X-RAY AND OPTICAL OBSERVATIONS OF A 0535+26

Journal Article · Fri Jul 20 04:00:00 EDT 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/754/1/20· OSTI ID:22039332

Camero-Arranz, A; Finger, M H ^[1]; Wilson-Hodge, C A; Jenke, P ^[2]; Steele, I ^[3]; Coe, M J; McBride, V A ^[4]; Gutierrez-Soto, J ^[5]; Kretschmar, P ^[6]; Caballero, I; Rodriguez, J ^[7]; Yan, J ^[8]; Suso, J ^[9]; Case, G; Cherry, M L ^[10]; Guiriec, S ^[11]

---

1. Universities Space Research Association, Huntsville, AL 35806 (United States)
2. Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States)
3. Liverpool J. Moore's University, Kingsway House, Hatton Garden, Liverpool L3 2AJ (United Kingdom)
4. University of Southampton, University Road, Southampton SO17 1BJ (United Kingdom)
5. Instituto de Astrofisica de Andalucia, Glorieta de la Astronomia, s/n, E-18008, Granada (Spain)
6. ESA/ESAC, Madrid (Spain)
7. AIM-CEA Saclay, Paris (France)
8. Purple Mountain Observatory, Chinese Academy of Sciences, Beijing (China)
9. University of Valencia, Poligono de la Coma, s/n, 46980 Paterna (Spain)
10. Louisiana State University, Boton Rouge, LA 70803 (United States)
11. NASA GSFC, Greenbelt, MD 20771 (United States)

We present recent contemporaneous X-ray and optical observations of the Be/X-ray binary system A 0535+26 with the Fermi/Gamma-ray Burst Monitor (GBM) and several ground-based observatories. These new observations are put into the context of the rich historical data (since {approx}1978) and discussed in terms of the neutron-star-Be-disk interaction. The Be circumstellar disk was exceptionally large just before the 2009 December giant outburst, which may explain the origin of the unusual recent X-ray activity of this source. We found a peculiar evolution of the pulse profile during this giant outburst, with the two main components evolving in opposite ways with energy. A hard 30-70 mHz X-ray quasi-periodic oscillation was detected with GBM during this 2009 December giant outburst. It becomes stronger with increasing energy and disappears at energies below 25 keV. In the long term a strong optical/X-ray correlation was found for this system, however in the medium term the H{alpha} equivalent width and the V-band brightness showed an anti-correlation after {approx}2002 August. Each giant X-ray outburst occurred during a decline phase of the optical brightness, while the H{alpha} showed a strong emission. In late 2010 and before the 2011 February outburst, rapid V/R variations are observed in the strength of the two peaks of the H{alpha} line. These had a period of {approx}25 days and we suggest the presence of a global one-armed oscillation to explain this scenario. A general pattern might be inferred, where the disk becomes weaker and shows V/R variability beginning {approx}6 months following a giant outburst.

• OSTI ID: 22039332
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 754; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCRETION DISKS
ASTROPHYSICS
BINARY STARS
BRIGHTNESS
CORRELATIONS
COSMIC GAMMA BURSTS
GAMMA ASTRONOMY
KEV RANGE
MHZ RANGE
NEUTRON STARS
OSCILLATIONS
PERIODICITY
PULSARS
PULSES
X RADIATION