J/A+A/662/A43 The Fornax Deep Survey (FDS) with VST. XII. (Venhola+, 2022)
The Fornax Deep Survey with VST.
XII: Low surface brightness dwarf galaxies in the Fornax cluster.
Venhola A., Peletier R.F., Salo H., Laurikainen E., Janz J., Haigh C.,
Wilkinson M.H.F., Iodice E., Hilker M., Mieske S., Cantiello M., Spavone M.
<Astron. Astrophys. 662, A43 (2022)>
=2022A&A...662A..43V 2022A&A...662A..43V (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Galaxies, photometry ; Photometry, SDSS
Keywords: galaxies: evolution - galaxies: dwarf -
galaxies: clusters: individual: Fornax
Abstract:
Low surface brightness (LSB) dwarf galaxies in galaxy clusters are an
interesting group of objects as their contribution to the galaxy
luminosity function and their evolutionary paths are not yet clear.
Increasing the completeness of our galaxy catalogs is crucial for
understanding these galaxies, which have effective surface
brightnesses below 23mag/arcsec2 (in optical). Progress is
continuously being made via the performance of deep observations, but
detection depth and the quantification of the completeness can also be
improved via the application of novel approaches in object detection.
For example, the Fornax Deep Survey (FDS) has revealed many faint
galaxies that can be visually detected from the images down to a
surface brightness level of 27mag/arcsec2, whereas traditional
detection methods, such as using Source Extractor (SE), fail to find
them.
In this work we use a max-tree based object detection algorithm
(Max-Tree Objects, MTO) on the FDS data in order to detect previously
undetected LSB galaxies. After extending the existing Fornax dwarf
galaxy catalogs with this sample, our goal is to understand the
evolution of LSB dwarfs in the cluster. We also study the contribution
of the newly detected galaxies to the faint end of the luminosity
function.
We test the detection completeness and parameter extraction accuracy
of MTO using simulated and real images. We then apply MTO to the FDS
images to identify LSB candidates. The identified objects are fitted
with 2D Sersic models using GALFIT and classified as imaging
artifacts, likely cluster members, or background galaxies based on
their morphological appearance, colors, and structure.
With MTO, we are able to increase the completeness of our earlier FDS
dwarf catalog (FDSDC) 0.5-1mag deeper in terms of total magnitude and
surface brightness. Due to the increased accuracy in measuring sizes
of the detected objects, we also add many small galaxies to the
catalog that were previously excluded as their outer parts had been
missed in detection. We detect 265 new LSB dwarf galaxies in the
Fornax cluster, which increases the total number of known dwarfs in
Fornax to 821. Using the whole cluster dwarf galaxy population, we
show that the luminosity function has a faint-end slope of
α=-1.380.02. We compare the obtained luminosity function with
different environments studied earlier using deep data but do not find
any significant differences. On the other hand, the Fornax-like
simulated clusters in the IllustrisTNG cosmological simulation have
shallower slopes than found in the observational data. We also find
several trends in the galaxy colors, structure, and morphology that
support the idea that the number of LSB galaxies is higher in the
cluster center due to tidal forces and the age dimming of the stellar
populations. The same result also holds for the subgroup of large LSB
galaxies, so-called ultra-diffuse galaxies.
Description:
Photometric parameters of the likely Fornax galaxies that were not
identified by Venhola et al. (2018A&A...620A.165V 2018A&A...620A.165V, Cat.
J/A+A/620/A165).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb1.dat 136 265 Dwarf galaxy catalog that includes likely
cluster galaxies
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See also:
J/A+A/608/A142 : Fornax Deep Survey with VST. LSB galaxies (Venhola+, 2017)
J/A+A/620/A165 : Fornax Deep Survey with VST. dwarf galaxies (Venhola+, 2018)
J/A+A/623/A1 : Fornax Deep Survey with VST. Isophote fit (Iodice+, 2019)
J/A+A/639/A136 : Fornax Deep Survey with VST. (Cantiello+, 2020)
J/A+A/647/A100 : Fornax Deep Survey with VST. (Su+, 2021)
Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Target Target name (FDSLSBNNN)
11- 17 F7.4 deg RAdeg Right Ascension (ICRS)
19- 26 F8.4 deg DEdeg Declination (ICRS)
28- 31 F4.2 --- b/a Axis-ratio
33- 36 F4.2 --- e_b/a Axis-ratio uncertainty
38- 42 F5.1 deg theta Position angle
44- 47 F4.1 deg e_theta Position angle uncertainty
49- 52 F4.1 mag r'fitmag r'-band magnitude from Sersic fit
54- 56 F3.1 mag e_r'fitmag r'-band magnitude from Sersic fit uncertainty
58- 61 F4.1 arcsec Re Effective radius
63- 66 F4.1 arcsec e_Re Effective radius uncertainty
68- 71 F4.1 --- n Sersic index
73- 75 F3.1 --- e_n Sersic index uncertainty
77- 81 F5.2 mag u'mag ?=-1 u'-band magnitude within effective
radius
83- 87 F5.2 mag e_u'mag ?=-1 u'-band magnitude within effective
radius uncertainty
89- 93 F5.2 mag g'mag g'-band magnitude within effective radius
95- 98 F4.2 mag e_g'mag g'-band magnitude within effective radius
uncertainty
100-104 F5.2 mag r'mag r'-band magnitude within effective radius
106-109 F4.2 mag e_r'mag r'-band magnitude within effective radius
uncertainty
111-115 F5.2 mag i'mag i'-band magnitude within effective radius
117-120 F4.2 mag e_i'mag i'-band magnitude within effective radius
uncertainty
122-126 F5.1 --- C ?=-99 Concentration parameter
128-133 F6.2 --- RFF ?=-99 Residual Flux fraction
135-136 A2 --- Morph Tidal morphology (1)
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Note (1): Tidal morphology code as follows:
1 = regular
2 = slightly disturbed
3 = disturbed
4 = uncertain
* = object has a nucleus
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Acknowledgements:
Aku Venhola, aku.venhola(at)oulu.fi
References:
Iodice et al., Paper I 2016ApJ...820...42I 2016ApJ...820...42I
Iodice et al., Paper II 2017ApJ...839...21I 2017ApJ...839...21I
Venhola et al., Paper III 2017A&A...608A.142V 2017A&A...608A.142V, Cat. J/A+A/608/A142
Venhola et al., Paper IV 2018A&A...620A.165V 2018A&A...620A.165V, Cat. J/A+A/620/A165
Iodice et al., Paper V 2019A&A...623A...1I 2019A&A...623A...1I, Cat. J/A+A/623/A1
Venhola et al., Paper VI 2019A&A...625A.143V 2019A&A...625A.143V
Raj et al., Paper VII 2019A&A...628A...4R 2019A&A...628A...4R
Spavone et al., Paper VIII 2020A&A...639A..14S 2020A&A...639A..14S
Cantiello et al., Paper IX 2020A&A...639A.136C 2020A&A...639A.136C, Cat. J/A+A/639/A136
Raj et al., Paper X 2020A&A...640A.137R 2020A&A...640A.137R
Su et al., Paper XI 2021A&A...647A.100S 2021A&A...647A.100S, Cat. J/A+A/647/A100
(End) Patricia Vannier [CDS] 08-Jun-2022