Transcript e-EVN science projects (2006-2008) Zsolt Paragi (JIVE), for the EXPReS project What will e-VLBI offer for us one day? Several Gbps data rates/telescope,

e-EVN science projects (2006-2008)
Zsolt Paragi (JIVE),
for the EXPReS project
What will e-VLBI offer for us one day?
Several Gbps data rates/telescope, greatly increased
sensitivity, “full” uv-coverage, flexibility…
What the e-EVN can do by the end of 2008:
• Open for users, regular observing sessions (10-12/year )
• Sensitivity and resolution comparable to disk recording
• Already more flexibility for rapid response science!
• Rapid feedback, you know if it works, you know what you observe…
• … enables quick decision about more observations (VLBI or other)
• Easy access, easy use – high level of PI support
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #2
Where are we now in capabilities…
Sensitivity and resolution in typical observations, 5 GHz
• e-EVN in 2007, 256 Mbps: 50 uJy/beam, ~6 mas
• e-EVN, 512 Mbps: 35 uJy/beam, ~6 mas
• e-EVN in 2008, 512 Mbps, 17 Jy/beam, ~6 mas (10 Jy, ~1 mas
with Arecibo, Hh, Sh, Ur at lower data rates)
• Full EVN (no Ar), 1024 Mbps, 12 Jy/beam, ~1 mas
• VLBA, 512 Mbps, 30 Jy/beam, ~1 mas
• VLBA+GBT, 512 Mbps, 12 Jy/beam
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #3
… and how far can we go
Sensitivity
• Great 1 Gbps test results; 10 Gbps technology is available
• Max. 1 Gbps with current EVN; 4 Gbps upgrade is investigated
Resolution/imaging
• Sh tested in 2007; Ar, Hh, Ur 512 Mbps coming soon
• Besides do not we do science (just few days year) with a more
global array including Australian and Japanese telescopes???
Flexibility
• Limited e-EVN ToO is possible on previously unscheduled dates,
but flexibility is still an issue
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #4
e-VLBI operations and test results - 2008
• Regular e-VLBI test observations in every six week (on average)
• 24h time is pre-allocated for science observation during tests
• Accepts normal and triggered proposals, more ToOs are supported
• Science operations (so far) at 1.6 and 5 GHz, max. 512 Mbps with
Cm, Ef - new, Jb2, Mc, On, Tr, Wb; Mh - possible
Tests (more by Arpad, Harro, Paul):
• With packet dropping near 1 Gbps 
• Mixed data rate mode demonstrated
Ar, Hh, Sh, Ur can join science obs!
• Four-continent fringes
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #5
The two newest members of the e-EVN in 2008 (AJPoD by Stefanie Muhle)
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #6
Science results from the ‘Oz-demo’
ATCA, Mopra and Parkes observations at 512 Mbps, correlated at JIVE.
Target: the nearby supernova in the LMC, only visible from the South.
One of the breathtaking
Hubble Space Telescope
images of SN1987A
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #7
And with VLBI…
Various fits to the data to measure the size
of the expanding remnant.
Tingay et al., (in prep.)
Highest resolution image of SN1987A
so far (first VLBI!) – not bad for a
three telescope array. Countours shows
an earlier ATCA image.
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #8
e-EVN science projects in 2006/2007
• Cyg X-3, 20 Apr/18 May 2006, 128 Mbps, Tudose et al.
• GRS1915+105, 20 Apr 2006, 128 Mbps, Rushton et al.
• LSI +61.303, 256 Mbps, 26 Oct 2006, Perez-Torres et al.
• Algol, 26 Oct/14 Dec 2006, 256 Mbps, Paragi et al.
• Calibrators near M81, 14 Dec 2006, 256 Mbps, Brunthaler et al.
• INTEGRAL microquasar candidates, 14 Dec 2006, Pandey et al.
• “double header” run, 15 XRBs, 29 Jan 2007, Rushton & Spencer
• Calibrators, 21 Feb 2007, 256 Mbps, Tudose et al.
• J2020+3631 microquasar candidate, 28 Mar 2007, 256 Mbps, Martí et al.
• Cyg X-3, 12-13 Jun 2007, 256 Mbps, Tudose et al.
• Stellar maser search, 22-23 Aug 2007, 32 Mbps, Langevelde et al.
• INTEGRAL source redo, 6-7 Sep 2007, 256 Mbps, Pandey et al.
• Type Ib/c SN 2007gr, 6-7 Sep 2007, 256 Mbps, Paragi et al.
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #9
First refereed journal papers:
GRS 1915+105: Rushton et al. (2007), MNRAS 374, L47
Cyg X-3: Tudose et al. (2007), MNRAS 375, L11
Cyg X-3
Aftermath of a huge outburst
-first detection of polarisation on
VLBI scales in a microquasar
What PI’s really need is to be able to
monitor these events in (1) closely spaced
monitoring observations, (2) when they
happen, not on fixed dates.
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #10
LSI 61+303 campaign:
• Binary XRB system, also source of very energetic gamma rays;
• What is the source of these? Earlier hypothesis: microquasar jet.
• Recent VLBA observations (Mioduszewski et al.) suggest an
interacting pulsar wind source instead
• MAGIC collaboration observations including e-EVN, VLBA, MERLIN, CHANDRA
in October 2006
The MAGIC telescope and a view of
its surroundings in La Palma. It is
capable of detecting very high energy
gamma rays.
The telescope is operated by the
MAGIC collaboration of 17 institutes
since 2004.
http://wwwmagic.mppmu.mpg.de/
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #11
…and the results
• no ultimate answer on the nature of the binary yet
• radio and X-rays originate from a different population
of electrons, but
• there is indication for temporal correlation between
X rays and gamma rays
Albert et al. (2008), Astrophys. J. (accepted),
astro-ph/0801.3150
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #12
IGR 17303-0601 results:
INTEGRAL source, with candidate
optical counterpart showing binary
nature, and associated(?) radio source
in NVSS.
e-VLBI confirms compactness, but measured
position is inconsistent with optical coords.
Not associated, radio source is not from
a microquasar jet – likely background AGN.
M. Pandey, Z. Paragi, P. Durouchoux,
H. Bignall, PoS(Dynamic2007)041
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #13
CHARA and e-VLBI observations of Algol
Algol is one of the most famous variable stars, also known as beta Persei.
It is very nearby, only 26 parsecs away,
ideal for optical/radio interferometry
studies.
Algol is active from radio to the X-ray
bands, besides the optical variations
due to regular eclipses.
Artist’s impression on the close binary system
from the web. The K-subgiant is the source of
radio activity.
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #14
The CHARA array
The CHARA array is located at Mount Wilson
in California, USA, and is operated by the
Center for High Angular Resolution for Astronomy
http://www.chara.gsu.edu/CHARA/
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #15
CHARA results
CHARA fringes before
and after processing.
Resulted visibility
amplitudes vs. baseline
length are shown below.
Fitted orbital parameters to the data,
found geometry of the system.
Determined distance: 26.1±0.4 pc,
Comparable or better accuracy than
HIPPARCOS!
Paragi et al., submitted to PoS
(Manchester MRU proceedings)
Csizmadia et al. (refereed paper in prep.)
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #16
Algol, 14 December 2006 e-EVN run:
+
• Simultaneous optical photometry and e-EVN obs.
(5 GHz, 256 Mbps) during secondary minimum
observations
of such
•Dedicated
Source flared
– total intensity
andflares
circular polarization
will be challenging
even forWSRT
e-VLBI
variations
consistent between
and e-EVN data
• Flare emission ~2 mas offset from the CP peak
• Detected proper motion during the
10 hours run –fitted orbital parameters
of the AB close binary, but…
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #17
Supernovae: and old story with e-EVN
• SN2001em was discovered on 15 September
2001 in UGC11794 galaxy (Pepenkova 2001).
Garrett et al. (2005)
• Redshift z~0.02 corresponding to a distance
of 80~Mpc.
• 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 emission
due 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
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #18
SN 2007gr ToO observations
• SN2007gr was discovered on 15 Aug 2007
with KAIT (CBET 1034); identified as
Type Ib/c.
• Distance is about 7.3 Mpc, 10x closer than
SN 2001em was.
• VLA discovers 610 microJy radio source
(Soderberg 2007)
• e-EVN observations: Da, Jb2, On, Tr, Wb
(256Mbps), at 6cm, on 2007 Sep 6-7
• Firm detection (5.6 ) of the supernova
within the VLA error box
Paragi et al. (2007), ATel #1215
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #19
The first
ATel message
from the
e-EVN
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #20
Science projects in 2008
• A number of exploratory runs
• Supernovae in IC694, member of the
famous Arp299 galaxy merger
system. PI Perez-Torres.
(MERLIN image from Antonis
Polatidis)
... record breaking correlaton job!
• On 8-9 April 2008, the first real
triggered observations: Cyg X-3 in
an X-ray states change.
• Followed by a huge outburst and
three ToO epochs, first e-EVN
observations outside the fixed dates.
• e-VLBI flexibility: could not do it
with disks because stations were
short of them!
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #21
Cyg X-3 giant flare (preliminary)
The Cyg X-3 puzzle; preliminary maps by the PI, Valeriu Tudose
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #22
What science would benefit from e-VLBI?
• Transients obviously, from quick
turnaround mostly
J1427+3312, z=6.12
• Surveys of a large sample of weak sources,
detection not 100% guaranteed (but likely)
1) can follow up quickly the detected
sources only, at other frequencies
2) big surveys not limited by recording
media capacity
• Projects requiring dynamic scheduling
• Others???, e.g. support to VSOP-2 Survey,
quick compactness check of highly
variable sources (also in size!) before
space VLBI observations?
• How could we best support X-ray and
gamma missions, for example GLAST?
2008 June 16-17
7th e-VLBI Workshop, Shanghai
The highest redshift radio-detected quasar, with
the EVN at 1.6 GHz - CSO at the edge of the
visible Universe! (Frey et al. 2008)
Slide #23
Synergy with other (e-)instruments
GLAST
• e-MERLIN will be complementary in
resolution to the e-EVN; short spacings
• LOFAR will be an exceptional instrument
for finding new transients
• Wide FoV focal plane array considered for
the WSRT - could also serve as a trigger
instrument
www.gsfc.nasa.gov
LOFAR (up)
and DIGESTIF
on the WSRT
(left); from
Astron web
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #24
Finishing thoughts...
• As Steven pointed out yesterday, e-VLBI is technologial pathfinder to
SKA.
• Specific developments in EXPReS definitely make the e-EVN an SKA
pathfinder.
• But do not think just the technology! We are looking for new ways of
doing VLBI research, especially in the area of transients, which could
soon transform our field considerably.
• e-EVN matured a great deal during the first two years of EXPReS, now
it is time to harvest the results.
• EXPReS eVSAG (e-VLBI Science Advisory Group) will address this
within a few days.
2008 June 16-17
7th e-VLBI Workshop, Shanghai
Slide #25