A survey of T Tauri stars with AKARI toward the Taurus-Auriga region

Aims: We search new T Tauri star (TTS) candidates with the mid-infrared (MIR) part of the AKARI All-Sky Survey at 9 and 18 um wavelengths. Methods: We used the point source catalogue (PSC), obtained by the Infrared Camera (IRC) on board AKARI. We combined the 2MASS PSC and the 3rd version of the USNO CCD Astrograph Catalogue (UCAC) with the AKARI IRC-PSC, and surveyed 517 known TTSs over a 1800-square-degree part of the Taurus-Auriga region to find criteria to extract TTSs. We considered asymptotic giant branch (AGB) stars, post-AGB stars, Planetary Nebulae (PNe), and galaxies, which have similar MIR colours, to separate TTSs from these sources. Results: Of the 517 known TTSs, we detected 133 sources with AKARI. Based on the colour-colour and colour-magnitude diagrams made from the AKARI, 2MASS, and UCAC surveys, we propose the criteria to extract TTS candidates from the AKARI All-Sky data. On the basis of our criteria, we selected 176/14725 AKARI sources as TTS candidates which are located around the Taurus-Auriga region. Comparing these sources with SIMBAD, there are 148 previously identified sources including 115 Young Stellar Objects (YSOs), and 28 unidentified sources. Conclusions: Based on SIMBAD identifications, we take the TTS-identification probability using our criteria to be ~75 %. We find 28 TTS candidates, of which we expect 21 to be confirmed once follow-up observations can be obtained. Although the probability of ~75 % is not so high, it is affected by the completeness of the SIMBAD database, and we can search for TTSs over the whole sky, over all star forming regions.Comment: 12 pages, 9 figures, accepted for publication in A&

Resovist-Enhanced MRI for Preoperative Assessment of Colorectal Hepatic Metastases: A Case of Multiple Bile Duct Hamartomas Associated with Colon Cancer

Extensive preoperative assessment of hepatic metastases is required in colon cancer patients. We report a case in whom the preoperative investigation by ultrasound scan and contrast-enhanced computed tomography revealed numerous cystic lesions of the liver, suspicious of von Meyenburg complex. Magnetic resonance and magnetic resonance cholangiographic images demonstrated typical features of von Meyenburg complex. Further Resovist-enhanced magnetic resonance imaging detected two hemangiomas in addition to the multiple cystic lesions. So-called Kupffer cell imaging strongly helped the detection of these hemangiomas, and a combination of various magnetic resonance pulse sequences was of great value for the differential diagnosis of cystic lesions and hemangiomas. In cases in whom conventional imaging studies fail to give a definite diagnosis, such as in the present case, superparamagnetic iron oxide-enhanced magnetic resonance imaging is meaningful for adequate preoperative staging

Prevalence and factors related to hot flashes and night sweats in postpartum women in Japan

Hot flashes and night sweats commonly occur during menopausal transition period due to estrogen deficiency, but these conditions can also occur during postpartum period in which there are marked hormonal fluctuations. This study determined the prevalence and examined factors related to hot flashes and night sweats among the Japanese women in the postpartum period. The design of this study was a longitudinal investigation and the population of the postpartum women recruited was 229. A self-administered questionnaire that adapted Edinburgh Postnatal Depression Scale (EPDS) of measurement was used to collect data at 3 days postpartum, 2 weeks postpartum and one month postpartum. There was a significant association between transient night sweats and anxiety regarding family finances. Women who complained of hot flashes was 22.8% at 3 days postpartum and it decreased thereafter, while women who complained of night sweats were 58.6% at 3 days postpartum, 33.1% at 2 weeks postpartum and 15.2% at one month postpartum. In conclusion, hot flashes and night sweats among Japanese women in the postpartum period was associated with psychological and social factors

産後6か月間におけるうつ・不安症状の経過と新生児と関わる時の感情との関連

Background: Depressive symptoms and anxiety symptoms during the postpartum period affect physical health and child rearing and that these effects are important social issues. Objective: The aims of this study were to clarify the differences in the transition of depressive symptoms and anxiety symptoms according to parity during a 6-month postpartum period and to clarify the differences in associations of depressive symptoms and anxiety symptoms with feelings for involvement with newborn infants in primiparous and multiparous postpartum women. Methods: The design of this study was a longitudinal investigation. This study was conducted from February 2017 to July 2018 in Japan. By using self-administered questionnaires that included questions on psychological symptoms in a standard climacteric scale and questions on feelings for involvement with newborn infants, we collected data at 3 days postpartum, 2 weeks postpartum, one month postpartum, 3 months postpartum and 6 months postpartum. Results: Responses to all of the questionnaires were obtained from 121 (52.8%) of 229 women. The score for depressive symptoms in primiparous women was significantly higher than that in multiparous women at 3 days postpartum. Depressive symptoms and anxiety symptoms showed peaks at 2 weeks postpartum in both primiparous women and multiparous women, but depressive symptoms reoccurred from 3 months postpartum to 6 months postpartum in primiparous women and anxiety symptoms reoccurred from one month to 3 months postpartum in multiparous women. Depressive symptoms and anxiety symptoms were associated with negative feelings for involvement with newborn infants and with mother’s sleeping time. Conclusion: Changes in depressive symptoms and anxiety symptoms were different in primiparous women and multiparous women during a 6-month postpartum period. In addition, depressive symptoms and anxiety symptoms were associated with negative feelings for involvement with newborn infants and with sleeping time in postpartum women

Detection of an H-alpha Emission Line on a Quasar, RX J1759.4+6638, at z=4.3 with AKARI

We report the detection of an H-alpha emission line in the low resolution spectrum of a quasar, RX J1759.4+6638, at a redshift of 4.3 with the InfraRed Camera (IRC) onboard the AKARI. This is the first spectroscopic detection of an H-alpha emission line in a quasar beyond z=4. The overall spectral energy distribution (SED) of RX J1759.4+6638 in the near- and mid-infrared wavelengths agrees with a median SED of the nearby quasars and the flux ratio of F(Ly-alpha)/F(H-alpha) is consistent with those of previous reports for lower-redshift quasars.Comment: 9pages, 3 figures, Publications of the Astronomical Society of Japan, in pres

Near-infrared and Mid-infrared Spectroscopy with the Infrared Camera (IRC) for AKARI

The Infrared Camera (IRC) is one of the two instruments on board the AKARI satellite. In addition to deep imaging from 1.8-26.5um for the pointed observation mode of the AKARI, it has a spectroscopic capability in its spectral range. By replacing the imaging filters by transmission-type dispersers on the filter wheels, it provides low-resolution (lambda/d_lambda ~ 20-120) spectroscopy with slits or in a wide imaging field-of-view (approximately 10'X10'). The IRC spectroscopic mode is unique in space infrared missions in that it has the capability to perform sensitive wide-field spectroscopic surveys in the near- and mid-infrared wavelength ranges. This paper describes specifications of the IRC spectrograph and its in-orbit performance.Comment: 13 pages, 7 figures, accepted for publication on PAS

Hot debris dust around HD 106797

Photometry of the A0 V main-sequence star HD 106797 with AKARI and Gemini/T-ReCS is used to detect excess emission over the expected stellar photospheric emission between 10 and 20 micron, which is best attributed to hot circumstellar debris dust surrounding the star. The temperature of the debris dust is derived as Td ~ 190 K by assuming that the excess emission is approximated by a single temperature blackbody. The derived temperature suggests that the inner radius of the debris disk is ~ 14 AU. The fractional luminosity of the debris disk is 1000 times brighter than that of our own zodiacal cloud. The existence of such a large amount of hot dust around HD 106797 cannot be accounted for by a simple model of the steady state evolution of a debris disk due to collisions, and it is likely that transient events play a significant role. Our data also show a narrow spectral feature between 11 and 12 micron attributable to crystalline silicates, suggesting that dust heating has occurred during the formation and evolution of the debris disk of HD 106797.Comment: Accepted to ApJ Letters, 8 pages, 2 figure