bluuebunny/crossref_metadata_2025 huggingface dataset:
Abundances of Volatile Elements in Post-AGB Candidates
Authors: Takeda Yoichi , Taguchi Hikaru , Yoshioka Kazuo , Hashimoto Osamu , Aikawa Toshiki , Kawanomoto Satoshi
Published: March 2014

A detailed non-LTE study on the abundances of C, N, O, S, and Zn was carried out for five F–G supergiants of suspected post-AGB candidates with IR excesses (HD 112374, HD 148743, HD 161796, HD 163506, and HD 187203), since these volatile elements can provide the key to inferring the original metallicity as well as an evolution-induced change due to mixing, given that they are free from depletion caused by dust–gas separation. The extent of separation-induced depletion in Fe, estimated by comparing with Zn, turned out to be rather moderate ($\lesssim$ several tenths dex). The characteristics of the C, N, and O abundances do not appear to be very different from the case of the first dredge-up in normal supergiants (decreased C and enriched N due to the first dredge-up); thus, the specific anomaly related to an advanced post-AGB stage so far reported (such as elevated C and O) could not be clearly confirmed.
A Bright Transient X-Ray Source Near the Galactic Center Found in Archival Ginga Data from 1987
Authors: Yamauchi Shigeo , Nakagawa Yoshio , Sudoh Keisuke , Kitamoto Shunji
Published: March 2014

A bright transient X-ray source was detected in the direction of the galactic center with Ginga in 1987 March. A sky position was determined from both data obtained with the All Sky Monitor (ASM) and cross-scan data obtained with the Large Area proportional Counters (LAC). Based on the sky position derived from both the ASM and the LAC data, this source was designated as GS 1741$-$288. At the beginning of the Ginga observations, GS 1741$-$288 was in the active state: its energy flux in the 2–10 keV energy band was $\sim$10$^{-8}$ergs$^{-1}$cm$^{-2}$. The ASM light curve showed that the intensity gradually decayed with an e-folding time of $190\pm9$d. No remarkable feature, such as periodic or quasi-periodic oscillations was found. The spectral and temporal properties suggest that GS 1741$-$288 is likely to be a low-mass X-ray binary system containing a weakly magnetized neutron star. Possible identification of the source is also discussed.
Subaru Near-Infrared Multicolor Images of Class II Young Stellar Object, RNO 91
Authors: Mayama Satoshi , Tamura Motohide , Hayashi Masahiko , Itoh Yoichi , Ishii Miki , Fukagawa Misato , Hayashi Saeko S. , Oasa Yumiko , Kudo Tomoyuki
Published: March 2014

We conducted subarcsecond near-infrared imaging observations of RNO 91 with CIAO (Coronagraphic Imager with Adaptive Optics) mounted on the 8.2 m Subaru telescope. We present our JHK band data along with optical images, which when considered together reveal a complex circumstellar structure. We examined the colors of associated nebulae and compared the geometry of the outflow/disk system suggested by our data with that already proposed on the basis of previous studies. Our K-band image shows bright circumstellar nebulosity detected within $\sim$2$^{\prime\prime}$ around the central source, while it is less conspicuous at shorter wavelengths. PA and the size of this red color nebulosity agree with those of the previously detected polarization disk. Agreements among these data indicate that this bright nebulosity region, which follows the reddening law, might be attributed to a disklike structure. At $J$ and optical wavelengths, several blue knotlike structures are detected around and beyond the bright circumstellar nebulosity. We suggest that these knotty reflection nebulae may represent disintegrating fragments of an infalling envelope. The three-color composite image has the appearance of arc-shaped nebulosity. We interpret these structures as being roots of a bipolar cavity opening toward the northeast and the southwest. The complex distribution of reflection nebulosity seen around RNO 91 appears to confirm the interpretation that this source is an object dispersing its molecular envelope while transitioning from protostar to T Tauri star.
Water Maser and Ammonia Survey toward IRAS Sources in the Galaxy I. H$_{2}$O Maser Data
Authors: Sunada Kazuyoshi , Nakazato Takeshi , Ikeda Norio , Hongo Satoshi , Kitamura Yoshimi , Yang Ji
Published: March 2014

We present H $_{2}$ O maser data from a survey toward IRAS sources in the Galaxy with the Nobeyama 45 m telescope. This survey had a 1$\sigma$ noise level as small as 0.24 Jy, resulting in one of the most sensitive water-maser surveys. The maximum distance of the masers to be detected by our survey is estimated to be 3 kpc for sources with $F_{\nu, \mathrm{1\,kpc}} <$ 10 Jy and 10 kpc for those with 10 Jy $\le F_{\nu, \mathrm{1\,kpc}} <$ 100 Jy, where $F_{\nu, \mathrm{1\,kpc}}$ is the maser flux density converted at a distance of 1 kpc. For strong masers with $F_{\nu, \mathrm{1\,kpc}} \ge$ 100 Jy, our survey could detect all sources in the Galaxy. We carried out a total of 2229 observations toward 1563 sources and detected water-maser emission toward 222 sources. Our survey newly found masers from 75 of the 222 sources. The maser spectra of the new sources are shown in addition to the line parameters of all the detected sources. Furthermore, we discovered an extremely high-velocity component with $V_\mathrm{LSR} = -146$kms$^{-1}$ toward a well-known source, NGC 7538 IRS 11. For the three sources of NGC 1333 IRAS 4A/B, IRAS 05329$-$0512, and 06053$-$0622, we succeeded to spatially separate multiple-velocity components.
Radiation Testing of Consumer High-Speed LSI Chips for the Next Space VLBI Mission
Authors: Wajima Kiyoaki , Kawaguchi Noriyuki , Murata Yasuhiro , Hirabayashi Hisashi
Published: March 2014

We carried out two types of radiation testing of high-speed LSI chips to test their suitability for use in wideband observations by the Japanese next space VLBI mission, VSOP-2. In a total ionization-dose experiment we monitored autocorrelation spectra, which were taken with irradiated LSI chips and the source current at intervals of up to 1000 hr from the ionization dose, but could not detect any change of these features for chips irradiated at the dose rates expected in the VSOP-2 mission. In a single event effect experiment, we monitored the cross-correlation phase and the power spectra between data from radiated and nonradiated devices, and the source current during the irradiation of heavy ions. We observed a few tens of single event upsets as discrete delay jumps for each LSI. We estimated the occurrence rate of single events in space to be between once every few days and once a month. No single event latch-up was seen in any of LSIs. These results show that the tested LSIs have sufficiently high tolerance for the environment for space VLBI observations.
Suzaku Observation of Diffuse X-Ray Emission from the Carina Nebula
Authors: Hamaguchi Kenji , Petre Robert , Matsumoto Hironori , Tsujimoto Masahiro , Holt Stephen S. , Ezoe Yuichiro , Ozawa Hideki , Tsuboi Yohko , Soong Yang , Kitamoto Shunji , Sekiguchi Akiko , Kokubun Motohide
Published: March 2014

We studied extended X-ray emission from the Carina Nebula taken with the Suzaku CCD camera XIS on 2005 August 29. The X-ray morphology, plasma temperature, and absorption to the plasma are consistent with the earlier Einstein results. The Suzaku spectra newly revealed emission lines from various species, including oxygen, but not from nitrogen. This result restricts the $\mathrm{N/O}$ ratio to be significantly low, compared with evolved massive stellar winds, suggesting that the diffuse emission originated in an old supernova remnant or a super shell produced by multiple supernova remnants. The X-ray spectra from the north and south of $\eta$ Car showed distinct differences between 0.3–2 keV. The south spectrum shows strong L-shell lines of iron ions and K-shell lines of silicon ions, while the north spectrum shows them weak in intensity. This means that the silicon and iron abundances are a factor of 2–4 higher in the south region than in the north region. The abundance variation may be produced by an SNR ejecta, or related to dust formation around the star-forming core.
Discovery of a New X-Ray Transient Source in the Scutum Region with Suzaku
Authors: Yamauchi Shigeo , Ebisawa Ken , Bamba Aya , Ishida Manabu , Iwasawa Kazushi , Tanaka Yasuo , Kokubun Motohide , Koyama Katsuji , Takahashi Hiromitsu , Tsuboi Yohko
Published: March 2014

During an observation of the Galactic plane in the Scutum region with the Suzaku satellite, we discovered a new X-ray transient source, designated Suzaku J1844$-$0404. Compared with previous Chandra observations of the same field, four Chandra X-ray sources exist within the current positional uncertainty of Suzaku J1844$-$0404. A firm identification is not possible. From the beginning of the observation, the X-ray intensity was significant at $\sim 5 \times 10^{-14} \,\mathrm{erg} \,\mathrm{s}^{-1} \,\mathrm{cm}^{-2}$ (2–10 keV), which may be a possible precursor. Later, the source exhibited a flare with a peak flux of $\sim 10^{-12} \,\mathrm{erg} \,\mathrm{s}^{-1} \,\mathrm{cm}^{-2}$ (2–10 keV). A strong and narrow emission line at $\sim 6.66 \,\mathrm{keV}$ was observed during the flare, most likely the He-like Fe line. The spectrum in 1–10 keV is consistent with a heavily absorbed ($N_{\mathrm{H}} \sim 3 \times 10^{22} \,\mathrm{H} \,\mathrm{cm}^{-2}$) thin thermal emission with $kT$ as high as $\sim 7 \,\mathrm{keV}$. A single short flare, as observed, is rather unlikely for a cataclysmic variable. The source is probably an active binary star or a young stellar object.
Suzaku Spectroscopic Study of Hard X-Ray Emission in the Arches Cluster
Authors: Tsujimoto Masahiro , Hyodo Yoshiaki , Koyama Katsuji
Published: March 2014

We present the results of a Suzaku study of the Arches cluster in the Galactic center region. A high signal-to-noise ratio spectrum in the 3–12 keV band was obtained with the X-ray Imaging Spectrometer (XIS) onboard the Suzaku observatory. We found that the spectrum consists of a thermal plasma, a hard power-law tail, and two Gaussian line components. The plasma component with a temperature of $\sim 2.2 \,\mathrm{keV}$ is established from the presence of Ca XIX and Fe XXV $\mathrm{K}\alpha$ lines as well as absence of the Fe XXVI $\mathrm{K}\alpha$ line. The two Gaussian lines represent the $\mathrm{K}\alpha$ and $\mathrm{K}\beta$ lines from iron at lower ionization stages at $\sim 6.4$ and $\sim 7.1 \,\mathrm{keV}$. Both the line centers and the intensity ratio of these two lines are consistent with neutral iron. The hard power-law tail with a photon index of $\sim 0.7$ was found to have no pronounced iron K edge feature. Compared with the published Chandra spectra constructed separately for point-like and diffuse emission, we conclude that the thermal component is from an ensemble of point-like sources plus thermal diffuse emission concentrated at the cluster center, while the Gaussian and the hard tail components are from non-thermal diffuse emission extended in a larger scale. In band-limited images of the XIS field, the distribution of the 7.5–10.0 keV emission resembles that of the 6.4 keV emission, including local excess at the Arches cluster. This strongly suggests that the power-law emission is related to the 6.4 and 7.1 keV lines in the underlying physics. We discuss two ideas to explain both the hard continuum and the lines: (1) X-ray photoionization that produces fluorescence lines and the Thomson scattering continuum and (2) non-thermal electron impact ionization of iron atoms and bremsstrahlung continuum. However, whichever scenario is adopted, the photon or particle flux from the Arches cluster is too low to account for the observed lines and continuum intensity.
Hard X-Ray Detector (HXD) on Board Suzaku
Authors: Takahashi Tadayuki , Abe Keiichi , Endo Manabu , Endo Yasuhiko , Ezoe Yuuichiro , Fukazawa Yasushi , Hamaya Masahito , Hirakuri Shinya , Hong Soojing , Horii Michihiro , Inoue Hokuto , Isobe Naoki , Itoh Takeshi , Iyomoto Naoko , Kamae Tuneyoshi , Kasama Daisuke , Kataoka Jun , Kato Hiroshi , Kawaharada Madoka , Kawano Naomi , Kawashima Kengo , Kawasoe Satoshi , Kishishita Tetsuichi , Kitaguchi Takao , Kobayashi Yoshihito , Kokubun Motohide , Kotoku Jun’ichi , Kouda Manabu , Kubota Aya , Kuroda Yoshikatsu , Madejski Greg , Makishima Kazuo , Masukawa Kazunori , Matsumoto Yukari , Mitani Takefumi , Miyawaki Ryohei , Mizuno Tsunefumi , Mori Kunishiro , Mori Masanori , Murashima Mio , Murakami Toshio , Nakazawa Kazuhiro , Niko Hisako , Nomachi Masaharu , Okada Yuu , Ohno Masanori , Oonuki Kousuke , Ota Naomi , Ozawa Hideki , Sato Goro , Shinoda Shingo , Sugiho Masahiko , Suzuki Masaya , Taguchi Koji , Takahashi Hiromitsu , Takahashi Isao , Takeda Shin’ichiro , Tamura Ken-ichi , Tamura Takayuki , Tanaka Takaaki , Tanihata Chiharu , Tashiro Makoto , Terada Yukikatsu , Tominaga Shin’ya , Uchiyama Yasunobu , Watanabe Shin , Yamaoka Kazutaka , Yanagida Takayuki , Yonetoku Daisuke
Published: March 2014

The Hard X-ray Detector (HXD) on board Suzaku covers a wide energy range from 10 keV to 600 keV by the combination of silicon PIN diodes and GSO scintillators. The HXD is designed to achieve an extremely low in-orbit background based on a combination of new techniques, including the concept of a well-type active shield counter. With an effective area of $142 \,\mathrm{cm}^{2}$ at 20 keV and $273 \,\mathrm{cm}^{2}$ at 150 keV, the background level at sea level reached $\sim 1 \times 10^{-5} \,\mathrm{cts} \,\mathrm{s}^{-1} \,\mathrm{cm}^{-2} \,\mathrm{keV}^{-1}$ at 30 keV for the PIN diodes, and $\sim 2 \times 10^{-5} \,\mathrm{cts} \,\mathrm{s}^{-1} \,\mathrm{cm}^{-2} \,\mathrm{keV}^{-1}$ at 100 keV, and $\sim 7 \times 10^{-6} \,\mathrm{cts} \,\mathrm{s}^{-1} \,\mathrm{cm}^{-2} \,\mathrm{keV}^{-1}$ at 200 keV for the phoswich counter. Tight active shielding of the HXD results in a large array of guard counters surrounding the main detector parts. These anti-coincidence counters, made of $\sim 4 \,\mathrm{cm}$ thick BGO crystals, have a large effective area for sub-MeV to MeV $\gamma$-rays. They work as an excellent $\gamma$-ray burst monitor with limited angular resolution ($\sim 5^{\circ}$). The on-board signal-processing system and the data transmitted to the ground are also described.
Swift and Suzaku Observations of the X-Ray Afterglow from the GRB 060105
Authors: Tashiro Makoto S. , Abe Keiichi , Angelini Lorella , Barthelmy Scott , Gehrels Neil , Ishikawa Nobuyuki , Kaluzienski Louis J. , Kawai Nobuyuki , Kelley Richard L. , Kinugasa Kenzo , Kodaira Hironobu , Kohmura Takayoshi , Kubota Kaori , Maeda Yoshitomo , Maeno Shouta , Murakami Hiroshi , Murakami Toshio , Nakagawa Yujin E. , Nakazawa Kazuhiro , Nousek John , Okuno Shin’ya , Onda Kaori , Reeves James N. , Ricker George , Sato Goro , Sonoda Eri , Suzuki Motoko , Takahashi Tadayuki , Tamagawa Toru , Torii Ken’ichi , Ueda Yoshihiro , Urata Yuji , Yamaoka Kazutaka , Yamauchi Makoto , Yonetoku Daisuke , Yoshida Atsumasa , Yoshinari Satoru
Published: March 2014

Results are presented of early X-ray afterglow observations of GRB 060105 by Swift and Suzaku. The bright, long gamma-ray burst GRB 060105 triggered the Swift Burst Alert Telescope at 06:49:28 on 2006 January 5 ($T_0$). The Suzaku team commenced a pre-planned target of opportunity observation at 19 ks (5.3 hr) after the Swift trigger. The X-ray flux faded during observations from $6.8 \times 10^{-9} \,\mathrm{erg} \,\mathrm{s}^{-1} \,\mathrm{cm}^{-2}$ (at $T_0 + 87 \,\mathrm{s}$ with the Swift/XRT) to $1.5 \times 10^{-13} \,\mathrm{erg} \,\mathrm{s}^{-1} \,\mathrm{cm}^{-2}$ [at $T_0 + 94 \hbox{}{--} 101 \,\mathrm{ks}$ with the Suzaku X-ray Imaging Spectrometer (XIS)] in the 2–10 keV energy band. Following prompt emission and successive very steep decay, a shallow decay was observed from $T_0 + 187 \,\mathrm{s}$ to $T_0 + 1287 \,\mathrm{s}$. After an observation gap during $T_0 + (1.5 \hbox{}{--} 3) \;\mathrm{ks}$, an extremely early steep decay was observed in $T_0 + (4 \hbox{}{--} 30) \;\mathrm{ks}$. The lightcurve flattened again at $T_0 + 30 \,\mathrm{ks}$, and another steep decay followed from $T_0 + 50 \,\mathrm{ks}$ to the end of observations. Both steep decays exhibited decay indices of 2.3–2.4. This very early break, if it is a jet break, is the earliest case among X-ray afterglow observations, suggesting a very narrow jet whose opening angle is well below $1^\circ$. The unique Suzaku/XIS data allow us to set very tight upper limits on line emission or absorption in this GRB. For the reported pseudo-redshift of $z = 4.0 \pm 1.3$ the upper limit on the iron line equivalent width is 50 eV.
The X-Ray Telescope onboard Suzaku
Authors: Serlemitsos Peter J. , Soong Yang , Chan Kai-Wing , Okajima Takashi , Lehan John P. , Maeda Yoshitomo , Itoh Kei , Mori Hideyuki , Iizuka Ryo , Itoh Akiharu , Inoue Hirohiko , Okada Shunsaku , Yokoyama Yushi , Itoh Yumi , Ebara Masatoshi , Nakamura Ryoko , Suzuki Kensuke , Ishida Manabu , Hayakawa Akira , Inoue Chiaki , Okuma Satoshi , Kubota Ren , Suzuki Masaki , Osawa Takeyuki , Yamashita Koujun , Kunieda Hideyo , Tawara Yuzuru , Ogasaka Yasushi , Furuzawa Akihiro , Tamura Keisuke , Shibata Ryo , Haba Yoshito , Naitou Masataka , Misaki Kazutami
Published: March 2014

We present the design parameters, production process, and in-flight performance of the X-ray telescope (XRT) onboard Suzaku. The imaging capability is significantly improved over the ASCA XRT, which had half-power diameters of ${3\rlap {.}{}^{\mathrm {\prime }}6}$, to ${1\rlap {.}{}^{\mathrm {\prime }}8}$–${2\rlap {.}{}^{\mathrm {\prime }}3}$ for all four XRT-I modules. The optical axes are found to be distributed within a radius of ${1\rlap {.}{}^{\mathrm {\prime }}3}$, which makes the observation efficiency of all the XRTs more than 97% at the XIS-default observing position. The vignetting over the XIS field of view predicted via ray-tracing coincides with that measured for observations of the Crab Nebula to within $\sim 10\%$. Contemporaneous fits of a power law to all of the XIS spectra of the Crab Nebula taken at the two standard observing positions (XIS/HXD-default positions) gives a flux consistent with that obtained by Toor and Seward (1974, AJ, 79, 995) to within $\sim 2\%$. The pre-collimator on the top of each XRT module successfully reduces the intensity of the stray light from the $20'$ and $50'$-off directions down to the level of pre-flight expectations.
Flight Performance of the AKARI Cryogenic System
Authors: Nakagawa Takao , Enya Keigo , Hirabayashi Masayuki , Kaneda Hidehiro , Kii Tsuneo , Kimura Yoshiyuki , Matsumoto Toshio , Murakami Hiroshi , Murakami Masahide , Narasaki Katsuhiro , Narita Masanao , Ohnishi Akira , Tsunematsu Shoji , Yoshida Seiji
Published: March 2014

We describe the flight performance of the cryogenic system of the infrared astronomical satellite AKARI, which was successfully launched on 2006 February 21 (UT). AKARI carries a 68.5 cm telescope together with two focal-plane instruments, Infrared Cameras and Far Infrared Surveyor, all of which are cooled down to cryogenic temperature to achieve superior sensitivity. AKARI has a unique cryogenic system, which consists of cryogen (liquid helium) and mechanical coolers (2-stage Stirling coolers). With the help of mechanical coolers, 179 L (26.0 kg) of super-fluid liquid helium can keep the instruments cryogenically cooled for more than 500 days. The on-orbit performance of the AKARI cryogenics is consistent with the design and a pre-flight test, and the boil-off gas flow rate is as small as 0.32 mg s$^{-1}$. We observed an increase in the major axis of the AKARI orbit, which can be explained by thrust due to the thermal pressure of vented helium gas.
The Far-Infrared Surveyor (FIS) for AKARI
Authors: Kawada Mitsunobu , Baba Hajime , Barthel Peter D. , Clements David , Cohen Martin , Doi Yasuo , Figueredo Elysandra , Fujiwara Mikio , Goto Tomotsugu , Hasegawa Sunao , Hibi Yasunori , Hirao Takanori , Hiromoto Norihisa , Jeong Woong-Seob , Kaneda Hidehiro , Kawai Toshihide , Kawamura Akiko , Kester Do , Kii Tsuneo , Kobayashi Hisato , Kwon Suk Minn , Lee Hyung Mok , Makiuti Sin’itirou , Matsuo Hiroshi , Matsuura Shuji , MÜller Thomas G. , Murakami Noriko , Nagata Hirohisa , Nakagawa Takao , Narita Masanao , Noda Manabu , Oh Sang Hoon , Okada Yoko , Okuda Haruyuki , Oliver Sebastian , Ootsubo Takafumi , Pak Soojong , Park Yong-Sun , Pearson Chris P. , Rowan-Robinson Michael , Saito Toshinobu , Salama Alberto , Sato Shinji , Savage Richard S. , Serjeant Stephen , Shibai Hiroshi , Shirahata Mai , Sohn Jungjoo , Suzuki Toyoaki , Takagi Toshinobu , Takahashi Hidenori , Thomson Matthew , Usui Fumihiko , Verdugo Eva , Watabe Toyoki , White Glenn J. , Wang Lingyu , Yamamura Issei , Yamauchi Chisato , Yasuda Akiko
Published: March 2014

The Far-Infrared Surveyor (FIS) is one of two focal-plane instruments on the AKARI satellite. FIS has four photometric bands at 65, 90, 140, and 160 $\mu \rm m$, and uses two kinds of array detectors. The FIS arrays and optics are designed to sweep the sky with high spatial resolution and redundancy. The actual scan width is more than eight arcminutes, and the pixel pitch matches the diffraction limit of the telescope. Derived point-spread functions (PSFs) from observations of asteroids are similar to those given by the optical model. Significant excesses, however, are clearly seen around tails of the PSFs, whose contributions are about 30% of the total power. All FIS functions are operating well in orbit, and the performance meets the laboratory characterizations, except for the two longer wavelength bands, which are not performing as well as characterized. Furthermore, the FIS has a spectroscopic capability using a Fourier transform spectrometer (FTS). Because the FTS takes advantage of the optics and detectors of the photometer, it can simultaneously make a spectral map. This paper summarizes the in-flight technical and operational performance of the FIS.
AKARI Observations of Circumstellar Dust in the Globular Clusters NGC 104 and NGC 362
Authors: Ita Yoshifusa , Tanabé Toshihiko , Matsunaga Noriyuki , Nakada Yoshikazu , Matsuura Mikako , Onaka Takashi , Matsuhara Hideo , Wada Takehiko , Fujishiro Naofumi , Ishihara Daisuke , Kataza Hirokazu , Kim Woojung , Matsumoto Toshio , Murakami Hiroshi , Ohyama Youichi , Usui Fumihiko , Oyabu Shinki , Sakon Itsuki , Takagi Toshinobu , Uemizu Kazunori , Ueno Munetaka , Watarai Hidenori
Published: March 2014

We report on preliminary results of AKARI observations of two globular clusters, NGC 104 and NGC 362. Imaging data covering areas of about 10 $\times$ 10 arcmin$^2$ centered on the two clusters were obtained with the Infrared Camera (IRC) at 2.4, 3.2, 4.1, 7.0, 9.0, 11.0, 15.0, 18.0, and 24.0 $\mu$m. We used IRC 11.0 $\mu$m to 2 MASS $K_s$ 2 $\mu$m flux-density ratio ($F_{11}$/$F_{2}$) and IRC 24.0 $\mu$m to 7.0 $\mu$m flux-density ratio ($F_{24}$/$F_{7}$) as diagnostics of circumstellar dust emission. Dust emissions are mainly detected from variable stars, obviously on the asymptotic giant branch, but some variable stars that reside below the tip of the first-ascending giant branch also show dust emissions. We found eight red sources with the $F_{24}$/$F_{7}$ ratio being greater than unity in NGC 362. Six out of the eight have no 2 MASS counterparts. However, we found no such source in NGC 104.
Spatial Distributions of Cold and Warm Interstellar Dust in M101 Resolved with AKARI/Far-Infrared Surveyor (FIS)
Authors: Suzuki Toyoaki , Kaneda Hidehiro , Nakagawa Takao , Makiuti Sin’itirou , Okada Yoko , Shibai Hiroshi , Kawada Mitsunobu , Doi Yasuo
Published: March 2014

The nearby face-on spiral galaxy M101 has been observed with the Far-Infrared Surveyor onboard AKARI. The far-infrared four-band images reveal fine spatial structures of M101, which include global spiral patterns, giant H II regions embedded in outer spiral arms, and a bar-like feature crossing the center. The spectral energy distribution of the whole galaxy shows the presence of a cold dust component (18$^{+4}_{-10}$K) in addition to a warm dust component (55$^{+9}_{-25}$K). The distribution of the cold dust is mostly concentrated near the center, and appears to be smoothly distributed over the entire extent of the galaxy, whereas the distribution of warm dust indicates some correlation with the spiral arms, and has spotty structures, such as four distinctive bright spots in the outer disk in addition to a bar-like feature near the center, tracing the CO intensity map. The star-formation activity of the giant H II regions that spatially correspond to the former bright spots is found to be significantly higher than that of the rest of the galaxy. The latter warm dust distribution implies that there are significant star-formation activities in the entire bar filled with molecular clouds. Unlike our Galaxy, M101 is a peculiar normal galaxy with extraordinary active star-forming regions.
Properties of UIR Bands in NGC6946 Based on Mid-Infrared Imaging and Spectroscopy with Infrared Camera on Board AKARI
Authors: Sakon Itsuki , Onaka Takashi , Wada Takehiko , Ohyama Youichi , Matsuhara Hideo , Kaneda Hidehiro , Ita Yoshifusa , Ohyabu Shinki , Kataza Hirokazu , Fujishiro Naofumi , Ihara Chiaki , Ishigaki Miho , Ishihara Daisuke , Kim Woojung , Okada Yoko , Takagi Toshinobu , TanabÉ Toshihiko , Uemizu Kazunori , Ueno Munetaka , Usui Fumihiko , Watarai Hidenori , Koo Bon-Chul , Serjeant Stephen , Nakagawa Takao , Matsumoto Toshio , Murakami Hiroshi
Published: March 2014

We present results on mid-infrared imaging and spectroscopic observations of the nearby late-type spiral NGC6946 with the Infrared Camera on board AKARI. Based on mid-infrared imaging with the S7 (7$\mu$m) and S11(11$\mu$m) bands, we found that the S7/S11 ratios have larger values in the arm region, containing many star-forming regions, than in the interarm. Slit spectra of an interarm and a star-forming region show a series of unidentified infrared (UIR) bands at 6.2, 7.7, 8.6, and 11.2$\mu$m. The strengths of the 6.2, 7.7, and 8.6$\mu$m bands are larger relative to the 11.2$\mu$m band in the star-forming region, than in the interarm, even if the interstellar extinction of $A_V=3$mag towards the star-forming region is taken into account. The increase in the 6.2$\mu$m and 7.7$\mu$m features relative to the 11.2$\mu$m feature is consistent with the ionization model of PAHs. The ratio of the UIR features to the plateau emission under the 7.7$\mu$m and 8.6$\mu$m features and/or the ratio of the 7.6$\mu$m/7.8$\mu$m components in the 7.7$\mu$m feature increase in the star-forming region compared to the interarm. This variation can be accounted for by the hypothesis that the photo-evaporation of PAH clusters produce small free-flying PAHs in the star-forming region. The ratios of 6.2$\mu$m/11.2$\mu$m, 7.7$\mu$m/11.2$\mu$m, and 8.6$\mu$m/11.2$\mu$m may be tools to measure the star-formation activity in remote galaxies if these ratios and their variations are well examined and established for a large sample.
Multi-Wavelength Analysis of 18$\mu $m-Selected Galaxies in the AKARI/Infrared-Camera monitor field towards the North Ecliptic Pole
Authors: Takagi Toshinobu , Matsuhara Hideo , Wada Takehiko , Oyabu Shinki , Imai Koji , Pearson Chris P. , Hanami Hitoshi , Onaka Takashi , Fujishiro Naofumi , Ishihara Daisuke , Ita Yoshifusa , Kataza Hirokazu , Kim Woojung , Matsumoto Toshio , Murakami Hiroshi , Ohyama Youichi , Sakon Itsuki , TanabÉ Toshihiko , Uemizu Kazunori , Ueno Munetaka , Watarai Hidenori , Usui Fumihiko , Lee Hyung Mok , Im Myungshin , Serjeant Stephen , Savage Richard S. , Tange Tsutomu , Nakagawa Takao
Published: March 2014

We present an initial analysis of AKARI 18$\mu $m-selected galaxies using all 9 photometric bands at 2–24$\mu $m available in the Infrared Camera (IRC), in order to demonstrate new capabilities of AKARI cosmological surveys with this unprecedented wavelength coverage at mid-infrared (MIR) bands. We detected 72 sources at 18$\mu $m in an area of 50.2 arcmin$^2$ in the AKARI/IRC monitor field towards the North Ecliptic Pole (NEP). From this sample, 25 galaxies with probable redshifts of $z \gtrsim$ 0.5 were selected with a single colour cut (N2$-$N3$\gt$ 0.1) for a detailed spectral energy distribution (SED) analysis with ground-based $BVRi'z'JK$ data. Using an SED radiative transfer model of starbursts covering the wavelength range UV–submm, we derived photometric redshifts from the optical-MIR SEDs of 18$\mu $m-selected galaxies. From the best-fit SED models, we showed that the IRC all-band photometry is capable of tracing a steep rise in the flux at the blue side of the polycyclic aromatic hydrocarbon (PAH) 6.2$\mu $m emission feature. This indicates that the IRC all-band photometry is useful to constrain the redshift of infrared galaxies, specifically for dusty galaxies with a less prominent 4000Å break. Also, we found that the flux dip between the PAH 7.7 and 11.2$\mu $m emission feature is recognizable in the observed SEDs of galaxies at $z \sim 1$. This pilot study suggests the possibility of detecting many interesting galaxy properties in the NEP-Deep and Wide surveys, such as a systematic difference in SEDs between high–and low-$z$ Ultra-Luminous InfraRed Galaxies, and a large variation of the PAH inter-band strength ratio in galaxies at high redshifts.
Hinode SP Vector Magnetogram of AR10930 and Its Cross-Comparison with MDI
Authors: Moon Yong-Jae , Kim Yeon-Han , Park Young-Deuk , Ichimoto Kiyoshi , Sakurai Takashi , Chae Jongchul , Cho Kyung Suk , Bong Suchan , Suematsu Yoshinori , Tsuneta Saku , Katsukawa Yukio , Shimojo Masumi , Shimizu Toshifumi , Shine Richard A. , Tarbell Theodore D. , Title Alan M. , Lites Bruce , Kubo Masahito , Nagata Shin’ichi , Yokoyama Takaaki
Published: March 2014

We present one Hinode Spectropolarimeter (SP) magnetogram of AR 10930 that produced several major flares. The inversion from Stokes profiles to magnetic field vectors was made using the standard Milne-Eddington code. We successfully applied the Uniform Shear Method for resolving the 180$^{\circ}$ ambiguity to the magnetogram. The inversion gave very strong magnetic field strengths (near 4500 gauss) for a small portion of area in the umbra. Considering that the observed V-profile of 6301.5 Å was well-fitted as well as a direct estimation of the Zeeman splitting results in 4300–4600 gauss, we think that the field strengths should not be far from the actual value. A cross-comparison of the Hinode SP and SOHO MDI high resolution flux densities shows that the MDI flux density could be significantly underestimated by about a factor of two. In addition, it has a serious negative correlation (the so-called Zeeman saturation effect) with the Hinode SP flux density for umbral regions. Finally, we could successfully obtain a recalibrated MDI magnetogram that has been corrected for the Zeeman saturation effect using not only a pair of MDI intensity and magnetogram data simultaneously observed, but also the relationship from the cross-comparison between the Hinode SP and MDI flux densities.
Initial Helioseismic Observations by Hinode/SOT
Authors: Sekii Takashi , Kosovichev Alexander G. , Zhao Junwei , Tsuneta Saku , Shibahashi Hiromoto , Berger Thomas E. , Ichimoto Kiyoshi , Katsukawa Yukio , Lites Bruce , Nagata Shin’ichi , Shimizu Toshifumi , Shine Richard A. , Suematsu Yoshinori , Tarbell Theodore D. , Title Alan M.
Published: March 2014

Results from initial helioseismic observations by the Solar Optical Telescope on-board Hinode are reported. It has been demonstrated that intensity oscillation data from the Broadband Filter Imager can be used for various helioseismic analyses. The $k$–$\omega$ power spectra, as well as the corresponding time–distance cross-correlation function, which promise high-resolution time–distance analysis below the 6-Mm travelling distance, were obtained for G-band and Ca II-H data. Subsurface supergranular patterns were observed from our first time–distance analysis. The results show that the solar oscillation spectrum is extended to much higher frequencies and wavenumbers, and the time–distance diagram is extended to much shorter travel distances and times than were observed before, thus revealing great potential for high-resolution helioseismic observations from Hinode.
Temperature and Density Structures of Solar Corona—A Test of Iron Line Diagnostic Capability of EIS Instrument on Board Hinode
Authors: Watanabe Tetsuya , Hara Hirohisa , Culhane Len , Harra Louise K. , Doschek George A. , Mariska John T. , Young Peter R.
Published: March 2014

Increased diagnostic capability of the EUV Imaging Spectrometer (EIS) aboard Hinode (former Solar-B) has been demonstrated with a set of iron emission lines emerging in the two EIS observing wavelength bands (170–210 Å and 250–290 Å) and their line-intensity ratios. “Abundance-uncertainty” free relative emission measure distributions as a function of temperature were deduced using only iron emission lines of various ionization stages. First-light spectra of a small active region show iron lines ranging from Fe VIII (185.2 Å and 186.6 Å) through Fe XVII (204.7 Å, 254.9 Å, and 269.4 Å). Spectra of a C-class flare confirms the presence of one of these higher temperature lines (Fe XVII at 254.9 Å) more clearly, as well showing Fe XXIV (192.0 Å and 255.1 Å) and Fe XXIII (263.8 Å), which are normally only seen at flare temperatures.
Hinode EUV Imaging Spectrometer Observations of Active Region Loop Morphology: Implications for Static Heating Models of Coronal Emission
Authors: Brooks David H. , Warren Harry P. , Ugarte-Urra Ignacio , Matsuzaki Keiichi , Williams David R.
Published: March 2014

Theoretically, magnetic fields are expected to expand as they rise above the photosphere and into the corona, so the apparent uniform cross-sections of active region loops are difficult to understand. There has been some debate as to whether coronal loops really have constant cross-sections, or are actually unresolved and composed of expanding threads within the constant cross-section envelopes. Furthermore, loop expansion is critical to the success or failure of hydrostatic models in reproducing the intensities and morphology of observed emission. We analyze Hinode EIS (EUV Imaging Spectrometer) observations of loops in active region 10953 and detect only moderate apex width expansion over a broad range of temperatures from $\log T_{\rm e}/$ K $=$ 5.6 to 6.25. The expansion is less than required by steady-state heating models of coronal emission suggesting that such models will have difficulty reproducing both low and high temperature loop emission simultaneously. At higher temperatures ($\gt \log T_{\rm e}/\gt \log T_{\rm e}/$ K $=$ 6.3) the apex widths increase substantially, but the emission at these temperatures likely comes from a combination of multiple loops. These observations demonstrate the advantage of EIS over previous instruments. For the first time, active region loops can be examined over a broad temperature range with high temperature fidelity and the same spatial resolution. The results therefore provide further clues to the coronal heating timescale and thus have implications for the direction of future modeling efforts.
On Connecting the Dynamics of the Chromosphere and Transition Region with Hinode SOT and EIS
Authors: Hansteen Viggo H. , De Pontieu Bart , Carlsson Mats , McIntosh Scott , Watanabe Tetsuya , Warren Harry P. , Harra Louise K. , Hara Hirohisa , Tarbell Theodore D. , Shine Dick , Title Alan M. , Schrijver Carolus J. , Tsuneta Saku , Katsukawa Yukio , Ichimoto Kiyoshi , Suematsu Yoshinori , Shimizu Toshifumi
Published: March 2014

We use coordinated Hinode SOT/EIS observations that include high-resolution magnetograms, chromospheric, and transition region (TR) imaging, and TR/coronal spectra in a first test to study how the dynamics of the TR are driven by the highly dynamic photospheric magnetic fields and the ubiquitous chromospheric waves. Initial analysis shows that these connections are quite subtle and require a combination of techniques including magnetic field extrapolations, frequency-filtered time-series, and comparisons with synthetic chromospheric and TR images from advanced 3D numerical simulations. As a first result, we find signatures of magnetic flux emergence as well as 3 and 5 mHz wave power above regions of enhanced photospheric magnetic field in both chromospheric, transition region, and coronal emission.
Solar Transition Region Features Observed with Hinode/EIS
Authors: Young Peter R. , Zanna Del Giulio , Mason Helen E. , Doschek George A. , Culhane Len , Hara Hirohisa
Published: March 2014

Two types of solar active region feature prominent at transition region temperatures are identified in Hinode/EIS data of AR 10938 taken on 2007 January 20. The footpoints of 1 MK TRACE loops are shown to emit strongly in emission lines formed at $\log~T=$ 5.4–5.8, allowing the temperature increase along the footpoints to be clearly seen. A density diagnostic of Mg VII yields the density in the footpoints, with one loop showing a decrease from $3\times 10^9$ cm$^{-3}$ at the base to 1.5$\times$10$^9$ cm$^{-3}$ at a projected height of 20 Mm. The second feature is a compact active region transition region brightening which is particularly intense in O V emission ($\log~T=$ 5.4) but also has a signature at temperatures up to $\log~T=$ 6.3. The Mg VII diagnostic gives a density of $4\times 10^{10}$ cm$^{-3}$, and emission lines of Mg VI and Mg VII show line profiles broadened by 50 km s$^{-1}$ and wings extending beyond $\pm$200 km s$^{-1}$. Continuum emission in the short wavelength band is also found to be enhanced, and is suggested to be free-bound emission from recombination onto He$^+$.
Magnetic Feature and Morphological Study of X-Ray Bright Points with Hinode
Authors: Kotoku Jun’ichi , Kano Ryouhei , Tsuneta Saku , Katsukawa Yukio , Shimizu Toshifumi , Sakao Taro , Shibasaki Kiyoto , DeLuca Edward E. , Korreck Kelly E. , Golub Leon , Bobra Monica
Published: March 2014

We observed X-ray bright points (XBPs) in a quiet region of the Sun with the X-Ray Telescope (XRT) aboard the Hinode satellite on 2006 December 19. XRT’s high-resolution X-ray images revealed many XBPs with complicated structure and evolving dramatically with time. Almost all of the dynamic eruptions in the quiet region were composed of XBPs, and they had either loop or multiloop shapes, as is observed in larger flares. Brightening XBPs had strong magnetic fields with opposite polarities near their footpoints. While we have found a possible example of associated magnetic cancellation, other XBPs brighten and fade without any associated movement of the photospheric magnetic field.
Small-Scale X-Ray/EUV Jets Seen in Hinode XRT and TRACE
Authors: Kim Yeon-Han , Moon Young-Jae , Park Young-Deuk , Sakurai Takashi , Chae Jongchul , Cho Kyung Suk , Bong Su-Chan
Published: March 2014

We present the morphological and kinematic characteristics of three small-scale X-ray/EUV jets simultaneously observed by the Hinode XRT and the TRACE. For this, we examined all XRT movies with a thin Al/Poly filter from 2006 October 20 to 2007 April 8, and then found 34 small-scale eruptions. We next took a look at the corresponding TRACE 171/195 Å images associated with the eruptions. As a result, we found three simultaneous X-ray and EUV jets. For two different bands, they have similar characteristics in terms of the projected speed (90–310 km s$^{-1}$), lifetime (100–2000 s), and size (1.1–5$\times$10$^5$km). These characteristics are similar to the previous results by the Yohkoh SXT, but are quite different from EUV jets associated with H$\alpha$ surges. From the EUV Imaging Spectrometer, four spectral lines for the last event, we found blueshift (up to $-$64 km s$^{-1}$) and redshift (up to 20 km s$^{-1}$) motions as well as nonthermal velocities ranging from 57 to 106 km s$^{-1}$ at the jet footpoint. We note a tendency: the hotter the maximum ionization temperature is, the smaller the area of blueshift region is. These characteristics are consistent with a typical jet model that includes the magnetic reconnection between open coronal fields and emerging magnetic fields.
Hinode Observations of a Vector Magnetic Field Change Associated with a Flare on 2006 December 13
Authors: Kubo Masahito , Yokoyama Takaaki , Katsukawa Yukio , Lites Bruce , Tsuneta Saku , Suematsu Yoshinori , Ichimoto Kiyoshi , Shimizu Toshifumi , Nagata Shin’ichi , Tarbell Theodore D. , Shine Richard A. , Title Alan M. , Elmore David
Published: March 2014

Continuous observations of the flare productive active region 10930 were successfully carried out with the Solar Optical Telescope aboard the Hinode spacecraft during 2006 December 6 to 19. We focused on the evolution of photospheric magnetic fields in this active region, and the magnetic field properties at the site of the X3.4 class flare, using a time series of vector field maps with high spatial resolution. The X3.4 class flare occurred on 2006 December 13 at the apparent collision site between the large, opposite polarity umbrae. Elongated magnetic structures with alternatingly positive and negative polarities resulting from flux emergence appeared one day before the flare in the collision site penumbra. Subsequently, the polarity inversion line at the collision site became very complicated. The number of bright loops in Ca II H increased during the formation of these elongated magnetic structures. Flare ribbons and bright loops evolved along the polarity inversion line and one footpoint of the bright loop was located in a region having a large departure of the field azimuth angle with respect to its surroundings. SOT observations with high spatial resolution and high polarization precision revealed temporal change in the fine structure of magnetic fields at the flare site: some parts of the complicated polarity inversion line then disappeared, and in those regions the azimuth angle of the photospheric magnetic field changed by about 90°, becoming more spatially uniform within the collision site.
Evolution of the Sheared Magnetic Fields of Two X-Class Flares Observed by Hinode/XRT
Authors: Su Yingna , Golub Leon , Van Ballegooijen Adriaan , DeLuca Edward E. , Reeves Kathy K. , Sakao Taro , Kano Ryouhei , Narukage Noriyuki , Shibasaki Kiyoto
Published: March 2014

We present multi-wavelength observations of the evolution of the sheared magnetic fields in NOAA Active Region 10930, where two X-class flares occurred on 2006 December 13 and December 14, respectively. Observations made with the X-ray Telescope (XRT) and the Solar Optical Telescope (SOT) aboard Hinode suggest that the gradual formation of the sheared magnetic fields in this active region is caused by the rotation and west-to-east motion of an emerging sunspot. In the pre-flare phase of the two flares, XRT shows several highly sheared X-ray loops in the core field region, corresponding to a filament seen in the TRACE EUV observations. XRT observations also show that part of the sheared core field erupted, and another part of the sheared core field stayed behind during the flares, which may explain why a large part of the filament is still seen by TRACE after the flare. About 2–3 hours after the peak of each flare, the core field becomes visible in XRT again, and shows a highly sheared inner and less-sheared outer structure. We also find that the post-flare core field is clearly less sheared than the pre-flare core field, which is consistent with the idea that the energy released during the flares is stored in the highly sheared fields prior to the flare.
Discovery of a Temperature-Dependent Upflow in the Plage Region during a Gradual Phase of the X-Class Flare
Authors: Imada Shinsuke , Hara Hirohisa , Watanabe Tetsuya , Kamio Suguru , Asai Ayumi , Matsuzaki Keiichi , Harra Louise K. , Mariska John T.
Published: March 2014

We present Hinode/EIS raster scan observations of the plage region taken during the gradual phase of the GOES X3.2 flare that occurred on 2006 December 13. The plage region is located 200${}^{\prime\prime}$ east of the flare arcade. The plage region has a small transient coronal hole. The transient coronal hole is strongly affected by an X-class flare, and upflows are observed at its boundary. Multi-wavelength spectral observations allow us to determine velocities from the Doppler shifts at different temperatures. Strong upflows along with stationary plasma have been observed in the Fe XV line 284.2 Å (log$T/$ K $=6.3$) in the plage region. The strong upflows reach almost 150 km s$^{-1}$, which was estimated by a two-component Gaussian fitting. On the other hand, at a lower corona/transition region temperature (He II, 256.3 Å, log$T/$ K $=$ 4.9), very weak upflows, almost stationary, have been observed. We find that these upflow velocities clearly depend on the temperature with the hottest line, Fe XV, showing the fastest upflow velocity and the second-highest line, Fe XIV, showing the second-highest upflow velocity (130 km s$^{-1}$). All velocities are below the sound speed. The trend of the upflow dependence on temperature dramatically changes at 1 MK. These results suggest that heating may have an important role for strong upflow.
Hinode Calibration for Precise Image Co-Alignment between SOT and XRT (2006 November–2007 April)
Authors: Shimizu Toshifumi , Katsukawa Yukio , Matsuzaki Keiichi , Ichimoto Kiyoshi , Kano Ryohei , DeLuca Edward E. , Lundquist Loraine L. , Weber Mark , Tarbell Theodore D. , Shine Richard A. , Sôma Mitsuru , Tsuneta Saku , Sakao Taro , Minesugi Kenji
Published: March 2014

To understand the physical mechanisms for activity and heating in the solar atmosphere, the magnetic coupling from the photosphere to the corona is an important piece of information from the Hinode observations, and therefore precise positional alignment is required among the data acquired by different telescopes. The Hinode spacecraft and its onboard telescopes were developed to allow us to investigate magnetic coupling with co-alignment accuracy better than 1$^{\prime\prime}$. Using the Mercury transit observed on 2006 November 8 and co-alignment measurements regularly performed on a weekly basis, we have determined the information necessary for precise image co-alignment, and have confirmed that co-alignment better than 1$^{\prime\prime}$ can be realized between Solar Optical Telescope (SOT) and X-Ray Telescope (XRT) with our baseline co-alignment method. This paper presents results from the calibration for precise co-alignment of CCD images from SOT and XRT.
Wavelength Determination for Solar Features Observed by the EUV Imaging Spectrometer on Hinode
Authors: Brown Charles M. , Hara Hirohisa , Kamio Suguru , Feldman Uri , Seely John F. , Doschek George A. , Mariska John T. , Korendyke Clarence M. , Lang James , Dere Kenneth P. , Culhane Len , Thomas Roger J. , Davila Joseph M.
Published: March 2014

A wavelength calibration of solar lines observed by the high resolution EUV Imaging Spectrometer (EIS) on the Hinode satellite is reported. Spectral features of the quiet sun and of two mildly active areas were measured and calibrated. A listing of the stronger observed lines with identification of the leading contributor ions is presented. 41 lines are reported, with 90% identified. Wavelength precisions (2$\sigma$) of $\pm$0.0031 Å for the EIS short band and $\pm$0.0029 Å for the EIS long band are obtained. These lines, typical of 1–$2\times 10^{6}$ K plasmas, are recommended as standards for the establishment of EIS wavelength scales. The temperature of EIS varies by about $1\rlap{.}^{\circ}5$ C around the orbit and also with spacecraft pointing. The correlation of these temperature changes with wavelength versus pixel number scale changes is reported.