ULTRASAT% ExploringtheUVtransientsky% vikram/bne_talks/ofek.pdf Eran Ofek! Big Data Dec 17, 2015!...

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Transcript of ULTRASAT% ExploringtheUVtransientsky% vikram/bne_talks/ofek.pdf Eran Ofek! Big Data Dec 17, 2015!...

  • Subtraction

    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    Eran  Ofek   Weizmann  Institute  of  Science  

       

    ULTRASAT   Exploring  the  UV  transient  sky  

  • Subtraction

    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    What is ULTRASAT

    Capabilities

    Science motivation highlight

    SN shock cooling and breakout

    GW EM counterpart

  • Subtraction

    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    Weizmann-Caltech led proposed small space mission (~$100M)

    PIs: Waxman & Kulkarni

    JPL, ISA, IAI, ElOp

    Exploring the UV transient sky

    Designed to:

    SN shock cooling and breakout discovery & alerts

    Studying SN progenitors and physics

    Search & alert for GW EM counterparts in the UV

    Explore the transient sky (e.g., variability, TDE, GRB, QSO)

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    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    33 cm f/1 Schmidt

    NUV band (220-280 nm)

    δ-d CCD (QE~70%)

    Lim mag. 21.8 AB (3x300s; 5σ)

    30 mag arcsec2 (in 3 months)

    FWHM ~24’’

    FOV: 235 deg2

    Volumetric rate: ~380 X GALEX

    ~12 X ZTF

    ~0.2 LSST (but in NUV)

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    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    GEO +300km

    Avoiding geocoronal lines

    Observing continuously 24/7

    Direct & continuous communication

    All data transmission

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    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    For several weeks - All sky survey to 22.8 AB mag.

    Continuous observing of the same FOV for 6 months

    Switching to opposite hemisphere after 6 months

    Mission life time: 2yr

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    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    Pointings

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    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    Image transmission (

  • Subtraction

    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    SN shock breakout & cooling

    GW EM counterpart search

    TDE, GRB, QSO, variability...

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    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    Shock breakout

    occurs when τ~c/v

    Measure R*, E/M, composition

    R*/c  

    di ffu

    sio n   t-­‐4/3  

    L~R*2  

    log  t   ~30  min   ~1  day  

    Lu m in os ity

     

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    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    SN shock cooling – some observations

    2008D (?)

    (Soderberg+08)

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    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    What can we learn?

    Stellar radius

    Explosion energetics (E/M)

    Composition

    Complications: Wind/CSM

    but can derive CSM mass

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    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    Accuracy?

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    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    Why UV?

    The rise time in optical >> rise time in UV

    Therefore, by the time optical reach max light -> T complicated physics

    Removing the degeneracy between E/M and R* requires UV observations

    Probe the temperature

    Brighter in UV in earlier times

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    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    Expectations

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    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    The advantages of a large FOV UV

  • Subtraction

    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    The advantages of a large FOV UV

    1. LIGO/VIRGO error regions ~100 deg2

  • Subtraction

    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    The advantages of a large FOV UV

    2. Ground based observatory can follow up on 1/16 of the ToO within 20min.

    ULTRASAT – can access ~48% of the sky within 20min

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    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    3. EM counterpart properties highly uncertain. However, models predicts UV +blue counterpart at early times

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    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    TDE (>100 event/yr)

    GRB (a few/yr)

    QSO monitoring >20,000

    Stellar monitoring >200,000

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    Eran Ofek

    Big Data Dec 17, 2015

    ΩB  =  0.0447  ±  0.0016  

    Larson+10  

    ULTRASAT capabilities have the potential to revolutionize transient research