A. Savino

JWST Observations of RR Lyrae in Leo P

Catherine M. Slaughter, Alessandro Savino, Meredith Durbin +5

We analyze co-spatial HST/ACS and JWST/NIRCam time-series photometric observations of RR Lyrae in the low-metallicity dwarf galaxy Leo P. This study provides a new opportunity to e…

Characterising the Globular Cluster Systems of Three Local Group Dwarf Galaxies: NGC6822, NGC147 and NGC185

Gracie McGill, Annette M. N. Ferguson, Dougal Mackey +8

We present deep HST photometry for 26 globular clusters (GCs) residing in three Local Group dwarf galaxies: the isolated dwarf irregular (dIrr) galaxy, NGC6822, and the M31 dwarf e…

Probing the IMF in the Early Universe -- Direct measurements in the Boötes I UFD with JWST/NIRCam

Keyi Ding, Mario Gennaro, Roberto J. Avila +20

The dependence of the stellar initial mass function (IMF) on star-formation environment, particularly at low metallicities and high redshifts, remains poorly constrained. Ultra-fai…

The Star Formation History of WLM from Asymptotic Giant Branch Stars and The Discovery of a Candidate Accreted System in its Outer Disk

Abigail J. Lee, Daniel R. Weisz, Andrew E. Dolphin +1

We measure the star formation history (SFH) of Local Group dwarf galaxy WLM using wide-area ( $\sim 4$ half-light radii) ground-based near-infrared (NIR) imaging of bright ($M_{J}<-4…

astro-ph.GA2025

Wide binaries in an ultra-faint dwarf galaxy: discovery, population modeling, and a nail in the coffin of primordial black hole dark matter

Cheyanne Shariat, Kareem El-Badry, Mario Gennaro +24

We report the discovery and characterization of a wide binary population in the ultrafaint dwarf galaxy Boötes I using deep JWST/NIRCam imaging. Our sample consists of 52 candidate…

astro-ph.GA2025★ 6 cited

Mass Modeling the Andromeda Dwarf Galaxies: Andromeda VI and Andromeda XXIII

Connor S. Pickett, Michelle L. M. Collins, R. Michael Rich +7

Accurately mapping the mass profiles of low mass dwarf spheroidal (dSph) galaxies allows us to test predictions made by dark matter (DM) models. To date, such analyses have primari…

astro-ph.GA2025

SN 2023ixf in the Pinwheel Galaxy M101: From Shock Breakout to the Nebular Phase

Weikang Zheng, Luc Dessart, Alexei V. Filippenko +39

We present photometric and spectroscopic observations of SN 2023ixf covering from day one to 442 days after explosion. SN 2023ixf reached a peak $V$ -band absolute magnitude of $-18…

astro-ph.GA2025

The JWST Resolved Stellar Populations Early Release Science Program. VIII. The Spatially Resolved Star Formation History of WLM

Roger E. Cohen, Kristen B. W. McQuinn, Alessandro Savino +17

We measure radial stellar age gradients in the relatively isolated gas-rich dwarf irregular WLM, combining JWST NIRCam and NIRISS imaging with six archival Hubble fields over semi-…

Measuring Star Formation Histories from Asymptotic Giant Branch Stars I: A Demonstration in M31

Abigail J. Lee, Daniel R. Weisz, Yi Ren +2

We demonstrate how near-infrared (NIR) imaging of resolved luminous asymptotic giant branch (AGB) stars can be used to measure well-constrained star formation histories (SFHs) acro…

Stellar Metallicities and Gradients in the Faint M31 Satellites Andromeda XVI and Andromeda XXVIII

Sal Wanying Fu, Daniel R. Weisz, Else Starkenburg +11

We present $\sim 300$ stellar metallicity measurements in two faint M31 dwarf galaxies, Andromeda XVI ( $M_{V} = - 7.5$ ) and Andromeda XXVIII ( $M_{V} = - 8.8$ ) derived using metallicity-se…

The JWST Resolved Stellar Populations Early Release Science Program VII. Stress Testing the NIRCam Exposure Time Calculator

A. Savino, M. Gennaro, A. E. Dolphin +19

We empirically assess estimates from v3.0 of the JWST NIRCam Exposure Time Calculator (ETC) using observations of resolved stars in Local Group targets taken as part of the Resolve…

The JWST Resolved Stellar Populations Early Release Science Program V. DOLPHOT Stellar Photometry for NIRCam and NIRISS

Daniel R. Weisz, Andrew E. Dolphin, Alessandro Savino +38

We present NIRCam and NIRISS modules for DOLPHOT, a widely-used crowded field stellar photometry package. We describe details of the modules including pixel masking, astrometric al…

The JWST Resolved Stellar Populations Early Release Science Program VI. Identifying Evolved Stars in Nearby Galaxies

Martha L. Boyer, Giada Pastorelli, Léo Girardi +20

We present an investigation of evolved stars in the nearby star-forming galaxy WLM, using NIRCam imaging from the JWST resolved stellar populations early-release science (ERS) prog…

The JWST Resolved Stellar Populations Early Release Science Program IV: The Star Formation History of the Local Group Galaxy WLM

Kristen. B. W. McQuinn, Max J. B. Newman, Alessandro Savino +23

We present the first star formation history (SFH) and age-metallicity relation (AMR) derived from resolved stellar populations imaged with the JWST NIRCam instrument. The target is…

Stellar Metallicities and Gradients in the Isolated, Quenched Low-Mass Galaxy Tucana

Sal Wanying Fu, Daniel R. Weisz, Else Starkenburg +10

We measure the metallicities of 374 red giant branch (RGB) stars in the isolated, quenched dwarf galaxy Tucana using Hubble Space Telescope (HST) narrow-band (F395N) Calcium H & K…

astro-ph.GA2023★ 34 cited

The Hubble Space Telescope Survey of M31 Satellite Galaxies. III. Calibrating the Horizontal Branch as an Age Indicator for Nearby Galaxies

Connor Jennings, Alessandro Savino, Daniel Weisz +14

We present a new method for measuring the mean age of old/intermediate stellar populations in resolved, metal-poor ( $⟨[Fe/H]⟩ ≲ - 1.5$ ) galaxies using only th…

astro-ph.GA2023★ 1 cited

Testing the near-far connection with FIRE simulations: inferring the stellar mass function of the proto-Local Group at z > 6 using the fossil record of present-day galaxies

Pratik J. Gandhi, Andrew Wetzel, Michael Boylan-Kolchin +6

The shape of the low-mass (faint) end of the galaxy stellar mass function (SMF) or ultraviolet luminosity function (UVLF) at z > 6 is an open question for understanding which galax…

Metallicity Distribution Functions of 13 Ultra-Faint Dwarf Galaxy Candidates from Hubble Space Telescope Narrowband Imaging

Sal Wanying Fu, Daniel R. Weisz, Else Starkenburg +10

We present uniformly measured stellar metallicities for 463 stars in 13 Milky Way (MW) ultra-faint dwarf galaxies (UFDs; $M_{V} = - 7.1$ to $- 0.8$ ) using narrowband CaHK (F395N) imagi…