J/MNRAS/369/449 PKS 0405-385 flux-density monitoring (Kedziora-Chudczer+, 2006)
Long-term monitoring of the intra-day variable quasar PKS 0405-385.
Kedziora-Chudczer L.
<Mon. Not. R. Astron. Soc., 369, 449-464 (2006)>
=2006MNRAS.369..449K 2006MNRAS.369..449K
ADC_Keywords: QSOs ; Polarization ; Radio sources
Keywords: scattering - turbulence - quasars: jets - radio continuum: ISM
Abstract:
The quasar PKS 0405-385 is one of three radio sources (the other two
are PKS 1257-326 and J1819+385) which exhibit unusually strong and
rapid interstellar scintillations at GHz frequencies. Such a behaviour
suggests a nearby (<30pc away) scattering screen along the line of
sight to these radio sources. While quasars PKS 1257-326 and J1819+385
scintillate continuously over several years of monitoring,
PKS 0405-385 shows episodes of strong scintillations which last only a
few months. Here, I present the results of flux-density monitoring of
PKS 0405-385 over 6yr at four Stokes parameters and four frequencies.
Two explanations of the episodic behaviour of interstellar
scintillation in this source are discussed; morphological evolution of
the source and changes in the properties of the interstellar medium
along the line of sight.
Description:
The monitoring of PKS 0405-385 commenced in 1993 November, as part of
the ATCA IDV Survey (Kedziora-Chudczer et al., 2001, Cat.
J/MNRAS/325/1411) with the Australia Telescope Compact Array.1 The
source showed rapid variability in total flux density at 8.6, 4.8 and
2.4GHz during these observations. The time-scale of variability,
defined throughout this paper as HWHP of auto-correlation function of
flux density, was faster than 2h (the frequency of sampling used in
the survey).
Objects:
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RA (2000) DE Designation(s)
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04 06 59.0 -38 26 28 PKS 0405-385 = QSO B0405-385
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 74 230 Average flux densities and modulation indices at the
four frequencies obtained for each observing session
during the long-term monitoring of PKS 0405385
table3.dat 86 33 *Average linear and circular polarisation obtained
during the long-term monitoring of PKS 0405-385
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Note on table3.dat:
The data from observing sessions longer than 3h are included in the
table. Shorter observations have inadequate coverage of the parallactic
angle, which is needed for adequate polarization calibration.
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See also:
J/MNRAS/325/1411 : ATCA Intraday Variability Survey (Kedziora-Chudczer+, 2001)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "YYYY/MM/DD" ObsDate Observation date
12- 15 F4.1 h OL8.6 Observation length at 8.6GHz
17- 20 F4.1 h OL4.8 Observation length at 4.8GHz
22- 25 F4.1 h OL2.4 Observation length at 2.4GHz
27- 30 F4.1 h OL1.4 Observation length at 1.4GHz
32- 35 F4.2 Jy S8.6 Average flux density at 8.6GHz
37- 40 F4.2 Jy S4.8 Average flux density at 4.8GHz
42- 45 F4.2 Jy S2.4 Average flux density at 2.4GHz
47- 50 F4.2 Jy S1.4 Average flux density at 1.4GHz
52- 56 F5.3 --- MI8.6 Modulation index at 8.6GHz
58- 62 F5.3 --- MI4.8 Modulation index at 4.8GHz
64- 68 F5.3 --- MI2.4 Modulation index at 2.4GHz
70- 74 F5.3 --- MI1.4 Modulation index at 1.4GHz
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "YYYY/MM/DD" ObsDate Observation date
12- 16 F5.3 Jy PolL8.6 Linear polarization at 8.6GHz
18- 22 F5.1 deg PA8.6 [-90/90] Position angle at 8.6GHz
24- 28 F5.3 Jy PolL4.8 Linear polarization at 4.8GHz
30- 34 F5.1 deg PA4.8 [-90/90] Position angle at 4.8GHz
36- 40 F5.3 Jy PolL2.4 Linear polarization at 2.4GHz
42- 46 F5.1 deg PA2.4 [-90/90] Position angle at 2.4GHz
48- 52 F5.3 Jy PolL1.4 Linear polarization at 1.4GHz
54- 58 F5.1 deg PA1.4 [-90/90] Position angle at 1.4GHz
60- 65 F6.3 Jy PolC8.6 Circular polarization at 8.6GHz
67- 72 F6.3 Jy PolC4.8 Circular polarization at 4.8GHz
74- 79 F6.3 Jy PolC2.4 Circular polarization at 2.4GHz
81- 86 F6.3 Jy PolC1.4 Circular polarization at 1.4GHz
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 19-Jan-2007