2016ApJ...820...90F

Query : 2016ApJ...820...90F

2016ApJ...820...90F - Astrophys. J., 820, 90 (2016/April-1)

Persistent asymmetric structure of Sagittarius A* on event horizon scales.

FISH V.L., JOHNSON M.D., DOELEMAN S.S., BRODERICK A.E., PSALTIS D., LU R.-S., AKIYAMA K., ALEF W., ALGABA J.C., ASADA K., BEAUDOIN C., BERTARINI A., BLACKBURN L., BLUNDELL R., BOWER G.C., BRINKERINK C., CAPPALLO R., CHAEL A.A., CHAMBERLIN R., CHAN C.-K., CREW G.B., DEXTER J., DEXTER M., DZIB S.A., FALCKE H., FREUND R., FRIBERG P., GREER C.H., GURWELL M.A., HO P.T.P., HONMA M., INOUE M., JOHANNSEN T., KIM J., KRICHBAUM T.P., LAMB J., LEON-TAVARES J., LOEB A., LOINARD L., MacMAHON D., MARRONE D.P., MORAN J.M., MOSCIBRODZKA M., ORTIZ-LEON G.N., OYAMA T., OZEL F., PLAMBECK R.L., PRADEL N., PRIMIANI R.A., ROGERS A.E.E., ROSENFELD K., ROTTMANN H., ROY A.L., RUSZCZYK C., SMYTHE D.L., SOOHOO J., SPILKER J., STONE J., STRITTMATTER P., TILANUS R.P.J., TITUS M., VERTATSCHITSCH L., WAGNER J., WARDLE J.F.C., WEINTROUB J., WOODY D., WRIGHT M., YAMAGUCHI P., YOUNG A., YOUNG K.H., ZENSUS J.A. and ZIURYS L.M.

Abstract (from CDS):

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 general relativistic shadow. Previous EHT observations have used visibility amplitudes to infer the morphology of the millimeter-wavelength emission. Potentially much richer source information is contained in the phases. We report on 1.3 mm phase information on Sgr A* obtained with the EHT on a total of 13 observing nights over four years. Closure phases, which are the sum of visibility phases along a closed triangle of interferometer baselines, are used because they are robust against phase corruptions introduced by instrumentation and the rapidly variable atmosphere. The median closure phase on a triangle including telescopes in California, Hawaii, and Arizona is nonzero. This result conclusively demonstrates that the millimeter emission is asymmetric on scales of a few Schwarzschild radii and can be used to break 180° rotational ambiguities inherent from amplitude data alone. The stability of the sign of the closure phase over most observing nights indicates persistent asymmetry in the image of Sgr A* that is not obscured by refraction due to interstellar electrons along the line of sight.

Abstract Copyright: ∼

Journal keyword(s): Galaxy: center - submillimeter: general - techniques: high angular resolution - techniques: interferometric

VizieR on-line data: <Available at CDS (J/ApJ/820/90): table2.dat>

Simbad objects: 7

Full paper

View the references in ADS

Number of rows : 7

N	Identifier	Otype	ICRS (J2000) RA	ICRS (J2000) DEC	Mag U	Mag B	Mag V	Mag R	Mag I	Sp type	#ref 1850 - 2026	#notes
1	M 87	AGN	12 30 49.42338414	+12 23 28.0436859	10.16	9.59	8.63		7.49	~	7815	3
2	3C 279	Bla	12 56 11.16657958	-05 47 21.5251510		18.01	17.75	15.87		~	3205	2
3	NAME Galactic Center	reg	17 45 39.60213	-29 00 22.0000						~	16269	0
4	NAME Sgr A*	X	17 45 40.03599	-29 00 28.1699						~	4970	3
5	NAME G2 Dust Cloud	IR	17 45 40.04	-29 00 28.1						~	209	0
6	NAME Sgr A*-f	Cld	17 45 40.04	-29 00 28.1						~	59	1
7	NAME BL Lac	BLL	22 02 43.2913536816	+42 16 39.979416792		15.66	14.72			~	2397	1

To bookmark this query, right click on this link: simbad:objects in 2016ApJ...820...90F and select 'bookmark this link' or equivalent in the popup menu