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Articles 1 - 5 of 5
Full-Text Articles in Physical Sciences and Mathematics
The Flaring H2o Megamaser And Compact Radio Source In Markarian 348, A. B. Peck, C. Henkel, J. S. Ulvestad, A. Brunthaler, H. Falcke, Moshe Elitzur, K. M. Menten, J. F. Gallimore
The Flaring H2o Megamaser And Compact Radio Source In Markarian 348, A. B. Peck, C. Henkel, J. S. Ulvestad, A. Brunthaler, H. Falcke, Moshe Elitzur, K. M. Menten, J. F. Gallimore
Physics and Astronomy Faculty Publications
We report on single-dish monitoring and extremely high angular resolution observations of the flaring H2O megamaser in the Seyfert 2 galaxy Mrk 348. The H2O line is redshifted by ~130 km s-1 with respect to the systemic velocity, is very broad, with an FWHM of 130 km s-1, and has no detectable high-velocity components within 1500 km s-1 on either side of the strong line. Monitoring observations made with the Effelsberg 100 m telescope show that the maser varies significantly on timescales as short as 1 day and that the integrated line …
Chemical Abundances In Broad Emission Line Regions: The "Nitrogen-Loud'' Quasi-Stellar Object Q0353-383, J. A. Baldwin, F. Hamann, K. T. Korista, Gary J. Ferland, M. Dietrich, C. Warner
Chemical Abundances In Broad Emission Line Regions: The "Nitrogen-Loud'' Quasi-Stellar Object Q0353-383, J. A. Baldwin, F. Hamann, K. T. Korista, Gary J. Ferland, M. Dietrich, C. Warner
Physics and Astronomy Faculty Publications
The intensity of the strong N V λ1240 line relative to C IV λ1549 or to He II λ1640 has been proposed as an indicator of the metallicity of quasi-stellar object (QSO) broad emission line regions, allowing abundance measurements in a large number of QSOs out to the highest redshifts. Previously, it had been shown that the (normally) much weaker lines N III] λ1750 and N IV] λ1486 could be used in the same way. The redshift 1.96 QSO 0353-383 has long been known to have N III] and N IV] lines that are far stronger relative to Lyα or …
The Mass Of Quasar Broad Emission Line Regions, J. A. Baldwin, Gary J. Ferland, K. T. Korista, F. Hamann, M. Dietrich
The Mass Of Quasar Broad Emission Line Regions, J. A. Baldwin, Gary J. Ferland, K. T. Korista, F. Hamann, M. Dietrich
Physics and Astronomy Faculty Publications
We show that the mass of ionized gas in the broad-line regions (BLRs) of luminous quasars is at least several hundred M☉, and probably of the order of 103-104 Msolar. BLR mass estimates in several existing textbooks suggest lower values but pertain to much less luminous Seyfert galaxies or include only a small fraction of the ionized/emitting volume of the BLR. The previous estimates also fail to include the large amounts of BLR gas that emit at low efficiency (in a given line) but that must be present based on reverberation and other …
Temperature Variations From Hubble Space Telescope Spectroscopy Of The Orion Nebula, R. H. Rubin, P. G. Martin, R. J. Dufour, Gary J. Ferland, K. P. M. Blagrave, X.-W. Liu, J. F. Nguyen, J. A. Baldwin
Temperature Variations From Hubble Space Telescope Spectroscopy Of The Orion Nebula, R. H. Rubin, P. G. Martin, R. J. Dufour, Gary J. Ferland, K. P. M. Blagrave, X.-W. Liu, J. F. Nguyen, J. A. Baldwin
Physics and Astronomy Faculty Publications
We present Hubble Space Telescope (HST)/STIS long-slit spectroscopy of NGC 1976. Our goal is to measure the intrinsic line ratio [O III] 4364/5008 and thereby evaluate the electron temperature (Te) and the fractional mean-square Te variation (t2A)across the nebula. We also measure the intrinsic line ratio [N II] 5756/6585 in order to estimate Te and t2A in the N+region. The interpretation of the [N II] data is not as clear cut as the [O III] data because of a higher sensitivity to knowledge …
Inner-Shell Photoexcitation Of Fe Xv And Fe Xvi, R. Kisielius, A. Hibbert, Gary J. Ferland, M. E. Foord, S. J. Rose, P. A. M. Vanhoof, F. P. Keenan
Inner-Shell Photoexcitation Of Fe Xv And Fe Xvi, R. Kisielius, A. Hibbert, Gary J. Ferland, M. E. Foord, S. J. Rose, P. A. M. Vanhoof, F. P. Keenan
Physics and Astronomy Faculty Publications
The configuration-interaction method as implemented in the computer code CIV3 is used to determine energy levels, electric dipole radiative transition wavelengths, oscillator strengths and transition probabilities for inner-shell excitation of transitions in Fe XV and Fe XVI. Specifically, transitions are considered of the type 1s22s22p63s2–1s22s22p53l3l′3l′′ (l, l′ and l′′= s, p or d) in Fe XV and 1s22s22p63s–1s22s22p53l3l′ (l …