Article
Astronomy & Astrophysics
Kirsten L. Larson, Janice C. Lee, David A. Thilker, Bradley C. Whitmore, Sinan Deger, James Lilly, Rupali Chandar, Daniel A. Dale, Frank Bigiel, Kathryn Grasha, Brent Groves, Stephen Hannon, Ralf S. Klessen, Kathryn Kreckel, J. M. Diederik Kruijssen, Adam K. Leroy, Hsi-An Pan, Erik Rosolowsky, Eva Schinnerer, Andreas Schruba, Elizabeth J. Watkins, Thomas G. Williams
Summary: We developed a method to identify stellar associations using HST NUV-U-B-V-I imaging and applied it to two galaxies in the PHANGS-HST survey. Our algorithm successfully characterizes the properties of the associations and provides a more complete census of recent star formation activity. Younger associations correlate closely with H ii regions, while older associations show an anti-correlation with H α emission.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
C. Schimd, M. Sereno
Summary: A classification scheme based on shapefinders deduced from the Minkowski functionals is examined to fully account for the morphological diversity of galaxy clusters, including relaxed and merging clusters, clusters fed by filamentary structures, and cluster-pair bridges.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Yihao Zhou, Haiguang Xu, Zhenghao Zhu, Yuanyuan Zhao, Shida Fan, Chenxi Shan, Yongkai Zhu, Lei Hao, Li Ji, Zhongli Zhang, Xianzhong Zheng
Summary: Radio relics, large synchrotron sources in galaxy clusters, can be explained by models incorporating fossil relativistic electrons. Results show that these fossil electrons significantly contribute to the radio emission and can generate radiation much brighter than thermal electrons. The study also predicts the presence of relics in a certain percentage of clusters and the potential foreground contamination in future experiments.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Michael Y. Grudic, J. M. Diederik Kruijssen, Claude-Andre Faucher-Giguere, Philip F. Hopkins, Xiangcheng Ma, Eliot Quataert, Michael Boylan-Kolchin
Summary: In our model, the ratio of the strength of gravity to stellar feedback is the key parameter setting the masses of star clusters, and direct stellar radiation (photon momentum and photoionization) is the most important feedback channel on GMC scales.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Fabian Scheuermann, Kathryn Kreckel, Ashley T. Barnes, Francesco Belfiore, Brent Groves, Stephen Hannon, Janice C. Lee, Rebecca Minsley, Erik Rosolowsky, Frank Bigiel, Guillermo A. Blanc, Mederic Boquien, Daniel A. Dale, Sinan Deger, Oleg Egorov, Eric Emsellem, Simon C. O. Glover, Kathryn Grasha, Hamid Hassani, Sarah M. R. Jeffreson, Ralf S. Klessen, J. M. Diederik Kruijssen, Kirsten L. Larson, Adam K. Leroy, Laura A. Lopez, Hsi-An Pan, Patricia Sanchez-Blazquez, Francesco Santoro, Eva Schinnerer, David A. Thilker, Bradley C. Whitmore, Elizabeth J. Watkins, Thomas G. Williams
Summary: Connecting the gas in H II regions to the underlying ionizing radiation source helps us understand stellar feedback and the evolution of H II regions. Using PHANGS-MUSE, we detect and measure physical properties of nearly 24,000 H II regions across 19 galaxies. By analyzing associations with ionizing sources, we find correlations between association ages and various properties, suggesting an evolutionary sequence. We also observe correlations with local metallicity variations, indicating preferential star formation in metal-rich areas.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
C. L. Dobbs, T. J. R. Bending, A. R. Pettitt, A. S. M. Buckner, M. R. Bate
Summary: This article presents simulations of cluster formation and evolution in spiral arms. The inclusion of photoionizing feedback is found to increase the radii of clusters, while supernovae have little impact. In high-density, high gas mass simulations, star formation is less affected by feedback, and in the lowest gas density simulation, clusters are completely different from the case without feedback. The formation of associations, rather than clusters, is favored by low densities and stronger initial dynamics.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Dylan Britt, Ben Johanson, Logan Wood, M. Coleman Miller, Erez Michaely
Summary: Researchers explore the Lidov-Kozai-induced black hole mergers in open clusters and find a high merger rate density in the local Universe, with a significant proportion of mergers occurring during the cluster phase. This suggests that a substantial fraction of mergers from hierarchical triples occur within star-forming regions in spiral galaxies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Uddipan Banik, Frank C. van den Bosch
Summary: The study focuses on impulsive encounters between astrophysical objects, finding that the distant tide approximation method often overpredicts the energy change caused by impulses when the impact parameter is small, and is not suitable for the most interesting close encounters. To address these issues, a comprehensive, non-perturbative treatment of impulsive encounters is proposed, which is valid for any impact parameter and not hampered by divergence issues.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
A. N. Baushev
Summary: Our study reveals that the central density of voids is solely determined by the amplitude of the initial perturbation. N-body simulations may somewhat overestimate the emptiness of voids, and the density profile in the void center is expected to be very flat. The presence of dark energy is shown to reduce the underdensity of voids.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Fangfang Song, Ali Esamdin, Qingshun Hu, Mengfan Zhang
Summary: Based on Gaia database, researchers have discovered new binary open clusters and identified the truly binary ones. The results suggest that these truly binary open clusters are usually composed of young open clusters.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Daria Zakharova, Benedetta Vulcani, Gabriella De Lucia, Lizhi Xie, Michaela Hirschmann, Fabio Fontanot
Summary: This study investigates the properties of filaments and compares the methods of extracting filaments using dark matter distribution and model galaxy distribution. The results show that filaments extracted using different tracers are generally consistent but never coincide completely. Additionally, the number of filaments identified using galaxy distribution in massive clusters is typically underestimated.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Huanbin Chi, Feng Wang, Zhongmu Li
Summary: In this study, conventional HDBSCAN was extended with high-precision Gaia EDR3 data and modern machine-learning methods to search for new open clusters (OCs) in the Milky Way. A total of 83 new OCs were reported after cross-match and visual inspection, and the main parameters of the star clusters were estimated. This study significantly increases the sample size and physical parameters of OCs in the catalog, revealing the incompleteness of the OCs census across our Galaxy.
RESEARCH IN ASTRONOMY AND ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
D. Rosselli, F. Marulli, A. Veropalumbo, A. Cimatti, L. Moscardini
Summary: By analyzing the spectroscopic galaxy and galaxy cluster samples from the Sloan Digital Sky Survey, we derived new constraints on gravity theory. We detected the gravitational redshift effect in the velocity distribution of cluster member galaxies and compared it with the predictions of three different gravity theories. Our results are consistent with general relativity and the DGP model, but marginally disagree with the predictions of the f(R) model.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Efrain Gatuzz, J. S. Sanders, K. Dennerl, C. Pinto, A. C. Fabian, T. Tamura, S. A. Walker, J. ZuHone
Summary: In this study, the velocity structure of the Virgo cluster was analyzed in detail using XMM-Newton observations. The presence of high velocity structures, velocity gradient distribution, and possible effects of AGN outflows and gas sloshing were revealed in the complex velocity field of the cluster.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Juhi Tiwari, Kulinder Pal Singh
Summary: This study presents a detailed X-ray analysis of the central subcluster of the nearby Hercules cluster A2151C, revealing a bimodal structure with a bright hot gas clump towards the west and a fainter, cooler clump towards the east. This research identifies distinct characteristics of the subclusters and suggests the presence of a cool core in A2151C(B).
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)