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Star Formation/ISM with Herschel PowerPoint Presentation
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Star Formation/ISM with Herschel

Star Formation/ISM with Herschel

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Star Formation/ISM with Herschel

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  1. Star Formation/ISM with Herschel Malcolm Walmsley (Arcetri) Floris van der Tak (MPIfR,Bonn) Dusty04, Paris, Oct. 27-29 2004

  2. Star Forming Regions are complex • Such as DR21 at roughly 3 Kpc (Marston et al. IRAC) Dusty04, Paris, Oct. 27-29 2004

  3. Fundamental steps forward with Herschel • PACS : Maps of star forming regions in continuum and OI 63 micron line • SPIRE : Maps on the large scale (eg of galactic plane, see Molinari HIGAL poster) • HIFI : Water and detailed kinematics of star forming regions Dusty04, Paris, Oct. 27-29 2004

  4. Why PACS is so important • High spatial resolution at the max. of the SED of most star forming regions (roughly 10 arc seconds or 0.1 pc at 3 kpc). This implies : • A) The capacity to separate the main sources of luminosity • B) The capacity to make maps with similar resolution to that available in the mm-submm • C) Basis for models at all wavelengths • For example, following comparison of Serpens as seen today at 3mm and as “expected” with PACS Dusty04, Paris, Oct. 27-29 2004

  5. Serpens at 3mm and 100 microns (Testi priv.comm) Dusty04, Paris, Oct. 27-29 2004

  6. At different wavelengths, different energy sources • It is often unclear where the main energy source is. For example HMPOs with embedded protostars as in IRAS23889 (Fontani et al., Molinari et al.) • ISOCAM (left) and VLA 3cm (right) show that early B stars external to molecular core influence energetics Dusty04, Paris, Oct. 27-29 2004

  7. The SED is very sensitive to inclination .... But only at short wavelengths (less than 100 mu) [From Van Dishoeck , ARAA 2004] Dusty04, Paris, Oct. 27-29 2004 [Whitney et al. 2004]

  8. OI line mapping HH 46-47 • Will be fundamental for measuring outflow rate (see Ceccarelli et al. for OI with KAO) • Important also for PDRs • Distinguishing between them requires PACS resolution [SPITZER: Noriega-Crespo e t al. 2004] Dusty04, Paris, Oct. 27-29 2004

  9. Modeling it will be a challenge. Take for example our best guess at GL2591 (van der Tak) Water may be key to kinematics Dusty04, Paris, Oct. 27-29 2004

  10. The youngest objects have most water • In particular, water seems to be present in Class 0 envelopes and outflows [ODIN: Hjalmarson et al. 2003] [ISO: Nisini et al. 2000, Benedettini et al. 2003] Dusty04, Paris, Oct. 27-29 2004

  11. Present Models are simplistic • But suffice to explain presently available data from ODIN, SWAS, and ISO Dusty04, Paris, Oct. 27-29 2004

  12. A lesson from the above models • The HIFI Band 6 (high freq) lines tend to be in absorption against the continuum • These transitions should tell us about the kinematics along the line-of-sight to the protostar • The low freq water lines will tell us about the extended outflow (HH Objects) Dusty04, Paris, Oct. 27-29 2004

  13. Then there are the PDRs • Finding out ( perhaps from OH) just where ice evaporates in PDRs could be very fundamental • Then there will be new species (see Fuente et al.) Dusty04, Paris, Oct. 27-29 2004 [From Van Dishoeck, ARAA 2004]

  14. Conclusions Combining PACS with HIFI is the best strategy for understanding protostars But history tells us that the future revels in the unexpected ! Spectral scans in the THz range may provide the surprise ... Dusty04, Paris, Oct. 27-29 2004