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1996ApJ...470..172Shectman+

VII/203 Las Campanas Redshift Survey (Shectman+ 1996)


The Las Campanas Redshift Survey

Shectman S.A., Landy S.D., Oemler A., Tucker D.L., Lin H., Kirshner R.P., Schechter P.L.

=1996ApJ...470..172S


ADC_Keywords: Redshifts ; Galaxy catalogs ; QSOs

Keywords: cosmology: observations - galaxies: clusters: general - galaxies: distances and redshifts - surveys

Abstract:

The Las Campanas Redshift Survey (LCRS) consists of 26,418 redshifts of galaxies selected from a CCD-based catalog obtained in the R band. The survey covers over 700deg^2 in six strips, each 1.5x80deg, three each in the north and south Galactic caps. The median redshift in the survey is about 30,000km/s. Essential features of the galaxy selection and redshift measurement methods are described and tabulated here. These details are important for subsequent analysis of the LCRS data. Two-dimensional representations of the redshift distributions reveal many repetitions of voids, on the scale of about 5000km/s, sharply bounded by large walls of galaxies as seen in nearby surveys. Statistical investigations of the mean galaxy properties and of clustering on the large scale are reported elsewhere. These include studies of the luminosity function, power spectrum in two and three dimensions, correlation function, pairwise velocity distribution, identification of large-scale structures, and a group catalog.

Description:

In referencing individual galaxies within the LCRS, it is recommended that investigators adhere to the IAU-registered LCRS naming convention, as listed in the online "dictionary of nomenclature of celestial objects" (http://astro.u-strasbg.fr/cgi-bin/Dic), which is: LCRS BHHMMSS.s-DDMMSS, in which the coordinates are equinox 1950.0, RA is truncated (* not rounded *) to a tenth of a second, and DEC is truncated (* not rounded *) to a whole arcsecond.

See also: See also the LCRS home pages at: http://manaslu.astro.utoronto.ca/~lin/lcrs.html http://www.aip.de:8080/~tucker/lcrs-mirror.html

File Summary:
--------------------------------------------------------------------------------
  FileName      Lrecl  Records   Explanations
--------------------------------------------------------------------------------
ReadMe             80        .   This file
fields            122      289   LCRS spectroscopic fields  (Table 2)
catalog            98    82360   Redshift catalog (Table 3)
--------------------------------------------------------------------------------

Byte-by-byte Description of file: fields
--------------------------------------------------------------------------------
   Bytes Format Units   Label     Explanations
--------------------------------------------------------------------------------
   1-  8  A8    ---     Field     Field designation (1)
  10- 11  I2    h       RA1h      First boundary field right ascension (1950.0)
  13- 14  I2    min     RA1m      First boundary field right ascension (1950.0)
  16- 20  F5.2  s       RA1s      First boundary field right ascension (1950.0)
  22- 23  I2    h       RA2h      Second boundary field right ascension (1950.0)
  25- 26  I2    min     RA2m      Second boundary field right ascension (1950.0)
  28- 32  F5.2  s       RA2s      Second boundary field right ascension (1950.0)
      34  A1    ---     DE1-      First boundary field declination sign
  35- 36  I2    deg     DE1d      First boundary field declination (1950.0)
  38- 39  I2    arcmin  DE1m      First boundary field declination (1950.0)
  41- 44  F4.1  arcsec  DE1s      First boundary field declination (1950.0)
      46  A1    ---     DE2-      Second boundary field declination sign
  47- 48  I2    deg     DE2d      Second boundary field declination (1950.0)
  50- 51  I2    arcmin  DE2m      Second boundary field declination (1950.0)
  53- 56  F4.1  arcsec  DE2s      Second boundary field declination (1950.0)
  58- 62  F5.2  mag     m1        Lower limit magnitude (2)
  64- 68  F5.2  mag     m2        Higher limit magnitude (2)
  70- 74  F5.2  mag     mcen      Faint central magnitude limit at m2 (2)
  76- 78  I3    ---     Nfib      Designates whether data was obtained with
                                   the 50- or 112-object spectrograph system
  80- 82  I3    ---     Ngal      Number of galaxies, within the geometric and
                                   photometric limits of the field, which
                                   have redshifts.
  84- 87  F4.2  ---     f         Sampling fraction (3)
  89- 96  A8 "DD/MM/YY" Night     Spectroscopic observations date
  98-100  I3    ---     Frame     Spectroscopic exposure number
 102-121  A20   ---     plate     Spectroscopic plate designation
--------------------------------------------------------------------------------
Note (1):  "W", "E", or "M" means west, east, or middle,
Note (2): Photometric selection limits. Note the catalogs always contain
           objects outside the photometric limits.
           Isophotal magnitude m and central magnitude m_c_ of each galaxy
           must meet the photometric selection criteria m1 <= m < m2
            and m_c_ < m_cen_ - 0.5(m2-m)
Note (3): Fraction of objects (galaxies plus stars) with velocities, among
           those objects meeting the photometric selection limits.
--------------------------------------------------------------------------------

Byte-by-byte Description of file: catalog
--------------------------------------------------------------------------------
   Bytes Format Units   Label Explanations
--------------------------------------------------------------------------------
   1-  8  A8    ---     Field Field designation
  10- 15  F6.1  ---     p     Photometric catalog object number
  17- 21  F5.2  mag     mag   Isophotal magnitude
  23- 32  A10   ---     Scan  Designation of drift scan used to obtain object
                               photometry
  34- 38  F5.2  mag     mc    Central magnitude
  40- 41  I2    h       RAh   Right Ascension (1950.0)
  43- 44  I2    min     RAm   Right Ascension (1950.0)
  46- 50  F5.2  s       RAs   Right Ascension (may be 60.00) epoch 1950.0
      52  A1    ---     DE-   Declination sign
  53- 54  I2    deg     DEd   Declination (1950.0)
  56- 57  I2    arcmin  DEm   Declination (1950.0)
  59- 62  F4.1  arcsec  DEs   Declination (may be 60.0) epoch 1950.0
  64- 66  A3    ---     s     ? Spectroscopic fiber designation (1)
  68- 69  A2    ---     type  ? Spectrum type (1) (2)
  71- 75  I5    km/s    cz    ? Heliocentric velocity (1)
  77- 80  I4    km/s  e_cz    ? rms uncertainty on cz
  82- 86  F5.3  ---     sf    ? Product of sampling fraction, apparent magnitude
                                 completeness, and central surface brightness
                                 completeness factors (1) (3)
  88- 92  F5.3  ---     gsf   ? Same as sf but sampling fraction is computed
                                 only in a 1000"-radius neighborhood of the
                                 galaxy (1) (4)
  94- 98  I5    km/s    cz55  ? Instrumental constraints prevent two object
                                 fibers from approaching closer than 55"
                                 on the sky (1) (5)
--------------------------------------------------------------------------------
Note (1): Columns "s" to "cz55" are blank if not applicable to a particular
           object
Note (2): Spectrum type.
           - c, e, b: galaxy
                      - c: velocity from cross-correlation only
                      - e: velocity from emission-line fitting only
                      - b: velocity from both c and e
           - *: star
           - ?: spectrum failed to yield redshift
           - nh, tc, bl: same as no spectrum attempted 
                         (intended spectrum not observed)
           - QS: QSO
           - PN: planetary nebula
Note (3): See Lin et al. (1996ApJ...464...60L) for more information;
           sf = f * F * G in the notation of that paper.
           Objects should be weighted by 1/sf in statistical analyses.
           Only those galaxies meeting the photometric selection limits have
           an entry.
Note (4): This attempts to account for any variable geometric sampling effects,
           e.g. the reduced spectroscopic success at field corners
           (Shectman et al. 1995, in Wide-Field Spectroscopy and the Distant
             Universe, proceedings of the 35th Herstmonceux Conference
             (July 1994), eds. S. J. Maddox & A. Aragon-Salamanca
             (Singapore: World Scientific), p. 98.).
          Experience with the galaxy power spectrum (Lin et al.,
           1996ApJ...471..617L) shows that using gsf instead of sf makes little
           difference, but it does not hurt to check this for your own analyses.
Note (5): For an object without a redshift, cz55 is the velocity of its closest
           neighbor within 55", if one exists, that has a velocity. Only objects
           within the photometric limits have an entry. To assess the
           significance of this selection effect for your particular analysis,
           you can try assigning fake velocities as described in
           Lin et al. (1996ApJ...471..617L).
--------------------------------------------------------------------------------

Origin: AAS CD-ROM series, Volume 7, 1996           Lee Brotzman [ADS] 22-Oct-96
================================================================================
(End)                                         Patricia Bauer, [CDS]  03-Feb-1997