130,794 research outputs found
Inverse Compton Scattering, Galactic Jets, GRBs and the Rings of SN1987A
No full textPrecessing neutron star jets (NSJ) in binary systems with solar-like companion are the sources of preceeding gamma jets by Inverse Compton Scattering (ICS); their sudden blazing in space is the source of GRBs. They are located in extended or giant galactic halos. Evidences of SGRs superluminal jets and the twin tenuous Rings of SN1987A are probing the existence of such (NSJ) systems
Is the stable tau-neutrino really an allowable cold dark matter candidate?
No full textConsidering the annihilation of massive tau-neutrinos in the Galactic Halo, we show that it is difficult to obtain concordance between the observed (directly on indirectly) and predicted fluxes of cosmic electrons and positrons in the case of a stable tau-neutrino with mass approximate to 1-24 MeV and magnetic moment mu similar to 10(-6) mu(B). These results exclude the possibility Tor such a tau-neutrino being the dominant cold dark matter particle component
A 20 GeVs transparent neutrino astronomy from the North Pole?
No full textMuon neutrino astronomy is drown within a polluted atmospheric neutrino noise: indeed recent ICECUBE neutrino records at (TeVs), couldn't find any muon neutrino point source [1] being blurred by such a noisy sky. However at 24 GeV energy atmospheric muon neutrinos, while rising vertically along the terrestrial diameter, should disappear (or be severely depleted) while converting into tau flavor: any rarest vertical E-mu similar or equal to 12 GeV muon track at South Pole Deep Core volume, pointing back to North Pole, might be tracing mostly a noise-free astrophysical signal. The corresponding Deep Core 6 - 7 - 8 - 9 channels trigger maybe point in those directions and inside that energy range without much background. Analogous nu(mu) suppression do not occur so efficiently elsewhere (as SuperKamiokande) because of a much smaller volume, an un-ability to test the muon birth place, its length, its expected energy. Also the smearing of the terrestrial rotation makes Deep Core ideal: along the South-North Pole the solid angle is almost steady, the flavor nu(mu) nu(tau) conversion persist while the Earth is spinning around the stable poles-axis. Therefore Deep Core detector at South Pole, may scan at E-nu mu similar or equal to 18-27 GeV energy windows, into a narrow vertical cone Delta theta similar or equal to 30 degrees for a novel nu(mu), (nu) over bar (mu) astronomy almost noise-free, pointing back toward the North Pole. Unfortunately muon (at E, 12 GeV) trace their arrival direction mostly spread around an unique string in a zenith-cone solid angle. To achieve also an azimuth angular resolution a two string detection at once is needed. Therefore the doubling of the Deep Core string number, (two new arrays of six string each, achieving an average detection distance of 36.5 m), is desirable, leading to a larger Deep Core detection mass (more than double) and a sharper zenith and azimuth angular resolution by two-string vertical axis detection. Such an improvement may show a noise free (at least factor ten) muon neutrino astronomy. This enhancement may also be a crucial probe of a peculiar anisotropy foreseen for atmospheric anti-muon, in CPT violated physics versus conserved one, following a hint by recent Minos results
Deep Core muon neutrino rate and anisotropy by mixing and CPT violation.
No full textNeutrinos are allowed to mix and to oscillate among their flavor. Muon and tau in particular oscillate at largest values.Last Minos experiment claimed possible difference among their matter and anti-matter masses, leading to a first violation of the most believed CPT symmetry.Isotropically born atmospheric muon neutrino at 20-80 GeV, while up-going, they might be partially suppressed by mixing in analogy to historical SuperKamiokande muon neutrino disappearance into tau, leading to large scale anisotropy signals. Here we show an independent muon rate foreseen in Deep Core based on observed SK signals extrapolated to DeepCore mass and its surrounding. Our rate prediction partially differ from previous ones. The neutrino muon disappearance into tau is leading to an anisotropy in vertical up-going muon track: in particular along channel 3-5 we expect a huge rate (tens of thousand of events) of neutral current events, charged current electron and inclined crossing muons. Moreover at channel 6-9 we expect a severe suppression of the rate due to muon disappearance (in CPT conserved frame). Such an anisotropy might be partially tested by more than one string detection at E> 45 GeV energy. A CPT violation may induce a more remarkable suppression of vertical up-going tracks because of larger anti-neutrino muon reduction for E> 35 GeV
Beaming Selection and SN-GRB-Jets Evolution
No full textAfter a decade of Fireball reign there is a hope for thin collimated Jet to solve the Supernova-GRB myster
An apparent GRBs evolution around us or a sampling of thin GRB beaming jets?
No full textThe gamma ray burst apparent average isotropic power versus their red-shift of all known GRB (Sept.2009) is reported. It calls for an unrealistic Gamma Ray Burst Evolution around us or it just probe the need of a very thin gamma precession-jet model. These precessing and spinning jet are originated by Inverse Compton and-or Synchrotron Radiation at pulsars or micro-quasars sources, by ultra-relativistic electrons. These Jets are most powerful at Supernova birth, blazing, once on axis, to us and flashing GRB detector. The trembling of the thin jet (spinning, precessing, bent by magnetic fields) explains naturally the observed erratic multi-explosive structure of different GRBs and its rare re-brightening. The jets are precessing (by binary companion or inner disk asymmetry) and decaying by power law on time scales to a few hours. GRB blazing occurs inside the observer cone of view only a seconds duration times; because relativistic synchrotron (or IC) laws the jet angle is thinner in gamma but wider in X band. Its apparent brightening is so well correlated with its hardness (The Amati correlation). This explain the wider and longer X GRB afterglow duration and the (not so much) rare presence of X-ray precursors well before the apparent main GRB explosion. The jet lepton maybe originated by an inner primary hadron core (as well as pions and muons secondary Jets). The EGRET, AGILE and Fermi few hardest and late GeV gamma might be PeV neutron beta decay in flight observed in-axis under a relativistic shrinkag
Could GRB170817A be really correlated to an NSâNS merging?
No full textThe exciting development of gravitational wave (GW) astronomy in the correlation of LIGO and VIRGO detection of GW signals makes possible to expect registration of effects of not only binary black hole (BH) coalescence but also binary neutron star (NS) merging accompanied by electromagnetic (gamma ray burst; GRB) signal. Here we consider the possibility that an NS, merging in an NS–NS or NS–BH system might be (soon) observed in correlation with any LIGO–VIRGO GWs detection. We analyze as an example the recent case of the short GRB170817A observed by Fermi and integral. The associated optical transient (OT) source in NGC4993 implies a rare near source, a consequent averaged large rate of such events (almost) compatible with expected NS–NS merging rate. However the expected beamed GRB (or short GRB) may be mostly aligned to a different direction than ours. Therefore, even soft GRB photons, spread more than hard ones, might be hardly able to shower to us. Nevertheless, a prompt spiraling electron turbine jet in largest magnetic fields, at the base of the NS–NS collapse, might shine by its tangential synchrotron radiation in spread way with its skimming photons shining in large open disk. The consequent solid angle for such soft disk gamma radiation may be large enough to be nevertheless often observed
Air-shower spectroscopy at horizons
No full textDownward cosmic rays are mostly revealed on the ground by their air-showers diluted and filtered secondary mu(+)mu(-) traces and/or by their (Cerenkov-Fluorescent) light because of the high altitude numerous and luminous electromagnetic e(+)e(-), gamma shower component. Horizontal and upward air-showers are even more suppressed by deeper atmosphere opacity and by the Earth shadows. In such noise-free horizontal and upward directions rare Ultra High Cosmic rays and rarer neutrino induced air-showers may shine, mostly mediated by resonant PeV v(e)(-) + e(-) -> W- interactions in air or by higher energy tau air-showers originated by v(tau) skimming the Earth. At high altitude (mountains, planes, balloons) the air density is so rarefied that nearly all common air-showers might be observed at their maximal growth at a tuned altitude and direction. The arrival angle samples different distances and the corresponding most probable primary cosmic ray energy. The larger and larger distances (between observer and C.R. interaction) make wider and wider the shower area and it enlarges the probability of being observed (up to three orders of magnitude more than vertical showers); the observation of a maximal electromagnetic shower development may amplify the signal by two-three orders of magnitude (with respect to a suppressed shower at sea level); the peculiar altitude-angle range (ten-twenty km height and similar or equal to 80 degrees-90 degrees zenith angle) may disentangle at best the primary cosmic ray energy and composition. Even from existing mountain observatories the up-going air-showers may trace, above the horizons, PeV-EeV high energy cosmic rays and, below the horizons, PeV-EeV neutrino astronomy: their early signals may be captured in already existing gamma telescopes such as Magic at Canarie, while facing the Earth edges during (useless) cloudy nights. (c) 2005 Elsevier B.V All rights reserved
Discovering Ultra High Energy Neutrinos by Horizontal and Upward tau Air-Showers: Evidences in Terrestrial Gamma Flashes ?
No full textUltra high energy neutrinos UHE neutrino Tau, anti-neutrino Tau, anti-neutrino electron at PeVs, and higher energy may induce tau air-showers whose detectability is million to billion times amplified by their secondaries. We considered UHE nu_{tau}- N and UHE bar\nu_{e}- e interactions beyond mountains as a source of such horizontal amplified Tau air-showers. We also consider vertical upward UHE nu_{tau}-N interaction on Earth crust leading to UHE Tau airshowers {UPTAUS} or at the horizont edges {HORTAUS} and their beaming toward high mountains gamma, X, Cherenkov detectors on mountains. We show their detectability. We notice that such rare upward Tau air-shower, UPTAUS and HORTAUS, may hit even nearby airlines, ballons, satellite and flash them by short diluted gamma-burst at the edge of Gamma Ray Observatory (GRO) detection threshold. We suggest the identification of these events with recent discovered (BATSE) Terrestrial Gamma Flashes and we claim their probable UHE Tau by UHE nu_\tau origin. From these data approximated UHE nu_tau flux and Delta m_{nu_mu \nu_tau} lower bound are derived. Known X-gamma-{TeV} active galactic and extragalactic sources have been identified in most TGF arrival directions. Maximal EGRET activity in galactic Center overlap with maximal TGF flux. The UHECR AGASA an-isotropy at 10^{18} eV shows also possible correlations with TGF events. The unique UHECR triplet in AGASA clustering, pointing toward BL Lac 1ES0806+524, finds, within its error box, a corresponding TGF event, BATSE (Trigger 2444). Finally a partial TGF Galactic signature, combined with above correlations suggests an astrophysical tau origin of TGF events
BOUNDS ON VERY HEAVY RELIC NEUTRINOS BY THEIR ANNIHILATION IN THE GALACTIC HALO
No full textTaking into account neutrino condensation in the gravitational field of collapsing matter, we investigate the annihilation of heavy relic neutrinos in the Galaxy resulting in the generation of cosmic rays. The main neutrino annihilation processes are considered: i.e., nu --> f (f) over bar and nu --> W+W-. The condensation mechanism allows one to get information on the density distribution in the Galaxy halo without any recourse in an explicit dynamical halo model, and the resulting cosmic ray spectrum provides constraints on the heavy neutrino mass. The comparison of the predicted cosmic ray flux with the observed one excludes the heavy neutrino mass range 60 GeV < m(nu) < 115 GeV. Such a restriction leads to a bound on the present energy density of very heavy neutrinos which may be comparable to the corresponding baryonic one only in the range 115 GeV < m(nu) < 300 GeV. Our approach is valid for multicomponent dark matter and can be used for species that give even a negligible contribution to the critical cosmological density
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