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Spectroscopic confirmation and photometry of the first reported nova in NGC 147

ATel #11101; S. Fabrika, A. Vinokurov, Yu. Solovyeva, A. F. Valeev, D. I. Makarov (SAO RAS), K. Hornoch, H. Kucakova (Ondrejov), S. Korotkiy (Ka-Dar observatory), M. Henze (SDSU), A. W. Shafter (SDSU)
on 28 Dec 2017; 20:24 UT
Credential Certification: Sergei Fabrika (fabrika@sao.ru)

Subjects: Optical, Nova

We report optical spectroscopic confirmation of the recent nova TCP J00333837+4836022 in the Local Group dwarf spheroidal galaxy NGC 147. The nova was discovered 2017 Dec. 22.4056 UT by K. Itagaki (Yamagata, Japan). The spectral data were obtained on 2017 Dec. 22.668 UT using the Russian BTA telescope equipped with the SCORPIO spectrograph. The spectrum was taken with a resolution of 5.3 Å in the 4050 - 5810 Å range.

Photometry of the nova obtained just near the time of the BTA spectrum with the same device gave B =16.82 ± 0.05, V = 16.67 ± 0.05, Rc = 16.58 ± 0.05. Additional photometric data were obtained with the 0.65-m telescope at Ondrejov on Dec. 26.688 UT, R = 15.88 ± 0.03 and on Dec. 27.720 UT, R = 16.23 ± 0.03; and with the BTA on Dec. 26.638 UT which gave B =17.11 ± 0.06, V = 16.67 ± 0.04, Rc = 16.10 ± 0.07.

As previously reported in ATel #11087, a spectrum taken on 2017 Dec 24.82 UT with the 2-m Liverpool Telescope showed an H-alpha line with a P Cyg profile, while other lines including hydrogen and Fe II were in absorption. Our nova spectrum was taken about 6 hr after discovery, and revealed strong H-delta, H-gamma, H-beta lines with P Cyg profiles. The blue edge of the P Cyg (absorption) in these lines is approximately -1650 km/sec, while the red wing (emission) is up to about +1300 km/sec. We could not detect other lines, because the spectrum is noisy; however, some blue-shifted absorption components were detected in Fe II 5018 Å, Mg II 4481 Å, Na I 5686 Å.

Based on the spectral characteristics before maximum light, we suggest that this nova likely belongs to the Fe II class.