DRAFT
2022-06-09 07:53:39
Type: Object/s-Discovery/Classification
Classification of AT2022lnd as a rapidly fading Galactic CV
Authors: M. E. Huber (IfA, Univ. Hawaii), M. Fulton (QUB), T.-W. Chen (Stockholm), S. Srivastav, S. J. Smartt, K. W. Smith, D. R. Young, S. A. Sim, J. Gillanders, T. Moore (QUB), L. Shingles (GSI/QUB), M. Pursiainen (DTU), H. Kuncarayakti (Turku), K. C. Chambers, A. S. B. Schultz, T. de Boer, J. Bulger, J. Fairlamb, H. Gao, C. C. Lin, T. Lowe, E. Magnier , R. J. Wainscoat (IfA, Univ. Hawaii), A. Rest (STScI), C. Stubbs (Harvard), M. Nicholl (Birmingham)
Source Group: OxQUB
Abstract:
We report the classification of AT2022lnd as a rapidly fading galactic CV. Spectroscopic observations were performed on MJD 59735.95 (2022-06-05.95) with ALFOSC on the Nordic Optical telescope (NOT) and on MJD 59737.41 (2022-06-07.41) with GMOS on the Gemini North telescope. The initial NOT spectrum showed a blue featureless continuum, while the higher S/N Gemini spectrum revealed doubled-peaked H-alpha and He-I emission lines at rest wavelength. The combined ATLAS, Pan-STARRS and ZTF photometry show AT2022lnd to be blue and rapidly fading.

ZTF discovered AT2022lnd on MJD 59729.37 (2022-05-30.37), and we independently detected it in Pan-STARRS on MJD 59731.34 (2022-06-01.34). The combined ATLAS, Pan-STARRS and ZTF forced photometry shows a blue transient, with a two-day rise followed by a rapid fade. The last deep non-detection by ZTF occurred on MJD 59726.40 (2022-05-27.40). AT2022lnd is coincident (within 0.7") with what appears to be an extended and faint blue host object (see AstroNote #2022-121).


A spectrum was obtained on MJD 59735.95 (2022-06-05.95) with the ALFOSC instrument at the 2m Nordic Optical Telescope revealing a featureless blue continuum. Further data were taken on MJD 59737.41 (2022-06-07.41) with the GMOS on the Gemini-N telescope using the R400 grating and the GG455 blocking filter. This higher S/N spectrum revealed double-peaked H-alpha and He-I (6678A) emission lines at rest wavelength, indicating that AT2022lnd is of Galactic origin. The lines are intrinsically very weak and not visible above the noise of the NOT spectrum. The double-peaked nature of the emission lines is likely due to a dwarf nova accretion disc. 


The transient peaked in the Pan-STARRS w-band on MJD 59731.36 (2022-06-01.36) with m_w= 18.59 +/- 0.01. We followed up the transient on MJD 59733.43 (2022-06-03.43) measuring m_w = 19.21 +/-0.01, suggesting an initial decline rate of ~0.3 mag per day. Subsequent follow-up over the next five days revealed a consistantly fast-fading and blue transient; with m_r = 19.83 +/- 0.11, r-z = -0.22 +/- 0.20 and a decline rate of ~0.2 mag per day on MJD 59738.34 (2022-06-08.34).

We conclude that AT2022lnd is a CV, with a more rapid decline rate than the typical 0.1 mag per day, and the extended nature of the host object is most likely due to a stellar blend. 

Show current TNS values
Catalog Name Reported RA Reported DEC Reported Obj-Type Reported Redshift Host Name Host Redshift Remarks TNS RA TNS DEC TNS Obj-Type TNS Redshift
TNS 2022lnd [ZTF22aalwamk] 15:01:10.232 -06:50:36.25 CV 0 15:01:10.232 -06:50:36.25 CV

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