Confidence Intervals for the Mean (Large Samples) Larson/Farber 4th ed 1 Section 6.1.
ULTRASAT% ExploringtheUVtransientsky%vikram/bne_talks/ofek.pdfEran Ofek! Big Data Dec 17, 2015! Ω B...
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Subtraction Eran Ofek Big Data Dec 17, 2015 Ω B = 0.0447 ± 0.0016 Larson+10 Eran Ofek Weizmann Institute of Science ULTRASAT Exploring the UV transient sky
Transcript of ULTRASAT% ExploringtheUVtransientsky%vikram/bne_talks/ofek.pdfEran Ofek! Big Data Dec 17, 2015! Ω B...
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
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Eran Ofek Big Data Dec 17, 2015
ΩB = 0.0447 ± 0.0016
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What is ULTRASAT Capabilities
Science motivation highlight SN shock cooling and breakout GW EM counterpart …
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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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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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GEO +300km Avoiding geocoronal lines Observing continuously 24/7 Direct & continuous communication
All data transmission
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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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Pointings
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Image transmission (<200s) Real time processing & alerts (<60s)
Data processing – see recent advances: Zackay & Ofek 2015a,b (+) Zackay, Ofek & Gal-Yam 2016 (-)
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Eran Ofek Big Data Dec 17, 2015
ΩB = 0.0447 ± 0.0016
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SN shock breakout & cooling GW EM counterpart search TDE, GRB, QSO, variability...
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Shock breakout
occurs when τ~c/v Measure R*, E/M, composition
R*/c
diffu
sion t-‐4/3
L~R*2
log t ~30 min ~1 day
Luminosity
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SN shock cooling – some observations 2008D (?)
(Soderberg+08)
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What can we learn? Stellar radius Explosion energetics (E/M) Composition
Complications: Wind/CSM but can derive CSM mass
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Accuracy?
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Why UV? The rise time in optical >> rise time in UV Therefore, by the time optical reach max light -> T<1eV -> 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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Expectations
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The advantages of a large FOV UV
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The advantages of a large FOV UV 1. LIGO/VIRGO error regions ~100 deg2
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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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3. EM counterpart properties highly uncertain. However, models predicts UV+blue counterpart at early times <6 hr.
λ [µ]10-1 100
f λ
1036
1037
1038
bpCaFNlvh.spec
Kasen+ (unpublished)
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TDE (>100 event/yr) GRB (a few/yr) QSO monitoring >20,000 Stellar monitoring >200,000
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ULTRASAT capabilities have the potential to revolutionize transient research
