NuStar. Hard X-Ray View of Low-luminosity Active Galactic Nuclei: High-energy Cutoff and Truncated Thin Disk

doi:10.3847/1538-4357/aaf38b

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	NuStar. Hard X-Ray View of Low-luminosity Active Galactic Nuclei: High-energy Cutoff and Truncated Thin Disk
	Younes, George 1,8; Ptak, Andrew 2; Ho, Luis C.3,6; Xie, Fu-Guo 7; Terasima, Yuichi 9; Yuan, Feng 7; Huppenkothen, Daniela 5; Yukita, Mihoko 2,4
刊名	ASTROPHYSICAL JOURNAL
	2019-01-10
卷号	870 期号:2 页码:12
关键词	galaxies: active galaxies: individual (NGC 3998, NGC 4579)
ISSN号	0004-637X
DOI	10.3847/1538-4357/aaf38b
英文摘要	We report the analysis of simultaneous XMM-Newton+Nuclear Spectroscopic Telescope Array (NuSTAR) observations of two low-luminosity active galactic nuclei (LLAGNs), NGC 3998 and NGC 4579. We do not detect any significant variability in either source over the similar to 3 day length of the NuSTAR observations. The broadband 0.5-60 keV spectrum of NGC 3998 is best fit with a cutoff power law, while the one for NGC 4579 is best fit with a combination of a hot thermal plasma model, a power law, and a blend of Gaussians to fit an Fe complex observed between 6 and 7 keV. Our main spectral results are the following: (1) neither source shows any reflection hump with 3 sigma reflection fraction upper limits of R < 0.3 and R < 0.18 for NGC 3998 and NGC. 4579, respectively; (2) the 6-7 keV line complex in NGC 4579 could be fit with either a narrow Fe K line at 6.4 keV and a moderately broad Fe XXV line or with three relatively narrow lines, which include contribution from Fe XXVI; (3) the NGC 4579 flux is 60% brighter than previously detected with XMM-Newton, accompanied by a hardening in the spectrum; (4) we measure a cutoff energy E-cut = 107(-18)(+27) keV in NGC. 3998, which represents the lowest and best constrained high-energy cutoff ever measured for an LLAGN; (5) the NGC. 3998 spectrum is consistent with a Comptonization model with either a sphere (tau approximate to 3 +/- 1) or slab (tau approximate to 1.2 +/- 0.6) geometry, corresponding to plasma temperatures between 20 and 150 keV. We discuss these results in the context of hard X-ray emission from bright AGNs, other LLAGNs, and hot accretion flow models.
资助项目	NASA under NuSTAR Guest Observer cycle-2[15-NUSTAR215-0024] ; National Key R&D Program of China[2016YFA0400702] ; National Key R&D Program of China[2016YFA0400804] ; National Key R&D Program of China[2016YFA0400704] ; National Science Foundation of China[11473002] ; National Science Foundation of China[11721303] ; National Science Foundation of China[11873074] ; National Science Foundation of China[11573051] ; National Science Foundation of China[11633006] ; National Science Foundation of China[11650110427] ; National Science Foundation of China[11661161012] ; National Science Foundation of China[11303008] ; JSPS[15H02070] ; JSPS[16K05296] ; Key Research Program of Frontier Sciences of CAS[QYZDJSSW-SYS008] ; Key Research Program of Frontier Sciences of CAS[QYZDB-SSW-SYS033] ; Youth Innovation Promotion Association of CAS[2016243] ; Natural Science Foundation of Shanghai[17ZR1435800]
WOS研究方向	Astronomy & Astrophysics
语种	英语
出版者	IOP PUBLISHING LTD
WOS记录号	WOS:000455820100019
内容类型	期刊论文
源URL	[http://119.78.226.72/handle/331011/31973]
专题	中国科学院上海天文台
通讯作者	Younes, George
作者单位	1.George Washington Univ, Astron Phys & Stat Inst Sci, Washington, DC 20052 USA 2.NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA 3.Peking Univ, Kavli Inst Astron & Astrophys, Beijing 100871, Peoples R China 4.Johns Hopkins Univ, Homewood Campus, Baltimore, MD 21218 USA 5.Univ Washington, Dept Astron, 3910 15th Ave NE, Seattle, WA 98195 USA 6.Peking Univ, Sch Phys, Dept Astron, Beijing 100871, Peoples R China 7.Chinese Acad Sci, Shanghai Astron Observ, Key Lab Res Galaxies & Cosmol, 80 Nandan Rd, Shanghai 200030, Peoples R China 8.George Washington Univ, Dept Phys, Washington, DC 20052 USA 9.Ehime Univ, Dept Phys, Bunkyo Cho, Matsuyama, Ehime 7908577, Japan
推荐引用方式 GB/T 7714	Younes, George,Ptak, Andrew,Ho, Luis C.,et al. NuStar. Hard X-Ray View of Low-luminosity Active Galactic Nuclei: High-energy Cutoff and Truncated Thin Disk[J]. ASTROPHYSICAL JOURNAL,2019,870(2):12.
APA	Younes, George.,Ptak, Andrew.,Ho, Luis C..,Xie, Fu-Guo.,Terasima, Yuichi.,...&Yukita, Mihoko.(2019).NuStar. Hard X-Ray View of Low-luminosity Active Galactic Nuclei: High-energy Cutoff and Truncated Thin Disk.ASTROPHYSICAL JOURNAL,870(2),12.
MLA	Younes, George,et al."NuStar. Hard X-Ray View of Low-luminosity Active Galactic Nuclei: High-energy Cutoff and Truncated Thin Disk".ASTROPHYSICAL JOURNAL 870.2(2019):12.