Aql X-1: a new outburst is in progress
ATel #13020; O. I. Spiridonova, V. V. Vlasyuk, A. S.Moskvitin, O. A.Maslennikova, R. I.Uklein (Special Astrophysical Observatory of the Rus. Ac. Sci.)
on 13 Aug 2019; 11:00 UT
Credential Certification: Alexander Moskvitin (mosk@sao.ru)
Subjects: Optical, Transient
Referred to by ATel #: 13953
Within a course of optical monitoring campaign of Soft X-ray Transient (SXT) Aql X-1 performed with the 1-m SAO RAS optical telescope in June-August we have detected indications on start a new outburst. According to our preliminary results in R-band, it's brightness increased between first decades of July and August. Our estimates of brightness of Aql X-1 optical counterpart in R-band in May-June were between 18.1 and 18.5 mag. Meanwhile, R-magnitude for epochs after July 4th demonstrated some trend for increasing, as seen in Table.
| Date | JD | R_mag |
|---|
| 20190704 | 2458669.4 | 18.05 |
| 20190806 | 2458702.4 | 17.00 |
| 20190807 | 2458703.2 | 16.90 |
| 20190811 | 2458707.4 | 16.70 |
Typical errors of brightness estimates are about 0.05 mag and should be decreased after more accurate data reduction. Measurements at August, 11 were obtained with midband filter and had some worse accuracy due to bright sky background (about 0.1 mag). Further observations of Aql X-1 in X-ray, UV, Optical, IR and Radio ranges are highly encouraged.
