G-ALFA Continuum Transit Survey GALFACTS E. Momjian Prepared by A.R. Taylor for the GALFA Continuum Consortium
GALFA Continuum Consortium Christy Bredeson Jo-Anne Brown Mike Davis Avinash Deshpande Tyler Foster Bryan Gaensler Tapasi Ghosh JinLin Han Marijke Haverkorn Carl Heiles Gilles Joncas Charles Kerton Paddy Leahy Tom Landecker Paddy Leahy Emmanuel Momjian Chris Salter Russ Taylor University of Calgary University of Calgary SETI institute NAIC Dominion Radio Astrophysical Observatory Harvard University NAIC Beijing Astronomical Observatory Harvard University UC Berkeley Universite Laval Iowa State University Jodrell Bank Observatory Dominion Radio Astrophysical Observatory Jodrell Bank Observatory NAIC NAIC University of Calgary *New members are welcome, contact Russ Taylor.
GALFACTS Spectro-polarimetric survey of entire Arecibo Sky ν = 300 MHz 1024 channels σ ~ 100 µjy Measuring the Galactic magnetic field and its role in the Galaxy Image the diffuse polarization in the Galaxy and the effects of the Faraday Screen Study structure and processes of the magneto-ionic ISM. Molecular cloud formation and star formation. Energization of the disk; acceleration and confinement of energetic particles. Energy and mass flow between the disk, halo, and the IGM. RM image of both diffuse emission and compact background radio source population down to polarized intensity of ~500 µjy Structure of the Galactic magnetic field from the disk to the pole. Generation and evolution of the Galactic magnetic field. Scientific pathfinder to SKA Cosmic Magnetism Key Science
DRAO Northern Sky Polarization Survey K Angular resolution 36, frequency 1.4 GHz. Polarization structure over the entire sky.
Polarisation structure from the Galactic Faraday Screen K Polarized Intensity: CGPS DRAO Synthesis Telescope only Resolution 1, frequency 1.4 GHz. Polarization angle structure from change in RM with line-of-sight Ψ = 2 RM λ RM = 0.81 n e B dl
A Hot Interstellar Medium (HIM) Bubble K Polarized Intensity: DRAO ST + Effelsberg + DRAO 26m Resolution 1, frequency 1.4 GHz. Because emission is diffuse, interferometer only provides small part of the picture. Best imaged with large single-dish telescopes
RMs of Background Sources ~1200 extragalactic sources have known RM ~ 1 RM per 30 deg 2 Recent interferometric surveys (CGPS & SGPS) yield RM to background sources in the Plane for ~1 source per deg 2 Canadian Galactic Plane Survey (Brown et al 2003, 2004)
Sky Density of RMs of Compact Radio Sources total intensity linear polarized intensity CGPS θ = 60 ~1 source per sq deg. ~ 1000 RMs GALFACTS θ = 30 ~ 4 sources per sq deg ~ 40,000 RMs SKA log N log PI (Beck & Gaensler 2004)
GALFACTS GALFACTS CGPS GALFACTS GALFACTS coverage complements the Interferometric surveys in the plane provides complete coverage from the galactic equator to the pole
GALFACTS: Precursor Observations Pilot Study Region 1 x 15 region observed with Effelsberg Mid-latitude Polarization survey
Precursor Observations of Pilot Region 1. Single-feed L-band Wide observations April-May 2005 (4x100 MHz). 2. ALFA Precursor observations December 2005 (100 MHz). Goals: Test the observing technique Fast meridian scan at 2.0 deg/min. 25 Hz pulsed cal signal injected continuously. 1 ms sample time, RFI detection and excision. Develop GALFACTS data processing pipeline.
Data Processing Pipeline
L-band wide pilot study results Arecibo Stokes U ( ν = 100 MHz, ν = 1170 MHz) Bonn 1408 MHz Effelsberg polarized intensity Arecibo Stokes I Effelsberg Stokes I
Project Timeline January 2005 - ALFA precursor observations completed April 2005 Version 1 Data processing pipeline in place ALFA precursor observations processed June 2005 Full GALFACTS proposal submitted to NAIC Fall 2005 300 MHz pulsar spectrometer complete GALFACTS observations begin For more information: www.ras.ucalgary.ca/galfacts