Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.atnf.csiro.au/pub/people/jreynold/vlba/1622.ps.gz Äàòà èçìåíåíèÿ: Tue Oct 1 18:16:45 1996 Äàòà èíäåêñèðîâàíèÿ: Mon Dec 24 13:33:48 2007 Êîäèðîâêà: Ïîèñêîâûå ñëîâà: ñòîëîâàÿ ãîðà

VLBI PROPOSAL COVERSHEET
DEADLINES: 1st of Feb., June., Oct.
rcvd:
(1) Date Prepared: 29 September 1996
(2) Proposal Title: Correlation of the radio and fl \Gammaray intra­day variability in the For Grad Students
blazar PKS 1622­297 Only
Observations
(3) AUTHORS INSTITUTION/LOCATION For Ph.D. Anticipated
Thesis? Ph.D. Year
L. Kedziora­Chudczer RCfTA, University of Sydney yes 1997
D.L. Jauncey, M. Wieringa ATNF Epping
J. Reynolds, A. Tzioumis ATNF Epping
G. Nicolson HartRAO, RSA
M. Walker RCfTA, University of Sydney
(4) Related previous or current VLBI proposal(s):
(5) Contact author for scheduling: D. Jauncey c/­ COSSA
Telephone: +61 6 216­7220 Address: GPO Box 3023
E­Mail: djauncey@atnf.csiro.au Canberra 2601
Fax: +61 6 216­7222 AUSTRALIA
(6) Scientific Category (indicate all that apply):
fl astrometry & geodesy, fl solar, fl propagation, fl planetary, fl stellar, fl pulsar, fl ISM, fl masers,
fl normal galaxies,
N
active galaxies, fl cosmology
(7) Wavelength(s) requested (those not available on the global network are indicated with a small circle):
fl 90cm, fl 50cm, ffi 21cm, fl 18cm,
N
13cm, fl 6cm,
N
3.6cm, fl 3.6/13cm,
N
2cm, fl 1.3cm, fl 7mm
N
Global Network standard bands fl Special frequencies
(8) Recording format:
N
VLBA fl MkIV fl MkIII (Mode )
Aggregate bit rate 128 ( 4 BB channels at 16 MSamples/sec of fl 1 bit, N 2 bit samples)
(9)
N
Multi­epoch observation: 3 epochs of 9 hours each, separated by ¸3 days
(10) Network Requested antennas Total time requested
EVN
VLBA ALL 27
US
Unaffiliated
(11) ABSTRACT (Do not write outside this space. Please type.)
Scheduler use only
(09/96)
We propose multi­epoch imaging of the blazar PKS 1622--297 as part of a multi­waveband campaign to observe
this source over the period 11­18 February 1997. Results from the ATCA have shown this source to be a strong
intra­day variable, and multiple (3) epochs of VLBA imaging are requested to investigate the relationship between
the variability seen in this source from cm wavelengths to that in the higher energy bands, particularly at fl \Gammarays.

(12) Observation type:
N
Interferometry, fl Spectroscopy, fl Pulsar, fl Phase referencing, fl Single dish
(13) Polarization: fl IEEE RCP fl IEEE LCP
N
Dual Circular
Global network standard for single polarization is LCP for all –s except 13cm (RCP) and 3.6cm (RCP).
(14) Tape usage (Show !recording time?/!total time?): 9/9
(15) Assistance required:
Observation Setup: fl Consultation, fl Extensive help,
N
Control file preparation
Correlation: fl Consultation, fl Extensive help, fl Control file preparation
Postprocessing: fl Consultation, fl Extensive help, fl Control file preparation
(16) Processor: Socorro
Special processing:
N
XPol, fl Pulsar gate, fl Multiple Fields:
Averaging time: Spectral channels per baseband channel: 16
fl Other special processing:
(17) Postprocessing Location: ATNF
(18) Source list: N J2000 fl B1950
If more than 4 sources, please attach list. If more than 30, give only selection criteria and GST range(s)
Source 1 Source 2 Source 3 Source 4
Name(s) PKS 1622­297
RA (hh mm) 16 26
Dec (dd.d) ­29.9
GST range (Europe)
GST range (US) 19­04
GST range (Other)
Band(s) 13cm, 3.5cm, 2cm
Flux density (Total, Jy) ¸2Jy
Flux (correlated, mJy) ¸2Jy
RMS needed (mJy/beam) 5mJy
Peak/RMS needed ¸200:1
(19) Preferred VLBI session or range of dates for scheduling, and why:
11­18 February 1997 to coincide with scheduled CGRO/XTE observations
(20) Dates which are NOT acceptable, and why:
(21) Attach a self­contained scientific justification, not in excess of 1000 words.
Preprints or reprints will not be forwarded to the referees.
A brief description of the capabilities of the VLBA may be obtained by anonymous ftp from
ftp.aoc.nrao.edu (146.88.1.103 if you do not use a name server), file pub/obssum.vlba.ps. Or, if
you have the mosaic software available, use URL http://info.aoc.nrao.edu.
A brief description of the capabilities of the EVN may be obtained by ftp from astbo1.bo.cnr.it
(137.204.51.1 if you do not use a nameserver), login VLBINFO, file EVN.STS.
Please include the full addresses (postal and e­mail) for first­time users or for those that have
moved (if not contact author).

Correlation between radio and fl \Gammaray variability in the blazar PKS 1622­297
The blazar PKS 1622­297 was found to be the brightest GeV fl­ray source in the sky in 1995 and
showed intra­day fl­ray variability (J. Mattox, http://bu­ast.bu.edu/ mattox/1622/). A successful proposal
has been submitted for CGRO/XTE observations of PKS 1622­297 over the period 11­18 February 1997. In
addition, proposals have been submitted for ASCA X­ray observations during this interval, as well as for IR
observations with ISO, 4­frequency flux­monitoring with the ATCA, and for mm­wavelength observations
with the James Clerk Maxwell telescope.
We propose here for 3 epochs of VLBI imaging during the same period to monitor structural changes
within the source associated with the intra­day variability.
This source has been found to be a long­term variable at cm wavelengths, based on monitoring at
HartRAO. More recently, monitoring with the ATCA has shown intra­day variability, with amplitude changes
of up to 10% within 2 days. The amplitude of the variability increases with observing frequency up to 8.6GHz,
and we therefore request imaging at 3.6cm and 2cm to determine spectral index distributions of the fixed
and variable source components. We will also observe at 13cm during one of the three sessions to image the
larger scale structure of the source.
The existing long­term monitoring at HartRAO, where observations are made on a weekly basis, will
determine the long­term variability of this source, while the very high precision achievable with the ATCA
allow the detection of even very low­level IDV. The addition of HARTRAO to the monitoring program also
allows almost full 24­hour coverage of the source at the two shorter wavelengths. The value of this has
been well demonstrated in our observations of the strong variability of PKS 0405­385, where the ATCA and
HartRAO observations match extremely well in the overlap region (Kedziora­Chudczer et al., in preparation).
Our ATCA observations of IDV in the quasar PKS 0405­385 suggest that the variations in that source
arise from scintillation in the Galactic interstellar medium. For PKS 1622­297 however, the detection of IDV
in the fl \Gammaray band strongly suggests that the variations are intrinsic to the source. How these variations may
be produced is far from clear at present, but we expect that the multi­waveband observations of this proposed
campaign will provide important clues to the mechanism and constrain existing models. In particular, one
expects a fundamental microphysical link between the high energy and radio bands -- the X­ and fl­rays may
arise from up­scattering of photons by the same relativistic electrons responsible for the radio synchrotron
emission.