ZTF Discovery of Highly Reddened Galactic Nova Candidate ZTF24aaomlxy
ATel #16658; Yuankun David Wang (UW) and Eric C. Bellm (UW) on behalf of the Zwicky Transient Facility Collaboration
on 15 Jun 2024; 19:57 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Eric Bellm (ecbellm@uw.edu)
Subjects: Optical, X-ray, Nova
We report the discovery of a Galactic nova candidate in the Zwicky Transient Facility alert stream (ZTF; Bellm et al. 2019, Graham et. al 2019) at J2000 coordinates 18:38:28.43 -08:53:27.26. ZTF detected the source (internally designated ZTF24aaomlxy) near peak brightness at m_r ~ 15.709 +/- 0.005 on 2024-05-19.376. An observation the same night in the ztf-g band showed m_g~20.238 +/- 0.249. The source is not detected in observations by ZTF on 2024-05-15.338 in ztf-r band, or in observations on 2024-05-17.419 in ztf-g band. Forced photometry using ATLAS (Tonry et al., 2018) shows detections just before peak on 2024-05-18.587. The source declined from peak by two magnitudes in the next 14 days. The source was last observed by ZTF on 2024-06-12.357 at m_r ~ 18.1 +/- 0.06. The closest PS1 and Gaia DR3 objects are 0.92â away so we do not find an obvious counterpart for this candidate.
A spectrum of the source taken using the KOSMOS spectrograph at Apache Point Observatory on 2024-06-07 shows an H-alpha line (FWHM about 1400 km/s), as well as strong O I and Ca II lines. Emission lines are possibly double peaked, but no P Cygni profiles are seen. Given the high level of extinction, only the spectrum between 5400-9600A was observed. We estimate the extinction Av to be around 14, assuming a visual extinction to reddening ratio of 3.1 and an E(B-V) ~ 4.5 (Schlafly & Finkbeiner 2011); this is consistent with an absolute magnitude around -7 for classical novae assuming galactic distances. An observation by Swift on 2024-06-13 established an upper limit on the 0.3-10 keV X-ray flux of 0.0058 ct/s.
Based on observations obtained with the Samuel Oschin Telescope 48-inch and the 60-inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the National Science Foundation under Grant No. AST-2034437 and a collaboration including Caltech, IPAC, the Weizmann Institute for Science, the Oskar Klein Center at Stockholm University, the University of Maryland, Deutsches Elektronen-Synchrotron and Humboldt University, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee, Trinity College Dublin, Lawrence Livermore National Laboratories, and IN2P3, France. Operations are conducted by COO, IPAC, and UW. The ZTF forced-photometry service was funded under the Heising-Simons Foundation grant #12540303 (PI: Graham).
We acknowledge further support from the Heising-Simons Foundation under grant 2018-0908.
