Search Publications
Infrared and X-Ray Evidence for Circumstellar Grain Destruction by the Blast Wave of Supernova 1987A
Polomski, Elisha F.; Gehrz, Robert D.; Woodward, Charles E. +10 more
Multiwavelength observations of supernova remnant 1987A show that its morphology and luminosity are rapidly changing at X-ray, optical, infrared (IR), and radio wavelengths as the blast wave from the explosion expands into the circumstellar equatorial ring, produced by mass loss from the progenitor star. The observed IR radiation arises from the i…
The Burst Spectra of EXO 0748-676 during a Long 2003 XMM-Newton Observation
Boirin, L.; Miller, J. M.; Lewin, W. H. G. +4 more
Gravitationally redshifted absorption lines from highly ionized iron have been previously identified in the burst spectra of the neutron star in EXO 0748-676. To repeat this detection we obtained a long, nearly 600 ks observation of the source with XMM-Newton in 2003. The spectral features seen in the burst spectra from the initial data are not re…
Spectral, Spatial, and Time Properties of the Hydrogen Nebula around Exoplanet HD 209458b
Ben-Jaffel, Lotfi
All far-ultraviolet (FUV) observations of HD 209458 tend to support a scenario in which the inflated hydrogen atmosphere of its planetary companion strongly absorbs the stellar Lyα flux during transit. However, it is not clear how the transit absorption depends on the selected wavelength range in the stellar line profile, nor how the atomic hydrog…
A STIS Survey for O VI Absorption Systems at 0.12 < z lesssim 0.5. I. The Statistical Properties of Ionized Gas
Chen, Hsiao-Wen; Thom, C.
We have conducted a systematic survey for intervening O VI absorbers in available echelle spectra of 16 QSOs at zQSO = 0.17-0.57. These spectra were obtained using HST STIS with the E140M grating. Our search uncovered a total of 27 foreground O VI absorbers with rest-frame absorption equivalent width Wr(1031) gtrsim 25 mÅ. Te…
Star Formation Rates in Lyman Break Galaxies: Radio Stacking of LBGs in the COSMOS Field and the Sub-µJy Radio Source Population
Smolčić, V.; Taniguchi, Y.; Yun, M. S. +10 more
We present an analysis of the radio properties of large samples of Lyman break galaxies (LBGs) at z ~ 3, 4, and 5 from the COSMOS field. The median stacking analysis yields a statistical detection of the z ~ 3 LBGs (U-band dropouts), with a 1.4 GHz flux density of 0.90 +/- 0.21 µJy. The stacked emission is unresolved, with a size <1, or a…
The Stellar Content of Galaxy Halos: A Comparison between ΛCDM Models and Observations of M31
Robertson, Brant E.; Tumlinson, Jason; Johnston, Kathryn V. +4 more
Recent observations have revealed that high surface brightness, metal-rich debris is present over large regions of the Andromeda (M31) stellar halo. We use a set of numerical models to determine whether extended metal-rich debris is expected to exist in galaxy halos formed in a hierarchical ΛCDM universe. We identify tidal debris in the simulation…
Tilt of Emerging Bipolar Magnetic Regions on the Sun
Kosovichev, A. G.; Stenflo, J. O.
Magnetic fields emerging from the Sun's interior carry information about the physical processes of magnetic field generation and transport in the convection zone. A statistical analysis of variations of the tilt angle of bipolar magnetic regions during the emergence, observed from SOHO MDI, shows that the systematic tilt with respect to the equato…
Supernova 1996cr: SN 1987A's Wild Cousin?
Bauer, F. E.; Brandt, W. N.; Dwarkadas, V. V. +4 more
We report on new VLT optical spectroscopic and multiwavelength archival observations of SN 1996cr, a previously identified ultraluminous X-ray source known as Circinus galaxy X-2. Our optical spectrum confirms SN 1996cr as a bona fide Type IIn supernova, while archival imaging from the Anglo-Australian Telescope archive isolates the explosion date…
The Complex Structure of the Cl 1604 Supercluster at z ~ 0.9
Kocevski, D.; Lemaux, B. C.; Lubin, L. M. +2 more
The Cl 1604 supercluster at z = 0.9 is one of a small handful of such structures discovered in the high-redshift universe and is the first target observed as part of the Observations of Redshift Evolution in Large Scale Environments (ORELSE) survey. To date, Cl 1604 is the largest structure mapped at z ~ 1, with the most constituent clusters and t…
X-Ray Properties of Protostars in the Orion Nebula
Robberto, M.; Grosso, N.; Micela, G. +8 more
The origin and evolution of the X-ray emission in very young stellar objects (YSOs) are not yet well understood because it is very hard to observe YSOs in the protostellar phase. Using COUP data, we study the X-ray properties of stars in the ONC in different evolutionary classes: luminosities, hydrogen column densities NH, effective pla…