research and publications

Chandra image of the 9 square
degree NDWFS field in Boötes

Full list of publications on ADS, astro-ph, and Google Scholar. My full CV is here.

Active galactic nuclei and galaxy evolution
Much of our group's research focuses on studying large populations of active galactic nuclei (AGN) from multiwavelength surveys. My work aims to explore the links between the fueling of black hole growth and the evolution of host galaxies and large-scale structures.

For an extensive review of AGN and galaxy evolution research motivated by the workshop in Durham on What Drives the Growth of Black Holes?, see our review article (Alexander & Hickox 2012) in New Astronomy Reviews.

For a brief overview of this field geared toward a more general audience, see Supermassive Black Holes and the Growth of Galaxies, which appeared in the UK magazine The Astronomer in March/April 2011.

A sampling of some representative journal articles (over 100 articles total):

  • "Variable Hard X-ray Emission from the Candidate Accreting Black Hole in Dwarf Galaxy Henize 2–10", T. J. Whalen, R. C. Hickox, A. E. Reines, J. E. Greene, G. R. Sivakoff, K. E. Johnson, D. M. Alexander, A. D. Goulding, 2015, ApJ, 806, 37 (arXiv:1504.03331)

  • "The NuSTAR Extragalactic Surveys: Overview and Catalog from the COSMOS Field”, F. M. Civano, R. C. Hickox, et al., 2015, ApJ, 808, 185

  • "Stellar feedback as the origin of an extended molecular outflow in a starburst galaxy", J. E. Geach, R. C. Hickox, A. M. Diamond-Stanic, M. Krips, G. H. Rudnick, C. A. Tremonti, P. H. Sell , A. L. Coil, J. Moustakas, 2014, Nature, 516 68 (arXiv:1412.1091)

  • "A spectroscopic survey of WISE-selected obscured quasars with the Southern African Large Telescope", K. N. Hainline, R. C. Hickox, C. M. Carroll, A. D. Myers, M. A. DiPompeo, L. Trouille, 2014, ApJ, 795, 124 (arXiv:1409.4773)

  • "Black hole variability and the star formation-AGN connection: Do all star-forming galaxies host an AGN?", R. C. Hickox, J. R. Mullaney, D. M. Alexander, C.-T. J. Chen, K. N. Hainline, F. M. Civano, A. D. Goulding, 2014, ApJ, 782, 9 (arXiv:1306.3218)

  • "SALT Long-slit Spectroscopy of Luminous Obscured Quasars: An Upper Limit on the Size of the Narrow-Line Region?", Hainline, K. N., Hickox, R. C., Greene, J., Zakamska, N., Myers, A. D., 2013, ApJ, 774, 145 (arXiv:1307.5852)

  • "High-Velocity Outflows Without AGN Feedback: Eddington-Limited Star Formation in Compact Massive Galaxies", Diamond-Stanic, A.M. et al., 2012, ApJ Letters, 755, 26 (arXiv:1205.2368)

Simple schematic of galaxy and AGN evolution (Hickox et al.~(2009)

  • "The hidden "AGN main sequence": Evidence for a universal black hole accretion to star formation rate ratio since z~2 producing a M_BH-M* relation", Mullaney, J.R. et al., 2012, ApJ Letters, 753, 30 (arXiv:1204.2824)

  • "What Drives the Growth of Black Holes?", Alexander, D. M. & Hickox, R. C., 2012, New Astronomy Reviews (arXiv:1112.1949)

  • "The LABOCA Survey of the Extended Chandra Deep Field South: Clustering of submillimetre galaxies", R.C. Hickox et al. 2012, MNRAS, 421, 284 (arXiv:1112.0321)

  • "GOODS-Herschel: The far-infrared view of star formation in AGN host galaxies since z~3", J. Mullaney et al. 2012, MNRAS, 419, 95 (arXiv:1106.4284)

  • "Clustering of obscured and unobscured quasars in the Bootes field: Placing rapidly growing black holes in the cosmic web", R.C. Hickox et al. 2011, ApJ, 731, 117 (arXiv:1102.4850)

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.

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

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

  • "Limits on the radiative decay of sterile neutrino dark matter from the unresolved cosmic and soft X-ray backgrounds", K. Abazajian et al. 2007, Phys. Rev. D, 75, 063511 (astro-ph/0611144)

  • "Absolute measurement of the unresolved X-ray background in the 0.5-8 keV band with Chandra", R.C. Hickox & M. Markevitch 2006, 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.

  • "Ionized reflection spectra from accretion disks illuminated by X-ray pulsars", D. R. Ballantyne, J. D. Purvis, R. G. Strausbaugh, and R. C. Hickox, 2012, ApJL, 747, 35 (arXiv:1202.2311)

  • "Suzaku X-ray spectra and pulse profile variations during the superorbital cycle of LMC X-4", L.-W. Hung, R.C. Hickox, B.S. Boroson & S.D. Vrtilek 2010, ApJ, 720, 1202-1214 (arXiv:1007.3280)

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

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

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

Ryan C. Hickox
Department of Physics & Astronomy
Dartmouth College
Hanover, NH 03755

Office: 241 Wilder Laboratory
Phone: +1 (603) 646-2962

Last Updated: 6 December 2018
Banner Image: courtesy of Chandra X-ray Center