Article
Astronomy & Astrophysics
S. Taibi, G. Battaglia, R. Leaman, A. Brooks, C. Riggs, F. Munshi, Y. Revaz, P. Jablonka
Summary: This study explores the correlations between metallicity gradients in Local Group dwarf galaxies and their stellar mass, star formation history timescales, and environment. The results show that there are no statistical differences in metallicity gradients based on the morphological type of the galaxies or their distance from the Milky Way or M31. Furthermore, there are no correlations found with stellar mass or star formation timescales. The strongest gradients are observed in systems that are likely to have experienced a past merger event.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
C. R. Higgs, A. W. McConnachie, N. Annau, M. Irwin, G. Battaglia, P. Cote, G. F. Lewis, K. Venn
Summary: The study analyzed the 12 closest Solo dwarf galaxies accessible from the Northern hemisphere, including their distances, spatial distributions, morphology, and extended structures. The results show that most of these galaxies can be well described by two-dimensional Sersic functions, but there are also some galaxies that show tentative evidence of two distinct components. Additionally, no prominent extended stellar substructures were identified in the outer regions of any of the systems examined.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Review
Astronomy & Astrophysics
Giuseppina Battaglia, Carlo Nipoti
Summary: This article reviews the properties of dwarf galaxies in the Local Group, focusing on their stellar dynamics and dark matter content and distribution. The combination of observed data and dynamical models reveals that these galaxies are mostly dominated by dark matter halos, making them valuable for studying the nature of dark matter.
Article
Astronomy & Astrophysics
Sasha R. Brownsberger, Lisa Randall
Summary: This study introduces a method to measure the correspondence between dark matter models and observations of stellar populations in dwarf galaxies without assuming a parametric stellar distribution. Through this method, researchers found the consistency of different shapes and distributions of dark matter models with stellar data, as well as their consistency with stellar positions and velocities. Interestingly, the Fornax dwarf spheroidal galaxy shows no evidence of a disc-like structure and exhibits some features that are inconsistent with predictions from Lambda cold dark matter with baryon simulations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Alis J. Deason, Sownak Bose, Azadeh Fattahi, Nicola C. Amorisco, Wojciech Hellwing, Carlos S. Frenk
Summary: This study investigates the merger history of dwarf-mass galaxies using simulations and empirical models. It shows that the number of major and minor mergers, as well as the number of mergers that bring in stars, depend on the type of dark matter and the galaxy occupation model. The research also highlights the importance of the galaxy formation threshold in determining the growth of stellar haloes.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Federico Sestito, Daria Zaremba, Kim A. Venn, Lina D'Aoust, Christian Hayes, Jaclyn Jensen, Julio F. Navarro, Pascale Jablonka, Emma Fernandez-Alvar, Jennifer Glover, Alan W. Mcconnachie, Andre-Nicolas Chene
Summary: Stellar candidates in the extreme outskirts of the Ursa Minor dwarf galaxy have been discovered and confirmed to be part of the galaxy through observations and chemical analysis. The chemical patterns in UMi suggest an outside-in star-formation history and a low star-formation efficiency. Additionally, the analysis of the surface number density profile indicates that UMi's outskirts have been influenced by tidal effects.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Multidisciplinary Sciences
Guido Roberts-Borsani, Tommaso Treu, Wenlei Chen, Takahiro Morishita, Eros Vanzella, Adi Zitrin, Pietro Bergamini, Marco Castellano, Adriano Fontana, Karl Glazebrook, Claudio Grillo, Patrick L. Kelly, Emiliano Merlin, Themiya Nanayakkara, Diego Paris, Piero Rosati, Lilan Yang, Ana Acebron, Andrea Bonchi, Kit Boyett, Marusa Bradac, Gabriel Brammer, Tom Broadhurst, Antonello Calabro, Jose M. Diego, Alan Dressler, Lukas J. Furtak, Alexei V. Filippenko, Alaina Henry, Anton M. Koekemoer, Nicha Leethochawalit, Matthew A. Malkan, Charlotte Mason, Amata Mercurio, Benjamin Metha, Laura Pentericci, Justin Pierel, Steven Rieck, Namrata Roy, Paola Santini, Victoria Strait, Robert Strausbaugh, Michele Trenti, Benedetta Vulcani, Lifan Wang, Xin Wang, Rogier A. Windhorst
Summary: In the early universe, sources of ultraviolet photons played a crucial role in ionizing intergalactic hydrogen, making the universe transparent to UV radiation. Fainter galaxies that are surrounded by neutral gas were believed to dominate the photon budget. By using the James Webb Space Telescope and gravitational lensing, the ultra-faint galaxy JD1 was spectroscopically confirmed at a redshift of z = 9.79, showing a compact and complex morphology with low stellar mass and subsolar metallicity.
Article
Astronomy & Astrophysics
Elias K. Oakes, Taylor J. Hoyt, Wendy L. Freedman, Barry F. Madore, Quang H. Tran, William Cerny, Rachael L. Beaton, Mark Seibert
Summary: In this study, the authors determined the distance modulus of the Fornax dwarf spheroidal galaxy using ground-based imaging and proper motion observations. They used multiple methods to calibrate and validate the results, and obtained a distance of 143 +/- 3 kpc for the galaxy.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Guy Worthey, Xiang Shi
Summary: Integrated light models incorporating chemically peculiar stars improve accuracy of recovered stellar population parameters, but do not show unique age information from CP star features compared to other methods. Some local group galaxies have older stellar populations, while NGC 205 stands out for its younger component.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
David A. Kinson, Joana M. Oliveira, Jacco Th van Loon
Summary: A supervised machine learning methodology was used to classify stellar populations in NGC6822, achieving high accuracy in identifying different target classes. The study confirmed the nature of known YSO candidates, identified new YSOs, and characterized the star formation environment in the galaxy. The PRF analysis also definitively classified non-YSO candidates and explored the potential of unsupervised methods for stellar population identification.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
David A. Kinson, Joana M. Oliveira, Jacco Th van Loon
Summary: We used the Probabilistic Random Forest (PRF) methodology to classify stellar populations in the Local Group spiral galaxy M33. By utilizing both near and far-IR classification features, we accurately classified sources into nine main target classes, identified star forming regions, and estimated star formation rates and masses using photometric measurements and established evolutionary sequences.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
E. Cukanovaite, P-e Tremblay, S. Toonen, K. D. Temmink, Christopher J. Manser, M. W. O'Brien, J. McCleery
Summary: We use the Gaia-defined 40 pc white dwarf sample to derive the local stellar formation history. This is the largest sample of white dwarfs with available spectroscopy, allowing for classification of chemical abundances and accurate determination of atmospheric parameters. Our population synthesis model shows that a uniform stellar formation history over the past 10.5 billion years fits well with the observed distribution of absolute Gaia G magnitudes. We test the robustness of our model by varying several assumptions, and find that the relative stellar formation rate is not significantly affected, although the onset of stellar formation is sensitive to input parameters like white dwarf cooling models.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Sergey Khoperskov, Ivan Minchev, Noam Libeskind, Misha Haywood, Paola Di Matteo, Vasily Belokurov, Matthias Steinmetz, Facundo A. Gomez, Robert J. J. Grand, Yehuda Hoffman, Alexander Knebe, Jenny G. Sorce, Martin Spaare, Elmo Tempel, Mark Vogelsberger
Summary: This study explores the phase-space structure of merged stars by analyzing six analogues of M31/MW, finding significant overlaps between merger remnants and in situ stars in different coordinate systems. Moreover, the positions of merger debris frequently change with time. An age gradient is observed in the L-z-E coordinate system, allowing for the use of stellar ages to determine the date of merger events. Accreted stars can be identified using root J(r) values, and different merger debris can be better distinguished from each other and in situ stars using the (J(z)/J(r)-orbital eccentricity) kinematic space.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Nikhil Arora, Andrea Maccio, Stephane Courteau, Tobias Buck, Noam Libeskind, Jenny G. Sorce, Chris B. Brook, Yehuda Hoffman, Gustavo Yepes, Edoardo Carlesi, Connor Stone
Summary: Recent studies of dwarf galaxies in the Local Group have revealed their unique characteristics in star formation history, stellar metallicity, gas content, and kinematics. Simulation results show that Local Group dwarf galaxies have similar total gas mass and stellar properties compared to field galaxies. However, they have more cold gas in their central parts and more metal-rich gas in the halo, likely due to interactions with other dwarfs in the high-density environment of the Local Group. Metal diffusion does not significantly impact the chemical evolution of Local Group dwarf galaxies. These findings highlight the importance of studying the stellar components of Local Group dwarfs for understanding galaxy formation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
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
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
Ricardo Herbonnet, Adrian Crawford, Camille Avestruz, Elena Rasia, Carlo Giocoli, Massimo Meneghetti, Anja von Der Linden, Weiguang Cui, Gustavo Yepes
Summary: The shape and orientation of galaxy clusters play an important role in improving weak-lensing mass estimates.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Nikhil Arora, Andrea Maccio, Stephane Courteau, Tobias Buck, Noam Libeskind, Jenny G. Sorce, Chris B. Brook, Yehuda Hoffman, Gustavo Yepes, Edoardo Carlesi, Connor Stone
Summary: Recent studies of dwarf galaxies in the Local Group have revealed their unique characteristics in star formation history, stellar metallicity, gas content, and kinematics. Simulation results show that Local Group dwarf galaxies have similar total gas mass and stellar properties compared to field galaxies. However, they have more cold gas in their central parts and more metal-rich gas in the halo, likely due to interactions with other dwarfs in the high-density environment of the Local Group. Metal diffusion does not significantly impact the chemical evolution of Local Group dwarf galaxies. These findings highlight the importance of studying the stellar components of Local Group dwarfs for understanding galaxy formation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Daniel Forero-Sanchez, Chia-Hsun Chuang, Sergio Rodriguez-Torres, Gustavo Yepes, Stefan Gottloeber, Cheng Zhao
Summary: The increase in observed volume in cosmological surveys presents challenges for simulation preparations, as large-volume simulations are computationally intractable and higher mass resolutions are needed. This study proposes a machine learning approach to calibrate low-resolution simulations using paired high-resolution simulations, which allows for improved mass resolution without the computational burden. The calibrated simulations accurately reproduce the mass-clustering relation within a certain scale range.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Weiguang Cui, Romeel Dave, Alexander Knebe, Elena Rasia, Meghan Gray, Frazer Pearce, Chris Power, Gustavo Yepes, Dhayaa Anbajagane, Daniel Ceverino, Ana Contreras-Santos, Daniel de Andres, Marco De Petris, Stefano Ettori, Roan Haggar, Qingyang Li, Yang Wang, Xiaohu Yang, Stefano Borgani, Klaus Dolag, Ying Zu, Ulrike Kuchner, Rodrigo Canas, Antonio Ferragamo, Giulia Gianfagna
Summary: We introduce GIZMO-SIMBA, a new suite of galaxy cluster simulations within THE THREE HUNDRED project. Comparing to THE THREE HUNDRED zooms run with GADGET-X, GIZMO-SIMBA generally provides a good match to available data at z approximate to 0. GIZMO-SIMBA's unique black hole growth and feedback model yields agreement with the observed BH scaling relations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
S. Nepal, G. Guiglion, R. S. de Jong, M. Valentini, C. Chiappini, M. Steinmetz, M. Ambrosch, E. Pancino, R. D. Jeffries, T. Bensby, D. Romano, R. Smiljanic, M. L. L. Dantas, G. Gilmore, S. Randich, A. Bayo, M. Bergemann, E. Franciosini, F. Jimenez-Esteban, P. Jofre, L. Morbidelli, G. G. Sacco, G. Tautvaisiene, S. Zaggia
Summary: In this study, a convolutional neural network (CNN) was used to predict atmospheric parameters and lithium abundances for nearly 40,000 stars by combining Gaia-ESO Survey iDR6 stellar labels and GIRAFFE HR15N spectra. The results show that the CNN effectively learns the physics of the stellar labels and successfully identifies the lithium feature in the GIRAFFE HR15N setup. This approach provides a useful tool for future spectroscopic surveys.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Matthew Pereira-Wilson, Julio F. Navarro, Alejandro Benitez-Llambay, Isabel Santos-Santos
Summary: In this study, the role of the cosmic UV background in regulating star formation in low-mass Lambda CDM haloes has been examined using the APOSTLE cosmological simulations. The results show that star formation primarily occurs in haloes whose mass exceeds a redshift-dependent 'critical' mass, determined by the structure of the haloes and the thermal pressure of UV-heated gas. The discovery of a population of faint field dwarfs lacking ongoing star formation would provide strong support for these findings.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Georg Herzog, Alejandro Benitez-Llambay, Michele Fumagalli
Summary: We examine the gas content of field dwarf galaxies in a high-resolution cosmological simulation and find that low-mass dark matter haloes host quiescent galaxies with low gas content. The gas deficiency in these galaxies is caused by interactions with larger hosts and hydrodynamic interactions with the cosmic web. This deficit of gas may hinder the detection of a significant fraction of field dwarfs in future surveys.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Tomas Hough, Sofia A. Cora, Roan Haggar, Cristian Vega-Martinez, Ulrike Kuchner, Frazer Pearce, Meghan Gray, Alexander Knebe, Gustavo Yepes
Summary: In this study, the semi-analytic model of galaxy formation and evolution SAG is combined with 102 simulated galaxy clusters from THE THREE HUNDRED project to investigate the relationship between star formation quenching and the dynamical history of galaxies in and around clusters. Galaxies are classified into four populations based on their orbital history, and it is found that the majority of quenched galaxies inside clusters are ancient infallers with low or no hot and cold gas content. The quenching of ancient infallers is mainly caused by ram-pressure stripping (RPS) between the first and second pericentric passages. Recent infallers make up a smaller fraction of quenched galaxies inside clusters, and they tend to have a higher proportion of hot and cold gas. Pre-processing effects contribute to the quenching of recent infallers before they enter the main cluster progenitor. Backsplash galaxies, which account for about 65% of quenched galaxies around clusters, require both pre-processing and in-cluster processes to suppress star formation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Laurent Legrand, Pratika Dayal, Anne Hutter, Stefan Gottloeber, Gustavo Yepes, Maxime Trebitsch
Summary: Using the ASTRAEUS framework, the impact of environmental density and radiative feedback on the assembly of galaxies and their host halos during the Epoch of Reionization is explored. It is found that there is a specific environment where galaxies are most efficient at accreting dark matter, minor mergers contribute more to dark matter assembly at z=5, and radiative feedback suppresses star formation in low-mass galaxies in over-dense environments.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Oliver Newton, Arianna Di Cintio, Salvador Cardona-Barrero, Noam I. Libeskind, Yehuda Hoffman, Alexander Knebe, Jenny G. Sorce, Matthias Steinmetz, Elmo Tempel
Summary: Ultradiffuse galaxies (UDGs) are difficult to detect due to their low surface brightness, but they are important for studying cosmological models and galaxy formation. Previous studies have found a small number of UDGs in the Local Group, but it is unclear if this is expected. Using hydrodynamic simulations, we predict that there are around 12 isolated UDGs in the Local Group, of which 2 are detectable in the Sloan Digital Sky Survey. Future all-sky surveys could potentially reveal a larger population of UDGs in the Local Group.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Astronomy & Astrophysics
Finn A. Roper, Kyle A. Oman, Carlos S. Frenk, Alejandro Benitez-Llambay, Julio F. Navarro, Isabel M. E. Santos-Santos
Summary: We use cosmological hydrodynamical simulations to study the kinematics of gaseous discs in late-type dwarf galaxies. By creating high-resolution 'observations' of simulated dwarfs, we investigate the effect of different galaxy formation models on the rotation curves. We find that systematic discrepancies between the recovered rotation curve and the actual circular velocity curve arise due to non-circular gas orbits, finite thickness of gaseous discs, and departures from dynamical equilibrium.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Ana Contreras-Santos, Alexander Knebe, Weiguang Cui, Roan Haggar, Frazer Pearce, Meghan Gray, Marco De Petris, Gustavo Yepes
Summary: Using the data from THE THREE HUNDRED project, this study investigates galaxy pairs in high-density environments and explores the effectiveness of observational techniques and machine learning in identifying true pairs. The results show that the specific thresholds used to find pairs significantly affect the purity and completeness of the sample. By training a machine learning model, the study improves the accuracy and completeness of identifying true pairs and identifies important properties for distinguishing them.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Evgenii Chaikin, Joop Schaye, Matthieu Schaller, Alejandro Benitez-Llambay, Folkert S. J. Nobels, Sylvia Ploeckinger
Summary: We propose a subgrid model for supernova feedback in cosmological simulations of galaxy formation with a cold interstellar medium (ISM). The model uses thermal and kinetic channels of energy injection, based on the stochastic kinetic and thermal models for stellar feedback used in the owls and eagle simulations, respectively. By testing the model on simulations of Milky Way-mass and dwarf galaxies, we find that the combined use of thermal and kinetic channels produces smooth star formation histories, realistic galactic winds, and spatially resolved star formation rates and velocity dispersions that match observations. Varying the numerical resolution reveals excellent convergence of global star formation rates and wind mass loading.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Massimo Meneghetti, Weiguang Cui, Elena Rasia, Gustavo Yepes, Ana Acebron, Giuseppe Angora, Pietro Bergamini, Stefano Borgani, Francesco Calura, Giulia Despali, Carlo Giocoli, Giovanni Granata, Claudio Grillo, Alexander Knebe, Andrea V. Maccio, Amata Mercurio, Lauro Moscardini, Priyamvada Natarajan, Antonio Ragagnin, Piero Rosati, Eros Vanzella
Summary: Previous studies have found an excess in the estimated probability of galaxy-galaxy strong lensing in observed galaxy clusters compared to the theoretical predictions. In this study, the researchers analyzed a larger set of simulated galaxy clusters and investigated how different implementations of star formation and feedback in simulations affect the theoretical expectations. The results show that the probability for galaxy-galaxy strong lensing is higher in simulations with denser stellar cores, but the discrepancy with observations still persists.
ASTRONOMY & ASTROPHYSICS
(2023)
