J/ApJ/905/145 ZTF candidate counterparts to 13 GW follow-up (Kasliwal+, 2020)
Kilonova luminosity function constraints based on Zwicky Transient Facility
searches for 13 neutron star merger triggers during O3.
Kasliwal M.M., Anand S., Ahumada T., Stein R., Sagues Carracedo A.,
Andreoni I., Coughlin M.W., Singer L.P., Kool E.C., De K., Kumar H.,
AlMualla M., Yao Y., Bulla M., Dobie D., Reusch S., Perley D.A., Cenko S.B.,
Bhalerao V., Kaplan D.L., Sollerman J., Goobar A., Copperwheat C.M.,
Bellm E.C., Anupama G.C., Corsi A., Nissanke S., Agudo I., Bagdasaryan A.,
Barway S., Belicki J., Bloom J.S., Bolin B., Buckley D.A.H., Burdge K.B.,
Burruss R., Caballero-Garcia M.D., Cannella C., Castro-Tirado A.J.,
Cook D.O., Cooke J., Cunningham V., Dahiwale A., Deshmukh K., Dichiara S.,
Duev D.A., Dutta A., Feeney M., Franckowiak A., Frederick S., Fremling C.,
Gal-Yam A., Gatkine P., Ghosh S., Goldstein D.A., Golkhou V.Z., Graham M.J.,
Graham M.L., Hankins M.J., Helou G., Hu Y., Ip W.-H., Jaodand A.,
Karambelkar V., Kong A.K.H., Kowalski M., Khandagale M., Kulkarni S.R.,
Kumar B., Laher R.R., Li K.L., Mahabal A., Masci F.J., Miller A.A.,
Mogotsi M., Mohite S., Mooley K., Mroz P., Newman J.A., Ngeow C.-C.,
Oates S.R., Patil A.S., Pandey S.B., Pavana M., Pian E., Riddle R.,
Sanchez-Ramirez R., Sharma Y., Singh A., Smith R., Soumagnac M.T.,
Taggart K., Tan H., Tzanidakis A., Troja E., Valeev A.F., Walters R.,
Waratkar G., Webb S., Yu P.-C., Zhang B.-B., Zhou R., Zolkower J.
<Astrophys. J., 905, 145 (2020)>
=2020ApJ...905..145K 2020ApJ...905..145K
ADC_Keywords: Gravitational wave; Stars, neutron; Black holes; Redshifts;
Photometry, ugriz
Keywords: Neutron stars ; Black holes ; Gravitational waves ;
Nucleosynthesis ; R-process ; Compact objects ; Spectroscopy ;
Sky surveys ; Photometry
Abstract:
We present a systematic search for optical counterparts to
13 gravitational wave (GW) triggers involving at least one neutron
star during LIGO/Virgo's third observing run (O3). We searched binary
neutron star (BNS) and neutron star black hole (NSBH) merger
localizations with the Zwicky Transient Facility (ZTF) and undertook
follow-up with the Global Relay of Observatories Watching Transients
Happen (GROWTH) collaboration. The GW triggers had a median
localization area of 4480deg2, a median distance of 267Mpc, and
false-alarm rates ranging from 1.5 to 10-25yr-1. The ZTF coverage
in the g and r bands had a median enclosed probability of 39%, median
depth of 20.8mag, and median time lag between merger and the start of
observations of 1.5hr. The O3 follow-up by the GROWTH team comprised
340 UltraViolet/Optical/InfraRed (UVOIR) photometric points, 64 OIR
spectra, and three radio images using 17 different telescopes. We find
no promising kilonovae (radioactivity-powered counterparts), and we
show how to convert the upper limits to constrain the underlying
kilonova luminosity function. Initially, we assume that all GW
triggers are bona fide astrophysical events regardless of false-alarm
rate and that kilonovae accompanying BNS and NSBH mergers are drawn
from a common population; later, we relax these assumptions. Assuming
that all kilonovae are at least as luminous as the discovery magnitude
of GW170817 (-16.1mag), we calculate that our joint probability of
detecting zero kilonovae is only 4.2%. If we assume that all kilonovae
are brighter than -16.6mag (the extrapolated peak magnitude of
GW170817) and fade at a rate of 1 mag day-1 (similar to GW170817), the
joint probability of zero detections is 7%. If we separate the NSBH
and BNS populations based on the online classifications, the joint
probability of zero detections, assuming all kilonovae are brighter
than -16.6mag, is 9.7% for NSBH and 7.9% for BNS mergers. Moreover, no
more than <57% (<89%) of putative kilonovae could be brighter than
-16.6mag assuming flat evolution (fading by 1 mag day-1) at the 90%
confidence level. If we further take into account the online
terrestrial probability for each GW trigger, we find that no more than
<68% of putative kilonovae could be brighter than -16.6mag. Comparing
to model grids, we find that some kilonovae must have Mej<0.03M☉,
Xlan>10-4, or φ>30° to be consistent with our limits. We
look forward to searches in the fourth GW observing run; even
17 neutron star mergers with only 50% coverage to a depth of -16mag
would constrain the maximum fraction of bright kilonovae to <25%.
Description:
In Table 1, we summarize 13 gravitational wave (GW) triggers during
the LIGO/Virgo's third observing run (O3; from 2019-April to 2020-March)
for which we obtained either serendipitous or triggered coverage with
the Zwicky Transient Facility (ZTF). See Section 2.
We used the 1 and 2m telescopes available at the Las Cumbres
Observatory (LCO) global network to follow up sources discovered with
the ZTF. The images obtained with the Liverpool Telescope (LT) were
acquired using the IO:O camera with the Sloan griz filter set. We used
the Electronic Multiplier CCD camera at Kitt Peak EMCCD Demonstrator
(KPED) to take hour-long exposures in the r band to follow up
candidates. We obtained data with the GMOS-N, mounted on the
Gemini-North 8m telescope on Maunakea. We used the Lulin One-meter
Telescope (LOT) at the Lulin Observatory in Taiwan. We also used the
0.7m robotic GROWTH-India telescope (GIT) equipped with a 4096x4108
pixel back-illuminated Andor camera for LVC event follow-up during O3.
Additionally, we obtained photometric data with the Spectral Energy
Distribution Machine (SEDM) on the P60 telescope. We used the imaging
capabilities of the OSIRIS camera at the Gran Telescopio Canarias
(GTC) to obtain 60s exposures in the r band. We obtained follow-up
imaging of candidates with the Wafer Scale Imager for Prime (WASP) and
the Wide-field Infrared Camera (WIRC), both on the P200 telescope. We
obtained imaging of one candidate using the Low Resolution Imaging
Spectrometer (LRIS), mounted at the Keck I telescope. We used the
Large Monolithic Imager (LMI) on the 4.3m Lowell Discovery Telescope
(LDT) at Happy Jack, Arizona, to follow up the ZTF discoveries. We
used the Ultraviolet/Optical Telescope (UVOT) mounted on the Neil
Gehrels Swift Observatory to follow up interesting sources and track
down their UV evolution. We observed candidate counterparts of
S200213t using the Astrophysical Research Consortium Telescope Imaging
Camera (ARCTIC) at the APO 3.5m. See Appendix A.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 78 13 Summary of ZTF follow-up of 13 gravitational wave
(GW) triggers in LIGO/Virgo's third observing
run (O3)
table2.dat 96 15 List of candidate counterparts to S190426c
table3.dat 91 7 List of candidate counterparts to S190901ap
table4.dat 96 4 List of candidate counterparts to S190910d
table5.dat 90 11 List of candidate counterparts to S190910h
table6.dat 86 1 List of candidate counterparts to S190923y
table7.dat 78 3 List of candidate counterparts to S190930t
table8.dat 87 7 List of candidate counterparts to S191205ah
table9.dat 102 18 *List of candidate counterparts to S191213g
table10.dat 100 19 List of candidate counterparts to S200213t
table11.dat 64 18 Follow-up photometry for S190426c candidates
table12.dat 64 66 Follow-up photometry for S190901ap candidates
table13.dat 64 7 Follow-up photometry for S190910d candidates
table14.dat 64 9 Follow-up photometry for S190910h candidates
table15.dat 64 8 Follow-up photometry for S190930t candidates
table16.dat 64 3 Follow-up photometry for S191205ah candidates
table17.dat 64 30 Follow-up photometry for S191213g candidates
table18.dat 64 32 Follow-up photometry for S200213t candidates
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Note on table9.dat: reported in 2019GCN.26424....1A 2019GCN.26424....1A and 2019GCN.26437....1S 2019GCN.26437....1S
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See also:
VII/285 : Gaia DR2 quasar and galaxy classification (Bailer-Jones+, 2019)
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
J/AJ/141/97 : SDSS DR7 M dwarfs (West+, 2011)
J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)
J/ApJ/806/52 : 8 Fermi GRB afterglows follow-up (Singer+, 2015)
J/A+A/593/A68 : PTF12os & iPTF13bvn spectra and light curves (Fremling+, 2016)
J/ApJ/848/L29 : Opt. follow-up of GW170817 counterpart (Diaz+, 2017)
J/ApJ/848/L16 : Counterpart of GW170817. I. DECam obs. (Soares-Santos+, 2017)
J/ApJS/234/23 : The WISE AGN candidates catalogs (Assef+, 2018)
J/other/Sci/362.201 : iPTF 14gqr (SN 2014ft) photometry (De+, 2018)
J/ApJ/880/7 : Census of the Local Universe survey. I. CLU-Ha (Cook+, 2019)
J/A+A/631/A147 : Transient processing and analysis using AMPEL (Nordin+, 2019)
J/ApJ/886/152 : ZTF early observations of Type Ia SNe. I. LCs (Yao+, 2019)
J/ApJ/890/131 : Follow-up of cand. counterparts of S190814bv (Andreoni+, 2020)
J/ApJ/895/32 : Zwicky Transient Facility BTS. I. (Fremling+, 2020)
http://www.wis-tns.org/ : Transient Name Server (TNS) home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- GW Name of the source
11- 15 A5 /yr FAR GW false-alarm rate (FAR)
17- 18 I2 % Pt [1/97] Probability that the event is terrestrial
20- 24 I5 deg2 Size [23/24264] Total size of the GW localization
region
26- 28 I3 Mpc Dist [108/632] GW median distance
30- 32 I3 Mpc e_Dist [38/186] Dist uncertainty
34- 37 A4 --- Class Most probable GW classification (1)
39- 43 F5.2 % P1 [22.21/88.57]? Probablity (2)
45- 49 F5.2 % Cov1 [0.8/87] Coverage based on the BAYESTAR
sky map (3)
51- 55 F5.2 % P2 [15.76/78.37]? Probability observed
at least twice
57- 61 F5.2 % Cov2 [0.09/76.1] Coverage based on the BAYESTAR
sky map (3)
63- 68 F6.3 h Lag [0/13.73] Time lag between merger time and
the start of ZTF observations
70- 73 F4.1 mag Depth [17.9/21.5] Median depth (AB mag)
75- 78 F4.2 mag E(B-V) [0.02/0.34] Median line-of-sight extinction
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Note (1): Classification as follows:
NSBH = neutron star black hole (8 occurrences)
BNS = binary neutron star (5 occurrences)
Note (2): The integrated probability within the 90% contour of the LALInference
sky map, covered by triggered and serendipitous ZTF searches during
the first 3 days after merger observed at least once.
Note (3): For some alerts, only BAYESTAR sky maps were made available.
All estimates correct for chip gaps and processing failures.
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Byte-by-byte Description of file: table[2-9].dat table10.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name ZTF name of the source
14- 23 A10 --- OName TNS name
25- 35 F11.7 deg RAdeg [2/355.4] Rigth ascension (J2000)
37- 47 F11.7 deg DEdeg [-26.7/79.5] Declination (J2000)
49 A1 --- l_z Limit flag on z
51- 56 F6.4 --- z [0/1.3]? Host redshift
58 A1 --- n_z [sp] s=spectroscopic or p=photometric
60 A1 --- Filt [gri] Filter
62- 66 F5.2 mag mag [16.14/21.35] Discovery magnitude
68- 72 F5.2 mag e_mag [0.03/19.7] Uncertainty on the mag
74-100 A27 --- Rej Rejection criteria
102 A1 --- f_Rej [d] Flag on Rej (only for Table 9) (1)
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Note (1):
d = The candidates for which photometric evolution has been calculated
with a baseline (Δt) between 2 and 3days.
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Byte-by-byte Description of file: table1[1-8].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name ZTF name of the source
14- 22 A9 --- OName TNS name
24- 35 F12.4 d JD Julian date of observation
37- 43 A7 --- Tel Telescope (1)
45- 46 A2 --- Filt [vbugrizw1m2 ] Filter
48- 52 F5.2 mag mag [17.29/24]?=99 AB magnitude
54- 58 F5.2 mag e_mag [0.01/0.6]?=99 Uncertainty on the mag
60- 64 F5.2 mag Lim [17.2/26]?=99 Limit magnitude
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Note (1): Telescope as follows:
LT = Liverpool Telescope (64 occurrences)
GIT = GROWTH-India telescope (39 occurrences)
LOT = Lulin One-meter Telescope (27 occurrences)
UVOT = Swift/UVOT (18 occurrences)
P60 = Palomar 60 inch telescope (7 occurrences)
WHT = William Herschel Telesope at the Roque de los Muchachos Observatory
in La Palma (4 occurrences)
LCO2m = Las Cumbres Observatory 2m telescope (4 occurrences)
LCOGT1m = Las Cumbres Observatory Global Telescope 1m (3 occurrences)
APO = Apache Point Observatory (3 occurrences)
Keck1 = the Keck I telescope (2 occurrences)
LDT = Lowell Discovery Telescope (2 occurrences)
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 29-Jul-2022