J/ApJS/107/1 Morphologies of distant galaxies II (Abraham+ 1996)
The morphologies of distant galaxies.
II. Classifications from the Hubble space telescope medium deep survey.
Abraham R.G., van den Bergh S., Glazebrook K., Ellis R.S.,
Santiago B.X., Surma P., Griffiths R.E.
<Astrophys. J. Suppl. Ser. 107, 1 (1996)>
=1996ApJS..107....1A 1996ApJS..107....1A
ADC_Keywords: Morphology ; Galaxies, photometry
Mission_Name: HST
Keywords: galaxies: evolution - galaxies: fundamental parameters -
galaxies: interactions - surveys
Abstract:
The morphological properties of high-redshift galaxies are
investigated using a sample of 507 objects (I<22.0mag) from the
Hubble Space Telescope (HST) Medium Deep Survey. Independent visual
morphological classifications for each galaxy are used to quantify the
statistical uncertainties in the galaxy classifications. Visual
classifications are found to agree well for I<21mag. Fainter than
I=21mag significant disagreements are seen in the independent visual
classifications of late-type systems with T>7, merging systems, and
peculiar galaxies. The classifications of these systems are shown to
be somewhat subjective. Objective classifications based upon
measurements of central concentration and asymmetry for the Medium
Deep Survey sample are presented. These classifications are calibrated
using measurements of structural parameters for an artificially
redshifted sample of local objects. Morphologically segregated number
counts using both sets of visual classifications and objective
classifications support the conclusion that the observed galaxy counts
agree with no-evolution predictions for the elliptical and spiral
populations, as reported in Glazebrook et al. (1995MNRAS.275L..19G 1995MNRAS.275L..19G). A
major conclusion is that the large overdensity of merging/ peculiar/
irregular galaxies relative to the predictions of no-evolution models
(reported by Glazebrook et al. 1995MNRAS.275L..19G 1995MNRAS.275L..19G) is confirmed.
However, the shape of the faint-end (I>21.0mag) number count relation
for peculiar objects is sensitive to the large systematic
uncertainties inherent in the visual classification of these objects.
Despite this caveat, the frequency of objects showing clear evidence
for tidal interactions (e.g., tidal tails) in the HST sample is at
least 50% larger than it is among nearby galaxies, at the 2σ
level. Relatively few "chain galaxies" are seen among the sample of
peculiar objects, suggesting that these systems do not form a large
component of the peculiar galaxy population at I<22mag.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 123 508 Catalog of morphological classifications
notes.dat 103 17 Notes to table1
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- ID Identification
10- 11 I2 h RAh Right ascension (J2000)
13- 14 I2 min RAm Right ascension (J2000)
16- 19 F4.1 s RAs [0,60] Right ascension (J2000)
21 A1 --- DE- Declination sign
22- 23 I2 deg DEd Declination (J2000)
25- 26 I2 arcmin DEm Declination (J2000)
28- 31 F4.1 arcsec DEs [0,60] Declination (J2000)
33- 37 F5.2 mag Imag ? F814W magnitude
39- 43 F5.3 --- C ? Central concentration
45- 50 F6.3 --- A ? Rotational asymmetry (0 for symetrical images)
52- 53 I2 --- RSE [-2/9]? Ellis (1990, ASP Conf. vol 10, 248)
classification (1)
54 A1 --- n_RSE [*] Note detailed in file "notes.dat"
56- 57 I2 --- VDB [-2/9]? van den Bergh (1960ApJ...131..215V 1960ApJ...131..215V &
1960ApJ...131..558V 1960ApJ...131..558V) classification (1)
59- 77 A19 --- Class Classification of van den Bergh
(1960PDDO....2..159V 1960PDDO....2..159V) in DDO system
80-129 A50 --- Com VDB comment
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Note (1): the classification is a number with the following meaning:
-2 = star
-1 = compact
0 = E
1 = E/S0
2 = S0
3 = Sab
4 = S
5 = Scdm
6 = Ir
7 = peculiar
8 = merger
9 = defect
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Byte-by-byte Description of file: notes.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- ID Identification, as in table1
9 A1 --- --- [:]
11-103 A93 --- Text Text of note
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History:
* 28-Aug-1997: Prepared via OCR at CDS.
* 27-Jul-2005: Four scan errors corrected in "ID" column table1
References
Abraham et al. Paper I 1994ApJ...432...75A 1994ApJ...432...75A
(End) James Marcout, Patricia Bauer [CDS] 28-Aug-1997