An accurate determination of photospheric solar abundances requires detailed modeling of the solar granulation and accounting for departures from local...
A Reemerging Bright Soft X-Ray State of the Changing-look Active Galactic Nucleus 1ES 1927+654: A Multiwavelength View
1ES1927+654 is a nearby active galactic nucleus (AGN) that has shown an enigmatic outburst in optical/UV followed by X-rays, exhibiting strange variability...
We present comprehensive multiwavelength radio to X-ray observations of GRB 181201A spanning from ≈150 s to ≈163 days after the burst, comprising the first...
A Robust Age Indicator for Old Stellar Populations
We derive new spectral Hγ index definitions that are robust age indicators for old and relatively old stellar populations and therefore have great potential for...
A Robust Determination of the Size of Quasar Accretion Disks Using Gravitational Microlensing
Using microlensing measurements for a sample of 27 image pairs of 19 lensed quasars we determine a maximum likelihood estimate for the accretion disk size of an...
A Search for Faint Resolved Galaxies Beyond the Milky Way in DES Year 6: A New Faint, Diffuse Dwarf Satellite of NGC 55
We report results from a systematic wide-area search for faint dwarf galaxies at heliocentric distances from 0.3 to 2 Mpc using the full 6 yr of data from the...
A Search for Spectral Hysteresis and Energy-dependent Time Lags from X-Ray and TeV Gamma-Ray Observations of Mrk 421
Blazars are variable emitters across all wavelengths over a wide range of timescales, from months down to minutes. It is therefore essential to observe blazars...
A Search for Stellar Populations in High-Velocity Clouds
We report the results of a photometric search for giant stars associated with the cores of four high-velocity clouds (HVCs)-two of which are compact HVCs-using...
A Search for the Optical Counterpart to the Magnetar CXOU J010043.1-721134
After our tentative detection of an optical counterpart to CXOU J010043.1-721134 from archival Hubble Space Telescope (HST) imaging, we have followed up with...