Norbert Schartel

  • Citations Per Year
Learn More
We present results of a systematic analysis of the XMM–Newton spectra of 40 quasars (QSOs) (z≤ 1.72) from the Palomar–Green (PG) Bright Quasar Survey sample (MB < −23). The sample includes 35 radio-quiet quasars (RQQs) and 5 radio-loud quasars (RLQs). The analysis of the spectra above 2 keV reveals that the hard X–ray continuum emission can be modeled with(More)
NASA's Chandra X-ray Observatory and the ESA's X-ray Multi-Mirror Mission (XMM-Newton) made their first observations ten years ago. The complementary capabilities of these observatories allow us to make high-resolution images and precisely measure the energy of cosmic X-rays. Less than 50 years after the first detection of an extrasolar X-ray source, these(More)
Now that gamma-ray bursts (GRBs) have been determined to lie at cosmological distances, their isotropic burst energies are estimated to be as high as 1054 erg (ref. 2), making them the most energetic phenomena in the Universe. The nature of the progenitors responsible for the bursts remains, however, elusive. The favoured models range from the merger of two(More)
XMM-Newton observations of seven QSOs are presented and the EPIC spectra analysed. Five of the AGN show evidence for Fe Kα emission, with three being slightly better fitted by lines of finite width; at the 99 per cent level they are consistent with being intrinsically narrow, though. The broad-band spectra can be well modelled by a combination of different(More)
The properties of the fluorescence Fe Kα emission lines of a sample of 38 quasars (QSOs) observed with XMM–Newton are studied. These objects are included in the optically selected sample from the Palomar–Green (PG) Bright Quasar Survey with an X–ray luminosity 1.3 × 10 43 <L 2−10 keV < 5.1 × 10 45 erg s −1 and z≤1.72. For each object in the sample, we(More)
Close to the celestial position of the QSO Ton S180 a bright X-ray source was detected by ROSAT during the all-sky survey. Pointed follow-up observations confirmed the positional coincidence of RX J0057.3–2222 and Ton S180. The X-ray radiation of the quasar is intensity variable on time scales of hours to days and years with amplitudes up to a factor of(More)
  • P. M. Rodŕıguez-Pascual, Norbert Schartel, W. Wamsteker, A. Pérez-Calpena
  • 1999
In this paper we outline the modifications introduced to the optimal extraction algorithms for IUE Low-Dispersion data under INES. A major modification has been the creation of new noise models for the three cameras, in order to improve the handling of very high and very low FN values. Other changes affect the background estimate, the extraction profile(More)
We identify the fading X-ray afterglow of GRB 001025A from XMM-Newton observations obtained 1.9–2.3 days, 2 years, and 2.5 years after the burst. The non-detection of an optical counterpart to an upper limit of R = 25.5, 1.20 days after the burst, makes GRB 001025A a " dark " burst. Based on the X-ray af-terglow spectral properties of GRB 001025A, we argue(More)
We report the detection of high-amplitude X-ray flaring of the AGN HE 1136-2304, which is accompanied by a strong increase in the flux of the broad Balmer lines, changing its Seyfert type from almost type 2 in 1993 down to 1.5 in 2014. HE 1136-2304 was detected by the XMM–Newton slew survey at >10 times the flux it had in the ROSAT all-sky survey, and(More)