Near-IR observations of the outbursting source ASASSN-18mw
ATel #11811; T. Giannini, F. Vitali,, D. Lorenzetti, S. Antoniucci (INAF - Osservatorio Astronomico di Roma, Monte Porzio, Italy), D. Licchelli (Universita' del Salento)
on 3 Jul 2018; 10:39 UT
Credential Certification: Teresa Giannini (teresa.giannini@inaf.it)
Subjects: Infra-Red, Cataclysmic Variable, Variables, Young Stellar Object
In the framework of our EXor monitoring programme dubbed EXORCISM (EXOR OptiCal and Infrared Systematic Monitoring - Antoniucci et al. 2013 PPVI, Lorenzetti et al. 2007 ApJ 665, 1182; Lorenzetti et al. 2009 ApJ 693, 1056), we observed in the near-IR the object ASASSN-18mw recently (June 17) signalled by an ASASSN alert as a possible EXOR candidate in outburst (see also ASASSN
transients at http://www.astronomy.ohio-state.edu/asassn/transients.html and AAVSO light-curve at https://www.aavso.org/LCGv2 ).
Our photometry has been obtained with the near infrared REMIR camera at the 60-cm robotic telescope REM located at La Silla (Chile):
| Date | J(mag) | H(mag) |
| 2018.06.21 | 15.9±0.4 | 15.3±0.3 |
| 2018.06.22 | 15.9±0.6 | -- |
| 2018.06.23 | 16.3±0.5 | -- |
Compared with the limiting magnitudes due to our small telescope, the source was very faint, nevertheless a decreasing flux density for increasing wavelengths is recognizable; such a trend is more typical of cataclysmic variables (Hoard et al. 2014 ApJ, 786, 68) than of young eruptive variables (Lorenzetti et al. 2012, ApJ, 749,188). Hence, we confirm the later adjustment provided by ASAS-SN team ("spectrum taken suggests this object is a CV") aimed at correcting their automatic classification.
Moreover, the position of ASAS-SN-18mw (far from known star-forming region) is a further indication that this source is probably not a YSO.
