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ATEL # 3020; Blesson Mathew, Sachindra Naik, N. M. Ashok, S. V. Vadawale, D. P. K. Banerjee (Physical Research Laboratory, Navarangpura, Ahmedabad, India)
on 10 Nov 2010; 8:36 UT
Password Certification: Sachindra Naik (email@example.com)
Subjects: Infra-Red, Optical, X-ray, Binaries, Pulsars, Transients
Following the report of increase in the X-ray flux of the Be/X-ray binary pulsar A0535+262 since 2010 October 14 (Atel #2970), the photometric and spectroscopic observations were carried out in near-infrared J, H, and K-bands on 2010 October 28.9 UT and 31.9 UT using the 1.2 m Mt. Abu telescope operated by Physical Research Laboratory, Ahmedabad, India. The J, H, and K magnitudes of the Be star were estimated to be 7.69+/-0.02, 7.63+/-0.03 and 7.42+/-0.02 on 28 October 2010, and marginally brighter at 7.61+/-0.03, 7.50+/-0.02, and 7.40+/-0.02 on 31 October 2010 respectively. The increase in X-ray flux in October 2010 (peak flux of ~6 ASM counts/s on 24 October 2010; 1 Crab = 74 counts/s) was not significant compared to the outburst observed in March-April 2010 (peak flux of ~26 ASM counts/s on 6 April 2010). Our spectroscopic observations during the March-April 2010 outburst (on March 28.6 UT) and October 2010 outburst showed that the HI and HeI emission lines seen in J, H, and K-band spectra on 2010 March 28 are also present in the spectra on 2010 October 31. However, the emission lines are less prominent during the October 2010 outburst. Further monitoring of the source will be carried out from Mt. Abu observatory.