Detection and study of supernovae with the 4m International Liquid Mirror Telescope BRAJESH KUMAR University of Liège, Belgium ARIES, Nainital, India

OUTLINE: HISTORY BASIC CONCEPTS OF LMTs ILMT Introduction Science with ILMT SUPERNOVAE STUDY WITH ILMT CONCLUSIONS

History of Liquid Mirrors First concept - Ernesto Capocci First working laboratory LMT m Henry Skey Dunedin Observatory, New Zealand Robert Wood – 1909 John Hopkins University Ermanno Borra & Paul Hickson Laval University, Canada University of British Columbia, Canada

 y x x Ac ggg g gg A A A AAA Basic concepts of Liquid Mirrors:

Basic Concepts of Liquid Mirrors :  Parabola : ideal optical system  Constant gravity (g) + Centrifugal Acceleration (  ²x)  Parabolic surface Why ?  Surface Acceleration

Liquids as mirror: Mercury, Gallium, Rubidium, Cesium Mercury: It is liquid above -38.8˚C Reflectivity : 79% - 90% (3100 – ) Inexpensive Surface oxide layer prevents toxic mercury vapors Basic concepts of Liquid Mirrors:

Basic concepts of Liquid Mirrors Detector : CCD camera Time Delay Integration for zenithal telescopes: Tracking by electronically stepping the charges on the CCD Rate of transfer of charges between rows of CCD equal to sidereal rate

INTERNATIONAL LIQUID MIRROR TELECOPE Mirror diameter: 4m Rotation period: 8 sec Focal length: 8m – f/2 Resolution: 0.6’’ FOV: 24’x24’ CCD: 4096 x 4096 pixels (15  m pixels) Filters: i’, r’, g’ (i’ permanently mounted) (i’=762.5 nm, r’=623.1 nm, g’=477 nm) Working temperature: -20˚C to 25˚C Life expectancy: 5 years (Surdej et al. 2006)

9 Structure Mirror CCD Camera Corrector Alignment mechanisms Container Bearing Motor 3-point mount Container Bearing Motor 3-point mount Upper end

Vertical fixed structure focal length = 8 m Air bearing and motor Carbon fiber container (d=4m) DIFFERENT PARTS OF ILMT

SPIN CASTING OF ILMT: Mixing of polyurethane Pouring of polyurethaneFinal mirror shape Taking parabolic shape

INTERNATIONAL LIQUID MIRROR TELESCOPE Collaborating countries: Belgium, Canada, India Location : Devsthal, India 79⁰ 41’ East, 29⁰ 23’ N Altitude : ~ 2400 m Expected first light: September 2010 Devsthal Nainital

SCIENCE WITH ILMT Supernovae Variable objects Gravitational lenses Study of galaxies Data base for follow up

SNe search and related problems Local SNe are rare Sample of galaxies Frequency and magnitude of observations Instruments/techniques The answer is ILMT SUPERNOVAE STUDY WITH ILMT

ILMT : sky strip=24 ˊ galactic latitude~ 30˚ total observed area=146 sq. deg. extragalactic region=72 sq. deg.

Integration time single pass t=1.37 * *n w/f cos(lat) n=number of pixels w= width of pixel f= focal length lat=latitude of the observatory ILMT integration time ~ 100 seconds Limiting magnitude (100 seconds)=22.5 Co-addition will increase the limiting magnitude

Supernovae detection : (0.3<z<0.5) Type Ia 1000 Core collapse 3600 SNe Ib/c 1080 Bright SN Ib/c 216 (Pain et al. 1996, Dahlen et al. 2004, Cappellaro et al. 1999, Strogler et al. 2004) SUPERNOVAE STUDY WITH ILMT

O-IR telescopes, additional benefit For any transient event recognized by ILMT, the 3.6m telescope will be used for further photometric and spectroscopic studies.

CONCLUSIONS ILMT will scan 24’ x 24’ of sky and detect many stellar objects. It will provide unique data base for large conventional telescopes. Thousands of supernovae will be detected ( both type Ia and core collapse) using ILMT. More light on classification of Supernovae. About GRB supernovae relation

THANKS