The Transient Sky Eran Ofek CALTECH Shri Kulkarni Arne Rau Mansi Kasliwal Brian Cameron Avishay Gal-Yam Dale Frail Collaborators:

Talk Layout Transients along the EM spectrum (review) Motivation & the future Ongoing optical searches Individual transients (optical) M85 OT SN2006gy Kulkarni, Ofek et al. (2006 Nature submitted ) Rau et al. (2006) Ofek et al. in prep Ofek et al. (2006 ApJL submitted )

Transients along the EM (  -rays) Gamma rays Long-GRBs Short GRBs Soft  -ray repeaters Massive stars NS mergers? Neutron Stars (NS) ?

Transients along the EM (  -rays) Ofek et al. (2006 ApJ accepted) Z=0.09 Progenitor age<10Myr if NS merger: for kick velocity>35km/s

Transients along the EM ( ~cm) Radio Searching for radio transients Levinson, Ofek et al. (2002) Future: ATA SKA Comparison of 2 radio surveys Found: 2 genuine transients Transients in nearby galaxies Gal-Yam, Ofek et al. (2006) Ofek et al. in prep

Transients along the EM (visible) Many searches But usually focused on specific classes… Solar system Supernovae Microlensing …

Motivation New / rare kind of transients Peculiar members of known families Test models Standard candle systematics

Summary of physical motivation

The future - LSST 8.4m mirror 6.5m effective diameter Field of view = 9.65 sq. deg

The future - LSST

LSST details 6 filters: ugrizY ~7000 sq. deg. per night First light: 2013, Cerro Pachon ~1min transients alert Single image: r~24 mag After 10yrs r~28 mag Sky for everyone - No proprietary period!

Back to the present (Our) ongoing searches Nearby clusters Fornax, Perseus SDSS-II cadence improving Follow up Palomar 5m MPG 2.2m LCO 2.5m Palomar robotic 60” Palomar 48” (10 sq. deg) Nearby galaxies survey Palomar robotic 60” Kulkarni, Ofek, Rau, Kasliwal

Another strategy…

Individual transients M85 OT SN2006gy Kulkarni, Ofek et al. (2006) Rau et al. (2006) Ofek et al. in prep Ofek et al. (2006; ApJL submitted) In the past year: Follow-up of 6 transients Examples:

M85 Optical Transient Kulkarni, Ofek et al. (2006; Nature submitted) Rau et al. (2006; ApJL submitted) Ofek et al. in prep

M85 Optical Transient

Width~350km/s

M85 Optical Transient Late time Spitzer observation

M85 Optical Transient Late time Spitzer observation

M85 Optical Transient Green to red color evolution 60 day plateau Peak abs. mag I~-13 Expansion velocity ~350 km/s Cool black-body at late time E~10 47 erg (in 3 months) a-spherical expansion?

M85 Optical Transient …like: M31-RV & V838 Mon

M85 Optical Transient …like: M31-RV & V838 Mon Favored model: Stellar merger (Soker & Tylenda)

M85 Optical Transient Searching for his brothers

SN 2006gy Ofek et al. (2006 ApJL submitted ) Discovered: 2006 Sep 18 (Quimby et al.) H  line AGN(?) - Prieto et al. (2006) Type-IIn supernova (SN) ? Harutyunyan et al. Foley et al. (2006) However, early type galaxy Abs peak ~-22 ~50 days rise time

SN Nucleus Dust lane FWHM ~0.”1 SN 2006gy Ofek et al. (2006 ApJL submitted )

SN 2006gy Ofek et al. (2006 ApJL submitted )

SN 2006gy Ofek et al. (2006 ApJL submitted ) S0 template with E B-V =0.16 extinction day~45 day~7

SN 2006gy Ofek et al. (2006 ApJL submitted )

SN 2006gy Ofek et al. (2006 ApJL submitted ) VLA – no detection Swift/XRT – no detection Chandra (PI: Pooly) Variable X-ray galaxy center

Hybrid IIn/Ia SN (Type-IIa) SN 2002ic ~20 late type galaxy SN 2005gj ~55 blue Irr. M B ~-17 SN 1997cy <30 blue LSB M B ~-17.7 SN 1999E <-19.5 <140 M B ~-15 spiral SN 2006gy ~50 S0 galaxy Name Abs V-mag Rise time [d] Environment SN 2006gy Ofek et al. (2006 ApJL submitted )

energy Total radiated energy ~1.2x10 51 erg during 2 months Type-Ia SN features in spectra Assuming SN2006gy is a type-Ia SN kinetic energy of a Ia SN (~1-2x10 51 erg) radiation SN 2006gy Ofek et al. (2006 ApJL submitted )

Assuming SN2006gy is a type-Ia SN kinetic energy of a Ia SN (~1-2x10 51 erg) radiation Requires: Mass-loss rate ~10 -2 M /yr Over ~100yr Common envelope? (Livio & Riess 2003) SN 2006gy Ofek et al. (2006 ApJL submitted )

Summary First year – “listening” mode: The “known”: 1 LBV(?), 2+1(?) dwarf novae The “known unknown”: Out of 6 targets: The “unknown unknown” M85 OT SN 2006gy Still waiting…

End

Transients along the EM (  -rays) Ofek (2006b); Ofek et al. (2006a) Extragalactic SGRs

M85 Optical Transient

Comparison with other types of transients

Transients along the EM ( ~cm) VLA J

VLA J in NGC 4216

SN 2006gy Ofek et al. (2006) Peak absolute V-band magnitude ~-22.2 Summary Total radiated energy ~1.2x10 51 erg during 2 months Type-Ia SN features in spectra

SDSS-15207

Chandra (PI: Pooley) XRT – no detection VLA – no detection SN 2006gy Ofek et al. (2006 ApJL submitted )

M85 Optical Transient Searching for his brothers in nearby galaxies…