Search Publications
Merging Galaxies in GOODS-S: First Extragalactic Results from Keck Laser Adaptive Optics
Koo, D. C.; Le Mignant, D.; Wright, S. A. +15 more
The Center for Adaptive Optics Treasury Survey aims to combine deep Hubble Space Telescope (HST) images in the optical with deep Keck adaptive optics (AO) data in the near-infrared (NIR) to study distant galaxies, active galactic nuclei, and supernovae. We recently achieved an important new milestone by securing the first Keck laser guide star AO …
Protostars, Dust Globules, and a Herbig-Haro Object in the LMC Superbubble N51D
Gruendl, R. A.; Smith, R. C.; Gordon, K. D. +9 more
Using Spitzer Space Telescope and Hubble Space Telescope observations of the superbubble N51D, we have identified three young stellar objects (YSOs) in dust globules and made the first detection of a Herbig-Haro object outside the Galaxy. The spectral energy distributions of these YSOs suggest young massive stars with disk, envelope, and outflow c…
XMM-Newton Observations of the M31 Northern Disk: Properties of Selected X-Ray Sources and Unresolved Emission
Mason, Keith; Trudolyubov, Sergey; Kotov, Oleg +2 more
We present the results of an XMM-Newton survey of the northern part of M31 disk. The X-ray properties of the 37 brightest sources are studied in detail. Combining the results of X-ray analysis with available data at other wavelengths, we were able to identify 19 out of 37 sources. Two sources in our sample were previously unknown: the hard X-ray s…
Probing Multiple Sight Lines through the SN 1006 Remnant by Ultraviolet Absorption Spectroscopy
Long, Knox S.; Fesen, Robert A.; Winkler, P. Frank +1 more
Absorption-line spectroscopy is an effective probe for cold ejecta within a supernova remnant (SNR), provided that suitable background UV sources can be identified. For the SN 1006 remnant we have identified four such sources, in addition to the much-studied Schweitzer-Middleditch (SM) star. We have used STIS on the Hubble Space Telescope to obtai…
The Nonhomologous Nature of Solar Diameter Variations
Basu, Sarbani; Sofia, Sabatino; Demarque, Pierre +2 more
We show in this Letter that the changes of the solar diameter in response to variations of large-scale magnetic fields and turbulence are not homologous. For the best current model, the variation at the photospheric level is over 1000 times larger than the variation at a depth of 5 Mm, which is about the level at which f-mode solar oscillations de…
Absolute Proper Motion of the Canis Major Dwarf Galaxy Candidate
Rix, Hans-Walter; Peñarrubia, Jorge; Girard, Terrence M. +4 more
We have measured the absolute proper motion of the candidate Canis Major dwarf galaxy (CMa), at (l,b)=(240°,-8°). Likely main-sequence stars in CMa have been selected from a region in the color-magnitude diagram that has very little contamination from known Milky Way components. We obtain µlcosb=-1.47+/-0.37 and µb
FUSE Measurements of Far-Ultraviolet Extinction. I. Galactic Sight Lines
Gordon, Karl D.; Sofia, Ulysses J.; Snow, Theodore P. +8 more
We present extinction curves that include data down to far-ultraviolet wavelengths (FUV; 1050-1200 Å) for nine Galactic sight lines. The FUV extinction was measured using data from the Far Ultraviolet Spectroscopic Explorer. The sight lines were chosen for their unusual extinction properties in the infrared through the ultraviolet; that they probe…
Metal Abundances in a Damped Lyα System along Two Lines of Sight at z = 0.93
Wisotzki, Lutz; Gregg, Michael D.; Lopez, Sebastian +3 more
We study metal abundances in the z=0.9313 damped Lyα system observed along the two lines of sight, A and B, toward the gravitationally lensed double QSO HE 0512-3329. Spatially resolved Space Telescope Imaging Spectrograph spectra constrain the neutral-gas column density to be N(HI)=1020.5 cm-2 in both A and B. UV-visual Eche…
The INTEGRAL/IBIS Source AX J1838.0-0655: A Soft X-Ray-to-TeV γ-Ray Broadband Emitter
Walter, R.; Bird, A. J.; Ubertini, P. +8 more
We report on INTEGRAL observations of AX J1838.0-0655, one of the unidentified objects listed in the first IBIS/ISGRI survey catalog and located in the Scutum arm region. This object, detected in the 20-300 keV band at a confidence level of 15.3 σ (9 × 10-11 ergs cm-2 s-1), is the likely counterpart of the still un…
The XMM-Newton Detection of Diffuse Inverse Compton X-Rays from Lobes of the FR II Radio Galaxy 3C 98
Isobe, N.; Makishima, K.; Tashiro, M. +1 more
The XMM-Newton observation of the nearby FR II radio galaxy 3C 98 is reported. In two exposures on the target, faint diffuse X-ray emission associated with the radio lobes was significantly detected together with a bright X-ray active nucleus, of which the 2-10 keV intrinsic luminosity is (4-8)×1042 ergs s-1. The EPIC spectra…