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355 results on '"BALMER line"'

52. Numerical and Experimental Study of Atomic Transport and Balmer Line Intensity in Linac4 Negative Ion Source.

Author

Shibata, T., Mattei, S., Nishida, K., Lettry, J., and Hatayama, A.

Subjects
*NUMERICAL analysis, *BALMER line, *ION sources, *COMPUTER simulation, *PHOTOMETRY
Abstract

Time structure of Balmer Hα line intensity in Linac4 RF plasma has been analyzed by the combined simulation model of atomic transport and Collisional-Radiative models. As a preliminary result, time variation of the line intensity in the ignition phase of RF plasma is calculated and compared with the experimental results by photometry. For the comparison, spatial distribution of the local Hα photon emission rate at each time is calculated from the numerical model. The contribution of the local photon emission rates to the observed line intensity via optical viewing port is also investigated by application of the mock-up of the optical viewing port and the known light source. It has been clarified from the analyses that the higher and the lower peaks of the Hα line intensity observed during 1 RF cycle is mainly due to the different spatial distributions in the electron energy distribution function and the resultant local photon emission rate. These results support previous suggestion that the existence of the capacitive electric field in axial direction leads to the higher/lower peaks of the line intensity. [ABSTRACT FROM AUTHOR]

Published
2015
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53. Interacting supernovae and supernova impostors: evidence of incoming supernova explosions?

Author

Tartaglia, L.

Subjects
*SUPERNOVAE, *LUMINOUS blue variables, *SPECTRUM analysis, *BALMER line, *COMPARATIVE studies
Abstract

Violent eruptions, and consequently major mass loss, are a common feature of the so-called Luminous Blue Variable (LBV) stars. During major eruptive episodes LBVs mimic the behavior of real type IIn supernovae (SNe), showing comparable radiated energy and similar spectroscopic properties. For this reason these events are frequently labelled as SN impostors. Type IIn SN spectra are characterized by the presence of prominent narrow Balmer lines in emission. In most cases, SNe IIn arise from massive stars (M>8⊙) exploding in a dense H-rich circumstellar medium (CSM), produced by progenitor's mass loss prior to the SN explosion. Although the mechanisms triggering these eruptions are still unknown, recently we had direct proofs of the connection between very massive stars, their eruptions and ejecta-CSM interacting SNe. SNe 2006jc, 2010mc, 2011ht and the controversial SN 2009ip are famous cases in which we observed the explosion of the star months to years after major outbursts. In this context, the case of a recent transient event, LSQ13zm, is extremely interesting since we observed an outburst just ~3 weeks before the terminal SN explosion. All of this may suggest that SN impostors occasionally herald true SN explosions. Nonetheless, there are several cases where major eruptions are followed by a quiescent phase in the LBV life. The impostor SN 2007sv is one of these cases, since it showed a single outburst event. Its photometric (a relatively faint absolute magnitude at the maximum) and spectroscopic properties (low velocity and temperature of the ejecta, and the absence of the typical elements produced in the explosive nucleosynthesis) strongly suggest that SN 2007sv was the giant eruption of an LBV, which has then returned in a quiescent stage. [ABSTRACT FROM AUTHOR]

Published
2015
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56. WFPC2 Observations of Procyon B

Author

Provencal, J. L., Shipman, H. L., Wesemael, F., Bergeron, P., Bond, H. E., Liebert, James, Sion, E. M., Isern, J., editor, Hernanz, M., editor, and García-Berro, E., editor

Published
1997
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62. Extreme ultraviolet spectroscopy of white dwarfs

Author

Barstow, M. A., Holberg, J. B., Koester, D., Nousek, J. A., Werner, K., Araki, H., editor, Brézin, E., editor, Ehlers, J., editor, Frisch, U., editor, Hepp, K., editor, Jaffe, R. L., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Wess, J., editor, Zittartz, J., editor, Beiglböck, W., editor, Koester, Detlev, editor, and Werner, Klaus, editor

Published
1995
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63. The mass distribution of DA white dwarfs

Author

Finley, David S., Araki, H., editor, Brézin, E., editor, Ehlers, J., editor, Frisch, U., editor, Hepp, K., editor, Jaffe, R. L., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Wess, J., editor, Zittartz, J., editor, Beiglböck, W., editor, Koester, Detlev, editor, and Werner, Klaus, editor

Published
1995
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64. The mass distribution and luminosity function of hot DA white dwarfs

Author

Liebert, J., Bergeron, P., Araki, H., editor, Brézin, E., editor, Ehlers, J., editor, Frisch, U., editor, Hepp, K., editor, Jaffe, R. L., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Wess, J., editor, Zittartz, J., editor, Beiglböck, W., editor, Koester, Detlev, editor, and Werner, Klaus, editor

Published
1995
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74. R40: first luminous blue variable in the small magellanic cloud

Author

Szeifert, Th., Stahl, O., Wolf, B., Zickgraf, F. J., Araki, H., editor, Brézin, E., editor, Ehlers, J., editor, Frisch, U., editor, Hepp, K., editor, Jaffe, R.L., editor, Kippenhahn, R., editor, Weidenmüller, H.A., editor, Wess, J., editor, Zittartz, J., editor, Beiglböck, W., editor, Baschek, Bodo, editor, Klare, Gerhard, editor, and Lequeux, James, editor

Published
1993
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75. The location of the dust causing internal reddening of active galactic nuclei.

Author

Heard, Clio Z. P. and Gaskell, C. Martin

Subjects
*ACTIVE galactic nuclei, *ACTIVE galaxies, *BALMER line, *HYDROGEN spectral lines, *ACCRETION (Astrophysics)
Abstract

We use the Balmer decrements of the broad-line regions (BLRs) and narrow-line regions (NLRs) of active galactic nuclei (AGNs) as reddening indicators to investigate the location of the dust for four samples of AGNs with reliable estimates of the NLR contribution to the Balmer lines. Intercomparison of the NLR and BLR Balmer decrements indicates that the reddening of the NLR sets a lower limit to the reddening of the BLR. Almost no objects have high NLR reddening but low BLR reddening. The reddening of the BLR is often substantially greater than the reddening of the NLR. The BLR reddening is correlated with the equivalent widths of [O III] lines and the intensity of the [O III] lines relative to broad Hβ. We find these relationships to be consistent with the predictions of a simple model where the additional dust reddening the BLR is interior to the NLR. We thus conclude that the dust causing the additional reddening of the accretion disc and BLR is mostly located at a smaller radius than the NLR. [ABSTRACT FROM AUTHOR]

Published
2016
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76. The detection and X-ray view of the changing look AGN HE 1136-2304.

Author

Parker, M. L., Komossa, S., Kollatschny, W., Walton, D. J., Schartel, N., antos-Lleó, M., Harrison, F. A., Fabian, A. C., Zetz, M., Grupe, D., Rodríguez-Pascual, P. M., and Vasudevan, R. V.

Subjects
*X-ray detection, *BALMER line, *SEYFERT galaxies, *OPTICAL spectroscopy, *ACCRETION disks, *BLACK holes
Abstract

We report the detection of high-amplitude X-ray flaring of the AGN HE 1136-2304, which is accompanied by a strong increase in the flux of the broad Balmer lines, changing its Seyfert type from almost type 2 in 1993 down to 1.5 in 2014. HE 1136-2304 was detected by the XMM-Newton slew survey at >10 times the flux it had in the ROSAT all-sky survey, and confirmed with Swift follow-up after increasing in X-ray flux by a factor of ~30. Optical spectroscopy with SALT shows that the AGN has changed from a Seyfert 1.95 to a Seyfert 1.5 galaxy, with greatly increased broad line emission and an increase in blue continuum AGN flux by a factor of >4. The X-ray spectra from XMM-Newton and NuSTAR reveal moderate intrinsic absorption and a high energy cutoff at ~100 keV. We consider several different physical scenarios for a flare, such as changes in obscuring material, tidal disruption events, and an increase in the accretion rate. We find that the most likely cause of the increased flux is an increase in the accretion rate, although it could also be due to a change in obscuration. [ABSTRACT FROM AUTHOR]

Published
2016
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78. Multi-site spectroscopic networks for the study of late-type stars

Author

MUSICOS team, Foing, Bernard H., Araki, H., editor, Brézin, E., editor, Ehlers, J., editor, Frisch, U., editor, Hepp, K., editor, Jaffe, R. L., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Wess, J., editor, Zittartz, J., editor, Beiglböck, W., editor, Byrne, Patrick B., editor, and Mullan, Dermott J., editor

Published
1992
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80. The atmospheres of extreme helium stars

Author

Simon Jeffery, C., Araki, H., editor, Brézin, E., editor, Ehlers, J., editor, Frisch, U., editor, Hepp, K., editor, Jaffe, R. L., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Wess, J., editor, Zittartz, J., editor, Beiglböck, W., editor, Heber, U., editor, and Jeffery, C. Simon, editor

Published
1992
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81. Analyses of B-type stars in the Magellanic Clouds

Author

Jüttner, A., Wolf, B., Araki, H., editor, Brézin, E., editor, Ehlers, J., editor, Frisch, U., editor, Hepp, K., editor, Jaffe, R. L., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Wess, J., editor, Zittartz, J., editor, Beiglböck, W., editor, Heber, U., editor, and Jeffery, C. Simon, editor

Published
1992
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82. Stellar flares: Confined or eruptive events?

Author

Pallavicini, R., Araki, H., editor, Breézin, E., editor, Ehlers, J., editor, Frisch, U., editor, Hepp, K., editor, Jaffe, R. L., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Wess, J., editor, Zittartz, J., editor, Beiglböck, W., editor, Švestka, Zdeněk, editor, Jackson, Bernard V., editor, and Machado, Marcos E., editor

Published
1992
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83. The Hydrogen Spectrum

Author

Sobelman, Igor I., Toennies, J. Peter, editor, Lotsch, Helmut K. V., editor, Ecker, Günter, editor, Lambropoulos, Peter, editor, Sobelman, Igor I., editor, and Walther, Herbert, editor

Published
1992
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84. A table of Balmer γ line shapes for the diagnostic of magnetic fusion plasmas.

Author

Rosato, J., Bufferand, H., Koubiti, M., Marandet, Y., and Stamm, R.

Subjects
*BALMER line, *STARK effect, *MAGNETIC spectrometer, *ZEEMAN effect, *TOKAMAKS
Abstract

Spectral profiles of the D γ line have been calculated in magnetic fusion plasma conditions for diagnostic purposes. This paper reports on the elaboration of a table devoted to spectroscopic applications in tokamak divertors. An overview of the method, together with the physics underlying the broadening of spectral lines, is given. A special emphasis is put on the role of the simultaneous action of the Stark and Zeeman effects. [ABSTRACT FROM AUTHOR]

Published
2015
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89. The DBAQ G35–26

Author

Thejll, Peter, MacDonald, James, Shipman, Harry L., Vauclair, Gérard, editor, and Sion, Edward, editor

Published
1991
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93. The Doppler Effect

Author

Schlosser, W., Schmidt-Kaler, T., Milone, E. F., Schlosser, W., Schmidt-Kaler, T., and Milone, E. F.

Published
1991
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94. Spectral Analysis

Author

Schlosser, W., Schmidt-Kaler, T., Milone, E. F., Schlosser, W., Schmidt-Kaler, T., and Milone, E. F.

Published
1991
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95. High-resolution spectroscopy of stellar winds in recently recognized LBV candidates

Author

Miroshnichenko, Anatoly S., Chentsov, Eugene L., Klochkova, Valentina G., Beig, R., editor, Ehlers, J., editor, Frisch, U., editor, Hepp, K., editor, Jaffe, R. L., editor, Kippenhahn, R., editor, Ojima, I., editor, Weidenmüller, H. A., editor, Wess, J., editor, Zittartz, J., editor, Beiglböck, W., editor, Eisenächer, Monika, editor, Wolf, Bernhard, editor, Stahl, Otmar, editor, and Fullerton, Alex W., editor

Published
1999
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