Search Publications
Echelle Long-Slit Optical Spectroscopy of Evolved Stars
Sahai, R.; Sánchez Contreras, C.; Gil de Paz, A. +1 more
We present echelle long-slit optical spectra of a sample of objects evolving off the asymptotic giant branch (AGB), most of them in the preplanetary nebula (PPN) phase, obtained with the ESI and MIKE spectrographs at the 10 m Keck II and 6.5 m Magellan-I telescopes, respectively. The total wavelength range covered with ESI (MIKE) is ~3900-10900 Å …
Deep Chandra Monitoring Observations of NGC 3379: Catalog of Source Properties
Zezas, A.; Gallagher, J.; King, A. R. +11 more
We present the properties of the discrete X-ray sources detected in our monitoring program of the 'typical' elliptical galaxy, NGC 3379, observed with Chandra ACIS-S in five separate pointings, resulting in a co-added exposure of 324 ks. From this deep observation, 132 sources have been detected within the region overlapped by all observations, 98…
An X-Ray Survey of Wolf-Rayet Stars in the Magellanic Clouds. I. The Chandra ACIS Data Set
Guerrero, Martín A.; Chu, You-Hua
Wolf-Rayet (WR) stars are evolved massive stars with strong fast stellar winds. WR stars in our Galaxy have shown three possible sources of X-ray emission associated with their winds: shocks in the winds, colliding stellar winds, and wind-blown bubbles; however, quantitative analyses of observations are often hampered by uncertainties in distances…
Chandra ACIS Survey of M33 (ChASeM33): A First Look
Blair, William P.; Hughes, John P.; Sasaki, Manami +22 more
We present an overview of the Chandra ACIS Survey of M33 (ChASeM33): A Deep Survey of the Nearest Face-on Spiral Galaxy. The 1.4 Ms survey covers the galaxy out to R ≈ 18'(≈ 4 kpc) . These data provide the most intensive, high spatial resolution assessment of the X-ray source populations available for the confused inner regions of M33. Mosaic imag…
The Long-Term Variability of the X-Ray Sources in NGC 6946 and NGC 4485/4490
Kong, Albert K. H.; Homan, Jeroen; Fridriksson, Joel K. +2 more
We analyze data from five Chandra observations of the spiral galaxy NGC 6946 and from three Chandra observations of the irregular/spiral interacting galaxy pair NGC 4485/4490, with an emphasis on investigating the long-term variability exhibited by the source populations. We detect 90 point sources coincident with NGC 6946 down to luminosities of …
A New H I Survey of Active Galaxies
Ho, Luis C.; Greene, Jenny E.; Darling, Jeremy
We have conducted a new Arecibo survey for H I emission for 113 galaxies with broad-line (type 1) active galactic nuclei (AGNs) out to recession velocities as high as ~35,000 km s-1. The primary aim of the study is to obtain sensitive H I spectra for a well-defined, uniformly selected sample of active galaxies that have estimates of the…
The VLA Survey of the Chandra Deep Field-South. II. Identification and Host Galaxy Properties of Submillijansky Sources
Popesso, P.; Tozzi, P.; Silverman, J. +10 more
We present the optical and infrared identifications of the 266 radio sources detected at 20 cm with the Very Large Array in the Chandra Deep Field-South. Using deep i-band Advanced Camera for Surveys, R-band Wide Field Imager, K-band SOFI NTT, K-band ISAAC VLT and Spitzer imaging data, we are able to find reliable counterparts for 254 (~95%) VLA s…
A Catalog of Outer Ejecta Knots in the Cassiopeia A Supernova Remnant
Fesen, Robert A.; Hammell, Molly C.
Hubble Space Telescope images of the core-collapse supernova remnant Cassiopeia A are used to identify high-velocity knots of ejecta located outside the remnant's main emission shell of expanding debris. These ejecta fragments are found near or ahead of the remnant's forward shock front and mostly lie from 120'' to 300'' in r…
The ChaMP Extended Stellar Survey (ChESS): Photometric and Spectroscopic Properties of Serendipitously Detected Stellar X-Ray Sources
Silverman, J. D.; Covey, K. R.; Barkhouse, W. A. +9 more
We present 348 X-ray-emitting stars identified from correlating the Extended Chandra Multiwavelength Project (ChaMP), a wide-area serendipitous survey based on archival X-ray images, with the Sloan Digital Sky Survey (SDSS). We use morphological star/galaxy separation, matching to an SDSS quasar catalog, an optical color-magnitude cut, and X-ray d…
Adaptive Optics Rest-Frame V-Band Imaging of Lyman Break Galaxies at z~3: High Surface Density Disklike Galaxies?
Kobayashi, Naoto; Minowa, Yosuke; Ohta, Kouji +3 more
In order to reveal the rest-frame V-band morphology of galaxies at z ~ 3, we conducted AO-assisted K-band imaging observations of z ~ 3 LBGs whose absolute magnitudes range from MV* - 0.5 mag to MV* + 3.0 mag, with MV*, the characteristic absolute magnitude of z ~ 3 LBGs, of -24.0 mag. The AO observations resolve m…