Improving the flux calibration in reverberation mapping by spectral fitting: application to the Seyfert galaxy MCG-6-30-15

Journal Article · Thu Dec 01 04:00:00 EST 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/832/2/197· OSTI ID:22868385

Hu, Chen; Wang, Jian-Min; Li, Yan-Rong; Du, Pu; Lu, Kai-Xing ^[1]; Ho, Luis C. ^[2]; Bai, Jin-Ming ^[3]

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1. Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquan Road, Beijing 100049 (China)
2. Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)
3. Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China)

We propose a method for the flux calibration of reverberation mapping spectra, based on accurate measurement of [O iii] λ5007 emission by spectral fitting. Our method can achieve better accuracy than the traditional method of Groningen and Wanders, allowing reverberation mapping measurements for objects with variability amplitudes as low as ∼5%. As a demonstration, we reanalyze the data of the Seyfert 1 galaxy MCG–6-30-15, taken from the 2008 campaign of the Lick active galactic nucleus monitoring project, which previously failed to obtain a time lag for this weakly variable object, owing to a relatively large flux calibration uncertainty. We detect a statistically significant rest-frame time lag of 6.38{sub −2.69}{sup +3.07} days between the Hβ and V-band light curves. Combining this lag with FWHM(Hβ) = 1933 ± 81 km s{sup −1} and a virial coefficient of f = 0.7, we derive a virial black hole mass of 3.26{sub −1.40}{sup +1.59}×10{sup 6} M {sub ⊙}, which agrees well with previous estimates by other methods.

• OSTI ID: 22868385
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 832; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCURACY
BLACK HOLES
CALIBRATION
DATA ANALYSIS
EMISSION
GALAXY NUCLEI
MASS
SEYFERT GALAXIES
SPECTRA