We have been submitting AstroNotes for ATLAS transients (Smith et al. 2020 arXiv:2003.09052) 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 would like to bring to the attention of the community a candidate supernova in the nearby galaxy ESO 515- G 004. The transient AT2020fsb was discovered by ZTF on MJD 58941.42 == 2020-04-02.42 at r = 16.57 +/- 0.04 and was reported to the TNS by ALeRCE. The transient was subsquently detected by ATLAS 3hrs later n MJD 58941.55 == 2020-04-02.55, at m_c = 16.72 +/- 0.02. There was no detection by ATLAS on MJD 58929.61 == 2020-03-21.61. No useful pre-discovery data is available from ZTF.
https://lasair.roe.ac.uk/object/ZTF20aaunfpj/
https://alerce.online/object/ZTF20aaunfpj
The host galaxy is at a redshift of z = 0.008 or d = 33 Mpc (from NED), implying an absolute magnitude of M = -16.6 (assuming m-M = 32.60 and A_g = 0.84 and A_r = 0.58). The host is an irregular blue galaxy. The transient may be intriniscally faint, or a young, rising supernova.
Followup observations are encouraged.
| 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 | 2020fsb [ZTF20aaunfpj] | 15:39:03.810 | -25:58:28.34 | ESO 515- G 004 | 0.007515 | 15:39:03.810 | -25:58:28.34 | SN II | 0.007515 |


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