Burst Detection Checklist for GPS 867120400 event
The LSC-VIRGO Burst Working Group
February 18, 2009

The most recent version of this page in CVS

Top level event information available at http://virgo.physics.carleton.edu/Virgo/VSR1/VSR1S5/triple_boxes.html

Please notice that some of the suggested checks may conflict
with the notion of keeping ourselves blind from the possible
blind injection. Do not undertake any such checks until after
the blind injection challenge has been declared over.

Status: X (Complete), I (Incomplete), O (Open, Critical)

ID Category Check description Status Time Contributors Link Diag Date Signed
1
Zero-level sanity
Convert GPS times to calendar times and check for suspiciousness.
Jun 29 2007 02:46:26 UTC
Mab
Feb 19, 2009
2
Zero-level sanity
Read e-logs for the times/days in question.
Was there anything anomalous going on?
Virgo:2 unlocks reported during the shift due to the input Mode Cleaner "fast unlocks".
First unlock at 01:41 UTC. Second unlock at 02:58 UTC (12 mns after the event).
Horizon ~ 3.4 Mpc during the period. Problem of temperature in the laser lab the day before.
Mab
Virgo Shift Report - 23:00-07:00
Feb 19, 2009
3
Zero-level sanity
Check state vector of all instruments around the time of the candidate.
Data correctly flagged?
Virgo: no archived plot found. From the shift report, Virgo was locked until 12 mns
after the event.
Mab
Feb 19, 2009
4
Zero-level sanity
Identify inspiral range of the instruments in order to set
the scale of sensitivity. Is this typical/low/high?
Virgo: horizon was stable : ~3.4 Mpc. 2 horizon drops (at 3.2 Mpc) reported during the night.
Mab
Feb 19, 2009
5
Zero-level sanity
Identify nearest in time hardware injections (also
type/amplitude of them). Were there ongoing stochastic/pulsar
ones? When did they start and what was their amplitude?
Virgo: no hardware injections done before August.
Mab
Feb 19, 2009
6
Zero-level sanity
How close to segment start/end for all instruments does this event occur?
Virgo segment: 867118071 867121140 3069. Event 1140 sec before an unlock.
Mab
Feb 19, 2009
7
Data integrity
Check for undocumented/unauthorized/spontaneous hardware injections.
8
Data integrity
Examine all possible test points recorded in frames or saved on disk.
The latter part might be time critical if data are overwritten.
9
Data integrity
Establish if there was any data tampering.
10
Data integrity
Check integrity of frames; check raw/RDS/DMT frames.
11
The event
Run Q-scan on RDSs/full frames and on all available instruments
in the network of detectors.
Mab, Tomoki,
V1 qscan, H1, H2, L1 qscan
Feb 18, 2009
12
The event
Run Event Display on RDSs/full frames and on all available instruments
in the network of detectors.
13
The event
What is the overall time-frequency volume of the event in each detector?
Does it look consistent?
14
The event
What is the expected background for such a candidate?
What is the significance of the observation given the background?
Compare background estimated from time-slides and from
first-principle Poisson estimates. Is it consistent?
15
The event
How robust is the background estimate? Do randomly-chosen shifts
as opposed to fixed shifts- is the result consistent? How about other steps?
16
The event
How robust is the significance of the event to the threshold
chosen? Do a "stair-case" analysis (varying threshold) to
appreciate this.
17
The event
If more than 2 IFOs are involved in the event, would any
2-IFO pair be able to identify it as well and with what
background/significance?
18
The event
If only 2-IFOs are involved, why it was not detected by the
rest of the detector network?
19
The event
Examine the status of the detectors not involved in the event
and establish why this is so.
20
The event
Examine frequency content out to the KHz range- is there anything
there? Will a broader bandwidth search pick it up?
21
The event
Run parameter estimation code.
22
The event
Identify the sky ring/sky patch using non-coherent methods,
i.e., signal timing and amplitude
23
The event
Compare source reconstruction between coherent and incoherent methods
24
The event
What fraction of the network's acceptance comes from this direction?
25
The event
How robust is the candidate against the stride size/start of the analysis?
26
The event
How the peak times established by the method, parameter estimation
and the various coherent methods compare? Is this as expected?
27
The event
Could it be an artifact of the prefiltering?
28
The event
What is the detection efficiency for the search method
calculated near to the candidate event? average/low/high w/r/t the S5?
29
The event
Could there be any effect from lines not filtered enough and/or
any other artifact? Could it be violin mode excitations? Any other
mechanical resonances sneaking in?
30
The event
How stationary were the instruments around the time of the event?
Quantify this both in terms of singles counting and PSD.
31
Vetoes
What could have caused this event other than astrophysics?
32
Vetoes
Are there obvious environmental disturbances in the Q-scan/Event Displays?
33
Vetoes
Are there obvious interferometric disturbances in the Q-scan/Event Displays?
34
Vetoes
Examine what known earthquakes occured around the time of the event.
35
Vetoes
Contact power companies and obtain known power line transients
around the time of the event.
36
Vetoes
If available, check in/out records for trucks and heavy equipment
to the Lab that might not have been recorded in the ilog. Check
for overpassing airplanes (airport flight logs).
37
Vetoes
Check for any switching of major electrical equipment around the time
of the event that might not have been recorded in the ilog
38
Vetoes
What are the KleineWelle (KW) triggers in auxiliary channels
around the time of the candidate?
39
Vetoes
If there are any overlaps with KW trigger from auxiliary channels,
what is the expected background of such coincidence and what is the
significance of that channel as a veto channel?
40
Vetoes
Which of the overlapping channels are safe, which are not?
Analyze most recent hardware injections.
41
Vetoes
For PEM/AUX channels with measured transfered functions, is the
signal present in the them consistent with the one in the GW one?
42
Vetoes
If nothing in the non-GW channels in the RDS, proceed with scanning
full frames and repeat above checks.
43
Vetoes
Any known data quality flags overlapping with event? How is this
dependent on DQ flag threholds? What is the coincidence significance?
44
Vetoes
Examine minute trends/Z-glitch/glitch-mon data.
Occurred during a period of ~4 minutes when H1 was highly glitchy.
Could be related to elevated low-freq seismic noise seen at that time.
Peter Sh
details
Feb 19, 2009
45
Coherent Analysis
Run the H1-H2 Q analysis; anything in the H1-H2 null stream?
46
Coherent Analysis
Run the r-statistic cross-correlation over all detector pairs
(involved or not in the trigger); how significant each is?
47
Coherent Analysis
Run coherent analysis/null stream burst analysis on the
available detector network.
48
Coherent Analysis
Run the inspiral multi-detector coherent analysis on the available
detector network and compare to the burst one.
49
Coherent analysis
What is the best fit waveform extracted from the data?
50
Other methods
Do other burst ETGs find the event(s)? If yes, compare
extracted event parameters, including background/significance.
51
Other methods
What is the outcome of the Inspiral and/or Ringdown search
around the time of the burst event? If something is present,
what is the background/significance?
52
Calibrations
What is the calibration constants and errors around this event?
53
Calibrations
How robust is the event analysis against calibration version?
54
Calibrations
Could there be any calibration artifact?
55
Calibrations
Is the event identified when analysis is run on ADC data?
Compare findings of an analysis starting with ADC(t) vs h(t).
56
Miscellanea
Check timing system of the instruments (well in sync?).
57
Miscellanea
Check for any recent reboots, software updates/reloads.
Any suspecious acquisition software changes?
58
Miscellanea
Check recent logins to the various acquisitions computers.
59
Other GW detectors
Any signature in the non LSC-VIRGO detectors? TAMA/bars online?
60
Other GW detectors
What is the expected signal size given what we know for the event?
61
non-GW detectors
Any known or "sub-prime" event in E/M or particle detectors around the globe?
62
Astrophysics
Any known sources overlapping the ring/patch on the sky
corresponding to the direction of the candidate event?
63
Astrophysics
Examine events (other than the candidate) reconstructed at the
same direction. Perform a directional search; if a point source
is behind this, more, lower SNR events might be in our data.
64
Astrophysics
How the extracted waveforms compare to astrophysical waveforms?
What is the energy scale going into GW, assuming galactic distances?
65
Vetoes
Create a hardware injection starting with signal waveforms
corresponding to the best fit waveforms extracted from the instruments.
66
Other methods
Take the extracted waveform per IFO and run matched filtered
search in order to establish how often the specific morphologies
appear in the data.
67
The event
Run the Q-event display
68
The event
Run the Coherent-Event-Display (CED)
69
Vetoes
Play audio files corresponding to GW, H1+-H2, auxiliary channels
70
Vetoes
Check that signal is the same in all photodiodes.
71
Vetoes
Check wind speeds
72
Vetoes
Check for fluctuations in power levels of TCS laser
73
Vetoes
Do a seismic Q-scan
74
Vetoes
Check on laser safety passcard records to see if anyone
was in a site LVEA or outbuilding during or near the event
75
The event
Check the QOnline analysis around the event
76
Vetoes
Check for cosmic ray events in LIGO's CR detectors
77
The event
Study time dependence of the signal frequency; does it vary?
78
Vetoes
Verify that auxiliary channels are working properly.
Check rate and BLRMS minute trends for suspicious activity.
79
Vetoes
Check level of upconversion in the instruments.