PoS(11th EVN Symposium)056 292, − http://pos.sissa.it/ creased baseline coverage will ually image the Schwarzschild servations have been successful the black hole in the center of M87, a, and California, with telescopes in otating in a prograde sense around a s in AGN sources such as 1924 oles using 1.3 mm VLBI. Observations essions as well. Sensitivity upgrades— ed; and the detection of cross-polarized on three recent results: the detection of ructure in at least one source. e Commons Attribution-NonCommercial-ShareAlike Licence. ∗ [email protected] fringes, which hints at complicated linear polarization st which allow their submilliarcsecond structure to be modell Speaker. Schwarzschild radius–structure in the 1.3 mm emissionwhich from strongly supports the existence ofrotating an black accretion hole; disk the r detection of nonzero closure phase The Event Horizon Telescope isradius–scale structure a around project nearby supermassive to black h observein and recent years event have made use ofChile telescopes and in Europe Hawaii, Arizon likely to participate inincluding future observing an s ongoing project to phase upsoon the make ALMA array—and imaging in a reality.in In producing the scientific meantime, results. non-imaging This ob contribution reports ∗ Copyright owned by the author(s) under the terms of the Creativ c 11th European VLBI Network Symposium &October Users 9-12, Meeting, 2012 Bordeaux, France

MIT Haystack Observatory, USA E-mail: Vincent Fish New results from the Event Horizon Telescope PoS(11th EVN Symposium)056 × 6 . 6 ) of the ∼ r resolu- lateau de requency Sch South Pole r Vincent Fish inclusion in s of ( rnia. Phased and 2012, with gittarius A*) and lemented. In the pe (SMT), and the of the EHT is well- tflow region, where Most importantly, a rge Millimeter Tele- arge Millimeter/sub- altech Submillimeter rces via non-imaging na Kea—the Submil- pposite direction very ve supermassive black ins to match ALMA’s s to improve the array the black hole with this ference proceedings [7]. tems are being developed cope to Summit Station in ns with the US telescopes s [8, 9]. s to the Atacama Pathfinder 2 coverage of the array (Fig. 1). Funding has been secured to equip the ) v , u ( [14]. A prominent jet is launched from this black hole, with a core shift with f ⊙ The Event Horizon Telescope (EHT) is a collaborative project to obser Science observations with the EHT have been taken in 2007, 2009, 2011, New telescopes will also come on line in the upcoming years, improving the angula Several upgrades to improve the sensitivity of the array are underway. The giant elliptical galaxy M87 is believed to host a central black hole with a mas M 9 New results from the Event Horizon Telescope 1. Introduction holes at a wavelength of 1.3matched mm to with the a angular global sizes VLBI ofM87. the array black The [1]. holes primary The in goal resolution the of center thegeneral of array the relativistic is Milky to effects Way (Sa image dominate, thesensitivity innermost around and accretion Sgr and resolution ou A* in andmeantime, order substantial M87. to scientific progress achieve is Upgrade this being mademethods goal on [2, these are 3, and 4, currently other 5]. sou being imp 2. Status of the EHT tion and several other test observations alongin the the way. array are Results reported fromlimeter here: Array observatio the (SMA), the three James submillimeter Clerk observatories MaxwellObservatory on Telescope (CSO)—, (JCMT), Mau and the the Arizona C RadioCombined Observatory Array Submillimeter for Telesco Researcharray in processors Millimeter-wave were Astronomy used (CARMA) atExperiment in the (APEX) SMA Califo telescope and in CARMA Chile are [6]. reportedThe First elsewhere Institut in fringe de these con Radioastronomie MillimétriqueBure telescopes—the Interferometer 30 in m France—have also in successfully Spain obtained and fringe the P multinational team is developing a phasedMillimeter array Array processor (ALMA) for the that AtacamaVLBI will L arrays turn it [10, into 11,bandwidth. an 12]. Next-generation extremely digital sensitive US backends aperture andto EHT for capture Mark sites and 6 record are recording these sys upgrading data. their signal cha 10 Telescope with VLBI receivers andscope instrumentation. in Mexico Construction continues. There of are theGreenland also [13]. La prospects of relocating a teles 3. M87 black hole [15]. The basenear of a the very black weak hole counterjet position atposition. [16], 7 mm providing is further seen evidence in associating the o that suggests that the 1.3 mm emission is located within a few Schwarzschild radii PoS(11th EVN Symposium)056 as µ lescopes Vincent Fish ollimated via ow. Particles are shown in red, JCMT- the emission, 40 lengths (circles [17]) and tion flow, known as the e shows the best-fit Gaussian with a . ). Red squares show telescopes that have Sch r jet-width profile at an apparent core dis- e). right ares show the locations of future telescopes. 3 / rger jet (black line [18]) and inner jet (magenta [19]) that produce a parabolic profile for the jet 2 range in cyan [4]) is significantly smaller than the r σ 3 ) and M87 ( left , or a deprojected distance of 2.5–4 Sch : The apparent jet size is consistent with data at longer wave r Right : EHT detections of M87 in 2009 [4]. SMT-CARMA detections are as. Left The EHT as viewed from Sgr A* ( µ ), is consistent with the expected size of an Sch r A plausible interpretation of these results is that the jet is being launched and c EHT observations of M87 at 1.3 mm using the JCMT, the SMT, and two CARMA te general relativistic magnetohydrodynamic models ofand the green la lines, labelled bywidth. inclination The to measured the 1.3 mm line size of (dark sight blue line with 3 (5.5 CARMA in cyan and magenta,size and of SMT-JCMT 40 in blue. The solid lin Figure 2: Figure 1: New results from the Event Horizon Telescope tance of about 1–2 successfully obtained fringes in the 1.3 mm band; yellow squ lensed size of the ISCO for a non-spinning black hole (red lin produced numerous detections on all baselines (Fig. 2) [4]. The size of the Blandford-Payne mechanism [20]most from efficiently a accelerated disk from wind the tied high-density to inner edge the of accretion the fl accre PoS(11th EVN Symposium)056 292, − losure 1 pc Vincent Fish closure phases cm−jet r a Schwarzschild ations in 2009 de- Mc2 cretion disk that is A* [3] and used to the next few years, of the components— cted on other sources, trongly correlated with nonzero r A* too. information is contained Mc1 function of the black hole at ers of asymmetric source l image of the 1.3 mm emis- : Model image of 1924 Mc0 Right nt models. rection of the larger-scale jet seen at centimeter 4 K in the downstream components—supports deceler- 5 . 10 292 are typically interspersed with the target source Sgr A* 292 measured with the EHT on the SMT-JCMT-CARMA triangle − − K in the core and 10 11 292 on all baselines at sufficiently high signal-to-noise ratio (S/N) to obtain c : Closure phases of 1924 − Left Although closure phase information has previously been reported on Sgr Observations of the quasar 1924 have been measured on a sourcein at the 1.3 mm. phases Most [26], ofstructure. and the source nonzero As structural closure the phases sensitivityhigh-S/N and are detection angular unambiguous of resolution nonzero mark of closure phases the should EHT become improve routine over in Sg constrain its structure [25], these observations represent the first time th ating or particle-cascade jet models [23]. Similar analyses are being condu including 3C 279 [24]. Figure 3: New results from the Event Horizon Telescope phase measurements [5]. These data have beension used to on construct a submilliarcsecond mode scales (Fig.approximately 3). 10 The low brightness temperatures in 2009 (green points) [5]. Colored lines show three differe to provide calibration information at the same elevation as Sgr A*. EHT observ tected 1924 innermost stable circular orbit (ISCO) [21]. The ISCO radius is a strong 4. Quasars showing three different components that curvewavelengths. toward the di spin. The measured size is significantlyblack smaller hole. than the Models lensed of ISCO the diameter inner fo the jet black of M87 hole find spin that the [22],likely apparent rotating consistent jet in size with a is prograde the s sense conclusion around that a high-spin M87 black hosts hole. an ac PoS(11th EVN Symposium)056 , , L17. , 323 Vincent Fish , in k Hole A&A , in proceedings Cross-polarized that the linearly , s in 2012, using ack Hole in M87 ow a and the CARMA ole candidate at the lts demonstrate that Variable Emission on Further analysis will . 11th European VLBI PoS(11th EVN array science , cross-polarized amplitude e similar to the total-intensity (2008) 012047. ristics are qualitatively different oss-polarized amplitude ratio on PoS(11th EVN 131 , (2009) 68 [arXiv:0906.3899]. 292 with the Event Horizon Telescope 11th European VLBI Network Symposium , in proceedings of 11th European VLBI Network Symposium & − . 11th European VLBI Network Symposium & . . 5 J. Phys. Conf. 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Anotherratios source on shows much interstate larger baselines thanpolarized on structure may the be intrasite quite CARMAbe different baseline, required from to suggesting the fully total-intensity interpret structure. the the era polarimetric of VLBI polarized data, 1.3 but mm these VLBI initial has begun. resu References New results from the Event Horizon Telescope 5. Polarization PoS(11th EVN Symposium)056 , e of 738 et ack holes Vincent Fish ApJ ASP Conf. , bservations , (1981) 529. 69 (1995) 11439. (2009) L126 92 An origin of the radio jet in , 394 Synthetic Synchrotron Maps IEEE Proc. , MNRAS , rferometry Closure Phases waguchi, N., ions Magnetically Driven Accretion in the Kerr (2011) 185. Constraining the Structure of Sagittarius , govalov, S.V., 477 e, S., Proc. Natl. Acad. Sci. , (2009) 503 [arXiv:0901.2634]. 6 Imaging a Jet Base—Prospects with M87 Nature , 695 (2009) 1164 [arXiv:0812.0366]. 878 [arXiv:astro-ph/0407092]. 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