Search Publications
The VISCACHA survey - IV. The SMC West Halo in 8D
Minniti, D.; Geisler, D.; Bica, E. +18 more
The structure of the Small Magellanic Cloud (SMC) is very complex, in particular in the periphery that suffers more from the interactions with the Large Magellanic Cloud (LMC). A wealth of observational evidence has been accumulated revealing tidal tails and bridges made up of gas, stars, and star clusters. Nevertheless, a full picture of the SMC …
The Local Stellar Halo is Not Dominated by a Single Radial Merger Event
Kim, Bokyoung; Lépine, Sebastien; Newberg, Heidi Jo +1 more
We use halo dwarf stars with photometrically determined metallicities that are located within 2 kpc of the Sun to identify local halo substructure. The kinematic properties of these stars do not indicate a single, dominant radial merger event (RME). The retrograde Virgo Radial Merger (VRM) component has [Fe/H] = -1.7. A second, nonrotating RME com…
RESOLVE and ECO: Finding Low-metallicity z 0 Dwarf AGN Candidates Using Optimized Emission-line Diagnostics
Moffett, Amanda J.; Kannappan, Sheila J.; Norris, Mark A. +6 more
Existing star-forming vs. active galactic nucleus (AGN) classification schemes using optical emission-line diagnostics mostly fail for low-metallicity and/or highly star-forming galaxies, missing AGN in typical z ~ 0 dwarfs. To recover AGN in dwarfs with strong emission lines (SELs), we present a classification scheme optimizing the use of existin…
Interferometric Detections of sdO Companions Orbiting Three Classical Be Stars
Gies, Douglas R.; Wang, Luqian; Klement, Robert +17 more
Classical Be stars are possible products of close binary evolution, in which the mass donor becomes a hot, stripped O- or B-type subdwarf (sdO/sdB), and the mass gainer spins up and grows a disk to become a Be star. While several Be+sdO binaries have been identified, dynamical masses and other fundamental parameters are available only for a single…
Substructure at High Speed. II. The Local Escape Velocity and Milky Way Mass with Gaia eDR3
Necib, Lina; Lin, Tongyan
Measuring the escape velocity of the Milky Way is critical in obtaining the mass of the Milky Way, understanding the dark matter velocity distribution, and building the dark matter density profile. In Necib & Lin, we introduced a strategy to robustly measure the escape velocity. Our approach takes into account the presence of kinematic substru…
Using AGN light curves to map accretion disc temperature fluctuations
Kochanek, C. S.; Neustadt, J. M. M.
We introduce a new model for understanding AGN continuum variability. We start from a Shakura-Sunyaev thin accretion disc with a steady-state radial temperature profile T(R) and assume that the variable flux is due to axisymmetric temperature perturbations δT(R, t). After linearizing the equations, we fit UV-optical AGN light curves to determine δ…
An Aligned Orbit for the Young Planet V1298 Tau b
Berlind, Perry; Calkins, Michael L.; Esquerdo, Gilbert A. +22 more
The alignment of planetary orbits with respect to the stellar rotation preserves information on their dynamical histories. Measuring this angle for young planets helps illuminate the mechanisms that create misaligned orbits for older planets, as different processes could operate over timescales ranging from a few megayears to a gigayear. We presen…
Survey of Ices toward Massive Young Stellar Objects. I. OCS, CO, OCN-, and CH3OH
Boogert, A. C. A.; Brewer, K.; Brittain, A. +1 more
An important tracer of the origin and evolution of cometary ices is the comparison with ices found in dense clouds and toward young stellar objects (YSOs). We present a survey of ices in the 2-5 µm spectra of 23 massive YSOs, taken with the NASA InfraRed Telescope Facility SpeX spectrometer. The 4.90 µm absorption band of OCS ice is de…
Quasars as high-redshift standard candles
Vignali, C.; Gilli, R.; Civano, F. +10 more
The non-linear relation between the X-ray and ultraviolet (UV) luminosity in quasars has been used to derive quasar distances and to build a Hubble diagram at redshifts up to z ∼ 7. This cosmological application is based on the assumption of independence of the relation on redshift and luminosity. We want to test the reliability of this hypothesis…
Dissecting Nearby Galaxies with piXedfit. I. Spatially Resolved Properties of Stars, Dust, and Gas as Revealed by Panchromatic SED Fitting
Tacchella, Sandro; Wu, Po-Feng; Morishita, Takahiro +5 more
We study spatially resolved properties (on spatial scales of ~1-2 kpc out to at least 3 effective radii) of the stars, dust, and gas in 10 nearby spiral galaxies. The properties of the stellar population and dust are derived by fitting the spatially resolved spectral energy distribution (SED) with more than 20 photometric bands ranging from far-ul…