image decomposition of barred galaxies and agn hosts dimitri gadotti
DESCRIPTION
Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti Max Planck Institute for Astrophysics. Outline. Tests and exercises on the reliability of image decomposition brief introduction and results for a very nearby sample (z ~ 0.005) the effects of not including bars - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/1.jpg)
Image Decomposition of Barred Galaxiesand AGN Hosts
Dimitri GadottiMax Planck Institute for Astrophysics
![Page 2: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/2.jpg)
Outline
• Tests and exercises on the reliability of image decomposition
• brief introduction and results for a very nearby sample (z ~ 0.005)
• the effects of not including bars
• the effects of not accounting for bright, type 1 AGN
• artificially redshifted images
• the effects of low physical spatial resolution
• some consequences
• the stellar mass budget in the local universe
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
![Page 3: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/3.jpg)
The BUDDA Code(de Souza, Gadotti & dos Anjos 2004)
• BUlge/Disk Decomposition Analysis v2.1 (Gadotti 2008)(http://www.mpa-garching.mpg.de/~dimitri/budda.html)
• 2D (Image Fitting)
• Bulge (Sérsic 1968)
• Disk (Freeman 1970)
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
![Page 4: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/4.jpg)
The BUDDA Code(de Souza, Gadotti & dos Anjos 2004)
• BUlge/Disk Decomposition Analysis v2.1 (Gadotti 2008)(http://www.mpa-garching.mpg.de/~dimitri/budda.html)
• 2D (Image Fitting)
• Bar• Sérsic profile• n=1: late-type bars• n<1: early-type bars
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
![Page 5: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/5.jpg)
The BUDDA Code(de Souza, Gadotti & dos Anjos 2004)
• BUlge/Disk Decomposition Analysis v2.1 (Gadotti 2008)(http://www.mpa-garching.mpg.de/~dimitri/budda.html)
• 2D (Image Fitting)
• Central Source• Moffat (1969)
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
![Page 6: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/6.jpg)
BUDDA on Very Nearby Galaxies
17 galaxies (mostly barred and some AGN) @ V & R broadbandsresolution ~ 150 pc
Gadotti & de Souza (2006)
![Page 7: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/7.jpg)
![Page 8: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/8.jpg)
Athanassoula (1992a, b)
![Page 9: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/9.jpg)
Athanassoula (1992a, b)
![Page 10: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/10.jpg)
![Page 11: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/11.jpg)
BUDDA on Very Nearby Galaxies
Kormendy (1977) relation for bulges
scaling relation for disks
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
![Page 12: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/12.jpg)
BUDDA on Very Nearby Galaxies
ellipticity peak in ellipse fitting
1 – b/a
bars might be more eccentric!
• effect is on average 20%, but a factor of 3 is also seen
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
• bar ellipticity from image fitting
![Page 13: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/13.jpg)
BUDDA on Very Nearby Galaxies
What if you don’t include bars?
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
![Page 14: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/14.jpg)
BUDDA on Very Nearby Galaxies
What if you don’t include bars?
D/T increase by 10% (average)30% maximum
B/T increase by 50% (average)100% maximum
See also Laurikainen, Salo & Buta (2005)
![Page 15: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/15.jpg)
BUDDA on Very Nearby Galaxies
What if you don’t include AGN?
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
![Page 16: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/16.jpg)
BUDDA on Artificially Redshifted Galaxies
resolution ~ 1.5 kpc
![Page 17: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/17.jpg)
BUDDA on Artificially Redshifted Galaxies
What if you go for farther galaxies?
original images
artificially redshifted imagesresolution = 1.5 kpc
1.5” @ z = 0.05 (my SDSS sample)0.75” @ z = 0.1 (MGC – Allen et al. 2006)
HST, VLT (w/ AO) @ z ≈ 1-2
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
![Page 18: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/18.jpg)
• general good agreement
• disk parameters are the most robust
• B/T overestimated on average by 5% (re ~ seeing radius…)
![Page 19: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/19.jpg)
BUDDA on Artificially Redshifted Galaxies
What if you go for farther galaxies?
• bar effect still present (even worse for re)• AGN light is diluted
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
![Page 20: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/20.jpg)
The Stellar Mass Budget at z ~ 0
• Driver et al. (2007):
• 26+/-4% (bulges)• 58+/-6% (disks)
• Correcting for:
• 5% overestimation of B/T due to poor resolution• average overestimation of (models without bars):
• B/T (50%)• D/T (10%)
• bar fraction of 70%
• Results in:
• 13.5% (bulges), 58.5% (disks), 12% (bars)
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
![Page 21: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/21.jpg)
• Bars as important as spheroids in the stellar mass budget at z ~ 0 (Gadotti 2008)
• ~ 15% in bulges
• ~ 15% in bars • ~ 15% in elliptical galaxies
• ~ 1/2 in disks
The Stellar Mass Budget at z ~ 0
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
![Page 22: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/22.jpg)
Summary
• Structural analysis of high spatial resolution images must take into account bars and type 1 AGN (otherwise B/T is overestimated wrong comparison to models)
• At lower spatial resolution AGN light is diluted but bars remain important
• Image decomposition works fine for SDSS at z ~ 0.05, but B/T is overestimated by 5% on average if re ≤ seeing
• True axial ratio of bars can only be obtained through image decomposition (ellipse fits result in rounder bars if axisymmetric component is strong)
• Bars as important as spheroids in the stellar mass budget at z ~ 0
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
![Page 23: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/23.jpg)
![Page 24: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/24.jpg)
Purec = 2
Boxyc > 2
Diskyc < 2
generalized ellipses(e.g., Athanassoula et al. 1990)
The BUDDA Code(de Souza, Gadotti & dos Anjos 2004)
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
![Page 25: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/25.jpg)
BUDDA on Very Nearby Galaxies
scale-length of disk (see also Erwin 2005)
bar semi-major axis from ellipse fitting
bar semi-major axis from image fitting
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
![Page 26: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/26.jpg)
BUDDA on Very Nearby Galaxies
comparison with Laurikainen et al. (2004) and Laurikainen, Salo & Buta (2005)
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
![Page 27: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/27.jpg)
BUDDA on Very Nearby GalaxiesTwo special cases
Gadotti & de Souza (2003): where is the disk? (fits without bar)
Rearrangement (capture) of disk stars by evolving bar (Athanassoula & Misiriotis 2002; Athanassoula 2003)
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts
![Page 28: Image Decomposition of Barred Galaxies and AGN Hosts Dimitri Gadotti](https://reader036.vdocuments.us/reader036/viewer/2022062517/56813c0f550346895da582af/html5/thumbnails/28.jpg)
BUDDA on Very Nearby GalaxiesTwo special cases
Gadotti (2008): bar growth is ~ 70%, through capture of ≈ 13% of disk stars (one and only observational constraint to date)
But best fit is achieved with Freeman (1970) type II disk
Dimitri Gadotti (MPA) – Image Decomposition of Barred Galaxies and AGN Hosts