SIMBAD references

We report high time-resolution broadband spectroscopic observations of two radio bursts on the classical flare star AD Leonis. The observations were acquired by the 305 m telescope at Arecibo Observatory on 2003 June 13-14. Using the Wideband Arecibo Pulsar Processor, these observations sampled a total bandwidth of 400 MHz, distributed over a 500 MHz frequency range, 1120-1620 MHz, with a frequency resolution of 0.78 MHz and a time resolution of 10 ms. The radio burst observed on June 13 is characterized by the presence of multitudes of short-duration (Δt∼30 ms), high brightness temperature (T_b>10¹⁴ K), highly circularly polarized, fast-drift radio sub-bursts, with median bandwidths Δν/ν∼5%. The inverse drift rates are small and have a symmetric distribution (both positive and negative frequency drifts), with a Gaussian FWHM inverse drift rate of 4.5x10^–4 s/MHz. The fast-drift sub-bursts occur at a mean rate of 13/s and show no evidence for periodic recurrence. The fast-drift radio events on AD Leo are highly reminiscent of solar decimetric spike bursts. We suggest that the emission is due to fundamental plasma radiation. A second highly circularly polarized radio burst, recorded June 14, has markedly different properties: a smoothly varying intensity profile characterized by a slow drift in frequency with time (-52 MHz/s). Under the assumption that the source is due to a disturbance propagating through the low corona, a source size of 0.1-1 R_*is inferred, implying a brightness temperature range 6x10¹¹-6x10¹³ K; another example of a coherent radio burst.