Search Publications
Improving Galactic Center Astrometry by Reducing the Effects of Geometric Distortion
Ghez, A. M.; Anderson, J.; Lu, J. R. +4 more
We present significantly improved proper motion measurements of the Milky Way's central stellar cluster. These improvements are made possible by refining our astrometric reference frame with a new geometric optical distortion model for the W. M. Keck II 10 m telescope's adaptive optics camera (NIRC2) in its narrow field mode. For the first time, t…
Reversal of Fortune: Confirmation of an Increasing Star Formation-Density Relation in a Cluster at z = 1.62
Papovich, Casey; Finkelstein, Steven L.; Saintonge, Amélie +9 more
We measure the rest-frame colors (dust-corrected), infrared luminosities, star formation rates, and stellar masses of 92 galaxies in a Spitzer-selected cluster at z = 1.62. By fitting spectral energy distributions (SEDs) to 10-band photometry (0.4 µm<λobs < 8 µm) and measuring 24 µm fluxes for the 12 spectroscopi…
Dark Matter Contraction and the Stellar Content of Massive Early-type Galaxies: Disfavoring "Light" Initial Mass Functions
Treu, T.; Auger, M. W.; Gavazzi, R. +3 more
We use stellar dynamics, strong lensing, stellar population synthesis models, and weak lensing shear measurements to constrain the dark matter (DM) profile and stellar mass in a sample of 53 massive early-type galaxies. We explore three DM halo models (unperturbed Navarro, Frenk, and White (NFW) halos and the adiabatic contraction models of Blumen…
Hubble/COS Observations of the Lyα Forest Toward the BL Lac Object 1ES 1553+113
Shull, J. Michael; Danforth, Charles W.; Stocke, John T. +2 more
We present new moderate-resolution, far-ultraviolet spectra from the Hubble Space Telescope/Cosmic Origins Spectrograph (HST/COS) of the BL Lac object 1ES 1553+113 covering the wavelength range 1135 Å < λ < 1795 Å. The data show a smooth continuum with a wealth of narrow (b < 100 km s-1) absorption features arising in the inter…
On the Stellar Populations and Evolution of Star-forming Galaxies at 6.3 < z <= 8.6
Papovich, Casey; Finkelstein, Steven L.; Dickinson, Mark +4 more
Observations of very distant galaxies probe both the formation and evolution of galaxies, and also the nature of the sources responsible for reionizing the intergalactic medium (IGM). Here, we study the physical characteristics of galaxies at 6.3 < z <= 8.6, selected from deep near-infrared imaging with the Wide Field Camera 3 (WFC3) on boar…
An Atlas of z = 5.7 and z = 6.5 Lyα Emitters
Capak, P.; Barger, A. J.; Cowie, L. L. +3 more
We present an atlas of 88 z ~ 5.7 and 30 z ~ 6.5 Lyα emitters obtained from a wide-field narrowband survey. We combined deep narrowband imaging in 120 Å bandpass filters centered at 8150 Å and 9140 Å with deep BVRIz broadband imaging to select high-redshift galaxy candidates over an area of 4180 arcmin2. The goal was to obtain a uniform…
Color-Magnitude Relations of Active and Non-active Galaxies in the Chandra Deep Fields: High-redshift Constraints and Stellar-mass Selection Effects
Lehmer, B. D.; Alexander, D. M.; Silverman, J. D. +6 more
We extend color-magnitude relations for moderate-luminosity X-ray active galactic nucleus (AGN) hosts and non-AGN galaxies through the galaxy formation epoch (z ≈ 1-4) in the Chandra Deep Field-North and Chandra Deep Field-South (CDF-N and CDF-S, respectively; jointly CDFs) surveys. This study was enabled by the deepest available X-ray data from t…
Discovery of a Superluminal Fe K Echo at the Galactic Center: The Glorious Past of Sgr A* Preserved by Molecular Clouds
Ponti, G.; Terrier, R.; Goldwurm, A. +2 more
We present the result of a study of the X-ray emission from the galactic center (GC) molecular clouds (MCs) within 15 arcmin from Sgr A*. We use XMM-Newton data (about 1.2 Ms of observation time) spanning about eight years. The MC spectra show all the features characteristic of reflection: (1) intense Fe Kα, with equivalent width of about 0.7-1 ke…
Quiescent Prominence Dynamics Observed with the Hinode Solar Optical Telescope. I. Turbulent Upflow Plumes
Magara, Tetsuya; Shimizu, Toshifumi; Okamoto, Takenori J. +10 more
Hinode/Solar Optical Telescope (SOT) observations reveal two new dynamic modes in quiescent solar prominences: large-scale (20-50 Mm) "arches" or "bubbles" that "inflate" from below into prominences, and smaller-scale (2-6 Mm) dark turbulent upflows. These novel dynamics are related in that they are always dark in visible-light spectral bands, the…
Gas-phase Oxygen Gradients in Strongly Interacting Galaxies. I. Early-stage Interactions
Kewley, Lisa J.; Rupke, David S. N.; Chien, L. -H.
A consensus is emerging that interacting galaxies show depressed nuclear gas metallicities compared to isolated star-forming galaxies. Simulations suggest that this nuclear underabundance is caused by interaction-induced inflow of metal-poor gas and that this inflow concurrently flattens the radial metallicity gradients in strongly interacting gal…