J/A+A/640/A69       3C 279 Event Horizon Telescope imaging          (Kim+, 2020)

Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution. Kim J.-Y., Krichbaum T.P., Broderick A.E., Wielgus M., Blackburn L., Gomez J.L., Johnson M.D., Bouman K.L., Chael A., Akiyama K., Jorstad S., Marscher A.P., Issaoun S., Janssen M., Chan C.-k., Savolainen T., Pesce D.W., Oezel F., Alberdi A., Alef W., Asada K., Azulay R., Baczko A.-K., Ball D., Balokovi'c M., Barrett J., Bintley D., Boland W., Bower G.C., Bremer M., Brinkerink C.D., Brissenden R., Britzen S., Broguiere D., Bronzwaer T., Byun D.-Y., Carlstrom J.E., Chatterjee S., Chatterjee K., Chen M.-T., Chen Y., Cho I., Christian P., Conway J.E., Cordes J.M., Crew G.B., Cui Y., Davelaar J., De Laurentis M., Deane R., Dempsey J., Desvignes G., Dexter J., Doeleman S.S., Eatough R.P., Falcke H., Fish V.L., Fomalont E., Fraga-Encinas R., Friberg P., Fromm C.M., Galison P., Gammie C.F., Garcia R., Gentaz O., Georgiev B., Goddi C., Gold R., Gu M., Gurwell M., Hada K., Hecht M.H., Hesper R., Ho L.C., Ho P., Honma M., Huang C.-W.L., Huang L., Hughes D.H., Ikeda S., Inoue M., James D.J., Jannuzi B.T., Jeter B., Jiang W., Jimenez-Rosales A., Jung T., Karami M., Karuppusamy R., Kawashima T., Keating G.K., Kettenis M., Kim J., Kim J., Kino M., Koay J.Y., Koch P.M., Koyama S., Kramer M., Kramer C., Kuo C.-Y., Lauer T.R., Lee S.-S., Li Y.-R., Li Z., Lindqvist M., Lico R., Liu K., Liuzzo E., Lo W.-P., Lobanov A.P., Loinard L., Lonsdale C., Lu R.-S., MacDonald N.R., Mao J., Marko S., Marrone D.P., Marti-Vidal I., Matsushita S., Matthews L.D., Medeiros L., Menten K.M., Mizuno Y., Mizuno I., Moran J.M., Moriyama K., Moscibrodzka M., Mueller C., Nagai H., Nagar N.M., Nakamura M., Narayan R., Narayanan G., Natarajan I., Neri R., Ni C., Noutsos A., Okino H., Olivares H., Ortiz-Leon G.N., Oyama T., Palumbo D.C.M., Park J., Patel N., Pen U.-L., Pietu V., Plambeck R., PopStefanija A., Porth O., Prather B., Preciado-Lopez J.A., Psaltis D., Pu H.-Y., Ramakrishnan V., Rao R., Rawlings M.G., Raymond A.W., Rezzolla L., Ripperda B., Roelofs F., Rogers A., Ros E., Rose M., Roshanineshat A., Rottmann H., Roy A.L., Ruszczyk C., Ryan B.R., Rygl K.L.J., Sanchez S., Sanchez-Arguelles D., Sasada M., Schloerb F.P., Schuster K.-F., Shao L., Shen Z., Small D., Sohn B.W., SooHoo J., Tazaki F., Tiede P., Tilanus R.P.J., Titus M., Toma K., Torne P., Trent T., Traianou E., Trippe S., Tsuda S., van Bemmel I., van Langevelde H.J., van Rossum D.R., Wagner J., Wardle J., Ward-Thompson D., Weintroub J., Wex N., Wharton R., Wong G.N., Wu Qi., Yoon D., Young A., Young K., Younsi Z., Yuan F., Yuan Y.-F., Zensus J.A., Zhao G., Zhao S.-S., Zhu Z., Algaba J.-C., Allardi A., Amestica R., Anczarski J., Bach U., Bagano F.K., Beaudoin C., Benson B.A., Berthold R., Blanchard J.M., Blundell R., Bustamente S., Cappallo R., Castillo-Dominguez E., Chang C.-C., Chang S.-H., Chang S.-C., Chen C.-C., Chilson R., Chuter T.C., Cordova Rosado R., Coulson I.M., Crowley J., Derome M., Dexter M., Dornbusch S., Dudevoir K.A., Dzib S.A., Eckart A., Eckert C., Erickson N.R., Everett W.B., Faber A., Farah J.R., Fath V., Folkers T.W., Forbes D.C., Freund R., Gomez-Ruiz A.I., Gale D.M., Gao F., Geertsema G., Graham D.A., Greer C.H., Grosslein R., Gueth F., Haggard D., Halverson N.W., Han C.-C., Han K.-C., Hao J., Hasegawa Y., Henning J.W., Hernandez-Gomez A., Herrero-Illana R., Heyminck S., Hirota A., Hoge J., Huang Y.-D., Impellizzeri C.M.V., Jiang H., John D., Kamble A., Keisler R., Kimura K., Kono Y., Kubo D., Kuroda J., Lacasse R., Laing R.A., Leitch E.M., Li C.-T., Lin L.C.-C., Liu C.-T., Liu K.-Y., Lu L.-M., Marson R.G., Martin-Cocher P.L., Massingill K.D., Matulonis C., McColl M.P., McWhirter S.R., Messias H., Meyer-Zhao Z., Michalik D., Montana A., Montgomerie W., Mora-Klein M., Muders D., Nadolski A., Navarro S., Neilsen J., Nguyen C.H., Nishioka H., Norton T., Nowak M.A., Nystrom G., Ogawa H., Oshiro P., Oyama T., Parsons H., Penalver J., Phillips N.M., Poirier M., Pradel N., Primiani R.A., Ran P.A., Rahlin A.S., Reiland G., Risacher C., Ruiz I., Saez-Madain A.F., Sassella R., Schellart P., Shaw P., Silva K.M., Shiokawa H., Smith D.R., Snow W., Souccar K., Sousa D., Sridharan T.K., Srinivasan R., Stahm W., Stark A.A., Story K., Timmer S.T., Vertatschitsch L., Walther C., Wei T.-S., Whitehorn N., Whitney A.R., Woody D.P., Wouterloot J.G.A., Wright M., Yamaguchi P., Yu C.-Y., Zeballos M., Zhang S., Ziurys L. (The Event Horizon Telescope Collaboration) <Astron. Astrophys. 640, A69 (2020)> =2020A&A...640A..69K (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, radio ; Interferometry Keywords: galaxies: active - galaxies: jets - galaxies: individual : 3C 279 - techniques : interferometric Abstract: 3C 279 is an archetypal blazar with a prominent radio jet that show broadband flux density variability across the entire electromagnetic spectrum. We use an ultra-high angular resolution technique - global Very Long Baseline Interferometry (VLBI) at 1.3mm (230GHz) - to resolve the innermost jet of 3C 279 in order to study its fine-scale morphology close to the jet base where highly variable gamma-ray emission is thought to originate, according to various models. The source was observed during four days in April 2017 with the Event Horizon Telescope (EHT) at 230 GHz, including the phased Atacama Large Millimeter/submillimeter Array (ALMA), at an angular resolution of ∼20uarcsec (at a redshift of z=0.536 this corresponds to ∼0.13pc, ∼1700 Schwarzschild radii with a black hole mass MBH=8x108M). Imaging and model-fitting techniques were applied to the data to parameterize the fine-scale source structure and its variation. We find a multicomponent inner jet morphology with the northernmost component elongated perpendicular to the direction of the jet, as imaged at longer wavelengths. The elongated nuclear structure is consistent on all four observing days and across different imaging methods and model-fitting techniques, and therefore appears robust. Owing to its compactness and brightness, we associate the northern nuclear structure as the VLBI "core". This morphology can be interpreted as either a broad resolved jet base or a spatially bent jet. We also find significant day-to-day variations in the closure phases, which appear most pronounced on the triangles with the longest baselines. Our analysis shows that this variation is related to a systematic change of the source structure. Two inner jet components move non-radially at apparent speeds of ∼15c and ∼20c (∼1.3 and ∼1.7uarcsec/day, respectively), which more strongly supports the scenario of traveling shocks or instabilities in a bent, possibly rotating jet. The observed apparent speeds are also coincident with the 3C 279 large-scale jet kinematics observed at longer (cm) wavelengths, suggesting no significant jet acceleration between the 1.3mm core and the outer jet. The intrinsic brightness temperature of the jet components are ≲1010K, a magnitude or more lower than typical values seen at ≥7mm wavelengths. The low brightness temperature and morphological complexity suggest that the core region of 3C279 becomes optically thin at short (mm) wavelengths. Description: We release a data set to accompany the "First 3C279 Event Horizon Telescope Results" paper (Kim et al. 2020). The data set is derived from the Science Release 1 (SR1) of the Event Horizon Telescope (EHT)'s April 2017 observation campaign (EHTC et al. 2019ApJ...875L...3E). This data set contains 3C279 data for both low and high bands for all observed days (April 5th, 6th, 10th, 11th, 2017). Data from the 2017 observations were processed through three independent reduction pipelines (Blackburn et al., 2019ApJ...882...23B, Janssen et al., 2019A&A...626A..75J, EHTC et al. 2019ApJ...875L...3E). This release includes the fringe fitted, a-priori calibrated, and network calibrated data from the EHT-HOPS pipeline, which is the primary data set for the First 3C279 EHT results. Independent flux calibration is performed based on estimated station sensitivities during the campaign (Issaoun et al., 2017, EHT Memo 2017-CE-02, Janssen et al. 2019A&A...626A..75J,). A description of the data properties, their validation, and estimated systematic errors is given in EHTC et al. (2019ApJ...875L...3E) with additional details in Wielgus et al. (2019, https://eventhorizontelescope.org/for-astronomers/memos). The data are time averaged to 10 seconds and frequency averaged over all 32 intermediate frequencies (IFs). All polarization information is explicitly removed. To make the resulting 'uvfits' files compatible with popular very-long-baseline interferometry (VLBI) software packages, the circularly polarized cross-hand visibilities 'RL' and 'LR' are set to zero along with their errors, while parallel-hands 'RR' and 'LL' are both set to an estimated Stokes I value. Measurement errors for 'RR' and 'LL' are each set to sqrt(2) times the statistical errors for Stokes I. All uvfits files are located in the "uvfits/" subdirectory. Easy-to-read csv and txt files are derived from the uvfits files and provided in "csv" and "txt", respectively. Scripts that generate these files from the original SR1 data are also included. Finally, the run.sh script in the top directory will convert uvfits files into csv and txt files. The three tgz files are gzipped tarballs that contains uvfits, txt, and csv files, respectively. They are included in this repository for convenience. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 66 8 List of tables, in tables subdirectory tables/* 98 8 Tables in ascii format INVENTORY.txt 55 42 Inventory LICENSE.txt 78 680 License README.md 136 74 ReadMe run.sh 72 26 run program csv/* 0 9 Tables in csv format tgz/* 0 3 tgz files are gzipped tarballs that contains uvfits, txt, and csv files txt/* 0 9 Tables in txt format uvfits/* 0 9 Tables in uvfits format
Byte-by-byte Description of file: list.dat
Bytes Format Units Label Explanations
1- 5 A5 --- Source [3C279] Source 7- 11 I5 d MJD Modified Julian date 13- 20 F8.4 GHz Freq Frequency 22- 66 A45 --- FileName Name of the file in subdirectory tables
Byte-by-byte Description of file: tables/*
Bytes Format Units Label Explanations
1- 11 F11.8 d Time Time (UTC) 18- 19 A2 --- T1 Station 1 (1) 25- 26 A2 --- T2 Station 2 (1) 29- 44 F16.4 --- U(lambda) U wavelength 47- 62 F16.4 --- V(lambda) V wavelength 65- 74 F10.8 Jy Iamp Stokes I flux-calibrated visibility amplitude 78- 86 F9.4 d Iphase Stokes I phase 89- 98 F10.8 Jy Isigmaa Stokes I error
Note (1): Station code as follows: AA = ALMA, Chile AP = APEX, Chile AZ = Submillimeter Telescope, Arizona JC = James Clerk Maxwell Telescope, Hawaii LM = Large Millimeter Telescope, Mexico PV = IRAM, Spain SM = Submillimeter Array, Hawaii SP = South Pole Telescope, South Pole
Acknowledgements: Jae-Young Kim, jykim(at)mpifr-bonn.mpg.de References: EHT Collaboration Data Portal Website, https://eventhorizontelescope.org/for-astronomers/data Issaoun, S., Folkers, T., Blackburn, L., et al. 2017, EHT Memo 2017-CE-02, https://eventhorizontelescope.org/for-astronomers/memos Janssen, M., Blackburn, L., Issaoun, S., et al. 2019, EHT Memo 2019-CE-01, https://eventhorizontelescope.org/for-astronomers/memos Wielgus, M., Blackburn, L., Issaoun, S., et al. 2019, EHT Memo 2019-CE-02, https://eventhorizontelescope.org/for-astronomers/memos
(End) Jae-Young KIM [MPIfR, Germany], Patricia Vannier [CDS] 13-Jul-2020
The document above follows the rules of the Standard Description for Astronomical Catalogues; from this documentation it is possible to generate f77 program to load files into arrays or line by line

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