Search Publications
A magnetic massive star has experienced a stellar merger
Smoker, J. V.; Shenar, T.; Sana, H. +13 more
Massive stars (those ≥8 solar masses at formation) have radiative envelopes that cannot sustain a dynamo, the mechanism that produces magnetic fields in lower-mass stars. Despite this, approximately 7% of massive stars have observed magnetic fields, the origin of which is debated. We used multi-epoch interferometric and spectroscopic observations …
Achievement of the Planetary Defense Investigations of the Double Asteroid Redirection Test (DART) Mission
Buratti, Bonnie J.; Kolokolova, Ludmilla; Zinzi, Angelo +126 more
NASA's Double Asteroid Redirection Test (DART) mission was the first to demonstrate asteroid deflection, and the mission's Level 1 requirements guided its planetary defense investigations. Here, we summarize DART's achievement of those requirements. On 2022 September 26, the DART spacecraft impacted Dimorphos, the secondary member of the Didymos n…
Constraining primordial non-Gaussianity from DESI quasar targets and Planck CMB lensing
Miquel, Ramon; Font-Ribera, Andreu; Yèche, Christophe +33 more
We detect the cross-correlation between 2.7 million DESI quasar targets across 14,700 deg2 (180 quasars deg-2) and Planck 2018 CMB lensing at ∼30σ. We use the cross-correlation on very large scales to constrain local primordial non-Gaussianity via the scale dependence of quasar bias. The DESI quasar targets lie at an effectiv…
Initial-final mass relation from white dwarfs within 40 pc
Tremblay, Pier-Emmanuel; Cunningham, Tim; W. O'Brien, Mairi
We present an initial-final mass relation derived from the spectroscopically complete volume-limited 40 pc sample of white dwarfs. The relation is modelled using population synthesis methods to derive an initial stellar population which can be fit to the observed mass distribution of white dwarfs. The population synthesis accounts for binary evolu…
Apache Point Observatory (APO)/SMARTS Flare Star Campaign Observations. I. Blue Wing Asymmetries in Chromospheric Lines during Mid-M-Dwarf Flares from Simultaneous Spectroscopic and Photometric Observation Data
Hamaguchi, Kenji; Notsu, Yuta; Kowalski, Adam F. +12 more
We conducted the time-resolved simultaneous optical spectroscopic and photometric observations of mid-M-dwarf flare stars YZ CMi, EV Lac, and AD Leo. Spectroscopic observations were obtained using Apache Point Observatory 3.5 m and Small and Moderate Aperture Research Telescope System 1.5 m telescopes during 31 nights. Among the 41 detected flares…
Resolved Measurements of the CO-to-H2 Conversion Factor in 37 Nearby Galaxies
Sandstrom, Karin M.; Bolatto, Alberto D.; Leroy, Adam K. +6 more
We measure the CO-to-H2 conversion factor (α CO) in 37 galaxies at 2 kpc resolution, using the dust surface density inferred from far-infrared emission as a tracer of the gas surface density and assuming a constant dust-to-metal ratio. In total, we have ∼790 and ∼610 independent measurements of α CO for CO (2–1) an…
Radial halo substructure in harmony with the Galactic bar
Belokurov, Vasily; Evans, N. Wyn; Dillamore, Adam M.
Overdensities in the radial phase space $(r,v_{\rm r})$ of the Milky Way's halo have previously been associated with the phase-mixed debris of a highly radial merger event such as Gaia Sausage-Enceladus. We present and test an alternative theory in which the overdense 'chevrons' are instead composed of stars trapped in resonances with the Galactic…
Statistics for Galaxy Outflows at z ∼ 6–9 with Imaging and Spectroscopic Signatures Identified with JWST/NIRCam and NIRSpec Data
Ono, Yoshiaki; Ouchi, Masami; Harikane, Yuichi +5 more
We present statistics of z ∼ 6–9 galaxy outflows indicated by spatially extended gas emission and broad lines. With a total of 61 spectroscopically confirmed galaxies at z ∼ 6–9 in the JWST CEERS, GLASS, and ERO data, we find four galaxies with [O III] + Hβ ionized gas emission significantly extended beyond the kiloparsec-scale stellar components …
The GAPS programme at TNG. XLIX. TOI-5398, the youngest compact multi-planet system composed of an inner sub-Neptune and an outer warm Saturn
Baratella, M.; Pallé, E.; Scandariato, G. +68 more
Context. Short-period giant planets (P ≲ 10 days, Mp >0.1 MJ) are frequently found to be solitary compared to other classes of exo-planets. Small inner companions to giant planets with P ≲ 15 days are known only in five compact systems: WASP-47, Kepler-730, WASP-132, TOI-1130, and TOI-2000. Here, we report the confirmation…
Shallower radius valley around low-mass hosts: evidence for icy planets, collisions, or high-energy radiation scatter
Owen, James E.; Van Eylen, Vincent; Schlichting, Hilke E. +2 more
The radius valley, i.e. a dearth of planets with radii between 1.5 and 2 Earth radii, provides insights into planetary formation and evolution. Using homogenously revised planetary parameters from Kepler 1-min short cadence light curves, we remodel transits of 72 small planets mostly orbiting low-mass stars, improving the precision and accuracy of…