An accurate MonteCarlo simulation of the deficit of primary cosmic rays in the direction of the Moon has been developed to interpret the observations reported in the TeV energy region until now. Primary particles are propagated trough the geomagnetic field in the Earth-Moon system. The algorithm is described and the contributions of the detector resolution and of the geomagnetic field are disentangled.
In the absence of an astrophysical standard candle, IceCube can study the deficit of cosmic rays from the direction of the Moon. The observation of this "Moon shadow" in the downgoing muon flux is an experimental verification of the absolute pointing accuracy and the angular resolution of the detector with respect to energetic muons passing through. The Moon shadow has been observed in the 40-string configuration of IceCube. This is the first stage of IceCube in which a Moon shadow analysis has been successful. Method, results, and some systematic error studies will be discussed.
Cosmic rays are hampered by the Moon and a deficit in its direction is expected (the so-called Moon shadow). The Moon shadow is an important method to determine the performance of an air shower array. In fact, the westward displacement of the shadow centre, due to the propagation of cosmic rays in the geomagnetic field, allows to calibrate the energy scale of the primary particles observed by the detector. In addition, the shape of the shadow allows a measurement of the angular resolution and the position of the deficit at high energy allows the evaluation of the pointing accuracy of the detec…
IceCube is the world's largest neutrino telescope, recently completed at the South Pole. As a proof of pointing accuracy, we look for the image of the Moon as a deficit in down-going cosmic ray muons, using techniques similar to those used in IceCube's astronomical point-source searches.
The Earth is subjected to a uniform flux of very-high-energy (VHE, E > 100 GeV) cosmic rays unless they are obscured by an object, such as the Moon, in which case a deficit or shadow is created. Since cosmic rays are charged this deficit is deflected by the Earth's magnetic field, enabling the rigidity of the obstructed cosmic rays to be determined. Measurement of the relative deficits of different species enables the positron fraction and the antiproton ratio to be measured. The April 15, 2014 lunar eclipse was visible with the VERITAS Cherenkov telescopes, which allowed (with special UV band…
Cosmic rays are hampered by the Moon and a deficit in its direction is expected (the so-called \emph{Moon shadow}). The Moon shadow is an important tool to determine the performance of an air shower array. In fact, the displacement of the shadow center, due to the bending effect of the Geomagnetic field on the propagation of cosmic rays, allows to set the energy scale of the primary particles inducing the showers observed by the detector. The shape of the shadow permits to determine the detector point spread function. The position of the deficit at high energy allows evaluating its pointing ac…
The shadowing of cosmic ray primaries by the the moon and sun was observed by the MINOS far detector at a depth of \unit[2070]{mwe} using 83.54 million cosmic ray muons accumulated over 1857.91 live-days. The shadow of the moon was detected at the \unit[5.6]{$σ$} level and the shadow of the sun at the \unit[3.8]{$σ$} level using a log-likelihood search in celestial coordinates. The moon shadow was used to quantify the absolute astrophysical pointing of the detector to be 0.17\pm 0.12^\circ. Hints of Interplanetary Magnetic Field effects were observed in both the sun and moon shadow.
The antimatter components measured in the Cosmic Ray (CR) flux are thought as secondary particles induced by the propagation of galactic CRs within the galaxy. Recent results from the PAMELA experiment show an unexpected increase of the positron electron ratio above 10 GeV. There could be different interpretations to explain that result, the most discussed ones being the signature of nearby compact astrophysical source(s) or of dark matter annihilation/decay. Probing the positron-fraction rise above 100 GeV would help to disentangle among different scenarios. Imaging Atmospheric Cherenkov Tele…
Cosmic rays are hampered by the Moon and a deficit in its direction is expected (the so-called \emph{Moon shadow}). The Moon shadow is an important tool to determine the performance of an air shower array. Indeed, the westward displacement of the shadow center, due to the bending effect of the geomagnetic field on the propagation of cosmic rays, allows the setting of the absolute rigidity scale of the primary particles inducing the showers recorded by the detector. In addition, the shape of the shadow permits to determine the detector point spread function, while the position of the deficit at…
The IceCube Neutrino Observatory is a cubic-kilometer-scaled detector located at the Geographic South Pole. The calibration of the directional reconstruction of neutrino-induced muons and the pointing accuracy of the detector have to be verified. For these purposes, the moon is used as a standard candle to not rely exclusively on simulated data: Cosmic rays get absorbed by the moon, which leads to a deficit of cosmic-ray-induced muons from the lunar direction that is measured with high statistics. The moon shadow analysis uses an unbinned maximum-likelihood method, which has been methodically …
Cosmic ray antiprotons provide an important probe for the study of cosmic-ray propagation in the interstellar space and to investigate the existence of Galactic dark matter. Cosmic rays are hampered by the Moon, therefore a deficit of cosmic rays in its direction is expected (the so-called "Moon shadow"). The Earth-Moon system acts as a magnetic spectrometer. In fact, due to the geomagnetic field the center of the Moon shifts westward by an amount depending on the primary cosmic ray energy. Paths of primary antiprotons are therefore deflected in an opposite sense in their way to the Earth. Thi…
Recent measurements of the cosmic-ray electron (e-) and positron (e+) fluxes show apparent excesses compared to the spectra expected by standard cosmic-ray (CR) propagation models in our galaxy. These excesses may be related to particle acceleration in local astrophysical objects, or to dark matter annihilation/decay. The e+/e- ratio (measured up to ~100 GeV) increases unexpectedly above 10 GeV and this may be connected to the excess measured in all-electron flux at 300-800 GeV. Measurement of this ratio at higher energies is a key parameter to understand the origin of these spectral anomalies…
The shadowing effect of the Moon and Sun in TeV cosmic rays has been measured with high statistical significance by several experiments. Unlike particles from directions close to the Moon, however, charged particles passing by the neighborhood of the Sun are affected not only by the geomagnetic but also by the solar near- and interplanetary-magnetic field. Since the latter undergoes a well-known 11-year cycle -- during which it can become highly disordered -- the cosmic-ray shadow cast by the Sun as observed on Earth is expected to change over time. We present an update of the analysis of the …
The Sun albedo of cosmic rays at GeVs energy has been discovered recently by FERMI satellite. They are traces of atmospheric CR hitting solar atmosphere and reflecting skimming gamma photons. Even if relevant for astrophysics, as being trace of atmospheric solar Cosmic Ray noises they cannot offer any signal of neutrino astronomy. On the contrary the Moon, with no atmosphere, may become soon a novel filtering calorimeter and an amplifier of energetic muon astronomical neutrinos (at TeV up to hundred TeV energy); these lepton tracks leave an imprint in their beta decay while in flight to Earth.…
An indirect measurement of the antiproton flux in cosmic rays is possible as the particles undergo deflection by the geomagnetic field. This effect can be measured by studying the deficit in the flux, or shadow, created by the Moon as it absorbs cosmic rays that are headed towards the Earth. The shadow is displaced from the actual position of the Moon due to geomagnetic deflection, which is a function of the energy and charge of the cosmic rays. The displacement provides a natural tool for momentum/charge discrimination that can be used to study the composition of cosmic rays. Using 33 months …
One of the main objectives of the ANTARES telescope is the search for point-like neutrino sources. Both the pointing accuracy and the angular resolution of the detector are important in this context and a reliable way to evaluate this performance is needed. In order to measure the pointing accuracy of the detector, one possibility is to study the shadow of the Moon, i.e. the deficit of the atmospheric muon flux from the direction of the Moon induced by the absorption of cosmic rays. Analysing the data taken between 2007 and 2016, the Moon shadow is observed with $3.5σ$ statistical significance…
We report on the observation of a significant deficit of cosmic rays from the direction of the Moon with the IceCube detector. The study of this "Moon shadow" is used to characterize the angular resolution and absolute pointing capabilities of the detector. The detection is based on data taken in two periods before the completion of the detector: between April 2008 and May 2009, when IceCube operated in a partial configuration with 40 detector strings deployed in the South Pole ice, and between May 2009 and May 2010 when the detector operated with 59 strings. Using two independent analysis met…
Cosmic ray antiprotons provide an important probe to study the cosmic ray propagation in the interstellar space and to investigate the existence of dark matter. Acting the Earth-Moon system as a magnetic spectrometer, paths of primary antiprotons are deflected in the opposite sense with respect to those of the protons in their way to the Earth. This effect allows, in principle, the search for antiparticles in the direction opposite to the observed deficit of cosmic rays due to the Moon (the so-called `Moon shadow'). The ARGO-YBJ experiment, located at the Yangbajing Cosmic Ray Laboratory (Tibe…
ANTARES is the largest undersea neutrino telescope and it has been taking data in its final configuration for more than ten years. On their journey to the Earth, cosmic rays can be absorbed by celestial objects, like the Sun, leading to a deficit in the atmospheric muon flux measured by the ANTARES detector, the so-called Sun "shadow" effect. This phenomenon can be used to evaluate fundamental telescope characteristics: the detector angular resolution and pointing accuracy. This work describes the study of the Sun "shadow" effect using the ANTARES data collected between 2008 and 2017. The stat…
UHE particle detection using the lunar Cherenkov technique aims to detect nanosecond pulses of Cherenkov emission which are produced during UHE cosmic ray and neutrino interactions in the Moon's regolith. These pulses will reach Earth-based telescopes dispersed, and therefore reduced in amplitude, due to their propagation through the Earth's ionosphere. To maximise the received signal to noise ratio and subsequent chances of pulse detection, ionospheric dispersion must therefore be corrected, and since the high time resolution would require excessive data storage this correction must be made i…
Cosmic rays in the inner solar system are subject to deflection by both the geomagnetic and interplanetary magnetic fields, and simultaneously interact with the Sun's photosphere resulting in the production of gamma rays. This phenomenon can be studied by observing the deficit ("shadow") in the cosmic ray flux from the direction of the Sun and searching for an excess photon signal above the isotropic background. The High Altitude Water Cherenkov (HAWC) Observatory in Mexico has been taking data on the solar disk at TeV energies since the end of 2014. We present our first efforts to estimate th…
Modeling the Effect of the Heliospheric Magnetic Field on Cosmic Ray Muon Shadows
Fermi National Accelerator Laboratory（费米国家加速器实验室）；Iowa State University（爱荷华州立大学）；University of Cincinnati（辛辛那提大学）；University of Oxford（牛津大学）；Cavendish Laboratory, University of Cambridge（剑桥大学卡文迪许实验室）；Lancaster University（兰卡斯特大学）；University of Texas at Austin（德克萨斯大学奥斯汀分校）；University of Wisconsin-Madison（威斯康星大学麦迪逊分校）；Universidade Federal de Goiás（戈亚斯联邦大学）；University of Manchester（曼彻斯特大学）；Tufts University（塔夫茨大学）
We report on the observation of a deficit in the cosmic ray flux from the directions of the Moon and Sun with five years of data taken by the IceCube Neutrino Observatory. Between May 2010 and May 2011 the IceCube detector operated with 79 strings deployed in the glacial ice at the South Pole, and with 86 strings between May 2011 and May 2015. A binned analysis is used to measure the relative deficit and significance of the cosmic ray shadows. Both the cosmic ray Moon and Sun shadows are detected with high statistical significance ($>10σ$) for each year. The results for the Moon shadow are con…
Cosmic ray antiprotons provide an important probe for the study of cosmic-ray propagation in the interstellar space and to investigate the existence of Galactic dark matter. The ARGO-YBJ experiment, located at the Yangbajing Cosmic Ray Laboratory (Tibet, P.R. China, 4300 m a.s.l., 606 g/cm$^2$), is the only experiment exploiting the full coverage approach at very high altitude presently at work. The ARGO-YBJ experiment is particularly effective in measuring the cosmic ray antimatter content via the observation of the cosmic rays Moon shadowing effect. Based on all the data recorded during the …
Cosmic ray antiprotons provide an important probe for the study of cosmic ray propagation in the interstellar space and to investigate the existence of Galactic dark matter. The ARGO-YBJ experiment is observing the Moon shadow with high statistical significance at an energy threshold of a few hundred GeV. Using all the data collected until November 2009, we set two upper limits on the antip/p flux ratio: 5% at an energy of 1.4 TeV and 6% at 5 TeV with a confidence level of 90%. In the few-TeV range the ARGO-YBJ results are the lowest available, useful to constrain models for antiproton product…
Observations of the time-dependent cosmic-ray Sun shadow have been proven as a valuable diagnostic for the assessment of solar magnetic field models. In this paper, seven years of IceCube data are compared to solar activity and solar magnetic field models. A quantitative comparison of solar magnetic field models with IceCube data on the event rate level is performed for the first time. Additionally, a first energy-dependent analysis is presented and compared to recent predictions. We use seven years of IceCube data for the Moon and the Sun and compare them to simulations on data rate level. Th…
We describe measurements of GeV and TeV cosmic rays with the High-Altitude Water Cherenkov Gamma-Ray Observatory, or HAWC. The measurements include the observation of the shadow of the moon; the observation of small-scale and large-scale angular clustering of the TeV cosmic rays; the prospects for measurement of transient solar events with HAWC; and the observation of Forbush decreases with the HAWC engineering array and HAWC-30.
The ANTARES detector, completed in 2008, is the largest neutrino telescope in the Northern hemisphere. It is located at a depth of 2.5 km in the Mediterranean Sea, 40 km off the Toulon shore. The scientific scope of the experiment is very broad, being the search for astrophysical neutrinos the main goal. In this paper we collect the 22 contributions of the ANTARES collaboration to the 32nd International Cosmic Ray Conference (ICRC 2011). At this stage of the experiment the scientific output is very rich and the contributions included in these proceedings cover the main physics results (steady …
We report on the measurement of the all-particle cosmic ray energy spectrum with the High Altitude Water Cherenkov (HAWC) Observatory in the energy range 10 to 500 TeV. HAWC is a ground based air-shower array deployed on the slopes of Volcan Sierra Negra in the state of Puebla, Mexico, and is sensitive to gamma rays and cosmic rays at TeV energies. The data used in this work were taken from 234 days between June 2016 to February 2017. The primary cosmic-ray energy is determined with a maximum likelihood approach using the particle density as a function of distance to the shower core. Introduci…
The Wide Field-of-View Cherenkov Telescope Array (WFCTA) and the Water Cherenkov Detector Arrays (WCDA) of LHAASO are designed to work in combination for measuring the energy spectra of various cosmic ray species over a very wide energy range from a few TeV to 10 PeV. The energy calibration of WCDA can be achieved with a proven technique of measuring the westward shift of the Moon shadow of galactic cosmic rays due to the geomagnetic field. This deflection angle $Δ$ is inversely proportional to the energy of the cosmic rays. The precise measurements of the shifts by WCDA allows us to calibrate…
