Search Publications
Strengthening the Case for Asteroidal Accretion: Evidence for Subtle and Diverse Disks at White Dwarfs
Zuckerman, B.; Jura, M.; Farihi, J. +1 more
Spitzer Space Telescope IRAC 3-8 µm and AKARI IRC 2-4 µm photometry are reported for 10 white dwarfs with photospheric heavy elements; nine relatively cool stars with photospheric calcium and one hotter star with a peculiar high carbon abundance. A substantial infrared excess is detected at HE 2221-1630, while modest excess emissions a…
On the Existence of Energetic Atoms in the Upper Atmosphere of Exoplanet HD209458b
Ben-Jaffel, Lotfi; Sona Hosseini, S.
Stellar irradiation and particle forcing strongly affect the immediate environment of extrasolar giant planets orbiting near their parent stars. However, it is not clear how the energy is deposited over the planetary atmosphere, nor how the momentum and energy spaces of the different species that populate the system are modified. Here, we use far-…
Confirmation of the Compactness of a z = 1.91 Quiescent Galaxy with Hubble Space Telescope's Wide Field Camera 3
van Dokkum, Pieter G.; Franx, Marijn; Illingworth, Garth D. +6 more
We present very deep Wide Field Camera 3 (WFC3) photometry of a massive, compact galaxy located in the Hubble Ultra Deep Field. This quiescent galaxy has a spectroscopic redshift z = 1.91 and has been identified as an extremely compact galaxy by Daddi et al. We use new H F160W imaging data obtained with Hubble Space Telescope/WFC3 to me…
Probing the Terminator Region Atmosphere of the Hot-Jupiter XO-1b with Transmission Spectroscopy
Tinetti, G.; Burke, C.; Griffith, C. A. +5 more
We report here the first infrared spectrum of the hot-Jupiter XO-1b. The observations were obtained with the NICMOS instrument on board the Hubble Space Telescope during a primary eclipse of the XO-1 system. Near photon-noise-limited spectroscopy between 1.2 and 1.8 µm allows us to determine the main composition of this hot-Jupiter's planeta…
Low-Redshift Lyα Selected Galaxies from GALEX Spectroscopy: A Comparison with Both UV-Continuum Selected Galaxies and High-Redshift Lyα Emitters
Cowie, Lennox L.; Barger, Amy J.; Hu, Esther M.
We construct a sample of low-redshift Lyα emission-line selected sources from Galaxy Evolution Explorer (GALEX) grism spectroscopy of nine deep fields to study the role of Lyα emission in galaxy populations with cosmic time. Our final sample consists of 119 (141) sources selected in the redshift interval z = 0.195-0.44 (z = 0.65-1.25) from the FUV…
Multiple Stellar Populations in the Galactic Globular Cluster NGC 6752
Anderson, J.; Milone, A. P.; Marino, A. F. +6 more
We have carried out high-precision photometry on a large number of archival Hubble Space Telescope images of the Galactic globular cluster NGC 6752, to search for signs of multiple stellar populations. We find a broadened main sequence (MS) and demonstrate that this broadening cannot be attributed either to binaries or to photometric errors. There…
The Absolute Magnitudes of Type Ia Supernovae in the Ultraviolet
Filippenko, Alexei V.; Foley, Ryan J.; Kirshner, Robert P. +19 more
We examine the absolute magnitudes and light-curve shapes of 14 nearby (redshift z = 0.004-0.027) Type Ia supernovae (SNe Ia) observed in the ultraviolet (UV) with the Swift Ultraviolet/Optical Telescope. Colors and absolute magnitudes are calculated using both a standard Milky Way extinction law and one for the Large Magellanic Cloud that has bee…
LoCuSS: Calibrating Mass-observable Scaling Relations for Cluster Cosmology with Subaru Weak-lensing Observations
Zhang, Y. -Y.; Finoguenov, A.; Smith, G. P. +4 more
We present a joint weak-lensing/X-ray study of galaxy cluster mass-observable scaling relations motivated by the critical importance of accurate calibration of mass proxies for future X-ray missions, including eROSITA. We use a sample of 12 clusters at z ~= 0.2 that we have observed with Subaru and XMM-Newton to construct relationships between the…
HST/COS Observations of the Quasar HE 2347-4342: Probing the Epoch of He II Patchy Reionization at Redshifts z = 2.4-2.9
Shull, J. Michael; Danforth, Charles W.; France, Kevin +2 more
We report ultraviolet spectra of the high-redshift (z em ≈ 2.9) quasar, HE 2347 - 4342, taken by the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope. Spectra in the G130M (medium resolution, 1135-1440 Å) and G140L (low resolution, 1030-2000 Å) gratings exhibit patchy Gunn-Peterson absorption in the 303.78 Å Lyα line of H…
Interplanetary Shocks Lacking Type II Radio Bursts
Kaiser, M. L.; Howard, R. A.; Gopalswamy, N. +5 more
We report on the radio-emission characteristics of 222 interplanetary (IP) shocks detected by spacecraft at Sun-Earth L1 during solar cycle 23 (1996 to 2006, inclusive). A surprisingly large fraction of the IP shocks (~34%) was radio quiet (RQ; i.e., the shocks lacked type II radio bursts). We examined the properties of coronal mass ejections (CME…