Ryan C. Hickox


Me on top of the Tour Eiffel

I am a Postdoctoral Fellow in the High Energy Astrophysics Division at the Harvard-Smithsonian Center for Astrophysics. My interests include active galactic nuclei, large-scale structure of the Universe, the cosmic X-ray background, and X-ray binary pulsars.

office: Observatory B-243B
phone: (617) 496-1918
email: rhickox (at) cfa.harvard.edu


research and publications

Chandra image of the 9 square degree NDWFS field in Boötes surveys of active galactic nuclei
I have been studying large populations of infrared-selected active galactic nuclei (AGN) from the wide-field multiwavelength survey in Boötes. We have detected large numbers of dust-obscured quasars using the Spitzer Space Telescope, and measured the masses of dark matter halos in which different classes of AGN reside.

  • Hickox, R.C. et al. 2009, "Clustering of obscured and unobscured quasars", in preparation

  • Brown, M.J.I., Moustakas, J., Caldwell, N., Palamara, D., Cool, R.J., Dey, A., Hickox, R.C., Jannuzi, B.T., Murray, S.S. & Zaritsky, D., 2009, "Active galactic nuclei and the truncation of star formation in K+A galaxies", submitted to ApJ

  • Hickox, R.C. 2009, "Black holes through cosmic time: Exploring the distant X-ray Universe with extragalactic Chandra surveys", Chandra Newsletter cover article, Winter 2009 (arXiv:0904.3543)

  • Watson, C.R., Kochanek, C.S., Forman, W.R., Hickox, R.C. et al. 2009, "The star formation and nuclear accretion histories of normal galaxies in the AGES survey", ApJ, 696, 2206-2219 (arXiv:0903.2219)

  • Hickox, R.C. et al. 2009, "Host galaxies, clustering, Eddington ratios, and evolution of radio-, X-ray-, and infrared-selected AGNs", ApJ, 696, 891-919 (arXiv:0901.4121)

  • Hopkins, P.F., Hickox, R.C., Quataert, E. & Hernquist, L. 2009, "Are most low-luminosity AGN really obscured?", MNRAS in press (arXiv:0901.2936)

  • Hickox, R.C. et al. 2007, "A large population of mid-infrared selected, obscured active galaxies in the Boötes field", ApJ, 671, 1365-1387 (arXiv:0708.3678)

cosmic X-ray background
We have performed the absolute measurement of intensity of the cosmic X-ray background that has not been resolved into point sources by the extremely deep (1 and 2 million second exposure) Chandra Deep Fields. This can constrain a putative population of unresolved X-ray emitting galaxies, as well as put limits on diffuse emission such as the warm-hot intergalactic medium (WHIM) and decay of sterile neutrino dark matter.

  • Hickox, R.C. & Markevitch, M. 2007, "Can Chandra resolve the remaining cosmic X-ray background?", ApJ, 671, 1523-1531 (arXiv:0706.3089)

  • Hickox, R.C. & Markevitch, M. 2007, "Resolving the unresolved cosmic X-ray background in the Chandra Deep Fields", ApJ, 661, 117L-121L (astro-ph/0702556)

  • Abazajian, K.N., Markevitch, M., Koushiappas, S.M., & Hickox, R.C. 2007, "Limits on the radiative decay of sterile neutrino dark matter from the unresolved cosmic and soft X-ray backgrounds", Phys. Rev. D, 75, 063511 (astro-ph/0611144)

  • Hickox, R.C. & Markevitch, M. 2006, "Absolute measurement of the unresolved X-ray background in the 0.5-8 keV band with Chandra", ApJ, 645, 95-114 (astro-ph/0512542)

X-ray pulsars
I am interested in the structure and emission properties of accretion onto X-ray pulsars, especially in systems such as Her X-1, SMC X-1, and LMC X-4 that show evidence for warped, precessing accretion disks. In these systems, reprocessing of the pulsed hard X-ray beam by the inner edge of the disk can allow us to explore the geometry of accretion near the magnetosphere. I have new (Cycle 2) Suzaku observations that will allow us to measure the superorbital variation of LMC X-4.

  • Hickox, R.C. & Vrtilek, S.D. 2005, "Pulse-phase spectroscopy of SMC X-1 with Chandra and XMM-Newton: reprocessing by a precessing disk?", ApJ, 633, 1064-1075 (astro-ph/0506438)

  • Hickox, R.C., Narayan, R., & Kallman, T., 2004, "Origin of the soft excess in X-ray pulsars", ApJ, 614, 881-896 (astro-ph/0407115)

  • Neilsen, J., Hickox, R.C., and Vrtilek, S.D., 2004, "Phase variation in the pulse profile of SMC X-1", ApJ Letters, 616, L135-L138 (astro-ph/0410495)

Full list of publications on ADS and astro-ph, full CV here

teaching


Good old Albert E. I visited African Leadership Academy in Johannesburg, South Africa, as an Expert-in-Residence in astrophysics in March 2009.

I served as Resident Tutor in Physics at Dunster House at Harvard from 2003-2007.

I have been a Teaching Fellow for four Harvard astronomy courses: Science A-35 (Spring 2006), Astro 16 (Spring 2005), Science A-47 (Fall 2004) Astro 45 (Fall 2003), and received Cerificates of Distinction in Teaching in 2004, 2005, and 2006.

I have also served as a Mentor for the SAO Summer Intern Program during the summers of 2004-2006.

Before coming to Harvard, I taught high school physics for two years as the inaugural Peter Ling Fellow at Oundle School in Northamptonshire, England, the largest coed boarding school in the UK.

personal


I enjoy playing music, skiing, and the New England Patriots, among other things.

contact


Ryan C. Hickox
Harvard-Smithsonian Center for Astrophysics
60 Garden Street, MS-67
Cambridge, MA 02138 USA
rhickox (at) cfa.harvard.edu