C - MAGPOP

Controlling Parameters
of the Starburst SED
Brent Groves
(Leiden University)

And the Thanks go to...
• Mike Dopita (ANU)
• Jörg Fischera (CITA)
• Lisa Kewley (U. Hawai’i)
• Claus Leitherer(STScI)
• and many others...

The Ideal SB Galaxy
• Stars born in dense, cool
clouds - UCHII
• Over time winds & SN
expand bubble & clear
HI
• Old stars left in diffuse
ISM
• Through it all - dust!
*
*
*
*
*
* *
*
*
HII HI
*
*
*
*
*
*
*
ISM
HI HII
*
*
* *
*
*
*
*
*
*
*
Charlot & Fall 2000

The Mess that is a real SB Galaxy
• In reality, a galaxy is a
mess of young & old
stars and dust
• In Starbursts young stars
dominate the luminosity,
especially in mid- and
far-IR
• Geometry not as strong
an issue!
M82 -
local Starburst

log "F" (erg s -1)
model
• Starburst99 Stellar models (stellar spectra 0-10Myr)+
• MAPPINGSIII Photoionization code (HII and PDR Spectra)+
• Simple Stellar wind bubble evolution (RHII, PHII)
• Average over 0-10 Myrs to represent real burst (not
‘instantaneous’)
! (µm)
log "F" (erg s -1)
! (µm)

• IF P/k (Mcl) varies
and C constant,
overall SED the
same (though lines
different
C the effects!
log"F " (erg s -1)
43.0
42.0
41.0
log C = 5.0
4.0 # log[P/k] # 8.0
0.1 1.0
10.0 100.0
1000
! (µm)

• If P/k constant but C
varies, overall SED
C the effects!
log "F" (erg s-1)
43.5
43.0
42.5
42.0
41.5
41.0
! (µm)
log C
6.0
6.5
5.0
4.0

model-2
• Series of Starburst models with:
• Metallicity Z
• Compactness C
• Pressure P0/k (equally )
• fPDR (fraction PDR/HII)
• fUCHII (fraction 10 Myr, think b=SFR/)
• fdiffuse (measure diffuse IR emission, heated by diffuse UV)
• A(V) (external ‘screen’ extinction, related to fdiffuse)
• and scaling to Luminosity gives SFR!!!

Parameters vs. NGC 6240
• C parameter
log!F ! (erg s -1)
44.0
43.0
42.0
41.0
40.0
39.0
NGC6240: log C = 5.5, 6.0, 6.5
-1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
log " (µm)

Parameters vs. NGC 6240
• C parameter
• f(UCHII)
log!F ! (erg s -1)
44.0
43.0
42.0
41.0
40.0
39.0
NGC6240: F(UCHII) = 0.0, 0.15, 0.6
-1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
log " (µm)

Parameters vs. NGC 6240
• C parameter
• f(UCHII)
• f(old)
log!F ! (erg s -1)
44.0
43.0
42.0
41.0
40.0
39.0
NGC6240: F(old) = 2.6, 5.2, 10.4
-1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
log " (µm)

Parameters vs. NGC 6240
• C parameter
• f(UCHII)
• f(old)
• A(V)
log!F ! (erg s -1)
44.0
43.0
42.0
41.0
40.0
39.0
NGC6240: A(V) = 1.4, 1.9, 2.4
-1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
log " (µm)

Parameters vs. NGC 6240
• C parameter
• f(UCHII)
• f(old)
• A(V)
• Final fit
log!F ! (erg s -1)
44.0
43.0
42.0
41.0
40.0
39.0
NGC6240: SFR = 120; Z = 2.0; log C = 6.5;
A(V) = 1.9; F(old) = 5.2 ; F(UCHII) = 0.15
-1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
log " (µm)

• Arp220 is a
strong ULIRG
• Heavily dust
affected
Now you See It
log!F ! (erg s -1)
43.0
42.0
41.0
40.0
39.0
Arp220
44.0 Arp220: SFR=315; Z=0.4; log C=5.0;
A(V)=2.5; F(old)=0.6 ; F(UCHII)= 0.1
-1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
log " (µm)

• Arp220 is a
strong ULIRG
• Heavily dust
affected
• SB is likely
even more
obscured than
our simple
PDR
Now you Don’t
log!F ! (erg s -1)
44.0 Arp220: SFR=315; Z=0.4; log C=5.0; A(V)(SB) = 20
A(V)=2.2; F(old)=1.0 ; F(UCHII)= 0.7
43.0
42.0
41.0
40.0
39.0
Arp220
-1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
log " (µm)

• Fit to IRS SL+LL
of NGC 7714
• PAH fit justifies
Template
IRS in detail
log!F ! (erg s -1)
44.0
43.0
42.0
NGC 7714: SFR=8.0; Z=1.0: log C=6.0:
A(V)=0; F(old)=1.2; F(UCHII)=0.14
0.5 1.0 1.5
log " (µm)

Models to Measure?
• Created a Series of Starburst models covering expected
parameter space of Metallicity, Pressure and
‘Compactness’
• Compactness parameter, C, controls dust temperature of
SB region and resulting IR peak
• In addition, ‘old’ stellar spectrum, UCHII spectrum (for
same metallicities), diffuse dust emission and extinction
• Reproduce several well known local SB galaxies!

• Spitzer has
revealed many
beautiful things,
including range of
PAH
• Herschel will
show things at the
cooler end, seen
only before with
ISO
Obs. in Space!
log !L ! (erg s -1 )
IRAC
IRS
[OI]63
MIPS
Wavelength (µm)
[OIII]88
[NII]122
PACS
[CII]158
[NII]205
SPIRE