Galactic Star Formation Science
with Integral Field Spectroscopy
Tracy Beck, STScI
Galactic Star Formation Science
with Integral Field Spectroscopy
• Introduction to the formation of sun-like stars in the Milky Way
• Studies of star formation (SF) with IFUs– First uses of IFUs for SF science– Herbig Haro Objects– Young Star Binaries
• Star Formation at high contrast with IFUs: A Search for IR H2 Emission from the Disks of Young Stars
• Cutting Edge Science: Laser-Fed AO IFU spectroscopy of young stars
• Prospects for JWST and the ELTs
Formation of Sun-like Stars in the Milky Way
Sub-mm continuum of protostellar cores
Shirley et al. (2000)
Formation of Sun-like stars in the Milky Way
Young stars with Circumstellar disks + extended Envelopes (“Class I” Protostars)
HST NICMOS Imaging of Protostars (Padgett et al. 1999)
Formation of Sun-like stars in the Milky Way
Young stars with Circumstellar disks, no envelope material left (“Class II” Protostars,
“Classical” T Tauri Stars)
Orion ProplydsO’Dell & Wen (1994)
Formation of Sun-like stars in the Milky Way
Dust disk dissipates in <1Gyr timescale
Meyer et al. (2008)
Beta Pic Debris Disk
Formation of Sun-like stars in the Milky Way
“Class II” Protostars with Disks + Outflows – “Classical T Tauri Stars”
IFUs in Star Formation Science
Herbst et al. “A Near-Infrared Spectral Imaging Study of T Tau” 1996 AJ v.111, 2403
MPE 3D w/ Calar Alto (3.5m)H and K-band
Observations of T Tau
8”
IFUs in Star Formation Science
Lavalley et al. “Sub-arcsecond morphology and kinematics of the DG Tauri jet in the [O I]λ6300 line” 1997 A&A v.327, 671
IFUs are very powerful tools for spatially resolving emission line structures in the environments of bright T Tauri Stars
Herbig Haro Objects
• HH Objects: – optical/infrared tracers of YSO jets, seen where
jets from young stars plow into ambient cloud material and shock the gas into emission
– Pure emission line objects – viewed in optical/infrared permitted and
forbidden transitions – H, [O I], [N II], [S II], [FeII], trace atomic gas excited by shocks
– Shock-excited H2 emission in the IR Natural IFU Sources
Beck et al. 2004, 2007, Lopez et al. 2008, 2010 Giannini et al. 2008
HH 111
HH 46/47
Herbig Haro Objects
• HH 99B: – Very sensitive VLT + SINFONI
observations– 170+ Emission lines detected– Many very high excitation
lines of H2 and [Fe II]– Bow-shock apex shows
extremely high temperature - T~6000K - revealing that the H2 molecule persists in these very high temperature regions
Giannini et al. “Near-infrared, IFU spectroscopy unravels the bow-shock HH99B“ 2008, A&A v.481, 123
H2 1-0 S(1) 2.12m H2 2-1S(17) 1.758m
[Fe II] 1.644 m [Fe II] 1.749 m
[P II] 1.188 mHI Pa 1.28 m
Head of the Bow Shock
Wings of the Bow Shock
Young Star Binaries
• Most stars (50-60%) form as binary or higher order multiple systems
• Understand young star binary characteristics, particularly disk and mass accretion evolution
• The more massive primary star often has more active mass accretion, indicating a larger circumstellar disk reservoir of mass. I.e., preferential accretion from circumsystem material onto the more massive star in a binary
• Spatially Resolved Observations of Young Star binaries 0.”1 to ~1” separations, Programs ongoing using NIFS, SINFONI & OSIRIS
Young Star Binaries – Z CMa
• OASIS observations in [OI] 6300A
Garcia et al. “Spatially resolved spectroscopy of Z Canis Majoris components” 1999, A&A v.346, 892
• Protostellar B star (Herbig Be star) primary, FU Ori eruptive variable companion
• System has become a prototype for understanding eruptive mass accretion in young star binaries
0.”1 binary observed with OASIS – 0.”11
microlenses!
Young Star Binaries – Z CMa
• Keck OSIRIS [Fe II] 1.644m observations of Z CmaWhelan et al. “The 2008 Outburst of Z CMa: The First Detection of Twin
Jets” 2010, ApJL v.720,L119
• The Massive Herbig Be star does drive the parsec scale outflow!•The companion is discovered for the first time to drive its own small scale jet
•First detection of a collimated jet from a FU Ori outbursting variable star!
High Contrast IFU Spectroscopy in Star Formation – Gas in Circumstellar Disks
HH 30
Dust in Circumstellar Disks – Traced by infrared excessEmission, seen in scattered light images of T Tauri starsGas in Circumstellar Disks – As much as 99% of the mass in circumstellar disks is in GAS not DUST
Disk Gas is traced by:• mm molecular observations of cold outer disk gas• IR emission species trace warm gas from ~terrestrial regions of disks
Most studies cannot spatially resolve the gas in the inner disk regions and measure trace components of the disks, ~70% of the disk by mass is in H2
The Search for IR Molecular Hydrogen Gas in Young Star Disks
FWHM ~0.”1
Beck et al. “Spatially Resolved Molecular Hydrogen in the Inner 200 AU Environments of T Tauri Stars” 2008 ApJ, v.676, 472
Gemini + NIFS IFU
observations of six T Tauri Stars – all
known to drive YSO outflows
K-band Continuum
Images
The Search for IR Molecular Hydrogen Gas in Young Star Disks
Herbig Haro Flows
From Classical T Tauri stars w/
outflows, H2 arises from
shocked emission
surrounding the HH flows
Beck et al. “Spatially Resolved Molecular Hydrogen in the Inner 200 AU Environments of T Tauri Stars” 2008 ApJ, v.676, 472
IFU Observations of T Tau Across a Decade…
Herbst et al. 1996MPE 3D Data from Calar Alto 3.5m
Jan. 1995
Beck et al. 2008NIFS Data from Gemini-N 8m
Oct. 2005
The Search for Molecular Hydrogen Gas in Young Star
Disks
• VLT + SINFONI Observations of T Tau, detection of H2 from the face-on disk around T Tau N?
Gustofsson et al. “Spatially resolved H2 emission from the disk around T Tau N”
2008
H2 EmissionFlux
H2 Velocity
H2 Velocity Dispersion
T Tau in [Fe II]
Where is the IR Molecular Hydrogen Gas in Young Star Disks?
• Doing a Gemini + NIFS IFU survey of additional young stars, more than doubling the past sample – this includes stars that have evidence for dust disk gaps (from IR SED shapes), and/or “disk-like” H2 from past long-slit observations
Highlight = GG Tau A, 0.”3 binary young star, with the prototypical “Circumbinary Ring” of dust (Roddier et al. 1996)
Subaru CIAO Observations of GG Tau A
*
Circumbinary Ring seen in scattered light
3”
T. Beck, J. Bary et al. “The Search for Spatially Resolved IR H2 from the Disks of
Classical T Tauri Stars” (in prep.)
The Search for IR H2 from a Disk High Contrast for Star Formation
NIFS 2.12m continuum image of the 0.”3 GG Tau A binary
IR Spectrum of GG Tau A – typical of young starsBr
H2??
Fe I
Looking for a signal of ~few 100 cts, on a continuum of 30K+ cts, with a photospheric Fe I feature in the way!
H2!!
The Search for IR Molecular Hydrogen Gas in Young Star Disks
T. Beck, J. Bary et al. “The Search for Spatially Resolved IR H2 from the Disks of Classical T Tauri Stars” (in prep.)
The Search for IR Molecular Hydrogen Gas in Young Star Disks
T. Beck, J. Bary et al. “The Search for Spatially Resolved IR H2 from the Disks of Classical T Tauri Stars” (in prep.)
H2 Emission in the Environment of GG Tau A
• H2 2-1 S(1) / 1-0 S(1) line ratio not indicative of fluorescent pumping by UV photons, is consistent with X-ray heating of the gas• Gas/Dust in Protostellar binaries should NOT exist (Artymowicz & Lubow 1994):
• Circumstellar: at spatial locations beyond ~1/3 of the semi-major axis of the binary (disk truncation)• Circumbinary: at spatial locations within ~3x the semi-major axis of the binary (gap clearing)
• Clearing timescale ~100’s of years!
H2 1-0 S(1) @ 2.12m
The Search for IR Molecular Hydrogen Gas in Young Star Disks
T. Beck, J. Bary et al. “The Search for Spatially Resolved IR H2 from the Disks of Classical T Tauri Stars” (in prep.)
H2 1-0 S(1) @ 2.12m
40AU – Pluto’s semi-major axis
H2 1-0 Q(1) @ 2.40m
Cutting Edge SF Science: Laser-Fed AO Observations of Young Stars
Perrin et al. “Laser Guide Star Adaptive Optics Integral Field Spectroscopy of a Tightly Collimated Bipolar Jet from the Herbig Ae star LkH 233” 2007 ApJ, v.670,
499
• Comparably few detailed spatially resolved observations of collimated outflows toward protostars with higher mass than the sun-like T Tauris.
• Keck Observatory LGS AO + OSIRIS IFU Observations of the very young Herbig Ae star LkH 233
• Investigate whether the similarity on large spatial scales between outflows from T Tauri and Herbig Ae stars still holds true on finer spatial scales.
Pushing to Higher Mass:
Cutting Edge SF Science: Laser-Fed AO Observations of Young Stars
Perrin et al. “Laser Guide Star Adaptive Optics Integral Field Spectroscopy of a Tightly Collimated Bipolar Jet from the Herbig Ae star LkH 233” 2007 ApJ, v.670,
499
Cutting Edge SF Science: Laser-Fed AO IFU Observations of Young Stars
• IRAS 04158+2805 = young proto-object in the Taurus SFR (d~140pc)
• Seen in the optical largely in scattered light, with a ‘bipolar’ nebula structure typical of opaque disk material along the mid-plane (Glauser et al. ’08), interpreted as a source with a disk inclined by ~63o
• YOUNG! (<~1Myo!) w./ M6 type, commonly adopted SpT for young BD limit
• HR Diagram fitting = substellar ~0.05Msolar (large uncertainty in models)
• Andrews et al ‘08 detected the disk in sub-mm, high spatial resolution dust continuum and CO gas! extends out to >~500AU from the central source - MASSIVE disk with ~1000+ AU total extent!
• Stellar mass estimate + extended massive disk! – Mdisk / Mstar ~15-20%!
HST Image From Glauser et al. 2008
Beck et al. “Laser Fed Adaptive Optics Imaging Spectroscopy of the CandidateProto-Brown Dwarf IRAS 04158+2805”
in Prep.
Pushing to Lower Mass:
Laser-fed AO Spectral Imaging, IRAS 04158+2805
– Gemini LGS AO w/ NIFS = Goal - Determine if H2 gas traces disk material in the BD candidate environment - it doesn’t!
– Data reveals fspatially resolved 2-D spectral images of a well collimated jet from a very young BD candidate
– BLUE-shifted, collimated [Fe II] jet associated with the brighter lobe of the scattered light nebulosity - no redshifted jet detected
– Jet Orientation consistent w/ 63o viewing disk inclination
1.644m [Fe II](Jet!)
2m K-band(Scattered Light!)
2.12m H2
(Wide-Angle Outflow!)
100
AU
Beck et al. “Laser Fed Adaptive Optics Imaging Spectroscopy of the CandidateProto-Brown Dwarf IRAS 04158+2805” in Prep.
Laser-Fed Spectral Imaging of BD Laser-Fed Spectral Imaging of BD EnvironmentsEnvironments
• Laser-Fed AO on large ground-based telescopes is a powerful means to reveal the inner environments of BDs at high spatial resolution using IR emission lines…
• Complication = BDs are optically very faint, but you need an optical tip-tilt guide star! (TTGS)
• Observations of IRAS 04158+2805 were only possible with Gemini +LGS AO because of the nearby r~17.6 magnitude guide star
AO TTGS Area
TTGS r~17.6mag IRAS 04158+2805
K~11.6 mag, R~21
Gemini Observing Tool View
The Future: SF Science with the JWST and ELT IFUs
FAINTER!FAINTER!More Distant– Probe the Star
formation process to low mass M
stars, approaching the BD limit in the
LMC and SMC!
More Distant– Probe the Star
formation process to low mass M
stars, approaching the BD limit in the
LMC and SMC!
Higher Mass – Massive O&B stars form in very dense
cocoons of gas+dust, pierce
through the extinction to see
the forming stars!
Higher Mass – Massive O&B stars form in very dense
cocoons of gas+dust, pierce
through the extinction to see
the forming stars!
Lower Mass – BDs and Free-Floating Planets in nearby
star forming regions like Taurus
and Orion!
Lower Mass – BDs and Free-Floating Planets in nearby
star forming regions like Taurus
and Orion!
Younger – Sun-Like stars at earlier
epochs of formation – the
“Class I” phase w/ envelope material remaining, or even
younger!
Younger – Sun-Like stars at earlier
epochs of formation – the
“Class I” phase w/ envelope material remaining, or even
younger!
Spectral Imaging of young Star Spectral Imaging of young Star Environments with Environments with JWSTJWST
• The James Webb Space Telescope - operating at L2 in ~2014
• 6.5m Segmented Primary• 4 Science Instruments:
– NIRCam - Near-InfraRed Camera
– NIRSpec - Near-InfraRed Spectrograph w/ IFU!
– TFI - Tunable Filter Imager– MIRI - Mid-InfraRed
Instrument w/ IFU
The James Webb Space Telescope
NIRSpec and MIRI have Integral Field Units for very sensitive high-contrast spectral imaging of young star environments.
A schematic view of the JWST focal plane, including the placement of the science
entrance apertures for each instrument.
The Future: SF Science with IFUs on the ELTs
GMT
TMT
Nearby T Tauri stars are bright for large aperture telescopes – but we really need the ELT spatial resolution
to push our observations to the ~Jupiter environs!
When considering properties for IFUs for large telescopes, please don’t forget about star formation science! & Consider
a high spectral resolution IFU mode for the IR…!!
For Kinematics and spectral line detection/characterization, star formation science
greatly benefits from HIGH spectral resolution! (R~20,000 or greater)
Mandell et al. (2009) R~27,000
The Future: Next Generation Observations of T Tau?
Herbst et al. 1996Data from Jan.
1995 Beck et al. 2008Data from Oct. 2005
?THANKS!! For Your Attention!
Next GenerationIFU View of T Tau
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