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, Jose G. Fernandez-Trincado, Dante Minniti, Harinder P. Singh, Luca Sbordone, Andres E. Piatti, Celine Reyle
Summary: This study aims to search for extratidal stars in Galactic globular clusters NGC 6397, NGC 2808, and NGC 6266 using photometry and proper motion measurements from the Gaia DR2 database. The study found extratidal candidate stars outside the tidal radii of all three clusters, with different spatial distributions and potential causes for the presence of these stars.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Sviatoslav B. Borisov, Igor V. Chilingarian, Evgenii V. Rubtsov, Cedric Ledoux, Claudio Melo, Kirill A. Grishin, Ivan Yu. Katkov, Vladimir S. Goradzhanov, Anton V. Afanasiev, Anastasia V. Kasparova, Anna S. Saburova
Summary: We present reprocessed flux-calibrated spectra of 406 stars from the UVES-POP stellar library, which can be used for stellar population synthesis. The spectra have two versions with different spectral resolving powers. The raw spectra were re-reduced using the latest version of the UVES data reduction pipeline with additional algorithms, resulting in significant improvements compared to the original release.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2023)
Article
Astronomy & Astrophysics
Viswajith Vanaraj, Florian Niederhofer, Paul Goudfrooij
Summary: Analyzing Large Magellanic Cloud and Galactic globular clusters reveals that the formation of multiple stellar populations might have a minor connection to the galaxy environment.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
M. Rejkuba, W. E. Harris, L. Greggio, D. Crnojevic, G. L. H. Harris
Summary: The extended stellar halos of galaxies contain important clues for investigating their assembly history and evolution. We investigate the resolved stellar content and the extended halo of NGC 5128 as a function of galactocentric distance, and trace the halo outward to its currently detectable limits.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
David Martinez-Delgado, Santi Roca-Fabrega, Juan Miro-Carretero, Maria Angeles Gomez-Flechoso, Javier Roman, Giuseppe Donatiello, Judy Schmidt, Dustin Lang, Mohammad Akhlaghi, Mark Hanson
Summary: This article studies the low surface brightness stellar structures around the tidal ring galaxy NGC 922 and revises the hypothesis of its formation based on new data. The study reveals that the low surface brightness tidal structures around NGC 922 are more complex than previously reported, with one strong structure not connected to the intruder PGC 3080368, but formed from the tidal disruption of a different satellite. Additionally, a tidal shell around the dwarf galaxy PGC 3080368 is discovered, possibly indicating a recent merger with a smaller satellite.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
J. Schiappacasse-Ulloa, Sara Lucatello, M. J. Rain, Adriano Pietrinferni
Summary: This paper presents a chemical abundance analysis of 217 stars in the metal-poor globular cluster NGC 6752 and explores the characteristics and correlations of stars with high aluminum and lithium content.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
M. McKenzie, D. Yong, A. F. Marino, S. Monty, E. Wang, A. Karakas, A. P. Milone, M. Legnardi, I. U. Roederer, S. Martell, D. Horta
Summary: High-quality VLT/UVES spectra of six red giant branch stars in M22 reveal variations in abundance of elements such as Fe, Na, and Si. The study suggests that M22 hosts two stellar populations with abundance differences, possibly indications of a nuclear star cluster, merged clusters, or an original building block of the Milky Way.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
F. Martins, W. Chantereau, C. Charbonnel
Summary: This study investigates the accuracy of present-day photometric methods in inferring the helium content of multiple populations in NGC 6752. The research shows that it is unlikely that stars more helium-rich than the current observational limit of about 0.3 (in mass fraction) are present in the cluster, even when considering extreme scenarios and rare stars.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Eugenio Carretta
Summary: NGC 4833 is a metal-poor Galactic globular cluster with extreme chemical composition, including a broad Na-O anti-correlation and significant excesses of Ca and Sc. The study confirms that self-enrichment from first generation polluters occurred at high temperatures, producing species such as K and possibly Ca. The abundance of potassium in GCs appears to be related to other elements, indicating a complex chemical pattern in multiple stellar populations.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Mark Gieles, Oleg Y. Gnedin
Summary: Stellar-mass black holes can be retained in globular clusters until the present time. The mass-loss rate in globular cluster evolution is higher when black holes are present, especially near dissolution. We use a parametrized mass-loss rate based on N-body simulations to evolve an initial globular cluster mass function to an age of 12 billion years. The density profile of the mass lost from massive globular clusters resembles that of nitrogen-rich stars in the halo, confirming their origin from globular clusters. Including the effect of black holes reduces the need for additional disruption mechanisms in shaping the globular cluster mass function.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Eugenio Carretta, Angela Bragaglia
Summary: We present the abundance analysis of 185 giants in the bulge globular cluster NGC 6388, showing that a single class of polluters can explain the anti-correlations among light elements. The abundance pattern of other elements in NGC 6388 is similar to bulge field stars, ruling out an accreted origin. The neutron-capture elements show overall uniformity, with a scatter in the [Zr/Fe] ratio correlated to Na and Al abundances.
ASTRONOMY & ASTROPHYSICS
(2023)
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
M. Tailo, E. Corsaro, A. Miglio, J. Montalban, K. Brogaard, A. P. Milone, A. Stokholm, G. Casali, A. Bragaglia
Summary: In this study, a new asteroseismic analysis based on K2 mission data was conducted on stars in the globular cluster M4, leading to the detection of solar-like oscillations in a large sample of 37 stars. By combining asteroseismology and multi-band photometry, estimates of mass and radius were obtained, in agreement with independent sources, reaffirming the reliability of asteroseismology in low metallicity regimes. The study also revealed important information about the mass differences between stellar populations in M4 and the presence of a mass-temperature gradient in red horizontal branch stars, providing valuable insights into the cluster's evolution.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
G. Valle, M. Dell'Omodarme, E. Tognelli
Summary: This study explores the analysis methods for multiple stellar populations in globular clusters, using NGC 2808 as a case study. By employing established statistical clustering methods and addressing the issue of measurement errors, the results obtained differ from those reported in previous literature. The findings suggest that the existence of multiple populations is reliable in high-resolution spectroscopy data, but questionable in low-resolution spectroscopy data. Additionally, it is revealed that the commonly used histogram analysis is prone to generating false-positive findings. Therefore, the use of statistically grounded methods is crucial for conducting more robust and reproducible research.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
C. E. Barbosa, C. Spiniello, M. Arnaboldi, L. Coccato, M. Hilker, T. Richtler
Summary: The variation of the IMF at its low-mass end is not due to kinematical, dynamical, or global properties in NGC 3311. The relation between the IMF slope and the local stellar velocity dispersion is spatially coincidental, while the IMF is closely correlated with stellar age and galactocentric radius.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
C. E. Barbosa, C. Spiniello, M. Arnaboldi, L. Coccato, M. Hilker, T. Richtler
Summary: Researchers investigated the presence of a surviving high-z compact progenitor component in the galaxy NGC 3311 by mapping its 2D kinematics and stellar population, aiming to understand the formation of its structural components and trace their mass assembly history.
ASTRONOMY & ASTROPHYSICS
(2021)
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
Karina T. Voggel, Anil C. Seth, Holger Baumgardt, Bernd Husemann, Nadine Neumayer, Michael Hilker, Renuka Pechetti, Steffen Mieske, Antoine Dumont, Iskren Georgiev
Summary: A dual supermassive black hole system was discovered in NGC 7727, with one located at the optical center of the galaxy and the other offset from the main nucleus by 500pc.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Avinash Chaturvedi, Michael Hilker, Michele Cantiello, Nicola R. Napolitano, Glenn van de Ven, Chiara Spiniello, Katja Fahrion, Maurizio Paolillo, Massimiliano Gatto, Thomas Puzia
Summary: The Fornax cluster offers a unique opportunity to study the formation and evolution of early-type galaxies in a dense environment. Through spectroscopic analysis, we found distinct differences in the kinematic properties of red and blue globular clusters.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Yiming Wu, Chengze Liu, Eric W. Peng, Youkyung Ko, Patrick Cote, Rashi Jain, Laura Ferrarese, Xiaohu Yang, Ariane Lancon, Thomas Puzia, Sungsoon Lim
Summary: By combining data from the ACS Virgo Cluster Survey and the Next Generation Virgo cluster Survey, this study investigates the color gradients of the globular cluster systems in the two most massive galaxies, M87 and M49, in the Virgo cluster. The findings reveal significant negative color gradients up to large radii, driven primarily by a decrease in the ratio of red to blue globular cluster numbers. Similar color gradients are observed in the red and blue subpopulations of globular clusters separately. Additionally, the study uncovers a negative color gradient in the low-mass elliptical satellite galaxies, where those closer to the center of the host galaxy tend to have redder color indices for both their stars and globular clusters. The observed color gradient in the globular cluster system can be explained by the accretion of stars and globular clusters from low-mass satellite galaxies during the second phase of massive early-type galaxy formation.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Youkyung Ko, Eric W. Peng, Patrick Cote, Laura Ferrarese, Chengze Liu, Alessia Longobardi, Ariane Lancon, Roberto P. Munoz, Thomas H. Puzia, Karla A. Alamo-Martinez, Laura Sales, Felipe Ramos-Almendares, Mario G. Abadi, Myung Gyoon Lee, Ho Seong Hwang, Nelson Caldwell, John P. Blakeslee, Alessandro Boselli, Jean-Charles Cuillandre, Pierre-Alain Duc, Susana Eyheramendy, Puragra Guhathakurta, Stephen Gwyn, Andres Jordan, Sungsoon Lim, Ruben Sanchez-Janssen, Elisa Toloba
Summary: This study investigates the stellar populations of globular clusters (GCs) in the core area near M87 in the Virgo Cluster. The mean age, total metallicity, and alpha-element abundance of blue and red GCs show radial and azimuthal variations. Blue GCs exhibit a steep metallicity gradient, while red GCs have a shallower gradient driven by iron abundance. Simulations suggest that more massive satellites sink further into the central galaxy, leading to gradient flattening. The dense environment around M87 and the mass range of GC progenitors influence their gradients. Red GCs in the northwest of M87 are found to be slightly more metal-rich.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Snehalata Sahu, Annapurni Subramaniam, Gaurav Singh, Ramakant Yadav, Aldo R. Valcarce, Samyaday Choudhury, Sharmila Rani, Deepthi S. Prabhu, Chul Chung, Patrick Cote, Nathan Leigh, Aaron M. Geller, Sourav Chatterjee, N. Kameswara Rao, Avrajit Bandyopadhyay, Michael Shara, Emanuele Dalessandro, Gajendra Pandey, Joesph E. Postma, John Hutchings, Mirko Simunovic, Peter B. Stetson, Sivarani Thirupathi, Thomas Puzia, Young-Jong Sohn
Summary: In this study, we present the first results of eight globular clusters based on observations from the AstroSat/UVIT Legacy Survey programme. By combining data from multiple telescopes, we investigate the stellar populations and evolution of these clusters. The color-magnitude diagrams provide valuable information on the distribution and characteristics of the stars, as well as the variations in helium abundance.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
G. Riccio, M. Paolillo, M. Cantiello, R. D'Abrusco, X. Jin, Z. Li, T. Puzia, S. Mieske, D. J. Prole, E. Iodice, G. D'Ago, M. Gatto, M. Spavone
Summary: In this study, the intra-cluster population of low-mass X-ray binaries (LMXB) residing in globular clusters (GC) in the Fornax galaxy cluster were investigated. The results showed that LMXBs tend to form in red and bright GCs. The likelihood of a red GC hosting an LMXB decreases with galactocentric distance, while bright LMXBs are deficient in blue intra-cluster GCs. The spectral properties of GC-LMXBs were also found to differ between intra-cluster and host-galaxy samples.
ASTRONOMY & ASTROPHYSICS
(2022)
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
Deepthi S. Prabhu, Annapurni Subramaniam, Snehalata Sahu, Chul Chung, Nathan W. C. Leigh, Emanuele Dalessandro, Sourav Chatterjee, N. Kameswara Rao, Michael Shara, Patrick Cote, Samyaday Choudhury, Gajendra Pandey, Aldo A. R. Valcarce, Gaurav Singh, Joesph E. Postma, Sharmila Rani, Avrajit Bandyopadhyay, Aaron M. Geller, John Hutchings, Thomas Puzia, Mirko Simunovic, Young-Jong Sohn, Sivarani Thirupathi, Ramakant Singh Yadav
Summary: We conducted the first comprehensive study of the far-ultraviolet (FUV) characteristics of Omega Centauri, the most massive globular cluster. Comparing the FUV-optical color-magnitude diagrams with canonical models, we found discrepancies in the properties of horizontal branch (HB) stars and white dwarfs (WDs) between observations and predictions. Our simulations revealed a radial segregation of younger He-rich subpopulations, indicating enrichment from older generations. We also observed that some hHBs in Omega Cen are less massive than their counterparts in M13, consistent with previous spectroscopic studies. This study provides important constraints for understanding the formation models of Omega Cen.
ASTROPHYSICAL JOURNAL LETTERS
(2022)
Article
Astronomy & Astrophysics
Rosa A. Gonzalez-Lopezlira, Luis Lomeli-Nunez, Yasna Ordenes-Briceno, Laurent Loinard, Stephen Gwyn, Karla Alamo-Martinez, Gustavo Bruzual, Ariane Lancon, Thomas H. Puzia
Summary: This study explores the relationship between the total number of globular clusters and the central black hole mass in spiral galaxies, and observes the consistency between elliptical and late-type galaxies in this parameter space, suggesting that black holes and galaxies coevolve through calm accretion, active galactic nuclei feedback, and other secular processes.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Gaspar Galaz, David T. Frayer, Matias Blana, J. Christopher Howk, Thomas Puzia, Evelyn J. Johnston, Yasna Ordenes-Briceno, Sarah Church, Santiago Gil, Katerine Joachimi, Marcelo Mora
Summary: This study presents the results of GBT/ARGUS (CO)-C-12(1-0) observations on the giant low surface brightness galaxy Malin 1, providing an upper limit for its CO mass and revealing significant differences in the physical conditions of the interstellar medium compared to normal galaxies.
ASTROPHYSICAL JOURNAL LETTERS
(2022)
Article
Astronomy & Astrophysics
Mirko Simunovic, Thomas H. H. Puzia, Bryan Miller, Eleazar R. R. Carrasco, Aaron Dotter, Santi Cassisi, Stephanie Monty, Peter Stetson
Summary: This study presents a photometric analysis of globular cluster 47 Tuc (NGC 104) using near-IR imaging data. The analysis combines near-IR photometry from the GeMS/ GSAOI Galactic Globular Cluster Survey with optical photometry from the Hubble Space Telescope, resulting in a high-quality color-magnitude diagram. Bayesian analysis using the BASE-9 software provides probability distributions and precise estimates for the cluster's age, distance, and extinction parameters. The estimated age of 47 Tuc is 12.42(-0.05)(+0.05)+/- 0.08 Gyr, and the true distance modulus is (m-M)0= 13.250-(+ 0.003)(-0.003) +/- 0.028 mag, consistent with previous studies.
ASTROPHYSICAL JOURNAL
(2023)
Proceedings Paper
Astronomy & Astrophysics
Gaetano Sivo, Julia Scharwachter, Manuel Lazo, Celia Blain, Stephen Goodsell, Marcos van Dam, Martin Tschimmel, Henry Roe, Jennifer Lotz, Kim Tomassino-Reed, William Rambold, Courtney Raich, Ricardo Cardenes, Angelic Ebbers, Tim Gaggstatter, Pedro Gigoux, Thomas Schneider, Charles Cavedoni, Stacy Kang, Stanislas Karewicz, Heather Carr, Jesse Ball, Paul Hirst, Emmanuel Chirre, John White, Lindsay Magill, Molly Grogan, Anne Jordan, Suresh Sivanandam, Masen Lamb, Adam Muzzin, Eduardo Marin, Scott Chapman, Jennifer Dunn, Dan Kerley, Jean-Pierre Veran, Morten Andersen, Franck Marchis, Ruben Diaz, John Blakeslee, Michael Pierce, Rodrigo Carrasco, Hwyhyun Kim, Anja Feldmeier-Krause, Alan McConnachie, James Jee, Wesley Fraser, Mark Ammons, Christopher Packham, John Bally, Trent Dupuy, Daniel Huber, Marie Lemoine-Busserole, Thomas Puzia, Paolo Turri, Chadwick Trujillo, Janice Lee
Summary: GNAO is an upcoming adaptive optics facility that will provide state-of-the-art AO system for Gemini North, catering to surveys and time domain science in the era of JWST and Rubin operations. It will optimize the Gemini infrared Multi Object Spectrograph (GIRMOS) and also include the development of a new laser guide star facility and other associated projects.
ADAPTIVE OPTICS SYSTEMS VIII
(2022)