The Youngest Star Clusters in the Large Magellanic Cloud

Oct 13, 2025 by wbrum.org 6 views

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Today: 12papers

Precursor Activity Preceding Interacting Supernovae I: Bridging the Gap with SN 2022mop

Authors: S. J. Brennan, S. Bartmentloo, S. Schulze, K. W. Smith, R. Hirai, J. J. Eldridge, M. Fraser, H. F. Stevance, S. J. Smartt, S. Anand, A. Aryan, T.-W. Chen, K. K. Das, A. J. Drake, C. Fransson, A. Gangopadhyay, A. Gkini, W. V. Jacobson-Galán, A. Jerkstrand, J. Johansson, M. Nicholl, G. Pignata, N. Sarin, A. Singh, J. Sollerman, S. Srivastav, B.F.A. van Baal, K. C. Chambers, M. W. Coughlin, H. Gao, M. J. Graham, M. E. Huber, C.-C. Lin, T. B. Lowe, E. A. Magnier, F. J. Masci, J. Purdum, A. Rest, B. Rusholme, R. Smith, I. A. Smith, J. W. Tweddle, R.J. Wainscoat, T. de Boer
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
Arxiv link: https://arxiv.org/abs/2503.08768
Pdf link: https://arxiv.org/pdf/2503.08768
Abstract Over the past two decades, an increasing number of transients have shown luminous activity at their explosion sites weeks to years before an interacting supernova (SN) is observed. For some objects, this pre-SN activity is typically linked to large-scale mass-loss events preceding core collapse, yet its triggering mechanism and the underlying explosion process remain uncertain. We present SN 2022mop, which was initially observed in August 2022, exhibiting nebular emission, including [O I], Mg I], and [Ca II], resembling the late-time (~200 days post-explosion) spectrum of a stripped-envelope SN (SESN) from a progenitor with M[ZAMS] < 18 Msun. SN 2022mop shows strong (~ 1 mag) repeating undulations in its light curve, suggesting late-time interaction. In mid-2024, the transient re-brightened for several months before a Type IIn SN (r[peak] = -18.2 mag) was observed in December 2024, closely resembling the evolution of SN 2009ip. By triangulating both transients using Pan-STARRS images, we determine that both transients are coincident within approximately 3 parsecs. Given the environment, the chance alignment of two isolated SNe is unlikely. We propose a merger-burst scenario: a compact object formed in 2022, is kicked into an eccentric orbit, interacts with its hydrogen-rich companion over subsequent months, and ultimately merges, triggering a Type IIn SN-like transient.

Echoes of Self-Interacting Dark Matter from Binary Black Hole Mergers

Authors: Amitayus Banik, Jeong Han Kim, Jun Seung Pi, Yuhsin Tsai
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
Arxiv link: https://arxiv.org/abs/2503.08787
Pdf link: https://arxiv.org/pdf/2503.08787
Abstract Dark matter (DM) environments around black holes (BHs) can influence their mergers through dynamical friction, causing gravitational wave (GW) dephasing during the inspiral phase. While this effect is well studied for collisionless dark matter (CDM), it remains unexplored for self-interacting dark matter (SIDM) due to the typically low DM density in SIDM halo cores. In this work, we show that SIDM models with a massive force mediator can support dense enough DM spikes, significantly affecting BH mergers and producing a distinct GW dephasing. Using ${N}$ -body simulations, we analyze GW dephasing in binary BH inspirals within CDM and SIDM spikes. By tracking the binary's motion in different SIDM environments, we show that the Laser Interferometer Space Antenna (LISA) can distinguish DM profiles shaped by varying DM interaction strengths, revealing detailed properties of SIDM.

Multi-Phase Shock Cooling Emission in Ultra-Stripped Supernovae

Authors: Annastasia Haynie, Samantha C. Wu, Anthony L. Piro, Jim Fuller
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
Arxiv link: https://arxiv.org/abs/2503.08790
Pdf link: https://arxiv.org/pdf/2503.08790
Abstract Ultra-stripped and Type Ibn supernovae (USSNe and SNe Ibn, respectively) are fast-evolving, hydrogen-poor transients that often show signs of interaction with dense circumstellar material (CSM). Wu & Fuller (2022) identify a mass range for helium-core stars in which they expand significantly during core oxygen/neon burning, resulting in extreme late-stage mass loss in tight binaries ( $P\sim1-100\,{\rm days}$ ). Here we explore the resulting light curves from a subset of models from Wu & Fuller (2022) and find that in some cases they can exhibit two phases of shock cooling emission (SCE). The first SCE is attributed to the circumbinary material, and the second SCE is from the extended helium-burning envelope of the exploding star. Since SCE luminosity is roughly proportional to the initial radius of the emitting material, events that exhibit both phases of SCE provide the exciting opportunity of measuring both the extent of the CSM and the radius of the exploding star.

The Youngest Star Clusters in the Large Magellanic Cloud

Authors: Ricardo Chávez, Rosa Amelia González-Lópezlira, Gustavo Bruzual
Subjects: Astrophysics of Galaxies (astro-ph.GA)
Arxiv link: https://arxiv.org/abs/2503.08888
Pdf link: https://arxiv.org/pdf/2503.08888
Abstract This study presents a comprehensive analysis of the youngest stellar clusters in the Large Magellanic Cloud (LMC), utilising a multi-wavelength approach. We analyse data spanning from infrared to ultraviolet wavelengths, with the goal of enhancing our understanding of these clusters' physical properties, such as age, mass, and size. Our methodology includes a novel cluster detection procedure; it employs machine learning techniques for the accurate identification of these young clusters. The Markov Chain Monte Carlo analysis, using the Automated Stellar Cluster Analysis tool, plays a crucial role in deriving the clusters' key physical parameters. Our findings provide significant insights into the early stages of stellar and galactic evolution, particularly in dwarf galaxy environments, and contribute to the broader understanding of star formation and cluster evolution.

FAST Discovery of A Gas-rich and Ultra-faint Dwarf Galaxy: KK153

Authors: Jin-Long Xu, Ming Zhu, Nai-Ping Yu, Chuan-Peng Zhang, Xiao-Lan Liu, Mei Ai, Peng Jiang
Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Arxiv link: https://arxiv.org/abs/2503.08999
Pdf link: https://arxiv.org/pdf/2503.08999
Abstract Based on a high-sensitivity HI survey using the Five-hundred-meter Aperture Spherical radio Telescope (FAST), we identified an isolated HI cloud with a system velocity of ~127.0 km/s, which is associated with an optical galaxy KK153 in space. The HI gas of KK153 shows a typical disk-galaxy structure. Using the Baryonic Tully-Fisher relation, we obtained that the distance to KK153 is 2.0_{-0.8}^{+1.7} Mpc. Adopting such distance, we derived a stellar mass of 4.1_{-2.6}^{+10.0}*10{5} Msun and a neutral gas fraction of 0.63, implying that KK153 is a gas-rich ultra-faint dwarf (UFD) galaxy in the Local Group or its outskirts. KK153 shows a cool (~200 K) and warm (~7400 K) two-phase neutral medium. The g-r color distribution of KK153 suggests that new stars are mostly forming in its inner disk.

Progenitor Dependence of Neutrino-driven Supernova Explosions with the Aid of Heavy Axion-like Particles

Authors: Tsurugi Takata, Kanji Mori, Ko Nakamura, Kei Kotake
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
Arxiv link: https://arxiv.org/abs/2503.09005
Pdf link: https://arxiv.org/pdf/2503

In our previous article, we showcased 12 new papers on star formation and molecular clouds. In this Q&A article, we'll delve deeper into the research and answer some of the most pressing questions in the field.

Q: What is the significance of the merger-burst scenario proposed in the paper "Precursor Activity Preceding Interacting Supernovae I: Bridging the Gap with SN 2022mop"?

A: The merger-burst scenario proposes that a compact object formed in 2022 is kicked into an eccentric orbit, interacts with its hydrogen-rich companion over subsequent months, and ultimately merges, triggering a Type IIn SN-like transient. This scenario has significant implications for our understanding of supernovae and the role of mergers in shaping the evolution of stars.

Q: How does the self-interacting dark matter (SIDM) model affect the mergers of binary black holes?

A: The SIDM model can support dense enough DM spikes, significantly affecting BH mergers and producing a distinct GW dephasing. This has important implications for the detection of gravitational waves and the study of dark matter.

Q: What is the significance of the two phases of shock cooling emission (SCE) observed in ultra-stripped supernovae?

A: The two phases of SCE provide the exciting opportunity of measuring both the extent of the CSM and the radius of the exploding star. This has significant implications for our understanding of the explosion mechanism and the properties of the progenitor star.

Q: What is the FAST discovery of a gas-rich and ultra-faint dwarf galaxy: KK153?

A: The FAST discovery of KK153 is a significant finding, as it provides insights into the early stages of stellar and galactic evolution, particularly in dwarf galaxy environments. The galaxy's gas-rich nature and ultra-faint dwarf classification make it an interesting target for further study.

Q: How does the progenitor dependence of neutrino-driven supernova explosions with the aid of heavy axion-like particles affect our understanding of supernovae?

A: The inclusion of heavy axion-like particles in the progenitor dependence of neutrino-driven supernova explosions has significant implications for our understanding of supernovae. The particles can affect the explosion mechanism and the properties of the progenitor star.

Q: What are the implications of the tiny-scale properties within the interstellar medium towards PSR J1644$-$4559?

A: The study of the tiny-scale properties within the interstellar medium towards PSR J1644$-$4559 provides insights into the dynamics of the interstellar medium and the role of turbulence in shaping the properties of the medium.

Q: How does the magnetic field properties of the SNR HB 9 affect our understanding of supernovae?

A: The study of the magnetic field properties of the SNR HB 9 provides insights into the magnetic field structure and the role of magnetic fields in shaping the properties of supernovae.

Q: What are the implications of treating Earth as an exoplanet and studying the effects of clouds on the spectrum?

A: The study of the effects of clouds on the spectrum of Earth as an exoplanet provides insights into the properties of clouds and their impact on the detectability of atmospheric constituents.

Q: How does the tomography of the Ophiuchus Molecular Cloud with velocity features in C $_2$ H $N=1-0$ spectra affect our understanding of star formation?

A: The study of the tomography of the Ophiuchus Molecular Cloud with velocity features in C $_2$ H $N=1-0$ spectra provides insights into the properties of the cloud and the role of velocity features in shaping the properties of star-forming regions.

Q: What are the implications of the properties of contracting massive protostellar cores?

A: The study of the properties of contracting massive protostellar cores provides insights into the properties of the cores and the role of contraction in shaping the evolution of stars.

We hope this Q&A article has provided a deeper understanding of the latest research in star formation and molecular clouds. If you have any further questions, please don't hesitate to ask!