Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Theoretical SEDs in Starbursts: SFRs in both the UV and IR Brent Groves Max Planck Institute for Astrophysics Brent Groves Max Planck Institute for Astrophysics

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Made By Many Michael Dopita, Ralph Sutherland, Jörg Fischera (RSAA,ANU) Cristina Popescu, Richard Tuffs (MPIK) Lisa Kewley (IfA, Hawaii) Michiel Reuland (Leiden) & Claus Leitherer (STSCI) Michael Dopita, Ralph Sutherland, Jörg Fischera (RSAA,ANU) Cristina Popescu, Richard Tuffs (MPIK) Lisa Kewley (IfA, Hawaii) Michiel Reuland (Leiden) & Claus Leitherer (STSCI)

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Why Starbursts? Starburst Galaxies form many stars very quickly and hence: Can give insight into the Initial Mass Function (IMF) Are very bright and can be seen at the earliest epochs helping us understand galaxy formation Are dominated by the youngest and most massive stars and many other reasons... Starburst Galaxies form many stars very quickly and hence: Can give insight into the Initial Mass Function (IMF) Are very bright and can be seen at the earliest epochs helping us understand galaxy formation Are dominated by the youngest and most massive stars and many other reasons...

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Why Models? Understanding the Physics behind Starbursts Provide Pan Spectral Diagnostics to determine general parameters of Star-forming Galaxies Provide Self-consistent, Theoretical Star Formation Rate Measures at several Wavelengths Understanding the Physics behind Starbursts Provide Pan Spectral Diagnostics to determine general parameters of Star-forming Galaxies Provide Self-consistent, Theoretical Star Formation Rate Measures at several Wavelengths

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Star Formation Rates Can use any part of spectrum (eg. Hα, UV, IR) Best is a full Spectral Energy Distribution (SED) But must account for dust ∴ Need to calculate dust extinction and emission Can use any part of spectrum (eg. Hα, UV, IR) Best is a full Spectral Energy Distribution (SED) But must account for dust ∴ Need to calculate dust extinction and emission

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Heating Dust As the grains absorb the incident photons they heat up and emit thermal radiation For large grains, the absorption and emission reach an equilibrium state so that the grain has a steady temperature For small grains however things become stochastic... As the grains absorb the incident photons they heat up and emit thermal radiation For large grains, the absorption and emission reach an equilibrium state so that the grain has a steady temperature For small grains however things become stochastic...

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Hot & Cold Smallest grains have small cross-section hence low photon heating rate However, small grains also have low specific heat one photon causes large increase in Temperature Smallest grains have small cross-section hence low photon heating rate However, small grains also have low specific heat one photon causes large increase in Temperature

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Quick & Dirty Dust IR Solve for Grain Temperature Probability Distribution Convolve with Blackbody and integrate over dust sizes and types to get IR emission Include the emission from PAH Solve for Grain Temperature Probability Distribution Convolve with Blackbody and integrate over dust sizes and types to get IR emission Include the emission from PAH

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 From Star to Finish (SED) Use stellar synthesis code (STARBURST99) to generate stellar spectrum of different aged bursts Use radiative transfer code (MAPPINGS) to determine HII spectrum and hot dust extinction and emission Use MAPPINGS to determine PDR spectrum of warm dust & PAH extinction and emission Pass final spectrum through (diffuse, cold) dusty screen Use stellar synthesis code (STARBURST99) to generate stellar spectrum of different aged bursts Use radiative transfer code (MAPPINGS) to determine HII spectrum and hot dust extinction and emission Use MAPPINGS to determine PDR spectrum of warm dust & PAH extinction and emission Pass final spectrum through (diffuse, cold) dusty screen

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Making Stars The Stellar Emission Instantaneous bursts of 10 4 M ☉ sampled at intervals of 1 Myr up to 10 Myr Continuous at 1 M ☉ yr -1 up to 10 8 yrs for >10 Myr population The Stellar Emission Instantaneous bursts of 10 4 M ☉ sampled at intervals of 1 Myr up to 10 Myr Continuous at 1 M ☉ yr -1 up to 10 8 yrs for >10 Myr population

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Blown Away The HII Region All Stellar light passes through HII region Evaluated for 3 different Pressures: P/k=10 4, 10 6 and 10 7 cm -3 Includes dynamical evolution of Stellar wind bubble The HII Region All Stellar light passes through HII region Evaluated for 3 different Pressures: P/k=10 4, 10 6 and 10 7 cm -3 Includes dynamical evolution of Stellar wind bubble

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Hot & Bothered

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Clearing the Mess The Photodissociation Region Molecular cloud covers fraction of HII region Absorbs Far-UV and gives warm dust and PAH emission Explore clearing timescale (~covering fraction) of PDR clouds f(t)=exp(-t/τ clear ) τ clear =1, 2, 4, 8, 16 and 32 Myr The Photodissociation Region Molecular cloud covers fraction of HII region Absorbs Far-UV and gives warm dust and PAH emission Explore clearing timescale (~covering fraction) of PDR clouds f(t)=exp(-t/τ clear ) τ clear =1, 2, 4, 8, 16 and 32 Myr

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Adding PDRs

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Dusty Screen The dusty screen Provides attenuation by diffuse dust Does not include cold dust emission The dusty screen Provides attenuation by diffuse dust Does not include cold dust emission

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Under Pressure

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Seeing through...

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 A Fitting Example...

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 IRAS Diagnostics

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Spitzer Diagnostics

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Rating Star Formation The models then give the following relationships between SFR and standard indicators

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Rating Star Formation Star Formation Rates for τ clear =1 Myr and for τ clear =32 Myr and P/k=10 7 cm -3

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 SEDing The End While limited, these self-consistent theoretical starburst SEDs: Demonstrate that two parameters control the form of the SED Pressure in the diffuse ISM Molecular cloud clearing timescale Can reproduce observed starburst SEDs over 3 decades of frequency While limited, these self-consistent theoretical starburst SEDs: Demonstrate that two parameters control the form of the SED Pressure in the diffuse ISM Molecular cloud clearing timescale Can reproduce observed starburst SEDs over 3 decades of frequency

Recontres de Moriond XXV La Thuile, March 2005 Recontres de Moriond XXV La Thuile, March 2005 Pan-SED End These models also Explain the observed spread in observations on IRAS Colour-Colour Diagrams Predict possible diagnostics in Spitzer Diagnostic Diagrams Are a step forward in obtaining fully theoretical SFR indicators and explaining the links between different wavelength regimes These models also Explain the observed spread in observations on IRAS Colour-Colour Diagrams Predict possible diagnostics in Spitzer Diagnostic Diagrams Are a step forward in obtaining fully theoretical SFR indicators and explaining the links between different wavelength regimes