Search Publications
The Large Array Survey Telescope-Science Goals
Gal-Yam, A.; Rybicki, K.; Sadeh, I. +21 more
The Large Array Survey Telescope (LAST) is designed to survey the variable and transient sky at high temporal cadence. The array is comprised of 48 F/2.2 telescopes of 27.9 cm aperture, coupled to full-frame backside-illuminated cooled CMOS detectors with 3.76 µm pixels, resulting in a pixel scale of 1.″25. A single telescope with a field of…
Volatiles in the H2O and CO2 ices of comet 67P/Churyumov-Gerasimenko
De Keyser, Johan; Gombosi, Tamas I.; Berthelier, Jean-Jacques +11 more
European Space Agency's Rosetta spacecraft at comet 67P/Churyumov-Gerasimenko (67P) was the first mission that accompanied a comet over a substantial fraction of its orbit. On board was the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis mass spectrometer suite to measure the local densities of the volatile species sublimating from the i…
Measurement of the Angular Momenta of Pre-main-sequence Stars: Early Evolution of Slow and Fast Rotators and Empirical Constraints on Spin-down Torque Mechanisms
Stassun, Keivan G.; Kounkel, Marina; Hillenbrand, Lynne A. +3 more
We use TESS full-frame imaging data to investigate the angular momentum evolution of young stars in the Orion Complex. We confirm recent findings that stars with rotation periods faster than 2 days are overwhelmingly binaries, with typical separations of tens of au; such binaries quickly clear their disks, leading to a tendency for rapid rotators …
Automatic Classification of Galaxy Morphology: A Rotationally-invariant Supervised Machine-learning Method Based on the Unsupervised Machine-learning Data Set
Lin, Zesen; Kong, Xu; Gu, Yizhou +8 more
Classification of galaxy morphology is a challenging but meaningful task for the enormous amount of data produced by the next-generation telescope. By introducing the adaptive polar-coordinate transformation, we develop a rotationally-invariant supervised machine-learning (SML) method that ensures consistent classifications when rotating galaxy im…
Photometry and astrometry with JWST‑II: NIRCam distortion correction
Bedin, L. R.; Nardiello, D.; Griggio, M.
In preparation to make the most of our own planned James Webb Space Telescope investigations, we take advantage of publicly available calibration and early‑science observations to independently derive and test a geometric‑distortion solution for NIRCam detectors. Our solution is able to correct the distortion to better than 0.2 mas. Current data i…
Making waves in massive star asteroseismology
Bowman, Dominic M.
Massive stars play a major role not only in stellar evolution but also galactic evolution theory. This is because of their dynamical interaction with binary companions, but also because their strong winds and explosive deaths as supernovae provide chemical, radiative and kinematic feedback to their environments. Yet this feedback strongly depends …
Refined parameters of the HD 22946 planetary system and the true orbital period of planet d★
Alonso, R.; Deleuil, M.; Erikson, A. +85 more
Context. Multi-planet systems are important sources of information regarding the evolution of planets. However, the long-period planets in these systems often escape detection. These objects in particular may retain more of their primordial characteristics compared to close-in counterparts because of their increased distance from the host star. HD…
JWST's PEARLS: Dust Attenuation and Gravitational Lensing in the Backlit-galaxy System VV 191
Grogin, Norman A.; Hathi, Nimish P.; Koekemoer, Anton M. +28 more
We derive the spatial and wavelength behavior of dust attenuation in the multiple-armed spiral galaxy VV 191b using backlighting by the superimposed elliptical system VV 191a in a pair with an exceptionally favorable geometry for this measurement. Imaging using the James Webb Space Telescope and Hubble Space Telescope spans the wavelength range 0.…
The oblateness of the Milky Way dark matter halo from the stellar streams of NGC 3201, M68, and Palomar 5
Miralda-Escudé, Jordi; Palau, Carles G.
We explore constraints on the Milky Way dark matter halo oblateness using three stellar streams from globular clusters NGC3201, M68, and Palomar 5. Previous constraints on the gravitational potential from dynamical equilibrium of stellar populations and distant Milky Way satellites are included. We model the dark halo as axisymmetric with axis rat…
Three-dimensional modeling of Venus photochemistry and clouds
Stolzenbach, Aurélien; Lefèvre, Franck; Määttänen, Anni +1 more
We present here three-dimensional simulations of the Venus photochemistry and clouds from the ground to the bottom of the thermosphere. For that purpose, we have implemented a state-of-the-art photochemical and equilibrium cloud model in the Venus Planetary Climate Model (Venus PCM). The interactive coupling between dynamics, radiation, chemistry …