J/A+A/667/A4 NGC4631 luminous red nova AT 2021biy light curves (Cai+, 2022)
Forbidden hugs in pandemic times. III.
Observations of the luminous red nova AT 2021biy in the nearby galaxy NGC 4631.
Cai Y-Z., Pastorello A., Fraser M., Wang X.-F., Filippenko A.V.,
Reguitti A., Patra K.C., Goranskij V.P., Barsukova E.A., Brink T.G.,
Elias-Rosa N., Stevance H.F., Zheng W., Yang Y., Atapin K.E., Benetti S.,
de Boer T.J.L., Bose S., Burke J., Byrne R., Cappellaro E., Chambers K.C.,
Chen W.-L., Emami N., Gao H., Hiramatsu D., Howell D.A., Huber M.E.,
Kankare E., Kelly P.L., Kotak R., Kravtsov T., Lander V.Yu., Li Z.-T.,
Lin C.-C., Lundqvist P., Magnier E.A., Malygin E.A., Maslennikova N.A.,
Matilainen K., Mazzali P.A., McCully C., Mo J., Moran S., Newsome M.,
Oparin D.V., Padilla Gonzalez E., Reynolds T.M., Shatsky N.I., Smartt S.J.,
Smith K.W., Stritzinger M.D., Tatarnikov A.M., Terreran G., Uklein R.I.,
Valerin G., Vallely P.J., Vozyakova O.V., Wainscoat R., Yan S.-Y.,
Zhang J.-J., Zhang T.-M., Zheltoukhov S.G., Dastidar R., Fulton M.,
Galbany L., Gangopadhyay A., Ge H.-W., Gutierrez C.P., Lin H., Misra K.,
Ou Z.-W., Salmaso I., Tartaglia L., Xiao L., Zhang X.-H.
<Astron. Astrophys. 667, A4 (2022)>
=2022A&A...667A...4C 2022A&A...667A...4C (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Galaxies, nearby ; Photometry, SDSS ;
Photometry, infrared ; Photometry, UBVRI
Keywords: binaries: close - stars: winds, outflows -
stars: individual: AT 2021biy
Abstract:
We present an observational study of the luminous red nova (LRN) AT
2021biy in the nearby galaxy NGC 4631. The field of the object was
routinely imaged during the pre-eruptive stage by synoptic surveys,
but the transient was detected only at a few epochs from ∼231 days
before maximum brightness. The LRN outburst was monitored with
unprecedented cadence both photometrically and spectroscopically. AT
2021biy shows a short-duration blue peak, with a bolometric luminosity
of ∼1.6x1041erg/s, followed by the longest plateau among LRNe to
date, with a duration of 210 days. A late-time hump in the light curve
was also observed, possibly produced by a shell-shell collision. AT
2021biy exhibits the typical spectral evolution of LRNe. Early-time
spectra are characterised by a blue continuum and prominent H emission
lines. Then, the continuum becomes redder, resembling that of a K-type
star with a forest of metal absorption lines during the plateau phase.
Finally, late-time spectra show a very red continuum (TBB~=2050K) with
molecular features (e.g., TiO) resembling those of M-type stars.
Spectropolarimetric analysis indicates that AT 2021biy has local dust
properties similar to those of V838 Mon in the Milky Way Galaxy.
Inspection of archival Hubble Space Telescope data taken on 2003
August 3 reveals a ∼20M☉ progenitor candidate with
log(L/L☉)=5.0dex and Teff=5900K at solar metallicity. The above
luminosity and colour match those of a luminous yellow supergiant.
Most likely, this source is a close binary, with a 17-24M☉
primary component.
Description:
Photometry tables for the luminous red nova AT 2021biy.
Follow-up images in the Johnson-Cousins UBV, Sloan ugriz, and NIR JHK
filters were obtained using a number of facilities available to our
collaboration. Their setups are summarised as follows: The Las Cumbres
Observatory (LCO) global telescopes located at different sites:
firstly, ELP (two 1m telescopes) at McDonald Observatory, Texas, USA.
secondly, TFN (two 0.4m telescopes and one 1m telescope) at Teide
Observatory, Tenerife, Spain; The 0.8m Tsinghua-NAOC Telescope (TNT)
at Xinglong Observatory, China; The 0.67m/0.92m Schmidt telescope
with a Moravian camera at Padova Astronomical Observatory, Istituto
Nazionale di Astrofisica (INAF), Asiago, Italy; The 1m Zeiss
telescope of the Special Astrophysical Observatory (SAO), Russian
Academy of Sciences (RAS), Russia; The 1.82m Copernico Telescope with
the Asiago Faint Object Spectrograph and Camera (AFOSC), hosted by
INAF - Padova Astronomical Observatory, at the Asiago site, Italy;
The 2.0m Liverpool telescope (LT) equipped with the IO:O camera,
located at Observatorio Roque de Los Muchachos, La Palma, Spain; The
2.56m Nordic Optical Telescope (NOT), at Observatorio Roque de Los
Muchachos, La Palma, Spain, with the Alhambra Faint Object
Spectrograph and Camera (ALFOSC) and the Nordic Optical Telescope
near-infrared Camera (NOTCam); The 2.5m Caucasus telescope with the
IR camera ASTRONIRCAM, hosted by the Caucasian Observatory of the
Sternberg Astronomical Institute (SAI) of Lomonosov Moscow State
University; The 3.5m telescope with the Omega-2000 NIR imager at the
Calar Alto Observatory, Spain; The 6m telescope (BTA - Big Telescope
Alt-azimuth) equipped with the SCORPIO-1 and SCORPIO-2 instruments,
located near Mt. Pastukhova of the Special Astrophysical Observatory,
Russia; The 10.4m Gran Telescopio Canarias (GTC), at Observatorio
Roque de Los Muchachos, La Palma, Spain, with the Espectrografo
Multiobjeto Infra-Rojo (EMIR) instrument; One epoch of mid-infrared
(MIR) photometry in the W1 and W2 filters was obtained by the
Wide-field Infrared Survey Explorer (WISE) spacecraft.
Objects:
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RA (2000) DE Designation(s)
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12 42 04.02 +32 32 07.9 AT 2021biy = ATLAS 21dfy
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 46 63 Johnson-Cousins B band light curve of AT 2021biy
tablea2.dat 46 91 Johnson-Cousins V band light curve of AT 2021biy
tablea3.dat 49 9 Sloan u band light curve of AT 2021biy
tablea4.dat 47 78 Sloan g band light curve of AT 2021biy
tablea5.dat 47 105 Sloan r band light curve of AT 2021biy
tablea6.dat 46 110 Sloan i band light curve of AT 2021biy
tablea7.dat 44 50 Sloan z band light curve of AT 2021biy
tablea8.dat 36 131 ATLAS cyan band light curve of AT 2021biy
tablea9.dat 36 407 ATLAS orange band light curve of AT 2021biy
tablea10.dat 37 12 Pan-STARRS i band light curve of AT 2021biy
tablea11.dat 37 42 Pan-STARRS z band light curve of AT 2021biy
tablea12.dat 37 10 Pan-STARRS y band light curve of AT 2021biy
tablea13.dat 85 42 *Near-infrared (NIR) YJHK light curves of AT 2021biy
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Note on tablea13.dat: We also provide the WISE photometry at
MJD = 59359.9 (+108.9 days): W1 = 14.38 (0.20), W2 = 14.27 (0.26) mag.
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See also:
J/A+A/646/A119 : M31 luminous red nova AT 2019zhd photometry (Pastorello+ 2021)
J/A+A/647/A93 : AT 2020hat and AT 2020kog light curves (Pastorello+, 2021)
Byte-by-byte Description of file: tablea1.dat tablea2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Date Date of observation (YYYY/MM/DD)
12- 20 F9.3 d MJD Modified Julian Date
23 A1 --- Band [BV] Band (Johnson-Cousins)
25 A1 --- l_mag Limit flag on mag
26- 31 F6.3 mag mag Johnson-Cousins magnitude in Band
33- 37 F5.3 mag e_mag ? Johnson-Cousins magnitude in Band error
39- 46 A8 --- Inst Instrument name
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Byte-by-byte Description of file: tablea[34567].dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Date Date of observation (YYYY/MM/DD)
12- 20 F9.3 d MJD Modified Julian Date
23 A1 -- Band [ugriz] Band (Sloan)
25 A1 --- l_mag Limit flag on mag
26- 31 F6.3 mag mag Sloan magnitude in Band
33- 37 F5.3 mag e_mag ? Sloan magnitude in Band error
39- 47 A9 --- Inst Instrument name
49 A1 --- Note [a] Notes (1)
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Note (1): Note as follows:
a = Johnson-Cousins U-band data were converted to Sloan u-band magnitudes,
following the relations of Jester et al. (2005AJ....130..873J 2005AJ....130..873J)
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Byte-by-byte Description of file: tablea8.dat tablea9.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Date Date of observation (YYYY/MM/DD)
12- 19 A8 d MJD Modified Julian Date
22 A1 --- Band [co] Band (ATLAS, c for cyan, o for orange)
24 A1 --- l_mag Limit flag on mag
25- 30 F6.3 mag mag ATLAS magnitude in Band
32- 36 F5.3 mag e_mag ? ATLAS magnitude in Band error
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Byte-by-byte Description of file: tablea10.dat tablea11.dat tablea12.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Date Date of observation (YYYY/MM/DD)
12- 20 F9.3 d MJD Modified Julian Date
23 A1 --- Band [izy] Band (Pan-STARRS)
25 A1 --- l_mag Limit flag on mag
26- 31 F6.3 mag mag Pan-STARRS magnitude in Band
33- 37 F5.3 mag e_mag ? Pan-STARRS magnitude in Band error
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Byte-by-byte Description of file: tablea13.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Date Date of observation (YYYY/MM/DD)
12- 20 F9.3 d MJD Modified Julian Date
22- 27 F6.1 d Phase Phase relative to r-band maximum light (1)
29- 34 F6.3 mag Ymag ?=- NIR Y band magnitude
36- 41 F6.3 mag Jmag ?=- NIR J band magnitude
43- 47 F5.3 mag e_Jmag ? NIR J band magnitude error (2)
49- 54 F6.3 mag Hmag ?=- NIR H band magnitude
56- 60 F5.3 mag e_Hmag ? NIR H band magnitude error (2)
62- 67 F6.3 mag Kmag ?=- NIR K band magnitude
69- 73 F5.3 mag e_Kmag ? NIR K band magnitude error (2)
75- 85 A11 --- Inst Instrument name
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Note (1): Phases are relative to r-band maximum light: MJD = 59251.0±1.0.
Note (2): The uncertainties in ASTRONIRCAM measurements are generally less
than 0.020mag in Y, 0.054mag in J, 0.068mag in H, and 0.086mag in K.
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Acknowledgements:
Yongzhi Cai, yzcai789(at)163.com
References:
Pastorello et al., Paper I 2021A&A...646A.119P 2021A&A...646A.119P, Cat. J/A+A/646/A119
Pastorello et al., Paper II 2021A&A...647A..93P 2021A&A...647A..93P, Cat. J/A+A/647/A93
(End) Patricia Vannier [CDS] 08-Sep-2022