PoS(RTS2012)048

sa.it SKA time. VLBI VLBI - uropean uropean important in real

http://pos.sis Most Most of these the technology

. ing from around . Moreover,

iques VLBI VLBI has in the E - with with many elements

ShareAlike Licence. ShareAlike - re with a significant user community astronomy roadmaps

other SKA pathfinders, VLBIbe a will SKAother pathfinders,

time science techn - NonCommercial - telescopes for VLBI are emerg VLBI VLBI over the last five years how demonstrates

- VLBI VLBI networks

At At the same time JIVE is pushing

of of e developments developments have a great synergy with the great possibilities for training and outreach. With and the outreach. for newtraining possibilities great

s ncements ncements of the sensitivity and image quality delivered by the future. in the SKA pathfinder role that e

for the future.thefor offer

connectivity connectivity and real

1

feature in national and European further enha

be be done in

elements

recognized :Past, Present and Future instrument

rrelators that can connect exploring exploring

he he exceptional progress technological VLBI T

for , which

Radio Radio

he This This is - Leiden, Leiden University Leiden Leiden, .

pacity pacity co etwork many many new initiatives to build or outfit

N , ific capabilities, especially those complementary to Speaker 20, 2012 20,

- [email protected] LBI LBI

the world. T preparations V visible locally its with scient flourishing scientific scientific scientific topics science themes call for VLBI networks. sensitive VLBI should for large ca Indeed Almost two decades after the establishment of the Joint Institute for VLBI in (JIVE), the the (JIVE), Europe in VLBI for Institute Joint the of establishment the after decades two Almost infrastructu scientific thriving a is Network VLBI European and a healthy proposal pressure. It offers opportunities to address a breadth of 1 mail: mail: Copyright owned by the author(s) under the terms of the Creative Commons Attribution Commons of Creative terms the the under author(s) owned by the Copyright -

 Sky the Resolving UK Manchester, 17 April

Postbus 9513, 2300 RA Leiden, the the Leiden, RA 2300 9513, Postbus E Huib Jan van Langevelde van Jan Huib Europe in VLBI for Institute Joint The Netherlands the Dwingeloo, AA 7990 2, Postbus Sterrewacht And The future of VLBI of future The

PoS(RTS2012)048

a ed the An An The The

from are are

will will be was was the

of of space

there are

s and

resolution.

There ). velopment velopment of . scale perspective perspective in this

tivity domain. The time results, thereby - that was developed a characteristics Huib Jan van Langevelde van Jan Huib

disk disk recording replac - European European scale

. A major improvement to the he he research in masers , I have often taken a European T [1]

resolution . of of radio astronomers all over the

- high by providing real national national and

plans plans

. and potentially enhancing the sensitivity. the scientific focus is thought to be on surveys with arcsecond mm VLBI with ALMA, which promises to - I can enhance the scientific impact under under construction at the proposed SKA sites.

, requiring low frequency receptors at modest

the EVN science vision

on 2 further

mental mental physics. Probably related to this, for all these instruments, requiring sensitive and

detail detail and focus on the next steps on this roadmap to this branch of

local VLBI elements. that VLB

up

in -

of of the SKA term roadmap for the next 5 to 15 years , currently another another revolution - [6]

new will will focus sensitivity. sensitivity. The scientific strength of VLBI will be to provide scientific scientific priorities on for a boost in sensitivity. More capabilities at higher frequency

aspects

http://www.evlbi.org/publications/publications.htm

s earch councils earch

Active Galactic Active Nuclei Galactic (AGN) and in connection the AGN/starburst

and Joint Institute for VLBI in Europe (JIVE) biased ) nce nce case is addressing a wide range of astronomical topics, starting the first phase resolution follow 2 - : EVN2015 ( take radio astronomy into a completely different sensi

during during

JIVE was established as a correlator centre, one of its main ork ork (EVN

global effort has focused on the technical development necessary for the SKA, development necessary has on focused which effort the technical global

years ago years r, r, it has been demonstrated The The EVN scie adio adio astronomers around the world are developing the (SKA) which which will . These efforts continue to be based on The The EVN is developing a long Below Below I will these discuss R When When The European VLBI Network is a joint facility of European, Chinese, South African and other radio astronomy astronomy radio other and African South Chinese, European, of facility joint a is Network VLBI European The

, 2 Scientific motivation Scientific

Background ansients, ansients, pulsars and HI from distant galaxies

institutes funded by their national res cosmological fields, which call are also in demand, for example to probe jet physics close to the black hole event horizon. extreme example of this is the deployment of sub map the shadow of the central Galactic black hole, SgrA*. VLBI VLBI community must set its priorities in view of the world of couple the classical area of jets in discussion. 2. number of initiatives to define flexiblenetworks operatethat globala in collaboration the VLBI of the future, a development that will be synergetic with the technical de the SKA. In recognition of the special nature of this conference VLBI Netw Most Most of the precursor Additionally, science tr baselines to optimize brightness capabilities for high many national initiatives to establish establish to initiatives national many [12] concerted, has fed into two precursor installations enabling enabling new science, boosting the reliability This provides a natural growth path for increasing quality of the science return of VLBI has led to a solid user interest in the technique. Moreove missions, in planetary explorations or funda 1. ability to play back tape reels from 16 stations simultaneously reliability, flexibility and efficiency occurred ten years ago, when hard the tape reels. Then VLBI underwent The future of VLBI of future The PoS(RTS2012)048

survey

resolution - the EVN’s various various new view - as as of rovide capacity - Huib Jan van Langevelde van Jan Huib

. w on the dynamics on the ) 1 by providing high d for population studies that X region. These EVN These region. X

, a vie

. Finally, it has been demonstrated Figure Figure (

[2] facilities [5]

offering

, ennas that participate in VLBI,

lable. Together with large field

3 MERLIN - , but currently the samples under study are limited in z and 43GHz [8] and e

H forming regions in the Cygnus

- . [6] , providing many more triggers, this can be expected to be a time VLBI [11] -

n Europe and beyond. A next generation correlator must p

ore ore coverage at 22G [9]

m ystem of the future the of ystem Parallax measurements of star of measurements Parallax In Galactic astronomy, the study of transient radio sources has already taken advantage

. 1 In all the science areas the VLBI sensitivity must be improved to maintain omplementary omplementary role with the EVLA antennas antennas are planned i fortheVLBI s c are improvements sensitivity bandwidth, in increases Besides sensitivity. similar a at diagnostics also expected from expanding the number of ant booming industry in a matter of years. Pulsar capabilities must feature prominently as well in the coming years, as VLBI pulsar astrometry will harvest the results from be a number of inSKA pathfinders deman that VLBI offers very interesting providing accurate positions scientific of spacecraft. Here too, real applicationstime processing is an important asset for planetary Space missions, by of of the development of real size, until much better sensitivity becomes avai instruments, like LOFAR Figure Figure single a form not do and distance, same the at are masers the all not that demonstrate observations structure spatial small scales that are relevant for star and planet formation. From the same observations usually obtained measurements are distance fundamental very also The future of VLBI of future The stimulated by PoS(RTS2012)048

be be its

etely etely scale

-

. ) 2

t has been the long run will have to to have will not not compl

Figure Figure (

Seventh Framework Framework Seventh (Novel Explorations , there Moreover, i Moreover,

Huib Jan van Langevelde van Jan Huib 3 coverage in the Northern herefore plexity. plexity.

. VLBI VLBI can also help in enhancing NEXPReS - project project has been supported by the which which can be noticed immediately

[8] s

initial continue continue to have

made configurations for the best science. best the for configurations made -

261525.

- 4 work for intercontinental baselines intercontinental for work VLBI VLBI has been the desire to use VLBI on transient

at at very long baseline capabilities are - ly not in its first two phases. T , this array could Although Although the costs in are considerable, currently VLBI can VLBI -

, certain

VLBI has evolved from an experimental technique, connecting a small small a connecting technique, experimental an from evolved has VLBI

- e

time connectivity will be cheaper and more environmentally friendly. - VLBI is not a technique limited to do rapid response science. Because of Because science. response rapid do to limited technique a not is VLBI - 2013) under grant agreement n° RI n° agreement grant under 2013) VLBI VLBI Services) - VLBI - -

speed links potentially add an extra layer of com - ternational collaborations in Global VLBI and by the SKA design on the use of Global baselines and frequencies of 5 GHz and higher. Building on the

Besides Besides reducing the delivery time to the astronomer, e However, However, the project has done more than enabling new science. It has also clearly The The initial argument for developing e In the last decade In the long term, it should be noted th NEXPReS is an Integrated Infrastructure Initiative (I3), funded under the European Union Union European the under funded (I3), Initiative Infrastructure Integrated an is NEXPReS through the FP6 Integrating activity EXPReS, which has stimulated a large omena, omena, being able to access the data on variable sources on the timescale that they vary. time nature it is also much more robust against failure

3

EXPReS programme EXPReS -

uld be envisioned that can be deployed in tailor in deployed be can that envisioned be uld Progress on e Progress focus

Programme (FP7/2007 Programme demonstrated convincingly that e that convincingly demonstrated the flexibility of the observations shipping scarce by recording media. avoiding the complex logistics it is expected that real that are involved in demonstrated that e that demonstrated real and addressed instantaneously. With dedicated connections this has though proven the high to be true, even collaboration between EVN technical staff and European Research NetworkEuropeanResearchandproviders. staff betweenEVN technical collaboration phen Indeed, opening the parameter space accessible to VLBI has turned up resultsand various new science themes have been presentedsome very interesting 3.1 number of telescopes at modest competitive bandwidth sensitivity and imaging into capabilities. The an operational astronomical EC service with Pushing Pushing Robust e hemisphere and encompass the current EVN telescopes. A more co flexible global VLBI array 3. astrometry, pulsar binning and many bit processing. manyand bit binning pulsar astrometry, covered a existing in The future of VLBI of future The for processing these higher bandwidths, but also more flexibility for spectral line science, PoS(RTS2012)048

-

ll be transport data data that can be is that its current

, l recording hardware VLBI VLBI experiment is - Huib Jan van Langevelde van Jan Huib lle time connectivity to these - speed para - ed and process the experiment a second

time output. This way one could overcome -

requires high 5 lation parameters or new astronomical information on, for time operations. of of this service -

. VLBI VLBI is less flexible than recorded VLBI - correlations, correlations, which are for example needed to accommodate large

- would be possible. Such would be a possible. scheme would also end all almost in the development of the VLBI of the future is to implement an e

time are correlated on the fly. Ideally such an e - allow re

VLBI. VLBI. We envision an operational model in which all -

position objective to introduce buffering of the VLBI data in various stages in order to combine the physical physical recordings, as buffering capacity on both ends could accommodate all

), ), as well as software systems that hide the bookkeeping from the VLBI os. os. Implementation source the

Telescope and correlator configuration in the EXPReS network. Real network. EXPReS the in configuration correlator and Telescope , . 2 of of scenari The The next One One way in which e NEXPReS programme NEXPReS

igure example needs relay (many Gbps operators componentstheir and completed directly after the observation, but there can be various logistic, technical and scientific even reasons, to access the data that was buffer time, possibly based on the evaluation of the real limited connectivity to an essentialreprocessing with station, different or corre failures in streaming or correlation. Also VLBI VLBI component for every VLBI experiment that is carried out. By implementing transparent buffering mechanisms at telescope and end, correlator one can address all the current and future bottlenecks in e transported in real in principle all of these advantageous are limitations of the real and recorded of aspects best current correlator, but even so it wi 3.2 F telescopes was established during the course of the project. operations do not numbers of telescopes or spectral line experiments that need mixed bandwidths. It is noted that The future of VLBI of future The PoS(RTS2012)048

. - - 4 or since its Eventually, Eventually,

ffers a number of A critical A item has critical hat hat users can easily VLBI VLBI observations . - Although Although yet only a Huib Jan van Langevelde van Jan Huib for e

he he inherent width of the IF , NEXPReS also has work develop develop a correlator that is field correlation to measure -

binning, binning, wide field imaging and high

must must be to .

. The SFXC platform o at at the of heart the EVN operations

[10]

ted correlator effort focuses on allocating he he current data processor. These are similar [3]

or or 4 in baselines compared to the current), o 2 GHz bandwidth could be realized in each

6 [7] seful to help the correlation of Space VLBI data rates. and maybe a 4 to 8 times better spectral resolution - by testing with 4 Gbps in 2012

has been has new EVN data processor is required. Looking at the architecture

, xample atmospheric conditions into account. into conditions atmospheric xample s data s rate has been offered regularly - that the existing VLBI arrays become much more flexible in

flexible

cessor. cessor. Overall the aim Demand Demand protocols. With these in place, it should be possible to

- t on - more more capacity capacity connections for VLBI experiments and release them back for 4Mbps data - MERLIN, MERLIN, EVLA, APERTIF). Taking future energy constraints into to push the sensitivity or at least 16 Gbp 16 least at or -

term future a large times more powerful than t is capable of processing 16 stations at 1024 Mbps. high - experiments exceed these parameters, the processing is now predominantly This This technique could be u

.

full full 102

as as the correlators for SKA precursors (MeerKAT, ASKAP), and some of the these transparent, high bandwidth caching mechanisms

EVN Mk4 correlator at JIVE that that JIVE at EVN Mk4 correlator

a hundred

guaranteed, guaranteed, For For the longer The The The future use also dictates While While the Besides Besides the introduction of the new filters and digitizers, the DBBC system in the case of the EVN.

Next Generation correlator Generation Next

Technology developmen Technology specifications other pathfinders (e above specifications and the EVN (and anticipate the need to global) process 32 stations (a fact ambitions to have more maybe even 16 4) Gbps (a per second factor stations, one can than the current EVN data pro close to additional additional new scientific capabilities, including pulsar spectral resolution modes. In particular it is very powerful for near spacecraft signals suchfromRadioAstronascurrent the mission dedication dedication in 1998 modest number of carried out on the EVN software correlator at JIVE (SFXC), which implements a more accurate correlation algorithm in a notice. notice. It should be possible to flexibly schedule and e for taking adapt quality, of level guaranteed observations in order to reach a 4.1 frequencies above 10 GHz. Here possibly up t f calling polarization, scheduling and operations. Operational models must evolve in such a way t even on short observations, their for and sensitivity frequency extent, in array optimal the define been to stations all for eventually and array the joins that telescope new any for needed is system This go beyond 1024Mbps. Moreover, the EVN bandwidth is limited by t systems of the telescopes, and this must be addressed at many stations in the future. there is the ambition to go to even higher bandwidths, which will be mostly useful at up. 4. The EVN has started programmes programmes on Bandwidth reserve other applications afterwards. Also the resources flexibly. distribu Using computing resources at the astronomy sites it should farm out the be correlation needs possible for a modest to VLBI network deployed for transient event follow The future of VLBI of future The PoS(RTS2012)048

;

n ) 3 first first

Figure Figure ( inia Radio

It It has been . Recently Recently [5] being being erected in

the Sard

tations. graphically graphically interesting Huib Jan van Langevelde van Jan Huib

e new antenna is while while a larg

7 VN and first fringes have been obtained betwee n the new telescopes of Miyun (50m) and experiments

have have participated in In addition to newly constructed telescopes, the Russian telescopes in the

JIVE is actively pursuing for correlation on FPGA based architectures . [4] Demonstration of the UniBoard prototype during the review of JIVE on March 5 2012 5 March on JIVE of review the during prototype UniBoard the of Demonstration A very interesting option to enhance the VLBI capacity is the project to retrofit existing existing to retrofit project is the VLBI the capacity to enhance option A interesting very One of the main motivations to increase the correlator capacity is the increasing number number increasing the is capacity correlator the increase to motivations main the of One .

3

Telescopes

locations such as the Goonhilly station in Cornwall and the Azores and Madeira. In particular, a large number of antennas have been identified around the recognized African that continent establishing an African VLBI Network capabilities, but offers also is a not great opportunity for building only technological and scientific very capacity in good scientific Africa. KVASAR KVASAR network have recently joined the E antennas. European and Korean communication dishes for astronomical research, as they become obsolete with the advent fibre cables of around the world. The possibilities include telescopes in geo near near future it will be possible to observe with EVN+MERLIN, using all s fringes were obtained with the Telescope (64m) Latvian is reaching completion. I 32m telescope Kunming (40m) and Figure Figure 4.2 of telescopes. In global observations the number of telescopes can already go beyond 16. In the a similar conclusion as was reached by other SKA pathfinder projects. SKA other pathfinder by wasreached as conclusion similar a The future of VLBI of future The consideration, PoS(RTS2012)048

.

a

of of

s uture uture

It It was

phases ,

technical

become

rogram

. ky PoS(RTS2012)005 Moreover, some Moreover, the 22 and 43 GHz in parallel with the

demonstrate demonstrate that the

PoS(RTS2012)012

Huib Jan van Langevelde van Jan Huib

PoS(RTS2012)045 , ,

ecially ecially when it PoS(RTS2012)035 ,

Resolve The S The Resolve

With With all these policy,

All All the above aspects have been to and the imaging quality, while the

continuously continuously

PoS(RTS2012)028 results.

, PoS(RTS2012)032 ) e for training and education, as well as low, in a recent review of JIVE. , s well. This is the VLBI facility that f , PoS(RTS2012)046 Status and Results and Status

thankfully -

8 E and early space VLBI in Europe, Europe, in VLBI space early and E PoS(RTS2012)031 pathfinder , ( PoS(RTS2012)010

It It is important to continue continue , PoS(RTS2012)033 , ly positioned for the future, esp of VLBI in China and its related to EVN to related its and China in VLBI of up SKAup

- we can can we

, play play an important rol ge ge to shape such a Global VLBI ambition

my my research in Europe during the SKA engineering will contribute to the sensitivity to the contribute will

in place, the VLBI of the future could also be much more flexible current status current

- a challen

Resolving The Sky with LOFAR with Sky The Resolving SKA Australian SKA Pathfinder Telescope Pathfinder SKA Australian , , The Story of Space VLBI Space of Story The Space VLBI mission RadioAstron: current status and early science p science early and status current RadioAstron: mission VLBI Space t is The developement The i Space radio astronomy in the next 1000001 (binary) years (binary) 1000001 next the in astronomy radio Space , SS433, microquasars, and other transients other and microquasars, SS433, The beginnings of the EVN, JIV EVN, the of beginnings The

VLBI Astrometry of Planetary Orbiters Planetary of Astrometry VLBI The MeerKAT Radio MeerKAT The

,

hese hese new dishes lities can continue to J. Womersley J. Z. Paragi, Paragi, Z. 79 539, A&A 2012, al., et Sanna, A. Brunthaler, A. Rygl, K.L.J. Schilizzi, R. Vermeulen R. J. Jonas J. Jones, D. Kovalev, Y. R. Booth, Booth, R. Diamond, P.J Gurvits, L. Hong X.Y. However, However, All t All

With With such a facility

PoS(RTS2012)040 scientific ingredients in place ingredientsin scientific [12] [8] [9] [10] [11] [5] [6] [7] [1] [2] [3] [4] Conclusions ascinating ascinating science that can be done with radio astronomy.

formal European Research Infrastructure Consortium (ERIC). and References enable enable cutting edge astrono the Moreover, VLBI national have telescopes a unique role in keeping the public aware of the f recognised, along with the technical developments be concluded that the is institute excellent scientific scientific return, yet providing immediate feedback a follow to order in see to want users definition and construction of the SKA. VLBI faci global distribution allows for more and longer coverage during observations. during coverage more longer and for allows distribution global the new antennas are extending the high frequency capability of the EVN in range. and ready to observe at any time with the most optimal array, never compromising the optimal The future of VLBI of future The 5.