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第4回「あかり」国際会議 (2017年10月17-20日. 東京大学), 文京区, 東京, The 4th AKARI International Conference: The Cosmic Wheel and the Legacy of the AKARI archive: from galaxies and stars to planets and life (October 17-20, 2017. The University of Tokyo), Bunkyo-ku, Tokyo, Japan, At the turn of the 21st century, we enjoyed a renaissance of far-IR astronomy because of the coming of the next generation of far-IR satellites, Spitzer, AKARI, and Herschel. Here, we quickly summarize outcomes of the stellar evolution research done using far-IR data taken these space telescopes, especially those that are based on imaging of the evolved star circumstellar shells. Also, we briefly outline what to be done using the next generation of far-IR telescopes., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1730026025, レポート番号: JAXA-SP-17-009E

第4回「あかり」国際会議 (2017年10月17-20日. 東京大学), 文京区, 東京, The 4th AKARI International Conference: The Cosmic Wheel and the Legacy of the AKARI archive: from galaxies and stars to planets and life (October 17-20, 2017. The University of Tokyo), Bunkyo-ku, Tokyo, Japan, We introduce a general-purpose surface brightness correction method for compact extended sources imaged in the slow-scan pointed-observation mode of the Far-Infrared Surveyor (FIS) aboard the AKARI infrared astronomical satellite. Our method recovers correct surface brightness maps by rescaling archived raw FIS maps using the surface-brightness-dependent inverse FIS response function. The flux of a target source is then automatically corrected for as the simple sum of surface brightnesses within the adopted target perimeter (i.e., standard contour photometry). This correction method is contrasted with the previous aperture photometry method for point sources, which directly corrects for the target flux with a flux-dependent scaling law. The new surface brightness correction method is applicable to objects of any shape from unresolved point sources to resolved extended objects, as long as the target is not deemed diffuse, i.e., the total extent of the target source does not exceed much more than a single FIS scan width of about 10 min. The new correction method takes advantage of the well-defined shape (i.e., the scale-invariance) of the point spread function, which enables us to adopt a power-law FIS response function. We analyze the point source photometric calibrator data using the FIS AKARI Slow-Scan Tool and constrain the parameters of the adopted power-law FIS response function. We conclude that the photometric accuracy of the new correction method is better than 10% error based on comparisons with the expected fluxes of the photometric calibrators, and that resulting fluxes without the present correction method can lead to differences more than a factor of two., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1730026053, レポート番号: JAXA-SP-17-009E

第4回「あかり」国際会議 (2017年10月17-20日. 東京大学), 文京区, 東京, The 4th AKARI International Conference: The Cosmic Wheel and the Legacy of the AKARI archive: from galaxies and stars to planets and life (October 17-20, 2017. The University of Tokyo), Bunkyo-ku, Tokyo, Japan, As one of the follow-up studies of the Herschel Planetary Nebula Survey (HerPlaNS; Ueta et al. 2014), we focus on a Crich bipolar planetary nebula (PN) NGC6781 to characterize the dusty nebula and the central star based on our own Herschel data and the rich archival spectroscopic/photometric imaging data in wavelengths from UV to radio wavelength. With CLOUDY, we construct a comprehensive photoionization model of NGC6781 ever made incorporating data from UV to radio. We reproduce the observed spectral energy distribution (SED) and all the atomic gas, H2, CO, and OH molecular line fluxes. We estimate the total gas mass to be 0.41 solar mass by our CLOUDY modeling. A significant fraction of this total mass (about 70 %) is found to exist in the photodissociation region (PDR), demonstrating the critical importance of the PDR in PNe that are generally recognized as the hallmark of ionized/H+ regions. From our detailed multiwavelength analysis of NGC6781, we emphasise that characterizing PDRs and estimating warmcold gas/dust masses in any astronomical objects would be very important for fully understanding stellar evolution and material recycling in galaxies. Dataset provided by FarIR AKARI and Herschel have a critical role to investigate PDRs in PNe., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1730026055, レポート番号: JAXA-SP-17-009E

SPICA Science Conference from Exoplanets to Distant Galaxies: SPICA's New Window on the Cool Universe (June 18-21, 2013. Ito Hall, the University of Tokyo), Bunkyou-ku, Tokyo, Japan, We present the preliminary results of the flux calibration for extended sources observed with the Far-Infrared Surveyor (FIS) onboard the AKARI satellite. The circumstellar shells of evolved stars (particularly of AGB and post-AGB stars) retain the fossil record of their mass loss in the form of dust/gas density distributions and these shells have the potential to verify/constrain many theoretical aspects of stellar evolution and mass loss. Hence, it is critical to have an accurate surface brightness and flux calibration. The FIS has four photometric bands between 50-180 μm with two types of Ge:Ga array detectors. The Ge:Ga array is long known to have a slow transient response and FIS has already been characterized for point sources. To calibrate for extended sources, we used a method in which photometry is done in a contour aperture of the 3σ detection threshold above the background to encompass more than the PSF core. We show that the revised slow transient corrections for the short wavelength band have a similar functional form as for the point source corrections, whereas for the long wavelength band two distinct functional forms dependent on the source brightness., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1730027055, レポート番号: JAXA-SP-17-010E

SPICA Science Conference from Exoplanets to Distant Galaxies: SPICA's New Window on the Cool Universe (June 18-21, 2013. Ito Hall, the University of Tokyo), Bunkyou-ku, Tokyo, Japan, Herschel Planetary Nebula Survey (HerPlaNS) is a far-IR imaging and spectroscopic survey of planetary nebulae, performed with the Herschel Space Observatory, aiming at understanding the energetics and shaping history of the circumstellar nebulae. Below we briefly demonstrate the breadth and depth of the HerPlaNS data set using one of the targets, NGC 6781, as an example, and explore expectations in the era of SPICA, the next-generation far-IR mission., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1730027040, レポート番号: JAXA-SP-17-010E

第4回「あかり」国際会議 (2017年10月17-20日. 東京大学), 文京区, 東京, The 4th AKARI International Conference: The Cosmic Wheel and the Legacy of the AKARI archive: from galaxies and stars to planets and life (October 17-20, 2017. The University of Tokyo), Bunkyo-ku, Tokyo, Japan, The AKARI Infrared Astronomical Satellite produced the far-IR all-sky survey (AFASS) maps at roughly arc-minute spatial resolution with its Far-IR Surveyor (FIS) instrument. The AFASS maps enable us to probe the whole sky for sources having far-IR surface brightnesses higher than a few to a couple of dozen MJy sr(exp -1). While the AFASS maps are absolutely calibrated against large-scale diffuse background emission, it is uncertain whether or not an additional flux correction is necessary for small-scale compact and point sources. Here, we verify that point-source photometry reproduces fluxes in the AKARI-FIS bright source catalogue (BSC) as long as the aperture correction based on the empirical point-spread-function profiles of the AFASS maps is applied. This means that far-IR photometry of any source can be done from the AFASS maps by summing surface brightness pixel values within an appropriately-defined perimeter of the target source., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1730026054, レポート番号: JAXA-SP-17-009E

SPICA Science Conference from Exoplanets to Distant Galaxies: SPICA's New Window on the Cool Universe (June 18-21, 2013. Ito Hall, the University of Tokyo), Bunkyou-ku, Tokyo, Japan, Results of infrared photometries and dust shell modeling of a peculiar object WISE J180956.27-330500.2 are presented. The object has shown a significant time variation of its SED in the last 30 years. The variation is understood as a formation and expansion of massive dust shell since late 1990’s. The object was suspected to be a red star in the optical wavelengths before the mass ejection, which allows us to hypothesize that the object is possibly the first example of the AGB star just experiencing an episodic mass loss after a thermal pulse. Observation of this object with SPICA after some 10 years from now will bring us an important clue to understand the stellar evolution and mass loss, as well as the chemistry in the thick circumstellar envelopes., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1730027058, レポート番号: JAXA-SP-17-010E