2007A&A...463..567P


C.D.S. - SIMBAD4 rel 1.7 - 2019.08.22CEST10:15:18

2007A&A...463..567P - Astronomy and Astrophysics, volume 463, 567-577 (2007/2-4)

Low-frequency radio monitoring of microquasars.

PANDEY M., RAO A.P., ISHWARA-CHANDRA C.H., DUROUCHOUX P. and MANCHANDA R.K.

Abstract (from CDS):

Microquasars are radio-emitting X-ray binaries (REXBs) with a radio morphology like quasars and high X-ray luminosity. Sixteen known microquasar candidates were extensively monitored for the first time at low radio frequencies using the Giant Meter-wave Radio Telescope (GMRT) between 6-June 2003 and 22-Jan. 2005 at 0.235/0.61 (simultaneous) and 1.28GHz. Nine out of sixteen sources were detected positively by the GMRT including all six high-mass X-ray binaries (HMXBs) and three low-mass X-ray binaries (LMXBs). Among the nine sources emitting at low frequencies, six are persistent in radio and three are transient at radio wavelengths. In the case of four persistent radio sources (Scorpius X-1, Cyg X-1, Cyg X-3, and LSI+61303) the contemporaneous data suggests a spectral turnover (Sνα, α>0) and agrees with the synchrotron self absorption (SSA) effect expected at lower frequencies. The radio spectra of SS433 and LS5039 show a power law decay (Sνα, α<0) with no signature of SSA even at the very low frequency of 0.235GHz. This unique result suggests either that these sources are scatter-broadened at lower frequencies or that the low-frequency radio emission from these sources are superimposed by the emission from an extended region located near these sources. Five sources, GRO J1655-40, XTE J1118+480, 1E1740.7-2942, XTE J1748-288, and GRS 1758-258 were never detected during our observations, thus suggesting that they show the SSA effect at lower frequencies or that they are too faint to be detected at GMRT frequencies. Because interstellar scintillation becomes dominant at low frequencies and may lead to flux-density fluctuations, the scintillation time scale for each microquasar was calculated and compared to the variability time scale in the data. We confirm from these studies that Cyg X-1 and SS433 are most likely affected by scintillation and that LSI+61303, LS 5039, Sco X-1, and XTE J1118+480 may possibly be affected by scintillation. A comparative study of the radio luminosity from centimeter-(GHz) to meter-wavelength (MHz) suggests a decrease by a few orders of magnitude as one goes lower in frequency. We have also plotted the RXTE/ASM X-ray light curve for all the sixteen known microquasars. Based on the ASM data, the X-ray light curve can be classified as: (a) persistent, (b) quasi-persistent or (c) transient. From the analysis of these types and the information about their companion star, the persistent or transient nature of the radio jet can be confirmed. This paper provides a general review of the main observational results obtained up to now, as well as different models for the production of low-frequency radio emissions from these sources.

Abstract Copyright:

Journal keyword(s): radiation mechanisms: non-thermal - acceleration of particles - instrumentation: interometers - methods: observational - binaries: general - ISM : jets and outflows

Simbad objects: 22

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Number of rows : 22

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 3C 48 QSO 01 37 41.2995845985 +33 09 35.079126038   16.62 16.20     ~ 2418 2
2 LS I +61 303 HXB 02 40 31.6641883136 +61 13 45.591138110 11.27 11.61 10.75 10.19 9.55 B0Ve 746 2
3 V* KV UMa HXB 11 18 10.7922353051 +48 02 12.319175505     12.25     K5V-M1V 702 0
4 3C 286 Sy1 13 31 08.2885060664 +30 30 32.960825108   17.51 17.25     ~ 3592 1
5 V* BR Cir HXB 15 20 40.85 -57 10 00.1   21.4 21.4     ~ 707 1
6 V* V381 Nor HXB 15 50 58.6520652623 -56 28 35.309070422   17.95 16.6     K3III 991 0
7 V* V818 Sco LXB 16 19 55.0688745859 -15 38 25.019920749 11.60 12.40 11.1     Oev 1510 0
8 V* V1033 Sco HXB 16 54 00.137 -39 50 44.90   15.20 14.2 16.14   F5IV 1659 1
9 V* V821 Ara HXB 17 02 49.3810714542 -48 47 23.163091737 16.20 16.30 15.5     ~ 1691 0
10 V* V2731 Oph DQ* 17 30 21.50 -05 59 33.5           ~ 70 0
11 NAME Great Annihilator LXB 17 43 54.83 -29 44 42.6           ~ 634 1
12 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 10884 0
13 AX J1748.0-2829 LXB 17 48 05.060 -28 28 25.80           ~ 164 0
14 2XMM J180112.4-254436 LXB 18 01 12.40 -25 44 36.1           ~ 357 1
15 V* V4641 Sgr HXB 18 19 21.6342721789 -25 24 25.849323550     13.654   13.092 B9III 372 1
16 V* V479 Sct HXB 18 26 15.0561532140 -14 50 54.249464136 12.02 12.23 11.27 11.04   ON6V((f))z 481 2
17 IGR J18406-0539 Em* 18 40 47.0 -05 40 51     10.8     ~ 14 2
18 SS 433 HXB 19 11 49.5645897701 +04 58 57.824087535   16.3 13.0     A7Ib: 1893 3
19 Granat 1915+105 LXB 19 15 11.54938 +10 56 44.7585           ~ 2218 0
20 HD 226868 HXB 19 58 21.6758193269 +35 12 05.782512305 9.38 9.72 8.91 8.42   O9.7Iabpvar 3832 0
21 V* V1521 Cyg HXB 20 32 25.78 +40 57 27.9           WN4/5-6/7 1734 2
22 Ass Cyg OB 2 As* 20 33.2 +41 19           ~ 745 0

    Equat.    Gal    SGal    Ecl

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2019.08.22-10:15:18

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