Selecting the best targets for JWST: My personal journey as a MIRI team scientist

7 March 2013

Selecting the best targets for JWST: My personal journey

as a MIRI team scientist

Margaret Meixner (STScI, JHU)March 7, 2013

Hubble Science Briefing

Hubble Science Briefing - Margaret Meixner

Outline of Talk• My personal story as a JWST/MIRI science team member• Astronomers prepare now to use the power of JWST

(James Webb Space Telescope)• Spitzer and Herschel space observatories find thousands

of forming stars in the Magellanic Clouds– Large Magellanic Cloud (LMC)

– Small Magellanic Cloud (SMC)

• My JWST programs on star formation in the Magellanic Clouds

• How JWST will discover more forming stars in nearby, but more distant galaxies

2Hubble Science Briefing – Margaret Meixner7 March 2013

Margaret Meixner:

Member of the JWST/MIRI Science Team


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JWST Sensitivity:-typically detects at an order of magnitude fainter than recent and current observatories

-lower is better!

Hubble Science Briefing – Margaret Meixner7 March 2013

JWST Sensitivity

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JWST launches in 2018;appropriate target lists must be developed now…


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James Webb Space Telescope (JWST)


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Integrated ScienceInstrument Module

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Integrated Science Instrument Module (ISIM)


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Integrated Science Instrument Module (ISIM)


NIRSpec

NIRCamNIRISS

MIRI

James Webb Space Telescope: Webb ~2018

117 March 2013

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The Mid-InfraRed Instrument(MIRI)


spectrograph

Imager

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MIRI detector


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MIRI Arrives at Goddard


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MIRI Inspected at Goddard


MIRI Team


Why the Magellanic Clouds?

They act as a good astrophysical laboratory:• They are nearby: ~50 kpc (LMC) and ~60 kpc (SMC) [the Andromeda

Galaxy is about 16 times farther away]

• Mean metallicity (Z)* is similar to metallicity of the interstellar medium during Universe’s peak star formation epoch (z**~1.5)

– LMC: Z~0.5 x Z

– SMC: Z~0.2 x Z

• Known tidal interactions between LMC and SMC, possibly the Milky Way

• Long History of Studies & used as a proving ground:

– Ideal Case study for galaxy evolution

*metallicity (Z) = percent of elements other than hydrogen and helium**z = redshift


LMC, SAGE- MIPS: 70 m

Meixner et al. 2006

http://sage.stsci.edu/SAGE team Meixner et al. 2006

IRAC 3.6 m: old (evolved) stellar populationsIRAC 8.0 m: dust emission from ISMMIPS 24 m: new massive star formation

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Spitzer Survey of the Large Magellanic Cloud (LMC): Surveying the Agents of Galaxy Evolution (SAGE)


7 March 2013 JWST briefing - Margaret Meixner

Spitzer wavelengths detect dust, stars & gas

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http://www.spitzer.caltech.edu/images/2627-sig07-011-The-Spitzer-Space-Telescope-Spectrum

SPIRE 250 m

PACS 160 m

PACS 100 m

HERITAGE Team;Meixner et al.submitted


LMC: Herschel Inventory of The Agents of Galaxy Evolution (HERITAGE)

http://sage.stsci.edu/SAGE SMC teamGordon et al. 2011

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old (evolved) stellar populationsnew massive star formation

dust emission from ISM

SAGE-SMC: Spitzer IRAC & MIPS Imaging ofSmall Magellanic Cloud (SMC)


SPIRE 250 m PACS 160 m PACS 100 m

HERITAGETeam;Meixner et al.submitted

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SMC: Herschel HERITAGE


Goal of Spitzer and Herschel surveys: • to study lifecycle of baryonic matter using infrared and

submillimeter emission from dust.

Why is studying dust important?• Dust is present at the key transition points of this life cycle

• It is present in the ISM (which is the origin of the cycle)

• Dust enshrouds the young stellar objects as they form

• Dust is produced in the stellar winds of dying stars and in the explosive supernovae

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Why is studying dust important?


credit: http://hea-www.cfa.harvard.edu/CHAMP/EDUCATION/PUBLIC/ICONS/

Intermediate mass stars High mass stars

Tracing the Lifecycle of Baryonic Matter:


credit: http://hea-www.cfa.harvard.edu/CHAMP/EDUCATION/PUBLIC/ICONS/

Intermediate mass stars High mass stars

Tracing the Lifecycle of Baryonic Matter:

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YSOs


Young Stellar Object Evolutionary Stages

Herschel

Spitzer

Hubble & JWST

Young Protostar:Main Accretion Phase

Evolved Accreting Protostar

Thick disk, accreting,Herbig Ae/Be

Thin disk, T-Tauri

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Hubble & JWSTtime


N 66NGC 602

NGC 346

8.0 m


~1100 YSO candidates; ~900 new

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Spitzer Discovers One Thousand Young Stellar Objects in the SMC

Sewilo et al. submitted


SAGE IRAC 8 m

Spitzer:

~1000 YSO candidates Whitney, Sewilo et al. (2008)

~1200 YSO candidates Gruendl & Chu (2009)

Pre-Spitzer:~20 protostars known

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Spitzer Discovers Two Thousand Young Stellar Objects in the LMC

~1800 unique sources

Star Formation Rate: ~0.1 M/yr


Pre-Spitzer:~20 protostars known

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SAGE IRAC 8 m

Spitzer Discovers Two Thousand Young Stellar Objects in the LMC

Spitzer:

~1000 YSO candidates Whitney, Sewilo et al. (2008)

~1200 YSO candidates Gruendl & Chu (2009)

~1800 unique sources

Star Formation Rate: ~0.1 M/yr


Carlson et al. 2012

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Detailed study by

Spitzer finds low-mass

YSOs(circles)

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Carlson et al. 2012

Detailed study by Herschel finds YSO candidates

(red squares)

JWST simulation

region (next slide)

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JWST imaging tiles on N113 star formation region

Seale & Meixner

JWST will detect solar-like stars with planet forming disks in the LMC!


NGC 602

But it would be useful to get HST data of a field first,as we have for an SMC source

SAGE SMC teamGordon et al. 2011



MIPS 24µmIRAC 8.0µmIRAC 3.6µm, 4.5µm, 5.8µmBlue= HST Optical

Circles= YSOsUnclassified

Stage IStage I/II

Stage II

Carlson, et al. 2010

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Spitzer & HST image of NGC 602

34Hubble Science Briefing – Margaret Meixner

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HST image of NGC 602


JWST will acquire simultaneous spectral and spatial information


Seale, Sewilo, Meixner

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JWST NIRSpec & MIRI Spectroscopy of selected YSOs

Example: N113, a massive young stellar object


Seale et al. 2009

MIRI

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LMC N113: Spitzer spectrum reveals a hot massive star


JWST: NIRSpec & MIRI IFU spectroscopyreveals the environmental composition of forming stars

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ISO SWS spectrumWhittet et al. 1996


JWST can measure a spectrum of any source detected with Spitzer

• In the LMC, we detected 6 million sources

• With Spitzer we measured spectra of only 2000

• The faintest sources were unreachable with Spitzer

• In the time of 10 seconds to 2 hours, we can measure a spectrum of any source.


Pursuing SAGE-like studiesin nearby Galaxies

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• With Spitzer, we imaged the Magellanic Clouds with one minute per pointing.

• With JWST MIRI, we can detect the same types of forming stars in galaxies as far away as 1 Mpc in one minute per pointing.

• The best galaxies should be well studied by Herschel and Spitzer.– the ISM should be mapped in atomic and molecular gas– the stars should be measured and their past well understood


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M31: angular size of galaxy: 190’x60’


M31: 190’ x 2’ strip: total time is ~80 hrs


M33: 0.889 Mpc, 71’x42’


NGC 6822: 0.490 Mpc, 16’x14’


Summary of Talk

• Preparing appropriate target lists for JWST, to launch in 2018

• Spitzer and Herschel space observatories discovered thousands of forming stars in the Magellanic Clouds

• Hubble has surveyed some fields; need more to prepare for JWST

• With JWST I will learn about the nature of the material in forming stars in the Magellanic Clouds:

– Do they contain a similar amount of water and organic materials?

– Do the solar mass stars have enough circumstellar dust to form planets?

• With JWST, I will discover more forming stars in nearby, but more distant galaxies, like M31, M33 and NGC 6822


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Selecting the best targets for JWST: My personal journey as a MIRI team scientist