Browsing by Author "Gurwell, Mark"

Now showing items 1-8 of 8

    • 1.3 mm Wavelength VLBI of Sagittarius A*: Detection of Time-Variable Emission on Event Horizon Scales 

      Fish, Vincent L.; Doeleman, Sheperd Samuel; Beaudoin, Christopher; Blundell, Raymond; Bolin, David E.; Bower, Geoffrey C.; Chamberlin, Richard; Freund, Robert; Friberg, Per; Gurwell, Mark Andrew; Honma, Mareki; Inoue, Makoto; Krichbaum, Thomas P.; Lamb, James; Marrone, Daniel P.; Moran, James M.; Oyama, Tomoaki; Plambeck, Richard; Primiani, Rurik A.; Rogers, Alan E. E.; Smythe, Daniel L.; SooHoo, Jason; Strittmatter, Peter; Tilanus, Remo P. J.; Titus, Michael; Weintroub, Jonathan; Wright, Melvyn; Woody, David; Young, Ken Harbour; Ziurys, Lucy M. (IOP Publishing, 2011)
      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 ...

    • 230 GHz VLBI observations of M87: event-horizon-scale structure at the enhanced very-high-energy γ-ray state in 2012 

      Akiyama, Kazunori; Lu, Ru-Sen; Fish, Vincent; Doeleman, Sheperd S.; Broderick, Avery; Dexter, Jason; Hada, Kazuhiro; Kino, Motoki; Nagai, Hiroshi; Honma, Mareki; Johnson, Michael D.; Algaba, Juan; Asada, Keiichi; Brinkerink, Christiaan; Blundell, Raymond; Bower, Geoffrey; Cappallo, Roger; Crew, Geoffrey; Dexter, Matt; Dzib, Sergio; Freund, Robert; Friberg, Per; Gurwell, Mark Andrew; Ho, Paul; Inoue, Makoto; Krichbaum, Thomas; Loinard, Laurent; MacMahon, David; Marrone, Daniel; Moran, James M.; Nakamura, Masanori; Nagar, Neil; Ortiz-Leon, Gisela; Plambeck, Richard; Pradel, Nicolas; Primiani, Rurik A.; Rogers, Alan; Roy, Alan; SooHoo, Jason; Tavares, Jonathan-León; Tilanus, Remo; Titus, Michael; Wagner, Jan; Weintroub, Jonathan; Yamaguchi, Paul Isami; Young, Ken Harbour; Zensus, Anton; Ziurys, Lucy (IOP Publishing, 2015)
      We report on 230 GHz (1.3 mm) VLBI observations of M87 with the Event Horizon Telescope using antennas on Mauna Kea in Hawaii, Mt. Graham in Arizona and Cedar Flat in California. For the first time, we have acquired 230 ...

    • Fine-Scale Structure of the Quasar 3C 279 Measured with 1.3 mm Very Long Baseline Interferometry 

      Lu, Ru-Sen; Fish, Vincent L.; Akiyama, Kazunori; Doeleman, Sheperd S.; Algaba, Juan C.; Bower, Geoffrey C.; Brinkerink, Christiaan; Chamberlin, Richard; Crew, Geoffrey; Cappallo, Roger J.; Dexter, Matt; Freund, Robert; Friberg, Per; Gurwell, Mark Andrew; Ho, Paul T. P.; Honma, Mareki; Inoue, Makoto; Jorstad, Svetlana G.; Krichbaum, Thomas P.; Loinard, Laurent; MacMahon, David; Marrone, Daniel P.; Marscher, Alan P.; Moran, James M.; Plambeck, Richard; Pradel, Nicolas; Primiani, Rurik A.; Tilanus, Remo P. J.; Titus, Michael; Weintroub, Jonathan; Wright, Melvyn; Young, Ken Harbour; Ziurys, Lucy M. (American Astronomical Society, 2013)
      We report results from five day very long baseline interferometry observations of the well-known quasar 3C 279 at 1.3mm (230 GHz) in 2011. The measured nonzero closure phases on triangles including stations in Arizona, ...

    • First Detection of Millimeter/Submillimeter Extragalactic H2O Maser Emission 

      Humphreys, E. M. L.; Greenhill, L. J.; Reid, M. J.; Beuther, H.; Moran, James M.; Gurwell, Mark Andrew; Wilner, David J.; Kondratko, P. T. (IOP Publishing, 2005)
      We report the first detection of an extragalactic millimeter wavelength H2O maser at 183 GHz towards NGC 3079 using the Submillimeter Array (SMA), and a tentative submillimeter wave detection of the 439 GHz maser towards ...

    • Jet-Launching Structure Resolved Near the Supermassive Black Hole in M87 

      Doeleman, Sheperd Samuel; Fish, V. L.; Schenck, D. E.; Beaudoin, C.; Blundell, Raymond; Bower, G. C.; Broderick, Alithia Carol; Chamberlin, R.; Freund, R.; Friberg, P.; Gurwell, Mark Andrew; Ho, Po-Yi; Honma, M.; Inoue, M.; Krichbaum, T. P.; Lamb, J; Loeb, Abraham; Lonsdale, C.; Marrone, D. P.; Moran, James M.; Oyama, T.; Plambeck, R.; Primiani, Rurik A.; Rogers, A. E. E.; Smythe, D. L.; SooHoo, J.; Strittmatter, P.; Tilanus, R. P. J.; Titus, M.; Weintroub, Jonathan; Wright, Bennett Bennett; Young, K. H.; Ziurys, L. M. (American Association for the Advancement of Science (AAAS), 2012)
      Approximately 10% of active galactic nuclei exhibit relativistic jets, which are powered by accretion of matter onto super massive black holes. While the measured width profiles of such jets on large scales agree with ...

    • Persistent Asymmetric Structure of Sagittarius A* on Event Horizon Scales 

      Fish, Vincent; Johnson, Michael D.; Doeleman, Sheperd S.; Broderick, Avery; Psaltis, Dimitrios; Lu, Ru-Sen; Akiyama, Kazunori; Alef, Walter; Algaba, Juan; Asada, Keiichi; Beaudoin, Christopher; Bertarini, Alessandra; Blackburn, Lindy; Blundell, Raymond; Bower, Geoffrey; Brinkerink, Christiaan; Cappallo, Roger; Chael, Andrew Alan; Chamberlin, Richard; Chan, Chi-Kwan; Crew, Geoffrey; Dexter, Jason; Dexter, Matt; Dzib, Sergio; Falcke, Heino; Freund, Robert; Friberg, Per; Greer, Christopher; Gurwell, Mark Andrew; Ho, Paul; Honma, Mareki; Inoue, Makoto; Johannsen, Tim; Kim, Junhan; Krichbaum, Thomas; Lamb, James; León-Tavares, Jonathan; Loeb, Abraham; Loinard, Laurent; MacMahon, David; Marrone, Daniel; Moran, James M.; Mościbrodzka, Monika; Ortiz-León, Gisela; Oyama, Tomoaki; Özel, Feryal (American Astronomical Society, 2016)
      The Galactic Center black hole Sagittarius A* (Sgr A*) is a prime observing target for the Event Horizon Telescope (EHT), which can resolve the 1.3 mm emission from this source on angular scales comparable to that of the ...

    • Radio and Millimeter Monitoring of Sgr A*: Spectrum, Variability, and Constraints on the G2 Encounter 

      Bower, Geoffrey C.; Markoff, Sera; Dexter, Jason; Gurwell, Mark Andrew; Moran, James M.; Brunthaler, Andreas; Falcke, Heino; Fragile, P. Chris; Maitra, Dipankar; Marrone, Dan; Peck, Alison; Rushton, Anthony; Wright, Melvyn C. H. (IOP Publishing, 2015)
      We report new observations with the Very Large Array, Atacama Large Millimeter Array, and Submillimeter Array at frequencies from 1.0 to 355 GHz of the Galactic Center black hole, Sagittarius A*. These observations were ...

    • Submillimeter Array 440 μm/690 GHz Line and Continuum Observations of Orion KL 

      Beuther, H.; Zhang, Qizhou; Reid, Mark Jonathan; Hunter, T. R.; Gurwell, Mark Andrew; Wilner, David J.; Zhao, Jun-Hui; Shinnaga, H.; Keto, Eric R.; Ho, P. T. P.; Moran, James M.; Liu, S.‐Y. (IOP Publishing, 2006)
      Submillimeter Array observations of Orion-KL at ∼ 1′′ resolution in the 440 µm/690 GHz band reveal new insights about the continuum and line emission of the region. The 440 µm continuum flux density measurement from source ...