1 / 25

The Detection of an Unexplained Emission Line at 3.56 keV

The Detection of an Unexplained Emission Line at 3.56 keV. Esra Bulbul Harvard-Smithsonian Center for Astrophysics. Maxim Markevitch (NASA/GSFC), Adam Foster ( CfA ), Randall Smith ( CfA ), Mike Loewenstein ( NASA/GSFC) , and Scott Randall ( CfA ).

blaine-ingram
Download Presentation

The Detection of an Unexplained Emission Line at 3.56 keV

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Detection of an Unexplained Emission Line at 3.56 keV Esra Bulbul Harvard-Smithsonian Center for Astrophysics Maxim Markevitch (NASA/GSFC), Adam Foster (CfA), Randall Smith (CfA), Mike Loewenstein (NASA/GSFC), and Scott Randall (CfA)

  2. Line Searches in X-ray Observations of Clusters • Largest gravitationally bound aggregations of hot ICM and DM • Gas is enriched mainly via SN explosions by metals produced by stars in galaxies • Weak emission lines are now being discovered through X-ray spectroscopy 2A 0335+096 Werner et al. (2006)

  3. Why Stacking? • 73 galaxy clusters at their rest frame • Increased S/N • 0.01 < z < 0.35 • Smeared non-source features, e.g. instrumental, background XMM-Newton Stamp Images of 73 Galaxy Clusters

  4. Background Before Stacking

  5. Background After Stacking

  6. Detection of An Unidentified Emission Line Energy: XMM - MOS Full Sample 6 Ms Flux: 4.0 ± 0.8 x 10-6 phts cm-2 s-1

  7. with an Additional Gaussian Model… XMM - MOS Full Sample 6 Ms

  8. Detected in Independent PN Observations XMM - PN Full Sample 2Ms

  9. Detected in Fainter 69 Clusters XMM - PN Full Sample 1.8 Ms

  10. Detected in Chandra Observations of the Perseus cluster Chandra ACIS-S 883 ks

  11. Detected in XMM Observations of the Perseus cluster XMM-Newton MOS 317 ks

  12. Confirmation • Boyarsky et al. (2014a, b) detected the line • independent XMM OFFSET observations of the Perseus cluster • M31 • Milky Way Normalized Count Rate cnts/keV/s cnts/keV/s Energy

  13. Unlikely Astrophysical Scenarios • K XVIII line at 3.52 keV Atomic Database Estimates of K XVIII line at 3.52 keV and Ar XVII DR line at 3.62 keV

  14. Unlikely Astrophysical Scenarios • K XVIII line at 3.52 keV • Ar XVII DR line at 3.62 keV Atomic Database Estimates of K XVIII line at 3.52 keV and Ar XVII DR line at 3.62 keV

  15. Unlikely Astrophysical Scenarios • K XVIII line at 3.52 keV • Ar XVII DR line at 3.62 keV Atomic Database Estimates ArXVII DR line at 3.62 keV Based on Ar XVII triplet at 3.12 keV

  16. Unlikely Astrophysical Scenarios • K XVIII line at 3.52 keV • Ar XVII DR line at 3.62 keV • Emission lines of strong hydrogen- and helium-like ions Atomic Database Estimates of K XVIII line at 3.52 keV and Ar XVII DR line at 3.62 keV

  17. Unlikely Astrophysical Scenarios • K XVIII line at 3.52 keV • Ar XVII DR line at 3.62 keV • Emission lines of strong hydrogen- and helium-like ions • Charge exchange Atomic Database Estimates of K XVIII line at 3.52 keV and Ar XVII DR line at 3.62 keV

  18. Unlikely Astrophysical Scenarios • K XVIII line at 3.52 keV • Ar XVII DR line at 3.62 keV • Emission lines of strong hydrogen- and helium-like ions • Charge exchange • Radiative recombination continuum (RRC) feature Atomic Database Estimates of K XVIII line at 3.52 keV and Ar XVII DR line at 3.62 keV

  19. Unlikely Astrophysical Scenarios • K XVIII line at 3.52 keV • Ar XVII DR line at 3.62 keV • Emission lines of strong hydrogen- and helium-like ions • Charge exchange • Radiative recombination continuum (RRC) feature • Any Other Astrophysical Explanations? Atomic Database Estimates of K XVIII line at 3.52 keV and Ar XVII DR line at 3.62 keV

  20. What is the origin? • Could this be a sterile neutrino decay signature? • Warm dark matter candidate sterile neutrinos decay into an active neutrino and emission line • Neutrino Properties • Mass=2Eγ Mass (keV) Mixing angle The diffuse X-ray background (Boyarsky et al. 2006), cluster X-ray (Boyarsky et al. 2006b), BMW (Boyarsky et al. (2007), M31 (Watson et al. 2006), the Tremaine-Gunn bound (Bode et al. 2001), and Fornax dwarf galaxy (Strigari et al. 2006)

  21. Sterile Neutrino vs Astrophysical Line? Astro-H Perseus 1 Ms νbar= 300 km s-1 νDM= 1300 km s-1

  22. Sterile Neutrino Abundance • Sterile neutrinos constitutes ∼19% of the dark matter (Shi & Fuller 1999) • may also be produced by means that do not involve oscillations, such as inflaton or Higgs decay (Kusenko2006; Petraki& Kusenko2008). This detection is consistent with 100% of dark matter composed of sterile neutrinos produced by these mechanisms. • If generated via split seesaw mechanism, this detection indicates that 100% of dark matter composed of sterile neutrinos (Kusenko, Takahashi, & Yanagida 2010).

  23. If you do not want to wait for Astro-H • Alternatives for the Confirmation • Stacked Suzaku and Chandra Observations of large number of galaxy clusters – NASA/ADAP grant (PI: Bulbul) • Deep observations of dwarf spheroidal galaxies • Stacked observations of more Local Group galaxies (cannot nail it if it is a detector artifact) • Deep Chandra observations of the Galactic Center

  24. Limits from Our Detections Mass (keV) 10-11 Mixing angle

  25. Bright Clusters • MOS Observations of the Bright Clusters (Coma, Perseus, Ophiuchus, Centaurus) • Flux: • phtscm-2 s-1 • MOS Observations of the Perseus cluster • phts cm-2 s-1 • MOS Observations of the Perseus cluster(core cut) • phts cm-2 s-1 • not due to a dominant source in the sample, not a background or effective area feature Δχ2 = 17.1 (1 dof) Δχ2 = 15.7 (1 dof)

More Related