Search Publications
A Magnified View of the Kinematics and Morphology of RCSGA 032727-132609: Zooming in on a Merger at z = 1.7
Rigby, Jane R.; Sharon, Keren; Gladders, Michael D. +1 more
We present a detailed analysis of multi-wavelength Hubble Space Telescope/Wide Field Camera 3 (WFC3) imaging and Keck/OSIRIS near-infrared adaptive optics-assisted integral field spectroscopy for a highly magnified lensed galaxy at z = 1.70. This young starburst is representative of ultraviolet-selected star-forming galaxies (SFGs) at z ~ 2 and co…
Interstellar and Ejecta Dust in the Cas A Supernova Remnant
Arendt, Richard G.; Hwang, Una; Rho, Jeonghee +2 more
Infrared continuum observations provide a means of investigating the physical composition of the dust in the ejecta and swept up medium of the Cas A supernova remnant (SNR). Using low-resolution Spitzer IRS spectra (5-35 µm), and broad-band Herschel PACS imaging (70, 100, and 160 µm), we identify characteristic dust spectra, associated…
A Molecular Line Scan in the Hubble Deep Field North
Daddi, E.; Maiolino, R.; Menten, K. M. +20 more
We present a molecular line scan in the Hubble Deep Field North (HDF-N) that covers the entire 3 mm window (79-115 GHz) using the IRAM Plateau de Bure Interferometer. Our CO redshift coverage spans z <~ 0.45, 1 <~ z <~ 1.9 and all z >~ 2. We reach a CO detection limit that is deep enough to detect essentially all z > 1 CO lines repo…
The Black Hole Mass of NGC 4151. II. Stellar Dynamical Measurement from Near-infrared Integral Field Spectroscopy
Peterson, Bradley M.; Pogge, Richard W.; Storchi-Bergmann, Thaisa +8 more
We present a revised measurement of the mass of the central black hole (M BH ) in the Seyfert 1 galaxy NGC 4151. The new stellar dynamical mass measurement is derived by applying an axisymmetric orbit-superposition code to near-infrared integral field data obtained using adaptive optics with the Gemini Near-infrared Integral Field Spect…
New Evidence for a Substellar Luminosity Problem: Dynamical Mass for the Brown Dwarf Binary Gl 417BC
Dupuy, Trent J.; Ireland, Michael J.; Liu, Michael C.
We present new evidence for a problem with cooling rates predicted by substellar evolutionary models that implies that model-derived masses in the literature for brown dwarfs and directly imaged planets may be too high. Based on our dynamical mass for Gl 417BC (L4.5+L6) and a gyrochronology system age from its young, solar-type host star, commonly…
Observational Characteristics of Coronal Mass Ejections without Low-coronal Signatures
Berghmans, D.; Seaton, D. B.; D'Huys, E. +1 more
Solar eruptions are usually associated with a variety of phenomena occurring in the low corona before, during, and after the onset of eruption. Though easily visible in coronagraph observations, so-called stealth coronal mass ejections (CMEs) do not obviously exhibit any of these low-coronal signatures. The presence or absence of distinct low-coro…
New Evidence for Efficient Collisionless Heating of Electrons at the Reverse Shock of a Young Supernova Remnant
Petre, Robert; Yamaguchi, Hiroya; Hughes, John P. +7 more
Although collisionless shocks are ubiquitous in astrophysics, certain key aspects of them are not well understood. In particular, the process known as collisionless electron heating, whereby electrons are rapidly energized at the shock front, is one of the main open issues in shock physics. Here, we present the first clear evidence for efficient c…
The Evolution of Galaxy Size and Morphology at z ~ 0.5-3.0 in the GOODS-N Region with Hubble Space Telescope/WFC3 Data
Kajisawa, Masaru; Morishita, Takahiro; Ichikawa, Takashi
We analyze the recently released Hubble Space Telescope/Wide Field Camera 3 IR images in the GOODS-N region to study the formation and evolution of quiescent galaxies (QGs). After examining the reliability of two-dimensional light profiles with artificial galaxies, we obtain the morphological parameters with Sérsic profile of 299 QGs and 1083 star…
WISE Y Dwarfs as Probes of the Brown Dwarf-Exoplanet Connection
Cushing, Michael C.; Kirkpatrick, J. Davy; Gelino, Christopher R. +5 more
We have determined astrometric positions for 15 WISE-discovered late-type brown dwarfs (six T8-9 and nine Y dwarfs) using the Keck-II telescope, the Spitzer Space Telescope, and the Hubble Space Telescope. Combining data from 8 to 20 epochs we derive parallactic and proper motions for these objects, which puts the majority within 15 pc. For ages g…
Winds of Low-metallicity OB-type Stars: HST-COS Spectroscopy in IC 1613
Garcia, Miriam; Herrero, Artemio; Najarro, Francisco +2 more
We present the first quantitative ultraviolet spectroscopic analysis of resolved OB stars in IC 1613. Because of its alleged very low metallicity (lsim1/10 Z ⊙, from H II regions), studies in this Local Group dwarf galaxy could become a significant step forward from the Small Magellanic Cloud (SMC) toward the extremely metal-poor massiv…