1.3 mm wavelength VLBI of sagittarius A*: Detection of time-variable emission on event horizon scales

Vincent L. Fish, Sheperd S. Doeleman, Christopher Beaudoin, Ray Blundell, David E. Bolin, Geoffrey C. Bower, Richard Chamberlin, Robert Freund, Per Friberg, Mark A. Gurwell, Mareki Honma, Makoto Inoue, Thomas P. Krichbaum, James Lamb, Daniel P Marrone, James M. Moran, Tomoaki Oyama, Richard Plambeck, Rurik Primiani, Alan E E RogersDaniel L. Smythe, Jason Soohoo, Peter A Strittmatter, Remo P J Tilanus, Michael Titus, Jonathan Weintroub, Melvyn Wright, David Woody, Ken H. Young, Lucy M Ziurys

Research output: Contribution to journalArticle

132 Citations (Scopus)

Abstract

Sagittarius A*, the ∼4 × 106 M 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*.

Original languageEnglish (US)
JournalAstrophysical Journal Letters
Volume727
Issue number2 PART II
DOIs
StatePublished - Feb 1 2011

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event horizon
very long baseline interferometry
interferometry
wavelength
night
wavelengths
telescopes
radii
interferometer
triangles
quasars
closures
observatories
interferometers
flux density
observatory
detection
radio
sensitivity

Keywords

  • Galaxy: center
  • Submillimeter: general
  • Techniques: high angular resolution
  • Techniques: interferometric

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

1.3 mm wavelength VLBI of sagittarius A* : Detection of time-variable emission on event horizon scales. / Fish, Vincent L.; Doeleman, Sheperd S.; Beaudoin, Christopher; Blundell, Ray; Bolin, David E.; Bower, Geoffrey C.; Chamberlin, Richard; Freund, Robert; Friberg, Per; Gurwell, Mark A.; Honma, Mareki; Inoue, Makoto; Krichbaum, Thomas P.; Lamb, James; Marrone, Daniel P; Moran, James M.; Oyama, Tomoaki; Plambeck, Richard; Primiani, Rurik; Rogers, Alan E E; Smythe, Daniel L.; Soohoo, Jason; Strittmatter, Peter A; Tilanus, Remo P J; Titus, Michael; Weintroub, Jonathan; Wright, Melvyn; Woody, David; Young, Ken H.; Ziurys, Lucy M.

In: Astrophysical Journal Letters, Vol. 727, No. 2 PART II, 01.02.2011.

Research output: Contribution to journalArticle

Fish, VL, Doeleman, SS, Beaudoin, C, Blundell, R, Bolin, DE, Bower, GC, Chamberlin, R, Freund, R, Friberg, P, Gurwell, MA, Honma, M, Inoue, M, Krichbaum, TP, Lamb, J, Marrone, DP, Moran, JM, Oyama, T, Plambeck, R, Primiani, R, Rogers, AEE, Smythe, DL, Soohoo, J, Strittmatter, PA, Tilanus, RPJ, Titus, M, Weintroub, J, Wright, M, Woody, D, Young, KH & Ziurys, LM 2011, '1.3 mm wavelength VLBI of sagittarius A*: Detection of time-variable emission on event horizon scales', Astrophysical Journal Letters, vol. 727, no. 2 PART II. https://doi.org/10.1088/2041-8205/727/2/L36
Fish, Vincent L. ; Doeleman, Sheperd S. ; Beaudoin, Christopher ; Blundell, Ray ; Bolin, David E. ; Bower, Geoffrey C. ; Chamberlin, Richard ; Freund, Robert ; Friberg, Per ; Gurwell, Mark A. ; Honma, Mareki ; Inoue, Makoto ; Krichbaum, Thomas P. ; Lamb, James ; Marrone, Daniel P ; Moran, James M. ; Oyama, Tomoaki ; Plambeck, Richard ; Primiani, Rurik ; Rogers, Alan E E ; Smythe, Daniel L. ; Soohoo, Jason ; Strittmatter, Peter A ; Tilanus, Remo P J ; Titus, Michael ; Weintroub, Jonathan ; Wright, Melvyn ; Woody, David ; Young, Ken H. ; Ziurys, Lucy M. / 1.3 mm wavelength VLBI of sagittarius A* : Detection of time-variable emission on event horizon scales. In: Astrophysical Journal Letters. 2011 ; Vol. 727, No. 2 PART II.
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abstract = "Sagittarius A*, the ∼4 × 106 M ⊙ 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*.",
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AU - Blundell, Ray

AU - Bolin, David E.

AU - Bower, Geoffrey C.

AU - Chamberlin, Richard

AU - Freund, Robert

AU - Friberg, Per

AU - Gurwell, Mark A.

AU - Honma, Mareki

AU - Inoue, Makoto

AU - Krichbaum, Thomas P.

AU - Lamb, James

AU - Marrone, Daniel P

AU - Moran, James M.

AU - Oyama, Tomoaki

AU - Plambeck, Richard

AU - Primiani, Rurik

AU - Rogers, Alan E E

AU - Smythe, Daniel L.

AU - Soohoo, Jason

AU - Strittmatter, Peter A

AU - Tilanus, Remo P J

AU - Titus, Michael

AU - Weintroub, Jonathan

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AU - Young, Ken H.

AU - Ziurys, Lucy M

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KW - Submillimeter: general

KW - Techniques: high angular resolution

KW - Techniques: interferometric

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