TO: All GCN Notice recipients RE: Swift-BAT_Monitor_Alert Notice type is available DT: 23 Feb 2010 INTRODUCTION: The GCN system has been modified to incorporate the distribution of the Swift_BAT_Monitor_Alert notices. This notice type contains information about outbursts (increases in the flux) of any of the 741 hard x-ray sources routinely monitored by Swift-BAT. OCCURANCE RATE: These will occur about 45 times per month. OUTBURST DETECTION ALGORITHM: The detection algorithm for detecting oubursts involves a combination of flux increases above the long-term average, above the recent variance, and above a ratcheting-up threshold to prevent multiple triggers on closely spaced mini-but-related outbursts. FALSE POSITIVES: Given that the outburst threshold is set low and that outburst detection algorithm not sophisticated, there will be false positives in this notice type stream. The false positive rate is ~20%. Given this relatively high false positive rate, the intended recipients of this new notice type are robotic telescopes that (a) have waiting time between bursts, and (b) are not too impacted by taking data on false positives. Of course, anyone (non-robotics) can sign up for this type. Advanced warning about an outburst of their favorite source will allow them to trigger TOOs on other telescopes. TIME DELAY: Given that the data used in the BAT Monitor program comes down the telemetry link with delay 1 to 8 hours, plus an ~2 hr processing time, plus the time it takes for the ground processing to have a significant enough flux increase in the source, the total delay ranges from ~4 hrs to 36 hrs. ERROR: There is no position uncertaintly in this new notice type, because they are known sources (e.g. PKS 1717+177, CygX-1, Mrk 421). ACTION ITEM: If, after reviewing the information below, you want to receive these Swift_BAT_Monitor_Alert notices, please send me a request to have them enabled. You can do this by forwarding this email to scott@milkyway.gsfc.nasa.gov . ARCHIVE STORAGE: The GCN/Swift BAT Monitor Notices are archived within the GCN website in the Table of Swift-BAT Monitor Alerts: http://gcn.gsfc.nasa.gov/gcn/bat_mon_alerts.html MORE INFORMATION: Can be found at: http://gcn.gsfc.nasa.gov/gcn/swift.html The full set of BAT's Hard X-ray Source monitoring can be found at http://swift.gsfc.nasa.gov/docs/swift/results/transients/ APOLOGIES: My apologies to those of you that got about 4 instances of this new notice type. I was doing some final "live" testing last night, and I forgot to turn on the block2world filter for this type. As such, they went out to nearly all the sites. NOTICE EXAMPLE: Here is an example of a full-format email SWIFT_BAT_MONITOR_ALERT Notice: Subject: GCN/TYPE_SWIFT_BAT_MONITOR TITLE: GCN/SWIFT NOTICE NOTICE_DATE: Tue 02 Feb 10 11:33:58 UT NOTICE_TYPE: Swift-BAT Monitor Alert SOURCE_OBJ: 0FGL J1855.9+0126 REF_NUM: 1 RA: 283.985d {+18h 55m 56s} (J2000), 284.113d {+18h 56m 27s} (current), 283.351d {+18h 53m 24s} (1950) DEC: +1.435d {+01d 26' 06"} (J2000), +1.449d {+01d 26' 55"} (current), +1.369d {+01d 22' 09"} (1950) CURR_FLUX: 0.0080 [cnts/cm2/sec] 35.00 [mCrab] BASELINE_FLUX: 0.0000 [cnts/cm2/sec] SIGNIF: 8.24 [sigma] OUTBURST_DATE: 15229 TJD; 33 DOY; 10/02/02 OUTBURST_TIME: 17168.00 SOD {04:46:08.00} UT SAMPLING: Daily SOLN_STATUS: 0x0 FLAGS: 0x40000001 LC_URL: http://swift.gsfc.nasa.gov/docs/swift/results/transients/weak/0FGLJ1855.9p0126 SUN_POSTN: 335.08d {+22h 20m 20s} -10.35d {-10d 21' 00"} SUN_DIST: 52.07 [deg] Sun_angle= 3.4 [hr] (West of Sun) MOON_POSTN: 58.58d {+03h 54m 19s} +24.21d {+24d 12' 54"} MOON_DIST: 128.92 [deg] MOON_ILLUM: 49 [%] GAL_COORDS: 34.72, -0.35 [deg] galactic lon,lat of the known-source transient ECL_COORDS: 285.35, 24.13 [deg] ecliptic lon,lat of the known-source transient COMMENTS: SWIFT-BAT Monitor. COMMENTS: This Notice was ground-processed from flight-data. The socket packets contents can be found at: http://gcn.gsfc.nasa.gov/gcn/sock_pkt_def_doc.html Sincerely, Scott Scott Barthelmy NASA-GSFC, Code 661, Greenbelt, MD 20771 PHONE: 301-286-3106 (office) CELL: 301-346-3733 FAX: 301-286-1684 (1st choice, -1682 2nd choice) EMAIL: scott@lheamail.gsfc.nasa.gov PAGER: 3013463733@cingularme.com WEB: http://gcn.gsfc.nasa.gov/gcn