New black hole binary in outburst (Mag 12.5 in Oph)

Information about outbursts of eruptive stars, Be activity, ...
Francois Teyssier
Posts: 1520
Joined: Fri Sep 23, 2011 1:01 pm
Location: Rouen
Contact:

New black hole binary in outburst (Mag 12.5 in Oph)

Post by Francois Teyssier »

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
Forrest Sims
Posts: 86
Joined: Thu Feb 09, 2017 5:52 pm

Re: New black hole binary in outburst (Mag 12.5 in Oph)

Post by Forrest Sims »

Greetings!

Spectrum data from last night for MAXI J1820+70 also now apparently known as ASASSN-18ey.

This was tricky catching it after the clouds cleared away and before dawn. This target stood out quite brightly in the place predicted by the AAVSO Chart. I was able to get 6 usable 300sec exposures of the Target before the sky background became too strong. I took 7 30 second images of the A0III Reference star HD181470 for creating the Response curve correction. This target would certainly have benefited from longer exposures if time had allowed.

Thanks
Woody
Attachments
maxij1820+70_20180321_514_Forrest Sims.png
Francois Teyssier
Posts: 1520
Joined: Fri Sep 23, 2011 1:01 pm
Location: Rouen
Contact:

Re: New black hole binary in outburst (Mag 12.5 in Oph)

Post by Francois Teyssier »

That's excellent, Woody
Typical spectrum of a dwarf nova in outburst
It could be a polar, according to Steve
Robin Leadbeater
Posts: 1926
Joined: Mon Sep 26, 2011 4:41 pm
Contact:

Re: New black hole binary in outburst (Mag 12.5 in Oph)

Post by Robin Leadbeater »

A professional spectrum has just been posted on TNS by the ePESSTO team
https://wis-tns.weizmann.ac.il/object/2018amn

Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Forrest Sims
Posts: 86
Joined: Thu Feb 09, 2017 5:52 pm

Re: New black hole binary in outburst (Mag 12.5 in Oph)

Post by Forrest Sims »

Here is my data from this morning on ASASSN-18ey = MAXI J1820+070. According to the AAVSO Alert notice 630 there is a "blitz" campaign for two nights (thru 13 April) on this object. They want high cadence photometry. But maybe some 600sec images of the spectrum would be of interest.

Cheers!
Woody
Attachments
asassn-18ey_20180412_438_Forrest Sims anotated.png
asassn-18ey_20180412_438_Forrest Sims anotated.png (36.6 KiB) Viewed 11930 times
Joan Guarro Flo
Posts: 611
Joined: Thu Nov 03, 2011 8:50 pm

Re: New black hole binary in outburst (Mag 12.5 in Oph)

Post by Joan Guarro Flo »

Good job Forrest !!

I can't was observed more on last days Nova CMa 2018, because it's cloudy and raining. Here the weather don't will better until next Sunday night.

Regards, Joan.
Peter Somogyi
Posts: 420
Joined: Sun Jul 13, 2014 8:56 am

Re: New black hole binary in outburst (Mag 12.5 in Oph)

Post by Peter Somogyi »

Hi Woody,

You have a nice and valuable serie!
Let me extend it with a fresh result of today's morning:
maxij1820+070_20180414_066_PSO.png
Conditions were good (target high enough), more of us should be able to follow.

Cheers,
Peter
Peter Somogyi
Posts: 420
Joined: Sun Jul 13, 2014 8:56 am

Re: New black hole binary in outburst (Mag 12.5 in Oph)

Post by Peter Somogyi »

Hello,

Seeing observers activity on this object again, revisited it the last Sunday morning:
maxij1820+070.png
maxij1820+070.png (104.72 KiB) Viewed 11516 times
The HeI lines have separated clearly.
Exposures info:
2018.04.14 (JD=2458222.5982): 9 x 600 sec
2018.05.05 (JD=2458244.4973): 5 x 1200 sec
2018.06.24 (JD=2458293.5516): 3 x 1200 sec (of 10 min clouds)

Peter
Peter Somogyi
Posts: 420
Joined: Sun Jul 13, 2014 8:56 am

Re: New black hole binary in outburst (Mag 12.5 in Oph)

Post by Peter Somogyi »

+ Forgot to add:
http://www.astronomerstelegram.org/?read=11756
=> https://cbastro.org/the-astronomers-telegram/2018-june/
=> [...] "The phase stability of the 0.703 d wave makes it a good candidate for the orbital period of the underlying compact binary, although other interpretations (superhump? precession?) are possible. Spectroscopic observation could test this hypothesis, and ascertain the dominant light source in the binary."

Of course, my summer time window + poor horizon access not enough to check this 0.703d. (I am suspecting the large continuum changes doing that.)
Perhaps someone else (or more of us - multiple nights) could do it.

Peter
James Foster
Posts: 439
Joined: Sun Jan 24, 2016 7:14 am

Re: New black hole binary in outburst (Mag 12.5 in Oph)

Post by James Foster »

Here is my best spectra of ASASSN-18ey taken from Mt. Pinos, CA last week with a LISA spectroscope on a 33cm aperture classical cassegrain reflector (1-Hr exposure):
Image
The O1 line at 5577A is terlluric. Only very noticeable lines are H-Alpha, H-Beta, & the He II(4685.7A).

James
James Foster
eShel2-Zwo ASI6200MM Pro
Lhires III (2400/1800/600 ln/mm Grat) Spectroscope
LISA IR/Visual Spectroscope (IR Configured)
Alpy 200/600 with Guide/Calibration modules and Photometric slit
Star Analyzer 200
Post Reply