Search Publications
An updated measurement of the Hubble constant from near-infrared observations of Type Ia supernovae
Leibundgut, B.; Galbany, L.; Dhawan, S. +12 more
We present a measurement of the Hubble constant (H0) using type Ia supernovae (SNe Ia) in the near-infrared (NIR) from the recently updated sample of SNe Ia in nearby galaxies with distances measured via Cepheid period-luminosity relations by the SH0ES project. We collected public near-infrared photometry of up to 19 calibrator SNe Ia a…
First Results from the JWST Early Release Science Program Q3D: Ionization Cone, Clumpy Star Formation, and Shocks in a z = 3 Extremely Red Quasar Host
Johnson, Sean D.; Lützgendorf, Nora; Hamann, Fred +25 more
Massive galaxies formed most actively at redshifts z = 1-3 during the period known as "cosmic noon." Here we present an emission-line study of the extremely red quasar SDSSJ165202.64+172852.3's host galaxy at z = 2.94, based on observations with the Near Infrared Spectrograph integral field unit on board JWST. We use standard emission-line diagnos…
Wide Binaries from GAIA EDR3: preference for GR over MOND?
Sutherland, Will; Pittordis, Charalambos
Several recent studies have shown that velocity differences of very wide binary stars, measured to high precision with GAIA, can potentially provide an interesting test for modified-gravity theories which attempt to emulate dark matter. These systems should be entirely Newtonian according to standard dark-matter theories, while the predictions for…
Local stellar formation history from the 40 pc white dwarf sample
Tremblay, P. -E.; McCleery, J.; Cukanovaite, E. +4 more
We derive the local stellar formation history from the Gaia-defined 40 pc white dwarf sample. This is currently the largest volume-complete sample of white dwarfs for which spectroscopy is available, allowing for classification of the chemical abundances at the photosphere, and subsequently accurate determination of the atmospheric parameters. We …
Spectroscopic Time-series Performance of JWST/NIRSpec from Commissioning Observations
Nikolov, Nikolay; Sing, David K.; Böker, Torsten +22 more
We report on James Webb Space Telescope (JWST) commissioning observations of the transiting exoplanet HAT-P-14 b, obtained using the Bright Object Time Series (BOTS) mode of the NIRSpec instrument with the G395H/F290LP grating/filter combination (3-5 µm). While the data were used primarily to verify that the NIRSpec BOTS mode is working as e…
The impact of early massive mergers on the chemical evolution of Milky Way-like galaxies: insights from NIHAO-UHD simulations
Buck, Tobias; Minchev, Ivan; Macciò, Andrea V. +3 more
Recent observations of the Milky Way (MW) found an unexpected steepening of the star-forming gas metallicity gradient around the time of the Gaia-Sausage-Enceladus (GSE) merger event. Here, we investigate the influence of early (tmerger ≲ 5 Gyr) massive ($M_{\rm {gas}}^{\rm {merger}}/M_{\rm {gas}}^{\rm {main}}(t_{\rm {merger}})\gtrsim 1…
CEERS MIRI Imaging: Data Reduction and Quality Assessment
Yung, L. Y. Aaron; Kartaltepe, J. S.; Dickinson, M. +35 more
The Cosmic Evolution Early Release Science Survey (CEERS), targeting the Extended Groth Strip extragalactic field, is one of the James Webb Space Telescope Director's Discretionary Early Release Science programs. To date, all observations have been executed and include NIRCam/MIRI imaging and NIRSpec/NIRCam spectroscopic exposures. Here we discuss…
A massive helium star with a sufficiently strong magnetic field to form a magnetar
Wade, Gregg A.; Toonen, Silvia; Sana, Hugues +13 more
Magnetars are highly magnetized neutron stars, the formation mechanism of which is unknown. Hot helium-rich stars with spectra dominated by emission lines are known as Wolf-Rayet stars. We observed the binary system HD 45166 using spectropolarimetry and reanalyzed its orbit using archival data. We found that the system contains a Wolf-Rayet star w…
A state-of-the-art strong-lensing model of MACS J0416.1−2403 with the largest sample of spectroscopic multiple images
Grillo, C.; Rosati, P.; Vanzella, E. +9 more
The combination of multi-band imaging from the Hubble Space Telescope with Multi-Unit Spectroscopic Explorer integral field spectroscopy, obtained at the Very Large Telescope, has recently driven remarkable progress in strong-lensing (SL) modeling of galaxy clusters. From a few tens of multiple images with photometric redshifts per cluster, a new …
Clues on the presence and segregation of very massive stars in the Sunburst Lyman-continuum cluster at z = 2.37
Schaerer, D.; Martins, F.; Marques-Chaves, R. +15 more
We report the identification of very massive stars (VMS; mass > 100 M⊙) that may be segregated in the center of the young massive star cluster at z = 2.37 hosted in the lensed galaxy called Sunburst galaxy. This result is based on two pieces of evidence: (1) VLT/MUSE spectra of several multiple images of the same star cluster show ke…