INTEGRAL and RXTE monitoring of XTE J1817-330: evolving through a state change?

E. Kuulkers; P. Goldoni; S. E. Shaw; S. Brandt; J. Chenevez; T. J.-L. Courvoisier; K. Ebisawa; P. Kretschmar; C. Markwardt; N. Mowlavi; T. Oosterbroek; A. Orr; A. Paizis; J. Rodriguez; C. Sanchez-Fernandez; R. Wijnands

INTEGRAL and RXTE monitoring of XTE J1817-330: evolving through a state change?

E. Kuulkers^*, P. Goldoni, S. E. Shaw, S. Brandt, J. Chenevez, T. J.-L. Courvoisier, K. Ebisawa, P. Kretschmar, C. Markwardt, N. Mowlavi, T. Oosterbroek, A. Orr, A. Paizis, J. Rodriguez, C. Sanchez-Fernandez, R. Wijnands

^*Corresponding author for this work

National Space Institute

Research output: Other contribution › Net publication - Internet publication › Research

Abstract

INTEGRAL Galactic Bulge monitoring observations (ATel #438) indicate that the X-ray transient and black-hole candidate XTE J1817-330 (ATel #714) has increased in hard X-rays (20-60 keV) compared to the observations performed on Feb 9, 2006 (ATel #731). The 20-60 keV fluxes were 46+/-2 mCrab on Feb 11 and 79+/-2 mCrab on Feb 14. The 60-150 keV fluxes did not show a significant increase: they were 45+/-7 and 60+/-7 mCrab, respectively, on the above quoted days. Preliminary spectral analysis indicates that in the range 20-150 keV the spectrum of the source has indeed steepened: a power-law with photon index of 2.6+/-0.1 fits the INTEGRAL observations on Feb 14.

The RXTE/PCA Galactic Bulge scans, however, show a decrease of the source at lower energies (2-10 keV), from 840 mCrab on Feb 9 to 710 mCrab on Feb 12 to 670 mCrab on Feb 15 (all +/-4 mCrab). This is in contrast to the spectral behaviour described above.

These findings may indicate a state change, which could be accompanied by changes in the emission at other wavelengths. We again note that an INTEGRAL ToO observation of XTEJ1817-330 is presently ongoing and will last up to Feb 17, 11:20 UTC. Observations at other wavelengths are therefore encouraged.

Original language	English
Publication date	16 Feb 2006
Publication status	Published - 16 Feb 2006

Series	The Astronomer's telegram
Number	ATel #738

Keywords

X.ray
Gamma ray
Binary
Black hole
Transient
Variables

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Kuulkers, E., Goldoni, P., Shaw, S. E., Brandt, S., Chenevez, J., Courvoisier, T. J-L., Ebisawa, K., Kretschmar, P., Markwardt, C., Mowlavi, N., Oosterbroek, T., Orr, A., Paizis, A., Rodriguez, J., Sanchez-Fernandez, C., & Wijnands, R. (2006, Feb 16). INTEGRAL and RXTE monitoring of XTE J1817-330: evolving through a state change? The Astronomer's telegram, No. ATel #738 http://www.astronomerstelegram.org/?read=738

Kuulkers, E. ; Goldoni, P. ; Shaw, S. E. ; Brandt, S. ; Chenevez, J. ; Courvoisier, T. J.-L. ; Ebisawa, K. ; Kretschmar, P. ; Markwardt, C. ; Mowlavi, N. ; Oosterbroek, T. ; Orr, A. ; Paizis, A. ; Rodriguez, J. ; Sanchez-Fernandez, C. ; Wijnands, R. / INTEGRAL and RXTE monitoring of XTE J1817-330: evolving through a state change?. 2006. (The Astronomer's telegram; No. ATel #738).

@misc{627749de8b8e40be86a5c114fe280647,

title = "INTEGRAL and RXTE monitoring of XTE J1817-330: evolving through a state change?",

abstract = " INTEGRAL Galactic Bulge monitoring observations (ATel #438) indicate that the X-ray transient and black-hole candidate XTE J1817-330 (ATel #714) has increased in hard X-rays (20-60 keV) compared to the observations performed on Feb 9, 2006 (ATel #731). The 20-60 keV fluxes were 46+/-2 mCrab on Feb 11 and 79+/-2 mCrab on Feb 14. The 60-150 keV fluxes did not show a significant increase: they were 45+/-7 and 60+/-7 mCrab, respectively, on the above quoted days. Preliminary spectral analysis indicates that in the range 20-150 keV the spectrum of the source has indeed steepened: a power-law with photon index of 2.6+/-0.1 fits the INTEGRAL observations on Feb 14.The RXTE/PCA Galactic Bulge scans, however, show a decrease of the source at lower energies (2-10 keV), from 840 mCrab on Feb 9 to 710 mCrab on Feb 12 to 670 mCrab on Feb 15 (all +/-4 mCrab). This is in contrast to the spectral behaviour described above.These findings may indicate a state change, which could be accompanied by changes in the emission at other wavelengths. We again note that an INTEGRAL ToO observation of XTEJ1817-330 is presently ongoing and will last up to Feb 17, 11:20 UTC. Observations at other wavelengths are therefore encouraged. ",

keywords = "X.ray, Gamma ray, Binary, Black hole, Transient, Variables",

author = "E. Kuulkers and P. Goldoni and Shaw, {S. E.} and S. Brandt and J. Chenevez and Courvoisier, {T. J.-L.} and K. Ebisawa and P. Kretschmar and C. Markwardt and N. Mowlavi and T. Oosterbroek and A. Orr and A. Paizis and J. Rodriguez and C. Sanchez-Fernandez and R. Wijnands",

year = "2006",

month = feb,

day = "16",

language = "English",

series = "The Astronomer's telegram",

publisher = "R. Rutledge",

number = "ATel #738",

type = "Other",

}

INTEGRAL and RXTE monitoring of XTE J1817-330: evolving through a state change? / Kuulkers, E.; Goldoni, P.; Shaw, S. E.; Brandt, S.; Chenevez, J.; Courvoisier, T. J.-L.; Ebisawa, K.; Kretschmar, P.; Markwardt, C.; Mowlavi, N.; Oosterbroek, T.; Orr, A.; Paizis, A.; Rodriguez, J.; Sanchez-Fernandez, C.; Wijnands, R.

2006. (The Astronomer's telegram; No. ATel #738).

Research output: Other contribution › Net publication - Internet publication › Research