Mid-infrared variability of ?-ray emitting blazars

Title

Mid-infrared variability of ?-ray emitting blazars

Creator

Anjum A.; Stalin C.S.; Rakshit S.; Gudennavar S.B.; Durgapal A.

Description

Using data from the Wide-field Infrared Survey Explorer, we studied the mid-infrared (mid-IR) 3.4 ?m (W1-band) and 4.6 ?m (W2-band) flux variability of ? -ray emitting blazars. Our sample consists of 460 flat spectrum radio quasars (FSRQs) and 575 BL Lacertae (BL Lac) objects. On intraday time-scales, the median amplitude of variability (? m) for FSRQs is 0.04+0.03?0.02 and 0.05+0.03?0.02 mag in W1 and W2 bands. For BL Lacs, we found median ? m in W1(W2) bands of 0.04+0.01?0.02 (0.04+0.02?0.02) mag. On long time-scales, for FSRQs we found a median ? m of 0.44+0.28?0.27 and 0.45+0.27?0.27 mag in W1 and W2 bands, while for BL Lacs, the median values are 0.21+0.18?0.12 and 0.22+0.18?.011 mag in W1 and W2 bands. From statistical tests, we found FSRQs to show larger ? m than BL Lacs on both intraday and long time-scales. Among blazars, low synchrotron peaked sources showed larger ? m compared to intermediate synchrotron peaked and high synchrotron peaked sources. The larger ? m seen in FSRQs relative to BL Lacs on both intraday and long time-scales could be due to them having the most powerful relativistic jets and/or their mid-IR band coinciding with the peak of the electron energy distribution. BL Lacs have low power jets and the observational window too traces the emission from low-energy electrons, thereby leading to low ? m. In both FSRQs and BL Lacs predominantly a bluer when brighter behaviour was observed. No correlation is found between ? m and black hole mass. 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

Source

Monthly Notices of the Royal Astronomical Society, Vol-494, No. 1, pp. 764-774.

Date

2020-01-01

Publisher

Oxford University Press

Subject

BL Lacertae objects: general; Galaxies: active; Galaxies: jets; Infrared: galaxies

Coverage

Anjum A., Department of Physics and Electronics, CHRIST (Deemed to be University), Bangalore Central Campus, Bengaluru, 560029, India; Stalin C.S., Indian Institute of Astrophysics, Block II, Koramangala, Bengaluru, 560034, India; Rakshit S., Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Quantum, Vesilinnantie 5, Turku, FI-20014, Finland; Gudennavar S.B., Department of Physics and Electronics, CHRIST (Deemed to be University), Bangalore Central Campus, Bengaluru, 560029, India; Durgapal A., Center of Advanced Study, Department of Physics, D. S. B. Campus, Kumaun University, Nainital, 263002, India

Rights

All Open Access; Green Open Access

Relation

ISSN: 358711; CODEN: MNRAA

Format

Online

Language

English

Type

Review

Identifier

https://doi.org/10.1093/mnras/staa771

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