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Supernova Surveys
Bruno Leibundgut ESO


One-slide SN 1987A
· KjÔr et al. (arXiv:1003.5684)
­ inner ejecta resolved and mapped in [Si I] and [Fe II] as well as He I lines


Some past supernova surveys
· Historical surveys
­ Zwicky/Caltech/Palomar/POSS
· first systematic searches with the 18" Schmidt · only provider of SNe for a long time · spawned from the Caltech search

­ Asiago (Rosino)/Zimmerwald (Wild) ­ Rev. Evans, McNaught
· extremely successful amateur searches · very limited success (20 SNe in 2 years) · no rate paper every published

­ Las Campanas search (Tammann/Sandage ­ 1984-1986) ­ Berkeley automated search

· first automated search (from Leuschner Observatory) · successful search with photographic plates and CCD follow-up observations · coordinated spectroscopy · basis for SN cosmology by providing the nearby sample (Hamuy et al. 2006)

­ Calan/Tololo SN search (Maza/Hamuy/Phillips/Suntzeff - 1990s)


Nearby supernova surveys
· Nearby ­ z<0.03
mostly focused on prominent, large galaxies "stellar explosions look where the stars are"

­ amateurs

· many, over long periods · well organised (e.g. finding charts, networks, Web pages) · still find interesting objects, often find them early · · · · · KAIT (first Leuschner then Lick) running for over 15 years (11 years with KAIT ­ Weidong Li) >1000 SNe discovered ­ all types best nearby sample for SN rates results are being published
­ Smith et al. 2010, Leaman et al. 2010, Li et al. 2010ab

­ LOSS/LOTOS


Lick Observatory Supernova Search
Total 929 Optimal sample 726 274 37.7% 180 74 116 16.0% 25 324 44.6% 81 Leaman et al. 2010 Li et al. 2010 12 1.6% Ia 372 40.0% Ibc 144 15.5% II 399 42.9% no classification 14 1.6%

Volume limited sample (80Mpc ­Ia; 60Mpc ­ Ibc and II)


Nearby SN surveys
· Nearby (cont.)
­ Center for Astrophysics
· · · · follow-up of interesting objects ­ all types active for the past 2 decades many individual and peculiar objects most extensive nearby SN Ia sample
­ critical for the cosmology (e.g. Riess et al. 1999, Jha et al. 2003, Hicken et al. 2009)

­ Carnegie Supernova Project ­ CSP
· nearby and distant SN follow-up · all types · including on IR light curves
­ Hamuy et al. 2006, Phillips et al. 2007, Folatelli et al. 2010


Nearby SN surveys
­ ROTSE-III
­ Akerlof et al. 2003

­ SN Factory

· see talk by Childress · 600 SNe in two years · mostly unpublished · continuation of SN Factory search in southern sky · new search providing mostly bright supernovae (e.g. 2010ev) · covers 26000 ° · 62 SNe in six months · publish events through VOEvents
­ Drake et al. 2009

­ Quest (Palomar/La Silla) ­ CHASE

­ Catalina Real-Time Transient Survey


Nearby SN surveys
· Palomar Transient Factory
­ see Mark Sullivan's talk ­ >500 SNe in one year
· most not reported to IAU · several peculiar objects detected
­ Avishai Gal-Yam's talk

· `unbiased' statistics

· PanSTARRS-1
­ started this year ­ expect 26000 core-collapse SNe year-1
· most not reported
­ Young et al. 2008


Distant SN surveys
· Intermediate 0.03 ­ SDSS ­ CSP
· see Bob Nichol's talk
­ Kessler et al. 2009 ­ Freedman et al. 2009

· Distant z>0.3

­ Danish distant SN Search

· Danish 1.54m telescope on La Silla · two year search

­ 1 Type Ia (Norgaard-Nielsen et al. 1989), 1 Type II (Hansen et al. 1989)

­ Supernova Cosmology Project

· several projects (NOAO, AAT, CTIO 4m) · started 1991 · CTIO 4m · started 1995

­ Perlmutter et al. 1995, 1997, 1999, Knop et al. 2003

­ High-z SN Search Team
­ Schmidt et al. 1998, Riess et al. 1998, Tonry et al. 2003


Distant SN surveys
· CFHT SN Legacy Survey
­ CFHT+MegaCam
· 4 filters, six years, rolling search all year
­ Astier et al. 2006, Howell et al. 2006, Sullivan et al. 2006ab and many more

­ ESSENCE
· 2 filters, six years, search during 3 months per year
­ Miknaitis et al. 2007, Wood-Vasey et al. 2007, Foley et al. 2008, 2009

­ GOODS HST SN Search/SHOES/PANTS
· highest-z SNe Ia so far (z>1.2)
­ Riess et al. 2004, 2007, 2009, Strolger et al. 2004


Some thoughts on current status
· Current SN discovery rate substantial
­ During the past decade more SNe were observed than during the millennium before (half-point is late 2003) ­ Current searches are extremely effective
· not all supernovae are reported to the IAU any longer · effectively much higher statistics in the last few years

­ Most reported supernovae are classified


Nearby supernovae
· More bright supernovae discovered


Surveys targeting SN progenitors
· SPY
­ search for white dwarf binaries that will merge within a Hubble time

· VLT-FLAMES Survey of Massive Stars · Smartt/VanDyk HST/Keck/VLT programs to detect massive stellar progenitors · X-ray surveys
­ Roelofs et al. 2008 ­ failed in this case, but still promising ­ X-ray all sky surveys ­ eROSITA?


m=30 m=26

Direct observations of SN progenitors
­ white dwarf: M10mag ­ giant: M-4mag
· white dwarf: D16kpc (100kpc for m=30) · giant: D10Mpc (60Mpc for m=30)

· Naively:

350Mpc 56Mpc

280Mpc 45Mpc

· Observable distances (assume m=26)

220Mpc 35Mpc

180Mpc 28Mpc

Poelarends et al. 2008


Supernova Progenitor surveY
· ~1000 white dwarfs checked for radial velocity changes search close binaries
­ are there double degenerate white dwarfs in the solar neighbourhood? ­ discovered ~100 double degenerate systems
Napiwotzki et al. 2007 Geier et al. 2010


Other searches for SN signatures
· -surveys
­ heavily discussed in the community ­ science case for various current and future detectors (e.g. AMANDA or ICECube)

· IR surveys (VVV, VIDEO, UltraVista)
­ just started ­ too early to tell


Future surveys
· Several searches/surveys continue:
­ Amateurs, LOSS, CfA, CHASE, PTF, PanSTARRS-1

· New surveys
­ SkyMapper
· · · · 1.35m telescope, 4 filters, 1250 expect ~400 SNe per year IR follow-up organised to start seriously next year ° `rolling'

­ GAIA transient sources
· expect ~6000 transients during mission


Future distant surveys
· CANDELS/CLASH
­ part of two HST multi-cycle treasury programs ­ z>1.5 SNe for rates
· see EnikÆ RegÆs' talk
­ Riess et al.

· DES
­ several hundred SNe Ia
· see Bob Nichol's talk
­ Bernstein et al. 2008

· PanSTARRS-4/LSST
­ >100000 supernovae per year

· EUCLID/JDEM
­ EUCLID: SNe not main driver (weak lensing and BAO)
· details by Bob Nichol

­ JDEM: BAO and supernovae ­ expect several thousand SNe


Cosmology - do we need more?
· Already in hand
­ >1000 SNe Ia for cosmology ­ constant determined to 5% ­ accuracy dominated by systematic effects
· reddening, correlations, local field, evolution

· Test for variable

­ required accuracy ~2% in individual distances ­ can SNe Ia provide this?
· · · · can the systematics be reduced to this level? homogeneous photometry? further parameters (e.g. host galaxy metalicity) handle >100000 SNe Ia per year?


· Increase in interesting supernovae
­ many more general searches
· remove paradigms

More supernovae

­ possible through the technological progress
· detectors, data storage, data handling and processing

­ Need to keep the overview

· Improved understanding
­ hints on explosion physics ­ statistical samples
· progenitor environments ­ `short fuse' required · rates clues on progenitor systems


· (Do we need a definition of what is a supernova?) · Do we need a central SN database?
­ collect all SN discoveries? ­ IAU database outdated and not capable to supported most new searches

More supernovae

· Follow-up observations
­ classification ­ critical to explore the physics
· · · · · explosions nucleosynthesis asymmetries peculiarities masses