the first interferometric detections of frbs with …aspen17.phys.wvu.edu/caleb.pdfmanisha caleb,...
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![Page 1: The first interferometric detections of FRBs with …aspen17.phys.wvu.edu/Caleb.pdfManisha Caleb, FRB conference, Aspen 2017 The first interferometric detections of FRBs with the](https://reader033.vdocuments.mx/reader033/viewer/2022042304/5ecf32c3d62f4a611c226320/html5/thumbnails/1.jpg)
Manisha Caleb, FRB conference, Aspen 2017
The first interferometric detections of FRBs with the Molonglo radio telescope
Manisha CalebANU/Swinburne
on behalf of the UTMOST collaboration
Credit: Pablo Rosado
FRB conference, Aspen 2017
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Manisha Caleb, FRB conference, Aspen 2017
UTMOST - reborn and refurbished• 18000 m2 telescope. 843
MHz with 31.25 MHz bandwidth and 655 us time resolution.
• Right circularly polarised
• Fully steerable
• ~4x less sensitive that Parkes at full sensitivity
• ~8 deg2 FOV with near exclusive access — great for blind searches and exciting discoveries!
• 7744 ring antennas
• 7744/22 = 352 modules
Credit: Google mapsS
N
EW
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Manisha Caleb, FRB conference, Aspen 2017
UTMOST - reborn and refurbished• 18000 m2 telescope. 843
MHz with 31.25 MHz bandwidth and 655 us time resolution.
• Right circularly polarised
• Fully steerable
• ~4x less sensitive that Parkes at full sensitivity
• ~8 deg2 FOV with near exclusive access — great for blind searches and exciting discoveries!
• 7744 ring antennas
• 7744/22 = 352 modules
Credit: Google mapsS
N
EW
![Page 4: The first interferometric detections of FRBs with …aspen17.phys.wvu.edu/Caleb.pdfManisha Caleb, FRB conference, Aspen 2017 The first interferometric detections of FRBs with the](https://reader033.vdocuments.mx/reader033/viewer/2022042304/5ecf32c3d62f4a611c226320/html5/thumbnails/4.jpg)
Manisha Caleb, FRB conference, Aspen 2017
Science at UTMOST
BURST - The search for fast transients
MAP - The search for slow
transients
Time - Pulsar timing
Credit: S.Bhandari & V.Ravi
Credit:ICRAR
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Manisha Caleb, FRB conference, Aspen 2017
Why UTMOST?
1. Are FRBs astrophysical?
2. What are their population statistics?
BURST - The search for fast transients
Far-field region ~104 km
1 FRB ~ 7 days
Credit:ICRAR
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Manisha Caleb, FRB conference, Aspen 2017
R ≲ 103 events sky-1 day-1
at 843 MHz on 11 Jy ms events
~500 hours @ 7% sensitivity
~225 hours @ 14% sensitivity
Caleb et al., 2016b, MNRAS, 458, 718
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Manisha Caleb, FRB conference, Aspen 2017
FRBs at UTMOSTFRB 160317 FRB 160410 FRB 160608
Caleb et al., submitted
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Manisha Caleb, FRB conference, Aspen 2017
Parameter FRB160317 FRB160410 FRB160608
S/N 13 13 12
Width (ms) 21(7) 4(1) 9(6)
Flux (Jy) > 3.0 > 7.0 > 4.3
Fluence (Jy ms) > 69 > 34 > 37
Isotropic energy (J) ~ 1034 ~ 1032 ~ 1033
DMtotal (pc cm-3) 1165(11) 278(3) 682(7)
DMGalaxy (pc cm-3) 320 58 238
DMexcess (pc cm-3) 845 220 444
DM smearing (ms) 12.6 3.0 7.4
Inferred z ~ 0.7 ~ 0.2 ~ 0.4
Source in BEAM_177 SGR 0755-2933 J0837+0610 J0738-4042
FRB parameters
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Manisha Caleb, FRB conference, Aspen 2017
Follow-up
SkyMapper(Optical)
UTMOST(Radio)
Arecibo(Radio)
GBT(Radio)
ATCA(Radio)
Effelsberg(Radio)
SWIFT(X-ray)
Telescope Time in hours Frequency Results
GBT 16 820 MHz No repeats
Arecibo 12 1400 MHz Data reductionongoing
Effelsberg 4.5 1400 MHz No repeats
UTMOST <=110 843 MHz No repeats
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Manisha Caleb, FRB conference, Aspen 2017
Localisation3-sigma = 15 arcsec x 6 deg
Parkes ~ 160 sq arcmin
UTMOST ~ 56 sq arcmin
2 degrees46 arcsec
Caleb et al., submitted
FRB160317
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Manisha Caleb, FRB conference, Aspen 2017
If they repeat!
Caleb et al., submitted
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Manisha Caleb, FRB conference, Aspen 2017
FRB Rates
• Slightly higher rate could be due to either due to or a combination of:
1. a flat logN-logF curve [N (> Flim) = F ᵅlim] 2. a steep spectral index (spectral index scales as :F∝𝜈ˠ) 3. Small number statistics
UTMOST
1 FRB / 120(60) days
Predicted rate Observed rate
3 FRBs / 170 days*Consistent with Connor et al., 2016 * Nov 2015 to Nov 2016
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Manisha Caleb, FRB conference, Aspen 2017
Fluence completeness
10�1 100 101 102
Width [ms]
100
101
102Pe
akflu
xde
nsit
y[J
y]11 Jy ms
34 Jy ms69 Jy ms
S/N=10
S/N=100
0.65
5m
s 41.9
ms
Detection thresholdWidth range searchedUTMOST FRBsFluence incompleteness
• ~170 days on sky for 3 FRBs
• R (>34 Jy ms) ~ 100 events/sky/day at 843 MHzCaleb et al., submitted
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Manisha Caleb, FRB conference, Aspen 2017 Credit: Pablo Rosado
Summary• First interferometric detections of FRBs at ~ 20%
sensitivity.
• The sky is the limit. Literally! Origin >104 km.
• Current localisation is 3x better than Parkes. Future localisation could be even better with UTMOST-2D!
• Realtime searches have commenced since October 2016 with hires mode.
• 1 FRB every week expected at full sensitivity.