README file for tables in tar file "lcrscat.tar". ----------------------------------------------- The Las Campanas Redshift Survey Catalog Format ----------------------------------------------- ===================================================================== BEFORE PROCEEDING, PLEASE FIRST REFER TO SHECTMAN ET AL. (1996) FOR A FULL DESCRIPTION OF THE SURVEY AND ASSOCIATED SELECTION EFFECTS. ===================================================================== For each of the 327 fields in the Las Campanas Redshift Survey (LCRS) proper, there is one ascii table which catalogs the photometric and spectroscopic information for that field. The tables are named "1003-12W.cat", etc., where "1003" denotes RA, "-12" denotes DEC, and "W", "E", or "M" means west, east, or middle, respectively. Note that the tables only contain those objects initially classified as galaxies on the basis of photometric information (though subsequent spectroscopy indicates that a small fraction are actually stars; see Shectman et al. 1996). Also, the tables have been edited down to the RA and DEC boundaries given in the table headers (see below). However, the tables have NOT been edited to the photometric limits (also below), so that the user needs to apply explicitly the photometric limits before generating samples for analysis. Also, to properly use the spectroscopic sample, the user needs to appropriately weight each galaxy by the quantity 1/sf as indicated below. These tables only include objects within the geometric boundaries of the LCRS "proper". Hence there are 25327 instead of the 26418 total galaxy redshifts quoted in Shectman et al. (1996); the excluded galaxies lie either in overlap areas among the original spectroscopic fields or in 5 additional fields outside the 6 main survey "slices". Moreover, note that the survey proper consists of 23697 galaxies, once BOTH the survey photometric selection criteria and the survey geometric boundaries are applied. Each table begins with a 9-line header containing the following information: Line 1: Field name. Lines 2-3: Epoch 1950.0 RA and DEC boundaries. Line 4: Photometric selection limits. Note the catalogs always contain objects outside the photometric limits. - Isophotal magnitude limits: m1 <= m < m2 - Central magnitude limits: mc < mcen - 0.5(m2-m) Line 5: Nfib: Designates whether data was obtained with the 50- or 112-object spectrograph system. Ngal: Number of galaxies, within the geometric and photometric limits of the field, which have redshifts. f: Sampling fraction = fraction of objects (galaxies plus stars) with velocities, among those objects meeting the photometric selection limits. Line 6: night: Date spectroscopic observations were obtained. frame: Spectroscopic exposure number. plate: Spectroscopic plate designation. Line 7: Blank. Lines 8-9: Column headings for rest of table. The body of the table then consists of the following columns: ------------------------------------------ Columns Format Units Label ------------------------------------------ 1- 9 A9 --- p# 11- 15 F5.2 mag m 18- 27 A10 --- scan 30- 34 F5.2 mag mc 39- 41 I3 h RAh 43- 44 I2 min RAm 46- 50 F5.2 sec RAs 52- 54 I3 deg DECd 56- 57 I2 arcmin DECm 59- 62 F4.1 arcsec DECs 65- 67 A3 --- s# 69- 70 A2 --- type 73- 77 I5 km/s cz 79- 82 I4 km/s err 85- 89 F5.3 --- sf 92- 96 F5.3 --- gsf 99-103 I5 km/s cz55 ------------------------------------------ p#: Photometric catalog object number. m: Isophotal magnitude. scan: Designation of drift scan used to obtain object photometry. mc: Central magnitude. RA: Right Ascension epoch 1950.0. DEC: Declination epoch 1950.0. (Note that the following columns will be blank if not applicable to a particular object.) s#: Spectroscopic fiber designation. type: 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 - QS: QSO - PN: planetary nebula cz: Heliocentric velocity in km/s. err: Velocity error in km/s. sf: Product of sampling fraction, apparent magnitude completeness, and central surface brightness completeness factors. See Lin et al. (1996a) 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. gsf: Same as sf but sampling fraction is computed only in a 1000"-radius neighborhood of the galaxy. This attempts to account for any variable geometric sampling effects, e.g. the reduced spectroscopic success at field corners (Shectman et al. 1995). Experience with the galaxy power spectrum (Lin et al. 1996b) shows that using gsf instead of sf makes little difference, but it does not hurt to check this for your own analyses. cz55: Instrumental constraints prevent two object fibers from approaching closer than 55" on the sky. 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. (1996b). ===================================================================== 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. ===================================================================== REFERENCES Lin, H., Kirshner, R. P., Shectman, S. A., Landy, S. D., Oemler, A., Tucker, D. L., & Schechter, P. L. 1996a, "The Luminosity Function of Galaxies in the Las Campanas Redshift Survey," ApJ, 464, 60. Lin, H., Kirshner, R. P., Shectman, S. A., Landy, S. D., Oemler, A., Tucker, D. L., & Schechter, P. L. 1996b, "The Power Spectrum of Galaxy Clustering in the Las Campanas Redshift Survey," ApJ, 471, in press. Shectman, S. A., Landy, S. D., Oemler, A., Tucker, D. L., Kirshner, R. P., Lin, H., & Schechter, P. L. 1995, "The Las Campanas Fiber-Optic Redshift Survey", 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. Shectman, S. A., Landy, S. D., Oemler, A., Tucker, D. L., Kirshner, R. P., Lin, H., & Schechter, P. L. 1996, "The Las Campanas Redshift Survey," ApJ, 470, 172 SEE ALSO THE LCRS HOME PAGES AT: http://manaslu.astro.utoronto.ca/~lin/lcrs.html http://www.aip.de:8080/~tucker/lcrs-mirror.html