OPD-LNA photometry and spectroscopy classification of TCP J17525020-2024150 Nova Event
ATel #16143; Leandro de Almeida (LNA/MCTI), Laerte Andrade (LNA/MCTI), Felipe Navarete (NOIRLab/SOAR Telescope), Micheli Moura (UFRGS), Gabriel Hickel (UNIFEI), Danilo F. da Rocha (ON), Rubens E. G. Machado (UTFPR), Andressa Wille (UTFPR), Elvis A. M.T dos Santos (UTFPR), Giovanni Tauil (UTFPR), Gustavo F. Gonçalves (UTFPR), Nicholas S. Souza (UTFPR), Richards P. Albuquerque (UTFPR), Vinicius Freire Fochesatto (UTFPR)
on 20 Jul 2023; 00:46 UT
Credential Certification: Felipe Navarete (navarete@usp.br)
Referred to by ATel #: 16157
We confirm the Nova object in Sgr, designation: TCP J17525020-2024150, first reported by Andrew Pearce on 2023 Jul 15.459 from (CBET 5278). We performed the photometric and spectroscopic analysis of the object observed from Observatorio Pico dos Dias (OPD-LNA-MCTI) - Brazil, at 2023 Jul 16.0-16.2 UTC. The photometry analysis and imaging were obtained using two telescopes: the 0.6m Boller & Chivens telescope along a CCD Andor IKon 14912, FOV: 11.6 arcmin (2023 Jul 16.0121), and the 0.6m Zeiss telescope also with a CCD Andor IKon L13740, FOV: 12.629 arcmin (2023 Jul 16.0497).
Observations were carried out using the Bessell B, V, R, and I filters, and PSF-fitting photometry was carried out to avoid contamination from nearby stars. The instrumental magnitudes were calibrated to the Vega system using reference sources in the same FOV, and their uncertainties represent the statistical errors associated with the measurements and the calibration procedure. The magnitudes obtained with the 0.6m Boller & Chivens and the corresponding color indices are:
Filter Magnitude error MJD
Bessel (mag) (mag) (days)
B 12.99 0.08 60141.01206
V 11.01 0.10 60141.00832
R 10.79 0.07 60141.00257
B-V 1.98 0.13
B-R 2.20 0.11
V-R 0.22 0.12
Aiming to further confirm the magnitudes, we also obtained the BVRI magnitudes using the 0.6m Zeiss telescope:
Filter Magnitude error MJD
Bessel (mag) (mag) (days)
B 12.92 0.30 60141.03393
V 11.05 0.13 60141.04969
R 10.76 0.30 60141.02543
I 8.46 0.05 60141.02967
B-V 1.87 0.33
B-R 2.16 0.42
B-I 4.46 0.30
V-R 0.29 0.33
V-I 2.59 0.14
R-I 2.30 0.30
The analysis of the light curve obtained at the R-band (MJD0=60140.9986808) shows a brightness decrease of 0.18 magnitude in a span of 5 hours (See R-band light-curve).
Additionally, we perform a spectroscopic analysis obtained from the Perkin-Elmer 1.60\,m telescope. Two spectra were obtained on 2023 Jul 16.0639 and 16.0882 with exposure times of 1800 sec with the Coude spectrograph (reflective holographic 600-grating, Ikon-L936-BV CCD and a 1" slit) at a resolution of about 9000 (6370-6870A, SNR $\sim$ 50) with exposure times of 1800 sec, respectively. There is no difference between them, and both show a prominent, complex, and very wide H-alpha line. A blue-shifted component in absorption at 6472.9 A suggest a P-Cygni profile but also seems to match with a telluric water absorption band. An ISM diffuse interstellar band (DIB) in absorption is observed in the red wing of H-alpha, at 6614.0A (FWHM 1.7A). The H-alpha line peaks around 6562.5 A, and the emission width extends between 6465A and 6660A, resulting in an expansion velocity of approx. 4465 km/s. Following Hachisu & Kato (2016, ApJS 223, 21), we estimated E(B-V) = 1.82 +/- 0.34 mag.
The measured coordinates of the source are RA = 17:52:49.32, Dec = -20:24:15.45 (J2000), consistent with the initial coordinates reported by (CBET 5278). The position is also consistent with the Gaia DR3 4118800145787192064 [G = 18.88+/-0.01 mag, BP-RP = 2.22+/-0.07 mag, d=531(+474,-629) pc], the likely progenitor of the event, with V=19.3+/-0.5 mag. These data allow estimates for visual extinction, absolute magnitude and distance: Av=5.6+/-1.0 (Rv=3.1), V0=-8.3+/-0.5 mag, and d~560 pc.
R-band light-curve
