Search Publications
A parsec-scale radio jet launched by the central intermediate-mass black hole in the dwarf galaxy SDSS J090613.77+561015.2
Paragi, Zsolt; Frey, Sándor; Yang, Jun +4 more
The population of intermediate-mass black holes (IMBHs) in nearby dwarf galaxies plays an important 'ground truth' role in exploring black hole formation and growth in the early Universe. In the dwarf elliptical galaxy SDSS J090613.77+561015.2 (z = 0.0465), an accreting IMBH has been revealed by optical and X-ray observations. Aiming to search for…
A Massive Molecular Torus inside a Gas-poor Circumnuclear Disk in the Radio Galaxy NGC 1052 Discovered with ALMA
Kohno, Kotaro; Terashima, Yuichi; Nakai, Naomasa +7 more
We report ALMA observations of NGC 1052 to search for mass accretion in a gas-poor active galactic nucleus. We detected CO emission representing a rotating ring-like circumnuclear disk (CND) seen edge-on with a gas mass of 5.3 × 105 M⊙. The CND has smaller gas mass than that in typical Seyfert galaxies with circumnuclear star…
Power spectra of solar brightness variations at various inclinations
Solanki, S. K.; Shapiro, A. I.; Tagirov, R. V. +4 more
Context. Magnetic features on the surfaces of cool stars lead to variations in their brightness. Such variations on the surface of the Sun have been studied extensively. Recent planet-hunting space telescopes have made it possible to measure brightness variations in hundred thousands of other stars. The new data may undermine the validity of setti…
Seasonal changes in the middle atmosphere of Titan from Cassini/CIRS observations: Temperature and trace species abundance profiles from 2004 to 2017
Bézard, Bruno; Vinatier, Sandrine; Jennings, Donald E. +6 more
The Cassini/Composite InfraRed Spectrometer (CIRS) instrument has been observing the middle atmosphere of Titan over almost half a Saturnian year. We used the CIRS dataset processed through the up-to-date calibration pipeline to characterize seasonal changes of temperature and abundance profiles in the middle atmosphere of Titan, from mid-northern…
Discovery of a soft X-ray lag in the ultraluminous X-ray source NGC 1313 X-1
Fabian, A. C.; Pinto, C.; Bachetti, M. +14 more
Ultraluminous X-ray sources (ULXs) provide a unique opportunity to probe the geometry and energetics of super-Eddington accretion. The radiative processes involved in super-Eddington accretion are not well understood, and so studying correlated variability between different energy bands can provide insights into the causal connection between diffe…
Cosmological insights into the assembly of the radial and compact stellar halo of the Milky Way
Hernquist, Lars; Helmi, Amina; Sales, Laura V. +1 more
Recent studies using Gaia DR2 have identified a massive merger in the early history of the Milky Way (MW) whose debris is dominated by radial and counterrotating orbits. This event, dubbed the Gaia-Enceladus/Gaia-Sausage (GE/GS), is also hypothesized to have built the majority of the inner stellar halo. We use the cosmological hydrodynamic simulat…
TOI-1728b: The Habitable-zone Planet Finder Confirms a Warm Super-Neptune Orbiting an M-dwarf Host
Cochran, William D.; Endl, Michael; Mahadevan, Suvrath +23 more
We confirm the planetary nature of TOI-1728b using a combination of ground-based photometry, near-infrared Doppler velocimetry and spectroscopy with the Habitable-zone Planet Finder. TOI-1728 is an old, inactive M0 star with Teff = ${3980}_{-32}^{+31}$ K, which hosts a transiting super-Neptune at an orbital period of ∼3.49 days. Joint f…
Local RR Lyrae stars: native and alien
Chen, X.; Zinn, R.; Layden, A. C. +1 more
Measurements of [Fe/H] and radial velocity are presented for 89 RR Lyrae (RRL) candidates within 6 kpc of the Sun. After the removal of two suspected non-RRLs, these stars were added to an existing data base, which yielded 464 RRLs with [Fe/H] on a homogeneous scale. Using data from the Gaia satellite (Data Release 2), we calculated the positions …
Mono-enriched stars and Galactic chemical evolution. Possible biases in observations and theory
Strassmeier, K. G.; Ilyin, I.; Hansen, C. J. +9 more
A long sought after goal using chemical abundance patterns derived from metal-poor stars is to understand the chemical evolution of the Galaxy and to pin down the nature of the first stars (Pop III). Metal-poor, old, unevolved stars are excellent tracers as they preserve the abundance pattern of the gas from which they were born, and hence they ar…
HD 62542: Probing the Bare, Dense Core of a Translucent Interstellar Cloud
York, Donald G.; Welty, Daniel E.; Snow, Theodore P. +1 more
We discuss the interstellar absorption from many atomic and molecular species seen in high-resolution Hubble Space Telescope/STIS UV and high signal-to-noise ratio optical spectra of the moderately reddened B3-5 V star HD 62542. This remarkable sight line exhibits both very steep far-UV extinction and a high fraction of hydrogen in molecular form,…