AstroNote 2022-115

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DRAFT
2022-05-24 14:11:19
Type: Object/s-Discovery/Classification
ATLAS22olj (AT2022kms): discovery of a transient object in NGC 0055 (2 Mpc)
Authors: K. W. Smith, S. Srivastav, D. R. Young, S. J. Smartt, J. Gillanders, M. Fulton, M. McCollum, T. Moore (Queen's University Belfast), L. Shingles (GSI/QUB), L. Denneau, J. Tonry, H. Weiland (IfA, University of Hawaii), N. Erasmus, W. Koorts (South African Astronomical Observatory), J. Anderson (ESO), A. Jordan, V. Suc (UAI, Obstech), A. Rest (STScI), T.-W. Chen (Stockholm), M. Nicholl (Birmingham), C. Stubbs (Harvard)
Source Group: ATLAS
Keywords: Supernova
Abstract:
Here we report the ATLAS discovery of the transient ATLAS22olj (AT2022kms) in galaxy NGC 0055 at magnitude m_o = 18.59 +/- 0.16. At a distance of 2 Mpc, the transient was discovered on MJD = 59723.15 (2022-05-24.15) with an absolute magnitude of M = -7.43 +/- 0.16. There was a marginal detection through forced photometry on MJD = 59716.39 (before which there was an observation gap). Spectroscopic classification is encouraged.

ATLAS is a quadruple 0.5m telescope system with two units in Hawaii (Haleakala and Mauna Loa), and one each in Chile (El Sauce) and South Africa (Sutherland), see  Tonry et al. 2018, (PASP,130:064505). With the installation of the two southern units, we are robotically surveying the whole sky with a cadence of 1 day between -50 and +50 and 2 days in the polar regions, weather permitting. Two filters are used, cyan and orange (denoted c and o; all mags quoted are in the AB system). While carrying out the primary mission for Near-Earth Objects, we search for and publicly report stationary transients to the IAU Transient Name Server.  Data processing is carried out at Queen's University which combines automated source parameter filtering, machine learning image recognition, and spatial cross-matching with astronomical catalogues (Smith et al. 2020, PASP, 132:085002). More information is on the ATLAS homepage. We are submitting AstroNotes for transients that are either within 100 Mpc, or have some other interesting feature to bring to the community's attention, such as bright nuclear transients, slowly rising or rapidly fading objects.

We report a new transient source, most likely a nova in galaxy NGC 0055. We discovered ATLAS22olj (AT2022kms) on MJD 59723.15 == 2022-05-24.15, at m_o = 18.59 +/- 0.16. There was a marginal detection by ATLAS on MJD 59716.39 == 2022-05-17.39, before which there was a 32 day observation gap. ATLAS22olj is offset by 94.4 arcsec south, 244.3 arcsec east from NGC 0055, which is at z = 0.0004 or d = 2 Mpc (from NED), implying an absolute magnitude of M = -7.43 (assuming m-M = 25.99 and A_r = 0.03 and A_i = 0.02). Followup observations are encouraged.

The Asteroid Terrestrial-impact Last Alert System (ATLAS) project is primarily funded to search for Near-Earth asteroids through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575; byproducts of the NEO search include images and catalogs from the survey area. This work was partially funded by Kepler/K2 grant J1944/80NSSC19K0112 and HST GO-15889, and STFC grants ST/T000198/1 and ST/S006109/1. The ATLAS science products have been made possible through the contributions of the University of Hawaii Institute for Astronomy, the Queen's University Belfast, the Space Telescope Science Institute, the South African Astronomical Observatory, and The Millennium Institute of Astrophysics (MAS), Chile. 

Show current TNS values
CatalogNameReported RAReported DECReported Obj-TypeReported RedshiftHost NameHost RedshiftRemarksTNS RATNS DECTNS Obj-TypeTNS Redshift
TNS2022kms [ATLAS22olj]00:15:14.619-39:13:22.27NGC 00550.00043700:15:14.669-39:13:22.47