Search Publications
Compton-thick AGNs in the NuSTAR Era. III. A Systematic Study of the Torus Covering Factor
Cusumano, G.; Vignali, C.; Comastri, A. +9 more
We present the analysis of a sample of 35 candidate Compton-thick active galactic nuclei (AGNs) selected in the nearby universe (average redshift < z> ∼ 0.03) with the Swift-BAT 100-month survey. All sources have available NuSTAR data, thus allowing us to constrain with unprecedented quality important spectral parameters such as the obscurin…
Combined Effects of Rotation and Age Spreads on Extended Main-Sequence Turn Offs
Dolphin, Andrew E.; Williams, Benjamin F.; Johnson, L. Clifton +10 more
The extended main-sequence turn offs (eMSTOs) of several young to intermediate age clusters are examined in the Magellanic Clouds and the Milky Way. We explore the effects of extended star formation (eSF) and a range of stellar rotation rates on the behavior of the color-magnitude diagram, paying particular attention to the MSTO. We create synthet…
The Carnegie-Chicago Hubble Program. VII. The Distance to M101 via the Optical Tip of the Red Giant Branch Method
Madore, Barry F.; Freedman, Wendy L.; Beaton, Rachael L. +9 more
The Carnegie-Chicago Hubble Program (CCHP) is building a direct path to the Hubble constant (H 0) using Population II stars as the calibrator of the Type Ia supernova (SN Ia)-based distance scale. This path to calibrate the SNe Ia is independent of the systematics in the traditional Cepheid-based technique. In this paper, we present the…
Hi-C 2.1 Observations of Jetlet-like Events at Edges of Solar Magnetic Network Lanes
Tiwari, Sanjiv K.; Winebarger, Amy R.; Warren, Harry P. +15 more
We present high-resolution, high-cadence observations of six, fine-scale, on-disk jet-like events observed by the High-resolution Coronal Imager 2.1 (Hi-C 2.1) during its sounding-rocket flight. We combine the Hi-C 2.1 images with images from the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) and the Interface Region Imaging S…
The MASSIVE Survey. XII. Connecting Stellar Populations of Early-type Galaxies to Kinematics and Environment
Ma, Chung-Pei; Greene, Jenny E.; Blakeslee, John P. +6 more
We measure the stellar populations as a function of the radius for 90 early-type galaxies (ETGs) in the MASSIVE survey, a volume-limited integral-field spectroscopic (IFS) galaxy survey targeting all northern-sky ETGs with an absolute K-band magnitude of M K < -25.3 mag or a stellar mass of {M}* ≳ 4× {10}11 {M…
An Exo-Kuiper Belt with an Extended Halo around HD 191089 in Scattered Light
Debes, John H.; Schneider, Glenn; Duchêne, Gaspard +70 more
We have obtained Hubble Space Telescope STIS and NICMOS and Gemini/GPI scattered-light images of the HD 191089 debris disk. We identify two spatial components: a ring resembling the Kuiper Belt in radial extent (FWHM ∼ 25 au, centered at ∼46 au) and a halo extending to ∼640 au. We find that the halo is significantly bluer than the ring, consistent…
PDS 70: A Transition Disk Sculpted by a Single Planet
van der Marel, Nienke; Muley, Dhruv; Fung, Jeffrey
The wide, deep cavities of transition disks are often believed to have been hollowed out by nascent planetary systems. PDS 70, a ∼5 Myr old transition disk system in which a multi-Jupiter-mass planet candidate at 22 au coexists with a ∼30 au gas and ∼60 au dust-continuum gap, provides a valuable case study for this hypothesis. Using the PEnGUIn hy…
Dynamical Histories of the Crater II and Hercules Dwarf Galaxies
Simon, Joshua D.; Fu, Sal Wanying; Alarcón Jara, Alex G.
We investigate the possibility that the dwarf galaxies Crater II and Hercules have previously been tidally stripped by the Milky Way. We present Magellan/IMACS spectra of candidate member stars in both objects. We identify 37 members of Crater II, 25 of which have velocity measurements in the literature, and we classify three stars within that sub…
Extended Main-sequence Turnoffs in the Double Cluster h and χ Persei: The Complex Role of Stellar Rotation
Milone, Antonino P.; Cordoni, Giacomo; Deng, Licai +4 more
Using Gaia Data Release 2 photometry, we report the detection of extended main-sequence turnoff (eMSTO) regions in the color-magnitude diagrams (CMDs) of the ∼14 Myr old double clusters h and χ Persei (NGC 869 and NGC 884). We find that stars with masses below ∼1.3 M ⊙ in both h and χ Persei populate narrow main sequences (MSs), while m…
The Resolved Distributions of Dust Mass and Temperature in Local Group Galaxies
Sandstrom, Karin M.; Leroy, Adam K.; Chiang, I-Da +2 more
We utilize archival far-infrared maps from the Herschel Space Observatory in four Local Group galaxies (Small and Large Magellanic Clouds (SMC and LMC), M31, and M33). We model their spectral energy distribution from 100 to 500 µm using a single-temperature modified blackbody emission with a fixed emissivity index of β = 1.8. From the best-f…