Search Publications
Hot UV-bright stars of galactic globular clusters
Lanz, T.; Miller Bertolami, M. M.; Landsman, W. B. +1 more
Context. We have performed a census of the UV-bright population in 78 globular clusters using wide-field UV telescopes. This population includes a variety of phases of post-horizontal branch (HB) evolution, including hot post-asymptotic giant branch (AGB) stars, and post-early AGB stars. There are indications that old stellar systems like globular…
PLCK G165.7+67.0: Analysis of a Massive Lensing Cluster in a Hubble Space Telescope Census of Submillimeter Giant Arcs Selected Using Planck/Herschel
Donahue, Megan; Frye, Brenda L.; Conselice, Christopher J. +19 more
We present Hubble Space Telescope WFC3-IR imaging in the fields of six apparently bright dusty star-forming galaxies (DSFGs) at z = 2-4 identified by their rest-frame far-infrared colors using the Planck and Herschel space facilities. We detect near-infrared counterparts for all six submillimeter sources, allowing us to undertake strong-lensing an…
Surface refreshing of Martian moon Phobos by orbital eccentricity-driven grain motion
Fujimoto, Masaki; Ballouz, Ronald-Louis; Baresi, Nicola +2 more
The surface of the Martian moon Phobos exhibits two distinct geologic units, red and blue, characterized by their spectral slopes. The provenance of these units is uncertain yet crucial to understanding the origin of the Martian moon and its interaction with the space environment. Here we present a combination of dynamical analyses and numerical s…
ALMA observations of PKS 1549-79: a case of feeding and feedback in a young radio quasar
Morganti, Raffaella; Oosterloo, Tom; Tadhunter, Clive +4 more
We present CO(1-0) and CO(3-2) Atacama Large Millimeter/submillimeter Array observations of the molecular gas in PKS 1549-79, as well as mm and very long baseline interferometry 2.3-GHz continuum observations of its radio jet. PKS 1549-79 is one of the closest young, radio-loud quasars caught in an on-going merger in which the active galactic nucl…
How Much Information Does the Sodium Doublet Encode? Retrieval Analysis of Non-LTE Sodium Lines at Low and High Spectral Resolutions
Heng, Kevin; Fisher, Chloe
Motivated by both ground- and space-based detections of the sodium doublet in the transmission spectra of exoplanetary atmospheres, we revisit the theory and interpretation of sodium lines in non-local thermodynamic equilibrium (NLTE), where collisions are not efficient enough to maintain a Boltzmann distribution for the excited and ground states …
Analysis of colour and polarimetric variability of RW Aur A in 2010-2018
Grankin, K.; Shenavrin, V.; Safonov, B. +6 more
The results of UBVRIJHKLM photometry and VRI polarimetry of a young star RW Aur A observed during unprecedented long and deep (up to ΔV ≈ 5 mag) dimming events in 2010-11 and 2014-18 are presented. The polarization degree p of RW Aur A at this period has reached 30 per cent in the I band. As in the case of UX Ori-type stars (UXORs), the so-called …
Even-to-Odd Barium Isotope Ratio in Selected Galactic Halo Stars
Belyaev, A. K.; Mashonkina, L. I.
We have improved the Ba II model atom by taking into account the excitation of transitions through collisions with hydrogen atoms with the rate coefficients from the quantum-mechanical calculations of Belyaev and Yakovleva (2018). Using high-resolution spectra and Ba II line modeling when abandoning the assumption of LTE, we have determined the fr…
A Catalog of the Most Optically Luminous Galaxies at z < 0.3: Super Spirals, Super Lenticulars, Super Post-mergers, and Giant Ellipticals
Helou, George; Lanz, Lauranne; Mazzarella, Joseph +2 more
We present a catalog of the 1525 most optically luminous galaxies from the Sloan Digital Sky Survey with r-band luminosity L r > 8L* and redshift z < 0.3, including 84 super spirals, 15 super lenticulars, 14 super post-merger galaxies, and 1400 giant ellipticals. With mass in stars of 1011.3-1012 M ⊙
Detailed Chemical Composition and Orbit of the Newly Discovered Globular Cluster FSR 1758: Implications for the Accretion of the Sequoia Dwarf Galaxy onto the Milky Way
Minniti, Dante; Geisler, Doug; Villanova, Sandro +4 more
We present detailed chemical abundances, radial velocity, and orbital parameters for FSR 1758, a recently discovered massive cluster in the direction of the Galactic bulge. High-resolution (R ∼ 42,000) spectra were obtained for nine members using the Magellan/Clay telescope instrumented with the MIKE echelle spectrogragh in the wavelength range of…
The Virgo Overdensity Explained
Newberg, Heidi Jo; Donlon, Thomas, II; Weiss, Jake +2 more
We suggest that the Virgo Overdensity of stars in the stellar halo is the result of a radial dwarf galaxy merger that we call the Virgo Radial Merger. Because the dwarf galaxy passed very near to the Galactic center, the debris has a large range of energies but nearly zero L z angular momentum. The debris appears to extend from 5 to 5…