Search Publications
Stellar Mergers or Truly Young? Intermediate-age Stars on Highly Radial Orbits in the Milky Way's Stellar Halo
Price-Whelan, Adrian M.; Ness, Melissa K.; Horta, Danny +2 more
Reconstructing the mass assembly history of the Milky Way relies on obtaining detailed measurements of the properties of many stars in the galaxy, especially in the stellar halo. One of the most constraining quantities is stellar age, as it can shed light on the accretion time and quenching of star formation in merging satellites. However, obtaini…
EMPRESS. XIV. Strong High-ionization Lines of Young Galaxies at z = 0–8: Ionizing Spectra Consistent with the Intermediate-mass Black Holes with M BH ∼ 103–106 M ⊙
Ono, Yoshiaki; Ouchi, Masami; Harikane, Yuichi +16 more
We present ionizing spectra estimated at 13.6–100 eV for 10 dwarf galaxies with strong high-ionization lines of He II λ4686 and [Ne V] λ3426 ([Ne IV] λ2424) at z = 0 (z = 8) that are identified in our Keck/LRIS spectroscopy and the literature (the JWST Early Release Observations program). With the flux ratios of these high-ionization lines and >…
The TRGB-SBF Project. I. A Tip of the Red Giant Branch Distance to the Fornax Cluster with JWST
Anand, Gagandeep S.; Blakeslee, John P.; Tully, R. Brent +7 more
Differences between the local value of the Hubble constant measured via the distance ladder versus the value inferred from the cosmic microwave background with the assumption of the standard ΛCDM model have reached over 5σ significance. To determine if this discrepancy is due to new physics or more mundane systematic errors, it is essential to rem…
Delayed X-Ray Brightening Accompanied by Variable Ionized Absorption Following a Tidal Disruption Event
Yao, Y.; Wevers, T.; Tombesi, F. +4 more
Supermassive black holes can experience super-Eddington peak mass fallback rates following the tidal disruption of a star. The theoretical expectation is that part of the infalling material is expelled by means of an accretion disk wind, whose observational signature includes blueshifted absorption lines of highly ionized species in X-ray spectra.…
Searching for electromagnetic emission in an AGN from the gravitational wave binary black hole merger candidate S230922g
Valdes, Francisco; Andreoni, Igor; Graham, Matthew J. +18 more
We carried out long-term monitoring of the LIGO/Virgo/KAGRA binary black hole (BBH) merger candidate S230922g in search of electromagnetic emission from the interaction of the merger remnant with an embedding active galactic nuclei (AGN) accretion disk. Using a dataset primarily composed of wide-field imaging from the Dark Energy Camera and supple…
New Insights on the Accretion Properties of Class 0 Protostars from 2 µm Spectroscopy
Le Gouellec, Valentin J. M.; Hillenbrand, Lynne A.; Greene, Thomas P. +1 more
Sun-like stars are thought to accrete most of their final mass during the protostellar phase, during which the stellar embryo is surrounded by an infalling dense envelope. We present an analysis of 26 K-band spectra of Class 0 protostars, which are the youngest protostars. Of these, 18 are new observations made with the Keck MOSFIRE instrument. H …
Quantifying the Tension between Cosmological Models and JWST Red Candidate Massive Galaxies
Wang, Jun-Chao; Huang, Zhi-Qi; Huang, Lu +1 more
We develop a Python tool to estimate the tail distribution of the number of dark matter halos beyond a mass threshold and in a given volume in a light-cone. The code is based on the extended Press–Schechter model and is computationally efficient, typically taking a few seconds on a personal laptop for a given set of cosmological parameters. The hi…
Quantifying the Escape of Lyα at z ≈ 5–6: A Census of Lyα Escape Fraction with Hα-emitting Galaxies Spectroscopically Confirmed by JWST and VLT/MUSE
Chevallard, Jacopo; Fan, Xiaohui; Jiang, Linhua +11 more
The James Webb Space Telescope provides an unprecedented opportunity for unbiased surveys of Hα-emitting galaxies at z > 4 with the NIRCam's wide-field slitless spectroscopy (WFSS). In this work, we present a census of Lyα escape fraction (f esc,Lyα ) of 165 star-forming galaxies at z = 4.9–6.3, utilizing their Hα emission directly m…
A near-infrared variability survey of young planetary-mass objects
Henning, Thomas; Manjavacas, Elena; Schlieder, Joshua +12 more
We present a photometric variability survey of young planetary-mass objects using the New Technology Telescope in the JS and KS bands. Surface gravity plays an important role in the atmospheric structure of brown dwarfs, as young low-gravity L dwarfs have a higher variability rate than field L dwarfs. In this study, we extend…
The SPHERE view of the Chamaeleon I star-forming region. The full census of planet-forming disks with GTO and DESTINYS programs
Pinte, C.; Rab, C.; Schmidt, T. O. B. +32 more
Context. The past few years have seen a revolution in the study of circumstellar disks. New instrumentation in the near-infrared and (sub)millimeter regimes have allowed us to routinely spatially resolve disks around young stars of nearby star-forming regions. As a result, we have found that substructures with scales of ~10 au in disks are common.…