Establishing an analogue population for the most distant galaxies

Lyman break analogues (LBAs) are local galaxies selected to match a more distant (usually z~3) galaxy population in luminosity, UV-spectral slope and physical characteristics, and so provide an accessible laboratory for exploring their properties. However, as the Lyman break technique is extended to higher redshifts, it has become clear that the Lyman break galaxies (LBGs) at z~3 are more massive, luminous, redder, more extended and at higher metallicities than their z~5 counterparts. Thus extrapolations from the existing LBA samples (which match z=3 properties) have limited value for characterising z>5 galaxies, or inferring properties unobservable at high redshift. We present a new pilot sample of twenty-one compact star forming galaxies in the local (0.05<z<0.25) Universe, which are tuned to match the luminosities and star formation volume densities observed in z>~5 LBGs. Analysis of optical emission line indices suggests that these sources have typical metallicities of a few tenths Solar (again, consistent with the distant population). We also present radio continuum observations of a subset of this sample (13 sources) and determine that their radio fluxes are consistent with those inferred from the ultraviolet, precluding the presence of a heavily obscured AGN or significant dusty star formation.Comment: 13 pages, MNRAS accepte

Territorial Sovereignty and the Evolving Boumediene Factors: Al Maqaleh v. Gates and the Future of Detainee Habeas Corpus Rights

[Excerpt] “In November 2010, the U.S. government prosecuted in a civilian federal court an accused terrorist detainee housed since 2004 at the Guantanamo Bay Detention Center (Guantanamo Bay). The Obama Administration considered this trial a “test case” for prosecuting accused terrorist detainees in civilian federal courts. Of the more than 280 charges against the detainee defendant, a civilian jury convicted him of one count and acquitted him of the remaining charges. Yet, the defendant received a life sentence without parole. This “test case” is one example of a changing landscape in international armed conflict and detainee rights jurisprudence following September 11, 2001. This Note discusses one area of American constitutional law that has clearly evolved in recent detainee rights litigation: the extraterritorial reach of the Suspension Clause and extension of habeas corpus rights to detainees held beyond U.S. sovereign territory. Historically, territorial sovereignty determined the extraterritorial reach of the Suspension Clause. In 2008, however, Boumediene v. Bush greatly impacted the role of territorial sovereignty in extraterritorial habeas jurisprudence. In Boumediene, the Supreme Court developed a practical, multi-factor test for determining the reach of the Suspension Clause while holding that federal courts were not foreclosed from entertaining habeas petitions from Guantanamo Bay detainees. This was the first decision to allow detainee foreign nationals held beyond U.S. sovereign territory to seek habeas corpus relief through the federal courts. Now that Guantanamo Bay has been addressed, recently, the focus has shifted to detainees held at the Bagram Theater Internment Facility (Bagram) in Afghanistan. In May 2010, the D.C. Circuit in Al Maqaleh v. Gates held that the balance of Boumediene’s multi-factor test weighed against extending the Suspension Clause to four detainees captured beyond Afghanistan and detained at Bagram as unlawful enemy combatants. By analyzing the development of the Boumediene multifactor test and focusing on its application to the Bagram detainees, this Note proposes that territorial sovereignty is no longer a controlling or driving factor in today’s extraterritorial habeas analysis. Furthermore, this Note provides a few practical recommendations for future applications of the Boumediene multi-factor test and addresses some unanswered questions in applying the test in future detainee cases. Part II provides a brief history of the extraterritorial habeas jurisprudence relating to foreign national detainees leading up to Al Maqaleh. Part III discusses the Al Maqaleh decisions in both the district court and the court of appeals. Part IV analyzes the declining role that territorial sovereignty plays in today’s habeas analysis. Part IV also discusses various unanswered questions that await decision by the Supreme Court in applying the Boumediene test in future detainee cases.

Parallel density matrix propagation in spin dynamics simulations

Several methods for density matrix propagation in distributed computing environments, such as clusters and graphics processing units, are proposed and evaluated. It is demonstrated that the large communication overhead associated with each propagation step (two-sided multiplication of the density matrix by an exponential propagator and its conjugate) may be avoided and the simulation recast in a form that requires virtually no inter-thread communication. Good scaling is demonstrated on a 128-core (16 nodes, 8 cores each) cluster.Comment: Submitted for publicatio

Relative importance of crystal field versus bandwidth to the high pressure spin transition in transition metal monoxides

The crystal field splitting and d bandwidth of the 3d transition metal monoxides MnO, FeO, CoO and NiO are analyzed as a function of pressure within density functional theory. In all four cases the 3d bandwidth is significantly larger than the crystal field splitting over a wide range of compressions. The bandwidth actually increases more as pressure is increased than the crystal field splitting. Therefore the role of increasing bandwidth must be considered in any explanation of a possible spin collapse that these materials may exhibit under pressure.Comment: 7 pages, 4 figure

Radio Observations of GRB Host Galaxies

We present 5.5 and 9.0 GHz observations of a sample of seventeen GRB host galaxies at 0.5<z<1.4, using the radio continuum to explore their star formation properties in the context of the small but growing sample of galaxies with similar observations. Four sources are detected, one of those (GRB 100418A) likely due to lingering afterglow emission. We suggest that the previously-reported radio afterglow of GRB 100621A may instead be due to host galaxy flux. We see no strong evidence for redshift evolution in the typical star formation rate of GRB hosts, but note that the fraction of `dark' bursts with detections is higher than would be expected given constraints on the more typical long GRB population. We also determine the average radio-derived star formation rates of core collapse supernovae at comparable redshift, and show that these are still well below the limits obtained for GRB hosts, and show evidence for a rise in typical star formation rate with redshift in supernova hosts.Comment: 15 pages, MNRAS accepte