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GASKAP The Galactic ASKAP Survey

GASKAP The Galactic ASKAP Survey. Dr Andrew Walsh. On behalf of the GASKAP team. ASKAP – the Australian SKA Pathfinder. 36 x 12m antennas Frequency range from 700 – 1800 MHz 30 square degree field of view Maximum baseline ~6km. ASKAP – the Australian SKA Pathfinder.

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GASKAP The Galactic ASKAP Survey

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  1. GASKAP The Galactic ASKAP Survey Dr Andrew Walsh On behalf of the GASKAP team

  2. ASKAP – the Australian SKA Pathfinder • 36 x 12m antennas • Frequency range from 700 – 1800 MHz • 30 square degree field of view • Maximum baseline ~6km GASKAP

  3. ASKAP – the Australian SKA Pathfinder • First 5 years, about 75% of time for Survey Science Projects (each at least 1500 hours) • Evolutionary Map of the Universe (EMU) • Widefield ASKAP L-Band Legacy All-Sky Blind Survey (WALLABY) • The First Large Absorption Survey in HI (FLASH) • An ASKAP Survey for Variables and Slow Transients (VAST) • Polarization Sky Survey of the Universe's Magnetism (POSSUM) • The Commensal Real-time ASKAP Fast Transients survey (CRAFT) • Deep Investigations of Neutral Gas Origins (DINGO) • The High Resolution Components of ASKAP (VLBI) • Compact Objects with ASKAP: Surveys and Timing (COAST) GASKAP –The Galactic ASKAP Survey GASKAP

  4. GASKAP – The Galactic ASKAP Survey • HI emission at 1420 MHz • OH emission 1612, 1665 and 1667 MHz • Galactic Plane: |b|<10°, 167° < l < 360° and 0° < l < 79° • (all declinations south of δ=+40°) • Entire area of Magellanic Stream and Clouds • Sensitivity typically 1K at 30” resolution and 1 km/s GASKAP

  5. GASKAP – The Galactic ASKAP Survey • HI emission at 1420 MHz • OH emission 1612, 1665 and 1667 MHz • Galactic Plane: |b|<10°, 167° < l < 360° and 0° < l < 79° • (all declinations south of δ=+40°) • Entire area of Magellanic Stream and Clouds • Sensitivity typically 1K at 30” resolution and 1 km/s GASKAP

  6. GASKAP – The Galactic ASKAP Survey • HI emission at 1420 MHz • OH emission 1612, 1665 and 1667 MHz • Galactic Plane: |b|<10°, 167° < l < 360° and 0° < l < 79° • (all declinations south of δ=+40°) • Entire area of Magellanic Stream and Clouds • Sensitivity typically 1K at 30” resolution and 1 km/s GASKAP

  7. Maser science with GASKAP • Evolved stars • Star formation • Galactic kinematics/structure • Magnetic fields • Variability • Milky Way – Magellanic Clouds comparison GASKAP

  8. Maser science with GASKAP Evolved stars • Flux limited survey of evolved stars in the Milky Way • Expect to detect thousands of OH masers • Identify rare masers associated very young (<100yr) • planetary nebulae GASKAP

  9. Maser science with GASKAP Star formation • Flux limited survey of star formation masers in the Milky Way • Expect to detect ~103 OH masers • Maser timelines • Star formation structure – disks/outflows Breen et al. (2010) maser timeline: H2O maser Class I CH3OH maser OH maser Class II CH3OH maser UCHII 104 3×104 4×104 5×104 0 2×104 Time (years) GASKAP

  10. (courtesy John Bally) Maser science with GASKAP Galactic Centre Structure (Artist’s impression byJohn Bally – private communication) Galactic Structure/Kinematics • Both evolved star and star formation masers used to trace structure and kinematics of the Milky Way and MCs • Star formation masers will be tightly linked to spiral arms – compare with Class II methanol masers from MMB • Structure of the Galactic Centre GASKAP

  11. Maser science with GASKAP Magnetic Fields • OH, as paramagnetic molecule, is ideal polarisation tool • Demonstrates Zeeman splitting (large splitting factor, milliGauss fields) • Can be used to measure magnetic fields: • larger scale with star forming OH masers • small, local fields with evolved star masers • Sensitivity to probe polarisation of weak maser features GASKAP

  12. Maser science with GASKAP Variability • OH masers are typically slowly varying over years • GASKAP will involve multi-epoch observations of bright masers over 5 years • Closely track variability in a large number of masers over these timescales GASKAP

  13. Maser science with GASKAP Milky Way – Magellanic Clouds comparison • GASKAP MC observations will increase number of known masers by two orders of magnitude • Compare the occurrence of OH masers under normal- (Galactic) and low-metallicity (MCs) circumstances GASKAP

  14. Summary • GASKAP will be coming in a few years • Observe the Galactic Plane, MCs and Magellanic Stream • Includes 1612, 1665 and 1667 MHz OH transitions • Discover thousands of new masers • Learn about: Evolved stars, Star formation, Galactic kinematics/structure, Magnetic fields, OH maser Variability, Milky Way – MCs comparison GASKAP

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