Search Publications
The Pristine Inner Galaxy Survey - VIII. Characterizing the orbital properties of the ancient, very metal-poor inner Milky Way
Lewis, Geraint F.; Belokurov, Vasily; Buder, Sven +19 more
The oldest stars in the Milky Way (born in the first few billion years) are expected to have a high density in the inner few kpc, spatially overlapping with the Galactic bulge. We use spectroscopic data from the Pristine Inner Galaxy Survey (PIGS) to study the dynamical properties of ancient, metal-poor inner Galaxy stars. We compute distances usi…
On the existence of a very metal-poor disc in the Milky Way
Belokurov, Vasily; Ardern-Arentsen, Anke; Zhang, Hanyuan
The question of whether the Milky Way's disc extends to low metallicity has been the subject of debate for many years. We aim to address the question by employing a large sample of giant stars with radial velocities and homogeneous metallicities based on the Gaia Data Release 3 BP/RP(XP) spectra. We study the 3D velocity distribution of stars in v…
JWST/CEERS sheds light on dusty star-forming galaxies: Forming bulges, lopsidedness, and outside-in quenching at cosmic noon
Papovich, Casey; Finkelstein, Steven L.; Pérez-González, Pablo G. +26 more
Context. We investigate the morphology and resolved physical properties of a sample of 22 IR-selected dusty star-forming galaxies at cosmic noon using the James Webb Space Telescope NIRCam images obtained in the EGS field for the CEERS survey. The exceptional resolution of the NIRCam images allowed us to spatially resolve these galaxies up to 4.4 …
A NICER View of PSR J1231‑1411: A Complex Case
Bogdanov, Slavko; Salmi, Tuomo; Deneva, Julia S. +16 more
Recent constraints on neutron star mass and radius have advanced our understanding of the equation of state (EOS) of cold dense matter. Some of them have been obtained by modeling the pulses of three millisecond X-ray pulsars observed by the Neutron Star Interior Composition Explorer (NICER). Here, we present a Bayesian parameter inference for a f…
Validation of Elemental and Isotopic Abundances in Late-M Spectral Types with the Benchmark HIP 55507 AB System
Zhang, Yapeng; Do Ó, Clarissa R.; Fitzgerald, Michael P. +48 more
M dwarfs are common host stars to exoplanets but often lack atmospheric abundance measurements. Late-M dwarfs are also good analogs to the youngest substellar companions, which share similar T eff ∼ 2300–2800 K. We present atmospheric analyses for the M7.5 companion HIP 55507 B and its K6V primary star with Keck/KPIC high-resolution (R …
Overmassive Black Holes at Cosmic Noon: Linking the Local and the High-redshift Universe
Natarajan, Priyamvada; Siudek, Malgorzata; Pacucci, Fabio +2 more
We report for the first time a sample of 12 supermassive black holes (SMBHs) hosted by low-mass galaxies at cosmic noon, i.e., in a redshift range consistent with the peak of star formation history: z ∼ 1–3. These black holes are 2 orders of magnitude too massive for the stellar content of their hosts when compared with the local relation for acti…
JWST Reveals a Surprisingly High Fraction of Galaxies Being Spiral-like at 0.5 ≤ z ≤ 4
Guo, Yicheng; Martin, Alec; Kuhn, Vicki +3 more
Spiral arms are one of the most important features used to classify the morphology of local galaxies. The cosmic epoch when spiral arms first appeared contains essential clues to the evolution of disk galaxies. In this Letter, we used James Webb Space Telescope images from the Cosmic Evolution Early Release Science Survey to visually identify spir…
Lyα emission in galaxies at z ≃ 5-6: new insight from JWST into the statistical distributions of Lyα properties at the end of reionization
Charlot, Stéphane; Chevallard, Jacopo; Maseda, Michael V. +22 more
JWST has recently sparked a new era of Lyα spectroscopy, delivering the first measurements of the Lyα escape fraction and velocity profile in typical galaxies at z ≃ 6-10. These observations offer new prospects for insight into the earliest stages of reionization. But to realize this potential, we need robust models of Lyα properties in galaxies a…
JWST Photometric Time-delay and Magnification Measurements for the Triply Imaged Type Ia "SN H0pe" at z = 1.78
Pérez-Fournon, I.; Fox, O. D.; Ryan, R. E. +60 more
Supernova (SN) SN H0pe is a gravitationally lensed, triply imaged, Type Ia SN (SN Ia) discovered in James Webb Space Telescope imaging of the PLCK G165.7+67.0 cluster of galaxies. Well-observed multiply imaged SNe provide a rare opportunity to constrain the Hubble constant (H 0), by measuring the relative time delay between the images a…
JWST Transmission Spectroscopy of HD 209458b: A Supersolar Metallicity, a Very Low C/O, and No Evidence of CH4, HCN, or C2H2
Bean, Jacob L.; Zhang, Michael; Welbanks, Luis +3 more
We present the transmission spectrum of the original transiting hot Jupiter HD 209458b from 2.3 to 5.1 µm as observed with the NIRCam instrument on the James Webb Space Telescope (JWST). Previous studies of HD 209458b's atmosphere have given conflicting results on the abundance of H2O and the presence of carbon- and nitrogen-beari…