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Chandra Localization of IGR J17451-3022

ATel #6533; Deepto Chakrabarty (MIT), Peter G. Jonker (SRON), Craig B. Markwardt (NASA/GSFC)
on 3 Oct 2014; 19:07 UT
Credential Certification: Deepto Chakrabarty (deepto@space.mit.edu)

Subjects: X-ray, Binary, Black Hole, Neutron Star, Soft Gamma-ray Repeater, Transient

As part of an ongoing program for precise localization of X-ray transients, we obtained a short Chandra observation of the transient IGR J17451-3022 (ATEL #6451, #6459, #6469, #6486, #6501). Our observation was made on 2014 September 29 05:12 TT with an exposure time of 1155 s, using the HRC-S instrument in timing mode. The source was detected with a mean count rate of 1.11(3) count/s. The best-fit X-ray source position is:

RA(J2000) = 17h 45m 06.72s
Dec(J2000) = -30d 22' 43.3"

with an uncertainty radius of 0.6 arcsec (90 percent confidence). This is consistent with the 2.1 arcsec (90 percent confidence) Swift/XRT error circle measured on September 5 (ATEL #6451), lying 0.8 arcsec from its center.

No pulsations or significant variability were detected. The upper limit on the fractional rms pulsation amplitude is 17 percent (95 percent confidence). Our HRC-S observation does not provide useful spectral information. However, assuming the absorbed blackbody spectrum measured by Swift on September 25 (ATEL #6501; kT=1.0 keV, N_H=6e22 cm^(-2)), our measured count rate corresponds to an absorbed flux of 1.7e-10 erg/cm^2/s (0.2-10 keV).

The nature of this transient remains unclear.