J/AJ/126/1183 Major galaxy mergers at z≲3 (Conselice+, 2003)
A direct measurement of major galaxy mergers at z≲3.
Conselice C.J., Bershady M.A., Dickinson M., Papovich C.
<Astron. J., 126, 1183-1207 (2003)>
=2003AJ....126.1183C 2003AJ....126.1183C
ADC_Keywords: Galaxies, photometry ; Redshifts
Keywords: galaxies: evolution - galaxies: formation - galaxies: interactions
Abstract:
This paper presents direct evidence for hierarchical galaxy assembly
out to redshifts z∼3. We identify major mergers using the
model-independent CAS (concentration, asymmetry, clumpiness) physical
morphological system on galaxies detected, and photometrically
selected, in the WFPC2 and NICMOS Hubble Deep Field North. We
specifically use the asymmetric distributions of rest-frame optical
light measured through the asymmetry parameter (A) to determine the
fraction of galaxies undergoing major mergers as a function of
redshift (z), stellar mass (M*), and absolute magnitude (MB).
Description:
The images we use for our morphological analyses were acquired with
the Hubble Space Telescope as part of the Hubble Deep Field North
optical and near-infrared campaigns. Optical data from the Wide Field
Planetary Camera 2 (WFPC2) of the HDF-N are combined with
near-infrared (NIR) observations of the same field taken with the Near
Infrared Camera and Multi-Object Spectrometer (NICMOS). The optical
data consist of images in the WFPC2 filters: F300W (U), F450W (B),
F606W (V), and F814W (I). The NICMOS HDF-N images were taken in 1998
June with observations in the F110W (J) and F160W (H) near-infrared
bands. We also use a deep K-band image obtained with the Kitt Peak
Mayall 4m telescope.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 61 43 Major merger candidates in the Hubble Deep Field North
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See also:
J/AJ/127/131 : NICMOS early-type galaxies (Stanford+, 2004)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- HNM HNM number (1)
6- 7 I2 h RAh Right ascension (J2000.0)
9- 10 I2 min RAm Right ascension (J2000.0)
12- 15 F4.1 s RAs Right ascension (J2000.0)
17 A1 --- DE- Declination sign (J2000.0)
18- 19 I2 deg DEd Declination (J2000.0)
21- 22 I2 arcmin DEm Declination (J2000.0)
24- 27 F4.1 arcsec DEs Declination (J2000.0)
29- 32 F4.2 --- z Redshift (2)
34- 37 F4.2 mag A(B)rest Rest-frame B-band asymmetries, which have been
corrected for systematic redshift effects
39- 42 F4.2 mag e_A(B)rest rms uncertainty on A(B)rest
44- 49 F6.2 mag BMAG Absolute B magnitude
51- 55 F5.2 mag (B-V)rest ? Rest-frame Johnson B-V colour index
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Note (1): These are the galaxies with rest-frame B-band asymmetries
greater than 0.35 after correcting for systematic effects based on our
simulations. We also list only those systems at z>2 that are brighter
than MB=-20, as the identify of a major merger for fainter galaxies
at z>2 becomes less certain, and the implied merger fraction is more
of a statistical quantity.
Note (2): Redshifts are a mix of spectroscopic, when available,
otherwise photometric
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History:
From electronic version of the journal
(End) James Marcout, Patricia Vannier [CDS] 02-Jul-2004