Search Publications
Hard X-ray bursts detected by the IBIS telescope onboard the INTEGRAL observatory in 2003 2004
Sunyaev, R. A.; Grebenev, S. A.; Chelovekov, I. V.
All of the observations performed with the IBIS telescope onboard the INTEGRAL observatory during the first one and a half years of its in-orbit operation (from February 10, 2003, through July 2, 2004) have been analyzed to find X-ray bursts. The time history of the IBIS/ISGRI total count rate in the energy range 15-25 keV revealed 1077 bursts of …
Testing Rotational Mixing Predictions with New Boron Abundances in Main-Sequence B-Type Stars
Lambert, D. L.; Mendel, J. T.; Venn, K. A. +2 more
New boron abundances for seven main-sequence B-type stars are determined from HST STIS spectroscopy around the B III 2066 Å line. Boron abundances provide a unique and critical test of stellar evolution models that include rotational mixing, since boron is destroyed in the surface layers of stars through shallow mixing long before other elements a…
The Water Vapor Abundance in Orion KL Outflows
Cernicharo, José; Viti, Serena; Barlow, Michael J. +7 more
We present the detection and modeling of more than 70 far-IR pure rotational lines of water vapor, including the 18O and 17O isotopologues, toward Orion KL. Observations were performed with the Long Wavelength Spectrometer in Fabry-Pérot mode (λ/Δλ~6800-9700) on board the Infrared Space Observatory between ~43 and 197 µ…
Luminosity functions and star formation rates at z ∼ 6 10: Galaxy buildup in the reionization age
Bouwens, Rychard; Illingworth, Garth
HST ACS and NICMOS data are now of sufficient depth and areal coverage to place strong constraints on the formation and evolution of galaxies during the first 1-2 Gyrs of the universe. Of particular interest are galaxies at z ∼ 6 since they represent the earliest epoch accessible to current high-efficiency optical instrumentation. To this end, we …
Multiwavelength Monitoring of the Dwarf Seyfert 1 Galaxy NGC 4395. III. Optical Variability and X-Ray/UV/Optical Correlations
O'Neill, Paul M.; Kaspi, Shai; Laor, Ari +11 more
We present optical observations of the low-luminosity Seyfert 1 nucleus of NGC 4395, as part of a multiwavelength reverberation-mapping program. Observations were carried out over two nights in 2004 April at Lick, Wise, and Kitt Peak Observatories. We obtained V- and B-band photometry, and spectra over the range 3500-6800 Å. Simultaneous Hubble Sp…
Globular cluster systems of six shell galaxies
Peletier, R. F.; Balcells, M.; Valentijn, E. A. +2 more
Context: .Shells in Elliptical Galaxies are faint, sharp-edged features, believed to provide evidence of a recent (∼ 0.5 - 2 × 109 years ago) merger event. We analyse the Globular Cluster (GC) systems of six shell elliptical galaxies, to examine the effects of mergers upon the GC formation history.
Aims: .We examine the colour dist…
Magnetoacoustic wave propagation in off-limb polar regions
Doyle, J. G.; Banerjee, D.; O'Shea, E.
Aims.To find evidence of magnetoacoustic waves in off-limb polar regions.
Methods: .Using temporal series data from the Coronal Diagnostic Spectrometer (CDS) on SOHO, we study oscillations found in radiant flux and velocity measurements from transition region and coronal spectral lines. We use Fourier techniques to measure phase delays between…
Titan's planetary boundary layer structure at the Huygens landing site
Colombatti, Giacomo; Tokano, Tetsuya; Ferri, Francesca +2 more
Huygens Atmospheric Structure Instrument (HASI) for the first time performed an in situ measurement of the thermal structure in Titan's atmosphere with a vertical resolution sufficient to analyze the planetary boundary layer (PBL). The vertical potential temperature profile reveals the presence of a weakly convective PBL, with a surface layer thic…
Magnetospheric energy budget during huge geomagnetic activity using Cluster and ground-based data
Buchert, S.; Vaivads, A.; Lu, G. +2 more
The Cluster spacecraft crossed the magnetopause at the duskward flank of the tail while the European Incoherent Scatter (EISCAT) radars and magnetometers observed the ionosphere during a sequence of intense substorm-like geomagnetic activity in October 2003. We attempt to estimate the local and global energy flow from the magnetosheath into the ma…
Spatially Resolved X-Ray Spectroscopy of Vela Shrapnel A
Katsuda, S.; Tsunemi, H.
We present detailed X-ray spectroscopy of Vela shrapnel A with the XMM-Newton satellite. Vela shrapnel A is one of several protrusions identified as bullets from the Vela supernova explosion. The XMM-Newton image shows that shrapnel A consists of a bright knot and a faint trailing wake. We extracted spectra from various regions, finding a prominen…