Absorption Lines in the Spectra of the QSO PKS 1448-232

1984 ◽  
Vol 5 (3) ◽  
pp. 355-359 ◽  
Author(s):  
Chen Jian-sheng ◽  
Donald C. Morton ◽  
Bruce A. Peterson ◽  
Alan E. Wright ◽  
David L. Jauncey
Keyword(s):  
Radio Source ◽  
Stellar Object ◽  
Absorption Lines ◽  
Ultraviolet Excess ◽  
Low Resolution ◽  
Optical Position

Savage et al. (1977) found that the radio source PKS 1448-232 coincided with a stellar object of about magnitude 16.4 having an ultraviolet excess. A low resolution spectrum obtained with the Anglo-Australian Telescope (AAT) confirmed this object as a QSO with zem = 2.22 and revealed many absorption lines short-ward of the La emission. Consequently this object was included in a programme of spectroscopy at intermediate resolution with the AAT to investigate QSO absorption lines. Savage et al. have given a finding chart with an optical position of 14h48m09s.3, −23°17′10″ (1950.0). The radio fluxes are 0.40 Jy at 2.7 GHz and 0.31 Jy at 5.0 GHz.

The origin of the quasi-stellar object absorption lines

1991 ◽  
Vol 377 ◽  
pp. 39 ◽  
Author(s):  
S. M. Viegas ◽  
R. B. Gruenwald
Keyword(s):  
Stellar Object ◽  
Absorption Lines

A Subarcsecond Binary Radio Source Associated with the X-Ray–Emitting Young Stellar Object YLW 15

2000 ◽  
Vol 544 (2) ◽  
pp. L153-L156 ◽  
Author(s):  
José M. Girart ◽  
Luis F. Rodríguez ◽  
Salvador Curiel
Keyword(s):  
Radio Source ◽  
Stellar Object ◽  
X Ray ◽  
Young Stellar Object

scholarly journals The Redshift Evolution of CIV in Galaxy Halos

1996 ◽  
Vol 171 ◽  
pp. 447-447
Author(s):  
E. A. Stengler Larrea
Keyword(s):  
Survival Analysis ◽  
Density Distribution ◽  
Absorption Lines ◽  
Number Density ◽  
Low Resolution ◽  
Redshift Distribution ◽  
Profile Fitting ◽  
Galaxy Halos ◽  
Lower Limits

Improved and reliable profile fitting codes have made it recently possible to calculate reliable column densities of gas producing QSO absorption lines. Even using intermediate to low resolution spectra, the obtained column densities are very accurate, as has been extensively proved by Jenkins (1986). We applied this technique to the 131 CIV absorption systems in the survey by Sargent Boksenberg and Steidel (1988) and Steidel (1990). Since several lines were saturated, many CIV column densities, N(CIV), are only lower limits, and a survival analysis (Avni et al. 1980) is required to obtain the underlying redshift distribution of CIV column densities, which we present in Figure 1. Together with the number density distribution of strong (log N(CIV) ≥ 14.2) and weak systems shown in Figure 2, we have found that i. Both strong and weak systems become generally weaker below z ∼ 2, and II. Weak systems become less numerous below z ∼ 2, whereas the stronger systems grow steadily in number density down the lowest redshifts sampled. For details of the analysis, and on how this fits into a model for the CIV absorption systems see Stengler-Larrea et al. (1995, in preparation).

High‐Resolution Spectra of Intrinsic Absorption Lines in the Quasi‐stellar Object UM 675

1997 ◽  
Vol 478 (1) ◽  
pp. 80-86 ◽  
Author(s):  
Fred Hamann ◽  
Thomas A. Barlow ◽  
Vesa Junkkarinen ◽  
E. M. Burbidge
Keyword(s):  
High Resolution ◽  
Stellar Object ◽  
Absorption Lines ◽  
Intrinsic Absorption

scholarly journals Accurate Optical Positions for Radio Source Identifications

1994 ◽  
Vol 47 (5) ◽  
pp. 657 ◽  
Author(s):  
Richard W Hunstead
Keyword(s):  
Radio Source ◽  
Southern Hemisphere ◽  
Radio Sources ◽  
Position Measurement ◽  
Optical Identification ◽  
Optical Position ◽  
Optical Identifications

The optical identification of strong radio sources was a key step in establishing a grid of southern hemisphere calibrators, both for Parkes and for Molonglo. However, the measurement of precise positions for these optical counterparts presented some special astrometric problems and led to some novel solutions. This paper summarises the progress of optical position measurement from a radio astronomer's viewpoint and examines the role of the COSMOS database against this background. The source 0007-44, from the first Parkes catalogue, is used as a case study to illustrate the present-day approach to optical identifications.

scholarly journals Ultraviolet Fe II Absorption Lines in HD 59643

1988 ◽  
Vol 103 ◽  
pp. 25-26
Author(s):  
Joel A. Eaton
Keyword(s):  
Emission Lines ◽  
Absorption Lines ◽  
Low Resolution ◽  
Composite Spectrum ◽  
The Common ◽  
Red Giant

AbstractThe peculiar red giant HD 59643 (C6,2) has a composite spectrum like a symbiotic star’s except for the absence of highly ionized species. UV observations show a highly variable hot continuum with superimposed absorptions of Fe II and the common emission lines of C IV, Si III], C III], C II], and Mg II. These Fe II absorptions, which are practically ubiquitous in interacting binaries, are an effective diagnostic of turbulence and distribution of scattering gas, even at low resolution.

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