Scientific Commons: A. J. J. Raassen

XMM-Newton observations of zeta Orionis (O9.7 Ib): A collisional ionization equilibrium model (2009)

Raassen, A.J.J., Hucht, K.A. Van Der, Miller, N.A., Cassinelli, J.P.

We present the analysis of XMM-Newton observations of zeta Orionis. The analysis is based on fitting to the total spectrum as well as diagnostics of individual line.

XMM-Newton observations of Zeta Orionis (O9.7 Ib): A Collisional Ionization Equilibrium model (2008)

Raassen, A. J. J., Van Der Hucht, K. A., Miller, N. A., Cassinelli, J. P.

We present XMM-Newton observations of the O supergiant Zeta Orionis (O9.7 Ib). The spectra are rich in emission lines over a wide range of ionization stages. The RGS-spectra show for the first time...

XMM-Newton observations of zeta Orionis (O9.7 Ib): A collisional ionization equilibrium model (2008)

Raassen, A.J.J., Hucht, K.A. Van Der, Miller, N.A., Cassinelli, J.P.

We present XMM-Newton observations of the O supergiant zeta Orionis (O9.7 Ib). The spectra are rich in emission lines over a wide range of ionization stages. The RGS spectra show for the first time...

XMM-Newton Studies of the Wolf-Rayet Colliding-Wind Binaries WR 25 (WN6h+O4f) and WR 11 (WC8+O7.5III) (2008)

Hucht, K.A. Van Der, Raassen, A.J.J., Mewe, R., Antokhin, I.I., Rauw, G., Vreux, J.M., ...

We report the analysis of high- and medium-resolution X-ray spectra of the Wolf-Rayet (WR) objects WR25 (HD93162, WN6h+O4f) and WR11 (gamma2 Velorum, WC8+O7.5III, P =78.53 d), obtained with the...

X-Ray Spectra of Early-type Stars Observed with CHANDRA and XMM-Newton} (2008)

Raassen, A.J.J.

In this paper I will discuss the temperature, density, and abundance diagnostic tools for X-ray emitting plasmas around early type stars. The methods used are based on individual line fitting,...

XMM-Newton observations of zeta Orionis (O9.7 Ib) : a collisional ionization equilibrium model (2007)

Raassen, A. J. J., Hucht, K. A. Van Der, Miller, N. A., Cassinelli, Joe P.

We present the analysis of XMM-Newton observations of ζ Orionis. The analysis is based on fitting to the total spectrum as well as diagnostics of individual line.

XMM-Newton observations of zeta Orionis (O9.7 Ib) : a collisional ionization equilibrium model (2007)

Raassen, A. J. J., Hucht, K. A. Van Der, Miller, N. A., Cassinelli, Joe P.

We present the analysis of XMM-Newton observations of ζ Orionis. The analysis is based on fitting to the total spectrum as well as diagnostics of individual line.

XMM-Newton Studies of the Wolf-Rayet Colliding-Wind Binaries WR 25 (WN6h+O4f) and WR 11 (WC8+O7.5III) (2007)

Van Der Hucht, K A, Raassen, A J J, Mewe, R, Antokhin, I I, Rauw, Grégor, Vreux, J-M, ...

We report the analysis of high- and medium-resolution X-ray spectra of the Wolf-Rayet (WR) objects WR25 (HD93162, WN6h+O4f) and WR11 (gamma[SUP]2[/SUP] Velorum, WC8+O7.5III, P =78.53 d), obtained...

The X-ray spectra of the flaring and quiescent states of YZ CMi observed by XMM-Newton (2007)

Raassen, A.J.J., Mitra-Kraev, U., Güdel, M.

We analyse the X-ray spectrum of the active late-type star YZ CMi (M4.5V); for quiescent as well as active stages, we derive emission measure (EM) distributions, elemental abundances, and electron...

X-ray variability of Capella (2007)

Raassen, A.J.J., Kaastra, J.S.

We discuss 12 individual observations of stable calibration source Capella over the last five years. The light curves and spectra, derived from LETGS on board CHANDRA are investigated. The spectra...

X-ray variability of Capella (2007)

Raassen, A.J.J., Kaastra, J.S.

We discuss 12 individual observations of stable calibration source Capella over the last five years. The light curves and spectra, derived from LETGS on board CHANDRA are investigated. The spectra...

Relationship between X-ray and ultraviolet emission of flares from dMe stars observed XMM-Newton (2005)

Mitra-Kraev, U., Harra, L.K., Gudel, M., Audard, M., Branduardi-Raymont, G., Kay, H.R.M., ...

XMM-Newton observations of beta Centauri (B1 III): The temperature structure in the hot plasma and the photosphere-wind connection (2005)

Raassen, A.J.J., Cassinelli, J.P., Miller, N.A., Mewe, R., Tepedelenlioglu, E.

We present XMM-Newton observations of the B giant beta Centauri (B1 III). The spectra are rich of spectral lines from a wide range of ionization stages which indicate temperatures in the range...

Relationship between X-ray and ultraviolet emission of flares from dMe stars observed by XMM-Newton (2004)

Mitra-Kraev, U., Harra, L. K., Guedel, M., Audard, M., Branduardi-Raymont, G., Kay, H. R. M., ...

We present simultaneous ultraviolet and X-ray observations of the dMe-type flaring stars AT Mic, AU Mic, EV Lac, UV Cet and YZ CMi obtained with the XMM-Newton observatory. During 40 hours of...

X-ray/UV campaign on the Mrk 279 outflow: density diagnostics in Active Galactic Nuclei using O V K-shell absorption lines (2004)

Kaastra, J. S., Raassen, A. J. J., Mewe, R., Arav, N., Behar, E., Gabell, J. R., ...

One of the main problems in modeling the ionised outflows in Active Galactic Nuclei is the unknown distance of the outflowing wind to the central source. Only if the density is known this distance...

Wind clumping and the wind-wind collision zone in the Wolf-Rayet binary gamma Velorum (2004)

Schild, H., Guedel, M., Mewe, R., Schmutz, W., Raassen, A. J. J, Audard, M., ...

We present XMM-Newton observations of gamma^2 Velorum (WR 11, WC8+O7.5III, P = 78.53 d), a nearby Wolf-Ray binary system, at its X-ray high and low states. At high state, emission from a hot...

XMM-Newton X-ray observations of gamma2 Velorum (WC8 + O7.5III) (2004)

Raassen, A.J.J., Mewe, R., Hucht, K.A. Van Der, Schmutz, W., Schild, H., Dumm, T., ...

X-ray/UV campaign on the Mrk 279 outflow: Density diagnostics in Active Galactic Nuclei using O V K-shell absorption lines (2004)

Kaastra, J.S., Raassen, A.J.J., Mewe, R., Arav, N., Behar, E., Costantini, E., ...

One of the main problems in modeling the ionised outflows in Active Galactic Nuclei is the unknown distance of the outflowing wind to the central source. Only if the density is known this distance...

Wind clumping and the wind-wind collision zone in the Wolf-Rayet binary gamma ? Velorum observations at high and low state. XMM-Newton observations at high and low state (2004)

Schild, H., Gudel, M., Mewe, R., Schmutz, W., Raassen, A.J.J., Audard, M., ...

We present XMM-Newton observations of gamma2 Velorum (WR 11, WC8+O7.5III, P = 78.53 d), a nearby Wolf-Rayet binary system, at its X-ray high and low states. At high state, emission from a hot...

The X-ray spectra of the flaring and quiescent states of AT Microscopii observed by XMM-Newton (2003)

Raassen, A. J. J., Mewe, R., Audard, M., Guedel, M.

The X-ray spectrum of the late-type M-dwarf binary AT Mic (dM4.5e+dM4.5e) is observed in the wavelength range 1 - 40 Angstrom by means of rgs and epic-mos on board XMM-Newton. During the exposure a...

AD Leonis: Flares observed by XMM-Newton and Chandra (2003)

Besselaar, E. J. M. Van Den, Raassen, A. J. J., Mewe, R., Van Der Meer, R. L. J., Guedel, M., Audard, M.

The M-dwarf AD Leonis has been observed with the Reflection Grating Spectrometers and the European Photon Imaging Camera aboard XMM-Newton and also with the Low Energy Transmission Grating...

Coronal X-Ray Spectroscopy of Solar Analogs (2003)

Telleschi, A., Guedel, M., Audard, M., Arzner, K., Mewe, R., Raassen, A.J.J., ...

Performance and results of the reflection grating spectrometers onboard XMM-Newton (2003)

Herder, J.W. Den, Brinkman, A.C., Kahn, S.M., Branduardi-Raymont, G., Audard, M., Behar, E., ...

AD Leonis, (dM3:l5V): Analysis of the x-ray spectrum (2003)

Besselaar, E.J.M. Van Den, Raassen, A.J.J., Mewe, R., Meer, R.L.J. Van Der, Gudel, M., Audard, M.

XMM-Newton high-resolution x-ray spectroscopy of the Wolf-Rayet object WR25 (WN6HA+04F) (2003)

Raassen, A.J.J., Hucht, K.A. Van Der, Mewe, R., Antokhin, I.I., Rauw, G., Vreux, J.M., ...

High-resolution XMM-Newton X-ray spectra of ? SCORPII (2003)

Mewe, R., Raassen, A.J.J., Cassinelli, J.P., Hucht, K.A. Van Der, Miller, N.A., Gudel, M.

The X-ray spectra of the flaring and quiescent states of AT Microscopii observed by XMM-Newton (2003)

Raassen, A.J.J., Mewe, R., Audard, M., Gudel, M.

AD Leonis: Flares observed by XMM-Newton and Chandra (2003)

Besselaar, E.J.M. Van Den, Raassen, A.J.J., Mewe, R., Meer, R.L.J. Van Der, Gudel, M., Audard, M.

XMM-Newton high-resolution X-ray spectroscopy of the Wolf-Rayet object WR 25 in the Carina OB1 association (2003)

Raassen, A.J.J., Hucht, K.A. Van Der, Mewe, R., Antokhin, I.I., Rauw, G., Vreux, J.M., ...

Chandra-LETGS X-ray observation of alpha Centauri: A nearby (G2V + K1V) binary system (2003)

Raassen, A.J.J., Ness, J.-U., Mewe, R., Meer, R.L.J. Van Der, Burwitz, V., Kaastra, J.S.

A study of coronal abundances in RS CVn binaries (2003)

Audard, M., Gudel, M., Sres, A., Raassen, A.J.J., Mewe, R.

High-resolution X-ray spectroscopy of tau Scorpii (B0.2V) with XMM-Newton (2003)

Mewe, R., Raassen, A.J.J., Cassinelli, J.P., Hucht, K.A. Van Der, Miller, N.A., Gudel, M.

New Results on X-Ray Models and Atomic Data (2003)

Kaastra, J.S., Mewe, R., Raassen, A.J.J.

Chandra-LETGS X-ray observation of α Centauri : A nearby (G2V + K1V) binary system (2003)

Raassen, A. J. J., Ness, J.-U., Mewe, R., Van Der Meer, R. L. J., Burwitz, V., Kaastra, J. S.

Coronal density diagnostics with Helium-like triplets: CHANDRA--LETGS observations of Algol, Capella, Procyon, Eps Eri, Alpha Cen A&B, UX Ari, AD Leo, YY Gem, and HR1099 (2002)

Ness, J. -U., Schmitt, J. H. M. M., Burwitz, V., Mewe, R., Raassen, A. J. J., Van Der Meer, R. L. J., ...

We present an analysis of ten cool stars (Algol, Capella, Procyon, Eps Eri, Alpha Cen A&B, UX Ari, AD Leo, YY Gem, and HR1099) observed with the Low Energy Transmission Grating Spectrometer (LETGS)...

High-resolution X-ray spectroscopy of Procyon by Chandra and XMM-Newton (2002)

Raassen, A. J. J., Mewe, R., Audard, M., Guedel, M., Behar, E., Kaastra, J. S., ...

We report the analysis of the high-resolution soft X-ray spectrum of the nearby F-type star Procyon in the wavelength range from 5 to 175 Angstrom obtained with the Low Energy Transmission Grating...

X-ray powerful diagnostics for highly-ionized plasmas: He-like ions (2002)

Porquet, D., Mewe, R., Kaastra, J. S., Dubau, J., Raassen, A. J. J.

The calculations of the ratios of the Helium-like ion X-ray lines from C V to Si XIII are revisited in order to apply the results to density, temperature and ionization process diagnostics of data...

X-ray spectroscopy of NGC 5548 (2002)

Kaastra, J. S., Steenbrugge, K. C., Raassen, A. J. J., Van Der Meer, R. L. J., Brinkman, A. C., Liedahl, D. A., ...

We analyze the high-resolution X-ray spectrum of the Seyfert 1 galaxy NGC 5548, for the full 0.1-10 keV band, using improved calibration results of the Chandra-LETGS instrument. The warm absorber...

Emission measure modeling and abundance determination of Procyon by means of a variety of instruments on board Chandra and XMM-Newton (2002)

Raassen, A.J.J., Audard, M., Mewe, R., Gudel, M., Meer, R.L.J. Van Der, Behar, E.

Influence of radiation fields on the density diagnostics Chandra-Letgs observations of Algol and Procyon (2002)

Ness, J.-U., Mewe, R., Schmitt, J.H.M.M., Raassen, A.J.J.

XMM-Newton probes the solar past: Coronal abundances of solar analogs at different ages (2002)

Gudel, M., Audard, M., Sres, A., Wehrli, R., Behar, E., Mewe, R., ...

Coronal density diagnostics with Heilium-like triplets: Chandra-Letgs observations of Algol, Capella, Procyon, Epsilon Eri, Alpha Cen A&B, and UX Ari (2002)

Ness, J.-U., Mewe, R., Schmitt, J.H.M.M., Raassen, A.J.J., Meer, R.L.J. Van Der, Burwitz, V., ...

A Study of the Coronal Plasma in RS CVn binary systems: HR1099 and co. (2002)

Audard, M., Gudel, M., Sres, A., Mewe, R., Raassen, A.J.J., Behar, E., ...

The FERRUM Project: New f-value Data for Fe II and Astrophysical Applications (2002)

Johansson, S., Derkatch, A., Donnelly, M.P., Hartman, H., Hibbert, A., Karlsson, H., ...

The X-ray Spectrum of Tau Sco (2002)

Raassen, A.J.J.

Coronal density diagnostics with Helium-like triplets: CHANDRA-LETGS observations of Algol, Capella, Procyon, epsilon Eri, alpha Cen A&B, UX Ari, AD Leo, YY Gem, and HR 1099 (2002)

Ness, J.-U., Schmitt, J.H.M.M., Burwitz, V., Mewe, R., Raassen, A.J.J., Meer, R.L.J. Van Der, ...

X-ray spectroscopy of NGC 5548 (2002)

Kaastra, J.S., Steenbrugge, K.C., Raassen, A.J.J., Meer, R.L.J. Van Der, Brinkman, A.C., Liedahl, D.A., ...

High-resolution X-ray spectroscopy of Procyon by Chandra and XMM-Newton (2002)

Raassen, A.J.J., Mewe, R., Audard, M., Gudel, M., Behar, E., Kaastra, J.S., ...

Coronal density diagnostics with Helium-like triplets: CHANDRA- LETGS observations of Algol, Capella, Procyon, ε Eri, α Cen A & B, UX Ari, AD Leo, YY Gem, and HR 1099 (2002)

Ness, J.-U., Schmitt, J .H. M. M., Burwitz, V., Mewe, R., Raassen, A. J. J., Van Der Merr, R. L. J., ...

We present an analysis of ten cool stars (Algol, Capella, Procyon, epsilon Eri, alpha Cen A&B, UX Ari, AD Leo, YY Gem, and HR1099) observed with the Low Energy Transmission Grating Spectrometer...

Coronal density diagnostics with Helium-like triplets: Chandra-LETG observations of Algol, Capella, Procyon, ε Eri, α Cen A&B, and UX Ari (2002)

Ness, J.-U., Mewe, R., Schmitt, J. H. M. M., Raassen, A. J. J., Van Der Meer, R. L. J., Burwitz, V., ...

A Study of the Coronal Plasma in RS CVn binary systems: HR 1099 and co (2001)

Audard, M., Guedel, M., Sres, A., Mewe, R., Raassen, A. J. J., Behar, E., ...

XMM-Newton has been performing comprehensive studies of X-ray luminous RS CVn binary systems in its calibration and guaranteed time programs. We present results from ongoing investigations in the...

XMM-Newton Probes the Solar Past: Coronal Abundances of Solar Analogs at Different Ages (2001)

Guedel, M., Audard, M., Sres, A., Wehrli, R., Behar, E., Mewe, R., ...

We present an X-ray spectral analysis of four solar analogs with different ages and magnetic activity levels. We find largely different coronal compositions. The most active stars tend to show an...

A Systematic Spectroscopic X-Ray Study of Stellar Coronae with XMM-Newton: Early Results (2001)

Guedel, M., Audard, M., Smith, K. W., Sres, A., Escoda, C., Wehrli, R., ...

We have been conducting a comprehensive survey of stellar coronae with the XMM-Newton Reflection Grating Spectrometers during the commissioning, calibration, verification, and guaranteed time phases...

A Study of the Coronal Plasma in RS CVn binary systems (2001)

Audard, M., Guedel, M., Sres, A., Mewe, R., Raassen, A. J. J., Behar, E., ...

XMM-Newton has been performing comprehensive studies of X-ray bright RS CVn binaries in its Calibration and Guaranteed Time programs. We present results from ongoing investigations in the context of...

Line ratios for Helium-like ions: Applications to collision-dominated plasmas (2001)

Porquet, D., Mewe, R., Dubau, J., Raassen, A. J. J., Kaastra, J. S.

The line ratios R and G of the three main lines of He-like ions (triplet: resonance, intercombination, forbidden lines) are calculated for CV, NVI, OVII, NeIX, MgXI, and SiXIII. These ratios can be...

Emission measure modeling and abundance determination of Alpha Centauri and Procyon (2001)

Raassen, A.J.J., Mewe, R., Ness, J.-U.

Stellar Coronae with XMM-Newton RGS II. X-ray Variability (2001)

Audard, M., Gudel, M., Boggende, A.J. Den, Brinkman, A.C., Herder, J.W. Den, Kaastra, J.S., ...

Stellar Coronae with XMM-Newton RGS I. Coronal Structure (2001)

Gudel, M., Audard, M., Boggende, A.J. Den, Brinkman, A.C., Herder, J.W. Den, Kaastra, J.S., ...

Helium-like ions as powerful X-ray plasma diagnostics (2001)

Porquet, D., Mewe, R., Raassen, A.J.J., Dubau, J.

Line ratios for helium-like ions: Applications to collision-dominated plasmas (2001)

Porquet, D., Mewe, R., Dubau, J., Raassen, A.J.J., Kaastra, J.S.

CHANDRA-LETGS X-ray observations of Capella. Temperature, density and abundance diagnostics (2001)

Mewe, R., Raassen, A.J.J., Drake, J.J., Kaastra, J.S.

Helium-like triplet density diagnostics. Applications to CHANDRA-LETGS X-ray observations of Capella and (2001)

Ness, J.-U., Mewe, R., Schmitt, J.H.M.M., Raassen, A.J.J.

The XMM-Newton view of stellar coronae: High-resolution X-ray spectroscopy of Capella (2001)

Audard, M., Behar, E., Gudel, M., Raassen, A.J.J.

Helium-like ions as powerful X-ray plasma diagnostics (2000)

Porquet, D., Mewe, R., Raassen, A. J. J, Kaastra, J. S., Dubau, J.

We revisited the calculations of the ratios of the Helium-like ion ``triplet'' (resonance, intercombination, and forbidden lines) for Z=6 to 14 (C V, N VI, O VII, Ne IX, Mg XI, Si XIII) in order to...

Helium-like triplet density diagnostics: Applications to CHANDRA--LETGS X-ray observations of Capella and Procyon (2000)

Ness, J. U., Mewe, R., Schmitt, J. H. M. M., Raassen, A. J. J., Porquet, D., Kaastra, J. S., ...

Electron density diagnostics based on the triplets of Helium-like CV, NVI, and OVII are applied to the X-ray spectra of Capella and Procyon measured with the Low Energy Transmission Grating...

Stellar Coronae with \textit{XMM-Newton} RGS. I. Coronal Structure (2000)

Guedel, M., Audard, M., Boggende, A. J. Den, Brinkman, A. C., Herder, J. W. Den, Kaastra, J. S., ...

First results from high-resolution coronal spectroscopy with the {\it XMM-Newton} Reflection Grating Spectrometers (RGS) are reviewed. Five stellar systems (HR 1099, Capella, Procyon, YY Gem, AB Dor)...

Stellar Coronae with \textit{XMM-Newton} RGS. II. X-ray Variability (2000)

Audard, M., Guedel, M., Boggende, A. J. Den, Brinkman, A. C., Herder, J. W. Den, Kaastra, J. S., ...

First results from high-resolution coronal spectroscopy of flares with the Reflection Grating Spectrometers on board the \textit{XMM-Newton} satellite are reviewed. Rotational modulation in the X-ray...

First Light Measurements of Capella with the Low Energy Transmission Grating Spectrometer aboard the Chandra X-ray Observatory (2000)

Brinkman, A. C., Gunsing, C. J. T., Kaastra, J. S., Van Der Meer, R. L. J., Mewe, R., Paerels, F., ...

We present the first X-ray spectrum obtained by the Low Energy Transmission Grating Spectrometer (LETGS) aboard the Chandra X-ray Observatory. The spectrum is of Capella and covers a wavelength range...

The FERRUM project: new experimental and theoretical f-values for the 4p-4d transitions in Fe II applied to HST spectra on chi Lupi (2000)

Nilsson, H., Sikstrom, C.M., Li, Z.S., Lundberg, H., Raassen, A.J.J., Johansson, S., ...

First light measurements of Capella with the low-energy transmission grating spectrometer aboard the Chandra X-ray observatory (2000)

Brinkman, A.C., Gunsing, C.J.T., Kaastra, J.S., Meer, R.L.J. Van Der, Mewe, R., Paerels, F., ...

The FERRUM project: experimental lifetimes of highly excited Fe II 3d64p levels and transition probabilities (1999)

Sikstrom, C.M., Schultz-Johanning, M., Kock, M., Li, Z.S., Nilsson, H., Johansson, S., ...

Calculations of oscillator strengths for singly ionized iron group elements by means of the orthogonal operator approach (1998)

Raassen, A.J.J., Uylings, P.H.M.

The platinum group ion project (1998)

Azarov, V.I., Churilov, S., Kidiyarova, R., Ryabtsev, A.N., Raassen, A.J.J., Uylings, P.H.M., ...

On the determination of the solar iron abundance using Fe II lines. (1998)

Raassen, A.J.J., Uylings, P.H.M.