Quasars and Low Surface Quasars and Low Surface Brightness Galaxies as Brightness Galaxies as Probes of Dark MatterProbes of Dark Matter

Erik ZackrissonErik Zackrisson

OutlineOutline Dark matterDark matter

Dark matter halosDark matter halos Baryonic and non-baryonic dark matterBaryonic and non-baryonic dark matter Cold dark matterCold dark matter

QuasarsQuasars Gravitational lensingGravitational lensing RedshiftRedshift

Low Surface Brightness GalaxiesLow Surface Brightness Galaxies Rotation curvesRotation curves

Summary of ResultsSummary of Results

Dark matter Luminous matter

Dark MatterDark Matter

First detection of dark matterFirst detection of dark matter

Fritz Zwicky (1933): Dark matter in the Coma ClusterFritz Zwicky (1933): Dark matter in the Coma Cluster

The Dark Matter ProblemThe Dark Matter Problem

~2%(Luminous)

~98% (Dark)

Dark Matter Halos IDark Matter Halos I

Galaxy Stars + Gas + Dust + Supermassive Black Hole + Dark Matter

Dark Matter Halos IIDark Matter Halos II

Luminous galaxy

Dark halo

Baryonic & Non-Baryonic Baryonic & Non-Baryonic Dark MatterDark Matter

Baryonic matter: ~15%Baryonic matter: ~15%Example: Stars, gas clouds, planets…Example: Stars, gas clouds, planets…Missing: ~ 35%Missing: ~ 35%

Non-baryonic matter: ~85%Non-baryonic matter: ~85% Example: Axions, neutralinos,Example: Axions, neutralinos, primordial black holes…primordial black holes…Missing: ~ 100%Missing: ~ 100%Best model: Cold Dark Matter (CDM)Best model: Cold Dark Matter (CDM)

Cold dark matter and Cold dark matter and the evolution of structurethe evolution of structure

Cold dark matter and Cold dark matter and the evolution of structure IIthe evolution of structure II

Cold Dark Matter HalosCold Dark Matter Halos

R

RDark matter halo

Den

sity

Central densitycusp predicted bycold dark matter

Observed

QuasarsQuasars

Gravitational lensingGravitational lensing

Gravitational lensing IIGravitational lensing II

Microlensing Made SimpleMicrolensing Made Simple

Obs! Fel bild!

Microlensing Made Simple IIMicrolensing Made Simple II

Claim: The long-term optical variability Claim: The long-term optical variability of quasars is quased by microlensingof quasars is quased by microlensing

Hawkins, M.R.S. (1993, 1996, 1997, 2000, 2001, 2002, 2003)

The dark matter puzzle solved?The dark matter puzzle solved?

Mcompact 10-3 Msolar Almost all of the dark matter in this form Primordial black holes?

Expansion of the UniverseExpansion of the Universe

RedshiftsRedshifts

High z Large distanceLow z Small distance1

emit

obs z

Claims of non-cosmological Claims of non-cosmological redshiftsredshifts

Low-z galaxy surrounded by overdensity of high-z quasars

Low-z galaxy with pairs of high-z quasars (with z1z2)

aligned along minor axis

z1

z2

Ejection scenariosEjection scenarios

Local galaxy, very low redshift (z1)

Faint quasar, high redshift (>>z1)

Bright quasar, low redshift (>z1)

New galaxy (?), very low redshift (z1)?

?

?

?

?

Low Surface Brightness GalaxiesLow Surface Brightness Galaxies

The Very Large Telescope Examples ofTarget Galaxies

The Central Mass BudgetThe Central Mass BudgetLow Surface

Brightness GalaxiesHigh Surface

Brightness Galaxies

Dark matter

Luminous matter

Dark matter

Luminous matter

Rotation CurvesRotation Curves

Radius

Vrot

Radius

Density

Spectroscopy → Rotation Curve → Density Profile

CDM prediction

Observed

ResultsResultsPaper IPaper I Uncertainties in the typical quasar size Uncertainties in the typical quasar size Quasar Quasar

variability cannot easily be used to constrain dark matter variability cannot easily be used to constrain dark matter at the current time at the current time

Paper IIPaper II Microlensing cannot explain the long-term optical Microlensing cannot explain the long-term optical

variability of quasars – Hawkins is wrong!variability of quasars – Hawkins is wrong!

Paper IIIPaper III Non-cosmological redshift scenarios involving quasar Non-cosmological redshift scenarios involving quasar

ejection can be tested with observations of quasar host ejection can be tested with observations of quasar host galaxies made a small telescopegalaxies made a small telescope

Results IIResults IIPaper IVPaper IV The bluest low surface brightness galaxies can be used The bluest low surface brightness galaxies can be used

to test hierarchical galaxy formation models – provided to test hierarchical galaxy formation models – provided that we can derive their agesthat we can derive their ages

The star formation rate of the bluest low surface The star formation rate of the bluest low surface brightness galaxies cannot have been constant or brightness galaxies cannot have been constant or increasing – unless the stellar initial mass function is increasing – unless the stellar initial mass function is unusual unusual

Paper VPaper V The density profiles of the dark halos surrounding the The density profiles of the dark halos surrounding the

bluest low surface brightness galaxies are in conflict with bluest low surface brightness galaxies are in conflict with the Cold Dark Matter predictionsthe Cold Dark Matter predictions

ErrataErrata Spikblad: Polhemssalen Spikblad: Polhemssalen Polhemsalen Polhemsalen Page v: optical long-term Page v: optical long-term long-term optical long-term optical Page 3: as the ray crossed Page 3: as the ray crossed as its ray grazed as its ray grazed Page 24 (twice): reflectance Page 24 (twice): reflectance reflection reflection Page 33: z Page 33: z 2—3 2—3 z z 2—4 2—4 Page 35: the latter variations Page 35: the latter variations these variations these variations Page 35: hoever are Page 35: hoever are are however are however Page 37: by fast rise Page 37: by fast rise by a fast rise by a fast rise Page 44: 10Page 44: 101212—10—101414 m m 10 101212—3—310101313 m m Page 56: disk by Page 56: disk by disk is given by disk is given by Page 69: ett par procent Page 69: ett par procent några få procent några få procent Page 69: välkända astronomiska objekt Page 69: välkända astronomiska objekt välkända typer av välkända typer av

astronomiska objekt astronomiska objekt Page 69: både vår och andra Page 69: både vår och andra både vår egen och andra både vår egen och andra Paper I, page 26, column 2, paragraph 1: higher angular size Paper I, page 26, column 2, paragraph 1: higher angular size

distance distance higher light travel time distance higher light travel time distance Paper V, page 8: Division line should not be dashed Paper V, page 8: Division line should not be dashed