Supernovae: from Stellar Evolution to Cosmology Massimo Turatto Padova - Italia
Outlook Lesson a Introduction to SNe Lesson b SN 1987A in LMC Lesson c SN general properties Lesson d SN progenitors and models Lesson e Thermonuclear SNe Lesson f Core Collapse SNe Lesson g SN rates Lesson h SNe and Cosmology Lesson i SNe and GRB
Lesson a Introduction to Supernovae 1. History 2. Discovery techniques 3. Numerology
Definition of Supernova Explosive event disrupting a star at the end of its (single or binary) evolution, returning to the Inter-Stellar Medium all (or most) the gas synthetized during its evolution and explosion.
Kepler De Stella Nova in Pede Serpentarii SN 1604 Galileo: no significant parallax above the Moon against Aristotle s Cosmology (Digges already for SN 1572)
.. generated by the embrace of Mars and Jupiter at the time of their encounter
Novae and Supernovae Novae observed since millennia in the East and in the West Few in Nebulae (S And 1885) Lundmark (1919) D(And)=200Kpc M SN1885 =-15 Lundmark (1925) It is quite possible that we have to deal with two distinct classes of Novae: one 'upper class' having comparatively few members and reaching an absolute magnitude more or less equal to the absolute magnitude of the system in which they appear: one 'lower class' in the mean 10 magnitudes fainter... Baade & Zwicky 1933-1934 SuperNovae as final stages of Stellar Evolution, sources of cosmic rays and result of creation of NS (!!)
Historical SNe (Stephenson & Green 2005) Investigations of ancient (East and West) chronicles Criteria: 1. Long duration of visibility 2. Fixed location 3. Low b 4. No angular extent 5. Unusual brilliance 6. Independent records 7. (association with SNR)
safe historical supernovae only 8 reliable events: Year Date Con RA Dec mag Comment/SNR 185 AD Cen 14:43.1-62:28-2(-6??) SNR: G135.4-2.3/RCW 86 386 Sgr SNR: G11.2-0.3 (?) 393/396 Sco 17:14-39.8-3 3 radio sources candidates for SNR 1006 Apr 30 Lup 15:02.8-41:57-9(+-1) SNR: PKS 1459-41 1054 Jul 4 Tau 05:34.5 +22:01-6 M1 Crab Nebula 1181 Aug 6 Cas 02:05.6 +64:49-1 3C 58 1572 Nov 6 Cas 00:25.3 +64:09-4 Tycho 1604 Oct 9 Oph 17:30.6-21:29-3 Kepler 1680? 1667? Cas 23:23.4 +58:50 6? Cas A SN (Stephenson & Green 2005; http://www.seds.org/messier/more/mw_sn.html)
SN discovery (SN 1998S)
Image to be searched Reference image Subtracted image SN 2000fc type Ia V=22.4 z=0.42 IAUC7537 Each image is the sum of three 15min exposures The search is based on the comparison of two images taken at different epochs. The image with the best seeing is matched to the other and the reference frame is subtracted using ISIS2.1 package. The difference image is searched for candidates using sextractor. Then we use a scoring algorithm tuned after artificial star experiment to sort the candidates.
Early searches 1885: a bright nova is discovered in the Andromeda Nebula 1936: Zwicky systematic SN search using the new 18 inch Schmidt telescope 1941: Minkowski provisionally divides SNe in type I and II
Palomar 18 inch Schmidt telescope Field of view 9 x 9 deg limit discovery magnitude 16.5 Monitoring 150 nebular fields covering 1/5 of the entire sky visible from Palomar. Sept.1936 -- 1941 19 SNe 1 SN / 135 photographs 1 SN / 8 nights exposure time
1936-1938: 3 SNe First estimate of the SN rate 1/ 600yr /galaxy Zwicky, F. 1938, ApJ 88,529 Palomar 18 inch 1936-1941: 19 SNe - Control time method -SN rate 1/ 359yr /galaxy - independent on galaxy type Zwicky, F. 1942, ApJ 96,28
The golden age 1957: Schmidt telescopes devoted to SN searches in Zimmerwald (CH, P. Wild), Asiago (I, L. Rosino), Tonantzintla (MX, G. Haro, E. Chavira) 1958: Palomar 48-inch Schmidt telescope began SN search 1961: Coordinated international SN search 1968: First SN by an amateur (J. Bennet SN 1968L)
Asiago 40/50cm Schmidt telescope (1958-1992) Field of view 5.5 x 5.5 deg Limit discovery mag 16.0
Asiago 67/92 cm Schmidt telescope (1966 ) Field of view 5.5 x 5.5 deg Limit discovery mag 17.0
1954A Palomar 48 inch Asiago 40/50 Schmidt Zwicky international SN search end of Palomar search 1972E
The modern times 1975: Zwicky Palomar SN search ends 1979: Southern SN search (Maza) 1980: Evans begins his visual SN search (43 SNe) 1981 CCD automated SN search 1986 High redshift SN search z=0.2-0.4 1987 in LMC the brightest SN in the last 4 centuries
MT graduates with a thesis on SNe 1988T z = 0.28 1995at z = 0.66 Ω λ >0 1998bw GRBs end of Palomar search Southern SN searches 1987A
Today LOTOSS 251; LOSS 139 BAOSS 41 QUEST 62 EROS 60 MSACSST 50 + amateurs astronomers
Sky distribution of SNe discovered to date Equatorial coordinates
<1980 511 SNe 1980-1998 944 SNe >=1999 1295 SNe
SN distribution in galactic coordinates
Sky coverage of SN searches
<1980 >=2002
z < 0.01 z > 0.1
Galaxy types
Distribution of SN magnitudes
SN redshift distribution LOTOSS
SNe & spiral galaxy inclination Di Paola et al. (2002) A&A393, L21 A V >6 mag 2002cv Sb-Scd II+Ib/c Ia S0-Sab 2002bo A V =1.5 mag Iband
SN types vs. galaxy types
SN Numerology Asiago supernova Catalogue (Barbon et al. 1984, 1989, 1999) http://web.pd.astro.it/supern/snean.txt pec 2% Tot SNe 3154 (20/6/2005) Ibc 1% Ic 3% Ib 1% II 23% -- 32% I 3% Ia 35%
SN 1987A SN 1998bw
(too) large number of SN types SNIa also in E No SNII, Ib/c in early type galaxies Different distribution among types
High-z SN searches mid 80s: Danish 1.5m (Norgaard-Nielsen et al.) in the 90s: SCP (Perlmutter et al.) High-z SN Search (Schmidt et al.) in the 00s: Essence (Tololo, Smith et al.) Legacy Survey CFHT (PI-less) Ω Λ =0.7 w=p/ρ
Southern Intermediate Redshift ESO SN Search (aimed to the SN rates) WFI@2.2m Telescope aperture: 2.2 m Field of view: 34`x 33` Pixel scale: 0.238 arcsec/pix Effective search area ~5.1 square degrees Spectroscopic follow up with VLT+FORS1/2 12(+13) nights ESO 2.2+WFI 6 nights VLT 21 fields > 500 Gby of raw data > 500 science exposures > 100 candidates
SN search target reference difference - = SN 2000fc type Ia z = 0.42 V=22.4 IAUC7537
Southern Intermediate Redshift ESO SN Search 1. Observations: ESO2.2+WFI 2. SN search: STRESS package Data reduction mscred Image subtraction ISIS2.1 Candidate detection sextractor + score 3. SN confirmation Spectroscopy (VLT+FORS) Photometric history (mysql database) 4. Estimate of the detection efficiency Artificial star experiment Control time 5. Characterization of the galaxy sample: Deep stacked images swarp Photometric redshift hyperz 6. Compute the rate
SN Searches
SN 2001gf Ia z=0.132
SN2001gj II z = 0.27
30% of candidates turn out to be AGNs.
34 spectroscopically confirmed SNe Ia cc Ia/All = 45%
VLT Survey Telescope + OmegaCAM location: Paranal (Chile) size: 2.6 m field of view: 1 x 1 deg Large Binocular Telescope + LBCs location: Mt. Graham (Arizona) size: 2 x 8.2 m field of view: 23 x 23 arcmin 25% of the observing time for the Italian community