Search Publications
Determining the full magnetic field gradient from two spacecraft measurements under special constraints
Dunlop, M.; Rong, Z. J.; Shen, C.
In this exploration, it is revealed for the first time that the full magnetic field gradient and current density distribution can be derived from two spacecraft magnetic field measurements under the assumptions that the magnetic field is approximately stationary and force-free, conditions which are particularly relevant to low altitude regions of …
Near-infrared Survey of the GOODS-North Field: Search for Luminous Galaxy Candidates at z >~ 6.5
Ferguson, Henry C.; Hathi, Nimish P.; Mobasher, Bahram +2 more
We present near-infrared (NIR; J and K s) survey of the Great Observatories Origins Deep Survey-North (GOODS-N) field. The publicly available imaging data were obtained using the MOIRCS instrument on the 8.2 m Subaru and the WIRCam instrument on the 3.6 m Canada-France-Hawaii Telescope (CFHT). These observations fulfill a serious wavele…
Chandra and Hubble Space Telescope Observations of the Supersoft ULX in NGC 247: Candidate for Standard Disk Emission
Tao, Lian; Feng, Hua; Grisé, Fabien +2 more
We report on multiwavelength observations of the supersoft ultraluminous X-ray source (ULX) in NGC 247 made with the Chandra X-Ray Observatory and Hubble Space Telescope. We aligned the X-ray and optical images using three objects present on both and identified a unique, point-like optical counterpart to the ULX. The X-ray to optical spectrum is w…
Test of Shi et al. method to infer the magnetic reconnection geometry from spacecraft data: MHD simulation with guide field and antiparallel kinetic simulation
Hesse, M.; Birn, J.; Drake, J. F. +3 more
When analyzing data from an array of spacecraft (such as Cluster or MMS) crossing a site of magnetic reconnection, it is desirable to be able to accurately determine the orientation of the reconnection site. If the reconnection is quasi-two dimensional, there are three key directions, the direction of maximum inhomogeneity (the direction across th…
The Dwarf Starburst Host Galaxy of a Type Ia Supernova at z = 1.55 from CANDELS
Mobasher, Bahram; Riess, Adam G.; Hjorth, Jens +4 more
We present VLT/X-shooter observations of a high-redshift, Type Ia supernova (SN Ia) host galaxy, discovered with HST/WFC3 as part of the CANDELS Supernova project. The galaxy exhibits strong emission lines of Lyα, [O II], Hβ, [O III], and Hα at z = 1.54992+0.00008 -0.00004. From the emission-line fluxes and spectral energy di…
Planetary Nebulae Detected in the Spitzer Space Telescope GLIMPSE 3D Legacy Survey
Zhang, Yong; Kwok, Sun; Hsia, Chih-Hao
We used the data from the Spitzer Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) to investigate the mid-infrared (MIR) properties of planetary nebulae (PNs) and PN candidates. In previous studies of GLIMPSE I and II data, we have shown that these MIR data are very useful in distinguishing PNs from other emission-line objects. In the pre…
Latitudinal variation of upper tropospheric NH3 on Saturn derived from Cassini/CIRS far-infrared measurements
Fletcher, L. N.; Irwin, P. G. J.; Calcutt, S. B. +3 more
Ammonia (NH3) has been detected both on Saturn and Jupiter, and although its concentration and distribution has been well-studied on Jupiter, it has proven more difficult to do so on Saturn due to higher sensitivity requirements resulting from Saturn's lower atmospheric temperatures and the dominance of Saturn's phosphine which masks th…
Globular cluster systems in fossil groups: NGC 6482, NGC 1132, and ESO 306-017
Côté, P.; Blakeslee, J. P.; Jordán, A. +6 more
We study the globular cluster (GC) systems in three representative fossil group galaxies: the nearest (NGC 6482), the prototype (NGC 1132) and the most massive known to date (ESO 306-017). This is the first systematic study of GC systems in fossil groups. Using data obtained with the Hubble Space Telescope Advanced Camera for Surveys in the F475W …
Investigation of Quasi-periodic Solar Oscillations in Sunspots Based on SOHO/MDI Magnetograms
Riehokainen, A.; Kallunki, J.
In this work we study quasi-periodic solar oscillations in sunspots, based on the variation of the amplitude of the magnetic field strength and the variation of the sunspot area. We investigate long-period oscillations between three minutes and ten hours. The magnetic field synoptic maps were obtained from the SOHO/MDI. Wavelet (Morlet), global wa…
New Variable Jet Models for HH 34
Raga, A. C.; Noriega-Crespo, A.; Esquivel, A. +1 more
We consider newly derived proper motions of the HH 34 jet to reconstruct the evolution of this outflow. We first extrapolate ballistic trajectories for the knots (starting from their present-day positions and velocities) and find that at ~1000 yr in the future most of them will merge to form a larger-mass structure. This mass structure will be for…