Discovery, photometry and spectroscopic confirmation of AT 2022ouu (PNV J00423928+4115169) as nova in M31
ATel #15569; Filipp Romanov (amateur astronomer, Russia)
on 23 Aug 2022; 10:28 UT
Credential Certification: Kirill Sokolovsky (kirx@scan.sai.msu.ru)
Subjects: Optical, Nova, Transient
On 2022-07-14.2122 UTC I discovered an apparent nova in M31 at 3x300s Luminance images obtained at my request remotely with 0.61-m telescope of Burke-Gaffney Observatory (BGO) in Canada (Lane, 2018, RTSRE, 1, 119); it was designated AT 2022ouu = PNV J00423928+4115169 (CBAT TOCP). The latest BGO image with no object visible was obtained on 2022-07-10.2038.
AT 2022ouu was also detected by K. Hornoch and H. Kucakova (ATel #15516), K. Itagaki (CBAT TOCP), G. Goranov et al. (ATel #15520), and is present in the H-alpha image from ATel #15537 (A. Valcheva et al.).
I remotely observed AT 2022ouu from 2022 July 14 to August 4. I used the BGO telescope, 0.355-m telescope of Abbey Ridge Observatory (ARO) in Canada, 0.5-m reflector (T11) and 0.43-m reflector (T21) of iTelescope.Net in the USA, IO:O camera (Barnsley et al., 2016, JATIS, 2, 015002) and camera of the SPRAT (Piascik et al., 2014, SPIE, 9147E, 8H) on the 2-m Liverpool Telescope (Steele et al., 2004, SPIE, 5489, 679). The comparison stars magnitudes were taken from the VizieR catalogue J/AJ/152/62 (Massey et al. 2016) and Pan-STARRS DR1 (Chambers et al. 2016). Measured magnitudes (aperture photometry, no background subtraction):
JD / Mag. / Instrument / Exposure
CV magnitudes (using Luminance filter, V zero point):
2459774.71597 17.96 BGO 3x300s
2459794.71806 17.98 BGO 2x300s
CV magnitudes (unfiltered with V zero point):
2459778.71395 17.26 SPRAT 3x10s
2459779.64144 17.35 SPRAT 3x10s
2459795.65271 17.90 SPRAT 5x10s
Sloan r':
2459779.64608 17.12 IO:O 60s
Johnson V:
2459776.77431 17.42 ARO 300s
2459776.91319 17.30 T11 2x300s
2459777.90694 17.36 T21 2x300s
2459778.69653 17.30 BGO 6x300s
2459780.71042 17.16 BGO 6x300s
2459781.69792 17.31 BGO 6x300s
2459783.67014 17.86 BGO 6x300s
2459784.69306 17.28 BGO 6x300s
2459788.71806 17.74 BGO 6x300s
2459789.73750 18.06 BGO 5x300s
Cousins Rc:
2459776.92083 17.13 T11 2x300s
2459776.94167 16.94 T11 300s
2459777.71667 16.84 BGO 4x300s
2459777.92222 16.81 T21 2x300s
2459778.76944 16.97 BGO 6x300s
2459780.73472 17.05 BGO 3x300s
2459781.72222 17.08 BGO 6x300s
2459783.74653 17.52 BGO 6x300s
2459784.72083 17.03 BGO 6x300s
2459788.74167 17.39 BGO 6x300s
Johnson B:
2459777.91319 17.90 T21 2x300s
2459778.72014 17.95 BGO 6x300s
2459780.75833 17.71 BGO 6x300s
2459781.74653 17.81 BGO 6x300s
Magnitude errors are between 0.05-0.1 mag. for the LT images and 0.2-0.3 mag. for others. The peak absolute magnitude of AT 2022ouu is M ~ -7.22; combined light curve.
The measured nova position 00:42:39.28 +41:15:16.7 (J2000) is close to PNV J00423895+4115171 = M31N 2017-08a (ATel #10618; spectra available in the LT Data Archive), but when comparing the discovery images, the objects do not match.
The low resolution (R ~ 350) spectrum of AT 2022ouu was obtained with SPRAT spectrograph at the Liverpool Telescope on 2022-08-04.1653 (1800s exposure; PATAG proposal AZ22A01; PI: F. Romanov); reduced by Andrea Pastorello (INAF-OAPd), calibrated and analyzed by me. It shows strong emission lines: H-alpha, H-beta, Fe II (42, 48, 49 multiplets) and Na I D (or He 5876); Fe II lines are as strong as H-beta. I measured the FWHM of the H-alpha line ~34 Angstroms, corresponding to the velocity of ~1550 km/s. Based on the above, I conclude that AT 2022ouu is a Fe II type nova in M31. The spectrum has been uploaded to the Transient Name Server: https://www.wis-tns.org/system/files/uploaded/F.%20D.%20Romanov/tns_2022ouu_classrep_13073_F._D._Romanov.jpg
The Liverpool Telescope is operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias with financial support from the UK Science and Technology Facilities Council.
AT 2022ouu = PNV J00423928+4115169 at CBAT TOCP
