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, Ip(x, y, RM).

• Calibration run in Oct 2008 was first scheduled observations with Mock spectrometers.

• Full GALFACTS survey began on November 13, 2008. (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 (CH2NH) 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)

18OH 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 -- 2008

+ + +

• 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 2008.

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

eVLBIAdvantages

• 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.