Article
Astronomy & Astrophysics
Charli M. Sakari, George Wallerstein
Summary: This paper presents [Fe/H] ratios for globular clusters in the outer halo of the Andromeda Galaxy based on moderate-resolution, integrated light spectroscopy. The results show that the outer halo globular clusters are generally more metal-poor than typical inner halo globular clusters, with some exceptions that may have been accreted from dwarf satellites. The metallicities of these clusters also provide important constraints on the nature of the substructure in the outer halo and the dwarf satellites responsible for it.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Joshua Peltonen, Erik Rosolowsky, L. Clifton Johnson, Anil C. Seth, Julianne Dalcanton, Eric F. Bell, Jonathan Braine, Eric W. Koch, Margaret Lazzarini, Adam K. Leroy, Evan D. Skillman, Adam Smercina, Tobin Wainer, Benjamin F. Williams
Summary: By comparing young clusters and GMCs in M33 and M31, we can constrain temporal and spatial scales in the star formation process. Young clusters show a high probability of being near other young clusters, while the correlation between GMCs is suppressed by the cloud identification algorithm. Younger clusters are found to be closer to GMCs than older clusters. The total lifetime of the GMCs in M33 is estimated to be approximately 11-15 million years.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
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
Eric W. Koch, Erik W. Rosolowsky, Adam K. Leroy, Jeremy Chastenet, I-Da Chiang, Julianne Dalcanton, Amanda A. Kepley, Karin M. Sandstrom, Andreas Schruba, Sneiana Stanimirovie, Dyas Utomo, Thomas G. Williams
Summary: Previous estimates of galaxy atomic gas mass from 21-cm HI emission are systematically low and require correction due to the presence of a cold opaque atomic gas component. New observations show a preference for a multiple-component Gaussian model over a single opacity-corrected model, challenging previous assumptions. Further studies are needed to better understand the implications of these findings on the opaque atomic ISM mass and HI surface density relationships.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Dayi Li, Pauline Barmby
Summary: The study demonstrates the power of Gibbs point process models in analyzing the spatial distributions of objects in the star formation complexes of resolved galaxies, revealing the high correlation between GMCs and YSCCs. The spatial distribution of YSCCs exhibits a clustering pattern with a peak at about 250pc scale, mainly in regions with galactocentric distance greater than 4.5kpc. The properties of GMCs, such as galactocentric distance and mass, have a strong positive effect on the correlation strength between GMCs and YSCCs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Charli M. Sakari, Matthew D. Shetrone, Andrew McWilliam, George Wallerstein
Summary: G1 is a massive star cluster in M31 with moderately metal-poor abundance, alpha enhancement, and unique signatures of Na and Al enrichment, suggesting its origin in a fairly massive galaxy and intimate connection with globular cluster formation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Shoucheng Wang, Bingqiu Chen, Jun Ma
Summary: Determining the metallicities and ages of M31 clusters is crucial for understanding the formation and evolution of the M31 galaxy. Utilizing LAMOST spectra and multi-band photometry data, a new algorithm was developed to estimate metallicities and ages of 346 M31 clusters. The study successfully derived parameters for 53 young and 293 old clusters, with results in good agreement with existing literature and also providing new age and metallicities data for a significant number of sources.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Jiaming Pan, Eric F. Bell, Adam Smercina, Paul Price, Colin T. Slater, Jeremy Bailin, Roelof S. de Jong, Richard D'Souza, In Sung Jang, Antonela Monachesi
Summary: The study focuses on the outer halo globular cluster populations and their significance in understanding galaxy merging, GC accretion, and the origin of GCs. By utilizing Subaru Hyper Suprime-Cam (HSC) data, GALEX, IRAC, and Gaia EDR3 data, candidate GCs in the M81 group's outer halo were selected for confirmation and future research. The findings suggest that known GCs in the M81 group have slightly larger sizes than the Subaru PSF, and their colors in optical bands are only slightly different from stars. The inclusion of archival IRAC data greatly improves the separation of GCs from stars and compact background galaxies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Shoucheng Wang, Jun Ma
Summary: By conducting deep observations of the brightest globular cluster (GC1) in M 81, researchers have determined its age to be 13.0 +/- 2.90 billion years and mass to be 1.06-1.48x10^7 solar masses. The R-h vs M-V diagram suggests that GC1 is more likely an accreted former nuclear star cluster rather than a classical globular cluster like the majority found in the Milky Way.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Dante Minniti, Jose G. Fernandez-Trincado, Matias Gomez, Leigh C. Smith, Philip W. Lucas, Rodrigo Contreras Ramos
Summary: We report the discovery of VVV-CL160, a new nearby globular cluster with extreme kinematics, and suggest it may be associated with the extension of the Hrid halo stream, along with NGC 6544.
ASTRONOMY & ASTROPHYSICS
(2021)
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
Breanna A. Binder, Ashley K. Anderson, Kristen Garofali, Margaret Lazzarini, Benjamin F. Williams
Summary: We analyzed the spatial correlation of HMXB and YSC populations in M31 and M33 and found a higher degree of correlation than expected by chance. This correlation is also related to the specific star formation rate of the host galaxy. Our X-ray stacking analysis did not detect excess X-ray emission at the locations of YSCs, indicating that dynamical formation within YSCs is not a major channel for HMXB formation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
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
Chia-Hsuan Cheng, Ing-Guey Jiang
Summary: To study the dynamical properties of globular clusters, researchers analyzed the surface brightness and kinematic data using limepy models. They determined the concentration, truncation, and anisotropy of 18 globular clusters, as well as other parameters such as cluster mass and distance. While limepy models provided a good fit for most clusters, NGC 5139 and NGC 6388 may require more advanced models considering intermediate-mass black holes. However, the model with some degree of anisotropy fit well with the data of NGC 7078. Moreover, the study revealed a strong concentration-truncation anticorrelation and a truncation-semimajor-axis correlation, indicating the dynamical evolution of globular clusters.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Ali Rostami Shirazi, Hosein Haghi, Pouria Khalaj, Ahmad Farhani Asl, Akram Hasani Zonoozi
Summary: Using numerical simulations, this study investigates the escape of globular clusters from satellite dwarf spheroidal galaxies of the Milky Way. The research finds correlations between the escape fraction of globular clusters and the mass, orbital eccentricity, and apogalactic distance of the galaxies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)