skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Structure in the Radio Counterpart to the 2004 Dec 27 Giant Flare From SGR1806-20

Abstract

The formation of an expanding, moving, and fading radio source. We report observations of this radio source with the Multi-Element Radio-Linked Interferometer Network (MERLIN) and the Very Long Baseline Array (VLBA). The observations confirm the elongation and expansion already reported based on observations at lower angular resolutions, but suggest that at early epochs the structure is not consistent with the very simplest models such as a smooth flux distribution. In particular there appears to be significant structure on small angular scales, with {approx}10% of the radio flux arising on angular scales <= 100 milliarcsec. This structure may correspond to localized sites of particle acceleration during the early phases of expansion and interaction with the ambient medium.

Authors:
; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
878012
Report Number(s):
SLAC-PUB-11623
Journal ID: ISSN 0035-8711; MNRAA4; astro-ph/0511214; TRN: US200609%%13
DOE Contract Number:
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Monthly Notices of the Royal Astronomical Society; Journal Volume: 367
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COSMIC RADIO SOURCES; STELLAR FLARES; MORPHOLOGY; INTERFEROMETERS; Astrophysics,ASTRO

Citation Formats

Fender, Rob P., Muxlow, T.W.B., Garrett, M.A., Kouveliotou, C., Gaensler, B.M., Garrington, S.T., Paragi, Z., Tudose, V., Miller-Jones, J.C.A., Spencer, R.E., Wijers, R.A.M., Taylor, G.B., and /Southampton U. /Jodrell Bank /JIVE, Dwingeloo /NASA, Marshall /Harvard-Smithsonian Ctr. Astrophys. /Amsterdam U., Astron. Inst. /Astron. Inst. Romanian Acad. /KIPAC, Menlo Park /NRAO, Socorro /New Mexico U. Structure in the Radio Counterpart to the 2004 Dec 27 Giant Flare From SGR1806-20. United States: N. p., 2006. Web.
Fender, Rob P., Muxlow, T.W.B., Garrett, M.A., Kouveliotou, C., Gaensler, B.M., Garrington, S.T., Paragi, Z., Tudose, V., Miller-Jones, J.C.A., Spencer, R.E., Wijers, R.A.M., Taylor, G.B., & /Southampton U. /Jodrell Bank /JIVE, Dwingeloo /NASA, Marshall /Harvard-Smithsonian Ctr. Astrophys. /Amsterdam U., Astron. Inst. /Astron. Inst. Romanian Acad. /KIPAC, Menlo Park /NRAO, Socorro /New Mexico U. Structure in the Radio Counterpart to the 2004 Dec 27 Giant Flare From SGR1806-20. United States.
Fender, Rob P., Muxlow, T.W.B., Garrett, M.A., Kouveliotou, C., Gaensler, B.M., Garrington, S.T., Paragi, Z., Tudose, V., Miller-Jones, J.C.A., Spencer, R.E., Wijers, R.A.M., Taylor, G.B., and /Southampton U. /Jodrell Bank /JIVE, Dwingeloo /NASA, Marshall /Harvard-Smithsonian Ctr. Astrophys. /Amsterdam U., Astron. Inst. /Astron. Inst. Romanian Acad. /KIPAC, Menlo Park /NRAO, Socorro /New Mexico U. Wed . "Structure in the Radio Counterpart to the 2004 Dec 27 Giant Flare From SGR1806-20". United States. doi:. https://www.osti.gov/servlets/purl/878012.
@article{osti_878012,
title = {Structure in the Radio Counterpart to the 2004 Dec 27 Giant Flare From SGR1806-20},
author = {Fender, Rob P. and Muxlow, T.W.B. and Garrett, M.A. and Kouveliotou, C. and Gaensler, B.M. and Garrington, S.T. and Paragi, Z. and Tudose, V. and Miller-Jones, J.C.A. and Spencer, R.E. and Wijers, R.A.M. and Taylor, G.B. and /Southampton U. /Jodrell Bank /JIVE, Dwingeloo /NASA, Marshall /Harvard-Smithsonian Ctr. Astrophys. /Amsterdam U., Astron. Inst. /Astron. Inst. Romanian Acad. /KIPAC, Menlo Park /NRAO, Socorro /New Mexico U.},
abstractNote = {The formation of an expanding, moving, and fading radio source. We report observations of this radio source with the Multi-Element Radio-Linked Interferometer Network (MERLIN) and the Very Long Baseline Array (VLBA). The observations confirm the elongation and expansion already reported based on observations at lower angular resolutions, but suggest that at early epochs the structure is not consistent with the very simplest models such as a smooth flux distribution. In particular there appears to be significant structure on small angular scales, with {approx}10% of the radio flux arising on angular scales <= 100 milliarcsec. This structure may correspond to localized sites of particle acceleration during the early phases of expansion and interaction with the ambient medium.},
doi = {},
journal = {Monthly Notices of the Royal Astronomical Society},
number = ,
volume = 367,
place = {United States},
year = {Wed Jan 11 00:00:00 EST 2006},
month = {Wed Jan 11 00:00:00 EST 2006}
}
  • The authors use the relativistic hydrodynamics code Cosmos++ to model the evolution of the radio nebula triggered by the Dec. 27, 2004 giant flare event of soft gamma repeater 1806-20. They primarily focus on the rebrightening and centroid motion occurring subsequent to day 20 following the flare event. They model this period as a mildly relativistic ({gamma} {approx} 1.07-1.67) jetted outflow expanding into the intergalactic medium (IGM). They demonstrate that a jet with total energy {approx} 10{sup 46} ergs confined to a half opening angle {approx} 20{sup o} fits the key observables of this event, e.g. the flux lightcurve, emissionmore » map centroid position, and aspect ratio. In particular, they find excellent agreement with observations if the rebrightening is due to the jet, moving at 0.5 c and inclined {approx} 0{sup o}-40{sup o} toward the observer, colliding with a density discontinuity in the IGM at a radius of several 10{sup 16} cm. They also find that a jet with a higher velocity, {approx}> 0.7c, and larger inclination, {approx}> 70{sup o}, moving into a uniform IGM can fit the observations in general, but tends to miss the details of rebrightening. The latter, uniform IGM model predicts an IGM density more than 100 times lower than that of the former model, and thus suggests an independent test which might discriminate between the two. One of the strongest constraints of both models is that the data seems to require a non-uniform jet in order to be well fit.« less
  • On 27 December 2004, a giant {gamma} flare from the Soft Gamma-Ray Repeater 1806-20 saturated many satellite gamma-ray detectors, being the brightest transient event ever observed in the Galaxy. AMANDA-II was used to search for down-going muons indicative of high-energy gammas and/or neutrinos from this object. The data revealed no significant signal, so upper limits (at 90% C.L.) on the normalization constant were set: 0.05(0.5) TeV{sup -1} m{sup -2} s{sup -1} for {gamma}=-1.47 (-2) in the gamma flux and 0.4(6.1) TeV{sup -1} m{sup -2} s{sup -1} for {gamma}=-1.47 (-2) in the high-energy neutrino flux.
  • On 2004 Dec. 27, a giant {gamma}-ray flare was detected from the magnetar SGR 1806-20. A radio observation seven days later revealed an expanding radio nebula at this position. Here we present results from an on-going monitoring campaign of this source with the Australia Telescope Compact Array and Very Large Array. These data indicate that there was an increase in the observed flux ?25 days after the initial {gamma}-ray flare that lasted for {approx}3-5 days. In this Letter, we argue that this rebrightening marks the end of the coasting phase of the blast wave and the transition to the Sedov-Taylormore » phase. Assuming a distance to SGR 1806-20 of 15 kpc, we infer from the properties of this rebrightening that the blast wave is baryonic material of mass M {approx}> 10{sup 24.5} g. In an accompanying paper (Granot et al. 2005), we show that this material was initially expanding with a velocity of about 0.4c; we therefore infer a kinetic energy E {approx}> 10{sup 44.5} ergs. If this mass was blown off the outer layers of the magnetar, it may have emitted a burst of ultra-high energy (E > 1 TeV) neutrinos far in excess of what might be expected from other astrophysical sources.« less
  • The multi-wavelength observations of the 2004 December 27 Giant Flare (GF) from SGR 1806-20 and its long-lived radio afterglow are briefly reviewed. The GF appears to have been produced by a dramatic reconfiguration of the magnetic field near the surface of the neutron star, possibly accompanied by fractures in the crust. The explosive release of over 10{sup 46} erg (isotropic equivalent) powered a one-sided mildly relativistic outflow. The outflow produced a new expanding radio nebula, that is still visible over a year after the GF. Also considered are the constraints on the total energy in the GF, the energy andmore » mass in the outflow, and on the external density, as well as possible implications for short {gamma}-ray bursts and potential signatures in high energy neutrinos, photons, or cosmic rays. Some possible future observations of this and other GFs are briefly discussed.« less
  • With frequent flaring activity of its relativistic jets, Cygnus X-3 (Cyg X-3) is one of the most active microquasars and is the only Galactic black hole candidate with confirmed high-energy γ-ray emission, thanks to detections by Fermi Large Area Telescope (Fermi/LAT) and AGILE. In 2011, we observed Cyg X-3 in order to transit to a soft X-ray state, which is known to be associated with high-energy γ-ray emission. We present the results of a multiwavelength campaign covering a quenched state, when radio emission from Cyg X-3 is at its weakest and the X-ray spectrum is very soft. A giant (~20more » Jy) optically thin radio flare marks the end of the quenched state, accompanied by rising non-thermal hard X-rays. Fermi/LAT observations (E≥ 100 MeV) reveal renewed γ-ray activity associated with this giant radio flare, suggesting a common origin for all non-thermal components. In addition, current observations unambiguously show that the γ-ray emission is not exclusively related to the rare giant radio flares. A three-week period of γ-ray emission is also detected when Cyg X-3 was weakly flaring in radio, right before transition to the radio quenched state. There were no γ-rays observed during the ~1-month long quenched state, when the radio flux is weakest. These results suggest transitions into and out of the ultrasoft X-ray (radio-quenched) state trigger γ-ray emission, implying a connection to the accretion process, and also that the γ-ray activity is related to the level of radio flux (and possibly shock formation), strengthening the connection to the relativistic jets.« less