Near IR Emission from SupernovaRemnants
John Raymond
Rho et al.IC 443JHK
Why do J and H come froma completely different regionthan K?
Supernova Remnants
X-rays
T > 106 KUntil tcool
~ 15,000 yrs
H I lines(faint)
Supernova Remnants
X-rays
Optical, IR
Ram pressure= ρV2 = const
Vs < 200 km/s
Shock Waves
Convert Supersonic Motion to Subsonic (Frame of Shock)
Compress and slow gas;Convert Kinetic Energy Thermal Energy
T = 1.4x105 V1002 for ionized gas
n1 = 4 n0, v1 = v0 / 4 (relative to shock front)
Gas cools, becomes denser and slows down (relative to shock front)
n 1/T, but Magnetic Field may stop compression
Cool gas photoionized by radiation from upstream
Ionization, Balmer Line Filament (JJ Lee)
Nonradiative Region
Cooling Region
Photoionized Region
Radiative Shock Wave ( J-Shock)
[Fe II]
H I lines
Post-shock Density
J-Shock
Blair et al.
Strong Forbidden Lines; [Fe II] in Near IR
Strong UV and Ionizing Radiation if V > 80 km/s
Can produce weak H2 after cooling; Low T
20 km/s J-shock
Shock heats andcompresses gas
Produces Ly
Molecules formwhen gas coolsbelow 100 K
Bergin et al.Log time (yrs)
C-Shock
Jimenez-Serra et al.
Molecular gas, low ionization
Ions coupled to B fielddrift through neutrals
Ion-neutral friction heats thegas.
H2 excitation cools it.
T cannot exceed ~3000 KWithout destroying H2
Most of shock energy isConverted to H2 IR lines
Requires low ionized fraction
J-shock with Magnetic Precursor
Flower et al.
When heating rate becomestoo large or when H2 is destroyed,a J-shock forms.
Resulting spectrum is a mixtureof J- and C- shocks, [Fe II] andH2.
This does not work if V is largeenough to make ionizing photons.
H2 Boltzmann Diagram
Gredel
I(i,j) = N(j) Aji
Relative populations of levels give temperature; exp(-E/kT)
C-shock gives T ~ 2500 K
Multi-Temperature Case
Need Mid-IR rotationallines
Can indicate precursoror other excitationmechanism
Fluorescence
Cabrit et al.
Fluorescence by Ly
Mira; Karovska et al.HH 47; Curiel et al.
Multiple H2 Temperatures
Flower et al., HH 43
Slopes of log(N) vs Energy
[Fe II] from J-Shocks, H2 from C-Shocks
Oliva et al.; RCW 103
H2 filaments close to, but “ahead” of [Fe II] filaments
VERY different H2 and [Fe II] Line Widths
Oliva et al.; RCW 103
H2 line is unresolved at 130 km/s (Fabry-Perot)[Fe II] hundreds of km/s wideC-Shocks and precursors < ~ 50 km/s
Why H and K are disjoint
Oliva et al.
Another Example: Bullets in Orion Nebula
[Fe II] (green) from stronger shocksH2 (red) from weaker oblique shocks
AAT Image
High Resolution Spectra
S. ParkN49
High Resolution Spectra
VancuraN49
Long-slitEchelle
LMC Supernova Remnant N49 Long-slit Echelle
ShockedGas
Pre-shockPhotoionizedGas
Near IR High Resolution: H2
H2 Line profiles C-shock vs J-shock C-shock intrinsically narrow (T < 3000 K), but shock curvature increases line width Study interaction of blastwave with cloud Dominates cooling, luminosity, evolution
H2 Intensities T to discriminate C-shock, J-shock, Fluorescence, Formation
HH Objects
HH 47A
Position-Velocitydiagram; H2
Use with BowShock modelsto find shock parametersand flow
Correia et al.
Schwartz & Greene
Near IR High Resolution: [Fe II]
[Fe II] Intensities T, ne
[Fe II] profiles shock vs. precursor velocity and curvature of shock post-shock turbulence
Fe abundance?
Velocity ellipse for extragalactic SNRs
Summary
High resolution spectra of SNRs and HH Objects in H and K bands should mostly show H2 and [Fe II].
They generally come from different regions.
They can be used to determine shock parametersand to study the interaction of the shock withdense clouds.
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