J/A+A/610/A5 Stellar structure models of edge-on galaxies (Comeron+, 2018)
The reports of thick discs' death are greatly exaggerated.
Thick discs are NOT artefacts caused by diffuse scattered light.
Comeron S., Salo H., Knapen J.H.
<Astron. Astrophys. 610, A5 (2018)>
=2018A&A...610A...5C 2018A&A...610A...5C (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, IR ; Galaxies, nearby ; Galaxies, photometry
Keywords: methods: data analysis - methods: observational -
galaxies: spiral - galaxies: structure
Abstract:
Recent studies have made the community aware of the importance of
accounting for scattered light when examining low-surface-brightness
galaxy features such as thick discs. In our past studies of the thick
discs of edge-on galaxies in the Spitzer Survey of Stellar Structure
in Galaxies - the S4G - we modelled the point spread function as a
Gaussian. In this paper we re- examine our results using a revised
point spread function model that accounts for extended wings out to
more than 2.5arcmin. We study the 3.6micron images of 141 edge-on
galaxies from the S4G and its early-type galaxy extension. Thus, we
more than double the samples examined in our past studies. We
decompose the surface-brightness profiles of the galaxies
perpendicular to their mid-planes assuming that discs are made of two
stellar discs in hydrostatic equilibrium. We decompose the axial
surface- brightness profiles of galaxies to model the central mass
concentration - described by a Sersic function - and the disc -
described by a broken exponential disc seen edge-on. Our improved
treatment fully confirms the ubiquitous occurrence of thick discs. The
main difference between our current fits and those presented in our
previous papers is that now the scattered light from the thin disc
dominates the surface brightness at levels below ∼26mag/arcsec2. We
stress that those extended thin disc tails are not physical, but pure
scattered light. This change, however, does not drastically affect any
of our previously presented results: 1) Thick discs are nearly
ubiquitous. They are not an artefact caused by scattered light as has
been suggested elsewhere. 2) Thick discs have masses comparable to
those of thin discs in low-mass galaxies - with circular velocities
vc<120km/s - whereas they are typically less massive than the thin
discs in high-mass galaxies. 3) Thick discs and central mass
concentrations seem to have formed at the same epoch from a common
material reservoir. 4) Approximately 50% of the up-bending breaks in
face-on galaxies are caused by the superposition of a thin and a thick
disc where the scale-length of the latter is the largest.
Description:
Appendice B and C. Information on the studied edge-on galaxies and
their decompositions.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb.dat 286 124 Galaxies with at least two distinct discs
tablec.dat 286 17 Galaxies that do not have at least two distinct
discs
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See also:
J/A+AS/93/255 : Axial ratios of edge-on spirals (Guthrie 1992)
J/PAZh/27/250 : Rotation curves for 135 edge-on galaxies (Makarov+, 2001)
J/A+A/389/795 : Vertical structure of edge-on galaxies (Bizyaev+, 2002)
J/A+A/435/459 : HI data of edge-on spiral galaxies (Huchtmeier+, 2005)
J/A+A/445/765 : A Catalog of Edge-on Disk Galaxies (Kautsch+, 2006)
J/ApJ/702/1567 : Structure of 2MASS edge-on galaxies (Bizyaev+, 2009)
J/ApJ/787/24 : Structural parameters of true edge-on galaxies (Bizyaev+ 2014)
Byte-by-byte Description of file:table?.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- ID Galaxy name
11- 15 F5.1 arcsec r25 Isophotal 25mag/arcsec2 radius in the
B-band from HyperLeda
17- 21 F5.1 deg PA Majot axis position angle
23- 29 F7.3 mag M3.6 Absolute 3.6um magnitude in the AB system (1)
31- 35 F5.2 Mpc Dist Galaxy distance
37 I1 --- r_Dist [1/5] Source of the galaxy distance (2)
39- 41 I3 km/s vc Galaxy maximum circular velocity
43- 44 I2 --- r_vc [1/19] Source of the galaxy maximum circular
velocity (3)
46- 49 F4.1 arcsec zc1 ?=- Lower limit of the region where most of
the light is emitted by the thick disc
51- 55 F5.1 arcsec zc2 ?=- Higher limit of the region where most of
the light is emitted by the thick disc
57- 61 F5.1 arcsec zu Height where the surface brightness is
26mag/arcsec2
63- 66 F4.2 arcsec rCMC ?=- Scale size of the central mass
concentration (CMC)
68- 71 F4.2 arcsec nCMC ?=- Sersic index of the central mass
concentration (CMC)
73- 86 A14 --- Ttot Axial surface brightness profile type of the
whole disc
88- 98 F11.1 arcsec h1tot Scale-length of the first exponential
section of the whole disc
100-108 F9.1 arcsec h2tot ?=- Scale-length of the second exponential
section of the whole disc
110-114 F5.1 arcsec h3tot ?=- Scale-length of the third exponential
section of the whole disc
116-120 F5.1 arcsec h4tot ?=- Scale-length of the fourth exponential
section of the whole disc
122-126 F5.1 arcsec r12tot ?=- Radius of the break between the first and
the second exponential sections of the whole
disc
128-132 F5.1 arcsec r23tot ?=- Radius of the break between the second
and the third exponential sections of the
whole disc
134-138 F5.1 arcsec r34tot ?=- Radius of the break between the third and
the fourth exponential sections of the whole
disc
140-153 A14 --- Tthin Axial surface brightness profile type of the
thin disc
155-164 F10.1 arcsec h1thin ?=- Scale-length of the first exponential
section of the thin disc
166-175 F10.1 arcsec h2thin ?=- Scale-length of the second exponential
section of the thin disc
177-181 F5.1 arcsec h3thin ?=- Scale-length of the third exponential
section of the thin disc
183-187 F5.1 arcsec h4thin ?=- Scale-length of the fourth exponential
section of the thin disc
189-193 F5.1 arcsec r12thin ?=- Radius of the break between the first and
the second exponential sections of the thin
disc
195-199 F5.1 arcsec r23thin ?=- Radius of the break between the second
and the third exponential sections of the
thin disc
201-205 F5.1 arcsec r34thin ?=- Radius of the break between the third and
the fourth exponential sections of the thin
disc
207-216 A10 --- Tthick Axial surface brightness profile type of the
thick disc
218-227 F10.1 arcsec h1thick ?=- Scale-length of the first exponential
section of the thick disc
229-235 F7.1 arcsec h2thick ?=- Scale-length of the second exponential
section of the thick disc
237-240 F4.1 arcsec h3thick ?=- Scale-length of the third exponential
section of the thick disc
242-246 F5.1 arcsec r12thick ?=- Radius of the break between the first and
the second exponential sections of the thick
disc
248-252 F5.1 arcsec r23thick ?=- Radius of the break between the second
and the third exponential sections of the
thick disc
254-258 F5.2 10+9Msun GasM Gas disc mass
260-264 F5.2 10+9Msun ThinM Thin disc mass
266-270 F5.2 10+9Msun ThickM Thick disc mass
272-276 F5.2 10+9Msun CMCM Central mass concentration (CMC) mass
278-281 F4.1 arcsec sc-thin Thin disc scale-height
283-286 F4.1 arcsec sc-thick Thick disc scale-height
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Note (1): From Munoz-Mateos et al. (2015ApJS..219....3M 2015ApJS..219....3M) and this paper.
Note (2): Distance references as follows:
1 = CF1 (Tully et al., 2008, Cat. J/ApJ/676/184)
2 = CF3 Tully et al. (2016, Cat. J/AJ/152/50)
3 = SFI++ Springob et al. (2007, Cat. J/ApJS/172/599)
4 = Theureau et al. (2007, Cat. J/A+A/465/71)
5 = Hubble-Lemaitre flow distances with respect to the cosmic microwave
background assuming a Hubble-Lemaitre constant of H0=75km/s.
Note (3): Circular velocity references as follows:
1 = Springob et al. (2005ApJS..160..149S 2005ApJS..160..149S, Cat VIII/77)
2 = Theureau et al. (2006, ASPCS, 351, 429)
3 = Courtois et al. (2009, Cat. J/AJ/138/1938)
4 = pre-digital measurements compiled in the EDD
5 = Krumm & Salpeter (1976ApJ...208L...7K 1976ApJ...208L...7K)
6 = Balkowski & Chamaraux (1981A&A....97..223B 1981A&A....97..223B)
7 = Richter & Huchtmeier (1987A&AS...68..427R 1987A&AS...68..427R)
8 = Haynes et al. (1990AJ.....99.1740H 1990AJ.....99.1740H)
9 = D'Onofrio et al. (1995, Cat. J/A+A/296/319)
10 = Mathewson & Ford (1996, Cat J/ApJS/107/97)
11 = Simien & Prugniel (1997, Cat J/A+AS/126/15, Cat. J/A+AS/126/519)
12 = Simien & Prugniel (1998, Cat J/A+AS/131/287)
13 = Rubin et al. (1999AJ....118..236R 1999AJ....118..236R)
14 = Simien & Prugniel (2000, Cat J/A+AS/145/263)
15 = Karachentsev et al. (2004, Cat. J/AJ/127/2031)
16 = Chung & Bureau (2004AJ....127.3192C 2004AJ....127.3192C)
17 = Meyer et al. (2004MNRAS.350.1195M 2004MNRAS.350.1195M, Cat. VIII/73)
18 = Bedregal et al. (2006MNRAS.371.1912B 2006MNRAS.371.1912B)
19 = ATLAS3D (Cappellari et al. 2011, Cat J/MNRAS/413/813;
Krajnovic et al. 2011MNRAS.414.2923K 2011MNRAS.414.2923K)
The recession velocities are taken from the NED.
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Acknowledgements:
Sebastien Comeron, seb.comeron(at)gmail.com
(End) S. Comeron [Univ. Oulu, Finland], P. Vannier [CDS] 29-Nov-2017