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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
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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 - 1850 • First working laboratory LMT- 0.35 m Henry Skey- 1872 Dunedin Observatory, New Zealand • Robert Wood – 1909 John Hopkins University • ErmannoBorra & Paul Hickson- 1982 Laval University, Canada University of British Columbia, Canada
Basic concepts of Liquid Mirrors: y x Ac x Ac Ac Ac Ac Ac A A A A A A g g g g g g
Parabola : ideal optical system • Constant gravity (g) + Centrifugal Acceleration (w²x) Parabolic surface • Why ? Surface Acceleration Basic Concepts of Liquid Mirrors:
Basic concepts of Liquid Mirrors: • Liquids as mirror: Mercury, Gallium, Rubidium, Cesium • Mercury: It is liquid above -38.8˚C Reflectivity :79% - 90% (3100 – 13000 ) Inexpensive Surface oxide layer prevents toxic mercury vapors
Basic concepts of Liquid Mirrors Detector : CCD camera Time Delay Integration for zenithaltelescopes: • Tracking by electronicallystepping the charges on the CCD • Rate of transfer of charges betweenrows 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: 4096x4096 pixels (15 mm 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)
Upper end CCD Camera Corrector Alignment mechanisms Structure Container Bearing Motor 3-point mount Mirror
DIFFERENT PARTS OF ILMT Vertical fixed structure focal length = 8 m Carbon fiber container (d=4m) Air bearing and motor
Taking parabolic shape SPIN CASTING OF ILMT: Mixing of polyurethane Pouring of polyurethane Final mirror 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
SUPERNOVAE STUDY WITH ILMT 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=24ˊ 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 STUDY WITH ILMT 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)
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’x24’ 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 http://www.aeos.ulg.ac.be/LMT