REM observations of the blazar OJ 287 in NIR
ATel #4026; F. D'Ammando (Dip. Fisica, Univ. Perugia) , S. Covino (INAF-OA Brera), D. Fugazza (INAF-OA Brera), E. Molinari (INAF-IASFMI)
on 10 Apr 2012; 12:45 UT
Credential Certification: Filippo D'Ammando (filippo.dammando@iasf-roma.inaf.it)
Subjects: Infra-Red, AGN, Black Hole, Blazar
The robotic 60-cm REM telescope located at La Silla (Chile), following a periodical monitoring program, observed automatically the field of the blazar OJ 287 starting from November 2009. Recently, infrared observations were performed in the J and H bands using REMIR on 2012 April 5 and 7. The NIR magnitudes were calibrated against the 2MASS catalogue. Preliminary results are reported in the following table.
| Date-Obs | J_mag | H_mag |
| 29/02/12 | 13.01 +/- 0.03 | 12.28 +/- 0.07 |
| 05/04/12 | 12.28 +/- 0.01 | 11.51 +/- 0.02 |
| 07/04/12 | 12.57 +/- 0.02 | 11.76 +/- 0.03 |
REM observations show an increase in the source flux of about 0.7 magnitude in J band and H band on 2012 April 5 with respect to the observations of February 29, followed by a rapid decrease of about 0.25 mag in two days. These observations are in agreement with the optical behaviour reported by Santangelo (ATel #4020) and Chandra et al. (ATel #4021).
An increase of the source activity in NIR was already observed by REM in October 2011, with J = 12.46 +/- 0.09 and H = 11.67 +/- 0.09 (ATel #3682). REM will continue to monitor the source for our program in the following months.
