TeV gamma rays and cosmic rays from the nucleus of M87, a mis-aligned BL Lac object

The unresolved nuclear region of M87 emits strong non-thermal emission from radio to X-rays. Assuming this emission to originate in the pc scale jet aligned at $\theta \sim 30^\circ$ to the line of sight, we interpret this emission in the context of the Synchrotron Proton Blazar (SPB) model. We find the observed nuclear jet emission to be consistent with M87 being a mis-aligned BL Lac Object and predict gamma-ray emission extending up to at least 100 GeV at a level easily detectable by GLAST and MAGIC, and possibly by VERITAS depending on whether it is high-frequency or low-frequency peaked. Predicted neutrino emission is below the sensitivity of existing and planned neutrino telescopes. Ultra-high energy neutrons produced in pion photoproduction interactions decay into protons after escaping from the host galaxy. Because energetic protons are deflected by the intergalactic magnetic field, the protons from the decay of neutrons emitted in all directions, including along the jet axis where the Doppler factor and hence emitted neutron energies are higher, can contribute to the observed ultra-high energy cosmic rays. We consider the propagation of these cosmic ray protons to Earth and conclude that M87 could account for the observed flux if the extragalactic magnetic field topology were favourable.Comment: 17 pages, 6 figures. 3 additional references plus minor changes, acctepted for publication in Astroparticle Physic

¡Americano! Roger Clyne and the Peacemakers Rock the Borderlands of Transnational America

Cataloged from PDF version of article.In the mid 1990s, Roger Clyne was frontman for The Refreshments, well-known in the Tempe, AZ college scene and briefly famous for their radio pop single, “Banditos.” Since The Refreshments’ first indie release album in 1994, Roger Clyne and his new band, Roger Clyne & the Peacemakers,2 have become a staple on the independent music scene in Arizona and the US Southwest. While Clyne’s music lapses into happy stereotypes and romanticized depictions of the US-Mexico borderlands, his musical utopia represents an alternative cultural politics that explores (albeit clumsily) border crossings, difference, and transnationalism. Using a personal interviews with Clyne and a critical reading of his lyrics, this article explores how Clyne invokes the US-Mexico borderlands as a region with specific landscapes, musical traditions, and mythologies, and also as a metaphor for social change (by breaking down barriers). He revises traditional US-Mexico borderlands musical traditions, such as the border ballad (corrido), and asserts a transnational borderlands identity—the ¡Americano!—that exists comfortably uncomfortable between the seams (and sounds) of cultures. Clyne’s music is significant for the way it asks listeners and critics to reimagine the musical-cultural spaces of nation and identity, while advocating for compassionate alternatives to violence from a region characterized by power imbalances, inequality, and violence. Critic Josh Kun tells us that popular music gives us space to encounter ourselves—we hear ourselves in our favorite songs and come to know and build our identities through our relationships with music. The convergence of sound, space, and identity creates “audiotopias,” Kun argues, where listeners confront “the spaces that the music itself contains, the spaces that music fills up, the spaces that music helps us to imagine” (21).3 An analysis of Roger Clyne’s music and lyrics is enriched by Kun’s theory of audiotopias. As audiotopias, Clyne’s musical borderlands are a chronotope defined by border crossings that offer new ways of charting contemporar

All the Pretty Mexican Girls: Whiteness and Racial Desire in Cormac McCarthy's All the Pretty Horses and Cities of the Plain

Cataloged from PDF version of article.“All the Pretty Mexican Girls: Whiteness and Racial Desire in Cormac McCarthy’s All the Pretty Horses and Cities of the Plain” uses a critical analysis of race and gender to argue that John Grady Cole’s relationship with Alejandra and Magdalena invokes a larger and longer history of the commodification and sexualization of women’s bodies in the contact zone of the US-Mexico borderlands. The critical concerns this article addresses seek to re-situate McCarthy’s influential borderlands writing within a more nuanced series of border encounters that expose how transactions between regional, national, and international material realities on the US-Mexico border make available certain identities and modes of representation. Exposing the links between McCarthy’s representations and real-world material realities are crucial to this analysis because they reveal how McCarthy both accounts for and disavows the operations of power and history on the US-Mexico border. McCarthy’s border novels represent an in-between space where western history and the Western genre can be self-consciously invoked and revised, but only to a certain extent. John Grady Cole may be a more compassionate and “politically correct” John Wayne, yet the violence, sexual and otherwise, perpetrated on the bodies of brown women in the Border Trilogy reminds us how much McCarthy’s white masculinities rely on such abject bodies in order to fashion their own ambivalent agency in the brutal world of McCarthy’s borderlands

The Monoceros very-high-energy gamma-ray source

The H.E.S.S. telescope array has observed the complex Monoceros Loop SNR/Rosette Nebula region which contains unidentified high energy EGRET sources and potential very-high-energy (VHE) gamma-ray source. We announce the discovery of a new point-like VHE gamma-ray sources, HESS J0632+057. It is located close to the rim of the Monoceros SNR and has no clear counterpart at other wavelengths. Data from the NANTEN telescope have been used to investigate hadronic interactions with nearby molecular clouds. We found no evidence for a clear association. The VHE gamma-ray emission is possibly associated with the lower energy gamma-ray source 3EG J0634+0521, a weak X-ray source 1RXS J063258.3+054857 and the Be-star MWC 148.Comment: 4 pages, 4 figures, Contribution to the 30th ICRC, Merida Mexico, July 200

The GeV-TeV Connection in Galactic gamma-ray sources

Recent observations with atmospheric Cherenkov telescope systems such as H.E.S.S. and MAGIC have revealed a large number of new sources of very-high-energy (VHE) gamma-rays from 100 GeV - 100 TeV, mostly concentrated along the Galactic plane. At lower energies (100 MeV - 10 GeV) the satellite-based instrument EGRET revealed a population of sources clustering along the Galactic Plane. Given their adjacent energy bands a systematic correlation study between the two source catalogues seems appropriate. Here, the populations of Galactic sources in both energy domains are characterised on observational as well as on phenomenological grounds. Surprisingly few common sources are found in terms of positional coincidence and spectral consistency. These common sources and their potential counterparts and emission mechanisms will be discussed in detail. In cases of detection only in one energy band, for the first time consistent upper limits in the other energy band have been derived. The EGRET upper limits are rather unconstraining due to the sensitivity mismatch to current VHE instruments. The VHE upper limits put strong constraints on simple power-law extrapolation of several of the EGRET spectra and thus strongly suggest cutoffs in the unexplored energy range from 10 GeV - 100 GeV. Physical reasons for the existence of cutoffs and for differences in the source population at GeV and TeV energies will be discussed. Finally, predictions will be derived for common GeV - TeV sources for the upcoming GLAST mission bridging for the first time the energy gap between current GeV and TeV instruments.Comment: (1) Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), Stanford, USA (2) Stanford University, W.W. Hansen Experimental Physics Lab (HEPL) and KIPAC, Stanford, USA (3) ICREA & Institut de Ciencies de l'Espai (IEEC-CSIC) Campus UAB, Fac. de Ciencies, Barcelona, Spain. (4) School of Physics and Astronomy, University of Leeds, UK. Paper Submitted to Ap

Discussion: Reporting and calibration of post-bomb 14C data

The definitive paper by Stuiver and Polach (1977) established the conventions for reporting of radiocarbon data for chronological and geophysical studies based on the radiocactive decay of 14C in the sample since the year of sample death or formation. Several ways of reporting 14C activity levels relative to a standard were also established, but no specific instructions were given for reporting nuclear weapons-testing (post-bomb) 14C levels in samples. Because the use of post-bomb 14C is becoming more prevalent in forensice, biology, and geosciences, a convention needs to be adopted. We advocate the use of fraction modern with a new symbol F14C to prevent confusion with the previously used Fm, which may or may not have been fractionation-corrected. We also discuss the calibration of post-bomb 14c samples and the available data sets and compilations, but do not give a recommendation for a particular data set

Marine reservoir corrections : St. Helena, South Atlantic Ocean

We present the first marine reservoir age and ∆R determination for the island of St. Helena using marine mollusk radiocarbon dates obtained from an historical context of known age. This represents the first marine reservoir age and ∆R determination in the southern Atlantic Ocean within thousands of kilometers of the island. The depletion of 14C in the shells indicates a rather larger reservoir age for that portion of the surface Atlantic than models indicate. The implication is that upwelling old water along the Namibian coast is transported for a considerable distance, although it is likely to be variable on a decadal timescale. An artilleryman’s button, together with other artifacts found in a midden, demonstrate association of the mollusk shells with a narrow historic period of AD 1815–1835