Publications (65)
Old-Aged Stellar Population Distance Indicators
Rachael L. Beaton, Giuseppe Bono, Vittorio Francesco Braga +8
Old-aged stellar distance indicators are present in all Galactic structures (halo, bulge, disk) and in galaxies of all Hubble types and, thus, are immensely powerful tools for unde…
On the early evolution of Local Group dwarf galaxy types: star formation and supernova feedback
Jose R. Bermejo-Climent, Giuseppina Battaglia, Carme Gallart +8
According to star formation histories (SFHs), Local Group dwarf galaxies can be broadly classified in two types: those forming most of their stars before () and t…
Metallicity of Galactic RR Lyrae from Optical and Infrared Light Curves: I. Period-Fourier-Metallicity Relations for Fundamental Mode RR Lyrae
Joseph P. Mullen, Massimo Marengo, Clara E. MartÃnez-Vázquez +12
We present newly-calibrated period--[Fe/H] relations for fundamental mode RR Lyrae stars in the optical and, for the first time, mid-infrared. This work's calibration data…
Classical Cepheids in the Galactic thin disk I. Abundance gradients via non-local thermodynamic equilibrium spectral analysis
Antonino Nunnari, Valentina D'Orazi, Giuliana Fiorentino +23
Classical Cepheids (CCs) have long been considered excellent tracers of the chemical evolution of the Milky Way's young disk. We present a homogeneous, NLTE spectroscopic analysis…
A DECam View of the Diffuse Dwarf Galaxy Crater II: Variable Stars
A. Katherina Vivas, Alistair R. Walker, Clara E. MartÃnez-Vázquez +11
Time series observations of a single dithered field centered on the diffuse dwarf satellite galaxy Crater II were obtained with the Dark Energy Camera (DECam) at the 4m Blanco Tele…
An old, metal-poor globular cluster in Sextans A and the metallicity floor of globular cluster systems
Michael A. Beasley, Ryan Leaman, Carme Gallart +4
We report the confirmation of an old, metal-poor globular cluster in the nearby dwarf irregular galaxy Sextans A, the first globular cluster known in this galaxy. The cluster, whic…
Proper Motions and Orbits of Distant Local Group Dwarf Galaxies from a combination of Gaia and Hubble Data
Paul Bennet, Ekta Patel, Sangmo Tony Sohn +12
We have determined the proper motions (PMs) of 12 dwarf galaxies in the Local Group (LG), ranging from the outer Milky Way (MW) halo to the edge of the LG. We used HST as the first…
Stellar photometry with Multi Conjugate Adaptive Optics
Giuliana Fiorentino, Davide Massari, Alan McConnachie +14
We overview the current status of photometric analyses of images collected with Multi Conjugate Adaptive Optics (MCAO) at 8-10m class telescopes that operated, or are operating, on…
The galaxy "missing dark matter" NGC1052-DF4 is undergoing tidal disruption
Mireia Montes, Raúl Infante-Sainz, Alberto Madrigal-Aguado +4
The existence of long-lived galaxies lacking dark matter represents a challenge to our understanding of how galaxies form. Here, we present evidence that explains the lack of dark…
RR Lyrae mid-infrared Period-Luminosity-Metallicity and Period-Wesenheit-Metallicity relations based on Gaia DR3 parallaxes
Joseph P. Mullen, Massimo Marengo, Clara E. MartÃnez-Vázquez +8
We present new empirical infrared Period-Luminosity-Metallicity (PLZ) and Period-Wesenheit-Metallicity (PWZ) relations for RR Lyrae based on the latest Gaia EDR3 parallaxes. The re…
Pegasus V -- a newly discovered ultra-faint dwarf galaxy on the outskirts of Andromeda
Michelle L. M. Collins, Emily J. E. Charles, David MartÃnez-Delgado +5
We report the discovery of an ultra-faint dwarf in the constellation of Pegasus. Pegasus~V (Peg~V) was initially identified in the public imaging data release of the DESI Legacy Im…
Horizontal branch morphology: A new photometric parametrization
Marianna Torelli, Giacinto Iannicola, Peter B. Stetson +8
Theory and observations indicate that the distribution of stars along the horizontal branch of Galactic globular clusters mainly depends on the metal content. However, the existenc…
MuSCAT2: four-color Simultaneous Camera for the 1.52-m Telescopio Carlos Sánchez
Norio Narita, Akihiko Fukui, Nobuhiko Kusakabe +19
We report the development of a 4-color simultaneous camera for the 1.52~m Telescopio Carlos Sánchez (TCS) in the Teide Observatory, Canaries, Spain. The new instrument, named MuSC…
The ACS LCID Project XI. On the early time resolution of LG dwarf galaxy SFHs: Comparing the effects of reionization in models with observations
Antonio Aparicio, Sebastian L. Hidalgo, Evan Skillman +10
The analysis of the early star formation history (SFH) of nearby galaxies, obtained from their resolved stellar populations is relevant as a test for cosmological models. However,…
On the missing second generation AGB stars in NGC6752
Santi Cassisi, Maurizio Salaris, Adriano Pietrinferni +2
[Abridged] In recent years the view of Galactic globular clusters as simple stellar populations has changed dramatically, as it is now thought that basically all GCs host multiple…
Andromeda XXXVI: discovery of a new ultra-faint dwarf galaxy towards M31
Joanna D. Sakowska, David MartÃnez-Delgado, Michelle L. M. Collins +4
We present deep imaging of Andromeda XXXVI (And XXXVI), a dwarf galaxy discovered through visual inspection of the Pan-Andromeda Archaeological Survey, using observations obtained…
The Second Data Release of the Survey of the MAgellanic Stellar History (SMASH)
David L. Nidever, Knut Olsen, Yumi Choi +32
The Large and Small Magellanic Clouds (LMC and SMC) are the largest satellite galaxies of the Milky Way and close enough to allow for a detailed exploration of their structure and…
Pisces VII: Discovery of a possible satellite of Messier 33 in the DESI Legacy Imaging Surveys
David Martinez-Delgado, Noushin Karim, Emily J. E. Charles +5
We report deep imaging observations with DOLoRes@TNG of an ultra-faint dwarf satellite candidate of the Triangulum galaxy (M33) found by visual inspection of the public imaging dat…
Proof that the Milky Way experienced a significant merger only 1.5 billion years after the Big Bang
Davide Massari, Chiara Zerbinati, Cristiano Fanelli +15
The merger history of the Galaxy has been traced back firmly to redshift 2 (10 Billion years ago). While there have been claims of the existence of at least one more significant me…
The GALAH survey: Tracing the Milky Way's formation and evolution through RR Lyrae stars
Valentina D'Orazi, Nicholas Storm, Andrew R. Casey +39
Stellar mergers and accretion events have been crucial in shaping the evolution of the Milky Way (MW). These events have been dynamically identified and chemically characterised us…
SMASH - Survey of the MAgellanic Stellar History
David L. Nidever, Knut Olsen, Alistair R. Walker +36
The Large and Small Magellanic Clouds (LMC and SMC) are unique local laboratories for studying the formation and evolution of small galaxies in exquisite detail. The Survey of the…
Pisces VII/Triangulum III -- M33's second dwarf satellite galaxy
Michelle L. M. Collins, Noushin Karim, David Martinez-Delgado +6
Pisces VII/Triangulum III (Pisc~VII) was discovered in the DESI Legacy Imaging Survey and was shown to be a Local Group dwarf galaxy with follow-up imaging from the 4-m Telescopio…
Cluster Ages to Reconstruct the Milky Way Assembly (CARMA) I. The final word on the origin of NGC6388 and NGC6441
Davide Massari, Fernando Aguado-Agelet, Matteo Monelli +11
We present CARMA, the Cluster Ages to Reconstruct the Milky Way Assembly project, that aims at determining precise and accurate age measurements for the entire system of known Gala…
The ISLAndS project II: The Lifetime Star Formation Histories of Six Andromeda dSphs
Evan D. Skillman, Matteo Monelli, Daniel R. Weisz +17
The Initial Star formation and Lifetimes of Andromeda Satellites (ISLAndS) project uses Hubble Space Telescope imaging to study a representative sample of six Andromeda dSph satell…
SMASHing THE LMC: Mapping a Ring-like Stellar Overdensity in the LMC Disk
Yumi Choi, David L. Nidever, Knut Olsen +18
We explore the stellar structure of the Large Magellanic Cloud (LMC) disk using data from the Survey of the MAgellanic Stellar History (SMASH) and the Dark Energy Survey. We detect…
The ACS LCID project. IX. Imprints of the early Universe in the radial variation of the star formation history of dwarf galaxies
Sebastian L. Hidalgo, Matteo Monelli, Antonio Aparicio +8
Based on Hubble Space Telescope observations from the Local Cosmology from Isolated Dwarfs project, we present the star formation histories, as a function of galactocentric radius,…
A distance of 13 Mpc resolves the claimed anomalies of the galaxy lacking dark matter
Ignacio Trujillo, Michael A. Beasley, Alejandro Borlaff +10
The claimed detection of a diffuse galaxy lacking dark matter represents a possible challenge to our understanding of the properties of these galaxies and galaxy formation in gener…
Period Change Similarities among the RR Lyrae Variables in Oosterhoff I and Oosterhoff II Globular Systems
Andrea Kunder, Alistair Walker, Peter B. Stetson +9
We present period change rates (dP/dt) for 42 RR Lyrae variables in the globular cluster IC4499. Despite clear evidence of these period increases or decreases, the observed per…
A disk and no signatures of tidal distortion in the galaxy "lacking" dark matter NGC 1052-DF2
Mireia Montes, Ignacio Trujillo, Raúl Infante-Sainz +2
Using ultra-deep imaging ( mag/arcsec; 3, 10"x10"), we probed the surroundings of the first galaxy "lacking" dark matter KKS2000[04] (NGC 1052-DF2). Signs of t…
Spatial dependence of the Star Formation History in the Central Regions of the Fornax Dwarf Spheroidal Galaxy
Andrés del Pino, Sebastian L. Hidalgo, Antonio Aparicio +5
We present the Star Formation History (SFH) and the age-metallicity relation (AMR) in three fields of the Fornax dwarf spheroidal galaxy. They sample a region spanning from the cen…
The ACS LCID Project: RR Lyrae stars as tracers of old population gradients in the isolated dwarf spheroidal galaxy Tucana
Edouard J. Bernard, Carme Gallart, Matteo Monelli +9
We present a study of the radial distribution of RR Lyrae variables, which present a range of photometric and pulsational properties, in the dwarf spheroidal galaxy Tucana. We find…
On the dwarf irregular galaxy NGC 6822. I. Young, intermediate and old stellar populations
Maria Tantalo, Massimo Dall'Ora, Giuseppe Bono +13
We present accurate and deep multi-band () photometry of the Local Group dwarf irregular galaxy NGC 6822. The images were collected with wide field cameras at 2m/4m- (INT,CT…
The ACS LCID project. V. The Star Formation History of the Dwarf Galaxy \objectname[]{LGS-3}: Clues for Cosmic Reionization and Feedback
Sebastian L. Hidalgo, Antonio Aparicio, Evan Skillman +11
We present an analysis of the star formation history (SFH) of the transition-type (dIrr/dSph) Local Group galaxy \objectname[]{LGS-3} (Pisces) based on deep photometry obtained wit…
Weak Galactic halo--dwarf spheroidal connection from RR Lyrae stars
Giuliana Fiorentino, Giuseppe Bono, Matteo Monelli +6
We discuss the role that dwarf galaxies may have played in the formation of the Galactic halo (Halo) using RR Lyrae stars (RRL) as tracers of their ancient stellar component. The c…
Hydra II: a faint and compact Milky Way dwarf galaxy found in the Survey of the Magellanic Stellar History
Nicolas F. Martin, David L. Nidever, Gurtina Besla +26
We present the discovery of a new dwarf galaxy, Hydra II, found serendipitously within the data from the ongoing Survey of the MAgellanic Stellar History (SMASH) conducted with the…
New theoretical Period-Luminosity-Metallicity relations for RR Lyrae in the Rubin-LSST filters
Marcella Marconi, Roberto Molinaro, Massimo Dall'Ora +8
The revolutionary power of future Rubin-LSST observations will allow us to significantly improve the physics of pulsating stars, including RR Lyrae. In this context, an updated the…
Exploring the Very Extended Low Surface Brightness Stellar Populations of the Large Magellanic Cloud with SMASH
David L. Nidever, Knut Olsen, Yumi Choi +23
We present the detection of very extended stellar populations around the Large Magellanic Cloud (LMC) out to R~21 degrees, or ~18.5 kpc at the LMC distance of 50 kpc, as detected i…
Dark halo structure in the Carina dwarf spheroidal galaxy: joint analysis of multiple stellar components
Kohei Hayashi, Michele Fabrizio, Ewa L. Åokas +4
Photometric and spectroscopic observations of the Carina dSph revealed that this galaxy contains two dominant stellar populations of different age and kinematics. The co-existence…
Homogeneous Photometry VI: Variable Stars in the Leo I Dwarf Spheroidal Galaxy
Peter B. Stetson, Giuliana Fiorentino, Giuseppe Bono +5
We have characterized the pulsation properties of 164 candidate RR Lyrae variables (RRLs) and 55 candidate Anomalous and/or short-period Cepheids in Leo I dwarf spheroidal galaxy.…
SMASHing the low surface brightness SMC
Pol Massana, Noelia E. D. Noël, David L. Nidever +22
The periphery of the Small Magellanic Cloud (SMC) can unlock important information regarding galaxy formation and evolution in interacting systems. Here, we present a detailed stud…
The dwarf irregular galaxy NGC 6822. II. Young, intermediate and old stellar populations: comparison between theory and observations
Maria Tantalo, Giuseppe Bono, Maurizio Salaris +14
This paper presents a quantitative analysis of the stellar content in the Local Group dwarf irregular galaxy NGC 6822 by comparing stellar evolution models and observations in colo…
The ISLANDS project I: Andromeda XVI, An Extremely Low Mass Galaxy not Quenched by Reionization
Matteo Monelli, Clara E. MartÃnez-Vázquez, Edouard J. Bernard +14
Based on data aquired in 13 orbits of HST time, we present a detailed evolutionary history of the M31 dSph satellite Andromeda XVI, including its life-time star formation history,…
A Photometric Study of Globular Clusters Observed by the APOGEE Survey
Szabolcs Mészáros, D. A. GarcÃa-Hernández, Santi Cassisi +8
In this paper we describe the photometric and spectroscopic properties of multiple populations in seven northern globular clusters. In this study we employ precise ground based pho…
The ACS LCID Project. VIII. The short-period Cepheids of Leo A
Edouard J. Bernard, Matteo Monelli, Carme Gallart +9
We present the results of a new search for variable stars in the Local Group dwarf galaxy Leo A, based on deep photometry from the Advanced Camera for Surveys onboard the Hubble Sp…
On the absolute age of the metal-rich globular M71 (NGC 6838): I. optical photometry
Alessandra Di Cecco, Giuseppe Bono, Pier Giorgio Prada Moroni +9
We investigated the absolute age of the Galactic globular cluster M71 (NGC 6838) by using optical ground-based images (u',g',r',i',z') collected with the MegaCam camera at the Cana…
Anomalous Cepheids in the Large Magellanic Cloud: Insight into their origin and connection with the star formation history
Giuliana Fiorentino, Matteo Monelli
Context. The properties of variable stars can give independent constraints on the star formation history of the host galaxy, by determining the age and metallicity of the parent po…
On the use of asymmetric PSF on NIR images of crowded stellar fields
Giuliana Fiorentino, Ivan Ferraro, Giacinto Iannicola +8
We present data collected using the camera PISCES coupled with the Firt Light Adaptive Optics (FLAO) mounted at the Large Binocular Telescope (LBT). The images were collected using…
The elderly among the oldest: new evidence for extremely metal-poor RR Lyrae stars
Valentina D'Orazi, Vittorio F. Braga, Giuseppe Bono +21
We performed a detailed spectroscopic analysis of three extremely metal-poor RR Lyrae stars, exploring uncharted territories at these low metallicities for this class of stars. Usi…
The ISLAnds Project III: Variable Stars in Six Andromeda Dwarf Spheroidal Galaxies
Clara E. MartÃnez-Vázquez, Matteo Monelli, Edouard J. Bernard +15
We present a census of variable stars in six M31 dwarf spheroidal satellites observed with the Hubble Space Telescope. We detect 870 RR Lyrae (RRL) stars in the fields of And I (29…
The birth of the Milky Way as uncovered by accurate stellar ages with Gaia
Carme Gallart, Edouard J. Bernard, Chris B. Brook +4
Knowledge of ages for stars formed over a galaxy's lifetime is fundamental to understand its formation and evolution. However, stellar ages are difficult to obtain since they canno…
The Star Formation History and Dust Content in the Far Outer Disc of M31
Edouard J. Bernard, Annette M. N. Ferguson, Michael K. Barker +7
We present a detailed analysis of two fields located 26 kpc (~5 scalelengths) from the centre of M31. One field samples the major axis populations--the Outer Disc field--while the…
Unveiling the purely young star formation history of the SMC's northeastern shell from colour-magnitude diagram fitting
Joanna D. Sakowska, Noelia E. D. Noël, Tomás Ruiz-Lara +12
We obtain a quantitative star formation history (SFH) of a shell-like structure ('shell') located in the northeastern part of the Small Magellanic Cloud (SMC). We use the Survey of…
Metallicity of Galactic RR Lyrae from Optical and Infrared Light Curves: II. Period-Fourier-Metallicity Relations for First Overtone RR Lyrae
Joseph P. Mullen, Massimo Marengo, Clara E. MartÃnez-Vázquez +11
We present new period--[Fe/H] relations for first overtone RRL stars (RRc), calibrated over a broad range of metallicities () utilizing the la…
Large Magellanic Cloud Globular Clusters in the Near-infrared. I. RR Lyrae in Reticulum
Anupam Bhardwaj, Susmita Das, Prashant Nishad +10
Reticulum is an old, metal-poor, and sparsely populated globular cluster in the outer regions of the Large Magellanic Cloud (LMC) and hosts a rich population of RR Lyrae stars. Bei…
Comparing M31 and Milky Way Satellites: The Extended Star Formation Histories of Andromeda II and Andromeda XVI
Daniel R. Weisz, Evan D. Skillman, Sebastian L. Hidalgo +16
We present the first comparison between the lifetime star formation histories (SFHs) of M31 and Milky Way (MW) satellites. Using the Advanced Camera for Surveys aboard the Hubble S…
The ACS LCID project. X. The Star Formation History of IC 1613: Revisiting the Over-Cooling Problem
Evan D. Skillman, Sebastian L. Hidalgo, Daniel R. Weisz +13
We present an analysis of the star formation history (SFH) of a field near the half light radius in the Local Group dwarf irregular galaxy IC 1613 based on deep Hubble Space Telesc…
Toward an internally consistent astronomical distance scale
Richard de Grijs, Frederic Courbin, Clara E. Martinez-Vazquez +3
Accurate astronomical distance determination is crucial for all fields in astrophysics, from Galactic to cosmological scales. Despite, or perhaps because of, significant efforts to…
Is Crater II disrupting?
A. Katherina Vivas, Alistair Walker, Clara MartÃnez-Vázquez +5
Crater~II (CraII) is a very intriguing, low-surface brightness and extended galaxy in the vicinity of our Milky Way. Motivated by its huge area and the number of RR Lyrae stars (RR…
The ACS LCID Project. II. Faint Variable Stars in the Isolated Dwarf Irregular Galaxy IC1613
Edouard J. Bernard, Matteo Monelli, Carme Gallart +6
(Abridged) We present the results of a new search for variable stars in the Local Group (LG) isolated dwarf galaxy IC1613, based on 24 orbits of F475W and F814W photometry from the…
On the magnitude difference between the main sequence turn off and the red giant branch bump in Galactic globular clusters
Santi Cassisi, Antonio Marin-Franch, Maurizio Salaris +3
We present new measurements of the magnitude of the main sequence turn off and the red giant branch bump in the luminosity function of a sample of Galactic globular clusters with u…
Chronology of our Galaxy from Gaia colour-magnitude diagram fitting (ChronoGal) -- III. Age and metallicity distribution of Gaia-Sausage-Enceladus stars near the Sun
Yllari K. González-Koda, Tomás Ruiz-Lara, Carme Gallart +14
Context. Gaia-Sausage-Enceladus is considered the last major merger that contributed to the formation of the Milky Way. Its remnants dominate the nearby accreted stellar halo of th…
Metallicities from high resolution spectra of 49 RR Lyrae Variables
Christina K. Gilligan, Brian Chaboyer, Massimo Marengo +12
Accurate metallicities of RR Lyrae are extremely important in constraining period-luminosity-metallicity relationships (PLZ), particularly in the near-infrared. We analyse 69 high-…
Cluster Ages to Reconstruct the Milky Way Assembly (CARMA). II. The age-metallicity relation of Gaia-Sausage-Enceladus globular clusters
Fernando Aguado-Agelet, Davide Massari, Matteo Monelli +8
We present the age determination of 13 globular clusters dynamically associated with the Gaia-Sausage-Enceladus (GSE) merger event, as part of the CARMA project effort to trace the…
The TRGB distance to the second galaxy "missing dark matter". Evidence for two groups of galaxies at 13.5 and 19 Mpc in the line of sight of NGC1052
Matteo Monelli, Ignacio Trujillo
A second galaxy ``missing dark matter" (NGC1052-DF4) has been recently reported. Here we show, using the location of the Tip of the Red Giant Branch (TRGB), that the distance to th…
The ACS LCID Project. I. Short-Period Variables in the Isolated Dwarf Spheroidal Galaxies Cetus & Tucana
Edouard J. Bernard, Matteo Monelli, Carme Gallart +9
(abridged) We present the first study of the variable star populations in the isolated dwarf spheroidal galaxies (dSph) Cetus and Tucana. Based on Hubble Space Telescope images obt…