J/MNRAS/493/L81 Radio astrometry of MAXI J1820+070 (Atri+, 2020)
A radio parallax to the black hole X-ray binary MAXI J1820+070.
Atri P., Miller-Jones J.C.A., Bahramian A., Plotkin R.M., Deller A.T.,
Jonker P.G., Maccarone T.J., Sivakoff G.R., Soria R., Altamirano D.,
Belloni T., Fender R., Koerding E., Maitra D., Markoff S., Migliari S.,
Russell D., Russell T., Sarazin C.L., Tetarenko A.J., Tudose V.
<Mon. Not. R. Astron. Soc., 493, L81 (2020)>
=2020MNRAS.493L..81A 2020MNRAS.493L..81A (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, X-ray ; Positional data ; Parallaxes, spectroscopic
Keywords: astrometry - parallaxes - stars: black holes -
radio continuum: transients - X-rays: binaries -
high angular resolution
Abstract:
Using the Very Long Baseline Array and the European Very Long Baseline
Interferometry Network, we have made a precise measurement of the
radio parallax of the black hole X-ray binary MAXI J1820+070,
providing a model-independent distance to the source. Our parallax
measurement of (0.348±0.033) mas for MAXI J1820+070 translates to a
distance of (2.96±0.33)kpc. This distance implies that the source
reached (15±3) per cent of the Eddington luminosity at the peak of
its outburst. Further, we use this distance to refine previous
estimates of the jet inclination angle, jet velocity, and the mass of
the black hole in MAXI J1820+070 to be (63±3)°, (0.89±0.09)c,
and (9.2±1.3)M☉, respectively
Description:
We monitored MAXI-J1820 (see Table 1) with the Very Long Baseline
Array (VLBA), using both the Jet Acceleration and Collimation Probe of
Transient X-ray Binaries (JACPOT-XRB) programme, proposal code BM467),
and a long-running astrometry programme (proposal code BA130),
supplemented with a targeted European VLBI Network (EVN) campaign
(proposal code EA062). All observations used a combination of
J1821+0549 (J1821 hereon) and J1813+065 (J1813 hereon) as the phase
reference and astrometric check sources. The calibrator positions were
taken from the Radio Fundamental catalogue (rfc2015a1). Our assumed
positions (J2000) were
RA = 18:21:27.305837, Dec = 05:49:10.65156 for J1821, and
RA = 18:13:33.411619, Dec = 06:15:42.03366 for MAXI J1813.
We imaged the calibrated data and determined the target position by
fitting a point source in the image plane for every epoch.
Objects:
------------------------------------------------------------------------
RA (2000) DE Designation(s)
------------------------------------------------------------------------
18 20 21.9384568 +07 11 07.001649624 MAXI-J1820+070 = MAXI J1820+070
------------------------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 116 11 Summary of the observations of MAXI-J1820+070.
table2.dat 118 1 Astrometric details of the black hole X-ray
binary MAXI J1820+070
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Code Project code
9- 16 F8.2 d MJD Date
19- 22 A4 --- Array Array
24- 25 I2 GHz Freq [5/15] Frequency (1)
28- 39 A12 --- Cal Phase calibrator
42- 53 A12 --- Check Check source
55- 56 I2 h RAh Right ascension (J2000)
58- 59 I2 min RAm Right ascension (J2000)
61- 70 F10.7 s RAs Right ascension (J2000)
72- 80 F9.7 s e_RAs rms uncertainty on RA
82- 83 I2 deg DEd Declination (J2000)
85- 86 I2 arcmin DEm Declination (J2000)
88- 96 F9.6 arcsec DEs Declination (J2000)
98-105 F8.6 arcsec e_DEs rms uncertainty on DE
107-111 F5.2 mJy/beam Ipeak Peak intensity in Freq
113-116 F4.2 mJy/beam e_Ipeak Peak intensity in Freq error
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Note (1): The observing bandwidth was 32MHz for both the VLBA and the EVN.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Name
16- 17 I2 h RAh Right ascension (J2000)
19- 20 I2 min RAm Right ascension (J2000)
22- 31 F10.7 s RAs Right ascension (J2000)
33- 41 F9.7 s e_RAs Error on RA
43- 44 I2 deg DEd Declination (J2000)
46- 47 I2 arcmin DEm Declination (J2000)
49- 60 F12.9 arcsec DEs Declination (J2000)
62- 71 F10.8 arcsec e_DEs Error on DE (J2000)
72- 77 F6.3 mas/yr pmRA Proper motion along RA
79- 83 F5.3 mas/yr e_pmRA Proper motion along RA error
85- 90 F6.3 mas/yr pmDE Proper motion along DE
92- 96 F5.3 mas/yr e_pmDE Proper motion alond DE error
98-102 F5.3 mas plx Radio_parallax
104-108 F5.3 mas e_plx Error in the radio parallax
110-113 F4.2 kpc Dist Distance of the target from the radio parallax
115-118 F4.2 kpc e_Dist Error on the distance of the target from
the radio parallax
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Acknowledgements:
Pikky Atri, pikkyatri23(at)gmail.com
(End) Patricia Vannier [CDS] 28-Sep-2022