Search Publications
A Newly Recognized Very Young Supernova Remnant in M83
Soria, Roberto; Blair, William P.; Whitmore, Bradley C. +7 more
As part of a spectroscopic survey of supernova remnant candidates in M83 using the Gemini-South telescope and Gemini Multi-Object Spectrograph, we have discovered one object whose spectrum shows very broad lines at Hα, [O I] λλ6300, 6363, and [O III] λλ4959, 5007, similar to those from other objects classified as "late time supernovae". Although s…
On the Possibility of Significant Electron Depletion due to Nanograin Charging in the Coma of Comet 67p/churyumov-gerasimenko near Perihelion
Wahlund, J. -E.; Vigren, E.; Galand, M. +2 more
We approach the complicated phenomena of gas-dust interactions in a cometary ionosphere, focusing in particular on the possibility of significant depletion in electron number density due to grain charging. Our one-dimensional ionospheric model, accounting for grain charging processes, is applied to the subsolar direction and the diamagnetic cavity…
Galaxy Formation at z > 3 Revealed by Narrowband-selected [O III] Emission Line Galaxies
Suzuki, Tomoko L.; Minowa, Yosuke; Koyama, Yusei +6 more
We present the physical properties of [O iii] emission line galaxies at z\gt 3 as the tracers of active galaxies at 1 Gyr before the peak epoch at z∼ 2. We have performed deep narrowband imaging surveys in the Subaru/XMM-Newton Deep Survey Field with the Multi-object InfraRed Camera and Spectrograph on the Subaru Telescope and have constructed coh…
Nanodust Detection between 1 and 5 AU Using Cassini Wave Measurements
Schippers, P.; André, N.; Kurth, W. S. +6 more
The solar system contains solids of all sizes, ranging from kilometer-sized bodies to nano-sized particles. Nanograins have been detected in situ in the Earth's atmosphere, near cometary and giant planet environments, and more recently in the solar wind at 1 AU. The latter nanograins are thought to be formed in the inner solar system dust cloud, m…
A Correlation between Lyα Spectral Line Profile and Rest-frame UV Morphology
Dickinson, Mark; Mobasher, Bahram; Hemmati, Shoubaneh +6 more
We explore the relationship between the spectral shape of the Lyα emission and the UV morphology of the host galaxy using a sample of 304 Lyα-emitting BVi-dropouts at 3 < z < 7 in the Great Observatories Origins Deep Survey and Cosmic Evolution Survey fields. Using our extensive reservoir of high-quality Keck DEIMOS spectra combined with Hub…
Evidence of the Dynamics of Relativistic Jet Launching in Quasars
Punsly, Brian
Hubble Space Telescope (HST) spectra of the EUV, the optically thick emission from the innermost accretion flow onto the central supermassive black hole, indicate that radio loud quasars (RLQs) tend to be EUV weak compared to the radio-quiet quasars; yet the remainder of the optically thick thermal continuum is indistinguishable. The deficit of EU…
A Direct Measurement of the Forward Shock Speed in Supernova Remnant 0509-67.5: Constraints on the Age, Ambient Density, Shock Compression Factor, and Electron-ion Temperature Equilibration
Hughes, John P.; Hovey, Luke; Eriksen, Kristoffer
Two Hubble Space Telescope narrow-band Hα images separated in time by 1.03 years are used for a proper motion measurement of the forward shock of the LMC supernova remnant 0509-67.5, the only spectroscopically confirmed LMC remnant of Ia origin. We measure a global shock speed of 6500 ± 200 km s-1 and constrain the pre-shock neutral hyd…
The Accreting Black Hole Swift J1753.5-0127 from Radio to Hard X-Ray
Done, Chris; Kaaret, Philip; Gandhi, Poshak +19 more
We report on multiwavelength measurements of the accreting black hole Swift J1753.5-0127 in the hard state at low luminosity (L ∼ 2.7 × 1036 erg s-1 assuming a distance of d = 3 kpc) in 2014 April. The radio emission is optically thick synchrotron, presumably from a compact jet. We take advantage of the low extinction (E(B-V)…
Investigation of the Progenitors of the Type Ia Supernovae Associated with the LMC Supernova Remnants 0505-67.9 and 0509-68.7
Schaefer, Bradley E.; Pagnotta, Ashley
Although Type Ia supernovae have been heavily scrutinized due to their use in making cosmological distance estimates, we are still unable to definitively identify the progenitors for the entire population. While answers have been presented for certain specific systems, a complete solution remains elusive. We present observations of two supernova r…
X-Ray Fading and Expansion in the “Miniature Supernova Remnant” of GK Persei
Yamaguchi, H.; Uchiyama, Y.; Drake, J. J. +3 more
We report on a second epoch of Chandra X-ray imaging spectroscopy of the spatially resolved old nova remnant GK Persei. An ACIS-S3 observation of 97.4 ks was conducted in 2013 November after a lapse of 13.8 yr from the last visit in 2000. The X-ray emitting nebula appeared more faint and patchy compared with the first epoch. The flux decline was p…