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NAIC-AUSAC Meeting April 19 & 20, 2010 Chris Salter (NAIC – Arecibo) GALFA & GALFACTS GALFA-HI and GALFACTS (Courtesy: Steven Gibson)
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NAIC-AUSAC Meeting April 19 & 20, 2010 GALFA Sub-Consortia H I Line (GALFA-H I ) Continuum (GALFA-CON = GALFACTS) Radio Recombination Lines (GALFA-RRL) Each GALFA sub-consortium has its own membership and internal organization. All GALFA data will be made public through the National Virtual Observatory.
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NAIC-AUSAC Meeting April 19 & 20, 2010 RRL Galactic-Plane Survey Galactic Structure Chemical Abundances Warm Diffuse ISM HII Regions Survey for |b| < 5 o Integration time of 300-600s Commensal with PALFA & ZoA projects Share a “Mock spectrometer” database with ZoA (Δv≈4 kms -1 ) Record H163α−H174α, plus He & C α-lines and H β-lines Co-add transitions to increase signal-to-noise “Leap-Frog” Pointing to provide ON/OFFs (Terzian & Lewis)
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NAIC-AUSAC Meeting April 19 & 20, 2010 GALFACTS (GALFA Continuum Transit Survey) Full-Stokes, all-Arecibo-sky, continuum survey. Employs meridian NODding scans with subsequent “multi-beam” basket- weaving to optimize zero-levels. Bandwidth = 300 MHz → Faraday tomography, I p (x, y, RM). Use “winking cal” for best possible calibration. Use of an original multi-beam CLEAN. To date, two extensive regions observed; (a) 1 h <RA<7 h ; 20°<δ<38° in Nov-Dev 2009, and, (b) 4 h <RA<10 h ; −1°<δ<17°)i in Dec 2009 and Jan 2010. Stokes I Dirty Image Multi-beam Clean Image (HPBW=3.5') NVSS Comparison (HPBW=0.7')
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NAIC-AUSAC Meeting April 19 & 20, 2010 Mapping Technique: ZA Nodding (+ AZ Wagging) Mapping Technique: ZA Nodding (+ AZ Wagging) ALFA beams Tracks after several passes These are “woven” together to optimize zerolevels. P.I.: Russ Taylor Web Page: www.ucalgary.ca/ras/GALFACTS 14400 channels over 300-MHz bandwidth with “Mock spectrometer” Brightness sensitivity: rms~100 μJy/bm Meridian scanning speed ~1.5° per sec CIMA “Smart Basket-weaving” used
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NAIC-AUSAC Meeting April 19 & 20, 2010 GALFACTS (continued) GALFACTS (continued) Catalog of Poln. Percentage, Position Angle & RM for 50,000 sources → Galactic Magnetic Field Studies. Thermal-nonthermal separation of low-b Galactic continuum emission. Provide thermal brightnesses for use by GALFA-RRL. Studies of discrete Galactic radio sources (e.g. SNRs & HII regions). Studies of high-b Galactic Loops. Foreground removal for EoR and Planck full-Stokes CMB studies. GALFA-HI TOG2 commensal project. First GALFACTS look at the Galactic Center quadrant via commensal observations with I-GALFA. Beam 5 missing from Stokes-I. Beams 5 & 6 missing from Q & U. Stokes I Stokes Q Stokes U
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WHY GALFA-HI? WHY GALFA-HI? With single-dish brightness temperature sensitivity and high spectral and angular resolution, it covers new parameter space:
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NAIC-AUSAC Meeting April 19 & 20, 2010 GALFA-HI Pointing Record as of 2008 March 14 GALSPECT has 8192 channels over 7.14 MHz → 0.18 km/s/channel, and ± 750 km/s total coverage GALFA-H I Observations GALFA-HI Pointing Record as of 2009 February 26 GALFA-HI Pointing Record as of 2010 April 4
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NAIC-AUSAC Meeting April 19 & 20, 2010 I-GALFA – The Inner Galaxy ALFA low-b HI Survey I-GALFA covers 35°≤ l ≤85°, |b| ≤10°. Observations were completed in September 2009. HPBW=3.35', T rms = 0.25 K, Δv chan = 0.18 km/s, |v lsr | < 750 km/s. (Triple) Commensal with ZOA & GALFACTS2. Prominent is the HI/continuum supershell GS 041+01+27, probably lying in the Sagittarius spiral arm. (top) I-GALFA HI image – v lsr = +27 km/s; (bottom) GALFACTS2 L-band continuum image Disc-Halo Interface
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NAIC-AUSAC Meeting April 19 & 20, 2010 TOGS/TOGS2 is commensal with GALFACTS, ALFALFA & AGES, mapping the whole Arecibo sky in HI at no overhead in observing time. Used to study, (a) Galactic structure, (b) correlation of HVC HI and dust contents, (c) HI clouds surrounding M33 attributed to M33–M31 tidal interactions, (d) HI content of Local Group dwarf galaxies, and (e) HI content of globular clusters. GALFA-TOGS/TOGS2 Wide-Area HI Survey TOGS = “Turn On GALFA Spectrometer!” HI for -5 ≤ v lsr ≤ 0 km/ s (Image includes I-GALFA data)
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NAIC-AUSAC Meeting April 19 & 20, 2010 The Three Little Pigs (and a Friend) The Three Little Pigs (and a Friend) (PI: Josh Goldston Peek) Tiny clouds found at b ≈ 85°; Δθ ≈ 1'. VLA follow-up shows condensed cores, optically-thick, with T B ≈ 10K. Arecibo measures Magnetic Field strength ~14 μG → 200 – 800 times the magnetic pressure of the WIM. Upper limits on OH emission from Arecibo.
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NAIC-AUSAC Meeting April 19 & 20, 2010 Pigs by the Drove! Ayesha Begum & Snezana Stanimirovic About 100 compact, cold clouds, isolated from Galactic emission found in a limited area of the TOGS/TOGS2 survey. Median angular size ~5', T b ~ 0.7 K, FWHM ~ 4.2 km/s, and N HI ~ 5 × 10 18 cm -2. Clouds deviate from Galactic rotation by 10 – 40 km/s, and evidence for multiphase medium and velocity gradients. If D ≤ 100 pc, then thermal pressure is order of magnitude > ISM. and size ≤ 30,000 AU suggesting short lifetimes. Could be 'spray' of transient, small, HI clouds resulting from ISM turbulence effects. If D = 1 – 3 kpc, then they would represent 'pockets' of cold HI immersed in warm/hot halo gas. Explaining their survival is then a challenge.
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HI Outflows from RS-CVn variables (eclipsing binaries with magnetically active chromospheres). -100 to -70 km/s -40 to -25 km/s
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NAIC-AUSAC Meeting April 19 & 20, 2010 GALFA Summary 3 Sub-Consortia; GALFA-H I, -CON (& -RRL) Small GALFA-H I projects completed TOGS1&2 in progress; data analysis on-going I-GALFA completed; GALFACTS ~20% complete PALFA acquiring RRL/ZOA data All final GALFA datasets will be available via NVO GALFA website: www.naic.edu/alfa/galfa
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NAIC-AUSAC Meeting April 19 & 20, 2010 Muchas Gracias
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GALFACTS (GALFA Continuum Transit Survey) GALFACTS is a full-Stokes, all-Arecibo-sky, continuum survey. It uses the Mock spectrometer, and an original multi-beam CLEAN. The GALFACTS survey began November 2008, and is about 12% complete. Studies of a) Galactic magnetic field via both point-source and foreground polarization, b) thermal/nonthermal separation of Galactic foreground, & c) SNRs, HII regions and the Galactic loops. Bandwidth = 300 MHz → Faraday tomography, I p (x, y, RM).
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NAIC-AUSAC Meeting April 19 & 20, 2010 GALFA - H I Projects 56% Mar 17 16% Mar 17 78% Mar 17 start ASAP start May 3
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Marrying NVSS and GALFA-HI will provide >1000 positions with reliable temperatures. This freezing cold cloud lies only 20 pc from the Sun—within the local bubble!
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NAIC-AUSAC Meeting April 19 & 20, 2010 CGPS VGPS SGPS I-GALFA Plane H I Survey 10 x IGPS sensitivity, 4 x velocity resolution I-GALFA Survey: 2008-9
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NAIC-AUSAC Meeting April 19 & 20, 2010 GALFA H I Projects a2186/2144/2390 a2048/2059a2010/2059 a2130/2124 a2056/2051 a2060 a2055 a2034 a1943 a2004 a2174/2294 a2221 ALFALFA/TOGS1AGES/TOGS1 GALFACTS/TOGS2 I-GALFA/ZOA/ GALFACTS2 DISK- HALO MBW/ZOA PERSEUS TAURUS HALO CLOUDS WINGS a2220 a2222a2187 a2050 a2011 a2172 a2147 a2032 TIP MAG STREAM GEM OB1 TRUE FIL SHELL HIGH-LAT CLOUDS HIGH-LAT TURBULENCE WATER FALL OUTER HALO PRECURSOR COLD CLOUD (T rms ~ 0.25 K) (T rms ~ 0.15 K)(T rms ~ 0.04 K) (T rms ~ 0.35 K)
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