Search Publications
Resolving the Nuclear Radio Emission from M32 with the Very Large Array
Li, Zhiyuan; Yuan, Feng; Sjouwerman, Loránt O. +3 more
The Local Group dwarf elliptical galaxy M32 hosts one of the nearest and most under-luminous supermassive black holes (SMBHs) ever known, offering a rare opportunity to study the physics of accreting SMBHs at the most quiescent state. Recent Very Large Array (VLA) observations detected a radio source at the nucleus of M32, which was suggested to b…
HST/COS Observations of Quasar Outflows in the 500-1050 ŠRest Frame. VII. Distances and Energetics for 11 Outflows in Five Quasars
Xu, Xinfeng; Kriss, Gerard A.; Arav, Nahum +2 more
From Hubble Space Telescope/Cosmic Origins Spectrograph spectra of five quasars, 16 outflows are detected. For 11 outflows, we are able to constrain their distances to the central source (R) and their energetics. In instances of multiple electron number density determinations (used in the calculation of R) for the same outflow, the values are cons…
Exploiting morphological data from Pulsar Wind Nebulae via a spatiotemporal leptonic transport code
Venter, C.; Seyffert, A. S.; van Rensburg, C. +1 more
The next era of ground-based Cherenkov telescope development will see a great increase in both quantity and quality of γ-ray morphological data. This initiated the development of a spatiotemporal leptonic transport code to model pulsar wind nebulae. We present results from this code that predicts the evolution of the leptonic particle spectrum and…
Spatially Resolved Study of Recombining Plasma in W49B Using XMM-Newton
Auchettl, Katie; Holland-Ashford, Tyler; Lopez, Laura A.
W49B is the youngest supernova remnant (SNR) to date that exhibits recombining plasma. The two prevailing theories of this overionization are rapid cooling via adiabatic expansion or through thermal conduction with an adjacent cooler medium. To constrain the origin of the recombining plasma in W49B, we perform a spatially resolved spectroscopic st…
Resilient habitability of nearby exoplanet systems
Mustill, Alexander J.; Davies, Melvyn B.; Kokaia, Giorgi
We investigate the possibility of finding Earth-like planets in the habitable zone of 34 nearby FGK-dwarfs, each known to host one giant planet exterior to their habitable zone detected by RV. First we simulate the dynamics of the planetary systems in their present day configurations and determine the fraction of stable planetary orbits within the…
TESS photometry of extreme helium stars PV Tel and V821 Cen
Barentsen, Geert; Handler, Gerald; Jeffery, C. Simon
PV Tel variables are extreme helium (EHe) stars known to be intrinsic light and velocity variable on characteristic time-scales of 0.1-25 d. With two exceptions, they are best described as irregular. Light curves have invariably been obtained from single-site terrestrial observatories. We present Transiting Exoplanet Survey Satellite observations …
Search for He I airglow emission from the hot Jupiter τ Boo b
Zhang, Yapeng; Alonso-Floriano, F. J.; Snellen, I. A. G. +4 more
Context. It has been suggested that the helium absorption line at 10 830 Å that originates from the metastable triplet state 23S is an excellent probe for the extended atmospheres of hot Jupiters and their hydrodynamic escape processes. It has recently been detected in the transmission spectra of a handful of planets. The isotropic reem…
BepiColombo mission to Mercury: First year of flight
Montagnon, Elsa; Ferri, Paolo; Accomazzo, Andrea +1 more
Launched in October 2018, the ESA/JAXA BepiColombo mission is set to arrive at Mercury in late 2025. The modular S/C consists of two scientific Mercury orbiters and a cruise module with electric propulsion to support the 7-years cruise phase with planetary flybys at Earth (1x), Venus (2x) and Mercury (6x). Flight operations of the composite spacec…
Massive Stars in the SDSS-IV/APOGEE2 Survey. III. New OB Stars in the Direction of the Sagittarius Spiral Arm
Minniti, Dante; Roman-Lopes, Alexandre; Tapia, Mauricio +2 more
We have applied the semi-empirical spectral analysis, developed by the Sloan Digital Sky Survey (SDSS)-IV/Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE2) Massive Star Team, to a large sample of new O- and B-type stars identified along the Sagittarius spiral arm, in the direction of the southern star clusters NGC3603 and NGC3576.…
Mars's Red (575-625 nm) Seasonal Approximate Reflectivity Averaged Over Mars Years 24-28 From Mars Orbiter Camera
Robbins, Stuart J.
The Mars Global Surveyor spacecraft successfully orbited Mars for over nine Earth years, its instruments returning a plethora of data that still today form important, key data sets in Mars research. A relatively underutilized data set was returned from the Mars Orbiter Camera (MOC), specifically the wide-angle component (MOC-WA), despite returning…