Gamma-Ray Burst Explorer:
Afterglow Follow-up & Swift Constraints
John Nousek (Penn State University)
Swift & GRBs: Unveiling the Relativistic Universe, San Servolo, Venice, 5-9 June 2006
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MOC Facility
Located in State College, PA
~ 4 km. from Penn State campus
Flight Operations Team (FOT)
– responsible for observatory
Health & Safety
Science Operations Team
(SOT)
- responsible for scientific
operation of Swift
Has continuously operated
Swift successfully from L+80
minutes to now!
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Swift Operations Organization
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Mission Ops Center (MOC): Penn State
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BAT Instrument: Goddard Space Flight Center
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GCN immediately distributes Swift messages to subscribers
SDC processes data on receipt, and immediately posts on web
Data Archiving & Science Support Cntr: Goddard Space Flight Center
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Monitors instrument, responds to GRBs, conducts ToO observations
Instrument personnel: PSU, plus Mullard (UK), & GSFC
Pipeline processing: Goddard Space Flight Center
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Monitors instrument, responds to GRBs, conducts ToO observations
Instrument personnel: PSU, plus Italy (Brera, ASDC, Palermo), & U. Leicester
UVOT Instrument: Penn State
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Monitors instrument, responds to GRBs, conducts sky survey
Instrument personnel: GSFC plus Los Alamos
XRT Instrument: Penn State
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Controls observatory, monitors health & safety, generates observing plans
Flight ops: 3 Omitron, 2 PSU engineers
Archiving integrated with HEASARC, using standard tools & access
Ground Network: Goddard Space Flight Center
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Malindi tracking station provided by Italian space agency (USN backup)
TDRSS DAS & WDISC support provided by NASA
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Publications
Publications in first 1.5 years
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~120 papers published in ApJ, A&A, MNRAS
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~60% with first author not on Swift team
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13 Letters in Nature & Science
(http://swift.gsfc.nasa.gov/docs/swift/results/publist
for list of papers and links)
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~600 Swift GCN Circulars
(plus ~800 community GCNs for Swift GRBs)
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~50 ATELs and IAU Circulars
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4 press events
Popular Science
"Best of What's New
in Space Science"
Statistics courtesy of Neil Gehrels – Apr, 2006
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Swift Observatory Status
Swift meets or exceeds all Level 1 requirements !
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Observatory Science Up-time: 96.7%
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Ground Station Status: Nominal
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Orbital life expected to >2013, no observatory or instrument limits known
Flight Operations Team Response: Excellent
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ACS: executed 41,453 slews, >99% within 3’ accuracy
All systems functioning properly, without any signs of degradation
Observatory Lifetime: Above prediction
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Malindi 5607 passes since Launch, 99.3% successful
TDRSS DAS currently providing 99.3% success rate
USN backup provided 3 successful of 3 requested passes since Apr, 2005
Observatory Status: Nominal
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Except for rare spacecraft or instrument down-time and SAA passage, Swift
collects data continuously
On average, there was an FOT after hours response once every three days
Science Operations Team Response: Excellent
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SOT has prepared schedules for Swift every day without an SOT induced error
SOT/BA team has responded to every GRB with prompt (typical < 1 hour) data
analysis and preparation of GCN circulars, ATELs etc for about 200 events
Statistics from Rob Laverghetta, FOT as of 21 May 2006
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Swift Observatory Status - 2
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BAT Status: Nominal
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XRT Status: Nominal
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UVOT achieves proposed limiting sensitivity
All components functioning properly, without any signs of degradation
Flight Software Status: Nominal
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XRT detects ~97% of afterglows with prompt response
TEC failure has been controlled by operations plan
Micro-meteoroid impact has been limited to just 3 columns (of 600)
UVOT Status: Nominal
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All 16 detector modules functioning properly
GRB discovery rate consistent with pre-launch predictions
BAT in GRB detection mode for ~98% of total available time
All three instruments have successfully upgraded on-board software &
parameters
Upgrades have enhanced operational efficiency & science return
Data Capture: Nominal
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99.99% of Engineering and Science Data captured on ground
Statistics from Rob Laverghetta, FOT as of 21 May 2006
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Orbital Lifetime
Alan Wells
Improved orbital
prediction suggests
extended mission life.
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Swift Mission Life
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Observatory Status: No known limits
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Design life is 5 years
No sign of degradation in any system at this time
No consumables
Instrument Status: No known limits
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XRT micro-meteroid impact rate uncertain
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Wells et al. conducted study which estimated rate of 0.1-0.2 hits per year
UVOT filter wheel is moving part; redundant assembly available
Mission Life Projection: Exceeds launch prediction
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No obvious life limitations
Probability is high that Swift will exceed 5 year lifetime goal
Report from Alan Wells
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Swift Observing Statistics
•
Swift observing time divided its time as follows:
All GRB obs:
56.3%
New triggers
8.4%
Planned follow-up
42.6%
GRB ToOs
5.5%
Non-GRB ToO*s:
8.8%
Calibration:
5.1%
Planned non-GRB targets:
SAA & non-science:
17.6% (5 Msec/yr)
12%
Cycle 3 will open ToO's to GI proposal
Cycle 4 will open planned non-GRB targets to GI proposal
* 153 ToO's requested/ 103 approved. Examples: Comet Tempel, RS Oph, supernovae
Statistics through May 16 – courtesy of Kim Page
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Swift Observing Strategy
SOT prioritizes targets by following criteria:
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GRB automated response, afterglow followup, GRB ToO: 64%
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Targets of Opportunity (non-GRB ToO): 10%
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Currently solicited via public webpage with 5 levels of urgency
Approved by Neil Gehrels, Swift PI
Swift AO-3 will allow peer review of ToO proposals
Instrument Calibration: 6%
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Visible GRB afterglows receive top priority
Typically 2-6 afterglows visible each day, but require ~4 targets per orbit
Proposed by instrument teams as needed
Fill-in Targets: 18%
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Selected from lists proposed by Swift team which survived internal peer review
Only observed when no targets in higher priority levels are available
Chosen with consideration to maximize sun angle and reduce XRT temperature
Swift AO-4 will allow peer review of target proposals from general community
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Fill-in Target Progress
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Swift team provided targets in two rounds
New round to be solicited by Neil Gehrels
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With Swift AO-4 non-team proposers will be able to request targets
Subject to peer review, US proposers eligible to receive NASA funding
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Individual targets not guaranteed
Equivalent to ROSAT, ASCA, etc, Type C time
Round 1
Finished (>90%)
Round 2
Total
201
136
337
Incomplete
45
63
108
Unobserved
21
111
132
267
310
577
Total time
3.97 Msec
1.30 Msec
5.28 Msec
Requested time
2.39 Msec
1.96 Msec
4.35 Msec
77.8%
41.9%
61.6%
Total
Target Completion (%)
Report from Jamie Kennea – 31 May 2006
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Example of “Hot/Cold” Skymap
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Fill-in target completion from Round 1
Round 1 Completion
90
70
50
Dec (degrees)
30
10
Complete
Incomplete
Unobserved
-10
-30
-50
-70
-90
0
50
100
150
200
250
300
350
Ra (degrees)
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Fill-in target completion from Round 2
Round 2 Completion
90
70
50
Dec (degrees)
30
10
Completed
Incomplete
Unobserved
-10
-30
-50
-70
-90
0
50
100
150
200
250
300
350
RA (degrees)
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Swift Institutions
GSFC
Executive Committee
G. Chincarini - Brera Obs.
N. Gehrels - GSFC
P. Giommi - ASI
K. Mason - MSSL
J. Nousek - PSU
J. Osborne - U. Leicester
A. Wells - U. Leicester
N. White - GSFC16
Swift Observing Constraints
Swift has the following visibility constraints:
Constraint
EarthLimb
Moon
Sun
Ram
Spacecraft
28°
21°
45°
5°
CHILE TAKO
28°
33°
21°
23°
45°
46°
10°
BAT
23°
45°
UVOT
26°
19°
44°
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Backup Slide – MAL Stats
Reporting
Total Successful Unsuccessful
DOY Span
Period
Passes
Passes
Passes
Nov-04
325-335
113
112
1
Dec-04
336-366
317
314
3
Jan-05
001-031
323
319
4
Feb-05
032-059
308
307
1
Mar-05
060-090
345
344
1
Apr-05
091-120
335
335
0
May-05
121-151
345
343
2
Jun-05
152-181
334
328
6
Jul-05
182-212
344
343
1
Aug-05
213-243
346
340
6
Sep-05
244-273
332
325
7
Oct-05
274-304
344
343
1
Nov-05
305-334
337
333
4
Dec-05
335-365
345
344
1
Jan-06
001-031
344
343
1
Feb-06
032-059
200
198
2
Mar-06
060-090
301
300
1
Apr-06
091-120
294
294
0
May-06
121-141
208
206
2
Grand Totals
5607
5565
44
Malindi Success Percentage since Launch:
99.25%
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Backup Slide – Sci Uptime
Hours Mins
Apr-05
May-05
Jun-05
Jul-05
Aug-05
Sep-05
Oct-05
Nov-05
Dec-05
Jan-06
Feb-06
Mar-06
Apr-06
May-06
0
13
86
37
0
0
1
29
0
9
104
1
22
4
0
26
87
60
0
55
50
20
0
49
126
33
70
7
Total Mins Cum mins Days per Mins per Cum mins
Down
Down
month
month
month
0
806
5247
2280
0
55
110
1760
0
589
6366
93
1390
247
0
806
6053
8333
8333
8388
8498
10258
10258
10847
17213
17306
18696
18943
30
31
30
31
31
30
31
30
31
31
28
31
30
31
43200
44640
43200
44640
44640
43200
44640
43200
44640
44640
40320
44640
43200
44640
43200
87840
131040
175680
220320
263520
308160
351360
396000
440640
480960
525600
568800
613440
Monthly %
100.0%
98.2%
87.9%
94.9%
100.0%
99.9%
99.8%
95.9%
100.0%
98.7%
84.2%
99.8%
96.8%
99.4%
Since
Apr 05%
100.0%
99.1%
95.4%
95.3%
96.2%
96.8%
97.2%
97.1%
97.4%
97.5%
96.4%
96.7%
96.7%
96.9%
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