Outflows and Jets: Theory and Observations Winter term 2006/2007 Henrik Beuther & Christian Fendt Introduction & Overview (H.B. & C.F.) Definitions, parameters, basic observations (H.B) Basic theoretical concepts & models I (C.F.) Basic theoretical concepts & models II (C.F.) Observational properties of accretion disks (H.B.) Accretion disk theory and jet launching (C.F.) Outflow-disk connection, outflow entrainment (H.B.) Outflow-ISM interaction, outflow chemistry (H.B.) Theory of outflow interactions; Instabilities; Shocks (C.F.) 22.12, and Christmas and New Years break Outflows from massive star-forming regions (H.B.) Radiation processes (H.B. & C.F.) Observations of AGN jets (Guest speaker: Klaus Meisenheimer) AGN jet theory (C.F.) Summary, Outlook, Questions (H.B. & C.F.) More Information and the current lecture files:

Optisch Importance of massive stars Great impact on ISM and star clusters, L  M 3 - Outflows and Jets - UV-radiation - Supernovae - The majority of all stars form in clusters, massive stars exclusively. - They produce all heavy elements Problem: With the typical accretion rates known from low-mass star formation, the radiation pressure of the forming massive stars would revert any infall for protostars >10M sun.

Massive Star Formation Modified classical scenario: Wolfire & Cassinelli 1987 Jijina & Adams 1996 Yorke & Sonnhalter 2002 Norberg & Maeder 2002 Keto 2002, 2003 Krumholz et al. 2005, 2006 Banerjee & Pudritz 2005 Coalescence and competitive accretion scenario: Bonnell et al. 1998, 2004, 2004 Stahler et al Bally & Zinnecker 2005 Pudritz & Banerjee 2005 How to differentiate between both scenario? - Molecular outflows and accretion disks - Fragmentation and global collapse - …

“magnetic accretion-ejection structures” (Ferreira et al ): 1) disk material diffuses across magnetic field lines 2) is lifted upwards by MHD forces, then 3) couples to the field and 4) becomes accelerated magnetocentrifugally and 5) collimated Jet launching and early collimation Magnetic field lines (thick) and streamlines (dashed) If F _|_ decreases --> gas pressure gradient lifts plasma from disk surface If F || increases --> radial centrifugal acceleration of plasma F || F _|_ Banerjee & Pudritz 2006

Outflow entrainment - Various outflow-entrainment models: jet-entrainment and wide-angle winds are likely the two most reasonable mechanisms. - Observational tools like pv-diagrams, mv-diagrams and various different jet/outflow tracers allow to constrain the models. Arce et al. 2007

Results of early massive outflow research Seem to be ubiquitous phenomena Very massive and energetic Seemingly less collimated than low-mass flows Different entrainment scenarios proposed (deflection, winds...) However, these results were based on small samples and poor angular resolution (between 21'' and 60'')

Massive molecular outflow maps - Assuming momentum conservation: p out = M out v out = M jet v jet = dM jet /dt v jet t = p jet - With a jet/outflow velocity ratio v jet /v out ~20 and a ratio of outflow rate to the accretion rate of ~0.3, one can estimate accretion rates: --> Mean accretion rate M sun /year high enough to overcome radiation pressure Grey: 1.2mm continuum, contours CO(2-1) wing emission IRAM 30m, Beam 11'' Beuther et al. 2002

Outflow masses versus core masses Accretion rate: M acc = f acc M core /t ff deflection efficiency: f r = M jet /M acc... Multiply both equations and assume momentum conservation f r f acc = M jet /M core = v out /v jet x M out /M core = constant M acc is approximately a linear function of M core (and the mass of the jet is proportional to the core mass).

Outflow properties Mechanical Force Mass Outflow rate Mechanical L

Flashlight effect - With outflow cavities the average gas temperatures are cooler. - Gravitational force stronger in eq. plane. - Radiation escapes through outflow cavities. --> Reduction of radiation pressure and angular momentum problem. Black: gravity Red: no cavity Green, blue, purple: 5, 10, 15 o opening angle Krumholz et al (also Yorke & Sonnhalter 2002)

The pre-UCHII region IRAS Beuther et al IRAM 30m data Grey: 1.2mm Contours:CO(2-1) L bol ~ 6.3x10 3 L sun ; no cm emission --> pre-UCHII region

IRAM 30m, CO(2-1), Beam 11 '' The Outflows in IRAS PdBI + 30m, CO(1-0), Beam 3.9 '' x 3.6 '' blue wing red wing both Beuther et al L bol ~ 6.3x10 3 L sun ; very weak cm emission --> HCHII region, pre-UCHII region

Shocked H 2 emission in IRAS L bol ~ 2x10 4 L sun no cm emission  pre-UCHII region Spectroscopy of the H 2 features reveals similar characteristics to low- mass outflows Davis et al. 2004

A centimeter continuum jet in IRAS GHz K-band & 1.2mm L bol ~6x10 4 L sun Collimated thermal & non-thermal jet Brooks et al Graray et al. 2003

A young UCHII region: G192 Shepherd et al. 1998, 1999 Devine et al [SII] Color contours: CO(1-0) Inlay: mm continuum L bol ~ 3x10 3 L sun Small UCHII at center Collimation con- sistent with wind- blown bubble

The UCHII region W75 Shepherd et al. 2003, 2004 Torrelles et al Cluster of B0.5 to B2 stars associated with UCHIIs L bol ~ 4x10 4 L sun Wide-angle large-scale outflow, is that associated with the small-scale maser outflows?

The luminous UCHII region G5.89 L bol ~ 3x10 5 L sun Harbours O5 star Multiple outflows Sollins et al Watson et al Feldt et al Puga et al. 2006

Position velocity diagrams Beuther et al IRAS , Lebron et al. 2006

(Yorke 2004) W75 N G IRAS IRAS ZAMS No real jet with UCHIIs Pre-ZAMS & Pre-UCHII Jet-like outflows Adapted from Shepherd 2004 Approximate Timescales for massive outflows

An evolutionary scenario Beuther & Shepherd 2005

Summary Massive molecular outflows are ubiquitous phenomena. Jet-like outflows exists at least up to early-B and late-O-type stars. Like in low-mass star formation, some outflows are likely driven by jet-entrainment whereas others are consistent with wide-angle winds. Estimated accretion rates are high enough to overcome radiation pressure. Flashlight effect additional helps reducing radiation pressure in equatorial plane. Hence the observations support the classical scenario that massive star formation proceeds similarly to low-mass star formation. The observations suggests tentatively an evolutionary scenario.

Outflows and Jets: Theory and Observations Winter term 2006/2007 Henrik Beuther & Christian Fendt Today: Introduction & Overview (H.B. & C.F.) Definitions, parameters, basic observations (H.B) Basic theoretical concepts & models I (C.F.) Basic theoretical concepts & models II (C.F.) Observational properties of accretion disks (H.B.) Accretion disk theory and jet launching (C.F.) Outflow-disk connection, outflow entrainment (H.B.) Outflow-ISM interaction, outflow chemistry (H.B.) Theory of outflow interactions; Instabilities, Shocks (C.F.) 22.12, and Christmas and New Years break Outflows from massive star-forming regions (H.B.) Radiation processes (H.B. & C.F.) Observations of AGN jets (Guest speaker: K. Meisenheimer) AGN jet theory (C.F.) Summary, Outlook, Questions (H.B. & C.F.) More Information and the current lecture files: