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…
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…
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…
A Wide Planetary-mass Companion to a Young Low-mass Brown Dwarf in Ophiuchus
Albert, Loïc; Liu, Michael C.; Zhang, Zhoujian +6 more
We present the discovery of a planetary-mass companion to CFHTWIR-Oph 98, a low-mass brown dwarf member of the young Ophiuchus star-forming region, with a wide 200 au separation (1"46). The companion was identified using Hubble Space Telescope images, and confirmed to share common proper motion with the primary using archival and new ground-based …
Multiwavelength Absolute Magnitudes and Colors of Red Clump Stars in the Gaia Era
Bilir, Selçuk; Plevne, Olcay; Seabroke, George M. +1 more
This study presents the multiwavelength investigation of the absolute magnitudes and colors of the red clump (RC) stars selected from APOGEE and GALAH DR2 combined catalog which is complemented with Gaia DR2 astrometric data and multiwavelength photometric data of GALEX GR6/7, SDSS DR7, Gaia DR2, 2MASS, and WISE sky surveys. The analyses are cente…
Kinematics of the Magellanic Stream and Implications for Its Ionization
Richter, Philipp; Bland-Hawthorn, Joss; Fox, Andrew J. +3 more
The Magellanic Stream and the Leading Arm form a massive, filamentary system of gas clouds surrounding the Large and Small Magellanic Clouds. Here we present a new component-level analysis of their ultraviolet (UV) kinematic properties using a sample of 31 sightlines through the Magellanic System observed with the Hubble Space Telescope/Cosmic Ori…
An Accreting, Anomalously Low-mass Black Hole at the Center of Low-mass Galaxy IC 750
Gelfand, Joseph D.; Chen, Yan-Ping; Greenhill, Lincoln J. +5 more
We present a multiwavelength study of the active galactic nucleus in the nearby (D = 14.1 Mpc) low-mass galaxy IC 750, which has circumnuclear 22 GHz water maser emission. The masers trace a nearly edge-on, warped disk ∼0.2 pc in diameter, coincident with the compact nuclear X-ray source that lies at the base of the ∼kiloparsec-scale extended X-ra…
X-Ray Spectroscopy in the Microcalorimeter Era. II. A New Diagnostic on Column Density from the Case A to B Transition in H- and He-like Iron
Ferland, G. J.; Su, Y.; Chakraborty, P. +2 more
The Soft X-ray Spectrometer on board Hitomi, with the unprecedented resolving power of R ∼ 1250, allowed the detection of members of the Fe XXV Kα complex emission spectra from the center of the Perseus Cluster. In this paper, we introduce a novel method of measuring the column density using the optically thin (Case A) to optically thick (Case B) …
Constraining the Mass of the Emerging Galaxy Cluster SpARCS1049+56 at z = 1.71 with Infrared Weak Lensing
Muzzin, Adam; Perlmutter, Saul; Wilson, Gillian +4 more
In the hierarchical structure formation model of the universe, galaxy clusters are assembled through a series of mergers. Accordingly, it is expected that galaxy clusters in the early universe are actively forming and dynamically young. Located at a high redshift of z = 1.71, SpARCS1049+56 offers a unique look into the galaxy cluster formation pro…