The Herschel Space Observatory

James Di FrancescoHerzberg Institute of Astrophysics

1738-1822

Whee!Whee!

What is Herschel?!What is Herschel?!

• 3.5 m diameter space3.5 m diameter space telescopetelescope

• covers ~57 - 670 covers ~57 - 670 mm

• to be launched by ESAto be launched by ESA in 2008in 2008

• 4th ESA “cornerstone”4th ESA “cornerstone” missions from Horizonmissions from Horizon 2000 plan2000 plan

Herschel Space Observatory

Mirror Assembly

Payload Module

Service Module

Sunshield/shade

Why go into space?Why go into space?

Whee!Whee!

No atmospheric absorption!!

1 2

4

5

8

10

transparent

opaquelonger wavelength shorter wavelength

submillimetre wavelengths

9 mm

350 m

Why go into space?Why go into space?

Herschel Primary Science Herschel Primary Science GoalsGoals

• The cool universe: formation of galaxies and stars,The cool universe: formation of galaxies and stars, ISM physics/chemistry, solar system objectsISM physics/chemistry, solar system objects

• Herschel’s large aperture, low background and noHerschel’s large aperture, low background and no atmospheric attenuation = high sensitivityatmospheric attenuation = high sensitivity

Herschel in Context: the PastHerschel in Context: the Past

IRASIRAS (1983); o.57 m aperture (1983); o.57 m aperture - all sky survey at 12, 25, 60, 100 - all sky survey at 12, 25, 60, 100 mm - low-res spectroscopy at 7.5 - 23 - low-res spectroscopy at 7.5 - 23 mm

ISOISO (1995-1998); o.60 m (1995-1998); o.60 m apertureaperture - photometry at 2.5 - 240 - photometry at 2.5 - 240 mm - spectroscopy at 2.4 - 197 - spectroscopy at 2.4 - 197 mm

KAOKAO (1974-1995); o.91 m aperture (1974-1995); o.91 m aperture - photometry and spectroscopy from - photometry and spectroscopy from = = ~20 ~20 m to ~500 m to ~500 m; many m; many instruments instruments

Herschel in Context: the Herschel in Context: the PresentPresent

JCMTJCMT (1987 - ?); 15 m aperture (1987 - ?); 15 m aperture - photometry at 450 & 850 - photometry at 450 & 850 m m (SCUBA2)(SCUBA2) - spectr’py at 1300, 850, 650, 450 - spectr’py at 1300, 850, 650, 450 mm

SpitzerSpitzer (2003 - 2008?); 0.85 m (2003 - 2008?); 0.85 m apertureaperture - photo’ry at 3.6, 4.5, 5.8, 8.0 - photo’ry at 3.6, 4.5, 5.8, 8.0 m m (IRAC), (IRAC), 24, 70, 160 24, 70, 160 m (MIPS)m (MIPS) - spectroscopy at 5-38 - spectroscopy at 5-38 m (IRS)m (IRS)

ASTRO-F “Akari”ASTRO-F “Akari” (2006 - ?); 0.685 m (2006 - ?); 0.685 m - 4-band all-sky survey at 50-200 - 4-band all-sky survey at 50-200 m m (FIS)(FIS) - imaging/spectr’py at 1.8-26 - imaging/spectr’py at 1.8-26 m (IRC)m (IRC)

Herschel FactoidsHerschel Factoids

• primary diameter = 3.5 m (large!)primary diameter = 3.5 m (large!)• primary material = SiC with a thinprimary material = SiC with a thin reflective Al layer + plasil layerreflective Al layer + plasil layer• primary WFE < 6%primary WFE < 6%• telescope temperature < 90 Ktelescope temperature < 90 K• telescope emissivity < 4%telescope emissivity < 4%• abs/rel pointing (68%) < 3.7” / 0.3”abs/rel pointing (68%) < 3.7” / 0.3”• science instruments = 3science instruments = 3• cryostat lifetime > 3.5 yearscryostat lifetime > 3.5 years• height / width ~ 7.5 m / 4 mheight / width ~ 7.5 m / 4 m• launch mass = 3200 kglaunch mass = 3200 kg• power ~ 1500 Wpower ~ 1500 W

cold sidecold side

hot sidehot side

Herschel Science TeamHerschel Science Teamat ESTEC on 2006 Feb 1at ESTEC on 2006 Feb 1

Spacecraft in structural &Spacecraft in structural &thermal test configurationthermal test configuration

Flight cryostat & parts of Flight cryostat & parts of flight service module andflight service module andsunshade installedsunshade installed

Whee!Whee!

Herschel located in large Lissajous orbit around L2

Herschel InstrumentsHerschel Instruments

• PACSPACS ( (Photodetector Array Camera and SpectrometerPhotodetector Array Camera and Spectrometer))

• SPIRESPIRE ( (Spectral and Photometric Imaging REceiverSpectral and Photometric Imaging REceiver))

• HIFIHIFI ( (Heterodyne Instrument for the Far-InfraredHeterodyne Instrument for the Far-Infrared))

HIFIHIFI

PACSPACS

SPIRESPIRE

(EQMs)(EQMs)

Herschel InstrumentsHerschel Instruments

• Photometry/Imaging: 6 bands at 75-500 Photometry/Imaging: 6 bands at 75-500 mm

- - PACSPACS: 1.7’ x 3.5’ FOV at 75/110 : 1.7’ x 3.5’ FOV at 75/110 m and 170 m and 170 mm - - SPIRESPIRE: 4’ x 8’ FOV at 250, 363 and 517 : 4’ x 8’ FOV at 250, 363 and 517 mm

- sensitivity: ~ 1 mJy - 1 - sensitivity: ~ 1 mJy - 1 - 1 hour (confusion!) - 1 hour (confusion!) - no chopping! (no spatial filtering of emission)- no chopping! (no spatial filtering of emission) - angular resolution: ~15” x (- angular resolution: ~15” x (/250 /250 m) m)

PACS SPIRE

Herschel InstrumentsHerschel Instruments

• Spectroscopy: 57 - 670 Spectroscopy: 57 - 670 m range, R = 20 - 10m range, R = 20 - 1077

- - PACSPACS: (: (gratinggrating) 0.8’ FOV at 57 - 210 ) 0.8’ FOV at 57 - 210 m,m, R = 1500 - 4000, 5 x 5 spatial x 16 spectral pixelsR = 1500 - 4000, 5 x 5 spatial x 16 spectral pixels - - SPIRESPIRE: (: (FTSFTS) 2.6’ FOV at 200 - 670 ) 2.6’ FOV at 200 - 670 m,m, R = 20 - 100R = 20 - 100 - - HIFIHIFI: (: (heterodyneheterodyne) 1-pixel FOV at 157 - 212 ) 1-pixel FOV at 157 - 212 m andm and 240 - 625 240 - 625 m (no gaps), 4000 channels, R = 10m (no gaps), 4000 channels, R = 1077

PACS SPIRE HIFI

Confusion LimitationsConfusion Limitations

CMBexgalbkgrd

intergal’ticdust

interstellardust

Zod-iacaldust

• Photometric Confusion:Photometric Confusion:

- extragalactic confusion: 1 source / 20 beams- extragalactic confusion: 1 source / 20 beams - interstellar dust: cirrus w. powerlaw fluctuations- interstellar dust: cirrus w. powerlaw fluctuations

- both improve w. instrumental resolution- both improve w. instrumental resolution

- Herschel Confusion Noise Model made by- Herschel Confusion Noise Model made by scaling COBE/ISO data, etc. to PACS/SPIRE bandsscaling COBE/ISO data, etc. to PACS/SPIRE bands - determining actual confusion will be major PV activity- determining actual confusion will be major PV activity

Confusion LimitationsConfusion Limitations

• Spectroscopic ConfusionSpectroscopic Confusion::

- “U” lines problematic (but not like OMC1 everywhere)- “U” lines problematic (but not like OMC1 everywhere)

Schilke et al. (2001)Schilke et al. (2001)

Herschel Timeline: TelescopeHerschel Timeline: Telescope

• 2008 August2008 August - LAUNCH - LAUNCH• travel to L2, cooldowntravel to L2, cooldown• commissioning & performance verificationcommissioning & performance verification• science demonstration + workshopscience demonstration + workshop• routine science operations (36 months+):routine science operations (36 months+):

- ~1000 days of available time (- ~1000 days of available time (2009-20112009-2011))

- ~1/3 share is Guaranteed Time (GT) to - ~1/3 share is Guaranteed Time (GT) to

instrument teamsinstrument teams

- ~2/3 share is Open Time (OT) to world - ~2/3 share is Open Time (OT) to world

communitycommunity• three “Calls for Proposals” (Cycles) foreseen:three “Calls for Proposals” (Cycles) foreseen:

- one for Key Projects (>100 hrs), GT & OT- one for Key Projects (>100 hrs), GT & OT

- two for regular programs, GT & OT- two for regular programs, GT & OT

- in every cycle, GT before OT observations- in every cycle, GT before OT observations

}6 mos.6 mos.

Herschel Timeline: DataHerschel Timeline: Data

• issue AO issue AO as late as possibleas late as possible, to maximize , to maximize

timeliness of timeliness of

scientific programmes and knowledge of scientific programmes and knowledge of

instruments instruments

• 2007 Feb 12007 Feb 1: AO for KP proposals issued: AO for KP proposals issued• 2007 Apr 52007 Apr 5: deadline for GT KP proposals: deadline for GT KP proposals• 2007 Jul 52007 Jul 5: selection/announcement of GT KP : selection/announcement of GT KP

projectsprojects• 2007 Nov 12007 Nov 1: deadline for OT KP proposals: deadline for OT KP proposals• 2008 Feb 282008 Feb 28: selection/announcement of OT KP : selection/announcement of OT KP

projectsprojects• 2008 Feb 282008 Feb 28: AO for regular GT proposals: AO for regular GT proposals• 2008 Apr 32008 Apr 3: deadline for GT1 proposals: deadline for GT1 proposals• 2008 Jun 52008 Jun 5: selection/announcement for GT1 : selection/announcement for GT1

projectsprojects• 2008 August2008 August: LAUNCH: LAUNCH

Space Astronomy ProposalsSpace Astronomy Proposals

• given limited time (and maybe the promise of given limited time (and maybe the promise of

extraextra

$$$), space astronomy observing time is often $$$), space astronomy observing time is often

heavilyheavily

oversubscribed (e.g., HST ~ 10!)oversubscribed (e.g., HST ~ 10!)• also, relatively few proposal opportunities available also, relatively few proposal opportunities available

during lifetime of any given satellite…during lifetime of any given satellite…• need to have the highest quality proposals need to have the highest quality proposals

possible, with possible, with

very little room for largesse (in words or in time!)very little room for largesse (in words or in time!)Google imageGoogle image

search for search for ““working hard”working hard”

Herschel Pre-ObservationsHerschel Pre-Observations

• space observations require careful planning and space observations require careful planning and

programprogram

optimization (mission costs ~1ooptimization (mission costs ~1o66 euros/day!) euros/day!)• use “Astronomical Observing Templates” (AOTs) use “Astronomical Observing Templates” (AOTs)

to to

script a series of “Astronomical Observing script a series of “Astronomical Observing

Requests” Requests”

(AORs) to execute a program, minimize overheads(AORs) to execute a program, minimize overheads• For this, Herschel will use HSPOT, a variant of the For this, Herschel will use HSPOT, a variant of the

SpitzerSpitzer

Observing Tool (SPOT): extremely easy and fun to Observing Tool (SPOT): extremely easy and fun to

use!use!

Google imageGoogle imagesearch for search for ““waiting”waiting”

Herschel Post-ObservationsHerschel Post-Observations• data reduced using single, coherent package: data reduced using single, coherent package:

HCSS-DP HCSS-DP • Java-based, platform independent - no licences to Java-based, platform independent - no licences to

buybuy• toolbox to aid interactive analysis (IA) of datatoolbox to aid interactive analysis (IA) of data• generation of standard data products and relevant generation of standard data products and relevant

quality quality

information (SPG & QC pipelines)information (SPG & QC pipelines)• up to GT groups to provide extra toolsup to GT groups to provide extra tools• extensive, online & context sensitive extensive, online & context sensitive

documentationdocumentation• data will be in FITS format and VO-compliantdata will be in FITS format and VO-compliant

Google imageGoogle imagesearch for search for

““data reduction”data reduction”

SummarySummary

• Herschel will probe a relatively unexplored regime Herschel will probe a relatively unexplored regime

ofof

the EM spectrum at high sensitivitiesthe EM spectrum at high sensitivities• data will be very complementary to JCMT, ALMAdata will be very complementary to JCMT, ALMA• ~2/3 observing time is available to the world ~2/3 observing time is available to the world

community,community,

2009-20112009-2011• For more info see For more info see http://www.rssd.esa.int/herschelhttp://www.rssd.esa.int/herschel

The end???The end???

Whee!Whee!Whee!Whee!

Whee!Whee!