The Zwicky Transient Facility (ZTF; Bellm et al. 2019; Graham et al. 2019) Superluminous Supernova Science Program (Lunnan et al. 2020; Yan et al. 2020) reports 7 candidate SLSNe, following the methodology outlined by Perley et al. (in prep.) We selected transients that have a long rise time (>20 days), long duration, and/or a faint host galaxy. Due to recent ZTF downtime, constraints on the rising phase of the light curve are less robust than usual in this report.
We summarise properties of the candidates in the Related Objects Table. These include coordinates, current magnitudes, approximate rise times, photometric redshifts of potential host galaxies (taken from the SDSS DR14) and special remarks.
We will distribute alerts on such SLSN candidates via AstroNotes periodically; spectroscopic classifications and additional follow-up observations of these transients are encouraged.
This report is 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.
| 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 | 2022akq [ZTF22aaahsue] | 08:49:18.716 | +23:04:59.67 | First detected approximately 80 days ago. Shows no evolution in r-band but a slight fading in g-band; current magnitudes are r~19.8 and g~20.7. No underlying host galaxy is present at the location of the transient, although there are two extended sources within a few arcsec detected in the Legacy Survey with photometric redshifts of z=0.43 and z=0.81, respectively. | 08:49:18.716 | +23:04:59.67 | ||||||
| TNS | 2022hn [ZTF22aaafnyu] | 15:33:10.070 | -14:13:46.06 | A bright, slow, and relatively red transient (r~18.4, g~18.6 at discovery 60 days ago, now r~18.8, g~19.2) positionally coincident with the center of a galaxy with a compact blue core. The WISE colors and emission line ratios from spectroscopic follow-up are consistent with pure star-formation, with no evidence of an AGN. Spectra are featureless other than narrow host-galaxy emission lines. The spectroscopic redshift of 0.115 indicates a peak absolute magnitude of -20.8. | 15:33:10.070 | -14:13:46.06 | ||||||
| TNS | 2022hjf [ZTF22aabnpzt] | 13:19:19.494 | +57:04:54.87 | SDSS J131919.49+570454.7 | First detected 60 days ago at a magnitude close to the ZTF limit; has since brightened only slightly and become slightly redder and is now r~19.9, g~20.3. Positionally coincident with one component of a blended SDSS source, possibly representing an extreme star-forming region in the outer disk of a distant galaxy or an active merger. The photometric redshift is z = 0.28+/-0.06, which would imply an absolute magnitude between -20 and -21. An alternative possibility is that the source represents a QSO positionally coincident with a foreground galaxy. | 13:19:19.494 | +57:04:54.87 | |||||
| TNS | 2022hjg [ZTF22aabzfwr] | 12:38:39.207 | +22:58:37.59 | First detected 60 days ago at a magnitude close to the ZTF limit. Currently r~20.2, g~20.6, and has shown little brightening or fading since the initial detection, although photometric coverage is very sparse. The position is slightly offset from a blue, marginally-extended Legacy Survey DR9 source with photometric redshift of z = 0.42+/-0.18, which would imply an absolute magnitude between -20 and -22.4. | 12:38:39.216 | +22:58:37.67 | ||||||
| TNS | 2022eha [ZTF22aacedio] | 16:31:07.862 | +24:01:07.08 | Slow-evolving, very red source, first detected 60 days ago at r~20.7 and has since brightened to r~19.2, g~20; is now at peak or possibly still rising. Seen 15 arcseconds in projection from a bright spiral galaxy at z=0.0373 but may not be associated with it. There is otherwise no underlying source at or near the position of the transient in survey imaging. | 16:31:07.848 | +24:01:07.18 | ||||||
| TNS | 2022cfz [ZTF22aaalsqi] | 08:35:27.662 | +76:04:37.78 | Shows a relatively rapid rise from the last upper limit 80 days ago to the first detection 55 days ago but has faded only very slowly since and is now r~18.7, g~19.0. Spectra taken with P60/SEDM and LT/SPRAT show only a featureless blue continuum. There is no underlying source in deep Legacy Survey imaging, although there is a very bright (16 mag) foreground star 6 arcsec to the northwest. | 08:35:27.662 | +76:04:37.78 | ||||||
| TNS | 2022gyv [ZTF22aadqgoa] | 12:57:59.611 | +41:04:42.06 | The transient has remained at a constant magnitude of g~r~18.9 mag since its first detection 11 days ago. Despite upper limits reported in the ZTF avro history during the same timespan, LT imaging confirms that the source is genuine. No underlying host galaxy is detected to the limits of the Legacy Survey (>23.5 mag). | 12:57:59.611 | +41:04:42.06 | SLSN-I | 0.39 |
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