RXTE Galactic Center Observation

Commentary

Craig Markwardt writes:

Here are the reports of the galactic bulge scans of 25 & 30 Aug 1999
(days 2062 and 2067).  

The processing of day 2062 was delayed as I dealt with a flare as
described below:

 > We detected something peculiar in our most recent scan of the galactic
 > bulge today, 25 Aug 1999 (day 2062).
 > 
 > A fairly bright source appeared near the galactic center (approx
 > coordinates below).  The intensity was about 1500 ct/s/5PCU (2-13keV)
 > = 150 mCrab.  The peculiar thing is that it didn't show up in the
 > neighboring scans, so of course it screwed up the fitting process.  It
 > also means that it was just a short flare of a few hundred seconds or
 > less, perhaps a long-lived burst?  
 > 
 > Jean, if you have simultaneous WFC coverage, it would be interesting
 > to see if you can confirm.  The time was MJD 51415.5897; 25 Aug 1999
 > 14:09 UT.
 > 
 >                  RA         DEC    RATE
 > XTE J1745-302  266.4400  -30.2000  1500    

The flare was seen in only a single scan so I had to rework some of
the pipeline processing to accomodate such a variable source.
[Otherwise, all scans are fitted jointly].  The new best position is

XTE J1745-302  266.4400  -30.0800  2100

The declination is probably good to 0.05 degree.  However, as you may
know the error box for XTE scans is much larger on the axis transverse
to the scan direction.  Therefore, the RA is known to only a degree or
so.  Given those facts, I would argue that this burst is most
consistently explained as coming from either SLX 1744-300 or -299 (I
cannot really distinguish the two with the PCA).

In that case, the measured peak flux, corrected for collimator
response, is about 330 mCrab.  There also seems to be some residual
counts in the persistent source of about 100 mCrab but this would not
be unexpected.

The reconstructed flux of SLX 1744-300/299 appears to have returned to
its persistent level this week.

Another event of note:

 * XTE J1819-254 is currently at a low point of about 2-3 mCrab, the
   lowest in the past six months.


Craig

Known Sources: ASCII table

Scan Light Curve

	Legend -------------------------- 1 - XTE J1710-281 3 - OPH CLU 5 - WGAJ1715.3-2635 8 - XTE J1719-356 9 - XTE J1720-318 10 - RXS J172006.1 11 - XTE J1723-376 12 - EXO 1722-363 13 - RXS J172525.5 14 - XTE J1726-283 15 - TERZAN 2 16 - XTE J1728-295 18 - 4U 1728-34 19 - GX 1+4 20 - RXS J173251.1
	Legend -------------------------- 19 - GX 1+4 24 - XTE J1734-234 25 - KS 1731-260 26 - KS 1732-273 27 - GRS 1734-292 30 - SLX 1735-269 31 - XTE J1739-302 32 - XTE J1739-285 33 - SLX 1737-282 35 - XTE J1743-363 36 - 1E1740.7-2942 37 - XTE J1744-230 38 - KS 1741-293 39 - GCRT J1745-3009 40 - EXO 1742-326 42 - 2S1742-294 43 - GCRT J1746-2757 44 - 1E1743.1-2843 45 - H1743-322 46 - SAXJ1747.0-2853 48 - SLX 1744-300 49 - SLX 1744-300B 50 - XTE J1747-274 51 - GX 3+1 58 - IGR J17497-2821 59 - SLX 1746-331 60 - 2E1746.7-3225 62 - SAXJ1750.8-2900 63 - GRS 1747-312 65 - XTE J1751-305 71 - XTE J1755-312 72 - XTE J1756-342 191 - GX 1+4
	Legend -------------------------- 37 - XTE J1744-230 50 - XTE J1747-274 58 - IGR J17497-2821 62 - SAXJ1750.8-2900 63 - GRS 1747-312 65 - XTE J1751-305 68 - XTE J1752-280 71 - XTE J1755-312 72 - XTE J1756-342 74 - XTE J1757-306 75 - IGR J17586-2129 77 - GX 5-1 78 - GRS 1758-258 81 - RXS J180326.2 83 - XTE J1805-295 84 - XTE J1807-294 86 - 2S1803-245 96 - XTE J1814-338 192 - GX 3+1 193 - GX 5-1
	Legend -------------------------- 85 - SAXJ1806.5-2215 86 - 2S1803-245 87 - RXS J180824.5 90 - SGR 1806-20 92 - XTE J1810-189 93 - SAXJ1810.8-2609 95 - XTE J1812-230 101 - XTE J1819-254 102 - XTE J1819-254P 103 - 4U 1820-30 104 - GS 1826-238 105 - R 1832-330 150 - G11.2-0.3 194 - 4U 1820-30 195 - 4U 1820-30

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