Star Formation/ISM with Herschel

1
Star Formation/ISM with Herschel

• Malcolm Walmsley (Arcetri)
• Floris van der Tak (MPIfR,Bonn)

2
Star Forming Regions are complex

• Such as DR21 at roughly 3 Kpc (Marston et al.
  IRAC)

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

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

5
Serpens at 3mm and 100 microns (Testi priv.comm)
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

7
The SED is very sensitive to inclination

• .... But only at short wavelengths (less than 100
  mu)

From Van Dishoeck , ARAA 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
9
Water may be key to kinematics

• Modeling it will be a challenge. Take for
  example our best guess at GL2591 (van der Tak)

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
11
Present Models are simplistic

• But suffice to explain presently available data
  from ODIN, SWAS, and ISO

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)

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.)

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 ...