AstroNote 2021-105

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DRAFT
2021-03-28 18:23:57
Type: Object/s-Discovery/Classification
ZTF21aaquyjp/AT2021hel: ZTF discovery of a hostless fast transient
Authors: Igor Andreoni (Caltech), Michael Coughlin (UMN), Mansi Kasliwal (Caltech), Erik Kool (OKC), Tomas Ahumada (UMD), Shreya Anand (Caltech), Ana Sagues Carracedo (OKC)
Source Group: ZTF
Abstract:
We report the discovery of the fast optical transient ZTF21aaquyjp/AT2021hel with the Zwicky Transient Facility (ZTF). ZTF data at these coordinates are public and the light curve of ZTF21aaquyjp can be retrieved using brokers such as Lasair. ZTF21aaquyjp was first detected on 2021-03-27 12:20 UT at r=17.85 +- 0.11 mag. The last ZTF upper limit before the first detection was measured on 2021-03-24 12:50 UT, which constrains the onset time to be within < 3 days. ZTF21aaquyjp is fading by ~0.5 mag/day in r-band. The transient was last observed with ZTF on 2021-03-28 12:32 UT at r=18.366 +- 0.11 mag. No underlying source or possible host galaxy is cataloged in deep Legacy Survey DR9 and Pan-STARRS archival images. Previous activity was not found in the Pan-STARRS DR2 catalog and in ATLAS images, explored via the public forced photometry server. Multi-band photometry is currently unavailable for ZTF21aaquyjp. Follow-up observations are encouraged.

We report the discovery of the fast optical transient ZTF21aaquyjp/AT2021hel with the Zwicky Transient Facility (ZTF; Bellm et al. 2019, Graham et al. 2019) at coordinates:

RA = 21:05:10.73 (316.2947045d)
Dec = +12:49:24.74  (12.8235382d)

ZTF data at these coordinates are public and the light curve of ZTF21aaquyjp can be retrieved using brokers such as Lasair: https://lasair.roe.ac.uk/object/ZTF21aaquyjp/

ZTF21aaquyjp was first detected on 2021-03-27 12:20 UT at r=17.85 +- 0.11 mag. The last ZTF upper limit before the first detection was measured on 2021-03-24 12:50 UT, which constrains the onset time to be within < 3 days. ZTF21aaquyjp is fading by ~0.5 mag/day in r-band. The transient was last observed with ZTF on 2021-03-28 12:32 UT at r=18.366 +- 0.11 mag.

No underlying source or possible host galaxy is cataloged in deep Legacy Survey DR9 and Pan-STARRS (Chambers et al., 2016) archival images. 

Previous activity was not found in the Pan-STARRS DR2 catalog and in ATLAS images, explored via the public forced photometry server (Tonry et al., 2018; Smith et al., 2020).

Multi-band photometry is currently unavailable for ZTF21aaquyjp.


Follow-up observations are encouraged.


ZTF21aaquyjp was found by the ''ZTF Realtime Search and Triggering'' (ZTFReST) project, which aims at near real-time identification of compelling kilonova candidates in ZTF data using the methods described in Andreoni et al. (2020, ApJ, 904, 2), independently of gravitational-wave or gamma-ray triggers.

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.

Show current TNS values
CatalogNameReported RAReported DECReported Obj-TypeReported RedshiftHost NameHost RedshiftRemarksTNS RATNS DECTNS Obj-TypeTNS Redshift
Other2021hel [ZTF21aaquyjp]21:05:10.730+12:49:24.74