Detecting Neutrino Transients with IceCube & optical Follow-up Observations Marek Kowalski Penn...

Detecting Neutrino Transients with IceCube & optical Follow-up Observations

Marek Kowalski

Penn State, October 2007

Content

• Neutrino bursts: Introduction and science motivation

• Filtering neutrino multiplets, expected rates

• Optical follow up with ROTSE III & Co.

Cosmic Rays & GRBs

Extragalactic

Gamma-Ray Bursts:

GRBs~ 3 1051 ergs x 300/yr/Gpc3

~ 1045 ergs/yr/Mpc3

GRBs could provide environment

and energy to explain the highest

energy cosmic rays! [Waxman 95]

Energy density of extragalactic CR:

CR ~ 1045 ergs/yr/Mpc3

Credit: Meszaros & Murase

MeV neutrinos at collapse

TeV neutrinos from inside the star[Meszaros & Waxman, 2001][Razzaque et al. 2003]

PeV neutrinos from internal shock[Waxman & Bahcall 1997][Gupta & Zhang, 2006][Murase & Nagataki 2006]

PeV-EeV neutrinos from flares[Murase & Nagataki 2006]

EeV neutrinos from external shocks [Dermer 2001][Waxman & Bahcall 2000]

GRBs as sources of high-energy neutrinos Fireball model for long GRBs:

Testing the Supernovae-GRB connection

Observation: Rate of GRBs is just ~1% of SNe Ib/c.

Question: Could there be mildly relativistic jets ( of a few) inside many SNe?

GRBs

SNe ?

Neutrinos could provide the answer:

SN @ 10 Mpc: 30 neutrino events in a cube-kilometer detector!Ando & Beacom, PRL (2005);

Razzaque, Meszaros & Waxman, PRL (2005).Simulation: MacFadyen (2000)

Gravitative collaps of a very massive, rotating star (>25 M):

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Constraints on Quantum Gravity

Energy (TeV)

SNet=10 s

Jacob, Piran 2006



IceCube

IceCube Neutrino-Trigger

day 0

day 1-10

network of opticaltelescopes

optical SN/GRBdetection

Optical NeutrinoFollow-up



Neutrino burst trigger

Doublet background rate:

€

Rdoublet ≈ R2 ΔΩ

2πΔt ≈ 5yr -1

250 a dayFor IceCube

2o x 2o

100 seconds

Background rate of 5 per year,but Field-of-View of 2o x 2o needed.

Other trigger scenarios:

1. Combine -flavors: + e

2. Select high-energy events

optical detection



Search for transient sources:

Supernova (rising lightcurve)

GRB / Supernova identification

Supernova lightcurves

Strizinger et al. (2003)

Search for transient sources:

Supernova (rising lightcurve)

Gamma-Ray Burst (afterglow)

Gamma-Dark Bursts (orphan afterglows)

Time of explosion:


F ~ t-1.2

GRB afterglows

Kahn et al., 2006

10 min

utes

100 second

s

€

σ(F) = 5%⇒ σ (t0) ≈ 0.5 days

Time of explosion:

MK, A. Mohr, 2007


Ando & Beacom flux

Double CoincidenceTriple

coincidence

~20th magnitude detection limit (1 m)~0.003 background

Rat

e [a

rbitr

ary

unit]

Distance [Mpc]

Distribution of Supernovae (simulation)

MK, A. Mohr, 2007

Supernova sensitivity

Ando & Beacom PRL2005

Sensitivity can be doubled by optical follow-up!



Content

• Science motivation and introduction


• Optical follow up with ROTSE III & Co.

Coincident atmospheric neutrinos

Neutrino-Rate ~ 4700/yr ~ 29,300/yr

Doublet-Rate ~ 0.15/yr ~ 5.23/yr time-window: 100 sspace-window: 12<4°

weak CutsNDir≥5, Sigma<2.5

IC9 CutsNDir≥9, Sigma<2.5

(IC 40, cuts not optimzed so far)

Source neutrinosCut Efficiency

5

cut = 2°

cut = 3°

cut = 4°

Doublett-Condition:

12 cut

Localizing the source

median, unweighted

median, weighted

1) Average the two tracks in the multiplet

2)Yet better, use parabolola’s event-wise resolution for weighting:

€

⟨N reco⟩=1

σ 12 + σ 2

2

Nreco,1

σ 12

+Nreco,2

σ 22

⎛

⎝ ⎜

⎞

⎠ ⎟

IC 40, weak cuts

Monitoring detector stability

• Detector stability needs to be monitored on short time scales

• Use of standard IceCube verification and monitoring

techniques

• Decicated variables for burst search

• Event Rate for short time window (e.g. 30 s) • Bin events according direction

QuickTime™ and aGIF decompressor


Sky Monitor: Rates (on trigger level)

Azimuth

Zen

ith

Azimuth

Zen

ith

Sky Monitor: Deviation

Significance map,

€

χ = (n−n )2

σ n2( )



Flasher data to illustrate instability

Significance map,

€

χ = (n−n )2

σ n2( )

Azimuth

Zen

ith



Thanks to Dawn Williams

Off-time window time

Event time

On-time window time

Event time

Off-source/on time: All, but the 3 closest bins

On-source/off-time: Hit bin and 2 closest neighbours

Zenit

hAzimuth

Zenit

h

Azimuth

Catching Deviations

On-time window time

Event time

Off-source/on time: All, but the 3 closest bins

Zenit

hAzimuth

For each event, use the most significant outlier in the two maps to characterize

detector.

Catching Deviations

worst sigma off-source, on-time

Corsika MC

exp. dataflasher

Content

• Science motivation and introduction


• Optical follow up with ROTSE & Co.

The data flow

IceCube

Northern site

Iridium satellites

Send alert

Optical telecopes

SN/GRB

4 x 0.45 mFoV: 2 x 2 rapid follow-up

ROTSE-III

3a, SSO, Australia

3d, TUG, Turkey

3c, H.E.S.S., Namibia

3b, McDonald, TexasQuickTime™ and a

YUV420 codec decompressorare needed to see this picture.

M31

1.85o

Error circle:~60% of IC40~80% of IC80

Primary & secondary optical follow-up Secondary follow-up with

more powerful telescopes

1) Candidates confirmed or excluded with ~100% eff.

2) Spectroscopy for ID

ROTSE, first generation (2008)

Primary follow-up

Large FoV

Conclusion

• Using neutrino events to trigger optical follow-up observations.

• Significant sensitivity improvement for SNe, and perhaps GRBs.

• For some cases, it’s the only way to identify the source!

• Robotic telescopes for follow-up observations exist and even more will come online soon.

Constructing the Doublets

31

Θ1trueΘ1reco

Θ2reco

Θ2true

Θ1reco

Θ2reco

Spacially “coincident” neutrinos

Uncorrelated atmospheric neutrinos

Optical NeutrinoFollow-up







Correlating every neutrino (~105/a)?

Mir

ror

Are

a X

Fie

ld o

f V

iew

Correlating every neutrino (~105/a)?

Next generation of Wide-Field-Imagers: full sky coverage of the optical sky with 3-7 day cadence.

Offline correlation of every neutrino will be possible!

Mir

ror

Are

a X

Fie

ld o

f V

iew

Analysing a ROTSE image

• Of the 83 objects none shows

variations larger than 1 mag

GRB/SN would be identified as

variable object on time-scales of

minutes to days

• 5052 objects identified• Comapare to USNO2.0 reference star

catalog (match to within pixel)• 83 objects not in the catalog

GRB afterglow, 500 s late

Estimate of detection sensitivity from stars in the field

10σ detection

5σ detection

Online Burst Filter and Monitor

Line Fit

Paraboloid Fit

Level1-Preselection

Coincidence Filter

Events

Email AlertEvents

• Reconstruct incoming events with first guess

• Preselection to allow full reconstruction of left-over events

• Filter coincident events

• Check stability using monitoring / verification as well as custom-made tools

Sky Rate Monitor

IceCube Monitor

Verification

ROTSE & Company



• Others:RoboNet, Stella

…

• ROTSE III4 x 0.45 mFoV: 2 x 2 rapid follow-up

Detecting Neutrino Transients with IceCube & optical Follow-up Observations Marek Kowalski Penn...

Documents

Transcript of Detecting Neutrino Transients with IceCube & optical Follow-up Observations Marek Kowalski Penn...