University of Tasmania, Australia

Dr Jim Lovell

AuScope VLBI Project Manager

BSc Hons (Tas), PhD (Tas)

Contact Details

General Responsibilities

I am a Senior Research Fellow, currently employed as Project Manager for the AuScope VLBI Project. My research interests are centred around high angular resolution studies Activce Galactic Neuclei (AGN), including inter-stellar scintillation (ISS), applications of AGN studies to improve geodetic VLBI data products, multi-wavelength studies of kpc-scale quasar jets, a Space VLBI AGN brightness temperature survey, and surveys for and observations of gravitational lenses

Career Summary

I have a BSc (with first class honours) and PhD in physics from the University of Tasmania. My PhD thesis work involved an Australia Telescope Compact Array (ATCA) survey for gravitationally lensed quasars as well as detailed observations of a specific gravitational lens PKS 1830-211 with the ATCA and VLBI. Since completing my PhD in 1997, I worked in Japan as a post-doctoral fellow at the Institute of Space and Astronautical Science (ISAS) on the VSOP (VLBI Space Observatory Programme), the first dedicated Space VLBI mission. I was then employed by CSIRO’s Australia Telescope National Facility in Canberra where Icontinued my research and provided support for Radio Astronomy activities at the Canberra Deep Space Communications Complex(Tidbinbilla) from1999 to 2007. Since March 2007 I have been employed as Project Manager for the AuScope VLBI project at UTAS.

Publications

• The Micro-Arcsecond Scintillation-Induced Variability (MASIV) Survey II: The First Four Epochs” 
  Lovell, J.E.J., Rickett, B.J., Macquart, J-P., Jauncey, D.L., Bignall, H.E., Kedziora-Chudczer, L., Ojha, R., Pursimo, T., Dutka, M., Senkbeil, C., Shabala, S. 2008 Astrophysical Journal 689, 108. 
  
  Over 50% of AGN surveyed showed scintillation. We find a lack of scintillating AGN at high redshift suggesting that scatter broadening in the ionised inter-galactic medium may have been detected
  .
• "Rapid Interstellar Scintillation of PKS 1257-326: Two-Station Pattern Time Delays and Constraints on Scattering and Microarcsecond Source Structure" 
  Bignall, H. E., Macquart, J.-P., Jauncey, D. L., Lovell, J. E. J., Tzioumis, A. K., & Kedziora-Chudczer, L. 2006, ApJ, 652, 1050
  
  Simultaneous VLA and ATCA observations of a scintillating AGN over a year were combined with annual modulation data to measure properties of the scattering medium including transverse velocity and asymmetry.
  
  
• "A Chandra Survey of Quasar Jets: First Results" Marshall, H. L., et al. 2005, ApJS, 156, 13
  
  A survey for X-ray jets in AGN. The FR II X-ray jets can all be interpreted as inverse Compton scattering of cosmic microwave background photons by relativistic jet electrons
  
  

• "First Results from MASIV: The Microarcsecond Scintillation-induced Variability Survey" 
  Lovell, J. E. J., Jauncey, D. L., Bignall, H. E., Kedziora-Chudczer, L., Macquart, J.-P., Rickett, B. J., & Tzioumis, A. K. 2003, AJ, 126, 1699

  Results of the first epoch of the MASIV survey for scintillating AGN. 12% of the AGN scintillated on timescales from hours to days but extreme scintillators appear to be rare.

• "The Discovery of H2O Maser Emission in Seven Active Galactic Nuclei and at High Velocities in the Circinus Galaxy" 
  Greenhill, L. J., Kondratko, P. T., Lovell, J. E. J., Kuiper, T. B. H., Moran, J. M., Jauncey, D. L., & Baines, G. P. 2003, ApJ, 582, L11

  The most sensitive southern hemisphere survey for extragalactic water megamasers in AGN accretion disks. Two of the new discoveries has the potential to provide geometric distances.

• "Chandra Discovery of a 100 kiloparsec X-Ray Jet in PKS 0637-752" 
  Schwartz, D. A., et al. 2000, ApJ, 540, L69

  
  A landmark paper in the study of jet emission mechanisms. Reports on the discovery of a large X-ray jet coincident with the radio and with optical counterparts.

• "The VSOP 5 GHz AGN Survey I. Compilation and Observations" 
  Hirabayashi, H., et al. 2000, PASJ, 52, 997

  
  Baselines to the VSOP spacecraft allowed for the highest lower-limit brightness temperature measurements so far. 50% of the observed AGN had brightness temperatures in excess of the inverse Compton limit.

• "The Time Delay in the Gravitational Lens PKS 1830-211" 
  Lovell, J. E. J., Jauncey, D. L., Reynolds, J. E., Wieringa, M. H., King, E. A., Tzioumis, A. K., McCulloch, P. M., & Edwards, P. G. 1998, ApJ, 508, L51

  The Australia Telescope Compact Array was used to monitor the brightness of the two gravitationally lensed images in PKS1830-211. The time delay was measured, providing constraints on the Hubble constant.

• "The Subparsec-Scale Structure and Evolution of Centaurus A: The Nearest Active Radio Galaxy" 
  Tingay, S. J., et al. 1998, AJ, 115, 960

  Southern hemisphere VLBI observations of the nearby active galaxy Centaurus A. Motion of the jet components is slow ~0.1c and appear consistent with pattern changes in an underlying relativistic flow.

• "Relativistic Motion in a Nearby Bright X-Ray Source" 
  Tingay, S. J., et al. 1995, Nature, 374, 141

  Southern hemisphere VLBI observations of a Galactic transient X-ray source GRO J1655-40 revealed superluminal radio jets following a high accretion-rate epoch.

Research Interests

I have authored or co-authored 172 papers of which 83 are in refereed journal publications. Highlights from these research programs include:

• The first large-scale survey for scintillating AGN, the Micro-Arcsecond Scintillation-Induced Variability (MASIV) survey which has now identified over 200 variable sources and found evidence for scattering in the inter-galactic medium. (Lovell et al 2003, Lovell et al 2008).
• Measuring the brightness temperature distribution of a large sample of AGN with VSOP. (Lovell et al 2004, Scott et al 2004, Horiuchi et al 2004, Dodson et al 2008)
• The serendipitous discovery of a kpc-scale X-ray jet in PKS 0637-752 for which I was responsible for the follow-up radio observations (Lovell et al 2000, Schwartz et al 2000 ApJ 540, Chartas et al 2000 ApJ 542, Edwards et al 2006). This has led to a collaborative effort to understand the nature of X-ray jets through multi-wavelength observations with space- and ground-based observatories (Marshall et al 2005). The paper describing the discovery of the X-ray jet in PKS 0637-752 has 117 citations, and launched a new field of AGN studies that remains the subject of widespread community interest.
• A measurement of the time delay in the gravitational lens PKS 1830-211 (Lovell et al 1998) and detection of an intervening galaxy along the line of sight (Lovell et al 1996)
• The discovery of three new gravitationally lensed systems (Winn et al 2000, Winn et al 2002a, Winn et al 2002b)
• Discovery of 16 new extragalactic water maser systems with the Tidbinbilla 70 m radio telescope (Greenhill at al 2003, Kondratko et al 2006)

I am a member of the International Astronomical Union and a Fellow of the Astronomical Society of Australia.

Research Areas

• Radio Astronomy