Extragalactic science with the Herschel Space Observatory

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Extragalactic science with the Herschel Space
Observatory

• Marc Sauvage
• CEA/DSM/DAPNIA
• Service d'Astrophysique
• UMR AIM

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The Herschel Space Observatory

• A European Space Agency (ESA) mission with a NASA
  participation.
• 3.5 m, passively cooled (80 K) telescope in
  space.
• Located at the L2 Lagrange point of the earth-sun
  system.
• Operating in the Far-Infrared to Submillimeter
  range (60-700 µm).
• Cryogenically and actively cooled instruments
  (detector temperature lt 1 K).
• 3.5 years nominal lifetime.
• OfficialLaunchDate August 2007.

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Herschels science objective in a nutshell

• Turn a nice and simple grey-body curve into a
  complicated mess of broad solid-state features
  underlying a forest of lines

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More seriously

• Observe star-forming galaxies in a range where
  they emit most of their flux, taking advantage of
  the redshift

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Herschel's payload
Herschel will cover the FIR-Submm with three
instruments
HIFI High resolution heterodyne spectrometer
Wavelength coverage 157-625 µm Single Beam
12-40 High spectral resolution (up to 107)
Limited capacities for extragalactic science
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Herschel's payload
Herschel will cover the FIR-Submm with three
instruments
Photometer 3 bands at 75, 110 and 170
µm 1.8x3.5 fully sample field of view Beam size
6, 8 and 12 Spectrometer Imaging provided
through image slicer 0.8x0.8 R1000-2000
PACS Bolometer camera and low resolution
photoconductor spectrometer 60-200 µm
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Herschel's payload
Herschel will cover the FIR-Submm with three
instruments
Photometer 3 bands simultaneously at 250, 360
and 520 µm 4x8 field of view (not fully
sampled) Beam size 18, 25, 36 Spectrometer 200
-670 µm 2.6 circular field of view (not fully
sampled) R20-gt1000 (FTS)
SPIRE Bolometer camera and fourier transform low
resolution spectrometer 200-600 µm
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Extragalactic Science with Herschel
Note Herschel was built to make surveys but,
galaxy deep surveys are not the only kind of
surveys
gt1/3 of the time will be dedicated to Galactic
star formation.
SPIRE PACS will be the instruments of choice
for distant or faint extragalactic objects
Sensitivities as of almost today SPIRE PS
imaging 3-10 mJy 5s 1hr (obs. mode dependent, but
all three bands) PACS PS imaging 3 mJy 5s 1hr
(two bands simultaneously)
Confusion will be the main limitation of
extragalactic science with Herschel
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Observing with Herschel
This will be a déjà-vu situation (Herschel is
borrowing a lot from Spitzer)
Science timeline

• L-21m Key Programs GT submitted
• L-18 Key Programs GT published
• L-15 Key Programs OT submitted
• L-12 Key Programs OT published
• L-9 cycle 1 GT submitted
• L-6 cycle 1 GT published
• L Launch
• L9 cycle 1 OT submitted
• L12 cycle 1 OT published
• L21 cycle 2 GT submitted
• L24 cycle 2 GT published
• L27 cycle 2 OT submitted
• L30 cycle 2 OT published
• L42 nominal end of mission

• Four program categories
• Garanteed Time (32)
• Key programs
• Regular projects
• Open Time (68)
• Key programs
• Regular projects

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Current situation
Instrument Consortia have prepared a relatively
detailed version of their Key Programs (but these
over-use the available time). Still to be done is
the negotiation between consortia regarding the
program contents (competition on GT is not
allowed)

• Spectral survey of starburst and AGNs
• Photometric survey of the local volume
• Photometric survey of active galaxies
• Imaging and spectral study of nearby galaxies
• Imaging and spectral study of dwarf galaxies
• Galaxy deep surveys
• Cosmic IR background
• Evolution of the star formation rate and IR
  luminosity
• Environment effects
• AGN contribution
• Extreme galaxies at very high redshifts

The Programs
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Contributing to the Herschel Surveys
For most of the surveys objective, the guaranteed
time available is not sufficient.
Open time key programs will be necessary to reach
these objectives.

• Build your own consortium (in the spirit of the
  Spitzer Legacy Programs).
• Join existing initiatives and for this contact
  Steve Eales (Steve.Eales_at_astro.cf.ac.uk) or visit
  http//astronomy.sussex.ac.uk/sjo/extrahot/