TY - ICOMM
T1 - Two active X-ray transients in the Galactic Center region as seen by INTEGRAL
AU - Kuulkers, E.
AU - Shaw, S.
AU - Chenevez, J.
AU - Brandt, S.
AU - Courvoisier, T.
AU - Domingo, A.
AU - Kretschmar, P.
AU - Markwardt, C.
AU - Mowlavi, N.
AU - Paizis, A.
AU - Risquez, D.
AU - Sanchez-Fernandez, C.
AU - Winjnands, R.
PY - 2007/2/16
Y1 - 2007/2/16
N2 -
The first of a new series of INTEGRAL Galactic bulge monitoring observations
(ATel #438, #874) performed between UT 2007, Feb 15 18:35 and 22:17 shows
two transient X-ray sources to be active in the Galactic Center region.
One is the recently found source IGR J17453-2853 at RA, Dec (Degrees) = 266.32, -28.89,
with a 90% confidence error region of 2 arcmin (Kuulkers et al. 2007, A&A, in press,
astro-ph/0701244). The IBIS/ISGRI 20-60 keV flux was about 11 mCrab,
with a detection significance of 8. It is not detected in the JEM-X 3-10
and 10-25 keV bands with upper limits of about 5 mCrab in both bands. This source was
last seen to be active at similar flux levels between 2005, April 3 and 14. As
noted by Kuulkers et al. (2007), if the non-detection with JEM-X is due to absorption in
the line of sight, N_H should be larger than about 10^23 atoms per cm^2.
The other source is detected with JEM-X at RA, Dec (Degrees) = 266.40, -29.05, with
a 90% confidence error region of 2 arcmin. There are various known X-ray transients
within the error circle, such as Swift J174535.5-290135.6 (e.g., ATel #753, #756) or
CXOGC J174535.5-290124 (e.g., ATel #753, #892). It is detected at about 22 mCrab in 3-10
keV, with a detection significance of 14. The source is clearly variable on a 15-minute time
scale. It is not detected in the JEM-X 10-25 keV band with an upper limit of about 5 mCrab.
Follow-up observations with more position sensitive instruments are needed to pin-point
the exact origin of the transient X-ray emission.
AB -
The first of a new series of INTEGRAL Galactic bulge monitoring observations
(ATel #438, #874) performed between UT 2007, Feb 15 18:35 and 22:17 shows
two transient X-ray sources to be active in the Galactic Center region.
One is the recently found source IGR J17453-2853 at RA, Dec (Degrees) = 266.32, -28.89,
with a 90% confidence error region of 2 arcmin (Kuulkers et al. 2007, A&A, in press,
astro-ph/0701244). The IBIS/ISGRI 20-60 keV flux was about 11 mCrab,
with a detection significance of 8. It is not detected in the JEM-X 3-10
and 10-25 keV bands with upper limits of about 5 mCrab in both bands. This source was
last seen to be active at similar flux levels between 2005, April 3 and 14. As
noted by Kuulkers et al. (2007), if the non-detection with JEM-X is due to absorption in
the line of sight, N_H should be larger than about 10^23 atoms per cm^2.
The other source is detected with JEM-X at RA, Dec (Degrees) = 266.40, -29.05, with
a 90% confidence error region of 2 arcmin. There are various known X-ray transients
within the error circle, such as Swift J174535.5-290135.6 (e.g., ATel #753, #756) or
CXOGC J174535.5-290124 (e.g., ATel #753, #892). It is detected at about 22 mCrab in 3-10
keV, with a detection significance of 14. The source is clearly variable on a 15-minute time
scale. It is not detected in the JEM-X 10-25 keV band with an upper limit of about 5 mCrab.
Follow-up observations with more position sensitive instruments are needed to pin-point
the exact origin of the transient X-ray emission.
KW - X-ray
KW - Binary
KW - Black hole
KW - Neutron star
KW - Transient
KW - Variables
M3 - Net publication - Internet publication
T3 - The Astronomer's telegram
ER -