Present and future e-VLBI / EVN2015 science Zsolt Paragi, JIVE.

Present and future e-VLBI / EVN2015 scienceZsolt Paragi, JIVE

2007 March 1-2, Dwingeloo Present and future e-VLBI... EVN2015 science Slide #2

The European VLBI NetworkWhat are we doing not so good at the moment:

• No real frequency agility• Limited observing time• Little support for ToOs• Slow science turnaround time (from proposal to paper)

Although most of these problems are not directly related to e-VLBI,all of these are addressed today in the framework of e-VLBI developments.

The EVN2015 has to be a real-time array with great frequency coverage andsensitivity, and should operate throughout the whole year. And these tapesbelow will be gone long time before that!

http://www.evlbi.org/

http://www.jive.nl/

http://www.evlbi.org/

http://www.jive.nl/


The end of the tape era• Tape recording had limited performance (parityerrors), and • limited data rate (256 Mbps; 512 Mbps with two write heads).• Tapes were expensive• Tape playback units were not easy to maintain

• Disk based recording systems were developed at Haystack (Mark5A) and Metsahovi Radio Observatory (PC EVN)• And it worked!• The EVN is fully disk operational (Mark5A) since early 2004• Cheaper, off the shelf technology, perfect recording; data rate up to 1 Gbps

http://www.haystack.edu/tech/vlbi/mark5/

http://www.haystack.edu/tech/vlbi/mark5/


Disks+ftp VLBI: reliability!

• Disk recording is better quality, but it also provides a way to quickly check telescope performance: ftp tests

• 2-4s data at 256 Mbps 64-128 MB files, may be transferred through the Internet!

• Data processed by a software correlator developed in NICT, Japan

• Since late 2004 there are regular ftp tests during EVN sessions.

• The software correlator runs on a PC cluster

• Feedback to telescopes used to take at least a week, now it is a matter of minutes

• OK, let us see what else can we improve…


Select your source

Write an observingproposal

EVN PC makesa decision

Publishingresults

EVN schedulerprovides a date

1-2 weeks 2-3 months 2-3 months

Observe with VLBI

Data correlation

Data processing

… another 2-3 months well, why would you hurry?

VLBI observations timeline

THIS MUST CHANGE!


Target of Opportunity projects

An example: the huge flare of SGR1806-20

• SGR1806-20 is a soft gamma-ray repeater aneutron star with very strong magnetic fields, a magnetar

• Produced the greatest explosion witnessed byhumans in our Galaxy, on 27 December 2004

• Observations with various instruments, also VLBI (with the VLBA array)

• Could not image reliably because of lack ofknown calibrator in the vicinity of the target!

Is there a way to do these projects more efficiently?Is there a way to get the data and analyze themquickly???

Fender et al. (2005), MNRAS 367, L6


What is EXPReS?• EXPReS = Express Production Real-time e-VLBI Service• Three year project, started March 2006, funded by the European

Commission (DG-INFSO), Sixth Framework Programme, Contract #026642

• Objective: to create a distributed, large-scale astronomical instrument of continental and inter-continental dimensions

• Means: high-speed communication networks operating in real-time and connecting some of the largest and most sensitive radio telescopes on the planet

http://www.expres-eu.org/

http://www.expres-eu.org/


Jodrell BankUK

OnsalaSweden

MedicinaItaly

TorunPoland

WesterborkNetherlands

Telescopes connections (early 2007)

JIVE

10Gb/s

1Gb/s

1Gb/s

155Mb/s

CambridgeUK

2.5Gb/s

1Gb/s

e-MERLIN

?????

Soon available: Effelsberg,Yebes 40m, Shanghai …

http://www.jive.nl/jivecam


e-VLBI activities in 2006/2007• There are regular e-VLBI test observations in every six week (on average)

• Normal operations at 256 Mbps (Cm, Jb2, Mc, On, Tr, Wb)

• Fringes to several telescopes at 512 Mbps, most recently to Mc

• 24h time is pre-allocated for science observation during each e-VLBI test

• Observing proposals may be submitted two weeks before the advertised date

Science projects observed in 2006/ early 2007:

Cyg X-3, 20 Apr/18 May, 128 Mbps, Tudose et al.

GRS1915, 20 Apr, 128 Mbps, Rushton et al.

LSI +61.303, 256 Mbps, 26 Oct, Perez-Torres et al.

Algol, 26 Oct/14 Dec, 256 Mbps, Paragi et al.

Calibrators near M81, 14 Dec, 256 Mbps, Brunthaler et al.

INTEGRAL microquasar candidates, 14 Dec, Pandey et al.

16 XRBs adaptive run, 29/30 Jan, Spencer et al.

Calibrators, 21 Feb, Fender et al.


First refereed journal papers:Rushton et al. (2007), MNRAS 374, L47

Tudose et al. (2007), MNRAS… very soon

Cyg X-3


LSI 61+303 preliminary results:

Perez-Torres et al. (in prep.)

Gamma-detected XRB candidate;

Recent VLBA observations (Mioduszewski et al.) suggest interacting pulsar wind…

e-EVN, MERLIN, CHANDRA Observations on 26 October 2006


Algol preliminary results:

Csizmadia et al. (in prep.)

26 October 2006


512 Mbps e-VLBI run

1/2 February 2007

(Cm),Jb2,On,Mc,Wb

And Ef, Sh, Yb … coming:We are almost there!!!


e-VLBI challenges

• We are already very good in quick science turnaround: on the fly

data processing/pipelining is possible!

• At 512 Mbs and with Effelsberg, Shanghai and other new telescopes,

we will also be very good in sensitivity and resolution (in 2007/2008)

BUT

• We are poor with immediate good calibration

• The current system is not suitable for real ToOs

• We have to be able to produce high dynamic range maps of sources

varying on timescales of hours (=>EVN2015)

• We must be able to change schedule on the fly to be able to observe

e.g. new transients with poor coordinates (=>EVN2015)


Example: the Algol miniflare (14 Dec 2006)

Csizmadia et al. (in prep.)

Variable flux, positionand structure withinhours!


Westerbork e-EVN as a unique instrument

• Westerbork Synthesis Array data may help in calibration (amplitude, linear

and circular polarization)

• May help to confirm detection/non-detection of weak targets

• Could be used as a ‘built-in’ alert instrument for the e-EVN

• Wb can help improving coordinates of new transients…

• …with adaptive scheduling, this could be immediately used for

the VLBI array

• Not to mention the additional information on the very large-scale

structure (which we normally waste when we do not reduce Wb data

along with the EVN)

Will Westerbork be still around in 2015???


The e-EVN as an alert instrument? • Because we are not good in responding ToOs, but good in providing quick

results, can we turn around the logic?

• Initially could monitor known transient sources (e.g. microquasars like

GRS1915+105) in a snapshot mode during the e-VLBI tests, regularly.

• In case of a flare, report to the community, providing 0-epoch maps!

(not possible when a ToO VLBI run follows a single dish trigger)

• Easily accessible for the whole astronomical community, ready maps from

the EVN archive (all public!)

• With more sensitivity and dynamic scheduling, may continue this with

new X-ray transients or gamma bursts

How shall we select these key science targets?

Can we contribute to X-ray and gamma ray missions like GLAST?

Have invested a lot of money in e-VLBI, now let us invest a great deal of observing time!


EVN2015 science I.Microquasars • Besides the present known radio-jet XRBs, a much larger fraction of the X-ray binaries will be detected by EVN2015.

• Initial phases of flare evolution / jet proper motion in the first 100AU scales is not known.

• Observation of mas-scale jet structural changes just before and during the early stages of a flare is necessary to understand better disk-jet coupling.

• A change in Lorentz factor is predicted – how could we observe that?

• Can we detect circular polarization at sub-mJy levels? Jet composition?

• Is there an outflow or jet/ISM interaction region roughly perpendicular to the jet in all microquasars (like in SS433)?

• What is the difference between the NS and the BH microquasar outflows?

• Is there an underlying high Lorentz-factor jet in all microquasars?


EVN2015 science I.Microquasars

• So, what is happening to the core-jets during an outburst?

Paragi et al. 1999New A.R. 43, 553


EVN2015 science II.Other radio active binaries

• Late-type stars show magnetic activity, a great stellar population to be studied by EVN2015.

• At VLBI resolution one could resolve the magnetosphere of nearby spotted stars, and image the stellar spots in the radio directly!

• Radio flaring Algol and RS CVn sources could be easily observed (on the fly selection of active targets)

• What is the relation of the flares to magnetic activity or mass-exchange in these binaries? For example in Algol, one could resolve the Roche-lobe and even the stellar disks with the EVN.

• Are these sources producing collimated outflows?


EVN2015 science III.Gamma bursts

• Is there prompt radio emission? LOFAR will do it at low frequencies. Can we constrain cm-wavelength emission (models do not predict, but…)?

• Will the EVN2015 (or earlier) be able to observe the prompt burst?

• Theories/observations predict a jet break up days after the burst, with sudden drop of the Lorentz-factor; needs high frequency (≥22 GHz) very sensitive VLBI observations to study proper motion. These are far too faint for cm wavelength studies with space-VLBI.

• What is the relation between SNIb/c and gamma bursts?

• Can we observe off-axis GRBs in the radio?


An old story: the first e-VLBI science result (continuum)

• SN2001em was discovered on 15 September 2001 in UGC11794 galaxy (Pepenkova 2001).

• Filippenko and Chornok (2001) classified it as type Ib/c, most likely Ic.

• Exceptional radio and X-ray luminosities(off axis GRB, developing late radio emissiondue to jet break?),

• Not quite a 1 mJy radio source

• EVN observations: Cm, Jb2, On, Tr, Wb (128Mbps), +Arecibo 300m (64 Mbps)at 18cm, on 2005 Mar 11

• Tentative detection (4.5 ) of the first real faint target with e-VLBI

Paragi et al. (2005), MSAIt 76, 570

Needs better resolution and sensitivity!=> EVN2015


EVN2015 science IV.Extragalactic XRBs, ULXs, IMBHs

• EVN2015 will have the sensitivity to study microquasars in nearby galaxies

• Ultra-luminous X-ray sources: all super-Eddington accreting XRBs with geometric beaming of X-rays, or are there intermediate mass black holes as well?

• The superior sensitivity of EVN2015 will be able to constrain black hole masses in ULXs, and will provide resolution to image their (sub-) pc-scale structure. More resolution together with VSOP-2!

• Again, the e-EVN could monitor ULXs and alert community in case of a radio detection.

• With wide field of view imaging, could monitor whole (or part of) nearby galaxies, looking for radio transients; note that e-MERLIN and e-VLA could do this as well, but we would be late with follow up VLBI observations!


EVN2015 science IV., ULXs…

The minimum detectable black hole mass



The minimum detectable black hole mass



Predicted ULX radio flux densities



Predicted ULX radio flux densities

Present and future e-VLBI / EVN2015 science Zsolt Paragi, JIVE.

Documents

evlbi activities

ftp vlbi

vlbi developments

evn2015 scienceslide

framework of e

vlbi data correlation

vlbi observations timeline

european vlbi network