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.