The Herschel Space Observatory

Whee!

James Di Francesco Herzberg Institute of Astrophysics

1738-1822

What is Herschel?!

• 3.5 m diameter space telescope • covers ~57 - 670 m m • to be launched by ESA in 2008 • 4th ESA “cornerstone” missions from Horizon 2000 plan

Mirror Assembly Payload Module Service Module Sunshield/shade Herschel Space Observatory

Why go into space?

Whee!

transparent

Why go into space?

submillimetre wavelengths 350 m m 1 2 4 5 8 10

opaque

9 mm longer wavelength shorter wavelength No atmospheric absorption!!

Herschel Primary Science Goals

• The cool universe: formation of galaxies and stars, ISM physics/chemistry, solar system objects • Herschel’s large aperture, low background and no atmospheric attenuation = high sensitivity

Herschel in Context: the Past

IRAS

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

ISO

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

KAO

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

Herschel in Context: the Present

JCMT

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

Spitzer

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

ASTRO F “Akari”

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

Herschel Factoids

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

Herschel Science Team at ESTEC on 2006 Feb 1 Spacecraft in structural & thermal test configuration Flight cryostat & parts of flight service module and sunshade installed Whee!

Herschel located in large Lissajous orbit around L2

Herschel Instruments

•

PACS

(

Photodetector Array Camera and Spectrometer

) •

SPIRE

(

Spectral and Photometric Imaging REceiver

) •

HIFI

(

Heterodyne Instrument for the Far-Infrared

) HIFI SPIRE PACS (EQMs)

Herschel Instruments

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

PACS

: 1.7’ x 3.5’ FOV at 75/110 m m and 170 m m

SPIRE

: 4’ x 8’ FOV at 250, 363 and 517 m m - sensitivity: ~ 1 mJy - 1 s - 1 hour (confusion!) - no chopping! (no spatial filtering of emission) angular resolution: ~15” x ( l /250 m m) PACS SPIRE

PACS

Herschel Instruments

• Spectroscopy: 57 - 670 m m range, R = 20 - 10 7 -

PACS

: (

grating

) 0.8’ FOV at 57 - 210 m m, R = 1500 - 4000, 5 x 5 spatial x 16 spectral pixels

SPIRE

: (

FTS

) 2.6’ FOV at 200 - 670 m m, R = 20 - 100

HIFI

: (

heterodyne

) 1-pixel FOV at 157 - 212 m m and 240 - 625 m m (no gaps), 4000 channels, R = 10 7 SPIRE HIFI

CMB

Confusion Limitations

•

Photometric Confusion:

exgal bkgrd inter gal’tic dust inter stellar dust Zod iacal dust - extragalactic confusion: 1 source / 20 beams - interstellar dust: cirrus w. powerlaw fluctuations - both improve w. instrumental resolution - Herschel Confusion Noise Model made by scaling COBE/ISO data, etc. to PACS/SPIRE bands - determining actual confusion will be major PV activity

Confusion Limitations

•

Spectroscopic Confusion

:

Schilke et al. (2001)

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

Herschel Timeline: Telescope

•

2008 August

- LAUNCH • travel to L2, cooldown • commissioning & performance verification • science demonstration + workshop • routine science operations (36 months+): } 6 mos.

- ~1000 days of available time (

2009-2011

) - ~1/3 share is Guaranteed Time (GT) to instrument teams - ~2/3 share is Open Time (OT) to world community • three “Calls for Proposals” (Cycles) foreseen: - one for Key Projects (>100 hrs), GT & OT - two for regular programs, GT & OT - in every cycle, GT before OT observations

Herschel Timeline: Data

• issue AO

as late as possible

, to maximize timeliness of scientific programmes and knowledge of instruments •

2007 Feb 1

: AO for KP proposals issued •

2007 Apr 5

: deadline for GT KP proposals •

2007 Jul 5

: selection/announcement of GT KP projects •

2007 Nov 1

: deadline for OT KP proposals •

2008 Feb 28

: selection/announcement of OT KP projects •

2008 Feb 28

: AO for regular GT proposals •

2008 Apr 3

: deadline for GT1 proposals •

2008 Jun 5

: selection/announcement for GT1 projects •

2008 August

: LAUNCH

Space Astronomy Proposals

• given limited time (and maybe the promise of extra $$$), space astronomy observing time is often

heavily

oversubscribed (e.g., HST ~ 10!) • also, relatively few proposal opportunities available during lifetime of any given satellite… • need to have the highest quality proposals possible, with very little room for largesse (in words or in time!) Google image search for “working hard”

Herschel Pre-Observations

Google image search for “waiting” • space observations require careful planning and program • optimization (mission costs ~1o 6 euros/day!) use “Astronomical Observing Templates” (AOTs) to script a series of “Astronomical Observing Requests” (AORs) to execute a program, minimize overheads • For this, Herschel will use HSPOT, a variant of the Spitzer Observing Tool (SPOT): extremely easy and fun to use!

Herschel Post-Observations

• data reduced using single, coherent package: HCSS-DP • Java-based, platform independent - no licences to buy • toolbox to aid interactive analysis (IA) of data • generation of standard data products and relevant quality information (SPG & QC pipelines) • up to GT groups to provide extra tools • extensive, online & context sensitive documentation • data will be in FITS format and VO-compliant Google image search for “data reduction”

Summary

• Herschel will probe a relatively unexplored regime of the EM spectrum at high sensitivities • data will be very complementary to JCMT, ALMA • ~2/3 observing time is available to the world community, 2009-2011 • For more info see

http://www.rssd.esa.int/herschel

Whee!

Whee!

The end???

Whee!