51 citations · 238 across the 19 of their papers we have counts for
15 papers · 1 filter
Circum-nuclear eccentric gas flow in the Galactic Center revealed by ALMA CMZ Exploration Survey (ACES)
Yoshiaki Sofue, Tomoharu Oka, Steven N. Longmore +41
We analyze the CS (J=2-1) line cube from the internal data release obtained by the large-scale program "ALMA CMZ Exploration Survey (ACES)" to investigate the kinematic structure o…
Parabolic-like Trend in SiO Ratios throughout the Central Molecular Zone: Possible Signature of a Past Nuclear Activity in the Galactic Center
Shunya Takekawa, Tomoharu Oka, Shiho Tsujimoto +5
We report the discovery of a characteristic trend in the intensity ratios of SiO emissions across the Central Molecular Zone (CMZ) of our Galaxy. Using the Nobeyama Radio Observato…
ALMA View of the High-velocity-dispersion Compact Cloud CO 0.02-0.02 at the Galactic Center
Yuhei Iwata, Tomoharu Oka, Shunya Takekawa +2
We report the results of observations toward the center of the molecular cloud CO 0.02-0.02 made using the Atacama Large Millimeter/Submillimeter Array. The successfully obtained 1…
Discovery of the Tadpole Molecular Cloud near the Galactic Nucleus
Miyuki Kaneko, Tomoharu Oka, Hiroki Yokozuka +4
In this paper, we report the discovery of an isolated, peculiar compact cloud with a steep velocity gradient at $2\farcm 6$ northwest of Sgr A*. This ``Tadpole'' molecular cloud is…
Catalog of High Velocity Dispersion Compact Clouds in the Central Molecular Zone of Our Galaxy
Tomoharu Oka, Asaka Uruno, Rei Enokiya +5
This study developed an automated identification procedure for compact clouds with broad velocity widths in the spectral line data cubes of highly crowded regions. The procedure wa…
Broad-velocity-width Molecular Features in the Galactic Plane
Hiroki Yokozuka, Tomoharu Oka, Shunya Takekawa +2
We performed a systematic search for broad-velocity-width molecular features (BVFs) in the disk part of our Galaxy by using the CO J = 1-0 survey data obtained with the Nobeyama Ra…
New Look at the Molecular Superbubble Candidate in the Galactic Center
Shiho Tsujimoto, Tomoharu Oka, Shunya Takekawa +10
The region in the Galactic center is characterized by multiple shell-like structures and their extremely broad velocity widths. We revisit the molecular supe…
The Fifth Candidate for an Intermediate-mass Black Hole in the Galactic Center
Shunya Takekawa, Tomoharu Oka, Yuhei Iwata +2
We report the results of high-resolution molecular line observations of the high-velocity compact cloud HCN-0.085-0.094 with the Atacama Large Millimeter/submillimeter Array. The H…
An energetic high-velocity compact cloud: CO0.31+0.11
Shunya Takekawa, Tomoharu Oka, Sekito Tokuyama +5
We have discovered an energetic high-velocity compact cloud CO0.31+0.11 in the central molecular zone of our Galaxy. CO0.31+0.11 is located at a projected distance of $\sim 4…
Indication of Another Intermediate-mass Black Hole in the Galactic Center
Shunya Takekawa, Tomoharu Oka, Yuhei Iwata +2
We report the discovery of molecular gas streams orbiting around an invisible massive object in the central region of our Galaxy, based on the high-resolution molecular line observ…
Detection of Another Molecular Bubble in the Galactic Center
Shiho Tsujimoto, Tomoharu Oka, Shunya Takekawa +4
The region in the Galactic center has a high CO =3-2/=1-0 intensity ratio and extremely broad velocity width. This paper reports the detection of five expand…
Millimetre-wave Emission from an Intermediate-Mass Black Hole Candidate in the Milky Way
Tomoharu Oka, Shiho Tsujimoto, Yuhei Iwata +2
It is widely accepted that black holes (BHs) with masses greater than a million solar masses (Msun) lurk at the centres of massive galaxies. The origins of such `supermassive' blac…
Discovery of Two Small High-Velocity Compact Clouds in the Central 10 Parsecs of Our Galaxy
Shunya Takekawa, Tomoharu Oka, Yuhei Iwata +2
We discovered two small high-velocity compact clouds (HVCCs) in HCN and maps of the central 20 pc of our Galaxy. Both HVCCs have broad velocity widths ($ΔV \gtrsim…
Distance to the Low-velocity Cloud in the Direction of the High-velocity Compact Cloud CO--0.40--0.22
Yuhei Iwata, Haruka Kato, Daisuke Sakai +1
CO--0.40--0.22 is a peculiar molecular cloud that is compact and has an extraordinary broad velocity width. It is found in the central molecular zone of our Galaxy. In this directi…
Kinematics of Ultra-High-Velocity Gas in the Expanding Molecular Shell adjacent to the W44 Supernova Remnant
Masaya Yamada, Tomoharu Oka, Shunya Takekawa +6
We mapped the ultra-high-velocity feature (the "Bullet") detected in the expanding molecular shell associated with the W44 supernova remnant using the Nobeyama Radio Observatory 45…