J/ApJ/772/135 3.6um surface brightness from S4G (Zaritsky+, 2013)
On the origin of lopsidedness in galaxies as determined from the Spitzer Survey
of Stellar Structure in Galaxies (S4G).
Zaritsky D., Salo H., Laurikainen E., Elmegreen D., Athanassoula E.,
Bosma A., Comeron S., Erroz-Ferrer S., Elmegreen B., Gadotti D.A.,
Gil de Paz A., Hinz J.L., Ho L.C., Holwerda B.W., Kim T., Knapen J.H.,
Laine J., Laine S., Madore B.F., Meidt S., Menendez-Delmestre K.,
Mizusawa T., Munoz-Mateos J.C., Regan M.W., Seibert M., Sheth K.
<Astrophys. J., 772, 135 (2013)>
=2013ApJ...772..135Z 2013ApJ...772..135Z
ADC_Keywords: Galaxies, nearby ; Morphology ; Photometry, infrared
Keywords: galaxies: fundamental parameters; galaxies: kinematics and dynamics;
galaxies: structure
Abstract:
We study the m=1 distortions (lopsidedness) in the stellar components
of 167 nearby galaxies that span a wide range of morphologies and
luminosities. We confirm the previous findings of (1) a high incidence
of lopsidedness in the stellar distributions, (2) increasing
lopsidedness as a function of radius out to at least 3.5 exponential
scale lengths, and (3) greater lopsidedness, over these radii, for
galaxies of later type and lower surface brightness. Additionally, the
magnitude of the lopsidedness (1) correlates with the character of the
spiral arms (stronger arm patterns occur in galaxies with less
lopsidedness), (2) is not correlated with the presence or absence of a
bar, or the strength of the bar when one is present, (3) is inversely
correlated to the stellar mass fraction, f*, within one radial scale
length, and (4) correlates directly with f* measured within the
radial range over which we measure lopsidedness. We interpret these
findings to mean that lopsidedness is a generic feature of galaxies
and does not, generally, depend on a rare event, such as a direct
accretion of a satellite galaxy onto the disk of the parent galaxy.
While lopsidedness may be caused by several phenomena, moderate
lopsidedness (<A1>i+<A1>o)/2<0.3) is likely to reflect halo
asymmetries to which the disk responds or a gravitationally
self-generated mode. We hypothesize that the magnitude of the stellar
response depends both on how centrally concentrated the stars are with
respect to the dark matter and whether there are enough stars in the
region of the lopsidedness that self-gravity is dynamically important.
Description:
The parent sample for this study is the S4G sample (Sheth et al. 2010,
J/PASP/122/1397), which now consists of 2352 galaxies. We observed
these galaxies using the Spitzer Space Telescope and its Infrared
Array Camera (IRAC) at 3.6 and 4.5um and reduced the data as described
by M. Regan et al. (2013, in preparation) and J. Munoz-Mateos et al.
(2013, J/ApJ/771/59). In this study, we use only the 3.6um data.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 109 167 The Sample of the S4G sample observed
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See also:
VII/237 : HYPERLEDA. I. Catalog of galaxies (Paturel+, 2003)
J/A+A/569/A91 : Optical imaging for S4G (Knapen+, 2014)
J/A+A/562/A121 : ARRAKIS: resonance rings in S4G (Comeron+ 2014)
J/AJ/147/134 : Tully-Fisher relation for S4G galaxies (Zaritsky+, 2014)
J/ApJ/771/59 : S4G face-on gal. surface brightness (Munoz-Mateos+, 2013)
J/ApJS/197/22 : The Carnegie-Irvine Galaxy Survey (GGS). II. (Li+, 2011)
J/MNRAS/416/2415 : Morphological parameters of WHISP gal. (Holwerda+, 2011)
J/ApJS/190/147 : Mid-IR galaxy morphology from S4G (Buta+, 2010)
J/PASP/122/1397 : Spitzer Survey of Stellar Structure in Gal. (Sheth+, 2010)
J/A+A/438/507 : Degree of lopsidedness for galaxies (Bournaud+, 2005)
http://irsa.ipac.caltech.edu/data/SPITZER/S4G/ : S4G data home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Galaxy Name
12- 16 F5.1 --- TType [-5/10]?=-99 Galaxy morphology from HyperLeda
18- 22 F5.1 Mpc Dist [1/84]?=-99.9 Distance from NED
24- 28 F5.1 mag 3.6Mag [-23/-11]?=-99.9 Total absolute Spitzer
3.6 micron band AB magnitude
30- 34 F5.1 pix RS [7.2/164.1] Surface brightness profile
exponential scale length (RS)
36- 39 F4.2 --- chi2 χ2 (per d.o.f.) for exponential fit
41- 42 I2 --- Arm [-1/2]? Arm classification (1)
44- 44 I1 --- Bar [0/2]? Bar classification (2)
46- 50 F5.3 --- i Average of A1/A0 for inner radial range (3)
52- 56 F5.3 --- e_i Uncertainty in i
58- 62 F5.3 --- i Average of A2/A0 for inner radial range
64- 68 F5.3 --- e_i Uncertainty in i
70- 74 F5.3 --- o Average of A1/A0 for outer radial range (3)
76- 80 F5.3 --- e_o Uncertainty in o
82- 86 F5.3 --- o Average of A2/A0 for outer radial range
88- 92 F5.3 --- e_o Uncertainty in o
94- 97 I4 deg th1.i [-464/744] Average phase of m=1 component
over inner radial range <θ1>i
99-100 I2 deg e_th1.i Uncertainty in th1.i
102-105 I4 deg th1.o [-550/761] Average phase of m=1 component
over outer radial range <θ1>o
107-109 I3 deg e_th1.o Uncertainty in th1.o
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Note (1): Arm classification as follows:
-1 = no classification possible;
0 = flocculent;
1 = multi-arm;
2 = grand design.
Note (2): Bar classification as follows:
0 = no bar;
1 = weak bar;
2 = strong bar.
Note (3): We adopt an approach of the type used by Zaritsky & Rix
(1997ApJ...477..118Z 1997ApJ...477..118Z) from the expression of the intensity
I(r,θ) = A0 + Σm Am(r) cos[m(θ-θm(r))]
The strength of the first Fourier component, , is calculated as
the average of A1/A0 between 1.5 and 2.5 disk scale lengths, RS.
See section 2.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 04-Feb-2015