J/ApJ/923/258 Gravity Collective: counterpart to GrW190814 (Kilpatrick+, 2021)
The Gravity Collective: a search for the electromagnetic counterpart to the
neutron star-black hole merger GW190814.
Kilpatrick C.D., Coulter D.A., Arcavi I., Brink T.G., Dimitriadis G.,
Filippenko A.V., Foley R.J., Howell D.A., Jones D.O., Kasen D., Makler M.,
Piro A.L., Rojas-Bravo C., Sand D.J., Swift J.J., Tucker D., Zheng W.,
Allam S.S., Annis J.T., Antilen J., Bachmann T.G., Bloom J.S., Bom C.R.,
Bostroem K.A., Brout D., Burke J., Butler R.E., Butner M., Campillay A.,
Clever K.E., Conselice C.J., Cooke J., Dage K.C., de Carvalho R.R.,
de Jaeger T., Desai S., Garcia A., Garcia-Bellido J., Gill M.S.S.,
Girish N., Hallakoun N., Herner K., Hiramatsu D., Holz D.E., Huber G.,
Kawash A.M., McCully C., Medallon S.A., Metzger B.D., Modak S., Morgan R.,
Munoz R.R., Munoz-Elgueta N., Murakami Y.S., F.O. E, Palmese A.,
Patra K.C., Pereira M.E.S., Pessi T.L., Pineda-Garcia J.,
Quirola-Vasquez J., Ramirez-Ruiz E., Rembold S.B., Rest A., Rodriguez O.,
Santana-Silva L., Sherman N.F., Siebert M.R., Smith C., Smith J.A.,
Soares-Santos M., Stacey H., Stahl B.E., Strader J., Strasburger E.,
Sunseri J., Tinyanont S., Tucker B.E., Ulloa N., Valenti S.,
Vasylyev S.S., Wiesner M.P., Zhang K.D.
<Astrophys. J., 923, 258 (2021)>
=2021ApJ...923..258K 2021ApJ...923..258K
ADC_Keywords: Gravitational wave; Stars, neutron; Black holes; Redshifts;
Spectra, optical; Photometry, ugriz
Keywords: Gravitational waves ; Neutron stars ; Black holes
Abstract:
We present optical follow-up imaging obtained with the Katzman
Automatic Imaging Telescope, Las Cumbres Observatory Global Telescope
Network, Nickel Telescope, Swope Telescope, and Thacher Telescope of
the LIGO/Virgo gravitational wave (GW) signal from the neutron
star-black hole (NSBH) merger GW190814. We searched the GW190814
localization region (19deg2 for the 90th percentile best
localization), covering a total of 51deg2 and 94.6% of the
two-dimensional localization region. Analyzing the properties of
189 transients that we consider as candidate counterparts to the NSBH
merger, including their localizations, discovery times from merger,
optical spectra, likely host galaxy redshifts, and photometric
evolution, we conclude that none of these objects are likely to be
associated with GW190814. Based on this finding, we consider the
likely optical properties of an electromagnetic counterpart to
GW190814, including possible kilonovae and short gamma-ray burst
afterglows. Using the joint limits from our follow-up imaging, we
conclude that a counterpart with an r-band decline rate of
0.68mag/day, similar to the kilonova AT 2017gfo, could peak at an
absolute magnitude of at most -17.8mag (50% confidence). Our data are
not constraining for "red" kilonovae and rule out "blue" kilonovae
with M>0.5M☉ (30% confidence). We strongly rule out all known
types of short gamma-ray burst afterglows with viewing angles <17°
assuming an initial jet opening angle of ∼5.2 and explosion energies
and circumburst densities similar to afterglows explored in the
literature. Finally, we explore the possibility that GW190814 merged
in the disk of an active galactic nucleus, of which we find four in
the localization region, but we do not find any candidate counterparts
among these sources.
Description:
The 1M2H collaboration coordinated follow-up observations between
three 0.7-1m telescopes in order to search for optical counterparts
to GW190814. In addition, we coordinated observations with KAIT and 1m
telescopes in the Las Cumbres Network, all of which targeted galaxies
in the localization region of GW190814. Finally, we observed eight
galaxies and two counterparts in the localization region of GW190814
with Keck/MOSFIRE, although we were unable to obtain later follow-up
imaging using the same instrument and filters.
The 0.76m Katzman Automatic Imaging Telescope (KAIT) at Lick
Observatory targeted galaxies in the localization region of GW190814
on 2019 August 15 and 18. See Section 2.1.1.
We targeted 10 fields in a single epoch of target-of-opportunity
imaging with the Multi-Object Spectrometer for Infra-Red Exploration
(MOSFIRE) on the Keck I 10m telescope on 2019 August 15.
See Section 2.1.2.
We also observed the localization region of GW190814 with the Las
Cumbres Observatory global network, specifically with its 1m
telescopes at the McDonald Observatory in Texas, the Cerro Tololo
Inter-American Observatory in Chile, the Siding Spring Observatory in
Australia, and the South African Astronomical Observatory.
See Section 2.1.3.
We used the Nickel 1m telescope at Lick Observatory, Mt. Hamilton,
California, to observe galaxies in the localization region of GW190814
on 2019 August 14-19, 22, 27, and 30, as well as on 2019 September 3
and 11. See Section 2.1.4.
We observed the localization region of GW190814 with the Swope 1m
telescope at Las Campanas Observatory, Chile, from 2019 August 14 to
September 10. See Section 2.1.5.
The Thacher 0.7m telescope is a robotic telescope located at the
Thacher School Observatory in Ojai, California. We observed the
localization region of GW190814 from 2019 August 15 to September 2
with 180s r-band exposures. See Section 2.1.6.
We obtained spectra of candidate EM counterparts to GW190814 and
potential host galaxies with Keck, the Shane 3m telescope at Lick
Observatory, and the SOAR 4m telescope on Cerro Pachon, Chile.
Our Keck, Shane, and SOAR spectra of GW190814 candidate counterparts
were obtained from 2019 August 17 to September 1.
See Sections 2.2 and 3.2.
We obtained a spectrum of the GW190814 counterpart candidate AT2019osy
on 2019 August 28 using the DEep Imaging Multi-Object Spectrograph
(DEIMOS) on the Keck II 10m telescope. See Section 2.3.
We used Keck/MOSFIRE to observe the candidate counterpart to GW190814
AT2019nrm on 2019 August 18. See Section 2.3.1.
We observed candidate EM counterparts and host galaxies with the Kast
double spectrograph on the Shane 3m telescope on 2019 August 26 and
31, September 2, 5, and 21, and October 8. See Section 2.3.2.
We used the Goodman spectrograph on the Southern Astrophysical
Research (SOAR) 4m telescope to observe candidate EM counterparts and
host galaxies of GW190814 on 2019 August 17 and September 1.
See Section 2.3.3.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 48 2598 Optical/IR imaging of the GW190814 localization
region
table2.dat 127 189 Candidate electromagnetic counterparts to GW190814
table3.dat 99 45 *Spectra of candidates and host galaxies
table4.dat 34 76 Photometry of candidate electromagnetic counterparts
to GW190814
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Note on table3.dat: Our Keck/DEIMOS, Keck/MOSFIRE, Shane/Kast, and SOAR/Goodman
spectra are described in Section 2.2.
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See also:
II/183 : UBVRI Photometric Standards (Landolt 1992)
VII/259 : 6dF galaxy survey final redshift release (Jones+, 2009)
VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010)
II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016)
II/357 : The Dark Energy Survey (DES): Data Release 1 (Abbott+, 2018)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
VII/281 : GLADE v2.3 catalog (Dalya+, 2018)
VII/292 : DESI Legacy Imaging Surveys DR8 (Duncan, 2022)
J/AJ/130/873 : BQS objects in the SDSS DR3 area (Jester+, 2005)
J/AJ/130/2012 : Redshifts in SARS clusters (Way+, 2005)
J/ApJS/190/418 : Light curves for 165 SNe (Ganeshalingam+, 2010)
J/ApJ/743/34 : WISE and SDSS-DR7 data in 69 galaxy clusters (Chung+, 2011)
J/MNRAS/425/1819 : Berkeley supernova Ia program. II. (Silverman+, 2012)
J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)
J/ApJS/221/12 : AGNs in the MIR using AllWISE data (Secrest+, 2015)
J/MNRAS/459/3939 : Type II supernova light curves (Valenti+, 2016)
J/ApJ/848/L33 : Opt. follow-up of GW events with LCO (Arcavi+, 2017)
J/ApJ/884/L55 : Opt. follow-up within S190814bv region (Gomez+, 2019)
J/A+A/643/A113 : iz photometry of S190814bv ctp candidates (Ackley+, 2020)
J/ApJ/890/131 : Follow-up of counterparts of S190814bv (Andreoni+, 2020)
J/A+A/649/A72 : GW190814 observations taken with MeerLICHT (de Wet+, 2021)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- Tel Survey source identifier (G1)
3- 4 I2 h RAh Hour of Right Ascension (J2000)
6- 7 I2 min RAm Minute of Right Ascension (J2000)
9- 14 F6.3 s RAs Second of Right Ascension (J2000)
16 A1 --- DE- Sign of the Declination (J2000)
17- 18 I2 deg DEd Degree of Declination (J2000)
20- 21 I2 arcmin DEm Arcminute of Declination (J2000)
23- 28 F6.3 arcsec DEs Arcsecond of Declination (J2000)
30- 39 F10.4 d MJD [58709.9/58737.6] Modified Julian Date
41 A1 --- Filt Filter (C, J, g, r or i)
43- 48 F6.2 mag maglim [11.5/22.5]? AB magnitude limit in Filter (2)
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Note (2): In-band 3σ limit for the reported image as described in
Section 2 and Section 4. The "Clear" filter is abbreviated as "C"
for all KAIT observations. All magnitudes are on the AB system.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Name Candidate counterpart
10- 11 I2 h RAh Hour of Right Ascension (J2000)
13- 14 I2 min RAm Minute of Right Ascension (J2000)
16- 21 F6.3 s RAs Second of Right Ascension (J2000)
23- 23 A1 --- DE- Sign of the Declination (J2000)
24- 25 I2 deg DEd Degree of Declination (J2000)
27- 28 I2 arcmin DEm Arcminute of Declination (J2000)
30- 34 F5.2 arcsec DEs Arcsecond of Declination (J2000)
36- 41 F6.4 --- Prob [0.1/1] Cumulative LVC probability (1)
43- 53 F11.5 d MJD [58710.2/58723.5] Modified Julian Discovery Date
55- 61 F7.5 --- z [0.0008/0.5]? Redshift
63- 69 F7.5 --- e_z [0/0.4]? Uncertainty in z
71- 74 A4 --- n_z Reference for z (2)
76- 76 A1 --- Filt [riz] Filter
78- 83 F6.2 mag Mag [-25/-6]? Absolute AB magnitude in Filter (3)
85- 88 F4.2 mag e_Mag [0.1/0.5]? Uncertainty in Mag
90- 93 F4.1 d Days [0.4/13.5]? Observer-frame days (4)
95- 98 A4 --- Rej Rejection reason (5)
100-125 A26 --- Note Additional notes (6)
127 A1 --- n_Name Flag on Name (7)
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Note (1): Within the GW190814_skymap map provided by
Abbott+ (2020PhRvL.125j1102A 2020PhRvL.125j1102A).
Note (2): Redshifts are identified as spectroscopic ("s"; 51 occurrences) or
photometric (by source) as described in Section 3.
Note (3): At the earliest detection epoch.
Note (4): Relative to GW 190814 merger.
Note (5): We rule out each source based on likely classification.
Code as follows:
MP = minor planets (11 occurrences),
SN = supernovae (12 occurrences),
VAR = pre-merger variability (2 occurrences),
Z = a redshift inconsistent with the GW190814 volume (135 occurrences),
PHOT = photometric evolution (29 occurrences)
See Section 3.
Note (6): For minor planets we give the identified minor planet, and
for supernovae we give the type described in Section 3.2.
Note (7): Flag as follows:
e = The photometry used to rule out 2019qbz is presented in
Ackley+ (2020, J/A+A/643/A113). 2019qbz has a relatively
flat light curve across ∼6d of follow up as shown
in Figure 5.
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Name Name of the source
9 A1 --- f_Name Flag on Name (1)
11- 20 A10 "Y/M/D" Date Date of observation (UTC)
22- 36 A15 --- Tel Telescope
38- 43 A6 --- Type Spectral types for transient spectra
45- 50 F6.4 --- z [0.01/1.8]? Spectroscopic redshift
52- 57 F6.4 --- e_z [0.0001/0.005]? z uncertainty
59 A1 --- f_z Flag on z (1)
61- 65 F5.3 --- zphPS1 [0.002/0.4]? PS1-STRM (Beck+ 2021MNRAS.500.1633B 2021MNRAS.500.1633B)
photometric redshift
67- 71 F5.3 --- e_zphPS1 [0.004/0.3]? zphPS1 uncertainty
73- 77 F5.3 --- zphL [0.018/0.4]? Legacy (Zhou+ 2021MNRAS.501.3309Z 2021MNRAS.501.3309Z)
photometric redshift
79- 83 F5.3 --- e_zphL [0.007/0.4]? zphL uncertainty
85- 99 A15 --- Ref Reference(s) relevant to the discovery and
classification of each candidate (2)
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Note (1): Flag as follows:
b = Spectra of these objects are not presented in this publication, but
their classifications and redshifts are used in our analysis and can be
found in the references given.
a = Spectra did not meet our cross-correlation height-to-noise ratio (r)
threshold r>4. See discussion in Section 3.4.
Note (2): References as follows:
1 = Ackley et al. (2020A&A...643A.113A 2020A&A...643A.113A)
2 = Andreoni & Goldstein (Transient Name Server Discovery Report,2019-1496 ;
2019TNSTR1804....1A 2019TNSTR1804....1A)
3 = Gomez et al. (2019TNSCR2270....1G 2019TNSCR2270....1G)
4 = Andreoni et al. (2020ApJ...890..131A 2020ApJ...890..131A)
5 = Andreoni & Goldstein (Transient Name Server Discovery Report,2019-1507 ;
2019TNSTR1804....1A 2019TNSTR1804....1A)
6 = Tucker et al. (2019GCN.25484....1T 2019GCN.25484....1T)
7 = Buckley et al. (2019TNSCR1595....1B 2019TNSCR1595....1B)
8 = Herner (2019TNSTR1497....1H 2019TNSTR1497....1H)
9 = Al (Transient Name Server Discovery Report,2019-1509;
2019TNSTR1455....1A 2019TNSTR1455....1A)
10 = Hiramatsu et al. (2019TNSCR.738....1H 2019TNSCR.738....1H)
11 = Morgan et al. (2020ApJ...901...83M 2020ApJ...901...83M)
12 = Andreoni & Goldstein (Transient Name Server Discovery Report,2019-1516 ;
2019TNSTR1804....1A 2019TNSTR1804....1A)
13 = Dimitriadis et al. (2019GCN.25395....1D 2019GCN.25395....1D)
14 = Herner & Team (Transient Name Server Discovery Report,2019-1526 ;
2019TNSTR1497....1H 2019TNSTR1497....1H)
15 = Soares-Santos et al. (2019ApJ...876L...7S 2019ApJ...876L...7S)
16 = Andreoni & Goldstein (Transient Name Server Discovery Report,2019-1525 ;
2019TNSTR1804....1A 2019TNSTR1804....1A)
17 = Wiesner et al. (2019GCN.25596....1W 2019GCN.25596....1W)
18 = Wiesner et al. (2019GCN.25540....1W 2019GCN.25540....1W)
19 = Dobie et al. (2019GCN.25445....1D 2019GCN.25445....1D)
20 = Al (Transient Name Server Discovery Report,2019-1536;
2019TNSTR1455....1A 2019TNSTR1455....1A)
21 = Andreoni & Goldstein (Transient Name Server Discovery Report,2019-1562;
2019TNSTR1804....1A 2019TNSTR1804....1A)
22 = Al (Transient Name Server Discovery Report,2019-1563;
2019TNSTR1455....1A 2019TNSTR1455....1A)
23 = Castro-Tirado et al. (2019GCN.25543....1C 2019GCN.25543....1C)
24 = Herner (Transient Name Server Discovery Report,2019-1579;
2019TNSTR1497....1H 2019TNSTR1497....1H)
25 = Chambers et al. (2019TNSTR...5....1C 2019TNSTR...5....1C)
26 = Al (Transient Name Server Discovery Report,2019-1604;
2019TNSTR1455....1A 2019TNSTR1455....1A)
27 = Al (Transient Name Server Discovery Report,2019-1615;
2019TNSTR1455....1A 2019TNSTR1455....1A)
28 = Japelj et al. (2019GCN.25526....1J 2019GCN.25526....1J)
29 = Jaodand et al. (2019GCN.25822....1J 2019GCN.25822....1J)
30 = Bauer et al. (2019GCN.25801....1B 2019GCN.25801....1B)
31 = Stewart et al. (2019GCN.25487....1S 2019GCN.25487....1S)
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Name Candidate counterpart
10- 19 F10.4 d MJD [58710.2/58737.4] Modified Julian Date
21 A1 --- Filt [r] Filter
23- 27 F5.2 mag mag [17.42/21.68] Apparent magnitude in Filter (1)
29- 32 F4.2 mag e_mag [0.02/0.4] Uncertainty in mag
34 A1 --- Tel Survey source identifier (G1)
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Note (1): All photometry of candidate counterparts (Table 5) to GW190814 from
follow up and search observations presented in this paper. We use
these data along with photometry presented in
Andreoni+ (2020, J/ApJ/890/131), Ackley+ (2020, J/A+A/643/A113), and
Morgan+ (2020ApJ...901...83M 2020ApJ...901...83M) to classify all candidates.
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Global notes:
Note (G1): Source as follows:
K = The 0.76m Katzman Automatic Imaging Telescope (KAIT), California
M = Keck/MOSFIRE;
L = Las Cumbres Observatory;
N = Nickel 1m telescope, California
S = Swope 1m telescope, Chile
T = Thacher 0.7m telescope, California
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 02-Jun-2023