Royal Institute and Observatory of the Spanish Navy

About: Royal Institute and Observatory of the Spanish Navy is a facility organization based out in San Fernando, Spain. It is known for research contribution in the topics: Gamma-ray burst & Magnetic anomaly. The organization has 50 authors who have published 106 publications receiving 2565 citations. The organization is also known as: Instituto y Observatorio de Marina de San Fernando.

Precision measurement of the neutrino velocity with the ICARUS detector in the CNGS beam

Abstract: During May 2012, the CERN-CNGS neutrino beam has been operated for two weeks for a total of ~1.8 × 1017 p.o.t., with the proton beam made of bunches, few ns wide and separated by 100 ns. This beam structure allows a very accurate time of flight measurement of neutrinos from CERN to LNGS on an event-by-event basis. Both the ICARUS-T600 PMT-DAQ and the CERN-LNGS timing synchronization have been substantially improved for this campaign, taking advantage of additional independent GPS receivers, both at CERN and LNGS as well as of the deployment of the “White Rabbit” protocol both at CERN and LNGS. The ICARUS-T600 detector has collected 25 beam-associated events; the corresponding time of flight has been accurately evaluated, using all different time synchronization paths. The measured neutrino time of flight is compatible with the arrival of all events with speed equivalent to the one of light: the difference between the expected value based on the speed of light and the measured value is δt = tof c −tof ν = 0.10 ± 0.67stat. ± 2.39syst. ns. This result is in agreement with the value previously reported by the ICARUS Collaboration, δt = 0.3 ± 4.9stat. ± 9.0syst. ns, but with improved statistical and systematic accuracy.

GRB 011121: A Collimated Outflow into Wind-blown Surroundings

Abstract: We report optical and near-infrared follow-up observations of GRB 011121 collected predominantly at ESO telescopes in Chile. We discover a break in the afterglow light curve after 1.3 days, which implies an initial jet opening angle of about 9 � . The jet origin of this break is supported by the fact that the spectral energy distribution is achromatic during the first 4 days. During later phases, GRB 011121 shows significant excess emission above the flux predicted by a power law, which we interpret as additional light from an underlying supernova. In particular, the spectral energy distribution of the optical transient approximately 2 weeks after the burst is clearly not of power-law type but can be presented by a blackbody with a temperature of � 6000 K. The deduced parameters for the decay slope and the spectral index favor a wind scenario, i.e., an outflow into a circumburst environment shaped by the stellar wind of a massive gamma-ray burst (GRB) progenitor. Because of its low redshift of z ¼ 0:36, GRB 011121 has been the best example for the GRB-supernova connection until GRB 030329 and provides compelling evidence for a circumburster wind region expected to exist if the progenitor was a massive star. Subject headings: gamma rays: bursts — supernovae: general — techniques: photometric On-line material: color figures

Frozen Orbits About the Moon

Abstract: Frozen orbits are of special interest to mission designers of artificial satellites. On average the eccentricity and argument of the perigee of such orbits remain stationary. Frozen orbits correspond to equilibria in an averaged form of the zonal problem and are almost periodic solutions of the full (nonaveraged) problem. In the zonal problem of a satellite around the moon, we numerically continue natural families of periodic orbits with the polar component of the angular momentum as the parameter. Three families of frozen orbits are discovered.

Search for transient variations of the fine structure constant and dark matter using fiber-linked optical atomic clocks

Abstract: We search for transient variations of the fine structure constant using data from a European network of fiber-linked optical atomic clocks. By searching for coherent variations in the recorded clock frequency comparisons across the network, we significantly improve the constraints on transient variations of the fine structure constant. For example, we constrain the variation to |δα/α| ~10^4 km) objects.

Piecewise delamination of Moroccan lithosphere from beneath the Atlas Mountains

Abstract: The elevation of the intracontinental Atlas Mountains of Morocco and surrounding regions requires a mantle component of buoyancy, and there is consensus that this buoyancy results from an abnormally thin lithosphere. Lithospheric delamination under the Atlas Mountains and thermal erosion caused by upwelling mantle have each been suggested as thinning mechanisms. We use seismic tomography to image the upper mantle of Morocco. Our imaging resolves the location and shape of lithospheric cavities and of delaminated lithosphere ∼400 km beneath the Middle Atlas. We propose discontinuous delamination of an intrinsically unstable Atlas lithosphere, enabled by the presence of anomalously hot mantle, as a mechanism for producing the imaged structures. The Atlas lithosphere was made unstable by a combination of tectonic shortening and eclogite loading during Mesozoic rifting and Cenozoic magmatism. The presence of hot mantle sourced from regional upwellings in northern Africa or the Canary Islands enhanced the instability of this lithosphere. Flow around the retreating Alboran slab focused upwelling mantle under the Middle Atlas, which we infer to be the site of the most recent delamination. The Atlas Mountains of Morocco stand as an example of large-scale lithospheric loss in a mildly contractional orogen.