Search Publications
Abundances in the H I Envelope of the Extremely Low Metallicity Blue Compact Dwarf Galaxy SBS 0335-052 from Far Ultraviolet Spectroscopic Explorer Observations
Thuan, Trinh X.; Izotov, Yuri I.; Lecavelier des Etangs, Alain
We present Far Ultraviolet Spectroscopic Explorer spectroscopy of SBS 0335-052, the second most metal-deficient blue compact dwarf (BCD) galaxy known [log(O/H)=-4.70]. In addition to the H I Lyman series, we detect C II, N I, N II, O I, Si II, Ar I, and Fe II absorption lines, mainly arising from the extended H I envelope in which SBS 0335-052 is …
Localized fast flow disturbance observed in the plasma sheet and in the ionosphere
Balogh, A.; Lester, M.; André, M. +8 more
An isolated plasma sheet flow burst took place at 22:02 UT, 1 September 2002, when the Cluster footpoint was located within the area covered by the Magnetometers-Ionospheric Radars-All-sky Cameras Large Experiment (MIRACLE). The event was associated with a clear but weak ionospheric disturbance and took place during a steady southward IMF interval…
Oxygen Ions Observed Near Saturn's A Ring
Luhmann, J. G.; Ip, W. -H.; Mueller-Wodarg, I. +8 more
Ions were detected in the vicinity of Saturn's A ring by the Ion and Neutral Mass Spectrometer (INMS) instrument onboard the Cassini Orbiter during the spacecraft's passage over the rings. The INMS saw signatures of molecular and atomic oxygen ions and of protons, thus demonstrating the existence of an ionosphere associated with the A ring. A like…
New Silhouette Disks with Reflection Nebulae and Outflows in the Orion Nebula and M43
Smith, Nathan; Bally, John; Walawender, Josh +1 more
We report the detection of several new circumstellar disks seen in silhouette against background nebular light in the outskirts of the Orion Nebula and the neighboring H II region M43. These were detected as part of our Hα survey of Orion with the Advanced Camera for Surveys on board the Hubble Space Telescope. Several of the disks show bipolar re…
Stellar populations and Lyα emission in two lensed z>~ 6 galaxies
Schaerer, Daniel; Pelló, Roser
We present an analysis of two strongly lensed galaxies at z= 6.56 and z~ 7 for which multi-band photometric and spectroscopic observations are available. For one source, the data include recent Hubble Space Telescope (HST) and Spitzer observations. Using a spectral energy distribution (SED) fitting technique considering a number of parameters (var…
Spectra of High-Redshift Type Ia Supernovae and a Comparison with Their Low-Redshift Counterparts
Wang, L.; Lidman, C.; Nugent, P. E. +33 more
We present spectra for 14 high-redshift (0.17<z<0.83) supernovae, which were discovered by the Supernova Cosmology Project as part of a campaign to measure cosmological parameters. The spectra are used to determine the redshift and classify the supernova type, essential information if the supernovae are to be used for cosmological studies. R…
Molecular Hydrogen
Maiolino, Roberto; Habart, Emilie; Walmsley, Malcolm +5 more
Observations of H2 line emission in galactic and extragalactic environments obtained with the Infrared Space Observatory (ISO) are reviewed. The diagnostic capability of H2 observations is illustrated. We discuss what one has learned about such diverse astrophysical sources as photon-dominated regions, shocks, young stellar o…
Discovery of Extremely Embedded X-Ray Sources in the R Coronae Australis Star-forming Core
Hamaguchi, Kenji; Corcoran, Michael F.; Petre, Rob +5 more
With the XMM-Newton and Chandra observatories, we detected two extremely embedded X-ray sources in the R Corona Australis (R CrA) star-forming core, near IRS 7. These sources, designated as XE and XW, have X-ray absorption columns of ~3×1023 cm-2 equivalent to AV~180 mag. They are associated w…
Chandra X-Ray Imaging of the Interacting Starburst Galaxy System NGC 7714/7715: Tidal Ultraluminous X-Ray Sources, Emergent Wind, and Resolved H II Regions
Struck, Curtis; Smith, Beverly J.; Nowak, Michael A.
We present high spatial resolution X-ray imaging data for the interacting galaxy pair NGC 7714/7715 (Arp 284) from the Chandra X-ray telescope. In addition to the unresolved starburst nucleus, a variable point source with LX~1040 ergs s-1 was detected 1.5" (270 pc) to the northwest of the nucleus, coincident with a…
Distribution of the Magnetic Flux in Elements of the Magnetic Field in Active Regions
Abramenko, V. I.; Longcope, D. W.
The unsigned magnetic flux content in the flux concentrations of two active regions is calculated by using a set of 248 high-resolution Solar and Heliospheric Observatory Michelson Doppler Imager magnetograms for each active region. Data for flaring active region NOAA 9077 (2000 July 14) and nonflaring active region NOAA 0061 (2002 August 9) were …