Article
Astronomy & Astrophysics
Katja Fahrion, Teodora-Elena Bulichi, Michael Hilker, Ryan Leaman, Mariya Lyubenova, Oliver Muller, Nadine Neumayer, Francesca Pinna, Marina Rejkuba, Glenn van de Ven
Summary: Nuclear star clusters (NSCs) formation depends on the mass of the galaxies. Low-mass NSCs predominantly form from the merger of globular clusters (GCs) in dwarf galaxies, while high-mass NSCs in massive galaxies assemble through central enriched star formation. Spectral analysis of nine nucleated late-type dwarf galaxies shows that NSCs in low-mass galaxies mainly grow through the inspiral of GCs, while central star formation can contribute to NSC growth in more massive galaxies.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Robin Herlan, Alessandra Mastrobuono-Battisti, Nadine Neumayer
Summary: Observations show that M54, the nuclear star cluster of the Sgr dSph galaxy, matches a decayed globular cluster (GC) in a dark matter (DM) halo with a density profile proportional to r(-gamma) and gamma <= 1, based on its rotational signal and flattening. Steeper density profiles result in highly rotating and more flattened nuclear star clusters (NSCs) that do not match the properties of M54.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Jing Chen, Zhongmu Li, Su Zhang, Yangyang Deng, Wenchang Zhao
Summary: This paper investigates the extended main-sequence turnoffs (eMSTOs) and stellar populations of three clusters with different ages using Gaia Data Release 2 (DR2) data in detail. The colour-magnitude diagrams (CMDs) of three Galactic clusters show broad main sequences, eMSTOs, blue stragglers, and red giant clumps. The effects of age spread, binaries, and rotating stars on the morphology of the entire CMD are explored, with particular emphasis on the effects of binary stars and rotating stars on eMSTOs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Alan H. Su, Heikki Salo, Joachim Janz, Aku Venhola, Reynier F. Peletier
Summary: This study investigates the relations between nuclear star clusters and their host galaxies and compares the structural properties of nucleated and non-nucleated galaxies. The results show that the properties of nuclear star clusters differ based on the host galaxy's stellar mass, and the environment plays a significant role in the nucleation of galaxies.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
K. Fahrion, M. Lyubenova, G. van de Ven, M. Hilker, R. Leaman, J. Falcon-Barroso, A. Bittner, L. Coccato, E. M. Corsini, D. A. Gadotti, E. Iodice, R. M. McDermid, I. Martin-Navarro, F. Pinna, A. Poci, M. Sarzi, P. T. de Zeeuw, L. Zhu
Summary: Nuclear star clusters (NSCs) are the densest stellar systems in the Universe and are thought to form via mergers of star clusters or in situ star formation at galaxy centers. Research shows that NSCs in low-mass galaxies are more metal-poor than their hosts, while NSCs in massive galaxies exhibit diverse star formation histories. There is a clear transition in the dominant formation channel of NSCs with both galaxy and NSC mass.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
F. Rico-Villas, E. Gonzalez-Alfonso, J. Martin-Pintado, V. M. Rivilla, S. Martin
Summary: This study examines the thermal structure and kinematics of the proto-super star cluster 13 in NGC 253 using high resolution ALMA observations. The results reveal a Super Hot Core and provide insights into its origin and properties.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Natalia Lahen, Thorsten Naab, Guinevere Kauffmann
Summary: In this study, a photometric analysis of star and star cluster formation in a dwarf galaxy starburst is presented using a high-resolution simulation. The results show that different observational methods have varying levels of accuracy in tracing star formation during different phases, and aperture photometry analysis can lead to deviations in mass function and cluster formation efficiency.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
M. Mastropietro, S. De Rijcke, R. F. Peletier
Summary: This study investigates the formation and morphology of the arrow-shaped dwarf irregular galaxy NGC 1427A in the Fornax Cluster, using simulations to show similar tail structures. The analysis provides insights into the galaxy's position and velocity in the cluster without the need for interaction with nearby galaxies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Melina Poulain, Francine R. Marleau, Rebecca Habas, Pierre-Alain Duc, Ruben Sanchez-Janssen, Patrick R. Durrell, Sanjaya Paudel, Syeda Lammim Ahad, Abhishek Chougule, Oliver Muller, Sungsoon Lim, Michal Bilek, Jeremy Fensch
Summary: The study reveals that dwarf galaxies in low to moderate density environments exhibit similar structural and color properties to cluster dwarf galaxies, while dwarf nuclei are mainly found in massive, bright, and round dwarfs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Lijie Liu, Martin Bureau, Guang-Xing Li, Timothy A. Davis, Dieu D. Nguyen, Fu-Heng Liang, Woorak Choi, Mark R. Smith, Satoru Iguchi
Summary: In this study, we investigate the molecular structures in the dwarf galaxy NGC 404 using high-resolution observations. We find two distinct regions: a gravitationally stable central region and a gravitationally unstable molecular ring. The central region exhibits a steeper size-linewidth relation and larger virial parameters, suggesting more turbulent gas dynamics. In contrast, the molecular ring shows a shallower mass-size relation and larger virial parameters for clumps compared to clouds, indicating different physical mechanisms regulating density structures and dynamics. We propose a collision model to explain the results in the molecular ring, showing that clump-clump collisions driven by gravitational instabilities and galactic shear play a significant role in regulating clump properties and gas turbulence.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
M. Ozdogan Ela, A. Akyuz, N. Aksaker, S. Avdan, I. Akkaya Oralhan, A. Vinokurov, S. Allak, Y. Solovyeva, K. Atapin, D. Bizyaev
Summary: The study uses archival data from the Hubble Space Telescope to search for optical candidates of ultraluminous X-ray sources in two dwarf galaxies, confirming associations with young star groups and HII complexes. The X-ray spectral data suggest that the sources are in luminous hard states, consistent with long-term observations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Jordan A. Turner, Daniel A. Dale, Janice C. Lee, Mederic Boquien, Rupali Chandar, Sinan Deger, Kirsten L. Larson, Angus Mok, David A. Thilker, Leonardo Ubeda, Bradley C. Whitmore, Francesco Belfiore, Frank Bigiel, Guillermo A. Blanc, Eric Emsellem, Kathryn Grasha, Brent Groves, Ralf S. Klessen, Kathryn Kreckel, J. M. Diederik Kruijssen, Adam K. Leroy, Erik Rosolowsky, Patricia Sanchez-Blazquez, Eva Schinnerer, Andreas Schruba, Schuyler D. Van Dyk, Thomas G. Williams
Summary: The sensitivity and angular resolution of photometric surveys conducted by the Hubble Space Telescope allow for the study of individual star clusters in galaxies up to a few tens of megaparsecs away. By fitting the spectral energy distributions of star clusters using the cigale package, researchers can derive ages, stellar masses, and reddenings. Analysis of star clusters in NGC 3351 revealed that clusters in the inner star-forming ring are young and massive, while clusters in the stellar bulge are older.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
David A. Thilker, Bradley C. Whitmore, Janice C. Lee, Sinan Deger, Rupali Chandar, Kirsten L. Larson, Stephen Hannon, Leonardo Ubeda, Daniel A. Dale, Simon C. O. Glover, Kathryn Grasha, Ralf S. Klessen, J. M. Diederik Kruijssen, Erik Rosolowsky, Andreas Schruba, Richard L. White, Thomas G. Williams
Summary: The study introduces an innovative approach for detecting and classifying stellar clusters in the PHANGS-HST program, utilizing the Multiple Concentration Index (MCI) parameter to distinguish cluster candidates from stars and incorporating Machine Learning for improved selection accuracy. Performance comparisons with LEGUS show high agreement in cluster identification, with subtle differences attributed to specific project choices. The ML-classified catalogues in PHANGS-HST reach fainter magnitudes and lower stellar masses, suggesting improved efficiency compared to human classification.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
S. Avdan, A. Akyuz, S. Acar, I. Akkaya Oralhan, S. Allak, N. Aksaker
Summary: We investigated the connection between types of X-ray binaries (XRBs) and the properties of compact star clusters in NGC 628. Using Chandra data, we detected 75 X-ray sources, including 69 XRBs and one ultraluminous X-ray source. We identified optical counterparts for 15 XRBs and classified them as high-mass XRBs (HMXBs), while the others were classified as low-mass XRBs (LMXBs). We also identified and analyzed 864 compact star clusters in NGC 628, finding that HMXBs are associated with younger clusters and LMXBs with older clusters.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Tony Junjing Fan, Dae-Sik Moon, Hong Soo Park, Dennis Zaritsky, Sang Chul Kim, Youngdae Lee, Ting S. Li, Yuan Qi Ni, Jeehye Shin, Sang-Mok Cha, Yongseok Lee
Summary: We have discovered 48 new galaxies and analyzed 55 galaxies, including seven previously discovered dwarf galaxy candidates around the giant spiral galaxy NGC 2997. The characteristics and distribution of these galaxies suggest recent accretion of new massive members and that the brighter members have younger stellar populations and higher star formation activities.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)