Contemporary mmFIR Instruments and ALMA

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• Contemporary mm/FIR Instruments and ALMA
• Caltech Submillimeter Observatory
• and HIFI (Herschel)
• Darek Lis
• California Institute of Technology
• College Park, May 14, 2004

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Herschel Space Observatory

• ESA cornerstone mission first space facility to
  completely cover the 60670 µm spectral range
• Telescope 3.5 m Ø, passively cooled to 80 K
• Orbit Lissajous around L2 very stable and low
  background
• Larger telescope than other missions (IRAS, ISO,
  SWAS, Spitzer, Astro-F,)
• Colder aperture, better site, more observing
  time than balloon and airborne instruments (1000
  SOFIA flights/year)
• Lifetime gt3 years Ariane 5 2/15/2007
• Three cryogenically cooled instruments, PACS,
  SPIRE (bolometers), and HIFI (heterodyne)

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HIFI Top-Level Requirements
Sensitivity

• Frequency coverage
• Bands 15 (SIS) 4801250 GHz (625240 ?m)
• Band 6 (HEB) 14101910 GHz (212157 ?m)
• Near-quantum noise limit sensitivity (goal
  lt3h?/k)
• Instantaneous IF bandwidth (in 2 polarizations)
  4 GHz

• Frequency Resolution 1 MHz (WBS), 140 kHz / 280
  kHz (HRS)
• Calibration accuracy 10 baseline, 3 goal

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Who are involved?

• HIFI Principal Investigator Thijs de Graauw
• Three Co-Principal Investigators Tom Phillips
  (USA), Jürgen Stutzki (D), Emmanuel Caux (F)
• Dedicated Project Scientist Xander Tielens
• About 100 astronomical Co-Investigators
• Over 10 countries and 22 institutions involved in
  hardware development

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The Heterodyne Consortium
SIRONI
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HIFI Core ScienceLife Cycle of Gas and Dust

• ISM in Galaxies
• Normal galaxies
• Physical properties of star-forming ISM

• ISM in the Milky Way
• Structure
• Dynamics (pressure)
• Composition (gradients)

• Dense cores and star-formation
• Dynamics
• Role of Water
• Disks

• Solar System
• Water in Giant Planets
• Comets
• Chemistry
• Martian atmosphere

• Late stages of stellar evolution
• Winds
• Shells
• Asymmetries
• Composition

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HIFI ? Water
SWAS Neufeld et al. (2000)
ISO/LWS W Hya, Barlow et al. (1996)

• ISO high-energy water lines (warm ISM), low
  spectral resolution
• SWAS low-energy lines, high spectral resolution,
  but low spatial resolution

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The HIFI Advantage

• High resolving power
• High sensitivity
• Wide frequency coverage
• Small beam

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The Water Universe

• Half of HIFI water lines are in Band 6
• Back-bone lines
• Probe T200700K water
• OH and H3O for detailed investigation of water
  chemistry

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HIFI ? Unbiased Spectral Line Surveys

• Spectral surveys give an unbiased inventory of
  almost all constituents of the interstellar gas
• Several 1000s of lines are expected in sources
  like Orion-IRc2, Sgr-B2 and IRC10 216
• Other sources are expected to show (much) fewer
  lines, due to excitation, chemistry and
  beam-filling
• Improved pointing, relative calibration, sideband
  ratio compared to ground based surveys

CSO Spectrum of Orion 8 nights HIFI expected
less than 1 hour Total HIFI range in 12 hours
Schilke et al. (2001)
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HIFI and ALMA

• HIFI science unique the only opportunity to
  explore the full submm/FIR spectral range in the
  foreseeable future
• Detailed information about source structure
  (morphology, excitation conditions, kinematics)
  required to properly analyze HIFI data
• Need complementary data from ground based
  facilities, such as ALMA

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CSO Current Status and Future Upgrades

• New surface control system (50 improvement in
  aperture efficiency at 350 µm)
• Two new bolometer cameras, SHARC II and BOLOCAM
• 48 GHz IF upgrade under way
• 345 GHz 4-channel, dual polarization,
  cross-correlating Rx under development
• Z-spec (low-resolution grating spectrometer
  200300 GHz instantaneous coverage) under
  development

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CSO Bolometer Cameras

• SHARCII 12?32 pixels 360 mK pop-up bolometers
  (Goddard) 350 µm 9?? FWHM best weather NEFD 1
  Jys½

• BOLOCAM 144 spider-web bolometers (JPL) 1.1 and
  2.1 mm 30?? FWHM at 1.1 mm best weather NEFD 68
  mJys½

AC biased detectors chopping not required
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SHARC II Science
Houde et al. (2003) Dowell et al. (in prep
rms 5mJy)
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Antennae (NGC 4038-9)
Color image 15 µm, Mirabel et al.
(1998) Contours CO 1?0, Wilson et al. (2000)
Dowell et al. (in prep rms 20mJy)
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Lockman Hole East
A. Kovacs thesis
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BOLOCAM Science
M. Enoch thesis

• Perseus/Serpens wide-field mapping (Spitzer
  Legacy c2d Program)
• Lockman Hole 0.1 sq. deg., rms 1 mJy, a dozen
  candidate sources

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Progress in Bolometer Technology

• Transition to filled arrays (FOV considerations)
• Expect tremendous increase in mapping speed

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Heterodyne Instrumentation Upgrade

• Achieved optimum per-pixel sensitivity
• Increase in bandwidth

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CSO Sidecab Instrumentation

• 230, 350, 460, and 650 GHz broadband balanced
  mixers
• Continuous frequency coverage 180730 GHz
• Tunerless, twin SIS junction mixer design
• Dual frequency operation
• Junctions fabricated at JPL
• 48 GHz InP based low-noise amplifiers

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Galaxy Rx

• 4 channel, dual polarization, continuous
  comparison Rx
• Tunerless mixers (not balanced)
• 48 GHz IF
• Expected sensitivity gain a factor of 5 compared
  to the existing tuned waveguide Rx
• 100 µK (100MHz) in 8 hours Integration

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Spectroscopy at the CSO

• Deuterium fractionation (ND3, D2S, H2D, D2H)
• Line surveys (sideband deconvolution techniques
  for HIFI)

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Atacama Telescope

• CSO capabilities may be transferred in the future
  to the 25-m Atacama Telescope
• MOU between Cornell and Caltech for a two-year
  feasibility study signed
• Science working groups established (main drivers
  cosmology, wide-field continuum imaging, 200 µm
  window)
• Site evaluation starts later this month
• Long-term goal is to develop the 25-m, including
  the instrumentation

www.astro.cornell.edu/research/projects/atacama