Spectroscopic Sequence Among SNe Ia Peter Nugent(LBNL/UCB)

SNe Ia circa 1993 Phillips ( SNe Ia) and Branch, Fisher & Nugent ( SNe Ia ) were what we had readily available to analyze photometrically and spectroscopically at the time.

Spectroscopic Sequence Nugent et al (1995) – just a temperature sequence... Presumably related to the 56 Ni production.

R(SiII) & R(CaII) Why did we like such an idea? “Simple theories for simple minds...” (E. Quataert) In 1995, we thought we knew almost everything about SNe Ia. Unlike the Sun, which is “so hard to understand due to all the data...” (C. Wheeler)

Chandrasekhar Mass Arnett (1982) – told us that the opacity could drive the lightcurve shape – though he had it wrong.

Sub-Chandra’s? – No. Nugent et al (1997) Models of Woosley & Weaver (1994) and Livne & Arnett (1995) do not match observations spectroscopically. Photometrically they were impressive. However, ~0.2 M  of He blowing up pollutes the spectrum at high velocities.

More data Calán-Tololo search confirmed these relationships. But I never bothered to publish this....

Complacency Why was our “understanding” of SNe Ia so readily accepted? Cosmology. Zwicky + Amateurs KAIT High-Z Searches SNf, SDSS, PTF... Calán-Tololo Search New searches (500/yr) While we had no idea where SNe Ia came from, we wanted to believe we understood them. There were proposals to write...

And more data... Branch, Dang & Baron (2009). This is a much better way to look at the data.

Controlled Search Silverman et al (2012) shows that things are starting to break down. Of note the blue symbols are “high-velocity” SNe Ia.

Instrumentation, system design, first results Law, Kulkarni, Dekany et al PASP L Science plans Rau, Kulkarni, Law et al PASP R 2010 survey status Law et al SPIE 7735 P48: Discovery Engine P48: Discovery Engine P60: Followup P60: Followup Palomar Transient Factory

PTF Science PTF Key Projects Various SNe Dwarf novae Transients in nearby galaxies Core collapse SNe RR Lyrae Solar system objects CVsAGN AM CVn Blazars Galactic dynamics LIGO & Neutrino transients Flare stars Hostless transients Nearby star kinematics Orphan GRB afterglows Type Ia Supernovae Eclipsing stars and planets Tidal events H-alpha ½ sky survey The power of PTF resides in its diverse science goals and follow-up.

PTF Science The power of PTF resides in its diverse science goals and follow-up. Liverpool Telescope

Orphan Afterglow z=1.98!!! FeII, MgII, Ly-α iPTF14yb Cenko et al IPN found a GRB (localization ~ sq. deg.) ~15 min before first detection.....

Stats PTF/iPTF: Spectroscopically Classified Transients 80+ Refereed Papers (all but a handful on single SNe) SNe Ia

R(SiII) from PTF Joe DeRose & Nao Suzuki put together ~200 SNe Ia which we took spectra of near max and had a good measurement of the lightcurve shape. Majority are good, though things are breaking down...

Sub-Chandra’s Revived Scalzo’s work on modeling the ejecta mass, coupled with the UCSB group’s work on shrinking the He layer to ~< 0.05 M  Now there is very little 56 Ni in the outer layers.

Sub-Chandra’s Revived Woosley & Kasen (2011) Outer shell explosions on the left, full star explosed on the right. Nice relationship between M WD and 56 Ni production which, together, drives the lightcurve shape - luminosity relationship. Spectroscopic sequence has the right ingredients and can be maintained.

Sub-Chandra’s Revived Sim et al (2010) And is maintained... R(Si II) works for sub-Chandra’s.

What else is off? Super-Chandra’s Vphot ~ 8000 km/s at 2 days before peak brightness Also observed are CII lines – Howell et al (2006) M bol = S = 1.13

SNF Nothing on Aug 9, mag 17.7 on Aug. 25th, spectrum that night.

SNF ROTSE’s early light-curve + Palomar 200” spectroscopy convinced us that this was something to look at again…

SNF And now we know what it is… a SNLS-03d3bb look-alike. With R~17.4, and z~0.07, this SN has M V =-20 Scalzo et al (2010)

What Next…another one SNF z=0.075

What Next…another one SNF z=0.075

Rates... TBD: (Frohmaier et al, in prep) However, we have ~20 of these in PTF/iPTF out of 1200 SNe Ia. Rare (1%-ish) and associated with heavy star formation. However, likely to be confused with CC SNe at high-z due to their UV- brightness.

Ia-CSM 11kx directly relates the 2002ic and 2005gj SNe to Ia’s and measures a size for the CSM. Dilday et al (2012)

Ia-CSM 11kx directly relates the 2002ic and 2005gj SNe to Ia’s and measures a size for the CSM. RS Oph – like?

Ia-CSM Silverman et al (2013) identifies a group of them in the LOSS and PTF datasets. H-alpha to H-beta ratio is large, weak He I lines, slightly brighter than a SN Ia. Rates are low (1%-ish), but it might be biased by how we have identified them. What if the CSM was 3 times farther away.... See Harris’ talk. Late-time observations!!!

2006bt-10ops Far-flung ( kpc) Maguire et al (2011): 10ops – these are broad, but cool. Si(II) Ratio is very wrong!

2006bt-10ops Far-flung ( kpc) Maguire et al (2011): 10ops – these are broad, but cool. Si(II) Ratio is very wrong!

Exceptional - PTF10zej No large host nearby. Spectroscopically like 1986G/10ops. Why did we “find” this one – no host. We have 4 in PTF...so far.

Rates of these??? Need to look carefully at these, especially wrt cosmology. One thing working for us is that they are quite old, we hope...

Conclusions Observers: Late-time observations, especially for 99aa-91T Publish spectra with lightcurves en masse Start doing rates Be like PTF/KAIT – complete Go beyond simple host correlations - crude Go early as possible – signatures for sub-chandra? Theorists: Smash SNe into CSM H/He & C/O – do spectra and lightcurves Push on the sub-chandra models until they break, we may see other interesting objects (09dav, 10ops, etc.) Do theoretical rates better for these Don’t be pressured by observations Merge theory and observation: See the Goldstein,Thomas & Kasen poster upstairs.