The first interferometric detections of FRBs with …aspen17.phys.wvu.edu/Caleb.pdfManisha Caleb,...
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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
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
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
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
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
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
Manisha Caleb, FRB conference, Aspen 2017
FRBs at UTMOSTFRB 160317 FRB 160410 FRB 160608
Caleb et al., submitted
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
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
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
Manisha Caleb, FRB conference, Aspen 2017
If they repeat!
Caleb et al., submitted
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
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
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.