J/ApJ/884/L55 Opt. follow-up of galaxies within S190814bv region (Gomez+, 2019)
A galaxy-targeted search for the optical counterpart of the candidate NS-BH
merger S190814bv with Magellan.
Gomez S., Hosseinzadeh G., Cowperthwaite P.S., Villar V.A., Berger E.,
Gardner T., Alexander K.D., Blanchard P.K., Chornock R., Drout M.R.,
Eftekhari T., Fong W., Gill K., Margutti R., Nicholl M., Paterson K.,
Williams P.K.G.
<Astrophys. J., 884, L55 (2019)>
=2019ApJ...884L..55G 2019ApJ...884L..55G
ADC_Keywords: Galaxies, spectra; Redshifts; Magnitudes, absolute; Optical;
Gravitational wave
Keywords: Gravitational waves ; Neutron stars ; Astrophysical black holes ;
Observational astronomy
Abstract:
On 2019 August 14 the Laser Interferometer Gravitational Wave
Observatory (LIGO) and the Virgo gravitational wave interferometer
announced the detection of a binary merger, S190814bv, with a low
false alarm rate of about 1 in 1.6x1025yr, a distance of
267±52Mpc, a 90% (50%) localization region of about 23 (5) deg2,
and a probability of being a neutron star-black hole (NS-BH) merger of
>99%. The LIGO/Virgo Collaboration (LVC) defines NS-BH such that the
lighter binary member has a mass of <3M☉ and the more massive
one has >5M☉, and this classification is in principle consistent
with a BH-BH merger depending on the actual upper mass cutoff for
neutron stars. Additionally, the LVC designated a probability that the
merger led to matter outside the final BH remnant of <1%, suggesting
that an electromagnetic (EM) counterpart is unlikely. Here we report
our optical follow-up observations of S190814bv using the Magellan
Baade 6.5m telescope to target all 96 galaxies in the Galaxy List for
the Advanced Detector Era catalog within the 50% localization volume
(representing about 70% of the integrated luminosity within this
region). No counterpart was identified to a median 3σ limiting
magnitude of i=22.2 (Mi~-14.9mag), comparable to the brightness of
the optical counterpart of the binary neutron star merger GW170817 at
the distance of S190814bv; similarly, we can rule out an on-axis jet
typical of short GRBs. However, we cannot rule out other realistic
models, such as a kilonova with only ∼0.01M☉ of lanthanide-rich
material, or an off-axis jet with a viewing angle of
θobs≳15°.
Description:
We commenced optical follow-up observations of the NS-BH merger
candidate S190814bv with the Inamori-Magellan Areal Camera and
Spectrograph (IMACS) on the Magellan Baade 6.5m telescope at Las
Campanas Observatory in Chile on 2019 August 16 at 08:15:38 UT (35hr
post-merger) and continued until morning twilight, with our last
exposure ending at 10:30:02 UT, observing a total of 45 galaxies. On
the following night (2019 August 17) we observed from 08:08:39 to
10:27:14 UT (59-61.3hr post-merger) and imaged 51 additional galaxies.
The 96 observed galaxies comprise all galaxies from the GLADE catalog
(see VII/281) in the 50% confidence volume of S190814bv (1.8x104Mpc3)
with luminosities of ≳0.15L*.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 104 97 Log of Magellan follow-up observations
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See also:
VII/281 : GLADE v2.3 catalog (Dalya+, 2018)
J/ApJ/848/L16 : Counterpart of GW170817. I. DECam obs. (Soares-Santos+, 2017)
J/ApJ/848/L29 : Opt. follow-up of GW170817 counterpart (Diaz+, 2017)
J/ApJ/851/L21 : UV-NIR obs. compilation of GW170817 counterpart (Villar+, 2017)
J/PASJ/70/28 : Subaru HSC counterpart candidates of GW170817 (Tominaga+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 23 A23 --- Name Name of the galaxy
25 A1 --- f_Name b: GCN circular 25382 accidentally omitted
this galaxy
27- 28 I2 h RAh Hour of right ascension (J2000)
30- 31 I2 min RAm Minute of right ascension (J2000)
33- 37 F5.2 s RAs Second of right ascension (J2000)
39 A1 --- DE- Sign of declination (J2000)
40- 41 I2 deg DEd Degree of declination (J2000)
43- 44 I2 arcmin DEm Arcminute of declination (J2000)
46- 49 F4.1 arcsec DEs Arcsecond of declination (J2000)
51- 61 A11 "Y/M/D" obs.date UT date of the observation
63- 72 A10 "h:m:s" obs.time UT time of the observation
74- 84 F11.5 d MJD [58711.3/58712.5] Modified Julian Date
86- 91 F6.4 --- z [0.026/0.074] Redshift
93- 98 F6.2 mag BMag [-22.02/-18.53] Absolute B band magnitude
100- 104 F5.2 mag Lim [19.39/22.54] Limiting magnitude
corrected for Milky Way extinction
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 30-Mar-2021