J/MNRAS/529/499 Dwarf morphology types and parameters (Lazar+, 2024)
The morphological mix of dwarf galaxies in the nearby Universe.
Lazar I., Kaviraj S., Watkins A.E., Martin G., Bichang'a B., Jackson R.A.
<Mon. Not. R. Astron. Soc., 529, 499-518 (2024)>
=2024MNRAS.529..499L 2024MNRAS.529..499L (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, optical ; Galaxies, nearby ; Morphology ;
Photometry, CCD ; Galaxy catalogs
Keywords: galaxies: dwarf - galaxies: evolution - galaxies: formation -
galaxies: structure
Abstract:
We use a complete, unbiased sample of 257 dwarf
(108M☉<Mstar<109.5M☉) galaxies at z<0.08, in the
COSMOS field, to study the morphological mix of the dwarf population
in low-density environments. Visual inspection of extremely deep
optical images and their unsharp-masked counterparts reveals three
principal dwarf morphological classes. 43 per cent and 45 per cent of
dwarfs exhibit the traditional 'early-type' (elliptical/S0) and
'late-type' (spiral) morphologies, respectively. However, 10 per cent
populate a 'featureless' class, that lacks both the central light
concentration seen in early-types and any spiral structure - this
class is missing in the massive-galaxy regime. 14 per cent, 27 per
cent, and 19 per cent of early-type, late-type, and featureless dwarfs
respectively show evidence for interactions, which drive around 20 per
cent of the overall star formation activity in the dwarf population.
Compared to their massive counterparts, dwarf early-types show a much
lower incidence of interactions, are significantly less concentrated
and share similar rest-frame colours as dwarf late-types. This
suggests that the formation histories of dwarf and massive early-types
are different, with dwarf early-types being shaped less by
interactions and more by secular processes. The lack of large groups
or clusters in COSMOS at z<0.08, and the fact that our dwarf
morphological classes show similar local density, suggests that
featureless dwarfs in low-density environments are created via
internal baryonic feedback, rather than by environmental processes.
Finally, while interacting dwarfs can be identified using the
asymmetry parameter, it is challenging to cleanly separate early and
late-type dwarfs using traditional morphological parameters, such as
'CAS', M20, and the Gini coefficient (unlike in the massive-galaxy
regime).
Description:
Dwarf (108M☉<Mstar<109.5M☉) visual classifications and
morphological parameters (calculated for the griyz bands) in the
COSMOS field for z<0.08 used in the study. The catalogs also contain
photo-z estimates, physical properties and flags from the COSMOS2020
catalog (Weaver et al, 2022ApJS..258...11W 2022ApJS..258...11W, Cat. J/ApJS/258/11; using
Le Phare SED fitting code) and Hyper Suprime-Cam (HSC) DR3 catalog
(Aihara et al., 2022PASJ...74..247A 2022PASJ...74..247A). Detailed information related to
the visual classifications and morphological parameters available can
be seen in the paper.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
dw_class.dat 174 283 Dwarf visual classifications, photo-z values
and physical properties
dw_param.dat 117 1235 Dwarf morphological parameters
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See also:
J/ApJS/258/11 : The COSMOS2020 catalog (Weaver+, 2022)
https://hsc-release.mtk.nao.ac.jp/doc : HDC DR3 Home Page
Byte-by-byte Description of file: dw_class.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID Catalog ID (ID)
5- 21 I17 --- HSCDR3 HSC DR3 ID (IDHSCDR3)
23- 29 I7 --- COSMOS2020 COSMOS2020 ID (ID_cosmos2020)
31- 41 F11.7 deg RAdeg Right ascension (J2000) (RA)
43- 53 F11.9 deg DEdeg Declination (J2000) (DEC)
55- 56 A2 --- Morph Galaxy morphology (Morphology) (1)
58- 59 I2 --- Int-Flag [0/23] Interaction flag
(Interaction_flag) (2)
61 I1 --- Bar-Flag [0/1] Bar flag
(0 = No bar present ; 1 = Bar present)
(Bar_flag)
63- 68 F6.4 --- lpzPDF Photometric redshift (lp_zPDF) (3)
70- 75 F6.4 --- b_lpzPDF ? Photometric redshift lower 68 per cent
confidence level (lpzPDFl68) (3)
77- 82 F6.4 --- B_lpzPDF ? Photometric redshift upper 68 per cent
confidence level (lpzPDFu68) (3)
84- 90 F7.5 [Msun] loglpMassmed log Stellar mass (lpmassmed) (3)
92- 98 F7.5 [Msun] b_loglpMassmed log Stellar mass lower 68 per cent
confidence level
(lpmassmed_min68) (3)
100-106 F7.5 [Msun] B_loglpMassmed log Stellar mass upper 68 per cent
confidence level
(lpmassmed_max68) (3)
108-115 F8.5 [Msun/yr] loglpSFRmed ? log Star formation rate
(lpSFRmed) (3)
117-125 F9.5 [Msun/yr] b_loglpSFRmed ? log Star formation rate lower 68 per
cent confidence level
(lpSFRmed_min68) (3)
127-134 F8.5 [Msun/yr] B_loglpSFRmed log Star formation rate upper 68 per
cent confidence level
(lpSFRmed_max68) (3)
136-144 F9.5 mag lpGMAG G band absolute rest-frame AB magnitude
(HSC) (lp_MG) (3)
146-154 F9.5 mag lpIMAG I band absolute rest-frame AB magnitude
(HSC) (lp_MI) (3)
156 I1 --- lptype [0/1] Star flag (0 : No star ; 1 : Star)
(lp_type) (3)
158-166 F9.6 mag HSCimagAuto I band apparent magnitude (HSC)
(HSCiMAG_AUTO) (4)
168 I1 --- GextFlag [0/1]? G band extendedness flag
(0 = Not extended ; 1 = Extended)
(gextendednessvalue) (4)
170 I1 --- RextFlag [0/1]? R band extendedness flag
(0 = Not extended ; 1 = Extended)
(rextendednessvalue) (4)
172 I1 --- IextFlag [0/1]? I band extendedness flag
(0 = Not extended ; 1 = Extended)
(iextendednessvalue) (4)
174 I1 --- ZextFlag [0/1]? Z band extendedness flag
(0 = Not extended ; 1 = Extended)
(zextendednessvalue) (4)
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Note (1): Galaxy morphology code as follows:
E = Elliptical
F = Featureless
M = unresolved/HII region/star
S = Spiral
S0 = S0 galaxy
U = unsure/irregular
Note (2): Interaction flag as follows:
0 = No signs of interaction
1 = Tidal features present
2 = Internal morphology
3 = Signs of accreting another object present ;
5 = Shells present
6 = Ring present
13 = Both tidal features and signs of accreting another object present
14 = Both tidal features and dust lane present
23 = Both asymmetric morphology and signs of accreting another object present
Note (3): From Weaver et al, 2022ApJS..258...11W 2022ApJS..258...11W, Cat. J/ApJS/258/11.
Original labels for flags, photo-z values and physical properties have been
kept the same in this catalog.
Note (4): From Aihara et al., 2022PASJ...74..247A 2022PASJ...74..247A. Original labels for flags,
and magnitude have been kept the same in this catalog.
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Byte-by-byte Description of file: dw_param.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID Catalog ID (ID)
5- 11 I7 --- COSMOS2020 COSMOS2020 ID (ID_cosmos2020)
13 A1 --- Band [GRIYZ] Photometric band (Band)
15- 26 F12.9 --- C Concentration (C)
28- 39 E12.9 --- A1.5Rpetro Asymmetry calculated for an aperture up to
1.5 times the Petrosian radius (A_1.5Rpetro)
41- 52 E12.9 --- S1.5Rpetro Clumpiness calculated for an aperture up to
1.5 times the Petrosian radius (S_1.5Rpetro)
54- 64 F11.9 --- Gini Gini coefficient (GINI)
66- 77 F12.9 --- M20 M20 value (M20)
79- 91 F13.9 --- SersicN Sersic index (SERSIC_N)
93-104 F12.9 --- A1Rpetro Asymmetry calculated for an aperture up to
the Petrosian radius (A_1Rpetro)
106-117 E12.9 --- S1Rpetro Clumpiness calculated for an aperture up to
the Petrosian radius (S_1Rpetro)
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Acknowledgements:
Ilin Lazar, i.lazar(at)herts.ac.uk
(End) Ilin Lazar [Univ. of Hertfordshire], Patricia Vannier [CDS] 17-Apr-2024