Zobrazeno 61 - 70
of 3 504
pro vyhledávání: '"Dietrich, M."'
Autor:
El-Samad, S Abd, Bilger, R., Brinkmann, K. -Th., Clement, H., Dietrich, M., Doroshkevich, E., Dshemuchadse, S., Erhardt, A., Eyrich, W., Filippi, A., Freiesleben, H., Fritsch, M., Geyer, R., Gillitzer, A., Hauffe, J., Hesselbarth, D., Jaekel, R., Jakob, B., Karsch, L., Kilian, K., Koch, H., Kress, J., Kuhlmann, E., Marcello, S., Marwinski, S., Meier, R., Moeller, K., Morsch, H. P., Naumann, L., Roderburg, E., Schoenmeier, P., Schulte-Wissermann, M., Schroeder, W., Steinke, M., Stinzing, F., Sun, G. Y., Waechter, J., Wagner, G. J., Wagner, M., Weidlich, U., Wilms, A., Wirth, S., Zhang, G., Zupranski, P.
Publikováno v:
Eur.Phys.J. A30 (2006) 443-453
The single-pion production reactions $pp\to d\pi^+$, $pp\to np\pi^+$ and $pp\to pp\pi^0$ were measured at a beam momentum of 0.95 GeV/c ($T_p \approx$ 400 MeV) using the short version of the COSY-TOF spectrometer. The implementation of a central calo
Externí odkaz:
http://arxiv.org/abs/nucl-ex/0609011
We present the results of a long-term variability campaign of very broad-line AGNs with line widths broader than FWHM $>$ 5000 kms$^{-1}$. The main goal of our investigation was to study whether the widths of the optical broad emission lines are corr
Externí odkaz:
http://arxiv.org/abs/astro-ph/0604468
Publikováno v:
Astrophys.J. 623 (2005) 700-720
We present optical spectra and emission-line ratios of 12 Narrow-Line Seyfert 1 (NLS1) galaxies that we observed to study the ionizing EUV continuum. A common feature in the EUV continuum of active galactic nuclei is the big blue bump (BBB), generall
Externí odkaz:
http://arxiv.org/abs/astro-ph/0501483
Publikováno v:
Astrophys.J.596:817-829,2003
We present results of the analysis of near infrared spectroscopic observations of 6 high-redshift quasars (z > 4), emphasizing the measurement of the ultraviolet FeII/MgII emission line strength in order to estimate the beginning of intense star form
Externí odkaz:
http://arxiv.org/abs/astro-ph/0306584
High redshift quasars mark the locations where massive galaxies are rapidly being assembled and forming stars. There is growing evidence that quasar environments are metal-rich out to redshifts of at least five. The gas-phase metallicities are typica
Externí odkaz:
http://arxiv.org/abs/astro-ph/0306068
Autor:
Dietrich, M., Hamann, F., Shields, J. C., Constantin, A., Heidt, J., Jaeger, K., Vestergaard, M., Wagner, S. J.
Publikováno v:
Astrophys.J. 589 (2003) 722-732
We examine rest-frame ultraviolet spectra of 70 high redshift quasars (z>3.5) to study the chemical enrichment history of the gas closely related to the quasars, and thereby estimate the epoch of first star formation. The fluxes of several ultraviole
Externí odkaz:
http://arxiv.org/abs/astro-ph/0302494
Publikováno v:
Astrophys.J. 585 (2003) 121-127
We analyze published reverberation mapping data for three Seyfert galaxies (NGC 3227, NGC 3516, and NGC 4593) to refine the mass estimate for the supermassive black hole in the center of each object. Treatment of the data in a manner more consistent
Externí odkaz:
http://arxiv.org/abs/astro-ph/0212115
Autor:
Dietrich, M., Appenzeller, I., Hamann, F., Heidt, J., Jaeger, K., Vestergaard, M., Wagner, S. J.
Publikováno v:
Astron.Astrophys. 398 (2003) 891-900
We present observations of 11 high redshift quasars ($3.9 \la z \la 5.0$) observed with low spectral resolution in the restframe ultraviolet using FORS 1 at the VLT UT 1. The emission-line fluxes of strong permitted and intercombination ultraviolet e
Externí odkaz:
http://arxiv.org/abs/astro-ph/0211466
Publikováno v:
Astrophys.J. 583 (2003) 649-658
The intensity of the strong N V 1240 line relative to C IV 1549 or to He II 1640 has been proposed as an indicator of the metallicity of QSO broad emission line regions, allowing abundance measurements in a large number of QSOs out to the highest red
Externí odkaz:
http://arxiv.org/abs/astro-ph/0210153
Autor:
Shields, G. A., Gebhardt, K., Salviander, S., Wills, B. J., Xie, B., Brotherton, M. S., Yuan, J., Dietrich, M.
Publikováno v:
Astrophys.J.583:124-133,2003
We use QSO emission-line widths to examine the black hole mass - sigma relationship as a function of redshift and to extend the relationship to larger masses. Supermassive black holes in galactic nuclei are closely related to the bulge of the host ga
Externí odkaz:
http://arxiv.org/abs/astro-ph/0210050