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Chris Salter (NAIC – Arecibo)

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GALFA & GALFACTS. GALFA-HI and GALFACTS (Courtesy: Steven Gibson). Chris Salter (NAIC – Arecibo). GALFA Sub-Consortia. H I Line ( GALFA-H I ) Continuum ( GALFA-CON = GALFACTS ) Radio Recombination Lines ( GALFA-RRL )

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slide1
NAIC-AUSAC Meeting April 19 & 20, 2010

GALFA & GALFACTS

GALFA-HI and GALFACTS

(Courtesy: Steven Gibson)

Chris Salter (NAIC – Arecibo)

galfa sub consortia
NAIC-AUSAC Meeting April 19 & 20, 2010GALFA Sub-Consortia
  • H I Line (GALFA-HI)
  • 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.
slide3
NAIC-AUSAC Meeting April 19 & 20, 2010

RRL Galactic-Plane Survey

(PI: Yervant Terzian)

  • Galactic Structure
  • Chemical Abundances
  • Warm Diffuse ISM
  • HII Regions
  • Survey for |b| < 5o
  • Integration time of 300s
  • 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)

galfacts galfa continuum transit survey
NAIC-AUSAC Meeting April 19 & 20, 2010GALFACTS (GALFA Continuum Transit Survey)

(GALFACTS Pilot 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, Ip(x, y, RM).
  • Use “winking cal” for best possible calibration.
  • Use of an original multi-beam CLEAN.
  • Calibration run in Oct 2008 was first scheduled observations with Mock spectrometers.
  • First GALFACTS region (1h

Now also observed at 327 MHz (Raja et al.) to provide finer resolution in RM for Faraday Tomography)

slide5
NAIC-AUSAC Meeting April 19 & 20, 2010

Mapping Technique: ZA Nodding + AZ Wagging

  • 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

Tracks after several passes

ALFA beams

These are “woven” together to optimize zerolevels.

galfacts continued
NAIC-AUSAC Meeting April 19 & 20, 2010GALFACTS (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.

(GALFACTS precursor imaging of the

Perseus Molecular Cloud region)

slide7
NAIC-AUSAC Meeting April 19 & 20, 2010

GALFA-H I Observations

GALFA-HI Pointing Record as of 2009 February 26

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 projects
NAIC-AUSAC Meeting April 19 & 20, 2010GALFA H I Projects

(Trms ~ 0.25 K)‏

PRECURSOR

PERSEUS

I-GALFA/ZOA/

GALFACTS2

a1943

HALO

CLOUDS

MBW/ZOA

a2174/2294

DISK-

HALO

a2056/2051

a2186/2144/2390

OUTER

HALO

HIGH-LAT

TURBULENCE

a2034

a2060

WINGS

TAURUS

SHELL

a2055

a2004

a2172

a2221

a2050

a2172

a2011

a2187

a2222

a2011

a2032

HIGH-LAT

CLOUDS

WATER

FALL

a2147

TRUE

FIL

TIP MAG

STREAM

GEM

OB1

a2220

COLD

CLOUD

a2130/2124

a2010/2059

a2048/2059

GALFACTS/TOGS2

ALFALFA/TOGS1

AGES/TOGS1

(Trms ~ 0.35 K)‏

(Trms ~ 0.15 K)‏

(Trms ~ 0.04 K)‏

slide9
NAIC-AUSAC Meeting April 19 & 20, 2010

I-GALFA Survey: 2008-9

I-GALFA Plane H I Survey

VGPS

SGPS

CGPS

10 x IGPS sensitivity,

4 x velocity resolution

i galfa low b galactic center quadrant
NAIC-AUSAC Meeting April 19 & 20, 2010I-GALFA (low-b Galactic Center Quadrant)

(PI’s: Steven Gibson & Bon Chul Koo)

Cold HI Absorption in Molecular Clouds

Cold HI Emission at Higher Latitudes

  • Over 50% completed in 2008
  • Full completion expected during 2009
  • Commensal with GALFACTS2

Disc-Halo Interface

hi near globular cluster pal 4
NAIC-AUSAC Meeting April 19 & 20, 2010HI near Globular Cluster, Pal 4

(PI: Jacco van Loon)

  • Earlier LBW study detected HI in metal-poor cluster, M15 (van Loon et al, 2006).
  • New stringent HI upper limits placed on clusters M3, NGC 5466 & Pal 13.
  • Pal 4 is the 2nd most distant known globular cluster (D = 109 kpc).
  • Large HI HVC discovered near Pal 4. Is it coincidence, gas stripped from the cluster by interaction with halo gas, or could both be situated in a 108 Mo dark halo?
an ivc towards abell 1367
NAIC-AUSAC Meeting April 19 & 20, 2010An IVC Towards Abell 1367

(PI: Kevin Douglas)

  • Commensal GALFA-HI observations with EALFA-AGES of 10 fields.
  • The Abell 1367 field is at b ≈ 70°−75°, and reveals possibly cometary IVCs.
  • Brightness temperatures of the features are only 1K or less!
the three little pigs and a friend
NAIC-AUSAC Meeting April 19 & 20, 2010The 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 TB ≈ 10K.
  • Upper limits on OH emission from Arecibo.
galfa summary
NAIC-AUSAC Meeting April 19 & 20, 2010GALFA Summary
  • Small GALFA-H I projects completed
  • 3 Sub-Consortia (GALFA-H I, -CON, -RRL)
  • TOGS1&2 in progress; data analysis on-going
  • I-GALFA and GALFACTS in progress
  • GALFA-RRL/ZOA/PALFA starting soon
  • All final GALFA datasets will be on NVO
  • GALFA website:www.naic.edu/alfa/galfa
galfa h i projects1
NAIC-AUSAC Meeting April 19 & 20, 2010GALFA - H I Projects

56% Mar 17

16% Mar 17

78% Mar 17

start ASAP

start May 3

full stokes multibeam clean
NAIC-AUSAC Meeting April 19 & 20, 2010Full-Stokes Multibeam CLEAN

Stokes I

Dirty Image

Multibeam

Clean Image

(HPBW=3.5°)

(S. Guram,

MSc Thesis,

U. Calgary)

NVSS

Comparison

(HPBW=0.7°)

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