J/A+A/478/701   Color excess of SDSS quasars with DLA systems  (Vladilo+, 2008)
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The color excess of quasars with intervening DLA systems.
Analysis of the SDSS data release five.
    Vladilo G., Prochaska J., Wolfe A.M.
   <Astron. Astrophys. 478, 701 (2008)>
   =2008A&A...478..701V
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ADC_Keywords: QSOs ; Redshifts ; Photometry
Keywords: ISM: dust, extinction - galaxies: ISM - galaxies: high-redshift -
          quasars: absorption lines

Abstract:
    We analyzed the spectroscopic and photometric database of the 5th data
    release of the Sloan Digital Sky Survey (SDSS) to search for evidence
    of the quasar reddening produced by dust embedded in intervening
    damped Ly{alpha} (DLA) systems. From a list of 5164 quasars in the
    interval of emission redshift 2.25<=z_e_<=3.5 and SDSS spectra with
    signal-to-noise ratio SNR>~4, we built up an "absorption sample" of
    248 QSOs with a single DLA system in the interval of absorption
    redshift 2.2<z_a_<=3.5 and a "pool" of 1959 control QSOs without DLA
    systems or strong metal systems. For each QSO of the absorption sample
    we extracted from the pool a subset of control QSOs that are closest
    in redshift and magnitude.

File Summary:
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 FileName   Lrecl  Records   Explanations
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ReadMe         80        .   This file
table1.dat    104      248   The DLA absorption sample of quasars
table2.dat     38     1959   The pool of control quasars
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See also:
   http://www.sdss.org/ : The SDSS Home Page
   J/MNRAS/354/L31 : SDSS DR2 QSO and DLA properties (Murphy+, 2004)

Byte-by-byte Description of file: table1.dat
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   Bytes Format Units  Label    Explanations
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   1- 19  A19   ---    SDSS     SDSS identifier of the DLA quasar
                                (JHHMMSS.ss+DDMMSS.s)
  21- 24  F4.2  ---    zem      Emission redshift of the quasar
  26- 30  F5.2  mag    rmag     SDSS r magnitude
  32- 36  F5.3  ---    zabs     Absorption redshift
  38- 42  F5.2  cm-2   logN(HI) HI column density of the DLA system
  44- 47  F4.2  ---    d(zem)   bin in zem of the subset of control quasars (1)
  49- 52  F4.2  mag    d(rmag)  bin in rmag of the subset of control quasars (2)
  54- 59  F6.3  mag    <(r-z)0> Mean (r-z) color of the control sub-set (3)
  61- 65  F5.3  mag  e_<(r-z)0> Standard deviation of the mean <(r-z)_0>
  67- 72  F6.3  mag    <(g-z)0> Mean (g-z) color of the control sub-set (3)
  74- 78  F5.3  mag  e_<(g-z)0> Standard deviation of the mean <(g-z)_0>
  80- 85  F6.3  mag    D(r-z)   Deviation from mean (r-z) color index (4)
  87- 91  F5.3  mag  e_D(r-z)   Error of Delta(r-z)
  93- 98  F6.3  mag    D(g-z)   ?=- Deviation from mean (g-z) color index (4)
 100-104  F5.3  mag  e_D(g-z)   ? Error of Delta(g-z)
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Note (1): Width of the bin in emission redshift adopted for selecting the
          sub-set of control quasars
Note (2): Width of the bin in r magnitude adopted for selecting the sub-set
          of control quasars
Note (3): Mean color and dispersion of the sub-set of control quasars 
          selected at the same zem and rmag of the DLA-quasar
Note (4): Deviation from the mean color of the DLA-quasar
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Byte-by-byte Description of file: table2.dat
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   Bytes Format Units  Label Explanations
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   1- 18  A18   ---    SDSS  SDSS identifier of the control quasar
                              (HHMMSS.ss+DDMMSS.s, J2000)
  21- 24  F4.2  ---    zem   emission redshift of the control quasar
  27- 31  F5.2  mag    rmag  SDSS r magnitude of the control quasar
  37- 38  I2    ---    S/N   Mean signal-to-noise ratio of the SDSS spectrum (1)
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Note (1): Mean signal-to-noise ratio of the SDSS spectrum in the rest-frame
          spectral window 1440-1490{AA}.
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Acknowledgements:
    Giovanni Vladilo, vladilo@oats.inaf.it
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(End)                                        Patricia Vannier [CDS]  07-Jan-2008