230 GHz VLBI OBSERVATIONS OF M87: EVENT‐HORIZON‐SCALE STRUCTURE DURING AN ENHANCED VERY‐HIGH‐ENERGY γ‐RAY STATE IN 2012

We report on 230 GHz (1.3 mm) very long baseline interferometry (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 GHz VLBI interferometric phase information...

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Bibliographic Details
Main Authors: Lu, Rusen (Contributor), Fish, Vincent L. (Contributor), Doeleman, Sheperd Samuel (Contributor), Cappallo, Roger J. (Contributor), Crew, Geoffrey B. (Contributor), Rogers, Alan E. E. (Contributor), SooHoo, Jason G. (Contributor), Titus, Michael A. (Contributor)
Other Authors: Haystack Observatory (Contributor)
Format: Article
Language:English
Published: IOP Publishing, 2015-09-01T19:40:35Z.
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Online Access:Get fulltext
LEADER 02403 am a22003373u 4500
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042 |a dc 
100 1 0 |a Lu, Rusen  |e author 
100 1 0 |a Haystack Observatory  |e contributor 
100 1 0 |a Lu, Rusen  |e contributor 
100 1 0 |a Fish, Vincent L.  |e contributor 
100 1 0 |a Doeleman, Sheperd Samuel  |e contributor 
100 1 0 |a Cappallo, Roger J.  |e contributor 
100 1 0 |a Crew, Geoffrey B.  |e contributor 
100 1 0 |a Rogers, Alan E. E.  |e contributor 
100 1 0 |a SooHoo, Jason G.  |e contributor 
100 1 0 |a Titus, Michael A.  |e contributor 
700 1 0 |a Fish, Vincent L.  |e author 
700 1 0 |a Doeleman, Sheperd Samuel  |e author 
700 1 0 |a Cappallo, Roger J.  |e author 
700 1 0 |a Crew, Geoffrey B.  |e author 
700 1 0 |a Rogers, Alan E. E.  |e author 
700 1 0 |a SooHoo, Jason G.  |e author 
700 1 0 |a Titus, Michael A.  |e author 
245 0 0 |a 230 GHz VLBI OBSERVATIONS OF M87: EVENT‐HORIZON‐SCALE STRUCTURE DURING AN ENHANCED VERY‐HIGH‐ENERGY γ‐RAY STATE IN 2012 
260 |b IOP Publishing,   |c 2015-09-01T19:40:35Z. 
856 |z Get fulltext  |u http://hdl.handle.net/1721.1/98305 
520 |a We report on 230 GHz (1.3 mm) very long baseline interferometry (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 GHz VLBI interferometric phase information on M87 through measurement of the closure phase on the triangle of long baselines. Most of the measured closure phases are consistent with 0° as expected by physically motivated models for 230 GHz structure such as jet models and accretion disk models. The brightness temperature of the event-horizon-scale structure is ~1 X 10[superscript 10] K derived from the compact flux density of ~1 Jy and the angular size of ~40 µas ~ 5.5 R[subscript s], which is broadly consistent with the peak brightness of the radio cores at 1-86 GHz located within ~10[superscript 2] R[subscript s]. Our observations occurred in the middle of an enhancement in very-high-energy (VHE) γ-ray flux, presumably originating in the vicinity of the central black hole. Our measurements, combined with results of multi-wavelength observations, favor a scenario in which the VHE region has an extended size of ~20-60 R[subscript s]. 
546 |a en_US 
655 7 |a Article 
773 |t The Astrophysical Journal