Modeling the Radiation from the Supernova Remnant of SN1006

1
Modeling the Radiation from the Supernova Remnant
of SN1006

• Presenter Paul Edmon
• Preliminary Oral Exam
• Advisor Tom Jones
• 9-06-06

2
Overview

• Background
• Cosmicp
• SNR Model
• Results and Discussion

3
Supernovae

• Types
• SNIa
• WD explosion
• Can occur anywhere
• SNII
• Core Collapse
• Tend to occur in star-forming regions

Courtesy of the High-Z Supernova Search Team
4
Supernova Remnants

• Stages
• Free Expansion (200 yrs)
• Shock Velocity is roughly constant 10,000 km/s
• Ends when mass swept up equals mass ejected
• Sedov-Taylor (30,000 yrs)
• Shock Velocity goes as t-3/5
• Ends when the Post Shock Temperature drops to
  106 K
• Radiative (1,000,000 yrs)
• Shock Velocity goes as t-3/4
• Ends when the Shock Velocity is equal to the
  velocity dispersion of ISM

Courtesy of O. Krause
5
Supernova Remnants

• Importance
• Source of Heavy Elements and Mixing
• Large quantities of Fe, C, O and other heavy
  elements seen
• Source of Energy
• Total Energy 1051ergs
• Source of High Energy Cosmic Rays?

Courtesy of R. Sankrit W. Blair
6
Cosmic Rays

• Consist of
• Protons
• Nuclei
• Electrons
• Spectral Features
• Knee (1015eV)
• Ankle (1018eV)
• GZK cutoff (1019eV)

7
Diffusive Shock Acceleration (DSA)

• Model
• A thermal population of protons enter the shock
• Protons from the high energy tail diffuse through
  the shock scattering off of Alfvén waves
• Maximum possible accelerated energy is limited by
  the physical extent of the system and gyroradius
  of the proton

u1
u2
8
Diffusive Shock Acceleration (DSA)

• Good things
• Naturally takes a low energy proton population
  and turns it into a high energy population
• DSA gives the correct spectral slope for the CR
  spectrum
• If used in conjunction with SNRs it can explain
  the CR spectrum
• SNRs have enough energy to explain the CR
  spectrum
• SNRs have the correct spatial extent to explain
  the CR spectrum
• rg3.6pc for a proton at 1016eV and B3µG
• Bad things
• No good model for electron injection
• No current observational signature that protons
  are accelerated in SNRs

9
Confirming the Model by SNR

• DSA Model used is by Kang Jones (2006)
• CRASH (Cosmic-Ray Amr SHock)
• AMR shock code for Quasi-Parallel Shocks
• Flexible momentum binning
• Uses Sedov-Taylor similarity solutions for
  initialization
• Uses Bohm-like diffusion and is spherically
  symmetric
• Radiation Production Code (Cosmicp) was built in
  house
• Model applied to SN1006 (to be discussed later)

10
Cosmicp Overview

• Purpose To take an arbitrary charged particle
  spectrum in an arbitrary medium and produce the
  radiation and energy losses due to interactions
  with the medium.
• Inputs
• Initial Particle Spectra
• Magnetic Field
• Ambient Densities
• Ambient Photon Field
• Outputs
• Energy Losses
• Radiation
• Secondary Particles

11
Cosmicp Overview

• FORTRAN program in CGS units
• Processes Included
• Synchrotron
• Inverse Compton
• Bremsstrahlung
• Photopair Production
• Photopion Production
• Proton-Proton Interactions
• Photodisintegration
• Catastrophic Losses
• Knock-on Electrons
• Coulomb and Ionization Losses
• Decay Processes

12
Synchrotron, ICE, and Bremsstrahlung

• Synchrotron
• Plasma Frequency Suppression
• Inverse Compton Emission (ICE)
• Arbitrary Photon Field
• Bremsstrahlung

13
Photopair and Photopion Production

• Photopair Production
• N ? ? N e- e
• Expect At threshold (?109) lifetime is
  1.8x1010 yrs
• Photopion Production
• Reactions
• ? p ? p0 p
• ? p ? p n
• ? p ? p p- p
• Reaction Probabilities
• p0 42
• p 46
• p- 12
• Cross-section (Begelman et.al. (1990))
• Does not distinguish between pion types
• Approx 50 p0, 50 p

14
Proton-Proton Interactions

• Reactions Included
• p p ? p p p0
• p p ? p n p
• p p ? d p
• p p ? p p p p-
• Correction can be included for normal CR
  composition and normal ISM composition

15
Photodisintegration and Catastrophic Losses

• Photodisintegration
• Breaks apart nuclei into lower mass nuclei
• Has a lower threshold energy than Photopion
  Production
• Photodisintegration 10 MeV in the nucleus rest
  frame
• Photopion Production 145 MeV in the nucleus
  rest frame
• Catastrophic Losses
• Spallation and spallation products
• Not dealt with in program but rather particles
  are subtracted from spectra to account for this

16
Knock-on Electrons, Coulomb and Ionization Losses

• Knock-on Electrons
• CR brushes by atom ionizing it
• Coulomb Losses
• Losses due to CR momentum sharing with medium
• Ionization Losses
• Losses due to CR ionizing the medium
• All of these only important at low energies

17
Decays

• Decay Modes
• n ? p e- ?e
• p0 ? 2?
• p ? µ ?µ
• µ ? e ?µ ?e
• p- ? µ- ?µ
• µ- ? e- ?e ?µ
• Pions and muons decay automatically in the
  program due to their short lifetimes, Neutrons
  decay partially scaling with their Lorentz factor

18
Cosmicp Test GZK

• Greisen-Zatsepin-Kuzmin cutoff (Greisen (1966),
  Zatsepin Kuzmin (1966))
• Loss mechanism off of the CMB involving Photopair
  and Photopion production
• Limits the range that UHECR can travel and what
  can produce them

19
Cosmicp Test Galactic Spectrum

• Initial Conditions (Coronal and Intercloud ISM)
  (Schlickeiser (2002))
• B 2µG
• Te 105 K
• ne 10-3 cm-3
• nH .5 cm-3
• nHe .2 cm-3
• 4 Part Blackbody Spectrum for Ambient Photon
  Field (Schlickeiser (2002))
• B Stars
• K-G Stars
• Dust
• CMB
• j (ergs/cm3/s/octave) ? u (ergs/cm3/octave)
  conversion requires a characteristic time, in
  this case 25,000 years
• Known values for Galactic Radio Field (Salter
  Brown (1988))
• u(1 MHz)9.98x10-20 ergs/cm3/octave
• u(10 MHz)3.33x10-19 ergs/cm3/octave

20
Cosmicp Test Galactic Spectrum
Initial
Synchrotron
ICE
Bremsstrahlung
p0 Decay
21
Cosmicp Test Galactic Losses
Plasma
Plasma
Photopair
Synchrotron
Ionization
Bremsstrahlung
ICE
Proton-Proton
Photopion
22
Cosmicp Wrap-up

• Covers the important energy losses and radiation
  processes for CRs
• Arbitrary inputs for most variables
• All tested components are with 10 of their
  expected values, most are within 1
• Most errors can be reduced by increasing spectral
  resolution
• Processes not included in Cosmicp
• Triple Pair Production
• Line Emission

23
So where were we?

• Use the CRASH code in conjunction with Cosmicp to
  simulate the radiation from SN1006

24
SN1006

• Went off in AD 1006
• G.326.614.6
• D2.2kpc
• z555pc
• R6.8kpc
• R10pc
• Vs2800 km/s
• SNIa
• Mej1.4M?
• Winkler et.al. (2003)

Courtesy of J. Hughes et.al.
25
Model for SN1006

• Age 1000 yrs
• Radius 10pc
• nHne
• Case A .05 cm-3
• Case B .1 cm-3
• Dwarkadas Chevalier (1998)
• B 30 µG (suggested by Ksenofontov et.al.
  (2005))
• Explosion Energy
• Case A 1.9x1051 ergs
• Case B 2.8x1051 ergs
• Initialized in Sedov-Taylor Phase

26
Model for SN1006

• Electron-Proton Ratio 1100
• Electron Spectrum is extrapolated from the Proton
  Spectrum
• Low Energy Cutoff p lt .265mpc
• High Energy Electron Cutoff
• Case A 7.35 ergs/4.5 TeV
• Case B 6.46 ergs/4.0 TeV
• 4 Part Ambient Photon Field rescaled for the
  location in the galaxy (Model taken from Bloemen
  (1985))

27
Results

• Total Luminosity
• Case A 1.68x1036 ergs/sec
• Case B 5.2x1036 ergs/sec
• Total Volume 4.23x1060 cm3
• Proton Energy Turn Over 1.9x1016 eV

28
Results Particle Spectra
29
Results Photon Spectra
ICE
Synchrotron
p0 Decay
Bremsstrahlung
30
Results Photon Spectra
ICE
Synchrotron
p0 Decay
Bremsstrahlung
31
Magnetic Field

• High compared to normal ISM field of 3µG
• However it does match the data
• Upping the electron injection and using the
  normal ISM field still does not match the data
• CR Streaming Instability (Bell Lucek 2001)
• Has not been tested in nonideal MHD
• Has not been confirmed observationally
• Mechanism is needed though to enhance the
  magnetic field
• Research is being done into this area

32
Conclusions

• CRASH and Cosmicp can match SN1006 however a high
  magnetic field is required
• A pion production bump maybe visible around 400
  MeV
• A more detailed model of SN1006 including
  electron injection, acceleration and losses and
  geometric effects is warranted

33
Future Work

• A more complete model of SN1006
• A model for RX J1713.7-3946
• Seen in TeV gamma rays by HESS
• SNII into a WBB inside of a molecular cloud of n
  300 cm-3
• Turns out to be a very complicated problem
  because the shock stalls at the WBB
• Applying Cosmicp to other simulations (Jet,
  Cosmological, etc.)

Courtesy of the HESS Collaboration
34
Acknowledgements

• Tom Jones
• Hyesung Kang
• Sean ONeill
• Reinhard Schlickeiser
• Minnesota Space Grant and NASA
• University of Minnesota Astronomy Department
• Minnesota Supercomputing Institute
• And all of you for sitting through this!

35
Results Particle Phase Space
Case A
Case B
logp
logp
Radius
Radius
36
Results Photon Phase Space
Case A
Case B
log?
log?
Radius
Radius
37
Photon Phase Space Breakdown
Synchrotron
ICE
log?
log?
Radius
Radius
38
Photon Phase Space Breakdown
Bremsstrahlung
p0 Decay
log?
log?
Radius
Radius
Back
39
Photon Phase Space Breakdown
Synchrotron
ICE
log?
log?
Radius
Radius
40
Photon Phase Space Breakdown
p0 Decay
Bremsstrahlung
log?
log?
Radius
Radius
Back
41
Synchrotron Spectrum Test
42
ICE Tests
43
Bremsstrahlung Tests
44
Knock-on Test
45
Coulomb and Ionization Tests
46
Photopair Production Spectrum