Transcript Non ALFA-Survey Radio Astronomy

Radio Astronomy -- Other Than
ALFA Surveys
430-MHz Arecibo + DRAO-ST
image of a region of the PerseusPisces Supercluster.
(Courtesy: Phil Kronberg)
Chris Salter (NAIC/Arecibo Observatory)
AUSAC Meeting · March 9 − 10, 2008
The Rules of the Game
• Pre-Nov 2006:
-- 50% of R.A. telescope time for non ALFAsurvey 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 ALFAsurvey 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
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.
• 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.
(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
HVC
LDS
b=−0.5
°
• 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‘
GBT
• 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
(Courtesy: Jay Lockman)
ALFA
AUSAC Meeting · March 9 − 10, 2008
The Molecular Spectra of ULIRGs
Arp 220
Zw 049.057
IC 860
CH2NH
HCN v2=1, J=3 transition
H2CO
CH triplet (λ9 cm)
HCN
(v2=1)
Excited OH
(main line)
Co-added H119α-H127α (λ9 cm)
rms noise = 50 μJy/bm
AUSAC Meeting · March 9 − 10, 2008
Zeeman Effect in ULIRG Megamasers
(PI’s: Tim Robishaw & Carl Heiles)
• 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.
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.
AUSAC Meeting · March 9 − 10, 2008