with the Astrokolkhoz Observatory, started a program of photometric monitoring of UX Ori-type stars (UXORs) with narrowband interference filters (IFs; augmented with the traditional broadband filters) aimed at separating the H{alpha} emission variations from those of the continuum. We present the method of separation and the first results for RR Tau obtained in two seasons, each roughly 100 days long (2010 Winter-Spring and 2010 Fall-2011 Spring). We confirm the conclusion from previous studies that the H{alpha} emission in this star is less variable than the continuum. Although some correlation between the two is not excluded, the amplitude of H{alpha} variations is much smaller (factors of 3-5) than that of the continuum. These results are compatible with Grinin's model of UXORs, which postulates the presence of small obscuring circumstellar clouds as the cause of the continuum fading, as well as the presence of a circumstellar reflection/emission nebula, larger than the star and the obscuring clouds, which is responsible for H{alpha} emission and the effect of the 'color reversal' in deep minima. However, the results of both our broadband and narrowband photometry indicate that the obscuration model may be insufficient to explain all of the observations. Disk accretion, the presence of stellar or (proto) planetary companion(s), as well as the intrinsic variations of the star, may contribute to the observed light variations. We argue, in particular, that the H{alpha} emission may be more closely correlated with the intrinsic variations of the star than with the much stronger observed variations caused by the cloud obscuration. If this hypothesis is correct, the close monitoring of H{alpha} emission with IFs, accessible to small-size telescopes, may become an important tool in studying the physical nature of the UXORs' central stars.

Bedell, Megan; Villaume, Alexa; Weiss, Lauren; Sliski, David; Strelnitski, Vladimir; Walker, Gary; Williams, Jedediyah [Maria Mitchell Observatory, 4 Vestal Street, Nantucket, MA 02554 (United States); Henden, Arne [AAVSO, 49 Bay State Road, Cambridge, MA 02138 (United States); Krajci, Tom [Astrokolkhoz Observatory, P.O. Box 1351, Cloudcroft, NM 88317 (United States)

2011-11-15

92

H$\\alpha$ and Free-Free Emission from the WIM  

CERN Document Server

Recent observations have found the ratio of H$\\alpha$ to free-free radio continuum to be surprisingly high in the diffuse ionized ISM (the so-called WIM), corresponding to an electron temperature of only $\\sim$3000~K. Such low temperatures were unexpected in gas that was presumed to be photoionized. We consider a 3-component model for the observed diffuse emission, consisting of a mix of (1) photoionized gas, (2) gas that is recombining and cooling, and (3) cool H~I gas. This model can successfully reproduce the observed intensities of free-free continuum, H$\\alpha$, and collisionally-excited lines such as [\\ion{N}{2}]6583. To reproduce the low observed value of free-free to H$\\alpha$, the PAH abundance in the photoionized regions must be lowered by a factor $\\sim$3, and $\\sim$15\\% of the diffuse H$\\alpha$ must be reflected from dust grains, as suggested by \\citet{Wood+Reynolds_1999}.

Dong, Ruobing

2010-01-01

93

UBV photometry of new H-alpha stars in the association Orion OB1d  

Energy Technology Data Exchange (ETDEWEB)

UBV data are given for 92 new stars with H-alpha in emission found recently by Parsamyan and Chavira (1982) in the association Orion OB1d. The limiting magnitude in U is 17.7m. The positions of these stars in the Hertzsprung-Russell diagram and in the two-color (U - B, B - V) diagram are given. 9 references.

Gasparian, K.G.

1985-09-01

94

The Properties of H{\\alpha} Emission-Line Galaxies at $z$ = 2.24  

CERN Document Server

Using deep narrow-band $H_2S1$ and $K_{s}$-band imaging data obtained with CFHT/WIRCam, we identify a sample of 56 H$\\alpha$ emission-line galaxies (ELGs) at $z=2.24$ with the 5$\\sigma$ depths of $H_2S1=22.8$ and $K_{s}=24.8$ (AB) over 383 arcmin$^{2}$ area in the ECDFS. A detailed analysis is carried out with existing multi-wavelength data in this field. Three of the 56 H$\\alpha$ ELGs are detected in Chandra 4 Ms X-ray observation and two of them are classified as AGNs. The rest-frame UV and optical morphologies revealed by HST/ACS and WFC3 deep images show that nearly half of the H$\\alpha$ ELGs are either merging systems or with a close companion, indicating that the merging/interacting processes play a key role in regulating star formation at cosmic epoch z=2-3; About 14% are too faint to be resolved in the rest-frame UV morphology due to high dust extinction. We estimate dust extinction form SEDs. We find that dust extinction is generally correlated with H$\\alpha$ luminosity and stellar mass (SM). Our res...

An, F X; Wang, W -H; Huang, J -S; Kong, X; Wang, J -X; Fang, G W; Zhu, F; Gu, Q -S; Wu, H; Hao, L; Xia, X -Y

2014-01-01

95

H alpha Star Formation Rates in Massive Galaxies at z ~ 1  

CERN Document Server

We present a near-infrared spectroscopic study of a stellar mass selected sample of galaxies at z~1 utilising the LIRIS multi-object spectrograph on the WHT. We detect continuum, and the H alpha line for our sample, which is one of the better direct tracers of star formation in external galaxies. We spectroscopically measure the H alpha emission from 41 massive (M_{*}>10^{10.5} Msol) galaxies taken from the POWIR Survey with spectroscopic redshifts 0.410^{11} Msol which are detected in H alpha emission at z<0.9. We furthermore find that the fraction of galaxies with H alpha emission drops steadily and significantly with redder (U-B) colours at z~1, and that the SSFR drops with increasing (U-B) colour for galaxies at all masses. By investigating the SFR-mass relation we find that the SFR is roughly constant with mass, in possible contrast to previous work, and that the specific star formation rate (SSFR) is lower in the most massive galaxies. The scatter in the SFR vs. mass relationship is very small for th...

Twite, Jonathan W; Buitrago, Fernando; Noeske, Kai; Weiner, Benjamin J; Acosta-Pulido, Jose A; Bauer, Amanda E

2011-01-01

96

Existence of oscillations in solar filaments observed in H alpha and C IV lines  

International Nuclear Information System (INIS)

Time sequence observations of filaments in both the H alpha line and the 1548 A C IV line were analyzed with the Fourier transform technique in the frequency range (1 - 10 mHz). No oscillation is detected in filaments except at the footpoints where a steady velocity gradient is large. The energy is probably due to convective motions rather than pressure oscillations

1986-12-01

97

First Simultaneous Observation of H-alpha Moreton Wave, EUV Wave, and Filament/Prominence Oscillations  

CERN Multimedia

We report on the first simultaneous observation of an H-alpha Moreton wave, the corresponding EUV fast coronal waves, and a slow and bright EUV wave (typical EIT wave). Associated with an X6.9 flare that occurred on 2011 August 9 at the active region NOAA 11263, we observed a Moreton wave in the H-alpha images taken by the Solar Magnetic Activity Research Telescope (SMART) at Hida Observatory of Kyoto University. In the EUV images obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO) we found not only the corresponding EUV fast "bright" coronal wave, but also the EUV fast "faint" wave that is not associated with the H-alpha Moreton wave. We also found a slow EUV wave, which corresponds to a typical EIT wave. Furthermore, we observed, for the first time, the oscillations of a prominence and a filament, simultaneously, both in the H-alpha and EUV images. To trigger the oscillations by the flare-associated coronal disturbance, we expect a coronal wave as fast as the fast...

Asai, Ayumi; Isobe, Hiroaki; Kitai, Reizaburo; UeNo, Satoru; Nagata, Shin'ichi; Morita, Satoshi; Nishida, Keisuke; Shiota, Daikou; Oi, Akihito; Akioka, Maki; Shibata, Kazunari

2011-01-01

98

DISCOVERY OF AN H{alpha} EMITTING DISK AROUND THE SUPERMASSIVE BLACK HOLE OF M31  

Energy Technology Data Exchange (ETDEWEB)

Due to its proximity, the mass of the supermassive black hole in the nucleus of the Andromeda galaxy (M31), the most massive black hole in the Local Group of galaxies, has been measured by several methods involving the kinematics of a stellar disk which surrounds it. We report here the discovery of an eccentric H{alpha} emitting disk around the black hole at the center of M31 and show how modeling this disk can provide an independent determination of the mass of the black hole. Our model implies a mass of 5.0{sup +0.8}{sub -1.0} Multiplication-Sign 10{sup 7} M{sub Sun} for the central black hole, consistent with the average of determinations by methods involving stellar dynamics, and compatible (at 1{sigma} level) with measurements obtained from the most detailed models of the stellar disk around the central black hole. This value is also consistent with the M-{sigma} relation. In order to make a comparison, we applied our simulation on the stellar kinematics in the nucleus of M31 and concluded that the parameters obtained for the stellar disk are not formally compatible with the parameters obtained for the H{alpha} emitting disk. This result suggests that the stellar and the H{alpha} emitting disks are intrinsically different from each other. A plausible explanation is that the H{alpha} emission is associated with a gaseous disk. This hypothesis is supported by the detection of traces of weaker nebular lines in the nuclear region of M31. However, we cannot exclude the possibility that the H{alpha} emission is, at least partially, generated by stars.

Menezes, R. B.; Steiner, J. E.; Ricci, T. V., E-mail: robertobm@astro.iag.usp.br [Instituto de Astronomia Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao 1226, Cidade Universitaria, Sao Paulo, SP CEP 05508-090 (Brazil)

2013-01-10

99

Variations of flaring kernel sizes in various parts of the H-alpha line profile  

CERN Document Server

We analyze the temporal variations of the sizes and emission intensities of thirtyone flaring kernels in various parts of the H{\\alpha} line profile. We have found that the areas of all kernels decrease systematically when observed in consecutive wavelengths toward the wings of the H{\\alpha} line, but their areas and emission intensity vary in time. Our results are in agreement with the commonly accepted model of the glass-shaped lower parts of the magnetic flaring loops channelling high energy variable particle beams toward the chromospheric plasma. High time resolution spectral-imaging data used in our work were collected using the Large Coronagraph and Horizontal Telescope equipped with the Multi-channel Subtractive Double Pass Spectrograph and the Solar Eclipse Coronal Imaging System (MSDP-SECIS) at the Bia{\\l}k\\'ow Observatory of the University of Wroc{\\l}aw, Poland.

Radziszewski, K

2012-01-01

100

H-alpha Emission Variability in the gamma-ray Binary LS I +61 303  

CERN Document Server

LS I +61 303 is an exceptionally rare example of a high mass X-ray binary (HMXB) that also exhibits MeV-TeV emission, making it one of only a handful of "gamma-ray binaries". Here we present H-alpha spectra that show strong variability during the 26.5 day orbital period and over decadal time scales. We detect evidence of a spiral density wave in the Be circumstellar disk over part of the orbit. The H-alpha line profile also exhibits a dramatic emission burst shortly before apastron, observed as a redshifted shoulder in the line profile, as the compact source moves almost directly away from the observer. We investigate several possible origins for this red shoulder, including an accretion disk, mass transfer stream, and a compact pulsar wind nebula that forms via a shock between the Be star's wind and the relativistic pulsar wind.

McSwain, M Virginia; Gies, Douglas R; Ray, Paul S

2010-01-01

 
 
 
 
101

H-alpha scans of the intergalactic H I cloud in Leo  

International Nuclear Information System (INIS)

Scans of H-alpha were obtained for two fields within the large, intergalactic H I cloud in Leo. The data provide a conservative upper limit of 1.7 x 10 to the -7th ergs/sq cm/s/sr on the H-alpha surface brightness of the cloud. This limit corresponds to an emission measure of less than 2 cm exp -6 pc for gas at a temperature of 10,000 K and implies an ionized hydrogen mass of less than 9 x 10 to the 9th f exp 1/2 solar mass within the cloud, where f is the filling fraction of the gas. This intensity may have important implications for possible sources of the ionization. 17 references

1986-01-01

102

H-alpha confirmation of two recent disc novae in M 31  

Science.gov (United States)

We obtained a set of 11x180s, 11x120s, and 11x60s dithered stacked CCD images of M 31, respectively, using Baader broad (7nm wide) H-alpha, Baader R and Baader clear (Cl) filters on 2011 July 5 with the Open University PIRATE Planewave CDK17 0.43m Dall-Kirkham f/6.7 telescope at the Observatorio Astronomico de Mallorca, Costitx, Spain, using an SBIG STX 16803 CCD Camera.

Burwitz, V.; Henze, M.; Pietsch, W.; Holmes, S.; Kolb, U.; Rodriguez, C. A. Haswell J.

2011-07-01

103

^{56}Ni mass in type IIP SNe: Light curves and H-alpha luminosities diagnostics  

CERN Document Server

We analyse late-time observations, available photometry and spectra, of a sample of type II plateau supernovae (SNe IIP). The possibility of using H$\\alpha$ luminosity at the nebular epoch as a tracer of $^{56}$Ni mass in this class of objects is investigated, yielding a consistency with the photometry-based estimates within 20%. Interesting correlations are found and their impacts on our present understanding of the physics of core collapse SNe are discussed.

Elmhamdi, A; Danziger, I J

2003-01-01

104

Small-scale H{\\alpha} Jets in the Solar Chromosphere  

CERN Multimedia

High temporal and spatial resolution observations from the Rapid Oscillations in the Solar Atmosphere (ROSA) multiwavelength imager on the Dunn Solar Telescope are used to study the velocities of small-scale H{\\alpha} jets in an emerging solar active region. The dataset comprises of simultaneous imaging in the H{\\alpha} core, Ca II K, and G band, together with photo- spheric line-of-sight magnetograms. Time-distance techniques are employed to determine projected plane-of-sky velocities. The H{\\alpha} images are highly dynamic in nature, with estimated jet velocities as high as 45 km s^{-1}. These jets are one-directional, with their origin seemingly linked to underlying Ca II K brightenings and G-band magnetic bright points. It is suggested that the siphon flow model of cool coronal loops is suitable for the interpretation of our observations. The jets are associated with small-scale explosive events, and may provide a mass outflow from the photosphere to the corona.

Kuridze, D; Jess, D B; Shelyag, S; Christian, D J; Keenan, F P; Balasubramaniam, K S

2011-01-01

105

An H-alpha nuclear spiral structure in the E0 active galaxy Arp102B  

CERN Document Server

We report the discovery of a two-armed mini-spiral structure within the inner kiloparsec of the E0 LINER/Seyfert 1 galaxy Arp102B. The arms are observed in H-alpha emission and located East and West of the nucleus, extending up to about 1 kpc from it. We use narrow-band imaging from the Hubble Space Telescope Advanced Camera for Surveys, in combination with archival VLA radio images at 3.6 and 6 cm to investigate the origin of the nuclear spiral. From the H-alpha luminosity of the spiral, we obtain an ionized gas mass of the order of one million solar masses. One possibility is that the nuclear spiral represents a gas inflow triggered by a recent accretion event which has replenished the accretion disk, giving rise to the double-peaked emission-line profiles characteristic of Arp102B. However, the radio images show a one-sided curved jet which correlates with the eastern spiral arm observed in the H-alpha image. A published milliarcsecond radio image also shows one-sided structure at position angle about 40 d...

Fathi, Kambiz; Storchi-Bergmann, Thaisa; Kharb, Preeti; Robinson, Andrew; Marconi, Alessandro; Maciejewski, Witold; Capetti, Alessandro

2011-01-01

106

Observational and theoretical constraints for an H$\\alpha$-halo around the Crab Nebula  

CERN Document Server

We searched for a fast moving H$\\alpha$ shell around the Crab nebula. Such a shell could account for this supernova remnant's missing mass, and carry enough kinetic energy to make SN 1054 a normal Type II event. Deep H$\\alpha$ images were obtained with WFI at the 2.2m MPG/ESO telescope and with MOSCA at the 2.56m NOT. The data are compared with theoretical expectations derived from shell models with ballistic gas motion, constant temperature, constant degree of ionisation and a power law for the density profile. We reach a surface brightness limit of $5\\times10^{-8} ergs s^{-1} cm^{-2} sr^{-1}$. A halo is detected, but at a much higher surface brightness than our models of recombination emission and dust scattering predict. Only collisional excitation of Ly$\\beta$ with partial de-excitation to H$\\alpha$ could explain such amplitudes. We show that the halo seen is due to PSF scattering and thus not related to a real shell. We also investigated the feasibility of a spectroscopic detection of high-velocity H$\\al...

Tziamtzis, A; Lundqvist, P; Sollerman, J

2009-01-01

107

A Search for "Dwarf" Seyfert Nuclei; 4, Nuclei with Broad H-$\\alpha$ Emission  

CERN Multimedia

We present the results of an optical spectroscopic survey designed to search for low-luminosity, "dwarf" Seyfert nuclei in a magnitude-limited sample of 486 bright, northern galaxies. Moderate-resolution spectra of exceptionally high quality were obtained in part to detect broad H-alpha emission, similar in character to, but much weaker than, the broad permitted lines that define type 1 Seyfert nuclei. One of the primary goals of the survey is to better quantify the faint end of the luminosity function of active galactic nuclei. This paper describes the subset of nuclei showing definite or probable evidence of broad H-alpha emission. We outline the procedures for determining the presence of this elusive spectral feature, steps for its quantitative measurement, and the associated systematic errors. Of the 211 emission-line galaxies classified as having Seyfert or LINER nuclei in our survey, the broad H-alpha line was detected with confidence in 34 objects, and with less certainty in another 12. Most of the det...

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

1997-01-01

108

Herschel reveals the obscured star formation in HiZELS H\\alpha\\ emitters at z=1.47  

CERN Document Server

We describe the far-infrared (FIR; rest-frame 8--1000\\mu m) properties of a sample of 443 H\\alpha-selected star-forming galaxies in the COSMOS and UDS fields detected by the HiZELS imaging survey. Sources are identified using narrow-band filters in combination with broad-band photometry to uniformly select H\\alpha\\ (and [OII] if available) emitters in a narrow redshift slice at z = 1.47+/-0.02. We use a stacking approach in Spitzer, Herschel (from PEP and HerMES surveys) and AzTEC images to describe their typical FIR properties. We find that HiZELS galaxies with observed H\\alpha\\ luminosities of ~ 10^{8.1-9.1} Lo have bolometric FIR luminosities of typical LIRGs, L_FIR ~ 10^{11.48+/-0.05} Lo. Combining the H\\alpha\\ and FIR luminosities, we derive median SFR = 32+/-5 Mo/yr and H\\alpha\\ extinctions of A(H\\alpha) = 1.0+/-0.2 mag. Perhaps surprisingly, little difference is seen in typical HiZELS extinction levels compared to local star-forming galaxies. We confirm previous empirical stellar mass (M*) to A(H\\alpha...

Ibar, E; Best, P N; Ivison, R J; Smail, I; Arumugam, V; Berta, S; Béthermin, M; Bock, J; Cava, A; Conley, A; Farrah, D; Floc'h, E Le; Lutz, D; Magdis, G; Magnelli, B; Ikarashi, S; Kohno, K; Marsden, G; Oliver, S J; Page, M J; Pozzi, F; Riguccini, L; Schulz, B; Seymour, N; Smith, A J; Symeonidis, M; Wang, L; Wardlow, J; Zemcov, M

2013-01-01

109

Optical Observations of M81 Galaxy Group in Narrow Band [SII] and H_alpha Filters: Holmberg IX  

Directory of Open Access Journals (Sweden)

Full Text Available We present observations of the nearby tidal dwarf galaxy Holmberg IX in M81 galaxy group in narrow band [SII] and H$alpha$ filters, carried out in March and November 2008 with the 2m RCC telescope at NAO Rozhen, Bulgaria. Our search for resident supernova remnants (identified as sources with enhanced [SII] emission relative to their H$alpha$ emission in this galaxy yielded no sources of this kind, besides M&H 10-11 or HoIX X-1. Nevertheless, we found a number of objects with significant H$alpha$ emission that probably represent uncatalogued HII regions.

Arbutina, B.

2009-12-01

110

Hubble Space Telescope H-alpha imaging of star-forming galaxies at z = 1-1.5: evolution in the size and luminosity of giant HII regions  

CERN Document Server

We present HST/WFC3 narrowband imaging of the H-alpha emission in a sample of eight gravitationally-lensed galaxies at z = 1 - 1.5. The magnification caused by the foreground clusters enables us to obtain a median source plane spatial resolution of 360pc, as well as providing magnifications in flux ranging from ~10x to ~50x. This enables us to identify resolved star-forming HII regions at this epoch and therefore study their H-alpha luminosity distributions for comparisons with equivalent samples at z ~ 2 and in the local Universe. We find evolution in the both luminosity and surface brightness of HII regions with redshift. The distribution of clump properties can be quantified with an HII region luminosity function, which can be fit by a power law with an exponential break at some cut-off, and we find that the cut-off evolves with redshift. We therefore conclude that `clumpy' galaxies are seen at high redshift because of the evolution of the cut-off mass; the galaxies themselves follow similar scaling relati...

Livermore, R C; Richard, J; Bower, R G; Ellis, R S; Swinbank, A M; Rigby, J R; Smail, Ian; Ebeling, H; Crain, R A

2012-01-01

111

Width of ? hypernuclear states  

International Nuclear Information System (INIS)

I present a theory of the observed narrow width of ? hypernuclear states, of the width measured in ? atoms, and of the strong absorption of ? hyperons produced in K"- absorption in nuclei. (orig./HSI)

1982-06-25

112

H-alpha imaging of the Local Volume galaxies I. The NGC 6946 galaxy group  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present new H-alpha imaging of all known dwarf irregular companions to NGC 6946: UGC 11583, KK 251, KK 252, KKR 55, KKR 56, Cepheus 1, KKR 59, and KKR 60. The galaxies span a range of blue absolute magnitudes of [-13.6, -17.6], relative gas content of [0.1, 2.5] M_sun/L_sun, current star formation activity of [0.2, 5.2]10^-2 M_sun yr^-1, and timescale to exhaust the current gas supply of [6, 86] Gyr.

Karachentsev, I. D.; Kajsin, S. S.; Tsvetanov, Z.; Ford, H.

2005-01-01

113

Panoramic H-alpha and mid-infrared mapping of star formation in a z=0.8 cluster  

CERN Multimedia

We present the first wide-field H-alpha imaging survey around the distant cluster RXJ1716.4+6708 at z=0.81 with a narrow-band filter on MOIRCS/Subaru, down to SFR(Ha)~1Msun/yr. Combining with a wide-field MIR imaging survey with AKARI, we compare the unobscured and obscured star formation activities in the cluster. We find that both H-alpha emitters and MIR galaxies avoid the cluster centre and their spatial distribution is quite similar. Most of the H-alpha emitters show blue colours, but we find some H-alpha emitters on the red sequence. The MIR galaxies tend to be systematically redder than the H-alpha emitters probably due to heavy dust extinction. Interestingly, the red H-alpha emitters and the red MIR galaxies (i.e. dusty red galaxies) are most commonly seen in the medium-density environment such as cluster outskirts, groups and filaments, where optical colours of galaxies change. We also find that A(Ha) exceeds ~3 in extreme cases and that such very dusty galaxies are also located in the medium-density...

Koyama, Yusei; Shimasaku, Kazuhiro; Hayashi, Masao; Okamura, Sadanori; Tanaka, Ichi; Tokoku, Chihiro

2009-01-01

114

Calibrating [OII] star-formation rates at z>1 from dual H\\alpha-[OII] imaging from HiZELS  

CERN Document Server

We investigate the relationship between H\\alpha\\ and [OII](\\lambda 3727) emission in faint star-forming galaxies at z=1.47 with dust uncorrected star formation rates (SFRs) down to 1.4 Msun/yr, using data in two narrow-bands from WFCAM/UKIRT and Suprime-Cam/Subaru. A stacking analysis allows us to investigate H\\alpha\\ emission flux from bright [OII] emitters as well as faint ones for which H\\alpha\\ is not individually detected, and to compare them with a large sample of local galaxies. We find that there is a clear, positive correlation between the average H\\alpha\\ and [OII] luminosities for [OII] emitters at z=1.47, with its slope being consistent with the local relation. [OII] emitters at z=1.47 have lower mean observed ratios of H\\alpha/[OII] suggesting a small but systematic offset (at 2.8\\sigma\\ significance) towards lower values of dust attenuation, A(H\\alpha)~0.35, than local galaxies. This confirms that [OII] selection tends to pick up galaxies which are significantly less dusty on average than H\\alph...

Hayashi, Masao; Best, Philip N; Smail, Ian; Kodama, Tadayuki

2012-01-01

115

Red Star Forming Galaxies and Their Environment at z=0.4 Revealed by Panoramic H-alpha Imaging  

CERN Multimedia

We present a wide-field H-alpha imaging survey of the rich cluster CL0939+4713 (Abell 851) at z=0.41 with Suprime-Cam on the Subaru Telescope, using the narrow-band filter NB921. The survey is sensitive to active galaxies with star formation rates down to ~0.3Msun/yr throughout the 27'x27' field, and we identified 445 H-alpha emitters along the large-scale structures around the cluster. Using this sample, we find that (1) the fraction of H-alpha emitters is a strong function of environment and shows a clear decline toward the cluster central region. We also find that (2) the color of H-alpha emitters is clearly dependent on environment. The majority of the H-alpha emitters have blue colors with B-I<2, but we find H-alpha emitters with red colors as well. Such red emitters are very rare in the cluster center or its immediate surrounding regions, while they are most frequently found in groups located far away from the cluster center. These groups coincide with the environment where a sharp transition in gala...

Koyama, Yusei; Nakata, Fumiaki; Shimasaku, Kazuhiro; Okamura, Sadanori

2011-01-01

116

Near- And Mid-Infrared Imaging Study of Young Stellar Objects around LkH$\\alpha$ 234  

CERN Document Server

We present high-resolution ($0\\farcs2$) near-infrared images of the area surrounding the Herbig Be star LkH$\\alpha$ 234 taken with the Coronagraphic Imager with Adaptive Optics (CIAO) and the adaptive optics on the Subaru Telescope. The near-infrared ($J$, $H$, $K$, $L'$ and $M'$ bands) images reveal circumstellar structures around LkH$\\alpha$ 234 in detail. Eight young stellar object (YSO) candidates (Object B, C, D, E, F, G, NW1, and NW2) were detected at 2$\\arcsec$--11$\\arcsec$ from LkH$\\alpha$ 234. Objects B and C are likely variable stars, which is consistent with a young evolutionary status. Three objects (LkH$\\alpha$ 234, NW1, and NW2) were identified in the 11.8 $\\micron$ (SiC) and 17.65 $\\micron$ images obtained with the Long Wavelength Spectrometer (LWS) on the Keck Telescope. NW1 and NW2 are thought to be embedded young stars. We suggest that NW1 and not LkH$\\alpha$ 234 is the source illuminating the reflection nebula west of LkH$\\alpha$ 234, although Object G may be another candidate. In our image...

Kato, Eri; Perrin, Marshall D; Shibai, Hiroshi; Itoh, Yusuke; Ootsubo, Takafumi

2011-01-01

117

An H-alpha search for over-dense regions at z=2.23  

CERN Document Server

We present the results of a narrow-band (H2S1, 2.121/0.021um) imaging search with WFCAM/UKIRT for H-alpha emitters around several potential signposts of rare (10^-7-10^-8 Mpc^-3) over-dense regions at z=2.23: an over-density of QSOs (2QZ cluster), a powerful, high-redshift radio galaxy (HzRG), and a concentration of submillimetre galaxies (SMGs) and optically faint radio galaxies (OFRGs). In total, we detect 137 narrow-band emitter candidates down to emission-line fluxes of 0.5-1 x 10^-16 erg s^-1 cm^-2, across a total area of 0.56 sq. degrees (2.1 x 10^5 comoving Mpc at z=2.23) in these fields. The BzK colours of the emitters suggest that at least 80% of our sample are likely to be H-alpha emitters (HAEs) at z=2.23. This is one of the largest HAE samples known at z>2. We find modest (~3-sigma) local over-densities of emitters associated with all the three targets. In the 2QZ cluster field, the emitters show a striking filamentary structure connecting four of the z=2.23 QSOs extending over 30Mpc (comoving). I...

Matsuda, Y; Geach, J E; Best, P N; Sobral, D; Tanaka, I; Ohta, K; Kurk, J; Iwata, I; Bielby, Rich; Wardlow, J L; Bower, R G; Fanidakis, N; Ivison, R J; Kodama, T; Yamada, T; Mawatari, K; Casali, M

2011-01-01

118

The Galactic Halo Ionizing Field and $H-\\alpha$ Distances to HVCs  

CERN Document Server

There has been much debate in recent decades as to what fraction of ionizing photons from star forming regions in the Galactic disk escape into the halo. The recent detection of the Magellanic Stream in optical line emission at the CTIO 4m and the AAT 3.9m telescopes may now provide the strongest evidence that at least some of the radiation escapes the disk completely. While the distance to the Magellanic Stream is uncertain, the observed H-alpha emission is most plausibly explained by photoionization due to hot, young stars. Our model requires that the mean Lyman-limit opacity perpendicular to the disk is tau close to unity. Within the context of this model, it now becomes possible to determine distances to high velocity clouds, and the 3D orientation of the Magellanic Stream. Here, we discuss complications of the model (e.g., porosity, topology), future tests, ongoing improvements, and the importance of H-alpha limb brightening from surface ionization. More speculatively, we propose a direct experiment for ...

Bland-Hawthorn, J

1998-01-01

119

Analysis of EUV, UV, and H-alpha Emission from Two Very Different Prominences  

Science.gov (United States)

We analyze the properties of a pair of prominences observed the UV and EUV in April 2004. One was a generally quiet prominence which exhibited a period of activation. Another was a large "coronal cloud" type prominence. Both were observed by SOHO/SUMER, TRACE, and in H$\\alpha$ by BBSO and MLSO. The quiet prominence was also observed by the SOHO/CDS instrument. TRACE and H$\\alpha$ data provide 2D images on with time cadences on the order of 1 minute. The SUMER data was taken from a single slit location with a 90 second cadence and included a number of lines spanning the temperature range 80,000 to 1.6 million K. This observing program was designed to allow us to study prominence dynamics . CDS raster data was taken with a slower cadence, in lines formed at temperatures from 20,000 - 1 million K. We combine these different data sets to analyze the thermal properties, including differential emission measures (DEMs), of these very different prominences, and compare the results to those of prominences previously analyzed by ourselves and others.

Kucera, T.; Landi, E.

2008-01-01

120

H{\\alpha} Kinematics of S4G spiral galaxies I. NGC 864  

CERN Multimedia

We present a study of the kinematics of the isolated spiral galaxy NGC 864, using H{\\alpha} Fabry-Perot data obtained with the GH{\\alpha}FaS instrument at the William Herschel Telescope in La Palma, complemented with images at 3.6 {\\mu}m, in the R band and in H{\\alpha} filter, and integral field spectroscopic data. The resulting data cubes and velocity maps allow the study of the kinematics of the galaxy, including in-depth investigations of the rotation curve, velocity moment maps, velocity residual maps, gradient maps and position-velocity diagrams. We find asymmetries in the velocity field in the bar zone, caused by non-circular motions, probably in response to the potential of the bar. We also find a flat-profile bar, in agreement with the strong bar, with the grand design spiral pattern, and with the gap between the ends of the bar and the start of the spiral arms. We quantify the rate of massive star formation, which is concentrated in the two spiral arms.

Erroz-Ferrer, Santiago; Font, Joan; Beckman, John E; Falcón-Barroso, Jesús; Sánchez-Gallego, José Ramón; Athanassoula, E; Bosma, Albert; Gadotti, Dimitri A; Muñoz-Mateos, Juan Carlos; Sheth, Kartik; Buta, Ronald J; Comerón, Sébastien; de Paz, Armando Gil; Hinz, Joannah L; Ho, Luis C; Kim, Taehyun; Laine, Jarkko; Laurikainen, Eija; Madore, Barry F; Menéndez-Delmestre, Karín; Mizusawa, Trisha; Regan, Michael W; Salo, Heikki; Seibert, Mark

2012-01-01

 
 
 
 
121

Galaxies with Background QSOs, I: A Search for Strong Galactic H-alpha Lines  

CERN Document Server

A search for emission lines in foreground galaxies in quasar spectra (z(gal) < z(QSO)) of the Sloan Digital Sky Survey (SDSS) data release 5 (DR5) reveals 23 examples of quasars shining through low redshift, foreground galaxies at small impact parameters (< 10 kpc). About 74,000 quasar spectra were examined by searching for narrow H{\\alpha} emission lines at z < 0.38, at a flux level greater than 5 \\times 10^-17 ergs cm^-2 s^-1, then confirming that other expected emission lines of the H II regions in the galaxy are detected. The galaxies were deblended from the quasar images to get colors and morphologies. For cases that allow the galaxy and the quasar to be deblended, the galaxies are blue (0.95 <(u-r)< 1.95). Extinction and reddening through the galaxies is determined from the (g-i) color excesses of the quasars. These reddening values are compared with the flux ratio of H{\\alpha} to H{\\beta}, which reflect the extinction for an undetermined fraction of the sightline through each galaxy. No ...

York, Donald G; Bishof, Michael; Kuttruff, Seth; Bowen, David; Kulkarni, Varsha P; Subbarao, Mark; Richards, Gordon; Berk, Daniel Vanden; Hall, Patrick B; Heckman, Timothy; Khare, Pushpa; Quashnock, Jean; Ghering, Lara; Johnson, Sean

2012-01-01

122

Shocks and Star Formation in Stephan's Quintet. I. Gemini Spectroscopy of H{\\alpha}-bright knots  

CERN Document Server

We present a Gemini-GMOS spectroscopic study of HST-selected H{\\alpha}-emitting regions in Stephan's Quintet (HCG 92), a nearby compact galaxy group, with the aim of disentangling the processes of shock-induced heating and star formation in its intra-group medium. The $\\approx$40 sources are distributed across the system, but most densely concentrated in the $\\sim$kpc-long shock region. Their spectra neatly divide them into narrow- and and broad-line emitters, and we decompose the latter into three or more emission peaks corresponding to spatial elements discernible in HST imaging. The emission line ratios of the two populations of H{\\alpha}-emitters confirm their nature as H II regions (90% of the sample) or molecular gas heated by a shock-front propagating at $\\lesssim$300 km/s. Their redshift distribution reveals interesting three-dimensional structure with respect to gas-phase baryons, with no H II regions associated with shocked gas, no shocked regions in the intruder galaxy NGC 7318B, and a sharp bounda...

Konstantopoulos, I S; Guillard, P; Trancho, G; Cluver, M E; Bastian, N; Charlton, J C; Fedotov, K; Gallagher, S C; Smith, L J; Struck, C J

2013-01-01

123

Equivalent widths for 6 RS CVn systems (Morel+, 2003)  

Science.gov (United States)

The spectra were acquired in January 2000 at the ESO 1.52-m telescope (La Silla, Chile) with the fiber-fed, cross-dispersed echelle spectrograph FEROS in the object+sky configuration. The atomic data have been calibrated using a high S/N moonlight spectrum extracted from the archive of the first FEROS commissioning period (fall 1998). (1 data file).

Morel, T.; Micela, G.; Favata, F.; Katz, D.; Pillitteri, I.

2003-11-01

124

FUNDPAR: A program for Deriving Fundamental Parameters from Equivalent Widths  

Directory of Open Access Journals (Sweden)

Full Text Available Implementamos un programa en Fortran que determina parámetros fundamentales de estrellas de tipo solar, a partir de anchos equivalentes del Fe. La solución debe verificar tres condiciones en el método estándar: equilibrio de ionización, equilibrio de excitación e independencia entre abundancias y anchos equivalentes. Calculamos modelos de atmósfera de Kurucz con opacidades NEWODF. Detalles como el parámetro de longitud de mezcla, el sobre impulso convectivo, etc. se calculan con un programa independiente. FUNDPAR calcula las incertezas por dos métodos: el criterio de Gonzalez & Vanture (1998 y utilizando la función ?² . Los resultados derivados con FUNDPAR están de acuerdo con determinaciones previas en la literatura. En particular obtuvimos parámetros fundamentales de 58 estrellas con exoplanetas. El programa está disponible en la red1.

C. Saffe

2011-01-01

125

O, B and Be stars equivalent widths (Lenorzer+, 2002)  

Science.gov (United States)

We present an atlas of spectra of O- and B-type stars, obtained with the Short Wavelength Spectrometer (SWS) during the Post-Helium program of the Infrared Space Observatory (ISO). This program is aimed at extending the Morgan & Keenan (1973ARA&A..11...29M) classification scheme into the near-infrared. Later type stars will be discussed in a separate publication. The observations consist of 57 SWS Post-Helium spectra from 2.4 to 4.1{mu}m, supplemented with 10 spectra acquired during the nominal mission with a similar observational setting. For B-type stars, this sample provides ample spectral coverage in terms of subtype and luminosity class. For O-type stars, the ISO sample is coarse and therefore is complemented with 8 UKIRT L'-band observations. In terms of the presence of diagnostic lines, the L'-band is likely the most promising of the near-infrared atmospheric windows for the study of the physical properties of B stars. Specifically, this wavelength interval contains the Br{alpha}, Pf{gamma}, and other Pfund lines which are probes of spectral type, luminosity class and mass loss. Here, we present simple empirical methods based on the lines present in the 2.4 to 4.1{mu}m interval that allow the determination of i) the spectral type of B dwarfs and giants to within two subtypes; ii) the luminosity class of B stars to within two classes; iii) the mass-loss rate of O stars and B supergiants to within 0.25dex. (4 data files).

Lenorzer, A.; Vandenbussche, B.; Morris, P.; de Koter, A.; Geballe, T.; Waters, L. B. F. M.; Hony, S.; Kaper, L.

2002-01-01

126

Equivalent widths of 9 stars of M 67 (Tautvaisiene+, 2000)  

Science.gov (United States)

High-resolution spectra of six core helium-burning `clump' stars and three giants in the open cluster M 67 have been obtained with the SOFIN spectrograph on the Nordic Optical Telescope to investigate abundances of up to 25 chemical elements. Abundances of carbon were studied using the C2 Swan (0,1) band head at 5635.5Å. The wavelength interval 7980-8130Å with strong CN features was analysed in order to determine nitrogen abundances and 12C/13C isotope ratios. The oxygen abundances were determined from the [O I] line at 6300Å. The overall metallicity of the cluster stars was found to be close to solar ([Fe/H]=-0.03+/-0.03). Compared with the Sun and other dwarf stars of the Galactic disk, as well as with dwarf stars of M 67 itself, abundances in the investigated stars suggest that carbon is depleted by about 0.2dex, nitrogen is enhanced by about 0.2dex and oxygen is unaltered. Among other mixing-sensitive chemical elements an overabundance of sodium may be suspected. The mean C/N and 12C/13C ratios are lowered to the values of 1.7+/-0.2 and 24+/-4 in the giants and to the values of 1.4+/-0.2 and 16+/-4 in the clump stars. These results suggest that extra mixing of CN-cycled material to the stellar surface takes place after the He-core flash. Abundances of heavy chemical elements in all nine stars were found to be almost identical and close to solar. (2 data files).

Tautvaisiene, G.; Edvardsson, B.; Tuominen, I.; Ilyin, I.

2000-08-01

127

Massive starburst galaxies in a z=2.16 proto-cluster unveiled by panoramic H-alpha mapping  

CERN Multimedia

We present a panoramic narrow-band study of H-alpha emitters in the field of the z=2.16 proto-cluster around PKS1138-262 using MOIRCS on the Subaru Telescope. We find 83 H-alpha emitters down to a SFR(Ha)~10Msun/yr across a ~7'x7' region centered on the radio galaxy, and identify ~10-Mpc scale filaments of emitters running across this region. By examining the properties of H-alpha emitters within the large-scale structure, we find that galaxies in the higher-density environments at z=2.16 tend to have redder colours and higher stellar masses compared to galaxies in more underdense regions. We also find a population of H-alpha emitters with red colours ((J-Ks)>1), which are much more frequent in the denser environments and which have apparently very high stellar masses with M*>~10^11Msun, implying that these cluster galaxies have already formed a large part of their stellar mass before z~2. Spitzer Space Telescope 24-micron data suggests that many of these red H-alpha emitters are bright, dusty starbursts (rat...

Koyama, Yusei; Tadaki, Ken-ichi; Hayashi, Masao; Tanaka, Masayuki; Smail, Ian; Tanaka, Ichi; Kurk, Jaron

2012-01-01

128

H-alpha emitters in z~2 proto-clusters: evidence for faster evolution in dense environments  

CERN Multimedia

This is a study of H-alpha emitters in two dense galaxy proto-clusters surrounding radio galaxies at z~2. We show that the proto-cluster surrounding MRC 1138-262 contains 14+/-2 times more H-alpha candidates than the average field (9 sigma significance), and the z=2.35 radio galaxy 4C+10.48 is surrounded by 12+/-2 times more emitters than the field (5 sigma), so it is also likely to reside in a dense proto-cluster environment. We compared these H-alpha emitters, situated in dense environments, to a control field sample selected from 3 separate fields forming a total area of 172 arcmin^2. We constructed and compared H-alpha and rest-frame R continuum luminosity functions of the emitters in both environments. The star formation density is on average 13 times greater in the proto-clusters than the field at z~2, so the total star formation rate within the central 1.5Mpc of the proto-clusters exceeds 3000Msun/yr. However, we found no significant difference in the shape of the H-alpha luminosity functions, implying...

Hatch, N A; Pentericci, L; Venemans, B P; Kuiper, E; Miley, G K; Röttgering, H J A

2011-01-01

129

Chromospheric Sunspot Oscillations in H-alpha and Ca II 8542A  

CERN Document Server

We study chromospheric oscillations including umbral flashes and running penumbral waves in a sunspot of active region (AR) using scanning spectroscopy in H-alpha and Ca II 8542A, with the Fast Imaging Solar Spectrograph (FISS) at the 1.6 meter New Solar Telescope at Big Bear Solar Observatory. A bisector method is applied to spectral observations to construct chromospheric Doppler velocity maps. Temporal sequence analysis of these shows enhanced high-frequency oscillations inside the sunspot umbra in both lines. Their peak frequency gradually decreases outward from the umbra. The oscillation power is found to be associated with magnetic-field strength and inclination, with different relationships in different frequency bands.

Maurya, Ram Ajor; Park, Hyungmin; Yang, Heesu; Song, Donguk; Cho, Kyuhyoun

2013-01-01

130

Five WC9 stars discovered in the AAO/UKST H-alpha Survey  

CERN Document Server

We report the discovery of 5 massive Wolf-Rayet (WR) stars resulting from a programme of follow-up spectroscopy of candidate emission line stars in the AAO/UKST Southern Galactic Plane H-alpha survey. The 6195-6775 angstrom spectra of the stars are presented and discussed. A WC9 class is assigned to all 5 stars through comparison of their spectra with those of known late-type WC stars, bringing the known total number of Galactic WC9 stars to 44. Whilst three of the five WC9 stars exhibit near infrared (NIR) excesses characteristic of hot dust emission -- as seen in the great majority of known WC9 stars -- we find that two of the stars show no discernible evidence of such excesses. This increases the number of known WC9 stars without NIR excesses to 7. Reddenings and distances for all 5 stars are estimated.

Hopewell, E C; Drew, J E; Unruh, Y C; Parker, Q A; Pierce, M J; Crowther, P A; Knigge, C; Phillipps, S; Zijlstra, A A

2005-01-01

131

The L-alpha/H-alpha intensity ratio in PKS 0237-23. [quasar  

Science.gov (United States)

The ratio I(L-alpha)/I(H-alpha) has been measured to be 1.7 plus or minus 0.6 in the quasar PKS 0237-23. The measured ratio is similar to that measured in 3C 273 by Davidsen et al. and to that inferred by Baldwin from a study of a large number of quasars; it is a factor of 5 to 14 smaller than expected from recombination theory. If the L-alpha radiation is resonantly scattered and there are modest amounts of dust within the ionized region, the measured ratio may be interpreted in terms of recombination theory, with L-alpha being depleted by absorption by the dust.

Hyland, A. R.; Becklin, E. E.; Neugebauer, G.

1978-01-01

132

Prominence and Cool Loop Energetics Measured in the UV, EUV, and H-alpha  

Science.gov (United States)

We investigate the thermal and dynamic properties of moving features in a prominence jet, a approx. 10(exp 5)K loop near a prominence channel, and an erupting prominence. In order to make measurements of the quickly moving features seen in prominences in the UV we use the SOHO/SUMER spectrograph to take a time series of exposures from a single pointing position, providing a measurement of spectral line properties as a function of time and position along the slit. The lines observed cover a broad range of temperatures from 80,000 - 1.6 million K. These measurements are combined with TRACE movies in transition region and coronal temperature bands and with ground based H-alpha data to obtain more complete information concerning prominence structure and motions. The resulting observations allow us perform DEM analysis and to calculate limits on densities, pressures, and the thermal and kinetic energies of the moving sources.

Kucera, Therese A.; Landi, E.

2006-01-01

133

High Resolution H alpha Images of the Binary Low-mass Proplyd LV 1 with the Magellan AO System  

CERN Document Server

We utilize the new Magellan adaptive optics system (MagAO) to image the binary proplyd LV 1 in the Orion Trapezium at H alpha. This is among the first AO results in visible wavelengths. The H alpha image clearly shows the ionization fronts, the interproplyd shell, and the cometary tails. Our astrometric measurements find no significant relative motion between components over ~18 yr, implying that LV 1 is a low-mass system. We also analyze Large Binocular Telescope AO observations, and find a point source which may be the embedded protostar's photosphere in the continuum. Converting the H magnitudes to mass, we show that the LV 1 binary may consist of one very-low-mass star with a likely brown dwarf secondary, or even plausibly a double brown dwarf. Finally, the magnetopause of the minor proplyd is estimated to have a radius of 110 AU, consistent with the location of the bow shock seen in H alpha.

Wu, Y -L; Males, J R; Follette, K; Morzinski, K; Kopon, D; Rodigas, T J; Hinz, P; Puglisi, A; Esposito, S; Pinna, E; Riccardi, A; Xompero, M; Briguglio, R

2013-01-01

134

Optical observations of the nearby galaxy IC342 with narrow band [SII] and H$\\alpha$ filters. I  

CERN Document Server

We present observations of the portion of the nearby spiral galaxy IC342 using narrow band [SII] and H$\\alpha$ filters. These observations were carried out in November 2011 with the 2m RCC telescope at Rozhen National Astronomical Observatory in Bulgaria. In this paper we report coordinates, diameters, H$\\alpha$ and [SII] fluxes for 203 HII regions detected in two fields of view in IC342 galaxy. The number of detected HII regions is 2.5 times higher than previously known in these two parts of the galaxy.

Vucetic, M M; Urosevic, D; Dobardzic, A; Pavlovic, M Z; Pannuti, T G; Petrov, N

2013-01-01

135

LIRIS multi-slit H_alpha spectroscopy of a z ~ 1 DEEP2 sample of star-forming galaxies  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present preliminary results of H_alpha near-infrared spectroscopy of six galaxies with redshifts z ~ 1 drawn from the DEEP2 Galaxy Redshift Survey. The spectra have been taken with the multi-slit mode of LIRIS (Long-slit Intermediate Resolution Infrared Spectrograph) installed at the 4.2-m William Herschel Telescope. This is a pilot study for a larger program to obtain H_alpha luminosities of about 50 star-forming galaxies at z ~ 1, with the aim of deriving the correspond...

Rodriguez-eugenio, Nayra; Noeske, Kai G.; Acosta-pulido, Jose; Barrena, Rafael; Prada, Francisco; Manchado, Arturo; Teams, Egs

2006-01-01

136

Graphs of Small Rank-width are Pivot-minors of Graphs of Small Tree-width  

CERN Multimedia

We prove that every graph of rank-width $k$ is a pivot-minor of a graph of tree-width at most $2k$. We also prove that graphs of rank-width at most 1, equivalently distance-hereditary graphs, are exactly vertex-minors of trees, and graphs of linear rank-width at most 1 are precisely vertex-minors of paths. In addition, we show that bipartite graphs of rank-width at most 1 are exactly pivot-minors of trees and bipartite graphs of linear rank-width at most 1 are precisely pivot-minors of paths.

Kwon, O-joung

2012-01-01

137

Nature of H-alpha selected galaxies at z>2. I. Main sequence and dusty star-forming galaxies  

CERN Document Server

We present the results from our narrow-band imaging surveys of HAEs at z=2.2 and z=2.5 in the Subaru/XMM-Newton Deep survey Field with near-infrared camera MOIRCS on Subaru Telescope. We have constructed a clean sample of 63 star-forming galaxies at z=2.2 and 46 at z=2.5. For 12 (or ~92%) out of 13 H\\alpha emitters (HAEs) at z=2.2, their H\\alpha emission lines have been successfully detected by the spectroscopy. While about 42% of the red, massive HAEs with M_*>10^{10.8} M_\\odot contain AGNs, most of the blue, less massive ones are likely to be star-forming galaxies. This suggests that the AGN may play an important role in galaxy evolution at the late stage of truncation. For the HAEs excluding possible AGNs, we estimate the gas-phase metallicities on the basis of [N~{\\sc ii}]/H\\alpha ratios, and find that the metallicities of the H\\alpha selected galaxies at z=2.2 are lower than those of local star-forming galaxies at fixed stellar mass, as shown by previous studies. Moreover, we present and discuss the so-c...

Tadaki, Ken-ichi; Tanaka, Ichi; Hayashi, Masao; Koyama, Yusei; Shimakawa, Rhythm

2013-01-01

138

H$\\alpha$ spectroscopy and multi-wavelength imaging of a solar flare caused by filament eruption  

CERN Multimedia

We study a sequence of eruptive events including filament eruption, a GOES C4.3 flare and a coronal mass ejection. We aim to identify the possible trigger(s) and precursor(s) of the filament destabilisation; investigate flare kernel characteristics; flare ribbons/kernels formation and evolution; study the interrelation of the filament-eruption/flare/coronal-mass-ejection phenomena as part of the integral active-region magnetic field configuration; determine H alpha line profile evolution during the eruptive phenomena. Multi-instrument observations are analysed including H$\\alpha$ line profiles, speckle images at H$\\alpha$-0.8 \\AA\\ and H$\\alpha$+0.8 \\AA\\ from IBIS at DST/NSO, EUV images and magnetograms from the SDO, coronagraph images from STEREO and the X-ray flux observations from FERMI and GOES. We establish that the filament destabilisation and eruption are the main trigger for the flaring activity. A surge-like event with a circular ribbon in one of the filament footpoints is determined as the possible t...

Huang, Z; Koleva, K; Doyle, J G; Duchlev, P; Dechev, M; Reardon, K

2014-01-01

139

Detection of H-alpha emission from z>3.5 submillimetre luminous galaxies with AKARI-FUHYU spectroscopy  

CERN Document Server

We present tentative H-alpha emission line detections of four submillimetre-detected galaxies at z>3.5: the radio galaxies 8C1909+722 and 4C60.07 at signal-to-noise ratios (SNRs) of 3.1 and 2.5, and two submillimetre-selected galaxies (SMGs) near the first of these at SNRs of 10.0 and 2.4, made with the AKARI Space Telescope as part of the FUHYU mission program. These are the highest-redshift H-alpha detections in such galaxies, made possible by AKARI's unique near-infrared spectroscopic capability. The two radio galaxies had known redshifts and surrounding structure, and we have detected broad H-alpha components indicating the presence of dust-shrouded quasars. We conclude that powerful AGNs at z>3.5 occur in peaks of the star-formation density fields, supporting a close connection between stellar mass build-up and black hole mass assembly at this redshift. We also show that 4C60.07 is a binary AGN. The H-alpha detections of the two SMGs are the first redshift determinations for these sources, confirming the...

Sedgwick, Chris; Pearson, Chris; Smail, Ian; Im, Myungshin; Oyabu, Shinki; Takagi, Toshinobu; Matsuhara, Hideo; Wada, Takehiko; Lee, Hyung Mok; Jeong, Woong-Seob; White, Glenn J

2013-01-01

140

Development of a high-speed H-alpha camera system for the observation of rapid fluctuations in solar flares  

Science.gov (United States)

A solid-state digital camera was developed for obtaining H alpha images of solar flares with 0.1 s time resolution. Beginning in the summer of 1988, this system will be operated in conjunction with SMM's hard X-ray burst spectrometer (HXRBS). Important electron time-of-flight effects that are crucial for determining the flare energy release processes should be detectable with these combined H alpha and hard X-ray observations. Charge-injection device (CID) cameras provide 128 x 128 pixel images simultaneously in the H alpha blue wing, line center, and red wing, or other wavelength of interest. The data recording system employs a microprocessor-controlled, electronic interface between each camera and a digital processor board that encodes the data into a serial bitstream for continuous recording by a standard video cassette recorder. Only a small fraction of the data will be permanently archived through utilization of a direct memory access interface onto a VAX-750 computer. In addition to correlations with hard X-ray data, observations from the high speed H alpha camera will also be correlated and optical and microwave data and data from future MAX 1991 campaigns. Whether the recorded optical flashes are simultaneous with X-ray peaks to within 0.1 s, are delayed by tenths of seconds or are even undetectable, the results will have implications on the validity of both thermal and nonthermal models of hard X-ray production.

Kiplinger, Alan L.; Dennis, Brian R.; Orwig, Larry E.; Chen, P. C.

1988-01-01

 
 
 
 
141

Development of a high-speed H-alpha camera system for the observation of rapid fluctuations in solar flares  

International Nuclear Information System (INIS)

A solid-state digital camera was developed for obtaining H alpha images of solar flares with 0.1 s time resolution. Beginning in the summer of 1988, this system will be operated in conjunction with SMM's hard X-ray burst spectrometer (HXRBS). Important electron time-of-flight effects that are crucial for determining the flare energy release processes should be detectable with these combined H alpha and hard X-ray observations. Charge-injection device (CID) cameras provide 128 x 128 pixel images simultaneously in the H alpha blue wing, line center, and red wing, or other wavelength of interest. The data recording system employs a microprocessor-controlled, electronic interface between each camera and a digital processor board that encodes the data into a serial bitstream for continuous recording by a standard video cassette recorder. Only a small fraction of the data will be permanently archived through utilization of a direct memory access interface onto a VAX-750 computer. In addition to correlations with hard X-ray data, observations from the high speed H alpha camera will also be correlated and optical and microwave data and data from future MAX 1991 campaigns. Whether the recorded optical flashes are simultaneous with X-ray peaks to within 0.1 s, are delayed by tenths of seconds or are even undetectable, the results will have implications on the validity of both thermal and nonthermal models of hard X-ray production

1988-11-01

142

An Atlas of H-alpha and R Images and Radial Profiles of 29 Bright Isolated Spiral Galaxies  

CERN Document Server

Narrow-band H-alpha+[NII] and broadband R images and surface photometry are presented for a sample of 29 bright (M_B < -18) isolated S0-Scd galaxies within a distance of 48 Mpc. These galaxies are among the most isolated nearby spiral galaxies of their Hubble classifications as determined from the Nearby Galaxies Catalog (Tully 1987a).

Koopmann, R A

2005-01-01

143

Discovery of H-alpha Emission from the Close Companion Inside the Gap of Transitional Disk HD142527  

CERN Document Server

We utilized the new high-order 585 actuator Magellan Adaptive Optics system (MagAO) to obtain very high-resolution visible light images of HD142527 with MagAO's VisAO science camera. In the median seeing conditions of the 6.5m Magellan telescope (0.5-0.7"), we find MagAO delivers 24-19% Strehl at H-alpha (0.656 microns). We detect a faint companion (HD142527B) embedded in this young transitional disk system at just 86.3+/-1.9 mas (~12 AU) from the star. The companion is detected in both H-alpha and a continuum filter (Delta_mag=6.33+/-0.20 mag at H-alpha and 7.50+/-0.25 mag in the continuum filter). This provides confirmation of the tentative companion discovered by Biller and co-workers with sparse aperture masking at the 8m VLT. The H-alpha emission from the ~0.25 solar mass companion (EW=180 Angstroms) implies a mass accretion rate of ~5.9x10^-10 Msun/yr, and a total accretion luminosity of 1.2% Lsun. Assuming a similar accretion rate, we estimate that a 1 Jupiter mass gas giant could have considerably bet...

Close, L M; Males, J R; Puglisi, A; Xompero, M; Apai, D; Najita, J; Weinberger, A J; Morzinski, K; Rodigas, T J; Hinz, P; Bailey, V; Briguglio, R

2014-01-01

144

H-alpha survey of low-mass satellites of the neighbouring galaxies M31 and M81  

CERN Document Server

Images have been obtained at the 6-m telescope at the Special Astrophysical Observatory (SAO) of the Russian Academy of Sciences in the H-alpha line and in the continuum for 20 dwarf spheroidal satellites of M31: And XI-And XXX, plus the distant Globular cluster Bol 520. Their star formation rates (FR) are estimated using the H-alpha flux and the ultraviolet FUV flux measured with the GALEX space telescope. Most of the dSph satellites of M31 have extremely low star formation rates with a characteristic upper limit of SFR~5x10^{-7}. We have made similar estimates of SFR from the H-alpha and FUV fluxes for 13 galaxies with low surface brightness recently discovered in the neighborhood of M81. Eleven of them are physical satellites of M81 with typical SFR< 5x10^{-5}. The median stellar masses of these satellites of M31 and M81 are 0.9 and 1.9 million solar masses, respectively. Our H-alpha observations place a 2-3 times stricter limit on the value of SFR than the data from the GALEX satellite, with a substant...

Kaisin, S S

2013-01-01

145

Photometry of HD 50064 - A Be supergiant star with a P Cygni profile at H-alpha  

International Nuclear Information System (INIS)

Photometric and spectroscopic observations of the B1 Ia star HD 50064 (NGC 2301 No. 3) are presented. It is found to be irregularly variable and to possess a P Cygni profile at H-alpha. It is found that the star is probably not an actual cluster member. 19 refs

1990-01-01

146

High speed imaging system in continuum and H-alpha at the Hida observatory for the study of high energy particles in solar flares  

Science.gov (United States)

Non-thermal particles are the fundamental ingredient of solar flares that carry the bulk energy released from the coronal magnetic fields and cause subsequent heating of the solar atmosphere to produce the radiation of wide range of electro-magnetic waves. The observations of hard X-ray and radio emissions suggest a rapid change of population of high energy particles with a time scale of sub-second. Flare kernels observed in visible lights, ex., H-alpha and continuum, show drastic evolutions in space and time during the rising phase of solar flares, and thought to be representing the locations of the precipitation of high energy particles into the chromosphere. Therefore the observations of flare kernels with high spatial and temporal resolutions provide valuable diagnosis of the distribution of high energy particles together with the information of connectivity of coronal magnetic fields. We developed a new high speed imaging system on a 25cm diameter telescope of the Solar Magnetic Activity Research Telescope (SMART) at the Hida observatory of Kyoto University. Images in H-alpha (width~3A) and continuum (6547A, width~10A) are recorded simultaneously with two CCD cameras with a spatial sampling of 0.2 arcsec/pix, field coverage of 344 arcsec x 258 arcsec, and a frame rate of 30fr/sec. Observation is conducted continuously by focusing a targeted active region every day, while only data sets that capture flare events are permanently stored for further analysis. The spatial and temporal evolutions of flare kernels thus obtained are combined with photospheric vector magnetic field taken by the SMART, SOT/Hinode and HMI/SDO, radio data by NoRH, hard X-ray image by RHESSI, and X-ray / UV images by SXT/Hinode and AIA/SDO to identify the instantaneous locations of high energy particles injection in the corona. In this paper we will present an overview of the observing system and its initial results. This work was carried out by the joint research program of the Solar-Terrestorial Environment Laboratory, Nagoya University.

Ichimoto, K.; Kawate, T.; Yoshikazu, N.; Ishii, T.; Nagata, S.; Asai, A.; Masuda, S.; Kusano, K.; Yamamoto, T. T.; Minoshima, T.; Yokoyama, T.; Watanabe, K.

2011-12-01

147

The Tremaine-Weinberg method for pattern speeds using H-alpha emission from ionized gas  

CERN Document Server

The Fabry-Perot interferometer FaNTOmM was used at the 3.6m Canada France Hawaii Telescope and the 1.6m Mont Megantic Telescope to obtain data cubes in H-alpha of 9 nearby spiral galaxies from which maps in integrated intensity, velocity, and velocity dispersion were derived. We then applied the Tremaine-Weinberg method, in which the pattern speed can be deduced from its velocity field, by finding the integrated value of the mean velocity along a slit parallel to the major axis weighted by the intensity and divided by the weighted mean distance of the velocity points from the tangent point measured along the slit. The measured variables can be used either to make separate calculations of the pattern speed and derive a mean, or in a plot of one against the other for all the points on all slits, from which a best fit value can be derived. Linear fits were found for all the galaxies in the sample. For two galaxies a clearly separate inner pattern speed with a higher value, was also identified and measured.

Beckman, John E; Piñol, Núria; Toonen, Silvia; Hernandez, Olivier; Carignan, Claude

2007-01-01

148

GH $\\alpha$ FaS : Galaxy H-alpha Fabry-Perot System for the WHT  

CERN Multimedia

GH$\\alpha$FaS a new Fabry-Perot system, is now available at the William Herschel Telescope. It was mounted, for the first time, at the Nasmyth focus of the 4.2 meter WHT on La Palma in July 2007. Using modern technology, with a spectral resolution of the order R$\\sim$15000, and with a seeing limited spatial resolution, GH$\\alpha$FaS will provide a new look at the H$\\alpha$ -emitting gas over a 4.8 arcminutes circular field in the nearby universe. Many science programs can be done on a 4.2 metre class telescope in world class seeing conditions with a scanning Fabry-Perot. Not only galaxies but HII regions, planetary nebulae, supernova remnants and the diffuse interstellar medium are subjects for which unique data can be aquired rapidly. Astronomers from the Laboratoire d'Astrophysique Exp\\'erimentale (LAE) in Montr\\'eal, the Laboratoire d'Astrophysique de Marseille (LAM-OAMP), and the Instituto de Astrof\\'isica de Canarias (IAC), have inaugurated GH$\\alpha$FaS by studying in detail the dynamics of some nearby ...

Hernández, O; Carignan, C; Beckman, J; Gach, J L; Balard, P; Amram, P; Boulesteix, J; Corradi, R L M; de Denus-Baillargeon, M-M; Epinat, B; Relaño, M; Thibault, S; Vallée, P

2008-01-01

149

H-alpha Kinematics of the SINGS Nearby Galaxies Survey. II  

CERN Multimedia

This is the second part of an H-alpha kinematics follow-up survey of the Spitzer Infrared Nearby Galaxies Survey (SINGS) sample. The aim of this program is to shed new light on the role of baryons and their kinematics and on the dark/luminous matter relation in the star forming regions of galaxies, in relation with studies at other wavelengths. The data for 37 galaxies are presented. The observations were made using Fabry-Perot interferometry with the photon-counting camera FaNTOmM on 4 different telescopes, namely the Canada-France-Hawaii 3.6m, the ESO La Silla 3.6m, the William Herschel 4.2m, and the Observatoire du mont Megantic 1.6m telescopes. The velocity fields are computed using custom IDL routines designed for an optimal use of the data. The kinematical parameters and rotation curves are derived using the GIPSY software. It is shown that non-circular motions associated with galactic bars affect the kinematical parameters fitting and the velocity gradient of the rotation curves. This leads to incorrec...

Dicaire, I; Amram, P; Hernández, O; Chemin, L; Daigle, O; de Denus-Baillargeon, M -M; Balkowski, C; Boselli, A; Fathi, K; Kennicutt, R C

2008-01-01

150

The H$\\alpha$ kinematics of interacting galaxies in 12 compact groups  

CERN Document Server

We present new Fabry-Perot observations for a sample of 42 galaxies located in twelve compact groups of galaxies: HCG 1, HCG 14, HCG 25, HCG 44, HCG 53, HCG 57, HCG 61, HCG 69, HCG 93, VV 304, LGG 455 and Arp 314. From the 42 observed galaxies, a total of 26 objects are spiral galaxies, which range from Sa to Im morphological types. The remaining 16 objects are E, S0 and S0a galaxies. Using these observations, we have derived velocity maps, monochromatic and velocity dispersion maps for 24 galaxies, where 18 are spiral, three are S0a, two are S0 and one is an Im galaxy. From the 24 velocity fields obtained, we could derive rotation curves for 15 galaxies; only two of them exhibit rotation curves without any clear signature of interactions. Based on kinematic information, we have evaluated the evolutionary stage of the different groups of the current sample. We identify groups that range from having no H$\\alpha$ emission to displaying an extremely complex kinematics, where their members display strongly pertur...

Torres-Flores, S; de Oliveira, C Mendes; Plana, H; Balkowski, C; Marcelin, M; Olave-Rojas, D

2014-01-01

151

A census of H$\\alpha$ emitters in the intergalactic medium of the NGC 2865 system  

CERN Document Server

Tidal debris which are rich in HI gas, formed in interacting and merging systems, are suitable laboratories to study star formation outside galaxies. Recently, several such systems were observed, which contained many young star forming regions outside the galaxies. In previous works, we have studied young star forming regions outside galaxies in different systems with optical and/or gaseous tidal debris, all of them with available archive GALEX/UV images, in order to understand how often they occur and in which type of environments. In this paper we searched for star forming regions around the galaxy NGC2865, a shell galaxy which is circled by a ring of HI, with a total mass of 1.2 x 10$^9$ M$_\\odot$. Using the Multi-Slit Imaging Spectroscopy Technique with the Gemini telescope, we detected all H$\\alpha$ emitting sources in the surroundings of the galaxy NGC2865, down to a flux limit of 10$^{-18}$ erg cm$^{-2}$ s$^{-1}$ \\AA$^{-1}$. Together with Near and Far-Ultraviolet flux information we characterize the st...

Urrutia-Viscarra, F; de Oliveira, C Mendes; Gerhard, O; Torres-Flores, S; Carrasco, E R; de Mello, D

2014-01-01

152

The KPNO International Spectroscopic Survey. IV. H-alpha-selected Survey List 2  

CERN Multimedia

The KPNO International Spectroscopic Survey (KISS) is an objective-prism survey for extragalactic emission-line objects. It combines many of the features of previous slitless spectroscopic surveys with the advantages of modern CCD detectors, and is the first purely digital objective-prism survey for emission-line galaxies. Here we present the second list of emission-line galaxy candidates selected from our red spectral data, which cover the wavelength range 6400 to 7200 A. In most cases, the detected emission line is H-alpha. The current survey list covers a 1.6-degree-wide strip located at Dec(1950) = 43d 30' and spans the RA range 11h 55m to 16h 15m. The survey strip runs through the center of the Bootes Void, and has enough depth to adequately sample the far side of the void. An area of 65.8 sq. deg. is covered. A total of 1029 candidate emission-line objects have been selected for inclusion in the survey list (15.6 per sq. deg.). We tabulate accurate coordinates and photometry for each source, as well as ...

Gronwall, C; Sarajedini, V L; Jangren, A; Chomiuk, L; Moody, J; Frattare, L; Boroson, T A

2004-01-01

153

Estimation of {sup 3}J{sub HN-H{alpha}} and {sup 3}J{sub H}{alpha}{sub -H{beta}} coupling constants from heteronuclear TOCSY spectra  

Energy Technology Data Exchange (ETDEWEB)

{sup 3}J proton-proton coupling constants bear information on the intervening dihedral angles. Methods have been developed to derive this information from NMR spectra of proteins. Using series expansion of the time dependent density matrix, and exploiting the simple topology of amino acid spin-systems, formulae for estimation of {sup 3}J{sub HN-H{alpha}} and {sup 3}J{sub H}{alpha}{sub -H{beta}} from HSQC-TOCSY spectra are derived. The results obtained on a protein entailing both {alpha}-helix and {beta}-sheet secondary structure elements agree very well with J-coupling constants computed from the X-ray structure. The method compares well with existing methods and requires only 2D spectra which would be typically otherwise recorded for structural studies.

Pagano, Katiuscia; Fogolari, Federico, E-mail: ffogolari@mail.dstb.uniud.it; Corazza, Alessandra; Viglino, Paolo; Esposito, Gennaro [Universita di Udine, Dipartimento di Scienze e Tecnologie Biomediche (Italy)

2007-11-15

154

Resonances and resonance widths  

Energy Technology Data Exchange (ETDEWEB)

Two-dimensional betatron resonances are much more important than their simple one-dimensional counterparts and exhibit a strong dependence on the betatron phase advance per cell. A practical definition of ''width'' is expanded upon in order to display these relations in tables. A primarily pedagogical introduction is given to explain the tables, and also to encourage a wider capability for deriving resonance behavior and wider use of ''designer'' resonances.

Collins, T.

1986-05-01

155

Narrow width pentaquarks  

CERN Multimedia

A general study of pentaquarks built with four quarks in a L=1 state and an antiquark in S-wave shows that several of such states are forbidden by a selection rule, which holds in the limit of flavour symmetry, to decay into a baryon and a meson final state. We identify the most promising \\bar{10} multiplet for the classification of the Theta^+ and Xi^{--} particles recently discovered with the prediction of a narrow width for both of them.

Buccella, F

2004-01-01

156

Resonances and resonance widths  

International Nuclear Information System (INIS)

Two-dimensional betatron resonances are much more important than their simple one-dimensional counterparts and exhibit a strong dependence on the betatron phase advance per cell. A practical definition of ''width'' is expanded upon in order to display these relations in tables. A primarily pedagogical introduction is given to explain the tables, and also to encourage a wider capability for deriving resonance behavior and wider use of ''designer'' resonances

1986-01-01

157

Newly Discovered Cataclysmic Variables from the INT/WFC Photometric H alpha Survey of the Northern Galactic Plane  

CERN Multimedia

We report the discovery of 11 new cataclysmic variable (CV) candidates by the Isaac Newton Telescope (INT) Photometric H alpha Survey of the northern Galactic plane (IPHAS). Three of the systems have been the subject of further follow-up observations. For the CV candidates IPHAS J013031.90+622132.4 and IPHAS J051814.34+294113.2, time-resolved optical spectroscopy has been obtained and radial-velocity measurements of the H alpha emission-line have been used to estimate their orbital periods. A third CV candidate (IPHAS J062746.41+ 014811.3) was observed photometrically and found to be eclipsing. All three systems have orbital periods above the CV period-gap of 2-3 h. We also highlight one other system, IPHAS J025827.88+635234.9, whose spectrum distinguishes it as a likely high luminosity object with unusual C and N abundances.

Witham, A R; Aungwerojwit, A; Drew, J E; Gänsicke, B T; Greimel, R; Groot, P J; Roelofs, G H A; Steeghs, D; Woudt, P A

2007-01-01

158

An Entropy Threshold for Strong H-alpha and Radio Emission in the Cores of Galaxy Clusters  

CERN Document Server

Our Chandra X-ray Observatory archival study of intracluster entropy in a sample of 222 galaxy clusters shows that H-alpha and radio emission from the brightest cluster galaxy are much more pronounced when the cluster's core gas entropy is < 30 keV cm^2. The prevalence of H-alpha emission below this threshold indicates that it marks a dichotomy between clusters that can harbor multiphase gas and star formation in their cores and those that cannot. The fact that strong central radio emission also appears below this boundary suggests that AGN feedback turns on when the intracluster medium starts to condense, strengthening the case for AGN feedback as the mechanism that limits star formation in the Universe's most luminous galaxies.

Cavagnolo, Kenneth W; Voit, G Mark; Sun, Ming

2008-01-01

159

A high-speed digital camera system for the observation of rapid H-alpha fluctuations in solar flares  

Science.gov (United States)

Researchers developed a prototype digital camera system for obtaining H-alpha images of solar flares with 0.1 s time resolution. They intend to operate this system in conjunction with SMM's Hard X Ray Burst Spectrometer, with x ray instruments which will be available on the Gamma Ray Observatory and eventually with the Gamma Ray Imaging Device (GRID), and with the High Resolution Gamma-Ray and Hard X Ray Spectrometer (HIREGS) which are being developed for the Max '91 program. The digital camera has recently proven to be successful as a one camera system operating in the blue wing of H-alpha during the first Max '91 campaign. Construction and procurement of a second and possibly a third camera for simultaneous observations at other wavelengths are underway as are analyses of the campaign data.

Kiplinger, Alan L.; Dennis, Brian R.; Orwig, Larry E.

1989-01-01

160

Nature of H-alpha selected galaxies at z>2. II. Clumpy galaxies and compact star-forming galaxies  

CERN Document Server

We present the morphological properties of 109 H\\alpha-selected galaxies at z>2 in SXDF-UDS-CANDELS field. With high-resolution optical/near-infrared images obtained by Hubble Space Telescope, we identify giant clumps within the H\\alpha emitters (HAEs). We find that at least 41% of our sample show clumpy structures in the underlying disks. The color gradient of clumps is commonly seen in the sense that the clumps near the galactic center tend to be redder than those in the outer regions. The mid-infrared detection in galaxies with red clumps and the spatial distribution of H\\alpha emission suggest that dusty star-formation activity is probably occurring in the nuclear red clumps. A gas supply to a bulge component through the clump migration is one of the most potent physical processes to produce such dusty star-forming clumps and form massive bulges in local early-type galaxies. They would become large quiescent galaxies at later times just by consumption or blowout of remaining gas. Also, while most of the H...

Tadaki, Ken-ichi; Tanaka, Ichi; Hayashi, Masao; Koyama, Yusei; Shimakawa, Rhythm

2013-01-01

 
 
 
 
161

Cosmic Star Formation Activity at z=2.2 Probed by H-alpha Emission Line Galaxies  

CERN Multimedia

We present a pilot narrow-band survey of H-alpha emitters at z=2.2 in the Great Observatories Origins Deep Survey North (GOODS-N) field with MOIRCS instrument on the Subaru telescope. The survey reached a 3 sigma limiting magnitude of 23.6 (NB209) which corresponds to a 3 sigma limiting line flux of 2.5 x 10^-17 erg s^-1 cm^-2 over a 56 arcmnin^2 contiguous area (excluding a shallower area). From this survey, we have identified 11 H-alpha emitters and one AGN at z=2.2 on the basis of narrow-band excesses and photometric redshifts. We obtained spectra for seven new objects among them, including one AGN, and an emission line above 3 sigma is detected from all of them. We have estimated star formation rates (SFR) and stellar masses (M_star) for individual galaxies. The average SFR and M_star is 27.8M_solar yr^-1 and 4.0 x 10^10M_solar, respectivly. Their specific star formation rates are inversely correlated with their stellar masses. Fitting to a Schechter function yields the H-alpha luminosity function with lo...

Tadaki, Ken-ichi; Koyama, Yusei; Hayashi, Masao; Tanaka, Ichi; Tokoku, Chihiro

2010-01-01

162

Evidence of Environmental Dependencies of Type Ia Supernovae from the Nearby Supernova Factory indicated by Local H{\\alpha}  

CERN Document Server

(Abridged) We study the host galaxy regions in close proximity to Type Ia supernovae (SNe Ia) to analyze relations between the properties of SN Ia events and environments most similar to where their progenitors formed. We focus on local H\\alpha\\ emission as an indicator of young environments. The Nearby Supernova Factory has obtained flux-calibrated spectral timeseries for SNe Ia using integral field spectroscopy, allowing the simultaneous measurement of the SN and its immediate vicinity. For 89 SNe Ia we measure H\\alpha\\ emission tracing ongoing star formation within a 1 kpc radius around each SN. This constitutes the first direct study of the local environment for a large sample of SNe Ia also having accurate luminosity, color and stretch measurements. We find that SNe Ia with local H\\alpha\\ emission are redder by 0.036+/-0.017 mag, and that the previously-noted correlation between stretch and host mass is entirely driven by the SNe Ia coming from passive regions. Most importantly, the mean standardized bri...

Rigault, M; Aldering, G; Antilogus, P; Aragon, C; Bailey, S; Baltay, C; Bongard, S; Buton, C; Canto, A; Cellier-Holzem, F; Childress, M; Chotard, N; Fakhouri, H K; Feindt, U; Fleury, M; Gangler, E; Greskovic, P; Guy, J; Kim, A G; Kowalski, M; Lombardo, S; Nordin, J; Nugent, P; Pain, R; Pécontal, E; Pereira, R; Perlmutter, S; Rabinowitz, D; Runge, K; Saunders, C; Scalzo, R; Smadja, G; Tao, C; Thomas, R C; Weaver, B A

2013-01-01

163

H-Alpha and Hard X-Ray Observations of a Two-Ribbon Flare Associated with a Filament Eruption  

CERN Multimedia

We perform a multi-wavelength study of a two-ribbon flare on 2002 September 29 and its associated filament eruption, observed simultaneously in the H-alpha line by a ground-based imaging spectrograph and in hard X-rays by RHESSI. The flare ribbons contain several H-alpha bright kernels that show different evolutional behaviors. In particular, we find two kernels that may be the footpoints of a loop. A single hard X-ray source appears to cover these two kernels and to move across the magnetic neutral line. We explain this as a result of the merging of two footpoint sources that show gradually asymmetric emission owing to an asymmetric magnetic topology of the newly reconnected loops. In one of the H-alpha kernels, we detect a continuum enhancement at the visible wavelength. By checking its spatial and temporal relationship with the hard X-ray emission, we ascribe it as being caused by electron beam precipitation. In addition, we derive the line-of-sight velocity of the filament plasma based on the Doppler shif...

Ding, M D; Li, J P; Chen, P F

2003-01-01

164

A comparison between Pa alpha and H alpha emission The relation between HII region reddening, local gas density and metallicity  

CERN Document Server

We measure reddenings to HII regions in NGC 2903, NGC 1512, M51, NGC 4449 and NGC 6946 from Hubble Space Telescope Pa alpha and H alpha images. Extinctions range from A_V ~ 5 - 0 depending upon the galaxy. For the galaxies with HST images in both lines, NGC 2903, NGC 1512 and M51, the Pa alpha and H alpha emission are almost identical in morphology which implies that little emission from bright HII regions is hidden from view by regions of comparatively high extinction. The scatter in the measured extinctions is only +- 0.5 mag. We compare the reddenings we measure in five galaxies using the Pa alpha to H alpha ratios to those measured previously from the Balmer decrement in the LMC and as a function of radius in M101 and M51. We find that luminosity weighted mean extinctions are correlated with gas surface density and metallicity. The correlation is consistent with the mean extinction depending on dust density where the dust to gas mass ratio scales with the metallicity. This trend is expected if HII regions...

Quillen, A C; Yukita, Mihoko

2001-01-01

165

The Second Data Release of the INT Photometric H\\alpha\\ Survey of the Northern Galactic Plane (IPHAS DR2)  

CERN Document Server

The INT/WFC Photometric H-Alpha Survey of the Northern Galactic Plane (IPHAS) is a 1800 square degrees imaging survey covering Galactic latitudes |b| < 5 deg and longitudes l = 30 to 215 deg in the r, i and H\\alpha\\ filters using the Wide Field Camera (WFC) on the 2.5-metre Isaac Newton Telescope (INT) in La Palma. We present the first quality-controlled and globally-calibrated source catalogue derived from the survey, providing single-epoch photometry for 219 million unique sources across 92% of the footprint. The observations were carried out between 2003 and 2012 at a median seeing of 1.1 arcsec (sampled at 0.33 arcsec/pixel) and to a mean 5\\sigma-depth of 21.2 (r), 20.0 (i) and 20.3 (H\\alpha) in the Vega magnitude system. We explain the data reduction and quality control procedures, describe and test the global re-calibration, and detail the construction of the new catalogue. We show that the new calibration is accurate to 0.03 mag (rms) and recommend a series of quality criteria to select the most rel...

Barentsen, Geert; Drew, J E; González-Solares, E A; Greimel, R; Irwin, M J; Miszalski, B; Ruhland, C; Groot, P; Mampaso, A; Sale, S E; Henden, A A; Aungwerojwit, A; Barlow, M J; Carter, P J; Corradi, R L M; Drake, J J; Eislöffel, J; Fabregat, J; Gänsicke, B T; Fusillo, N P Gentile; Greiss, S; Hales, A S; Hodgkin, S; Huckvale, L; Irwin, J; King, R; Knigge, C; Kupfer, T; Lagadec, E; Lennon, D J; Lewis, J R; Mohr-Smith, M; Morris, R A H; Naylor, T; Parker, Q A; Phillipps, S; Pyrzas, S; Raddi, R; Roelofs, G H A; Rodríguez-Gil, P; Sabin, L; Scaringi, S; Steeghs, D; Suso, J; Tata, R; Unruh, Y C; van Roestel, J; Viironen, K; Vink, J S; Walton, N A; Wright, N J; Zijlstra, A A

2014-01-01

166

Disparity between H\\alpha\\ and H\\beta\\ in SN 2008in: inhomogeneous external layers of type IIP supernovae?  

CERN Document Server

We study disparity between H\\alpha\\ and H\\beta\\ in early spectra of the type IIP supernova SN 2008in. The point is that these lines cannot be described simultaneously in a spherically-symmetric model with the smooth density distribution. It is shown that an assumption of a clumpy structure of external layers of the envelope resolves the problem. We obtain estimates of the velocity at the inner border of the inhomogeneous zone (\\approx6100 km s^{-1}), the filing factor of inhomogeneities (\\leq0.5), and the mass of the inhomogeneous layers (~ 0.03 M_{\\odot}). The amplitude of flux fluctuations in the early spectrum of H\\alpha\\ (\\Delta F/F ~ 10^{-2}) imposes a constraint on the size of inhomogeneities (\\leq 200 km s^{-1}). A detection of fluctuations in the early H\\alpha\\ of type IIP supernovae might become an observational test of the inhomogeneous structure of their envelopes. We propose also the indirect test of the clumpy structure of external layers: the study of properties of the initial radiation outburst...

Chugai, N N

2013-01-01

167

Stellar Populations and the Star Formation Histories of LSB Galaxies: I. Optical and H-alpha Imaging  

CERN Document Server

This paper presents optical and H-alpha imaging for a large sample of LSB galaxies selected from the PSS-II catalogs (Schombert et. al 1992). As noted in previous work, LSB galaxies span a range of luminosities (-10 > M_V > -20) and sizes (0.3 kpc < R_V25 < 10 kpc), although they are consistent in their irregular morphology. Their H-alpha luminosities (L(H-alpha) range from 10^36 to 10^41 ergs s^-1 (corresponding to a range in star formation, using canonical prescriptions, from 10^-5 to 1 M_solar yr^-1). Although their optical colors are at the extreme blue edge for galaxies, they are similar to the colors of dwarf galaxies (van Zee 2001) and gas-rich irregulars (Hunter & Elmegreen 2006). However, their star formation rates per unit stellar mass are a factor of ten less than other galaxies of the same baryonic mass, indicating that they are not simply quiescent versions of more active star forming galaxies. This paper presents the data, reduction techniques and new philosophy of data storage and pre...

Schombert, James; McGaugh, Stacy

2011-01-01

168

HIGH RESOLUTION H{alpha} IMAGES OF THE BINARY LOW-MASS PROPLYD LV 1 WITH THE MAGELLAN AO SYSTEM  

Energy Technology Data Exchange (ETDEWEB)

We utilize the new Magellan adaptive optics system (MagAO) to image the binary proplyd LV 1 in the Orion Trapezium at H{alpha}. This is among the first AO results in visible wavelengths. The H{alpha} image clearly shows the ionization fronts, the interproplyd shell, and the cometary tails. Our astrometric measurements find no significant relative motion between components over {approx}18 yr, implying that LV 1 is a low-mass system. We also analyze Large Binocular Telescope AO observations, and find a point source which may be the embedded protostar's photosphere in the continuum. Converting the H magnitudes to mass, we show that the LV 1 binary may consist of one very-low-mass star with a likely brown dwarf secondary, or even plausibly a double brown dwarf. Finally, the magnetopause of the minor proplyd is estimated to have a radius of 110 AU, consistent with the location of the bow shock seen in H{alpha}.

Wu, Y.-L.; Close, L. M.; Males, J. R.; Follette, K.; Morzinski, K.; Kopon, D.; Rodigas, T. J.; Hinz, P. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Puglisi, A.; Esposito, S.; Pinna, E.; Riccardi, A.; Xompero, M.; Briguglio, R., E-mail: yalinwu@email.arizona.edu [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy)

2013-09-01

169

Robust line width estimation  

Energy Technology Data Exchange (ETDEWEB)

Fabrication of diffused titanium optical guides on a LiNbO/sub 3/ crystal substrate requires precise quality assurance. Light couplers in particular must be positioned within micron specifications. This requirement is the reason that the width of lines detected during microscopic inspection of the crystal is such an important parameter for quality evaluation. To assist in the inspection of these optical guides, a line width estimation program has been developed for an IBM PC based microscope inspection system. A digital image processing approach is used to develop an algorithm which can be tailored by the user for specific signal and noise characteristics. Default filter parameters, which can be updated and saved interactively by the user, are stored in a file on disk. The final program can be executed stand-alone or through a commercially available, menu-driven, image processing software package. Details concerning the implementation of this program are presented in this report. These include instructions for using the program, a description of the voting approach to edge detection, and a discussion of the line fitting subroutine. 5 refs., 1 fig. (DWL)

Fitch, J.P.; Portnoff, M.R.

1986-07-01

170

Integral Field Spectroscopy based H\\alpha\\ sizes of local Luminous and Ultraluminous Infrared Galaxies. A Direct Comparison with high-z Massive Star Forming Galaxies  

CERN Multimedia

Aims. We study the analogy between local U/LIRGs and high-z massive SFGs by comparing basic H{\\alpha} structural characteristics, like size, luminosity and Star Formation Rate (SFR) surface density, in an homogeneous way (i.e. same tracer and size definition, similar physical scales). Methods. We use Integral Field Spectroscopy based H{\\alpha} emission maps for a representative sample of 54 local U/LIRGs (66 galaxies). From this initial sample we select 26 objects with H{\\alpha} luminosities (L(H{\\alpha})) similar to those of massive (i.e. M\\ast \\sim 10^10 M\\odot or larger) SFGs at z \\sim 2, and probing similar physical scales. Results. The sizes of the H{\\alpha} emitting region in the sample of local U/LIRGs span a large range, with r1/2(H{\\alpha}) from 0.2 to 7 kpc. However, about 2/3 of local U/LIRGs with Lir > 10^11.4 L\\odot have compact H{\\alpha} emission (i.e. r1/2 2 kpc). These are systems showing pre-coalescence merger activity and they are indistinguishable from the massive high-z SFGs galaxies in t...

Arribas, S; Alonso-Herrero, A; Rosales-Ortega, F F; Monreal-Ibero, A; García-Marín, M; García-Burillo, S; Rodríguez-Zaurín, J

2012-01-01

171

Sub-THz and H{\\alpha} activity during the preflare and main phases of a GOES class M2 event  

CERN Multimedia

Radio and optical observations of the evolution of flare-associated phenomena have shown an initial and rapid burst at 0.4 THz only followed subsequently by a localized chromospheric heating producing an H{\\alpha} brightening with later heating of the whole active region. A major instability occurred several minutes later producing one impulsive burst at microwaves only, associated with an M2.0 GOES X-ray flare that exhibited the main H{\\alpha} brightening at the same site as the first flash. The possible association between long-enduring time profiles at soft X-rays, microwaves, H{\\alpha} and sub-THz wavelengths is discussed. In the decay phase the H{\\alpha} movie shows a disrupting magnetic arch structure ejecting dark, presumably chromospheric, material upwards. The time sequence of events suggests genuine interdependent and possibly non-thermal instabilities triggering phenomena, with concurrent active region plasma heating and material ejection.

Kaufmann, Pierre; de Castro, C Guillermo Giménez; White, Stephen M; Raulin, Jean-Pierre; Correia, Emilia; Fernandes, Luis Olavo; de Souza, Rodney V; Godoy, Rodolfo; Marun, Adolfo; Pereyra, Pablo

2011-01-01

172

Alpha widths from nuclear models  

International Nuclear Information System (INIS)

Methods to calculate alpha widths from nuclear model wavefunctions are reviewed and the underlying assumptions discussed. Comparison of experimental and calculated reduced widths is made. Some new results on absolute values of alpha transition rates are reported

1975-04-21

173

Detailed correlation of type III radio bursts with H alpha activity. I - Active region of 22 May 1970.  

Science.gov (United States)

Comparison of observations of type III impulsive radio bursts made at the Clark Lake Radio Observatory with high-spatial-resolution cinematographic observations taken at the Big Bear Solar Observatory. Use of the log-periodic radio interferometer makes it possible to localize the radio emission uniquely. This study concentrates on the particularly active region close to the limb on May 22, 1970. Sixteen of the 17 groups were associated with some H alpha activity, 11 of them with the start of such activity.

Kuiper, T. B. H.; Pasachoff, J. M.

1973-01-01

174

Photometric H alpha and [O II] Luminosity Function of SDF and SXDF Galaxies: Implications for Future Baryon Oscillation Surveys  

CERN Multimedia

Efficient selection of emission line galaxies at z > 1 by photometric information in wide field surveys is one of the keys for future spectroscopic surveys to constrain dark energy using the baryon acoustic oscillation (BAO) signature. Here we estimate the H alpha and [O II] line luminosity functions of galaxies at z = 0.5-1.7 using a novel approach where multi-wavelength imaging data is used to jointly estimate both photometric redshifts and star-formation rates. These photometric estimates of line luminosities at high-redshift use the large data sets of the Subaru Deep Field and Subaru XMM-Newton Deep Field (covering \\sim 1 deg^2) and are calibrated with the spectroscopic data of the local Sloan Digital Sky Survey galaxies. The derived luminosity functions (especially H alpha) are in reasonable agreement with the past estimates based on spectroscopic or narrow-band-filter surveys. This dataset is useful for examining the photometric selection of target galaxies for BAO surveys because of the large cosmologi...

Sumiyoshi, Masanao; Oshige, Shunsuke; Glazebrook, Karl; Akiyama, Masayuki; Morokuma, Tomoki; Motohara, Kentaro; Shimasaku, Kazuhiro; Hayashi, Masao; Yoshida, Makiko; Kashikawa, Nobunari; Kodama, Tadayuki

2009-01-01

175

CO Observations of a FeLoBAL Quasar with an H alpha Absorption Line at z=2.3  

CERN Document Server

SDSS J083942.11+380526.3 is an Iron Low-ionization Broad Absorption Line (FeLoBAL) quasar at z = 2.3, and Aoki et al. (2006) recently found the presence of an H alpha absorption line in the broad H alpha emission line. Motivated by an idea that this quasar may be a huge molecular gas reservoir in the early phase of quasar evolution, we made CO(J=3-2) observations of it using the Nobeyama Millimeter Array. No significant CO emission was detected; although an emission-like feature (2.5 sigma) was seen close (~ 2") to the quasar, we regard it as a noise. The obtained 3 sigma upper limit on the CO luminosity is L'_{{\\rm CO}(J=3-2)} = 4.5 \\times 10^{10} K km/s pc^2, which corresponds to M({\\rm H}_2) = 3.6 times 10^10 M_{\\odot} if we adopt the CO-to-H_2 conversion factor of 0.8 M_{\\odot} (K km/s pc^2)^{-1}. This upper limit is comparable to L'_{{\\rm CO}(J=3-2)} (and thus the molecular gas mass) detected in quasars and BAL quasars at z=1-3, and no sign of the presence of the huge amount of molecular gas in this FeLo...

Ohta, K; Nakanishi, K; Aoki, K; Iwata, I; Akiyama, M; Tamura, N; Ando, M; Ohta, Kouji; Kiuchi, Gaku; Nakanishi, Kouichiro; Aoki, Kentaro; Iwata, Ikuru; Akiyama, Masayuki; Tamura, Naoyuki; Ando, Masataka

2007-01-01

176

Profile variability of the H-alpha and H-beta broad emission lines in NGC5548  

CERN Document Server

Between 1996 and 2002, we have carried out a spectral monitoring program for the Seyfert galaxy NGC 5548. High quality spectra (S/N>50), covering the spectral range (4000-7500)AA were obtained with the 6 m and 1 m telescopes of SAO (Russia) and with the 2.1 m telescope GHO (Mexico). We found that both the flux in the lines and the continuum gradually decreased, reaching minimum values during May-June 2002. The mean, rms, and the averaged over years, observed and difference line profiles of H-alpha and H-beta reveal the double peaked structure at the radial velocity ~+-1000km/s. The relative intensity of these peaks changes with time. During 1996, the red peak was the brightest, while in 1998 - 2002, the blue peak became the brighter one. In 2000-2002 a distinct third peak appeared in the red wing of H-alpha and H-beta line profiles. The radial velocity of this feature decreased between 2000 and 2002 from ~+2500 km/s to ~+2000 km/s. The fluxes of the various parts of the line profiles are well correlated with ...

Shapovalova, A I; Bochkarev, N G; Carrasco, A N B L; Chavushyan, V H; Collin, S; Valdés, J R; Borisov, N; Dumont, A M; Vlasuyk, V V; Chilingarian, I; Fioktistova, I S; Martinez, O M

2004-01-01

177

Initial Data Release from the INT Photometric H-alpha Survey of the Northern Galactic Plane (IPHAS)  

CERN Document Server

The INT/WFC Photometric H-alpha Survey of the Northern Galactic Plane (IPHAS) is an imaging survey being carried out in H-alpha, r' and i' filters, with the Wide Field Camera (WFC) on the 2.5-metre Isaac Newton Telescope (INT) to a depth of r'=20 (10 sigma). The survey is aimed at revealing large scale structure in our local galaxy, and also the properties of key early and late populations making up the Milky Way. Mapping emission line objects enables a particular focus on objects in the young and old stages of stellar evolution ranging from early T-Tauri stars to late planetary nebulae. In this paper we present the IPHAS Initial Data Release, primarily a photometric catalogue of about 200 million unique objects, coupled with associated image data covering about 1600 square degrees in three passbands. We note how access to the primary data products has been implemented through use of standard virtual observatory publishing interfaces. Simple traditional web access is provided to the main IPHAS photometric cat...

González-Solares, E A; Greimel, R; Drew, J E; Irwin, M J; Sale, S E; Andrews, K; Aungwerojwit, A; Barlow, M J; Besselaar, E van den; Corradi, R L M; Gänsicke, B T; Groot, P J; Hales, A S; Hopewell, E C; Hu, H; Irwin, J; Knigge, C; Lagadec, E; Leisy, P; Lewis, J R; Mampaso, A; Matsuura, M; Moont, B; Morales-Rueda, L; Morris, R A H; Naylor, T; Parker, Q A; Prema, P; Pyrzas, S; Rixon, G T; Rodríguez-Gil, P; Roelofs, G; Sabin, L; Skillen, I; Suso, J; Tata, R; Viironen, K; Vink, J S; Witham, A; Wright, N J; Zijlstra, A A; Zurita, A; Drake, J; Fabregat, J; Lennon, D J; Lucas, P W; Martín, E L; Steeghs, D; Unruh, Y C

2007-01-01

178

H{\\alpha} and UV luminosities and star formation rates in a large sample of luminous compact galaxies  

CERN Document Server

We present the results of a statistical study of the star formation rates (SFR) derived from the Galaxy Evolution Explorer (GALEX) observations in the ultraviolet continuum and in the H\\alpha emission line for a sample of about 800 luminous compact galaxies (LCGs). Galaxies in this sample have a compact structure and include one or several regions of active star formation. Global galaxy characteristics (metallicity, luminosity, stellar mass) are intermediate between ones of the nearby blue compact dwarf (BCD) galaxies and Lyman-break galaxies (LBGs) at high redshifts z > 2 - 3. SFRs were corrected for interstellar extinction which was derived from the optical Sloan Digital Sky Survey (SDSS) spectra. We find that SFRs derived from the galaxy luminosities in the far ultraviolet (FUV) and near ultraviolet (NUV) ranges vary in a wide range from 0.18 M_Sun/yr to 113 M_Sun/yr with median values of 3.8 M_Sun/yr and 5.2 M_Sun/yr, respectively. Simple regression relations are found for luminosities L(H\\alpha) and L(UV...

Parnovsky, S L; Izotov, Y I

2012-01-01

179

Light curves and H$\\alpha$ luminosities as indicators of $^{56}$Ni mass in type IIP supernovae  

CERN Document Server

The possibility is investigated that the H$\\alpha$ luminosity at the nebular epoch may be an additional indicator of $^{56}$Ni mass in type II supernovae with plateau (SNe IIP), on the basis of available photometry and spectra. We first derive the $^{56}$Ni mass from the $M_V$ magnitude on the radioactive tail using a standard approach. A confirmation of the correlation between $^{56}$Ni mass and plateau $M_V$ magnitude found recently by Hamuy (2003) is evident. There is strong evidence of a correlation between steepness of the $V$ light curve slope at the inflection time and the $^{56}$Ni mass. If confirmed, this relation may provide distance and extinction independent estimates of the amount of $^{56}$Ni in SNe IIP. We then apply upgraded radioactive models of H$\\alpha$ luminosity at the nebular epoch and claim that it may be a good indicator of $^{56}$Ni, if mass, energy and mixing properties vary moderately (within factor $\\sim 1.4$) among SNe IIP . This method of the $^{56}$Ni mass determination from H$\\...

Elmhamdi, A; Danziger, I J

2003-01-01

180

GHASP : an H alpha kinematic survey of spiral and irregular galaxies. V. Dark matter distribution in 36 nearby spiral galaxies  

CERN Multimedia

The results obtained from a study of the mass distribution of 36 spiral galaxies are presented. The galaxies were observed using Fabry-Perot interferometry as part of the GHASP survey. The main aim of obtaining high resolution H alpha 2D velocity fields is to define more accurately the rising part of the rotation curves which should allow to better constrain the parameters of the mass distribution. The H alpha velocities were combined with low resolution HI data from the literature, when available. Combining the kinematical data with photometric data, mass models were derived from these rotation curves using two different functional forms for the halo: an isothermal sphere and an NFW profile. For the galaxies already modeled by other authors, the results tend to agree. Our results point at the existence of a constant density core in the center of the dark matter halos rather than a cuspy core, whatever the type of the galaxy from Sab to Im. This extends to all types the result already obtained by other author...

Spano, M; Amram, P; Carignan, C; Epinat, B; Hernández, O

2007-01-01

 
 
 
 
181

A STARBURSTING PROTO-CLUSTER IN MAKING ASSOCIATED WITH A RADIO GALAXY AT z = 2.53 DISCOVERED BY H{alpha} IMAGING  

Energy Technology Data Exchange (ETDEWEB)

We report a discovery of a proto-cluster in vigorous assembly and hosting strong star-forming activities, associated with a radio galaxy USS 1558-003 at z = 2.53, as traced by wide-field narrow-band H{alpha} imaging with MOIRCS on the Subaru Telescope. We find 68 H{alpha} emitters with dust-uncorrected star formation rates (SFRs) down to 8.6 M{sub Sun} yr{sup -1}. Their spatial distribution indicates that there are three prominent clumps of H{alpha} emitters: one surrounding the radio galaxy, the second located at {approx}1.5 Mpc away to the southwest, and the third located between the two. These contiguous three systems are very likely to merge together in the near future and may grow to a single more massive cluster at a later time. While most H{alpha} emitters reside in the 'blue cloud' on the color-magnitude diagram, some emitters have very red colors with J - K{sub s} > 1.38(AB). Interestingly, such red H{alpha} emitters are located toward the faint end of the red sequence, and they tend to be located in high density clumps. We do not see any statistically significant difference in the distributions of individual SFRs or stellar masses of the H{alpha} emitters between the dense clumps and the other regions, suggesting that this is one of the notable sites where the progenitors of massive galaxies in the present-day clusters were in their vigorous formation phase. Finally, we find that H{alpha} emission of the radio galaxy is fairly extended spatially over {approx}4.''5. However, it is not as widespread as its Ly{alpha} halo, meaning that the Ly{alpha} emission is indeed severely extended by resonant scattering.

Hayashi, Masao; Kodama, Tadayuki; Tadaki, Ken-ichi; Koyama, Yusei [Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Tanaka, Ichi, E-mail: masao.hayashi@nao.ac.jp [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A' ohoku Place, Hilo, HI 96720 (United States)

2012-09-20

182

COMPARING H{alpha} AND H I SURVEYS AS MEANS TO A COMPLETE LOCAL GALAXY CATALOG IN THE ADVANCED LIGO/VIRGO ERA  

Energy Technology Data Exchange (ETDEWEB)

Identifying the electromagnetic counterparts of gravitational wave (GW) sources detected by upcoming networks of advanced ground-based interferometers will be challenging, due in part to the large number of unrelated astrophysical transients within the {approx}10-100 deg{sup 2} sky localizations. A potential way to greatly reduce the number of such false positives is to limit detailed follow-up to only those candidates near galaxies within the GW sensitivity range of {approx}200 Mpc for binary neutron star mergers. Such a strategy is currently hindered by the fact that galaxy catalogs are grossly incomplete within this volume. Here, we compare two methods for completing the local galaxy catalog: (1) a narrowband H{alpha} imaging survey and (2) an H I emission line radio survey. Using H{alpha} fluxes, stellar masses (M {sub *}), and star formation rates (SFRs) from galaxies in the Sloan Digital Sky Survey (SDSS), combined with H I data from the GALEX Arecibo SDSS Survey and the Herschel Reference Survey, we estimate that an H{alpha} survey with a luminosity sensitivity of L {sub H{alpha}} = 10{sup 40} erg s{sup -1} at 200 Mpc could achieve a completeness of f {sup H{alpha}} {sub SFR} Almost-Equal-To 75% with respect to total SFR, but only f{sub M* Star-Operator }{sup H{alpha}} approx. 33% with respect to M {sub *} (due to lack of sensitivity to early-type galaxies). These numbers are significantly lower than those achieved by an idealized spectroscopic survey due to the loss of H{alpha} flux resulting from resolving out nearby galaxies and the inability to correct for the underlying stellar continuum. An H I survey with sensitivity similar to the proposed WALLABY survey on ASKAP could achieve f{sub SFR}{sup H{sub I}} Almost-Equal-To 80% and f{sub M Star-Operator }{sup H{sub I}} Almost-Equal-To 50%, somewhat higher than that of the H{alpha} survey. Finally, both H{alpha} and H I surveys should achieve {approx}> 50% completeness with respect to the host galaxies of short-duration gamma-ray bursts, which may trace the population of binary neutron star mergers.

Metzger, Brian D. [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08542 (United States); Kaplan, David L. [Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI 53211 (United States); Berger, Edo, E-mail: bmetzger@astro.princeton.edu, E-mail: kaplan@uwm.edu, E-mail: eberger@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2013-02-20

183

A star-bursting proto-cluster in making associated to a radio galaxy at z=2.53 discovered by H_alpha imaging  

CERN Document Server

We report a discovery of a proto-cluster in vigorous assembly and hosting strong star forming activities, associated to a radio galaxy USS 1558-003 at z=2.53, as traced by a wide-field narrow-band H_alpha imaging with MOIRCS on Subaru Telescope. We find 68 H_alpha emitters with dust-uncorrected SFRs down to 8.6 Msun/yr. Their spatial distribution indicates that there are three prominent clumps of H_alpha emitters, one surrounding the radio galaxy and another located at ~1.5 Mpc away to the south-west, and the other located in between the two. These contiguous three systems are very likely to merge together in the near future and may grow to a single more massive cluster at later times. Whilst most H_alpha emitters reside in the "blue cloud" on the color--magnitude diagram, some emitters have very red colors with J-Ks>1.38(AB). Interestingly, such red H_alpha emitters are located towards the faint end of the red sequence, and they tend to be located in the high density clumps. We do not see any statistically s...

Hayashi, Masao; Tadaki, Ken-ichi; Koyama, Yusei; Tanaka, Ichi

2012-01-01

184

Star Formation Rates and Stellar Masses of H-alpha Selected Star-Forming Galaxies at z=0.84: A Quantification of the Downsizing  

CERN Document Server

In this work we analyze the physical properties of a sample of 153 star forming galaxies at z~0.84, selected by their H-alpha flux with a NB filter. B-band luminosities of the objects are higher than those of local star forming galaxies. Most of the galaxies are located in the blue cloud, though some objects are detected in the green valley and in the red sequence. After the extinction correction is applied virtually all these red galaxies move to the blue sequence, unveiling their dusty nature. A check on the extinction law reveals that the typical extinction law for local starbursts is well suited for our sample but with E(B-V)_stars=0.55 E(B-V)_gas. We compare star formation rates (SFR) measured with different tracers (H-alpha, UV and IR) finding that they agree within a factor of three after extinction correction. We find a correlation between the ratios SFR_FUV/SFR_H-alpha, SFR_IR/SFR_H-alpha and the EW(H-alpha) (i.e. weighted age) which accounts for part of the scatter. We obtain stellar mass estimation...

Villar, V; Pérez-González, P-G; Barro, G; Zamorano, J; Noeske, K G; Koo, D C

2011-01-01

185

Protoplanetary Disks in the Orion Nebula An H$\\alpha$ Fabry-Perot study and Astrobiological Aspects  

CERN Multimedia

In this paper, we present a briefly overview of the protoplanetary disks in the Orion Nebula, incluiding some astrobiological aspects and an H$\\alpha$ Fabry-Perot study of 16 of them. We found that Fabry-Perot interferometry constitutes an effective technique for the detection of proplyds. We also report heliocentric systemic velocities for the proplyds 82-336, 158-323, 158-326, 159-350, 161-314, 161-324, 163-317, 166-316, 167-317, 168-326, 170-337, 176-325, 177-341, 180-331, 197-427 and 244-440. The velocities were measured between 22-38 km s$^{-1}$.

De la Fuente-Acosta, E; Arias, L; Throop, H B; Ambrocio-Cruz, P; Fuente, Eduardo de la; Rosado, Margarita; Arias, Lorena; Throop, Patricia Ambrocio-Cruz & Henry B.

2002-01-01

186

Mass loss in HR 1040 /A0 Ia/ - Analysis of Mg II lambda 2802 and H-alpha  

Science.gov (United States)

It is pointed out that International Ultraviolet Explorer (IUE) data for several early A type supergiants are now available to complement the ground-based spectroscopic data available for these bright stars. An examination of the resonance doublet of Mg II in the A type supergiants reveals that HR 1040 (HD 21389) is the only star in the observational literature in which a violet-shifted, deep absorption line is present without complete saturation. From an unsaturated profile, a good estimate of Mg(+) density can be found by means of accurate radiative transfer calculations. A relation can then be derived between mass loss rate and ionization balance. When certain velocity-related quantities can be estimated from a Mg II line profile, the H-alpha provides an estimate of the mass loss rate. The present investigation is concerned with an application of these diagnostics to HR 1040.

Kunasz, P. B.; Morrison, N. D.; Spressart, B.

1983-01-01

187

A deterministic width function model  

Science.gov (United States)

Use of a deterministic fractal-multifractal (FM) geometric method to model width functions of natural river networks, as derived distributions of simple multifractal measures via fractal interpolating functions, is reported. It is first demonstrated that the FM procedure may be used to simulate natural width functions, preserving their most relevant features like their overall shape and texture and their observed power-law scaling on their power spectra. It is then shown, via two natural river networks (Racoon and Brushy creeks in the United States), that the FM approach may also be used to closely approximate existing width functions.

Puente, C. E.; Sivakumar, B.

188

A comparison between Pa alpha and H alpha emission: The relation between HII region mean reddening, local gas density and metallicity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We measure reddenings to HII regions in NGC 2903, NGC 1512, M51, NGC 4449 and NGC 6946 from Hubble Space Telescope Pa alpha and H alpha images. Extinctions range from A_V ~ 5 - 0 depending upon the galaxy. For the galaxies with HST images in both lines, NGC 2903, NGC 1512 and M51, the Pa alpha and H alpha emission are almost identical in morphology which implies that little emission from bright HII regions is hidden from view by regions of comparatively high extinction. The ...

Quillen, A. C.; Yukita, Mihoko

2000-01-01

189

Widths of magnetic twistor resonances  

International Nuclear Information System (INIS)

Evaluation of widths of magnetic twistor resonances, conditioned by long-wave torsion-type spherical nucleus oscillations is given within the framework of dissipative nuclear fluid-dynamics. It is assumed that dissipation of collective transverse oscillation energy is generated by nucleon-nucleon collisions leading finaly to nuclear Fermi-continuum viscosity. Analytic expressions for collision widths is given depending on the mass number, multipolarity and energy. 21 refs., 2 figs

1993-10-01

190

Discovery of an Apparent Nova in M81 and an Increase of H-alpha Emission from PNV J09553488+6910194  

Science.gov (United States)

We report the discovery of an apparent nova in M81 on a co-added 2000-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~1.5" seeing on 2014 Mar. ...

Hornoch, K.; Vaduvescu, O.; Stoev, H.

2014-03-01

191

Discovery of an Apparent Nova in M81 and H-alpha Confirmation of PNV J09560160+6903126 and PNV J09553945+6905557  

Science.gov (United States)

We report the discovery of an apparent nova in M81 galaxy on a co-added 2000-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~1.2" seeing on 2014 May 26.923 UT. ...

Hornoch, K.; Stoev, H.; Tudor, V.; Vaduvescu, O.; Frigo, M.

2014-05-01

192

Obscured star formation at z = 0.84 with HiZELS: the relationship between star formation rate and H-alpha or ultra-violet dust extinction  

CERN Multimedia

[Abridged] We compare H-alpha, ultraviolet (UV) and infrared (IR) indicators of star formation rate (SFR) for a sample of z = 0.84 galaxies from the High-z Emission Line Survey (HiZELS). Using multi-wavelength diagnostics, we estimate that 5 - 11 per cent of H-alpha emitters at this redshift are active galactic nuclei. We detect 35 per cent of the H-alpha emitters individually at 24 microns, and stack the star-forming emitters on deep 24-micron images in order to calculate the typical SFRs of our galaxies. These are compared to the observed H-alpha line fluxes in order to estimate the extinction at z = 0.84, and we find a significant increase in dust extinction for galaxies with higher SFRs. We demonstrate that the local relationship between SFR and extinction is suitable for our sample, and attribute the overall increase in dust extinction for z = 0.84 galaxies to an increase in the average SFR, rather than to a change in dust properties. We calculate the UV extinction, and find a similar dependence on SFR, ...

Garn, Timothy; Best, Philip N; Geach, James E; Smail, Ian; Cirasuolo, Michele; Dalton, Gavin B; Dunlop, James S; McLure, Ross J; Farrah, Duncan

2009-01-01

193

A search for clusters at high redshift - IV. Spectroscopy of H-alpha emitters in a proto-cluster at z=2.16  

CERN Multimedia

Radio galaxy PKS 1138-262 is a massive galaxy at z=2.16, located in a dense environment. We have found an overdensity of Ly-alpha emitting galaxies in this field, consistent with a proto-cluster structure associated with the radio galaxy. Recently, we have discovered forty candidate H-alpha emitters by their excess near infrared narrow band flux. Here, we present infrared spectroscopy of nine of the brightest candidate H-alpha emitters. All these candidates show an emission line at the expected wavelength. The identification of three of these lines with H-alpha is confirmed by accompanying [NII] emission. The spectra of the other candidates are consistent with H-alpha emission at z~2.15, one being a QSO as indicated by the broadness of its emission line. The velocity dispersion of the emitters (360 km/s) is significantly smaller than that of the narrow band filter used for their selection (1600 km/s). We therefore conclude that the emitters are associated with the radio galaxy. The star formation rates (SFRs)...

Kurk, J D; Overzier, R A; Röttgering, H J A; Miley, G K

2004-01-01

194

Large-Amplitude Oscillation of an Erupting Filament as Seen in EUV, H-alpha and Microwave Observations  

CERN Document Server

We present multiwavelength observations of a large-amplitude oscillation of a polar crown filament on 15 October 2002. The oscillation occurred during the slow rise (about 1 km/s) of the filament. It completed three cycles before sudden acceleration and eruption. The oscillation and following eruption were clearly seen in observations recorded by the Extreme-Ultraviolet Imaging Telescope onboard SOHO. The oscillation was seen only in a part of the filament, and it appears to be a standing oscillation rather than a propagating wave. The period of oscillation was about two hours and did not change significantly during the oscillation. We also identified the oscillation as a "winking filament" in the H-alpha images taken by the Flare Monitoring Telescope, and as a spatial displacement in 17 GHz microwave images from Nobeyama Radio Heliograph (NoRH). The filament oscillation seems to be triggered by magnetic reconnection between a filament barb and nearby emerging magnetic flux as was evident from the MDI magneto...

Isobe, H; Asai, A; Jain, R

2007-01-01

195

STAR FORMATION PROPERTIES IN THE LOCAL VOLUME GALAXIES VIA H{alpha} AND FAR-ULTRAVIOLET FLUXES  

Energy Technology Data Exchange (ETDEWEB)

A distance-limited sample of 869 objects from the Updated Nearby Galaxy Catalog is used to characterize the star formation status of the Local Volume population. We present a compiled list of 1217 star formation rate (SFR) estimates for 802 galaxies within 11 Mpc, derived from the H{alpha} imaging surveys and the GALEX far-ultraviolet survey. We briefly discuss some basic scaling relations between SFR and luminosity, morphology, H I mass, surface brightness, and the environment of the galaxies. About 3/4 of our sample consist of dwarf galaxies, for which we offer a more refined classification. We note that the specific SFR of nearly all luminous and dwarf galaxies does not exceed the maximum value: log (SFR/L{sub K} ) = -9.4 [yr{sup -1}]. Most spiral and blue dwarf galaxies have enough time to generate their stellar mass during the cosmological time, T{sub 0}, with the observed SFRs. They dispose of a sufficient amount of gas to support their present SFRs over the next T{sub 0} term. We note that only a small fraction of BCD, Im, and Ir galaxies (about 1/20) proceed in a mode of vigorous starburst activity. In general, the star formation history of spiral and blue dwarf galaxies is mainly driven by their internal processes. The present SFRs of E, S0, and dSph galaxies typically have 1/30-1/300 of their former activity.

Karachentsev, Igor D.; Kaisina, Elena I., E-mail: ikar@sao.ru, E-mail: kei@sao.ru [Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnij Arkhyz, Karachai-Cherkessian Republic 369167 (Russian Federation)

2013-09-15

196

Short timescale variations of the H{\\alpha} double-peaked profile of the nucleus of NGC 1097  

CERN Multimedia

The broad (FWHM ~ 10,000 km/s) double-peaked H{\\alpha} profile from the LINER/Seyfert 1 nucleus of NGC 1097 was discovered in 1991, and monitored for the following 11 years. The profile showed variations attributed to the rotation of gas in a non-axisymmetric Keplerian accretion disk, ionized by a varying radiatively inefficient accretion flow (RIAF) located in the inner parts of the disk. We present and model 11 new spectroscopic observations of the double-peaked profile taken between 2010 March and 2011 March. This series of observations was motivated by the finding that in 2010 March the flux in the double-peaked line was again strong, becoming, in 2010 December, even stronger than in the observations of a decade ago. We also discovered shorter timescale variations than in the previous observations: (1) the first, of ~7 days, is interpreted as due to "reverberation" of the variation of the ionizing source luminosity, and the timescale of 7 days as the light crossing time between the source and the accretio...

Schimoia, Jaderson S; Nemmen, Rodrigo S; Winge, Cláudia; Eracleous, Michael; 10.1088/0004-637X/748/2/145

2012-01-01

197

Star formation at z=1.47 from HiZELS: An H{\\alpha}+[OII] double-blind study  

CERN Multimedia

This paper presents the results from the first wide and deep dual narrow-band survey to select H-alpha (Ha) and [OII] line emitters at z=1.47\\pm0.02 (using matched narrow-band filters in the H and z' bands), exploiting synergies between the UKIRT and Subaru telescopes. The Ha survey at z=1.47 reaches a flux limit of ~7x10^-17 erg/s/cm^2 and detects ~200 Ha emitters over 0.7deg^2, while the much deeper [OII] survey reaches an effective flux of ~7x10^-18 erg/s/cm^2, detecting ~1400 z=1.47 [OII] emitters in a matched co-moving volume of ~2.5x10^5 Mpc^3. The combined survey results in the identification of 190 simultaneous Ha and [OII] emitters at z=1.47. Ha and [OII] luminosity functions are derived and both are shown to evolve significantly from z~0 in a consistent way. The star formation rate density of the Universe at z=1.47 is evaluated, with the Ha analysis yielding 0.16\\pm0.05 M_sun/yr/Mpc^3 and the [OII] analysis 0.17\\pm0.04 M_sun/yr/Mpc^3. The measurements are combined with other studies, providing a sel...

Sobral, David; Matsuda, Yuichi; Smail, Ian; Geach, James; Cirasuolo, Michele

2011-01-01

198

On the Nature of the Unique H$\\alpha$-Emitting T Dwarf 2MASS J12373919+6526148  

CERN Document Server

We explore and discount the hypothesis that the strong, continual H$\\alpha$-emitting T dwarf 2MASS J12373919+6526148 can be explained as a young, low gravity, very low mass brown dwarf. The source is already known to have a marginally-fainter absolute magnitude than similar T dwarfs with trigonometric parallax measurements, and has a tangential velocity consistent with old disk kinematics. Applying the technique of Burgasser, Burrows & Kirkpatrick on new near infrared spectroscopy for this source, estimates of its {\\teff}, $\\log{g}$ and metallicity ([M/H]) are obtained. 2M 1237+6526 has a {\\teff} $\\approx$ 800-850 K. If [M/H] is solar, $\\log{g}$ is as high as $\\sim$5.5 (cgs) and this source is older than 10 Gyr. We find a more plausible scenario to be a modestly subsolar metallicity ([M/H] = -0.2) and moderate $\\log{g}$ $\\sim$ 5.0, implying an age older than 2 Gyr and a mass greater than 0.035 M$_{\\sun}$. The alternative explanation of the unique emission of this source, involving an interacting, close, d...

Liebert, J; Liebert, James; Burgasser, Adam J.

2006-01-01

199

On the operator equivalents  

International Nuclear Information System (INIS)

A closed polynomial formula for the qth component of the diagonal operator equivalent of order k is derived in terms of angular momentum operators. The interest in various fields of molecular and solid state physics of using such a formula in connection with symmetry adapted operator equivalents is outlined

1978-01-01

200

THE PHOTOMETRIC AND KINEMATIC STRUCTURE OF FACE-ON DISK GALAXIES. III. KINEMATIC INCLINATIONS FROM H{alpha} VELOCITY FIELDS  

Energy Technology Data Exchange (ETDEWEB)

Using the integral field unit DensePak on the WIYN 3.5 m telescope we have obtained H{alpha} velocity fields of 39 nearly face-on disks at echelle resolutions. High-quality, uniform kinematic data and a new modeling technique enabled us to derive accurate and precise kinematic inclinations with mean i{sub kin} = 23 Degree-Sign for 90% of these galaxies. Modeling the kinematic data as single, inclined disks in circular rotation improves upon the traditional tilted-ring method. We measure kinematic inclinations with a precision in sin i of 25% at 20 Degree-Sign and 6% at 30 Degree-Sign . Kinematic inclinations are consistent with photometric and inverse Tully-Fisher inclinations when the sample is culled of galaxies with kinematic asymmetries, for which we give two specific prescriptions. Kinematic inclinations can therefore be used in statistical ''face-on'' Tully-Fisher studies. A weighted combination of multiple, independent inclination measurements yield the most precise and accurate inclination. Combining inverse Tully-Fisher inclinations with kinematic inclinations yields joint probability inclinations with a precision in sin i of 10% at 15 Degree-Sign and 5% at 30 Degree-Sign . This level of precision makes accurate mass decompositions of galaxies possible even at low inclination. We find scaling relations between rotation speed and disk-scale length identical to results from more inclined samples. We also observe the trend of more steeply rising rotation curves with increased rotation speed and light concentration. This trend appears to be uncorrelated with disk surface brightness.

Andersen, David R. [NRC Herzberg Institute of Astrophysics, 5071 W Saanich Road, Victoria, BC V9E 2E7 (Canada); Bershady, Matthew A., E-mail: david.andersen@nrc-cnrc.gc.ca, E-mail: mab@astro.wisc.edu [Department of Astronomy, University of Wisconsin, 475 N Charter Street, Madison, WI 53706 (United States)

2013-05-01

 
 
 
 
201

Calculation of extracted ion beam particle distribution including within-extractor collisions from H-alpha Doppler shift measurements.  

Science.gov (United States)

Prototype long pulse ion sources are being developed and tested toward the goal of a deuterium beam extraction of 120 keV/65 A. The latest prototype source consists of a magnetic bucket plasma generator and a four-grid copper accelerator system with multicircular apertures of 568 holes. To measure the angular divergence and the ion species of the ion beam, an optical multichannel analyzer (OMA) system for a Doppler-shifted H-alpha lights was set up at the end of a gas-cell neutralizer. But the OMA data are very difficult to analyze due to a large background level on the top of the three energy peaks (coming from H(+), H(2) (+), and H(3) (+)). These background spectra in the OMA signals seem to result from partially accelerated ion beams in the accelerator. Extracted ions could undergo a premature charge exchange as the accelerator column tends to have a high hydrogen partial pressure from the unused gas from the plasma generator, resulting in a continuous background of partially accelerated beam particles at the accelerator exit. This effect is calculated by accounting for all the possible atomic collision processes and numerically summing up three ion species across the accelerator column. The collection of all the atomic reaction cross sections and the numerical summing up will be presented. The result considerably depends on the background pressure and the ion beam species ratio (H(+), H(2) (+), and H(3) (+)). This effect constitutes more than 20% of the whole particle distribution. And the energy distribution of those suffering from collisions is broad and shows a broad maximum in the vicinity of the half and the third energy region. PMID:18315152

Kim, Tae-Seong; Kim, Jinchoon; In, Sang Ryul; Jeong, Seung Ho

2008-02-01

202

Hybrid Exotic Meson Decay Width  

CERN Multimedia

We present results of a decay width calculation for a hybrid exotic meson(h, JPC=1-+) in the decay channel h to pi+a1. This calculation uses quenched lattice QCD and Luescher's finite box method. Operators for the h and pi+a1 states are used in a correlation matrix which was expanded by varying the smearing and fuzzing levels at source and sink points. Scattering phase shifts for a discrete set of relative pi+a1 momenta are determined using eigenvalues of the correlation matrix and formulae derived by Luescher. The phase shift data is very sparse, but fits to a Breit-Wigner model are made, resulting in a decay width of about 80 MeV.

Cook, M S

2005-01-01

203

Topics in orbit equivalence  

CERN Multimedia

This volume provides a self-contained introduction to some topics in orbit equivalence theory, a branch of ergodic theory. The first two chapters focus on hyperfiniteness and amenability. Included here are proofs of Dye's theorem that probability measure-preserving, ergodic actions of the integers are orbit equivalent and of the theorem of Connes-Feldman-Weiss identifying amenability and hyperfiniteness for non-singular equivalence relations. The presentation here is often influenced by descriptive set theory, and Borel and generic analogs of various results are discussed. The final chapter is a detailed account of Gaboriau's recent results on the theory of costs for equivalence relations and groups and its applications to proving rigidity theorems for actions of free groups.

Kechris, Alexander S

2004-01-01

204

Neutron dose equivalent meter  

Energy Technology Data Exchange (ETDEWEB)

A neutron dose equivalent detector for measuring neutron dose capable of accurately responding to neutron energies according to published fluence to dose curves. The neutron dose equivalent meter has an inner sphere of polyethylene, with a middle shell overlying the inner sphere, the middle shell comprising RTV.RTM. silicone (organosiloxane) loaded with boron. An outer shell overlies the middle shell and comprises polyethylene loaded with tungsten. The neutron dose equivalent meter defines a channel through the outer shell, the middle shell, and the inner sphere for accepting a neutron counter tube. The outer shell is loaded with tungsten to provide neutron generation, increasing the neutron dose equivalent meter's response sensitivity above 8 MeV.

Olsher, Richard H. (Los Alamos, NM); Hsu, Hsiao-Hua (Los Alamos, NM); Casson, William H. (Los Alamos, NM); Vasilik, Dennis G. (Los Alamos, NM); Kleck, Jeffrey H. (Menlo Park, CA); Beverding, Anthony (Foster City, CA)

1996-01-01

205

Equivalent local Dirac potentials  

International Nuclear Information System (INIS)

A transformation is used to obtain sets of equivalent Lorentz scalar, Lorentz four-vector, and tensor optical potentials. These potentials are used in the Dirac equation for describing elastic scattering observables

1985-01-01

206

Connection between nonradial pulsations and stellar winds in massive stars. VI. Variability in H alpha, polarization, and magnetic fields in early-type stars  

International Nuclear Information System (INIS)

The early-type stars whose spectra show Balmer emission lines are considered, taking into account the division of these stars into two groups, including the OB supergiants and the Be stars. In the case of the Be stars, recent observations at H-alpha, H-beta, and H-gamma with best S/N approximately 500 and resolution approximately 0.1 A have revealed a previously unsuspected winebottle, or two-tier, structure to the symmetric emission profile in several Be stars. For many Be stars, the circumstellar material has an apparent two-component structure. Attention is given to H-alpha variations in four typical Be stars, linear polarization, and magnetic fields. 23 references

1986-01-01

207

H-alpha images of the Cygnus Loop - A new look at shock-wave dynamics in an old supernova remnant  

Science.gov (United States)

Attention is given to deep H-alpha images of portions of the east, west, and southwest limbs of the Cygnus Loop which illustrate several aspects of shock dynamics in a multiphase interstellar medium. An H-alpha image of the isolated eastern shocked cloud reveals cloud deformation and gas stripping along the cloud's edges, shock front diffraction and reflection around the rear of the cloud, and interior remnant emission due to upstream shock reflection. A faint Balmer-dominated filament is identified 30 arcmin further west of the remnant's bright line of western radiative filaments. This detection indicates a far more westerly intercloud shock front position than previously realized, and resolves the nature of the weak X-ray, optical, and nonthermal radio emission observed west of NGC 6960. Strongly curved Balmer-dominated filaments along the remnant's west and southwest edge may indicate shock diffraction caused by shock wave passage in between clouds.

Fesen, Robert A.; Kwitter, Karen B.; Downes, Ronald A.

1992-01-01

208

Chromospheric Ca II H and K and H-alpha emission in single and binary stars of spectral types F6-M2  

International Nuclear Information System (INIS)

New observations of the Ca II H and K and H-epsilon region and/or the Balmer H-alpha line are presented for 100 mostly very active stars but also for weak or inactive stars with suspected activity. Correlations between chromospheric activity at Ca II H and K and H-alpha and effective surface temperature and rotation are identified, and several new stars with chromospheric Ca II H and K emission are discovered. No single activity-rotation relation can be derived for all luminosity classes, and there is clear evidence that evolved stars are generally more active than main-sequence stars of the same rotation period. Binary within the evolved stars appears to play no role, while main-sequence binary stars show generally higher levels of activity than their single counterparts. Chromospheric emission in the Ca II H and K lines depends on surface temperature in that flux declines with cooler temperature. 63 refs

1990-01-01

209

H-alpha Observations of a Large Sample of Galaxies at z~2: Implications for Star Formation in High Redshift Galaxies  

CERN Document Server

Using H-alpha spectra of 114 rest-frame UV-selected galaxies at z~2, we compare inferred star formation rates (SFRs) with those determined from the UV continuum luminosity. After correcting for extinction using standard techniques based on the UV continuum slope, we find excellent agreement between the indicators, with = 31 Msun/yr and = 29 Msun/yr. The agreement between the indicators suggests that the UV luminosity is attenuated by an typical factor of ~4.5 (with a range from no attenuation to a factor of ~100 for the most obscured object in the sample), in good agreement with estimates of obscuration from X-ray, radio and mid-IR data. The H-alpha luminosity is attenuated by a factor of ~1.7 on average, and the maximum H-alpha attenuation is a factor of ~5. In agreement with X-ray and mid-IR studies, we find that the SFR increases with increasing stellar mass and at brighter K magnitudes, to ~ 60 Msun/yr for galaxies with K10^11 Msun) have had higher SFRs in the past.

Erb, D K; Shapley, A E; Pettini, M; Reddy, N A; Adelberger, K L; Erb, Dawn K.; Steidel, Charles C.; Shapley, Alice E.; Pettini, Max; Reddy, Naveen A.; Adelberger, Kurt L.

2006-01-01

210

H-alpha Imaging with HST+NICMOS of An Elusive Damped Ly-alpha Cloud at z=0.6  

CERN Multimedia

Despite previous intensive ground--based imaging and spectroscopic campaigns and wide-band HST imaging of the z=0.927 QSO 3C336 field, the galaxy that hosts the damped Ly-alpha system along this line--of--sight has eluded detection. We present a deep narrow-band H-alpha image of the field of this z=0.656 damped Ly-alpha absorber, obtained through the F108N filter of NICMOS 1 onboard the Hubble Space Telescope. The goal of this project was to detect any H-alpha emission 10 times closer than previous studies to unveil the damped absorber. We do not detect H-alpha emission between 0.05'' and 6'' (0.24 and 30 $h^{-1}$ kpc) from the QSO, with a 3-sigma flux limit of $3.70 \\times 10^{-17} h^{-2}$ erg/s/cm^2 for an unresolved source, corresponding to a star formation rate (SFR) of $0.3 h^{-2}$ M_sun/yr. This leads to a 3-sigma upper limit of 0.15 M_sun/yr/kpc^2 on the SFR density, or a maximum SFR of 1.87 M_sun/yr assuming a disk of 4 kpc in diameter. This result adds to the number of low redshift damped Ly-alpha ab...

Bouche, N; Charlton, J C; Bershady, M A; Churchill, C W; Steidel, C C; Bouche, Nicolas; Lowenthal, James D.; Charlton, Jane C.; Bershady, Matthew A.; Churchill, Christopher W.; Steidel, Charles C.

2000-01-01

211

Orbifold equivalent potentials  

CERN Document Server

To a graded finite-rank matrix factorisation of the difference of two homogeneous potentials one can assign two numbers, the left and right quantum dimension. The existence of such a matrix factorisation with non-zero quantum dimensions defines an equivalence relation between potentials, giving rise to non-obvious equivalences of categories. Restricted to ADE singularities, the resulting equivalence classes of potentials are those of type {A_{d-1}} for d odd, {A_{d-1},D_{d/2+1}} for d even but not in {12,18,30}, and {A_{11}, D_7, E_6}, {A_{17}, D_{10}, E_7} and {A_{29}, D_{16}, E_8}. This is the result expected from two-dimensional rational conformal field theory, and it directly leads to new descriptions of and relations between the associated (derived) categories of matrix factorisations and Dynkin quiver representations.

Carqueville, Nils; Runkel, Ingo

2013-01-01

212

Triangular homotopy equivalences  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A map $f:X\\to Y$ to a simplicial complex $Y$ is called a $Y$-triangular homotopy equivalence if it has a homotopy inverse $g$ and homotopies $h_1:f\\circ g\\simeq \\mathrm{id}_Y$, $h_2:g\\circ f\\simeq \\mathrm{id}_X$ such that for all simplices $\\sigma\\in Y$, $f|_\\sigma:f^{-1}(\\sigma) \\to \\sigma$ is a homotopy equivalence with inverse $g|_\\sigma:\\sigma \\to f^{-1}(\\sigma)$ and homotopies $h_1|_\\sigma$ and $h_2|_\\sigma$. In this paper we prove that for all pairs $X,Y$ of finite-dim...

Adams-florou, Spiros

2013-01-01

213

Asymptotic equivalence and summability  

Directory of Open Access Journals (Sweden)

Full Text Available This paper is a study of the relatioship. between the asymptotic equivalence of two sequences (limnxn/yn=1 and three variatious of this equivalence for a sequence-to-sequence transformation A, the three variations are give by the ratios RmAx/RmAy. SmAx/SmAy, And μmAx/μmAy, where RmAz:=∑n≥m|(Azn|, SmAz:=∑n≤m|(Azn|, and μmAz:=supn≥m|(Azn|.

Mousa S. Marouf

1993-12-01

214

Equivalent Colorings with "Maple"  

Science.gov (United States)

Many counting problems can be modeled as "colorings" and solved by considering symmetries and Polya's cycle index polynomial. This paper presents a "Maple 7" program link http://users.tamuk.edu/kfdrc00/ that, given Polya's cycle index polynomial, determines all possible associated colorings and their partitioning into equivalence classes. These…

Cecil, David R.; Wang, Rongdong

2005-01-01

215

Reflective-coreflective equivalence  

CERN Document Server

We explore a curious type of equivalence between certain pairs of reflective and coreflective subcategories. We illustrate with examples involving noncommutative duality for C*-dynamical systems and compact quantum groups, as well as examples where the subcategories are actually isomorphic.

Bédos, Erik; Quigg, John

2010-01-01

216

Radioactive waste equivalence  

International Nuclear Information System (INIS)

The report reviews, for the Member States of the European Community, possible situations in which an equivalence concept for radioactive waste may be used, analyses the various factors involved, and suggests guidelines for the implementation of such a concept. Only safety and technical aspects are covered. Other aspects such as commercial ones are excluded. Situations where the need for an equivalence concept has been identified are processes where impurities are added as a consequence of the treatment and conditioning process, the substitution of wastes from similar waste streams due to the treatment process, and exchange of waste belonging to different waste categories. The analysis of factors involved and possible ways for equivalence evaluation, taking into account in particular the chemical, physical and radiological characteristics of the waste package, and the potential risks of the waste form, shows that no simple all-encompassing equivalence formula may be derived. Consequently, a step-by-step approach is suggested, which avoids complex evaluations in the case of simple exchanges

1990-01-01

217

Equivalent Crystal Planes Animation  

Science.gov (United States)

This is a 3-D animation of equivalent crystal planes. It shows the Miller indices linking nodes as a corresponding binary family within braces. This animation is approximately 13 seconds in length and would be useful for understanding the conceptual/imaginary planes have on the crystal behavior.

2009-07-22

218

Correspondences. Equivalence relations  

International Nuclear Information System (INIS)

We comment on sections paragraph 3 'Correspondences' and paragraph 6 'Equivalence Relations' in chapter II of 'Elements de mathematique' by N. Bourbaki in order to simplify their comprehension. Paragraph 3 exposes the ideas of a graph, correspondence and map or of function, and their composition laws. We draw attention to the following points: 1) Adopting the convention of writting from left to right, the composition law for two correspondences (A,F,B), (U,G,V) of graphs F, G is written in full generality (A,F,B)o(U,G,V) = (A,FoG,V). It is not therefore assumed that the co-domain B of the first correspondence is identical to the domain U of the second (EII.13 D.7), (1970). 2) The axiom of choice consists of creating the Hilbert terms from the only relations admitting a graph. 3) The statement of the existence theorem of a function h such that f = goh, where f and g are two given maps having the same domain (of definition), is completed if h is more precisely an injection. Paragraph 6 considers the generalisation of equality: First, by 'the equivalence relation associated with a map f of a set E identical to (x is a member of the set E and y is a member of the set E and x:f = y:f). Consequently, every relation R(x,y) which is equivalent to this is an equivalence relation in E (symmetrical, transitive, reflexive); then R admits a graph included in E x E, etc. Secondly, by means of the Hilbert term of a relation R submitted to the equivalence. In this last case, if R(x,y) is separately collectivizing in x and y, theta(x) is not the class of objects equivalent to x for R (EII.47.9), (1970). The interest of bringing together these two subjects, apart from this logical order, resides also in the fact that the theorem mentioned in 3) can be expressed by means of the equivalence relations associated with the functions f and g. The solutions of the examples proposed reveal their simplicity

1978-01-01

219

The equivalence theorem  

International Nuclear Information System (INIS)

The equivalence theorem states that, at an energy E much larger than the vector-boson mass M, the leading order of the amplitude with longitudinally polarized vector bosons on mass shell is given by the amplitude in which these vector bosons are replaced by the corresponding Higgs ghosts. We prove the equivalence theorem and show its validity in every order in perturbation theory. We first derive the renormalized Ward identities by using the diagrammatic method. Only the Feynman-- 't Hooft gauge is discussed. The last step of the proof includes the power-counting method evaluated in the large-Higgs-boson-mass limit, needed to estimate the leading energy behavior of the amplitudes involved. We derive expressions for the amplitudes involving longitudinally polarized vector bosons for all orders in perturbation theory. The fermion mass has not been neglected and everything is evaluated in the region mf?M much-lt E much-lt mHiggs

1990-04-01

220

Quantum Equivalence Principle  

CERN Multimedia

A simple mapping procedure is presented by which classical orbits and path integrals for the motion of a point particle in flat space can be transformed directly into those in curved space with torsion. Our procedure evolved from well-established methods in the theory of plastic deformations, where crystals with defects are described mathematically as images of ideal crystals under active nonholonomic coordinate transformations. Our mapping procedure may be viewed as a natural extension of Einstein's famous equivalence principle. When applied to time-sliced path integrals, it gives rise to a new quantum equivalence principle which determines short-time action and measure of fluctuating orbits in spaces with curvature and torsion. The nonholonomic transformations possesses a nontrivial Jacobian in the path measure which produces in a curved space an additional term proportional to the curvature scalar R, thus canceling a similar term found earlier by DeWitt. This cancelation is important for correctly describi...

Kleinert, H

1996-01-01

 
 
 
 
221

A Study of Selection Methods for H alpha Emitting Galaxies at z~1.3 for the Subaru/FMOS Galaxy Redshift Survey for Cosmology (FastSound)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The efficient selection of high-redshift emission galaxies is important for future large galaxy redshift surveys for cosmology. Here we describe the target selection methods for the FastSound project, a redshift survey for H alpha emitting galaxies at z=1.2-1.5 using Subaru/FMOS to measure the linear growth rate f\\sigma 8 via Redshift Space Distortion (RSD) and constrain the theory of gravity. To select ~400 target galaxies in the 0.2 deg^2 FMOS field-of-view from photometri...

Tonegawa, Motonari; Totani, Tomonori; Akiyama, Masayuki; Dalton, Gavin; Glazebrook, Karl; Iwamuro, Fumihide; Sumiyoshi, Masanao; Tamura, Naoyuki; Yabe, Kiyoto; Coupon, Jean; Goto, Tomotsugu; Spitler, Lee R.

2013-01-01

222

Luminosities and Star Formation Rates Of Galaxies Observed With the Ultraviolet Imaging Telescope A Comparison of Far-UV, H-$\\alpha$, and Far-IR Diagnostics  

CERN Multimedia

During the UIT/Astro Spacelab missions, the Ultraviolet Imaging Telescope obtained spatially resolved far-UV (lambda 1500 A) imagery of ~35 galaxies exhibiting recent massive star formation. The sample includes disk systems, irregular, dwarf, and blue compact galaxies. The objects span an observed FUV luminosity range from -17 to -22 magnitudes. We estimate global star formation rates by comparing the observed FUV fluxes to the predictions of stellar population models, and compare the FUV-derived astration rates to those derived from H-alpha and far-IR photometry.

Fanelli, M N; Fanelli, Michael N.; Stecher, Theodore P.

1997-01-01

223

The H$\\alpha$ line forming region of AB Aur spatially resolved at sub-AU with the VEGA/CHARA spectro-interferometer  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A crucial issue in star formation is to understand the physical mechanism by which mass is accreted onto and ejected by a young star. The visible spectrometer VEGA on the CHARA array can be an efficient means of probing the structure and the kinematics of the hot circumstellar gas at sub-AU. For the first time, we observed the Herbig Ae star AB Aur in the H$\\alpha$ emission line, using the VEGA low spectral resolution on two baselines of the array. We computed and calibrated...

Perraut, K.; Benisty, M.; Mourard, D.; Rajabi, S.; Bacciotti, F.; Be?rio, Ph; Bonneau, D.; Chesneau, O.; Clausse, J. M.; Delaa, O.; Marcotto, A.; Roussel, A.; Spang, A.; Stee, Ph; Tallon-bosc, I.

2010-01-01

224

14 CFR 121.95 - Route width.  

Science.gov (United States)

... 2009-01-01 2009-01-01 false Route width. 121.95 Section 121.95 Aeronautics...AND SUPPLEMENTAL OPERATIONS Approval of Routes: Domestic and Flag Operations § 121.95 Route width. (a) Approved routes and...

2009-01-01

225

14 CFR 121.115 - Route width.  

Science.gov (United States)

... 2009-01-01 2009-01-01 false Route width. 121.115 Section 121.115 ...SUPPLEMENTAL OPERATIONS Approval of Areas and Routes for Supplemental Operations § 121.115 Route width. (a) Routes and route...

2009-01-01

226

WINGS-SPE. III. Equivalent width measurements, spectral properties, and evolution of local cluster galaxies  

Science.gov (United States)

Context. Cluster galaxies are the ideal sites to look at when studying the influence of the environment on the various aspects of the evolution of galaxies, such as the changes in their stellar content and morphological transformations. In the framework of wings, the WIde-field Nearby Galaxy-cluster Survey, we have obtained optical spectra for ~6000 galaxies selected in fields centred on 48 local (0.04 http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/566/A32 and by querying the wings database at http://web.oapd.inaf.it/wings/new/index.htmlAppendices are available in electronic form at http://www.aanda.org

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

2014-06-01

227

Formal and finite order equivalences  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We show that two families of germs of real-analytic subsets in Cn are formally equivalent if and only if they are equivalent of any finite order. We further apply the same technique to obtain analogous statements for equivalences of real-analytic self-maps and vector fields under conjugations. On the other hand, we provide an example of two sets of germs of smooth curves that are equivalent of any finite order but not formally equivalent.

2011-01-01

228

Equivalence Principle in Cosmology  

CERN Document Server

We analyse the Einstein equivalence principle (EEP) for a Hubble observer in Friedmann-Lemaitre-Robertson-Walker spacetime. We show that the affine structure of light cone in the FLRW spacetime should be treated locally in terms of the optical metric which is not reduced to the Minkowski metric due to the non-uniform parametrization of the local equations of light propagation with the proper time of the observer's clock. The physical consequence of this difference is that the Doppler shift of radio waves measured locally, is affected by the Hubble expansion.

Kopeikin, Sergei

2013-01-01

229

Equivalence of Dual Graphs  

Directory of Open Access Journals (Sweden)

Full Text Available Because of interesting and useful geometric as well as topological properties, alternating knots (links were regarded to have an important role in knot theory and 3-manifold theory. Many knots with crossing number less than 10 are alternating. It was the properties of alternating knots that enable the earlier knot tabulators to construct tables with relatively few mistakes or omissions. Graphs of knots (links have been repeatedly employed in knot theory. This article is devoted to establish relationship between knots and planar graphs. This relationship not only enables us see the equivalence of the graphs corresponding to black regions and the dual graph corresponding to white regions.

M. Azram

2013-07-01

230

Comparing H-alpha and HI Surveys as Means to a Complete Local Galaxy Catalog in the Advanced LIGO/Virgo Era  

CERN Document Server

Identifying the electromagnetic counterparts of gravitational wave (GW) sources detected by upcoming networks of advanced ground-based interferometers will be challenging due in part to the large number of unrelated astrophysical transients within the ~10-100 square degree sky localizations. A potential way to greatly reduce the number of such false positives is to limit detailed follow-up to only those candidates near galaxies within the GW sensitivity range of ~200 Mpc for binary neutron star mergers. Such a strategy is currently hindered by the fact that galaxy catalogs are grossly incomplete within this volume. Here we compare two methods for completing the local galaxy catalog: (1) a narrow-band H-alpha imaging survey; and (2) an HI emission line radio survey. Using H-alpha fluxes, stellar masses (M_star), and star formation rates (SFR) from galaxies in the Sloan Digital Sky Survey (SDSS), combined with HI data from the GALEX Arecibo SDSS Survey and the Herschel Reference Survey, we estimate that a H-alp...

Metzger, Brian D; Berger, Edo

2012-01-01

231

The environmental impacts on the star formation main sequence: an H-alpha study of the newly discovered rich cluster at z=1.52  

CERN Document Server

We report the discovery of a strong over-density of galaxies in the field of a radio galaxy at z=1.52 (4C65.22) based on our broad-band and narrow-band (H-alpha) photometry with Subaru Telescope. We find that H-alpha emitters are located in the outskirts of the density peak (cluster core) dominated by passive red-sequence galaxies. This resembles the situation in lower-redshift clusters, suggesting that the newly discovered structure is a well-evolved rich galaxy cluster at z=1.5. Our data suggest that the color-density and stellar mass-density relations are already in place at z~1.5, mostly driven by the passive red massive galaxies residing within Rc<200 kpc from the cluster core. These environmental trends almost disappear when we consider only star-forming (SF) galaxies. We do not find SFR-density or SSFR-density relations amongst SF galaxies, and the location of the SF main sequence does not significantly change with environment. Nevertheless, we find a tentative hint that star-bursting galaxies (up-s...

Koyama, Yusei; Tadaki, Ken-ichi; Hayashi, Masao; Tanaka, Ichi; Shimakawa, Rhythm

2014-01-01

232

Development of an Advanced Automated Method for Solar Filament Recognition and Its Scientific Application to a Solar Cycle of MLSO H\\alpha\\ Data  

CERN Document Server

We developed a method to automatically detect and trace solar filaments in H\\alpha\\ full-disk images. The program is able not only to recognize filaments and determine their properties, such as the position, the area, the spine, and other relevant parameters, but also to trace the daily evolution of the filaments. The program consists of three steps: First, preprocessing is applied to correct the original images; Second, the Canny edge-detection method is used to detect filaments; Third, filament properties are recognized through the morphological operators. To test the algorithm, we applied it to the observations from the Mauna Loa Solar Observatory (MLSO), and the program is demonstrated to be robust and efficient. H\\alpha\\ images obtained by MLSO from 1998 to 2009 are analyzed, and a butterfly diagram of filaments is obtained. It shows that the latitudinal migration of solar filaments has three trends in the Solar Cycle 23: The drift velocity was fast from 1998 to the solar maximum; After the solar maximum...

Hao, Qi; Chen, P F

2013-01-01

233

The H-alpha Variations of the Luminous Blue Variable P Cygni: Discrete Absorption Components and the Short S Doradus Phase  

CERN Multimedia

P Cygni is a prototype of the Luminous Blue Variables (or S Doradus variables), and the star displays photometric and emission line variability on a timescale of years (known as the "short S Doradus phase" variations). Here we present new high resolution H-alpha spectroscopy of P Cyg that we combine with earlier spectra and concurrent V-band photometry to document the emission and continuum flux variations over a 24 y time span. We show that the emission and continuum fluxes vary in concert on timescales of 1.6 y and longer, but differ on shorter timescales. The H-alpha profile shape also varies on the photometric timescales, and we describe the observed co-variations of the emission peak and absorption trough properties. We argue that the episodes of photometric and emission brightening are caused by increases in the size of the emission region that are related to variations in wind mass loss rate and outflow speed. We find evidence of blueward accelerating, Discrete Absorption Components (DACs) in the absor...

Ricahrdson, Noel D; Gies, Douglas R; Markova, N; Hesselbach, Erica N; Percy, J R

2011-01-01

234

Macroclumping as solution of the discrepancy between H{\\alpha} and P v mass loss diagnostics for O-type stars  

CERN Multimedia

Recent studies of O-type stars demonstrated that discrepant mass-loss rates are obtained when different diagnostic methods are employed - fitting the unsaturated UV resonance lines (e.g. P v) gives drastically lower values than obtained from the H{\\alpha} emission. Wind clumping may be the main cause for this discrepancy. In a previous paper, we have presented 3-D Monte-Carlo calculations for the formation of scattering lines in a clumped stellar wind. In the present paper we select five O-type supergiants (from O4 to O7) and test whether the reported discrepancies can be resolved this way. In the first step, the analyses start with simulating the observed spectra with Potsdam Wolf-Rayet (PoWR) non-LTE model atmospheres. The mass-loss rates are adjusted to fit best to the observed H{\\alpha} emission lines. For the unsaturated UV resonance lines (i.e. P v) we then apply our 3-D Monte-Carlo code, which can account for wind clumps of any optical depths, a non-void inter-clump medium, and a velocity dispersion in...

Šurlan, B; Aret, A; Kubát, J; Oskinova, L M; Torres, A F

2013-01-01

235

A very young, compact bipolar H$_2$O maser outflow in the intermediate-mass star-forming LkH$\\alpha$ 234 region  

CERN Document Server

We report multi-epoch VLBI H$_2$O maser observations towards the compact cluster of YSOs close to the Herbig Be star LkH$\\alpha$ 234. This cluster includes LkH$\\alpha$ 234 and at least nine more YSOs that are formed within projected distances of $\\sim$10 arcsec ($\\sim$9,000 au). We detect H$_2$O maser emission towards four of these YSOs. In particular, our VLBI observations (including proper motion measurements) reveal a remarkable very compact ($\\sim$0.2 arcsec = $\\sim$180 au), bipolar H$_2$O maser outflow emerging from the embedded YSO VLA 2. We estimate a kinematic age of $\\sim$40 yr for this bipolar outflow, with expanding velocities of $\\sim$20 km s$^{-1}$ and momentum rate $\\dot M_w V_w$ $\\simeq$ $10^{-4}-10^{-3}$ M$_{\\odot}$ yr$^{-1}$ km s$^{-1}$$\\times (\\Omega$/$4\\pi)$, powered by a YSO of a few solar masses. We propose that the outflow is produced by recurrent episodic jet ejections associated with the formation of this YSO. Short-lived episodic ejection events have previously been found towards high...

Torrelles, J M; Estalella, R; Anglada, G; Gómez, J F; Cantó, J; Patel, N A; Trinidad, M A; Girart, J M; Carrasco-González, C; Rodríguez, L F

2014-01-01

236

The H$\\alpha$ line forming region of AB Aur spatially resolved at sub-AU with the VEGA/CHARA spectro-interferometer  

CERN Document Server

A crucial issue in star formation is to understand the physical mechanism by which mass is accreted onto and ejected by a young star. The visible spectrometer VEGA on the CHARA array can be an efficient means of probing the structure and the kinematics of the hot circumstellar gas at sub-AU. For the first time, we observed the Herbig Ae star AB Aur in the H$\\alpha$ emission line, using the VEGA low spectral resolution on two baselines of the array. We computed and calibrated the spectral visibilities between 610 nm and 700 nm. To simultaneously reproduce the line profile and the visibility, we used a 1-D radiative transfer code that calculates level populations for hydrogen atoms in a spherical geometry and synthetic spectro-interferometric observables. We clearly resolved AB Aur in the H$\\alpha$ line and in a part of the continuum, even at the smallest baseline of 34 m. The small P-Cygni absorption feature is indicative of an outflow but could not be explained by a spherical stellar wind model. Instead, it f...

Perraut, K; Mourard, D; Rajabi, S; Bacciotti, F; Bério, Ph; Bonneau, D; Chesneau, O; Clausse, J M; Delaa, O; Marcotto, A; Roussel, A; Spang, A; Stee, Ph; Tallon-Bosc, I; McAlister, H; Brummelaar, T ten; Sturmann, J; Sturmann, L; Turner, N; Farrington, C; Goldfinger, P J

2010-01-01

237

M/L, H-alpha Rotation Curves, and HI Measurements for 329 Nearby Cluster and Field Spirals: III. Evolutionin Fundamental Galaxy Parameters  

CERN Document Server

We have conducted a study of optical and HI properties of spiral galaxies (size, luminosity, H-alpha flux distribution, circular velocity, HI gas mass) to investigate causes (e.g., nature versus nurture) for variation within the cluster environment. We find HI deficient cluster galaxies to be offset in Fundamental Plane space, with disk scale lengths decreased by a factor of 25%. This may be a relic of early galaxy formation, caused by the disk coalescing out of a smaller, denser halo (e.g., higher concentration index) or by truncation of the hot gas envelope due to the enhanced local density of neighbors, though we cannot completely rule out the effect of the gas stripping process. The spatial extent of H-alpha flux and the B-band radius also decreases, but only in early type spirals, suggesting that gas removal is less efficient within steeper potential wells (or that stripped late type spirals are quickly rendered unrecognizable). We find no significant trend in stellar mass-to-light ratios or circular vel...

Vogt, N P; Giovanelli, R; Herter, T; Vogt, Nicole P.; Haynes, Martha P.; Giovanelli, Riccardo; Herter, Terry

2004-01-01

238

Detonation cell widths in hydrogen-air-diluent mixtures  

International Nuclear Information System (INIS)

In this paper I report on the influence of steam and carbon dioxide on the detonability of hydrogen-air mixtures. Data were obtained on the detonation cell width in a heated detonation tube that is 0.43 m in diameter and 13.1 m long. The detonation cell widths were correlated using a characteristic length calculated from a chemical kinetic model. The addition of either diluent to a hydrogen-air mixture increased the cell width for all equivalence ratios. For equal diluent concentrations, however, carbon dioxide not only yielded larger increases in the cell width than steam, but its efficacy relative to steam was predicted to increase with increasing concentration. The range of detonable hydrogen concentrations in a hydrogen-air mixture initially at 1 atm pressure was found to be between 11.6 percent and 74.9 percent for mixtures at 20 degree C and 9.4 percent and 76.9 percent for mixtures at 100 degree C. The detonation limit was between 38.8 percent and 40.5 percent steam for a stoichiometric hydrogen-air-steam mixture initially at 100 degree C and 1 atm. 10 refs., 4 figs., 1 tab

1990-10-14

239

The narrow X-ray tail and double H-alpha tails of ESO 137-002 in Abell 3627  

CERN Document Server

We present the analysis of a deep Chandra observation of a ~2L_* late-type galaxy, ESO 137-002, in the closest rich cluster A3627. The Chandra data reveal a long (>40 kpc) and narrow tail with a nearly constant width (~3 kpc) to the southeast of the galaxy, and a leading edge ~1.5 kpc from the galaxy center on the upstream side of the tail. The tail is most likely caused by the nearly edge-on stripping of ESO 137-002's ISM by ram pressure, compared to the nearly face-on stripping of ESO 137-001 discussed in our previous work. Spectral analysis of individual regions along the tail shows that the gas throughout it has a rather constant temperature, ~1 keV, very close to the temperature of the tails of ESO 137-001, if the same atomic database is used. The derived gas abundance is low (~0.2 solar with the single-kT model), an indication of the multiphase nature of the gas in the tail. The mass of the X-ray tail is only a small fraction (<5%) of the initial ISM mass of the galaxy, suggesting that the stripping ...

Zhang, B; Ji, L; Sarazin, C; Lin, X B; Nulsen, P E J; Roediger, E; Donahue, M; Forman, W; Jones, C; Voit, G M; Kong, X

2013-01-01

240

Degravitation of the Cosmological Constant and Graviton Width  

CERN Document Server

We study the possibility of decoupling gravity from the vacuum energy. This is effectively equivalent to promoting Newton's constant to a high-pass filter that degravitates sources of characteristic wavelength larger than a certain macroscopic (super) horizon scale L. We study the underlying physics and the consistency of this phenomenon. In particular, the absence of ghosts, already at the linear level, implies that in any such theory the graviton should either have a mass 1/L, or be a resonance of similar width. This has profound physical implications for the degravitation idea.

Dvali, Gia; Khoury, J; Dvali, Gia; Hofmann, Stefan; Khoury, Justin

2007-01-01

 
 
 
 
241

Establishing Substantial Equivalence: Proteomics  

Science.gov (United States)

Wheat is a major crop in world agriculture and is consumed after processing into a range of food products. It is therefore of great importance to determine the consequences (intended and unintended) of transgenesis in wheat and whether genetically modified lines are substantially equivalent to those produced by conventional plant breeding. Proteomic analysis is one of several approaches which can be used to address these questions. Two-dimensional PAGE (2D PAGE) remains the most widely available method for proteomic analysis, but is notoriously difficult to reproduce between laboratories. We therefore describe methods which have been developed as standard operating procedures in our laboratory to ensure the reproducibility of proteomic analyses of wheat using 2D PAGE analysis of grain proteins.

Lovegrove, Alison; Salt, Louise; Shewry, Peter R.

242

Effects of the $\\gamma-$rays Scattered Backward by Metals on the Nuclear Energy Level Width  

CERN Document Server

By placing a ${}^{133}Cs$ $\\gamma$-ray source embedded in a solid at the center of a platinum (gold) cylinder, we try to change the width of the 81-keV level. Our results show a narrowed energy level and, equivalently, a prolonged lifetime. With a 0.5-mm-thick, 5-cm-long, 2-mm-diameter platinum cylinder, we obtain a width narrower by $6.1 % $ at $4.2 \\: K$.

Cheon, I T; Cheon, Il-Tong; Jeong, Moon Taeg

2006-01-01

243

Spreading width of giant resonances and the attenuation of zero sound  

International Nuclear Information System (INIS)

It is shown that the RPA plus perturbation approach which is commonly used to calculate microscopically the spreading width of Giant Resonances is equivalent to Landau's suggestion that the damping width of zero sound at temperature T=O can be obtained by multiplying the classical collision result with an energy ?- and T-dependent correction factor [1+(?/2?kT)_2] with T->O. (orig.)

1983-03-01

244

Escape- and Spreading Width of the Isobaric Analog State.  

Science.gov (United States)

Data and systematics on the natural line width, the escape width, and the spreading width of ground state isobaric analog states are presented. The relation between isospin impurity and spreading width, and between escape width and neutron spectroscopic f...

S. Y. Vanderwerf

1991-01-01

245

Resonance width distribution for open quantum systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recent measurements of resonance widths for low-energy neutron scattering off heavy nuclei show large deviations from the standard Porter-Thomas distribution. We propose a new resonance width distribution based on the random matrix theory for an open quantum system. Two methods of derivation lead to a single analytical expression; in the limit of vanishing continuum coupling, we recover the Porter-Thomas distribution. The result depends on the ratio of typical widths $\\Gamma...

Shchedrin, Gavriil; Zelevinsky, Vladimir

2011-01-01

246

Hadronic width of the ?b states  

International Nuclear Information System (INIS)

The CUSB-II Collaboration has inferred the hadronic widths of the ?b(2PJ) states from the measured branching fractions and the potential model rates of their E1 decays. These widths agree qualitatively with perturbative QCD calculations. The disagreement in absolute values of the widths between the experimental and QCD predictions confirm the same situation as in the charmonium system, which means more precision measurements are sorely needed. (author). 12 refs., 2 tabs

1994-01-01

247

The width of 5-dimensional prismatoids  

CERN Multimedia

Santos' construction of counter-examples to the Hirsch conjecture is based on the existence of prismatoids of dimension d of width greater than d. The case d=5 being the smallest one in which this can possibly occur, we here study the width of 5-dimensional prismatoids, obtaining the following results: - There are 5-prismatoids of width six with only 25 vertices, versus the 48 vertices in Santos' original construction. This leads to lowering the dimension of the non-Hirsch polytopes from 43 to only 20. - There are 5-prismatoids with n vertices and width \\Omega(n^(1/2)) for arbitrarily large n.

Matschke, Benjamin; Weibel, Christophe

2012-01-01

248

Approximation Algorithms for Directed Width Parameters  

CERN Document Server

Treewidth of an undirected graph measures how close the graph is to being a tree. Several problems that are NP-hard on general graphs are solvable in polynomial time on graphs with bounded treewidth. Motivated by the success of treewidth, several directed analogues of treewidth have been introduced to measure the similarity of a directed graph to a directed acyclic graph (DAG). Directed treewidth, D-width, DAG-width, Kelly-width and directed pathwidth are some such parameters. In this paper, we present the first approximation algorithms for all these five directed width parameters. For directed treewidth and D-width we achieve an approximation factor of O(sqrt{logn}). For DAG-width, Kelly-width and directed pathwidth we achieve an O({\\log}^{3/2}{n}) approximation factor. Our algorithms are constructive, i.e., they construct the decompositions associated with these parameters. The width of these decompositions are within the above mentioned factor of the corresponding optimal width.

Kintali, Shiva; Kumar, Akash

2011-01-01

249

The effect of change in width on stress distribution along the curved segments of stents  

International Nuclear Information System (INIS)

Curved structural members are widely seen in our surroundings, such as railway supports in playgrounds resembling a c-ring structure. The common geometry of the curved member consists of a segment of a circular ring with a uniform width. The curved section is of constant width in most cardiovascular stents. This study focuses on curved strut members whose width changes along the curved segment. The location of the maximum equivalent stress varies depending on the manner in which the width changes. When the width is constant or larger toward the top, the maximum equivalent stress is developed at the top. Meanwhile, when the area is reduced toward the bottom, the largest equivalent stress is developed some distance from the top. Simple equations, based on the mechanics of materials and the theory of elasticity, were compared favorably with the results from finite element analysis. Included are elaborations of the distribution of the change of stress. The suggested strategy of changing the width, with refinements, could be applied to the optimal design of structural members, including pipes and medical devices such as stents

2010-06-01

250

Program Equivalence in Linear Contexts  

CERN Multimedia

Program equivalence in linear contexts, where programs are used or executed exactly once, is an important issue in programming languages. However, existing techniques like those based on bisimulations and logical relations only target at contextual equivalence in the usual (non-linear) functional languages, and fail in capturing non-trivial equivalent programs in linear contexts, particularly when non-determinism is present. We propose the notion of linear contextual equivalence to formally characterize such program equivalence, as well as a novel and general approach to studying it in higher-order languages, based on labeled transition systems specifically designed for functional languages. We show that linear contextual equivalence indeed coincides with trace equivalence - it is sound and complete. We illustrate our technique in both deterministic (a linear version of PCF) and non-deterministic (linear PCF in Moggi's framework) functional languages.

Deng, Yuxin

2011-01-01

251

Neural Networks with Finite Width Action Potentials  

CERN Document Server

The significance of having finite widths of action potentials in integrate and fire neural networks is investigated. Models suggested by Hopfield and Herz [1] with zero action potential has been generalized to include pulse shapes of arbitrary widths and shapes. The convergence to limit cycle is examined both analytically and in simulation experiments. Hopfield's proof for nonleaking models has been extended nontrivially to the case of finite widths. It is pointed out that the concept of simultaneity in such networks maybe subject to bin widths in simulation experiments. The effects of varying the shape of the action potential and its width are examined. The roles of the magnitude of a leaking resistance connected to the neurons, a common external current and synaptic currents between neighbors are also examined and found to bear important consequences to the dynamical development of the network.

Shafee, F

2001-01-01

252

An HNCO-based Pulse Scheme for the Measurement of 13C{alpha}-1H{alpha} One-bond Dipolar couplings in 15N, 13C Labeled Proteins  

Energy Technology Data Exchange (ETDEWEB)

A triple resonance pulse scheme is presented for recording 13C{alpha}-1H{alpha} one-bond dipolar couplings in 15N, 13C labeled proteins. HNCO correlation maps are generated where the carbonyl chemical shift is modulated by the 13C{alpha}-1H{alpha} coupling, with the two doublet components separated into individual data sets. The experiment makes use of recently described methodology whereby the protein of interest is dissolved in a dilute solution of bicelles which orient above a critical temperature, thus permitting measurement of significant couplings (Tjandra and Bax, 1997a). An application to the protein ubiquitin is described.

Yang Daiwen; Tolman, Joel R. [University of Toronto, The Protein Engineering Centers of Excellence and Departments of Medical Genetics, Biochemistry and Chemistry (Canada); Goto, Natalie K. [University of Toronto, Department of Biochemistry (Canada); Kay, Lewis E. [University of Toronto, The Protein Engineering Centers of Excellence and Departments of Medical Genetics, Biochemistry and Chemistry (Canada)

1998-08-15

253

Electroweak Cross-sections and Widths  

Energy Technology Data Exchange (ETDEWEB)

The status of W and Z cross-section and width measurements from the CDF and D0 experiments is reviewed. Recent results that are discussed: the cross-section for Z production times the branching ratio to tau pairs, the rapidity and transverse momentum distributions of Z production in the electron channel, and the direct measurements of the W width and the Z invisible width; the latter from an analysis of events with large missing transverse energy and one or more energetic jets.

Robson, Aidan; /Glasgow U.

2008-10-01

254

Electroweak Cross-sections and Widths  

International Nuclear Information System (INIS)

The status of W and Z cross-section and width measurements from the CDF and D0 experiments is reviewed. Recent results that are discussed: the cross-section for Z production times the branching ratio to tau pairs, the rapidity and transverse momentum distributions of Z production in the electron channel, and the direct measurements of the W width and the Z invisible width; the latter from an analysis of events with large missing transverse energy and one or more energetic jets

2008-08-05

255

Infinite-dimensional generalization of Kolmogorov widths  

CERN Document Server

Recently the theory of widths of Kolmogorov-Gelfand has received a great deal of interest due to its close relationship with the newly born area of Compressive Sensing in Signal Processing. However fundamental problems of the theory of widths in multidimensional Theory of Functions remain untouched, as well as analogous problems in the theory of multidimensional Signal Analysis. In the present paper we provide a multidimensional generalization of the original result of Kolmogorov about the widths of an "ellipsoidal sets" consisting of functions defined on an interval.

Kounchev, Ognyan

2011-01-01

256

Testing Model Nesting and Equivalence  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Using existing technology, it can be hard or impossible to determine whether two structural equation models that are being considered may be nested. There is also no routine technology for evaluating whether two very different structural models may be equivalent. A simple nesting and equivalence testing (NET) procedure is proposed that uses random sample and model-reproduced moment matrices to evaluate both model nesting and equivalence. The analysis is “local” rather than “global” in...

Bentler, Peter M.; Satorra, Albert

2010-01-01

257

Logic Petri Nets and Equivalency  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Logic Petri nets (LPN) can describe and analyze batch processing function and passing value indeterminacy in cooperative systems and its practical applications are shown with some nontrivial examples. This study focuses on the analysis of the modeling power of LPNs and the equivalency between LPNs and Petri nets with inhibitor arcs (IPN). The equivalency is proved formally and a constructing algorithm of equivalent IPNs from LPNs is proposed based on the disjunctive normal forms of logi...

Du, Y. Y.; Guo, B. Q.

2009-01-01

258

Estimating equivalence with quantile regression  

Science.gov (United States)

Equivalence testing and corresponding confidence interval estimates are used to provide more enlightened statistical statements about parameter estimates by relating them to intervals of effect sizes deemed to be of scientific or practical importance rather than just to an effect size of zero. Equivalence tests and confidence interval estimates are based on a null hypothesis that a parameter estimate is either outside (inequivalence hypothesis) or inside (equivalence hypothesis) an equivalence region, depending on the question of interest and assignment of risk. The former approach, often referred to as bioequivalence testing, is often used in regulatory settings because it reverses the burden of proof compared to a standard test of significance, following a precautionary principle for environmental protection. Unfortunately, many applications of equivalence testing focus on establishing average equivalence by estimating differences in means of distributions that do not have homogeneous variances. I discuss how to compare equivalence across quantiles of distributions using confidence intervals on quantile regression estimates that detect differences in heterogeneous distributions missed by focusing on means. I used one-tailed confidence intervals based on inequivalence hypotheses in a two-group treatment-control design for estimating bioequivalence of arsenic concentrations in soils at an old ammunition testing site and bioequivalence of vegetation biomass at a reclaimed mining site. Two-tailed confidence intervals based both on inequivalence and equivalence hypotheses were used to examine quantile equivalence for negligible trends over time for a continuous exponential model of amphibian abundance. ?? 2011 by the Ecological Society of America.

Cade, B. S.

2011-01-01

259

Logic Petri Nets and Equivalency  

Directory of Open Access Journals (Sweden)

Full Text Available Logic Petri nets (LPN can describe and analyze batch processing function and passing value indeterminacy in cooperative systems and its practical applications are shown with some nontrivial examples. This study focuses on the analysis of the modeling power of LPNs and the equivalency between LPNs and Petri nets with inhibitor arcs (IPN. The equivalency is proved formally and a constructing algorithm of equivalent IPNs from LPNs is proposed based on the disjunctive normal forms of logic input/output expressions. Moreover, the size of an LPN model is smaller than that of the equivalent IPN model.

Y.Y. Du

2009-01-01

260

Ambient dose equivalent and directional dose equivalent instruments  

International Nuclear Information System (INIS)

According to definitions of the new operational radiation quantities for environmental (area) monitoring recommended by the International Commission of Radiation Units and Measurements (ICRU) report 39, a spherical ambient dose equivalent meter and a parallel-plane directional dose equivalent meter were designed and developed. Experimental measurements for main performances and calibrations for response factors were made

1991-01-01

 
 
 
 
261

The widths of magnetic twist modes  

International Nuclear Information System (INIS)

Within the dissipative nuclear fluid-dynamics the predictions are presented for the widths of magnetic twist resonances associated with the long wavelength torsion like vibrations of a spherical nucleus. 25 refs.; 2 figs.; 1 tab

1992-01-01

262

Neutron beam compressors for pulse width reduction  

International Nuclear Information System (INIS)

In the context of intensity and resolution optimization of a neutron time-of-flight spectrometer several methods of beam width reduction at the chopper are considered aiming at a reduction of the neutron pulse width at minimum loss of intensity. The most advantageous technique discussed uses a double-trumpet arrangement in which the chopper is placed in between converging and diverging neutron guide sections. 7 refs., 1 fig

1989-03-01

263

Rho decay width from the lattice  

CERN Document Server

While the masses of light hadrons have been extensively studied in lattice QCD simulations, there exist only a few exploratory calculations of the strong decay widths of hadronic resonances. We will present preliminary results of a computation of the rho meson width obtained using $N_f=2+1$ flavor simulations. The work is based on L\\"uscher's formalism and its extension to moving frames.

Frison, J; Fodor, Z; Hoelbling, C; Katz, S D; Krieg, S; Kurth, T; Lellouch, L; Lippert, T; Portelli, A; Ramos, A; Szabo, K K

2010-01-01

264

Equivalence between therm and gravity  

CERN Multimedia

We introduce the notion of thermal entropy density, and first demonstrated that there exists an equivalence between therm and gravity without depending on the definition of temperature or horizon. This equivalence indicates that gravity possesses thermal features, or, therm possesses effects of gravity. This may shed light on the nature of gravity.

Yang, Rong-Jia

2011-01-01

265

Large Nc equivalence and baryons  

Science.gov (United States)

In the large Nc limit, gauge theories with different gauge groups and matter content sometimes turn out to be “large Nc equivalent,” in the sense of having a set of coincident correlation functions. Large Nc equivalence has mainly been explored in the glueball and meson sectors. However, a recent proposal to dodge the fermion sign problem of QCD with a quark number chemical potential using large Nc equivalence motivates investigating the applicability of large Nc equivalence to correlation functions involving baryon operators. Here we present evidence that large Nc equivalence extends to the baryon sector, under the same type of symmetry realization assumptions as in the meson sector, by adapting the classic Witten analysis of large Nc baryons.

Blake, Mike; Cherman, Aleksey

2012-09-01

266

Appropriate energy window width for gamma camera  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Scatter radiation is one of the major sources of error in nuclear medicine data processing. Different methods of scatter correction have been introduced in order to improve the quality of data. However the best method is to avoid recording of scatter photons in acquisition. The only difference between scattered and non-scattered photons is the energy. Pulse height analyzer is the only option available to discriminate primary photons from scattered ones. Energy resolution of the gamma camera is gradually improving consequently the energy window width has to be decreased accordingly. In this study we tried to determine the most appropriate energy window width for present gamma camera systems. Methods and Materials: Since it is not possible to retrieve the data spectrum from the most of the gamma camera systems, a simple method was developed to extract the data from the image of the energy spectrum. Using a scatter phantom different level of scatter and count rate were generated and corresponding energy spectrum data were analyzed. It was assumed that around the peak of the spectrum, the primary photons obey a Gaussian distribution. Results: The data were analyzed using three different methods. All methods prove that the optimum window width regarding the present gamma camera energy resolution is 15%. At this level, the scattered radiation is decreased to 5%. In comparison to the conventional widow width of 20%, the sensitivity does not change dramatically. Conclusion: At the present, for most gamma camera, the energy window width of 20% is recommended. However occasionally energy window width of 15% and 25% are also used. In this study the energy spectrum at different levels of scatter were analyzed and the most suitable energy window width was found to be 15% for the gamma camera having approximate energy resolution of 11%. At this window setting the scatter decreases to 5% of the total counts recorded. Visually the quality of the images dose not improves significantly. However accuracy of data quantification improve significantly.

Jabbari N

2004-06-01

267

Spiral inflow feeding the nuclear starburst in M83, observed in H-alpha emission with the GHAFAS Fabry-Perot interferometer  

CERN Document Server

We present observations of the nearby barred starburst galaxy, M83 (NGC5236), with the new Fabry-Perot interferometer GHAFAS mounted on the 4.2 meter William Herschel Telescope on La Palma. The unprecedented high resolution observations, of 16 pc/FWHM, of the H-alpha-emitting gas cover the central two kpc of the galaxy. The velocity field displays the dominant disk rotation with signatures of gas inflow from kpc scales down to the nuclear regions. At the inner Inner Lindblad Resonance radius of the main bar and centerd at the dynamical center of the main galaxy disk, a nuclear $5.5 (\\pm 0.9) \\times 10^8 M_\\odot$ rapidly rotating disk with scale length of $60 \\pm 20$ pc has formed. The nuclear starburst is found in the vicinity as well as inside this nuclear disk, and our observations confirm that gas spirals in from the outer parts to feed the nuclear starburst, giving rise to several star formation events at different epochs, within the central 100 pc radius of M83.

Fathi, Kambiz; Lundgren, Andreas A; Carignan, Claude; Hernandez, Olivier; Amram, Philippe; Balard, Philippe; Boulesteix, Jacques; Gach, Jean-Luc; Knapen, Johan H; Relaño, Monica

2007-01-01

268

Study of LINER sources with broad H(alpha) emission. X-ray properties and comparision to luminous AGN and X-ray binaries  

CERN Document Server

[Abridged]We study the X-ray properties of LINER sources with definite detection of a broad H(alpha) emission line in their optical spectra, LINER 1s from Ho et al. sample. These objects preferentially harbor a low luminosity active nucleus at the center and show small or no intrinsic absorption (<10^(22) cm^(-1)). We analyzed all available X-ray archived XMM-Newton and Chandra observations of 13 LINER 1s satisfying the above criterion in a systematic homogeneous way. We looked for any correlations between the X-ray properties and the intrinsic parameters of our sample of LINER 1s. An absorbed power-law gave a good fit to the spectra of 9 out of the 13 sources. A thermal component and an absorbed power-law were required in the remaining 4 sources. We found a photon index between 1.3\\pm0.2 for the hardest source and 2.4^(+0.2)_(-0.3) for the softest one with a mean value of 1.9\\pm0.2 and a dispersion sigma=0.3. The thermal component had a mean temperature kT~0.6 keV. Significant short (hours to days) time-s...

George, Younes; Sabra, B; Reeves, J N

2011-01-01

269

The dynamics of z=0.8 H-alpha-selected star-forming galaxies from KMOS/CF-HiZELS  

CERN Document Server

We present the spatially resolved H-alpha (Ha) dynamics of sixteen star-forming galaxies at z~0.81 using the new KMOS multi-object integral field spectrograph on the ESO VLT. These galaxies were selected using 1.18 um narrow-band imaging from the 10 deg^2 CFHT-HiZELS survey of the SA22hr field, are found in a ~4Mpc over-density of Ha emitters and likely reside in a group/intermediate environment, but not a cluster. We confirm and identify a rich group of star-forming galaxies at z=0.813+-0.003, with thirteen galaxies within 1000 km/s of each other, and 7 within a diameter of 3Mpc. All our galaxies are "typical" star-forming galaxies at their redshift, 0.8+-0.4 SFR*(z=0.8), spanning a range of specific star formation rate of sSFR=0.2-1.1 Gyr^-1 and have a median metallicity very close to solar of 12+log(O/H)=8.62+-0.06. We measure the spatially resolved Ha dynamics of the galaxies in our sample and show that thirteen out of sixteen galaxies can be described by rotating disks and use the data to derive inclinat...

Sobral, David; Stott, John; Matthee, Jorryt; Bower, Richard G; Smail, Ian; Best, Philip N; Geach, James E; Sharples, Ray M

2013-01-01

270

A Survey of Local Group Galaxies Currently Forming Stars: III. A Search for Luminous Blue Variables and Other H-alpha Emission-Lined Stars  

CERN Document Server

We describe a search for H-alpha emission-lined stars in M31, M33, and seven dwarfs in or near the Local Group (IC 10, NGC 6822, WLM, Sextans B, Sextans A, Pegasus and the Phoenix dwarf) using interference filter imaging with the KPNO and CTIO 4-m telescope and Mosaic cameras. The survey is aimed primarily at identifying new Luminous Blue Variables (LBVs) from their spectroscopic similarity to known LBVs, avoiding the bias towards photometric variability, which may require centuries to manifest itself if LBVs go through long quiescent periods. Followup spectroscopy with WIYN confirms that our survey detected a wealth of stars whose spectra are similar to the known LBVs. We "classify" the spectra of known LBVs, and compare these to the spectra of the new LBV candidates. We demonstrate spectacular spectral variability for several of the new LBV candidates, such as AM2, previously classified as a Wolf-Rayet star, which now shows FeI, FeII and Balmer emission lines but neither the NIII 4634,42 nor HeII 4686 emiss...

Massey, Philip; Olsen, K A G; Hodge, Paul W; Blaha, Cynthia; Jacoby, George H; Smith, R C; Strong, Shay B

2007-01-01

271

The Masses of Distant Galaxies from Optical Emission Line Widths  

CERN Multimedia

Promising methods for studying galaxy evolution rely on optical emission line width measurements to compare intermediate-redshift objects to galaxies with equivalent masses at the present epoch. However, emission lines can be misleading. We show empirical examples of galaxies with concentrated central star formation from a survey of galaxies in pairs; HI observations of these galaxies indicate that the optical line emission fails to sample their full gravitational potentials. We use simple models of bulge-forming bursts of star formation to demonstrate that compact optical morphologies and small half-light radii can accompany these anomalously narrow emission lines; thus late-type bulges forming on rapid (0.5-1 Gyr) timescales at intermediate redshift would exhibit properties similar to those of heavily bursting dwarfs. We conclude that some of the luminous compact objects observed at intermediate and high redshift may be starbursts in the centers of massive galaxies and/or bulges in formation.

Gillespie, E B; Gillespie, Elizabeth Barton; Zee, Liese van

2002-01-01

272

What is correct: equivalent dose or dose equivalent  

International Nuclear Information System (INIS)

In Croatian language some physical quantities in radiation protection dosimetry have not precise names. Consequently, in practice either terms in English or mathematical formulas are used. The situation is even worse since the Croatian language only a limited number of textbooks, reference books and other papers are available. This paper compares the concept of ''dose equivalent'' as outlined in International Commission on Radiological Protection (ICRP) recommendations No. 26 and newest, conceptually different concept of ''equivalent dose'' which is introduced in ICRP 60. It was found out that Croatian terminology is both not uniform and unprecise. For the term ''dose equivalent'' was, under influence of Russian and Serbian languages, often used as term ''equivalent dose'' even from the point of view of ICRP 26 recommendations, which was not justified. Unfortunately, even now, in Croatia the legal unit still ''dose equivalent'' defined as in ICRP 26, but the term used for it is ''equivalent dose''. Therefore, in Croatian legislation a modified set of quantities introduced in ICRP 60, should be incorporated as soon as possible

1994-11-23

273

Monteggia Type IV Equivalent Injury  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Equivalent lesions of Monteggia type IV injury have not appeared so far in the literature. Two Monteggia type IV equivalent lesions, which included a fracture of the radial head associated with midshaft fractures of the radius and ulna in a 3- and in a 12-year-old girl, are reported. The lesion presented in this report could be considered as a missing piece in the puzzle of Monteggia and equivalent injuries, and it could also add towards considering type IV injury as a primary lesion and not ...

Sferopoulos, Nikolaos K.

2011-01-01

274

Some properties of the width fluctuation factor  

International Nuclear Information System (INIS)

The subject of width fluctuation correction to average compound-nucleus cross sections is reviewed, with special emphasis on neutron capture and scattering cross sections. Recent statistical model theories on the calculation of cross sections offer a new approach to the calculation of this correction factor. For low energies, the classical integration method gives the best description. At higher energies, the approximation of Tepel et al. with a semi-empirical relation for the elastic enhancement parameter is recommended for practical calculations. In the discussion about properties of the width fluctuation factor (WFF), the concept of a lumped channel with an effective number of degrees of freedom, v/sub eff/, has proven to be helpful. A new definition of v/sub eff/ is given. Under certain conditions, the WFF for nonelastic processes can become larger than unity. Some other examples of width fluctuation effects are given for neutron elastic and inelastic scattering

1977-01-01

275

Alliances and Bisection Width for Planar Graphs  

DEFF Research Database (Denmark)

An alliance in a graph is a set of vertices (allies) such that each vertex in the alliance has at least as many allies (counting the vertex itself) as non-allies in its neighborhood of the graph. We show that any planar graph with minimum degree at least 4 can be split into two alliances in polynomial time. We base this on a proof of an upper bound of n on the bisection width for 4-connected planar graphs with an odd number of vertices. This improves a recently published nâ??+â??1 upper bound on the bisection width of planar graphs without separating triangles and supports the folklore conjecture that a general upper bound of n exists for the bisection width of planar graphs.

Olsen, Martin; Revsbæk, Morten

2013-01-01

276

Constraints on widths of mixed pentaquark multiplets  

CERN Multimedia

We determine constraints on the partial widths of mixed pentaquark multiplets in the framework of heavy baryon chiral perturbation theory (HB$\\chi$PT). The partial widths satisfy a GMO-type relation at leading order in HB$\\chi$PT, for arbitrary mixing. The widths of N(1440), N(1710), and $\\Theta(1540)$ are not consistent with ideal mixing, $\\theta_{N} = 35.3^{\\circ}$, but are consistent with $\\theta_{N} \\lesssim 25^{\\circ}$. Furthermore, there are parameter values in HB$\\chi$PT that produce such a mixing angle while allowing the identification of the mass spectrum above. As an alternative to non-ideal mixing, we also suggest reasons for giving up on N(1440) as a pure pentaquark state.

Mohta, V

2004-01-01

277

Pulse Width in a Rod Ejection Accident  

International Nuclear Information System (INIS)

An analysis of pulse width during a rod ejection accident was carried out to help in designing experiments to test fuel behaviour under reactivity initiated accident conditions. The analysis used calculations based on a three-dimensional neutron kinetics code, PARCS, and a model of a pressurized water reactor at both beginning and end of a fuel cycle. Results showed that pulse width varied inversely with the maximum increase in local fuel enthalpy and this is consistent with simple analytical models. The pulse width ranges from 25 to 100 ms for cases where the energy deposition goes from 30 to 10 cal/g. This is the range expected for the most likely REA for which the rod worth is just above prompt critical. It is the most likely REA since the probability of a particular rod worth decreases as one goes to higher rod worths above prompt-critical. The pulse width is 10-15 ms when the maximum increase in fuel enthalpy is in the range of 60-100 cal/g. It is at these enthalpies, or higher, where fuel failure might be expected. Hence, if tests are to be done to test the limits of a fuel pin, the pulse width in the tests should be in the range 10-15 ms. If the tests instead are done with pulse widths that are greater than 25 ms and fuel enthalpies that are in the range where failure is expected, e.g., 100 cal/g, there is an inconsistency

2003-04-30

278

Width of l^p balls  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We say a map f:X \\to Y is an \\epsilon-embedding if it is continuous and the diameter of the fibres is less than \\epsilon. This type of maps is used in the notion of Urysohn width (sometimes referred to as Alexandrov width), a_n(X). It is the smallest real number such that there exists an \\epsilon-embedding from X to a n-dimensional polyhedron. Surprisingly few estimations of these numbers can be found, and one of the aims of this paper is to present some. Following Gromov, we take the slightl...

Gournay, Antoine

2007-01-01

279

The width difference of rho vector mesons  

CERN Multimedia

We compute the difference in decay widths of charged and neutral \\rho(770) vector mesons. The isospin breaking arising from mass differences of neutral and charged \\pi and \\rho mesons, radiative corrections to \\rho -> \\pi\\pi, and the \\rho -> \\pi\\pi\\gamma decays are taken into account. It is found that the width difference \\Delta \\Gamma_rho is very sensitive ot the isospin breaking in the $\\rho$ meson mass \\Delta m_\\rho. This result can be useful to test the correlations observed between the values of these parameters extracted from experimental data.

Flores-Baez, F V; Sanchez, G Toledo

2007-01-01

280

High Fin Width Mosfet Using Gaa Structure  

Directory of Open Access Journals (Sweden)

Full Text Available This paper describes the design and optimization of gate-all-around (GAA MOSFETs structures. The optimum value of Fin width and Fin height are investigated for superior subthreshold behavior. Also the performance of Fin shaped GAA with gate oxide HfO2 are simulated and compared with conventional gate oxide SiO2 for the same structure. As a result, it was observed that the GAA with high K dielectric gate oxide has more possibility to optimize the Fin width with improved performance. All the simulations are performed on 3-D TCAD device simulator.

S.L.Tripathi

2012-11-01

 
 
 
 
281

Tissue Engineered Human Skin Equivalents  

Directory of Open Access Journals (Sweden)

Full Text Available Human skin not only serves as an important barrier against the penetration of exogenous substances into the body, but also provides a potential avenue for the transport of functional active drugs/reagents/ingredients into the skin (topical delivery and/or the body (transdermal delivery. In the past three decades, research and development in human skin equivalents have advanced in parallel with those in tissue engineering and regenerative medicine. The human skin equivalents are used commercially as clinical skin substitutes and as models for permeation and toxicity screening. Several academic laboratories have developed their own human skin equivalent models and applied these models for studying skin permeation, corrosivity and irritation, compound toxicity, biochemistry, metabolism and cellular pharmacology. Various aspects of the state of the art of human skin equivalents are reviewed and discussed.

Zheng Zhang

2012-01-01

282

Influence of film width and magnetic field orientation on AC loss in YBCO thin film  

International Nuclear Information System (INIS)

Three YBCO thin films on sapphire substrate with widths of 3, 5, and 10 mm were prepared, and their AC loss characteristics were studied experimentally. The total AC loss dissipated in samples carrying AC transport current in an AC transverse magnetic field was measured by an electromagnetic method. The total AC loss in YBCO film is proportional to the film width and the perpendicular magnetic field component, a component of the transverse magnetic field that is perpendicular to the film wide face. Reduction of the film width and/or the perpendicular magnetic field component is an essential means of decreasing the total AC loss. When plotting the total AC loss divided by film width against the perpendicular magnetic field component, curves for various film widths and field angles almost agree with each other. The total AC loss can be estimated by analytical expressions except in an intermediate range of the perpendicular magnetic field component. The experimental results indicate two engineering approaches for reducing the total AC loss in YBCO film: decreasing the film width and decreasing the perpendicular magnetic field component. Findings have shown empirically that decreasing the film width and decreasing sin?, where ? is the field angle, are equivalently effective in reducing the total AC loss

2004-03-01

283

A Window Width Optimized S-Transform  

Directory of Open Access Journals (Sweden)

Full Text Available Energy concentration of the S-transform in the time-frequency domain has been addressed in this paper by optimizing the width of the window function used. A new scheme is developed and referred to as a window width optimized S-transform. Two optimization schemes have been proposed, one for a constant window width, the other for time-varying window width. The former is intended for signals with constant or slowly varying frequencies, while the latter can deal with signals with fast changing frequency components. The proposed scheme has been evaluated using a set of test signals. The results have indicated that the new scheme can provide much improved energy concentration in the time-frequency domain in comparison with the standard S-transform. It is also shown using the test signals that the proposed scheme can lead to higher energy concentration in comparison with other standard linear techniques, such as short-time Fourier transform and its adaptive forms. Finally, the method has been demonstrated on engine knock signal analysis to show its effectiveness.

Jin Jiang

2008-02-01

284

Nonlocal potentials and resonances of narrow width  

International Nuclear Information System (INIS)

This paper discusses resonances of narrow width in the context of bound states embedded in the continuum spectrum of nonlocal potentials. Feshbach's theory of nuclear reactions leads directly to resonance theory, and we base our discussion here on the techniques he developed for shifting nuclear many-body aspects into effective single-particle nonlocal potentials. In our formulation, the many-body state of the compound nucleus is represented by a single-particle state. The basis for our discussion is a two channel model of a resonance of zero width, with a continuum bound state originating from the coupling of a bound state to the single-particle scattering state. We give a specific example of a model which leads to an arbitrarily narrow (nonzero width) resonance, and demonstrate that the width of the resonance produced by breaking the continuum bound state is proportional to (?-1)2, where the parameter ? is such that ? = 1 corresponds to the condition necessary for the existence of a continuum bound state

1982-01-01

285

The ratio of the interzygomatic width with mesiodistal width of maxillary anterior teeth  

Directory of Open Access Journals (Sweden)

Full Text Available Esthetics is one of the prosthetic treatment goals. Correct selection of anterior teeth, regarding size and appearance, results in a successful treatment. The goal of the present research was to investigate the relationship between interzygomatic width and maxillary anterior teeth width in order to find a better determinant for artificial anterior teeth selection. In this study, the interzygomatic width and maxillary central incisors width and also the width of six maxillary anterior- teeth, in 71 subjects (29females and 42 males were measured. The results showed a significant difference in maxillary anterior teeth width, comparing men and women, (P<0.05. These measurement in people under study, are less than Europeans. The interzygomatic width was also more in men than women (PO.05, which is, less than of European race. The ratio between interzygomatic and central maxillary incisor width was 15:1 which is less than 16:1 that is used in clinic. Thus, it is recommended to pay more attention to anterior teeth selection, especially in young patients.

Savabi O

2002-07-01

286

Using tissue equivalent proportional counters to determine dose equivalent  

International Nuclear Information System (INIS)

Tissue equivalent proportional counters (TEPCs) have been used in the laboratory for over 30 years to determine neutron dose in mixed radiation fields, but they are seldom used by operational health physicists. But a number of TEPC-based instruments are being developed in Europe and in the United States. The purpose of this paper is: to introduce operational health physicists to tissue equivalent proportional counters, to examine some of the algorithms used to convert data from TEPCs into dose equivalent, to examine how TEPC measurements meet the requirements of DOE Order 5480.11 (DOE 1988) and 10CFR20, and to examine some of the TEPC-based instruments that are available. Many operational health physicists are not familiar with the concept of microdosimetry and the specialized terms that are used in analyzing the data from TEPCs, so a brief discussion is included. At present, quality factors are defined in terms of linear energy transfer, but TEPCs measure lineal energy

1991-06-04

287

A report on the introduction of ultrabrief pulse width ECT in a private psychiatric hospital.  

Science.gov (United States)

We report on 6 months of data since the introduction of ultrabrief pulse width electroconvulsive therapy (UB ECT) at a private psychiatric hospital in Adelaide. Results suggest that psychiatrists welcomed the availability of UB ECT, with an increase in prescription of ECT. About a quarter of UB ECT patients changed to standard pulse width (SPW) ECT, but those who did respond to UB ECT had an equivalent response to those who had SPW ECT. Courses of treatment were longer with UB ECT, which was reflected in an increased length of stay. PMID:22343583

Galletly, Cherrie; Paterson, Tom; Burton, Cassandra

2012-03-01

288

Equivalent damage: A critical assessment  

Science.gov (United States)

Concepts in equivalent damage were evaluated to determine their applicability to the life prediction of hot path components of aircraft gas turbine engines. Equivalent damage was defined as being those effects which influence the crack initiation life-time beyond the damage that is measured in uniaxial, fully-reversed sinusoidal and isothermal experiments at low homologous temperatures. Three areas of equivalent damage were examined: mean stress, cumulative damage, and multiaxiality. For each area, a literature survey was conducted to aid in selecting the most appropriate theories. Where possible, data correlations were also used in the evaluation process. A set of criteria was developed for ranking the theories in each equivalent damage regime. These criteria considered aspects of engine utilization as well as the theoretical basis and correlative ability of each theory. In addition, consideration was given to the complex nature of the loading cycle at fatigue critical locations of hot path components; this loading includes non-proportional multiaxial stressing, combined temperature and strain fluctuations, and general creep-fatigue interactions. Through applications of selected equivalent damage theories to some suitable data sets it was found that there is insufficient data to allow specific recommendations of preferred theories for general applications. A series of experiments and areas of further investigations were identified.

Laflen, J. R.; Cook, T. S.

1982-01-01

289

EQUIVALENCE VERSUS NON-EQUIVALENCE IN ECONOMIC TRANSLATION  

Directory of Open Access Journals (Sweden)

Full Text Available This paper aims at highlighting the fact that “equivalence” represents a concept worth revisiting and detailing upon when tackling the translation process of economic texts both from English into Romanian and from Romanian into English. Far from being exhaustive, our analysis will focus upon the problems arising from the lack of equivalence at the word level. Consequently, relevant examples from the economic field will be provided to account for the following types of non-equivalence at word level: culturespecific concepts; the source language concept is not lexicalised in the target language; the source language word is semantically complex; differences in physical and interpersonal perspective; differences in expressive meaning; differences in form; differences in frequency and purpose of using specific forms and the use of loan words in the source text. Likewise, we shall illustrate a number of translation strategies necessary to deal with the afore-mentioned cases of non-equivalence: translation by a more general word (superordinate; translation by a more neutral/less expressive word; translation by cultural substitution; translation using a loan word or loan word plus explanation; translation by paraphrase using a related word; translation by paraphrase using unrelated words; translation by omission and translation by illustration.

Cristina, Chifane

2012-01-01

290

Momentum Maps and Morita Equivalence  

CERN Multimedia

We introduce quasi-symplectic groupoids and explain their relation with momentum map theories. This approach enables us to unify into a single framework various momentum map theories, including the ordinary Hamiltonian $G$-spaces, Lu's momentum maps of Poisson group actions, and group valued momentum maps of Alekseev--Malkin--Meinrenken. More precisely, we carry out the following program: (1) Define and study properties of quasi-symplectic groupoids; (2) Study the momentum map theory defined by a quasi-symplectic groupoid. In particular, we study the reduction theory and prove that the reduced space is always a symplectic manifold. More generally, we prove that the classical intertwiner space between two Hamiltonian $\\Gamma$-spaces is always a symplectic manifold whenever it is a smooth manifold; (3) Study the Morita equivalence of quasi-symplectic groupoids. In particular, we prove that Morita equivalent quasi-symplectic groupoids give rise to equivalent momentum map theories and that the intertwiner space i...

Xu, P

2003-01-01

291

A new Beaufort equivalent scale  

International Nuclear Information System (INIS)

By comparing Beaufort estimates with simultaneous wind speed measurements the relationship between both parameters can be determined in form of a Beaufort equivalent scale. Previous equivalent scales were derived without regard to the fact, that the error variances of the basic observations are different. In most cases even the variance of only one parameter was minimized, either the variance of the Beaufort estimates or the variance of wind measurements. Such regression methods do not yield the universal relationship between both parameters, which is required for a Beaufort scale. Therefore a new Beaufort equivalent scale is derived by comparing the three-hourly wind speed measurements from six North Atlantic ocean weather stations between 1960 and 1971 with 228210 Beaufort estimates of passing merchant ships. (orig.)

1994-01-01

292

Exotic Meson Decay Widths using Lattice QCD  

CERN Multimedia

A decay width calculation for a hybrid exotic meson h, with JPC=1-+, is presented for the channel h->pi+a1. This quenched lattice QCD simulation employs Luescher's finite box method. Operators coupling to the h and pi+a1 states are used at various levels of smearing and fuzzing, and at four quark masses. Eigenvalues of the corresponding correlation matrices yield energy spectra that determine scattering phase shifts for a discrete set of relative pi+a1 momenta. Although the phase shift data is sparse, fits to a Breit-Wigner model are attempted, resulting in a decay width of about 60 MeV when averaged over two lattice sizes.

Cook, M S

2006-01-01

293

Numerical simulation of distorted crystal Darwin width  

International Nuclear Information System (INIS)

A new numerical simulation method according to distorted crystal optical theory was used to predict the direct-cooling crystal monochromator optical properties(crystal Darwin width) in this study. The finite element analysis software was used to calculate the deformed displacements of DCM crystal and to get the local reciprocal lattice vector of distorted crystal. The broadening of direct-cooling crystal Darwin width in meridional direction was estimated at 4.12 ?rad. The result agrees well with the experimental data of 5 ?rad, while it was 3.89 ?rad by traditional calculation method of root mean square (RMS) of the slope error in the center line of footprint. The new method provides important theoretical support for designing and processing of monochromator crystal for synchrotron radiation beamline. (authors)

2012-06-01

294

New physics basis for SOL width  

Science.gov (United States)

Existing empirical projection for SOL power width (projected from the divertor plate to the plasma midplane) have a very large uncertainty. Hence, the adequacy of required divertor operation on projected high power density devices (FDF, ST-CTF, Fusion Reactors, etc.) is highly uncertain. A simple general physical principle is presented which greatly reduces the uncertainty -- transport in the near-SOL cannot substantially differ from the immediately adjacent pedestal. This is motivated by a diverse class of experimental data and theoretical estimates, and unifies apparently different projection approaches. We quantitatively formulate this and test against several lines of experimental data with good agreement. Our predictions for ITER are is reasonable agreement with the 2007 ITER physics basis, and generally support the narrower range of projections for next generation devices. SOL widths are necessarily narrow if there is a good H-mode pedestal, i.e., good core confinement and challenging divertor operation are intrinsically intertwined.

Kotschenreuther, Mike; Valanju, Prashant; Mahajan, Swadesh

2008-11-01

295

CMS presents new boundary of Higgs width  

CERN Document Server

At last year's Moriond conference, CERN physicists announced the retirement of the "Higgs-like" particle and the arrival of "boson, Higgs boson". Now, one year later, at the same session in the same conference, physicists are back with more exciting news about the famed particle. This time: the best constraint yet of the Higgs Boson “width”, a parameter that determines the particle’s lifetime.   Rencontres de Moriond 2014. As a key indicator for new physics, the Higgs “width” has long been on the LHC "to-do" list. Now less than two years post-discovery, the CMS experiment has gotten the closest yet to pinning it down, constraining the parameter to < 17 MeV with 95% confidence. This result is some two orders of magnitude better than previous limits: stronger evidence that this boson looks like the Standard Model Higgs boson. "It's been exciting to see how wel...

Katarina Anthony

2014-01-01

296

Optical trail widths of faint meteors observed with the Canadian Automated Meteor Observatory  

Science.gov (United States)

The optical trail widths of 30 faint meteors (average magnitude ˜+3, m ˜ 10-4 kg) were resolved and measured using the Canadian Automated Meteor Observatory (CAMO). CAMO is an automated, high-resolution intensified digital video system capable of detecting meteors as faint as magnitude +5. The observatory's two stations, separated by a baseline of 50 km, and each comprised of a narrow- and wide-field camera, observed the meteors for this survey. Data from the wide-field cameras were used to derive a trajectory solution for each meteor with the software package METAL, while data from the narrow-field cameras were used to measure trail widths with the image analysis software IMAGEJ. Raw widths were measured as a function of distance along the meteor trail for each frame of the video. To ensure that instrumental bloom did not artificially increase trail widths, the width of a star imaged with the narrow-field camera, with equivalent brightness to the meteor trail at the point of measurement, was subtracted from each observed raw width. Corrected trail widths up to 100 m at heights above 110 km were observed, varying with height as the inverse of atmospheric density. 14 of the 30 events were observed with both narrow-field cameras and each showed good agreement of trail width values after bloom correction. This suggested that the widths were true physical sizes, and not instrumental artefacts. Preliminary investigation suggests collisional de-excitation of energetic atoms is a plausible process for the formation of these wide trails.

Stokan, E.; Campbell-Brown, M. D.; Brown, P. G.; Hawkes, R. L.; Doubova, M.; Weryk, R. J.

2013-08-01

297

Thurston equivalence of topological polynomials  

CERN Document Server

We answer Hubbard's question on determining the Thurston equivalence class of ``twisted rabbits'', i.e. images of the ``rabbit'' polynomial under n-th powers of the Dehn twists about its ears. The answer is expressed in terms of the 4-adic expansion of n. We also answer the equivalent question for the other two families of degree-2 topological polynomials with three post-critical points. In the process, we rephrase the questions in group-theoretical language, in terms of wreath recursions.

Bartholdi, L; Bartholdi, Laurent; Nekrashevych, Volodymyr

2005-01-01

298

LEP hadronic Z0 partial widths  

International Nuclear Information System (INIS)

The experimental situation on hadronic Z0 partial widths at LEP is reviewed. In the absence of recent results on light quarks, only new data concerning Z0 ? b b bar and Z0 ? cc bar are considered. A LEP average value of Rb (with a 1% precision) implying low top quark mass or new phenomena within the Standard Model framework is presented. A slight deviation of Rb from the Standard Model value is observed. 6 figs., 18 refs

1994-03-12

299

First Digit Distribution of Hadron Full Width  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A phenomenological law, called Benford's law, states that the occurrence of the first digit, i.e., $1,2,...,9$, of numbers from many real world sources is not uniformly distributed, but instead favors smaller ones according to a logarithmic distribution. We investigate, for the first time, the first digit distribution of the full widths of mesons and baryons in the well defined science domain of particle physics systematically, and find that they agree excellently with the B...

Shao, Lijing; Ma, Bo-qiang

2010-01-01

300

ECC water spreading width for flat plate  

International Nuclear Information System (INIS)

To investigate the characteristics of water jet spreading width induced by Direct Vessel Injection(DVI), a steady state and separate effect test focusing on the effect of the downcomer curvature was performed using a rectangular flat-plate air-water open channel test facility. Comparative tests using various scaled diameter(D) of water jet nozzle, channel gap(W), water jet velocity(VJET), and forced cross air-flow(Vc) on the water film are performed for the Korean Next Generation Reactor(KNGR) during the late reflood phase of LBLOCA. A simplified and visible thin acryl plates were used. The air-water channel has a nearly full height in height between DVI and coldleg. The channel gap and the diameter of water injection nozzle have scaled ratios of 1/50 ? 1/10 by volume scaling method. The cross flow is introduced in the airwater channel to investigate the cross flow effects on the ECC water jet spreading width. The major parameters measured in the experiments are the film width of ECC water, the shifted degree of water film boundary by the cross air flow, and the attachment liquid fraction to total injected water in the region of front plate against water injected wall plate. It was found out that (1) If the test scale is increased, for the typical film spreading width without any cross flow, the film width is linearly increased at the bottom of air-water channel except at the top of film. (2) If the cross flow is induced on the liquid film for the test scale of 1:51.68, the highly shifted film shape is formed (3) If the test scale and the water injection velocity are increased, the attachment ratio of liquid on the front plate is sharply increased. (4) The attachment ratio of liquid on the front plate is strongly increased by cross flow. In the case of 9.52 scaled test, the attachment ratio of liquid is affected by both the cross flow and the water injection velocity

2000-10-01

 
 
 
 
301

Equivalence theorem and infrared divergences  

International Nuclear Information System (INIS)

We look at the equivalence theorem as a statement about the absence of polynomial infrared divergences when mW?0. We prove their absence in a truncated toy model and conjecture that, if they exist at all, they are due to couplings between light particles. copyright 1996 The American Physical Society

1996-08-01

302

Equivalence theorem and infrared divergences  

Energy Technology Data Exchange (ETDEWEB)

We look at the equivalence theorem as a statement about the absence of polynomial infrared divergences when {ital m}{sub {ital W}}{r_arrow}0. We prove their absence in a truncated toy model and conjecture that, if they exist at all, they are due to couplings between light particles. {copyright} {ital 1996 The American Physical Society.}

Torma, T. [Department of Physics, LGRC 1129, University of Massachusetts, Amherst, Massachusetts 01003 (United States)

1996-08-01

303

Morita equivalence of inverse semigroups  

CERN Multimedia

We describe how to construct all inverse semigroups Morita equivalent to a given inverse semigroup. This is done by taking the maximum inverse images of the regular Rees matrix semigroups over the inverse semigroup where the sandwich matrix satisfies what we call the McAlister conditions.

Afara, B

2011-01-01

304

On the Einstein equivalence principle  

Energy Technology Data Exchange (ETDEWEB)

The Einstein equivalence principle, the cornerstone of our present day understanding of gravity, is used to explore a deeper connection between the deflection of starlight by a spinning object and the Lense-Thirring dragging of inertial frames. It is also noted that experiment has not established that the gravitomagnetic coupling to currents of particle rest-mass energy, to currents of electromagnetic energy, and to currents of all other types of energy are identical as predicted by the Einstein equivalence principle. The detailed analysis of how atomic physics experiments originated by Hughes and by Drever can constrain such possible violations of the Einstein equivalence principle is given. Atomic clocks are also important tools used to test local Lorentz invariance and hence one important aspect of Einstein equivalence principle. The sensitivity of atomic clocks to preferred-frame effects is studied here for the first time, and the behavior of the hydrogen-maser clocks of the Gravity Probe A experiment is analyzed to illustrate use of the techniques involved.

Gabriel, M.D.

1989-01-01

305

Width and partial widths of unstable particles in the light of the Nielsen identities  

International Nuclear Information System (INIS)

Fundamental properties of unstable particles, including mass, width, and partial widths, are examined on the basis of the Nielsen identities (NI) that describe the gauge dependence of Green functions. In particular, we prove that the pole residues and associated definitions of branching ratios and partial widths are gauge independent to all orders. A simpler, previously discussed definition of branching ratios and partial widths is found to be gauge independent through next-to-next-to-leading order. It is then explained how it may be modified in order to extend the gauge independence to all orders. We also show that the physical scattering amplitude is the most general combination of self-energy, vertex, and box contributions that is gauge independent for arbitrary s, discuss the analytical properties of the NI functions, and exhibit explicitly their one-loop expressions in the Z-? sector of the standard model

2002-04-15

306

Resolving single bubble sonoluminescence flask width  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Single bubble sonoluminescence (SBSL), first studied and observed by Gaitan et al., is the of light emission from a single gas bubble trapped at the pressure maximum of a resonant sound field in a liquid medium, generally water. One of the most striking aspects of SBSL was the estimated optical flash width being less than 50 picoseconds (ps)3; this upper estimate was based on the relative response of a SBSL flash in comparison to a 34 ps laser pulse using a microchannel platephotomultiplier ...

1998-01-01

307

Nuclear structure effects on alpha reduced widths  

Energy Technology Data Exchange (ETDEWEB)

A review of ..cap alpha.. widths for s-wave transitions is presented together with a discussion of the following topics: (1) a new determination of the /sup 218/Ra half-life and its relation to reflection asymmetry in nuclei near N = 130, (2) a measurement of the /sup 194/Pb ..cap alpha..-decay rate and the influence of the Z = 82 gap on neutron-deficient Pb nuclei, and (3) an up-date of ..cap alpha..-decay-rate systematics for isotopes in the rare earth and medium-weight mass regions. 16 refs., 6 figs.

Toth, K.S.; Ellis-Akovali, Y.A.; Kim, H.J.; McConnell, J.W.

1987-01-01

308

Nuclear structure effects on ? reduced widths  

International Nuclear Information System (INIS)

A review of ? widths for s-wave transitions is presented together with a discussion of the following topics: 1) a new determination of the /sup 218/Ra half-life and its relation to reflection asymmetry in nuclei near N = 130, 2) a measurement of the /sup 194/Pb ?-decay rate and the influence of the Z = 82 gap on neutron-deficient Pb nuclei and 3) an up-date of ?-decay-rate systematics for isotopes in the rare earth and medium-weight mass regions

1987-12-10

309

Simple method for calculating island widths  

Energy Technology Data Exchange (ETDEWEB)

A simple method for calculating magnetic island widths has been developed. This method uses only information obtained from integrating along the closed field line at the island center. Thus, this method is computationally less intensive than the usual method of producing surfaces of section of sufficient detail to locate and resolve the island separatrix. This method has been implemented numerically and used to analyze the buss work islands of ATF. In this case the method proves to be accurate to at least within 30%. 7 refs.

Cary, J.R.; Hanson, J.D.; Carreras, B.A.; Lynch, V.E.

1989-01-01

310

Constraining the divertor heat width in ITER  

Science.gov (United States)

A model is developed which constrains heat width, ?r based on global power balance, momentum conservation, pedestal stability and sheath heat transmission. The model relies on measurements of the ratio of separatrix to pedestal pressure; a ratio ˜5% is found to be expected for ITER. Applying this model indicates a constraint that the allowed ?r ˜ 10-30 mm for ITER if the divertor is in the high-recycling regime as expected (T 100 eV, a condition which would have very negative consequences for the divertor, but has never been observed experimentally.

Whyte, D. G.; LaBombard, B.; Hughes, J. W.; Lipschultz, B.; Terry, J.; Brunner, D.; Stangeby, P. C.; Elder, D.; Leonard, A. W.; Watkins, J.

2013-07-01

311

Effect of different Gaussian width on disappearance of flow  

CERN Document Server

In the present paper, we reduce and enhance the scaled Gaussian width(SGW) by 30% from the normal SGW of the systems and see its effect on balance energy. The scaled Gaussian width can be defined as the ratio of Gaussian width used for any nuclei to the Gaussian width used for Au nuclei(i.e. 8.66 $fm^2$).

Rajni,

2011-01-01

312

Equivalence relations among interconnection networks  

Energy Technology Data Exchange (ETDEWEB)

The paper presents several notions of relations, including group isomorphisms, among interconnection networks. Examples of these relations for a class of cube-connected networks are also provided. It is shown that any form of equivalence between two networks induced by a relabeling of the source nodes of either network is directly linked to the existence of a conjugation map between their sets of interconnections. In particular, it is demonstrated that for the cube-connected networks discussed, this map reduces to identity under individual stage control, implying an absolute equivalence among these networks. For those cube-connected networks which require nontrivial conjugation maps, a procedure for explicit construction of such maps is also provided.

Oruc, A.Y.; Oruc, M.Y.

1985-02-01

313

Locally potentially equivalent Galois representations  

CERN Document Server

We show that if two continuous semi-simple \\(\\ell \\)-adic Galois representations are locally potentially equivalent at a sufficiently large set of places then they are globaly potentially equivalent. We also prove an analogous result for arbitrarily varying powers of character values evaluated at the Frobenius conjugacy classes. In the context of modular forms, we prove: given two non-CM newforms $f$ and $g$ of weight at least two, such that $a_p(f)^{n_p}=a_p(g)^{n_p}$ on a set of primes of positive upper density and for some set of natural numbers $n_p$, then $f$ and $g$ are twists of each other by a Dirichlet character.

Patankar, Vijay M

2010-01-01

314

Equivalent circuit analysis of sled  

International Nuclear Information System (INIS)

A direct application of equivalent circuit concepts leads to: (1) confirmation of Perry Wilson's SLED (SLAC Linac Energy Doubler) equation; (2) an equation that applies to a SLED device with input and output waveguides of different characteristic impedances; and (3) an equation that results if we demand that no power be lost by reflection from SLED. If the incident voltage is tailored as prescribed by this equation, the cavity voltage tracks the incident voltage and the reflected voltage is zero

1986-01-01

315

Equivalences of higher derived brackets  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This note elaborates on Th. Voronov’s construction [Th. Voronov, Higher derived brackets and homotopy algebras, J. Pure Appl. Algebra 202 (1–3) (2005) 133–153; Th. Voronov, Higher derived brackets for arbitrary derivations, Travaux Math. XVI (2005) 163–186] of L?-structures via higher derived brackets with a Maurer–Cartan element. It is shown that gauge equivalent Maurer–Cartan elements induce L?-isomorphic structures. Applications in symplectic, Poisson and Dirac geometry are...

2008-01-01

316

Orbit equivalence and sofic approximation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Given an ergodic probability measure preserving dynamical system $\\G\\acts (X,\\mu)$, where $\\G$ is a finitely generated countable group, we show that the asymptotic growth of the number of finite models for the dynamics, in the sense of sofic approximations, is an invariant of orbit equivalence. We then prove an additivity formula for free products with amenable (possibly trivial) amalgamation. In particular, we obtain purely combinatorial proofs of several results in orbit e...

Dykema, Ken; Kerr, David; Pichot, Mikael

2011-01-01

317

The first measured Mn I Stark widths  

International Nuclear Information System (INIS)

The shapes of the astrophysically interesting neutral manganese (Mn I) resonance spectral lines (403.075, 403.306, 403.448, 279.481, 279.826 and 280.108nm) have been observed together with six other prominent Mn I lines in the laboratory helium plasma at a 47000K electron temperature and 6.6x1022m-3 electron density. With these plasma parameters the Stark broadening has been found to be an important mechanism in the Mn I line shape formation. Our measured Mn I Stark widths (W) are the first data in the literature. Stark widths are compared with line hyperfine structure splittings (?hfs). At above mentioned helium plasma conditions the line broadening due to hyperfine structure splitting of the lines is less than that of the Stark and Doppler broadening for the case of the Mn I lines under investigation. We estimate that at electron densities below 1020m-3 and electron temperatures below 4000K the components in the hyperfine structure play an important role in the mentioned Mn I line shape formation

2007-07-01

318

Pulse width modulation inverter with battery charger  

Energy Technology Data Exchange (ETDEWEB)

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

Slicker, James M. (Union Lake, MI)

1985-01-01

319

Jet impingement width calculation for flat plate  

International Nuclear Information System (INIS)

The flow behavior of the direct vessel injection (DVI) system is important in the analysis coolant accident (LOCA) in the Korean Next Generation Reactor (KNGR). Particularly, the flow regime in the downcomer demonstrates thermal-hydraulic characteristics which still defy full understanding. One of the unknown characteristics is the flow velocity profile. The flow behavior during injection is related to the steam path and the amount of bypass of the emergency core cooling (ECC) water. One can obtain the information in an analytical, numerical, or empirical way. First, the analytical method turns out to be only limited in solving the problem at hand because the available equations are not enough to account for all the unknown parameters relevant to the phenomena. In addition, the mathematical and physical methods do not necessarily yield the correct flow pattern. To overcome the limit of this analytical method, a simple experiment was conducted. Two flat acryl plates were used, and the conductance method was used to measure the flow width and thickness. The principle of measurement is that the resistance changes when the sensor reaches the fluid film. Results of the measurements are easily understandable. The outer boundary of and the center of the fluid flow are thick. Also, faster the injection velocity, the larger the flow width. It is remarkable that the velocities at the same spot are nearly identical regardless of the injection velocity. It is considered that, independently of the injected velocities, the spreading effect and the viscosity effect equalize the vertical velocity downstream

1999-05-01

320

Equivalence of conservation laws and equivalence of potential systems  

CERN Document Server

We study conservation laws and potential symmetries of (systems of) differential equations applying equivalence relations generated by point transformations between the equations. A Fokker-Planck equation and the Burgers equation are considered as examples. Using reducibility of them to the one-dimensional linear heat equation, we construct complete hierarchies of local and potential conservation laws for them and describe, in some sense, all their potential symmetries. Known results on the subject are interpreted in the proposed framework. This paper is an extended comment on the paper of J.-q. Mei and H.-q. Zhang [Internat. J. Theoret. Phys., 2006, in press].

Ivanova, N M; Ivanova, Nataliya M.; Popovych, Roman O.

2006-01-01

 
 
 
 
321

Approximation of reduced width amplitude and application to cluster decay width  

CERN Document Server

We propose a simple method to approximately evaluate reduced width amplitude (RWA) of a two-body spinless cluster channel using the norm overlap with the Brink-Bloch cluster wave function at the channel radius. The applicability of the present approximation is tested for the $^{16}$O+$\\alpha$ channel in $^{20}$Ne as well as the $\\alpha$+$\\alpha$ channel in $^8$Be. The approximation is found to be reasonable to evaluate the RWA for states near the threshold energy and it is useful to estimate the $\\alpha$-decay width of resonance states. The approximation is also applied to $^9$Li, and the partial decay width of the $^6$He($0^+_1$)+$t$ channel is discussed.

Kanada-En'yo, Yoshiko; Taniguchi, Yasutaka

2014-01-01

322

Measurement of the total width, the electronic width, and the mass of the Upsilon(10580) resonance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present a measurement of the parameters of the Upsilon(10580) resonance based on a dataset collected with the BABAR detector at the SLAC PEP-II asymmetric B factory. We measure the total width Gamma(tot)=(20.7 +/- 1.6 +/- 2.5) MeV, the electronic partial width Gamma(ee)=(0.321 +/- 0.017 +/- 0.029) keV and the mass M=(10579.3 +/- 0.4 +/- 1.2) MeV/c(2).

Gamba, Diego; Bianchi, Fabrizio

2005-01-01

323

First Digit Distribution of Hadron Full Width  

CERN Document Server

A phenomenological law, called Benford's law, states that the occurrence of the first digit, i.e., $1,2,...,9$, of numbers from many real world sources is not uniformly distributed, but instead favors smaller ones according to a logarithmic distribution. We investigate, for the first time, the first digit distribution of the full widths of mesons and baryons in the well defined science domain of particle physics systematically, and find that they agree excellently with the Benford distribution. We also discuss several general properties of Benford's law, i.e., the law is scale-invariant, base-invariant, and power-invariant. This means that the lifetimes of hadrons follow also Benford's law.

Shao, Lijing; 10.1142/S0217732309031223

2010-01-01

324

Direct measurement of the W boson width  

Energy Technology Data Exchange (ETDEWEB)

We present a direct measurement of the width of the W boson using the shape of the transverse mass distribution of W {yields} e{nu} candidates selected in 1 fb{sup -1} of data collected with the D0 detector at the Fermilab Tevatron collider in p{bar p} collisions at {radical}s = 1.96 TeV. We use the same methods and data sample that were used for our recently published W boson mass measurement, except for the modeling of the recoil, which is done with a new method based on a recoil library. Our result, 2.028 {+-} 0.072 GeV, is in agreement with the predictions of the standard model and is the most precise direct measurement result from a single experiment to date.

Abazov, V.M.; /Dubna, JINR; Abbott, B.; /Oklahoma U.; Abolins, M.; /Michigan State U.; Acharya, B.S.; /Tata Inst.; Adams, M.; /Illinois U., Chicago; Adams, T.; /Florida State U.; Aguilo, E.; /Alberta U. /Simon Fraser U. /McGill U.; Ahsan, M.; /Kansas State U.; Alexeev, G.D.; /Dubna, JINR; Alkhazov, G.; /St. Petersburg, INP; Alton, A.; /Michigan U. /Northeastern U.

2009-09-01

325

Characterizing Width Uniformity by Wave Propagation  

CERN Multimedia

This work describes a novel image analysis approach to characterize the uniformity of objects in agglomerates by using the propagation of normal wavefronts. The problem of width uniformity is discussed and its importance for the characterization of composite structures normally found in physics and biology highlighted. The methodology involves identifying each cluster (i.e. connected component) of interest, which can correspond to objects or voids, and estimating the respective medial axes by using a recently proposed wavefront propagation approach, which is briefly reviewed. The distance values along such axes are identified and their mean and standard deviation values obtained. As illustrated with respect to synthetic and real objects (in vitro cultures of neuronal cells), the combined use of these two features provide a powerful description of the uniformity of the separation between the objects, presenting potential for several applications in material sciences and biology.

Costa, L F; Schubert, D; Costa, Luciano da F.; Mutinari, Giancarlo; Schubert, David

2003-01-01

326

Measurement of neutron equivalent dose at INDUS-1 facility  

International Nuclear Information System (INIS)

Measurements of neutron equivalent doses using solid state nuclear track detector CR-39 foils and Kodak NTA nuclear emulsion in and around the Microtron hall and Booster hall at the Centre for Advanced Technology (CAT), Indore, have been carried out. The mapping was done in accelerator environments where low neutron fields are expected. The electron beam energy was 20 MeV and with current 10-20 mA with 1 ?s pulse width and 1Hz pulse repetition rate. The electrons travel through transport lines 1 and 2 and storage lines and are fed to the Booster synchrotron. Nineteen dosimeters of either type (CR-39 foils and Kodak NTA films) were exposed for periods up to 20 hours. The measured values from CR-39 foils show that during the operation the maximum value of neutron equivalent dose rates was of the order of 87.8 ?Sv/hr. (author)

1999-12-21

327

Lateral motion of terrace width distributions during step-flow growth  

Energy Technology Data Exchange (ETDEWEB)

We have observed two phenomena that occur during (Al,Ga)Sb lateral superlattice (LSL) growth which have implications on our understanding of adatom/step edge interactions on vicinal surfaces: shifts of the lateral distribution of terrace widths in the direction of step propagation, and lateral variations in the superlattice tilt angle that are correlated with the terrace width distribution. Both phenomena can be explained with a model of step-flow growth that includes both asymmetric adatom attachment at step edges and anisotropic adatom crossing over multiple step edges. A comparison between numerical simulations of this model and experimentally observed (Al,Ga)Sb LSL terrace width distributions leads to quantitative estimates of adatom migration characteristics. We find that at least one type of adatom, probably Ga, has a migration length equivalent to several terrace widths, and moves up and down step edges nearly isotropically. This method of determining adatom migration characteristics can be extended to any material that LSL layers can be grown above and below as terrace width markers.

Chalmers, S.A.; Tsao, J.Y. (Sandia National Laboratories, Division 1311, Albuquerque, New Mexico 87185 (United States)); Gossard, A.C. (Materials Department, University of California, Santa Barbara, California 93106 (United States))

1992-08-10

328

Equivalence Principle in Chameleon Models  

CERN Multimedia

Most theories that predict time and/or space variation of fundamental constants also predict violations of the Weak Equivalence Principle (WEP). Khoury and Weltmann proposed the chameleon model in 2004 and claimed that this model avoids experimental bounds on WEP. We present a contrasting view based on an approximate calculation of the two body problem for the chameleon field and show that the force depends on the test body composition. Furthermore, we compare the prediction of the force on a test body with E\\"otv\\"os type experiments and find that the chameleon field effect cannot account for current bounds.

Kraiselburd, Lucila; Salgado, Marcelo; Sudarsky, Daniel

2013-01-01

329

Derived equivalences for group rings  

CERN Document Server

A self-contained introduction is given to J. Rickard's Morita theory for derived module categories and its recent applications in representation theory of finite groups. In particular, Broué's conjecture is discussed, giving a structural explanation for relations between the p-modular character table of a finite group and that of its "p-local structure". The book is addressed to researchers or graduate students and can serve as material for a seminar. It surveys the current state of the field, and it also provides a "user's guide" to derived equivalences and tilting complexes. Results and proofs are presented in the generality needed for group theoretic applications.

König, Steffen

1998-01-01

330

Configuration of equivalent f electrons  

International Nuclear Information System (INIS)

The term 2F given to the ions Ce3+ and Yb3+ is due to an electron or to one hole, respectively, in the 4f configuration of the lanthanide elements. When the number of equivalent electrons (or holes) becomes larger than one, there is an increase in the number of terms. Considerations about the classification of terms to differentiate states of a given f sup(n) configuration are made on the basis of group theory. It is shown that different sets of quantum numbers are necessary to distinguish levels with the same representations and with different energies. (C.L.B.)

1983-10-09

331

Approximating the Minimum Equivalent Digraph  

CERN Document Server

The MEG (minimum equivalent graph) problem is, given a directed graph, to find a small subset of the edges that maintains all reachability relations between nodes. The problem is NP-hard. This paper gives an approximation algorithm with performance guarantee of pi^2/6 ~ 1.64. The algorithm and its analysis are based on the simple idea of contracting long cycles. (This result is strengthened slightly in ``On strongly connected digraphs with bounded cycle length'' (1996).) The analysis applies directly to 2-Exchange, a simple ``local improvement'' algorithm, showing that its performance guarantee is 1.75.

Khuller, S; Young, N E; Khuller, Samir; Raghavachari, Balaji; Young, Neal E.

1995-01-01

332

Equivalences entre conjectures de Soergel  

CERN Document Server

Soergel's category B_k(V) over a field k is defined from a Coxeter system (W,S) and a k-linear representation V of W. It's a categorification of the Hecke algebra of (W,S). In this article we prove that for some representations V and V' of W, Soergel's conjecture over B_k(V') is equivalent to that over B_k(V). In particular, when k=IR we can choose V' to be the geometric representation.

Libedinsky, Nicolas

2008-01-01

333

Transient radiation effects of CMOS circuits with different pulse widths  

International Nuclear Information System (INIS)

Transient radiation response on CMOS circuits were investigated for different pulse widths. CMOS circuits 4007, 4069 and 6264 were irradiated using 'Qiangguang-I' accelerator source. Latchup thresholds of CMOS inverters and upset level of CMOS SRAM with different pulse widths were obtained. The data clearly indicate dose-rate dependency on the pulse widths. The latchup threshold for 4007 and 4069 at 20 ns pulse width is 2 times that at 150 ns. The upset level for 6264 at 20 ns pulse width is 3 times that at 150 ns. The results show that the damage thresholds decrease with the increase of pulse widths. (authors)

2009-05-01

334

Research on Fairway Width Based on the Statistical Theory  

Directory of Open Access Journals (Sweden)

Full Text Available The fairway with certain width is one of prerequisite for ship’s safety navigation. Channel’s width is closely linked to ship’s safety navigation. It is essential to research channel’s width. The relationship between fairway’s width and marine accident is analyzed in the present study and mathematical model of fairway’s width is also put forward based on statistical theory in this study. Analysis shows that the fairway’s width mathematical model put forward in this study can provide good guide for fairway’s maintenance.

Ding Tian-Ming

2013-01-01

335

Light WIMPs And Equivalent Neutrinos  

CERN Document Server

Very light WIMPs (chi), thermal relics that annihilate late in the early Universe, change the energy and entropy densities at BBN and at recombination. BBN, in combination with the CMB, can remove some of the degeneracies among light WIMPs and equivalent neutrinos, constraining the existence and properties of each. Depending on the nature of the light WIMP (Majorana or Dirac fermion, real or complex scalar) the joint BBN + CMB analyses set lower bounds to m_chi in the range 0.5 - 5 MeV (m_chi/m_e > 1 - 10), and they identify best fit values for m_chi in the range 5 - 10 MeV. The joint BBN + CMB analysis finds a best fit value for the number of equivalent neutrinos, Delta N_nu ~ 0.65, nearly independent of the nature of the WIMP. In the absence of a light WIMP (m_chi > 20 MeV), N_eff = 3.05(1 + Delta N_nu /3). In this case, there is excellent agreement between BBN and the CMB, but the joint fit reveals Delta N_nu = 0.40+-0.17, disfavoring standard big bang nucleosynthesis (SBBN) (Delta N_nu = 0) at ~ 2.4 sigma...

Steigman, Gary

2014-01-01

336

SOL Width Scaling in the MAST Tokamak  

Science.gov (United States)

Target heat loads are determined in large part by the upstream SOL heat flux width, ?_h. Considerable effort has been made in the past to develop analytical and empirical scalings for ?h to allow reliable estimates to be made for the next-step device. The development of scalings for a large spherical tokamak (ST) such as MAST is particularly important both for development of the ST concept and for improving the robustness of scalings derived for conventional tokamaks. A first such scaling has been developed in MAST DND plasmas. The scaling was developed by flux-mapping data from the target Langmuir probe arrays to the mid-plane and fitting to key upstream parameters such as P_SOL, bar ne and q_95. In order to minimise the effects of co-linearity, dedicated campaigns were undertaken to explore the widest possible range of each parameter while keeping the remainder as fixed as possible. Initial results indicate a weak inverse dependence on P_SOL and approximately linear dependence on bar n_e. Scalings derived from consideration of theoretical edge transport models and integration with data from conventional devices is under way. The established scaling laws could be used for the extrapolations to the future machine such as Spherical Tokamak Power Plant (STPP). This work is jointly funded by Euratom and UK Department of Trade and Industry. J-W. Ahn would like to recognise the support of a grant from the British Foreign & Commonwealth Office.

Ahn, Joon-Wook; Counsell, Glenn; Connor, Jack; Kirk, Andrew

2002-11-01

337

Absolute decay width measurements in 16O  

International Nuclear Information System (INIS)

The reaction 126C(63Li, d)168O* at a 6Li bombarding energy of 42 MeV has been used to populate excited states in 16O. The deuteron ejectiles were measured using the high-resolution Munich Q3D spectrograph. A large-acceptance silicon-strip detector array was used to register the recoil and break-up products. This complete kinematic set-up has enabled absolute ?-decay widths to be measured with high-resolution in the 13.9 to 15.9 MeV excitation energy regime in 16O; many for the first time. This energy region spans the 14.4 MeV four-? breakup threshold. Monte-Carlo simulations of the detector geometry and break-up processes yield detection efficiencies for the two dominant decay modes of 40% and 37% for the ?+12C(g.s.) and a+12C(2+1) break-up channels respectively.

2012-09-18

338

Frequency dependence of pulse width for 150 radio normal pulsars  

CERN Document Server

The frequency dependence of pulse width is studied for 150 normal pulsars, mostly selected from the European Pulsar Network, of which the multi-frequency 10% pulse widths can be well fitted with the Thorsett relationship $W_{10}=A\

Chen, J L

2014-01-01

339

Study on tissue equivalent materials  

International Nuclear Information System (INIS)

A method to produce conducting tissue-equivalent material, consisting of a mixture of polyethylene, polyamide and carbon black, has been developed to get wall-material of the ionization chamber in radiation dosimetry. The most suitable condition in mixing of raw materials and molding technique have been presented. To accomplish homogeneity, mixing was repeated with the extruder which had been made for this purpose. The characteristics of the produced material, homogeneity of the chemical components, electric conductivity, rigidity to permit construction of chambers and moldability were satisfactory for dosimetric purpose. However the experimental absorption doses obtained by the practical ionization chamber with produced material wall were a little more than expected values. Further experimental results are necessary for discussion of the reason. (author)

1978-01-01

340

Einstein's equivalence principle in cosmology  

CERN Document Server

We study physical consequences of the Einstein equivalence principle (EEP) for a Hubble observer in FLRW universe. We introduce the local inertial coordinates with the help of a special conformal transformation. The local inertial metric is Minkowski flat and materialized by a congruence of time-like geodesics of static observers. The static observers are equipped with the ideal clocks measuring the proper time that is synchronized with the clocks of the Hubble observer. The local inertial metric is used for physical measurements of spacetime intervals with the ideal clocks and rulers. The special conformal transformation preserves null geodesics but does not keep invariant time-like geodesics. Moreover, it makes the rate of the local time coordinate dependent on velocity of the particle which makes impossible to rich the uniform parameterization of the world lines of static observers and light geodesics with a single parameter - they differ by the conformal factor of FLRW metric. The most convenient way to s...

Kopeikin, Sergei M

2013-01-01

 
 
 
 
341

Neutron dose rate equivalent monitor  

International Nuclear Information System (INIS)

The monitor proposed consists of a detection and an evaluation unit. The evaluation unit comprises and amplifier, a discriminator, a count ratemeter, and a power supply. The detection unit comprises a LiI(Eu) scintillator, a photomultiplier and a light guide. The detection unit is complete with a set of polyethylene moderators of different diameters. Direct dose equivalent monitoring of an invariable spectrum neutron field (ie., in the vicinity of points whose position relative to shielding does not change) is possible using one moderator. The set of moderators is used for measuring neutron fields in unknown spectrum sources or in sources whose shielding is frequently changed. The detection unit with the set of moderators is in fact a Bonner spectrometer. (H.S.)

1979-01-01

342

Glueball decay widths and glueball dominance of quarkonium decays  

International Nuclear Information System (INIS)

We present a realization of quarkonium decay violating the Okubo-Zweig-Iizuka (OZI) rule dominated by intermediate glueball resonances. This leads to glueball decay widths which interpolate OZI-rule allowed and -forbidden widths, i.e., glueball widths of the order of tens of MeV

1981-06-01

343

Formulae for partial widths derived from the Lindblad equation  

CERN Multimedia

A method for calculating partial widths of auto-ionizing states is proposed. It combines either a complex absorbing potential or exterior complex scaling with the Lindblad equation. The corresponding classical rate equations are reproduced, and the trace conservation inherent in the Lindblad equation ensures that the partial widths sums up to the total width of the initial auto-ionizing state.

Selstø, Sølve

2012-01-01

344

Pulse widths effects on scintillator saturation  

International Nuclear Information System (INIS)

A test was performed over an extensive range of irrradiance (approximately five orders of magnitude) to see to what extent organic scintillators responded linearly with x-ray input. At the highest levels of irradiance achievable with the experimental configuration, but only for pulses in the region of 4.0 ns or wider, a degree of nonlinear response was observed for some of the scintillators. The data suggest that at levels below 1 mJ/cm"2-ns it is safe to asume that for pulses 6.5 ns and shorter there is no significant level of nonlinearity to x rays with spectrum. For the cases of undoped NE111 and NE111 doped with 10 percent benzophenone, experimental conditions were such that it was possible to accumulate data significantly above the 1 mJ/cm"2-ns level of irradiance. It is with these cases that a nonlinear response was observed. It is assumed that the same nonlinearity would have also been noticed had experimental conditions been such that equivalent levels of irradiance could have been achieved at the time the other samples were studied

1978-01-01

345

Property C and Fine Homotopy Equivalences.  

Science.gov (United States)

The problem of dimensionality properties of infinite-dimensional spaces under fine homotopy equivalences is studied. The fact that the cell-like maps which are fine homotopy equivalences preserve countable dimension (property C) is proved.

J. Vanmill J. Mogilski

1984-01-01

346

From body burden to effective dose equivalent  

International Nuclear Information System (INIS)

The necessary data to calculate the effective committed dose equivalent and the effective dose-equivalent rate from measured body burdens are presented. Both ingestion and inhalation intakes are considered, for single intake as well as for continuous exposure

1982-01-01

347

Investigation of Equivalent Circuit for PEMFC Assessment  

International Nuclear Information System (INIS)

Chemical reactions occurring in a PEMFC are dominated by the physical conditions and interface properties, and the reactions are expressed in terms of impedance. The performance of a PEMFC can be simply diagnosed by examining the impedance because impedance characteristics can be expressed by an equivalent electrical circuit. In this study, the characteristics of a PEMFC are assessed using the AC impedance and various equivalent circuits such as a simple equivalent circuit, equivalent circuit with a CPE, equivalent circuit with two RCs, and equivalent circuit with two CPEs. It was found in this study that the characteristics of a PEMFC could be assessed using impedance and an equivalent circuit, and the accuracy was highest for an equivalent circuit with two CPEs

2011-09-01

348

On singular equivalences of Morita type  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Stable equivalences of Morita type preserve many interesting properties and is proved to be the appropriate concept to study for equivalences between stable categories. Recently the singularity category attained much attraction and Xiao-Wu Chen and Long-Gang Sun gave an appropriate definition of singular equivalence of Morita type. We shall show that under some conditions singular equivalences of Morita type have some biadjoint functor properties and preserve positive degree Hochschild homology.

Zhou, Guodong; Zimmermann, Alexander

2013-01-01

349

Auto-equivalences of stable module categories  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We construct nontrivial auto-equivalences of stable module categories for elementary, local symmetric algebras over a field k. These auto-equivalences are modeled after the spherical twists of Seidel and Thomas and the $\\mathbb{P}^n$-twists of Huybrechts and Thomas, which yield auto-equivalences of the derived category of coherent sheaves on a variety. For group algebras of p-groups in characteristic p we recover many of the auto-equivalences corresponding to endo-trivial mo...

Dugas, Alex

2014-01-01

350

Calculation of the effective dose equivalent  

Energy Technology Data Exchange (ETDEWEB)

From the conceptual basis of the Effective Dose Equivalent, as introduced by ICRP into the dose limitation system, the procedure for calculating the relevant mean tissue dose equivalents is derived. The reference adult male and female phantoms are described briefly. Proposals are made for completing the definition for the Effective Dose Equivalent Hsub(E). Conversion functions between exposure in free air and organ doses as well as the Effective Dose Equivalent are given for external photon irradiation.

Kramer, R.; Drexler, G. (Gesellschaft fuer Strahlen- und Umweltforschung m.b.H. Muenchen, Neuherberg (Germany, F.R.). Inst. fuer Strahlenschutz)

1982-01-01

351

Complex Variability of the H$\\alpha$ Emission Line Profile of the T Tauri Binary System KH 15D: The Influence of Orbital Phase, Occultation by the Circumbinary Disk, and Accretion Phenomenae  

CERN Multimedia

We have obtained 48 high resolution echelle spectra of the pre-main sequence eclipsing binary system KH~15D (V582 Mon, P = 48.37 d, $e$ $\\sim$ 0.6, M$_{A}$ = 0.6 M$_{\\odot}$, M$_{B}$ = 0.7 M$_{\\odot}$). The eclipses are caused by a circumbinary disk seen nearly edge on, which at the epoch of these observations completely obscured the orbit of star B and a large portion of the orbit of star A. The spectra were obtained over five contiguous observing seasons from 2001/2002 to 2005/2006 while star A was fully visible, fully occulted, and during several ingress and egress events. The H$\\alpha$ line profile shows dramatic changes in these time series data over timescales ranging from days to years. A fraction of the variations are due to "edge effects" and depend only on the height of star A above or below the razor sharp edge of the occulting disk. Other observed variations depend on the orbital phase: the H$\\alpha$ emission line profile changes from an inverse P Cygni type profile during ingress to an enhanced d...

Hamilton, Catrina M; Mundt, Reinhard; Herbst, William; Winn, Joshua N

2012-01-01

352

An equivalent sample circuit based on DSP  

International Nuclear Information System (INIS)

The author introduced an equivalent sample circuit which is based on DSP. With the technology of equivalent sample this circuit can sample signal with maximum 10 GHz equivalent sample rate under the condition of 40 MHz single-shot sample rate. The author describes the design theory and its advantage

2000-11-01

353

Some spectral equivalences between Schroedinger operators  

Energy Technology Data Exchange (ETDEWEB)

Spectral equivalences of the quasi-exactly solvable sectors of two classes of Schroedinger operators are established, using Gaudin-type Bethe ansatz equations. In some instances the results can be extended leading to full isospectrality. In this manner we obtain equivalences between PT-symmetric problems and Hermitian problems. We also find equivalences between some classes of Hermitian operators.

Dunning, C [Institute of Mathematics, Statistics and Actuarial Science, University of Kent (United Kingdom); Hibberd, K E; Links, J [Centre for Mathematical Physics, School of Physical Sciences, University of Queensland, Brisbane 4072 (Australia)], E-mail: t.c.dunning@kent.ac.uk, E-mail: keh@maths.uq.edu.au, E-mail: jrl@maths.uq.edu.au

2008-08-08

354

The material characteristic equivalency of anthropomorphic phantom  

International Nuclear Information System (INIS)

The radiation equivalent phantom is a human model used in the radiation dosimetry, radiation monitoring and radiation therapy. So, the research of the radiation equivalency of the materials used to fabricate the standard human phantom and to develop an effective method of measurement is one of foundation tasks. This paper describes the criticizing and measuring about equivalency

1993-10-18

355

Some spectral equivalences between Schrodinger operators  

CERN Document Server

Spectral equivalences of the quasi-exactly solvable sectors of two classes of Schrodinger operators are established, using Gaudin-type Bethe ansatz equations. In some instances the results can be extended leading to full isospectrality. In this manner we obtain equivalences between PT-symmetric problems and Hermitian problems. We also find equivalences between some classes of Hermitian operators.

Dunning, C; Links, J

2008-01-01

356

Some spectral equivalences between Schroedinger operators  

International Nuclear Information System (INIS)

Spectral equivalences of the quasi-exactly solvable sectors of two classes of Schroedinger operators are established, using Gaudin-type Bethe ansatz equations. In some instances the results can be extended leading to full isospectrality. In this manner we obtain equivalences between PT-symmetric problems and Hermitian problems. We also find equivalences between some classes of Hermitian operators

2008-08-08

357

Correlation between Line Width and Line Flux of Double-Peaked Broad Halpha of 3C390.3  

CERN Document Server

In this manuscript, we carefully check the correlation between the line width and the line flux of the double-peaked broad H$\\alpha$ of the well-known mapped AGN 3C390.3, in order to show some further distinctions between double-peaked emitters and normal broad line AGN. Based on the Virialization assumption and the empirical relation about $R_{BLR}$, one strong negative correlation of line parameters of the double-peaked broad lines should be expected for 3C390.3, such as the negative correlation confirmed for the mapped broad line object NGC5548. But, based on the public spectra around 1995 from the AGNWATCH project for 3C390.3, one reliable positive correlation is found. In the context of the proposed theoretical accretion disk model for double-peaked emitters, the unexpected positive correlation can be naturally explained, due to different time delays for inner parts and outer parts of disk-like BLR of 3C390.3. Moreover, the Virialization assumption is checked and found to be still available for 3C390.3. ...

Zhang, XueGuang

2012-01-01

358

Grounding equivalency of steel poles  

Energy Technology Data Exchange (ETDEWEB)

This article presents evidence that the embedded portion of a representative steel pole offer significant grounding capability. The Numerical Electromagnetics Code is used to compute the grounding resistance of a variety of grounding electrodes. The computational technique for determining ground resistance is first validated using standard ground rods. The computed results are then compared with the analytical equation for cylindrical ground rods as given in the IEEE Recommended Practices for Grounding Industrial and Commercial Power Systems. Since soil characteristics are of prime importance, two soil types are considered for each ground resistance computation: a relatively low conductivity sandy soil and a relatively high conductivity clay soil. Several different scenarios of grounding for the steel poles are considered. The ground resistance of the various electrodes considered here are computed using NEC-4 by applying the so-called fall-of-potential method. When the computed ground resistance of the coated steel pole is compared to that of a concrete pile, it is found that the coated steel pole is at least equal or better ground for bare lengths between four and five feet. Since the computed ground resistances on the coated steel pole are always larger than the actual grounding resistance, while concrete pile ground resistances are always smaller, the amount of bare length required on the coated steel pole to make it equivalent to the concrete pile ought to be significantly smaller than the given range of between four and five feet. 3 refs., 3 tabs., 5 figs.

Donohue, J. P.

2001-07-01

359

Equivalent Simplification Method of Micro-Grid  

Directory of Open Access Journals (Sweden)

Full Text Available The paper concentrates on the equivalent simplification method for the micro-grid system connection into distributed network. The equivalent simplification method proposed for interaction study between micro-grid and distributed network. Micro-grid network, composite load, gas turbine synchronous generation, wind generation are equivalent simplification and parallel connect into the point of common coupling. A micro-grid system is built and three phase and single phase grounded faults are performed for the test of the equivalent model of micro-grid. The simulation results show that the equivalent model of micro-grid is effective, and the dynamic of equivalent model is similar with the detailed model of micro-grid. The equivalent simplification method for the micro-grid network and distributed components is suitable for the study of micro-grid.  

Cai Changchun

2013-09-01

360

Measurement of the mass, full width, and radiative width of the B+ (1237) meson  

International Nuclear Information System (INIS)

An experiment was performed at Fermi National Accelerator Laboratory to investigate the coherent production of mesons on nuclear targets (lead and copper). The experiment used 200 GeV/c incident meson beam and a high resolution forward spectrometer consisting of proportional and drift chambers plus a liquid argon photon calorimeter. This thesis reports the results of the process ?+ + A ? ?+ omega + A. The ?+ omega spectrum was found to be dominated by the B+ (1237) meson. A fit was performed on the line shape of the ?+ omega mass spectrum and values of 1.271 +/- 0.011 GeV and 0.232 +/- 0.029 GeV were found for the mass and total width. The helicity zero decay probability of the omega, absolute value F02, was measured to be absolute value F02 = 0.15 +/- 0.035. The t distributions were analyzed allowing the electromagnetic and hadronic production processes to interfer. From these distributions a radiative width of 230 +/- 61 was extracted

1984-01-01

 
 
 
 
361

Ab initio calculations of nuclear widths via an integral relation  

CERN Document Server

I describe the computation of energy widths of nuclear states using an integral over the interaction region of ab initio variational Monte Carlo wave functions, and I present calculated widths for many states. I begin by presenting relations that connect certain short-range integrals to widths. I then present predicted widths for 5 <= A <= 9 nuclei, and I compare them against measured widths. They match the data more closely and with less ambiguity than estimates based on spectroscopic factors. I consider the consequences of my results for identification of observed states in ^8B, ^9He, and ^9Li. I also examine failures of the method and conclude that they generally involve broad states and variational wave functions that are not strongly peaked in the interaction region. After examining bound-state overlap functions computed from a similar integral relation, I conclude that overlap calculations can diagnose cases in which computed widths should not be trusted.

Nollett, Kenneth M

2012-01-01

362

On the Stark width regularities in doubly ionized spectra  

Energy Technology Data Exchange (ETDEWEB)

The existence of the Stark width dependence on the upper-level ionization potential of the quantum transition has been presented for twelve types of transitions in spectra of four doubly ionized atoms: N III, O III, S III and Cl III. On the basis of established regularities the Stark width values for 45 spectral lines, not measured or calculated before, have been predicted. A critical analysis of the existing experimental Stark width data is also given. (orig.)

Djenize, S. [Belgrade Univ. (Yugoslavia). Faculty of Physics

2000-04-01

363

Stability-Guaranteed Width Control for Hot Strip Mill  

Science.gov (United States)

We propose a stability-guaranteed width control (SGWC) for the hot strip finishing mill. It is shown that the proposed SGWC guarantees the stability of the width controller by the universal approximation of the neural network. It is shown through the field test in the hot strip mill of POSCO that the stability of the width controller is guaranteed by the proposed control scheme.

Park, Cheol Jae; Hwang, I. Cheol

364

Crack Width Analysis of Steel Fiber Reinforced Concrete Elements  

Directory of Open Access Journals (Sweden)

Full Text Available The article investigates the effectiveness of steel fiber reinforcement in RC concrete members in regard to ordinary reinforcement. The advantages and disadvantages of different shapes of steel fibers are discussed. The algorithm for calculating crack width based on EC2 and Rilem methodologies is presented. A comparison of theoretical and experimental crack widths has been performed. The relative errors of crack width predictions at different load levels were defined.Article in Lithuanian

Darius Ulbinas

2011-04-01

365

Equivalent linearization of a squeeze film damper  

Energy Technology Data Exchange (ETDEWEB)

The equivalent linearization of an intershaft squeeze film damper in a two shaft engine system is investigated. The two shaft centers at the damper position are assumed to move in different elliptical offset orbits and at synchronous frequency with the unbalanced rotor (e.g., the high pressure rotor). The nonlinear damper force is resolved into two orthogonal components along the absolute coordinate directions and, in turn, each of these force components is supposed to be equivalent to the sum of an average force, a linear spring force, and a linear damping force in the corresponding direction. By using the method of equivalent linearization by harmonic balance, the six parameters of the equivalent forces, including two average forces, two equivalent spring coefficients, and two equivalent damping coefficients, are expressed analytically by the squeeze film forces and the assumed orbital motion of the two shaft centers at the damper position. 10 references.

Chen, S.; Liu, S.

1986-10-01

366

Qualitative Logics and Equivalences for Probabilistic Systems  

CERN Multimedia

We investigate logics and equivalence relations that capture the qualitative behavior of Markov Decision Processes (MDPs). We present Qualitative Randomized CTL (QRCTL): formulas of this logic can express the fact that certain temporal properties hold over all paths, or with probability 0 or 1, but they do not distinguish among intermediate probability values. We present a symbolic, polynomial time model-checking algorithm for QRCTL on MDPs. The logic QRCTL induces an equivalence relation over states of an MDP that we call qualitative equivalence: informally, two states are qualitatively equivalent if the sets of formulas that hold with probability 0 or 1 at the two states are the same. We show that for finite alternating MDPs, where nondeterministic and probabilistic choices occur in different states, qualitative equivalence coincides with alternating bisimulation, and can thus be computed via efficient partition-refinement algorithms. On the other hand, in non-alternating MDPs the equivalence relations cann...

Chatterjee, Krishnendu; Faella, Marco; Legay, Axel

2009-01-01

367

K-equivalence in Birational Geometry  

CERN Multimedia

We give a survey of the background and recent development on the $K$-equivalence relation among birational manifolds. After a brief historical sketch of birational geometry, we define the $K$-partial ordering and $K$-equivalence in a birational class and discuss geometric situations that lead to these notions. One application to the filling-in problem for threefolds is given. We discuss the motivic aspect of $K$-equivalence relation. We believe that $K$-equivalent manifolds have the same Chow motive though we are unable to prove it at this moment. Instead we discuss various approaches toward the corresponding statements in different cohomological realizations. We also formulate the {\\it Main Conjectures} and prove a weak version of it. Namely, up to complex cobordism, $K$-equivalence can be decomposed into composite of classical flops. Finally we review some other current researches that are related to the study of $K$-equivalence relation.

Wang, C L

2002-01-01

368

On Projective Equivalence of Univariate Polynomial Subspaces  

Directory of Open Access Journals (Sweden)

Full Text Available We pose and solve the equivalence problem for subspaces of P_n, the (n+1 dimensional vector space of univariate polynomials of degree ? n. The group of interest is SL_2 acting by projective transformations on the Grassmannian variety G_kP_n of k-dimensional subspaces. We establish the equivariance of the Wronski map and use this map to reduce the subspace equivalence problem to the equivalence problem for binary forms.

Peter Crooks

2009-12-01

369

Homogeneous Dielectric Equivalents of Composite Material Shields  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper deals with the methodology of replacing complicated parts of an airplane skin by simple homogeneous equivalents, which can exhibit similar shielding efficiency. On one hand, the airplane built from the virtual homogeneous equivalents can be analyzed with significantly reduced CPU-time demands and memory requirements. On the other hand, the equivalent model can estimate the internal fields satisfactory enough to evaluate the electromagnetic immunity of the airplane.

Zvolensky, T.; Raida, Z.; Tobola, P.

2009-01-01

370

On graph equivalences preserved under extensions  

CERN Multimedia

Let R be an equivalence relation on graphs. By the strengthening of R we mean the relation R' such that graphs G and H are in the relation R' if for every graph F, the union of the graphs G and F is in the relation R with the union of the graphs H and F. We study strengthenings of equivalence relations on graphs. The most important case that we consider concerns equivalence relations defined by graph properties. We obtain results on the strengthening of equivalence relations determined by the properties such as being a k-connected graph, k-colorable, hamiltonian and planar.

Lonc, Zbigniew

2010-01-01

371

COMPLEX VARIABILITY OF THE H{alpha} EMISSION LINE PROFILE OF THE T TAURI BINARY SYSTEM KH 15D: THE INFLUENCE OF ORBITAL PHASE, OCCULTATION BY THE CIRCUMBINARY DISK, AND ACCRETION PHENOMENA  

Energy Technology Data Exchange (ETDEWEB)

We have obtained 48 high-resolution echelle spectra of the pre-main-sequence eclipsing binary system KH 15D (V582 Mon, P = 48.37 days, e {approx} 0.6, M{sub A} = 0.6 M{sub Sun }, M{sub B} = 0.7 M{sub Sun }). The eclipses are caused by a circumbinary disk (CBD) seen nearly edge on, which at the epoch of these observations completely obscured the orbit of star B and a large portion of the orbit of star A. The spectra were obtained over five contiguous observing seasons from 2001/2002 to 2005/2006 while star A was fully visible, fully occulted, and during several ingress and egress events. The H{alpha} line profile shows dramatic changes in these time series data over timescales ranging from days to years. A fraction of the variations are due to 'edge effects' and depend only on the height of star A above or below the razor sharp edge of the occulting disk. Other observed variations depend on the orbital phase: the H{alpha} emission line profile changes from an inverse P-Cygni-type profile during ingress to an enhanced double-peaked profile, with both a blue and a red emission component, during egress. Each of these interpreted variations are complicated by the fact that there is also a chaotic, irregular component present in these profiles. We find that the complex data set can be largely understood in the context of accretion onto the stars from a CBD with gas flows as predicted by the models of eccentric T Tauri binaries put forward by Artymowicz and Lubow, Guenther and Kley, and de Val-Borro et al. In particular, our data provide strong support for the pulsed accretion phenomenon, in which enhanced accretion occurs during and after perihelion passage.

Hamilton, Catrina M. [Department of Physics and Astronomy, Dickinson College, Carlisle, PA 17013 (United States); Johns-Krull, Christopher M. [Department of Physics and Astronomy, Rice University, Houston, TX 77005 (United States); Mundt, Reinhard [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Herbst, William [Astronomy Department, Wesleyan University, Middletown, CT 06459 (United States); Winn, Joshua N., E-mail: hamiltoc@dickinson.edu, E-mail: cmj@rice.edu, E-mail: mundt@mpia.de, E-mail: wherbst@wesleyan.edu, E-mail: jwinn@mit.edu [Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

2012-06-01

372

Widths of narrow mesons made from heavy quarks  

CERN Multimedia

Presents predictions for the electronic widths of neutral vector mesons made from heavy quarks. Relying principally on dispersion relations and asymptotic freedom of QCD, these results are quite model-independent. Photonic and total hadronic widths of C-even mesons are also discussed. (6 refs).

Farrar, Glennys R S; Okun, Lev Borisovich; Shifman, M A; Voloshin, M B; Zakharov, V I

1977-01-01

373

Inaccuracies introduced by single width blood pressure cuffs.  

Science.gov (United States)

Blood pressure cuff dimensions directly affect accuracy of blood pressure measurements. For accurate blood pressure measurements, the width of the cuff must be proportional to arm circumference. A cuff that is too narrow results in falsely high blood pressure values, and a cuff that is too wide results in falsely low values. Some blood pressure standards permit a single width cuff regardless of arm circumference. The purpose of this study was to evaluate whether 12?cm single width cuffs currently permitted by the British Hypertension Society (BHS) standard are sufficiently accurate to pass the Association for the Advancement of Medical Instrumentation (AAMI), BHS, and European Society of Hypertension (ESH) International Protocol (IP1) Working Group standards for accuracy. Each of 101 subjects was tested sequentially with both a single and a proportional width cuff in random order. Auscultatory blood pressure was determined by 2 observers using a double binaural stethoscope. Accuracy was determined by comparing the resulting differences with the AAMI, BHS, and IP1 standards for accuracy. The single width blood pressure cuff failed the AAMI accuracy standards for both systolic blood pressure on large arms and diastolic blood pressure on small and large arms, and overall. The single width cuffs, also, failed the BHS accuracy standards for diastolic BP. In conclusion, these single width cuffs could result in a significant number of people being misdiagnosed and mistreated for hypertension. Therefore, to avoid 'cuff hypertension' and 'cuff hypotension', the cuff width should be proportional to arm circumference. PMID:21048776

Andrews, Jeffrey C; Dewitt, Blake; Czerwien, Terry E; Bijelic, Miro; Latman, Neal S

2011-02-01

374

On the band width of resonant gravitational-wave antennas  

International Nuclear Information System (INIS)

The band width of a resonant gravitational-wave antenna depends on the ratio GAMMA of the wide-band noise to the narrow-band noise. For GAMMA ? 0 the band width becomes infinitely large, even if the coupling parameter between bar and transducer is small

1984-06-23

375

Band width of resonant gravitational-wave antennas  

Energy Technology Data Exchange (ETDEWEB)

The band width of a resonant gravitational-wave antenna depends on the ratio GAMMA of the wide-band noise to the narrow-band noise. For GAMMA->0 the band width becomes infinitely large, even if the coupling parameter between bar and transducer is small.

Pizzella, G. (Rome Univ. (Italy). Ist. di Fisica)

1984-07-23

376

He's variational iteration method for the modified equal width equation  

International Nuclear Information System (INIS)

Variational iteration method is introduced to solve the modified equal width equation. This method provides remarkable accuracy in comparison with the analytical solution. Three conservation quantities are reported. Numerical results demonstrate that this method is a promising and powerful tool for solving the modified equal width equation.

2009-03-15

377

Quantifying River Widths of North America from Satellite Imagery  

Science.gov (United States)

River width is a fundamental predictor variable in many hydrologic, geomorphic, and biogeochemical models, yet current large-scale models rely on theoretical hydraulic geometry relationships that do not fully capture natural variability in river form. Here we present the first high-resolution dataset of long-term mean width of North American rivers wider than 30 m. The dataset contains 7.93 million georeferenced width measurements derived from Landsat TM and ETM+ imagery that were acquired when rivers were most likely to be at mean discharge. We built the dataset by developing an automated procedure that selects and downloads raw imagery, creates cloud-free normalized difference water index images, histogram balances and mosaics them together, and produces a water mask using a dynamic water-land threshold technique. We then visually inspected and corrected the mask for errors and used RivWidth software to calculate river width at each river centerline pixel. We validated our dataset using >1000 United States Geological Survey and Water Survey of Canada in situ gauge station measurements. Error analysis shows a robust relationship between the remotely sensed widths and in situ gauge measurements with an r 2 = 0.86 (Spearman's = 0.81) and a mean absolute error of 27.5 m. We find that North American river widths lie on logarithmic frequency curve with some notable exceptions at widths SWOT) satellite mission.

Allen, G. H.; Pavelsky, T.; Miller, Z.

2013-12-01

378

On the width of. sigma. -hyperons in nuclei and atoms  

Energy Technology Data Exchange (ETDEWEB)

The width of a ..sigma..-hyperon in symmetric nuclear matter is investigated by using a boson exchange model for the ..sigma..N->..lambda..N amplitude. This amplitude is largely affected in nuclear matter yiedling a strong density dependence for the width of ..sigma..-hyperons in matter. At low densities this width is linear to the density, while, at higher density, it is strongly non-linear leading to saturation properties around rhoapprox.=0.7rho/sub 0/. This feature allows for a simultaneous description of the width of ..sigma.. atoms and the known ..sigma.. hypernuclear states. In addition, our model predicts a small width of about 5 MeV for hypernuclear 1s-states. (orig.).

Brockmann, R.; Oset, E.

1986-03-10

379

Research on Fairway Width Design in Curved Bridge Waters Channel  

Directory of Open Access Journals (Sweden)

Full Text Available Bridge construction can promote economic development but if the bridge layout is unreasonable, it would hinder ship’s safety navigation in the bridge area. There is little reference for fairway width design about curved bridge channel in ??inland river navigation standards?? of China. In this study, a fairway width design method in curved bridge channel was put forward by taking into account the scope of turbulent scope of pier, ship’s track width, drifting distance due to wind, drifting distance due to current, the scope of ship’s safety field and additional width in curved channel. The fairway width design concept for curved bridge channel presented in this studyit may provide reference for bridge design and other fairway layout.

Chi Hong-Fu

2013-01-01

380

On uncertainties in definition of dose equivalent  

International Nuclear Information System (INIS)

The author has entertained always the doubt that in a neutron field, if the measured value of the absorbed dose with a tissue equivalent ionization chamber is 1.02±0.01 mGy, may the dose equivalent be taken as 10.2±0.1 mSv. Should it be 10.2 or 11, but the author considers it is 10 or 20. Even if effort is exerted for the precision measurement of absorbed dose, if the coefficient being multiplied to it is not precise, it is meaningless. [Absorbed dose] x [Radiation quality fctor] = [Dose equivalent] seems peculiar. How accurately can dose equivalent be evaluated ? The descriptions related to uncertainties in the publications of ICRU and ICRP are introduced, which are related to radiation quality factor, the accuracy of measuring dose equivalent and so on. Dose equivalent shows the criterion for the degree of risk, or it is considered only as a controlling quantity. The description in the ICRU report 1973 related to dose equivalent and its unit is cited. It was concluded that dose equivalent can be considered only as the absorbed dose being multiplied by a dimensionless factor. The author presented the questions. (K.I.)

1995-03-01

 
 
 
 
381

Undecidability of performance equivalence of Petri nets  

CERN Multimedia

We investigate bisimulation equivalence on Petri nets under durational semantics. Our motivation was to verify the conjecture that in durational setting, the bisimulation equivalence checking problem becomes more tractable (which is the case, e.g., over communication-free nets). We disprove this conjecture in three of four proposed variants of durational semantics. The fourth case remains an interesting open problem.

Lasota, Slawomir

2009-01-01

382

Equivalency relations in magnetic space groups  

International Nuclear Information System (INIS)

The set of all possible magnetic space groups, belonging to the same crystallographic space group is generally redundant, many magnetic groups being equivalent by a change of axes and/or a shift of origin. The equivalency relations are established for each admissible k-vector in space groups with primitive and non primitive lattices. In turn a family of non equivalent magnetic space groups is entirely specified by giving for each crystallographic space group the admissible k-vectors and the coresponding equivalency relations. Their tabulation given here is equivalent to the complete enumeration of the 1421 magnetic space groups and, although more informative, does not take more space than the classical enumerations of Belov et al. and Opechowski et al

1975-01-01

383

Beyond Language Equivalence on Visibly Pushdown Automata  

DEFF Research Database (Denmark)

We study (bi)simulation-like preorder/equivalence checking on the class of visibly pushdown automata and its natural subclasses visibly BPA (Basic Process Algebra) and visibly one-counter automata. We describe generic methods for proving complexity upper and lower bounds for a number of studied preorders and equivalences like simulation, completed simulation, ready simulation, 2-nested simulation preorders/equivalences and bisimulation equivalence. Our main results are that all the mentioned equivalences and preorders are EXPTIME-complete on visibly pushdown automata, PSPACE-complete on visibly one-counter automata and P-complete on visibly BPA. Our PSPACE lower bound for visibly one-counter automata improves also the previously known DP-hardness results for ordinary one-counter automata and one-counter nets. Finally, we study regularity checking problems for visibly pushdown automata and show that they can be decided in polynomial time.

Srba, Jiri

2009-01-01

384

Equivalence in Ventilation and Indoor Air Quality  

Energy Technology Data Exchange (ETDEWEB)

We ventilate buildings to provide acceptable indoor air quality (IAQ). Ventilation standards (such as American Society of Heating, Refrigerating, and Air-Conditioning Enginners [ASHRAE] Standard 62) specify minimum ventilation rates without taking into account the impact of those rates on IAQ. Innovative ventilation management is often a desirable element of reducing energy consumption or improving IAQ or comfort. Variable ventilation is one innovative strategy. To use variable ventilation in a way that meets standards, it is necessary to have a method for determining equivalence in terms of either ventilation or indoor air quality. This study develops methods to calculate either equivalent ventilation or equivalent IAQ. We demonstrate that equivalent ventilation can be used as the basis for dynamic ventilation control, reducing peak load and infiltration of outdoor contaminants. We also show that equivalent IAQ could allow some contaminants to exceed current standards if other contaminants are more stringently controlled.

Sherman, Max; Walker, Iain; Logue, Jennifer

2011-08-01

385

Strong S-equivalence of ordered links  

CERN Multimedia

Recently Swatee Naik and Theodore Stanford proved that two S-equivalent knots are related by a finite sequence of doubled-delta moves on their knot diagrams. We show that classical S-equivalence is not sufficient to extend their result to ordered links. We define a new algebraic relation on Seifert matrices, called Strong S-equivalence, and prove that two oriented, ordered links L and L' are related by a sequence of doubled-delta moves if and only if they are Strongly S-equivalent. We also show that this is equivalent to the fact that L' can be obtained from L through a sequence of Y-clasper surgeries, where each clasper leaf has total linking number zero with L.

Gee, C G

2004-01-01

386

Bisimulations meet PCTL equivalences for probabilistic automata  

DEFF Research Database (Denmark)

Probabilistic automata (PAs) have been successfully applied in formal verification of concurrent and stochastic systems. Efficient model checking algorithms have been studied, where the most often used logics for expressing properties are based on probabilistic computation tree logic (PCTL) and its extension PCTL*. Various behavioral equivalences are proposed, as a powerful tool for abstraction and compositional minimization for PAs. Unfortunately, the equivalences are well-known to be sound, but not complete with respect to the logical equivalences induced by PCTL or PCTL*. The desire of a both sound and complete behavioral equivalence has been pointed out by Segala in [34], but remains open throughout the years. In this paper we introduce novel notions of strong bisimulation relations, which characterize PCTL and PCTL* exactly. We extend weak bisimulations that characterize PCTL and PCTL* without next operator, respectively. Further, we also extend the framework to simulation preorders. Thus, our paper bridges the gap between logical and behavioral equivalences and preorders in this setting.

Song, Lei; Zhang, Lijun

2013-01-01

387

Analysis of River Widths in the Amazon River Basin  

Science.gov (United States)

Rivers play a central role in the global hydrologic cycle, connecting atmospheric fluxes to soil moisture and groundwater storage through the circulation of water and transport of sediments from upland catchments to coastal settings over the landscape. River form on the regional-scale depends substantially on the variations in climate, drainage basin area, human activity, and substrate. Past studies of river form have focused mainly on small systems or network-form descriptions, rather than examining regional-scale continuous river morphology. This study represents the first-ever observational data set of continuous measurement of river widths in the Amazon River basin that are as wide as 50 meters or more. The widths are calculated using the RivWidth algorithm, which automatically calculates continuous river widths from satellite-derived water masks. We used Landsat TM and ETM+ images due to their long historical record, high spatial resolution, and wide global coverage. A total of 263 satellite images acquired during June to September, whenever possible, were used in creating the mask of Amazon River basin. A frequency analysis of river widths shows the wide variability in the distribution of complex-channels in the Amazon basin. The resulting map of river widths, when linked with Digital Elevation Models, can serve as an important tool in evaluating the basic control mechanisms on river formation and improve understanding of key relationships between width and variables such as basin area, lithology, climate, and human influence. The resulting width dataset will also be a significant contribution to the nascent Global River Width Database (GRWD) in the future.

Kustu, M. D.; Pavelsky, T. M.

2012-12-01

388

On the Stark width regularities in the singly ionized spectra  

Energy Technology Data Exchange (ETDEWEB)

The existence of the Stark width dependence on the upper-level ionization potential of the quantum transition have been presented for the sixteen types of transitions in spectras of nine singly ionized atoms: C II, N II, O II, F II, Ne II, P II, S II, Cl II and Ar II. On the basis of established regularities the Stark width values of 43 spectral lines, not measured or calculated before, have been predicted. Critical analysis of the existing experimental Stark width data is also given. (orig.) 50 refs.

Djenize, S.; Sreckovic, A.; Labat, J.; Platisa, M. [Belgrade Univ. (Yugoslavia). Faculty of Physics

1999-02-01

389

Why momentum width matters for atom interferometry with Bragg pulses  

CERN Document Server

Improving the precision of atom-based sensors by using large momentum transfer Bragg mirrors and beamsplitters is an exciting prospect. However, the effect of source momentum width on the efficiency of Bragg mirrors and beamsplitters and, more generally, on the phase sensitivity of an atom interferometer has been largely ignored. We have developed a theoretical method for optimizing Bragg beamsplitter and mirror pulses that includes the momentum width of the atomic cloud. Using these tools, we theoretically demonstrate that momentum width considerations are important, and in fact are crucial for optimizing Bragg pulses and comparing different atomic sources.

Szigeti, Stuart S; Hope, Joseph J; Robins, Nicholas P; Close, John D

2011-01-01

390

Peculiar Width Dependence of the Electronic Property of Carbon Nanoribbons  

CERN Multimedia

Nanoribbons (nanographite ribbons) are carbon systems analogous to carbon nanotubes. We characterize a wide class of nanoribbons by a set of two integers $$, and then define the width $w$ in terms of $p$ and $q$. Electronic properties are explored for this class of nanoribbons. Zigzag (armchair) nanoribbons have similar electronic properties to armchair (zigzag) nanotubes. The band gap structure of nanoribbons exhibits a valley structure with stream-like sequences of metallic or almost metallic nanoribbons. These sequences correspond to equi-width curves indexed by $w$. We reveal a peculiar dependence of the electronic property of nanoribbons on the width $w$.

Ezawa, M

2006-01-01

391

Probing eigenfunction nonorthogonality by parametric shifts of resonance widths  

CERN Document Server

Recently, it has been shown that the change of resonance widths in an open system under a perturbation of its interior is a sensitive indicator of the nonorthogonality of resonance states. We apply this measure to quantify parametric motion of the resonances. In particular, a strong redistribution of the widths is linked with the maximal degree of nonorthogonality. Then for weakly open chaotic systems we discuss the role of spectral rigidity on the statistical properties of the parametric width shifts, and derive the distribution of the latter in a picket-fence model with equidistant spectrum.

Savin, D V

2013-01-01

392

On the equivalence of dual theories  

CERN Document Server

We discuss the equivalence of two dual scalar field theories in 2 dimensions. The models are derived though the elimination of different fields in the same Freedman--Townsend model. It is shown that tree S-matrices of these models do not coincide. The 2-loop counterterms are calculated. It turns out that while one of these models is single-charged, the other theory is multi-charged. Thus the dual models considered are non-equivalent on classical and quantum levels. It indicates the possibility of the anomaly leading to non-equivalence of dual models.

Subbotin, A V

1995-01-01

393

Evaluation of spectral line width of atoms in liquid helium  

International Nuclear Information System (INIS)

Laser induced fluorescence experiments indicate change of spectral line profiles of atoms and molecules compared to the free system when embedded under liquid helium. Based on relativistic density functional approach a model has been proposed here to estimate the width of the spectral lines embedded under liquid helium in which the central atom resides within a cluster of helium atoms. The model assumes an overall floppy motion of the liquid helium atoms due to finite temperature and subsequent determination of the width from the ab initio estimated potential energy diagram. Calculated width of the resonance lines of Rb and Cs show good agreement with available laser spectroscopic data. -- Highlights: ? We study the change of the resonant transitions of Alkali atoms in liquid Helium. ? Our model allows fully relativistic ab initio calculations of the line width of such a transition. ? Comparison with experiment for Rb and Cs is nearly complete.

2011-07-11

394

Optical waveguide device with an adiabatically-varying width  

Science.gov (United States)

Optical waveguide devices are disclosed which utilize an optical waveguide having a waveguide bend therein with a width that varies adiabatically between a minimum value and a maximum value of the width. One or more connecting members can be attached to the waveguide bend near the maximum value of the width thereof to support the waveguide bend or to supply electrical power to an impurity-doped region located within the waveguide bend near the maximum value of the width. The impurity-doped region can form an electrical heater or a semiconductor junction which can be activated with a voltage to provide a variable optical path length in the optical waveguide. The optical waveguide devices can be used to form a tunable interferometer (e.g. a Mach-Zehnder interferometer) which can be used for optical modulation or switching. The optical waveguide devices can also be used to form an optical delay line.

Watts; Michael R. (Albuquerque, NM), Nielson; Gregory N. (Albuquerque, NM) [Albuquerque, NM

2011-05-10

395

The effect of buffer zone width on biodiversity  

DEFF Research Database (Denmark)

Field margin management for conservation purposes is a way to protect both functional biodiversity and biodiversity per se without considerable economical loss as field margins are less productive. However, the effect of width of the buffer zone on achievable biodiversity gains has received little attention in previous studies. In this paper we report on finding for syrphids, spiders and carabids, three taxonomic groups with different mobility, all important for conservation biological control. For all groups we found an effect of buffer zone width on their density. A buffer width of 6m was the narrowest that consistently promoted a higher abundance or activity of arthropods within the field area (outside the hedge bottom). However, a further increase in buffer width always increased the abundance and activity of arthropods a little more.

Navntoft, Søren; Sigsgaard, Lene

2012-01-01

396

The leptonic width of the neutral vector boson  

International Nuclear Information System (INIS)

We present the calculation of one-loop corrections to the decay width of the neutral vector boson into leptons, in the framework of the standard model of the electromagnetic and weak interactions. (orig.)

1981-03-12

397

Bisimulations Meet PCTL Equivalences for Probabilistic Automata  

CERN Document Server

Probabilistic automata (PA) have been successfully applied in the formal verification of concurrent and stochastic systems. Efficient model checking algorithms have been studied, where the most often used logics for expressing properties are based on PCTL and its extension PCTL*. Various behavioral equivalences are proposed for PAs, as a powerful tool for abstraction and compositional minimization for PAs. Unfortunately, the behavioral equivalences are well-known to be strictly stronger than the logical equivalences induced by PCTL or PCTL*. This paper introduces novel notions of strong bisimulation relations, which characterizes PCTL and PCTL* exactly. We also extend weak bisimulations characterizing PCTL and PCTL* without next operator, respectively. Thus, our paper bridges the gap between logical and behavioral equivalences in this setting.

Song, Lei; Godskesen, Jens Chr

2011-01-01

398

Checking Equivalence of Quantum Circuits and States  

CERN Document Server

Quantum computing promises exponential speed-ups for important simulation and optimization problems. It also poses new CAD problems that are similar to, but more challenging, than the related problems in classical (non-quantum) CAD, such as determining if two states or circuits are functionally equivalent. While differences in classical states are easy to detect, quantum states, which are represented by complex-valued vectors, exhibit subtle differences leading to several notions of equivalence. This provides flexibility in optimizing quantum circuits, but leads to difficult new equivalence-checking issues for simulation and synthesis. We identify several different equivalence-checking problems and present algorithms for practical benchmarks, including quantum communication and search circuits, which are shown to be very fast and robust for hundreds of qubits.

Viamontes, George F; Hayes, John P

2007-01-01

399

Nuclear Regulatory Commission equivalency evaluation report  

International Nuclear Information System (INIS)

This paper provides the basis for concluding that using the seismic design criteria, defined in DOE order 4580.28, Natural Phenomena Hazards Mitigation, and its implementing standards provides safety equivalent to NRC criteria

1995-01-01

400

Derived equivalence and non-vanishing loci  

CERN Document Server

The paper proposes and motivates a conjecture on the invariance of cohomological support loci under derived equivalence. It contains a proof in the case of surfaces, and explains further developments and consequences.

Popa, Mihnea

2012-01-01

 
 
 
 
401

On the equivalence of chaos control systems  

International Nuclear Information System (INIS)

For a given chaotic system, different control systems can be constructed depending on which parameter is tuned or where the external input is added. We prove that two different feedback control systems are qualitatively equivalent if they are feedback linearizable

2003-01-01

402

Dosimetry with tissue equivalent plastic ionization chamber  

International Nuclear Information System (INIS)

Tissue equivalent plastics have been widely used as the materials for radiation detectors and phantoms, and their muscle equivalency is reasonable for the radiation beam for radiotherapy. As the kerma factor for light elements is not known well above 30 MeV, it is desirable to make a tissue equivalent plastic, in which oxygen content is improved rather than that in present tissue equivalent plastics. One of the difficulties in the standardization of neutron dosimetry arised from that the different dosimetric constants have been used at respective institutions, and this is clear from the results of intercomparison of some neutron doses. The pair chamber method is valid for mixed fields, bacause neutron and ?-ray doses can be measured separately. However, the saturation characteristic of carbon chambers is very poor, therefore the correction factor must be determined experimentally for each individual ionization chamber. (Kobatake, H.)

1978-11-01

403

Dose equivalent index for fast electrons  

International Nuclear Information System (INIS)

Monte Carlo calculations of the deep and shallow dose equivalent index produced by electron beams in the energy region 5-22 MeV have been performed for unidirectional, opposing, rotating and isotropic irradiations of the spherical tissue equivalent phantom. The observed dose maxima are attributed to multiple scattering and range effects and occur in the outer 10 mm shell. The isotropy factor varies from 2.48 at 5 MeV to 1.89 at 22 MeV. The signal of a detector with isotropic response and wall thickness 0.5 g/cm"2 is shown to be a suitable measure of dose equivalent index for fast electrons. The average dose equivalent in the spherical phantom is discussed as an alternative concept. (author)

1981-01-01

404

Topological equivalence in families of complex polynomials  

CERN Document Server

We show that two polynomials, joined by a continuous family of polynomial functions $f_s \\colon \\mathbb{C}^n \\to \\mathbb{C}$ of constant degree and with isolated singularities, are topologically equivalent if $n\

Bodin, A; Bodin, Arnaud; Tibar, Mihai

2003-01-01

405

Affective equivalence relations in synaesthetic phrases  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper argues that the semantic processes underlying proper (e. g. warm colour) and physiognomic synaesthesias (e. g. cheerful colour) are based not on conceptual mapping, but on affective equivalence relations.

B Borka, Sz Nt

2011-01-01

406

About the modern "experimental value" of W boson width.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

It is shown that the methods which have been used up to now to determine the $W$ width from the $p\\bar p$ data confirm the SM predictions for some combinations of various phenomenological parameters, however, they do not give an independent value for the $W$ width. Moreover, the accuracy that could be achieved in future experimental checks of SM predictions for such quantities is limited by effects which require detailed theoretical study.

Ginzburg, I. F.; Melnikov, K.

1995-01-01

407

A direct measurement of W boson decay width  

CERN Document Server

Based on 85 pb$^{-1}$ data of \\ppbar collisions at $\\sqrt{s}=1.8$ \\tev\\ collected using the D{\\O}detector at Fermilab during the 1994-1995 run of the Tevatron, we present a direct measurement of the total decay width of the \\wb\\ boson, $\\Gamma_W$. The width is determined from the transverse mass spectrum in the $W \\to e+\

Abazov, V M; Abdesselam, A; Abolins, M; Abramov, V; Acharya, B S; Adams, D L; Adams, M; Ahmed, S N; Alexeev, G D; Alton, A; Alves, G A; Anderson, E W; Arnoud, Y; Avila, C; Baarmand, M M; Babintsev, V V; Babukhadia, L; Bacon, Trevor C; Baden, A; Baldin, B Yu; Balm, P W; Banerjee, S; Barberis, E; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Bauer, D; Bean, A; Beaudette, F; Begel, M; Belyaev, A; Beri, S B; Bernardi, G; Bertram, I; Besson, A; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Bhattacharjee, M; Blazey, G; Blekman, F; Blessing, S; Böhnlein, A; Bozhko, N; Bolton, T A; Borcherding, F; Bos, K; Bose, T; Brandt, A; Breedon, R; Briskin, G; Brock, R; Brooijmans, G; Bross, A; Buchholz, D; Bühler, M; Büscher, V; Burtovoi, V S; Butler, J M; Canelli, F; Carvalho, W; Casey, D; Casilum, Z; Castilla-Valdez, H; Chakraborty, D; Chan, K M; Chekulaev, S V; Cho, D K; Choi, S; Chopra, S; Christenson, J H; Chung, M; Claes, D; Clark, A R; Coney, L; Connolly, B; Cooper, W E; Coppage, D; Crepe-Renaudin, S; Cummings, M A C; Cutts, D; Davis, G A; De, K; De Jong, S J; Demarteau, M; Demina, R; Demine, P; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Doulas, S; Ducros, Y; Dudko, L V; Duensing, S; Duflot, L; Dugad, S R; Duperrin, A; Dyshkant, A; Edmunds, D; Ellison, J; Eltzroth, J T; Elvira, V D; Engelmann, R; Eno, S; Eppley, G; Ermolov, P; Eroshin, O V; Estrada, J; Evans, H; Evdokimov, V N; Fahland, T; Fein, D; Ferbel, T; Filthaut, Frank; Fisk, H E; Fisyak, Yu; Flattum, E; Fleuret, F; Fortner, M; Fox, H; Frame, K C; Fu, S; Fuess, S; Gallas, E; Galjaev, A N; Gao, M; Gavrilov, V; Genik, R J; Genser, K; Gerber, C E; Gershtein, Yu; Gilmartin, R; Ginther, G; Gómez, B; Goncharov, P I; Gordon, H; Goss, L T; Gounder, K; Goussiou, A; Graf, N; Grannis, P D; Green, J A; Greenlee, H; Greenwood, Z D; Grinstein, S; Groer, L; Grünendahl, S; Sen-Gupta, A; Gurzhev, S N; Gutíerrez, G; Gutíerrez, P; Hadley, N J; Haggerty, H; Hagopian, S; Hagopian, V; Hall, R E; Hansen, S; Hauptman, J M; Hays, C; Hebert, C; Hedin, D; Heinmiller, J M; Heinson, A P; Heintz, U; Hildreth, M D; Hirosky, R; Hobbs, J D; Hoeneisen, B; Huang, Y; Iashvili, I; Illingworth, R; Ito, A S; Jaffré, M; Jain, S; Jesik, R; Johns, K; Johnson, M; Jonckheere, A; Jöstlein, H; Juste, A; Kahl, W; Kahn, S; Kajfasz, E; Kalinin, A M; Karmanov, D; Karmgard, D; Kehoe, R; Khanov, A; Kharchilava, A I; Kim, S K; Klima, B; Knuteson, B; Ko, W; Kohli, J M; Kostritskii, A V; Kotcher, J; Kothari, B; Kotwal, A V; Kozelov, A V; Kozlovskii, E A; Krane, J; Krishnaswamy, M R; Krivkova, P; Krzywdzinski, S; Kubantsev, M A; Kuleshov, S; Kulik, Y; Kunori, S; Kupco, A; Kuznetsov, V E; Landsberg, G L; Lee, W M; Leflat, A; Leggett, C; Lehner, F; Leonidopoulos, C; Li, J; Li, Q Z; Lima, J G R; Lincoln, D; Linn, S L; Linnemann, J; Lipton, R; Lucotte, A; Lueking, L; Lundstedt, C; Luo, C; Maciel, A K A; Madaras, R J; Malyshev, V L; Manankov, V; Mao, H S; Marshall, T; Martin, M I; Mayorov, A A; McCarthy, R; McMahon, T; Melanson, H L; Merkin, M; Merritt, K W; Miao, C; Miettinen, H; Mihalcea, D; Mishra, C S; Mokhov, N V; Mondal, N K; Montgomery, H E; Moore, R W; Mostafa, M; Da Motta, H; Mutaf, Y; Nagy, E; Nang, F; Narain, M; Narasimham, V S; Naumann, N A; Neal, H A; Negret, J P; Nomerotski, A; Nunnemann, T; O'Neil, D; Oguri, V; Olivier, B; Oshima, N; Padley, P; Pan, L J; Papageorgiou, K; Parashar, N; Partridge, R; Parua, N; Paterno, M; Patwa, A; Pawlik, B; Peters, O; Petroff, P; Piegaia, R; Pope, B G; Popkov, E; Prosper, H B; Protopopescu, S D; Przybycien, M B; Qian, J; Raja, R; Rajagopalan, S; Ramberg, E; Rapidis, P A; Reay, N W; Reucroft, S; Ridel, M; Rijssenbeek, M; Rizatdinova, F K; Rockwell, T; Roco, M T; Royon, C; Rubinov, P; Ruchti, R; Rutherfoord, J; Sabirov, B M; Sajot, G; Santoro, A F S; Sawyer, L; Schamberger, R D; Schellman, H; Schwartzman, A; Sen, N; Shabalina, E; Shivpuri, R K; Shpakov, D; Shupe, M; Sidwell, R A; Simák, V; Singh, H; Sirotenko, V I; Slattery, P F; Smith, E; Smith, R P; Snihur, R; Snow, G R; Snow, J; Snyder, S; Solomon, J; Song, Y; Sorin, V; Sosebee, M; Sotnikova, N; Soustruznik, K; Souza, M; Stanton, N R; Steinbruck, G; Stephens, R W; Stoker, D; Stolin, V; Stone, A; Stoyanova, D A; Strang, M A; Strauss, M; Strovink, M; Stutte, L; Sznajder, A; Talby, M; Taylor, W; Tentindo-Repond, S; Tripathi, S M; Trippe, T G; Turcot, A S; Tuts, P M; Vaniev, V; Van Kooten, R; Varelas, N; Vertogradov, L S; Villeneuve-Séguier, F; Volkov, A A; Vorobev, A P; Wahl, H D; Wang, H; Wang, Z M; Warchol, J; Watts, G; Wayne, M; Weerts, H; White, A; White, J T; Whiteson, D; Wijngaarden, D A; Willis, S; Wimpenny, S J; Womersley, J; Wood, D R; Xu, Q; Yamada, R; Yamin, P; Yasuda, T; Yatsunenko, Y A; Yip, K; Youssef, S; Yu, J; Zanabria, M; Zhang, X; Zheng, H; Zhou, B; Zhou, Z; Zielinski, M; Zieminska, D; Zieminski, A; Zutshi, V; Zverev, E G; Zylberstejn, A

2002-01-01

408

An interactive method for digital tree-ring width measurement  

Directory of Open Access Journals (Sweden)

Full Text Available We present a new interactive method for tree-ring width determination. It uses a high resolution scanner and a PC. A program to process scanned tree-ring images was developed in Interactive Data Language (IDL 5.0 environment. The method successfully performs interactive tree-ring image analysis without high-cost complex equipment. A simple test was used to check the precision of ring width measurements from a sliced tree sample, Pinus taeda on Southern Brazil.

Alan Prestes

2004-08-01

409

Echo width of foam supports used in scattering measurements  

DEFF Research Database (Denmark)

Theoretically and experimentally determined echo widths of dielectric cylinders having circular, triangular, and quadratic cross sections have been compared. The cylinders were made of foam material having a relative dielectric constant of about 1.035. The purpose of the investigation was to find a cross section with a small echo width. The result can be used in selecting a proper support for test objects in backscattering measurement studies.

Appel-Hansen, Jørgen

1979-01-01

410

Calculation of the Higgs boson decay widths into boson pairs  

International Nuclear Information System (INIS)

The decay widths of the Higgs boson into ??,Z?,ZZ and W"+W"- are calculated on the one-loop level of the electroweak theory. Exact analytic formulae in terms of complex-valued dilogarithms are obtained. The dependence of the decay widths on the Higgs boson mass and on the top-quark mass are investigated. 12 refs.; 10 figs.; 1 tab

1991-01-01

411

Hadronic off-shell width of meson resonances  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Within the resonance chiral effective theory we study the dressed propagators of the spin-1 fields, which arise from a Dyson-Schwinger resummation perturbatively constructed from loop diagrams with absorptive contributions in the s channel. We apply the procedure to the vector pion form factor and elastic ?? scattering to obtain the off-shell width of the ?0 meson. We adopt a definition of the off-shell width of spin-1 meson resonances that satisfies the requirements of analyticity, unitar...

Go?mez Dumm, D.; Pich, Antonio; Portole?s, Jorge

2000-01-01

412

Domain Wall Width in Different Ferroelectrics via Perturbation Route  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The domains are of fundamental interest for engineering a ferroelectric material. The domain wall and its width control the ferroelectric behavior to a great extent. The stability of polarization in the context of Landau-Ginzburg free energy functional has been worked out in a previous work by a perturbation approach, where two limits of domain wall width were estimated within the stability zone and they were also found to correspond well with the data on lithium niobate and lithium tantalate...

Anik Bandyopadhyay; Arnab Sengupta; Kamal Choudhary; Bandyopadhyay, Asis K.; Ray, Pratap C.

2012-01-01

413

Rossman/Chance Applet Collection: Selecting Histogram Bin-Width  

Science.gov (United States)

This applet demonstrates the impact of data bin width on the display of information in histograms. The user is able to control the bin width and the axes of the histogram with the resultant changes shown immediately. There are two data sets available for use, and the user can edit the data or create new data sets. This is part of a larger collection of applets on statistics from the California Poly San Luis Obispo.

Rossman, Allan; Chance, Beth

2008-09-04

414

Homeomorphisms, homotopy equivalences and chain complexes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis concerns the relationship between bounded and controlled topology and in particular how these can be used to recognise which homotopy equivalences of reasonable topological spaces are homotopic to homeomorphisms. Let f : X ? Y be a simplicial map of finite-dimensional locally finite simplicial complexes. Our first result is that f has contractible point inverses if and only if it is an ?- controlled homotopy equivalences for all ? > 0, if and only if f × id : X...

Adams-florou, Spiros; Florou, Spiros Adams

2012-01-01

415

Homeomorphisms, homotopy equivalences and chain complexes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis concerns the relationship between bounded and controlled topology and how these can be used to recognise which homotopy equivalences of reasonable topological spaces are homotopic to homeomorphisms. Let $f:X\\to Y$ be a simplicial map of finite-dimensional locally finite simplicial complexes. We prove that $f$ has contractible point inverses if and only if it is an $\\epsilon$-controlled homotopy equivalences for all $\\epsilon>0$, if and only if $f\\times\\mathrm{id}...

Adams-florou, Spiros

2012-01-01

416

Quasi-proper meromorphic equivalence relations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this article is to complete results of [M.00] and [B.08] and to show that they imply a rather general existence theorem for meromorphic quotient of strongly quasi-proper meromorphic equivalence relations. In this context, generic equivalence classes are asked to be pure dimensionnal closed analytic subset with finitely many irreducible components. As an application of these methods we prove a Stein factorization theorem for a strongly quasi-proper map

Barlet, Daniel

2010-01-01

417

The Pfaffian-Grassmannian equivalence revisited  

CERN Document Server

We give a new proof of the 'Pfaffian-Grassmannian' derived equivalence between certain pairs of non-birational Calabi-Yau threefolds. Our proof follows the physical constructions of Hori and Tong, and we factor the equivalence into three steps by passing through some intermediate categories of (global) matrix factorizations. The first step is global Knoerrer periodicity, the second comes from a birational map between Landau-Ginzburg B-models, and for the third we develop some new techniques.

Addington, Nicolas; Segal, Ed

2014-01-01

418

Criteria equivalent to the Riemann Hypothesis  

CERN Document Server

We give a brief overview of a few criteria equivalent to the Riemann Hypothesis. Next we concentrate on the Riesz and B{\\'a}ez-Duarte criteria. We proof that they are equivalent and we provide some computer data to support them. It is not compressed to six pages version of the talk delivered by M.W. during the XXVII Workshop on Geometrical Methods in Physics, 28 June -- 6 July, 2008, Bia{\\l}owie{\\.z}a, Poland.

Cislo, J

2008-01-01

419

Dose equivalent rate calculation tool for FBFC  

International Nuclear Information System (INIS)

The authors present the results obtained by a software designed to compute dose equivalent rate for the critical workstations of the FBFC plant in Romans, France, which will have to deal with an uranium more heavily loaded with U232. The uranium spectrum and the ageing time can be varied in order to visualize the evolution of the dose equivalent rate in different locations with respect to the ageing time

2010-04-28

420

Dark matter and the equivalence principle  

Science.gov (United States)

A survey is presented of the current understanding of dark matter invoked by astrophysical theory and cosmology. Einstein's equivalence principle asserts that local measurements cannot distinguish a system at rest in a gravitational field from one that is in uniform acceleration in empty space. Recent test-methods for the equivalence principle are presently discussed as bases for testing of dark matter scenarios involving the long-range forces between either baryonic or nonbaryonic dark matter and ordinary matter.

Frieman, Joshua A.; Gradwohl, Ben-Ami

1993-01-01

 
 
 
 
421

Using Constraints for Equivalent Mutant Detection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In mutation testing the question whether a mutant is equivalent to its program is important in order to compute the correct mutation score. Unfortunately, answering this question is not always possible and can hardly be obtained just by having a look at the program's structure. In this paper we introduce a method for solving the equivalent mutant problem using a constraint representation of the program and its mutant. In particularly the approach is based on distinguishing t...

Nica, Simona; Wotawa, Franz

2012-01-01

422

Equivalence Theory Applied to Anisotropic Thin Plates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We extend the Equivalence Theory (ET) formulated by Absi [1] for the statics of isotropic materials to the statics and dynamics of orthotropic materials. That theory relies on the assumption that any real body mod- eling may be substituted by another one that, even though it may possibly have material constitutive laws and geometric properties with no physical sense (like negative cross sections or Young modulus), is intended to be more advantageous for calculus. In our approach, the equivale...

Madjid Haddad; Yves Gourinat; Miguel Charlotte

2011-01-01

423

Quantitative and methodological aspects of stimulus equivalence  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The number of different ways of linking stimuli in the training phase of a conditional discrimination procedure designed to teach equivalence relations has hitherto been underestimated. An algorithm from graph theory that produces the correct number of such different ways is given. The establishment of equivalence relations requires transitive stimulus control. A misconception in a previous analysis of the conditions necessary for demonstrating transitive stimulus control is indicated. This m...

O Mara, Henry

1991-01-01

424

Equivalence relations and the reinforcement contingency.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Where do equivalence relations come from? One possible answer is that they arise directly from the reinforcement contingency. That is to say, a reinforcement contingency produces two types of outcome: (a) 2-, 3-, 4-, 5-, or n-term units of analysis that are known, respectively, as operant reinforcement, simple discrimination, conditional discrimination, second-order conditional discrimination, and so on; and (b) equivalence relations that consist of ordered pairs of all positive elements that...

Sidman, M.

2000-01-01

425

The therapeutic equivalence of complex drugs  

Digital Repository Infrastructure Vision for European Research (DRIVER)

When the patent of a small molecule drug expires generics may be introduced. They are considered therapeutically equivalent once pharmaceutical equivalence (i.e. identical active substances) and bioequivalence (i.e. comparable pharmacokinetics) have been established in a cross-over volunteer study. However this generic paradigm cannot be applied to complex drugs as biologics and a number of other therapeutic modalities. For copies of biologics the European Medicine Agency and other regulatory...

Schellekens, H.; Klinger, E.; Mu?hlebach, S.; Brin, J-f; Storm, G.; Crommelin, D. J. A.

2011-01-01

426

Asymptotic equivalence of sequences and summability  

Directory of Open Access Journals (Sweden)

Full Text Available For a sequence-to-sequence transformation A, let RmAx=∑n≥m|(Axn| and μmAx=supn≥m|(Axn|. The purpose of this paper is to study the relationship between the asymptotic equivalence of two sequences (limnxn/yn=1 and the variations of asymptotic equivalence based on the ratios RmAx/RmAy and μmAx/μmAy.

Jinlu Li

1997-12-01

427

Arthroscopic Transosseous-Equivalent Rotator Cuff Repair  

Science.gov (United States)

Rotator cuff repair techniques continue to evolve in an effort to improve repair biomechanics, maximize the biologic environment for tendon healing, and ultimately improve patient outcomes. The arthroscopic transosseous-equivalent technique was developed to replicate the favorable tendon-bone contact area for healing seen in open transosseous tunnel repair. In this technical note and accompanying video, we present our all-arthroscopic transosseous-equivalent rotator cuff repair technique with a focus on technical pearls.

Lavery, Kyle P.; Rasmussen, Jeffrey F.; Dhawan, Aman

2013-01-01

428

Wilf Equivalence for the Charge Statistic  

CERN Multimedia

Savage and Sagan have recently defined a notion of st-Wilf equivalence for any permutation statistic st and any two sets of permutations $\\Pi$ and $\\Pi'$. In this paper we give a thorough investigation of st-Wilf equivalence for the charge statistic on permutations and use a bijection between the charge statistic and the major index to prove a conjecture of Dokos, Dwyer, Johnson, Sagan and Selsor regarding powers of 2 and the major index.

Killpatrick, Kendra

2012-01-01

429

Comprehensive intermaxillary tooth width proportion of Bangkok residents  

Directory of Open Access Journals (Sweden)

Full Text Available Proper occlusion depends on the correct width ratio between upper and lower teeth, known as Bolton's ratio. In fact, this ratio can be calculated for each pair of teeth from the central incisor to the first permanent molar. This set of ratios, known as comprehensive cumulative percentage ratios (CPRs, can be used not only to determine which tooth or teeth have a tooth width discrepancy, but can also enable the partial graphical analysis of tooth width discrepancy when there is agenesis of certain permanent teeth. Although CPRs have been calculated for Caucasians, tooth width is known to vary depending on racial origin. Therefore, a test of differences between racial groups should be carried out. If these ratios of the Caucasians and Bangkokians are significantly different, the ratio of the Bangkokians is recommended. The objective of this study was to measure tooth size disproportion for Thai patients and to calculate a corresponding set of CPRs. Thirty-seven pairs of dental models were made from a group of Bangkok residents with normal occlusion. Mesiodistal tooth width was measured for each model. The intra- and inter-examiner measurement errors were ascertained as insignificant (p > 0.05. CPRs were then calculated and compared to those derived from other studies. Ten of thirteen CPRs were significantly different from corresponding values derived from Caucasians. We conclude that tooth width ratios vary between different racial groups, and therefore that these should be calculated specifically for each patient racial group.

Somchai Manopatanakul

2011-04-01

430

Crack width monitoring of concrete structures based on smart film  

Science.gov (United States)

Due to its direct link to structural security, crack width is thought to be one of the most important parameters reflecting damage conditions of concrete structures. However, the width problem is difficult to solve with the existing structural health monitoring methods. In this paper, crack width monitoring by means of adhering enameled copper wires with different ultimate strains on the surface of structures is proposed, based on smart film crack monitoring put forward by the present authors. The basic idea of the proposed method is related to a proportional relationship between the crack width and ultimate strain of the broken wire. Namely, when a certain width of crack passes through the wire, some low ultimate strain wires will be broken and higher ultimate strain wires may stay non-broken until the crack extends to a larger scale. Detection of the copper wire condition as broken or non-broken may indicate the width of the structural crack. Thereafter, a multi-layered stress transfer model and specimen experiment are performed to quantify the relationship. A practical smart film is then redesigned with this idea and applied to Chongqing Jiangjin Yangtze River Bridge.

Zhang, Benniu; Wang, Shuliang; Li, Xingxing; Zhang, Xu; Yang, Guang; Qiu, Minfeng

2014-04-01

431

The effective theory of Borel equivalence relations  

DEFF Research Database (Denmark)

The study of Borel equivalence relations under Borel reducibility has developed into an important area of descriptive set theory. The dichotomies of Silver [20] and Harrington, Kechris and Louveau [6] show that with respect to Borel reducibility, any Borel equivalence relation strictly above equality on Ï? is above equality on P (Ï?), the power set of Ï?, and any Borel equivalence relation strictly above equality on the reals is above equality modulo finite on P (Ï?). In this article we examine the effective content of these and related results by studying effectively Borel equivalence relations under effectively Borel reducibility. The resulting structure is complex, even for equivalence relations with finitely many equivalence classes. However use of Kleene's O as a parameter is sufficient to restore the picture from the noneffective setting. A key lemma is that of the existence of two effectively Borel sets of reals, neither of which contains the range of the other under any effectively Borel function; the proof of this result applies Barwise compactness to a deep theorem of Harrington (see [5,16]) establishing for any recursive ordinal α the existence of Π singletons whose α-jumps are Turing incomparable. © 2009 Elsevier B.V. All rights reserved.

Fokina, E.B.; Friedman, S.-D.

2010-01-01

432

A Measurement of the Total Width, the Electronic Width and the Mass of the Upsilon(10580) Resonance  

CERN Document Server

We present a preliminary measurement of the resonance parameters of the Upsilon(10580) resonance with the BABAR detector at the SLAC PEP-II asymmetric B factory. We measure the total decay width to be (20.7 +- 1.6 +- 2.5) MeV, the partial electronic width to be (0.321 +- 0.017 +- 0.029) kev and the mass to be (10.5793 +- 0.0004 +- 0.0012) GeV.

Aubert, Bernard; Abe, T; Abrams, G S; Adye, T; Ahmed, S; Alam, M S; Albert, J; Aleksan, Roy; Allison, J; Altenburg, D; Andreotti, M; Angelini, C; Anulli, F; Aston, D; Azzolini, V; Baak, M A; Back, J J; Bailey, S; Baldini-Ferroli, R; Band, H R; Banerjee, Sw; Barate, R; Barlow, N R; Barlow, R J; Bartoldus, R; Batignani, G; Bauer, J M; Beck, T W; Behera, P K; Bellini, F; Benayoun, M; Berger, N; Beringer, J; Bernard, D; Berryhill, J W; Best, D; Bettarini, S; Bettoni, D; Bevan, A J; Bhimji, W; Bianchi, F; Biasini, M; Blanc, F; Blaylock, G; Blinov, V E; Bloom, P; Bondioli, M; Bonneaud, G R; Borean, C; Borgland, A W; Bosisio, L; Boutigny, D; Bowerman, D A; Boyarski, A M; Boyd, J T; Bozzi, C; Brandt, T; Brau, B; Brau, J E; Breon, A B; Briand, H; Brigljevic, V; Brochard, F; Brose, J; Brown, C L; Brown, C M; Brown, D; Brown, D N; Bruinsma, M; Brunet, S; Bucci, F; Buchanan, C; Buchmüller, O L; Bugg, W; Bukin, A D; Burchat, Patricia R; Button-Shafer, J; Buzzo, A; Bóna, M; Cahn, R N; Calabrese, R; Calcaterra, A; Calderini, G; Campagnari, C; Capra, R; Carpinelli, M; Cartaro, C; Cavallo, N; Cavoto, G; Chao, M; Charles, E; Chauveau, J; Chen, E; Chen, J C; Chen, S; Cheng, C H; Chevalier, N; Christ, S; Cibinetto, G; Clark, P J; Cochran, J; Cohen-Tanugi, J; Colberg, T; Colecchia, F; Coleman, J P; Contri, R; Convery, M R; Cote-Ahern, D; Cottingham, W N; Coupal, D P; Cowan, G; Cowan, R; Crawley, H B; Cremaldi, L M; Crosetti, G; Dahmes, B; Dallapiccola, C; Danielson, N; Dasu, S; Datta, M; Dauncey, P D; David, P; Davier, M; Davis, C L; Day, C T; De Groot, N; De Nardo, Gallieno; De Sangro, R; Del Buono, L; Del Gamba, V; Del Re, D; Della Ricca, G; Di Lodovico, F; Dickopp, M; Dittongo, S; Donald, M; Dong, D; Dorfan, J; Dorigo, A; Dubitzky, R S; Dubois-Felsmann, G P; Dujmic, D; Dunwoodie, W M; Dvoretskii, A; Eckmann, R; Edwards, A J; Egede, U; Eichenbaum, A M; Eigen, G; Eisner, A M; Elmer, P; Emery, S; Ernst, J A; Eschenburg, V; Eschrich, I; Fabozzi, F; Faccini, R; Falciai, D; Farbin, A; Ferrarotto, F; Ferroni, F; Field, R C; Finocchiaro, G; Fisher, A; Flack, R L; Flächer, H U; Flood, K T; Ford, K; Ford, W T; Forti, A C; Forti, F; Fortin, D; Franek, B J; Frey, R; Fry, J R; Gabathuler, Erwin; Gabriel, T A; Gaidot, A; Gaillard, J M; Gaillard, J R; Galeazzi, F; Gallo, F; Gamba, D; Gamet, R; Gan, K K; Ganzhur, S F; Gaspero, M; Gatto, C; Geddes, N I; George, S; Gill, M S; Giorgi, M A; Giraud, P F; Gladney, L; Glanzman, T; Godang, R; Goetzen, K; Golubev, V B; Gopal, G P; Gowdy, S J; Grancagnolo, S; Graugès-Pous, E; Green, M G; Grenier, G J; Grenier, P; Gritsan, A V; Grosdidier, G; Groysman, Y; Guo, Q H; Hadavand, H K; Hadig, T; Haire, M; Halyo, V; Hamel de Monchenault, G; Hamon, O; Harrison, P F; Harrison, T J; Hart, P A; Hartfiel, B L; Harton, J L; Hast, C; Hauke, A; Hawkes, C M; Hearty, C; Held, T; Hertzbach, S S; Heusch, C A; Hicheur, A; Hill, E J; Hitlin, D G; Hodgkinson, M C; Honscheid, K; Hrynóva, T; Hu, T; Hufnagel, D; Höcker, A; Innes, W R; Ivanchenko, V N; Izen, J M; Jackson, F; Jackson, P D; Jacobsen, R G; Jawahery, A; Jayatilleke, S M; Jessop, C P; John, M J J; Johnson, J R; Judd, D; Kadel, R W; Kadyk, J; Kagan, H; Karyotakis, Yu; Kass, R; Kay, M; Kelly, M P; Kelsey, M H; Kerth, L T; Khan, A; Kim, H; Kim, P; Kirkby, D; Kitayama, I; Knowles, D J; Koch, H; Kocian, M L; Kofler, R; Kolomensky, Yu G; Koptchev, V B; Kovalskyi, D; Kowalewski, R V; Kozanecki, Witold; Kral, J F; Kravchenko, E A; Krishnamurthy, M; Kroeger, R; Kukartsev, G; Kurup, A; Kutter, P E; Kuznetsova, N; Kyberd, P; La Vaissière, C de; Lacker, H M; Lae, C K; Lafferty, G D; Lamsa, J; Lanceri, L; Lange, D J; Langenegger, U; Langer, M; Lankford, A J; Laplace, S; Latham, T E; Lavin, D; Lazzaro, A; Le Clerc, C; Le Diberder, F R; Lee, S J; Lees, J P; Legendre, M; Leith, D W G S; Lepeltier, V; Leruste, P; Levesque, J A; Levi, M E; Levy, S L; Lewandowski, B; Li, H; Lillard, V; Lista, L; Liu, R; Lo Vetere, M; LoSecco, J M; Lockman, W S; London, G W; Long, O; Lou, X C; Lu, A; Luitz, S; Luppi, E; Lusiani, A; Lutz, A M; Lynch, G; Lynch, H L; Lyon, A J; Lü, C; Lüth, V; MacFarlane, D B; MacKay, C; Macri, M; Mallik, U; Maly, E; Mancinelli, G; Mandelkern, M A; Manfredi, P F; Mangeol, D J J; Marchiori, G; Margoni, M; Marker, C E; Marsiske, H; Martínez-Vidal, F; Mattison, T S; Mayer, B; Mazur, M A; Mazzoni, M A; McKemey, A K; McKenna, J A; McMahon, T R; Meadows, B T; Messner, R; Meyer, T I; Meyer, W T; Miftakov, V; Mihályi, A; Mir, L M; Mohapatra, A K; Mommsen, R K; Monge, M R; Moore, T B; Morandin, M; Morgan, S E; Morganti, M; Morganti, S; Morii, M; Morton, G W; Muheim, F; Müller, D R; Müller-Pfefferkorn, R; Narsky, I; Nash, J A; Nauenberg, U; Neal, H; Negrini, M; Neri, N; Nicholson, H; Nogowski, R; O'Grady, C P; Ocariz, J; Oddone, P J; Ofte, I; Olaiya, E O; Olivas, A; Olsen, J; Onuchin, A P; Orimoto, T J; Otto, S; Ozcan, V E; Paar, H P

2003-01-01

433

A large, multi-epoch H{\\alpha} survey at z=2.23, 1.47, 0.84 & 0.40: the 11 Gyr evolution of star-forming galaxies from HiZELS  

CERN Document Server

This paper presents new deep and wide narrow-band surveys undertaken with UKIRT, Subaru and the VLT; a unique combined effort to select large, robust samples of H-alpha (Ha) emitters at z=0.40, 0.84, 1.47 and 2.23 (corresponding to look-back times of 4.2, 7.0, 9.2 and 10.6 Gyrs) in a uniform manner over ~2 deg^2 in the COSMOS and UDS fields. The deep multi-epoch Ha surveys reach ~3M_sun/yr out to z=2.2 for the first time, while the wide area and the coverage over two independent fields allow to greatly overcome cosmic variance. A total of 1742, 637, 515 and 556 Ha emitters are homogeneously selected at z=0.40, 0.84, 1.47 and 2.23, respectively, and used to determine the Ha luminosity function and its evolution. The faint-end slope is found to be -1.60+-0.08 over z=0-2.23, showing no evolution. The characteristic luminosity of SF galaxies, L*, evolves significantly as log[L*(z)]=0.45z+log[L*(z=0)]. This is the first time Ha has been used to trace SF activity with a single homogeneous survey at z=0.4-2.23. Over...

Sobral, David; Best, Philip N; Geach, James E; Matsuda, Yuichi; Stott, John P; Cirasuolo, Michele; Kurk, Jaron

2012-01-01

434

The principle of equivalence reconsidered: assessing the relevance of the principle of equivalence in prison medicine.  

Science.gov (United States)

In this article we critically examine the principle of equivalence of care in prison medicine. First, we provide an overview of how the principle of equivalence is utilized in various national and international guidelines on health care provision to prisoners. Second, we outline some of the problems associated with its applications, and argue that the principle of equivalence should go beyond equivalence to access and include equivalence of outcomes. However, because of the particular context of the prison environment, third, we contend that the concept of "health" in equivalence of health outcomes needs conceptual clarity; otherwise, it fails to provide a threshold for healthy states among inmates. We accomplish this by examining common understandings of the concepts of health and disease. We conclude our article by showing why the conceptualization of diseases as clinical problems provides a helpful approach in the delivery of health care in prison. PMID:24978402

Jotterand, Fabrice; Wangmo, Tenzin

2014-07-01

435

Equivalent diffusion coefficient and equivalent diffusion accessible porosity of a stratified porous medium  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Diffusion is an important transport process in low permeability media, which play an important role in contamination and remediation of natural environments. The calculation of equivalent diffusion parameters has however not been extensively explored. In this paper, expressions of the equivalent diffusion coefficient and the equivalent diffusion accessible porosity normal to the layering in a layered porous medium are derived based on analytical solutions of the diffusion equation. The expres...

Huysmans, Marijke; Dassargues, Alain

2007-01-01

436

On the Equivalence of Quadratic APN Functions  

CERN Multimedia

Establishing the CCZ-equivalence of a pair of APN functions is generally quite difficult. In some cases, when seeking to show that a putative new infinite family of APN functions is CCZ inequivalent to an already known family, we rely on computer calculation for small values of n. In this paper we present a method to prove the inequivalence of quadratic APN functions with the Gold functions. Our main result is that a quadratic function is CCZ-equivalent to an APN Gold function if and only if it is EA-equivalent to that Gold function. As an application of this result, we prove that a trinomial family of APN functions that exist on finite fields of order 2^n where n = 2 mod 4 are CCZ inequivalent to the Gold functions. The proof relies on some knowledge of the automorphism group of a code associated with such a function.

Byrne, Eimear; McGuire, Gary; Nebe, Gabriele

2011-01-01

437

Equivalence and Isomorphism for Boolean Constraint Satisfaction  

CERN Document Server

A Boolean constraint satisfaction instance is a conjunction of constraint applications, where the allowed constraints are drawn from a fixed set B of Boolean functions. We consider the problem of determining whether two given constraint satisfaction instances are equivalent and prove a Dichotomy Theorem by showing that for all sets C of allowed constraints, this problem is either polynomial-time solvable or coNP-complete, and we give a simple criterion to determine which case holds. A more general problem addressed in this paper is the isomorphism problem, the problem of determining whether there exists a renaming of the variables that makes two given constraint satisfaction instances equivalent in the above sense. We prove that this problem is coNP-hard if the corresponding equivalence problem is coNP-hard, and polynomial-time many-one reducible to the graph isomorphism problem in all other cases.

Böhler, E; Reith, S; Vollmer, H; Reith, Steffen; Vollmer, Heribert

2002-01-01

438

System Equivalent for Real Time Digital Simulator  

Science.gov (United States)

The purpose of this research is to develop a method of making system equivalents for the Real Time Digital Simulator (RTDS), which should enhance its capability of simulating large power systems. The proposed equivalent combines a Frequency Dependent Network Equivalent (FDNE) for the high frequency electromagnetic transients and a Transient Stability Analysis (TSA) type simulation block for the electromechanical transients. The frequency dependent characteristic for FDNE is obtained by curve-fitting frequency domain admittance characteristics using the Vector Fitting method. An approach for approximating the frequency dependent characteristic of large power networks from readily available typical power-flow data is also introduced. A new scheme of incorporating TSA solution in RTDS is proposed. This report shows how the TSA algorithm can be adapted to a real time platform. The validity of this method is confirmed with examples, including the study of a multi in-feed HVDC system based network.

Lin, Xi

439

Rocking-curve width of sagittally bent Laue crystals.  

Science.gov (United States)

The use of bent asymmetric Laue crystals to sagittally focus high-energy synchrotron X-rays calls for an understanding of the mechanisms affecting X-ray diffraction by such crystals. The rocking-curve width, a measurable quantity directly related to the distortion of the lattice planes, is the necessary first step towards such an understanding. A model is formulated for assessing the rocking-curve widths of sagittally bent Laue crystals, considering the elastic anisotropy. A method for depth-resolved measurement of the rocking curves was also developed to verify the model. The model successfully explains the wide range of rocking-curve widths of a large number of reflections from silicon crystals with two different orientations. PMID:12192122

Zhong, Z; Kao, C C; Siddons, D P; Hastings, J B

2002-09-01

440

Modelling the widths of fission observables in GEF  

Directory of Open Access Journals (Sweden)

Full Text Available The widths of the mass distributions of the different fission channels are traced back to the probability distributions of the corresponding quantum oscillators that are coupled to the heat bath, which is formed by the intrinsic degrees of freedom of the fissioning system under the influence of pairing correlations and shell effects. Following conclusion from stochastic calculations of Adeev and Pashkevich, an early freezing due to dynamical effects is assumed. It is shown that the mass width of the fission channels in low-energy fission is strongly influenced by the zero-point motion of the corresponding quantum oscillator. The observed variation of the mass widths of the asymmetric fission channels with excitation energy is attributed to the energy-dependent properties of the heat bath and not to the population of excited states of the corresponding quantum oscillator.

Schmidt K.-H.

2013-03-01

First Page Previous Page 1 2 3 4 5 6 7 8 9