Search Publications
Evidence for Disk Truncation at Low Accretion States of the Black Hole Binary MAXI J1820+070 Observed by NuSTAR and XMM-Newton
Fabian, Andrew C.; Walton, Dominic J.; Hare, Jeremy +3 more
We present results from NuSTAR and XMM-Newton observations of the new black hole X-ray binary MAXI J1820+070 at low accretion rates (below 1% of the Eddington luminosity). We detect a narrow Fe Kα emission line, in contrast to the broad and asymmetric Fe Kα line profiles commonly present in black hole binaries at high accretion rates. The narrow l…
White Dwarfs in the Era of the LSST and Its Synergies with Space-based Missions
McConnachie, Alan W.; Côté, Patrick; Fantin, Nicholas J.
With the imminent start of the Legacy Survey for Space and Time (LSST) at the Vera C. Rubin Observatory and several new space telescopes expected to begin operations later in this decade, both time-domain and wide-field astronomy are on the threshold of a new era. In this paper, we use a new multicomponent model for the distribution of white dwarf…
The power of coordinate transformations in dynamical interpretations of Galactic structure
Hogg, David W.; Kawata, Daisuke; Johnston, Kathryn V. +3 more
Gaia DR2 has provided an unprecedented wealth of information about the positions and motions of stars in our Galaxy and has highlighted the degree of disequilibria in the disc. As we collect data over a wider area of the disc, it becomes increasingly appealing to start analysing stellar actions and angles, which specifically label orbit space, ins…
Piercing through Highly Obscured and Compton-thick AGNs in the Chandra Deep Fields. II. Are Highly Obscured AGNs the Missing Link in the Merger-triggered AGN-Galaxy Coevolution Models?
Yang, Guang; Brandt, William N.; Comastri, Andrea +12 more
By using a large, highly obscured ( ${N}_{{\rm{H}}}\gt {10}^{23}\ {\mathrm{cm}}^{-2}$ ) active galactic nucleus (AGN) sample (294 sources at z ∼ 0-5) selected from detailed X-ray spectral analyses in the deepest Chandra surveys, we explore distributions of these X-ray sources in various optical/infrared/X-ray color-color diagrams and their host-ga…
Systematics and accuracy of VLBI astrometry: A comparison with Gaia Data Release 2
Liu, N.; Zhu, Z.; Liu, J. -C. +1 more
Context. The third generation of the ICRF - ICRF3 - was published in 2018. This new fundamental catalog provides radio source positions measured independently at three bands: S/X, K, and X/Ka, representing three independent radio celestial frames which altogether constitute a multi-frequency ICRF.
Aims: We aim to investigate the overall prope…
The M31/M33 tidal interaction: a hydrodynamic simulation of the extended gas distribution
Li, Di; Bland-Hawthorn, Joss; Tepper-García, Thor
We revisit the orbital history of the Triangulum galaxy (M33) around the Andromeda galaxy (M31) in view of the recent Gaia Data Release 2 proper motion measurements for both Local Group galaxies. Earlier studies consider highly idealized dynamical friction, but neglect the effects of dynamical mass loss. We show the latter process to be important …
Mid-infrared Studies of HD 113766 and HD 172555: Assessing Variability in the Terrestrial Zone of Young Exoplanetary Systems
Rieke, George H.; Gáspár, András; Meng, Huan Y. A. +4 more
We present multiepoch infrared photometry and spectroscopy obtained with warm Spitzer, Subaru, and the Stratospheric Observatory for Infrared Astronomy to assess variability for the young (∼20 Myr) and dusty debris systems around HD 172555 and HD 113766A. No variations (within 0.5%) were found for the former at either 3.6 or 4.5 µm, while si…
Simultaneous Observations of ELF/VLF Rising-Tone Quasiperiodic Waves and Energetic Electron Precipitations in the High-Latitude Upper Ionosphere
Lei, Jungang; Zhima, Zeren; Huang, Jianping +12 more
The quasiperiodic (QP) waves accompanied by simultaneous energetic electron precipitations in the high-latitude ionosphere were recorded by the sun-synchronous circular orbit China Seismo-Electromagnetic Satellite (CSES). The new features of QP waves observed by CSES are the well-pronounced rising-tone structures and very short repetition periods,…
Observations of Disintegrating Long-period Comet C/2019 Y4 (ATLAS): A Sibling of C/1844 Y1 (Great Comet)
Ye, Quan-Zhi; Hui, Man-To
We present a study of C/2019 Y4 (ATLAS) using Sloan gri observations from 2020 mid-January to early April. During this time span, the comet brightened with a growth in the effective cross-section of $\left(2.0\pm 0.1\right)\times {10}^{2}$ m2 s-1 from the beginning to ∼70 days preperihelion in late 2020 March, followed by a b…
Role of the impact parameter in exoplanet transmission spectroscopy
Strassmeier, K. G.; Mallonn, M.; von Essen, C. +3 more
Context. Transmission spectroscopy is a promising tool for the atmospheric characterization of transiting exoplanets. Because the planetary signal is faint, discrepancies have been reported regarding individual targets.
Aims: We investigate the dependence of the estimated transmission spectrum on deviations of the orbital parameters of the st…