The ﬁrst interferometric detections of FRBs with …aspen17.phys.wvu.edu/Caleb.pdfManisha Caleb,...

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


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


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


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


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


FRBs at UTMOSTFRB 160317 FRB 160410 FRB 160608

Caleb et al., submitted


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


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


Localisation3-sigma = 15 arcsec x 6 deg

Parkes ~ 160 sq arcmin

UTMOST ~ 56 sq arcmin

2 degrees46 arcsec


FRB160317


If they repeat!



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


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.

The ﬁrst interferometric detections of FRBs with …aspen17.phys.wvu.edu/Caleb.pdfManisha Caleb,...

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