Search Publications
The Wolf-Rayet + Black Hole Binary NGC 300 X-1: What is the Mass of the Black Hole?
Williams, Benjamin F.; Eracleous, Michael; Plucinsky, Paul P. +6 more
We present new X-ray and UV observations of the Wolf-Rayet + black hole (BH) binary system NGC 300 X-1 with the Chandra X-ray Observatory and the Hubble Space Telescope Cosmic Origins Spectrograph. When combined with archival X-ray observations, our X-ray and UV observations sample the entire binary orbit, providing clues to the system geometry an…
Interactions between large-scale radio structures and gas in a sample of optically selected type 2 quasars
Humphrey, A.; Storchi-Bergmann, T.; Bellocchi, E. +5 more
Context. The role of radio mode feedback in non radio-loud quasars needs to be explored in depth to determine its true importance. Its effects can be identified based on the evidence of interactions between the radio structures and the ambient ionised gas.
Aims: We investigate this interaction in a sample of 13 optically selected type 2 quasa…
Speckle Interferometry at SOAR in 2020
Henry, Todd J.; Tokovinin, Andrei; Mann, Andrew W. +3 more
The results of speckle interferometric observations at the 4.1 m Southern Astrophysical Research Telescope in 2020, as well as earlier unpublished data, are given, totaling 1735 measurements of 1288 resolved pairs and nonresolutions of 1177 targets. We resolved for the first time 59 new pairs or subsystems in known binaries, mostly among nearby dw…
Optical and Near-infrared Pulsation Properties of RR Lyrae and Population II Cepheid Variables in the Messier 15 Globular Cluster
Marconi, Marcella; Rejkuba, Marina; Yang, Soung-Chul +2 more
Messier 15 (NGC 7078) is an old and metal-poor post core-collapse globular cluster that hosts a rich population of variable stars. We report new optical (gi) and near-infrared (NIR, JKs) multi-epoch observations for 129 RR Lyrae, 4 Population II Cepheids (3 BL Herculis, 1 W Virginis), and 1 anomalous Cepheid variable candidate in M15 ob…
Solar wind current sheets and deHoffmann-Teller analysis. First results from Solar Orbiter's DC electric field measurements
André, N.; Fedorov, A.; Lavraud, B. +25 more
Context. Solar Orbiter was launched on 10 February 2020 with the purpose of investigating solar and heliospheric physics using a payload of instruments designed for both remote and in situ studies. Similar to the recently launched Parker Solar Probe, and unlike earlier missions, Solar Orbiter carries instruments designed to measure low-frequency D…
Could the Local Cavity be an Irregularly Shaped Strömgren Sphere?
Redfield, Seth; Linsky, Jeffrey L.
Extending for 50-200 pc in all directions from the Sun, the Local Cavity has been characterized as an old supernova bubble consisting of low-density million-degree plasma heated by supernova shocks. We summarize the arguments for and against this model and conclude that hydrogen in the Local Cavity is fully ionized, and the plasma near the Galacti…
SPT-CL J2032-5627: A new Southern double relic cluster observed with ASKAP
Pratt, G. W.; Bartalucci, I.; Johnston-Hollitt, M. +2 more
We present a radio and X-ray analysis of the galaxy cluster SPT-CL J2032-5627. Investigation of public data from the Australian Square Kilometre Array Pathfinder (ASKAP) at 943 MHz shows two previously undetected radio relics at either side of the cluster. For both relic sources, we utilise archival Australia Telescope Compact Array (ATCA) data at…
The ALMA Spectroscopic Survey in the HUDF: A Search for [C II] Emitters at 6 ≤ z ≤ 8
Carilli, Chris; Inami, Hanae; Stefanon, Mauro +18 more
The Atacama Large Millimeter/submillimeter Array (ALMA) Spectroscopic Survey in the Hubble Ultra Deep Field (ASPECS) Band 6 scan (212-272 GHz) covers potential [C II] emission in galaxies at 6 ≤ z ≤ 8 throughout a 2.9 arcmin2 area. By selecting on known Lyα emitters (LAEs) and photometric dropout galaxies in the field, we perform target…
Characterizing dynamical states of Galactic open clusters with Gaia DR2
Corradi, W. J. B.; Ferreira, F. A.; Maia, F. F. S. +2 more
In this work, we investigate the dynamical properties of 38 Galactic open clusters: 34 of them are located at low Galactic latitudes (|b| < 10°) and are projected against dense stellar fields; the other four comparison objects present clearer contrasts with the field population. We determine structural and time-related parameters that are assoc…
Gaia-based Isochronal, Kinematic, and Spatial Analysis of the ɛ Cha Association
Kastner, Joel H.; Dickson-Vandervelde, D. Annie; Wilson, Emily C.
The precise parallax, proper motion, and photometric measurements contained in Gaia Data Release 2 (DR2) offer the opportunity to reexamine the membership and ages of nearby young moving groups (NYMGs), i.e., loose groups of stars of age ≲100 Myr in the solar vicinity. Here, we analyze the available DR2 data for members and candidate members of th…