Dr. Tahir Yaqoob - Curriculum Vitae

Personal Data

Date of Birth: 1965 May 4

Nationality: British

Contact information

Present Positions

Research Scientist in Astrophysics & JHU/GSFC/ coordinater of Cooperative research in High Energy Astrophysics.

Adjunct Faculty, George Washington University

Previous Positions

1999-2000, Adjunct Faculty, Prince George's Community College
1992-2000, Post-doctoral Researcher->Associate Research Scientist (NASA/ GSFC/ USRA/UMBC).
1991-1992, Royal Society Fellowship, Institute of Astronomy, Cambridge, UK
1990-1991, Royal Society/JSPS Fellowship, Institute of Space & Astronautical Science, Japan

Research Area

X-ray Astronomy; Active Galactic Nuclei, Accreting Black Hole systems; High-Energy Astrophysical Processes

see full CV
and publications.

Education

1983-1986, BA (Hons), Physics, University of Oxford, UK
1986-1990, PhD, "X-ray Spectral Variability As A Probe Of Active Galactic Nuclei", University of Leicester, UK

Professional Society Memberships

American Astronomical Society

Awards & Honors

2000 Long Term Space Astrophysics (LTSA) grant Award.
1996 May 09 NASA/GSFC 'Group Achievement Award' for "ASCA Missions Operations Team"
1993 Oct 07 NASA/GSFC 'Special Act Group Award' for "ASCA Team"

Community Service

  • Peer Reviews for ASCA, Chandra.

  • Regular Referee for Papers in Professional Journals

    Other Experience

  • Chair, organizing committee of international workshop on X-ray Emission from Accretion onto Black Holes, held at Johns Hopkins University, June 2001.
  • Numerical modeling and data analysis software design; languages: IDL, Fortran, C++
  • Software documentation and Data Analysis Systems documentation. Technical documentation for proposal preparation and instrument calibration.

    Citations

    Cumulative number of citations (to March 21, 2000) since 1990, including non-first author papers, is 1140.
    Including first-author papers only, it is 429 (source: Institute for Scientific Information).

    Invited Talks

  • Structure and Kinematics in the Central Engine of AGN: New Results from High Resolution and High Throughput Spectroscopy.
    Workshop: Light From Black Holes, Kathmandu, Nepal. 4 October, 2002.

  • What Kind of Obscured AGN Make the X-ray Background?
    Workshop: Large Scale Structure in the X-ray Universe, Santorini, Greece. 20-22 September 1999.

  • X-ray Observations Of NGC 4151.
    Workshop: X-rays and Gamma-rays from Accreting Black Holes, Koninki, Poland. 13 June 1996.

  • Physical Constraints Imposed By Recent Iron K Line Measurements In AGN
    Symposium: X-ray Imaging & Spectroscopy Of Cosmic Hot Plasmas, Waseda University, Tokyo, Japan. 12 March 1996.

  • ASCA Observations of High Redshift Quasars.
    Symposium: Washington Area Astronomer's meeting. March 16, 1994.

  • ASCA Observations of Quasars in the PV Phase.
    Symposium: New Horizon of X-ray Astronomy, Tokyo, Japan. March 11, 1994.

    Other Recent Talks

  • High Resolution Spectroscopy of AGN using Astro-E2 XRS in the Light of Chandra & XMM Results.
    Astro-E2 Science Working Group Meeting, ISAS, Japan. 12 March 2003.

  • New Results from Chandra Grating Observations of AGN.
    Workshop: High resolution X-ray spectroscopy with XMM-Newton and Chandra, MSSL, UK. 25 October 2002.

  • New Chandra Results on Warm Absorbers and Iron K Lines in AGN.
    Symposium: Active Galactic Nuclei: From Central Engine to Host Galaxy, Paris, France. 23 July 2002.

    Teaching Experience (since 1987)

  • HND (UK) materials science, physics and chemsitry.
  • Physics and Astronmy Labs & Problems Classes (Leicester U.).
  • Undergraduate level astrophysics lectures (Cambridge U., GWU).
  • Graduate level course, "The Universe at High Energies" (JHU).
  • Co-adviser of three Graduate PhD students in astrophysics.
  • Graduate level Mathematical Physics (PDEs, ODEs, IVP, BVP etc.).
  • Astronomy 101 course.
  • High school algebra I and II, pre-calculus, calculus, physics, chemsitry.
  • Oxford and Cambridge entrance exams.

    Publications

    [REFEREED JOURNALS]

    Refereed Publications (Tahir Yaqoob)

    81: Iron K Features in the Quasar E 1821+643: Evidence for Gravitationally Redshifted Absorption
    Tahir Yaqoob & Peter Serlemitsos 2004, ApJ, submitted
    1: The X-ray Spectrum of QSO 1821+643
    Warwick, R. S., Barstow, M. A. & Yaqoob, T.,
    1989, MNRAS, 238, 917
    2: A GINGA Observation of NGC 4151
    Warwick, R. S., Yaqoob, T., Pounds, K. A., Matsuoka, M. & Yamauchi, M.,
    1989, PASJ, 41, 721
    3: Variable X-ray Absorption in NGC 4151
    Yaqoob, T., Warwick, R. S. & Pounds, K. A.,
    1989, MNRAS, 236, 153
    4: A Search for Reflection Features in the X-ray Spectrum of NGC 4151
    Maisack, M. & Yaqoob, T.,
    1991, A&A, 249, 25
    5: The X-ray Spectral Variability of NGC 4151
    Yaqoob, T. & Warwick, R. S.,
    1991, MNRAS, 248, 773
    6: Nonthermal Pair Models of the Spectral Index Variability in NGC 4151
    Yaqoob, T.,
    1992, MNRAS, 258, 198
    7: The X-ray Properties of Active Galaxies with High Intrinsic Absorption
    Warwick, R. S., Sembay, S., Yaqoob, T., Makishima, K., Ohashi, T. & Tashiro, M.,
    1993, MNRAS, 265, 412
    8: Is X1957+11 a Black Hole Candidate?
    Yaqoob, T., Ebisawa, K. & Mitsuda, K.,
    1993, MNRAS, 264, 411
    9: The Fe K Line As A Probe Of Beamed X-ray Emission In AGN
    Yaqoob, T., McKernan, B., Done, C., Serlemitsos, P. J. & Weaver, K. A.,
    1993, ApJ, 416, L5
    10: A BBXRT Observation of the High Luminosity Quasar H1821+643
    Yaqoob, T., Serlemitsos, P. J., Mushotzky, R. F., Weaver, K. A., & Marshall, F. E., Petre R.,
    1993, ApJ, 418, 638
    11: Further Probing of the X-ray Source in NGC 4151: New Constraints on the Nuclear Geometry
    Yaqoob, T., Warwick, R. S., Makino, F., Otani, C., Sokoloski, J. L., Bond, I. A. & Yamauchi, M.,
    1993, MNRAS, 262, 435
    12: Low State Properties of the Low Mass X-ray Binary X1608-522 Observed with Ginga
    Yoshida, K., Mitsuda, K., Ebisawa, K., Ueda, Y., Fujimoto, R., Yaqoob, T. & Done, C.,
    1993, PASJ, 45, 605
    13: ASCA Observation of the Warm Absorber in MCG -6-30-15; the Discovery of a Change in Column Density
    Fabian, A. C., Inoue, H., Kunieda, H., Matsuoka, M., Mihara, T., Miyamoto, S., Otani, C., Ricker, G., Tanaka, Y., Yamauchi, M. & Yaqoob, T.,
    1994, PASJ, 46, L59
    14: An ASCA Observation of the Seyfert 2 Galaxy Markarian 3
    Iwasawa, K., Yaqoob, T., Awaki, H. & Ogasaka, Y.,
    1994, PASJ, 46, L167
    15: Discovery of an Obscured Low Luminosity Active Nucleus in the Spiral Galaxy NGC 4258
    Makishima, K., Serlemitsos, P. J., Tashiro, M., Fujimoto, R., Ishisaki, Y., Kii, T., Lowenstein, M., Mushotzky, R., Sonobe, T. & Yaqoob, T.,
    1994, PASJ, 46, L77
    16: Rapid X-ray Spectral Variability in NGC 3227
    Ptak, A., Yaqoob, T., Serlemitsos, P. J., Mushotzky, R. F. & Otani, C.,
    1994, ApJ, 436, L31
    17: The Complex X-ray Spectra of Two High Redshift Quasars Observed with ASCA
    Serlemitsos, P. J., Yaqoob, T., Ricker, G., Woo, J., Kunieda, H., Terashima, Y., & Iwasawa, K.,
    1994, PASJ, 46, L43
    18: New X-ray Spectral Observations of NGC 4151 with ASCA
    Weaver, K. A., Holt, S. S., Yaqoob, T., Mushotzky, R. F., Matsuoka, M. & Yamauchi, M.,
    1994, ApJ, L27
    19: An ASCA Observation of One Orbital Cycle of AR Lac
    White, N., Arnaud, K., Day, C. S. R., Ebisawa, K., Gotthelf, E. V., Mukai, K., Soong, Y., Yaqoob, T. & Antunes, A.,
    1994, PASJ, 46, L97
    20: X-ray Spectrum and Variability of the Quasar PG 1211+143
    Yaqoob, T., Serlemitsos, P. J., Mushotzky, R. F., Madejski, G., Turner, T. J. & Kunieda, H.,
    1994, PASJ, 46, L173
    21: The X-ray Emission of 3C 273 Observed with ASCA
    Yaqoob, T., Serlemitsos, P. J., Mushotzky, R. F., Ricker, G., Woo, J., Weaver, K., Kii, T., Mitsuda, K., Kotani, T., Hayashida, K., Murakami, S. & Tashiro, M.,
    1994, PASJ, 46, L49
    22: The Hard X-ray Emission of NGC 3628 and the Contribution of Low-Luminosity Spiral Galaxies to the Cosmic X-ray Background
    Yaqoob, T., Serlemitsos, P. J., Ptak, A., Mushotzky, R. F., Kunieda, H., & Terashima, Y.,
    1995, ApJ, 455, 508
    23: An ASCA X-ray Spectrum of a Prototype Bare Seyfert 1 Nucleus in MCG-2-58-22
    Weaver, K. A., Nousek, J., Yaqoob, T., Hayashida, K., & Murakami, S.,
    1995, ApJ, 451, 147
    24: X-ray Reprocessing By a Molecular Torus in the Seyfert 1.9 Galaxy NGC 2992
    Weaver, K. A., Nousek., J., Yaqoob, T., Mushotzky, R. F., Makino, F., & Otani, C.,
    1995, ApJ, 458, 160
    25: The Nature of the Low-Luminosity AGN in NGC 3147
    Ptak., A., Yaqoob, T., Serlemitsos, P. J., Kunieda, H., & Terashima, Y.,
    1996, ApJ, 459, 542
    26: The Iron K-alpha Line Profile in NGC 4151
    Yaqoob, T., Edelson, R., Weaver, K. A., Warwick, R. S., Mushotzky, R. F., Serlemitsos, P. J., & Holt, S. S.,
    1995, ApJ, 453, L81
    27: X-ray Transmission in Cold Matter: Nonrelativistic Corrections For Compton Scattering
    Yaqoob, T.,
    1997, ApJ, 479, 184
    28: The X-ray Variability of MKN 766
    Leighly, K., Mushotzky, R. F., Yaqoob T., Kunieda, H., & Edelson, R.,
    1996, ApJ, 469, 147
    29: Reprocessing Models and the ASCA Spectrum of MKN 290
    Turner, T. J., George, I. M., Kallman, T., Yaqoob, T., & Zycki, P. T.,
    1996, ApJ, 472, 571
    30: Multiwaveband Observations of Short Time-Scale Variability in NGC 4151. I. Ultraviolet Observations
    Crenshaw, D. M., etal.
    1996 (87 authors), ApJ, 470, 322
    31: Multiwaveband Observations of Short Time-Scale Variability in NGC 4151. III. X-ray and Gamma-ray Observations
    Warwick, R. S., Smith, D. A., Yaqoob, T., Edelson, R., Johnson, W. N., Reichert, G. A., Clavel, J., Magdiziarz, P., Peterson, B. M., & Zdziarski, A. A.,
    1996, ApJ, 470, 349
    32: Multiwaveband Observations of Short Time-Scale Variability in NGC 4151. IV. Analysis of Multiwavelength Continuum Variability
    Edelson, R. etal.
    1996 (93 authors), ApJ, 470, 364
    33: ASCA Observations of Seyfert 1 Galaxies. I. Data Analysis, Imaging and Timing
    Nandra, K., George, I. M., Mushotzky, R. F., Turner, T. J., & Yaqoob, T.,
    1997, ApJ, 476, 70
    34: ASCA Observations of Seyfert 1 Galaxies. II. Relativistic Iron Kalpha Emission
    Nandra, K., George, I. M., Mushotzky, R. F., Turner, T. J., & Yaqoob, T.,
    1997, ApJ, 477, 602
    35: Iron K-alpha Evidence for Two X-Ray Reprocessors in MCG -5-23-16
    Weaver, K. A., Yaqoob, T., Mushotzky, R. F., Nousek, J., Hayashi, I., & Koyama, K.,
    1997, ApJ, 474, 675
    36: Discovery Of Rapid Variability Of The Iron K Line Profile In The Seyfert Galaxy NGC 7314
    Yaqoob, T., Serlemitsos, P. J., Turner, T. J., George, I. M., & Nandra, K.,
    1996, ApJL, 470, L27
    37: The Complex X-ray Spectra of M82 and NGC 253: Implications for the AGN-Starburst Connection
    Ptak, A., Serlemitsos, P. J., Yaqoob, T., & Tsuru, T.,
    1997, AJ, 113, 1286
    38: Variability of the Iron K Emission Line in the Seyfert Galaxy NGC 3516
    Nandra, K., Mushotzky, R. F., Yaqoob, T. George, I. M., & Turner, T. J.,
    1997, MNRAS, 284, L7
    39: On the dependence of the iron-K line profiles with luminosity in Active Galactic Nuclei
    Nandra, K., George, I. M., Mushotzky, R. F., Turner, T. J., & Yaqoob, T.,
    1997, ApJ, 488, L91
    40: A Simple New Method for Analyzing Gapped Time Series: Search for a High-frequency Cutoff in the X-Ray Power Spectrum of the Seyfert Galaxy MCG -6-30-15
    Yaqoob, T., McKernan, B., Ptak, A., Nandra, K., & Serlemitsos, P. J.,
    1997, ApJ, 490, L25
    41: ASCA Observations of Seyfert 1 Galaxies. III. The Evidence for Absorption and Emission Due to Photoionized Gas
    George, I. M., Turner, T. J., Netzer, H., Nandra, K., Mushotzky, R. F., & Yaqoob, T.,
    1998, ApJS, 114, 73
    42: Parameter Estimation in X-Ray Astronomy Revisited
    Yaqoob, T.,
    1998, ApJ, 500, 893
    43: Occultation Mapping of the Central Engine in the Active Galaxy MCG -6-30-15
    Mckernan, B., & Yaqoob, T.,
    1998, ApJ, 501, L29
    44: On the Evidence for Extreme Gravity Effects in MCG -6-30-15
    Weaver, K., & Yaqoob, T.,
    1998, ApJ, 502, L139
    45: X-Ray Variability as a Probe of Advection-dominated Accretion in Low-Luminosity Active Galactic Nuclei
    Ptak, A., Yaqoob, T., Muskotzky, R. F., Serlemitsos, P. J., & Griffiths, R. E.,
    1998, ApJ, 501, L37
    46: The X-ray Spectral Variability of the Seyfert Galaxy NGC 3227,
    George, I. M., Mushotzky, R. F., Turner, T. J., Yaqoob, T., Ptak, A., & Nandra, K.,
    1998, ApJ, astro-ph/9806392
    47: A Peculiar Emission Line Feature in the X-ray Spectrum of PKS 0637-752
    Yaqoob, T., George, I. M., Turner, T. J., Nandra, K., Ptak, A., & Serlemitsos, P. J.,
    1998, ApJ, 505, L87
    48: Quasi-Simultaneous Observations of 3C 273 by BeppoSax and ASCA
    Orr, A., Yaqoob, T., Parmar, A. N., Piro, L., White, N. E., & Grandi, P.
    1998, A&A, 337, 685
    49: X-ray Constraints on Accretion and Starburst Processes in Galactic Nuclei I. Spectral Results
    Ptak, A., Serlemitsos, P. J., Yaqoob, T., Mushotzky, R.,
    1999, ApJS, astro-ph/9808159
    50: On the Unusually High Temperature of the Cluster of Galaxies 1E 0657-56
    Yaqoob, T.,
    1999, ApJ, 511, L75
    51: The Properties of the Relativistic Iron K-Line in NGC 3516
    Nandra, K., George, I. M., Mushotzky, R. F., Turner, T. J., & Yaqoob, T.,
    1999, ApJ, 523, L17
    52: X-Ray Properties of the Weak Seyfert 1 Nucleus in NGC 4639
    Ho, L. C., Ptak, A., Terashima, Y., Kunieda, H., Serlemitsos, P. J., Yaqoob, T., Koratkar, A. P.,
    1999, ApJ, 525, 168
    53: A Highly Doppler Blueshifted FE-K Emission Line in the High-Redshift QSO PKS 2149-306
    Yaqoob, T., George, I. M., Nandra, K., Turner, T. J., Zobair, S., & Serlemitsos, P. J.,
    1999, ApJ, 525, L9
    54: A Search for Short Timescale TeV Variability in Mkn501
    Carson, M., McKernan, B., Yaqoob, T., & Fegan, D.,
    1999, Astroparticle Physics, Vol. 11., Issues 1-2, p. 153
    55: X-ray Observations of Optically-Selected, Radio-Quiet Quasars I: The ASCA Results
    George, I. M., Turner, T. J., Yaqoob, T., Netzer, H., Laor, A., Mushotzky, R. F., Nandra, K., & Takahashi, T.,
    1999, astro-ph/9910218
    56: ASCA Observations of "Type 2" LINERs: Evidence for a Stellar Source of Ionization
    Terashima, Y., Ho, L., Ptak, A., Mushotzky, R. F., Serlemitsos, P. J., Yaqoob, T., Kunieda, H.
    1999, astro-ph/9911340
    57: Iron K Line Variability in the Low-Luminosity Active Galactic Nucleus NGC 4579
    Terashima, Y. Ho, L. C.,Ptak, A. F., Yaqoob, T., Kunieda, H., Misaki, K., Serlemitsos, P. J.,
    2000, ApJ, 535, L79.
    58: Short timescale variability in the broadband emission of the blazars Mkn421 and Mkn501
    McKernan, B., Carson, M. J., Yaqoob, T., & Fegan, D. J.,
    2000, Astroparticle Physics, 14, 131.
    59: Variable Iron K alpha Lines in Seyfert 1 Galaxies
    Weaver, K. A., Gelbord, J., & Yaqoob, T.,
    2001, ApJ, 550, 261.
    60: Physical Diagnostics from a Narrow Fe K alpha Emission Line Detected by Chandra in the Seyfert 1 Galaxy NGC 5548
    Yaqoob, T., George, I. M., Turner, T. J., Nandra K., Serlemitsos, P. J., & Mushotzky, R. F.,
    2001, ApJ, 546, 759.
    61: A Broad Fe K alpha Emission Line in the X-Ray Spectrum of the Quasar 3C 273
    Yaqoob, T., & Serlemitsos, P. J.,
    2000, ApJ, 544, L95
    62: Chandra Grating Spectroscopy of the Seyfert Galaxy Ton S180
    Turner, T. J., George, I. M., Yaqoob, T., Kriss, G., Crenshaw, D. M., Kraemer, S., Zheng, W., Wang, J., Nandra, K,
    2001, ApJ, 548, L13.
    63: Quasi-periodic Oscillation in Seyfert Galaxies: Significance Levels. The Case of Markarian 766
    Benlloch, S., Wilms, J., Edelson, R., Yaqoob, T., & Staubert, R.,
    2001, ApJ, 562, L121.
    64: The Spectral Energy Distribution of the Seyfert Galaxy Ton S180
    Turner, T. J., Romano, P., Kraemer, S. B., George, I. M., Yaqoob, T. et al.
    2002, ApJ, 568, 120.
    65: X-Ray Emission from the Nucleus of the Dwarf Elliptical Galaxy NGC 3226
    George, I. M., Mushotzky, R. F., Yaqoob, T., Turner, T. J., Kraemer, S., Ptak, A. F., Nandra, K., Crenshaw, D. M., Netzer, H.,
    2001, ApJ, 559, 167.
    66: The Detection of Circumnuclear X-Ray Emission from the Seyfert Galaxy NGC 3516
    George, I. M., Turner, T. J., Netzer, H., Kraemer, S. B., Ruiz, J., Chelouche, D., Crenshaw, D. M., Yaqoob, T., Nandra, K., & Mushotzky, R. F., ApJ,
    2002, 571, 265.
    67: Narrow Components within the Fe K alpha Profile of NGC 3516: Evidence of the Importance of General Relativistic Effects?
    Turner, T. J., Mushotzky, R. F., Yaqoob, T., George, I. M., Snowden, S. L., Netzer, H., Kraemer, S. B., Nandra, K., & Chelouche, D.,
    2002, ApJ, 574, L123.
    68: The Effect of Changes in the ASCA Calibration on the Fe K Lines in Active Galaxies
    Yaqoob, T., Padmanabhan, U., Dotani, T., & Nandra, K.,
    2002, ApJ, 569, 487.
    69: The Kinematics and Physical Conditions of the Ionized Gas in Markarian 509. I. Chandra High Energy Grating Spectroscopy
    Yaqoob, Tahir, McKernan, Barry, Kraemer, Steven B., Crenshaw, D. Michael, Gabel, Jack R., George, Ian M., & Turner, T. Jane,
    2003, ApJ, 582, 105.
    70: The Kinematics and Physical Conditions of the Ionized Gas in Markarian 509. II. STIS Echelle Observations
    Kraemer, S. B., Crenshaw, D. M., Yaqoob, T., McKernan, B., Gabel, J. R., George, I. M., Turner, T. J., & Dunn, J. P.,
    2003, ApJ, 582, 125.
    71: Fe XXV and Fe XXVI Diagnostics of the Black Hole & Accretion Disk in Active Galaxies: Chandra Time-Resolved Grating Spectroscopy of NGC 7314.
    Yaqoob, T., George, I. M., Kallman, T., Padmanabhan, U., Weaver, K. A., & Turner, T. J.,
    2003, ApJ, 596, 85.
    72: A Warm Hot Intergalactic Medium Towards 3C 120?
    McKernan, B., Yaqoob, T., Mushotzky, R. F., George, I. M., & Turner, T. J.,
    2003, ApJ, 598, L83.
    73: The Kinematics and Physical Conditions of the Ionized Gas in NGC 4593 from Chandra High-Energy Grating Spectroscopy.
    McKernan, B., Yaqoob, T., George, I. M., & Turner, T. J.,
    2003, ApJ, 593, 142.
    74: Simultaneous Ultraviolet and X-Ray Spectroscopy of the Seyfert 1 Galaxy NGC 5548. I. Physical Conditions in the Ultraviolet Absorbers
    Crenshaw, D. M., Kraemer, S. B., Gabel, J. R., Kaastra, J. S., Steenbrugge, K. C., Brinkman, A. C., Dunn, J. P., George, I. M., Liedahl, D. A., Paerels, F. B. S., Turner, T. J., & Yaqoob, T.
    2003, ApJ, 594, 116.
    75: A Puzzling X-Ray Source Found in the Chandra Deep Field-South
    Wang, J., Yaqoob, T., Szokoly, G., Gilli, R., Kewley, L., Mainieri, V., Nonino, M., Rosati, P., Tozzi, P., Zheng, W., Zirm, A., & Norman, C.
    2003, ApJ, 590, L87
    76: The XMM-Newton Iron Line Profile of NGC 3783
    Reeves, J. N, Nandra, K., George, I. M., Pounds, K. A., Turner, T. J., \& Yaqoob, T.
    2004, ApJ, 602, 648.
    77: The Cores of the Fe K Lines in Seyfert I Galaxies Observed by the Chandra High Energy Grating
    Yaqoob, T. & Padmanabhan, U.
    2004, ApJ, 604, 63.
    78: An Extended Scheme for Fitting X-Ray Data with Accretion Disk Spectra in the Strong Gravity Regime
    Dovciak, M., Karas, V., & Yaqoob, T.
    2004, ApJ, in press (astro-ph/0403541)
    79: High Resolution X-Ray Spectroscopy of the Fe K Complex in IC 4329a
    Barry McKernan & Tahir Yaqoob
    2004, ApJ, in press (astro-ph/0401639)
    80: Simultaneous X-ray and Ultraviolet spectroscopy of the Seyfert galaxy NGC 5548. III. X-ray time variability
    Kaastra, J. S., Steenbrugge, K. C., Crenshaw, D. M., Kraemer, S. B., Arav, N., George, I. M., Liedahl, D. A., van der Meer, R. L. J., Paerels, F. B. S., Turner, T. J., & Yaqoob, T.
    2004, ApJ, A&A in press (astro-ph/040446)
    81: Iron K Features in the Quasar E 1821+643: Evidence for Gravitationally Redshifted Absorption
    Tahir Yaqoob & Peter Serlemitsos 2004, ApJ, submitted