Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus,...
-
date post
22-Dec-2015 -
Category
Documents
-
view
215 -
download
1
Transcript of Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus,...
![Page 1: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/1.jpg)
Type Ia Supernovae on a glass:The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007
Troels Haugbø[email protected]
Institute for Physics & Astronomy, Århus University
Collaborators:Steen Hannestad, Bjarne Thomsen
![Page 2: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/2.jpg)
Goals of our project
● Predict how well we can probe the local velocity field, with upcoming supernovae surveys
● Design the optimal observational strategy to maximize science output
● Understand how the angular power spectrum of the peculiar velocity field can be used as a tool for constraining cosmology
![Page 3: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/3.jpg)
Velocity Fields
● Velocity trace mass:● The peculiar velocity field is sourced by the gravitational
potential: It is directly dependent on the dark matter dist No bias!
● Further away than ~100 Mpc h-1 cosmic variance is small, and we can constrain cosmological models!The velocity field 30 Mpc away The density field 30 Mpc away
-560 960 km/s
![Page 4: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/4.jpg)
velocity contra density
● To measure the density we have to ● count standard objects● take care not to miss any!
● Density is derived from number counts. ● Then put in the conversion from
luminosity to mass, completeness, bias to dark matter etc
● The velocity field can be ● measured directly and sparsely ● Good, since there are few SnIa’s
● At large distances the Hubble Flow dominate
![Page 5: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/5.jpg)
How to measure vr
● Requisites:The redshift of the host galaxyThe distance or the apparent and absolute magnitudes
● Traditionally used methods to obtain the distance include● The Tully-Fisher relation● Surface brightness fluctuations● Fundamental plane● Reconstruction from the density field of redshift surveys
● They all have an intrinsic scatter of at least m=0.3-0.4
![Page 6: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/6.jpg)
How to measure vr
● Requisites:The redshift of the host galaxyThe distance or the apparent and absolute magnitudes
● Traditionally used methods to obtain the distance include● The Tully-Fisher relation● Surface brightness fluctuations● Fundamental plane● Reconstruction from the density field of redshift surveys
● They all have an intrinsic scatter of at least m=0.3-0.4
● With upcoming surveys Type Ia Supernovae will have an intrinsic scatter of m=0.08-0.1
![Page 7: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/7.jpg)
Upcoming surveys● The change in apparent magnitude with redshift is used to
constrain the cosmology. Many surveys will be done the next couple of years.
(Hui & Greene a-ph/0512159)
![Page 8: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/8.jpg)
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Upcoming surveys● Unfortunately surveys have small FOV, and are designed for
high redshift SNe. In fact weak lensing/asteroid surveys are better for local supernovae. They scan the sky continuously, and observe in many bands (typically 6)
Pan-Starrs Sky Mapper
4x1.4Gp
2007
256Mp
2008
Hawaii Australia
LSST3.2Gp
2013
Chile
![Page 9: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/9.jpg)
Forecast● We know the local supernova rate
● This gives 60000 Type Ia SN per year inside a distance of 500 h-1 Mpc
Typically peculiar velocities are ~ 400 km s-1
● We want to look at the angular distribution as a function of distance. Binning in a reasonable manner we have
1100 SnIa at 60 h-1Mpc with error vr ~ 220 km s-1
7000 SnIa at 150 h-1Mpc with error vr ~ 550 km s-1
35000 SnIa at 350 h-1Mpc with error vr ~ 1300 km s-1
![Page 10: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/10.jpg)
Forecast● We know the local supernova rate
● This gives 60000 Type Ia SN per year inside a distance of 500 h-1 Mpc
● There are light curves, but we need precise redshifts● Low redshift Type Ia Supernovae are not a priority
● We need to do it ourselves● It is not realistic to measure 60000 redshifts per year.
![Page 11: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/11.jpg)
How to make a supernova survey
Make Nbody sim
Find density and velocity on a spherical shell
Populate with Supernovae
Calculate Power spectrum
![Page 12: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/12.jpg)
...but there is more to it
● With a limited amount of SNe, we can only measure a limited part of the powerspectrum
● Algorithm:● Given a set of Supernovae. Calculate powerspectrum
![Page 13: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/13.jpg)
...but there is more to it
● With a limited amount of SNe, we can only measure a limited part of the powerspectrum
● Algorithm:● Given a set of Supernovae. Calculate powerspectrum● Make N mock catalogues with same errors
![Page 14: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/14.jpg)
...but there is more to it
● With a limited amount of SNe, we can only measure a limited part of the powerspectrum
● Algorithm:● Given a set of Supernovae. Calculate powerspectrum● Make N mock catalogues with same errors● Compare the mock powerspectra to the underlying
powerspectrum● This gives the error term
![Page 15: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/15.jpg)
...but there is more to it
● With a limited amount of SNe, we can only measure a limited part of the powerspectrum
● Algorithm:● Given a set of Supernovae. Calculate powerspectrum● Make N mock catalogues with same errors● Compare the mock powerspectra to the underlying
powerspectrum● This gives the error term
● Subtract the error term from the observed powerspectrum
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
![Page 16: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/16.jpg)
Supernovae on a glass
● We know the local supernova rate
● This gives 60000 Type Ia SN per year inside a distance of 500 h-1 Mpc
● There are light curves, but we need precise redshifts● Low redshift Type Ia Supernovae are not a priority
● We need to do it ourselves● It is not realistic to measure 60000 redshifts per year.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
![Page 17: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/17.jpg)
Goals of our project
● Predict how well we can probe the local velocity field, with upcoming supernovae surveys
● Design the optimal observational strategy to maximize science output
● Understand how the angular power spectrum of the peculiar velocity field can be used as tool for constraining cosmology
![Page 18: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/18.jpg)
Connecting the matter and velocity powerspectrum
● Velocity trace mass:● The angular velocity powerspectrum is related to
the matter powerspectrum:
● Which can be simplified to:
![Page 19: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/19.jpg)
Connecting the matter and velocity powerspectrum
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
● We can find the average amplitude between
l=5-20● It is free of cosmic variance
![Page 20: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/20.jpg)
Consequences for cosmology● The overall amplitude depends on
This combination break
degeneracies,and8 can be constrained
● The form of the velocity powerspectrum is directly related to the shape parameter
● The amplitude and shape at l=5-20 is not affected much by cosmic variance
● Success depends on proper observational strategy - can I have a glass, please?
![Page 21: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/21.jpg)
Other factors apply to the lumi-nosity distance at high redshift
(Sugiura et al ‘99,Hui & Greene a-ph/0512159, Bonvin et al a-ph/0511183)
Light travels along geodesics, and is influenced by:
● The peculiar motion of the source and the observer, giving rise to a redshift.
● Gravitational lensing. It (de)magnifies the light rays and depends on the fluctuations in the gravitational potential● Gravitational redshift
● An integrated effect from line-of-sight change in the potential (Sachs-Wolfe effect)
![Page 22: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/22.jpg)
Other factors apply to the lumi-nosity distance at high redshift
(Sugiura et al ‘99,Hui & Greene a-ph/0512159, Bonvin et al a-ph/0511183)
Light travels along geodesics, and is influenced by:
● The peculiar motion of the source and the observer, giving rise to a redshift.
● Gravitational lensing. It (de)magnifies the light rays and depends on the fluctuations in the gravitational potential● Gravitational redshift
● An integrated effect from line-of-sight change in the potential (Sachs-Wolfe effect)
Important at low redshift
Important at high redshift
![Page 23: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/23.jpg)
Are we living in a Hubble Bubble?(Zehavi et al a-ph/9802252)
● Used 44 SnIa● H= vr / dL
● Model suggest we are in an underdense region with radius of 70 Mpc h-1
![Page 24: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/24.jpg)
Can we trust the local Hubble parameter?
(Shi a-ph/9707101,Shi MNRAS, 98 )
● Used 20 SnIa (Upper plot) and 36 clusters with T-F relation
● Make CDM models that mimick the local density fields
● Run different cosmological scenarioes
● Compare! It is hard to see the difference, with current data.
● There is a 2% error on H0 out to about 250 Mpc h-1
![Page 25: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/25.jpg)
How big is the dipole?(Bonvin et al a-ph/0603240)
● Use the same 44 SnIa● As a test, given H0, measure the
CMB dipole● Gives 405±192 km/s
![Page 26: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/26.jpg)
How big is the dipole?(Bonvin et al a-ph/0603240)
● Use the same 44 SnIa● As a test, given H0, measure the
CMB dipole● In the future: Given the CMB dipole
amplitude |v0|, measure H(z)● 100’s of SnIa’s needed for 30% error
![Page 27: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/27.jpg)
The lowest multipoles and the local universe
● The lowest multipoles of the angular powerspectrum are easy to understand
● The monopole gives the contraction/expansion
● The dipole measures average flow
● The quadrupole represents the first shear mode
![Page 28: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/28.jpg)
The peculiar velocity at higher redshifts and the cosmic web
Timeline in movie
To give a feeling for the cosmic large scale structure I will show you two movies, where we slowly zoom out and see structure further and further away
Distance to the observer
![Page 29: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/29.jpg)
The peculiar velocity at higher redshifts and the cosmic web
QuickTime™ and aBMP decompressor
are needed to see this picture.
![Page 30: Type Ia Supernovae on a glass: The bread and butter of peculiar velocities Lunch meeting Aarhus, March 2007 Troels Haugbølle haugboel@phys.au.dk Institute.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d7f5503460f94a63770/html5/thumbnails/30.jpg)
The angular powerspectrum
Size of voids
Size of clusters