Search Publications
The Luminosity Function of Lyα Emitters at Redshift z = 7.7
Finkelstein, Steven L.; Dickinson, Mark; Tilvi, Vithal +8 more
Lyα emission lines should be attenuated in a neutral intergalactic medium. Therefore, the visibility of Lyα emitters at high redshifts can serve as a valuable probe of reionization at about the 50% level. We present an imaging search for z = 7.7 Lyα emitting galaxies using an ultra-narrowband filter (filter width = 9 Å) on the NEWFIRM imager at th…
Estimating Luminosity Function Constraints from High-Redshift Galaxy Surveys
Robertson, Brant E.
The installation of the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) will revolutionize the study of high-redshift galaxy populations. Initial observations of the HST Ultra Deep Field (UDF) have yielded multiple z >~ 7 dropout candidates. Supplemented by the GOODS Early Release Science (ERS) and further UDF pointings, these da…
The Last Eight-Billion Years of Intergalactic C IV Evolution
Prochaska, J. Xavier; Chen, Hsiao-Wen; Thom, Christopher +1 more
We surveyed the Hubble Space Telescope UV spectra of 49 low-redshift quasars for z < 1 C IV candidates, relying solely on the characteristic wavelength separation of the doublet. After consideration of the defining traits of C IV doublets (e.g., consistent line profiles, other associated transitions, etc.), we defined a sample of 38 definite (g…
Observations of Anisotropic Scaling of Solar Wind Turbulence
Wu, D. J.; Luo, Q. Y.
Using high-speed solar wind data recorded by the Ulysses spacecraft, we investigate and estimate the anisotropic inertial range scaling of the interplanetary magnetic field. We apply the method of the magnetic structure function (MSF), Sn (τ) = lang|b(t + τ) - b(t)| n rang vprop τζ(n), to analyze the scaling of sol…
Evidence for Granulation in Early A-Type Stars
Kallinger, Thomas; Matthews, Jaymie M.
Stars with spectral types earlier than about F0 on (or close) to the main sequence have long been believed to lack observable surface convection, although evolutionary models of A-type stars do predict very thin surface convective zones. We present evidence for granulation in two δ Scuti stars of spectral type A2: HD 174936 and HD 50844. Recent an…
On the Morphology of the Electron-Positron Annihilation Emission as Seen by Spi/integral
Bouchet, L.; Jourdain, E.; Roques, J. P.
The 511 keV positron annihilation emission remains a mysterious component of the high energy emission of our Galaxy. Its study was one of the key scientific objectives of the SPI spectrometer on board the International Gamma-Ray Astrophysics Laboratory satellite. In fact, a lot of observing time has been dedicated to the Galactic disk with a parti…
Free Magnetic Energy and Flare Productivity of Active Regions
Xu, Yan; Jing, Ju; Wang, Haimin +4 more
In this study, the photospheric vector magnetograms, obtained with the Spectro-Polarimeter of the Solar Optical Telescope on board Hinode, are used as the boundary conditions to extrapolate the three-dimensional nonlinear force-free (NLFF) coronal magnetic fields. The observed non-force-free photospheric magnetic fields are preprocessed toward the…
The Nova Shell and Evolution of the Recurrent Nova T Pyxidis
Schaefer, Bradley E.; Shara, Michael M.; Pagnotta, Ashley
T Pyxidis (T Pyx) is the prototypical recurrent nova (RN), with five eruptions from 1890 to 1967 and a mysterious nova shell. We report new observations of the nova shell with the Hubble Space Telescope (HST) in the year 2007, which provides a long time baseline to compare with HST images from 1994 and 1995. We find that the knots in the nova shel…
A Multi-wavelength View of the Star Formation Activity at z ~ 3
Daddi, E.; Elbaz, D.; Dickinson, M. +5 more
We present a multi-wavelength, UV-to-radio analysis for a sample of massive (M * ~ 1010 M sun) IRAC- and MIPS 24 µm detected Lyman break galaxies (LBGs) with spectroscopic redshifts z ~ 3 in the GOODS-North field. For LBGs without individual 24 µm detections, we employ stacking techniques at 24 µm…
Well-sampled Far-infrared Spectral Energy Distributions of z ~ 2 Galaxies: Evidence for Scaled up Cool Galaxies
Franx, Marijn; Muzzin, Adam; Labbé, Ivo +4 more
We present an analysis of the far-infrared (FIR) spectral energy distributions (SEDs) of two massive K-selected galaxies at z= 2.122 and z= 2.024 detected at 24 µm, 70 µm, 160 µm by Spitzer, 250 µm, 350 µm, 500 µm by BLAST, and 870 µm by APEX. The large wavelength range of these observations and the availa…