2018 Fiscal Year Annual Research Report
Understanding the growth of low-mass black holes and its role in galaxy evolution
| Project/Area Number |
17F17321
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| Research Institution | Kyoto University |
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Principal Investigator |
上田 佳宏 京都大学, 理学研究科, 准教授 (10290876)
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| Co-Investigator(Kenkyū-buntansha) |
OH KYUSEOK 京都大学, 理学(系)研究科(研究院), 外国人特別研究員
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| Project Period (FY) |
2017-11-10 – 2020-03-31
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| Keywords | ブラックホール / 活動銀河核 |
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| Outline of Annual Research Achievements |
In the fiscal year of 2018, the achievements can be summarised as follows: 1) several hundreds of a new and high-resolution optical / near-IR spectra, 2) presentations in the domestic / international conferences under the support by KAKENHI, and 3) publication of new work (under peer review).
(1) We obtained nearly 300 new optical spectra reaching to near-IR that have not been achieved yet. These new high-resolution spectra from ESO VLT X-shooter are a part of hard X-ray selected AGN. As a PI and co-I of successful observing programs (and ongoing program) since 2016, Dr. Oh is in charge of observing proposal planning, design, phase 2 submission, data reduction, and spectral line measurements. With other ~500 new optical spectra obtained from Palomar, SOAR, and duPont, we are covering complete set of optical spectra of local hard X-ray selected AGN (N~840, 100%).
(2) Under the support by KAKENHI, Dr. Oh have presented researches in the Korean domestic conferences (2 times) and international conferences (Japan, Taiwan, USA, 3 times). By making use of these precious opportunities, Dr. Oh has been collaborate with international researchers discussing current research projects and future works.
(3) A new research work is submitted to the journal (under peer-review). In this work, we investigated how AGN growth rate is related with narrow emission-line ratios in high-redshift. Also, we have shown that how such relationship is different from our previous collaboration (Oh, K., Ueda, Y. et al. 2017).
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Under the KAKENHI supports, several hundreds of new and high-resolution optical / near-IR spectra are obtained. These unique set of AGN sample chosen from the ultra-hard X-ray and its optical spectra have never been achieved. In this pioneering work, Dr. Oh is building each spectral block to establish demographic study of the least biased sample of AGN in the local Universe. The newly obtained optical / near-IR spectra are under the analysis: spectral line measurements, BPT diagnostics diagrams, data visualization.
The observing application aiming to use Swift/XRT soft X-ray instrument (cycle 14) was not successful. Soft X-ray observation in the energy range of 2-10 keV is used as direct evidence of catching active nuclear activity for extremely low-mass galaxies. Since these low-mass galaxies feature very weak optical signature of black hole activity (i.e., Balmer broad-lines), X-ray observation would be required.
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| Strategy for Future Research Activity |
In this year, we will apply for soft X-ray observations of low-mass local black holes to Swift/XRT. The improved application will enable us to directly catch nuclear activity and confirm its AGN nature, allowing us to estimate reliable AGN bolometric luminosity which holds a key physical parameter in the study.
Beside, we will improve the current spectral line analysis using recently obtained optical / near-IR spectra. Spectral line fitting quality assessment for the whole sample will be established. This massive efforts will be out as a official data release of the current international collaboration, the BAT AGN Spectroscopic Survey.
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