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Exploring Big Aperture Transient Surveys: Supernovae and Cosmology Insights

This paper reviews the findings from numerous transient surveys focusing on optical phenomena, particularly Type Ia supernovae (SNe Ia), and their implications for cosmological parameters such as the Hubble constant (H0) and dark energy. It discusses the significance of stretch corrections, intrinsic luminosity, and the environmental dependence of SNe. The Supernova Legacy Survey and MACHO project data are analyzed to highlight the identification of host galaxies and the impact of microlensing on dark matter studies. The document emphasizes the challenges posed by various transient sources and the importance of robust identification techniques.

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Exploring Big Aperture Transient Surveys: Supernovae and Cosmology Insights

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  1. Existing Transient Surveys:Optical I:Big Apertures Geoff Bower The Transient Universe: AY 250 Spring 2007

  2. SN Ia SN 2002hp From GOODS The Transient Universe: AY 250 Spring 2007

  3. Type Ia Supernovae and Cosmology H0 = 72 +/- 8 km/s/Mpc Omega_lambda = 0.7 Omega_m = 0.3 Filippenko 2003 The Transient Universe: AY 250 Spring 2007

  4. The Transient Universe: AY 250 Spring 2007

  5. Stretch Correction • Time dilation correction • The more luminous the SN, the longer the timescale The Transient Universe: AY 250 Spring 2007

  6. Corrections to Standard Candle Model Dust and intrinsic luminosity-corrected Filippenko 2003 The Transient Universe: AY 250 Spring 2007

  7. Nearby SNe Calibrate stretch relations Dependence on environment, SN host SN rate Physical understanding of progenitor(s), events, & calibrations Distant SNe Add points to magnitude-redshift relation Goals of Supernova Searches The Transient Universe: AY 250 Spring 2007

  8. Supernova Legacy Survey (SNLS) • Multi-color imaging with CFHT in 4 fields • Simultaneous science with deep field imaging • Square degree FOV • Observations every 3-4 nights • Goal of 700 SN Ia • 0.2 < z < 0.75 • Spectroscopic follow-up with VLT, Keck, Gemini Sullivan et al 2006 Results of 100 spectroscopic SNe The Transient Universe: AY 250 Spring 2007

  9. SN/Galaxy Identification The Transient Universe: AY 250 Spring 2007

  10. Host Galaxy Properties Vigorous star-forming galaxies Normal star-forming galaxies Passive galaxies The Transient Universe: AY 250 Spring 2007

  11. Two Component Origin Prompt component < 0.5 Gyr Tardy ~3 Gyr The Transient Universe: AY 250 Spring 2007

  12. Implications for Further Searches High redshift supernova should exist --- and belong to the prompt class The Transient Universe: AY 250 Spring 2007

  13. Stretch Depends on Galaxy Type The Transient Universe: AY 250 Spring 2007

  14. MACHO Search • Daily photometric LMC monitoring for 5.7 years • Search for microlensing from Galactic halo Alcock et al 2000 The Transient Universe: AY 250 Spring 2007

  15. Dark Matter The Transient Universe: AY 250 Spring 2007

  16. Microlensing Signature Einstein radius Paczynski 1996 The Transient Universe: AY 250 Spring 2007

  17. Microlensing Results Probable Type Ia SN Microlensing events The Transient Universe: AY 250 Spring 2007

  18. Data Selection • ~10 million stars • 21,570 images • 15 sq deg • 2067 days • 330 events • 301 are bumpers • 29 candidates • ~10 supernovae • 13-17 microlensing events total The Transient Universe: AY 250 Spring 2007

  19. MACHO Implications • Microlensing optical depth • ~1 x 10^-7 • Dark halo composed of MACHOs • Tau~5 x 10^-7 • 20% of MW halo mass in < 1 M_sun objects The Transient Universe: AY 250 Spring 2007

  20. Deep Lens Survey Transients • 7 x 4 sq deg fields • 5 years • Multiple imaging • Blanco & Mayall 4 m telescopes at CTIO and KPNO • Pipeline transient processing The Transient Universe: AY 250 Spring 2007

  21. Wide Range of Timescales Probed Becker et al 2004 The Transient Universe: AY 250 Spring 2007

  22. Moving Objects 75% of all transients 3600 total KBOs – 3”/hr NEO – 80”/hr The Transient Universe: AY 250 Spring 2007

  23. Photometrically Variable Objects • Several hundred variable stars • ~100 supernovae The Transient Universe: AY 250 Spring 2007

  24. Optical Transients Without Hosts • OT 20010112 • Spectrum looks like Type II SN at z=0.038 • 3 mag fainter than typical Type II SN • No Host to R > 27.6 mag The Transient Universe: AY 250 Spring 2007

  25. Rapid VariabilityT < 1000 s The Transient Universe: AY 250 Spring 2007

  26. Fast Transients are M dwarfs Kulkarni & Rau 2006 The Transient Universe: AY 250 Spring 2007

  27. The Fast Transient Fog • Blue flares from dwarf stars • Rate ~ 10^8 yr^-1 sky^-1 ~ 10 day^-1 sq deg^-1 • For B < 23.8 mag • GRB rate ~ 10^5 yr^-1 • SN rate ~ 10^8 yr^-1 • Nova rate ~ 10^8 yr^-1 Gpc^-3 The Transient Universe: AY 250 Spring 2007

  28. How to penetrate the fog? • Spectroscopy too expensive • Association with galaxy or cluster not conclusive • Use blue color of flare to select against • Careful field selection • NIR deep imaging The Transient Universe: AY 250 Spring 2007

  29. Summary • Big Transient Searches to Solve Big Problems • Dark matter • Dark energy • Fog of transients makes discovery/identification difficult • Solar system objects • Dwarf stars • One astronomers’s noise… • Matched filter for transient identification is powerful The Transient Universe: AY 250 Spring 2007

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