| 研究課題/領域番号 |
15K17604
|
|---|
| 研究機関 | 東京大学 |
|---|
研究代表者 |
RUJOPAKARN WIPHU 東京大学, カブリ数物連携宇宙研究機構, 特任研究員 (60731776)
|
|---|
| 研究期間 (年度) |
2015-04-01 – 2017-03-31
|
| キーワード | Galaxy Evolution / Radio Astronomy / Ultra-deep sky survey |
|---|
| 研究実績の概要 |
We have successfully produced the deepest image of the sky at radio frequencies in the history with the Jansky Very Large Array (JVLA), a radio observatory operated by the US National Radio Astronomy Observatory in New Mexico, USA. The observations are in the area of the sky called “Hubble Ultra-Deep Field” (HUDF), which harbors the most sensitive legacy observations at virtually every wavelength from X-ray to radio in existence. The effort resulted in a factor of 20x improvement in radio sensitivity over the previous works; the final image shows detailed structures of star-forming galaxies and active galactic nuclei during their peak epoch of evolution (6 - 10 billion years ago), independent of dust obscuration. We have combined our radio image with the ancillary data in the HUDF to pin down the exact location of star formation in each galaxy during these epochs, which was never before possible due to their inherent obscuring dust; the size and location of star-forming regions is the focus of the first paper being prepared. We have discovered that intense star formation occur over the wide area of galactic disks, and that star formation in galaxies with actively growing supermassive black hole are co-spatial with the location of the supermassive blackhole. The surface density of star formation were found to be so great that they will drive strong mass outflow, which will have profound implications on their evolution.
|
| 現在までの達成度 (区分) |
現在までの達成度 (区分)
1: 当初の計画以上に進展している
理由
Data for the proposed research are observations acquired with the JVLA via an observation program led by the PI. The data acquisition was completed on September 23, 2015, and were promptly analyzed using the high-performance computing facilities at Kavli IPMU. The analysis process comprise of data calibration and imaging, which was completed in January 2016. The data analysis went smoothly thanks to unrestricted access to the aforementioned computing facilities, and the only delay encountered was due to observational delays beyond our control (3 months delay in total). The first two publications are in preparation as planned for submission in early FY2016 (please refer to the future plan below). The resulting radio data help leveraged a new research program: we started a data sharing collaboration with a team who conducted the most sensitive survey in the millimeter band in the same area of the sky using the Atacama Large Millimeter Array (ALMA, led by James Dunlop; please refer to the International Joint Research section below). This was not an anticipated development, but has played a major role in amplifying the impact of our research program. The first planned paper now employs both data from JVLA and ALMA. We have also used the combined data set as a stepping stone to proposed for molecular gas observations using ALMA, as devised in the original research plan. Overall, the project has progressed better than the original plan.
|
| 今後の研究の推進方策 |
With the observation, data analysis, and object cataloging completed, we are preparing two first publications on (1) size and location of star formation in Hubble Ultra-Deep Field galaxies using JVLA and ALMA observations (submission anticipated in May 2016); (2) survey paper (submission anticipated in summer 2016). Based on our data, we have submitted two observing proposals to obtain time on (1) a Keck/MOSFIRE observations for near-IR spectroscopy to characterize ionized gas properties of our galaxies and (2) a Cycle 4 ALMA proposal to observe their molecular gas properties, the result of which will be known by summer 2016. To help interpret the properties of distant star-forming galaxies, it is necessary to construct a reference sample in the local Universe, where a broad range of physical properties can be measured precisely. The PI therefore proposed, successfully, to obtain JVLA observations for a large number of MaNGA galaxies in collaboration with Kevin Bundy (also at Kavli IPMU). The pilot observations was completed and the main observations are starting in May - September 2016. The data will be analyzed in the same fashion as the aforementioned ultra-deep data at IPMU, and will result in a separated publications in their own rights.
|
| 次年度使用額が生じた理由 |
The PI anticipated that the grant will be primarily used for publication charges in the Astrophysical Journal (3 papers anticipated, approx. USD 2,000 each), travel to collaboration and conference, and computing as originally planned. The papers outlined here are the two papers mentioned in Sec 4, and additionally the synergistic observations of JVLA and MaNGA to serve as a reference sample to interpret distant galaxies properties. Computing cost are primarily storage, due to the large volume of our data (more than 30 TB at present). Due to the slight delay (3 months) of data acquisition, the publication of the first results, utilizing the grant for page charges) is now planned for early FY2016, hence a portion of remaining funds from FY2015 are prepared for this expense.
|
| 次年度使用額の使用計画 |
The PI anticipated that the grant will be primarily used for publication charges in the Astrophysical Journal (3 papers anticipated in the short timescale, approx. USD 2,000 each), along with travel to collaboration and conference, and computing as originally planned. The three papers outlined here are the two papers from the ultra-deep program mentioned in Section 4, and additionally the synergistic observations between JVLA and MaNGA to serve as a reference sample to interpret distant galaxies properties. Computing cost are anticipated to be storage (i.e., hard disk drives), due to the large volume of our data (more than 30 TB at present).
|
