The most powerful explosions in the Universe Genesis and evolution of Supernova and Gamma-Ray Burst Italian programs at ESO 

EWASS 2012, Symposium 10: "30 years of Italian participation to ESO”

Elena Pian - INAF, Trieste Astronomical Observatory

The detection of SN1987A boosted the Supernova research at ESO

In the 1990s, the ESO programs led by the Supernova group in Padova pioneered and developed the concept of Target-of-Opportunity on “unpredictable” sources

Supernovae

Absolute light curves of 87 SN Ia

Diversity of SNIa

m15(B)

No STD candles !!

Normal SNe Ia follow Phillips relation!

Altavilla et al. 2004

Pskovskii – Phillips relation

normal

vv .. HVG 97 km/s/d HVG 97 km/s/d

LVG 37 km/s/dLVG 37 km/s/dFAINT 87km/s/dFAINT 87km/s/d

Si II 6355Si II 6355ÅÅ velocity evolution velocity evolution

≈≈MMBB

≈≈MMBB+2+2

Photospheric velocities of SN IaPhotospheric velocities of SN Ia

Benetti et al. 2005

Velocity gradient vs. Velocity gradient vs. ΔΔmm1515

HVG

LVG

Faint

Benetti et al. 2005

~0.13Msol~0.13Msol

~0.09Msol~0.09Msol

Applying density structure of W7Applying density structure of W7transform vtransform vexpexp(Si) in mass. (Si) in mass.

ByBy a adding it to the NSE mass, dding it to the NSE mass, wwe e oobtain a constant mass, btain a constant mass, 1.05±0.09 M1.05±0.09 Msunsun , with NO , with NO

DDependence on ependence on mm1515(B)(B)

SNe that produce less SNe that produce less 5656Ni Ni SSynthesize more IMEynthesize more IME

Mazzali et al. 2007

orro diagram!orro diagram! X M (NSE+IME) M (NSE) M (56Ni) M (54Fe + 58Ni)

28 February 1997:

BeppoSAX starts localizing GRBs with arcminute accuracy: the “GRB afterglow era” has started

About 250 GRBs have been followed up with ESO telescopes

~100 keV

Gamma-Ray Bursts

GRB970228: first detection of X-ray and optical afterglow

Van Paradijs et al. and the BeppoSAX team 1997

T0 + 21 hours T0 + 8 days

BeppoSAX detection of X-ray afterglowCosta et al 1997

NTT + SUSI, 13 March 1997

T0 + 8 hours T0 + 3 days

GRB990510 (z = 1.6): optical afterglow

ESO NTT and 3.6m

The time decay is not a single power-law

Israel et al. 1999

Lin. Pol. 1.7±0.2%

VLT+FORS

Covino et al. 1999

The optically brightest GRB

(z = 0.937)

Bloom et al. 2009

(z = 6.29)

(z = 1.6)

GRB080319B: the robotic approach

Racusin et al. 2008

REM+TORTORA

GRB080319B: VLT in Rapid Response Mode with UVES

z = 0.937

Detection of variable absorption lines and identification of 6 absorbers in a velocity range of 100 km/s

D’Elia et al. 2009

Fe II λ2374 Fe II λ2396*

Metallicity of GRB host galaxies

VLT+X-shooter

Piranomonte et al. 2011

25 April 1998:

Gamma-Ray Bursts meet Supernovae

z = 0.0085

GRB980425Supernova 1998bw (Type Ic)

Kinetic energy ~e52 erg

Light Curves of GRB and XRF Supernovae at z < 0.3

Pian et al. 2006Bufano et al. 2012Melandri et al. 2012

Photospheric velocities of Type Ic SNe

Pian et al. 2006Bufano et al. 2012

Summary

A constant burned mass and a common explosion mechanism for Type Ia Supernovae: This may help in understanding their role as standard candles

GRB optical flashes and afterglows: Study of physics (photometry and multiwavelength comparison) and environments (spectroscopy)

GRB and XRF Supernovae: highly energetic Type Ic SNe.

GRB SNe are more luminous than XRF SNe. Is this telling us something about progenitors and remnants?

The Future

NTT Supernova Large ProgramPI: S. Benetti

Public ESO Spectroscopic Survey for Transient Objects (PESSTO)PI: S. Smartt, important Italian role with S. Benetti and S. Valenti

VLT FORS Type Ib/c and IIb Supernova program (late phase)PI: P. Mazzali

VLT X-Shooter GTO TOO program (Denmark, France, Italy The Netherlands)PI: J. Fynbo, Italian Co-PI: S. Covino

VLT X-Shooter GTO program on GRB host galaxiesPI: S. Piranomonte

VLT FORS GRB and X-ray Flash Supernova programPI: E. Pian and M. Della Valle