In this thesis a measurement of the high energy $γ$-ray flux between 200 MeV and 1 TeV with the Alpha Magnetic Spectrometer is presented. The Alpha Magnetic Spectrometer (AMS-02) is a multi-purpose particle detector mounted externally on the International Space Station.
Although primarily designed for the measurement of charged cosmic rays AMS-02 is capable of measuring high energy $γ$-rays in two complementary modes. Two independent analyses are presented in this thesis, one for each of the two modes. The event selection criteria and the associated resolution functions are presented in detail. The effective area is estimated from a full detector Monte-Carlo simulation and corrected for the most important differences between data and simulation. A full sky model for $γ$-rays is constructed from diffuse emission predictions and recent $γ$-ray source catalogs. A dedicated analysis of Fermi-LAT data is performed to fully enable a detailed comparison with the AMS result.
The measured flux of $γ$-rays is presented for various parts of the sky, including comparisons with Fermi-LAT data and with the constructed model. The inner galaxy is studied in detail, as an example of a region in which the photon flux is dominated by diffuse emission. The fluxes of several $γ$-ray producing sources, including Vela, Geminga and the Crab pulsar are shown. The Geminga pulsar is studied in detail, revealing its pulsed emission of $γ$-rays in the AMS-02 data, which allows to measure its frequency of rotation and to estimate its magnetic field strength and age. Finally, AMS-02 observed an outburst of the flaring blazar CTA-102 at the end of 2016.
We present a precise measurement of the combined electron plus positron flux from 0.5 GeV to 1 TeV, based on the analysis of the data collected by the Alpha Magnetic Spectrometer during the first 30 months of operations aboard the International Space Station. The statistics and the high resolution of AMS-02 detector provide a precise measurement of the flux. The flux is smooth and reveals new and distinct information. Above 30.2 GeV, the combined electron plus positron flux can be described accurately by a single power law.
Precision measurements by the Alpha Magnetic Spectrometer (AMS-02) on the International Space Station of the primary cosmic-ray electron flux and the positron flux will be discussed. The electron flux and the positron flux each require a description beyond a single power-law spectrum. Both the electron flux and the positron flux change their behavior at ~30 GeV but the fluxes are significantly different in their magnitude and energy dependence. Between 20 and 200 GeV the positron spectral index is significantly harder than the electron spectral index. The determination of the different behavio…
A precision measurement of the proton flux in primary cosmic rays with rigidity from 1 GV to 1.8 TV is presented based on 300 million events. The results show that the proton flux is smooth and exhibits no sharp structures with rigidity. The detailed variation with rigidity of the flux spectral index is presented. The spectral index is progressively hardening at high rigidities. Solar effects are also discussed.
The search for cosmic ray anisotropy has been performed using particles collected by the Alpha Magnetic Spectrometer after the first five years of operation. The positron to electron ratio is consistent with isotropy at all energies and angular scales. The limit on the dipole anisotropy at the 95% confidence level for energies above 16GeV is $δ<0.020$ for positrons and $δ<0.006$ for electrons. In the case of high rigidity protons the upper limit in the rigidity range from 80 to 1800GV is $δ<0.003$. No indication of seasonal excess is observed for all particle species within the present statist…
A precision measurement by AMS-02 of the positron fraction in primary cosmic rays is presented on this proceeding. Over the last two decades, there has been a strong interest in the cosmic ray positron fraction which exhibit an excess of high energy positrons whose origin is still highly uncertain. The Alpha Magnetic Spectrometer (AMS-02) is a general purpose high-energy particle physics detector operational on the International Space Station since May 2011. During its unique long duration mission AMS-02 is collecting large amount of data to study the behavior of cosmic ray electrons and posit…
We study the compatibility of Alpha Magnetic Spectrometer (AMS-02) data on the cosmic-ray (CR) positron fraction with data on the CR electron and positron spectra provided by PAMELA and Fermi LAT. We do that in terms of a novel propagation model in which sources are distributed in spiral arm patterns in agreement with astrophysical observations. While former interpretations assumed an unrealistically steep injection spectrum for astrophysical background electrons, the enhanced energy losses experienced by CR leptons due to the larger average source distance from Earth allow us to reproduce the…
A precision measurement by AMS of the antiproton-to-proton flux ratio in primary cosmic rays in the absolute rigidity range from 1 to 450 GV is presented based on $3.49\times10^5$ antiproton events and $2.42\times10^9$ proton events. Above $\sim60$ GV the antiproton to proton flux ratio is consistent with being rigidity independent. A decreasing behaviour is expected for this ratio considering the traditional models for the secondary antiproton flux.
Knowledge of the precise rigidity dependence of the carbon flux is important in understanding the origin, acceleration and propagation of cosmic rays. The current status of the measurement of the carbon flux in cosmic rays with rigidity from 1.9 GV to 2.6 TV, based on 8.3 million events collected by the Alpha Magnetic Spectrometer during the first 5 years of operation, is presented.
This thesis presents an analysis of the cosmic-ray electron and positron flux using the AMS-02 detector on the International Space Station as a function of time and energy. The time-averaged flux is integrated over 6.5 years of AMS-02 science data and provides the electron and positron flux with unprecedented accuracy, covering the energy range from 0.5 GeV to 1 TeV. In total 28.39 million events were identified as electrons and 1.95 million as positrons. For each of the 88 Bartels rotation periods (27 days), within the 6.5 years, an individual electron and positron flux is derived spanning th…
I review latest results from AMS on electrons and positrons in primary cosmic rays in the GeV to TeV energy range. Separate fluxes for electrons and positrons as well as their sum are presented. Neither of the fluxes is compatible with a simple power law. New data on the fraction of positrons in the joint electron and positron flux are also presented, which extend the energy range of our previous observation and increase its precision. The new results show, for the first time, that above about 200 GeV the positron fraction no longer exhibits an increase with energy. The results confirm that a …
AMS-02 is a wide acceptance high-energy physics experiment installed on the International Space Station in May 2011 and it has been operating continuously since then. AMS-02 is able to separate cosmic rays light nuclei ($1\leq Z \leq 8$) with contaminations less than $10^{-3}$. The ratio between the cosmic rays Boron and Carbon fluxes is known to be very sensitive to the properties of the propagation of cosmic rays in the Galaxy, being Boron a secondary product of spallation on the interstellar medium of heavier primary elements such as Carbon and Oxygen. A precise measurement reaching the TeV…
The next generation magnetic spectrometer in space, AMS-100, is designed to have a geometrical acceptance of $100\,\mathrm{m}^2\,\mathrm{sr}$ and to be operated for at least ten years at the Sun-Earth Lagrange Point 2. Compared to existing experiments, it will improve the sensitivity for the observation of new phenomena in cosmic rays, and in particular in cosmic antimatter, by at least a factor of 1000. The magnet design is based on high temperature superconductor tapes, which allow the construction of a thin solenoid with a homogeneous magnetic field of 1 Tesla inside. The inner volume is in…
A measurement of the dipole anisotropy in galactic coordinates for different charged cosmic rays has been performed with the Alpha Magnetic Spectrometer (AMS) onboard the International Space Station (ISS). Results are presented for the first 7.5 years of data taking for protons, Helium, Carbon and Oxygen, and 6.5 years for positrons and electrons. All the species are found to be consistent with isotropy and upper limits to the dipole amplitude have been computed. In particular, for energies above 16 GeV a limit of delta < 1.9% and delta < 0.5% at the 95% C.I. is found for positrons and electro…
Monitor of All-sky X-ray Image (MAXI) is mounted on the International Space Station (ISS). Since 2009 it has been scanning the whole sky in every 92 minutes with ISS rotation. Due to high particle background at high latitude regions the carbon anodes of three GSC cameras were broken. We limit the GSC operation to low-latitude region around equator. GSC is suffering a double high background from Gamma-ray altimeter of Soyuz spacecraft. MAXI issued the 37-month catalog with 500 sources above ~0.6 mCrab in 4-10 keV. MAXI issued 133 to Astronomers Telegram and 44 to Gammaray burst Coordinated Netw…
The Fermi Large Area Telescope has detected over 260 gamma-ray pulsars. About one quarter of these are labeled as radio-quiet. In the population of nonrecycled gamma-ray pulsars, the fraction of radio-quiet pulsars is higher, about one half. Most radio observations of gamma-ray pulsars have been performed at frequencies between 300 MHz and 2 GHz. However, pulsar radio fluxes increase rapidly with decreasing frequency, and their radio beams often broaden at low frequencies. As a consequence, some of these pulsars might be detectable at low radio frequencies even when no radio flux is detected a…
Mini-EUSO will observe the Earth in the UV range (300 - 400 nm) offering the opportunity to study a variety of atmospheric events such as Transient Luminous Events (TLEs), meteors and marine bioluminescence. Furthermore it aims to search for Ultra High Energy Cosmic Rays (UHECR) above $10^{21}$ eV and Strange Quark Matter (SQM). The detector is expected to be launched to the International Space Station in August 2019 and look at the Earth in nadir mode from the UV-transparent window of the Zvezda module of the International Space Station. The instrument comprises a compact telescope with a lar…
In this paper, we present the measurement of the energy spectra of carbon and oxygen in cosmic rays based on observations with the Calorimetric Electron Telescope (CALET) on the International Space Station from October 2015 to October 2019. Analysis, including the detailed assessment of systematic uncertainties, and results are reported. The energy spectra are measured in kinetic energy per nucleon from 10 GeV$/n$ to 2.2 TeV$/n$ with an all-calorimetric instrument with a total thickness corresponding to 1.3 nuclear interaction length. The observed carbon and oxygen fluxes show a spectral index…
A precise measurement of the cosmic-ray proton spectrum with the Calorimetric Electron Telescope (CALET) is presented in the energy interval from 50 GeV to 60 TeV, and the observation of a softening of the spectrum above 10 TeV is reported. The analysis is based on the data collected during $\sim$6.2 years of smooth operations aboard the International Space Station and covers a broader energy range with respect to the previous proton flux measurement by CALET, with an increase of the available statistics by a factor of $\sim$2.2. Above a few hundred GeV we confirm our previous observation of a…
The Calorimetric Electron Telescope (CALET), in operation on the International Space Station since 2015, collected a large sample of cosmic-ray iron over a wide energy interval. In this Letter a measurement of the iron spectrum is presented in the range of kinetic energy per nucleon from 10 GeV$/n$ to 2.0 TeV$/n$ allowing the inclusion of iron in the list of elements studied with unprecedented precision by space-borne instruments. The measurement is based on observations carried out from January 2016 to May 2020. The CALET instrument can identify individual nuclear species via a measurement of…
In this paper, we present the analysis and results of a direct measurement of the cosmic-ray proton spectrum with the CALET instrument onboard the International Space Station, including the detailed assessment of systematic uncertainties. The observation period used in this analysis is from October 13, 2015 to August 31, 2018 (1054 days). We have achieved the very wide energy range necessary to carry out measurements of the spectrum from 50 GeV to 10 TeV covering, for the first time in space, with a single instrument the whole energy interval previously investigated in most cases in separate s…
The Miniature X-ray Solar Spectrometer (MinXSS) are twin 3U CubeSats. The first of the twin CubeSats (MinXSS-1) launched in December 2015 to the International Space Station for deployment in mid-2016. Both MinXSS CubeSats utilize a commercial off the shelf (COTS) X-ray spectrometer from Amptek to measure the solar irradiance from 0.5 to 30 keV with a nominal 0.15 keV FWHM spectral resolution at 5.9 keV, and a LASP-developed X-ray broadband photometer with similar spectral sensitivity. MinXSS design and development has involved over 40 graduate students supervised by professors and professional…
The CALorimetric Electron Telescope (CALET) is a high-energy astroparticle physics space experiment installed on the International Space Station (ISS), developed and operated by Japan in collaboration with Italy and the United States. The CALET mission goals include the investigation of possible nearby sources of high-energy electrons, of the details of galactic particle acceleration and propagation, and of potential signatures of dark matter. CALET measures the cosmic-ray electron + positron flux up to 20 TeV, gamma-rays up to 10 TeV, and nuclei with Z=1 to 40 up to 1,000 TeV for the more abu…
Mini-EUSO is a telescope launched on board the International Space Station in 2019 and currently located in the Russian section of the station. Main scientific objectives of the mission are the search for nuclearites and Strange Quark Matter, the study of atmospheric phenomena such as Transient Luminous Events, meteors and meteoroids, the observation of sea bioluminescence and of artificial satellites and man-made space debris. It is also capable of observing Extensive Air Showers generated by Ultra-High Energy Cosmic Rays with an energy above 10$^{21}$ eV and detect artificial showers generat…
First results of a cosmic-ray electron + positron spectrum, from 10 GeV to 3 TeV, is presented based upon observations with the CALET instrument on the ISS starting in October, 2015. Nearly a half million electron + positron events are included in the analysis. CALET is an all-calorimetric instrument with total vertical thickness of 30 $X_0$ and a fine imaging capability designed to achieve a large proton rejection and excellent energy resolution well into the TeV energy region. The observed energy spectrum over 30 GeV can be fit with a single power law with a spectral index of -3.152 $\pm$ 0.…
Direct Measurement of the Cosmic-Ray Helium Spectrum from 40 GeV to 250 TeV with the Calorimetric Electron Telescope on the International Space Station
To date, only 69 pulsars have been identified with a detected pulsed radio emission below 100 MHz. A LOFAR-core LBA census and a dedicated campaign with the Nançay LOFAR station in stand-alone mode were carried out in the years 2014$-$2017 in order to extend the known population in this frequency range. In this paper, we aim to extend the sample of known radio pulsars at low frequencies and to produce a catalogue in the frequency range of 25-80 MHz. This will allow future studies to probe the local Galactic pulsar population, in addition to helping explain their emission mechanism, better char…
Mini-EUSO is a detector observing the Earth in the ultraviolet band from the International Space Station through a nadir-facing window, transparent to the UV radiation, in the Russian Zvezda module. Mini-EUSO main detector consists in an optical system with two Fresnel lenses and a focal surface composed of an array of 36 Hamamatsu Multi-Anode Photo-Multiplier tubes, for a total of 2304 pixels, with single photon counting sensitivity. The telescope also contains two ancillary cameras, in the near infrared and visible ranges, to complement measurements in these bandwidths. The instrument has a …
We present the measurement of the energy dependence of the boron flux in cosmic rays and its ratio to the carbon flux \textcolor{black}{in an energy interval from 8.4 GeV$/n$ to 3.8 TeV$/n$} based on the data collected by the CALorimetric Electron Telescope (CALET) during $\sim 6.4$ years of operation on the International Space Station. An update of the energy spectrum of carbon is also presented with an increase in statistics over our previous measurement. The observed boron flux shows a spectral hardening at the same transition energy $E_0 \sim 200$ GeV$/n$ of the C spectrum, though B and C …
Extended results on the cosmic-ray electron + positron spectrum from 11 GeV to 4.8 TeV are presented based on observations with the Calorimetric Electron Telescope (CALET) on the International Space Station utilizing the data up to November 2017. The analysis uses the full detector acceptance at high energies, approximately doubling the statistics compared to the previous result. CALET is an all-calorimetric instrument with a total thickness of 30 $X_0$ at normal incidence and fine imaging capability, designed to achieve large proton rejection and excellent energy resolution well into the TeV …
The relative abundance of cosmic ray nickel nuclei with respect to iron is by far larger than for all other trans-iron elements, therefore it provides a favorable opportunity for a low background measurement of its spectrum. Since nickel, as well as iron, is one of the most stable nuclei, the nickel energy spectrum and its relative abundance with respect to iron provide important information to estimate the abundances at the cosmic ray source and to model the Galactic propagation of heavy nuclei. However, only a few direct measurements of cosmic-ray nickel at energy larger than $ \sim$ 3 GeV/n…
Alpha Magnetic Spectrometer (AMS-02) is a general purpose high energy particle detector which will be deployed on the International Space Station (ISS) at the end of 2010 - beginning of 2011 to conduct a unique 10 to 18 year mission of fundamental physics research in space. Among the physics objectives of AMS are a search for an understanding of Dark Matter, Antimatter, the origin of cosmic rays and the exploration of new physics phenomena not possible to study from ground based experiments. This article reviews the status of the AMS-02 detector construction, detector calibration results as we…
The Alpha Magnetic Spectrometer (AMS) is a new generation high-energy physics experiment installed on the International Space Station in May 2011 and operating continuously since then. Using an unprecedently large collection of particles and antiparticles detected in space, AMS is performing precision measurements of cosmic ray energy spectra and composition. In this paper, we discuss the physics of solar modulation in Galactic cosmic rays that can be investigated with AMS my means of dedicated measurements on the time-dependence of cosmic-ray proton, helium, electron and positron fluxes.
