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FAIRALL91: southern redshifts catalogue

Contents

Table name: 	fairall
Records: 	12844
Version:        1991
Spectral Band: 	OPT,RADIO
Kind of Object: Galaxy,BlLac,Radio Sources,Seyfert
Mode: 		Redshift
PreView:
Coordinates: 	B1950

Reference

Description

This catalogue provides a "best-estimate" of the heliocentric radial velocities of some 13000 galaxies south of Declination 0 degrees. It is based on over 17000 redshift measurements, from over 200 sources, either published or otherwise made public. Aside from redshift references, each entry includes flags as to whether the velocity is from optical or radio observations, or both, as well as an indication of the nature of any optical emission lines. Galaxies with velocities beyond 75000 km/s are not included. All entries have been made interactivly, by one person (A.P.F.). The interaction was necessary because different investigators may use different names, quote slightly different positions, and obtain slightly different velocities for the same galaxy. Thus duplicate entries for the same galaxy are avoided (although a few may inevitably be included).

Fields


Name		Meaning

name		Object Name
ra_ori		R.A. B1950
dec_ori		Declination B1950
lii_ori		Galactic Longitude (precision: tenth of degree)
bii_ori		Galactic Latitude  (precision: tenth of degree)
z		Redshift
ref1		Reference (see catalogue Fairall91_ref) 
ref2
ref3
ref4
ref5
ref6
ref7
type		Kind of object:

	S1		Seyfert 1
	S2 		Seyfert 2
	S3 or S?	Suspected Seyfert 
	BL		BL Lac object
	H2		H II emission, generally implying strong emission 
			lines of relatively high excitation, including 
			[O III] 5007 + 4959 emission
	EM		Generally implies low-excitation 
			emission, [O II] 3727 and/or H-alpha,
			or unspecified emission

band_flag	The reference or references only give optical velocities

	R - The reference or references only give radio velocities
	B - Both optical and radio velocities

ra		Right Ascension J 2000
dec		Declination J 2000
lii		Galactic Longitude (full precision)
_bii		Galactic Latitude (full precision)

General remarks

This catalogue was first published in 1981. The present work is an update and extension of the 4th version, completed in January 1988. Since that version, the northern Declination limit has been shifted from -17.5 degrees to the equator, and radio velocities have been included. The new version, including updated references, has just over double the number of galaxies in the previous version. While most of the references are original source papers, the catalogue was founded on the de Vaucouleurs Second Reference Catalogue (Ref 001) to take care of references prior to 1975. In similar fashion, the HI database of Bottinelli et al (Ref 150), published in 1990, has been used to fill in many of the radio velocities. Literature searches have been made covering the main journals up to Apr-Jun 1991. Whilst the aim is to obtain all available redshifts, experience has shown that, inevitably, some references are overlooked, and no claim to completeness can be made. This is particularly applicable to the Declination zone 0 to -17.5 degrees, into which the catalogue has recently been extended. Apologies are made to any author whose work has been unintentionally omitted. We would obviously welcome any reports regarding reference coverage.

The preparation of a definitive catalogue that includes all sources, with exhaustive searching and detailed checking, is a major task. Its coverage must necessarilly lag behind current literature. The present work does not claim to be a definitive work, but its coverage is up to only 3 or 4 months short of its publication.

Past versions of this catalogue have been well received, and demand has prompted the preparation of the new version. One of us (A.P.F.) is also involved in the preparation of the definitive updated version of the "Catalogue of Radial Velocities of Galaxies" with G.G.C. Palumbo, G. Vettolani and G. Baiesi-Pillastrini, based in Bologna. That catalogue shows all individual measurements for galaxies over the whole sky. A significant fraction of the effort to produce a catalogue of this nature goes to dealing with references that give only designations (not always obvious ones) of galaxies without providing their coordinates - or which give only galactocentric, not heliocentric, velocities. Such references can take a considerable amount of processing, even before they are entered. Authors and referees should appreciate the importance of accurate coordinates (even with obvious NGC galaxies) for identification purposes. The released version of this catalogue is a public version. The full catalogue does include a few hundred addition redshifts (obtained at the South African Astronomical Observatory, in collaboration with L. da Costa and his group) that have not yet been published.

Computer management

The catalogue is managed in IBM-compatible PCs using dedicated software developed by one of us (A.J.). It allows almost instant access to galaxies at any coordinate position, or within a chosen error box. It offers full editing facilties and can produce ASCII files etc. The procedure for entering a new velocity determination is initiated by typing in (or interactively feeding from a file) the 1950 coordinates. The computer then searches within 1m in R.A. and 2 arcmin in Declination (the generous range in R.A. is to allow for objects close to the pole), so to determine if an entry for the galaxy already exists. The option is then given to decide whether to add a new entry or edit an existing one. One of the features of the software package is the identification of any form of subset of the data - such as all galaxies within a specified range of R.A. and Declination, range of galactic longitude and latitude, specified velocity range or common velocity flag, common reference or common type. Obviously such subsets are not available in this publication, but special requests can be considered.

Designation

The designations have been entirely picked up from the references quoted. Thus, if references choose to ignore recognised designations (such as NGC or ESO) they may also be absent in the catalogue. In general, ESO designations have been contracted to an "E" prefix. When multiple designations cause space problems, further contractions, such as NGC to an "N' prefix, are made. Further information to that given below is included, where appropriate, in the reference lists.

Coordinates

1950 Coordinates and galactic longitude and latitude are given. In earlier versions of the catalogue, declinations were rounded off to the nearest 15 arcsec - this remains for many entries under references 001 to 078. Some entries from Ref 131 onwards were entered from files (put in the same format as the Bologna catalogue); these have declinations rounded off to the nearest 6 arcsec. Where galaxies are reported by different observers, small differences in coordinates sometimes occur, but usually these are less than 3s in R.A. and 30 arecsec in Declination. In general, many observers make use of the Lauberts catalogue so positions are coincidental in the stated coordinates.

Heliocentric Vel. (cz)

This column provides the "best estimate" of the Heliocentric velocity. If only a single reference is available, then the value quoted is straight from that reference. Although individual errors are not shown, a general error for the reference concerned may be shown in the reference list. We have tried to provide estimated EXTERNAL errors for the refences. Where these are not shown, one can assume the standard deviation of the external error to be in the region 100-120 km/s. As a general rule, the true external errors are twice that claimed by the authors! Experience has shown that, in general, about one or two percent of the redshift velocities from a given source are completely erroneous (and sometimes the percentage is higher). This is apparently unavoidable, given the nature of optical galaxy spectra or radio confusion, and even the most careful investigators are sometimes fooled by spurious features or detections. Similarly, cross correlations on optical spectra can sometimes latch on to the wrong values. Since the bulk of this catalogue concerns single reference redshifts, it is possible that 1 percent or so are erroneous. When two or more redshift references are shown for a galaxy, the catalogue velocity is a form of mean value, rounded off to the nearest 10 km/s (except if the velocities agreed to within 20 km/s, when it is rounded to 1 km/s). In deciding this mean value, extra weighting was given to certain references known to be more accurate. In general, those optical velocities from higher dispersion spectra (with external errors better than 50 km/s) had triple weight. Radio redshifts were given still higher weight, but only when supported by optical observations. If the reference numbers for an individual galaxy are not sequential (eg 132 076), then the mean value is weighed towards the value in the first reference (ie 132). The maximum acceptable differences between optical velocities is considered here to be 400 km/s, that between radio velocities is 100 km/s. If only two references are available, and there is no indication as to which is likely to be correct, then, rather than enter an uncertain value, a flag "LD" (for Large Difference) is substituted when the difference is greater than the above. Where there are three or more references, but one is discrepant (the others are considered valid), the discrepant reference is separated from the others by a blank space (e.g. 079 082 076). There are, in the catalogue, a few cases where three references fail to show any agreement, and one case where four different references all show totally different redshifts for the same galaxy. A few authors quote only galactocentric, rather than heliocentric, velocities, ie Vo (= V + 300 sin l cos b); where possible, we have calculated cz = V, but usually rounded off to 10 km s-1. There are other cases where flags occur in place of a velocity. These are:

Reference Fields

The source references are given a three-digit numerical code. As mentioned above, the catalogue was originally founded on data extracted from the de Vaucouleurs Second Reference Catalogue (Reference 001 - which covers redshift measurements published 1975 and earlier) with subsequent additions (References 002 onwards). Thus the listing that follows forms a source of southern redshifts, except that a number of Seyfert galaxies, having a single reference for a single galaxy, have been put under umbrella Seyfert lists. The numerical codes for references simply reflect the order in which the data were entered into the catalogue. It is roughly chronological (but occasionally a reference overlooked earlier is added). Gaps in sequential reference numbers result from some consolidation of references used in earlier editions. or where references are not yet public. When multiple references are listed, the order may reflect the weighting given to velocities (see above).

Type

The second last column identifies Seyfert galaxies, and partially identifies other galaxies with emission lines in their optical spectra (where this can be easily read from the reference concerned).

Abbreviations are as follows: 

	S1		Seyfert 1
	S2		Seyfert 2
	S3 or S?	Suspected Seyfert
	BL		BL Lac object
	H2		H II emission, generally implying strong 
			emission lines of relatively high excitation, 
			including [O III] 5007 + 4959 emission.  
	EM		Generally implies low-excitation emission, [O II] 3727 
			and/or H-alpha, or unspecified emission.

These classifications are obviously not uniform between different references, but nevertheless serve as a useful indication.

Band Flag

The flag is as follows:

Older references

1981 Catalogue "A Simple Source Catalogue of Galaxies south of Declination -17.5 degrees that have been observed spectroscopically" P.J.K. Dobbie and A.P. Fairall, Publ. Dept. Astr. Univ. Cape Town, No. 4.

1983 Catalogue "A Catalogue of Galaxies south of Declination -30 degrees that have been observed spectroscopically" A.P. Fairall, L. Lowe and P.J.K. Dobbie, Publ. Dept. Astr. Univ. Cape Town, No. 5.

1983 Plots "The Spatial Distribution of Galaxies in the Southern Sky" H. Winkler, Mon. Not. Astr. Soc. Sthn. Africa, 42, 74. "The Spatial Distribution of Galaxies in the Southern Sky" A.P. Fairall and H. Winkler in "Clusters and Groups of Galaxies", p. 23. F. Mardirossian et al. (Eds.) Reidel, 1984.

1984 Plots "A Southern Redshift Survey - Redshift-Space Distributions of Normal and Active Galaxies South of Declination -30 degrees" A.P. Fairall, Publ. Dept. Astr. Univ. Cape Town, No. 6.

1985 Catalogue "A Catalogue of Galaxies South of Declination -30 degrees that have been observed spectroscopically (1985 Version)" A.P. Fairall, Publ. Dept. Astr. Univ. Cape Town, No. 7. Machine-Readable Version by Anne C. Raugh (March 1987) distributed by the Astronomical Data Center, NASA Goddard Space Flight Center.

1988 Catalogue and Plots "Southern Redshifts - Catalogue and plots" A.P. Fairall and A. Jones, Publ. Dept. Astr. Univ. Cape Town, No. 10. Machine-Readable Version by Anne C. Raugh (January 1989) distributed by the Astronomical Data Center, NASA Goddard Space Flight Center.

1990 Plots "Large-Scale Structure in the Universe: Plots from the Updated Catalogue of Radial Velocities of Galaxies and the Southern Redshift Catalogue" A.P. Fairall, G.G.C. Palumbo, G. Vettolani, G. Kauffmann, A. Jones and G. Baiesi-Pillastrini, Mon. Not. R. astr. Soc., 247, 21P.

Errata

The three errors mentioned as "Corrections to October 1991 Version as noted November 1, 1991" were reported, namely: