Hercules A

Hercules A
Radio-Optical View of the Galaxy Hercules A - Many thanks to: NASA, ESA, S. Baum and C. O'Dea (RIT), R. Perley and W. Cotton (NRAO/AUI/NSF), and the Hubble Heritage Team (STScI/AURA)

Sunday, June 17, 2012

Isolated type I spectra and duration versus frequency plots

I refer to: Sundaram and Subramanian 2005, Indian Institute of Astrophysics:


The Authors discuss the properties of isolated type I bursts.

Abstract: "Type I noise storms constitute a sizeable fraction of the active Solar radio emission component. Observations of isolated instances of such bursts, in the swept-frequency mode at metric wavelengths, have remained sparse, with several unfilled regions in the frequency coverage. Dynamic spectra of the burst radiation in the 30-130MHz band, obtained from the recently commissioned digital High Resolution Spectrograph at the Gauribidanur Radio Observatory, have unravelled in explicit detail the temporal and spectral profiles of isolated bursts thanks to the instrument's superior frequency and time resolution. Apart from presenting details of their fundamental emission features, the time- and frequency-profile symmetry, with reference to custom-specific Gaussian distributions, has been chosen as the nodal criterion to statistically explain the state of the source regions in the vicinity of magnetic reconnections, the latent excitation agent that contributes to plasma-wave energetics, and the quenching phenomenon that causes damping of the burst emission."

From their Fig. 3 shown below, the duration of type I isolated bursts is about 1 to 6 seconds at 40 MHz.

Tuesday, June 12, 2012

A discussion of type III radiation associated with the X3.9 flare on 031103

I refer to:

Chen, Qingrong; Petrosian, Vahé 2012, Stanford University:


The authors briefly discuss Type III radiation associated with the flare.

Abstract: "...Finally, we show that the electrons producing the upper coronal HXR source may very likely be responsible for the type III radio bursts at the decimetric/metric wavelength observed during the impulsive phase of this flare..."

Friday, June 8, 2012

Selected solar events on 120605 and 120607 at Paris Observatory

120605 events below

120607 events below

Many thanks to the Nancay Decametric Array Team at the Nancay Radio Astronomy Station of Paris Observatory

Wednesday, June 6, 2012

Extreme Ultra Violet jets, type III bursts, and sunspot waves

I refer to:
Innes Cameron Solanki 2011, Max-Planck Institut für Sonnensystemforschung:


The authors discuss a correlation of quasi periodic EUV jets observed on 100803 on Solar Dynamics Observatory 211 angstrom images and type III bursts observed in WIND WAVES dynamic spectra, 20 kHz to 13.6 MHz band. The EUV jets correlate with brightening at a small site on the edge of the sunspot umbra, and the brightening with 3-min sunspot intensity oscillations.

"...Conclusions: Active region EUV/X-ray jets and interplanetary electron streams originate on the edge of the sunspot umbra. They form along a current sheet between the sunspot open field and closed field connecting to underlying satellite flux. Sunspot running penumbral waves cause roughly 3-min jet footpoint brightening. The relationship between the waves and jets is less clear..."

M87 Radio Montage - National Radio Astronomy Observatory - F. Owen, J. Biretta and J. Eilek