Search Publications
Gemini Imaging of the Host Galaxies of Changing-look Quasars
Anderson, Scott F.; Eracleous, Michael; Haggard, Daryl +4 more
Changing-look (CL) quasars are a newly discovered class of luminous active galactic nuclei that undergo rapid (≲10 yr) transitions between Type 1 and Type 1.9/2, with an associated change in their continuum emission. We characterize the host galaxies of four faded CL quasars using broadband optical imaging. We use gri images obtained with the Gemi…
Nonequilibrium Ionization Effects on Solar EUV and X-Ray Imaging Observations
Moon, Yong-Jae; Reeves, Katharine K.; Raymond, John C. +3 more
During transient events such as major solar eruptions, the plasma can be far from the equilibrium ionization state because of rapid heating or cooling. Nonequilibrium ionization (NEI) is important in rapidly evolving systems where the thermodynamical timescale is shorter than the ionization or recombination timescales. We investigate the effects o…
Luminosity Ratio between [O IV] 25.89 µm Line and Nuclear Continuum 12 µm as a Diagnostic for “Buried” AGNs
Imanishi, Masatoshi; Tanimoto, Atsushi; Ueda, Yoshihiro +3 more
We propose new diagnostics that utilize the [O IV] 25.89 µm and nuclear (subarcsecond scale) 12 µm luminosity ratios for identifying whether an active galactic nucleus (AGN) is deeply “buried” in their surrounding materials. Utilizing a sample of 16 absorbed AGNs at redshifts lower than 0.03 in the Swift/BAT catalog observed with Suzak…
HST F160W Imaging of Very Massive Galaxies at 1.5 < z < 3.0: Diversity of Structures and the Effect of Close Pairs on Number Density Estimates
Franx, Marijn; Muzzin, Adam; Labbé, Ivo +10 more
We present a targeted follow-up Hubble Space Telescope WFC3 F160W imaging study of very massive galaxies ({log}({M}star}/{M}⊙ )> 11.25) selected from a combination of ground-based near-infrared galaxy surveys (UltraVISTA, NEWFIRM Medium Band Survey-II , UKIRT Infrared Deep Sky Survey (UKIDSS) Ultra-Deep Survey (UDS) at 1.5…
A Submillimeter Perspective on the GOODS Fields (SUPER GOODS). IV. The Submillimeter Properties of X-Ray Sources in the CDF-S
Bauer, F. E.; Barger, A. J.; Cowie, L. L. +1 more
The Chandra Deep Field (CDF)-S is the deepest X-ray image available and will remain so for the near future. We provide a spectroscopic (64.5%; 64% with spectral classifications) and photometric redshift catalog for the full 7 Ms sample, but much of our analysis focuses on the central (off-axis angles <5.‧7) region, which contains a large, faint…
Forbush Decreases and <2 Day GCR Flux Non-recurrent Variations Studied with LISA Pathfinder
Mendes, L.; Russano, G.; Lloro, I. +82 more
Non-recurrent short-term variations of the galactic cosmic-ray (GCR) flux above 70 MeV n-1 were observed between 2016 February 18 and 2017 July 3 on board the European Space Agency LISA Pathfinder (LPF) mission orbiting around the Lagrange point L1 at 1.5 × 106 km from Earth. The energy dependence of three Forbush decreases i…
On the Origin of the Scatter in the Red Sequence: An Analysis of Four CLASH Clusters
Donahue, Megan; Kelson, Daniel D.; Moustakas, John +1 more
In clusters of galaxies, the red sequence is believed to be a consequence of a correlation between stellar mass and chemical abundances, with more massive galaxies being more metal-rich and, as a consequence, redder. However, there is a color scatter around the red sequence that holds even with precision photometry, implying that the galaxy popula…
Galaxies of the z ∼ 2 Universe. I. Grism-selected Rest-frame Optical Emission-line Galaxies
Yang, Guang; Schneider, Donald P.; Gronwall, Caryl +6 more
Euclid, the Wide Field Infrared Survey Telescope, and the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) will make emission-line selected galaxies the largest observed constituent in the z > 1 universe. However, we only have a limited understanding of the physical properties of galaxies selected via their Lyα or rest-frame optical emiss…
Angular Sizes, Radii, and Effective Temperatures of B-type Stars from Optical Interferometry with the CHARA Array
Gies, Douglas R.; Schaefer, Gail H.; Huber, Daniel +2 more
We present interferometric observations of 25 spectral type-B stars that were made with the Precision Astronomical Visible Observations and the CLassic Interferometry with Multiple Baselines beam combiners at the Center for High Angular Resolution Astronomy Array (CHARA). The observations provide the angular sizes of these stars with an average er…
Line Profiles of the Calcium I Resonance Line in Cool Metal-polluted White Dwarfs
Dufour, P.; Allard, N. F.; Blouin, S. +2 more
Metal-polluted white dwarfs (DZ stars) are characterized by a helium-rich atmosphere contaminated by heavy elements traces originating from accreted rocky planetesimals. As a detailed spectroscopic analysis of those objects can reveal the composition of the accreted debris, there is a great interest in developing accurate DZ atmosphere models. How…