Search Publications
Unveiling the nature of INTEGRAL objects through optical spectroscopy. IX. Twenty two more identifications, and a glance into the far hard X-ray Universe
Palazzi, E.; Minniti, D.; Masetti, N. +14 more
Since its launch in October 2002, the INTEGRAL satellite has revolutionized our knowledge of the hard X-ray sky thanks to its unprecedented imaging capabilities and source detection positional accuracy above 20 keV. Nevertheless, many of the newly-detected sources in the INTEGRAL sky surveys are of unknown nature. The combined use of available inf…
Properties of the Intracluster Medium of Abell 3667 Observed with Suzaku XIS
Nakazawa, Kazuhiro; Ohashi, Takaya; Kaastra, Jelle +4 more
We observed the northwest region of the cluster of galaxies Abell 3667 with the Suzaku XIS instrument. The temperature and surface brightness of the intracluster medium were measured up to the virial radius (r200 ∼ 2.3 Mpc). The radial temperature profile is flatter than the average profile for other clusters until the radius reaches th…
Photometry and Photometric Redshift Catalogs for the Lockman Hole Deep Field
Lutz, D.; Burwitz, V.; Salvato, M. +9 more
We present broadband photometry and photometric redshifts for 187,611 sources located in ~0.5 deg2 in the Lockman Hole area. The catalog includes 388 X-ray-detected sources identified with the very deep XMM-Newton observations available for an area of 0.2 deg2. The source detection was performed on the R c-, z'-, a…
It's Alive! The Supernova Impostor 1961V
Van Dyk, Schuyler D.; Matheson, Thomas
Reports of the death of the precursor of supernova (SN) 1961V in NGC 1058 are exaggerated. Consideration of the best astrometric data shows that the star, known as "Object 7," lies at the greatest proximity to SN 1961V and is the likely survivor of the "SN impostor" super-outburst. SN 1961V does not coincide with a neighboring radio source and is …
Oxygen and hydrogen ion abundance in the near-Earth magnetosphere: Statistical results on the response to the geomagnetic and solar wind activity conditions
Dandouras, I.; Daly, P. W.; Kistler, L. M. +4 more
The composition of ions plays a crucial role for the fundamental plasma properties in the terrestrial magnetosphere. We investigate the oxygen-to-hydrogen ratio in the near-Earth magnetosphere from -10 RE < XGSE < 10 RE. The results are based on seven years of ion flux measurements in the energy range ∼10 keV…
Composition and structures of the subsurface in the vicinity of Valles Marineris as revealed by central uplifts of impact craters
Quantin, Cathy; Flahaut, Jessica; Clenet, Harold +2 more
Despite recent efforts from space exploration to sound the martian subsurface with RADAR, the structure of the martian subsurface is still unknown. Major geologic contacts or discontinuities inside the martian crust have not been revealed. Another way to analyze the subsurface is to study rocks that have been exhumed from depth by impact processes…
Modelling the very high energy flare of 3C 279 using one-zone leptonic model
Godambe, S.; Sahayanathan, S.
We model the simultaneous observations of the flat-spectrum radio quasar 3C 279 at radio, optical, X-ray and very high energy (VHE) gamma-ray energies during 2006 flare using a simple one-zone leptonic model. We consider synchrotron emission due to cooling of a non-thermal electron distribution in an equipartition magnetic field and inverse Compto…
The velocity dispersion and mass function of the outer halo globular cluster Palomar 4
Djorgovski, S. G.; Grebel, Eva K.; Côté, Patrick +5 more
We obtained precise line-of-sight radial velocities of 23 member stars of the remote halo globular cluster Palomar 4 (Pal 4) using the High Resolution Echelle Spectrograph at the Keck I telescope. We also measured the mass function of the cluster down to a limiting magnitude of V∼ 28 mag using archival Hubble Space Telescope/Wide Field Planetary C…
Can solar wind viscous drag account for coronal mass ejection deceleration?
Subramanian, Prasad; Lara, Alejandro; Borgazzi, Andrea
The forces acting on solar Coronal Mass Ejections (CMEs) in the interplanetary medium have been evaluated so far in terms of an empirical drag coefficient CD ∼ 1 that quantifies the role of the aerodynamic drag experienced by a typical CME due to its interaction with the ambient solar wind. We use a microphysical prescription for viscos…
Physical Properties of the Narrow-line Region of Low-mass Active Galaxies
Ho, Luis C.; Barth, Aaron J.; Greene, Jenny E. +1 more
We present spectroscopic observations of 27 active galactic nuclei (AGNs) with some of the lowest black hole (BH) masses known. We use the high spectral resolution and small aperture of our Keck data, taken with the Echellette Spectrograph and Imager, to isolate the narrow-line regions (NLRs) of these low-mass BHs. We investigate their emission-li…