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Aql X-1 outburst in Optical/IR/X-rays

ATel #288; D. Maitra, C. Bailyn, R. Winnick (Yale), J. Espinoza, D. Gonzalez (CTIO/SMARTS)
on 27 May 2004; 23:12 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Dipankar Maitra (maitra@astro.yale.edu)

Subjects: Infra-Red, Optical, Binary, Neutron Star, Transient

Daily optical/IR imaging of Aql X-1 by the SMARTS consortium using the ANDICAM instrument on the 1.3m telescope confirm the high optical state reported by Ilovaisky and Chevalier (ATEL #287).

Around 11th May 2004 the O/IR began a strong rise from a persistent intermediate state (with average magnitudes of R = 17.3 and J = 15.7), and then reached a peak near 25-26th May (at R = 16.3 and J = 14.6)and now is declining again. The present R band optical flux is near 16.6 mag and infrared J flux near 14.8 mag. Our RXTE/PCA peliminary results show that the soft X-ray flux has been increasing as well, accompanied by frequent type I bursts. Four type I bursts were seen in RXTE pointings between 23rd and 26th May. Frequent Type I bursts observed during previous outbursts of Aql X-1 suggest that the source might soon make a transition to soft state (if it has not already done so).

Most recent O/IR/X-ray lightcurve of Aql X-1 (O/IR data from SMARTS, X-ray data from publicly available RXTE/ASM archive)