21 December, 1999 --

• XTE J1859+226 - ~130 mCrab on the basis of relatively few but mutually consistent observations
• GRS 1915+105 - ~500 mCrab and relatively steady as seen in ~5 observations spread out through the week
• 3A 1942+274 - a few observations indicate that the intensity is down to 10+-7 mCrab
• SAX J21035+4545 - appears to be ~13 mCrab

14 December, 1999 --

• 1ES0821-426 - This source may be at a strength of ~10 mCrab.
• XTE J1859+226 - around 130 mCrab on the basis of relatively few observations
• Cyg X-3 - appears to be relatively weak, ~60 mCrab, on the basis of few observations

7 December, 1999 --

• RX J08124-312 - very weak, < 7 mCrab
• XTE J1859+226 - stable around 170 mCrab

The right ascension of the sun is now approaching 17 h, so that there have been few measurements from the Galactic Center region this week. This will of course continue to be a problem for a number of weeks.

30 November, 1999 --

• RX J08124-312 - ~13 mCrab
• XTE J1859+226 - decreased to ~200 mCrab
• SAX J21035+4545 - below 10 mCrab
• SS Cygni - about 10 to 15 mCrab

26 November, 1999 --

• RXJ08124-312 - There is an indication that this is above 15 mCrab.
• XTE J1859+226 - down to ~270 mCrab
• 3A 1942+274 - stable around 25 mCrab
• Cyg X-3 - daily averages are around 120 mCrab, i.e., more or less quiescent
• SAX J21035+4545 - around 10 mCrab

16 November, 1999 --

• X 1702-429 - was as strong as 130 mCrab
• 4U 1705-44 - down to ~15 mCrab
• XTE J1739-285 - remained around roughly 100 mCrab
• XTE J1859+226 - down to ~400 mCrab
• 3A 1942+274 - up to ~25 mCrab
• X 1957+115 - ~60 mCrab
• SAX J21035+4545 - still 15 mCrab or more

8 November, 1999 --

• 4U 1705-44 - Down to ~25 mCrab
• XTE J1859+226 - decreased to just above 0.5 Crab
• 3A 1942+274 - increased to ~25 mCrab
• X 1957+115 - increased to ~50 mCrab
• SAX J21035+4545 - stable at ~25 mCrab

2 November, 1999 --

• 4U 1705-44 - down to ~50 mCrab
• X 1730-333 (Rapid Burster) - down to ~15 mCrab or less
• XTE J1859+226 - varied within the range 0.55 to 1.0 Crab
• SS 433 - continues at about 15 mCrab
• GRS 1915+105 - highly variable within the range 0.33 to 2.7 Crab
• SAX J21035+4545 - the data suggests a rise in intensity to above 15 mCrab

27 October, 1999 --

• X1658-298 - up to ~45 mCrab
• 4U 1705-44 - down to ~100 mCrab
• X1730-333 (Rapid Burster) - down to ~40 mCrab
• XTE J1859+226 - down to ~0.6 Crab at the end of the week
• GRS 1915+105 - 1 to 2.6 Crabs
• Cyg X-3 - strength and activity are diminishing gradually (daily averages ~120 mCrab)

18 October, 1999 --

• Cen X-3 - intensity has decreased substantially and was below ~25 mCrab at the end of the week
• XTE J1859+226 - this new transient rose to ~530 mCrab at week's end (and above 1 Crab during week 194)
• Aql X-1 - was wandering in the vicinity of 50 to 70 mCrab
• GRS 1915+105 - strong and active (up to 2.4 Crab)
• Cyg X-1 - varying with a typical strength of ~0.4 Crab
• X 1957+11 - up to ~40 mCrab
• Cyg X-3 - active, but with indications of short quiescent interludes
• SS Cyg - shows wavelike variability with peak strength of nearly 25mCrab

14 October, 1999 --

• X 1730-333 (Rapid Burster) - down to ~130 mCrab at week's end
• KS 1731-260 - down to 20 mCrab or less
• Aql X-1 - around 40 mCrab
• GRS 1915+105 - declined to 1.2 Crab and then flared to ~2 Crab
• Cyg X-1 - still flaring with strength up to just over 1 Crab, but generally not as strong as the previous week
• X 1957+115 - up to ~40 mCrab

Note for week 193: A new source, XTE J1859+22, was found. See the IAU Circulars for details.

5 October, 1999 --

• X1658-298 - up to ~25 mCrab
• X1730-333 (Rapid Burster) - began another outburst & was up to ~250 mCrab
• AX J1820.5-1434 - may be getting stronger (possibly is in 25 - 50 mCrab range)
• 3A 1942+274 - down to < 10 mCrab
• Cyg X-1 - active in range 0.5 to 1.3 Crab

28 September, 1999 --

• Cen X-3 - was in a high state with strength up to ~330 mCrab
• 3A 1942+274 - down to ~15 mCrab

Not much other excitement

21 September, 1999 --

• Cen X-3 - has returned to a reasonably bright level, ~250 mCrab, in sporadic measurements over this week
• GM Sgr = SAX J1819.3-2525 = XTE J1819-254 - We detected a very strong flare, which had a maximum observed strength of ~12 Crabs, this week (announced in an IAU Circular). Very little flux has been seen since the strong flare.
• Aql X-1 - is at ~40 mCrabs and we may be seeing occasional X-ray bursts

14 September, 1999 --

• 4U 1705-44 - down to ~290 mCrab
• KS 1731-260 - around 130 mCrab
• GRS 1915+105 - steadier and near 1.3 Crabs

7 September, 1999 --

• LMC X-3 - strength has decreased to ~20 mCrab
• IC 4329A - This week's results do not indicate much strength.
• 4U 1705-44 - up to ~390 mCrab
• GRS 1915+105 - active within the range 0.8 to 1.2 Crab

1 September, 1999 --

• x1323-619 (an LMXB) - may be stronger than seen by ASM earlier in the RXTE mission, at ~20 mCrab
• IC 4329A - light curve indicates strength of ~15 mCrab; it is unclear if this is real or an artifact, but there is no particular evidence that it is an artifact
• 4U1705-44 - declined slightly to ~290 mCrab
• 3A 1942+274 - up to ~25 mCrab
• Cyg X-3 - still strong and active, daily averages ~260 mCrab

24 August, 1999 --

• x1608-522 burbling increasing to 80 mCrab
• x1705-440 continues rising to 330 mCrab
• KS 1731-260 still faint (near 25 mCrab)
• GX 354-0 bright at 180 mCrab
• GRS 1915+105 more steady, at 1.0 Crab
• x1953+319 still at 25 mCrab
• Cyg X-3 still bright, 250-300 mCrab

17 August, 1999 --

• x1630-472 outburst finished - now below ASM detection
• x1702-429 post maximum, down to 40 mCrab
• x1705-440 increasing to 240 mCrab
• KS 1731-260 faint, down to 13 mCrab
• Aql X-1 continues fading; 10-20 mCrab
• GRS 1915+105 avg is 0.9 Crab ; stuck in mode of very deep, 30-sec oscillations
• x1953+319 flares to 60 mCrab
• Cyg X-3 bright, daily averages at 250-300 mCrab

10 August, 1999 --

• Cir X-1 - a lot of activity and high intensity points around phase zero
• 4U 1630-47 - ~15 mCrab
• Her X-1 - no sign of a typical high state which should be starting around the end of the week; keep posted for next week's results to confirm if the extended low state is continuing
• X 1702-429 - increased to near its typical highest strength at ~70 mCrab
• 4U 1705-44 - intensity rose rapidly to ~150 mCrab
• GRS 1915+105 - roughly 0.8 Crab
• Cyg X-3 - active ~130 to 400 mCrab

4 August, 1999 --

• Cen X-3 - is in a low state again; < 25 mCrab
• 4U 1630-47 - down to ~25 mCrab
• XTE J1946+274 - down to around 13 mCrab
• X 1953+319 - up to ~25 mCrab

26 July, 1999 --

• X 0114+650 - is above 15 mCrab for the first extended time in the RXTE era
• 4U 0115+634 - showed a temporary excursion to ~20 mCrab
• 4U 1630-47 - decreased to ~50 mCrab
• KS 1731-260 - back up to ~130 mCrab
• NGC 6441 globular cluster source - up to ~50 mCrab
• Aql X-1 - still is burbling around 25 mCrab
• Cyg X-3 - activity is decreasing somewhat

19 July, 1999 --

• 4U 1630-47 - declined to ~50 mCrab
• Her X-1 - still no sign of any high states recently
• Aql X-1 - continues with low level activity (20 - 40 mCrab)
• Cyg X-1 - flared to ~0.8 Crab early in the week
• Cyg X-3 - activity declined from ~250 to ~150 mCrab

• 4U 1630-47 - perhaps declined slightly this week, but still near 160 mCrab
• X 1658-298 - seems to have declined around MJD 51350 from an earlier level of ~25 mCrab to a level below 10 mCrab
• X 1812-121 - may be resuming burst activity (two high intensities were recorded near the end of the week)
• Aql X-1 - ~40 mCrab (not completely quiescent)

7 July, 1999 --

• XTE J0111.2-7317 - there is marginal evidence for a ~12 mCrab intensity
• X 1246-588 - looks possible (but not with 100% confidence) that this source is up to ~20 mCrab
• Cir X-1 - shows an extended interval with relatively low intensity after radio phase zero
• 4U 1630-47 - remains up near ~180 mCrab
• 4U 1705-44 - must be near a minimum in its intensity, at ~40 mCrab or less

30 June, 1999 --

Note: There are a lot of high intensity points in the results from this week, many of which are spurious results. The high frequency of these results is presumably due to the fairly high solar activity level, i.e., an elevated and variable solar X-ray flux.

• Cen X-3 - definitely has gone from a low to high 2-10 keV state, with intensities often as high as ~250 mCrab
• 4U 1630-47 - close to or a bit higher than last week at ~175 mCrab
• 4U 1705-44 - is down near ~30 mCrab
• KS 1731-260 - flux is at low levels of 25 to 40 mCrab
• XTE J1946+274 - possibly climbing to > 25 mCrab
• Cyg X-3 - is relatively active with an average flux near ~200 mCrab

22 June, 1999 --

• LMC X-3 - was very bright at ~45 mCrab
• Cen X-3 - has become bright again after being in a low state for more than 80 days
• Cir X-1 - showed a particularly extended interval of absorption dips around the last time of radio phase zero
• x1608-522 - consistently around 50 mCrab
• 4U 1630-47 - up to ~170 mCrab
• KS 1731-260 - down to ~50 mCrab
• axj1820.5-1434 - results are suggestive of activity in this light curve
• Aql X-1 - down to <15 mCrab
• GRS 1915+105 - still active in the range 0.4 to 2.5 Crab
• Cyg X-1 - up to 0.8 Crab in individual 90 s dwell observations at the very end of the week
• Cyg X-3 - active with up to 0.4 Crab in 90 s observations

14 June, 1999 --

• 4U 1630-47 - up to ~150 mCrab
• CTB 33 - The action noted in last week's report was an artifact based on a catalog management problem and the proximity of 4U 1630-47. No significant activity can be seen in the revised light curve.
• GX 339-4 - very weak, < 10 mCrab
• Aql X-1 - down to ~15 mCrab at week's end
• GRS 1915+105 - highly active, 0.5 - 2.3 Crab
• XTE J1946+274 - intensity is climbing slowly, and is now up to ~23 mCrab

7 June, 1999 --

• 4U 1630-47 - remains at ~130 mCrab
• CTB 33 - there is something going on in the vicinity of this source (RA = 248.7783, Dec = -47.7903)
• Her X-1 - no sign of an upcoming high state expected to have a center near MJD 51332
• Aql X-1 - declining rapidly and down to ~100 mCrab at the end of the week XTE J1946+274 - ~20 mCrab
• Cyg X-3 - more active, up to ~250 mCrab in individual 90 s observations

1 June, 1999 --

• LMC X-3 - relatively strong at ~45 mCrab
• 4U 1630-47 - remains at ~100 mCrab
• GS 1843+009 - appears to be at ~20 mCrab
• Aql X-1 - in a plateau at ~330 mCrab
• GRS 1915+105 - weaker and less active, now at ~500 mCrab
• BL 2005-489 - for the last few weeks, consistently appears to be ~15 mCrab

25 May, 1999 --

• 4U 1630-47 - ~120 mCrab
• 4U 1705-44 - down to ~100 mCrab
• KS 1731-260 - back up to ~130 mCrab
• Aql X-1 - up to ~200 mCrab and rising rapidly
• GRS 1915+105 - highly variable in the range 0.25 Crab to nearly 3 Crab

18 May, 1999 --

• X 0614+091 - declined to < 10 mCrab, an unusually low level
• XTE J1550-564 - declined to below the ASM's detection threshold, i.e., < 10 mCrab
• 4U 1630-47 - another outburst has begun, the intensity rose to ~120 mCrab
• Aql X-1 - an X-ray outburst is just beginning with one day at ~40 mCrab, following the increase in optical brightness
• GRS 1915+105 - intensities varying all over the range 0.25 to 2.4 Crab

12 May, 1999 --

• XTE J1550-564 - mostly < 10 mCrab at the end of the week, with some higher intensities w/ low significance also present
• Her X-1 - no sign (< 10 mCrab) of the second half of the main high state which would usually be seen this week
• XTE J1946+274 - ~15 mCrab and relatively steady

04 May, 1999 --

• XTE J1550-564 - down to ~20 mCrab at the end of the week
• Her X-1 - There is no sign of the main high state which is expected to around MJD 51295.
• 4U 1705-44 - declined to ~200 mCrab
• x1711-339 - < 15 mCrab
• XTE J1723-376 - <10 mCrab
• KS 1731-260 - continues to wander in intensity; is now down to ~40 mCrab
• GRS 1915+105 - as high as 1.5 Crab and shows a generally increasing trend
• XTE J1946+274 - steady at ~20 mCrab

26 April, 1999 --

• 4U 0115+63 - < 10 mCrab
• LMC X-3 - back up to ~25 mCrab
• XTE J1550-564 - down to ~70 mCrab
• 4U 1705-44 - up to ~260 mCrab
• x1711-339 - down to ~10 mCrab
• XTE J1723-376 - decreased to <15 mCrab
• GRS 1915+105 - up to ~1.4 Crab
• XTE J1946+274 - down to ~20 mCrab

22 April, 1999 --

• 4U 0115+63 - down to ~30 mCrab at the end of the week
• LMC X-3 - is getting stronger, i.e, is up to 20 - 30 mCrab
• XTE J1550-564 - ~100 mCrab at week's end
• x1658-298 - ~30 mCrab
• 4U 1705-44 - ~250 mCrab
• XTE J1723-376 - ~25 mCrab
• GRS 1915+105 - a highly active interval was followed by a less active interval, and the intensity was as high as 1.3 Crab
• XTE J1946+274 - down to ~25 mCrab

16 April, 1999 --

• 4U 0115+63 - down to ~60 mCrab at the end of the week
• XTE J1550-564 - down to ~250 mCrab
• x1658-298 - ~40 mCrab
• XTE J1723-376 - remains near 50 mCrab
• X1730-333 (Rapid Burster) - < 15 mCrab
• GRS 1915+105 - up to ~0.9 Crab in daily averages
• XTE J1946+274 - ~40 mCrab
• Cyg X-3 - as high as 190 mCrab in daily averages; this is higher than in the last 100 days

4 April, 1999 --

• 4U0115+63 - down to ~130 mCrab
• Cen X-3 - is in a very low state, < 20 mCrab
• XTE J1550-564 - down to ~470 mCrab
• 4U 1705-44 - up to ~130 mCrab
• x1730-333 (Rapid Burster) - down to ~40 mCrab
• XTE J1946+274 - still around 45 mCrab

30 March, 1999 --

• 4U 0115+63 - down to ~200 mCrab
• Cen X-3 - appears to be entering another extended low state (<25 mCrab)
• XTE J1550-564 - down to ~700 mCrab
• Her X-1 - the high state that should have appeared around MJD 51260 did not materialize - this is very unusual
• X1730-333 (Rapid Burster) - down to ~50 mCrab
• GRS 1915+105 - mostly ~850 mCrab with some obvious variability
• XTE J1946+274 - ~40 mCrab
• Cyg X-1 - a short flare reached ~1 Crab, otherwise the intensity was ~270 mCrab

23 March, 1999 --

• 4U 0115+63 - declined from 330 to 270 mCrab
• XTE J1550-564 - down to ~1.2 Crab
• 4U 1705-44 - up to ~100 mCrab
• X1730-333 (Rapid Burster) - went into outburst with a peak intensity of ~370 mCrab
• GRS 1915+105 - ~700 mCrab
• XTE J1946+274 - rising again and up to ~40 mCrab

Note: Cyg X-1 showed some sharp flaring in week 164.

15 March, 1999 --

• 4U 0115+63 - rather strong and varying up and down around 300 mCrab
• Cen X-3 - is back to a more or less low intensity state
• XTE J1550-564 - fairly steady at ~2.1 Crab
• 4U 1705-44 - rising again and is up to ~100 mCrab
• XTE J1723-376 - roughly 70 mCrab
• GRS 1915+105 - ~670 mCrab with dips down to ~350 mCrab

Note: The Rapid Burster (X 1730-333) turned on at the beginning of week 163.

9 March, 1999 --

• 4U 0115+63 - rose to an apparent peak of ~190 mCrab
• Cen X-3 - may be headed back to a persistently low state
• XTE J1550-564 - roughly steady at ~2.1 Crab
• Mkn 501 - consistently ~13 mCrab
• XTE J1723-376 - ~50 mCrab
• KS 1731-260 - back up to ~130 mCrab
• GRS 1915+105 - varied in the range 270 to 670 mCrab

23 February, 1999 --

• x0115+63 - up to ~65 mCrab at week's end
• XTE J1550-564 - took a small step up to ~2.4 Crab
• x1702-429 - down to ~30 mCrab
• 4U 1705-44 - ~20 mCrab
• XTE J1723-376 - ~60 mCrab
• KS 1731-260 - up to ~110 mCrab
• GRS 1915+105 - ~670 mCrab

23 February, 1999 --

• XTE J0111.2-7317 - < 6 mCrab
• XTE J1550-564 - down to ~2.3 Crab
• X1657-415 - up to ~50 mCrab with strong orbital modulation
• GX 339-4 - steady at ~35 mCrab
• x1702-429 - up to ~110 mCrab
• 4U 1705-44 - down to ~15 mCrab
• XTE J1723-376 - ~60 mCrab (This is a source that was recently discovered in PCA slew data.)

18 February, 1999 --

• SMC X-1 - the long term cycle duration appears to be increasing from < 50 d to > 50 d
• Cir X-1 - the phases in the 16.6 d cycle of the flares and dips has been somewhat changed for the last few cycles
• XTE J1550-564 - down slightly to ~2.5 Crab
• GX 339-4 - ~30 mCrab
• X1702-429 - up to ~70 mCrab
• 4U 1705-44 - down to ~70 mCrab
• GRS 1915+105 - ~0.5 Crab
• XTE J1946+274 - <10 mCrab

10 February, 1999 --

• x1543-624 - up to ~45 mCrab
• XTE J1550-564 - remains at ~2.7 Crab
• GX 339-4 - down to ~40 mCrab
• GRS 1915+105 - ~700 mCrab
• XTE J1946+274 - down to ~10 mCrab

2 February, 1999 --

• XTE J0111.2-7317 - < 10 mCrab
• XTE J1550-564 - ~2.6 Crab
• GRS 1915+105 - up to ~0.7 Crab
• XTE J1946+274 - ~25 mCrab

27 January, 1999 --

• XTE J0111.2-7317 - < 10 mCrab
• EXO 0748-676 - ~15 mCrab
• XTE J1550-564 - remains near ~2.4 Crab
• GX 339-4 - in the 20 - 90 mCrab range and possibly rather variable
• XTE J1946+274 - remains ~40 mCrab
• SS Cygni - relatively strong at ~15 mCrab

20 January, 1999 --

• XTE J0111.2-7317 - appears to have weakened and is now ~13 mCrab
• Cen X-3 - consistently strong at ~300 mCrab
• XTE J1550-564 - remains at ~2.4 Crab
• GX 339-4 - ~80 mCrab - the source is mostly out of the high state
• KS 1731-260 - ~140 mCrab
• GRS 1915+105 - ~0.5 down to ~0.3 Crab
• XTE J1946+274 - back up to ~45 mCrab

13 January, 1999 --

• XTE J0111.2-7317 - few measurements made but flux could be declining
• Cen X-3 - 130 to 250 mCrab outside of eclipse
• XTE J1550-564 - steady at ~2.4 Crab
• GX 339-4 - much lower at ~80 mCrab

7 January, 1999 --

• X 0614+091 - continues with its wavy light curve with extremes of 25 and 100 mCrab
• XTE J1550-564 - up to ~2.2 Crab
• GX 339-4 - very few measurements are available, but it appears that the intensity continues to diminish, and is probably 80 to 160 mCrab
• 4U 1705-44 - back up at ~260 mCrab

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