Extragalactic science with the Herschel Space Observatory Marc Sauvage CEA/DSM/DAPNIA Service d'Astrophysique UMR AIM

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 ( µm). Cryogenically and actively cooled instruments (detector temperature < 1 K). 3.5 years nominal lifetime. OfficialLaunchDate: August 2007.

Herschel’s 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…

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

Herschel's payload Herschel will cover the FIR-Submm with three instruments: HIFI High resolution heterodyne spectrometer Wavelength coverage: µm Single Beam 12-40” High spectral resolution (up to 10 7 ) Limited capacities for extragalactic science

Herschel's payload Herschel will cover the FIR-Submm with three instruments: PACS Bolometer camera and low resolution photoconductor spectrometer µm Photometer: 3 bands at 75, 110 and 170 µm 1.8’x3.5’ fully sample field of view Beam size 6”, 8” and 12” Spectrometer: Imaging provided through image slicer 0.8’x0.8’ R=

Herschel's payload Herschel will cover the FIR-Submm with three instruments: SPIRE Bolometer camera and fourier transform low resolution spectrometer µm Photometer: 3 bands simultaneously at 250, 360 and 520 µm 4’x8’ field of view (not fully sampled) Beam size 18”, 25”, 36” Spectrometer: µm 2.6’ circular field of view (not fully sampled) R=20->1000 (FTS)

Extragalactic Science with Herschel Note: Herschel was built to make surveys but, galaxy deep surveys are not the only kind of surveys… >1/3 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 5  1hr (obs. mode dependent, but all three bands) PACS PS imaging 3 mJy 5  1hr (two bands simultaneously) Confusion will be the main limitation of extragalactic science with Herschel

Observing with Herschel This will be a déjà-vu situation (Herschel is borrowing a lot from Spitzer) Four program categories: Garanteed Time (32%) Key programs Regular projects Open Time (68%) Key programs Regular projects 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 L+9: cycle 1 OT submitted L+12: cycle 1 OT published L+21: cycle 2 GT submitted L+24: cycle 2 GT published L+27: cycle 2 OT submitted L+30: cycle 2 OT published L+42: nominal end of mission Science timeline

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

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 or visit