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J/AJ/136/181        Spectroscopy of PC 1643+4631A,B          (Casey+, 2008)
PC 1643+4631A,B: the Lyman-α forest at the edge of coherence.
    Casey C.M., Impey C.D., Petry C.E., Marble A.R., Dave R.
   <Astron. J., 136, 181-196 (2008)>
   =2008AJ....136..181C
ADC_Keywords: QSOs ; Spectroscopy ;  Equivalent widths ; Redshifts

Keywords: cosmology: observations - intergalactic medium -
          quasars: absorption lines - quasars: individual (PC 1643+4631A, B)

Abstract:
    This is the first measurement and detection of coherence in the
    intergalactic medium (IGM) at substantially high redshift (z∼3.8) 
    and on large physical scales (∼2.5h-170Mpc). We perform the
    measurement by presenting new observations of the high-redshift quasar
    pair PC 1643+4631A, B and their Lyα-absorber coincidences. With
    data collected from Keck I Low Resolution Imaging Spectrometer (LRIS)
    in a 10200s integration, we have full coverage of the Lyα
    forest over the redshift range 2.6<z<3.8 at a resolution of 3.6Å
    (∼220km/s).

Description:
    All data for this project were obtained with the Keck I Low Resolution
    Imaging Spectrometer (LRIS) on 2001 July 21 and were reduced using the
    standard IRAF longslit-spectra pipeline. To cover the wavelength range
    of scientific interest, only the red side of the spectrograph and the
    900/5500 grating was used.
Objects:
    -------------------------------------------------------
       RA   (2000)   DE      Designation(s)
    -------------------------------------------------------
    16 45 00.7   +46 26 13   PC 1643+4631A = QSO B1643+465A
    16 45 19.6   +46 25 38   PC 1643+4631B = QSO B1643+465B
    -------------------------------------------------------

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table1.dat        28     4104   Flux and continuum of PC 1643+4631 A,B
table2.dat        68      240   Absorption lines for PC 1643+4631A
table3.dat        68      234   Absorption lines for PC 1643+4631B
table4.dat        45      152   Symmetrically matched Lyα lines


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

   Bytes Format Units         Label     Explanations

       1  A1    ---           Comp      [AB] Component of PC1643+4631
   3-  8  F6.1  0.1nm         lambda    Wavelength in Angstroms (Å)
  10- 15  F6.3  10-19W/m2/nm  Flux      Flux density (1)
  17- 21  F5.3  10-19W/m2/nm  e_Flux    Error in Flux (1)
  23- 28  F6.3  10-19W/m2/nm  CFlux     Continuum flux density (1)

Note (1): In units of 10-17ergs/s/cm2/Å.



Byte-by-byte Description of file: table[23].dat

   Bytes Format Units   Label     Explanations

   1-  3  I3    ---     Line      Line identification number
   5- 11  F7.2  0.1nm   lambda    Central wavelength in Angstroms (Å)
  13- 16  F4.2  0.1nm   e_lambda  Uncertainty in lambda in Angstroms (Å)
  18- 21  F4.2  0.1nm   Wobs      Equivalent width in Angstroms (Å)
  23- 26  F4.2  0.1nm   e_Wobs    Uncertainty in Wobs in Angstroms (Å)
  28- 32  F5.2  ---     chi       Reduced χ^2^ value (1)
  34- 38  F5.2  ---     Sfit      Equivalent width significance (2)
  40- 45  F6.2  ---     Sdet      Detection limit significance (3)
  47- 52  F6.4  ---     z         ? Redshift of absorber
  54- 56  A3    ---     f_z       [a-f ,] Flag on line (4)
  58- 68  A11   ---     n_z       Notes on line

Note (1): If this value is identical to that of an adjacent line, it
     indicates that the lines were fitted simultaneously.
Note (2): Defined as Wobs/σfit, where σfit is the error in
     the equivalent width.
Note (3): Defined as Wobs/σdet, where σdet is the detection
     limit of the data at λ (see text for further details).
Note (4): Flags as follows:
      a = line included in the Lyα sample
      b = line associated with the opaque system at z=3.777 that is also
          labeled by its associated identification
      c = line redward of Lyα emission which is clearly excluded from
          the Lyα sample
      d = line fitted in the damped region at z=3.818
      e = line associated with the opaque system at z=3.818 that is also
          labeled by its associated identification
      f = the blended line removed due to low significance


Byte-by-byte Description of file: table4.dat

   Bytes Format Units   Label     Explanations

   1-  3  I3    ---     Match     Symmetrically matched pair number
   5- 11  F7.2  0.1nm   Alambda   Wavelength in spectrum A (in Å)
  13- 19  F7.2  0.1nm   Blambda   Wavelength in spectrum B (in Å)
  21- 24  F4.2  0.1nm   Dlambda   Wavelength separation of pair (in Å)
  26- 30  F5.1  km/s    dVel      Velocity difference of pair
  32- 35  F4.2  0.1nm   W0A       Rest equivalent width in spectrum A (in Å)
  37- 40  F4.2  0.1nm   W0B       Rest equivalent width in spectrum B (in Å)
  42- 45  F4.2  0.1nm   dW0       Difference in rest equivalent widths (in Å)


History:
    From electronic version of the journal
(End)                  Greg Schwarz [AAS], Patricia Vannier [CDS]    21-Jan-2011