W. Brinkmann - Academia.edu (original) (raw)

Papers by W. Brinkmann

Research paper thumbnail of X-ray variability of the Narrow Line Seyfert 1 Galaxy PKS 0558-504

Arxiv preprint astro-ph/ …, 2003

Research paper thumbnail of ROSAT detected quasars. II. (Brinkmann+ 1997)

We present the broad band, radio - to - X-ray, properties of a large sample of mostly previously ... more We present the broad band, radio - to - X-ray, properties of a large sample of mostly previously optically unidentified radio-loud X-ray sources from the correlation of a ROSAT All-Sky Survey source list with the 5GHz Green Bank Survey of the northern sky (RGB sample) which is one of the largest well-defined flux-limited surveys of AGN ever obtained. Further, the

Research paper thumbnail of Observation of soft X-ray emission from the supernova remnant G18.95 - 1.1

Astronomy and Astrophysics

Research paper thumbnail of XMM-Newton observations of the eastern jet of SS433

The radio supernova remnant W50 hosts at its center the peculiar galactic X-ray binary SS 433. It... more The radio supernova remnant W50 hosts at its center the peculiar galactic X-ray binary SS 433. It shows a central spherical structure with two `ears' which are supposed to be formed by the interaction of the precessing jets of SS 433 with the supernova shell. In two pointings in September/October 2004 for 30 ks each the eastern jet of SS

Research paper thumbnail of ROSAT HRI observation of the supernova remnant Kes 32 and the nearby radio pulsar PSR B1610-50

Astronomy and Astrophysics

Research paper thumbnail of Radio-loud galaxies in the ROSAT survey. IV. (Reich+, 2000)

Table 1 lists the results for 741 sources of Effelsberg radio observations together with the ROSA... more Table 1 lists the results for 741 sources of Effelsberg radio observations together with the ROSAT X-ray data and optical identifications as far as available. Table 2 lists 57 additional observations from 48 sources from Table 1, which were observed more than once. (2 data files).

Research paper thumbnail of The soft X-ray properties and the VLBI properties of AGN from the CJF sample : A search for correlations

All 293 AGN of the most recently completed VLBI survey of the Caltech-Jodrell Bank flat spectrum ... more All 293 AGN of the most recently completed VLBI survey of the Caltech-Jodrell Bank flat spectrum sample (hereafter CJF) have been observed in the ROSAT All-Sky survey and in part in pointed PSPC observations. We here summarize the radio properties, the soft X-ray properties for the complete CJF survey, and give a progress report on the search for correlations between the X-ray and VLBI properties for those sources with motion information (242 sources). Comparing the observed and the predicted X-ray flux by assuming the observed X-rays to be of inverse Compton origin, we compute the beaming or Doppler factor deltaIC for the CJF sources. We compare the Doppler factors with other beaming indicators derived from the VLBI observations, such as the value of the expansion velocity. In addition, we discuss a possible correlation between the complexity of the extended emission seen with the VLA (literature) and the X-ray flux density. AGN are our principal probes of the universe on large sca...

Research paper thumbnail of Recent X-ray Observations of Intermediate BL Lac Objects

The correlation of the ROSAT All-Sky Survey and the Green Bank 5GHz radio survey yielded a large ... more The correlation of the ROSAT All-Sky Survey and the Green Bank 5GHz radio survey yielded a large number of intermediate BL Lac objects, a new class of AGN which exhibits spectral energy distributions intermediate between the previously known classes of X-ray and radio-selected BL Lac objects. We report on recent ROSAT, ASCA and BeppoSAX observations of a few archetypal objects

Research paper thumbnail of Correlated X-ray to UV Variability in MCG-6-30-15

We used a ˜ 300 ks long XMM-Newton observation of MCG-6-30-15 to study the correlation between th... more We used a ˜ 300 ks long XMM-Newton observation of MCG-6-30-15 to study the correlation between the 0.2-10 keV X-ray and the 3000-4000 Å U bands. The light curves are well correlated with a time lag of τ_{max}˜ 160 ks where the U-band variations lead the variations in the X-ray band. This result gives evidence for Comptonisation scenarios where the X-rays are produced through Compton up-scattering of hard UV seed photons, as this process naturally predicts the observed soft U-band variations will precede similar flux variations in the X-rays. The length of the time lag favours models where the observed U band and seed photon emitting regions are connected by perturbations of the accretion flow traveling inwards through the disc affecting first the observed U-band emitting radii and then the innermost region where the bulk of the seed photons are expected to be produced. Finally, the absence of a positive correlation,where X-ray flux variations precede the U-band variations, indicates...

Research paper thumbnail of Doppler-shifted X-ray line emission from SS433

Monthly Notices of the Royal Astronomical Society, 1986

Research paper thumbnail of Optical and X-ray Monitoring of the NLS1 Galaxy Ark 564

Research paper thumbnail of ASCA observation of the infrared quasar IRAS 13349+2438

Astronomy and Astrophysics

We present ASCA observations of the infrared quasar IRAS 13349+2438. The object shows intensity v... more We present ASCA observations of the infrared quasar IRAS 13349+2438. The object shows intensity variations of a factor of two on time scales of a few hours without significant spectral changes. The 0.6-8keV X-ray spectrum can be fitted with a power law ({GAMMA}=2.40+/-0.04) and two Gaussian emission lines with rest frame line energies of E_l_~0.65 and E_l_~6.54keV. The average monochromatic flux at 1keV is comparable to that during the higher state of a previous ROSAT observation. The strong absorption feature at energies <1keV found in the ROSAT data could not be confirmed.

Research paper thumbnail of ROSAT detected quasars. II. (Yuan+ 1998)

We have compiled a sample of all radio-quiet quasars or quasars without radio detection from the ... more We have compiled a sample of all radio-quiet quasars or quasars without radio detection from the Veron-Cetty - Veron catalogue (1993, VV93, Cat. ) detected by ROSAT in the ALL-SKY SURVEY (RASS, Voges 1992, in Proc. of the ISY Conference `Space Science', ESA ISY-3, ESA Publications, p.9, See Cat. ), as targets of pointed observations, or as serendipitous sources from

Research paper thumbnail of X-ray/UV Correlation in MCG–6-30-15

ESO Astrophysics Symposia, 2005

ABSTRACT The connection between the UV and X-ray emission in AGN depends mainly on two processes:... more ABSTRACT The connection between the UV and X-ray emission in AGN depends mainly on two processes: Comptonisation of UV photons into the X-ray range and thermal reprocessing of X-rays into the UV band. Both processes introduce correlations between the light curves of these energy bands but predict opposite time lags. The study of the correlated variability in these bands can in principle determine which of the emission processes dominates in a given object. In this paper we study the variability of the narrow line Seyfert 1 galaxy MCG-6-30-15 using simultaneous X-ray and UV data obtained with XMM-Newton. A complete account on this work is given in [1].

Research paper thumbnail of The warm absorber in IRAS 13349+2438: dusty or not?

Astronomy & Astrophysics - ASTRON ASTROPHYS, 1999

IRAS 13349+2438 was the first quasar suggested to host a warm absorber with internal dust. We obt... more IRAS 13349+2438 was the first quasar suggested to host a warm absorber with internal dust. We obtained new HRI data for this object and derive constraints on the X-ray emitting region of IRAS 13349+2438 by investigating its X-ray extent and lightcurve. Rapid X-ray variability is detected with a factor of two change in count rate within one day and 20% variability within about three hours, which practically rules out any significant contribution of scattered X-rays. We present for the first time a detailed, self-consistent modeling of the ROSAT PSPC and ASCA spectrum of IRAS 13349+2438 in terms of a warm absorber including dust. It turns out that both a dust-free and a dusty single-component warm absorber fail to explain the ROSAT, ASCA, and optical data simultaneously. We discuss possible explanations such as a variable and/or complex warm absorber, a variable soft X-ray continuum and instrumental effects.

Research paper thumbnail of Multiwavelength Monitoring of the BL Lac Object PKS 2155-304. I. IUE Observations

... Edelson, R.; Koratkar, A.; Madejski, G.; Pian, E.; Pike, G.; Reichert, G.; Treves, A.; Wamste... more ... Edelson, R.; Koratkar, A.; Madejski, G.; Pian, E.; Pike, G.; Reichert, G.; Treves, A.; Wamsteker, W.; Bohlin, R.; Brinkmann, W.; Chiappetti, L.; Courvoisier, T.; Filippenko, AV; Fink, H.; George, IM; Kondo, Y.; Krolik, J.; O'Brien, P.; Shull ... Edited by Piero Benvenuti and Ethan J. Schreier. ...

Research paper thumbnail of The RGB Sample of Intermediate BL Lacertae Objects

The Astrophysical Journal, 1999

Research paper thumbnail of Long‐Term X‐Ray Spectral Variability of the Radio‐Loud Narrow‐Line Seyfert 1 Galaxy PKS 0558−504

The Astrophysical Journal, 2007

Research paper thumbnail of Multiwavelength Monitoring of the Narrow‐Line Seyfert 1 Galaxy Arakelian 564. II. Ultraviolet Continuum and Emission‐Line Variability

The Astrophysical Journal, 2001

Research paper thumbnail of An ASCA GIS spectrum of S5 0014+813 AT Z = 3.384

The Astrophysical Journal, 1994

... 405 Serlemitsos, P., Yaqoob, T., Ricker, G., Woo, J., Kunieda, H., Terashima, Y., & Iwasa... more ... 405 Serlemitsos, P., Yaqoob, T., Ricker, G., Woo, J., Kunieda, H., Terashima, Y., & Iwasawa, K. 1994, PASJ, 46, L43 Shastri, P., Wilkes, BJ, Elvis, M., & McDowell, JC 1993, ApJ, 410,29 Stark, AA, Gammie, CF, Wilson, RW, Bally, J., Linke, R., Heiles, C., & Hurwitz, M. 1989, ApJS ...

Research paper thumbnail of X-ray variability of the Narrow Line Seyfert 1 Galaxy PKS 0558-504

Arxiv preprint astro-ph/ …, 2003

Research paper thumbnail of ROSAT detected quasars. II. (Brinkmann+ 1997)

We present the broad band, radio - to - X-ray, properties of a large sample of mostly previously ... more We present the broad band, radio - to - X-ray, properties of a large sample of mostly previously optically unidentified radio-loud X-ray sources from the correlation of a ROSAT All-Sky Survey source list with the 5GHz Green Bank Survey of the northern sky (RGB sample) which is one of the largest well-defined flux-limited surveys of AGN ever obtained. Further, the

Research paper thumbnail of Observation of soft X-ray emission from the supernova remnant G18.95 - 1.1

Astronomy and Astrophysics

Research paper thumbnail of XMM-Newton observations of the eastern jet of SS433

The radio supernova remnant W50 hosts at its center the peculiar galactic X-ray binary SS 433. It... more The radio supernova remnant W50 hosts at its center the peculiar galactic X-ray binary SS 433. It shows a central spherical structure with two `ears' which are supposed to be formed by the interaction of the precessing jets of SS 433 with the supernova shell. In two pointings in September/October 2004 for 30 ks each the eastern jet of SS

Research paper thumbnail of ROSAT HRI observation of the supernova remnant Kes 32 and the nearby radio pulsar PSR B1610-50

Astronomy and Astrophysics

Research paper thumbnail of Radio-loud galaxies in the ROSAT survey. IV. (Reich+, 2000)

Table 1 lists the results for 741 sources of Effelsberg radio observations together with the ROSA... more Table 1 lists the results for 741 sources of Effelsberg radio observations together with the ROSAT X-ray data and optical identifications as far as available. Table 2 lists 57 additional observations from 48 sources from Table 1, which were observed more than once. (2 data files).

Research paper thumbnail of The soft X-ray properties and the VLBI properties of AGN from the CJF sample : A search for correlations

All 293 AGN of the most recently completed VLBI survey of the Caltech-Jodrell Bank flat spectrum ... more All 293 AGN of the most recently completed VLBI survey of the Caltech-Jodrell Bank flat spectrum sample (hereafter CJF) have been observed in the ROSAT All-Sky survey and in part in pointed PSPC observations. We here summarize the radio properties, the soft X-ray properties for the complete CJF survey, and give a progress report on the search for correlations between the X-ray and VLBI properties for those sources with motion information (242 sources). Comparing the observed and the predicted X-ray flux by assuming the observed X-rays to be of inverse Compton origin, we compute the beaming or Doppler factor deltaIC for the CJF sources. We compare the Doppler factors with other beaming indicators derived from the VLBI observations, such as the value of the expansion velocity. In addition, we discuss a possible correlation between the complexity of the extended emission seen with the VLA (literature) and the X-ray flux density. AGN are our principal probes of the universe on large sca...

Research paper thumbnail of Recent X-ray Observations of Intermediate BL Lac Objects

The correlation of the ROSAT All-Sky Survey and the Green Bank 5GHz radio survey yielded a large ... more The correlation of the ROSAT All-Sky Survey and the Green Bank 5GHz radio survey yielded a large number of intermediate BL Lac objects, a new class of AGN which exhibits spectral energy distributions intermediate between the previously known classes of X-ray and radio-selected BL Lac objects. We report on recent ROSAT, ASCA and BeppoSAX observations of a few archetypal objects

Research paper thumbnail of Correlated X-ray to UV Variability in MCG-6-30-15

We used a ˜ 300 ks long XMM-Newton observation of MCG-6-30-15 to study the correlation between th... more We used a ˜ 300 ks long XMM-Newton observation of MCG-6-30-15 to study the correlation between the 0.2-10 keV X-ray and the 3000-4000 Å U bands. The light curves are well correlated with a time lag of τ_{max}˜ 160 ks where the U-band variations lead the variations in the X-ray band. This result gives evidence for Comptonisation scenarios where the X-rays are produced through Compton up-scattering of hard UV seed photons, as this process naturally predicts the observed soft U-band variations will precede similar flux variations in the X-rays. The length of the time lag favours models where the observed U band and seed photon emitting regions are connected by perturbations of the accretion flow traveling inwards through the disc affecting first the observed U-band emitting radii and then the innermost region where the bulk of the seed photons are expected to be produced. Finally, the absence of a positive correlation,where X-ray flux variations precede the U-band variations, indicates...

Research paper thumbnail of Doppler-shifted X-ray line emission from SS433

Monthly Notices of the Royal Astronomical Society, 1986

Research paper thumbnail of Optical and X-ray Monitoring of the NLS1 Galaxy Ark 564

Research paper thumbnail of ASCA observation of the infrared quasar IRAS 13349+2438

Astronomy and Astrophysics

We present ASCA observations of the infrared quasar IRAS 13349+2438. The object shows intensity v... more We present ASCA observations of the infrared quasar IRAS 13349+2438. The object shows intensity variations of a factor of two on time scales of a few hours without significant spectral changes. The 0.6-8keV X-ray spectrum can be fitted with a power law ({GAMMA}=2.40+/-0.04) and two Gaussian emission lines with rest frame line energies of E_l_~0.65 and E_l_~6.54keV. The average monochromatic flux at 1keV is comparable to that during the higher state of a previous ROSAT observation. The strong absorption feature at energies <1keV found in the ROSAT data could not be confirmed.

Research paper thumbnail of ROSAT detected quasars. II. (Yuan+ 1998)

We have compiled a sample of all radio-quiet quasars or quasars without radio detection from the ... more We have compiled a sample of all radio-quiet quasars or quasars without radio detection from the Veron-Cetty - Veron catalogue (1993, VV93, Cat. ) detected by ROSAT in the ALL-SKY SURVEY (RASS, Voges 1992, in Proc. of the ISY Conference `Space Science', ESA ISY-3, ESA Publications, p.9, See Cat. ), as targets of pointed observations, or as serendipitous sources from

Research paper thumbnail of X-ray/UV Correlation in MCG–6-30-15

ESO Astrophysics Symposia, 2005

ABSTRACT The connection between the UV and X-ray emission in AGN depends mainly on two processes:... more ABSTRACT The connection between the UV and X-ray emission in AGN depends mainly on two processes: Comptonisation of UV photons into the X-ray range and thermal reprocessing of X-rays into the UV band. Both processes introduce correlations between the light curves of these energy bands but predict opposite time lags. The study of the correlated variability in these bands can in principle determine which of the emission processes dominates in a given object. In this paper we study the variability of the narrow line Seyfert 1 galaxy MCG-6-30-15 using simultaneous X-ray and UV data obtained with XMM-Newton. A complete account on this work is given in [1].

Research paper thumbnail of The warm absorber in IRAS 13349+2438: dusty or not?

Astronomy & Astrophysics - ASTRON ASTROPHYS, 1999

IRAS 13349+2438 was the first quasar suggested to host a warm absorber with internal dust. We obt... more IRAS 13349+2438 was the first quasar suggested to host a warm absorber with internal dust. We obtained new HRI data for this object and derive constraints on the X-ray emitting region of IRAS 13349+2438 by investigating its X-ray extent and lightcurve. Rapid X-ray variability is detected with a factor of two change in count rate within one day and 20% variability within about three hours, which practically rules out any significant contribution of scattered X-rays. We present for the first time a detailed, self-consistent modeling of the ROSAT PSPC and ASCA spectrum of IRAS 13349+2438 in terms of a warm absorber including dust. It turns out that both a dust-free and a dusty single-component warm absorber fail to explain the ROSAT, ASCA, and optical data simultaneously. We discuss possible explanations such as a variable and/or complex warm absorber, a variable soft X-ray continuum and instrumental effects.

Research paper thumbnail of Multiwavelength Monitoring of the BL Lac Object PKS 2155-304. I. IUE Observations

... Edelson, R.; Koratkar, A.; Madejski, G.; Pian, E.; Pike, G.; Reichert, G.; Treves, A.; Wamste... more ... Edelson, R.; Koratkar, A.; Madejski, G.; Pian, E.; Pike, G.; Reichert, G.; Treves, A.; Wamsteker, W.; Bohlin, R.; Brinkmann, W.; Chiappetti, L.; Courvoisier, T.; Filippenko, AV; Fink, H.; George, IM; Kondo, Y.; Krolik, J.; O'Brien, P.; Shull ... Edited by Piero Benvenuti and Ethan J. Schreier. ...

Research paper thumbnail of The RGB Sample of Intermediate BL Lacertae Objects

The Astrophysical Journal, 1999

Research paper thumbnail of Long‐Term X‐Ray Spectral Variability of the Radio‐Loud Narrow‐Line Seyfert 1 Galaxy PKS 0558−504

The Astrophysical Journal, 2007

Research paper thumbnail of Multiwavelength Monitoring of the Narrow‐Line Seyfert 1 Galaxy Arakelian 564. II. Ultraviolet Continuum and Emission‐Line Variability

The Astrophysical Journal, 2001

Research paper thumbnail of An ASCA GIS spectrum of S5 0014+813 AT Z = 3.384

The Astrophysical Journal, 1994

... 405 Serlemitsos, P., Yaqoob, T., Ricker, G., Woo, J., Kunieda, H., Terashima, Y., & Iwasa... more ... 405 Serlemitsos, P., Yaqoob, T., Ricker, G., Woo, J., Kunieda, H., Terashima, Y., & Iwasawa, K. 1994, PASJ, 46, L43 Shastri, P., Wilkes, BJ, Elvis, M., & McDowell, JC 1993, ApJ, 410,29 Stark, AA, Gammie, CF, Wilson, RW, Bally, J., Linke, R., Heiles, C., & Hurwitz, M. 1989, ApJS ...