Search Publications
A KS and IRAC Selection of High-redshift Extremely Red Objects
Wang, Wei-Hao; Cowie, Lennox L.; Barger, Amy J.
In order to find the most extreme dust-hidden high-redshift galaxies, we select 196 extremely red objects in the KS and Infrared Array Camera (IRAC) bands (KIEROs, [Ks - 4.5 µm]AB > 1.6) in the 0.06 deg2 Great Observatories Origins Deep Surveys-North (GOODS-N) region. This selection avoids the B…
Spectroscopic Observations of Fe XVIII in Solar Active Regions
Teriaca, Luca; Warren, Harry P.; Curdt, Werner
The large uncertainties associated with measuring the amount of high temperature emission in solar active regions (ARs) represents a significant impediment to making progress on the coronal heating problem. Most current observations at temperatures of 3 MK and above are taken with broadband soft X-ray instruments. Such measurements have proven dif…
The 21 cm "Outer Arm" and the Outer-galaxy High-velocity Clouds: Connected by Kinematics, Metallicity, and Distance
Tripp, Todd M.; Song, Limin
Using high-resolution ultraviolet spectra obtained with the Hubble Space Telescope Space Telescope Imaging Spectrograph and the Far Ultraviolet Spectroscopic Explorer, we study the metallicity, kinematics, and distance of the gaseous "outer arm" (OA) and the high-velocity clouds (HVCs) in the outer Galaxy. We detect the OA in a variety of absorpti…
Temperature and Extreme-ultraviolet Intensity in a Coronal Prominence Cavity and Streamer
Landi, E.; Gibson, S. E.; Kucera, T. A. +2 more
We analyze the temperature and EUV line emission of a coronal cavity and surrounding streamer in terms of a morphological forward model. We use a series of iron line ratios observed with the Hinode Extreme-ultraviolet Imaging Spectrograph (EIS) on 2007 August 9 to constrain temperature as a function of altitude in a morphological forward model of …
HST and Optical Data Reveal White Dwarf Cooling, Spin, and Periodicities in GW Librae 3-4 Years after Outburst
Hermes, J. J.; Winget, D. E.; Szkody, Paula +9 more
Since the large amplitude 2007 outburst which heated its accreting, pulsating white dwarf, the dwarf nova system GW Librae has been cooling to its quiescent temperature. Our Hubble Space Telescope ultraviolet spectra combined with ground-based optical coverage during the third and fourth year after outburst show that the fluxes and temperatures ar…
First Three-dimensional Reconstructions of Coronal Loops with the STEREO A+B Spacecraft. IV. Magnetic Modeling with Twisted Force-free Fields
DeRosa, Marc L.; Nitta, Nariaki V.; Aschwanden, Markus J. +3 more
The three-dimensional coordinates of stereoscopically triangulated loops provide strong constraints for magnetic field models of active regions in the solar corona. Here, we use STEREO/A and B data from some 500 stereoscopically triangulated loops observed in four active regions (2007 April 30, May 9, May 19, and December 11), together with SOHO/M…
Probing Dynamical Processes in the Planet-forming Region with Dust Mineralogy
Manoj, P.; Watson, D. M.; Sargent, B. +6 more
We present Herschel Space Observatory PACS spectra of GQ Lup, a protoplanetary disk in the Lupus star-forming region. Through spectral energy distribution fitting from 0.3 µm to 1.3 mm, we construct a self-consistent model of this system's temperature and density structures, finding that although it is 3 Myr old, its dust has not settled to …
The Dynamics and Heating of Active Region Loops
Doschek, G. A.
I examine the dynamics of active regions using spectra obtained by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. I show the relationship between non-thermal velocities, Doppler outflows and downflows, intensities, and electron density for two representative active regions out of a group of 18 active regions examined.…
The Hubble Space Telescope Cluster Supernova Survey. VI. The Volumetric Type Ia Supernova Rate
Gladders, M. D.; Panagia, N.; Huang, X. +41 more
We present a measurement of the volumetric Type Ia supernova (SN Ia) rate out to z ~= 1.6 from the Hubble Space Telescope Cluster Supernova Survey. In observations spanning 189 orbits with the Advanced Camera for Surveys we discovered 29 SNe, of which approximately 20 are SNe Ia. Twelve of these SNe Ia are located in the foregrounds and background…
On the Force-free Nature of Photospheric Sunspot Magnetic Fields as Observed from Hinode (SOT/SP)
Tiwari, Sanjiv Kumar
A magnetic field is force-free if there is no interaction between it and the plasma in the surrounding atmosphere, i.e., electric currents are aligned with the magnetic field, giving rise to zero Lorentz force. The computation of various magnetic parameters, such as magnetic energy (using the virial theorem), gradient of twist of sunspot magnetic …