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
Ivan S. Gerasimov, Oleg Egorov, Tatiana A. Lozinskaya, Alexei Moiseev, Dmitry Oparin
Summary: Feedback from massive stars has significant impacts on the interstellar medium and galaxy evolution. However, the mechanisms of feedback at small scales, especially in low-metallicity environments, remain poorly understood observationally. This study analyzes the ionized gas in the nearby star-forming galaxy Sextans A and its connection to massive stars. The results reveal expanding superbubbles of ionized gas and provide evidence of feedback from supernovae and the pre-supernova phase.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(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
Richa Kundu, Camila Navarrete, Luca Sbordone, Julio A. Carballo-Bello, Jose G. Fernandez-Trincado, Dante Minniti, Harinder P. Singh
Summary: This study investigates the extra-tidal regions of several globular clusters associated with Sgr dSph and identifies potential extra-tidal candidates. The results suggest that the distribution of extra-tidal stars in these clusters is elongated in the same direction as the local stream, indicating the influence of Sgr's gravitational potential.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Rose A. Finn, Benedetta Vulcani, Gregory Rudnick, Michael L. Balogh, Vandana Desai, Pascale Jablonka, Dennis Zaritsky
Summary: We investigate the role of dense environments in suppressing star formation by studying galaxies with log(10)(M- * / M-?) > 9.7 in nine clusters from the Local Cluster Survey. We find that SFR suppression increases with increasing bulge-to-total ratio in all environments. In addition, cluster and infall galaxies have more suppressed SFRs compared to field counterparts at all values of B/T, suggesting an additional mechanism in dense environments.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
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
J. Roman, P. M. Sanchez-Alarcon, J. H. Knapen, R. Peletier
Summary: We analysed the dwarf galaxy UGC 7346 and found evidence suggesting the formation of a nuclear star cluster (NSC) in its earlier stages. Remnants of a past interaction and concentrated globular cluster (GC) candidates towards the centre of the galaxy support this. The central concentration of GCs is likely produced by the dynamical friction of merger, making UGC 7346 a unique case of NSC formation. These findings provide a natural explanation for the environmental correlations found for the nucleation fraction in early-type dwarf galaxies.
ASTRONOMY & ASTROPHYSICS
(2023)
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
Alina Lescinskaite, Rima Stonkute, Vladas Vansevicius
Summary: The study reveals significant differences in the recent star formation history of the Leo A galaxy over the past 300 million years. The spatial distribution of stars and the relationship with the surrounding interstellar medium indicate recent star-forming activity and the presence of a shock front. Additionally, early-type emission-line stars were identified in the Leo A galaxy.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
E. Busekool, M. A. W. Verheijen, J. M. van der Hulst, R. B. Tully, N. Trentham, M. A. Zwaan
Summary: The study determined the HI mass function of galaxies in the Ursa Major association using VLA and WSRT surveys, revealing a relative lack of low-HI mass galaxies in the region. The slope of the HI mass function in Ursa Major hints at an environmental dependence, which differs from other surveys covering larger volumes and cosmic environments.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Joachim Janz, Heikki Salo, Alan H. Su, Aku Venhola
Summary: The study analyses the color versus surface brightness for galaxies in the Virgo cluster and compares it to the Fornax cluster to examine the impact of ram pressure on galaxy transformation. The results show similarities in the color-surface brightness correlation between the two clusters, indicating a scenario of transformation through the quenching of star formation. However, there are differences in the fraction of early-type galaxies between the Virgo and Fornax clusters, suggesting unique characteristics of the Virgo cluster despite its high mass.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Jose Maria Arroyo-Polonio, Giuseppina Battaglia, Guillaume F. Thomas, Michael J. Irwin, Alan W. McConnachie, Eline Tolstoy
Summary: The aim of this study is to calculate the binary fraction of classical dwarf spheroidal galaxies (dSphs) that are satellites of the Milky Way. The results indicate that the binary fraction of Sculptor is 0.55(-0.19)(+0.17), and emphasize the importance of considering Roche lobe overflow for constraining the period distribution of binary stars.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Matthew D. A. Orkney, Justin Read, Oscar Agertz, Andrew Pontzen, Martin P. Rey, Alex Goater, Ethan Taylor, Stacy Y. Kim, Maxime Delorme
Summary: This study revisits the survival and evolution of EriII's star cluster, focusing on its puzzlingly large ellipticity. The study finds two possible scenarios to explain EriII's star cluster, one being EriII having a low-density dark matter core, and the other being EriII's star cluster orbiting in a partial core and being tidally destroyed. However, the second scenario struggles to explain the large size of EriII's star cluster.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Andres E. Piatti
Summary: By analyzing the space velocity components of SMC clusters, it was found that clusters in SMC tidally induced structures have significantly different velocities, while the oldest SMC cluster NGC 121 is not associated with any SMC tidal features.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Teymoor Saifollahi, Ignacio Trujillo, Michael A. Beasley, Reynier F. Peletier, Johan H. Knapen
Summary: Studies have found that previous estimates of the number of globular clusters around DF44 in the Coma cluster were higher, while new research indicates a lower actual number, consistent with other dwarf galaxies of similar stellar mass, and the dark matter halo mass also matches expectations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
H. Parviainen, E. Palle, M. R. Zapatero-Osorio, G. Nowak, A. Fukui, F. Murgas, N. Narita, K. G. Stassun, J. H. Livingston, K. A. Collins, D. Hidalgo Soto, V. J. S. Bejar, J. Korth, M. Monelli, P. Montanes Rodriguez, N. Casasayas-Barris, G. Chen, N. Crouzet, J. P. de Leon, A. Hernandez, K. Kawauchi, P. Klagyivik, N. Kusakabe, R. Luque, M. Mori, T. Nishiumi, J. Prieto-Arranz, M. Tamura, N. Watanabe, T. Gan, K. I. Collins, E. L. N. Jensen, T. Barclay, J. P. Doty, J. M. Jenkins, D. W. Latham, M. Paegert, G. Ricker, D. R. Rodriguez, S. Seager, A. Shporer, R. Vanderspek, J. Villasenor, J. N. Winn, B. Wohler, I. Wong
Summary: TOI-519 b is a substellar object orbiting an M dwarf, contributing to our understanding of the boundaries of planet formation.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
V Rusakov, M. Monelli, C. Gallart, T. K. Fritz, T. Ruiz-Lara, E. J. Bernard, S. Cassisi
Summary: Through detailed analysis, we found that the star formation history of the Fornax galaxy exhibits sharp bursts and intermittent activity, with differences between different regions, suggesting that tidally induced star formation may be the cause of this phenomenon.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
T. Ruiz-Lara, C. Gallart, M. Monelli, T. K. Fritz, G. Battaglia, S. Cassisi, M. Luis Aznar, A. Russo Cabrera, I Rodriguez-Martin, J. J. Salazar-Gonzalez
Summary: Leo I is considered as one of the youngest dwarf spheroidals in the Local Group, and analysis of its extended star formation history has revealed complexities in its formation process, especially the possible interactions with other systems.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Karla A. Alamo-Martinez, Ana L. Chies-Santos, Michael A. Beasley, Rodrigo Flores-Freitas, Cristina Furlanetto, Marina Trevisan, Allan Schnorr-Mueller, Ryan Leaman, Charles J. Bonatto
Summary: In this study, the globular cluster (GC) systems of 15 massive, compact early-type galaxies (ETGs) were analysed, with 13 identified as relic galaxy candidates. These candidates are likely nearby counterparts of high-redshift red nugget galaxies. The results show lower specific frequencies, compact GC half-number radii, and an anticorrelation between the specific angular momentum of the host galaxy and the color distribution width of their GC systems.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
C. Gallart, M. Monelli, T. Ruiz-Lara, A. Calamida, S. Cassisi, M. Cignoni, J. Anderson, G. Battaglia, J. R. Bermejo-Climent, E. J. Bernard, C. E. Martinez-Vazquez, L. Mayer, S. Salvadori, A. Monachesi, J. F. Navarro, S. Shen, F. Surot, M. Tosi, V. Bajaj, G. S. Strinfellow
Summary: Eridanus II (Eri II) is an ultrafaint dwarf galaxy with a star formation history indicating a short burst of star formation responsible for the majority of stellar mass, leading to implications for supernova events and energy injection into the interstellar medium.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
P. Rodriguez-Beltran, A. Vazdekis, M. Cervino, M. A. Beasley
Summary: The study explores the potential of utilizing surface brightness fluctuations (SBF) for studying composite stellar populations (CSP) by calculating models composed of different mass fractions of two single stellar populations. The findings show that combining mean and SBF values simultaneously leads to improved results in revealing small secondary components in elliptical galaxies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Teymoor Saifollahi, Dennis Zaritsky, Ignacio Trujillo, Reynier F. Peletier, Johan H. Knapen, Nicola Amorisco, Michael A. Beasley, Richard Donnerstein
Summary: This study analyses the observations of globular clusters in six ultradiffuse galaxies and evaluates competing formation models. The results suggest that the globular cluster number and distribution in these galaxies are more consistent with dwarf galaxies rather than more massive galaxies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
H. J. Leath, M. A. Beasley, A. Vazdekis, N. Salvador-Rusinol, A. Gvozdenko
Summary: This study investigates the determination of stellar population parameters of extragalactic Globular Clusters through their integrated spectroscopy. Previous observations suggested a splitting phenomenon in the H beta(o) line-strength index of Galactic globular clusters, which was thought to be caused by the presence of Blue straggler stars. However, new findings reveal that this splitting only occurs at intermediate to high metallicities and is due to an increased helium abundance, rather than an increased fraction of Blue straggler stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Matteo Monelli, Giuliana Fiorentino
Summary: This article discusses the use and importance of pulsating variable stars as population tracers in the Local Group galaxies. It focuses on RR Lyrae stars and Anomalous Cepheids, exploring their pulsational properties and how they can be utilized to understand the evolution and star formation history of host galaxies.
Article
Astronomy & Astrophysics
P. Massana, T. Ruiz-Lara, N. E. D. Noel, C. Gallart, D. L. Nidever, Y. Choi, J. D. Sakowska, G. Besla, K. A. G. Olsen, M. Monelli, A. Dorta, G. S. Stringfellow, S. Cassisi, E. J. Bernard, D. Zaritsky, M. -R. L. Cioni, A. Monachesi, R. P. Van der Marel, T. J. L. De Boer, A. R. Walker
Summary: We used the SMASH survey to quantitatively derive the star formation history of the Small Magellanic Cloud (SMC) and found five distinctive peaks of star formation in the last 3.5 billion years. We compared the star formation history of the SMC with that of the Large Magellanic Cloud (LMC) and found clear synchronicity. Tidal interactions between the two galaxies have played an important role in their evolution for the past 3.5 billion years.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
N. Salvador-Rusinol, A. Ferre-Mateu, A. Vazdekis, M. A. Beasley
Summary: By analyzing NGC 1277, researchers shed light on the origin of young stars in massive early-type galaxies and found a similar mass fraction of young stars as in other galaxies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
T. Ruiz-Lara, A. Helmi, C. Gallart, F. Surot, S. Cassisi, S. Cassisi
Summary: By analyzing the star formation histories, we have identified unique characteristics of the past evolution of the progenitor of the Helmi streams. We found that its early star formation lasted longer than that of the Milky Way halo and it was accreted by the Milky Way around 8 billion years ago.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
N. Salvador-Rusinol, M. A. Beasley, A. Vazdekis, F. La Barbera
Summary: The largest and most massive galaxies in the Universe are central cluster galaxies with very old stellar populations, yet studies have found blue cores indicating ongoing star formation. The analysis of nearby massive central galaxies shows a negative gradient in young stellar populations, decreasing with galactocentric distance, suggesting that star formation primarily occurs in galaxy cores within 2 kpc. The gas required for forming these young stars is likely to come from an in situ origin via stellar evolution, as supported by the observed young stellar populations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)