AUSAC Meeting · March 9 − 10, 2008

Radio Astronomy -- Other Than ALFA Surveys

Chris Salter (NAIC/Arecibo Observatory)

430-MHz Arecibo + DRAO-ST image of a region of the Perseus-Pisces Supercluster.

(Courtesy: Phil Kronberg)

AUSAC Meeting · March 9 − 10, 2008

The Rules of the Game• Pre-Nov 2006: -- 50% of R.A. telescope time for non ALFA-

survey astronomy (~2400 hr per yr). -- Rx available: 327, 430 & 610 MHz; LBW,

SBW, SBH, CB, CBH & XB. • Post-Nov 2006: -- 20% of R.A. telescope time for non ALFA-

survey astronomy (~750 hr per yr). -- Rx available: 327 & 430 MHz; LBW, CB & XB; (plus SBW, SBH & CBH on

“campaign” basis).

AUSAC Meeting · March 9 − 10, 2008

PSR J1903+0327 – Confirming its High Mass

• PSR Period = 2.15 ms

• Binary Period = 95 day

• Orbital Eccentricity = 0.44

• PSR mass = 1.67±0.01Mo → implications for EOS of cold ultra-dense matter.

J1903+0327

• Constraints on mass based on GBT and Ar timing.

• “Classical” contribution to advance of periastron is not large.

• J1903+0327 is more massive than any other NS with a precise mass determination.

• The J1903+0327 mass excludes the “softest” EOSs.

• Companion is likely to be a massive white dwarf or main sequence star.

(Courtesy: Paulo Freire)

AUSAC Meeting · March 9 − 10, 2008

Red Dwarf “Pulsars” – TVLM 513

• Arecibo provides the wide bandwidth and high spectral resolution not available with the VLA → dynamic spectra of the pulses from TVLM 513.

• Pulses resolved in both time and frequency → Brightness temperature > 1015 K for this electron cyclotron maser emission.

• Radio emission occurs at electron cyclotron frequency → magnetic field strength of kiloGauss.

• HSA (including Arecibo) used for VLBI follow-up observations.

AUSAC Meeting · March 9 − 10, 2008

The Cosmic 3He Abundance(PI: Tom Bania)

• 3He measurements can be used to test the theory of stellar nucleo-synthesis, put limits on models of Galactic chemical evolution and constrain Big-Bang nucleo-synthesis.

• Mass loss from PNe should be substantially enriched in 3He, and its abundance is an important test of stellar evolution theory.

• 3He+ has a hyperfine transition at 8665 MHz, which is detected in a composite Arecibo spectrum for NGC6210 and 6891.

• Find Arecibo X-band baselines are much better than those at L-band.

AUSAC Meeting · March 9 − 10, 2008

HI Forbidden-Velocity Wings

LDS

b=−0.5°

HVC 004-6: • 2004-6: Arecibo (LBW and ALFA) + GBT observations of 22 FVWs.

• 12-13 show shell-type structure; “missing” SNRs?

• 9-10 show cloud-type structure; halo clouds or HVCs?

(Courtesy: Ji-hyun Kang)

AUSAC Meeting · March 9 − 10, 2008

High-Resn HI Image of Smith’s Cloud • GBT image has HPBW = 9‘

• Arecibo ALFA image has HPBW = 3.5‘

• Smith’s Cloud is an HVC plunging into the Galaxy and displaying signs of interaction

• Arecibo images show evidence for hydrodynamic phenomena

• Low-velocity gas (red) appears to wrap around the Cloud, interpreted as gas stripped from the Cloud and decellerated by Milky Way halo gas

GBT

ALFA

(Courtesy: Jay Lockman)

AUSAC Meeting · March 9 − 10, 2008

The Molecular Spectra of ULIRGs

HCN v2=1, J=3 transition

Arp 220

CH triplet (λ9 cm)

Co-added H119α-H127α (λ9 cm) rms noise = 50 μJy/bm

IC 860 Zw 049.057

CH2NH

H2CO

HCN(v2=1)

Excited OH(main line)

AUSAC Meeting · March 9 − 10, 2008

Zeeman Effect in ULIRG Megamasers

• Many OH megamasers in ULIRGs show Zeeman splitting of individual components yielding typical line-of-sight magnetic fields of 0.3-18 mGauss.

• Following-up their initial detection of this phenomenon for ULIRGS, the P.I.’s are now making a Zeeman survey all suitable ULIRG OHMs in the Arecibo sky.

• Linear polarization of the OHM in Arp 220 yields a Rotation Measure.

•To resolve the Zeeman components spatially, VLBI has been made using the HSA (including Arecibo) allowing investigation of the origins of the magnetic fields.

(PI’s: Tim Robishaw & Carl Heiles)

AUSAC Meeting · March 9 − 10, 2008

An H2O Megamaser at z = 2.64(PI’s: Paola Castangia & Violetta Impellizzeri)

• MG J0414+0534 is a gravitationally lensed QSO at z = 2.64.

• H2O megamaser emission detected from it at Ef & VLA. Line is blueshifted relative to the QSO by 300 kms-1.

• Being monitored at Ar for variability of line and continuum and to search for redshifted components. If such components are found indicates a “disk maser” rather than a “jet maser”.

• After first 4 sessions, line profile appears very stable. No conclusive evidence yet for redshifted components.