AUSAC Meeting April 19 − 20, 2010 Radio Astronomy -- Other Than ALFA Surveys Chris Salter...

AUSAC Meeting April 19 − 20, 2010

Radio Astronomy -- Other Than Radio Astronomy -- Other Than ALFA SurveysALFA Surveys

Chris Salter (NAIC/Arecibo Observatory)

FVW39.0+4.0: An HI Forbidden Velocity Wing,

Blue = +80 – +95 km/s

Green = +95 – +110 km/s

Red = +110 – +135 km/s

Stars = Early-type stars in field

Triangles = Pulsars

(Courtesy: Ji-hyun Kang )


The Official Rules of the GameThe Official Rules of the Game

• Post-Nov 2006: -- 20% of R.A. telescope time for non ALFA-

survey astronomy (~750 hr per yr).

-- Rxs available: 327, 430 & 750 MHz, ALFA, LBW, SBW, CB & XB; (plus SBH &

CBH on a “campaign” basis).


• Arecibo pulsar, J2021+3651 is found to be one of the strongest γ-ray emitters by Fermi/GLAST.

• Of 9 new γ-ray pulsars in the Arecibo sky from Fermi/GLAST, J1907+0602 is found to be a radio pulsar (P=0.10664 s). With S

1.4 GHz= 3 μJy, and a distance ~ 3 kpc, it is

the second least luminous pulsar known!

Radio and Radio and γ-Ray γ-Ray PulsarsPulsarsArecibo timing of 'unidentified' Fermi source, J2214+3002, has permitted the detection of the object as a γ-ray pulsar.

Fermi pulsar, J2017+0603, has been observed several times at Arecibo, and found to have a 'super-sharp' pulse profile. As it is likely a MSP-WD binary, it is a good NANOGrav candidate.


Four-Frequency High Precision Timing of a Msec PulsarFour-Frequency High Precision Timing of a Msec PulsarThe detection of gravitational

waves with pulsars will requires high timing precision: effects at 10 ns level can limit the sensitivity to gravitational waves.

ISM acts like warped glass, distorting the trajectory of the propagating radio waves (tube). As the volume of interstellar space changes, the tube wanders → arrival time variations.

Goals of project: Identify and mitigate the effect of variability in the ISM (interstellar weather) in precision pulsar timing observations.

Radio waves travel through banana-shaped tube

Tube size

PulsarEarth

Solar System Barycentre

Tube offset from direct line-of-sight

Target: PSR J1713+0747, the most stable millisecond pulsar in the Arecibo sky.

Observations: 327 MHz, 430 MHz, L and S bands; 20 transits over 6 months.

Data recorded simultaneously for timing (ASP, high time resolution), for ISM analysis (WAPP, higher frequency resolution), and a VLBI baseband recorder (Mark5A).


L-band observations,systematic trends (associated with ISM?)

S-band observations, lower timing precision due to lower flux.

Combine all TOAs to form “grand” arrival time at this epoch

~ 2 hours

~1

microsec

430 MHz 327 MHz

Key Analysis: Connect residual ToA (top) and pulsar dynamic spectra (right) and determine if the dynamic spectra encode ISM delays?

Ph.D. Thesis:Ryan Shannon


Apparent > Apparent > cc Wave Propagation in the ISM Wave Propagation in the ISM

The group velocity of the ISM is > c near the HI resonance line due to “anomalous dispersion”.

The plot above shows the expected absorption and delay spectra after propagation though a cloud of HI in the ISM with T

S= 100 K, tau = 1.

HI Emission Spectrum

PSR Absorption Spectrum

PSR Delay Spectrum

Delay Spectra for 3 Consecutive Days

Potential tool for studying the HI properties of the ISM. (Note: It does NOT violate Special Relativity!)


HI Forbidden-Velocity Wings

LDS

b=−0.5°

HVC 004-6: •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?

FVW's 173.0+1.5 & 173.0+0.0: Red = +45 – +35 km/s, Green = +35 – +25 km/s, Blue = +25 – +15 km/s. The HI emission coincides with a weak continuum shell. FVW G40.0+0.5: Red = -100 – -90 km/s,

Green = -90 – -80 km/s, Blue = -80 – -70 km/s.


Zeeman Effect in ULIRG Megamasers

• The P.I.’s have been granted 450 hr to make a Zeeman survey all suitable ULIRG OHMs in the Arecibo sky.

• Many OH megamasers in ULIRGs show Zeeman splitting of individual components yielding typical line-of-sight magnetic fields of 0.3-18 mG. Minimum energy and equipartition suggest ULIRG magnetic fields of 1 mG < B < 10 mG.

• B is similar to the values in Galactic OH masers, suggesting conditions of massive star formation are similar to those in the Milky Way.

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


Molecular Lines in GalaxiesMolecular Lines in Galaxies

H2O maser in host galaxy of

QSO J0414+0534 (z=2.64) monitored at 6-week intervals.

Top Formaldehyde Absorption and (bottom) excited-line OH maser emission in LIRG, NGC 660

CH2NH

H2CO

HCN (v2=1)

Excited OH (main line)

Molecules in Zw 049.057


700 700 – 800 MHz Gallery– 800 MHz Gallery

CH main line at CH main line at 724 MHz in W51724 MHz in W51

HI absorption in the HI absorption in the host galaxy of CTA 21 host galaxy of CTA 21 against the continuum against the continuum emission of the central emission of the central quasarquasar

Observed at Arecibo on Observed at Arecibo on 20 & 21 September 200920 & 21 September 2009 Redshift,Redshift, z z = 0.906 = 0.906 CTA 21 is seen at 46% CTA 21 is seen at 46% of the present age of the of the present age of the Universe Universe

M5A

M13A

M13C

M15A

M15B

M15C

Globular Cluster Pulsar ObservationsGlobular Cluster Pulsar Observations


An Arecibo Galactic Chemistry An Arecibo Galactic Chemistry SurveySurvey

• First proposal made in 2007 to make a 1 – 10 GHz survey of a number of representative Galactic sources using the Mock Spectrometer in single-pixel mode.

• Unbiased spectral line surveys → information needed to characterize physical and chemical conditions.

• The full range 1 – 10 GHz is relatively unexplored for Galactic sources and many complex molecules have lines at λ < 3 cm.

• “Line confusion” is very much less in this range than at millimeter wavelengths.


Precursor Observations Precursor Observations • Observations made in Oct-Nov 2008.• Targets were star-forming region, NGC2264, and C-rich,

evolved PPN, CRL618.• The single-pixel Mock mode was not ready, so the

precursor observations were made with the WAPPs.• A shallow, but full, 1 – 10 GHz coverage was made for

both objects with a velocity resolution of 0.7 kms-1.

Excited satellite line OH maser in PPN, CRL 618

Methanol in NGC 2264-IRS1 HC3N in NGC 2264-IRS1


Test Set-Up:Oct 5Test Set-Up:Oct 5thth 2009 2009• A second proposal was submitted in Feb. 2009 to make a

full 1 – 10 GHz survey of the ultra-compact source W51e2 in W51 IRS1. This was graded 'A', and awarded 112 hr.

• A preliminary version of the single-pixel Mock mode was made available by Phil Perillat this fall.

• An hour's test time was used to try out a first AGCS C-band set-up for the Mocks on October 5th 2009.

• This had a velocity resolution of 0.3 kms-1, and covered a total band of about 500 MHz, about 50% of the potential coverage (only a single Mock band being available.)

• 4 ON/OFF scans were acquired on W51e2 and the data reduced to get a check of the resulting spectra.


Radio Recombination LinesRadio Recombination Lines

H110α

H111α

H112α

H138β

H139β

H140β

H141β

H161γ


Molecular LinesMolecular Lines

H141β

H2

13CO

H2CO

Excited OH Satellite Line (2Π

½ J=½ F=0–1)


Muchas Muchas GraciasGracias


HI Absorption in the Host Galaxy of QSO CTA 21HI Absorption in the Host Galaxy of QSO CTA 21

CTA 21 at arcsec resolution: CTA 21 at arcsec resolution: contours= radio; contours= radio;

greyscale=opticalgreyscale=optical

CTA 21 at milliarcsec resolutionCTA 21 at milliarcsec resolution

Optical Spectrum of CTA Optical Spectrum of CTA 2121

Radio Spectrum of CTA Radio Spectrum of CTA 2121

100 1000

10000

10

1

0.1

Frequency (MHz)

Flux D

ensity (Jy)

HI absorption in the host HI absorption in the host galaxy of CTA 21 against the galaxy of CTA 21 against the continuum emission of the continuum emission of the central quasarcentral quasar

Observed at Arecibo on 20 Observed at Arecibo on 20 & 21 September 2009 & 21 September 2009 Redshift,Redshift, z z = 0.906 = 0.906 Distance = 7,335,000,000 Distance = 7,335,000,000 light years light years CTA 21 is seen at 46% of CTA 21 is seen at 46% of the present age of the the present age of the Universe Universe

Central Frequency = 745.5 MHz

Analog-to-Digital migration of TV transmissions in June 2009 temporarily freed up the 700–800 MHz band. Arecibo has provided and commissioned a receiver.


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)


Project in progress: (Ryan’s dissertation: coming in August 2010!)Requirements for mitigating ISM effects:Wide bandwidth instrumentation: ISM effects are mitigated by both a) observing at higher frequencies and b) observing with wider bandwidths.Also require instruments with high frequency resolution to perform dynamic spectra analysis (i.e., Mock) complementary to wide bandwidth timing instruments (GUPPI-clone). Need sensitive telescope (i.e. Arecibo) to identify and mitigate propagation effectsRyan would like to thank the AO Staff (especially Tapasi Ghosh) for assistance with the observations

6 months

6 months

The 10000 ASP Times of Arrival


• Detected 14 B fields.

• Detected fields in 5/8 ULIRGs.

• First extragalactic Zeeman splitting detections in emission lines.– Only previous extragalactic Zeeman detection was HI in absorption in

high-velocity cloud around Perseus A (Kazes et al. 1991; Sarma et al. 2005).

• B is similar to local sites of OH masers.– Conditions in regions of massive star formation are similar to those in

Milky Way.

• B is consistent with inferred synchrotron fields.– Probing gas closer to typical ISM density.

Results

AUSAC Meeting April 19 − 20, 2010 Radio Astronomy -- Other Than ALFA Surveys Chris Salter...

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