J/ApJ/821/114 The CGS. IV. Elliptical galaxies colors (Huang+, 2016)
The Carnegie-Irvine Galaxy Survey.
IV. A method to determine the average mass ratio of mergers that built massive
elliptical galaxies.
Huang S., Ho L.C., Peng C.Y., Li Z.-Y., Barth A.J.
<Astrophys. J., 821, 114-114 (2016)>
=2016ApJ...821..114H 2016ApJ...821..114H (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, photometry ; Morphology ; Surveys
Keywords: galaxies: elliptical and lenticular, cD; galaxies: formation;
galaxies: photometry; galaxies: structure
Abstract:
Many recent observations and numerical simulations suggest that nearby
massive, early-type galaxies (ETGs) were formed through a "two-phase"
process. In the proposed second phase, the extended stellar envelope
was accumulated through many dry mergers. However, details of the past
merger history of present-day ellipticals, such as the typical merger
mass ratio, are difficult to constrain observationally. Within the
context and assumptions of the two-phase formation scenario, we
propose a straightforward method, using photometric data alone, to
estimate the average mass ratio of mergers that contributed to the
build-up of massive elliptical galaxies. We study a sample of nearby
massive elliptical galaxies selected from the Carnegie-Irvine Galaxy
Survey, using two-dimensional analysis to decompose their light
distribution into an inner, denser component plus an extended, outer
envelope, each having a different optical color. The combination of
these two substructures accurately recovers the negative color
gradient exhibited by the galaxy as whole. The color difference
between the two components (<Δ(B-V)≳0.10mag;
<Δ(B-R)≳0.14mag), based on the slope of the M*-color relation
for nearby ETGs, can be translated into an estimate of the average
mass ratio of the mergers. The rough estimate, 1:5 to 1:10, is
consistent with the expectation of the two-phase formation scenario,
suggesting that minor mergers were largely responsible for building up
the outer stellar envelopes of present-day massive ellipticals. With
the help of accurate photometry, large sample sizes and more choices
of colors promised by ongoing and future surveys, the approach
proposed here can provide more insights into the growth of massive
galaxies during the last few Gyr.
Description:
This work uses the multi-band optical images of nearby ellipticals
from the Carnegie-Irvine Galaxy Survey (CGS; Ho et al. 2011,
J/ApJS/197/21, Paper I). The observations were made using the 100 inch
du Pont telescope at Las Campanas Observatory to provide high-quality
Johnson/Kron-Cousins BVRI images during the period 2003 February to
2006 June.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 75 240 Summary of color measurements for three-component
Sersic models
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See also:
J/A+A/563/A92 : VIPERS: galaxy colours and luminosity function (Fritz+, 2014)
J/ApJS/210/3 : SDSS bulge, disk & stellar mass estimates (Mendel+, 2014)
J/MNRAS/435/623 : Multiwavelength measurement of galaxy structure (Vika, 2013)
J/ApJ/766/109 : Color/age/metallicity gradients of E galaxies (Kim+, 2013)
J/ApJ/749/121 : Surface brightness profiles of z=2 galaxies (Szomoru+, 2012)
J/ApJS/197/22 : The Carnegie-Irvine Galaxy Survey (GGS). II. (Li+, 2011)
J/ApJS/197/21 : The Carnegie-Irvine Galaxy Survey (CGS). I. (Ho+, 2011)
J/ApJS/196/11 : Bulge+disk decompositions of SDSS galaxies (Simard+, 2011)
J/A+A/525/A157 : SDSS automated morphology classif. (Huertas-Company+, 2011)
J/A+A/478/353 : Structural properties of disk galaxies (Mendez-Abreu+, 2008)
J/AJ/131/1288 : Composite spectra of early-type galaxies (Bernardi+, 2006)
J/A+A/441/451 : UBVRIJHK photometry of E-type galaxies (Michard+, 2005)
J/AJ/129/2138 : Centers of early-type galaxies with HST (Lauer+, 2005)
J/AJ/100/1091 : UBR photometry of 39 elliptical galaxies (Peletier+ 1990)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Galaxy name
14- 18 F5.2 [Msun] logMTot [10.3/11.8] Total stellar mass of the galaxy
20- 23 F4.2 [Msun] e_logMTot [0.04/0.3] Uncertainty in logMTot
25- 29 F5.2 [Msun] logMIn [9.9/11.6] Stellar mass of the inner component
31- 35 F5.2 [Msun] logMOut [9.8/11.7] Stellar mass of the outer component
37- 43 A7 --- Col Type of color (B i-V i or B i-R i) (1)
45- 49 A5 --- f_Col Flag on color ("free" or "fixed") (1)
51- 54 F4.2 mag Cen [0.6/2.3] Color of the center component
56- 59 F4.2 mag Inter [0.5/2.1] Color of the intermediate component
61- 64 F4.2 mag Outer [0.5/2] Color of the outer component
66- 69 F4.2 mag Inner [0.6/2.1] Color of the inner component
71- 75 F5.2 mag dCol [-0.09/0.4] Color difference between the
inner and outer components
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Note (1): For each galaxy, the B-V and B-R color information with fixed
or free sky background are shown in different rows.
The free-background ones are recommended.
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History:
From electronic version of the journal
References:
Ho et al. Paper I. 2011ApJS..197...21H 2011ApJS..197...21H Cat. J/ApJS/197/21
Li et al. Paper II. 2011ApJS..197...22L 2011ApJS..197...22L Cat. J/ApJS/197/22
Huang et al. Paper III. 2013ApJ...766...47H 2013ApJ...766...47H
Huang et al. Paper IV. 2016ApJ...821..114H 2016ApJ...821..114H This catalog
Li et al. Paper V. 2017ApJ...845...87L 2017ApJ...845...87L Cat. J/ApJ/845/87
Yu et al. Paper VI. 2018ApJ...862...13Y 2018ApJ...862...13Y Cat. J/ApJ/862/13
Gao et al. Paper VII. 2018ApJ...862..100G 2018ApJ...862..100G Cat. J/ApJ/862/100
Gao et al. Paper VIII. 2019ApJS..244...34G 2019ApJS..244...34G Cat. J/ApJS/244/34
Gao et al. Paper IX. 2020ApJS..247...20G 2020ApJS..247...20G Cat. J/ApJS/247/20
Gao et al. Paper X. 2022ApJS..262...54G 2022ApJS..262...54G Cat. J/ApJS/262/54
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 28-Jul-2016