Type ia supernovas
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Type IA Supernovas. Nicklaus Traeden. Outline. Background Cosmology Background Cosmic Distance Ladder Observation History Supernova Physics Technique Current instruments Results Problems Future Projects. Background. Cosmic Distance Ladder //pretty picture here. History.

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Type ia supernovas

Type IA Supernovas

Nicklaus Traeden


Outline

Outline

  • Background

    • Cosmology Background

    • Cosmic Distance Ladder

    • Observation History

    • Supernova Physics

  • Technique

    • Current instruments

    • Results

    • Problems

  • Future Projects


Background

Background

  • Cosmic Distance Ladder

    • //pretty picture here


History

History


Supernovae

Supernovae

  • Supernovae through history

    • Recorded as early as 185 CE

    • Most widely known is SN 1054

      • Produced crab nebula

      • Type II m = -6.00

      • 6500 ly away

    • SN1006 is brightest stellar event

      • Type Ia m = -7.50

      • 7200 ly

    • More discoveries with telescopes

      • SN 1604 – “Kepler’s Star”


Spectral identification

Spectral Identification

Core Collapse Supernovae


White dwarf

White dwarf

  • Electron degeneracy

  • Give relationship between M and R

  • Want mass limit

  • Chandrasekhar Limit ~ 1.4 solar Masses


Background1

Background


Type ia continued

Type Iacontinued

  • 2 12C + 2 16O 56Ni 56Co 56Fe

  • ~1044 J

  • ejecting matter ~6% c

  • Mv = −19.3

    (about 5 billion times brighter than the Sun)

    http://youtu.be/_zw6Eih7QG0


Light curve

Light Curve


Type ia supernovas

  • Stretch factor


Background2

Background

  • Data gathered – S. Perlmutter et al. 1999

    • //graph


Technique

Technique


Technique1

Technique

  • Current Surveys

    • Low z

      • SDSS, LOSS/LOTOS

    • Medium z

      • supernovae legacy survey (SNLS)

      • z<1

    • High z

      • HST

  • Results


Low z surveys

Low Z surveys

  • z<0.03

    • LOSS/LOTOS - over 1000 SNe surveyed

    • Carnegie Supernova Project (CSP) – IR light curves

    • SN Factory – 600 SNe in 2 years

    • Catalina Real-Time Transit Survey

      • Covers 26000 square degrees

    • Amateur

  • Needed for proper calibration of SNe 1a

  • Used to determine SNe rates


Intermediate z surveys

Intermediate z surveys

  • SDSS – z=0.05-0.4

  • CSP – z>0.3


High z surveys

High z surveys

  • Supernova Cosmology Project

  • CFHT + MegaCam

    • 4 filters six years, rolling search

  • GOODS HST SN Search

    • High z (z>1.2)

  • HST Cluster Supernova Survey

    • 0.9 < z < 1.5


Results

Results


Results1

Results

  • Results


Cosmological constraints

Cosmological constraints

  • Consistent with a flat, dark energyw = -1 universe

    • Supernova Legacy Survey 2011


Possible problems

Possible Problems

  • Practical Problems

    • IR, Sne rarity,

  • Astrophysical Uncertainty

  • Systematic Error

    • Calibration uncertainty


Practical problems

Practical Problems

  • SNe 1a are rare.

    • 1 per galaxy per millennia

    • Telescope needs to re-sweep the same area often

  • Want SNe @ high redshift.

    • Shifts spectrum into IR

      • IR is both absorbed and created by the atmosphere.


Astronomical uncertainty

Astronomical Uncertainty

  • All Type IaSNe are the same

  • All light curves are from Type IaSne

    • White dwarf collisions

  • Reddening / extinction


  • Systematic error

    Systematic Error

    • Instrument error

      • Calibration Error

      • Filter uncertainty


    Future projects

    Future Projects

    • WFIRST

      • Microlensing Planet Finder

      • Joint Dark Energy Mission/Omega

      • Near Infrared Sky Surveyor


    Type ia supernovas

    •  a 288-megapixel focal-plane array with a pixel size of 110 milliarcseconds

    • an integral field spectrograph

    • 2.4 m diameter

    • Field ~200 x bigger than HST


    Wfirst

    WFIRST

    • Survey will use 0.5 years of observing over a 2 year period.

    • Projected to measure 2700 Type 1a SNe

      • 0.2<z<1.7


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