ABSTRACT
Addressing the origin of the astrophysical neutrino flux observed by IceCube is of paramount importance. Gamma-Ray Bursts (GRBs) are among the few astrophysical sources capable of achieving ...the required energy to contribute to such neutrino flux through pγ interactions. In this work, ANTARES data have been used to search for upward going muon neutrinos in spatial and temporal coincidence with 784 GRBs occurred from 2007 to 2017. For each GRB, the expected neutrino flux has been calculated in the framework of the internal shock model and the impact of the lack of knowledge on the majority of source redshifts and on other intrinsic parameters of the emission mechanism has been quantified. It is found that the model parameters that set the radial distance where shock collisions occur have the largest impact on neutrino flux expectations. In particular, the bulk Lorentz factor of the source ejecta and the minimum variability time-scale are found to contribute significantly to the GRB-neutrino flux uncertainty. For the selected sources, ANTARES data have been analysed by maximizing the discovery probability of the stacking sample through an extended maximum-likelihood strategy. Since no neutrino event passed the quality cuts set by the optimization procedure, 90 per cent confidence level upper limits (with their uncertainty) on the total expected diffuse neutrino flux have been derived, according to the model. The GRB contribution to the observed diffuse astrophysical neutrino flux around 100 TeV is constrained to be less than 10 per cent.
The ANTARES detector is at present the most sensitive neutrino telescope in the northern hemisphere. The highly significant cosmic neutrino excess observed by the Antarctic IceCube detector can be ...studied with ANTARES, exploiting its complementing field of view, exposure, and lower energy threshold. Searches for an all-flavor diffuse neutrino signal, covering nine years of ANTARES data taking, are presented in this Letter. Upward-going events are used to reduce the atmospheric muon background. This work includes for the first time in ANTARES both track-like (mainly and shower-like (mainly ) events in this kind of analysis. Track-like events allow for an increase of the effective volume of the detector thanks to the long path traveled by muons in rock and/or sea water. Shower-like events are well reconstructed only when the neutrino interaction vertex is close to, or inside, the instrumented volume. A mild excess of high-energy events over the expected background is observed in nine years of ANTARES data in both samples. The best fit for a single power-law cosmic neutrino spectrum, in terms of per-flavor flux at 100 TeV, is 10−18 GeV−1 cm−2 s−1 sr−1 with spectral index . The null cosmic flux assumption is rejected with a significance of 1.6 .
ABSTRACT
We present our follow-up observations with GRANDMA of transient sources revealed by the Zwicky Transient Facility (ZTF). Over a period of six months, all ZTF alerts were examined in real ...time by a dedicated science module implemented in the Fink broker, which will be used in filtering of transients discovered by the Vera C. Rubin Observatory. In this article, we present three selection methods to identify kilonova candidates. Out of more than 35 million alerts, a hundred sources have passed our selection criteria. Six were then followed-up by GRANDMA (by both professional and amateur astronomers). The majority were finally classified either as asteroids or as supernovae events. We mobilized 37 telescopes, bringing together a large sample of images, taken under various conditions and quality. To complement the orphan kilonova candidates, we included three additional supernovae alerts to conduct further observations during summer 2021. We demonstrate the importance of the amateur astronomer community that contributed images for scientific analyses of new sources discovered in a magnitude range r′ = 17 − 19 mag. We based our rapid kilonova classification on the decay rate of the optical source that should exceed 0.3 mag d−1. GRANDMA’s follow-up determined the fading rate within 1.5 ± 1.2 d post-discovery, without waiting for further observations from ZTF. No confirmed kilonovae were discovered during our observing campaign. This work will be continued in the coming months in the view of preparing for kilonova searches in the next gravitational-wave observing run O4.
The Protvino accelerator facility located in the Moscow region, Russia, is in a good position to offer a rich experimental research program in the field of neutrino physics. Of particular interest is ...the possibility to direct a neutrino beam from Protvino towards the KM3NeT/ORCA detector, which is currently under construction in the Mediterranean Sea 40 km offshore Toulon, France. This proposal is known as P2O. Thanks to its baseline of 2595 km, this experiment would yield an unparalleled sensitivity to matter effects in the Earth, allowing for the determination of the neutrino mass ordering with a high level of certainty after only a few years of running at a modest beam intensity of
≈
90
kW
. With a prolonged exposure (
≈
1500
kW
year
), a
2
σ
sensitivity to the leptonic CP-violating Dirac phase can be achieved. A second stage of the experiment, comprising a further intensity upgrade of the accelerator complex and a densified version of the ORCA detector (Super-ORCA), would allow for up to a
6
σ
sensitivity to CP violation and a
10
∘
-
17
∘
resolution on the CP phase after 10 years of running with a 450 kW beam, competitive with other planned experiments. The initial composition and energy spectrum of the neutrino beam would need to be monitored by a near detector, to be constructed several hundred meters downstream from the proton beam target. The same neutrino beam and near detector set-up would also allow for neutrino-nucleus cross section measurements to be performed. A short-baseline sterile neutrino search experiment would also be possible.
The results of three different searches for neutrino candidates, associated with the IceCube-170922A event or from the direction of TXS 0506+056, by the ANTARES neutrino telescope, are presented. The ...first search refers to the online follow-up of the IceCube alert; the second is based on the standard time-integrated method employed by the Collaboration to search for point-like neutrino sources; the third uses information from the IceCube time-dependent analysis that reported bursting activity centered on 2014 December 13, as input for an ANTARES time-dependent analysis. The online follow-up and the time-dependent analysis yield no events related to the source. The time-integrated study performed over a period from 2007 to 2017 fits 1.03 signal events, which corresponds to a p-value of 3.4% (not considering trial factors). Only for two other astrophysical objects in our candidate list has a smaller p-value been found. When considering that 107 sources have been investigated, the post-trial p-value for TXS 0506+056 corresponds to 87%.
ABSTRACT
GRB 230812B is a bright and relatively nearby (z = 0.36) long gamma-ray burst (GRB) that has generated significant interest in the community and has thus been observed over the entire ...electromagnetic spectrum. We report over 80 observations in X-ray, ultraviolet, optical, infrared, and submillimetre bands from the GRANDMA (Global Rapid Advanced Network for Multimessenger Addicts) network of observatories and from observational partners. Adding complementary data from the literature, we then derive essential physical parameters associated with the ejecta and external properties (i.e. the geometry and environment) of the GRB and compare with other analyses of this event. We spectroscopically confirm the presence of an associated supernova, SN2023pel, and we derive a photospheric expansion velocity of v ∼ 17 × 103 km s−1. We analyse the photometric data first using empirical fits of the flux and then with full Bayesian inference. We again strongly establish the presence of a supernova in the data, with a maximum (pseudo-)bolometric luminosity of 5.75 × 1042 erg s−1, at $15.76^{+0.81}_{-1.21}$ d (in the observer frame) after the trigger, with a half-max time width of 22.0 d. We compare these values with those of SN1998bw, SN2006aj, and SN2013dx. Our best-fitting model favours a very low density environment ($\log _{10}({n_{\rm ISM}/{\rm cm}^{-3}}) = -2.38^{+1.45}_{-1.60}$) and small values for the jet’s core angle $\theta _{\rm core} = 1.54^{+1.02}_{-0.81} \ \rm {deg}$ and viewing angle $\theta _{\rm obs} = 0.76^{+1.29}_{-0.76} \ \rm {deg}$. GRB 230812B is thus one of the best observed afterglows with a distinctive supernova bump.
black We present a campaign designed to train the Global Rapid Advanced Network Devoted to the Multi-messenger Addicts (GRANDMA) network and its infrastructure to follow up on transient alerts and ...detect their early afterglows.
In preparation for O4 II campaign, we focused on gamma-ray burst (GRB) alerts since they are expected to serve as the electromagnetic counterpart of gravitational-wave events.
Our goal was to improve our response to the alerts and to start prompt observations as soon as possible, so that we may better prepare the GRANDMA network for the fourth observational run of LIGO-Virgo-Kagra (launched at the end of May 2023) and future missions such as SM. black We set up a dedicated infrastructure and organized a rota of follow-up advocates (FAs) to guarantee round-the-clock assistance to our telescope teams, with an aim to receive, manage, and send out observational plans
to our partner telescopes.
To ensure a large number of observations, we focused on Swift GRBs whose localization errors were generally smaller than the GRANDMA telescopes' field of view. This allowed us to bypass the transient identification process and focus on the reaction time and efficiency of the network. black During the 'Ready for O4 II' phase, 11 Swift /INTEGRAL GRB triggers were selected. Of these, nine fields had been observed and three afterglows had been detected (GRB\,220403B, GRB\,220427A, GRB\,220514A) with 17 GRANDMA telescopes and 17 amateur astronomers from the citizen science project Kilonova-Catcher. Here, we highlight the GRB\,220427A analysis, where our long-term follow-up of the host galaxy allowed us to obtain a photometric redshift of $z=0.82 and its lightcurve evolution, as well as to fit the decay slope of the afterglows and study the properties of the host galaxy. black During this eight-week-long GRB follow-up campaign, we successfully fulfilled our goal of training telescope teams for O4 and improving the associated technical toolkits.
For seven of the GRB alerts, our network was able to start the first observations less than one hour after the GRB trigger time. We also characterized the network efficiency to observe GRB afterglow given the resulting time delay and limiting magnitude, and to its light curve evolution based on the observation of GRB\, 220427A.
Abstract
On 2019 October 1, the IceCube Collaboration detected a muon track neutrino with a high probability of being of astrophysical origin, IC191001A. After a few hours, the tidal disruption event ...(TDE) AT2019dsg, observed by the Zwicky Transient Facility (ZTF), was indicated as the most likely counterpart of the IceCube track. More recently, the follow-up campaign of the IceCube alerts by ZTF suggested a second TDE, AT2019fdr, as a promising counterpart of another IceCube muon track candidate, IC200530A, detected on 2020 May 30. Here, these intriguing associations are followed-up by searching for neutrinos in the ANTARES detector from the directions of AT2019dsg and AT2019fdr using a time-integrated approach. As no significant evidence for space clustering is found in the ANTARES data, upper limits on the one-flavor neutrino flux and fluence are set.
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