Software Correlation at JIVE & Real-time e-VLBI in the EVN

Software Correlation at JIVE & Real-time e-VLBI in the EVN

Operations and PI Interaction Astronomy Gains from SFXC Real-time e-EVN status Proposal Tool: recent modifications

Bob Campbell, JIVE

EVN Symposium #12, Cagliari . . . . . . . . . . . . . . . . . . . . . . . . . . 2456940.576 (9/x/2014)

Ops Flowchart (≤ Correlation)

MkIV SFXC: Astronomy Gains

Nsta limited only by available input devices (was 16)

Arbitrary total bit-rate & BWSB (was 1 Gbps & 16 MHz)

~arbitrarily large number of frequency points (was 2048)

Velocity resolution improvements w/o cont. sensitivity penalty

Selectable spectral windowing (Hanning, Hamming, cosine, tophat)

~arbitrarily small integration times (was ¼s)

Large Nfrq & small tint together wider-field mapping

Improvements in correlated data Pure station-based fringe rotation to center of earth

Decoupled correlation/delay-tracking FFT sizes

Consistent cross-polarization handling

MkIV SFXC: as seen by userNsta

2 . Nsb . Npol . Nfrq ≤ 131072 . R

Nsta = (4,8,12,16); Npol = (1,2,4); Nchan ≤ 16; Nfrqmax = 2048

Recirculation: R ≤ 16MHz/BWsb ; Nfrqmax still 2048

(if 8 MHz SB) 9—16 Sta 1 SB 2 Pol 512 Frq (R = 2)

(if 2 MHz SB) 9—16 Sta 1 SB 2 Pol 2048 Frq (R = 8)

Maximal velocity spacings (Nfrq=2048, Δv in [m/s])

Specify desired velocity spacing & required continuum sensitivity (set BWsb, then Nfrq)

BWsb [MHz] Δ [Hz] Δ1420 Δ1665 Δ6668 Δ22235

16 7813 1651 1408 351 1052 977 206 176 44 13

MkIV

SFXC

SFXC: Completely New Astronomy

Multiple output phase centers within a wider field

Pulsar Gating/Binning Both incoherent and (new) coherent de-dispersion

Space VLBI (cf. Duev poster, Molera talk) Near-field correlation (solar-system, GNSS targets) Orbiting antenna (RadioAstron)

“Phasing up” the EVN

Mixed-bandwidth, mismatched-sideband correlation (enables inclusion of wider set of heterogeneous back-

ends)

SFXC: Pulsar Gating/Binning Gating = arbitrary start/stop interval within PSR period

Binning = arbitrary number of bins within the gate Each bin separate correlation / output IDI-FITS file

0329+541.4 GHz

Pulse profile (1 gate, 100 bins)

Sieber et al 1974

SFXC: Wide-Field Mapping Essentially unlimited max-Nfrq, min-tint: can map area

on the sky ~single-dish beam w/ minimal smearing Price = huge output data sets (record soon ~5.5TB FITS files)

Multiple phase-center correlation: outputs only subsets

of the full area (user exps. up to ~200-300 phs.ctrs)

Typical 1st-correlation Nfrq ~16k; tint ~ 4—15 msFurther processing-factor “penalty” small

Example validation run: same source correlated at two positions 1.4’ apart; |Δφ|Ef-Hh = 0.3o pk-to-pk.

Ef-Hh

6cm

SFXC: “Phasing up” the EVN Most applicable to pulsar observations

Correlate phase-reference obs. “normally”

Obtain fringe solutions for as many sources as

possible

Apply fringe solutions back into model for each station

Re-correlate with new model

Output as single (CoE) station in PSR-FITS

a.k.a. filter-bank data

run through PRESTO to fit for pulsar P, Pdot, etc.

SFXC: “Phasing up” the EVN

ms-PSR M15A

in Glob.Clust.

M15

Ar,Ef,Gb,Jb,

On,Tr,Wb

~100 min

Real-time e-EVN Science Proposal-driven e-EVN science observations

1st observation = 16 Mar 2006 (6 stations at 128 Mb/s) Nowadays, a network of 9-10 stations at Gbps is routine Typically ~25-30% of EVN observing time e-EVN network still misses KVAZAR stations & Urumqi

Evolution of e-EVN procedures ~monthly 24-hour runs (+4hr prelim. test) on fixed dates

e-EVN also in regular disk sessions (longer runs)

Proposals now within standard proposal-submission cycles Proposal Class for “triggered” observations (10 since Apr’08) Proposal Class for “short” observations (35 since May’08) Any EVN or GLOBAL proposal may contain e-VLBI observation(s)

Target of Opportunity Observations (49 since Sep’07)

The EVN / e-EVN

e-EVN Operational Bandwidth

Station ConnectionEffelsberg 1024 Mbps (4x in tests)

Westerbork 1024 Mbps

Jodrell Bank 1024 Mbps

Medicina 1024 Mbps

Noto 1024 Mbps

Onsala 1024 Mbps (4x in tests)

Torun 1024 Mbps

Yebes 1024 Mbps (4x in tests)

Sheshan 1024 Mbps

HartRAO 1024 Mbps

Arecibo 512 Mbps

Metsahovi 1024 Mbps

ATNF: 1 Gbps (At,Mp,Pa)

SRT expected soon

Robledo to start tests

Irbene connection in place

Observing Request Tab (Array)

e-EVN now per observation; controls array, correlation parameter choices

Observing Request Tab (Changes to Array Selection)

New category: “special” EVN stations (per band)

New category-specific help

Observing Request Tab (New Help for Array Selection )

Observing Request Tab (Out-of-Session Obs)

Any observation can contain one or more out-of-session segments; new dialog box for describing criteria for

minimally-required array

Obs. Rqst Tab (Format & Correlation)

Some impossibilities pass undetected

Updated for SFXC

capabilities; e-EVN

selection

Solar Activity

Remaining in solar-medium

range since the

previous EVN symp.

Moderate uptick near the start of

2014

Predictions for this Solar Cycle

Sep’10 & ’12 predictions: solar max. in mid-2013 at

140 sfu.

Sep’14 pred: solar max.

just passed.

ref: Space Weather

Prediction Center, via

www.sec.noaa.gov

Summary Pre-/Post-correlation PI Support

Help available — don’t have to wait until last minute Archive: FITS, pipeline, standard plots, feedback RadioNet3 EVN Trans-National Access program

EVN Software Correlator at JIVE (SFXC) Astronomical applications beyond the MkIV correlator More straightforward capacity limitations

e-VLBI now standard/indispensable facet of EVN Proposal Tool “Observation Request Tab”

continually tweaked to reflect new capabilities