Search Publications
A Gaia-based Catalog of Candidate Stripped Nuclei and Luminous Globular Clusters in the Halo of Centaurus A
Caldwell, Nelson; Strader, Jay; Seth, Anil C. +4 more
Tidally stripped galaxy nuclei and luminous globular clusters (GCs) are important tracers of the halos and assembly histories of nearby galaxies, but are difficult to reliably identify with typical ground-based imaging data. In this paper we present a new method to find these massive star clusters using Gaia DR2, focusing on the massive elliptical…
Super Star Clusters in the Central Starburst of NGC 4945
Meier, David S.; Ott, Jürgen; Bolatto, Alberto D. +12 more
The nearby (3.8 Mpc) galaxy NGC 4945 hosts a nuclear starburst and Seyfert type 2 active galactic nucleus (AGN). We use the Atacama Large Millimeter/submillimeter Array (ALMA) to image the 93 GHz (3.2 mm) free-free continuum and hydrogen recombination line emission (H40α and H42α) at 2.2 pc (0"12) resolution. Our observations reveal 27 bright, com…
A Catalog of AGN Host Galaxies Observed with HST/ACS: Correlations between Star Formation and AGN Activity
Griffith, Roger L.; Stern, Daniel; Stemo, Aaron +3 more
We present the Advanced Camera for Surveys Active Galactic Nuclei (ACS-AGN) Catalog, a catalog of 2585 active galactic nucleus (AGN) host galaxies that are at redshifts 0.2 < z < 2.5 and that were imaged with the Hubble Space Telescope’s Advanced Camera for Surveys (ACS). Using the ACS General Catalog (ACS-GC) as our initial sample, we selec…
GJ 1252 b: A 1.2 R⊕ Planet Transiting an M3 Dwarf at 20.4 pc
Vanderburg, Andrew; Hellier, Coel; Latham, David W. +35 more
We report the discovery of GJ 1252 b, a planet with a radius of 1.193 ± 0.074 ${R}_{\oplus }$ and an orbital period of 0.52 days around an M3-type star (0.381 ± 0.019 ${M}_{\odot }$ , 0.391 ± 0.020 ${R}_{\odot }$ ) located 20.385 ± 0.019 pc away. We use Transiting Exoplanet Survey Satellite (TESS) data, ground-based photometry and spectroscopy, Ga…
Search for Continuous Gravitational Waves from the Central Compact Objects in Supernova Remnants Cassiopeia A, Vela Jr., and G347.3-0.5
Gotthelf, E. V.; Allen, B.; Dergachev, V. +6 more
We perform a sub-threshold follow-up search for continuous nearly monochromatic gravitational waves from the central compact objects associated with the supernova remnants (SNRs) Vela Jr., Cassiopeia A, and SNR G347.3-0.5. Across the three targets, we investigate the most promising ≈10,000 combinations of gravitational-wave frequency and frequency…
A Diffuse Metal-poor Component of the Sagittarius Stream Revealed by the H3 Survey
Conroy, Charlie; Ting, Yuan-Sen; Cargile, Phillip A. +6 more
The tidal disruption of the Sagittarius dwarf galaxy has generated a spectacular stream of stars wrapping around the entire Galaxy. We use data from Gaia and the H3 Stellar Spectroscopic Survey to identify $823$ high-quality Sagittarius members based on their angular momenta. The H3 Survey is largely unbiased in metallicity, and so our sample of S…
The Semiforbidden C III] λ1909 Emission in the Rest-ultraviolet Spectra of Green Pea Galaxies
Ferguson, Henry C.; Ravindranath, Swara; Jaskot, Anne +2 more
We used the Space Telescope Imaging Spectrograph on the Hubble Space Telescope (HST) to observe the semiforbidden C III] λλ1907, 1909 doublet emission in green pea galaxies at 0.13 ≤ z ≤ 0.3. We detect C III] emission in 7/10 galaxies with C III] equivalent widths (EWs) that range from 2 to 10 Å, confirming that C III] emission is almost ubiquitou…
Evidence for a Highly Opaque Large-scale Galaxy Void at the End of Reionization
Ouchi, Masami; Shibuya, Takatoshi; Kashino, Daichi +2 more
We present evidence that a region of high effective Lyα optical depth at z ∼ 5.7 is associated with an underdense region at the tail end of cosmic reionization. We carried out a survey of Lyman-break Galaxies (LBGs) using Subaru Hyper Suprime-Cam in the field of the z = 5.98 quasar J0148+0600, whose spectrum presents an unusually long (∼160 cMpc) …
Five New Post-main-sequence Debris Disks with Gaseous Emission
Hermes, J. J.; Clemens, J. C.; Lai, Samuel +13 more
Observations of debris disks, the products of the collisional evolution of rocky planetesimals, can be used to trace planetary activity across a wide range of stellar types. The most common end points of stellar evolution are no exception, as debris disks have been observed around several dozen white dwarf stars. But instead of planetary formation…
The Relative Emission from Chromospheres and Coronae: Dependence on Spectral Type and Age
Brown, Alexander; Wheatley, Peter J.; France, Kevin +12 more
Extreme-ultraviolet and X-ray emission from stellar coronae drives mass loss from exoplanet atmospheres, and ultraviolet emission from stellar chromospheres drives photochemistry in exoplanet atmospheres. Comparisons of the spectral energy distributions of host stars are, therefore, essential for understanding the evolution and habitability of exo…