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

1. 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)

2. Ops Flowchart (≤ Correlation)

3. 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

4. MkIV  SFXC: as seen by user MkIV Nsta2 . 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) SFXC

5. 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)

6. 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+54 1.4 GHz Sieber et al 1974 Pulse profile (1 gate, 100 bins)

7. 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 ms Further 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

8. 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.

9. SFXC: “Phasing up” the EVN ms-PSR M15A in Glob.Clust. M15 Ar,Ef,Gb,Jb, On,Tr,Wb ~100 min

10. 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)

11. The EVN / e-EVN

12. e-EVN Operational Bandwidth ATNF: 1 Gbps(At,Mp,Pa) SRT expected soon Robledo to start tests Irbene connection in place

13. Observing Request Tab (Array) e-EVN now per observation; controls array, correlation parameter choices

14. Observing Request Tab (Changes to Array Selection) New category: “special” EVN stations (per band) New category-specific help

15. Observing Request Tab (New Help for Array Selection )

16. 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

17. Obs. Rqst Tab (Format & Correlation) Updatedfor SFXC capabilities; e-EVN selection Some impossibilities pass undetected

18. Solar Activity Remaining in solar-medium range since the previous EVN symp. Moderate uptick near the start of 2014

19. 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

20. 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 MkIVcorrelator • More straightforward capacity limitations • e-VLBI now standard/indispensable facet of EVN • Proposal Tool “Observation Request Tab” continually tweaked to reflect new capabilities