Analysis of Far-UV High Excitation Line Emission Detected in the Gravitational Lens Q0957+561 with IUE-NEWSIPS

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Session 12 -- Absorption Lines in QSOs
Display presentation, Wednesday, January 12, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[12.01] Analysis of Far-UV High Excitation Line Emission Detected in the Gravitational Lens Q0957+561 with IUE-NEWSIPS

A.G. Michalitsianos, S.P. Maran, D. Kazanas, Y. Kondo (NASA/GSFC), F.C. Bruhweiler (Catholic U.), J. Nichols-Bohlin, M. de la Pena, T. Meylan, M. Perez, R. Thompson (IUE OBS-CSC)

We have continued analysis of far-UV high excitation emission lines which were detected in the double lens quasar 0957+561 during test runs of the New Spectral Image Processing System (NEWSIPS) of data obtained from the International Ultraviolet Explorer (IUE) archive (Michalitsianos et al., ApJ. Lett., Nov. 10, 1993). The significant reduction of fixed-pattern background noise, and the use of a signal-weighted extraction slit, which was applied to 10 co-added LWP (2000-3200A) spectra, revealed the presence of emission lines of S VI 933,945A, C III 978A, N III 992A, S IV 1063-1073, N II 1084A, O VI 1031,1037A and Fe III(UV1;1125A), in addition to Ly-alpha 1215A and N V 1240A previously reported. These identifications assume rest wavelengths consistent with the z = 1.41 redshift of the lensed quasar. We also found strong Ly-beta 1020A absorption at a redshift consistent with a previously reported damped Ly-alpha system at z = 1.3911, which is probably associated with an intervening gas near the quasar. The strong discontinuity in the continuum at 912A is appropriate to absorption that corresponds to the Ly-alpha and Ly-beta absorption line system at a z = 1.3911. The expected far-UV emission lines strengths appropriate for a QSO (assuming solar elemental abundances) were calculated using the photo-ionization code CLOUDY, where we assumed a power-law synchrotron flux distribution with slopes that range from -0.5 to -1.5, and ionization and density parameters appropriate for the QSO broad line region. These results predict strong features that correspond to the emission lines identified here. The relative intensities of emission lines present in the lens images A and B were obtained to determine if gravitational lensing leads to flux variations of different ionic species, which sets constraints on the size of the quasar emitting regions.

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