Show simple item record

Files in this item


Item metadata

dc.contributor.authorKhatu, Viraja C.
dc.contributor.authorGallagher, Sarah C.
dc.contributor.authorHorne, Keith
dc.contributor.authorCackett, Edward M.
dc.contributor.authorHu, Chen
dc.contributor.authorDu, Pu
dc.contributor.authorWang, Jian-Min
dc.contributor.authorBian, Wei-Hao
dc.contributor.authorBai, Jin-Ming
dc.contributor.authorChen, Yong-Jie
dc.contributor.authorHall, Patrick
dc.contributor.authorJiang, Bo-Wei
dc.contributor.authorLi, Sha-Sha
dc.contributor.authorLi, Yan-Rong
dc.contributor.authorPasquini, Sofia
dc.contributor.authorSongsheng, Yu-Yang
dc.contributor.authorWang, Chan
dc.contributor.authorXiao, Ming
dc.contributor.authorYu, Zhe
dc.identifier.citationKhatu , V C , Gallagher , S C , Horne , K , Cackett , E M , Hu , C , Du , P , Wang , J-M , Bian , W-H , Bai , J-M , Chen , Y-J , Hall , P , Jiang , B-W , Li , S-S , Li , Y-R , Pasquini , S , Songsheng , Y-Y , Wang , C , Xiao , M & Yu , Z 2023 , ' Revisiting emission-line measurement methods for narrow-line active galactic nuclei ' , Publications of the Astronomical Society of the Pacific , vol. 135 , no. 1046 , 044504 .
dc.identifier.otherJisc: 1056795
dc.identifier.otherpublisher-id: paspacc973
dc.identifier.othermanuscript: acc973
dc.identifier.otherother: pasp-101514.r2
dc.descriptionFunding: The authors acknowledge the support of the Natural Sciences and Engineering Research Council of Canada (NSERC), Discovery Grant RGPIN/04157. V.C.K. acknowledges the support of the Ontario Graduate Scholarships. C.H. acknowledges support from the National Science Foundation of China (12122305). P.D. acknowledges financial support from National Science Foundation of China grants NSFC-12022301, -11873048, and -11991051. The research of V.C.K. was partially supported by the New Technologies for Canadian Observatories, an NSERC CREATE program. We acknowledge the support of the National Key R&D Program of China No. 2021YFA1600404 and the National Science Foundation of China (11991054, 11833008, 11991051, 11973029).en
dc.description.abstractMeasuring broad emission-line widths in active galactic nuclei (AGN) is not straightforward owing to the complex nature of flux variability in these systems. Line width measurements become especially challenging when the signal-to-noise ratio is low, profiles are narrower, or spectral resolution is low. We conducted an extensive correlation analysis between emission-line measurements from the optical spectra of Markarian 142 (Mrk 142; a narrow-line Seyfert galaxy) taken with the Gemini North Telescope (Gemini) at a spectral resolution of 185.6 ± 10.2 km s−1 and the Lijiang Telescope (LJT) at 695.2 ± 3.9 km s−1 to investigate the disparities in the measured broad-line widths from both telescopes’ data. Due to its narrow broad-line profiles, which were severely affected by instrumental broadening in the lower-resolution LJT spectra, Mrk 142 posed a challenge. We discovered that allowing the narrow-line flux of permitted lines having broad and narrow components to vary during spectral fitting caused a leak in the narrow-line flux to the broad component, resulting in broader broad-line widths in the LJT spectra. Fixing the narrow-line flux ratios constrained the flux leak and yielded the Hβ broad-line widths from LJT spectra ∼54% closer to the Gemini Hβ widths than with flexible narrow-line ratios. The availability of spectra at different resolutions presented this unique opportunity to inspect how spectral resolution affected emission-line profiles in our data and adopt a unique method to accurately measure broad-line widths. Reconsidering line measurement methods while studying diverse AGN populations is critical for the success of future reverberation-mapping studies. Based on the technique used in this work, we offer recommendations for measuring line widths in narrow-line AGN.
dc.relation.ispartofPublications of the Astronomical Society of the Pacificen
dc.subjectQB Astronomyen
dc.titleRevisiting emission-line measurement methods for narrow-line active galactic nucleien
dc.typeJournal articleen
dc.contributor.institutionUniversity of St Andrews. School of Physics and Astronomyen
dc.contributor.institutionUniversity of St Andrews. St Andrews Centre for Exoplanet Scienceen
dc.description.statusPeer revieweden

This item appears in the following Collection(s)

Show simple item record