The Formation of Long-Duration Gamma-Ray Bursts and Broad-Lined Supernovae from Close Binary Stars with Black Hole Engines

Основні поняття

Close binary star systems with black hole accretion disk engines offer a compelling explanation for the formation of long-duration gamma-ray bursts (lGRBs), low-luminosity GRBs, ultra-long GRBs, and broad-lined Type Ic supernovae (Ic-BL SNe).

Анотація

• Bibliographic Information: Fryer, C. L., Burns, E., Ho, A. Y. Q., Corsi, A., Lien, A. Y., Perley, D. A., ... & Villar, V. A. (2024). Explaining Non-Merger Gamma-Ray Bursts and Broad-Lined Supernovae with Close Binary Progenitors with Black Hole Central Engine. The Astrophysical Journal.

• Research Objective: This research paper investigates the viability of close binary star systems as progenitors for long-duration gamma-ray bursts (lGRBs) and their associated supernovae, particularly broad-lined Type Ic supernovae (Ic-BL SNe). The authors aim to determine if this scenario, combined with different lGRB engine models, can explain the observed properties of these energetic transients.

• Methodology: The authors employ a combination of stellar evolution models and accretion disk physics to simulate the collapse of massive stars in close binary systems. They consider different angular momentum transport mechanisms within the stars and explore the resulting spin rates of the compact remnants (neutron stars or black holes). The team then investigates the energy output and observational signatures of both magnetar and black hole accretion disk (BHAD) engine models.

• Key Findings: The study finds that close binary progenitors, particularly those involving carbon-oxygen (CO) stars, can lead to the formation of rapidly rotating compact remnants. These systems can potentially power lGRBs, low-luminosity GRBs, and ultra-long GRBs through the action of BHAD engines. The authors demonstrate that the BHAD engine model, combined with the tight-binary scenario, can reproduce a wide range of observed GRB durations and energetics. Additionally, the model predicts the ejection of material with specific nucleosynthetic yields and the potential for shock interactions with circumstellar material, both of which can be observed in the associated supernovae.

• Main Conclusions: The research concludes that the close binary progenitor scenario, coupled with BHAD engines, provides a consistent explanation for the origin of various lGRB subclasses and their associated Ic-BL SNe. The authors highlight the importance of future observations, particularly in the areas of gravitational wave astronomy and late-time supernova light curves, to further constrain the properties of these systems and refine our understanding of lGRB formation.

• Significance: This study significantly contributes to the field of astrophysics by providing a unified model for the formation of lGRBs and Ic-BL SNe. It highlights the crucial role of binary interactions in the evolution of massive stars and their explosive deaths. The findings have implications for our understanding of stellar nucleosynthesis, the dynamics of accretion disks around black holes, and the production of gravitational wave signals.

• Limitations and Future Research: The authors acknowledge that the complexities of stellar evolution and accretion disk physics introduce uncertainties into their models. They emphasize the need for more sophisticated simulations, incorporating detailed treatments of magnetic fields, neutrino transport, and general relativistic effects, to improve the accuracy of their predictions. Future observations with next-generation telescopes and gravitational wave detectors will be crucial for testing the model's predictions and further constraining the properties of lGRB progenitors.

Статистика

Less than 1 in 1000 stellar collapses produce lGRBs.
Roughly 1 in 10 stellar collapses create black holes.
Magnetar engines have a maximum energy limit of approximately 7 × 10^52 erg due to neutron star instabilities.
Accretion rates above 0.5-1 M⊙s−1 are required to achieve significant deleptonization in BHAD systems.
The 56Ni yield, a key power source for supernovae, can vary by an order of magnitude depending on the accretion disk radius.

Цитати

Ключові висновки, отримані з

Explaining Non-Merger Gamma-Ray Bursts and Broad-Lined Supernovae with Close Binary Progenitors with Black Hole Central Engine

by Christopher ... о arxiv.org 10-15-2024

https://arxiv.org/pdf/2410.10378.pdf

Глибші Запити

How might the interaction of the GRB jet with the companion star in a close binary system affect the observed properties of the GRB and its afterglow?

The interaction of a GRB jet with a companion star in a close binary system can significantly impact the observed properties of both the GRB and its afterglow. Here's how:
Impact on GRB:

Jet Break Out: The companion star can obstruct the GRB jet, delaying or even preventing its breakout. This can lead to:

Shorter GRB durations: If the jet is choked before it can fully escape, we might observe shorter GRBs than expected from a single-star progenitor.
Off-axis GRBs: The jet might be forced to break out at an angle relative to our line of sight, resulting in a fainter, "off-axis" GRB.

Jet Shaping: The companion star's gravitational pull can influence the jet's shape and propagation direction. This can lead to:

Asymmetric jets: Instead of a symmetrical cone, the jet might become distorted, affecting the observed light curve and polarization.

Precursor Emission: The jet's interaction with the companion star's outer layers can produce precursor emission before the main GRB pulse. This emission could be observed in:

X-rays or optical wavelengths: Depending on the interaction mechanism, we might see a distinct X-ray or optical flash preceding the gamma-ray emission.
Impact on Afterglow:

Early Afterglow: The presence of the companion star can modify the density profile of the surrounding medium, affecting the early afterglow. This can lead to:

Brighter afterglows: If the jet interacts with denser material stripped from the companion, the early afterglow could be brighter than expected.
Unusual light curves: The interaction can create complex density structures, resulting in deviations from the standard afterglow light curve models.

Late Afterglow: The companion star itself can become a source of late-time emission as it accretes material from the GRB or the disrupted stellar material. This can lead to:

Long-lasting afterglows: The companion's emission could power a longer-lasting afterglow than expected from the GRB jet alone.
Variable afterglows: The accretion process onto the companion could be unsteady, leading to variability in the late-time afterglow.
Observational Signatures:
Observing these signatures can provide strong evidence for a binary progenitor in GRBs:

Early-time observations: Crucial for capturing precursor emission and the initial interaction of the jet with the companion star.
Multi-wavelength observations: Essential for studying the afterglow evolution and distinguishing between emission from the jet and the companion star.
Spectroscopic observations: Can reveal the composition of the material ejected during the interaction and provide insights into the companion star's properties.

Could alternative progenitor scenarios, such as the collapse of rapidly rotating massive stars in isolation, also explain the observed diversity of lGRBs and their supernovae?

While the collapse of rapidly rotating massive stars in isolation (the collapsar model) remains a leading contender for explaining lGRBs and their supernovae, it faces challenges in accounting for the full diversity of observed properties.
Here's a breakdown of the strengths and weaknesses of the single-star collapsar model:
Strengths:

Natural explanation for long durations: The collapse of a massive star provides a long-lived engine capable of powering the extended durations observed in lGRBs.
Connection to supernovae: The model inherently links lGRBs with the deaths of massive stars, naturally explaining the association with Type Ic-BL supernovae.
Weaknesses:

Achieving sufficient rotation: Single stars struggle to maintain the extremely high rotation rates needed to form a collapsar. Stellar winds can spin down massive stars over their lifetimes, making it difficult to retain enough angular momentum in the core.
Diversity of engine powers: The collapsar model struggles to explain the wide range of observed GRB energies and durations, from low-luminosity GRBs to ultra-long GRBs.
Lack of observed progenitors: Despite numerous searches, direct observations of lGRB progenitors have been elusive, casting some doubt on the single-star scenario.
Alternative Progenitor Scenarios:
While the single-star collapsar model faces challenges, it's not entirely ruled out. Modifications to the standard model, such as:

Chemically homogeneous evolution: Stars with enhanced mixing could potentially retain more angular momentum, leading to faster-rotating cores.
Binary interactions: Interactions with a companion star, even if not as tightly bound as in the tidal spin-up scenario, could provide the necessary angular momentum boost.
However, these modifications often introduce additional complexities and uncertainties.
Conclusion:
The single-star collapsar model, while appealing, struggles to fully explain the observed diversity of lGRBs and their supernovae. Close binary progenitors, with their potential for tidal spin-up and diverse evolutionary pathways, offer a compelling alternative that can potentially account for a wider range of observed properties. Further observations, particularly of lGRB progenitors and their environments, are crucial for definitively determining the dominant formation channel of these powerful explosions.

What are the implications of this research for our understanding of the cosmic evolution of heavy elements and the role of lGRBs in enriching the early universe?

This research on lGRB progenitors and their connection to Ic-BL supernovae has profound implications for our understanding of how heavy elements are created and distributed throughout the cosmos, particularly in the early universe:
Heavy Element Production Sites:

Constraining r-process contributions: The research suggests that lGRBs, particularly those arising from the BHAD engine in close binary systems, might not be significant producers of r-process elements. The accretion rates onto the black hole, while high, might not be sufficient to consistently achieve the necessary neutron-rich conditions for substantial r-process nucleosynthesis.
Focus on disk wind nucleosynthesis: The study highlights the importance of disk winds in lGRB events as potential sites for synthesizing iron-peak elements and lighter heavy elements. The amount and composition of these elements ejected in the wind are sensitive to the properties of the accretion disk, providing a link between the GRB engine and the observed chemical abundances.
Early Universe Enrichment:

Metallicity dependence of progenitors: The research suggests that the specific type of lGRB progenitor (e.g., tight CO-star binaries) might be sensitive to the metallicity of the host environment. This implies that the contribution of lGRBs to early universe enrichment could be highly dependent on the cosmic metallicity evolution.
Alternative enrichment channels: If lGRBs are not the primary sources of r-process elements, other potential candidates, such as neutron star mergers, gain prominence. Understanding the relative contributions of these different explosive events is crucial for modeling the chemical evolution of galaxies and the early universe.
Observational Tests and Future Directions:

Spectroscopic studies of lGRB afterglows: Detailed analysis of the absorption and emission lines in lGRB afterglows can reveal the chemical fingerprints of the explosion and its progenitor, providing clues about the elements synthesized.
Connecting lGRBs to their host galaxies: Studying the properties of lGRB host galaxies, such as their star formation rates, metallicities, and ages, can provide insights into the environments where these events occur and their connection to cosmic evolution.
Overall Impact:
This research underscores the complex interplay between stellar evolution, binary interactions, and explosive events in shaping the chemical makeup of the universe. By refining our understanding of lGRB progenitors and their nucleosynthetic capabilities, we gain a clearer picture of how heavy elements are forged and dispersed, ultimately influencing the formation of planets, stars, and life itself.