Open AccessEvidence for a 2‐h optical modulation in GS 1826 – 24
Author(s) -
Homer L.,
Charles P. A.,
O'Donoghue D.
Publication year - 1998
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1998.01656.x
Subject(s) - physics , astrophysics , modulation (music) , context (archaeology) , neutron star , orbital period , amplitude , transient (computer programming) , astronomy , optics , stars , paleontology , acoustics , biology , computer science , operating system
We report the discovery of a 2.1‐h optical modulation in the transient source GS 1826 – 24, based on two independent, high‐time‐resolution photometric observing runs. There is additional irregular variability on shorter time‐scales. The source also exhibited an optical burst during each observation, with peak fluxes consistent with those of the three X‐ray bursts so far detected by BeppoSAX . We compare the low‐amplitude variation (∼ 0.06 mag) to that seen on the orbital periods of the short‐period X‐ray bursters, X1636−536 and X1735−444, as well as the similarity in their non‐periodic fluctuations. Other transient neutron star LMXBs possess short periods in the range 3.8–7.1 h. However, if confirmed as the orbital, a 2.1‐h modulation would make GS 1826 – 24 unique and therefore of great interest within the context of LMXB formation and evolution.