J/A+A/596/A25 Disc breaks across masses and wavelengths (Laine+, 2016)
Influence of galaxy stellar mass and observed wavelength on disc breaks in
S4G, NIRS0S, and SDSS data.
Laine J., Laurikainen E., Salo H.
<Astron. Astrophys. 596, A25 (2016)>
=2016A&A...596A..25L 2016A&A...596A..25L (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Morphology
Keywords: galaxies: evolution - galaxies: structure - galaxies: statistics
Abstract:
Breaks in the surface brightness profiles in the outer regions of
galactic discs are thought to have formed by various internal (e.g.
bar resonances) and external (e.g. galaxy merging) processes. By
studying the disc breaks we aim to better understand what processes
are responsible for the evolution of the outer discs of galaxies, and
galaxies in general.
We use a large well-defined sample to study how common the disc breaks
are, and whether their properties depend on galaxy mass. By using both
optical and infrared data we study whether the observed wavelength
affects the break features as a function of galaxy mass and Hubble
type.
We studied the properties of galaxy discs using radial surface
brightness profiles of 753 galaxies, obtained from the 3.6um images
of the Spitzer Survey of Stellar Structure in Galaxies (S4G), and the
Ks-band data from the Near InfraRed S0-Sa galaxy Survey (NIRS0S),
covering a wide range of galaxy morphologies (-2≤T≤9) and
stellar masses (8.5≲log10 (M*/M☉)≲11). In addition, optical
Sloan Digital Sky Survey (SDSS) or Liverpool telescope data was used
for 480 of these galaxies.
We find that in low-mass galaxies the single exponential profiles
(Type I) are most common, and that their fraction decreases with
increasing galaxy stellar mass. The fraction of down-bending (Type II)
profiles increases with stellar mass, possibly due to more common
occurrence of bar resonance structures. The up-bending (Type III)
profiles are also more common in massive galaxies. The observed
wavelength affects the scalelength of the disc of every profile type.
Especially the scalelength of the inner disc (hi) of Type II profiles
increases from infrared to u-band on average by a factor of ∼2.2.
Consistent with the previous studies, but with a higher statistical
significance, we find that Type II outer disc scalelengths (ho) in
late-type and low mass galaxies (T>4, log10(M*/M☉)≲10.5) are
shorter in bluer wavelengths, possibly due to stellar radial migration
populating the outer discs with older stars. In Type III profiles h_o
are larger in the u band, hinting to the presence of young stellar
population in the outer disc. While the observed wavelength affects
the disc parameters, it does not significantly affect the profile type
classification in our sample. Our results indicate that the observed
wavelength is a significant factor when determining the profile types
in very low mass dwarf galaxies, for which more Type II profiles have
been previously found using optical data.
Description:
Table 1 contains basic properties of the sample galaxies, as well as
the wavelength bands available for each galaxy.
Table 3 contains the obtained disc profile parameters of each galaxy,
and in all available wavelength bands.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 75 753 Properties of the sample galaxies
table3.dat 113 3186 Disc profile parameters
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See also:
J/PASP/122/1397 : Spitzer Survey of Stellar Structure in Galaxies (Sheth+ 2010)
J/A+A/569/A91 : Optical imaging for S4G (Knapen+, 2014)
J/ApJS/217/32 : S4G galaxy morphologies in the CVRHS system (Buta+, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Galaxy Galaxy name
12- 17 A6 --- Survey The survey from which the galaxy is taken (1)
19- 31 A13 --- Bands Wavelength bands available for the galaxy (2)
33- 36 F4.1 --- TT Numerical morphology code (3)
38- 41 F4.1 [Msun] logM* Stellar mass of the galaxy, from Munoz-Mateos
et al. (2014ApJ...783...26V 2014ApJ...783...26V)
43- 46 F4.1 Mpc Dist Distance to the galaxy
48- 51 F4.1 Mpc e_Dist ?=- Uncertainty of the galaxy distance
53- 57 F5.1 arcsec Ropt B-band 25mag/arcsec2 radius of the galaxy
from HyperLeda
59- 63 F5.1 arcsec R24IR IR(3.6) 24mag/arcsec2 radius of the galaxy
65- 70 F6.1 deg PA [] Position angle of the outer disc
72- 75 F4.2 --- ell Ellipticity of the outer disc
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Note (1): S4G (Sheth et al., 2010, Cat. J/PASP/122/1397) or
NIRS0S (Laurikainen et al., 2011MNRAS.418.1452L 2011MNRAS.418.1452L).
Note (2): from S4G (Sheth et al., 2010, Cat. J/PASP/122/1397),
NIR0S (Laurikainen et al., 2011MNRAS.418.1452L 2011MNRAS.418.1452L) or
Knapen et al. (2014, Cat. J/A+A/569/A91).
Note (3): from Laurikainen et al. (2011MNRAS.418.1452L 2011MNRAS.418.1452L) for NIRS0S data,
(Laurikainen et al., 2011MNRAS.418.1452L 2011MNRAS.418.1452L) and Buta et al.
(2015, Cat. J/ApJS/217/32) for S4G data.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Galaxy Galaxy name (1)
12- 14 A3 --- Band Wavelength band
16- 28 A13 --- Type ?=- Profile type (2)
30- 34 F5.1 arcsec Rin ?=- Inner radius of the disc profile
fit region
36- 40 F5.1 arcsec Rout ?=- Outer radius of the disc profile
fit region
42- 45 F4.1 mag/arcsec2 MuRout ?=- Surface brightness at Rout
47- 51 F5.1 arcsec Rbr ?=- Break radius
53- 56 F4.1 arcsec e_Rbr ?=- Uncertainty of Rbr
58- 62 F5.2 mag/arcsec2 MuRbr ?=- Surface brightness at Rbr
64- 67 F4.2 mag/arcsec2 e_MuRbr ?=- Uncertainty of MuRbr
69- 73 F5.2 mag/arcsec2 mui0 ?=- Extrapolated central surface
brightness of the inner disc (3)
75- 78 F4.2 mag/arcsec2 e_mui0 ?=- Uncertainty of mui0
80- 84 F5.1 arcsec hi ?=- Inner disc scalelength (3)
86- 90 F5.1 arcsec e_hi ?=- Uncertainty of hi
92- 96 F5.2 mag/arcsec2 muo0 ?=- Extrapolated central surface
brightness of the outer disc
98-101 F4.2 mag/arcsec2 e_muo0 ?=- Uncertainty of muo0
103-107 F5.1 arcsec ho ?=- Outer disc scalelength
109-113 F5.1 arcsec e_ho ?=- Uncertainty of ho
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Note (1): If a galaxy has two lines with the same wavelength band in this file
then the latter line corresponds to another outer break
Note (2): the classification of profile Types is:
I = single exponential disc
II = downbending dual-exponential disc (outer disc has a lower
scalelength than the inner disc)
II.i = the break is at or inside the bar radius
III = upbending dual-exponential disc (outer disc has a larger
scalelength than the inner disc)
Note (3): for Type I and II.i discs, this is the main disc.
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Acknowledgements:
Jarkko Laine, jarkko.laine(at)oulu.fi
(End) Patricia Vannier [CDS] 06-Oct-2016