Search Publications
The pulsed X-ray light curves of the isolated neutron star RBS1223
Haberl, F.; Motch, C.; Schwope, A. D. +1 more
We present a multi-epoch spectral and timing analysis of the isolated neutron star RBS1223. New XMM-Newton data obtained in January 2004 confirm the spin period to be twice as long as previously thought, P_spin = 10.31 s. The combined ROSAT, Chandra, and XMM-Newton data (6 epochs) give, contrary to earlier findings, no clear indication of a spin e…
XMM-Newton detection of hot gas in the Eskimo Nebula: Shocked stellar wind or collimated outflows?
Gruendl, R. A.; Chu, Y. -H.; Guerrero, M. A. +1 more
The Eskimo Nebula (NGC 2392) is a double-shell planetary nebula (PN) known for the exceptionally large expansion velocity of its inner shell, ∼90 km s-1, and the existence of a fast bipolar outflow with a line-of-sight expansion velocity approaching 200 km s-1. We have obtained XMM-Newton observations of the Eskimo and detect…
Intergalactic HeII absorption towards QSO 1157+3143
Reimers, D.; Hagen, H. -J.; Jakobsen, P. +3 more
We report the discovery of a further line of sight allowing detection of He II Lyα absorption by the intergalactic medium. A HST/STIS survey of 32 bright z ∼ 3 quasars selected from the Hamburg Quasar Surveys yielded one detection toward QSO 1157+3143 (z ∼ 3, B ≃ 17). A 10 orbit follow-up spectrum reveals a UV spectrum significantly suppressed by …
Identification of 8 INTEGRAL hard X-ray sources with Chandra
Sunyaev, R.; Revnivtsev, M.; Sazonov, S. +2 more
We report the results of identification of 8 hard X-ray sources discovered by the INTEGRAL observatory during the ongoing all-sky survey. These sources have been observed by Chandra. In 6 cases a bright X-ray source was found within the INTEGRAL localization region, which permitted to unambiguously identify 5 of the objects with nearby galaxies, i…
The 1-50 keV spectral and timing analysis of IGR J18027-2016: an eclipsing, high mass X-ray binary
Hill, A. B.; Knigge, C.; Walter, R. +9 more
We report the association of the INTEGRAL source IGR J18027-2016 with the BeppoSAX source SAX J1802.7-2017. IGR J18027-2016 is seen to be a weak, persistent source by the IBIS/ISGRI instrument on board INTEGRAL with an average source count rate of 0.58 counts s-1 ( 6.4 mCrab) in the 20-40 keV band. Timing analysis performed on the ISGRI…
First VLTI/MIDI observations of a Be star: Alpha Arae
Meilland, A.; Robbe-Dubois, S.; Domiciano de Souza, A. +12 more
We present the first VLTI/MIDI observations of the Be star alpha Ara (HD 158 427), showing a nearly unresolved circumstellar disk in the N band. The interferometric measurements made use of the UT1 and UT3 telescopes. The projected baselines were 102 and 74 meters with position angles of 7 ° and 55°, respectively. These measurements put an upper l…
The supermassive black hole in the Seyfert 2 galaxy NGC 5252
Marconi, A.; Capetti, A.; Axon, D. +1 more
We present results from HST/STIS long-slit spectroscopy of the gas motions in the nuclear region of the Seyfert 2 galaxy NGC 5252. The observed velocity field is consistent with gas in regular rotation with superposed localized patches of disturbed gas. The dynamics of the circumnuclear gas can be accurately reproduced by adding to the stellar mas…
Discovery of two M 32 twins in Abell 1689
Infante, L.; Blakeslee, J. P.; Hilker, M. +5 more
The M 31 satellite galaxy M 32 has long been considered an object of unique properties, being the most extreme example of the very rare compact elliptical galaxy class. Here we present the spectroscopic discovery of two M 32 twins in the massive galaxy cluster Abell 1689. As these objects are so rare, this is an important step towards a better und…
On the X-ray emission of z ∼2 radio galaxies: IC scattering of the CMB and no evidence for fully-formed potential wells
Pentericci, L.; Röttgering, H. J. A.; Miley, G. K. +3 more
We present the results of 20 ks Chandra observations for each of 5 radio galaxies in the redshift range 2.0<z<2.6. The goals were to (i) study the nature of their non-thermal X-ray emission; (ii) investigate the presence and amount of hot gas; and (iii) look for active galactic nuclei (AGN) overdensities in fields around high redshift radio …
The host galaxy/AGN connection in nearby early-type galaxies. Sample selection and hosts brightness profiles
Capetti, A.; Balmaverde, B.
This is the first of a series of three papers exploring the connection between the multiwavelength properties of AGNs in nearby early-type galaxies and the characteristics of their hosts. We selected two samples, both with high resolution 5 GHz VLA observations available and providing measurements down to 1 mJy level, reaching radio-luminosities a…