Variability of infrared object 2MASS 18342090-0559425 close to the flaring water maser G025.65+1.05
ATel #10788; Sobolev A. M., Bisyarina A. P. (UrFU), Tatarnikov A. M., Antokhin I. (SAI MSU), Volvach A. E. (Crimean Astrophysical Observatory)
on 27 Sep 2017; 16:17 UT
Credential Certification: Alexandr Volvach (email@example.com)
Subjects: Infra-Red, Transient, Variables, Young Stellar Object
Near infrared K image of vicinity of the flaring water maser source (Volvach and Volvach, et al. 2017, ATel #10728; Koichiro Sugiyama, Yu Saito, et al. 2017, ATel #10757) was obtained on 2017-09-21 with 2.5m telescope at Caucasian Mountain Observatory (CMO) of Sternberg Astronomical Institute. Comparison with K images obtained in UKIDSS survey on 2007-08-27 and 2011-09-18 shows that the source 2MASS 18342090-0559425 on 2017-09-21 has greatly reduced brightness in comparison to the epochs of UKIDSS observations. This near infrared source is located 1.5" south-east of the maser source and the image shows signs of their association.
In the CMO image 18342090-0559425 is substantially weaker than the nearby source 18342090-0559458 which shows rather stable brightness in all K images with respect to the nearby sources of comparable K brightness, e.g. 18342453-0558599 and 18342125-0559474. In contrast, in the UKIDSS images 18342090-0559425 is substantially brighter than 18342090-0559458.
We conclude that variability of the source 2MASS 18342090-0559425 is the cause of variability of associated water and methanol masers. At the date of CMO observations flux of the flaring water maser was reduced to ~15 000 Jy.