Type Ia Supernovae in theNear-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 UBVRIJHK filters is 17, 25, 13, 13, 5, 2, 1, and 0.6 percent, respectively, leaving about 10% unsampled.

But, interstellar extinction is much less seriousin the near-IR:

Band A/AV

J ~0.28 H ~0.18 K ~0.12

This gives us the potential to get much moreaccurate distances than just relying on opticalphotometry.

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)

Based on data in Krisciunas et al. (2000).

Type Ia SNe ofmid-range declinerates seemed todelineate a niceunreddened locus.

AV ~ E(V-K),with in the range1.08 to 1.14 even for a wide rangeof dust properties.

Host of SN 1999cl(M 88) is placed in the Virgo clusteronly if RV ~ 1.55.

Krisciunas et al. (2003)

Peter Hoeflichshowed thatV-H and V-Kcolors of actualSNe are quiteconsistent withmodels.

The V minus near-IRcolors are wellbehaved becausethe V-band lightcurves are stretchableversions of the sametemplate, and thereis a certain uniformityto the IR light curves.

Krisciunas, Phillips, and Suntzeff (2004)

Typically, the near-IR maximum occurs ~3 days beforethe B-band maximum.

Fast decliners that peak in the IR after T(Bmax) aresubluminous in all bands.

Fast decliners that peak in the IR before T(Bmax) haveIR maxima that are almost as bright as the IR maximaof slower decliners (Krisciunas et al. 2009, Stritzingeret al. 2012).

The more slowly declining Type Ia SNe are bluerthan the faster decliners.

Krisciunas et al. (2004b)

Data here are forObjects withm15(B) < 1.02.

Dashed lines arefor mid-rangedecliners.

Krisciunas et al. (2004b) Folatelli et al. (2010)

Pseudo-colors Vmax – Xmax vs. decline rate parameter

SNe 2001el and 2004Swere essentially clonesof each other. Herewe show the filter byfilter offsets of thephotometry, aftercorrections for MWextinction. Somethingis clearly fishy with the U-band data.

Krisciunas et al. (2007)

Krisciunas et al. (2007)

The SN clones2001el and 2004Slet us derive avalue of the excess amount ofV-band extinctionin 2001el comparedto 2004S which tightly constrainsAV and RV. Thisshowed thatmoderately reddenedSNe can have RV much lower than the classic MW valueof 3.1.

RV = 2.15 +/- 0.24

Krisciunas et al. (2003)

As we proceed tolonger wavelengthbandpasses, theslopes of the declinerate relations getshallower andshallower.

Krisciunas, Phillips, and Suntzeff (2004)

First near-IRHubble diagramsof Type Ia SNeat maximumlight.

Krisciunas et al. (2011), Krisciunas (2012)

Excluding possiblesuper-Chandraevents and late-peaking fast decliners,Type Ia SNe arenearly standardcandles in thenear-IR. (Slopes are non-zero at the~2 level.)

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

Kessler et al. (2009) state:

Fig. 30 from Kessler et al. (2009). Most of the objectsthat make up the nearby U-band sample were measuredby the CfA (Riess et al. 1999, Jha et al. 2006, andHicken et al. 2009).

Both the SDSS and the SN Legacy Survey (Conley et al.2011) decided to exclude rest-frame U-band data fromtheir cosmological analysis.

An object at z = 0.7 observed in the R-band is givingus rest frame U-band photons.

Wouldn’t it be nice to eliminate the shift in the equationof state parameter w related to this and use all the photometry from recent and future surveys?

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

There certainly seemsto be a correlation between the S-correctionsand the U-band colorterm.

Ulandolt = uinstr – kU X + (color term)U (u-b)instr + zpU

These light curves were improved considerably:

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

It certainly seemsthat we’ve fixedthe U-bandphotometry ofthese two SNe.

What’s good for the future:

In situ measurements of effective filter profiles (Stubbstunable laser, J.P. Rheault monochromator)

JWST and Euclid

WFIRST – 100 Type Ia SNe per 0.1 redshift binfor most bins between z = 0.4 to 1.2. Filterswill be F111, F141, F178 (1.57-2.00 m). 11.5 deg2 yrsto z ~ 0.8, 2.9 deg2 yrs to z ~ 1.2.

4-m telescope somewhere in Antarctica (could goto 3.6 m and thus get rest-frame near-IR)

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 M and

• Rest-frame ultraviolet photometry good enough for us to use all data in recent surveys and upcoming surveys