|
Records |
Links |
|
Author |
Magalhaes, R.B.; Ribeiro, G.P.; Lima, H.C.D.J.; Olmo, G.J.; Crispino, L.C.B. |
![goto web page (via DOI) doi](img/doi.gif)
|
|
Title |
Singular space-times with bounded algebraic curvature scalars |
Type |
Journal Article |
|
Year |
2024 |
Publication ![sorted by Publication field, descending order (down)](img/sort_desc.gif) |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
|
|
Volume |
05 |
Issue |
5 |
Pages |
114 - 34pp |
|
|
Keywords |
gravity; modified gravity; Wormholes |
|
|
Abstract |
We show that the absence of unbounded algebraic curvature invariants constructed from polynomials of the Riemann tensor cannot guarantee the absence of strong singularities. As a consequence, it is not sufficient to rely solely on the analysis of such scalars to assess the regularity of a given space-time. This conclusion follows from the analysis of incomplete geodesics within the internal region of asymmetric wormholes supported by scalar matter which arise in two distinct metric-affine gravity theories. These wormholes have bounded algebraic curvature scalars everywhere, which highlights that their finiteness does not prevent the emergence of pathologies (singularities) in the geodesic structure of space-time. By analyzing the tidal forces in the internal wormhole region, we find that the angular components are unbounded along incomplete radial time-like geodesics. The strength of the singularity is determined by the evolution of Jacobi fields along such geodesics, finding that it is of strong type, as volume elements are torn apart as the singularity is approached. Lastly, and for completeness, we consider the wormhole of the quadratic Palatini theory and present an analysis of the tidal forces in the entire space-time. |
|
|
Address |
[Magalhaes, Renan B.; Ribeiro, Gabriel P.; Lima Jr, Haroldo C. D.; Crispino, Luis C. B.] Univ Fed Para, Programa Posgrad Fis, BR-66075110 Belem, Para, Brazil, Email: renan.magalhaes@icen.ufpa.br; |
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
IOP Publishing Ltd |
Place of Publication |
|
Editor |
|
|
|
Language |
English |
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
1475-7516 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
WOS:001265908300012 |
Approved |
no |
|
|
Is ISI |
yes |
International Collaboration |
yes |
|
|
Call Number |
IFIC @ pastor @ |
Serial |
6200 |
|
Permanent link to this record |
|
|
|
|
Author |
Pierre Auger Collaboration (Abreu, P. et al); Pastor, S. |
![goto web page (via DOI) doi](img/doi.gif)
|
|
Title |
Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter |
Type |
Journal Article |
|
Year |
2010 |
Publication ![sorted by Publication field, descending order (down)](img/sort_desc.gif) |
Astroparticle Physics |
Abbreviated Journal |
Astropart Phys. |
|
|
Volume |
34 |
Issue |
5 |
Pages |
314-326 |
|
|
Keywords |
Cosmic rays; UHECR; Anisotropy; Pierre Auger Observatory; Extra-galactic; GZK |
|
|
Abstract |
Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuz'min energy threshold, 6 x 10(19) eV. The anisotropy was measured by the fraction of arrival directions that are less than 3.1 degrees from the position of an active galactic nucleus within 75 Mpc (using the Veron-Cetty and Veron 12th catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is (38(-6)(+7))%, compared with 21% expected for isotropic cosmic rays. This is down from the early estimate of (69-(+11)(13))%. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation. |
|
|
Address |
[Allekotte, I.; Asorey, H.; Bertou, X.; Golup, G.; Gomez Berisso, M.; Harari, D.; Mollerach, S.; Ponce, V. H.; Roulet, E.] Ctr Atom Bariloche, San Carlos De Bariloche, Rio Negro, Argentina |
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
Elsevier Science Bv |
Place of Publication |
|
Editor |
|
|
|
Language |
English |
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0927-6505 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
ISI:000284669100007 |
Approved |
no |
|
|
Is ISI |
yes |
International Collaboration |
yes |
|
|
Call Number |
IFIC @ elepoucu @ |
Serial |
320 |
|
Permanent link to this record |
|
|
|
|
Author |
ANTARES Collaboration (Aguilar, J.A. et al); Bigongiari, C.; Dornic, D.; Emanuele, U.; Gomez-Gonzalez, J.P.; Hernandez-Rey, J.J.; Mangano, S.; Salesa, F.; Toscano, S.; Yepes, H.; Zornoza, J.D.; Zuñiga, J. |
![goto web page (via DOI) doi](img/doi.gif)
|
|
Title |
Zenith distribution and flux of atmospheric muons measured with the 5-line ANTARES detector |
Type |
Journal Article |
|
Year |
2010 |
Publication ![sorted by Publication field, descending order (down)](img/sort_desc.gif) |
Astroparticle Physics |
Abbreviated Journal |
Astropart Phys. |
|
|
Volume |
34 |
Issue |
3 |
Pages |
179-184 |
|
|
Keywords |
Atmospheric muons; Neutrino telescope; Depth-intensity relation |
|
|
Abstract |
The ANTARES high-energy neutrino telescope is a three-dimensional array of about 900 photomultipliers distributed over 12 mooring lines installed in the Mediterranean Sea. Between February and November 2007 it acquired data in a 5-line configuration. The zenith angular distribution of the atmospheric muon flux and the associated depth-intensity relation are measured and compared with previous measurements and Monte Carlo expectations. An evaluation of the systematic effects due to uncertainties on environmental and detector parameters is presented. |
|
|
Address |
[Bazzotti, M.; Biagi, S.; Carminati, G.; Giacomelli, G.; Margiotta, A.; Spurio, M.] Dipartimento Fis Univ, I-40127 Bologna, Italy, Email: Annarita.Margiotta@bo.infn.it |
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
Elsevier Science Bv |
Place of Publication |
|
Editor |
|
|
|
Language |
English |
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0927-6505 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
ISI:000282496000005 |
Approved |
no |
|
|
Is ISI |
yes |
International Collaboration |
yes |
|
|
Call Number |
IFIC @ elepoucu @ |
Serial |
373 |
|
Permanent link to this record |
|
|
|
|
Author |
ANTARES Collaboration (Aguilar, J.A. et al); Bigongiari, C.; Dornic, D.; Emanuele, U.; Gomez-Gonzalez, J.P.; Hernandez-Rey, J.J.; Mangano, S.; Salesa, F.; Toscano, S.; Yepes, H.; Zornoza, J.D.; Zuñiga, J. |
![goto web page (via DOI) doi](img/doi.gif)
|
|
Title |
A fast algorithm for muon track reconstruction and its application to the ANTARES neutrino telescope |
Type |
Journal Article |
|
Year |
2011 |
Publication ![sorted by Publication field, descending order (down)](img/sort_desc.gif) |
Astroparticle Physics |
Abbreviated Journal |
Astropart Phys. |
|
|
Volume |
34 |
Issue |
9 |
Pages |
652-662 |
|
|
Keywords |
Neutrino telescope; Track reconstruction |
|
|
Abstract |
An algorithm is presented, that provides a fast and robust reconstruction of neutrino induced upward-going muons and a discrimination of these events from downward-going atmospheric muon background in data collected by the ANTARES neutrino telescope. The algorithm consists of a hit merging and hit selection procedure followed by fitting steps for a track hypothesis and a point-like light source. It is particularly well-suited for real time applications such as online monitoring and fast triggering of optical follow-up observations for multi-messenger studies. The performance of the algorithm is evaluated with Monte Carlo simulations and various distributions are compared with that obtained in ANTARES data. |
|
|
Address |
[Carminati, G.] Leiden Univ, NL-2300 RA Leiden, Netherlands, Email: brunner@ifh.de |
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
Elsevier Science Bv |
Place of Publication |
|
Editor |
|
|
|
Language |
English |
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0927-6505 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
ISI:000289329100002 |
Approved |
no |
|
|
Is ISI |
yes |
International Collaboration |
yes |
|
|
Call Number |
IFIC @ pastor @ |
Serial |
608 |
|
Permanent link to this record |
|
|
|
|
Author |
Pierre Auger Collaboration (Abreu, P. et al); Pastor, S. |
![goto web page (via DOI) doi](img/doi.gif)
|
|
Title |
The exposure of the hybrid detector of the Pierre Auger Observatory |
Type |
Journal Article |
|
Year |
2011 |
Publication ![sorted by Publication field, descending order (down)](img/sort_desc.gif) |
Astroparticle Physics |
Abbreviated Journal |
Astropart Phys. |
|
|
Volume |
34 |
Issue |
6 |
Pages |
368-381 |
|
|
Keywords |
Ultra high energy cosmic rays; Pierre Auger Observatory; Extensive air showers; Trigger; Exposure; Fluorescence detector; Hybrid |
|
|
Abstract |
The Pierre Auger Observatory is a detector for ultra-high energy cosmic rays. It consists of a surface array to measure secondary particles at ground level and a fluorescence detector to measure the development of air showers in the atmosphere above the array. The “hybrid” detection mode combines the information from the two subsystems. We describe the determination of the hybrid exposure for events observed by the fluorescence telescopes in coincidence with at least one water-Cherenkov detector of the surface array. A detailed knowledge of the time dependence of the detection operations is crucial for an accurate evaluation of the exposure. We discuss the relevance of monitoring data collected during operations, such as the status of the fluorescence detector, background light and atmospheric conditions, that are used in both simulation and reconstruction. |
|
|
Address |
[Ave, M.; Bluemer, H.; Daumiller, K.; Dembinski, H.; Engel, R.; Garrido, X.; Haungs, A.; Heck, D.; Huege, T.; Keilhauer, B.; Klages, H. O.; Kleinfeller, J.; Mathes, H. J.; Mueller, S.; Oehlschlaeger, J.; Pierog, T.; Roth, M.; Salamida, F.; Schieler, H.; Schroeder, F.; Schuessler, F.; Smida, R.; Ulrich, R.; Unger, M.; Valino, I.; Weinidl, A.; Will, M.; Wommer, M.] Karlsruhe Inst Technol, Inst Kernphys, Karlsruhe, Germany, Email: francesco.salamida@kit.edu |
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
Elsevier Science Bv |
Place of Publication |
|
Editor |
|
|
|
Language |
English |
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0927-6505 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
ISI:000287068800007 |
Approved |
no |
|
|
Is ISI |
yes |
International Collaboration |
yes |
|
|
Call Number |
IFIC @ pastor @ |
Serial |
580 |
|
Permanent link to this record |