NAIC’s 2009 Program Plan & Budget Presentation December 2008 Radio Astronomy & Future Plans (Continued) Chris Salter (NAIC, Arecibo Observatory)

NAIC’s 2009 Program Plan & Budget Presentation December 2008 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. Use of an original multi-beam CLEAN. Bandwidth = 300 MHz → Faraday tomography, I p (x, y, RM). Calibration run in Oct 2008 was first scheduled observations with Mock spectrometers. Full GALFACTS survey began on November 13, (GALFACTS Pilot Survey)

NAIC’s 2009 Program Plan & Budget Presentation December 2008 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. Studies of discrete Galactic radio sources (e.g. SNRs & HII regions). Studies of high-b Galactic Loops. Foreground removal for the Planck full-Stokes CMB study. GALFA-TOG2 HI commensal project. (GALFACTS precursor imaging of the Perseus Molecular Cloud region)

NAIC’s 2009 Program Plan & Budget Presentation December 2008 A Spectral Scan of Arp 220: 1.1 – 10 GHz Arp 220 is a star-burst galaxy at a distance of 78 Mpc. It is forming stars at 100 times the rate of the Milky Way. It is the result of a collision between two galaxies now in the final stages of merging. (HST:Optical)‏ (VLA:Radio Wavlength 6cm)‏

NAIC’s 2009 Program Plan & Budget Presentation December 2008 The Spectrum of Arp 220 – Prebiotic Molecules Methanimine (CH 2 NH) observed for the first time outside of the Milky Way (where it has only been observed in one source!)‏ This is probably a maser emitter. “Bending” (v2=0) transitions of HCN detected for the very first time in the radio region. These lines are at L-, C-, C-Hi & X-band. Latest News: Detection of v2=1, J=3, HCN in Arp 220 (2645 MHz) gives a line-center optical depth,  ~ 3 at 1630 MHz.

NAIC’s 2009 Program Plan & Budget Presentation December 2008 The Spectrum of Arp 220 – OH & Other Lines OH Absorption (6 cm) ‏ OH Absorption (5 cm) ‏ OH Absorption (4 cm)‏ 18 OH or Formic Acid? (18 cm)‏CH emission triplet (λ9 cm) Co-added Hydrogen Recombination Lines (H119α → H127α). Peak Intensity ≈ 600 μJy/beam; rms noise ≈ 50 μJy/beam.

NAIC’s 2009 Program Plan & Budget Presentation December 2008 Is Arp 220 Unique? -- NO! IC 860

NAIC’s 2009 Program Plan & Budget Presentation December 2008 How to Make Spectral Scans Arecibo 305-m Telescope Covers 1.1 – 10 GHz via 6 receivers WAPP spectrometer Will analyze 800-MHz bandwidth at a time Coming soon: A single-pixel option for the new Mock spectrometers that can cover a 1-GHz (eventually 2-GHz) band with about 0.35 kms -1 resolution. H109α RRL in NGC 3628

NAIC’s 2009 Program Plan & Budget Presentation December 2008 Arecibo VLBI Highlights Continued High Sensitivity Array (HSA) operations. Continued EVN and Global Array operations Ultra-wideband VLBI with GBT at 4 Gbit/sec data rate. First regular eVLBI science runs at 128 Mbit/sec. Successful eVLBI operations at 512 Mbit/sec. Participation in first four-continent eVLBI array. + +

NAIC’s 2009 Program Plan & Budget Presentation December 2008 eVLBI at 512-Mbit/sec First trans-Atlantic eVLBI fringes at a data rate of 512 Mbits/sec on 9 September Arecibo Fringes with Participating Telescopes

NAIC’s 2009 Program Plan & Budget Presentation December 2008 Ultra-Wideband VLBI (UVLBI) The ultra-sensitive Arecibo-GBT baseline was used to search for the anticipated weak central images in 8 gravitational-lens systems. 2 × Mk5B VLBI recorders and a digital backend were loaned by Haystack Observatory allowing 4-Gbit/sec data rates. In a 10-sec integration on the Ar-Gb baseline, a signal-to-noise ratio of 1700:1 was achieved on a 122 mJy compact source. The noise level is 230/√T(sec) μJy/beam. This is the “most sensitive radio interferometry in history!”

NAIC’s 2009 Program Plan & Budget Presentation December 2008 Expected VLBI Developments in 2009 VLBI equipment upgrade to a digital backend and Mk5B/C recorder/s will allow regular recording at 2-4 times the present data rate of 1 Gbits/sec. Exploitation of 512-Mbit/sec eVLBI for regular science runs (e.g. ToO, rapid response science). Also removes the complications of disc recording. Exploration of ways to obtain a high “round-the-clock” data rate, (presently 512 Mbit/sec 00 hr < AST < 06 hr, and 128 Mbit/sec at other times.) To monitor progress towards the next generation of Space VLBI (i.e. VSOP2 (at 8 GHz & Radioastron at 327 MHz, 1.6 & 5-GHz) Acquisition of a small auxiliary dish to increase even further the efficiency of VLBI phase-referencing observations. This would also be used for educational purposes.

NAIC’s 2009 Program Plan & Budget Presentation December 2008 eVLBI Advantages No need for disks/tapes. Speed at which results are obtained. Target of Opportunity and Rapid Response Science. Real-time monitor of Station reliability. Reduced manpower at VLBI station. No longer observing blind. Disadvantages Fear of single point failure. No multi-pass correlation. Loss of low internet bandwidth stations. Presently lower max bit rate than disks. Capital and recurring costs of links.