Long-term optical spectroscopic variations in blazar 3C 454.3

doi:10.1051/0004-6361/201935904

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	Long-term optical spectroscopic variations in blazar 3C 454.3
	Nalewajko, Krzysztof 1; Gupta, Alok C.2; Liao, Mai 3,4; Hryniewicz, Krzysztof 1; Gupta, Maitrayee 1; Gu, Minfeng 3
刊名	ASTRONOMY & ASTROPHYSICS
	2019-10-11
卷号	631 页码:8
关键词	galaxies: active quasars: emission lines quasars: individual: 3C 454.3
ISSN号	0004-6361
DOI	10.1051/0004-6361/201935904
英文摘要	Aims. Characterisation of the long-term variations in the broad line region in a luminous blazar, where Comptonisation of broadline emission within a relativistic jet is the standard scenario for production of gamma-ray emission that dominates the spectral energy distribution. Methods. We analysed ten years of optical spectroscopic data from the Steward Observatory for the blazar 3C 454.3, as well as gamma-ray data from the Fermi Large Area Telescope (LAT). The optical spectra are dominated by a highly variable non-thermal synchrotron continuum with a prominent Mg II broad emission line. The line flux was obtained by spectral decomposition including significant contribution from the Fe II pseudo-continuum. Three methods were used to characterise variations in the line flux: (1) stacking of the continuum-subtracted spectra, (2) subtracting the running mean light curves calculated for different timescales, and (3) evaluating potential time delays via the discrete correlation function (DCF). Results. Despite very large variations in the gamma-ray and optical continua, the line flux changes only moderately (<0.1 dex). The data suggest that the line flux responds to a dramatic change in the blazar activity from a very high state in 2010 to a deep low state in 2012. Two interpretations are possible: either the line flux is anti-correlated with the continuum or the increase in the line luminosity is delayed by similar to 600 days. If this time delay results from the reverberation of poorly constrained accretion disc emission in both the broad-line region (BLR) and the synchrotron emitting blazar zone within a relativistic jet, we would obtain natural estimates for the BLR radius R-BLR,R-MgII greater than or similar to 0.8 pc and for the supermassive black hole mass M-SMBH similar to 8.5 x 10(8) M-circle dot. We did not identify additional examples of short-term "flares" of the line flux, in addition to the previously reported case observed in 2010.
资助项目	Fermi Guest Investigator grants[NNX08AW56G] ; Fermi Guest Investigator grants[NNX09AU10G] ; Fermi Guest Investigator grants[NNX12AO93G] ; Fermi Guest Investigator grants[NNX15AU81G] ; Polish National Science Centre grant[2015/18/E/ST9/00580] ; Polish National Science Centre grant[2015/17/B/ST9/03422] ; Indo-Poland project - Department of Science and Technology (DST) of the Government of India[DST/INT/POL/P19/2016] ; Chinese Academy of Sciences (CAS) President's International Fellowship Initiative (PIFI) grant[2016VMB073] ; National Science Foundation of China[11873073] ; National Science Foundation of China[U1531245] ; National Science Foundation of China[11773056] ; National Science Foundation of China[U1831138]
WOS关键词	SPACE-TELESCOPE OBSERVATIONS ; BROAD-LINE REGION ; MULTIWAVELENGTH OBSERVATIONS ; INFRARED OBSERVATIONS ; XMM-NEWTON ; RAY FLARE ; VARIABILITY ; EMISSION ; RADIATION ; 3C-454.3
WOS研究方向	Astronomy & Astrophysics
语种	英语
出版者	EDP SCIENCES S A
WOS记录号	WOS:000515084100001
资助机构	Fermi Guest Investigator grants ; Fermi Guest Investigator grants ; Polish National Science Centre grant ; Polish National Science Centre grant ; Indo-Poland project - Department of Science and Technology (DST) of the Government of India ; Indo-Poland project - Department of Science and Technology (DST) of the Government of India ; Chinese Academy of Sciences (CAS) President's International Fellowship Initiative (PIFI) grant ; Chinese Academy of Sciences (CAS) President's International Fellowship Initiative (PIFI) grant ; National Science Foundation of China ; National Science Foundation of China ; Fermi Guest Investigator grants ; Fermi Guest Investigator grants ; Polish National Science Centre grant ; Polish National Science Centre grant ; Indo-Poland project - Department of Science and Technology (DST) of the Government of India ; Indo-Poland project - Department of Science and Technology (DST) of the Government of India ; Chinese Academy of Sciences (CAS) President's International Fellowship Initiative (PIFI) grant ; Chinese Academy of Sciences (CAS) President's International Fellowship Initiative (PIFI) grant ; National Science Foundation of China ; National Science Foundation of China ; Fermi Guest Investigator grants ; Fermi Guest Investigator grants ; Polish National Science Centre grant ; Polish National Science Centre grant ; Indo-Poland project - Department of Science and Technology (DST) of the Government of India ; Indo-Poland project - Department of Science and Technology (DST) of the Government of India ; Chinese Academy of Sciences (CAS) President's International Fellowship Initiative (PIFI) grant ; Chinese Academy of Sciences (CAS) President's International Fellowship Initiative (PIFI) grant ; National Science Foundation of China ; National Science Foundation of China ; Fermi Guest Investigator grants ; Fermi Guest Investigator grants ; Polish National Science Centre grant ; Polish National Science Centre grant ; Indo-Poland project - Department of Science and Technology (DST) of the Government of India ; Indo-Poland project - Department of Science and Technology (DST) of the Government of India ; Chinese Academy of Sciences (CAS) President's International Fellowship Initiative (PIFI) grant ; Chinese Academy of Sciences (CAS) President's International Fellowship Initiative (PIFI) grant ; National Science Foundation of China ; National Science Foundation of China
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/54321]
专题	中国科学院国家天文台
通讯作者	Nalewajko, Krzysztof
作者单位	1.Polish Acad Sci, Nicolaus Copernicus Astron Ctr, Bartycka 18, PL-00716 Warsaw, Poland 2.Aryabhatta Res Inst Observat Sci ARIES, Manora Peak 263002, Nainital, India 3.Chinese Acad Sci, Shanghai Astron Observ, Key Lab Res Galaxies & Cosmol, Shanghai 200030, Peoples R China 4.Univ Chinese Acad Sci, 19A Yuquanlu, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Nalewajko, Krzysztof,Gupta, Alok C.,Liao, Mai,et al. Long-term optical spectroscopic variations in blazar 3C 454.3[J]. ASTRONOMY & ASTROPHYSICS,2019,631:8.
APA	Nalewajko, Krzysztof,Gupta, Alok C.,Liao, Mai,Hryniewicz, Krzysztof,Gupta, Maitrayee,&Gu, Minfeng.(2019).Long-term optical spectroscopic variations in blazar 3C 454.3.ASTRONOMY & ASTROPHYSICS,631,8.
MLA	Nalewajko, Krzysztof,et al."Long-term optical spectroscopic variations in blazar 3C 454.3".ASTRONOMY & ASTROPHYSICS 631(2019):8.