Search Publications
The Molecular Composition of Shadowed Proto-solar Disk Midplanes Beyond the Water Snowline
Walsh, Catherine; Nomura, Hideko; Ohno, Kazumasa +3 more
The disk midplane temperature is potentially affected by the dust traps/rings. The dust depletion beyond the water snowline will cast a shadow. In this study, we adopt a detailed gas-grain chemical reaction network, and investigate the radial gas and ice abundance distributions of dominant carbon-, oxygen-, and nitrogen-bearing molecules in disks …
Concordance between Observations and Simulations in the Evolution of the Mass Relation between Supermassive Black Holes and Their Host Galaxies
Treu, Tommaso; Bhowmick, Aklant K.; Blecha, Laura +7 more
We carry out a comparative analysis of the relation between the mass of supermassive black holes (BHs) and the stellar mass of their host galaxies at 0.2 < z < 1.7 using well-matched observations and multiple state-of-the-art simulations (e.g., MassiveBlackII, Horizon-AGN, Illustris, TNG, and a semianalytic model). The observed sample consis…
Searching for Compact Objects in Binaries with Gaia DR3
Liu, Jifeng; Gu, Wei-Min; Yi, Tuan +4 more
We search for compact objects in binaries based on Gaia DR3. A sample of 10 targets is derived under the following conditions: the radial velocity variable, low temperature (T eff < 6000 K), high mass function (f(M 2) > 1M ⊙), and ellipsoidal-like light curves. Two targets have LAMOST spectroscopic observatio…
Observationally Constraining the Starspot Properties of Magnetically Active M67 Sub-subgiant S1063
Tofflemire, Benjamin M.; Gully-Santiago, Michael A.; Gosnell, Natalie M. +1 more
Our understanding of the impact of magnetic activity on stellar evolution continues to unfold. This impact is seen in sub-subgiant stars, defined to be stars that sit below the subgiant branch and red of the main sequence in a cluster color-magnitude diagram. Here we focus on S1063, a prototypical sub-subgiant in open cluster M67. We use a novel t…
Improving White Dwarfs as Chronometers with Gaia Parallaxes and Spectroscopic Metallicities
Fouesneau, Morgan; El-Badry, Kareem; Bailer-Jones, Coryn A. L. +9 more
White dwarfs (WDs) offer unrealized potential in solving two problems in astrophysics: stellar age accuracy and precision. WD cooling ages can be inferred from surface temperatures and radii, which can be constrained with precision by high-quality photometry and parallaxes. Accurate and precise Gaia parallaxes along with photometric surveys provid…
Compton-thick AGN in the NuSTAR Era. IX. A Joint NuSTAR and XMM-Newton Analysis of Four Local AGN
Cusumano, G.; Ajello, M.; La Parola, V. +7 more
We present the results of the broadband X-ray spectral analysis of simultaneous NuSTAR and XMM-Newton observations of four nearby Compton-thick active galactic nuclei (AGN) candidates selected from the Swift Burst Alert Telescope 150 month catalog. This work is part of a larger effort to identify and characterize all Compton-thick (N H …
Exploring Changes in Quasar Spectral Energy Distributions across C IV Parameter Space
Gallagher, Sarah C.; Richards, Gordon T.; Shemmer, Ohad +4 more
We examine the UV/X-ray properties of 1378 quasars in order to link empirical correlations to theoretical models of the physical mechanisms dominating quasars as a function of mass and accretion rate. The clarity of these correlations is improved when (1) using C IV broad emission line equivalent width (EQW) and blueshift (relative to systemic) va…
The Obscured Fraction of Quasars at Cosmic Noon
Sawicki, Marcin; Schramm, Malte; Gwyn, Stephen +6 more
Statistical studies of X-ray selected active galactic nuclei (AGN) indicate that the fraction of obscured AGN increases with increasing redshift, and the results suggest that a significant part of the accretion growth occurs behind obscuring material in the early universe. We investigate the obscured fraction of highly accreting X-ray AGN at aroun…
The Relation between the Mass Accretion Rate and the Disk Mass in Class I Protostars
Kóspál, Ágnes; Fiorellino, Eleonora; Cruz-Sáenz de Miera, Fernando +5 more
Evidence of a relation between the mass accretion rate and the disk mass is established for young, Class II pre-main-sequence stars. This observational result opened an avenue to test theoretical models and constrain the initial conditions of disk formation, fundamental in the understanding of the emergence of planetary systems. However, it is bec…
K2 Photometry on Oscillation Mode Variability: The New Pulsating Hot B Subdwarf Star EPIC 220422705
Ma, Xiao-Yu; Zong, Weikai; Fu, Jian-Ning +4 more
We present an analysis of oscillation mode variability in the hot B subdwarf star EPIC 220422705, a new pulsator discovered from ~78 days of K2 photometry. The high-quality light curves provide a detection of 66 significant independent frequencies, from which we identified nine incomplete potential triplets and three quintuplets. Those g- and p-mu…