Hunting youngest Type Ia SNe in the intermediate Palomar Transient Factory

Yi Cao (Caltech)On behalf of

the intermediate Palomar Transient Factory collaboration

Yi Cao 2

Outline

• Motivation

• the intermediate Palomar Transient Factory– Building young SNe Ia library– Looking for peculiar Type Ia SNe

• Conclusion

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PTF summary

• Discovery machine: Palomar 48-inch telescope• Exposure time: 60 sec• Depth: R~21.0, g~21.5• FoV: 7.2 sq. deg.

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Summary of PTF

• 2009 – 2012– Survey cadence: 3-day, 5-day, 1-day (very limited

time)– Have spectroscopically classified 1818 SNe– 2/3 are Ia’s – Redshift distribution

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Young Type Ia SN physics

• Distribution of 56Ni• Unburned material• Interaction with companion

(Piro & Nakar 2013) (Kasen 2010)9/24/13 Leiden

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iPTF

• Cadence: 3 epochs per night, separated by 45 min• Survey area: 400 – 700 sq. deg., selected to

maximize event rates in nearby galaxies• Depth: R~21 (single epoch), R~21.5 (nightly

stacking)• Real-time process turnaround time: <= 30min• Machine-learning classifier• Alert system for “best” optical transient candidates

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Goals

• Building young Ia library– Automated same-night photometry follow-up with

Palomar 60-inch telescope in Bgriz bands– (coming soon) automated same-night

spectroscopic classification: SEDM– Extensive optical follow-up with resources all over

the world– Follow-up in other energy bands: X-ray/UV, IR,

submm, radio

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What is happening in iPTF

• iPTF13dge (Sept 4, 2013)– [04:05:42]: first P48 epoch– [04:56:31]: first candidate loaded into our DB– [04:59:50]: second P48 epoch– [05:50:08]: second candidate loaded into our DB– [05:51:09]: automated saved– [07:24:31]: LRIS spectrum -> Ia at -15 days– [09:54:07]: Swift started to observe– [15:00:00]: CARMA triggered, VLA DDT proposal submittedWe also triggered our LCOGT program for optical photometric follow-up and informed friends to get IR data with RATIR

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Goals

• Peculiar SNe Ia

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Yi Cao 10(Cao et al. in prep.)9/24/13 Leiden

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To sum up

• iPTF has demonstrated its ability of rapid response to discover and follow up youngest SNe

• In the next two years, iPTF will build a comprehensive light curve and spectrum library of very young Type Ia SNe.

• Peculiarity of SNe Ia

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