J/ApJ/952/86 SN2019wxt follow-up (Shivkumar+, 2023)
SN2019wxt: an ultrastripped supernova candidate discovered in the
electromagnetic follow-up of a gravitational wave trigger.
Shivkumar H., Jaodand A.D., Balasubramanian A., Fremling C., Corsi A.,
Tzanidakis A., Nissanke S., Kasliwal M., Brightman M., Raaijmakers G.,
Madsen K.K., Harrison F., Carbone D., N. A J, Desert J.-M., Andreoni I.
<Astrophys. J., 952, 86 (2023)>
=2023ApJ...952...86S 2023ApJ...952...86S
ADC_Keywords: Transient; Spectra, optical; Photometry, ugriz; Supernovae
Keywords: Core-collapse supernovae ; Supernovae ; Ejecta ; Stellar remnants ;
Gravitational wave sources ; X-ray sources ; X-ray astronomy ;
Radio interferometry ; Extragalactic radio sources ;
Spectral line identification ; Transient detection ; Transient sources
Abstract:
We present optical, radio, and X-ray observations of a rapidly
evolving transient SN2019wxt (PS19hgw), discovered during the search
for an electromagnetic counterpart to the gravitational-wave (GW)
trigger S191213g. Although S191213g was not confirmed as a significant
GW event in the off-line analysis of LIGO-Virgo data, SN2019wxt
remained an interesting transient due to its peculiar nature. The
optical/near-infrared (NIR) light curve of SN2019wxt displayed a
double-peaked structure evolving rapidly in a manner analogous to
currently known ultrastripped supernovae (USSNe) candidates. This
double-peaked structure suggests the presence of an extended envelope
around the progenitor, best modeled with two components:
(i) early-time shock-cooling emission and (ii) late-time radioactive
56Ni decay. We constrain the ejecta mass of SN2019wxt at
Mej∼0.20M☉, which indicates a significantly stripped
progenitor that was possibly in a binary system. We also followed up
SN2019wxt with long-term Chandra and Jansky Very Large Array
observations spanning ∼260days. We detected no definitive counterparts
at the location of SN2019wxt in these long-term X-ray and radio
observational campaigns. We establish the X-ray upper limit at
9.93x10-17erg/cm2/s and detect an excess radio emission from the
region of SN2019wxt. However, there is little evidence for SN1993J- or
GW170817-like variability of the radio flux over the course of our
observations. A substantial host-galaxy contribution to the measured
radio flux is likely. The discovery and early-time peak capture of
SN2019wxt in optical/NIR observations during EMGW follow-up
observations highlight the need for dedicated early, multiband
photometric observations to identify USSNe.
Description:
SN2019wxt was discovered on 2019 December 16 UTC 07:19:12
(MJD58833.305).
The Global Relay of Observatories Watching Transients Happen (GROWTH)
collaboration conducted further follow-up observations using the
Spectral Energy Distribution Machine (SEDM) on the Palomar 60 inch
telescope (P60). The GROWTH collaboration also obtained 300s exposure
images in g, r, and i filters with the Lulin 1m Telescope (LOT)
located in Taiwan. Follow-up observations of SN2019wxt were also
conducted with the Large Monolithic Imager on the 4.3m Lowell's
Discovery Channel Telescope (DCT; located in Arizona) for each of the
griz filters. Simultaneously, optical observations of SN2019wxt were
also undertaken with the three-channel imager 3KK camera on the 2m
telescope at the Wendelstein Observatory.
The observations and photometric measurements are summarized in Table7
and span ∼20.7days since the initial detection.
Early-time spectroscopic observations of SN2019wxt were taken on
2019 December 18 and 19 (see Table 8).
In this work, we use early-time spectroscopic observations obtained
with various telescopes, such as: (i) the 2m Himalayan Chandra
Telescope (HCT) at Indian Astronomical Observatory at Hanle; (ii) the
8.2m Very Large Telescope (VLT) UT1 at European Southern Observatory
(ESO) at Paranal Observatory, Chile; (iii) the 3.58m New Technology
Telescope (NTT) at La Silla Observatory, as part of the
extended-Public ESO Spectroscopic Survey for Transient Objects
(ePESSTO; PI: Smartt); and (iv) the 8.4m Large Binocular Telescope
(LBT) at LBT Observatory in Arizona, USA.
We obtained high-resolution (∼1") X-ray imaging observations of
SN2019wxt with the Chandra X-ray. See Section 2.3.
Radio observations of the SN2019wxt field were carried out using the
Karl G. Jansky Very Large Array (VLA) between UT 2019 December 19 and
2020 August 20 in the D (VLA:19A-222; PI: Troja), C, and B
configurations (VLA:18B-320 and VLA:20A-115; PI: Frail). These
observations were performed at nominal central frequencies of 10GHz
(X band), 15GHz (Ku band), and 22GHz (K band). See Section 2.4.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
01 55 41.94 +31 25 04.5 SN2019wxt = PSST 19hgw
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table7.dat 85 44 Summary of optical observations of SN2019wxt
table8.dat 128 4 Summary of optical spectroscopic observations
of SN2019wxt
sp/* . 4 HCT-IIA telescope, VLT, NTT and LBT spectra of SN2019wxt
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See also:
J/MNRAS/383/1485 : BVRI light curves of SN 2003jd (Valenti+, 2008)
J/MNRAS/436/774 : Core collapse supernovae (type Ibc) (Eldridge+, 2013)
J/MNRAS/431/308 : SN 2011fu BVRI light curves (Kumar+, 2013)
J/A+A/561/A146 : SN 2010ae optical spectra (Stritzinger+, 2014)
J/A+A/593/A68 : PTF12os and iPTF13bvn spectra and LCs (Fremling+, 2016)
J/ApJ/848/L33 : Opt. follow-up of GW events with LCO (Arcavi+, 2017)
J/other/Sci/362.201 : iPTF 14gqr (SN 2014ft) photometry (De+, 2018)
J/ApJ/895/49 : Optical sp. of ZTF18abvkwla & its host galaxy (Ho+, 2020)
J/ApJ/898/166 : UV to NIR obs. of SN 2019ehk (Jacobson-Galan+, 2020)
J/ApJ/905/145 : ZTF cand. counterparts to GW follow-up (Kasliwal+, 2020)
J/ApJ/900/46 : UV, optical and IR light curve of SN2019dge (Yao+, 2020)
J/ApJ/918/63 : Fast-transients confirmed by ZTF & LCs (Andreoni+, 2021)
Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Inst Instrument
16- 40 A25 --- Auth Author's name for the reference
42- 60 A19 --- BibCode Bibcode of the reference
62- 70 F9.3 d MJD [58829.3/58854] Modified Julian Date of the
observation (1)
72 A1 --- Filt Filter (g,r,i,z,y or J)
74 A1 --- l_mag Limit flag on mag
76- 80 F5.2 mag mag [18.9/23.5] Magnitude
82- 85 F4.2 mag e_mag [0.01/0.22]? Uncertainty on mag
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Note (1): The observation of SN2019wxt at MJD 58833.305 sets the
reference epoch for this work.
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Byte-by-byte Description of file: table8.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.3 d MJD [58835.75/58836.22] Modified Julian Date of the
start of observation
11- 21 A11 --- Tel Telescope
23- 32 A10 --- Inst Instrument
34- 42 A9 0.1nm lambda Wavelength range in Å
44- 52 F9.4 s Exp [1200/3600] Exposure time
54- 59 A6 --- Res Resolution
61- 64 F4.2 d Phase [2.45/2.91] Phase; column added by CDS
(from Data behind Figure 8)
66-128 A63 --- File Name of the file in ASCII format
in subdirectory "sp"; column added by CDS
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 01-Sep-2025