Search for X-ray emission from the Shapley supercluster and the WHIM with Suzaku

Ikuyuki Mitsuishi, Anjali Gupta, Noriko Y. Yamasaki, Yoh Takei, Takaya Ohashi, Kosuke Sato, Massimiliano Galeazzi, J. Patrick Henry, Richard L. Kelley

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Suzaku performed observations of 3 regions in and around the Shapley supercluster: a region located between A3558 and A3556, at ∼0.9 times the virial radii of both clusters, and two other regions at 1° and 4°away from the first pointing. The 4°-offset observation was used to evaluate the Galactic foreground emission. We did not detect significant redshifted Oxygen emission lines (O VII and OV III) in the spectra of all three pointings, after subtracting the contribution of foreground and background emission. An upper limit for the redshifted OV III Kα line intensity of the warm-hot intergalactic medium (WHIM) is 1.5×10 -7 photons s -1 cm -2 arcmin -2, which corresponds to an overdensity of ∼380 (Z/0.1Z ) -1/2(L/3Mpc) -1/2, assuming T=3×10 6 K. We found excess continuum emission in the 1°-offset and on-filament regions, represented by thermal models with kT ∼1 keV and ∼2 keV, respectively. The redshifts of both 0 and that of the supercluster (0.048) are consistent with the observed spectra. The ∼1 keV emission can be also fitted with Ne-rich Galactic (zero redshift) thin thermal emission. Radial intensity profile of 2 keV component suggests contribution from nearby clusters A3558 and A3556, but with significant steepening of the intensity slope in the outer region of A3558.

Original languageEnglish (US)
Title of host publicationSUZAKU 2011 - Exploring the X-Ray Universe
Subtitle of host publicationSuzaku and Beyond
Number of pages2
StatePublished - 2012
EventSuzaku 2011: Exploring the X-Ray Universe: Suzaku and Beyond - Palo Alto, CA, United States
Duration: Jul 20 2011Jul 22 2011

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


OtherSuzaku 2011: Exploring the X-Ray Universe: Suzaku and Beyond
Country/TerritoryUnited States
CityPalo Alto, CA


  • WHIM
  • X-ray
  • cluster
  • supercluster

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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