Search Publications
INTEGRAL SPI Observations of Cygnus X-1 in the Soft State: What about the Jet Contribution in Hard X-Rays?
Jourdain, E.; Roques, J. P.; Chauvin, M.
During the first 7 yr of the INTEGRAL mission (2003-2009), Cyg X-1 has essentially been detected in its hard state (HS), with some incursions in intermediate HSs. This long, spectrally stable period allowed in particular the measurement of the polarization of the high-energy component that has long been observed above 200 keV in this peculiar obje…
Expected number of supergiant fast X-ray transients in the Milky Way
Santangelo, A.; Ducci, L.; Romano, P. +2 more
In the past fifteen years a new generation of X-ray satellites led to the discovery of a subclass of high-mass X-ray binaries (HMXBs) with supergiant companions and a peculiar transient behaviour: supergiant fast X-ray transients (SFXTs). We calculate the expected number of Galactic SFXTs for the first time, using two different statistical approac…
Scaling Relations and X-Ray Properties of Moderate-luminosity Galaxy Clusters from 0.3 < z < 0.6 with XMM-Newton
Donahue, Megan; Conselice, Christopher J.; Hoekstra, Henk +4 more
We present new X-ray temperatures and improved X-ray luminosity estimates for 15 new and archival XMM-Newton observations of galaxy clusters at intermediate redshift with mass and luminosities near the galaxy group/cluster division ({M}2500 < 2.4 × 1014 h70-1 {M}_⊙, L < 2 × 1044 erg s
The global vortex analysis of Jupiter and Saturn based on Cassini Imaging Science Subsystem
Li, Liming; Jiang, Xun; Trammell, Harold Justin +3 more
Presented in this manuscript are observations exploring vortices with diameters larger than 1000 km on Jupiter and Saturn. These images are taken from the Imaging Science Subsystem onboard the Cassini Spacecraft. The analyses of Saturn's vortices show that there are significantly more vortices in the Southern Hemisphere (SH) than in the Northern H…
Automated Detection, Characterization, and Tracking of Sunspots from SoHO/MDI Continuum Images
Mathew, Shibu K.; Goel, Suruchi
We describe a procedure for automated detection of sunspots from SoHO/MDI full-disk continuum images. The MDI Level-1.8 continuum images were first corrected for the limb darkening and stray light, and then were flat-fielded. Sunspots were extracted using a newly developed automated sunspot detection procedure, which is based on the level set, nam…
Steadily Increasing Star Formation Rates in Galaxies Observed at 3 <~ z <~ 5 in the CANDELS/GOODS-S Field
Ferguson, Henry C.; Giavalisco, Mauro; Somerville, Rachel S. +3 more
We investigate the star formation histories (SFHs) of high redshift (3 <~ z <~ 5) star-forming galaxies selected based on their rest-frame ultraviolet (UV) colors in the CANDELS/GOODS-S field. By comparing the results from the spectral-energy-distribution-fitting analysis with two different assumptions about the SFHs—i.e., exponentially decl…
Upper limits to interstellar NH+ and para-NH2- abundances. Herschel-HIFI observations towards Sgr B2 (M) and G10.6-0.4 (W31C)
Menten, K. M.; Persson, C. M.; Lis, D. C. +12 more
The understanding of interstellar nitrogen chemistry has improved significantly with recent results from the Herschel Space Observatory. To set even better constraints, we report here on deep searches for the NH+ ground state rotational transition J = 1.5-0.5 of the 2Π1/2 lower spin ladder, with fine-structure tran…
Cluster observations of the substructure of a flux transfer event: analysis of high-time-resolution particle data
Dandouras, I.; Fazakerley, A. N.; André, M. +5 more
Flux transfer events (FTEs) are signatures of transient reconnection at the dayside magnetopause, transporting flux from the dayside of the magnetosphere into the magnetotail lobes. They have previously been observed to contain a combination of magnetosheath and magnetospheric plasma. On 12 February 2007, the four Cluster spacecraft were widely se…
HST optical polarimetry of the Vela pulsar and nebula
Mignani, R. P.; Moran, P.; Shearer, A.
Polarization measurements of pulsars offer a unique insight into the geometry of the emission regions in the neutron star magnetosphere. Therefore, they provide observational constraints on the different models proposed for the pulsar emission mechanisms. Optical polarization data of the Vela pulsar was obtained from the Hubble Space Telescope (HS…
The host galaxy and Fermi-LAT counterpart of HESS J1943+213
van der Wel, A.; Peter, D.; Domainko, W. +2 more
Context. The very-high energy (VHE, E> 100 GeV) gamma-ray sky shows diverse Galactic and extragalactic source populations. For some sources the astrophysical object class could not be identified so far.
Aims: The nature (Galactic or extragalactic) of the VHE gamma-ray source HESS J1943+213 is explored. We specifically investigate the propo…