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J/AJ/106/848      QSO MgII absorption line systems          (Drinkwater+, 1993)

On the nature of Mg II absorption line systems in quasars Drinkwater M.J., Webster R.L., Thomas P.A. <Astron. J. 106, 848 (1993)> =1993AJ....106..848D (SIMBAD/NED Reference)
ADC_Keywords: QSOs; Photometry, infrared; Combined data Abstract: The results of a large R-band imaging survey of 71 bright (m(V)<18) quasars are presented. The quasars were chosen from published samples which have intermediate resolution optical spectroscopy available, so the presence of low redshift Mg II absorption lines can be determined. We have searched our data for galaxies close to the line-of-sight to the quasars, which we might be able to identify with the absorption systems. We find a high coincidence between galaxies very near the line-of-sight and quasars showing absorption systems in their spectra, a result consistent with other studies. These galaxies have a mean luminosity of 0.5Lstar (assuming they lie at the absorption redshift). The distribution of impact parameters between the galaxies and the quasars extends with a flat distribution to large radii (>30h-1kpc). This suggests that the absorption systems may not be gravitationally bound to the observed galaxies, but may be part of larger extended systems. We also find a significant number of galaxies near the line-of-sight to the quasar where no absorption is seen in the quasar spectrum. The selection of our quasars is unbiased with respect to galaxies near the line-of-sight, so we can compare the observed number of absorption systems to that predicted by a simple model with a constant covering factor in Mg II absorbing gas within a maximum radius of each detected galaxy. The model is consistent with a covering factor of unity, but allowing for incompleteness in the detection of galaxies, the covering factor is less than unity. The redshifts of the galaxies are required to confirm this result. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1 118 71 Quasars observed table3a 28 70 Quasar parameters table3b 52 399 Catalogue of quasar companions
Byte-by-byte Description of file: table1
Bytes Format Units Label Explanations
1- 8 A8 --- QSO Quasar name 10- 12 A3 --- Type [RXCO ] Detection technique (1) 14- 15 I2 h RAh Right ascension 1950.0 17- 18 I2 min RAm Right ascension 1950.0 20- 24 F5.2 s RAs Right ascension 1950.0 26 A1 --- DE- Declination sign 27- 28 I2 deg DEd Declination 1950.0 30- 31 I2 arcmin DEm Declination 1950.0 33- 36 F4.1 arcsec DEs Declination 1950.0 38- 42 F5.2 mag Vmag Quasar V magnitude 44- 48 F5.3 --- z Quasar redshift (Data in bytes 1-48 taken from Hewitt & Burbidge 1987, ApJS, 63, 1, and Hewitt & Burbidge 1989, ApJS, 69, 1) 50- 53 F4.2 --- z1 Minimum redshift at which Mg II might be observed in the published spectra 55- 58 F4.2 --- z2 Maximum redshift at which Mg II might be observed in the published spectra 60- 65 F6.4 --- zab1 []? Redshift of any Mg II absorption systems 67- 72 F6.4 --- zab2 []? Redshift of any Mg II absorption systems 74- 82 A9 --- r_z Reference for the published spectra, parentheses signifying a non-detection (2) 84- 91 A8 "DD/MM/YY" Date Date observed (UT) 93- 96 I4 s Epx.T Exposure time 98-101 F4.2 arcsec FWHM FWHM seeing 103-107 F5.2 mag Rmag Quasar R magnitude 109-110 A2 --- Note Photometry flag (3) 114-118 F5.2 mag Rmagl Limiting R magnitude of image (the magnitude of the faintest object for which the formal error in the magnitude was less than 0.2 mag)
Note (1): C = color; O = spectral survey; R = radio; X = X-ray Note (2): References for published spectra |Number| W(rest) | Reference | | 0.1nm ----------------------------------------------------- | 1 | ∼ 0.5 | Weyman, et al. 1979, ApJ, 234, 33 | 1a | ∼ 0.8 | Weyman, et al. 1979, ApJ, 234, 33 | 2 | 0.6 | Young, et al. 1982, ApJS, 48, 455 | 3 | 0.5 | Foltz, et al. 1986, ApJ, 307, 504 | 4 | | Boulade, et al. 1987, in High Redshift and Primeval | | | Galaxies, edited by J. Bergeron et al. | | (Editions Frontieres, France), p. 349 | 5 | | Miller, et al. 1987, AJ, 94, 633 | 6 | ∼ 0.4 | Tytler, et al. 1987, ApJS, 64, 667 | 7 | 0.3 | Sargent, et al. 1988, AJ, 334, 22 | 8 | ∼ 0.5 | Bergeron & Boisse 1991, A&A, 243, 344 | 9 | 0.3 | Steidel & Sargent 1992, ApJS, 80, 1 |10 | 0.3 | Bechtold & Ellingson 1992, ApJ, 396, 20 |10a | 0.6 | Bechtold & Ellingson 1992, ApJ, 396, 20 Note (3): blank: photometric X: not photometric D: double image with magnitude from small DAOPHOT e: no small DAOPHOT fitting was possible
Byte-by-byte Description of file: table3a
Bytes Format Units Label Explanations
1- 12 A12 --- QSO Quasar name 14- 18 F5.3 --- z Quasar redshift 20- 22 F3.1 arcsec Seeing Seeing 24- 28 F5.2 mag Mlim Magnitude limit
Byte-by-byte Description of file: table3b
Bytes Format Units Label Explanations
1- 12 A12 --- QSO Quasar name 15- 19 F5.1 arcsec dRA Rigth ascension offset from the quasar 21- 25 F5.1 arcsec dDE Declination offset from the quasar 28- 31 F4.1 arcsec Dist Distance from the quasar 33- 34 A2 --- cls [fgs ] Classification (f: faint, g: galaxy, s: star) 36- 40 F5.2 mag Rmag Apparent R magnitude, m(R) 42- 45 F4.2 mag e_Rmag Formal photometry error in the magnitude 47- 52 F6.2 deg PA Position angle of the object with respect to the quasar, measured anti-clockwise from North
Origin: AAS CD-ROM series, Volume 1, 1993
(End) Patricia Bauer [CDS] 07-Sep-1994
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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