Detection and study of supernovae with the 4m International Liquid Mirror Telescope

BRAJESH KUMAR

University of Liège, Belgium

ARIES, Nainital, India

OUTLINE:HISTORYBASIC CONCEPTS OF LMTsILMT Introduction Science with ILMTSUPERNOVAE STUDY WITH

ILMTCONCLUSIONS

History of Liquid MirrorsFirst concept - Ernesto Capocci - 1850

First working laboratory LMT- 0.35 m Henry Skey- 1872 Dunedin Observatory, New Zealand

Robert Wood – 1909 John Hopkins University

Ermanno Borra & Paul Hickson- 1982 Laval University, Canada University of British Columbia,

Canada

y

x

xAc

g g g g g g

Ac Ac Ac Ac Ac

AA A A A A

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

gx

dxdy 2

tan fx

gxy

42

222

)2( 2gf

Liquids as mirror: Mercury, Gallium, Rubidium, CesiumMercury: 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:

0A

0A

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: 4mRotation period: 8 secFocal length: 8m – f/2Resolution: 0.6’’FOV: 24’x24’CCD: 4096x4096 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˚CLife expectancy: 5 years

(Surdej et al. 2006)

9

Structure

Mirror

CCD Camera Corrector

Alignment mechanisms

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 polyurethane Final mirror shape

Taking parabolic shape

INTERNATIONAL LIQUID MIRROR TELESCOPECollaborating countries: Belgium, Canada, IndiaLocation : Devsthal, India 79⁰ 41’ East, 29⁰ 23’ N Altitude : ~ 2400 mExpected first light: September 2010 Devsthal

Nainital

SCIENCE WITH ILMT

Supernovae Variable objectsGravitational lensesStudy of galaxiesData base for follow up

SNe search and related problems

Local SNe are rareSample of galaxiesFrequency and magnitude of observationsInstruments/techniques The answer is ILMT

SUPERNOVAE STUDY WITH 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

10 2

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.

CONCLUSIONSILMT 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