[Date Prev][Date Next][Date Index]

(cba:news) ASASSN-18ey = MAXI J1820+070 (Joe Patterson) [2018-05-05T19:33:15Z]


Hi CBAers,

Some of you probably saw the ATEl that Michael Richmond and Stephen Brincat sent out, reporting, among other things, a 3.4 hour period in the light curve of this still crazy-bright X-ray (presumably black-hole) transient. Origin unknown, but let's jump in and figure it out! All longitudes and latitudes and lassitudes invited.

As usual, long (3+ hours) coverage will have greatest impact. But all the data show a point-to-point scatter far greater than the error of measurement. This means that there is considerable source variation on timescales of just a few seconds - basically unlike CVs, which are considerably fonder of timescales around *minutes*, not *seconds*. We found a similar thing years ago: a 6-second QPO in our study of 1118+48, another black-hole transient. So as long as the source is bright (now 12.5) and assuming your measurement error can tolerate it, keep the integrations short! (Can't be any more quantitative than that, since we don't actually know the timescale).

I certainly recommend this guy as #1 priority. Some of you are doing a great job with AM CVn, and our many-month coverage of it will have great impact. But old Maxie has highest priority whenever it's above 2 airmasses - certainly at non-USA longitudes, and I'd say at USA also.

joe p

____________________________________________________________
Center for Backyard Astrophysics (CBA) mailing lists
https://cbastro.org/communications/mailing-lists/