Related Experiment Video
Updated: Jul 17, 2026
06:28
Visualization of Low-Level Gamma Radiation Sources Using a Low-Cost, High-Sensitivity, Omnidirectional Compton Camera
Published on: January 30, 2020
No supernovae detected in two long-duration gamma-ray bursts
D Watson1, J P U Fynbo, C C Thöne
1Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen Ø, Denmark. darach.watson@gmail.com
Summary
Some long-duration gamma-ray bursts (GRBs) lack supernova (SN) emission, challenging the standard collapsar model. This suggests a new type of massive star death event, distinct from typical core-collapse supernovae.
Area of Science:
- Astrophysics
- Cosmic explosions
- Gamma-ray astronomy
Background:
- Long-duration gamma-ray bursts (GRBs) are typically associated with core-collapse supernovae (SN) from massive stars, as per the collapsar model.
- Previous observations confirmed this association for several nearby GRBs.
Purpose of the Study:
- To investigate the nature of long-duration GRBs that do not exhibit associated SN emission.
- To determine if these GRBs originate from massive stars despite the absence of a detectable supernova.
Main Methods:
- Analysis of multi-band observations of early afterglows for GRBs 060505 and 060614.
- Spectroscopy of the host galaxies to assess properties and rule out dust obscuration.
- Localization of GRB 060505 within its host galaxy.
Main Results:
- No SN emission was detected for GRBs 060505 and 060614, even at sensitivities far below typical Type Ic SN.
- Observations excluded significant dust obscuration as a cause for the lack of SN.
- The GRBs originated in star-forming galaxies, with GRB 060505 located in a star-forming region.
Conclusions:
- The properties of the host galaxies and the GRB characteristics strongly imply a massive stellar origin.
- The absence of SN emission suggests a new phenomenological class of massive stellar death events.
Related Concept Videos
01:10Detection of Black Holes
Although black holes were theoretically postulated in the 1920s, they remained outside the domain of observational astronomy until the 1970s.
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
01:06Nuclear Overhauser Enhancement (NOE)
Irradiation of a spin-active nucleus causes an increase or decrease in the signal intensity of neighboring nuclei that are not necessarily chemically bonded or involved in J-coupling. This phenomenon, called the nuclear Overhauser enhancement (NOE), results from through-space interactions between the nuclear spins. The NOE effect decreases with increasing internuclear distance and is generally not observed beyond 4 angstroms. In NOE, dipole-dipole interactions between neighboring spin-active...
01:11Atomic Nuclei: Larmor Precession Frequency
The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) that causes the mass to 'wobble' around the gravitational field axis in a phenomenon called precession. Similarly, the magnetic moment (μ) of a spinning nucleus precesses due to an external magnetic field directed along the z-axis. The precession of the magnetic moment vector about the magnetic field is called Larmor precession, and the angular frequency...
01:30Atomic Emission Spectroscopy: Interference
In atomic emission spectroscopy (AES), high-temperature atomizers excite a broad range of elements and molecules that generate complex emissions from sources such as oxides, hydroxides, and flame combustion products in the flame or plasma. Several strategies can be employed to minimize spectral interferences caused by overlapping emission lines or bands. These include increasing instrument resolution, choosing alternative emission lines, optimally placing the detector in low-background regions,...
03:23Types of Radioactivity
The most common types of radioactivity are α decay, β decay, γ decay, neutron emission, and electron capture.
Alpha (α) decay is the emission of an α particle from the nucleus. For example, polonium-210 undergoes α decay:
Alpha (α) decay is the emission of an α particle from the nucleus. For example, polonium-210 undergoes α decay:
01:28Atomic Nuclei: Types of Nuclear Relaxation
Nuclear relaxation restores the equilibrium population imbalance and can occur via spin–lattice or spin–spin mechanisms, which are first-order exponential decay processes.
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers energy to a nearby...
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers energy to a nearby...