I'm an Assistant Professor at the University of Michigan Department of Astronomy. My research focuses on observational study of strong lensing galaxy clusters, determining their mass distributions, and using them as cosmic telescopes to study the background Universe.

Research Group

Traci Johnson - graduate student
Jessica Kellar - graduate student

Postdoc position

In the News:

Hubble Zooms in on a Magnified Galaxy (click to go to http://hubblesite.org)

Read the paper: [PDF | arXiv:1202.0539 | ApJ 746 161]

Also picked up by: NASA | Science Daily | PHYSORG.com | Space Fellowship | hayadan (hebrew) | KICP homepage (full story) | U-M The Record

Current Projects

Giant Arc Surveys in SDSS and RCS1-2
I am leading the SL modeling of cluster lenses from SDSS-GAS and RCS-GA.
In recent years our group at UofC has discovered hundreds of new cluster- and group-size gravitational lenses, in a thorough and statistically-meaningful survey. Some of these are homes for truly spectacular arcs. We aim to study the population of SL clusters via mass measurements using proxies different wavelengths (from Xray through the SZ effect); measure their mass distribution and abundance for cosmological studies; and analyze background galaxies that have been magnified by these clusters, providing the opportunity to study them in an unprecedented detail.

[Limited access wiki page]

Single sources:
  • Koester et al. (2010);
  • Bayliss et al. (2010);
  • SGAS 143845.1+145407: A Big, Cool Starburst at Redshift 0.816, Gladders et al. (2012)

    Cluster/lens properties
  • Mass-concentration relation, Gralla et al. (2010);
  • Spectroscopy paper: Bayliss et al. (2011)
  • Arcs statistics: Bayliss et al. (2011)
  • Mass-metallicity relation in lensed galaxies, Wuyts et al. (2012)

  • Poster presented at Monsters, Inc., SB conference;

    In preparation:
  • A spatially-resolved analysis of the spectrum of the giant arc RCS0327, Rigby et al. in prep
  • SDSS-GAS survey paper, Gladders et al. in prep
  • RCS-GA survey paper, Bayliss et al. in prep

  • SGAS-HST project:
    Our 107 orbit program to image 37 lensing clusters with HST was approved for Cycle 20!
    "Resolving the Star Formation in Distant Galaxies"; PI:Gladders

    Internal website
    RCS 0327
    A giant arc at z~1.7,one of the brightest known at this high redshift, was discovered as part of RCS. Since its discovery it has been the subject of detailed study by our group, including multi-band photometry and spatially-resolved spectra.
  • A Bright, Spatially Extended Lensed Galaxy at z = 1.7 Behind the Cluster RCS2 032727-132623, Wuyts et al. (2010);
  • The Physical Conditions of a Lensed Star-forming Galaxy at z=1.7, Rigby et al. (2011);
  • Source Plane Reconstruction of The Bright Lensed Galaxy RCSGA 032727-132609, Sharon et al. (2012)

  • Hubble Frontier Fields
    Our research group was chosen as one of five research groups to provide the community with preliminary detailed lensing magnification maps of the six Frontier Fields clusters. These public lensing magnification maps will enable the use of the Frontier Fields clusters as powerful cosmic telescopes. Frontier Fields @STScI
    Internal website

    Past Projects

  • Lensing
    Multiply imaged galaxies
    behind the cluster and lensed quasar
    SDSS J1004+4112

    The lensing cluster Abell 1689.
    Links to the paper and full resolution images
    can be found here
  • SN rates in clusters
    A Survey for Supernovae
    in Massive High-Redshift Clusters

    [project page]

  • Rates paper: Sharon et al. (2010)
    [full-res | arXiv:1006.3757]
  • DTD paper [arXiv:1006.3376]
  • WOOTS - Wise Observatory Optical Transient Search
  • Rates paper: Supernovae in Low-Redshift Galaxy Clusters: the Type-Ia Supernova Rate, Sharon et al. (2007)
  • WOOTS SNe paper: Gal-Yam et al. (2008)

  • Theses --

    Chapters from my PhD thesis, titled: "Evolution of Supernova Rates and Dark Matter In Clusters of Galaxies" are published as the following papers:
  • Sharon et al. (2007)
  • Sharon et al. (2010)
  • Maoz, Sharon & Gal-Yam (2010)
  • Sharon et al. (2005)

    My MSc thesis: "SN Counts in Deep HST fields" [ps]

  • Short CV
    Publications [ ADS | astro-ph ]

    Contact --
    903 Dennison
    University of Michigan Department of Astronomy, 500 Church St.
    Ann Arbor, MI 48109
    (734) 936 2079
    E-Mail: kerens @ umich.edu

    Links --

  • University of Michigan Astronomy
  • PPFP
  • LCO
  • KICP
  • UChicago Astro Department
  • Tel Aviv University
  • Wise Observatory

    Outreach --
  • TAU Astronomy Club