7,643 research outputs found

    Galaxy alignment on large and small scales

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    Galaxies are not randomly distributed across the universe but showing different kinds of alignment on different scales. On small scales satellite galaxies have a tendency to distribute along the major axis of the central galaxy, with dependence on galaxy properties that both red satellites and centrals have stronger alignment than their blue counterparts. On large scales, it is found that the major axes of Luminous Red Galaxies (LRGs) have correlation up to 30Mpc/h. Using hydro-dynamical simulation with star formation, we investigate the origin of galaxy alignment on different scales. It is found that most red satellite galaxies stay in the inner region of dark matter halo inside which the shape of central galaxy is well aligned with the dark matter distribution. Red centrals have stronger alignment than blue ones as they live in massive haloes and the central galaxy-halo alignment increases with halo mass. On large scales, the alignment of LRGs is also from the galaxy-halo shape correlation, but with some extent of mis-alignment. The massive haloes have stronger alignment than haloes in filament which connect massive haloes. This is contrary to the naive expectation that cosmic filament is the cause of halo alignment.Comment: 4 pages, 3 figures, To appear in the proceedings of the IAU Symposium 308 "The Zeldovich Universe: Genesis and Growth of the Cosmic Web

    Scouting, Signaling, and Gatekeeping: Chinese Naval Operations in Japanese Waters and the International Law Implications

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    In October 2008, a month after Prime Minister Shinzo Abe of Japan stepped down and the more hawkish Taro Aso took office, a Chinese flotilla of four People\u27s Liberation Army Navy (PLAN) ships transited from west to east through Japan\u27s narrow Tsugaru Strait en route to the Pacific Ocean. The vessels were observed together in the Sea of Japan, headed east toward the strait, by a Japan Maritime Self-Defense Force (JMSDF) P-3C patrol aircraft; they were about twenty-five nautical miles west-southwest of Tappizaki, the cape at the northern tip of the Tsugaru Peninsula, where the Sea of Japan enters the Tsugaru Strait between the islands of Honshu and Hokkaido. The flotilla consisted of a Sovremennyy-class missile destroyer-one of four China bought from Russia between 1996 and 2002 a supply ship, and two Jiangkai frigates, one of which was a newly commissioned Jiangkai II. Apparently the Sovremennyy and one of the frigates had recently paid a friendly visit to a naval base in the Russian Far East before joining the other two Chinese naval vessels in the Sea of Japan and proceeding on through the strait to the Pacific Ocean.https://digital-commons.usnwc.edu/cmsi-red-books/1001/thumbnail.jp

    Military Activities in the EEZ: A U.S.-China Dialogue on Security and International Law in the Maritime Commons

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    On the wall in the entranceway to the personal offices of the Commander, Pacific Fleet, there hangs prominently displayed a life-size portrait of Adm. Chester William Nimitz, the legendary architect of the American naval victory in the Pacific sixty-five years ago. The painting is specially lit, giving the admiral\u27s thoughtful gaze a lifelike glow as if he were present, judging the decisions and actions of his successors in command as these officers find means to preserve regional peace and guard American interests. In the painting\u27s background are the objects of naval war, standing as striking reminders of the heavy price in American blood and treasure paid for the nearly three generations since then during which the Pacific Ocean has been an American lake. It has been this freedom from serious threat that has provided room for American strategic and operational maneuver during the Korean conflict, the Vietnam War, and the Cold War, that has afforded an avenue for the movement of forces during conflicts in Iraq and Afghanistan, the capacity to deter conflict in East Asia, the access needed to assure the security of allies and partners, and the ability to provide support to populations devastated by disaster.https://digital-commons.usnwc.edu/cmsi-red-books/1006/thumbnail.jp
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