Voices of Change from Great Britain

SPEA Lecturer Bill Foley highlights students' experiences while studying national security in London during Brexit

Tough Decisions: Defending the Homeland

Produced by WFYI, in partnership with the Indiana University School of Law - Indianapolis and the IU School of Public and Environmental Affairs. Tough Decisions: Defending the Homeland takes viewers behind-the-scenes at a groundbreaking simulation of terrorism event. The exercise forces a new generation of global leaders to develop innovative counter-terrorism tactics and strategies in order to disrupt terrorist activities, while restoring public safety and maintaining First Amendment rights. Viewable at https://iu.mediaspace.kaltura.com/media/Tough+Decision.mp4/1_slb6dra

A Neutron Star Binary Merger Model for GW170817/GRB170817a/SSS17a

The merging neutron star gravitational wave event GW170817 has been observed throughout the entire electromagnetic spectrum from radio waves to $\gamma$-rays. The resulting energetics, variability, and light curves are shown to be consistent with GW170817 originating from the merger of two neutron stars, in all likelihood followed by the prompt gravitational collapse of the massive remnant. The available $\gamma$-ray, X-ray and radio data provide a clear probe for the nature of the relativistic ejecta and the non-thermal processes occurring within, while the ultraviolet, optical and infrared emission are shown to probe material torn during the merger and subsequently heated by the decay of freshly synthesized $r$-process material. The simplest hypothesis that the non-thermal emission is due to a low-luminosity short $\gamma$-ray burst (sGRB) seems to agree with the present data. While low luminosity sGRBs might be common, we show here that the collective prompt and multi-wavelength observations are also consistent with a typical, powerful sGRB seen off-axis. Detailed follow-up observations are thus essential before we can place stringent constraints on the nature of the relativistic ejecta in GW170817.Comment: 9 pages, 5 figures, accepted to ApJ Letter

Measuring the Effect of USCG Port Security Advisory Notices On Trade and Port Security Procedures

Overview: The United States Coast Guard’s International Port Security (IPS) Program is the primary port security assessment office and was established in 2003 as part of the U.S. Maritime Transportation Security Act (MTSA) to reduce risks to U.S. ports and ships, and to the entire maritime transport system. Through the assessment of International Ship and Port Facility Security Code implementation and other measures in foreign ports, the International Port Security Program can determine whether or not there is a reasonable and acceptable level of port security at any given foreign port. This report is comprised of qualitative and quantitative research along with two case studies that compare and contrast two countries and/or ports that either succeeded or failed in complying with this program and received a Port Security Advisory (PSA). Hypothesis: Port Security Advisories (PSA) are issued when a port does not meet the International Port Security Program code. They are an instrument to build and sustain port security practices and improvements. PSAs can give standard regulations for those who use ports in compliance with a PSA as well as create maritime security protocols for other countries that do not have strong port standards. As for the economic impacts, there can be both positive and negative factors depending on the country and the situation. However, we hypothesize that overall, PSAs do not significantly influence a country’s volume of trade. Due to non-compliant countries in reporting, there is no discernable method for tracking or ensuring restrictions. Methodology: We will observe quantitative measures of trade to identify negative impacts associated with the issuance of PSAs. We will also look at quantitative data to identify positive impacts associated with PSAs. We will be using USCG’s HOMEPORT website to identify the PSAs and use COMTRADE to examine trade both before and after a PSA was issued. Trade will be compared to similar countries, those which have not received a PSA. Lastly, we will go over local and regional factors and determine what is currently working and what needs to be improved. Conclusions: Our conclusion is that as a system the PSA process is not necessary an influence on trade. There may be correlations between countries with PSAs issued and changes in trade but there are a myriad of other factors that can impact this making the current methodology less than definitive. There also may be certain countries and/or ports where the correlation appears stronger (See Case Study #1); but overall, our conclusion is that PSAs have a negligible impact on a country receiving them in influencing their volume of trade

The Fermi GBM Gamma-Ray Burst Spectral Catalog: Four Years Of Data

In this catalog we present the updated set of spectral analyses of GRBs detected by the Fermi Gamma-Ray Burst Monitor (GBM) during its first four years of operation. It contains two types of spectra, time-integrated spectral fits and spectral fits at the brightest time bin, from 943 triggered GRBs. Four different spectral models were fitted to the data, resulting in a compendium of more than 7500 spectra. The analysis was performed similarly, but not identically to Goldstein et al. 2012. All 487 GRBs from the first two years have been re-fitted using the same methodology as that of the 456 GRBs in years three and four. We describe, in detail, our procedure and criteria for the analysis, and present the results in the form of parameter distributions both for the observer-frame and rest-frame quantities. The data files containing the complete results are available from the High-Energy Astrophysics Science Archive Research Center (HEASARC).Comment: Accepted for publication in ApJ

The 2nd Fermi GBM Gamma-Ray Burst Catalog: The First Four Years

This is the second of a series of catalogs of gamma-ray bursts (GRBs) observed with the Fermi Gamma-ray Burst Monitor (GBM). It extends the first two-year catalog by two more years, resulting in an overall list of 953 GBM triggered GRBs. The intention of the GBM GRB catalog is to provide information to the community on the most important observables of the GBM detected GRBs. For each GRB the location and main characteristics of the prompt emission, the duration, peak flux and fluence are derived. The latter two quantities are calculated for the 50 - 300 keV energy band, where the maximum energy release of GRBs in the instrument reference system is observed and also for a broader energy band from 10 - 1000 keV, exploiting the full energy range of GBMs low-energy detectors. Furthermore, information is given on the settings and modifications of the triggering criteria and exceptional operational conditions during years three and four in the mission. This second catalog is an official product of the Fermi GBM science team, and the data files containing the complete results are available from the High-Energy Astrophysics Science Archive Research Center (HEASARC).Comment: 151 pages, 10 figures, 9 tables; to be published in ApJ

Temporal Deconvolution study of Long and Short Gamma-Ray Burst Light curves

The light curves of Gamma-Ray Bursts (GRBs) are believed to result from internal shocks reflecting the activity of the GRB central engine. Their temporal deconvolution can reveal potential differences in the properties of the central engines in the two populations of GRBs which are believed to originate from the deaths of massive stars (long) and from mergers of compact objects (short). We present here the results of the temporal analysis of 42 GRBs detected with the Gamma-ray Burst Monitor onboard the Fermi Gamma-ray Space Telescope. We deconvolved the profiles into pulses, which we fit with lognormal functions. The distributions of the pulse shape parameters and intervals between neighboring pulses are distinct for both burst types and also fit with lognormal functions. We have studied the evolution of these parameters in different energy bands and found that they differ between long and short bursts. We discuss the implications of the differences in the temporal properties of long and short bursts within the framework of the internal shock model for GRB prompt emission.Comment: 38 pages, 11 figure