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J/ApJ/571/665       Analysis of the Lyα forest at z=0-5. V. (Scott+, 2002)
A uniform analysis of the Lyα forest at z=0-5.
V. The extragalactic ionizing background at low redshift.
    Scott J., Bechtold J., Morita M., Dobrzycki A., Kulkarni V.P.
   <Astrophys. J. 571, 665 (2002)>
   =2002ApJ...571..665S
ADC_Keywords: QSOs ; Spectroscopy

Keywords: diffuse radiation - intergalactic medium - quasars: absorption lines


Abstract:
    In Paper III (Bechtlod et al., 2002, Cat. J/ApJS/140/143) of our
    series, "A Uniform Analysis of the Lyα Forest at z=0-5", we
    presented a set of 270 quasar spectra from the archives of the Faint
    Object Spectrograph (FOS) on the Hubble Space Telescope (HST). A total
    of 151 of these spectra, yielding 906 lines, are suitable for using
    the proximity effect signature to measure J(ν0), the mean
    intensity of the hydrogen-ionizing background radiation field, at low
    redshift.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table1.dat        86      178   Sample QSOs and Emission Line Redshifts
table3.dat        81      178   Spectrophotometric Properties
refs.dat          79       49   Redshift references
spectra/*          0       37   Figures containing the spectra


See also:
     J/ApJS/140/143 : Analysis of the Lyα forest at z=0-5. III


Byte-by-byte Description of file: table1.dat

   Bytes Format Units   Label     Explanations

   1- 10  A10   ---     QSO       QSO name (1)
      12  A1    ---     f_QSO     [3] Indicates observed only with
                                  pre-COSTAR FOS and A-1 aperture
  14- 32  A19   ---     NEDdsc    NED description
      34  A1    ---     f_NEDdsc  Flag on NED description (2)
  36- 41  F6.4  ---     zLya      ? Redshift from the Ly-α line
      43  A1    ---     n_zLya    [KGHF] Note on zLya (3)
  45- 50  F6.4  ---     zMgII     ? Redshift from the Mg II line
  52- 57  F6.4  ---     zOIII     ? Redshift from the [O III] line
  59- 64  F6.4  ---     zBalmer   ? Redshift from the Balmer lines
  66- 67  I2    ---     r_zLya    ? Reference for zLya, in refs.dat file
  69- 70  I2    ---     r_zMgII   ? Reference for zMgII, in refs.dat file
  72- 73  I2    ---     r_zOIII   ? Reference for zOIII, in refs.dat file
  75- 76  I2    ---    r_zBalmer  ? Reference for zBalmer, in refs.dat file
  79- 86  A8    ---     figFile   File with figure in "spectra" subdirectory.

Note (1): See Paper III, Table 1 for alternate names.

Note (2): Flag on NEDdsc:
     2 = We classify this as an associated absorber, see Paper III,
          Bechtlod et al., 2002ApJS..140..143B.
     5 = Classified as blazar by Kinney et al. (1991ApJS...75..645K).
Note (3): Redshift reference, when only one redshift:
     K = Knezek & Bregman, 1998AJ....115.1737K
     G = Green et al., 1986, Cat. II/207
     H = Hewitt & Burbidge, 1987ApJS...63....1H
     F = Falomo et al., 1993ApJ...411L..63F


Byte-by-byte Description of file: table3.dat

   Bytes Format Units      Label     Explanations

   1- 10  A10   ---        QSO       QSO Name
  12- 16  A5    ---        f_QSO     Flag on QSO (1)
  18- 22  F5.2  10+20/cm2  NHI       Hydrogen column density (2)
  24- 27  F4.2  uJy        FObs      ? Direct measurement of flux at Lyman Limit
  29- 33  F5.2  ---        Sp-Index  ? Measured spectral index
  35- 39  F5.2  ---      e_Sp-Index  ? Uncertainty in Sp-Index
  41- 45  F5.2  uJy        FExt      ? Extrapolated flux at Lyman Limit
  47- 51  F5.3  uJy        e_FExt    ? Uncertainty in FExt
  53- 57  F5.2  uJy        FRest     ? Measured flux at the rest wavelength
                                        lambda
  59- 62  I4    0.1nm      lambda    ? Wavelength where FRest is measured
                                        in Angstroems
  64- 68  F5.2  [-]        RL        ? Radio Loudness (3)
  70- 71  I2    ---        r_FObs    ? Reference on FObs, in refs.dat file
  73- 74  A2    ---      r_Sp-Index  Reference on Sp-Index, in refs.dat file
  76- 77  A2    ---        r_FExt    Reference on FExt, in refs.dat file
  79- 80  A2    ---        r_FRest   Reference on FRest, in refs.dat file

Note (1): Notes on QSO:
     1 = Object spectrum shows associated absorption;
     2 = Observed only with pre-COSTAR FOS and A-1 aperture, not used for
         proximity effect;
     3 = Object is classified as a blazar or BL Lac;
     4 = Flux estimated from scaling composite QSO spectrum to match V;
     5 = Object spectrum shows damped Ly-α absorption;
     6 = No Ly-α forest observed, not used for proximity effect;
     7 = Binary quasar, not used for proximity effect;
     8 = Flux estimated from scaling composite QSO spectrum to match B
Note (2): From Stark et al. (1992, Cat. J/ApJS/79/77),
     Burstein & Heiles (1982, Cat. J/AJ/87/1165), and
     Lockman & Dickey (1995, ADIL FL 01L).
Note (3): Where RL=log[S(5GHz)]/log[S(1450Å)].



Byte-by-byte Description of file: refs.dat

   Bytes Format Units   Label     Explanations

   1-  2  A2    ---     Ref       Reference code
   4- 22  A19   ---     BibCode   BibCode
  24- 53  A30   ---     Aut       Author's name
  54- 78  A25   ---     Com       Comments


History:
    From electronic version of the journal
  * 03-Dec-2002: Added the figure number in table1.

References:
    Scott et al.,     Paper I         2000ApJS..130...37S
    Scott et al.,     Paper II        2000ApJS..130...67S
    Bechtlod et al.,  Paper III       2002ApJS..140..143B, Cat. J/ApJS/140/143
    Dobrzycki et al., Paper IV        2002ApJ...571..654D
(End)                    Greg Schwarz [AAS], Patricia Bauer [CDS]    13-Sep-2002