New black hole binary in outburst (Mag 12.5 in Oph)
Posted: Sat Mar 17, 2018 7:16 am
MAXI J1820+070 is a new X-ray transient discovered on 2018 March 11 12:50
UT by MAXI (ATel #11399)
It has been associated with a bright optical transient
ASASSN-18ey (ATel #11400) in Ophiucus.
AD (2000) : 18 20 21.95
DE (2000) : +07 11 07.3
The observations show rapid brightening, fast optical variability.
Current magnitude (V) = 12.5
The observations are consistent with a black hole X-ray binary in the hard state
Optical spectra show
strong, broad H-alpha emission
and weaker emission from He I 5875 and the Bowen blend.
The H-alpha has a FWHM of about 1150 km/s. It is asymmetric but not clearly double-peaked
This FWHM is relatively low for a black hole X-ray transient,
suggesting either that the system has a long period associated with an evolved donor or that it is relatively face-on.
here are no obvious absorption features in the spectrum, indicating that continuum is dominated by the accretion disk.
(ATel #11424)
presence of a broad, asymmetric H-alpha emission line
Also detected broad H-beta, H-gamma, and H-delta absorption with emission lines in the center,
characteristic of an accretion disk in outburst.
He II 4686 (with EW = -1.7 Ang) is seen on top of the continuum
(ATel #11425)
Spectroscopy of MAXI J1820+070 is strongly encouraged.
An ideal target in the morning sky for Alpy, LISA and other low resolution spectroscopes
Observations will help to understand the intriguing nature of this source
Spectra will be added to ARAS Eruptive stars database
Send spectra to francoismathieu.teyssier at bbox.fr for inclusion in the database
Use MAXI J1820+70 in the fit header
François Teyssier
UT by MAXI (ATel #11399)
It has been associated with a bright optical transient
ASASSN-18ey (ATel #11400) in Ophiucus.
AD (2000) : 18 20 21.95
DE (2000) : +07 11 07.3
The observations show rapid brightening, fast optical variability.
Current magnitude (V) = 12.5
The observations are consistent with a black hole X-ray binary in the hard state
Optical spectra show
strong, broad H-alpha emission
and weaker emission from He I 5875 and the Bowen blend.
The H-alpha has a FWHM of about 1150 km/s. It is asymmetric but not clearly double-peaked
This FWHM is relatively low for a black hole X-ray transient,
suggesting either that the system has a long period associated with an evolved donor or that it is relatively face-on.
here are no obvious absorption features in the spectrum, indicating that continuum is dominated by the accretion disk.
(ATel #11424)
presence of a broad, asymmetric H-alpha emission line
Also detected broad H-beta, H-gamma, and H-delta absorption with emission lines in the center,
characteristic of an accretion disk in outburst.
He II 4686 (with EW = -1.7 Ang) is seen on top of the continuum
(ATel #11425)
Spectroscopy of MAXI J1820+070 is strongly encouraged.
An ideal target in the morning sky for Alpy, LISA and other low resolution spectroscopes
Observations will help to understand the intriguing nature of this source
Spectra will be added to ARAS Eruptive stars database
Send spectra to francoismathieu.teyssier at bbox.fr for inclusion in the database
Use MAXI J1820+70 in the fit header
François Teyssier