Swift catches Changing Look AGN IRAS 23226-3843 in outburst
ATel #13182; Dirk Grupe (Morehead State University), S. Komossa (MPIfR), Norbert Schartel (ESAC), Michael Parker (ESAC), Wolfram Kollatschny (U. Goettingen), Martin W. Ochmann (U. Goettingen), & Encarni Romero Colmenero (SAAO)
on 11 Oct 2019; 17:11 UT
Credential Certification: Dirk Grupe (dgrupe007@gmail.com)
Subjects: Optical, Ultra-Violet, X-ray, AGN
We report on a dramatic increase in the X-ray and UV fluxes discovered by Swift in the changing-look AGN IRAS 23226-3843. While over the last decade the X-ray and UV-luminosities of IRAS 23226-3843 were constantly declining, in a guest investigator fillin program Swift found on 2019 August 11 that its X-ray flux had increased by a factor about 40 compared with observations obtained two years earlier. In the UV, IRAS 23226-3843 made a jump by more than 2 magnitudes. On August 11, we measured an absorption-corrected X-ray flux of 1.18e-14 W/m^2 (0.3-10 keV) and a W2 magnitude of 14.47 (Vega system, corrected for Galactic reddening).
In the most recent Swift observation from 2019 October 05 the absorption corrected X-ray flux in the 0.3-10 keV band was 1.4e-14 W/m^2. The reddening-corrected UVOT magnitudes in B, U, W1, and W2 (in the Vega system, uncorrected values in parenthesis) were: B=15.52+/-0.05 (15.63), U=14.89+/-0.06 (15.03), W1=14.69+/-0.06 (14.86), and W2=14.56+/-0.08 (14.77).
Recent optical spectroscopy obtained by the South African Large Telescope (SALT) confirms the increase in the optical flux as well as a significant increase in the broad permitted emission lines. This indicates a change in the optical Seyfert type of IRAS 23226-3843 again.
We continue monitoring IRAS 23226-3843 with Swift. Also follow-up observations with XMM-Newton and NuSTAR are planned. We would like to thank Brad Cenco for approving our monitoring campaign and the Swift team for a prompt execution of the program.
