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Type Ia Supernovae in the Near-Infrared and the Ultraviolet

Type Ia Supernovae in the Near-Infrared and the Ultraviolet. Kevin Krisciunas. Cook’s Branch Nature Conservancy, April 12, 2012. Why observe in the near-IR?. Howell et al. (2009). At maximum light the fractional flux of a Type Ia SN through

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Type Ia Supernovae in the Near-Infrared and the Ultraviolet

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  1. Type Ia Supernovae in the Near-Infrared and the Ultraviolet Kevin Krisciunas Cook’s Branch Nature Conservancy, April 12, 2012

  2. Why observe in the near-IR? Howell et al. (2009) At maximum light the fractional flux of a Type Ia SN through UBVRIJHK filters is 17, 25, 13, 13, 5, 2, 1, and 0.6 percent, respectively, leaving about 10% unsampled.

  3. But, interstellar extinction is much less serious in the near-IR: Band Al/AV J ~0.28 H ~0.18 K ~0.12 This gives us the potential to get much more accurate distances than just relying on optical photometry.

  4. Elias et al. (1981, 1985) found: • A distinction between Type Ia and Type Ib SNe • Dispersion in absolute magnitudes near maximum • is small for Ia’s • Evidence that V-H and V-K color indices may be • uniform • Presented first Hubble diagram of Type Ia SNe in • the near-IR (H-band mags 20 days after maximum)

  5. Type Ia SNe of mid-range decline rates seemed to delineate a nice unreddened locus. AV ~ a E(V-K), with a in the range 1.08 to 1.14 even for a wide range of dust properties. Host of SN 1999cl (M 88) is placed in the Virgo cluster only if RV ~ 1.55. Based on data in Krisciunas et al. (2000).

  6. Peter Hoeflich showed that V-H and V-K colors of actual SNe are quite consistent with models. Krisciunas et al. (2003)

  7. The V minus near-IR colors are well behaved because the V-band light curves are stretchable versions of the same template, and there is a certain uniformity to the IR light curves. Krisciunas, Phillips, and Suntzeff (2004)

  8. Typically, the near-IR maximum occurs ~3 days before the B-band maximum. Fast decliners that peak in the IR after T(Bmax) are subluminous in all bands. Fast decliners that peak in the IR before T(Bmax) have IR maxima that are almost as bright as the IR maxima of slower decliners (Krisciunas et al. 2009, Stritzinger et al. 2012).

  9. The more slowly declining Type Ia SNe are bluer than the faster decliners. Data here are for Objects with Dm15(B) < 1.02. Dashed lines are for mid-range decliners. Krisciunas et al. (2004b)

  10. Krisciunas et al. (2004b) Folatelli et al. (2010) Pseudo-colors Vmax– Xmax vs. decline rate parameter

  11. SNe 2001el and 2004S were essentially clones of each other. Here we show the filter by filter offsets of the photometry, after corrections for MW extinction. Something is clearly fishy with the U-band data. Krisciunas et al. (2007)

  12. RV = 2.15 +/- 0.24 The SN clones 2001el and 2004S let us derive a value of the excess amount of V-band extinction in 2001el compared to 2004S which tightly constrains AV and RV. This showed that moderately reddened SNe can have RV much lower than the classic MW value of 3.1. Krisciunas et al. (2007)

  13. As we proceed to longer wavelength bandpasses, the slopes of the decline rate relations get shallower and shallower. Krisciunas et al. (2003)

  14. First near-IR Hubble diagrams of Type Ia SNe at maximum light. Krisciunas, Phillips, and Suntzeff (2004)

  15. Excluding possible super-Chandra events and late- peaking fast decliners, Type Ia SNe are nearly standard candles in the near-IR. (Slopes are non-zero at the ~2s level.) Krisciunas et al. (2011), Krisciunas (2012)

  16. We’ve published a lot of U-band photometry but haven’t done a lot with it because of differences of filters from telescope to telescope.

  17. Kessler et al. (2009) state:

  18. Fig. 30 from Kessler et al. (2009). Most of the objects that make up the nearby U-band sample were measured by the CfA (Riess et al. 1999, Jha et al. 2006, and Hicken et al. 2009).

  19. Both the SDSS and the SN Legacy Survey (Conley et al. 2011) decided to exclude rest-frame U-band data from their cosmological analysis. An object at z = 0.7 observed in the R-band is giving us rest frame U-band photons. Wouldn’t it be nice to eliminate the shift in the equation of state parameter w related to this and use all the photometry from recent and future surveys?

  20. Here are some U-band S-corrections we have worked out:

  21. There certainly seems to be a correlation between the S-corrections and the U-band color term. Ulandolt = uinstr – kU X + (color term)U (u-b)instr + zpU

  22. These light curves were improved considerably:

  23. U-band light curves of SNe 2001el and 2004S

  24. It certainly seems that we’ve fixed the U-band photometry of these two SNe.

  25. What’s good for the future: In situ measurements of effective filter profiles (Stubbs tunable laser, J.P. Rheault monochromator) JWST and Euclid WFIRST – 100 Type Ia SNe per 0.1 redshift bin for most bins between z = 0.4 to 1.2. Filters will be F111, F141, F178 (1.57-2.00 mm). 11.5 deg2 yrs to z ~ 0.8, 2.9 deg2 yrs to z ~ 1.2. 4-m telescope somewhere in Antarctica (could go to 3.6 mm and thus get rest-frame near-IR)

  26. Things I’d like to see in the future: • A better understanding of the roles of scattering and • extinction of the light of Type Ia SNe • Hubble diagrams of Type Ia SNe in rest-frame near-IR • frames that reach far enough to measure WM and WL • Rest-frame ultraviolet photometry good enough for us • to use all data in recent surveys and upcoming surveys

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