1.3 mm WAVELENGTH VLBI OF SAGITTARIUS A*: DETECTION OF TIME-VARIABLE EMISSION ON EVENT HORIZON SCALES

被引：151

作者：

Fish, Vincent L. ^{[1
]}

Doeleman, Sheperd S. ^{[1
]}

Beaudoin, Christopher ^{[1
]}

Blundell, Ray ^{[2
]}

Bolin, David E. ^{[1
]}

Bower, Geoffrey C. ^{[4
]}

Chamberlin, Richard ^{[5
]}

Freund, Robert ^{[3
]}

Friberg, Per ^{[6
]}

Gurwell, Mark A. ^{[2
]}

Honma, Mareki ^{[7
]}

Inoue, Makoto ^{[8
]}

Krichbaum, Thomas P. ^{[9
]}

Lamb, James ^{[10
]}

Marrone, Daniel P. ^{[11
]}

Moran, James M. ^{[2
]}

Oyama, Tomoaki ^{[7
]}

Plambeck, Richard ^{[4
]}

Primiani, Rurik ^{[2
]}

Rogers, Alan E. E. ^{[1
]}

Smythe, Daniel L. ^{[1
]}

SooHoo, Jason ^{[1
]}

Strittmatter, Peter ^{[3
]}

Tilanus, Remo P. J. ^{[6
,12
]}

Titus, Michael ^{[1
]}

Weintroub, Jonathan ^{[2
]}

Wright, Melvyn ^{[4
]}

Woody, David ^{[10
]}

Young, Ken H. ^{[2
]}

Ziurys, Lucy M. ^{[3
]}

机构：

[1] MIT, Haystack Observ, Westford, MA 01886 USA

[2] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA

[3] Univ Arizona, Steward Observ, Arizona Radio Observ, Tucson, AZ 85721 USA

[4] Univ Calif Berkeley, Radio Astron Lab, Dept Astron, Berkeley, CA 94720 USA

[5] Caltech Submillimeter Observ, Hilo, HI 96720 USA

[6] James Clerk Maxwell Telescope, Joint Astron Ctr, Hilo, HI 96720 USA

[7] Natl Inst Nat Sci, Natl Astron Observ Japan, Mitaka, Tokyo 1818588, Japan

[8] Acad Sinica, Inst Astron & Astrophys, Taipei 10617, Taiwan

[9] Max Planck Inst Radioastron, D-53121 Bonn, Germany

[10] CALTECH, OVRO, Big Pine, CA 93513 USA

[11] Univ Chicago, Kavli Inst Cosmol Phys, Chicago, IL 60637 USA

[12] Netherlands Org Sci Res, NL-2509 AC The Hague, Netherlands

来源：

ASTROPHYSICAL JOURNAL LETTERS | 2011年 / 727卷 / 02期

基金：

美国国家科学基金会;

关键词：

Galaxy: center; submillimeter: general; techniques: high angular resolution; techniques: interferometric; SUPERMASSIVE BLACK-HOLE; SGR-A; GALACTIC-CENTER; FLARE EMISSION; X-RAY; MILLIMETER VLBI; ACCRETION FLOW; STELLAR ORBITS; MILKY-WAY; SIMULATIONS;

D O I：

10.1088/2041-8205/727/2/L36

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Sagittarius A*, the similar to 4 x 10(6) M(circle dot) black hole candidate at the Galactic center, can be studied on Schwarzschild radius scales with (sub) millimeter wavelength very long baseline interferometry (VLBI). We report on 1.3 mm wavelength observations of Sgr A* using a VLBI array consisting of the JCMT on Mauna Kea, the Arizona Radio Observatory's Submillimeter Telescope on Mt. Graham in Arizona, and two telescopes of the CARMA array at Cedar Flat in California. Both Sgr A* and the quasar calibrator 1924-292 were observed over three consecutive nights, and both sources were clearly detected on all baselines. For the first time, we are able to extract 1.3 mm VLBI interferometer phase information on Sgr A* through measurement of closure phase on the triangle of baselines. On the third night of observing, the correlated flux density of Sgr A* on all VLBI baselines increased relative to the first two nights, providing strong evidence for time-variable change on scales of a few Schwarzschild radii. These results suggest that future VLBI observations with greater sensitivity and additional baselines will play a valuable role in determining the structure of emission near the event horizon of Sgr A*.

引用

页数：6