High energy galactic gamma radiation from cosmic rays concentrated in spiral arms

A model for the emission of high energy ( 100 MeV) gamma rays from the galactic disk was developed and compared to recent SAS-2 observations. In the calculation, it is assumed that (1) the high energy galactic gamma rays result primarily from the interaction of cosmic rays with galactic matter; (2) on the basis of theoretical and experimental arguments the cosmic ray density is proportional to the matter density on the scale of galactic arms; and (3) the matter in the galaxy, atomic and molecular, is distributed in a spiral pattern consistent with density wave theory and the experimental data on the matter distribution

SAS-2 observations of the high energy gamma radiation from the Vela region

Data from a scan of the galactic plane by the SAS-B high energy gamma ray experiment in the region 250 deg smaller than 12 smaller than 290 deg show a statistically significant excess over the general radiation from the galactic plane for gamma radiation of energy larger than 100 MeV. If the enhanced gamma radiation results from interactions of cosmic rays with galactic matter, as the energy spectrum suggests, it seems reasonable to associate the enhancement with large scale galactic features, such as spiral arm segments in that direction, or with the region surrounding the Vela supernova remnant with which PSR 0833-45 is associated. If the excess is attributed to cosmic rays released from the supernova interacting with the interstellar matter in that region, than on the order of 3 x 10 to the 50th power ergs would have been released by that supernova in the form of cosmic rays

SAS-2 observations of the galactic gamma radiation from the Vela region

Data from a scan of the galactic plane by the SAS-2 high energy gamma ray experiment in the region 250 deg l2 290 deg show a statistically-significant excess over the general radiation from the galactic plane for gamma radiation of energy 100 MeV in the region 260 deg l2 270 deg and -7.5 deg b2 0 deg. If the enhanced gamma radiation results from interactions of cosmic rays with galactic matter, as the energy spectrum suggests, it seems reasonable to associate the enhancement with large scale galactic features, such as spiral arm segments in that direction, or with the region surrounding the Vela supernova remnant, with which PSR 0833-45 is associated. If the excess is attributed to cosmic rays released from this supernova interacting with the interstellar matter in that region, then on the order of 3.10 to the 50th power ergs would be released by that supernova in the form of cosmic rays

Methodologies of Exchange: MoMA's "Twentieth-Century Italian Art" (1949)

The third issue of \u201cItalian Modern Art\u201d journal by CIMA (Center for Italian Modern Art) is dedicated to MoMA 1949 exhibition Twentieth-Century Italian Art. The publication is based on the conference, \u201cMethodologies of Exchange: The Exhibition Twentieth-Century Italian Art (MoMA, 1949)\u201d organized by Raffaele Bedarida, Silvia Bignami and Davide Colombo at CIMA in New York in February 2019, in connection with the Annual Conference of the College Art Association and the 70th anniversary of the original exhibition. The conference was made possible by a Terra Foundation for American Art grant. The exhibition Twentieth-Century Italian Art at the Museum of Modern Art in New York, which constructed dominant interpretive keys that today continue to affect the study and perception of Italian modernism. In effect Twentieth-Century Italian Art was the first opportunity after World War II for American audiences to see the work of a substantial group of contemporary Italian artists. Curated by James Thrall Soby and Alfred H. Barr, Jr., the exhibition was followed by a vast campaign of acquisitions: MoMA added key Italian artists, from Umberto Boccioni to Lucio Fontana, to its permanent collection and thereby situated them within the museum\u2019s influential narrative of modernism. Further, the Italian show aided MoMA curators in revising their institutional perspective in the Cold War context, moving it beyond a Paris-centered canon. By studying this exhibition from multiple angles, this issue intends to explore and combine various methodological approaches. The initiative involved a group of international scholars who have focused on topics connected with Twentieth-Century Italian Art and the Italy-U.S. relationship from different fields of study, including exhibition histories, cultural transfer, cultural diplomacy, art and politics, the history of collecting, the history of the art market, and more

Gamma radiation from the Crab nebula above 35 MeV

Electromagnetic radiation from the Crab nebula were observed, showing that the Crab is unique among strong X-ray sources in that major component in the low energy range (1 to 10 KeV) shows little or no temporal variation. Observations of the Crab above 35 MeV were made with the high energy gamma ray telescope flown on SAS-2. The detector and technique are described in detail

Natural risk management for industrial plants and infrastructures: the DaBo system

Natural risk management on complex critical infrastructures often requires integration of data coming out from a huge number of sensors. Solutions are sometimes derived by classical supervisory control and data acquisition systems (SCADAs), usually employed in manufacturing and industrial plants environment. This “control room” approach often proves to be ineffective when the system to be monitored goes beyond the limits of the single plant and it is extended to the surrounding environment including buildings and public infrastructures in a strong interaction with local communities. The paper presents the case study of a hydroelectric plant extended over a territory of a few tens of square kilometers and subject to hydrogeological problems of various kinds, with interactions with buildings and infrastructures. The huge number of sensors installed for production control proved to be far to monitor the safety of the plant in its environmental context. We present here the risk assessment procedure and the proposed actions, also in terms of sensor installation. DaBo platform work as a data integrator. The structural and hydraulic “ordinary state” is continuously generated by means of numerical modeling basing upon real time observed boundary conditions. This state, via a suitable set of state variables, is compared with sensor data allowing a clear synthesis of the safety of the infrastructure and its natural and anthropic context. DaBo poses itself as a systems integrator both from a conceptual and an operational point of view, able to activate direct measures to reduce the risk in case of emergency, involving also local civil protection authorities. The platform integrates information from a wide range of sensors (viz. temperature, water level, strain, water content), weather alerts, weather forecast from high resolution limited area models. The main innovation of DaBo consists in the dashboard designed to provide communication of risk to the end user and to link the warnings to action procedures. It is technically a responsive single page web application that is based on an information storage and management layer by a high capacity relational database, a powerful scalable business logic tier for decision support and early warning system, and a multi profiled responsive user interface. The goal is to ensure the operation of the entire supply chain that connects the various sources of information to the entire user range

High energy gamma ray results from the second small astronomy satellite

A high energy (35 MeV) gamma ray telescope employing a thirty-two level magnetic core spark chamber system was flown on SAS 2. The high energy galactic gamma radiation is observed to dominate over the general diffuse radiation along the entire galactic plane, and when examined in detail, the longitudinal and latitudinal distribution seem generally correlated with galactic structural features, particularly with arm segments. The general high energy gamma radiation from the galactic plane, explained on the basis of its angular distribution and magnitude, probably results primarily from cosmic ray interactions with interstellar matter

Discovery of a Hard X-Ray Source, SAX J0635+0533, in the Error Box of the Gamma-Ray Source 2EG 0635+0521

We have discovered an x-ray source, SAX J0635+0533, with a hard spectrum within the error box of the GeV gamma-ray source in Monoceros, 2EG J0635+0521. The unabsorbed x-ray flux is 1.2*10^-11 erg cm^-2 s^-1 in the 2-10 keV band. The x-ray spectrum is consistent with a simple powerlaw model with absorption. The photon index is 1.50 +/- 0.08 and we detect emission out to 40 keV. Optical observations identify a counterpart with a V-magnitude of 12.8. The counterpart has broad emission lines and the colors of an early B type star. If the identification of the x-ray/optical source with the gamma-ray source is correct, then the source would be a gamma-ray emitting x-ray binary.Comment: Accepted to the Astrophysical Journal, 8 page

A time-variable, phase-dependent emission line in the X-ray spectrum of the isolated neutron star RXJ0822–4300

RX J0822−4300 is the central compact object associated with the Puppis A supernova remnant. Previous X-ray observations suggested RX J0822−4300 to be a young neutron star with a weak dipole field and a peculiar surface temperature distribution dominated by two antipodal spots with different temperatures and sizes. An emission line at 0.8 keV was also detected. We performed a very deep (130-ks) observation with XMM–Newton, which allowed us to study in detail the phase-resolved properties of RX J0822−4300. Our new data confirm the existence of a narrow spectral feature, best modelled as an emission line, only seen in the ‘soft’-phase interval – when the cooler region is best aligned to the line of sight. Surprisingly, comparison of our recent observations to the older ones yields evidence for a variation in the emission-line component, which can be modelled as a decrease in the central energy from ∼0.80 keV in 2001 to ∼0.73 keV in 2009–10. The line could be generated via cyclotron scattering of thermal photons in an optically-thin layer of gas, or, alternatively, it could originate in low-rate accretion by a debris disc. In any case, a variation in energy, pointing to a variation of the magnetic field in the line-emitting region, cannot be easily accounted for