Summary of this work p We study the hydrogen line emission from SNR - - PowerPoint PPT Presentation
On On modeling of hydrogen line emission fr from supernova remnant shocks: the effect of of Lyman an line trap apping
Supernova Remnants (SNRs) Pulsar Wind Nebulae
Winkler+14 Smith 97 Figures from Morlino+15
Supernova Remnants (SNRs)
Winkler+14 Smith 97
applicable to other
Spectrum of Balmer line Emissions (Ghavamian+02, for SNR SN 1006) The lines consist of “narrow” and ”broad” components.
narrow broad
p e
upstream downstream SNR!shock!
Hydrogen atoms → no dissipation
formed by the interaction between charged particles and plasma waves rather than Coulomb collision.
hydrogen atoms) are not affected.
H + p (or e) → H* + p (or e) H + p → p + H*
p Collisional Excitation p Charge Transfer
Emits “narrow” comp. Emits “broad” comp.
p e
upstream downstream SNR!shock!
Hydrogen atoms → no dissipation
H + p (or e) → H* + p (or e) H + p → p + H*
p Collisional Excitation p Charge Transfer
Emits “narrow” comp. Emits “broad” comp.
p e
upstream downstream SNR!shock!
Hydrogen atoms → no dissipation
SNR Shock velocity Narrow component (km s−1) FWHM (km s−1) Cygnus Loop 300−400 28−35 RCW 86 SW 580−660 32 ± 2 RCW 86 W 580−660 32 ± 5 RCW 86 NW 580−660 40 ± 2 Kepler D49 & D50 2000−2500 42 ± 3 0505-67.9 440−880 32−43 0548-70.4 700−950 32−58 0519-69.0 1100−1500 39−42 0509-67.5 − 25−31 Tycho 1940−2300 44 ± 4 SN 1006 2890 ± 100 21 ± 3
Sollerman+2003 ü The width of narrow component is in the 30-50 km/s range (equivalently, 2.5-5.6 eV). ü If these were the ISM equilibrium temperatures, then all of hydrogen atoms would be completely ionized! 1 eV ←→ 21 km/s
SNR Shock velocity Narrow component (km s−1) FWHM (km s−1) Cygnus Loop 300−400 28−35 RCW 86 SW 580−660 32 ± 2 RCW 86 W 580−660 32 ± 5 RCW 86 NW 580−660 40 ± 2 Kepler D49 & D50 2000−2500 42 ± 3 0505-67.9 440−880 32−43 0548-70.4 700−950 32−58 0519-69.0 1100−1500 39−42 0509-67.5 − 25−31 Tycho 1940−2300 44 ± 4 SN 1006 2890 ± 100 21 ± 3
Sollerman+2003 ü The width of narrow component is in the 30-50 km/s range (equivalently, 2.5-5.6 eV). ü If this were the ISM equilibrium temperature, then all
would be completely ionized!
1 eV ←→ 21 km/s
p e
upstream downstream SNR!shock!
Hydrogen atoms → no dissipation
H + p → p + H*
p Charge Transfer ü A part of downstream hydrogen atoms can be back to the upstream region (e.g. Smith+94). ü The leaking hydrogen can deposit some energy flux to the upstream fluid via several atomic/plasma processes.
p e
upstream downstream SNR!shock!
Hydrogen atoms → no dissipation
H + p/e → p + e + p/e
p Ionization of fast neutrals
H + p → p + H*
p Charge Transfer heat up
Emits the anomalous narrow component with the width of 30-50 km/s
p e
upstream downstream SNR!shock!
Hydrogen atoms → no dissipation
H + p/e → p + e + p/e
p Ionization of fast neutrals
H + p → p + H*
p Charge Transfer heat up
Emits the anomalous narrow component with the width of 30-50 km/s
p e
upstream downstream SNR!shock!
Hydrogen atoms → no dissipation
CRs The CRs accelerating via DSA mechanism can also affect the upstream plasma (or can generate Alfvenic turbulence in the upstream region). The formation of the anomalous narrow component is similar to the neutral precursor case. heat up
p e
upstream downstream SNR!shock!
Hydrogen atoms → no dissipation
CRs The CRs accelerating via DSA mechanism can also affect the upstream plasma (or can generate Alfvenic turbulence in the upstream region). The formation of the anomalous narrow component is similar to the neutral precursor case. heat up
10-2 10-1 100
50 100 Hα emissivity vx [km/s] Vsh= 4000 km/s n0 = 0.1 cm-3 pmax = 50 TeV/c no CR ξinj= 3.5; ηTH= 0.0 0.2 0.5 0.8
The semi-analytical model predicts the anomalous narrow component arising from the CR precursor (Morlino+13).
20 20 25 30 35 40 45 50 55 60 5 10 15 20 25 30 35 40 45 50 pmax [TeV/c] ηTH= 0.8
Maximum Energy of CRs [TeV/c] FWHM of narrow [km/s]
FWHM of the narrow component depends on the Maximum energy of CRs (Morlino+13).
20 20 25 30 35 40 45 50 55 60 5 10 15 20 25 30 35 40 45 50 pmax [TeV/c] ηTH= 0.8
Maximum Energy of CRs [TeV/c] FWHM of narrow [km/s]
FWHM of the narrow component depends on the Maximum energy of CRs (Morlino+13).
Lyb absorbed reemitted Ha Ha 3p → 2s Ha is not absorbed by the hydrogen atoms in ground state. Lyb 3p → 1s a) A part of hydrogen atoms in n=3 emit Lyb due to 3p to 1s transition. b) The emitted Lyb is is ab absorbed by the hydrogen atoms in in ground state. c) Ev Eventually, Lyb is is converted to Ha due due to 3p p to 2s trans nsition.
Lyb absorbed reemitted Ha Ha 3p → 2s Ha is not absorbed by the hydrogen atoms in ground state. Lyb 3p → 1s
p The number density of “2s” hydrogen atoms:
A2s,1s ≈ 8.2 s−1
p Optical thickness of the Ha photons:
Spontaneous transition rate:
≈ C1s,2s ∼ 10−7-10−6 s−1
nH(2s) nH(1s)C1s,2s A2s,1s ∼ 10−8-10−7 × nH(1s)
∼ τ ∼ σνnH(2s)L 0.1
10−7 cm−3 L 1018 cm
p The number density of “2s” hydrogen atoms:
A2s,1s ≈ 8.2 s−1
p Optical thickness of the Ha photons:
Spontaneous transition rate:
≈ C1s,2s ∼ 10−7-10−6 s−1
nH(2s) nH(1s)C1s,2s A2s,1s ∼ 10−8-10−7 × nH(1s)
∼ τ ∼ σνnH(2s)L 0.1
10−7 cm−3 L 1018 cm
Narrow line for Optically thin case Narrow line for Optically thick case
Efficient absorption around the line center Modest absorption far from the line center
Narrow line for Optically thin case Narrow line for Optically thick case
Efficient absorption around the line center Modest absorption far from the line center
Narrow line for Optically thin case Narrow line for Optically thick case
Efficient absorption around the line center Modest absorption far from the line center
: the number density of hydrogen atom at the state k
[nH(k) (Pk,j + Ck,j) − nH(j) (Pj,k + Cj,k)] = 0,
: the collisional rate for k to j
Here, we only consider the collisional rate from 1s because the mean collision time is very longer than the radiative decay time.
Pk,j = Ak,j + gj gk 4πσν hν Jνdν, Pj,k = 4πσν hν Jνdν,
Jν = 1 4π
In order to evaluate the radiative rate, we need to calculate the mean intensity Jn , that is, the specific intensity In .
pAs the first step, we consider the radiative line transfer and the atomic population problem for the plane parallel shock.
x
Shock (x = 0) upstream downstream Outer boundary Inner boundary
z
1016 cm 5x1016 cm Fully ionized
pAs the first step, we consider the radiative line transfer and the atomic population problem for the plane parallel shock.
x
Shock (x = 0) upstream downstream Outer boundary Inner boundary
z
1016 cm 5x1016 cm Fully ionized
upstream: shifted Maxwellian with temperature T0 = 1 eV and bulk velocity Vsh ≈ 2000 km/s with assuming the temperature equilibrium.
fH,0(vH) = nH,0 mH 2πkT0 3/2 exp
2kT0
= np,0 mp 2πkT0 3/2 exp
2kT0
= ne,0
2πkT0 3/2 exp
2kT0
downstream:
fH,2(vH) = nH,0ξn mH 2πkT0 3/2 exp
2kT0
nH,0ξb
2πkTp,2 3/2 exp
2kTp,2
= np,2
2πkTp,2 3/2 exp
2kTp,2
= ne,2
2πkTe,2 3/2 exp
2kTe,2
SNR shell with radius 3pc z Observer adapt
Fully ionized
SNR shell z Observer adapt
0.2 0.4 0.6 0.8 1
20 40 Intensity [a.u.] hydrogen velocity [km s-1] 0.2 0.4 0.6 0.8 1
20 40 Intensity [a.u.] hydrogen velocity [km s-1]
Hb Ha
20 25 30 35 40 45 50 55 60 1 2 3 4 5 FWHM [km s-1] nH,0 [cm-3] Ha Hb
SNR Shock velocity Narrow component (km s−1) FWHM (km s−1) Cygnus Loop 300−400 28−35 RCW 86 SW 580−660 32 ± 2 RCW 86 W 580−660 32 ± 5 RCW 86 NW 580−660 40 ± 2 Kepler D49 & D50 2000−2500 42 ± 3 0505-67.9 440−880 32−43 0548-70.4 700−950 32−58 0519-69.0 1100−1500 39−42 0509-67.5 − 25−31 Tycho 1940−2300 44 ± 4 SN 1006 2890 ± 100 21 ± 3
20 25 30 35 40 45 50 55 60 1 2 3 4 5 FWHM [km s-1] nH,0 [cm-3] Ha Hb
The anomalous narrow component comes from the atomic processes without CR acceleration!