@article{10272/18416,
year = {2017},
month = {8},
url = {http://hdl.handle.net/10272/18416},
abstract = {Context. Based on XMM-Newton X-ray observations IGR J19552+0044 appears to be either a pre-polar or an asynchronous polar.
Aims. We conducted follow-up optical observations to identify the sources and periods of variability precisely and to classify this
X-ray source correctly.
Methods. Extensive multicolor photometric and medium- to high-resolution spectroscopy observations were performed and period
search codes were applied to sort out the complex variability of the object.
Results. We found firm evidence of discording spectroscopic (81.29 ± 0.01 m) and photometric (83.599 ± 0.002 m) periods that
we ascribe to the white dwarf (WD) spin period and binary orbital period, respectively. This confirms that IGR J19552+0044 is
an asynchronous polar. Wavelength dependent variability and its continuously changing shape point at a cyclotron emission from a
magnetic WD with a relatively low magnetic field below 20 MG.
Conclusions. The difference between the WD spin period and the binary orbital period proves that IGR J19552+0044 is a polar with
the largest known degree of asynchronism (0.97 or 3%).},
publisher = {EDP Sciences},
keywords = {Accretion},
keywords = {Accretion disks},
keywords = {Magnetic field},
title = {IGR J19552+0044: A new asynchronous short period polar Filling the gap between intermediate and ordinary polars},
doi = {10.1051/0004-6361/201731323},
author = {Tovmassian, G. and González Buitrago, D. and Thorstensen, J. R. and Miguel Agustino, Enrique de},
}