PY 2010 NAIC Progress Report & Program Plan Review 2nd December 2010 Radio Astronomy: Other Projects...

PY 2010 NAIC Progress Report & Program Plan Review2nd December 2010

Radio Astronomy: Other Radio Astronomy: Other Projects Projects

Chris Salter Chris Salter

Arecibo Observatory (National Astronomy & Ionosphere Center)


Arecibo Astronomy Observing DetailsArecibo Astronomy Observing Details

-- 57% of passive astronomy telescope time for large (≥300 hr) survey projects:

currently all using ALFA or LBW receivers.

-- 43% of passive astronomy telescope time for other (PI) astronomical studies (72 projects).

-- Frequency coverage: 327, 430 & 800 MHz, 1.1-10 GHz via 6 receivers + ALFA.

For PY 2009;


Pulsar HighlightsPulsar Highlights • Timing of binary pulsar PSR J1738+0333 provides the most constraining limit yet on dipolar gravitational wave emission. It also excludes all TeVeS (Tensor-Vector-Scalar) theories, the relativistic version of MOND. This reaffirms the existance of dark matter.

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

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

the second least luminous pulsar known!

• The young, energetic radio/X-ray pulsar, PSR J1930+1852 (P=0.136 s), which is situated within the supernova remnant, SNR G54.1+0.3, has had its braking index detemined to be 1.941± 0.001.

Arecibo Timing and Arecibo Timing and γ-Ray γ-Ray PulsarsPulsars

Msec-period PSR J2043+1710 was discovered at Nançay coincident with a compact unidentified Fermi source. This PSR is too weak to measure accurately anywhere but Arecibo, whose timing enabled phase-folding of the Fermi/LAT data, revealing γ-ray pulsations.


High Time Resolution PSR ObservationsHigh Time Resolution PSR ObservationsFull-Stokes, single-pulse observations of “normal” pulsars with ~50 μs time reso lution.

Trec

= 590 μs PSR B1929+10 Trec

= 59 μs PSR B2020+28 Trec

= 59 μs

• Find multiple substructures of μsec duration that are almost 100% linearly polarized.

• Indicates emission regions of size ≤ 15 km.

• The 305-m dish is the only radio telescope capable of detecting such substructures in the single pulses of “normal” pulsars.

• Mitra & Rankin suggest that with even higher time resolution would likely reveal even finer coherent temporal structure.


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 through a cloud of HI in the ISM with T

S= 100 K, τ = 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!)


Red Dwarf “Pulsars”Red Dwarf “Pulsars”

• A number of ultra-cool dwarf stars have been observed at Arecibo displaying similarities between the pulses measured. Example of TVLM 513-46546 (left) and 2MASSW J0746425+200032 (right) in Stokes-V.

• Pulses have brightness temperature > 1015 K. For electron cyclotron maser emission, magnetic field strengths of ~1650 Gauss are implied.

• Simultaneous Arecibo, Hα, optical photometry, and NIR spectrophometry of TVLM 513, show in-phase variations for radio, Hα, [OI] and the optical continuum.


HI Forbidden-Velocity WingsHI 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+3.0 & 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 G39.0+4.0: Red = +110 – +135 km/s, Green = +95 – 110 km/s, Blue = +80 – +95 km/s. Stars = Early-type stars in field; Triangles = Pulsars


An Arecibo Galactic Chemistry SurveyAn Arecibo Galactic Chemistry Survey • To exploit the low “spectral line confusion” for 1 – 10 GHz to characterize

the physical and chemical conditions in Galactic sources.• Precursor observations made in 2008 on star-forming region, NGC2264,

and C-rich, evolved PPN, CRL618. These were shallow 1 – 10 GHz coverages with Δv = 0.7 kms-1.

• Main survey commenced in 2010 studying W51e2 with Δv = 0.3 kms-1.

Excited satellite line OH maser in PPN, CRL 618

CH3OH in NGC 2264-IRS1 HC

3N in NGC 2264-IRS1

H112α in W51e2 H2

13CO and H141β in W51e2

H141β

H213CO

H2CO in W51e2 Excited Satellite OH in W51e

(2Π½ J=½ F=0–1)


HI Absorption at HI Absorption at zz ~ 0.9 ~ 0.9

HI absorption in the host galaxy HI absorption in the host galaxy of CTA 21 against the 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 = 5866 MpcDistance = 5866 Mpc CTA 21 is seen at 46% of the CTA 21 is seen at 46% of the present age of the Universe present age of the 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.

HI absorption in the host galaxy HI absorption in the host galaxy of 4C+15.05 against the of 4C+15.05 against the continuum emission of the continuum emission of the central quasarcentral quasar

Observed at Arecibo on 3, 4 & Observed at Arecibo on 3, 4 & 5 October 20105 October 2010 Redshift,Redshift, z z = 0.833 = 0.833 Distance = 5283 MpcDistance = 5283 Mpc Resolves optical disagreement Resolves optical disagreement between between zz=0.405 and 0.833 =0.405 and 0.833

Central Frequency = 780.4 MHz

HH22CO at 4830 MHzCO at 4830 MHz

OH at 4660 MHzOH at 4660 MHz



HCN at 4488 MHzHCN at 4488 MHz

CHCH22NH at 5290 MHzNH at 5290 MHz

Arecibo Spectra for Zw 049.057Arecibo Spectra for Zw 049.057

Molecular Lines in Luminous IR GalaxiesMolecular Lines in Luminous IR Galaxies

Arecibo Spectra for Arecibo Spectra for NGC660NGC660

Variable Excited OH Masers Variable Excited OH Masers at 4751 & 4766 MHzat 4751 & 4766 MHz

(Excited OH Line at 4660 MHz is (Excited OH Line at 4660 MHz is below noise.)below noise.)

HH22CO at 4830 MHzCO at 4830 MHz

25 Dec 07 – 07 Jan 08

7 Aug 08 – 10 Sep 08

24 Dec 08

Co-added RRLs H109Co-added RRLs H109α–H114α α–H114α (λ6 cm)(λ6 cm); rms noise = 70 μJy/beam; rms noise = 70 μJy/beam


An HAn H22O Maser at O Maser at zz = 2.64 = 2.64

• H2O maser detected in the

gravitationally-lensed quasar MG J0414+0534 at Effelsberg.

• Monitored at Arecibo each 6 weeks for 15 months from Oct. 2008.

• Line profile is very stable, with velocity drift of line peak < 2 kms-1yr-1.

• Main line blue shifted relative to systemic velocity favors association of the maser with the relativistic jet.

• If confirmed, tentative red-shifted line at +470 kms-1 would favor a disk-situated maser.


Arecibo VLBI Highlights Arecibo VLBI Highlights –– 20102010

• Continued HSA, EVN and Global Array operations.

• eVLBI science runs at 256 & 512 Mbit/sec.

• Acquisition, construction and infrastructure development for the 12-m VLBI phase-reference dish.

• Acquisition of 2 × Mark-5C recorders, and the imminent delivery of 2 × digital back-ends (RDBEs).

The High Sensitivity Array (HSA)The High Sensitivity Array (HSA)

The EVNThe EVN


e-VLBI: Monitoring the M87 Jet during a TeV Outburst

Optical HST image of M87 Jet and a knot of hot gas, HST-1, seen to be brightening in 2005, with subsequent TeV outbursts.

Superluminal motion (V

app~2.7c) in HST-1

during a TeV outburst

The inner Jet (collimated for ~200 mas) and the weaker complex, HST-1 (at 800 mas from the core), imaged at 5-GHz, with resolution 7 x 3 mas, and map noise of 0.12 mJy/beam.

Nov19

Jan27

Feb10

Nov19Nov19

Mar02

Mar30


VLBI Sensitivity UpgradeVLBI Sensitivity UpgradeIncreasing the US VLBI data recording rate to at least 4 Gbps by 2010 was a

goal set by the Taylor Committee (2004).

Arecibo is in the process of:1. Increasing the Recorded Bandwidth: (a) Replacing our analog DAR with a Digital Back End (RDBE). Arecibo has

ordered two RDEs from NRAO, and delivery is expected by the year end.

(b) Upgrading to the Mark5C recording system. Arecibo has purchased and received two Mark5C units from Conduant Corp. Control software is under development at Haystack and will be installed in our units there.

2. Increasing the Integration Time: The low 305-m antenna slew rate can lead to >50% loss of integration time in

phase-referenced VLBI. The new Arecibo 12-m dish will track the phase- calibrator continually, while the 305-m tracks the target, just occasionally visiting the calibrator. Phases derived from the 12-m data will be applied to the 305-m data under the assumption that the same ionospheric corrections apply to both data sets.


The Arecibo 12-m AntennaThe Arecibo 12-m Antenna

12-m Antenna Site

The Arecibo 12-m Patriot Antenna

Access Road (then nearing completion)


The Arecibo 12-m Antenna The Arecibo 12-m Antenna

Why 12-m?: A 12-m antenna provides a baseline sensitivity within a factor of 2 of a VLBA dish. Sources brighter than ~110 mJy can be used for phase referencing.

Frequency Coverage: L, S, C & X bands are required for astronomy with the 305-m dish; S/X bands are being installed initially. Thereafter, a 1 – 12 GHz multi-frequency front end is anticipated.

Other Potential Uses: (a) Possible participation in regular VLBA operations, (b) VLBI2010; (c) The L-band, voltage beamwidth of the 12-m antenna contains all 7 ALFA beams, opening up the possibility of multi-beam interferometric applications, (d) Education and research applications with Puerto-Rican universities and other educational establishments. (“Science with the 12-m Workshop”: May 2010)


Anticipated Developments over PY 2011Anticipated Developments over PY 2011

• Continued development towards a 40-beam focal-plane phased feed array to give an HI mapping array with the observing speed of ASKAP or MeerKAT.

• Developments towards replacing the present four receivers covering 2 to 8 GHz with two broader-band systems.

• Developments towards bringing the RF signals directly to the Control Room.

• Completion of VLBI equipment upgrade to a digital backend and Mk5C recorders allowing regular recording at up to 4 Gbits/sec.

• Implementation of the VLBI “phase transfer” methodology from the 12-m calibration data to the 305-m target data.


Muchas Muchas GraciasGracias


VLBI Sensitivity Upgrade VLBI Sensitivity Upgrade Increasing the US VLBI data recording rate to at least 4 Gbps by 2010 was

a goal set by the Taylor Committee.

1. Increasing the Bandwidth: Arecibo is in the process of:

(a) replacing the analog DAR with a Digital Back End (RDBE). - The Digital Down Conversion (DDC) personality consists of four independently tunable sub-bands per IF, with bandwidths 0.5 - 256 MHz and 1–8 bit output sample precision. There is also a Polyphase Filter Bank (PFB) personality with 32 sub-bands spanning the 500-MHz wide IF. Output is via 10-Gbit Ethernet transporting individual sub-band packet streams. Maximum data rate of 8 Gbps. Arecibo has ordered two RDEs from NRAO.

(b) upgrading to the Mark5C recording system developed by Haystack & Conduant Corp. Control software is still under development at Haystack. Arecibo has purchased and received two Mark5C units.


2. Increasing the Integration Time

VLBI is severely limited by ionospheric and tropospheric phase fluctuations, leading to a loss of coherence. As a solution, many VLBI observations these days are taken in “Phase referenced” mode. The most commonly used form of this mode needs slewing between the target and a strong, compact calibration source (generally within a few degrees of the target) every 3-4 min. Phase, derived from the calibrator, is then applied to the target data.

The low slew rate of 305-m antenna can lead to over 50% loss of integration time in phase-referenced VLBI.


ReceiversReceivers

800


The Three Little PigsThe Three Little Pigs(PI: Josh Goldston Peek)

• Tiny clouds found at b ≈ 85°; Δθ ≈ 1'.

• VLA follow-up shows condensed cores , optically-thick, with TB ≈ 10K.

• Arecibo measures Magnetic Field strength ~14 μG → 200 – 800 times the magnetic pressure of the WIM.

• Upper limits on OH emission from Arecibo.

Now Pigs by the Drove!Now Pigs by the Drove!(Ayesha Begum & Snezana Stanimirovic)

•About 100 compact, cold clouds, isolated from Galactic emission in a limited area of the TOGS/TOGS2 survey.

• Median angular size ~5', Tb ~ 0.7 K, FWHM ~ 4.2 km/s,

and NHI

~ 5 × 1018 cm-2.

• Clouds deviate from Galactic rotation by 10 – 40 km/s, and evidence for multiphase medium and velocity gradients.


Existing Arecibo VLBI CapabilityExisting Arecibo VLBI Capability

DAR - VLBA4

MK5A

Max 1-GHz IF

The Big Dish(Gain~10k/Jy,SEFD~3-5 Jy)

Correlator

Internet

FedEx

1024 Mbps256 MHz (max)2 x 8, 16 MHz.05, .5 (#1,2 Rxs), 1 GHz

327, 800, L, S-Lo, S-High, C, C-High, X

Total data rateTotal single-pol RF Bandwidth

# of BBCs & Max ∆ν/BBC

Max. IF bandwidth/Rx

Receivers

Co-Observing Networks:

1.VLBA + Ar & the HSA (HSA, includes the phased-VLA,

GBT, EF)2. European VLBI Network + Ar 3. Global - Network4. eVLBI (Real-time VLBI via

internet: as yet with the EVN only)


• A continuum observation, =18-cm, data-rate=512 Mbps, i.e. 128 MHz of RF bandwidth, dual-polarization, = 120 minutes on source:

Arecibo’s Contribution to the ArraysArecibo’s Contribution to the Arrays

• A spectral-line observation, =18-cm, 64 channels over 1-MHz, 2 pol, 120 min.

0.25 mJy/beam/ch 0.62 3.00.310.9 mJy/beam/ch

VLBA+Y27+Gb+ARVLBA+Y27+GBVLBAEVN+AREVN

HSA (VLBA+Y27+EF+GB+Ar) -Ar

1σ Image noise = 3.3 μJy/beam 7.1 μJy/beam

EVN+Ar-Ar

1σ Image noise = 3.8 μJy/beam 9 μJy/beam

Global (EVN+VLBA+Y27+Gb)+Ar-Ar

1σ Image noise = 2.5 μJy/beam 4.7 μJy/beam


Operational block diagram (evolving)

PY 2010 NAIC Progress Report & Program Plan Review 2nd December 2010 Radio Astronomy: Other Projects...

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