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 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 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 2019ApJ...882...23B, Janssen et al.,
2019A&A...626A..75J 2019A&A...626A..75J, EHTC et al. 2019ApJ...875L...3E 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 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 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/* . 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/* . 9 Tables in csv format
tgz/* . 3 tgz files are gzipped tarballs that contains
uvfits, txt, and csv files
txt/* . 9 Tables in txt format
uvfits/* . 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