AT 2017fvz: a nova in the dwarf irregular galaxy NGC 6822

Abstract

A transient in the Local Group dwarf irregular galaxy NGC 6822 (Barnard's Galaxy) was discovered on 2017 August 2 and is only the second classical nova discovered in that galaxy. We conducted optical, near-ultraviolet, and X-ray follow-up observations of the eruption, the results of which we present here. This 'very fast' nova had a peak $V$-band magnitude in the range $-7.41>M_V>-8.33$ mag, with decline times of $t_{2,V}=8.1\pm 0.2$ d and $t_{3,V}=15.2\pm 0.3$ d. The early- and late-time spectra are consistent with an Fe II spectral class. The H$\alpha$ emission line initially has a full width at half-maximum intensity of $\sim 2400$ km s${}^{-1}$ - a moderately fast ejecta velocity for the class. The H$\alpha$ line then narrows monotonically to $\sim 1800$ km s${}^{-1}$ by 70 d post-eruption. The lack of a pre-eruption coincident source in archival Hubble Space Telescope imaging implies that the donor is a main sequence, or possibly subgiant, star. The relatively low peak luminosity and rapid decline hint that AT 2017fvz may be a 'faint and fast' nova.

15 pages, 7 figures, accepted for publication in MNRAS

References in corpus (11)

• A Universal Decline Law of Classical Novae
• The Super-Soft X-ray Phase of Nova RS Ophiuchi 2006
• M31N 2008-12a - the remarkable recurrent nova in M31: Pan-chromatic observations of the 2015 eruption
• Identifying and Quantifying Recurrent Novae Masquerading as Classical Novae
• A UV and optical study of 18 old novae with Gaia DR2 distances: mass accretion rates, physical parameters, and MMRD
• Observations of the GRB afterglow ATLAS17aeu and its possible association with GW170104
• M31N 2007-11d: A Slowly-Rising, Luminous Nova in M31
• A New Cepheid Distance Measurement and Method for NGC 6822
• Multiwavelength observations of nova SMCN 2016-10a --- one of the brightest novae ever observed
• On the progenitors of Local Group Novae - I. The M31 Catalog
• Multi-wavelength Observations of the 2015 Nova in the Local Group Irregular Dwarf Galaxy IC 1613

Cited by in corpus (2)

• AT 2016dah and AT 2017fyp: the first classical novae discovered within a tidal stream
• AT 2023prq: A Classical Nova in the Halo of the Andromeda Galaxy