Science with continuum data

ALMA continuum observations:

Physical, chemical properties and evolution of dust, SFR, SED,

circumstellar discs, accretion discs

Effects of dust

Devriendt et al. 99Wavelength

Inte

nsi

ty

Abundance+compositionof dust affect the galaxies’spectral appearance & influence the physical properties (SFR, metallicity,E(B-V))

SED evolution: SFR, reprocessing dust

Tburst=2 Gyr Tburst=0.5 Gyr

The evolution of a galaxy SED

Dwek 2005

HII regions:SN as originof dust

HI regions:later AGBContribution

dust productiondelayedby a few 108 yr

attenuated stellarspectrum

reradiated dustemission

The evolution of dust with metallicity

Dwek 2005

separate contribution from AGB starsto silicate and carbon dust

K-correctionK-correctionSensitivity with 6 antennas

Blain, 04Blain, 04 Griffin, 05Griffin, 05

Flux stays constant

The covering factor of dust in AGNs from the SED

12 14 16 18 20

-2

0

Log

log

F

Opt.-UVX-ray

IR

dust

covering factor YIR-bump

Blue-bump

local AGN

The FIR measures the IR bump of high-z QSO and Seyfert -> evolution of dust covering factor and obcuration at high-z

SEDs of QSOsSEDs of QSOsand RGsand RGs

ISO+MAMBO+ISO+MAMBO+SCUBASCUBA

SEDs SEDs reflectreflectdust distributiondust distributionaround the heatingaround the heatingsource + nature ofsource + nature ofthe heating sourcethe heating source

Haas et al., 2005Haas et al., 2005

Protostar developmentProtostar development The continuum evolvesas the star evolves

High mass star forming regions

• ALMA will resolve continuum emission on ~100AU scales in high-mass (50-100 M) star forming regions

- are there accretion disks in massive protostars and how do they look like?

- to which extent are massive protostellar core fragmented/clustered?

- how does high-mass star formation proceed?

coalescence of lower mass objects requires extremely dense clustering

via disk accretion as is the case for low mass star formation?

• it seems well documented observationally that the disk accretion scenario plays a major role at least for moderately massive protostars (10-20M).These are rare, distant, and clustered star formation adds to make them difficult to observe with current facilities.

IRAS 05358+3543

Protobinary system at projectedseparation of 1700AU

multiple molecular outflows?

SED changes with grain chemical and physical properties

Grain Radius Relation Grain Radius Relation = Q = Qprpr/(/(a)a),a: grain density and radius, Q,a: grain density and radius, Qprpr radiation pressure radiation pressure

Log

[]

Log[a(m)] Models run

Amorphous Silicates

Crystal. Silicates

Amorphous Carbon

Graphite poor

Dust emissivity depends on chemestry and grain size

Graphite rich

Single Grain Size, Single Composition Disk SED

C400

MgFeSiO4

Mg 1.9Fe 0.1SiO4

C1000

Mg0.6Fe0.4SiO3

MgSiO3

Small grainsSmall grains

Intermediate grainsIntermediate grains

Large grainsLarge grains

SEDs depend on chemicalcomposition

SED of a dust diskSED of a dust diskgenerated by an outer generated by an outer beltbeltof planetesimals with of planetesimals with innerinnerplanets is fundamentallyplanets is fundamentallydifferent from that of thedifferent from that of thedisk without planets.disk without planets.

Disc + planet

dust emission from aface-on disc with a planetALMA 900GHz simulations

Integration time 8 hours;10 km baselines;30 degrees phase noise

1 Mjup 0.5 M 5 MJup 2.5 M

orbital radius 5 AUdistance 50pc,total disc mass 10-2 M

orbital radius 5 AUdistance 100pc,total disc mass 10-2 M

Combined beam

Detection of the warm dustin the vicinity of the planetonly for distance 50-100pc

(Wolf & D’Angelo 2005)

Final Disk SED

SED of dust discsin presence of differentplanetary configurations,4 grain chemestry

same particle sizedistribution n(b)db=n0b-q,distance 50pc,total mass 10-10 M

The SED is very sensitive to inclination

[From Van Dishoeck , ARAA 2004]

[Whitney et al. 2004]

Four geometries, ten inclinations

Pole-on edge-on

silicateice

Silicate feature depends ongrain properties and disc geometry

Dust Cycling in GalaxiesGlobal cycle and interstellar processing

Diffuse ISM Molecular Clouds

• CNM

• WNM

• WIM

Star Formation

SN

109 yrs

a few 107 yrs

3 109 yrs

3 106 yrs

Massive stars

Low mass stars

Giants

• cloud envelopes

• dense cores

Dust Spectral Energy DistributionEvidence for dust evolution

=> From the diffuse ISM to molecular clouds, PAHs to large grains

•Comp. Power Mass

•PAH 18% 6%

•VSG 15% 6%

•BG 67% 88%

Variations in PAH abundance in the diffuse ISM and PDRs Enhanced VSG abundance in low density gas

(the Spica HII region)

Cold dust associated with densemolecular gas: lower temperature,larger far-IR emissivity,no small grains

Dust SED/Composition

=> Enhanced VSG abundance factor ~ 5 : shock processing ?

Dust in the Spica HII region