141 research outputs found
Searching for high-energy neutrinos from shock-interaction powered supernovae with the IceCube Neutrino Observatory
The sources of the astrophysical neutrino flux discovered by IceCube are for
the most part unresolved. Extragalactic core-collapse supernovae (CCSNe) have
been suggested as candidate multi-messenger sources. In interaction-powered
supernovae, a shock propagates in a dense circumstellar medium (CSM), producing
a bright optical emission and potentially accelerating particles to
relativistic energies. Shock interaction is believed to be the main energy
source for Type IIn supernovae (identified by narrow lines in the spectrum),
hydrogen-rich superluminous supernovae and a subset of hydrogen-poor
superluminous supernovae. Production of high-energy neutrinos is expected in
collisions between the accelerated protons in the shocks and the cold CSM
particles. We select a catalog of interaction-powered supernovae from the
Bright Transient Survey of the Zwicky Transient Facility. We exploit a novel
modeling effort that connects the time evolution of the optical emission to the
properties of the ejecta and the CSM, allowing us to set predictions of the
neutrino flux for each source. In this contribution, we describe a stacking
search for high-energy neutrinos from this population of CCSNe with the IceCube
Neutrino Observatory.Comment: Presented at the 38th International Cosmic Ray Conference (ICRC2023).
See arXiv:2307.13047 for all IceCube contributions. 8 pages, 4 figure
Searching for high-energy neutrinos from the most luminous supernovae with the IceCube Neutrino Observatory
The sources of the astrophysical neutrino flux discovered by IceCube remain for the most part unresolved. Extragalactic core-collapse supernovae (CCSNe) have been suggested as potentially able to produce high-energy neutrinos. In recent years, the Zwicky Transient Facility has discovered a population of exceptionally luminous supernovae, whose powering mechanisms have not yet been fully established. A fraction of these objects fall in the broader category of type IIn CCSNe, showing signs of interaction with a dense circumstellar medium. Theoretical models connect the supernova photometric properties to the dynamics of a shock-powered emission, predicting particle acceleration. In this contribution, we outline the plan for a search of high-energy neutrinos targeting the population of superluminous and type IIn supernovae with the IceCube Neutrino Observatory
Optically Informed Searches of High-Energy Neutrinos from Interaction-Powered Supernovae
The interaction between the ejecta of supernovae (SNe) of Type IIn and a
dense circumstellar medium (CSM) can efficiently generate thermal UV/optical
radiation and lead to the emission of neutrinos in the - TeV range.
We investigate the connection between the neutrino signal detectable at the
IceCube Neutrino Observatory and the electromagnetic signal observable by
optical wide-field, high-cadence surveys to outline the best strategy for
upcoming follow-up searches. We outline a semi-analytical model that connects
the optical lightcurve properties to the SN parameters and find that a large
peak luminosity (- erg) and an average
rise time (- days) are necessary for copious
neutrino emission. Nevertheless, the most promising and
are not sufficient to guarantee ideal conditions for neutrino
detection. Comparable optical properties can be obtained for SN configurations
that are not optimal for neutrino emission. Such ambiguous correspondence
between the optical lightcurve properties and the number of IceCube neutrino
events implies that relying on optical observations only, a range of expected
neutrino events should be considered (e.g. the expected number of neutrino
events can vary up to two orders of magnitude for some among the brightest SNe
IIn observed by the Zwicky Transient Facility up to now, SN 2020usa and SN
2020in). In addition, the peak in the high-energy neutrino curve should be
expected a few after the peak in the optical lightcurve. Our
findings highlight that it is crucial to infer the SN properties from
multi-wavelength observations rather than focusing on the optical band only to
enhance upcoming neutrino searches.Comment: 20 pages, including 14 figures and 3 appendice
An improved infrastructure for the IceCube realtime system
The IceCube realtime alert system has been operating since 2016. It provides
prompt alerts on high-energy neutrino events to the astroparticle physics
community. The localization regions for the incoming direction of neutrinos are
published through NASA's Gamma-ray Coordinate Network (GCN). The IceCube
realtime system consists of infrastructure dedicated to the selection of alert
events, the reconstruction of their topology and arrival direction, the
calculation of directional uncertainty contours and the distribution of the
event information through public alert networks. Using a message-based workflow
management system, a dedicated software (SkyDriver) provides a representational
state transfer (REST) interface to parallelized reconstruction algorithms. In
this contribution, we outline the improvements of the internal infrastructure
of the IceCube realtime system that aims to streamline the internal handling of
neutrino events, their distribution to the SkyDriver interface, the collection
of the reconstruction results as well as their conversion into human- and
machine-readable alerts to be publicly distributed through different alert
networks. An approach for the long-term storage and cataloging of alert events
according to findability, accessibility, interoperability and reusability
(FAIR) principles is outlined.Comment: Presented at the 38th International Cosmic Ray Conference (ICRC2023).
See arXiv:2307.13047 for all IceCube contributions. 8 pages, 3 figure
Neutrino follow-up with the Zwicky Transient Facility: Results from the first 24 campaigns
The Zwicky Transient Transient Facility (ZTF) performs a systematic neutrino
follow-up program, searching for optical counterparts to high-energy neutrinos
with dedicated Target-of-Opportunity (ToO) observations. Since first light in
March 2018, ZTF has taken prompt observations for 24 high-quality neutrino
alerts from the IceCube Neutrino Observatory, with a median latency of 12.2
hours from initial neutrino detection. From two of these campaigns, we have
already reported tidal disruption event (TDE) AT2019dsg and likely TDE
AT2019fdr as probable counterparts, suggesting that TDEs contribute >7.8% of
the astrophysical neutrino flux. We here present the full results of our
program through to December 2021. No additional candidate neutrino sources were
identified by our program, allowing us to place the first constraints on the
underlying optical luminosity function of astrophysical neutrino sources.
Transients with optical absolutes magnitudes brighter that -21 can contribute
no more than 87% of the total, while transients brighter than -22 can
contribute no more than 58% of the total, neglecting the effect of extinction.
These are the the first observational constraints on the neutrino emission of
bright populations such as superluminous supernovae. None of the neutrinos were
coincident with bright optical AGN flares comparable to that observed for TXS
0506+056/IC170922A, suggesting that most astrophysical neutrinos are not
produced during such optical flares. We highlight the outlook for
electromagnetic neutrino follow-up programs, including the expected potential
for the Rubin Observatory.Comment: To be submitted to MNRAS, comments welcome
Event reconstruction for KM3NeT/ORCA using convolutional neural networks
The KM3NeT research infrastructure is currently under construction at two
locations in the Mediterranean Sea. The KM3NeT/ORCA water-Cherenkov neutrino
detector off the French coast will instrument several megatons of seawater with
photosensors. Its main objective is the determination of the neutrino mass
ordering. This work aims at demonstrating the general applicability of deep
convolutional neural networks to neutrino telescopes, using simulated datasets
for the KM3NeT/ORCA detector as an example. To this end, the networks are
employed to achieve reconstruction and classification tasks that constitute an
alternative to the analysis pipeline presented for KM3NeT/ORCA in the KM3NeT
Letter of Intent. They are used to infer event reconstruction estimates for the
energy, the direction, and the interaction point of incident neutrinos. The
spatial distribution of Cherenkov light generated by charged particles induced
in neutrino interactions is classified as shower- or track-like, and the main
background processes associated with the detection of atmospheric neutrinos are
recognized. Performance comparisons to machine-learning classification and
maximum-likelihood reconstruction algorithms previously developed for
KM3NeT/ORCA are provided. It is shown that this application of deep
convolutional neural networks to simulated datasets for a large-volume neutrino
telescope yields competitive reconstruction results and performance
improvements with respect to classical approaches
Event reconstruction for KM3NeT/ORCA using convolutional neural networks
The KM3NeT research infrastructure is currently under construction at two locations in the Mediterranean Sea. The KM3NeT/ORCA water-Cherenkov neutrino de tector off the French coast will instrument several megatons of seawater with photosensors. Its main objective is the determination of the neutrino mass ordering. This work aims at demonstrating the general applicability of deep convolutional neural networks to neutrino telescopes, using simulated datasets for the KM3NeT/ORCA detector as an example. To this end, the networks are employed to achieve reconstruction and classification tasks that constitute an alternative to the analysis pipeline presented for KM3NeT/ORCA in the KM3NeT Letter of Intent. They are used to infer event reconstruction estimates for the energy, the direction, and the interaction point of incident neutrinos. The spatial distribution of Cherenkov light generated by charged particles induced in neutrino interactions is classified as shower-or track-like, and the main background processes associated with the detection of atmospheric neutrinos are
recognized. Performance comparisons to machine-learning classification and maximum-likelihood reconstruction algorithms previously developed for KM3NeT/ORCA are provided. It is shown that this application of deep convolutional neural networks to simulated datasets for a large-volume neutrino telescope yields competitive reconstruction results and performance
improvements with respect to classical approaches
Multi-messenger searches via IceCube’s high-energy neutrinos and gravitational-wave detections of LIGO/Virgo
We summarize initial results for high-energy neutrino counterpart searches coinciding with gravitational-wave events in LIGO/Virgo\u27s GWTC-2 catalog using IceCube\u27s neutrino triggers. We did not find any statistically significant high-energy neutrino counterpart and derived upper limits on the time-integrated neutrino emission on Earth as well as the isotropic equivalent energy emitted in high-energy neutrinos for each event
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