Multi-messenger astrophysics

The discovery of a new ultra-high-energy gamma-ray source, 1LHAASO J1857+0203u, by the Large High Altitude Air Shower Observatory (LHAASO) suggests the presence of a PeVatron, a cosmic accelerator capable of boosting particles to peta-electron volt energies. This source is particularly interesting because it is located in a region with complex multi-wavelength features, including the supernova rem...

The TAIGA-HiSCORE Cherenkov array, located in Siberia, is a unique instrument designed to study cosmic rays and gamma rays. However, scientists have realized that it can also be used to search for a variety of fascinating astronomical phenomena, including nanosecond optical transients . What are nanosecond optical transients? These are extremely short bursts of light that last for only a few nanos...

Kilonovae (KNe) are bright, rapidly fading astronomical events believed to be caused by the radioactive decay of heavy elements produced during the merger of neutron stars or a neutron star and a black hole. While there are several candidate KNe events observed in association with short gamma-ray bursts (GRBs), there is only one confirmed KN associated with a gravitational wave (GW) event, AT2017g...

In this episode, we explore the fascinating world of diffuse gamma rays emanating from the Galactic plane. A new study using the Large High Altitude Air Shower Observatory's Water Cherenkov Detector Array (LHAASO-WCDA) has provided unprecedented insights into these mysterious emissions. What are diffuse gamma rays? These high-energy photons are produced when cosmic rays, energetic particles that c...

Publication: arXiv:2411.06996 Acknowledements: Podcast prepared with Google/NotebookLM. Illustration credits: Y. Xing et al. (arXiv:2411.06996)

IACTs (Imaging Atmospheric Cherenkov Telescopes) are typically used for gamma-ray astronomy. Muons are produced in hadronic showers and IACTs can detect these muons, which are normally considered background noise. The information from these muons can be used to study cosmic ray showers. One way to study cosmic rays is by observing the muon lateral distribution , which is the muon density as a func...

Ultra-high-energy cosmic rays (UHECRs) are the most energetic particles ever detected, with energies exceeding 10^18 eV. Their origin remains a mystery, as their paths are deflected by magnetic fields in space, making it difficult to trace them back to their sources. Scientists use models of the Galactic magnetic field (GMF) to account for these deflections and try to pinpoint the sources of UHECR...

Swift's New Capability: Continuous Commanding A new capability of the Neil Gehrels Swift Observatory, called "continuous commanding", allows Swift to respond to targets of opportunity within 10 seconds. This capability allows Swift to receive commands in real-time because the spacecraft is now constantly in contact with the ground. This capability was developed to allow Swift to respond to early w...

The Pierre Auger Observatory, situated in Argentina, is designed to detect UHE cosmic rays. The observatory is also sensitive to UHE photons and has been used to search for photons from various sources. This study looked for coincidences between UHE photon events and a selection of GW events detected by the LIGO/Virgo observatories. No UHE photon events were observed in coincidence with any of the...

Astronomers discovered a new long-period (21-minute) radio transient called GPM J1839–10, with the Murchison Widefield Array (MWA). Follow-up observations were done using other telescopes, including the Australia Telescope Compact Array (ATCA), Parkes/Murriyang radio telescope, the Australian Square Kilometre Array Pathfinder (ASKAP), and MeerKAT. The pulses from GPM J1839–10 vary in brightness, l...

Microquasars, like V4641 Sgr, are binary star systems with a black hole that pulls material from a companion star. They are fascinating objects for astronomers because they can produce jets of relativistic particles. The High-Altitude Water Cherenkov (HAWC) Observatory observed TeV gamma-ray emissions from V4641 Sgr. These observations suggest that the microquasar is accelerating particles far fro...

Astronomers using LOFAR detected a short, coherent radio flash at 144 MHz, 76.6 minutes after observing a short gamma-ray burst (GRB) called GRB 201006A . The probability of finding an unrelated transient is less than 1 in a million and it is thus likely the radio counterpart to GRB 201006A. The discovery of this radio flash suggests that searches for similar emissions could be helpful for multi-m...

The paper examines the " Matthew Effect " in science, where more well-known scientists or institutions tend to receive a disproportionate amount of credit for discoveries, even in collaborative efforts. This effect extends to large research collaborations, as demonstrated by the case of the LIGO, Virgo, and KAGRA collaborations . While LIGO, Virgo, and KAGRA have been working together since 2007 a...

Ultra-high-energy cosmic rays (UHECRs) are a mystery. Scientists still don’t know where or how they are created. A new study combines three kinds of data measured at the Auger Observatory : the energy spectrum, shower maximum depth distributions, and arrival directions of UHECRs. Publication : A.A. Halim et al., "Constraining models for the origin of ultra-high-energy cosmic rays with a novel comb...

GRB 201216C , a long GRB, was observed by numerous instruments, including Swift-BAT, Fermi-GBM, and the MAGIC telescopes. MAGIC detected GRB 201216C at a redshift of z = 1.1 , making it the farthest known source detected at VHE gamma rays. Modeling of GRB 201216C's multiwavelength data, including the MAGIC observations, favors a scenario where the GRB jet is expanding into a wind-like medium shape...

This episode explores the search for Galactic PeVatrons, powerful cosmic accelerators that boost cosmic rays to PeV energies (1 PeV = 10^15 eV). The study, conducted by researchers using the HAWC gamma-ray observatory and the IceCube Neutrino Observatory, focuses on identifying neutrino emission from known gamma-ray sources. The study focused on 22 gamma-ray sources detected by HAWC . The research...

Millisecond pulsars (MSPs) are incredibly stable rotators and can be used as extremely precise clocks. Pulsar Timing Arrays (PTAs) monitor a collection of these pulsars to detect gravitational waves (GWs). GWs affect the arrival times of pulses from these pulsars, causing tiny, correlated fluctuations. There are four main PTAs: The European Pulsar Timing Array (EPTA) combines data from five major...

This paper proposes that  binary neutron star mergers  are the source of  ultrahigh energy cosmic rays (UHECRs) . The authors argue that these mergers produce jets with nearly universal maximum rigidities, explaining the observed narrow range of rigidities in UHECRs. The paper also explains how the rate of these mergers, the power of their jets, and the production of heavy nuclei like tellurium du...

SN 2023ixf provided the earliest ever detection of shock breakout from a supernova. The red supergiant progenitor star had a radius of about 440 solar radii. Early observations revealed that the light curves evolved very rapidly (timescales of 1-2 hours), appearing fainter and redder than models predicted . The study authors attribute this to an optically thick dust shell surrounding the star that...

Description : Tilepy is an open-source platform revolutionizing multi-messenger astrophysics by optimizing the scheduling of follow-up observations for events with large sky localization uncertainties, such as gravitational waves, gamma-ray bursts, and high-energy neutrinos. Main Points ● What is Tilepy? Tilepy is a Python package designed to efficiently schedule observations by correlating galaxy...

Episode Title: Unveiling the Secrets of the BOAT (GRB 221009A) Description: Explore the awe-inspiring power and scientific significance of GRB 221009A, the brightest gamma-ray burst ever recorded. Join us as we unpack the observations from multiple telescopes, including Fermi-LAT, LHAASO, and H.E.S.S., to understand the mechanisms behind this extraordinary event. Key Talking Points: Unprecedented...

Shownotes for a Podcast Episode: Unprecedented Energy in Gamma-Ray Bursts Topic: A New Era of Gamma-Ray Burst Astronomy Introduction: Gamma-ray bursts (GRBs) are brief, intense flashes of gamma-ray radiation originating from distant galaxies. They are the most powerful explosions known in the universe. These bursts occur in two distinct phases: the prompt emission, a short, bright burst of gamma r...

Astro-COLIBRI is a platform designed for real-time exploration of extreme astronomical events, facilitating multi-messenger astrophysics research. The platform offers a user-friendly interface and state-of-the-art architecture, enabling astronomers worldwide to identify and observe events across various timescales. Astro-COLIBRI has been used in several research projects and has been featured in v...