An evaporating black hole in the presence of an extra spatial dimension would undergo an explosive phase of evaporation. We show that such an event, involving a primordial black hole, can produce a detectable, distinguishable electromagnetic pulse, signaling the existence of an extra dimension of size L ∼ 10 −18 − 10 −20 m. We derive a generic relationship between the Lorentz factor of a pulse-producing "fireball" and the TeV energy scale. For an ordinary toroidally compactified extra dimension, transient radio-pulse searches probe the electroweak energy scale (∼0.1 TeV), enabling comparison with the Large Hadron Collider.

We report the detection of giant pulse emission from PSR B0950+08 in 24 hours of observations made at 39.4 MHz, with a bandwidth of 16 MHz, using the first station of the Long Wavelength Array, LWA1. We detected 119 giant pulses from PSR B0950+08 (at its dispersion measure), which we define as having SNRs at least 10 times larger than for the mean pulse in our data set. These 119 pulses are 0.035% of the total number of pulse periods in the 24 hours of observations. The rate of giant pulses is about 5.0 per hour. The cumulative distribution of pulse strength S is a steep power law, N (> S) ∝ S −4.7 , but much less steep than would be expected if we were observing the tail of a Gaussian distribution of normal pulses. We detected no other transient pulses in a dispersion measure range from 1 to 90 pc cm −3 , in the beam tracking PSR B0950+08. The giant pulses have a narrower temporal width than the mean pulse (17.8 ms, on average, vs. 30.5 ms). The pulse widths are consistent with a previously observed weak dependence on observing frequency, which may be indicative of a deviation from a Kolmogorov spectrum of electron density irregularities along the line of sight. The rate and strength of these giant pulses is less than has been observed at ∼100 MHz. Additionally, the mean (normal) pulse flux density we observed is less than at ∼100 MHz. These results suggest this pulsar is weaker and produces less frequent giant pulses at 39 MHz than at 100 MHz.for gravitational-wave events, triggered by the detection of radio transients. The benefits of such collaborative work will be described in another publication.We would like to acknowledge insightful discussions with S.W. Ellingson, T.J.W. Lazio and P. S. Ray.

We present meter-wave solar radio spectra of the highest spectro-temporal resolution achieved to date. The observations, obtained with the first station of the Long Wavelength Array (LWA1), show unprecedented detail of solar emissions across a wide bandwidth during a Type-III/IIIb storm. Our flux calibration demonstrates that the LWA1 can detect Type-III bursts much weaker than 1 SFU, much lower than previous observations, and that the distribution of fluxes in these bursts varies with frequency. The high sensitivity and low noise in the data provide strong constraints to models of this type of plasma emission, providing evidence against the idea that Type-IIIb striae are generated from electrons trapped in Langmuir wave sidebands. The continuous generation of electron beams in the corona revealed by the high density Type-III storm is evidence for ubiquitous magnetic reconnection in the lower corona. Such an abundance of reconnection events not only contributes to the total coronal energy budget, but also provides an engine by which to form the populations of seed particles responsible for proton-rich solar energetic particle events. An active region (AR) with such levels of reconnection and the accompanying Type-III/IIIb storms is here proposed to be associated with an increase of SEP production if a CME erupts. The data's constraints on existing theories of Type-IIIb production are used to make an association of the observed Type-IIIb storm to specific electron beam paths with increased inhomogeneities in density, temperature, and/or turbulence. This scenario ties in the observed timing of Type-III and IIIb storms, constrained theories of Type-III and IIIb emission, and the ability of the emitting AR to produce a strong SEP event. The result requires but a single observable to cement these ideas, the statistical correlation of Type-III/IIIb activity with SEP-productive AR.

The study of anomalous longitudinal profiles of extensive air showers presents an interesting opportunity to gain additional insight about the character of hadronic interactions at the highest energies. Moreover, the presence of such profiles would represent direct evidence of a light component in the primary cosmic rays of a given energy, independently of hadronic interaction models. The ratio of profiles observed to have a "double bump" structure (with two clearly distinguishable atmospheric depths of maximum particle count) compared to the total number of events can moreover be used to test the predictions of interaction models. However, the majority of such profiles observed at the Pierre Auger Observatory are caused by clouds. Here we describe a method of rapid monitoring of particularly interesting cosmic ray events, using the F/Photometric Rapid Atmospheric Monitor (FRAM) telescope to identify events with clear, cloudless atmospheric background. The function of FRAM is described in detail and the number of triggered events is presented.

An exploding primordial black-hole (PBH) may produce a single pulse of electromagnetic radiation detectable at the low-frequency end of the radio spectrum. Furthermore, a radio transient from an exploding PBH could be a signature of an extra spatial dimension. We describe here an approach for searching for PBH explosions using a lowfrequency radio antenna array, and as a practical example, the results of a such a search using the Eight-meter-wavelength Transient Array (ETA). No compelling astrophysical signal was detected in ≈ 4 hours of data implying an observational upper limit on the rate of exploding PBHs is 4.2 × 10 −7 pc −3 yr −1 for an exploding PBH with a fireball Lorentz factor of 10 4.5 for the standard scenario of Page and Hawking. This rate limit is the strongest constraint yet set for PBH explosions with this fireball Lorentz factor. Observations (∼ 300 hours) using the Arecibo Observatory were used to set a stronger constraint on the rate of PBH explosions for a fireball Lorentz factor of 10 4.6 but the limit set by those observations for the fireball Lorentz factor considered here are less stringent by more than an order of magnitude. The limits considered here are applicable to exploding PBHs in the halo of the Galaxy. These observations also imply an upper limit of 2.0 × 10 −4 pc −3 yr −1 on the rate of PBH explosions in the context of certain extra dimension models as described by Kavic et al. This rate limit is for a fireball Lorentz factor of 10 4.3 which corresponds to an extra dimension compactification scale of 3.0 × 10 −18 m.