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Molecular clouds in the NGC 6334 and NGC 6357 region: Evidence for a 100 pc-scale cloud-cloud collision triggering the Galactic mini-starbursts
Tachihara, Kengo; Fukui, Yasuo; Sano, Hidetoshi +7 more
We carried out new CO (J = 1-0, 2-1, and 3-2) observations with NANTEN2 and ASTE in the region of the twin Galactic mini-starbursts NGC 6334 and NGC 6357. We detected two velocity molecular components of 12 km s-1 velocity separation, which is continuous over 3° along the plane. In NGC 6334 the two components show similar two-peaked int…
Hitomi observation of radio galaxy NGC 1275: The first X-ray microcalorimeter spectroscopy of Fe-Kα line emission from an active galactic nucleus
Done, Chris; Safi-Harb, Samar; Hamaguchi, Kenji +191 more
The origin of the narrow Fe-Kα fluorescence line at 6.4 keV from active galactic nuclei has long been under debate; some of the possible sites are the outer accretion disk, the broad line region, a molecular torus, or interstellar/intracluster media. In 2016 February-March, we performed the first X-ray microcalorimeter spectroscopy with the Soft X…
Blue-wing enhancement of the chromospheric Mg II h and k lines in a solar flare
Heinzel, Petr; Shibata, Kazunari; Okamoto, Takenori J. +6 more
We performed coordinated observations of AR 12205, which showed a C-class flare on 2014 November 11, with the Interface Region Imaging Spectrograph (IRIS) and the Domeless Solar Telescope (DST) at Hida Observatory. Using spectral data in the Si IV 1403 Å, C II 1335 Å, and Mg II h and k lines from IRIS and the Ca II K, Ca II 8542 Å, and Hα lines fr…
Temperature structure in the Perseus cluster core observed with Hitomi
Done, Chris; Safi-Harb, Samar; Hamaguchi, Kenji +192 more
The present paper explains the temperature structure of X-ray emitting plasma in the core of the Perseus cluster based on 1.8-20.0 keV data obtained with the Soft X-ray Spectrometer (SXS) on board the Hitomi Observatory. A series of four observations was carried out, with a total effective exposure time of 338 ks that covered a central region of ∼…
ALMA 12CO (J = 1-0) imaging of the nearby galaxy M 83: Variations in the efficiency of star formation in giant molecular clouds
Nakanishi, Hiroyuki; Kuno, Nario; Kawabe, Ryohei +6 more
We present results of the 12CO (1-0) mosaic observations of the nearby barred-spiral galaxy M 83 obtained with the Atacama Large Millimeter/submillimeter Array (ALMA). The total flux is recovered by combining the ALMA data with single-dish data obtained using the Nobeyama 45 m telescope. The combined map covers a ∼13 kpc2 fie…
Formation of the young compact cluster GM 24 triggered by a cloud-cloud collision
Tachihara, Kengo; Fukui, Yasuo; Sano, Hidetoshi +7 more
High-mass star formation is an important step which controls galactic evolution. GM 24 is a heavily obscured star cluster including a single O9 star with more than ∼100 lower-mass stars within a 0.3 pc radius toward (l, b) ∼ (350.5°, 0.96°), close to the Galactic mini-starburst NGC 6334. We found two velocity components associated with the cluster…
The origin of recombining plasma and the detection of the Fe-K line in the supernova remnant W 28
Uchida, Hiroyuki; Tsuru, Takeshi Go; Tanaka, Takaaki +2 more
Overionized recombining plasmas (RPs) have been discovered from a dozen mixed-morphology (MM) supernova remnants (SNRs). However, their formation process is still under debate. As pointed out by many previous studies, spatial variations of plasma temperature and ionization state provide clues to understanding the physical origin of RPs. We report …
Molecular clouds toward three Spitzer bubbles S116, S117, and S118: Evidence for a cloud-cloud collision which formed the three H II regions and a 10 pc scale molecular cavity
Tachihara, Kengo; Fukui, Yasuo; Nishimura, Atsushi +6 more
We carried out a molecular-line study toward the three Spitzer bubbles S116, S117, and S118, which show active formation of high-mass stars. We found molecular gas consisting of two components with a velocity difference of ∼5 km s-1. One of them, the small cloud, has a typical velocity of -63 km s-1 and the other, the large c…
Detection of polarized gamma-ray emission from the Crab nebula with the Hitomi Soft Gamma-ray Detector
Done, Chris; Safi-Harb, Samar; Hamaguchi, Kenji +191 more
We present the results from the Hitomi Soft Gamma-ray Detector (SGD) observation of the Crab nebula. The main part of SGD is a Compton camera, which in addition to being a spectrometer, is capable of measuring polarization of gamma-ray photons. The Crab nebula is one of the brightest X-ray/gamma-ray sources on the sky, and the only source from whi…
Large-scale CO J = 1-0 observations of the giant molecular cloud associated with the infrared ring N35 with the Nobeyama 45 m telescope
Kuno, Nario; Tachihara, Kengo; Fukui, Yasuo +14 more
We report an observational study of the giant molecular cloud (GMC) associated with the Galactic infrared ring-like structure N35 and two nearby H II regions G024.392+00.072 (H II region A) and G024.510-00.060 (H II region B), using the new CO J = 1-0 data obtained as a part of the FOREST Unbiased Galactic Plane Imaging survey with the Nobeyama 45…