ALMA ES capabilities: Distant Galaxies

Alexandra Pope (UMass Amherst)JWST Workshop STScI BaltimoreJune 8, 2011Mid-Infrared Observation of High Redshift Galaxy Evolution

-understanding the assembly of galaxies one of the main science goals of JWST-what we learned from Spitzer, pose good questions for JWST- Also think about where we will be at in 2017-1018 with other other IR/submm facilities1Most star formation activity occurs behind dust

Chary & Pope 2011Bouwens et al. 2009Lagache et al. 2005Most stellar mass and AGN growth occurs at z~1-3

sub-mmQSOsSquares: optical/near-IRCircles: far-IR/sub-mmWall et al. 2008Dickinson et al. 2003

Le Floch et al. 2005ULIRGsLIRGsNormalTotalMost of the z~1-3 stellar mass growth occurs in LIRGs (and ULIRGs)

Most of the z~1-3 stellar mass growth occurs in LIRGs (and ULIRGs)Murphy et al. 2011Ultra-luminous infrared galaxies (ULIRGs) A rose by any other name would smell as sweet Local

BzKsSMGsDOGsOFRGsBump sourcesC-thick AGN Complete samples of galaxies down to a given LIR Not biased by AGN, dust temperature, detection limit, etc. Mostly major mergers?z ~ 26-names dont matter it is just what things areUltra-luminous infrared galaxies (ULIRGs) A rose by any other name would smell as sweet Local

BzKsSMGsDOGsOFRGsBump sourcesC-thick AGN Complete samples of galaxies down to a given LIR Not biased by AGN, dust temperature, detection limit, etc. Mostly major mergers?z ~ 27-names dont matter it is just what things are

Submillimeter Galaxies (SMGs) high redshift z~2 (Chapman et al. 2005, Pope et al. 2005) massive Mgas~31010M M~1011M (Greve et al. 2005, Borys et al. 2005) high IR luminosities => SFR~1000Myr-1 assuming no AGN! (Lilly et al. 1999, Chapman et al. 2005, Pope et al. 2006)

sub-mmBorys et al. 2005Pope et al. 2005Chapman et al. 20058JPGSpectral energy distribution (SED) of high redshift submillimeter galaxies (SMGs)Rest Wavelength (m)

Luminosity density (WHz-1)HSTVLASCUBAMIPSIRACHerschelIRS Circa 2011: Well sampled SED for ULIRGs z~1-3 Spectroscopy can provide a probe of the underlying radiation field Mid-IR spectroscopy is sensitive to dust which is dominating the SFRDOutstanding issues: Projects for JWSTResolve the 24m background detect warm dust in faint LBGs which contribute significantly to the IR background; SMGs out to z~7Detect PAH emission in lower luminosity galaxies ( Does this mean SMGs are AGN dominated ? Log [LIR(L)]SB fractionSMGsTran et al. 200121JPG

Starburst: Polycyclic aromatic hydrocarbons (PAH) + extinctionAGN: power-law + extinctionSpitzer Mid-IR Spectroscopy of SMGsSMG composite spectrumMid-IR SED of SMGs is starburst dominated : small contribution from AGN (> 1024cm-2See Alexander et al. 2008 for more discussion on IRS identified Compton-thick AGN25JPGWhat about lower luminosity galaxies?

Siana et al. 2008, 2009; see also Rigby et al. 2008, Gonzalez et al. 201026JWST/MIRI spectra of z~2 LIRGsSpitzer IRS took spectra of ~200 galaxies at z>1 - the majority of these are ULIRGs, with a few LIRG learnt a lot of AGN vs SF in the most luminous galaxies

JWST/MIRI will be able to take spectra of all LIRGs and at much higher spectral resolution (R~3000!)

Armus et al. 2007Spitzer high resolution (R~600) only possible for local galaxiesGetting more info out of a PAH spectrum

Relative PAH strengths tell you about the size distribution and ionized state of the dust grains; compared to large grains you can constrain the strength of the radiation fieldDraine & Li 2007Smith et al.2007-draine&Li: Y-axis=efficiency for radiating in different 28Getting more info out of a PAH spectrum

Draine & Li 2007Pope et al. 2008

JWST/MIRI spectra of z>4 galaxies?Spitzer/IRS saw PAHs out to z~4

JWST/MIRI will see the 6.2m PAH out to z~3.5 and the 3.3m PAH out to z~7 track down the earliest dust and learn how it formed

24 hr Spitzer IRS spectrum of the z=4 SMG GN20Riechers et al. in preparation3.3m PAH feature in local galaxiesEW provides a cleaner AGN indicator

Imanishi et al. 2010

3.3m PAH at high redshift

Sajina et al. 2009What if SMGs are really powered by AGN?In order to have most of the LIR from the AGN and have the PAHs survive, you need to have an unusual geometry, e.g. non PAH dust shielding more PAH dust from AGN radiation or just really extended distribution of small grains

Can we resolve this??

What if SMGs are really powered by AGN?SMGs have sizes of :~0.6 arcsec ~5kpc (Engel+10, Younger+08)

JWST/MIRI has a resolution of 0.3 arcsec at 10m we can try to resolve the 3.3m PAH emission in galaxies at z 50%38JPGSED fitting with Spitzer/IRS + Herschel data

AGN dominated (mid-IR)SF dominated (mid-IR)Warm dust (100K)Cool dust (~30K)39JPG

Composite SEDs Kirkpatrick et al. in prep

Kirkpatrick et al. in prepComposite SEDs Influence of the AGN on IR colors

Hatziminaoglou al. 2010

Kirkpatrick et al. in prep42JPGValtchanov et al. 2011Synergy with ALMA: Constraining ISM conditionsIndeed it is expected that CO and PAH emission will be roughly correlated in galaxies as they are both expected to trace star formation and both appear in PDRs43Valtchanov et al. 2011Synergy with ALMA: Constraining ISM conditionsXLPAHIndeed it is expected that CO and PAH emission will be roughly correlated in galaxies as they are both expected to trace star formation and both appear in PDRs44Summary We have learnt a lot from Spitzer this puts us in a great position to plan innovative projects for JWST

Several key areas where still have a lot to learn about dust in high redshift galaxies: Directly detect dust in the galaxies which dominate the SFRDUnderstand the detailed composition of dust at high redshift which constrains the production mechanismsRelative heating of dust from starbursts and AGN activity

JWST together with ALMA will be a powerful duo for attacking these problems But first, what we know from Spitzer45