Search Publications
The Absorption Signatures of Dwarf Galaxies: The z=1.04 Multicloud Weak Mg II Absorber toward PG 1634+706
Charlton, Jane C.; Churchill, Christopher W.; Zonak, Stephanie G. +1 more
We analyze high-resolution spectra of a multicloud weak [defined as Wr(MgII)<0.3 Å] absorbing system along the line of sight to PG 1634+706. This system gives rise to a partial Lyman limit break and absorption in Mg II, Si II, C II, Si III, Si IV, C IV, and O VI. The lower ionization transitions arise in two kinematic subsystems with…
Radiative Cooling and Heating and Thermal Conduction in M87
Molendi, Silvano; Ghizzardi, Simona; De Grandi, Sabrina +1 more
The crisis of the standard cooling flow model brought about by Chandra and XMM-Newton observations of galaxy clusters has led to the development of several models that explore different heating processes in order to assess whether they can quench the cooling flow. Among the most appealing mechanisms are thermal conduction and heating through buoya…
Hα-derived Star Formation Rates for the z = 0.84 Galaxy Cluster Cl J0023+0423B
Zaritsky, Dennis; Finn, Rose A.; McCarthy, Donald W., Jr.
We present Hα-derived star formation rates (SFRs) for the galaxy cluster Cl J0023+0423B at z=0.845. Our 3 σ flux limits correspond to an SFR of 0.24 h-2100 Msolar yr-1, and our minimum reliable Hα+[NII] equivalent width is greater than 10 Å, demonstrating that near-infrared narrowband imaging can sample …
Evolution in the Colors of Lyman Break Galaxies from z~4 to z~3
Papovich, Casey; Dickinson, Mark; Ferguson, Henry C. +11 more
The integrated colors of distant galaxies provide a means for interpreting the properties of their stellar content. Here we use rest-frame UV-to-optical colors to constrain the spectral energy distributions and stellar populations of color-selected, B-dropout galaxies at z~4 in the Great Observatories Origins Deep Survey (GOODS). We combine the Ad…
Far-Ultraviolet Spectroscopic Analyses of Four Central Stars of Planetary Nebulae
Bianchi, L.; Herald, J. E.
We analyze the far-UV/UV spectra of four central stars of planetary nebulae (CSPNs) with strong wind features-NGC 2371, A78, IC 4776, and NGC 1535-and derive their photospheric and wind parameters by modeling high-resolution FUSE (Far Ultraviolet Spectroscopic Explorer) data in the far-UV and HST (Hubble Space Telescope) STIS and IUE data in the U…
O VI, N V, and C IV in the Galactic Halo. II. Velocity-Resolved Observations with the Hubble Space Telescope and Far Ultraviolet Spectroscopic Explorer
Shull, J. Michael; Indebetouw, Rémy
We present a survey of N V and O VI (and, where available, C IV) in the Galactic halo, using data from the Far Ultraviolet Spectroscopic Explorer (FUSE) and the Hubble Space Telescope (HST) along 34 sight lines. These ions are usually produced in nonequilibrium processes such as shocks, evaporative interfaces, or rapidly cooling gas, and thus trac…
XMM-Newton Observations of A133: A Weak Shock Passing through the Cool Core
Sarazin, Craig L.; Reiprich, Thomas H.; Ehle, M. +5 more
We use XMM-Newton observations of the cluster of galaxies A133 to study the X-ray spectrum of the intracluster medium (ICM). We find a cold front to the southeast of the cluster core. From the pressure profile near the cold front, we derive an upper limit to the velocity of the core relative to the rest of the cluster of less than 230 km s-1<…
A Comparison of the Outer Atmosphere of the ``Flat Activity'' Star τ Ceti (G8 V) with the Sun (G2 V) and α Centauri A (G2 V)
Ayres, Thomas R.; Judge, Philip G.; Carlsson, Mats +1 more
Driven by the desire to understand the roles of acoustic and magnetic mechanisms in heating the outer atmospheres of Sun-like stars, we compare solar UV spectra with archival STIS spectra from the Hubble Space Telescope of α Cen A (G2 V) and new STIS spectra of the extremely inactive dwarf star τ Cet (G8 V, V=3.5). The activity of τ Cet shows occa…
Discovery of a Soft Spectral Component and Transient 22.7 Second Quasi-periodic Oscillations of SAX J2103.5+4545
Baykal, A.; İnam, S. Ç.; Swank, J. +1 more
XMM-Newton observed SAX J2103.5+4545 on 2003 January 6, while the Rossi X-Ray Timing Explorer (RXTE) was also monitoring the source. Using the RXTE Proportional Counter Array data set between 2002 December 3 and 2003 January 29, the spin period and average spin-up rate during the XMM-Newton observations were found to be 354.7940+/-0.0008 s and (7.…
Observations of Cold Dust in Nearby Elliptical Galaxies
Kuno, Nario; Haas, Martin; Sansom, Anne E. +2 more
Spectral energy distribution (SED) analyses that include new millimeter to far-infrared (FIR) observations obtained with continuum instruments on the Nobeyama and James Clerk Maxwell Telescopes and the Infrared Space Observatory are presented for seven nearby (<45 Mpc) FIR-bright elliptical galaxies. These are analyzed together with archival FI…