Search Publications
UV Excess Measures of Accretion onto Young Very Low Mass Stars and Brown Dwarfs
Herczeg, Gregory J.; Hillenbrand, Lynne A.
Low-resolution spectra from 3000 to 9000 Å of young low-mass stars and brown dwarfs were obtained with LRIS on Keck I. The excess UV and optical emission arising in the Balmer and Paschen continua yields mass accretion rates ranging from 2 × 10-12 to 10-8 M⊙ yr-1. These results are compared with HST STIS…
The Pulsating White Dwarf Stars
Fontaine, G.; Brassard, P.
We present a summary of what is currently known about the three distinct families of isolated pulsating white dwarfs. These are the GW Vir stars (He/C/O-atmosphere stars with Teff ≃ 120,000 K), the V777 Her stars (He-atmosphere, Teff ≃ 25,000 K), and the ZZ Ceti stars (H-atmosphere, Teff ≃ 12,000 K), all showing mu…
The Initial-Final Mass Relation: Direct Constraints at the Low-Mass End
Kelson, Daniel D.; Rich, R. Michael; Hansen, Brad M. S. +3 more
The initial-final mass relation represents a mapping between the mass of a white dwarf remnant and the mass that the hydrogen-burning main-sequence star that created it once had. The empirical relation thus far has been constrained using a sample of ~40 stars in young open clusters, ranging in initial mass from ~2.75 to 7 M⊙, and shows …
The unexpected origin of plasmaspheric hiss from discrete chorus emissions
Meredith, Nigel P.; Thorne, Richard M.; Bortnik, Jacob
Plasmaspheric hiss is a type of electromagnetic wave found ubiquitously in the dense plasma region that encircles the Earth, known as the plasmasphere. This important wave is known to remove the high-energy electrons that are trapped along the Earth's magnetic field lines, and therefore helps to reduce the radiation hazards to satellites and human…
The Structure of the Local Interstellar Medium. IV. Dynamics, Morphology, Physical Properties, and Implications of Cloud-Cloud Interactions
Redfield, Seth; Linsky, Jeffrey L.
We present an empirical dynamical model of the LISM based on 270 radial velocity measurements for 157 sight lines toward nearby stars. Physical parameter measurements (i.e., temperature, turbulent velocity, depletions) are available for 90 components, or one-third of the sample, enabling initial characterizations of the physical properties of LISM…
Reproducibility of Non-X-Ray Background for the X-Ray Imaging Spectrometer aboard Suzaku
Dotani, Tadayasu; Miller, Eric D.; Yamaguchi, Hiroya +9 more
One of the advantages of the X-ray Imaging Spectrometer (XIS) system aboard Suzaku is its low and stable non-X-ray background (NXB). In order to make the best use of this advantage, modeling the NXB spectra with high accuracy is important to subtract them from the spectra of on-source observations. We are constructing an NXB database by collecting…
FIREWORKS U38-to-24 µm Photometry of the GOODS Chandra Deep Field-South: Multiwavelength Catalog and Total Infrared Properties of Distant Ks-selected Galaxies
van Dokkum, Pieter G.; Franx, Marijn; Labbé, Ivo +4 more
We present a Ks-selected catalog, dubbed FIREWORKS, for the Chandra Deep Field-South (CDF-S) containing photometry in the U38, B435, B, V, V606, R, i775, I, z850, J, H, Ks, [3.6 µm], [4.5 µm], [5.8 µm], [8.0 µm], and MIPS [24 µm] bands. The i…
z ~ 7-10 Galaxies in the HUDF and GOODS Fields: UV Luminosity Functions
Franx, Marijn; Illingworth, Garth D.; Bouwens, Rychard J. +1 more
We use all available deep optical ACS and near-IR data over both the HUDF and the two GOODS fields to search for star-forming galaxies at zgtrsim 7 and constrain the UV LF within the first 700 Myr. Our data set includes ~23 arcmin2 of deep NICMOS J + H data and ~248 arcmin2 of ground-based (ISAAC+MOIRCS) data, coincident with…
Swift BAT Survey of AGNs
Gehrels, N.; Mushotzky, R. F.; Barthelmy, S. +5 more
We present the results of the analysis of the first 9 months of data of the Swift BAT survey of AGNs in the 14-195 keV band. Using archival X-ray data or follow-up Swift XRT observations, we have identified 129 (103 AGNs) of 130 objects detected at | b| > 15° and with significance >4.8 σ. One source remains unidentified. These same X-ray dat…
The Chandra Deep Field-South Survey: 2 Ms Source Catalogs
Smail, I.; Finoguenov, A.; Lehmer, B. D. +19 more
We present point-source catalogs for the ≈2 Ms exposure of the Chandra Deep Field-South (CDF-S); this is one of the two most sensitive X-ray surveys ever performed. The survey covers an area of ≈436 arcmin2 and reaches on-axis sensitivity limits of ≈1.9 × 10-17 and ≈1.3 × 10-16 ergs cm-2 s-1 f…