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New Insights into Blazar 1ES 1426+42.8 Through Optical Intraday Variability
Astronomers have recently made significant discoveries regarding the blazar 1ES 1426+42.8, revealing a phenomenon known as optical intraday variability (IDV). These findings were published in a paper featured in the September edition of the Monthly Notices of the Royal Astronomical Society, which could enhance our understanding of this intriguing celestial object.
Blazars are a specific type of quasar associated with supermassive black holes (SMBHs) situated at the centers of giant elliptical galaxies. They are classified as a subgroup of active galaxies, which contain active galactic nuclei (AGN) and are known for being the most prolific sources of extragalactic gamma-ray emissions. One of the defining characteristics of blazars is their relativistic jets, which are directed almost precisely towards Earth.
Astronomers categorize blazars into two primary groups based on their optical emissions: flat-spectrum radio quasars (FSRQs) that display broad optical emission lines, and BL Lacertae objects (BL Lacs), which lack these prominent features. The specific blazar 1ES 1426+42.8 is recognized as a BL Lac with a redshift of 0.129, having been discovered in 1984. It is identified as an extreme TeV source known for its low power and a high synchrotron peak exceeding 100 keV. Prior studies have mainly concentrated on its high-energy emissions, leaving its optical characteristics relatively unexplored.
In an effort to bridge this gap, a research team led by Xin Chang from Yunnan University in China conducted optical observations of 1ES 1426+42.8 using a 1.02-meter telescope over 16 nights between 2021 and 2023.
During these observations, Chang’s team noted instances of intraday variability occurring on seven separate days. They found that the variations in brightness were sporadic, with no clear relationship identified between the intensity of light and the presence of IDV.
The researchers postulated that the IDV detected could be attributed to individual synchrotron pulses originating from turbulence within the blazar’s jet. Their analysis suggested a total of 80 individual pulses. The calculated sizes of these turbulent radiation cells varied between 2.58 and 54.52 astronomical units (AU), indicating a complex structure of turbulence throughout the jet.
Additionally, the study recorded a potentially short-lived quasi-periodic oscillation (QPO) within the light curve of 1ES 1426+42.8. This QPO was observed on April 26, 2022, and exhibited a period of about 58.55 minutes. Such oscillations are typically associated with X-ray emissions that occur in proximity to the inner edges of an accretion disk, where gas spirals towards a compact celestial body, such as a neutron star or a black hole.
More information: Xin Chang et al, Optical intraday variability analysis for the BL Lacertae object 1ES 1426+42.8, Monthly Notices of the Royal Astronomical Society (2024). DOI: 10.1093/mnras/stae1839
Source
phys.org