ADC/CDS Standard Document for Catalog:/journal_tables/A+AS/117/519/
ADC/CDS Standard Document for Catalog:| 1. Use the ADC Data Viewer Suite to visualize the data. |
|
| 2. Get the data files via anonymous FTP. (See Note.) |
|
J/A+AS/117/519 Structures around the SGP (Escalera+, 1996)
================================================================================
Detection of structures on multiple scales around the South Galactic Pole.
A two-dimensional analysis of the COSMOS/UKST Southern Sky Galaxy Catalogue.
Escalera E., MacGillivray H.T.
<Astron. Astrophys. Suppl. Ser. 117, 519 (1996)>
=1996A&AS..117..519E (SIMBAD/NED BibCode)
================================================================================
ADC_Keywords: Clusters, galaxy ; Morphology ; Photometry
Keywords: cosmology: large-scale structure of Universe -
galaxies: clusters - surveys - methods: data analysis
Description:
We report the results of a 2D analysis of distributions of galaxies in
a search for structures on a wide range of scales, from clusters up to
superclusters and beyond, including the identification of voids. The
structures are identified in data from the COSMOS/UKST Southern Sky
Galaxy Catalogue (CUSSGC). The subsample used in this first
investigation contains some 1.4x10^6^ galaxies in an area of
~69x44degrees around the South Galactic Pole. From our analysis, we
find 25 very large-scale structures (of 10 degrees or more in extent),
about 60 structures of intermediate scales (superclusters and/or
elongated features), and more than 220 cluster-sized objects. All
these features are significant, having high confidence levels for
detection. Some extended voids are also detected in this area,
likewise with high significance. This work is based on the use of the
wavelet transform, the method of which has already been extensively
described in a previous paper in which we demonstrated the principle
of the technique. The wavelet analysis gives the position of the
structures detected, together with significance levels and some
parametrisation of their properties (extent, population, elongation,
etc). Ultimately, our aim is the construction of a large and
homogeneous database of structures on all scales in this important
part of the southern sky.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1 45 12 Definition of the subsamples ("domains")
successively used for the detection.
table2 76 111 *Detection of the structures
table3 49 50 Membership of the structures detected
table4 57 96 Morphological topology of the structures
through the foreground set
table5 61 111 Summary of the large-scales detection results
for all the domains
table6 75 54 Definition of the subsamples ("volumes")
successively used for the small-scales detection
table7 79 234 Detection of the structures
table8 67 234 Membership of the structures detected.
table9 50 235 Morphological topology of the structures
table10 69 234 Summary of the small- and intermediate-scales
detection results for all the volumes.
table12 80 345 Multi-scale detection, the main database
table13 37 184 Identification with the ACO catalogue
--------------------------------------------------------------------------------
Note on table2: Results are listed for the 12 domains separately,
in consistency with the figures 1-12.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table1
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
5- 8 A4 --- No Codes that will be used through this paper.
13- 16 I4 --- Ngal Number of galaxies involved in the domains.
26- 30 F5.2 mag BjLow Lower limit of the B_j magnitude. (1)
34- 38 F5.2 mag BjUp Upper limit of the B_j magnitude. (1)
42- 45 F4.2 --- fi ? Parameter to take into account a distance
effect (see text) : fi is the rate in
dimensions from one field to another
(computation starts from [D180]).
--------------------------------------------------------------------------------
Note (1): Note that the first 3 subsamples are consecutive (the sum
involves all the available data), while the remaining 9 are
thinner and thinner magnitude slices.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 5 A4 --- No Identifies the sample to which the structure
belongs.
9- 14 F6.2 deg RAdeg [-36.40-22.50] Right ascension J2000 of the
structures following our procedure
i.e. the position of the central maximum of
the wavelet coefficients (see text).
18- 23 F6.2 deg DEdeg Declination J2000 of the structure
(decimal degrees)
27- 31 F5.3 --- PSL Significance level of the structures (1)
35- 38 A4 --- Name Labels of the structures
40- 45 F6.2 deg RAdeg2 [-37.28-22.57] Right ascension J2000 of the
centroid (2)
49- 54 F6.2 deg DEdeg2 Declination J2000 of the centroid (2)
58- 61 F4.2 deg m-axis Minor semi-axis
64- 68 F5.2 deg M-axis Major semi-axis
72- 76 F5.1 deg Theta Declination axis, increases toward the left
of the image (figures)
--------------------------------------------------------------------------------
Note (1): PSL gives the relative number of structures equivalent
found in a set of 1000 random simulations (see text), so value
s close to 0 identify high confidence levels.
Note (2): Parametrisation of the structures by ellipses.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
3- 6 A4 --- No Sample (domain) to which the structure belong
11- 13 I3 --- N1 Populations inside a circular areas centered
on the structures with a radius of 1 a_opt
18- 21 I4 --- N2 Populations inside a circular areas centered
on the structures with a radius of 5 a_opt.
Since wavelets are not sensitive to what
happens beyond 5 a_opt, Hence N2 can be
considered as the local background of the
structure.
26- 28 I3 --- E1 Excess of population (E1) inside the a_opt
area. (1)
33- 37 F5.2 --- Dn Delta_n parameter
41- 45 A5 --- Name Labels of the structures as previous tables
47- 49 F3.0 --- Nb Rank number within the domain.
--------------------------------------------------------------------------------
Note (1): The values of E1 are estimated in terms of local
fluctuations with the delta_n parameter given in the column Dn.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Zone [A-C] Zone considered (1)
4- 7 A4 --- Name Labels of the successive structures.
9- 24 A16 --- No Fields into which the structures appear;
the "+" symbol indicates that the concerned
structures also appear in an alternative set
26- 28 A3 --- Class Class to which the structure belongs, in terms
of extension (codes into brackets). (2)
34- 54 A21 --- Morph Morphological events within the respective
structures (3)
--------------------------------------------------------------------------------
Note (1): A: domains [D085], [D164], and [D169]
B: domains [D180], [D185], [D190], [D193], and [D196]
C: domains [D200], [D201], [D203], and [D205]
Note (2): The successive categories are as follows :
{W} = Oversized structures,
{V} = Very large structures,
{S} = Superclusters,
{E} = Intermediate or Elongated structures
{C} = Cluster-sized structures,
Note (3): The morphological events are defined in the form of a
series of keywords "includes" and "included in" identifies
structures fully overlapping each other;
"involves" and "involved in" identifies partial overlapping
"close to" denotes structures with the respective centroids
separated by less than the greater major axis but without any
superposition. Obviously optical superpositions are not taken into
account.
"isolated" identifies structures fully independent of each others.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
3- 8 F6.2 deg RAdeg [-37.28-22.57] Right ascension J2000 of the
centroid of the ellipse
12- 17 F6.2 deg DEdeg Declination J2000 of the centroid of the
ellipse
21- 25 F5.2 deg M-axis Major axis of the ellipse
30- 33 A4 --- Name Label of the structures. Symbol "=" denotes
structures identifyed in several domains
37- 40 A4 --- No Domain of appearance of the structures
45- 48 F4.2 --- fi []? Distance effect (see table 1)
53- 55 A3 --- Class Morphological classification (see table 4)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 5 A4 --- No Codes that will be used through this paper.
10- 14 I5 --- Ngal Number of galaxies involved in the successive
samples
18- 23 F6.2 deg RAdegLow Lower value of right ascension J2000 (1)
26- 31 F6.2 deg RAdegUp Upper value of right ascension J2000 (1)
38- 43 F6.2 deg DEdegLow Lower value of declination J2000 (1)
46- 51 F6.2 deg DEdegUp Upper value of declination J2000 (1)
56- 60 F5.2 mag BjLow Lower value of Bj magnitude (2)
64- 68 F5.2 mag BjUp Upper value of Bj magnitude (2)
70- 75 A6 --- n_Bjmag Part of Bj magnitude
--------------------------------------------------------------------------------
Note (1): Dimensions differ from one field to another, though
Note (2): Note that 3 volumes are splitted each into two parts (cuts in
magnitudes).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Zone Zone considered (1)
3- 6 A4 --- No Sample to which the structure belongs.
9- 14 F6.2 deg RAdeg [-39.99-25.54] Right ascension J2000 of the
central maximum of the wavelet coefficients
17- 22 F6.2 deg DEdeg Declination J2000 of the central maximum of
the wavelet coefficients
25- 29 F5.3 --- PSL Significance level of the structures (2)
32- 36 A5 --- Name Labels of the structures
39- 41 F3.0 --- Nb Rank numbers consistent with the marks on the
respective figures
43- 48 F6.2 deg RAdeg2 [-40.33-25.42] Right ascension J2000 of the
centroid
51- 56 F6.2 deg DEdeg2 Declination J2000 of the centroid
59- 63 F5.3 deg m-axis Minor axis of the ellipse
66- 70 F5.3 deg M-axis Major axis of the ellipse
73- 77 F5.1 deg Theta Orientation of the ellipse, referred to the
declination axis and increases toward the
left of the image (figures).
--------------------------------------------------------------------------------
Note (1): Results are listed for the 11 zones separately in consistency
with the figures 13-23.
Note (2): P_SL gives the relative number of structures equivalent
found in a set of 1000 random simulations (see text), so values
close to 0 identify high confidence levels.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table8
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Zone Zone considered
3- 6 A4 --- No Sample (volume) to which the structure belongs
11- 14 I4 --- N1 Populations inside a circular area centered
on the structures with a radius of 1 a_opt
19- 23 I5 --- N2 Populations inside a circular areas centered
on the structures with a radius of 5 a_opt.
Since wavelets are not sensitive to what
happens beyond 5 a_{opt}, N2 can be
considered as the local background of the
structure.
29- 31 I3 --- E1 ? Excess of population inside the a_{opt} area.
Then the values of E1 are estimated in terms
of local fluctuations with the delta_n
parameter
36- 40 F5.2 --- Dn ? Delta_n parameter
46- 50 A5 --- Name Label of the structures
56- 58 F3.0 --- Nb Rank number consistent with the marks on the
corresponding figures.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table9
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
3- 7 A5 --- Name Label of the structures.
12- 15 A4 --- No Volumes into which the structures appear.
23- 25 A3 --- Class Class to which the structure belong, in terms
of extension (codes into brackets, see also
table 4). (1)
30- 50 A21 --- Morph Morphological events within the respective
structures (2)
--------------------------------------------------------------------------------
Note (1): The only two categories concerned here are :
{C} = Cluster-sized structures,
{A} = Compact clusters or Associations.
Note (2): Morphological events are in the form of a series of key-words:
"includes" and "included in" identify structures fully overlapping
each other
"involves" and "involved in" identify partial overlapping
"close to" denotes structures with the respective centroids separated
by less than the greater major axis but without any superposition.
Obviously optical superpositions are not taken into account. The
absence of any comment identifies structures fully isolated.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table10
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
6- 11 F6.2 deg RAdeg [-40.33-25.42] Right ascension J2000 of the
ellipse centroid
19- 24 F6.2 deg DEdeg Declination J2000 of the ellipse centroid
32- 35 F4.2 deg M-axis Major axis
41- 45 A5 --- Name Label of the structure
50- 53 A4 --- Volume Volume of appearance of the structures
60 I1 --- IM []? Estimator of the distance effect scales
from 1 to 6
66- 68 A3 --- Class Morphological classification
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table12
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Samp [ABC] Sample A: Very Large Structures
B: Superclusters
C: Cluster-sized Structures
3- 10 A8 --- COS Numerotation of our own : "COS" refers to the
information that follows, i.e. coordinates
and sizes. The Very Large Structures are
numbered from 1, the Superclusters are
numbered from 100, and the lower scaled
structures are numbered from 1000.
15- 16 I2 h RAh Right ascension J2000
18- 21 F4.1 min RAm Right ascension J2000
28 A1 --- DE- Declination sign
29- 30 I2 deg DEd Declination J2000
32- 33 I2 arcmin DEm Declination J2000
39- 43 F5.2 deg M-axis Major axis of the ellipses that fits the
structures
49- 53 A5 --- Name Labels used through this paper, consistent
with all previous tables, figures and text.
58- 61 A4 --- Sample Subsample into which the successive structures
are detected :
"D" corres. to the magnitude slices (sect.4)
"V" to the volumes (section 5.).
68 I1 --- IM []? Index that informs on the magnitude
range of the concerned subsample : the
distance effect is supposed to increase with
values of IM.
73- 75 A3 --- Class Categories of the structures, in terms of
overall extension (codes into brackets). (1)
--------------------------------------------------------------------------------
Note (1): The successive categories are as follows :
{W} = Oversized structures,
{V} = Very large structures,
{S} = Superclusters,
{E} = Intermediate or Elongated structures,
{C} = Cluster-sized structures,
{A} = Compact clusters or Associations.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table13
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 F5.3 --- PSL Confidence level (1)
7- 10 F4.2 deg R Difference in the positions between our
structures (e.g. as listed in tables 2.)
and the Abell clusters
12- 19 A8 --- Abell Successive Abell clusters most likely
identified to our structures.
21- 23 I3 --- Ngal Population
25- 30 F6.4 --- z ? Redshift
32- 36 F5.2 mag Mag Magnitude of the 10th ranked galaxy, so we can
easily check the consistency with the
identifyed structure
--------------------------------------------------------------------------------
Note (1): Values greater than 0.050 correspond to structures not
significant from our procedure, thus not listed in the previous tables.
--------------------------------------------------------------------------------
Table 11. : Detection of the voids.
-----------------------------------------------------------------------------
approximative domains of magnitude
Void alpha delta extension P_SL appearance range (B_j)
------------------------------------------------------------------------------
OB -11.5 -20.0 27.0 x 10.0 0.000 D085, D164, D169 8.5 to 17.3
OC -11.0 -51.6 16.0 x 9.0 0.000 D085, D164, D169 8.5 to 17.3
OA +8.0 -38.0 9.0 x 6.0 0.027 D085 8.5 to 16.4
------------------------------------------------------------------------------
Courtesy: E. Escalera, <escalera@OBMARA.CNRS-MRS.FR>
References:
Escalera E., Mazure, A., 1992, ApJ, 388, 23 =1992ApJ...388...23E
Escalera E., MacGillivray H. T., 1995, A&A, 298, 1 =1995A&A...298....1E
MacGillivray H.T., Yentis D.J., 1994, in {Astronomy from Wide-Field
Imaging}, IAU Symposium No. 161, eds. H.T. MacGillivray et al.,
Kluwer Academic Publishers, Dordrecht, p. 632.
================================================================================
(End) Patricia Bauer [CDS] 28-Feb-1996