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The Transient Sky

The Transient Sky. Eran Ofek CALTECH. Collaborators:. Shri Kulkarni Arne Rau Mansi Kasliwal Brian Cameron Avishay Gal-Yam Dale Frail. Talk Layout. Transients along the EM spectrum (review). Motivation & the future. Ongoing optical searches. Individual transients (optical).

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The Transient Sky

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  1. The Transient Sky Eran Ofek CALTECH Collaborators: Shri Kulkarni Arne Rau Mansi Kasliwal Brian Cameron Avishay Gal-Yam Dale Frail

  2. Talk Layout Transients along the EM spectrum (review) Motivation & the future Ongoing optical searches Individual transients (optical) Kulkarni, Ofek et al. (2006 Nature submitted) Rau et al. (2006) Ofek et al. in prep M85 OT 2006-1 SN2006gy Ofek et al. (2006 ApJL submitted)

  3. Transients along the EM (g-rays) Gamma rays Soft g-ray repeaters Neutron Stars (NS) Long-GRBs Massive stars Short GRBs NS mergers? ?

  4. Transients along the EM (g-rays) Ofek et al. (2006 ApJ accepted) Z=0.09 if NS merger: for kick velocity>35km/s Progenitor age<10Myr

  5. Transients along the EM (l~cm) Radio Searching for radio transients Comparison of 2 radio surveys Levinson, Ofek et al. (2002) Found: 2 genuine transients Gal-Yam, Ofek et al. (2006) Transients in nearby galaxies Ofek et al. in prep Future: ATA SKA

  6. Transients along the EM (visible) Many searches Solar system Supernovae Microlensing … But usually focused on specific classes…

  7. Motivation Peculiar members of known families Test models Standard candle systematics New / rare kind of transients

  8. Summary of physical motivation

  9. The future - LSST 8.4m mirror 6.5m effective diameter Field of view = 9.65 sq. deg

  10. The future - LSST

  11. LSST details 6 filters: ugrizY ~7000 sq. deg. per night Single image: r~24 mag After 10yrs r~28 mag ~1min transients alert First light: 2013, Cerro Pachon Sky for everyone - No proprietary period!

  12. Back to the present (Our) ongoing searches Kulkarni, Ofek, Rau, Kasliwal Palomar 5m MPG 2.2m LCO 2.5m Nearby clusters Fornax, Perseus SDSS-II Palomar robotic 60” Follow up cadence improving Palomar 48” (10 sq. deg) Nearby galaxies survey Palomar robotic 60”

  13. Another strategy…

  14. Individual transients In the past year: Follow-up of 6 transients Examples: Kulkarni, Ofek et al. (2006) Rau et al. (2006) Ofek et al. in prep M85 OT 2006-1 SN2006gy Ofek et al. (2006; ApJL submitted)

  15. M85 Optical Transient 2006-1 Kulkarni, Ofek et al. (2006; Nature submitted) Rau et al. (2006; ApJL submitted) Ofek et al. in prep

  16. M85 Optical Transient 2006-1

  17. M85 Optical Transient 2006-1 Width~350km/s

  18. M85 Optical Transient 2006-1 Late time Spitzer observation

  19. M85 Optical Transient 2006-1 Late time Spitzer observation

  20. M85 Optical Transient 2006-1 Green to red color evolution 60 day plateau Peak abs. mag I~-13 E~1047 erg (in 3 months) Expansion velocity ~350 km/s Cool black-body at late time a-spherical expansion?

  21. …like: M31-RV & V838 Mon M85 Optical Transient 2006-1

  22. …like: M31-RV & V838 Mon M85 Optical Transient 2006-1 Favored model: Stellar merger (Soker & Tylenda)

  23. M85 Optical Transient 2006-1 Searching for his brothers

  24. SN 2006gy Ofek et al. (2006ApJL submitted) Discovered: 2006 Sep 18 (Quimby et al.) Ha line Harutyunyan et al. Foley et al. (2006) Type-IIn supernova (SN) ? However, early type galaxy Abs mag @ peak ~-22 ~50 days rise time AGN(?) - Prieto et al. (2006)

  25. SN 2006gy Ofek et al. (2006ApJL submitted) FWHM ~0.”1 Nucleus SN Dust lane

  26. SN 2006gy Ofek et al. (2006ApJL submitted)

  27. SN 2006gy Ofek et al. (2006ApJL submitted) SN+galaxy @ day~45 SN+galaxy @ day~7 S0 template with EB-V=0.16 extinction

  28. SN 2006gy Ofek et al. (2006ApJL submitted)

  29. SN 2006gy Ofek et al. (2006ApJL submitted) VLA – no detection Swift/XRT – no detection Chandra (PI: Pooly) Variable X-ray source @ galaxy center

  30. SN 2006gy Ofek et al. (2006ApJL submitted) Hybrid IIn/Ia SN (Type-IIa) Abs V-mag Rise time [d] Environment Name SN 2002ic -20.1 ~20 late type galaxy SN 2005gj -20.4 ~55 blue Irr. MB~-17 SN 1997cy -20.1 <30 blue LSB MB~-17.7 SN 1999E <-19.5 <140 MB~-15 spiral SN 2006gy -22.2 ~50 S0 galaxy

  31. energy Total radiated energy ~1.2x1051 erg during 2 months Type-Ia SN features in spectra Assuming SN2006gy is a type-Ia SN kinetic energy of a Ia SN (~1-2x1051 erg) radiation SN 2006gy Ofek et al. (2006ApJL submitted)

  32. Mass-loss rate ~10-2 M /yr SN 2006gy Ofek et al. (2006ApJL submitted) Assuming SN2006gy is a type-Ia SN kinetic energy of a Ia SN (~1-2x1051 erg) radiation Requires: Over ~100yr Common envelope? (Livio & Riess 2003)

  33. Summary First year – “listening” mode: Out of 6 targets: The “known”: 1 LBV(?), 2+1(?) dwarf novae M85 OT 2006-1 The “known unknown”: SN 2006gy The “unknown unknown” Still waiting…

  34. End

  35. Transients along the EM (g-rays) Ofek (2006b); Ofek et al. (2006a) Extragalactic SGRs

  36. M85 Optical Transient 2006-1

  37. M85 Optical Transient 2006-1 Comparison with other types of transients

  38. Transients along the EM (l~cm) VLA J172059+38

  39. VLA J121550+13 in NGC 4216

  40. SN 2006gy Ofek et al. (2006) Summary Peak absolute V-band magnitude ~-22.2 Total radiated energy ~1.2x1051 erg during 2 months Type-Ia SN features in spectra

  41. SDSS-15207

  42. SDSS-15207

  43. SN 2006gy Ofek et al. (2006ApJL submitted) Chandra (PI: Pooley) XRT – no detection VLA – no detection

  44. M85 Optical Transient 2006-1 Searching for his brothers in nearby galaxies…

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