Search Publications
Missions
Journals
Publication Years
The Heliosphere and Local Interstellar Medium from Neutral Atom Observations at Energies Below 10 keV
Schwadron, Nathan A.; Izmodenov, Vladislav V.; Kucharek, Harald +8 more
As the heliosphere moves through the surrounding interstellar medium, a fraction of the interstellar neutral helium, hydrogen, and heavier species crossing the heliopause make it to the inner heliosphere as neutral atoms with energies ranging from few eV to several hundred eV. In addition, energetic neutral hydrogen atoms originating from solar wi…
Pulsating B stars in the Scorpius-Centaurus Association with TESS
Bedding, Timothy R.; White, Timothy R.; Saio, Hideyuki +1 more
We study 119 B stars located in the Scorpius-Centaurus Association using data from NASA's TESS Mission. We see pulsations in 81 stars (68 per cent) across the full range of effective temperatures. In particular, we confirm previous reports of low-frequency pulsations in stars whose temperatures fall between the instability strips of SPB stars (slo…
An extended stellar halo discovered in the Fornax dwarf spheroidal using Gaia EDR3
Hammer, François; Pawlowski, Marcel S.; Yang, Yanbin +1 more
We have studied the extent of the Red Giant Branch stellar population in the Fornax dwarf spheroidal galaxy using the spatially extended and homogeneous data set from Gaia EDR3. Our pre-selection of stars belonging to Fornax is based on their proper motions, parallaxes, and colour-magnitude diagram. The latter criteria provide a Fornax star sample…
Application of a Steady-state Accretion Disk Model to Spectrophotometry and High-resolution Spectra of Two Recent FU Ori Outbursts
Rodriguez, Antonio C.; Hillenbrand, Lynne A.
We apply a conventional accretion disk model to the FU Ori-type objects HBC 722 and Gaia 17bpi. Our base model is a steady-state, thin Keplerian disk featuring a modified Shakura-Sunyaev temperature profile, with each annulus radiating as an area-weighted spectrum given by a NextGen atmosphere at the appropriate temperature. We explore departures …
High-density disc reflection spectroscopy of low-mass active galactic nuclei
Fabian, A. C.; Pinto, C.; Gandhi, P. +13 more
The standard alpha-disc model predicts an anticorrelation between the density of the inner accretion disc and the black hole mass times square of the accretion rate, as seen in higher mass (MBH > 106 M⊙) active galactic nuclei (AGNs). In this work, we test the predictions of the alpha-disc model and study the pr…
The Fundamental Planes of black hole activity for radio-loud and radio-quiet quasars
Snios, Bradford; Siemiginowska, Aneta; Schwartz, Daniel A. +2 more
We examine the Fundamental Plane of black hole activity for correlations with redshift and radio loudness in both radio-loud and radio-quiet quasar populations. Sources are compiled from archival data of both radio-loud and radio-quiet quasars over redshifts 0.1 < z < 5.0 to produce a sample of 353 sources with known X-ray, radio, and black …
The Galactic Nova Rate: Estimates from the ASAS-SN and Gaia Surveys
Mukai, K.; Kochanek, C. S.; Hodgkin, S. T. +13 more
We present the first estimate of the Galactic nova rate based on optical transient surveys covering the entire sky. Using data from the All-Sky Automated Survey for Supernovae (ASAS-SN) and Gaia-the only two all-sky surveys to report classical nova candidates-we find 39 confirmed Galactic novae and 7 additional unconfirmed candidates discovered fr…
Interrogating Solar Flare Loop Models with IRIS Observations 1: Overview of the Models, and Mass flows
Kerr, Graham S.
Solar and stellar flares are transient yet dramatic events in the atmospheres of the Sun or stars, during which vast amounts of magnetic energy is liberated. This energy is subsequently transported through the solar atmosphere or into the heliosphere, and together with coronal mass ejections flares comprise a fundamental component of space weather…
The CARMENES search for exoplanets around M dwarfs. Two Saturn-mass planets orbiting active stars
Amado, P. J.; Caballero, J. A.; Pallé, E. +26 more
The CARMENES radial-velocity survey is currently searching for planets in a sample of 387 M dwarfs. Here we report on two Saturn-mass planets orbiting TYC 2187-512-1 (M* = 0.50 M⊙) and TZ Ari (M* = 0.15 M⊙), respectively. We obtained supplementary photometric time series, which we use along with spectros…
A Young, Low-density Stellar Stream in the Milky Way Disk: Theia 456
Kounkel, Marina; Covey, Kevin R.; Agüeros, Marcel A. +4 more
Our view of the variety of stellar structures pervading the local Milky Way has been transformed by the application of clustering algorithms to the Gaia catalog. In particular, several stellar streams have been recently discovered that are comprised of hundreds to thousands of stars and span several hundred parsecs. We analyze one such structure, …