1. Quasars and Low Surface Brightness Galaxies as Probes of Dark Matter
Bild på kvasar och LSBG?
Erik Zackrisson

2. Outline Dark matter Quasars Low Surface Brightness Galaxies
Dark matter halos
Baryonic and non-baryonic dark matter
Cold dark matter
Quasars
Gravitational lensing
Redshift
Low Surface Brightness Galaxies
Rotation curves
Summary of Results

3. Dark Matter
Dark matter
Luminous matter

4. First detection of dark matter
Top 10 most important problems in science
Fritz Zwicky (1933): Dark matter in the Coma Cluster

5. The Dark Matter Problem
~2%
(Luminous)
~98%
(Dark)

6. Dark Matter Halos I
Galaxy  Stars + Gas + Dust + Supermassive Black Hole + Dark Matter

7. Dark Matter Halos II Luminous galaxy Dark halo
Not a ring – a filled sphere!
Dark halo

8. Baryonic & Non-Baryonic Dark Matter
Baryonic matter: ~15%
Example: Stars, gas clouds, planets…
Missing: ~ 35%
Non-baryonic matter: ~85%
Example: Axions, neutralinos,
primordial black holes…
Missing: ~ 100%
Best model: Cold Dark Matter (CDM)

9. Cold dark matter and the evolution of structure

10. Cold dark matter and the evolution of structure II

11. Cold Dark Matter Halos Central density cusp predicted by
Observed
Density
Density profiles R
Dark matter halo

12. Quasars

14. Gravitational lensing

15. Gravitational lensing II

16. Microlensing Made Simple
Microlensing more complicated than other forms of lensing because ML is time-dependent
Opportunity and challenge (when both distance and velocity unknown)
Obs! Fel bild!

17. Microlensing Made Simple II

18. Claim: The long-term optical variability of quasars is quased by microlensing
Similar claim by Zakharov for X-ray variability
Hawkins, M.R.S. (1993, 1996, 1997, 2000, 2001, 2002, 2003)

19. The dark matter puzzle solved?
Mcompact 10-3 Msolar
Almost all of the dark matter in this form
Primordial black holes?
Bild på Hawkins bok

20. Expansion of the Universe
Viktigt inför presentationen av Big Bang
Den jäsande degen…
Inte bara verkar universum växa, expansionen verkar gå snabbare och snabbare också – expansionen accelererar

21. Redshifts High z  Large distance Low z  Small distance
Spooky picture…
High z  Large distance
Low z  Small distance

22. Claims of non-cosmological redshiftsz1 z2
Low-z galaxy with pairs of high-z quasars (with z1z2) aligned along minor axis
Low-z galaxy surrounded by overdensity of high-z quasars

23. Ejection scenarios ? ? ? ? ? New galaxy (?), very low redshift (z1)
Bright quasar, low redshift (>z1)
Faint quasar, high redshift (>>z1)
Local galaxy, very low redshift (z1)

24. Low Surface Brightness Galaxies
Examples of
Target Galaxies
The Very Large Telescope

25. The Central Mass Budget
High Surface
Brightness Galaxies
Low Surface
Brightness Galaxies
Dark
matter
Luminous
matter
Dark
matter
Luminous
matter

26. Rotation Curves Spectroscopy → Rotation Curve → Density Profile Vrot
CDM
prediction
Vrot
Density
Observed
Radius
Radius
Spectroscopy → Rotation Curve → Density Profile

27. Results
Paper I
Uncertainties in the typical quasar size  Quasar variability cannot easily be used to constrain dark matter at the current time
Paper II
Microlensing cannot explain the long-term optical variability of quasars – Hawkins is wrong!
Paper III
Non-cosmological redshift scenarios involving quasar ejection can be tested with observations of quasar host galaxies made a small telescope

28. Results II
Paper IV
The bluest low surface brightness galaxies can be used to test hierarchical galaxy formation models – provided that we can derive their ages
The star formation rate of the bluest low surface brightness galaxies cannot have been constant or increasing – unless the stellar initial mass function is unusual
Paper V
The density profiles of the dark halos surrounding the bluest low surface brightness galaxies are in conflict with the Cold Dark Matter predictions

29. Errata Spikblad: Polhemssalen  Polhemsalen
Page v: optical long-term  long-term optical
Page 3: as the ray crossed  as its ray grazed
Page 24 (twice): reflectance  reflection
Page 33: z  2—3  z  2—4
Page 35: the latter variations  these variations
Page 35: hoever are  are however
Page 37: by fast rise  by a fast rise
Page 44: 1012—1014 m  1012—31013 m
Page 56: disk by  disk is given by
Page 69: ett par procent  några få procent
Page 69: välkända astronomiska objekt  välkända typer av astronomiska objekt
Page 69: både vår och andra  både vår egen och andra
Paper I, page 26, column 2, paragraph 1: higher angular size distance  higher light travel time distance
Paper V, page 8: Division line should not be dashed