Optical spectrophotometry of the new outburst from MAXI J1807+132
ATel #13118; N. Masetti & R. Gualandi (INAF-OAS, Bologna, Italy)
on 20 Sep 2019; 18:54 UT
Credential Certification: Nicola Masetti (masetti@iasfbo.inaf.it)
Subjects: Optical, Transient
Triggered by the recent reactivation of source MAXI J1807+132 in X-rays (ATel #13097) and radio (ATel #13107), we observed its optical counterpart with the 1.5m "Cassini" telescope (equipped with BFOSC) in Loiano, Italy.
A preliminary analysis of a 10-min V-band exposure acquired starting at 20:13 UT of Sep 19, 2019, shows the source at a magnitude V = 16.8+-0.1 according to the field calibration available at the AAVSO VSP. This indicates that the object presently has an activity level comparable to that in the second half of March 2017 (see ATel #10227).
Nearly-simultaneous optical spectroscopy (start time: 19:28 UT; exposure: 30 min; dispersion: 4.0 Angstroms/pixel) shows a smooth blue continuum with no evident intrinsic features, either in emission or absorption.
