Search Publications
Non-local Thermal Equilibrium Model Atmospheres for the Hottest White Dwarfs: Spectral Analysis of the Compact Component in Nova V4743 Sgr
Nelson, T.; Rauch, T.; Werner, K. +4 more
Half a year after its outburst in 2002 September, nova V4743 Sgr evolved into the brightest supersoft X-ray source in the sky with a flux maximum around 30 Å. We calculated grids of synthetic energy distributions based on non-local thermal equilibrium model atmospheres for the analysis of the hottest white dwarfs (WDs) and present the result of fi…
Broad H I Absorbers as Metallicity-independent Tracers of the Warm-Hot Intergalactic Medium
Shull, J. Michael; Danforth, Charles W.; Stocke, John T.
Thermally broadened Lyα absorbers (BLAs) offer an alternative method to highly ionized metal lines for tracing the warm-hot intergalactic medium (WHIM) at T>105 K. However, observing BLAs requires data of high quality and accurate continuum definition to detect the low-contrast features, and a good knowledge of the velocity structure…
On the Progenitor and Early Evolution of the Type II Supernova 2009kr
Sollerman, J.; Gal-Yam, A.; Smartt, S. J. +15 more
We identify a source coincident with SN 2009kr in Hubble Space Telescope pre-explosion images. The object appears to be a single point source with an intrinsic color V - I = 1.1 ± 0.25 and MV = -7.6 ± 0.6. If this is a single star, it would be a yellow supergiant of log L/L sun ~ 5.1 and a mass of 15+5 -4
Total Molecular Gas Masses of z ~ 3 Lyman- break Galaxies: CO(J = 1 → 0) Emission in MS 1512-cB58 and the Cosmic Eye
Walter, Fabian; Momjian, Emmanuel; Carilli, Christopher L. +1 more
We report the detection of CO(J = 1 → 0) emission toward the lensed L sstarf UV Lyman-break galaxies (LBGs) MS 1512-cB58 (z = 2.73) and the Cosmic Eye (z = 3.07), using the Expanded Very Large Array. The strength of the CO line emission reveals molecular gas reservoirs with masses of (4.6 ± 1.1) × 108 (µ…
Optical IFU Observations of the Brightest Cluster Galaxy NGC 4696: The Case for a Minor Merger and Shock-excited Filaments
Dopita, M. A.; Farage, C. L.; McGregor, P. J. +1 more
We present deep optical integral-field spectroscopic observations of the nearby (z ~ 0.01) brightest cluster galaxy NGC 4696 in the core of the Centaurus Cluster, made with the Wide Field Spectrograph on the Australian National University 2.3 m telescope at Siding Spring Observatory. We investigate the morphology, kinematics, and excitation of the…
The Origin of [O II] in Post-starburst and Red-sequence Galaxies in High-redshift Clusters
Kocevski, D.; Lemaux, B. C.; Lubin, L. M. +3 more
We present the first results from a near-IR spectroscopic campaign of the Cl1604 supercluster at z ~ 0.9 and the cluster RX J1821.6+6827 at z ~ 0.82 to investigate the nature of [O II] λ3727 emission in cluster galaxies at high redshift. Of the 401 members in Cl1604 and RX J1821+6827 confirmed using the Keck II/DEIMOS spectrograph, 131 galaxies ha…
An Assessment of the Energy Budgets of Low-Ionization Nuclear Emission Regions
Eracleous, Michael; Flohic, Hélène M. L. G.; Hwang, Jason A.
Using the spectral energy distributions (SEDs) of the weak active galactic nuclei (AGNs) in 35 low-ionization nuclear emission regions (LINERs) presented in a companion paper, we assess whether photoionization by the weak AGN can power the emission-line luminosities measured through the large (few-arcsecond) apertures used in ground-based spectros…
Which Galaxies Host Bars and Disks? A Study of the Coma Cluster
Aguerri, J. A. L.; Sánchez-Janssen, R.; Méndez-Abreu, J.
We present a study of the bar fraction in the Coma Cluster galaxies based on a sample of ~190 galaxies selected from the Sloan Digital Sky Survey Data Release 6 and observed with the Hubble Space Telescope (HST) Advanced Camera for Survey (ACS). The unprecedented resolution of the HST-ACS images allows us to explore the presence of bars, detected …
COBE and the Galactic Interstellar Medium: Geometry of the Spiral Arms from FIR Cooling Lines
Wolfire, Mark; Hollenbach, David; Steiman-Cameron, Thomas Y.
We present a new model for the spiral structure of the Milky Way based upon the essentially all-sky intensity maps of the [C II] 158 µm and [N II] 205 µm lines of the interstellar medium (ISM) obtained by the FIRAS instrument of the Cosmic Background Explorer (COBE), with ancillary data from the Balloon-borne Infrared Carbon Explorer, …
Supernova Remnants and the Interstellar Medium of M83: Imaging and Photometry with the Wide Field Camera 3 on the Hubble Space Telescope
Mutchler, Max; Windhorst, Rogier; Blair, William P. +23 more
We present Wide Field Camera 3 images taken with the Hubble Space Telescope within a single field in the southern grand design star-forming galaxy M83. Based on their size, morphology, and photometry in continuum-subtracted Hα, [S II], Hβ, [O III], and [O II] filters, we have identified 60 supernova remnant (SNR) candidates, as well as a handful o…