J/ApJ/896/L2 ZTF observations of FRB 180916.J0158+65 (Andreoni+, 2020)
Zwicky Transient Facility constraints on the optical emission from the nearby
repeating FRB 180916.J0158+65.
Andreoni I., Lu W., Smith R.M., Masci F.J., Bellm E.C., Graham M.J.,
Kaplan D.L., Kasliwal M.M., Kaye S., Kupfer T., Laher R.R., Mahabal A.A.,
Nordin J., Porter M., Prince T.A., Reiley D., Riddle R., Van Roestel J.,
Yao Y.
<Astrophys. J., 896, L2 (2020)>
=2020ApJ...896L...2A 2020ApJ...896L...2A
ADC_Keywords: Photometry; Optical; Radio sources
Keywords: Neutron stars ; Transient sources ; Optical bursts ; Radio bursts ;
Compact objects
Abstract:
The discovery rate of fast radio bursts (FRBs) is increasing
dramatically thanks to new radio facilities. Meanwhile, wide-field
instruments such as the 47deg2 Zwicky Transient Facility (ZTF)
survey the optical sky to study transient and variable sources. We
present serendipitous ZTF observations of the Canadian Hydrogen
Intensity Mapping Experiment (CHIME) repeating source
FRB180916.J0158+65 that was localized to a spiral galaxy 149Mpc away
and is the first FRB suggesting periodic modulation in its activity.
While 147 ZTF exposures corresponded to expected high-activity periods
of this FRB, no single ZTF exposure was at the same time as a CHIME
detection. No >3σ optical source was found at the FRB location
in 683 ZTF exposures, totaling 5.69hr of integration time. We combined
ZTF upper limits and expected repetitions from FRB 180916.J0158+65 in
a statistical framework using a Weibull distribution, agnostic of
periodic modulation priors. The analysis yielded a constraint on the
ratio between the optical and radio fluences of η≲200,
corresponding to an optical energy Eopt≲3x1046erg for a fiducial
10Jy.ms FRB (90% confidence). A deeper (but less statistically robust)
constraint of η≲3 can be placed assuming a rate of
r(>5Jy.ms)=1hr-1 and 1.2±1.1 FRB occurring during exposures taken
in high-activity windows. The constraint can be improved with shorter
per-image exposures and longer integration time, or observing FRBs at
higher Galactic latitudes. This work demonstrated how current surveys
can statistically constrain multiwavelength counterparts to FRBs even
without deliberately scheduled simultaneous radio observation.
Description:
The Zwicky Transient Facility (ZTF) on the optical Samuel Oschin
48inch Telescope at Palomar Observatory observed the coordinates of
FRB 180916.J0158+65 serendipitously during its first 2yr of activity
(Figure 1).
ZTF surveys the sky with a typical exposure time of 30s per image. A
total of 683 science images were used in this work, for a total
exposure time of 5.69hr. The images were acquired from 2018 May 31 to
2019 December 228 during the ZTF public survey as well as part of the
ZTF partnership and Caltech surveys (PI: Kulkarni, PI: Prince,
PI: Graham).
Objects:
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RA (ICRS) DE Designation(s)
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01 58 00.75 +65 43 00.3 FRB 180916.J0158+65 = NAME FRB 180916B
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig2.dat 101 683 ZTF observations information and magnitude limits
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See also:
J/other/PASA/33.45 : FRBCAT: The Fast Radio Burst (FRB) Cat. (Petroff+, 2016)
J/ApJ/886/152 : ZTF early observations of Type Ia SNe. I. LCs (Yao+, 2019)
J/ApJ/888/40 : Fast radio bursts with AstroSat/CZTI (Anumarlapudi+, 2020)
Byte-by-byte Description of file: fig2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "Y/M/D" Start.date Date of observation start
12- 13 I2 h Start.h Hour of observation start
14 A1 --- --- [:]
15- 16 I2 min Start.m Minute of observation start
17 A1 --- --- [:]
18- 23 F6.3 s Start.s Second of observation start
25- 34 A10 "Y/M/D" End.date Date of observation end
36- 37 I2 h End.h Hour of observation end
38 A1 --- --- [:]
39- 40 I2 min End.m Minute of observation end
41 A1 --- --- [:]
42- 47 F6.3 s End.s Second of observation end
49- 62 F14.6 d JDStart Julian Date of observation start
64- 77 F14.6 d JDEnd Julian Date of observation end
79- 82 F4.1 s Exp [30] Exposure time
84- 87 F4.2 arcsec Seeing [2/5.4] Seeing
89 A1 --- Filt [gr] Filter
91- 95 F5.2 mag magLim [15/21.8] AB magnitude limit in Filt
97-101 F5.2 mag mag0 [12.7/19.2] Extinction corrected AB magnitude
limit in Filt
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 02-Nov-2021