Frits Paerels at CAL.

Columbia University Astronomy and Astrophysics

Frits Paerels

e-mail: frits@astro.columbia.edu

Telephone: (212) 854-0181

Gamma Ray Burst Chandra TOO Form

Research Interests:
- X-ray astronomy (active galactic nuclei, clusters of galaxies, X-ray binaries, neutron stars)
- and more specifically: X-ray spectroscopy
- intergalactic medium; cosmology
- fundamental properties of neutron stars
- instrumentation

Student Projects are on this page !

Classes
Fall 2003:
- Astronomy C2001 "Introduction to Astrophysics, I"
Spring 2003:
-Astronomy/Physics G6011 "High Energy Astrophysics"
Fall 2002:
- Astronomy C2001 "Introduction to Astrophysics, I"
Spring 2002:
-Astronomy   C1420 "Galaxies and Cosmology"
Fall 2001:
-Astronomy C1836"Stars and Atoms"
Spring 2001:
-Astronomy G6011 "High Energy Astrophysics"

For the last several years, the XMM/RGS group
at Columbia has been working on the design, construction, and calibration of the Reflection Grating Spectrometer (RGS) for ESA's XMM-Newton X-ray observatory. The image to the right shows one of the two Reflection Grating Arrays we built at Columbia. Reflection Grating Array RGA2

This instrument is now providing an abundance
of dramatic high resolution spectroscopic data, which is changing our understanding of practically all types
of cosmic X-ray source. I'm involved in the interpretation of these novel spectroscopic data, as well as in the analysis of spectroscopy obtained with the diffraction grating spectrometers on Chandra.

Examples of data obtained with XMM are the high resolution RGS spectrum of the Seyfert 2 galaxy NGC 1068, to the left, which shows that the discrete emission in the nuclear region is dominated by emission from X-ray photoionized gas (image courtesy Ali Kinkhabwala).
To the right is an X-ray image of the cluster of galaxies Abell 1835. Prior to observations with XMM, the very bright central region was thought to harbor large amounts of radiatively cooling gas. The spectrum of the central region obtained with the RGS, however, shows that there are no detectable amounts of gas below a temperature of ~2 keV. The same behavior is seen in other cooling-flow clusters.
Here is the paper by John Peterson et al. that describes this result.

The first high resolution spectrum of an X-ray photoionization dominated source was obtained with the High Energy Transmission Grating Spectrometer (HETGS) on Chandra. Jean Cottam, Masao Sako, Duane Liedahl, and I analyzed this unusual spectrum, and identified an array of novel spectroscopic diagnostics of recombination-driven discrete X-ray emission.
The images to the right show the central portion of the spectral image on ACIS/S3 (zero order, and light dispersed by the MEG and HEG), and the resulting spectra.

I want to try and see if we can find dust in the intergalactic medium at high redshift.
Detection of such dust would provide us
with an independent way to trace the
cosmic star formation rate.
If abundant in sufficiently large amounts, it may
even have implications for the interpretation of the Hubble Diagram of type Ia Supernovae
and the evidence that the expansion of
the Universe is accelerating.
The image to the left shows a simulated X-ray
scattering halo around a distant quasar, produced by intergalactic dust, as it would be observed with Chandra/ACIS. The field is 8x8 arcmin, the pixel
size 1x1 arcsec.

with Celia on Devil's Island, French Guyana (photo Carl Dobson)

Finally, I think we should attempt to detect the X-ray emission from the local intergalactic medium, where half the baryons at the current epoch should be, and work on instrumentation to carry out
such an experiment.
The image to the right is the simulation for the distribution of the warm IGM by
Cen & Ostriker (Ap.J., 514, L1 [1999]).
background

2001-present
1999-2001

Associate Professor
Adjunct Associate Professor,
Department of Astronomy,
Columbia University

1999-present Director, Columbia Astrophysics Laboratory

1998-1999                Senior Scientist, SRON Space
                                   Research Laboratory,
                                   Utrecht, the Netherlands
1995-present         Research Scientist,
                              Columbia Astrophysics Lab
1990-1995           Assistant Research Physicist
                                   Univ. of California, Berkeley
1988-1990            Postdoctoral Fellow, Univ. of
                                    California, Berkeley, and
                                    IGPP, LLNL
1988                       PhD, University of Utrecht,
                                    the Netherlands

Some Recent Publications

'X-ray Imaging Spectroscopy of Abell 1835', J. R. Peterson, F. B. S. Paerels, J. S. Kaastra, M. Arnaud, T. H. Reiprich, A. C. Fabian, R. F. Mushotzky, J. G. Jernigan, I. Sakelliou, 2001, A&A, 365, L104.
'XMM-Newton Observations of the cluster of Galaxies Sersic 159-03', J. S. Kaastra, C. Ferrigno, T. Tamura, F. B. S. Paerels, J. R. Peterson, J. P. D. Mittaz, 2001, A&A, 365, L99.
'X-ray spectroscopy of the cluster of galaxies Abell 1795 with XMM-Newton', T. Tamura, J. S. Kaastra, J. R. Peterson, F. Paerels, J. P. D. Mittaz, S. P. Trudolyubov, G. Stewart, A. C. Fabian, R. F. Mushotzky, D. H. Lumb, Y. Ikebe, 2001, A&A, 365, L87.
'First XMM-Newton observations of an isolated neutron star: RXJ0720.4-3125', Frits Paerels, Kaya Mori, Christian Motch, Frank Haberl, Vyacheslav E. Zavlin, Silvia Zane, Gavin Ramsay, Mark Cropper, and Bert Brinkman, 2001, A&A,365, L298.
'The Reflection Grating Spectrometer on XMM_Newton' J. W. den Herder, A. C. Brinkman, S. M. Kahn, G. Branduardi-Raymont, K. Thomsen, H. Aarts, M. Audard, J. V. Bixler, A. den Boggende, J. Cottam, T. Decker, L. Dubbeldam, C. Erd, H. Goulooze, M. Guedel, P. Guttridge, C. J. Hailey, K. Al Janabi, J. S. Kaastra, P. A. J. de Korte, B. J. van Leeuwen, C. Mauche, A. McCalden, R. Mewe, A. Naber, F. Paerels, J. R. Peterson, A. P.Rasmussen, K. Rees, I. Sakelliou, M. Sako, J. Spodek, M. Stern, T. Tamura, J. Tandy, C. de Vries, S. Welch, A. Zehnder, A&A, 365, L7.
'X-ray Spectral Diagnostics of Gamma-Ray Burst Environments', Frits Paerels, Erik Kuulkers, John Heise, and Duane A. Liedahl, 2001, Ap. J. (Letters), 535, L25.
'High Resolution Spectroscopy of the X-ray Photoionized Wind in Cygnus X-3 with the Chandra High Energy Transmission Grating Spectrometer', Frits Paerels, Jean Cottam, Masao Sako, Duane A. Liedahl, A. C. Brinkman, R. L. J. van der Meer, J. S. Kaastra, and P. Predehl, 2000, Ap. J. (Letters), 533, L135.
'High resolution Spectroscopy with XMM', Paerels', F., Brinkman, A. C., den Herder, J.-W., de Vries, C., den Boggende, A. J. F., Mewe, R., Kaastra, J., Kahn, S. M., Rasmussen, A., Decker, T., Stern, M., Cottam, J., Spodek, J., Branduardi-Raymont, G., Guedel, M., Liedahl, D., Erd, C., Proceedings First XMM Workshop, October 31-November 2, 1998, Estec, the Netherlands.
'Future X-ray Spectroscopy Missions', in 'X-ray Spectroscopy', Proceedings of the European Astrophysics Doctoral Network Tenth Summer School, J. van Paradijs (Ed.) (Springer: 1998).
'Pressure Broadening of Absorption Lines in Neutron Star Atmosphere and Prospects for Measuring Neutron Star Masses and Radii', Paerels, F., 1997, Ap. J. (Letters), 476, L47.
'Photoionization Driven X-ray Line Emission in Cygnus X-3', 1996, Liedahl, D. A., and Paerels, F., Ap. J. (Letters), 468, 33L.


1996 November 16	www@astro.columbia.edu

Frits Paerels

e-mail: frits@astro.columbia.edu Telephone: (212) 854-0181

e-mail: frits@astro.columbia.edu

Telephone: (212) 854-0181