Pub Date : 2025-02-07DOI: 10.1016/j.astropartphys.2025.103089
A. Lenni , M. Boezio , R. Munini , W. Menn , N. Marcelli , M.D. Ngobeni , D.C. Ndiitwani , I.I. Ramokgaba , M.S. Potgieter , O. Adriani , G.C. Barbarino , G.A. Bazilevskaya , R. Bellotti , E.A. Bogomolov , M. Bongi , V. Bonvicini , A. Bruno , F. Cafagna , D. Campana , P. Carlson , N. Zampa
The space-borne PAMELA experiment was launched on the 15th of June 2006 on board the Russian satellite Resurs-DK1 from the Baikonur Cosmodrome. The PAMELA instrument performed high-precision measurements of cosmic rays over a wide energy range until January 2016.
We present the yearly average deuteron spectra for the 23rd solar minimum (July 2006 – January 2009) and the first part of the 24th solar maximum (until September 2014). The deuterons were selected with a rigidity between 0.75 and 2.6 GV by combining the Time of Flight (ToF) and the tracker systems. The measured spectra display a rising trend toward the solar minimum followed by a decreasing trend as the solar maximum approaches. The corresponding deuteron-to-proton flux ratios show time dependence at the lowest rigidities, as expected due to the different charge-to-mass ratios and the different shapes of the respective local interstellar spectra. These results are significant for the fine-tuning of propagation and modulation models of cosmic rays through the heliosphere.
{"title":"The time evolution of the low-energy deuteron fluxes measured in Cosmic Rays with the PAMELA experiment from the 23rd solar minimum to the 24th solar maximum","authors":"A. Lenni , M. Boezio , R. Munini , W. Menn , N. Marcelli , M.D. Ngobeni , D.C. Ndiitwani , I.I. Ramokgaba , M.S. Potgieter , O. Adriani , G.C. Barbarino , G.A. Bazilevskaya , R. Bellotti , E.A. Bogomolov , M. Bongi , V. Bonvicini , A. Bruno , F. Cafagna , D. Campana , P. Carlson , N. Zampa","doi":"10.1016/j.astropartphys.2025.103089","DOIUrl":"10.1016/j.astropartphys.2025.103089","url":null,"abstract":"<div><div>The space-borne PAMELA experiment was launched on the 15th of June 2006 on board the Russian satellite Resurs-DK1 from the Baikonur Cosmodrome. The PAMELA instrument performed high-precision measurements of cosmic rays over a wide energy range until January 2016.</div><div>We present the yearly average deuteron spectra for the 23rd solar minimum (July 2006 – January 2009) and the first part of the 24th solar maximum (until September 2014). The deuterons were selected with a rigidity between 0.75 and 2.6 GV by combining the Time of Flight (ToF) and the tracker systems. The measured spectra display a rising trend toward the solar minimum followed by a decreasing trend as the solar maximum approaches. The corresponding deuteron-to-proton flux ratios show time dependence at the lowest rigidities, as expected due to the different charge-to-mass ratios and the different shapes of the respective local interstellar spectra. These results are significant for the fine-tuning of propagation and modulation models of cosmic rays through the heliosphere.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"168 ","pages":"Article 103089"},"PeriodicalIF":4.2,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-07DOI: 10.1016/j.astropartphys.2025.103090
R.G. Albuquerque , R.F.L. Holanda , I.E.T. R. Mendonça , P.S. Rodrigues da Silva
In this work, we test a possible redshift variation of the electron-to-proton mass ratio, , directly from galaxy cluster gas mass fraction measurements and type Ia supernovae observations. Our result reveals no variation of within 1 . From the point of view of Particle Physics, we can use the precision on these results to constrain the parameter space of models beyond the Standard Model of electroweak interactions. We exemplify this by focusing on a specific Two-Higgs doublet model (2HDM), where the second scalar doublet couples exclusively to leptons. An important parameter in the model concerns the ratio between its vacuum expectation values, defined by . In our approach, we can constrain the inverse parameter to an optimal value, , with the highest vacuum expectation value for 2HDM, , estimated at around GeV. Also, by taking into account the discrepancy in the anomalous magnetic moment of the muon found between theory and experiment, we can reduce the validity region for this model and establish bounds on the scalar masses, in light of our findings from galaxy cluster data for . This study contributes valuable insights to the understanding of the interface between Particle Physics and Astrophysics, establishing a new interrelationship between data on the large-scale structure of the Universe and subatomic Physics.
{"title":"Cosmological bounds on a possible electron-to-proton mass ratio variation and constraints in the lepton specific 2HDM","authors":"R.G. Albuquerque , R.F.L. Holanda , I.E.T. R. Mendonça , P.S. Rodrigues da Silva","doi":"10.1016/j.astropartphys.2025.103090","DOIUrl":"10.1016/j.astropartphys.2025.103090","url":null,"abstract":"<div><div>In this work, we test a possible redshift variation of the electron-to-proton mass ratio, <span><math><mrow><mi>μ</mi><mo>=</mo><msub><mrow><mi>m</mi></mrow><mrow><mi>e</mi></mrow></msub><mo>/</mo><msub><mrow><mi>m</mi></mrow><mrow><mi>p</mi></mrow></msub></mrow></math></span>, directly from galaxy cluster gas mass fraction measurements and type Ia supernovae observations. Our result reveals no variation of <span><math><mi>μ</mi></math></span> within 1 <span><math><mi>σ</mi></math></span>. From the point of view of Particle Physics, we can use the precision on these results to constrain the parameter space of models beyond the Standard Model of electroweak interactions. We exemplify this by focusing on a specific Two-Higgs doublet model (2HDM), where the second scalar doublet couples exclusively to leptons. An important parameter in the model concerns the ratio between its vacuum expectation values, defined by <span><math><mrow><mo>tan</mo><mi>β</mi><mo>≡</mo><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>/</mo><msub><mrow><mi>v</mi></mrow><mrow><mn>1</mn></mrow></msub></mrow></math></span>. In our approach, we can constrain the inverse parameter <span><math><mrow><mo>(</mo><mo>cot</mo><mi>β</mi><mo>)</mo></mrow></math></span> to an optimal value, <span><math><mrow><mrow><mo>(</mo><mo>cot</mo><mi>β</mi><mo>)</mo></mrow><mo>=</mo><mrow><mo>(</mo><mn>2</mn><mo>.</mo><mn>003</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>081</mn><mo>)</mo></mrow><mi>⋅</mi><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></mrow></math></span>, with the highest vacuum expectation value for 2HDM, <span><math><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>, estimated at around <span><math><mrow><mn>240</mn><mo>.</mo><mn>57</mn><mo>±</mo><mn>2</mn><mo>.</mo><mn>93</mn></mrow></math></span> GeV. Also, by taking into account the discrepancy in the anomalous magnetic moment of the muon found between theory and experiment, we can reduce the validity region for this model and establish bounds on the scalar masses, in light of our findings from galaxy cluster data for <span><math><mi>μ</mi></math></span>. This study contributes valuable insights to the understanding of the interface between Particle Physics and Astrophysics, establishing a new interrelationship between data on the large-scale structure of the Universe and subatomic Physics.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"168 ","pages":"Article 103090"},"PeriodicalIF":4.2,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-07DOI: 10.1016/j.astropartphys.2025.103091
Sara Martinelli , Tim Huege , Diego Ravignani , Harm Schoorlemmer
Measurements of radio signals induced by an astroparticle generating a cascade present a challenge because they are always superposed with an irreducible noise contribution. Quantifying these signals constitutes a non-trivial task, especially at low signal-to-noise ratios (SNR). Because of the randomness of the noise phase, the measurements can be either a constructive or a destructive superposition of signal and noise. To recover the electromagnetic energy of the cascade from the radio measurements, the energy fluence, i.e. the time integral of the Poynting vector, has to be estimated. Conventionally, noise subtraction in the time domain has been employed for energy fluence reconstruction, yielding significant biases at low signal-to-noise ratios. In several analyses, this bias is mitigated by imposing an SNR threshold cut, though this option is not ideal as it excludes valuable data. Additionally, the uncertainties derived from the conventional method are underestimated, even for large SNR values. To address this known issue, the uncertainties have so far typically been approximated and corrected by using ad-hoc terms. This work tackles these challenges by detailing a method to correctly estimate the uncertainties and lower the reconstruction bias in quantifying radio signals, thereby, ideally, eliminating the need for an SNR cut. The development of the method is based on a robust theoretical and statistical background, and the estimation of the fluence is performed in the frequency domain, allowing for the improvement of further analyses by providing access to frequency-dependent fluence estimation.
{"title":"Quantifying energy fluence and its uncertainty for radio emission from particle cascades in the presence of noise","authors":"Sara Martinelli , Tim Huege , Diego Ravignani , Harm Schoorlemmer","doi":"10.1016/j.astropartphys.2025.103091","DOIUrl":"10.1016/j.astropartphys.2025.103091","url":null,"abstract":"<div><div>Measurements of radio signals induced by an astroparticle generating a cascade present a challenge because they are always superposed with an irreducible noise contribution. Quantifying these signals constitutes a non-trivial task, especially at low signal-to-noise ratios (SNR). Because of the randomness of the noise phase, the measurements can be either a constructive or a destructive superposition of signal and noise. To recover the electromagnetic energy of the cascade from the radio measurements, the energy fluence, i.e. the time integral of the Poynting vector, has to be estimated. Conventionally, noise subtraction in the time domain has been employed for energy fluence reconstruction, yielding significant biases at low signal-to-noise ratios. In several analyses, this bias is mitigated by imposing an SNR threshold cut, though this option is not ideal as it excludes valuable data. Additionally, the uncertainties derived from the conventional method are underestimated, even for large SNR values. To address this known issue, the uncertainties have so far typically been approximated and corrected by using ad-hoc terms. This work tackles these challenges by detailing a method to correctly estimate the uncertainties and lower the reconstruction bias in quantifying radio signals, thereby, ideally, eliminating the need for an SNR cut. The development of the method is based on a robust theoretical and statistical background, and the estimation of the fluence is performed in the frequency domain, allowing for the improvement of further analyses by providing access to frequency-dependent fluence estimation.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"168 ","pages":"Article 103091"},"PeriodicalIF":4.2,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-03DOI: 10.1016/j.astropartphys.2025.103088
Xuan’ang Ye, Yi Zhang, Jiayin He, Shiping Zhao
Large-scale anisotropy, with amplitudes reaching approximately 0.1% at TeV energies, has been observed by multiple cosmic-ray experiments. The obstruction of cosmic rays by the Sun and Moon creates shadow effects, potentially impacting the observed cosmic ray anisotropy. To evaluate these effects, this study calculates the contributions of the Sun’s and Moon’s shadows to the overall cosmic-ray anisotropy in both local solar and sidereal time. The analysis reveals that in local sidereal time, the total 1D projection amplitude of the anisotropy is around 0.003%, which is significantly smaller than the observed cosmic-ray anisotropy. This indicates that the influence of the Sun’s and Moon’s shadows on cosmic-ray anisotropy analysis in local sidereal time is negligible. In contrast, in local solar time, the shadow-induced deficit appears in a very small time bin, with a magnitude comparable to that of the cosmic-ray solar anisotropy. This deficit could serve as a benchmark for validating anisotropy measurements in future facilities.
{"title":"The influence of Sun’s and Moon’s shadows on cosmic-ray anisotropy","authors":"Xuan’ang Ye, Yi Zhang, Jiayin He, Shiping Zhao","doi":"10.1016/j.astropartphys.2025.103088","DOIUrl":"10.1016/j.astropartphys.2025.103088","url":null,"abstract":"<div><div>Large-scale anisotropy, with amplitudes reaching approximately 0.1% at TeV energies, has been observed by multiple cosmic-ray experiments. The obstruction of cosmic rays by the Sun and Moon creates shadow effects, potentially impacting the observed cosmic ray anisotropy. To evaluate these effects, this study calculates the contributions of the Sun’s and Moon’s shadows to the overall cosmic-ray anisotropy in both local solar and sidereal time. The analysis reveals that in local sidereal time, the total 1D projection amplitude of the anisotropy is around 0.003%, which is significantly smaller than the observed cosmic-ray anisotropy. This indicates that the influence of the Sun’s and Moon’s shadows on cosmic-ray anisotropy analysis in local sidereal time is negligible. In contrast, in local solar time, the shadow-induced deficit appears in a very small time bin, with a magnitude comparable to that of the cosmic-ray solar anisotropy. This deficit could serve as a benchmark for validating anisotropy measurements in future facilities.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"168 ","pages":"Article 103088"},"PeriodicalIF":4.2,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-27DOI: 10.1016/j.astropartphys.2025.103087
Sandipan Dawn , A.K. Bakshi , P.K. Mohanty , Sujoy Chatterjee , B.K. Sahoo , B.K. Sapra
This study explores the potential of ground-based cosmic ray measurements to quantify solar weather parameters, specifically the total interplanetary magnetic field (Bt). A compact Tissue Equivalent Proportional Counter (TEPC), meant for measuring radiation doses in human tissue, was set up at Ny-Ålesund near the North Pole, a region with zero geomagnetic cut-off, which allows for detailed measurements of the different components of cosmic rays. The TEPC continuously monitored low Linear Energy Transfer (LET) cosmic ray components, mainly electrons, and photons during two different seasons: January to March (winter) and September (summer) in 2024. Monte Carlo simulations using PHITS and EXPACS were carried out to understand the changes in cosmic ray flux related to solar weather. To model the relationship between cosmic ray flux and Bt, two machine learning algorithms were used: Gaussian Process Regression (GPR) and Artificial Neural Networks (ANN). Cosmic ray neutron data from the Oulu neutron monitor, which is part of the global neutron monitor network for studying solar weather, were included in the model. Adding the low LET data increased the R² value in the GPR model from 0.81 to 0.90 on the training data, and in the ANN model from 0.76 to 0.88 in comparison to only neutron data, showing a significant improvement in predictive ability. The results show a significant correlation between cosmic ray variations and Bt, suggesting that ground based cosmic ray data collected at low geomagnetic cut-offs—as captured by the TEPC in Ny-Ålesund, can be a reliable way to estimate Bt, especially when satellite data is unavailable. This approach offers a promising, cost-effective method for continuous solar weather monitoring, providing valuable insights into the effect of solar activity on cosmic rays, in turn, helping to make space-based technological systems more resilient.
{"title":"Characterizing interplanetary magnetic field fluctuations at arctic using cosmic ray secondaries–An approach with machine learning","authors":"Sandipan Dawn , A.K. Bakshi , P.K. Mohanty , Sujoy Chatterjee , B.K. Sahoo , B.K. Sapra","doi":"10.1016/j.astropartphys.2025.103087","DOIUrl":"10.1016/j.astropartphys.2025.103087","url":null,"abstract":"<div><div>This study explores the potential of ground-based cosmic ray measurements to quantify solar weather parameters, specifically the total interplanetary magnetic field (B<sub>t</sub>). A compact Tissue Equivalent Proportional Counter (TEPC), meant for measuring radiation doses in human tissue, was set up at Ny-Ålesund near the North Pole, a region with zero geomagnetic cut-off, which allows for detailed measurements of the different components of cosmic rays. The TEPC continuously monitored low Linear Energy Transfer (LET) cosmic ray components, mainly electrons, and photons during two different seasons: January to March (winter) and September (summer) in 2024. Monte Carlo simulations using PHITS and EXPACS were carried out to understand the changes in cosmic ray flux related to solar weather. To model the relationship between cosmic ray flux and B<sub>t</sub>, two machine learning algorithms were used: Gaussian Process Regression (GPR) and Artificial Neural Networks (ANN). Cosmic ray neutron data from the Oulu neutron monitor, which is part of the global neutron monitor network for studying solar weather, were included in the model. Adding the low LET data increased the R² value in the GPR model from 0.81 to 0.90 on the training data, and in the ANN model from 0.76 to 0.88 in comparison to only neutron data, showing a significant improvement in predictive ability. The results show a significant correlation between cosmic ray variations and B<sub>t</sub>, suggesting that ground based cosmic ray data collected at low geomagnetic cut-offs—as captured by the TEPC in Ny-Ålesund, can be a reliable way to estimate B<sub>t</sub>, especially when satellite data is unavailable. This approach offers a promising, cost-effective method for continuous solar weather monitoring, providing valuable insights into the effect of solar activity on cosmic rays, in turn, helping to make space-based technological systems more resilient.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"167 ","pages":"Article 103087"},"PeriodicalIF":4.2,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.astropartphys.2025.103080
S. Ganesh
Many body gravity (MBG) is an alternate theory of gravity, which has been able to explain the galaxy rotation curves, the radial acceleration relation (RAR) and the wide binary stars (WBS). The genesis of MBG is a novel theory, which models systems with thermal gradients, by recasting the variation in the temperature as a variation in the metric. Merging the above concept with Einstein’s gravity, leads to the theory of thermal gravity in 5-D space–time–temperature. Thermal gravity when generalized for partially thermalized systems, results in the theory of MBG. The bullet cluster is supposed to be a smoking gun evidence for the presence of dark matter. However, this work demonstrates that the MBG theory can naturally explain the weak gravitational lensing effect of the bullet cluster, without the need for yet undiscovered baryonic matter or dark matter.
{"title":"Many body gravity and the bullet cluster","authors":"S. Ganesh","doi":"10.1016/j.astropartphys.2025.103080","DOIUrl":"10.1016/j.astropartphys.2025.103080","url":null,"abstract":"<div><div>Many body gravity (MBG) is an alternate theory of gravity, which has been able to explain the galaxy rotation curves, the radial acceleration relation (RAR) and the wide binary stars (WBS). The genesis of MBG is a novel theory, which models systems with thermal gradients, by recasting the variation in the temperature as a variation in the metric. Merging the above concept with Einstein’s gravity, leads to the theory of thermal gravity in 5-D space–time–temperature. Thermal gravity when generalized for partially thermalized systems, results in the theory of MBG. The bullet cluster is supposed to be a smoking gun evidence for the presence of dark matter. However, this work demonstrates that the MBG theory can naturally explain the weak gravitational lensing effect of the bullet cluster, without the need for yet undiscovered baryonic matter or dark matter.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"167 ","pages":"Article 103080"},"PeriodicalIF":4.2,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.astropartphys.2025.103079
M. Iori, F. Ferrarotto, L. Recchia, A. Girardi, R. Lunadei
In 2018 the Large Sized Telescope (LST-1) prototype, designed to be the lowest energy detector for the Cherenkov Telescope Array Observatory, was inaugurated at the Observatorio de Roque de Los Muchachos in La Palma, Canary Island and today three more are under construction, LST2-4. The LST camera, with 1855 photomultipliers (PMTs), requires precise and regular calibration. The camera calibration system (hereafter CaliBox), installed at the center of the telescope mirror dish, is equipped with a Q-switching 355 nm UV laser corresponding to the wavelength at which the maximum camera PMT quantum efficiency is achieved, a set of filters to guarantee a large dynamic range of photons on each camera pixel, and a Ulbricht sphere to spread uniformly the laser light over the camera plane 28 m away. The system is managed by an ODROID-C1+ single board computer that communicates through an Open Platform Communication Unified Architecture (OPCUA) protocol to the camera. The CaliBox is designed to fulfill the requirements needed for the calibration of the camera including the monitor of the photon flux to guarantee the quality of the CaliBox system of laser stability, uniform illumination and intensity range. In this paper, we present in detail the optical system, the monitor of the photon flux, the relevant electronic to monitor the device. The performance of the device, the photon flux monitoring, the evaluation of the photon flux sent to the camera obtained during tests performed in laboratory are shown.
{"title":"Test results of the optical calibration system for the Large Sized Telescope camera","authors":"M. Iori, F. Ferrarotto, L. Recchia, A. Girardi, R. Lunadei","doi":"10.1016/j.astropartphys.2025.103079","DOIUrl":"10.1016/j.astropartphys.2025.103079","url":null,"abstract":"<div><div>In 2018 the Large Sized Telescope (LST-1) prototype, designed to be the lowest energy detector for the Cherenkov Telescope Array Observatory, was inaugurated at the Observatorio de Roque de Los Muchachos in La Palma, Canary Island and today three more are under construction, LST2-4. The LST camera, with 1855 photomultipliers (PMTs), requires precise and regular calibration. The camera calibration system (hereafter CaliBox), installed at the center of the telescope mirror dish, is equipped with a Q-switching 355 nm UV laser corresponding to the wavelength at which the maximum camera PMT quantum efficiency is achieved, a set of filters to guarantee a large dynamic range of photons on each camera pixel, and a Ulbricht sphere to spread uniformly the laser light over the camera plane 28 m away. The system is managed by an ODROID-C1+ single board computer that communicates through an Open Platform Communication Unified Architecture (OPCUA) protocol to the camera. The CaliBox is designed to fulfill the requirements needed for the calibration of the camera including the monitor of the photon flux to guarantee the quality of the CaliBox system of laser stability, uniform illumination and intensity range. In this paper, we present in detail the optical system, the monitor of the photon flux, the relevant electronic to monitor the device. The performance of the device, the photon flux monitoring, the evaluation of the photon flux sent to the camera obtained during tests performed in laboratory are shown.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"167 ","pages":"Article 103079"},"PeriodicalIF":4.2,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-07DOI: 10.1016/j.astropartphys.2025.103078
Clara Escañuela Nieves, Felix Werner, Jim Hinton
High-energy cosmic rays generate air showers of secondary particles when they enter the Earth’s atmosphere. These highly energetic particles emit Cherenkov light that can be detected by Imaging Air Cherenkov Telescopes (IACTs) or Water-Cherenkov Detectors at mountain altitudes. Advances in the technique and larger collection areas have increased the rate at which air shower events can be captured, and the amount of data produced by modern high-time-resolution Cherenkov cameras. Therefore, Data Volume Reduction (DVR) has become critical for such telescope arrays, ensuring that only relevant information regarding the air shower is stored long-term. Given the vast amount of raw data, owing to the highest resolution and sensitivity, the upcoming Cherenkov Telescope Array Observatory (CTAO) will need robust data reduction strategies to ensure efficient data handling and a sustainable data analysis. The CTAO data rates needs to be reduced from hundreds of Petabytes (PB) per year to a few PB/year.
This paper presents DVR algorithms tailored for CTAO but also applicable for other existing IACT arrays, focusing on the selection of pixels likely to contain Cherenkov light from the air shower. It describes and evaluates multiple algorithms based on their signal efficiency, noise rejection, and shower reconstruction. With a focus on a time-based clustering algorithm which demonstrates a notable enhancement in the retention of low level signal pixels. Moreover, the robustness is assessed under different observing conditions, including detector defects. Through testing and analysis, it is shown that these algorithms offer promising solutions for efficient volume reduction in CTAO. They effectively address the challenges posed by the array’s very large data volume and ensure reliable data storage amidst varying observational conditions and hardware issues.
{"title":"A systematic assessment of Data Volume Reduction for IACTs","authors":"Clara Escañuela Nieves, Felix Werner, Jim Hinton","doi":"10.1016/j.astropartphys.2025.103078","DOIUrl":"10.1016/j.astropartphys.2025.103078","url":null,"abstract":"<div><div>High-energy cosmic rays generate air showers of secondary particles when they enter the Earth’s atmosphere. These highly energetic particles emit Cherenkov light that can be detected by Imaging Air Cherenkov Telescopes (IACTs) or Water-Cherenkov Detectors at mountain altitudes. Advances in the technique and larger collection areas have increased the rate at which air shower events can be captured, and the amount of data produced by modern high-time-resolution Cherenkov cameras. Therefore, <em>Data Volume Reduction</em> (DVR) has become critical for such telescope arrays, ensuring that only relevant information regarding the air shower is stored long-term. Given the vast amount of raw data, owing to the highest resolution and sensitivity, the upcoming Cherenkov Telescope Array Observatory (CTAO) will need robust data reduction strategies to ensure efficient data handling and a sustainable data analysis. The CTAO data rates needs to be reduced from hundreds of Petabytes (PB) per year to a few PB/year.</div><div>This paper presents DVR algorithms tailored for CTAO but also applicable for other existing IACT arrays, focusing on the selection of pixels likely to contain Cherenkov light from the air shower. It describes and evaluates multiple algorithms based on their signal efficiency, noise rejection, and shower reconstruction. With a focus on a time-based clustering algorithm which demonstrates a notable enhancement in the retention of low level signal pixels. Moreover, the robustness is assessed under different observing conditions, including detector defects. Through testing and analysis, it is shown that these algorithms offer promising solutions for efficient volume reduction in CTAO. They effectively address the challenges posed by the array’s very large data volume and ensure reliable data storage amidst varying observational conditions and hardware issues.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"167 ","pages":"Article 103078"},"PeriodicalIF":4.2,"publicationDate":"2025-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-30DOI: 10.1016/j.astropartphys.2024.103077
R. Alfaro , C. Alvarez , J.C. Arteaga-Velázquez , D. Avila Rojas , H.A. Ayala Solares , E. Belmont-Moreno , A. Bernal , K.S. Caballero-Mora , T. Capistrán , A. Carramiñana , S. Casanova , J. Cotzomi , S. Coutiño de León , E. De la Fuente , D. Depaoli , P. Desiati , N. Di Lalla , R. Diaz Hernandez , M.A. DuVernois , J.C. Díaz-Vélez , C. de León
We report the total energy spectrum of cosmic rays in the energy interval from to , which lies in the energy region where both direct and indirect cosmic ray experiments overlap. The all-particle spectrum was obtained from an unfolding analysis of 5.3 years of data collected with the High Altitude Water Cherenkov (HAWC) observatory for zenith angles smaller than or equal to 35°. The study was carried out in the framework of the QGSJET-II-04 hadronic interaction model. The measured spectrum confirms the presence of a knee-like feature at tens of TeV. In our analysis, the position of this softening is found at (stat.)(sys.). The measured spectral indices before and after the break are (stat.)(sys.) and (stat.)(sys.), respectively.
{"title":"A measurement of the all-particle energy spectrum of cosmic rays from 1013 to 1015eV using HAWC","authors":"R. Alfaro , C. Alvarez , J.C. Arteaga-Velázquez , D. Avila Rojas , H.A. Ayala Solares , E. Belmont-Moreno , A. Bernal , K.S. Caballero-Mora , T. Capistrán , A. Carramiñana , S. Casanova , J. Cotzomi , S. Coutiño de León , E. De la Fuente , D. Depaoli , P. Desiati , N. Di Lalla , R. Diaz Hernandez , M.A. DuVernois , J.C. Díaz-Vélez , C. de León","doi":"10.1016/j.astropartphys.2024.103077","DOIUrl":"10.1016/j.astropartphys.2024.103077","url":null,"abstract":"<div><div>We report the total energy spectrum of cosmic rays in the energy interval from <span><math><mrow><mn>10</mn><mspace></mspace><mtext>TeV</mtext></mrow></math></span> to <span><math><mrow><mn>1</mn><mspace></mspace><mtext>PeV</mtext></mrow></math></span>, which lies in the energy region where both direct and indirect cosmic ray experiments overlap. The all-particle spectrum was obtained from an unfolding analysis of 5.3 years of data collected with the High Altitude Water Cherenkov (HAWC) observatory for zenith angles smaller than or equal to 35°. The study was carried out in the framework of the QGSJET-II-04 hadronic interaction model. The measured spectrum confirms the presence of a knee-like feature at tens of TeV. In our analysis, the position of this softening is found at <span><math><mrow><mn>40</mn><mo>.</mo><mn>2</mn><mo>±</mo><mn>1</mn><mo>.</mo><mn>0</mn></mrow></math></span>(stat.)<span><math><msubsup><mrow></mrow><mrow><mo>−</mo><mn>6</mn><mo>.</mo><mn>4</mn></mrow><mrow><mo>+</mo><mn>6</mn><mo>.</mo><mn>2</mn></mrow></msubsup></math></span>(sys.)<span><math><mrow><mspace></mspace><mspace></mspace><mi>TeV</mi></mrow></math></span>. The measured spectral indices before and after the break are <span><math><mrow><msub><mrow><mi>γ</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>=</mo><mo>−</mo><mn>2</mn><mo>.</mo><mn>53</mn><mspace></mspace><mo>±</mo><mspace></mspace><mn>0</mn><mo>.</mo><mn>01</mn></mrow></math></span>(stat.)<span><math><msubsup><mrow></mrow><mrow><mo>−</mo><mn>0</mn><mo>.</mo><mn>05</mn></mrow><mrow><mo>+</mo><mn>0</mn><mo>.</mo><mn>04</mn></mrow></msubsup></math></span>(sys.) and <span><math><mrow><msub><mrow><mi>γ</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>=</mo><mo>−</mo><mn>2</mn><mo>.</mo><mn>71</mn><mspace></mspace><mo>±</mo><mspace></mspace><mn>0</mn><mo>.</mo><mn>01</mn></mrow></math></span>(stat.)<span><math><msubsup><mrow></mrow><mrow><mo>−</mo><mn>0</mn><mo>.</mo><mn>04</mn></mrow><mrow><mo>+</mo><mn>0</mn><mo>.</mo><mn>03</mn></mrow></msubsup></math></span>(sys.), respectively.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"167 ","pages":"Article 103077"},"PeriodicalIF":4.2,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-24DOI: 10.1016/j.astropartphys.2024.103076
Ambrose C. Eze , Romanus N.C. Eze , Augustine E. Chukwude , Fidelis O. Madu
MAXI J1535–571 underwent dramatic and transient outbursts accompanied by accretion flow. Hard X-radiations are produced due to thermal–and inverse–comptonization of soft photons by high-temperature electrons. The variations/fluctuations of components of the accretion flow rates and their fractional X-ray emissions/flux variability contributions at different epochs infer the spectral states. In this study, we utilized MAXI J1535–571 data observed by the three X-ray missions/detectors (MAXI/GSC, NuSTAR, and SWIFT/BAT) on the same and/or close-in epochs. Each detector's data were separately reduced and analyzed using HEASoft v6.28 and its software packages alongside the standard pipeline product software of each detector. Thereafter, the MAXI J1535–571 data were simultaneously fitted in XSPEC version 12.10.1f and modelled using selected analytical and phenomenological models (AP-model) to examine the photon index–NBMC saturation effect and variations of components of the accretion flow rates. Moreover, the TCAF model was used on MAXI J1535–571 data to determine the correlation of components of the accretion flow rates. The AP– and TCAF–models gave a statistically acceptable fit with a reduced Chi-squared value of ≤ 1.2, and their spectral results were compared. The best-fit photon index of ∼ 2.0–2.20 affirms that MAXI J1535–571 is in its rising phase; the hard-intermediate state. The correlation of mass accretion rates suggests that their variations/fluctuations could be responsible for the dynamics and geometry of the accretion flow.
{"title":"On the accretion flow and mass accretion rates/fluctuations in black hole candidate; MAXI J1535–571","authors":"Ambrose C. Eze , Romanus N.C. Eze , Augustine E. Chukwude , Fidelis O. Madu","doi":"10.1016/j.astropartphys.2024.103076","DOIUrl":"10.1016/j.astropartphys.2024.103076","url":null,"abstract":"<div><div>MAXI J1535–571 underwent dramatic and transient outbursts accompanied by accretion flow. Hard X-radiations are produced due to thermal–and inverse–comptonization of soft photons by high-temperature electrons. The variations/fluctuations of components of the accretion flow rates and their fractional X-ray emissions/flux variability contributions at different epochs infer the spectral states. In this study, we utilized MAXI J1535–571 data observed by the three X-ray missions/detectors (<em>MAXI/GSC, NuSTAR</em>, and <em>SWIFT/BAT</em>) on the same and/or close-in epochs. Each detector's data were separately reduced and analyzed using HEASoft v6.28 and its software packages alongside the standard pipeline product software of each detector. Thereafter, the MAXI J1535–571 data were simultaneously fitted in <em>XSPEC</em> version 12.10.1f and modelled using selected analytical and phenomenological models (AP-model) to examine the photon index–N<sub>BMC</sub> saturation effect and variations of components of the accretion flow rates. Moreover, the <em>TCAF</em> model was used on MAXI J1535–571 data to determine the correlation of components of the accretion flow rates. The <em>AP</em>– and <em>TCAF</em>–models gave a statistically acceptable fit with a reduced Chi-squared value of ≤ 1.2, and their spectral results were compared. The best-fit photon index of ∼ 2.0–2.20 affirms that MAXI J1535–571 is in its rising phase; the hard-intermediate state. The correlation of mass accretion rates suggests that their variations/fluctuations could be responsible for the dynamics and geometry of the accretion flow.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"166 ","pages":"Article 103076"},"PeriodicalIF":4.2,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号