We show evidence of particle acceleration at GEV energies associated directly with protons from the prompt emission of a long-duration M6-class solar flare on July 17, 2023, rather than from protons acceleration by shocks from its associated Coronal Mass Ejection (CME), which erupted with a speed of 1342 km/s. Solar Energetic Particles (SEP) accelerated by the blast have reached Earth, up to an almost S3 (strong) category of a radiation storm on the NOAA scale. Also, we show a temporal correlation between the fast rising of GOES-16 proton and muon excess at ground level in the count rate of the New-Tupi muon detector at the central SAA region. A Monte Carlo spectral analysis based on muon excess at New-Tupi is consistent with the acceleration of electrons and protons (ions) up to relativistic energies (GeV energy range) in the impulsive phase of the flare. In addition, we present another two marginal particle excesses (with low confidence) at ground-level detectors in correlation with the solar flare prompt emission.

We show that the energy-weighted angular (zenith, azimuth) distribution of extensive air showers (EAS), produced by Ultra High Energy (UHE) cosmic rays at the Pierre Auger Observatory (PAO), has a thrust axis almost transverse to the interplanetary magnetic field (IMF), with a thrust value Tp ≥ 0.64 ( where 1.0 means a perfect alignment and 0.5 isotropy). This behavior strongly suggests an effect of the IMF on the charged shower particles, producing additional lateral scattering. We discuss the weakening of the Earth's magnetic field during geomagnetic storms (30% of observational time) when the IMF becomes preponderant, strengthening the alignment.

We look for a diurnal anisotropy in the cosmic ray flow, using the Mexico-City Neutron Monitor (NM) detector, due to the Earth's orbital motion and predicted by Compton-Getting (C-G) in 1935, as a first-order relativistic effect. The Mexico-City NM's geographic latitude is not very high ($19.33^{\circ}$N), and it has a high cutoff geomagnetic rigidity (8.2 GV) and mountain altitude (2274 m asl) favoring the observation of the C-G effect. Furthermore, during the solar cycle minima, the galactic cosmic ray flux is maxima, and the solar magnetic field gets weakened, with a dipolar pattern. Its influence on cosmic rays reaching Earth is the smallest. Analysis of the combined counting rate during two solar minima, 2008 and 2019, from Mexico-city NM's data yields the C-G effect with an amplitude variation of (0.043$\pm$ 0.019)\%, and phase of (6.15$\pm$ 1.71) LT. The expected amplitude variation is 0.044\%, and the phase of 6.00 LT.

A period of minimum magnetic solar activity (such as June 2019) favors the observation of rare solar transient events, which would otherwise be lost in the magnetic vortex during a period of maximum solar activity. In this paper, we show that the most plausible explanation for the origin of an unexpected geomagnetic storm on June 8, 2019, is a small CME, ejected at low speed into a broad tube of an HCS on June 3, 2019, from an active region on the backside of the sun, and only detected by the STEREO Ahead Cor 2 probe. The magnetic entrapment of the flux-rope and the ejecta bulk, within the co-rotating HCS (already observed with other small slow CMEs), may be responsible for the large longitudinal deflection of this CME. Several remote observations, from the SECCHI and IMPACT instruments onboard STEREO-A, as well as the predictions of several heliospheric models, favor this scenario. We report the details of these observations.

We present an analysis of the short-term modulation (one rotation of Bartels-27 days) of the galactic cosmic rays (GCR) by the solar wind, based on the cosmic ray rates observed by the Pierre Auger Observatory (PAO) on their surface detectors in scaler mode. The incidence of GCR with energies below $\sim$ 50 TeV, at the top of the atmosphere, produces more than 90\% of the secondary particles registered at ground level, i.e., they are subject to solar modulation. The modulation is consistent with at least two components: The first is the modulation of the amplitude of the cosmic rays diurnal variation, anti-correlated with the solar-wind speed. The second one occurs during the high-speed stream (HSS), the baseline of the cosmic rays diurnal variation train falls, following the time profile of the solar-wind speed inversely. Based on the radial gradient of the cosmic ray diffusion theory and under some other premises, such as the latitude dependence on diurnal variation and the inclusion of drift processes in the propagation of GCR, a semi-empirical description of the modulation is possible to do, and it hereafter is called as Toy-model. Although the Toy-model does not include fluctuations due to propagation in the atmosphere, it provides satisfactory results when compared with the PAO scaler mode data. We present details of these observations as well as the Toy-model validation.

The significant deviations among observations and the expectations based on self-similar scaling model of galaxy clusters, especially up to redshift z≲ 0.4, constrain the evolution of the X-ray clusters scaling relations with the redshift, is claimed that in this redshift range, the data has a strong influence by selection bias. However, also suggests that some non-gravitational processes can be responsible for a weak or almost null evolution, at least to z≲ 0.4. This almost universality observed in X-ray galaxy clusters can be understood if we assume that the X-ray emission, results from thermal bremsstrahlung from a hot diffuse intracluster gas with temperatures about 10^8 K. A fraction of it would not be bound to the cluster and would escape as a wind. This hot wind can warm the local environment, the thermal bath where the cluster is immersed. This mechanism can put all the galaxy clusters within thermal baths, with almost the same effective temperature, independent of the cluster redshift and it can be effective for clusters with redshifts up to z∼ 0.4. Debye Gravitational Theory (DGT), allows obtaining a Generalized Faber-Jackson relation to described the galaxy clusters such as the M-σ and M-Tx relations as a function of the bath thermal temperature. We show that the DGT prediction to the M-σ relation, overlap the fit on data of an extensive spectroscopic survey of galaxy clusters with MMT/Hectospec, at 0.1≤ z ≤ 0.3. And the DGT predictions to the M-Tx relation almost overlap the fit on data from Canada France Hawaii Telescope Lensing Survey and XMM-CFHTLS surveys up to z∼ 0.47.

The conjectures of Hawking-Bekenstein of that gravity and temperature are closely related, was the beginning of the formulation of thermodynamic models of gravity. Using one of these models, we show that the thermal bath temperature of NGC1052-DF2 dwarf galaxy is about 6.5 K higher than the temperature of the thermal bath of the local dwarf galaxies. We claim that this temperature difference is responsible by the behavior of the NGC1052-DF2 galaxy to be apparently a galaxy with lack dark matter. This difference arises due to that the host galaxy of NGC1052-DF2, the elliptic galaxy NGC1052 is a LINER-type active galactic nucleus, with signals the intense starburst activity in the galaxy's center. Debye Gravitational Theory (DGT), allows obtaining a Generalized Faber-Jackson relation to described the dwarf galaxies and obtaining the velocity dispersion as a function of thermal bath temperature. DGT predict a velocity dispersion to NGC1052-DF2 dwarf galaxy in agreement with the very-low values reported in the literature. Also, DGT predicts that several, or maybe all dwarf galaxies from NGC1052 must have the same behavior than NGC1052-DF2 because they are immersed in thermal baths almost with the same temperature, this behavior already was observed in a second galaxy, the NGC1052-DF4 dwarf galaxy. Also, DGT predicts the same behavior, in all satellite galaxies orbiting galaxies with active nuclei.

On 2017 September 10 Neutron Monitors (NMs) apparatus located at ground level and high latitudes detected an increase in the counting rate associated to solar energetic particles (SEPs) emission from X8.2-class solar flare and its associated CME. This was the second-highest flare of the current solar cycle. The origin was the active region AR 12673 when it was located at the edge of the west solar disk, magnetically poorly connected with Earth. However, there was a peculiar condition: the solar protons accelerated by the CME shocks were injected within a heliospheric current sheet (HCS) region when Earth was crossing this region. We show that often HCS and SEPs propagation are closely related. If the source locations of SEPs are within or close to HCS, the HCS play the role of a Sun-Earth magnetic connection. SEPs drift around HCS paths, and SEPs are also drift in a wide range of longitudes by the HCSs. In some cases, and especially when Earth crosses the HCS sector, a fraction of these particles can reach Earth with a harder energetic particle flux, triggering a ground-level enhancement (GLE). The blast on 2017 September 10, which triggered the GLE #72, was the second in the current solar cycle. We show that the two GLEs, including all sub-GLEs observed in the current solar cycle, comes from solar explosions that happened within an HCS structure; this behavior is also observed in the GLEs of the previous solar cycle. In general, solar explosions from active regions poorly connected with Earth can trigger GLEs, through the mechanism described above. In all cases, the SEPs drift processes by HCS structures provides an efficient particle transport, allowing the observation of these solar transient events.

We report on the 22 – 23 June 2015 geomagnetic storm that occurred at the summer solstice. There have been fewer intense geomagnetic storms during the current solar cycle, Solar Cycle 24, than in the previous cycle. This situation changed after mid-June 2015, when one of the largest solar active regions (AR 12371) of Solar Cycle 24 that was located close to the central meridian, produced several coronal mass ejections (CMEs) associated with M-class flares. The impact of these CMEs on the Earth’s magnetosphere resulted in a moderate to severe G4-class geomagnetic storm on 22 – 23 June 2015 and a G2 (moderate) geomagnetic storm on 24 June. The G4 solstice storm was the second largest (so far) geomagnetic storm of Cycle 24. We highlight the ground-level observations made with the New-Tupi, Muonca, and the CARPET El Leoncito cosmic-ray detectors that are located within the South Atlantic Anomaly (SAA) region. These observations are studied in correlation with data obtained by space-borne detectors (ACE, GOES, SDO, and SOHO) and other ground-based experiments. The CME designations are taken from the Computer Aided CME Tracking (CACTus) automated catalog. As expected, Forbush decreases (FD) associated with the passing CMEs were recorded by these detectors. We note a peculiar feature linked to a severe geomagnetic storm event. The 21 June 2015 CME 0091 (CACTus CME catalog number) was likely associated with the 22 June summer solstice FD event. The angular width of CME 0091 was very narrow and measured \({\sim}\, 56^{\circ }\) degrees seen from Earth. In most cases, only CME halos and partial halos lead to severe geomagnetic storms. We perform a cross-check analysis of the FD events detected during the rise phase of Solar Cycle 24, the geomagnetic parameters, and the CACTus CME catalog. Our study suggests that narrow angular-width CMEs that erupt in a westward direction from the Sun–Earth line can lead to moderate and severe geomagnetic storms. We also report on the strong solar proton radiation storm that began on 21 June. We did not find a signal from this SEP at ground level. The details of these observations are presented.

O múon é a partícula carregada mais abundante da radiação cósmica secundária ao nível do mar. Por meio da leitura do fluxo de múons, físicos são capazes de analisar e identificar eventos solares transientes, que podem gerar impactos em nosso planeta. Os telescópios New-Tupi são telescópios capazes de efetuar a leitura do fluxo de múons que chegaá Terra. Esses telescópios geram um grande volume de dados que precisa ser consultado pelos físicos. Entretanto, atualmente tais telescópios armazenam todas as leituras realizadas em arquivos binários, o que dificulta a elaboração de consultas sobre os dados e sua posterior análise. O objetivo deste artigo é propor um Data Mart para os dados do telescópio New-Tupi, possibilitando aos físicos realizarem consultas mais complexas de forma fácil e com desempenho aceitável sem ter que recorrerá scripts ou programas de terceiros para implementar as consultas sobre os arquivos.

From June 2014 to February 2017, the Fermi LAT detected 46 gamma-ray bursts (GRBs) with photon energies above 20 MeV, and the trigger coordinates of seven of them were within the FoV of New-Tupi detector located in the central region of the South Atlantic Anomaly (SAA).We show in this paper that two of these seven GRBs have a probable GeV counterpart observed at ground level by New-Tupi detector. The first is GRB 160609A, a short duration GRB with a bright emission of photons over a broad energy range extending up to GeV energies. The second is GRB 160625B, a very long duration GRB, for which the Fermi LAT detected more than 300 photons with energies above 100 MeV in the ∼1 ks interval after the GBM trigger. In the first case, the signal at New-Tupi has a nominal significance of 3.5σ in the counting rate time profiles, within the T90(=5.6 s) duration on Fermi GBM. However, the effective significance is only 3.0σ. In the second case, New-Tupi detector registered at least two excess (peaks) with a nominal statistical significance of 4.8σ and 5.0σ at 438 s and 558 s after the trigger. The first is within the T90(=460 s) on Fermi GBM. Even so, the effective significance is only ∼2.0σ. In addition, from a Monte Carlo analysis, we show that the expected signal-to-noise ratio is compatible with the observation of GRB 160709A, only if the differential index of the GRB energy spectrum be equal or higher than −2.2 (a non-steep spectrum).

We report two ground-level observations, of geomagnetic storms of different origins; they are among the highest geomagnetic storms, in the solar Cycle 24. The first is St. Patrick ’ s Day storm on March 17, 2015, originated by the impact on Earth ’ s atmosphere of coronal mass ejections (CMEs), the storm reaching the condition of G4 (severe) level, in the NOAA geomagnetic scale. The second included the major geomagnetic storm whose origin is attributed to the interaction with the Earth of a High-Speed Stream (HSS) ahead of a positive polarity coronal hole on October 7, 2015. This storm reached the condition G3 (strong) level. We give emphasis to observations detected by the New-Tupi muon tele- scopes, located at sea level in Brazil (22.53 (cid:1) S, 43.13 (cid:1) W). We present a study of these observations in correlation with observations reported by multipoint space-based mea- surements, such as the ACE at Lagrange Point L1 and the geostationary GOES weather satellite, including two global geomagnetic indices and several ground-based detectors. Some considerations on the influence of these geomagnetic storms in the Earth weather are reported.

The thermal history of the Universe is introduced within the Debye Gravitational Theory (DGT), a thermodynamic theory of induced gravity, and allows to obtain the evolution of systems with the redshift. DGT reproduce the ESO VLT observations, showing falling outer rotation curves for galaxies at redshift above 0.77. A scaling law is observed in the radial acceleration relation (RAR) of galaxies. For accelerations smaller than ∼ 10^-10ms^-1 the observed acceleration g_obs decreases more slowly than acceleration generated by the baryonic mass g_bar, following always the relation g_obs∼√(g_bar). The RAR does not care about the specific properties of the galaxy, the relation exists in nearby high-mass elliptical and low-mass spheroidal galaxies. In this paper, through a straightforward analysis, we show that according to DGT, the RAR scaling law observed in nearby galaxies is broken, when are considered distant galaxies. The extreme case happen for galaxies at redshift above 0.77, because according to DGT, the galaxies have declining rotation curves, and the rotation velocity falling faster than the Keplerian-law curve. Then in this case g_obs decreases more faster than g_bar, this means that g_obs is systematically lower than g_bar. We show that DGT prediction for the RAR of galaxies at high redshift is in agreement from those obtained from the falling rotation curves observed by VLT telescope.

Nearby isolated galaxies ($z\sim 0$), are considered immerse within a thermal bath at 2.73 K. However the dwarf galaxies orbiting these galaxies are also subject to additional radiation from their hosts, so they are within a thermal bath slightly warmer. We claim that this thermal effect can explain several properties of the dwarf galaxies, such as their rotation curves, their radial acceleration relations (RAR) and why the velocity-mass dependence at the faint end of the Tully Fisher Relation (TFR) is steeper for these galaxies. In the Debye Gravitational Theory (DGT), the galaxies properties, such as the rotation curves, the RARs, and the TFRs are isothermal curves; they depend explicitly only of temperature, of the thermal bath in which are immersed. We show that the steep and faint end of the TFR is composed of a mixture of dwarf galaxies immersed in thermal baths with temperatures from 2.73 K to 3.80 K. A comparison among DGT's predictions for the dwarf galaxies relations with data obtained from the literature show a satisfactory agreement between them.

In this article we present results of studying the association between the muon flux variation at ground level, registered by the New-Tupi muon telescopes (\(22^{\circ} 53'00''~\mbox{S}, 43^{\circ} 06'13'~\mbox{W}\); 3 m above sea level), and the geomagnetic storm on 25 – 29 August 2015 that has raged for several days as a result of a coronal mass ejection (CME) impact on Earth’s magnetosphere. A sequence of events started with an M3.5 X-ray class flare on 22 August 2015 at 21:19 UTC. The New-Tupi muon telescopes observed a Forbush decrease (FD) triggered by this geomagnetic storm, which began on 26 August 2015. After Earth crossed the heliospheric current sheet (HCS), an increase in particle flux was observed on 28 August 2015 by spacecraft and ground-level detectors. The observed peak was in temporal coincidence with the impact of a high-speed stream (HSS). We study this increase, which has been observed with a significance above 1.5% by ground-level detectors in different rigidity regimes. We also estimate the lower limit of the energy fluence injected on Earth. In addition, we consider the origin of this increase, such as acceleration of particles by shock waves at the front of the HSS and the focusing effect of the HCS crossing. Our results show possible evidence of a prolonged energetic (up to GeV energies) particle injection within the Earth atmosphere system, driven by the HSS. In most cases, these injected particles are directed to the polar regions. However, the particles from the high-energy tail of the spectrum can reach mid-latitudes, and this could have consequences for the atmospheric chemistry. For instance, the creation of NOx species may be enhanced, and this can lead to increased ozone depletion. This topic requires further study.

The thermal history of the Universe is included in the Debye Gravitational Theory (DGT) to describe the speed of rotation of the galaxies. The DGT incorporate the temperature of Debye in the entropic gravitational theory. According to the DGT, the expression of the rotation of the galaxies is not a continuous function of the redshift, there is a discontinuity at ∼ 0.77. According to their redshift, the galaxies form two groups. (a) Those with redshift above 0.77 with declining rotation curves like R^β with β≤ -0.5 (Newtonian regime). (b) Those with redshift below 0.77 with rising rotation curves like R^β with β≥ 0 (Mondian regime). At z∼ 0.77 an extra boost (Dirac delta-like twisting force) led the galaxies to spin very fast.This scenario is consistent with a mysterious entity such as the dark energy and that at z∼ 0.77, in addition to accelerating the expansion, boosted the rotation of the galaxies again, inducing a transition between the Newtonian regime to the Mondian regime. It is possible to check that the characteristics on galaxy rotations provided by the DGT for a broad range of redshift from z∼ 4 to z=0 are in agreement with the observations. We believe that the change in the form of rotation of galaxies at z∼ 0.77 is new evidence for the hypothesis of dark energy.

The Debye model of the specific heat of solid at low temperatures is incorporate in the Entropic Gravity Theory (EGT). Rather of a smooth surface, the holographic screen is considered as an oscillating elastic membrane, with a continuous range of frequencies, that cuts off at a maximum (Debye) temperature, $T_D$. We show that at low temperatures $T < T_D$, the conservation of the equivalence principle in EGT requires a modification of the Davies-Unruh effect. While the maintenance of Davies-Unruh effect requires a violation of the equivalence principle. These two possibilities are equivalents, because both can emulate the same quantity of dark matter. However, in both cases, the central mechanism is the Davies-Unruh effect, this seems to indicate that the modification of the Davies-Unruh effect emulates dark matter which in turn can be see as a violation of the equivalence principle. This scenario is promising to explain why MOND theory works at very low temperatures (accelerations) regime, i. e., the galaxies sector. We also show that in the intermediate region, for temperatures slightly lower or slightly higher than Debye temperature, EGT predicts the mass-temperature relation of hot X-ray galaxy clusters.

An overview of gamma rays from space is presented. We highlight the most powerful astrophysical explosions, known as gamma-ray bursts. The main features observed in detectors onboard satellites are indicated. In addition, we also highlight a chronological description of the efforts made to observe their high energy counterpart at ground level. Some candidates of the GeV counterpart of gamma-ray bursts, observed by Tupi telescopes, are also presented.

Since 2014, a new detector (New-Tupi) consisting of four plastic scintillators (150 × 75 × 5 cm^3) placed in pairs and located in Niteroi, Rio de Janeiro, Brazil, has been used for the search of transient solar events and photomuons from gamma-ray bursts (GRBs). On September 15, 2015, at 21:18:24 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150915A (trigger 655721). The GRB light curve shows a weak complex structure of long duration T_90=164.7 ± 49.7 s, and a fluence in the 15-150 keV band of 8.0 ± 1.8 × 10^-7erg/cm^2. GRB 150915A was fortuitously located in the field of view of the New-Tupi detector, and a search for prompt emission in the GeV energy range is presented here. The analysis was made using the "scaler" or "single-particle" technique. The New-Tupi detector registered a counting rate excess peak of duration T_90=(6.1± 0.6) s with a signal significance (4.4± 0.5)σ, (and not 6.9σ as reported in the previous version). The signal is within the T90 duration of the Swift BAT GRB, with an estimated "excess" fluence of F_S(E>0.1 GeV)=1.3 ± 0.3 × 10^-6 erg/cm^2. This value can be considered the lower limit of the gamma ray fluence in the GeV energy region. However, the Poisson probability of the event to be a background fluctuation is 5.0 × 10^-6 and it appears in the counting rate of the New-Tupi detector with an annual rate ∼ 76. In addition, the signal has a significance of only 2σ in the time profiles with a bin above 2 seconds. Thus we conclude that the event has a high probability to be background fluctuation.

Far away from any sunspot, a bright flare erupted on November 1st, 2014, with onset at 4:44 UT and a duration of around three hours, causing a C2.7-class flare. The blast was associated with the sudden disappearance of a large dark solar filament. The rest of the filament flew out into space, forming the core of a massive CME. Despite the location of the explosion over the sun's southeastern region (near the eastern edge of the sun) not be geoeffective, a radiation storm, that is, solar energetic particles (SEP) started to reach the Earth around 14:00 UT, reaching the condition of an S1 (minor) radiation storm level on Nov. 2th. In coincidence with onset of the S1 radiation storm (SEP above 5 MeV), the Tupi telescopes located at $22^090'$S; $43^020'$W, within the South Atlantic Anomaly (SAA) detected a muon enhancement caused by relativistic protons from this solar blast. In addition an increase in the particle intensity was found also at South Pole neutron monitor. This means that there was a transverse propagation to the interplanetary magnetic field of energetic solar particles. However, we show that perpendicular diffusion alone cannot explain these observations, it is necessary a combination with further processes as a very high speed, at least of a fraction the CME shocks, close to the ecliptic plane.