Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.atnf.csiro.au/iau-comm31/pdf/2009_IAUGA_JD6/JD6_3_8_Ilyasov.pdf Дата изменения: Fri Aug 6 03:07:04 2010 Дата индексирования: Mon Feb 4 07:42:53 2013 Кодировка: Поисковые слова: corona

Yu. Ilyasov1., V. Zharov 2., M. Sekido3
1 2 3

- Pushchino Radio Astronomical Observatory of Lebedev Inst. (Russia) - Sternberg State Astronomical Institute of Moscow St. University (Russia) - Kashima Space Research Center of NICT (Japan)


Pulsars generating Giant Radio Pulses Main PSR with GRPs
PSR name J0218+4232 J0534+2200 J1939+2134 J1959+2048 02:18:06.35 05:34:31.97 19:39:38.55 19:59:36.76 +42:32:17.43 +22:00:52.06 +21:34:59.13 +20:48:15.12 RA DEC P ms 2,323 33,084 1,557 1,607 S1400 mJy 0,9 14 10 0,4 W50 ms * 3,0 0,063 0,035 DM Pc.cm61,2 56,79 71,03 29,11
3

R kpc 5.85 2.00 8.33 1.53

Main References
1. Ilyasov Yu., Kuzmin A., Smirnova T., Fedorov Yu. // Pat. No 1669301 Date-08.09.1991. Bull VNIIRI No 11 (Priority 04.07.1988) 2. Cognard I.,Shrauner J.A., Taylor J.H. and Thorsett S.E.//Astron .Jour. 1996, v.457, L81-L84. 3. Ilyasov Yu. , Oreshko V., Popov M., Soglasnov V. // Proceeding of the IAA RAS 2007, v. 17, p.128-137.


GRP 0531+21 ("Crab")
(2005, Kalyazin, at 1400 & 2200 Hz)
kJy kJy

micro sec

micro sec

1400 Hz

2200 Hz


v

Time (nanosecond)

T.H.Hankins, J.A.Eilek Radio emission signatures in the Crab pulsar. 40 Years of Pulsars: McGill conference 2007 . http://www.ns2007.org


Physics of the Giant Radio Pulses
Duration 0.4 ns implies source size about 12 cm Peak power is 10% of total power from the Sun Equivalent brightness temperature is about 2 x 1041K (assuming stationary emitter) Multiple, frequency dependent components Bandwidth: Wide Average pulse polarization: - Main pulse: weak or random - Interpulse: 100% linear at high frequencies
T.H.Hankins, J.A.Eilek Radio emission signatures in the Crab pulsar. 40 Years of Pulsars: McGill conference 2007 . http://www.ns2007.org


Giant Pulse Statistics and peak power of J0534+2200 (Kalyazin monitoring) FREQUENCY
GHz

Flux Sp
Jy

eak

Number GRP N (per hour)
6

0,6
4 ,8 5

> (0,3 - 1,0)10 > 10
4

6-7 2-3


Radio Telescope -64
(-1500 SRB MPEI, Kalyazin)

Main reflector diameter 64 m Secondary reflector diameter 6m RMS (surface) 0.7 mm Feed ­ Horn (wideband) 5.2 x 2.1 m Frequency range 0.5 ­ 15 GHz Antenna noise temperature 20K Total Efficiency (through range) 0.6 Slewing rate 1.5 deg/sec Receivers for frequency: 0.6; 1.4; 1.8; 2.2; 4.9; 8.3 GHz


COHERENT "DISPERSION REMOVER"
eVLBI- K5
RHCP

FFT
S(t ) H ( f )

CONVOLUTION

LHCP

K5/VSSP Multi-bit Sampler Recording System to HDD

H ( f ) = H ( f ) -1 ( f )
*

-

-1 ( f ) : Inverse of Dispersion
Transfer Function

1PPS

10 MHz H-maser Ref. clock

H * ( f ) S* (t )

IFFT

GRP


IP ­ VLBI K-5 ­ at Kalyazin


Kalyazin R ­ 64

Kashima R- 34

KALYAZIN KASHIMA


Clocks comparison by VLBI
d= C

ionosphere troposphere

rrr B = R -R 12
1
r R 1

2

R1

r R

2

rr d = c = S · B
B - baseline vector S - unit vector to the radio source

T2 = T1 -

Estimation of



by least square analysis


Giant Radio Pulses of PSR as a Tool for Time comparison to PSR

Giant Radio Pulses (GRP) are observed simultaneously at each station Precise Time of Arrival of Giant Pulses are measured at each observatory. Since occurrence of GRP could be identified without ambiguity, difference of TOA of GRP can be used for time comparison.


Advantages of Time Comparison with Giant Radio Pulses
Very small amount of data is enough to be exchanged for time comparison.
e.g. VLBI needs a TB of Data to be transferred for one 24hour experiments.)

Time comparison at multiple stations can be easily realized. Operational cost will be much less than TWSTT


ERROR BUDGET of CLOCKS COMPARISON by GRP (Distance 10 000 km, basic contributions)
FACTOR Reference PSR position Coordinates 0f clock stations Earth pole position Timing measurement accuracy Time delay in space: ionosphere troposphere Total summary 2 ns@1.4GHz, 0.06ns@8.4GHz 0.15 ns -2 0.06 0.15 2@1.4GHz 0.25@8.4GHz ACCURACY 0.001 arc. sec 1 cm 1 cm 0.1 ns TIME ERROR (RMS ) ns 0.16 0.03 0.03 0.1


DIFFERENT TECHNIQUES OF CLOCKS COMPARISON
TECHNIQUE METEORS TRACE RADAR* TV ­
CHANNELS *

DISTANCE km 500 -1500 50 -200 1000 ­ 16 000 1000 - 2000 100 ­ 12 000 1000 ­ 12 000 1000 ­ 12 000 (in Space too) 100-8000

RMS ns 500 - 1000 100 - 500 10 - 50 500 - 1000 1 - 10 0.01 ­ 0.1 0.2 ­ 2.0 0.5

TRANSPORTED Cs CLOCK * LORAN ­ C * GPS,* GLONASS INTERCONTINENTAL VLBI * GIANT RADIO PULSES of PSR Two-way Satellite Time Transfer (TWSTT)

* C.Audoin, B.Guinot. "Les Fondements de la Mesure du Temps" Paris, Masson. 1998


GRP 0531+21 («Crab»).
Simultaneous detection of GRP in 2006 at Kalyazin (Russia) - RT-64 & Algonquin- Park (Canada) - RT-47 DAS VLBI - S2 at 2.2 GHz ( f ­ 32 MHz)

GRP peak about 600 Jy with a microstructure in single pulse before GRP Ilyasov Yu. , Kondratiev V., Oreshko V., Popov M., Soglasnov V. easurement Technique (Russia) 2009, No 8 (in press)


CONCLUSION
1. 2. 3. 4.

5. 6.

A fine structure of individual pulses of several pulsars contents a huge radiation splash about 1 ns duration. A flux density of such Gigantic Radio Pulse (GRP ) are about MJy. The most strong GRPs of the Crab pulsar B0531+ 21 are detected about 5-6 times per hour. Coherent mechanism of GRP radiation is now under study. Proposed application the GRP for precise comparison of distant clocks is prominent. It could be use just in real time with accuracy a little worse then VLBI technique, but without any transportation of high frequency VLBI station data observation to correlation center. Technique of precise calculations of time delay propagation to each clock, that is made for VLBI observation, ought to be used for clocks comparison in the same way as for VLBI. Short cm wavelengths are preferable for clocks comparison by GRP.
The investigations are supported by RFBR Grants: 04-02-16384 06-02-16816.


THANK YOU FOR ATTENTION !