Search Publications

Q2237+0305 in X-rays: spectra and variability with XMM-Newton

Vignali, C.; Palumbo, G. G. C.; Fedorova, E. V. +1 more

Aims: X-ray observations of gravitationally lensed quasars may allow us to probe the inner structure of the central engine of a quasar. Observations of Q2237+0305 (Einstein Cross) in X-rays may be used to constrain the inner structure of the X-ray emitting source.
Methods: Here we analyze the XMM-Newton observation of the quasar in the gravita…

A Search for the Optical Counterpart to the Magnetar CXOU J010043.1-721134

van Kerkwijk, M. H.; Durant, M.

After our tentative detection of an optical counterpart to CXOU J010043.1-721134 from archival Hubble Space Telescope (HST) imaging, we have followed up with further images in four bands. Unfortunately, the source originally identified is not confirmed. We provide deep photometric limits in four bands and accurate photometry of field stars around …

The structure of the AD diagram for the hyades cluster

Vereshchagin, S. V.; Reva, V. G.; Chupina, N. V.

The Hyades Cluster is used to analyze details of the AD-diagram method developed in our earlier works and applied to the corona of the Ursa Major stream. Hipparcos data are used to analyze the kinematics of the Hyades Cluster and determine its apex. Evidence for rotation of the cluster is presented.

Revisiting the Local Kinematics of the Milky Way using the New Hipparcos Data

Zhu, Zi; Yuan, Fang-Ting; Kong, Da-Li

With the new Hipparcos data recently released, we reexamine the kinematics in the solar neighborhood. Two different populations of objects, namely the thin-disk O-B5 stars and the thick-disk K-M giants, are selected for tracing the kinematical parameters of the Galaxy. Using a 3-D kinematical model, the components of the solar motion and the Oort …

Occurrence and source characteristics of the high-latitude components of Jovian broadband kilometric radiation

Morioka, Akira; Tsuchiya, Fuminori; Misawa, Hiroaki +2 more

Ulysses had a "distant encounter" with Jupiter when it was within 0.8 AU of the planet during February, 2004. The passage of the spacecraft was from north to south, and observations of the Jovian radio waves were carried out for a few months from high to low latitudes (+80° to +10°) of Jupiter. The statistical study performed during this "distant …

Suzaku Observation of the Anomalous X-Ray Pulsar CXOU J164710.2--455216

Dotani, Tadayasu; Enoto, Teruaki; Kokubun, Motohide +11 more

A Suzaku TOO observation of CXOU J164710.2-455216 was performed on 2006 September 23-24 for a net exposure of 38.8ks. Pulsations were clearly detected in the XIS light curves with a pulse period of 10.61063(2)s. The XIS pulse profile is found to be highly non-sinusoidal. It shows 3 peaks of different amplitudes with an RMS fractional amplitude of …

The changing face of Titan

Lorenz, Ralph D.

Long-Term Study of Active Spacecraft Potential Control

Eriksson, A. I.; Lindqvist, P. -A.; Torkar, K. +1 more

On the possibility of microbiota transfer from Venus to Earth

Wickramasinghe, N. C.; Wickramasinghe, J. T.

The possibility of the clouds of Venus providing habitats for extremophilic microorganisms has been discussed for several decades. We show here that the action of the solar wind leads to erosion of parts of the atmosphere laden with aerosols and putative microorganisms, forming a comet-like tail in the antisolar direction. During inferior conjunct…

An Overdensity of i-Dropouts among a Population of Excess Field Objects in the Virgo Cluster

Hathi, Nimish P.; Yan, Haojing; Windhorst, Rogier A.

Using a set of deep imaging data obtained by the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST) shortly after its deployment, Yan, Windhorst, & Cohen found a large number of F775W-band dropouts (i-dropouts), which are consistent with being galaxies at z ≈ 6. The surface density of i-dropouts thus derived, however, is an …