VizieR Online Data Catalog: Optical and UV follow-up of 1ES 1927+654 (Trakhtenbrot+, 2019)
Abstract
An increase in optical flux from 1ES 1927+654 was discovered on 2018 March 3. The transient event was reported as ASASSN-18el and given the name AT 2018zf by the transient name server. Pre-discovery detections from 2017 December 23 were recovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) and designated as ATLAS18mgv. In what follows, we adopt this earlier ATLAS pre-discovery measurement as the detection date.
Following the sudden optical flux increase, we initiated a near-UV (NUV) and X-ray monitoring campaign using the Neil Gehrels Swift Observatory (PI: I. Arcavi). The host flux in the NUV UVW1 and UVM2 bands was determined from XMM-Newton/Optical Monitor (OM) data obtained in 2011 May 20 (Gallo+ 2013MNRAS.433..421G AB magnitudes of 18.14 and 18.65, respectively, using the same aperture), and subtracted from our new UVOT measurements. The X-ray analysis is discussed in detail in a companion paper (C. Ricci+ 2021, arXiv:2102.05666). We obtained optical spectra of 1ES 1927+654 with the Ohio State Multi-Object Spectrograph (OSMOS) mounted on the Hiltner 2.4m Telescope at the MDM Observatory; the Spectrograph for the Rapid Acquisition of Transients (SPRAT) instrument mounted on the 2m Liverpool Telescope at the Roque de los Muchachos Observatory; the Kast spectrograph mounted on the 3m Shane Telescope at the Lick Observatory; the FLOYDS spectrograph mounted on the 2m Faulkes Telescope North at Haleakala, Hawaii (part of the Las Cumbres Observatory network); the Dual Imaging Spectrograph mounted on the Apache Point Observatory 3.5m telescope; the Low Resolution Imaging Spectrograph (LRIS) mounted on the Keck I telescope at Maunakea; and the Double Beam Spectrograph (DBSP) mounted on the Palomar Hale 5m telescope. We also obtained far-UV (FUV) and NUV spectra of 1ES 1927+654 using the Cosmic Origins Spectrograph (COS) and Space Telescope Imaging Spectrograph (STIS) instruments, respectively, on board the Hubble Space Telescope (HST; Program ID 15604, PI: C.L. MacLeod). A log of all our spectral observations of 1ES 1927+654 is detailed in Table 1. (4 data files).- Publication:
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VizieR Online Data Catalog
- Pub Date:
- March 2021
- DOI:
- 10.26093/cds/vizier.18830094
- Bibcode:
- 2021yCat..18830094T
- Keywords:
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- Active gal. nuclei;
- Spectra: optical;
- Photometry: ultraviolet;
- X-ray sources