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. Using new mid-infrared selection techniques with the IRAC camera on the Spitzer Space Telescope, and verified with data from the Chandra X-ray Observatory, we have identified over 600 distant, luminous, obscured AGN, the largest such sample to date.

  • Hickox, R.C. et al. 2008, "Host galaxies, clustering, X-ray spectra, and Eddington ratios of X-ray and radio AGNs at 0.25 < z < 0.8 in AGES", in preparation

  • Hickox, R.C. et al. 2007, "A large population of mid-infrared selected, obscured active galaxies in the Boötes field", ApJ, 671, 1365-1387 (astro-ph/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 (astro-ph/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 an upcoming (Cycle 2) Suzaku program that will observe 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 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