Optical Flux and Colour Variability of Blazars in the ZTF Survey
arXiv:2112.00790 · doi:10.1093/mnras/stab3591
Abstract
We investigate the temporal and colour variability of 897 blazars, comprising 455 BL Lacertae objects (BL Lacs) and 442 Flat Spectrum Radio Quasars (FSRQs), selected from the Roma-BZCAT catalogue, using the multi-band light curves from the Zwicky Transient Facility (ZTF DR6) survey. Assessing the colour variability characteristics over ~2 year timescales, we found that 18.5 per cent (84 out of 455) BL Lacs showed a stronger bluer when brighter (BWB) trend, whereas 9.0 per cent (41 out of 455) showed a redder when brighter (RWB) trend. The majority (70 per cent) of the BL Lacs showing RWB are host galaxy dominated. For the FSRQ subclass, 10.2 per cent (45 out of 442) objects showed a strong BWB trend and 17.6 per cent (78 out of 442) showed a strong RWB trend. Hence we find that BL Lacs more commonly follow a BWB trend than do FSRQs. This can be attributed to the more dominant jet emission in the case of BL Lacs and the contribution of thermal emission from the accretion disc for FSRQs. In analysing the colour behaviour on shorter time windows, we find many blazars evince shorter partial trends of BWB or RWB nature (or occasionally both). Some of such complex colour behaviours observed in the colour-magnitude diagrams of the blazars may result from transitions between the jet-dominated state to the disc-dominated state and vice versa.
arXiv commentAccepted for publication in MNRAS
References in corpus (27)
- Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
- Unified Schemes for Radio-Loud Active Galactic Nuclei
- The Zwicky Transient Facility: System Overview, Performance, and First Results
- The Zwicky Transient Facility: Data Processing, Products, and Archive
- On characterising the variability properties of X-ray light curves from active galaxies
- Active Galactic Nuclei: what's in a name?
- Turbulent, Extreme Multi-Zone Model for Simulating Flux and Polarization Variability in Blazars
- The transition between BL Lac objects and Flat Spectrum Radio Quasars
- The 5th edition of the Roma-BZCAT. A short presentation
- SMARTS optical and infrared monitoring of 12 gamma-ray bright blazars
- Multi-colour optical monitoring of eight red blazars
- Photopolarimetric Monitoring of Blazars in the Optical and Near-Infrared Bands with the Kanata Telescope. I. Correlations between Flux, Color, and Polarization
- The WEBT BL Lacertae Campaign 2001 and its extension
- Optical Intra-day Variability in Blazars
- Spectral Slope Variability of BL Lac Objects in the Optical Band
- Optical variability of the BL Lacertae object GC 0109+224. Multiband behaviour and time scales from a 7-years monitoring campaign
- The HST Survey of BL~Lacertae Objects. IV. Infrared Imaging of Host Galaxies
- A Consolidated Framework of the Color Variability in Blazars: Long-Term Optical/Near-Infrared Observations of 3C 279
- Short Term Flux and Colour Variations in Low-Energy Peaked Blazars
- The ZTF Source Classification Project: I. Methods and Infrastructure
- Temporal correlation between the optical and γ-ray flux variations in the blazar 3C 454.3
- Long-term optical-infrared color variability of blazars
- Multi-band optical variability of 3C 279 on diverse timescales
- Long term optical and infrared variability characteristics of Fermi Blazars
- Highly Variable Objects in the Palomar-QUEST Survey: A Blazar Search using Optical Variability
- The optical variability of steep-spectrum radio quasars in the SDSS Stripe 82 region
- Search for intra-day optical variability in Mrk 501