FDS GALAXIES
ALANs FDS2 decompositions
LAST UPDATED 21-Nov-2019_08_43
GO DIRECTLY TO:
LIST OF GALAXIES
TABLES OF PARAMETERS
LINKS TO DIFFERENT DECOMP PAGES
Description
The Fornax Deep Survey (FDS) consists of two GTO surveys with
OmegaCAM/VST (FoCUS, PI R. Peletier; VEGAS, PI E.Iodice),
covering 21
square degree area of the Fornax main cluster in u,g,r,i bands, and 5
square-degree area in the FornaA sub-group in g,r,i bands.
This page describes multi-component decompositions carried out for 584
Fornax cluster members (including both main cluster and Fornax A).
The reduced data, and identification of cluster members are from
Venhola et al. 2018
FDS
Dwarf Galaxy Catalog .
The decompositions are made for r,g, and i band images, using Chien Pengs's GALFIT (v3.0).
The GALFIDL
package is used for visualization and running of GALFIT
decompositions.
Our galaxy list sample consists of 564 entries in Venhola et
al. 2018 Dwarf Galaxy catalog (with m_r > 12.5), plus 29
bright Fornax members (m_r < 12.5)
and one additional faint member, in
this order. Eight of the original entries in Venhola et
al. 2018 are duplicates, leading to total of 564-8+29+1=586 galaxies.
The decompositions in g,r,i -bands include
- automatic 1-component Sersic fits:
- automatic 2-component Sersic + nucleus decompositions
- human supervised multi-component decompositions
In the above decompositions the centers of the components were fixed.
In r-band, additional Sersic + nucleus decompositions were made with
free centers.
The human-supervised final
decompositions included up to 4 simultaneous components
(modeled with
GALFIT's "sersic", "expo", "edgedisk", "ferrer2", and "psf" fitting
functions, used for bulge, disk, nearly edge-on disk, bar, and
unresolved central components, respectively).
The current pages (evolved from the project's internal work pages) illustrate the preliminary steps required for starting the
decompositions
(masking, clipping, isophotal analysis, sky background
determinations) as well as results of decompositions (model & observation
comparisons, residuals).
Main page
The Fornax Decomposition Catalog
main-page (=this page) contains a list of names of all galaxies in the
sample:
the entries links to a detailed index page, showing 100
galaxies/page.
Index pages
The index pages displays for each galaxy
some info and two rows of icon-sized images (clicking on icon displays the full-size image):
< GALAXY INFO>
- Galaxy identification (follows V2018):
FDSn_x, where
n refers to field and
x is the running number
- Galaxy source:
FDS DWARF CATALOG
FDS BRIGHT
FDS DUPLICATE
FDS MISSING
- Aperture photometry:
r-band magnitude
r-band effective radius
- Galaxy class from V2018:
l = late
e = early, non-nucleated
e*= early, nucleated
Quality flags:
star
obscured
background
faint
uncertain
offcen
skyplane
2-component params:
stellar mass M*
effective radius (kpc)
Sersic index
nucleus flus ratio
g-r color
< ICONS, UPPER ROW>
1) DSS image centered at the galaxy, 10' by 10'
2) Clipped mask image (masked regions attenuated by 5 magnitudes)
3) Clipped image with iraf ellipse isophotes
4) IRAF ellipse-profiles
5) galaxy center, initial sky background estimation
6) brightness profiles in 3 bands, color profiles
7) Determination of effective radii
8) Sersic+nucleus model: 2D profile
9) Sersic+nucleus model: residuals
10) Multicomponent model: 2D profile
11) Multicomponent model: residuals
11) Multicomponent model: 1D profile
< ICONS, LOWER ROW>
1) RGB-composite image
2) Sky subtracted g image
3) Sky subtracted r image
4) Sky subtracted i image
5) Location of galaxy disk on scaling relations
(=params of Sersic component of Sersic+nucleus model)
- Central surface brightness versus stellar mass
- Effective radius
- Sersic index
- g-r color
- Nucleus/total flux ratio
- location of galaxy in Fornax
6) Determination of g-band sky background from non-masked pixels
- uppermost row: using average sky value from user-selected measurement regions
- central row: using average in user-selected elliptical annulus
- lowermost row: adding fitting a plane to background sky
7) Upper frames: g-band cumulative flux and surface brightness profiles
lower frames: sky background after subtracting a single value (left), sky plane (right)
8)-9) Same in r-band
10)-1) Same in i-band
The blue link takes to a decomposition page (20 galaxies/page), 'main' takes back to
the main galaxy list page
Decomposition pages
The decomposition page shows:
1) mask, isophote, sky-determination plots (same as on index page)
2) Two-component Sersic+PSF model: sky-plane profile, residuals, 1d-plot
3) Multi-component model: sky-plane profile, residuals, 1d-plot
A missing multicomponent model indicates that no reliable decomposition could
be done (problems with the image, no convergence, or very complicated
morphology etc.)
The links take to:
previous/next galaxy decomposition (slight delay when the page is switched)
back to galaxy index-page
back to main galaxy list
Others page
= additional decomposition pages
TABLES OF PARAMETERS
For summary tables of the parameters, see
sersic+nucleus models (mag free; long format, ascii)
sersic+nucleus models (mag,n,re free; long format, ascii)
Multi-component models g-band (long format, ascii)
Multi-component models r-band (long format, ascii)
Multi-component models i-band (long format, ascii)
Aperture photometry (long format, ascii)
LINKS
Links to alternative FDS subsamples
(e.g. galaxies ordered in stellar mass M*)
Have fun & send suggestions to heikki.salo@oulu.fi
List of galaxies
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